Cerebellar decussation of fibres from the nucleus reticularis tegmenti pontis in the brain of the albino rat

Summary The existence of a cerebellar decussation of fibres from the medial portion of each nucleus reticularis tegmenti pontis (Rtp) of the albino rat is indicated. Definite cell loss in the medial aspect, of the most rostral third of Rtp is detectable after cerebellar hemisection involving parts or the entire depth of sublobule VIb. Cell loss in the medial aspect of the caudal half of Rtp is evident as a consequence of experimental lesions which damage both sublobules IIb and III.This work was supported by the Medical Research Council of New Zealand.Acknowledgments. A. special acknowledgment to. Mrs Heather Reid for her excellent preparation of the histological specimens. Grateful thanks to Mrs Maureen Owen for her careful typing assistance.     

Demonstration of the presence of M-creatine kinase in mammalian myogenic cell lines

Summary Unequivocal identification of M-CK in cell extracts from fused cells of myogenic cell lines is difficult due to almost identical behaviour of the M-CK and a contaminating enzyme activity in electrophoresis. If CK dimers present in cell extracts were subjected to dissociation and reassociation in the presence of exogenous B-CK subunits, the formation of easily identifiable MB-CK was demonstrated, indicating the presence of M-CK in the myogenic rat cell lines.Acknowledgments. We are grateful to Mrs M. Siegrist and Dr D. Turner for communication of preliminary results and helpful discussions, Mrs E.R. Perriard for skillful technical help. Supported by a grant of the Muscular Dystrophy Association Inc. to H.M.E.     

Participation of microtubules and microfilaments in the transcellular biliary secretion of immunoglobulin A in primary cultures of rat hepatocytes

Summary The biliary secretion of immunoglobulin A (IgA) in primary hepatocyte cultures was investigated by means of immunofluorescence. The characteristic accumulation of IgA in visible bile canaliculi was found to be strongly inhibited by vinblastine and colchicine or by cytochalasin B, but its surface binding was not.The author thanks Prof. Dr D. Mecke for his support and encouragement. The excellent technical assistance of Mrs M. Behringer and Mrs A. Schneck is gratefully acknowledged. The author is grateful to the BIOTEST Serum Institut (Frankfurt) for the kind gift of human IgA. This work was supported by the Deutsche Forschungsgemeinschaft.     

Effect of acetylsalicylic acid on iron absorption in the rat

Summary The in vivo administration of⁵⁹Fe to the rat accompanied by acetylsalicylic acid (ASA) enhanced significantly counts in blood, spleen, liver and femur without affecting those of the intestine. The results suggest that ASA augments iron absorption either via an inhibitory action on the synthesis of prostaglandins or by a purely chemical mechanism.This work was supported by Grant No. 6638 from CONICET (Argentina).The technical assistance of Mrs María E. Castro and Mrs Patricia Dubra is gratefully acknowledged.     

The size distribution ofTetrahymena in relation to its position in the cell cycle

Summary Tetrahymena size distribution during the cell cycle was analyzed by means of radioautography with the aid of a sonic-digitizer, and a computer. The study demonstrates that as the organism ages and passes through the various cell cycle phases the volume distribution of the organisms in each phase remains lognormal.Acknowledgments. This work was supported by a research grant from Gtiftung Volkswagenwerk No. 112273 toA. Ron. The authors wish to acknowledge the technical help of Mrs.O. Horovitz and MissS. Urieli, as well as the expert photomicrography of Mrs.E. Salomon.     

Autophagy in mouse hepatocytes induced by lysine acetylsalicylate

Summary I.v. administration of lysine acetylsalicylate inces autophagy in mouse liver cells. Single and multiple membrane-bounded vacuoles were found. The latter seems to be an unusual morphological form of the sequestration process. These findings could express a transitory sublethal liver cell injury induced by the drug.Acknowledgments. The authors are indebted to Mrs M. T. Correia and to Mrs M. E. Pereira for technical assistance.     

