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Biomedical subjects

T Yabe

Publications and source records attributed to T Yabe.

At least 109 records · Page 6Linked to original sources
PubMed1995

[Tympanosclerosis--clinical and pathological investigation].

Fifty-nine cases of tympanosclerosis were investigated clinically and pathologically, and the following results were obtained: 1) The male to female ratio was about 1:1.8 2) Calcification in the tympanic membrane was most common in the upper quadrants of the pars tensa, and never seen in the pars flaccida. 3) Calcification in the middle ear cavity was most common around the malleus. 4) Chronic otitis media was the most common complication of tympanosclerosis. 5) Preoperative audiometry revealed a stiffness curve with elevated bone conduction thresholds. 6) 54% of the patient had chronic otitis media in the contralateral ear. 7) Microscopic examination revealed calcification in the submucosa of the middle ear. 8) Postoperative hearing was improved in 49 ears (79.7%). Because there was no difference in the average postoperative hearing gain after type I and type III tympanoplasty, type III tympanoplasty is recommended to remove sclerotic masses completely.

Adolescent↗
PubMed1995

[Prognosis of patients with triple vessel disease and old myocardial infarction: relationship to the number of total coronary occlusions].

Patients with myocardial infarction (MI) and triple vessel coronary disease generally have poor prognoses. However, it is not known whether there are particular angiographic variables associated with the poor prognosis in MI patients with triple vessel disease. The angiographic variables for poor prognosis were investigated in 43 MI patients with triple vessel disease (32 men and 11 women, mean age 63 +/- 9 years) who were followed medically for a mean of 32 +/- 28 months. There were 13 cardiac deaths (30%) and 10 late-coronary artery bypass grafting (23%). Twenty patients were alive and well. The patients who died of cardiac causes had lower ejection fractions (42 +/- 18% vs 49 +/- 15%, p < 0.05), a higher prevalence of two vessel occlusion (77% vs 40%, p < 0.05), and a higher prevalence of coronary occlusion opposite the MI site (69% vs 25%, p < 0.01) when compared to survivors, although there were no significant differences in age, MI sites, or the prevalence of occlusion in the infarct-related artery. Multivariate analysis with the Cox proportional hazards model revealed that coronary occlusion opposite the MI site (hazards ratio 16.36) and an age of > or = 65 years (4.46) indicated a significantly high ratio. The hazard ratio of the ejection fraction and two vessel coronary occlusion were not significant. The poor prognosis of MI patients with triple vessel coronary disease may be related to impaired left ventricular function and to coronary occlusion opposite the MI site and greater age. This may have important clinical implications in the initial decision for interventional therapy.

Adult↗
PubMed1995

Fifteen-year statistics and observation of facial bone fracture.

During the past 15 years, we encountered 1051 facial fractures. The number of patients with facial fractures accounted for 0.76% of the over all outpatients at the ENT clinic of Osaka City University Hospital. There were 496 nasal bone fractures, 111 maxillary fractures, 167 zygomatic fractures, 122 mandibular fractures, and 130 orbital fractures. These types of fractures accounted for 47.2%, 10.6%, 15.9%, 11.6%, and 12.4% of the over or facial fractures, respectively. The ratio of men to women was nearly three to one, with 794 men and 257 women. Among nasal fractures, injury causes were ranked in the order of fighting, sports, and traffic accident. Among facial fractures, injury causes were ranked in the order of the traffic accident, fighting, and falling down.

Adolescent↗
PubMed1995

Phenotypical and functional analyses of natural killer cells from low NK activity individuals among healthy and patient populations.

