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 feeding cereal-legume diets to rats on in vitro absorption of45Ca

Summary The in vitro absorption of calcium from the duodenum was significantly less in a group of rats fed on a wheat diet than in a group fed a wheat and Bengal gram (7030) diet.     

Synaptic vesicles and other organelles of human mossy fibre endings. A morphometric study

Summary The mossy fibre ending organelles of 6 men were studied, using morphometric methods. The numerical densities of agranular, coated and dense core vesicles, as well as the number of agranular vesicles per m² of the synaptic surface and per synapse were calculated.This work was granted by INIC: Centro de Morfologia Experimental (MbP1) e Centro de Anatomia Patológica e Oncologia (MbP3).     

In vitro modulation of rat adipocyte ghost membrane fluidity by cholesterol oxysterols

The effects of cholesterol and cholesterol-derived oxysterols (cholestanone, cholestenone, coprostanone and epicoprostanol) on adipocyte ghost membrane fluidity were studied using a fluorescence depolarization method. The fluorescence anisotropy of the treated membranes was determined using 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). Cholestanone and cholesterol decreased membranes fluidity at both the concentrations tested (10 & 50 M) while the rest of the sterols did not exert any significant effect on membrane fluidity. In the presence of epinephrine, cholestanone partitioned more towards the lipid core but cholesterol partitioning was not affected. The fusion activation energies (E) obtained for membranes preincubated with cholestanone (8.6 kcal/mol) and cholesterol (8.2 kcal/mol) were not significantly different from that of untreated membranes (8.3 kcal/mol). Membranes preincubated with cholestanone and cholesterol did not exhibit any change in lipid phase throughout the temperature range (10–45°C) tested. The sterols were found to inhibit fisetin-induced phospholipid methylation in isolated rat adipocytes in the rank order of cholesterol > epicoprostanol > cholestanone=cholestenone=coprostanone, while basal methylations was unaffected. When adipocytes were preincubated with the sterols before the addition of fisetin, cholestanone and cholestenone showed 74% and 66% inhibition of maximal methylation respectively. These results indicated that cholesterol oxysterols interact differently with rat adipocyte membranes, with cholestanone interacting more with phospholipids located at the inner lipid bilayer (e.g. phosphatidylethanolamine) while cholesterol interacts more with phosphatidylcholine located at the outer lipid bilayer. This differential interaction may cause selective changes in membrane fluidity at different depths of the bilayer and thus may modulate the activities of membrane-bound proteins such as enzymes and receptors.     

Decreased incidence of renal cell carcinoma in rats with one kidney ingesting N-4-(4′-fluorobiphenyl) acetamide

Summary Buffalo strain male rats, 12 weeks of age, ingesting 0.04% N-4-(4-fluorobiphenyl)acetamide in a semisynthetic diet with both kidneys intact were more susceptible to the development of hyperplasia and carcinomas of the kidney than were rats with a uninephrectomy.     

A farnesyl arabinoside as an enhancer of glucose transport in rat adipocytes from a soft coral,Sinularia sp.

Separation of a lipophilic extract of a soft coral,Sinularia sp., assayed by enhancement of glucose transport in rat adipocytes, gave farnesyl 4-O--D-arabinopyranosyl--D-arabinopyranoside-2,2,3-triacetate (1a) whose structure was determined by spectroscopy. Enhancers of glucose transport may be useful for the prevention and treatment of diabetic disorders.     

Genetic and pharmacological models of cholinergic supersensitivity and affective disorders

Summary Increased muscarinic sensitivity has been associated with altered hormonal states (hypothyroidism and hyperadrenocorticism), chronic administration of muscarinic antagonists or antidepressants with muscarinic actions, selective breeding for anticholinesterase sensitivity, and certain inbred strains of rats and mice. Thus, both genetic and environmental factors may influence muscarinic receptor sensitivity. The reasonably detailed studies on the selectively-bred rats have revealed that the Flinders Sensitive Line (FSL) rats weigh less, are less active, are more sensitive to muscarinic agonists and to stressors, and have higher concentrations of hippocampal and striatal muscarinic receptors than normal, or the selectively-bred, Flinders Resistant Line (FRL) rats. Thus, there are a number of parallels between FSL rats and depressed humans. The FSL rats may be the first animal model of depression to mimic the actual trait of depression, and not just the state.     

Hormonal facilitation in the release of sperm from the spermatheca of the red-spotted newt

Summary Several neurotransmitters and hormones with potential to trigger a simultaneous contraction of the oviducts and the spermathecal myoepithelium were examined. Saline (0.05 ml), or 0.05 ml saline plus acetylcholine (9 mg), norepinephrine (50 g), arginine-vasotocin (25 units), prostaglandin F₂(3g) were injected into the spermathecal region of female newts (n=24 per group). The numbers of sperm present in the cloacae of prostaglandin-injected animals (107±30 SEM) were significantly greater than the numbers detected in saline (27±5 SEM) and in uninjected (14±3 SEM) controls. Smaller and less consistent increases in the numbers of sperm were detected in the vasotocin- and norepinephrine-injected groups. Study of sections from ovulating female newts failed to produce evidence that pressure from the passage of ova through the posterior portion of the oviduct forced sperm from the spermatheca. Observations indicate an active role for the spermathecal myoepithelium in the discharge of stored sperm and of a role for prostaglandin F₂ in triggering that discharge.     

