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Biomedical subjects

T Amano

Publications and source records attributed to T Amano.

At least 235 records · Page 13Linked to original sources
PubMed1992

Regulation of nerve growth factor and nerve growth factor receptor production by NMDA in C6 glioma cells.

The synthesis of nerve growth factor (NGF) and nerve growth factor receptor (NGFR) were studied in a C6 glioma cell line by Northern blot hybridization. In response to a glutamate agonist N-methyl-D-aspartic acid (NMDA), NGF mRNA increased by up to 2-fold after 4-12 h of culture. The non-NMDA receptor agonists, quisqualate and kainate, did not induce any increase of NGF mRNA, and kainate actually produced a decrease. The increase in NGF mRNA in response to NMDA was dose-dependent at 1, 5 and 10 microM. NGF receptor (NGFR) mRNA showed changes in expression which were similar to those for NGF mRNA, but were less marked. The specific glutamate antagonist 2-aminophosphonovaleric acid (APV) blocked the increase of NGF mRNA produced by NMDA. In the absence of Ca2+, an increase of NGF mRNA was still observed but in the presence of 1 mM ethylglycol-bis-(beta-aminoethyl ether) N,N'-tetraacetic acid (EGTA), NGF mRNA production abolished. The mechanism producing an increase in NGF mRNA by NMDA may be mediated by cyclic AMP since intracellular cyclic AMP and NGF mRNA levels both increased following treatment with NMDA or dibutyryl cyclic AMP.

2-Amino-5-phosphonovalerate↗
PubMed1992

Production and secretion of nerve growth factor by clonal striated muscle cell line, G8-1.

Two specific methods, Northern blot analysis using a 50 nucleotides probe to the conserved region of the nerve growth factor (NGF) gene, and enzyme immunoassay using a monoclonal biotinylated rat anti-NGF IgG-avidin conjugated peroxidase system, were used to demonstrate the production and secretion of NGF by mouse striated muscle cell line G8-1. Calcium ionophore, A23187 (0.1-1 microM), forskolin (0.1-100 microM) and dibutyryl cyclic AMP (0.1-10 mM) strongly decreased the secretion of ir-NGF. The level of NGF mRNA was decreased by veratridine, A23187, forskolin and cyclic AMP but not by cyclic GMP. Consequently, we conclude that the secretion of NGF molecules paralleled the changes of NGF mRNA levels in the cells induced by all agents tested. Carmamylcholine also decreased the level of NGF mRNA. Immunoblot analysis suggested that denatured ir-NGF molecules exist in a higher molecular weight form (22 KDa) than those of mouse submaxillary gland (13 KDa). Both Ca(2+)- and cAMP mediated mechanisms contribute to the decreased production of NGF mRNA in the cells and the consequent inhibition of secretion of NGF molecules. Finally, molecular cloning of NGF of G8-1 cells was conducted and confirmed the structure of the gene that consists of 1, 3, and 4 exons deleting exon 2. Thus, G8-1 NGF is derived from transcript B.

Amino Acid Sequence↗
PubMed1992

[Isolation of vero-cytotoxin-producing Escherichia coli from cattle and serotyping and toxin-typing of the isolated strains].

Two hundred and sixty-six piglets with diarrhea (from 4 farms), 73 healthy pregnant pig (from 2 farms), 27 calves with diarrhea (from 9 farms) and 47 healthy milk cows (from 1 farm) were examined for Vero-cytotoxin-producing Escherichia coli (VTEC), and 52, 11, 15 and 67 strains of VTEC were isolated from 17 piglets, 11 pregnant pigs, 6 calves and 23 milk cows, respectively. All VTEC strains from the piglets produced only VT2vp, while the strains from the healthy pigs did not produce VT2vp, but did VT1 and/or VT2. Most VTEC strains from calves and cows produced VT2vhb and some produced VT2 and VT1. Serotyping of the isolated strains showed that many strains from the piglets belonged either O139:H1, O141:H4 or O141:HUT, but the strains from the pigs were either R-form or O-untypable. Many strains from the calves and cows were serotyped into O116 or O113, but there were several R-form and O-untypable. From these results, it is suggested that VTEC strains, especially from the pregnant pigs, calves with diarrhea and healthy milk cows, which produced the same type of Verotoxins to that produced by human isolates, may become sources of human infections.

