Search PubMed⌕ Search

Biomedical subjects

M Sakai

Publications and source records attributed to M Sakai.

At least 217 records · Page 12Linked to original sources
PubMed1998

[Flow cytometric DNA analysis and MR imaging of salivary gland tumors].

We correlated the histopathology of 32 cases of salivary gland tumors with MR imaging and flow cytometric DNA analysis. All malignant tumors were invasive and/or had an ill-defined margin. Fifty-seven percent of the pleomorphic adenomas were shown as a high signal intensity area on T2 weighted images. Fifty-six percent of Warthin tumors were shown as a low or iso signal intensity area on T2 weighted images associated with the cystic portion. Sixty-seven percent of malignant tumors were characterized by DNA aneuploidy and/or a total percentage of the S-phase fraction plus the G2 + M fraction higher than 10%. It was less than 10% and the Ki-67 positive fraction was higher than 20% in all pleomorphic adenomas. The Ki-67 positive fraction was less than 20% in 78% of Warthin tumors. The histopathology of all malignant tumors, 86% of the pleomorphic adenomas, and 89% of Warthin tumors was correctly predicted by the combination of MR images and flow cytometry. We suggest that the MR images combined with flow cytometric analysis of fine needle aspiration-derived materials is useful in the pre-operative histopathologic diagnosis of salivary gland tumors.

Adenolymphoma↗
PubMed1998

Cytotoxic effect of oxidized low density lipoprotein on macrophages.

Macrophage or macrophage-derived foam cell death is one of the characteristic events in the development of cell-poor lipid-rich cores of the advanced atherosclerotic plaques. Although the in vivo mechanism for the death of macrophages is unclear, one possible candidate for the agent which induces macrophage cell death is oxidized low density lipoprotein (Ox-LDL). To investigate the mechanism of Ox-LDL-induced macrophage cell death, we have recently employed macrophage cell genetics and isolated mutant cells resistant to the cytotoxic effect of Ox-LDL from mutagenized populations of murine macrophage-derived J774 cells (Hakamata, H., Miyazaki, A., Sakai, M., Matsuda, H., Suzuki, H., Kodama, T., and Horiuchi, S. (1998) J. Lipid Res. 39, 482-494). The results obtained showed that one mutant form, JO21b cells, was characterized by reduced expression of type I and type II class A macrophage scavenger receptors (MSR-AI/AII) with a concomitant decrease in the uptake of Ox-LDL. Moreover, peritoneal macrophages obtained from MSR-AI/AII-knockout mice showed a higher resistance to the cytotoxic effect of Ox-LDL compared to those of their wild-type littermates. From these results, we have concluded that Ox-LDL cytotoxicity to macrophages is enhanced by effective endocytic uptake of Ox-LDL through MSR-AI/AII. These findings imply a possibility that formation of the cell-poor lipid-rich core is also enhanced by MSR-AI/AII-mediated uptake of Ox-LDL and subsequent macrophage cell death in atherosclerotic lesions.

Animals↗
PubMed1998

Isolation of macrophage-like cell mutants resistant to the cytotoxic effect of oxidized low density lipoprotein.

A high concentration of oxidized low density lipoprotein (Ox-LDL) showed a cytotoxic effect on mouse macrophage-derived J774 cells. Mutant cells were selected from these cells that were resistant to the cytotoxic effect of Ox-LDL. One mutant form, named JO21b cells, was characterized in the present study. In spite of a marked resistance to the cytotoxic effect of Ox-LDL, JO21b cells were apparently as sensitive as the parent cells not only to toxic moieties of Ox-LDL, such as 7-ketocholesterol and lysophosphatidylcholine, but also to t-butyl hydroperoxide, an artificial lipid hydroperoxide analog. However, the cellular association of 125I-labeled Ox-LDL with, and subsequent endocytic degradation by JO21b cells was reduced by 70-80% compared with J774 cells. Similarly, accumulation of cholesteryl esters in JO21b cell by Ox-LDL was also reduced by 70%. Northern blot analyses of type I and type II macrophage scavenger receptors (type I and type II MSR) demonstrated that the mRNA levels of JO21b cells were lower than those of J774 cells. Moreover, peritoneal macrophages obtained from MSR-knockout mice showed a higher resistance to the cytotoxic effect of Ox-LDL than those from their wild-type littermates. Our results suggest, therefore, that macrophage scavenger receptor-mediated endocytic uptake of oxidized low density lipoproteins (Ox-LDL) may play an enhancing role in Ox-LDL cytotoxicity to macrophages or macrophage-derived cells.

Animals↗
PubMed1998

[Patho-MR imaging study in the putaminal margin in multiple system atrophy].

