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Biomedical subjects

H Amano

Publications and source records attributed to H Amano.

At least 109 records · Page 6Linked to original sources
PubMed1996

Osteoclast function is activated by osteoblastic cells through a mechanism involving cell-to-cell contact.

We have established a method for obtaining an enriched preparation of functionally active osteoclast-like multinucleated cells (enriched OCLs) from co-cultures of mouse primary osteoblasts and bone marrow cells. Using these enriched OCLs, the effect of osteoblastic cells on osteoclast function was examined in two assays: a pit formation assay and an assay for actin ring formation. The enriched OCLs cultured for 24 h on dentine slices formed only a few resorption pits. When various numbers of primary osteoblasts were added to the enriched OCLs, the areas of the resorption pits increased proportionally to the number of osteoblasts added. Like primary osteoblasts, the established cell lines of osteoblastic cell (MC3T3-E1 and KS-4) and bone marrow-derived stromal cells (MC3T3-G2/PA6 and ST2) potentiated the pit formation caused by enriched OCLs. In contrast, the fibroblastic cell lines (NIH3T3 and C3H10T1/2) and the myoblastic cell line (C2C12) failed to activate OCL function. When cell-to-cell contact between MC3T3-E1 cells and enriched OCLs was prevented, only a few resorption pits were formed. Pit formation by enriched rat osteoclasts placed on dentine slices was also stimulated by adding MC3T3-E1 cells. Actin ring formation and pit forming activity were well correlated in either culture of enriched mouse OCLs or authentic rat osteoclasts on dentine slices. These results indicate that osteoclast function is activated by osteoblastic cells-through a mechanism involving cell-to-cell and/or cell-to-matrix contact.

Animals↗
PubMed1996

Pathogenicity of Haemophilus parasuis serovars 4 and 5 in contact-exposed pigs.

The pathogenicities of Haemophilus parasuis strains SW124 (serovar 4) and Nagasaki (serovar 5) were examined by contact-exposure of specific pathogen-free (SPF) pigs. Ten pigs were divided into three groups. Two of four pigs in the first group were inoculated intranasally (IN) with 2 x 10(8) CFU of strain SW124, and the other two pigs were mingled with these IN-exposed ones. All the four pigs were subclinically infected in this group. The four pigs of the second group were likewise exposed to strain Nagasaki (two IN-inoculated pigs with 3 x 10(8) CFU of strain Nagasaki). All four pigs in this group died of Glässer's disease. Two pigs kept as controls showed neither abnormality nor positive H. parasuis isolation.

Animals↗
PubMed1996

Cardiogenic shock following recombinant alpha-2b interferon therapy for chronic hepatitis C. A case report.

A 57-year-old woman with chronic hepatitis C was treated with alpha-2b interferon (IFN). Forty-five days after the initiation of IFN therapy, she developed cardiogenic shock. Acute perimyocarditis as a cause of cardiogenic shock was clinically suspected by the findings of complete atrioventricular block, regional wall motion abnormality and pericardial effusion. Since IFN therapy may induce cardiogenic shock in some patients, it is important to carefully monitor patients under treatment with IFN for abnormal cardiac signs.

Acute Disease↗
PubMed1996

Adverse effects of interferon on the cardiovascular system in patients with chronic hepatitis C.

The therapeutic effects of interferon in chronic hepatitis C and many of its adverse effects have been well documented. However, there are only a few reports regarding its adverse effects on the cardiovascular system. The aim of this study was to clarify the clinical features of the adverse effects of interferon on the cardiovascular system in patients with chronic hepatitis C. We monitored 295 patients with chronic active hepatitis C during 312 courses of interferon therapy and for 1 year after the end of treatment for the presence of cardiovascular adverse effects. We found 6 patients with cardiovascular adverse effects during interferon therapy and 4 more patients within 1 year after the end of therapy (10/312, 3.2%). The adverse effects of interferon on the cardiovascular system included arrhythmia (n = 4), ischemic heart disease (n = 4) and myocardial disease (n = 2). None of the clinical factors, including history of cardiovascular disease, were related to these cardiovascular adverse effects. In all instances the patient's condition improved after discontinuation of interferon and adequate therapy. The cardiovascular adverse effects of interferon occurred frequently in patients with chronic hepatitis C, even after the end of therapy and they were unpredictable. Thus, all patients undergoing interferon therapy should be monitored not only during but also after the end of treatment.

