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Biomedical subjects

M Fontaine

Publications and source records attributed to M Fontaine.

At least 109 records · Page 6Linked to original sources
PubMed1985

[Uveitis in acquired syphilis].

Syphilis is a well-established cause of uveal disease and is thought to be responsible for several distinct types of intraocular inflammation. Four cases of acquired syphilitic uveitis are reported. The diagnosis was essentially based on the clinical picture, the elimination of other possible causes, the results of reliable blood immunologic tests eg, the TPHA, FTA and Nelson tests, and the rapid response to penicillin therapy. Evaluation of anti-Treponema pallidum antibodies in the aqueous humor does not contribute to the diagnosis of syphilitic uveitis. Two cases needed large amounts of penicillin (total dosage, 440 million units). Oral steroids were used to control the associated inflammatory reaction and to prevent a Herxheimer reaction. All the patients responded well to therapy.

Adolescent↗
PubMed1985

Fluid therapy trials in neonatal piglets infected with transmissible gastroenteritis virus.

The main purpose of this study was to evaluate the effectiveness of an oral fluid therapy alone or combined with parenteral administration of a 5% dextrose solution to attenuate the clinical signs and the pathophysiological consequences of transmissible gastroenteritis in neonatal piglets. Eighteen two day old conventional piglets were infected with transmissible gastroenteritis virus while six others were used as controls (Group 1). At the onset of diarrhea, infected piglets were divided into three groups of six (Groups 2, 3 and 4). Piglets in group 2 were not treated and were fed a milk replacer ad libitum. Piglets in group 3 were removed from the milk replacer and placed on an oral glucose-glycine-electrolyte solution ad libitum. Those in group 4 were placed on oral fluid therapy and received a 5% dextrose solution intraperitoneally at the rate of 25 mL/kg of body weight once a day. Blood samples were collected in heparin within minutes after the infected piglets became comatose and from the controls at four or five days of age. The following variables were measured: packed red cell volume, blood pH, total plasma protein and bicarbonate, blood urea nitrogen, and plasma glucose, creatinine, chloride, inorganic phosphorus, sodium, potassium, magnesium and calcium. Vomiting and diarrhea appeared 12 to 24 hours postinoculation in the infected piglets. There was a sudden and rapid progression into a comatose and moribund state one or two days later whether the infected piglets were treated or not.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

[Immunovirologic markers of the risk of influenza A H3N2 among swine].

A seroepidemiological survey using the radial haemolysis test has been performed on a representative sampling of the pig herds in Brittany. Since 1978, Influenza A H3N2 strains spread in that reservoir giving subclinical infections. We detected antibodies directed against the Influenza prototypes isolated during the human outbreaks from 1973 to 1977. Only one H3N2 virus was isolated in 1980: its antigenic structure was in agreement with the previous serological data. In 1984 outbreaks of swine Influenza A H3N2 occurred. The isolated viruses carried an hemagglutinin antigenically identical to the one of the 1980's strain but the neuraminidase looked clearly different. When studying the specific immune response of the young animals to the influenza infection, it appeared that the hemagglutinin of the 1984's viruses antigenically varied from the 1980's ones in about 2/3 of all the animals. With monoclonal antibodies anti N3 and N2 of the human prototypes we confirmed the data obtained in using the post infection ferret antisera. Monoclonal antibodies directed against the swine H3N2 1984 viruses are in preparation. We have no precise information so far on the mechanism of the antigenic variations.

Animals↗
PubMed1984

Localisation of a group of antigenic sites in complement component C3, and identification of a new fragmentation pattern.

Immunisation of rabbits or goats with denaturated human C3 reproducibly gives rise to an antiserum of restricted specificity which precipitates native C3, C3b and iC3b, but not C3c or C3d isolated from 'aged' serum. The antigenic sites recognised by the antiserum appear to be localised in a small segment of the polypeptide chain located close to the N-terminus of the C3b alpha' chain. Affinity chromatography using antibodies developed by this procedure reveals an unusual pattern of degradation of C3 which occurs on conventional 'ageing' of serum at 37 degrees C.

