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Biomedical subjects

H Ohki

Publications and source records attributed to H Ohki.

At least 37 records · Page 2Linked to original sources
PubMed1995

Glomus tumor of the upper lip.

A case of glomus tumor of the upper lip in a 57-year-old Japanese male is described. The patient had a tender swelling of the upper lip, and this was completely excised. The lesion was found to be encapsulated by fibrous connective tissue and composed of blood capillaries surrounded by sheets of epitheloid cells. Immunohistochemical examination revealed that the neoplastic cells were positive for S-100 protein, vimentin, desmin and actin. Although the endothelial cells of blood capillaries in the tumor tissue were positive for factor VIII, no reaction product was found in the tumor cells. These results suggested that the tumor cells had characteristics of smooth muscle cells.

Actins↗
PubMed1995

Serum levels of soluble interleukin-2 receptor in chronic hepatitis C treated with interferon-alpha.

BACKGROUND: Serum levels of soluble interleukin-2 receptor (sIL-2R) seem to serve as a marker for the activation of T lymphocytes. The aim of this study was to evaluate the clinical significance of such levels in patients with chronic hepatitis C (CHC) treated with interferon. METHODS: We measured serum levels of sIL-2R in 37 patients with CHC before and after treatment with recombinant interferon-alpha. Serum receptor levels were then compared with the response of the hepatitis C virus (HCV)-RNA level in serum after interferon. RESULTS: Receptor levels were significantly higher in the patients with chronic persistent hepatitis and chronic active hepatitis than in normal controls (p < 0.01). There was a weak correlation between serum sIL-2R and alanine aminotransferase (ALAT) levels (r = 0.14, p = 0.010). Patients were then classified into three groups on the basis of the effect of interferon treatment on HCV-RNA levels in serum: sustained response (SR; n = 21), non-sustained response (NSR; n = 14), and nonresponse (NR; n = 2). Before and during interferon treatment the serum sIL-2R level remained increased in the SR group and in the combined groups with NSR or NR. However, after interferon was withdrawn, the serum sIL-2R decreased in the SR group but remained significantly increased in the combined response group (p < 0.01-0.05). CONCLUSION: This finding seems to reflect the disappearance of HCV-RNA from the serum of the patients with an SR, and monitoring of sIL-2R levels may therefore be of value as an adjunct to the measurement of serum ALAT and HCV-RNA in evaluating the response to the interferon therapy for CHC.

Adult↗
PubMed1994

Retreatment of chronic hepatitis C with interferon.

OBJECTIVE: We analyzed the retreatment of chronic hepatitis C with interferon to get the standpoint for the selection of patients to receive it. METHODS: A complete response was defined as continuous normalization of the serum alanine aminotransferase (ALT) level and continuous disappearance of serum hepatitis C virus RNA (HCV-RNA) during interferon administration and more than 6 months after. Patients without complete response were classified as noncomplete responders. From August 1990 to May 1993, we retreated 23 noncomplete responders on initial treatment with interferon and studied the factors that alter the effectiveness. RESULTS: Complete response was achieved in eight (34.8%) patients; the other 15 patients did not achieve this degree of response. Three patients were of genotype II and five were of genotype III in these eight complete responders. All complete responders were patients with relapse who had had normalized serum ALT levels during the initial administration and undetectable HCV-RNA at the end of the period. No patient who failed to achieve normalization of the serum ALT level on initial treatment achieved a complete response on retreatment. HCV-RNA concentrations before retreatment were significantly less than before initial treatment in the eight complete responders. CONCLUSION: Interferon retreatment of patients who do not achieve a complete response may be effective in relapsed cases with undetectable HCV-RNA at the end of initial treatment. Selection of patients to receive interferon retreatment requires careful review and consideration of genotype, HCV-RNA concentration, and the clinical response on initial treatment.

Alanine Transaminase↗
PubMed1992

Optically accessible microchannels formed in a single-crystal silicon substrate for studies of blood rheology.

An attempt to use microgrooves as blood flow channels in single-crystal silicon is described. Grooves were formed in the (100) crystalline surface by means of photolithography and orientation-dependent etching. This substrate surface was tightly covered with an optically flat glass plate to prevent leakage. This structure was used to microscopically observe flow behavior of blood cells. As a first design of such a cell-flow apparatus, many parallel same-size channels of relatively short length (equivalent diameter 6 microns, length 14.4 microns, number 2600) have been produced to simultaneously measure the total volume flow rate of blood under constant suction. Despite differences in cross-sectional shape and length, the ratio of blood flow velocity to pressure gradient in the channels was comparable with estimates for capillary vessels in vivo. Activated white blood cells blocked the channels, while aggregations of red blood cells showed unexpectedly small resistance to channel transit.

