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Biomedical subjects

M Wakakura

Publications and source records attributed to M Wakakura.

At least 55 records · Page 3Linked to original sources
PubMed1989

Response of cultured Müller cells to heat shock--an immunocytochemical study of heat shock and intermediate filament proteins in response to temperature elevation.

Müller cells from adult rabbit retina were cultured at normal (37 degrees C) temperature and under heat shock conditions (42-43 degrees C) for either 1.5 hr or 4 hr. The presence of heat shock proteins of three different molecular weights, and of vimentin, was identified by the use of monoclonal antibodies and of GFAP by a suitable polyclonal antibody coupled in each instance with immunofluorescence microscopy or immuno-electron microscopy. Heat shock conditions resulted in the expression of HSP of molecular weights in the ranges 57-61 kD, 68 kD and 90 kD. The high level of expression of GFAP in unshocked Müller cell cultures (80-90% of cells) was reduced after 1.5 hr of heat shock to 20-30% of cells, and after 4 hr to only 5%. Although the expression of vimentin (90% of untreated cells) was only slightly reduced by heat shock (60-80% of cells) the intracellular staining pattern of vimentin was greatly altered by heat shock. Changes in the expression of HSP, GFAP and vimentin can all be regarded as part of the Müller cell response to heat shock conditions.

Animals↗
PubMed1989

[Evaluation of left atrial function by 99mTc gated blood pool scan].

99mTc gated blood pool scans were studied to assess the left atrial function. Relationship between filling time and rapid emptying time was y = 0.695 x + 109 (r = 0.761, p less than 0.05, n = 14) in LAO and LPO projections. On the other hand, relationship between slow filling and rapid emptying time was good closely (y = 0.846 x + 16.9 (p less than 0.01, r = 0.975, n = 8] in standard and retrograde acquisition. To assess the left atrial function by standard acquisition in LAO projection should be available for clinical use.

Aged↗
PubMed1989

Bilateral slowly progressive big blind spot syndrome.

A 33-year-old woman was found with bilateral enlargement of the blind spot without optic disc edema. Her bilateral peripapillary retinas appeared slightly decolored and elevated with obscure margins and fluorescein angiography indicating only slight hyperfluorescence in the late venous phase. Four years after her initial visit, both of her blind spots became enlarged further and dark adaptation was remarkably difficult. Peripapillary retinal lesions appearing as retinal pigmentary degeneration were evident with very definitive margins. The lesions showed strong hyperfluorescence in the arteriovenous phase owing to window defects. From these findings, it appears that bilateral big blind spots without optic disc edema may possibly result from peripapillary retinal degeneration, which may become evident at a much later date.

Adult↗
PubMed1989

[Application of straight chain fatty acid analog IPPA [omega-(p-iodophenyl)-pentadecanoic acid] for myocardial imaging--using acute myocardial infarction model].

Application for myocardial imaging and fundamental experiments were studied using straight chain fatty acid analog IPPA [omega-(p-iodophenyl)-pentadecanoic acid]. Biodistribution of IPPA in rabbits (n = 6) shows the accumulation in liver was maintained 81.0% at 30 minutes, while the accumulations of heart, lungs and kidneys were 30.0%, 10.0% and 15.0% respectively. Especially the accumulation of heart decreased rapidly from 48.0% at 3 minutes to 30.0% at 30 minutes, reflecting the effect of beta oxidation. On the other hand, in the acute myocardial infarction mode (n = 6), with occlusion in left anterior descending coronary artery, all 6 cases showed defect images at the corresponding areas after injection of 3 mCi of IPPA. Myocardial imaging with IPPA should be useful not only for myocardial metabolic diseases (cardiomyopathy etc.) but also for ischemic heart disease.

Animals↗
PubMed1989

[A case of metastatic lung tumor mimicking left atrial myxoma by echocardiography].

We report a case of lung metastatic tumor originated from submandibular osteosarcoma, which shows rare advancement and findings. This lung metastatic tumor advanced from left lower lung to left atrium through the left lower pulmonary vein, which penetrated to the left ventricle in the diastolic phase mimicking left atrial myxoma. 67Ga-citrate images showed that hot accumulation were recognized behind the heart in planar image and clear advancement from the lung to the heart in the SPECT image. 67Ga-citrate SPECT image should be available for cardiac tumors.

