The mechanobiological theory: a unifying hypothesis on the pathogenesis of moyamoya disease based on a systematic review

OBJECTIVE Moyamoya angiopathy (MMA) affects the distal internal carotid artery and is designated as moyamoya disease (MMD) when predisposing conditions are absent, or moyamoya syndrome (MMS) when it occurs secondary to other causes. The authors aimed to investigate the reason for this anatomical site predilection of MMA. There is compelling evidence to suggest that MMA is a phenomenon that occurs due to stereotyped mechanobiological processes. Literature regarding MMD and MMS was systematically reviewed to decipher a common pattern relating to the development of MMA. METHODS A systematic review was conducted to understand the pathogenesis of MMA in accordance with PRISMA guidelines. PubMed MEDLINE and Scopus were searched using “moyamoya” and “pathogenesis” as common keywords and specific keywords related to six identified key factors. Additionally, a literature search was performed for MMS using “moyamoya” and “pathogenesis” combined with reported associations. A progressive search of the literature was also performed using the keywords “matrix metalloprotease,” “tissue inhibitor of matrix metalloprotease,” “endothelial cell,” “smooth muscle cell,” “cytokines,” “endothelin,” and “transforming growth factor” to infer the missing links in molecular pathogenesis of MMA. Studies conforming to the inclusion criteria were reviewed. RESULTS The literature search yielded 44 published articles on MMD by using keywords classified under the six key factors, namely arterial tortuosity, vascular angles, wall shear stress, molecular factors, blood rheology/viscosity, and blood vessel wall strength, and 477 published articles on MMS associations. Information obtained from 51 articles that matched the inclusion criteria and additional information derived from the progressive search mentioned above were used to connect the key factors to derive a network pattern of pathogenesis. CONCLUSIONS Based on the available literature, the authors have proposed a unifying theory for the pathogenesis of MMA. The moyamoya phenomenon appears to be the culmination of an interplay of vascular anatomy, hemodynamics, rheology, blood vessel wall strength, and a plethora of intricately linked mechanobiological molecular mediators that ultimately results in the mechanical process of occlusion of the blood vessel, stimulating angiogenesis and collateral blood supply in an attempt to perfuse the compromised brain.

Causes and Management of Uterine Perforation- A Review

Uterine perforation is an intrauterine problem that can occur with any therapy. It is a rare but possibly dangerous consequence of uterine manipulation, evacuation of retained products of conception or pregnancy termination (TOP), hysteroscopic treatments, and coil implantation. Injury to blood arteries or viscera, such as the bladder or the intestine, might be related. Severe bleeding or infection may ensue if not discovered at the time of surgery; nevertheless, the most majority of uterine drilling is subclinical and safe without treatment, with no substantial long-term damage. Perforation can be caused by cervical stenosis during trans-cervical operations or by a reduction in myometrial wall strength during pregnancy or menopause. Uterine abnormalities, infection, recent pregnancy, and postmenopause are all factors that raise the chance of uterine perforation. The treatment of uterine perforation is determined by the operation and the equipment employed. Admission to the hospital, intravenous antibiotics, and close supervision are required following a uterine perforation and any accompanying injuries. In this paper, we overview common causes and updated management of uterine perforation. Data was collected during a period of 6 months searching Pubmed, EPISCO, Web of science data bases to include studies with relative topics.

Tomato transcriptomic response to Tuta absoluta infestation

Background The South America pinworm, Tuta absoluta, is a destructive pest of tomato that causes important losses worldwide. Breeding of resistant/tolerant tomato cultivars could be an effective strategy for T. absoluta management but, despite the economic importance of tomato, very limited information is available about its response to this treat. To elucidate the defense mechanisms to herbivore feeding a comparative analysis was performed between a tolerant and susceptible cultivated tomato at both morphological and transcriptome level to highlight constitutive leaf barriers, molecular and biochemical mechanisms to counter the effect of T. absoluta attack. Results The tolerant genotype showed an enhanced constitutive barrier possibly as result of the higher density of trichomes and increased inducible reactions upon mild infestation thanks to the activation/repression of key transcription factors regulating genes involved in cuticle formation and cell wall strength as well as of antinutritive enzymes, and genes involved in the production of chemical toxins and bioactive secondary metabolites. Conclusions Overall, our findings suggest that tomato resilience to the South America pinworm is achieved by a combined strategy between constitutive and induced defense system. A well-orchestrated modulation of plant transcription regulation could ensure a trade-off between defense needs and fitness costs. Our finding can be further exploited for developing T. absoluta tolerant cultivars, acting as important component of integrated pest management strategy for more sustainable production.

