Alteration of RNA synthesis in vitro in intact cerebral cortex nuclei induced by convulsions in seizure-susceptible El mice

We examined the effects of convulsive seizures on in vitro RNA synthesis by cerebral cortex nuclei in El mice. The rate of incorporation of [3H]uridine-5'-triphosphate by intact nuclei during seizures was decreased to 47.4% compared with the rate during the interictal period, but gradually recovered. During the 30-min period after onset of seizures, the rate of RNA synthesis was significantly lower in El mice than in identically stimulated ddY mice. Seizures in El mice had no effect on liver RNA synthesis, suggesting that the alteration of RNA polymerase activity is specific to the brain. Analysis of gel electrophoresis of polyadenylated RNA synthesized in the presence of ammonium sulphate revealed a marked decrease in high-molecular weight RNA species 15 min after seizures in El mice compared with the pattern in nonstimulated ddY mice. This shift from high- to low-molecular weight RNA species was not attributable to RNase activity, but it appeared to be related RNA polymerase.

Sequence complexity of polyadenylate ribonucleic acid in El mouse brain

To elucidate the sequence complexity of polyadenylate messenger RNA [poly(A+)mRNA] regarding the seizure-susceptible El mouse brain, the proportion of complexity was measured by saturation hybridization using a single-copy DNA (scDNA) with excess RNA. At saturation, 3.81, 3.85 and 4.00% of scDNA hybridized with polysomal poly(A+)mRNAs of El(+), El(O) which had not been convulsed, and ddY (nonsusceptible) mice, respectively. The additive hybridization of a mixture of El(+) and ddY mouse mRNAs was 4.04%. The results suggest that there are considerable overlapping sets within the poly(A+)mRNA sequences between the ddY and El mice, but the complexity of ddY mice mRNA is slightly larger than that of the El mice, whereas poly(A+) heterogeneous nuclear RNA (hnRNA) hybridized with about 18% of scDNA in three strains of mice.

A crossover study of clocapramine and haloperidol in chronic schizophrenia

Therapeutic efficacy and target symptoms with clocapramine were compared with those with haloperidol by the crossover method, in a total of 26 chronic schizophrenic patients, by administration of one of the drugs for the first 14 weeks and the other for the next 14 weeks. The final global improvement rating showed no significant difference between the two groups, but clocapramine administered as first drug appeared to have a more pronounced effect than haloperidol. According to the improvement rate in psychotic symptoms, clocapramine tended to be superior to haloperidol for motor retardation, scanty speech and disturbance of thought. In addition the frequency of side-effects was lower with clocapramine than with haloperidol. Neither the side-effects nor abnormal laboratory test results were severe enough to terminate the trial. Clocapramine is considered to be equivalent or superior to haloperidol in terms of anti-psychotic effect in chronic schizophrenia, and is relatively safer than haloperidol.

Effect of convulsions of the synthesis of heterogeneous nuclear RNA associated with polyadenylate and oligoadenylate sequences from El mouse brain as a convulsive strain

Animals from the El (susceptible to seizures) and ddy (nonsusceptible) mouse strains were subjected to vestibular stimulation by tossing. After convulsions in the El mice, both the stimulated El mice and ddY mice were intracranially injected with [14C]- and [3H]adenosine, respectively. In the control experiment, nonstimulated El and ddY mice received radioactive adenosines in the same manner. The rate of incorporation of adenosine into brain nuclear RNA, expressed as a percentage of the 3H; 14C ratio, was reduced to an average of 68% at 15 min after convulsions, then increased and reached a control value at 5 h. This reduction in nuclear RNA synthesis was not due to alteration of the adenosine triphosphate pool. Gel electrophoresis of RNA revealed no obvious differences in the labeling distribution between El and ddY mice, but the synthesis of RNA species larger than 35S in heterogeneous nuclear RNA (HnRNA) was impaired in convulsed El mice. Nuclear resistant segments of HnRNA with both T1 RNase and RNase A, were chromatographed with poly(U)-Sepharose followed by urea-polyacrylamide gel electrophoresis. The ologo(A) and poly(A) segments consisted of 29, 19, and 11, and 203, 135, and 69 nucleotides, respectively. The convulsions of El mice reduced the incorporation of radioactive adenosines into oligo(A) and poly(A) segments, suggesting that they inhibited transcription as well as polyadenylation within HnRNA.

Trace element concentrations in hair, fingernails and plasma of patients with chronic renal failure on hemodialysis and hemofiltration

Trace element concentrations in hair and fingernails and plasma of nondialyzed, hemodialyzed and hemofiltered patients with chronic renal failure and healthy volunteers were measured by atomic and flameless atomic absorption spectrophotometry and neutron activation analysis. Plasma aluminum concentrations in all three groups of patients were higher than in the controls. Aluminum levels in plasma and red blood cells were higher in hemofiltered patients than in dialyzed patients. The aluminum concentrations in the hair of both nondialyzed and dialyzed patients was higher than in the controls, while that in the hemofiltered patients it was not. These elevated aluminum concentrations appear to be mainly caused by the use of aluminum-contaminated dialysate. Calcium concentrations in the hair of nondialyzed and dialyzed patients were higher than in the controls. Plasma zinc concentrations in all the patients were lower than the controls, and the concentrations in hemofiltered patients were lower than in the dialyzed patients.