We investigated the deficiency of natural killer (NK) activity by contrasting healthy individuals with patients. Human NK activities of 125 individuals consisting of 68 healthy donors and 57 patients (36 autoimmune disease and 21 cancer patients) were measured by Eu-DTPA release assay in which the target cells were labeled by nonradioactive materials-Eu-DTPA, and they were phenotypically analyzed with three-color flow cytometry. Furthermore, a part of these donors was functionally studied on NK cells sorted out from PBL. 23.3% of healthy donors and approximately 70% of patients had low NK activity (LNK). In these healthy LNK and patient LNK, the population of CD3-CD16+CD56+ subset in PBL was significantly lower than that of the same subset in healthy individuals with high and medium NK activity (HMNK). The cytotoxicity of CD3-CD16+CD56+ cells sorted out from PBL in healthy LNK and patient LNK were approximately the same with or higher than that in healthy HMNK. No differences were found either in the expression of CD2 and LFA-1 antigens on the CD3-CD56+ NK cells or in the amount of granulous proteins such as perforin and granzyme A in these cells among healthy HMNK, healthy LNK and patient LNK. These results suggested that low NK activity of healthy LNK and patient LNK was more reflected by the diminution of the population of CD3-CD16+CD56+ subset in PBL rather than the functional defects of NK cells. A phenotypical and functional study on healthy LNK has not been reported extensively, and we found several differences between healthy LNK and patient LNK in this study. By stimulation with IL-2, the cytotoxicity of healthy LNK increased more rapidly than that of patient LNK, and at high effector:target cell ratio (> or = 40) it was significantly higher than that of patient LNK. The population of CD3+CD16+/CD56+ subset in PBL of healthy LNK was higher than that of patient LNK, but on the other hand it was about the same as that of healthy HMNK.

Adult↗
PubMed1994

Absence of hemodynamic tolerance to nicorandil in patients with severe congestive heart failure.

To evaluate whether hemodynamic tolerance develops to nicorandil, a nitrate and potassium channel opener, 14 patients with chronic heart failure (CHF) were treated with nicorandil and 11 were treated with nitroglycerin (GTN). Doses of GTN or nicorandil were titrated to achieve a > or = 20% reduction in pulmonary capillary wedge pressure (PCWP) within 1 hour, and the infusion was maintained at a constant rate for 24 hours. Both groups of patients had comparable hemodynamic parameters before drug infusions were started. The fall in PCWP was identical after 1 hour infusion of either GTN or nicorandil. In the GTN group, PCWP was not significantly different from the baseline value at 12 hours; however, in the nicorandil group, PCWP remained significantly lower than the preinfusion value for 24 hours. During the study period changes in plasma atrial natriuretic peptide (ANP) concentrations paralleled and correlated with changes in PCWP (r = 0.84, p < 0.001). These findings indicate that CHF patients develop hemodynamic tolerance to GTN within 12 hours of continuous infusion, but not to nicorandil, which remained hemodynamically effective during the 24-hour period of infusion. Furthermore, plasma ANP concentration may be a useful noninvasive index of hemodynamic tolerance during GTN or nicorandil therapy in patients with CHF.

Adult↗
PubMed1994

Cloning of the Saccharomyces cerevisiae gene whose overexpression overcomes the effects of HM-1 killer toxin, which inhibits beta-glucan synthesis.

A gene whose overexpression can endow Saccharomyces cerevisiae cells with resistance to HM-1 killer toxin was cloned from an S. cerevisiae genomic library. This gene, designated HKR1 (Hansenula mrakii killer toxin-resistant gene 1), contains a 5.4-kb open reading frame. The predicted amino acid sequence of the protein specified by HKR1 indicates that the protein consists of 1,802 amino acids and is very rich in serine and threonine, which could serve as O-glycosylation sites. The protein also contains two hydrophobic domains at the N-terminal end and in the C-terminal half, which could function as a signal peptide and transmembrane domain, respectively. Hkr1p is found to contain an EF hand motif of the calcium-binding consensus sequence in the C-terminal cytoplasmic domain. Thus, Hkr1p is expected to be a calcium-binding, glycosylated type I membrane protein. Southern and Northern (RNA) analyses demonstrated that there is a single copy of the HKR1 gene in the S. cerevisiae genome, and the transcriptional level of HKR1 is extremely low. Gene disruption followed by tetrad analysis showed that HKR1 is an essential gene. Overexpression of the truncated HKR1 encoding the C-terminal half of Hkr1p made the cells more resistant to HM-1 killer toxin than the full-length HKR1 did, demonstrating that the C-terminal half of Hkr1p is essential for overcoming the effect of HM-1 killer toxin. Furthermore, overexpression of HKR1 increased the beta-glucan content in the cell wall without affecting in vitro beta-glucan synthase activity, suggesting that HKR1 regulates beta-glucan synthesis in vivo.

