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Biomedical subjects

P Auger

Publications and source records attributed to P Auger.

At least 73 records · Page 4Linked to original sources
PubMed1982

Fungitoxicity of muramidase. Ultrastructural damage to Candida albicans.

The antifungal activity of hen egg-white lysozyme was investigated in vitro using a hypotonic medium designed to support an anabolic cellular state with minimal growth stimulation. The pathogenic yeast Candida albicans was found to be sensitive to microgram amounts of hen egg-white lysozyme. This susceptibility was evidenced by sluggish growth and a dose-dependent killing process. Transmitted and scanning electron microscopic observations on lysozyme-treated C. albicans yeast cells revealed the following ultrastructural modifications: (1) plasmolysis, vacuolar expansion and wrinkled surface configuration; (2) unremitting accumulation of wall-like material that bulged into the periplasmic space; (3) qualitative changes in the organization of the wall. Ongoing structural modifications within the wall were highlighted with the cationic heavy metal dye ruthenium red. A disruption in the permeability of the cytoplasmic membrane was evidenced by modification 1 and by differential staining characteristics in light microscopy. The superimposed osmotic imbalance was identified as the cause of cell death. It is proposed that lysozyme acts on C. albicans by two distinct complementary mechanisms: enzymatic hydrolysis of N-glycosidic bonds that link polysaccharides and structural proteins of the wall; injury to the cytoplasmic membrane as a result of a cationic protein kind of interaction.

Candida albicans↗
PubMed1981

[Epidemic of bacillary dysentery].

An outbreak of bacillary dysentery in 1978 affecting 928 persons, most of whom were living in the village of St-Jacques, PQ, is described. An epidemiologic study suggested the water supply as the source of the infection, and it was established that the water carried by the municipal aqueduct was contaminated by feces containing the causal agent, Shigella sonnei. This epidemic, the largest mentioned in he Canadian medical literature, demonstrates how contagious this infection is.

Adolescent↗
PubMed1981

Infective endocarditis update experience from a heart hospital.

In a retrospective study of 50 patients with infective endocarditis (IE), we found an overall mortality of 44%: among the 26 patients with natural valves (NV) the mortality was 19%; among the 24 with prosthetic valves (PV) it was 71%. Congenital heart disease was recognized in 17 of our cases, with a significant clustering in the NV group (50% vs 17%, p = 0.029); the most frequently encountered malformation was the bicuspid aortic valve. The incidence of rheumatic heart disease was 46% in the NV group and 83% in the PV group (p = 0.015). Manifestations of IE were protean and multisystemic. We calculated an average of 4.6 symptoms and 4.7 signs for each patient. Although sepsis was abated with appropriate antibiotics, death often ensued from multiple complications: congestive heart failure, arrhythmia, stroke, embolic myocardial infarction, valvular destruction or dehiscence, coagulopathy. New features of natural valve infective endocarditis are a rising incidence in the elderly and a survival rate seemingly at its peak. Features of prosthetic valve infective endocarditis include overwhelmingly frequent embolization to the central nervous system (p = 0.004), spleen (p = 0.009) and kidney (p = 0.010). Advances in therapy for this disease may come from early surgery in late prosthetic valve endocarditis and from future prospective studies to define how the host response influences the outcome.

Adult↗
PubMed1981

[Anti-Candida albicans serology. A study carried out on 178 pregnant women in labour (author's transl)].

The serological study of 178 women investigated during labor shows that the number of patients with a significant titer of Candida albicans antibodies is 161 % higher in those suffering from vulvovaginitis due to this fungus as compared to patients without current infection. Among the 30 patients having vaginitis, 73 % harbor the yeast in the gastrointestinal tract. Precipitins were present in 6 patients : all of them also have a high titer of fluorescent antibodies. From the results of this work, it can be concluded that Candida albicans serology, although still difficult in its interpretation, is an interesting tool for the clinician and for the study of the physiopathology of candidosis.

Candidiasis↗
PubMed1980

Natural occurrence of a humoral response to Candida in human amniotic fluid.

With a sensitive indirect immunofluorescent technique, we studied the antibody response to Candida albicans in 150 human amniotic fluid (AF) specimens at 15 to 18 weeks' gestation. Specific IgG was detected in 94.7% of the samples and specific IgA, in 98%, while 1.3% were negative in both tests. A comparison of the mean ratio of anticandidal titers (IgA/IgG) in AF and human serum indicated a predominance of IgA activity in AF and the reverse in serum (2.01 versus 0.66, p less than 0.001). There was no correlation between IgG and corresponding IgA titers, which supports the fetal origin of IgA. Humoral immunity alone had no discernible influence on the growth of C. albicans in midtrimester AF. It is suggested that the synthesis of specific IgA is genetically determined because it presumably offers some functional advantage over transmitted maternal IgG in the local defensive mechanisms of the amniotic cavity.

Amniotic Fluid↗
PubMed1980

Microbial flora associated with Candida albicans vulvovaginitis.

The relationship between vaginal microflora Candida albicans vulvovaginitis is studied. Results obtained from 340 vaginal specimens showed an increase of isolates in the absence of C albicans for all groups of microorganisms (168%), particularly for the gram-negative bacteria (226%). A high frequency of polymicrobial vaginitis is noted, as is the probable importance of anaerobic microorganisms. Finally, some special aspects of the pathogenesis of C albicans infection are discussed.

Candidiasis, Vulvovaginal↗
PubMed1980

Stunted growth Candida albicans in human amniotic fluid in vitro.

