Specificity for various imino-acid-residues of a proline-specific dipeptidylcarboxypeptidase from a Streptomyces species.

A proline-specific dipeptidylcarboxypeptidase, which removes diproline from the C-terminus of the proline-containing peptides, such as Boc-Pro-Pro-Pro-Pro and Leu-Pro-Pro-Pro-Pro-Pro, has recently been purified from a Streptomyces sp. The specificity of the enzyme for various imino acid-containing synthetic peptide substrates was further studied. The peptides with proline, hydroxyproline, or dehydroproline at the P2' position were found to be good substrates, while those with pipecolic acid, D-proline or other usual amino acids at the P2' position were scarcely hydrolyzed. The peptides with proline, dehydroproline, pipecolic acid, or N-methyl-alanine at the P1' position were well-hydrolyzed, while those with hydroxyproline or D-proline at the P1' position were not hydrolyzed. Utilizing this high specificity for imino acids, Boc-Pro-Pro-Pro-Pro was synthesized by the enzyme using Boc-Pro-Pro as the acidic component and Pro-Pro as the basic component.

Serum N-acetyl-beta-D-glucosaminidase activity in predicting the development of hypertension.

We conducted a prospective study in residents of a small farming community in southwestern Japan to determine whether elevated serum N-acetyl-beta-D-glucosaminidase (NAG) activity would predict future hypertension. The 505 normotensive subjects (blood pressure, < 140/90 mm Hg; mean age, 52 +/- 12 years) were reexamined after 7 years; 111 (22%) had become hypertensive (defined as blood pressure > or = 140/90 mm Hg and/or taking antihypertensive medication at follow-up). After adjustment for age and sex, the development of hypertension was significantly related to body mass index (P < .002), the sum of skinfolds (P < .001), baseline blood pressure (P < .0001), serum cholesterol (P < .01), serum uric acid level (P < .0001), and serum NAG activity (P < .005). Elevated NAG activity showed an independent relationship to future hypertension (P < .005) after adjustments for age, sex, baseline blood pressure (systolic, diastolic, or mean), uric acid level, and the sum of skinfolds. Therefore, elevated serum NAG activity was an effective indicator of future hypertension, and it might therefore be related to functional and/or structural changes in the cardiovascular system.

Chronic L-arginine administration attenuates cardiac hypertrophy in spontaneously hypertensive rats.

Nitric oxide inhibits proliferation and migration of vascular smooth muscle cells and contractility of cardiomyocytes in vitro. In spontaneously hypertensive rats (SHR), evidence suggests intrinsic abnormalities of the L-arginine-nitric oxide axis, such as low cGMP-dependent protein kinase in the heart and abnormal L-arginine metabolism. To investigate the in vivo effect of L-arginine on cardiac hypertrophy, 30 SHR and 30 Wistar-Kyoto rats (WKY) were randomly grouped to receive L-arginine (7.5 g/L in drinking water) or vehicle for 12 weeks. L-Arginine treatment did not affect body weight or arterial pressure in either strain. In vehicle-treated animals, the heart/body weight ratio was significantly higher in SHR than in WKY (P < .01). L-Arginine treatment decreased the heart/body weight ratio in SHR (P < .05) but did not affect it in WKY. Expression of skeletal alpha-actin mRNA, known to be expressed in the hypertrophied myocardium, was attenuated in L-arginine-treated SHR compared with vehicle-treated SHR. Cardiac cGMP content and nitrate/nitrite content were less in SHR than WKY. L-Arginine treatment increased these levels only in SHR, suggesting enhanced nitric oxide production. Thus, chronic L-arginine administration attenuated cardiac hypertrophy independently of blood pressure and increased myocardial content of cGMP and nitrate/nitrite. Our results suggest that abnormality of the cardiac L-arginine-nitric oxide axis may play an important role in the pathogenesis of cardiac hypertrophy in SHR.

Hypertension induced by nitric oxide synthesis inhibition is renal nerve dependent.

