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Biomedical subjects

Y Ishibashi

Publications and source records attributed to Y Ishibashi.

At least 19 recordsLinked to original sources
PubMed1995

Long amyloid beta-protein secreted from wild-type human neuroblastoma IMR-32 cells.

The 39- to 43-amino acid amyloid beta-protein (A beta) is deposited as amyloid in Alzheimer's disease. Recent studies have suggested that short A beta (A beta 39 or A beta 40) and long A beta (A beta 42 or A beta 43) play different roles in Alzheimer-type pathology. However, little attempt has been made to investigate the cellular mechanisms underlying the generation of short and long A beta individually. In the present report, we first measured the amount of short and long A beta that are secreted from wild-type human and rodent cells with neuron- or glia-like properties using highly sensitive sandwich-ELISAs that discriminate long A beta from short A beta. The results showed that long A beta secreted by all cells constitutes approximately 10% of the total A beta. To identify the molecular species of long A beta, we next isolated the A beta species secreted from human neuroblastoma IMR-32 cells by affinity chromatography, gel-filtration HPLC, and reverse-phase HPLC. Mass spectrometric analysis demonstrated unequivocally that IMR-32 cells produce A beta 1-42 together with A beta 1-37, A beta 1-38, A beta 1-39, and most predominantly, A beta 1-40. Finally, to investigate the cellular mechanisms that generate A beta 1-42, we studied the effects of brefeldin A and monensin on the production of A beta 1-40 and A beta 1-42 in IMR-32 cells. These reagents reduced the production of both A beta 1-40 and A beta 1-42 simultaneously in a concentration-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloid beta-Peptides↗
PubMed1995

Involvement of cholinergic systems in the deficit of place learning in Morris water maze task induced by baclofen in rats.

Effects of oxotremorine on the deficit of place learning in the Morris water maze task induced by baclofen and scopolamine were examined to determine the involvement of brain cholinergic systems in the deficit of learning induced by baclofen. Rats were given 4 training trials per day with the submerged platform at a fixed location in the maze for 4 days. On day 4, rats were required to swim in the pool without the platform after the 4th training trial (probe test). Baclofen as well as scopolamine dose-dependently increased the escape latency in the training trials. In the probe test, baclofen as well as scopolamine dose-dependently reduced the duration in the quadrant where the platform had been originally located. Increased latency in the training trials and reduced duration in the probe test induced by scopolamine were dose-dependently attenuated by oxotremorine. Increased latency and reduced duration in the baclofen-treated rats were improved by oxotremorine as well as 2-hydroxysaclofen. Baclofen but not scopolamine induced motor incoordination in the rotarod test. Oxotremorine failed to improve motor incoordination induced by baclofen. These results suggest that cholinergic systems may be involved in the deficit of place learning induced by baclofen, and that the ameliorative effects of oxotremorine may not be due to improvement of motor incoordination.

Animals↗
PubMed1995

Muscimol induces state-dependent learning in Morris water maze task in rats.

Effects of muscimol on the place learning in Morris water maze task were investigated in rats. Rats were given 4 training trials per day with the submerged platform at a fixed location in the maze for 4 days. On day 4, rats were required to swim in the pool without the platform after 4 training trials (probe test). Compared to the saline-treated rats, the rats treated with muscimol on day 1-4 showed no modifications of place learning in the training trials and the probe test. However, in the rats treated with muscimol on day 1-3 and treated with saline on day 4, there was increased latency to reach the platform and reduced duration in the quadrant where the platform had been located on day 4. The increased latency in the training trials and reduced duration in the probe test on day 4 was blocked by bicuculline, when bicuculline and muscimol were co-administered on day 1-3, and saline was injected on day 4. Moreover, in the rats treated with muscimol on day 1-3, co-administration of bicuculline and muscimol on day 4 blocked place learning: increased latency in the training trials and reduced duration in the probe test was observed. These results suggest that muscimol induces state-dependent learning (SDL) in Morris water maze task, and that muscimol-induced SDL is mediated by GABAA receptors.

Animals↗
PubMed1995

Effect of knee flexion on the in situ force distribution in the human anterior cruciate ligament.

