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Biomedical subjects

H Seo

Publications and source records attributed to H Seo.

At least 145 records · Page 8Linked to original sources
PubMed1995

Exercise capacity in hypertrophic cardiomyopathy. Role of stroke volume limitation, heart rate, and diastolic filling characteristics.

BACKGROUND: We previously showed that exercise capacity in patients with hypertrophic cardiomyopathy (HCM) is related to peak exercise cardiac output. Cardiac output augmentation during exercise is normally dependent on heart rate (HR) response and stroke volume (SV) augmentation by increased left ventricular end-diastolic volume and/or increased contractility. We hypothesized that in contrast to normal subjects, peak exercise capacity in patients with HCM is determined by the diastolic filling characteristics of the left ventricle during exercise, which would in turn determine the degree to which SV is augmented, and that HR is a relatively unimportant determinant of peak exercise capacity. METHODS AND RESULTS: Twenty-three patients with HCM underwent invasive hemodynamic evaluation and measurement of maximal oxygen consumption (VO2max) during erect treadmill exercise to assess the relative importance of changes in HR and SV in determining exercise capacity. Hemodynamic responses to erect and supine exercise were compared in 10 of these patients. In a separate group of 46 patients with HCM, the relation between VO2max and exercise diastolic filling indexes was assessed. Peak HR during erect exercise was 92 +/- 8% of predicted maximum. VO2max was 29.0 +/- 6.4 mL.kg-1.min-1 and was related significantly to peak exercise cardiac index and SV index (r = .71, P < .001 and r = .66, P = .001, respectively) but not to peak HR, HR deficit, or resting or peak pulmonary capillary wedge pressure. Peak cardiac output during erect exercise was not related to peak HR (r = .13, P = NS). When erect and supine exercise were compared, peak HR was lower in the supine position (153.3 +/- 19.9 beats per minute supine versus 172.0 +/- 17.6 beats per minute erect, P = .003), but peak exercise cardiac index was similar (7.9 +/- 2.6 L.min-1.m-2 supine versus 7.5 +/- 2.8 L.min-1.m-2 erect). Pulmonary capillary wedge pressure was higher at rest in the supine versus erect position (15.3 +/- 5.2 versus 8.1 +/- 6.1 mm Hg) but was not significantly higher at peak exercise in the supine versus erect position (28.5 +/- 8 versus 22.4 +/- 11.6 mm Hg erect, P = NS). In the separate group of 46 patients with HCM, VO2max was significantly inversely related to time to peak filling at peak exercise (r = -.60, P < .0001) but did not correlate with time to peak filling at rest, resting ejection fraction, peak filling rate, or peak exercise peak filling rate. CONCLUSIONS: SV is the major determinant of peak exercise capacity in the erect position in patients with hypertrophic cardiomyopathy. This in turn is determined by the exercise left ventricular diastolic filling characteristics. HR augmentation does not appear to be a major determinant of peak cardiac output in the erect position.

Adult↗
PubMed1995

A keratan sulfate proteoglycan marks the boundaries in the cortical barrel fields of the adult rat.

The present study uses the monoclonal antibody TED 15 to examine the distribution of a keratan sulfate proteoglycan, ABAKAN, in the barrel field of the rat somatosensory cortex. At birth there is very little ABAKAN present in the somatosensory cortex. The levels of this proteoglycan increase during development until the highest levels are reached in the adult rat. Immunohistochemistry reveals that the TED 15 immunoreaction product marks the boundaries between cortical barrels. At postnatal day 7 (P7) the proteoglycan is localized specifically to the boundary regions. As the brain matures, the levels of ABAKAN increase in the barrel hollows and in the surrounding cortex; however the boundary regions maintain a higher level of expression even in the adult animal. The high levels of ABAKAN observed in the adult barrel fields indicate that unlike other boundary molecules this proteoglycan may be involved in maintaining the structure of the adult somatosensory cortex.

Animals↗
PubMed1995

Effect of aphidicolin on DNA synthesis in cultured human thyroid cells.

