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Biomedical subjects

H Tamura

Publications and source records attributed to H Tamura.

At least 91 records · Page 5Linked to original sources
PubMed1999

Immunological aspects of chitin and chitin derivatives administered to animals.

Chitosan amino groups are recognized by the immune system. Therefore, every derivative of chitin should be assayed immunologically if biomedical applications are sought. Macrophages are activated to various extents by chitin derivatives. Deacetylated chitin (30% deacetylation) and chitin sulfate stimulate the production of circulating antibodies. Accumulation of carboxymethyl chitin takes place in granulocytes and macrophages. These polysaccharides activate complement in analogy to zymosan. Intraperitoneal injection of N-acetylchitohexaose inhibits the growth of tumor cells and pathogens on a similar level as that of lentinan.

Animals↗
PubMed1999

Identification of the US3 gene product of BHV-1 as a protein kinase and characterization of BHV-1 mutants of the US3 gene.

We have identified the product of the US3 gene of bovine herpes virus type 1 (BHV-1), which is homologous to the herpes simplex virus type 1 (HSV-1) US3 protein kinase (PK) gene. The antibodies against the BHV-1 US3 gene product reacted with a 58 kDa polypeptide in BHV-1 infected cells and the 58 kDa polypeptide purified by immuno-precipitation demonstrated PK activity. Recent reports indicating that the US3 gene of HSV-1 is involved in the blockage of apoptosis in virus infected cells. As to the apoptosis in BHV-1 infected cells, we found following: (1) no apoptosis was observed in cells infected with wild type BHV-1 and the US3 mutants (2) the apoptosis induced by the osmotic shock of sorbitol treatment was blocked when cells were infected by the wild type BHV-1 (3) the US3 mutants of BHV-1 blocked the apoptosis of sorbitol treated cell, but the suppressive effect was delayed relative to that of wild type BHV-1 (4) the other BHV-1 mutants, with the intact US3 gene but with some other non-essential gene (genes) deleted behaved similar way to the US3 mutant. It is concluded that the US3 gene of BHV-1 is not directly involved in the blockage of apoptosis in infected cells.

Animals↗
PubMed1999

Growth of moulds inoculated into commercial mineral water.

The growth of mould spores of Penicillium sp. and Cladosporium sp. inoculated in a commercial mineral water product was studied. The strains had been isolated as fungal foreign bodies in commercial mineral waters. In product A, which was not originally sterilized and was contaminated with psychrophilic bacteria, the inoculated mould spores of the strains did not grow; no increases in viable colony counts or beta-glucans concentration in the samples were observed during storage. In a sterilized product A, inoculated spores of the strains grew into visible foreign bodies. The viable colony counts and the beta-glucans concentration in the samples increased during storage. These results showed that in a sterilized mineral water product, mould spores could grow into visible foreign bodies.

Cladosporium↗
PubMed1999

Sonographic evaluation of antepartum development of fetal gastric motility.

OBJECTIVE: Little is known about the development of fetal gastric motility and emptying. The aim of this study was to evaluate the development of gastric motility sonographically in the human fetus. METHODS: The motility and peristalsis of the fetal stomach were sonographically studied in 76 normal fetuses at 12-39 weeks of gestation. Fetal gastric motility was assessed by videotaping real-time ultrasonic images of the stomach for periods of 60 or more minutes. RESULTS: Gastric peristalsis appeared as early as 14 weeks of gestation, and was detected in all fetuses by 23 weeks. The frequency of peristaltic waves was constant, and was 2.2-3 times per minute at 14-39 weeks of gestation. The onset of fetal gastric peristalsis was sporadic and the period with no peristaltic waves was dominant before 24 weeks of gestation. Fetal gastric peristalsis increased and consolidated into long-term clusters from 24 weeks of gestation. The mean duration of peristalsis increased from 4.1 +/- 1.2 min (n = 6) at 20-23 weeks to 14.1 +/- 3.2 min (n = 14) at 32-35 weeks of gestation, and remained constant thereafter. CONCLUSIONS: Fetal gastric motility was quantified and its development during pregnancy was assessed in this study. There was a critical point of development at around 24-25 weeks of gestation when grouped peristalsis was observed in all fetuses.

Embryonic and Fetal Development↗
PubMed1999

Influences of Helicobacter pylori on serum pepsinogen concentrations in dialysis patients.

