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Biomedical subjects

K Kim

Publications and source records attributed to K Kim.

At least 397 records · Page 22Linked to original sources
PubMed1995

Papillary cystic and solid tumors of the pancreas: a pancreatic embryonic tumor? Studies of three cases and cumulative review of the world's literature.

BACKGROUND: The papillary cystic and solid tumor of the pancreas is rare. It occurs predominantly in young women, and most present a benign behavior. The pathogenesis of this tumor has attracted a number of investigations but remains unclear. METHODS: We present three patients with this tumor and a review of 289 others from the world's literature, a total of 292 cases. On the basis of the analyses of the clinical and pathologic features from the reported cases, the pathogenesis of this unusual tumor has been further explored. RESULTS: Ninety percent of the patients were female, with a mean age of 23.9 years. The tumors were usually quite large with a mean diameter of 10.3 cm. Ninety-two percent of these tumors were totally or partially cystic. Rupture of the capsule resulted in hemoperitoneum in eight cases, five of which were without any identifiable cause. Forty-three tumors (14.7%) have been recognized as malignant. The overall prognosis has been excellent and an aggressive approach to resection is indicated. CONCLUSIONS: The results of immunohistochemical staining and electromicroscopy were rather diverse, but most, including the current cases, support the hypothesis that the tumor originates from pleuripotential embryonic stem cells. Thus the term pancreatic embryonic tumors seems preferable to papillary cystic and solid tumor of the pancreas to delineate the origin of the tumor and to reflect some of its biologic characteristics.

Adolescent↗
PubMed1995

Intralist interference in recognition memory.

Three experiments on recognition memory were carried out to define the nature of intralist interference effects. Experiment 1 replicated the findings of an earlier study (A. I. Schulman, 1971) on what appeared to be combined study (input) and test (output) order effects and added information on the presence of speed-accuracy trade-off effects. Experiment 2 demonstrated that only test order was effective and that study order effects did not occur. Experiment 3 demonstrated again that only test order was effective and also showed that the effect remained when response times were controlled. Attention/likelihood theory was fitted to the data of the final, clarified interference effect.

Adult↗
PubMed1995

Rapid diagnosis of pulmonary tuberculosis by using Roche AMPLICOR Mycobacterium tuberculosis PCR test.

A rapid PCR-based test for the diagnosis of pulmonary tuberculosis, the Roche AMPLICOR Mycobacterium tuberculosis test (AMPLICOR MTB), was evaluated. Results from AMPLICOR MTB were compared with culture results and the final clinical diagnosis for each patient. A total of 985 specimens from 372 patients were tested. When AMPLICOR MTB results were compared with resolved results, i.e., a specimen grew M. tuberculosis or was obtained from a patient with a clinical diagnosis of tuberculosis, the sensitivity, specificity, positive predictive value, and negative predictive value for the AMPLICOR MTB test were 66.7, 99.6, 91.7, and 97.7%, respectively. These results were comparable to those obtained from culture. Test results were available approximately 6.5 h after specimen receipt in the laboratory. Our data demonstrate that AMPLICOR MTB will provide rapid, valuable information for the diagnosis and control of tuberculosis.

Bacteriological Techniques↗
PubMed1995

Acute increase of GABAergic neurotransmission exerts a stimulatory effect on GnRH gene expression in the preoptic/anterior hypothalamic area of ovariectomized, estrogen- and progesterone-treated adult female rats.

