Biomedical subjects

H Oguchi

Publications and source records attributed to H Oguchi.

At least 19 recordsLinked to original sources

PubMed1998

Prospective follow-up study of hepatitis C virus infection in patients undergoing maintenance haemodialysis: comparison among haemodialysis units.

A prospective follow-up study on hepatitis C virus (HCV) infection was conducted in seven haemodialysis units from April 1990 to March 1995. A total of 634 patients were undergoing maintenance haemodialysis in the seven units. Of those, 302 patients participated in the follow-up study; 179 were initially HCV antibody negative and 123 were initially positive. Nine of the 179 initially negative patients became positive for HCV antibody during the follow-up period. In accordance with the appearance of HCV antibody, indicating new infection of HCV, all nine of these patients were diagnosed with HCV viraemia. As no other routes were apparent, HCV infection in all nine patients was likely due to nosocomial transmission. Prevalence of HCV antibody at the start of follow up was significantly higher (P < 0.001) in haemodialysis units A-C (37.9%) than in haemodialysis units D-G (17.0%). Incidence of new HCV infection was significantly higher (P = 0.005) in the former units (2.2% per year) than in the latter (0.2% per year). Ten of the 123 patients who were initially positive for the HCV antibody exhibited a loss of reactivity during the follow-up period; of these 10 patients, nine were negative for HCV-RNA from the start of the study. In conclusion, the incidence of new HCV infection seen in patients undergoing haemodialysis suggests that their risk of acquiring HCV infection is directly related to the prevalence of HCV antibody positive patients being treated in the units.

Adult↗

PubMed1998

Multiple transcripts encoded by the thyroid-specific enhancer-binding protein (T/EBP)/thyroid-specific transcription factor-1 (TTF-1) gene: evidence of autoregulation.

Multiple transcripts derived from the gene encoding rat thyroid-specific enhancer-binding protein (T/EBP)/thyroid-specific transcription factor-1 (TTIF-1) were identified by complementary DNA cloning and sequencing, and Northern blotting analyses. Six different types of complementary DNAs were identified that differ at their 5' noncoding regions; four contain an intron of different lengths, whereas the other two possess no intron. Ribonuclease protection analyses revealed that multiple promoters are scattered throughout the upstream region, and the usage of these different promoters together with alternative splicing leads to a family of T/EBP messenger RNA (mRNA) species. A similar pattern of expression was also found in the human T/EBP gene expressed in a lung carcinoma cell line. Longer T/EBP mRNAs are more abundant in rat FRTL-5 thyroid cells maintained in the absence of TSH (-TSH) than in cells maintained in the presence of TSH (+TSH). Transfection analyses using the rat T/EBP gene DNA upstream of the ATG initiation codon connected to the luciferase reporter plasmid showed a similar relative activity profile between -TSH and +TSH culture conditions, suggesting that the abundance of longer mRNAs in -TSH conditions may not directly correlate with differences in promoter activities. Rather, TSH status might have a role in maintaining the physiological state of the cells. The upstream DNA of the rat and human T/EBP genes share a cluster of high and low sequence similarities, and both possess respectively 24 and 18 putative T/EBP-binding sites throughout. Cotransfection analyses of the T/EBP promoter-reporter constructs with a T/EBP expression vector into human HepG2 cells, which do not express T/EBP, suggested that autoregulation may be involved in controlling both rat and human T/EBP gene expression.

Alternative Splicing↗

PubMed1997

Development of a polymerase chain reaction assay for Mycoplasma salivarium by using the nucleotide sequence within aminopeptidase My gene.

A polymerase chain reaction assay for a 278-nucleotide DNA fragment within aminopeptidase My gene of Mycoplasma salivarium was developed. The assay amplified M. salivarium DNA, but did not amplify DNAs of other mollicutes, bacteria and mammalian cells. The detection limit of the assay was 10 fg of DNA, approximately equivalent to 10 organisms.

Adult↗

PubMed1997

Cerebrospinal fluid interleukin-6 in progressive Neuro-Behçet's syndrome.

