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Common variable immunodeficiency syndrome (CVID) includes a heterogeneous disorder characterized by reduced levels of IgG, IgA or IgM, and recurrent bacterial infections with normal T-cell immunity in 60% of patients. It affects the gastrointestinal tract as the largest immune organ with a wide spectrum of symptoms and signs. We present a case of nodular lymphoid hyperplasia (NLH) of the small intestine in a 31-year-old man admitted for evaluation of chronic diarrhea. Upper and lower gastrointestinal endoscopy revealed multiple polyps in the stomach, duodenum, ileum, and large intestine mimicking familial adenomatous polyposis (FAP). Although he had no history of recurrent infection, immunological profiles were in favor of CVID. We emphasize the importance of considering CVID in any patient with gastrointestinal manifestations even in the absence of recurrent bacterial infections. Diagnostic delay results in more morbidity and complications in untreated patients.

Interval-training activities induce adaptive cellular changes without altering their fundamental identity, but the precise underlying molecular mechanisms are not fully understood. In this study, we demonstrate that interval-training depolarization (ITD) of pituitary cells triggers distinct adaptive or homeostatic splicing responses of alternative exons. This occurs while preserving the steady-state expression of the Prolactin and other hormone genes. The nature of these splicing responses depends on the exon's DNA methylation status, the methyl-C-binding protein MeCP2 and its associated CA-rich motif-binding hnRNP L. Interestingly, the steady expression of the Prolactin gene is also reliant on MeCP2, whose disruption leads to exacerbated multi-exon aberrant splicing and overexpression of the hormone gene transcripts upon ITD, similar to the observed hyperprolactinemia or activity-dependent aberrant splicing in Rett Syndrome. Therefore, epigenetic control is crucial for both adaptive and homeostatic splicing and particularly the steady expression of the Prolactin hormone gene during ITD. Disruption in this regulation may have significant implications for the development of progressive diseases., (© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Alzheimer's disease (AD) is a progressive neurological condition characterized by impaired cognitive function and behavioral alterations. While AD research historically centered around mis-folded proteins, advances in mass spectrometry techniques have triggered increased exploration of the AD lipidome with lipid dysregulation emerging as a critical player in AD pathogenesis. Gangliosides are a class of glycosphingolipids enriched within the central nervous system. Previous work has suggested a shift in a-series gangliosides from complex (GM1) to simple (GM2 and GM3) species may be related to the development of neurodegenerative disease. In addition, complex gangliosides with 20 carbon sphingosine chains have been shown to increase in the aging brain. In this study, we utilized matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) to interrogate the in situ relationship of a-series gangliosides with either 18 or 20 carbon sphingosine chains (d18:1 or d20:1, respectively) in the post-mortem human AD brain. Here, we expanded upon previous literature and demonstrated a significant decrease in the GM1 d20:1 to GM1 d18:1 ratio in regions of the dentate gyrus and entorhinal cortex in AD relative to control brain tissue. Then, we demonstrated that the MALDI-MSI profile of GM3 co-localizes with histologically confirmed amyloid beta (Aβ) plaques and found a significant increase in both GM1 and GM3 in proximity to Aβ plaques. Collectively, this study demonstrates a perturbation of the ganglioside profile in AD, and validates a pipeline for MALDI-MSI and classic histological staining in the same tissue sections. This demonstrates feasibility for integrating untargeted mass spectrometry imaging approaches into a digital pathology framework., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: STAT3 hyperimmunoglobulin E syndrome (STAT3-HIES) also referred to as autosomal dominant HIES (AD-HIES) is an inborn error of immunity characterized by the classic triad of eczema, frequent opportunistic infections, and elevated serum IgE levels. As a consequence of lung sequels due to repeated infections and impaired tissue healing, patients may require interventional pulmonary procedures., Method: Four patients with dominant-negative STAT3 mutations who had received interventional pulmonary procedures were enrolled. The demographic, clinical, and molecular characteristics were gathered through a medical record search. All reported STAT3-HIES patients in the literature requiring pulmonary procedures as part of their treatment were reviewed., Result: Recurrent episodes of pneumonia and lung abscess were the most prevalent symptoms. The most common non-immunological features were scoliosis, failure to thrive, and dental problems such as primary teeth retention and disseminated decays. Bronchiectasis, lung abscess, pneumatocele, and cavitary lesion were the most prevalent finding on high-resolution computed tomography at the earliest recording. All patients underwent pulmonary surgery and two of them experienced complications., Conclusion: Patients with STAT3-HIES have marked pulmonary infection susceptibility which may necessitate thoracic surgeries. Since surgical procedures involve a high risk of complication, surgical options are recommended to be utilized only in cases of drug resistance or emergencies., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Primary dural Hodgkin lymphoma (PDHL) is an extremely rare subset of Hodgkin lymphoma (HL). Its existence is controversial, as Hodgkin lymphoma is not traditionally thought to arise from the central nervous system (CNS) or its meninges and only 0.02% of patients with Hodgkin lymphoma have any CNS involvement. We report a case of a 71-year-old Caucasian man who presented with progressive fatigue and sudden onset slurred speech, disorientation, and memory loss. Brain imaging identified a large extra-axial right frontal mass, and he underwent urgent subtotal resection. Pathology and subsequent workup revealed Stage IAE classical Hodgkin lymphoma of the right frontal dura, with no extra-cranial disease or leptomeningeal spread detected. The patient was subsequently treated with ABVD chemotherapy (completed 2.5 of 4 planned cycles) and 36 Gy in 20 fractions of consolidative involved-site radiotherapy (ISRT). He has been followed for 5 years with no clinical or radiological signs of recurrence. This is the second confirmed case of intracranial PDHL reported in the literature, with the longest follow-up for any case of PDHL., (© 2023 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd.)

