Mechanism of age-dependent involution in embryonic chick notochords

To study the possible mechanism of the age-dependent involution of the notochord, isolated mesenchymefree notochords of chick embryos were cultured in vitro and compared with their counterparts in vivo. Two different aspects were evaluated: (1) DNA synthesis measured by [³H]thymidine incorporation and visualized by autoradiography and (2) cell death quantified by counting the number of pyknotic nuclei. The results demonstrate that [³H]thymidine uptake by notochords shows an age-dependent decrease in vitro as well as in vivo. The number of [³H]thymidine-labelled notochord cells, however, is higher in vitro than in vivo. At the same time, there is an age-dependent increase in pyknosis in the notochord in vivo and in vitro. So, during the aging process, the number of both pyknotic nuclei and of [³H]thymidine-labelled nuclei suggest a high turnover of notochord cells in vitro. From these results, we can conclude that the process of involution in aging notochord seems to be controlled by a programmed intrinsic process, which might be influenced partially by the microenvironment in vivo.     

Protective effects of vitamin E and dithiothreitol against the hemolysis of rat and goat erythrocytes induced by Tween 20 with or without ascorbic acid and azide

Summary Exrtensive in vitro hemolysis of erythrocytes, induced in vitamie E-deficient rats by 0.001% Tween 20 with ascorbic acid and azide, or in goats by 2.5% Tween 20, could be counteracted by either the inclusion of vitamin E in the cells or by the in vitro addition of 0.25–0.4 mM dithiothreitol.     

Viability of rabbit bone marrow after cryopreservation (in vitro and in vivo)

Summary A technique for preservation of rabbit bone marrow is described, which preserves viability of stem cells in all 22 animals as tested by autologous bone marrow transplantation and in vitro growth. Erythroid precursors survived better than myeloid precursors as observed by in vitro and in vivo recovery.Supported by the Swiss Science Fondation 3.846.0.79.     

Stimulation parameters determine role of GABAB receptors in long-term potentiation

Blockade of GABA_B receptors was reported to improve cognitive performance in mammals. The physiological basis of this effect is poorly understood. We investigated the effect of the GABA_B receptor antagonist CGP 35348 on long-term potentiation (LTP) in the CA1 area of the hippocampus in vitro and in vivo. In vitro the effect of CGP 35348 on LTP, induced either by two non-primed tetanic stimulations or by two primed bursts of stimuli, was investigated. In the presence of 1 mM CGP 35348 LTP was significantly facilitated following two non-primed tetanic trains, but was impaired following two primed burst stimulations. In vivo LTP was induced by applying non-primed trains of stimuli of increasing duration to the Schaffer collateral/commissural fibers. The potentiation of the population spike recorded in CA1 was significantly facilitated by CGP 35348 (100 mg/kg i.v.). In conclusion these findings demonstrate that the GABA_B antagonist CGP 35348 facilitates LTP in vitro and in vivo if induced by non-primed tetanic stimulation. In vitro, the mode of stimulation determines the effect of the GABA_B antagonist on LTP.     

Elimination and metabolism of dimethylnitrosamine (DMN) by Xenopus laevis and other amphibians

The elimination of (14C)-DMN after i.p. injection into Xenopus was measured, as was the metabolism in vitro of (14C)-DMN by liver from Xenopus and 9 other amphibian species. In view of its rapid elimination from the body and low rate of metabolism by Xenopus liver in vitro, DMN is unlikely to be toxic or carcinogenic in Xenopus.     

Transcriptome profiling of lung schistosomula,in vitro cultured schistosomula and adult Schistosoma japonicum

The schistosomulum is the main target of vaccine-induced protective immunity; however, most studies have utilized schistosomula produced by mechanical transformation of infective larvae followed by in vitro culture rather than larvae isolated directly from the lungs of infected mammals. Using transmission electron microscopy, we demonstrated that there was little difference in the ultrastructure of Schistosoma japonicum schistosomula obtained by the two methods. However, significant differences in gene expression profiles were apparent when we used an oligonucleotide microarray to compare the gene expression profiles of schistosomula obtained in vivo from lung tissue with those maintained in vitro, and with adult worms of S. japonicum. It is likely that host environmental factors, which cannot be reliably reproduced in vitro, do influence the growth, development and overall biology of schistosomes. Thus caution is urged when using in vitro-cultured schistosomes and mechanically transformed/cultured schistosomula in molecular, biochemical and immunological studies.     

