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Biomedical subjects

M Kusakabe

Publications and source records attributed to M Kusakabe.

121 records · Page 7Linked to original sources
PubMed1983

Immunocytochemical localization of chick DNA polymerases alpha and beta +.

An immunofluorescent method using specific antibodies was employed to detect DNA polymerases alpha and beta in chick cells. With monoclonal antibodies produced by four independent hybridoma clones, most of the DNA polymerase alpha was shown to be present in nuclei of cultured chick embryonic cells. With a polyclonal, but highly specific, antibody against DNA polymerase beta, this enzyme was also shown to be present in nuclei. DNA polymerase alpha was detected in proliferating cells before cell contact and in lesser amount in resting cells after cell contact, indicating that its content is closely correlated with cell proliferation. On the other hand, similar amounts of DNA polymerase beta were detected in proliferating and resting cells. Furthermore, DNA polymerase beta was detected in nuclei of most cells, while DNA polymerase alpha was detected only in large round nuclei in seminiferous tubules of chick testis. DNA polymerase alpha is presumably present in cells that are capable of DNA replication, and during the cell cycle it seems to remain in the nuclei during the G1, S, and G2 phases, but to leave from condensed chromatin for the cytoplasm during the mitotic phase.

Animals↗
PubMed1982

Acute functional changes of platelets in left ventricular assist in a dog model.

Left ventricular assist bypass was performed in nine dogs using pneumatically actuated blood pumps fabricated of segmented polyurethane and heparinized hydrophilic polyurethane (H-USD) newly developed so as to render excellent antithrombogenicity. The survival of the dogs ranged from 1 to 82 days. In all cases, significant reductions in platelet count and in platelet aggregability were observed. Simultaneously, severe hemorrhage from the anastomosed descending aorta occurred four to six hours after the pump implantation. This hemorrhage, leading to death, was not related to systemic heparinization, but was closely related to the mechanical impairment of platelets by the pumping operation. Five days after the pump implantation, complete recovery of the platelet aggregability was observed and no further hemorrhage occurred in the dog that survived for 82 days.

Animals↗
PubMed1981

A simple and rapid method of dissociating hepatocytes from fixed liver of the mouse.

A simple and rapid method of dissociating hepatocytes of fixed liver tissue is described. Mouse liver was fixed by vascular perfusion with sodium phosphate buffered 2% formaldehyde-2% glutaraldehyde solution containing 0.02% picric acid and then osmicated in 2% OsO4 in phosphate buffer by immersion. Hepatocytes are easily dissociated by tapping the fixed tissue blocks in distilled water with a glass rod or by ultrasonics. This method results in very low cell fragility and a high yield of well preserved hepatocytes in suspension. For light microscopic examination the separated cells may be uniformly spread on a slide glass coated with Mayer's egg albumen and stained. Electron microscopic evaluation of the dispersed cells indicated that they have intact cell membranes and retain the integrity of their cytoplasm and nuclei well. This method is most suitable for accurate determination of the nuclear content and size of individual liver cells, as well as of the number of mitotic cells, and is potentially useful for gathering other information on the morphometric cytology of the liver.

Animals↗
PubMed1975

Telemetric monitoring device to detect thrombosis in the external arteriovenous shunt.

A telemetric monitoring system of the external arteriovenous shunt for long term hemodialysis was deviced. Analysis of the arteriovenous shunt bruit showed that frequency distribution of the bruit ranged between 25 and 500 Hz. An air transmission type microphone with an optimum frequency at 200 Hz was designed. The monitoring system, including the microphone, a small FM transmitter and an FM receiver with an alarm system by the transmitter. The signals received by the FM receiver were amplified and selected by a bandpass filter. After being all-wave rectified, and averaged for one min by the averaging circuit, the signals were finally balanced by the standard signal and the precision comparator. When the arteiovenous shunt bruit ceased for more than one min, the alarm system went off. The system frequently detected obstruction of blood flow due to flection of the forearm during sleep and by other causes, thereby preventing clotting of the arteriovenous shunt flow. Thrombosis in the arteriovenous shunt was detected 5 times by the telemetric device while the patients were alseep at home, and declotting was successful in all the cases. The system has proven to be available for early detection of shunt obstruction and of clot formation inside the arteriovenous shunt.