Polypeptides of cerebral subcellular fractions of differentially-housed mice

Summary The difference in protein of cerebral nerve-ending fractions caused by differential housing of male mice is of a quantitative nature and might reflect a change in the number of nerve-endings.This work was supported in part by Centro Nacional Ramón y Cajal (de la Seguridad Social) and Fundación Juan March and was conducted in part at the Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan Italy, while Dr F. P. Conde was on a research fellowship. Thanks are due to Mr Riccardo Gelati for technical assistance and to Mr Mario Azzini for the photography.     

Effect of genome size andrrn gene copy numbers of PCR amplification products of 16S rRNA genes from mixed bacterial species

Results and conclusion As determined by image analysis of SYBR green-stained amplification products the experimentally determined ratio corresponded well with the expected ratio calculated from the number ofrrn genes per equimolar amount of DNA in mixtures containing DNA ofEscherichia coli and Thermus thermophilus and DNA ofPseudomonas aeruginosa and T. thermophilus. The values for the pairBacillus subtilis and T. thermophilus showed higher deviation from the predicted value. The dependence of the amount of 16S rDNA amplification products on these two parameters makes it impossible to quantify the number of species present in 16S rDNA clone library of an environmental sample, as long as these two parameters are unknown for these species.     

Effects of aluminium hydroxide on restraint-induced and restraint delay-induced gastric ulceration in rats

Summary Rats given aluminium hydroxide after cold-restraint stress but before the post-stress delay period, ulcerated significantly less severely and less frequently than rats given the drug before cold-restraint stress or those given water at either time period. Both aluminium hydroxide treated groups exhibited less ulceration than non-drug groups. These data suggest profound parasympathetic and hence, gastric acid, involvement in restraint delay-induced ulceration in rats.     

Protective effect of vitamins against trichothecene toxicity towardsSaccharomyces cerevisiae

Summary Several trichothecene mycotoxins were shown to inhibit the growth ofSaccharomyces cerevisiae. This effect was most pronounced with the macrocyclic trichothecenes, especially verrucarin A. Much less growth inhibition was observed with T-2 toxin. Verrucarol, diacetoxyscirpenol, acetyl T-2 toxin, HT-2 toxin, T-2 tetraol and neosolaniol were inactive at a concentration of 75 g of toxin per disc. Incubation ofS. cerevisiae with verrucarin A together with vitamins resulted in a decrease in toxicity. Pyridoxine-HCl, Ca-pantothenate, thiamine-HCl and -tocopheryl acetate were amongst the most potent of the vitamins tested which reversed growth inhibition, overcoming the inhibitory potential of the toxins.9 December 1986The authors thank Dr J. Behrend, Makor Company, Israel, for a generous gift of verrucarin A and roridin A.     

Structural characteristics and distribution of satellite cells along crayfish muscle fibers

The distribution of satellite cells (sc) in long-sarcomere muscle fibers from the carpopod extensor muscle of the crayfish (Astacus fluviatilis) has been studied electron-microscopically. The sc are spindle-shaped and are oriented parallel to the long axis of a fiber. The mean lengths of sc nuclei (17.00 m) and that of myonuclei (18.35 m) differ non-significantly. In older animals, the mean ratio of the number of sc nuclei to the total number of nuclei (sc nuclei + myonrclei) is 0.0716, 0.0848, and 0.034 for the tendon, central and shell segments, respectively. The corresponding values for younger animals are 0.158, 0.166, and 0.081. The mean numbers of sc nuclei per mm of a fiber are 94, 117, and 47 (older animals), and 164, 117, and 94 (younger animals) for the tendon, central and shell segments, respectively. The high incidence of sc per unit fiber length in crayfish may be related to the fact that crayfish muscle fibers have a much larger diameter than vertebrate muscle cells.     

Plasma and hepatic antioxidant control and vitamin A nutritional status

Twenty-seven rats were divided into three groups and fed on diets containing 0.3, 6 or 60 RE (retinol equivalent) retinyl palmitate/g food. After 7 weeks, hepatic vitamin A uptake was found to be more efficient in vitamin A-deficient rats than in rats given adequate vitamin A. We showed that during the metabolic adaptation of the animals to the level of vitamin A in the diet, extensive modifications occur in the antioxidant defences of the organism. In parallel with the increase in the level of vitamin A, the decrease in the level of -tocopherol in the plasma can bring about a greater susceptibility of the lipoproteins to oxidative stress. Similarly, the decrease in the hepatic -tocopherol level and in glutathione peroxidase activity leads to the weakening of the liver's antioxidant defences.     