Central nervous system (CNS) involvement in Behçet's disease, usually called neuro-Behçet's syndrome (NB), is one of the most serious complications of the disease. The present study examined cerebrospinal fluid (CSF) interleukin-6 (IL-6) activity in patients with NB to explore its relevance to the progressive CNS disease. Paired CSF and serum specimens were obtained from 11 patients who were diagnosed as having progressive NB based on careful clinical observation and from 11 patients with active Behçet's disease but lacking progressive CNS disease. IL-6 levels in the CSF and sera were determined using IL-6-dependent murine hybridoma MH60.BSF2 cells. All 11 patients with progressive NB showed marked elevation of CSF IL-6 activity [0.18-3.90 U/ml, 1.19 +/- 1.18 (mean +/- SD), normal range, <0.010 U/ml]. In contrast, only 5 of the 11 control patients showed very modest CSF IL-6 activity below 0.10 U/ml, and CSF IL-6 was not detected in the other 6 patients. There was no difference in the serum IL-6 activities of patients with progressive NB and control patients. There was no significant correlation of CSF IL-6 activity with serum IL-6 activity, CSF cell counts, CSF total protein levels, or the CSF/serum albumin quotient. These results indicate that persistent chronic CNS inflammation, as evidenced by the enhanced production of IL-6 within the CNS, plays an important role in the pathogenesis of progressive neuropsychiatric manifestations in Behcet's disease.

Adult↗

PubMed1997

Growth hormone-releasing hormone (GRH)-producing pancreatic tumor with no evidence of multiple endocrine neoplasia type 1.

The characteristic features of a 48-year-old male presenting with isolated acromegaly caused by a GRH-producing pancreatic endocrine tumor bearing no relation to MEN1 was reported. The clinical features, laboratory findings, and sellar enlargement were improved after removal of the pancreatic tumor. The resected pancreatic tumor showed positive GRH immunoreactivity and contained abundant GRH mRNA. This tumor is extremely rare and to date only 10 cases have been reported. In the management of acromegaly, the measurement of GRH is recommended and the search for an ectopic source will prevent unnecessary and potentially ineffective pituitary surgery.

Acromegaly↗

PubMed1997

Clinical significance of hepatitis G virus infection in patients on long-term haemodialysis.

Infection with the newly discovered hepatitis G virus (HGV) was analysed in 163 patients on long-term haemodialysis to clarify its prevalence and clinical significance. Hepatitis G virus RNA in serum was measured by polymerase chain reaction with primers corresponding to the putative non-structural 5' region. Of the 163 patients, three (1.8%) were positive for hepatitis B surface antigen, 40 (24.5%) were positive for hepatitis C virus (HCV)-RNA and 16 (9.8%) were positive for HGV-RNA. Five of the 16 patients with HGV-RNA were also positive for HCV-RNA. Patients with HCV and HGV coinfection had undergone a longer duration of haemodialysis (P = 0.001) and had higher units of transfusion (P = 0.031) compared with those without hepatitis virus infection. Transfusion history was significantly higher (P = 0.039) in patients with only HGV infection than in those without hepatitis virus infection. Hepatitis C virus RNA concentration was higher (P = 0.032) in patients with HCV and HGV coinfection than in those with HCV infection only, but alanine aminotransferase (ALT) levels were similar between these two groups. In conclusion, about 10% of patients on haemodialysis were infected with HGV and the infection was closely associated with transfusion history.

Adolescent↗

PubMed1997

The mechanisms of transient hypothyroxinemia in infants born to mothers with Graves' disease.

Transient hypothyroxinemia in infants born to mothers with Graves' disease is a unique disorder first reported by us in 1988. Most mothers of these infants have had no treatment, are diagnosed as having thyrotoxicosis during the last trimester, or were not well controlled during pregnancy. These infants are believed to have transient central hypothyroidism, the mechanisms of which have not been elucidated. We measured TSH-receptor antibody activities in maternal serum and blood thyroxine (T4) (free thyroxine, FT4) and TSH levels in blood dried on filter paper at 1, 3, and 5 d of age in 114 infants born to mothers with Graves' disease. The 114 infants were retrospectively divided into three groups according to the clinical course and thyroid function data: group G, neonatal thyrotoxicosis; group T, transient hypothyroxinemia; and group E, euthyroid. In group T, the dried blood T4 (FT4) level from cord blood and/or 1 d of age blood was 6.0 +/- 2.3 microg/dL (0.92 +/- 0.52 ng/dL), a value significantly higher than that at 5 d of age (3.6 +/- 1.0 microg/dL; 0.38 +/- 0.18 ng/dL) (p = 0.025 in T4, p = 0.042 in FT4). In contrast, these levels were significantly lower at birth relative to 5 d in group G (p = 0.0001 in T4) and not significantly changed in group E. The TSH level of cord blood and/or 1-d-old blood in group T was significantly lower than that of group E (p = 0.0006). Moreover, the TSH levels in response to thyrotropin-releasing hormone were blunted in most infants in group T. Bone maturation was not delayed in group T, compared with euthyroid infants. The higher blood T4 (FT4) levels at birth, relative to 5 d in group T, suggested that the fetal T4 level was higher than that of the newborn period. The fetal T4 level might have been elevated owing to transfer of T4 from mother to fetus during the last trimester when the mother's thyroid function was elevated and consequently the fetal pituitary-thyroid axis was suppressed. Although the serum T4 (FT4) levels were decreased after birth, TSH levels were not elevated, probably because the pituitary-thyroid axis was suppressed. This may be the reason for the transient hypothyroxinemia with a normal TSH level in infants born to mothers with poorly controlled Graves' disease. Weak maternal thyroid-stimulating antibody activities and differences in sensitivity of the thyroid gland to TSH-receptor antibodies may contribute to this unique disorder.

