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Biomedical subjects

J H Woo

Publications and source records attributed to J H Woo.

33 records · Page 2Linked to original sources
PubMed1997

Regulation of toxic shock syndrome toxin-1 gene in Staphylococcus aureus.

Staphylococcus aureus produces various proteins in response to discrete signals from the external environment like many other pathogenic microorganisms. Certain staphylococcal exoproteins including toxic shock syndrome toxin-1 (TSST-1) are secreted according to the stimuli from the environment, and the quantity synthesized is influenced by a number of different parameters. Using a transposon Tn551-mediated mutagenesis, a mutant (RN 6390) defective in TSST-1 from synthesis was constructed. TSST-1 from wild strain and mutant stain were purified and quantitated from culture supernatants of Staphylococcus aureus. The mutant strain RN 6390 produced only 2% of TSST-1 compared with that produced by the wild strain RN4282. Southern blot hybridization with a tst (TSST-1 gene) probe indicated that the inactivated chromosomal locus is distinct from the tst. These results suggest that transposition by Tn551 inactivated a chromosomal locus whose activity was essential for the expression of the TSST-1 gene.

Bacterial Toxins↗
PubMed1997

Compensatory growth in dairy heifers: the effect of a compensatory growth pattern on growth rate and lactation performance.

The objective of this study was to improve the efficiency of growth and lactation performance of dairy heifers fed for a stair-step growth pattern. Twenty-four young Holstein heifers were randomly assigned to either control or test groups. The test group was fed according to a schedule of 3, 2, 4, 2, 5 and 2 mo in which feed intake was alternately 20% below or 25% above requirements. Heifers that were subjected to the stair-step growth pattern gained more body weight and consumed less dry matter, resulting in improved efficiency of growth compared with that of controls (7.8% vs. 8.3%). First estrus, first conception, gestation period, services per conception, and calving difficulty (dystocia) were not affected by stair-step growth. Concentration of growth hormone in blood serum was elevated during feed restriction for the test heifers; however, during refeeding, growth hormone was decreased compared with that in the blood serum of control heifers. Mammary tissues obtained by biopsy from heifers in middle and late pregnancy were used for chemical composition analysis. Stair-step growth increased DNA, RNA, protein, the ratio of RNA to DNA, and the ratio of protein to DNA. Lipid decreased in the mammary tissue of test heifers in late pregnancy (9.5 mo). Heifers in the test group yielded approximately 9% more milk than did heifers in the control group. These results indicate that compensatory growth can contribute to the improvement of growth efficiency and lactation performance.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Diagnosis and treatment of bacterial pneumonia in Korea.

Even with advancements in knowledge the problem of pneumonia will not be eliminated. It should be understood who is at risk, why such people develop pneumonia, what causes the pneumonia, and respiratory infection should be managed and prevented. The relative frequency of the isolation of various etiologic agents that cause bacterial pneumonia differ according to age group, geography, socio-economic status, underlying disease, time of year, and possible concomitant viral illnesses. Prompt identification of the causative agent is vital in the management of pneumonia. The present status of elucidating the etiologic agent is far from complete and recently, newer techniques using DNA probes and polymerase chain reactions were used for the identification of microbial pathogens. The timely use of appropriate systemic antibacterial therapy eradicates the pathogens. Considering the alterations of the etiologic agents of bacterial pneumonia and antibiotic susceptibilities, attention should be directed to the usage of antimicrobial agents in order to maximize the efficacy and the therapeutic implications.

Community-Acquired Infections↗
PubMed1996

A case of disseminated coccidioidomycosis--autopsy report.

Disseminated coccidioidomycosis is a systemic fungal infection that is occurring more commonly and causes high mortality in patients with compromised host defense or debilitated. It is endemic in certain areas of North, Central, and South America. Increasingly, cases are being recognized outside the endemic area, due to travelers who have visited an endemic area. We experienced a case of disseminated coccidioidomycosis, as a reactivation of infection acquired earlier in a patient, who was a former resident of an endemic area.

Amphotericin B↗
PubMed1996

Idiopathic granulomatous hepatitis manifested with fever of unknown origin.

