Biomedical subjects

K Yasui

Publications and source records attributed to K Yasui.

At least 181 records · Page 10Linked to original sources

PubMed1996

Effects of high-dose granulocyte colony-stimulating factor on neutrophil functions.

We evaluated the effects of high-dose recombinant human granulocyte colony-stimulating factor (rhG-CSF) therapy on N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced chemotaxis and superoxide (O2-) production in neutrophils from four patients with aplastic anaemia. The FMLP-induced chemotaxis and O2- production in the neutrophils of all four patients were normal before the rhG-CSF treatment. After the administration of high-dose rhG-CSF, chemotaxis in agarose was decreased, adherence and O2- production were enhanced in all the patients. An excessive increase of neutrophils with augmented adhesiveness and oxygen radical production may be harmful. Care should be taken in regard to neutrophil toxicity when high-dose G-CSF is used clinically.

Adolescent↗

PubMed1996

Molecular assembly of RNA polymerase II from the fission yeast Schizosaccharomyces pombe: subunit-subunit contact network involving Rpb5.

BACKGROUND: Eukaryotic RNA polymerase II is composed of more than 10 polypeptide chains. The minimum and essential subunits for RNA synthesis have not yet been identified. Toward this ultimate goal, we analysed the topological arrangement of the putative subunits. Here we report a subunit-subunit contact network involving subunit 5 of the fission yeast Schizosaccharomyces pombe RNA polymerase II. RESULTS: The rpb5+ gene encoding subunit 5 of RNA polymerase II was cloned from the fission yeast Schizosaccharomyces pombe. The polypeptide predicted from DNA sequence of the rpb5+ gene consists of 210 amino acids with a calculated molecular weight of 23914. The homology of the amino acid sequence is 55% and 43% with Saccharomyces cerevisiae RPB5 and human hRPB25, respectively. Far-Western blot analysis of S. pombe RNA polymerase II using 32P-labelled recombinant Rpb5 fused to glutathione S-transferase (GST) as a probe, indicated that Rpb5 binds strongly to membrane-immobilized Rpb1, Rpb2 and Rpb3 and weakly to Rpb5 and a 15-kDa subunit (Rpb8 or Rpb11). In agreement with this result, the 32P-labelled Rpb3 probe showed a strong binding signal against Rpb5 in addition to Rpb1 and Rpb2. The existence of Rpb5-Rpb3 contact was supported by detection of complexes formed between these two proteins synthesized in vitro using protein-immobilized beads. CONCLUSION: Rpb3 and Rpb5, the putative subunits of RNA polymerase II, associate each other to form binary complexes. These two subunits also bind to the two large subunits, Rpb1 and Rpb2, independently.

Amino Acid Sequence↗

PubMed1996

Atrial natriuretic peptide accelerates proliferation of chick embryonic cardiomyocytes in vitro.

The developing embryonic heart has been reported to contain significant levels of atrial natriuretic peptide (ANP). In this study, the role of ANP in cardiac development was evaluated using cultured cardiomyocytes isolated from chick embryos. We analyzed the effect of ANP on cell number, DNA synthesis, total RNA level, the expression of cell-cycle-specific and sarcomeric proteins, and levels of lactate dehydrogenase and creatine phosphokinase. ANP increased overall DNA synthesis (measured by BrdU incorporation, P < 0.01) and enhanced cell proliferation. Morphologically, the development of the cardiomyocyte network was distinctly enhanced in the ANP-treated cells. Cellular RNA content was elevated; likewise, myosin and tropomyosin biosynthesis was significantly greater in ANP-treated cells. In addition, expression of G1/S-specific protein increased, whereas G2/M-specific protein remained unchanged by ANP treatment. An antibody against ANP and a specific ANP receptor antagonist, HS-142-1, antagonized and/or attenuated the action of ANP on both cell proliferation and protein biosynthesis. These results indicate that ANP accelerates myocardial cell proliferation by enhancing entry into S phase and by increasing DNA synthesis during S phase specifically through receptor mediated pathway. The in vitro effects of ANP on myocardial cell proliferation, together with the elevated levels of ANP seen in vivo during normal heart formation, suggest a possible autocrine function of ANP in embryonic cardiac development.

