Promotion of epithelial keratinization by N-methyl-N′-nitro-N-nitrosoguanidine in rat forestomach in organ culture

Summary The effect of N-methyl-N-nitro-N-nitrosoguanidine (MNNG) on epithelial differentiation of fetal rat forestomach was investigated in organ culture. When forestomach tissues removed from 16.5-day fetuses were treated with 5 g and 3 g of MNNG per ml for 1 h, epithelial keratinization was observed after 4 and 5 days, respectively, whereas it occurred after 6 days in control cultures. A clear dose-response relationship was found in the promotion of epithelial keratinization by MNNG.This work was supported by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture, Japan.Acknowledgment. The authors wish to express their gratitude to Prof. T. Mizuno of the University of Tokyo for valuable suggestions.     

Relevance of specific activity in experimental erythrocytocide by 55Fe.

Iron loads between 0.20 microgram and 26 microgram, added to 5 mu Ci 59Fe, 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.     

Epithelial-mesenchymal interaction in differentiation of duodenal epithelium of fetal rats in organ culture

Summary Epithelial-mesenchymal interaction in the differentiation of duodenal epithelium of fetal rats was investigated by recombination experiments in vitro. The proportion of goblet cells in duodenal epithelium was significantly greater on recombination of developing duodenal epithelium with mesenchyme of the glandular stomach than on recombination with that of the duodenum. Mesenchyme of the glandular stomach or forestomach was better than duodenal mesenchyme in supporting morphogenesis of duodenal epithelium. Treatment of tissues with N-methyl-N-nitro-N-nitrosoguanidine (MNNG) did not affect these tissue interactions.This work was supported by grants-in-aid for cancer research from the Ministry of Education, Science and Culture, Japan.Acknowledgment. The authors wish to express their gratitude to Prof. T. Mizuno of the University of Tokyo for valuable suggestions.     

Effects of serotonin and ketanserin on the functional morphology of chick down feather bulbi in vitro.

Chick feather bulbi cultured in vitro showed an increased DNA synthesis and a delayed keratinization after treatment with ketanserin, a serotonin2 antagonist with wound-healing properties. In contrast, serotonin stimulates keratinization of the keratinocytes in the bulbus.     

Effects of serotonin and ketanserin on the functional morphology of chick down feather bulbi in vitro

Summary Chick feather bulbi cultured in vitro showed an increased DNA synthesis and a delayed keratinization after treatment with ketanserin, a serotonin₂ antagonist with wound-healing properties. In contrast, serotonin stimulates keratinization of the keratinocytes in the bulbus.     

Alpha-fetoprotein in tumor-bearing mice assayed by particle agglutination inhibition.

Serum alpha-fetoprotein (AFP) in hepatoma BW7756-bearing mice was measured by a new particle agglutination inhibition test employing AFP adsorbed to charcoal particles. The AFP levels and tumor weights showed nearly parallel increases to means of 2633 microgram/ml and 5.2 g, respectively, 28 days after implantation.     

5-hydroxytryptamine induced changes in body temperature of newborn kittens and guinea-pigs and the effect of indomethacin thereon

During the first days of life 10 microgram i.c.v. 5-HT evoked a primary, short-lasting hyperthermia in kittens and hypothermia in guinea-pigs. In both species, a secondary late hyperthermia occurred that could be prevented by indomethacin pretreatment.     

Luteolytic action of LHRH in women]

Several subcutaneous administrations of 250 microgram of LHRH (4 or 5 adminstrations at 4-hourly intervals per day) between the 2nd and 7th day post-ovulation in 4 normal women led to early luteolysis as demonstrated by a fall in serum progesterone concentration and early onset (2 to 3 days earlier) of menstruation.     

Development of adenocarcinomas after transplantation of rat glandular stomachs treated in vitro with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)

Cellular and Molecular Life Sciences - Glandular stomachs of fetal and newborn Wistar rats were transplanted s.c. after treatment in vitro with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) at...     

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

Effects of alpha- or beta-D-glucose on the respiration of germinated spores (only germinated spores not including swollen spores and elongated spores) of Bacillus subtilis and B. megaterium were studied. In our conditions, net amount of oxygen consumed by 10(10) germinated spores of B. subtilis per min after addition of alpha- or beta-D-glucose was 1.6 microgram or 6.6 microgram (beta/alpha = 4.13), while that by B.megaterium was 4.5 microgram of 6.8 microgram (beta/alpha = 1.51), respectively. However, the net amounts of oxygen consumed by 10(10) vegetative cells per min after addition of alpha- or beta-D-glucose were identical, for B.subtillis in both cases 443.0 microgram and for B.megaterium in both cases 604.4 microgram.     

Reduction of isoprenaline induced tachycardia in pregnant rats. Role of a serum factor]

The in vivo isoprenaline (50 microgram/kg) induced tachycardia (beta 1 adrenergic stimulant effect) was decreased in pregnant (20th day) Rats compared to non pregnant Rats. The in vitro positive chronotropic effect of isoprenaline (10 ng/ml) on cultured Rat heart cells was abolished by pregnant Rat serum whereas progesterone (0.10 to 5 microgram/ml) or oestradiol (0.1 to 25 microgram/ml) were ineffective. The decreased beta 1 adrenergic responsiveness in pregnant Rats could be related to a seric factor, different from these two hormones.     

