Muscle atrophy following section of the spinal cord in the rat

Zusammenfassung Nach Myelotomie verläuft die Muskelatrophie in zwei Phasen. In der ersten Phase stimmt der Gewichtsverlust der Muskeln mit demjenigen nach Denervation überein. Dagegen erfolgt in der zweiten eine Gewichtszunahme, die durch die analoge Gesamtzunahme des Körper-gewichts erklärt wird.     

Polyamines and nucleic acids in rat liver subjected to ionizing radiation

Riassunto Un considerevole aumento di spermina e spermidina è stato osservato nel fegato di ratti dopo 48 h dalla pan-irradiazione con dosi totali di raggi X di 800 e di 1000 r. Gli acidi ribonucleici si modificano nello stesso modo, quantunque in misura minore.     

Effects of ionizing radiation on myelinogenesis in the chicken

Résumé Chez le poulet, l'irradiation (1600 R rayons gamma) retarde la croissance de l'organisme in toto et de plusieurs organes, et affecte sélectivement les constituants individuels de la myéline plutôt que le processus global de myélinisation, l'accumulation de la sphingomyéline étant plus retardée que celle de la cérébroside et du cholestérol.     

Influence of ionizing radiation on protein production by HeLa cells in culture

Zusammenfassung Bei der Züchtung von HeLa-Krebszellen in tritiumhaltiger Nährlösung während 48 h wurde festgestellt, dass die Mitoserate durch viel kleinere Strahlendosen nachweisbar herabgesetzt wird als die radiochemisch gemessene Rate der Proteinsynthese.     

Neuronal cell deficits following maternal exposure to methadone in rats

Summary Rat offspring were maternally subjected to methadone hydrochloride during gestation or lactation. At 21 days of age, the area of the pyramis (cerebellar lobule VIII) in prenatally and postnatally exposed groups was reduced 45% and 36%, respectively, from control levels, and the total number of internal granule neurons/section was reduced 49% and 46%, respectively; the number of granule neurons/mm² in both groups was 75% of control values. Based on histological evaluation the timetable of cerebellar morphogenesis was unaltered in rats prenatally exposed to methadone, suggesting a permanent neuronal deficit, but cerebellar development was markedly delayed in animals subjected postnatally.This work was supported by National Institute on Drug Abuse grant DA-01618.     

Pattern of cell damage due to ionizing radiation in the epithelial lining of the intestine inHeteropneustes fossilis bloch

Zusammenfassung Der Vorgang der Strahlenschädigung wurde an der Epithelzellschicht des Darmes des SüsswasserfischesHeteropneustes fossilis untersucht. Schon 2 h nach der Strahleneinwirkung ist eine Veränderung der Zellform und des Zellkerns zu erkennen. Die Zellen an den Spitzen der Fasern werden als erste in das Lumen ausgepresst. Becherzellen sind besonders strahlenanfällig und verschwinden schon nach kurzer Zeit. Die Neubildung beginnt vom 2. Tag an, und Becherzellen sind vom 4. Tag an wieder zu beobachten.     

Lipofuscin accumulation in squirrel monkey spinal cord consequent to protein malnutrition during gestation

Summary The formation of lipofuscin pigment in the anterior horn cells of the cervical spinal cord has shown in the fetuses and neonates under the extrinsic influence of maternal protein deprivation during the gestation period in the squirrel monkeys.Acknowledgments. This work was supported by US PHS grants RR-00165 HD-06087 from National Institute of Health. The technical assistance of Miss Judie Seubert is greatly appreciated.     

Differential lethality following treatment with ionizing radiations of various energies in Drosophila

Male and female gametes of Drosophila were treated with various doses of ionizing radiations: X-rays at different energy, and gamma-rays from 2 sources given singly and in 2 temporal sequences. The induced lethality was assessed in successive developmental stages by scoring the number of eggs, larvae and adults. The results clearly show that the effects of various radiations appear in terms of difference among developmental stages and/or between treated sexes/genotypes. It is suggested that the various energies affect different gene functions which are not completely independent, as supported by the non-additive effects of the two temporal sequences.     

Increase in the survival time of mice exposed to ionizing radiation by a new class of free radical scavengers

Summary N-acyl dehydroalanines react with and scavenge mainly superoxide radical and hydroxyl radical (HO^.). The ortho-methoxyphenylacetyl dehydroalanine derivative, indexed as AD-20, protects mice against damage resulting from total body X-irradiation, as measured by the increase in their survival time. AD-20 increases the LD₅₀ at 30 days from 6.1 to 7.3 Gy in animals exposed to a wide range of X-rays (6 to 10 Gy). The dose reduction factor (D R F) of AD-20 is 1.20. We postulate that such radioprotective effect may result from its free radical scavenging activity.     

Increase in the survival time of mice exposed to ionizing radiation by a new class of free radical scavengers

N-acyl dehydroalanines react with and scavenge mainly superoxide radical (O-2.) and hydroxyl radical (HO.). The ortho-methoxyphenylacetyl dehydroalanine derivative, indexed as AD-20, protects mice against damage resulting from total body X-irradiation, as measured by the increase in their survival time. AD-20 increases the LD50 at 30 days from 6.1 to 7.3 Gy in animals exposed to a wide range of X-rays (6 to 10 Gy). The dose reduction factor (D R F) of AD-20 is 1.20. We postulate that such radioprotective effect may result from its free radical scavenging activity.     

Response of respiration to selective heating of the spinal cord below partial transection

Conclusions The experiments indicate that the signals arising from thermal stimulation of the spinal cord are conducted to higher spinal and to supraspinal thermoregulatory effector systems by afferent fibers which run in the ventrolateral, but not in the dorsal portions of the spinal ascending tracts. This corresponds to the observation ofWünnenberg andBrück that shivering induced by external cooling is not inhibited by heating the lower cervical and upper thoracic spinal cord, if the ventral funiculi are transected at a higher cervical level. -These findings are parallel to the observation that the inhibitory effect on shivering of skin pressure is no longer present after contralateral transection of the ventrolateral funiculus at a higher level, i. e. after transection of the so-called ventral spinothalamic tract. Likewise, it has been observed that modifications of electrocortical activity following thermal stimulation of the skin or following changes of environmental temperature are abolished, if the ventrolateral funiculi are transected at the cervical level. -It may be suggested, therefore, that the afferent signals arising from spinal thermosensitive structures might follow the same ascending pathway as do the discharges of peripheral thermodetectors.

---

Zusammenfassung Der Einfluss thermischer Reizung des Rückenmarks unterhalb einer Teildurchschneidung in Höhe von Th 4–Th 11 auf Atmung, Hautdurchblutung und motorische Aktivität wurde an leicht narkotisierten Kaninchen untersucht. Mittels Marchi-Färbung einige Tage nach Durchschneidung wurden die ausgeschalteten afferenten Bahnen ermittelt. Nach Durchschneidung der Hinterstränge und anschliessender Abschnitte der Seitenstränge konnte durch Rückenmarkwärmung unterhalb der Durchschneidung eine thermische Tachypnoe und eine Hautvasodilatation oberhalb der Durchschneidung ausgelöst werden. Diese Reaktion war nach Durchschneidung der Vorderseitenstränge erloschen.