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Biomedical subjects

K Kim

Publications and source records attributed to K Kim.

At least 415 records · Page 23Linked to original sources
PubMed1994

Analysis of repeated categorical data using generalized estimating equations.

Moment methods for analysing repeated binary responses have been proposed by Liang and Zeger, and extended by Prentice and Zhao and Prentice. In these estimating equations, models are proposed for the correlation between the repeated binary responses. We extend Liang and Zeger's method to models for the correlation between repeated nominal or ordinal categorical responses; in particular, when the repeated responses are binary, our methods reduce to Liang and Zeger's method. Our method is illustrated with two datasets. One dataset contains repeated observations of self-assessment of arthritis, an ordered variable with three categories, collected during a randomized comparative study of alternative treatments of patients with rheumatoid arthritis. The second dataset is a longitudinal study of the health effects of air pollution, in which the repeated ordered multinomial response is the wheezing status (no wheeze, wheeze with cold, wheeze apart from cold) of a child at ages 9, 10, 11 and 12 years.

Adult↗
PubMed1994

Presence of gonadotropin-releasing hormone mRNA in the rat olfactory piriform cortex.

Gonadotropin releasing hormone (GnRH) neurons are known to be originated from the olfactory placode and to enter the forebrain regions during embryonic development. The present study aims to ascertain whether GnRH is locally expressed in the olfactory cortex. Northern blot hybridization and reverse transcription-polymerase chain reaction revealed that GnRH mRNA was present in the rat olfactory cortex as well as in the olfactory bulb. The predicted size of GnRH mRNA is similar to that detected in the hypothalamus. In situ hybridization histochemistry also showed that GnRH mRNA is highly concentrated in the olfactory piriform cortex. The present data indicate that GnRH is synthesized in the olfactory piriform cortex.

Animals↗
PubMed1994

Inhibition of metal-catalyzed oxidation systems by a yeast protector protein in the presence of thioredoxin.

A protector protein from Saccharomyces cerevisiae specifically prevents the inactivation of enzymes caused by a thiol/Fe3+/O2 metal-catalyzed oxidation system but not by an ascorbate/Fe3+/O2 system. Ascorbate/Fe3+/O2-mediated damage of enzymes could be prevented by the protector protein only in the presence of reduced thiol. We demonstrate that two proteins from yeast, thioredoxin plus another protein having properties similar to that expected to thioredoxin reductase, when presented with NADPH and the yeast protector protein prevented inactivation of E. coli glutamine synthetase by the ascorbate/Fe3+/O2 system. This system also removes hydrogen peroxide effectively. We also demonstrate evidence suggesting that the NADPH-dependent thioredoxin system reactivates protector protein by reversible disulfide-dithiols exchange.

Amino Acid Sequence↗
PubMed1994

DNA-protein cooperativity in the assembly and stabilization of mu strand transfer complex. Relevance of DNA phasing and att site cleavage.

The requirements for negatively supercoiled DNA substrates, the cis-acting transposition enhancer and the Escherichia coli HU protein during the phage Mu transposition reaction are relaxed under DMSO-assay conditions. We have used these modified assay conditions to extend studies on the transposition pathway. We show here that linear DNA fragments containing the right end of Mu (attR) and Mu A protein mutually promote the assembly of "high-order" complexes held together by non-covalent protein-DNA and protein-protein interactions. A large subset of these complexes is competent in mediating strand transfer. DNA fragments containing the left end of Mu (attL) as well as non-Mu DNA can be used as targets during strand transfer. The R1 and R2 subsites within attR are required, but R3 is dispensable, in the protein-DNA oligomerization steps as well as in the strand transfer reaction. Proper phasing and spacing between R1 and R2 are central to the reaction. A single base-pair change in the terminal nucleotide that renders attR non-cleavable prevents the assembly of stable high-order complexes, showing that strand cleavage and stabilization of high-order complexes are tightly coupled events. Conversely, pre-cleavage at the attL site allows it to function in the assembly process, albeit at a much lower efficiency than attR. In the presence of HU, the reactivity of pre-cleaved attL is enhanced significantly.

