Biomedical subjects
Publications and source records attributed to M K Kim.
In the course of a search for acyl-CoA : cholesterol acyltransferase (ACAT) inhibitors from natural sources, new types of ACAT inhibitors were isolated from the extract of Magnolia obovata leaves, and identified as obovatol, honokiol, and magnolol. The active compounds inhibit rat liver ACAT with IC50 values of 42, 71, and 86 microM, respectively.
In the course of our screening program for acyl-CoA : cholesterol acyltransferase (ACAT) inhibitors from Korean herbal medicines, ACAT inhibitors were isolated from the hairy roots of Panax ginseng (Araliaceae) and identified as panaxynol, panaxydol, panaxydiol, and panaxytriol. These active compounds inhibit rat liver ACAT with IC50 values of 94, 80, 45 and 79 microM, respectively.
Mammalian embryos are known to exhibit delayed development and have lower hatching rates in vitro than in vivo because of inadequate culture condition. These discrepancies may be due to a deficiency of the paracrine factors and proteolytic enzymes which exist in the oviduct and uterus. In order to evaluate the effects of proteases on embryonic development and hatching, 2-cell mouse embryos were cultured for 72 h with or without proteases. The addition of 1.0 microg/ml pronase (PE) and/or 0.1 microg/ml proteinase K (PK) did not affect embryonic development up to the blastocyst stage (94.1% versus 88.2%; 92.2% versus 90.2%, respectively) but significantly increased the hatching rate (60.4% versus 39.2%, 71.8% versus 35.3%, respectively). However, the addition of alpha-chymotrypsin (Chymo) was detrimental to embryonic development and hatching. Changes in the structure of the zona pellucida (ZP) structure of embryos which had been cultured in human tubal fluid (HTF) medium with PE and PK were assessed by fluorescein isothiocyanate-conjugated (FITC)-casein. Embryos cultured in HTF-PE and PK were not stained with FITC-casein. When these embryos were cultured within oviducts, their perivitelline space (PVS) became strongly stained with FITC-casein which was easily removed by phosphate-buffered saline washing. This suggests that PE and PK altered the structure of the ZP. We suggest that the addition of PE and PK to culture media may accelerate the hatching of embryo, by structurally altering the ZP and PVS. This may provide a valuable and effective assisted hatching technique for human in-vitro fertilization-embryo transfer.
A group of 23 elderly outpatients with dysthymic disorder participated in a 13-week fluoxetine trial. Twelve responders received open continuation treatment and subsequently discontinued fluoxetine (mean: 32 weeks on medication). During the 24 weeks after discontinuation, 6 of the 12 patients relapsed. Clinical features, dose, and duration of fluoxetine treatment were not predictive of relapse. The 50% relapse rate in this small sample is lower than that reported in young adult dysthymic patients but is high enough to warrant clinical caution.
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In this study, we investigated the ability of L-lysine to block renal uptake of 125I- or 99mTc- labeled Fv fragments. Anti-Tac disulfide-stabilized Fv fragment (dsFv) was derived from a murine monoclonal antibody that recognizes the alpha subunit of the interleukin-2 receptor (IL-2R alpha). The 125I- or 99mTc-labeled dsFv was injected i.v. into non-tumor-bearing nude mice or into nude mice bearing SP2/Tac (IL-2R alpha positive) and SP2/0 (IL-2R alpha negative) tumor. We then evaluated the pharmacokinetics of L-[3H]lysine and the effect of L-lysine dose, timing of administration, and route of delivery on catabolism and biodistribution of i.v. dsFv. Peak renal uptake of i.v. or i.p. injected L-[3H]lysine occurred within 5 and 15 min, respectively. The kidney uptake of L-lysine exhibited a dose-response effect. When L-lysine was coinfused or injected shortly before dsFv, renal uptake of dsFv was blocked to < 5% of the control, but longer intervals were less effective. Aminosyn II and Travasol 10% (parenteral amino acid solutions) also blocked renal uptake of radiolabeled dsFv. Administration of L-lysine did not alter the blood kinetics and slightly increased the tumor uptake of dsFv, but it did prevent catabolism in the kidney and resulted in lower amounts of catabolites in the serum and urine. In conclusion, we have shown that a blocking dose of lysine, injected with or immediately before the injection of radiolabeled dsFv, is most effective in blocking the renal uptake of dsFv. This is consistent with the rapid uptake of L-[3H]lysine by the kidney and is further substantiated by the relative ineffectiveness of lysine injected immediately after the radiolabeled dsFv injection.
