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T Nakata

Publications and source records attributed to T Nakata.

At least 91 records · Page 5Linked to original sources
PubMed1999

Morphological evidence of the inhibitory effect of taxol on the fast axonal transport.

The short term effects of taxol, a stabilizing drug of microtubules, on the peripheral nerves in the rat was investigated using a new chamber system which can be applied to incubate a sciatic nerve with various solutions in vivo. A functional analysis of retrograde axonal transport using rhodamine-labeled wheat germ agglutinin (WGA-rhodamine) showed the inhibitory effect of the drug. An electron microscopic study also revealed that a variety of vesicles were observed to accumulate on both the proximal and the distal sides of the chamber, however, no significant increase in the number of microtubules in the axons, based on the pharmacological effect of the drug, was observed even though one had been expected. These findings support the inhibitory effect of taxol on the fast axonal transport of the neurons. Furthermore, the accumulated vesicles were morphologically different from those accumulated by ligation. These results suggest that a special component of the fast axonal transport was thus selectively blocked by the drug.

Animals↗
PubMed1999

Cardiac BMIPP imaging in acute myocardial infarction.

Fatty acid metabolism functions as a major energy-producing system under aerobic conditions, but it is impaired immediately after myocardial ischaemia. This imaging can provide intracellular information which cannot be obtained by angiographical, perfusional or functional analysis. 123I-BMIPP and perfusion imagings in patients with acute myocardial infarction have demonstrated three different correlations between myocardial perfusion and fatty acid metabolism: concordant defects of perfusion and BMIPP which represent scar or non-viable tissue; lower BMIPP uptake relative to perfusion (perfusion-BMIPP mismatch) which implicates metabolically damaged, often dysynergic, but viable myocardium; and equivalently normal uptakes of perfusion and BMIPP in completely salvaged myocardium. Identification of these perfusion-metabolism correlations contributes to the detection of ischaemia-related myocardial injury in viable and non-viable myocardium, to the prediction of post-ischaemic or post-interventional functional recovery and to the identification of patients who have myocardium at ischaemic risk. Further clinical investigations might reveal more clearly the pathophysiological and prognostic implications of cardiac BMIPP imaging in patients with acute myocardial infarction.

Fatty Acids↗
PubMed1999

Schizophrenia: is it time to replace the term?

The attitudes of Japanese psychiatrists toward their patients who suffer from schizophrenia were investigated. We were concerned specifically with whether the psychiatrists inform their patients of the suspected diagnosis. We discuss how the term 'schizophrenia' may influence a psychiatrist's decision to inform his patients of the diagnosis. A self-reported questionnaire was distributed to 150 executive board members of the Japanese Society of Psychiatry and Neurology and analysis of the data obtained from 110 respondents was carried out. The results showed that the concepts that psychiatrists use when they give a diagnosis of schizophrenia vary considerably. Fifty-nine per cent of the respondents informed their patients of a diagnosis of schizophrenia on a case-by-case basis, while 37% informed only the patients' families. A tree analysis showed that the most important predictors for informing the patients of the diagnosis were assumptions about the public image of schizophrenia and a negative impression of the term schizophrenia, translated as 'Seishin Bunretsu Byou' in Japanese. The results revealed that the Japanese term for schizophrenia influences a psychiatrist's decision to inform patients of the diagnosis and that, by changing the term to a less stigmatized one, the disclosure of information about schizophrenia to patients would be promoted.

Attitude of Health Personnel↗
PubMed1999

Sympathetic activation and contribution of genetic factors in hypertension with neurovascular compression of the rostral ventrolateral medulla.

