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Biomedical subjects

H Park

Publications and source records attributed to H Park.

At least 307 records · Page 17Linked to original sources
PubMed1990

Morphological characterization of surface-induced platelet activation.

Morphological changes of platelets activated on glass and dimethyldichlorosilane-treated glass were investigated using video microscopy. The platelet morphological changes were quantified by measuring the area and circularity of spreading platelets. In addition, re-organization of cytoskeletal structures of spread platelets was examined. The effects of precoated albumin and fibrinogen on the platelet spreading kinetics were examined as a function of surface protein concentrations. Results showed that platelet shape changes were very sensitive to the surface concentration of precoated proteins. In general, platelets on fibrinogen-precoated surfaces spread fully to a circular shape and developed an extensive inner filamentous zone. In the presence of albumin on the surface, however, platelets could not spread fully and the development of the inner filamentous zone was very poor. For both albumin and fibrinogen, the maximum effects of precoated proteins on platelet shape changes were observed when the surface protein concentration reached the monolayer concentration.

Adsorption↗
PubMed1990

Increase in glucose-stimulated insulin release and insulin biosynthesis in isolated pancreatic islets from D-galactosamine-treated rats.

Insulin secretion in response to glucose, glucose-stimulated insulin biosynthesis and insulin content was studied in pancreatic islets freshly isolated from male Wistar rats (150-200 g) with galactosamine-induced hepatitis. Animals were sacrificed by decapitation 3, 6, 12 and 24 hours after a single intraperitoneal injection of 500 mg/kg of galactosamine. Isolated islets prepared by collagenase method were perifused in Swim's medium with 20 mM glucose at 37 degrees C up to 30 minutes. Samples were taken at 2-10 min intervals for insulin assay. Insulin biosynthesis was assessed by the incorporation of [3H]-leucine into immunoprecipitable products (insulin and proinsulin) in pancreatic islets after 120 min incubation with 20 mM glucose. Glucose-stimulated insulin secretion was significantly increased at 6, 12 and 24 hours following the administration of galactosamine compared to control. The rate of insulin biosynthesis was stimulated to 170, 138 and 185% of control level 3, 6 and 12 hours after galactosamine-treatment, respectively. Significant increase in insulin content of islets was found 24 hours after galactosamine treatment, following the increased insulin biosynthesis. The present results indicate that pancreatic B cell function is activated in early stage of acute liver injury.

Alanine Transaminase↗
PubMed1990

Suicide by captopril overdose.

We report a case of a 75 year-old male who committed suicide by taking an overdose of captopril. He took approximately ninety 12.5 mg captopril tablets. The postmortem plasma concentration of captopril was 60.4 mg/L. A review of the medical literature revealed five cases of captopril overdose all from unsuccessful suicide attempts. To our knowledge, this is the first case report of fatal captopril overdose with the measurement of plasma concentration of the drug.

Aged↗
PubMed1990

Demographic and socioeconomic characteristics of Korean Americans in the United States in 1980.

"Based on the analysis of 1980 [U.S. Census] Public-Use Microdata Samples, this article demonstrates that the Korean immigrant stream, particularly men, has been very selective even before the 1965 reform.... Despite the educational superiority and somewhat positive occupational position, Korean men in the U.S. are seriously disadvantaged in income regardless of nativity status. Korean Americans are not as successful as whites in translating their education into occupation and income; they are better educated for the same job, but experience a lower income return to the same education and the same occupation."

Americas↗
PubMed1989

Immunophenotypic spectrum of plasma cell leukemia.