To investigate whether partial inhibition of DNA synthesis affects the growth of thyroid cells, human thyroid cells were cultured in the presence of aphidicolin for 24h. After removal of aphidicolin, the growth of thyroid cells was evaluated by [3H] thymidine uptake and analysis of cell cycle by flow cytometry. In Graves' thyroid cells, [3H] thymidine uptake and the percentage of cells in S+G2/M phase increased during 24 hours after washout of aphidicolin, whereas those were not augmented in normal thyroid cells. Thus, the acceleration of DNA synthesis occurred after the partial inhibition of it by aphidicolin in Graves' thyroid cells, but not in the normal thyroid cells. This phenomenon might, at least in part, explain the difference of growth regulation between Graves' and normal thyroid cells.

Aphidicolin↗
PubMed1995

Familial dilated cardiomyopathy in the United Kingdom.

OBJECTIVES: To determine the frequency and mode of inheritance of familial dilated cardiomyopathy in the United Kingdom. BACKGROUND: Two recent prospective studies have suggested that familial forms of dilated cardiomyopathy are common but have been limited by selective screening methods, inadequate diagnostic criteria, and low rates of ascertainment. METHODS: Prospective screening study of 236 relatives from 40 families of patients with dilated cardiomyopathy. Screening consisted of clinical examination, 12 lead electrocardiogram, and two-dimensional Doppler echocardiography. Relatives with systemic hypertension and other cardiac diseases were excluded from the study. All echocardiograms were performed by an experienced echocardiographer who was blinded to clinical information. Relatives were classified as having dilated cardiomyopathy, left ventricular enlargement (method of Henry), depressed fractional shortening, or as being normal. Relatives with abnormal investigations underwent further evaluation as appropriate. RESULTS: Twenty five cases of dilated cardiomyopathy were identified and came from 10 (25%) of the 40 families screened. Pedigree analysis was most consistent with autosomal dominant inheritance and variable penetrance (65-95%). Of the remaining apparently healthy relatives, 37 (18%) were found to have left ventricular enlargement and nine (4%) depressed fractional shortening; these values were significantly higher than those observed in 239 healthy controls (24 (10%), P = 0.02 and one (0.4%), P = 0.01, respectively). CONCLUSIONS: Patients with dilated cardiomyopathy commonly have an affected family member and a high proportion of apparently healthy relatives with minor echocardiographic abnormalities. Segregation analysis suggests that familial dilated cardiomyopathy is the result of the transmission of a rare autosomal dominant gene. Further studies are currently underway to characterise the molecular basis of familial dilated cardiomyopathy and identify early disease within these families.

Adolescent↗
PubMed1995

Factor(s) present in sera from patients on long-term hemodialysis increase(s) mRNAs for collagenase and stromelysin in synovial cells.

Rheumatic disorders are common complications in patients on long-term hemodialysis (HD), and abnormalities of collagen metabolism in the musculoskeletal system have been suggested in these patients. Since collagenase, which catalyzes the initial step in the proteolytic degradation of collagen, plays an important role in the metabolism of collagen, the present study investigated whether factor(s) present in the sera from patients on long-term HD stimulates collagenase gene expression in synovial cells. The addition of sera from 8 patients on long-term HD resulted in 1.5- to 4.0-fold increases in the collagenase mRNA level in human synovial cells as compared with that of sera from normal subjects. The collagenase-inducing factor(s) in uremic sera is more than 3,000 D in molecular mass and shows no binding to heparin. Uremic sera also increased stromelysin mRNA, but failed to exert any effect on mRNAs for tissue inhibitor of metalloproteinases and pro alpha 1(I)collagen. Our findings suggest that there exists a factor(s) to enhance degradation of synovial collagen in sera from long-term HD patients.

Cells, Cultured↗
PubMed1995

Interleukin 8 and biocompatibility of dialysis membranes.

To determine whether interleukin 8 (IL-8) can be used as an index of biocompatibility of dialysis membranes, the effects of hemodialysis (HD) on plasma IL-8 levels and the expression of IL-8 mRNA in peripheral blood mononuclear cell (PBMC) were compared among regenerated cellulose (RC), polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) dialyzers. HD using RC dialysers significantly increased plasma IL-8 levels and induced abundant expression of IL-8 mRNA in PBMC. HD using PMMA dialyzers also increased plasma IL-8 levels and induced slight expression of IL-8 mRNA. In contrast, HD using PAN dialyzers neither increased plasma IL-8 levels nor induced the expression of IL-8 mRNA. In vitro studies demonstrated that IL-8 was considerably adsorbed by PAN membranes and not at all by RC and PMMA. These studies indicate that plasma IL-8 level and expression of PBMC IL-8 mRNA can be used as indices of biocompatibility of dialysis membranes.

