Biomedical subjects

H Seo

Publications and source records attributed to H Seo.

At least 19 recordsLinked to original sources

PubMed1992

Value of dipyridamole thallium-201 imaging in noninvasive differentiation of idiopathic dilated cardiomyopathy from coronary artery disease with left ventricular dysfunction.

The purpose of this study was to noninvasively differentiate in patients with reduced global left ventricular function between those with idiopathic dilated cardiomyopathy (IDC) and coronary artery disease (CAD). Clinical features and findings of dipyridamole thallium-201 imaging in 55 consecutive patients with IDC were compared with those in 77 with CAD. Left ventricular ejection fraction was similar between the 2 groups (34 +/- 16% vs 39 +/- 7%). Patients with IDC had lower incidences of ischemic chest pain (11 vs 79%; p less than 0.0001), electrocardiographic evidence of myocardial infarction (24 vs 82%; p less than 0.0001), and reversible defects (4 vs 57%; p less than 0.0001) than did those with CAD. The lowest percent thallium uptake in the initial imaging was less with CAD than IDC (30 +/- 15% vs 59 +/- 10%; p less than 0.001). Patterns of perfusion defects were classified as: no defects, multiple small defects and large defects. Of patients with IDC, 15 had no defects, 19 had multiple small defects, and 21 had large defects, whereas all those with CAD had large defects (p less than 0.0001). Stepwise discriminant analysis, using chest pain and electrocardiography, revealed sensitivity of 89%, specificity of 87%, accuracy of 88%, and positive predictive value of 83% in the identification of patients with IDC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Modification of water and electrolyte metabolism during head-down tilting by hypoglycemia in men.

The effect of hypoglycemic stress on the changes in water and electrolyte metabolism induced by head-down tilting (HDT) was studied. Six healthy men were subjected to postural changes (30 min standing, 2 h HDT, 1 h standing), with or without the intravenous administration of insulin at the beginning of HDT. When insulin was not given, antidiuretic hormone (ADH), cortisol, plasma renin activity (PRA), aldosterone, and catecholamine levels were decreased and atrial natriuretic polypeptide (ANP) levels increased during HDT. These changes were associated with 2.5- and 1.5-fold increases in urine flow and sodium excretion, respectively, when compared with the amounts before HDT. On the other hand, insulin-induced hypoglycemia during HDT produced increases in ADH, cortisol, PRA, aldosterone, and catecholamine levels. At the same time, an exaggerated ANP response by HDT was observed. These hormonal changes were associated with an abolishment of the increases in urine flow and sodium excretion. It is suggested that acute stress modifies the changes in fluid and electrolyte metabolism induced by HDT.

Adult↗

PubMed1992

The effect of thyroid hormone on fibronectin messenger ribonucleic acid levels in primary cultured rat hepatocytes.

Our previous in vivo studies demonstrated that thyroid hormone promotes the expression of the fibronectin (FN) gene in the rat liver, while it inhibits the synthesis in cultured human skin fibroblasts. These results can be interpreted as either different regulation of FN synthesis or gene expression among tissues, or divergent results of experiments performed in vivo or in vitro. Here we report on the action of thyroid hormone on FN gene expression in vitro using primary cultured hepatocytes compared to that in cultured skin fibroblasts. Hepatocytes were isolated from hypothyroid rats and were cultured in medium supplemented with thyroidectomized bovine serum (TxBS) or fetal bovine serum (FBS). T3 was added 2 or 24 h after plating, and cells were harvested after 2, 6, or 24 h. Total RNA was extracted, and mRNAs for rat FN and albumin were measured. The requirement of de novo protein synthesis for thyroid hormone-mediated induction of FN mRNA was examined by the addition of cycloheximide 15 min before T3 addition. The amount of FN mRNA significantly decreased in the hepatocytes cultured with TxBS compared with those cultured with FBS. The addition of T3 to TxBS resulted in the restoration of FN mRNA to the level in hepatocytes cultured in FBS. FN mRNA increased during the course of culture in the absence of T3; however, a further increase was observed 6 h after T3 addition. The abundance of albumin RNA decreased during the course of culture, but unlike FN mRNA, it was not changed by T3 addition. The increase in FN mRNA by T3 was not influenced by cycloheximide. These results indicate that thyroid hormone enhances FN gene expression in hepatocytes by its direct action without requiring de novo protein synthesis. In contrast, T3 decreased FN mRNA in cultured skin fibroblasts. Thus, the mode of thyroid hormone action on FN gene expression is different among tissues.