Animals↗
PubMed1992

Growth inhibition of RPMI 8226 human myeloma cells by peripheral blood lymphocytes.

To clarify the components of cellular immunity responsible for defense against the clonal development of myeloma cells, we tested the capacity of human peripheral blood lymphocytes (PBLs) to inhibit the growth of 3 human myeloma cell lines (RPMI 8226, OPM-1, and OPM-2). RPMI 8226 was found to be sensitive to PBLs, showing almost complete growth arrest when cultured with PBLs for 72 h. Inhibition of the growth of RPMI 8226 cells required direct cell-to-cell contact but not presensitization of the PBLs to the target cells, and did not depend on the generation of soluble factors. CD3+, CD4-, CD8- and CD16- cells were found to be the major subset contributing to inhibition of the growth of RPMI 8226 cells, and this growth inhibition was cytostatic rather than cytotoxic. These characteristics distinguished it from growth inhibition mediated by the natural killer system. Impaired PBL-mediated growth inhibition of RPMI 8226 cells was found in patients with various hematologic diseases, including myeloma. It therefore appears that the CD3+, CD4-, CD8- and CD16- cell subset might be involved in tumor immunity in myeloma.

Antibodies, Monoclonal↗
PubMed1992

Enhanced expression of complement regulatory proteins on thyroid epithelial cells of Graves' disease.

Cytotoxic anti-thyroid microsomal autoantibodies are highly prevalent in sera of patients with Graves' disease, but in Graves' disease thyroid tissues rarely show destructive changes. We postulated that this might be due to membrane-associated complement regulatory proteins which protect target cells from injury by complement activation. We, therefore, investigated the expression of membrane attack complex inhibitory factor (MACIF) and decay accelerating factor (DAF) in the thyroid tissues from patients with Graves' disease, Hashimoto's thyroiditis, thyroid adenocarcinoma and normal human thyroid tissues. We found a high level of expression of MACIF and DAF in Graves' thyroid tissues. Using the membrane immunofluorescence and cell-ELISA techniques, we also investigated the factors which enhanced the MACIF and DAF expression in cultured thyroid cells. Thyroid stimulating hormone, phorbol 12, 13-dibutyrate and thyroid stimulating autoantibody enhanced the MACIF and DAF expression. These findings suggest that the membrane complement regulatory proteins increase in response to the thyroid stimulating factors such as thyroid stimulating autoantibody in Graves' disease and that this increase then protects the cells from damage due to complement activation by thyroid autoantibodies.

Antigens, CD↗
PubMed1992

[A case of retroperitoneal Castleman's disease associated with bladder tumor and a review of 59 cases in Japan].

We present a case of retroperitoneal Castleman's disease associated with bladder tumor. The patient was a 62-year-old man, who underwent partial cystectomy under a diagnosis of bladder tumor in 1989. Subsequently, recurrent bladder tumor was detected and he consulted the outpatient clinic at our University Hospital in November, 1990, at which time computerized tomography (CT) revealed a retroperitoneal tumor. From February, 1991 four courses of combined chemotherapy (methotrexate, vinblastine, pirarubicin, cisplatin) were administered for the tumor. The tumor reduction rate after the chemotherapy was 60% on CT, and retroperitoneal lymph node dissection and left nephroureterectomy were performed in July, 1991. Histological examination revealed Castleman's disease, hyaline-vascular type. Fifty-nine reported cases of retroperitoneal Castleman's disease in Japan are reviewed.

Castleman Disease↗
PubMed1992

[A case of drug-induced esophageal ulcer developed at the esophageal constriction due to the right aortic arch].

A 26-year-old male has a tooth extracted at a dental surgery, and was given 40 mg Froben, as an anti-inflammatory analgesic agent, and ingested one tablet without water. After 2 days, anterior chest pain occurred. Esophagography and endoscopy were performed and multiple esophageal ulcers were confirmed. Esophagography revealed an esophageal stenosis which was considered to be caused by the extramural compression on the oral side of the ulcers. In the chest roentogenography and CT scanning, the right aortic arch was observed. This case was diagnosed as having drug-induced esophageal ulcer developed at the esophageal constriction due to the vascular ring.