This study was conducted to evaluate the effect of applied load on the magnitude, direction, and point of tibial intersection of the in situ forces of the anteromedial (AM) and posterolateral (PL) bands of the human anterior cruciate ligament (ACL) at 30 degrees and 90 degrees of knee flexion. An Instron was used to apply a 100 N anterior shear force to 11 human cadaver knees, 6 at 30 degrees of knee flexion and 5 at 90 degrees of knee flexion. A Universal Force Sensor (UFS) recorded the resultant 6 degree-of freedom (DOF) forces/moments. Each specimen then underwent serial removal of the AM and PL bands. With the knee limited to 1 DOF (anteroposterior), tests were performed before and after each structure was removed. Because the path was identical in each test, the principle of superposition was applied. Thus, the difference between the resultant forces could be attributed to the force carried by the structure just removed. The magnitudes of force in the ACL at 30 degrees and 90 degrees of knee flexion were 114.1 +/- 7.4 N and 90.8 +/- 8.3 N, respectively (P < 0.05). At 30 degrees, the AM and PL bundles carried 95% and 4% of the total ACL force, respectively. At 90 degrees, the AM and PL bands carried 85% and 13%, respectively (P < 0.05). The direction of the in situ force in the whole ACL as well as its two bands correlated with the anatomic orientation of the ligament.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

An immunohistochemical and ultrastructural study of vasomotor nerves in the microvasculature of human dental pulp.

Immunohistochemical methods for S-100 protein and neurone-specific enolase showed two types of nerve endings around the pulp microvasculature: the free endings, which comprise the major neural component and are distributed in all types of microvessel such as arterioles, venules and capillaries; and the varicose endings. The varicose ending was a less frequent, minor component observed only in the arterioles. Both immunohistochemical and ultrastructural observations confirmed that the varicose endings were the terminal axons of efferent vasomotor nerves. Further extensive ultrastructural examinations on the vasomotor nerves added the following new findings to our previous reports. Vasomotor nerves sometimes ramified into more than two terminal axons around arterioles, and most of these ramified axons ended in the adventitia-media junction of the arteriolar wall; however, nerve endings occasionally penetrated into the media. These findings suggest an intimate structural association between vasomotor nerves and arterioles in regulating the arteriolar microcirculation in human dental pulp by stimulating smooth-muscle cells not only of the outermost but also of the inner layers. Furthermore, the deep penetration of terminal axons into the arteriolar wall seems to provide effective regulation of pulpal blood flow under physiological and pathological conditions.

Adult↗
PubMed1995

The proliferative activity in oral epithelial dysplasia analyzed by proliferating cell nuclear antigen immunostaining and argyrophilic nucleolar organizer region staining.

The proliferative activity of leukoplakia without dysplastic change (LP), epithelial dysplasia (ED), and squamous cell carcinoma (SCC) in the oral mucosa was examined by means of proliferating cell nuclear antigen (PCNA) immunostaining, silver-binding argyrophilic nucleolar organizer region (AgNOR) staining, and the frequency of mitotic figures. Significant differences in the labeling index of PCNA immunostaining (PI) and mitotic index (MI) were noted between LP and ED and between ED and SCC. The mean numbers of AgNORs (AI) significantly differed between ED and SCC. There was a significant positive correlation between PI and MI in samples of ED. However, there was no significant correlation between AI and other indexes. The number and the distribution of PCNA-positive cells in ED varied among samples. Five samples with higher PI and MI indexes than the mean values were selected from those of dysplasia based on the correlation between PI and MI. Their histological features symptomatic of oral ED as defined by the World Health Organization (WHO) Collaborating Centre in 1978, were investigated and compared with 10 samples with lower indexes. Histological findings, such as "loss of polarity of the basal cells," "an increased nuclear-cytoplasmic ratio," "cellular pleomorphism," and "enlarged nucleoli," were significant histological features of these five samples. This study showed that the four histological components described previously and the increased number of mitotic figures used as the index of proliferating activity were the main histological components related to severe ED of oral mucosa. They will provide a useful means of deciding the histopathological grade of oral ED.

Adult↗
PubMed1995

So-called mixed tumor of the skin on the wrist: an immunohistochemical study.

A case of so-called mixed tumor of the skin arising on the wrist was reported. Immunohistochemical staining of keratins of several molecular weights (AE1/AE3, RCK102, NCL-5D3 and 35 beta H11), carcinoembryonic antigen (CEA), S-100 protein, and desmin was performed. AE1/AE3 and RCK102 were positive in all the tumor cells; CEA, NCL-5D3 and 35 beta H11 were positive mainly in luminal cells of the tubuloalveolar structures. S-100 protein was positive in peripheral cells of the tubular lumina and in scattered cells in the mucous stroma. Desmin was negative in all the tumor cells. Immunohistochemical findings lent further support to the hypothesis that so-called mixed tumor of the skin differentiates into the secretory and ductal portions of the sweat gland.