OBJECTIVE: The rostral ventrolateral medulla is an important center for the regulation of sympathetic and cardiovascular activities. Reportedly, neurovascular compression of the rostral ventrolateral medulla may be causally related to essential hypertension. We aimed to determine the mechanism behind elevated blood pressure in hypertensive patients with compression of the rostral ventrolateral medulla and to investigate whether genetic factors contribute to the etiology of hypertension with compression. DESIGN AND METHODS: The study included 56 patients with essential hypertension and 25 normotensive individuals. With the use of magnetic resonance imaging, the essential hypertension group was subdivided into hypertension with compression and without compression groups. We compared plasma levels of hormones that raise blood pressure and family histories of hypertension between the two hypertension groups and the normotension group. RESULTS: Plasma norepinephrine levels, but not plasma renin activity, aldosterone, epinephrine, or vasopressin levels, were significantly higher in the hypertension with compression group (389+/-53 pg/ml) than in the hypertension without compression group (217+/-38, P<0.05) or in the normotension group (225+/-30, P<0.05). The percentage of individuals who had two hypertensive parents was significantly higher in the hypertension with compression group (39.4%) than in the hypertension without compression group (13.0%, P<0.05) or in the normotension group (8.0%, P<0.01). CONCLUSIONS: These results indicate that neurovascular compression of the rostral ventrolateral medulla might be, at least in part, causally related to essential hypertension by increasing sympathetic nerve activity. They also suggest that genetic factors might contribute to the etiology of hypertension with neurovascular compression.

Alleles↗
PubMed1999

Central effects of endothelin and its antagonists on sympathetic and cardiovascular regulation in SHR-SP.

Intracerebroventricular injections of endothelin-1 (ET-1) are reported to cause dose-related increases in sympathetic nerve activity and blood pressure in anesthetized normotensive rats. These studies were performed to determine the following: which endothelin receptor, A or B, is involved in mediating sympathetic and cardiovascular effects of ET-1 injected centrally; whether central endothelin tonically participates in blood pressure regulation in normotensive rats; and whether the altered endothelin system in the central nervous system contributes to blood pressure elevation in hypertensive rats. ET-1, ET-A antagonist (BQ-123), or ET-B antagonist (RES-701-1) was injected into the lateral cerebral ventricle (i.c.v.) of urethane-anesthetized normotensive Wistar and Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHRs), and stroke-prone SHRs (SHR-SPs). In Wistar rats, i.c.v. injections of ET-1 (1, 5, 10 pmol) consistently increased sympathetic nerve activity, thereby elevating blood pressure in a dose-related manner. The pressor responses induced by i.c.v. ET-1 were abolished after intravenous pretreatment with phentolamine. Neither ET-A nor ET-B antagonist, when injected centrally, altered basal levels of sympathetic nerve activity, heart rate, or blood pressure in Wistar rats. However, sympathetic activation and pressor responses induced by i.c.v. injection of endothelin were completely abolished after i.c.v. pretreatment with ET-A antagonist but were unaffected after pretreatment with ET-B antagonist. Although i.c.v. injections of ET-1 increased sympathetic nerve activity and blood pressure in WKY rats, SHRs, and SHR-SPs, the magnitudes of these responses did not differ among these three groups. In contrast, i.c.v. injections of ET-A antagonist decreased sympathetic nerve activity, blood pressure, and heart rate only in SHR-SPs, but not in WKY rats and SHRs. In addition, the depressor effects of i.c.v. ET-A antagonist in SHR-SPs were ascertained while these rats were awake. In summary, i.c.v. injections of ET-1 increased sympathetic nerve activity and blood pressure via ET-A receptors but not via ET-B receptors. Central ET might tonically activate sympathetic nerve activity to thereby contribute to blood pressure elevation in SHR-SPs, but not in WKY rats and SHRs.

Anesthesia↗
PubMed1999

Genetic organization and characteristics of the 3-(3-hydroxyphenyl)propionic acid degradation pathway of Comamonas testosteroni TA441.

