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Biomedical subjects

T Harada

Publications and source records attributed to T Harada.

At least 433 records · Page 24Linked to original sources
PubMed1995

Protection of cultured rat gastric cells against oxidant stress by iron chelation. Role of lipid peroxidation.

Reactive oxygen metabolites may be involved in the pathogenesis of ethanol-, nonsteroidal antiinflammatory drug-, Helicobacter pylori-, or ischemia/reoxygenation-induced gastric mucosal injury in vivo. Iron plays a critical role in mediating oxidant injury in vitro. The present study examined a possible role of lipid peroxidation in inducing oxidant damage by determining the effect of iron chelation on cytotoxicity and on lipid peroxidation in cultured rat gastric cells. Cytotoxicity was quantified by 51Cr release from prelabeled cells that were exposed to tert-butyl hydroperoxide (tBHP) so as to overwhelm the glutathione redox cycle. Lipid peroxidation was assessed by measuring malondialdehyde (MDA) production. tBHP caused a time-related and dose-dependent increase of 51Cr release. The presence of phenanthroline (a chelator of Fe2+) during tBHP exposure and pretreatment with deferoxamine (a chelator of Fe3+) reduced tBHP-induced 51Cr release dose dependently. The generation of MDA increased as the concentrations of tBHP increased, but in a time course study, such generation preceded cytolysis. Both iron chelators attenuated MDA production in a dose-dependent fashion. Oxidant stress causes lipid peroxidation in cultured gastric cells, which is then followed by cytolysis. Iron plays a critical role in inducing lipid peroxidation as well as in mediating cytolysis. Iron chelation protects these cells from oxidant stress presumably through inhibition of lipid peroxidation.

Animals↗
PubMed1995

A retrospective study of hepatitis C virus carriers in a local endemic town in Japan. A possible presence of asymptomatic carrier.

Chronic hepatitis, cirrhosis, and hepatocellular carcinoma are the accepted sequelae of chronic hepatitis C virus (HCV) infection. However, the real natural history of HCV infection is not still well understood. To approach this problem, we investigated 91 individuals positive for antibodies against HCV (anti-HCV), who have received annual liver function examination in a local town known to have had high carrier rates of hepatitis B virus (HBV) and HCV. Among the 91 anti-HCV-positive individuals, 63 had undertaken the annual examination more than five times in the past 14 years. We analyzed retrospectively the past liver function test results of these 63 subjects and evaluated their present virological status by determining HCV genotypes and estimating quantity of HCV RNA in the sera. Among the 63 subjects, 50 (79.4%) had HCV RNA in the serum and 40 (80%) of the 50 subjects with HCV RNA had abnormal alanine aminotransferase or aspartate aminotransferase level more than once in their records. However, the other 10 (20%) had no abnormal levels during the period examined. Six of 50 (12%) had ultrasonographic findings suggestive of cirrhosis. Thus, HCV-infected individuals in this area did not seem to have progressive liver diseases. Considering the advanced ages of the individuals examined (mean 64 years old), we may have observed a stage in the natural history of HCV infection in which viremia persists in most individuals and the tendency to progress to serious chronic liver disease is mild.

Base Sequence↗
PubMed1995

Spatial distribution and pattern of extrinsic nerve strands in the aganglionic segment of congenital aganglionosis: stereoscopic analysis in spotting lethal rats.

The distribution and pathways of extrinsic enteric nerves in the aganglionic segment in Hirschsprung's disease have not completely delineated. The zinc iodide-osmic acid method was used to investigate nerve fibers of the intestine in aganglionic rats. A light microscope equipped with a polarizing filter system clarified the major pathways and the fine distribution of extrinsic nerves in the aganglionic segment of a long-segment aganglionic rat model. Two sets of extrinsic nerve strands were observed in the distal aganglionic colon; one consisted of a continuous hypertrophied network located between the longitudinal and circular muscle coats, and the other involved branches that coursed along the blood vessels in the submucosal layer and that originated in the nearby mesentery. These two sets of nerve strands were connected by fine nerve fibers. Hypertrophied myenteric nerve strands were also present in normal (ganglionic) colon, fewer strands were found in the proximal aganglionic colon, and none were found in the ileum. The authors speculate that the ascending extrinsic nerve strands disappear from the ileum in cases of long-segment colonic aganglionosis, by the same mechanism that occurs in normally innervated bowel.

Animals↗
PubMed1995

Expression of ret proto-oncogene products in the hypoganglionic segment of the small intestine of congenital aganglionosis rats.