In vitro biosynthesis of juvenile hormone III by the corpora allata ofCalliphora vomitoria and its role in ovarian maturation and sexual receptivity

Summary JH III is the only JH detected by GLC-MS in medium from in vitro incubations of corpora allata of adult females ofCalliphora vomitoria. When corpora allata were removed from females at various times during the reproductive cycle and the JH III produced by the glands in vitro measured by a JH III radioimmunoassay, an increase in the level of synthesis was found to occur before previtellogenesis (0–24 h). A second increase appeared at the onset of vitellogenesis (72–83 h) and continued until the end of vitellogenesis (96 h) and the occurrence of chorionation (120 h). Since sexual receptivity develops with vitellogenesis, the significantly higher levels of JH III biosynthesis in vitro at this time supports a possible role for JH in the acquisitive of receptivity.     

Mode of action of a soluble restricted factor, a suppressor of the allogeneic proliferative response in man

Appearance of "suppressor cells" is induced by in vitro hyperimmunization of lymphocytes against allogeneic cells, incompatible for one HLA-DR antigen. These "suppressor cells under certain conditions, release in the culture medium, "suppressor factors" of the in vitro allogeneic proliferative response in Man. They are not immunoglobulins and act in a non specific way towards the stimulators. Only one of them is restricted to some individuals. This is shown when either responders or stimulators are incubated for different periods, with the "suppressor factors" prior to the primary mixed lymphocyte reaction (MLRI). The beneficial effect of transfusions on kidney graft survival, could be, in part, explained by a suppressor mechanism, analogous to the one described in vitro.     

Electrical stimulation induces clot retraction after previous in vitro platelet aggregation

Summary the spontaneous clot retraction of platelet-rich plasma is inhibited by previous in vitro ADP-induced platelet aggregation. The electrical stimulation of the clot always restores a maximal clot retraction, even after a prolonged previous in vitro platelet aggregation.Acknowledgment. We thank Mr Renzo Ferronato for his technical assistance and Miss Maria Tommasini for her secretarial aid.     

Evidence for changes in cell shape from a 2-dimensional to a 3-dimensional substrate.

Chick embryo mesoderm cells were explanted to culture systems in vivo and in vitro and their subsequent movements were correlated with the external morphology as studied by SEM. In vitro cell movements are exaggerations of normal in vivo movements where a 2-dimensional substrate is encountered rather than a 3-dimensional environment.     

Ribosomal bodies specific to both pollen and zygotic embryogenesis inDatura

Summary Induction of pollen embryos in vitro or zygotic embryos in situ is characterized by the formation of RNA-rich cytoplasmic bodies. These are observed in all pollen embryos irrespective of the different pathways of androgenesis followed in vitro.We thank Drs brigitte S. Sangwan-Norreel and A. Kovoor for discussions and Mr J. Schaeffer for technical assistance.     

Effect of aminoglutethimide on murine fetal hepatic erythroid colony formation

Pretreatment of pregnant mice with aminoglutethimide phosphate, an inhibitor of glucocorticoid synthesis, increases the content of fetal liver erythroid colony-forming cells (CFU-E), as assessed by the formation of erythroid colonies in vitro by fetal liver cells in plasma clots containing exogenous erythropoietin. In addition, the inability of aminoglutethimide to influence erythroid colony formation in vitro suggests that endogenous glucocorticoids exert a suppressive effect on the number of functional CFU-E in the fetal liver.     

Formation of trypsin inhibitors during alkaline treatment of proteins

Casein is submitted to a severe alkaline treatment (NaOH 0,2 or 0,5 N, 1 hr., 80 degrees C). The hydrolysis by pancreatic enzymes (trypsin or chymotrypsin) is reduced in vitro and, in the case of the more severe treatment, stopped. After an extended (24 hrs.) trypsin and pronase hydrolysis, it is shown, by affinity chromatography, that peptides, which are not hydrolysable, can bind to trypsin and inactivate this enzyme in vitro.     

The islet-acinar axis of the pancreas: Is there a role for glucagon or a glucagon-like peptide?

