Merosin-deficient congenital muscular dystrophy and cortical dysplasia.

Congenital muscular dystrophy (CMD) encompasses a heterogenous group of muscle disorders with autosomal recessive inheritance, characterized by muscular weakness and hypotonia at birth or within the first few months of life and developmental delay. Merosin-deficient CMD is a clinically distinct form which may be associated with significant abnormalities of the brain detectable by neuroimaging. We report two siblings of consanguineous parents with merosin-deficient CMD in an Irish family who in addition to the characteristic white matter abnormalities on neuroimaging, had occipital dysplasia. Clinical, electrophysiological muscle biopsy findings and neuroimaging were very similar in both cases. Although merosin-deficient CMD with white matter abnormalities on neuroimaging is well documented in the literature, the association with occipital dysplasia has only rarely been reported. The appearance of an identical cortical defect in these siblings suggests an underlying genetic mechanism.     

Quantitative computer‐assisted digital‐imaging upper airway analysis for obstructive sleep apnoea*

This was a prospective study of a new objective method which quantitatively analyses the upper airways in patients with obstructive sleep apnoea (OSA). Video‐nasopharyngoscopic examinations of the upper airways of 45 patients were carried out with an endoscopic calibrator. Images of the upper airway during quiet respiration and Mueller's manoeuvre in erect and supine positions were digitized by computer to generate the actual dimensions of obstructive sites. Measurements by the new method were validated by comparing 90 pairs of videoendoscopic images with upper airway magnetic resonance imaging (MRI) measurements at two identical levels. Quantitative precision is 100% for the retropalatal level and 95.6% for the retrolingual level with a tolerance of 0.5 cm² between the two methods. The absolute mean of the difference between the two methods of measurement is 0.08 cm² at the retropalatal level and 0.18 cm² at the retrolingual level. The agreement between the digital‐imaging videoendoscopic and MRI measurements was 93.3% for the retropalatal level and 95.6% for the retrolingual level. Quantitative computer‐assisted digital imaging is a reliable, cost‐effective clinical method of upper airway evaluation in OSA patients. This method allows us to examine the dynamic and static morphology objectively, measure surgical outcomes of upper airway, opening up new avenues for OSA management.     

An antibody targeting the N-terminal domain of SARS-CoV-2 disrupts the spike trimer

The protective human antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) focuses on the spike (S) protein, which decorates the virion surface and mediates cell binding and entry. Most SARS-CoV-2 protective antibodies target the receptor-binding domain or a single dominant epitope (“supersite”) on the N-terminal domain (NTD). Using the single B cell technology called linking B cell receptor to antigen specificity through sequencing (LIBRA-Seq), we isolated a large panel of NTD-reactive and SARS-CoV-2–neutralizing antibodies from an individual who had recovered from COVID-19. We found that neutralizing antibodies against the NTD supersite were commonly encoded by the IGHV1-24 gene, forming a genetic cluster representing a public B cell clonotype. However, we also discovered a rare human antibody, COV2-3434, that recognizes a site of vulnerability on the SARS-CoV-2 S protein in the trimer interface (TI) and possesses a distinct class of functional activity. COV2-3434 disrupted the integrity of S protein trimers, inhibited the cell-to-cell spread of the virus in culture, and conferred protection in human angiotensin-converting enzyme 2–transgenic (ACE2-transgenic) mice against the SARS-CoV-2 challenge. This study provides insight into antibody targeting of the S protein TI region, suggesting this region may be a site of virus vulnerability.     

Effects of antisense oligonucleotide-mediated depletion of tumor necrosis factor (TNF) receptor 1-associated death domain protein on TNF-induced gene expression

Tumor necrosis factor (TNF) receptor 1-associated death domain protein (TRADD) is an adaptor protein known to be involved in the TNF signaling pathway as well as signaling of other members of the TNF receptor superfamily, including DR3, DR6, p75(NTR), and the Epstein-Barr virus latent membrane protein 1. Current knowledge of the function of the adaptor protein has been derived from studies examining its over-expression in either wild-type or mutated forms. In this study, we analyzed the consequences of antisense oligonucleotide (ASO)-mediated depletion of endogenous TRADD on TNF induction of inflammation-related gene products, such as intercellular adhesion molecule-1, and associated kinase signaling pathways in human umbilical vein endothelial cells. A broader perspective of TRADD's role in TNF signaling was indicated by microarray gene expression analysis, where 20 of 24 genes that showed a 5-fold or greater increase in TNF-induced mRNA expression levels displayed a reduction in TNF-induced expression as a consequence of ASO-mediated knockdown of TRADD. Reduced activation of the nuclear factor-kappaB and c-Jun NH(2)-terminal kinase pathways, as measured by IkappaB-alpha protein levels and the extent of c-Jun phosphorylation, was also observed. These results indicate usage of antisense inhibitors of TRADD expression for modulating diseases associated with TRADD-dependent signal transduction pathways.     

Mutation in the K-ras gene at codon 12 does not correlate with disease progression in colorectal carcinoma patients treated with 5-FU/folinic acid biomodulated chemotherapy

To date the response rates to biomodulated 5-fluorouracil in patients with metastatic or unresectable colorectal carcinoma have been varied. Potentially responsive patients are difficult to identify and treatment schedules are both expensive and toxic. Thus, any method that could be used to predict patient response would be both clinically and economically valuable. Increased p53 protein levels have previously been shown to correlate with disease progression in a series of colorectal carcinoma patients treated with 5-FU/folinic acid biomodulated chemotherapy. In addition to mutation of the p53 tumour suppressor gene, mutation of the K-ras gene at codon 12 has also been shown to be a frequent occurrence in the step-wise progression from normal colonic mucosa to adenocarcinoma. Oncogenic activity in the ras family has recently been shown to correlate with decreased levels of apoptosis and thus increased resistance to both radiation and certain chemotherapeutic agents. The aim of the present study was therefore to investigate if a correlation existed between mutation of the K-ras gene at codon 12 and disease progression in the series of colorectal carcinoma patients previously evaluated for levels of p53 protein expression. Response to 5-FU/folinic acid was assessed radiologically by CAT scan (WHO criteria) and clinically by Karnofsky performance scale (KPS) 3 months after the initial treatment. The presence of a K-ras gene mutation was assessed with radiolabelled oligonucleotide probes on amplified patient DNA, dot blotted on to a nylon membrane. Fifty-two patients were assessed and 25% were found to possess mutations at codon 12 of their K-ras gene. In contrast to increased levels of p53 protein, K-ras mutation at codon 12 did not correlate with disease progression when assessed either radiologically or clinically.     

Zeitschriften

Journal of Molecular Medicine -