Although gamma-aminobutyric acid (GABA) is known to play an important role in the regulation of GnRH release from the hypothalamus, GABAergic action on hypothalamic GnRH gene expression is poorly understood. The present study aims to evaluate the effects of several GABAergic compounds on GnRH mRNA and serum LH levels at the times of LH surge induced by estrogen plus progesterone treatment in long-term ovariectomized adult rats. Animals received either aminooxyacetic acid (AOAA, an inhibitor of GABA catabolism, i.p.), muscimol (GABA-A type agonist, i.c.v.) or baclofen (GABA-B type agonist, i.c.v.) 2 h prior to sacrifice. GnRH mRNA in the preoptic/anterior hypothalamic area and serum LH levels were determined by Northern blot analysis and LH radioimmunoassay, respectively. All of three GABA mimetics blocked the LH surge induced by estrogen plus progesterone in a dose-dependent manner. However, inhibition of GABA catabolism with AOAA in a dose range of 10-100 mg/kg b.w. increased GnRH mRNA level by 30%. Activation of GABA-A receptor with muscimol at a low dose (5 nmol) but not at high doses (10 and 30 nmol) elevated GnRH mRNA levels by 60% over the control value. Activation of GABA-B receptor with baclofen augmented GnRH mRNA levels in a dose-dependent manner. These observations indicate that acute increase of GABAergic neurotransmission may differentially regulate the release and GnRH gene expression depending on its receptor subtypes.

Aminooxyacetic Acid↗
PubMed1995

Activation of central GABAA-but not of GABAB-receptors rapidly reduces pituitary LH release and GnRH gene expression in the preoptic/anterior hypothalamic area of ovariectomized rats.

gamma-Aminobutyric acid (GABA) exerts an inhibitory action on gonadotropin-releasing hormone (GnRH) release from the hypothalamus. In vivo, this inhibitory action appears to be mediated via the GABAA receptor since in ovariectomized (ovx) rats and sheep direct application of muscimol (MUS), a GABAA agonist, into the preoptic area (POA), the site were the GnRH cell bodies are located, caused an immediate reduction of LH release. This effect may be the result of an inhibition of GnRH release but also GnRH biosynthesis may be affected. Using competitive reverse transcription-polymerase chain reaction (RT-PCR) we now addressed the question, whether an acute inhibition of the GnRH pulse generator in ovx rats by GABA involves reduction of GnRH biosynthesis as determined by GnRH mRNA levels in micropunches of the POA. To activate either the GABAA or GABAB receptor, we injected intraventricularly (icv) MUS or baclofen (BAC). Intracerebroventricular injection of 10 nmol MUS caused a rapid and lasting inhibition of LH release from about 7.5 ng/ml (pretreatment value) to approximately 1.5 ng/ml. Neither application of BAC or saline (control injections) affected LH secretion. Two hours after icv injections, rats were decapitated and GnRH mRNA levels were determined. MUS induced a pronounced decrease of GnRH levels in the POA (control rats: 2.26 pg GnRH mRNA; MUS-treated rats: 0.85 pg, n = 10/group). BAC was without any effect on GnRH mRNA levels. Thus, we confirm the inhibitory action of GABA on LH release in vivo which is exerted via the A-subtype of the receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effect of GABAergic compounds on gonadotropin-releasing hormone receptor gene expression in the rat.

Using a competitive reverse transcription-polymerase chain reaction (RT-PCR), the amounts of GnRH receptor (GnRHR) transcript in a discrete nucleus micropunched from rat brain slices were determined. GnRHR transcript was highly expressed in anterior pituitary >> median eminence > posterior mediobasal hypothalamus (pMBH) > preoptic area (POA) but not in cortex and posterior pituitary, which were used as control tissues. To examine the effect of GABA on GnRHR transcript level, 10 nmol of muscimol, a GABA-A receptor agonist, or baclofen, a GABA-B receptor agonist, was microinjected into the lateral ventricle of ovariectomized rats. Two hours after an intraventricular injection, rats were decapitated. Blood was collected 1 h before and after drug administration and used for LH determination. Serum LH levels were significantly reduced by muscimol but not by baclofen within 2 h. The activation of GABA-A receptors with muscimol resulted in a significant inhibition in GnRHR transcript level in both the pMBH and POA but not in the pituitary. The activation of GABA-B receptors with baclofen, however, did not produce any effect on GnRHR transcript level in the pMBH and POA, as well as the pituitary. This experiment demonstrates for the first time that GABAergic neurotransmission, through GABA-A receptors, is involved in the regulation of GnRHR transcript level in the rat hypothalamus. This suggests that GABAergic neurotransmission regulates GnRHR gene expression in a coordinated, yet complex, fashion in the control of the neuroendocrine function of GnRH-LH axis.

