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Biomedical subjects

T Shibata

Publications and source records attributed to T Shibata.

At least 973 records · Page 54Linked to original sources
PubMed1985

Time-dependent cytotoxic action of human recombinant alpha-interferon (Ro22-8181) in vitro and the sensitivity of various cultured leukemia and lymphoma cell lines to it.

The growth inhibitory activity of human recombinant leucocyte A interferon (Ro22-8181: alpha-interferon) against 23 human cultured cell lines derived from leukemias and lymphomas was measured quantitatively by regrowth assay. Daudi cells were the most sensitive to it. Two T-cell lines (RPMI-8402, HUT78), three B-cell lines (Raji, Ly16, A3/Kawakami), one non-T, non-B acute lymphoblastic leukemia (ALL) cell line (KOPN-1) and three myelomonocytoid cell lines (U937, THP-1, ML-1) were moderately or slightly sensitive. Although the levels of sensitivity of these cell lines were different, cells could be killed by the recombinant alpha-interferon. Morphological changes in the sensitive cells treated with it were decreases in mitosis, pyknosis and fragmentation of the cells. Thirteen other cultured cell lines were not sensitive. The results indicated that the growth inhibitory activity of recombinant alpha-interferon is not always cell lineage-specific. There were only three cell lines whose sensitivity, expressed by the concentration required for 90% growth inhibition, was less than the several hundred units per milliliter that has usually been obtained as blood levels in clinical trials. These three included one of 10 T-cell lines and two of seven B-cell lines; none of six non-T, non-B ALL and myelomonocytoid cell lines were that sensitive. Among virus-associated cell lines, only Epstein-Barr virus-associated B-cell lines were sensitive to the interferon; adult T-cell leukemia virus-associated T-cell lines were not sensitive. It was demonstrated that recombinant alpha-interferon has a time-dependent, but not a concentration-dependent cytocidal action, indicating that optimal therapeutic schedules of recombinant alpha-interferon for cancer may be daily long-term treatment, not single or short-term large-dose therapy.

Antineoplastic Agents↗
PubMed1985

[Posttraumatic aneurysm-like shadow at the supraclinoid portion of the internal carotid artery--a case report].

Traumatic cerebral aneurysms occupy less than 1% in all cerebral aneurysms and the onset usually occurs two to three weeks after the head injury. The authors present a case revealing an aneurysm-like shadow at the supraclinoid portion of the internal carotid artery immediately after the head injury. A 45-year-old man was admitted in a semi-comatose state, with bleeding from the nose and the ear. He presented anisocoria, with the left pupil larger, and absence of light reflex of the pupil. Roentgenographic examinations revealed fractures of the skull, the left radius, and the pelvis. CT disclosed subarachnoid hemorrhage and intrasylvian and intracerebral hematoma, with midline shift to the right. Left carotid angiograms revealed an aneurysm-like shadow projecting medially at the supraclinoid portion of the left internal carotid artery, and an emergency operation was performed. A left fronto-temporo-parietal craniectomy was done. Incision of the dura disclosed a thin subdural hematoma and subarachnoid hemorrhage on the surface of the brain. Following removal of the intrasylvian and intracerebral hematoma and slight retraction of the left frontal lobe, a bone fracture and dural tear of the anterior cranial fossa were found. During exposure of the internal carotid artery, a heavy bleeding occurred from the supraclinoid internal carotid artery. Under control of the bleeding by temporary clipping of the internal carotid artery, the bleeding point was proved to be a longitudinal tear of the infero-medial wall of the internal carotid artery, and its length was about 5 mm. Because it was difficult to suture the tear, the internal carotid artery was doubly clipped.(ABSTRACT TRUNCATED AT 250 WORDS)

Aneurysm↗
PubMed1985

Human ductus arteriosus. A histological study on the relation between ductal maturation and gestational age.

