Timing of single daily meal influences relations among human circadian rhythms in urinary cyclic AMP and hemic glucagon,insulin and iron

Summary Relations among circadian rhythms in serum iron, glucagon and insulin and urinary cyclic AMP excretion differ drastically when diurnally active, nocturnally resting human adults consume all daily food for one week as breakfast only and for another week as dinner only—a finding of interest to diverse fields, e.g., for optimizing certain kinds of therapy or for a better utilization of calories.Supported by grants (No. RR-400 from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health, USPHS and Nos. 5-K6-GM-13, 981 and 1RO1-CA-14445-01) and grant No. 20, Fondation de l'industrie pharmaceutique pour la recherche.     

Demonstration of a basal lamina in cocultures of thyroid cells and embryonal swine skin cells]

Porcine thyroid and embryo skin cells were isolated and cultured. Cultures from each kind of cells, as well as cocultures were fixed twice a week for electron microscopy. On day 8th a basal lamina like material appears only in the cocultures, along the basal plasmalemma of the reassociated thyroid cells. This amorphous material increases up to day 17th.     

Imprinting of the Peking duck (Anas platyrhynchos) and dependence on exposure to light during ontogenesis

Embryos of Peking ducks were either incubated in complete darkness up t o hatching or were put into light one week before hatching. Control embryos were incubated under dim light conditions which corresponded broadly to the natural conditions. Under standardized imprinting conditions the controls and both groups of the light deprived ducklings showed the 'following response'. Most of the dark-incubated embryos, however, did not distinguish between imprinting and test objects of different shapes. Since most of the embryos kept in darkness only for 21 days also failed to develop the capacity for shape discrimination, there is apparently a critical period for light influences on the development of this capacity at some time during the early prenatal period.     

Smooth muscle cells in ‘venous patches’ grafted into the rat common carotid artery. A structural study

Summary In the 2nd week after surgery, well differentiated smooth muscle cells (SMC) were evident in the walls of venous patches in rat common carotid artery. Gap junctions were the only type of intercellular junction observed between SMC in the present study.In memoriam to Prof. J. Cabré Piera.Acknowledgment. The LKB IV ultramicrotome was purchased with a grant from the Banco Urquijo, Madrid (Spain). Authors are also grate to M. Guerricabeitia for technical assistance.     

Permissivity of the rat (Rattus rattus) of Guadeloupe with regard to Schistosoma mansoni and evidence for migration of adult schistosomes to the lungs]

In contrast to the laboratory Rat, the Rat (Rattus rattus) of Guadeloupe is a favorable host for the life cycle of S. mansoni: the parasite population is maintained at a high level (between 8 and 16% in this host until the 16th week and reproduces normally). The evolution of the parasitose is marked, shortly after the 8th week, by a transfer of schistosomes from the liver to the lungs.     

35S-sulphate incorporation into myelin sulphated mucopolysaccharides during rat brain development.

Rat brain myelin acid mucopolysaccharides (AMPS) incorporate 15%, 8%, 5.5% and 4% of total associated 35S-sulphate, 14, 21, 30 and 75 days after birth, respectively. The course of 35S-sulphate incorporation into total rat brain mucopolysaccharides, as well in those from myelin, had a similar feature with peak on the 2nd week and a significant decrease on the 3rd and 4th week postnatally.     

Developmental characteristics of histamine methyltransferase and phenylethanolamine-N-methyltransferase of rat brain

Summary The specific activity of histamine methyltransferase of rat brain increases rapidly from the 16th until the 25th day of gestation (7 days after birth). The specific activity of phenylethanolamine-N-methyl-transferase shows a rapid incrase during the 1st and the 2nd week after birth, the adult values being obtained by the end of the 2nd week.     

Modeling melanoblast development

Melanoblasts are a particular type of cell that displays extensive cellular proliferation during development to contribute to the skin. There are only a few melanoblast founders, initially located just dorsal to the neural tube, and they sequentially colonize the dermis, epidermis, and hair follicles. In each compartment, melanoblasts are exposed to a wide variety of developmental cues that regulate their expansion. The colonization of the dermis and epidermis by melanoblasts involves substantial proliferation to generate thousands of cells or more from a few founders within a week of development. This review addresses the cellular and molecular events occurring during melanoblast development. We focus on intrinsic and extrinsic factors that control melanoblast proliferation. We also present a robust mathematical model for estimating the doubling-time of dermal and epidermal melanoblasts for all coat color phenotypes from black to white.     

