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Biomedical subjects

T Kondo

Publications and source records attributed to T Kondo.

At least 235 records · Page 13Linked to original sources
PubMed2000

Molecular mechanisms of the initiation of oocyte maturation: general and species-specific aspects.

Stimulated by maturation-inducing hormone secreted from follicle cells surrounding the oocytes, fully-grown oocytes mature and become fertilisable. During maturation, immature oocytes resume meiosis arrested at the first prophase and proceed to the first or second metaphase at which they are naturally inseminated. Paying special attention to general and species-specific aspects, we summarise the mechanisms regulating the initial phase of oocyte maturation, from the reception of hormonal signals on the oocyte surface to activation of the maturation-promoting factor in the cytoplasm, in amphibians, fishes, mammals and marine invertebrates.

Amphibians↗
PubMed2000

Relation between myocardial response to dobutamine stress and sympathetic nerve activation in patients with idiopathic dilated cardiomyopathy: a comparison of 123I-MIBG scintigraphic and echocardiographic data.

It is likely that a close association exists between findings obtained by two methods: dobutamine stress echocardiography and 123I-MIBG scintigraphy. Both of these methods are associated with beta-adrenergic receptor mechanisms. This study was conducted to demonstrate the relation between myocardial response to dobutamine stress and sympathetic nerve release of norepinephrine in the failing heart. In 12 patients with heart failure due to idiopathic dilated cardiomyopathy, the myocardial effects of dobutamine stress were evaluated by low-dose dobutamine stress echocardiography: and sympathetic nerve function was evaluated by scintigraphic imaging with iodine-123 [123I] meta-iodobenzylguanidine (MIBG), an analogue of norepinephrine. Echocardiography provided quantitative assessment of wall motion and left ventricular dilation; radiotracer studies with 123I-MIBG provided quantitative assessment of the heart-to-mediastinum (H/M) uptake ratio and washout rate. Results showed that H/M correlated with baseline wall motion (r = 0.682, p = 0.0146), wall motion after dobutamine stress (r = 0.758, p = 0.0043), the change in wall motion (r = 0.667, p = 0.0178), and with left ventricular diastolic diameter (r = 0.837, p = 0.0007). In addition, the 123I-MIBG washout rate correlated with baseline wall motion (r = 0.608, p = 0.0360), wall motion after dobutamine stress (r = 0.703, p = 0.0107), and with the change in wall motion (r = 0.664, p = 0.0185). Wall motion, especially in the myocardial response to dobutamine stress, is related to sympathetic nerve activity in heart failure.

3-Iodobenzylguanidine↗
PubMed2000

Effects of repeated ingestion of grapefruit juice on the single and multiple oral-dose pharmacokinetics and pharmacodynamics of alprazolam.

The effects of repeated ingestion of grapefruit juice, an inhibitor of cytochrome P450 3A4 (CYP3A4), on the pharmacokinetics and pharmacodynamics of both single and multiple oral doses of alprazolam, a substrate of CYP3A4, were examined. In study 1, eight healthy volunteers ingesting 600 ml/day water or grapefruit juice for 10 days took a single oral 0.8-mg dose of alprazolam on the eighth day. Plasma drug concentrations were monitored up to 48 h after alprazolam dosing together with evaluation of psychomotor function. Grapefruit juice altered neither the plasma concentrations of alprazolam at any time points, any pharmacokinetic parameters, nor the majority of psychomotor function parameters in subjects. In study 2, 11 patients with anxiety disorders receiving alprazolam (0.8-2.4 mg/day) ingested grapefruit juice (600 ml/day) for 7 days. Blood samples were collected before and during grapefruit juice ingestion and 1 week after its discontinuation together with an assessment of clinical status. Grapefruit juice altered neither the steady-state plasma concentration of alprazolam nor the clinical status in patients. The present study shows that grapefruit juice is unlikely to affect pharmacokinetics or pharmacodynamics of alprazolam due to its high bioavailability.

Adult↗
PubMed2000

Prolactin response to nemonapride, a selective antagonist for D2 like dopamine receptors, in schizophrenic patients in relation to Taq1A polymorphism of DRD2 gene.