The COVID-19 pandemic has had a significant impact on medical services. Many countries postponed nonemergent procedures to preserve hospital resources for the unprecedented situation. Surgical backlogs caused by the COVID-19 pandemic have been evaluated by different groups. However, the impact of this pandemic on pathology and specifically neuropathology (NP) services has received limited attention. In this study, we reviewed all NP reports of the London Health Sciences Centre from January 2018 (2 years before the pandemic declaration) until the end of the year 2021. Demographic information and pathology details were collected. For tumors, site, histopathology types, and WHO grading were analyzed. In nontumoral specimens, pathological diagnoses were compared in pre- and postpandemic time. The total number of NP samples reached its lowest in April 2020, corresponding to the first Ontario provincial lockdown, and fluctuated throughout the studied period. Among the different types of NP surgical specimens, muscle and epilepsy-related specimens showed a more significant reduction, compared to neoplastic specimens. In 2020, the proportion of tumor specimens from patients older than 40 years of age increased. Similarly, the proportion of high-grade glioma and brain metastasis diagnoses also increased. Lastly, we observed a marked increase in biopsies for temporal arteritis and other inflammatory lesions., (© The Author(s) 2023. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Hydatidosis is one of the most critical worldwide parasitic zoonotic diseases. The lung is the second most common site of hydatidosis. This study aimed to evaluate the clinical status, diagnosis, treatment, and radiological findings of pulmonary hydatid cyst in patients referred to tertiary lung center., Methods: From April 2014 to July 2019, patients referred to Masih Daneshvari University Medical Center with the impression of alveolar hydatidosis included. Demographic data of 304 patients were collected including clinical symptoms, laboratory studies, radiological findings, location of the lung involvement, and cyst characteristics. Also, surgical procedures, medical treatments, and post-operative complications were recorded., Results: Pulmonary hydatidosis was confirmed for 234 patients. 55% of patients were males with the mean age of 45.1±16.6 years. The most common symptoms were cough (59.8%), dyspnea (31.1%), and hemoptysis (26%). Left lung, right lung, and bilateral involvement were reported in 40.1%, 55.1%, and 4.8% of cases, respectively. Cyst perforation (39.8%) was the most common intra-operative finding. Surgical interventions included thoracotomy, rigid bronchoscopy, cyst aspiration, and enucleation. The liver was the most concomitant organ involved due to pulmonary hydatidosis (16.6%). The most common postoperative complication was atelectasis, with the rate of 35.7%. 52.2% of patients were discharged within 10 days after surgery. No mortality was reported., Conclusion: Sometimes atypical findings in different imaging modalities make the hydatid cyst diagnosis challenging. Although lobe involvement more than 50% has the indication for lobectomy, we conserved lobes with about 70% involvement in our institution, and patients had no postoperative complications., Competing Interests: The authors declare that they have no conflicts of interests.