Animals↗
PubMedDate not supplied

Greater expression of transforming growth factor alpha and proliferating cell nuclear antigen staining in mouse hepatoblastomas than hepatocellular carcinomas induced by a diethylnitrosamine-sodium phenobarbital regimen.

Transforming growth factor alpha (TGF-alpha) is a potent stimulator of normal hepatocyte proliferation, considered to have relationship to the liver regeneration or carcinogenesis. In this study, we investigated immunohistochemically the association between expression of TGF-alpha and cell proliferation activity in mouse hepatoblastomas (HBs) and hepatocellular carcinomas (HCCs) induced in B6C3F1 mice by diethylnitrosamine and sodium phenobarbital. The TGF-alpha-positive rate in HBs (29.2%) was significantly higher than that in HCCs (12.7%). Likewise, the proliferating cell nuclear antigen-positive rate (22.2%) was higher than the HCC value (14.5%). On the individual data for both TGF-alpha and PCNA, most of the HBs showed higher positive rates than HCCs. In HBs, TGF-alpha was localized only in the nuclei, whereas some HCC cells stained positive both in their nuclei and cytoplasm (0.6%). These results suggest expression of TGF-alpha and its localization might be linked to cell proliferation and play a role in malignant progression of mouse HBs.

Administration, Oral↗
PubMedDate not supplied

A new apparatus for chronic observation of the microcirculation in situ to evaluate artificial organ performance.

Chronic study of the peripheral circulation and metabolism is very important in evaluation of artificial organ performance. However, there has been no way to observe the microcirculation in situ, chronically and continuously, without restriction. In this study, the authors developed a new apparatus that could be implanted and connected to an artificial organ that would allow continuous observation of the microcirculation while the subject is awake. The apparatus uses a charge coupled device (CCD) under a new principle: thin living tissue, such as mesentery, is put directly on a highly integrated CCD and transilluminated with a light emitting diode (LED). The vascular nets in the tissue are projected onto the CCD like a contact photograph, which is sent to a television screen and can be analyzed for motion and function. A 0.5 inch CCD with 25K pixels was used in this study. The cover glass of the CCD was removed so the tissue would be able to directly contact the CCD surface. The CCD, as well as LED, were molded with hard polyurethane as electrical insulation. The apparatus is 35 mm in diameter and 10 mm high with a micro stand for lighting with the LED, which is easy to implant in a goat or calf. The resolution of this apparatus was tested by putting a micro scale on the CCD surface. Several tenths of micrometers could be seen. In an animal experiment with a rabbit, configurations of arterioles and venules and their motions could be observed continuously for a night until the electrical insulation was broken. This method might be a strong weapon in artificial organs research.

Animals↗
PubMedDate not supplied

Immunohistochemical localization of transforming growth factor alpha in chemically induced rat hepatocellular carcinomas with reference to differentiation and proliferation.

Hepatocellular carcinomas (HCCs) were induced in male Fischer 344 rats with dietary 3'-methyl-4-(dimethylamino)-azobenzene treatment and were classified into solid, glandular (well- or poorly differentiated), and trabecular types. Investigation of cell proliferation kinetics and immunohistochemical localization of transforming growth factor alpha (TGF-alpha) demonstrated all solid (n = 24) and poorly differentiated glandular type (n = 6) HCCs to have TGF-alpha-positive nuclei. Nuclear staining of TGF-alpha was also observed in 13 of 28 (46%) trabecular-type HCCs, whereas 12 (43%) exhibited cytoplasmic staining, and 3 (11%) were negative. As for well-differentiated glandular HCCs, 7 of 20 (35%) were positively stained in their nucleus, another 7 (35%) demonstrated antibody binding in the cytoplasm, and 6 (30%) were negative. The order for growth rate evaluated by bromodeoxyuridine (BrdU) labeling was solid (38.22%), poorly differentiated glandular (26.82%), trabecular (7.98%), and well-differentiated glandular (2.57%) types. For trabecular HCCs with nuclear, cytoplasmic, or negative TGF reactions, values were 13.39% (n = 13), 3.61% (n = 12), and 2.01% (n = 3), respectively. Likewise, BrdU-labeling indices for the counterpart groups of well-differentiated glandular type HCCs were 4.53, 1.91, and 1.29%, respectively. The results indicate that TGF-alpha expression might be linked to histopathological differentiation and cell proliferation in rat HCCs.

