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Biomedical subjects

T Harada

Publications and source records attributed to T Harada.

At least 1,099 records · Page 61Linked to original sources
PubMed1982

Bone resorption under the influence of parathyroid hormone in vitro.

Parathyroid-induced bone resorption in vitro was observed by phase contrast microscope, 16 mm time-lapse cinemicrograph, light- and electron microscope. These findings led us to the following conclusions. That is, the macrophages seem to be capable of resorbing the bone tissue, and perhaps they may degrade and digest the collagen fibers, while the osteoclasts may resorb the bone minerals. The osteoclasts are destined to extinction after about two to three weeks of life span.

Animals↗
PubMed1982

Usefulness and rapidity of screening for the toxicity and carcinogenicity of chemicals in medaka, Oryzias latipes.

The toxicity and carcinogenicity of number of chemicals, for which there are toxicity and/or carcinogenicity data in mouse and rat, were tested in medaka, a small aquarium fish (Oryzias latipes). The water-soluble chemicals were dissolved in the water and the water-insoluble chemicals were incorporated into the diet. Observation for 24 wk revealed induction of liver cell carcinoma by 6 chemicals; aflatoxins B1 and G1, sterigmatocystin, ortho-aminoazotoluene, methylazoxymethanol acetate and N-nitrosodiethylamine. In medaka fed PCB or DDT only preneoplastic liver cell nodules were observed. No evident carcinogenicity was found in medaka treated with 2-fluorenylamine, 2-fluorenylacetamide, DL-ethionine, luteoskyrin, ochratoxin A, phenobarbital, 1-(2-tetrahydrofuryl)-5-fluorouracil, sodium benzoate, 2,3,4,5,6-penta-O-acetyl-D-gluconyl isothiocyanate, citrinin and fusarenon X, respectively, although toxic lesions or hyperplastic changes were demonstrated histologically. These results confirm the practical utility and rapidity of the use of medaka for screening carcinogenicity and toxicity of chemicals, since neoplastic or toxic morphological changes develop rapidly following administration of relatively small quantities of test materials.

Adenoma↗
PubMed1982

[Proximal ligation of the vertebral artery for treatment of vertebral aneurysms].

Vertebral aneurysms are not necessarily rare. In general neck clipping of vertebral aneurysms is the surest method for treatment of aneurysms, but as for vertebral aneurysms, it is often difficult to clip the neck without danger, because they cross over lower cranial nerves and are often fusiform. The indication of proximal ligation of the vertebral artery for treatment of vertebral aneurysms has not yet established. This procedure in 28 cases in the literature and our 3 cases treated successfully was discussed and following results were obtained. 1) Proximal ligation of the vertebral artery was useful for prevention of a rupture of vertebral aneurysms. 2) Intracranial ligation of the vertebral artery was better than the ligation in the cervical region. 3) It was necessary for the diameter of the contralateral vertebral artery to be, at least, approximately same. 4) In order the diameter of the vertebral artery to enlarge to 1.2 times as wide as that of a preoperative state, and the blood flow in the basilar artery to be enough, it was necessary for the contralateral vertebral artery not to be sclerotic.

Adult↗
PubMed1981

Temporal bone histopathologic findings in Down's syndrome.

We report the results of a histopathologic study of 12 temporal bones from seven patients with Down's syndrome and of a dimensional study of the cochlea and the vestibular apparatuses of most of these specimens. Histopathologic study disclosed numerous abnormalities of the middle ear but only a limited number of inner ear abnormalities. The dimensional study showed that, while in the majority of cases the cochlea was shortened, most of the vestibular measurements were within the normal range. We also discuss hearing loss in patients with Down's syndrome and present our hypothesis that remnants of mesenchymal tissue in the round window niche might cause a certain degree of conductive hearing loss in such cases.

Adolescent↗
PubMed1981

An electron microscopic study of the epiretinal membrane of human eyes.

An electron microscopic study was conducted to elucidate the cell types involved in the formation of epiretinal membranes in four cases. In three cases, the specimens were provided by a vitrectomy and pigment epithelial cells (two cases) and fibrocytes (one case) represented the preponderant constituents of the membrane, whereas the membrane consisted chiefly of glial cells in the fourth case in which an eye showing this condition was obtained by enucleation.

Adult↗
PubMed1981

Representation of T cell functions in liver bearing hepatocellular carcinoma.

Thymus-derived cells (T cells) were stained by the immunofluorescent technique, and found to be predominate around the cancer cell nests, in the interstitium, and in the lumen of the sinusoid of the liver bearing hepatocellular carcinoma (hepatoma). The marked T cell predominance in the liver obtained at autopsy in 19 of 13 patients with hepatoma indicates that specific T cell-mediated immunity may be maintained even in the terminal stage of cancer in these patients.

Carcinoma, Hepatocellular↗
PubMed1981

Introduction of bacteriophage Mu into bacteria of various genera and intergeneric gene transfer by RP4::Mu.

The host range of coliphage Mu was greatly expanded to various genera of gram-negative bacteria by using the hybrid plasmic RP4::Mu cts, which is temperature sensitive and which confers resistance to ampicillin, kanamycin, and tetracycline. These drug resistance genes were transferred from Escherichia coli to members of the general Klebsiella, Enterobacter, Citrobacter, Salmonella, Proteus, Erwinia, Serratia, Alcaligenes, Agrobacterium, Rhizobium, Pseudomonas, Acetobacter, and Bacillus. Mu phage was produced by thermal induction from the lysogens of all these drug-resistant bacteria except Bacillus. Mu phage and RP4 or the RP4::Mu plasmid were used to create intergeneric recombinant strains by transfer of some genes, including the arylsulfatase gene, between Klebsiella aerogenes and E. coli. Thus, genetic analysis and intergeneric gene transfer are possible in these RP4::Mu-sensitive bacteria.

