Retransplantation of islets after simultaneous islet-kidney transplantation: a case report.
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Biomedical subjects
Publications and source records attributed to K W Kim.
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The heterogeneity and opacity of soil matrices pose considerable challenges for the quantification of soil contaminants. In order to investigate the feasibility of applying the Laser-Induced Fluorescence technique to measure contamination levels of soils, statistical analyses of contaminant levels and intensity of fluorescence were investigated in relation to soil properties. A significant correlation (R2 > 0.97) between contaminant levels and intensity of fluorescence was shown under different matrix conditions, such as moisture content and particle size distribution. Higher fluorescence intensities were obtained from soils with higher sand and moisture content. The statistical results in relation to the interaction between fluorescence intensity and matrix properties rejected the hypothesis that all properties of the matrices and contaminants had an equal influence on fluorescence. This implied that the concentrations of contaminants had the greatest contribution to the fluorescence intensity, but other variables also showed a considerable influence.
Nociceptin (N/OFQ) is a novel heptadecapeptide with an amino acid sequence similar to that of endogenous opioid peptide dynorphin A. Dynorphin have been reported to increase the secretion of atrial natriuretic peptide (ANP) via selective activation of kappa-opioid receptor in cultured atrial cardiocytes. The present study was designed to investigate the direct effect of N/OFQ on the ANP secretion in cultured neonatal rat cardiac myocytes via N/OFQ receptor (NOP) activation. The secretion of ANP from cultured neonatal cardiac myocytes was increased in terms of incubation time. N/OFQ, at a dose of 0.3, 1, 3, and 10 microM, caused increases in ANP secretion in a dose-dependent manner. The N/OFQ-induced ANP secretion was completely antagonized by antagonists of NOP, 1 microM each of [Phe1 (CH2-NH) Gly2] nociceptin (1-13)-NH2 ([FG]N/OFQ(1-13)NH2) or naloxone benzoylhydrazone. In contrast, naloxone (1 microM), the non-selective opioid receptor antagonist, did not alter ANP response to N/OFQ. N/OFQ at 3 microM inhibited basal and forskolin-stimulated cAMP production, which was partially antagonized with the pretreatment of [FG]N/OFQ(1-13)NH2. An increase in ANP secretion by N/OFQ was also partially blocked by the pretreatment of forskolin. Homologous competition studies in neonatal cardiomyocyte membranes revealed the presence of two distinct sites. The high affinity site (10.9 +/- 1.6 nM) was far less abundant than the low affinity site. Therefore, these results suggest that N/OFQ causes an increase in ANP secretion in cultured neonatal cardiac myocytes by decreasing cAMP through its binding sites.
OBJECTIVES: The aim of this study was to examine whether the APOE epsilon 4 allele also confers a risk for the cognitive impairment in normal aging. METHODS: We administered all the eight neuropsychological tests from the CERAD neuropsychological battery to the CVD-free, community-dwelling normal elderly individuals, and compared their performance by the occurrence of the APOE epsilon 4 allele. RESULTS: Either the impact of APOE epsilon 4 allele itself or its interaction terms with age and gender of the subjects did not influence the performance of the eight neuropsychological tests (epsilon p > 0.1 by ANCOVA). CONCLUSIONS: The APOE epsilon 4 allele is not a risk factor for the cognitive decline in normal elderly individuals regardless of age and gender.
OBJECTIVE: The purpose of this study was the development of the Korean Version of Alzheimer's Disease Assessment Scale (ADAS-K). METHOD: ADAS-K was administrated to 84 AD patients as well as 105 non-demented control subjects. Three aspects of reliability were tested. To evaluate the validity of ADAS-K, discriminant validity and concurrent validity were tested. To evaluate the sensitivity of ADAS-K to disease severity, all subjects, AD patients and control subjects, were grouped by CDR scale and their mean scores on ADAS-K were compared. RESULT: ADAS-K demonstrated high levels of reliability. Mean ADAS-K scores for AD patients were significantly different from the control group (p < 0.01). Furthermore, ADAS-K exhibited significant correlations with other tests and scales (range 0.45-0.85, p < 0.01). In ROC curve analysis, ADAS-K displayed high diagnostic efficacy and the optimal cut-off point was selected between 18/19. ADAS-K was able to discriminate the degree of AD severity according to CDR classification. Our results suggested that ADAS-K-cog was sensitive to very mild AD. CONCLUSION: We demonstrated that ADAS-K is a reliable and valid instrument not only for AD diagnosis but also for evaluation of its severity.
