Embryonic death in mouse due to lead exposure.

Female mice which displayed a vaginal plug after mating were given a diet containing 0, 0.125, 0.250, 0.500% of lead as lead acetate and were dissected 16 to 18 days later. Lead treatment was found to reduce significantly the incidence of pregnancies and to increase the postimplantation loss in the pregnant females.     

Embryonic death in mouse due to lead exposure

Summary Female mice which displayed a vaginal plug after mating were given a diet containing 0, 0.125, 0.250, 0.500% of lead as lead acetate and were dissected 16 to 18 days later. Lead treatment was found to reduce significantly the incidence of pregnancies and to increase the postimplantation loss in the pregnant females.     

Tannic acid inhibits insulin-stimulated lipogenesis in rat adipose tissue and insulin receptor function in vitro

Tannins occur naturally in relatively abundant amounts in fruits, herbal medicines and common beverages. Thus an understanding of how these polyphenols affect peptide hormone action is of importance. We report here that tannic acid (a hydrolysable tannin) inhibits insulin-stimulated lipogenesis in rat adipose tissue in vitro, with an IC₅₀ estimated to be about 350 M. However, its monomer, gallic acid, did not show a similar inhibitory effect at concentrations up to 1 mM. The inhibition by tannic acid was less evident with higher concentrations of bovine serum albumin in the incubation buffer. This was attributed to the formation of a tannin-protein complex between bovine serum albumin and tannic acid. In a binding assay, it was observed that the specific binding of insulin to its receptor was not inhibited by tannic acid in the concentration range 0–200 M. However, insulin-stimulated autophosphorylation of the insulin receptor, and receptor-associated tyrosine kinase phosphorylation of RR-SRC peptide, were inhibited by tannic acid at concentrations as low as 25 M. Our data do not support the current speculation that tannins affect the activity of peptide hormones by binding to them. Therefore, our finding opens up a new perspective in the understanding of the mode of action of tannins on such hormones.     

Tannin und Adrenalin

Summary Tannic acid in concentrations which of themselves have no action potentiates and prolongs the action of adrenaline on the isolated rabbit intestine (inhibitory effect) and on the isolated non-pregnant rabbit uterus (excitatory effect). The adrenaline-pressor effect in the decapitated cat and, in the same species, its stimulant action on the nictitating membrane (either denervated or normal) may also be potentiated by tannic acid. Since the oxidation of adrenalinein vitro is inhibited by tannic acid, it seems that this—in addition to a possible increase of permeability—is mainly responsible for the potentiation of adrenaline.     

The effect of a low protein diet on the adipocytes of rat perigenital fat

Weanling rats were fed a low protein diet for 6 weeks and their weights were 50% less than controls. There were significantly fewer adipocytes per microgram adipose tissue, but estimates of the number of adipocytes per rat indicated that the diet had much less effect on adipocyte number than on b. wt.     

Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells

A homogeneous glycoprotein (mol. wt 40,000) containing 34% carbohydrate was isolated from Aloe arborescens var. natalensis. At a concentration of 5 micrograms/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed.     

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. There was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).     

Increased ALA dehydratase activity and spleen weight in lead-intoxicated rats. A consequence of increased blood cell destruction

Lead was given in the diet (1%) to rats from birth and at different times the animals were studies for delta amino levulinic acid dehydratase (ALAD) activity, spleen weight, 59Fe incorporation in erythrocytes and 51Cr-labeled erythrocytes survival. The increased ALAD and spleen weight found after lead treatment is explained as a consequence of a shortened survival, which results in a younger age of circulating erythrocytes with higher ALAD activity.     

Lactate dehydrogenase and glutamate dehydrogenase activities in the circumventricular organs of rat brain following neonatal monosodium glutamate

Glutamate (glu) an excitatory neurotransmitter amino acid, is present in high concentrations in the mammalian central nervous system and is the most abundant amino acid in our daily diet. In the present study the activities of lactate dehydrogenase (LDH) and glutamate dehydrogenase (GDH) were evaluated in the circumventricular organs (CVO) of the brain in 25-day-old rats following MSG administration at a dose of 4 mg/g b.wt during the first ten days of life. The results show the LDH activity increased to 265% of that in the control (p<0.001), whereas GDH activity was significantly decreased (p<0.05), The great elevation in LDH, a cytoplasmic marker enzyme, is apparently due to cytoskeletal changes brought about as a consequence of glu toxicity, whereas lowered GDH activity indicates altered glu homostasis in the blood-brain-barrier deficient areas following neonatal exposure to glu.     

