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Biomedical subjects

T Okabe

Publications and source records attributed to T Okabe.

At least 469 records · Page 26Linked to original sources

Suppressive effect of bradykinin to cellular immune responses in vivo and in vitro.

Bradykinin, as well as histamine, one of the mediators in IgE mediated immediate type allergic reactions or acute inflammation, may affect the in vitro and in vivo cell-mediated immune reactions of the immunized animals. It was demonstrated in our present experiment that the appearance of delayed type hypersensitivity (DTH) skin reaction in the immunized guinea pig was remarkably suppressed by treatment of bradykinin or histamine and the suppression of cutaneous DTH by bradykinin was inhibited by H-2 antagonist (burimamide) but not by H-1 receptor blocker (chlorpheniramine). It was also clearly demonstrated that bradykinin suppressed the production of antigen-induced macrophage migration inhibitory factor (MIF) of the immune guinea pig peritoneal exudate cells (PECs) and the production of MIF was blocked by H-2 antagonist (burimamide) or H-2 agonist (tolazolin) but not by H-1 antagonist (chlorpheniramine). Antigen-induced lymphocyte proliferation of the immunized mice, one of the indicators of the cellular immune response, was also suppressed by treatment of bradykinin. These results indicate that bradykinin as well as histamine may have some role in the subsequent expression of cellular immune reactions.

Animals↗

Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures.

Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements.

Adult↗

Stable xenon CT cerebral blood flow measurements computed by a single compartment--double integration model in normal aging and dementia.

Programs have been developed, using a single compartmental analysis model, that provide rapid computer derivation for values of both local cerebral blood flows (LCBF) and local tissue: blood partition coefficients (L lambda) using inhaled stable xenon gas (Xes) as the indicator. These programs are planned for utilization of raw data points derived from serial computed tomography scans made between the 3rd and 9th min after 35% Xes inhalation, while concentrations of end-tidal Xes (PEXes) are concurrently monitored. Double integration and least squares fitting permitted estimation of corresponding arterial (assumed from PEXes) and tissue Xes concentrations at each scanning interval during Xes saturation. Derived estimates for L lambda and LCBF values for each region of interest mathematically approximate values saturated to infinity. The method described can be utilized for any freely diffusible indicator. Cross-sectional analysis of results obtained in 13 normal healthy volunteers between 20 and 80 years of age showed no age-related changes in L lambda values but progressive decreases in blood flow of cortex, basal ganglia, and white matter with advancing age. In senile dementia of Alzheimer's type (SDAT, n = 8) L lambda values were likewise found to be unchanged, but cortical and thalamic gray matter LCBF values were significantly reduced compared to age-matched normal volunteers.

Adult↗

Erythrocyte aging changes evaluated by the deoxyuridine suppression test.

Many hematologic studies have shown that the erythrocyte count decreases while the size of the individual cell increases in the aged. This study was performed in order to (1) evaluate changes in the blood erythrocyte level and mean erythrocyte size in the elderly and (2) evaluate use of the deoxyuridine (dU) supression test to determine whether deficiency of vitamin B12 or folate plays any role in age-related changes of hematopoiesis. Selected for study were 102 healthy men whose ages ranged from 20 to 79 years. The erythrocyte count and hemoglobin level decreased significantly, whereas the mean corpuscular volume and mean corpuscular hemoglobin increased after 70 years of age. Fresh bone-marrow cells were obtained from 10 young (20-38 yr) and 10 aged (70-82 yr) men. Wickramasinghe's dU suppression test was modified by application of an automatic cell harvester. The results were normal in both groups. Thus, the route of dU to dTMP in a DNA synthetic pathway appeared intact, and there was no evidence of B12 or folate deficiency in the aged to explain the observed macrocytosis. However, 3H-thymidine uptake by nucleated bone-marrow cells was significantly decreased, and the ratio of 3H-uridine to 3H-thymidine uptake was greater in the old group than in the young group. These results could be explained by altered nucleic acid metabolism (unbalanced cell growth) or by a change in the proportion of the different fractions of nucleated cells.

Adult↗

New plastic joints for plastic orthoses.

Plastic joints for orthoses have more advantages than metal joints. They are lightweight, noiseless comfortable to use, rust proof, corrosion free, and radiolucent. Two types of plastic joints were developed by the authors, one for the ankle joint and the other for the knee joint, elbow joint or hip joint. Polypropylene was chosen as the joint material because of its appropriate flexibility and toughness.

