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Biomedical subjects

T Komai

Publications and source records attributed to T Komai.

At least 91 records · Page 5Linked to original sources
PubMed1980

Radioiodinated estrogen derivatives.

Monoiodohexestrol exhibits 10 to 15% specific binding to the 8S estrogen receptor while the remainder binds to nonreceptor 4S proteins. Reduction of nonreceptor binding with either thyroxine or 8-anilino-1-naphthalene sulfonic acid was not quantitative. Thus no accurate determination of the concentration of receptor sites in the radioreceptor assay was possible by graphical analysis. Two additional estrogens--17 alpha [125I]iodoethynylestradiol and 17 alpha-[125I]iodoethynyl-11 beta-methoxy estradiol--were synthesized at high specific activity. Although the iodoethynyl derivatives were stable under synthetic conditions, deiodination in the presence of proteins is too fast to allow either in vivo or in vitro use. To make these compounds clinically useful, therefore, chemical modification to reduce nonreceptor binding and the rate of dehalogenation must be undertaken.

Anilino Naphthalenesulfonates↗
PubMed1978

Fibrinolytic enzyme in the lining walls of chronic subdural hematoma.

Active plasmin, available plasmin, and total plasminogen were measured by Enzo-diffusion fibirn plate techniques in 11 cases and level of tissue activator and tissue fibrinolytic activities in another 11 cases with chronic subdural hematoma. The values were too small to be measured in some instances. Anti-plasmin in the hematoma was less than in the blood plasma. The outer membrane contained about three times more tissue activator than the dura mater, although the inner membrane contained none. Increased tissue activator, which exudes from the extremely vascular outer membrane, transforms plasminogen into plasmin in subdural hematoma, so that plasmin breaks down fibrin and fibrinogen and induces continuous hemorrhage.

Dura Mater↗
PubMed1977

Estrogen derivatives for the external localization of estrogen-dependent malignancy.

Four radioiodinated estrogen derivatives were studied to determine their affinity for the estrogen-binding protein found in the cytosol of rabbit and rat uteri. In vitro determination of the binding properties by competitive-binding experiments and by sucrose-gradient centrifugation indicates that one of the derivatives, iodohexestrol, binds to the cytosol estrogen-binding protein. This in vitro behavior was related to in vivo distribution. Studies in immature female rats showed high uterine uptake of iodohexestrol at 2 hr (1.69% dose/gm). Iodohexestrol also has a high nonspecific binding in both the blood and the uterine cytosol. Thyroxine can diminish the nonspecific binding in vitro; in vivo the prior injection of thyroxine increased the 2-hr uterus-to-blood ratio from 1.9 to 10.4 The in vitro receptor-assay system was helpful in predicting in vivo distribution.

Animals↗
PubMed1976

Role of local hyperfibrinolysis in the etiology of chronic subdural hematoma.

The authors describe studies performed on material aspirated from chronic subdural hematomas. Patients were given 51Cr-labeled red cells prior to aspiration, and it was possible to demonstrate that the mean daily hemorrhage into the hematoma space amounted to 10.2% of its volume. Immunoelectrophoresis of the aspirated hematoma fluid by monospecific anti-human fibrinogen revealed the presence of fibrin and fibrinogen degradation products that, measured by hemagglutination-inhibition immunoassay techniques, varied between 5.0 and 10,500 mug/ml with an average of 2604 mug/ml in 18 cases. The tissue activator was demonstrated by Todd's histological localization in the outer membrane of the chronic subdural hematoma in 11 cases, but not in the inner membrane. These results indicate that if a clot in the subdural space causes the formation of neomembrane, and excessive fibrinolysis occurs, the subdural clot would not only liquefy, but also enlarge by continuous hemorrhage from the neomembrane. Therefore, local hyperfibrinolysis and continuous bleeding are important in the etiology of the chronic subdural hematoma.

Cerebral Hemorrhage↗
PubMed1976

Iodinated bleomycin: an unsatisfactory radiopharmaceutical for tumor localization.

Cobalt-57-bleomycin is a clinically useful tumor-localizing agent, but attempts to label bleomycin (BLEO) with other radionuclides have been made because of the long physical half-life of 57Co. As an alternative labeling approach, we iodinated BLEO both directly on the imidazole ring and indirectly by reaction with N-succinimidyl 3-(4-hydroxy, 3-iodophenyl) propionate. Directly iodinated BLEO retained antibacterial activity, but in tumor-bearing rats it showed a lower tumor-to-blood ratio (2.3) at 2 hr than did 57Co-BLEO (11.8). The antibacterial activity of the indirectly labeled BLEO was markedly reduced and this material showed a tumor-to-blood ratio of 0.55 at 2 hr. The radioiodinated bleomycins are not suitable substitutes for 57Co-BLEO as tumor-imaging radiopharmaceuticals.

Adenocarcinoma↗
PubMed1975

The binding of kasugamycin to the Escherichia coli ribosomes.

The binding of kasugamycin to the E. coli ribosomes has been demonstrated by equilibrium dialysis. Kasugamycin binds to the 70S ribosomes in a molar ratio of 1:1. The association constant is approximately 6 X 10(-4) M-1. The antibiotic binds to the 30S subunit as well as to 70S ribosomes, but only slightly to the 50S subunit. The binding of kasugamycin is not significantly affected by the presence of other aminolgycoside antibiotics: streptomycin, kanamycin. or gentamicin. Kasugamycin does not bind to ribosomes derived from a kasugamycin-resistant mutant, ksgC.

Aminoglycosides↗