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Biomedical subjects

Y Miyamoto

Publications and source records attributed to Y Miyamoto.

At least 181 records · Page 10Linked to original sources
PubMed1999

Immunohistochemical analysis of Bcl-2, Bax, Bcl-X, and Mcl-1 expression in pancreatic cancers.

Expression of several members of the Bcl-2 family proteins was investigated by means of both immunohistochemical analysis in 30 invasive ductal adenocarcinomas and 23 intraductal papillary-mucinous tumors (IPMTs) and immunoblot analysis in 6 cancer tissues and 7 pancreatic cancer cell lines. We found that Bcl-2 was expressed in 23%, Bax in 53%, Bcl-X in 90%, and Mcl-1 in 90% of the invasive ductal adenocarcinomas. In intraductal papillary-mucinous adenocarcinomas, the expression rate of Bax was 44% and those of Bcl-XL and Mcl-1 were 88%; these values were higher than those for intraductal papillary-mucinous adenomas. Immunoblot analysis identified Bcl-XL as the predominant form of the Bcl-X protein in both pancreatic cancer tissues and cell lines, and demonstrated that both Bcl-XL and Mcl-1 protein levels were uniformly high in all cell lines. These results suggest that an imbalance between antiapoptosis proteins (such as Bcl-2, Bcl-XL, and Mcl-1) and proapoptotic proteins (such as Bax and Bcl-Xs) is involved in the distinctive biologic features of adenocarcinomas of the pancreas. Furthermore, predominantly high expressions of Bcl-XL and Mcl-1 in intraductal papillary-mucinous adenocarcinomas might be involved in the carcinogenesis in IPMT of the pancreas.

Adenocarcinoma↗
PubMed1999

Calcification in untreated non-Hodgkin's lymphoma of the jejunum.

A 69-year-old Japanese female was admitted to our hospital due to a 2-month history of vomiting after eating. Examination of the small intestinal tract revealed a tumor with calcification in the inner portion, from the horizontal portion to the ascending portion of the duodenum, and jejunojejunostomy was performed. The pathological findings of the tumor gave a diagnosis of non-Hodgkin's lymphoma, diffuse small cleaved cell (Working Formulation classification), B cell type, of the jejunum. Calcification is rarely found in untreated malignant lymphoma and 15 cases of untreated malignant lymphoma with calcification have been reviewed.

Adolescent↗
PubMed1999

Nucleocytoplasmic protein transport and recycling of Ran.

The active transport of proteins into and out of the nucleus is mediated by specific signals, the nuclear localization signal (NLS) and nuclear export signal (NES), respectively. The best characterized NLS is that of the SV40 large T antigen, which contains a cluster of basic amino acids. The NESs were first identified in the protein kinase inhibitor (PKI) and HIV Rev protein, which are rich in leucine residues. The SV40 T-NLS containing transport substrates are carried into the nucleus by an importin alpha/beta heterodimer. Importin alpha recognizes the NLS and acts as an adapter between the NLS and importin beta, whereas importin beta interacts with importin alpha bound to the NLS, and acts as a carrier of the NLS/importin alpha/beta trimer. It is generally thought that importin alpha and beta are part of a large protein family. The leucine rich NES-containing proteins are exported from the nucleus by one of the importin beta family molecules, CRM1/exportin 1. A Ras-like small GTPase Ran plays a crucial role in both import/export pathways and determines the directionality of nuclear transport. It has recently been demonstrated in living cells that Ran actually shuttles between the nucleus and the cytoplasm and that the recycling of Ran is essential for the nuclear transport. Furthermore, it has been shown that nuclear transport factor 2 (NTF2) mediates the nuclear import of RanGDP. This review largely focuses on the issue concerning the functional divergence of importin alpha family molecules and the role of Ran in nucleocytoplasmic protein transport.

Animals↗
PubMed1999

Colour Doppler ultrasound for the evaluation of bowel wall thickening.

We performed colour Doppler ultrasound to evaluate bowel wall thickening and to determine the effectiveness of this modality. 42 patients (aged 8-83 years old, mean age 43.5 years) with bowel disease underwent both grey scale and colour Doppler ultrasound examinations. The diagnoses were classified into three categories: inflammation, vasculitis or ischaemia. The bowel wall thickness, wall echotexture and location of the involved portion were all recorded by grey scale ultrasound, while the presence of an intramural colour Doppler flow and arterial signal was evaluated by colour Doppler ultrasound. The colour Doppler flow was graded as "absent", "mild", or "abundant", and the resistive index was also calculated. Bowel wall thickening was observed in the bowel diseases demonstrating inflammation, vasculitis and ischaemia. Patients with ischaemia were significantly older than those with inflammation. The difference in bowel wall thickness was not significant among the disease categories. Differences in bowel wall echotexture, colour Doppler flow, arterial signal and resistive index among the disease categories were significant. The absence of a colour Doppler flow and of an arterial signal suggested ischaemia, while in younger patients, an abundant colour Doppler flow and a stratified echotexture suggested inflammation. The mean resistive index in the ischemic group was significantly higher than that in the inflammatory group. In conclusion, both grey scale and colour Doppler ultrasound are considered to provide useful information for evaluating and differentiating bowel wall thickening in various bowel diseases.

