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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 703 records · Page 39Linked to original sources
PubMed1986

Bone in the marmoset: a resemblance to vitamin D-dependent rickets, type II.

The common marmoset, a New World monkey, requires a large amount of vitamin D3 to maintain its normal growth. This monkey is reported to have an end-organ resistance to 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3). In this study, the bone morphology of marmosets fed a high vitamin D3 diet (intake of vitamin D3, 110 IU/day/100 g of body weight) was compared by X-ray and histological examinations with that of rhesus monkeys (Old World monkey) fed a normal diet (intake of vitamin D3, 5 IU/day/100 g of body weight). Three of 20 marmosets were found by X-ray examination to have osteomalacic changes in their bones despite the high daily intake of vitamin D3, whereas none of the 5 rhesus monkeys showed any signs of osteomalacia. Osteomalacic marmosets had distinct increases in osteoid surface, relative osteoid volume, and active osteoclastic bone resorption, whereas non-osteomalacic marmosets had no increase in osteoid tissues in their bones. None of the marmosets, either osteomalacic or non-osteomalacic, was hypercalcemic despite the extremely high circulating levels of 1 alpha,25(OH)2D3. However, the serum 25-hydroxyvitamin D3 (25OHD3) and 24R,25-dihydroxyvitamin D3 (24R,25(OH)2D3) levels were significantly lower in the osteomalacic than in the non-osteomalacic marmosets. These results suggest that the marmoset is likely to exhibit osteomalacic bone changes despite the high daily intake of vitamin D3. These changes resemble those in vitamin D-dependent rickets, type II.

24,25-Dihydroxyvitamin D 3↗
PubMed1986

Comparison of the mechanisms of bone resorption induced by 1 alpha,25-dihydroxyvitamin D3 and lipopolysaccharides.

The mechanisms of increase in bone resorption induced by 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] and bacterial lipopolysaccharides (LPS) were compared in an in vitro dead bone assay and a living bone assay. 1 alpha,25(OH)2D3 at concentrations of 0.05-5 ng/ml dose-dependently enhanced the ability of alveolar macrophages to release 45Ca from prelabeled dead bone particles (dead bone assay). In addition, the vitamin promoted fusion of the macrophages to form multinucleated cells and also enhanced glucose consumption, a marker of activation of macrophages. LPS at 0.05-5 micrograms/ml similarly enhanced the release of 45Ca from the dead bone particles and glucose consumption by alveolar macrophages, but it did not induce fusion of the cells at any concentration. Both 1 alpha,25(OH)2D3 and LPS dose-dependently stimulated the release of 45Ca from fetal mouse calvaria prelabeled with 45Ca (living bone assay). Compared to control bone, there were several times as many osteoclasts per given length of trabecular bone surface in calvaria treated for 5 days with either 5 ng/ml of 1 alpha,25(OH)2D3 or 5 micrograms/ml of LPS. Indomethacin (10(-5) M) completely inhibited the LPD-induced increase of osteoclasts, but not the 1 alpha,25(OH)2D3-induced increase. These results suggest that 1 alpha,25(OH)2D3 and LPS similarly stimulate bone resorption by activating macrophages as well as by promoting fusion of precursor cells to form multinucleated cells. 1 alpha,25(OH)2D3 induced formation of multinucleated cells with bone-resorbing activity directly, whereas LPS appeared to induce multinucleated cells through prostaglandin synthesis by some other types of cells present in living bone tissues.

Animals↗
PubMed1986

Light-induced potential and current across a large bacteriorhodopsin-asolectin planar membrane stabilized on a polyacrylamide gel surface.

A phospholipid bilayer membrane was spread from an organic solvent solution between a polyacrylamide gel surface and an aqueous buffer solution. The membrane was quite similar to the conventional black lipid membrane, but was of a large size and was stable since it was supported on the gel surface. Bacteriorhodopsin, impregnated into the membrane, generated membrane potential and current upon illumination. The induced current was large, and this was attributed to the large area of the present membrane. Remarkable responses of the light-induced potential and current were also observed with a thick layer of organic solvent containing phospholipids. The effects of applied membrane potential, carbonylcyanide-m-chlorophenyl hydrazone (CCCP) and gramicidin were examined on these photoresponses. Steady-state current, which is due to protons flowing through the membrane, was enormously enhanced by applying membrane potential opposite to the photopotential or by adding gramicidin to the membrane-forming solution.

Acrylic Resins↗
PubMed1986

Does 'extended' pelvic lymphadenectomy truly contribute to the management of bladder carcinoma?

During a 3-year period, 41 patients with primary bladder carcinoma were treated with cystectomy along with pelvic lymphadenectomy. Although lymphadenectomy was useful for more accurate staging in patients with T2 or more invasive disease, it contributed little to the surgical curability of the disease, irrespective of extensive nodal dissection in the pelvis. Based on the characteristic lymphatic spread of the disease, limited dissection to the regional nodal area seemed to be satisfactory in the surgical management of bladder carcinoma.

Follow-Up Studies↗
PubMed1986

Serum Erythropoietin levels and inhibitors of erythropoiesis in patients with chronic renal failure.

