Pedicle screw insertion has been known to have several complications even in the most skilled surgical hands. However, injury to the thoracic aorta during pedicle screw insertion is rare, delayed presentation secondary to pseudoaneurysm is even rarer, the pseudoaneurysm formation caused by a series of malpositioned pedicle screws has perhaps not been reported so far.In this paper, we report here a case in which inadvertent injury to the thoracic aorta resulted in pseudoaneurysm, its manifestation was initially vague, resulting in a delayed diagnosis. Delayed aortic pseudoaneurysm or injury can be asymptomatic for a long time. Patients with renewed or continued back pain should alert orthopaedic surgeons regarding the possibility of pseudoaneurysms, regardless of the period that has elapsed after pedicle screw implantation. Delayed aortic pseudoaneurysm or injury can be asymptomatic for a long time. Patients with renewed or continued back pain should alert orthopaedic surgeons regarding the possibility of pseudoaneurysms, regardless of the period that has elapsed after pedicle screw implantation. Pedicle screw insertion is one of the most commonly performed spinal surgical procedures. Given the fact that the instrumentation results in stabilization of all three spinal columns, its use is considered the gold standard while performing fixation for various spinal conditions. Iatrogenic pseudoaneurysm is a rare and dangerous complication during pedicle screw instrumentation surgeriesWe present a case of aortic pseudoaneurysm formation after pedicle screw instrumentation and reviewed the available literature about such injuries. Key learning points, management techniques, and avoidance are discussed.11 to L2 by a computed tomography (CT) examination. The patient complained of severe back pain. There was no neural deficit. The patient underwent thoracolumbar pedicle screw implant surgery using ‘freehand technique’ under fluoroscopic guidance in a local hospital. Eight pedicle screws with contoured rods were placed spanning T11 to L2 after the correction of deformities. The patient tolerated the procedure well and developed no neurodeficits postoperatively. Radiological examination revealed a partial correction of the deformity.A 21‐year‐old man presented to the emergency room (ER) complaining of stomach and serious back pain 2 months after spinal surgical intervention. Two months before his visit, he fell from a 10 m tall building. He was confirmed as suffering fracture and dislocation from TThe patient was presented with a recurrence of pain at the operated site 10 days postoperatively. The pain was a dull ache, non‐radiating, and showed a progressive increase in intensity. This was accompanied by constitutional symptoms like poor appetite and a general feeling of being unwell. In view of the non‐specific nature of the complaints, no further investigation was carried out and the patient was advised to attend regular follow‐ups.11, T12, and L1 levels, which was a disaster. The left side T12 and L1 malpositioned screws had exited the lateral pedicle cortex and were clearly abutting the posteromedial aspect of the descending thoracic aorta (Fig. 11 and both sides of T12 screws also had exited the lateral pedicle cortex and were abutting the wall of the pseudoaneurysm. The left side screw in L2 perforated the lateral pedicle cortex but did not abut the aorta (Fig. in situ so as to avoid any chance of re‐injury. The patient endured the surgery well and had a good recovery in his 4‐month follow‐up examination.In our hospital, enhanced CT and X‐rays were performed after thorough clinical evaluation. The CT scan revealed the malposition of a pedicle screw on both sides at the TAcute aortic injuries caused by pedicle screw implantation have been reported previouslyDelayed aortic injuries have a different clinical presentation from acute ones Table . In acutThe aorta extends along left side of the thoracic and lumbar vertebrae. Quite expectedly, in this case and other studies Table , aortic in vivo bovine study, Faro et al. evaluated histological and biomechanical changes in thoracic aorta wall tissue resulting from intentional severe vessel impingement. During the 12‐month follow‐up period, the authors demonstrated that marked vessel impingement resulted in acute and chronic histopathological changes that significantly compromised vessel wall integrity on biomechanical testingDelayed aortic injuries could present over a wide spectrum and include perforation, pseudoaneurysm formation, and even complete ruptures of arterial walls, which could be fatalet al. reported a case with malpositioned pedicle screws 14 months after surgery. The surgical team re‐intervened and removed the malpositioned screw from the T6 vertebra. Three weeks later, the patient suffered fever and hemorrhagic shock and was diagnosed as having a pseudoaneurysm and bleeding from the aorta. Subsequently, the patient had to undergo re‐exploration anteriorly with vascular surgeryFor malpositioned screws with obvious injured aortic walls, revision surgery is needed. But the potential risk of complete rupture of the aorta should be considered and appropriate strategizing is required. Choi Controversy exists in the accidental finding of asymptomatic patients. Sometimes, screws have slight contact with the aorta. The integrity of the aortic wall may not have been compromised in such cases. When such screws are seen in postoperative imaging in an asymptomatic patient, the surgeon must decide whether it is riskier to revise the screw or to not do any intervention and merely observe it.Foxx retrospectively reviewed 182 consecutive patients, 680 pedicle screws undergoing spinal implants, and found 33 screws were in contact with a major vessel on routine postoperative imaging. Foxx had a mean follow‐up of 44 months and revealed no detectable vessel abnormality in subsequent follow‐ups. He recommends consideration of the overall life expectancy of the patient before contemplating any interventionet al. suggested that it is not mandatory to remove all pedicle screws found to be encroaching on major vascular structures. In cases in which the screw is not revised, regular radiographical follow‐up is required to detect the formation of a delayed pseudoaneurysm or another secondary vascular injuryet al. followed up a patient with malpositioned pedicle screws for 6 months. Unfortunately, the screw penetrated the thoracic aortic wall, and a vascular surgery had to be performedSome surgeons removed only the screws that show higher potential riskDelayed aortic pseudoaneurysm or injury can be asymptomatic for a long time. Patients with renewed or continued back pain should alert orthopedic surgeons regarding the possibility of pseudoaneurysms, regardless of the period that has elapsed after pedicle screw implantation.


MicroReview, considering the discoveries made in a pioneering transcriptome analysis performed on Listeria monocytogenes as a starting point, we discuss the progress in understanding the biological meaning of overlapping transcription that has given rise to the excludon concept. We also discuss new conditional transcriptional termination events that create antisense RNAs depending on the metabolite concentrations and new genomic arrangements, known as noncontiguous operons, which contain an interspersed gene that is transcribed in the opposite direction to the rest of the operon.In the last decade, the implementation of high‐throughput methods for RNA profiling has uncovered that a large part of the bacterial genome is transcribed well beyond the boundaries of known genes. Therefore, the transcriptional space of a gene very often invades the space of a neighbouring gene, creating large regions of overlapping transcription. The biological significance of these findings was initially regarded with scepticism. However, mounting evidence suggests that overlapping transcription between neighbouring genes conforms to regulatory purposes and provides new strategies for coordinating bacterial gene expression. In this  Overlapping transcription between the mRNAs of the neighbouring genes is a common process in bacteria. The resulting paired RNAs are digested genome‐wide by the action of the double‐stranded endoribonuclease RNase III. New examples of gene arrangements where overlapping transcription plays a key role are summarised to explain our current understanding regarding how overlapping transcription may serve a general purpose of coordinating the bacterial gene expression. The results of the study anticipated a complex scenario in the bacterial genome transcription that has been confirmed by further studies in different bacteria , cis‐acting antisense RNAs (asRNAs) and long 5′ and 3′ untranslated regions (5′ and 3′ UTRs) whose transcription start sites (TSSs) or transcription termination sites (TTSs) are often located inside the coding sequence of the neighbouring gene. This review will describe how the initial observations showing frequent overlapping between transcripts of the neighbouring genes in the Listeria transcriptome   that overlaps pocR mRNA , even in the absence of antibiotics, increasing resistance to lincomycin. A three‐amino‐acid upstream open reading frame (uORF) exactly overlapping the inhibitory anti‐antiterminator sequence forms the basis for attenuation‐mediated regulation. The association of a ribosome with the antibiotic leads the ribosome to stall on the uORF, releasing the antiterminator to interfere with terminator folding and, thus, allowing read‐through into the antibiotic resistance gene  and human oral microbiomes identified numerous riboswitches, suggesting that termination‐based regulation in response to antibiotics and other metabolites is very common in Gram‐positive bacteria  but non‐motile at host‐related temperatures (37°C). Flagella biosynthesis requires dozens of genes included in a large operon (from lmo0673 to lmo0718). Most of these genes are encoded in the positive DNA strand, with the exception of lmo0673 and mogR (lmo0674), which are transcribed opposite to them. MogR is a transcriptional repressor that is essential for the temperature‐dependent transcription of motility genes  correspond to the 5′ region of genes, whereas only 0.5% of the overlapping transcripts correspond to the 3′ region. Contrary to this, overlapping between 3′ UTRs of contiguous genes in S. aureus was found to be more frequent than overlapping between 5′ UTRs    lead to the complete characterisation of transcriptomes with a precision previously unimaginable. A limitation of these methods, due to the requirement of a minimal amount of RNA for the analysis, is that they are conducted at a ‘population level’, with the resulting transcriptome being an average of the transcriptomes of millions of prokaryotic cells (Kang, McMillan, Norris, & Hoang, The authors declare to have no conflict of interest.