Bone Development↗

PubMed1997

Salivary catecholamine assay for assessing anxiety in pediatric dental patients.

For the behavioral management of pediatric dental patients, it is important to estimate the degree of anxiety during dental treatment. The purpose of this study was to investigate salivary catecholamine levels in children undergoing dental treatment and to assess the degree of anxiety at each dental procedure. The salivary norepinephrine (NE) level was not influenced by a subcutaneous injection of 50 micrograms of NE in 6 adult volunteers, suggesting a poor diffusive effect of plasma NE into the salivary gland. The salivary NE and epinephrine (E) were measured in 8 children between the ages of 3 and 7 years who underwent restorative dental procedures. Salivary NE significantly increased when the children lay on a dental chair and subsequently received infiltration anesthesia. The salivary E level did not show a significant change throughout the study. After the treatment, salivary NE returned to the pretreatment level. These findings suggest that the increase in salivary NE before infiltration anesthesia reflects enhanced peripheral NE release as a result of stress-induced sympathetic responses and that salivary NE assay is useful for the assessment of dental anxiety in children.

Adult↗

PubMed1996

Participation of endodermal epithelial cells on the synthesis of plasma LDL and HDL in the chick yolk sac.

We ultrastructually examined the chick yolk sac endodermal epithelium and evaluated our findings in combination with the biochemical analysis of serum and yolk lipoproteins. Twenty-five to 30 nm-sized particles were demonstrated to be a principal element of the extracellular yolk mass and these were determined to be yolk very low density lipoprotein (VLDL). The particles were shown to be taken up by the epithelial cells via coated pits and engulfed by plasma membrane invaginations together with yolk subdroplets, another element of the yolk mass. Through apical vacuoles, the two yolk elements were incorporated into yolk drops, which were identified to be one of the lysosomal structures by a cytochemical procedure using acid phosphatase (AcP)ase activity. During the last week of incubation, which is the final third of the incubation period, the digestion seemed to progress rapidly in the yolk drops, which came to resemble lipolysosomes; lipoprotein production became active as expressed by an enlarged Golgi apparatus. The newly produced lipoprotein particles were electron-lucent and irregular in size (50-120 nm). They were sequestered in secretory vacuoles and secreted from the vascular surface of the epithelial cells. Finally, the particles were thought to be taken into the vitelline circulation as plasma lipoproteins. The major component of lipoprotein in serum was determined to be low density lipoprotein (LDL) and high density lipoprotein (HDL), while cholesterol content was found to increase during incubation. We concluded that endodermal epithelial cells participate the synthesis of plasma LDL and HDL. For this synthesis the cells probably apply lipids and apo-protein generated from yolk VLDL degradation.

Acid Phosphatase↗

PubMed1996

Comparative study of CA242 and CA19-9 in chronic pancreatitis.

CA242 has been proved to be useful in the diagnosis of pancreatic cancer. The aim of the present study was to clarify the mechanisms contributing to the high specificity of CA242 as compared with CA19-9 resulting from scarce serum elevation of this antigen in patients with chronic pancreatitis by correlating serum levels and endoscopic retrograde choledocho-pancreatography (ERCP) findings and by immunohistochemical analysis. Serum CA19-9 levels were significantly elevated in patients with calcification and with main pancreatic duct (MPD) stenosis or obstruction. On the other hand, serum CA242 levels showed no significant elevation in patients with such factors. Even though such pathological conditions were considered to lead to the stagnation of pancreatic juice, serum CA242 levels seemed to be less affected than serum CA19-9 levels. Immunohistochemical studies of chronic pancreatitis tissues revealed that CA242 was expressed less frequently and less intensely than CA19-9, and the difference in expression was more prominent in the centroacinar cells and terminal ductules. From the results of the present study, it is conceivable that CA242 is less influenced by the stagnation of the pancreatic juice than CA19-9 because of the low levels of expression in ductal systems, which results in the release of this antigen into the circulation in lower amounts than that of CA19-9.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed1996

Inhibitory effect of 220-oxa-1,25-dihydroxyvitamin D3 on the proliferation of pancreatic cancer cell lines.