Enzymatic activities in the liver, and muscle nucleic acids, in swine receiving an unbalanced diet with an excess of methionine for 100 days

Twelve growing Swine were fed an 18% protein diet (Maize and Soja bean) for one hundred days containing either 0,6% sulfur amino acids (basal diet) or 0,6% and 1% DL-methionine added to the control diet. Such an excess, reduced food intake and body weight gain mainly during the "finishing period" (60 to 100 kg). The RNA/DNA and protein/DNA ratios in the muscle did not show any difference. Hepatic activities of some enzymes involved in glycolysis, gluconeogenesis and amino acid metabolism, were unchanged, except that of methionine adenosyl transferase, the first step of transsulfuration, which was induced in proportion with the amount of the methionine ingested. Swine seemed to adapt to the excessive methionine intake, which did not show any toxicity in our experimental conditions.     

Possibility of using131I-albumin as a marker for the estimations of microbial protein synthesis rates in the rumen

Summary Total microbial protein synthesis rates in the rumen of buffaloes were estimated by isotope dilution technique, using¹³¹I-albumin treated with tannic acid as a marker. The animals were fed groundnut cake treated with formaldehyde to meet 50% of their digestible crude protein (DCP) requirement and 2.5% urea molasses mixture was given to meet the remaining requirement of DCP. Wheat straw was fed as the basal roughage. The total average microbial protein synthesis was 58.14 g/day.     

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Summary Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. These was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).Acknowledgments. This work was supported, in part, by a grant (HL-03299) and a Research Career Award (HL-00734) from the National Institutes of Health, and by funds from Mary L. Smith and the Commonwealth of Pennsylvania.     

The effect of a low protein diet on the adipocytes of rat perigenital fat

Summary Weanling rats were fed a low protein diet for 6 weeks and their weights were 50% less than controls. There were significantly fewer adipocytes per g adipose tissue, but estimates of the number of adipocytes per rat indicated that the diet had much less effect on adipocyte number than on b.wt.     

Latent iron deficiency alters gamma-aminobutyric acid and glutamate metabolism in rat brain

A diet containing 18-20 mg iron/kg to young weaned rats for 8 weeks altered the metabolism of gamma-aminobutyric acid and glutamate in the central nervous system without affecting blood hemoglobin. Subsequent rehabilitation with 390 mg iron/kg diet for 2 weeks normalized these changes.     

Effect of tannic acid on the Ehrlich ascites tumor cells.

Tannic acid was used to fix and stain Ehrlich ascites tumor cells in suspension. An increase in surface microvilli and cytoplasmic blebs in the tumor cells was observed. The mechanism of tannic acid induced surface morphological changes in tumor cells and the formation of a precipitate of protein-tannic acid-heavy metal complex are discussed.     

Latent iron deficiency alters gamma-aminobutyric acid and glutamate metabolism in rat brain

Summary A diet containing 18–20 mg iron/kg to young weaned rats for 8 weeks altered the metabolism of gamma-aminobutyric acid and glutamate in the central nervous system without affecting blood hemoglobin. Subsequent rehabilitation with 390 mg iron/kg diet for 2 weeks normalized these changes.     

Quelques propriétés basiques de la streptomycine

Summary Streptomycin forms an insoluble complex with organic substances of which the isoelectric point is situated in the acid range such as cephalin, oleic, palmitic, and tannic acid.     

A method for distinction between RNA and DNA in aldehyde and osmiumtetroxide-fixed electron microscopic autoradiographs.

A simple method for distinction between RNA- and DNA-containing structures in aldehyde- and osmiumtextroxide-fixed electron microscopic autoradiographs (or ordinary thin sections) is described: the developer and the acetic acid used for processing autoradiographs extract selectively uranium acetate from DNA containing-structures which, after staining with lead citrate, leads to a characteristically 'bleached' appearance of the DNA.     

Adaptation of lipase and phospholipase A activities in pancreas and pancreatic juice in rats with diets rich in triglycerides and phospholipids]

Lipid rich diets containing about 20% of triglycerides or phospholipids given to Rats during 2 months were observed to increase lipase and phospholipase A2 activities in pancrease and pancreatic juice. The phospholipase and lipase activities are higher, respectively, on the phospholipid and triglyceride diet. Lower effects are observed after a 7-day administration of diet containing 40% of total lipid.     

Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells

Summary A homogeneous glycoprotein (mol.wt 40,000) containing 34% carbohydrate was isolated fromAloe arborescens var.natalensis. At a concentration of 5 g/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed.