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Biomedical subjects

T Tamura

Publications and source records attributed to T Tamura.

At least 775 records · Page 43Linked to original sources
PubMed1992

Estrogen as a growth factor to central nervous cells. Estrogen treatment promotes development of acetylcholinesterase-positive basal forebrain neurons transplanted in the anterior eye chamber.

In a previous report, we demonstrated in vivo ameliorating effects of conjugated estrogen in women suffering from senile dementia-Alzheimer's type. To investigate the effects of estrogen on the growth of cholinergic neurons, the present study was performed using rat cholinergic tissue implanted into the anterior chamber of the eye. Fetal diagonal band tissue containing cholinergic neurons was grafted into the anterior eye chamber of adult female rats that had either been treated or not with 2 mg estradiol valerate injected every 3 days after oophorectomy. Two and four weeks after transplantation, the axonal and/or dendritic growth of cholinergic neurons in the graft was studied using acetylcholinesterase histochemistry. At both times, acetylcholinesterase positive processes were densely distributed in the grafts of estradiol valerate treated rats, while in rats without estradiol valerate treatment acetylcholinesterase positive reaction was essentially localized only on the cell bodies. These findings were more obvious at 2 weeks after transplantation than at 4 weeks. These results suggest that estrogen acts on cholinergic neurons as a growth factor.

Acetylcholinesterase↗
PubMed1992

Deoxyribonucleic acid study on 2 XX male patients.

Two XX male patients were examined for the presence of 25 Y-specific loci using Southern blot analysis and polymerase chain reaction techniques. They were phenotypically normal male patients, although 1 had bilateral undescended testes and 1 had hypoplastic testes. The former patient had 10 of 11 loci on the short arm, while the latter lacked any of the 25 Y-specific loci. These findings may suggest the existence of a non-Y gene that is controlled by the testis-determining factor on the short arm of the Y chromosome and has a role in the testis formation in man.

Adult↗
PubMed1992

Maternal serum folate and zinc concentrations and their relationships to pregnancy outcome.

To evaluate the relationship between folate and zinc, and its effect on pregnancy outcome, maternal serum folate and zinc concentrations were determined at 18 and 30 wk gestation in a defined population of 285 pregnant women as part of a large-scale study to identify risk factors for fetal growth retardation (FGR). These results were correlated with birth weight and Apgar scores of newborn infants and with maternal infections during the perinatal period. A weak linear relationship was observed between maternal serum folate and zinc concentrations at 30 wk gestation. Folic acid supplementation had favorable effects on birth weight and Apgar scores of newborns, and reduced prevalence of FGR and maternal infections. No significant correlation was found between serum zinc concentration and birth weight of infants. The concept that folic acid supplementation has an adverse effect on maternal zinc nutriture and pregnancy outcome was not supported.

Adult↗
PubMed1992

Chemotherapy-induced anemia in patients with primary lung cancer.

To elucidate the factors which influence the value of hemoglobin, the nadir value of hemoglobin, frequency of blood transfusion and prognostic value of blood transfusion in patients with primary lung cancer during intensive chemotherapy, the hematological features of 124 patients entered into a randomized phase III study containing cisplatin were retrospectively analyzed. There was no difference in the percent nadir hemoglobin value of the first course of chemotherapy (% of pretreatment value) in any of the subgroups with respect to sex, body weight loss, performance status, age, stage, number of metastatic sites or treatment arms. The only predictive indicator for the nadir hemoglobin value in the first course of chemotherapy was the pretreatment value of hemoglobin. The equation for the regression line was y = 1.07 + 0.73x (R2 = 0.663, p < 0.001). The lowest nadir hemoglobin value (% of pretreatment value) during all chemotherapy courses was significantly lower in the subgroups older than 60 years and those with body weight loss. There was an inverse correlation between the accumulated dose of cisplatin and the lowest nadir hemoglobin value (p < 0.05). The frequency of blood transfusion in patients with more than two metastatic sites was significantly higher than in those with one or no metastatic sites (p < 0.05). Survival of patients who had required blood transfusion after chemotherapy was significantly shorter than that of patients who had not (p < 0.05).

