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Biomedical subjects

Y Nagata

Publications and source records attributed to Y Nagata.

At least 307 records · Page 17Linked to original sources
PubMed1995

Changes of bone mineral density in pregnant and postpartum women.

OBJECTIVE: To explore the effects of pregnancy and postpartal lactation on bone mineral density (BMD). METHODS: In this study, the BMD of 22 pregnant women in a longitudinal study, and of 75 pregnant and 111 puerperant women in a cross-sectional study was estimated at the distal radius of the forearm by dual energy X-ray absorptiometry. BMD was measured on 8 separate occasions from the first trimester of pregnancy to 24 months' postpartum. RESULTS: In none of 22 pregnant women was there any noticeable change in BMD during pregnancy. Whereas no significant change in BMD occurred during the 12-month postpartum period in 11 non-lactating women, 11 women who breastfed had a significant decrease in BMD at 1, 3, and 6 months' postpartum, with all of them showing a further decrease in BMD at 12 months' postpartum. The BMD of the radius was significantly lower in the breast-feeders than in the formula-feeders at all postpartal times of evaluation except at 24 months' postpartum. CONCLUSION: It can be recommended that lactating women receive appropriate treatments for saving BMD during lactation.

Adult↗
PubMed1995

Effect of dietary antioxidants on the susceptibility to hepatic microsomal lipid peroxidation in the rat.

The inhibitory effect of probucol on ferrous-iron-induced microsomal lipid peroxidation was compared to that of alpha-tocopherol and butylated hydroxytoluene (BHT). Male Wistar rats were fed with diets containing 1% probucol, 0.2% BHT or 0.1% alpha-tocopherol for 30 days. There were no effects of dietary antioxidants on growth parameters, although liver weight was significantly higher in the BHT-fed rats. Probucol reduced serum levels of total and free cholesterol, while BHT feeding increased the concentrations of serum thiobarbituric-acid-reactive substances, HDL cholesterol and hepatic phospholipid. alpha-Tocopherol had no effect on these parameters. Incorporation of both, probucol and alpha-tocopherol, decreased the susceptibility of microsomes to lipid peroxidation in vitro, while BHT incorporation increased hepatic microsomal lipid peroxidation. These results suggest the possible usefulness of probucol for treatment of both hypercholesterolemia and elevated hepatic microsomal lipid peroxidation, while alpha-tocopherol decreases only an elevated lipid peroxidation. BHT works as a prooxidant.

Animals↗
PubMed1995

Pseudomonas fluorescens KKL101, a benzoic acid degrader in a mixed culture that degrades biphenyl and polychlorinated biphenyls.

A mixed culture we had isolated, which degrades biphenyl/polychlorinated biphenyls, is composed of two strains, Pseudomonas fluorescens KKL101 and Pseudomonas sp. strain KKS102. KKS102 produces benzoic acid as a dead-end metabolite in the degradation of biphenyl. In this study we showed that KKL101 grew on benzoic acid as a sole source of carbon. This indicated a role of KKS102 in the growth of KKL101 and KKL101 for the growth of KKS102 in the mixed culture.

Bacteriological Techniques↗
PubMed1995

Traumatic neuroma of the common hepatic duct after laparoscopic cholecystectomy.

Jaundice and stricture of the common hepatic duct were detected in a 53-yr-old woman 2 months after she had laparoscopic cholecystectomy for a gallstone. Then she underwent resection of the stricture part of the duct and hepaticojejunostomy which was effective. Pathological examination showed that traumatic neuroma, probably caused by bile leakage after cauterization, led to stricture of the common bile duct.

Bile Duct Neoplasms↗
PubMed1995

Clinical results of breast-conservation therapy using a CT simulator.

