Inherited disorders of the neuromuscular junction: an update

Congenital myasthenic syndromes (CMSs) are a group of heterogeneous inherited disorders caused by mutations in genes affecting the function and structure of the neuromuscular junction. This review updates the reader on established and novel subtypes of congenital myasthenia, and the treatment strategies for these increasingly heterogeneous disorders. The discovery of mutations associated with the N-glycosylation pathway and in the family of serine peptidases has shown that causative genes encoding ubiquitously expressed molecules can produce defects at the human neuromuscular junction. By contrast, mutations in lipoprotein-like receptor 4 (LRP4), a long-time candidate gene for congenital myasthenia, and a novel phenotype of myasthenia with distal weakness and atrophy due to mutations in AGRN have now been described. In addition, a pathogenic splicing mutation in a nonfunctional exon of CHRNA1 has been reported emphasizing the importance of analysing nonfunctional exons in genetic analysis. The benefit of salbutamol and ephedrine alone or combined with pyridostigmine or 3,4-DAP is increasingly being reported for particular subtypes of CMS.     

Topical 5‐azacytidine accelerates skin wound healing in rats

The development of new methods to improve skin wound healing may affect the outcomes of a number of medical conditions. Here, we evaluate the molecular and clinical effects of topical 5‐azacytidine on wound healing in rats. 5‐Azacytidine decreases the expression of follistatin‐1, which negatively regulates activins. Activins, in turn, promote cell growth in different tissues, including the skin. Eight‐week‐old male Wistar rats were submitted to 8.0‐mm punch‐wounding in the dorsal region. After 3 days, rats were randomly assigned to receive either a control treatment or the topical application of a solution containing 5‐azacytidine (10 mM) once per day. Photo documentation and sample collection were performed on days 5, 9, and 15. Overall, 5‐azacytidine promoted a significant acceleration of complete wound healing (99.7% ± 0.7.0 vs. 71.2% ± 2.8 on day 15; n = 10; p < 0.01), accompanied by up to threefold reduction in follistatin expression. Histological examination of the skin revealed efficient reepithelization and cell proliferation, as evaluated by the BrdU incorporation method. 5‐Azacytidine treatment also resulted in increased gene expression of transforming growth factor‐beta and the keratinocyte markers involucrin and cytokeratin, as well as decreased expression of cytokines such as tumor necrosis factor‐alpha and interleukin‐10. Lastly, when recombinant follistatin was applied to the skin in parallel with topical 5‐azacytidine, most of the beneficial effects of the drug were lost. Thus, 5‐azacytidine acts, at least in part through the follistatin/activin pathway, to improve skin wound healing in rodents.     

Digital imaging analysis to assess scar phenotype

In order to understand the link between the genetic background of patients and wound clinical outcomes, it is critical to have a reliable method to assess the phenotypic characteristics of healed wounds. In this study, we present a novel imaging method that provides reproducible, sensitive, and unbiased assessments of postsurgical scarring. We used this approach to investigate the possibility that genetic variants in orofacial clefting genes are associated with suboptimal healing. Red‐green‐blue digital images of postsurgical scars of 68 patients, following unilateral cleft lip repair, were captured using the 3dMD imaging system. Morphometric and colorimetric data of repaired regions of the philtrum and upper lip were acquired using ImageJ software, and the unaffected contralateral regions were used as patient‐specific controls. Repeatability of the method was high with intraclass correlation coefficient score > 0.8. This method detected a very significant difference in all three colors, and for all patients, between the scarred and the contralateral unaffected philtrum (p ranging from 1.20^?05 to 1.95^?14). Physicians’ clinical outcome ratings from the same images showed high interobserver variability (overall Pearson coefficient = 0.49) as well as low correlation with digital image analysis results. Finally, we identified genetic variants in TGFB3 and ARHGAP29 associated with suboptimal healing outcome.     

Co-Infected HIV/Hepatitis Patients Compared With Chronic Liver Patients and Healthy Individuals: Respiratory Assessment Through Surface Electromyography and Spirometry

IntroductionCo-infected HIV and hepatitis subjects are candidates for a liver transplantation because of progressive liver disease. Chronic liver disease, co-infected or not, requires assessment of respiratory function before liver transplantation. The respiratory evaluation of these 2 groups compared with healthy individuals can define deficits, and this can impair a full recovery after transplant surgery.ObjectiveThis study sought to compare the respiratory profile in co-infected patients with chronic liver disease who are candidates for liver transplantation with that of healthy subjects.MethodsThrough respiratory evaluation of flows and lung volumes (spirometry), muscle activity (surface electromyography), and maximum pressure (manovacuometer), 250 people were distributed into 3 groups: 14 patients with HIV and liver disease, 65 healthy subjects, and 171 patients with chronic liver disease. The mean age (years) was respectively 47.5 ± 6.2, 48.3 ± 14.1, and 52.9 ± 8.5. The average body mass index (kg/m²) of the groups was 24.6 ± 4.5, 26.0 ± 3.2, and 28.5 ± 5.3, respectively.ResultsThere was a statistical difference among the groups in the root means square (RMS) rectus abdominis (μV) (P = .0016), RMS diaphragm (μV) (P = .0001), maximal inspiratory pressure (cmH₂O) (P = .001), forced exhaled volume at the end of first second (%) (P = .002), and maximal mid expiratory flow 25% to 75% (%) (P = .0001) for the Kruskal-Wallis test. The multivariate analysis among the groups showed that the RMS diaphragm had a tendency to discriminate the co-infected subjects.ConclusionsThe co-infected HIV group showed a muscle deficit of diaphragm and rectus abdominis activity, and the liver disease group showed lower indexes in volumes and respiratory flows.     

Histopathology and immunohistochemistry of tissues outside central nervous system in bovine rabies

We performed a histopathological and immunohistochemical study of tissues outside the central nervous system in 48 cases of bovine rabies confirmed by direct immunofluorescence and/or immunohistochemistry (IHC) of the central nervous system. In the bovines of this study, mononuclear inflammation in all ganglia (trigeminal, spinal, stellate, and celiac) and adrenal medulla was observed. This injury also occurred in 85 % of neuro-pituitaries in 55 % of pars intermediate and 15 % of the pars distalis of pituitary evaluated. IHC was positive in 92.31 % of lumbar spinal ganglia, 90.9 % of trigeminal ganglia, stellate ganglia of 41.67 and 16.67 % of the celiac ganglia. One of the evaluated adrenal (1/17) showed strong immunohistochemical labeling in the cytoplasm of pheochromocytes. The pituitary IHC was positive in one case in the neurohypophysis (1/20) and in one case in the pars intermedia of the adenohypophysis (1/20). Data from this study indicate that in suspected cases of rabies, besides the complex pituitary rete mirabile and trigeminal ganglion, the evaluation of other ganglia, particularly the lumbar spinal, and adrenal may also contribute to the diagnosis and understanding of the clinical presentation and pathogenesis of the disease in bovines.