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Biomedical subjects

K Han

Publications and source records attributed to K Han.

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

Role of platelet-activating factor in pathogenesis of galactosamine-lipopolysaccharide-induced liver injury.

In an attempt to clarify the role of platelet-activating factor (PAF) in the pathogenesis of hepatic injury induced by galactosamine (GalN) plus lipopolysaccharide (LPS), effects of WEB 2086 (PAF receptor antagonist) on hepatic injury in vivo as well as on neutrophil adherence to hepatic endothelial cells in vitro have been investigated, as we have recently clarified the role of neutrophils in this experimental model of hepatic injury. Although an enhanced serum TNF-alpha level after GalN-LPS administration was not reduced by WEB 2086, hepatic injury and hepatic neutrophil accumulation in the liver after GalN-LPS administration were attenuated by WEB 2086. An in vitro study revealed that an enhanced neutrophil adhesion to hepatic endothelial cells by stimulation with the sera that were collected from the GalN-LPS-treated rats, was reduced in the presence of WEB 2086 in a dose-dependent manner. In addition, LPS, TNF-alpha, and PAF were found to enhance the neutrophil adherence to hepatic endothelial cells, which was reduced in the presence of WEB 2086. These results suggest that PAF play an important role in the GalN-LPS induced hepatic injury and that PAF receptor antagonist reduces the neutrophil adherence to hepatic endothelial cells in the liver.

Animals↗
PubMed1996

Chromosomal numerical aberrations in gastric carcinoma: analysis of eighteen cases using in situ hybridization.

Paraffin-embedded tumor cells of 18 cases of gastric carcinoma were hybridized with digoxigenin-labeled repetitive DNA probes specific for the centromeric regions of chromosomes X, Y, 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 18, and 20. All cases demonstrated numerical chromosomal aberrations. The most exciting aberration, polysomy (five or more copies) of several chromosomes, was found in all cases except a case of mucinous adenocarcinoma, which showed trisomy 9 as the sole chromosomal numerical aberration. In nine cases of tubular adenocarcinoma, poorly-differentiated polysomies of several chromosomes were the consistent numerical aberration and monosomy 7, 18(2 cases each), 10, and 17(1 case each) were also found. In moderately-differentiated tubular adenocarcinoma all three cases also showed polysomies of several chromosomes. The total number of extra chromosomes (polysomy was counted as 5 copies) was higher in the intestinal type (mean 20.9) than in the diffuse type (mean 14.1). Regional lymph node metastasis, vein invasion, or perineural invasion was not related to any specific chromosomal numerical aberration in gastric cancer. Chromosomes X, 1, 2, 3, 4, 15, 17, and 20 had extra copies especially polysomy in most cases. However, chromosomes 7 and 18 revealed monosomy in many cases (31.3% and 33.3% respectively, and chromosome 9 and 11 revealed trisomy in 35.7% and 75% each. Numerically, the most conserved chromosome in gastric cancer was chromosome 12 (62.5%). By flow cytometry, two diploidy and 8 aneuploidy cases with the DNA indices from 1.30 to 1.85 were found.

Adult↗
PubMed1996

Pseudoaneurysm of the anterior superficial temporal artery.

Pseudoaneurysm of the superficial temporal artery must be considered in the differential diagnosis of masses of the lateral forehead and temporal fossa. While the first reported case of a temporal artery aneurysm was reported by Thomas Bartholin in 1740, there is scant mention of this lesion in the plastic and maxillofacial surgical literature. Pseudoaneurysms can arise in the forehead and scalp as a result of blunt traumatic impingement of the superficial temporal artery against the calvarium. The anterior branch of the artery is most vulnerable, because in the lateral forehead it courses over the frontal osseous ridge in the galea aponeurotica formed by the fusion line of the deep and superficial temporalis muscle fascia. This dense fascial investment has a tethering effect in the gap between the temporalis and frontalis muscles and prevents the artery from displacing laterally in response to traumatic forces. A history of recent blunt trauma or surgery to the forehead, combined with a pulsatile bruit, should direct the physician to the diagnosis of pseudoaneurysm of the superficial temporal artery. Treatment is surgical resection of the involved segment without the need for reconstruction. This report includes a review of the literature and presents the first documented case of a bicycle helmet as the cause of a superficial temporal artery pseudoaneurysm.

Adult↗
PubMed1996

A custom-made nasal implant: prefabrication from curing of silicone adhesive.