Adult↗
PubMed1992

Increase in potential activities of protein phosphatases PP1 and PP2A in lymphoid tissues of autoimmune MRL/MpJ-lpr/lpr mice.

The differential assay conditions for protein phosphatases PP1, PP2A, and PP2C were extensively studied by using crude extracts from mouse lymphoid tissues as enzyme sources. Under these conditions, the protein phosphatase activities were measured in MRL/MpJ-lpr/lpr mice (MRL/lpr mice), autoimmune-prone mice, and MRL/MpJ(-)+/+ mice (MRL/+/+ mice) and C3H/HeJ mice as the controls. In MRL/lpr mice, significant alterations in protein phosphatase activities from those in the control mice were demonstrated. In spleen and liver from MRL/lpr mice, potential activities of PP1 and PP2A were distinctly elevated over those of the control mice. These elevations appeared to be due to accumulation of the abnormal lymphocytes that emerged in MRL/lpr mice. Although the PP1 activity in MRL/lpr lymph nodes was lower than those of normal spleen and thymus, it was greatly increased by Co(2+)-trypsin treatment so that the PP1 activity of MRL/lpr lymph nodes was the highest among those of all the tissues examined. In contrast, PP2C activity showed no remarkable alteration in the autoimmune disease model mice as compared with that in the control mice. These results demonstrated a specific elevation in potency of protein dephosphorylation in the tissues of MRL/lpr mice, suggesting a new explanation for the defect in signal transduction in this disease.

Animals↗
PubMed1992

Molecular cloning of cDNAs for rat proteasomes: deduced primary structures of four other subunits.

Proteasomes (multi-protease complexes) are composed of approximately 15 non-identical subunits of similar sizes (molecular weight = 21-32 kDa), but different charges (isoelectric point = 4-9). Previously, we deduced the primary structures of 6 subunits of rat proteasomes by recombinant DNA techniques. In this paper we report the nucleotide sequences of 4 other subunits, rIOTA, rZETA, rDELTA, and rRING12, determined from cDNA clones isolated by screening a rat H4TG hepatoma cell cDNA library with the cDNAs of their human counterparts as probes. The polypeptides deduced from their nucleotide sequences consisted of 246, 241, 202, and 219 amino acid residues with calculated molecular weights of 27,399, 26,391, 21,649, and 23,324, and calculated isoelectric points of 6.37, 4.65, 4.84, and 4.70, respectively. These results and previous findings indicate that the primary structures of the subunits of rat proteasomes show considerably high inter-subunit homology, but can be classified into apparently distinct sub-groups, suggesting that rat proteasome genes form a multi-gene family with the same evolutionary origin, but have diverged during evolution to acquire possibly subunit-specific functions.

Amino Acid Sequence↗
PubMed1992

Malignant pleural mesothelioma producing human chorionic gonadotropin. Report of two cases.

Two cases of malignant pleural tumor producing human chorionic gonadotropin, one confirmed at surgery and autopsy and the other by biopsy, are reported. Both of the patients had bilateral gynecomastia with high levels of serum human chorionic gonadotropin. The first patient underwent panpleuropneumonectomy because of diffuse malignant pleural tumor, but died five months later due to recurrent disease. The histological diagnosis was diffuse, malignant, monophasic mesothelioma of the epithelial type. Immunostaining for alpha-, beta-human chorionic gonadotropin and human placental lactogen was positive in syncytiotrophoblast-like cells. The second patient had diffuse pleural tumor with massive effusion. A pleural biopsy specimen showed diffuse proliferation of epithelioid large cells. Immunostaining for alpha, beta-human chorionic gonadotropin and human placental lactogen was positive in mono- and multinucleated bizarre giant cells mimicking trophoblasts. A diagnosis of malignant mesothelioma with trophoblastic differentiation seemed most likely in both cases in view of the clinical and pathological findings. In both cases, results of mucin histochemistry and various immunohistochemical stains for antigens or with antibodies were consistent with diagnosis of mesothelioma except in a few cells in the choriocarcinomatous portion. This may be the first report describing human chorionic gonadotropin-producing malignant mesotheliomas of the pleura.

Adult↗
PubMed1992

Reaction of sevoflurane and its degradation products with soda lime. Toxicity of the byproducts.

