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Biomedical subjects

K Tsuda

Publications and source records attributed to K Tsuda.

At least 235 records · Page 13Linked to original sources
PubMed1990

Novel and sensitive enzyme immunoassay (immune-complex-transfer enzyme immunoassay) for alpha-fetoprotein from hepatocellular carcinoma.

Alpha-fetoprotein in sera from patients with hepatocellular carcinoma was fractionated into three peaks by affinity chromatography on a column of Lens culinaris agglutinin-Sepharose 4B. One peak (the first peak), which passed through the column without adsorption, was found in both healthy subjects and patients with liver cirrhosis and hepatocellular carcinoma. The second and third peaks were reactive with L. culinaris agglutinin and found only in patients with hepatocellular carcinoma. For alpha-fetoprotein in the second and third peaks, a novel and sensitive enzyme immunoassay (immune-complex-transfer enzyme immunoassay) was developed. Alpha-fetoprotein in test serum was reacted with dinitrophenyl affinity-purified anti-alpha-fetoprotein IgG, and the complex formed was trapped onto affinity-purified (antidinitrophenyl bovine serum albumin) IgG-coated polystyrene balls. The polystyrene balls were washed to eliminate substance(s) other than alpha-fetoprotein in the test serum, and the complex was eluted from the polystyrene balls with dinitrophenyl-L-lysine. The eluted complex containing alpha-fetoprotein in the second and third peaks was trapped onto L. culinaris agglutinin-coated polystyrene balls and reacted with affinity-purified anti-alpha-fetoprotein Fab'-beta-D-galactosidase conjugate. Beta-D-galactosidase activity bound to the polystyrene balls was assayed by fluorimetry. The maximal volume of serum that could be used without interference was 20 microliters, which was 100-fold larger than that in the previous enzyme immunoassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗
PubMed1990

Enhanced endogenous epinephrine release from the vascular adrenergic neurons in spontaneously hypertensive rats.

This study was performed to investigate the role of endogenous epinephrine in the regulation of vascular tone in hypertension. The release of endogenous epinephrine and norepinephrine from the vascular adrenergic neurons by periarterial nerve stimulation was examined in spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY). The isolated mesenteric vasculatures were prepared, and the epinephrine and norepinephrine release during electrical nerve stimulation was determined as the increase in epinephrine and norepinephrine contents in the vascular perfusate. Epinephrine and norepinephrine were measured by high performance liquid chromatography with an electrochemical detector. Vasoconstrictor responses and norepinephrine overflow during electrical nerve stimulation were significantly greater in SHR than in WKY. The amount of stimulation-evoked epinephrine overflow into the perfusate was also increased in SHR compared to that in WKY, especially at low frequency stimulation. These results suggest that epinephrine could be released from the vascular adrenergic neurons as a cotransmitter of norepinephrine and contribute to increased vascular tone in hypertension.

Animals↗
PubMed1990

Neuropeptide Y and galanin enhance the inhibitory effects of clonidine on norepinephrine release from medulla oblongata of rats.

The medulla oblongata is thought to play an important role in the central regulation of blood pressure. Neuropeptide Y (NPY) and galanin (Gal) coexist with norepinephrine (NE) and may have a functional interaction in this region. The aim of the present study was to investigate whether NPY and Gal could modulate the presynaptic neuronal mechanisms, especially the alpha-adrenoceptor function, inhibiting NE release in medulla oblongata. In slices of rat medulla oblongata, clonidine, an alpha-adrenoceptor agonist, inhibited the NE release elicited by electrical stimulation in a concentration-dependent manner. A combination of clonidine and low concentration of NPY (1 X 10(-9) mol/L) resulted in an increase in the inhibitory action of clonidine on stimulation-evoked NE release. The inhibitory action of clonidine was also potentiated by Gal (1 X 10(-8) mol/L). These results indicate the existence of the presynaptic NPY- and Gal-receptors on noradrenergic nerve terminals, which may enhance the presynaptic alpha-adrenoceptor function to inhibit NE release. This suggests a possible involvement of NPY and Gal in the regulation of sympathetic nerve activity in medulla oblongata.

Animals↗
PubMed1990

The role of protein kinase C and calcium in the regulation of norepinephrine release from the vascular adrenergic neurons in hypertension.

