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Biomedical subjects

S H Han

Publications and source records attributed to S H Han.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Monoclonal antibodies against antigens expressed on human hepatocellular carcinoma cells.

Monoclonal antibodies with selectivity for human hepatoma cell lines were produced by immunizing BALB/c mice with human hepatoma cell lines, HA22T/VGH or Hep 3B, and fusing sensitized mouse spleen cells with mouse myeloma cells. Two monoclonal antibodies recognizing antigens present only on human hepatoma cell lines were investigated. The monoclonal antibody IB1 was found to react with 3 of 9 hepatoma cell lines. Monoclonal antibody 9B2 reacted with all nine hepatoma cell lines. None of the other 20 cell lines tested was bound by IB1 and 9B2. The immunoperoxidase staining of monoclonal antibodies on frozen sections of paired hepatoma and normal liver tissues from the same individuals were studied. Antibody IB1 reacted with 3 of 13 hepatoma tissues, but with none of the normal liver and other tissues, and antibody 9B2 was reactive with antigens appearing on the bile canalicular domain of hepatoma and normal liver tissues. The antibody 9B2 stained no normal tissues with the exception of proximal tubules of kidney. Radioimmunoprecipitation tests identified two antigens reacting with 9B2. The major antigen had an apparent molecular weight of 140,000 and a minor one of 130,000. Therefore, antibody IB1 seems to be specific for antigens present on a group of human hepatoma cells and may be useful for classification and diagnosis of human hepatomas. Antibody 9B2 is quite specific to human liver cells and may be used to provide clues for the characterization of tumor cell lines, identification of metastatic tumors with hepatocytic origin, and study of the structure and function of bile canaliculi.

Animals↗
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Atypical signaling defects prevent IL-2 gene expression in lpr/lpr CD4-CD8- cells.

T cells with CD4-CD8- (double negative, DN) phenotype in MRL-lpr/lpr mouse serve as a model to establish the correlation between the extremely low IL-2 gene expression and the specific signaling inactivation. The extent of nonresponsiveness in lpr DN cells was distinctive in several unusual defects. First, the poor IL-2 production in lpr DN cells could not be restored by supplement of signals known to augment IL-2 response in normal T cells. Second, the activations of both mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK) were attenuated in lpr DN cells upon direct activation by TPA/A23187. Third, IL-2 mRNA was degraded much faster in lpr DN cells than that in normal T cells. Fourth, of the four major transcriptional elements on IL-2 promoter, only AP-1 and nuclear factor of activated T cells (NFAT)-binding activities were suppressed in lpr DN T cells. Altogether, these results suggest that an extremely low level of IL-2 production in lpr DN T cells was due to both the increased instability of mRNA and the reduced activation of IL-2 gene promoter, the latter defect could be attributed to the inactivation of AP-1 and NF-AT as well as the poor activation of the upstream MAP kinase and JNK.

Animals↗
PubMedDate not supplied

An Sp1 binding site involves the transcription of the Fas ligand gene induced by PMA and ionomycin in Jurkat cells.

The transcriptional regulation of the Fas ligand (FasL) gene in Jurkat cells was investigated. We demonstrated that an Sp1 binding site, located between -280 and -275 bp relative to the translational start site (+1) of the FasL gene, was important for the transcription of the FasL gene by deletion and mutation analysis in Jurkat cells after phorbol 12-myristate 13-acetate (PMA) and ionomycin treatment. Nuclear extract of Jurkat cells formed complexes with the oligonucleotides bearing the Sp1 site within -280 to -275 of the FasL promoter. Apart from the constitutive complexes, a new complex was observed after PMA and ionomycin stimulation. Plasmid containing the Sp1 site sequence with site-directed mutation reduced the FasL promoter activity in driving the expression of reporter luciferase gene expression in transfected Jurkat cells after PMA and ionomycin stimulation. The binding of activated Jurkat cell nuclear extract to the mutated Sp1 binding site of the FasL promoter was ablated. In addition, the oligomer containing the Sp1 site of the FasL promoter could compete with oligomer with conserved Sp1 binding sequence in nuclear protein binding of activated Jurkat cells. The data presented in this study suggest that the transactivation of the FasL promoter via the Sp1 binding sequence (-280 to -275) involves the PMA- and ionomycin-induced expression of the FasL gene.

Binding Sites↗
PubMedDate not supplied

The mechanisms of the inhibitory effects of liver extract on lymphocyte proliferation. III. The effects of arginase on DNA polymerase activities.

The incorporation of labeled precursors into DNA, RNA and protein in phytohaemagglutinin (PHA)-prestimulated human lymphocytes was maximally inhibited by liver extract (LEx) or arginase at 24 h. The activities of DNA polymerase alpha, beta and gamma were less inhibitable by these agents than was [3H]thymidine incorporation. The inhibition of DNA, RNA and protein syntheses by either LEx or arginase is probably due to arginine depletion by arginase activity, since their syntheses were similarly inhibited when cultured in an arginine-free medium in the absence of arginase. These results indicate that arginase nonspecifically inhibits the activities of DNA polymerase. The inhibition is probably due to arginine depletion.

Animals↗
PubMedDate not supplied

Effect of shear stress on fibrinogen adsorption and its conformational change.

The composition and molecular organization of adsorbed protein films are strongly correlated with thrombogenesis on artificial surfaces. In particular, the antibody-detectable (that is, conformationally intact) bound fibrinogen, but not that the total amount of adsorbed fibrinogen, is correlated with platelet reactivity. In this work, the authors quantified the adsorbed plasma protein distribution inside the left ventricular assist device. They also evaluated the effect of wall shear stress on protein adsorption and conformational change of adsorbed fibrinogen. Conformational change of adsorbed fibrinogen was measured by exposing the fibrinogen preadsorbed polyurethane to three anti-fibrinogen monoclonal antibodies; the 134B-29 detectable alpha 566-580 domain of fibrinogen was increased with increasing concentration of adsorbed fibrinogen, whereas the other two fibrinogen domains were almost saturated when increasing the concentration of adsorbed fibrinogen. The adsorbed amounts of total fibrinogen and monoclonal antibody detectable fibrinogen was decreased with increasing shear rate. Results of in vivo plasma protein adsorption on polyurethane surfaces disclosed that the adsorbed amount of fibrinogen, as well as albumin and globulin, was also decreased with increasing shear rate. In conclusion, less protein was adsorbed in the higher shear region and the effect of shear level on fibrinogen adsorption and its conformational change was strongly dependent upon the surface characteristics of the biomaterials. The monoclonal antibody 134B-29 against the 566-580 domain of fibrinogen was the most reactive with the fibrinogen adsorbed on polyurethane surfaces in this experiment.

Adsorption↗
PubMedDate not supplied

Efficacy of prophylactic ondansetron in a patient-controlled analgesia environment.

We conducted a prospective, randomized, double-blind, placebo-controlled trial to examine the efficacy of prophylactic ondansetron on post-operative nausea and vomiting (PONV) during opioid patient-controlled analgesia (PCA). In total, 374 patients using opioid PCA, but otherwise considered to be low risk for PONV, were randomly allocated to ondansetron (4 mg given intravenously and 16 mg added into the PCA pump) or saline (control group). PONV was evaluated in terms of nausea graded on a visual analogue scale, and the number of patients who experienced emetic episodes or needed rescue anti-emetics in the 48-h post-operative period. Patient satisfaction for PCA was scored at the end of the evaluation period. The only difference between the two groups was the higher number of headaches in the ondansetron group. In patients using opioid PCA, but with no other high risk factors for PONV, prophylactic ondansetron does not have any clinical benefit.

Aged↗
PubMedDate not supplied

Comparison of central venous catheterization sites in infants.

This study aimed to compare the rates of success and complications between different sites of central venous catheterization in infants. A total of 272 infants were randomized to four groups: right subclavian group (G-RSCV), right internal jugular group (G-RIJV), left subclavian group (G-LSCV) and left internal jugular vein group (G-LIJV). In 77.2% of the patients, we successfully introduced a catheter at the first attempt. The rate of successful catheter placement was highest in the and LSCV 55.9%). With regard to complications, the rate of arterial puncture, guide wire advancement failure and malpositioning of the catheter were all significantly more frequent during SCV catheterization (SCV versus IJV: 10.1% versus 2.1%, 12.4% versus 0% and 13.4% versus 0.6%, respectively). Our results imply that IJV, especially RIJV, should be the first choice for central venous catheterization in infants.

Catheterization, Central Venous↗
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The effect of gynaecological laparoscopic surgery on cerebral oxygenation.

During gynaecological laparoscopic surgery, alterations in cerebral blood flow and intracranial pressure are frequently reported. These changes affect cerebral perfusion pressure and thus may affect cerebral oxygenation. In this prospective study, the effect of gynaecological laparoscopic surgery on cerebral oxygenation was examined by following the changes in regional cerebral oxygen saturation (rSo2). Twenty-four female patients were enrolled. The mean rSo2 was 65.5 +/- 5.4% at baseline before surgery, 60.8 +/- 5.6% when the patient was placed in the Trendelenburg position, 57.1 +/- 9.3% after creation of pneumoperitoneum, and 64.0 +/- 7.3% after the completion of surgery. During the period of pneumoperitoneum, rSo2 fell below 50% in two hypercapnic patients. In comparison with baseline, rSo2 declined significantly in the Trendelenburg position. The creation of pneumoperitoneum itself did not decrease the average rSo2 value further unless the patients were hypercapnic.

Adult↗
PubMedDate not supplied

An experimental study of the antitumour effect of bleomycin hydrochloride microcapsules.

The controlled release behaviour of bleomycin hydrochloride microcapsules was investigated by an in vitro dissolution method and an in vivo antitumour test. Bleomycin hydrochloride microcapsules prepared using the highest cooling rate exhibited sustained release characteristics and its release rate obeyed a nearly zero order release kinetics. Microcapsules containing bleomycin hydrochloride were locally injected into the solid tumour of uterine cervix carcinoma bearing nude mice. Tumour growth was markedly inhibited by treatment using bleomycin hydrochloride microcapsules compared to the control group and the group receiving direct local administration of bleomycin hydrochloride. No significant differences in the changes of body weight after treatment were found between the control group and the treated group. These results suggest that controlled release microcapsules may be applicable as a drug carrier for delivery of antitumour agents in cancer chemotherapy.

Animals↗
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Effect of botulinum toxin A chemodenervation in sensory strabismus.

PURPOSE: To study the effect of botulinum toxin type A chemodenervation in sensory strabismus. METHODS: Twelve patients with sensory strabismus were treated with an injection of botulinum toxin type A (Botox; Allergan, Irvine, Calif). Botulinum toxin type A was diluted with 0.9% sodium chloride without preservative at a dose that ranged from 1.25-5 U. A Teflon-coated needle electrode was inserted into the medial rectus muscle in cases of esotropia and into the lateral rectus muscle in cases of exotropia. Four patients were treated with > or =2 injections of botulinum toxin type A. Changes in the angle of strabismus and related complications were followed for >6 months postinjection. RESULTS: The mean deviation before injection was 33.8 prism diopters (delta) and the mean corrective effect on the deviation was 72.8% after injection in patients with sensory strabismus. The final deviation in 9 patients was <10 delta. Complications were hypertropia in 3 (25%) patients and conjunctival hemorrhage in 1 (8.3%) patient. CONCLUSION: Botulinum toxin type A is likely to prevent muscle contracture and affect muscle and neuronal tissues. This study on the effects of sensory strabismus with botulinum toxin type A injection suggests it has the potential to replace surgery or be used as an adjuvant therapy.

Adult↗
PubMedDate not supplied

The role of functional MR imaging in patients with ischemia in the visual cortex.

BACKGROUND AND PURPOSE: Functional MR (fMR) imaging is based on changes in regional blood flow. The purpose of this study was to evaluate the role of fMR imaging for detection of a vascular compromised status in the occipital lobe in patients with ischemia in the visual cortex. METHODS: We performed fMR imaging in seven control subjects and seven patients with symptoms and signs of visual cortical transient ischemia and/or infarct. fMR imaging was performed using a gradient-echo sequence with the 2D fast low-angle shot technique. An axial slice including both visual cortices was selected, and stimulation of the visual cortex was performed using a red photostimulator. The number of activated pixels in each primary visual cortex area were counted and an asymmetry ratio [AR (%) = 100 x (R-L)/(R+L)/2] was calculated. Patients and control subjects underwent visual field examination, conventional MR imaging, and vascular imaging (MR angiography in all patients and control subjects, conventional catheter angiography in two patients). fMR imaging results were compared with the results of a visual field examination, conventional MR imaging, and vascular imaging. RESULTS: fMR imaging of the patients showed significant activation asymmetry (P <.05) compared with that of control subjects. Vascular abnormalities in the posterior circulation were found in all seven patients. By conventional MR imaging, five patients were found to have infarction in the occipital lobe and the remaining two patients showed no abnormality. In visual field examination, six of the seven patients showed homonymous hemi- or quadrantanopsia suggesting postchiasmic abnormalities, and the remaining patient had normal findings. fMR imaging showed decreased activity in the visual cortices corresponding to vascular abnormalities (seven of seven patients), permanent infarction (five of seven patients), or visual field defect (six of seven patients). Two patients with normal conventional MR imaging had vascular lesions in the posterior circulation, and fMR imaging showed decreased activity in the corresponding visual cortices. One patient with normal visual field examination had multifocal stenosis in the posterior cerebral artery without infarction, and fMR imaging showed decreased activity in the corresponding visual cortex. CONCLUSION: fMR imaging of the visual cortex may be a sensitive method for the detection of vascular-compromised status in the occipital lobe.

Adult↗
PubMedDate not supplied

Investigation of jewelry powders radiating far-infrared rays and the biological effects on human skin.

Far-infrared rays have certain kinds of effects on the human body, especially on skin, blood circulation, and skin cell vitalizing. Some jewelry powders radiate far-infrared rays. Jade has powerful far-infrared ray radiation, and tourmaline has pyroelectric and piezoelectric properties and radiated far-infrared rays. The jewelry powders (fine powdered jade and tourmaline powders) were screened by far-infrared rays for radiation properties and tested for the effects of far-infrared rays on the human skin by temperature observation using an infrared thermal analyzer.

Adult↗