Numerical Evaluation of Safety Wall Bending Strength during Hydrogen Explosion

The main aims of this study are to assess numerically the stress state of a solid wall which is installed at the hydrogen fueling station in order to protect personnel from the consequences of the accidental hydrogen explosion, define the bending stress values in the foot of the wall exposed to explosion wave pressure forces and located at different distances from explosion epicenter in order to choose appropriate construction material of the wall and assess the minimum thickness of the wall satisfying bending strength condition. A three-dimensional mathematical model of hydrogen-air mixture explosion is used to define the distribution of the maximum overpressure on the wall surface. To assess the bending stress state at the foot of the wall, the design scheme of a cantilever beam is considered. It is assumed that the maximum overpressure force field influences the wall at the same time to assess the worst possible scenario. Actually, the computer-based methodology of how to resolve a coupled problem of explosion gas dynamics and defense wall strength is suggested. This technique allows evaluating of the construction parameters of the wall, which protects the personnel against consequences of the explosion wave exposure, without the destruction of the wall.

Tomato Endurance to Tuta Absoluta Is Mediated by Reinforcement of Leaf Barriers and Induction of Chemical Reaction

Background: The leaf miner, Tuta absoluta, is a destructive pest of tomato that causes important losses worldwide. Breeding of resistant/tolerant tomato cultivars could be an effective strategy for T. absoluta management but, despite the economic importance of tomato, very limited information is available about its response to this treat. To elucidate the defense mechanisms to herbivore feeding a comparative analysis was performed between a tolerant and susceptible cultivated tomato at both morphological and transcriptome level to highlight constitutive leaf barriers, molecular and biochemical mechanisms to counter the effect of T. absoluta attack. Results: The tolerant genotype showed an enhanced constitutive barrier due to the higher density of trichomes and increased inducible reactions upon mild infestation thanks to the activation/repression of key transcription factors regulating genes involved in cuticle formation and cell wall strength as well as of antinutritive enzymes, and genes involved in the production of chemical toxins and bioactive secondary metabolites. Conclusions: Overall, our findings suggest that tomato resilience to the leaf miner is achieved by a combined strategy between constitutive and induced defense system. A well-orchestrated modulation of plant transcription regulation ensures a trade-off between defense needs and fitness costs. Our finding can be further exploited for developing T. absoluta tolerant cultivars, acting as important component of integrated pest management strategy for more sustainable production.

Risk Factors and Mouse Models of Abdominal Aortic Aneurysm Rupture

Abdominal aortic aneurysm (AAA) rupture is an important cause of death in older adults. In clinical practice, the most established predictor of AAA rupture is maximum AAA diameter. Aortic diameter is commonly used to assess AAA severity in mouse models studies. AAA rupture occurs when the stress (force per unit area) on the aneurysm wall exceeds wall strength. Previous research suggests that aortic wall structure and strength, biomechanical forces on the aorta and cellular and proteolytic composition of the AAA wall influence the risk of AAA rupture. Mouse models offer an opportunity to study the association of these factors with AAA rupture in a way not currently possible in patients. Such studies could provide data to support the use of novel surrogate markers of AAA rupture in patients. In this review, the currently available mouse models of AAA and their relevance to the study of AAA rupture are discussed. The review highlights the limitations of mouse models and suggests novel approaches that could be incorporated in future experimental AAA studies to generate clinically relevant results.

