The chick oviduct in tissue culture. I. Initial characterization of growing primary oviduct tissue cultures

A simple three-enzyme treatment of collagenase, dispase and hyaluronidase on finely minced chick oviduct yields clumps of 50-150 cells. These cells attach to collagen-treated dishes and survive in culture for at least 2 weeks without subculturing. Oviduct cell cultures can also be induced to grow. Estradiol or epidermal growth factor (EGF) induce a 40% increase in cells in 4 days when cultures are grown in serum levels that do not support growth. Serum from estrogen-stimulated chicks promotes rapid cellular proliferation (doubling times of 1-2 days). Sera from estrogen withdrawn chicks, laying hen or horse do not support as rapid proliferation. The oviduct growth-promoting factors in serum from estrogen-stimulated chicks are not steroids or fibroblast growth factors (FGF). Removal of steroids from these sera by charcoal treatment or delipidization does not decrease the rate of growth. The addition of 1-100 nM estradiol does not increase a serum's ability to promote growth. Purified FGF or platelet-derived growth factor (PDGF) do not induce oviduct proliferation. These results were reproduced in oviduct cell cultures started from estrogen-stimulated and withdrawn chicks as well as laying hens. Thus the factors in serum from estrogen-stimulated chicks that promote rapid oviduct growth are induced by estrogen treatments in vivo, but do not seem to be only steroids.     

Modulation of platelet responsiveness through selective phosphorylation of plasma membrane proteins: Antagonistic eeffects of cyclic AMP and cyclic GMP

³²P phosphorylation of plasma membranes from human blood platelets, under conditions that closely resemble physiological ones (endogeneous phosphate donors and intact platelets in homologous plasma), result in the incorporation of the label mainly in a membrane glycoprotein of apparently high molecular weight (greater than 400 000). Dibutyryl cyclic AMP, an inhibitor of platelet aggregation, specifically increases the degree of phosphorylation of this glycoprotein. Moreover, it has been found that prostaglandin E₁ one of the most potent inhibitors of platelet aggregation which also increases phosphorylation of the same glycoprotein, is significantly more effective than cyclic AMP.Cyclic GMP does not have any apparent effect on platelet aggregation. However, incubation of platelet-rich plasma with both cyclic GMP and cyclic AMP results in a partial recovery of the platelet responsiveness towards ADP-induced aggregation. Coincidently, the degree of phosphorylation of the high molecular weight glycoprotein under these conditions, although still higher than in controls (no nucleotides added), is significantly decreased as compared with cyclic AMP-treated cells. Furthermore, cyclic GMP inhibits the cyclic AMP-dependent protein kinase activity in isolated platelet plasma membranes.These results suggest a central role for this membrane phosphoglycoprotein in the triggering of platelet aggregation and, furthermore, suggest that modulation of its degree of phosphorylation may be exerted through some cyclic AMP/cyclic GMP relationship, which in the basal state might be critical for platelet responsiveness.     

Yeast invertase: Subcellular distribution and possible relationship between the isoenzymes

The intracellular invertase ofSaccharomyces cerevisiae is mainly found in a soluble form (91–95%), while only minor amounts are found bound to the internal (4–8%) and plasma membranes (less than 1%). In the processes of derepression or repression, inhibition of RNA or protein synthesis, or in the presence of 2-deoxy-d-glucose, the levels of the membrane-bound and external activities are modified in a way in which their relation is clear, while the soluble enzyme does not change at all. These results, together with the fact that the membrane-bound and the external enzymes are glycoproteins, suggest a precursor-product relationship between the enzymic forms.     

Measurement of bone displacement in a macerated human skull induced by orthodontic forces; A holographic study

A macerated human skull was subjected to orthodontic forces from 6.25 to 7.0 N per side. Double-exposure holographic interferograms (5 mW HeNe laser) were made frontally and oblique laterally. These were complemented with observations from a real time holographic interferogram. The displacements of the maxilla and the zygomatic bone were quantified. Special attention was paid to the reaction of the zygomaticomaxillary suture.     

Mutants of Saccharomyces cerevisiae cell division cycle defective in cytokinesis. Biosynthesis of the cell wall and morphology

The four temperature-sensitive mutants of Saccharomyces cerevisiae in the cell division cycle defective in cytokinesis (cdc, 3, 10, 11 and 12), have been analyzed with respect to the biosynthesis of the cell wall polymers. After 3 hours of incubation at the non-permissive temperature (37°C) these strains stop growing. The synthesis of glucan, mannan and chitin (wall polymers) level off in a similar time, but glucan, mannan and chitin synthases remained active for at least 4 hours.If the mutants are analyzed by transmission and scanning electron microscopy different pictures emerge. Two of the mutants cdc 10 and cdc 12, after 3 hours of incubation at 37°C present apparently normal cytoplasms and cell wall surfaces with multiple elongated buds. The other two mutants, cdc 3 and cdc 11, present a completely disarranged cytoplasmic content and damage at the level of the plasma membrane is evident.These and other observations, suggest that between the execution points of cdc 3 (0.27) and cdc 10 (0.58), essential processes in the assembly of cell membrane occur.This work was supported in part by a grant from la Comisión de Investigación Científica y Técnica of the Spanish Ministerio de Educación y Ciencia (Project no. 4593-1980).     

