Changes in the cytoskeletal proteins, sarcoplasmic reticulum, and capillaries in acute relaxant-steroid myopathy (ARSM) in contrast to the corticosteroid myopathy

Since we reported a case of acute relaxant-steroid myopathy (ARSM) in 1994, we continued histological studies and compared the findings with those in a case of corticosteroid myopathy (CM). It was revealed that (1) dystrophin, spectrin, beta dystroglycan, and sarcoglycans on the cell surface were decreased, (2) regular arrangement of the sarcoplasmic reticulum was lost, and (3) some capillaries were degenerated. Since none of these changes were seen in CM, it became clear that ARSM is different from CM. It was estimated that continuous administration of non-depolarizing muscle relaxant produces a state akin to denervation. Combination of denervation, immobilization and circulatory disturbance in ARSM not only augments the effects of corticosteroids, but they produce changes different from CM, namely impairment of the cell membrane system (both internal and external) and capillary degeneration. Received: 7 January 1998 / Revised: 12 August 1998, 14 October 1998 / Accepted 21 October 1998     

A newly developed assay for melatonin using cells expressing human mel-1a receptor

We have developed a radioreceptor binding assay (RRA) method for melatonin using membranes from Chinese hamster ovary cells that can stably express human mel-1a receptors. We measured melatonin levels in plasma samples collected every 4h for 24h using the RRA and radioimmunoassay (RIA) methods, simultaneously. There was a statistically significant correlation between the melatonin levels measured by the two methods, this newly developed method providing a sensitive bioassay. As it is possible to circumvent the cross-reactivity usually occurring in the RIA method, this method may be an important tool for detecting bioactive substances relative to the mel-1a receptor.     

DNAzyme Cleavage of CAG Repeat RNA in Polyglutamine Diseases

CAG repeat expansion is the genetic cause of nine incurable polyglutamine (polyQ) diseases with neurodegenerative features. Silencing repeat RNA holds great therapeutic value. Here, we developed a repeat-based RNA-cleaving DNAzyme that catalyzes the destruction of expanded CAG repeat RNA of six polyQ diseases with high potency. DNAzyme preferentially cleaved the expanded allele in spinocerebellar ataxia type 1 (SCA1) cells. While cleavage was non-allele-specific for spinocerebellar ataxia type 3 (SCA3) cells, treatment of DNAzyme leads to improved cell viability without affecting mitochondrial metabolism or p62-dependent aggresome formation. DNAzyme appears to be stable in mouse brain for at least 1 month, and an intermediate dosage of DNAzyme in a SCA3 mouse model leads to a significant reduction of high molecular weight ATXN3 proteins. Our data suggest that DNAzyme is an effective RNA silencing molecule for potential treatment of multiple polyQ diseases.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13311-021-01075-w.     

High production of nondisjunction mutants in the offspring of Drosophila melanogaster females exposed to carbon dioxide at meiosis I

Drosophila melanogaster females homozygous for X-linked recessive markers, y and wⁱ, were exposed CO₂ and mated with y⁺ w⁺/Y males. The progeny were sampled and inspected for y wⁱ/y wⁱ/Y(XXY) and y⁺ w⁺/O (XO) mutants. The frequency of nondisjunction XXY mutants after a 90-min exposure to CO₂ increased 100-fold above the control level in the first-day brood but did not increase above the control level in the second to sixth broods, showing that CO₂ is an extremely potent inducer of nondisjunction in mature oocytes during meiotic metaphase I but is not harmful to immature oocytes. Nondisjunction-causing damage induced by CO₂ in mature oocytes disappeared completely within one day after CO₂ treatment, as evidenced by a reduction of the number of XXY mutants to the control level when the mating of CO₂-treated females was delayed by one day. CO₂-induced nondisjunction is probably due to damage to spindle microtubules in mature oocytes at metaphase I. N₂ is a less potent inducer of nondisjunction than CO₂. Maternal X-irradiation with 4 Gy did not induce XXY mutants, showing that medium-level radiation does not induce nondisjunction. The results support Gaul den's hypothesis that oxygen deficits and CO₂ increases in the microenvironment of mature oocytes can be potent inducers of nondisjunction. The possible relationship to the cluster of Down syndrome seen in Berlin shortly after the Chernobyl accident is discussed. Environ. Mol. Mutagen. 31:176–182, 1998 © 1998 Wiley-Liss, Inc.     

