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Biomedical subjects

H Hoshi

Publications and source records attributed to H Hoshi.

At least 307 records · Page 17Linked to original sources
PubMed1987

Biodistribution of N-isopropyl-p-iodoamphetamine in the rat brain.

The biodistribution of N-isopropyl-p-iodoamphetamine (IMP) was studied in the rat brain. 131I-labelled IMP was injected intravenously in awake animals. Activities in the brain of Sprague-Dawley rats were 2.68-3.22 (% dose/g) in the cortex and 0.59-0.66 (% dose/g) in the white matter at 1 min p.i. Activities in the cortex were slightly increased at 60 min p.i., while activities in the white matter increased markedly at 60 min and 6 h p.i. Therefore, the cerebral cortex-to-white matter ratio decreased from 5 to 1 within 60 min after injection. Autoradiograms of the rat brain at 1-10 min p.i. showed high contrasts. Activities were high in the cortex and low in the white matter, but homogeneous at 60 min-6 h. IMP seems to be a useful agent for cerebral perfusion imaging in the early phase after injection. Knowledge of biodistribution of this agent is considered to be indispensable for the interpretation of images.

Amphetamines↗
PubMed1987

Optimal positioning for CT examinations of the skull base. Experimental and clinical studies.

To evaluate the most appropriate CT angles for the skull base, four adult phantom skulls of various shapes were examined by CT. 15 osseous sites in each skull base were selected and the optimum angle for their delineation was determined. Using Reid's base line (0 degree), many sites could be imaged best at angles up to +20 degrees, and +10 degrees was found to be optimum. Examinations of patients using OM-line as a reference disclosed imaging rates in excess of 70% for sites other than the hypoglossal canal, the optic canal and foramen rotundum, which are in horizontal planes.

Adolescent↗
PubMed1986

Two apparent human endothelial cell growth factors from human hepatoma cells are tumor-associated proteinase inhibitors.

Two polypeptides from secretory products of human hepatoma cells were isolated and characterized on the basis of their stimulation of maintenance and growth of human endothelial cells in serum-free cell culture. Both factors were purified to homogeneity by a combination of reverse-phase, ion exchange, and molecular filtration high performance liquid chromatography. One factor (endothelial cell growth factor (ECGF-2a) had Mr approximately 6,500 and pI near 6. The second (ECGF-2b) had Mr = 27,000 and a pI below 4.0. Both ECGF-2a and ECGF-2b exhibited single NH2-terminal sequences. The first 25 NH2-terminal residues of ECGF-2a and the first 49 residues of ECGF-2b were determined by gas-phase microsequencing. All clearly determined residues of ECGF-2a were identical with human pancreatic secretory trypsin inhibitor. All assignable residues of ECGF-2b were identical with urinary glycoprotein proteinase inhibitor (HI-30/EDC1). Both proteins are absent or at low levels in normal plasma and urine, but appear during acute inflammatory disease and cancer. Amino acid composition of ECGF-2a and ECGF-2b was also similar to human pancreatic secretory inhibitor and HI-30/EDC1, respectively. Both ECGF-2a and ECGF-2b inhibited bovine pancreatic trypsin (2 micrograms/ml) by 50% at 750 ng/ml. ECGF-2a and ECGF-2b stimulated endothelial cell number at a half-maximal dose of 50 ng/ml (8 nM) and 80 to 130 ng/ml (5 to 9 nM) protein, respectively. When assayed under identical conditions, no effect of either factor on human smooth muscle cells, human hepatoma cells, or human, rat, and mouse fibroblasts could be detected.

Amino Acid Sequence↗
PubMed1986

Role of lipoproteins in growth of human adult arterial endothelial and smooth muscle cells in low lipoprotein-deficient serum.

Recently improved culture conditions for human adult arterial endothelial and smooth muscle cells from a wide variety of donors have been used to study the effects of lipoproteins on proliferation of both cell types in low serum culture medium. Optimal growth of endothelial and smooth muscle cells in an optimal nutrient medium (MCDB 107) containing epidermal growth factor, a partially purified fraction from bovine brain, and 1% (v/v) lipoprotein-deficient serum was dependent on either high- or low-density lipoprotein. High- and low-density lipoprotein stimulated cell growth by three- and five-fold, respectively, over a 6-day period. Optimal stimulation of both endothelial and smooth muscle cell growth occurred between 20 and 60 micrograms/ml of high- and low-density lipoproteins, respectively. No correlation between the activation of 3-hydroxyl-3-methylglutaryl coenzyme. A reductase activity and lipoprotein-stimulated cell proliferation was observed. Lipid-free total apolipoproteins or apolipoprotein C peptides from high-density lipoprotein were partially effective and together with oleic acid effectively replaced native high-density lipoprotein for the support of endothelial cell growth. In contrast, apolipoproteins or apolipoprotein C peptides from high-density lipoprotein alone or with oleic acid had no effect on smooth muscle cell proliferation. The results suggest a functional role of high- and low-density lipoproteins and apolipoproteins in the proliferation of human adult endothelial and smooth muscle cells.