Sevoflurane previously has been reported to undergo extensive degradation in the presence of soda lime. To more completely characterize the extent and significnce of this reaction, we studied degradation of sevoflurane with and without soda lime, as well as the toxicity and mutagenicity of the degradation products. Two degradation products detected were CF2 = C(CF3)OCH2F (compound A) and CH3OCF2CH(CF3)OCH2F (compound B). During circulation of 1%, 2%, and 3% sevoflurance in a closed anesthesia circuit for 8 h, peak concentrations of compound A were 13.3 +/- 0.27, 30.2 +/- 0.10, and 42.1 +/- 1.07 ppm at 2 h, respectively. The concentrations of compound B did not exceed 2 ppm. The temperature of the soda lime was 43.3 +/- 2.8 degrees C at 1 h and increased gradually to 47.9 +/- 1.5 degrees C after 8 h. In closed flasks with soda lime, the magnitude of the decrease in sevoflurance concentrations (3%) and of the increase in compound A concentrations was temperature dependent. The peak concentrations of compound A at 23 degrees C, 37 degrees C, and 54 degrees C were 32.8 +/- 6.8 at 2 h, 46.6 +/- 1.0 at 0.5 h, and 78.5 +/- 2.3 ppm at 0.5 h, respectively. The LC50 (50% lethal concentration) of compound A in Wistar rats was 1,090 ppm in males and 1,050 ppm in females exposed for 1 h. The LC50 was 420 ppm in males and 400 ppm in females exposed for 3 h. The chronic toxicity of compound A in Wistar rats was studied by exposing rats 24 times, for 3 h each, to initial concentrations of 30, 60, or 120 ppm in a ventilated chamber. At all concentrations, there were no apparent effects other than a loss of body weight in females (120 ppm) on the final day (P < 0.01). Compound A did not induce mutation on the reverse (Ames) test at less than 2,500 micrograms/dish (culture medium 2.7 ml) with activation by S-9 mixture, and below 1,250 micrograms/dish (culture medium 2.7 ml) without activation, in four strains of S. typhimurium and in 1 strain of E. coli. Exposure of fibroblasts to 7,500 ppm of compound A for 1 h, compound A did not induce structural change. In a study of acute toxicity of compound B, there was no toxicity in Wistar rats after 3 h of exposure at 2,400 ppm. The reverse (Ames) test for compound B was negative at 625-1,250 micrograms/dish.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗
PubMed1992

Evaluation of three nutritional assessment methods in a group of women.

We conducted a reproducibility study of four 24-hour dietary recalls (N = 224) and four biochemical assessments of nutritional status (N = 265) in a group of women in Alabama. For 24-hour recalls, the variance component ratios were all greater than 1, and the intraclass correlation coefficients ranged from 0.16 to 0.27 for macronutrients, and from 0.09 to 0.37 for vitamins and minerals. The intraclass correlation coefficients for biochemical assessments ranged between 0.39 and 0.74 with corresponding variance component ratios of 1 or below for most nutrients. The correlation coefficients between the food frequency questionnaire on the usual dietary intake during the year preceding the beginning of study and the mean values of four 24-hour dietary recalls administered at the initial visit and again after 2, 4, and 6 months ranged from 0.3 to 0.4 for most nutrients. We found plasma beta-carotene levels to be moderately correlated with dietary vitamin A (r = 0.20) and beta-carotene (r = 0.22).

Adult↗
PubMed1992

Ambulatory oxygen uptake measurement system.

An apparatus for monitoring prolonged measurement of oxygen uptake without discomfort has been developed. The system is based on the open flow-through principle. The subject wears a hood through which air is drawn by an exhaust blower. Oxygen concentration is kept constant by a servo-controlled blower, so that flow rate is essentially proportional to oxygen uptake. The flow rate of the main stream is measured by a time-of-flight flowmeter located in the exhaust hose. Oxygen concentration is measured by a limiting-current oxygen sensor. The signals representing flow rate and oxygen concentration are digitized and stored in a memory. All of the equipment is assembled in a small package (wt = 3 kg) which the subject carries on his back. The memory chip is removed from the portable device after each experiment. Data are transferred from the memory to a microcomputer and then an oxygen uptake trend is estimated. Response of the system to a step input is about 30 s. Compared with a commercially available oxygen monitoring system (Magna 88, P. K. Morgan Ltd., Rainham, UK), the maximum difference was 0.15 L/min within an oxygen uptake range of 0.25-2.3 L/min. Thus, the measurements made with our portable device agree with the results obtained using the conventional method.

