Ontogeny of endocrine responses to methadone in rats

The effects of methadone (METH) on serum levels of prolactin (PRL), growth hormone (GH), corticosterone (CS) and TSH were determined in developing rats. METH increased PRL, GH and CS and decreased TSH at all ages tested, but the time course and magnitude of these effects changed during ontogeny. METH effects on day 10 were lower in magnitude than those observed in adults. In 20 day old pups, METH effects on GH and CS were comparable to those of adults, but TSH effects were still blunted. METH effects on hormone secretion in both 10 and 20 day old pups lasted longer than those observed in adults. Naloxone blocked all hormonal responses in adults, but did not completely block METH effects on CS secretion in 10 day old pups.     

Different structure of polytene chromosomes ofPhaseolus coccineus suspensors during early embryogenesis

Summary The pattern of DNA and RNA puffs in pair VII of polytene chromosomes has been investigated in the suspensor ofPhaseolus coccineus during early embryo development. The pattern of³H-TdR and³H-U incorporation has been also detected. Collected data indicate that: 1. both heterochromatic regions, p₁₁ and q_(111+112), of chromosome pair VII, organize large DNA puffs; 2. DNA puffs of both regions are specific of different embryo differentiation steps; 3. a seasonal influence on the DNA puffing seems also to be present, as demonstrated by the comparison of the results collected in two different crops; 4. the incorporation experiment by³H-TdR evidences that not all DNA puffs show clustered labeling; 5. the RNA puffing of the two regions seems also to be specific of determined embryo stages.     

The Relationship between Cell Membrane Potassium Ion Transport and Glycolysis : The effect of ethacrynic acid

Cell membrane transport of K⁺ stimulates the rate of glycolysis in Ehrlich ascites tumor cells. A study of the characteristics of this relationship indicates that the stimulation occurs under anaerobic as well as under aerobic conditions. The data suggest that glycolysis is stimulated by a K⁺ transport mechanism that is coupled to Na⁺ transport because the effect is blunted or abolished when the principal intracellular ion is lithium or choline. This stimulus to glycolysis is blocked by ouabain and ethacrynic acid, agents that have been shown to inhibit monovalent cation transport in erythrocytes. In contrast to the action of ouabain, glycolysis is inhibited by ethacrynic acid in Ehrlich ascites tumor cells in the absence of cell membrane K⁺ transport. In studies with ghost-free hemolysates of human erythrocytes and with cytosol prepared from Ehrlich ascites tumor cells, ethacrynic acid significantly blocks lactate formation from fructose diphosphate demonstrating the direct inhibitory effect of this agent on one or more enzymes of the Embden-Meyerhof pathway. Since ethacrynic acid has no influence on lactate formation in intact erythrocytes utilizing an endogenous substrate, the presumptive site of inhibition is proximal to the 3-phosphoglycerate level.     

COMPARISON OF THE BEHAVIOUR OF A SOLUBLE AND A MEMBRANE-BOUND ENZYME IN TRANSECTED PERIPHERAL NERVES

Phosphoglucoisomerase (PGI), a soluble enzyme, and AChE, a membrane-bound enzyme were studied in transected peroneal nerves of dog and in isolated segments of these nerves. Although activities of both enzymes increased at the ends of transected nerves, marked differences in their behaviour were observed. The increment in AChE activity was much sharper than that of PGI and continued to grow with time whereas the increase in PGI developed fully within the initial hours after transection and did not change thereafter. In an isolated nerve segment AChE accumulated at both ends with a concomitant decrease in the middle part, whereas changes in PGI activity appeared only in the terminal parts, the rest of the nerve remaining at the normal level. The terminal increase of PGI did not, contrary to that of AChE, depend on the length of the isolated segment. The changes in PGI activity may be features of a local peritraumatic reaction whereas those of AChE indicate involvement of the whole segment along which the enzyme containing organelles are transported.     

Effects of nitrogen,phosphorus and potassium fertilizers on the assimilation capacity ofBeta vulgaris chloroplasts (I)

Summary Aspects of non-cyclic photophosphorylation and NADP photoreduction,viz (a) the effects produced on these processes by the three fertilizer elements: nitrogen, phosphorus and potassium; (b) variations in the catalase activity of reaction mixtures following fertilizer application, and (c) correlations between photosynthesis as measured on leaf-tissue discs and the assimilation capacity of chloroplast suspension, were studied. The role of catalase in the non-cyclic photophosphorylation processes was also studied.While photophosphorylation is influenced chiefly by the level of available soil phosphorus, NADP reduction is affected by all three nutrients. In addition, there was a greater degree of significance, for diagnostic and application purposes, in the values obtained if these two activities were referred to the chloroplast count rather than to the chlorophyll content.Catalase activity, in addition to responding in a different way to the respective fertilizer treatments and, in particular to available soil nitrogen, was governed by the principal constituents of the reaction mixture and in a manner contrary to that of non-cyclic photophosphorylation as measured in terms of oxygen evolution.Experimental findings further showed that photosynthesis is correlated chiefly with NADP-reduction capacity.     

Reduction of a Tetrazolium Salt in Determining Growth Activity of Yeast-Phase Histoplasma capsulatum

A colorimetric method using a tetrazolium compound, 3,4,5-dimethylthiozalil-(1 or 2),2,5-diphenyltetrazolium bromide (TTBr), was developed for studying the growth activity of yeast-phase Histoplasma capsulatum. Materials extracted in phosphate buffer, pH 7.0, from cells at different stages of growth reduced TTBr. Colorimetric changes were correlated with enzymatic activity. Under standardized conditions specified herein, the optical density of the reduced tetrazole was an index of the growth activity of the organism.     

About phoma liliana Chandra & Tandon

Summary In vitro,Phoma liliana could not be distinguished from the later-describedP. ehretiae and two incidental isolates fromMangifera andChrysanthemum. Starting from the principle of the classification in the Deuteromycetes, our conclusion is that we must speak of one and the same form-species, which can be found on different plants.     

Studies on several genetic hematological traits of the Mexican population. XII. Distribution of blood group antigens in twelve Indian tribes

Blood samples from 1090 Mexican Indians belonging to the Chol, Chontal, Totonac, Huastec, Mixe, Mazatec, Zapotec, Mixtec, Chinantec, Nahua, Cora and Huichol linguistic groups, were obtained and examined in regard to the following blood group antigens: A, B. M, N, P, C, c, D, E, e, Fy(a), K and Di(a). The gene frequencies were similar to what has been described for other Amerindians; high values for O, M, CDe, cDE and Duffy; low to absent Kell and presence of Diego in variable amounts. The frequency of chromosomes CDE and cDe/cde was somewhat higher than usual and some of the tribes had relatively high frequencies of the A and B antigens. It was felt that variable degrees of non-Indian admixture was at least partially responsible for this situation. A previous study dealing with the distribution of abnormal hemoglobins and glucose-6-phosphate dehydrogenase deficiency in these same tribes, had strongly suggested the possibility of some Negro admixture in the Chontal, Nahua and Cora tribes. However, this was not specifically reflected in their blood group distribution. This served to emphasize the need of investigating as many markers as possible when trying to characterize a population.     

Die Wirkungsweise von Cercosporella herpotricboides Fron, dem Erreger der Halmbruchkrankheit des Getreides

In halt: 1. Einleitung und Aufgabenstellung.—2. Art und Ausmaß der Scnäden im Feld-versuch.—3. Wirkungen des Krankheitserregers auf Sommergetreide.—4. Bekämpfungsmöglichkeiten.—5. Besprechung der Ergebnisse.—Zusammenfassung.—Summary. —Literaturverzeichnis.