Animals↗

PubMed1992

A 3',5'-cyclic adenosine monophosphate-dependent pathway is responsible for a rapid increase in c-fos messenger ribonucleic acid by adrenocorticotropin.

ACTH rapidly and transiently increases c-fos mRNA in the rat adrenals in vivo. The present investigation was undertaken in order to determine what kind(s) of second messenger systems is involved in this increase. Rat adrenal cells were grown in monolayers in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum. After 2 days of culture, cells were treated with ACTH and various agents alone or in combination. The amount of c-fos mRNA was determined by dot blot hybridization and corticosterone levels in the media were measured by RIA. ACTH (300 pg/ml) increased c-fos mRNA transiently with a peak level after 60 min. A similar increase was observed when (Bu)2cAMP (1 mM) was substituted for ACTH. Pretreatment with N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide (H-89), a selective inhibitor of cAMP-dependent protein kinase, suppressed both basal and ACTH-increased c-fos mRNA. H-89 also suppressed corticosterone production. On the other hand, neither 12-O-tetradecanoyl-phorbol-13-acetate (100 ng/ml) nor elevated potassium ion (50 mM) affected the amount of c-fos mRNA and corticosterone production. Furthermore, pretreatment with cycloheximide (5 micrograms/ml) increased both basal and ACTH-increased c-fos mRNA. These results indicate that ACTH increases c-fos mRNA by phosphorylation of preexisting trans-acting factor(s) via cAMP-dependent protein kinase in common with steroidogenesis.

Adrenal Glands↗

PubMed1992

An additional carbohydrate chain in the variant thyroxine-binding globulin-Gary (TBGAsn-96) impairs its secretion.

The T4-binding globulin-Gary (TBG-G) variant has severely impaired T4 binding, is unstable at 37 C, and presents an apparent anodal shift of all isoforms when submitted to isoelectric focusing. Inheritance of this abnormal TBG produces a profound decrease in the serum levels of native TBG with reciprocal changes in its denatured form, causing thyroid hormone concentrations to be as low as those found in complete TBG deficiency. The TBG-G gene possesses a single nucleotide substitution replacing the normal IIe96 (ATC) with Asn (AAC), thus creating a new site for N-linked glycosylation. In order to determine whether TBG-G contains an additional carbohydrate chain as indirectly suggested by the isoelectric focusing results, cDNAs containing the normal TBG (TBG-N), and TBG-G were inserted in the appropriate vectors to allow their expression in mammalian cells (COS-1) and in amphibian (Xenopus) oocytes. In both systems, expression of TBG-G yielded a larger molecule than TBG-N when analyzed by polyacrylamide gel electrophoresis under denaturing conditions. However, both were identical in size when synthesized in COS-1 cells in the presence of tunicamycin or when deglycosylated after their synthesis in Xenopus oocytes. Pulse chase experiments revealed impaired secretion and excessive overall intracellular degradation of TBG-G relative to TBG-N. As expected from studies on serum from affected subjects, in vitro expressed TBG-G had a 10-fold lower affinity for T4. These studies prove that the new site for potential glycosylation created by the point mutation in TBG-G is indeed glycosylated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Negative washout rate of myocardial thallium-201--a specific marker for high grade coronary artery narrowing.

