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Biomedical subjects

S Seto

Publications and source records attributed to S Seto.

At least 55 records · Page 3Linked to original sources
PubMed1996

Effects of menopause on trends of serum cholesterol, blood pressure, and body mass index.

BACKGROUND: To elucidate the impact of menopause on coronary risk factors, we determined the trends of serum cholesterol (mg/dL), blood pressure (BP, mm Hg), and body mass index (BMI, kg/m2) and investigated whether menopause affects these trends in women in Nagasaki, Japan. METHODS AND RESULTS: Trends of cholesterol, systolic BP (SBP), and BMI from 9 years before menopause through 9 years after menopause in 579 women with natural menopause (ranging in age from 40.2+/-3.1 to 57.9+/-3.1 years; age at menopause, 49.4+/-3.0 years) and 134 women with surgical menopause (hysterectomy with or without bilateral oophorectomy; ranging in age from 34.9+/-4.5 to 51.7+/-5.1 years; age at menopause, 42.9+/-5.0 years) and those in 579 and 134 age- and time-matched male subjects (ranging in age from 40.1+/-3.1 to 57.8+/-3.2 years and from 35.2+/-4.5 to 51.6+/-5.0 years, respectively) in Nagasaki were determined by rearrangement of the data from 1958 to 1989 with time of menopause as the datum line. Although cholesterol tended to increase with age in both sexes, it increased significantly in women from 3 years before natural menopause to 1 year after natural menopause and from 1 year before surgical menopause to 1 year after surgical menopause. SBP and BMI did not exhibit a significant increase in relation to natural or surgical menopause. In male subjects, no significant increase of cholesterol, SBP, or BMI was observed at the age corresponding to natural or surgical menopause. CONCLUSIONS: Natural menopause and surgical menopause exert an effect only on cholesterol, and an increase in cholesterol precedes natural menopause by 3 years and occurs at the time of surgical menopause.

Adult↗
PubMed1996

Continuous HGF supply from HGF-expressing fibroblasts transplanted into spleen prevents CCl4-induced acute liver injury in rats.

Hepatocyte growth factor (HGF), first identified as a potent mitogen for mature hepatocytes, has been reported to have various activities. We investigated protective effect of continuous HGF supply on carbon tetrachloride (CCl4)-induced acute liver injury in rats. We transfected immortalized but not tumorigenic rat fibroblasts (Rat-1) with an expression plasmid containing the human HGF cDNA and established several cell lines expressing HGF. The biological activity of HGF produced by these cell lines was confirmed by its mitogenic effect on rat hepatocytes in vitro. Either one of the high-HGF-producer cell lines or parental Rat-1 cell line was transplanted into a syngenic rat spleen. Twelve days after transplantation, each rat was intraperitoneally injected with CCl4 and sacrificed 48 h after CCl4 injection. In rats with continuous HGF supply significantly lower serum glutamic-pyruvic transaminase (GPT) level was observed compared to its marked elevation in control rats and the degree of hepatocyte damage was slight on histological analysis. These results indicate that continuous HGF supply effectively inhibits CCl4-induced acute liver injury and may suggest the possibility that this system would be useful on various liver diseases.

Alanine Transaminase↗
PubMed1996

Evidence that implicates the parathyroid hormone-related peptide in vascular stenosis. Increased gene expression in the intima of injured carotid arteries and human restenotic coronary lesions.

