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Biomedical subjects

M Kim

Publications and source records attributed to M Kim.

At least 379 records · Page 21Linked to original sources
PubMed1991

Inhibition of azoxymethane-induced colon carcinogenesis in rat by green tea polyphenol fraction.

The effect of green tea polyphenol fraction (GTP) on azoxymethane(AOM)-induced colon carcinogenesis was investigated in male Fischer rats. The rats were given AOM (7.4 mg/kg body weight) s.c. once a week for 10 weeks. A week after the treatment, they were divided into three groups: AOM-control (26 rats), AOM-GTP1 (26 rats) and AOM-GTP2 (25 rats). AOM-GTP1 and AOM-GTP2 groups respectively received 0.01 and 0.1% GTP in drinking water from week 11 to 26. AOM-control group received tap water throughout this experiment. Autopsy on week 26 showed that tumor incidence and average numbers of tumors per rat in the AOM-GTP1 and AOM-GTP2 groups were significantly lower than those of the AOM-control group: 38.1% and 47.6% versus 77.3%; 0.6 and 0.7 versus 1.5. Thus, it was concluded that GTP inhibited the development of AOM-induced colon carcinogenesis. The inhibition by GTP did not show significant dose dependence.

Animals↗
PubMed1991

Ongoing pain as a mental workload indexed by P300 depression: discrimination of real and feigned pain conditions.

Two groups of subjects were formed. One, a real pain group, was subjected to aversive pressure on the fingernail surface during pain-only and pain-tracking conditions. The second group (feigned pain) was instructed to feign pain during corresponding runs in which fingernail pressure was applied at a just noticeable (not painful) level. Both groups also simultaneously performed an auditory oddball (.8/.2) task during their pain-only and pain-tracking conditions, as well as during an initial (baseline-1) and final (baseline-2) baseline condition in which only the oddball task was performed. Oddball-evoked P300 amplitudes were significantly different for the groups during the pain-tracking and baseline-2 conditions, with the amplitudes smaller in the real pain groups in both conditions. The pain-only and pain-tracking conditions in both groups caused significant P300 reductions in comparison with baseline-1 values. P300 latencies did not differ as a function of either groups or conditions. 100% of the real pain subjects and 67% of the feigned pain subjects could be correctly classified using P300 amplitude-derived indices.

Adult↗
PubMed1991

Protection of rats against dental caries by passive immunization with hen-egg-yolk antibody (IgY).

Hen-egg-yolk antibody (IgY) was prepared against Streptococcus mutans MT8148 serotype c that was cultivated in medium containing sucrose, and it was used in passive caries-immunity studies. Specific pathogen-free rats infected with S. mutans MT8148 (c) and fed with a cariogenic diet containing more than 2% immune yolk powder developed significantly lower caries scores than did the ones infected with the same strain and fed with a diet containing only control yolk powder obtained from non-immunized hens. Similar results were obtained in an experiment with rats infected with S. mutans JC-2 (c) strain. Rats provided a diet supplemented with 0.5% immune water-soluble protein fraction containing S. mutans-specific IgY and challenged with S. mutans MT8148 exhibited significantly fewer caries lesions, compared with control rats on the normal diet.

Administration, Oral↗
PubMed1991

The behavior of L-ascorbic acid in the healing process of dorsal wounds in guinea pigs.

The behavior of L-ascorbic acid (AsA) in the healing process of wounds in guinea pigs was investigated by determining AsA and dehydroascorbic acid (DAsA) levels. Dorsal skin wounds of guinea pigs fed AsA-deficient diets for 10 days were surgically induced, and the animals were intraperitoneally supplemented with 0, 0.5, 5, 50 mg/day of AsA for 4 days, respectively. The animals were sacrificed, and the amounts of AsA and DAsA in healing skin wound and intact skin were determined by high-performance liquid chromatography (HPLC). It was found that total AsA levels in the healing wound of the animals in AsA-supplemented groups were almost similar to those in intact skin, respectively. However, DAsA levels in the healing wounds on day 4 of the healing period are significantly higher than those not only in the intact skin but also in the completely regenerated skin on day 14 of the healing period. From these results, it was suggested that the wound healing process was accompanied by the oxidation of AsA, moreover, the reduction of DAsA to AsA did not sufficiently occur in vivo.

Animals↗
PubMed1991

Synthesis and biological activity of novel 3-(2-propenyl)-cephalosporins. II. Preparation of prodrugs.

Three prodrug esters (2a approximately 2c) of 3-(2-propenyl)cephem (1a) have been prepared and their oral absorption was determined in rats and mice. While pivaloyloxymethyl ester (2a) did not improve the oral absorption of the parent cephem 1a, [(1-methyl)ethoxycarbonyloxy]ethyl ester (2b) and (5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl ester (2c) improved oral absorption by a factor of five.

Absorption↗
PubMed1990

Effects of pertussis toxin on caudate neuron electrophysiology: studies with dopamine D1 and D2 agonists.

