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Biomedical subjects

P Auger

Publications and source records attributed to P Auger.

At least 55 records · Page 3Linked to original sources
PubMed1989

Biotyping of Candida albicans: results of an international collaborative survey.

An agar plate system for biotyping isolates of Candida albicans was evaluated in four laboratories for 18 coded yeast isolates, each tested in triplicate on duplicate series of agar plates. The results showed that the biotyping system gave excellent intralaboratory reproducibility. However, because the concordance of data among laboratories was poor, the method must be regarded as suitable only for research applications and not for routine use.

Candida albicans↗
PubMed1989

Treatment of cutaneous candidosis in guinea pigs: effect of zinc oxide on the antifungal efficacy of nystatin.

This article describes the in vivo evaluation of a new topical preparation (Zincostatin) indicated for Candida albicans infected diaper rash. In order to study the influence of the 20% zinc oxide (W/W) (a protectant) on the anti-candidal efficacy of the 100,000 U/g of nystatin found in the ointment, groups of guinea pigs received different treatments with or without local occlusion. Zinc oxide, nystatin, or the combination of both were applied, in the ointment base, on the backs of the animals inoculated with a fresh strain of Candida albicans. Macroscopic and microbiological evaluation of the skin lesions were assessed at regular intervals during 21 days. While the two treatments containing nystatin were more effective than zinc oxide alone, the latter agent did not decrease the efficacy of the antifungal drug in combination therapy. Also, zinc oxide seemed to afford some protection against local maceration induced by occlusion, which increased the severity of the infection.

Animals↗
PubMed1988

Reduction of energy required for defibrillation by delivering shocks in orthogonal directions in the dog.

Reduction of energy required to defibrillate (ERD) seems to represent a necessary condition for intensive development of implantable defibrillator, so as for minimization of cardiac and pulmonary damages provoked by high energy transthoracic defibrillation electric shocks. The present work describes a defibrillation method using shocks delivered in orthogonal directions and separated by a 100 ms delay. Defibrillation threshold measured with classical unidirectional shocks on 30 dogs has been found to be 286.8 +/- 22.2 joules. In the same animals, defibrillation threshold measured by use of orthogonal shocks has been found to be 101.4 +/- 14.9 joules. We conclude that this crossed shocks method leads to a substantial reduction of ERD (64%).

Animals↗
PubMed1988

Genetics of resistance to infection with Candida albicans in mice.

To determine differences in susceptibility, 234 naive mice including xid and beige mutants were infected intravenously with Candida albicans and monitored with survival analysis and quantitative culture of the kidneys. By using survival time as the criterion, animals of seven inbred strains were separated into three groups. C3H/HeJ and Dw/+ were most susceptible; C57BR/cdJ, BRVR and CBA/N (xid) were intermediate in susceptibility; C57BL/KsJ and C57BL/6J were least susceptible. Mean survival times (MST) were markedly influenced by the number of Candida cells injected while the ranking of mouse strains by survival alone was unchanged. There was a dissimilar behaviour of the strains to produce organ weight changes in response to infection when compared with uninfected mice which were matched for age and genetic lineage. Black mice had lower colony forming units (CFU) per mg of tissue at the time of death than animals of other genetic lineage. Nevertheless, the finding that MST and CFU studies were loosely correlated in a few strains of mice indicated that the proliferation of the fungus in the kidneys was not always the major cause of death. The beige mutation was found to determine an increased susceptibility to systemic Candida infection. The differences in survival for beige and nonbeige mice were influenced by the genetic lineage of the host, being much greater in the C57BL/6 strain (36.7 days) than in the C3H/He strain (5 days). C57BL/6 beige-J had significantly higher CFU per organ and per unit of weight than C57BL/6 +/+ mice. These data evinced an important contribution of host genetic factors to resistance to systemic candidiasis. It is suggested that innate resistance genes regulate the differentiation in the bone marrow and the function of cells of granulocyte-macrophage lineage.