Proliferation of vascular smooth muscle cells (VSMCs) is considered to be one key event underlying the pathophysiology of restenosis after angioplasty. The parathyroid hormone-related peptide (PTHrP) and its receptor, a local autocrine and paracrine regulator of cellular growth in a variety of normal cell types, have been reported in the vicinity of VSMCs. To investigate how PTHrP might be involved in the process of neointimal formation after balloon angioplasty, we examined PTHrP expression in balloon-denuded rat carotid arteries and human coronary arteries that had been retrieved by directional atherectomy. In rat carotid arteries, the RNase protection assay and in situ hybridization demonstrated that PTHrP mRNA expression increased fourfold to sixfold 1 to 7 days after denudation and continued for 28 days, coincident with downregulation of PTH/PTHrP receptor mRNA expression. In situ hybridization and immunohistochemistry revealed that PTHrP expression in balloon-denuded carotid arteries was mainly localized to the neointima. To confirm the involvement of the PTHrP in human coronary artery restenotic lesions, immunohistochemical analysis of human coronary atherectomy specimens (23 primary and 10 restenotic lesions) was then performed. The number of intimal cells that expressed PTHrP protein was significantly higher in restenotic (407 +/- 53 cells/mm2; range, 143 to 739) than in stable angina (50 +/- 12 cells/mm2; range, 18 to 132; P<.05) or unstable angina (129 +/- 16 cells/mm2; range, 21 to 232; P<.05) specimens. These data demonstrate that PTHrP gene expression in VSMCs markedly increases during neointimal formation, supporting the hypothesis that PTHrP may play an important role in vascular stenosis as a regulator of VSMC proliferation.

Adult↗
PubMed1996

Adenoid cystic carcinoma arising in the intrapulmonary bronchus.

A 63-year-old male was admitted to our hospital because of a coin lesion in the intrapulmonary bronchus. The patient had no symptoms such as cough or sputum. Imaging studies showed that the tumor was present in the S10b,c of the right lung. There was no metastasis or salivary gland tumor. Transbronchial tumor biopsy revealed a primary adenoid cystic carcinoma. The patient underwent a lobectomy, and has been well since the operation. This is an uncommon case of primary adenoid cystic carcinoma arising from the intrapulmonary bronchus.

Bronchial Neoplasms↗
PubMed1995

Highly-sensitive identification of alpha-fetoprotein mRNA in circulating peripheral blood of hepatocellular carcinoma patients.

In order to capture hepatocellular carcinoma (HCC) cells in circulating peripheral blood, we made analysis to see if alpha-fetoprotein (AFP) mRNA exists in the peripheral blood obtained from patients with HCC and also, as a control, from hepatitis-viral-marker-positive patients without HCC and a healthy volunteer. As the number of HCC cells in peripheral blood and the quantity of AFP mRNA are expected to be very small, the analysis was performed by the reverse transcription followed by an original three-step polymerase chain reaction. By this highly-sensitive method, 5 of 7 HCC patients were positive for AFP mRNA. These 5 positive patients consisted of three with clinically apparent recurrence, one preoperative patient with tumor thrombus in the portal vein and one recurrence-free patient who developed clinically detectable recurrence three months after this analysis. Neither 4 patients with positive viral markers nor a healthy volunteer was positive. The results suggest that detection of AFP mRNA from HCC patients' peripheral blood by our highly-sensitive RT-PCR may be a practical and powerful tool to diagnose the preoperative spreading of HCC and to monitor its recurrence.

Adult↗
PubMed1995

Transient dilatation of the abdominal aorta in an infant with Kawasaki disease associated with thrombocytopenia.

We report on an 8 month old infant with Kawasaki disease associated with giant coronary aneurysms and transient thrombocytopenia. The patient's platelet count decreased to 24,000/mm3 on the 31st day of illness and fibrin degradation product was 5 micrograms/mL. Platelet count increased to the normal level (357,000/mm3) on the 35th day of illness. On the 27th day of illness, dilatation of the distal abdominal aorta adjacent to the bifurcation of the iliac arteries was observed by B-mode and color Doppler ultrasonography. It gradually returned to a normal size by the 45th day of illness. Aspirin administered from the 3rd to the 26th day of illness was replaced with flubioprophen because of liver dysfunction. Although we can not eliminate aspirin allergy as the cause of the transient thrombocytopenia, we think that the thrombocytopenia may have been related to the regression of the abdominal aorta.