Comamonas testosteroni TA441 degrades 3-(3-hydroxyphenyl)propionate (3HPP) via the meta pathway. A gene cluster required for degradation of 3HPP was cloned from strain TA441 and sequenced. The genes encoding six catabolic enzymes, a flavin-type hydroxylase (mhpA), extradiol dioxygenase (mhpB), 2-keto-4-pentenoate hydratase (mhpD), acetaldehyde dehydrogenase (acylating) (mhpF), 4-hydroxy-2-ketovalerate aldolase (mhpE) and the meta cleavage compound hydrolase (mhpC), were found in this cluster, encoded in this order. mhpD and mhpF were separated by two genes, orf4 and orf5, which were not necessary for growth on 3HPP. The gene mhpR, encoding a putative transcriptional activator of the IcIR family, was located adjacent to mhpA in the opposite orientation. Disruption of the mhpB or mhpR genes affected growth on 3HPP or trans-3-hydroxycinnamate. The mhpB and mhpC gene products showed high specificity for 3-(2,3-dihydroxyphenyl)propionate (DHPP) and the meta cleavage compound produced from DHPP, respectively.

Aldehyde Oxidoreductases↗
PubMed1999

Clinical experience of long-term transdermal treatment with nitric oxide donor for women with preeclampsia.

Isosorbide dinitrate (ISDN), a nitric oxide donor, was applied transdermally for 4-16 days to 4 preeclamptic women with oligohydramnios, intrauterine fetal growth retardation (IUGR), and elevated resistance of blood flow in the uterine arteries. Pulsed Doppler ultrasonography revealed immediate and drastic improvement of pulsatility index (PI) of uterine arteries following treatment with ISDN. The average PI in uterine arteries of the 4 patients was reduced to approximately 67% of that of the untreated state. In 2 patients the amniotic fluid gradually increased over a few days which suggested improvement of fetoplacental circulation during administration of ISDN. This study suggests that long-term transdermal ISDN is an effective therapy, at least in a portion of preeclamptic women, to avoid maternal hypertension, fetal distress, oligohydramnios, and IUGR, and consequentially to prolong the gestational period.

Administration, Cutaneous↗
PubMed1999

Pressor response to compression of the ventrolateral medulla mediated by glutamate receptors.

The rostral ventrolateral medulla (RVLM) is considered a major center for the regulation of sympathetic and cardiovascular activities. Several clinical studies have indicated a possible causal relationship between neurovascular contact of the left RVLM and essential hypertension, and some investigators have suggested that the left RVLM is more sensitive to pulsatile compression than the right RVLM. Previously, we reported that pulsatile compression of the RVLM elevates arterial pressure by enhancing sympathetic outflow in rats; however, we have not investigated the laterality of the responses to the compression. In addition, it remains to be elucidated whether RVLM neurons are activated by compression and, if so, how they are activated. Therefore, we performed compression experiments in rats to investigate these issues. Pulsatile compression was performed on the unilateral RVLM with a pulsating probe in anesthetized and artificially ventilated rats. Pulsatile compression of the unilateral RVLM increased arterial pressure, heart rate, and sympathetic nerve activity. The pressor response to compression was inhibited significantly after local microinjection of glutamate receptor antagonists. Pulsatile compression of the RVLM increased Fos immunoreactivitiy, a marker of neuronal activation, within the nuclei of postsynaptic RVLM neurons. All results were observed symmetrically. The data indicate that the responses to pulsatile compression of the unilateral RVLM are similar on both sides. They also suggest that pulsatile compression of the RVLM increases sympathetic and cardiovascular activities by activating postsynaptic RVLM neurons through the stimulation of the local glutamate receptors in rats.

Animals↗
PubMed1999

Scintigraphic evidence for a specific long-chain fatty acid transporting system deficit and the genetic background in a patient with hypertrophic cardiomyopathy.

The mechanism of cardiac uptake of long-chain free fatty acids has not been fully determined. We encountered a hypertrophic cardiomyopathy patient who showed a lack of cardiac uptake of 2 different types of long-chain fatty acid analogues on the scintigraphic images. Flow cytometric analysis revealed no platelet or monocyte CD36 molecule expression (type I CD36 deficiency) and his CD36 gene showed homozygous mutation for 478C to T substitution, leading to an abnormal CD36 amino acid sequence. These findings strongly suggest that a specific transporting system rather than a simple diffusion is commonly involved in the cardiac uptake of long-chain free fatty acids in humans, and that the CD36 protein is the most likely candidate for the specific transporter and to explain scintigraphic defects on fatty acid imaging.

