Oncogenic transformation by fractionated doses of neutrons

Oncogenic transformation was assayed after C3H 10T1/2 cells were irradiated with monoenergetic neutrons; cells were exposed to 0.23-, 0.35-, 0.45-, 5.9-, and 13.7-MeV neutrons given singly or in five equal fractions over 8 h. At the biologically effective neutron energy of 0.45 MeV, enhancement of transformation was evident with some small fractionated doses (below 1 Gy). When transformation was examined as a function of neutron energy at 0.5 Gy, enhancement was seen for cells exposed to three of the five energies (0.35, 0.45, and 5.9 MeV). Enhancement was greatest for cells irradiated with 5.9-MeV neutrons. Of the neutron energies examined, 5.9-MeV neutrons had the lowest dose-averaged lineal energy and linear energy transfer. This suggests that enhancement of transformation by fractionated low doses of neutrons may be radiation-quality dependent.     

The kinetics of the first wave of spermatogenesis in the newborn male mouse

A combination of autoradiography and air-dried techniques was used to calculate the duration of the major meiotic stages in the first wave of spermatogenesis in the newborn mouse. The data indicated that the entry into meiosis occurred asynchronously over 2 days, and the time required for each stage and the total cycle was constant. These time intervals were nearly identical with those estimated for adult animals in the present study and by other authors.     

Placental-soluble aconitase polymorphism in Japanese

Polymorphism of soluble aconitase was investigated in 152 Japanese placentae. The allelic frequencies were ACONS1 = 0.951 and ACONS2 = 0.049. ACONS2 appears to be rather high among Orientals including Japanese, while ACONS4 seems to be characteristic for Negroids.     

Immigration of the brown planthopper, Nilaparvata lugens, exhibiting various responses to density in relation to wing morphism

Considerable inherent variations in the relation between macropterous and brachypterous wing forms, and nymphal density were found in field populations of the brown planthopper, Nilaparvata lugens Stål (Homoptera: Delphacidae), collected from various locations in Japan. When compared under uniform laboratory rearing conditions, most of the female populations exhibited higher ratios of macropters with increasing nymphal density, but some showed extremely high proportion of brachypters and the others were highly macropterous, over broad ranges of density. These results indicate the possibility that the planthoppers in Japan, which are known not to persist in winter, are derived from different migration sources.About ten generations of successive selection for brachyptery from a population showing usual density-dependent wing morphism generated populations similar to highly brachypterous ones mentioned above. Genetic analysis of the inheritance of wing morphism revealed that brachyptery in the females was controlled by a single pair of dominant alleles. However, in the males wing forms did not segregate so clearly in the crossing experiments. This suggests that wing morphism in N. lugens in under sex-limited inheritance.

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Einwanderung von Nilaparvata lugens mit unterscheidlicher Reaktion auf Populationsdischte bei der Flügelausbildung

Zusammenfassung In Feldpopulationen von Nilaparvata lugens Stål., welche in verschiedenen Regionen Japans gesammelt wurden, bestand in der Beziehung zwischen makropteren bzw. brachypteren Flügelformen und der Larvendichte eine beträchtliche Variation. Unter einheitlichen Zuchtbedingungen im Laboratorium stieg der Makropterenanteil bei den meisten Weibchenpopulationen mit steigender Temperatur; bei einigen Populationen hingegen war entweder der Brachypterenanteil oder der Makropterenanteil extrem hoch und zwar über weite Dichtebereiche. Dies deutet auf die Möglichkeit hin, dass die Zikade in Japan, wo sie bekanntlich nicht überwintert, jeweils aus verschiedenen Quellen einwandert.Wenn eine Population mit der üblichen dichteabhängigen Flügelausbildung 10 Generationen lang auf Brachypterie selektioniert wurde, entstanden Populationen, die den erwähnten hochbrachypteren Populationen aus dem Feld glichen. Die genetische Analyse der Vererbung der Brachypterie ergab, dass bei Weibchen ein einzelnes dominantes Allel verantwortlich ist. Bei Männchen dagegen trennten sich bei Kreuzungsexperimenten die Flügelformen nicht so klar. Dies deuted auf Unterschiede zwischen den Geschlechtern bei der Vererbung der Flügelformen.

     

Mutation in Pseudomonas aeruginosa causing simultaneous defects in penicillin-binding protein 5 and in enzyme activities of penicillin release and D-alanine carboxypeptidase.