Recent studies have indicated that chronic administration of N omega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, produces marked hypertension. Although the mechanism of this form of hypertension is not well understood, several studies have demonstrated that sympathetic nerve activity is at least acutely elevated after L-NAME administration. To evaluate the potential role of the renal sympathetic nerves in L-NAME-induced hypertension, we compared the blood pressure response to L-NAME in four groups of Sprague-Dawley rats (n = 8 each): (1) sham-operated vehicle-treated, (2) sham-operated L-NAME-treated, (3) denervated vehicle-treated, and (4) denervated L-NAME-treated. After renal denervation or sham surgery, L-NAME was added to the drinking water (70 mg/100 mL) for 4 weeks, and arterial pressure was measured weekly by the tail-cuff method. L-NAME treatment caused a progressive increase in arterial pressure in sham-operated rats, rising to 154 +/- 6 mm Hg by week 4 of treatment compared with 115 +/- 2 mm Hg in the vehicle-treated sham-operated group (P < .005). In contrast, the development of hypertension was significantly delayed and attenuated in renal-denervated rats treated with L-NAME. The results of our study suggest that L-NAME-induced hypertension may be partly mediated by or is at least dependent on the integrity of the renal nerves.

Hyperinsulinaemia as a predictor of hypertension: an 11-year follow-up study in Japan.

OBJECTIVE: To examine the hypothesis that hyperinsulinaemia is associated with the development of borderline hypertension or hypertension. DESIGN: Blood pressure status in non-obese normotensives (< 140/90 mmHg, n = 135) people were re-examined after 11 years after the baseline examination. Participants were selected from a 1981 population-based health examination and had a high blood glucose level or more than a trace of glucose in their urine. Out of 319 people recruited for further examination of glucose tolerance status, 135 normotensive participants with body mass index < 26 kg/m2 and without diabetes according to World Health Organization criteria were re-examined at the follow-up survey. RESULTS: Sixty-two (46%) out of 135 normotensive participants were hypertensive (defined as blood pressure > or = 140/90 mmHg) or receiving antihypertensive medication (n = 8) at the follow-up survey. Significant associations between the development of hypertension and baseline parameters were observed for systolic and diastolic blood pressure, serum triglycerides, high-density lipoprotein (HDL)-cholesterol, fasting and 60 min post-load insulin levels, and the sum of insulin concentrations from fasting to 180 min after glucose challenge after adjustments for age and sex. Odds ratios (95% confidence intervals) for the future development of hypertension between the highest and the lowest tertiles of insulin levels were 4.06 (1.40-11.76) for fasting insulin, 4.25 (1.45-12.45) for 60 min post-glucose load insulin, and 3.88 (1.34-11.20) for the sum of insulin concentrations, after adjustment for age, sex, systolic blood pressure, body mass index and alcohol consumption. Further adjustments for serum triglycerides and serum creatinine did not affect the insulin-hypertension relationship. CONCLUSION: The present study suggests that hyperinsulinemia is significantly related to the development of hypertension in non-obese and non-diabetic Japanese people.

Ion heating and high-energy-particle production by ion-cyclotron heating in the large helical device

Ion-cyclotron heating was applied to the Large Helical Device. When the proton-cyclotron resonance was near the saddle point of the magnetic field-strength plane, strong ion-cyclotron damping occurred. Under these conditions efficient plasma heating was achieved for more than one minute. A high-energy ion tail was observed, and the effective tail temperature was determined by a balance between the wave acceleration and the electron-drag relaxation. There was no apparent sign of particle orbit loss effect in the investigated density range of 0.8-1.3x10(19) m(-3).

Renal depressor mechanisms of physical training in patients with essential hypertension.