Aortic Aneurysm, Abdominal↗
PubMed1995

Electrophysiological evidence for overlapping dominant and latent inputs to somatosensory cortex in squirrel monkeys.

1. The pattern of reorganization in area 3b of adult primates after median or ulnar nerve section suggests that somatic afferents from the dorsum of the hand, carried by the radial nerve, have preferential access to the cortical territories normally expressing glabrous inputs carried by the median and ulnar nerves. A likely mechanism underlying preferential access is preexisting, but silent, radial nerve inputs to the glabrous region of cortex. 2. We tested this by comparing the effects of electrical stimulation of median or ulnar versus radial nerves, on responses in the hand representation of area 3b. Laminar current source density and multiunit activity profiles were sampled with the use of linear array multicontact electrodes spanning the laminae of area 3b. Data were obtained from three squirrel monkeys anesthetized during recording. 3. Compared with colocated median or ulnar nerve responses, the radial nerve response had 1) an initial short-latency response in the middle laminae that was subtle; there was a small transmembrane current flow component without a discernable multiunit activity correlate; and 2) a laminar sequence and distribution of activity that was similar to those of the median or ulnar nerve responses (i.e., initial activation of the middle, followed by upper and lower laminae), but the significant current flow and multiunit response to radial nerve stimulation occurs 12-15 ms later. 4. Normal corepresentation of nondominant dorsum hand (radial) inputs with the dominant (median or ulnar) inputs in the glabrous hand surface representation provides a clear vehicle for the biased patterns of reorganization occurring after peripheral nerve section. The initial, "subtle" activity phase in the nondominant response is believed to reflect intracortical inhibition, and the later "significant" response phase, a rebound excitation, possibly compounded by an indirect or extralemniscal input. The spatiotemporal pattern of nondominant input is proposed to play a role in normal somatosensory perception.

Action Potentials↗
PubMed1995

[A case of sacral neuroblastoma in an adult successfully treated with combination chemotherapy].

A 35-year-old woman was admitted with complaints of severe posterior femoral pain and was diagnosed as having sacral neuroblastoma by tumor open biopsy. After admission, combination chemotherapy consisting of CDDP, etoposide, CPA, and THP was started intra-arterially and intravenously. After 2 courses of chemotherapy, her symptoms markedly improved and the tumor size was reduced. Now, after completion of 16 courses of chemotherapy, she is in a state of partial remission. Hereafter, we intend to reconsider the treatment strategy including surgical therapy.

Adult↗
PubMed1994

Chronic hyperinsulinemia augments deoxycorticosterone acetate-salt hypertension.

To evaluate the effect of chronic hyperinsulinemia on blood pressure in salt-dependent hypertension, we infused insulin (1.0 IU/d, n = 15) or saline (n = 13) for 4 weeks into deoxycorticosterone acetate-salt hypertensive rats. The insulin infusion increased plasma insulin levels to 24 +/- 2 microU/mL, which was higher than in the saline-infused rats (9 +/- 1 microU/mL) but was still within the physiological range. Blood pressure was measured by the tail-cuff method twice a week, and daily sodium intake and urinary sodium excretion were calculated for 3 weeks. At week 4, arterial pressor responsiveness to norepinephrine, angiotensin II, and hexamethonium bromide was evaluated. After 14 days of chronic infusion, the insulin group showed a higher blood pressure than the saline group (on 21st day: 178 +/- 6 versus 156 +/- 5 mm Hg, P < .05 by tail-cuff method; 171 +/- 4 versus 149 +/- 3 mm Hg, P < .05 by direct intra-arterial measurement). This blood pressure difference was eliminated after ganglionic blockade with hexamethonium bromide (86 +/- 4 mm Hg in insulin-treated and 89 +/- 4 mm Hg in saline-treated rats by direct intra-arterial measurement). Throughout the experiment, neither sodium balance nor arterial pressor responsiveness to norepinephrine or angiotensin II differed between the two groups. In conclusion, chronic hyperinsulinemia in the physiological range augments the development of hypertension in salt-dependent hypertension, and this augmentation may be mediated by sympathetic stimulation independent of salt retention.