Adult↗
PubMed1992

[Renal pelvic extravasation of urine associated with ureteral stones: report of two cases].

We report a case of spontaneous rupture of the renal pelvis and a case of spontaneous peripelvic extravasation, which were associated with ureteral stones. Case 1 was in a 73-year-old man with complaint of left flank pain. Excretory urograms showed left spontaneous rupture of the renal pelvis associated with left ureteral stone. Double-J ureteral stent was placed immediately and transurethral ureterolithotripsy (TUL) was performed after disappearance of extravasation. Case 2 was in a 34-year-old woman with complaint of left flank pain. Excretory urograms showed left ureteral stone and spontaneous peripelvic extravasation. The stone passed spontaneously and the extravasation disappeared with conservative therapy.

Adult↗
PubMed1992

[A case of acute extrinsic malfunction of prosthetic valve due to suture tag causing incomplete closure of the disc].

A 56-year-old woman who had suffered from both aortic and mitral valve stenosis and regurgitation was treated by replacement of valves with 23 mm and 27 mm Björk-Shiley valves respectively. After weaning from cardiopulmonary bypass, the arterial systolic pressure rose to 100 mmHg but the diastolic pressure fell to 40 to 50 mmHg. Studies including transesophageal echocardiogram and fluoroscopy during operation revealed the valves functioning normally. Because low diastolic pressure and low cardiac output continued during postoperative period, fluoroscopy was carried out again. It showed incomplete diastolic closure of the disc of the prosthetic aortic valve. The emergency operation was performed. At reoperation, it was found that one of the end of suture knots located between the valve ring and the disc prevented the occluder from seating completely and caused aortic regurgitation. The suture end was cut shorter and the prosthesis within the sewing ring was rotated so that the occluder was kept away from the suture end.

Aortic Valve↗
PubMed1991

Production of nerve growth factor in rat skeletal muscle.

Production of the nerve growth factor (NGF) was confirmed by Northern blot hybridization using a specific probe of synthetic cDNA. In normal rat skeletal muscle, this probe clearly showed a band equivalent to 1.3 kilobases (kb) of messenger RNA (mRNA) of NGF of male mouse submaxillary gland. By denervation, the density of the bands derived from muscles increased by a factor of more than 3 at 4 and 6 days later compared to the control. The synthesis of mRNA of NGF in muscle was also confirmed following tetrodotoxin (TTX) blockade of sciatic nerve without denervation.

Animals↗
PubMed1991

Phase I study and pharmacological analysis of cis-diammine(glycolato)platinum (254-S; NSC 375101D) administered by 5-day continuous intravenous infusion.

A phase I study of cis-diammine(glycolato)platinum (254-S; NSC 375101D) was conducted in 15 patients with refractory or relapsing malignancy by 5-day continuous i.v. infusion. Three to 5 patients per dose were given 50, 75, 87.5, or 100 mg/m2/120 h (10-20 mg/m2 daily for 5 days). Toxicity evaluation and pharmacokinetic analysis were performed in 15 and 14 patients, respectively. Thrombocytopenia and neutropenia were the dose-limiting toxicities at the maximum tolerated dose of 87.5 mg/m2/120 h (17.5 mg/m2/day); however, nonhematological toxicities including renal toxicity, nausea and vomiting, and peripheral neuropathy were mild and well tolerated. The nadir of platelets and neutrophils was observed 4 and 5 weeks, respectively, after the initiation of drug infusion. Plasma and urine samples were obtained during and after infusion for quantification by atomic absorption spectrophotometry of total and free platinum levels derived from 254-S. The maximum level of total platinum was obtained after 120 h of infusion, whereas the steady state concentration of free platinum in the patients given 75 mg/m2 or more was over 0.1 microgram/ml. Free platinum levels declined monophasically, with half-lives of 0.65-2.56 h/100 mg/m2 dose. The mean area under the concentration versus time curve (AUC) in the patients treated with 75 mg/m2 was 1069 micrograms/ml, which was similar to that obtained in the patients receiving 100 mg/m2 of 254-S by i.v. drip infusion over 30 min. There was a direct correlation between the dose administered and the AUC of platinum (R = 0.757, P = 0.002) or the steady state plasma concentration of free platinum (R = 0.763, P = 0.002). The percentage of platinum excreted in urine 144 h after the initiation of infusion ranged from 73.1 to 100% for each dose level. No significant relationship was established between creatinine clearance in patients before treatment and the AUC or steady state concentration of free platinum. The plasma platinum AUC showed a linear correlation with the percentage of change in leukocytes [formula: see text] (R = 0.736, P = 0.003). In conclusion, the recommended phase II dose for a continuous infusion of 254-S is 75.5 mg/m2/120 h every 6 hours.