Acrylic Resins↗
PubMed1995

Determinants of exercise capacity in the hypertensive elderly--a study based on the assessment of cardiac reserve by dipyridamole radionuclide angiography.

To evaluate the determinants of exercise capacity in the hypertensive elderly with an assessment of cardiac reserve by dipyridamole radionuclide angiography, 31 elderly subjects (aged 62 to 78 years, 15 hypertensive and 16 normotensive) underwent symptom-limited maximum treadmill exercise with measurement of maximal oxygen consumption along with radionuclide angiography in list mode at rest and after dipyridamole infusion. In the normotensive elderly, maximal oxygen consumption correlated with relative filling volume during the rapid filling period at rest (r = 0.58; p < 0.05), and correlated inversely with the percent change in the peak ejection rate with dipyridamole (r = -0.63; p < 0.01). In contrast, maximal oxygen consumption correlated with atrial contribution at rest (r = 0.69; p < 0.005), and correlated inversely with the percent change in atrial contribution with dipyridamole (r = -0.87; p < 0.0001) in the hypertensive elderly. These results indicate that the mechanisms for maintaining exercise capacity are different in elderly subjects with or without hypertension.

Aged↗
PubMed1995

Adrenocorticotropic hormone (ACTH) increases the expression of its own receptor gene.

Regulation of the ACTH receptor (R) in the adrenal gland by its own ligand "ACTH" has been a matter of controversy. In the present study, whether ACTH regulates the expression of mRNA for its own receptor in the adrenal gland was studied in human subjects and in rats in vivo. In the human study, adrenal adenoma tissues as well as adjacent normal tissues were obtained at surgery from two patients with typical Cushing's syndrome. Northern blot analysis revealed two ACTH-R mRNA species with 4.0 kb and 2.0 kb. ACTH-R mRNAs in the adenoma tissues were much more abundant than those in the normal tissues from the two patients, suggesting that the mRNA in normal adrenal tissue is either suppressed by cortisol excess or the absence of ACTH. To examine the mechanism involved in ACTH-R mRNA regulation, the changes in the receptor mRNA caused by ACTH were studied in dexamethasone-treated rats. Administration of dexamethasone for 5 days resulted in a marked decrease in ACTH-R mRNA to an undetectable level. A bolus administration of ACTH1-24 intravenously or ACTH-Z1-24 intramuscularly to the dexamethasone-treated rat did not cause any significant change in ACTH-R mRNA from 0.5 to 12 h after the administration. However, a significant increase in the receptor mRNA was observed at 24 h after the ACTH-Z1-24 and the level was further increased until 48 h followed by a sustained increase at 72 h when it was given once every 24 h. These data suggest that the ACTH-receptor is increased by ACTH at a pretranslational level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1995

Changes in the markers of bone metabolism following skeletal unloading.

To elucidate the mechanism in disuse bone atrophy induced by skeletal unloading, we studied the indices of bone resorption and bone formation in the femur of tail-suspended rats. The duration of the suspension ranged from 1 to 14 days. Tartrate-resistant acid phosphatase mRNA, an index used to evaluate bone resorption, increased significantly more than the controls for the first 3 days of the tail-suspension experiments, compared those in controls. Osteocalcin and alkaline phosphatase, two common markers for bone formation, were also monitored. Osteocalcin mRNA started to decrease after 3 days of suspension. Five days later, alkaline phosphatase mRNA showed a decrease. Levels of both of these mRNAs remained low for the remaining suspension period. Sequential changes in the markers for bone metabolism indicate that the transient increase in bone resorption preceded the decrease in bone formation in the development of disuse bone atrophy induced by skeletal unloading.

Acid Phosphatase↗
PubMed1995

Catecholamine response to stress: age related modifications in tail-suspended rats.