The slit hyperintensity of the lateral margin of the putamen in T2 weighted MRI is a characteristic finding in those patients with multiple system atrophy (MSA) involving extrapyramidal system. In spite of some speculations such as demyelination, gliosis, iron deposition or increased extracellular fluid, the nature of the abnormal signal intensity has still been remained uncertain. In this paper, we report the coincidental findings of pathology and magnetic resonance imaging of the putaminal margin in a case of MSA. The patient was sixty three years old woman with nine years history of intreatable parkinsonism, mild ataxia and dysautonomia. At six months prior to her death, 0.5T MRI showed the pontocerebellar system atrophy, slit hyperintensity in the bilateral outer margin and left inner margin of the putamen in T2 weighted image as well as linear hypointensity in T1 weighted image. The neuropathological examinations showed severe degeneration in the olivopontocerebellar and striatonigral systems, and glial cytoplasmic inclusion in widespread regions in the brain. The putamen showed severe degeneration with rarefaction. The intertissue space was observed at the outer putaminal margin in both sides and inner margin in left side, which seemed to be caused by severe shrinkage and rarefaction of the putamen. Thus, slit hyperintensity in the putaminal margin in MSA was disclosed to represent widened intertissue space.

Female↗
PubMed1998

Aberrant regulation of bone trace elements in motheaten and osteopetrosis mutant mice.

Increasing numbers of genetic diseases involving bone development and models for these diseases have been identified recently. Analysis of these bone diseases have revealed that regulated action of multiple growth factors and subsequent signal transduction are essential for normal bone formation. In this paper, two murine mutant mice viable motheaten and osteopetrosis are analyzed. Mice with the recessive 'viable motheaten' mutation express a severe immunodeficiency syndrome and bone defects. Mutations at the motheaten locus were shown to be the result of aberrant splicing of the gene encoding hematopoietic cell phosphatase (Hcph). Mice homozygous for the osteopetrosis mutation develop congenital osteopetrosis due to a severe deficiency of osteoclasts. It has been recognized that bone trace element composition analysis helps to define bone-related physiological conditions. We have analyzed bone trace element composition in viable motheaten and osteopetrosis mutant animal models in this study. In order to gain insights into the effects of particular genetic defects on bone trace element composition, inductively coupled plasma atomic emissions spectrometry (ICP-AES) analysis was performed. Marked changes in bone trace element levels were found in limb bones of viable motheaten and osteopetrosis mutant mice. An assessment of these trace element spectrum in the two mutant models with respect to each genetic defects are discussed in this paper.

Animals↗
PubMed1998

[A case report of aortic regurgitation associated with rheumatic arthritis].

We report a rare case of aortic regurgitation (AR) associated with rheumatic arthritis (RA). A 61-year-old female was admitted to our hospital with severe heart failure due to AR. She had a 8-year history of RA and had been treated with steroid therapy. Trans-esophageal echocardiography showed thickness and shortening of non coronary cusp (NCC) of aortic valve. After treated for heart failure, aortic valve replacement with SJM-HP 17 mm was done. At operation, right and left coronary cusps were almost normal, but NCC was thickened and shortened. The valve of NCC histology showed granuloma. She recovered uneventfully. Two cases of cardiac valvular disease, associated with granuloma of RA, were reported in Japan. We discussed these cases in this paper.

Aortic Valve↗
PubMed1998

[Application of heparin-coated PCPS for traumatic cardiac rupture: report of a case].

Application of heparin-coated percutaneous cardio-pulmonary support system (PCPS) for a case with traumatic cardiac rupture is reported. A 50-year-old woman, who was injured in the traffic accident, was admitted to our hospital. Her consciousness was not alert in circulatory collapse. Echocardiography showed cardiac tamponade and pericardial centesis was done followed by re-filling. Urgent surgical intervention was necessary. When she was brought to operating room, she became cardiac arrest, necessitating cardio-pulmonary resuscitation followed by PCPS. Under PCPS support, hemodynamic state became stable and cardiac laceration was repaired. Laparotomy was also done because of the distension of abdomen during operation, and splenectomy was necessary for the injured spleen. She is doing well now. Generally, it is considered to be contra-indicated to apply PCPS for traumatic cases which may cause bleeding tendency because of anti-coagulant therapy. But this case report showed the possibility of application of PCPS for traumatic cases, if PCPS is established using heparin-coated system.

Accidents, Traffic↗
PubMed1998

[Usefulness of percutaneous cardiopulmonary bypass support in patients with difficulties in weaning from cardiopulmonary bypass].

A percutaneous cardiopulmonary support system (PCPS) was used in 12 patients (mean age 68 years) between March 1991 and June 1996 for difficulties weaning from ordinary cardiopulmonary bypass. Cardiac procedures preceding the placement of the PCPS were coronary artery bypass grafting in 8 patients, aortic valve replacement in 1, double valve replacement in 1, and ascending aortic replacement for acute aortic dissection in 1. These procedures were elective in 6 patients and emergent in 6. Intraaortic balloon pumps were used in all cases except in two cases with atherosclerotic occlusive disease. Nine (75%) of the patients were weaned from PCPS, and seven (58%) were discharged. There were no complications due to the placement of PCPS except for three episodes of lower leg ischemia. We conclude that PCPS is useful in addressing difficulties in weaning from ordinary cardiopulmonary bypass and there should be further discussion about the limitations of PCPS in cases of severe circulatory failure.