Amino Acids↗
PubMed1984

Isolation of two molecular populations of human complement factor H by hydrophobic affinity chromatography.

Human complement factor H was prepared in highly purified form from fresh serum by euglobulin precipitation, DEAE-Sephacel chromatography and Sephacryl S-300 gel filtration. This preparation allowed the recovery of 37% of the initial factor H. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed that factor H was homogeneous both in reduced and non-reduced media and exhibited a molecular mass of 150 kDa. Charge-shift experiments clearly showed the presence of hydrophobic sites in the factor H molecule. Charge shifts were observed with two detergent systems (Triton/sodium deoxycholate and Triton/cetyltrimethylammonium bromide). Factor H was able to bind to phenyl-Sepharose. This property allowed us to study two populations of factor H. These two populations exhibited the same physicochemical parameters, but revealed differences in their ability to aggregate in low- and iso-ionic-strength media. The molecular basis and biological significance of this heterogeneity are discussed.

Amino Acid Sequence↗
PubMed1984

Specificities of antinuclear antibodies detected in dogs with systemic lupus erythematosus.

Five hundred and eighty dogs with at least one clinical sign compatible with a systemic lupus erythematosus (SLE) were entered in a prospective study aimed at evaluating the prevalence of antinuclear antibodies (ANAb). SLE was diagnosed in 38 of these dogs (group A) which fulfilled at least four American Rheumatism Association (ARA) criteria; of these, sixteen had ANAb titers greater than or equal to 4096. The 23 dogs which met three or two ARA criteria (group B) had an ANAb geometric mean titer (GMT) of 259. Dogs (group C) with only 1 criterium had an ANAb GMT of 75. Anti-ds-DNA Ab were present in 6 dogs from group A (16%), and 2 dogs from group B (9%). Anti-histone Ab were present among dogs from group A, B and C with frequencies of 81%, 67% and 26%, respectively. Among dogs from group A, the ANAb titers and the levels of anti-histone Ab correlated positively when individual sera were considered. Antibodies against the soluble nuclear antigen (SNA) were detected in 74%, 39% and 13% of the dogs from groups A, B and C, respectively. Antibodies initially described in human SLE also exist in SLE dogs. Anti-Sm Ab were found in 24% of dogs in group A. With anti-RNP Ab the frequency was still lower (10%). However, two other types of anti-SNA Ab against RNAse and trypsin-resistant antigens, not found in human "reference sera", were often detected. The first type (anti-type 1 Ab) was found in 26% and 9% of group A and group B, The first type (anti-type 1 Ab) was found in 26% and 9% of group A and group B, respectively; the second type (anti-type 2 Ab) is less frequent, and was found in 13% and 17% of group A and B, respectively. It appears that testing for anti-Sm, anti-type 1 and anti-histone Ab should be performed in order to improve the diagnosis of SLE in dogs.

Animals↗
PubMed1984

Hypoglycemia: a factor associated with low survival rate of neonatal piglets infected with transmissible gastroenteritis virus.

The main purpose of this work was to study changes in the balance of fluids, electrolytes and blood metabolites in neonatal piglets with severe transmissible gastroenteritis. Six two day old conventional piglets were infected with transmissible gastroenteritis virus while six others were used as normal controls. Blood samples were collected in heparin when the infected piglets were moribund. The following variables were measured: packed red cell volume, total plasma protein and bicarbonate, blood pH, blood urea nitrogen and plasma glucose, creatinine, chloride, inorganic phosphorus, sodium, potassium, magnesium and calcium. Vomiting and diarrhea appeared 12 to 24 hours postinoculation in the infected piglets and they were moribund one or two days later. Before becoming moribund, most of the piglets fell rapidly into a lethargic and comatose state. The most evident changes in their blood variables were an increase in packed cell volume, total protein, blood urea nitrogen, phosphorus and magnesium levels and a decrease in pH and bicarbonate concentration as well as a severe hypoglycemia. The results suggest that severe hypoglycemia coupled with metabolic acidosis and dehydration might be an important factor contributing to the high mortality rates caused by transmissible gastroenteritis in neonatal piglets. The hypoglycemia results from a combination of the inadequate glucose metabolism inherent to neonatal piglets and the acute maldigestion and malabsorption resulting from the diffuse and severe villous atrophy induced by the virus.