Idiopathic granulomatous hepatitis is a rare disease of unknown cause that is characterized by recurrent fevers and granuloma in the liver. Attempts to define an exact etiology of the fever of granulomatous hepatitis frequently do not yield a precise diagnosis. Idiopathic granulomatous hepatitis was confirmed after a thorough work up and negative cultures and serologies were obtained, and in the absence of another condition that could lead to granulomas in the liver. We have experienced a 67-year-old female patient who presented with prolonged fever for 2 months and revealed granuloma in liver biopsy. She was treated with glucocorticosteroid and defervescence resulted.

Aged↗
PubMed1995

Bacteremia with nontyphi Salmonella and therapeutic implication.

OBJECTIVES: The recent decades witnessed the increased incidence of bacteremia with nontyphi Salmonella, especially in patients with underlying diseases. To evaluate clinically the patients with bacteremia by nontyphi Salmonella, we investigated the clinical records of the patients. METHODS: Retrospective study was performed on 30 cases of bacteremia with nontyphi Salmonella admitted to Soon Chun Hyang University Hospital from 1987 to 1993, and we analyzed with regard to age distribution, underlying diseases, clinical presentation and fatality. RESULTS: Children below 2 years of age were seven patients and patients over 55 years of age were 8 patients. The male to female ratio was 3:2. Only five cases were nosocomially acquired. More than two-thirds (21 patients) had no discernible other illness at the time of their bacteremia. A quarter of the patients presented without gastrointestinal manifestation. There were four deaths in the 30 patients with nontyphi Salmonella septicemia (13.3%). CONCLUSIONS: We investigated the clinical characteristics of 30 cases of non-typhi Salmonella bacteremia, which has a relatively high incidence nowadays while, to the contrary, Salmonella typhi trends toward being on the decrease in Korea.

Adolescent↗
PubMed1992

Nosocomial Legionnaire's disease--a case report and review of the literature.

We report a case of nosocomial legionellosis in a 63 year-old man who was managed with neurosurgery under the diagnosis of subarachnoidal hemorrhage and complicated pneumonia in the intensive care unit. A legionella species was reported from sputum culture and direct immunofluorescent antibody test revealed L. pneumophila (serogroup 2). Our patient's pneumonia was cured with medical therapy including erythromycin and was the first case of microbiologically confirmed legionellosis in Korea.

Cross Infection↗
PubMed1992

Subcutaneously implanted catheters reduce the incidence of peritonitis during CAPD by eliminating infection by periluminal route.

UNLABELLED: Recent experiences with Y-connectors suggest that the flush-before-fill effectively reduces intraluminal infection. Periluminal infection, however, remains an important route of peritonitis (P). We have recently reported reduced P incidence with the introduction of a new access technique as described by Moncrief in which the external segment of peritoneal catheter is left implanted subcutaneously for 6 weeks before exteriorization and bag exchanges. P developed once every 14.0 patient-mos with the new access while the incidence was one episode per 10.7 mos with conventional access. Significantly fewer patients with the new access compared to those with conventional access experienced P during the observation period (p < 0.01). Although the overall incidence of exit-site infection (ESI) was not different, there were significantly fewer episodes of simultaneous P and ESI with the new access (2P in 47 episodes of ESI) than with conventional access (36P in 126 ESI). While 10 of the 36 episodes of simultaneous infection in the conventional technique were caused by same organisms, none of the 2 episodes with the new access technique was caused by same organisms. CONCLUSION: The results of this study suggest that the new access technique reduces P incidence by virtually eliminating infection by the periluminal route.

Adolescent↗
PubMed1990

A case of laboratory-acquired murine typhus.

We encountered a 32-year-old Korean woman who developed murine typhus in a laboratory. She worked as a technician in a laboratory for rickettsial disease. Immunofluorescence test with rickettsial antigen (R. typhi) was positive at 1: 320 on admission and 1: 1280 after 4 weeks. A dose of 200 mg of doxycycline for 7 days proved to be effective for her condition.

Adult↗
PubMed1984

Cefoperazone in the treatment of postsurgical wound infection, sepsis, and abscess of the spinal cord and brain.

