Plasma thyroxine levels in Duchenne muscular dystrophy

Some young Duchenne muscular dystrophy (DMD) patients (3-7 years) had total thyroxine (T4) levels and T4 to thyroxine binding globulin (TBG) ratios above the normal range and significantly increased free thyroxine indices (fT4I) which, however, remained within the normal range. Older DMD patients (7-11 years) had T4 and TBG levels and fT4I similar to normal. In both DMD groups the thyroxine binding index (TBI) values were in the normal range.     

Formation of cutaneous nerve trunks in the chick. Ultrastructural and quantitative analysis]

In chick skin structuration of nervous trunks takes place at 14-15 days of incubation, at the time of formation of the adult pattern of cutaneous innervation. At this same stage, myelogenesis begins, but develops mainly after hatching: only 4% of axons are myelinated at hatching, 40% in 6-week old Chickens and 60% in adults. This "critical" stage (14-15 days of incubation) apparently corresponds to the stabilization of cutaneous nerve supply.     

Development of post-hatching melatonin rhythm in zebra finches (Poephila guttata)

We examined levels of melatonin in the pineal, eyes and plasma over a 24 h period during development in the altricial zebra finch. Beginning as early as 2 days after hatching there was a distinct 24 h rhythm in melatonin in the pineal and plasma. Beginning at day seven after hatching there was also a 24 h rhythm present in the eyes. In the pineal and eyes the amplitude of the 24 h rhythm increased with age. In contrast, the amplitude of the plasma melatonin rhythm at 2 days was already within the range of adults and did not increase with age. These results confirm and expand earlier findings in the European starling and parallel those from precocial birds indicating that the circadian system is already competent at or shortly after hatching even in atricial birds.     

Annual cycle of plasma testosterone and thyroxine in the European badger (Meles meles L.)]

In the male European Badger there are important variations in the plasma testosterone and thyroxine levels during the annual cycle. During the summer, plasma testosterone concentrations are low while plasma thyroxine rises to a very high level. In winter, when the thyroid activity is minimal, testicular activity increases. From February to May, the plasma testosterone remains at a high level, and then, after a sudden fall, a second peak occurs in June at which time the concentration of thyroxine is low.     

Variation in the specific activity of intestinal DNA in Alytes obstetricians larvae (Amphibia, Anura) treated with thyroxine]

Treatment by thyroxine modified the specific activity of intestianl DNA in premetamorphic Alytes tadpoles. The activity decreased up to the 3rd day, and showed afterwards a peak which culminates on the 9th day. These results have been discussed in comparison with previous radioautographic observations.     

Effects of photoperiod, temperature and testosterone-treatment on plasma T3 and T4 levels in the Djungarian hamster, Phodopus sungorus

The effects of photoperiod, temperature and testosterone treatment on plasma T3 and T4 levels were investigated in the Djungarian hamster. Plasma T3 level was affected by temperature (25 degrees C less than 7 degrees C) but not by photoperiod. Plasma T4 level was affected by photoperiod (short day less than long day) at 25 degrees C. Administration of testosterone increased plasma T4 level under short photoperiod at 25 degrees C. Thus, higher plasma T4 level under long photoperiod at 25 degrees C might be induced by testosterone.     

Evolution de la mortalité et des malformations des embryons de Poulet incubés artificiellement

Summary During artificial incubation the chick embryos show a 30% mortality with the above mentioned material (incubator and breed of chicken). The 2 critical periods for the embryos are the first 5 days of incubation and the 2 days of hatching. In the same experience, the author found 4% of malformed embryos. All the values are calculated on the total of 503 fertile eggs. The author believes that the above mentioned figure represents a standard curve for a definite material.     

Quantitative Bestimmung von RNS-Fraktionen im Gehirn frisch geschlüpfter Bienen (Apis mellifica)

Summary In the brain of the honeybee (Apis mellifica), it was found that the rRNA content decreases rapidly during the first 2 days of adult life. An increase is observed from days 3 to 5, followed by another decrease to a level inferior to that of day 2 to 3. Except for a rise on the 5th day, 4s RNA remains constant. An unidentified RNA fraction of low molecular weight (D) sharply decreases on day 5. The possibility is discussed that these results reflect changes in RNA metabolism that can be related to the sequences of activity observed in the bees during the first 9 days after hatching.     