This study is designed to demonstrate the distribution of nociceptin, endogenous ORL1 receptor ligand, in the central nervous system of the Mongolian gerbil. To intensify the nociceptin-like immunoreactivity (NOC-LI), colchicine was administered into the lateral ventricle, at 48 h prior to the transcardiac perfusion. In the group without colchicine treatment, NOC-LI was observed in the fibres of the spinal dorsal horn, specifically in the superficial layers. However, the NOC-LI in the superficial layers disappeared after the administration of colchicine. In the brain, NOC-LI was prominent in the hypothalamus, hippocampus, cerebral peduncle, substantia nigra, dorsal raphe, periaqueductal grey, locus coeruleus and trapezoid nucleus. Colchicine treatment markedly intensified the NOC-LI in the somata of the central nervous system, whereas the untreated sections were too weak to observe and analyse. The distribution of NOC-LI provides informative data for studies of the neuronal circuit that nociceptin may be involved in.
Expression of the gene encoding metallothionein, a low molecular-weight cysteine-rich, stress-response and metal-binding protein was examined in human adipose tissue. The mRNA for MT-2A, a major metallothionein isoform in humans, was detected in subcutaneous fat using a specific antisense oligonucleotide probe. The level of MT-2A mRNA was significantly higher in a group of obese subjects than in a lean group, paralleling a similar increase in ob mRNA. A two-week period on a diet of 800 calories/day did not lead to any significant change in MT-2 mRNA levels. Separation of mature adipocytes from the cells of the stromal vascular fraction indicated that in human adipose tissue the metallothionein (MT-2A) gene is expressed both in adipocytes and in other cells of the tissue.
To examine the impact of the APOE epsilon4 allele on the cognitive functions of Alzheimer's disease (AD) patients, we administered the eight neuropsychological tests from the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery to 118 Korean AD patients. The impact of the APOE epsilon4 allele was significant in the Word List Recall Test (WLRT) and the Word List Recognition Test (WLRcT) only, and its impact was confined to the very mild AD (VMAD) patients (F = 7.65, d.f. = 2, p < 0.01 for WLRT; F = 3.27, d.f. = 2, p = 0.04 for WLRcT). In the VMAD group, the performance on the two tests of the APOE-epsilon4-positive patients was poorer than that of the APOE-epsilon4-negative patients. Our findings suggest that the impact of the APOE epsilon4 allele on cognitive functions in AD may be domain specific and confined to the early stage of AD.
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This research focused on the monitoring of the electrokinetic removal of heavy metals from tailing-soils, and emphasizes the dependency of removal efficiencies upon their physico-chemical states, as demonstrated by the different extraction methods adopted, which included aqua regia and sequential extraction. The tailing-soils examined contained high concentrations of target metal contaminants (Cd=179mgkg(-1), Cu=207mgkg(-1), Pb=5175mgkg(-1), and Zn=7600mgkg(-1)). The removal efficiencies of the different metals were significantly influenced by their speciations, mobilities and affinities (adsorption capacities) in the soil matrix. The removal efficiencies of mobile and weakly bound fractions, such as the exchangeable fraction were more than 90% by electrokinetic treatment, but strongly bound fractions, such as the organically bound species and residual fraction were not significantly removed (less than 30% removal efficiencies). In accordance with the general sequence of mobilities of heavy metals in soils, the removal efficiencies of more mobile heavy metals (Cd, Cu, and Zn) were higher than that of less mobile heavy metal (Pb).
GM3 synthase, which transfers CMP-NeuAc with an alpha2,3-linkage to a galactose residue of lactosylceramide, plays a key role in the biosynthesis of all complex gangliosides. In this study, cDNA and genomic clones encoding human GM3 synthase (hST3Gal V) were isolated, and the structural organization of the gene was determined. The hST3Gal V cDNA was identical in the coding region with cDNA that has been cloned previously from the HL-60 cells but different in the 5'-untranslated region (UTR). The hST3Gal V gene consisted of nine exons, which span approximately 44 kb, with exons ranging in size from 112 to 1242 bp. The coding region was located in exons 4-9, and all exon-intron boundaries except the acceptor site of intron 1 followed the GT-AG rule. The expression of this gene was highly restricted in both human fetal and adult tissues. By comparison of the nucleotide sequences of the genomic DNA with cDNA sequences including 5'-RACE products, we identified four isoforms (types 1-4) of the hST3Gal V mRNA that differ only in the 5'-UTR. Structural analysis of these isoforms suggests that mRNA isoforms of hST3Gal V are produced by a combination of alternative splicing and alternative promoter utilization.