Adult↗
PubMed1989

[Cellular stress response in the eye].

The cellular stress response consists of general inhibition of normal protein synthesis and enhancement of a group of stress or heat shock proteins (SPs or HSPs). Current studies show this response system to be present in various cells from bacteria to man. A number of HSPs have been described, and four are now regarded as universal. Three are described in terms of their molecular weights of 90K, 70K and 20--30K daltons, respectively, and a fourth is known as ubiquitin. Most of these have been highly preserved throughout evolution. One important role for HSPs is certainly related to cellular homeostasis including thermotolerance. It is quite possible that cytoskeletal changes occurring during heat shock are involved in the regulation of HSP synthesis and that HSPs themselves have cytoarchitectural roles. In this review, the history of research on heat shock proteins was introduced to elucidate their functions. Cellular stress response in ocular tissues was also taken into account. For example, immunocytochemical investigations have indicated that normally less detectable glial fibrillary acidic protein in Müller cells is expressed in response to neuronal injury, degeneration, retinal detachment and under in vitro conditions. Current studies, including our own, show the accumulation of HSPs or SPs in various retinal cells (e.g. Müller cells, retinal neurons, and retinal pigment epithelia) following either herpes simplex infection or heat shock. The possible clinicopathological significance of the above cellular responses is discussed.

Animals↗
PubMed1989

[Chronic toxicity of tobacco smoke on the visual system].

The chronic toxicity of tobacco smoke on the rats visual system was studied. Six male Wistar rats had been subjected to five hour's daily passive smoking of 15 cigarettes for 52 weeks, in an attempt to produce tobacco amblyopia. Elongation of the peak latency time of N1 and P1 waves in the visual evoked potential (VEP) was recognized. Histopathologically, some degree of glial proliferation and pyknosis was observed in the optic nerves of all treated rats, and massive disappearance of nerve fibers was seen in one severely affected case. Electron microscopic examination proved that unmyelinated nerve fibers increased in number and the myelin sheath was thinner than that of the untreated control rats, while axons were relatively well preserved. The distribution in the magnitude of the axon diameter histogram was shifted towards a smaller diameter than that of the control rats. Electroretinography (ERG) did not show any significant changes of the latency and the amplitude of both a- and b- waves, and no histopathological changes were seen in the sensory retina. Neither functional nor histological changes were seen in the sciatic nerves. These results indicated that the optic nerve is thought to be more vulnerable to tobacco smoke than the peripheral nerves and we consider that a primary change of the nerve is demyelination at the retrobulbar portion of the optic nerve.

Animals↗
PubMed1988

Malignant schwannoma of the heart.

Primary cardiac tumor is an extremely rare disease entity. Only three cases of primary malignant cardiac schwannoma, the subject of this report, have been recorded in Japan. Recently, we encountered a case of malignant schwannoma in which retention of pericardial effusion was the first clinical finding. This case was a 30-year-old female, who had dyspnea at work, general fatigue, and fever. Striking cardiac expansion was seen, with a cardiothoracic ratio (CTR) of 69% on chest x-ray. Two-dimensional echocardiograms showed a large volume of pericardial effusion between the side wall of the left ventricle and the epicardium, and the presence of a parenchymatous tumor. An increase in tumor size was detected on chest computer tomography (CT) scan. Using a pump oxygenator, median sternotomy was performed to reach the epicardium. A pale yellow, soft tumor was seen in the left atrium near the left ventricle. Histologically, the patient was diagnosed as having a malignant schwannoma. We have reported a case of primary malignant schwannoma which was surmised to have arisen from the boundary between the atrium and the ventricle.

Adult↗
PubMed1988

Comparative ultrastructural study of rabbit Müller cells in vitro and in situ.