The dopamine D2 receptor (DRD2) gene has a Taq1A restriction fragment length polymorphism yielding two alleles, A1 and A2. It has been shown that the subjects with less frequent allele, the A1 allele, have lower density and diminished function of DRD2 in the striatum, compared to those with no A1 allele. In the present study, the relationship between this polymorphism and prolactin response to nemonapride, an antipsychotic drug with selective and potent DRD2 antagonistic property, was investigated in 25 Japanese schizophrenic inpatients (13 males, 12 females). The daily dose of nemonapride was fixed at 18 mg, and the duration of treatment was 3 weeks. Taq1A genotypes were determined by the polymerase chain reaction method. Plasma prolactin concentrations were measured by enzyme immunoassay. The subjects were divided into four subgroups by gender and Taq1A genotypes, i.e., six males and eight females with the A1 allele, seven males and four females with no A1 allele. The (delta)prolactin (change from the pretreatment concentration) at 1 week was significantly (P<0.05) higher in females with the A1 allele (78.0 +/- 47.1 ng/ml) than in males with the A1 allele (33.4 +/- 14.0 ng/ml) or with no A1 allele (29.5+/-24.8 ng/ml). In addition, (delta)prolactin at 3 weeks was significantly (P<0.05) higher in females with the A1 allele (98.1+/-67.9 ng/ml) than in females with no A1 allele (33.4+/-24.6 ng/ml), males with the A1 allele (29.1+/-17.3 ng/ml) or males with no A1 allele (28.6+/-22.0 ng/ml). The present study thus suggests that female patients with the A1 allele show a greater prolactin response to nemonapride, who may have a high risk for adverse effects associated with neuroleptic-induced hyperprolactinemia.

Adolescent↗
PubMed2000

Effect of vibration magnitude and repetitive exposure on finger blood flow in healthy subjects.

In order to study the effect of the magnitude of vibrations and repetitive exposure on finger blood flow, we exposed ten healthy subjects to three experimental conditions: (1) vibration of 3.16 m/s2 at 60 Hz, (2) vibration of 31.6 m/s2 at 60 Hz, and (3) no vibration, as a control. Under the experimental conditions, the right hand was exposed to 5-min vibration three times, with intervening 5-min rests. Meanwhile, the blood flows of both middle fingers were continuously measured with a blood flow meter based on the thermal diffusion method. Finger blood flow was significantly decreased in both hands with exposure to vibrations of 3.16 m/s2 and 31.6 m/s2. Increased magnitude of vibration tended to enhance the decrease in finger blood flow in both hands, and repeated exposure to vibration had cumulative effects on the decrease in finger blood flow in the unexposed left hand.

Adult↗
PubMed2000

Cold pain prolongs gastric emptying of liquid but not solid meal: an electrical impedance tomography (EIT) study.

Stressful stimuli are reported to affect gastric emptying. However, methods for measuring gastric emptying are, in themselves, stressful. Electrical impedance tomography (EIT) is a method for measuring gastric emptying noninvasively. We used EIT to measure gastric emptying of liquid and solid meals to determine the effect of cold pain stress on gastric emptying. EIT (DAS-01P APT system; University of Sheffield, UK) was carried out in six healthy women (age, 21.6 +/- 0.4 [mean +/- SD] years) who had ingested a liquid (potage, 263 g; 139 kcal) or solid (beef patty, 205 g; 435 kcal) test meal. Cold pain stimuli consisted of repeated immersions of the subject's non-dominant hand into ice water (4 degrees C) for 1 min, with a 15-s recovery period between immersions, for a total of 20 min. For the control stimulus, water at 37 degrees C was used. The cold pain stimulus was applied immediately after the ingestion of a test meal. All studies were carried out randomly in each subject at intervals of more than 1 week. With cold pain, the half emptying time of the liquid meal was significantly greater than that with the control stimulus (47.6 +/- 26.1 min vs 28.1 +/- 10.8 min, P < 0.05). For the solid meal, the half emptying time did not differ between stimuli (101.9 +/- 44.8 min with cold pain vs 92.6 +/- 30.5 min with control stimulus). There were no significant differences in lag time between the liquid and solid meals. Cold pain stress delayed gastric emptying of liquid but not solid meals.

Adult↗
PubMed2000

Caspase activities and tumor necrosis factor receptor R1 (p55) level are elevated in the substantia nigra from parkinsonian brain.

The activities of caspase-1 and caspase-3 were measured by use of fluoropeptides as substrates for the first time in the brain (substantia nigra, caudate nucleus, putamen, cerebellum, and frontal cortex) from control and parkinsonian patients. The activities of caspases in the brain were significantly higher in the substantia nigra from parkinsonian patients than those in the brain from control patients (p < 0.01). However, the activities of caspases in the caudate nucleus, putamen, cerebellum, and frontal cortex showed no significant difference between parkinsonian and control patients. The tumor necrosis factor (TNF) receptor R1 (TNF-R1, p55) level was also elevated in the substantia nigra of the parkinsonian brain in comparison with that of controls (p < 0.05). Since both caspases and TNF-R1 may play important roles in apoptotic cell death through TNF-alpha-induced signaling pathway, our present data suggest the presence of a proapoptotic environment in the substantia nigra of parkinsonian brain, probably inducing vulnerability of neurons and glias towards a variety of noxious factors.