Arrhythmias, Cardiac↗
PubMed1996

Sarcoidosis after interferon therapy for chronic active hepatitis C.

Sarcoidosis is characterized by multisystemic granulomatous lesions of unknown etiology. A 62-year-old woman developed sarcoidosis after treatment with alpha-2a interferon (IFN) for 24 weeks (total dose: 522 million units) for chronic hepatitis C. She developed complete atrioventricular block and multiple noncaseating granulomatous lesions in the lung. IFN therapy, which may disturb cellular immune activation in some patients, may have contributed to the onset and progression of sarcoidosis.

Antiviral Agents↗
PubMed1996

Generalized morphea with vascular involvement. A case report and disaccharide analysis of the skin glycosaminoglycans.

We report a 69-year-old man with severe generalized morphea, who showed over 80% of skin involvement, while the internal organs were not affected. We performed histological examinations and analysis of skin disaccharides constituting chondroitinase-digestible glycosaminoglycans in the center and periphery of the sclerotic lesions and the clinically uninvolved skin. In both the central and peripheral parts of the sclerotic lesions, sclerotic fibrosis and a dense perivascular cell infiltration, consistent with morphea, were seen in the entire dermis and subcutis. Furthermore, various vascular changes were observed, such as endothelial cell swell, thickened basement membrane and obstruction of vascular lumen in the fat lobules. In the clinically uninvolved skin, interstitial edema was prominent along with a slight perivascular cell infiltration. On disaccharide analysis, the increase in the amount of delta Di-4S(DS), the main disaccharide unit of dermatan sulphate, delta Di-6S and delta Di-6S, the main disaccharide units of chondroitin sulphate, and the decrease in delta Di-HA, which is derived from hyaluronate, were found not only in the sclerotic lesions but also in the clinically uninvolved skin, though less prominent. These alterations were consistent with systemic sclerosis, suggesting a close relationship between severe forms of generalized morphea and systemic sclerosis.

Aged↗
PubMed1996

[Comparison of bone mineral levels in healthy Japanese perimenopausal women measured by dual energy X-ray absorptiometry and ultrasound methods].

One hundred and seventy Japanese perimenopausal women, 44 to 65 years old (average 55.3), living in the Tokyo metropolitan area were evaluated for bone minerals by two methods of measurement--DXA (dual energy x-ray absorptiometry) measured at the 2nd-4th lumbar spine and three areas of proximal femur, and US (ultrasound bone densitometry) measured at the calcaneal area of the foot. Menopausal status was determined by interview, and anthropometric measurements, grip strength and various foot measurements including length, breadth, girth, area, and angles were taken. The relationship between these physical factors and bone minerals measured by DXA and US was considered in comparisons of evaluations of bone mineral condition by these two different methods. The results were as follows: 1) The means of bone mineral density (BMD) at four sites by DXA and of broadband ultrasound attenuation (BUA) by US decreased with age significantly in a graded fashion. The mean of speed of sound (SOS) by US, however, did not show a significant decrease by age. 2) All measurements but one (SOS by US) showed significant differences among three groups of menopausal status (premenopause, < 6 years after menopause, and > or = 6 years after menopause) by ANOVA. 3) Concerning the relationship between physical variables and bone measurements, all measurements for bone mineral showed significant correlations with body weight (positive) and age (negative) except SOS by US. Grip strength had significantly positive correlations to all bone measurements. BUA by US showed strong correlations with several of the foot measurements. 4) Correlations between bone measurements by DXA and US, were all strong and positive particularly in the combinations within the measurement by DXA. 5) Multiple regression analysis of the physical variables to each bone measurement as the dependent variable, showed significant relationship of age (negative) and body weight or BMI (positive) to each bone measurements except for SOS. The foot area remained significant for BUA. The significant relationship of combinations of physical factors that persisted for US were somewhat different from those in DXA. These results indicate that the level of accuracy of measurements of bone mineral by ultrasound may not necessarily be equivalent to that of dual energy x-ray absorptiometry measurements and must be utilized with caution especially in risk factor analysis of osteoporosis.