Ankle Joint↗

Cadeguomycin, a noval nucleoside analog antibiotic. I. The producing organism, production and isolation of cadeguomycin.

An actinomycete strain IM7912T was found to produce cadeguomycin, a new nucleoside analog antibiotic, together with tubercidin. Morphological, cultural and physiological studies showed that the organism belongs to the species Streptomyces hygroscopicus. Comparisons with S. hygroscopicus ISP 5578 revealed that both strains possess similar characteristics except for production of yellow or brownish yellow soluble pigment in some media. Cadeguomycin was isolated from the culture filtrate, separated from tubercidin, and purified.

Anti-Bacterial Agents↗

Cadeguomycin, a novel nucleoside analog antibiotic. II. Improved purification, physicochemical properties and structure assessment.

Cadeguomycin, a new nucleoside analog antibiotic, has been purified as colorless needle crystals by recycling preparative HPLC. The antibiotic, C12H14O7N4, mp 231 approximately 239 degrees C (dec.), FD-MS: m/z 326 (M+); is a weakly acidic substance, showing UV gamma H2Omax (epsilon) 232 (19677), 272 (6881) and 298 nm (7607), and IR nu KBrmax 1650 (C = O) and 3420 (NH or OH) cm-1. The UV spectrum is similar to other pyrrolo[2,3-d]pyrimidines. The structure of cadeguomycin, 2-amino-3,4-dihydro-4-oxo-7-beta-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine-5- carboxylic acid, has been elucidated by 1H NMR and 13C NMR in comparison with other pyrrolo[2,3-d]pyrimidines and their nucleosides.

Anti-Bacterial Agents↗

Establishment and characterization of a human colony-stimulating factor-producing cell line from a squamous cell carcinoma of the thyroid gland.

A human colony-stimulating factor (CSF)-producing cell line, T3M-5, has been established in vitro from a squamous cell carcinoma of the thyroid gland transplanted into athymic nude mice [congenitally athymic BALB/c (nu/nu) mice; Central Institute for Experimental Animals, Kawasaki, Japan]. Contaminating fibroblasts derived from a host nude mouse were eliminated by treatment with antiserum raised against nude mouse cells. T3M-5 cells have been continuously propagated during 3 years. The cells grew in a monolayered sheet with about 22 hours of population-doubling time and showed about 40% plating efficiency. The cells exhibited an epithelium-like morphology resembling the structure of the original tumor and showed tumor takes when inoculated into nude mice. Chromosome analysis revealed the cell line to be a human aneuploid line with a hypertriploid mode. The cells possessed the characteristic function of human CSF production in vitro and produced marked neutrophilia in tumor-bearing nude mice that were inoculated with the cultured cells. The molecular weight of the CSF was estimated at about 27,000 and was stable over the pH range 1.0-9.0 at 4 degrees C for 21 hours. The CSF activity was destroyed by either trypsin or chymotrypsin, but it resisted neuraminidase, DNase, and RNase. The cells could be well propagated in roller bottles. About 100 liters of the conditioned medium was obtained with the roller bottle culture method, which formed approximately 500,000,000 colonies of human bone marrow cells. The rate of recovery of CSF activity from the gel-filtration column was high (68.9%). This cell line is therefore expected to aid in the large-scale preparation of human CSF.

Aged↗

Superoxide dismutase in various tissues from rabbits bearing the Vx-2 carcinoma in the maxillary sinus.

Distribution profiles of superoxide dismutase isoenzymes in various tissues of rabbits with the Vx-2 carcinoma in the maxillary sinus were compared with those of control rabbits. Copper- and zinc-containing superoxide dismutase (Cu,Zn-SOD) activity in the liver of rabbits decreased significantly 3 weeks after transplantation. Manganese-containing superoxide dismutase (Mn-SOD) activity did not decrease significantly within 5 weeks after transplantation. In other tissues from the tumor-bearing rabbits, Cu,Zn-SOD and Mn-SOD activities were not changed within 5 weeks. No Mn-SOD activity and low Cu,Zn-SOD activity were detected in the Vx-2 carcinoma. These results suggest that the Vx-2 carcinoma has lost most of its ability to defend against oxygen toxicity and this ability decreased only in the liver of rabbits bearing the Vx-2 carcinoma in the maxillary sinus.

Animals↗