Search PubMed⌕ Search

Biomedical subjects

M Fujimura

Publications and source records attributed to M Fujimura.

At least 181 records · Page 10Linked to original sources
PubMed1979

Spontaneous regressive epitheliomas in the Japanese newt, Cynops pyrrhogaster.

Spontaneous tumors in urodele amphibians have been considered uncommon, and this resistance has sometimes been associated with the natural regenerative capacity of tissues in such species. This report describes spontaneous, nonpigmented, benign epitheliomas which were found in 44 of 1586 (2.8%) adult newts, Cynops pyrrhogaster, captured in central Japan. Both sexes were affected equally, usually with single tumors occurring at any epidermal site. Under laboratory conditions, these large tumors rapidly regressed or disappeared. Lesions were histologically noninvasive, hyperplastic epidermal reactions accompanied by loss of basal, subdermal melanocytes. Ultrastructurally, enlargement of intercellular spaces between tumor cells, increased pigment granules and membrane-bound cytoplasmic aggregates within the spaces, swollen rough endoplasmic reticula, degenerating pigment granules, and altered corneal cells were noted. Virus-like particles were observed in one tumor cell. Prelminary attempts failed to demonstrate transmissibility of the tumor, and no new cases arose under laboratory conditions. The cause of these tumors in the Japanese newt remains unknown, and it is suggested that if a viral agent is involved then other environmental cofactors (diet, temperature, or water constituents) are required for its expression.

Animals↗
PubMed1977

Velocity of head growth during the perinatal period.

Growth velocity of head circumference was studied longitudinally in different gestational age groups of 222 appropriate-weight-for-dates (AFD) and 94 small-for-dates (SFD) healthy infants during the first 5 months of life. Term AFD and SFD infants showed a steady slowing of growth rate of head circumference from birth. In contrast, preterm AFD infants of less than 36 weeks' gestation showed an increasing velocity of growth followed by slowing, with maximum velocity occurring between 30 and 40 days after birth. The shorter the postconceptional age at birth the later maximum velocity occurred. However, those preterm AFD infants of between 30 and 33 weeks' gestation who were given a high caloric feed showed a similar velocity curve to that of infants of 34-37 weeks of gestation. Cross-sectional data were used to estimate growth velocity of head circumference in the fetus. Two conclusions emerged. First, there is a slowing of head growth velocity from 31 weeks' gestation in utero, and second, term infants show a marked increase in volocity after birth. Though the occurrence of maximum velocity of head growth is delayed in the preterm infant, the net effect is such that at a given postconceptional age his head circumference is greater than that of the term infant, at least within the first 5 postnatal months.

Body Weight↗
PubMed1977

Factors which influence the timing of maximum growth rate of the head in low birthweight infants.

The postnatal rate of head growth in 63 infants of less than 34 weeks' gestation was examined retrospectively, together with that of 7 other infants of between 34 and 40 weeks' gestation who had severe respiratory illnesses. From the serial measurements of head circumference the timing of maximum velocity of postnatal head growth was examined and related to the infant's gestational age, nutrition, and respiratory illness during the neonatal period. Within this group of infants the longer the gestation the earlier maximum head growth velocity occurred. For infants of similar gestational ages the presence of a severe respiratory problem was associated with a delay in the time of maximum head growth. Differences in caloric intake during the first week of life did not seem to affect significantly the timing of maximum head growth velocity.

Cephalometry↗
PubMed1977

Timing of intraventricular haemorrhage.

The detection of the onset of intraventricular haemorrhage (IVH) during life is a necessary preliminary to understanding the cause of this condition. In 10 infants of very low birthweight treated with serial transfusions of adult blood the proportions of transfused cells circulating after each transfusion were compared with the proportion of transfused cells found in the intraventricular clot at necropsy. This allowed the timing of IVH to be restricted retrospectively to the period between consecutive blood transfusions. In addition, the proportional changes of transfused cells produced by infusion of a known red cell mass allow changes in the babies' original red cell mass to be followed during life. A fall in this value occurred in 8 infants dying with IVH and was taken to indicate haemorrhage. Comparison of the two methods in 9 infants suggested that, while in some cases intraventricular bleeding occurs rapidly, in others it takes place over a period of time. The interval between birth and the onset of haemorrhage was directly proportional to the gestational age of the infant.