A decline is usually observed in the myocardial uptake of thallium-201 in delayed imaging compared with initial imaging. In patients with severe coronary artery disease (CAD), the uptake is sometimes higher in the delayed than in the initial imaging, which is expressed as negative washout rate. To evaluate the diagnostic implications of this negative washout rate the findings of dipyridamole thallium scintigraphy in 582 patients with coronary artery disease were evaluated. The negative washout rate was present in 201 of 582 patients (35%). It had a significant association with high grade coronary artery narrowing of > or = 90%. Sensitivity in detecting patients with this high grade narrowing by negative washout rate was 48%, its specificity was 93%, and its positive predictive value was 94%. Sensitivity to detect individual coronary artery narrowing of > or = 90% did not decrease according to the extent of CAD, with the highest detection in the left anterior descending coronary artery and the lowest in the left circumflex coronary artery. Since patients with high grade coronary narrowing often require coronary intervention, the results of this study suggest the diagnostic importance of negative washout rate in the identification of the particular subset of patients with CAD.

Adult↗

PubMed1992

ACTH increases expression of c-fos, c-jun and beta-actin genes in the dexamethasone-treated rat adrenals.

Our recent finding that ACTH increases c-fos mRNA in the adrenal gland of hypophysectomized rats indicates that the gene product FOS may play an important role(s) in mediating the action of ACTH. However, hypophysectomy employed in that study causes the disappearance of trophic hormones other than ACTH and may modify the effect of ACTH. Thus, in the present investigation, dexamethasone-treated rats were used. Since FOS functions only when it dimerizes with JUN (the product of c-jun gene), the changes in the levels of c-fos and c-jun mRNAs were studied together with that of beta-actin mRNA which is also affected by ACTH. Northern blot analysis was employed to determine the mRNA levels. It was demonstrated that ACTH increases the mRNAs coding c-fos and c-jun in the adrenal glands of dexamethasone-treated, ACTH-suppressed rats. The c-fos mRNA was not detectable before ACTH administration. After ACTH administration, the mRNA levels were transiently increased, the maximum level being observed at 30 min after ACTH. At 180 min post ACTH, the level returned to the unstimulated level. The mRNA coding c-jun was detectable before ACTH administration and it also increased rapidly after ACTH with maximal stimulation at 30 min. However, the mRNA level at 180 min post ACTH was still higher than the unstimulated level. The changes in beta-actin mRNA were approximately the same as those of c-jun mRNA. These results suggest that increased expression of c-fos, c-jun and beta-actin genes by ACTH may play an important role in mediating its action on the adrenals.

Actins↗

PubMed1992

Gonadotropin induces expression of c-fos and c-jun genes in rat ovaries.

It has been shown that the expression of protooncogenes, c-fos and c-jun, induced by growth factors and hormones plays important roles in cellular proliferation, tissue differentiation and transcription of certain genes. Since gonadotropin stimulates ovarian steroidogenesis and cellular proliferation, we investigated whether gonadotropin affects the expression of c-fos and c-jun genes in rat ovaries. The expression of mRNA coding side chain cleavage enzyme (P450scc), the rate limiting enzyme in ovarian steroidogenesis was also studied. The effect of gonadotropin was examined in female rats whose gonadotrophs were medically ablated by GnRH agonist (TAP-144-SR). After intravenous administration of pregnant mare's serum gonadotropin (PMSG:30 IU/rat), their ovaries were dissected out at various time intervals and total RNA was extracted. Changes in the levels of c-fos, c-jun and P450scc mRNAs were determined by Northern blot analysis. The levels of c-fos and c-jun mRNAs increased rapidly and transiently with the peak levels at 15 min after PMSG administration. The levels of both mRNAs were decreased by 30 to 60 min. On the other hand, the levels of P450scc mRNA started to increase 60 min after PMSG. These results indicate that gonadotropin-induced increase in the expression of c-fos and c-jun genes may play important roles in mediating the action of gonadotropin on the ovaries.

Actins↗

PubMed1992

Source of prolactin in human follicular fluid.

To analyze whether prolactin (PRL) in human follicular fluid (FF) is synthesized locally or derived from the circulation, PRL concentrations of plasma and FF were determined in the patients after ovarian stimulations. The amounts of PRL messenger ribonucleic acid (mRNA) in the follicular tissues during different menstrual phases were also determined. The FF PRL concentration was correlated positively with plasma PRL and highest estradiol levels during the stimulatory cycle. No PRL mRNA sequence was detected in the RNAs extracted from follicles at any stage in the menstrual cycle, although beta-actin mRNA was detected in all samples. In a comparison with pituitary RNA, the PRL mRNA concentration in ovarian follicular tissues seemed to be 10,000 times less than that in the pituitary. These results suggest that FF PRL may not be synthesized locally, but derived from the pituitary via the circulation through passive diffusion, and thus regulated by estrogen.

Actins↗

PubMed1992

Tumor-specific binding of radiolabeled G-22 monoclonal antibody in glioma patients.

Iodine-131-labeled G-22 monoclonal antibody F(ab')2 fragment reaching specifically with a glioma-associated surface glycoprotein was administered to 12 glioma patients to investigate its use in radioimaging of intracranial gliomas. No immediate or delayed side effects were attributable to antibody injection. Nine patients received the radiolabeled complex intravenously. The images of low-grade gliomas were generally poor and disappeared within 4 days. High-contrast images were obtained beyond the 7th day in high-grade gliomas except one case in the pineal region. Three patients received intraventricular or intratumoral administration. Clear images of all tumors were demonstrated from the 2nd until later than the 7th day. One patient with cerebrospinal fluid (CSF) dissemination of brainstem glioma demonstrated negative CSF cytology after intraventricular administration.

Antibodies, Monoclonal↗

PubMed1992

[Prognosis of asymptomatic elderly patients with aortic stenosis].

To elucidate the prognosis of elderly patients with asymptomatic aortic stenosis (AS) and to assess the timing of aortic valve replacement (AVR), 21 asymptomatic patients (8 men, 13 women, mean age: 75 +/- 8 years (54-89 years)), who had Doppler echocardiographic evidence of a significant aortic pressure gradient of greater than 40 mmHg (mean gradient: 75 +/- 31 mmHg), were followed for 33 +/- 10 months. During the follow-up, there were 4 cardiac events (2 cardiac deaths, 2 late AVRs), and 2 non-cardiac deaths (cerebro-vascular accidents). Among 15 survivors, 13 patients were in NYHA class I--II, and the remaining 2 patients were found to have malignant disease. Compared to the 17 patients without cardiac events, those with cardiac events had significantly larger CTR (58 +/- 6% vs. 53 +/- 3%; p less than 0.01), although there were no significant difference in electrocardiographic LVH, echocardiographic LV mass, and Doppler pressure gradient between the two groups. The prevalence of the development of cardiac symptoms during the follow-up was not high (12%) in patients without cardiac events. Among 4 patients with cardiac events, one patient who was 89 years-old at diagnosis died of heart failure, one patient had fatal myocardial infarction which seemed to be unrelated to AS, and two patients had successful late AVR because of new heart failure. The low incidence of fatal cardiac events in asymptomatic patients with aortic stenosis and the relatively high possibility of developing non-cardiac events in elderly patients indicate that the decision-making for AVR should not be solely based upon the pressure gradient detected by Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Endocrinological evaluation of ACTH-secreting pituitary microadenomas: their location and alpha-melanocyte stimulating hormone immunoreactivity.