Intravenous glucagon inhibits exocrine pancreatic secretion in vivo, but exogenous glucagon does not affect exocrine secretion in vitro. Recent work, however, suggested that endogenous glucagon may be involved in the regulation of exocrine secretion even in vitro. We therefore investigated the effects of exogenous and endogenous glucagon on exocrine secretion by the isolated perfused rat pancreas in the presence of 1.8 mM glucose. Exogenous glucagon did not affect CCK-stimulated amylase output. 20 mM arginine stimulated glucagon release, but did not affect basal enzyme secretion. CCK-stimulated amylase output, however, was significantly inhibited in the presence of arginine. This inhibitory effect of arginine on exocrine pancreatic secretion could be blocked by glucagon antibodies, but not by nonspecific gammaglobulins. Thus exogenous glucagon failed to affect exocrine pancreatic secretion in vitro, but endogenously released glucagon or a glucagon-like peptide inhibited amylase release in the isolated perfused pancreas. We conclude that glucagon or a glucagon-like peptide may be a mediator in the islet-acinar axis.     

In vitro neurogenesis: development and functional implications of iPSC technology

Neurogenesis is the developmental process regulating cell proliferation of neural stem cells, determining their differentiation into glial and neuronal cells, and orchestrating their organization into finely regulated functional networks. Can this complex process be recapitulated in vitro using induced pluripotent stem cell (iPSC) technology? Can neurodevelopmental and neurodegenerative diseases be modeled using iPSCs? What is the potential of iPSC technology in neurobiology? What are the recent advances in the field of neurological diseases? Since the applications of iPSCs in neurobiology are based on the capacity to regulate in vitro differentiation of human iPSCs into different neuronal subtypes and glial cells, and the possibility of obtaining iPSC-derived neurons and glial cells is based on and hindered by our poor understanding of human embryonic development, we reviewed current knowledge on in vitro neural differentiation from a developmental and cellular biology perspective. We highlight the importance to further advance our understanding on the mechanisms controlling in vivo neurogenesis in order to efficiently guide neurogenesis in vitro for cell modeling and therapeutical applications of iPSCs technology.     

Vitamin E,catalase, manganous or cobaltous ions and dithiothreitol protect against Tween 20-induced hemolysis of vitamin E-deficient chick and kid erythrocytes

Summary The effective Tween 20 concentration at which 70% hemolysis was achieved in vitro correlated with the plasma vitamin E content of chicks (r=0.85). Addition of catalase, MnCl₂, CoCl₂ or dithiothreitol in vitro showed significant protection against the hemolysis induced by Tween 20 in vitamin E-deficient chick and kid erythrocytes.     

On the in vitro behaviour of mouse submaxillary gland cells. II. Metabolic differences between male and female C3H mice

Summary Submaxillary gland cells from female C3H mice were isolated, cultivated in vitro and their metabolic properties compared with those of male derived cells. From the results it can be concluded that these cells retain their metabolic differences when grown in vitro.This work was supported by grant No. CT 73.00642.04 from the Consiglio Nazionale delle Ricerche (C.N.R.), Roma, Italy.     

Effect of Plasmodium berghei infection on benzoic acid metabolism in mice

The metabolism of benzoic acid was studied in Plasmodium berghei infected mice both in vitro and in vivo. Results of in vitro studies showed a considerable decrease in the ability of the infected liver to detoxify benzoic acid by hippuric acid formation. The in vivo study showed that hippuric acid formation decreases with increasing parasitemia and the emergence of benzoyl-glucuronide. This new pathway stops operating with further increase in parasitemia.     

Determination by three technics of cellular immunology of the antigenic determinants of the Ly-Li system expressed on human B lymphocytes]

A clear correlation has been observed between the presence of the antigenic B cell system Ly-Li detected serologically, and 3 cellular immunology techniques: 1. MLR inhibition by anti-Li serum; 2. level of restimulation of anti-Ly-Li in vitro primed lymphocytes; 3. detection of HLA-D alleles by homozygous typing cells. These results suggest that the allelic products detected serologically may be identical to those detected by the first two techniques, namely MLR inhibition and in vitro primed lymphocyte typing, and possibly HLA-D typing using homozygous typing cells, although the correlation was found to be repeatedly less clear for the last technique.     

Effect ofPlasmodium berghei infection on benzoic acid metabolism in mice

Summary The metabolism of benzoic acid was studied inPlasmodium berghei infected mice both in vitro and in vivo. Results of in vitro studies showed a considerable decrease in the ability of the infected liver to detoxify benzoic acid by hippuric acid formation. The in vivo study showed that hippuric acid formation decreases with increasing parasitemia and the emergence of benzoyl-glucoronide. This new pathway stops operating with further increase in parasitemia.