Absorptiometry, Photon↗
PubMed1996

[The effect of prostaglandin E1 on body temperature, catecholamines and stress hormones during prolonged surgery].

The effects of prostaglandin E1 (PGE1) on body temperature, catecholamines and stress hormones were evaluated in 10 patients undergoing elective prolonged surgery over 12 hours. PGE1 (0.03 microgram.kg-1.min-1) was administered in 5 patients and was not administered in 5 patients. Deep skin-surface temperature gradients were 5.1 +/- 2.3 degrees C in PGE1 non-administered group and 0.8 +/- 0.9 degree C in PGE1 administered group (P < 0.05). Pharyngeal-skin surface temperature gradients were 8.8 +/- 2.1 degrees C in PGE1 non-administered group and 1.5 +/- 1.5 degrees C in PGE1 administered group (P < 0.05). There were no significant differences between the two groups in respects to catecholamines, stress hormones, lactate level and blood sugar. PGE1 0.03 microgram.kg-1.min-1 is effective in maintaining peripheral circulation without causing body temperature changes during prolonged surgery.

Adrenocorticotropic Hormone↗
PubMed1996

[The Human Menopausal Gonadotrophin Reference Standard (Control 961) of the National Institute of Health Sciences].

Raw human menopausal gonadotrophin (HMG) material was examined for preparation of the "Human Menopausal Gonadotrophin Reference Standard (Control 961)". The candidate material was assayed its follicle stimulating hormone (FSH) activity and luteinizing hormone (LH) activity against the 3rd International Standard for FSH and LH, urinary (71/264) by the augmented ovarian weight gain assay and the seminal vesicle weight gain test, respectively. The potency of the new standard was defined as 56 international units of FSH activity per mg and 61 international units of LH activity per mg as the result of 13 and 5 assays, respectively, in four collaborative laboratories.

Animals↗
PubMed1995

Further evaluation of the developmental toxicity of tributyltin chloride in rats.

The objective of this study was to further evaluate the developmental toxicity of tributyltin chloride (TBTCl) in rats. Pregnant rats were given TBTCl by gastric intubation at a dose of 25, 50 or 100 mg/kg on days 7-9, days 10-12 or days 13-15 of pregnancy. A significant increase in the incidence of post-implantation loss was found in the groups treated with TBTCl on days 7-9 at 25 and 50 mg/kg and on days 10-12 at 100 mg/kg, but not in the groups treated with TBTCl on days 13-15. No significant increase in the incidence of malformed fetuses was observed after treatment with TBTCl on days 7-9. A significant increase incidence of malformed fetuses was detected when TBTCl was given on days 10-12 at 100 mg/kg and on days 13-15 at 25, 50 and 100 mg/kg. The most predominant malformation was cleft palate. It could be concluded that the manifestation of deviant development induced by TBTCl varies with the developmental stage at the time of administration and TBTCl possesses teratogenic potential with developmental phase specificity.