It has been hypothesized by Lamberts and coworkers in their analysis of 15 cases that adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas may be derived from either the anterior lobe or the intermediate lobe. The intermediate lobe type of Cushing's disease is thought to be controlled through a hypothalamic pathway and is characterized by hyperprolactinemia; suppressibility of cortisol with bromocriptine, and lower sensitivity to dexamethasone. The authors investigated the validity of this hypothesis in 125 cases of ACTH-secreting pituitary microadenomas by analyzing the endocrine findings, the locations of the microadenomas, and alpha-melanocyte stimulating hormone (alpha-MSH) immunoreactivity in the adenoma cells. No significant differences in the basal hormone levels, cortisol suppressibility with bromocriptine, sensitivity to dexamethasone, and recurrence rate were observed between patients with the microadenoma adjacent to the posterior lobe (considered typical of the intermediate lobe-derived tumor) or those with the microadenoma located in the anterior lobe. The locations of the microadenoma were not correlated with alpha-MSH immunoreactivity in the adenoma cells. No significant differences in endocrine findings were noticed between adenomas positive or negative for alpha-MSH. Thus, Cushing's disease cannot be simply divided into either the anterior lobe type or the intermediate lobe type by endocrinological evaluation as described by Lamberts, et al.

Adenoma↗

PubMed1992

[Correlation between clinical symptoms and draining pathways in dural arteriovenous malformation of the cavernous region].

The clinical picture of dural arteriovenous malformations cannot be explained on the basis of degree of arteriovenous shunting in many cases. In this study, therefore we focused on the relation between clinical symptoms and draining pathways. Eighteen patients with dural arteriovenous malformation in cavernous region were studied before treatment. All patients underwent examination for their clinical symptoms, opthalmological examination and angiography on admission. Angiograms were used to determine the degree of arteriovenous shunting and the direction of draining pathway. The relationship between severity and shunt volume was inexplicable in many cases. However, close correlations appeared to exist between ocular hypertension and drainage pathways toward the orbit, between cranial nerve signs and drainage pathways toward the posterior fossa, and between headache and drainage pathways toward the cortical veins.

Adult↗

PubMed1992

[Effects of sodium bicarbonate on the end-tidal CO2,PaCO2, HCO3-, PH and cerebral blood flow].

To estimate the quantitative reactivity of cerebral blood flow (CBF), the effects of sodium bicarbonate on the end-tidal CO2, arterial PaCO2, HCO3-, PH and CBF were examined. The CBF was measured by 133Xe inhalation method with ring type SPECT (HEADTOME). Activation study with sodium bicarbonate administration was performed after 30 minute of resting study, and the reactivity of each parameters was investigated. The arterial HCO3- and PH increased with similar reactivity, but PaCO2, end-tidal CO2 and CBF in the non-injured hemisphere changed with irregular reactivity. The excellent correlation between PaCO2 and end-tidal CO2 was vanished by the administration of sodium bicarbonate. The reactivity of CBF did not correlate with reactivity of PaCO2 and end-tidal CO2, but correlated with arterial HCO3- and PH. Thus the measurement of arterial HCO3- and PH may be indispensable to estimate the CBF reactivity with the administration of sodium bicarbonate.

Aged↗

PubMed1992

[Correlation between sequential changes in angiographical findings and clinical deteriorations during management for dural AVM of the cavernous region].

The authors treated five patients with dural arteriovenous malformation of the cavernous region (DAVM) by cervical compression procedure as the initial treatment. In four of five patients clinical symptoms were aggravated during that period. The period between the beginning of cervical compression and the deterioration of clinical symptoms ranged from 11 to 20 days. In three of four patients, the angiography examined at the time of deteriorations confirmed the same amount of A-V shunt flow and otherwise the remarkable decrease of the draining pathway compared to the findings of the angiogram performed before the management. The angiography examined at the time of the remission of the symptoms showed the increase of the draining pathway in two patients and the resolution of the DAVM in another. These findings indicate that clinical courses of the DAVM and the amount of the draining pathway correlate to each other and that cervical compression procedure may occlude the important draining pathway of the DAVM.

Adult↗

PubMed1992

[Intra-bullous ventilation of giant bulla: does slow ventilation space on multi-breath nitrogen washout test mean that giant bulla is present?].