Animals↗
PubMed1987

[Prevention of infectious endocarditis following manipulations of the urogenital tract].

Instrumentation of the genito-urinary tract may cause transient bacteremia, it can result in bacterial endocarditis in predispose subject. We studied the incidence of transient bacteremia following urogenital procedure and discovered a 2.6% rate in 196 patients. Therefore we studied antimicrobial prophylaxis against strains isolated from urocultures (35 strains) and blood cultures (6 strains). The strain's minimal inhibitory concentration (MIC) confirms antibioprophylaxis suggested by American Heart Association (AHA). Mean-while, according to our results, netilmicin is the best choice.

Adolescent↗
PubMed1986

Monoclonal antibodies against Candida tropicalis mannan: antigen detection by enzyme immunoassay and immunofluorescence.

Three strains of mice were immunized with Candida tropicalis cell walls, and antibodies against mannan were detected by indirect enzyme immunoassay (EIA) in 3 of 9 BALB/c mice, 4 of 11 C57BL/6 mice, and 4 of 8 CFW mice. Responding mice produced immunoglobulin M (IgM), but IgG was not detected in their sera. Fusion of the high-responder BALB/c mouse with a plasmacytoma cell line resulted in 41 clones secreting antimannan monoclonal antibodies (MAbs). Four clones selected for propagation included one IgM and one IgG MAb that reacted with mannans of Candida albicans serotypes A and B and of C. tropicalis and two IgM MAbs specific for an epitope only in the mannans of C. albicans serotype A and C. tropicalis. One of the IgM MAbs, CB6, was an effective substitute for rabbit antibodies in the double-antibody sandwich EIA to detect antigenemia produced in rabbits infected with C. albicans A or C. tropicalis. It could function either as the peroxidase-conjugated indicator antibody or as the capture antibody. Two MAbs, CB6 (C. tropicalis and C. albicans A specific) and AC3 (C. tropicalis and C. albicans A and B specific), functioned in place of polyclonal antisera in the serotyping of C. albicans by immunofluorescence. There was 95.8% agreement in the results of serotyping using MAbs as reagents compared with rabbit antisera. Competitive inhibition in EIA between CB6 and monospecific antisera against C. albicans factors 1, 4, and 6 indicated that CB6 binds to an epitope which is probably factor 6. Serologic similarity between factor 4 and the binding site of MAb AC3 was also determined.

Animals↗
PubMed1985

[Actinobacillus actinomycetemcomitans infectious endocarditis. Apropos of 2 cases and review of the literature].

This work reports two cases of endocarditis caused by Actinobacillus actinomycetemcomitans. As noted in the medical literature, the mean clinical features are a subacute infection without know source of bacteremia, in a male patient aged 40 years or older and who is suffering from a heart disease. In our two presentations, the good response to single antibiotic treatment, although the optimal therapeutic approach is not yet defined, and the lack of embolism phenomena are of special interest. Spectrum of bacteria which can be responsible of infective endocarditis is widening rapidly; this study is an example of this trend.

Actinobacillus Infections↗
PubMed1985

Genetic resistance to murine cryptococcosis: increased susceptibility in the CBA/N XID mutant strain of mice.

In a survey of 301 normocomplementemic inbred mice (belonging to nine different strains: BALB/cN nu/nu and nu/+, CBA/N, C57BL/KsJ, C57BR/cdJ, CBA/CaJ, BRVR, DW/+, and C57BL/6J) for natural resistance to Cryptococcus neoformans, cumulative survival values were found to range from 12 to 22 days. When the average organ weights of infected animals were compared with reference values obtained in uninfected mice of the same age and genetic lineage, the following changes were documented. In the CBA/N strain, the mean spleen and brain weights increased 313 and 13.5%, respectively, whereas the mean liver weight remained unchanged. In the CBA/Ca strain, cerebral cryptococcosis was the dominant clinical feature, and a 54% increase in mean brain weight was recorded at the time of death. The averaged liver weight was drastically lower, whereas spleen weight values evinced a biphasic pattern of transient splenomegaly followed by involution. At the median time of death, CBA/N mice had significantly more cryptococci in the liver and spleen than corresponding CBA/Ca mice. In the (CBA/N X CBA/Ca)F1 mice, susceptibility to C. neoformans segregated according to the sex-linked inheritance of the X-linked immunodeficiency (xid) gene. It is concluded that (i) susceptibility to cryptococcosis is under multigenic control, (ii) the xid locus on the X chromosome influences susceptibility to cryptococcosis, and (iii) xid mice behave differently than CBA/Ca mice in their organ response during the course of the infection.