Adult↗
PubMed1991

Integral laser photodynamic treatment of refractory multifocal bladder tumors.

Integral photodynamic therapy with hematoporphyrin derivative was performed on 35 patients who had resistant transitional cell carcinoma of the bladder, mainly carcinoma in situ. The light source was an argon ion pumped dye laser (wavelength 630 nm.) using rhodamine B. Two types of laser light scattering diffuser developed at our department were used: a motor driven laser light scattering diffuser with computer regulation, and an endoscope modified light scattering diffuser tipped with a small quartz bulb containing a lipid nutritious solution as the scattering medium. The total energy density used was 10 to 30 J./cm.2. Of the 35 patients 24 (68.6%) achieved a complete response and 5 (14.3%) a partial response at 3 months. In 10 of the 24 patients there was no recurrence with an average tumor-free interval of 20.9 +/- 16.7 months, ranging from 5 to 60 months. Bladder capacity was decreased to approximately 150 ml. for 3 months after the integral photodynamic therapy without any evidence of hydronephrosis on excretory urograms, except for 2 patients who had a contracted bladder before photodynamic therapy. Integral photodynamic therapy may prove to be useful for the treatment of carcinoma in situ of the bladder.

Adult↗
PubMed1991

Locus coeruleus stimulation exerts different influences on the dynamic changes of cerebral pial and intraparenchymal vessels.

The present experimental study was undertaken to investigate the effects of locus coeruleus stimulation on the dynamic changes of intraparenchymal vessels and pial vessels. Twelve cats were anaesthetized with alpha-chloralose and urethane. For stimulation of the locus coeruleus, a concentric stainless-steel needle electrode was inserted stereotaxically. During the stimulation, volumetric changes of the intraparenchymal vessels were monitored by a photoelectric method for estimating the cerebral blood volume (CBV) (6 cats), and the diameters of pial arteries were measured continuously using a video camera system (6 cats). The CBV followed a decreasing course during the stimulation of the locus coeruleus. The decrease in CBV from the control value (6.3 vol%) was 0.14 +/- 0.04 vol% at 80 s (p less than 0.05), 0.15 +/- 0.05 vol% at 100 s (p less than 0.05), and 0.15 +/- 0.03 vol% at 120 s (p less than 0.01). After cessation of the stimulation, CBV showed a gradual recovery. On the other hand, the diameters of the pial arteries did not change during or after the stimulation of the locus coeruleus. The above results suggest that the locus coeruleus has a vasoconstrictive effect on the intraparenchymal vessels, although it exerts no apparent influence on the pial arteries.

Animals↗
PubMed1991

[Follow-up study in a case of traumatic epilepsy with increased accumulation of 123I-N-isopropyl-p-iodoamphetamine].

Recent studies suggested the potential use of 123I-N-isopropyl-p-iodoamphetamine (IMP) for the assessment of pathophysiology of epilepsy. We studied a case of epilepsy with increased accumulation of IMP. Brain SPECT scan of IMP was performed in a case of 31-year-old male with traumatic epilepsy. Increased accumulation of IMP was observed in the left temporal area on both early (20 min after injection) and delayed (3 hr) images of studied 6 weeks after the head trauma. X-CT did not show any abnormalities. The accumulation of IMP decreased as the symptom of the patient improved. The SPECT study performed 3 months after the accident showed slightly decreased uptake in the left temporal area on the early image with homogeneous uptake in the delayed image. These findings suggested the altered retention mechanism of IMP in this case.

Adult↗