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Biomedical subjects

K Nakai

Publications and source records attributed to K Nakai.

At least 325 records · Page 18Linked to original sources
PubMed1986

The distribution of adrenergic receptors in cerebral blood vessels: an autoradiographic study.

The first morphological evidence of the existence of adrenergic receptors (alpha 1, alpha 2 and beta) within the vascular walls of the central nervous system were presented using the in vitro receptor autoradiographic technique. In the rat pial arteries all three types of adrenergic receptors were demonstrated, whereas the human pial arteries failed to show significant autoradiographic grains of alpha 1 type of adrenergic receptors indicating a considerable inter-species difference in the distribution of adrenergic receptors. alpha 2 and beta receptors in human pial arteries were found not only in the arterial smooth muscle layers but also in the endothelial layers. This suggests a possibility that circulating sympathomimetic agents play some role in controlling the tone or permeability of vascular walls within the central nervous system. A distinct distribution of alpha 1 receptors in cortical layer IV where the vascular plexus was richest may suggest a relation of alpha 1 receptors and blood flow of brain parenchyma.

Animals↗
PubMed1986

Three dimensional observation of the nerve fibers along the cerebral blood vessels.

Three dimensional observation of the nerve fibers along the cerebral blood vessels was investigated by scanning electron microscopy. Electron probe X-ray microanalysis was also performed in the cerebral blood vessels treated with peroxidase-antiperoxidase immunohistochemistry intensified by nickel ammonium sulfate. Nerve fibers (2-8 microns in diameter) formed a plexus on the outer surface of the adventitia. After branching, the nerve fibers penetrated the blood vessel adventitia. Substance P-immunoreactive nerve fibers showed a meshwork pattern in the outer layer of the adventitia, and vasoactive intestinal polypeptide (VIP)-immunoreactive nerve fibers revealed a spiral running pattern in the inner layer of the adventitia. Taken together with previous studies, these findings suggest that substance P nerve fibers in the cerebral arteries may not be related to arterial dilatation or constriction, but VIP nerve fibers may be vasodilative.

Animals↗
PubMed1986

Quantitative analysis of global and regional cardiac performance in normal subjects and patients with coronary artery disease by rest/exercise radionuclide blood-pool study.

This study was undertaken to assess regional and diastolic left ventricular (LV) function in relation to LV asynchronous contraction during exercise (Ex). Rest and serial Ex (25w-75w) gated blood-pool study (Tc-99m-RBC) of 6 normal subjects (N), 12 patients with stable angina pectoris (AP) and 8 with LV aneurysm (LVan) were evaluated in regional LV ejection fraction (EF) and Fourier analysis using higher-order harmonics. In the patients with Ex and regional EF showed various responses to Ex. Global LVEF in the patients with AP indicated almost no change during Ex and regional EF declined apparently in anteroseptal segment, corresponding to stenotic left anterior descending artery. Diastolic indices of regional and global cardiac performance, PFR (peak filling rate), TPF (time to PFR) and standard deviation (SD) of TPF histogram, were obtained by Fourier analysis using two-order harmonics. Patients with coronary artery disease (CAD) showed significantly lower PFR, longer TPF and higher SD of TPF than normal group, suggesting asynchronous relaxation. We conclude that regional EF response and diastolic indices of cardiac performance to exercise provide useful and sensitive information detecting the severity of CAD.

Adult↗
PubMed1986

A role of the central catecholamine neuron in cerebral circulation.

The effect of the central catecholaminergic neurons on the cerebral microcirculation was investigated by means of a unilateral intracerebral injection of 6-hydroxydopamine (6-OHDA) which produced the degeneration of catecholamine (CA) nerve terminals. Subsequent observation with CA histofluorescence revealed an absence of CA fibers in the vicinity of the 6-OHDA injection site. A significant increase in regional cerebral blood flow (rCBF), measured by the hydrogen clearance method, was demonstrated in the CA-depleted cortex under normocapnia as compared with rCBF in the control cortex (CA-depleted cortex 47.0 +/- 2.8 ml/100 gm/min; control cortex 38.5 +/- 3.5 ml/100 gm/min; p less than 0.005). The increased rCBF in the cortex treated with 6-OHDA was suppressed by the iontophoretic replacement of noradrenaline (NA) to the CA-depleted cortex. An iontophoretic replacement of 10(-5) M dopamine (DA) mildly suppressed the increased rCBF in the 6-OHDA-treated cortex. The CO2 reactivity in the CA-depleted cortex was significantly lower than that of the control cortex (CA-depleted cortex 2.13% +/- 0.6%/mm Hg; control cortex 3.53% +/- 0.70%/mm Hg). No change was noticeable in the cerebral glucose metabolism in the CA-depleted cortex in an investigation based on tritiated (3H)-deoxyglucose uptake. It is suggested that the 6-OHDA-induced change in cerebral blood flow (CBF) is not secondary to alterations in cerebral metabolic rate, and that the central NA neuron system innervating intraparenchymal blood vessels regulates CBF through a direct vasoconstrictive effect on the cerebral blood vessels. The central DA neuron system may modulate the cerebral circulation as a mild vasoconstrictor.

Animals↗
PubMed1986

[Chemotherapy of renal cell carcinoma. 2. Combined chemotherapy using ACNU and VBL].