Immunofluorescent localization of beta-lipotropin (beta-LPH) and beta-endorphins in normal and anencephalic human fetal pituitary gland]

The use of antibodies to alpha-(17-39) ACTH, beta-LPH, alpha- and beta-endorphins has enabled the detection of immunoreactive cells in human fetal pituitary glands as early as the eight week of gestation. The same cells reacted with the different antibodies. Immunoreactive cells were also observed in the pituitary of 6 human anencephalic fetuses.     

35S-Sulphate incorporation into myelin sulphated mucopolysaccharides during rat brain development

Summary Rat brain myelin acid mucopolysaccharides (AMPS) incorporate 15%, 8%, 5.5% and 4% of tojtal associated³⁵S-sulphate, 14, 21, 30 and 75 days after birth, respectively. The course of³⁵S-sulphate incorporation into total rat brain mucopolysaccharides, as well in those from myelin, had a similar feature with peak on the 2nd week and a significant decrease on the 3rd and 4th week postnatally.     

Dietary n-3 polyunsaturated fatty acids and coronary heart disease-related mortality: a possible mechanism of action

Epidemiological and interventional studies indicate that dietary n-3 PUFA reduces mortality due to coronary heart disease (CHD). They act at a low dose, since one or two meals with fatty fish per week is sufficient to provide protection when compared with no fish intake. These fatty acids are effective in providing primary prevention in low- and high-risk subjects and secondary prevention. At high doses, dietary n-3 PUFAs have several beneficial properties. First, they act favourably on blood characteristics: they are hypocholesterolemic and hypotriglyceridemic; they reduce platelet aggregation; they exhibit antithrombotic and fibrinolytic activities; they reduce blood viscosity and they exhibit antiinflammatory action. Second, they reduce ischemia/reperfusion-induced cellular damage. This effect is apparently due to the incorporation of eicosapentaenoic acid in membrane phospholipids. Third, they reduce ischemia and reperfusion arrhythmias. All the effects exerted by n-3 PUFAs at high doses are incompatible with the beneficial action on CHD mortality in humans observed at low doses, where their main properties are related to circulation in the form of free fatty acids. Numerous experimental studies have indicated that low concentrations of exogenous n-3 PUFAs reduce the severity of cardiac arrhythmias. This effect is probably responsible for the protective action of n-3 PUFA on CHD mortality. Further studies are necessary to confirm this assumption in animals. Such studies should take account of the fact that only a low dose of n-3 PUFA (20 mg/kg/day) is necessary to afford protection. Furthermore, since the beneficial effect of n-3 PUFAs on CHD mortality is observed in fish eaters versus no-fish eaters, and since populations in industrialised countries consume excess n-6 PUFAs, control animals in long-term dietary experiments should be fed a diet with only n-6 fatty acids as a source of PUFAs.     

Evidence for the existence of 2 types of α1-lipoprotein in amniotic fluid from pregnancies older than 20 weeks

Summary We have found by means of crossed immunoelectrophoresis that amniotic fluid contains 2 types of ₁-lipoprotein after the 20th week of pregnancy. Before that period the ₁-lipoprotein profile of amniotic fluid resembles that of serum and migrates as one type only.     

Antifertility activity of trimethylphosphate in male rats

Summary The toxic effect of trimethylphosphate on rat testes was investigated after oral dosing with 250 mg/kg for either 5 days/week for 30 days or 6 days/week for 60 days. After these prolonged treatments azoospermia resulted.Acknowledgments. The authors wish to thank Ms M. Michelles, Ms A. Murray and Ms R. Peake for their technical support.     

Differential effects of disuse preceding denervation on the onset and development of fibrillation in fast and slow muscles

Summary Section of the sciatic nerve, performed after a week of muscular disuse, is followed by fibrillation earlier in the soleus (S) than in the anterior tibialis (AT) muscle of the rat. The subsequent development of fibrillation, which is different in the control denervated S as compared with the control denervated AT, tends to become similar in the disused-denervated muscles.This work was aided, in part, by a grant from U. I. L. D. M. (Unione Italiana Lotta alla Distrofia Muscolare), Sezione di Trieste.     

Imprinting of the Peking duck (anas platyrhynchos) and dependence on exposure to light during ontogenesis

Summary Embryos of Peking ducks were either incubated in complete darkness up to hatching or were put into light one week before hatching. Control embryos were incubated under dim light conditions which corresponded broadly to the natural conditions. Under standardized imprinting conditions the controls and both groups of the light deprived ducklings showed the following response. Most of the dark-incubated embryos, however, did not distinguish between imprinting and test objects of different shapes. Since most of the embryos kept in darkness only for 21 days also failed to develop the capacity for shape discrimination, there is apparently a, critical period for light influences on the development of this capacity at some time during the early prenatal period.Acknowledgments. We are grateful to Dr E. Pröve for his advice on the carrying out of our imprinting tests, to K. Weigel for help with the drawings and to Dr. J. R. Wolff for helpful discussions.     

