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Biomedical subjects

K Kim

Publications and source records attributed to K Kim.

At least 577 records · Page 32Linked to original sources
PubMed1986

Mediastinal teratoma associated with Klinefelter's syndrome.

The clinical and autopsy findings in a case of histologically benign teratoma of the mediastinum in a 19-year-old man with Klinefelter's syndrome are presented. A rough statistical analysis based on a review of the literature revealed that the incidence rate of Klinefelter's syndrome among the patients with mediastinal germ cell tumor is 30 to 40 times that of Klinefelter's syndrome among the general control population. The pathogenesis of this neoplasm appears to be related to the genetic abnormality in Klinefelter's syndrome, and this seems to predispose to the development of extragonadal mediastinal germ cell neoplasms.

Adult↗
PubMed1985

Nonenzymatic cleavage of proteins by reactive oxygen species generated by dithiothreitol and iron.

Many enzymes, represented by yeast glutamine synthetase, are inactivated and degraded in the presence of dithiothreitol (DTT), oxygen, and catalytic amounts of iron salts. The roles of DTT and iron can be replaced by ascorbate and copper, respectively. Experimental data suggest that reactive oxygen species, likely hydroxyl radicals, are generated locally around irons bound at specific sites on enzymes, and these species are responsible for the inactivation and degradation. Since many biochemicals are contaminated with metal salts in quantities sufficient for some hydroxyl radical formation to occur, the possibility of oxidative modification and degradation should be considered when an enzyme is exposed to DTT.

Amino Acids↗
PubMed1985

Copy number of the broad host-range plasmid R1162 is determined by the amounts of essential plasmid-encoded proteins.

DNA of the broad host-range plasmid R1162 contains a 1700 base-pair segment essential for plasmid maintenance. This region, RepI, consists of two cotranscribed genes encoding polypeptides with molecular weights of 29,000 and 31,000. Fusion of RepI to the strong tac promoter results in greatly increased amounts of at least one of these polypeptides. In trans, this construction has two other properties: it can raise the copy number of R1162, and it can protect this plasmid from loss due to incompatibility. Both effects require intact RepI genes. These properties of the RepI region, along with those of an origin-linked region described earlier, are discussed with respect to current models for control of plasmid copy number.

Adenosine Triphosphatases↗
PubMed1985

Dibutyryl cyclic adenosine monophosphate stimulates in vitro luteinizing hormone-releasing hormone release only from median eminence derived from ovariectomized, estradiol-primed rats.

The present study examined the effect of intermittent infusion of dibutyryl cyclic AMP (dbcAMP; 10(-7) M; 10 min on, 20 min off) on in vitro luteinizing hormone-releasing hormone (LH-RH) release from the rat median eminence (ME) derived from immature rats: intact females, intact males, ovariectomized (OVX) females, castrated (CAST) males, ovariectomized, estradiol primed (OVX + E2) females and castrated, estradiol primed (CAST + E2) males. In intact, OVX and CAST conditions, spontaneous LH-RH release from MEs was not modified by dbcAMP infusion. However, E2 implants in OVX and CAST rats selectively affected the responsiveness of MEs to dbcAMP: ME from OVX + E2 were highly responsive to dbcAMP; contrarily, MEs from CAST + E2 were unresponsive to this nucleotide. Therefore, these differences in MEs responsiveness to dbcAMP-induced LH-RH release appear to be dependent upon a critical effect of E2 priming on this tissue in female but not in male rats.

Animals↗
PubMed1985

In vitro luteinizing hormone-releasing hormone release from superfused rat hypothalami: site of action of progesterone and effect of estrogen priming.

