Prevention of pulmonary embolism by a foot sole pump

We carried out a prospective, randomised study of 62 patients to determine the efficacy of a foot sole pump (the A-V Impulse System) for the prevention of pulmonary embolism (PE) after hip surgery. PE was assessed by pulmonary perfusion scintigraphy before and after operation. We defined a PE as any new scintigraphic defect which was larger than a bronchopulmonary segment. The incidence of PE was 55% in the control group and 21% in the treatment group. The foot sole pump significantly reduced the incidence of PE (p = 0.008) and we encountered no side-effects from its use.

Riluzole (2-amino-6-trifluoromethoxy benzothiazole) attenuates MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) neurotoxicity in mice

The protective effects of 2-amino-6-trifluoromethoxy benzothiazole (riluzole), a Na(+) channel blocker with antiglutamatergic activity were investigated in the model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced depletion of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels in mice. The mice were injected intraperitoneally (i.p.) with four administrations of MPTP (10 mg/kg) at 1 h intervals and then the brains were analyzed at 3 and 7 days after the treatments. Dopamine, DOPAC and HVA levels were significantly decreased in the striatum 3 days after MPTP treatments. Riluzole dose-dependently antagonized the MPTP-induced decrease in dopamine, DOPAC and HVA levels in the striatum. MPTP treatment also caused a severe decrease in the amount of nigral tyrosine hydroxylase protein (TH) and microtuble-associated protein 2 (MAP 2) and produced a marked increase in the striatal glial fibrillary acidic protein (GFAP). Our immunohistochemical study with TH and MAP 2 staining showed that riluzole can protect against MPTP-induced neuronal damage in the substantia nigra. Furthermore, riluzole markedly increased the striatal GFAP-positive astrocytes 3 days after MPTP treatments. These results suggest that riluzole is effective against MPTP-induced neurodegeneration of the nigrostriatal dopaminergic neuronal pathway. Our findings also may provide a rationale for the identification of astrocytes as a prominent target for the development of new therapies of Parkinson's disease.

Inhibition of K(+)-evoked release of rat striatal 5-hydroxytryptamine by an atypical antidepressant: trazodone

Using microdialysis, extracellular concentrations of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined in the striatum of rats. In rats given trazodone, m-chlorophenylpiperazine dihydrochloride, or imipramine, the concentrations of 5-HT were unchanged. 5-HIAA in trazodone- or imipramine-treated rats, however, was respectively, decreased to 80 or 65% of preinjections levels. When the potassium concentration (K(+)) was increased up to 150 mmol/l in the perfusate, the concentrations of 5-HT increased to about ten times the basal levels in the rats given saline. In rats treated with trazodone, K(+)-evoked elevations of 5-HT were less than five times the basal level. Multiple trazodone administrations prolonged the duration of inhibition of 5-HT release. In rats treated with other drugs, the K(+)-evoked 5-HT release was not affected. These observations suggest that trazodone itself might reduce 5-HT neural transmission.

Serum leptin and lipids in patients with thyroid dysfunction

This work was undertaken to examine the relationship between thyroid hormone and serum leptin concentration. This study included 368 Japanese female subjects (27 were affected with pretreatment hyperthyroidism, 68 with hyperthyroidism during treatment, 19 with pretreatment hypothyroidism, 57 with hypothyroidism during treatment and 197 euthyroid control subjects) and 60 control male subjects. In the control group, serum leptin levels in males were lower than those recorded in females (mean +/- SD; 4.6 +/- 4.1 vs 9.5 +/- 6.4 ng/ml, p < 0.001). The leptin values correlated well with body mass index (BMI) and body fat mass (BFM) in both control male and female subjects (p < 0.001 for each). The serum leptin levels in pretreatment female patients with hyperthyroidism were significantly lower than those in the pretreatment patients with primary hypothyroidism and control female subjects (6.4 +/- 3.0 vs 9.7 +/- 6.3, 9.5 +/- 6.4 ng/ml; p < 0.05, 0.02, respectively), but after adjusting for BMI and BFM, the difference was mainly due to the significantly different BMI and BFM. Furthermore, serum leptin did not change significantly during the treatment in hyper and hypothyroidism. There was no correlation between serum leptin and thyroid hormones or lipids levels in female patients with thyroid disorders. Adiposity and gender were the major determinants of leptin concentration, but thyroid hormones did not appear to play any relevant role in leptin synthesis and secretion in human.