Background: Lung cancer has recently shown the highest incidence among all cancers. microRNAs (miRNAs) are the molecules playing a role in regulating gene expression and contributing to many pathogenic mechanisms. Therefore, these molecules could be used as biomarkers for the detection, anticipation, and treatment of cancer. With this in mind, we decided to investigate and compare the expression of miR-1, miR-133, miR-191, and miR-24 and also the expression differences in these four RNA molecules between lung cancer patients and the controls., Methods: A total of 50 patients with lung cancer participated in this study. In addition, 50 healthy blood samples were selected as the control group. Real-time PCR determined the expression levels of miRNA. The RNAs extracted from the patients' white blood cells were initially synthesized, and then cDNA was extracted. Finally, the synthesized cDNA was amplified using real-time PCR, and its expression was compared with the control group., Results: The result indicated a low expression level of miR-1 and miR-133, and a high expression level of miR-191 and miR-24 in the blood of patients with lung cancer compared to the healthy subjects., Conclusion: Our findings revealed that miR-1, miR-133, miR-191, and miR-24 are oncogenes, and their expression could result in cancer. It appears that a therapy to overexpress miR-1 and miR-133 and downexpress miR-191 and miR-24 could contribute to the treatment of lung cancer.

Eukaryotic gene expression is controlled at multiple levels, including gene transcription and protein translation initiation. One molecule with key roles in both regulatory mechanisms is methyl CpG binding protein 2 (MeCP2). MECP2 gain- and loss-of-function mutations lead to Rett Syndrome and MECP2 Duplication Syndrome, respectively. To study MECP2 gain-of-function, we generated stably transduced human brain cells using lentiviral vectors for both MECP2E1 and MECP2E2 isoforms. Stable overexpression was confirmed by Western blot and immunofluorescence. We assessed the impact of MeCP2E1-E2 gain-of-function on the MeCP2 homeostasis regulatory network ( MECP2E1/E2-BDNF /BDNF- miR-132 ), mTOR-AKT signaling, ribosome biogenesis, markers of chromatin structure, and protein translation initiation. We observed that combined co-transduction of MeCP2 isoforms led to protein degradation of MeCP2E1. Proteosome inhibition by MG132 treatment recovered MeCP2E1 protein within an hour, suggesting its induced degradation through the proteosome pathway. No significant change was detected for translation initiation factors as a result of MeCP2E1, MeCP2E2, or combined overexpression of both isoforms. In contrast, analysis of human Rett Syndrome brains tissues compared with controls indicated impaired protein translation initiation, suggesting that such mechanisms may have differential sensitivity to MECP2 gain- and loss-of-function. Collectively, our results provide further insight towards the dose-dependent functional role of MeCP2 isoforms in the human brain.

Background: Management of multisegmental tracheal stenosis is challenging. In this 24-year longitudinal single-center study, we present an algorithmic treatment approach., Methods: A retrospective analysis of 2167 patients with postintubation tracheal stenosis indicated 83 (3.83%) patients with multisegmental tracheal stenosis. Patients were assigned to 4 management groups according to the length, location, and severity of stenoses; tracheal infection/mucositis; laryngeal function; symptoms; general condition; and comorbid diseases. Type 1 (n = 13): 1-stage resection of both strictures, Type 2 (n = 6): 2-stage resection of both strictures, Type 3 (n = 40): resection of 1 stricture and nonresectional management of the other, Type 4 (n = 24): nonresectional management of both strictures. Outcomes were categorized as Good, Acceptable, or Poor. Univariate analyses for factors predictive of recurrence and outcome were performed., Results: Follow-ups were completed in 70 (84.34%) patients (median, 22.5 months). Outcome was assessed as Good in 56 (82.35%), Acceptable in 10 (14.71%), Poor in 2 (2.94%), and mortality in 2 (2.94%) patients. The median length of airway resection was 46, 67.5, and 40 mm in Types 1-3, respectively. Only 11 (13.25%) patients had no history of tracheostomy or tracheal surgery. By univariate analysis, a shorter intubation period was associated with Good outcome (P = .017). No factors predictive of recurrence or outcome were ascertained., Conclusions: Multisegmental tracheal stenosis, generally caused by performing an inappropriate tracheostomy, is an iatrogenic disease that can be prevented. Although resection of both strictures may be feasible and is associated with Good results, in the majority of cases, a combination of surgical resection and non-resectional methods are sufficient to achieve Good results., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