Adult↗
PubMed1992

A Y-associated allele may be characteristic of certain ethnic groups in Asia.

The probe 47z detects DNA polymorphisms on both the X and Y chromosomes. Blood samples were collected from Korean, Chinese, Jewish, Caucasian and Negro populations and polymorphisms of both loci were compared with findings previously reported in Japanese. Both Y1 and Y2 alleles were detected in Japanese and Koreans. However, only the Y1 allele was detected in each of the other populations. Although, both X1 and X2 alleles were detected in all examined populations, the frequency of the X2 allele was very low among Negroes.

Alleles↗
PubMed1992

Connectedness versus separateness: applicability of family therapy to Japanese families.

This article, a product of the two authors' multicultural experiences, contrasts British and Japanese families in order to examine the applicability of the Western model of family therapy to Japanese families and therapists. Areas where the Western model is incompatible are identified, and modifications to fit the Japanese indigenous model are suggested. The most significant difference in value systems between the two cultures is the Japanese preference for connectedness. The Japanese person is seen as a part of the embedded interconnectedness of relationships, whereas British norms prioritize separateness and clear boundaries in relationships, individuality, and autonomy. This value orientation is manifested in the Japanese language, hierarchical nature of the family structure, the family life cycle, and the implicit communication style. Systemic thinking, which deals with the pattern of relationships, is valid for all families regardless of cultural differences. But therapists should note that the preferred direction of change for Japanese families in therapy, is toward a process of integration--how a person can be effectively integrated into the given system--rather than a process of differentiation. An authoritative therapist style, the use of individual sessions, silence, and other nonverbal techniques are relevant to bringing about the desired change toward better integration of the individual with his or her networks.

Adolescent↗
PubMed1992

Monoclonal antibodies against the native urease of Helicobacter pylori: synergistic inhibition of urease activity by monoclonal antibody combinations.

Monoclonal antibodies (MAbs) against the native urease of Helicobacter pylori NCTC 11637 were found to clearly inhibit the urease activity. Interestingly, synergistic inhibition by two MAbs recognizing different subunits was also observed. Ten MAbs were produced and classified as two isotypes of the immunoglobulin G (IgG) subclass, IgG1, and IgG2a. Western blot (immunoblot) analysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that five MAbs recognized the large subunit and the other five recognized the small subunit of the urease. Among the MAbs, L2 and S2, which recognized the large and the small subunits, respectively, were also able to inhibit the urease activity of clinical isolates from H. pylori-infected patients. The combination of L2 and S2 led to augmented synergistic inhibition. L2, but not S2, could also inhibit the urease activity from Helicobacter mustelae; enzyme-linked immunosorbent assay and Western blot analysis showed that L2 cross-reacted with this urease. These results suggested that the epitope recognized by L2 had a structure common to both Helicobacter species and may be involved in the active site of the urease. In contrast to the MAbs, a polyclonal antibody in sera from mice immunized with H. pylori urease did not have the ability to inhibit H. pylori urease activity. However, the polyclonal antibody retained the ability to abolish the inhibitory action of these MAbs. Moreover, other MAbs which could not inhibit H. pylori urease activity also abolished the inhibitory action.

Antibodies, Bacterial↗
PubMed1992

Modulation of progesterone secretion by androgens in porcine granulosa cell cultures.