Nineteen patients with renal cell carcinoma who had undergone radical nephrectomy have been treated with a combination of chemotherapy and partly hormonal therapy using ACNU, vinblastine and chloromadinone acetate. The efficacy of the combination therapy in advanced renal cell carcinoma was studied and only one out of nineteen cases having lung and pleural metastasis shows no change lasting from one to eighteen months. The prophylactic efficacy was studied in eighteen patients with stage I to IVA renal cell carcinoma (contained one patient with stage IVA renal cell carcinoma who had undergone radical nephrectomy and coecum resection for coecum invasion). Tumor recurrence occurred in 5 cases, that is 5 cases within 1 year and 1 case within 2 years. The combination of chemotherapy using ACNU & vinblastine must be used carefully for severe side effects.

Adult↗
PubMed1985

Effects of hyperphenylalaninemia in the fetal stage on the postnatal development of fetal rat brain.

The effect of exposure at different prenatal stages to maternal hyperphenylalaninemia (HyPhe) on the somatic and neurological development of fetuses in rats was studied, with special respect to the change of relevant enzyme activities in the brain. While evident somatic damage was found only in the fetuses exposed to maternal HyPhe at a last stage of gestation, distinct mental retardation seemingly due to some irreversible damage to the brain was observed in all the treated fetuses regardless of the timing of exposure, and a significantly reduced activity of 2', 3'-cyclic nucleotide 3'-phosphohydrolase (CNPase), a marker enzyme of myelin, was confirmed in the mantle region of the brain.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1985

Comparison of pulmonary accumulation of pyrilamine and pyrilamine N-oxide.

Our previous studies have indicated that a phenothiazine drug, chlorpromazine, and a tricyclic antidepressant, imipramine, are metabolized by the isolated perfused rat lungs via N-oxidation from whence their N-oxides are released into the circulation. This work was undertaken to compare the pulmonary accumulation of another pneumophilic tertiary amine drug, pyrilamine, with that of its N-oxide. Approximately 10-fold greater accumulation of pyrilamine than that of its N-oxide was observed in the mouse lung after a single pass perfusion with 40 microM of the drug for a 3 min period. The largest difference between accumulation of pyrilamine and its N-oxide was noted in the lung among the various tissue slices tested, suggesting the tissue specificity of affinity.

Aminopyridines↗
PubMed1985

5-Hydroxytryptamine innervation of vessels in the rat cerebral cortex. Immunohistochemical findings and hydrogen clearance study of rCBF.

The role of the central 5-hydroxytryptamine (5-HT) neuron system in cerebral microcirculation of the rat was examined by immunohistochemical and hydrogen clearance methods. Immunohistochemical studies demonstrated 5-HT-immunoreactive nerve fibers along intraparenchymal blood vessels (arterioles, capillaries, and venules). Ultrastructural observation revealed that 5-HT-immunoreactive terminal boutons (0.3 to 1.0 micron in diameter) made contact with the basement membrane of the capillaries. After an intracerebral injection of 5,7-dihydroxytryptamine (5,7-DHT), a neurotoxin to the 5-HT neuron system, no 5-HT-immunoreactive nerve fibers were found around the injection site with immunohistochemical techniques. With the hydrogen clearance method, the 5,7-DHT-injected cortex showed no significant change in regional cerebral blood flow (rCBF) in the presence of normocapnia, but a significant increase in rCBF with hypercapnia, compared with the untreated cortex. These facts strongly suggest that the central 5-HT neuron system has an important role in carbon dioxide reactivity of the cerebral blood vessels.

Animals↗
PubMed1985

[Therapy of renal cell carcinoma. 1. Hormonal therapy].

Sixty eight patients with renal cell carcinoma were treated at our University in 1968 approximately 1983. The prognosis of these patients was studied retrospectively. Sixty six patients had also been receiving treatment with chemotherapy or radiotherapy except 3 cases after radical nephrectomy. Thirty five of the patients with Stage I approximately N renal cell carcinoma were treated with hormonal therapy using chlormadinone acetate (CMA) or medroxyprogesterone acetate (MPA). CMA was used prophylactically in 21 patients with Stage I approximately IIIA renal cell carcinoma and who had undergone radical nephrectomy. Metastasis was noted in 3 cases in this prophylactic CMA group (21 cases) and 4 cases in the control group (19 cases). No significant difference between these two groups was observed statistically. In the advanced group with Stage IIIC-IV renal cell carcinoma (11 cases), only one case with a complete response was noted after CMA combination therapy.

Adult↗
PubMed1985

[Study on voiding disturbance in elderly males. II. Analysis of the patterns in uroflowmetric studies in patients with obstructive diseases in lower urinary tract and neurogenic bladder].

Uroflowmetry was examined in 192 patients with obstructive urinary symptoms. They were 173 males with obstructive diseases in lower urinary tract (302 uroflowmetric studies) and 19 males with neurogenic bladder (29 uroflowmetric studies). We classified the patterns of uroflowmetric curve into 6 types: N type (normal), NB type (neurogenic bladder: wave like curve), OB type (obstructive diseases: flat curve), AP type (anterior peak), PP type (posterior peak) and OT type (others). The 331 uroflowmetric curves were classified into the above 6 types, and the relationship between each type of flow curve and other uroflowmetric parameters (voided volume = VV, residual urine volume = RU, maximum flow rate = MFR, average flow rate = AFR) was analyzed. The types of 229 flow studies (140 patients) in benign prostatic hypertrophy were OB (77.7%), AP (16.6%), OT (3.9%), N (0.9%) and PP (0.9%). The types of 39 flow studies (25 patients) in prostatic cancer and 13 studies (8 patients) in urethral stricture were similar; 92.3% of the flow studies being classified into OB type. The types of 21 flow studies (10 patients) in so-called bladder neck contraction were OB (42.9%), AP (33.3%), OT (14.3%) and NB (9.5%). AP type flow curves were more frequent than other in obstructive diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