Anti-myosin stains chromaffin cells

Summary The presence in fixed chromaffin cells of antigenic sites for a myosin antibody was demonstrated using immunofluorescence techniques. Tests on viable cells showed that at least some of the antigenic sites seem to be localized on or close to the cell surface and explained the cell agglutination that occurred with the addition of the myosin antibody to cells isolated by a method described in this paper.Acknowledgments. This work was supported by grants from the Medical Research Council of Canada. We thank Dr B. G. Livett for advice in the preparation of isolated cells, Drs J. Lowenthal and B. Collier for comments and Mrs J. Ritchie for technical assistance.     

Sexual dimorphism of mouse fetal brain lesions after X-irradiation prior to gonadal differentiation

Summary Fractionated X-irradiation of gestational days 11–13 in the mouse, with doses between 3×1.05 and 3×1.33 Gy resulted in rosette-like clusters of primitive ependym-resembling cells dispersed within the cortex walls. Quantification of these abnormalities showed a general prevalence in the female fetuses, especially due to the larger number of rosettes in the females than in the males. It was concluded that X-irradiation acts on sex-specific differentiation steps, which are fully developed at the beginning of the fetal period. At is was recently speculated that these are linked to an early divergence of gene expression between the sexes, we suggest that X-chromosome damage may be involved in the pathogenesis of the dimorphic lesion pattern. While, in principle, this will be valid for any fetal tissue, it only becames evident in the forebrain because of the outstanding relationship between cell necrosis and rosette development in this specific organ.We are greatly indebted for the technical assistance of Mrs E. Senft, Mrs I. Hempfling and Mrs K. Pfaff.     

The number of parallel fibre-Purkinje dendrite synapses. A morphometric evaluation

Summary Quantitative parameters concerning synapses were studied in the cerebellar molecular layer of 4 cats using ultrastructural morphometric methods. The number of parallel fibre-Purkinje dendrite synapses was estimated to be about 200,000.This study was granted by I.N.I.C. (Centro de Morfologia Experimental—MbP₁ e Centro de Anatomia Patológica e Oncologia-MbP₃).The authors thank Mrs M.L. Brito, Mrs M.A. Nascimento, Mrs M.G. Rodrigues and Mr L.B. Nunes for their technical assistance.     

Determination of adhesive rate constant in normal and neoplastic homogeneic cells

Summary The adhesive rate constant (ARC) of neoplastic SGS-2 cells which have a low contact inhibition, is remarkably higher than that of normal homogeneic fibroblasts. This is in contrast with the mutual adhesion theory which states that the loss of contact inhibition is strictly related to the loss of cell recognition and consequently to the loss of cell adhesion capacity.This research was supported in part by the Italian CNR Rome, grant No. 79.00955.04 and in part by the Swiss National Science Foundation, Berne, grant No. 3.499.079. The skilful technical assistance of Mrs Mirjam Valluchi is gratefully acknowledged.     

Contribution to the primary tissue culture technique. A new method for mechanical cell dispersion

Summary A new technique for preparing primary tissue cultures by mechanical cell dispersion was idealized. The time required to prepare a culture by this procedure was greatly reduced and the cultures obtained are morphologically and physiologically of better quality than that obtained by the classical methods of enzymatic cell dispersion.This work was supported by the Conselho Nacional de Pesquisas, Fundo Especial de Despesas do Instituto Butantan and DivisãoNacional do Cancer. The authors wish to thank Mrs.Sibylle Heller for the translation.     

Solubilization of human red cell membranes by lysolecithins of various chain lengths

Summary Red cells and membranes prepared from them were treated with graded amounts of palmitoyl, myristoyl and lauroyl lysolecithins. There was no release of phospholipids from the intact red cells in the absence of hemolysis. The solubilization pattern of lipid and protein from the red cell membranes by lysolecithins varies with their chain length.The skillful technical assistance of Mrs Isca Levy is gratefully acknowledged.     