Aged↗
PubMed1998

[Radiotherapy for carcinoma of the buccal mucosa: analysis of prognostic factors].

The radiotherapeutic results of 55 patients with carcinoma of the buccal mucosa were analyzed to determine the prognostic factors and appropriate treatment modality. They were classified into 5 groups according to treatment modality: group A (preoperative radiotherapy followed by surgery), group B (interstitial implant), group C (electron therapy), group D (mainly external radiotherapy) and group E (external radiotherapy followed by mold therapy with remote afterloading system). The overall 5-year survival rates for groups A, B, C, D, E and the entire group were 50%, 61%, 67%, 29%, 25% and 48%, respectively. The cumulative 5-year local control rates for groups A through E were 81%, 94%, 75%, 33% and 25%, respectively. In univariate analysis, T stage (T1-2 vs. T3-4), N stage (N0 vs. N1-3), clinical stage (II vs. III-IV), histologic grade (well differentiated vs. moderately and poorly differentiated) and treatment modality (A-C vs. D-E) were significantly related to overall survival (p < 0.05). Multivariate analysis revealed that treatment modality (groups A-C) and N0 stage were significantly associated with favorable prognosis (p < 0.05). These results suggest that interstitial implants are comparable with surgery for T1 to early T3 lesions, with or without slight invasion to the bucco-alveolar sulci or retromolar areas, that can be treated with a single-plane implant.

Adult↗
PubMed1998

[An autopsied case of multiple system atrophy with remarkable cerebral atrophy].

In this paper, we report the pathological findings of a multiple system atrophy (MSA) patient with remarkable frontal lobe atrophy. The patient was a 65-year-old woman with a 13-year history of untreatable parkinsonism, dysautonomia and progressive motor aphasia. The cranial imaging study disclosed progressive atrophy of the frontal lobe, striatum and pontocerebellar system. She died of pneumonia. The brain weight was 810 g, and there was remarkable atrophy of the cerebrum predominantly in the frontal lobe, striatum, pons and cerebellum. The microscopic examination revealed a preserved cortical structure with laminar gliosis in the sixth layer of the precentral and superior frontal gyri of the frontal lobe, and postcentral gyrus and inferior parietal lobule of the parietal lobe. The cortices of these regions also revealed to be in a spongy state in the second layer, and mild cell loss was seen in the fifth and six layers. The frontal lobe white matter showed a slight pallor, a mild loss of myelinated fiber and axon, and mild gliosis. Glial cytoplasmic inclusions (GCIs) were abundantly observed in the deep layer of the cortex in the regions mentioned above, and were more abundant in the white matter of the frontal and parietal lobes, callosal body, and internal, external and extreme capsules. There were severe degenerations in the olivopontocerebellar and striatonigral systems, and GCIs in widespread regions of the brain. We could not detect any Pick bodies, Lewy bodies, ballooned neurons, senile plaques, or any significant amounts of neurofibrillary tangles. There were no vascular changes. Thus, this was a verified MSA patient with progressive aphasia and remarkable frontal lobe atrophy. We indicate a possible involvement of the cerebral lobes in MSA.

Aged↗
PubMed1998

Studies on the migratory properties of epithelial cells of cholesteatoma: clinical investigation.

A total of 302 cholesteatoma cases were surgically treated with or without utilizing the cholesteatoma matrix to cover the defect of the eardrum. The recurrence rate, the number of days required for the skin to dry (epithelialization), findings of the external ear canal, the degree of postoperative crust formation (migration property), and the number of infections were compared between these two groups. Recurrence of cholesteatoma was seen in only one case, a case in which the cholesteatoma matrix was not used. The average number of days required for the skin to dry after surgery was 7.1 days in patients in whom the cholesteatoma epithelium was utilized, while it was 9.4 days in patients in whom cholesteatoma matrix was not utilized. The number of cases that had crust formation was significantly greater among patients in whom the cholesteatoma matrix was not utilized. From these results, we concluded that one-stage tympanoplasty with mastoid obliteration using the cholesteatoma matrix is a rational surgical procedure.

Adult↗
PubMed1998

A clinical study of the nasal dilator Nozovent in Japanese subjects.

A nasal dilator (Nozovent) has been developed to fit in the nasal cavity and external nose of Caucasians, and beneficial effects have been confirmed. However, the ability of the device to dilate nasal valve areas of Orientals, whose external nose structure differs from that of Caucasians, has not been studied. We studied the effectiveness of the Nozovent device in preventing snoring and sleep apnea in Japanese subjects according to the methods described by Petruson. When the Nozovent device was worn by the eighteen subjects who experienced snoring, nine showed significant improvement, four showed good improvement, two fair improvement, and three discontinued the trial; the rate of improvement was 72.2%. The device was also seen to be effective for three patients with sleep apnea. The Nozovent device provides a unique method for non-surgical treatment of snoring, and the effectiveness is a result of dilatation of the nasal valve area. The principle is medically sound, and is equally applicable to nasal valves of both Caucasians and Japanese who have different external nose structures.

Adult↗