Biomedical subjects

T Tamura

Publications and source records attributed to T Tamura.

At least 757 records · Page 42Linked to original sources

PubMed1992

Clinical significance of serum colloid osmotic pressure in relation to pulmonary edema and coronary instability in patients with unstable angina.

Several investigators demonstrated that severe reduction of colloid osmotic pressure (COP) predicts a fatal outcome in patients with cardiopulmonary failure. To evaluate the clinical significance of COP in relation to pulmonary edema, we studied 117 patients with unstable angina admitted in the hospital within 24 h after the chest pain. The mean COP of all 117 patients was 24.8 +/- 3.7 mmHg. COP was significantly lower in patients with pulmonary edema, according to the chest x-ray findings, compared with the patients without it. Among 26 patients with emergency coronary arteriography, a fairly good correlation was observed between coronary jeopardy score and COP (r = -0.57, p less than 0.005). Furthermore, COP in patients who survived 26 months after the hospital discharge was significantly higher than that of the nonsurvivors. Thus, measurement of COP is advised for monitoring patients with unstable angina.

Angina, Unstable↗

PubMed1992

Preparation and characterization of a mouse osteoclast-like multinucleated cell population.

We have reported that numerous tartrate-resistant acid phosphatase-positive osteoclast-like multinucleated cells (TRAP+ MNCs) are formed when mouse osteoblastic cells and spleen cells are cocultured in the presence of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] (Endocrinology 123:2600, 1988). In this study, we prepared a TRAP+ MNC population using a modified coculture system and examined its osteoclastic properties. TRAP+ MNCs were formed in cocultures of mouse osteoblastic cells and marrow cells on 10 cm collagen gel-coated dishes. The TRAP+ MNC population was prepared by treating the dishes with 0.2% bacterial collagenase followed by density gradient centrifugation. The yield of TRAP+ MNCs was 20,000-40,000 cells per dish, much higher than that of osteoclasts (OCLs) isolated from neonatal rat bones (approximately 1000 cells per head). The purity of TRAP+ MNCs was 5.6 +/- 0.6% in cell number and about 30% in the number of nuclei. The recovery of TRAP+ MNCs after density gradient centrifugation was 30-40%. Acid production by MNCs was demonstrated by vital staining with acridine orange. Numerous resorption pits were formed when the MNC population was cultured for 48 h on bone slices. Autoradiography using [125I]salmon calcitonin (CT) showed abundant CT binding in most TRAP+ MNCs. Saturation analysis of [125I]salmon CT indicated a dissociation constant Kd for TRAP+ MNCs of 8.9 +/- 0.7 x 10(-10) M and 16.5 +/- 1.5 x 10(6) binding sites per cell. These results were similar to the Kd value (3.5 x 10(-10) M) and the number of binding sites (3.3 x 10(6) per cell) in isolated rat OCLs. Displacement curves for [125I]salmon CT with unlabeled salmon and human CT were similar in MNC and OCL preparations. Salmon and human CT increased cAMP production (maximal response: slmon CT at 10(-10) M, human CT at 10(-8) M; ED50s: salmon CT, 2.2 x 10(-11) M, human CT, 1.3 x 10(-9) M) in the MNC preparation. These results indicate that a large number of mouse TRAP+ MNCs possessing OCL characteristics can be easily prepared from in vitro cultures. This procedure will facilitate examination of mammalian OCL functions.

Acid Phosphatase↗

PubMed1992

Mechanism of action of amylin in bone.

Amylin is a 37 amino acid peptide produced mainly by beta-cells of the endocrine pancreas. Human amylin has 43% homology with human calcitonin gene-related peptide (CGRP) and 13% homology with human calcitonin (CT). Amylin and CGRP have been reported to have CT-like hypocalcemic activity in vivo. To investigate the role of amylin in bone, we examined the mechanisms of action of human amylin, CGRP, and CT in osteoclasts and osteoblasts. Both human amylin and CGRP inhibited 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3]- induced bone resorption in an organ culture system, and the potencies of the two peptides were similarly approximately 60-fold lower than that of human CT. Using a recently developed procedure for preparing large numbers of osteoclast-like multinucleated cells (MNCs) formed in co-cultures of mouse osteoblasts and bone marrow cells in the presence of 1 alpha,25(OH)2D3, we found that both human amylin and CGRP stimulated cAMP production in osteoclast-like MNCs, but only at 60-fold higher concentrations than human CT. Specific binding of [125I]-human CT to osteoclast-like MNCs was detected (dissociation constant, 3 x 10(-8) M; binding sites, 3 x 10(7) per cell). To displace the bound [125I]-human CT from osteoclast-like MNCs, about 170-fold higher concentrations of human amylin and CGRP were required. No specific bindings of [125I]-amylin and [125I]-CGRP to osteoclast-like MNCs could be detected. Human CGRP stimulated cAMP production both in established mouse osteoblast-like cells (KS-4) and in mouse primary osteoblast-like cells. Amylin was a weak agonist for cAMP production in KS-4 cells. The increment in cAMP production induced by CGRP and amylin was abolished by the addition of human CGRP(8-37), a selective antagonist for CGRP receptors. CT did not stimulate cAMP production in KS-4 cells. Amylin, but not CT, displaced the bound [125I]-human CGRP from rat brain membranes. These results indicate that amylin binds not only to CT receptors in osteoclast-like MNCs but also to CGRP receptors in osteoblasts. The relative potencies of these compounds to induce cAMP production was CT greater than amylin not equal to CGRP in osteoclast-like MNCs and CGRP greater amylin much greater than CT in osteoblast-like cells.