Attachment Sites, Microbiological↗
PubMed1994

Cross-talk between N-methyl-D-aspartate and adrenergic neurotransmission in the regulation of hypothalamic GnRH gene expression.

Although it has been known that activation of N-methyl-D-aspartate (NMDA) receptor effectively stimulates GnRH biosynthesis and release from the rat hypothalamus, no evidence that NMDA receptors exist in GnRH neurons is yet available. It is then presumed that the action of NMDA on GnRH neurons may be indirectly mediated through interneurons, such as catecholamines. The present study is designed to investigate whether the effect of NMDA on GnRH gene expression is mediated by adrenergic neuronal system. Adrenergic receptor antagonists were administered 30 min prior to NMDA administration to immature male rats and then animals sacrificed 60 min after NMDA administration. GnRH mRNA levels were determined by Northern blot analysis using a GnRH RNA probe. Inhibition of either alpha 1 adrenergic receptor with prazosin or beta adrenergic receptor with propranolol did not cause any change in the basal GnRH mRNA levels but reduced NMDA-induced GnRH mRNA levels. However, inhibition of alpha 2 adrenergic receptor with yohimbine increased GnRH mRNA levels but did not affect NMDA-induced GnRH mRNA levels. These findings suggest that the effect of NMDA on GnRH gene expression is mediated through adrenergic neurotransmission.

Animals↗
PubMed1994

Purification and characterization of thiol-specific antioxidant protein from human red blood cell: a new type of antioxidant protein.

A thiol-specific antioxidant protein (Protector Protein, PRP) was purified from human red blood cells (RBC). The PRP exists as a predominant protein in human RBC, which showed distinct thiol-specific antioxidant activities in the presence of dithiothreitol (DTT) as a reducing equivalent. The human RBC PRP (HRPRP) completely inhibited visible absorption spectral changes of oxyhemoglobin, DNA cleavage, and the peroxidation of RBC membrane by a nonenzymatic Fe3+/O2/thiol mixed-function oxidation system capable of generating hydroxyl radical. These observations suggest that HRPRP could act as a new type of antioxidant protein to maintain the RBC integrity by scavenging reactive oxygen species.

Antioxidants↗
PubMed1994

Pancreatic cancer. Cytologic study of peritoneal washings.

OBJECTIVE: To delineate the frequency and significance of free cancer cells in the peritoneal cavity of patients with pancreatic exocrine adenocarcinoma. DESIGN: Randomly selected patients with pancreatic cancer had peritoneal washings performed at the beginning and conclusion of laparotomy. Results of cytologic studies were correlated with the clinical findings, size, spread, and resectability of the tumor and with the survival time of the patient. All patients were followed up until the present or until their deaths. SETTING: Tertiary care, referral hospitals in Toledo, Ohio. PATIENTS: Only patients with biopsy-proven adenocarcinoma of the pancreas were included. Thirty-six patients, yielding 62 specimens for cytologic study, were included. INTERVENTION: Peritoneal washings were performed at the beginning and completion of laparotomy. Each washing was evaluated independently by two skilled cytologists. If present, ascites was quantitated and studied cytologically. Biopsy specimens were obtained in each patient at the time of the study. MAIN OUTCOME MEASUREMENTS: Presence or absence of malignant cells in peritoneal fluid; maximal diameter, grade, and spread of cancer; presence and volume of ascitic fluid; resectability of cancer; and length of survival of the patient. RESULT: Of the 36 patients studied, three had positive cytologic findings. All three had peritoneal carcinomatosis. Of 11 patients with ascites, only one had positive cytologic findings. CONCLUSIONS: Results of cytologic studies of peritoneal washings or of ascitic fluid are seldom positive with pancreatic exocrine carcinoma. When positive, they denote a very grave prognosis.

Adenocarcinoma↗
PubMed1994

Personal history, training, and worksite as predictors of back pain of nurses.