The catecholamine response to acute stress has been shown to change with age. However, alterations under chronic stress conditions have not been established. This study attempted to determine whether aging modifies the catecholamine response to chronic stress load in rats subjected to tail suspension. Urinary excretions of epinephrine (E) and norepinephrine (NE) were monitored before and during the tail suspension experiments in rats at two different ages: 5 weeks old (young) and 18 months old (aged). Basal excretions of E and NE before the suspension were higher in the aged rats, indicating that sympathetic-adrenal medullary activities increase with age under resting conditions. The chronic stress load elicited E responses in the aged rats similar to those in the young rats. The NE responses, however, were completely different in that tail suspension caused a greater increase in NE excretion in the young rats than in the aged rats. This finding suggests that the sympathetic response to chronic stress load changes with age.

Adrenal Glands↗
PubMed1995

Effects of stress on Kv1.5 K+ channel gene expression in the left ventricle of rat hearts.

Voltage-dependent K+ channels contribute to the repolarization phase of the cardiac action potential. An increase in Kv1.5 K+ channel gene expression by a pharmacological dose of glucocorticoid was reported recently in the heart of an adrenalectomized rat. In this study, we examined whether physiological elevations of glucocorticoid induced by tail suspension affects the K+ channel gene expression. Five-week-old male Wistar rats were subjected to tail suspension for three days. Total RNA was extracted from the ventricle, and the level of Kv1.5 mRNA was determined by Northern blot analysis. On the first day, the Kv1.5 mRNA had increased over the non-suspended rat. By the third day, mRNA had increased significantly by more than 3-fold. knowing that urinary excretions of glucocorticoid increase in tail-suspended rats, these findings suggest that physiologically elevated glucocorticoid may upregulate Kv1.5 K+ gene expression.

Action Potentials↗
PubMed1995

[Diagnosis and prognosis of elderly patients with coronary artery disease: assessment with dipyridamole thallium imaging].

Noninvasive evaluation of coronary artery disease is difficult in elderly patients because of their limited exercise-capacity. The diagnostic and prognostic value of dipyridamole perfusion scintigraphy was assessed in 147 patients aged 65 years and older. All patients underwent coronary angiography. Initially, 32 patients had percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). The other 115 patients were first treated medically and followed for a mean of 29 +/- 22 months. Nine patients (7.9%) had cardiac events including cardiac death and coronary intervention (PTCA or CABG) during the follow-up. Dipyridamole perfusion scintigraphy was performed safely in all patients, whereas treadmill exercise testing could not be adequately performed in 24 patients, 18 of whom had multivessel disease. Multiple regression analysis showed that: fixed defect and reversible defect were powerful detectors of coronary lesions (p = 0.0001, p = 0.0027, respectively), all patients with fixed disease and 94% of patients with only reversible defect had significant coronary lesion; Diffuse slow washout and ST depression were statistically significant for detecting multivessel coronary lesions in patients with fixed disease (p = 0.0001, p = 0.017, respectively), the sensitivity and specificity of diffuse slow washout and/or ST depression for detecting multivessel coronary lesions ware 85% and 74%, respectively, and ST depression was statistically significant for detecting multivessel coronary lesions (p = 0.0002) in patients with only reversible defect, the sensitivity and specificity of ST depression were 88% and 64%, respectively. Cox survival analysis identified diffuse slow washout as the best predictor of future cardiac events among the scintigraphic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

Sensitivity of osteoinductive activity of demineralized and defatted rat femur to temperature and duration of heating.

For autogenous and allogeneic bone grafts, heat treatment has been thought to kill malignant cells and viruses such as human immunodeficiency virus. It is unclear whether heat treatment could preserve bone-inductive activity. Cortical bones from 6-week-old rat femurs were heated in a water bath at a temperature of 50 degrees-100 degrees C for periods of 15 minutes to 10 hours. After treatment, they were defatted and decalcified. Each sample was transplanted into the hamstring muscle of 3-week-old rats. Eleven days after transplantation, the samples were removed and messenger ribonucleic acids (mRNAs) were determined for alkaline phosphatase and collagens in the transplant. Twenty-one days after transplantation, actual bone formation was studied by histologic analysis and measurement of calcium content. Heat treatment at 60 degrees C for 10 hours and at 70 degrees C for 1 hour preserved bone-inductive activity, as indicated by the induction of mRNAs for alkaline phosphatase and Type I and Type II collagens. Significant decreased in Type II collagen mRNA and calcium content were observed at 70 degrees C when the transplants were heated for 10 hours, suggesting the importance of evaluating the duration of heat treatment.