The significance of commuting with ebikes as an integral part of the urban mobility of the future can no longer be ignored. The real and perceived hazards of cycling in urban areas and sharing roads with other motorized vehicles have been identified as a major barrier to wider adoption of ebikes. The objective of this study is to investigate parameters that affect the anxiety level of cyclists, which influences their safety and interaction with other road users. An ebike was instrumented with a variety of sensors and equipment to monitor the speed, balance of bike, type, and proximity of vehicles overtaking cyclists, as well as the events on the road. Thirty-two participants rode the instrumented ebike for 12 km on urban roads in Oshawa, ON, Canada. Participants wore a heart rate sensor attached to their chest and a helmet equipped with a peripheral detection task setup to measure stress and mental workload. This naturalistic study showed that most participants had concerns about the threats and risks of crashes when sharing the road with other vehicles. The data showed that the significant difference in acceleration between ebikes and conventional bikes does not change the perception of safety for cyclists. Additionally, the outcomes indicate that mental workload and average heart rate increase at lower speeds when passing a queue of vehicles in traffic or at intersections. Across all participants, the balance of the bike did not change significantly. Also, neither the heart rate nor mental workload showed a significant effect on the balance of the bike. This study suggests that dense traffic in the afternoon and the demands of riding a bike in complex traffic conditions result in a higher mental workload even though cyclists slowed down their speeds. Furthermore, the majority reported perceived risks of cycling on a shared road with other vehicles regardless of the demographic differences. The findings from this study can be used as a framework for the development of active safety features for ebikes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Rett Syndrome (RTT) is a severe, rare, and progressive developmental disorder with patients displaying neurological regression and autism spectrum features. The affected individuals are primarily young females, and more than 95% of patients carry de novo mutation(s) in the Methyl-CpG-Binding Protein 2 ( MECP2) gene. While the majority of RTT patients have MECP2 mutations (classical RTT), a small fraction of the patients (atypical RTT) may carry genetic mutations in other genes such as the cyclin-dependent kinase-like 5 ( CDKL5) and FOXG1 . Due to the neurological basis of RTT symptoms, MeCP2 function was originally studied in nerve cells (neurons). However, later research highlighted its importance in other cell types of the brain including glia. In this regard, scientists benefitted from modeling the disease using many different cellular systems and transgenic mice with loss- or gain-of-function mutations. Additionally, limited research in human postmortem brain tissues provided invaluable findings in RTT pathobiology and disease mechanism. MeCP2 expression in the brain is tightly regulated, and its altered expression leads to abnormal brain function, implicating MeCP2 in some cases of autism spectrum disorders. In certain disease conditions, MeCP2 homeostasis control is impaired, the regulation of which in rodents involves a regulatory microRNA ( miR132 ) and brain-derived neurotrophic factor (BDNF). Here, we will provide an overview of recent advances in understanding the underlying mechanism of disease in RTT and the associated genetic mutations in the MECP2 gene along with the pathobiology of the disease, the role of the two most studied protein variants (MeCP2E1 and MeCP2E2 isoforms), and the regulatory mechanisms that control MeCP2 homeostasis network in the brain, including BDNF and miR132 .