Animals↗
PubMed1995

Cleavage of connectin by calpain and cathepsin D.

mu-Calpain quickly split the alpha-connectin in myofibrils into beta-connectin, and then produced a 1700-kDa component. Cathepsin D also split alpha-connectin into beta-connectin, further degrading it to fragments smaller than the 1700-kDa component with increasing incubation time. The action of cathepsin D on the connectin molecule was distinctly different from that of mu-calpain in terms of the splitting rate and manner. When freshly excised muscle was exposed to a temperature of 37 degrees C, complete disappearance of connectin (alpha, beta and 1700-kDa component) was observed within 36 h. In contrast, at 2 degrees C, about 75% of connectin was retained as beta-form even after 3 weeks. The present data suggest that the degradation of connectin in muscle might be caused by mu-calpain in the early stage of aging, and then with time, this action is replaced by m-calpain or cathepsin D. However, the possibility of other intrinsic proteases participating in the degradation of connectin still remains.

Animals↗
PubMed1995

A 33 kDa Pit-1-like protein binds to the distal region of the human thyrotrophin alpha-subunit gene.

Our previous studies demonstrated that at least two DNA regions with upstream limits between positions -223 to -190 and positions -151 to -135 of the human TSH gene are important for transcriptional regulation by TRH in GH3 rat pituitary cells. The proximal region (-151 to -135 bp) including the cAMP-responsive element (CRE) was required for the induction of the TSH gene by TRH, while the distal region (-223 to -190 bp) containing an element similar to the binding site for the pituitary-specific transcription factor, Pit-1, was necessary to amplify the effects of TRH. To determine whether a pituitary-specific nuclear protein, in addition to the CRE-binding protein, is involved in the molecular mechanism of TRH regulation, a gel retardation assay and Southwestern blot analysis were performed on the distal region with GH3 cell nuclear extracts. GH3 extracts generated a distinct DNA-protein complex that was effectively eliminated in the presence of excess unlabelled DNA fragment, and TRH treatment increased the affinity of protein binding remarkably. Excess Pit-1 DNA-binding sequence from the rat prolactin gene inhibited formation of the complex, but mutation of the Pit-1 consensus sequence in the distal region did not eliminate the complex. In addition, Southwestern experiments showed that a 33 kDa nuclear protein present in GH3 cells bound to this region and its binding affinity was increased slightly 2 h after TRH treatment, with the maximal increase (fivefold) at 3 h, which was similar to the results when using gel retardation. Phosphatase treatment of nuclear protein also resulted in a loss of binding affinity. Taken together, these data indicate that the interaction of a pituitary-specific nuclear protein, identical or closely related to Pit-1, with the distal region may be involved in the TRH stimulation of human TSH gene expression.

Animals↗
PubMed1995

Validity and reliability of a Five Dimensional Life Satisfaction Index.

Validity of the Five Dimensional Life Satisfaction Index (Hawkins, Eklund, Kim, & Greene, 1994), which was developed to measure life satisfaction as it applies to adults with mental retardation, was examined. The index was administered to 48 adults with moderate mental retardation. Results showed (a) alternate forms reliability and internal consistency, (b) convergent and discriminant validity, and (c) construct validity.

Adult↗
PubMed1995

The final stages of spliceosome maturation require Spp2p that can interact with the DEAH box protein Prp2p and promote step 1 of splicing.

