Biomedical subjects

K K Kim

Publications and source records attributed to K K Kim.

At least 73 records · Page 4Linked to original sources

PubMed1997

The need for inotropic support in a subgroup of infants with severe life-threatening respiratory syncytial viral infection.

BACKGROUND: We experienced an unusual complication of life-threatening respiratory syncytial viral disease cardiovascular compromise. Life-threatening respiratory syncytial virus (RSV) infection has predominancy involved with ventilatory support for respiratory distress and/or failure. We performed a retrospective chart review of 20 consecutive infants admitted to the pediatric intensive care unit (PICU) for impending respiratory failure. METHODS: Seventeen required ventilatory support. As part of the infants' initial assessment, blood pressure, distal perfusion [capillary refill time (CRT) > or = 3 sec], decreased peripheral pulses, and peripheral mottling were used to determine cardiovascular compromise. These infants received volume resuscitation either at the referring facility or the PICU until euvolemia was obtained, as determined by central venous pressure (CVP) monitoring (between 3 to 7 cm H20). Nine of the 20 infants did not respond to volume resuscitation alone and required vasopressor support in the form of: Dopamine (7 patients, 5-10 micrograms/kg/min), Dobutamine (2 patients, 5-7 micrograms/kg/min), and one who expired required both Epinephrine (600 ng/kg/min) and Dopamine (10 micrograms/kg/min). The mean ages of these 9 patients were 6.2 +/- 3.4 weeks (range 3-12 weeks), the mean duration of ventilation was 7.2 +/- 4.1 days (range 4-12 days). The mean duration of pharmacologic support was 69.7 +/- 47 hours (range 14-168 hours). The mean ages of RSV+ infants not requiring inotropic support was 19.4 +/- 27.4 weeks (range 1-90 weeks), and mean duration of ventilation was 5.5 +/- 5.9 days (range 2-20 days). RESULTS: The inotrope treated patients were weaned from pharmacologic support prior to extubation, without any hemodynamic deficits. Our experience with this rather high incidence of hemodynamic complications during this RSV epidemic was unexpected. CONCLUSION: These results substantiate the fact that younger patients with RSV disease are at both greater risk for pulmonary complications and cardiovascular deterioration and may thus benefit from pharmacologic support.

Cardiotonic Agents↗

PubMed1996

Mouse RAD50 has limited epitopic homology to p53 and is expressed in the adult myocardium.

Previous studies have identified a 180-kDa mouse cardiomyocyte phosphoprotein with limited epitopic homology to p53. In this study, the protein was purified and partially sequenced. Oligonucleotide probes based on the available amino acid sequence data were used to isolate cDNA clones. Sequence analyses revealed that the clones encoded a protein with regional homology to the yeast RAD50 gene product. Expression of the mouse cDNA rescued the methyl methanesulfonate-sensitive phenotype in rad50 mutant yeast, indicating that the cardiomyocyte phosphoprotein is the mammalian homologue of the yeast RAD50 gene product. Fluorescence in situ hybridization analyses localized the mouse RAD50 gene to the A5-B1 region of chromosome 11. Northern blot analyses demonstrated a complex pattern of RAD50 expression during mouse development which was further complicated by the presence of several alternatively spliced transcripts. High levels of RAD50 expression was evident in the adult myocardium, a somewhat surprising observation given the absence of DNA synthesis in adult cardiomyocytes.

3T3 Cells↗

PubMed1996

A critical role of Sp1- and Ets-related transcription factors in maintaining CTL-specific expression of the mouse perforin gene.

This study was designed to determine the potential cis-elements involved in transcriptional regulation of the mouse perforin gene. DNase I hypersensitive site (DHS) mapping revealed that the perforin locus contained six DHS within 7.0 kb of the 5' upstream sequence (-7.0 kb) and two DHS in intron 2. The six 5' upstream and one intronic DHS were detected in only perforin-expressing lymphocytes. Chloramphenicol acetyltransferase (CAT) activities directed by 5' upstream promoter were detected preferentially in perforin-expressing cell lines. A construct termed PFP5a containing -795 bp exhibited the highest CAT activity, and PFP9a20 containing only -73 bp also produced significantly high CAT activity in CTLL-R8 cells. The proximal region in PFP9a20 contained two potential Sp1 binding sites (GC box and GT box) and one Ets binding site (EBS). Electrophoretic mobility shift assay showed that each of the cis-elements bound specific protein factors. When single-point mutation was introduced to each GC box, EBS, and GT box in PFP9a20, at least 3-fold less CAT activity was observed in CTLL-R8 cells. To confirm the importance of the three cis-acting elements in the perforin gene expression, point mutation was introduced again to each proximal GC box, EBS, and GT box of PFP5a. The point mutations resulted in a 2.5- to 3-fold reduction of CAT activity. The results suggest that a combination of the three proximal cis-acting elements may constitute a minimal region responsible for CTL-specific expression of perforin.