To clarify characteristics of the patients in whom exercise training lowers blood pressure and to elucidate the mechanisms by which exercise training lowers blood pressure, we evaluated 24-h blood pressure, glomerular filtration rate (GFR), renal blood flow (RBF), filtration fraction (FF), plasma renin activity (PRA), plasma aldosterone concentration (PAC), plasma norepinephrine concentration (PNE), and incremental area of insulin/glucose (sigmaI/sigmaG) during 75 g oral glucose tolerance test, and assessed arterial baroreceptor function (BSI) before and after a 3-week exercise training program (four 6-min sessions daily at 75% VO2 max). Patients were classified as responders (n = 15) if they showed statistically significant reduction in the multiple comparison of 24-h mean arterial pressure (MAP), or as nonresponders (n = 15) if they did not. Although there were no significant differences between responders and nonresponders in age, weight, MAP, GFR, RBF, RPF, FF, PNE, sigmaI/sigmaG, or BSI before exercise, renal vascular resistance (RVR; P < .05), PRA (P < .05), and PAC (P < .05) were significantly higher in responders than in nonresponders. The fractional excretion of sodium (FENa) (P < .05) were significantly lower in responders than in nonresponders. After exercise training, FF (P < .01), RVR (P < .05), PNE (P < .05) PRA (P < .01), and sigmaI/sigmaG (P < .05) decreased significantly only in responders. The decrease in MAP significantly correlated with the reductions in FF (r = 0.46, P < .05), PNE (r = 0.52, P < .01) and RVR (r = 0.40, P < .05). Thus, in patients who have higher RVR and PRA, exercise training lowered blood pressure in parallel to a reduction in RVR associated with decreases in sympathetic tone and improvement of insulin resistance. Our results suggest that exercise-induced changes in renal hemodynamics may contribute to the reduction in blood pressure in these patients.

Purification and characterization of a novel dipeptidyl carboxypeptidase from a Streptomyces species.

An extracellular protease derived from the culture broth of a microorganism, a Streptomyces species, produced Boc-Pro-Pro and diproline from Boc-Pro-Pro-Pro-Pro. The enzyme was purified 726-fold, with a yield of 2.6%, by ammonium sulfate fractionation, ion-exchange chromatography, and gel filtration chromatography. The molecular weight of the enzyme was determined to be 65,000 by gel filtration and 70,000 by SDS-PAGE. The enzyme released a C-terminal dipeptide from peptide substrates having a C-terminal proline and a penultimate proline or alanine residue, but did not hydrolyze angiotensin I or bradykinin. When the enzyme hydrolyzed Leu-Pro-Pro-Pro-Pro-Pro, it produced Leu-Pro-Pro-Pro and Pro-Pro before producing Leu-Pro. The enzyme thus seems to be a kind of dipeptidyl carboxypeptidase, its substrate specificity being very different from that of the well known dipeptidyl carboxypeptidases [EC 3.4.15.1] such as the angiotensin-converting enzyme.

Gln27Glu and Arg16Gly polymorphisms of the beta2-adrenergic receptor gene are not associated with obesity in Japanese men.

The beta2-adrenergic receptor (beta2AR), beta3AR, or uncoupling protein 1 (UCP1) may play a pathogenic role in obesity. In Swedish Caucasians, a polymorphism at codon 27 (Gln27Glu) of the beta2AR gene was shown to be associated with obesity, but no such association was shown for a polymorphism of codon 16 (Arg16Gly). Thus, we investigated whether these polymorphisms contribute to obesity in 210 Japanese men. The frequencies of the Gln27Glu and Arg16Gly polymorphisms were 0.05 and 0.48, respectively, and there was no association with obesity. A strong linkage disequilibrium between the Gln27Glu and Arg16Gly polymorphisms was shown, but there was no apparent additive effect on the clinical or metabolic characteristics. Our results suggest that the Gln27Glu and Arg16Gly polymorphisms of the beta2AR gene are not a major contributing factor to obesity in Japanese men.

Tumor necrosis factor-beta gene NcoI polymorphism decreases insulin resistance in Japanese men.

Given that the NcoI polymorphism of the tumor necrosis factor-beta (TNF-beta) gene has been shown to be associated with tumor necrosis factor-alpha (TNF-alpha) secretory capacity, we know that this TNF-beta gene polymorphism may influence insulin resistance. In Caucasians, 2 polymorphisms of the TNF-alpha promoter region (positions -308 and -238) have been reported to be associated with insulin resistance. Thus, we investigated how genetic variation in the TNF-beta and TNF-alpha genes was associated with insulin resistance in 211 Japanese men. The frequency of the TNF-beta gene polymorphism was 0.41, and insulin resistance, estimated by homeostasis model assessment (HOMA), was significantly lower in variant homozygotes versus wild-type allele. The frequencies of the -308 and -238 polymorphisms were 0.01 and 0.02, respectively, and these polymorphisms were not associated with insulin resistance. Our results suggest that the TNF-beta gene polymorphism decreases insulin resistance, and that the -308 and -238 polymorphisms of the TNF-alpha promoter region are not a major contributing factor to insulin resistance in Japanese men.