Adolescent↗
PubMed1999

Spontaneous pinealoma in a male Crj:CD (SD) IGS rat.

A pinealoma (benign) was found in a 61-week-old male Crj:CD (SD) IGS rat. The neoplasm was located between the cerebral hemispheres and the cerebellum. Histologically, the tumor cells consisted of two cell types: large, pale-staining cells and small dark-staining cells. A fibrovascular stroma divided the tumor cells into incomplete lobules or nest structures. Relatively numerous mitoses were noted in the tumor cells. Ultrastructurally, the tumor cells contained dense-cored vesicles, approximately 120 nm in diameter.

Animals↗
PubMed1999

[Diagnosis of thyroid nodules by Doppler ultrasonography: a comparison between color Doppler and power Doppler ultrasonography].

The purpose of this study was to assess the usefulness of color and power Doppler imaging in thyroid nodules. The following 4 items were compared between malignant thyroid nodules (34 cases) and benign nodules (51 cases): 1) vascularity; 2) distribution of tumor vessels (none, marginal, peripheral, central); 3) nature of tumor vessels (tortuosity, interruption); and 4) FFT analysis. The distribution of tumor vessels on color Doppler images, nature of tumor vessels on power Doppler images, and the indices of PI, RI, and ATI in FFT analysis were useful in making the differential diagnosis between malignant and benign nodules. In terms of vascularity, including the distribution of tumor vessels on power Doppler images and nature of tumor vessels on color Doppler images, no statistically significant differences were found between malignant and benign nodules. Power Doppler images depicted tumor vessels in more detail than color Doppler images and were considered to extend the application of FFT analysis.

Diagnosis, Differential↗
PubMed1999

[Management under anesthesia of a patient with renal cell carcinoma extending into the retrohepatic inferior vena cava with the aid of partial cardiopulmonary bypass].

A 70-year-old male with renal cell carcinoma extending into the retrohepatic inferior vena cava was scheduled for radical nephrectomy with vena caval resection under general anesthesia. He had received partial gastrectomy for gastric cancer twelve years before. Computed tomography and inferior vena cavography confirmed that the vena cava was almost completely occluded and that a collateral venous network was well established. It was considered that the surgical approach to the retrohepatic cavals area was technically very difficult, and that there was a high possibility of a pulmonary embolus during the surgical manipulation. To prevent a pulmonary embolus and get good control of the vena cava above the tumor and below the hepatic vein, we decided to use a partial cardiopulmonary bypass (CPB) until the vena cava was clamping above the tumor. Anesthesia was induced with propofol and fentanyl, and maintained with fentanyl and isoflurane-N2O-O2. In the partial CPB blood from the hepatic vein was drained from the inferior vena cava cannula through right atrium, oxygenated by microporus membrane oxygenator, and returned to the left femoral artery. Cannulation to drain the venous circulation entering the vena cava below the tumor was abandoned because the extensive collateral venous network ultimately drains into the superior vena cava. The partial CPB time was 90 min, and the bladder temperature during the CPB was 35-36 degrees C. During the 7.3 hr procedure, the pulmonary embolus did not occur and the total blood loss was 5515 ml. The patient made an uncomplicated recovery and was discharged 30 days after the operation. This newly reported partial-CPB method may be safe and effective for the management under anesthesia of other patients.

Aged↗
PubMed1999

[Intracerebral hemorrhage associated with long-lasting deficiency of factor XIII].

A 5-year-old boy had an intracerebral hematoma evacuated from the left parieto-occipital region at a local hospital. There was a difficulty in hemostasis during the operation. Postoperatively his neurological state gradually deteriorated. CT scans showed a gradual increase in intracerebral hemorrhage at the operated site. He was transferred to our clinic for further treatment. The preoperative blood coagulation profile showed that the activity of factor XIII was only 4%. The hematoma was removed without any trouble under administration of factor XIII. Postoperative course was also uneventful although the plasma level of factor XIII did not go up higher than 26% in spite of its daily administration. Although factor XIII administration was terminated one month after cranioplasty, the patient showed good recovery and the level of factor XIII spontaneously normalized in 6 months. The cause of the extremely low level of factor XIII in this case is not known, but it could be ascribed to massive hemorrhage.

Cerebral Hemorrhage↗
PubMed1999

[Surgical treatment for distal aortic arch aneurysm using stent grafting].

