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Biomedical subjects

R Robineaux

Publications and source records attributed to R Robineaux.

At least 19 recordsLinked to original sources
PubMed1985

Immunocompetent cells in the starfish Asterias rubens. An ultrastructural study.

Cells from the axial organ of the starfish Asterias rubens were fractionated into two populations, adherent and non-adherent to nylon wool. In both populations the ultrastructural study revealed the presence of cells resembling the lymphocytes of the vertebrates, as well as phagocytic, peroxidase positive cells. The lymphocyte-like cells in the non-adherent population (average diameter 4 mu) have a high nucleo-cytoplasmatic ratio and are morphologically similar to Th lymphocytes while the adherent cells (average diameter 5.5 mu) are more similar to Bm lymphocytes. These observations are in line with the hypothesis that there exist, in the starfish, a primitive immune system with characteristics resembling those of the immune system of vertebrates.

Animals↗
PubMed1984

The spatial organization of nucleolar DNA in phytohemagglutinin-stimulated lymphocytes of the guinea pig.

The ultrastructural changes in the spatial organization of nucleolar DNA in lymphocytes during phytohemagglutinin (PHA) stimulation was studied in guinea pigs by means of oxidized diaminobenzidine (DAB) at low pH as a differentially contrasting stain for nucleic acids and by the use of reconstruction of serial sections. The extended DNA filaments situated inside the fibrillar area originate from a large aggregation of heterochromatin, which is closely associated with the nucleolus, and from the perinucleolar shell of condensed chromatin. It is suggested that these two distinct regions of chromatin might be associated with different functions.

Animals↗
PubMed1984

Possible role of sialic acid and endogenous neuraminidase in T-cell proliferation.

The proliferation of T cells in MLR with strains C57Bl/6 and DBA2, mouse spleen and lymph node cells was increased when the inhibitors of endogenous neuraminidase was added in the culture. This is in favor of participation of this enzyme and implicitly of terminal sialic acid in the proliferation of T-cells. Ths possibility that the suppressive activity of T-cells might have been abolished is discussed.

Animals↗
PubMed1983

[Nucleolar lesions induced by ribonuclease in living cultured cells].

The nucleolar lesions provoked by the action of ribonuclease (RNase) on living chick embryo fibroblasts were studied by means of microcinematographic analysis and at the ultrastructural level using oxidized diaminobenzidine as a differentially contrasting stain for nucleic acids. This study has shown that the induction of nucleolar dispersion by RNase was only the beginning of a series of discrete steps. The following sequences are described: dispersion of the nucleolus into fragments, their reassembly, and the emission of spherules which appear of chromatin origin. At that step nucleoli are typically segregated. The alteration of the nucleolar associated chromatin seemed to be primordial in these processes. Moreover, the large mass of heterochromatin intimately associated with the nucleolus and which has been considered to be a part of the nucleolar organizer region apparently plays a chief part in the reassembly of the nucleolar fragments into a segregated nucleolus. Ribonuclease is compared to other drugs known to act on nucleolar DNA.

3,3'-Diaminobenzidine↗
PubMed1982

Destruction of Leishmania mexicana amazonensis amastigotes within macrophages in culture by phenazine methosulfate and other electron carriers.