The ontogeny ofa-foetoprotein in the chicken

Summary The ontogeny ofa-foetoprotein (AFP) has been studied in the chicken using polyacrylamide gel gradient electrophoresis and electroimmunoassay from 7 days of incubation until after hatching. The results are discussed in the light of previous on the ontogeny of AFP in mammals.     

Effects of bilateral lesions of the nuclei habenulae on plasma thyroxine levels in Japanese quail.

Electrolytic bilateral lesions of th nuclei habenulae were made in male, adult photostimulated quail. Habenular destruction led to a marked decrease in the plasma thyroxine level (40%), whereas sham operated birds did not differ from controls. This result appears to be somewhat different from those obtained in mammals and the mechanisms of habenular-thyroid interrelationships are unknown.     

Plasma thyroxine levels in Duchenne muscular dystrophy

Summary Some young Duchenne muscular dystrophy (DMD) patients (3–7 years) had total thyroxine (T₄) levels and T₄ to thyroxine binding globulin (TBG) ratios above the normal range and significantly increased free thyroxine indices (fT₄I) which, however, remained within the normal range. Older DMD patients (7–11 years) had T₄ and TBG levels and fT₄I similar to normal. In both DMD groups the thyroxine binding index (TBI) values were in the normal range.     

Seasonal variations in the blood testosterone and thyroxine levels in the hedgehob (Erinaceus europaceus L)]

In adult male European Hedgehogs, which were studied outdoors, the plasma levels of both testosterone and thyroxine exhibited a marked annual cycle with a minimum in autumn and a maximum during spring and summer. The winter resumption of the testicular activity started already during the phase of hibernation and was concomitant with an increase of the plasma thyroxine level. The plasma titers of the two hormones dropped down together in August. The correlation between both hormones was less close from May through July.     

Changes in placental permeability to corticosterone and estradiol-17beta toward the end of gestation in the rat

Radioactivity in the fetal plasma 1 h after maternal injection of 14C-4-corticosterone or 14C-4-estradiol-17 beta on day 21 of gestation was markedly higher than that 1 h after injection on day 22. Radioactivity in the maternal plasma was not different on these 2 days. The results suggest that the placental permeability to steroids from the mother to the fetus declines toward the end of gestation in the rat.     

The effects in vivo of some sex hormones on the growth of tibias of normal and chondrodystrophic (Creeper) chick embryos]

Various sex hormones (testosterone, oestradiol, dehydroepiandrosterone), in the form of suspensions in oil, are injected into the allantois of normal and chondrodystrophic (Creeper) chick embryos of 6 days 1/2 incubation. Observations made on each of the phenotypes on the 12th day of incubation show that oil injected alone causes a significant decrease in the dry weight of the tibiae. This inhibitory effect is partially abolished when the oil is injected together with the sex hormones, testosterone being the most effective.     

Nerve endings isolated from chick embryonic optic tectum. 1. Developmental aspects of intact synaptosomes

Summary Fractions enriched in nerve endings (synaptosomes) have been isolated from optic tectum of chick embryos at 16 and 18 days of incubation and of chicks immediately after hatching. Morphological aspects of nerve endings have been examined with special regard to the appearance of synaptic thickenings and synaptic vesicles.     

L'aorte de l'embryon de poulet: histogénèse,cultures organotypiques,stimulations expérimentales

Summary The authors studied the structure of the aortic wall of chick embryos during embryonal development and after hatching up to the age of 1 month. The typical morphology appears on about the seventh day of incubation; it is established on the twelfth day and it does not change afterwards, there is only an increase in the relative quantities of its morphological components. The aorta is of muscular type in its caudal half, while its cranial half is elastic. The cultures of the elastic cranial half and of the muscular caudal half gave the same results already obtained from the explantation in vitro of elastic arteries (anonyma and pulmonary arteries) and of muscular arteries (carotid).

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Ces recherches ont été faites grâce à un subside du Fonds National Suisse de la Recherche scientifique et de la Fondation E. Barell de la Maison Hoffmann-La Roche SA, Bâle.     

