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Biomedical subjects

A Shinohara

Publications and source records attributed to A Shinohara.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Double oblique MR images of the shoulder: comparison with conventional images].

PURPOSE: Because the scapula is not only slanted on transverse sections but also inclines on sagittal section, we now perform shoulder MR imaging using double oblique images (DOI), which are planes perpendicular or parallel to the long axis of the scapula obtained with oblique sagittal scout imaging. The purpose of this study was to evaluate the usefulness of double oblique shoulder MR imaging. MATERIALS AND METHODS: MR images of shoulders with operatively or arthroscopically proven lesions (20 cases) that had been examined on both conventional images (CI) and DOI were retrospectively reviewed. DOI were compared with CI not only in terms of diagnostic performance but also in their ability to identify the details of shoulder anatomy. All MR studies were done with a shoulder coil on a high-field (1.5T) unit. RESULTS: Although the accuracy of DOI in diagnosing shoulder disorders such as rotator cuff tear and labrum injury was not as good as that of CI, DOI were better for identifying or discriminating muscles and tendons of the rotator cuff, labralbicipital junction and anterior band of the inferior gleno-humeral ligament, and for recognizing the correct position of the glenoid labrum. CONCLUSION: MR double oblique imaging of the shoulder provides more detailed information about shoulder anatomy and disorders than conventional imaging.

Adolescent↗
PubMed1998

[MR diagnosis of internal derangement of the knee by SE T1 and GRE T2* weighted images: evaluation of 300 arthroscopically proven knees].

To evaluate whether or not the combination of sagittal and coronal spin-echo (SE) T1 and sagittal gradient echo (GRE) T2* weighted imaging is adequate to diagnose internal derangement of the knee, a study was done in 300 knees of 293 consecutive patients who underwent both MR imaging of the knee and arthroscopy. In prospective analysis, the MR imaging had an accuracy, sensitivity and specificity of more than 90% in the evaluation of medial meniscus (MM) and of 97% in the evaluation of anterior cruciate ligament (ACL). In the evaluation of lateral meniscus (LM), accuracy was 83%, sensitivity 76%, and specificity 88%. In a review of false-negative MR diagnoses (n = 42) of menisci, the most significant lesion was not in the meniscus but in the ACL in 32 knees (76%). Conservative treatment was selected in 25 knees (60%), rather than partial meniscectomy (n = 13) or meniscoresis (n = 4). There were 21 false-positive MR diagnoses of menisci even in retrospective analysis, and 17 of them (81%) had findings of tear in the posterior zone, which is known to be a difficult area for arthroscopic examination. The results were similar to those of other authors' with SE T1 and/or proton density and T2 weighted images. The combination of sagittal and coronal SE T1 and sagittal GRE T2* weighted images could be sufficient as a routine MR protocol for diagnosing the internal derangement of the knee.

Adolescent↗
PubMed1997

RAB22 and RAB163/mouse BRCA2: proteins that specifically interact with the RAD51 protein.

The human RAD51 protein is a homologue of the bacteria RecA and yeast RAD51 proteins that are involved in homologous recombination and DNA repair. RAD51 interacts with proteins involved in recombination and also with tumor suppressor proteins p53 and breast cancer susceptibility gene 1 (BRCA1). We have used the yeast two-hybrid system to clone murine cDNA sequences that encode two RAD51-associated molecules, RAB22 and RAB163. RAB163 encodes the C-terminal portion of mouse BRCA2, the homologue of the second breast cancer susceptibility gene protein in humans, demonstrating an in vitro association between RAD51 and BRCA2. RAB22 is a novel gene product that also interacts with RAD51 in vitro. To detect RAD51 interactions in vivo, we developed a transient nuclear focus assay that was used to demonstrate a complete colocalization of RAB22 with RAD51 in large nuclear foci.

Amino Acid Sequence↗
PubMed1997

Differential expressions of cyclin A and the retinoblastoma gene product in histological subtypes of lung cancer cell lines.

