Immunofluorescence identification of cells with corticotropic and alpha-melanotropic activity in the hypophysis of the grass snake Natrix natrix L.]

The use of anti ACTH (17-39) and alpha-MSH allowed us to detect by immunofluorescence in the Pituitary gland of Grass Snake the site of elaboration of ACTH and alpha-MSH. Corticotropic cells are located in the rostral part of the Pars Distalis and in the Pars intermedia. Melanotropic cells occupy the whole part of the Pars intermedia.     

Effects of 6-hydroxydopamine on rat carotid body chief cells

Summary Administration of 6-hydroxydopamine (6-OHDA) in concentrations high enough to cause degeneration of perivascular adrenergic nerve terminals has no morphological effect on the catecholamine-storing cells of the rat carotid body. Uptake of 6-OHDA by carotid body chief cells may be more selective than that exhibited by small-intenselyfluorescent cells and other catecholamine-storing cells which are affected by 6-OHDA. Alternatively, the sustentacular cells which envelope the chief cells may provide an effective barrier against the uptake of 6-OHDA.Supported by a Grant-in-Aid from the American Heart Association (77 630) and with funds contributed in part by the Texas Affiliate.     

Immunocytochemistry of pituitary corticotroph cells in terrestrial turtle (Testudo mauritanica)]

The immunocytochemical and histochemical characters of the corticotroph cells of the Turtle adenohypophysis have been studied. These cells are localised in the rostral part of the gland and are revealed by Is anti ACTH (1-24) and (17-39). They are also colored with lead hematoxyline and PAS-Orange G. The corticotroph nature of these cells is confirmed by the study of their modifications after treatment with amphenone and ACTH. The Is anti ACTH also reveal most of the cells of the pars intermedia; while the Is anti beta-MSH reveals only these cells and some scatter cells of the pars distalis.     

Depletion of cellular glycogen during the early logarithmic growth phase of human fibroblasts

Summary Human diploid fibroblasts deplete 50% of their cellular glycogen by day 4 after subcultivation in 100 mg% glucose medium. The glycogen content increases again as the cells approach confluency. Growth of cells in low glucose medium results in rapid glycogen depletion and indicates that stored glycogen has a limited potential as an energy source.Supported in part by a grant from the Frank G. Bressler Fund.     

New histochemical contributions to the study of corticotropic cells in the adenohypophysis of the chick enbryo.]

Comparative analysis of results obtained after subsequent treatments of chick embryo adenohypophysis by anti-ACTH 17-39 Is, PAS and Bodian method demonstrates that ACTH cells are PAS positive, Bodian negative and are located in the cephalic lobe. With the histochemical fluorescence method of Falck, the cells marked by anti-ACTH 17-39 Is exhibit an induced fluorescence, after L-DOPA injection. However, after treatment by metopirone, numerous cells of the caudal part of the adenohypophysis take up L-DOPA but they are not corticotrophs.     

Facilitation of synaptic transmission by diazepam in a perfused frog cerebellum

Summary The action of diazepam on the parallel fibres-Purkinje cell synapse was studied in a perfused frog cerebellum. Diazepam facilitates the excitatory input to Purkinje cells and hence increases the inhibition produced by Purkinje cells activity.Supported by a grant from the Israel Center of Psychobiology.This work is part of M. D. Thesis by Y. B. N.     

Glycine-rich proteins as structural components of plant cell walls

Glycine-rich proteins (GRPs) have been found in the cell walls of many higher plants and form a third group of structural protein components of the wall in addition to extensins and proline-rich proteins. The primary sequences of GRPs contain more than 60% glycine. GRPs are localized mainly in the vascular tissue of the plant, and their coding genes provide an excellent system to analyze the molecular basis of vascular-specific gene expression. In French bean, the major cell wall GRP has been localized at the ultrastructural level in the modified primary cell wall of protoxylem. Immunological studies showed that it forms a major part of these highly extensible and specialized cell walls. Specific digestion of GRP1.8 from bean by collagenase suggests that it shares structural similarities with collagen. The protein is synthesized by living protoxylem cells as well as xylem parenchyma cells. After cell death, GRPs are exported from neighboring xylem parenchyma cells to the protoxylem wall, a rare example of protein transport between cells in plants. We propose that GRPs are part of a repair system of the plant during the stretching phase of protoxylem.     

Immunohistochemical demonstration of the loss of immunoreactive amylase from neoplastic human salivary gland

Summary Antihuman parotid amylase antibodies raised in rabbits and horses were used as the primary antibodies in both the peroxidase-antiperoxidase and sandwich techniques for the localization of human amylase. Immunoreactive enzyme was demonstrated in the normal acinar cells of salivary glands and pancreas. Malignant transformation, which has occasionally resulted in ectopic production of amylase by various tissues, actually caused a loss of amylase synthesis by the transformed acinar cells of salivary glands and did not result in elaboration of amylase by transformed ductal cells.Acknowledgment. This is publication No. 80-27 and was supported in part by National Institutes of Health research grant GM-19178.     

Effect of carbon particles on the recovery of bone marrow stem cells after irradiation in LPS-resistant C3H/HeJ mice

Summary Effect of RES-blockade on bone marrow cells was studied serially after irradiation in LPS-resistant mice. Injection of carbon particles reduced damage and accelerated recovery of marrow hemopoietic stem cells, indicating that LPS-resistant mice can react normally to RES-blockade.This work was supported in part by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture, Japan.     