Animals↗

PubMed1996

Cultivation of hepatitis C virus in primary hepatocyte culture from patients with chronic hepatitis C results in release of high titre infectious virus.

To investigate the viral replication cycle and genomic heterogeneity of hepatitis C virus (HCV), we established an HCV cultivation system by using a primary hepatocyte culture from patients with chronic hepatitis C. Liver tissue was obtained by needle biopsy or surgery, then hepatocytes were isolated by collagenase digestion. After several weeks, we determined the HCV RNA titre of the cultured cells and supernatant by a competitive polymerase chain reaction (PCR) method. A significant amount of HCV RNA was observed in the cells and supernatant during cultivation. Negative-strand RNA, regarded as a marker of viral replication, could be detected by a strand-specific reverse transcription PCR method and the HCV core protein could be detected by immunofluorescence microscopy. Many HCV particles released into the supernatant were infectious. In addition, we compared the nucleotide sequences in the E2/NS1 region of pre- and post-cultivation hepatocytes for 8 weeks. At the beginning of the culture period, three major HCV types containing two subtypes were isolated. Following cultivation, the same types were isolated from the cultured hepatocytes in the same ratio as prior to cultivation. We could detect the same clones in this patient's serum, but in vivo we observed genetic variability over a 6 month interval. One clone detected throughout the 6 month period mutated extensively in the hypervariable region. These results indicated that HCV can replicate in cultured hepatocytes, and that infectious virions are released into the supernatant. This cultivation system should facilitate the study of HCV genomic heterogeneity, infection and replication.

Adult↗

PubMed1996

Assessment of clinical significance of positive blood cultures of relatively low-virulence isolates.

In Omori Hospital, Toho University School of Medicine, relatively low-virulence blood isolates, including coagulase-negative staphylococci (CNS), enterococci and nonfermentative gram-negative rods other than Pseudomonas aeruginosa comprised c. 60% of total blood isolates. A retrospective study was conducted to assess their clinical significance by reviewing a total of 91 hospital charts. The physicians' assessments of these positive blood cultures as recorded in the charts were classified into four categories--sepsis, possible sepsis, contamination and no comment. The episodes classified as sepsis accounted for 5.0-19.6%. These episodes were also evaluated by a graded clinical significance score based on multiple factors, including number of positive cultures and clinical signs. The scores for the 91 episodes covered a wide range from 1 to 9, indicating that both contaminants and causative organisms may have been involved. The episodes judged as sepsis or possible sepsis tended to have higher scores. The scores for the episodes associated with enterococci were also higher than those involving CNS or non-fermentative gram-negative rods. The scores for episodes associated with intravenous hyperalimentation catheters were higher than those not associated with the catheters.

Bacteremia↗

PubMed1996

Differential effects of angiostatic steroids and dexamethasone on angiogenesis and cytokine levels in rat sponge implants.