When nasal augmentation is performed with implants fashioned from a piece of solid silicone block or commercially available prefabricated implants, the precise sculpturing of the ventral surface of the implant in order to conform to the convex contour of the nose is often difficult to achieve, increasing the possibility for malposition and extrusion. We devised two methods of making soft silicone elastomer implants from nasal cast models obtained from alginate impressions of patients' noses: type I, in which the implant is made from the curing of silicone adhesive that is spread on both sides of the sheet blueprint placed on the cast model, and type II, in which the implant is made only from the curing of silicone adhesive. Because these custom-made implants have a ventral surface of exact concave contour conforming to the convex surface of the nasal framework, they blend in nicely with the various configurations of the existing nasal framework and thus minimize malposition and extrusion. These implants also avoid having a prototype nose for everyone and are more cost-effective than commercially available implants.

Alginates↗
PubMed1996

In situ hybridization studies of cytomegalovirus and Epstein-Barr virus in reactive histiocytic hyperplasia with hemophagocytosis.

We studied 14 adult patients presenting with fever and cytopenia of the peripheral blood and histiocytic hyperplasia with hemophagocytosis (HHH) in the bone marrow regarding an association of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) by using in situ hybridization (ISH) and also evaluated the clinical and laboratory findings according to the encountered organisms. ISH using a CMV RNA probe demonstrated infected cells in 6 out of 14 cases (43%), and ISH using an EBV EBER RNA probe demonstrated infected nuclei in 5 out of the same 14 cases (36%) of HHH. No cases showed a positive reaction with both probes. Three cases showed a negative reaction with both probes. The mean age of all patients was 29 years; and that of the CMV-positive patients was 27 years and that of the EBV-positive patients was 36 years. Organomegaly was found in 3 out of 6 CMV-positive patients (1 hepatomegaly, 1 splenomegaly, 1 hepatosplenomegaly), and 4 out of 5 EBV-positive patients (lymphadenopathy in all 4 cases, hepatosplenomegaly in 2 cases). One of the CMV-positive case had acute myeloblastic leukemia, and 2 EBV-positive cases had underlying malignancy (1 Hodgkin's disease, 1 non-Hodgkin's lymphoma). Seven out of the 14 HHH cases (50%) died within several months after diagnosis. Nucleic acid hybridization methods can be used for the routine examination of the association of CMV or EBV.

Adult↗
PubMed1996

Bombesin specifically induces intracellular calcium mobilization via gastrin-releasing peptide receptors in human prostate cancer cells.

Bombesin and gastrin-releasing peptide (GRP) are potent neuropeptides expressed by prostate cancer neuroendocrine cells and are related to the progression of this malignancy. This study characterizes bombesin receptors in human prostate cancer cell lines (PC-3, DU-145, LNCaP) and assesses the in vitro effect of bombesin on signal transduction and cell proliferation. [125I]Tyr4-bombesin binding assays (37 degrees C) and Scatchard analyses revealed the presence of a single class of high-affinity receptors with similar Kd values (1.5, 1.1 and 3.6 x 10(-10) M in PC-3, DU-145 and LNCaP cells respectively) but with significant differences in the number of binding sites per cell (47.6, 1.5 and 0.1 x 10(3) in PC-3, DU-145 and LNCaP cells respectively). Molecular characterization of the binding sites performed in PC-3 cells by cross-linking experiments and SDS/PAGE revealed a single radioactive band of 85 kDa. To determine which of the three known bombesin receptor subtypes (GRP receptor (GRP-R), neuromedin B receptor, bombesin receptor subtype-3) were expressed in the cell lines, reverse transcription/PCR analysis of cellular RNA followed by hybridization with receptor-specific cDNA was performed. This revealed the presence of GRP-R transcript in all cell lines, while neither of the other two receptor transcripts were expressed. When intracellular calcium mobilization was measured by Fura-2/AM cell labeling and spectrofluorometric monitoring, bombesin (100 nM) induced rapid calcium mobilization in both PC-3 (> 200% of baseline) and DU-145 (> 100% of baseline) cells, but not in LNCaP cells. However, as measured by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay and [3H]thymidine incorporation, no growth modulation was observed with bombesin or bombesin receptor antagonist at various concentrations (0-500 nM). Our data indicate that bombesin is a potent inducer of signal transduction via GRP-R receptors in androgen-insensitive PC-3 and DU-145 prostate cancer cells. This suggests that the bombesin/GRP family of neuropeptides may play a regulatory role in the biology of androgen-independent prostate cancer.