BACKGROUND: Patients with impaired renal function have been known to have elevated concentrations of serum pepsinogens, which are raised by Helicobacter pylori infection of the stomach. The present study was performed to examine the effect of H. pylori infection on serum pepsinogen concentrations in dialysis patients. METHODS: Forty nine patients on dialysis and 48 subjects with no known kidney disease were examined for upper gastroduodenal endoscopy, H. pylori infection and serum concentrations of pepsinogen I and II. The status of H. pylori infection was evaluated from results of a urease test, histology and culture of biopsy specimens of the gastric mucosa. Serum pepsinogen levels were measured by radioimmunoassay. RESULTS: Serum concentrations of pepsinogen I and II were elevated in the dialysis patients in comparison with those in the controls (277.4+/-24.2 vs 52.6+/-4.0 pg/ml, P<0.01 for pepsinogen I, and 30.2+/-2.9 vs 14.9+/-1.3 pg/ml, P<0.01 for pepsinogen II). In both the dialysis patients and controls, those with H. pylori infection had significantly higher concentrations of serum pepsinogen I and II and a lower ratio of pepsinogen I to pepsinogen II than those without infection. Among the controls, 15 of 25 subjects with atrophic gastritis had a pepsinogen I/pepsinogen II ratio < or = 3.0, while only two out of 17 patients on dialysis fell into this range. CONCLUSIONS: We conclude that H. pylori status should be taken into account when serum pepsinogen concentrations are evaluated in dialysis patients.

Female↗
PubMed1999

Roles of asp126 and asp156 in the enzyme function of sphingomyelinase from Bacillus cereus.

To elucidate the roles of conserved Asp residues of Bacillus cereus sphingomyelinase (SMase) in the kinetic and binding properties of the enzyme toward various substrates and Mg2+, the kinetic data on mutant SMases (D126G and D156G) were compared with those of wild type (WT) enzyme. The stereoselectivity of the enzyme in the hydrolysis of monodispersed short-chain sphingomyelin (SM) analogs and the binding of Mg2+ to the enzyme were not affected by the replacement of Asp126 or Asp156. The pH-dependence curves of kinetic parameters (1/Km and kcat) for D156G-catalyzed hydrolysis of micellar SM mixed with Triton X-100 (1:10) and of micellar 2-hexadecanoylamino-4-nitrophenylphosphocholine (HNP) were similar in shape to those for WT enzyme-catalyzed hydrolysis. On the other hand, the curves for D126G lacked the transition observed for D156G and WT enzymes. Comparison of the values and the shape of pH-dependence curves of kinetic parameters indicated that Asp126 of WT SMase enhances the enzyme's catalytic activity toward both substrates and its binding of HNP but not SM. The deprotonation of Asp126 enhances the substrate binding and slightly suppresses the catalytic activity toward both substrates. Asp156 of WT SMase acts to decrease the binding of both substrates and the catalytic activity to HNP but not SM. From the present study and the predicted three-dimensional structure of B. cereus SMase, Asp126 was thought to be located close to the active site, and its ionization was shown to affect the catalytic activity and substrate binding.

Aspartic Acid↗
PubMed1999

Molecular cloning, expression and characterization of a phenol sulfotransferase cDNA from mouse intestine.

A sulfotransferase (ST) cDNA was isolated from a mouse intestinal cDNA library using a probe which was generated by reverse transcription (RT)-PCR based on the conserved amino acid sequences of the ST molecules. The isolated cDNA (1.1 kb) contained an 858 bp open reading frame encoding a 286 amino acid polypeptide with molecular weight of 33439. The deduced amino acid sequence shares 55.1% and 40.2% identity with mouse liver aryl/phenol (mSTp1) and alcohol (mSTa1 or mSTa2) STs, respectively, and it is highly similar to those of rat and human liver phenol ST (P-ST) isozymes, ST1B1 (87.8%) and ST1B2 (71.0%), respectively. RT-PCR analyses showed abundant expression of the P-ST mRNA in the intestine as well as in the liver in the mouse tissues examined (brain, heart, intestine, kidney, liver and lung) of both sexes. E. coli-expressed enzyme is capable of catalyzing the sulfation of 2-naphthol at Km = 3.3 microM and Vmax = 3.33 nmol/min/mg protein and also showed sulfation activity for L-3,4-dihydroxyphenylalanine (L-DOPA) and dopamine. Among food constituents tested, tannic acid and epigallocatechin gallate strongly inhibited the P-ST activity in vitro.

Amino Acid Sequence↗
PubMed1999

Repeated 131I treatment of a residual ovarian teratoma containing malignant thyroid tissue.

