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Biomedical subjects

M K Kim

Publications and source records attributed to M K Kim.

At least 163 records · Page 9Linked to original sources
PubMed1994

Identification of the pcaRKF gene cluster from Pseudomonas putida: involvement in chemotaxis, biodegradation, and transport of 4-hydroxybenzoate.

Pseudomonas putida PRS2000 is chemotactic to 4-hydroxybenzoate and other aromatic acids. This behavioral response is induced when cells are grown on 4-hydroxybenzoate or benzoate, compounds that are degraded via the beta-ketoadipate pathway. Isolation of a transposon mutant defective in 4-hydroxybenzoate chemotaxis allowed identification of a new gene cluster designated pcaRKF. DNA sequencing, mutational analysis, and complementation studies revealed that pcaR encodes a regulatory protein required for induction of at least four of the enzymes of the beta-ketoadipate pathway and that pcaF encodes beta-ketoadipyl-coenzyme A thiolase, the last enzyme in the pathway. The third gene, pcaK, encodes a transporter for 4-hydroxybenzoate, and this protein is also required for chemotaxis to aromatic acids. The predicted PcaK protein is 47 kDa in size, with a deduced amino acid sequence indicative of membership in the major facilitator superfamily of transport proteins. The protein, expressed in Escherichia coli, catalyzed 4-hydroxybenzoate transport. In addition, whole cells of P. putida pcaK mutants accumulated 4-hydroxybenzoate at reduced rates compared with that in wild-type cells. The pcaK mutation did not impair growth at the expense of 4-hydroxybenzoate under most conditions; however, mutant cells grew somewhat more slowly than the wild type on 4-hydroxybenzoate at a high pH. The finding that 4-hydroxybenzoate chemotaxis can be disrupted without an accompanying effect on metabolism indicates that this chemotactic response is receptor mediated. It remains to be determined, however, whether PcaK itself is a chemoreceptor for 4-hydroxybenzoate or whether it plays an indirect role in chemotaxis. These findings indicate that aromatic acid detection and transport are integral features of aromatic degradation pathways.

Acetyl-CoA C-Acyltransferase↗
PubMed1993

An AP-1-like factor and the pituitary-specific factor Pit-1 are both necessary to mediate hormonal induction of human thyrotropin beta gene expression.

The human thyrotropin beta (hTSH beta) gene is inducible by various agents including thyrotropin-releasing hormone, phorbol esters, or the adenylyl cyclase activator forskolin. In this study, we have characterized the functional properties of the TGGGTCA motif at -1/+6 of the hTSH beta gene that is similar to the consensus phorbol ester response element (TRE) or the consensus cyclic AMP response element (CRE). We suggest that both protein kinases C and A as well as TRH share a common mediator which recognizes the TGGGTCA element in activating the hTSH beta promoter. Following stimulation by phorbol esters, forskolin, or TRH, the TGGGTCA-specific factor acts together with the pituitary-specific transcription factor Pit-1 (or GHF-1) bound to upstream sequences at -128 to -61 to mediate the induction of the hTSH beta promoter. The induction requires that both factors bind to their own binding sites, but Pit-1 neither increases the binding of the TGGGTCA-specific factor to its target sequences nor associates with this factor to form a heterodimer. The TGGGTCA-specific factor is present in three cell lines tested and is composed of protein(s) immunologically related to c-Jun and c-Fos but not to the CRE-binding protein, CREB. By using the hTSH beta reporter plasmids in which the TGGGTCA element is converted to consensus TRE or CRE motifs, we found that, within the context of the hTSH beta promoter, the TGGGTCA element is a more potent TRE or CRE than the consensus TRE or CRE sequences. Based upon the results of this study, we propose a model in which the TGGGTCA-specific AP-1-like factor functionally cooperates with the tissue-specific factor Pit-1 to activate the hTSH beta gene.

Base Sequence↗
PubMed1993

Purification and characterization of NAD glycohydrolase from rabbit erythrocytes.

The NAD glycohydrolase (NADase) was solubilized from intact erythrocytes with bacterial phosphatidylinositol-specific phospholipase C and purified to homogeneity by affinity chromatography on Cibacron blue-agarose. This purification procedure resulted in an approximately 85-fold purification with an overall recovery of 75%. The purified NADase has a molecular weight of 65,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 63,000 as determined by gel permeation column chromatography at pH 7.0. Two hybridoma cell lines secreting antibodies against NADase were established and the antibodies recognized the purified enzyme as well as a 65-kDa band from the extracts of rabbit erythrocyte ghost. The enzyme displayed a Km of 43 microM for beta-NAD, a Vmax of 23 mumol/min/mg, a broad pH optimum around pH 7.0, and pI of 5.0. Nicotinamide and isoniazid are inhibitors (Ki values, 2.5 and 3.5 mM, respectively) of the noncompetitive type. Adenosine diphosphoribose acts as a competitive inhibitor (Ki = 2.0 mM). Cibacron blue 3GA is a potent competitive inhibitor of NADase (Ki = 96 nM). The purified enzyme splits beta-NAD, NADP, and nicotinamide hypoxanthine dinucleotide among the compounds tested and does not exhibit transglycosidase activity. Amino acid composition of the rabbit erythrocyte enzyme differed from that of NADases of other species, and the purified NADase contains 8% carbohydrate and a stoichiometric amount of inositol.