Phenotypic characterization of the beta3-adrenergic receptor mutation and the uncoupling protein 1 polymorphism in Japanese men.

The Trp64Arg mutation of the beta3-adrenergic receptor (beta3AR) gene and A to G polymorphism of the uncoupling protein 1 (UCP1) gene are reported to be associated with weight gain, and both have been shown to have an additive effect on weight gain in Caucasians. Racial differences have also been noted in the beta3AR mutation; however, the effect of UCP1 polymorphism on body weight is not obvious in the Japanese. Thus, we investigated the association of genetic variations in beta3AR and UCP1 genes and the additive effects of these two genes in 214 Japanese men. The frequency of the Trp64Arg allele was 0.19, and serum triglyceride was significantly higher in Arg64 homozygotes versus Trp64 homozygotes. The frequency of the G allele was 0.51, and the body mass index (BMI) was significantly higher in subjects with the G allele (GG homozygotes and AG heterozygotes) versus those without it (AA homozygotes). The beta3AR mutation and UCP1 polymorphism were not found to have additive effects, and they were not related to glucose tolerance patterns and insulin resistance. Our results suggest that the beta3AR mutation is associated with hypertriglyceridemia and the UCP1 polymorphism may be a weak contributing factor to obesity in Japanese men.

Variation of the fatty acid binding protein 2 gene is not associated with obesity and insulin resistance in Japanese subjects.

An alanine to threonine substitution at codon 54 of the fatty acid binding protein 2 (FABP2) gene has been associated with insulin resistance in Pima Indians and with obesity in aboriginal Canadians. We investigated whether this polymorphism contributes to obesity and insulin resistance in 258 Japanese subjects. Thirty-six subjects (13.9%) were homozygous for the Thr54 allele, 106 (41.1%) were heterozygous for the Ala54/Thr54 allele, and 116 (45.0%) were homozygous for the Ala54 allele. The frequency of the Thr54 allele was 0.34 and did not differ significantly between men and women. The incidence of non-insulin-dependent diabetes mellitus (NIDDM) was not different among the three genotypes. The variation at codon 54 of the FABP2 gene was not associated with obesity, hypertension, dyslipidemia, hyperuricemia, or hyperinsulinemia. These results suggest that the polymorphism at codon 54 of the FABP2 gene is not a major contributing factor to obesity and insulin resistance in Japanese subjects.

Structural identification of a heterocyclic compound implicated in the Spanish toxic oil syndrome.

The compound 1-phenyl-5-vinylimidazolidine-2-thione was previously reported to be the causative agent in the outbreak referred to as Spanish toxic oil syndrome. X-ray crystallography, together with nuclear magnetic resonance and infra-red spectroscopy, now show the correct structure of this compound to be N-(5-vinyl-1,3-thiazolidin-2-ylidene)phenylamine (5-VTPA). Data for the structural characterization of 5-VTPA and the closely related isomer N-(4-vinyl-1,3-thiazolidin-2-ylidene)phenylamine are reported.

Depressor effect by exercise training is associated with amelioration of hyperinsulinemia and sympathetic overactivity.

OBJECTIVE: In hypertensive subjects, exercise training is a therapeutic modality that not only lowers blood pressure but also corrects metabolic abnormality, such as hyperinsulinemia. Insulin causes sympatho-excitation via the modification of baroreflex, norepinephrine release, or central sympathetic outflow. However, the link between neural and metabolic changes by exercise training in hypertensive patients remains unknown. The aim of this study was to examine whether or not the blood pressure lowering effect of exercise training is associated with the improvement of insulin sensitivity in conjunction with the inhibition of sympathetic tone in hypertensive patients. METHODS: We evaluated plasma insulin levels, arterial baroreflex function and humoral parameters before and after exercise training. Twenty-nine patients with essential hypertension under hospitalization participated in the study. Before and after three weeks of exercise training (75% max VO2, 6 min, q.i.d.), 24-hour blood pressure recordings, arterial baroreflex function testing and 75 g glucose tolerance tests were conducted. Area under the curve of insulin (sigma insulin) to glucose load was calculated as an index of hyperinsulinemia. RESULTS: Three weeks of exercise training decreased the 24-hour mean arterial pressure, heart rate and sigma insulin, and improved barorefiex function. There was a significant correlation between the reduction of arterial pressure and the change in sigma insulin. Furthermore, the reduction of sigma insulin was correlated with the improvement of baroreflex function and with the decrease in heart rate. CONCLUSIONS: Exercise training lowered the arterial pressure, with parallel changes in heart rate, baroreflex function and insulin resistance. The correction of sympathetic overactivity was closely associated with the amelioration of hyperinsulinemia. Our results suggest that the improvement of neuro-metabolic factors may be involved in the depressor effect caused by exercise training.