Amyloid↗

PubMed1992

Isolation and characterization of a cDNA clone encoding the TATA box-binding protein (TFIID) from wheat.

We isolated a complementary DNA (cDNA) encoding the TATA-binding factor 'TFIID' from a wheat seedling cDNA library. The wheat TFIID transcript of 1.2 kb poly(A)+ RNA was expressed at a low level early in germination, but gradually increased as the seedlings developed. In vitro binding experiments showed that the bacterially expressed wheat TFIID protein could specifically bind to the TATA boxes of the cauliflower mosaic virus (CaMV) 35S, wheat histone H3 and adenovirus major late genes with different affinity. A comparison with Arabidopsis TFIID showed the presence of a plant-specific region consisting of 13 amino acids at the divergent amino terminus and a conserved region (182 amino acids) at the carboxy terminus longer than that observed in yeasts (180 amino acids) and animals (181 amino acids).

Amino Acid Sequence↗

PubMed1992

DNA analyses of XX and XX-hypospadiac males.

Fourteen 46,XX "males" were analyzed by Southern blot hybridization with seventeen different Y chromosome-derived DNA probes and by the polymerase chain reaction for an additional two sites on the short arm of Y. Eight 46,XX males possessed various segments of the short arm of the Y chromosome, including the sex determining region. The detected segments ranged from the two most distal loci to nearly the entire length of the short arm, viz., 10 out of 11 loci. None of the eight patients had hypospadia. Five out of the six remaining cases had hypospadia and no Y sequence was detected, suggesting the presence of a causative difference between hypospadiac and non-hypospadiac groups.

Adolescent↗

PubMed1992

The majority of the marker chromosomes in Japanese patients with stigmata of Turner syndrome are derived from Y chromosomes.

DNA analyses of 41 individuals with stigmata of Turner syndrome and a 45,X/46,X+mar or 46,X+mar karyotype were carried out. Southern-blot analysis employing 17 Y-specific probes were used to determine whether the marker chromosome was Y-chromosomal in origin. Of the 41 DNA samples from these patients, 23 contained detectable Y-chromosomal DNA. Points of chromosome breakage were distributed over the entire length of the Y long arm. Three individuals, who carry different portions of the Y chromosome, had developed gonadoblastoma. GBY (the gonadoblastoma locus on the Y chromosome) is mapped proximal to DYS132, midway between the 13 Yq loci that we have studied. We also used a polymerase chain reaction technique that could detect 7 loci over the length of the Y chromosome. This technique may be useful for the rapid assessment of marker chromosomes, especially for evaluating the risk of gonadoblastoma.

Blotting, Southern↗

PubMed1992

Chemically defined medium for the production of biologically active substances of CHO cells.

A recombinant CHO cell line (GT19) secreting a high level of human growth hormone (hGH) was constructed with amplification of the introduced hGH gene. The cells grew well in the alpha MEM medium supplemented with 5% dialyzed fetal calf serum (dFCS), but not with less than 1% dFCS. Therefore we examined various medium components and obtained an improved medium which supported cell growth at low serum concentrations. The production of hGH by the cells was also enhanced in this medium.

Animals↗

PubMed1992

A prognostic-factor risk index in advanced non-small-cell lung cancer treated with cisplatin-containing combination chemotherapy.