An A alpha Ser-434 to N-glycosylated Asn substitution in a dysfibrinogen, fibrinogen Caracas II, characterized by impaired fibrin gel formation.

We have identified a unique N-glycosylated Asn substitution for a Ser at position 434 of the A alpha chain of an abnormal fibrinogen designated fibrinogen Caracas II. This dysfibrinogen was characterized by impaired fibrin monomer aggregation. Since there were 4 Thr residues immediately following the mutation, a new Asn-X-Thr/Ser-type consensus sequence, Asn-Thr-Thr arose for N-glycosylation of the Asn. The extra oligosaccharide was found to consist mainly of a disialylated biantennary structure comprising 81.9%, while a neutral and a monosialylated biantennary oligosaccharide represented only 3.6% and 14.5%, respectively. The mutation resides in the carboxyl-terminal region of the A alpha chain, which could fold back to form an extra small globular region located near the central region of the molecule (Erickson, H.P., and Fowler, W.E. (1983) Ann. N. Y. Acad. Sci. 408, 146-163; Weisel, H.P., Stauffacher, C.V., Bullitt, E., and Cohen, C. (1985) Science 230, 3124-3133). Therefore, the participation of this region, referred to as an additional central domain or an alpha domain, in fibrin gel formation is strongly implicated.     

Interstitial stem cell proliferation in hydra: evidence for strain-specific regulatory signals.

We have examined the growth behavior of small numbers of interstitial stem cells transplanted into tissue of genetically unrelated strains of Hydra magnipapillata. We show that such stem cells, which are at low density following transplantation, proliferate more rapidly than the stem cells of the host, which are at normal density. The rapid proliferation is similar to the proliferation rate of stem cells transplanted into interstitial cell free tissue. The results suggest that stem cells transplanted into heterotypic tissue are unable to "sense" the presence of host stem cells and to adopt their growth rate to that of the surrounding cells. Thus, the feedback signal which negatively regulates stem cell growth as a function of stem cell density must be strain specific.     

The influence of ionic composition on the distribution of nematode species in springs of the province of Granada (Spain)

The ionic composition of 38 mineral springs in the province of Granada (Spain), and the distribution of 45 species of nematodes belonging to orders Monhysterida, Araeolaimida, Chromadorida and Enoplida were examined. Water chemistry is used to make two diagrams representing anionic and cationic composition. Diagrams for anionic composition (given the greater variance seen in the springs considered) are used to illustrate the distribution of individual species. The results obtained from species distribution and the correlation between species made it possible to group species which could be associated with springs where each of the anions considered predominated. A greater number of species groups was found to inhabit springs in which chloride concentrations was less than 50% of the total concentration of anions.     

The relationship of mechanical properties to morphology in patellar tendon autografts after posterior cruciate ligament replacement in sheep.

In a sheep model the posterior cruciate ligament (PCL) was replaced by a patellar tendon autograft (PTAG) using the central one-third of the ipsilateral patellar tendon (PT). The sheep were sacrificed at 16, 26, 52 and 104 weeks postoperation. The PTAG, and, as controls, the contralateral PCL and PT were harvested. These were examined using biomechanical testing as well as light and transmission electron microscopy, including immunohistological techniques. The material properties (maximum stress, elastic modulus) were compared to the morphological features. The cellular distribution, the distribution of glycosaminoglycans (GAGs), the collagen fibril diameter and the occurrence of Type III collagen were studied. Prior to transplantation, the PTAG was shown to be superior in maximum stress (57.2 +/- 5.5 MPa vs 41.3 +/- 1.9 MPa) and elastic modulus (368.8 +/- 49.3 MPa vs 172.3 +/- 14.6 MPa) to the PCL. The early decline in material properties of the PTAG (maximum stress 22% and elastic modulus 42% of the control) after free grafting paralleled a cell- and capillary-rich PTAG tissue with remnants of necrosis and a poorly organized extracellular matrix. Two years after implantation, with progressive alignment of the tissue matrix, maximum stress and elastic modulus acquired approximately 60 and 70% of the control, respectively. However, there was also an evidence of degenerative changes characterized by acellular areas, loss of the normal bundling pattern of collagen fibers and abnormal accumulation of GAGs. Ultrastructurally, there was a predominant shift to thin collagen fibrils in the PTAG compared to PCL and PT, both consisting of thick and thin collagen fibrils. Thin fibrils were demonstrated to be, in part, split thick fibrils as well as newly formed fibrils. Most of these thin fibrils revealed a positive reaction with antibodies to Type III collagen.