Exposure of macrophages infected with Leishmania mexicana amazonensis to phenazine methosulfate (PMS) resulted in rapid damage and disappearance of the intracellular amastigotes without obvious ill effects to the host cells. The reduction of the percent infection was related to the concentration of PMS and to the duration of the pulse. Most Leishmania disappeared within 2 h of a 2-h pulse with 10 muM of the drug. In contrast, pretreatment of the macrophages with PMS followed by removal of the drug before infection did not result in disappearance of the parasites. The pH of the PMS medium markedly influenced the disappearance of Leishmania: maximum effect was observed at pH 8.0, while the effect was negligible at pH 6.3. The pH effect may be related to pseudobase formation by the PMS cation. Dose-response curves for PMS were similar for resident, elicited, or activated macrophages. Observations by time-lapse cinemicrography documented the explosion-like fragmentation of the amastigotes within 1-2 h of exposure of infected macrophages to the drug. Parasite-derived granules and vacuoles were seen to scatter within the parasitophorous vacuoles. This early damage to the parasites was confirmed by transmission electron microscopic observations. Infected macrophages incubated with PMS displayed detectable vacuolar fluorescence, indicating that PMS or a metabolite of PMS had access to the vacuoles. A series of other electron carriers, including phenyl methanes, phenazines, oxazines, a xanthene, and a naphthoquinone, given continuously for 18 h, also induced the disappearance of the Leishmania. The most potent was crystal violet, active at 70 nM. The presence of apolar substituents enhanced activity and this is probably related to increased permeation of the dyes. Finally, PMS, as well as other electron carriers examined, also reduced the growth of Leishmania promastigotes in culture. The results are compatible with a direct effect of the drugs on the intracellular amastigotes, involving only a permissive participation of the macrophages. We propose that the diverse agents destroy the amastigotes by redox-cycling generation of active oxygen metabolites at or near the parasites. Alternatively, the effect of the drugs could be mediated by toxic free radical reduction species of the drugs or by interference with electron flow or with the intermediary metabolism of Leishmania.

Animals↗
PubMed1980

3H-glucosamine and 3H-fucose incorporation by murine peritoneal macrophages "non-divided" during differentiation in vitro.

Normal murine peritoneal macrophages were maintained in culture for 24 hours and 6 days. These cells continuously incorporated 3H-glucosamine and 3H-fucose in their membrane components. For both precursors culture ages, these components may be considered to undergo turnover according to a given rhythm with a 24 hours doubling time. Treatment with neuraminidase did not modify the doubling time, although a slight increase of incorporation of radioactivity was observed. Variations of 3H-fucose and 3H-glucosamine incorporations were observed. Variations of 3H-fucose and 3H-glucosamine incorporations were observed between 24 hours old and 6 days old cultures: 6 days old cultures incorporated more glucosamine than 24 hours old cultures whereas no difference in fucose incorporation was observed between the two cultures.

Animals↗
PubMed1978

Hairy cell leukemia: a clinical, immunological and ultrastructural study. New data for the origin of the hairy cell.

Seven patients presenting with the characteristic clinical and laboratory findings of HCL were investigated mainly in order to find the origin of the HC with histochemical, electron microscopic and immunologic techniques. The results we obtained are somewhat contradictory, as in the recent literature, if the HC's are to the considered as being exclusively of lymphocytic or monocytic origin. The data however indicate that HCL is not of one cell type but two. One of these cells has characteristics of a lymphocyte. The other one, an ill defined cell, has mixed characteristics of both the monocyte and lymphocyte series. This hairy cell may represent a new cell line.

Adult↗
PubMed1978

Acute eosinophilic leukemia. An ultrastructural study.

Observations on a 32 year old male are described. Hematological examination demonstrated leukocytosis with circulating blastosis and dystrophic hypereosinophilia of the blood and bone marrow, with cells at various stages of maturation. Cytotoxic chemotherapy led to complete remission for 5 months followed by a terminal relapse. No features in favor of an "eosinophilic collagenosis" were revealed at autopsy. Repetitive ultrastructural studies performed during evolution of the illness demonstrated considerable anomalies of the eosinophil line. The present observation thus shows the clinical, evolutional, cytological and autopsy criteria of an acute eosinophilic leukemia.

Adult↗
PubMed1977

Ultrastructural characteristics of developing eosinophil leukocytes in human bone marrow during acute leukemia: evidence for extracellular granule release from human eosinophils.