Salivary urea nitrogen as an index to renal function: a test-strip method

To investigate the feasibility of using salivary urea nitrogen as an index of renal glomerular filtration rate, we developed and applied a new analytical system consisting of a urease-containing test strip and an automatic reflectance spectrometer. The concentrations of urea nitrogen so determined correlate well (r = 0.93) with concentrations in serum. These preliminary data suggest that our method can be used routinely as a simple and reliable means of detecting abnormalities of renal function.

Salivary urea nitrogen as an index to renal function: a test-strip method

To investigate the feasibility of using salivary urea nitrogen as an index of renal glomerular filtration rate, we developed and applied a new analytical system consisting of a urease-containing test strip and an automatic reflectance spectrometer. The concentrations of urea nitrogen so determined correlate well (r = 0.93) with concentrations in serum. These preliminary data suggest that our method can be used routinely as a simple and reliable means of detecting abnormalities of renal function.

Muscarinic cholinergic receptors of the convulsive strain (E1) mouse

The biochemical characteristics of the muscarinic acetylcholine receptors were studied on the E1 strain mouse brain by the binding assay using [3H]1- quinuclidinyl benzylate. Scatchard analyses showed that the receptor density (Bmax) of the hippocampus significantly decreased by 26.4% and the affinity (Kd) increased by 18.8% in E1(+) compared to dd-Y. It is suggested that this hippocampal subsensitivity found in E1(+) mouse might be strain-specific, because repeated megimide convulsions failed to produce the same down regulation.

Cysteine sulfinic acid in the central nervous system: specific binding of [35S]cysteic acid to cortical synaptic membranes--an investigation of possible binding sites for cysteine sulfinic acid

Specific binding sites for cysteine sulfinic acid, an excitatory amino acid, in crude synaptic membrane fractions of rat cerebral cortex were examined, using L-[35S]cysteic acid as a ligand. Two specific binding systems of [35S]cysteic acid were found, one Na+-dependent and the other Na+-independent. The Na+-independent specific binding of [35S]cysteic acid was saturable, with a Kd of 474 nM and Bmax of 3.29 pmol/mg protein. The binding was optimal at pH 7.4 and at 37 degrees C. Treatment of the membranes with proteases, concanavalin A, or Triton X-100 markedly reduced the binding. Of various compounds related to cysteic acid, L-cysteine sulfinic acid was the most effective competitor of this binding. These results indicate the existence of an Na+-independent specific binding site for cysteic acid in the synaptic membrane of rat cerebral cortex, which may be different from that for glutamate. Possible involvement of cysteine sulfinic acid as an endogenous ligand for this binding site is discussed.

Cysteine sulfinic acid in the central nervous system: uptake and release of cysteine sulfinic acid by a rat brain preparation

Uptake and release of cysteine sulfinic acid by synaptosomal fractions (P2) and slices of rat cerebral cortex were investigated. The P2 fraction had a Na+-dependent high-affinity uptake system for cysteine sulfinic acid (Km, 12 microM), which was restricted to the synaptosomes. High-affinity uptake of cysteine sulfinic acid was competitively inhibited by glutamate, aspartate, and cysteic acid. None of the various centrally acting drugs tested specifically inhibited this transport system. Release of [14C]cysteine sulfinic acid from preloaded cortical slices or P2 fractions was examined by a superfusion method, which avoided reuptake of released [14C]cysteine sulfinic acid. High K+ (56 mM) and veratridine (10 microM) stimulated the release of cysteine sulfinic acid from slices and the P2 fraction in a partly Ca2+-dependent manner. Diazepam at concentrations of 10 and 100 microM markedly inhibited the stimulated release, but not the spontaneous release, by cortisol slices. On the contrary, it had no effect on the stimulated release of cysteine sulfinic acid from the P2 fraction.

Developmental alteration in RNA metabolism of E1 mouse brain

The contents of brain RNA rose rapidly until 14 days after birth and then dropped. They were lower in the E1 than in the non-convulsive mice between 56 and 100 days of life. The contents of acid-soluble UMP and their specific radioactivities, three hours after an intracranial injection of [3 H]-orotic acid, were not different in the same age of E1 and non-convulsive mouse brains. From four to 20 days after birth, the specific and relative specific radioactivities, representing the ratio of brain RNA synthesis, of the E1 mice were lower than those of the non-convulsive strains, while the E1 mice, applying convulsions once a week, exhibited higher values during the periods from 56 to 100 days of age as compared with the non-stimulated E1 or non-convulsive strains.