Adult↗
PubMed1999

Effects of single administration of a phosphodiesterase III inhibitor during cardiopulmonary bypass: comparison of milrinone and amrinone.

The effects of phosphodiesterase III (PDE III) inhibitors administered after aortic declamping during cardiopulmonary bypass (CPB) for open heart surgery were investigated. Ten patients (group M) were administered milrinone (50 microg/kg) after aortic declamping during CPB, 10 patients were administered amrinone (1 mg/kg) at the same time during their surgery (group A), and 10 patients served as controls with no drug administered (group C). Soon after bolus infusion of the PDE III inhibitor, perfusion pressure dropped significantly in groups M and A. However, after release of CPB and at the end of surgery, there was no difference in aortic pressure between the 3 groups. There were also no differences between the groups in heart rate, pulmonary artery pressure, and pulmonary capillary wedge pressure. After weaning from CPB, the cardiac index was high and systemic vascular resistance index was low in groups M and A. There were no significant differences in the need for additional catecholamines and time for rewarming between groups. No adverse reactions were observed. A single administration of a PDE III inhibitor during CPB was useful for post-CPB management of patients undergoing open heart surgery. Amrinone reduced perfusion pressures more than milrinone, but cardiac indices and aortic pressures after weaning from CPB showed no differences between group M and group A patients.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1999

Role of hyperinsulinemia in atherosclerotic coronary arterial disease: studies of semi-quantitative coronary angiography.

OBJECTIVE: To evaluate the role of insulin resistance on coronary atherosclerosis, angiographic semiquantitative scores of coronary stenosis and calcification were evaluated. SUBJECTS AND METHODS: Ninety-five non-diabetic subjects with coronary arterial disease were selected from our angiographic data base. Hyperinsulinemia was defined as a serum insulin level of > or = 60.4 IU/l at 120 minutes after 75 g oral glucose challenge. RESULTS: Twenty-three (24%) of the patients exhibited hyperinsulinemia. There was no difference in age or gender between the two subgroups. The incidence of hypertension, smoking habits, hypercholesterolemia, and hyperuricemia were also the same among the insulin resistance subgroups. Subjects with hyperinsulinemia had higher coronary artery scores of stenosis (11.9+/-5.6 vs 8.3+/-5.0, p<0.0001) and calcification (7.5+/-6.3 vs 4.8+/-4.9, p<0.0001). Moreover, the stenosis score had a close linear correlation with the 120 minutes serum insulin level (r=0.266, p=0.009), but not with the fasting level. CONCLUSION: These results suggest that hyperinsulinemia is a risk for coronary arterial disease, and emphasize the severity of coronary atherosclerosis in normal glucose tolerant subjects.

Adult↗
PubMed1999

[A case of nephrotic syndrome with diabetes mellitus and primary aldosteronism].

A 65-year-old man had been followed by a family doctor for the treatment of hypertension and chronic hepatitis (type C) for about 20 years. Although he was pointed out to have impaired glucose tolerance and primary aldosteronism in 1995, he refused an adrenal tumor operation. He was admitted to our hospital on December, 1997 for further evaluation of general malaise, pitting edema of the legs, and positive urinary protein. A diagnosis of nephrotic syndrome was made on admission and a renal biopsy was performed. Histological findings indicated that he was at the early phase of diabetic nephropathy and hypertensive renal sclerosis. It is commonly believed that diabetic nephropathy develops after ten years of diabetic history and under poor control conditions. The diabetic history of this patient was only several years and the disease was under good control. In contrast to blood glucose, hypertension was not well-controlled with any antihypertensive drug, because he had a primary aldosteronism. Unfortunately, he could not take a spironolactone because of side effects. After removal of his adrenal tumor, his blood pressure was normalized gradually, and concomitantly his urinary protein was reduced and plasma protein and albumin were restored. Hypokalemia also disappeared. These findings suggest that uncontrolled hypertension may have accelerated the condition of diabetic nephropathy. The data indicates that the control of hypertension is important for inhibiting the progression of diabetic nephropathy.