Amino Acid Sequence↗
PubMed1994

Detection of myocardial ischemia by 31P magnetic resonance spectroscopy during handgrip exercise.

BACKGROUND: The metabolic changes of myocardial ischemia in patients with coronary artery disease assessed by 31P magnetic resonance spectroscopy (MRS) have been reported previously. A significant decrease in the ratio of phosphocreatine (PCr) to ATP during handgrip exercise in a group of patients with severe coronary artery disease has been demonstrated. However, there are no reports at present that directly compare cardiac 31P MRS data with exercise 201Tl myocardial scintigraphy, now established as one of the most important clinical methods to assess myocardial ischemia. The purpose of this study was to investigate whether 31P MRS with handgrip exercise testing is able to detect myocardial ischemia, demonstrated by exercise 201Tl scintigraphy. METHODS AND RESULTS: Twenty-seven patients with severe stenosis of the left anterior descending coronary artery (> or = 75%) and 11 normal control subjects composed the present study. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+]) who demonstrated redistribution at the late image and a fixed 201Tl defect group (RD[-]). While lying supine within the magnet, subjects performed handgrip exercise at 30% of maximal force once in every two cardiac cycles. 31P MR spectra were collected before and during handgrip exercise. Data were corrected for the saturation factor. ANOVA revealed significant differences among the three groups with respect to the mean +/- SD PCr/ATP ratio at rest (control, 1.85 +/- 0.28 > RD(+), 1.60 +/- 0.19 > RD(-), 1.24 +/- 0.30; P < .05). The PCr/ATP ratio decreased significantly from 1.60 +/- 0.19 at rest to 0.96 +/- 0.28 during exercise (P < .001) in the RD(+) group (n = 15). However, in the RD(-) group (n = 12), the ratio did not change significantly during handgrip exercise (1.24 +/- 0.30 at rest versus 1.19 +/- 0.28 during exercise). Similarly, the ratio did not change in the control group (n = 11) (1.85 +/- 0.28 at rest versus 1.90 +/- 0.23 during exercise). CONCLUSIONS: Contrary to normal subjects or patients with fixed thallium defects, the PCr/ATP ratio was significantly altered by exercise in patients with reversible thallium defects. These results suggest that 31P MRS with handgrip exercise testing is a sensitive method for detecting myocardial ischemia.

Adenosine Triphosphate↗
PubMed1994

Sound evaluation of partially implantable piezoelectric middle ear implant: comparative study of frequency responses.

Two comparative studies were performed in six subjects using partially implantable middle ear implants (MEI). The sound quality was evaluated by speech discrimination tests and sound evaluation tests. In the first experiment, the performance of the output transducer of the MEI and an ear phone of a conventional hearing aid was compared. The MEI showed better results than the hearing aid in both the speech discrimination tests and sound quality rating. In the second experiment, four kinds of frequency responses for the external component of the MEI were compared. Sound quality evaluation in a wide frequency response with a peak at 4000 Hz were superior to those with the frequency response of the present MEI model. In conclusion, improvement of the external component in the frequency response can provide better performance of the MEI.

Audiometry↗
PubMed1993

Genomic structure of NKG5, a human NK and T cell-specific activation gene.

