Search PubMed⌕ Search

Biomedical subjects

C Kim

Publications and source records attributed to C Kim.

At least 343 records · Page 19Linked to original sources
PubMed1992

Isolation and synthesis of a new bio-antimutagen, petasiphenol, from scapes of Petasites japonicum.

A new bio-antimutagen, petasiphenol [3-(3,4-dihydroxyphenyl)-2-oxopropyl caffeate] (1) was isolated from scapes of Petasites japonicum (AD50 = 95 micrograms/ml against UV-induced mutagenic E. coli WP2 B/r Trp-. Petasiphenol (1) and its isomer (2) were synthesized. The activity of 1 was observed in the presence of soybean oil (glyceride), although the isomer (2) did not show any activity in doses up to 300 micrograms/ml.

Antimutagenic Agents↗
PubMed1992

Cardiovascular effects of a ketamine-medetomidine combination that produces deep sedation in Yucatan mini swine.

Seven chronically instrumented Yucatan minipigs were deeply sedated with the combination of ketamine (10 mg/kg), a dissociative anesthetic, and medetomidine (0.2 mg/kg), an alpha 2-adrenoceptor agonist used as an animal sedative in Europe. Both drugs were drawn in the same syringe and administered in the left atrium via a previously inserted permanent catheter. As a result, hypertension (mean arterial pressure from 116 +/- 12 mmHg to 142 +/- 18 mmHg) occurred and was followed by bradycardia (from 107 +/- 22 bpm to 71 +/- 9 bpm). Concomitantly, both the rate of increase in ventricular pressure (48%) and ventricular wall thickening fraction (37%) decreased, thus indicating some worsening of left ventricular function. Further, systemic vascular resistance increased (290%) resulting in a reduction in cardiac output from 0.4 +/- 0.3 l/minute. Also, left ventricular end diastolic pressure initially increased (maximum 10.2 +/- 10.8 mmHg) but returned to the control level in 5 minutes. In spite of an increase in respiratory frequency (3x), PaCO2 increased and PaO2 and pH declined. Rectal temperature decreased from 38.4 +/- 0.9 to 36.0 +/- 0.8 degrees C. All of these changes were transient and returned to control levels during the follow-up period (2 hours). However, epinephrine concentration was exceptionally decreased by the drugs and stayed under the detection limit (20 pg/kg) for the entire time, whereas norepinephrine was undetectable for 10 minutes postadministration. Ketamine-medetomidine, administered in a dose that produced deep sedation, induced marked but reversible changes in most of the cardiovascular variables; there were no pedal or palpebral reflexes for 30 minutes.

Anesthesia, General↗
PubMed1991

Reduction of lupus nephritis in MRL/lpr mice by a bacterial superantigen treatment.

The effects of biweekly intravenous injections of Staphylococcus Enterotoxin B (SEB) into autoimmune MRL-lpr/lpr (MRL/lpr) mice were investigated. Rather than causing the expansion of V beta 8+ T cells, SEB administration resulted in the reduction V beta 8+, CD4-CD8- "double-negative" (DN) T cells. This was shown by FACS analysis as this putative pathogenic population was diminished in both spleen and lymph node. The symptoms of systemic lupus erythematosus (SLE) in MRL/lpr, which include high titers of anti-DNA antibodies and circulating immune complexes and proteinuria, were reduced in SEB-treated mice in a dose-dependent manner. The clinical parameters of SLE in MRL/lpr, which include lymph node hyperplasia and necrotic vasculitis, were suppressed in 50-micrograms SEB-treated mice. T cells bearing V beta 6 T cell receptor, which does not interact with SEB, were not reduced with SEB administration. Thus, disease suppression was associated with a specific reduction in the number of V beta 8+, DN T cells. These results implicate a possible therapeutic role of superantigen-based immunotherapy in V beta-restricted, T cell-dominated clinical syndromes.

Animals↗
PubMed1991

Characterization of a DNA binding activity in DNAse I hypersensitive site 4 of the human globin locus control region.