Animals↗

PubMed1996

Hydroxylation of ent-kaurenoic acid to steviol in Stevia rebaudiana Bertoni--purification and partial characterization of the enzyme.

The diterpenoic compound steviol (ent-kaur-16-en-13-ol-19-oic acid) is the aglycone of sweet glycosides accumulated in Stevia rebaudiana Bertoni. This compound is the hydroxylated form of ent-kaurenoic acid (ent-kaur-16-en-19-oic acid; ent-KA). The hydroxylation of ent-KA to form steviol requiring NADPH and molecular oxygen was detected in stroma prepared from S. rebaudiana Bertoni. The enzyme was purified from leaf extract to apparent homogeneity with a molecular mass of 39 kDa. Taken together with the value of 160 kDa estimated for native enzyme, this suggested that the hydroxylating enzyme is a homotetramer. The N-terminal sequence was determined through 20 residues. The pH optimum was 7.5-7.8. Apparent Km values were 11.1 microM for ent-KA and 20.6 microM for NADPH. Its visible absorption spectrum suggested that the enzyme was flavoprotein. The stoichiometric relationship between the formation of steviol and the utilization of ent-KA and cofactors confirmed the equation ent-KA + NADPH + H(+) + O2-->steviol + NADPH(+) + H2O.

Amino Acid Sequence↗

PubMed1996

Polymerization of 5,6-dihydroxyindole-2-carboxylic acid to melanin by the pmel 17/silver locus protein.

Recent advances in melanogenesis have focused on the role of dihydroxyindole-2-carboxylic acid[(HO)2IndCOOH]. For example, it has been shown that formation of (HO)2IndCOOH from dopachrome is catalyzed by dopachrome tautomerase, that the melanogenic protein tyrosinase-related protein (TRP)-1 can oxidize (HO)2IndCOOH to its indole quinone, that (HO)2IndCOOH-melanins can be synthesized chemically, that mammalian melanins are naturally rich in (HO)2IndCOOH subunits, and that (HO)2IndCOOH is incorporated into melanins of melanomas in mice. The question thus emerges as to the mechanism(s) by which (HO)2IndCOOH and other precursors become incorporated into melanins in vivo. Accordingly, an activity was partially purified that catalyzed melanin formation with (HO)2IndCOOH as a substrate. Analyses of the (HO)2IndCOOH polymerization factor from Cloudman melanoma cells revealed the following: it was proteinaceous in that it was heat labile and destroyed by proteinase K; it was a glycoprotein in that it adhered to wheat germ agglutinin and was eluted with N-acetyl glucosamine; it was located predominantly in the melanosomal fraction of cell homogenates; the activity was reduced by exposure to the metal chelators EDTA and EGTA, but not by phenylthiourea, a tyrosinase inhibitor; the (HO)2IndCOOH polymerization reaction was inhibited by superoxide dismutase. In addition, the activity was found with the mouse pmel 17/silver locus protein immunopurified from human melanoma cells, and was significantly reduced in extracts of mouse melanocytes cultured from silver (si/si) mice compared to extracts from Si/Si melanocytes. In summary, an activity has been identified in human and mouse melanoma cells that catalyzes the superoxide-dependent polymerization of (HO)2IndCOOH to melanin in vitro, and appears to be a function of the pmel 17/silver protein of the human pmel 17 gene and the mouse silver locus.

Animals↗

PubMed1996

High scrotal incision for scrotal pouch orchiopexy.

Orchiopexy is one of the most common operations in children. It should be performed meticulously, and the testis should be anchored within the scrotum without undue tension. I present another method for making a pouch in scrotal pouch orchiopexy.

Cryptorchidism↗

PubMed1996

Three-dimensional structure of human cyclin H, a positive regulator of the CDK-activating kinase.

