Repercussions de l'hyperthyroïdie sur le contenu total en ADN du cervelet de rat âgé de 6 et 35 jours. Effets comparés de la LT3 et de la DLT4

Summary The total cerebellar proteins RNA and DNA contents from DLT4- and LT3-treated rats was studied at 6 and 35 days of age. The effect of injections of 5 g/j of DLT4 is comparable to that of 25 g of LT3 at birth, followed by 0.5 g every 2 days. On the other hand, injection of 0.5 g of LT3 every 2 days does not induce any significant modification of the total DNA contents in the cerebellum.     

Giant pigment granules in dermal melanocytes of rat scrotal skin

Summary Giant melanosomes, ellipsoidal (1.5 m×1.3 m) or spherica (1.1 m–1.4 m in diameter) exist in the scrotal skin of the black pelted Long Evans rat. They are longer and wider than normal stage IV melanosomes (0.7 ×0.4 m) found in theses dermal melanocytes.The authors acknowledge with gratitude, the technical assistance of Evelyn Ann Flynn. This work was supported by grant AM 20669-16 from the National Institute of Arthritis, Metabolism, and Digestive Diseases, USPHS.     

Defensive steroids from a carrion beetle (Silpha americana)

Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15-hydroxyprogesterone (1, principal component), 5-pregnan-15-ol-3, 20-dione (2), 5-pregnan-3, 15-diol-20-one (3), 5-pregnan-7, 15-diol-3,20-dione (4), 5-pregnan-3, 7, 15-triol-20-one (5), 5-pregnan-16-ol-3,20-dione (6), and 5-pregnan-3, 16-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 g level.Paper No. 78 of the series: Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908, AI-12020). We thank Maura Malarcher and Maria Eisner for excellent technical help, and the Squibb Institute of Medical Research for samples of authentic reference compounds.     

Chromosomes and some issues of the evolution of the ground squirrel genusCitellus (Rodentia: Sciuridae)

Citellus (s. str.) relictus, C. dauricus C. pygmaeus (2=36, NF=72). . (Colobotis) erythrogenys . fulvus -. . (Urocitellus) undulatus (2n=32, NF=64) . columbianus. Citellus, , Citellus, . , .     

Dopamine and cerebral cortical blood flow in the rat

Summary Dopamine topically applied to the cerebral cortex (1–20 g/ml) or administered i.v. (0.5–64 g/kg/min) has no effects on cerebral cortical blood flow in the rat.     

Melatonin decreases the amplitude of the b-wave of the human electroretinogram

In a double-blind placebo crossover study of 13 healthy volunteers, the pineal hormone melatonin (10 mg) was given at 4 pm, and the electroretinogram measured under conditions of dark and light adaptation. A significant diminution of b-wave amplitude was found under both photopic (=5.4 V, p<0.05) and scotopic conditions (=7.4 V, p<0.01). These data indicate that melatonin may transduce the dark signal at the level of the retina as well as the pineal. Acute administration of melatonin decreases sensitivity to light.     

Antidiuretic effects of oxytocin in the Brattleboro rat

Summary The antidiuretic activity of oxytocin (OT) was measured in Brattleboro rats with congenital diabetes insipidus. A dose dependent antidiuretic response was found in animals receiving chronic infusions of 0.1 g/h, 1.0 g/h, and 5 g/h of OT. OT infused at the rate of 5 g/h over a 7-day period completely reversed the symptoms of diabetes insipidus. The results support the concept that OT serves as a weak agonist of vasopressin at the level of the kidney and at pharmacological levels exhibits antidiuretic activity.     

The levels of metallothionein-like proteins in animal tissues

Summary The level of metallothionein-like proteins was determined in different tissues of 6 animal species. The highest concentrations were found in pig and rat tissues. The organs richest in metallothionein-like proteins included: kidneys (101–305 g/g), intestine (127–257 g/g) and liver (54–496 g/g).Studies performed under the Polish-American agreement 05-009-2 with National Institute for Occupational Safety and Health, PHS, USA.     

Uptake of D-glucose anomers by rat retina

Summary Uptake ofd-glucose anomers by isolated rat retina was studied. After 3 min incubation at 37°C in the presence of or anomer (750 g/ml), a significantly greater uptake (1.32 mg/g wet tissue) of -anomer was observed compared with that of -d-glucose (1.11 mg/g wet tissue). This result and other data suggest that the carrier ford-glucose transport in the retina prefers the -anomer stereospecifically.Acknowledgment. The authors are grateful to Mr S. Suzuki for his technical assistance.     