Rett Syndrome (RTT) is a rare and progressive neurodevelopmental disorder that is caused by de novo mutations in the X-linked Methyl CpG binding protein 2 ( MECP2 ) gene and is subjected to X-chromosome inactivation. RTT is commonly associated with neurological regression, autistic features, motor control impairment, seizures, loss of speech and purposeful hand movements, mainly affecting females. Different animal and cellular model systems have tremendously contributed to our current knowledge about MeCP2 and RTT. However, the majority of these findings remain unexamined in the brain of RTT patients. Based on previous studies in rodent brains, the highly conserved neuronal microRNA " miR132 " was suggested to be an inhibitor of MeCP2 expression. The neuronal miR132 itself is induced by Brain Derived Neurotrophic Factor (BDNF), a neurotransmitter modulator, which in turn is controlled by MeCP2. This makes the basis of the MECP2-BDNF-miR132 feedback regulatory loop in the brain. Here, we studied the components of this feedback regulatory network in humans, and its possible impairment in the brain of RTT patients. In this regard, we evaluated the transcript and protein levels of MECP2 /MeCP2E1 and E2 isoforms, BDNF /BDNF, and miR132 (both 3p and 5p strands) by real time RT-PCR, Western blot, and ELISA in four different regions of the human RTT brains and their age-, post-mortem delay-, and sex-matched controls. The transcript level of the studied elements was significantly compromised in RTT patients, even though the change was not identical in different parts of the brain. Our data indicates that MeCP2E1/E2-BDNF protein levels did not follow their corresponding transcript trends. Correlational studies suggested that the MECP2E1/E2-BDNF-miR132 homeostasis regulation might not be similarly controlled in different parts of the human brain. Despite challenges in evaluating autopsy samples in rare diseases, our findings would help to shed some light on RTT pathobiology, and obscurities caused by limited studies on MeCP2 regulation in the human brain., (Copyright © 2020 Pejhan, Del Bigio and Rastegar.)

Background: Neurenteric cysts are rare lesions that typically present in the upper thoracic and cervical spine and are occasionally found intracranially. The optimal treatment is gross total excision as subtotal/partial excisions are associated with high recurrence rates., Case Description: For the past 10 years, a patient with pseudotumor cerebri required repeated lumboperitoneal (LP) shunt revisions. This resulted in multiple neuroenterogenous cysts occurring around the proximal LP subarachnoid shunt catheter, a finding likely attributable to retrograde flow from the peritoneal cavity., Conclusion: Unlike ventriculoperitoneal (VP) shunts and LP shunts do not contain valves, making the retrograde passage of enterogenous cells possible when abdominal pressure exceeds lumbar subarachnoid pressure, especially in the morbidly obese patient., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Surgical Neurology International.)

Background: Deep knee bending has been reported as an occupational hazard to workers who have to adopt such postures. High knee joint moments have been associated with knee osteoarthritis initiation and progression., Objective: This study aimed to compare four high knee flexion postures (dorsiflexed and plantarflexed kneeling, and flat-foot and heels-up squatting) to determine which one results in lower knee joint flexion and ab/adduction moments., Methods: Forty-three participants performed five trials of each posture. Peak (for descent/ascent) and mean (for the static hold) external knee flexion and ab/adduction moments were analyzed for each posture using 2-way ANOVAs and post-hoc pairwise comparisons., Results: It was observed that the flat-foot squat resulted in significantly lower knee flexion moment compared to the other three postures (4.63±0.99 % BW·H during the static phase, and 5.83±1.24 % BW·H and 5.94±1.24 % BW·H during descent and ascent phases, respectively). During ascent phase, significant differences was indicated in peak adduction moments for the flat-foot squat in comparison to both styles of kneeling., Conclusions: When high knee flexion is required but posture is not dictated, flat-foot squat will reduce exposures to high knee moments.