Adenosine Diphosphate Ribose↗
PubMed1993

The photic sneeze reflex as a risk factor to combat pilots.

The tendency to sneeze upon exposure to bright light is autosomal dominant and affects 18-35% of the population. This uncontrolled sneezing may represent a danger to pilots during flight. Testing was conducted using Ditric narrow band (+/- 10 nm) interference filters. Wavelengths at 430, 532, and 560 nm were tested with a GE 500-W photoflood BCA #1 bulb at constant intensity. Subsequent testing of military and civilian aviation goggles and sunglasses was conducted using a Digikrom 240 monochromator. Repeated testing with interference filters in a clinical setting showed no effect on sneezing in a susceptible subject. The photic sneeze reflex does not appear to be mediated by specific wavelengths of light, but rather by the change in light intensity. This could trigger an unexpected sneezing episode during critical periods of flight. This is an unrecognized and previously unreported danger to fixed-wing and rotary aircraft pilots.

Aerospace Medicine↗
PubMed1993

Possible novel action of ouabain: allosteric modulation of vascular serotonergic (5-HT2) and angiotensinergic (AT1) receptors.

Experiments were carried out to determine the effects of ouabain and dihydroouabain, both at 10 microM, on the vasoconstrictor responses of isolated rabbit blood vessel rings to both serotonin and angiotensin II. Ouabain plus dihydroouabain increased the sensitivity of central ear artery to serotonin and markedly reduced the antagonist potency of 0.1 microM prazosin against serotonin in this blood vessel; dihydroouabain alone had no effect. Ouabain, markedly reversed the reduction of maximal contractile response by both 2-brom-d-lysergic acid diethylamide against serotonin in aorta and 2-n-propyl-4-trifluoromethyl-1-[(2'-1H-tetrazol-5yl)biphenyl -4- yl)methyl]imidazole-5-carboxylic acid (EXP 3892) against angiotensin II in femoral artery; dihydroouabain had no effect. Whereas both 10 microM ouabain and dihydroouabain produced nearly maximal inhibition of Na+K+ATPase, dihydroouabain failed to modulate the vasoconstrictor responses to either serotonin or angiotensin II. Thus, it is concluded that the vasoconstrictor modulatory effects of ouabain are mediated by mechanisms unrelated to Na+K+ATPase inhibition. The present results are consistent with the hypothesis that both 5-hydroxytryptamine2 and angiotensinergic receptors can exist in high and low activity states. It is proposed that 5-hydroxytryptamine2 receptors exist in a low activity state in the ear artery, or are converted to the low activity state by 2-brom-d-lysergic acid diethylamide in the aorta. Hypothetically, 2-n-propyl-4-trifluoromethyl-1- [(2'-(1H-tetrazol-5yl)biphenyl-4-yl)methyl]imidazole-5-carbo xylic acid also converted the angiotensinergic receptor to the low activity state in femoral artery. In all three cases, ouabain enhanced vasoconstriction to serotonin and angiotensin II, respectively, possibly by allosterically modulating the respective receptors in these vessels to their high activity states.

Allosteric Regulation↗
PubMed1992

The proto-oncogenes c-fos and c-jun modulate thyroid hormone inhibition of human thyrotropin beta subunit gene expression in opposite directions.

The sequence from -1 to +6 bp in the hTSH beta gene contains overlapping putative thyroid hormone and AP-1 response elements. We demonstrate interaction between the AP-1 constituents c-fos and c-jun and thyroid hormone receptor in this region by transient transfection experiments using a -125 to +37 bp hTSH beta fragment. T3 inhibition was completely abolished by c-jun, but increased threefold by c-fos. A single transversion mutation at +2 bp restored T3 inhibition in the presence of c-jun and markedly reduced binding of purified c-jun by gel mobility shift assay. Thus, c-fos and c-jun influence T3 inhibition of hTSH beta expression in opposite directions acting through a response element shared with thyroid hormone receptor. Control of the relative cellular levels of these two proto-oncogenes may play a major role in modulating thyroid hormone inhibitory responses.