3T3 Cells↗
PubMed1996

Interphase cytogenetics of non-Hodgkin's lymphoma using non-fluorescent in situ hybridization in paraffin embedded tissue.

Paraffin-embedded tissue samples from 30 cases of non-Hodgkin's lymphoma(NHL) and 10 of reactive hyperplasia, were processed for interphase cytogenetic chromosomal study. We performed non-fluorescent in situ hybridization(NFISH) using the enzymatic method with digoxigenin-labeled DNA centromeric probes for chromosome 7,12,18 and X, and a painting probe for chromosome 18. Chromosomal aberrations were observed in 27(90%) out of 30 cases of NHL. The most commonly observed numerical aberration was extracopy of X chromosome. There were some characteristic aberrations corresponding to each grade and group of NHL by International Working Formulation: In low grade NHL(9 cases), a third were associated with extracopy of chromosome 12, and disomy X was frequently found in small lymphocytic lymphoma(75%). With intermediate grade(16 cases), tetraploidy(25%), translocation of chromosome 18(25%), and extracopy of chromosome 18(19%) were characteristically associated. These results suggest that interphase NFISH is an easily performable method in retrograde cytogenetic study of archival materials. Some specifically correlated chromosomal aberrations corresponding to the histopathologic grades and groups could provide us more valuable information for determining pathologic diagnosis and assessing the clinical outcome of NHL.

Chromosome Aberrations↗
PubMed1995

Occurrence of antibody against rat hepatic sinusoidal endothelial cells in sera of patients with autoimmune hepatitis.

To determine whether an antibody against hepatic sinusoidal endothelial cells was present in sera of patients with autoimmune hepatitis (AIH) type 1, we measured the serum IgG bound to the glutaraldehyde-fixed cultured rat sinusoidal endothelial cells by enzyme-linked immunosorbent assay. IgG bound to the cells was detected significantly more in patients with autoimmune hepatitis type 1 (97.1%) than in those with primary biliary cirrhosis (13.0%), chronic hepatitis C (5.9%) or B (7.9%), or healthy controls (0%). IgG-F(ab')2 fragments from autoimmune hepatitis patients also bound to the cells, and this binding was observed after absorption of the fragments with rat hepatoma cells, but not after absorption with bovine carotid endothelial cells. Culture of sinusoidal endothelial cells in the presence of IgG from AIH patients significantly reduced the number of viable attached cells. In conclusion, anti-sinusoidal endothelial cell antibody occurred in the sera from patients with autoimmune hepatitis type 1.

Animals↗
PubMed1995

Oxidation and glucose conjugation of synthetic abietane diterpenes by Cunninghamella sp. II. Novel routes to the family of diterpenes from Tripterygium wilfordii.

Abietane diterpenes from the perennial herb, Tripterygium wilfordii, have been shown to possess antiinflammatory activity. To obtain novel analogues of these diterpenes, two synthetic diterpenes, isotriptophenolide [1] (12,19-dihydroxy-18(4-->3)abeo-abieta-3,8,11,13-tetraen++ +-18-oic acid lactone) and triptophenolide [3] (14,19-dihydroxy-18(4-->3)abeo-abieta-3,8,11,13-tetraen++ +-18-oic acid lactone) were incubated with the filamentous fungi, Cunningbamella echinulata and C. elegans. The structures of the metabolites were then determined by spectroscopic methods. Both species of Cunninghamella glucosidated 1 at C-12 to yield 2. When incubated with triptophenolide [3], C. elegans and C. echinulata produced hydroxylated [6] and glucosylated [7] metabolites. In addition to B-ring hydroxylation, aromatic hydroxylation at ring C was also observed. Both species hydroxylated 3 to yield the dihydrodiol 4 which autooxidized to the quinone 5.

Biotransformation↗
PubMed1995

[Appropriation of time for professional staff and appropriation of costs for services, education and research at a major teaching hospital].

Cost analysis of hospital graduate medical education (GME) cannot follow standard accounting procedure because most of the services, teaching and research activities involved are performed simultaneously. This paper surveys work time allocation and analyzes the budgetary appropriation of a major teaching hospital in Taiwan, ROC based on answers given in a specially designed questionnaire. Percentages of working time used for services, teaching, research by the 2206 professionals at the hospital were 84.0%, 10.3% and 5.7% respectively; for the 776 physicians the figures were 64.1%, 22.7% and 13.2% respectively; GME represented a 12.22% share of the operation budget. In view of the fact that the IRB (Intern-Resident/Bed) ratio of the hospital reaches a high of 45%, GME investment is apparently insufficient. To obtain a reasonable ratio of teaching activities, hospital physicians expressed the opinion that the GME expenditure rate should be at least 18.95%. The Labor Insurance Plan, currently the biggest of its kind in this country, pays 3% of GME expenses to all hospitals. This payment neglects the different teaching load in different hospitals.