BACKGROUND & AIMS: Effective chemotherapy for pancreatic cancer is urgently needed. The aim of this study was to compare the anti-proliferative activity of a new vitamin D3 analogue, 22-oxa-1,25-dihydroxyvitamin D3 (22-oxa-calcitriol), on pancreatic cancer cells lines with that of 1,25-dihydroxyvitamin D3 (calcitriol) with analysis of vitamin D receptor status. METHODS: Antiproliferative effects of both agents were compared using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method and by measuring the tumor size of xenograft inoculated into athymic mice. Vitamin D receptor contents by Scatchard analysis and mutational analysis of receptor complementary DNA were performed. RESULTS: In vitro, 22-oxa-calcitriol and calcitriol markedly inhibited the proliferation (3 of 9 cell lines) and caused a G1 phase cell cycle arrest by appearance of numerous domes. In vivo, 22-oxa-calcitriol inhibited the growth of BxPC-3 xenografts more significantly than calcitriol without including hypercalcemia. Hs 766T, showing no response to either agent, had the second highest receptor contents with no abnormalities in its primary structure deduced by receptor complementary DNA. CONCLUSIONS: 22-oxa-calcitriol may provide a more useful tool for the chemotherapy of pancreatic cancer than calcitriol. Also, the susceptibility of the cell lines to both agents is not well determined by evaluating either the contents or the mutation of vitamin D receptor.

Animals↗

PubMed1996

Healing of microvenous polytetrafluoroethylene (PTFE) prostheses implanted into the rat femoral vein by means of 3M precise.

Thirty PTFE prostheses (internal diameter, 1.0 mm; length, 5.0 mm; fibril length, 30 microns) were implanted into rats' femoral veins by means of a coupling device (3M precise microvascular anastomosis system, 3M, St Paul, MN) and evaluated with electron microscopy at regular intervals from 1 day to 3 weeks after implantation to study, in detail, the healing process. Eighty-three percent of mechanically anastomosed grafts were found to be patent. At 1 and 3 days after implantation, the whole length of PTFE was covered with a clot layer containing platelets and a fibrin network. After 1 week, endothelial-like cells originating from the anastomotic sides grew in across the anastomoses. At 3 weeks, the prostheses were completely covered by an endothelial-like cell layer. These results demonstrate that the degree of neo-endothelialization in the microvenous PTFE prosthesis anastomosed with 3M rings was not delayed, as was seen in the healing of microarterial PTFE tubing that was mechanically anastomosed.

Animals↗

PubMed1996

The 3M precise microvascular anastomotic system for implanting PTFE microvenous prostheses into the rat femoral vein.

Successful implantations of PTFE microvenous prostheses with 3M precise anastomosis systems were presented. Twelve PTFE prostheses (Gore-Tex;I.D.1.0 mm) were implanted into rat femoral veins by means of 3M precise technique to evaluated the patency rate. In the control group, PTFE prostheses (n = 12) were implanted by means of end-to-end technique. In the experimental group, patency of the PTFE prostheses was evaluated at 3 (n = 6) and 6 (n = 6) weeks after implantation by means of macroscopic inspection and scanning electron microscopy. All prostheses except one were patent at the time of removal (patency rate 91.7 percent). All the microvenous prostheses were completely covered by an endothelial layer at 3 and 6 weeks after implantation, and no stenosis was observed at the anastomotic sites. In the control group, all prostheses except one were found to be occluded 3 weeks after implantation. These results demonstrate the value of the 3M precise technique when implanting PTFE microvenous prostheses.

Anastomosis, Surgical↗

PubMed1996

A new HLA-DQB10306 allele sharing motifs from DQB103032 and DQB1*04 sequences.

We have discovered a new HLA-DQB1 allele in a Japanese family, MAT. In the family the new allele segregates in three generations and demonstrates the positive association with DRB1*0901. We observed a novel RFLP pattern in the course of examining the modified PCR-RFLP method for HLA-DQB1 genotyping. The PCR-SSOP analysis also showed a new hybridized pattern. Sequence analysis of the allele indicates that it was generated by a gene conversion-like event between the HLADQB1*03032 and one of DQB1*04 contemporary alleles. This new allelic product did not react with all of allosera and monoclonal antibodies against DQ1, DQ2, DQ3, DQ4 and DQ7. The HLA molecule encoded by the allele is not defined by serology. This new allele was officially recognized and named DQB1*0306 by the WHO Nomenclature Committee in November 1995.

