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Biomedical subjects

T Higashi

Publications and source records attributed to T Higashi.

At least 433 records · Page 24Linked to original sources
PubMed1981

A rapid method for monitoring serum neutral amino acid concentrations in severe liver disease.

A rapid liquid chromatographic method for monitoring the 6 neutral amino acid levels in serum, valine, leucine, isoleucine, tyrosine, phenylalanine and methionine, has been developed for use as one of the routine clinical laboratory tests for patients with severe liver disease requiring urgent treatment. This simple method would provide much valuable information for the selection of therapy, prediction of impending coma and evaluation of the patient's response to treatment, as well as an analysis of pathophysiology and prognosis.

Amino Acids↗
PubMed1981

[The influence of whole body 60Co-irradiation on distribution of 67Ga in tumor-bearing mice (author's transl)].

Since the initial findings that 67Ga has a preferential affinity of soft tissue tumors, in humans numerous suggestions have been advanced for the basic mechanism involved. The effects produced by whole-body X-irradiation on the excretion and tissue distribution of 67Ga have been reported by Swartzendruber and others. Bradley and coworkers have shown that these irradiation effects were associated with an increase in serum iron. The present investigation was undertaken in order to study the relationships between the change in the serum iron concentration and 67Ga accumulation in the tumor and soft tissues in mice bearing Ehrlich's ascites tumor. The following results were obtained. (1) The serum iron concentration was significantly decreased between 3 and 6 hours after 10 Gy (1,000 rad) dose whole-body 60Co-irradiation. Subsequently, the serum iron levels were slowly elevated. (2) The uptake of 67GA in the tumor and soft tissues increased if the serum iron concentration was decreased by whole-body 60Co-irradiation during the early phase. On the contrary, if the serum iron concentration was high, the uptake of 67Ga in the tumor was decreased. (3) The excretion of 67Ga from the body was delayed if the serum iron concentration was decreased by whole-body 60Co-irradiation. However, if the serum iron concentration was high, the excretion of 67Ga from the body significantly increased.

Animals↗
PubMed1981

Biosynthesis of liver catalase in rats treated with allylisopropylacetylcarbamide. III. Occurrence of a possible precursor to catalase.

Inactive catalase [EC 1.11.1.6] occurring in considerable amounts in liver peroxisomal extracts from Sedormid-treated rats was investigated. The antigen-to-enzyme ratio (i.e. the ratio of catalase determined immunochemically to catalase determined enzymatically; 1.0 for purified enzyme) was around 1.7 when peroxisomal extract from Sedormid-treated rats was assayed. After dialysis of the extract against a solution containing 44 mM acetate buffer, pH 4.1, and 22% ethanol, catalase remaining in soluble from showed the same antigen-to-enzyme ratio as the purified enzyme (1.0). Moreover, the total enzymatic activity was not reduced. The results indicated that the catalase precipitated by this treatment was enzymatically inactive. The peroxisomal extract was analyzed by gel filtration, and an enzymatically inactive catalase was detected in the region corresponding to molecules smaller than the enzymatically active catalase (tetramer). When the immunoprecipitates of the inactive catalase were analyzed by polyacrylamide gel electrophoresis in the presence of SDS and urea, only a subunit (monomer) of catalase was detected. At 60 min after injection of [14C]amino acid and delta-[3H]aminolevulinic acid into rats, the specific radioactivity of 14C in this inactive catalase was 6-7 times that of active catalase. On the other hand, the 3H/14C ratio was much lower than that of active catalase. The results suggest that the inactive catalase isolated by gel filtration is an intermediate of maturation, in which apo-catalase monomer binds with heme and assembles to form complete molecules.

Animals↗
PubMed1981

[The influence of iron on 67Ga distribution in tumor-bearing mice--effect of iron administered before 67Ga injection (author's transl)].

Following its discovery by Edwards and Hayes (1969), the propensity of 67Ga to accumulate preferentially in malignant tissues has been studied at diverse levels, not only for its importance in diagnostic imaging but also for its fundamental biological interest. The biodistribution of 67Ga citrate seems to be strongly influenced by the concentration of serum iron and the unsaturated iron-binding capacity (UIBC). Recently, it was found that the clearance of 67Ga from blood and the attainment of high tumor to normal soft-tissue concentration ratios are accelerated if the serum iron concentration is high. The present investigation was undertaken in order to study the relationships between the change of the concentration of serum iron and 67Ga accumulation in the tumor and soft-tissues in mice bearing Ehrlich's ascited tumor. The following results were obtained. (1) The uptake of 67Ga in the tumor and soft-tissues except bone was decreased compared with controls if the concentration of serum iron was elevated by Fesin (saccharated ferric oxide) administered prior the injection of 67Ga. (2) The urinary excretion of 67Ga was considerably increased if the concentration of serum iron was elevated by Fesin administered prior the injection of 67Ga. The results are consistent with the hypothesis that binding 67Ga to transferrin is very important to the accumulation of 67Ga in tumor and soft tissues.

Animals↗
PubMed1981

[The influence of iron on 67Ga distribution in tumor-bearing mice--effect of iron administered after 67Ga injection (author's transl)].

Gallium-67 concentrates in a variety of soft-tissue and tumor, however the accumulation is not specific for malignant tumor. The increase the tumor to non-tumor ratio is important to improve the quality of the tumor image. It has been recently found that the clearance of 67Ga from blood and the attainment of high ratios of the tumor to normal soft-tissue concentrations are accelerated, if the serum iron concentration is high. The present investigation was, therefore, undertaken in order to study the effect of administered iron after injection of 67Ga on the accumulation of 67Ga in the tumor tissue of mice bearing Ehrlich's ascited tumor. The following results were obtained. The accumulations of 67Ga in the tumor and soft-tissues were slightly decreased compared with controls after ferric acid saccharated (Fesin) administration 3, 6 and 24 hours after injection of 67Ga. However, the tumor to blood ratio (T/B) in each group treated with Fesin was considerably increased because the clearance of 67Ga from the blood is accelerated. The large tumor to blood ratio (T/B) would be advantageous for tumor scanning.

Animals↗
PubMed1980

Computed tomography and bone scintigraphy is polyostotic fibrous dysplasia. Report of a case.

A case of polyostotic fibrous dysplasia is presented in which the extent of bony lesions was defined on the results of the CT scan and bone scan with 99m Tc polyphosphate in addition to conventional radiography. These diagnostic procedures appear to be of considerable value in defining the extent of a variety of oral-maxillofacial bony lesions. This report describes the comparative findings from 99m Tc polyphosphate bone imaging and computed tomography (CT) in one patient with polyostotic fibrous dysplasia.

Adult↗
PubMed1980

Studies on rat liver catalase. XI. Site of synthesis and segregation by stripped ER membranes.

We reinvestigated the site of synthesis of rat liver catalase, and it has been reconfirmed that catalase is synthesized not only by free polysomes but also by membrane-bound polysomes. Considerable amounts of nascent catalase on rough microsomes were released from the membrane into the medium upon incubation with puromycin, not transported directly into the intracisternal cavity of microsomes. On the other hand, catalase newly synthesized in vitro was shown to be segregated by stripped rat liver microsomal membranes in a state resistant to proteolysis. Since this segregation occurred without coupled protein synthesis, catalase appears to be transported by a mechanism different from co-translational transfer. A hypothesis is presented regarding the mechanism of intracellular transport of liver catalase.

Animals↗