We analyzed the transferrin (TF) and apolipoprotein E (APOE) genotypes of 164 probable Alzheimer's disease (AD) patients and 239 cognitively normal elderly controls in Koreans. We failed to detect a significant difference in genotypic frequencies and allelic frequencies of the TF polymorphism between the AD group and control group (P>0.1 by Chi square test). The frequency of the TF C2 variant did not differ by the diagnosis when the APOE epsilon4-positive subjects and APOE epsilon4-negative subjects were analyzed separately (P>0.1 by Chi square test). The TF C2 variant did not influence the age-at-onset of AD independently or synergistically with the occurrence of the APOE epsilon4 allele (P>0.1 by ANOVA). The TF C2 variant did not confer a risk for AD in Koreans.
A putative seven transmembrane protein gene, stm1(+), which is required for proper recognition of nitrogen starvation signals, was isolated as a multicopy suppressor of a ras1 synthetic lethal mutant in Schizosaccharomyces pombe. Under nitrogen-deficient conditions, transcription of the stm1 gene was induced; deletion of stm1 was associated with early entry into G(1) arrest. Under nutritionally sufficient conditions, overexpression of Stm1 inhibited vegetative cell growth, resulted in decreased intracellular cAMP levels, increased the expression of the meiosis-specific genes ste11, mei2, and mam2, and facilitated sexual development in homothallic cells. However inhibition of vegetative cell growth and reduction of cAMP levels were not observed in a deletion mutant of the heterotrimeric G protein Galpha2 gene, gpa2, that is responsible for regulating intracellular cAMP levels, a key factor in determining the sexual development in S. pombe. Stm1 protein was shown to interact with Gpa2 through its C-terminal transmembrane domains 5-7. Mutation at Lys(199) in the C-terminal domain (stm1(K199A)) abolished the Stm1 overexpression effect on lowering cAMP levels. Induction of ste11, a meiosis-specific gene transcription factor, by Stm1 overexpression was enhanced in gpa2-deleted cells but was absent in a deletion mutant of sty1, a key protein kinase that links mitotic control with environmental signals and induces stress-responsive genes. Moreover, deletion of both stm1 and ras1 caused delayed entry into G(1) arrest in S. pombe when the cells were grown in a nitrogen-deficient medium. Thus we consider that the stm1 gene can function through Gpa2-dependent and/or -independent pathways and may play a role in providing the prerequisite state for entering the pheromone-dependent differentiation cycle in which heterotrimeric Galpha1 protein, Gpa1, and Ras1 play major roles. Stm1 could function as a sentinel molecule sensing the nutritional state of the cells, stopping the proliferative cell cycle, and preparing the cell to enter meiosis under nutritionally deficient conditions.
[reaction: see text] Lipase-catalyzed transesterifications in ionic liquids proceeded with markedly enhanced enantioselectivity. It was observed that lipases were up to 25 times more enantioselective in ionic liquids than in conventional organic solvents.
The excessive growth of a tumor requires high rates of glucose uptake and glycolysis and continuous recruitment of new blood vessels. Here, we provide several lines of evidence showing that pyruvic acid, the end product of glycolysis, exhibits strong angiogenic activity. Pyruvic acid promoted angiogenesis in chorioallantoic membrane assay and in vivo mouse Matrigel plug assay. Pyruvic acid also positively affects angiogenic cascade, DNA synthesis, migration, and tube formation in bovine aortic endothelial cells. Furthermore, mRNA expression of fibroblast growth factor receptor-2 and vascular endothelial growth factor was enhanced by pyruvic acid. These results strongly suggest that pyruvic acid plays an important role in angiogenesis for tumor growth and metastasis.
