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Biomedical subjects

S Bernard

Publications and source records attributed to S Bernard.

At least 19 recordsLinked to original sources
PubMed1992

Effect of fixation on the detection of transmissible gastroenteritis coronavirus antigens by the fixed-cell immunoperoxidase technique.

The effect of various fixatives and detergents on the in vitro detection of the viral determinants which are expressed in swine testis cells infected with the transmissible gastroenteritis coronavirus (TGEV) was studied using a microwell immunoperoxidase technique. When compared with glutaraldehyde and formaldehyde, 0.1% paraformaldehyde was found to be the fixative of choice for the detection of these determinants on the membranes of infected cells. Among dehydrating fixatives, 80% acetone or a mixture of acetone and ethanol or of acetone, methanol and ethanol were found to be the best fixatives for the detection of these viral determinants which are expressed in infected cells. In the case of acetone, the temperature of fixation and its concentration in the fixative preparation were found to be important. The treatment of 0.05% glutaraldehyde-fixed, infected cells with 0.1% saponin or 0.1% paraformaldehyde-fixed, infected cells with 1%NP-40 led to satisfactory detection of viral determinants. Using Triton X-100 to render cells permeable, the quantities of N and M antigen detected in TGEV-infected cells prefixed with either 0.05% glutaraldehyde or 0.1% paraformaldehyde were equal to those of 80% acetone-fixed, TGEV-infected cells while the quantity of S antigen detected was diminished. The effect of other detergents such as zwittergent, empigen BB, Chaps and N-lauroylsarcosine on the detection of viral determinants was also studied.

Acetone↗
PubMed1992

Pathogenicity and antigen detection of the Nouzilly strain of transmissible gastroenteritis coronavirus, in 1-week-old piglets.

We compared the pathogenicity and the sites of multiplication of the attenuated Nouzilly strain, with the highly passaged Purdue-115 and the virulent Gep II strains of transmissible gastroenteritis (TGE) coronavirus, in 1-week-old weaned piglets. The immunohistochemical peroxidase technique, with an antiviral nucleoprotein monoclonal antibody, was used for the localization of the multiplication sites, in the intestine and other organs. The Gep II and the Purdue-115 strains, administered orally to piglets, caused clinical signs and lesions of TGE. These strains multiplied within the intestinal tract in the enterocytes of the jejunum and ileum, Peyer's patches and mesenteric lymph nodes. In view of the small numbers of infected cells in the tonsils, spleen, kidney, liver and lung, these tissues are not considered to be preferential multiplication sites. The attenuated Nouzilly strain multiplies only in the ileum and the mesenteric lymph nodes. The variation in the tropism for particular parts of the intestine (with the preferential localization of the virus in the ileum rather than the jejunum), could be related to the high degree of attenuation of the Nouzilly strain.

Animals↗
PubMed1992

Bacillus cereus endocarditis: report of a case and review.

Bacillus cereus is a ubiquitous organism that infrequently causes serious infections. We report a patient with B. cereus endocarditis involving a mechanical aortic valve. Data for 10 cases of B. cereus endocarditis reported in the literature are summarized. B. cereus is resistant to many commonly used antibiotics, a finding that has clinical significance for empirical antibiotic selection in patients with suspected endocarditis. Infection in patients with valvular heart disease in the few cases reported is associated with significant mortality and morbidity.

Adult↗
PubMed1992

Reduction of infarct size with coronary venous retroperfusion.

BACKGROUND: The purpose of this study was to determine whether coronary venous retroperfusion with pressure-controlled intermittent coronary sinus occlusion (PICSO) alone and in combination with coronary venous substrate enhancement using L-glutamate would decrease ischemic damage after surgical revascularization for an acute coronary occlusion. METHODS AND RESULTS: In 40 pigs, the second and third diagonal vessels were occluded with snares for 90 minutes followed by 30 minutes of cardioplegic arrest and 180 minutes of reperfusion with the coronary snares released. During the period of coronary occlusion, 10 pigs received PICSO using a balloon-tipped triple-lumen catheter in the coronary sinus; 10 pigs received PICSO plus oxygenated blood transfused retrograde via the PICSO catheter (7 ml/min), 10 pigs received PICSO plus an oxygenated blood L-glutamate (13 mM) solution, and 10 pigs received neither PICSO, blood, nor L-glutamate through the coronary sinus (unmodified). Hearts treated with PICSO had higher wall motion scores (1.27 +/- 0.33 for unmodified, 2.40 +/- 0.40* for PICSO, 2.45 +/- 0.20* for PICSO plus blood, 2.85 +/- 0.30* for PICSO plus L-glutamate; *p < 0.05 from unmodified where 4 is normal to -1 is dyskinesia), lower area of necrosis-to-area of risk ratio using histochemical staining techniques (73 +/- 4% for unmodified, 27 +/- 4 for PICSO; 18 +/- 2* for PICSO plus blood, 12 +/- 1* PICSO plus L-glutamate; *p < 0.05 from unmodified), significantly less tissue acidosis (pH) compared with the unmodified group (pH, -0.41 +/- 0.13 for unmodified, -0.16 +/- 0.03* for PICSO, -0.19 +/- 0.02* for PICSO plus blood, -0.20 +/- 0.08* for PICSO plus L-glutamate; *p < 0.05 from unmodified). CONCLUSIONS: Coronary venous retroperfusion with PICSO alone and in combination with coronary venous substrate enhancement using L-glutamate significantly decreases ischemic damage during urgent surgical revascularization.