The CT simulator is a real-time, CT-linked, 3-D treatment planning system which consists of a CT scanner, a multi-image display, a treatment planning device with real-time visual optimization, and a laser beam projector. The clinical benefit of this system was evaluated in breast cancer patients undergoing breast-conserving therapy. Between December 1987 and March 1993, 244 breasts in 243 patients underwent breast-conserving therapy at Kyoto University Hospital. Clinically, there were 159 stage I and 85 stage II tumors. Pathological staging showed 216 stage I, 24 stage II, and 4 stage III tumors. All except 10 tumors were invasive ductal carcinomas. Eleven tumors were margin-positive by histopathological examinations. As surgical treatment, quadrantectomy or wide excision with complete axillary dissection was performed. Radiation therapy consisted of 50 Gy delivered to the whole breast by opposed tangential fields over 5 weeks using 60Co gamma rays. For patients with a positive margin, boost electron irradiation was given to a total of 10 Gy. We used the CT simulator for individualized optimization of the tangential fields. Prompt and accurate determination of the tangential portals was possible by using the simulator to determine various parameters, including the beam angle and head rotation angle. During follow-up for 2-66 months (median: 20 months), unrelated death occurred in 2 patients and distant metastases developed in 5 (bone 4, lung 1). However, neither local recurrence nor symptomatic radiation pneumonitis has since occurred. The cumulative survival rate and the disease-free survival rate at five years were 95.2% and 91.8%, respectively. The CT simulator appears to be a useful tool for individualized optimization of tangential irradiation fields in breast-conserving therapy.

Adult↗
PubMed1995

[Recent progress of thermoradiotherapy in cancer therapy].

The recent progress of thermoradiotherapy for cancer is reviewed. Several biological methods for increasing the effects of heat on tumors have been developed, and some of them are being clinically investigated. Physical progress includes two new heating devices developed in Japan. One is an ultrasound heating system and the other is an intracavitary RF heating applicator in which simultaneous intracavitary irradiation is possible. The negative results of RTOG trial in USA caused a great impact in clinical hyperthermia. Careful analysis of this trial, however, demonstrated the advantages of the use of hyperthermia for those cases in which ther was good quality assurance of hyperthermia. Recent results of ESHO trials in Europe clearly demonstrated the superiority of thermoradiotherapy over radiotherapy alone for several tumors. Various site-specific clinical trials are expected to clarify the indications of thermoradiotherapy in future.

Clinical Trials, Phase III as Topic↗
PubMed1995

[Prolonged muscle paralysis after long-term infusion of muscle relaxants and large doses of steroids].

We have recently encountered three patients who developed prolonged muscle paralysis after long-term infusion of muscle relaxants and administration of large doses of steroids. Among many factors implicated in the cause of this paralysis, steroids and muscle relaxants were suggested to be most likely causative agents. In order to avoid such muscle paralysis, we must be careful to limit the dose of relaxants as small as possible. For this purpose, monitoring of neuromuscular blockade is indispensable.

Female↗
PubMed1995

[Two cases of micrognathia caused by radiation therapy during infancy: an evaluation of their profilograms].

Two patients with micrognathia of the mandible caused by radiation therapy during infancy are reported herein. The first patient was a 25-year-old man with hemangioma of the tongue. He had previously received radiation therapy totaling 51 Gy at 1 and 2 years of age. The other patient was a 54-year-old woman who had received radiation therapy for an oral tumor during infancy. These two patients demonstrated micrognathia, and the former patient showed developmental anomaly of the teeth. In addition, the latter patient suffered from thyroid cancer at 45 years of age, and this was also thought to be radiation-related. Although reports of micrognathia caused by radiation are rare, such late effects should be taken into account when radiation therapy is planned for head and neck tumors in infants.

Adult↗
PubMed1995

Modulation of platelet activation in vitro by thrombopoietin.

Effect of human recombinant thrombopoietin (TPO) on platelet activation in vitro was studied. Although TPO itself did not cause platelet aggregation, it upregulated ADP-induced aggregation, especially the second wave of aggregation. This effect was dose-dependent for up to 5 ng/ml of TPO. When platelets were activated by epinephrine, collagen, or alpha-thrombin, similar effect was observed. However, TPO did not affect A23187- or PMA-induced aggregation, suggesting that TPO may have modulated the signal transduction pathway upstream of inositol 1,4,5-trisphosphate and diacylglycerol production. TPO also upregulated thrombin-induced alpha-granule secretion. To clarify the involvement of protein tyrosine phosphorylation, platelets were activated by TPO and/or suboptimal concentration of ADP, then tyrosine phosphorylation was detected by immunoblot analysis, using anti-phosphotyrosine monoclonal antibody. TPO by itself caused significant tyrosine phosphorylation of 146, 130, 122, 108, 97, 94, and 88 kDa proteins. Further, by using antibodies against signal transduction molecules for immunoprecipitation, we observed the significant tyrosine phosphorylation in Jak2 and Tyk2 molecules after TPO-stimulation. The results of the present experiment clearly indicate that TPO directly activated platelets and modulated intracellular signal transduction pathway.