A 49-year-old woman with ovarian teratoma received 131I treatment three times for an unresectable mass containing malignant thyroid tissue after surgery. Repeated 131I treatment effectively reduced serum thyroglobulin (Tg) level and tumour uptake of 131I, despite absence of any change in size of the treated tumour. Treatment did not inhibit the increase of serum CA-125 and tumour 201Tl uptake, associated with progression of a radioresistant intratumoral hyper-perfused tissue component, detected by colour Doppler ultrasound. Serum CA-125 level and tumour 201Tl uptake were not significantly changed despite temporary increases in serum Tg level after each 131I treatment. These observations indicate the importance of diagnostic measures using combined functional imaging and tumour markers in managing this rare tumour.

Biomarkers, Tumor↗
PubMed1999

Changes in interleukin-1beta mRNA expression in the rat ovary during the estrous cycle in response to lipopolysaccharide.

The changes in interleukin-1 (IL-1) beta mRNA expression and the number of macrophages were studied in the ovary during the estrous cycle in rats and after intraperitoneal injection of lipopolysaccharide (LPS, 2 mg/body) 2 hours before autopsy. IL-1beta mRNA expression was very low in the ovary, and there was no statistically significant change during the estrous cycle. Hybridization signals of IL-1beta mRNA were localized intensely in the thecal layer, moderately in the corpora lutea, and slightly in granulosa cells of the ovary during the cycle. The number of macrophages seen mainly in the hilum and interstitium significantly increased on proestrus compared with other estrous days. LPS significantly increased IL-1beta mRNA expression on each day with the highest response to LPS at 1500 h on proestrus, and caused an increase in the number of macrophages in the ovary within 2 hours. These results indicate that IL-1beta mRNA expressions are low during the estrous cycle in rats, and proestrus is the day of maximal IL-1beta synthesis in response to LPS. The increase in IL-1beta synthesis caused by LPS might be due to at least the influx of macrophages into the ovary.

Animals↗
PubMed1999

The position and size of radiological nephrogram in Japanese preschool children.

The early detection of retroperitoneal masses in children, such as neuroblastoma, Wilm's tumor, hydronephrosis and cystic renal diseases, has a great clinical importance for the improvement of their prognosis. The kidney is often affected in its size or position by these lesions, and occasionally allows clinicians to find a clue to reach the correct diagnosis before the patient become symptomatic. Since we had no clinically available nomogram on the position and the size of the kidney in Japanese children, we measured the size and position of the kidneys on plain abdominal x-rays in 347 Japanese children in preschool years with a special attention to their relationship with the spine. As a result, the nomogram showed age dependent growth of the kidneys keeping almost the same ratio with the spine, while the distance between the upper pole of the kidney and the spine remained less than 10 mm in all age groups. Our nomogram may be useful not only for picking up the malposition of the kidneys but also for the follow up of the patients with chronic renal diseases affecting the growth of the kidneys.

Aging↗
PubMed1999

Clinical study of the pumping pressure changes in the temporomandibular joint space before and after arthroscopic surgery.

When arthroscopy of the temporomandibular joint (TMJ) is performed, we often observe differences in the resistance of hydraulic pressure during intra-articular pumping. It can be speculated that intra-articular adhesion and contracture of the capsule and ligament may cause these differences in resistance. In order to measure the changes in intra-articular hydraulic pressure before and after arthroscopic ablation surgery, seven cases were examined by balloon pumping technique. We concluded that the values of intra-articular hydraulic pressure are implicated in the severity of the internal derangement of TMJ.

Angioplasty, Balloon↗
PubMed1999

Metachronous multiple carcinoma of lip after surgery for gingival carcinoma: a case report.

A case of multiple carcinoma of the lower lip probably induced by repeated bite trauma due to lack of sensation is reported. A reduction in immunocompetence by carboplatin (CBDCA) might be an additional condition for the carcinogenesis. This case suggests that the reconstruction of the sensory nerve is important after resection of a malignant tumor of the head and neck region.

Aged↗
PubMed1999

[Histologic occurrence of Barrett's carcinoma].

It is generally agreed that the diagnosis of Barrett's esophagus is justified when the columnar epithelium 3 cm or more from the E-C junction is involved. Microscopically, the epithelium has three distinct appearances: (1) gastric fundic type; (2) junctional type: and (3) specialized columnar type. In mucin histochemistry in 6 cases of Barrett's carcinoma, 5 cases of Barrett's esophagus were positive for HID-AB. Four cases of Barrett's carcinoma were also positive. These results suggest that Barrett's carcinoma developed from the specialized columnar type of Barrett's esophagus.