Base Sequence↗
PubMed1992

Anaerobic growth of Rhodopseudomonas palustris on 4-hydroxybenzoate is dependent on AadR, a member of the cyclic AMP receptor protein family of transcriptional regulators.

The purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris converts structurally diverse aromatic carboxylic acids, including lignin monomers, to benzoate and 4-hydroxybenzoate under anaerobic conditions. These compounds are then further degraded via aromatic ring-fission pathways. A gene termed aadR, for anaerobic aromatic degradation regulator, was identified by complementation of mutants unable to grow anaerobically on 4-hydroxybenzoate. The deduced amino acid sequence of the aadR product is similar to a family of transcriptional regulators which includes Escherichia coli Fnr and Crp, Pseudomonas aeruginosa Anr, and rhizobial FixK and FixK-like proteins. A mutant with a deletion in aadR failed to grow on 4-hydroxybenzoate under anaerobic conditions and grew very slowly on benzoate. It also did not express aromatic acid-coenzyme A ligase II, an enzyme that catalyzes the first step of 4-hydroxybenzoate degradation, and it was defective in 4-hydroxybenzoate-induced expression of benzoate-coenzyme A ligase. The aadR deletion mutant was unaffected in other aspects of anaerobic growth. It grew normally on nonaromatic carbon sources and also under nitrogen-fixing conditions. In addition, aerobic growth on 4-hydroxybenzoate was indistinguishable from that of the wild type. These results indicate that AadR functions as a transcriptional activator of anaerobic aromatic acid degradation.

Amino Acid Sequence↗
PubMed1992

Glucose-6-phosphate dehydrogenase deficiency--report of 4 cases.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common hereditary enzyme disorder and more than 200 million people have a deficiency in this enzyme. It is a globally important cause of neonatal jaundice and causes life-threatening hemolytic crisis in childhood. At later ages, certain drugs such as antimalarials, and fava beans cause hemolysis among G6PD deficiency patients. The frequency and severity is influenced by genetic and cultural factors. It is common in Mediterranean, African, and some East Asian populations but rare in Korea. Four cases of G6PD deficiency which were first noticed in Korea are investigated with their clinical features.

Child↗
PubMed1991

Alcoholic pellagra encephalopathy combined with Wernicke disease.

Clinical and postmortem findings of a case that had combined alcoholic pellagra encephalopathy and Wernicke disease are described. This 51-year-old malnourished and chronic alcoholic man presented with progressive mental deterioration, pellagra dermatitis, hypertonus of the neck and other musculatures, myoclonic jerks with bizarre involuntary movements, in addition to total external ophthalmoplegia and gait disturbance. After administration of multivitamins, including thiamine and nicotinamide, these neurologic abnormalities were dramatically improved in a few days. However, the patient died thereafter because of sepsis associated with pneumonia. Postmortem examination revealed marked abnormalities in CNS, characterized by diffuse atrophy of gray matter and widespread neuronal degeneration and characteristic central chromatolysis in pontine nuclei, dentate nuclei, cranial nerve nuclei in the brain stem, Betz cells of the cerebral cortex, and Clarke's column and anterior horn cells of the spinal cord. There were also atrophy and gliosis of the mammillary bodies, degeneration and vascular proliferation of periaqueductal gray matter, and massive gliosis around the third ventricle. These neuropathological changes were compatible with symptoms of both alcoholic pellagra encephalopathy and Wernicke's disease, but they were also strongly suspected on clinical grounds.

Alcoholism↗
PubMed1991

Leiomyosarcoma arising in the great saphenous vein--a case report.

Though leiomyosarcoma usually occurs in the gastrointestinal tract and uterus, it rarely occurs in the wall of large veins and arteries. We present a case of primary leiomyosarcoma arising in the great saphenous vein of the left inner thigh and spreading for some extent along the vein in a 54 year old female. Diagnosis was confirmed by desmin stain and electron microscopy. Postoperative course was fine. This is the first report of this in Korean literature.

Female↗
PubMed1991

Behçet's disease in Brazil--a review of 49 cases with emphasis on ophthalmic manifestations.