The ret proto-oncogene (proto-ret) encodes a receptor tyrosine kinase that contains a cadherin-related sequence in the extracellular domain, which plays an important role in control of normal cell growth and differentiation. Recent studies have shown that familial Hirschsprung's disease is closely linked to the proto-ret locus. Immunohistologically studies on congenital aganglionosis rats were made using polyclonal antibody generated for the carboxy-terminal sequence of the proto-ret products. Immunoreactivity was investigated in the small and large intestines of mutant and control rats. It was increased in the ganglia of the hypoganglionic segment of the small intestine and was minimal in the normoganglionic small intestinal segment of congenital aganglionosis in rats. The reactivity was also strong in the ganglia of the large intestine of normal rats. Because the proto-ret is preferentially expressed in the neuronal tissue and plays a critical role in differentiation of apparently multipotential neural crest cells to enteric neurons, the results suggest that abnormal development of local vagal neural crest cells, which were influenced by spatially regulating factors, results in the hypoganglionic segment.

Animals↗
PubMed1995

Ultrasound-guided microwave thermotherapy on a VX-2 carcinoma implanted in rabbit kidney.

A temperature greater than 60 degrees C was maintained for 60 s within a 5-mm radius of a microwave electrode implanted in a rabbit kidney using 2450 MHz at 100 W for 30 s. Histological examination revealed complete coagulation necrosis in that area. VX-2 cells were inoculated into the kidneys of 10 rabbits. One week later, five rabbits received ultrasound-guided microwave thermotherapy, and the remaining five rabbits received no treatment. All rabbits with microwave thermotherapy had a complete response to treatment while all rabbits without therapy died of cancer within 6 weeks of the VX-2 implantation. These results indicate that ultrasound-guided microwave thermotherapy has the potential of being a nephron-salvaging treatment for small renal tumors.

Animals↗
PubMed1995

Synthesis of type III collagen and type IV collagen by tubular epithelial cells in diabetic nephropathy.

Overproduction of extracellular matrix (ECM) is considered to be primarily responsible for both glomerular and tubulointerstitial (TI) changes in diabetic nephropathy (DN). To clarify the possible role of the collagens in TI damage in DN, type III interstitial collagen and type IV basement membrane collagen were studied in 10 cases of DN and 10 control cases by immunohistochemistry and in situ hybridization techniques. In control cases, no immunostaining for type III collagen was found in the renal tubules, while strongly positive in the adjacent interstitium. On the other hand, type IV collagen was found weakly in the tubular basement membrane (TBM) in control cases. In DN, increased immunostaining for both type III and type IV collagens were found in the damaged tubulointenstitium (TI). To determine the sources of these collagens in TI damage, non-radioactive in situ hybridization was performed utilizing thymine-thymine (T-T) dimerized synthetic oligonucleotides complementary to either human pro alpha 1 (III) chain or pro alpha 1 (IV) chain mRNA as probe. In normal tubules, tubular epithelial cells were not uniformly but persistently positive for pro alpha 1 (IV) mRNA. Meanwhile, no specifically detectable positive hybridization signals for pro alpha 1 (III) mRNA was found in the normal tubular epithelial cells. Accelerated synthesis of both type III and type IV collagens by tubular epithelial cells was noted in TI damage in DN. From the results we concluded that excessive synthesis of both type III and type IV collagens by tubular epithelial cells might significantly contribute to the TI damage found in DN.

Collagen↗
PubMed1995

Sens-A-Ray characteristics with variations in beam quality.

This study examined the relationship between x-ray beam quality and image characteristics with the use of the Sens-A-Ray (Regam Medical Systems, Sundsvall, Sweden). To evaluate the x-ray response, properties of the image sensor, dark current and statistical noise, sensitivity, and contrast resolution were measured. Tube voltage, tube current, and exposure time were varied. Exposures were determined with the use of an ionization chamber. Pixel values beneath a lead strip were used to calculate dark current effects. Contrast was measured with pixel values from the images of a step-wedge. Dark current noise increased in proportion to exposure time. Although the sensitivity at each tube voltage was linear and proportional to the exposure, the gradient was inversely proportional to increased tube voltage. After subtraction of the dark current and statistical noise, the gradient of the sensitivity at low tube voltage remained steeper than at high tube voltages. Hence, sensitivity decreased with increased tube voltage. Sensitivity gradients at each different tube current were similar. Irrespective of exposure, contrast resolution between adjoining step-wedge steps > or = 9 mm were too small to distinguish at 50 kVp. The gray levels for each step below 12 mm in thickness were distinguishable with 90 kVp. Increased dark current noise consequent to long exposure times narrowed the available gray scale range. Lower tube voltage resulted in higher sensitivity with larger gradients than higher tube voltages.