We reported previously the isolation of a cDNA clone, designated NKG5, encoding a secreted protein that is expressed only in natural killer and T cells and is strongly upregulated upon cell activation. In this report we have isolated the NKG5 gene from a human placental genomic library and sequenced the gene and two kilobases of 5'-flanking DNA. Comparison with the cDNA sequence reveals that the NKG5 gene consists of five exons and four introns. Intron 1 contains a DNA segment that was reported to occur as an exon in 519, a closely related cDNA clone that was isolated from a T-cell library. This result indicates that NKG5 and 519 are alternative splicing products of a single gene. The 5'-flanking region of the NKG5 gene was analyzed for homology with the promoter regions of cytokines and other activation-induced genes showing lymphocyte-specific expression. Several segments displaying sequence similarity were identified. We also identified numerous sequence elements that have strong similarity to known binding sites for transcriptional regulatory proteins including T cell-specific and activation-specific regulatory factors. These findings are consistent with the cell-specific expression and the tight regulatory control that is observed for the NKG5 gene.

Alternative Splicing↗
PubMed1993

A multigene family on human chromosome 12 encodes natural killer-cell lectins.

We previously isolated a series of cDNA clones designated NKG2-A, B, C, and D from a human natural killer (NK) cell library. These transcripts encode a family of type II integral membrane proteins having an extracellular Ca(2+)-dependent lectin domain. The predicted peptides share structural similarities and amino acid sequence similarity with known receptor molecules. In this report, the genomic organization and mRNA expression of each of the genes were studied by using transcript-specific probes. Southern blot experiments reveal that the probes cross-hybridize with a maximum of five genes at high stringency. By probing a Southern blot prepared from a series of hamster/human hybrid somatic cell lines, we demonstrated that all of the hybridizing fragments occur on human chromosome 12. No gene rearrangement and little restriction fragment length polymorphism (RFLP) was observed with these probes. mRNA expression of the NKG2 genes occurred in NK cells and some T cells but not in other hematopoietic cell types or in other tissues tested. Each of the transcripts occurred in all three of the NK cell lines tested: however, the genes were differentially regulated in T cells. NKG2-D was expressed in nine of fourteen T-cell clones or lines in the panel, whereas NKG2-A/B was expressed in three and NKG2-C was expressed in only one. Expression of each of the transcripts was upregulated following T-cell growth factor (TCGF)-induced activation of a cloned NK cell. The limited distribution of these proteins and their sequence similarity with known receptor molecules suggest that they may function as receptors on human NK cells.

Alternative Splicing↗
PubMed1993

Medial vestibular nucleus in the guinea-pig: histaminergic receptors. II. An in vivo study.

In a companion paper (Serafin et al. 1992) we have demonstrated in vitro that histamine depolarizes three previously described medial vestibular nucleus neuron (MVNn) types (Serafin et al. 1991a, b). It has also been shown that this effect was exclusively mediated through postsynaptic H2 receptors. All the same, the eventual contribution of presynaptic H3 receptors to the physiological response of the MVNn to histamine remained an open question since, during the slicing procedure, any histaminergic axons projecting to the vestibular nuclei would have been interrupted. This rendered our study of H3-mediated effects of histamine difficult. Hence, in the present in vivo study our aim was three-fold: (1) to investigate the presence of H3 receptors at the vestibular nuclei level; (2) to evaluate the functional importance of MVNn H2 receptors; and (3) to explore whether H3 ligands, when injected intraperitoneally (i.p.), could modulate dynamic vestibular functions. In order to address the first two questions, we investigated postural changes induced by perfusion of the guinea-pig's vestibular nuclear complex with specific ligands of the H2 and H3 receptors. Our data extend the conclusions of our in vitro study and suggest that lateral vestibular nuclei neurons and the MVNn are endowed with both H2 and H3 receptors. Our results indicate furthermore that histamine can modulate, quite effectively, static vestibular reflexes. Finally, the present study demonstrates that i.p. injection of thioperamide, an H3 antagonist, induces a significant decrease in the horizontal vestibular-ocular reflex gain and, by contrast to most of the clinically used antihistaminics, has no detrimental effect on the alertness level. Our results may thus lead to clinical testing and use of H3 antagonists as antivertigo or anti motion-sickness drugs.