The present study deals mainly with the ductus arteriosus of preterm infants of gestational age less than 29 weeks, birth weight less than 1200 g, and postnatal age less than 72 hours. Excised ductus were histologically examined postmortem and compared to those of infants of more advanced gestational age. Intimal cushion and duplication and/or interruption of the internal elastic lamina of the ductus arteriosus were employed as the indicators of the maturation of the ductus arteriosus. The ductus arteriosus of infants with gestational age more than 29 weeks showed histologically more mature features than those of 28 weeks or less. It is considered that there is a relation between gestational age and histologic maturation of the ductus arteriosus.

Aorta↗
PubMed1984

On the nucleotide sequence recognized by a eukaryotic site-specific endonuclease, Endo.SceI from yeast.

Endo.SceI which is isolated from cells of Saccharomyces cerevisiae is a eukaryotic site-specific endonuclease active on double-stranded DNA. At each cleavage site, Endo.SceI cuts only a defined phosphodiester bond in each strand of the double helix. We compared nucleotide sequences around five cleavage sites for Endo.SceI using a computer. We could not find any common specific sequence consisting of five base pairs or more among them. However, we found a 26-base pair consensus sequence which included 15 conserved nucleotides, allowing any of the five sequences to include a few nucleotides deviated from the consensus sequence. The consensus sequence is 5'-CAn*PYnnAnnCYYGTTnnnPnYnnYA-3', where P, Y, n, and * denote purine, pyrimidine, any nucleotide, and the center of the cleavage site, respectively. The numbers of sites at which the consensus sequence appears in pBR322 DNA, phi X174 replicative form DNA, fd replicative form DNA, or SV40 DNA are close to those of the cleavage sites for Endo.SceI. We found that a 33-base pair fragment was efficiently cut at the defined phosphodiester bonds by Endo.SceI. This 33-base pair fragment included 25 base pairs out of the 26-base pair consensus sequence. The fragments in which a part of the consensus sequence was missing were not cut by Endo.SceI. These observations suggest that the consensus sequence described above is the major characteristic around the cleavage sites recognized by Endo.SceI and that the mode of recognition of cleavage sites by Endo.SceI is different from that by restriction endonucleases. We found homology between the consensus sequence for Endo.SceI and the sequences around the cleavage sites for two other site-specific endonucleases of S. cerevisiae: Endo.SceII and YZ-Endo which is involved in mating type switching.

Base Composition↗
PubMed1984

Transient length responses of heart muscle in Ba2+-contracture to step tension reductions.

The transient length response of the cat papillary muscle in Ba2+-contracture to step tension reduction was found to comprise four different phases. It is tentatively suggested that the transient response is mostly determined by the kinetics of the attachment and detachment of cross-bridges between actin and myosin filaments, which vary appreciably with activation level of the muscle.

Animals↗
PubMed1984

Pancreatic immunoreactive somatostatin and diabetes mellitus.

Pancreatic secretions were collected during endoscopic retrograde cholangiopancreatography from 15 subjects without pancreatic, biliary, or hepatic diseases, 11 patients with non-insulin-dependent diabetes, and 11 patients with insulin-dependent diabetes. Pancreatic secretion was stimulated by the intravenous administration of one unit of secretin per kilogram of body weight. Immunoreactive somatostatin (IRS) in the pancreatic juice of the nondiabetic subjects ranged from 43 to 97 pg/ml, in non-insulin-dependent diabetics from 5 to 3872, and in the insulin-dependent diabetics from 0 to 2093. IRS in insulin-dependent diabetics under good plasma glucose control ranged from 0 to 281 pg/ml, compared to those under poor control who ranged from 518 to 2093 pg/ml. These results indicate that IRS in pancreatic juice is higher in poorly controlled insulin-dependent diabetics than in well controlled insulin-dependent diabetics and nondiabetics. Whether these changes in IRS are purely secondary phenomena or play some pathogenetic role in the disturbed metabolism of diabetes remains to be proven. The chromatographic profile of IRS in pancreatic juice on both gel filtration and high-performance liquid chromatography has indicated that these IRS moieties represent somatostatin 14 and somatostatin 28.

