Search PubMed⌕ Search

Biomedical subjects

S H Oh

Publications and source records attributed to S H Oh.

At least 91 records · Page 5Linked to original sources
PubMed1996

Genetic and transcriptional organization of the Bacillus subtilis spc-alpha region.

We used chromosomal walking methods to isolate a 10.8-kb region from the major ribosomal protein (r-protein) gene cluster of Bacillus subtilis (Bs). The gene order in this region, given by gene product, was r-proteins L16-L29-S17-L14-L24-L5-S14-S8-L6-L18-S5-L30-L15-SecY-adenylate kinase (Adk)-methionine aminopeptidase (Map)-initiation factor 1 (IF1)-L36-S13-S11-alpha subunit of RNA polymerase-L17. The region cloned, therefore, contains the homologues for the last three genes of the Escherichia coli (Ec) S10 operon, together with entire spc and alpha operons. This Bs organization differs from the corresponding region in Ec by the inclusion of the genes encoding Adk, Map and IF1 between the genes encoding SecY and L36. Plasmid integration experiments indicated that all 22 genes comprise a single large transcriptional unit controlled from a major promoter which lies upstream from the gene encoding r-protein L16. Promoter probe experiments located lesser activities internal to this large transcriptional unit, the secY and map promoters. The secY promoter region (psecY) contained two activities, each principally functioning in the stationary growth phase when high protein export is required. Thus, the Bs S10-spc-alpha region differs from its Ec counterpart in both genetic and transcriptional organization. Given this difference in transcriptional organization, the mechanisms coordinating expression of the translational apparatus are also likely to differ between Ec and Bs.

Amino Acid Sequence↗
PubMed1996

Nucleotide sequence variation in the hypervariable region of the hepatitis C virus in the sera of chronic hepatitis C patients undergoing controlled interferon-alpha therapy.

Ten patients with hepatitis C virus (HCV) infection (experimental group) were treated with interferon-alpha (IF-alpha). Dosage was six million units per day for one week and then three times a week for another six months. Seven HCV-infected patients (control group) did not receive IF-alpha therapy. The hypervariable region (HVR) of HCV in the sera of patients was amplified by reverse transcription-polymerase chain reaction (RT-PCR), and the variation of amino acid sequence in this region was determined. Serum alanine aminotransferase (ALT) activities in five patients treated for six months with IF-alpha fell to the normal range, when HCV was not detected in the sera of three patients. The nucleotide sequence variation in HVR of HCV in the sera of five patients who responded well to the IF-alpha therapy was relatively less than that in another five patients who did not respond to IF-alpha therapy and those in the control patients. These results indicate that the effectiveness of IF-alpha therapy was related to the sequence variation of HVR of HCV. This may have resulted from the selection pressure by humoral antibodies directed to HVR of HCV. It is concluded that the higher rate of sequence variation in HVR of HCV was compatible with a lower degree of effectiveness of IF-alpha therapy.

Adult↗
PubMed1996

Quantitative three-dimensional anatomy of the subaxial cervical spine: implication for anterior spinal surgery.

Knowledge of the quantitative anatomy of the subaxial cervical vertebrae is essential to safely perform anterior cervical surgery and to ensure adequate decompression of neural structures. In spite of this, little has been published in the neurosurgical literature regarding the spatial relationship of the lower cervical vertebrae and the implications of this anatomy for anterior cervical surgery. We report the three-dimensional analysis of the mid- and lower cervical spine in 10 cadaver specimens for 50 disarticulated vertebrae and discuss the relevance of this analysis to surgery in this region. Measurements were made using real-time video analysis of images transferred from a Zeiss microscope equipped with an image splitter and a Sony charge-coupled device camera. Images were then transferred to an IBM personal computer-based image analysis system. Analysis of variance was used to test for significant differences among the C3-C7 vertebral measurements. Important relationships of the vertebral artery to the anteroposterior diameter of the vertebral bodies and its variations from C3 to C7 are discussed. The vertebral artery migrates posteriorly to anteriorly from C3 to C6 and posteriorly again at C7; the implications of these variations are discussed for decompression of the neural foramen. Another finding showing that the inter-Luschka distance increases from C3 to C7 is important for adequate lateral decompression in anterior cervical spinal surgery. The pedicle to the Luschka joint was measured at the different levels; the pedicle is lateral to the Luschka joint from C3 to C6 and medial to the joint at C7. This variation explains the lack of root decompression at some cervical levels, even when decompression extends to the Luschka joint bilaterally. We also report the measurements of the vertebral bodies and the spinal canal and compare the results with other published data. We think these measurements provide guidelines for operating on the anterior cervical spine, facilitate adequate decompression of the spinal cord and neural foramen, and increase the margin of safety of the surgeon.