Animals↗
PubMed1993

Medial vestibular nucleus in the guinea-pig: apamin-induced rhythmic burst firing--an in vitro and in vivo study.

In a previous in vitro study, we have shown that guinea-pig medial vestibular nucleus neurons (MVNn) can be grouped into two main cell types based on their intrinsic membrane properties. Subsequent in vivo and in vitro studies demonstrated that these neurons are endowed with N-methyl-D-aspartate (NMDA) receptors and that NMDA induces rhythmic bursts in B MVNn. We now report the occurrence of rhythmic bursts in B MVNn (and in the subclass of B+LTS MVNn) which are induced by long-lasting perfusion of either apamin, a selective blocker of one type of Ca(2+)-dependent K+ conductance (SK channels), or by a high Mg2+/low Ca2+ artificial cerebrospinal fluid. Apamin-induced bursts were studied in vitro in brainstem slices, and in vivo in the alert unrestrained guinea-pig. In vitro, intracellular recordings demonstrated that the frequency of the bursts was voltage dependent. These bursts were insensitive to D-2-amino-5-phosphopentanoic acid but could be abolished by tetrodotoxin or blocked by the bath application of 20-50 microM of ouabain, a blocker of the sodium pump. In the in vivo preparation, unilateral infusion of apamin into the vestibular nuclei induced oscillatory head and eye movements. Our data show that the blockade of a Ca(2+)-activated K+ conductance may switch, in vitro and probably in vivo, the B MVn firing pattern from a regular to a bursting firing pattern.

2-Amino-5-phosphonovalerate↗
PubMed1993

Evaluation of left ventricular mass: comparison of ultrafast computed tomography, magnetic resonance imaging, and contrast left ventriculography.

We measured and compared left ventricular mass in 20 patients by ultrafast computed tomography (UFCT), magnetic resonance imaging (MRI), and contrast left ventriculography (LVG). Left ventricular mass was calculated by UFCT and MRI in two ways: (1) excluding papillary muscles and trabeculae (LV mass), and (2) including papillary muscles and trabeculae (LV mass + PM&T) by Simpson's method. Left ventricular mass excluding papillary muscles and trabeculae (LV mass) in LVG was calculated by Rackley's method by biplane angiocardiography. LV mass was significantly larger in LVG than in MRI and UFCT (p < 0.01). Although LV mass was significantly larger in MRI than in UFCT (p < 0.01), there was no significant difference in LV mass + PM&T between UFCT and MRI. Interobserver and intraobserver variability showed good correlation of coefficient in both UFCT and MRI. We therefore conclude that left ventricular mass is best measured by including papillary muscles and trabeculae by Simpson's method in UFCT or MRI.

Adult↗
PubMed1993

Characterization of a novel gene (NKG7) on human chromosome 19 that is expressed in natural killer cells and T cells.

NKG7 is a cDNA clone generated from a human NK-cell clone. The DNA and predicted aa sequence of NKG7 is not homologous with any previously reported genes or peptides. NKG7 mRNA is expressed in activated T cells and in A-LAK cells isolated from the peripheral blood of normal individuals, and in normal human kidney, liver, lung and pancreas. Furthermore, NKG7 mRNA is expressed at high levels in TCR gamma delta-expressing CTL clones, and in some TCR alpha beta-expressing CTL clones (both CD4+ and CD8+), but is not expressed in other TCR alpha beta-expressing CTL clones and in cell lines representing B cells, monocytes, and myeloid cells. NKG7 mRNA is not expressed in normal human brain, heart, or skeletal muscle. Southern hybridization of NKG7 suggests that NKG7 is a single-copy gene localized to chromosome 19. A hydropathicity profile of the predicted 148 aa polypeptide indicates that NKG7 is a type-I integral membrane protein with a 38-aa extracellular domain and a 61-aa cytoplasmic domain. These results indicate that the NKG7 gene encodes a novel cell surface protein expressed in several cell types, including NK cells and T cells.

Amino Acid Sequence↗