Developing eosinophils from the bone marrow of a patient with acute "eosinophilic" leukemia were characterized by electron microscopy. It was suggested that the first sequential step in granule formation occurred at the level of the endoplasmic reticulum without actual participation of the Golgi complex. Progressive densification of the former profiles, presumably mediated by Golgi vesicles, resulted in the formation of dense immature granules. Ultrastructural observations of the "leukemic" eosinophils which were generally arrested at an intermediate stage of maturation revealed also large vacuoles containing sequestered immature granules, without any indication of phagocytic activity. Morphological evidence that has been accumulated indicates that the membrane of these vacuoles fused with the cell membrane, thus being in contact with the extracellular space. These profiles strongly suggested that granules and/or granule-associated material were secreted by developing bone marrow eosinophils.

Acute Disease↗
PubMed1976

Studies on autoimmune encephalomyelitis in the guinea pig. II. An in vitro investigation on the nature, properties, and specificity of the serum-demyelinating factor.

Complement-dependent demyelinating activity of whole brain homogenate (WBH)-induced experimental allergic encephalomyelitis (EAE) sera was tested on long term tissue cultures of in vitro myelinated fetal guinea pig cerebellum. Complement-fixing (CF) auto-antibodies were shown to be the responsible agents, as demonstrated in experiments where all reagents belonged to the same species: guinea pigs of outbred (Hartley) and even of inbred (S2 or S13) strains. These antibodies were of the IgG2 class as shown by Sephadex G-200 and DEAE cellulose fractionation experiments. The corresponding auto-antigen was present in the homogenate and myelin of the central nervous system (CNS) tissue. It was different from the encephalitogenic basic protein of CNS myelin (BP), as shown in experiments where the demyelinating auto-antibodies were induced, detected, and absorbed by WBH or by CNS myelin but not by BP. They were neither induced by nor cross-reacting with cerebroside and peripheral nervous system (PNS) tissue.

Animals↗
PubMed1975

[Ultrastructural demonstration of deoxyribonuclease-sensitive elements in fibrillar zones of the nucleoli of L 929 cell interphasic nuclei].

We have shown in our earlier paper (4) that a ribonuclease resistant filamentous network was associated with the fibrillar structures of the nucleolus of L 929 interphase nucleus. After desoxyribonuclease digestion and oxydised DAB opacification, the nucleolar fibrillar areas became heterogenous from an electron microscopical point of view. We have concluded that an important part of these fibrillar areas are composed of DNA and that the high electron dense fibrillar structures seen after desoxyribonuclease digestion, are the primary ribosomal gene product, just transcribed on the DNA matrix.

Cell Nucleolus↗
PubMed1975

[Electron microscopic demonstration of links between DNA filaments and fibrillar areas of nucleolar RNA in interphase nuclei of L 929 cells].

Electronic opacification by DAB, following ribonuclease digestion, allowed us to observe a network of DNA filaments which appeared in close relation with both intranucleolar clumps of DNA on one hand, and with the nucleolar fibrillar RNA structure on the other hand. It is inferred that the ribosomal genes may be located on these filaments of DNA.

3,3'-Diaminobenzidine↗
PubMed1975

Effect of trimethylcolchicinic acid on the synthesis and excretion of proteoglycans in tissue culture.

The action of trimethylcolchicinic acid on the synthesis and excretion of proteoglycans has been studied on the L cell strain. The incorporation of precursors has been measured, and proteoglycans produced in the culture medium have been extracted and their concentration determined. The mucopolysaccharide components have been studied by electrophoresis. Control cultures produce hyaluronic acid, dermatan sulfate and very low concentrations of chondroitin 4-sulphate or 6-sulphate. Cultures treated with trimethycolchicinic acid (4 mu g/ml) produce hyaluronic acid, very high concentrations of chondroitin 4-sulphate or 6-sulphate and only traces of dermatan sulphate. So, trimethylcolchicinic acid does not modify the synthesis of hyaluronic acid: it considerably increases the production of chondroitin 4-sulphate or 6-sulphate and inhibits the production of dermatan sulphate. Protein fraction of the proteoglycans is proportionally increased in treated cultures, but there is no marked difference between amino acid concentrations of proteoglycans extracted from control and treated cultures. A slight fall in the cystine concentrations was the only change in the amino acid content of proteoglycans extracted from treated cultures. A hypothesis to explain these results is discussed.

Amino Acids↗