It is important to identify a retained fecalith and remove that infective nidus to decrease the morbidity in patients undergoing laparoscopic appendectomy for perforated appendicitis. It is important to identify a retained fecalith and remove that infective nidus to decrease the morbidity in patients undergoing laparoscopic appendectomy for perforated appendicitis. A 29‐year‐old woman presented with right lateral abdominal wall and pelvic collection due to retained fecalith post interval laparoscopic appendectomy for perforated appendicitis. She underwent exploration for fecalith retrieval successful outcome.Laparoscopic appendectomy is currently the first choice of surgical approach for an acute appendicitis due to lower rate of surgical site infections, shorter hospital stay, and better cosmetic outcome.2A 29‐year‐old woman initially presented with a 2‐week history of nonmigratory right iliac fossa pain with subjective fever. The patient's history of complaint was not typical of acute appendicitis. After unremarkable inflammatory markers and pelvic ultrasound that did not visualize the appendix, she was discharged home with a provisional diagnosis of pelvic inflammatory disease and was given oral antibiotics for 7 days.However, she represented to our emergency department (ED) with worsening abdominal pain, ongoing fever and mild nausea. A computed tomography (CT) was organized and it showed a perforated appendicitis with retrocecal abscess and a calcified appendicolith. She then had an ultrasound‐guided drainage of the abscess and was discharged home with a view of performing an interval laparoscopic appendectomy. After discharge, the patient returned to ED for persistent recurrence of a right pelvic collection involving the right iliacus and lateral abdominal wall muscle. This was again radiologically drained. A colonoscopy was performed during this presentation to exclude any primary tumors before surgery. The entire colon was examined and showed normal mucosa and appendiceal orifice.The patient then underwent a semi‐emergent laparoscopic appendectomy. During the procedure, thorough abdominal wash was performed and a drain tube placed in the right iliac fossa. The patient had an uneventful postoperative recovery, with normalization of inflammatory markers and the drain tube removed. She was then discharged home with oral antibiotics. During her follow‐up in the general surgery clinic, the histopathology reported chronic appendicitis with granulomas but the fecalith was not within the specimen. On review, it was noted that she had intermittent abdominal discomfort and a repeat of C‐reactive protein (CRP) showed that it has elevated to 41. A repeat CT scan was performed which showed re‐accumulation of the right pelvic and lateral abdominal collection with the retained fecalith Figures .Although the abscess was intramuscular, the fecalith and the pelvic abscess were going through the abdominal wall into the subcutaneous fat Figure . There w3The wound was complicated by formation of seroma, which was managed conservatively. The patient was reviewed again 6 weeks post‐operation and remained well with no further complications of her wound or pelvic abscess drainage.4An interval appendectomy for perforated appendicitis with established abscesses is widely practiced by many surgeons.There have been different recommendations for the management of a retained fecalith.This case highlights the importance of identifying and extracting a retained fecalith to decrease the morbidity associated with a persistent infective nidus. Given that the patient had a laparoscopic procedure with a failed attempt, we have decided on a different surgical access, right lateral hip approach, with the intention of a midline laparotomy if not successful. This has led to a successful resolution of her right pelvic abscess formation with no added surgical morbidity.There are no conflicts of interest.YSK: have made substantial contribution to conception of the manuscript; Been involved in drafting, writing and revising the manuscript; Obtaining patient consent, administrative work. JCK: have made substantial contribution to conception of the manuscript; Proof‐reading, writing assistant; Final approval for publication. EW: proof‐reading; Language editing; Final approval for publication. SKW: general administrative support; Proof‐reading; Final approval for publication.Patient's informed and signed consent obtained.


This paper presents an algorithm for segmentation and shape analysis of erythrocyte images collected using an optical microscope. The main objective of the proposed approach is to compute statistical object values such as the number of erythrocytes in the image, their size, and width to height ratio. A median filter, a mean filter and a bilateral filter were used for initial noise reduction. Background subtraction using a rolling ball filter removes background irregularities. Combining the distance transform with the Otsu and watershed segmentation methods allows for initial image segmentation. Further processing steps, including morphological transforms and the previously mentioned segmentation methods, were applied to each segmented cell, resulting in an accurate segmentation. Finally, the noise standard deviation, sensitivity, specificity, precision, negative predictive value, accuracy and the number of detected objects are calculated. The presented approach shows that the second stage of the two-stage segmentation algorithm applied to individual cells segmented in the first stage allows increasing the precision from 0.857 to 0.968 for the artificial image example tested in this paper. The next step of the algorithm is to categorize segmented erythrocytes to identify poorly segmented and abnormal ones, thus automating this process, previously often done manually by specialists. The presented segmentation technique is also applicable as a probability map processor in the deep learning pipeline. The presented two-stage processing introduces a promising fusion model presented by the authors for the first time. Red blood cell (RBC) images studied in this paper were obtained using an optical microscope. Optical microscope imaging is widely used in life sciences because of its simplicity, affordability and excellent capabilities in that field of study. Modern optical microscopes are often equipped with a digital camera to gather digital images of the studied structures. For example, erythrocytes whose radius is in the range of 6–8 The goal of the presented algorithm is to address that problem by proposing an approach for red blood cells images segmentation captured using optical microscope. The algorithm is capable of separating even erythrocytes which are close to each other and calculate the width to height ratio for each of them. Another goal is to show how the proposed algorithm can cooperate with CNN. The presented algorithm allows to increase the precision of segmentation in comparison with one of the state-of-the-art approaches  with cost of increased computational complexity. Authors present approach giving good results when big labelled dataset for training is not available and could be used as probability map processor in deep learning pipeline. Deep learning model is another state-of-the-art approach. The limitation of this approach is the need for a sufficiently large dataset to train the model. Our approach is a good choice when large data set is not available. It also gives slightly better segmentation precision compared with another state-of-the-art method mentioned earlier, again due to computational complexity.An approach utilizing the deep learning model as the authors’ classical algorithm pipeline results classification tool was also given. The authors’ algorithm is applicable in scientific research when the automatic calculation of erythrocytes’ number and shape are required.The main difference between the algorithms is the segmentation methods used when performing the study. Segmentation is one of the most important steps when processing images, especially medical images. Most segmentation algorithms are based on examining differences in brightness of individual pixels in an image, or combining similar pixels into groups, or using algorithms based on artificial intelligence ,2. In thIn the literature, works related to erythrocyte segmentation are based on two conceptions. The first is segmentation using image analysis whilst the second is based on neural networks. For comparison purposes, three representative segmentation algorithm examples were selected. The third algorithm  could be considered as one of the best methods for segmentation tasks. When trained on an adequate sized learning set, it gives good results .The first algorithm uses image processing to find and mark erythrocytes infected by malaria . The preThe second of the chosen segmentation algorithms presented in the paper concerns the segmentation of leukocytes and erythrocytes in blood smears. The pixel-wise classification has been combined with template matching algorithm locate and segment cell contours of leukocyte and erythrocyte regions. The presented algorithm explicitly deals with Gumprecht’s shadow problem, which is related to squashed leukocytes with hard to identify borders. This algorithm shows a similar approach to the segmentation algorithm presented in this paper. For edge-preserving, an image smoothing non-linear Kuwahara filter was used . The algBoth of these algorithms are based on image analysis. The third algorithm is based on a convolutional neural network with U-Net architecture ,7. This Algorithm 1 Authors’ algorithmInput: Microscopic erythrocytes image 16-bit depth.Output: Image containing contours and axis of erythrocytes. 1:Convert image to Grayscale. 2:Apply Mean filter (radius r = 1). 3:Apply Background subtraction using rolling ball algorithm (radius r = 100). 4:Noise Removing (Algorithm 2) 5:Initial segmentation (Algorithm 3) 6:Individual cell processing (Algorithm 4) 7:Combining individually processed erythrocytes contours and axes with original image. 