Back pain among nurses is a common problem. Prior studies of this problem have been based on cross-sectional or retrospective data. This 18-month prospective study involving nurses newly graduated from nursing school investigated personal, worksite, and training factors associated with future risk of back pain. Each nurse underwent a preliminary interview and periodic follow-ups to identify those with back injuries. Contingency tables and logistic regression analyses demonstrated that prior significant back pain episodes (evidenced by previous job changes because of back pain, frequent medication use, etc.) were associated with increased future risk. Training at nursing school or on the job did not have a protective effect. This pilot study therefore suggests factors useful in placement and counseling of new nurses and indicates the need for further implementation of mechanical lift assist device use.

Accidents, Occupational↗
PubMed1994

Primary directional coronary atherectomy for acute myocardial infarction.

The effectiveness of primary coronary angioplasty for acute myocardial infarction (AMI) is now widely recognized. However, the reocclusion rate is as high as 10%. Directional coronary atherectomy (DCA), now used widely in the treatment of stable and unstable angina pectoris, has not been recommended as the primary reperfusion therapy for AMI. This report describes the first preliminary study of primary DCA for AMI without any antecedent thrombolytic therapy or balloon coronary angioplasty. Five patients received primary DCA. The initial results were very good, but further study is necessary to determine the efficacy, particularly the long-term results, of primary DCA in the treatment of AMI.

Atherectomy, Coronary↗
PubMed1994

Acute myocardial infarction in a young adult due to solitary giant cell arteritis of the coronary artery diagnosed antemortemly by primary directional coronary atherectomy.

It has been reported sporadically that several types of coronary arteritis can result in myocardial infarction. Recently, we treated a 27-year-old with acute anterior myocardial infarction. Primary directional coronary atherectomy was performed in order to recanalize the totally occluded coronary artery. The atherectomized tissue consisted of thrombi and intima infiltrated with inflammatory cells and multinucleated giant cells. Underlying diseases which can result in giant cell arteritis were excluded. This report documents that coronary arteritis can induce acute myocardial infarction, and that directional coronary atherectomy can be an effective tool in the diagnostic method for coronary arteritis.

Adult↗
PubMed1994

Analysis of thymidine kinase gene expression in preimplantation mouse embryos.

Thymidine kinase (TK) activity was examined during the development of preimplantation mouse embryos. TK activity was increased approximately 20-fold from day 2 embryos (2-cell) to day 5 embryos (late blastocyst). TK activity did not change along with the progression into S-phase of the first and the second cell cycles but increased sharply at S-phase of the third cell cycle. Analysis of TK mRNA with a reverse transcription-polymerase chain reaction (RT-PCR) method showed that the level of TK mRNA was low in ovulated eggs and 1-cell embryos and was hardly detectable in day 2 embryos (2-cell), but sharply increased in day 3 embryos (mixture of 5- to 8-cell and morula). The functional role of 5'-flanking sequence of TK gene was also investigated in preimplantation embryos after microinjection with the DNA construct of 5'-flanking sequence of TK (2.4 kb) linked to bacterial lacZ gene (TK2.5lacZ) into the pronucleus of 1-cell and subsequently by histochemical staining with X-gal. beta-Galactosidase activity was first detected in day 3 embryos (8-cell), and 30% of embryos were stained with X-gal in day 4 and day 5 embryos, respectively. These results show that an increase in TK activity occurred after 2-cell stage, and this increase was primarily due to the embryonic activation of TK gene expression. Also, it appears that the 5'-flanking sequence of TK may directly regulate the TK gene expression at the transcriptional level during preimplantation murine development.

Animals↗
PubMed1994

Cloning of a new allelic variant of a Saccharomyces diastaticus glucoamylase gene and its introduction into industrial yeasts.

A new allelic variant of the STA2 gene, designated as STA2K, coding for a secreted glucoamylase, was cloned. Differences were revealed both in the structural gene and in the promoter region, as compared to other STA genes. The most peculiar structural features of STA2K are 1. a 1.1-kb natural deletion in its promoter located 189 nucleotides upstream of the translation start codon; and 2. an Asn-->Asp single amino acid change within the putative active site of the encoded glucoamylase. Neither the presence of glucose in the medium nor the host cell's mating type constellation affected the expression level of STA2K in S. cerevisiae. Self-replicating yeast plasmids containing STA2K were constructed and used to transform a laboratory yeast strain and various brewing strains. Pilot brewing tests with glucoamylase-secreting transformants of a brewing strain produced superattenuated beers at accelerated fermentation rates.

Alleles↗
PubMed1994

Dissociation and complexation of fluoroquinolone analogues.

The dissociation and the complexation behaviours of four fluoroquinolone antibiotics have been studied. The acid dissociation constants of ciprofloxacin, enoxacin, norfloxacin and ofloxacin were determined by conventional potentiometric and conductometric techniques. Increasing the Hammett substituent constant, the pKa values were decreased. The absorption of fluoroquinolones in the intestinal tract are probably transported by pH-dependent mechanisms. Formation constants of the iron(III) complexes (1:1) of the fluoroquinolone analogues were determined by spectrophotometry. The optimum pH for complexation was 3.80.

Anti-Infective Agents↗
PubMed1994

Effect of glutathione and its related enzymes on chemosensitivity of renal cell carcinoma and bladder carcinoma cell lines.

Glutathione and glutathione-related enzymes have been implicated in sensitivity of tumors to chemotherapeutic drugs. In the present study, glutathione and the activity of its related enzymes were quantitated in 4 renal cell carcinoma cell lines and 4 bladder carcinoma cell lines. The expression of glutathione-s-transferase pi and alpha in each cell line was analyzed by immunoblot analysis. The relationships between glutathione levels, glutathione peroxidase activity and glutathione-s-transferase activity and tumor sensitivity to cisplatinum, doxorubicin and vinblastine were determined by linear regression analysis. Glutathione levels were positively related to cisplatinum resistance in both renal cell carcinoma and bladder carcinoma cell lines and to doxorubicin resistance in bladder carcinoma cell lines. A positive correlation between glutathione peroxidase activity and doxorubicin resistance was identified in renal cell carcinoma cell lines, but no correlation was noted in bladder carcinoma cell lines. No significant correlation was apparent between glutathione-s-transferase activity and sensitivity to any of the drugs tested in this study. To further clarify the relationship between glutathione levels and the cytotoxicity of the drugs, we evaluated the effect of glutathione depletion by L-buthionine sulfoximine on the cytotoxicity of the drugs in bladder carcinoma cell lines. Glutathione depletion enhanced cisplatinum cytotoxicity 1.3- to 1.7-fold and doxorubicin cytotoxicity by 1.45- to 11.2-fold. Glutathione depletion did not change vinblastine cytotoxicity. The present study demonstrates that glutathione and its related enzymes affect sensitivity to cisplatinum or doxorubicin. The drug resistance mechanism elicited by glutathione and its related enzymes in these tumors needs further elucidation so that chemotherapeutic regimens may be modified.

Carcinoma, Renal Cell↗
PubMed1994

Attention/likelihood theory: reply to Hintzman (1994).

D. L. Hintzman's (1994) criticism of our theory on recognition memory consists of 2 points: An equation of attention/likelihood theory has been incorrectly written and the likelihood ratios of the theory can be replaced by another, preferable transformation. Both of these points are discussed and rebutted.

Attention↗
PubMed1994

Facilitating prelinguistic communication skills in young children with developmental delay. II: Systematic replication and extension.

Four children with mental retardation were studied in the context of a multiple baseline across subjects design. Staff members used a modified version of the milieu teaching method to facilitate intentional requesting. The results replicated the finding that a modified version of milieu teaching was effective in facilitating the use of intentional requesting by children with developmental delays in an intervention context (Warren, Yoder, Gazdag, Kim, & Jones, 1993). This study also extended the Warren et al. (1993) work by (a) documenting that increased intentional requesting generalized to sessions with the children's mothers, (b) demonstrating that mothers who were naive to the purposes of the study were more likely to linguistically map their children's prelinguistic communication after the intervention than before the treatment, and (c) that mothers and teachers who were naive to the purposes of the study linguistically mapped the children's intentional communication more than the children's preintentional communication. We discuss implications of these results for early intervention, the transactional theory of development, and the importance of the distinction between intentional versus preintentional communication.

Adult↗