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Biomedical subjects

K Nagano

Publications and source records attributed to K Nagano.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Progress of the stroke registry system by public health centers, and factors associated with its advancement].

In Japan, a community-based stroke registry was started in 1992 based on the policy of the central government. There are mainly two objectives in this registry system. One is to analyze factors related to the incidence of stroke, and the other is to support home care of stroke patients after leaving the hospital. This system has experienced many difficulties, such as obtaining appropriate information smoothly from the hospitals. Therefore, we investigated all 895 public health centers in Japan through a questionnaire sent by mail, in February 1996. We obtained valid replies from 612 (68%) of the public health centers by March 1996. Results showed that 75% of health centers have established a stroke registry system. Some health centers have promoted the system since 1984. In these systems, the flows of information are mainly of two types: ones which flow to the health centers from the hospitals and the ones which flow to the municipalities. In the former, the number of registered cases were significantly higher and the registry was functioning better than the latter. It has become clear that the health center plays a key role in the successful development of a stroke registry system.

Cerebrovascular Disorders↗
PubMed1998

Cytokine-induced expression of parathyroid hormone-related peptide in cultured human vascular endothelial cells.

Parathyroid hormone-related peptide (PTHrP) is a potent vasodilatory peptide whose expression has been demonstrated in various tissues. The present study was undertaken to examine the regulation of PTHrP expression in cultured endothelial cells derived from human umbilical vein. Immunoradiometric assay revealed that the amount of PTHrP in the conditioned medium was increased by both tumor necrosis factor alpha (TNF-alpha) and interleukin 1beta (IL-1beta) in both a time- and a dose-dependent manner. The induction of PTHrP mRNA was also observed, with a peak after 2 hours of incubation with both TNF-alpha and IL-1beta. Angiotensin II, endothelin-1, and arginine vasopressin had no affect on PTHrP production. Our results suggest that PTHrP produced in vascular endothelial cells in response to cytokines may modulate vascular function as a local factor.

Cells, Cultured↗
PubMed1998

Intracellular distribution of the Wilson's disease gene product (ATPase7B) after in vitro and in vivo exogenous expression in hepatocytes from the LEC rat, an animal model of Wilson's disease.

In patients with Wilson's disease, both copper incorporation into ceruloplasmin and excretion of this metal into bile are impaired. These conditions are caused by a genetic defect in the Wilson's disease gene (ATP7B). To investigate the Wilson's disease gene protein (ATPase7B) in hepatocytes, we constructed an expression plasmid carrying full-length complementary DNA for human Wilson's disease gene and attempted to express the gene in hepatocytes of LEC rats, an animal model of Wilson's disease. Transfection of hepatocytes, either in vitro or in vivo, was done using a newly developed cationic liposome containing 1,4-bis(3-(N-hexadecyl) aminopropyl) piperazine. Immunological analyses of human ATPase7B with specific monoclonal antibodies showed human ATPase7B to be a membrane protein with a molecular mass of 155 kd. Analysis of human ATPase7B expressed in hepatocytes from LEC rats suggested that this protein is present in the trans-Golgi network and at the plasma membrane, a distribution pattern similar to that of Menkes' disease protein (ATPase7A). These findings suggest that these two putative copper-transporting P-type ATPases function similarly at the cellular level. Cotransfection and coexpression of the human Wilson's disease gene and ceruloplasmin gene in cultured hepatocytes indicate that the distribution of ceruloplasmin is always accompanied by ATPase7B at the perinuclear region, but that part of ATPase7B localizes irrespective of the distribution of ceruloplasmin. Based on these investigations, we propose that ATPase7B exists in the trans-Golgi network and transports copper into this compartment. This seems to ensure an appropriate delivery of copper to the apoceruloplasmin. On the other hand, part of ATPase7B that is not accompanied by ceruloplasmin in the perinuclear region and at the plasma membrane seems to contribute to efflux of this metal from the hepatocytes. Thus the distribution patterns of ATPase7B in hepatocytes may explain the dual roles of this P-type ATPase in hepatocytes.

Adenosine Triphosphatases↗
PubMed1998

Orally administered cholera toxin prevents murine intestinal T cells from staphylococcal enterotoxin B-induced anergy.