Anthropometry↗
PubMed1996

Efficacy of hydrocolloid occlusive dressing technique in decubitus ulcer treatment: a comparative study.

The efficacy of hydrocolloid occlusive dressing technique was compared with that of the conventional wet-to-dry gauze dressing technique in decubitus ulcer of stage I and II. Forty-four patients were randomly divided into two treatment groups and each received treatment according to the two different protocols. As a result, 80.8% of the hydrocolloid occlusive dressing group (group 1) and 77.8% of the conventional wet-to-dry gauze dressing group (group 2) healed completely with no statistically significant difference between the two groups. However, the time required for complete healing was shorter in group 1 with 18.9 days compared to 24.3 days in group 2. Ulcer healing speed was also slightly faster in group 1 with 9.1 mm2/day compared to 7.9 mm2/day for group 2. Average treatment time spent by a medical staff member was significantly shorter in group 1 with 20.4 minutes/day compared to 2017 minutes/day in group 2. The hospital cost of the ulcer treatment was higher in group 2 compared to group 1 even without taking into consideration the medical personnel's labor cost. These results indicate that the hydrocolloid occlusive dressing technique offers less time consuming and less expensive method of treatment compared to the conventional technique in stage I and II decubitus ulcers.

Adult↗
PubMed1995

Chemical synthesis of 15-ketosterols and their inhibitions of cholesteryl ester transfer protein.

Described herein are the chemical syntheses of 3 beta-hydroxy-5 alpha-cholest-8(14)-en-15-one and 3 beta-hydroxy-5 alpha-cholest-8(14),16-dien-15-one from diosgenin and the examinations of their ability to inhibit the cholesteryl ester transfer protein (CETP). Clemmensen reduction of diosgenin gave cholest-5-ene-3 beta, 16 beta,26-triol. Tosylation of the latter compound gave cholest-5-ene-3 beta,16 beta,26-triol 26-tosylate which, upon reduction with LiAIH4, gave cholest-5-ene-3 beta,16 beta-diol. Hydrogenation-benzoylation of the latter to 5 alpha-cholest-3 beta,16 beta-diol 3 beta-benzoate followed by mesylation-elimination gave 5 alpha-cholest-16-ene-3 beta-ol 3 beta-benzoate. Controlled oxidation of the latter with CrO3-dimethylpyrazole gave 3 beta-hydroxy-5 alpha, 14 alpha-cholest-16-en-15-one 3 beta-benzoate. Oxidation of delta 16-15-one with SeO2 gave 3 beta-hydroxy-5 alpha-cholest-8(14),16-dien-15-one 3 beta-benzoate along with 3 beta-hydroxy-5 alpha, 14 beta-cholest-16-en-15-one 3 beta-benzoate. Selective hydrogenation of the delta 8(14),16-15-ketosteryl ester, followed by base hydrolysis gave 3 beta-hydroxy-5 alpha-cholest-8(14)-en-15-one. Hydrolysis of 3 beta-hydroxy-5 alpha-cholest-8(14),16-dien-15-one 3 beta-benzoate in basic media gave 3 beta-hydroxy-5 alpha-cholest-8(14),16-dien-15-one. The effects of the 15-ketosterols on the CETP activity were studied in vitro by incubating cholesteryl ester donor (HDL), cholesteryl ester acceptor (LDL) and human plasma as a CETP source at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticholesteremic Agents↗
PubMed1995

Evaluation of chemopreventive effect of dietary selenium-rich egg on mouse skin tumor induced by 2'-(4-nitrophenoxy)oxirane and 12-O-tetradecanoylphorbol-13-acetate.