A portion of the beta-globin Locus Control Region (LCR), which included DNAse I hypersensitive site 4 (HS4), was analyzed for its interactions with nuclear extracts and its contribution to LCR activity in a functional assay. In gel retardation assays, a short fragment from HS4 formed complexes with nuclear extracts from both erythroid and nonerythroid cells, and a core protected sequence 5'GACTGGC3' was revealed by DNAse I protection and methylation interference studies. This sequence resembles the binding sites of CCAAT-family members. Purified CP-2 but not CP-1 was shown to bind this HS4 sequence in a gel shift reaction, suggesting that the HS4 binding activity shares some sequence specificity with the CCAAT-factor family. Utilizing a transient expression assay in murine erythroleukemia cells, steady-state RNA levels were measured from pairs of LCR constructs linked to distinguishable beta-globin reporter genes. A short DNA fragment from HS4 which included the binding site for this novel binding activity accounted for most of the contribution to high level expression made by the entire HS4 region.

Animals↗
PubMed1991

Spontaneous saccular cerebral aneurysm in a rat.

A saccular cerebral aneurysm was incidentally found at the bifurcation of a fenestrated anterior cerebral artery of 35-week-old Sprague-Dawley rat. The animal had been fed a normal laboratory diet. The internal lamina extended for a short distance into the neck of the aneurysm and then suddenly disappeared. The medial layer ended abruptly at the neck of the aneurysm. The aneurysmal wall consisted mainly of connective tissue, and of some poorly stained fragments of elastic lamina. No evidence of polyarteritis nodosa or any other inflammatory reaction was obtained. These findings were the same as those observed in man. Therefore, this aneurysm proved to be of truly spontaneous origin. In contrast to experimental aneurysms in rats and in monkeys, in which aneurysms are observed very often, degenerative changes of the elastic lamina in spontaneous aneurysm in the rat were confined to the neck of the aneurysm. This fact may explain partly the difference in frequency between spontaneous and experimental aneurysms in animals. The present study indicates that degenerative changes of the elastic lamina play a very important role in the development of saccular cerebral aneurysms.

Animals↗
PubMed1991

Effects of ethanol and hepatic vitamin A on the proliferation of lipocytes in regenerating rat liver.

The effects of ethanol and hepatic vitamin A on lipocyte proliferation were studied in regenerating rat livers. Positive identification of proliferating lipocytes was achieved by a double immunostaining sequence for cytoplasmic desmin and bromodeoxyuridine-labelled nuclei. Ethanol administration caused a 76 and 36% reduction in labelling indices of lipocytes 2 and 3 days after hepatectomy, respectively, thereby delaying the onset of the proliferative peak of lipocytes by 1 day compared to the control. Hepatic vitamin A did not decrease until 4 days after hepatectomy. The relationship between hepatic vitamin A and lipocyte proliferation was further evaluated in rats fed diets containing four different amounts of vitamin A. Despite the striking differences in liver vitamin A levels, the proliferative activity of lipocytes was unaffected, as measured at the peak of lipocyte proliferation 2 days after hepatectomy. These data indicate that ethanol ingestion suppresses the proliferative response of lipocytes to partial hepatectomy but that this ethanol effect is independent of changes of vitamin A levels in the liver.

Adipose Tissue↗
PubMed1991

Intraocular pressure-dependent retinal vascular change in adult chronic open-angle glaucoma patients.

Intraocular pressure (IOP)-dependent retinal vascular changes were investigated in 33 eyes of 33 adult chronic open-angle glaucoma (COAG) patients by measuring major retinal vascular calibers at the optic disc border before and after mean (+/- standard deviation) IOP reduction from 35.3 (+/- 7.2) to 16.5 (+/- 4.7) mmHg for 11.2 (+/- 13.5) weeks. Both mean arterial and venous calibers were significantly reduced (P less than 0.0001 for each), from 87.8 (+/- 14.2) and 128.3 (+/- 20.8) microns at high IOP to 82.0 (+/- 13.8) and 121.4 (+/- 18.5) microns at low IOP. Arterial and venous caliber decreases correlated positively with magnitude of IOP reduction (r = 0.503, P less than 0.01 and r = 0.555, P less than 0.001, respectively). While the IOP-dependent retinal arterial caliber change was highly significant in patients 55 years of age or younger (r = 0.636, P less than 0.01) and in the overall study group, it was not significant in patients older than 55 years (r = 0.205, P greater than 0.1). Age seems to be more influential than magnitude of IOP reduction in patients older than 55. Thus, diminished IOP-dependent retinal arterial caliber change in the elderly may be one factor contributing to the higher incidence and prevalence of glaucoma in this population.