8:return resultAn algorithm (Algorithm 1) was created that allows segmentation of erythrocytes in the image. The algorithm is divided into eight steps: noise removing, background subtraction, distance map, initial segmentation, morphological erosion, morphological dilation, segmentation and contour extraction with long and short axis calculation .AlgoritRemoving noise is an important step in segmentation tasks. In our approach, the initial filtering step is composed of two stages. Firstly, a median filter is used to remove noise containing bright spots and then a mean filter is used to additionally smooth the image. A bilateral filter is used to preserve the erythrocyte edges.Median filtering is one of the nonlinear image processing methods. In this technique, for each image pixel, a median value is calculated for a given neighbourhood. The calculated value replaces the considered pixel in the filtered image. If it can be assumed that a spot with brighter or darker pixels is noise, then a median filtering technique is a good choice to remove that kind of noise ,11,12. FI—input imagep and q—distance parametersA bilateral filter is a technique which is applied when noise should be removed while keeping the edges intact. This is the advantage of this method over simple Gaussian smoothing. This method uses convolution with a Gaussian kernel with the weighted average of pixels in the given neighbourhood (Equation ). This mBackground subtraction is a method used for obtaining an even distribution of background values across an image. The algorithm uses a spherical or some other differently shaped structural element, which moves on the surface resulting from the treatment of the image as a three-dimensional plot, where the image dimensions and the pixel value form its axes. While moving on this surface, the structural element cannot penetrate the narrow peaks so that the background profile can be defined for all pixels in the image and then subtracted from the image ,17. The The distance map  method cOtsu segmentation is a fast and robust method that gives good results for images with objects well separated from the background. The high speed of the algorithm is achieved thanks to using a histogram to calculate thresholds. First the histogram is computed, then the algorithm finds the threshold that minimises the weighted within-class variance which is equal to the maximising between-class variance. One or more thresholds could be calculated. Finally, the image is segmented using the computed thresholds ,20.In the watershed segmentation algorithm, a two-dimensional monochrome image is considered as a three-dimensional map where the third dimension is pixel intensity. Higher intensity values correspond to ridges and lower values correspond to valleys. The algorithm performs a flooding operation. An imaginary water level rises and floods the valleys around local the minima called catchment basins. When catchment basins are about to overflow in the next flooding step, a dam on its surrounding ridge is built to prevent the basins merging ,21.The erythrocyte images analysed in this article are processed after conversion to grayscale. The difficulties in this segmentation task are noise, uneven background and the fact that sometimes objects are not well separated. For a better uneven background visualisation, window/level transformation was applied .Algorithm 2 Noise RemovingInput: Preprocessed image.Output: Noise removed image. 1:Apply median filter (mask radius = 4). 2:Apply mean filter (mask radius = 3). 3:Rescale image to 8-bit depth. 4:Bilateral filter (domain sigma ( 5:return resultFiji implementation  of backgOtsu segmentation (ITK implementation ) was perAlgorithm 3 Initial SegmentationInput: Image with noise removed.Output: Initially segmented image. 1:Apply otsu binarization algorithm. 2:Apply filling holes algorithm. 3:Morphologically erode image (radius = 2). 4:Calculate distance map. 5:Watershed segmentation . 6:Small objects removal (sizeThreshold = 25). 7:Remove near to the edge objects border (touching pixels number threshold = 0), object is removed if at least one pixel is placed in image border. 8:return resultAlgorithm 4 Individual cell processingInput: Initially Segmented image.Output: Fully segmented image. 1:for each for each each long axis point find short erythrocyte axis: do 2:  Select ROI—select rectangle ROI around the considered object with the given margin (margin m = 10). 3:  Create mask and dilate it (dilatation radius r = 6). 4:  Create masked image. 5:  Binarize each image using Otsu algorithm. 6:  Fill holes. 7:  Select biggest object. 8:  Get contour of the object. 9:  Calculate Euclidean distances between all contour points. Two contour points with the largest distance between them define the long axis. 10:for each long axis point find short erythrocyte axis: do   11:    Find perpendicular to long axis, straight line through the point being considered. 12:    Find all contour points with a distance to that line less or equal to sqrt(2). 13:if At least two contour points with distance between them larger than threshold (t = 4) do not exist: then     14:     Go to the next long axis point. 15:else     16:     Consider two points with largest distance between them as two cluster positions. 17:     Assign all others points to clusters based on Euclidean distance criterion. 18:for each cluster: do      19:      Select one point closest to the considered straight line. 20:     Label selected points pair as cross point candidates and calculate distance between them. 21:if selected points pair distance is greater than for pair tested before: then      22:      Mark considered points pair as cross points. 23:if selected points pair distance is equal to distance for pair tested before: then      24:      select pair with line connecting them passing through the point closest to the long axis center and mark as cross points 25:if no cross point candidates pair exist: then     26:  Go to the next erythrocyte (short axis cannot be determined). 27:return resultWatershed segmentation (ITK implementation ) appliedAfter initial segmentation (Algorithm 2), each identified object is processed individually. For each object, a rectangular region of interest with a small margin on each side is considered. If there are objects placed near to one being considered, then their location is utilized to create a mask b. AnotheOtsu segmentation performed on the filtered image region of interest combined with the mask obtained in the previous step produces a segmented image with darker (green) and brighter (blue) classes a. ErythrTwo contour points with the largest distance between them define the long axis . The shoPoints with a distance less than or equal to √2 are considered as cross point candidates. If at least two candidates are present and at least two candidates have a distance between them larger than the threshold, the algorithm proceeds. Two candidates with the largest distance between them are selected and are considered as the two cluster positions. All other candidates are assigned to one of the clusters based on Euclidean distance criterion. For each cluster one point closest to the considered straight line is selected and identified as a cross point. This procedure is repeated for all long axis points. The longest line becomes the short axis. If more than one line is the longest, only the one passing through the point closest to the long axis centre is selected.The approach presented by authors could act as a processor for probability maps resulting from deep learning pipelines. For this paper, the image set BBBC038v1  was usedThe authors’ algorithm could be extended using deep learning techniques. The authors used this algorithm to segment 13 red blood cells images, obtaining 1339 individual cell images. Those images were arbitrarily divided into three categories: normal (1021 items), abnormal (88 items) and wrongly segmented (230 items) red blood cells . The datThe authors used a transfer learning approach building a model from MobileNetV2 model  with weiMost of the cells on the studied images were well segmented. Red blood cells which are close to each other are separated. For all segmented objects, the contour and both long and short axes were found . To evalThe algorithm output binary image provides a base for artificial mock image construction. All objects and background pixel positions are known so the algorithm segmentation result obtained using that image can be statistically evaluated. The relevance for that method of algorithm evaluation is correlated to the level of similarity between the artificial and original images. Background and object intensity values were set to be similar to the original image.In optical microscope images, such erythrocytes in the inner area have intensity values greater than those near the edge. The binary image was eroded to obtain that inner area. The background was altered using a two-dimensional Gaussian function to imitate the original image background profile. The original background is brighter near the centre of the image and darker when moving towards the edges. Gaussian smoothing was applied to imitate the original objects’ blurred edges, then noise with few defined values of standard deviation was added .A few combinations of that step with different parameter values were tested and statistical evaluation measures of binary classification such as sensitivity, specificity, precision, negative predictive value, accuracy and the number of detected objects were calculated .The method was checked for initial segmentation correction—without individual erythrocyte processing step . Two difMoreover, the algorithm was tested on randomly cropped and rescaled images. The test set was created using the mock image mentioned earlier created with Gaussian smoothing radius equals 3 and noise standard deviation equals 6. The image was randomly cropped five times and then each cropped image was additionally rescaled with 0.7 and 1.3 scaling factors resulting in a test set containing 15 images with different aspect ratios and sizes (width or height vary from 322 to 1333 pixels). The obtained results  show thaAs a conclusion, according to the results presented in The presented approach could be used to expedite RBC image analysis tasks where real-time processing is not needed due to high computational complexity. Initial segmentation time dependents on image size. Individual cell processing time dependents on image size, object size and number of objects selected for processing see . For theNoise filtration and background subtraction algorithms used by the authors in this step are described in this paper. Evaluation of the results shows that both algorithms detected the correct number of objects. Considering precision  as evaluation metrics, the standard approach results in slightly better segmentation for the two least distorted mock images .The image processing algorithm combination presented in this paper is a mix of known and widely used methods in a way that we found suitable for solving the given problems. It is worth mentioning that it is not a universal algorithm because of the computational complexity resulting from the usage of many image processing techniques in the algorithm pipeline. The algorithm is therefore not suitable for use in real-time applications but it is not a disadvantage in erythrocytes segmentation tasks where the speed of segmentation is not a must.Despite the fact that the used individual methods considered separately are not new, the use of two stage processing is a novel combination of these methods. The use of second stage processing applied to individual cells allows us to increase precision from 0.857 to 0.968 for an artificial image example .Combining CNN with image processing algorithms in a way appropriate to the considered problem can give good results. Two approaches described in this paper are good examples of such synergy.Artificial neural network-based methods (U-net for example) give good segmentation results but in many cases post-processing using classic image processing methods is necessary. Simple thresholding or watershed and distance map combined segmentation are often applied as postprocessing techniques for U-net probability maps. Moreover, considerable large image sets segmented by an expert had to be used to train such networks. Classic image analysis methods could help the artificial neural network-based methods achieve better results and be applied to tasks where large expert labelled image sets are not available or in the approach described in The authors are currently working on the further development of their algorithm. The work will be extended by automatization of the process of selecting parameters of particular methods as well as an adaptation algorithm to accept images regardless of their colour intensity. Changes may also affect the method of segmentation of erythrocytes in the microscope image.