Blood Circulation↗
PubMed1992

Hydrops fetalis caused by fetal Kasabach-Merritt syndrome.

There have been only 2 previous reports of nonimmunologic hydrops fetalis (NIHF) caused by fetal Kasabach-Merritt syndrome, both of which were pathological studies. This is the first clinical case report of NIHF due to fetal Kasabach-Merritt syndrome that was prenatally diagnosed by sonography, computerized tomography, and percutaneous umbilical blood sampling.

Adult↗
PubMed1992

Large scale production and characterization of lyophilized pyridoxalated hemoglobin-polyoxyethylene (PHP).

Lyophilized PHP as an oxygen carrier is prepared from outdated red cell and dicarboxymethylated polyoxyethylene. In order to apply PHP for a clinical use, a large scale production of high quality PHP has been studied. We have set up a 20 L scale production flow of PHP88. The product was tested to confirm the quality and lot-to-lot consistency. The blood group specific materials were weakly positive in stroma-free hemoglobin (SFH), however, were found negative in the PHP of this scale. The amount of phosphatidylethanolamine (PE) in purified SFH and PHP88 reconstituted solution was 0.19 +/- 0.04 and 0.03 +/- 0.01 ppm, respectively. Contamination of viruses such as HBV and Non A non B hepatitis virus could not be observed in the final product. Elimination and inactivation of HIV was validated through a spike test. The characterizations of the final products in 20 L scale were done through MW, P50, Hill coefficient, viscosity, and molecular weight distribution by SDS-PAGE and batch to batch consistency was also confirmed. The results show that production process is appropriate to eliminate the blood group materials, PE and virus, and produce PHP of high quality. Lyophilized PHP88 can be produced by addition of maltose and can be stored over 1 year.

Biotechnology↗
PubMed1991

Cholestasis induced by lithocholate and its glucuronide: their biliary excretion and metabolism.

We studied the effects of the infusion of lithocholate and lithocholate-3-sulfate and 3-glucuronide in rats (0.29 mumol/min per 100 g body weight for 40 min) on bile flow, together with their biliary excretion and metabolism. Lithocholate-glucuronide had a higher cholestatic effect than lithocholate, whereas lithocholate-sulfate had almost no effect on bile flow. Lithocholate was mainly converted to taurine or glucuronide conjugates in the bile, serum and liver and hydroxylation of the tauro-conjugate proceeded. Lithocholate-sulfate was almost completely excreted in the bile, mainly as tauro-conjugate. Lithocholate-glucuronide was excreted in bile almost without conjugation, while some taurine conjugation occurred in the serum and liver. These results suggest that the poor biotransformation of lithocholate-glucuronide is related to its higher cholestatic potency than lithocholate.

Alanine Transaminase↗
PubMed1990

Evidence for peripheral mechanisms inducing tissue tolerance during ontogeny.

Tissue grafts from a histoincompatible donor of the same developmental stage were introduced into an early chick embryo host in order to probe the immune response to the graft after birth, when the host has reached immune maturity. Limb buds from B4 or B12 chicken strains were grafted in situ on (B15 x B21)F1 recipients that were allowed to hatch. The grafted wing grew normally and was tolerated in a nearly perfect way during the host's lifetime, although reversible rejection crises severely affected the fundamentally healthy state of the grafted tissues. Skin grafts of the same major histocompatibility complex haplotype as the wing were performed on the adult wing-chimera and were permanently tolerated. In contrast, host peripheral blood lymphocytes maintained their capacity to proliferate against donor cells in the mixed lymphocyte reaction. These results, while showing that in vitro and in vivo tolerance are separable phenomena, suggest the existence of a peripheral mechanism inducing tolerance to self that complements the elimination of self-reactive clones by the thymus.

Animals↗
PubMed1989

Further characterization of the binding of plasminogen to heparin: evidence for the involvement of lysine residues.