Adrenalectomy,ovarian HCG-binding and the onset of female puberty in the rat

Summary The delay of puberty onset in female rats adrenalectomized before the 25th day of age is due neither to changes in the number of ovarian HCG-receptors nor to an altered hormone affinity of these receptors. It is assumed that glucocorticoids act on an intracellular level, in the ovarian cells, possibly by alterations of cyclic AMP-dependent phosphodiesterase activity.This work was supported in part by the Deutsche Forschungsgemeinschaft (SFB 46). Purified HCG was a gift of Schering AG, Berlin-West. We thank Mrs Margarete Lindig for assistance and Mrs Ursula Frigewski for secretarial help.     

Reappearance of HCG-receptors in immature rat ovary after HCG-treatment is not due to receptor synthesis

Summary In 24-day-old rats the reappearance of ovarian HCG-receptors after the injection of 200 IU HCG is independent of protein synthesis. The reutilization of occupied receptors in immature female rats is due to dissociation of the receptor-hormone complex.This work was supported in part by the Deutsche Forschungsgemeinschaft (SFB 46). Purified HCG was a gift of Schering AG, Berlin West. We thank Mrs Margarete Lindig and Mrs Rita Rudolph for assistance and Mr A. Schlegel for radioimmunological determinations.     

Inhibition of an early stage of erythropoiesis in cultures of young chick blastodisc cells byRicinus communis agglutinin 120

Summary An early pre-erythroid phase of erythropoiesis in cultures of dispersed cell suspensions prepared from primitive streak and head-fold chick blastodiscs was very sensitive to inhibition byRicinus communis agglutinin 120.This work was supported by grants from the Medical Research Council and National Research Council of Canada. We thank Mrs S. Dorey and N.N. McGrath for technical assistance. S.D.W. is an Associate of the Medical Research Council.     

Binding of fluoresceinated lectins to normal and dinitrofluorobenzene treated human leucocytes

Summary Using fluoresceinated lectins we have shown the receptor distribution on normal human granulocytes and lymphocytes following tagging with 1-fluoro- 2, 4-dinitrobenzene (DNFB). DNP-tagged cells exhibited strong, smooth membrane staining and produced smaller patches dispersed uniformly over the entire cell surface.This work was supported by Grant CA 16503 from the National Cancer Institute.Acknowledgment. We thank Miss C. Pickett for technical help and Mrs E. Olson and N. Shear for secretarial assistance.     

Baroreceptor and sympathetic responses to acebutolol,a 646-1646-1646-1agent,in rabbits

Summary Baroreceptor activity was increased after i.v. infusion of acebutolol in rabbits with an intact circulation, and in rabbits with a total cardiopulmonary by-pass. In rabbits with an intact circulation, renal nerve activity was reduced.We wish to thank Mrs H. Bodard and Mrs F. Raimbault for their technical collaboration and Specia Laboratories for supplying acebutolol. This work was supported by a grant from INSERM (ATP No. 15.75.38).     

Determination of uric acid and hematin in a single sample of excreta from blood-fed insects

Summary Uric acid and hematin, the principle excretory products in blood-fed mosquitoes can be determined quantitatively in the presence of each other in fecal material from individual females.The investigation was supported by a research grant from the Swiss National Science Foundation. The assistance of Mrs E. Csibi and Mrs U. Briegel is gratefully, acknowledged.     

Relation between stimulus intensity and neutrophil chemotactic response

Summary The effect of chemotactic peptides which lack chemokinetic activity has been investigated. The neutrophil response is proportional to the logarithm of the stimulus intensity, or alternatively a power function with an exponent of 0.3. Equal responses are obtained for equal ratios between the peptide concentration in the lower compartment and the threshold concentration. The significance of Weber-Fechner's law in leucocyte chemotaxis is discussed.We thank Miss B. Zanolari, Mrs M. Marti, Mrs Hauck and Mr Dietz for excellent technical assistance. This work was supported by the Swiss National Foundation for Scientific Research.     

Suramin stimulates renal growth in the rat

Summary Suramin given to rats in a single high dose (20 mg/100 g i.v.) stimulated renal growth. Maximum changes are taking place after 6–9 days of treatment.Suramin (Bayer 205) was generously provided by bayer (Leverkusen, Federal Republic of Germany).The authors thank Miss J. Telegdy and Mrs I. Harmos for technical assistance and Mrs M. Herczeg for the preparation of the sections.