Chemoprotective effect of dietary selenium (as sodium selenite or as Se-rich egg) on mouse skin tumor induced by topical application of 2'-(4-nitrophenoxy)oxirane (NPO) as tumor initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as tumor promoter was evaluated in relation to the dietary source and levels of selenium. Selenium supplementation (0.3 p.p.m.) to the basal diet (0.07 p.p.m. Se) as sodium selenite or as Se-rich egg brought about a 40 or 37% reduction respectively, in the incidence of papilloma formation at 12 weeks after NPO treatment. Tumor yield (number of papillomas per mouse) at 14 weeks after NPO treatment in the basal diet group, basal diet supplemented with 0.3 p.p.m. Se as sodium selenite group and basal diet supplemented with 0.3 p.p.m. Se as Se-rich egg group were 7.5 +/- 2.1, 2.7 +/- 2.3 and 4.1 +/- 3.5 respectively. Dietary supplementation of 1.0 p.p.m. See as Se-rich egg to the basal diet reduced the incidence and the multiplicity of papillomas during the early phase of promotion (11 weeks) but its antitumor activity decreased thereafter, indicating that the accumulation of tissue selenium above the saturated level may not be beneficial. Selenium concentrations in blood, liver and skin tissue of mice in basal diet group (0.33 +/- 0.02, 0.54 +/- 0.10 and 0.21 +/- 0.03 p.p.m. respectively) increased significantly ( P < 0.05) by the supplementation of 0.3 p.p.m. Se as selenite (0.58 +/- 0.02, 1.17 +/- 0.10 and 0.31 +/- 0.05 p.p.m. respectively), 0.3 p.p.m. Se as Se-rich egg (0.59 +/- 0.02, 1.25 +/- 0.11 and 0.33 +/- 0.06 p.p.m. respectively) and 1.0 p.p.m. Se as Se-rich egg (1.20 +/- 0.05, 2.32 +/- 0.28 and 0.51 +/- 0.01 p.p.m. respectively). Glutathione peroxidase activity in blood of mice of the basal diet group (2.4 +/- 0.4 EU/mg) increased significantly (P < 0.05) by dietary selenium supplementation (3.8 +/- 0.6 EU/mg in 0.3 p.p.m. Selenite; 3.7 +/- 0.8 EU/mg in 0.3 p.p.m. Se as Se-rich egg; 4.9 +/- 0.9 EU/mg in 1/0 p.p.m. Se as Se-rich egg) and the enzyme activities in liver and skin tissue also increased by 0.3 p.p.m. Se (as selenite or Se-rich egg) supplementation, but no further increases in their activities were obtained by 1.0 p.p.m. Se (as Se-rich egg). It is, therefore, concluded that a moderate level of dietary selenium (0.3 p.p.m.) has an efficient chemopreventive activity at the promotional stage of carcinogenesis and that dietary selenium rich egg as well as dietary selenite exerted antitumor activity.

Animals↗
PubMed1995

Effects of gamma-irradiation on intracellular proliferation of Toxoplasma gondii RH tachyzoites.

A quantitative assay was performed on the effects of gamma-irradiation (30-300 Gy) on intracellular proliferation of Toxoplasma gondii RH tachyzoites in human leukemic HL-60 cells and murine peritoneal macrophages by means of 3H-uracil uptake assay. Infected non-irradiation group (NI) and uninfected group (incubating only host cells) were prepared. The 3H-uracil uptake by tachyzoites of NI group 12-24 hrs after infection was 2,190-4,787 counts per minute for macrophages and 2,967-8,254 for HL-60 cells, whereas the irradiated tachyzoites revealed only 381-703 (100 Gy) and 218-408 (300 Gy) for macrophages, and 1,911-2,618 (30 Gy), 1,253-1,384 (70 Gy), 1,013-1,090 (100 Gy), and 483-588 (300 Gy) for HL-60 cells. The proliferation inhibition rate was similar in macrophages and HL-60 cells, for example, 89-94% and 80-94% respectively by 300 Gy, 12-24 hrs after infection. It is concluded that RH tachyzoites of T. gondii are severely affected by gamma-irradiation in their capability of intracellular proliferation.

Animals↗
PubMed1995

[Genetic status of Acanthamoeba spp. Korean isolates on the basis of RAPD markers].

Genetic status of Acanthamoeba spp. were tested on the basis of random amplified polymorphic DNA (RAPD) marker analysis. Four previously established Acanthamoeba species, 4 Korean isolates of Acanthamoeba sp., and one American isolate of Acanthamoeba sp. were analyzed by RAPD-PCR using an arbitrary decamer primers. Amplification products were fractionated by agarose gel electrophoresis and stained by ethidium bromide. Eighteen primers produced DNA amplification profiles revealing clear differences among 4 species. Nine of them also produced DNA amplification profiles which included some isolate-specific amplification products. On the basis of amplified fragments by 18 primers, the pairwise similarity indices between A. culbertsoni and other species (i.e., A. hatchetti, A. triangularis, A. polyphaga) were 0.300, 0.308, and 0.313, respectively. Similarity index between A. hatchetti and A. triangularis was 0.833. The mean similarity index among the 3 Korean isolates (YM-2, -3, -4) was 0.959 and 0.832 among them and 2 other species (A. hatchetti and A. triangularis). The mean similarity index among YM-5 and other Korean isolates (YM-2, -3, -4) was 0.237. However, the similarity index between YM-5 and A. culbertsoni was 0.857, which suggests that YM-5 is genetically more similar to A. culbertsoni than other Korean isolates. Phenogram reconstructed by UPGMA method revealed that there are two groups: one group consists of A. hatchetti, A. triangularis, and 3 Korean isolates (YM-2, -3, -4), and the other group consists of A. culbertsoni, A. polyphaga, HOV, and YM-5.

Acanthamoeba↗
PubMed1995

Inhibition of HBV replication by antisense oligodeoxyribonucleotides in HepG2 cells transfected with a cloned HBV DNA.

The effect of antisense oligodeoxyribonucleotides(oligo[dN]s) on hepatitis B virus(HBV) replication in HepG2 cells harboring a cloned HBV genome was examined. Antisense oligo(dN)s directed at translational initiation sites of S, pre C and P genes of HBV were treated to the cells and the amount of HBsAg and HBV DNA content were measured 72 hours after the treatment. HBsAg expressions in HepG2 cells harboring the HBV genome were inhibited 68%, 53%, and 46% by the treatment with antisense oligo[dN] directed at S, pre C, and P gene loci, respectively, and HBV DNA content in the cells was also reduced by the treatment of each antisense oligo[dN]. The doubling times of the cultured cells treated with 25 micrograms, 50 micrograms, and 100 micrograms of antisense oligo[dN]/ml medium were 43.3, 62.1, and 93.0 hours, respectively, compared with 37.5 hours of the untreated control cells. Cellular DNA synthesis was inhibited by the treatment with 100 micrograms/ml of antisense oligo [dN], however, no significant effect was observed by the treatment with 50 micrograms or less of antisense oligo[dN]/ml. These results suggested that antisense oligo[dN]s specific to the translational initiation sites of S, pre C, and P genes of HBV may have therapeutic potential for the suppression of HBV propagation in chronic HBV infected patients.