Adenoma, Pleomorphic↗
PubMed1995

Phasic right coronary blood flow in a patient with right ventricular hypertension using transesophageal Doppler echocardiography.

Although phasic right coronary artery blood flow in right ventricular hypertension has been studied in animals, reports on human subjects are not available. We observed right coronary artery blood flow before and after operation in a patient with right ventricular hypertension secondary to atrial septal defect using transesophageal Doppler echocardiography. Prior to surgery, blood flow was predominantly diastolic in both right and left coronary arteries. Reversal of right ventricular hypertension after surgery resulted in a change in the pattern of right coronary flow, with doubling of flow during systole.

Coronary Circulation↗
PubMed1995

DNA fingerprinting of animal genomes by CA-repeat primed polymerase chain reaction.

CA-repeat primed polymerase chain reaction (CAP-PCR), using degenerate primers which anneal at the ends of (CA)n sequences in eukaryotic genomes, was attempted to assess its potential to monitor the genomic polymorphisms in various animals. Three mammalian, three avian, one fish and one insect species were examined and all showed primer-specific DNA fingerprints by CAP-PCR. Polymorphic bands observed in a laboratory-bred vole family were segregated in Mendelian manner. The present CAP-PCR DNA fingerprinting therefore is a simple and useful method for examining genomic variations in most animals without prerequisite knowledge of DNA sequences.

Animals↗
PubMed1995

[Long-term results of Bentall and modified Bentall procedure in aortic root replacement].

Between 1976 and 1994, sixteen patients who had annulo-aortic ectasia required aortic root replacements. Ten patients had annulo-aortic ectasia and 6 patients had aortic dissections. The operative techniques included Bentall procedure in 6, Cabrol procedure in 3 and Carrel patch procedure in 7. No hospital death was noted, although there were three major late complications and two of them died. First patient having Bentall procedure died from acute myocardial infarction because of the compressed left coronary artery by the wrapping aneurysmal wall. Second patient having Bentall procedure had enlargement of residual false lumen. Third patient having Cabrol procedure developed false aneurysm at the ostial anastomosis and died of cerebral haemorrhage. In contrast, no late complication has been noted in patients having Carrel patch procedure. Although further long-term follow-up is required, our experience suggests that Carrel patch procedure has less late complication.

Adult↗
PubMed1995

[A nation-wide survey on the occurrence of amoebic keratitis in Japan].

Acanthamoeba keratitis in Japan was first reported by Ishibashi in 1988. Since then, the incidence of Acanthamoeba keratitis has gradually increased. We retrospectively analyzed 39 cases, 42 eyes, of amoebic keratitis reported in Japan from 1988 to September 1993. Of the 39 patients, 35 (89.7%) wore contact lenses, 32 (82.1%) soft contact lenses, and 3 (7.7%) hard contact lenses, and 4 (10.3%) did not wear contact lenses. Of the 4 patients without contact lenses, 3 had a history of trauma. Acanthamoeba keratitis is often difficult to diagnose. Twenty-four cases were misdiagnosed as herpetic keratitis. Early diagnosis and adequate therapy are important.

Acanthamoeba Keratitis↗
PubMed1995

[Emergency coronary bypass grafting for failed percutaneous transluminal coronary angioplasty].

From January 1992 through September 1993, 545 patients underwent PTCA in Asahikawa City Hospital. 6 patients (1.1%) required emergency CABG. Perfusion catheter was placed in three patients. This catheter allowed for immediate and temporary reperfusion of blood to the ischemic myocardial tissue. And it provided us with time and a patient in stable condition. This technique reduce PMI, morbidity, and mortality in emergency CABG after failed PTCA.

Aged↗
PubMed1994

APP717 missense mutation affects the ratio of amyloid beta protein species (A beta 1-42/43 and a beta 1-40) in familial Alzheimer's disease brain.