Abnormalities, Drug-Induced↗
PubMed1995

Comparative developmental toxicity of n-butyl benzyl phthalate and di-n-butyl phthalate in rats.

n-Butyl benzyl phthalate (BBP) and di-n-butyl phthalate (DBP) were evaluated and compared for their developmental toxic potential. Pregnant rats were given either BBP or DBP by gastric intubation at a dose of 0.75, 1.0 and 1.25 g/kg on days 7-9, days 10-12 and days 13-15 of pregnancy. Regardless of the days of treatment, a significantly increased incidence of postimplantation loss was found at all doses of BBP and DBP. While treatment with BBP and DBP at doses of 0.75 g/kg and above on days 7-9 or days 13-15 resulted in a significant increase in the incidence of fetuses with malformations, no increase in the incidence of malformed fetuses was found after treatment with BBP and DBP on days 10-12. The incidences of postimplantation loss and malformed fetuses increased as the doses of BBP and DBP were increased. Deformity of the vertebral column and ribs commonly occurred after treatment with BBP and DBP on days 7-9. Cleft palate and fusion of the sternebrae were predominantly observed after treatment with BBP and DBP on days 13-15. The similarity in dependence of gestational days of treatment on the manifestation of developmental toxicity and on the spectrum of fetal malformations caused by BBP and DBP suggests that they may act by the same mechanism, possibly via a common metabolite of these two parent compounds.

Abnormalities, Drug-Induced↗
PubMed1995

Downregulation of colony-stimulating factor-1 (CSF-1) binding by CSF-1 in isolated osteoclasts.

Colony-stimulating factor-1 (CSF-1), also called macrophage colony-stimulating factor, is the growth factor for the cells of the mononuclear phagocytic system. Furthermore, CSF-1 is essential in osteoclastogenesis and also affects mature osteoclasts. The receptor for CSF-1 was demonstrated on cells of the osteoclast lineage, with highest levels on the mature cells. This study investigated whether the binding of CSF-1 to isolated rat osteoclasts is modulated by the growth factor itself. Exposure of osteoclasts to CSF-1 for 1 hour virtually abolished binding of the growth factor. After removal of CSF-1, binding sites were restored within 4 hours. This recovery was blocked by cycloheximide, indicating the dependence on new protein synthesis for reexpression of receptors on the cell surface. The observed downregulation of CSF-1 binding sites might be a mechanism to control the effects of the growth factor on mature osteoclasts.

Animals↗
PubMed1995

Developmental toxicity evaluation of mono-n-butyl phthalate in rats.

Mono-n-butyl phthalate (MBuP) was evaluated for developmental toxicity in Wistar rats. Rats were given MBuP by gastric intubation at 0, 250, 500 or 625 mg/kg on days 7-15 of pregnancy. Significant decreases in the maternal body weight gains and food consumption during pregnancy were found at 500 and 625 mg/kg. Significant increase in the incidence of postimplantation loss per litter and decreases in the number of live fetuses per litter and fetal weight were also detected at 500 mg/kg and above. The incidence of fetuses with malformations in the 500 and 625 mg/kg groups was higher than that in the control group. Cleft palate, deformity of the vertebral column and dilatation of the renal pelvis were frequently observed.

Abnormalities, Drug-Induced↗
PubMed1995

The effects of an algal polysaccharide from Gloiopeltis tenax on transplantable tumors and immune activities in mice.

Funoran (an algal polysaccharide from Gloiopeltis tenax) significantly inhibited the growth of Ehrlich ascites carcinoma and solid Ehrlich, Meth-A fibrosarcoma, and Sarcoma-180 tumors. In tumor-bearing mice, funoran significantly induced the enhancement of delayed-type hypersensitivity response to sheep red blood cells. When given intraperitoneally, funoran increased the spleen weight of mice. Morphological observations indicated that funoran augmented the transformation from lymphocytes to plasma cells in the spleen. In addition, changes in the T-cell subsets in the spleen, thymus, and peripheral blood were measured by flow cytometry. The results showed that the percentages of L3T4+ and Lyt 2+ T-cells were markedly increased in the peripheral blood. The percentages of asialo CM1+ cells in the thymus and peripheral blood were also significantly increased. Our results suggest that the antitumor effect of funoran is related to the augmentation of T-helper, T-cytotoxic, and NK cells.