Tc-99m tetrofosmin. A new diagnostic tracer for parathyroid imaging.

A 42-year old woman with hyperparathyroidism had a CT scan that was suggestive of a small nodular lesion in the left lower neck. Tc-99m sestamibi and Tc-99m tetrofosmin parathyroid imaging were performed 10 minutes and 2 hours after tracer injection. Early imaging with Tc-99m sestamibi demonstrated thyroid and focal uptake in the left lower neck. On delayed imaging, findings suggested a parathyroid adenoma. Imaging with Tc-99m tetrofosmin demonstrated similar findings. The abnormal parathyroid gland was an adenoma.

Acute-phase kidney transplants show early peak appearance in Tc-99m DTPA renogram.

Kidney transplants have been evaluated using a radionuclide technique to determine perfusion index (PI), mean transit time (MTT), and the parameters in renogram curve (Tmax, T1/2, and T2/3). The values for Tmax, T1/2, and T2/3 were also determined in normal volunteers. The results indicated that the Tmax value was less than 2 minutes, one week after transplantation. The other data were within normal limits. The appearance of Tmax was very early. The early time activity curve (TAC) was quite similar to the blood disappearance curve, TAC did not have the functional-phase, so-called, 2nd-phase. These data suggested that there could be an abnormality of the renal circulation in the transplanted kidney. The suggestion offers the new finding in a field of renal transplantation using radionuclide technique.

[Studies of cell-mediated immunity in mesangial proliferative glomerulonephritis--IgA nephropathy and non-IgA nephropathy].

In order to clarify the abnormalities of cell-mediated immunity in patients with mesangial proliferative glomerulonephritis [IgA nephropathy (IgA N) and Non-IgA nephropathy (Non-IgA N)], lymphocyte subsets were analysed by using monoclonal antibodies with flow cytometric two-color analysis and interleukin-2 (IL-2) production from lymphocytes of the patients was measured by ELISA system. A markedly decreased percentage (11.6 +/- 10.5%) of CD4+ 45R+ cells was found in the patients with IgA N when the results were compared with the normal controls (20 +/- 6%) (P less than 0.01). No difference was found between patients with IgA N and the controls as to the percentage of CD4+ 45R-, CD8+, 11+ and CD8+ 11- cells, respectively. Patients with Non-IgA N also showed a significantly decreased percentage of CD4+ 45R+ cells (10.9 +/- 6.5%), while CD8+ 11+ cells was parallely lowered (7.4 +/- 5%) in compared with the controls (10 +/- 4%). The percentage of HLA-DR positive cells was found to be increased in the patients with both IgA N and Non-IgA N, although the antigen bearing cells were reduced after stimulation with Concanavalin-A (Con-A). No difference in IL-2 production from lymphocyte of both patients groups and the controls cultured with Con-A was found. These results suggested that a deficiency of suppressor inducer T cells played a part of the pathogenesis of IgA N and Non-IgA N.

[Bronchial asthma due to Stronger Neo-Minophagen C].

A 24-year-old woman who visited our hospital because of urticaria had a bronchial asthma attack about 5 min. after receiving Stronger Neo-Minophagen C (SNMC) intravenously. A skin test for SNMC and its components (glycyrrhizin, L-cystein, aminoacetic acid, and sodium sulfite) was positive for SNMC and borderline for sodium sulfite after 15 min. A skin test for mixtures of L-cystein and sodium sulfite was also positive. Inhalation provocation tests for SNMC and mixtures of L-cystein and sodium sulfite were positive after 5 min. An inhalation provocation test for sulpyrin was also positive. The patient's bronchial asthma attack was ascribed to SNMC. Type I allergy to mixtures of L-cystein and sodium sulfite was the suspected cause.