Animals↗
PubMed1985

Genetic resistance to murine cryptococcosis: the beige mutation (Chédiak-Higashi syndrome) in mice.

The influence of the bgJ and bg2J mutations on the susceptibility of mice to experimental cryptococcosis was studied in inbred mice of the C57BL/6J and C3H/HeJ strains. Although infected animals with the bg/bg genotype had a significantly shorter lifespan than bg/+ or +/+ animals, C3H/He beige-2J mice were less susceptible than C57BL/6 beige-J mice when compared with nonbeige mice of similar background. On days 18 and 19 after infection, quantitation of cryptococci in the brain, liver, and spleen revealed that the overall burden of organisms in infected C57BL/6 beige-J mice was in excess of one log unit above that found in the brain, liver, and spleen of infected C57BL/6 +/+ mice. At that time, C57BL/6 beige-J mice showed a 53% increase in mean brain weight, a 67.8% decrease in mean liver weight, and a 58.6% decrease in mean spleen weight, when compared with uninfected animals of the same age and genetical lineage. The corresponding figures for C57BL/6 +/+ mice were a 32% increase in mean brain weight, a 41.4% decrease in mean liver weight, and a 23.4% decrease in mean spleen weight. From these data, it is concluded that the beige mutation in mice is associated with increased susceptibility to cryptococcosis, the accrued susceptibility of the beige mutant is related to more rapid changes in the weight profile of the target organs as well as to a higher rate of growth or decreased clearance of Cryptococcus neoformans or both, and other autosomal genes are likely to be involved in the genetic control of susceptibility to murine cryptococcosis.

Animals↗
PubMed1984

Early valve replacement in active infective endocarditis.

Infective endocarditis is associated with a high mortality, but previous studies have suggested that the major complications of the condition might be prevented by early surgery. Of 50 patients treated for infective endocarditis at the Montreal Heart Institute from 1977 to 1982, 30 were treated nonsurgically and the remaining 20 underwent early valve replacement before preoperative antibiotic therapy was completed. Of these 20, 14 had native valve endocarditis and 6 prosthetic valve endocarditis. The organisms involved were Streptococcus sp in 11, Staphylococcus aureus in 2, gram-negative organisms in 3 and Candida parapsilosis in 1. Blood cultures remained negative in three patients. There were three early deaths (15%) following operation and one late death (5%). Infection on implanted prostheses did not recur, but reoperation was required in one patient because of prosthetic dehiscence 7 months after initial implantation. All resected valves displayed evidence of infection. Follow-up was obtained in all survivors. After an average follow-up of 26 months, 12 patients remained in functional class I and 4 in class II (New York Heart Association classification). Early valve replacement has resulted in improved survival of patients with infective endocarditis and is now associated with a low operative mortality and morbidity.

Adolescent↗
PubMed1983

Interactions of serotypes A and B of Candida albicans in mice.

Candida albicans serotypes A and B were mixed in different proportions and administered orally to white mice receiving a protein-free diet. Recoveries of the serotype from the stomach and rectosigmoid showed that the relative proportion of serotype A was consistently higher than in the inoculating suspension. No modification of serotype was observed in mice given only one serotype, and there was no change in proportions of serotypes coincubated in vitro. These observations indicate that host factors must be involved in selective colonization by the serotypes in vivo.

Animals↗