Metabolism of N-methyl-N'-nitro-N-nitrosoguanidine in rats

Zusammenfassung Versuche mit¹⁴C-markiertem Carcinogen MNNG ergaben an Ratten nach einmaliger Verabreichung der Substanz eine vorwiegend über die Niere erfolgende Elimination. Die Metabolite von MNNG in Verknüpfung mit verschiedenen Stoffwechselstufen und ihre Verteilung im Gewebe wurden näher verfolgt.     

Oxygen consumption of the rat small intestine during infection with nematospiroides dubius

Summary Qo₂ of jejunal rings did not differ significantly between uninfected rats and rats infected for 7 days withNematospiroides dubius. Qo₂ of isolated jejunal mucosal epithelial cells was significantly greater 7 days after infection than in uninfected controls or at 29–36 days after infection.     

Effect of the type of diet on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in rat small intestine

Summary The jejunoileal gradient for the HMG-CoA reductase activity in the microsomal fraction of the epithelial cells of the small intestine of rats given commercial pellets was reserved within a few days after changing the ration to a semipurified diet. The response of the reductase was essentially the same in villus and crypt cells.     

Insomnia induced by P-chlorophenylalanine in cats. Its reversibility by intraventricular injections of indolamines

Intraventricular injection of 250 microgram of 5 HTP induces both slow wave and paradoxical sleep, after 20-60 min. latencies, in insomniac Cats pretreated with P-chlorophenylalanine. Direct injections of 5 HTP in several brain stem structures do not induce sleep. The long latency or paradoxical sleep induction and its suppression with chloramphenicol suggest that indolamines are not directly responsible for paradoxical sleep, but that they act by controlling the synthesis and/or the liberation in the periventricular system of some specific paradoxical sleep inducing factor.     

Apoptotic cell death in the lactating mammary gland is enhanced by a folding variant of α-lactalbumin

Apoptosis is essential to eliminate secretory epithelial cells during the involution of the mammary gland. The environmental regulation of this process is however, poorly understood. This study tested the effect of HAMLET (human -lactalbumin made lethal to tumor cells) on mammary cells. Plastic pellets containing HAMLET were implanted into the fourth inguinal mammary gland of lactating mice for 3 days. Exposure of mammary tissue to HAMLET resulted in morphological changes typical for apoptosis and in a stimulation of caspase-3 activity in alveolar epithelial cells near the HAMLET pellets but not more distant to the pellet or in contralateral glands. The effect was specific for HAMLET and no effects were observed when mammary glands were exposed to native a-lactalbumin or fatty acid alone. HAMLET also induced cell death in vitro in a mouse mammary epithelial cell line. The results suggest that HAMLET can mediate apoptotic cell death in mammary gland tissue.Received 30 January 2004; received after revision 5 March 2004; accepted 16 March 2004     

Effects of lesions of the anterior raphe nuclei on the self-administration of d-amphetamine in the rat : considerable increase of desire for the poison

The acquisition of the intravenous self-administration of d-amphetamine was studied after separate lesions of anterior raphe nuclei (dorsal or median). Every lever-press delivered 2.5 microliter of a d-amphetamine solution dosed at 7.5 microgram/kg. Lesion of anterior raphe nuclei produced an hyper-sensitivity to d-amphetamine as indicated by a dramatic increase in self-administration by experimental Rats compared to the controls. Moreover this enhanced self-administration behavior is observed with a low blood concentration of d-amphetamine. The greater increase was obtained for median raphe lesioned Rats. These effects are interpreted in terms of 5HT-DA balance and could provide an experimental model for neurobiological bases of drug addiction studies.     

The timing of cyclophosphamide therapy in tumor-bearing rats affects the resistance to tumor challenge in survivors

Summary Cyclophosphamide given to rats 2 or 5 days after an injection of Yoshida ascites sarcoma cured approximately the same proportion of animals, but the resistance to a subsequent tumor challenge was found only in rats treated with the drug 5 days after tumor injection.     

Action of cadmium on a free dinoflagellate Prorocentrum micans E: growth, cadmium absorption and cell modifications]

The study of the growth of Prorocentrum micans E. submitted to sublethal doses of cadmium demonstrated a high sensitivity of this Dinoflagellate to the polluant starting with concentration of 5 microgram/l. The uptake of cadmium was measured by pulse polarographic analysis of the filtered culture medium. Structural modifications, not apparent in living cells, are visible after fixation. The high sensitivity of Prorocentrum micans to cadmium, also its easy culture, makes it a suitable pollution indicator of this heavy metal.     

Changes in molecular species of pepsinogens in the development of the chick.

The potential peptic activity of the chick forestomach increases rapidly at the time of hatching. Together with this, the electrophoretic pattern of the pepsinogens shifts to the adult type. These changes take place even under the complete starvation of a newly hatch chick.