Superiority of hemofiltration to hemodialysis for treatment of chronic renal failure: comparative studies between hemofiltration and hemodialysis on dialysis disequilibrium syndrome

A significantly lower incidence of DDS, hypotension, and impending shock was found during and after hemofiltration as compared with conventional hemodialysis. Hemofiltration, in contrast to hemodialysis, showed less decrease of circulating plasma volume, mild change in plasma osmolality without red cell swelling, better compensation of acidosis despite less uptake of acetate, more stable PCO2 during the procedure, less paradoxical acidosis in cerebrospinal fluid, and a lower urea concentration gradient between cerebrospinal fluid and plasma. These phenomena might be explained by better mass transfer between compartments bithin the body during hemofiltration. Mass transfer from the intracellular as well as the extracellular space to circulating plasma occurred more rapidly and smoothly during HF than during HD. HF is preferable to HD in patients with severe cardiovascular complications such as hypertension, as well as hypotension and cardiac failure, and in those subject to DDS during HD. Accordingly, hemofiltration therapy promises patients more comfortable and more stable treatment of chronic uremia.

Effect of ethanol on taurine concentration in the brain

The taurine concentration in the brain was decreased in ethanol-dependent rats, but returned to normal soon after withdrawal of ethanol. It was not affected by acute ethanol administration.

Increase of brain taurine contents of E1 mice by physiological stimulation

We determined the effect of physiological stimulation on taurine contents in three regions (cerebral cortex, brain stem and cerebellum) of the brain of E1 mice, a genetically epileptic strain. Taurine contents in all regions of the brain increased significantly at the onset of convulsions, as induced by tossing the animals up many times. Levels in the cerebral cortex and cerebellum increased markedly in the early stage of the stimulation, yet convulsion did not occur. Taurine contents in the cerebral cortex and brain stem returned to the resting level with 30 min after the onset of convulsions, while levels in the cerebellum remained high for 3 hr. Concentration of taurine in the plasma also increased with the onset of convulsions. On the other hand, taurine administration increased the threshold of convulsion by the stimulation in E1 mice.

Effects of thyroid deficiency at birth on deoxyribonucleic acid synthesis and deoxythymidine kinase activity in the developing rat brain

In thyroid deficiency at birth, the endogenous pool sizes of cellular dTTP did not change much in the cerebellum, cerebrum and brain stem at the whole ages studied, but the specific radioactivities of dTTP, at 2 hours after the subcutaneous injection of [3H]-thymidine, apparently increased only in the cerebellum on the 14th and 21st days as compared with the normal controls. The highest rate of DNA synthesis in vivo, expressed in terms of the specific radioactivity ratio of DNA to dTTP, was observed at the four-day-old normal rat cerebellum, and in the thyroid deficiency it appeared to shift between seven and 14 days of age. On the other hand, no apparent effects of thyroid deprivation on the rates of both the cerebrum and brain stem were found. The results suggest that a temporal alteration of DNA synthesis as well as thymidine metabolism occurred by thyroid deficiency was confined to the cerebellum in the early postnatal development of rats. Indeed, cerebellar thymidine kinase activity, related to DNA synthesis, also displayed a concomitant delay in thyroid deficiency to the characteristic age-dependence of DNA synthesis. No significant difference between normal and thyroidectomized rats was revealed in this respect on both the cerebrum and brain stem throughout the experimental periods.

Effects of neonatal thyroidectomy on thymidine metabolism and deoxyribonucleic acid synthesis in the developing rat cerebellum

Thyroid deficiency at birth caused a temporal decrease of the DNA content in rat cerebellum during the periods from 7 to 21 days of life as compared with the normal. At 2 h following the subcutaneous injection of [3H]-thymidine, the specific radioactivity of cellular dTTP in thyroid deficient rats was apparently increased on the 14th and 21st days, although the endogenous pool sizes of dTTP did not significantly differ between the normal and thyroidectomized rats throughout the entire ages studied. The ratio of incorporation of thymidine into cerebellar DNA was initially determined by the specific radioactivity and then expressed as the ratio of [3H]-DNA to [3H]-dTTP, the relative specific radioactivity of DNA. The age peak of incorporation occurred at 7 days in the normal; on the other hand, the specific activity of DNA in thyroid deficiency attained a maximum at 14 days and the relative specific activity appeared to be prolonged up to 14 days. The corresponding changes were observed in the formation of dTTP, suggesting that a transient retardation of cerebellar DNA synthesis taking place by neonatal thyroidectomy may be in part attributable to the variance of phosphorylation of thymidine. Indeed, thymidine kinase activity that regulated salvage pathway for DNA synthesis displayed a parallel variation in thyroid deficiency to characteristic age dependence of DNA synthesis.