Animals↗
PubMedDate not supplied

Leptomeningeal dissemination of malignant glioma: immunohistochemical analysis of tenascin and glial fibrillary acidic protein.

Immunohistochemical expression of tenascin (TN) and glial fibrillary acidic protein (GFAP) was investigated in 9 human malignant gliomas with leptomeningeal dissemination. In these patients intracerebral glioma tissues obtained at operation and/or autopsy displayed localized expression of TN in tumor vessels and stroma. In contrast, TN was expressed in the tumor vessels, tumor stroma, and the cytoplasm of tumor cells to a high degree throughout all the leptomeningeal tumor tissues obtained at autopsy, whereas there was much less expression of GFAP in these tissues than at the primary site. These findings suggest that TN expression and decrease of GFAP expression in glioma tissue may be involved in the development of leptomeningeal dissemination.

Adolescent↗
PubMedDate not supplied

Expression of tenascin in mesangial injury in experimental glomerulonephritis.

The distribution of tenascin (TN) in the kidneys in relation to embryogenesis, the normal glomerulus and various glomerular diseases has been studied immunohistochemically. However, the existence of TN protein and mRNA simultaneously has never been reported in reversible mesangial proliferative glomerulonephritis (MPGN). In this study, by immunohistochemical methods and in situ hybridization, we investigated the expression of TN in injury to glomerular mesangial cells. Anti-Thy 1.1 mesangial proliferative glomerulonephritis was induced in Wistar rats by injection of antirat thymocyte plasma. After injection, the rats were sacrificed on days 4, 7, 10 and 14. Immunohistochemically, slight staining of TN was detected in normal glomeruli. An increase in staining was observed in the mesangial areas during the mesangial proliferative phase (days 4, 7 and 10). It decreased on day 14. Focal staining of TN in Bowman's capsule and the periglomerular region was also noted during the mesangial proliferative phase. TN mRNA could not be detected in normal glomeruli by in situ hybridization, but it was observed in the mesangial areas during the mesangial proliferative phase. Focal expression of TN mRNA was noted in Bowman's capsular epithelial cells and periglomerular cells after injection. TN mRNA-positive cells were localized to mesangial, Bowman's capsular and periglomerular areas of hypercellularity and were significantly associated with an increase in TN staining areas. In conclusion, the results of this study prove that TN is a component of the normal mesangial matrix, and that it is induced by mesangial, Bowman's capsular and periglomerular cells after mesangial injury. We could not determine the role of TN in Bowman's capsular and periglomerular areas, but a reversible MPGN model has been reported to show an irreversible progressive course in TN knockout mice. In reversible MPGN it is considered that the role of TN in the mesangial areas may be related to the process of mesangial repair.

Animals↗
PubMedDate not supplied

Development of a 3D CT-scanner using a cone beam and video-fluoroscopic system.

We describe the design and implementation of a system that acquires three-dimensional (3D) data of high-contrast objects such as bone, lung, and blood vessels (enhanced by contrast agent). This 3D computed tomography (CT) system is based on a cone beam and video-fluoroscopic system and yields data that is amenable to 3D image processing. An X-ray tube and a large area two-dimensional detector were mounted on a single frame and rotated around objects in 12 seconds. The large area detector consisted of a fluorescent plate and a charge coupled device (CCD) video camera. While the X-ray tube was rotated around the object, a pulsed X-ray was generated (30 pulses per second) and 360 projected images were collected in a 12-second scan. A 256 x 256 x 256 matrix image was reconstructed using a high-speed parallel processor. Reconstruction required approximately 6 minutes. Two volunteers underwent scans of the head or chest. High-contrast objects such as bronchial, vascular, and mediastinal structures in the thorax, or bones and air cavities in the head were delineated in a "real" 3D format. Our 3D CT-scanner appears to produce data useful for clinical imaging and 3D image processing.

Equipment Design↗