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Biomedical subjects

S Toda

Publications and source records attributed to S Toda.

At least 163 records · Page 9Linked to original sources
PubMed1988

A pulsatile pump for cardiopulmonary bypass and its clinical use.

A pulsatile pump driven by a coil spring, which was designed and constructed by us, is described in this report. It consists of two main parts, a disposable blood chamber and a driving section. The blood chamber has two leaflet valves and a piston, which is covered with two bellofram rolling diaphragms and moves into the housing to draw in and eject the blood. The driving section consists of three cams, an electric motor and a coil spring. The ejection force is wholly produced by the compressed coil spring and is transmitted to the piston in the blood chamber by a rod. This pump allows the ejection pressure, the beat rates, and the stroke volume all to be changed independently. The performance of the pump was tested by using a circulation model where the beat rate was adjusted from 30 to 250 bpm. The output subsequently increased from 0.8 l/min to 5.7 l/min and the stroke volume, from 20.4 ml to 36.7 ml. This new pump has been used for clinical cardiopulmonary bypasses in 24 patients of open heart surgery and the pressure traces during perfusion resembled those of the patients' own hearts.

Child↗
PubMed1988

Effects of the Chinese herbal medicine "saiboku-to" on histamine release from and the degranulation of mouse peritoneal mast cells induced by compound 48/80.

The herbal medicine "Saiboku-to" (ST) has been used for the treatment of bronchial asthma. ST was found to inhibit histamine release from and the degranulation of mouse peritoneal mast cells induced by compound 48/80. Its inhibitory effects were concentration-related and somewhat weaker than disodium cromoglycate, a known inhibitor of histamine release and mast cell degranulation. From these results, ST could appear to be useful in the treatment of Type I allergic reactions.

Animals↗
PubMed1988

Conformational properties of the guanine-binding site of ribonuclease T1 inferred from the X-ray structure and protein engineering.

Recognition by ribonuclease T1 of guanine bases via multidentate hydrogen bonding and stacking interactions appears to be mediated mainly by a short peptide segment formed by one stretch of a heptapeptide, Tyr42-Asn43-Asn44-Tyr45-Glu46-Gly47- Phe48. The segment displays a unique folding of the polypeptide chain--consisting of a reverse turn, Asn44-Tyr45-Glu46-Gly47, stabilized by a hydrogen-bond network involving the side chain of Asn44, the main-chain atoms of Asn44, Gly47 and Phe48 and one water molecule. The segment is connected to the C terminus of a beta-strand and expands into a loop region between Asn43 and Ser54. Low values for the crystallographic thermal parameters of the segment indicate that the structure has a rigidity comparable to that of a beta-pleated sheet. Replacement of Asn44 with alanine leads to a far lower enzymatic activity and demonstrates that the side chain of Asn44 plays a key role in polypeptide folding in addition to a role in maintaining the segment structure. Substitution of Asn43 by alanine to remove a weak hydrogen bond to the guanine base destabilized the transition state of the complex by 6.3 kJ/mol at 37 degrees C. In contrast, mutation of Glu46 to alanine to remove a strong hydrogen bond to the guanine base caused a destabilization of the complex by 14.0 kJ/mol. A double-mutant enzyme with substitutions of Asn43 by a histidine and Asn44 by an aspartic acid, to reproduce the natural substitutions found in ribonuclease Ms, showed an activity and base specificity similar to that of the wild-type ribonuclease Ms. The segment therefore appears to be well conserved in several fungal ribonucleases.

Amino Acid Sequence↗
PubMed1988

Testicular tumors in non-twin brothers from a consanguineous marriage.

Malignant testicular tumors occurring in non-twin brothers are reported. Both of the brothers suffered from amentia and epilepsy and were the product of a consanguineous marriage. One brother presented with teratocarcinoma and the other seminoma. With a review of the literature, genetic roles in the etiology of testicular neoplasia are discussed.

Adolescent↗
PubMed1988

An electron microscopic study of the acupuncture or moxibustion stimulated regional skin and lymph node in experimental animals.

Ultrastructures of the electro-acupuncture or moxibustion stimulated skin and regional lymph nodes in experimental animals were examined by scanning and transmission electron microscopy. In the scanning electron microscopy, small numbers of infiltrating erythrocytes and lymphocytes were found in the vicinity of the penetrated acupuncture needle in the acupuncture-stimulated skin, whereas moxibustion-treated instances revealed a large number of immunocyte infiltrations in the region. Transmission electron microscopically revealed that immunocytes consisted of lymphocytes, monocytes and some granulocytes and mast cells. In addition, the moxibustion-stimulated regional lymph nodes increased in weight after the stimulation and induced numerous immunocyte influx through afferent lymphatics. The acupuncture-stimulated nodes, however, revealed no remarkable change in the weight and morphology. A functional significance of the acupuncture and moxibustion-stimulated skin and regional nodes was discussed in reference to previous immunohistological descriptions of immune-reacted lymph node of the same animals.

Acupuncture Therapy↗
PubMed1988

[A case of cystic changes in a giant leiomyoblastoma of the stomach].