This study was designed to investigate the role of protein kinase C and calcium in vascular adrenergic transmission in hypertension. In perfused mesenteric vasculatures of spontaneously hypertensive rats (SHR, 7 to 10 weeks old) and age-matched Wistar-Kyoto rats (WKY), we have examined the effects of the protein kinase C inhibitor H-7 on endogenous norepinephrine release and vascular responsiveness during nerve stimulation. Endogenous norepinephrine release and pressor responses during periarterial nerve stimulation were significantly greater in SHR than in WKY. The protein kinase C inhibitor H-7 inhibited the stimulation-induced norepinephrine release and pressor responses in a dose-dependent manner. The magnitude of these suppressive responses were more pronounced in SHR than in WKY. Calcium removal from extracellular fluid also reduced the norepinephrine release more strongly in SHR than in WKY. These results demonstrate that the regulation of norepinephrine release might be more dependent on protein kinase C and calcium in the blood vessels of SHR, which could contribute, at least partially, to the pathogenesis of this form of hypertension.

Animals↗
PubMed1990

Enhanced neuroinhibitory effect of diltiazem in blood vessels of spontaneously hypertensive rats.

This study investigated the effects of diltiazem (a Ca2(+)-entry blocker) on neuromuscular junctions of blood vessels in hypertension. In isolated perfused mesenteric vasculatures prepared from spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY), the effects of diltiazem on norepinephrine release from vascular adrenergic neurons and pressor responses were examined. The influences of extracellular Ca2(+)-reduction on these responses were also studied. Stimulation evoked pressor responses and norepinephrine release were significantly greater in the mesenteric vasculatures of SHR than in those of WKY. Diltiazem inhibited both pressor responses and norepinephrine release during electrical nerve stimulation in a dose-dependent manner. The suppression of these responses was more pronounced in SHR than in WKY. Reduction of extracellular Ca2(+)-concentration also decreased the responses in SHR and WKY, and the inhibitory degree was significantly greater in SHR than in WKY. These results demonstrate that diltiazem affected the presynaptic site of the mesenteric vasculatures and decreased the stimulation-evoked norepinephrine release from vascular adrenergic neurons with a concomitant reduction of pressor responses of the preparation. Furthermore, the marked inhibition of pressor responses and norepinephrine release by diltiazem or Ca2(+)-depletion in SHR may suggest the increased Ca2(+)-dependency in vascular neurotransmission in this model of hypertension.

Animals↗
PubMed1990

Age-related changes in membrane fluidity of erythrocytes in essential hypertension.

In the present study, age- and calcium-related changes in the membrane fluidity of erythrocytes were examined in patients with essential hypertension by use of electron spin resonance method (ESR). The erythrocytes were obtained from patients with essential hypertension. We examined the ESR spectra for a fatty acid spin label agent (5-nitroxy stearate) incorporated into the erythrocyte membranes. The values of outer hyperfine splitting and order parameter (S) were significantly higher in subjects with essential hypertension than in the normotensive subjects. This finding indicates that the membrane fluidity of erythrocytes was lower in essential hypertension. Calcium-loading of erythrocytes with the Ca-ionophore A23187 decreased the membrane fluidity (S value was increased) more strongly in essential hypertension than in the normotensive subjects. Furthermore, this Ca-induced change in membrane fluidity was significantly correlated with age in essential hypertension. These results demonstrate that the membrane fluidity of erythrocytes is markedly decreased by calcium, especially in essential hypertension in older patients. This suggests an increased calcium-sensitivity of cell membranes in the aged hypertensive patient.

Aging↗
PubMed1990

Gastroenteritis in suckling mice caused by human rotavirus can be prevented with egg yolk immunoglobulin (IgY) and treated with a protein-bound polysaccharide preparation (PSK).

Oral inoculation of human rotavirus MO strain (serotype 3) into 5-day-old BALB/c mice cause gastroenteritis characterized by diarrhea. Clinical symptoms, histopathological changes in the small intestine, and the detection of rotavirus antigen in enterocytes were all characteristic of rotavirus-induced gastroenteritis. Using this small animal model, passive protection of suckling mice against human rotavirus infection was achieved with the use of immunoglobulin (IgY) from the yolks of eggs of rotavirus-immunized hens. When IgY against a rotavirus strain homotypic to the challenge virus (MO strain) was administered in the mice, complete protection against rotavirus infection was achieved. On the other hand, with oral administration of IgY against a heterotypic strain (serotype 1, Wa strain), a lower protective effect was nevertheless obtained. The four different strains of human rotavirus (Wa, KUN, MO, and ST3) were inactivated in vitro by treatment with PSK, a protein-bound polysaccharide preparation, in a dose-dependent manner. Oral administration of 2.5 mg of PSK caused a therapeutic effect on experimentally MO-infected suckling mice. The antiviral effect of PSK was indicated by the reduction of the duration of diarrhea.