Adult↗
PubMed2000

Is endogenous isoprene the only coeluting compound in the measurement of breath pentane?

Pentane is a widely used index of lipid peroxidation. Although isopentane, an isomer of pentane, is a major component of ambient air in urban areas, many studies have disregarded the possibility that this compound is coeluted in the measurement of breath pentane. In the present study, a gas chromatograph equipped with a cold trap apparatus and a large-bore glass capillary column was used for determination of pentane, isopentane and isoprene in breath and ambient air. Isoprene was detected in all subjects at a concentration higher than that in the ambient air. However, the concentrations of breath pentane and isopentane were similar to, or less than, those of the ambient air. We suggest that great care is required in the measurement of breath pentane so that endogenous isoprene and ambient isopentane are not coeluted.

Adult↗
PubMed2000

Plasma concentration of brain natriuretic peptide as a biochemical marker for the evaluation of right ventricular overload and mortality in chronic respiratory disease.

The purpose of this study was to evaluate whether the plasma brain natriuretic peptide (BNP) concentration is a useful marker of right ventricular (RV) overload and whether it has prognostic value as a predictor of death in patients with chronic respiratory disease (CRD). We measured the plasma BNP and atrial natriuretic peptide (ANP) concentrations in 31 consecutive patients with CRD who underwent right-heart catheterization to evaluate pulmonary hypertension. All patients were followed for >12 months. The plasma BNP concentration closely correlated with the mean pulmonary artery pressure and pulmonary vascular resistance (r=0.62, P<0.0005 and r=0. 85, P<0.0001), and showed a weak linear correlation with cardiac output (r=-0.36, P<0.05). During the follow-up period, 5 (16%) end-stage CRD deaths (4 RV heart failure and 1 respiratory infection) and 2 non-end-stage CRD deaths occurred. In a stepwise multivariate Cox proportional-hazards regression analysis including age, sex, BNP, ANP, hemodynamic variables and the ratio of PaO(2) to fraction of inspired oxygen, only BNP (P<0.05) was an independent predictor of end-stage CRD death. The upward and leftward shift in the receiver operating characteristic curve between patients with end-stage CRD death and those without was greater for BNP than for ANP. Our findings suggest that the plasma BNP concentration may be an inexpensive, simple and useful marker of RV overload and end-stage CRD death in CRD patients. These preliminary results need to be confirmed in a large series of CRD patients.

Aged↗
PubMed2000

Contribution of each caffeoyl residue of the pigment molecule of gentiodelphin to blue color development.

To clarify the function of each caffeoyl residue in the diacylated anthocyanin gentiodelphin, a pigment from the blue flower of Gentiana makinoi, two mono-deacyl derivatives were compared for both color development and stability. In neutral solution, 3,5-di-O-beta-D-glucopyranosyl-3'-O-(6-O-caffeoyl-beta-D- glucopyranosyl)delphinidin was both bluer and more stable than 3,3'-di-O-beta-D-glucopyranosyl-5-O-(6-O-caffeoyl-beta-D- glucopyranosyl)delphinidin. Conformational analysis of each derivative under acidic conditions revealed only the 3'-O-caffeoylglucopyranosyl derivative to demonstrate intramolecular stacking. Additionally, the acyl residue in the B-ring contributed more to blue color development than that in the A-ring.

Acylation↗
PubMed2000

Ventilatory responses to hypercapnia and hypoxia following chronic hypercapnia in the rat.

This study investigated the effects of an 18 week exposure to 10% CO(2) in air on minute ventilation (V(E)), breathing pattern and the chemoresponiveness of rats to hypoxic and hyperoxic stimuli. We found that V(E) remained elevated over the 18 weeks. Nonetheless, the breathing pattern changed significantly. Tidal volume increased and the durations of inspiration and the total cycle decreased. After the sustained hypercapnia the mean Pa(CO(2)) was 72.0+/-5.1 (S. D.) mmHg. Every 6 weeks the chemoresponiveness of the CO(2)-exposed rats was tested by an acute exposure sequentially to room air, then a 6% O(2), 10% CO(2) and 84% N(2) gas mixture, and finally a 90% O(2) in 10% CO(2) mixture. On either room air or the hyperoxic-hypercapnic mixture V(E) fell to its pre-hypercapnic level. On the hypoxic-hypercapnic mixture V(E) increased significantly. These results demonstrate that the initial stimulating effect of 10% CO(2) on V(E) persisted for the entire 18 weeks without altering hypoxic or hyperoxic ventilatory responses.