Limited urinary concentration and damaged tubules in rats with a syngeneic kidney graft

BACKGROUND

The underlying mechanisms of renal transplant dysfunction are poorly understood. There is little information on tubular function in kidney grafts. The cDNAs encoding kidney-specific cell surface proteins required for renal reabsorption of sodium (sodium cotransporter in thick ascending limb of Henle, rBSC1) and water (apical water channel in collecting duct, AQP2) have been recently identified. Since transcripts of these proteins are up-regulated in dehydration in association with maximal concentration of urine, we examined urinary concentrating ability and expression levels of mRNA of these proteins in kidney isografts.

METHODS

Male Sprague-Dawley rats underwent syngeneic renal transplantation or unilateral nephrectomy (UNX) and were deprived of water for 24 hours at six weeks after the operation when histological and functional compensation of the intact kidney was complete. Blood and urinary samples were collected before and after dehydration. The amount of rBSC1 or AQP2 mRNA was measured using competitive polymerase chain reaction (PCR) by inducing a point mutation at the middle of PCR product for rBSC1 or by deleting 180 bp from 780 bp PCR product for AQP2, respectively. The protein expression was examined by Western blot analysis.

RESULTS

Both groups of rats demonstrated the same levels of compensatory renal hypertrophy (approximately 60% weight increase) and plasma creatinine values. Histological examination revealed enlarged glomeruli and tubules, but no findings of ischemic damage, such as tubular atrophy or interstitial changes. Urinary concentration was noted in the UNX rats but not in rats with kidney grafts. Competitive PCR demonstrated that dehydration did not increase rBSC1 and AQP2 transcripts in rats with kidney transplantation. Immunoblot analysis confirmed that the marked increase of both rBSC1 and AQP2 proteins was noted only in the remnant kidney of dehydrated rats.

CONCLUSIONS

Rats with kidney isografts have a limited capacity to concentrate urine and, at the same time, fail to increase rBSC1 and AQP2 transcripts. This suggests that there is a prolonged damage of renal tubules by ischemia or denervation of the donor kidney, both of which are inevitable in the transplantation procedure.

A novel feature of the multistep phosphorelay in Escherichia coli: a revised model of the RcsC --> YojN --> RcsB signalling pathway implicated in capsular synthesis and swarming behaviour

In this study, we re-investigated the previously characterized RcsC (sensor His-kinase) --> RcsB (response regulator) phosphorelay system that is involved in the regulation of capsular polysaccharide synthesis in Escherichia coli. The previously proposed model hypothesized the occurrence of a direct phosphotransfer from RcsC to RcsB in response to an unknown external stimulus. As judged from the current general view as to the His --> Asp phosphorelay, this RcsC --> RcsB framework is somewhat puzzling, because RcsC appears to contain both a His-kinase domain and a receiver domain, but not a histidine (His)-containing phosphotransmitter domain (e.g. HPt domain). We thus suspected that an as yet unknown mechanism might be underlying in this particular His --> Asp phosphorelay system. Here, we provide several lines of in vivo and in vitro evidence that a novel and unique His-containing phosphotransmitter (named YojN) is essential for this signalling system. A revised model is proposed in which the multistep RcsC --> YojN --> RcsB phosphorelay is implicated. It was also demonstrated that this complex signalling system is somehow involved in the modulation of a characteristic behaviour of E. coli cells during colony formation on the surface of agar plates, namely swarming.

Nitric oxide synthase inhibitors cause motor deficits in mice

We investigated possible motor effects of 7-nitroindazole (7-NI), an neuronal nitric oxide synthase (nNOS) inhibitor, and N(G)-nitro-L-arginine methyl ester (L-NAME), an non-selective NOS inhibitor in mice using catalepsy and pole tests in comparison with dopamine D(2) receptor antagonist, haloperidol. We also studied the change in dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) contents of these compounds. The administration of 7-NI and L-NAME (40-160 mg/kg, s.c.) dose-dependently induced motor deficit in both catalepsy and pole tests. The motor deficit induced by 7-NI was more pronounced than the one produced by L-NAME. In contrast, haloperidol showed a marked motor deficit in mice. Haloperidol showed a marked motor deficit as compared with 7-NI and L-NAME. For dopamine, DOPAC and HVA contents, haloperidol exhibited a significant decrease in dopamine content and a significant increase in DOPAC and HVA content in the striatum. In contrast, 7-NI showed a significant increase in the striatal dopamine content. However, 7-NI had no significant change in the striatal DOPAC and HVA contents. On the other hand, no significant change in the striatal dopamine, DOPAC and HVA contents was observed in L-NAME-treated mice. The present study also showed that the motor deficit induced by 7-NI or L-NAME was significantly attenuated by the treatment with L-arginine. These results demonstrate that NOS inhibitors as well as dopamine D(2) receptor antagonist haloperidol can induce motor deficit in mice. The present study also suggests that the mechanism in the motor deficit caused by NOS inhibitors may be different from that in the motor deficit induced by haloperidol. Furthermore, our findings suggest that nNOS may play some role in control of motor behavior.