Cell-cycle-dependent phosphorylation of the tumor-suppressor protein product of the retinoblastoma gene (RB) is mediated by a family of cyclin-dependent kinases and cyclins. We examined the expressions of RB protein and cyclin A protein in 13 small-cell lung cancer (SCLC) lines and 14 non-small-cell lung cancer (NSCLC) lines by immunoblotting. RB protein was not present or was of a mutant type in 77% of the SCLC lines (10/13) but was present in all the NSCLC lines. Cyclin A was expressed in 38% of the SCLC lines (5/13) and in 86% of the NSCLC lines (12/14). A positive correlation (P = 0.0034) between expression of cyclin A and wild-type RB protein was found by Fisher's exact probability test. Densitometric analysis of the expression of RB protein in RB(+) lung cancer lines showed that the phosphorylated form was predominant in 2/3 of the SCLC and 8/14 of the NSCLC lines. The positive correlation between the expressions of RB protein and cyclin A suggests that RB protein in most RB(+) lung cancer cell lines is a target of cyclin-A-dependent kinase and that the tumor-suppressor function may be inactivated by phosphorylation.

Adenovirus E1A Proteins↗
PubMed1997

Saccharomyces cerevisiae recA homologues RAD51 and DMC1 have both distinct and overlapping roles in meiotic recombination.

BACKGROUND: Rad51 and Dmc1 are Saccharomyces cerevisiae homologues of the Escherichia coli recombination protein RecA. Mutant analysis has shown that both proteins are required for normal meiotic recombination, for timely and efficient formation of synaptonemal complex and for normal progression out from meiotic prophase. RESULTS: We have further characterized rad51 and dmc1 single mutants. A dmc1 mutation confers more severe defects in double strand break (DSB) resolution, crossover recombination and meiotic progression than does a rad51 mutant; in contrast, during return to growth, a rad51 mutation confers more severe defects in viability and intrachromosomal recombination than does a dmc1 mutation. Analysis of a rad51 dmc1 double mutant, in parallel with single mutants, shows that the double mutant is more defective with respect to the formation of crossovers during meiosis and, especially strikingly, with respect to interhomologue and intrachromosomal recombination during return to growth. Consistent with the observation of DMC1-dependent recombination in a rad51 mutant, subnuclear complexes of Dmc1 protein were detected for the first time in this mutant. In contrast to the effects on recombination, the effect of the double mutant on meiotic progression was similar to that of the rad51 single mutant. CONCLUSION: Rad51 and Dmc1 each make unique contributions to meiotic recombination. However, the two proteins are capable of substituting for one another under some circumstances, implying that they most likely share at least one recombination function. Recombination and cell cycle phenotypes are all consistent with the possibility that a dmc1 mutation causes an arrest of the post-DSB recombination complexes at a later, more stable stage than does a rad51 mutation.

Cell Cycle Proteins↗
PubMed1997

Characterization of the roles of the Saccharomyces cerevisiae RAD54 gene and a homologue of RAD54, RDH54/TID1, in mitosis and meiosis.

The RAD54 gene, which encodes a protein in the SWI2/SNF2 family, plays an important role in recombination and DNA repair in Saccharomyces cerevisiae. The yeast genome project revealed a homologue of RAD54, RDH54/TID1. Properties of the rdh54/tid1 mutant and the rad54 rdh54/tid1 double mutant are shown for mitosis and meiosis. The rad54 mutant is sensitive to the alkylating agent, methyl methanesulfonate (MMS), and is defective in interchromosomal and intrachromosomal gene conversion. The rdh54/tid1 single mutant, on the other hand, does not show any significant deficiency in mitosis. However, the rad54 rdh54/tid1 mutant is more sensitive to MMS and more defective in interchromosomal gene conversion than is the rad54 mutant, but shows the same frequency of intrachromosomal gene conversion as the rad54 mutant. These results suggest that RDH54/TID1 is involved in a minor pathway of mitotic recombination in the absence of R4D54. In meiosis, both single mutants produce viable spores at slightly reduced frequency. However, only the rdh54/tid1 mutant, but not the rad54 mutant, shows significant defects in recombination: retardation of the repair of meiosis-specific double-strand breaks (DSBs) and delayed formation of physical recombinants. Furthermore, the rad54 rdh54/tid1 double mutant is completely defective in meiosis, accumulating DSBs with more recessed ends than the wild type and producing fewer physical recombinants than the wild type. These results suggest that one of the differences between the late stages of mitotic recombination and meiotic recombination might be specified by differential dependency on the Rad54 and Rdh54/Tid1 proteins.