Four cases of plasma cell leukemia (PCL) are reported that illustrate the variable immunotype of this disorder in contrast with the immunologic profile described for normal B-cell maturation and typical multiple myeloma (MM). Mature B-lymphocytes express B1 antigen (Ag) and surface immunoglobulin (SIg) whereas maturation to the plasma cell stage is accompanied by loss of these immunologic markers and expression of T10 Ag, plasma cell Ag (PCA), and cytoplasmic immunoglobulin (CIg). Plasma cells from patients with MM have previously been found to express the immunophenotype of normal plasma cells. In contrast, none of the four cases reported here express an immunologic profile typical for specific B-cell differentiation stages. Only one of four cases was strongly positive for PCA but additionally expressed B1 Ag and SIg. Of the remaining three cases, all expressed T10 Ag and CIg; two cases also expressed SIg, weak PCA, and B1 Ag. All four cases were monoclonal for lambda light chains and negative for common ALL Ag (CALLA). The variable expression of mature B-cell markers and plasma cell markers demonstrates the immunophenotypic spectrum of PCL; the prognostic significance of this heterogeneity needs to be more closely examined.

Adult↗
PubMed1989

CHAPS solubilization of a G-protein sensitive 5-HT1A receptor from bovine hippocampus.

The binding of [3H] 8-OH-DPAT to membrane-bound 5-HT1A receptors from bovine hippocampus was saturable and corresponded to a single high-affinity state. Solubilization of the bovine hippocampal membranes with 10 mM CHAPS containing 200 mM NaCl, renders a preparation which binds [3H] 8-OH-DPAT with high-affinity (Kd = 1.9 nM) and is guanine nucleotide sensitive and ketanserin insensitive. 50% of [3H] 8-OH-DPAT binding activity is solubilized. The presence of GMP-P(NH)P promotes a low-affinity (Kd = 9.6 nM) state which is characteristic of receptors coupled to G-proteins. GMP-P(NH)P markedly accelerates the dissociation [3H] 8-OH-DPAT from solubilized membranes while having negligible effects on association. Thus, the agonist can activate the terniary complex rather than to promote its formation. 8-OH DPAT, WB 4101 and 5-carboxamidotryptamine dose responsively inhibit soluble [3H] 8-OH-DPAT binding with IC(50) values of 16.1, 15.6 and 1.3 nM, respectively. The CHAPS solubilized membrane preparation retains many of the [3H] 8-OH-DPAT binding characteristics of the membrane bound form.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1989

A multistate model for coronary heart disease--an application to different prevention strategies.

"The discrete-time stochastic model presented in this paper pays attention [to] the association between physiological risk factors and [coronary heart disease] morbidity as well as mortality trends. Transition probabilities are modeled as a polychotomous logistic function of risk factors. A series of separate simple logistic regression analyses...are performed as a replacement for estimating polychotomous logistic regression parameters. Data from the Finnish North Karelia Project is used to test the model." (SUMMARY IN KOR)

Biology↗
PubMed1989

Application of video-enhanced interference reflection microscopy to the study of platelet-surface interactions.

Video-enhanced interference reflection microscopy (VEIRM) was used to examine contact sites between the ventral membrane of intact platelets and underlying surfaces. It was observed that the ventral membrane in the central granulomere region of fully spread platelets was separated from the surface, while the membrane in other regions was mostly in close contact. The VEIRM image of intact platelets was compared with the video-intensified fluorescence microscopic (VIFM) image of cytoskeletal structures labeled with rhodamine-phalloidin. The VEIRM was also used to visualize the cytoskeletal structures of platelets spread on glass surfaces. Platelets were treated with Triton X-100, glutaraldehyde and acetic acid in sequence. This method was used to follow the sequence of cytoskeletal reorganization of platelets after surface-induced activation. In addition, the effects of albumin and fibrinogen on the cytoskeletal reorganization of spreading platelets were investigated. On fibrinogen-coated surfaces, platelets developed extensive inner filamentous zones which encircled the central granulomere region. In the presence of albumin, however, platelet inner filamentous zones were very poorly developed.

Actins↗
PubMed1988

Simulation of a population-based model of coronary heart disease morbidity and mortality.

"The main objective of this study is to develop a modelling strategy useful to examine and predict major trends in coronary heart disease. Once we develop a model which can mimic population changes over time, then the models can be extended to provide information on intervention effects by changing the risk factors." The model is illustrated using data for North Karelia, Finland, for the period 1972-1978. (SUMMARY IN KOR)

Biology↗