Prognostic factors for response and survival were retrospectively evaluated in 192 previously untreated patients with advanced non-small-cell lung cancer (NSCLC) who had received either vindesine plus cisplatin or mitomycin plus vindesine plus cisplatin as initial treatment. Univariate analysis demonstrated that squamous-cell histology, early stage, and a small number of metastatic sites were favorable prognostic factors for response to chemotherapy. Multivariate analysis using Cox's proportional hazard model indicated that the number of metastatic sites was the only significant pretreatment factor for response (P = 0.0005). Multivariate regression analysis revealed that the number of metastatic sites (P = 0.0002), sex (P = 0.0009), serum albumen levels (P = 0.0018), performance status (P = 0.0026) and lactic dehydrogenase values (P = 0.0026) contributed independently to survival. On the basis of these five prognostic factors, a prognostic index for survival was used to define three prognostic groupings (good, intermediate, and poor) for survival (median survival, 16.5 vs 9.4 vs 4.6 months; P = 0.0001). This particular regression model should aid in the design and analysis of new treatment strategies and may be useful for indirect comparisons of different studies carried out in similar patient populations.

Adenocarcinoma↗

PubMed1992

A new 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for testing macrophage cytotoxicity to L1210 and its drug-resistant cell lines in vitro.

Activated by interferon gamma (IFN gamma)(50 U/ml) and lipopolysaccharide (50 ng/ml), mouse peritoneal macrophages were cocultured with the L1210 parental cell line (L1210/PRT) and its Adriamycin-, cisplatin-resistant cell lines (L1210/ADM, L1210/CDDP) for 24 h at effector: target (E:T) ratios of 10:1, 5:1 and 2:1. The direct 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT)-cleavage assay, a new improved indirect MTT assay, and the colony-formation assay were used to quantify macrophage-mediated suppression of these non-adherent tumour targets. The results showed that the macrophages can produce formazan at a high level, which can interfere with the final results of a direct MTT assay. The new indirect MTT assay can avoid such interference because the effectors are separated from the targets before the assay is performed, so the real viability of the targets is reflected. An indirect MTT assay, as developed in this study, could be better than the direct assay for examining the suppressive effect of activated macrophages on non-adherent tumour cells in vitro. This study also revealed that all the L1210 cell lines can be suppressed significantly by the macrophages at E:T ratios of 10:1 and 5:1 while the two drug-resistant cell lines have lower survival rates at an E:T ratio of 10:1, indicating that they are more susceptible than their parental cell line.

Animals↗

PubMed1992

Isolation of 2 novel RFLP markers and their localization at 2q35 by microdissection and subsequent enzymatic amplification.

We previously constructed a chromosome 2q-specific genomic library and isolated a number of microclones. In the present study, we first analyzed with Southern hybridization whether any of the microclones represent restriction fragment length polymorphisms (RFLPs), and then tried to map RFLP markers physically, using the recently developed chromosome microdissection/enzymatic amplification method. Of 13 clones analyzed, two were RFLP markers; a clone, pM2C83, showed a four-allele MspI RFLP, and the other, pM2C8, a two-allele RsaI RFLP. In order to assign the two polymorphic markers, two chromosomal segments, 2q32-q35 and 2q35-qter, on the chromosome 2 from a karyotypically normal person were microdissected, and the DNA from each segment was amplified with the polymerase chain reaction (PCR) using marker sequence-specific primers. With this method, both of the clones were assigned to 2q35. These two RFLP markers must be useful for linkage analysis of genetic diseases whose loci are at around 2q35.

Base Sequence↗

PubMed1992

Localization of 24 cosmid clones on the human Y chromosome.

Twenty-four novel cosmid clones were cloned and mapped on the human Y chromosome using a panel consisting of DNA from seven individuals each having a different segment of the Y chromosome. Eight were assigned to the short arm, 15 to the long arm and 1 to the both short and long arms.

Animals↗

PubMed1992

DNA analysis of two patients with a non-fluorescent Y chromosome.

Results of DNA study on two patients of gonadal dysgenesis with a 45,X/46,X,Ynf (non-fluorescent Y chromosome) karyotype are described. In one patient who developed gonadoblastoma, all 12 loci on the non-fluorescent part of Yq were detected. Another patient did not have gonadoblastoma at 20 years, and only the proximal 6 loci out of 12 were detected.

Adult↗

PubMed1992

PCR detection of structurally abnormal Y chromosomes.

Three probes each detecting a locus on the proximal long arm of the Y chromosome were partially sequenced. Thus, 3 sets of novel primers were developed which enable PCR detection of these 3 loci. Five previously reported primer sets, 3 on the short arm and each one on the centromere and the distal long arm, were mapped along with the novel three using a mapping panel consisted of 8 patients each with different structural abnormality of the Y chromosome. Now, PCR detection of these 8 loci covering an entire length of the Y chromosome has become possible enabling rapid screening of patients with Y chromosome aberrations.

Base Sequence↗

PubMed1992

Oral folic acid supplementation for cervical dysplasia: a clinical intervention trial.