Studies of the effect of capsaicin (CAP) on the smooth muscle contractions have shown both contraction and relaxation in various preparations. The direct effect of CAP on gastric smooth muscle itself has not yet been reported, though CAP was reported to relax the isolated guinea-pig stomach by releasing nitric oxide from the CAP-sensitive sensory neurons. Here we showed an evidence that CAP evokes a prolonged relaxation of gastric antral circular smooth muscle (CAP-induced relaxation) by blocking the voltage-operated Ca2+ channels (VOCC) from inside of the cell. CAP suppressed dose-dependently the spontaneous contractions of guinea-pig gastric circular muscle strip under the condition without neural influence (IC50 = 5.8 microM). The inhibitory effects of CAP both on the high K+ contracture induced by 50 mM K+ Tyrode solution and on the slow waves recorded using a conventional intracellular microelectrode technique were similar to those of Ca2+ channel antagonists, indicating that Ca2+ influx through the VOCC is decreased by CAP. Ca2+ channel current (I(Ba)) decreased in a concentration-dependent manner on superfusing the physiological salt solution containing various concentrations of CAP. The steady-state activation and inactivation curves of I(Ba) were not affected by the treatment with CAP. The experiment using a synthetic water-soluble analog of CAP, DA-5018 x HCl, suggested that the acting site of CAP is present in the intracellular side. Spontaneous transient outward K+ currents (STOCs) recorded at a holding potential of 0 mV were also inhibited by CAP and verapamil, Ca channel blocker. Taken together, these results indicate that CAP-induced relaxation is associated with the direct inhibitory action on the VOCC from inside of the cell.
The photochemical behavior of 2-halo-N-pyridinylbenzamide (1-4 in Chart 1) was studied. The photoreaction of 2-chloro-N-pyridinylbenzamides 1a, 2a, 3a, and 4 afforded photocyclized products, benzo[c]naphthyridinones (6-9 and 16), in high yield, whereas the bromo analogues 1b, 2b, and 3b produced extensively photoreduced products, N-pyridinylbenzamides (1c, 10, and 11), with minor photocyclized product. Since the photocyclization reaction of 2-chloro-N-pyridinylbenzamide is retarded by the presence of oxygen and sensitized by the presence of a triplet sensitizer, acetone or acetophenone, a triplet state of the chloro analogue is involved in the reaction. Since several radical intermediates, particularly n-complexes of chlorine radical, are identified in the laser flash photolysis of 2-chloro-N-pyridinylbenzamide, an intramolecular cyclization mechanism of phenyl radical assisted with n-complexation of chlorine radical for the cyclization reaction is proposed: the triplet state (78 kcal/mol) of the chloro analogue (1a), which is populated by the excitation of 1a undergoes a homolytic cleavage of the C-Cl bond to give phenyl and chlorine radicals; while chlorine radical holds the neighbor pyridinyl ring with its n-complexation, the intramolecular arylation of the phenyl radical with the pyridinyl ring proceeds to produce a conjugated 2,3-dihydropyridinyl radical and then the conjugated radical aromatizes to afford a cyclized product, benzo[c]naphthyridinone by ejecting a hydrogen. The photoreduction product can be formed by hydrogen atom abstraction of the phenyl sigma radical from the environment.
STUDY DESIGN: An examination of surgically obtained herniated lumbar disc tissues performed by using immunohistochemical staining and the DNA nick end labeling method. OBJECTIVE: To investigate the cell type that expresses Fas ligand (FasL) and any evidence of apoptosis of the disc cells in herniated lumbar disc tissues. SUMMARY OF BACKGROUND DATA: The Fas/FasL system is involved in delivering a death signal that rapidly commits the cells to apoptosis. In the authors' previous study, the expression of Fas on disc cells was identified in herniated lumbar disc tissue. METHODS: Twenty-three herniated lumbar disc tissues (contained disc, n = 9; noncontained disc, n = 14) were examined to investigate the cell type that expresses FasL and any evidence of apoptosis of the disc cells by using immunohistochemical staining and the DNA nick end labeling method, respectively. The percentage of FasL-positive disc cells was calculated and compared with clinical and radiologic data. RESULTS: FasL was expressed in the cytoplasm of the disc cells, and nuclear DNA fragmentation in a few disc cells was identified. A higher degree of FasL expression in disc cells was found in noncontained discs than in contained discs (P < 0.05). The percentage of FasL-positive disc cells significantly increased with the patient's age (P < 0.05), but not with the degree of disc degeneration (P > 0.05). CONCLUSION: The current results indicate that disc cells, after herniation, undergo apoptotic cell death via autocrine or paracrine FasL mechanisms by the disc cells themselves.