We have previously demonstrated that the heparin-binding site of plasminogen is located in Val442-plasminogen region (kringle 5 domain plus light (B) chain) (Soeda, S., Kakiki, M., Shimeno, H., and Nagamatsu, A. (1987) Biochim. Biophys. Acta 916, 279-287). The chemical modification of Val442-plasminogen with a lysine reagent, pyridoxal 5'-phosphate (PLP), and sodium borohydride resulted in the incorporation of 8-10 PLP moieties per molecule of the zymogen. This PLP-labeled zymogen had no affinity for a heparin-Sepharose column, whereas the non-labeled one bound to the column. Modification in the presence of heparin decreased the extent of labeling by 1-2 mol of PLP per mol of Val442-plasminogen. To further examine the binding site of plasminogen to heparin, functionally active A and B chains were separated from Lys-plasmin after mild reduction and S-carboxymethylation. Only B chain possessed affinity for heparin-Sepharose. Furthermore, plasmin(ogen) bound to heparin was protected from alpha 2-antiplasmin inhibition. These results indicate that one or two lysine residues located in the catalytic region (B chain) of plasmin(ogen) are essential to heparin binding, and that the binding of plasminogen to heparin or heparin-like substance in extracellular matrix environments may be important for the localization and activation of plasminogen and for the prolongation of the resultant plasmin activity.

Binding Sites↗
PubMed1989

Comparison of biliary excretion and metabolism of lithocholic acid and its sulfate and glucuronide conjugates in rats.

Biliary excretion and biotransformation of tracer doses of [14C]lithocholic acid and its sulfate and glucuronide intravenously injected into bile-drainaged rats were compared. Biliary excretion efficiency was in the order of unconjugate sulfate glucuronide and all conjugates were completely excreted into bile within 60 min after injection. Only tracer doses of radioactivity were found in the liver and urine. About 90% of radiolabeled bile acids in bile were conjugated with taurine immediately after injection of lithocholic acid, whereas lithocholic acid-glucuronide was only partly conjugated with taurine all the time (less than 6%) and excreted into bile mainly as native compound. In the first 10 min, 66% of lithocholic acid-sulfate was conjugated with taurine and it gradually proceeded up to 87%. Hydroxylation at C-6 and C-7 positions of lithocholic acid proceeded time-dependently up to 45%. No hydroxylation was observed with lithocholic acid-sulfate or glucuronide. Differences of biliary excretion rate of these conjugates may be one of the reasons for the delayed decrease of sulfated and glucuronidated bile acids in serum after bile drainage to patients with obstructive jaundice of during the recovery of acute hepatitis than non-esterified bile acids.

Animals↗
PubMed1988

Synthesis of taurine- and/or acetyl group-conjugated poly(D-Glu, D-Lys) derivatives and their effects on fibrinolysis.

A series of C-sulfoethylated and/or N-acetylated poly(D-Glu, D-Lys) (polyGL) derivatives was synthesized and their effects on tissue-type plasminogen activator (t-PA)-induced fibrinolysis were investigated. These derivatives accelerated t-PA-induced plasma (fibrin) clot lysis and t-PA-catalyzed plasminogen activation with the following order of potency: C-sulfoethylated and N-acetylated polyGL greater than N-acetylated polyGL greater than C-sulfoethylated polyGL greater than polyGL. The most potent stimulator C-sulfoethylated and N-acetylated polyGL associated with both t-PA and plasminogen under low ionic conditions, whereas it did not prevent the bindings of t-PA and plasminogen to fibrin. These results suggest that t-PA and plasminogen preferentially bind to sulfated or carboxylated polyanions, which may be required to possess certain neutral groups, and such complex formation may improve the plasminogen activation kinetics in a different manner from that of fibrin.

Acetylation↗
PubMed1988

Implants of quail thymic epithelium generate permanent tolerance in embryonically constructed quail/chick chimeras.

In situ implantation of a quail wing bud into a chick embryo at 4 days of incubation (E4) regularly results in the normal development of the implant followed by its acute rejection starting within two weeks post-hatching. If the epithelial thymic rudiments of the quail donor are implanted into the branchial arch area of the chick recipient after partial removal of its own thymic primordia, a chimeric thymus develops in the chick host and this induces tolerance to the quail wing by the chick recipient. The species identity of cells in chimeric thymuses was mapped using Feulgen-Rossenbeck' staining and immunolabelling with monoclonal antibodies directed against quail or chick B-L antigens. Certain lobes contained only chick cells both at the stromal and hemopoietic cell levels. Others had a quail epithelial stroma containing host hemopoietically derived cells. Only chimeras in which at least one third of the thymic lobes were chimeric showed permanent tolerance to the grafted wing. Since the two species exhibit distinct developmental rates, we decided to study the kinetics of thymic involution after birth. Although the changes in thymus weight and histological structure are fundamentally similar in quail and chick, those in the quail start about 7-8 weeks earlier. In the chimeric thymuses, the lobes whose epithelial cells were quail involuted at the rate of control quail showing no influence of the hemopoietic thymic compartment in this process. Tolerance induced by the thymic epithelium during embryogenesis and in early postnatal life was maintained after a profound involution of the quail thymic graft had occurred.

Animals↗