A 44-year-old male was admitted to hospital with a complaint of abdominal distention. A CT scan revealed a giant multicystic mass in the abdominal cavity, a tumor that measured 34 cm in diameter, which had risen from the gastric body and grew in an exophytic fashion with a stalk. Histologic findings exhibited a malignant leiomyoblastoma with cellular pleomorphism and a intracytoplasmic cystic change, which included disseminated nests of immature small round cells. After excisional surgery, the patient has had no sign of a recurrence for the past two years.

Adult↗
PubMed1988

An electron microscopical observation of the endoneurial mast cells of the laboratory musk shrew: Suncus murinus).

Histochemical and ultrastructural properties of endoneurial mast cells of the normal and histamine liberator Compound 48/80 (48/80)--injected musk shrew, Suncus murinus (Suncus) were examined by light and electron microscopies. It was observed that the normal mast cells contained numerous cytoplasmic granules, with dense and irregular dense cores, covered at times with slender microvilli. The cells were diffusely located within the endoneurial sheath of the peripheral nerve fibers and in the intercellular spaces of the spinal ganglion cells. Histochemically, histamine, 5-hydroxytryptamine and heparin were observed in mast cell granules. Biochemical analysis also indicated a relatively high content of histamine in the suncus peripheral nerve. A single intradural-injection of 48/80 resulted in the degranulation of endoneurial mast cells and revealed peculiar axoplasmic changes make up of neurofilament-mitochondrial complexes in the peripheral nerve fibers. No remarkable histochemical and ultrastructural differences were observed between the endoneurial mast cells and the connective tissue mast cells in the suncus. The significance of these findings is discussed with regard to previous studies of the endoneurial mast cells in other laboratory animals.

Animals↗
PubMed1988

Unilocular fat cells in three-dimensional collagen gel matrix culture.

Three-dimensional culture with collagen gel, developed recently for the in vitro study of some mammalian cells in a more physiological condition than a monolayer culture, was applied for a biological study of unilocular fat cells. Successfully embedded in the gel, the unilocular fat cells were shown to be able to keep their cellular function and actively proliferate. These findings confirm that unilocular fat cells do undergo proliferation under in vitro conditions as demonstrated in monolayer culture.

Adipose Tissue↗
PubMed1987

Endothelial cell tumors develop in transgenic mice carrying polyoma virus middle T oncogene.

Inoculation of newborn mice with the murine polyoma (Py) virus leads to tumor formation in a wide range of tissues. In order to investigate viral oncogenesis, we generated transgenic mice carrying either the Py large T antigen (LT) gene or the Py middle T antigen (MT) gene linked to Py early region regulatory sequences. While Py LT mice exhibit no phenotype, Py MT mice develop multifocal tumors of the vascular endothelium. These hemangiomas are lethal to the animals and can be passaged in vivo. Transgene RNAs and protein are present in both hemangiomas and the testes of these mice, and the Py middle T protein in both tissues is complexed to a cellular tyrosine kinase. The expression of complexed middle T protein in both tumorigenic endothelial cells and unperturbed testes implies that endothelial cells may be particularly susceptible to the action of the middle T oncogene. These observations indicate that Py middle T disrupts the normal strict controls on vascular growth, and suggest that Py MT transgenic mice will provide a model for studying the control of angiogenesis.

Animals↗
PubMed1987

Proliferation of unilocular fat cells in the primary culture.

Mature white fat cells (unilocular fat cells) have generally been considered to be in terminal differentiation and, hence, to have no proliferative ability. A new method, referred to as "ceiling culture," has been devised in our laboratory to culture unilocular fat cells in vitro. Under such culture conditions, the fat cells continue to exhibit specific functions of lipid metabolism and proliferate extensively. Intracytoplasmic lipid droplets did not inhibit division of the cells. There were two modes of proliferation of unilocular fat cells: "loculus-dividing" cell division, in which the single loculus of fat in the dividing cell was broken down into multiple droplets and distributed evenly between the daughter cells, and "loculus-preserving" cell division, in which the loculus in the dividing cell was minimally broken down and inherited with its shape preserved by one of the daughter cells with the other getting only a small number of fine lipid droplets. Such findings suggest that unilocular fat cells in mature fat tissue in vivo are probably capable of proliferation in such modes under some conditions.

Adipose Tissue↗
PubMed1985

[Treatment of small liver cancer].

Histopathological studies were conducted on the resected lesions in eight cases of small liver cancer, and therapeutic methods are discussed. Examinations revealed tumor cell infiltration into the fibrous capsule in 5/7 (71%), into extracapsular tissues in 3/7 (43%), and vascular invasion by tumor cells in 2/8 (25%) cases. Seven patients were complicated with liver cirrhosis and one patient with hepatic fibrosis. On the basis of preoperative TAE performed in three cases and studies on the resected indicating that tumor cells remained that have infiltrated into extracapsular areas, resection was considered to be necessary to attain radical cure. At 100%, the one-year survival rate was encouraging. However, two cases of recurrence would suggest that further studies are necessary on areas to be resected.

Aged↗