Pre-mRNA processing occurs by assembly of splicing factors on the substrate to form the spliceosome followed by two consecutive RNA cleavage-ligation reactions. The Prp2 protein hydrolyzes ATP and is required for the first reaction (Yean SL, Lin RJ, 1991, Mol Cell Biol 11:5571-5577; Kim SH, Smith J, Claude A, Lin RJ, 1992, EMBO J 11:2319-2326). The Saccharomyces cerevisiae SPP2 gene was previously identified as a high-copy suppressor of temperature-sensitive prp2 mutants (Last RL, Maddock JR, Woolford JL Jr, 1987, Genetics 117:619-631). We have characterized the function of Spp2p in vivo and in vitro. Spp2p is an essential protein required for the first RNA cleavage reaction in vivo. Depletion of Spp2p from yeast cells results in accumulation of unspliced pre-mRNAs. A temperature-sensitive spp2-1 mutant accumulates pre-mRNAs in vivo and is unable to undergo the first splicing reaction in vitro. However, spliceosomal complexes are assembled in extracts prepared from the mutant. We show that Spp2p function is required after spliceosome assembly but prior to the first reaction. Spp2p associates with the spliceosome before the first RNA cleavage reaction and is likely to be released from the spliceosome following ATP hydrolysis by Prp2p. The Prp2 and Spp2 proteins are capable of physically interacting with each other. These results suggest that Spp2p interacts with Prp2p in the spliceosome prior to the first cleavage-ligation reaction. Spp2p is the first protein that has been found to interact with a DEAD/H box splicing factor.

Adenosine Triphosphate↗
PubMed1995

Design and analysis of group sequential logrank tests in maximum duration versus information trials.

When monitoring a clinical trial with failure time data using the logrank test and the type I error spending function approach, the information time has to be estimated as a fraction of the maximum number of failures. In maximum duration trials, the denominator of this fraction is a random quantity and has to be estimated; besides, there are two candidates for the denominator, one under the null hypothesis of no treatment difference and the other under the specified alternative hypothesis. Either way, some adjustments are necessary in determining group sequential boundaries in order to maintain type I error at a desired significance level. As a consequence, the type I error spending function will be altered from the one chosen for the design, thus affecting the operating characteristics of the subsequent group sequential logrank tests. In maximum information trials, however, the maximum amount of information is fixed, and thus the estimate of the information time is always unbiased. The net effect is that computation of group sequential boundaries becomes straightforward, with a potential saving in study durations as compared to maximum duration trials. We will illustrate how adjustments are made in maximum duration trials to maintain type I error when the information times are estimated with the information horizons under the null and alternative hypotheses and present numerical explorations to compare robustness of two different estimates of the information times. We then propose a design procedure for maximum information trials and investigate the properties of maximum information trials for different group sequential boundaries. We also compare maximum information trials and maximum duration trials based on an example.

Biometry↗
PubMed1995

The use of FAB mass spectrometry and pyroglutamate aminopeptidase digestion for the structure determination of pyroglutamate in modified peptides.

A new method for the determination of the modified amino acid structures of peptides containing pyroglutamyl residue in their N-terminal position is reported. The combination of fast atom bombardment (FAB) mass spectrometry and pyroglutamate aminopeptidase digestion provides a convenient and sensitive method for the identification of pyroglutamate. In order to investigate the nature of the amino terminal region of the follow post-translationally modified peptides containing pyroglutamyl residues, Neurotensin, Hypertrehalosaemic neuropeptide, and Luteinizing Hormone Releasing Hormone (LH-RH) were digested with pyroglutamate aminopeptidase and analyzed by FAB mass spectrometry. The method provided direct information about the N-terminal structure. The N-terminal pyroglutamates of these peptides are unequivocally determined at a level of 0.9-2.8 nmol per peptide. Several of the complicated procedures and controversies, which accompany the application of traditional methods, are eliminated. We describe the advantages of the combination procedure of FAB mass spectrometry and pyroglutamate aminopeptidase digestion for modified amino acid determination.

