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Biomedical subjects

K Tsuji

Publications and source records attributed to K Tsuji.

At least 847 records · Page 47Linked to original sources
PubMed1975

Improved high-performance liquid chromatographic method for polypeptide antibiotics and its application to study the effects of treatments to reduce microbial levels in bacitracin powder.

Improvements were made in the high-performance liquid chromatographic (HPLC) method to obtain baseline separation of chromatographic peaks of structurally similar polypeptide components in bacitracin. The improved method uses a 30-cm-long stainless-stell column packed with muBondapak C18. The theoretical plates of the column are approximately 140,000 per meter for the bacitracin A peak. The resolution function between bacitracins B1 and B2 and that between bacitracins A and B2 have been improved 418 and 225%, respectively. The components of bacitracin, bacitracins A, B, C, D, E, F, and G, were fractionated by the countercurrent distribution technique. These components, together with Compound X, a compound separated on a carboxymethylcellulose column, and bacitracin F, obtained by degrading bacitracin A sample at neutral pH, were used to identify peaks in the HPLC chromatogram. Effects of processing methods used to reduce microbial contamination levels in bacitracin powders were evaluated. Heat treatment caused a significant loss of antimicrobial activity (35% reduction), bacitracins A, B1, and B2 were reduced by 37, 22, and 21%, respectively. A significant increase (2.8 times) of bacitracin F, an oxidative degradation compound, was show. Irradiation by 60Co at 1.8 Mrad caused no loss of potency nor change in any of the bacitracin components. Ethylene oxide treatment, on the other hand, caused considerable (46%) reduction of potency. Substantial reduction of areas under the peak of bacitracins A, B1, and B2 (50, 24 and 37%, respectively) were noted. The chromatograms showed numerous unresolved peaks around bacitracins A, B1 and B2,; however, no significant increase in the bacitracin F peak, nor appearance of non-UV absorbing peaks were observed. Peptide antibiotics of the polymyxin group, circulin, colistin, and polymyxin, were also analyzed using the muBondapak C18 column with a linear-gradient elution. A UV monitor was used for polymyxin. A moving-wire flame ionization detector was used to monitor circulin and colistin. A sample of polymyxin, circulin, and colistin may be analyzed in less than 20 min of chromatographic time.

Anti-Bacterial Agents↗
PubMed1975

High-performance liquid chromatographic analysis of ampicillin.

A high-pressure liquid chromatographic method for the analysis of ampicillin is described. The method uses a 1-m long stainless steel column packed with anionic exchange resin, with a mobile phase of 0.02 M NaNO3 in 0.01 M pH 9.15 borate buffer at a flow rate of 0.45 ml/min. The degradation products of ampicillin, penicillenic and penicilloic acids of ampicillin, can be separated and quantitated in less than 12 min of chromatographic time. The relative standard deviation for the analysis of ampicillin is less than 1%, and the method is sensitive to approximately 20 ng of ampicillin/sample injected. The method was applied to the analysis of various pharmaceutical preparations of ampicillin. It is also applicable, with a slight modification, for the analysis of penicillins G and V.

Ampicillin↗
PubMed1975

Fine structural studies on the fate of "castration" cells in the rat adenohypophysis after bilateral oophorectomy.

The fate of castration cells has been studied by electron microscopy after bilateral oophorectomy. The castration cells were characterized by a large-like dilatation of rough endoplasmic reticulum which occupied almost the entire cytoplasm, and first appeared at 5 weeks after operation. Castration cells showed cellular suppression after 15 weeks of the experiment but no degenerative changes were observed at any experimental period. At the later stage of the experiment numerous secretory granules reaccumulated in the cytoplasm of the gonadotrophs and concomitantly lake-like dilatation of rough endoplasmic reticulum in some gonadotrophs gradually decreased and finally disappeared from the cytoplasm. Proportion of the castration cells and mean diameter of the largest cisterane of rough endoplasmic reticulum in each cell attained maximum value at 9 weeks after the operation; thereafter both parameters returned toward normal, although they still remained at a higher level than in controls at 18 weeks after the operation.

Animals↗
PubMed1975

Fine structural comparison of Ewing's sarcoma with neuroblastoma.

Two cases of Ewing's sarcoma and two neuroblastoma, rosette forming and round cell type, were studied electron microscopically and their fine structures were compared. The neoplastic cells of Ewing's sarcoma were characterized by aggregated glycogen particles in the cytoplasm. They had pseudopod-like cytoplasmic processes having tight junctions, which never contained microtubules or mitochondria. Ewing's sarcoma cells exhibited several stages of cell maturation and some mature cells possessed a large amount of smooth and rough endoplasmic reticulum, large Golgi complexes and numerous phagosomes containing glycogen particles as well as cytoplasmic organelles. The neoplastic cells of neuroblastoma, rosette forming type, were characterized by synaptic junctions and numerous cytoplasmic processes with production of neurites containing microtubules, neurofibrils, mitochondria and a few catecholamine granules. A few cytoplasmic processes containing mitochondria were observed even in the round cell type.

Adolescent↗
PubMed1975

Effects of dietary protein level on the energy metabolism of rats during exercise.

The experiments were designed to study the effects of exercise of various intensities in albino rats fed diets containing 8 per cent or 20 per cent casein. Male rats about 7 weeks old were divided into exercise groups and control (non-exercise) groups. The exercise groups were forced to run 57 km or 76 km in total during a 28-day period. The oxygen uptake of rats was measured in order to study the influence of exercise on energy metabolism of rats and the effects of training. Body weight and food intake were also measured. 1. In all exercise groups the total amount of food intake and body weight gain during the exercise period were smaller than those of the control groups, regardless of the protein levels of the diets. but while the rats were kept at rest after the exercise period, the food intake and body weight of these groups increased and approached those of the control groups. 2. No difference in resting metabolism was observed both in the 8 per cent and 20 per cent casein groups. At lower speeds up to 1.5 km/hr the 8 per cent casein group indicated lower oxygen requirement during the exercise but at speeds higher than 2.0 km/hr the oxygen requirement was definitely higher than that of the 20 per cent casein group. The estimated optimum speed for rats weighing 300 g on the average is somewhere between 1.5 and 2.0 km/hr is calculated on the basis of oxygen requirement for running 100 m. 3. The obvious effects of training on oxygen uptake were seen in the 20 per cent casein group after four weeks' training, although no effect was found in the 8 per cent casein group.

Animals↗