Alleles↗

PubMed1996

Defective organification of iodide causing congenital goitrous hypothyroidism.

A 26-yr-old Japanese woman with congenital goitrous hypo-thyroidism and sensorineural deafness underwent a thyroidectomy. Examination of the thyroid gland revealed characteristic features of multinodular goiter. The T3 and T4 content in thyroglobulin (Tg) were 0.03 and 0.02 mol/mol Tg, respectively. Iodide incorporation into Tg, using slices of the thyroid tissue, revealed that iodide organification of thyroid tissue from our patient was markedly lower than that of normal controls. Then, guaiacol and iodide oxidation activities of thyroid peroxidase (TPO) in our patient's thyroid tissue were lower than those of normal controls (guaiacol assay: 1.92 vs. 30.0 +/- 5.7 mGU/mg protein; iodide assay: 1.1 vs. 6.6 +/- 2.8 mIU/mg protein). Lineweaver-Burk plot analysis of the oxidation rates of guaiacol and iodide indicated that this patient's TPO had a defect in the binding of guaiacol and iodide, but the coupling activity of the patient's TPO was not decreased compared with those of two normal thyroids. In this case and in control subjects, Nothern gel analysis of TPO messenger RNA from unstimulated and TSH-stimulated thyroid cells revealed a 3.2 kilobase species in the former and four distinct messenger RNA species of 4.0, 3.2, 2.1, and 1.7 kilobases in the latter. Western blot analysis of TPOs obtained from this patient and from control subjects identified the same 107 kDa protein, using antimicrosomal antibody-positive serum. We analyzed the coding sequence in the patient's TPO gene by using polymerase chain reaction technique. A single point mutation of G-->C at 1265 base pair was detected only in the TPO gene, but this point mutation does not alter the amino acid residue. It is possible that posttranslational modification such as abnormal glycosylation may occur in the TPO molecules. Furthermore, it is possible that there are differences in the tertiary structures of the TPO molecules between our patient and normal subjects. The above abnormalities of TPO molecules may play an important role in our patient's dyshormonogenesis.

Adult↗

PubMed1996

Gallium alloy restorations in primary teeth: a 12-month study.

The authors placed 60 Class I and Class V restorations in the primary molars of children aged 4 to 10 years using a gallium alloy. Within one year after placement, the surfaces of all the restorations had deteriorated significantly due to corrosion, and the authors found remarkable amounts of corrosion products on restorations retrieved after tooth extraction or loss. The marginal integrity of many of the Class I restorations deteriorated slightly during the study; the Class V restorations showed no marginal breakdown. No other problems were detected after one year. These data indicate that the gallium alloy tested had insufficient resistance to corrosion to serve as a permanent restorative material. However, the authors suggest consideration of this alloy for use in primary teeth to reduce the exposure of children and dental professionals to mercury-containing amalgam.

Alloys↗

PubMed1995

The complete nucleotide sequence of the mouse thyroid-specific enhancer-binding protein (T/EBP) gene: extensive identity of the deduced amino acid sequence with the human protein.

A mouse thyroid-specific enhancer-binding protein (T/EBP) gene and its flanking regions have been cloned and completely sequenced. The gene consists of 2 exons and exhibits high similarity (83-97%) to the rat sequence throughout the coding region and including an intron and up to 1.3 kbp upstream to the ATG initiation codon. A cDNA clone encoding human T/EBP has been also isolated and sequenced. Comparison of the deduced amino acid sequence of T/EBP revealed an extensive identity of 98% between mouse and the human protein.

Amino Acid Sequence↗

PubMed1995

Long-term histological evaluation of hydroxyapatite ceramics in humans.

We have investigated the interface between bone and hydroxyapatite (HA) chronically implanted in man. By light microscopy, HA appeared to bind directly to bone without intervening fibrous tissue. By transmission electron microscopy, two patterns were noted: (1) HA either bound directly to bone; or (2) electron-dense material intervened between HA and bone. The orientation of bone collagen fibres likewise showed two patterns: (1) collagen fibres were oriented parallel to the HA; or (2) the fibres were aligned perpendicularly. We have observed similar binding properties of HA to the jaw bone of humans in vivo and in vitro.

Adult↗