Direct effects of heparin on basal and stimulated aldosterone production in rat adrenal glomerulosa cells

Direct effects of heparin (0.1-10 IU/ml) on basal and stimulated aldosterone production have been studied using intact rat adrenal glomerulosa cells. Heparin at any dose did not affect basal aldosterone production when added to the incubation medium. Heparin at a 0.01 IU/ml dose had no effect on aldosterone production maximally stimulated by angiotensin II (AII, 4.8 X 10(-8) M), ACTH (4.3 X 10(-9) M) or potassium (8.0 mM). However, heparin at 0.1 and 0.3 IU/ml doses selectively blocked aldosterone production maximally stimulated by AII but not by ACTH or potassium, while the compound at 1 and 10 IU/ml doses inhibited aldosterone production maximally stimulated by these three stimuli. In addition, the inhibitory effect of 0.3 IU/ml heparin occurred as early as 30 min after incubation with heparin. These data suggest that heparin at 0.1 and 0.3 IU/ml doses acts directly on adrenal zona glomerulosa to selectively block the stimulatory action of AII, while the compound at 1 and 10 IU/ml doses inhibits all the stimulatory actions of AII, ACTH and potassium.     

Generation of phenoxy radicals by methemoglobin-hydrogen peroxide studied by electron paramagnetic resonance

The free radical intermediates of phenol derivatives, produced by the methemoglobin-hydrogen peroxide system at pH 5 and 7, are detected by electron paramagnetic resonance equipped with a continuous-flow apparatus. All the radicals from phenols are the phenoxy radicals, as identified by analyzing the observed hyperfine structures of the spectra with the aid of SCF-LCAO MO calculations. Comparing with the reaction of Fenton's reagent, it is concluded that free OH radical, even if it exists, is not liberated into the solution in the methemoglobin-hydrogen peroxide system.     

Cholesterol metabolism in ExHC (exogenous hypercholesterolemic) rats.

Exogenous hypercholesterolemic (ExHC) rats, that develop hypercholesterolemia for exogenous cholesterol, are an established strain Isolated from Sprague-Dawley (SD) rats by Imai and Matsumura ((1973) Atherosclerosis, 18, 59-64). The present study was carried out to clarify the cause of hyperresponsivity in ExHC rats to dietary cholesterol. As early as one day after feeding a high cholesterol diet (1%) serum cholesterol level was doubled in ExHC rats, while the level of hepatic cholesterol was two-thirds of SD rats. The elevation of serum cholesterol was mainly attributed to the d less than 1.006 g/ml fractions. Cholesterol feeding increased fecal bile acid excretion in both strains, but to a more greater extent in SD rats. Absorption of dietary cholesterol and synthesis of cholesterol in vivo were similar between the strains. The uptake of beta-very-low-density-lipoproteins (beta-VLDL) in vivo and the primary cultured hepatocytes was lower in ExHC rats, when a high-cholesterol diet was fed. Even without feeding of a high-cholesterol diet, preincubation with cholesterol-rich lipoproteins caused a lower association and degradation of beta-VLDL by the hepatocytes from ExHC rats. Incubation of hepatocytes with cholesterol-rich lipoproteins did not affect the secretion of [14C]cholesterol into the density less than 1.006 g/ml fraction, but suppressed the secretion into the medium density greater than 1.006 g/ml fractions. These results suggest that ExHC rats, as compared to SD rats, are defective of hepatic uptake and processing cholesterol to bile acids.     

Formation of anti-plant viral protein by Mirabilis jalapa L. cells in suspension culture

The extract of Mirabilis jalapa cultured cells and its precipitate fraction with 90% saturated ammonium sulfate showed an anti-plant viral activity comparable to that of the roots and leaves of the original plant. In the immunodiffusion experiment, the extract of cultured cells positively reacted with MAP (Mirabilis Anti-plant viral Protein) anti-serum. The changes in MAP formation during cell growth and the MAP content of roots and leaves were examined using enzyme-linked immunosorbent assay (ELISA). MAP formation proceeded almost in parallel with cell growth. The MAP content of cultured cells reached the highest level (0.6 mg/g dry weight) on the 9th day after inoculation, which was less than one-third of the content of the roots but three times larger than that of the leaves.Abbreviations MAP Mirabilis anti-plant viral protein - TMV tobacco mosaic virus - 2,4-D 2,4-dichlorophenoxyacetic acid - ELISA enzyme-linked immunosorbent assay Studies on the production of anti-plant viral substances of higher plant cells in suspension culture. Part 1     

Activity of platelet-activating factor (PAF) acetylhydrolase in plasma from patients with ischemic cerebrovascular disease

Platelet-activating factor (PAF) is metabolized by a specific enzyme, PAF acetylhydrolase, which may play an important role in the manifestation of the biological activities of PAF in vivo. The activity of PAF acetylhydrolase in plasma of patients with ischemic stroke was higher than that in healthy controls. The incidence of irreversible platelet aggregation in response to PAF, as well as to ADP, was found to be higher in patients than in controls. The patients whose platelets responded with irreversible aggregation to PAF displayed a higher activity of plasma PAF acetylhydrolase than those with only reversible aggregation. In controls, PAF acetylhydrolase activity correlated positively, although weakly, with LDL-cholesterol, which may reflect the major role of LDL in carrying this enzyme. However, since there was no significant difference in plasma levels of lipids and apoproteins between patients and controls (except for apo B) and there was no significant relationship between the enzyme activity and the levels of other lipids and apoproteins, it is unlikely that increased plasma level of PAF acetylhydrolase activity in stroke patients is accounted for by an abnormality of lipoprotein metabolism. Platelet hyperfunction may be associated with augmented generation of PAF, which, in turn, may bring about the induction of the inactivating enzyme, PAF acetylhydrolase.     

Recovery of Cognitive Dysfunction via Orally Administered Redox-Polymer Nanotherapeutics in SAMP8 Mice

Excessively generated reactive oxygen species are associated with age-related neurodegenerative diseases. We investigated whether scavenging of reactive oxygen species in the brain by orally administered redox nanoparticles, prepared by self-assembly of redox polymers possessing antioxidant nitroxide radicals, facilitates the recovery of cognition in 17-week-old senescence-accelerated prone (SAMP8) mice. The redox polymer was delivered to the brain after oral administration of redox nanoparticles via a disintegration of the nanoparticles in the stomach and absorption of the redox polymer at small intestine to the blood. After treatment for one month, levels of oxidative stress in the brain of SAMP8 mice were remarkably reduced by treatment with redox nanoparticles, compared to that observed with low-molecular-weight nitroxide radicals, resulting in the amelioration of cognitive impairment with increased numbers of surviving neurons. Additionally, treatment by redox nanoparticles did not show any detectable toxicity. These findings indicate the potential of redox polymer nanotherapeutics for treatment of the neurodegenerative diseases.     

An electron microscopic study on the interstitial cells of the gizzard in the love-bird (Uroloncha domestica)

Summary A type of cells morphologically resembling fibroblasts or Schwann cells and identical with the interstitial cells as firstly described byCajal was studied electronmicroscopically.Examinations of serial sections reveal that cell membranes of these cells make close appositions (nexus) to those of all surrounding smooth muscle cells. The surfaces of these cells are also provided with nerve endings of certain axons derived from plexus myentericus.On the basis of these findings, the possible nature and function of interstitial cells are discussed.This work was supported in part by NIH Grant NB-06052.