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Biomedical subjects

M Aoki

Publications and source records attributed to M Aoki.

At least 757 records · Page 42Linked to original sources
PubMed1984

Cellular and subcellular distribution of iron in the lamina propria of rat duodenum.

Cellular and subcellular distribution of iron in the lamina propria of rat duodenum was studied after a single i.p. injection of iron dextran, using electron microscopy and peroxidase cytochemistry. X-ray spectrum microanalysis was used for positive identification of iron. Iron-containing particles (IP) were found in the cytoplasm of three cell types, viz. macrophages, pericytic reticular cells and sheathing fibrocytes. IP-containing organelles in lamina propria cells were more heterogeneous compared to absorptive cells and, in addition, some differences were noted in the subcellular distribution of IP in the 3 cell types. A common denominator in these 3 cell types was the presence of endogenous peroxidase, also shared by Kupffer cells which are known to be involved in iron storage. Peroxidase activity was absent in absorptive epithelial cells. It is hypothesized that the cells of the lamina propria, like Kupffer cells, may be the site of storage of excess iron absorbed, releasing iron upon demand and migrating into the lumen to prevent iron overload. In this fashion they may regulate the exchange of iron with the environment. The presence of peroxidase in these as well as Kupffer cells, and its absence in absorptive cells also raises the possibility that this enzyme may be related to certain aspects of iron storing process.

Animals↗
PubMed1984

Acromegaly with multiple secreting pituitary adenomas.

A case of acromegaly with two separate growth hormone-secreting pituitary adenomas is presented. The multiplicity was suspected on computerized tomographic scan and confirmed at transsphenoidal surgery. Possible occurrence of multiple adenomas is discussed.

Acromegaly↗
PubMed1984

Primary ovarian pregnancy in a cystic teratoma.

Hemoperitoneum was identified by culdocentesis in a 26-year-old woman suffering acute abdominal pain. A pregnancy test was positive. Operation indicated a ruptured ovarian pregnancy, and histologic examination revealed primary intrafollicular ovarian pregnancy in a cystic teratoma. Ovarian pregnancy in an ovarian tumor is exceedingly rare.

Adult↗
PubMed1984

Time variation of radon daughters concentration in snowfall.

Time variation of radon daughters concentration in snowfall was measured continuously. The relations of radon daughters concentration in snowfall to the precipitation and to atmospheric radon daughters concentration were investigated. It has become clear that when precipitation is small, radon daughters concentration in snowfall is distributed in a wide range, and that the quantity of radon daughters brought to ground surface by snowfall is proportional to precipitation. Washout effect of the snowfall on atmospheric radon daughters was also investigated.

Atmosphere↗
PubMed1983

A new reagent for the rapid determination of total hemoglobin as hemiglobincyanide in blood containing carboxyhemoglobin.

Kinetics of conversion of HbCO to HiCN with various K3Fe(CN)6-KCN reagents was examined photometrically. Complete conversion of HbCO to HiCN required about 8 hr, 150 min, and 50 min with Drabkin's reagent, that of van Kampen and Zijlstra, and that of Taylor and Miller, respectively. The absorbance at 540 nm was stabilized practically in 5 min even in CO-saturated blood when a reagent containing a 1600-fold excess of K3Fe(CN)6 to Hb iron was used. A slight increase in the absorbance was observed around 504 nm in the HiCN solution produced with the reagent. The absorbance at 540 nm in the solution, however, was stable until at least 120 min after mixing. From these findings, a reagent containing a 1600-fold excess of K3Fe(CN)6 to Hb iron and an incubation time of 5 min were used for the complete conversion of HbCO to HiCN. The stabilization of the absorbance at 540 nm was often prolonged to 10 min when the reagent was stored over 2 weeks. The reagent was compared with two other reagents, using 20 blood samples containing various amounts of HbCO, and proved to be suitable for the determination of total Hb in blood containing elevated HbCO as well as in ordinary blood.

Carboxyhemoglobin↗
PubMed1983

Rat pituitary adenoma and hyperplasia induced by caffeine administration.

The effect of caffeine by oral administration on female Wistar rats was studied for 12 months. High concentrations (2000 micrograms/mL) of caffeine caused a decrease in body weight and an increase in the weight of the pituitary gland in these rats. Increased pituitary weight was caused by the growth of a pituitary adenoma or hyperplasia. Pituitary adenomas and instances of hyperplasia were found in 27 of the 40 rats in the caffeine group, compared to 9 of the 30 rats in the control group. The histologic classification used was microadenoma, papillary (or sinusoidal) macroadenoma, and diffuse macroadenomas. These adenomas appeared to be endocrinologically nonfunctioning.

Adenoma↗