Cefoperazone was used in the treatment of 23 cases of serious bacterial infection in 20 patients. Ten postoperative scalp wound infections, five infections at the site of tracheostomy, four cases of extradural spinal cord abscess, three cases of sepsis, and one abscess of the cerebellopontine angle were treated with cefoperazone (1 to 2 gm BID, usually for seven to 27 days). There were excellent or good clinical responses in 87% (20/23) of the cases (14 of the 15 postsurgical wound infections, three of the four cases of spinal cord abscess, and all three cases of sepsis). Most of the organisms isolated from the patients' cultures were sensitive to cefoperazone. Excellent or good responses occurred in ten of the 12 infections due to Staphylococcus aureus, in all three infections due to Pseudomonas sp, all three due to Citrobacter freundii, the two due to Serratia marcescens, one of the two due to Klebsiella sp, and the one due to Escherichia coli. Two patients with ventriculitis were clinically improved by three 1-gm infusions, via a shunt, of cefoperazone. No adverse effects of the antibiotic therapy were reported.

Abscess↗
PubMed1980

Clonidine on the pressor response to raised intracranial pressure.

We attemptedto clarify the mechanism of the pressor response to raised intracranial pressure (ICP) in urethane-anesthetized rabbits. Intraventricular clonidine inhibited the pressor response to raised ICP, and intraventricular phentolamine antagonized the inhibitory effect of clonidine on the pressor response. In reserpine-treated rabbits the pressor response to raised ICP was not observed. Following intraventricular norepinephrine, however, the pressor response was observed. Intraventricular clonidine inhibited the pressor response that could be observed in the reserpine-treated rabbits following the intraventricular norepinephrine. These results suggest that the central sympathetic neurons play an important role in producing the pressor response to raised ICP.

Animals↗
PubMedDate not supplied

Time-kill studies of antimicrobial combinations including cefotaxime, ceftriaxone, vancomycin and meropenem against cephalosporin-resistant Streptococcus pneumoniae.

BACKGROUND: Resistance of Streptococcus pneumoniae to penicillin is now widespread and rapidly increasing all over the world. This has led to the critical need for alternative antimicrobial therapy. METHODS: To assess the activities of antimicrobial combinations, including cefotaxime, ceftriaxone, vancomycin and meropenem, time-kill studies were conducted against five strains of penicillin- and cephalosporin-resistant S. pneumoniae at clinically achievable antimicrobial concentrations in cerebrospinal fluid. RESULTS: Combinations of an extended-spectrum cephalosporin with vancomycin were not synergistic. Meropenem had a comparable bactericidal activity to those combinations, and its killing activity was not affected by the addition of cefotaxime, ceftriaxone or vancomycin. CONCLUSIONS: It is suggested that meropenem could be an effective alternative for the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis. However, more clinical data are required before it can be recommended as an effective antimicrobial agent for such cases.

Anti-Bacterial Agents↗
PubMedDate not supplied

Diffusion tensor imaging in amyotrophic lateral sclerosis: volumetric analysis of the corticospinal tract.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) allows direct visualization and volumetric analysis of the corticospinal tract (CST). The purpose of this study was to determine whether color maps and fiber tracking derived from DTI data are valuable in detecting and quantifying CST degeneration in patients with amyotrophic lateral sclerosis (ALS). METHODS: Sixteen patients with ALS with clinical signs of upper motor neuron (UMN) involvement and 17 healthy subjects were studied with the use of DTI. Disease severity was determined by means of the ALS Functional Rating Scale-Revised (ALSFRS-R) and an UMN involvement score. DTI was acquired with a 12-direction, single-shot, spin-echo echo-planar sequence. The CST from the lower pons to the corona radiata at the level of the corpus callosum on 4 contiguous coronal sections was manually segmented by using color maps generated from the DTI data. The left and right CST volumes were measured separately and normalized to the total intracranial volume. Normalized CST volumes were compared between patients with ALS and healthy subjects. RESULTS: The CST volumes of patients with ALS were significantly reduced (P < .01, unpaired t test) compared with healthy subjects, in both affected and nonaffected hemispheres. No significant correlation was found between CST volumes and any of the clinical parameters, including disease duration, ALSFRS-R, or UMN involvement score. CONCLUSION: This study shows that volumetric analysis by using DTI-based color maps is valuable in detecting and monitoring structural degeneration of the CST. This will lead to objective and quantitative assessment of axonal degeneration in ALS.

Adult↗