Maternal stress alters monoamine metabolites in fetal and neonatal rat brain

Heat-restraint stress given rats during the last week of gestation significantly altered dopaminergic dihydroxyphenylacetic acid and homovanillic acid (DOPAC and HVA) and noradrenergic 3-methoxy-4-hydroxy-phenyl-ethylene glycol (MOPEG) forebrain-hypothalamic monoamine (MA) metabolites in female offspring. On gestational day 21, HVA and MOPEG were significantly higher and lower, and on postnatal day 1 all were higher. There were virtually no differences in brain MA concentrations in males. Thus MA metabolic concentrations differ in fetal-neonatal forebrain-hypothalamus as a function of sex differences and maternal stress.     

Maternal stress alters monoamine metabolites in fetal and neonatal rat brain

Summary Heat-restraint stress given rats during the last week of gestation significantly altered dopaminergic dihydroxyphenylacetic acid and homovanillic acid (DOPAC and HVA) and noradrenergic 3-methoxy-4-hydroxy-phenyl-ethylene glycol (MOPEG) forebrain-hypothalamic monoamine (MA) metabolites in female offspring. On gestational day 21, HVA and MOPEG were significantly higher and lower, and on postnatal day 1 all were higher. There were virtually no differences in brain MA concentrations in males. Thus MA metabolic concentrations differ in fetal-neonatal forebrain-hypothalamus as a function of sex differences and maternal stress.     

Effects of centrophenoxine,piracetam and hydergine on rat brain lipid peroxidation

Summary The cerebral insufficiency improvers centrophenoxine, piracetam and hydergine were tested for their effect on lipid peroxidation of rat brain homogenates, both in vitro and in vivo. There was no effect either in vitro or after chronic 8 week dosing of animals.     

Effects of CO2 exposure on distribution of various forms of iron and copper in guinea-pig tissues

The effects on iron and copper distribution and metabolism of exposure to high levels of CO2 were studied in the guinea-pig. Mature, male animals were placed in an atmosphere of 15% CO2, 21% O2 (balance N2), and sacrificed from 1 h to 1 week thereafter. Total iron and copper concentrations of blood, liver, spleen and bone, as well as concentrations of heme and ferritin iron, were measured together with blood hematocrit, reticulocytes, plasma hemoglobin, plasma ceruloplasmin and copper concentrations. The results show clearly that rapid and sustained red cell damage or hemolysis ensued several h from the start of CO2 treatment. This resulted in loss of iron and copper from the blood, an influx of both elements into liver, spleen and bone, and a rise in plasma ceruloplasmin. Influx of iron into liver and spleen caused an accumulation of ferritin, the main site for iron storage in cells. Following the effect on red cells, there was an accumulation of heme iron, and a decreased hematocrit, best explained by a depressed activity of the reticuloendothelial and erythropoietic systems. A period of adaptation succeeded these events, in which all blood parameters and most tissue values returned to normal, despite the continuing presence of high CO2. The only changes not reversed were the elevations in liver, spleen and bone iron stores. These remained high, with a net accumulation of greater than 2 mg iron, or 3-4 times more than originally present. The results indicate that at least in the guinea-pig, high CO2 exposure results in red cell damage and other events leading to an accumulation of additional iron in the body; also, that iron accumulated as ferritin and hemosiderin in liver and spleen may not be readily available to restore blood hemoglobin concentrations on an acute basis.     

Effect of light on variations in blood testosterone in the ram: demonstration of a photosensitive phase in diurnal rhythm]

6 groups each of 5 adult rams were subjected in light controlled pens to a pretreatment of normal variations in daylength during May and June. Then one group followed the normal daylength and the other five different "skeleton photoperiods" of 8 hrs of light per day consisting of: 7 hrs continuous light (7 L) + 1 hr light (1 L) situated at different times of the dark period (D) according to groups. Blood samples were taken once each week and hourly during one 24 hr period in June, July and September. Peripheral plasma testosterone measured by radio-immunoassay was used as an index of testicular activity. There was increase in the level of testosterone resuting from a rise in the number of peak release during the 24 hrs. In the different light treatments tested, only the treatment (7L+9D+1L)+7D) stimulated testosterone secretion with the pattern of testosterone of this group being similar to that of the control group. This indicates that there exists a photosensitive phase at 16 to 17 hrs after the beginning of the principal light (the subjective dawn).