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Biomedical subjects

Y Koide

Publications and source records attributed to Y Koide.

At least 253 records · Page 14Linked to original sources
PubMed1982

Inhibition by trifluoperazine of glycogenolytic effects of phenylephrine, vasopressin, and angiotensin II.

The effects of trifluoperazine on the activation of glycogenolysis by various hormones were studied in perfused rat liver. Trifluoperazine significantly inhibited glycogenolytic effect of phenylephrine and angiotensin II by lowering maximal response, and that of vasopressin by shifting the dose-response curve to the right, while alpha-antagonist phentolamine was inhibitory only to phenylephrine. Phosphorylase activation of phenylephrine was inhibited by trifluoperazine in parallel with glycogenolytic response. The increase in 45Ca2+ efflux induced by phenylephrine, angiotensin II, and vasopressin was also inhibited by the agent. These inhibitory effects of trifluoperazine were not related to the change in tissue cyclic AMP or cyclic GMP levels. On the other hand, neither the glycogenolytic effect of glucagon, cyclic AMP, and N6,O2-dibutyryl cyclic AMP nor phosphorylase activation by glucagon was affected by trifluoperazine. Thus, trifluoperazine specifically inhibits the activation of glycogenolysis by Ca2+-dependent hormones.

Angiotensin II↗
PubMed1982

A case of cerebrotendinous xanthomatosis: effects of ursodeoxycholic acid administration on serum bile acids and cholestanol.

Cerebrotendinous xanthomatosis (CTX) is a rare familiar disease characterized by tendon xanthomas, cataracts, cerebellar ataxia, dementia and an elevated serum cholestanol level. In this paper, a 50-year-old man with typical signs and symptoms of CTX is described. Serum cholestanol and chelesterol concentrations were 17.9-28.6 micrograms/ml and 109-153 mg/dl, respectively. The determination of non-sulfated bile acid concentration in the serum assayed by mass fragmentography disclosed an abnormal profile. The concentration of cholic acid (0.30-0.52 microgram/ml) was higher than normal, while those of chenodeoxycholic acid, ursodeoxycholic acid, deoxycholic acid and lithocholic acid were extremely low or undetectable. Administration of ursodeoxycholic acid (300 mg per day, orally) for 2 weeks resulted in a marked reduction of serum cholic acid concentration. However, serum cholestanol levels remained unchanged.

Bile Acids and Salts↗
PubMed1982

The role of three distinct Ia-like antigen molecules in human T cell proliferative responses: effect of monoclonal anti-Ia-like antibodies.

Murine monoclonal antibodies (MoAb) to three distinct Ia-like molecules were studied for their inhibitory effects on antigen- and alloantigen-induced T cell proliferations. The MoAb were classified into three groups according to the molecules they recognized. Both the group I MoAb reacting with DR molecules and the group III MoAb were capable of inhibiting T cell proliferative responses to PPD- and HSV-Ag-pulsed APC, autologous B-LCL, and alloantigens. On th other hand, the group II MoAb, which reacted with a determinant on the molecule carrying MB1 determinants, was only capable of inhibiting T cell responses to alloantigens. These results suggest that the structure of the molecules correlates with the functional repertoire of the human Ia-like antigens.

Antibodies, Monoclonal↗
PubMed1982

[P-hydroxyphenylacetic acid concentrations in cerebrospinal fluid].

Using reversed-phase high-performance liquid chromatography and electrochemical detection with a rapid one-step purification on Sephadex G-10 column, we have developed a sensitive technique to measure p-hydroxyphenylacetic acid (PHPA), the oxidatively deaminated metabolite of p-tyramine, in cerebrospinal fluid (CSF). The method has been shown to offer simplicity, high sensitivity and low cost for the analysis of PHPA. By using this method PHPA can be measured concurrently with the dopamine metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in small amounts of CSF (0.5 ml or less). The concentrations of PHPA ranged 4.2 to 17.0 ng/ml with a mean value of 7.8 ng/ml+/-1.1 SEM in lumbar CSF of non-neurological control patients. PHPA value is consistent with the results of earlier studies using different methods. PHPA concentrations in both schizophrenic (4.7+/-0.6 ng/ml, n=11) and epileptic patients (5.8+/-0.4 ng/ml, n=28) were significantly lower than those in control patients. A concentration gradient of PHPA was found along the ventricular-lumbar axis. Probenecid markedly increased PHPA in lumbar CSF. These observations suggest that PHPA in lumbar CSF is derived at least in part from the brain and eliminated from CSF by a probenecid-sensitive transport mechanism. There was a significant correlation between PHPA and HVA concentrations in CSF. This is an interesting finding since a reciprocal relationship between dopamine turnover and p-tyramine concentrations has been found in the striatum of experimental animals. A number of recent studies suggest that p-tyramine may act as neurotransmitter or neuromodulator in specific neuronal systems. The present method should be useful in clinical investigations to clarify a functional role of p-tyramine in the brain.