1. Subcutaneous implantation of sterile polyether sponges elicited a reproducible neovascular response in rats, as determined by blood flow measurement with a 133Xe clearance technique and confirmed histologically. This model was used to monitor the levels of two cytokines during angiogenesis and to compare the activities of angiostatic steroids and anti-inflammatory steroids. 2. Initial experiments followed the neovascular development over a 20-day period. Daily local injection of hydrocortisone caused a dose-dependent (0.5, 5 and 50 micrograms per sponge) inhibition of the basal sponge-induced angiogenesis. However, daily systemic treatment of hydrocortisone (2, 10 and 50 mg kg-1, s.c.) was less effective at inhibiting angiogenesis, and this inhibition was not sustained by day 20 after sponge implantation. 3. To investigate the involvement of cytokines during the course of angiogenesis, we measured the endogenous levels of tumour necrosis factor-alpha (TNF-alpha) and interleukin 6 (IL-6) in sponge implants. Levels of IL-6 and TNF-alpha peaked at day 7 and day 11 after implantation, respectively. These cytokine levels subsided through the completion of angiogenesis by day 20. 4. Subsequent experiments were carried out over a 14-day period. Among the three angiostatic steroids tested, U-24067 (6 alpha-fluoro-17,21 - dihydroxy-16 alpha-methylpregna -4,9(11)-diene-3,20-dione-21-acetate) showed a dose-dependent inhibition (0.5, 5 and 50 micrograms per sponge per day) of sponge-induced angiogenesis. Tetrahydro-S was also effective at 5 micrograms doses, but medroxyprogesterone failed to affect the angiogenic response. None of these steroids caused atrophies of the spleen and thymus. 5. Daily local injection of dexamethasone (0.5 microgram per sponge) inhibited the basal sponge-induced angiogenesis almost completely. Although higher doses of dexamethasone (5 and 50 micrograms per sponge) did not produce further inhibition of angiogenesis, they caused severe spleen and thymus weight losses, indicative of immunosuppression. 6. At the daily dose of 5 micrograms per sponge, dexamethasone inhibited angiogenesis and produced a marked reduction in the levels of TNF-alpha and IL-6 at day 14. In contrast, hydrocortisone, U-24067 and tetrahydro-S did not influence the levels of TNF-alpha and IL-6. 7. We concluded that the anti-angiogenic activity of angiostatic steroids and anti-inflammatory steroids in the rat sponge model is independent of their ability to reduce the production of TNF-alpha and IL-6. The differential effects of angiostatic and anti-inflammatory steroids suggest that U-24067 and its derivatives may have therapeutic potential in the management of angiogenic diseases such as rheumatoid arthritis.

Animals↗

PubMed1996

Circulating HCV-RNA, HCV genotype, and liver histology in asymptomatic individuals reactive for anti-HCV antibody and their follow-up study.

The present study was aimed to clarify the virologic status, liver histologies, and the results of follow-up liver tests in symptom-free individuals with anti-HCV antibodies and normal liver tests. Forty-nine individuals with normal liver tests and positive second generation anti-HCV antibody assay were entered into this study. Cases with hepatitis C viremia were evaluated for HCV genotype, amount of circulating HCV-RNA, and liver histology and were followed-up for more than one year. Of the forty-nine individuals, 36 had hepatitis C viremia, indicated by polymerase chain reaction (PCR) assay. Liver histology was as follows: 3 had non-specific changes, 25 had chronic persistent hepatitis (CPH), and 8 had chronic active hepatitis (CAH). Twenty-four cases with CPH and CAH developed an elevated AST and/or ALT concentration (> 30 IU/l) between 12 and 32 months of follow-up. The amount of circulating HCV-RNA ranged from 10(2) to 10(7) copies/50 microliters serum. The distribution of HCV genotypes was nearly the same as that for symptomatic CAH. These data suggest that the histological examination and follow-up examination are very important for following symptom-free individuals with hepatitis C viremia because there are some candidates for interferon therapy among them. There are few individuals who will remain healthy among asymptomatic HCV carriers.

Adult↗

PubMed1996

Demonstration of borna disease virus RNA in peripheral blood mononuclear cells derived from domestic cats in Japan.

Borna disease virus (BDV) naturally infects horses, sheep, and several other species, including humans, and it is believed to be related to neurological disorders. BDV infection in domestic cats has also been demonstrated by serological assays. We demonstrated for the first time BDV RNA in peripheral blood mononuclear cells from 11 of 83 (13.3%) randomly selected domestic cats in Japan by nested reverse transcriptase-PCR. The BDVs from cats were similar to but slightly different from those from horses and humans, as shown by sequencing the reverse transcriptase-PCR products. None of the cats was positive for both BDV RNA and anti-BDV antibodies.

