Polymerization of allyl esters of unsaturated acids, 12. Cyclopolymerization of methyl 2-methylallyl fumarate

The kinetics of radical-initiated cyclopolymerization of methyl 2-methylallyl fumarate (MMAF) was investigated and compared with the polymerization results of allyl methyl fumarate (AMF). In the former, the extent of cyclization and five-membered ring formation were enhanced. The cyclization constants K_A and K_V, the ratio of the rate constant of the unimolecular cyclization reaction to that of the bimolecular propagation reaction of the uncyclized 2-methylallylic and fumaric radicals, were estimated to be 3,1 and 3,0 mol · dm^?3, respectively. On the basis of these results the formation mode and the sequence distribution of the structural units of the polymer produced are discussed in detail; the low probability for fumaric vinyl addition and high probability for the succession of cyclic structures are calculated for poly(MMAF) as opposed to those of poly(AMF). The cyclopolymerizability and five-membered ring formation are enhanced at elevated temperature. These results are discussed from the standpoint of the steric effect on cyclopolymerizability.     

A Pharmacokinetic Study of Clomipramine in Regions of the Brain

Abstract: The pharmacokinetic profiles of clomipramine (CMP) and the serial changes of its concentration in specific brain regions were investigated in rats after an acute treatment with intravenous CMP (10 mg/kg). The CMP concentrations in plasma declined triexponentially and fitted a three-compartment open model. The brain to plasma concentration ratio showed a constant value, 22.2 ± 4.9, 30 minutes after the injection. Regional brain differences in the CMP distribution and accumulation were also found. Four hours after the injections, the hippocampus was found to have the highest drug concentration, and the concentrations in this region were in the following order; thalamus, striatum, amygdala, cortex > pons + medulla oblongata > hypothalamus, bulbus olfactorius + septum, mesencephalon > cerebellum. Particularly, unique kinetics were observed in the cortex, amygdala and hippocampus.     

Repeat tricuspid valve replacement for acquired valvular heart disease: Report of a case

(Received for publication on May 30, 1997; accepted on Nov. 6, 1997)     

Quick assay of serum HBs antibody levels using latex agglutination-integrating sphere turbidimetric assay (ISTA)

A method for determining serum HBs antibody applying the principle of integrating sphere turbidimetric assay (ISTA) by latex agglutination was developed. The minimum detectable level of HBs antibody by this method is 12.5 IU/L, indicating that this method is 3 times or more sensitive with better reproducibility and specificity than the passive hemagglutination (PHA) method. With a cut-off level of 25 IU/L, the possible highest simultaneous reading by this method was 1,000 IU/L Serum HBs antibody can be readily measured in 10 or so minutes by this method if a fully automated EL-1000 analyzer is used. This rapid and simple method for determining serum HBs antibody will be useful not only clinically, but also in preventive medicine. © 1993 Wiley-Liss, Inc.     

A novel missense mutation of exon 3 in the type A human natriuretic peptide receptor gene: possible association with essential hypertension.

The natriuretic peptide (NP) family is involved in regulation of blood pressure and fluid volume. We recently characterized the exon/intron organization of the human type A NP receptor (hNPRA) gene. The aim of this study was to isolate the genetic markers according to the organization of this gene, and to study the association between this gene and essential hypertension. Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, we identified a novel missense mutation, M3411, consisting of a methionine (ATG) to isoleucine (ATC) substitution at nucleotide 1023 in exon 3. Computer-aided three-dimensional structural analysis suggested that M341 exists in the loop between two alpha-helices, and that the mutation may influence receptor activities by altering the conformation of the alpha-helices. We performed an association study of the mutation in 210 essential hypertension (EH) patients and 210 normotensive controls. The overall distribution of alleles was not significantly different between the control and EH groups. However, the C/C homozygous genotype was found only in the EH group. The ratio of plasma brain natriuretic peptide (BNP)/mean blood pressure of the C/C genotype was significantly higher than that of the G/G genotype or the G/C genotype. We conclude that the significance of homozygous M3411 mutation in exon 3 is worth investigating for its possible association with EH.     

Acute Effect of Anticonvulsants on Amygdaloid Kindled Seizures Induced with Low-Frequency Stimulations

Acute effects of several antiepileptic drugs on low-frequency amygdaloid-kindled seizures were assessed. The number of stimulating pulses required for the provocation of epileptic afterdischarge (pulse-number threshold, PNT) was used as an indicator for the seizure-generating threshold. The duration of epileptic afterdischarge (AD duration) was used as an indicator for the severity of the induced seizures. Phenytoin (PHT) and carbamazepine (CBZ) reduced AD duration more than did elevating PNT. Conversely, phenobarbital (PB) and diazepam (DZP) elevated PNT more than did reducing AD duration. Weak effects on the two indicators, valproic acid (VPA) and ethosuximide (ESM), were observed. Low-frequency kindling may be a useful experimental model of epilepsy in drug-assessments.     

Acute Effect of TRH, Fhmarizine, Lithium and Zotepine on Amygdaloid Kindled Seizures Induced with Low-Frequency Stimulation

Abstract: We assessed the acute effects of various drugs on amygdaloid kindled seizures induced with low-frequency stimulations. We used the number of stimulating pulses required for the induction of epileptic afterdischarge (pulse-number threshold; PNT) as an indicator of the seizure generating threshold and the duration of induced seizures (AD duration; ADD) as an indicator of the seizures. TRH increased the PNT without affecting the ADD at a high dose (1.2 mg/kg). Flunarizine decreased the PNT and ADD simultaneously at a high dose (50 mg/kg). Lithium increased the PNT without affecting the ADD at two doses (100 mg/kg, 200 mg/kg). Zotepine decreased the PNT without affecting the ADD at two doses (8 mg/kg, 16 mg/kg). We propose that the technique of low-frequency kindling is a useful experimental model in assessing the effects of antipsychotic or antiepileptic drugs on the excitability of the limbic regions.