Workers who kneel or squat frequently are at a high risk of developing knee pathologies. Knee Savers ® are wedge-shaped pads, worn on the lower calf by baseball catchers that aim to reduce this risk. This study examined how Knee Savers ® change the bilateral quadriceps muscle activity during dorsiflexed kneeling, and heels-up and flat-foot squatting. For twenty participants, integrated and peak electromyography (EMG) during descent and ascent phases, mean EMG during a 10-s static phase, and participants' subjective perception of muscle fatigue were compared between equipment conditions (with (W) and without (WO) Knee Savers ® ). Knee Savers ® did not significantly reduce integrated or peak EMG during transitions into and out of the postures; however, they significantly reduced (p < .03) mean EMG in five of six muscles during the static phase. These findings indicate potential for Knee Savers ® to reduce cumulative muscular effort and fatigue in applications where prolonged static kneeling or squatting are required., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Rett syndrome (RTT) is a severe and rare neurological disorder that is caused by mutations in the X-linked MECP2 (methyl CpG-binding protein 2) gene. MeCP2 protein is an important epigenetic factor in the brain and in neurons. In Mecp2 -deficient neurons, nucleoli structures are compromised. Nucleoli are sites of active ribosomal RNA ( rRNA ) transcription and maturation, a process mainly controlled by nucleolin and mechanistic target of rapamycin (mTOR)-P70S6K signaling. Currently, it is unclear how nucleolin- rRNA -mTOR-P70S6K signaling from RTT cellular model systems translates into human RTT brain. Here, we studied the components of nucleolin- rRNA -mTOR-P70S6K signaling in the brain of RTT patients with common T158M and R255X mutations. Immunohistochemical examination of T158M brain showed disturbed nucleolin subcellular localization, which was absent in Mecp2 -deficient homozygous male or heterozygote female mice, compared to wild type (WT). We confirmed by Western blot analysis that nucleolin protein levels are altered in RTT brain, but not in Mecp2 -deficient mice. Further, we studied the expression of rRNA transcripts in Mecp2 -deficient mice and RTT patients, as downstream molecules that are controlled by nucleolin. By data mining of published ChIP-seq studies, we showed MeCP2-binding at the multi-copy rRNA genes in the mouse brain, suggesting that rRNA might be a direct MeCP2 target gene. Additionally, we observed compromised mTOR-P70S6K signaling in the human RTT brain, a molecular pathway that is upstream of rRNA -nucleolin molecular conduits. RTT patients showed significantly higher phosphorylation of active mTORC1 or mTORC2 complexes compared to age- and sex-matched controls. Correlational analysis of mTORC1/2-P70S6K signaling pathway identified multiple points of deviation from the control tissues that may result in abnormal ribosome biogenesis in RTT brain. To our knowledge, this is the first report of deregulated nucleolin- rRNA -mTOR-P70S6K signaling in the human RTT brain. Our results provide important insight toward understanding the molecular properties of human RTT brain.

Most authors believe that the optimal treatment for pulmonary hydatid cyst is surgery. Albendazole has been used as a prophylactic measure for reducing recurrence rate but there are some controversies about this strategy. Some researchers have described the increased risk of spontaneous rupture of cysts following albendazole treatment. In this case report, we present a case of spontaneous rupture of pulmonary hydatid cyst with fatal outcome that may be the adverse cause of albendazole., Competing Interests: Conflict of Interest There is no conflict of interest to declare.

Contact pressure and stresses on the articulating surface of the tibial component of a total knee replacement are directly related to the joint contact forces and the contact area. These stresses can result in wear and fatigue damage of the ultra-high-molecular-weight polyethylene. Therefore, conducting stress analysis on a newly designed surface-guided knee implant is necessary to evaluate the design with respect to the polyethylene wear. Finite element modeling is used to analyze the design's performance in level walking, stair ascending and squatting. Two different constitutive material models have been used for the tibia component to evaluate the effect of material properties on the stress distribution. The contact pressure results of the finite element analysis are compared with the results of contact pressure using pressure-sensitive film tests. In both analyses, the average contact pressure remains below the material limits of ultra-high-molecular-weight polyethylene insert. The peak von Mises stresses in 90° of flexion and 120° of flexion (squatting) are 16.28 and 29.55 MPa, respectively. All the peak stresses are less than the fatigue failure limit of ultra-high-molecular-weight polyethylene which is 32 MPa. The average contact pressure during 90° and 120° of flexion in squatting are 5.51 and 5.46 MPa according to finite element analysis and 5.67 and 8.14 MPa according to pressure-sensitive film experiment. Surface-guided knee implants are aimed to resolve the limitations in activities of daily living after total knee replacement by providing close to normal kinematics. The proposed knee implant model provides patterns of motion much closer to the natural target, especially as the knee flexes to higher degrees during squatting.

Different designs of total knee replacements (TKRs) aim to enhance the satisfaction of the patients by providing close to normal kinematics. In the surface-guided TKRs, the guidance of the motion in a normal pattern should be achieved through specially shaped articulating geometries. This study used virtual simulation along with a load-controlled knee wear simulator to evaluate the kinematic performance of a customized surface-guided TKR under weight-bearing conditions of lunging and squatting activities. The outcome pattern of TKR motion almost agreed with the predefined design target. The tibial insert rotated internally through a maximum angle of 10.6° and 19.94° for the experimentally simulated lunging and squatting cycles, respectively. This rotation occurred around a medial center, as indicated by a small amount of posterior translation of the medial condyle (maximum of 2.5mm and 6.4mm for lunging and squatting) versus the posterior translation of the lateral condyle (maximum of 12mm and 24.2mm for lunging and squatting). The contact forces mainly provided the guidance of the motion at the tibiofemoral articulating surfaces.The normalized root mean square error between outcomes of the virtual simulations and tests for the angle of internal-external rotation of the tibial insert was less than 8% for one cycle of lunging and squatting. These measures confirm the validity of the virtual simulation for future evaluations of the customized surface-guided TKRs., (Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.)