Analog-Digital Conversion↗
PubMed1995

Reduced implantation rate associated with a subtle rise in serum progesterone concentration during the follicular phase of cycles stimulated with a combination of a gonadotrophin-releasing hormone agonist and gonadotrophin.

Our objective was to assess the effects of subtle increases in serum progesterone concentration (1.0-2.0 ng/ml) on the outcome of in-vitro fertilization (IVF), particularly on the quality of embryos, during the follicular phase of cycles stimulated with gonadotrophin-releasing hormone agonist (GnRHa) and human menopausal gonadotrophin (HMG). A total of 97 patients underwent 116 cycles of IVF and were stimulated with a combination of HMG and GnRHa. They were divided into two groups: those with a subtle progesterone rise and those with no progesterone rise. The two groups were compared with respect to serum oestradiol, progesterone, immunoreactive luteinizing hormone (I-LH), bioactive LH (B-LH), and results of IVF. The groups did not differ significantly in mean age or in total dose of HMG received. On the day that human chorionic gonadotrophin was administered, concentrations of oestradiol and progesterone were significantly higher in the subtle progesterone rise cycles than in the no progesterone rise cycles. In the no progesterone rise cycles, the percentages for embryos beyond the 4-cell stage, grade 1 embryos, and implantation rates were significantly higher than those in subtle progesterone rise cycles. The combination of GnRHa and HMG eliminated any significant rise in serum I-LH or B-LH concentration during the follicular phase, but did not suppress the subtle rise in progesterone. These results confirm our previous finding that a subtle progesterone rise adversely affects the outcome of IVF. It is also suggested that a reduction in embryo quality may influence the lower rate of implantation in subtle progesterone rise cycles.

Adult↗
PubMed1995

Utility of duplex Doppler ultrasound in evaluating portal hypertension in children.

We measured the maximal velocity of the blood flow in the main portal trunk by duplex Doppler ultrasound in children suffering from a variety of liver diseases. The maximal velocity of the main portal vein in children with chronic active hepatitis and liver cirrhosis was decreased significantly as compared to those in control children (p < 0.01). The maximal velocity of the main portal trunk and K indocyanine green (ICG) had no significant correlation (r = 0.25, n = 27). The patient with the lowest portal velocity had esophageal and gastric varices with red color sign. We conclude that the measurement of the maximal velocity of the main portal trunk with duplex Doppler ultrasound is useful in evaluating portal hypertension in children.

Adolescent↗
PubMed1995

Bacillus curdlanolyticus sp. nov. and Bacillus kobensis sp. nov., which hydrolyze resistant curdlan.

Taxonomic characteristics of seven bacterial strains which were isolated from soil and hydrolyze resistant curdlan were studied. These bacteria were aerobic, spore-forming rods, contained menaquinone 7 as a major quinone, contained anteiso-C15:0 and iso-C16:0 as major cellular fatty acids, had guanine-plus-cytosine contents of 50 to 52 mol%, and could be divided into two groups on the basis of physiological and chemotaxonomic characteristics and DNA-DNA hybridization data. We propose the following two new species: Bacillus curdlanolyticus for strains YK9, YK121, YK161, YK201, and YK203, with type strain YK9 (= IFO 15724); and Bacillus kobensis for strains YK205 and YK207, with type strain YK205 (= IFO 15729).

Aerobiosis↗
PubMed1995

In vivo and in vitro trans-cleavage activity of hepatitis C virus serine proteinase expressed by recombinant baculoviruses.

By the use of recombinant baculoviruses, the trans-cleavage of hepatitis C virus (HCV) non-structural polyprotein was studied. The viral serine proteinase encoded by the NS3 gene was expressed efficiently in insect cells infected with a baculovirus recombined with HCV cDNA corresponding to amino acids 1046-1243 and the signal sequence of the rabies virus G protein. Coinfection studies showed the in vivo trans-cleavage activity of the expressed protein by the use of a recombinant producing NS5 as a substrate. We also found that the partially purified NS3 serine proteinase prepared from the recombinant-infected cells could cleave NS5A/5B substrate. Characterization of the proteinase obtained wil provide basic knowledge on processing of the HCV polyprotein.

