Search PubMed⌕ Search

Biomedical subjects

T Miyake

Publications and source records attributed to T Miyake.

At least 163 records · Page 9Linked to original sources
PubMed1994

Anti-ubiquitin immunoreactivity associates with pyramidal cell death induced by intraventricular infusion of leupeptin in rat hippocampus.

Pathological studies on several neurodegenerative diseases including Alzheimer's disease have revealed common deposition of ubiquitin in many inclusion bodies. This implies a possible association of ubiquitin with neurodegeneration. To address this possibility, we examined histochemically the effect of intraventricular infusion of leupeptin, a thiol proteinase inhibitor, which is known to elevate anti-ubiquitin immunoreactivity in rat Purkinje cells. In the leupeptin-infused rat, an intense anti-ubiquitin immunoreactivity in the cytoplasm of neurons occurred not only in cerebellar Purkinje cells but also elsewhere in a wide area of the rat brain. The increase in the immunoreactivity was followed by a gradual depletion of pyramidal neurons in the hippocampal CA1 and CA3 subfields. The immunoreactive neurons disappeared concurrently. The number of anti-ubiquitin immunoreactive neurons was negatively correlated with that of surviving neurons when the duration of leupeptin infusion was varied. These results suggest that increased anti-ubiquitin immunoreactivity associates with neuronal death in leupeptin-treated rat brain.

Animals↗
PubMed1994

Malunited Colles' fracture. Analysis of stress distribution.

To try to explain disability in the wrist after malunited Colles' fractures, an experiment was designed to evaluate pressure distribution through the wrist joint with varying degrees of angulation of the distal radius. The results of computer simulation analysis of stress concentration using finite element methods were compared with those of pressure distribution studies on the radial articular surface of cadaveric radii in various positions using pressure-sensitive film. Stress existed in volar regions of the radio-lunate joint under normal pressure in the neutral position, but shifted to dorsal regions of the joint, and was concentrated when dorsal angulation reached 30 degrees. We believe that concentrated loads result in pain and may lead to early degenerative joint disease. Early additional reduction of a displaced fragment or a post-fusion osteotomy should be considered when dorsal angulation exceeds 30 degrees in malunited distal radial fractures to decrease abnormal loading across the wrist joint.

Adolescent↗
PubMed1994

A morphologic analysis of 'naked' islets of Langerhans in lobular atrophy of the pancreas.

The 'naked' islets of Langerhans (NIL) in randomly selected autopsy cases and in cases of chronic alcoholic pancreatitis, cystic fibrosis, and pancreatic carcinoma were studied histopathologically. The NIL were found in 55 of 164 randomly selected cases, with age-related frequency, in 21 of 30 cases of chronic alcoholic pancreatitis, in 2 of 2 cases of cystic fibrosis, and in 25 of 32 cases of pancreatic carcinoma. The NIL were frequently accompanied by ductal alterations: epithelial metaplasia and hyperplasia in randomly selected cases, protein plugs in chronic alcoholic pancreatitis, mucus plugs in cystic fibrosis, and obliterated ducts in pancreatic carcinoma. The NIL in randomly selected cases may have been formed by ductal alterations that caused stenosis of the lumen, those in chronic alcoholic pancreatitis and cystic fibrosis were the result of protein or mucus plugging, and those in pancreatic carcinoma were a result of neoplastic involvement of the distal pancreatic duct. Therefore, the common factor in the development of NIL is thought to be obstruction of the pancreatic duct system, and in cases of NIL that have a multilobular distribution and interinsular fibrosis, a diagnosis of chronic pancreatitis can usually be made.

Adolescent↗
PubMed1994

[Viral etiology in travellers' diarrhea].

Virological examinations were performed on stools obtained from 1,264 overseas travellers with diarrhea at Nagoya International Airport between 1986 and 1991. Group A rotavirus was detected in 11 samples (0.87%) by latex agglutination method, but other viral agents such as atypical rotaviruses and small round structured viruses were not observed by electron microscopic analysis. Rotaviruses were detected in various age groups, but the positive rate of rotavirus in females (6/398) was higher than that in males (5/866). Seasonal variation in the detection of rotavirus was observed. Entero 71 was isolated from one of 11 rotavirus-positive cases, but the other 10 cases were not associated with enteroviruses. All rotavirus-positive cases were negative for isolation of enteropathogenic bacteria.