Analysis of Variance↗
PubMed1993

Depressor effect of intraventricular administration of calcium on spontaneously hypertensive rats.

The role of central Ca2+ in the regulation of blood pressure (BP) was investigated in conscious spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY). Ten microliters of a high Ca2+ solution (Ca2+: 32.6 mM) administered intracerebroventricularly (i.c.v.) decreased the mean arterial pressure (MAP) for more than 20 min in SHR (n = 7, P < 0.005), while no change of MAP was observed in the WKY (n = 6). This depressor response to Ca2+ i.c.v. was dose-dependent at Ca2+ concentrations between 16.3 and 65.2 mM. We also investigated the effect of high Ca2+ i.c.v. in SHR after pretreatment with Ca2+ channel blockers, diltiazem (60 micrograms/10 microliters) or nisoldipine (4, 8, 16 and 32 micrograms/10 microliters), administered i.c.v., the autonomic ganglion blocker, hexamethonium (50 mg/kg), administered i.v. and alpha-methyl-p-tyrosine (100 and 400 micrograms/10 microliters) delivered i.c.v. Pretreatment with i.c.v. diltiazem (n = 8) or nisoldipine (n = 5 for 8 micrograms, n = 6 for 4, 16, 32 micrograms) abolished and/or blunted the decrease of MAP due to high Ca2+. Hexamethonium administered i.v. (n = 6) also canceled the depressor action of i.c.v. Ca2+. Pretreatment with 100 micrograms of i.c.v. alpha-methyl-p-tyrosine could not prevent the depressor action of i.c.v. Ca2+; however, 400 micrograms of alpha-methyl-p-tyrosine administered i.c.v. abolished the effect of i.c.v. Ca2+. Furthermore Ca2+ channel blockers administered i.c.v. in themselves increased MAP in SHR (P < 0.05). These results suggest that central Ca2+ is involved in the central regulation of BP in SHR. This effect may be mediated through changes in sympathetic activity.

Animals↗
PubMed1993

Impaired left ventricular filling in borderline hypertensive patients without cardiac structural changes.

To determine the effect of borderline hypertension on left ventricular diastolic performance, 16 patients with borderline hypertension who did not have left ventricular hypertrophy and 16 age-sex-matched patients with normotension of similar age and body mass index were investigated. Pulsed Doppler echocardiography was used to record left ventricular filling signals at rest and immediately after supine ergometer exercise. All subjects had normal left ventricular structure and systolic function. At rest the borderline hypertension group in comparison with the normotension group had a depressed peak velocity of early filling (E) (44 +/- 7 vs 54 +/- 10 cm/sec; p < 0.01), no enhanced peak velocity of late filling (A) (52 +/- 8 vs 50 +/- 11 cm/sec; not significant), and a reduced E/A ratio (0.9 +/- 0.2 vs 1.1 +/- 0.3; p < 0.05). Atrial filling time and preejection period were similar in the two groups. The effect of exercise on left ventricular filling velocity in patients with borderline hypertensive resembled that in those with normotension. Percentage changes in E (+14% +/- 12% vs +14% +/- 13%) and A (+13% +/- 8% vs 11% +/- 12%) were equivalent, suggesting a preserved diastolic reserve for exercise in the borderline hypertension group. In conclusion, borderline hypertension appears to be predictive of early filling impairment, and a late filling compensative mechanism is not yet apparent. These findings in borderline hypertension without apparent cardiac damage call for clinical attention to prevent further deterioration in cardiac function.

Adult↗
PubMed1993

Reversal of diastolic dysfunction in borderline hypertension by long-term medical treatment. Longitudinal evaluation by pulsed Doppler echocardiography.