The selective D1 and D2-agonists SKF-38393 and N-0437 respectively, were tested in caudate pretreated with PT. A paired recording paradigm was used where the contralateral untreated caudate served as a control. Micropipettes were used to locally apply SKF-38393 and N-0437 onto neurons in both control and PT-pretreated caudate. A significant attenuation of the responses to the D2 agonist were observed after PT administration. Only 1 out of 12 cells tested on the PT side demonstrated any response to locally applied N-0437, whereas 90% of the neurons responded to the drug on the control side. Neurons from both the PT-pretreated and control caudates responded to locally applied SKF-38393. In addition to the specific D1 and D2 receptor agonists, DA and the indirect dopamine agonist PCP were tested for changes in responsiveness. Dopamine was equally efficacious at both control and PT-pretreated caudate neurons, which suggest that dopamine locally applied from the micropipette can interact with the unperturbed D1 receptors in the PT-pretreated caudate. On the other hand, the response to PCP was significantly attenuated after PT administration, which suggest that endogenously released DA preferentially interacts with the D2 receptor subtype. Taken together these data suggest an important role for the D2 receptor in the physiology of dopamine responsiveness in the caudate nucleus.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1990

Pharmacological evidence for involvement of the sympathetic nervous system in the increase in renin secretion produced by a low sodium diet in rats.

To determine the degree to which increased sympathetic activity contributes to the increase in renin secretion produced by a low sodium diet, the beta-adrenergic blocking drug propranolol or saline vehicle was injected through indwelling jugular cannulas in rats fed a normal diet and rats fed a low sodium diet for 9 days. Plasma renin activity (PRA) and plasma renin concentration (PRC) were elevated by the low sodium diet, and these values were reduced 42-45% by propranolol, although they were still higher than in the normal diet controls. Plasma corticosterone was moderately elevated in cannulated rats on regular diet, compared to decapitated controls, but corticosterone did not differ between cannulated and decapitated rats on low salt diet; propranolol reduced plasma corticosterone. However, PRA and PRC were comparable in cannulated rats and decapitated controls on both the normal and the low sodium diets, and propranolol did not produce a significant reduction in PRA and PRC in rats fed the normal diet. This indicates that the effects of propranolol on PRA and PRC in the low sodium rats were not simply due to reduction of a stress-induced increase in renin secretion. The results indicate that increased sympathetic activity makes a substantial contribution to the increase in renin secretion produced by 9 days of dietary sodium restriction.

Adrenocorticotropic Hormone↗
PubMed1990

Gastroenteritis in suckling mice caused by human rotavirus can be prevented with egg yolk immunoglobulin (IgY) and treated with a protein-bound polysaccharide preparation (PSK).

Oral inoculation of human rotavirus MO strain (serotype 3) into 5-day-old BALB/c mice cause gastroenteritis characterized by diarrhea. Clinical symptoms, histopathological changes in the small intestine, and the detection of rotavirus antigen in enterocytes were all characteristic of rotavirus-induced gastroenteritis. Using this small animal model, passive protection of suckling mice against human rotavirus infection was achieved with the use of immunoglobulin (IgY) from the yolks of eggs of rotavirus-immunized hens. When IgY against a rotavirus strain homotypic to the challenge virus (MO strain) was administered in the mice, complete protection against rotavirus infection was achieved. On the other hand, with oral administration of IgY against a heterotypic strain (serotype 1, Wa strain), a lower protective effect was nevertheless obtained. The four different strains of human rotavirus (Wa, KUN, MO, and ST3) were inactivated in vitro by treatment with PSK, a protein-bound polysaccharide preparation, in a dose-dependent manner. Oral administration of 2.5 mg of PSK caused a therapeutic effect on experimentally MO-infected suckling mice. The antiviral effect of PSK was indicated by the reduction of the duration of diarrhea.

Animals↗
PubMed1990

Comparative evaluation of two test methods (enzyme immunoassay and latex fixation) for the detection of heterophil antibodies in infectious mononucleosis.

The present study evaluated the Ventrescreen Mono enzyme immunoassay (Ventrex Laboratories) and Monolatex (Wampole Laboratories) for detection of infectious mononucleosis-specific heterophil antibodies by comparing test results on sera of 247 symptomatic patients. The purpose of this study was to compare not only the two different test systems but also the two different methods they represent for accuracy in detecting infectious mononucleosis-specific heterophil antibodies. Discrepancies in the test results of the two kits were arbitrated by determining the Epstein-Barr virus antibody profiles of the samples. The study showed that the Ventrescreen Mono enzyme immunoassay is as good as the Monolatex test for detecting heterophil antibodies. After discrepancies were resolved, the sensitivity and specificity of the Ventrescreen assay were 100 and 98%, respectively.

Adolescent↗
PubMed1990

A novel isolation method for hen egg yolk antibody, "IgY".

A method for isolation of egg yolk immunoglobulin, IgG, a livetin protein, was investigated. Several natural gums (carrageenan and xanthan gum) were found to be effective for removal of yolk lipoprotein as a precipitate. The effect was pronounced with lambda-carrageenan and the lipid content in the supernatant after removal of the resulting precipitate was less than 0.4% of that of egg yolk. IgY remained in this supernatant, with a yield of 86%, and was isolated by chromatography on a column of DEAE-Sephacel followed by salting-out with sodium sulfate. IgY thus isolated was almost pure (98%) and the yield was 70 to 100 mg per egg.