Objective: Tibiofemoral geometries in a total knee replacement (TKR) affect the performance of an implant during activities of daily living. The specially shaped components of a surface-guided TKR aim to control the tibiofemoral motion, such that a normal pattern of motion is achieved, even at high flexion angles. The purpose of this study was to assess the influence of the design parameters on the kinematic behavior of such an implant. A combination of design variables was determined that resulted in the least deviation from the design kinematic target., Methods: Six major design variables were considered to generate customized surface-guided TKR candidates. The contribution of these variables was evaluated by principal component analysis considering the input design variables and the results of the kinematic performance from a virtual simulation of deep squatting. The tibial internal-external rotation and the anterior-posterior translation of the medial and lateral femoral condyles were recorded for each design candidate. A quantified objective function of the kinematic behavior was used to define the design with a maximum agreement with the target pattern of motion., Results: The location and orientation of the flexion-extension axis and the tibial slope were the most contributing parameters on the modes of variation. On the other hand, the conformity between the lateral guiding arcs had the least contribution., Conclusion: Virtual simulation showed that the current TKR reached deep flexion angles under squat load, while the tibia pivoted around the medial center. The tibial rotation was within the expected range of the IE rotation from healthy joints.

Background: Most patients with postintubation tracheal stenosis are not ideal candidates for airway resection at presentation and their airways must be temporarily kept open by repeated bronchoscopic dilation (RBD). Meanwhile, some sufficiently recover by RBD without further airway resection requirement. We hypothesized whether systemic corticosteroids could lengthen RBD intervals, decrease the number of patients who eventually need airway resection, and shorten the required length of airway resection., Methods: Between February 2009 and November 2012, a randomized double-blind clinical trial with a 1:1 ratio (corticosteroids group [group C], prednisolone 15 mg/day; placebo group [group P]) was conducted on 120 patients without tracheostomy or T tube and in no ideal situation for airway resection at presentation, whose precipitating injury had occurred recently. All underwent RBD until they became asymptomatic or prepared for airway resection. Asymptomatic patients received the capsules (prednisolone or placebo) for 6 months; others discontinued them before surgery. Those requiring RBD at short intervals underwent tracheostomy or T tube placement and were then excluded. Follow-up terminated 6 months after airway resection or capsule discontinuation., Results: There were 105 patients (72 male; 50 in group C), aged 15 to 64 years, who completed their follow-up. There was no significant difference between the two groups in age, sex, history of tracheostomy, intubation cause and duration, time interval between intubation and initial bronchoscopy, length of stenosis, and subglottic involvement. Our study showed a trend for RBD with longer intervals (22 days), and fewer operations, 17% (28 of 50 versus 40 of 55) in group C, although statistically insignificant. Furthermore, the required airway resection length became significantly shorter (5.3 mm) in group C., Conclusions: Early low-dose systemic corticosteroids can be beneficial in postintubation tracheal stenosis management., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Although total knee arthroplasty is generally a successful operation, many studies have shown that it results in significant alterations in the kinematics of the joint, which cause limitations in performing the activities of daily living. This study aimed to define the design features for a customized surface-guided total knee replacement and to evaluate the kinematic outcomes. Magnetic resonance imaging data of the knee joint are used to generate the design features as they relate to the functionality of the implant. The motion is guided by considering a partial ball and socket configuration on the medial condyle and varying radii of curvature on the lateral articulating surface. A virtual simulation of the behavior of the surface-guided total knee replacement was performed to investigate the motion patterns of this total knee replacement under gait and squatting loading conditions. Results of the virtual simulation show that flexion and extension of the knee make the center of the lateral condyle move more naturally in the posterior and anterior directions, in comparison to the center of the medial condyle. Such guidance is achieved as a result of the novel customized designed contact between the articulating surfaces. The proposed customized surface-guided total knee replacement provides patterns of motion close to the expected more natural target, not only during a gait cycle but also as the knee flexes to higher degrees during squatting. Major design features include location and orientation of the flexion and pivoting axes, the trace of the contact points on the tibia, and the radii of the guiding arcs on the lateral condyle., (© IMechE 2016.)