Synthesis of basement membrane by gastrointestinal cancer cell lines

Gastrointestinal adenocarcinoma-derived cell lines were studied in order to determine their pattern of expression of basement membrane components and their ability to form a basement membrane. In contrast to the well-preserved expression of laminin β2,β3,γ1, and γ2 chain mRNAs, five of eight gastrointestinal cancer cells lacked α3 mRNA. Immunohistochemical and electron microscopic examination of four cell lines transplanted subcutaneously to SCID mice demonstrated the presence of both α3 and α5 chains and the formation of a basal lamina in two cases. The other two cell lines lacked both α3 and α5 chains and could not form a basal lamina, suggesting that this deficiency may be a factor which affects their ability to form a basement membrane. This abnormality might play some role in stromal invasion by tumour cells in gastrointestinal cancer. Copyright © 1999 John Wiley & Sons, Ltd.     

Exercise-induced ST-segment changes permit prediction of improvement in left ventricular ischemic dysfunction after revascularization: Evaluation with positron emission tomographic measurements of regional myocardial blood flow and cardiac output

Background  Prediction of the recovery of left ventricular (LV) ischemic dysfunction after revascularization is important in patients with coronary artery disease (CAD). We investigated whether the improvement in LV ischemic dysfunction after revascularization could be predicted preoperatively by exercise-induced ST-segment changes. Methods and Results  Regional myocardial blood flow (RMBF) and cardiac output were measured with nitrogen 13-ammonia positron emission tomography at rest and during low-level exercise in 28 patients with angiographically proven CAD before and after successful revascularization and in 9 normal subjects. Before revascularization, exercise-induced upsloping ST-segment depression <1 mm 80 msec after the J-point was observed in 11 patients (group 1), horizontal depression of 1 to 1.5 mm was observed in 0 patients (group 2), and downsloping depression ≥1.5 mm was observed in 8 patients (group 3). The number of regions of critical CAD was greater in group 3 than in groups 1 and 2 (3.6±1.4 vs 1.6±0.7 and 2.2±1.1, p<0.001, p<0.02). Increase of RMBF in regions of critical CAD with exercise was lower in group 3 than in groups 1 and 2 (0.15±0.01 vs 0.22±0.01 and 0.18±0.02 ml/min per gram, p<0.0001, p <0.01). After revascularization, RMBF in regions of critical CAD both at rest and during exercise improved in groups 1 (0.49±0.15 to 0.60±0.18, 0.70±0.26 to 0.86±0.33 ml/min per gram, both p<0.05) and 2 (0.50±0.15 to 0.62±0.19, 0.67±0.26 to 0.89±0.31 ml/min per gram, both p<0.02), but was unchanged in group 3 (0.47±0.09 to 0.47±0.15, 0.62±0.17 to 0.64±0.23 ml/min per gram, both p=NS). Cardiac output at rest improved in groups 1 (4.98±0.43 to 5.35±0.50 L/min, p<0.02) and 2 (5.08±0.52 to 5.53±0.28 L/min, p<0.02), but was unchanged in group 3 (4.76±0.48 to 4.88±0.82 L/min, p=NS). Conclusions  Our results suggest that marked downsloping ST-segment depression induced by preoperative low-level exercise may predict a lack of improvement in LV ischemic dysfunction after revascularization. Presented in part at the 69th Scientific Sessions of the American Heart Association, New Orleans, Louisiana, November 1996.