Thyroid function parameters during a selenium repletion/depletion study in phenylketonuric subjects

Phenylketonuric (PKU) subjects have a limited supply of selenium (Se) in their phenylalanine-restricted diet. A Se repletion (1 g Se/kg/day)/depletion study was conducted in PKU children to determine the effect of Se on thyroid function parameters.The initial plasma Se concentration (mean±SD: 0.26±0.12 mol/L, p<0.00003, n=10) and glutathione peroxidase (GSH-Px) activity (140±58 U/L, p<0.00003, n=10) were significantly lower compared to agematched controls. After 14 weeks of supplementation, the plasma Se concentration (mean ±SD: 0.74±0.20 mol/L) normalized (normal range: 0.57–1.15 mol/L, mean ±SD: 0.76±0.13 mol/L, n=32) and remained stable thereafter during repletion. Plasma GSH-Px activity reached normal values after 18 weeks of supplementation (312±57 U/L; normal range: 238–492 U/L, mean ±SD: 345±54 U/L, n=32) and increased significantly for up to eight weeks thereafter (332±52 U/L). Individual and mean thyroid parameters were initially normal in all cases. The mean concentrations of plasma thyroxine (T₄: p<0.025), free T₄ (FT₄: p<0.01) and reverse triiodothyronine (rT₃: p<0.005) decreased to 75% of their initial value within three weeks of Se supplementation and remained stable thereafter, within a normal physiological range during selenium supplementation. They increased back to their initial values three weeks (T₄: p<0.05, FT₄: p<0.05) and six weeks (rT₃: p<0.025) respectively, after the end of the supplementation. In conclusion, Se supplementation modifies thyroid function parameters in Se-deficient PKU subjects most likely by an increase in activity of type I 5-deiodinase (5-DIase I).Preliminary results of this study were presented as posters on the 4th International Congress on Trace Elements in Medicine and Biology, Chamonix, France (1993) and the 4th Joint Meeting of the Lawson Wilkens Pediatric Endocrine Society and the European Society for Paediatric Endocrinology, San Francisco, California, Ped Res (1993) 33: S93 (abstract 537). Support in part by Research Grants of Nutricia BV, (The Netherlands).     

Weight changes in the eggs of Leucophaea maderae Fabr. (Insecta, Dictyoptera)]

Eggs in Leucophaea maderae are present in an ootheca which remains in the broodsac until hatching of the larvae. During incubation, the water content of the eggs increases from 36 to 77%, the dry weight remaining constant. Water is possibly provided by the mother.     

Steady-state distribution of lithium during cultivation of dissociated brain cells

Summary The formation of a steady-state intracellular lithium level was studied in the course of cultivation of dissociated nerve cell cultures obtained from chick embryonic brains. When lithium was given at a concentration of 2 mM, in the nutrient medium, at day 5, a steady state intracellular lithium content was achieved after about 30 min of incubation and it did not change significantly during the time of cultivation up to the 13th day in vitro.Acknowledgment. We thank Dr Latzkovits for useful advice and helping in methodology.     

Oscillations in the rate of disappearance of labeled triiodothyronine from human plasma and the minimum sampling rate for their observation

Conclusions Oscillations in the rate of disappearance of labeled-T3 have been observed in this experiment. A 4-h sampling period is insufficient to demonstrate this behavior; and sampling every 2 h appears to be an approximate upper limit on the sampling period. A more detailed knowledge of the character of these oscillations may be obtained by sampling more often than every 2 h during time intervals when the variations are largest. Curve A in Figure 2 suggests that sampling every hour during the mid-day would be desirable.The results about T3 reported here are not necessarily incompatible with reports that thyroxine (T4) concentration may not be diurnal, as discussed in the introduction. Although T3 and T4 are almost the same species, to within a single atom, their dynamics of distribution, binding and metabolism are sufficiently different 6 for one to be observedly diurnal and the other not. Another possibility is that diurnal variations may exist in T4 disappearance which arc too small to measure by currently available techniques.

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Résumé Des oscillations dans la réduction du taux de triiodothyronine (marquée¹²⁵I) ont été observées dans le plasma humain. On a trouvé qu'une période d'échantillonage de 4 h était insuffisante pour révéler ces oscillations. Une période de 2 h constituerait une limite supérieure adéquate.

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Reparto Medicina Nucleare, 11° Clinica Medica, Università di Roma (Italia).