At the Uveitis Clinic of the Department of Ophthalmology of the Escola Paulista de Medicina, São Paulo, Brazil, Behçet's disease was diagnosed in 49 patients, representing 2.0% of the total uveitis cases attended during the 16-year period from February 1974 to June 1990. Of these, 71% were men. The age of onset of the disease was between 9 and 61 years, with a mean of 29.6 years. The ethnic distribution was the following: 76% Caucasian, 14% darkly pigmented, 8% Mongoloid and 2% Negroid. HLA-B5 was found in 45.5% of the 11 Caucasian patients typed. In 34.5% of the cases, the ocular attack was the initial manifestation, alone or associated with other symptoms. Oral aphthae were recorded in 98% of the patients, genital ulcers in 55.1%, and skin lesions in 51%. Joint involvement was present in 44.9%, neurologic symptoms were evidenced in 3 patients, and 2 patients had major vascular involvement. The mean interval between the first manifestation of the disease and the onset of ocular involvement was 3.1 years, with a range of 4 months to 14 years. The interval between affections of both eyes ranged from 0 to 2 years; in 38.4% of the cases it occurred within one month. Anterior and posterior segment involvement was seen in 85.7% of the patients. Hypopyon was observed in 34.7% of the cases. Seven patients did not present iridocyclitis at any time in the course of their disease. We did not see any cases with only anterior segment involvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Applications of staffing, scheduling, and budgeting methodologies to hospital ancillary units.

A computer-aided methodology for integrating the budgeting, staffing, and labor productivity systems of Ancillary Services using Respiratory Therapy as an example is presented. The data needed, staffing computations and schedules, and productivity analysis are presented and discussed. A summary of the predicted savings and other benefits for the application hospital are presented with comparisons to present productivity systems.

Budgets↗
PubMed1989

Ptosis surgery in the Asian eyelid.

There are many characteristic features of the Asian eyelid that differ significantly from those of the Occidental. The most noticeable of these are fullness of the upper eyelid and a low or absent upper lid crease. The patient may desire the preservation of these distinctive features during ptosis surgery. The surgical techniques of ptosis repair and the preservation of the typical Asian eyelid features during ptosis repair have not previously been described in the literature. This study describes the histologic differences between the Asian and Occidental upper eyelid, and the application of this anatomic knowledge to surgical techniques of ptosis repair with special emphasis on the preservation of the Asian eyelid features.

Adipose Tissue↗
PubMed1988

Intraocular trafficking of lymphocytes in locally induced experimental autoimmune uveoretinitis (EAU).

Experimental autoimmune uveoretinitis (EAU) was induced in naive Lewis rats by intravitreal adoptive transfer of 10(6) long-term S-antigen (S-Ag)-specific syngeneic T-lymphocyte lines of helper/inducer phenotype (ThS). These cells were stimulated with the T-cell mitogen concanavalin A (Con A) in culture for 48 hr and subsequently labeled with tritiated thymidine. Lymph node cells (LNC) cultured in parallel were used as controls. Histopathology and light microscopic autoradiography of the ocular tissue was performed at several time points to analyze the cell migration in relation to the development of EAU. The disappearance of both types of lymphocytes from the vitreous was similar and large numbers of host leukocytes were attracted into the vitreous. However, significantly more S-Ag-specific cells penetrated the retina and induced EAU (P less than 0.008). These results suggest that the development of EAU by intravitreal injection of S-Ag-specific T lymphocytes occurs by the migration of antigen-specific cells into the retina and recognition of the specific antigen, with subsequent release of soluble mediators that interact with the host effector cells, ultimately leading to specific photoreceptor damage.

Animals↗
PubMed1988

Identification of antigenic differences between the diabetogenic and non-diabetogenic variants of encephalomyocarditis virus using monoclonal antibodies.

The M variant of encephalomyocarditis (EMC) virus consists of two biologically distinct variants: one, diabetogenic D variant (EMC-D) and the other, non-diabetogenic B variant (EMC-B). These two variants cannot be distinguished by hyperimmune sera. Monoclonal antibodies were generated against EMC-D or EMC-B to identify antigenic differences between these two variants. Fourteen independent hybrid cell lines, selected from seven separate fusions of mouse myeloma cells to spleen cells isolated from mice immunized with EMC-D, consisted of 12 hybrids which produced monoclonal antibodies that neutralized both EMC-D and EMC-B, and two hybrids (ED-HJ-23 and ED-HJ-31) which produced monoclonal antibodies that neutralized EMC-D but not EMC-B. Similarly, 16 independent hybrid cell lines, selected from eight separate fusions using spleen cells prepared from mice immunized with EMC-B, consisted of 15 hybrids which produced monoclonal antibodies neutralizing both EMC-D and EMC-B, and one hybrid (EB-48A-F1) which produced antibody that neutralized EMC-B, but not EMC-D. The specificities of these monoclonal antibodies (ED-HJ-23, ED-HJ-31, EB-48A-F1) were further confirmed using an immunofluorescent technique. The D variant-specific monoclonal antibodies reacted with cells infected with EMC-D but not EMC-B. In contrast, the B variant-specific monoclonal antibody reacted with the cells infected with EMC-B but not EMC-D. It is concluded that the EMC-D- and EMC-B-specific monoclonal antibodies are able to identify antigenic differences between diabetogenic and non-diabetogenic variants of EMC virus which cannot be distinguished by hyperimmune sera.

Animals↗