Biomedical subjects

N Asanuma

Publications and source records attributed to N Asanuma.

21 records · Page 2Linked to original sources

PubMed1990

Identification of 5'-adenylylimidodiphosphate-hydrolyzing enzyme activity in rabbit taste bud cells using X-ray microanalysis.

X-ray microanalysis has been used to characterize the enzyme activity hydrolyzing the ATP analogue 5'-adenylylimidodiphosphate (AMP-PNP) in taste bud cells. Rabbit foliate papillae fixed with paraformaldehyde and glutaraldehyde were incubated cytochemically with AMP-PNP as the substrate and lead ion as capture agent. The reaction product which appeared on the microvilli of taste bud cells was examined using an energy dispersive X-ray microanalyzer connected to an analytical electron microscope. The X-ray spectrum thus obtained was compared with that obtained from the product obtained from the demonstration of ATPase activity. Comparison of the phosphorus/lead ratios in the two products showed that twice as much phosphorus was released from an AMP-PNP molecule by the activity in question compared with that released from an ATP molecule by ATPase activity. This indicates that the enzyme hydrolyzes AMP-PNP into AMP and imidodiphosphate and that the enzyme is adenylate cyclase or ATP pyrophosphohydrolase, which possesses a similar hydrolytic property, but not ATPase or alkaline phosphatase, which hydrolyzes AMP-PNP into ADP-NH2 and orthophosphate. This paper provides an example of the use of X-ray microanalysis as a tool for enzyme distinction. The method is applicable to a variety of enzymes and tissues.

Adenosine Triphosphate↗

PubMed1988

[Plasma concentration of estrogens and androgens in postmenopausal women with or without endometrial cancer].

Plasma estrone (E1), 17 beta-estradiol (E2), delta 4-androstenedione (delta 4-A) and testosterone (T) levels in the peripheral vein were measured in 28 postmenopausal women with endometrial cancer and 19 control subjects without cancer matched to the cancer patients for age and weight. In the cancer patients, the mean +/- SD plasma E1, E2, delta 4-A and T levels were 53.0 +/- 29.0pg/ml, 31.3 +/- 28.9pg/ml, 1.92 +/- 0.96ng/ml and 0.71 +/- 0.24ng/ml, respectively. In the controls, the mean +/- SD plasma E1, E2, delta 4-A and T levels were 51.2 +/- 27.5pg/ml, 22.4 +/- 10.1 pg/ml, 1.70 +/- 0.6ng/ml and 0.84 +/- 0.24ng/ml, respectively. Similar concentrations were found in the control subjects. The correlation of each steroids with the percentage of ideal weight was examined. The percentage of ideal weight showed no correlation with E1, E2, delta 4-A and T in either group. Insulin response during glucose administration in the cancer patients was examined, and showed no correlation with each steroids. It was concluded that there is no differences between E1, E2, delta 4-A and T levels in cancer patients and control subjects matched to the cancer patients for age and weight. No correlation of insulin with ovarian steroid production was seen in the cancer patients.

Aged↗

PubMed1983

Calcium binding sites of hamster parasympathetic neurons.

Sites of Ca localization in hamster submandibular ganglion cells have been studied by electron microscopy using the technique of Oschman et al. [11]. Electron-dense deposits, which we assume to contain Ca, are found: (i) on axonal plasma membranes; (ii) on the plasma membranes of neuron soma and its processes; (iii) on the membrane of clear vesicles in the nerve terminal; and (iv) in the matrix of mitochondria. Intracellularly injected Ca accumulates in the mitochondria. Caffeine reduces the electron-dense deposits seen in mitochondria. Caffeine induces a swelling of Golgi apparatus when applied with CaCl2, but this swelling is not observed without CaCl2. These results are discussed in the light of Ca-activated K-conductance increases, which induce 4 types of membrane potential changes [18, 19].

Animals↗