Mouse oocytes were previously observed to undergo structural changes involving the perivitelline space (PVS) within the oviduct following ovulation, as visualized by staining with fluorochrome-protein conjugates. In the present study, this phenomenon was investigated in detail to determine the role of the oviduct and oocyte. Mouse ovarian oocytes matured in vitro were further incubated in medium or within explanted oviducts in vitro for varying periods of time and then stained with fluorescein isothiocyanate (FITC)-casein. Twenty percent of oocytes incubated within explanted oviducts for 3 hr showed distinct fluorescence staining of the PVS, whereas after 20 hr incubation, most (89%) oocytes were similarly stained. In contrast, no ovarian oocytes was stained when incubated in medium alone. Puromycin treatment during incubation of oocytes within explanted oviducts produced a dose-dependent decrease in the percentage of oocyte exhibiting PVS staining after FITC-casein exposure. FITC-casein staining of the PVS also occurred in all oocytes following incubation of in vitro-matured oocytes with oviductal tissue extract. In contrast, no oocytes incubated with serum exhibited fluorescence staining. Additionally, the PVS of oocytes failed to stain after incubation with either 0.001% of trypsin- or heat-treated oviductal homogenate. When zona pellucida (ZP) ghosts, devoid of ooplasm, were incubated within explanted oviducts, their PVS was stained brightly following FITC-casein treatment. From these results, it is concluded that proteinaceous material(s) secreted by the mouse oviduct is responsible for the fluorescence staining of the PVS of mouse oocytes and of ghost ZP. The ooplasm does not appear to play any role in altering the properties of the PVS staining.
STUDY OBJECTIVE: To determine whether historical or clinical variables can accurately discriminate among children, experiencing a first episode of bronchospasm, with chest radiography findings that are normal, consistent with reactive airway disease (RAD), or pathologic. METHODS: We assembled a prospective case series of patients in our tertiary, academic, pediatric emergency department. All patients aged newborn to 18 years presenting to the ED with their initial episode of wheezing were enrolled. RESULTS: Six hundred thirty-three patients presented to the ED during the study period. Pathologic radiographic findings were identified in 39 (6.2%). Radiographs revealing normal findings and evidence of RAD were noted in 25.4% and 68%, respectively. No single variable accurately predicted all pathologic radiographs. Discriminant function analysis identified nine variables, which we combined into a model. The model failed to accurately discriminate among patients with radiographs revealing evidence of a pathologic condition, normal chest findings, and RAD. CONCLUSION: No clinical variables, isolated or combined into a model, accurately identify patients with pathologic radiography findings. Continued use of chest radiography as a diagnostic intervention in the initial episode of childhood bronchospasm is recommended.
In the present study, a lepidopteran cell line (Ld-652Y, from the gypsy moth, Lymantria dispar) exposed to Hyposoter fugitivus polydnavirus (HfPV) was found to display a variety of cytopathic effects. These included a transient inhibition of cell proliferation, rounding up, aggregation and apoptosis. In addition, unusual paracrystalline structures appeared within the lumen of the rough endoplasmic reticulum; similar structures were observed in the spherulocytes of parasitized Malacosoma disstria. Following Coomassie Blue staining, two new cell-associated polypeptides were detected; one of these, an 8 kDa polypeptide, could also be observed following exposure of LD-652Y cells to media taken from infected cultures or to cell-free haemolymph from parasitized M. disstria. After a period of 2-4 weeks, the L. dispar cell cultures were observed to largely recover from the effects of exposure to virus, and resumed proliferation; "transformed' cell populations tended to form aggregates, and adhered less tightly to the substrate. Viral DNA was stably maintained in all recovered cell lines, possibly in chromosomally integrated form.
Expression of the human thyrotropin beta (hTSHbeta) gene is restricted to thyrotrophs, at least in part, by silencing. Using transient-transfection assays, we have localized a silencer element to a region between -128 and -480 bp upstream of the transcription initiation site. The silencing activity was overcome in a thyrotroph-specific manner by an unknown enhancer located in the sequences at -approximately 10000 to -1200 bp. The ubiquitous POU homeodomain protein Oct-1 recognized the A/T-rich silencer element at multiple sites in gel mobility shift assays and in vitro footprinting analyses. The silencing activity of Oct-1 was localized in its C-terminal alanine-rich domain, suggesting that Oct-1 plays a role in silencing of the hTSHbeta promoter. Further, a significant fraction of Oct-1 was shown to be associated with the nuclear matrix, and the hTSHbeta silencer region was tethered to a nuclear matrix of human cells in vivo, suggesting a possible role of the Oct-1-hTSHbeta silencer region interaction in chromatin organization.