The ultrastructural appearance of cultured rabbit glial cells (putative Müller cells) has been compared with that of rabbit Müller cells in situ. Electron microscopy disclosed that the cultured cells had a basement membrane comparable to the inner limiting membrane of the retina and that villous processes adjacent to zonulae adherentes were reminiscent of fibre baskets and the outer limiting membrane. Cultured cells showed apico-basal polarisation in specimens from early passages. It was noted however that cultured cells showed a number of features which were different from normal Müller cells in situ. These included prominent rough endoplasmic reticulum, sparse smooth endoplasmic reticulum and relatively electron lucent cytoplasmic matrices. These findings resembled the appearances found in proliferating Müller cells in the human eye. The ultrastructural differences noted in the cultured Müller cells suggest that the cultured cells are in an active form.

Actin Cytoskeleton↗
PubMed1988

[Evaluation of cardiovascular responses to handgrip tests in patients with ischemic heart disease by radionuclide method].

Left ventricular responses to handgrip exercise test in patients with ischemic heart disease were assessed by RI methods. We subdivided into three groups (A: delta EF more than 5% increased, B: delta EF -5%-+5% no change, C: delta EF less than 5% reduced), left ventricular contractility (LVEF/LVET) and Tl defect score changed significantly in global EF reduced group, moreover the usefulness of handgrip test was assured. This instrument is low cost, safety, small size, and available for wide ranged ages.

Blood Pressure↗
PubMed1988

Surgical management of persistent congenital eversion of the upper eyelids.

Most cases of congenital eversion of the upper eyelids resolve spontaneously within two weeks of birth. We present a case of persistent upper-eyelid eversion that did not even after two months of conservative management. A previously undescribed mechanism, consisting of a vertical elongation of the eyelid in its posterior aspect creating a relative skin deficiency, was probably responsible for this eversion. Skin grafts provided rapid resolution with a good cosmetic result.

Down Syndrome↗
PubMed1988

Immunocytochemical characteristics of Müller cells cultured from adult rabbit retina.

The antigenic expression of glial fibrillary acidic protein (GFAP), vimentin, S-100 protein and neurofilament triplex polypeptide was examined in cultured glial (Müller) cells from adult rabbit retina using immunocytochemical techniques. Most of the cultured cells were labelled with carbonic anhydrase C which has been considered to be the most specific marker of Müller cells. Most of the cultured cells were also positive for GFAP, a result which differs from previous observations on whole retina. Using a double labelling technique, 70-90% of cultured cells showed positive labelling for GFAP and vimentin although the staining intensity was stronger in the case of the latter. Fifty to seventy percent of cultured cells showed positive immunofluorescence to S-100 protein. Immunoelectron microscopy confirmed that GFAP and vimentin were localised along the intermediate glial filaments. S-100 protein was present in both the cytoplasm and the nucleoplasm of the majority of cells, but surprisingly in approximately 30% of cells the nucleoplasm was not labelled, a result which again is different from previously reported studies on whole retina. Neurofilament triplex polypeptide was not identified either by immunofluorescence or by immunoelectron microscopy. The results indicate that Müller cells in culture show a different antigenic expression to similar cells in whole retina.

Animals↗
PubMed1987

Stress proteins accumulate in cultured retinal glial cells during herpes simplex viral infection.

The production of stress- or heat-shock proteins (SP) which are defined by three monoclonal antibodies (TI56, TG5E and TG7A) were examined in cultured retinal glial cells with and without herpes simplex virus (HSV) infection. Indirect immunofluorescence showed that 80-90% of uninfected cells reacted with anti-glial fibrillary acidic protein (GFAP) and that 10-20% of uninfected cells were weakly labelled with anti-SP antibodies. By 6 hr after HSV infection, the proportion of GFAP labelled cells decreased to 60-70% whereas cells strongly expressing SP antigens were demonstrated. At 24 hr, GFAP+ cells were markedly reduced in number and immunolabelling with anti-SP antibodies was evident in approximately 50% of cells, directly demonstrating the accumulation of SP in cultured retinal cells after HSV infection. Double labelling with GFAP/TI56 indicated that 30% of GFAP+ cells were labelled with TI56 and 30-50% of TI56+ cells were also GFAP+, despite the abrupt loss of GFAP+ cells during HSV infection. These results indicate that SP normally expressed at low level are significantly upregulated in retinal glial cells following HSV infection.

Animals↗