The neuromuscular blocking activity of spectinomycin on the rat sciatic nerve-gastrocnemius muscle preparation

Spectinomycin displays a dose-dependent neuromuscular blocking activity in vivo. The neuromuscular blockade elicited by spectinomycin is potentiated by d-tubocurarine. Neostigmine methylsulfate is unable to reverse the neuromuscular blocking activity of spectinomycin, whereas calcium chloride counteracts the neuromuscular blockade induced by this antibiotic.     

Changes in the Frequency of Splenic Immunocompetent Cs in Rats Exposed To Carbon Monoxide During Gestation

The aim of the present study was to evaluate whether prenatal exposure to relatively low concentrations of carbon monoxide (CO) may alter the frequency of splenic cells either in young (15—21 days) or in aged rats (18 months). Wistar female rats were exposed to 75 and 150 ppm of CO from day 0 to day 20 of pregnancy, respectively.

The results show that prenatal exposure to 150 ppm of CO significantly decreases the number of leucocyte common antigen (LCA±) cells in 21 day old male rats, whereas other cellular populations, such as macrophages, Major Histocompatibility (MHC) II cells, T and B lymphocytes display only a trend towards a reduction without achieving statistical significance. The alterations in LCA± cell frequency produced by gestational exposure to CO were reversible.

These data further extend previous findings showing that rats prenatally exposed to moderate concentrations of CO exhibit subtle immunological changes in the absence of overt signs of toxicity.     

Rch1, a protein that specifically interacts with the RAG-1 recombination-activating protein.

RAG1 and RAG2 are lymphoid-specific genes that together induce V(D)J recombinase activity in a variety of nonlymphoid cell types. While no other lymphoid-specific factors are required to induce recombination, other factors with more widespread expression patterns have been implicated in the reaction. However, none of these factors have been cloned, and their relationship to the RAG proteins is unclear. Using the yeast two-hybrid assay, we have identified RCH1, a gene encoding a protein of molecular weight 58,000 that interacts specifically with RAG-1. The predicted Rch1 protein sequence is 47% identical to yeast SRP1, a protein associated with the nuclear envelope. A truncated form of Rch1, which retains the ability to interact with RAG-1, reduces V(D)J recombination activity in HeLa cells.     

Up-regulation of Polysialic Acid in Peripheral Myelinated Axons of Rat Chronically Exposed to 2,5-Hexanedione

Abstract: Myelinated nerve fibres isolated from Wistar rats chronically exposed to 2,5-hexanedione (0.8 ml/kg/day, intraperitoneally) over a period of 20 days, were stained with lectin-horseradish peroxidase conjugates. The lectins with high affinity for terminal D-galactopyranosyl residues, Bandeiraea simplicifolia-B₄ (BSA I-B₄) and peanut agglutinin (PNA), showed glycoconjugates in the control nodes of Ranvier. In the treated animals, application of PNA-HRP caused weak reactivity to the node of Ranvier; digestion with sialidase prior to the application of PNA-HRP conjugate enhanced reactivity, thus revealing the presence of a sialoglycoprotein. The results indicate that glycoconjugates of the Ranvier node undergo a rearrangement during exposure to 2,5-hexanedione. In particular, neutral glycoproteins with terminal galactose are replaced by sialoglycoproteins. These findings are consistent with the proposed role of polysialic acid as a regulator of axonal behaviour during regeneration.     

The influence of coracoacromial arch anatomy on rotator cuff tears

We performed an anatomic study of 140 cadaver shoulders to correlate the influence of the coracoacromial arch anatomy on full-thickness rotator cuff tears (RCTs). The presence, location, and size of RCTs were initially documented. After dissection was complete 14 dimensional parameters, including humeral head size, glenoid size, and location of bony landmarks, were obtained by direct measurement. These data were entered into a computerized data base and 24 additional parameters (lengths, angles, areas) were calculated. The data were then subjected to analysis of variance and paired and unpaired t tests to determine correlation between the multiple parameters, age, sex, and left-to-right variance with RCTs. Three-dimensional computer modeling was then used to investigate the role of humeral head position in defining the available space within the coracoacromial arch (supraspinatus outlet). Overall 20% of the cadaver group exhibited full-thickness RCTs. The age group 60 years and older had a 29% incidence of RCTs compared with 5% in the group less than 60 years of age. The RCT group had a significantly greater anterior projection of the acromion than had the intact group (difference = 3.8 mm, p < 0.007). Acromial tilt was 28.5° in the RCT group and 33.5° in the intact group (p < 0.007). The supraspinatus outlet area was calculated by determining the total coracoacromial arch area and subtracting the area of the humeral head within the coracoacromial arch. The supraspinatus outlet was 22.5% smaller in the RCT group (p < 0.07). By using a series of measured and calculated parameters, we were able to characterize the anatomy of the coracoacromial arch and its relationship with the humeral head and to correlate variations in structure with the presence of RCTs. These findings may aid in our understanding of outlet impingement as a factor in the cause of RCTs.     

Non–IgE- or Mixed IgE/Non–IgE-Mediated Gastrointestinal Food Allergies in the First Years of Life: Old and New Tools for Diagnosis

non-IgE and mixed gastrointestinal food allergies present various specific, well-characterized clinical pictures such as food protein-induced allergic proctocolitis, food protein-induced enterocolitis and food protein-induced enteropathy syndrome as well as eosinophilic gastrointestinal disorders such as eosinophilic esophagitis, allergic eosinophilic gastroenteritis and eosinophilic colitis. The aim of this article is to provide an updated review of their different clinical presentations, to suggest a correct approach to their diagnosis and to discuss the usefulness of both old and new diagnostic tools, including fecal biomarkers, atopy patch tests, endoscopy, specific IgG and IgG4 testing, allergen-specific lymphocyte stimulation test (ALST) and clinical score (CoMiss).     

Incidence,risk factors and outcome of acute kidney injury (AKI) in patients with COVID-19

Clinical and Experimental Nephrology - Acute kidney injury (AKI) is a severe complication of coronavirus disease-2019 (COVID-19). This study aims to evaluate incidence, risk factors and...     

Accumulation of zinc-phthalocyanine (Zn-Pc) in the aorta of atherosclerotic rabbits

Phthalocyanines are structural analogs of porphyrins and are characterized by a closely similar mechanism of transport in the bloodstream. We evaluated the accumulation of liposomebound Zn(II)-phthalocyanine (Zn-Pc) by atherosclerotic aortas in rabbits. The biodistribution of intravenously injected Zn-Pc (0.023 mg/kg body weight) in the serum and some tissues resembled that previously observed for other experimental animals. Moreover, significant amounts of Zn-Pc were recovered from the aorta of the atherosclerotic and not of the normal rabbits. The maximum accumulation (circa 0.04g of Zn-Pc g^–1 tissue) was observed at 3 h after injection. We conclude that Zn-Pc might act as a fluorescence marker for atheromas and it has a potential as a phototherapeutic agent in atherosclerosis.This topic was presented at the International Conference on Photodynamic Therapy and Medical Laser Applications, held in London on July 19–21, 1988.