Barrett Esophagus↗
PubMed1999

Water channel AQP-1 in the primary cell culture of rat peritoneum.

To analyze the regulation of water channels in the peritoneum, we tried to establish a primary mesothelial cell culture system. Male Sprague-Dawley rats weighing about 250 g were anesthetized, and 10 mL of phosphate-buffered saline (PBS) containing 0.25% trypsin and 1 mmol/L ethylenediamine tetraacetic acid (EDTA) was infused into the peritoneal cavity for 15 minutes. Sediments from the recovered fluid were cultured in medium M199 supplemented with 10% fetal bovine serum (FBS). The culture was succeeded 4-6 times before experiments commenced. After exposure to the test medium, RNA was extracted and subjected to reverse transcriptase polymerase chain reaction (RT-PCR) for 10-19 cycles, then was measured by Southern blot analysis with a digoxin-labeled probe. Cultured cells were positively stained with mouse monoclonal anti-cytokeratin antibody, confirming their characteristics as mesothelial cells. Aquaporin-1 (AQP-1) message in the cultured cells increased with increases in glucose and mannitol concentrations when beta-actin message was used as an internal control. Tranexamic acid effected no change in AQP-1 message in the cultured mesothelial cells. This system offers potential as a simple approach to test the effects of osmolytes, cytokines, and vasoactive hormones on aquaporin expression and water transport in the peritoneum.

Animals↗
PubMed1998

Mg2+ binding and catalytic function of sphingomyelinase from Bacillus cereus.

The modes of Mg2+ binding to SMase from Bacillus cereus were studied on the basis of the changes in the tryptophyl fluorescence intensity. This enzyme was shown to possess at least two binding sites for Mg2+ with low and high affinities. The effects of Mg2+ binding on the enzymatic activity and structural stability of the enzyme molecule were also studied. The results indicated that the binding of Mg2+ to the low-affinity site was essential for the catalysis, but was independent of the substrate binding to the enzyme. It was also indicated that the alkaline denaturation of the enzyme was partly prevented by the Mg2+ binding, whereas no significant protective effect was observed against the denaturation by urea. The pH dependence of the kinetic parameters for the hydrolysis of micellar HNP and mixed micellar SM with Triton X-100 (1:10), catalyzed by SMase from B. cereus, was studied in the presence of a large amount of Mg2+ to saturate both the low- and high-affinity sites. The pH dependence curves of the logarithm of 1/Km for these two kinds of substrates were similar in shape to each other, and showed a single transition. On the other hand, the shapes of the pH dependence curves of the logarithm of kcat for these two kinds of substrates were different from each other. The pH dependence curve for micellar HNP showed three transitions and, counting from the acidic end of the pH region, the first and third transitions having tangent lines with slopes of +1 and -1, respectively. On the other hand, the curve for mixed micellar SM with Triton X-100 showed one large transition with a slope of +1 (the first transition) and a very small transition (the third transition). On the basis of the present results and the three-dimensional structure of bovine pancreatic DNase I, which has a primary structure similar to that of B. cereus SMase, we proposed a catalytic mechanism for B. cereus SMase based on general-base catalysis.

Animals↗
PubMed1998

An automated new technique for scoring the rodent micronucleus assay: computerized image analysis of acridine orange supravitally stained peripheral blood cells.

We developed an automated image analysis system to obtain objective data for the rodent peripheral blood micronucleus assay with acridine orange (AO) supravital staining. The system was able to identify micronucleated reticulocytes (MNRETs) and to evaluate inhibition of bone marrow cell proliferation by measuring the reticular area of reticulocytes (RETs). We also developed automated equipment to produce homogeneous acridine orange-coated glass slides. This study was designed to compare automated scoring with manual scoring using 4 model clastogens and 2 mouse strains. The MNRET incidence induced by each clastogen was similar for automated and manual scoring, and there was good correlation (r=0.92) between the methods. In addition, an index of bone marrow toxicity based on the reticular area of RETs was compared to the conventional index (% of polychromatic erythrocytes (PCE) to total erythrocytes; PCE ratio) and was similar. The results indicated that our technique for computer-assisted image analysis for the micronucleus assay with AO supravitally stained peripheral blood RETs was comparable to conventional microscopic scoring, and it was superior in objectivity and statistical power.

Acridine Orange↗