Immunohistochemistry of lung specimens was compatible with a diagnosis of malignant melanoma which was confirmed to be BRAF wild‐type. Furthermore, positron emission tomography (PET) and contrast‐enhanced magnetic resonance imaging (MRI) of the head revealed multiple metastatic lesions in the brain, liver, and bones. The patient was referred to another hospital for specific treatment. After that, the patient's melanoma was confirmed to have the BRAF wild‐type gene and PD‐L1 expression was 80%. Then, combined therapy of nivolumab plus ipilimumab was subsequently administered.A 47‐year‐old Japanese man was referred to our hospital with a one‐week history of chest discomfort. Chest computed tomography (CT) revealed a mass in the right upper lobe suspected to be primary lung cancer. A biopsy of the mass using endobronchial ultrasonography (EBUS) with guide sheath (GS) was performed, and a black‐colored mass was observed which occluded almost all of the right B Black pigmentation of the airways (black bronchoscopy) can be caused by many etiologies. We herein reported a case of black bronchoscopy for pulmonary malignant melanoma.


Prior to the COVID‐19 pandemic, laryngoscopy was the mandatory gold standard for the accurate assessment and diagnosis of inducible laryngeal obstruction. However, upper airway endoscopy is considered an aerosol‐generating procedure in professional guidelines, meaning routine procedures are highly challenging and the availability of laryngoscopy is reduced. In response, we have convened a multidisciplinary panel with broad experience in managing this disease and agreed a recommended strategy for presumptive diagnosis in patients who cannot have laryngoscopy performed due to pandemic restrictions. To maintain clinical standards whilst ensuring patient safety, we discuss the importance of triage, information gathering, symptom assessment and early review of response to treatment. The consensus recommendations will also be potentially relevant to other future situations where access to laryngoscopy is restricted, although we emphasize that this investigation remains the gold standard. Typical clinical symptoms [eg difficulty breathing in, throat tightness/discomfort, voice disturbance Flexible fibreoptic laryngoscopy during a symptomatic episode is the gold standard for ILO diagnosis.1.3The impact of the COVID‐19 pandemic upon healthcare provision has been profound globally. In the UK, most respiratory elective activity was suspended in March 2020. Hospital‐based respiratory clinicians continue to manage acute COVID‐19 patients whilst, at the same time, attempting to coordinate a safe return to elective services.Upper airway endoscopy has the potential to generate aerosols through sneezing and coughing;Internationally, the impact of COVID‐19 pandemic remains a highly variable situation. As the pandemic evolves, the accessibility to endoscopic evaluation of the larynx is likely to be scaled according to pandemic severity and the rate of community transmissions within geographical locations. Further, the resources available  and workforce logistics  will have significant impact on the delivery of care.1.4A multidisciplinary team (MDT) approach improves diagnostic precision and facilitates a meaningful clinical impact in ILO.accurately confirm or refute ILO diagnosisdirectly assess structure and function in the upper airway and rule out mimics that include serious structural issues requiring immediate surgical intervention (eg subglottic stenosis).assess relevant differential diagnoses inform treatment regimens specific to the individual patientprovide biofeedback (to the patient) and teachingmonitor therapeutic responseThe inability to perform an endoscopic evaluation of the larynx and/or continuous laryngoscopy during provocation limits the MDT’s ability to:data on file). It may be that symptom‐based questionnaires such as the Pittsburgh Vocal Cord Dysfunction IndexClinical symptoms can be used only as a guide, and without usual access to objective testing, it is not possible to confirm an accurate diagnosis. Over‐diagnosis without laryngoscopy is a particular concern in this context. In 303 patients with a high clinical suspicion of ILO , we confirmed laryngoscopic appearances in only 74% , represents six UK specialist centres, all of which have established MDT provision for patients with ILO and airways disease. An adaptation of the nominal group techniqueTo manage any potential dissention during the statement production, a pre‐determined level of what would constitute consensus agreement was discussed at the outset. However, no such dissention occurred. This statement constitutes the expression of general opinion of all the group experts.22.1The profound reduction of access to laryngoscopy has necessitated the consideration of alternative approaches to ILO diagnostic and treatment pathways. Other instrumental assessments may be beneficial to detect ILO, including spirometry and dynamic computerized tomography (CT) scanning.All patients should be managed through a dedicated MDT ;Management decisions should be guided by the consensus recommended clinical pathway Figure ;“Suspected ILO” is the term given until an endoscopic evaluation is available to give a confirmatory ILO diagnostic label.A pragmatic approach to the assessment of ILO is therefore important to minimize ILO morbidity where possible. Diagnosis must rely heavily on clinical clues and be guided by results of previous investigations in order to exclude other causes of symptoms, primarily breathlessness. To minimize risk of potential misdiagnosis (both under‐ and over‐diagnosis), we recommend the following:2.2The overall aim of the clinical pathway Figure  is to su2.3Persistent dysphoniaPersistent noisy breathingThroat pain/ odynophagiaHaemoptysisSmoking/ alcohol excessUnintentional weight lossInitial triage should identify key risk factors (“red flags”) for sinister pathology and if present, the receiving team should consider whether rapid onward referral is appropriate. In the absence of endoscopic evaluation of the larynx (and lower airway), it is essential a low threshold is applied. Risks for onward referral includ 21), and any patient‐held (ie “selfie” type) video/ audio recordings made during symptomatic episodes. This may include recordings taken during exercise, providing this is conducted with patient safety appropriately considered.To assist MDT assessment, review of previous investigation data is vital. We recommend referrers provide as much existing data as available to support this Table . If this2.4If a patient has not had a respiratory review in the last 12 months this should occur prior to MDT assessment, with the aim of identifying other potentially treatable respiratory diseases that may be responsible for the presenting symptoms. MDT assessment and discussion of the likely diagnosis should follow, supported by the referral data obtained.Specific consideration should be given to symptoms consistent with ILO but that may occur due to other factors. Emphasis on excluding uncontrolled asthma as a cause of breathing difficulties is a priority, but other common and important differential diagnoses to consider include breathing pattern disorders, and structural or inflammatory laryngeal and large airway pathology. This will prove challenging as access to lung physiology and bronchoscopy is also restricted.Suspected ILO following MDT assessment and discussion;Suspected ILO likely cause of respiratory symptoms in patients with co‐existent disease (eg symptoms not attributed to breathing pattern disorder/ asthma);Other interventions not indicated ;Patient consents to empirical SLT treatment, based on a presumptive ILO diagnosis.Suitability for ILO intervention should be based on patients meeting the following criteria:At the time of publication, restrictions in performing respiratory instrumental assessments remain and even in a scenario whereby limited access to procedures becomes available, contingency plans need to be in place for further outbreaks or “second‐wave” surges. Consideration should be given to those patients deemed high priority for endoscopic evaluation (laryngoscopy ± bronchoscopy) as services begin to resume and access improves. It is likely that those patients identified as a high priority for laryngoscopy will similarly be a high priority for other objective tests (eg lung physiology). Even where resumption of laryngoscopy is possible, the throughput of patients will be significantly reduced due to mandated lengthy decontamination procedures between patients.We have previously considered how to prioritize patients2.5Speech and language therapy is the gold‐standard treatment for ILOdata on file, based on over 300 referrals). Coupled with a reported non‐response rate of SLT intervention in endoscopically confirmed ILO patients of approximately 30%Empirical SLT intervention  may not be appropriate for all patients. We recognize that approximately one‐quarter of patients with a high clinical suspicion of ILO do not have confirmed laryngoscopic appearances (26) and Newcastle Laryngeal Hypersensitivity QuestionnaireConsidered review of treatment response is essential to minimize the risk of missing alternative pathologies and avoiding perpetuating an incorrect presumptive diagnosis of ILO. Objective sessional outcomes [eg clinician‐ and patient‐reported outcomes such as the Vocal Cord Dysfunction Questionnaire  that can aid patient understanding of diagnosis and therapeutic interventions.In the absence of routine laryngoscopy, the risk of misdiagnosis must not be overlooked and so it is imperative to maintain strong connections between respiratory and otolaryngology services. A research opportunity exists to investigate the diagnostic value of non‐invasive objective laryngeal assessments, such as dynamic CT, although this will clearly be currently limited by the difficulty of comparing to the gold‐standard laryngoscopy. Efforts should also be made to produce and refine validated outcome measures to better monitor therapeutic response.Beyond the pandemic, lessons learned from workforce responses to clinical delivery, digital advances in tele‐medicine and further MDT integration patient management, present opportunities to establish and develop relationships between ILO experts across the globe. We look forward to greater collaboration to facilitate collection and amalgamation of larger data sets that will help us to further understand ILO and relative management strategies.