Amino Acid Sequence↗

PubMed1996

Sphingolipid actions on sodium and calcium currents of rat ventricular myocytes.

Sphingosine, an endogenous phospholipid known to produce significant decreases in myoplasmic Ca2+ transients, was shown to have a pronounced inhibitory effect on inward Na+ and L-type Ca2+ currents in rat ventricular myocytes. Sphingosine action was accompanied by a slowing of inactivation of both kinds of current. Both sphingosine and sphingosylphosphorylcholine (SPC) caused depolarizing shifts in the activation curves for the two channels. In tests on Ca2+ currents, sphingosine neither showed high affinity for inactivated states nor exhibited any use dependence. The mechanism of the blocking action of sphingosine does not appear to involve effects on bulk surface charge or, at least for Ca2+ channels, a voltage-dependent block. Instead, the results appear most consistent with an effect of sphingosine on channel gating. The shift in the voltage dependence of channel activation by sphingosine and SPC appears likely to be a feature of both the hydrocarbon chains and the net positive charge of these amphiphiles.

Animals↗

PubMed1996

Release profiles of recombinant human tumor necrosis factor from Ca(2+)-triggering liposome in vivo.

After the administration of the recombinant human tumor necrosis factor (rHuTNF), plasma concentration could be controlled from egg yolk phosphatidylcholine (eggPC)-egg yolk phosphatidic acid (eggPA) liposome (EggPA liposome). The plasma concentration was highest after the rHuTNF solution administration. Although the concentration after the 30% EggPA liposome administration was much lower than that after the solution administration, the antitumor effect against Meth A sarcoma was equal to that of the rHuTNF solution. Non-linear elimination of rHuTNF in rat could explain these phenomena. First, to evaluate the intact absorption profile, we developed a non-linear absorption calculating program (NLAP). The calculation revealed little difference in the total absorption amounts between the solution and liposomes. The absorption rate from the liposomes was lower than that from the solution, and finally, the control of rHuTNF release from liposomes was also confirmed in vivo. These findings suggested that the sustained release of rHuTNF from liposomes maintained high drug concentration in the injected site and decreased the systemic drug concentration.

Animals↗

PubMed1996

Differential effect of benexate hydrochloride betadex on prostaglandin levels in stomach and inflammatory site in rats.

We compared the effects of an anti-ulcer agent, benexate hydrochloride betadex (BHB), on prostaglandin (PG) levels in gastric tissue and inflammatory exudate in untreated and indomethacin-treated rats. BHB (100, 300 and 1000 mg/kg, p.o.) showed dose-dependent inhibition of gastric mucosal lesions induced by indomethacin (30 mg/kg, p.o.). Sustained decrease of PGs (PGE2 and 6-keto-PGF(1alpha)) in the gastric wall was observed from 0.5 to 6 hr after indomethacin treatment. BHB (300 and 1000 mg/kg) dose-dependently led to recovery of the indomethacin-induced decrease of gastric PGs at 1 and 6 hr after dosing. It did not antagonize the indomethacin-induced decrease of PG levels in the pleural exudate of carrageenin pleurisy nor did it affect the anti-inflammatory effects of indomethacin. BHB (100 to 1000 mg/kg) alone increased gastric PGE2 by 61% to 113%, while it decreased PGE2 levels in the pleural exudate by 9% to 71% at 6 hr after dosing. These results suggest that sustained increase of gastric PGE2 by BHB could be responsible for protection against indomethacin-induced gastric mucosal lesions and that BHB is a suitable anti-ulcer agent for NSAIDs without compromising their anti-inflammatory effects.

6-Ketoprostaglandin F1 alpha↗

PubMed1996

Postoperative staging of gastric carcinoma. A comparison between the UICC stage classification and the 12th edition of the Japanese General Rules for Gastric Cancer Study.