Adult↗
PubMed1984

Long-term follow-up examination of experimental cataracts in rats by Scheimpflug photography and densitometry.

Development of experimental cataract can be objectively monitored in rats by application of Scheimpflug photography with the SL 45 Topcon camera and subsequent densitometric image analysis. The method has been used to study naphthalene cataract in Brown-Norway rats (BN-CPB), as well as diabetic cataract induced by streptozotocin injection in Sprague-Dawley rats. The values obtained by linear microdensitometric image analysis allowed precise characterization of the opacification with respect to size, topography, and time progress so that statistical evaluation of the efficacy of certain drugs in prevention or delay of experimental cataracts was possible.

Animals↗
PubMed1984

The excretion of dimethadione in pure pancreatic juice and bile in postoperative patients.

The excretion of dimethadione (DMO) in pure pancreatic juice and bile was studied in postoperative patients undergoing external drainage of pancreatic juice and in those who had undergone percutaneous transhepatic cholangiodrainage. During and after oral administration of trimethadione, which is the precursor of DMO, pancreatic DMO concentration closely paralleled plasma DMO concentration. Pancreatic juice/plasma concentration ratio for DMO exceeded 1.0. In a patient with a large pancreatic cyst communicating with the main pancreatic duct, pancreatic DMO concentration after single rapid injection of secretin inversely correlated with the flow rate, while its output depended directly on the rate. Biliary DMO output after secretin injection was closely dependent on the flow rate, but was extremely low. The present results are essentially compatible with the findings previously observed in dogs.

Adult↗
PubMed1984

Multiple hemangioblastomas accompanied by syringomyelia in the cerebellum and the spinal cord.

The present report covers an autopsied case of multiple hemangioblastomas in the cerebellum and the spinal cord, which did not involve the retinas and other organs. An intramedullary hemangioblastoma was found at the C3-4 level of the spinal cord and similar small tumors were present at the C-7 and Th-4 levels. Multiple cysts were located from the C1-2 to the lumbar level; some of these seemed to be longitudinally continuous, like syringomyelic cavities. These findings appear only rarely in published reports of autopsied cases of hemangioblastomas in the spinal cord.

Adult↗
PubMed1984

[Biometry of the lens with respect to age and cataract morphology. Evaluation of Scheimpflug photos of the anterior segment].

Thickness of the lens, cortex and nucleus or nucleus with supranuclear layer, respectively, were determined for 58 controls aged 11-69 years (115 lenses), and for 175 patients aged 30-86 years with different types of cataract (247 lenses). Measurements of the densitograms of Scheimpflug photos (taken along the optical axis, magnified 10-fold) were performed, accurate to 0.5 mm (corresponding to 0.05 mm original size). The cataractous lenses were grouped in 5 morphological classes and 3 degrees of opacification (density according to the Scheimpflug photos). As regards normal lenses, the present authors' findings correspond to earlier findings of Niesel et al. (1976). Deviations from the normal pattern are found in typical cortical cataract (water-cleft and spokes cataract, wedge-shaped cataract) where nucleus and nucleus with supranuclear layer are thinner than the normal lenses, while with nuclear cataracts and mixed types the opposite is the case. In eyes with posterior cortical opacities no increase in the thickness of the anterior cortex is found with aging. With the true nuclear cataracts the increase in the thickness of the anterior cortex is negligible. The degree of opacification is closely related to an increase in the thickness of the nucleus and supranuclear layer, which implies a decrease in the thickness of the anterior cortex. Water-clefts and spokes of larger size cause the anterior cortex to become thinner. In eyes with wedge-shaped cataracts the different degrees of opacification did not affect the parameters measured.

Adolescent↗