Background: Surgery is an appropriate therapeutic approach for tracheal stenosis due to various benign and malignant conditions. When surgery is postponed for certain reasons, other options are chosen for airway patency. One alternative is using airway stents., Objectives: We aimed to introduce a safe method of tracheal polyflex stent placement in patients with tracheal stenoses., Patients and Methods: During a 7-year period (2002 - 2008), polyflex stents were used 29 times among 20 patients for various indications. After encountering many difficulties in earlier cases, we gradually developed our new method and used it in most of our patients. In this method, without using large rigid bronchoscopes, the introducer tube could be used as a bronchoscope with the aid of a zero-degree lens and ventilating apparatus. In this method, the rate of possible trauma to the airway can be minimized by avoiding the use of thick rigid bronchoscopies and the stent can be placed faster and more accurately., Results: Polyflex stents were used in 11 men (55%) and 9 women with a mean age of 38.5 years. Stents were removed and changed in 12 cases and replaced with another type of stent in 3 patients. Indications were recurrence of tracheal stenosis (7), multisegmental tracheal stenosis (3), anesthesia limitations (3), tracheal tumors (2), dehiscence of tracheal anastomosis (1), severe inflammation of the tracheal mucosa (1), esophagobronchial fistula (1), and external pressure on the left main bronchus (1). In one patient, a stent was used to open a kinked Dumon stent as a temporary life-saving procedure. We found 6 cases of stent migration, 3 cases of granulation tissue formation, 1 case of infection, and 1 case of surgical site dehiscence., Conclusions: Stents would be regarded as a temporary means of reaching the ideal condition for resection and reconstruction in most patients with tracheal stenoses. Although an optimal stent has not been introduced yet, we used polyflex stents in most of our patients with tracheal stenosis due to its availability and ease of use. We suggest that this method is safe and less time consuming than its traditional method of placement.

Purpose: In this study we present the clinical, radiological, pathological, bronchoscopic and surgical results of 40 patients with diagnosis of middle lobe syndrome who were referred to our thoracic surgery unit for surgical intervention in a 10 years period., Methods: Forty patients with obstructive and non-obstructive causes of middle lobe syndrome referred to our thoracic surgery unit. Clinical data were collected from the patients' records in a ten years period. This study evaluates diagnostic approaches and surgical treatments in right middle lobe syndrome., Results: We studied 23 females (57.5%) and 17 males (42.5%) with a mean age of 31.7. Clinical findings were cough 95%, sputum 80% and intermittent hemoptysis in 50% of patients. Middle lobe collapse was seen in CT scan of all patients. Bronchiectasis was the most common pathologic finding (55%). Tuberculosis was not rare and was final pathology in 20% of patients. In three patients ruptured hydatid cyst was final finding. Surgery was done without mortality and with only minor complications., Conclusion: Lobectomy of right middle lobe is a good therapeutic option in these patients. Due to high prevalence of tuberculosis and hydatid cyst in Middle Eastern countries these two must be considered as causes of middle lobe syndrome.

Introduction: Gorham's disease is a rare disorder characterized by osteolysis and abnormal vascular growth within bones. Diagnosis of Gorham's disease is often delayed and for accurate and early diagnosis high clinical suspicion is crucial. No specific treatment is available. Management options include surgery, radiation therapy and medical therapy. We aimed to present the first case of Gorham's disease with chest wall involvement in Iran. By review of the literature we discussed important issues of this rare disease including clinical findings, diagnosis and treatment options., Case Presentation: We present a 48-year-old man with a history of dyspnea following a blunt chest trauma who was admitted to our clinic several times due to reaccumulation of pleural fluid and chylothorax. Gorham's disease was finally established according to clinical manifestations and radiological findings including massive osteolysis in his left ribs and also histological examination., Discussion: According to review of the literature and considering all treatment modalities the patients was successfully treated with a combination of radiotherapy, pamidronate and thalidomide. We suggest that this disease should be considered among differential diagnoses of patients with chest pain, pleural effusion and/or chylothorax with an unknown reason and more importantly history of chest trauma. In suspected cases, it is essential to examine biopsy specimens of the bone adjacent to the inflammated tissues in order to confirm diagnosis.