Adrenergic beta-Antagonists↗
PubMed1991

Outbreak of neonatal listeriosis associated with mineral oil.

In June, 1989, an outbreak of nosocomial listeriosis occurred in Costa Rica. Listeria monocytogenes was isolated from 9 ill infants 4 to 8 days old who were born after the delivery of an infant with early onset listeriosis. One nosocomial infection was fatal, 2 required mechanical ventilation and 1 resulted in hemiparesis. A higher proportion of cases than other infants born during the outbreak were delivered by cesarean section (55% vs. 24%, P = 0.04). Compared with the mothers of 36 random controls, case mothers were more often primiparous (odds ratio, 6.2, P = 0.03) or received general anesthesia before delivery (odds ratio, 4.4, P = 0.09). All infants were bathed with mineral oil from a multidose container. Culture of the oil by cold enrichment grew L. monocytogenes 4b with the same electrophoretic enzyme type as the outbreak strain. We hypothesize that aspiration of contaminated oil may have resulted in systemic listeriosis. General anesthesia may have increased the risk of aspiration. Lung tissue from the infant who died showed lipid-laden macrophages consistent with oil aspiration and had evidence of L. monocytogenes DNA detected by polymerase chain reaction. This is the first nosocomial outbreak of listeriosis in which a common source suggested epidemiologically was microbiologically confirmed. The high attack rate (greater than 200 times the United States rate of perinatal listeriosis) emphasizes the susceptibility of healthy neonates to L. monocytogenes. The results of our study led to the discontinuation of the use of mineral oil for bathing neonates in Costa Rica.

Case-Control Studies↗
PubMed1991

Rapid confirmation of Listeria monocytogenes isolated from foods by a colony blot assay using a digoxigenin-labeled synthetic oligonucleotide probe.

An oligodeoxyribonucleotide probe based on the sequence of a 321-bp internal fragment of the msp gene encoding a major secreted polypeptide of Listeria monocytogenes was labeled with digoxigenin by using terminal deoxynucleotidyl transferase. The specificity of the digoxigenin-labeled probe was determined by dot blot assays. The probe reacted with all strains of L. monocytogenes tested (12 of 12 strains representing five serotypes). The probe did not react with any other Listeria species or with other gram-positive bacteria (Brochothrix, Erysipelothrix, Corynebacterium, Rhodococcus, Lactobacillus, Leuconostoc, Bacillus, Staphylococcus, and Streptococcus). The probe was used to develop a colony blot assay for the rapid confirmation of L. monocytogenes on Listeria-selective agars which had been streaked with food enrichment cultures. Forty-eight food samples were tested by conventional culture and DNA colony blot assay. The sensitivity and specificity of the DNA colony blot were 100 and 97%, respectively.

Bacterial Proteins↗
PubMed1991

Adrenal steroid receptor activation in vivo and immune function.

Recent studies have indicated significant differences among immune and other tissues in in vivo adrenal steroid receptor activation after a given hormone exposure. Nevertheless, the relationship between in vivo receptor activation and functional measures of the immune response has not been determined. Type I and type II adrenal steroid receptor binding in conjunction with mitogen-induced T-cell proliferative responses were measured in the spleens of Sprague-Dawley rats that were administered various concentrations of dexamethasone (DEX). A linear relationship between type II receptor binding and splenocyte proliferation was found, with decreases in measurable type II receptors (indicating in vivo receptor activation) being highly correlated with decreases in immune function. There was no evidence of spare type II receptors. In vitro studies using the type II receptor antagonist RU 486 confirmed that the inhibitory effect of DEX on splenocyte proliferation was mediated via the type II receptor. These findings provide a foundation for future studies evaluating glucocorticoid effects on immune system function and suggest that evidence of in vivo receptor activation may be critical for predicting when and in which tissues adrenal steroid hormones may be capable of modulating the immune response.