Amino Acid Sequence↗
PubMed1997

Mn SOD activity and protein in a patient with chromosome 6-linked autosomal recessive parkinsonism in comparison with Parkinson's disease and control.

We report Mn superoxide dismutase (SOD) protein and activity in a patient with familial autosomal recessive Lewy body-negative parkinsonism in comparison with patients with sporadic Parkinson's disease (PD) and controls. We recently proved linkage of this family with markers of chromosome 6 at 6q25.2-27, which included the Mn SOD gene. We used a novel polymorphic mutation at -9 position of the signal peptide of the Mn SOD precursor protein, which caused valine to alanine substitution. All the affected members of this family showed homozygosity for alanine, whereas nonaffected members, sporadic PD patients, and the control subjects studied showed either heterozygosity of alanine and valine or homozygosity of valine. The Mn SOD activity of this familial patient was the highest among the PD patients and the control subjects studied, and an abundant expression of Mn SOD was found in the substantia nigra. The molecular weight of Mn SOD protein by Western blotting of this patient was essentially similar to that of PD patients and the control subjects. High Mn SOD activity may constitute a genetic risk factor in this familial patient. The difference in the signal peptide sequence may affect the expression of Mn SOD within mitochondria; however, it is unlikely that loss of function type Mn SOD mutation is the cause of this familial parkinsonism. Mn SOD in sporadic PD patients was similar to that in controls.

Adult↗
PubMed1997

L-Myc overexpression and detection of auto-antibodies against L-Myc in both the serum and pleural effusion from a patient with non-small cell lung cancer.

Non-small cell lung cancer patient was found to have auto-antibodies against L-Myc in both the serum and pleural effusion. The titer of anti-L-Myc antibodies was higher in the pleural effusion than in the serum. Overexpression of L-Myc without DNA amplification was observed in the tumor cells. L-Myc antigen was not detected in either the serum or the pleural effusion. Anti-nuclear antibodies were also detected in both the serum and pleural effusion, although this patient did not have collagen-vascular disease.

Aged↗
PubMed1997

Distribution of terbium and increase of calcium concentration in the organs of mice i.v.-administered with terbium chloride.

To investigate the biological effects of terbium (Tb), male mice were intravenously administered with TbCl3 at 10, 25, or 50 mg Tb/kg. Time-course and dose-related changes in organ distributions of Tb were determined. More than 95% of the Tb in blood was in plasma, and the concentrations decreased rapidly. Contrary to normal pharmacokinetics, Tb concentrations in plasma were higher in the 10 mg/kg group than in the 50 mg/kg group. The concentrations after injection of 25 mg/kg were between 10 and 50 mg/kg injections. Tb was incorporated mainly in liver, lung, and spleen. In all groups more than 80% of Tb administered were found in these three organs. Disappearance of Tb in these organs was very slow. Tb was also found in kidney, heart and other organs. Coincidentally, it was found that the Ca concentration was increased in organs in which Tb was incorporated. After administration of Tb (50 mg/kg) the Ca concentration, compared to the controls, was 70-fold in spleen, 20-fold in lung, and 6-fold in liver. There were highly positive correlations between Tb and Ca concentrations in organs. Excretion of Tb in urine was 0.15-0.3% and that in feces was 1.7-12.5% for up to 7 days. These results indicate that liver, lung, and spleen are the main target organs of Tb administered intravenously, and that the increase in Ca concentrations is one of the important biological effects of Tb in target organs.

Animals↗
PubMed1996

S phase specific formation of the human Rad51 protein nuclear foci in lymphocytes.

The Rad51 protein, which is a homologue of the bacterial RecA protein, is involved in mitotic and meiotic recombination and in repair of double-strand breaks of DNA in yeast. The Rad51 homologue is conserved from yeast to human. In this study, the Rad51 protein was shown to be induced in peripheral blood lymphocytes (PBLs) 36 h after phytohemagglutinin (PHA) stimulation. Immunofluorescence study revealed that the distribution of the Rad51 protein in the nucleus was not uniform and focus-like staining was observed. Formation of the Rad51 foci was induced at 36 h after treatment of the cells with PHA. Twenty five percent of the cells had the foci at this time and the number of cells with foci declined thereafter. Cell cycle study using laser microscope by double staining method suggested that the appearance of the Rad51 nuclear foci was S phase specific. Furthermore, double staining study for the Rad51 protein and incorporated BrdU confirmed S phase specific appearance of the Rad51 nuclear foci. Formation of the Rad51 nuclear foci in PHA-stimulated lymphocytes might be involved in DNA recombination or DNA repair in S phase. The roles of RAD51 foci in S-phase will be discussed.