Patients with schizophrenia are at least twice as likely to develop diabetes mellitus compared to the general population. This is of significance in Qatar given the high prevalence of obesity and diabetes. Furthermore, the lifespan of people with schizophrenia is shortened by approximately 15 years, partly due to long-term microvascular and macrovascular complications. High quality diabetes care can significantly reduce morbidity and mortality. We assessed the level of diabetes care delivered to patients in Qatar with schizophrenia and diabetes compared to those with diabetes alone.n = 73) and without (n = 73) schizophrenia. Demographic information and electronic medical records were reviewed to determine adherence to American Diabetes Association standards of diabetes care in the last 6 and 12 months. Optimal diabetes care was defined as having completed glycated hemoglobin (HbA1c), lipid profile and retinal examination within 12 months.We performed a retrospective chart review of patients with diabetes mellitus with (n = 19/73) vs 52.1% (n = 38/73), p = 0.002]. Patients with diabetes and schizophrenia were also significantly less likely to have had body mass index recorded within 6 months (p = 0.008) and HbA1c (p = 0.006), lipid profile (p = 0.015), estimated glomerular filtration rate (eGFR) (p = 0.001) and order for retinal examination (p = 0.004) over 12 months. After adjusting for multiple comparisons, only assessment of eGFR (p = 0.01) and order for retinal examination (p = 0.04) remained significant.Optimal diabetes care was significantly lower in patients with schizophrenia and diabetes compared to diabetes alone [26.0% (Patients in Qatar with schizophrenia and diabetes, receive sub-optimal diabetes care compared to those with diabetes alone. A Canadian study using the same definition over 2 years reported very similar findings –17.Suboptimal diabetes care in our study group may be attributed to a lack of integrated physical and mental health services and difficulty sharing information and expertise amongst health care specialties . Stigma In our sample, patients with diabetes alone were significantly older compared to those with both diabetes and schizophrenia, which could reflect the earlier onset of diabetes due to lifestyle and medications used for schizophrenia . HoweverWe propose several strategies to reduce the inequalities reported. Educational awareness programs for health professionals are needed to address mental health stigma and negative stereotypes. Further work is required to increase awareness amongst HCPs regarding the increased morbidity and mortality in patients with schizophrenia. Communication between different services providing health care for patients with schizophrenia is essential to ensuring access to health care services and optimizing management of medical comorbidities. Education to prevent or limit obesity and diabetes needs to be promoted among patients with severe mental illness to help decrease the prevalence of diabetes and ensure that those diagnosed with diabetes receive high quality care. These recommendations are in line with the recently published blueprint for protecting physical health in people with mental illness .This population-based study included randomly assigned patients from both genders and all nationalities followed in outpatient clinics. Data to identify and control for the duration of diabetes and schizophrenia in our cohorts was limited as the EMRs system was started in 2015. Additionally, important demographic information such as smoking, marital and socioeconomic status were missing or inconsistently documented. Nevertheless, lab results, orders and documentation pertaining to diabetes care were easily extractible, and the criteria for optimal diabetes care were clearly defined. As this is a case-control study, the incidence and relative risk of suboptimal diabetes care in patients with schizophrenia could not be calculated.This study found that patients with schizophrenia and diabetes in Qatar are less likely to receive optimal diabetes care compared to patients with diabetes alone, particularly in relation to the assessment of microvascular complications with a decreased frequency of eGFR assessment and request for retinal examination. These data demand further larger population cohort studies to assess adherence with treatment and the burden of diabetes-related medical comorbidities and complications in patients with schizophrenia.


Liquid silicone (polydimethylsiloxane) is an inert material that is commonly used for cosmetic purpose. Silicone embolization syndrome (SES) can rapidly progress to pneumonitis as a consequence of the injection of nonmedical‐grade liquid silicone. We describe a case of severe silicone pneumonitis complicated with acute respiratory distress syndrome and bilateral pneumothorax secondary to silicone gluteal augmentation. In this case report, we aim to discuss our experience and approach in managing an uncommon case of SES. We describe a case of severe silicone pneumonitis complicated with acute respiratory distress syndrome and bilateral pneumothorax secondary to silicon gluteal augmentation. In this case report, we aim to discuss our experience and approach in managing an uncommon case of silicone embolization syndrome. For decades, Liquid injectable silicone has been used for correction of contour defect or soft‐tissue augmentation. Medical‐grade liquid silicone (polydimethylsiloxane) becomes the preferred inert material for cosmetic purpose due to its durability, a lack of immunogenicity, and thermal stability; but later found to be associated with silicone embolism syndrome (SES). Liquid injectable silicone induced embolism has been reported by several studies as a cause of acute pneumonitis with alveolar haemorrhage A previously healthy 30‐year‐old woman presented with three days history of cough with dyspnoea and fever. She had a history of breast augmentation with silicone implant two years ago and had received bilateral gluteal silicone injections from an unlicensed provider one week before the current presentation. The injected volume was approximately 500 mL for each gluteal.2, 40 mmHg; PaO2, 56 mmHg; and peripheral oxygen saturation, 90%. Lungs examination revealed bilateral lower zone crepitations. Other blood investigations which included a complete blood count, comprehensive metabolic panel, and lactate were unremarkable. She was initiated on broad‐spectrum antibiotics, oseltamivir, intravenous hydrocortisone 50 mg every 8 h, and 12 L/min (FiO2: 60%) of high‐flow oxygen supplement. However, she developed right‐sided pneumothorax and worsened respiratory failure 12 h later.The physical examination was tachycardia, tachypnoea with the respiratory rate of 28 breaths per minute and a temperature of 38°C. Results of the arterial blood gas performed while the patient was breathing room air were as follows: pH, 7.39; PaCOOn chest radiograph, diffuse alveolar opacities in both lung fields were observed. A computed tomographic scan of her thorax demonstrated diffuse bilateral ground‐glass infiltrates Fig. . FiberopShe received lung protective ventilation for acute respiratory distress syndrome ) for continued hypoxia. Unfortunately, two weeks later, she again developed another spontaneous pneumothorax on the left lung and required chest tube drainage. Over four weeks in the intensive care unit, we manage to wean down the ventilatory support. She had an excellent clinical response and discharged with tapering prednisolone over two weeks. At six weeks of outpatient follow up, she was symptom‐free, and her chest X‐ray revealed residual bilateral reticulations.The respiratory consequences that associated with silicone injection include acute pneumonitis Pulmonary SES results from silicone embolizing to the lungs from an inadvertent intravenous injection or local tissue destruction. The neutrophils ingested the embolization of the silicone material into the lung via the haematogenous or lymphatic and alveolar macrophages induces pneumonitis by local cell‐mediated inflammation and release of free radicals and proteolytic enzymes Diagnosis of the silicone pneumonitis is based on the clinical history of silicone implant or injection, the radiological pattern of subpleural infiltrates and peripherally distributed ground‐glass opacities (GGO) Survival is likely, and treatment involves ventilation if necessary and steroids with uncertain utility. The rate of mortality is directly associated with the large volumes of silicone and high‐pressure injection There is no consensus on the treatment of the silicone induced pneumonitis, but case report series show a favourable response with the use of the steroid Table  to reducCarolyn et al. reported a case of acute pneumonitis after silicone injection for gluteal augmentation. The patients presented with haemoptysis, shortness of breath, and acute respiratory failure two days after the silicone injections Srilekha Sridhara et al. reported a rare case of silicone pneumonitis with pneumothorax occurred even after 15–20 years of silicone injection Elizabeth et al. reported three cases of breast implants with the onset of symptoms ranges 2–16 years Our case demonstrates the features of SES after the gluteal silicone filler. No specific site for vascular infiltration was identified in our case; however, many injection marks were observed on the buttocks. MRI breast confirmed that there is no leak from the silicone breast implants and no residual collection in the gluteal region. Thus, the decision not to remove the breast implant and not for surgical exploration of the possibilities of remaining gluteal silicone collection was made after a multidisciplinary meeting comprises of pulmonologist, plastic and reconstructive surgeon, and anaesthetic team. A trans‐bronchial lung biopsy was deemed to be a less invasive approach to obtain lung biopsies in order to avoid the risk of general anaesthesia due to poor pulmonary reserve.The detection of HCoV‐NL63 in our patient is incidental. This is consistent with the literature that HCoV‐NL63 can be frequently found in asymptomatic individuals Corticosteroids are potentially beneficial in reduces the inflammation of the airways that leading pneumonitis with acute respiratory distress syndrome but does not have any mortality benefits Lung‐protective ventilation strategies improve survival.Vigilance in the occurrence of pneumothorax in cases of SES especially if complicated with ARDS and requiring mechanical ventilation. Risk of pneumothorax in SES and will usually resolve after chest drain intervention.Trans‐bronchial lung biopsy is useful in assisting the diagnosis.Patients should be advised that there is a risk that silicone injections can be associated with serious pulmonary complications.Learning points for our case includes:The injection of silicone for cosmetic purpose is debatable due to the sequelae of the pneumonitis and the potential for pulmonary toxicity in asymptomatic patients who receive silicone injections. Bronchoalveolar lavage and trans‐bronchial lung biopsy can help to confirm the diagnosis. This case report serves to highlight an emergent danger associated with illicit silicone use for cosmetic purposes and clinicians should be aware of the potential complications.Appropriate written informed consent was obtained for publication of this case report and accompanying images.