The study examined the effect of estrogen priming on progesterone (P4)-induced LHRH release, the tissue site of action of P4, and the effect of 5 alpha-dihydroxyprogesterone (5 alpha-DHP) on LHRH release from hypothalamic fragments superfused in vitro. Immature female rats were ovariectomized (OVX) and, at 28 days of age, Silastic capsules containing estradiol (E2) were implanted. Two days later, animals were killed and hypothalamic fragments were removed and transferred to superfusion chambers. The hypothalamic units received P4 or 5 alpha-DHP delivered in an intermittent mode (10-min on, 20-min off). LHRH was determined in perfusates by RIA. After the input characteristics of different infusion modes (single pulses, intermittent, and continuous) of P4 infused into superfusion chambers were assessed, an intermittent infusion mode (10-min on, 20-min off) was selected for further examinations. In the mediobasal hypothalamic-anterior hypothalamic-preoptic area (MBH-AHA-POA) tissue preparations, we observed: 1) an infusion of 5 alpha-DHP was ineffective in stimulating LHRH release; 2) the release pattern of LHRH in response to three different P4 doses (10, 20, and 50 ng/ml) was similar in terms of percent changes (202% to 219% over control values); and 3) E2 priming was absolutely required for P4-stimulated LHRH release, and this requirement appeared to be dose dependent. Upon an examination of three hypothalamic tissue boundaries [the MBH, the POA-suprachiasmatic nuclei (POA-SCN), and the median eminence (ME)] to better delineate the in vitro site of action of P4 on LHRH release, it was demonstrated that the MBH responded upon P4 infusion, whereas the POA-SCN was unable to do so. The ME also responded upon P4 infusion, and LHRH release followed closely the pulsatile administration of P4 since upon each challenge of the steroid at the concentration of 10 or 20 ng/ml, a significant rise in LHRH release occurred. However, the temporal patterns of LHRH release from the ME appears to be different from those obtained from the MBH as well as the MBH-AHA-POA. These observations demonstrate that an intermittent infusion of P4, but not 5 alpha-DHP, is effective in activating the neural LHRH apparatus. Estrogen is an obligatory requirement for this P4-stimulated LHRH release, and the neural site of action of P4 resides within the MBH. However, this steroid also can act directly upon the ME nerve terminals to release LHRH.

Algestone↗
PubMed1985

Severe Kawasaki heart disease treated with an internal mammary artery graft in pediatric patients. A first successful report.

Two Japanese boys, 6 and 10 years old, required operation for severe Kawasaki heart disease. Both had multiple coronary arterial aneurysms and stenoses, and one had mitral regurgitation as well. The operations consisted of anastomosis between the left internal mammary artery and the left anterior descending artery and insertion of an autologous saphenous vein between the aorta and the posterior descending artery in both patients. The mitral valve was replaced in the one with mitral regurgitation. Angina pectoris has been completely relieved as confirmed by postoperative angiocardiography. Late results of coronary bypass grafting with the saphenous vein in pediatric patients with Kawasaki disease have been less than satisfactory because of the high occlusion rate of the graft. The internal mammary artery may be superior, at least theoretically, to the saphenous vein graft because it is a "living graft" with a high possibility of growing and with less susceptibility to degeneration. This is the first report of successful operation utilizing an internal mammary artery graft in coronary bypass for Kawasaki disease.

Aneurysm↗
PubMed1985

[Evaluation of the effectiveness and safety in the use of cold-diltiazem-potassium cardioplegia in coronary artery bypass surgery: a first clinical trial].

The effectiveness and safety of diltiazem (DIL), a slow channel calcium blocker, added in cold potassium cardioplegic (CP) solution was evaluated in coronary artery bypass graft (CABG) surgery for 2 purposes; (1) protection of ischemic myocardium during cardiac arrest and (2) prevention of perioperative coronary artery spasm (PCS). Diltiazem of 15 mg was added to a liter of CP which was administered 10 ml/kg B.W. initially and 5mg/kg thereafter. The serum concentration of DIL was 570 ng/ml at the time of aortic declamping, 210 ng/ml at cardioversion and 150 ng/ml one hour after surgery. The left ventricular stroke work index was increased significantly (p less than 0.05) in patients treated by DIL-CP, compared with the patients treated by regular CP without DIL. However, CPK-MB values were not significantly different in either group. The incidence of PCS has decreased from 9.1% to 0.8% (p less than 0.01) after the use of DIL-CP. Perioperative myocardial infarction rate has also decreased from 5.5% to 1.6%. No major or long-lasting side-effects were encountered. We consider that DIL-CP is a safe and excellent CP in CABG surgery and we are now utilizing this CP in all patients requiring CABG surgery.

Adult↗
PubMed1984

Idiopathic aldosteronism. A possible disease of the intermediate lobe of the pituitary.

A 37-year-old woman with documented primary aldosteronism died of a cerebral hemorrhage. At postmortem examination she was found to have bilateral, adrenal hyperplasia and nodular basophilic hyperplasia of the anterior and intermediate lobe of the pituitary. Based on these findings and experimental evidence suggesting the existence of a pituitary factor that stimulates aldosterone secretion, we postulate that idiopathic aldosteronism is caused by an abnormality of the intermediate lobe of the pituitary gland leading to overproduction of non-adrenocorticotropic hormone peptides derived from pro-opiomelanocortin that increase aldosterone production and cause hyperplasia of the adrenal glands.

Adrenal Glands↗