Cell Nucleus↗
PubMed1996

Stem-cell factor regulates the expression of cyclin A and retinoblastoma gene product in the growth and differentiation pathway of human megakaryocytic cells.

The biological effects of c-kit ligand (stem-cell factor: SCF) on an immortalized human megakaryocytic cell line (CMK) was evaluated using methods including the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, surface marker analysis, DNA cell-cycle analysis and immunoblotting. SCF stimulated the growth of CMK cells. Incubation with SCF resulted in increased expression of IIb/IIIa platelet-related glycoprotein (gpIIb, IIIa), indicating enhanced differentiation of CMK cells. Treatment of CMK cells with SCF resulted in a decrease in the subpopulation in the G1 phase, with a reciprocal increase in those in the S phase and the G2 + M phase. Moreover, SCF significantly increased cellular expression of cyclin A, a regulatory subunit of cyclin-dependent protein kinase (CDK), and the ratio of phosphorylated/dephosphorylated retinoblastoma gene product (RB protein). These results suggest that SCF stimulates the growth and differentiation of megakaryocytic cells possibly through mechanisms related to the activation of cell-cycle-dependent serine/threonine kinase and inactivation of the nuclear tumor-suppressor gene product.

Cell Differentiation↗
PubMed1996

Localization of mouse Rad51 and Lim15 proteins on meiotic chromosomes at late stages of prophase 1.

BACKGROUND: In meiosis, eukaryotic chromosomes show a series of morphological changes, during which chromosomes synapse and recombine. To understand the mechanisms of the morphological changes and recombination of chromosomes, we examined stage-specific localization of the Rad51 and Lim15 proteins on the chromosomes in meiotic prophase 1. These proteins are homologous with the RecA protein and have general properties of searching and pairing of homologous DNA sequences. We used mouse chromosomes whose small sizes allow us to identify the locations of these proteins on the entire structures of the chromosomes. RESULTS: In the leptotene and zygotene stages, the Rad51 protein was present on chromatin loops of mouse testis chromosomes then the protein left the loops. In the pachytene stage, the Rad51 protein was present almost exclusively along the core of the synaptonemal complexes (SC). When the stage proceeded to diplotene, the protein was present in the synaptic regions of chromosomes, in particular, in the chiasma regions. The protein was not present on separated homologous SC cores. On the other hand, the Lim15 protein that was found on chromatin loops in early prophase 1, was present almost exclusively at both ends of the SC cores throughout the late stages of prophase 1. CONCLUSION: The Rad51 and Lim15 proteins are present in chromatin loops when chromosomes form SC. The proteins may promote pairing of homologous DNA sequences that would lead formation of SC. The Rad51 protein in the SC cores may be involved in chiasma formation in late stages. The Lim15 protein, instead, may be involved in recombination in the telomeric region or in cohesion of sister chromatids for segregation.

Adenosine Triphosphatases↗
PubMed1996

Indices of lead-exposure in blood and urine of lead-exposed workers and concentrations of major and trace elements and activities of SOD, GSH-Px and catalase in their blood.