To alleviate the invasiveness of surgical treatment for distal aortic aneurysm or dissection, we have been using a stented graft to replace the distal anastomotic suture of the descending aorta. We also developed a new stent graft implanting method for distal aortic aneurysm or dissection which uses cervical branch bypasses from the ascending aorta and requires no extracorporeal circulation. These new surgical treatments for distal arch aneurysm result in low surgical mortality (3.8%) and low surgical morbidity rates (stroke, 7.7%; respiratory complications, 7.7%; no renal complications). These results indicate that these new graft implanting methods using stent graft should be considered as a less-invasive surgical treatment for distal aortic aneurysm or dissection.

Aged↗
PubMed1999

Characterization of positive inotropic effect of colforsin daropate [correction of dapropate] hydrochloride, a water-soluble forskolin derivative, in isolated adult rat cardiomyocytes.

The present study was undertaken to characterize the positive inotropic action of colforsin daropate [corrected] hydrochloride (NKH477), a novel water-soluble forskolin derivative, on isolated cardiomyocytes of adult rats. Simultaneous measurements of cellular contraction and intracellular calcium concentration ([Ca2+]i) were carried out. The effects of isoprenaline and ouabain on these parameters were also determined for comparison. The contraction and maximum [Ca2+]i of NKH477-, isoprenaline-, or ouabain-treated cells were increased concentration dependently. Peak shortening of NKH477-treated cells was positively correlated with the shortening velocity and inversely with the time to peak shortening. Maximum, but not minimum, [Ca2+]i in NKH477-treated cells was correlated with the rate of increase in [Ca2+]i and inversely with the time to maximum [Ca2+]i. Similar results were obtained with isoprenaline. In contrast, ouabain increased both maximum and minimum [Ca2+]i. Treatment with either NKH477 or isoprenaline increased cellular cAMP content, but treatment with ouabain did not. These results suggest that the positive inotropic action of NKH477 is associated with an increase in [Ca2+]i and acceleration of its kinetics.

Animals↗
PubMed1999

[Power Doppler US in breast masses: correlation of spectral analysis findings with pathological features].

The purpose of this study was to clarify the usefulness of power Doppler imaging for the diagnosis of breast masses. Materials were histologically confirmed breast masses: 24 benign lesions, 4 non-invasive carcinomas, and 54 invasive carcinomas. In invasive breast carcinoma, pathological examination was used to classify the degree of intratumor fibrous stroma (IFS) into three groups. The relationships between IFS and Doppler spectral parameters (Vmax, Vmin, PI, RI) were evaluated retrospectively. High PI and low Vmin values were well correlated with IFS grade. Carcinomas with low IFS grades had higher Vmax values than benign lesions.

Adult↗
PubMed1999

Frequency distribution of axon diameters in the left aortic nerve of the rat raised in space--Neurolab Program.

INTRODUCTION: To study development of the aortic baroreflex mechanisms under conditions of microgravity, we carried out the various experiments in the neonate rats aged 25 days raised in microgravity for 16 days (flight: FLT group) in Neurolab program (STS-90, space shuttle Columbia, launch date: Apr 17, '98. Some results of the experiments were already reported. The results of histological examination of the aortic nerve which is the afferent of the aortic baroreflex showed that the number of unmyelinated fibers in FLT was significantly less in than those in two control groups and there was no difference between FLT and each control group in the analysis of myelin. In the present paper, the frequency distribution of axon diameters of the left aortic nerves in FLT was compared to that in two ground control groups to examine the growth of the aortic nerve fibers in space. METHODS: After breeding Sprague-Dawley rats for 16 days in the shuttle in space and in the animal center in the Kennedy space center, a total of 43 deeply anesthetized rats were perfused with 1% parahormaldehyde and 1% glutaraldehyde or 4% parahormaldehyde solution buffered at pH7.4 with 0.12 M phosphate solution. Concerning the control groups, one group was the asynchronous ground control (AGC) group in which the rats were housed in the same cages as those on the shuttle, and the other was the vivarium ground control (VIV) group in which the rats were housed in commercial cages. The cervical region of the left aortic nerve which is a branch of the vagus was cut off and stored in the same fixative as that used for perfusion, and postfixed in the solution of 1% OsO4, for 2 hours within 24 hours after the perfusion. The fixed specimens were embedded in epoxy resin blocks by the usual method for electron microscopy following dehydration. Electron microscopic montages of transverse sections of these nerve trunks were made from the five left aortic nerves in each group. The magnification of the montages was approximately 13400 times. The long and short axes (a and b) of the nerve fibers and the myelin thickness (T) were measured with a caliper and the axon diameters (R were calculated by following formula: R2=[(a-2T)2+(b-2T)2]/2.

Animals↗