Anti-Bacterial Agents↗
PubMed1981

Regulation of derepressed synthesis of arylsulfatase by tyramine oxidase in Salmonella typhimurium.

The participation of tyramine oxidase in the regulation of arylsulfatase synthesis in Salmonella typhimurium was studied. Arylsulfatase synthesis was repressed by inorganic sulfate, cysteine, methionine, or taurine. This repression was relieved by tyramine, octopamine, or dopamine, which induced tyramine oxidase synthesis, although the level of arylsulfatase activity was very low. The induction of tyramine oxidase and derepression of arylsulfatase by tyramine were strongly inhibited by glucose and ammonium chloride, and the repression of both enzymes was relieved by use of xylose as a carbon source after consumption of glucose or by use of tyramine as the sole source of nitrogen, irrespective of the carbon source used. The initial rates of tyramine uptake by cells grown with glucose and xylose were similar. Results with tyramine oxidase-constitutive mutants showed that constitutive expression of the tyramine oxidase gene resulted in derepression of arylsulfatase synthesis in the absence of tyramine. Thus, catabolite and ammonium repressions of arylsulfatase synthesis and the induction of the enzyme by tyramine seem to reflect the levels of tyramine oxidase synthesis. These results in S. typhimurium support our previous finding that the specific regulation system of arylsulfatase synthesis by tyramine oxidase is conserved in enteric bacteria.

Ammonia↗
PubMed1981

Initiation and propagation of canine renal pelvic peristalsis.

A new in vitro method was employed which enabled detailed examination of the initiation and propagation of the peristaltic contraction of the renal pelvis and ureter. Both the kidney and its attached ureter were carefully removed and the renal parenchyma concealing the renal pelvis and calyces removed under the dissection microscope. At the pelvicalyceal border, ripple-like peristaltic contraction of a constant frequency were observed. At the same time, electromyograms with a slow rising phase were recorded at constant intervals from the pelvicalyceal border, leading us to deduce that these might represent pacemaker potentials. The discharge interval of electromyograms recorded at both the center of the pelvis and the pelviureteric junction were found to be a multiple of the 'pacemaker' interval. Electrical activity (peristalsis) arising from the pacemaker might be blocked at only the center of the pelvis but also at the pelviureteric junction.

Animals↗
PubMed1981

Regional arterial infusion of an anticancer drug combined with direct hemoperfusion.

The capacity of activated charcoal to adsorb anticancer drugs, Mitomycin C, Adriamycin and Bleomycin was examined in vitro in a closed circuit through a perfuser containing uncoated activated charcoal. Samples were obtained from the inlet and outlet of the perfuser every 30 min. As in vivo experiments, regional arterial infusion of anticancer drugs combined with direct hemoperfusion was performed on dogs. In 20 male mongrel dogs a polyethylene catheter was indwelt in the internal iliac artery and anticancer drugs were infused through the catheter for 1 hr. By using the femoral vessels for the blood access, direct hemoperfusion was performed for 3 hr. The adsorptive capacity of activated charcoal was high in both in vitro and in vivo experiments. These results indicate that regional arterial infusion of anticancer drugs combined with direct hemoperfusion would be useful for preventing their toxicity.

Adsorption↗
PubMed1981

Plasma beta-thromboglobulin and platelet factor 4 in patients with chronic renal failure and effect of hemodialysis.

Significantly increased levels of plasma beta-thromboglobulin (beta-TG) (76.8 +/- 25.5 ng/ml, p less than 0.01) were observed in 24 patients with chronic renal failure (blood urea nitrogen (BUN) greater than 20 mg/100 ml), as compared with normal subjects (13.2 +/- 5.6 ng/ml). The increase in beta-TG was highly correlated with BUN (r = 0.651, p less than 0.01), creatinine (r = 0.778, p less than 0.01) and creatinine clearance ( t = -0.723, p less than 0.01). Plasma platelet factor 4 (PF4) and normal 5.0 +/- 2.0 ng/ml) also increased significantly to 8.5 +/- 3.4 ng/ml (p less than 0.01). However, statistical correlation between beta-TG and PF4 was not found in these patients. The reason is thought to be due to differences in molecular weight (PF4 8,000 MW; beta-TG 36,000 MW) and half-life time (PF4 30 min; beta-TG 100 min), and due to the difficulty in calculating statistically the correlation because of the narrow distribution of PF4 levels. The high levels of beta-TG (89.4 +/- 3.4 ng/ml) showed a further increase (109.4 +/- 5.8 ng/100 ml, p less than 0.01) after dialysis. This is thought to be due to hemoconcentration, because other blood factors such as RBC, WBC, platelets, fibrinogen, etc were elevated by about 20% during hemodialysis and because no adhesion of platelets to the cellulose membrane did occur. The increase in PF4 levels at 15 min (55.2 +/- 19.6 ng/ml, p less than 0.01) and 1 hr (23.7 +/- 8.4 ng/ml, p less than 0.01) of hemodialysis from the level before it (7.7 +/- 1.3 ng/ml) is thought to be caused the effect of heparin infusion. The change in PF4 was not accompanied by the change in beta-TG. During hemodialysis the decrease of other platelet functions such as adhesiveness, aggregation induced by ADP, collagen and PF3 remained unchanged.

Adult↗