Genetic association between Alzheimer disease and the alpha-synuclein gene

alpha-Synuclein has been isolated as a component of amyloid in addition to the major A beta peptide in Alzheimer disease (AD). However, there are conflicting reports regarding the association of alpha-synuclein gene polymorphism with AD. Using a novel and common polymorphism in intron 3, we examined the relationship between AD and alpha-synuclein and apolipoprotein E (ApoE) genes in 183 Japanese AD patients and 210 controls. Carriers of the alpha-synuclein deletion (D) allele had a 2.2-fold increased risk of developing AD than noncarriers in women. The odds ratio for the ApoE epsilon 4 and the alpha-synuclein D allele was 11.4 in women. The results showed that the alpha-synuclein gene is associated with sporadic AD in women, independent of ApoE epsilon 4 status.

Decreased longevity in Japanese men, associated with low-molecular-weight apolipoprotein(a) phenotypes

Lipoprotein(a) [Lp(a)] is an established risk factor for atherosclerosis. High plasma Lp(a) concentrations are associated with low-molecular-weight (LMW) apolipoprotein(a) (apo a) phenotypes, which raises the question of whether LMW apo a phenotypes occur less frequently in the elderly. To assess this possibility, we studied apo A phenotype and allele frequencies in Japanese subjects > or = 80 years old (men:women = 40:34) in comparison with those <80 years old (men:women = 221:296). Significantly fewer LMW phenotypes and LMW alleles were observed in > or = 80 year old men compared with those < 80 years old: 2.5% versus 16.1% for the LMW phenotype frequency and 1.3% versus 9.7% for the LMW allele frequency (P<0.05, Fisher's exact probability test). Similar differences were not found in the women. Consistent with this, plasma Lp(a) concentrations were significantly lower in the men > or = 80 years old than in the younger group. These results indicate that LMW apo a phenotypes are associated with a shorter lifespan in men but not in women, possibly reflecting the higher susceptibility of men to atherosclerosis.

Polarization dependence of resonant X-ray emission spectra in early transition metal compounds

We calculate the polarization dependent spectra of resonant X-ray emission in TiF3, VF3 and Cr2O3, which have one, two and three 3d electron(s) in the ground state, respectively. We study the detailed mechanism of the spectral structures, comparing with a previous result of TiO2. Then we discuss systematically the difference of spectra with the change of the 3d electron number from group theoretical consideration.

Electrophysiologic analysis of antidepressant drug effects on the GABA(A) receptor complex based upon antagonist-induced encephalographic power spectrum changes

To better understand antidepressant drug effects on the GABA(A) receptor complex (the GABA(A) receptor, chloride ionophore and benzodiazepine receptor), we investigated how antidepressants influenced power spectrum changes induced by pentylenetetrazol (PTZ), a chloride ionophore antagonist, in the rat hippocampal electroencephalogram (EEG). In control recording, PTZ (27.5 mg/kg i. p.) increased EEG power at frequencies under 12 Hz up to five times. After rats were pretreated with imipramine, fluoxetine or trazodone for 7 days (10 mg/kg i.p., twice a day), PTZ could not increase EEG power to more than three times the power before injection; this effect was not observed after pretreatment for 3 days. These three antidepressants inhibit serotonin uptake, while two other antidepressants, desipramine and nortriptyline, that inhibit norepinephrine uptake failed to counter the PTZ effect. We concluded that antidepressants with serotonergic effects enhanced the function of the GABA(A) receptor complex.

Usefulness of home blood pressure measurements in assessing the effect of treatment in a single-blind placebo-controlled open trial

OBJECTIVES

Reproducibility of home blood pressure measurements (HBP), and the placebo effect on HBP, were examined to establish the number of subjects required in order to observe a significant antihypertensive effect of a drug for a comparative study between placebo and active treatment.

