Regulation of N-methyl-D-aspartate receptor function by constitutively active protein kinase C

The ability of the constitutively active fragment of protein kinase C (PKM) to modulate N-methyl-D-aspartate (NMDA)-activated currents in cultured mouse hippocampal neurons and acutely isolated CA1 hippocampal neurons from postnatal rats was studied using patch-clamp techniques. The responses of two heterodimeric combinations of recombinant NMDA receptors (NR1a/NR2A and NR1a/NR2B) expressed in human embryonic kidney 293 cells were also examined. Intracellular applications of PKM potentiated NMDA-evoked currents in cultured and isolated CA1 hippocampal neurons. This potentiation was observed in the absence or presence of extracellular Ca2+ and was prevented by the coapplication of the inhibitory peptide protein kinase inhibitor(19-36). Furthermore, the PKM-induced potentiation was not a consequence of a reduction in the sensitivity of the currents to voltage-dependent blockade by extracellular Mg2+. We also found different sensitivities of the responses of recombinant NMDA receptors to the intracellular application of PKM. Some potentiation was observed with the NR1a/NR2A subunits, but none was observed with the NR1a/NR2B combination. Applications of PKM to inside-out patches taken from cultured neurons increased the probability of channel opening without changing single-channel current amplitudes or channel open times. Thus, the activation of protein kinase C is associated with potentiation of NMDA receptor function in hippocampal neurons largely through an increase in the probability of channel opening.     

Typing of freshly isolated strains of Salmonella typhi using bacteriophages and colicins

The effect of ketamine administered to 20 rabbits in a single dose and in fractionated doses on the blood clotting system was studied. The following blood clotting indices were determined: thrombelastography (TEG), plasma thrombin time, platelet count, euglobulin lysis time. No statistically significant differences were observed in the activity of clotting and fibrinolysis systems in the group of animals receiving a single dose of ketamine and in the group receiving fractionated doses. The obtained results suggest that ketamine as an agent used for dissociative anaesthesia can be administered safely in serious conditions associated with disturbances in the haemostasis system.     

An analysis of preliminary results in screening for prostatic cancer]

450 males aged over 50 years free of urological symptoms were screened for prostatic cancer using three techniques; finger rectal examination (FRE), transrectal ultrasound investigation (TUI), assay for prostatic specific antigen in the serum (SPSA). SPSA quantities under 4 ng/ml, 4-10 ng/ml, 10-20 ng/ml, over 20 ng/ml were registered in 206(45.8%), 135(30%), 69(15.4%) and 40(8.8%) patients, respectively. Detectability of prostatic cancer increases by 33,37.9, 45.5, 69.2% due to TUI, FRE, TUI + FRE, all the three methods, respectively. Prostatic biopsy was needed in 102 (22.7%) cases. From the 450 examinees, prostatic cancer was diagnosed in 25 (5.6%). SPSA was high in all of them, higher than 10 ng/ml in 92%. 20 (80%) of 25 patients with cancer had early stages of the disease (TI-2). The study is going on.     

Variants of hyperosmolarity syndrome in diabetes mellitus patients in critical conditions

Recently, high lethality of critical conditions in diabetes mellitus patients has been attributed to the presence of hyperosmolarity syndrome. The authors consider this problem in terms of plasm osmolarity parameters, pathogenesis and diagnostic criteria of hyperosmolarity. Present-day clinical variants of hyperosmolarity syndrome are characterized.     

Autoimmune hepatitis (history of the research, current aspects)

Important achievement in the study of autoimmune hepatitis are shown, particularly in establishing the role of hepatitis viruses, other hepatotropic viruses and some medicines. The last classification of chronic hepatitis based on the etiology, autoimmune hepatitis considers autoimmune hepatitis as a disease of unknown etiology. It is thought valid that investigation of autoimmune reactions produced by hepatitis viruses and other agents will enable a revision of classification of chronic hepatitis.     

Retroperitoneal endometriosis causing cyclical ureteral obstruction

Cooperativity between redox and protonation centres is known to be crucial for the function of complex proteins, but it is often difficult to describe in terms of thermodynamic parameters. Cytochrome c3 is a good model for these studies since, while retaining the overall complexity of larger systems, it is suitable for detailed crystallographic and spectroscopic studies. Assignment of the haem substituent NMR resonances, together with NMR redox titrations of cytochrome c3 from D. desulfuricans ATCC 27774, was used to correlate relative redox potentials to specific haems in the structure: haem II approximately equal to haem I < haem IV < haem III. This order is different from that determined for the homologous proteins studied and in disagreement with that previously reported for this cytochrome (Morais, J., Palma, N., Fraz?o, C., Caldeira, J., LeGall, J., Moura, I., Moura, J.J.G. and Carrondo, M.A. (1995) Biochemistry 34, 12830-12841).