Amino Acid Sequence↗
PubMed1995

Characterization of an established human hepatoma cell line constitutively expressing non-structural proteins of hepatitis C virus by transfection of viral cDNA.

A human hepatoma cell line constitutively expressing proteins of hepatitis C virus (HCV) was established by transfection with cDNA encoding part of the virus nonstructural (NS) genome region. Proteins consistent with authentic processing at NS3/NS4A, NS4A/NS4B and NS4B/NS5A were identified. Pulse-chase experiments indicated that the cleavage between NS3 and NS4A occurred first and cleavage at other sites followed. Expression of specific surface antigens in response to the presence of HCV proteins was analysed by flow cytometry. A significant increase in CD26 expression was observed in cells expressing the HCV proteins. CD26 plays an important role in cellular signal transduction. Its upregulation in response to the presence of HCV proteins may play a role in viral pathology.

Base Sequence↗
PubMed1995

Association of the acral type of pustular psoriasis, Sjögren's syndrome, systemic lupus erythematosus, and Hashimoto's thyroiditis.

We describe a case of a 53-year-old Japanese female suffering from Sjögren's syndrome, systemic lupus erythematosus, and Hashimoto's thyroiditis who developed pustules, erythema, and erosions on her fingers and toes. The histological specimen showed psoriatic changes. Indirect immunofluorescent study using anti-human IL (interleukin)-8 antibody produced positive staining patterns in the lesional epidermis. These findings suggested the diagnosis of acral pustular psoriasis. Diaminodiphenylsulfone at 75 mg orally daily for 20 days and the application of 0.12% betamethasone valerate ointment led to gradual improvement.

Female↗
PubMed1995

Late-onset focal dermal elastosis: clinical and histological features.

We describe two patients with lesions clinically resembling pseudoxanthoma elasticum and histologically exhibiting focal elastosis, with normal-appearing elastic fibres in the mid- and deep dermis. We consider that these skin lesions represent a previously undescribed entity, whose pathogenesis appears to be related to the ageing process.

Aged↗
PubMed1995

Yolk sac tumour of the ear.

We report the second known case of yolk sac tumour of the external auditory canal, occurring in an eight-month-old girl. The excised tumour demonstrated histopathological and immunohistochemical features identical to those of yolk sac tumours of gonadal origin. The tumour was aneuploid by flow cytometry. The patient received chemotherapy post-operatively and has had no evidence of disease 13 months after surgery.

Ear Canal↗
PubMed1995

A new monoclonal antibody (IE8) reactive with dendritically shaped cells in the human tonsil.

A new monoclonal antibody (mAb), 1E8 (IgG1, kappa), was obtained from a hybridoma prepared by fusion of mouse myeloma cells (NS-1) with splenic cells of mice immunized with a human B blastic malignant lymphoma cell line, HPE-Ret-3 (Ret-3). The mAb showed a reactivity unrestricted to a specific cell lineage on flow cytometrical analysis of the reactivity with human lympho-hematopoietic cell lines. In peripheral blood, 1E8 reacted with the cells of all lineage, that is, lymphocytes, monocytes, granulocytes and platelets, even though its intensity was very low by immunohistochemistry. Immunohistochemical examination of human tonsil with 1E8 showed a characteristic staining pattern. Positive cells scattered in follicular (mantle zone and germinal center), parafollicular (T-dependent area), subepithelial and interstitial connective tissue areas. These positive cells seemed to be categorized into dendritically shaped cells (DSC), including dendritic cells (DC) and a subpopulation of macrophages in follicles, interdigitating cells (IDC) and irregularly shaped mononuclear cells. The localization of 1E8 antigen staining was similar to that of integrin CD11c, although its distribution on hematopoietic cell lines did not coincide with that of 1E8 antigen. Immunobiochemical studies showed that 1E8 bound two cell surface proteins with molecular size of 70,000-90,000 and 35,000 Da each. Consequently, 1E8 antigen might be a novel marker of DSC.

Animals↗
PubMed1995

Adult hepatoblastoma: case report and review of the literature.

We report a case of hepatoblastoma in a 24-year-old woman. The tumour was removed by an extended right lobectomy after transcatheter hepatic arterial embolization. A survey of the literature revealed 31 cases of adult hepatoblastoma. According to these reports there are no characteristic clinical features of the tumour, making a correct diagnosis before surgery or autopsy extremely difficult. Complete removal of the tumour is the only treatment which is potentially curative provided that lesion is confined within the liver capsule.

Adult↗