Animals↗
PubMed1989

Forward-masking properties of multicomponent signals in normal and hearing-impaired subjects.

The forward-masking properties of inharmonic complex stimuli were measured both for normal and hearing-impaired subjects. The signal threshold for a 1000-Hz pure-tone probe was obtained for six different maskers, which varied in the number of pure-tone components. The masking stimuli consisted of 1, 3, 5, 7, 9, or 11 components, logarithmically spaced in frequency surrounding the signal and presented at a fixed level of 80 dB SPL per component. In most normal-hearing subjects, the threshold for the probe decreased as the number of masking components was increased, demonstrating that stimuli with more components tended to be less effective maskers. Results from hearing-impaired subjects showed no decrease in threshold with increasing number of masking components. Instead, the thresholds increased as more components were added to the first masker. These results appear to be consistent with suppression effects within the multicomponent maskers for the normal subjects and a lack of suppression effects for the hearing-impaired subjects. The results from the normal-hearing subjects are also consistent with "across-channel" cuing.

Adult↗
PubMed1989

Histopathological evaluation of rotation sutures for involutional entropion.

Rotation sutures are a popular method of temporarily correcting involutional entropion. The permanence of the procedure depends on a fibrotic scar along the suture tracks. Sutures which create generous scars would probably produce the most satisfactory results. In this study 4-0 chromic gut, nylon, and silk sutures were evaluated in rabbit lower eyelids for their ability to create histologically demonstrable fibrous tracks. All three sutures incited inflammatory cells and fibroblastic activity with collagen formation at two and four weeks. Residual scar tracks were observed at six weeks (two weeks after suture removal) also. Human specimens showed similar types of scar formation from the sutures. It was apparent that all three sutures create fibrotic scars along their tracks sufficient to correct, at least temporarily, involutional entropion.

Animals↗
PubMed1989

[Studies on the constituents of Leucoseptrum stellipillum].

Flavonoids, triterpenoids, and steroids were isolated from the leaves of Leucoseptrum stellipillum (MIQ). Kitamura et Murata and identified as apigenin, luteolin, chrysoeriol, ursolic acid, pomolic acid, tormentic acid, beta-sitosterol, and beta-sitosterol glucoside by comparison of their spectral data with those of authentic specimens. Among these compounds, the triterpenoids showed significant antibacterial activities against Streptococcus mutans.

Bacteria↗
PubMed1988

Lytic anti-endothelial cell antibodies in haemolytic-uraemic syndrome.

Sera from 13 of 14 children with acute haemolytic uraemic syndrome (HUS) contained complement-fixing IgG and IgM antibodies that lysed cultured human umbilical vein endothelial cells. In 3 of 3 sera tested, no lysis of dermal fibroblasts was observed. The endothelial cell antigen was lost after treatment of the cells with gamma interferon. In contrast, only 3 of 5 adult patients with acute, non-relapsing, thrombotic thrombocytopenic purpura (TTP) had lytic anti-endothelial antibodies and only 1 of these recognised an antigen lost upon gamma interferon treatment. None of 32 control sera contained lytic anti-endothelial cell antibodies. These data suggest that HUS involves a disorder of immunoregulation and that a unique class of anti-endothelial cell antibodies is produced that may take part in the pathogenesis of vascular injury in HUS.

Adult↗
PubMed1988

Chronic ethanol causes heterologous desensitization of receptors by reducing alpha s messenger RNA.

One of the biochemical results of ethanol exposure is a change in the amount of the intracellular second messenger cyclic AMP (cAMP) produced in response to receptor stimulation. In general, acute ethanol exposure increases the amount of cAMP produced on stimulation of receptors coupled to the enzyme adenylyl cyclase via the GTP-binding protein Gs, whereas chronic ethanol exposure has the opposite effect (results for receptors coupled via Gi have been more variable). We previously reported that adaptation to continuous ethanol exposure reduces receptor-stimulated cAMP production by 25-35% in a neuroblastoma cell line (NG108-15), and an even greater reduction of 75% was observed in lymphocytes taken from actively-drinking alcoholics. This reduction in receptor-stimulated cAMP levels was recently confirmed in platelets from alcoholics. None of these studies, however, determined whether more than one receptor coupled to adenylyl cyclase activity was affected in the same cell. Here we report that chronic ethanol exposure causes desensitization of heterologous receptors coupled to Gs as cAMP production mediated by prostaglandin E1 as well as by adenosine is reduced by approximately 30% in NG108-15 cells. We show that, after chronic ethanol exposure, the activity of the alpha subunit of Gs is decreased by 29%, the amount of alpha s protein is decreased by 38.5%, and alpha s messenger RNA is decreased by 30%. Thus, cellular adaptation to ethanol involves a reduction in alpha s mRNA and, as a consequence, reduced cAMP production by heterologous receptors coupled to Gs. Such changes in cAMP production may account for the tolerance and physical dependence on ethanol in alcoholism.

Cyclic AMP↗