Adolescent↗
PubMed1981

Both HLA-DR restricted and nonrestricted functions of adherent cells are required for induction of T lymphocyte proliferative responses.

There appeared to be two distinct functions of adherent cells in human T lymphocyte proliferative responses to purified protein derivative (PPD). The first is antigen-presenting ability which is mediated by antigen-presenting cells (APC) among adherent cells. By employing antiserum blocking pretreatment of APC, it was revealed that HLA-DR antigens are involved in this function and that identity or partial identity of HLA-DR antigens between APC and T lymphocytes is required for T lymphocyte antigen recognition. The second function is mediated by the soluble factor produced by adherent cells and is HLA-DR nonrestricted. Although it remains unclear whether APC and adherent cells producing the soluble factor belong to the same cell population, this second function might lead T lymphocytes to proliferative as long as T lymphocytes recognize antigen (PPD) via APC.

Animals↗
PubMed1981

The importance of local hemostatic procedures in dental extractions and oral mucosal bleeding of hemophiliac patients.

Deficient coagulation factor replacement therapy is often indispensable for dental extractions and oral mucosal bleeding in hemophiliac patients. High concentrates are often infused in large amounts of volume, until complete hemostasis is achieved. Considering the various side effects of replacement therapy the volume infused should be reduced to a minimum. Several aspects associated with replacement therapy for the control of oral bleeding are studied. Our conclusion is that local hemostatic procedures are even more important than replacement therapy. The use of surgical packs and band retainers proved to be of benefit in this study.

Adolescent↗
PubMed1981

Human antigen-presenting cells: characterization of the cells in the T-lymphocytes proliferative response.

Human antigen-presenting cells (APC) which present the antigen to T lymphocytes resulting in a T-lymphocyte proliferative response were found among peripheral mononuclear cells (MNC), by employing purified protein derivative (PPD) as soluble antigen. To assess the adherence capacity of human antigen-presenting cells, MNC were separated by plastic Petri dishes or nylon wool columns. Plastic nonadherent cells were almost equivalent to unseparated cells in antigen-presenting ability. Plastic adherent cells, however, showed better antigen-presenting ability than unseparated cells. On the other hand, cells passed over nylon wool columns showed essentially no ability to present PPD to T lymphocytes. Removal of phagocytic cells by carbonyl iron resulted in about 50-70% reduction in antigen-presenting ability. Carrageenan, which is known to be toxic to macrophages, had no effect on APC. By using both rabbit anti-human Ia-like antiserum and alloantiserum specific for HLA-DR phenotype and complement, it was shown that APC possessed Ia-like antigens, whereas they did not bear surface immunoglobulins. These results indicate that the human APC is probably a cell in the monocyte-macrophage lineage. Allogeneic MNC were used as APC in order to determine whether any genetic restriction exists between MNC as APC and responding T lymphocytes. Optimal stimulation was shown to require identity of mixed leukocyte reaction (MLR)- activating determinants between APC and T lymphocytes. It is however, obscure whether an HLA-D region restriction exists in these combinations because PPD-pulsed allogeneic MNC lost their ability to elicit even MLR. It is possible that this failure to elicit MLR was caused by T lymphocytes among the MNC used as APC.

Antigens↗
PubMed1981

Kinetic aspects of monoamine oxidase activity in twins with psychoses.