Failure of somatostatin to influence experimental tumor cell growth in vivo and in vitro

Summary The influence of somatostatin on tumor cell growth was studied in vivo in mice (sarcoma 180 ascites tumor and Lewis lung tumor) and in vitro on nontransformed and polyoma-transformed cell lines. 4 or 20 g/100 g of cyclic somatostatin and 4 g/100 g of linear protamin Zn-bound somatostatin were injected s.c. twice daily in the in vivo study. Cyclic somatostatin (1, 4 or 10 g/ml) was added twice daily to the cell cultures. Somatostatin administration influenced neither the survival of animals nor the growth rate of cultured cell lines. *** DIRECT SUPPORT *** A2025117 00011     

Il punto nella terminologia matematica greca

Summary In this note we claim that the two words and , which were used in Greece to indicate the geometrical point, had both been introduced in the scientific language in the first half of the IV^th century B.C., and that they became popular independently of each other in two different cultural circles, those of philosophy and of mathematics, respectively.We propose therefore, in contrast to a conjecture by Heiberg, a new explanation for the predominance of during the golden age of Greek mathematics and for the resurgence of during the period of decadence.

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Memoria presentata da A. Seidenberg     

Different effects of D-glucose anomers for respiration of bacterial germinated spores

Summary Effects of - or -D-glucose on the respiration of germinated spores (only germinated spores not including swollen spores and elongated spores) ofBacillus subtilis andB. megaterium were studied. In our conditions, net amount of oxygen consumed by 10¹⁰ germinated spores ofB. subtilis per min after addition of - or -D-glucose was 1.6 g or 6.6 g (/=4.13), while that byB. megaterium was 4.5 g or 6.8 g (/=1.51), respectively. However, the net amounts of oxygen consumed by 10¹⁰ vegetative cells per min after addition of - or -D-glucose were identical, forB. subtilis in both cases 443.0 g and forB. megaterium in both cases 604.4 g.     

Inhibitory effect of fasting on the glucagon-induced increase of liver phosphorylase A activity in rats

Summary The increase of liver phosphorylase A activity observed 1, 2 and 3 min after i.v. administration of 0.1 g kg^–1 glucagon to fed rats was found to be completely absent in 24 h fasted animals, although there is even an exaggerated liver cAMP response to glucagon after fasting.Acknowledgments. We would like to thank Mrs M. Fritzová and Mr F. Kovai for expert technical assistance.     

Phenytoin-induced DNA synthesis and inositol 1,4,5-triphosphate formation in L-929 fibroblasts

Summary Culture of L-929 fibroblasts in the presence of phenytoin (2.5–5.0 g/ml) increased DNA synthesis, as indicated by increased [³H]thymidine uptake, while a higher dose (20 g/ml) inhibited DNA synthesis. In like manner, a low dose of phenytoin (5.0 g/ml) was effective in increasing inositol 1,4,5-trisphosphate formation while a higher dose (10 g/ml) tended to inhibit this activity. These data suggest that the formation of inositol phosphate second messengers may play a role in phenytoin-induced fibroblast proliferation and connective tissue growth.     

Central nicotinic receptor blockade inhibits emotionally conditioned pressor responses in rats

A conditioned stimulus previously paired with electric footshock produced an increase in blood pressure in conscious, freely moving rats. The conditioned pressor response was reproducible. Intracerebroventricular injection of the nicotinic receptor antagonists hexamethonium (1–10 g) or pentolinium (10 g) but not the muscarinic receptor antagonist methylatropine (3 g) produced an inhibition of the conditioned pressor response, whereas intraarterial injection of hexamethonium (10 g) did not affect the response. Intraventricular injection of the cholinesterase inhibitor physostigmine (3–10 g) produced an enhancement of the conditioned pressor response. These results are consistent with the possibility that central nicotinic receptors play a role in the expression of the emotionally conditioned pressor response in rats.     

Storage of irradiated human blood; a source of error in quantitative chromosome analysis

Summary Human whole blood was irradiated with 2.5 Gy of 220 kVp X-rays and stored before culture with 9.7 M BrdU and 19.4 or 38.7 M BrdU for 0, 24, 48 and 72 h. The frequency of dicentrics and ring chromosomes was determined in cells staining as first division (M1) metaphases with the fluorescence plus Giemsa technique. Storage had no influence on the observed aberration yields in 44 h cultures containing 9.7 M BrdU. In 66 h cultures at 19.4 M BrdU the observed yields after 2 and 3 days' storage were significantly lower as compared to cultures from fresh blood. No storage effect was revealed in 66 h cultures containing 38.7 M BrdU. In cases where cytogenetic radiation dosimetry has to be carried out using blood samples which have been in transit for 2–3 days, the findings are of relevance for a correct determination of the chromosome damage in M1 cells.     

Relevance of specific activity in experimental erythrocytocide by55Fe

Summary Iron loads between 0.20 g and 26 g, added to 5Ci⁵⁹Fe, were followed for up to 150 days in mice. Relative organ uptake increased as a function of iron load in liver and kidneys while it decreased in bone marrow and blood. Several weeks after injection, all load-related differences disappeared.Research carried out under the auspices of the US Department of Energy and by NIH GRANT HL-15685-02.     

Induced seed protein mutant of barley

. 51%. () 29% 9% - . .

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Seed samples may be obtained upon application toH. Doll.     

A study of the mechanism of polymyxin M inactivation

.I.NH₄OH , N N - - ,-. , .