Cost Allocation↗
PubMed1995

Prostanoid secretion by rat hepatic sinusoidal endothelial cells and its regulation by exogenous adenosine triphosphate.

We investigated the secretory profiles of prostanoids in two types of nonparenchymal cell from the rat liver, sinusoidal endothelial cells and Kupffer cells, in primary culture both under basal conditions and after stimulation with adenine nucleotides. Prostaglandin (PG) E2 was the main prostanoid secreted by both types of hepatic nonparenchymal cell in the basal and adenosine triphosphate (ATP)-stimulated states. Time- and concentration-dependent effects of ATP-mediated PGE2 secretion were noted in sinusoidal endothelial cells, whereas the profile of the relative potencies of individual nucleotides was consistent with the presence of P2y and P1 purinergic receptors. In Kupffer cells, the regulation of prostanoid secretion by adenine nucleotides was essentially the same as that in sinusoidal endothelial cells except that adenosine did not stimulate prostanoid secretion and that prostanoid secretion differed somewhat; Kupffer cells secreted relatively more PGF2 alpha and less 6-keto-PGF1 alpha than sinusoidal endothelial cells in the presence of ATP, suggesting the presence of only P2y receptors. In summary, PGE2 is the main prostanoid secreted by hepatic nonparenchymal cells and its secretion may be stimulated by adenine nucleotides and adenosine.

Adenine Nucleotides↗
PubMed1995

A distributed, scalable, community care network architecture for wide-area electronic patient records: modeling and simulation.

Principal systems issues relative to computerizing patient medical records that are yet to be addressed in the scientific literature include (1) the characteristics of networks, i.e. bandwidth and capacity, and their impact on the performance of the system, (2) the architecture and the underlying algorithm of the system, (3) the location and migration of medical records, (4) scalability of the system, and (5) the nature of the performance variation under heavy and light use of the network. Key parameters that affect performance include the number of patients, doctors, frequency of patient visits, and the number of electronic queries and record entries initiated during a patient-doctor interaction episode. This paper presents AMPReD, a Distributed, Scalable, Community Care Network Architecture that aims to provide Real-Time Access to Geographically-Dispersed Patient Medical Records. The AMPReD model includes stationary hospitals and medical clinics, mobile clinics, migrating doctors as well as patients, the communications network, and the patient medical record database. AMPReD's goals include (1) the accurate modeling of the propagation of medical records and (2) providing real-time access to patient medical records from anywhere in the system. To achieve these goals, an asynchronous, distributed algorithm must be developed that achieves concurrent access of multiple, autonomous databases. AMPReD is modeled and simulated for a representative community care network on a network of workstations configured as a loosely-coupled parallel processor, for different parametric combinations of number of doctors, patients, and number of queries or record entries generated corresponding to every patient-doctor interaction episode. AMPReD defines and obtains key performance measures including the idle times of the doctors, patient waiting times, the access times of queries as functions of their sizes, and the growth of the databases. In addition, AMPReD also measures the deviation of the actual time required for a patient-doctor interaction episode from the scheduled interaction interval, as a function of the network load. For the representative system selected, performance measures indicate that the network, utilizing 1/2T1 links, and the database system poses no bottleneck to the system even where the number of doctors and patients within a 30 minute interval are chosen at 192 and 200 respectively. A T1 is a standard, digital, transmission link that is rated at 1.44Mbits/sec.

Algorithms↗
PubMed1994

cAMP, ethanol, and CO2 production with the addition of D-glucose anomer to starved yeast cells.

cAMP, ethanol, and CO2 production in starved yeast cells after the addition of D-glucose anomer was measured and compared over a wide range of anomer concentrations. At 1.0 g/l or higher concentrations, the addition of beta-D-glucose resulted in a higher cAMP peak. beta-D-glucose was more rapidly metabolized to ethanol and CO2 than alpha-D-glucose, although there was no notable difference in the uptake rates of the two anomers. At 0.4 g/l D-glucose anomer, the differences in cAMP and ethanol production rates for the two anomers were not significant. At 0.2 g/l D-glucose anomer or lower concentrations, ethanol production with alpha-D-glucose was higher than that with beta-D-glucose. The uptake rate of alpha-D-glucose was higher than that of beta-D-glucose at this low concentration.