Animals↗
PubMed1990

[Seroepidemiological analysis of the age specific prevalence of anti HTLV-I in Miyazaki Prefecture].

Antibody for HTLV-I in sera from 11,224 residents in Miyazaki Prefecture, Japan, was determined by indirect immunofluorescent antibody method to compare age- and sex-specific antibody prevalence among three geographically divided areas of the prefecture. There was a significant difference in the positive rate of older age groups among three areas, 9.0% for the northern part, 14.5% for the southern part and 8.4% for Miyazaki City, in spite of little variation in younger age groups. A marked rise of positive rate in the southern part at the age of 40th was observed, which suggests that changes of some conditions for mother-to-child transmission happened in the time of their birth. Six seroconversions were observed by the follow-up study for five years of the 971 residents. They were between 28 and 38 years of age, four men and two women. This may provide another reason for the increase in antibody positive rate by age in the adult. However, it could not be investigated if the seroconversion was caused by a horizontal transmission from their spouse. The possibility of the long latency of the virus in man as in the experimental animal may also have to be considered.

Adolescent↗
PubMed1990

[Infections in hematological malignancies--clinical analysis of septic patients admitted to the Second Department of Miyazaki Medical College Hospital in the past ten years].

Two hundred and sixty-two patients (actual number 162) of hematological malignancies were admitted to our department from November 1977 to December 1986. Fourty-three of them (16.4%) were demonstrated to be accompanied with sepsis by blood culture. In acute non-lymphocytic leukemias (AML, APL, AMoL) the rate of sepsis was 33.8% (27 patients), while in lymphocytic malignancies (ML, HD, ATL) it was 11.7% (16 patients), particularly being 3.0% in ATL. Among the detected pathogenic microorganisms, gram-negative bacilli were 86.2% in the former and 50.0% in the latter. Especially, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli occupied 58.6% of the total in the former. Laboratory examination, when sepsis occurred, revealed peripheral neutropenia in acute non-lymphocytic leukemias (mean 831/cmm) but not in lymphocytic malignancy (mean 4,420/cmm). And 20 of the 27 cases showed remarkable neutropenia of below 500/cmm in the former. On the other hand in the latter, out of 16 only one with ATL was the case. Hypogammaglobulinemia was one of the characteristic features in lymphocytic malignancies but not in acute non-lymphocytic leukemias. Hypogammaglobulinemia in lymphocytic malignancies might be affected by long-term immunodepressant therapy. Immunologic skin reaction was demonstrated to be decreased in lymphocytic malignancies on admission. From the findings mentioned above, affecting factors to infections may be mainly neutropenia in acute non-lymphocytic leukemias and immunodeficiency in lymphocytic malignancies. And sepsis can occur frequently under neutropenic condition. In ATL both of humoral- and cellular-immunologic disturbance were detected before therapy. But peripheral neutrophil count was maintained to be normal and this could be the reason for the low septic incidence in ATL despite of total immunodepression.

Agammaglobulinemia↗
PubMed1990

[Clinical and etiological studies of tsutsugamushi disease in Miyazaki district--correlation of serological type of R. tsutsugamushi to clinical feature].

The correlation of pathogenic and immunologic characteristics of Rickettsia tsutsugamushi to clinical findings of patients with tsutsugamushi disease in Miyazaki was investigated. In two immunological types, Hirano type strains seemed to have higher virulence to mice than Irie from the findings during the course of infection and on autopsy. A strain of Hirano type was so virulent as to succumb to the infection. As to clinical findings, incidence of hepatomegaly was slightly higher in Hirano type patients than Irie, which is one of the signs in severe type tsutsugamushi disease. This was supported by the higher mean value and frequent appearance of abnormality in liver function test, sGOT, sGPT and LDH, in this type of patients.

Adolescent↗
PubMed1990

Mechanism of sympathetic neural regulation of insulin, somatostatin, and glucagon secretion.