Intra-bullous ventilation and uneven ventilation in patients with giant bulla were studied by the multi-breath nitrogen washout and 133Xe washout tests. Fourteen patients underwent the nitrogen washout test before and after bullectomy; 2 of them also underwent the 133Xe washout test before surgery. After bullectomy, pulmonary nitrogen clearance delay and alveolar dilution rate (ADR) of slow ventilation space improved significantly (p less than 0.01) from 202.5% to 51.5%, and from 0.98 to 0.95, respectively. The dilution rate of 133Xe in the bullous region, based on the 133Xe clearance curve, showed the same values as the nitrogen washout test. Therefore, we considered that bullous ventilation could be estimated by the ADR of the nitrogen washout test and that uneven ventilation resulted from the ADR difference between the giant bulla and the nonbullous lung. When the nonbullous lung region was emphysematous, however, it was impossible to estimate the intra-bullous ventilation from the nitrogen washout test.

Adolescent↗

PubMed1991

Noninvasive identification of significant narrowing of the left main coronary artery by dipyridamole thallium scintigraphy.

To evaluate the usefulness of dipyridamole thallium scintigraphy with low-level exercise for the identification of left main (LM) coronary artery disease (CAD), 466 consecutive patients with CAD were studied. Thirty-eight patients (8%) had LM stenosis (diameter narrowing greater than or equal to 50%). The LM scintigraphic pattern was present in 9 of 38 patients with LMCAD and 38 of 428 CAD patients without LMCAD (24 vs 9%; p less than 0.005). This pattern was present in 6 of 9 patients with LMCAD without right CAD and in only 3 of 29 patients with LM and right CAD (67 vs 10%; p = 0.0005). Patients with LMCAD had a higher incidence of premature cessation of low-level exercise (53 vs 21%; p less than 0.0001), chest pain (68 vs 48%; p less than 0.02), blood pressure decrease of greater than or equal to 20 mm Hg (44 vs 16%; p less than 0.002) and greater ST depression (0.17 +/- 0.13 vs 0.06 +/- 0.10 mV; p less than 0.001) during dipyridamole loading than patients without LMCAD. Stepwise discriminant analysis revealed that the LM scintigraphic pattern and markers of ischemia during dipyridamole loading best identified (p less than 0.0001) patients with LMCAD without right CAD (sensitivity 67%, specificity 91%), but this predictability is no better than the LM scintigraphic pattern alone. The combination of clinical markers of ischemia during dipyridamole loading and scintigraphic findings of diffuse slow washout, extensive fixed defects and the LM pattern best identified (p less than 0.0001) patients with LM and right CAD (sensitivity 72%, specificity 80%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Molecular cloning and primary structure of rat thyroxine-binding globulin.

Rat thyroxine-binding globulin (TBG) cDNAs were isolated from a rat liver cDNA library by using a human TBG cDNA as a probe. From two overlapping cDNA inserts, an aligned cDNA sequence of 1714 nucleotides was obtained. There was 70% homology with human TBG cDNA over the span of 1526 nucleotides. In order to confirm that the cloned cDNA encodes rat TBG and to localize the NH2-terminal amino acid of the mature molecule, the protein was purified by affinity chromatography and subjected to direct protein microsequencing. The NH2-terminal amino acid sequence was identical with that deduced from the nucleotide sequence. The rat TBG cDNA sequenced consisted of a truncated leader sequence (35 nucleotides), the complete sequence encoding the mature protein (1194 nucleotides) and the 3'-untranslated region (485 nucleotides), containing two polyadenylation signals. It was deduced that rat TBG consists of 398 amino acids (Mr = 44,607), three NH2-terminal residues more than human TBG, with which it shares 76% homology in primary structure. Of the six potential N-glycosylation sites, four are located in conserved positions compared to human TBG. Northern blot analysis of rat liver revealed an approximately 1.8-kilobase TBG mRNA. Its amount increased markedly following thyroidectomy and decreased with thyroxine treatment in a dose-dependent manner.

Amino Acid Sequence↗