The heat transfer characteristics of a hydroponic system were experimentally verified after theoretical establishment and the effect of nutrient solution cooling on the plant temperature was investigated. About 96 percent of the total heat flow transferred from culture bed to nutrient solution was the conductive heat through planting board and partitioning materials. The average and maximum temperatures of the leaf lettuce decreased 0.6 and 1.5 degrees C., respectively, with cooling of nutrient solution by 6 degrees C. A numerical model for prediction of cooling load of nutrient solution in a hydroponic greenhouse was developed, and the results from the simulation model showed a good agreement with those from experiments. A mechanical cooling system using the counter flow type with double pipes was developed for cooling the nutrient solution. Also the heat transfer characteristics of the system were analyzed experimentally and theoretically, and compared with the other existing cooling systems of nutrient solution. The cooling capacities of three different systems, which used polyethylene tube in solution tank, stainless tube in solution tank, and the counter flow type with double pipes, were comparatively evaluated.
BACKGROUND: Despite their prevalence, little is known about the treatment of mild depressive syndromes in older patients. The purpose of this study was to evaluate the efficacy of fluoxetine in dysthymic disorder in the elderly. METHOD: Twenty-three elderly outpatients with dysthymic disorder (DSM-III-R criteria) entered a 13-week study of fluoxetine (2-week placebo run-in period and 11 weeks of fluoxetine treatment with a dose range of 20-60 mg/day). Ratings to assess clinical response included the Hamilton Rating Scale for Depression (HAM-D), the Clinic Global Impression (CGI), and the Cornell Dysthymia Rating Scale (CDRS). RESULTS: Nine patients (39%) had never received psychiatric treatment during the index episode, despite a long duration of illness (mean +/- SD = 18.5 +/- 17.1 years). Twenty of the 23 patients completed the entire study. The mean +/- SD HAM-D (24-item) score decreased from 14.6 +/- 3.7 to 7.9 +/- 5.0 during the trial, and the CDRS score decreased from 28.1 +/- 9.1 to 15.7 +/- 10.0. When response criteria of a 50% reduction from baseline in the HAM-D score, final HAM-D score < or = 8, and a CGI score of 1 or 2 (very much or much improved) were used, 12 (60%) of the completers were responders. Side effects were uncommon, and the fluoxetine was generally well tolerated. CONCLUSION: These preliminary findings suggest that fluoxetine is an effective treatment in elderly patients with dysthymic disorder. Double-blind, placebo-controlled studies are warranted.
With the changes in trends of disease pattern from infectious to chronic degenerative disease, cardiovascular disease has been considered as the major cause of death in Korea. Numerous studies have been done on the antioxidant effects of some vitamins in the prevention of chronic illness, but not many in relation to the cardiovascular disease. Therefore, the relation between antioxidant vitamins, mainly alpha-tocopherol (alpha-T) and beta-carotene (beta-C), and coronary artery disease (CAD) such as angina pectoris and myocardial infarction has been investigated in this study. The blood samples were obtained from the CAD patients who were angiographically diagnosed within a month (100 case group). Patients who had an experience of PTCA or CABG were excluded from the study. Control subjects were healthy adults who had normal EKG values, no chest pain and no past history of cardiac disease (100 control group). All subjects were free for serum lipid lowering drugs. Serum alpha-T and beta-C were analysed using HPLC. In addition to antioxidant vitamins, serum lipids (total cholesterol, HDL, TG) were also measured. Each case and control was matched in terms of age and sex. And all the CAD risk factors such as blood pressure, smoking, alcohol, serum lipid profile and BMI were adjusted to determine pure effect(s) of alpha-T and beta-C on the CAD. The concentrations of both alpha-T and beta-C were significantly lower in the CAD group than those in control group (P < 0.05); in CAD group, mean values of alpha-T and beta-C were 11.9 +/- 7.2 (micrograms/ml), 35.8 +/- 3.1 (micrograms/dl) respectively. As for the levels of beta-C, it shows inverse relation with age, but not for the alpha-T levels. Serum levels of both vitamins did not show any significant differences in terms of sex, but men have a tendency o higher levels of beta-C, but lower levels of alpha-T.
The crystals found in sporulation extracts of Bacillus thuringiensis (Berliner) contain proteins that are highly toxic to insects. Different crystal proteins exhibit distinct specificities for restricted groups of insects. An uncharacterized strain of B. thuringiensis (BtS2), derived from China, was found to carry several crystal protein genes and to be toxic to a wide variety of insects, including some coleopterans. Surprisingly, the coleopteran toxicity was traced to a CryIB-class protein. The previously cloned CryIB protein from B. thuringiensis ssp. thuringiensis strain HD-290-I, which was believed to be lepidopteran-specific, was also found to be toxic to at least two species of coleopteran larvae under certain conditions. In contrast to CryIB toxicity toward lepidopterans, the coleopteran activity of CryIB is enhanced by solubilization and by truncation with trypsin prior to administration. The magnitude of this effect varies with the host species and is reversed for the one lepidopteran tested. These results suggest that, for at least some insects, the apparent host specificity of CryIB may depend both on differences in midgut environment and on differences in toxin-receptor interaction. The results of insect toxicity experiments with a series of deletion mutants allowed definition of a CryIB protein fragment of ca. 65 kDa as the smallest peptide that retains bioactivity against both lepidopteran and coleopteran larvae. Deletions smaller than this resulted in the production of a protein that was nontoxic to both lepidopteran and coleopteran larvae.