The influence of testosterone, androstenedione and dihydrotestosterone (DHT) on the progesterone (P4) production by cultured porcine granulosa cells was studied in the presence or absence of gonadotropins. Porcine granulosa cells from large follicles (6-12 mm in diameter) were incubated for 2 days with 5% CO2 in air with testosterone, androstenedione and DHT (10(-12), 10(-10), 10(-8) and 10(-6) M) in the presence or absence of luteinizing hormone (LH, 10 ng/ml) or follicle-stimulating hormone (FSH, 30 ng/ml). P4 and pregnenolone (P5) in conditioned culture media were quantified by their specific RIAs. In the absence of gonadotropins, P4 in media with androgens were not significantly different from controls. In the presence of LH, the addition of testosterone (10(-10), 10(-8) M), androstenedione (10(-8) M) and DHT (10(-8) M) caused a significant 1.3- to 2.3-fold increase in P4 over that caused by LH alone. In contrast, in the presence of FSH, testosterone (10(-12), 10(-10) M), androstenedione (10(-12)-10(-6) M) and DHT (10(-6) M) reduced the levels of P4 by 22% to 41%. The addition of androgens with LH caused a significant increase in P5, while P5 decreased in the presence of FSH. P4/P5 ratios remained unchanged in the presence of both LH and FSH. These data suggest that the P4 production by cultured porcine granulosa cells is modulated in a paracrine or an autocrine fashion by androgens in the presence of gonadotropins, and that androgens may exert their actions partly by altering the activity of cholesterol side chain cleavage enzymes.

Androgens↗
PubMed1992

Nutrient levels in amniotic fluid from women with normal and neural tube defect pregnancies.

We analyzed nutrient levels in amniotic fluid obtained during the second trimester of normal, uncomplicated pregnancies from 221 women who delivered apparently healthy infants and from 8 with neural tube defect (NTD) pregnancies. Folate was measured by microbiological assay, vitamin B12 by a radiobinding method, and zinc, copper and iron by atomic absorption spectrophotometry. We found that the mean amniotic fluid nutrient levels of normal pregnancies were 24.7 nmol/l for folate, 600 pmol/l for vitamin B12, and 1.7, 1.9, and 9.0 mumol/l for zinc, copper and iron, respectively. Amniotic fluid folate, zinc, copper and iron levels of NTD pregnancies were similar to those found during normal pregnancy, however, vitamin B12 levels were markedly lower than those of normal pregnancies.

Adolescent↗
PubMed1992

Increasing aromatase cytochrome P-450 level in human placenta during pregnancy: studied by immunohistochemistry and enzyme-linked immunosorbent assay.

We investigated the immunohistochemical localization of aromatase cytochrome P-450 (P-450arom) using a specific polyclonal antiserum (PAb R-8-2). We compared catalytic activity, as detected by the tritiated water assay, and tissue levels of P-450arom, as detected by the specific enzyme-linked immunosorbent assay, in placental samples from early pregnancy to term. Immunostaining and subsequent detection by light and electron microscopy demonstrated that P-450arom is localized in the microvilli and endoplasmic reticulum of the syncytiotrophoblasts of the chorionic villi, but is not present in the mitochondria, nuclei, or cytotrophoblasts at any time during gestation. The P-450arom concentration and aromatase activity were greater in the microsomal fraction than in the mitochondrial fraction or total homogenate at each gestational stage and increased linearly as pregnancy progressed. However, the specific activity of P-450arom was comparable among subcellular fractions in each gestational period. These results suggest that the nature and localization of P-450arom are unchangeable, and the P-450arom concentration increases during pregnancy. It appears that the aromatase detected in the mitochondrial fraction is a contamination of microsomal aromatase, and the increase in aromatase activity can be attributed to an increase in the number of P-450arom molecules rather than an increase in the catalytic ability of each molecule.

Aromatase↗
PubMed1992

7-Oxodihydrokarounidiol [7-oxo-D:C-friedo-olean-8-ene-3 alpha,29-diol], a novel triterpene from Trichosanthes kirilowii.

The structure of 7-oxodihydrokarounidiol [7-oxo-D:C-friedo-olean-8-ene-3 alpha,29-diol], isolates from the seeds of Trichosanthes kirilowii (Cucurbitaceae), was determined by chemical correlation with karounidiol [D:C-friedo-oleana-7,9(11)-diene-3 alpha,29-diol] from the same source. Two other natural products, viz. bryonolic acid (3 beta-hydroxy-D:C-friedo-olean-8-en-29-oic acid) and bryononic acid (3-oxo-D:C-friedo-olean-8-en-29-oic acid), were also correlated with karounidiol.

Magnetic Resonance Spectroscopy↗