Animals↗
PubMed2000

Association between Taq1 a dopamine D2 receptor polymorphism and psychopathology of schizophrenia in Japanese patients.

1. Previous reports showed that the A1 allele of Taq1 A dopamine D2 receptor polymorphism was associated with lowered density and diminished function of dopamine D2 receptor. In this study, association between Taq1 A dopamine D2 receptor polymorphism and psychopathology of schizophrenia was investigated. 2. The subjects were 61 acutely exacerbated schizophrenic patients who were all Japanese descent and had received no medication for at least one month before this study. Pretreatment psychotic symptoms were assessed by the Brief Psychiatric Rating Scale (BPRS). The Taq1 A genotypes, the A1 and A2 alleles, were determined by polymerase chain reaction method. 3. The patients were divided into three genotype groups; i.e., the patients with A1/A1 allele (n=6), those with A1/A2 allele (n=32) and those with A2/A2 allele (n=23). 4. There was no significant difference in total BPRS, subgrouped symptoms (positive, negative, anxiety-depression, excitement and cognitive symptoms) or any scores of BPRS items among the three Taq1 A genotype groups. 5. The present study suggests that Taq1 A dopamine D2 receptor polymorphism does not play an important role in psychopathological symptoms of schizophrenia.

Adult↗
PubMed2000

Distribution, metabolism and excretion of butylidenephthalide of Ligustici chuanxiong rhizoma in hairless mouse after dermal application.

The absorption, distribution and excretion of butylidenephthalide after dermal application to hairless mouse have been examined with [8-14C]butylidenephthalide. By the investigation of the whole body autoradiogram and liquid scintillation analysis, it was indicated that the transdermally applied butylidenephthalide quickly permeate into peripheral circulation system without accumulation in the skin and then distribute into lung, liver, bile and kidney. The total radioactivity, however, was decreased due to excretion into urine, and in the case of i.v.-administration, 80% of the administered butylidenephthalide was excreted into urine within 24 h, while only 5% was excreted into feces within 24 h. Then, the metabolite in urine was determined to be a cysteine conjugate by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method. Thus, it has been concluded that after dermal application butylidenephthalide quickly permeates through skin into peripheral circulation system; distributes to lung, liver, bile and kidney; and then excreted into urine as a cysteine adduct.

Administration, Cutaneous↗
PubMed2000

Assessment of vascular aging and atherosclerosis in hypertensive subjects: second derivative of photoplethysmogram versus pulse wave velocity.

The pulse wave velocity (PWV) and the photoplethysmogram (PTG) are noninvasive methods for evaluating the pulse wave. The PWV has been associated with age and arterial hypertension, and an index of the second derivative of PTG (SDPTG) is correlated with age and other risk factors for atherosclerosis. The aim of this study was to compare SDPTG and PWV concerning the influencing factors of vascular compliance, including age and atherosclerosis, in a large hypertensive population. We studied consecutively 524 essential hypertensives, 140 with atherosclerotic alterations (AA), defined on the basis of clinical events including coronary heart disease, peripheral vascular disease, stroke, and abdominal aorta aneurysm. The PWV carotid-femoral was measured by a Complior device and the SDPTG was recorded by Fukuda FCP-3166. The augmentation index (AUI) of PTG was defined as the ratio of the late systolic peak to that of the early systolic peak in the pulse. The SDPTG consists of an a,b,c, and d wave in systole and an e wave in diastole; an SDPTG aging index (AI) was calculated as (b-c-d-e)/a. The patients with AA presented a higher PWV (14.9 +/- 4 m/sec v 12.4 +/- 2 m/sec, P < .001), PTG AUI (0.322 +/- 0.16 v 0.252 +/-0.09, P < .001), and SDPTG AI (-0.093 +/- 0.03 v -0.271 +/- 0.018, P < .001). However, in patients 60 years of age, only PWV remained higher in those with AA, whereas in patients >60 yr, both PWV and SDPTG AI remained higher in those with AA. The PWV was independently influenced by age, systolic blood pressure, glucose, AA, and plasma creatinine, whereas the PTG AUI was influenced by age and systolic pressure and the SDPTG AI by age and AA. In a logistic regression model for the presence of AA, including age, plasma creatinine, smoking, and diastolic BP, PWV was a significant independent determinant of AA, whereas SDPTG-AI weakly entered into the model. This study provides evidence that the aortic PWV reflects better than the SDPTG the modifications of the arterial compliance related to age, blood pressure, and atherosclerosis. However, the SDPTG AI may be useful for evaluation of vascular aging in hypertensives.

Aged↗