Theophylline, otentiation of testosterone propionate or estradiol bensoate in inducing male but not female sexual behavior in the female rat.

Two experiments were carried out to assess the possible involvement of 3′:5′cyclic adenosine monophosphate (cAMP) in the hormonally mediated activation of masculine and feminine sexual behavior in female rats. In Experiment I, theophylline, a compound shown to be effective in inhibiting the degradation of cAMP, was combined with estradiol benzoate (EB) in an attempt to potentiate the action of estradiol for inducing feminine or masculine sexual behavior. Theophylline, when administered in combination with EB to ovariectomized females, resulted in an increase in masculine sexual behavior but no potentiating action on female receptivity. In Experiment II, theophylline, when given to female rats, potentiated the action of testosterone propionate in stimulating male but not female sexual behavior. These data suggest that estradiol and testosterone may be activating masculine sexual behavior through similar biochemical mechanisms. Likewise, cAMP may be involved in the activation of masculine but not feminine sexual behavior by gonadal steroids.     

Incidence of zearalenol (Fusarium mycotoxin) in animal feed.

Zearalenol, the reduction product of zearalenone produced by Fusarium roseum growing in cereals, was found for the first time naturally occurring in oats and corn. This metabolite is three to four times more active estrogenically than zearalenone.     

The influence of small atmospheric ions on human well-being and mental performance

Two experimental series were carried out to investigate a possible influence of small atmospheric ions on human beings under well-controlled conditions. In Experiment I, six female subjects were individually exposed in a climatic chamber to high concentrations of positive atmospheric ions, negative atmospheric ions and no ions. Physiological measurements were made, mental performances were tested and subjective votings were recorded. No significant effects of positive or negative atmospheric ions were found. — in Experiment II, 12 male and female subjects were selected out of 125 persons, all tested individually for feeling of discomfort when exposed to positive air ions in short selection experiments. These subjects were exposed twice to the same three ion conditions as in Experiment I. For the selected subjects no significant influence of the ions was found.Presented at the Second Colloquim Bioklimatische Wirkungen luftelektrischer und elektromagnetischer Faktoren, Technische Universität, Munich 16–18 September 1976.     

Perturbed angular correlation gamma ray (PAC) spectroscopy of 111Cd carboxypeptidase A alpha.

The active center of Cd(II) carboxypeptidase A has been examined by means of perturbed angular correlation of gamma rays as a function of pH. This method simultaneously detects changes in coordination geometry, in the charge of groups within 5 Å of the metal nucleus and delineates multiple states of the active center. Carboxypeptidase A crystals exhibit one predominant state while several are present in solution. Interpretation of the experimental data in terms of Angular Overlap Theory suggests the species characteristic of the crystals has a distorted tetrahedral coordination geometry and is in equilibrium with a pentacoordinated species in solution.     

Fine structure of somatotrophs and mammotrophs in the pituitary pars distalis of the little (lit) mutant mouse

The cellular pathology and postnatal differentiation of somatotrophs and mammotrophs in the pars distalis of little (lit/lit) and normal (+/+; lit/+) mice were studied by means of electron microscopy. The results indicate that in little the pituitary at birth contains recognizable somatotrophs and mammotrophs; however, between 14 and 24 days of age a contrast between little and normal becomes conspicuous with respect to the somatotrophs. Little somatotrophs are less heavily populated with granules, have granules of smaller size, and show less developed organelles than do normal somatotrophs at comparable stages. Beyond 24 days the little somatotrophs become more difficult to locate, and those that do occur show a minimal increase in complexity from that present at 14 days. In contrast, the mammotrophs in little are similar in appearance to normal mammotrophs and show increasing complexity as development proceeds, often sending forth cellular processes between neighboring cells, as do normal mammotrophs.     

Stereoscan studies of eggs, free-swimming and penetrating miracidia and early sporocysts of Fasciola hepatica.