Animals↗
PubMed1983

Isolation and characteristics of bovine pituitary secretory granules.

Secretory granules containing primarily growth hormone and prolactin were isolated from bovine anterior pituitaries. Marker enzyme analysis and electron microscopy indicated that the secretory granule fraction did not contain measureable amounts of other intracellular organelles. Such isolated granules were resistant to a variety of chemical and physical challenges including variations in osmolarity, ionic strength, EGTA, sonication, boiling, etc. The only treatments that were found to routinely result in granules lysis were alkaline pH and 0.5% SDS. Nonspecific leakage of both growth hormone and prolactin was less than 9% of total hormone pool even after a 60-min incubation. The release of prolactin but not growth hormone could be increased by lowering the free calcium concentration. Conversely, 10(-5) M ionophore A23187 caused a decrease in nonspecific hormone leakage. This raises the possibility that a nonexocytosis secretory pathway might be involved in pituitary hormone release. The initial secretory granule fraction was further purified using discontinuous sucrose gradient ultracentrifugation to yield a subfraction highly enriched in prolactin granules. These granules had the same stability characteristics as the original secretory granule fraction. The use of such granules should prove useful in our efforts to understand how calcium regulates cellular secretion.

Animals↗
PubMed1983

A hemolytic assay for clinical investigation of human C2.

The heat lability of early acting components of human complement was studied in detail. Kinetic disappearance of individual components was monitored by hemolytic assay. C2 and factor B were the most heat labile components. We took advantage of the difference in heat stability between C2 and C1 to develop a hemolytic assay for human C2.

Animals↗
PubMed1983

Nitrate and nitrite contents in Cuban cheese of the Gouda type.

The nitrate and nitrite contents in cheese of the Gouda type, produced by the Milk Complex of Havanna, were investigated and compared with those found in 5 types of imported cheese consumed in Cuba. No significant differences were found in the mean value (mean) of NaNO3, whereas in the mean value (mean) of NaNO2 differences were found when comparing all cheeses against each other. From these results it is inferred that the consumption of Gouda type cheese does not represent an important contribution to the daily intake of nitrates and nitrites, precursors in the synthesis of cancerogenic N-nitroso compounds.

Cheese↗
PubMed1983

Antimelanoma hybridoma antibodies against partially purified melanoma antigen.

We have immunised BALB/c mice with a melanoma antigen obtained after papain solubilisation of the membranes of a metastatic melanoma tumour and fused the immune spleen cells to the mouse myeloma line P3-NS1/1-Ag4.1. The produced hybridoma antibodies (Mel-PV antibodies) recognised the initial melanoma antigen in haemagglutination, but did not react with any of the HLA phenotypes tested by cytotoxicity on a panel of B lymphocytes with known HLA-A and B phenotypes. We rosetted red blood cells coated with protein A with dispersed cells from fresh melanoma tumours, and a high degree of specificity for human malignant melanocytes was observed. Purified Mel-PV antibodies were also tested by indirect immunofluorescence and found to be oriented towards cytoplasmic components of malignant melanoma cells. These results indicate that the use of melanoma antigens for preparing monoclonal antibodies maintained a satisfactory degree of specificity and may be an adequate starting point for defining common and specific antigenic determinants on human melanoma.

Animals↗
PubMed1983

Regulation of the binding of C3-coated particles to human lymphocytes by human complement component H.

Human complement component H was found to modify greatly the binding of C3-coated particles to lymphocytes. We used an experimental model in which lymphocytes were mixed successively with various amounts of H and C3b-coated erythrocytes. At least three mechanisms were postulated to interpret the phenomenon: (i) release of endogenous I by lymphocytes triggered by H through specific binding sites, (ii) cleavage of iC3b by I, promoted by complement receptor type one, and (iii) inhibition of immune adherence by H. Such qualitative and quantitative changes in C3-coated particle recognition by the binding sites might mediate important functions of lymphocytes.

Binding, Competitive↗