Alkaline Phosphatase↗
PubMed1995

[Significance of silent ischemia in dipyridamole perfusion scintigraphy: evaluation in patients with angina].

The significance of silent myocardial ischemia detected by dipyridamole perfusion scintigraphy was evaluated in 80 patients with stable angina and reversible defects (RD) but no infarction. The patients were divided into two groups: 26 patients with silent RD (62 +/- 7 years) and 54 patients with painful RD (65 +/- 7 years). Coronary risk factors, extent of coronary lesions, localization and degree of RD, and prognosis were compared. There was no significant difference in the incidence of coronary risk factors between these two groups, except for hyperlipidemia which was less frequently observed in patients with silent RD than in those with painful RD (8% vs 41%, p < 0.01). Coronary angiography revealed a higher prevalence of insignificant lesions or single vessel disease in patients with silent RD than in those with painful RD (73% vs 39%, p < 0.05). Dipyridamole perfusion scintigraphy revealed a lower degree of RD in patients with silent RD than in those with painful RD (4.4 +/- 3.3 vs 9.0 +/- 4.1 segments, p < 0.05), though there was no significant difference in the localization of RD between these two groups. Treadmill stress testing revealed a lower incidence of chest pain in patients with silent RD than in those with painful RD (26% vs 65%, p < 0.05), despite the mean exercise-duration being significantly longer in the former than in the latter (5.5 +/- 1.7 vs 3.9 +/- 1.7 min, p < 0.05). There was no significant correlation between the late peak serum ML-1 level and LV volume, and the size and motion of infarcted areas in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[Prognosis of patients with triple vessel disease and old myocardial infarction: relationship to the number of total coronary occlusions].

Patients with myocardial infarction (MI) and triple vessel coronary disease generally have poor prognoses. However, it is not known whether there are particular angiographic variables associated with the poor prognosis in MI patients with triple vessel disease. The angiographic variables for poor prognosis were investigated in 43 MI patients with triple vessel disease (32 men and 11 women, mean age 63 +/- 9 years) who were followed medically for a mean of 32 +/- 28 months. There were 13 cardiac deaths (30%) and 10 late-coronary artery bypass grafting (23%). Twenty patients were alive and well. The patients who died of cardiac causes had lower ejection fractions (42 +/- 18% vs 49 +/- 15%, p < 0.05), a higher prevalence of two vessel occlusion (77% vs 40%, p < 0.05), and a higher prevalence of coronary occlusion opposite the MI site (69% vs 25%, p < 0.01) when compared to survivors, although there were no significant differences in age, MI sites, or the prevalence of occlusion in the infarct-related artery. Multivariate analysis with the Cox proportional hazards model revealed that coronary occlusion opposite the MI site (hazards ratio 16.36) and an age of > or = 65 years (4.46) indicated a significantly high ratio. The hazard ratio of the ejection fraction and two vessel coronary occlusion were not significant. The poor prognosis of MI patients with triple vessel coronary disease may be related to impaired left ventricular function and to coronary occlusion opposite the MI site and greater age. This may have important clinical implications in the initial decision for interventional therapy.

Adult↗
PubMed1994

[Results of radiotherapy for stage III uterine cervical carcinomas and preliminary study of combined radiotherapy and transarterial infusion chemotherapy].

This is a retrospective analysis of 55 patients with stage III carcinoma of the uterine cervix treated with radiation from November 1984 through December 1991. Eleven of the patients were treated with radiation and transarterial infusion chemotherapy (TAI), using cis-platinum and pepleomycin. The 3- and 5-year cumulative survival rates for all patients were 61% and 58%, respectively, and the 3-year cumulative survival rate for the group with combined radiation and TAI was 47%. According to initial failure site, the locoregional recurrence rate was 36.8%, and that for para-aortic lymph node metastasis and distant metastasis was 31.6%. The failure pattern was similar between the irradiation only group and the group with combined radiation and TAI. The incidence of intestinal complications of grades 1 and 2 was 20%. Irradiation combined with TAI did not increase the incidence of complications.

Adult↗