Mechanism of the radiation-protective effect of indralin

Output from the interpositus nucleus can inhibit the inferior olive, probably via the GABA-ergic nucleo-olivary pathway. It has been suggested that the function of this inhibition might be to regulate synaptic plasticity resulting from parallel fibre/climbing fibre interaction in cerebellar Purkinje cells, by providing negative feedback information to the olive. Thus, when a learned response, generated by the interpositus nucleus, reaches a sufficient amplitude, the olive would be inhibited and further learning blocked. This suggestion was tested in a classical conditioning paradigm. Decerebrate ferrets were trained using electrical skin stimulation of the forelimb as the conditioned stimulus (CS) and periorbital stimulation as the unconditioned stimulus (US). Climbing fibre responses evoked in Purkinje cells by the US were recorded as surface field potentials in the part of the c3 zone controlling eyeblink. It was found that the CS did not inhibit the olive at the beginning of training, but when conditioned responses were large, the olive was inhibited by the CS in some animals. After a number of unpaired CS presentations, which caused extinction of the conditioned response, the inhibition disappeared. The size of individual conditioned responses correlated negatively with the size of the climbing fibre responses evoked by the US. Climbing fibre responses evoked by direct stimulation of the olive were also inhibited. It was concluded that cerebellar output during performance of a conditioned response inhibits the inferior olive. The results thus support the hypothesis of a cerebellar locus of conditioning and are consistent with the proposed role of cerebello-olivary inhibition.     

A strain of the yeast Saccharomyces cerevisiae for testing environmental mutagens based on interaction of the mutations rad2 and him1

The interaction between mutations at the RAD2 and HIM1 genes was studied. The RAD2 gene encodes endonuclease involved in nucleotide excision repair. Mutants at this gene are highly sensitive to the lethal effect of a variety of mutagens. The product of the HIM1 gene is needed for correction of mismatched bases and repair of premutational DNA damage. Mutations in this gene lead to the formation of the mutator phenotype and high sensitivity to induced mutagenesis. The double rad2 him1 mutant manifested the synergic type of interaction. The level of UV-induced mutagenesis in the double mutant was five times higher than in single mutants, and the absolute yield of forward mutations in five genes controlling adenine biosynthesis was 1 to 2%. UV-induced mutagenesis was increased, at low doses, by several orders of magnitude in the double mutant, compared to the wild-type strain. The high level of mutagenesis in this mutant was caused by ethyl and methyl methanesulfonate. These properties of the stock with the double rad2 him1 mutation makes it promising as a tester in analysis of the gene toxicity of different substances.     

The dynamic clinical manifestations of ischemic heart disease during the rehabilitation at a low-altitude health resort of patients who have undergone surgical myocardial revascularization

Left ventricular myocardial contractility was found essential in dynamics of clinical IHD picture in patients on rehabilitation treatment at low mountain resorts. All the patients have previously undergone surgical myocardial revascularization. Patients with normal left ventricular myocardial contractility benefited most of all.     

Digestibility, apparent mineral absorption, and voluntary intake by horses fed alfalfa, tall fescue, and caucasian bluestem

Alfalfa (Medicago sativa L.), low-endophyte (< 5%) tall fescue (Festuca arundinacea Schreb.), and caucasian bluestem (Bothriochloa caucasica [Trin.] C.E. Hubbard) were fed as chopped hay to six Arabian geldings (BW 441 kg; SE 2) in intake and digestibility experiments to determine nutritional value for horses at maintenance. Each experimental design was a replicated Latin square. Alfalfa was higher in DM and CP digestibility, IVDMD, apparent absorption of Ca, K, and S, and voluntary intake than the grasses (P < .05). Caucasian bluestem was higher in Zn but was lower in CP, TNC, Mg, P, K, S, and Cu concentrations than tall fescue. Crude protein digestibility and apparent absorption of Mg, K, and S were higher (P < .05) for tall fescue than for caucasian bluestem. Geldings fed alfalfa for ad libitum intake had higher serum concentrations of vitamin A, blood urea nitrogen, P, S, and Cu than geldings fed grass hays. Serum Zn was higher (P < .05), whole blood Se tended to be higher (P < .06), and BUN was lower (P < .05) in geldings fed caucasian bluestem than in those fed tall fescue. All forages met requirements for CP, Ca, Mg, K, and Fe when fed for ad libitum intake but were deficient in Cu for horses at maintenance. Caucasian bluestem was borderline in CP and was deficient in P but was the only forage that met the Zn requirement for the horses. Based on these results, caucasian bluestem could be a useful hay for horses but may require supplementation of CP and P.     

DNA- and RNA-hydrolyzing antibodies from the blood of patients with various forms of viral hepatitis

Antibodies (Abs) hydrolyzing proteins, DNA, and RNA are detected in the blood of patients with various autoimmune diseases. In the present work, homogeneous preparations of IgG Abs from the blood of the healthy donors as well as patients with A, B, C, and delta types of viral hepatitis, influenza, pneumonia, tuberculosis, tonsillitis, duodenal ulcer, and some types of cancer were purified. For the first time, the fraction of IgG and its Fab fragments of patients with viral hepatitis were shown to have high DNA- and RNA-hydrolyzing activity. In case of Abs from the healthy donors and patients with other diseases, high activity of Abs was not detected. The data obtained by various methods indicate that the activity of hepatitis Abs is an intrinsic property of the immunoglobulins. The relative rates of hydrolysis of cCMP, poly(U), poly(A), poly(C), and tRNA(Phe) by hepatitis Abs were compared with those of RNase A and other RNases from human blood. Significant differences in activities of Abs and nucleases in hydrolysis of model substrates were demonstrated. Thus, catalytically active Abs can appear in the blood of patients not only with autoimmune disorders, but with viral diseases as well.