The interaction of human AF with the pathogenic yeast Candida albicans was studied in vitro in 262 samples from early midtrimester and term gestations. Among 111 fluids collected between 15 and 18 weeks, 84% (93) manifested growth-inhibiting activity on 10(2) fungal cells/ml at 24 hr. This phenomenon persisted to a similar extent in late pregnancy. It could not be explained by a lack of nutrients in AF, since the addition of TSB failed to influence the proportion of active fluids. Depletion of the yeast cell glycogen reserve potentiated the degree of fungistasis achieved in several samples (p = 0.0009). Supplementation with either SDB or a physiologic concentration of carbon dioxide effected a complete reversal (p less than 0.0001). Preliminary data as well as overall results suggest that the absolute transferrin content and its pH-dependent saturation with iron are key factors invovled in the growth-inhibiting activity. Germ tube formation was unrestricted in 115 second trimester fluids studied. Human AF probably helps to prevent congenital candidiasis, and this protective function must be better defined.

Amniotic Fluid↗
PubMed1979

A study of 666 strains of Candida albicans: correlation between serotype and susceptibility to 5-fluorocytosine.

The minimal inhibitory concentrations (MICs) of 5-fluorocytosine (5-FC) and the serotypes were determined for 666 strains of Candida albicans isolated from white patients in Canada. Of these strains, 495 (74.3%) were serotype A and 71 (25.7%) were serotype B. Resistance to 5-FC (MIC, greater than or equal to 25 microgram/ml) was observed in 11.3% of the serotype A strains and in 49.7% of the strains of serotype B. Most specimens were from the urogenital and respiratory tracts. The results showed the difference between the distribution of the two serotypes of C. albicans in North America and that in Europe. Serotyping of C. albicans strains by indirect immunofluorescence is a rapid means of predicting the de novo sensitivity of this year to 5-FC. The specificity of this technique for the isolated strains was approximately 79%.

Animals↗
PubMed1979

Viability assessment by dye exclusion. A fluorescent method for fungal cells.

A new fluorescent staining technique for fungi utilizes the differential affinity of dead cells for rhodamine B. A mounting medium has been devised that includes the dye. This medium allows direct processing of cells from a broth and provides optimal conditions for fluorescence intensity. Comparison with the standard methylene blue exclusion test as applied to the Candida albicans yeast phase indicates similar specificity. Various pseudohyphae and several fungi also exhibited selective uptake of the dye when killed. This technique should prove useful in studying the effect of both drugs and cells on pathogenic yeasts.

Cell Survival↗
PubMed1978

[Thalassemia in French-speaking Quebec residents].

Eighty-five cases of beta-thalassemia minor were found between January 1975 and November 1977 in 18 families of French-speaking Quebeckers without Mediterranean ancestry. Most of the families had settled in Quebec more than 200 years ago, largely in Portneuf county. This is the first report of such a number of cases of beta-thalassemia in this population. Thus, beta-thalassemia minor is a relatively common condition in Quebec and must be considered in cases of microcytic anemia without evidence of iron deficiency. The hematologic findings were similar to those reported in the past in other populations. Two cases of delta beta-thalassemia minor (in sisters) are also reported; this is the first report of such cases in French Canadians.

Female↗
PubMed1978

Favus: twenty indigenous cases in the province of Quebec.

Twenty indigenous cases of favus in two families residing in the province of Quebec were studied. Importantly, the disease, although active, remained undiagnosed for many years in most of the cases. The finding of active cases suggests that the disease is still endemic in regions previously described as harboring cases, namely the province of Quebec and possibly Kentucky.

Adult↗
PubMed1977

Serological survey for congenital toxoplasmosis among 4,136 pregnant women.

A prospective seroepidemiological survey for latent congenital toxoplasmosis was carried out among 4,136 women and 3,787 of their offspring in and around Montreal. The indirect immunofluorescent antibody test was used to titrate specific IgG and IgM antibodies and results were standardized in international units. The prevalence of antibodies was 40-8% for the mothers and 36-4% for the babies. Mean annual seroconversion rate was 0-95%. Thus, 30 women would have been expected to acquire toxoplasmosis during pregnancy: two cases only were observed and the reasons for it are discussed. Four cases of congenital toxoplasmosis were diagnosed serologically (0-1%), none of them showed any signs of illness. Preventive treatment was administered to 12 of 52 pregnant women suspected of a recently acquired infection.

Adolescent↗
PubMed1976

[Study of various factors affecting the colonization of the digestive tract in white mice by Candida albicans].

This paper deals with the quantitative localization of Candida albicans in different parts of white micr gastrointestinal tract after oral inoculation of the yeast. Animals are previously treated with ampicillin, cortisone, or estradiol. Female pregnant and normal adult mice are also used. Our results show that the number of yeasts increases respectively in small intestine, stomach, caecum, and sigmoid. As compared with normal adult mice, C. albicans is more abundant in mice treated wtih ampicillin or cortisone whereas the yeast growth is lower in pregnant animals or in mice receiving estradiol. Moreover, male animals ordinarily show higher values than those found in female mice.

Ampicillin↗
PubMed1975

[Study of various aspects of the pathogenesis of Candida albicans infections].

Nutritional competition between Candida albicans and 6 bacteria frequently found in the gastro-intestinal tract, together with the influence of the bacterial supernatant on yeast growth were studied. Our results showed that the amount of available carbohydrates in vitro was an important growth factor. Three of the 6 carbohydrates enhanced growth. The hypothesis of an antifungal substance produced by bacteria cannot be excluded though a 10% concentration of bacterial supernatant had no inhibitory effect on fungal growth and germination. In the presence of bacteria, the percentage of germ tube formation was markedly reduced in horse serum after 4 h incubation at 37 degrees C.

Animals↗