Adolescent↗
PubMed1994

Effect of cepharanthin and cytochalasin D on platelet internalization of anti-glycoprotein IIb/IIIa antibodies.

The effects of cepharanthin and cytochalasin D on the internalization of anti-glycoprotein IIb/IIIa antibodies by platelets were investigated in 13 patients with chronic immune thrombocytopenic purpura who had circulating anti-glycoprotein IIb/IIIa autoantibodies. Unfixed platelets were incubated with a monoclonal anti-glycoprotein IIb/IIIa antibody (NNKY1-32) or with platelet-binding IgG from the patients (which contained anti-glycoprotein IIb/IIIa antibodies). Flow cytometry showed that the binding of NNKY1-32 to platelets was markedly decreased after incubation for 120 min compared with incubation for 10 min. This decrease was inhibited by cepharanthin but not by cytochalasin D. Platelet-binding IgG also showed markedly reduced binding after incubation for 120 min compared with 10 min, and this decrease was inhibited by both cepharanthin and cytochalasin D. Cytochalasin D inhibits platelet cytoskeletal activity while cepharanthin does not. Therefore, our results suggest that the internalization of anti-glycoprotein IIb/IIIa antibodies from the plasma of patients with immune thrombocytopenic purpura is related to platelet cytoskeletal reorganization, while the cytoskeleton did not participate in internalization of the monoclonal anti-glycoprotein IIb/IIIa antibody (NNKY1-32). Cepharanthin may be useful for studying the internalization and cycling of glycoprotein IIb/IIIa in human platelets, and it may also be potentially useful for the treatment of immune thrombocytopenic purpura.

Alkaloids↗
PubMed1994

Amyloid beta-protein precursor-rich platelet microparticles in thrombotic disease.

We investigated the association of amyloid beta-protein precursor (APP) and platelet derived microparticles in 20 normal controls and 91 patients with various diseases causing a thrombotic tendency. Compared with the controls, the mean percentage of APP-positive microparticles was significantly greater in the patients with cerebral infarction (39.1 +/- 17.7%, p < 0.001), diabetes (31.1 +/- 12.6%, p < 0.001), and uremia (30.1 +/- 14.7%, p < 0.01), but not in those with hypertension (8.2 +/- 6.3%, p = NS). Sixteen patients with cerebral infarction, 20 with diabetes, and 11 with uremia had microparticles with very high APP levels. In normal controls, 7.2 +/- 3.7% of the microparticles were positive for P-selectin, while the percentage in cerebral infarction, diabetes, uremia, and hypertension was respectively 43.5 +/- 15.1%, 40.0 +/- 12.8%, 31.8 +/- 12.2%, and 11.6 +/- 7.3%. There was a significant correlation between P-selectin and APP positivity of microparticles. Our results suggest that microparticle APP may have a regulatory influence on coagulation abnormalities.

Amyloid beta-Protein Precursor↗
PubMed1994

[Corneal autofluorescence in eyes with branch retinal vein occlusion].

Basic studies have suggested that corneal autofluorescence, originating from flavoprotein and pyridine nucleotides, is caused by metabolically impaired corneal mitochondrial respiration. In this study, we used corneal autofluorescence as a parameter for evaluating the pathology at the corneal cell level in eyes with branch retinal vein occlusion. Unilateral branch retinal vein occlusion cases with durations of 2 months to 7 years since the onset and age-matched normal eyes were used for the study. The corneal autofluorescence was measured with a Fluorotron Master, with a special device attached to measure the anterior segment at the corneal peak. The autofluorescence was 15.6 +/- 5.8 (n = 68), 13.8 +/- 4.0 (n = 68), 14.2 +/- 3.7 (n = 14), and 14.0 +/- 3.6 (n = 14) (ng Eq/ml, mean +/- SD), respectively, in eyes with branch retinal vein occlusion, their fellow eyes, normal controls, and their fellow eyes. The affected eyes showed statistically significantly higher autofluorescence than the fellow eyes; there was no essential difference among the fellow eyes of those with branch retinal occlusion, normal controls, and their fellow eyes. The eyes with branch retinal vein occlusion, which is a focal retinal lesion, commonly exhibit corneal cellular pathologies.

Aged↗
PubMed1994

[A case of hypertrophic obstructive cardiomyopathy (HOCM) complicated by infective endocarditis (IE) and mitral regurgitation (MR)].