Cloning, Molecular↗
PubMed1995

Cementless total hip arthroplasty in patients with osteonecrosis of the femoral head.

The authors studied 61 patients (78 hips) who had avascular necrosis of the femoral head, seen in followup for an average of 7.2 years (range, 6-9 years) after they had primary cementless porous-coated total hip arthroplasty. This study was undertaken to determine whether cementless porous-coated prostheses have any merit over reported cemented total hip arthroplasty using contemporary techniques. The average age of the patients at the time of surgery was 48 years old (range, 20-73 years). The average preoperative hip score was 45.6 points (range, 28-75 points), which improved to 90.3 points (range, 34-100 points) at the 7.2-year followup examination. Sixteen of 78 arthroplasties failed in the period of followup, for an overall failure rate of 20.5%. Of the failed hips, 11 had femoral component loosening, 4 had femoral and acetabular component loosening, and 1 had excessive wear in the polyethylene liner. Four femoral components and 5 acetabular components were revised. Twenty-one of the 78 hips (27%) had an average of 5.6 mm (range, 3-9 mm) of wear in the polyethylene liner. Sixteen (20.5%) of 78 hips had acetabular and femoral periprosthetic osteolysis, and 22 (28.2%) hips had femoral periprosthetic osteolysis only. The cementless total hip arthroplasty in this series had a higher incidence of aseptic loosening of the femoral component, polyethylene liner wear, and periprosthetic osteolysis than that reported for cemented total hip arthroplasty using contemporary techniques.

Adult↗
PubMed1995

Osteolysis around cementless porous-coated anatomic knee prostheses.

We report the incidence of osteolysis in the femur, tibia, and patella of 44 consecutive patients (60 knees) who were followed for more than seven years after cementless knee arthroplasty with a Porous-Coated Anatomic prosthesis. The average age of the patients was 56.5 years (17 to 73); the operative diagnosis was osteoarthritis (33 knees), rheumatoid arthritis (17), tuberculous arthritis (7) and post-traumatic arthritis (3). All patellae were resurfaced. No femoral or tibial component was loose at the final follow-up examination. Thirty patellar components were loose of which six had been revised. Radiographs revealed osteolysis in 90% of the tibial plateaux and in 80% of the 30 intact patellar prostheses. No osteolysis was seen around any femoral component. In 50 knees (83%) the average wear of the polyethylene liner was 2.5 mm in the medial compartment and 1.7 mm in the lateral compartment. Four of 60 knees (6.7%) were revised for complete wear of the polyethylene liner of the tibial component. Fixation of the tibial and patellar components without cement fails to seal the interface between bone and prosthesis and allows the migration of polyethylene particulate debris which causes osteolysis.

Adolescent↗
PubMed1994

Identification of immunoreactive atrial natriuretic peptide in the gallbladder and bile juice of rabbit, pig and human.

The presence of immunoreactive atrial natriuretic peptide (irANP) in rabbit, pig and human gallbladders was investigated using radioimmunoassay and immunohistochemistry. Serial dilution curves of gallbladder tissue and bile juice extracts were paralleled to the standard curve of atriopeptin III. Gel filtration profiles of gallbladder tissue extracts showed a major peak corresponding to rat pro-ANP. The amounts of irANP in rabbit, pig and human gallbladders were 30.0 +/- 12.3 pg/mg (n = 7), 7.0 +/- 2.0 fg/mg (n = 7) and 17.7 +/- 2.0 fg/mg wet tissue (n = 8), respectively. Bile juice was also shown to contain irANP but with small molecular mass. The amounts of irANP in the rabbit, pig and human bile juice were 25.0 +/- 2.0 (n = 7) and 0.50 +/- 0.02 (n = 7), and 1.3 +/- 0.1 pg/ml (n = 8), respectively. The immunohistochemical staining of the rabbit gallbladder tissue revealed the presence of irANP in the luminal epithelium and smooth muscle layer. The amount of irANP was higher in the luminal epithelium than in the rest of the gallbladder tissue from rabbits (0.30 +/- 0.06 vs. 0.01 +/- 0.01 pg/microgram protein, P < 0.01). These findings suggest that ANP may be synthesized and stored in the gallbladder, and may have a role in the regulation of fluid balance and cystic motility.

