Search PubMed⌕ Search

Biomedical subjects

T Kaneda

Publications and source records attributed to T Kaneda.

At least 217 records · Page 12Linked to original sources

A Mutant of Synechococcus PCC7942 Incapable of Adapting to Low CO(2) Concentration.

Some properties of a mutant (RK1) of Synechococcus PCC7942, which requires high CO(2) for growth, are described. The photosynthetic affinity for inorganic carbon (C(i)) in RK1 was about 40 times lower than that in the wild type (WT) when grown at 3% CO(2) (H-cells) and did not change during 10 hours of exposure to low CO(2) (air containing 0.04% CO(2)). The gas exchange of WT and RK1 cells was measured using an open gas-analysis system. All the measurements were performed at a CO(2) concentration of 400 microliters per liter under the conditions where photosynthetic CO(2) fixation is inhibited. When the suspension of H-cells of WT or RK1 was illuminated, the rate of CO(2) influx from the gas phase into the suspension was low and addition of carbonic anhydrase during illumination released only a small amount of CO(2) from the medium into the gas phase. The rate of CO(2) influx and the amount of CO(2) released by carbonic anhydrase were increased in WT during low CO(2) adaptation. These changes did not occur in RK1 during exposure to low CO(2). Cytoplasmic membrane from H-cells of WT or RK1 contained small amount of 42-kilodalton polypeptide. Exposure of RK1 to low CO(2) did not have significant effect on the amount of 42-kilodalton polypeptide, while the same treatment on WT resulted in a large increase of this polypeptide. The RK1 mutant appears to be defective in its ability to utilize the intracellular C(i) pool for photosynthesis and also to transmit a low CO(2) signal for inducing the functional and compositional changes observed in WT during low CO(2) adaptation.

Journal Article↗

Gas-liquid chromatographic separation of enantiomers as their diastereomeric derivatives, illustrated with 2-methylbutyric acid.

A gas-liquid chromatographic method has been developed to separate on a small scale (acid samples as small as 2 mg) the enantiomers of 2-methylbutyric acid and to estimate a few per cent of one isomer as a contaminant in the other. Both the alpha-methylbenzyl ester and the alpha-methylbenzyl amide give a satisfactory resolution of the enantiomers. Chromatographic conditions in the order of importance are the final column temperature, the rate of temperature programming and the initial column temperature.

Butyrates↗

Distribution of 14C after oral administration of [U-14C]labeled methyl linoleate hydroperoxides and their secondary oxidation products in rats.

To study the toxicity of low molecular weight (LMW) compounds formed during the autoxidation of oils, 14C-labeled primary monomeric compounds (methyl linoleate hydroperoxides) and secondary oxidation products, i.e., polymer and LMW compounds prepared from autoxidized methyl [U-14C]linoleate hydroperoxides (MLHPO) were orally administered to rats, and their radioactive distributions in tissues and organs were compared. The polymeric fraction consisted mainly of dimers of MLHPO. For the LMW fraction, 4-hydroxy-2-nonenal, 8-hydroxy methyl octanoate and 10-formyl methyl-9-decenoate were identified as major constituents by gas chromatography-mass spectrometry (GC-MS) after chemical reduction and derivatization. When LMW compounds were administered to rats, 14CO2 expiration and the excreted radioactivity in urine in 12 hr were significantly higher than those from polymer or MLHPO administration. Maximum 14CO2 expiration appeared 2-4 hr after the dose of LMW compounds. Radioactivity of the upper part of small intestines six hr after the dose of LMW compounds was higher than the values from administered polymer or MLHPO. The remaining radioactivity in the digestive contents and feces 12 hr after administration of LMW compounds was much lower than the values observed from administered polymer or MLHPO. Among internal organs, the liver contained the highest concentration of radioactivities from polymer, MLHPO and LMW fractions, and an especially higher level of radioactivity was found in liver six hr after the administration of LMW compounds. Six hours after the dose of LMW compounds, a relatively higher level of radioactivity also was detected in kidney, brain, heart and lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Revascularization of reversed dermis grafts.

The process of vascularization and the vascular patterns in reversed dermis grafts (RDG) and full-thickness skin grafts (FTSG) in the rat were studied at various intervals after transplantation by a combination of microangiography and histologic techniques. In the early stages the RDG became vascularized more rapidly than the FTSG. However, the inflammatory reaction in the RDG persisted for longer periods than that in the FTSG in the later stages. The prolonged inflammatory reaction in the RDG was presumed to be due to the lack of epidermis for two to three weeks after surgery. Comparatively severe contraction of RDG may result from this prolonged inflammation and the delayed epithelialization.

Animals↗

Marginal vascular change in pedicle skin flaps.

The changes of vascular patterns in pedicle skin flaps were studied in rats at various intervals after operation using microangiography, with the following results: (1) Vascular change was observed in the marginal area of the flap after operation, possibly related to the release of an angiogenic factor during anaerobic metabolism. (2) Both primary and secondary revascularization were observed in the flap, but the main process was found to be primary revascularization. (3) Four days after operation, revascularization was observed. (4) Longitudinal rearrangement of the vessels in the flap could not be observed. (5) At sutured areas where the stitches remained, severe vascular reaction continued for a longer period.

Anastomosis, Surgical↗

Seasonal population changes and characterization of ice-nucleating bacteria in farm fields of central alberta.