Seventy male factory workers were studied. The lead concentrations in their blood (Pb-B) were 16.55 +/- 11.53 micrograms/100 ml (range 1.5 to 50.2 micrograms/100 ml). The subjects were divided into three groups according to Pb-B (in microgram/100 ml): group A, Pb-B < or = 10 (n = 22); group B, 10 < Pb-B < or = 20 (n = 30); group C, Pb-B > 20 (n = 18). The mean +/- S.D. in each group was 5.57 +/- 2.53, 15.02 +/- 2.75, and 32.52 +/- 9.49 micrograms/100 ml, respectively. Pb in plasma was 0.011 +/- 0.010, 0.017 +/- 0.033, and 0.021 +/- 0.021 microgram/liter, and Pb in the RBC was 0.281 +/- 0.246, 0.701 +/- 0.325, and 1.626 +/- 0.861 micrograms/g Hb, respectively. In addition to Pb concentration, the concentrations of 34 elements in the plasma or in the RBC were determined. Se concentrations in RBC in each group were 0.618 +/- 0.139, 0.670 +/- 0.207, and 0.728 +/- 0.200 microgram/g Hb, and the mean values were significantly different between groups A and C (p < 0.05). For Se concentration in plasma, the mean +/- S.D. in each group was 0.132 +/- 0.035, 0.130 +/- 0.031, and 0.126 +/- 0.021 microgram/ml, respectively, and there was no significant difference between groups. On the other hand, when the activities of total SOD, Mn-SOD, Cu, Zn-SOD, and catalase in the plasma and the activities of GSH-Px both in the plasma and in the RBC were assayed, some differences were found. The activities in GSH-Px in RBC were 17.19 +/- 5.03, 17.59 +/- 3.95, and 15.25 +/- 3.18 mumol/g Hb/min, and those in plasma were 0.069 +/- 0.032, 0.081 +/- 0.023, and 0.080 +/- 0.028 mumol/ml/min. In group C, GSH-Px activity was lower in the RBC and higher in the plasma than those in group A, and it was observed that the Se concentration was higher in RBC, and that there was no remarkable change in the plasma. Catalase activity in group C was 3.58 +/- 0.81 mgH2O2/ml/30 min, which was significantly higher than that in group A (2.81 +/- 0.90 mgH2O2/ml/30 min). Further investigation is necessary in order to explain the above results. The regular indices used for evaluating lead exposure, showed significant correlations with Pb-B: r = -0.786 vs delta-Aminolevulinic acid (ALA) dehydratase activity in blood, r = 0.927 vs. inhibition rate, and r = 0.339 vs. ALA in urine.

Aminolevulinic Acid↗
PubMed1996

[Role of essential trace elements on sexual function and its disorder].

Recent reports on the role of trace elements in human reproductive potential were summarized. Zn has been known as an important element in male sexual function, and works as key element in several seminal reactions. Se, Fe, and Cu are also essential for male fertility. Intracellular Ca play an important role in many reactions such as sperm motility, acrosome reaction, capacitation, etc. Our data on 13 elements in semen samples from 110 male patients of infertile couples were also described; 1) element concentrations were Na > P, K > Ca > Zn > Mg > Fe > Cu > Se >> Sn, Ni, Co, Cd, 2) Correlation between Se concentration and sperm concentration (r = 0.589, p < 0.001), where Se contents in spermatozoa showed very high correlation (r = 0.886), 3) Zn in semen were not correlated with sperm parameters, but were correlated with concentrations of Mg (r = 0.903), K (r = 0.810), and Ca (r = 0.715). There has been few information on the role of trace elements in female sexual function.

Animals↗
PubMed1996

[The importance of serum lipid level for restenosis following initial successful percutaneous transluminal coronary angioplasty in patients with unstable angina].

Serum lipids were investigated as a risk factor for restenosis following initial percutaneous transluminal coronary angioplasty (PTCA) for unstable angina (Braunwald III-B2). Follow-up angiography was used to classify 41 patients who received successful emergency PTCA into two groups: 21 patients with and 20 without restenosis. The clinical factors (age, sex), lesion characteristics and extent of coronary narrowing before and after PTCA were similar in the two groups. In the group without restenosis, the serum cholesterol level was significantly reduced from 225 +/- 48 (before PTCA) to 188 +/- 34 mg/dl (at the follow-up PTCA; p < 0.01), but in the group with restenosis serum cholesterol level showed no difference between before PTCA (211 +/- 42) and at the follow-up (201 +/- 32 mg/dl). The levels of triglycerides and high-density lipoprotein (HDL) cholesterol were not significantly different between before PTCA and at the follow-up in both groups. The restenosis rate in patients with serum cholesterol level reduced by 30 mg/dl or more at the follow-up after PTCA was significantly lower (three of 15 patients, 20%) compared with the restenosis rate in patients with serum cholesterol level lowered by less than 30 mg/dl (18 of 26 patients, 69%; p < 0.01). Moreover, the restenosis rate in patients with serum cholesterol level below 180 mg/dl at the follow-up angiography was significantly lower (six of 19 patients, 32%) compared with patients with serum cholesterol levels above 180 mg/dl (15 of 22 patients, 68%; p < 0.05). A high level of serum cholesterol may be a predictor of restenosis following PTCA in patients with unstable angina.

Angina, Unstable↗