BACKGROUND & AIMS: Cholera toxin (CT) has been shown to be a strong mucosal adjuvant for the induction of antigen-specific secretory immunoglobulin A (IgA). The mechanism of adjuvant activity of CT is still unknown. The aim of this study was to examine the immunomodulatory function of CT on mucosal T cells using staphylococcal enterotoxin B (SEB) as coadministered oral antigen, because SEB has been shown to directly regulate alpha beta T-cell responses. METHODS: C3H/HeN mice were orally or systemically immunized with SEB and/or CT. The levels of SEB-specific antibodies and frequencies of CD4(+)Vbeta8(+) T cells were analyzed. SEB-specific T-cell proliferation and cytokine production were also determined. RESULTS: Neither SEB-specific IgA nor IgG antibodies were induced in feces when SEB was administered alone. This was a result of the clonal deletion and partial unresponsiveness of CD4(+)Vbeta8(+)T cells in Peyer's patches. On the other hand, SEB-specific antibodies were induced by oral immunization with SEB and CT. Although some degree of clonal deletion was induced by oral immunization with SEB and CT, coadministered CT prevented the induction of anergy for CD4(+)Vbeta8(+) T cells in Peyer's patches. CONCLUSIONS: CT is a powerful immunomodulatory molecule that prevents mucosal T cells from SEB-induced anergy.

Administration, Oral↗
PubMed1998

Role of brain vasopressin in regulation of blood pressure.

Using recent advances in brain physiological, neurohistochemical, and molecular biological techniques, it could be demonstrated that the central action of vasopressin (VP) is important in cardiovascular regulation and in the pathogenesis of hypertension. VP is now known to be located in the area of the brain involved in cardiovascular regulation. Furthermore, in various pathophysiological states, brain VP secretion is regulated separately from the peripheral VP secretion system. The role of brain VP in the regulation of the circadian rhythm of blood pressure is becoming a topic of major interest.

Animals↗
PubMed1998

Microbial contamination of 'sterile water' used in Japanese hospitals.

We examined the following samples of water from 10 hospitals for microbial contamination: water obtained using an ultra filtration system (UF water), a reverse osmosis system (RO water), a water distillation system (distilled water) and tap water. UF water and RO water are used for handwashing before surgery, and distilled water for the preparation of drugs. All 10 samples of tap water examined were contaminated with < 10 colony forming units (cfu)/mL. Thirteen (68%) of 19 samples of UF water, nine (53%) of 17 samples of RO water and 15 (79%) of 19 samples of distilled water were contaminated with 10(1)-10(4) cfu/mL. The majority of micro-organisms were non-fermentative bacteria such as Sphingomonas paucimobilis and CDC gr. IV C-2. Japanese hospitals commonly use UF water and RO water for preoperative handwashing under the assumption that it is sterile. Our results suggest, however, that these types of water are inferior microbiologically to tap water. Distilled water from the dispensary was also contaminated with micro-organisms. The available chlorine content of tap water was 0.17-0.42 ppm and that of UF water (from tap water) 0-0.06 ppm. There was no available chlorine in RO water or distilled water (each from tap water). The reduction or disappearance of available chlorine appears to be associated with microbial contamination of UF water, RO water and distilled water.

Chlorine↗
PubMed1998

Efficacy of ultrasonic mass survey for abdominal cancer.

From August 1983 through March 1995, 204,099 people received ultrasonic mass survey of the abdomen for the first time. Among these examinees, 631 (0.31%) malignant neoplasm cases, such as 201 hepatocellular carcinoma (HCC), 81 gallbladder (GB) cancer, 57 pancreatic cancer, and 169 renal cell carcinoma (RCC), were detected. Three hundred seventy six out of 590 cases (64%), excluding chronic leukemia cases and metastatic liver cancer cases, were surgically resected. The resection rate of HCC, GB cancer, pancreatic cancer, and RCC were 25%, 88%, 49%, and 99%, respectively. The cumulative survival rate of the 376 resected cases was 79.5% at 10 years. The cumulative survival rates of resected cases of HCC, GB cancer, pancreatic cancer and cumulative survival rates of resected cases of HCC, GB cancer, pancreatic cancer and RCC were 34% at ten years, 83% at 10 years, 49% at 7 years, and 99% at 10 years, respectively. Ultrasonic mass survey is dramatically useful for early detection of various kinds of abdominal cancers, especially RCC and GB cancer. From now on, many earlier abdominal cancers will be found by establishing and promoting ultrasonic mass survey systems.

Abdominal Neoplasms↗
PubMed1998

Flow cytometric analysis of cell proliferation kinetics during duodenal ulcer healing.

Cell proliferation in the gastroduodenal mucosa of patients with duodenal ulcers was evaluated using flow cytometry. Forty patients with duodenal ulcers and 12 normal subjects were investigated. Biopsy samples were obtained during endoscopic examination and subjected to DNA analysis by flow cytometry. Thirty patients with duodenal ulcers were healed within 3 months with H2 blockers (tractable or responsive ulcers), whereas 10 patients did not respond to treatment (intractable ulcers). The percentage of cells at the DNA-synthetic phase, an index of cell proliferation, was constant in the adjacent duodenal mucosa 2 cm from ulcer margin and antral mucosa during duodenal ulcer healing. The index at the margin of tractable ulcers was elevated during the active stage (12.9 +/- 1.3), peaked during the healing stage (15.4 +/- 2.8) and returned to the same level at the scarring stage (10.9 +/- 2.0) as normal controls (10.3 +/- 1.7). However, the index was not elevated in intractable ulcers (10.3 +/- 1.7 in the healing stage) and was smaller than in tractable ulcers. These data indicate that augmented mucosal cell proliferation at the ulcer margin plays an important role in duodenal ulcer healing and intractable ulcers are characterized by an abnormal failure to accelerate DNA synthesis to achieve ulcer repair.