OBJECTIVES: We conducted an analysis of correlation between histological grading of chronic gastritis and the presence of H. pylori infection to investigate if H. pylori influences histological severity of chronic gastritis in Korean patients with peptic ulcers. METHODS: Gastroscopic antral biopsy specimens and peripheral venous blood were taken from 80 patients with gastric or duodenal ulcers. H. pylori was identified microscopically in sections with Giemsa staining and quantitative grading of cultured H. pylori was reported on a scale 0 to 3. The histopathological features of biopsy specimens were reported according to the Sydney classification of chronic gastritis. Serum gastrin and pepsinogen concentrations were measured by radioimmunoassay. RESULTS: H. pylori was identified in 62.5%(20 of 32 GU, 30 of 48 DU) of the study group. Gastric clonization rate of H. pylori did not increased with age. Forty of 50 biopsy specimens with H. pylori and also 23 of 30 biopsy specimens without H. pylori showed active chronic gastritis. There was no significant correlation overall between the presence of H. pylori and histological grading of chronic gastritis, including activity, and also no association was found between the quantitative grading of H. pylori and the histological grading of chronic gastritis. With and without H. pylori, a mean of serum gastrin concentration(79.4 +/- 4.30 pg/ml and 80.2 +/- 31.9 pg/ml)showed no significant difference, but a mean of serum pepsinogen concentration(87.7 +/- 41.6 ng/ml and 119 +/- 34.4 ng/ml) showed significant difference between the populations with and without H. pylori(p = 0.001). CONCLUSIONS: The influence of H. pylori on histological grading of chronic gastritis in Korean is less than that in prior studies of Western countries, and further investigation of pathogenesis of H. pylori in chronic gastritis and peptic ulceration is necessary.
Achieving high efficiency in hospital bed operations becomes an important aim of hospital management, as managerial environment of hospitals has been increasingly competitive in Korea. Many authors have made studies on higher occupancies, but very few about systems characteristics of the time serial data as well as decision behavior on bed operations. For those topics overlooked, this paper applies Wu's Dynamic Data Systems Analysis, for which an ARMA model is developed and its characteristic roots are analyzed. The results include such information as periodic nature of data, strength and effects of disturbances, based on which interpretations are provided tuned to the target system's operational aspects. For this work, data were collected and processed for two different periods of time, October 1990 to April 1991 and October 1993 to April 1994. While the average occupancies between two periods are not statistically different, the effect of error disturbances was managed better in 1990 than in 1993. And the restoring forces from fluctuations are almost the same between the periods of comparison. With this analysis, conclusions are summarized: in both periods, short-term flexibility in patient admissions and discharges are good, but long-term management of hospital census trend needs to be improved by developing the system of controlling patient admissions and discharges. For the improvement, some possible approaches are suggested for future studies.
Neovascularization or angiogenesis is an essential yet poorly understood component of the healing process. In wound healing research, there is a lack of models enabling quantitative and continuous measurements of wound neovascularization. The hairless mouse ear wound model permits quantitative measurements of wound epithelialization and neovascularization continuously throughout the healing process. On the ears of male homozygous (hr/hr) hairless mice, standardized circular full thickness dermal wounds are produced; then, using vital microscopy, these two processes are directly viewed and measured at day 0 and every third day thereafter until these are complete. This model system and its application to clinically relevant situations are reviewed.
Streptomyces exfoliatus SMF19 produced two types of extracellular beta-lactamase-inhibiting proteins, 48 (beta LIP-I) and 33 (beta LIP-II) kDa. The inhibition mode of beta LIP-I on Bacto Penase and benzylpenicillin as substrates was uncompetitive (i.e., both Km and Vmax were changed), while that of beta LIP-II was noncompetitive (i.e., only Vmax was changed). The inhibition constants of beta LIP-I and beta LIP-II were 0.62 x 10(-4) and 2.74 x 10(-1) mumol, respectively. The N-terminal amino acid sequence of beta LIP-I was NH3-*-S-T-V-F-D-L-V-*-L-G, and that of beta LIP-II was NH3-D-F-*-V-F-D-L-E-A-T-D-E.