The role of various factors in erythropoiesis was studied in 13 predialysis patients and 41 hemodialysis patients. Serum erythropoietin (ESF) was measured by the fetal mouse liver cell bioassay in vitro. The effect of uremic sera on heme synthesis and erythroid progenitor cell (CFU-E) formation was examined using normal human bone marrow cultures. Serum ESF levels in both predialysis (99.9 +/- 45.0 mU/ml) and dialysis (141.2 +/- 109.7 mU/ml) patients were significantly higher than those in normal controls (42.0 +/- 25.8 mU/ml), although the titers were not sufficiently increased to correct the anemia. Serum ESF concentrations did not correlate with hemoglobin level or inhibition of both heme synthesis and CFU-E formation. Bone marrow CFU-Es in uremic patients were normal in the number, the responsiveness to ESF and the percentage in S-phase. Significant decrease in heme synthesis was observed in dialysis patients. The degree of inhibition of CFU-E formation showed a relationship to hemoglobin levels in uremic patients. By the CFU-E formation assay, the difference in inhibitory effects of the sera obtained from dialysis patients immediately before and after a hemodialysis was significant only under a low ESF concentration (0.125 U/ml) but not under a high concentration (1.0 U/ml). In conclusion, inhibition of heme synthesis and CFU-E formation, in addition to inadequate ESF production, plays an important role in renal anemia.

Adult↗
PubMed1986

Delayed inactivation of Citrobacter freundii cephalosporinase by 6 beta-[3-(2-chlorophenyl)-5-methyl-4-isoxazolyl]penicillin sulfone.

When Citrobacter freundii cephalosporinase was incubated with 6 beta-[3-(2-chlorophenyl)-5-methyl-4-isoxazolyl]penicillin sulfone (cloxacillin sulfone) in phosphate buffer, the enzyme was suddenly inactivated just after the completion of enzymatic degradation of the cloxacillin sulfone. Such delayed inactivation was due to a secondary inhibitor formed from cloxacillin sulfone during the incubation period. The inactivation was delayed due to the protection of the enzyme by cloxacillin sulfone from the attack of the secondary inhibitor. Phosphate anions were essential for the formation of the secondary inhibitor. However, once the secondary inhibitor was formed, the inactivation occurred in the absence of phosphate anions although the degree of the inactivation depended on the length of the preincubation period with phosphate anions. The main species (more than 80%) of the inactivated enzyme was detected as a single protein band with a slightly lower pI value than that of the native enzyme on isoelectric focusing on a plate.

Buffers↗
PubMed1986

[Huge Virchow's metastasis in gastric cancer made resectable by hyperthermochemoradiotherapy].

A 75-year-old woman who had undergone gastrectomy for gastric cancer at the age of 61 developed a huge left supraclavicular tumor (15 X 10 X 10 cm) suspected of being Virchow's node. She was treated with hyperthermochemoradiotherapy (HCT-therapy). After 10 sessions of radiofrequency hyperthermia by a Thermotron RF8, irradiation with 52.8 Gy of 60Co and injection of 8 mg of MMC, the tumor mass decreased by 77% on CT. The histologically resected specimen revealed coagulation necrosis in almost all areas. This case, which was considered HCR-therapy-effective, was estimated as Grade 3 according to The General Rules for the Gastric Cancer Study (The 11th edition.)

Adenocarcinoma↗
PubMed1986

Surface marker expression of human B-cell lymphomas.

We have generated a battery of monoclonal antibodies (MAbs) that distinguish different antigen molecules present in human B cells. Two antigen systems, termed L26 and L27, respectively, were expressed in most surface immunoglobulin-positive B cells and thus showed pan-B cell specificity. Two other antigens (L22 and L30) appeared to be expressed mainly on small resting B cells but not on large activated B cells. In contrast with L22 and L30, L29 and L4, the latter of which corresponds to OKT10, were not or little expressed on resting B cells, but were found on these B cells after activation either in-vivo or in-vitro with staphylococcal protein-A (SAC) plus interleukin-2 (IL-2) or with pokeweed mitogen (PWM). We also produced MAb (L10) that detected IL-2 receptors (IL-2R) consistently expressed on in-vitro activated B cells as described above. In contrast with L4, L10 and L29, L30 was lost from in-vitro-activated B cells, following the appearance of either L10 or L29 on these in-vitro-activated B cells. Then, we analyzed antigen profiles of B cell tumors using these MAbs as described above. Common acute lymphatic leukemia (CALL) expressed L4 and L30. B cell type chronic leukemia (B-CLL) and hairy cell leukemia (HCL) possessed most of the B cell antigens as described herein, and furthermore, HCL expressed IL-2R as detected by L10 MAb. In the case of B cell lymphomas, they were phenotypically divided into two groups, corresponding to either early or late activated B cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1986

[Two cases of carcinoid tumor of the stomach and a collective review of the Japanese literature].

We report two cases of carcinoid tumor of the stomach together with a collective review of the Japanese literature. Case 1 was preoperatively diagnosed as carcinoid, and the lesion, measuring 10 X 7 mm, and located in the body of the stomach, had no metastases. Case 2 was preoperatively diagnosed as gastric cancer and was recognized as a submucosal tumor measuring 5.8 X 4.7 cm in the antrum of the stomach. There were metastases to the brain and the skin, and the patient died on the 50th day after the operation. From a collective review of previous cases, it was ascertained that small carcinoid tumors sometimes had metastases. For this reason, we feel gastrectomy should be performed together with local lymph node resection.

Carcinoid Tumor↗