Cyclin-dependent kinases (CDKs), which play a key role in cell cycle control, are activated by the CDK activating kinase (CAK), which activates cyclin-bound CDKs by phosphorylation at a specific threonine residue. Vertebrate CAK contains two key components: a kinase subunit with homology to its substrate CDKs and a regulatory subunit with homology to cyclins. We have determined the X-ray crystal structure of the regulatory subunit of CAK, cyclin H, at 2.6 A resolution. Cyclin H contains two alpha-helical core domains with a fold similar to that of cyclin A, a regulatory subunit of CAK substrate CDK2, and of TFIIB, a transcription factor. Outside of the core domains, the N- and C-terminal regions of the three structures are completely different. The conformational differences between cyclin H and A structures may reflect functional differences between the two cyclins.

Amino Acid Sequence↗

PubMed1996

Developmental regulation of collagen differential expression in the rabbit bladder.

PURPOSE: It has been suggested that the amount and relative ratios of different types of collagen influence bladder compliance. To understand the mechanisms regulating collagen synthesis and degradation in the bladder we investigated the gene expression of collagen types I and III in the rabbit bladder during normal development. MATERIALS AND METHODS: New Zealand white rabbits ages fetus to adult were used for this study. The mid portion of the bladder wall was harvested. Northern blot hybridization was performed to analyze quantitatively collagen types I and III messenger (m) ribonucleic acid (RNA), and in situ hybridization was done to localize the messages. Corresponding protein distributions were obtained by immunohistochemical staining. RESULTS: Types I and III collagen are developmentally regulated at the level of gene expression. The temporal and spatial distribution of the mRNA transcripts of alpha 1(I) and alpha 1(III) correlates with extracellular protein deposition. Differential distribution of the mRNA transcripts is also developmentally regulated. CONCLUSIONS: This study characterizes the relationship between collagen gene expression and normal rabbit bladder development. The expression of alpha 1(I) and alpha 1(III) alters as the bladder grows. High levels and nonconcordant up and down regulation of different types of collagen mRNA during early development demonstrate the complexity of the extracellular matrix in a young bladder. This observation may be important in our understanding of the injury response in a developing versus mature bladder.

Animals↗

PubMed1996

Genomic organization and FISH mapping of human Pmel 17, the putative silver locus.

The Pmel 17 gene is expressed preferentially in pigment cells. It has been mapped to human chromosome 12 pter-q21 and mouse chromosome 10, near the silver locus. The Pmel 17 gene contains an insertional mutation at its carboxyl terminus in the silver mouse, suggesting that the silver locus might correspond to the gene. In the current studies, we have isolated and characterized human Pmel 17 genomic clones and employed FISH mapping for a precise localization of this gene in the human chromosome. The FISH mapping placed the Pmel 17 gene at human chromosome 12 q12-q13. The human gene consists of nine exons and eight introns, and the entire coding region of the gene spans approximately 7.9 kb of the human chromosome 12. The putative functional domains, such as the signal sequence, histidine-rich, 26-amino acid repeats, cysteinerich, transmembrane and cytoplasmic domains, were encoded by separate exons. Cistranscription elements such as a TATA, a CAT and other potential elements for pigment cell-specific gene expression were found within 1100 base pairs of the 5' flanking region.

Amino Acid Sequence↗

PubMed1996

Cardiomyocyte DNA synthesis and binucleation during murine development.

Cardiomyocyte DNA synthesis and binucleation indexes were determined during murine development. Cardiomyocyte DNA synthesis occurred in two temporally distinct phases. The first phase occurred during fetal life and was associated exclusively with cardiomyocyte proliferation. The second phase occurred during early neonatal life and was associated with binucleation. Collectively, these results suggest that cardiomyocyte reduplication ceases during late fetal life. Northern and Western blot analyses identified several candidate genes that were differentially expressed during the reduplicative and binucleation phases of cardiomyocyte growth.

Animals↗

PubMed1996

Chronic hypokalemia enhances expression of the H(+)-K(+)-ATPase alpha 2-subunit gene in renal medulla.

Recent molecular and physiological studies suggested that at least two H(+)-K(+)-adenosinetriphosphatase (H(+)-K(+)-ATPase) isozymes are expressed in the rat kidney and that these ion pumps respond to changes in dietary potassium balance. We used Northern analysis and in situ hybridization to analyze the expression of mRNA encoding the "colonic" isoform of the H(+)-K(+)-ATPase alpha-subunit (HK alpha 2) in normal and potassium-deprived (2 wk) rats. Control rats exhibited low levels of HK alpha 2 mRNA in the cortical and medullary thick ascending limb, distal convoluted tubule, connecting segment, and the entire collecting duct. The potassium-deprived rats expressed approximately fivefold higher levels of HK alpha 2 mRNA in the outer and inner medulla compared with controls, as well as hypertrophy and increased in situ hybridization signal in the intercalated cells of the inner stripe of the outer medullary collecting duct and the proximal inner medullary collecting duct. In contrast, renal cortical expression of HK alpha 2 mRNA was low and comparable in the two groups. Our results suggest that enhanced expression of the HK alpha 2 subunit gene in the renal medulla contributes to potassium conservation during chronic hypokalemia.