The case of a 56-year-old man who underwent mitral valve replacement due to HOCM complicated by IE and MR is reported. Preoperative 2D echocardiographic assessment of the mitral valve revealed systole anterior motion (SAM) and vegetation, and color flow Doppler echocardiographic examination revealed severe mitral regurgitation. The left ventricular out-flow tract gradient decreased from 140 mmHg preoperatively to 60 mmHg postoperatively. Mitral valve replacement should be considered in patients with associated IE and severe MR.

Cardiomyopathy, Hypertrophic↗
PubMed1993

Allocation of mouse cerebellar granule cells derived from embryonic ventricular progenitors--a study using a recombinant retrovirus.

Granule cells of the mammalian cerebellar cortex originate from embryonic progenitors present in the ventricular germinal layer. To investigate the allocation fate of these ventricular progenitors in the mouse, we labeled a few of them on embryonic day 13 with a recombinant retrovirus carrying lacZ which encodes E. coli beta-galactosidase (beta-gal), and the labeled cells in the postnatal cerebellar cortex were detected by beta-gal histochemistry. In the postnatal cerebellar cortex, the virally-labeled beta-gal+ granule cells formed discrete clusters. These clusters were not compactly packed with the beta-gal+ cells, and there was intermingling with beta-gal- granule cells. Neither beta-gal+ Purkinje cells nor glia were found to be included in the clusters. Most of the granule cell clusters were incompatible with the functional areas of the cortex. These results suggest: (1) granule cells derived from individual ventricular progenitors are allocated in clusters and are not extensively dispersed, (2) granule cells descended from one progenitor may mix with their neighbors that are descended from another progenitor, (3) the allocation fate of the ventricular progenitors of granule cells is not restricted to the functional areas of the cerebellar cortex.

Animals↗
PubMed1993

Interaction of activin A and gonadal steroids on FSH secretion from primary cultured rat anterior pituitary cells.

To clarify the mechanism of FSH secretion from the pituitary induced by activin A, we studied the interaction between activin A and gonadal steroids in inducing FSH release from primary cultured female rat pituitary cells in serum-free medium. The basal release of FSH was stimulated by activin A, testosterone (T) and progesterone (P), and T and P also facilitated basal FSH release stimulated by activin A. The GnRH-stimulated FSH release was facilitated by activin A, P and 17 beta-estradiol (E2), but suppressed by T. The effect of activin A on GnRH-stimulated FSH release was facilitated by P, but not affected by T or E2. These findings suggested that the interaction between activin A and T or P may be involved in the regulation of FSH secretion during the estrus cycle in rats.

Activins↗
PubMed1993

Developmental profile of P element transposition in Drosophila somatic cells.

Transposition of the P element during Drosophila ontogenesis was monitored. A modified P element was transposed by the P delta 2-3 transposase source. P elements inserted into the genome were cloned by the plasmid rescue at various developmental stages of the G1 hybrid to trace events in somatic cells. The transposed elements were directly counted by analyzing RFLP of genomic DNA fragments flanking the P elements. Transposition began from the late embryonic stage, but occurred rarely. Frequent transposition was observed from the late third instar to early pupal stage. From these results, transposition of the P element would appear to be affected by the developmental state of somatic host cells.

Animals↗
PubMed1993

Biplane transesophageal echo-Doppler studies of atrial septal defects: quantitative evaluation and monitoring for transcatheter closure.

Forty-four patients with atrial septal defects, aged 7 months to 18 years (median 8.9), underwent biplane transesophageal (TEE) and transthoracic (TTE) echocardiography. The size of the defect and the shunt flow volume were measured by TEE and compared with the actual size at surgery (N = 14) or the shunt volume measured by the Fick method (N = 34), respectively. In all cases the location and morphology of the defect were clearly demonstrated by TEE; on the other hand, two patients with sinus venosus-type and multiple-type defects, respectively, and one with a small ostium primum defect did not have a complete diagnosis by TTE. The defect size determined by TEE correlated well with the surgical measurement. Similarly a significant correlation was demonstrated between the shunt volume measured by TEE and that obtained by the Fick method. In three patients transcatheter closure of the atrial septal defect by means of a clamshell device was accomplished successfully with TEE monitoring. We conclude that biplane TEE provides a better appreciation of cardiac anatomy and hemodynamic evaluation than TTE in this setting, and TEE is essential for monitoring during transcatheter closure.

Adolescent↗