This study aimed to assess the left ventricular diastolic function of borderline hypertensive patients (BHT) and to determine the effect of long-term blood pressure control by an angiotensin converting enzyme inhibitor on the left ventricular filling profile. Pulsed Doppler echocardiograms were obtained from 18 BHT (14 men, 4 women; mean age: 55 years) and 20 age-sex matched normotensive controls. Studies were done at rest and immediately after exercise on a supine ergometer bicycle. Of the 18 patients, 11 were treated with delapril (30 mg/day) and followed up with longitudinal studies for 24 weeks. At baseline, BHT had a normal left ventricular structure. They showed a decreased peak velocity of early filling (E) (43 +/- 7 v 56 +/- 13 cm/sec, P < .01) and E/A ratio (0.83 +/- 0.2 v 1.08 +/- 0.3, P < .01), whereas peak velocity of late filling (A) and deceleration time (Dec T) were similar in the two groups. Exercise-enhanced filling indices were observed in both groups. Following blood pressure control, no change was observed in the left ventricular morphology. In contrast, progressive improvement of resting and after exercise peak velocity of early filling and E/A ratio were achieved. This indicates that long-term angiotensin converting enzyme inhibition ameliorates cardiac function in borderline hypertension.

Adult↗
PubMed1993

Augmented central pressor action of magnesium in SHR.

This study attempted to determine whether central magnesium (Mg) influences the regulation of blood pressure (BP). An intracerebroventricular (icv) injection of a high Mg2+ solution (190.0 mEq/L, 10 microL), made by adding MgC12 to artificial cerebrospinal fluid, increased the mean BP in both conscious spontaneously hypertensive rats (SHR; n = 17, p < 0.001) and Wistar Kyoto rats (WKY; n = 8, p < 0.005). Spontaneously hypertensive rats showed a greater pressor response than WKY (+11.7 +/- 0.9 mm Hg versus +3.5 +/- 1.1 mm Hg, p < 0.001). This pressor response to Mg2+ given icv was dose-dependent in the range of Mg2+ concentration between 47.5 and 190.0 mEq/L in SHR. A high Mg2+ solution (190.0 mEq/L), made by adding MgSO4 given icv, also increased the mean BP in SHR (n = 7, p < 0.001) and WKY (n = 6, p < 0.01), whereas the high osmolarity solution (340 mOsm/kg H2O) given icv did not change the mean BP in either SHR or WKY. Also administered was a high Mg2+ solution icv after either hexamethonium bromide (Hx; 50 mg/kg intravenously) or arginine vasopressin antagonist (aAVP, (CH2)5Tyr(Me)AVP, 30 micrograms/kg i.v.). The pressor response to the high Mg2+ solution was abolished by arginine vasopressin antagonist both in SHR and WKY, although it was not canceled by Hx. A high Mg2+ solution administered icv caused a 3.5-fold increase in plasma arginine vasopressin concentration in SHR (n = 5, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Contribution of the central interaction between calcium and sodium to hemodynamic regulation in spontaneously hypertensive rats.

The contribution of the central interaction between calcium and sodium to hemodynamic regulation was assessed in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats. The effect of a high calcium solution (Ca2+, 130 mg/dl, 10 microliters) infused into the cerebral ventricle (i.c.v.) on hemodynamic responses induced by a high sodium solution (Na+, 1,000 mEq/1, 10 microliters) i.c.v. and the mechanism by which high Ca2+ affects the hemodynamic responses induced by high Na+ i.c.v. were studied. High Na+ i.c.v. induced a pressor response with tachycardia in the SHRs, but induced a pressor response with reflex bradycardia in the WKYs. Prior treatment with high Ca2+ i.c.v. attenuated the pressor response induced by high Na+ i.c.v. (+55.6 +/- 4.4 to +33.1 +/- 3.2 mmHg, P < 0.01) and restored reflex bradycardia (+86.4 +/- 7.7 to -26.7 +/- 7.6 bpm, P < 0.01) in SHRs. Whereas prior treatment with high Ca2+ i.c.v. attenuated the pressor response (+35.7 +/- 2.0 to +22.2 +/- 4.0 mmHg, P < 0.05), it did not alter the degree of reflex bradycardia (-81.7 +/- 7.1 to -69.2 +/- 120 bpm, n.s.) in WKYs. Ganglionic blockade attenuated the pressor response (+56.9 +/- 3.5 to +42.9 +/- 2.3 mmHg, P < 0.05) and restored reflex bradycardia (+82.1 +/- 10.3 to -65.9 +/- 11.0 bpm, P < 0.01) in SHRs, whereas, inhibition of arginine vasopressin attenuated the pressor response without modification of the tachycardic response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Increase in water permeability of negatively charged liposomal membrane by local anesthetics.