Blood Proteins↗
PubMed1994

Preliminary Results of Quadrantectomy and Radiation Therapy for Breast Cancer.

Between November 1987 and December 1992, a total of 200 breast carcinomas in 199 patients were treated by definitive radiation therapy following quadrantectomy and level III axillary dissection. One patient with sumultaneous bilateral breast cancers was excluded and 198 patients with breast cancer were enrolled in this study. There were 9 Stage 0, 117 Stage I and 72 Stage II tumors by the UICC tumor classification system (1987). Histological examination revealed that 9 tumors were non-invasive carcinomas and 189 were invasive carcinomas. For radiation therapy, a total of 50 Gy was delivered to the ipsilateral breast using &sup60;Co gamma rays. In three cases with level III lymph node involvement, the ipsilateral supraclavicular and parasternal regions were also irradiated. Boost irradiation was given to 8 of 12 margin-positive patients, and 2 of 24 patients in whom tumor cells were present within 5 mm from the margin. We used a CT simulator for the treatment planning of radiation therapy in 196 tumors. During follow-up for 16-77 months (median: 35 months), 2 patients died of unrelated causes and 6 developed distant metastasis (4 to bone and 2 to lung). Local recurrence was noted in 1 patient. Acute reactions to radiation therapy included moist desquamation involving the tip of the breast and the axilla in 14 and 5 patients, respectively, as well as bright erythema in 7 patients. Late reactions included arm edema in 12 patients, patchy depigmentation at the tip of the breast in 5 patients, moderate telangiectasia in 1 patient, and symptomatic radiationpneumonitis in 1 patient. The actuarial overall survival, cause-specific survival, disease-free survival, and relapse-free survival rates at 5 years were 97.2%, 100%, 93.5%, and 93.0%, respectively. This excellent locoregional control, together with a highly acceptable toxicity strongly suggests the usefulness of quadrantectomy and radiation therapy for Japanese women with breast cancer. The possible indications include clinical Stage 0 and, I breast cancer, and clinical Stage II cancer in patients with relatively large breasts and with the primary tumor not located close to the nipple.

Journal Article↗
PubMed1994

Three-dimensional treatment planning for maxillary cancer using a CT simulator.

PURPOSE: The results of three-dimensional treatment planning using a computed tomography simulator were evaluated in patients with maxillary cancer. METHODS AND MATERIALS: Treatment planning was done in 25 patients using an x-ray simulator and plain x-ray films (1979-1982, group 1) in 34 patients using an x-ray simulator and computed tomography films (1983-1987, group 2), in 24 patients using a computed tomography simulator (1988-1992, group 3). The number of patients with Stage IV disease increased in the order of group 1 to group 3. RESULTS: The average radiation field was smallest in group 3 (66.5 cm2) followed by group 2 (67.4 cm2) and group 1 (72.9 cm2). A radiation dose of more than 30 Gy to the lens of the effected side was delivered to 13% of group 3, 44% of group 2, and 44% of group 1. The dose to the lens on the uneffected side was zero in 56% of group 1, 74% of group 2, and 96% of group 3. A long-term decrease in visual activity on the effected side occurred in 11% of group 3, 32% of group 2, and 44% of group 1. However, a significant increase in survival was only noted between groups 1 and 2, because the three population of patients were different. CONCLUSION: The three-dimensional treatment planning results in a better treatment than two-dimensional treatment planning as measured by complication rates and field sizes.

Aged↗
PubMed1994

High-performance liquid chromatographic determination of catecholamine metabolites and 5-hydroxyindoleacetic acid in human urine using a mixed-mode column and an eight-channel electrode electrochemical detector.

An HPLC system for the simultaneous determination of acidic catecholamine metabolites, related compounds and 5-hydroxyindoleacetic acid (5-HIAA) in human urine was developed. A mixed-mode (C18/anion-exchange) column with isocratic elution using citrate buffer and an eight-channel electrochemical detector were used. Vanilmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC), 4-hydroxy-3-methoxyphenyllactic acid (vanillactic acid, VLA), homovanillic acid (HVA), vanillic acid (VA) and 5-HIAA in urine were determined simultaneously. Detection limits and inter (n = 5) and intra-assay (n = 5) coefficients of variation were satisfactory. The mean of analytical recoveries (n = 3, +/- C.V. (%)) were between 97 +/- 3.2 (VMA) and 105 +/- 4.8 (VA). Correlations between the analytical results for VMA, HVA and 5-HIAA obtained by an established method and the present method were satisfactory. The mean +/- 2 S.D. of the excretion rates of VMA, DOPAC, VLA, HVA, 5-HIAA and VA in urine from healthy adult volunteers were 0.61-4.36, 0.13-1.02, 0-0.35, 0.67-6.55, 0.50-5.14 and 0-0.55 mg/g creatinine, respectively.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Identification of the bphA and bphB genes of Pseudomonas sp. strains KKS102 involved in degradation of biphenyl and polychlorinated biphenyls.