Adjuvants, Immunologic↗
PubMed1995

Identification and characterization of the thymidine kinase gene of Yaba virus.

DNA of Yaba virus, a member of the poxviruses, was mapped by cross-hybridization between fragments of various restriction enzymes. The genome was approximately 135 kb in length and possessed two characteristic features of poxviruses: cross-links and inverted terminal repeats at both termini. Hybridization of fragments of Yaba virus DNA to known vaccinia virus DNA fragments indicated that the thymidine kinase (TK) gene mapped within the 0.9 kb XhoI-HincII fragment between 52.5 and 53.5 kb from the left end of the genome. The fragment could rescue the TK+ phenotype in TK- cells preinfected with a TK vaccinia virus mutant. Nucleotide sequencing of the fragment revealed an ORF capable of encoding 181 amino acids. The sequence TAAAAATGAAAAATTA upstream of the ORF was considered to be the promoter and the downstream sequence TTTTTAT to be the early transcription termination signal. These sequences are in good accord with the consensus regulatory sequences for the expression of early genes of other known poxviruses. The amino acid sequence similarity among the poxvirus TK genes suggests that Yaba virus is most closely related to swinepox virus and less similar to fowlpox virus.

Amino Acid Sequence↗
PubMed1995

Role of nitric oxide in the control of blood pressure in young and adult spontaneously hypertensive rats.

1. The depressor response to sodium nitroprusside (SNP) and the pressor response to Nomega-nitro-L-arginine methyl ester (L-NAME) were investigated in anaesthetized and ganglion-blocked 6 week old (young) and 20 week old (adult) spontaneously hypertensive rats (SHR), and the results were compared with those in age-matched normotensive Wistar-Kyoto (WKY) rats. 2. SNP produced a dose-dependent decrease of the mean blood pressure (BP) in both strains, and no differences in vascular sensitivity to SNP were observed between the strains. 3. L-NAME caused dose-dependent pressor responses in both strains. The sensitivity and the maximal response to L-NAME in SHR were significantly greater than those in age-matched WKY (P< 0.05 or 0.01; t-test, 13 d.f. in both ages). However, there were no significant differences in the responses between ages in each strain. 4. Acute reduction of BP induced by 7-O-ethylfangchinoline did not affect the responses to SNP and L-NAME in the adult SHR. 5. These results indicate that a greater amount of NO is tonically released in SHR and that its contribution to BP control is greater in SHR than in WKY, whereas vascular sensitivity to NO does not differ between the strains. In addition, acute changes in BP do not affect the degree of dependency on NO for BP control.

Aging↗
PubMed1995

Antihypertensive effects, determined by a telemetry method, of trichloromethiazide and 7-O-ethylfangchinoline, a derivative of tetrandrine, in spontaneously hypertensive rats.

1. The antihypertensive effects of 10 mg/kg trichloromethiazide (TCM), 10 mg/kg 7-O-ethylfangchinoline (7-O-EFC) and the combination of these drugs given orally once daily for 2 weeks were investigated by measuring the blood pressure (BP), heart rate (HR) and activity in conscious, freely moving spontaneously hypertensive rats (SHR) fitted with a telemetry device. 2. Clear diurnal rhythms of the HR and activity in synchrony with the light/dark cycle were observed during therapy, whereas the BP rhythm was obscure. 3. Alone, TCM and 7-O-EFC produced slight and insignificant reductions of 24h mean BP, whereas in combination they produced an additive and significant BP reduction, compared with the vehicle-treated controls, from the third day of therapy. The BP reduction induced by the combination of these drugs during the dark phase was more marked than that during the light phase. 4. None of the drug therapies affected the HR and activity diurnal rhythms. 5. The results of the present study demonstrate that the telemetry method is useful for monitoring the antihypertensive effects of drugs in SHR under physiological conditions with minimal stress.

Alkaloids↗