The effects of electrical stimulation of the left splanchnic nerve on insulin, somatostatin, and glucagon secretion from the isolated perfused rat pancreas were investigated. Electrical splanchnic nerve stimulation (SNS), performed by square-wave impulses, produced a 25% decrease in effluent flow and a 10-fold increase in perfusate norepinephrine. Both insulin and somatostatin output in the presence of 16.7 mM glucose were inhibited during SNS by 85 and 56% of the basal value, respectively. Glucagon output in the presence of 5.5 mM glucose was stimulated 20-fold by SNS. Perfusion with 10(-6) M propranolol further decreased insulin and somatostatin output during SNS, when expressed as the total decrement beneath basal during stimulation. The glucagon response to SNS tended to be enhanced, although not significantly, by simultaneous infusion of 10(-6) M propranolol. However, 10(-6) M phentolamine (Phe) attenuated the SNS-induced inhibition of insulin and somatostatin output by 50 and 40%, respectively. However, insulin output remained decreased after SNS with Phe. The SNS-induced glucagon response was completely abolished by 10(-6) M Phe alone or by 10(-6) M Phe plus 10(-6) M propranolol. With 10(-6) M Phe plus 10(-6) M propranolol, insulin and somatostatin output remained decreased after SNS. These results suggest that insulin and somatostatin secretions induced by glucose are inhibited during SNS through the alpha-adrenergic mechanism and also that the beta-adrenergic mechanism exerts a stimulatory action. SNS-induced glucagon secretion occurs mainly through alpha-adrenergic activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Norepinephrine release and neuropeptide Y in medulla oblongata of spontaneously hypertensive rats.

Neuropeptide Y is colocalized with norepinephrine in both central and peripheral noradrenergic neurons. In this study, we examined the regulatory mechanisms of neuropeptide Y on norepinephrine release in the medulla oblongata of rats. Neuropeptide Y inhibited the stimulation-evoked [3H]norepinephrine release in a dose-dependent manner in slices of medulla oblongata of Sprague-Dawley rats (1 Hz, S2/S1 ratio, control, 0.946 +/- 0.040 [+/- SEM], n = 6; neuropeptide Y 1 x 10(-8) M, 0.676 +/- 0.022, n = 6, p less than 0.05; neuropeptide Y 1 x 10(-7) M, 0.589 +/- 0.014, n = 6, p less than 0.05). Neuropeptide Y potentiated inhibition of [3H]norepinephrine release by the alpha 2-agonists UK 14,304 and clonidine. The blockade of alpha 2-adrenergic receptors by RX 781,094 diminished inhibitory effects of neuropeptide Y on norepinephrine release. Pretreatment of pertussis toxin (a toxin that interferes with the coupling of inhibitory receptors to adenylate cyclase) attenuated the suppression of norepinephrine release by neuropeptide Y. In spontaneously hypertensive rats, the inhibitory effect of UK 14,304 and neuropeptide Y on norepinephrine release from the medulla oblongata was significantly less than in age-matched Wistar-Kyoto rats. These results show that neuropeptide Y inhibits norepinephrine release partially mediated by alpha 2-adrenergic receptors and the pertussis toxin-sensitive guanosine triphosphate-binding proteins in rat medulla oblongata. Furthermore, less suppression of norepinephrine release by UK 14,304 and neuropeptide Y in spontaneously hypertensive rats suggests that alpha 2-adrenergic receptors and neuropeptide Y might be involved in the regulation of central sympathetic tone in hypertension.

Adenylate Cyclase Toxin↗
PubMed1990

Effects of a calcium-antagonist on vascular sympathetic nerve activity in salt-dependent hypertension.

The purpose of the present study was to investigate the effects of a Ca2(+)-antagonist on vascular sympathetic nerve activity in salt-dependent hypertension. Isolated mesenteric vasculature preparations from reduced renal mass-salt hypertensive and age-matched normotensive control rats were used to examine the effects of diltiazem on vascular responsiveness and norepinephrine release from sympathetic nerve endings. Pressor responses and endogenous norepinephrine release during electrical nerve stimulation were significantly greater in preparations from salt-dependent hypertensive rats than from normotensive control rats. Diltiazem inhibited both stimulation-evoked pressor responses and norepinephrine release in a dose-dependent manner. The attenuation of these responses was more pronounced in preparations from rats with salt-dependent hypertension than in those from control rats. These results indicate that norepinephrine release from vascular adrenergic neurons is enhanced in the mesenteric vasculatures of rats with salt-dependent hypertension. The marked reduction of stimulation-evoked pressor responses and norepinephrine release by diltiazem suggests that enhanced Ca2(+)-dependent adrenergic transmission may contribute to the exaggerated vascular sympathetic tone in salt-dependent hypertension.