Adult↗
PubMed1998

Disturbed pyloric motility in Ws/Ws mutant rats due to deficiency of c-kit-expressing interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) are believed to initiate the basic contractile activity of the gastrointestinal tract. Interstitial cells of Cajal express c-kit receptor tyrosine kinase and are deficient in Ws/Ws mutant rats with a small deletion of the c-kit gene. As Ws/Ws rats show remarkable bile reflux to the stomach, the contraction pressure of the pylorus was compared between Ws/Ws and control +/+ rats. The contraction pressure of the pylorus was measured using a microtransducer, which was inserted through a pin-hole in the anterior wall of the stomach under anesthesia. The magnitude of bile reflux was estimated by measuring the content of bile acids in the stomach. The c-kit messenger RNA-expressing cells were detected by in situ hybridization. Frequency and the maximum pressure of the contraction were comparable between Ws/Ws and +/+ rats, but the duration of the contraction was significantly shorter in Ws/Ws rats than in +/+ rats. The number of c-kit messenger RNA-expressing ICC in the pylorus of Ws/Ws rats was 1.7% that of +/+ rats. The bile reflux observed in Ws/Ws rats was attributed to the decrease in the duration of the pyloric contraction, which appeared to result from the deficiency of c-kit messenger RNA-expressing ICC.

Animal Feed↗
PubMed1998

DNA sequencing of the gene encoding Salmonella typhimurium-derived T-cell inhibitor (STI) and characterization of the gene product, cloned STI.

In a previous study, we found a novel protein which inhibited T-cell responsiveness to interleukin-2 (IL-2) in Salmonella typhimurium and called it S. typhimurium-derived T-cell inhibitor (STI). In this study, we analyzed the DNA sequence of the gene encoding STI. The STI gene was cloned into a plasmid vector, pUC118, and expressed in Escherichia coli JM109. Like native STI, the cloned STI inhibited IL-2-dependent CTLL-2 cell growth. Furthermore, this growth inhibition involved down-regulation of IL-2 receptor expression. These results indicate that the cloned STI expressed in E. coli was identical to native STI. Sequencing revealed that the STI gene contained an open reading frame of 2298 base pairs encoding a precursor form of 765 amino acid residues (molecular mass 83605) that is processed into a mature form of 745 amino acid residues with molecular mass 81 548. Homology analysis revealed that its amino acid sequence was highly homologous with that of the beta-glucosidase of E. coli K-12. We designated the gene encoding STI sti.

Amino Acid Sequence↗
PubMed1998

Cyclooxygenase-2 inhibitors suppress the growth of gastric cancer xenografts via induction of apoptosis in nude mice.

To clarify the role of mitogen-inducible cyclooxygenase (COX-2) in the development of malignant tumors, we investigated the effects of COX-2 inhibitors on the growth of gastric cancer xenografts in nude mice in vivo. MKN45 gastric cancer cells (5 x 10(6) cells/animal) that overexpress COX-2 were inoculated subcutaneously into athymic mice. NS-398, a specific COX-2 inhibitor, or indomethacin, a nonspecific COX-2 inhibitor, was administered orally to animals every day for 20 days. These drugs reduced the tumor volume significantly. Immunohistochemistry using bromodeoxyuridine, nick end labeling, and electron microscopy showed that NS-398 induced apoptosis in cancer cells in a dose-dependent manner and inhibited cancer cell replication slightly. Indomethacin also induced apoptosis and suppressed replication of tumor cells. There was a significant negative correlation between tumor volume and apoptotic cell number within the tumor. These results are consistent with the hypothesis that COX-2 inhibitors suppress growth of gastric cancer xenografts mainly by inducing apoptosis and suppressing replication of the neoplastic cells. It follows that COX-2 plays an important role in the development of gastric cancer.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Mortality in relation to the type of household among elderly people living in a community.