Effect of the local anesthetics dibucaine, tetracaine, lidocaine and procaine on the water permeability of phospholipid membrane was examined using liposomes composed of bovine heart cardiolipin and egg yolk phosphatidylcholine in a molar ratio of 2/98 by monitoring the osmotic shrinkage of liposomes in hypertonic glucose solution at pH 7.3 and 30 degrees C. These local anesthetics greatly accelerated the water permeability by destabilizing the membrane structure. The effect was found to be governed by the hydrophobicity of the anesthetics. There was also a significant correlation between the membrane destabilizing actions and the anesthetic activities.

Anesthetics, Local↗
PubMed1992

The influence of advancing age on the electrophysiological changes of the atrial muscle induced by programmed atrial stimulation.

The influence of advancing age on the electrophysiological changes of the atrial muscle induced by programmed atrial stimulation, such as fragmented atrial activity (FAA), interatrial conduction delay (ICD), and repetitive atrial firing (RAF), was investigated in 42 patients with neither documented episodes of paroxysmal atrial fibrillation nor sick sinus syndrome. The induction rates of FAA, ICD, and RAF were not affected by age. The zones of FAA, ICD and RAF, did not show any correlation with age. However, the longest coupling interval giving rise to FAA (longest CI-FAA) or ICD (longest CI-ICD) showed a significant correlation with age (longest CI-FAA; r = 0.428, p less than 0.01, longest CI-ICD; r = 0.398, p less than 0.01). Although the longest coupling interval giving rise to RAF did not show a direct correlation with age (r = 0.267), it was significantly longer in patients over 60 years of age than in those under 60 (p less than 0.05). These results suggest that aging affects the electrophysiological properties of the atrial muscle, which can help to explain why atrial fibrillation is seem more frequently in the elderly.

Adult↗
PubMed1991

Changes in sodium-22 turnover and total body potassium in two-kidney, one-clip renovascular hypertension.

Changes in sodium-22 turnover and total body potassium (TBK) were studied during acute (within 2 weeks after clipping) and chronic (12-14 weeks after clipping) phases in two-kidney, one-clip (2k, 1c) hypertensive rabbits by using a whole body counter. Sodium-22 injected intravenously was eliminated more rapidly in hypertensive rabbits than in controls. The biological half-life (BHL) of sodium-22 was shorter in hypertensive rabbits during both acute (p less than 0.05) and chronic phases (p less than 0.001). A significant negative correlation was obtained between the BHL of sodium-22 and blood pressure (r = -0.588, p less than 0.05) in hypertensive rabbits. TBK decreased significantly at the chronic phase in hypertensive rabbits (p less than 0.05), while TBK showed no significant change in controls. Serum sodium and potassium did not change during the observation period. Increased plasma aldosterone concentration was observed during the acute phase in hypertensive rabbits. These results suggested that sodium retention was not a major factor in the acute and chronic phases of 2k, 1c hypertension in rabbits and that pressure natriuresis could explain, at least in part, the lack of sodium retention. Furthermore, there appears to be a derangement in the intracellular potassium metabolism which may be associated with the maintenance rather than the development of hypertension.

Aldosterone↗