With nearly 100 million people affected in the United States with nonalcoholic fatty liver disease (NAFLD) and projections for the advanced stages of NAFLD to soon become the leading indication for liver transplantation, nonalcoholic steatohepatitis (NASH) remains a significant area of unmet medical need. Therapeutic options for NASH are a critical priority for clinicians, drug developers and regulatory authorities. The epidemic proportions have led to a surge in the development of novel drugs aimed at the complex pathogenesis of NASH and in regulatory submissions. There are currently no approved drugs in the United States for the treatment of adult or paediatric NASH. Potential therapeutic targets include steatosis, glucose metabolism, lipogenesis, oxidative stress, apoptosis, fibrosis and immunomodulation, all intended to alter the pathophysiology of NASH and remedy its associated complications.While over 50 candidate drugs are currently under development in the United States, it has yet to be determined the extent to which single agents will be impactful on the multifactorial aetiology of NASH based on publicly available preliminary data.The FDA currently supports commercial drug development in NASH with advanced stage fibrosis as these patients are at a higher risk for liver‐related adverse clinical outcomes. There are two types of regulatory approval pathways: traditional  and accelerated approval. Traditional approval relies on clinical benefit end‐points which directly measure how a patient feels, functions and survives  and would require durations in the order of decades for trials in precirrhotic NASH patients.Accelerated approvalFDA draft guidance regarding drug development in noncirrhotic NASH with liver fibrosis was published in 2018The target population for these trials should have a histological diagnosis of NASH with liver fibrosis based on a NAFLD activity score (NAS) equal to or >4 with at least 1 point each in inflammation and ballooning in addition to a NASH Clinical Research Network fibrosis score of stage 2 or 3 prior to enrolment. Currently, there is no specific weight criterion for enrolment, but weight should be stable for at least 3 months prior to enrolment. Patients with T2DM can also be enrolled in NASH clinical trials if at least moderately controlled and on stable doses of anti‐diabetic medications for at least 3 months. Concomitant medications with the potential to confound the interpretation of efficacy or safety, for example by contributing to the therapeutic effect of a drug for NASH (eg Vitamin E or pioglitazone), should either be discontinued or have been on a stable dose for at least 6‐12 months.Biopsy‐based end‐points of (a) resolution of steatohepatitis on overall histopathologic interpretation and no worsening of fibrosis, (b) one or more stage reduction of fibrosis with no worsening of NAS or (c) both improvement of NAS and fibrosis are the primary basis to support accelerated approval. A candidate drug's effect(s) on the end‐point(s) will be dependent on the mechanism of action of the drug with a potential for improvement in either NAS or fibrosis, both or neither in an individual patient. Phase 4 (post‐market) confirmatory trials verifying the clinical benefit of these histological end‐points and using composite outcome end‐points of progression of cirrhosis, reduction of decompensation events, changes in model for end‐stage liver disease (MELD) score, liver transplant and all‐cause mortality, should generally be underway at the time of submission of the marketing application for accelerated approval. End‐point selection and planned statistical testing should be discussed with the FDA review division on a case by case basis.The guidance was posted for public comments in December 2018.Presently, there are 734 global NASH studies in various stages of completion, of which 298 are being conducted in the United States.The described limitations and complications of biopsy assessments support the urgent need of noninvasive diagnostic tools through increasing research and fit‐for‐purpose use. Currently, multiple biomarkersDGIEP has employed the recommendation of a much smaller alpha  to achieve statistical significance for biopsy‐based NASH end‐point(s) in phase 3 trials and allow greater certainty in predicting the relationship between histology and clinical benefit. Another increasingly recognized challenge that is essential to trial design is maintenance of ongoing trial conduct and integrity after accelerated approval or public dissemination of interim data which should be prospectively planned. A detailed unblinding plan, careful selection of database lock and cut‐off date, projections of patient adherence and retention, subject awareness through updates to the informed consent document, and measurement of operational characteristics over time are important considerations for maintaining post‐approval, ongoing trial integrity.For clinical outcome trials, there may be drivers of the clinical benefit end‐point (eg progression to cirrhosis component may contribute a greater number of events as it will occur more frequently than other components comprising the composite end‐point); while this may allow earlier completion of trials in a shorter duration, it may not evaluate all aspects of the disease and this will need to be factored into the data review and analysis to ensure that a positive treatment response is not an isolated effect.FDA draft guidance regarding drug development in NASH with compensated cirrhosis was published in 2019.At present, FDA recommends that clinical trial protocols in populations with NASH with compensated cirrhosis not exceed 25%‐30% cryptogenic cirrhosis patients, a proportion similar to that expected for the upper rangeThe primary safety conundrum for NASH drug development is that investigational agents intended to treat liver disease can also result in liver injury.It has been estimated that as many as 75% of patients with obesity have NAFLD and 20% have NASH.2 or greater than or equal to 27 kg/m2 in the presence of weight‐related co‐morbidities are thought to be at significant risk for weight‐related morbidity and mortality that would justify the use of drug treatment. The draft guidance cites the examples of T2DM, hypertension, dyslipidaemia, sleep apnoea and cardiovascular disease as weight‐related co‐morbidities. Although not specifically discussed in the draft guidance, obesity drug trials likely enrol many patients with NAFLD given the overlap in these populations. Special attention should be given to enrolment criteria and safety monitoring plans when including a significant proportion of NASH patients, particularly in those drug development programmes that have demonstrated potential for nonclinical and/or clinical signals of liver toxicity.The most recently updated FDA draft guidance for weight management was published in 2007.Weight change from baseline is the primary efficacy end‐point in placebo‐controlled trials for obesity drugs, and the guidance specifies that weight loss should be demonstrated over the course of at least one‐year duration. The goals of weight loss in obesity management are to prevent or slow the progression of obesity‐related health outcomes and improve quality of life. Weight loss of 5 per cent—evaluated as mean change from baseline and in a categorical analysis of the proportion of patients losing 5 per cent body weight—is generally considered clinically meaningful in patients with obesity as it has been associated with improvements in cardiometabolic biomarkers, such as blood pressure, lipids and fasting glucose.There are currently 5 drugs that are FDA‐approved for chronic weight management in patients with obesity: orlistat , lorcaserin (serotonin 2C receptor agonist), phentermine/topiramate (combination of a sympathomimetic anorectic and an antiepileptic drug), bupropion/naltrexone (combination of an aminoketone antidepressant and an opioid antagonist) and liraglutide (GLP‐1 receptor agonist). One‐year placebo‐subtracted weight loss from baseline body weight as described in the prescribing information ranges from 3% to 9% and depends to a large extent on the patient population, background lifestyle intervention, treatment adherence, study discontinuation rate and the statistical methods used to address missing data. The labelled prescribing information for these drugs includes changes in weight‐related secondary end‐points, such as blood pressure and lipids, but currently does not include liver‐related efficacy end‐points, or claims related to the reduction of cardiovascular morbidity and mortality or improvement in quality of life. To date, no obesity drug has demonstrated cardiovascular risk reduction in a dedicated trial.Obesity and severe obesity in children and adolescents ages 2 and above are often defined as a BMI at or above the 95th percentile of sex‐specific BMI‐for‐age and BMI at or above 120% of the 95th percentile, respectively.Currently, there are limited pharmacological treatment options in children and adolescents with obesity, with only one drug, orlistat, labelled for long‐term weight management in patients ages 12 and above. The assessment of certain drugs and biologics in children is required under the Pediatric Research Equity Act,Paediatric studies in NASH are few and, as with adults, there are no FDA‐approved drugs. While several drug manufacturers have identified the need for paediatric studies in NASH as early as possible in their initial paediatric study plans, the path forward is less clear because of the differences in adult and paediatric NASH histopathologic features making it impracticable to extrapolate efficacy from adult data to children, lack of natural history information to define feasible end‐points, ethical and regulatory requirements that enrolment of children in drug intervention trials be adequately justified through demonstration of prospect of direct benefitHistorically, drugs used to treat obesity have focused on the primary end‐point of weight and amelioration of traditional weight‐related co‐morbidities, such as T2DM and dyslipidaemia. However, given the overlap of these conditions with NAFLD, drugs to treat obesity are being considered for treatment of NASH.Drug development and regulatory pathways in metabolic and endocrine disorders are increasingly intersecting with NASH through overlapping patient populations, drug classes and mechanisms of action, end‐points and clinical trial designs. At least 25% of the active NASH Investigational New Drug (IND) submissions within FDA have benefited from collaboration between DGIEP and DMEP. Similarly, programmes regulated within DMEP for metabolic diseases such as obesity and dyslipidaemia have explored liver‐related end‐points and enrichment with NASH populations. For these reasons, patients with NASH could be specifically targeted in obesity and other metabolic drug programmes to enrich for cardiometabolic risk factors, or to evaluate NASH end‐points as part of the efficacy assessments to support obesity drug approval. However, equating benefit from one metabolic disorder to the next may be more complicated than foreseen even if it were possible to attribute relatedness of differential outcomes . As this is a fairly novel approach in already complex pathophysiology, drug manufacturers and investigators are encouraged to discuss such study proposals with the Agency.Examples of overlapping drug classes or mechanisms in the pipeline for NASH and other metabolic diseases include glucagon‐like peptide‐1 receptor agonists, peroxisome proliferator‐activated receptor agonists, sodium glucose cotransporter‐2 inhibitors, fibroblast growth factor‐21 analogs, and others.A fresh look at the Venn diagram of the pathophysiology for these metabolic diseases may be needed to develop emerging treatments aimed at common pathways in addition to downstream effects. The convergence of risk factors, patterns of injury, drug mechanisms of action, biomarkers, outcomes and regulatory frameworks may prove insightful in generating the next wave of therapeutic options. The future remains exciting and promising for NASH drug development.The authors declared no conflict of interest.SOO conceived the concept for the manuscript and is the primary author. JKG authored sections on drugs to treat obesity and other metabolic diseases. Both authors contributed to the preparation and revision of the manuscript.The authors declare that the manuscript is original and has not been submitted for publication elsewhere. No specific ethical approval or informed consent was required for this editorial.