Apolipoproteins↗
PubMed1986

Isolation, growth requirements, cloning, prostacyclin production and life-span of human adult endothelial cells in low serum culture medium.

Endothelial cells from autopsy and biopsy specimens from a variety of adult human vascular tissue were harvested by collagenase treatment and gentle swabbing of the lumenal surface. Nutrient medium MCDB 107 containing a partially purified brain-derived growth factor (5 micrograms/ml), epidermal growth factor (10 ng/ml) and only 2% (v/v) fetal bovine serum supported clonal and long-term serial culture (17.6 to 26.1 cumulative population doublings) of endothelial cells from vena cava, thoracic aorta and tibial arteries at a 70% rate of success. Cumulative doublings of the cell population from eight cultures were inversely proportional to age of donor of the vascular tissue from which cells were isolated. Heparin had an enhancing effect on cell growth that varied with cell strain. Prostacyclin production of human adult endothelial cell cultures was stimulated by arachidonate and thrombin by 17 to 20 and 2 to 3-fold respectively. Endogenous and stimulated rates of prostacyclin production by human adult endothelial cells were 2 to 3 times that of human adult smooth muscle cells and 20 to 30 times that of human fibroblasts.

Adult↗
PubMed1986

Formation of lymph follicles in draining lymph nodes after local injection of various antigenic substances in mice.

Formation of lymph follicles in draining popliteal lymph nodes was examined in 8-week-old, male C57Bl/6 mice which had been injected in the rear footpad with any one of eleven test substances including thymus-dependent and thymus-independent antigens, and killed after 6-14 days. HGG (10-100 micrograms), MGG, tetanus and diphtheria toxoids (2-10 Lf) and influenza HA vaccine (35 CCA) induced germinal centers in association with existing follicles, but failed to produce new follicles in draining nodes. KLH (10-100 micrograms), SRBC (1 X 10(8)) and formalin-killed pertussis organisms (5 X 10(8)) induced germinal centers in existing follicles and also produced new follicles which soon developed germinal centers. Levan and PVP (10-100 micrograms) induced neither germinal centers nor new follicles. Ferritin (100 micrograms) virtually failed to induce germinal centers but produced a significant number of new primary follicles. In further experiments, artificially aggregated substances were examined with regards to their ability of inducing lymph follicle formation in draining nodes. Precipitated proteins such as alum-precipitated PHA, HGG, tetanus and diphtheria toxoids, "Sepharose"-PHA and "Sepharose"-HGG induced a significant number of new follicles. These observations suggest that efficient follicle formation is associated with particulate and high-molecular-weight antigens which are liable to be phagocytized, whereas soluble, poorly phagocytized antigens tend to be inefficient. Soluble proteins may be effective if given in precipitated form. Thymic dependency appears to be irrelevant. The present results point to a possible participation of macrophages in the mechanism of follicle formation.

Animals↗
PubMed1986

Diagnosis of diffuse hepatocellular diseases using SPECT.

In the scintigraphic diagnosis of diffuse hepatocellular diseases, increased splenic uptake of colloids and splenomegaly are helpful signs. To quantify these patterns, the volume and activity of liver and spleen were measured by using single photon emission computed tomography (SPECT). The spleen-to-liver (S/L) ratios in volume and activity that were calculated from SPECT images were estimated in normal individuals and in patients with diffuse hepatocellular diseases. The maximum normal limits of S/L ratios of volume, activity, and activity/volume were predicted as 0.19, 0.087, and 0.72 (mean +/- 2 s.d.). Twenty-two of twenty-three patients (96%) with liver cirrhosis had at least two elevated S/L ratios, and three elevated S/L ratios could clearly differentiate the patient with liver cirrhosis from normal individuals. On the other hand, only six patients (32%) with chronic hepatitis had elevation of any S/L ratio. Abnormal S/L ratios of activity/volume in the range from 0.72 to 1.05 were not obvious on planar or SPECT images.

Chronic Disease↗