Aged↗
PubMed1999

[A case report: disappearance of cancer cells confirmed by surgical resection after transcatheter hepatic artery embolization (TAE) for ruptured hepatocellular carcinoma].

The patient was a 74-year-old man. He had received medical treatment for liver cirrhosis (C types) and elevated AFP. Abdominal ultrasonography (US) revealed a 150 mm size tumor in the right lobe of the liver. After admission, anemia progressed rapidly, and we recognized bloody ascites by abdominal punction. Thus, diagnosis was a tumor rupture. Emergency angiography was performed. Farmorubicin and Lipiodol were injected, and complete TAE was added. After two TAE treatments CT-scan showed a remarkable decrement of the tumor and hypertrophy of the left lobe in the liver. Right lobectomy of the liver was then done because reserve function of the liver was good. Cancer cells changed into hyaline body and mecrotic focus. In the pathological examination of the extirpated sample, no viable tumor cells were detected.

Aged↗
PubMed1999

[Long partial response (PR) in a case of multiple liver metastasis from colon cancer effectively treated by continuous hepatic intra-arterial infusion chemotherapy].

The patient was a 69-year-old man who had undergone a sigmoidectomy for cancer of the sigmoid colon on March 25, 1993. We detected the elevation of CEA after the operation. Computed tomography revealed multiple metastasis of the liver on September 3, 1996. After beginning 48-hour continuous hepatic arterial infusion using 5-FU 1,000 mg and Leucovorin 30 mg, we recognized a decrement of metastatic liver tumor. We could not detect cancer cells by needle biopsy for liver tumors on February 19, 1998. This case is maintaining good quality of life by hepatic artery infusion using 5-FU and Leucovorin, showing a long PR for about two years. We think that this case shows ideal clinical progress from chemotherapy for cancer of the digestive organs.

Adenocarcinoma↗
PubMed1998

Concomitant caudate lobe resection as an option for donor hepatectomy in adult living related liver transplantation.

In this article, we describe a successful adult living related partial liver transplantation (LRLT) using the left lobe with the left-side caudate lobe (the Spiegel lobe and the left side of the paracaval portion). The size of the donor's left lobe was 29% of the recipient's standard liver volume and did not seem to meet our criteria for adult-to-adult LRLT. However, the donor had a thick left-side caudate lobe. The estimated volume of the left lobe with the left-side caudate lobe was 32%, which met our criteria for the adult recipient. The recipient's CT scan on day 87 after transplantation showed the preserved blood flow and no biliary congestion in the left-side caudate lobe, which suggests maintenance of lobe function. This procedure may be an option for adult-to-adult LRLT in which the donor has a thick left-side caudate lobe.

Adult↗
PubMed1998

The cholesterol metabolite cholest-4-en-3-one and its 3-oxo derivatives suppress body weight gain, body fat accumulation and serum lipid concentration in mice.

Based on the findings that cholest-4-en-3-one, an intestinal metabolite of cholesterol, has an anti-obesity effect on animals, the structure-effect relationship of its 3-oxo derivatives and related compounds were investigated. Cholesten-3-ones, which possesses an enone structure with a carbonyl group at C3, markedly inhibit body weight gain and body fat accumulation, as well as the levels of serum triglyceride and cholesterol in animals without any clinical abnormalities.

Adipose Tissue↗
PubMed1998

Visualization of the dynamics of synaptic vesicle and plasma membrane proteins in living axons.

Newly synthesized membrane proteins are transported by fast axonal flow to their targets such as the plasma membrane and synaptic vesicles. However, their transporting vesicles have not yet been identified. We have successfully visualized the transporting vesicles of plasma membrane proteins, synaptic vesicle proteins, and the trans-Golgi network residual proteins in living axons at high resolution using laser scan microscopy of green fluorescent protein-tagged proteins after photobleaching. We found that all of these proteins are transported by tubulovesicular organelles of various sizes and shapes that circulate within axons from branch to branch and switch the direction of movement. These organelles are distinct from the endosomal compartments and constitute a new entity of membrane organelles that mediate the transport of newly synthesized proteins from the trans-Golgi network to the plasma membrane.

Animals↗