Analysis of Variance↗
PubMed1991

Myometrial contracture-related increases in plasma adrenocorticotropin in fetal sheep in the last third of gestation are abolished by maintaining fetal normoxemia.

Low amplitude, long-lasting epochs of myometrial activity, contractures, occur throughout the majority of pregnancy in all species studied to date. Contractures are associated with a fall in fetal oxygenation and changes in fetal behavioral state. In the present study we observed that contractures produced by the administration of 70 mU oxytocin iv to the pregnant ewe at 125-139 days gestational age (term 145-150 days) result in a fall in fetal carotid arterial PO2 of approximately 2.5 mm Hg and are followed by a rise in fetal carotid arterial plasma ACTH of 16.3 +/- 9.6 pg.ml-1 (mean +/- SEM). When the contracture-induced fall in fetal arterial PO2 was prevented by administration of oxygen to the ewe, fetal ACTH did not rise after the contracture. In conclusion, these observations demonstrate that the relatively small fall in fetal PO2 that accompanies a contracture can be sensed by the fetus and is an essential part of the stimulus to the increased secretion of fetal ACTH that accompanies a contracture. These findings support the view that myometrial activity is one of the factors that influence fetal ACTH secretion.

Adrenocorticotropic Hormone↗
PubMed1991

Relationship between apo[a] isoforms and Lp[a] density in subjects with different apo[a] phenotype: a study before and after a fatty meal.

Plasma Lp[a] levels and apo[a] isoform distribution among lipoproteins isolated by density gradient ultracentrifugation were studied in subjects with one-band or two-band apo[a] phenotypes as assessed by gradient gel electrophoresis before and after an oral fat load. There were no significant differences in the ultracentrifugal profile between fasting plasma and postprandial plasma that was freed of triglyceride-rich particles (TRP). One-band phenotypes exhibited a single symmetrical peak in the density gradient, whereas two-band phenotypes exhibited a multi-modal distribution. Low molecular weight apo[a] isoforms were preferentially associated with low density Lp[a] whereas high molecular weight apo[a] isoforms were found with high density Lp[a] particles. Feeding a high fat meal caused no significant increase in the total plasma level of Lp[a]. However, the isolated TRP contained the apoB-100-apo[a] complex in a quantity that represented only about 1% of its total amount in the fasting plasma. In all cases the apo[a] isoforms present in TRP were also present in the fasting plasma; however, in the two-band apo[a] phenotypes the ratio of the slow over the fast migrating band was in all cases about eightfold higher in TRP than in the fasting plasma. These observations indicate that postprandially a small percentage of apoB-100-apo[a] associates with TRP and suggest that this complex may derive from de novo synthesis rather than from a pre-existing Lp[a] plasma pool. The liver would be the source of the complex due to the presence in the latter of apoB-100.

Adult↗
PubMed1990

Resolution of recent evolutionary divergence among Escherichia coli from related lineages: the application of pulsed field electrophoresis to molecular epidemiology.

Escherichia coli infecting the urinary tract and other extraintestinal sites are often identical in many phenotypic and genotypic characteristics. To discriminate among pathogenic E. coli isolates, chromosomal DNA was digested with restriction endonucleases that recognize eight base pair sequences and the resulting 20-25 fragments were resolved by pulsed field gel electrophoresis (PFGE). Different restriction fragment profiles were detected for isolates obtained from different patients, including isolates of the same evolutionary lineage that were identical in electrophoretic type, serotype, and antibiotic sensitivities. In contrast, isolates obtained from separate sites of infection within the same patient had identical restriction profiles. These results indicate that PFGE can resolve recent evolutionary divergence within E.coli lineages and, consequently, offers a powerful new means for precisely performing molecular epidemiology. In addition, these studies provide genetic evidence that E. coli urinary tract infection within a given patient is typically due to the expansion of a single bacterial clone.

Biliary Tract Diseases↗