The nucleotide sequence of the upstream region of the bphC gene from Pseudomonas sp. strain KKS102 was determined. Four genes were found in this region. Deduced amino acid sequences of the first, second, third and fourth genes showed significant homology with a large subunit of iron-sulfur protein, a small subunit of iron-sulfur protein, ferredoxin and dihydrodiol dehydrogenase, respectively, from other bacteria which degrade biphenyl/polychlorinated biphenyls, toluene and benzene. E. coli, in which the four genes, bphC and the gene for ferredoxin reductase from benzene degrading bacterium were expressed, was able to produce meta-cleavage compounds from chlorinated biphenyls. These results show that these gene products are functional in both biphenyl and polychlorinated biphenyls degradation.

Alcohol Oxidoreductases↗
PubMed1994

The intercellular communication via nitric oxide and its regulation in coupling of cyclic GMP synthesis upon stimulation of muscarinic cholinergic receptors in rat superior cervical sympathetic ganglia.

Cyclic GMP (cGMP) production in rat superior cervical sympathetic ganglia (SCG) was markedly increased (ca. 7-9-fold) by the addition of either acetylcholine (ACh; 0.1 mM) or a muscarinic agonist, carbachol (Carb; 0.1 mM), in the presence of an inhibitor (3-isobutyl-1-methylxanthine) for cGMP hydrolytic enzyme during in vitro aerobic incubation at 37 degrees C for 5 min. The ACh-induced accumulation of cGMP in SCG was effectively blocked (-73%) by the further addition of atropine (10 microM), a muscarinic antagonist, whereas a nicotinic blocker, hexamethonium (10 microM) partially antagonized (-41%) this ACh stimulation. The inhibitory effect of hexamethonium on ACh-evoked ganglionic cGMP production was effectively augmented (-83%) by addition of NG-monomethyl-L-arginine (L-NMMA, 50 microM), a compound that inhibits nitric oxide (NO) synthesis from L-arginine. Comparable inhibition of cGMP formation was observed following application of L-NMMA to the SCG upon stimulation of Carb. In contrast, L-NMMA had no effect on the decreased level of ACh-evoked cGMP production caused by the muscarinic antagonist. The Carb-induced elevation of ganglionic cGMP synthesis was significantly reduced within 1 min of incubation in the medium containing hemoglobin (Hb; 20 microM), an agent that scavenges only the extracellular fraction of NO. Thereafter, the tissue cGMP formation attenuated to the control level by subsequent incubation for several minutes. Addition of protein kinase C (PKC) activator, 12-O-tetradecanoylphorbol 13-acetate (TPA; 1 microM) to the medium significantly decreased Carb-evoked cGMP synthesis (-61%) in SCG, whereas superoxide dismutase (SOD; 30 U/ml) only slightly suppressed the Carb stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

Activation of helix-loop-helix proteins Id1, Id2 and Id3 during neural differentiation.

Id is a nuclear factor containing a helix-loop-helix (HLH) motif. It has been reported that Id functions as an inhibitor of cell differentiation and its gene expression is down-regulated during cell differentiation. We have characterized three Id-related cDNAs, Id1, Id2 and Id3, isolated from nerve growth factor (NGF)-stimulated PC12 cells. Structural analysis revealed that all three Id's contain putative phosphorylation sites for cyclic AMP-dependent kinase, casein kinase II and protein kinase C near and inside the HLH motifs. In contradiction to the previous reports, Northern blot analysis revealed that NGF induces rapid and transient increase of all three Id gene transcriptions. Furthermore, in situ hybridization of rat embryo showed that all three Id genes are highly expressed in neural precursors rather than differentiated neural cells. These results indicate that Id family members may function as immediate-early gene products, and that the expression of the Id family may play an important role in the early stage of neural differentiation.

Amino Acid Sequence↗