Animals↗

PubMed1996

Acute brachial neuropathy--electrophysiological study and clinical profile.

Acute brachial neuropathy (ABN) is a rare disease, characterized by an acute or subacute onset of pain followed by weakness of shoulder or arm muscles without trauma or traction injury. So the diagnosis of this clinical entity is not easy. The purpose of this study was to analyze retrospectively the ABN in 14 cases focusing on the clinical profile and to evaluate the effectiveness of electrophysiologic study in diagnosis of ABN with a new result helpful in localizing a brachial plexus disorder. The most helpful electrophysiologic data of ABN in my patients seemed to be abnormalities of low amplitude, abnormal right to left difference of compound motor action potentials (CMAPs) and sensory nerve action potentials (SNAPs) in axillary nerve, ulnar or median nerves. Results of nerve conduction velocity, terminal and F-wave latency were not as useful. But the electromyogram was most helpful in localization of upper or lower plexus lesions and cervical radiculopathy. The most striking clinical feature of ABN was the rapid onset of pain followed by the development of muscle weakness of shoulder girdle after a variable period or within four days. In contrast to other reports, intrinsic hand muscle weakness was observed in 3 cases with sensory changes in ulnar nerve distribution. The cervical radiculopathies (C5-C7 roots) were simultaneously combined with ipsilateral axillary neuropathy in 3 cases. In this study, decreased amplitude, abnormal right to left difference of SNAPs and CMAPs, and neurogenic EMG findings with normal data of NCV, terminal and F-wave latencies suggest that the pathology of ABN might not be a demyelinating process, but axonopathy.

Adult↗

PubMed1996

Preputial condition and urinary tract infections.

Recently, an increase in incidences of urinary tract infections in uncircumcised male infants has been reported. However, determining what is the best management for the prepuce of newborns and infants is still to be solved. I investigated prospectively how much foreskins are retracted with age and what correlations it has with urinary tract infection in 122 males children below 15 years of age. Under 6 months of age, the majority of the foreskins were unretractable. As they got older, over 3 years of age, their prepuces became retractable. The incidence of bacteriuria was 11.4% in uncircumcised but none in circumcised and hypospadias. In 8 patients showing bacteriuria, their foreskins were retracted below 25% in length. Among them, 5 patients, in whom E. coli were grown in their urine, showed radiologic renal abnormalities and suffered from high fever indicating systemic infection. However, the other 3 cases infected by Proteus mirabilis in their urine complained of only local penile symptoms.

Adolescent↗

PubMed1996

Exogenous causes of myoglobinuria--review of 26 cases.

In this article, I review various causes of exogenous myoglobinuria(MU) and its pathogenesis in 26 consecutive patients admitted to emergency room, Asan Medical Center and determine whether there is a relationship between concentration of urine myoglobin(Mb) and acute renal failure(ARF) as a complication of MU. Serum and urine Mb were measured by RIA using myoglobin kit(Daiichi, Inc., Tokyo, Japan). The most common disorder of MU was septic shock with hypotension, followed by crush syndrome, major arterial occlusion by thormbosis, alcohol intoxication with status epilepticus, intoxication of unidentified snake venom and drug ingestion. On the basis of this limited amount of data, there is a significant association between high concentration in urine Mb(> 300 ng/ml) and ARF(Fisher's exact test, p < 0.005). To minimize the chances of development of ARF, routine urine Mb levels should be checked on patients at risk, especially septic shock with hypotension.

Acute Kidney Injury↗

PubMed1995

Steviol and steviol-glycoside: glucosyltransferase activities in Stevia rebaudiana Bertoni--purification and partial characterization.