Angioplasty, Balloon, Coronary↗
PubMed1992

Protection against Chlamydia psittaci in mice conferred by Lyt-2+ T cells.

A murine model was used to study the respective roles of L3T4+ and Lyt-2+ T cells in protection against Chlamydia psittaci. Donor mice were intravenously (i.v.) infected with 1 x 10(5) plaque-forming units (PFU) per mice of live C. psittaci. One month after inoculation, splenic cells from donors were transferred into syngenic recipients (5 x 10(7) cells/mouse). As measured by splenic colonization on Day 6 after i.v. challenge (1 x 10(5) PFU/mouse), transfer with primed (untreated) cells conferred a 3 log protection in this model. In vitro treatment, before transfer, of splenic cells with anti-Lyt-2 monoclonal antibody (mAb) and complement, markedly impaired the protection in comparison with control mice transferred with primed untreated cells, whereas treatment with anti-L3T4 mAb did not reduce the transferred protection. Resistance to a reinfection with C. psittaci was also studied after selective in vivo depletion of L3T4+ and Lyt-2+ T cells. One month after primary infection, mice were treated with anti-L3T4 or anti-Lyt-2 mAb and challenged thereafter (i.v., 1 x 10(5) PFU). The splenic colonization on Day 6 after challenge demonstrated that treatment with anti-Lyt-2 mAb impaired resistance against a subsequent infection with C. psittaci. Treatment with anti-L3T4 mAb in vivo had no effect on protection, as previously described in vitro. The mechanisms by which Lyt-2+ T cells could participate in the elimination of bacteria were discussed.

Animals↗
PubMed1991

Biotin formation by recombinant strains of Escherichia coli: influence of the host physiology.

Strains of Escherichia coli were transformed with different plasmids bearing the gene clusters bioXWF and bioDAYB isolated from the Gram positive bacterium Bacillus sphaericus. These genes encode for the enzymes involved in the metabolic pathway which synthesizes biotin from the precursor pimelic acid. Transformed E. coli strains were grown in bioreactors to reach a biomass of 18 g l-1 cell dry weight in 1 litre batch culture with substrate feeding and approximately 50 g l-1 in 10 l fed batch culture. Improved yields of total vitamers and biotin formed in these processes were achieved after a comparative analysis of different culture conditions, medium compositions, host strains and expression systems. Production of 27 mg l-1 of biotin and 200 mg l-1 of vitamers was achieved in 1 litre batch culture. Using a 10-1 fed batch process, biotin and vitamer concentrations reached maximum values of 45 mg l-1 and 350 mg l-1, respectively.

Bacillus↗
PubMed1991

Fixed-cell immunoperoxidase technique for the study of surface antigens induced by the coronavirus of transmissible gastroenteritis (TGEV).

An immunoperoxidase technique performed on the TGEV-infected cells was developed for detection of virus-induced antigens. The presence of M antigen of TGEV on the surface of infected cells was demonstrated by this technique. This finding is in contrast to the M protein of murine hepatitis coronavirus which migrates to the Golgi apparatus but is not transported to the plasma membrane. The time course of appearance M and S antigens on the surface of TGEV-infected cell can be studied by this technique.

Animals↗
PubMed1991

Severe lactic acidosis following theophylline overdose.

The patient with theophylline overdose commonly presents with gastrointestinal, cardiovascular, neurologic, and electrolyte abnormalities. Respiratory alkalosis is the most common acid-base alteration, but mild metabolic acidosis has been reported. Two cases of severe lactic acidosis (pH 6.67 and 6.63) in patients without hypoxemia, shock, or prolonged seizure activity are reported. Possible causative mechanisms and aspects of therapy are discussed. Theophylline toxicity should be considered when an unconscious patient with concurrent severe metabolic acidosis presents to the emergency department.

Acidosis, Lactic↗
PubMed1979

Induction of specific anti-actin antibodies and their measurement by ELISA technique.

Using the ELISA technique we have been able to quantify antibodies directed against actin and to follow the kinetics of antibody production. Specific anti-actin antisera have been raised in rabbits by immunization with chemically modified white muscle rabbit actin. Two or three dinitrophenyl groups linked per actin molecule were sufficient to break natural tolerance, while linkage of three phosphorylcholine groups to actin was not.

Actins↗
PubMed1979

Dictyocaulus viviparus in calves: quantitation of antibody activities in sera and respiratory secretions by immuno-enzymatic analysis.