METHODS

Reproducibility of HBP (n = 172 for systolic blood pressure and n = 137 for diastolic blood pressure) and the placebo effect on HBP (n = 35 for systolic and n = 42 for diastolic blood pressure) were examined using a semi-automatic electronic device on untreated hypertensive subjects during 21 consecutive days of measurements. From these two studies, the number of subjects required in order to observe a significant antihypertensive drug effect was assessed. In both studies, measurements from the first 3 days were excluded from the analysis.

RESULTS

Reproducibility, defined as the difference between the initial 5 day average (days 4-8) and the last 5 day average (days 17-21) was -1.9 +/- 7.0/-1.4 +/- 4.8 mmHg (mean +/- SD), indicating high reproducibility with a minimal regression to the mean effect. A placebo was administered after the 8 day run-in period. The difference between the initial 5 day average (days 4-8) and the last 5 day average (days 17-21) was compared. The mean difference was 1.1 +/- 6.2/0.2 +/- 5.7 mmHg, suggesting that there was a minimal, if any, placebo effect. As determined by the power calculations, based on the standard deviations of the tests for reproducibility and the placebo effect, nine of 13 subjects are required to show that a 9/5 mmHg decrease in systolic HBP/diastolic HBP (50% of estimated effective decrease in systolic HBP/diastolic HBP according to the guidelines for clinical trials in Japan) is statistically significant

CONCLUSIONS

The results suggest that the HBP measurement is highly reproducible and that there is a minimal, if any, placebo effect. These characteristics of HBP contribute to minimizing the number of subjects necessary for assessment of antihypertensive drug effects in comparative studies between an active treatment and placebo.

Risk factors and predictors of coronary arterial lesions in Japanese hypertensive patients

The morbidity rate of coronary artery disease has recently increased in Japan. This is attributable to changes from traditional to more westernized lifestyles. In this study, we therefore examined the risk factors and predictors of coronary arterial lesions in Japanese patients with essential hypertension. Coronary angiography was performed in 109 consecutive essential hypertension patients (57 men and 52 women; 66 +/- 8.0 years of age) with either angina pectoris or atypical chest pain, who were chosen from 485 consecutive hypertensive patients in a hypertension clinic in Sendai, Japan. Coronary arterial stenosis of greater than 50% was defined as significant and used as a dependent variable for the multiple regression analysis. Risk factors were defined as factors confirmed to have a causal relationship with coronary arterial lesions, whereas arteriosclerotic complications and hypertensive target organ damage were defined as predictors. Multiple logistic regression analysis was performed using these parameters as independent variables. Of 109 patients, 25 had a coronary arterial stenosis greater than 50%. A smoking habit (odds ratio (OR): 4.48; 95% confidence interval (CI): 1.13-17.82; p<0.05), hypercholesterolemia (OR: 5.34; 95% CI: 1.52-18.73; p<0.05), and 24-h diastolic blood pressure (OR: 2.33; 95% CI: 1.06-5.16; p<0.05) were significant risk factors, whereas carotid intima-media thickness (OR: 5.85; 95% CI: 1.48-23.2; p<0.05) was a significant predictor of coronary arterial lesion. When two of the major risk factors (a smoking habit, hypercholesterolemia, or impaired glucose tolerance including diabetes mellitus) were clustered in addition to the hypertension, the risk of coronary arterial lesions increased by 6.7 to 10.1 times. These findings indicate that the major risk factors established in Caucasians, i.e., a smoking habit, hypercholesterolemia and blood pressure level, are also risk factors for coronary arterial lesions in Japanese with essential hypertension. The presence of two or more risk factors increases the risk of coronary arterial lesions synergistically in the presence of hypertension.

Factors affecting the difference between screening and home blood pressure measurements: the Ohasama Study

OBJECTIVE

To establish the factors affecting the difference between screening and home blood pressure measurements.

DESIGN

A cross-sectional study.

SETTING

General population in a rural Japanese community, Ohasama, Japan.

PARTICIPANTS

There were 1,789 community-based subjects aged > or =40 years, for whom blood pressure was measured at screening site (screening blood pressure) and at home (home blood pressure).

