IGF-II dependent autocrine growth in cell lines derived from renal tumours of childhood

Aims—To determine the role of insulin-like growth factors (IGF) in the proliferation of tumour cells, by studying the mitogenic response to IGFs of three cell lines of differing phenotype established from both malignant rhabdoid and Wilms tumour, representing a range of cell types (GOS 4, G401, and T3/73).     

Induction of heat shock proteins in lymphocytes increases with mitogen stimulation

The effect of the growth state of a cell on the ability of hyperthermia to induce the synthesis of heat shock proteins (HSPs) was studied in resting and concanavalin A (ConA)-stimulated lymphocytes. Hyperthermia induced the synthesis of hsp 110, hsp 90, hsc 70, and hsp 70 in both resting and ConA-stimulated lymhocytes, and ConA-treatment induced the synthesis of the hsp 90 and hsc 70 at normal temperature. The induction of the synthesis of hsp 110 and hsp 70 by hyperthermia was 3- to 6-fold higher for lymphocytes cultured with ConA for 12 and 24 h than in non-stimulated lymphocytes. Thus, lymphocytes induced to undergo proliferation showed a greater response to hyperthermia than resting lymphocytes.     

Bacillus thuringiensis insecticidal delta-endotoxin: diversity of crystal proteins and its relatedness to the toxicity spectrum

Bacillus thuringiensis strains produce crystal delta-endotoxins which exhibit a diverse toxicity spectrum. In order to explore the basis of toxin specificity, a comparison of the activity of 13 strains belonging to seven serotypes was made against three insect species. The delta-endotoxin crystals were purified and their polypeptide composition analyzed by SDS-PAGE. Among the strains studied, the delta-endotoxins consist of a variety of crystal proteins in the 60-144 KDa size range. On the basis of molecular mass, endotoxins maybe grouped into two classes; one contained both high (125-144 KDa, P1) and medium sized (60-66 KDa, P2) proteins and a second class consisting of only the high Mr polypeptides. Immunoblotting with B. aizawai P1 antiserum revealed antigenic cross-reaction with one or more of the polypeptides in 125-144 KDa range in all the strains studied. When the crystal proteins from different strains were immunoblotted with kurstaki P2 antiserum, none of the P1 protein crossreacted suggesting that the P1 and P2 proteins are not structurally related. However, the B. kurstaki P2 antiserum crossreacted with 66 KDa proteins in some other strains which underlines a structural homology in this class of the toxic polypeptides. Toxicity studies revealed that the high Mr P1 proteins of all the strains in this study were active against lepidopteran (Pieris brassicae and Diacrisia obliqua) larvae. B. thuringiensis aizawai strains exhibit a dual toxicity associated with the high Mr (130-135 KDa; P1) proteins. The P2 crystal proteins (60-66 KDa) also showed dual toxicity against the lepidopteran and dipteran larvae but were found to be structurally and immunologically distinct.     

A comparative study of allometric scaling with plasma concentrations predicted by species-invariant time methods

The objective of this study is to compare the empirical allometric approaches with species invariant time methods using equivalent time, kallynochron, apolysichron, and dienetichrons. Pharmacokinetic parameters (clearance, volume of distribution, and elimination half-life) of ethosuximide, cyclosporine and ciprofloxacin were scaled-up from animal data obtained from the literature. Two methods were utilized to generate plots for the prediction of clearance in humans: (i) clearance versus body weight (simple allometric equation); and (ii) the product of clearance and maximum life-span potential (MLP) versus body weight. Plasma concentrations of each of the drugs were predicted using elementary and complex Dedrick plots, equivalent time with an exponent of 0.25 and equivalent time with the exponent obtained from the plot of body weight and half-life. Plasma concentrations of cyclosporine and ciprofloxacin were also predicted by MLP normalization (dienetichrons). Almost similar results in the pharmacokinetic parameters of the tested drugs were obtained by the allometric approach and by the species invariant time methods.     

Post‐COVID‐19 splenic infarction in a patient with chronic atrial fibrillation: A case report

We describe splenic infarction (SI), an infrequent condition, in an 82‐year‐old COVID‐19 patient with chronic atrial fibrillation (AF). COVID‐19 may cause thrombosis, and AF is a predisposing factor for splenic infarction. Suspicion of SI may be warranted in COVID‐19 patients with abdominal pain, especially if a predisposing factor exists.