An enzyme-linked immunosorbent assay (Elisa) which is in detail described here has been adapted to trace antibody production in different fluids from infected calves. Seven calves were infected both with Dictyocaulus viviparus, and with several intestinal nematodes. Antibodies against an antigen prepared from Dictyocaulus viviparus adult worms were first detected during the 5th week post-infection, both in serum and nasal secretions, and were also observed in bronchial washings of the same calves slaughtered 53 days post-infection. IgA antibodies were never evident in the serum but were found in limited quantities in nasal secretions. In bronchial washings at slaughtering, a significant part of antibody activity is accounted for by the local IgA production.

Animals↗
PubMed1978

[Autonomic determination of proteins from urine by centrifugal and continuous flow analyses (author's transl)].

A precipitating reagent comprising partially neutralized trichloroacetic acid with magnesium sulfate, sodium dodecyl sulfate and polyethylene glycol is used for automatic determination of proteins from urine by centrifugal analysis and continuous flow analysis. We compare and discuss the results of both methods, their limits of validity and incorporation in an automated laboratory.

Albuminuria↗
PubMed1977

[Analysis of plasma urea by continuous flow method using enzymes].

An automated continuous flow method is described for the assay of plasmatic urea after hydrolysis by urease followed by NH+4 assay with glutamic-deshydrogenase. Precision and accuracy, comparison with chimical diacetyl-monoxim method are studied. The interaction of endogenous NH+4, the cost of the method are calculated.

Autoanalysis↗
PubMed1977

[Automatic dosage of total urinary proteins with centrifugal analyser].

Automatic assay of urinary total proteins on a centrifugal analyser. The assay of urinary proteins is achieved opacimetrically after precipitation by trichloracetic acid. The addition of tensio-active agents lates the initiation of precipitation, helps the formation of a microprecipitate thus hold in suspension. The technique is linear from 0 to 2,5 g/l and for every albumin/globulins ratio between pure albumin and pure globulin.

Albuminuria↗
PubMed1975

Effects of BCG, Corynebacterium parvum, and methanol-extration residue in the reduction of mortality from Staphylococcus aureus and Candida albicans infections in immunosuppressed mice.

An immunosuppressed mouse model was devised to test the effects of immunopotentiators on the prevention of bacterial and fungal infections. The effects of BCG and Corynebacterium were tested against Staphylococcus aureus and Candida albicans infection. The effect of methanol-extraction residue (MER-BCG) was tested against S. aureus septicemia. CDF mice were given various doses of BCG, 1.0 mg of C. parvum, or 0.5 mg of MER intraperitoneally at varying intervals before injection of an intravenous bacterial challenge. Four days before challenge, 300 mg of cyclophosphamide per ml was given intraperitoneally. BCG (106 colony-forming units) reduced mortality due to S.aureus at pretreatment intervals of 3, 7, 14, and 28 days. Isonicotinic acid hydrazide treatment elimated the protective effect of the live BCG. C. parvum was as effective as BCG against S. aureus septicemia when given 3 days before infection, but lost most of its protective effect after that time. MER protected at doses as small as 0.25 mg when given 25 days prior to challenge. Both BCG and C. parvum exerted a protective effect against Candida albicans infection.

Animals↗
PubMedDate not supplied

Transmissible gastroenteritis coronavirus: surface antigens induced by virulent and attenuated strains.

Three strains of the transmissible gastroenteritis virus (TGEV) possessing different degrees of pathogenicity for piglets were examined for their capacity to express M and S glycoproteins on the infected cell surface using a microwell immunoperoxidase test. These two viral glycoproteins were easily detected on the plasma membrane of 0.1% paraformaldehyde-fixed swine testis (ST) or pig kidney (RP.D) cells which were infected with high-passaged Purdue-115 and low-passaged D-52 strains and a high-passaged attenuated (188-SG) mutant of TGEV. No significant differences were found between attenuated and virulent strains with regard to the viral antigen expression on the membrane of infected cells over a 14-h period.

Animals↗
PubMedDate not supplied

Retroperfusion and balloon support to improve coronary revascularization.

Coronary venous retroperfusion and Intra-Aortic Balloon Pump (IABP) support are methods currently utilized to reduce ischemic damage prior to revascularization of acutely ischemic myocardium. This study was undertaken to determine whether combining coronary venous retroperfusion using Pressure Controlled Intermittent Coronary Sinus Occlusion (PICSO) with the IABP would result in improved salvage of ischemic myocardium. In 40 adult pigs, the second and third diagonal vessels were occluded with snares for 1 1/2 hours followed by 1/2 hours of cardioplegic arrest and 3 hours of reperfusion with the snares released. During the period of coronary occlusion prior to arrest, 10 pigs received the IABP, 10 had PICSO, 10 had PICSO+IABP, while 10 had no intervention (Unmodified). Ischemic damage was assessed by echocardiographic wall motion scores, myocardial pH, and the area of necrosis/area of risk using histochemical staining. Both PICSO and the IABP alone significantly reduced ischemic damage. However, the best wall motion scores, highest pH, and least necrosis was seen in the IABP+PICSO group. We conclude that the combination of coronary venous retroperfusion using PICSO and the IABP results in the most optimal recovery of acutely ischemic myocardium during emergent surgical revascularization.

Animals↗