Stimulation of calcitonin secretion in the fasting newborn rat by ingestion of triglycerides]

The stomach gavage of fat (triglycerides) in the fasting newborn Rat induced a marked increase in the plasma concentration of immunoreactive calcitonin after 30 and 60 mn. Calcium chloride given by the same route at the dose of 20 mg calcium per kg body weight had a poor effect on calcitonin secretion. This stimulation was probably mediated through some gastro-intestinal hormone that has to be uncovered.     

Induction of anti-Treponema pallidum antibodies in normal rabbits by RNA-immuno-carrier extracted from serum of syphilitic rabbits

Zusammenfassung Es wird bestätigt, dass die i.v. Injektion von RNA aus dem Serum Syphilis-infizierter Kaninchen in gesunde Kaninchen die Bildung der Abwehrstoffe gegenT. pallidum verursacht.     

Ultrastructural changes in the dorsal root ganglia evoked by thalidomide in rabbits

Summary Administration of the teratogenic drug thalidomide to pregnant does produces ultrastructural changes in foetal ganglion cells, Schwann cells and axons in the posterior root ganglia corresponding to forelimb segments deformed by the drug. Ultrasttructural changes in ganglia appear on the 13th day of gestation, i.e., preceding the appearance of limb malformation.This work was supported by a grant from Foundation 41.We are grateful to MissC. Ellis and Mr.P. Westphal for technical assistance.     

Absorption and translocation of tetrachlorodibenzo-p-dioxine by plants from polluted soil

Summary Measurements were made of contamination of plants grown in soil polluted with tetrachlorodibenzo-p-dioxine. Findings show that the pollutant is absorbed and translocated by the plants studied and suggest that the pollutant may be eliminated in the course of time.Acknowledgment. This research was sponsored by the Regional Government of Lombardy, Italy. The authors would like to thank Prof. Marrè for his continuous interest and for the fruitful discussion.     

Ultrastructural changes in the dorsal root ganglia evoked by thalidomide in rabbits.

Administration of the teratogenic drug thalidomide to pregnant does produces ultrastructural changes in foetal ganglion cells, Schwann cells and axons in the posterior root ganglia corresponding to forelimb segments deformed by the orug. Ultrastructural changes in ganglia appear on the 13th day of gestation, i.e., preceding the appearance of limb malformation.     

Effect of prolactin on fluid and NaCl absorption by the rat proximal and distal colon

Summary The rates of fluid and NaCl absorption are greater in the proximal than in the distal colon. Prolactin treatment caused significant increases in fluid and NaCl absorption in the proximal but not in the distal colon. This suggests that only the proximal colon region, where most of the fluid and sodium absorption takes place, is responsive to prolactin.This work was supported by N.I.H grant Ca-05388 and a Rockefeller Foundation Fellowship.The author is greatly indebted to Professor H.A. Bern for his advice and useful suggestions.     

Reactivation of yeast glucose-6-phosphate dehydrogenase denaturated by saturated fatty acids

Summary Activity of yeast glucose-6-phosphate dehydrogenase, inactivated by treatment with saturated fatty acids, can be partially restored by incubation in a medium of suitable ionic composition. The effectiveness of ions in the reactivation process is inversely related to their chaotropic properties. Time-dependence of reactivation extent suggests a 2-step mechanism of enzyme inactivation and the existence of an intermediate form that aggregates through a 2nd-order reaction, producing irreversibly inactive enzyme.This work was supported by a grant of the Italian Consiglio Nazionale delle Ricerche.     

Reduction of efferent renal nerve activity by propranolol in rabbits]

During intravenous infusion of propranolol (0.3--0.8 mg/kg) in the Rabbit, systolic arterial pressure is decreased (-6.5 +/- 4.2 mmHg) and electrical activity recorded from central end of the renal nerve is reduced significantly (-8.7 +/- 14.-%) with regard to the activity obtained, at the same pressure levels, by hemorrhage (+7.9 +/- 6.4%; p less than 0.25) or by intravenous infusion of the peripheral vasodilator sodium nitroprusside (+14.1 +/- 9.9%; p less than 0.01).     

Induction of hyperlipidemia by human thyroid stimulating hormone immunization in rabbits

Summary In our study we are able to demonstrate that with TSH booster and bleeding animals 10–20 days post immunization, when rabbits have increased in antibody titer, there is an increase in cholesterol and triglyceride. These findings are suggestive that most probably we are rendering these rabbits hypothyroid.Acknowledgments. The authors are indebted to Miss J. Meister for her skillful technical help. We are also indebted to the National Institute of Arthritis, Metabolism, and Digestive Diseases for Human Thyroid Stimulating Hormone for iodination.     

Platelet aggregation and stimulation of leucocyte procoagulant activity by rickettsial lipopolysaccharides in rabbits and in man

Summary The effects in vitro of 4 purified lipopolysaccharide (LPS) preparations from Rickettsiae on platelets and leucocytes were studied in rabbits and in man. All LPS induced aggregation in rabbit platelet-rich plasma but to differing degrees. This activity was abolished by inactivation of complement. None of the preparations induced aggregation of human platelets. Both rabbit and human leucocytes, when incubated with each of the rickettsial LPS preparations, generated a potent procoagulant activity (tissue factor). These findings add further support to the concept that rickettsial LPS behave as typical LPS from gram-negative bacteria and may be relevant to the understanding of the mechanism(s) responsible for triggering intravascular coagulation in rickettsial diseases.