Penicillin-binding protein 5 in Pseudomonas aeruginosa had moderately penicillin-sensitive D-alanine carboxypeptidase activity. As in Escherichia coli, a defect in this enzyme activity was not lethal.     

Combined effects of gamma rays, cis-diamminedichloroplatinum (CDDP) and systemic hyperthermia mastocytoma transplanted into muscle in the mouse

Comparison was made between the effects of local irradiation of gamma rays, s. c. injection of cis-diamminedichloroplatinum (II) (CDDP), systemic hyperthermia and their combinations on the i. m. transplanted murine mastocytoma. Increase of the mean survival time (M. S. T.) by a factor of 1.72 and of 1.68 was achieved by a single irradiation at 20 Gy, given on day 5 after transplantation, and by injections of CDDP at 2 mg/kg, given s. c. on days 5 and 12 after transplantation, respectively. Increase of M. S. T. by a factor of 1.10 which was achieved with systemic hyperthermia of 41.8 degrees C of the core body temperature for 5 min, given twice, on days 5 and 12 after transplantation, was not statistically significant. The most effective one among all possible combinations within the 3 modalities was that of radiation and CDDP. Increase of M. S. T. was by a factor of 4.01.     

Muscarinic acetylcholine receptors in rat gastric mucosa

Summary The muscarinic cholinergic innervation of the rat gastric mucosa was investigated by localizing the muscarinic receptors using a tritiated muscarinic antagonist, pirenzepine. Radioautography was performed by freeze drying stomach tissue, which was then embedded in Epon and wet sectioned with ethylene glycol, and dry mounting on emulsion film by the wire-loop method to prevent loss of the labelled substance during fixation and the radioautographic procedure. Light and electron microscopy showed that the specific pirenzepine-binding sites were localized predominantly on parietal cells, chief cells and perivascular plexuses. Analysis of the grain distribution on parietal cells revealed that the silver grains corresponding to the pirenzepine-binding sites were mainly on the basolateral plasma membrane. On the other hand, the surface mucous or mucous neck cells had few pirenzepine-binding sites.     

Level of translatable messenger RNA coding for argininosuccinate synthetase in the liver of the patients with quantitative-type citrullinemia

Summary The translation activity of mRNA coding for argininosuccinate synthetase in total RNA extracted from the liver of three patients with quantitative-type citrullinemia was determined using a cell-free translation system. In two patients, the hepatic content of the enzyme was about 20% of the control value, whereas translatable mRNA level for the enzyme was similar to or slightly lower than those of control livers. In the third patient, the enzyme content was about 50% of the control value, and mRNA activity for the enzyme was low normal. These results indicate that at least in the first two patients, the decrease in the enzyme protein is due either to increased degradation of the enzyme or to decreased translation in the patient's liver.     

Sensitivity of mice to systemic hyperthermia: effect of the transplantation of ascites tumor cells modified by preheating, and by an injection of CDDP or interferon

Effects of preheating and injection of cis-DDP (CDDP) or interferon on tumor-induced sensitization to systemic hyperthermia (SH) was investigated in mice. LD50 of SH at 42.0 +/- 0.2 degrees C (core body temperature) was 43 min in normal mice and 8 min in mice which were i.p. transplanted with FMA3 cells at a dose of 10(5) one day before. In mice which had received the SH for 10 min one hour before, one hour after or one day before the transplantation, LD50 of the SH one day after the transplantation was 41, 35 and 22 min, respectively. An injection of CDDP given i.p. at a dose of 4 mg/kg one day after the transplantation, which was effective to kill about 99% of the tumor cells, did not change the course of thermosensitization after the transplantation. An i.p. injection of mouse interferon did not change the thermosensitivity of normal mice, but greatly suppressed the thermosensitizing effect of tumor cells when it was given one day before the transplantation.     

Isolation of virus causing hemorrhagic fever with renal syndrome (HFRS) through a cell culture system

Twenty-three rat lung specimens collected in outbreaks of hemorrhagic fever with renal syndrome (HFRS) in three medical institutions were inoculated onto the VERO-E6 cell monolayers. After several blind passages, an agent growing serially in the cell cultures and reacting specifically with known HFRS-positive sera was isolated from two of these specimens. The two isolates were antigenically identical each other. The agent, named strain SR-11, was identified as the causative virus of HFRS by its antigenic identity with E6 cell-adapted HFRS virus, Hantaan 76-118 strain, and the specific reactions with sera from various HFRS cases.