OBJECTIVE: We attempted to evaluate the effect of oral folic acid supplementation on the course of cervical dysplasia. STUDY DESIGN: A total of 235 subjects with grade 1 or 2 cervical intraepithelial neoplasia were randomly assigned to receive either 10 mg of folic acid or a placebo daily for 6 months. Clinical status, human papillomavirus type 16 infection, and blood folate levels were monitored at 2-month intervals. Outcome data were subjected to chi 2 analysis. RESULTS: The prevalence of human papillomavirus type 16 infection initially was 16% among subjects in the upper tertile of red blood cell folate versus 37% in the lower tertile (trend p = 0.035). After 6 months no significant differences were observed between supplemented and unsupplemented subjects regarding dysplasia status, biopsy results, or prevalence of human papillomavirus type 16 infection. CONCLUSION: Folate deficiency may be involved as a cocarcinogen during the initiation of cervical dysplasia, but folic acid supplements do not alter the course of established disease.

Administration, Oral↗

PubMed1992

Acute pulmonary edema after Blalock-Taussig anastomosis.

Acute pulmonary edema developed in 2 patients after a Blalock-Taussig shunt procedure. Both patients had a univentricular heart complex with pulmonary stenosis. One patient underwent a modified Blalock-Taussig shunt using a polytetrafluoroethylene tube and the other underwent a classic Blalock-Taussig anastomosis. Acute pulmonary edema after the Blalock-Taussig shunt is rare, but once it has occurred, immediate treatment is obligatory.

Acute Disease↗

PubMed1992

Induction of IL-2 receptor expression and proliferation of T cell clones by a novel cytokine(s).

We found a unique T cell IL-2 receptor (IL-2R)3-inducing activity in the supernatant (SN) of the TH1 clone stimulated with antigen on spleen cells as antigen-presenting cells (APC). We have tentatively named this activity the IL-2R-inducing factor (IL-2RIF) and have characterized the activity. The SN induced IL-2R and proliferation of TH1 clones stimulated with B cell APC, which could not induce IL-2R in the absence of the SN. Other known cytokines were examined for a IL-2RIF activity; however, none of cytokines examined exerted a similar activity. Moreover, the neutralizing antibodies against the known cytokines tested did not block the IL-2RIF activity in the SN. When TH1 clones were stimulated with immobilized anti-CD3 or with fixed B cell APC in the presence of partially purified IL-2RIF, these clones expressed IL-2R and showed IL-2-dependent proliferation, whereas they induced neither IL-2R expression nor proliferation in the absence of IL-2RIF activity. These observations suggest that IL-2RIF activity is mediated by a novel cytokine(s) and the cytokine plays an important role as a second signal in the activation of the TH1 clone.

Animals↗

PubMed1992

Maternal alpha-2-macroglobulin levels and fetal growth in Guatemala.

Maternal serum alpha-2-macroglobulin (alpha 2M) levels were measured at the time of delivery in 244 women in the central highlands of Guatemala. Significantly higher alpha 2M levels were found in thin women and in poor women. In multiple regression analysis controlling for gestational age, race, sex, maternal triceps skinfold thickness and socioeconomic status, high alpha 2M levels were significantly associated with decreased birthweight. These findings agree with those in a predominantly black population in the United States and extend the relationship between alpha 2M and decreased birthweight to a developing country.

Biomarkers↗

PubMed1992

Differential macrophage-mediated cytotoxicity to P388 leukemia cells and its drug-resistant cells examined by a new MTT assay.

After activation by interferon-gamma (INF-gamma) and lipopolysaccharide(LPS), mouse peritoneal macrophages were cocultured with P388 parental cell line (P388/PRT) and its adriamycin (ADM)-, cisplatin(CDDP)-, cyclophosphamide(CPM)-, and mitomycin-C(MMC)-resistant cell lines for one day at effector:target ratios (E:T) of 10:1, 5:1, and 2:1. The direct 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) cleavage assay and a new indirect MTT assay as well as clonogenic assay were used to quantitate activated macrophage-mediated cytotoxicity to these non-adherent leukemia targets. The results revealed that all the P388 cell lines can be suppressed efficiently by activated macrophages, but P388 CPM- and MMC-resistant cell lines (P388/CPM, P388/MMC) were more susceptible than P388/PRT while P388 ADM- and CDDP-resistant cell lines (P388/ADM, P388/CDDP) shared equal level of survival rates with P388/PRT. This study also showed that both non-activated and activated macrophages can produce formazan in a high level, which can interfere with the final results of direct MTT assay. The new indirect MTT assay can avoid such interference by separating the effectors from the targets before performing the MTT assay and reflects the real viability of the targets so the indirect MTT assay developed in this study could be a better way to examine cytostatic and cytotoxic effect of activated macrophages on non-adherent tumor cells in vitro.

Animals↗