We have biochemically purified A beta from brains of two unrelated familial Alzheimer's disease (FAD) pedigrees with the APP717 mutation (Val-->Ile) and from two sporadic Alzheimer's disease (AD) brains and characterized them by means of mass spectrometry and enzyme-linked immunosorbent assay. We observed two types of amyloid beta protein (A beta), the short-tail form (A beta 1-40) and the long-tail form (A beta 1-42/43), in sporadic AD and FAD brains, and found that the ratio of the long-tail form of A beta (A beta 1-42/43) to total A beta was increased in FAD brains. These in vivo results were confirmed in vitro using cultured cells transfected with three kinds of APP cDNAs bearing the APP717 mutations (Val-->Ile, Gly, or Phe). Taken together with the hypothesis that A beta 1-42/43 functions as a "seed" that increases the kinetics of amyloid fibril formation (Jarrett, J. T., and Lansbury, P. T., Jr. (1993) Cell 73, 1055-1058), we conclude that the APP717 missense mutation does not create new A beta species but promotes the increased accumulation of A beta 1-42/43 in the brain, which results in the enhancement of amyloid fibril formation from soluble A beta. These findings provide a causal relationship between this FAD genotype and the pathological phenotype of A beta deposition and senile plaque formation.

Adult↗
PubMed1994

Effects of supine and lateral recumbent positions on pulmonary venous flow in healthy subjects evaluated by transesophageal Doppler echocardiography.

OBJECTIVES: This study attempted to evaluate the effects of supine and lateral recumbent positions on pulmonary venous flow by transesophageal Doppler echocardiography in healthy subjects. BACKGROUND: Although transesophageal echocardiographic examination is usually performed with the patient lying in the left lateral decubitus or supine position, little attention has been paid to the effects of these positions on pulmonary venous flow. METHODS: We performed pulsed Doppler transesophageal echocardiography of the left and right pulmonary veins in 16 normal subjects as they lay in the left and right lateral decubitus and supine positions. RESULTS: Data are reported as mean value +/- SD. Adequate recordings were obtained in 12 subjects (75%). In the left pulmonary vein, peak systolic velocity and time-velocity integral of systolic flow increased significantly in the left compared with the right lateral decubitus position (56 +/- 12 vs. 44 +/- 13 cm/s, p < 0.05, and 15 +/- 4 vs. 9 +/- 4 cm, p < 0.05, respectively). In the right pulmonary vein, peak systolic velocity and time-velocity integral of systolic flow decreased significantly in the left compared with the right lateral decubitus position (38 +/- 10 vs. 48 +/- 9 cm/s, p < 0.05, and 9 +/- 2 vs. 12 +/- 2 cm, p < 0.05, respectively). There were no significant differences between positions in peak diastolic flow velocity, time-velocity integral of diastolic flow or peak velocity of flow reversal at atrial contraction. CONCLUSIONS: Pulmonary venous systolic peak velocities and time-velocity integrals of systolic flow increase when the pulmonary venous recording is from the recumbent subject's lower side. Therefore, the effects of position should be considered in evaluating left ventricular diastolic function by transesophageal Doppler echocardiography.

Adult↗
PubMed1994

Bordetella pertussis filamentous hemagglutinin interacts with a leukocyte signal transduction complex and stimulates bacterial adherence to monocyte CR3 (CD11b/CD18).

Bordetella pertussis, the causative agent of whooping cough, adheres to human monocytes/macrophages by means of a bacterial surface-associated protein, filamentous hemagglutinin (FHA) and the leukocyte integrin, complement receptor 3 (CR3, alpha M beta 2, CD11b/CD18). We show that an FHA Arg-Gly-Asp site induces enhanced B. pertussis binding to monocytes, and that this enhancement is blocked by antibodies directed against CR3. Enhancement requires a monocyte signal transduction complex, composed of leukocyte response integrin (alpha? beta 3) and integrin-associated protein (CD47). This complex is known to upregulate CR3 binding activity. Thus, a bacterial pathogen enhances its own attachment to host cells by coopting a host cell signaling pathway.

Adhesins, Bacterial↗
PubMed1994

Production of human PTH(1-34) via a recombinant DNA technique.

The production of hPTH(1-34) by site specific chemical cleavage of [Cys35]hPTH(1-84) obtained by a biotechnology technique is described. The amino-peptide bond of S-cyanylated cysteine residues in peptides or proteins is specifically cleaved by exposure to an alkaline solution (Stark, G. R. (1977) Methods Enzymol, 47, 129-132). However, when applying this method to [Cys35]hPTH(1-84), we observed many by-products. Formation of these by-products was suppressed using a short reaction in 0.03N NaOH containing 6M urea at low temperature, and hPTH(1-34) was specifically produced. The product was indistinguishable from standard hPTH(1-34) with respect to chemical and biological characterization.

Amino Acid Sequence↗