RESULTS

Multiple stepwise regression analysis of all subjects demonstrated that screening pulse pressure was positively associated with the difference between screening and home blood pressure measurements for systolic blood pressure. Age, the use of antihypertensive medication, and smoking status were negatively associated with the difference between measurements of both systolic and diastolic blood pressure.

CONCLUSION

We have demonstrated that age, smoking, antihypertensive medication, and screening pulse pressure are independent predictors of the magnitude of the difference between screening and home blood pressure measurements, suggesting that the necessity to consider these factors, for the detection of the subjects who may be inappropriately treated or misjudged following screening blood pressure measurements.

Biochemical and immunohistological changes in the brain of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse

We investigated neurochemically and neuropathologically the utility of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice as a model of Parkinson's disease. The changes in dopamine D1 and D2 receptors and dopamine uptake sites were determined by quantitative autoradiography using [3H]SCH23390, [3H]raclopride and [3H]mazindol, respectively. Dopamine and 3,4-dihydroxyphenyl acetic acid (DOPAC) contents in the striatum were measured by high-performance liquid chromatography. The distribution of nigral neurons and reactive astrocytes was determined by immunohistochemical staining with antibody against tyrosine hydroxylase (TH) and glial fibrillary acidic protein (GFAP). The mice received four intraperitoneal injections of MPTP (10 mg/kg) at 1-h intervals and then the brains were analyzed at 3 and 7 days after the treatments. No significant change in dopamine D1 receptors was observed in the striatum and substantia nigra after acute treatment with MPTP. Dopamine D2 receptors were reduced significantly in the substantia nigra only 7 days after the MPTP treatment, whereas striatum showed no significant change in the binding throughout the experiments. In contrast, dopamine uptake sites were reduced markedly in the striatum and substantia nigra 3 and 7 days after the MPTP treatment. Dopamine and DOPAC content were also reduced in the striatum 3 and 7 days after the MPTP treatment. An immunohistochemical study indicated a loss of the number of TH-positive neurons in the substantia nigra 7 days after the MPTP treatment. In contrast, numerous GFAP-positive astrocytes were evident in the striatum 7 days after the MPTP treatment. These results provide valuable information for the pathogenesis of acute stage of Parkinson's disease.

Retinoic acids and thyroid hormone act synergistically with dexamethasone to increase growth hormone-releasing hormone receptor messenger ribonucleic acid expression

The effects of all-trans-retinoic acid (RA), 9-cis-retinoic acid (9cRA), and thyroid hormone (T3) on GH-releasing hormone receptor (GHRH-R) messenger RNA (mRNA) expression were studied using ribonuclease protection assay in the fetal rat pituitary gland and in MtT/S cells, a clonal GH cell line derived from an estrogen-induced somatotropic tumor in the rat. Although RA (1 microM), 9cRA (1 microM), or T3 (1 nM) alone showed little effect on GHRH-R mRNA expression in the MtT/S cells, each of these substances was found to act synergistically with dexamethasone (DEX; 500 nM) to increase GHRH-R mRNA expression. The effects of RAs and T3 were dose dependent, with maximum effects observed at 1 microM and 1 nM, respectively. The maximum effect of RAs or T3 was not further augmented by the addition of T3 or RAs, respectively. No apparent differences were observed in this study between the actions of RA and 9cRA. The Northern analyses showed that MtT/S cells express retinoic acid receptor alpha2 mRNA and thyroid hormone receptor beta2 mRNA, and DEX did not affect the levels of these mRNAs. This suggests that the role of DEX in enabling RAs or T3 to up-regulate GHRH-R mRNA levels is not an induction of the expression of each specific receptor for RAs and T3. The similar enhancement of DEX induction of GHRH-R mRNA by RAs or T3 was also observed in the fetal rat pituitary gland in culture, suggesting that RA and/or T3 is involved in the mechanisms responsible for the developmentally regulated expression of GHRH-R mRNA.