Differential displacement of cells from the median eminence into the arcuate nucleus during puberty. Effects of melatonin administration

A displacement of catecholaminergic-positive and catalase-containing cells from the median eminence into the arcuate nucleus at puberty has been described previously. This study reports on the displacement phenomena after postnatal administration of melatonin. Catalase-positive cells undergo a delayed displacement from the median eminence into the arcuate nucleus. However, part of this cell population lags behind within the median eminence. This differential reaction of cell displacement by catalase-positive cells is considered as a special reaction of these cells to melatonin administration.     

Ultrastructural observation on the tips of growing vascular cords in the rat cerebral cortex

Summary The distal ends of the vascular cord in the cerebral cortex are investigated electron microscopically in rats at the 13th postnatal day. The tip of the vascular cord consists of central cuboidal cells (primitive endothelial cells) and surrounding flat cells (primitive pericytes), and has no lumen. The primitive endothelial cells (tip cells) possess several long tentacles which contain only fibrous structures and extend through the neuropile.This study was supported in part by a grant in aid for Scientific Research from the Ministry of Education of Japan (No. 448085).     

Immigration of lymphoid precursor cells into the thymic rudiment inXenopus

Summary The origin of thymic lymphocytes was investigated, using a new reliable method to mark cells inXenopus. It was easily observed that extraneous cells immigrated into the thymic rudiment 4 days after fertilization and differentiated into a cell population identified as thymic lymphocytes in a fully developed thymus. Clearly, lymphoid precursor cells are of extrinsic origin.This work was supported in part by a grant from the Ministry of Education, Science and culture of Japan (No. 59770026).     

Alterations in bone-marrow cellularity following thymectomy in rats

Summary The number of nucleated marrow cells was decreased following neonatal thymectomy in rats, and was corrected by administration of syngeneic lymphoid cells, or by implantation of a syngeneic testis. These results suggest that, in the rat, as has been shown previously in the mouse, lymphoid cells exert parital control over bone marrow cellularity and this effect may be further modulated by sex steroids.Supported in part by NSF-RIAS 77-06922, NIH AM21137 and the Morseman Foundation.     

Neuronal activity specific to paradoxical sleep in the bulbar reticular formation in the unrestrained cat]

Single units were recorded in the bulbar reticular formation (BRF) of unrestrained, freely behaving Cats. In the ventromedial part of the BRF (n. reticularis magnocellularis, Mc) corresponding to the "bulbar inhibitory center", we have found a cluster of cells showing tonic activation highly selective to paradoxical sleep (PS). Furthermore, we have confirmed the presence of the same type of cells in the dorsomedial part of the BRF which corresponds to the medial part of the n. reticularis parvocellularis (Pc). The functional significance of these two groups of cells is discussed in terms of the postural atonia and the atonia of jaw closer muscles observed during PS.     

Differential displacement of cells from the median eminence into the arcuate nucleus during puberty. Effects of melatonin administration

Summary A displacement of catecholaminergic-positive and catalase-containing cells from the median eminence into the arcuate nucleus at puberty has been described previously. This study reports on the displacement phenomena after postnatal administration of melatonin. Catalase-positive cells undergo a delayed displacement from the median eminence into the arcuate nucleus. However, part of this cell population lags behind within the median eminence. This differential reaction of cell displacement by catalase-positive cells is considered as a special reaction of these cells to melatonin administration.     

Structure of gap junctions in cultures of normal and neoplastic bladder epithelial cells

Summary Normal rat urinary bladder epithelial cells contain small subunit (PF-1) and large subunit (PF-2) gap junctions, whereas carcinoma cells only contain PF-1 gap junctions. The absence of PF-2 gap junctions, which are composed of larger connexons with slightly larger ionic channels, may contribute to altered metabolic coupling between urinary bladder carcinoma cells.Acknowledgments. The authors wish to thank Ms Denise Wiler and Mr William Leonard for expert technical assistance. This work was supported by funds from the National Cancer Institute, CA-25034, and in part by the Otho SA Sprague Memorial Institute.     

A reticulum of nerve-like cells from trochophores of Phyllodoce mucosa (Polychaeta)

Summary The positions of and connections between the 12 principal cells of the larval reticulum are described from Golgi-Cox preparations and sections.Supported by the National Research Council of Canada and carried out in part at the Huntsman Marine Laboratory, St. Andrews, N.B.     

Effect of infection of mice with Friend leukemia complex viruses on background antibody-forming cell production in vitro

Summary Friend leukemia complex (FLC) and Rowson-Parr virus (RPV) infections of donor mice depress the production of background antibody-forming cells by splenocytes cultured in the absence of specific antigenic stimulation.Supported in part by a grant from the Italian Research Council (Progetto finalizzato virus, CT 77.00248.84).     

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.     

Glycoprotein biosynthesis in splenic cells. Purification of a microsomal galactosyl-transferase.

One part of the microsomal galactosyl-transferase activity of splenic cells of rats can by solubilized by the action of Triton X-100 and Tween 20. Its purification on a Sephadex G-200 column and by electrophoresis on a polyacrylamide gel leads to a solution of high specific enzymic activity.