Animals↗
PubMed1993

Isolation and kinetic characterization of the calmodulin methyltransferase from sheep brain.

The methyltransferase that catalyzes the trimethylation of lysine 115 in calmodulin has been purified from sheep brain. The enzyme is a monomer with an apparent molecular weight of 38,000 on the basis of gel filtration chromatography and SDS-polyacrylamide electrophoresis. In the presence of calcium the methyltransferase exhibited a Km of 100 nM for unmethylated calmodulin and a kcat of 0.0278 s-1. The enzyme was able to use calcium-depleted calmodulin as a substrate, albeit with less efficiency. The methylation of calcium-depleted calmodulin was inhibited by increases in ionic strength, whereas methylation of calcium-saturated calmodulin was not affected. This suggests a difference in the mode of interaction of calcium-saturated and calcium-depleted calmodulins with the enzyme. As with calmodulin's interactions with other calmodulin-dependent enzymes, the oxidation of the methionines of calmodulin by performic acid treatment decreases the ability of the methyltransferase to recognize and methylate calmodulin. A calmodulin-binding peptide based on the calmodulin-dependent protein kinase II sequence and the naphthalenesulfonamide W-7 inhibit the calmodulin methyltransferase-calmodulin interaction in a calcium-dependent manner. Removal of the NH2-terminal lobe (residues 1-77) does not affect the ability of the calmodulin methyltransferase to recognize and methylate lysine 115. Thus, the determinants for calmodulin methyltransferase binding reside solely in the COOH-terminal lobe of calmodulin. Further, structural features within this region, in particular, the hydrophobic cleft, that are manifested upon calcium binding may contribute to the interaction of calmodulin with the enzyme.

Amino Acid Sequence↗
PubMed1993

Purification and some properties of apurinic/apyrimidinic DNA endonucleases in rat liver.

1. Three kinds of apurinic/apyrimidinic (AP) DNA endonucleases, APcI, APcII, APcIII were purified from rat liver chromatin. 2. Molecular weights of APcI, APcII and APcIII were 30,000, 42,000 and 13,000 Da, which have isoelectric points of 7.2, 6.3 and 6.2, respectively. 3. Mg2+ was essential for the activities of these 3 enzymes, and sulfhydryl compounds (beta-mercaptoethanol) had a stimulatory effect on the enzyme activities while N-ethylmaleimide and HgCl2 inhibited the enzyme activity. 4. Km values of APcI, APcII and APcIII for AP site of DNA were 0.53, 0.27 and 0.36 microM, respectively, and AMP was the most potent inhibitor to these three enzymes among nucleotides tested.

Animals↗
PubMed1993

Immunoreactive atrial natriuretic peptides in the oocyte.

1. The presence and partial characterization of immunoreactive ANP (irANP) in eggs were investigated using high performance liquid chromatography (HPLC), immunohistochemistry and Northern-blot hybridization in mammalian and nonmammalian vertebrates. 2. Serial dilution curves of egg extracts from frogs and freshwater teleostean fishes (silver crusian carp and loach) were parallel to the standard curve of atriopeptin III. Rat oocytes also contained irANP (25-30 pg/egg). 3. The HPLC profile of irANP showed two main peaks corresponding to low and high molecular weight of irANP. 4. ANP mRNA was detected in the fish eggs. With immunohistochemical analysis of the rat ovarian follicles, this ANP-like material was localized mainly at the oocytes. 5. We, therefore, suggest that the vertebrate oocytes synthesize ANP and that the presence of ANP in the oocytes may be linked with the cell differentiation.

Animals↗