Blood Transfusion↗
PubMed1977

Effect of blood transfusion in low birthweight infants.

143 fresh blood transfusions were given to 32 low birthweight babies, 28 of whom had hyaline membrane disease. The arterial or central venous pressure was raised by a blood transfusion if before transfusion the mean arterial pressure was less than 35 mmHg or if the diastolic central venous pressure was less than -- 0-5 mmHg. There was no effect of blood transfusion on pH. It therefore appears either that metabolic acidosis in hyaline membrane disease is not caused by poor peripheral perfusion or that blood transfusion does not increase peripheral blood flow in this condition. The safety of the procedure is assessed.

Blood↗
PubMed1976

Affinity chromatography of amine oxidase from Aspergillus niger.

Omega-Aminohexyl-Sepharose 4B served as an excellent biospecific adsorbent for affinity chromatography of amine oxidase (monoamine:O2 oxidoreductase (deaminating), EC 1.4.3.4) from Aspergillus niger. The enzyme was completely adsorbed on this affinity resin when applied to a column in 0.1 M potassium phosphate buffer (pH 7.2). Although a small part of the enzyme was retained on the column through ionic interaction and eluted with 1.0 M potassium phosphate buffer (pH 7.2), most of the enzyme adsorbed was eluted with 0.5 M potassium phosphate buffer (pH 7.2) containing 10 mM butylamine. Essentially no retention of the enzyme on a column of epsilon-aminopentyl-Sepharose or delta-aminobutyl-Sepharose occurred under the same conditions, indicating that an appropriate length (more than approx. 12 A) of a hydrocarbon extension between the agarose matrix and the terminal amino group would be necessary for efficient adsorption of amine oxidase. The modification of the enzyme with 3-methyl-2-benzothiazolinone hydrazone (carbonyl inhibitor) or dithionite (reducing agent) resulted in loss of the ability to bind to omega-aminohexyl-Sepharose. It was also demonstrated that the affinity chromatography on omega-aminohexyl-Sepharose can be used as a powerful means of purifying this enzyme from crude extracts of Aspergillus niger. All of the three adsorbents were effective as a substrate in the amine oxidase reaction, but their substrate activities were as low as the corresponding free diamines.

Aspergillus niger↗
PubMed1975

Comparative studies on the properties of tryptophanase and tyrosine phenol-lyase immobilized directly on Sepharose or by use of Sepharose-bound pyridoxal 5'-phosphate.

Tryptophanase from Escherichia coli B/qt 7-A and tyrosine phenol-lyase (beta-tyrosinase) from Escherichia intermedia were immobilized on Sepharose 4B by several direct coupling reactions or through pyridoxal 5'-phosphate previously bound to Sepharose. The most active preparation of immobilized tryptophanase was obtained by coupling tetrameric apoenzyme to pyridoxal-P bound on Sepharose at the 6-position through a diazo linkage. This immobilization procedure involves the formation to Schiff base linkage between 4-formyl group of Sepharose-bound pyridoxal-P and the epsilon-amino group of the lysine residue at the active center of one subunit of tetrameric apo-tryptophanase, followed by the fixation of the Schiff base linkage by reduction with NaBH4. In the case of beta-tyrosinase having two catalytic centers, however, this method was not so suitable as the case of tryptophanase. Direct coupling of the apoenzyme to CNBr-activated Sepharose or to a bromoacetyl derivative of Sepharose gave better results. In each case, the affinity for substrate or coenzyme was scarcely influenced by the immobilization. When used repeatedly in a batch system or continuously in a flow system in the absence of added pyridoxal-P, immobilized holo-tryptophanase of holo-beta-tyrosinase gradually lost its original activity; however, supplement of pyridoxal-P to the reaction system restored its initial activity. From the kinetic analyses of these phenomena, the rate constants of coenzyme dissociation from immobilized tryptophanase and beta-tyrosinase were calculated. Upon immobilization, the pH optima of both enzymes shifted 0.5 to 1.0 pH unit to the alkaline side. Both immobilized enzymes showed higher thermal stability and resistance to a denaturing agent such as guinidine-HCl than their free counterpart. Furthermore, the reactivity of sulfhydryl group of beta-tyrosinase, in connection with its coenzyme-binding property, was conveniently studied by use of the immobilized enzyme.

Apoenzymes↗