PDE type 5 inhibitors (PDE5Is), such as sildenafil, tadalafil and vardenafil, are a class of drugs used to prolong the physiological effects of NO/cGMP signalling in tissues through the inhibition of cGMP degradation. Although these agents were originally developed for the treatment of hypertension and angina, unanticipated side effects led to advances in the treatment of erectile dysfunction and, later, pulmonary arterial hypertension. In the last decade, accumulating evidence suggests that PDE5Is may confer a wider range of clinical benefits than was previously recognised. This has led to a broader interest in the cardiovascular therapeutic potential of PDE5Is, in conditions such as hypertension, myocardial infarction, stroke, peripheral arterial disease, chronic kidney disease and diabetes mellitus. Here, we review the pharmacological properties and established licensed uses of this class of drug, along with emerging therapeutic developments and possible future indications. NO is a cellular signalling molecule implicated in a wide range of regulatory functions, including control of vascular tone, platelet aggregation and cell communication, as well as in the immunological response to infection, chronic inflammation and tumours , inducible NOS (NOS2) and endothelial NOS (NOS3), but can also be derived from the reduction of exogenously administered nitrates  from vascular endothelial cells. Cumulative evidence suggests that the ET pathway opposes the NO–cGMP pathway and contributes to the pathogenesis of several cardiovascular and inflammatory diseases. Pharmacological manipulation of this system via inhibition of ET biosynthesis or direct antagonism of ET receptors has generated significant experimental interest and potential therapeutic applications  to compete with cGMP for access to the PDE5 catalytic site. It was proposed that such an agent could prolong the effects of NO–cGMP signalling in vascular tissue and thus ameliorate conditions associated with NO deficiency, such as angina pectoris. In preclinical studies, the resulting agent — later named 55.1As multiple‐dose Phase I trials of sildenafil for the treatment of angina continued, healthy volunteers began reporting an unexpected and, in hindsight, fortuitous side effect: penile erections. ED, defined as the inability to attain or maintain a penile erection sufficient for successful vaginal intercourse Lue, , had, unThe results from the first clinical study investigating PDE5I treatment in ED were unequivocally positive: Through the inhibition of cGMP degradation in the cavernous smooth muscles, sildenafil enhanced and prolonged the vasodilatory response of cGMP within the corpora cavernosa during sexual stimulation in a dose‐dependent manner to facilitate penile erection, without any safety concerns , the longest acting PDE5I,and vardenafil , the first PDE5I to be available in both film‐coated and oro‐dispersible tablet forms to facilitate adherence in difficult patient groups. This was followed in 2012 by the introduction of avanafil , a more PDE5‐selective agent with favourable tolerability. Alternative PDE5Is have also been licensed in some countries: udenafil is a rapid‐onset but long‐acting agent available in South Korea, Russia and the Philippines  was approved for use in both the United States and the European Union as the first‐line treatment for ED secondary to a broad variety of physical causes  is a disorder characterised by a progressive increase in pulmonary vascular resistance resulting in right heart failure. Five subclasses of PH have been defined (as per the classification of the 6th World Symposium on Pulmonary Hypertension Task Force), among which Group 1 represents PAH, a term which encompasses a number of heterogeneous conditions sharing common pathophysiological, histological and prognostic features  matching as its production is up‐regulated in response to alveolar distension, leading to redirection of blood flow to well‐ventilated areas of the lung —a measure of exercise capacity—and were less likely to die, despite an increase in the incidence of side effects such as headache, flushing, and myalgia , the main Group 4 subtype, by reducing pulmonary artery pressure and improving WHO functional class and 6MWD. Although evidence of mortality benefit is lacking, riociguat is currently recommended as a first‐line therapy in the treatment of CTEPH patients who are unfit for pulmonary endarterectomy . Several studies have demonstrated the safety of PDE5I use in combination with other antihypertensive therapies , which stabilise the membrane potential to allow ATP synthesis and calcium ion transport  and is more successful at reducing attack frequency and promoting ulcer healing than ERAs, an effective and approved treatment for reducing digital ulceration in scleroderma but which has inconsistent or minimal effects on other clinical parameters and is of uncertain benefit in primary RP . RP is a condition characterised by episodic cold‐ or stress‐induced ischaemic vasospastic episodes affecting the digital arteries and arterioles leading to ulcerations and necrosis and is either idiopathic (primary RP) or due to connective tissue disease (secondary RP). A recent meta‐analysis of six RCTs that included 244 patients with secondary RP, predominantly due to scleroderma, found that PDE5I therapy moderately reduced the daily frequency and duration of vasospastic attacks and promoted visible healing of ulcers , which demonstrated a markedly heterogenous response  or angiotensin receptor blocker (ARB) in combination with antihypertensive and antidiabetic medications. Eligible participants had an estimated GFR (eGFR) of 25–59 ml·min−1 per 1.73 m2 (CKD stage G3 or G4) and were randomly assigned to receive either oral PF‐00489791 therapy or placebo once daily for 12 weeks. Remarkably, in the context of treatment‐resistant macroalbuminuria, the PDE5I group demonstrated a significant reduction in albuminuria as early as the third week of therapy. At the end of the 12‐week treatment period, patients receiving PF‐00489791 had a significant, BP‐independent, 16% reduction in UACR compared with placebo. However, this reduction in UACR was reversible and was non‐significant at 16 weeks, 4 weeks after the end of treatment. Although there was no difference in eGFR between treatment and placebo groups throughout the treatment period, this would be unlikely within the short timeframe. Interestingly, there was no initial short‐term fall in eGFR with PDE5I as is usually observed with ACEI/ARB treatment.Although the first clinical trial to evaluate the potential therapeutic benefits of PDE5Is in CKD demonstrated that chronic sildenafil monotherapy significantly reduced microalbuminuria in patients with diabetic nephropathy .These encouraging results suggest that enhancing NO–cGMP signalling confers renoprotective effects and improvements in kidney function, possibly as a result of both haemodynamic and intrarenal anti‐inflammatory, anti‐proliferative and antioxidant mechanisms  is characterised by hyperglycaemia and results from a combination of peripheral insulin resistance and progressive pancreatic β‐cell dysfunction. These pro‐inflammatory states confer higher rates of incident hypertension and cardiovascular risk. Indeed, CVD accounts for two‐thirds of deaths in diabetic patients, with renal sequelae compounding the high rates of morbidity and mortality of this condition , although life course socio‐economic position, compliance and doctor selection practices could not be adjusted for. Significant reductions were also observed in age‐adjusted incidence and mortality rates of acute MI in patients with a history of PDE5I use when compared to subjects never prescribed this class of drug. Notably, ED—the most common indication for PDE5I use—is a strong predictor of subsequent ischaemic heart disease  rise in HbA1c  of 0.3–0.59% from baseline  inhibitors , time to achieve maximum plasma concentration (Tmax) and terminal half‐life , with the latter two having the fastest onset: Vardenafil, in both formulations, acts within 30 min of intake whereas avanafil is the only PDE5I approved for use 15–30 min before sexual intercourse in the treatment of ED. In comparison, mirodenafil and lodenafil have slightly higher Tmax values, with limited published data suggesting that these have a similar onset of action to sildenafil, whereas tadalafil has the highest Tmax, reaching peak plasma concentration after 30–120 min . Tadalafil is uniquely unaffected by dietary intake, enabling once daily dosing such as that required for the management of lower urinary tract symptoms in benign prostatic hyperplasia—an indication for which tadalafil was licensed in 2011 and which is further explored in a recent review  in the liver, chiefly through the CYP3A system with contributions from CYP2C9, CYP2C19, and CYP2D6 pathways , which represents the concentration of the agent that is required to inhibit 50% of PDE5 activity in vitro. Affinity is an inverse measure of potency, such that an agent with a higher IC50 requires a lower dose to reach therapeutic effect. Selectivity refers to the ability of a PDE5I to preferentially bind PDE5 over other PDEs , despite a lack of safety concerns and the former's previously discussed efficacy in hypertension and CKD. Although PF‐03049423 was not found to be effective in improving outcomes following ischaemic stroke , including several antiretroviral protease inhibitors, have been shown to modify the pharmacokinetics of PDE5Is. Whilst coadministration has not been associated with changes in the safety or tolerability of either agent  following use of the agents. NAION, an optic neuropathy precipitated by a decrease in perfusion pressure in the prelaminar region of the optic nerve causing ischaemic infarction and sudden, painless vision loss, is a rare condition, but the leading acquired optic neuropathy in adults over 50 years old, with an annual incidence of 2–10 cases per 100,000 in this population. Several experimental and epidemiological studies have failed to establish a definitive effect of PDE5Is on the ocular circulation or on the risk of NAION . Despite generally promising results in preclinical studies and small clinical trials, in July 2018, the Dutch arm of the international Sildenafil TheRapy In Dismal prognosis Early‐onset fetal growth Restriction (STRIDER) series of RCTs was prematurely terminated after interim data suggested an increased risk of persistent pulmonary hypertension of the newborn (PPHN) and neonatal mortality in the intervention group (Groom, Ganzevoort et al., 8The proven clinical efficacy and excellent safety profile of PDE5Is in the management of ED and PAH has led to their introduction as over‐the‐counter medications as well as prompting significant research interest in the use of these agents for the enhancement of the actions of cGMP in a range of vascular and non‐vascular conditions. In addition to their acute haemodynamic effects, PDE5Is have demonstrated potent anti‐inflammatory, antioxidant, anti‐proliferative and metabolic properties, largely attributable to modulation of the NO–cGMP signalling pathway. A wide array of experimental data suggests a protective effect of PDE5Is in several major organ systems and therapeutic potential in hypertension, chronic kidney disease and diabetes mellitus. In particular, the recent association of long‐term PDE5I treatment with a reduction in all‐cause mortality merits a broader evaluation of PDE5Is. Ultimately, establishing the optimal use and long‐term safety of these agents in CVD will depend on the implementation of larger RCTs, particularly with other comparative treatments, which may be facilitated by the development of novel, longer acting, and more selective PDE5Is.8.1http://www.guidetopharmacology.org, the common portal for data from the IUPHAR/BPS Guide to PHARMACOLOGY (Harding et al., Key protein targets and ligands in this article are hyperlinked to corresponding entries in The authors declare no conflict of interest.