Predictors of Abdominal Aortic Aneurysm Risks

Computational biomechanics via finite element analysis (FEA) has long promised a means of assessing patient-specific abdominal aortic aneurysm (AAA) rupture risk with greater efficacy than current clinically used size-based criteria. The pursuit stems from the notion that AAA rupture occurs when wall stress exceeds wall strength. Quantification of peak (maximum) wall stress (PWS) has been at the cornerstone of this research, with numerous studies having demonstrated that PWS better differentiates ruptured AAAs from non-ruptured AAAs. In contrast to wall stress models, which have become progressively more sophisticated, there has been relatively little progress in estimating patient-specific wall strength. This is because wall strength cannot be inferred non-invasively, and measurements from excised patient tissues show a large spectrum of wall strength values. In this review, we highlight studies that investigated the relationship between biomechanics and AAA rupture risk. We conclude that combining wall stress and wall strength approximations should provide better estimations of AAA rupture risk. However, before personalized biomechanical AAA risk assessment can become a reality, better methods for estimating patient-specific wall properties or surrogate markers of aortic wall degradation are needed. Artificial intelligence methods can be key in stratifying patients, leading to personalized AAA risk assessment.

Ethanol and H2O2 stresses enhance lipid production in an oleaginous Rhodotorula toruloides thermotolerant mutant L1-1

Stress tolerance is a desired characteristic of yeast strains for industrial applications. Stress tolerance has been well described in Saccharomyces yeasts but has not yet been characterized in oleaginous Rhodotorula yeasts even though they are considered promising platforms for lipid production owing to their outstanding lipogenicity. In a previous study, the thermotolerant strain L1–1 was isolated from R. toruloides DMKU3-TK16 (formerly Rhodosporidium toruloides). In this study, we aimed to further examine the ability of this strain to tolerate other stresses and its lipid productivity under various stress conditions. We found that the L1–1 strain could tolerate not only thermal stress but also oxidative stress (ethanol and H2O2), osmotic stress (glucose) and a cell membrane disturbing reagent (DMSO). Our results also showed that the L1–1 strain exhibited enhanced ability to maintain ROS homeostasis, stronger cell wall strength and increased levels of unsaturated membrane lipids under various stresses. Moreover, we also demonstrated that ethanol-induced stress significantly increased the lipid productivity of the thermotolerant L1–1. The thermotolerant L1–1 was also found to produce a higher lipid titer under the dual ethanol-H2O2 stress than under non-stress conditions. This is the first report to indicate that ethanol stress can induce lipid production in an R. toruloides thermotolerant strain.

ABDOMINAL RECTUS DIASTASIS (ARD) CORRECTION FOR PAIN REDUCTION AND IMPROVEMENT OF ABDOMINAL WALL MUSCLE STRENGTH

Introduction: Rectus abdominis diastasis (RAD) can be described as a condition in which rectus abdominis muscles are separated by an abnormally wide distance i.e. any separation of more than 2 cm is considered to be abnormal. Several aetiological factors may lead to protrusion of the anterior abdominal wall. It is a common complaint in women after childbirth. Abdominal rectus diastasis (ARD) is a sequele of the expansion of the abdominal contents during pregnancy or massive weight loss and/or congenital disproportion of the collagen III/I ratio. Operative repair of ARD can improve abdominal wall function. Various methods for ARD repair have been described. These differ by approach like open versus laparoscopic, the position of suture placement, numbers of layers of sutures, suture material, and use of mesh. Also it can be combined with mesh augmentation in the IPOM technique for enhanced stabilization of the abdominal wall. Material and Methods: Eligible patients were randomized to either one of two operative procedures or a 3-month, dedicated training program which serve as a control group. ARD width was assessed clinically and confirmed with computed tomography scanning. Endpoints were assessed after 6 months for relapse of the ARD, pain, restriction of daily activities and improvement in muscle strength. Abdominal wall strengthe was assessed by Visual analogue scale (VAS). Results: A total of 72 patients were enrolled into the study (70 female and 2 male). 24 patients were enrolled in each group. 13 patients had undergone cesarean section in the Quill group and 12 in the mesh group. According to VAS scale no statistically significant difference was seen between the two operative groups regarding perceived improvement in abdominal wall strength. But it was significantly higher in operated group as compared to training group. Abdominal muscular strength was improved in all the three groups. Improvement in abdominal wall strength was lower in training group compared to operative groups. No relapse was observed in operative groups. Conclusion: Operative repair of ARD can provide functional stability and improvement in pain and physical parameters it also improves quality of life, and reduce functional disability. Keywords: ARD, Quill SRS, Mesh repair, VAS, linea alba (LA)