BACKGROUND: The feasibility of the latest edition of the Japanese General Rules for Gastric Cancer Study (GRGCS) is evaluated by comparison with the TNM system. METHODS: In a 5-year period from 1985 to 1989, 978 patients with gastric cancer underwent laparotomies at the Dept. of Gastroenterological Surgery, Aichi Centre Centre, Japan. All the patients have now been followed up for 5 years or until death. These patients were retrospectively classified into appropriate clinical stages and residual tumour status on the basis of the GRGCS and the 4th edition of the TNM classification by the UICC, and survival curves for various stages and subgroups were evaluated. RESULTS: The GRGCS classification provided useful information by splitting UICC stage IV into stages IVa and IVb, and R0 into curabilities A and B, both subgroups showing significant differences in the survival curves. CONCLUSIONS: The new edition of the GRGCS can be recommended as a useful staging manual for gastric cancer.

Follow-Up Studies↗

PubMed1996

Chemical modification of PA-48153C, a novel immunosuppressant isolated from Streptomyces prunicolor PA-48153.

5beta-Methoxy (20), 14-methyl (24), 14,14-dibromo-15-nor (25), 8-O-acyl (26-45), 8-O-alkyl (46), 8-O-alkoxycarbonyl (47, 48), and 8-O-carbamoyl (49) derivatives of PA-48153C, a novel immunosuppressant isolated from fermentation products of Streptomyces prunicolor PA-48153, were prepared. These compounds were found to retain the inhibitory activity on the responses of both T and B cells to mitogens. Among them, the C-8 hexanoate 28 showed potent suppressive effects on mitogen responses with less cytotoxicity to EL4 cells and was selected for in vivo evaluation.

Animals↗

PubMed1996

Gastric remnant carcinoma after partial gastrectomy for benign and malignant gastric lesions.

BACKGROUND: A retrospective study was designed to evaluate the clinicopathologic characteristics and prognosis of gastric stump carcinoma (GSC) after gastrectomy for gastric adenocarcinoma. STUDY DESIGN: A comparison of the clinicopathologic features was made between 12 cases of GSC and 27 cases of remnant carcinoma (RC) following gastrectomy for adenocarcinoma. The various factors influencing survival of both groups of patients were evaluated separately and by multivariate analysis. RESULTS: Gastric stump carcinoma emerges late after initial gastrectomy and has a significant tendency toward lymph node metastasis. No difference was observed between the survival curves for patients with GSC or RC after gastrectomy for malignancy. Serosal invasion was the factor most affecting survival. CONCLUSIONS: Early diagnosis is most important for management of the disease, and only patients with T2 staged GSC according to the Union Internationale Contre le Cancer classification system might benefit from extensive lymphadenectomies.

Adenocarcinoma↗

PubMed1996

The prognostic value of preoperative serum levels of CEA and CA19-9 in patients with gastric cancer.

OBJECTIVES: The clinical significance of preoperative serum levels of tumor markers CEA and CA19-9 was evaluated in gastric cancer patients. METHODS: Serum levels of CEA and CA19-9 were measured in 663 patients with gastric cancer who underwent laparotomies over a recent 4-yr period (1990-1993). The correlations between the serum levels of tumor markers and several clinicopathological factors were evaluated by univariate analysis. The significance of the tumor markers as prognostic factors was assessed by multivariate analysis. RESULTS: The positivity rates of CEA and CA19-9 were 16.6% and 16.0%, respectively. The positivity of CEA correlated well with the sex of the patients, hepatic, peritoneal, and nodal metastases and the depths of tumors, but it correlated weakly with a tumor's histological type. The positivity of CA19-9 correlated well with various forms of metastases, depths, and tumor size. A significant in prognosis was observed between patients positive and negative for CA19-9 among those undergoing R0 resection. Multivariate analysis also revealed that serum CA19-9 was better than CEA as a prognostic factor. CONCLUSIONS: CA19-9 in the preoperative sera is a good prognostic factor in gastric cancer patients, although tumor markers continue to have only limited diagnostic usefulness.