Effect of ifenprodil on ocular tissue circulation in rabbits

Ifenprodil tartrate has long been employed as a cerebral vasodilator with alpha and N-methyl-D-aspartate (NMDA) receptor antagonistic activities. The purpose of this study was to evaluate the effects of ifenprodil on ocular circulation in rabbits. Experiments were performed during the dark phase in Dutch rabbits conditioned to a schedule of alternating 12-hr periods of light and dark. Effects on ocular tissue blood velocity were estimated using the laser speckle method in the iris, posterior choroid, and optic nerve head (ONH). Measurements of tissue blood velocity were performed both after intravenous injection of ifenprodil at a dose of 0.2 mg/kg, 0.1 mg/kg, and the same volume of the vehicle, and after topical instillation of 0.5% ifenprodil (50 microl) twice daily for 1, 3 and 20 days unilaterally in a masked manner. Intraocular pressure (IOP) was also measured during the experimental period. Intravenous administration of ifenprodil caused a significant increase in blood velocity in the ONH, choroid, and iris, but ONH circulation was affected at a lower dose than uveal circulation. In the topical instillation experiment, IOP in the ifenprodil-treated eye was significantly lower, by approximately 2 mmHg, than that in the contralateral eye when the laser speckle measurement was performed. Twice-daily, unilateral 0.5% ifenprodil instillation significantly increased blood velocity in the iris after 3 days and that in the ONH and posterior choroid after 20 days in the treated eye. Topical 0.5% ifenprodil increased blood velocity in the iris, posterior choroid, and ONH after multiple dosings. After systemic administration, ONH circulation appeared to be influenced at a lower dose than was uveal circulation.

Prognosis of isolated systolic and isolated diastolic hypertension as assessed by self-measurement of blood pressure at home: the Ohasama study

BACKGROUND

Although the clinical significance of systolic-diastolic hypertension and isolated systolic hypertension has been established, the significance of isolated diastolic hypertension has not been fully investigated.

OBJECTIVE

To clarify the prognostic significance of isolated systolic and isolated diastolic hypertension as assessed by self-measurement of blood pressure (BP) at home (home BP measurements), which has a better reproducibility and prognostic value than casual BP measurements in the general population.

SUBJECTS AND METHODS

We obtained home BP measurements for 1913 subjects aged 40 years or older, then followed up their survival status (mean, 8.6 years). We classified the subjects into the following 4 groups according to their home BP levels: systolic-diastolic hypertension, isolated systolic hypertension, isolated diastolic hypertension, and normotension. The prognostic significance of each type of hypertension for the risk of cardiovascular mortality risk was investigated using a Cox proportional hazards regression model adjusted for possible confounding factors.

RESULTS

The risk for isolated systolic hypertension and systolic-diastolic hypertension were significantly higher than the relative hazard for normotension, while isolated diastolic hypertension was associated with no significant increase in risk. Home pulse pressure measurement was also independently associated with an increase in the risk of cardiovascular mortality.

CONCLUSIONS

Isolated diastolic hypertension, as assessed by home BP measurements, carried a low risk of cardiovascular mortality, similar to that found in subjects with normotension, suggesting that the prognosis of hypertension would be improved by treatment focused on systolic rather than on diastolic home BP measurements. To our knowledge, this study is the first to demonstrate the clinical significance of pulse pressure as assessed by home BP measurement. Arch Intern Med. 2000;160:3301-3306.

Prognostic significance of blood pressure and heart rate variabilities: the Ohasama study

To investigate the association between cardiovascular mortality and short-term variabilities in blood pressure and heart rate, we performed a long-term prospective study of ambulatory blood pressure monitoring in Ohasama, Japan, starting in 1987. We obtained ambulatory blood pressure and heart rate in 1542 subjects >/=40 years of age. Blood pressure and heart rate variabilities were estimated as a standard deviation measured every 30 minutes by ambulatory monitoring. There were 67 cardiovascular deaths during the follow-up period (mean=8.5 years). The Cox proportional hazards model, adjusted for possible confounding factors, demonstrated a significant increase in cardiovascular mortality, with an increase in daytime systolic ambulatory blood pressure variability. A similar trend was observed in daytime diastolic and nighttime ambulatory blood pressures. Cardiovascular mortality rate increased linearly, with a decrease in daytime heart rate variability. Subjects in whom the daytime systolic ambulatory blood pressure variability was larger than third quintile and the daytime heart rate variability was lower than the mean-SD were at extremely high risk of cardiovascular mortality. The blood pressure and heart rate variabilities obtained every 30 minutes by ambulatory blood pressure monitoring were independent predictors for cardiovascular mortality in the general population.