During the summer of 1983 in central Alberta, changes in the bacterial population inhabiting the leaves of field beans (Phaseolus vulgaris L.) and canola (Brassica napus L. Altex) were studied to determine if ice-nucleating bacteria were present on these plants. Three colony types (white, yellow, and peach-colored) were found on field beans and canola leaves. Approximately 25% of the isolates from the white colony group, which dominated the population, were ice-nucleating bacteria. No ice-nucleating bacteria were present on canola leaves. Out of a total of 76 ice-nucleating bacteria isolated, 5 representative cultures were characterized in detail and identified as Pseudomonas fluorescens. The fatty acid composition of these cultures was essentially identical to that of typical P. fluorescens cultures and was altered by varying the growth temperature from 10 to 30 degrees C.

Journal Article↗

Purification and properties of NADH/NADPH-dependent p-hydroxybenzoate hydroxylase from Corynebacterium cyclohexanicum.

Crude soluble extracts of Corynebacterium cyclohexanicum, grown on cyclohexanecarboxylic acid, were found to contain 4-hydroxybenzoate 3-hydroxylase which functions with NADH as well as NADPH. The purified enzyme preparation was electrophoretically homogeneous and contained FAD as prosthetic group. The relative molecular mass of the enzyme was estimated to be about 47000 by native and denaturated acrylamide gel electrophoresis, indicating that it is monomeric. The enzyme was stable at 60 degrees C for 10 min. The enzyme was highly specific for p-hydroxybenzoate. The activity was inhibited by several aromatic analogues of p-hydroxybenzoate such as p-aminobenzoate, p-fluorobenzoate, o-hydroxybenzoate, m-hydroxybenzoate, 2,4-dihydroxygenzoate, and 2,5-dihydroxybenzoate. The Km value for NADH was fairly constant, about 45 microM, in the pH range 7.0-8.4, whereas the Km value for NADPH increased from 63 microM to 170 microM as the pH rose from 7.0 to 8.4. V values in the same pH range, however, were approximately constant in both cases; about 30 mumol min-1 mg-1 for NADH, and 26 mumol min-1 mg-1 for NADPH. Mg2+ was required for full activity of the enzyme in low concentrations of phosphate buffer. The enzyme was inhibited by C1- which was non-competitive with respect to NADH, NADPH and p-hydroxybenzoate.

4-Hydroxybenzoate-3-Monooxygenase↗

Tooth extraction in two patients who had a congenital deficiency of factor XIII.

Two cases of the extraction of deciduous teeth in unrelated patients who had congenital Factor XIII deficiency are reported. The modes of inheritance of the deficiency are discussed, and methods of screening, diagnosis, and treatment are suggested. A combination of a local hemostatic treatment and transfusion of Factor XIII concentrate resulted in the sockets healing without further postoperative bleeding in both cases.

Child↗

Multiple extractions in a patient with factor VII deficiency.

Multiple extractions were carried out in a patient with factor VII deficiency treated with prothrombin complex concentrate. Hemostasis and healing were completely satisfactory. The side effects of prothrombin complex concentrate are discussed.

Blood Coagulation Factors↗

The pectoralis major myocutaneous flap for intraoral reconstruction: surgical complications and their treatment.

The pectoralis major myocutaneous (PM-MC) flap was used for intra-oral reconstruction in 7 patients. Major necrosis did not occur in any of the cases, but minor necrosis did in two cases. In 2 cases an oro-cutaneous fistula was observed. Furthermore, in 2 cases severe facial oedema was experienced, which seemed attributable to circulatory disturbance in the part of the face where the flap was inserted. Muscle atrophy of the flap was observed in greater or lesser degree in all cases. In all cases the pectoralis major myocutaneous flap was used for the purpose of intraoral reconstruction. Intraoral reconstruction involves considerations different from transplantation in other sites. It is the purpose of this paper to present an updated review of our experience with 7 consecutive pectoralis major myocutaneous flaps, including the complications and their treatment.

Adult↗

Gene expression during terminal differentiation: dexamethasone suppression of inducer-mediated alpha 1- and beta maj-globin gene expression.

Previous studies demonstrated that hexamethylenebisacetamide (HMBA)-mediated murine erythroleukemia cell (MELC) commitment to terminal division could be suppressed by dexamethasone. A rapid (less than 2 hr) increase (step-up) in commitment to terminal cell division was observed if, after 60-70 hr in culture with inducer and steroid, MELC were transferred to medium with HMBA alone. This step-up commitment was not inhibited by actinomycin or cordycepin but was blocked by cycloheximide. In this study, we show that dexamethasone blocks HMBA-mediated activation of alpha 1- and beta maj-globin gene transcription but not the induced chromatin change characterized by appearance of DNase I-hypersensitive regions upstream from the 5' cap sites of the alpha 1- and beta maj-globin genes. A rapid (less than 2 hr) activation (step-up) of alpha 1-globin gene transcription was observed if, after 48-60 hr in culture with HMBA and dexamethasone, MELC were transferred to medium with HMBA alone. Activation of transcription of the beta maj-globin gene requires 12-24 hr of further culture. Cycloheximide inhibits step-up transcription of both globin genes. Thus, dexamethasone blocks HMBA-mediated modulation of transcription of several nonlinked genes whose expression is altered in a coordinated manner during induced MELC terminal differentiation. Further, the steroid blocks at a late step, a step after that which is rate-limiting to HMBA-mediated MELC differentiation.

Acetamides↗