Monoamine oxidase activity was assayed in platelets from 22 (8 monozygotic and 14 dizygotic) twin pairs. At least one twin of each pair had a serious psychiatric disorder (proband). Phenethylamine was used as substrate and the assay was performed at two different oxygen concentrations (0.06 and 0.12 nM). Apparent Km and Vmax values were estimated from double reciprocal plots. The correlation between proband and control twins was high for both apparent Km (r = 0.83) and Vmax (r = 0.69) when the enzyme was assayed at the higher concentration of oxygen. The monozygotic twins pairs showed very high correlations (Km r = 0.93; Vmax r = 0.86) as compared to dizygotic twins (Km r = 0.81, Vmax r = 0.50) and apparently healthy subjects (Km r = 0.46, Vmax r = 0.33). No difference in kinetic properties was found between schizophrenic and non-schizophrenic twins.

Blood Platelets↗
PubMed1981

Activity of platelet monoamine oxidase in apparently health subjects.

Monoamine oxidase activity was assayed in platelets from 32 apparently healthy subjects using phenethylamine as substrate and two concentrations of oxygen (0.06 and 0.12 mM). Apparent Km (microM) and Vmax (nmol/mg protein/5 min) values were estimated from double reciprocal plots. The means of the Km and Vmax values were both increased by a factor of about 1.6 when the oxygen concentration was elevated from 0.06 mM (Km = 2.96 and Vmax = 4.47) to 0.12 mM (Km = 4.82 and Vmax = 7.18). The frequency distribution of the Vmax values was not clearly unimodal, especially at the higher oxygen concentration. The Vmax values of the women were significantly higher than those of the men but no sex difference was obtained for the Km values. The overall velocity (v) at 10 microM phenethylamine was highly correlated to the Vmax values both at low and high oxygen concentrations (r = 0.99 and 0.98, respectively).

Blood Platelets↗
PubMed1981

Platelet monoamine oxidase activity in schizophrenic families - kinetic aspects.

Monoamine oxidase activity (MAO) was determined in platelets in samples from a North-Swedish pedigree with a high frequency of schizophrenia. The MAO assay was performed with phenethylamine as substrate and with two concentrations of oxygen (0.06 and 0.12 mM). A tendency to lowered Vmax and increased apparent Km values was observed among the schizophrenic subjects, although there were no statistically significant differences in apparent Km and Vmax values between schizophrenics and their non-schizophrenic relatives.

Blood Platelets↗
PubMed1981

Evidence for acute inhibitory effects in vivo of 1 alpha-hydroxycholecalciferol on parathyroid hormone secretion in rats.

In an attempt to elucidate the influence of 1 alpha-hydroxycholecalciferol (1 alpha OHD3) on parathyroid hormone (PTH) secretion, sequential measurements were made of 1) serum calcium and urinary excretion of cAMP in conscious perfused rats, and 2) serum calcium in nephrectomized rats; also, the effects of a single iv injection of 1 alpha OHD3 on these parameters were examined. In conscious perfused rats, 6.25 micrograms/kg (15 nmol/kg) 1 alpha OHD3 reduced the urinary excretion of cAMP (approximately 40% of the initial value; P less than 0.05), which reached a level compatible with that of parathyroidectomized rats at 4 h; this fall was sustained for 24 h. Serum concentrations of calcium (total and ionized) did not change at 6 h, and increased at 24 h. In parathyroidectomized rats which were continuously infused with bovine PTH (0.75 U/h), the vitamin D preparation had no significant effect on the urinary excretion of cAMP. Nephrectomy, followed by an injection of the vehicle (0.05 ml 99.5% ethanol), induced a transient hypercalcemia (13.12 +/- 0.39 mg/dl at 6 h). This hypercalcemic response was prevented by prior parathyroidectomy. Injections of 1.25 and 6.25 micrograms/kg 1 alpha OHD3 caused a significant suppression of the hypercalcemia (P less than 0.05 and P less than 0.1, respectively) in the presence of parathyroid glands, whereas a dose-related hypercalcemic effect was observed in their absence. These results suggest that in rats, 1 alpha OHD3, either directly or most probably after conversion into 1 alpha, 25-dihydroxycholecalciferol, 1) acutely inhibits PTH secretion without causing a significant rise in serum calcium, and 2) suppresses PTH secretion in secondary hyperparathyroidism induced by nephrectomy.

Animals↗