The egg of Fasciola hepatica has a smooth surface with a slightly elevated circle marking the fracture of the operculum. The operculum and the aperture have crenated edges. The epithelial cells of the miracidium are covered with long cilia. When miracidia are vibrated in an ultrasonic cleaner the cilia of the epithelial cells of the four posteroir tiers are broken off only leaving longitudinal rows of cilium stubs, whereas the cilia of the first tier are still retained. The apical papilla is provided with a dorso-ventral furrow, multiciliated pits and isolated sensory cilia. The narrow intercellular ridge is smooth, whereas the epithelial cells have small cytoplasmic knobs between the cilia. The penetration into the snail (Lymnaea truncatula) and the transforamtion into sporocyst may be separated into three phases. (1) Less than 1 min after attachment to the snail the ciliated cells of the anterior tier are shed and swim away. (2) The cilia of the remaining cells beat violently and after about 5 min most cilia are broken off near the cell surface. The miracidium remains for about 15 min embedded as far as the intracellular ridge receptors (lateral papillae and sheathed ciliated nerve endings). During this period extensive contraction and relaxation of the body are performed. (3) The final penetration of the snail epithelium takes about 15 min. Simultaneously with the penetration into the snail tissue the "bald" cells (epithelial cells with cilium stubs only) of the four posterior tiers loosen, florm globules and fall off. The surface below the cells is smooth and in cytoplasmic continuity with the intercellular ridge and the apical papilla, and this syncytium forms the later tegument of the sporocyst. After a few days the tegument of the sporocyst is provided with microvillus-like projections and the apical papilla and sensory structures are lost.     

Mutagenesis by O6 meG residues within codon 12 of the human Ha-ras proto-oncogene in monkey cells.

The first or/and the second guanines of the human Ha-ras codon 12 (normally GGC) were substituted by O6 meG residues and the modified sequence was subsequently introduced into an SV40-based shuttle vector able to replicate in both simian cells and bacteria. After replication in simian COS7 cells (proficient in O6-alkyl-guanine transferase), plasmid DNA was extracted and mutations were screened in E. coli DH5 alpha cells. The vast majority of the mutations induced by O6 meG were G----A transitions. The mutation frequency observed at the second guanine of codon 12 (12G2 position: 3.75% +/- 0.4) was higher than the one observed at the first guanine (12G1 position: 1.09% +/- 0.6). This difference was confirmed by the results obtained when two adjacent O6 meG residues were positioned within codon 12. The higher mutation frequency observed for the 12G2 position could be attributed to differential repair or/and variation in polymerase fidelity. These results are in agreement with animal experiments where alkylating agents gave rise to mutation on G2 position of codon 12.     

Cellular autophagy in proximal tubules of early diabetic rats following insulin treatment and islet transplantation

The influence of insulin treatment (group 1) and allogenic islet transplantation (group 2) on renal cellular autophagy were evaluated in adult Lewis rats in the early phase of streptozotocin-induced diabetes mellitus—a condition in which autophagy is inhibited and renal mass is increased. Three days after insulin treatment or islet transplantation (IT), the right kidney was resected and cortical tubular tissue was examined by quantitative electron microscopy. In group 1, the volume and numerical densities of autophagic vacuoles (AVs) increased by 70% and 80% respectively in the proximal tubular cells compared with saline-injected controls. The additive effect of unilateral nephrectomy (Ux) on cellular autophagy was investigated 1 or 2 days after Ux. Compared with the resected right kidney, the volume and numerical densities of AVs in the remnant left kidney decreased by 49% and 43% in the insulin-treated rats, and by 43% and 39% in the saline-injected diabetic animals. In group 2, the volume and numerical densities of AVs increased by 45% and 44% in parenchyma regressing from diabetic hypertrophy after IT, compared with sham-operated controls. After Ux, the volume and numerical densities of AVs decreased by 49% and 43% in IT rats, and by 41% and 53% in the still diabetic sham-operated animals. The data show that inhibition of cellular autophagy in the proximal tubules of the early diabetic kidney can be reversed by insulin replacement, despite the fact that insulin per se inhibits cellular autophagy in the nondiabetic kidney. Thus the stimulation of cellular autophagy in the diabetic kidney by insulin replacement may be an important mechanism in the regression of diabetic renal hypertrophy. Both the diabetic kidney and the kidney regressing under the influence of insulin respond to the additional growth stimulus of Ux by inhibition of cellular autophagy.