Amino Acid Sequence↗
PubMed1995

Prospective analysis of outcome after cardiopulmonary resuscitation in critically ill surgical patients.

BACKGROUND: This study was done to examine the outcome of cardiopulmonary resuscitation (CPR) in the surgical intensive care unit (SICU) and to identify factors preceding cardiopulmonary arrest that could predict survival. STUDY DESIGN: We prospectively collected demographic, laboratory, diagnostic, and complications data in our SICU database on 5,237 consecutive patients and reviewed the charts of all patients receiving CPR. RESULTS: Cardiopulmonary resuscitation was performed upon 1.1 percent (55 of 5,237 patients) of patients in the SICU. Twenty-nine percent (16 of 55 patients) survived greater than 24 hours but died in the hospital, and 13 percent (seven of 55 patients) survived to discharge. No patient with a worsening Glasgow Coma Scale (GCS) score, acute physiology score (APS), or any acute organ failure who had cardiopulmonary arrest survived. Survival after CPR for patients with a stable or improving APS was 32 percent (p < 0.01). CONCLUSIONS: Patients in the SICU who survived CPR had a stable or improving clinical course as determined by APS and GCS score, and had not had acute organ failure. Patients who were critically ill with a declining clinical course did not survive after CPR.

APACHE↗
PubMed1994

Initial clinical experiences with rescue unipolar radiofrequency thermal balloon angioplasty after abrupt or threatened vessel closure complicating elective conventional balloon coronary angioplasty.

OBJECTIVES: The purpose of this study was to evaluate the effectiveness of radiofrequency thermal balloon angioplasty and rescue procedure after abrupt or threatened vessel closure complicating elective percutaneous transluminal coronary angioplasty. BACKGROUND: Coronary angioplasty is an established therapy for ischemic heart disease. However, abrupt closure after successful angioplasty remains a serious problem. METHOD: We utilized a unipolar radiofrequency balloon in which a radiofrequency potential of 13.56 MHz was transmitted between the coil within the balloon and a plate electrode attached to the patient's body. The temperature within the balloon could be monitored through a thermistor within the balloon. From October 1991 through December 1993, 31 patients who had abrupt or threatened vessel closure during 1,005 consecutive elective coronary angioplasty procedures were randomly assigned to radiofrequency balloon angioplasty or to other procedures as rescue RESULTS: Fifteen patients were assigned to radiofrequency balloon angioplasty (5 with abrupt vessel closure and 10 with threatened closure). The average balloon temperature and inflation time were 62 +/- 9 degrees C and 129 +/- 62 s, respectively. Percent diameter stenosis decreased from 87 +/- 14% to 36 +/- 25% (p < 0.01). The procedure was successful in 14 patients. The rate of restenosis was 67%, but the success rate of repeat conventional coronary angioplasty for restenosed lesions was 86%. CONCLUSIONS: Radiofrequency balloon angioplasty is effective in the treatment of abrupt or threatened vessel closure complicating elective coronary angioplasty even though the procedure is associated with a relatively high rate of restenosis.

Aged↗
PubMed1994

Progesterone stimulates GnRH gene expression in the hypothalamus of ovariectomized, estrogen treated adult rats.

Gonadotropin-releasing hormone (GnRH) is a major neural signal for hypothalamic control of gonadotropin secretion which in turn influences gonadal steroid synthesis. Progesterone (P) is known to affect release and content of GnRH. The action mechanism of P on GnRH mRNA level remains, however, to be resolved. Here we report that P augments GnRH mRNA level in hypothalamic tissues derived from ovariectomized, estradiol-treated adult rats. The stimulatory action of P was time-dependent and lasted at least for 9 h. When RU486, a P receptor antagonist, was administered 1 hr before P treatment, it clearly blocked the stimulatory action of P on GnRH mRNA level. These results strongly suggest that P regulates GnRH gene expression in the rat hypothalamus, presumably through the P receptor-mediated mechanism.

Animals↗