Hepatocellular carcinoma (HCC) is the second leading cause of cancer‐related deaths worldwide. Once considered an experimental treatment with dismal survival rates, liver transplantation for HCC entered a new era with the establishment of the Milan criteria over 20 years ago. In the modern post‐Milan‐criteria era, 5‐year survival outcomes are now upwards of 70% in select patients. Liver transplantation (LT) is now considered the optimal treatment for patients with moderate to severe cirrhosis and HCC, and the rates of transplantation in the United States are continuing to rise. Several expanded selection criteria have been proposed for determining which patients with HCC should be candidates for undergoing LT with similar overall and recurrence‐free survival rates to patients within the Milan criteria. There is also a growing experience with downstaging of patients who fall outside conventional LT criteria at the time of HCC diagnosis with the goal of tumor shrinkage via locoregional therapies to become a candidate for transplantation. The aim of this review article is to characterize the various patient selection criteria for LT, discuss balancing organ stewardship with outcome measures in HCC patients, present evidence on the role of downstaging for large tumors, and explore future directions of LT for HCC. Hepatocellular carcinoma (HCC) is the second leading cause of cancer‐related deaths worldwide. Once considered experimental treatment with dismal survival rates, liver transplantation for HCC entered a new era with the establishment of the Milan criteria over 20 years ago. The aim of this review article is to characterize the various patient selection criteria for liver transplantation, discuss balancing organ stewardship with outcome measures in HCC patients, present evidence on the role of downstaging for large tumors, and explore future directions of liver transplantation for HCC. In 2017, the number of liver transplants performed in the United States was at an all‐time high, with 22% of all liver transplants done for underlying HCC, making HCC the most common indication for LT.Thus, given that LT both removes detectable/undetectable tumors and preneoplastic lesions that are present in the cirrhotic liver, as well as addressing the underlying cirrhotic liver parenchyma, LT is now considered the optimal HCC treatment for patients with advanced (Child‐Pugh B or C) cirrhosis. Better preoperative assessment of liver function, improved accuracy of cross‐sectional imaging studies, and surgical technical progress are key factors that have led to reduced mortality with LT, and 90‐day mortality is currently estimated at around 5%.Although the benefits of LT for patients with HCC are clear, there is ongoing debate surrounding the selection of patients who would be best served by LT and how patients who initially fall outside of recognized criteria for transplant at the time of diagnosis should be managed. The aim of this review is to characterize the various patient selection criteria for LT, discuss balancing organ stewardship with outcome measures in HCC patients, present evidence on the role of downstaging for large tumors, and explore future directions of LT for HCC.2The first liver transplant performed for HCC was completed in 1967 by Thomas Starzl. Due to a lack of guidelines regarding organ allocation in a nascent surgical field, decision making regarding which patients with HCC received liver transplantation was at the discretion of the treatment team. Unfortunately, the lack of recognized organ allocation criteria for HCC patients led to poor outcomes and a temporary moratorium in the United States for liver transplant with HCC acts as an indication of these outcomes. Prior to the global acceptance of organ allocation criteria, the two largest series describing liver transplantation for HCC were published by Bismuth et alIn a report of the European Liver Transplant Registry, Bismuth detailed the results of 32 European centers performing a total of 1218 liver transplants, with over two‐thirds of those cases done after 1984.Iwatsuki et al3The development of the milan criteria (MC), introduced by Mazzaferro et alThe Milan criteria were quickly adopted worldwide, as well as built into a prioritization tool in the United Network of Organ Sharing (UNOS). However, as experience with LT for HCC continued to grow, critics voiced concerns that the Milan criteria may be too restrictive, excluding some patients from undergoing LT who would benefit from transplantation. Critics challenged these criteria, saying they were too strict because they excluded specific subgroups with meaningful, albeit slightly lower, opportunities to benefit from LT, as demonstrated by mostly single‐institution studies.In 2001, Yao et alYao et alWith studies now showing that patients with larger tumors and larger total tumor size were achieving 5‐year survivals similar to patients meeting the Milan criteria, there was an increased interest in exploring the survival of patients with tumors exceeding previously defined limits. Mazzaferro et alIn a departure from “math‐based” to “biology‐based” selection criteria, the extended Toronto criteria were introduced by Dubay et alP = .3; Figure P = .09) with median time to recurrence of 12.8 months. Despite the pretransplant biopsy, 8% of patients exceeding MC had a poorly differentiated tumor at explant pathology. The inclusion of mandatory biopsy in the selection criteria raises some concern due to large variations in the accuracy of tumor grading ranging from 27.5%‐84.8% depending on lesion size and heterogeneitySapisochin et alAs interest grows in the development of biology‐based criteria, multiple new models have been introduced in recent years. The Metroticket 2.0 model, created by Mazzaferro et al,4The Organ Procurement and Transplantation Network (OPTN)/Scientific Registry of Transplant Recipients (SRTR) 2017 Annual Data Report found a continued growth in the number of new waitlist registrants (11 514 in 2017 vs 11 340 in 2016 and 10 636 in 2015) and a continued increase in the transplant rate (51.5 per 100 waitlist‐years).In the USA, starting in 2002, patients with HCC receive priority listing for LT if they have UNOS T2 lesions (single tumor between 2‐5 cm or 2‐3 tumors each ≤3 cm without vascular invasion or extrahepatic spread). This system was developed to give patients with HCC an equal opportunity for transplantation via a “priority Model for End‐Stage Liver Disease (MELD) score” beyond their degree of hepatic decompensation because MELD cannot accurately predict mortality in HCC.Given the extremely limited availability of organs for transplantation in the USA, expansion of selection criteria for LT in HCC must be weighed carefully with regards to the limited supply of organs and the long‐term outcomes of patients undergoing LT for HCC outside of established allocation criteria. In an attempt to determine the optimal benefit of LT for HCC where HCC patients undergoing transplant would not harm patients listed for liver transplant for non‐HCC etiologies, Volk et alP = .21).Patel et alWhile there is conflicting data for expanded criteria outside of UCSF criteria, overall these patients appear to have higher recurrence and lower overall survival. The potential benefit from LT to patients exceeding expanded criteria may be outweighed by potential harms to others on the waitlist. Further higher‐quality, large‐scale studies are needed before expanded criteria can be confidently adopted as standard selection protocol.5Another area of active debate is whether patients with HCC tumors exceeding accepted LT criteria at the time of diagnosis should be “downstaged” using locoregional therapies such as transarterial chemoembolization (TACE) or radiofrequency ablation (RFA) with the goal of decreasing tumor size and selecting patients where liver transplant would provide the most benefit.Yao et alIntention‐to‐treat survival outcomes at 1‐ and 5‐years, respectively, were 86% and 56% in the downstaging group vs 85% and 63% in the T2 group. The 5‐year overall survival was 78% when only those patients who were successfully downstaged were included  or larger (expanded criteria with or without downstaging) HCC lesions might benefit from LT, the benefits to these patients outside the commonly accepted selection criteria need to be balanced against the harms to other patients waiting for liver transplants given the limited availability of donors.Funding: No sources of funding were received.Conflict of Interest: Authors declare no conflict of interest for this article.Author Contribution: MRJ and ACY contributed equally to the preparation of this manuscript.