Biomarkers, Tumor↗

PubMed1996

[Successful combination chemotherapy including deoxycoformycin in a case of cutaneous T cell lymphoma].

A 44-year-old woman was admitted to our department because of fever and skin eruptions on August, 1991. Physical examination revealed superficial lymph node swelling, hepatosplenomegaly and generalized erythroderma. Laboratory findings were as follows; WBC 21,490/microliters with 67% lymphocytes including flower cells. The surface phenotype of lymphocytes was positive for CD2, CD4, CD25, CD29 suggesting helper-inducer T cell. Skin and lymph node biopsies revealed the infiltration of T cells with indented nuclei. Anti-HTLV-1 antibodies in the serum and HTLV-1 proviral DNA analysis by PCR method were negative. She was diagnosed as CTCL, and she was treated with prednisolone. However, her erythroderma deteriorated gradually, in spite of well-controlled lymphocyte counts. Combination chemotherapy, utilizing vincristine, etoposide and cyclophosphamide, was effective against organomegaly but not against generalized erythroderma. After DCF was initiated at a weekly dose of 7.5 mg, her erythroderma improved rapidly and markedly with the disappearance of severe itching, and she achieved complete remission. Our results suggest that DCF is beneficial for chemotherapy-resistant generalized erythroderma in CTCL.

Adult↗

PubMed1996

Visualization of routes of lymphatic drainage of the gallbladder with a carbon particle suspension.

BACKGROUND: Although carcinoma of the gallbladder frequently spreads lymphatically, few reports exist about the evaluation of routes of lymphatic drainage of the gallbladder by vital staining. The purpose of this study was to visualize drainage routes and the extent of lymphatic flow from the gallbladder by using vital staining with a carbon particle suspension (CH40). STUDY DESIGN: In 20 patients, 0.3 to 0.5 mL of carbon particle suspension was injected into first station nodes for the gallbladder, the cystic node or pericholedochal node, intraoperatively. After a Kocher maneuver was performed, lymph nodes and lymphatic vessels blackened by the stain were visualized macroscopically. RESULTS: Lymphatic pathways from the gallbladder were classified into three routes: right, left, and hilar. The right route, which ran along the common bile duct to the superior retropancreaticoduodenal node or the retroportal node and reached the para-aortic nodes, was stained in 95 percent of patients. The left route, which traveled toward lymph nodes medial to the hepatoduodenal ligament through the posterior aspect of the head of the pancreas, was stained in less than 50 percent of patients. Among lymph nodes along the left route, the posterior common hepatic node was most frequently stained (45 percent). The hilar route, which ascended toward the hepatic hilus, was stained in 20 percent of patients. CONCLUSIONS: These data demonstrate that the right route is a main pathway of lymphatic drainage from the gallbladder, while the left and hilar routes are branch lines. The para-aortic nodes, regarded as final regional nodes for the gallbladder, should be removed during radical surgery for advanced carcinoma of the gallbladder. Drainage along the hilar route may cause metastasis to the liver.

Carbon↗

PubMed1996

Smooth pursuit eye movements elicited by pseudorandom target motion in normal subjects.

The purpose of this study was to determine which test conditions are appropriate for clinical examination of predictive control ability in smooth pursuit eye movements (SPEM). A combination of sinusoidal and pseudorandom target motion was employed to examine SPEM. Pseudorandom waves were generated by summing sinusoidal components spaced at 0.05 Hz intervals over three frequency ranges: 0.05 to 0.5 Hz, 0.05 to 1 Hz and 0.05 to 1.5 Hz. The peak amplitude of the resultant target waveform was set at 30 degrees. Testing was performed with 8 normal subjects. The results indicate a SPEM gain of 0.9 for 0.05-0.5 Hz, 0.7 for 0.05-1 Hz and 0.3 for 0.05-1.5 Hz. It is concluded that the pseudorandom wave of 0.05 to 1 Hz in frequency range is most suitable for clinical use.

Adult↗