Pancreastatin,a chromogranin A-derived peptide,inhibits leptin and enhances UCP-2 expression in isolated rat adipocytes

Leptin, the ob gene product, is an adipocyte-secreted hormone that centrally regulates weight by decreasing caloric intake and increasing energy expenditure. Expression of leptin is regulated by dietary status, insulin, glucocorticoids and catecholamines. Pancreastatin (PST), a chromogranin A-derived peptide, correlates with catecholamine levels, and may play a role in the physiology of stress, modulating endocrine secretion and metabolism. Thus, PST has been found to exert a lipolytic and anti-insulin effect in white adipocytes. The aim of the present work was to investigate a possible role of PST modulating the expression of key genes involved in lipid storage and metabolism: leptin, PPAR-2, UCP-1 and UCP-2. We incubated isolated rat epididymal adipocytes with 100 nM PST for 16 and 24 h. Leptin, UCP-2 and UCP-1 mRNA levels were assessed by RT-PCR, followed by Southern blot. Leptin secretion was also measured by ELISA. PST inhibited leptin expression and secretion at 16-h incubation, but this effect was no longer observed after 24 h. On the other hand, PST stimulated the expression of UCP-2 after 16 h. However, the effect was still significant after 24 h. The inhibitory effect of PST on leptin expression and secretion and the stimulation of UCP-2 expression were prevented by blocking PKC. UCP-1 and PPR-2 expression did not change after PST stimulation. Leptin differentially regulates the expression of key genes in the rat adipocyte, upregulating the expression of UCP-2 and inhibiting the expression and secretion of leptin by a mechanism that involves PKC activity. These effects may contribute to the metabolic action of catecholamines in physiological and pathophysiological conditions with increased sympathetic activity.Received 5 September 2003; received after revision 6 October 2003; accepted 14 October 2003     

Karyotype of South American pampas ofPseudalopex gymnocercus (Carnivora,Canidae)

Summary The karyotype of the pampas fox has 2n=74 and a NF=76. Except forChrysocyon brachyurus, 2n=74 is a common diploid number for the South American Canidae. This number is higher than in theVulpes group and lower than in the group of the typicalCanis. No marker chromosomes are present in the South American Canidae.     

Anti-bovineβ-lactoglobulin antibodies react with a human lactoferrin fragment and bovineβ-lactoglobulin present in human milk

Human milk samples react against anti-bovine-lactoglobulin rabbit antibodies, as measured by a competitive radioimmunoassay. Immunoreactivity was positive even in milk from mothers consuming a diet free of cow's milk. An increase with a diet rich in cow's milk proteins was detected by immunoelectrophoresis. The human milk fraction cross-reacting with anti-bovine-lactoglobulin antibodies corresponds to the 20 kDa fragment from the N-terminal end of human lactoferrin. Three regions of this fragment exhibit sequence homology with a sequence contained in cow's-lactoglobulin (between residues 124 and 141).     

Changes in water permeability of an insect egg in response to level of water in the environment

Summary The water permeability of eggs of the southern corn rootworm, Diabrotica undecimpunctata howardi Barber, varied depending on the previous experience of the eggs. Eggs acclimated in a water vapor system were seen to be less permeable than eggs acclimated in contact with moist paper, as measured by the rate of loss of water from the eggs and the susceptibility of the eggs to death from desiccation. This is the first known report of the ability of an insect egg to adapt to the level of water available in the environment.     

Some citrus chitinases also possess chitosanase activities

Several acidic chitinase and chitosanase isoforms were found in 4-week-old nonembryogenic sweet orange (Valencia [Citrus sinensis (L.) Osbeck]) callus tissue. Two isoforms (designated A1-CF1 and A1-CF2) were purified to homogeneity using HPLC size exclusion, anion exchange, and chromatofocusing techniques. Both hydrolase isoforms exhibited activity with either colloidal chitin or solubilized shrimp shell chitosan. Specific activities for the purified isoforms could not be calculated because of the lack of protein and contamination of ampholytes. However, the specific activities for chitinase and chitosanase after anion exchange were respectively 404 nmol GlcNAc per min per mg protein and 2,475 nmol GlcN per min per mg protein. The M_r for both enzymes was 30,500. The homogeneous proteins cross-reacted in western blots with antiserum against a basic class I potato leaf chitinase.     

Mapping and quantification of biomolecules in tumor biopsies using bioluminescence

Quantitative bioluminescence and single-photon imaging have been applied for mapping concentration distributions of metabolites, such as adenosine triphosphate (ATP), glucose and lactate, in biopsies of cervical cancers in patients. Biopsies were taken before a conventional radiation treatment, and a number of clinically relevant data, such as local tumor control, patient survival, metastatic spread and so forth, were documented. There was no correlation between staging or grading and any of the metabolic parameters measured. Local correlations between ATP, glucose and lactate on a pixel-to-pixel basis were generally positive, with respective Spearman's correlation coefficients less in patients without clinically documented metastasis compared with those with metastatic spread. Lactate concentrations were significantly higher and scattered over a wider range in tumors with metastatic spread in comparison to malignancies in patients without metastasis. Thus, high local lactate levels of 20 mole/g appear to be associated with a high risk of metastasis, at least in human cervical tumors.