Carbon Dioxide↗
PubMed1994

Tyrosinase production in recombinant E. coli containing trp promoter and ubiquitin sequence.

We have successfully expressed the active tyrosinase of Streptomyces antibioticus in Escherichia coli under the control of the trp promoter by fusing the sequence to the ORF438 gene. Because our attempt to connect the polycistronic gene of ORF438 and tyrosinase directly to the trp promoter of E. coli resulted in the expression of functionally inactive tyrosinase, we decided to fuse the COOH-terminus of ubiquitin sequence to the NH2-terminus of ORF438. Ubiquitin fusion has been shown to augment the yield of cloned gene products in E. coli by increasing the stability or translational efficiency of the fusion proteins. As a result, E. coli transformants harboring a plasmid pTRUBF that contains the ubiquitin-fused ORF438 and the tyrosinase gene produced the strong black pigment of melanin. About 300 units of tyrosinase per liter of batch culture were detected when cultivated in M9 medium containing casamino acids, L-tyrosine, and copper supplements. The black pigment, however, was not seen when grown in LB medium, suggesting that the trp promoter is well regulated. When recombinant E. coli cells grown in LB medium were transferred to a tryptophan-deficient minimal medium with phenol, we observed that phenol was removed from the solution, and the color of the medium turned black. This is due to the fact that the tyrosinase has polyphenol oxidase properties. We expect to use this recombinant E. coli for the waste treatment of phenolic compounds.

Base Sequence↗
PubMed1994

Role of polymorphonuclear leukocytes in galactosamine hepatitis: mechanism of adherence to hepatic endothelial cells.

To investigate the role of polymorphonuclear leukocytes in galactosamine-induced hepatic injury, we injected rats intraperitoneally with antiserum against rat polymorphonuclear leukocytes to deplete circulating neutrophils, then administered galactosamine plus lipopolysaccharide. Polymorphonuclear leukocytes in the hepatic sinusoids were increased after administration of galactosamine plus lipopolysaccharide, whereas pretreatment with the antiserum decreased the number of circulating leukocytes and reduced the mortality and the severity of hepatic injury. Serum collected 1 hr after galactosamine/lipopolysaccharide treatment enhanced in vitro polymorphonuclear leukocyte adherence to hepatic endothelial cells and induced leukocyte superoxide production. Intercellular adhesion molecule-1 expression on hepatic endothelial cells was also enhanced after stimulation with the serum. Polymorphonuclear leukocyte adhesion was partially inhibited by an antibody against tumor necrosis factor-alpha but not by superoxide dismutase. These results suggest that polymorphonuclear leukocytes play an important role in galactosamine-induced hepatic injury and that the accumulation and activation of leukocytes, as well as the enhanced expression of adhesion molecules on hepatic endothelial cells, can be induced by biologically active mediators such as tumor necrosis factor-alpha. In addition, prostaglandins E1 and E2 lessened the enhanced adherence of polymorphonuclear leukocytes and thus contributed to protection against hepatic injury.

Alprostadil↗
PubMed1994

Implantation of PNS graft inhibits the induction of neuronal nitric oxide synthase and enhances the survival of spinal motoneurons following root avulsion.

In a spinal root injury model, our previous studies have shown that induction of nitric oxide synthase (NOS) appears only in spinal motoneurons of the root-avulsed segment in which significant motoneuron loss occurs but not in those of the distal root-axotomized segment (root axotomy 5-10 mm from the spinal cord) in which most motoneurons survive the injury. One hypothesis for the different response of motoneurons to root avulsion and distal root axotomy is that neurotrophic factors produced by the remaining peripheral nervous system (PNS) component are available for the distally axotomized motoneurons but are not available following avulsion. This hypothesis is tested in the present study by implantation of a PNS graft following the root avulsion. Results of the present study show that implantation of a PNS graft significantly enhances the survival of motoneurons following avulsion. Expression of NOS due to avulsion injury is completely inhibited in all motoneurons that regrow into the PNS graft. These results indicate that induction of NOS in avulsed motoneurons may result from the deprivation of neurotrophic factors produced by the PNS component, and the survival promoting effects of neurotrophic factors may be achieved by modifying certain cellular molecules such as NOS.

Amino Acid Oxidoreductases↗