Genetic determination of human essential hypertension

Recent advances in genetic determination of human essential hypertension (EHT) are discussed by reviewing the candidate genes. Candidate genes have been selected based on genetic information from classical linkage analysis (affected sib-pair analysis) or mendelian hypertension (autosomal dominant inheritance of hypertension). Most of these genes are, directly or indirectly, coupled to salt handling of the kidney, being included in the renin-angiotensin system (RAS), steroid-hormone metabolism, and renal sodium transporters. Angiotensinogen (AGT) gene in RAS was first described as a strong candidate associated with the onset of hypertension, since sib-pair linkage analysis has demonstrated the trait loci for hypertension which includes the coding region for AGT. M235T polymorphism of AGT has been studied extensively in many populations including Japanese, and the results suggest a weak, but significant linkage with hypertension. The presence (insertion [I]) or absence (deletion [D]) of 287bp in intron 16 of angiotensin converting enzyme gene has also been examined in RAS, and the results suggest D polymorphism as a risk factor for hypertension in men. Other components in RAS, such as renin, angiotensinogen II type I receptor, or kallikrein have also been studied, but the available information is still incomplete. Genetic investigations of mendelian hypertension has identified the genetic mechanisms for glucocorticoid remediable aldosteronism, apparent mineral corticoid excess, and Liddle's syndrome as chimeric gene duplications of CYP11B1 (aldosterone synthase gene) and CYP11B2 (11beta-hydroxylase gene), mutations in the gene of 11beta-hydroxysteroid dehydrogenase type 2 that catalyzes the conversion of cortisol to cortisone, and mutations in beta or gamma subunit of epithelial sodium channel (ENaC), respectively. Subsequently, genetic variants of CYP11B2 and beta or gamma subunit of ENaC have been found, suggesting the -344C polymorphism of CYP11B2, 594S variant of betaENaC, and two rare variants of gammaENaC as risk factors for EHT. In spite of the extensive research, haplotypes in individual populations remain to be elucidcated in most candidate genes. Even casual conclusions of possible linkage with EHT need to be further examined with better determinations of phenotypes, such as ambulatory and home blood pressure monitoring or identification of onset of hypertension in cohort studies.

Antibacterial carbohydrate monoesters suppressing cell growth of Streptococcus mutans in the presence of sucrose

The growth-inhibitory effect of 23 carbohydrate monoesters synthesized by lipases and proteases were assayed to obtain antibacterial agents that suppress the cell growth of Streptococcus mutans. Among the carbohydrate esters synthesized, galactose and fructose laurates showed the highest growth-inhibitory effect, while the other analogs of hexose laurates showed no antibacterial activity, indicating that configuration of the hydroxyl group in carbohydrate moiety markedly affects the antibacterial activity. The cell growth of S. mutans was suppressed by fructose laurates even in the presence of sucrose. Thus, enzymatic synthesis of carbohydrate esters with different core structures has great potential for developing antibacterial agents applicable to food additives.

Protective effect of riluzole on MPTP-induced depletion of dopamine and its metabolite content in mice

The neuroprotective effects of riluzole (2-amino-6-trifluoromethoxy benzothiazole), a Na+ channel blocker with antiglutamatergic activity, MK-801, a blocker of N-methyl-D-aspartate (NMDA) receptors and monoamine oxidase (MAO) inhibitor pargyline were compared in the model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced depletion of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) levels in mice. The mice received four intraperitoneal injections of MPTP (10 mg/kg) at 1-hr intervals and then the brains were analyzed at 1, 3 and 7 days after the treatments. Dopamine and DOPAC levels were significantly decreased in the striatum from 1 day after MPTP treatments. A severe depletion in dopamine and DOPAC levels was found in the striatum 3 and 7 days after MPTP treatments. Riluzole dose-dependently antagonized the MPTP-induced decrease in dopamine and DOPAC levels in the striatum. Pargyline also protected against MPTP-induced decrease in dopamine levels in the striatum. However, this drug showed no significant change in the striatal DOPAC levels. On the other hand, MK-801 failed to protect against MPTP-induced decrease in dopamine levels in the striatum. However, MK-801 reversed the MPTP-induced decrease in DOPAC levels. These results suggest that riluzole can protect against MPTP-induced striatal dopamine and DOPAC depletion in mice. This protective effect may be caused by inactivation of voltage-dependent Na+ channels by riluzole. Furthermore, the present study suggests that the activation of NMDA receptors does not mainly contribute to MPTP-induced neurodegeneration, whereas MAO, especially MAO type B(MAO-B) plays a crucial role in MPTP-induced degeneration of the nigrostriatal dopaminergic neuronal pathway.