The leaves of Stevia rebaudiana Bertoni contain sweet compounds which are glycosides of diterpene derivative steviol (ent-13-hydroxykaur-16-en-19-oic acid). Its main constituents are stevioside (triglucosylated steviol; 13-O-beta-sophorosyl-19-O-beta-glucosyl-steviol) and rebaudioside-A (tetraglucosylated steviol; 2'-O-beta-glucosyl-13-O-beta-sophorosyl-19-O-beta-glucosyl-stev iol). From the extracts of S. rebaudiana Bertoni, two glucosyltransferases (GTases I and IIB) acting on steviol and steviol-glycosides were isolated, and another distinct activity (GTase IIA) acting on steviol was detected. Purified GTase I (subunit M(r) 24,600) catalyzed glucose transfer from UDP-glucose to steviol and steviolmonoside (steviol-13-O-glucopyranoside), but not to other steviol-glycosides. Apparent Km values were 71.4 microM for steviol and 360 microM for UDP-glucose. GTase IIB (subunit M(r) 30,700) showed a broad substrate specificity, acting on steviol, steviolmonoside, steviolbioside (13-O-beta-sophorosyl-steviol), and stevioside. Apparent Km values were 182 microM for steviol, 44 microM for steviolbioside, 95 microM for stevioside, and 385 microM for UDP-glucose. The two enzymes had a similar optimum pH at 6.5. They also acted effectively on ubiquitous flavonol aglycones, quercetin, and kaempferol and utilized kaempferol at a higher rate than steviol and steviol-glycosides. The apparent Km values of GTase I and IIB for kaempferol were 12 and 31 microM, respectively.

Chromatography, Gel↗

PubMed1995

Developmental expression of p107 mRNA and evidence for alternative splicing of the p107 (RBL1) gene product.

Expression of p107, a protein with homology to the retinoblastoma tumor suppressor (pRB), was monitored during murine development. Northern blot tissue surveys identified two transcripts of 4.9 and 2.4 kb that hybridized to a p107 cDNA clone. Expression of both transcripts was detected in fetal tissues, with particularly high levels in the liver and heart. In contrast, p107 transcripts were markedly decreased in most adult tissues examined. Molecular cloning analyses revealed that the 4.9- and 2.4-kb transcripts encoded proteins with deduced molecular masses of 119 and 68 kDa, respectively. Genetic mapping studies suggested that the two p107 transcripts arose by alternative splicing of a common precursor. The protein encoded by the 2.4-kb transcript lacks the spacer and B motif of the "pocket domain," a region of homology between p107 and pRB that is required for binding to cell cycle regulatory proteins. Structural modifications resulting from alternative splicing may thus confer functional diversity upon the 119- and 68-kDa proteins.

Alternative Splicing↗

PubMed1995

Potential approaches for myocardial regeneration.

Cardiomyocytes in the adult mammal retain little or none of their developmental capacity for hyperplastic growth. As a consequence of this differentiated, nonproliferative phenotype, cardiomyocyte loss due to injury or disease is irreversible. Therapeutic intervention in end-stage diseased hearts is currently limited to cardiac transplantation. An increase in cardiomyocyte number in diseased hearts could improve function. Augmentation of the cardiomyocyte population may be achievable by the expression of regulatory proteins in the myocardium, or by intracardiac grafting of exogenous cardiomyocytes.

Animals↗

PubMed1995

High-resolution crystal structure of the non-specific lipid-transfer protein from maize seedlings.

BACKGROUND: The movement of lipids between membranes is aided by lipid-transfer proteins (LTPs). Some LTPs exhibit broad specificity, transferring many classes of lipids, and are termed non-specific LTPs (ns-LTPs). Despite their apparently similar mode of action, no sequence homology exists between mammalian and plant ns-LTPs and no three-dimensional structure has been reported for any plant ns-LTP. RESULTS: We have determined the crystal structure of ns-LTP from maize seedlings by multiple isomorphous replacement and refined the structure to 1.9 A resolution. The protein comprises a single compact domain with four alpha-helices and a long C-terminal region. The eight conserved cysteines form four disulfide bridges (assigned as Cys4-Cys52, Cys14-Cys29, Cys30-Cys75, and Cys50-Cys89) resolving the ambiguity that remained from the chemical determination of pairings in the homologous protein from castor bean. Two of the bonds, Cys4-Cys52 and Cys50-Cys89, differ from what would have been predicted from sequence alignment with soybean hydrophobic protein. The complex between maize ns-LTP and hexadecanoate (palmitate) has also been crystallized and its structure refined to 1.8 A resolution. CONCLUSIONS: The fold of maize ns-LTP places it in a new category of all-alpha-type structure, first described for soybean hydrophobic protein. In the absence of a bound ligand, the protein has a tunnel-like hydrophobic cavity, which is large enough to accommodate a long fatty acyl chain. In the structure of the complex with palmitate, most of the acyl chain is buried inside this hydrophobic cavity.

Amino Acid Sequence↗