The objective of this study was to determine whether there is an association of mortality with the type of household in elderly people. A cohort of 1,352 elderly people aged 65 years and over at baseline in October 1992 was followed for 42 months. Follow-up was completed for 1,266 (93.6%) (172 deceased and 1,094 alive). From the analysis using the Kaplan-Meier method and the log-rank test, male sex, older age group (75 years and over), no satisfaction with present dwelling, disability, no use of health checks, no practices of daily preventive health promotion, no participation in social activities, and no finding life worth living (no Ikigai) were univariately statistically significantly related to mortality. Furthermore, elderly people living with their spouse only or living alone had higher survival rates than those living with their spouse and children or living with their children, and the curves among the four subclasses of household were significantly different. From the Cox proportional hazards model, living with a spouse only remained as an independent predictor for survival, and living alone was not an increased risk factor for mortality, controlling for sex, age, housing conditions, disability, use of health management, and psychosocial conditions.

Aged↗
PubMed1998

[A case of pharyngeal-cervical-branchial variant of Guillain-Barré syndrome with IgG anti-GT1a antibody].

A 36-year-old man with pharyngeal-cervical-brachial variant of Guillain-Barré syndrome (PCB) was described. Neurologic examination revealed total ophthalmoplegia, pharyngeal-cervical-brachial weakness and hyporeflexia in the upper limbs, sparing power and tendon reflexes in the lower limbs. Enzyme-linked immunosorbent assay showed that he had high titer of IgG antibody to GT1a (1:32,000), which did not cross-react with GQ1 b or GD1a. Thin-layer chromatography immunostaining confirmed that his serum IgG reacted with GT1a. These findings show that IgG anti-GT1a antibody without cross-reactivity with GQ1b plays a role in the development of PCB.

Adult↗
PubMed1997

Transfer RNA docking pair model in the ribosomal pre- and post-translocational states.

A consensus has been reached that the conformation of the anticodon-codon interactions of two adjacent tRNA molecules on the ribosome is a Sundaralingam-type (S-type). Even if it is kept to the S-type, there are still various possibilities. Various experimental data have been supporting an idea that the conformation of A-site tRNA is different from that of P-site tRNA. Those data as well as the recent result of Brimacombe and co-workers that U20:1 of lupin tRNAmMetbound to the A-site was cross-linked to a region, 875-905, of 23S rRNA in combination with the other recent findings of Nierhaus and co-workers about the spin-contrast method of neutron diffraction of the ribosome and the better accessible nucleotide patterns of phosphorothioated tRNAs on the ribosome have led to a new tRNA docking pair model, in which the highly conserved G18 and G19 of D-loop in A-site tRNA and C56 and C61 of TpsiC-loop in P-site tRNA base pair along with the conventional base pairs of adjacent codon-anticodon interactions. This A-P tRNA pair model can be translocated to the P-E tRNA pair model without changing the conformation except the ACCA termini, keeping the position of the growing nascent polypeptide chain.

Base Composition↗
PubMed1997

Identification of arginine vasopressin mRNA in rat aortic smooth muscle cells.

We investigated the expression of mRNA for arginine vasopressin in vascular smooth muscle cells and A10 cells using reverse transcription-polymerase chain reaction and Northern blot analysis. Arginine vasopressin mRNA was identified both in rat aortic smooth muscle cells and A10 cells, suggesting that arginine vasopressin is locally produced in vascular smooth muscle cells. Arginine vasopressin, a potent vasoconstrictor, may modulate vascular function in an autocrine or paracrine fashion.

Animals↗
PubMed1997

Central vasopressin is required for the complete development of deoxycorticosterone-salt hypertension in rats with hereditary diabetes insipidus.

It has been shown that vasopressin receptors are upregulated in the brain and that the central vasopressin pathway is involved in the development of deoxycorticosterone acetate (DOCA)-salt hypertension. However, it is unclear whether central vasopressin, in itself, is essential for this type of hypertension. To clarify this issue, the effect of centrally administered vasopressin on the development of DOCA-salt hypertension was studied in homozygous Brattleboro rats which genetically lack vasopressin. In homozygous Brattleboro rats, treatment with intracerebroventricular infusion of vasopressin (1 ng/h) alone or DOCA-salt (weekly subcutaneous injection of 30 mg/kg deoxycorticosterone acetate and 0.3% NaCl to drink) alone had no effect on systolic blood pressure (SBP). On the other hand, hypertension was partially restored in homozygous Brattleboro rats treated with intracerebroventricular infusion of vasopressin and DOCA-salt (SBP: 175 +/- 4 mmHg), although the magnitude of elevation of SBP was one-third of that in Long Evans rats treated with DOCA-salt (278 +/- 15 mmHg). These hypertensive homozygous Brattleboro rats showed an increase in fluid intake and urinary sodium excretion, as observed in DOCA-salt hypertensive Long Evans rats. These results suggest that central vasopressin is required for the complete development of DOCA-salt hypertension and the mechanism is, in part, due to enhanced sodium intake through the additive effect of central vasopressin and DOCA-salt.

Animals↗