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Biomedical subjects

I Shimizu

Publications and source records attributed to I Shimizu.

At least 145 records · Page 8Linked to original sources
PubMed1984

Development of retinohypothalamic projections in the chick embryo.

The retinal projection to the hypothalamus was investigated in embryonic as well as hatched chick using wheat germ agglutinin-conjugated horseradish peroxidase as an anterograde tracer. The presence of an aggregation of anterogradely labeled terminals in the hypothalamus was used to identify the suprachiasmatic nucleus (SCN). The first clear labeling of retinal fibers in the SCN was found on embryonic day 16, whereas labeling was found in the other primary visual projections, in the diencephalon and mesencephalon, several days earlier. Thus, the retinohypothalamic projection is the last primary visual pathway to develop in the chick embryo.

Animals↗
PubMed1984

Postprandial release of neurotensin-like immunoreactivity and its mechanism.

The effects of various ingested materials on plasma neurotensin-like immunoreactivity (NTLI) in humans were investigated using a newly developed, specific radioimmunoassay. Plasma NTLI was determined after its extraction with acid/acetone (recovery 77 +/- 4%). The intraassay and interassay coefficients of variation were 3.6% and 8.9%, respectively. The plasma concentration of human NTLI in normal subjects was 5.6 +/- 2.9 pmol/l and showed no significant sex difference. Ingestion of a test meal (150 g of Campbell's condensed meat soup) caused a biphasic rise in plasma NTLI from a basal level of 5.7 +/- 1.0 pmol/l to 10.8 +/- 1.2 pmol/l after 30 min and 9.6 +/- 1.1 pmol/l after 120 min. Ingestion of 5.5 g fat resulted in a biphasic rise in plasma NTLI from a basal level of 4.8 +/- 0.3 pmol/l to 8.9 +/- 0.3 pmol/l after 15 min and 11.9 +/- 0.4 pmol/l after 90 min. When 100-150 mg of ileal mucosa was perfused with a solution of 2 mEq/l fatty acids, 1 mM or 5 mM sodium taurocholate or 154 mM sodium bicarbonate (NaHCO3), the release of NTLI from the mucosa into the perfusate was 2.3-fold, 4.3-fold and 7.5-fold, respectively, over the base level. These results indicate that NTLI release is stimulated by ingestions of meat soup and fat and that NTLI present in the human ileum is released by the direct actions of solutions of fatty acid, sodium taurocholate, and NaHCO3 on the ileal mucosa. These findings strongly suggest that neurotensin (NT) has a physiological role in gut physiology.

Adult↗
PubMed1983

Experimental retinal autoimmunity (ERA) in strain 13 guinea pigs: induction of ERA-retinopathy with rhodopsin.

Strain 13 guinea pigs injected with either homologous or bovine rhodopsin, the visual pigment of the retinal outer segments, in complete Freund's adjuvant (CFA) developed experimental retinal autoimmunity (ERA). Initial clinical signs of disease were seen within 21 days after immunization. Pathologic examination of the eyes revealed the presence of inflammatory cells in the choroid and the destruction of the retinal rod outer segments. The unique feature of this disease is that despite the destruction of the inner and outer segments of the retina, at no time is there a substantial inflammatory cell infiltrate. Even as late as 45 days after immunization, when destruction of the retinal ganglion cell layer was noted, no inflammatory cells were detected in the retina. These findings suggest that the retinal inner and outer segments are the target of the autoimmune reaction subsequent to sensitization with purified rhodopsin-CFA.

Animals↗
PubMed1975

Effect of temperature on ergosterol biosynthesis in yeast.

Anaerobically grown Saccharomyces cerevisiae was aerated for 7 hr at 20 degrees, 30 degrees, or 40 degrees, in a phosphate buffer containing 2% glucose. At elevated temperature (40 degrees), de novo synthesis of squalene and sterois in the aerated yeast was only 32-35% of that at lower temperature (20 degrees or 30 degrees), and this decrease was attributed to the repression of the enzymes involved in the synthesis of mevalonate from acetyl-COA. In addition, at elevated temperature, the metabolic flux from squalene to ergosterol was blocked at squalene epoxidation, lanosterol demethylation, and ergosta-5, 7, 22, 24(28)-tetraene-3beta-ol reduction.

Acetyl Coenzyme A↗