Analysis of Variance↗
PubMed1990

Importance of imparied insulin-gene expression in occurrence of diabetes in obese rats.

To investigate the role of the beta-cell in the occurrence of diabetes in obesity, longitudinal changes of insulin-gene expression and pancreatic insulin content were compared among genetically obese diabetic (Wistar fatty) rats, genetically obese nondiabetic (Zucker fatty) rats, and ventromedial hypothalamus (VMH)-lesioned obese rats. Plasma glucose levels were significantly elevated with age in Wistar fatty rats, whereas they were virtually unchanged in VMH-lesioned and Zucker fatty rats. Obesity and hyperinsulinemia were evident in VMH-lesioned rats 1 wk after the operation and in Zucker and Wistar fatty rats at 5 wk of age. In VMH-lesioned rats, the pancreatic preproinsulin I mRNA (pplmRNA) level and pancreatic insulin content markedly increased approximately two- to threefold (P less than 0.001) with the development of hyperinsulinemia, whereas sham-operated rats showed no significant change. In Zucker and Wistar lean rats, the pplmRNA level and pancreatic insulin content increased with age, corresponding to increases in body weight. In Zucker fatty rats, the pplmRNA level and pancreatic insulin content at 5 and 14 wk of age were significantly higher than those of lean littermates. The pplmRNA level in Zucker fatty rats at 14 wk of age reached 290% of that of their lean littermates (P less than 0.001). On the other hand, the pplmRNA level and pancreatic insulin content in Wistar fatty rats at 5 and 14 wk of age did not increase more than those of their lean littermates at the corresponding ages and were therefore significantly lower than in Zucker fatty rats, which had a higher grade of hyperinsulinemia at 14 wk of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Finger-pressure waveforms measured on Clynes' Sentograph distinguish among emotions.

We examined the transient finger-pressure when subjects were exposed to the schematic faces which depict "anger," "joy," "sadness," and "no emotion," and to two nonfacial stimuli. In Exp. 1, nine undergraduate women were asked to discriminate between those target stimuli and the nontarget stimuli by pressing on the finger rest of Clynes' Sentograph, without informing subjects that this experiment was to measure emotions. In Exp. 2, the same subjects were asked to express their feelings evoked by the schematic faces by pressing on the finger rest. Results indicate that, even on the discrimination task, the differentiation in the finger-pressure waveforms among emotions was observed. Such differentiation suggests the possibility of measuring the expression of emotions with finger pressure even when the subjects are not aware their emotions are being measured. The identifiable characteristics of the waveforms are the long duration for "sadness" and the strong intensity of pressure for "anger."

Adult↗
PubMed1990

Effects of a protein kinase C inhibitor (H-7) on norepinephrine release from vascular adrenergic neurons in spontaneously hypertensive rats.

This study was performed to investigate the effects of a specific protein kinase C inhibitor (H-7) on vascular adrenergic transmission in hypertension. In the isolated mesenteric vasculature of spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY), we have examined the effects of H-7 on norepinephrine (NE) release from vascular adrenergic neurons. Endogenous NE release during periarterial nerve stimulation was inhibited by H-7 in a dose-dependent manner with a concomitant reduction of pressor responses of the preparation. The inhibition of NE release was not affected by an uptake blocker of NE (desipramine). In SHR, the stimulation-evoked NE release and pressor responses were significantly greater than in age-matched WKY. The suppressive magnitude of stimulation-evoked NE release and pressor responses by H-7 were pronounced in SHR compared with WKY. These results demonstrate that endogenous NE release and pressor responses were increased in the mesenteric vasculature of SHR. Furthermore, the marked inhibition of NE release and pressor responses by H-7 in SHR may suggest the presence of enhanced protein kinase C-dependent regulation of vascular adrenergic transmission, which may contribute to the calcium-related abnormalities in this form of hypertension.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