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Biomedical subjects

M Aubert

Publications and source records attributed to M Aubert.

At least 37 records · Page 2Linked to original sources
PubMed1999

The herpes simplex virus type 1 regulatory protein ICP27 is required for the prevention of apoptosis in infected human cells.

The herpes simplex virus type 1 (HSV-1) ICP27 protein is an immediate-early or alpha protein which is essential for the optimal expression of late genes as well as the synthesis of viral DNA in cultures of Vero cells. Our specific goal was to characterize the replication of a virus incapable of synthesizing ICP27 in cultured human cells. We found that infection with an HSV-1 ICP27 deletion virus of at least three separate strains of human cells did not produce immediate-early or late proteins at the levels observed following wild-type virus infections. Cell morphology, chromatin condensation, and genomic DNA fragmentation measurements demonstrated that the human cells died by apoptosis after infection with the ICP27 deletion virus. These features of the apoptosis were identical to those which occur during wild-type infections of human cells when total protein synthesis has been inhibited. Vero cells infected with the ICP27 deletion virus did not exhibit any of the features of apoptosis. Based on these results, we conclude that while HSV-1 infection likely induced apoptosis in all cells, viral evasion of the response differed among the cells tested in this study.

Animals↗
PubMed1999

Comparison of visual microscopic and computer-automated fluorescence detection of rabies virus neutralizing antibodies.

The rapid fluorescent focus inhibition test (RFFIT) and the fluorescent antibody virus neutralization test (FAVNT) are both diagnostic tests for determining levels of rabies neutralizing antibodies. An automated method for determining fluorescence has been implemented to reduce the work time required for fluorescent visual microscopic observations. The automated method offers several advantages over conventional visual observation, such as the ability to rapidly test many samples. The antibody titers obtained with automated techniques were similar to those obtained with both the RFFIT (n = 165, r = 0.93, P < 0.001) and the FAVNT (n = 52, r = 0.99, P < 0.001).

Animals↗
PubMed1999

Rabies mass vaccination campaigns in Tunisia: are vaccinated dogs correctly immunized?

Among the 301 dogs vaccinated against rabies in a suburban area of Tunis, 165 were sero-surveyed for 13 months. One month after vaccination, 65% of the dogs less than 1 year of age and 76-84% of the older dogs had significant antibody titers. One month after annual revaccination, these percentages ranged between 92% and 100%. Puppies (less than 3 months old) responded to vaccination with no significant interference by passive maternal immunity. Based on these percentages, a 93% rate of protection may be expected for vaccinated dogs. This study confirms that all dogs (even those less than 3 months of age) must be vaccinated during mass campaigns. The expected protection conferred by locally produced potent vaccines reaches 79-99% based on the age of the dogs. The alleged relative inability of local dogs to respond to vaccination cannot explain the partial success of rabies control in Tunisia.

Age Factors↗
PubMed1998

Development of a fluorescent antibody virus neutralisation test (FAVN test) for the quantitation of rabies-neutralising antibody.

A microtest named the FAVN test (fluorescent antibody virus neutralisation test), which is an adaptation of the original rapid fluorescent focus inhibition test (RFFIT) has been developed and evaluated. One hundred percent specificity was estimated using 414 sera from dogs sampled in rabies-free areas or from non-vaccinated animals. The accuracy as determined by the agreement between observed and expected values using sera of known titres was satisfactory. Serum samples from unvaccinated and vaccinated dogs (using sera with titres near 0.5 IU/ml) were assayed for rabies antibody by the FAVN test, the RFFIT and the mouse neutralisation test (MNT): comparative results obtained on the same sera with the three tests showed good agreement. Furthermore, distinguishing negative sera from positive sera with low titres is much easier with the FAVN test than with the RFFIT.

Animals↗
PubMed1998

Glucocorticoids provoke a shift from alpha2- to alpha1-adrenoreceptor activities in cultured hypothalamic slices leading to opposite noradrenaline effect on corticotropin-releasing hormone release.

We have shown previously that noradrenaline (NA) stimulated or inhibited the release of corticotropin-releasing hormone (CRH) according to the availability of adrenal steroids. The aim of the present work was to examine whether the changes in the NA modulation of CRH release from hypothalamic neurons result from a steroid-induced plasticity of the adrenergic transduction pathways. From anterior hypothalamic slices cultured in standard medium (i.e., containing adrenal steroids at a final dilution of 61 +/- 9 ng/ml), (a) the stimulatory effect of NA on CRH release was reversed in a dose-dependent manner by increasing concentrations of the alpha1-adrenoreceptor antagonist prazosin, (b) activation of protein kinase C by acute treatment with phorbol 12-myristate 13-acetate (0.5 microM, 1 h) mimicked NA stimulation of CRH secretion, and (c) the activation of L-type Ca2+ channels by Bay K 8644 also produce an increased CRH secretion. In contrast, the inhibitory effect of NA on CRH secretion from slices cultured in steroid-free medium was markedly reversed by the alpha2-adrenoreceptor antagonist yohimbine, by pretreatment with pertussin toxin, or by the addition of 4-aminopyridine, a K+-channel blocker. Acute treatment with phorbol 12-myristate 13-acetate did not change the inhibitory NA effect. Moreover, all these effects were reversed by daily corticosterone supplementation, for as long as they were tested. These results are consistent with a steroid-dependent change in the nature of adrenergic receptors and its associated transduction pathways involved in the regulation of CRH secretion in the hypothalamus.

4-Aminopyridine↗
PubMed1998

[The Roman legionnaire, the misunderstood athlete].

The author's purpose was to compare through twenty centuries expenditure of energy in raman legionnaires and its alimentary covering with those observed nowadays amidst soldiers and sportsmen. Daily expenditure of energy can be estimated at 5000 kcal for the legionnaire performing engineer work and at 6000 kcal when he was in war action. Every man was given daily by the supply corps: 1 kg of wheat, 100 g of bacon, 30 g of cheese, for a total around of 3500 kcal. This ration was planned to cover basic needs. The search for complements was left to the legionnaire's initiative. Nowadays, only workmen and sportsmen reach such a level of energy expenditure. Unless completed by an exogenous supply, legionnaire's daily ration was unbalanced, with 78% carbohydrates. On the other hand, it had the advantage of providing slow carbohydrates, of being highly energizing and easily digestible. It provided a good intestinal ballast and was fairly fitted to restore the energetic reserves of the organism. Due both to intuition and to necessity, the essential needs were covered. But, at a long time range, legionnaires were hazarding deficiency.

Diet↗
PubMed1997

[Current status of animal rabies in France].

The main host reservoir and vector of rabies in Western Europe is the red fox (Vulpes vulpes). A vaccination strategy for this species has been developed and tested in Switzerland since 1978. Results indicate that the vaccine which is administered in spring and autumn for at least two consecutive years is more effective than destruction by shooting or gassing the animals. The same approach using bait containing increasingly effective and safe vaccines has been in use in France since 1986. By creating an immunological barrier from the English channel to the Swiss border, it has been possible to stop the southern progression of the disease. In the following years the vaccination program was extended to all contaminated areas in France (141,700 km2). From 1989 to 1996 rabies decreased in incidence by 99.7% and disappeared from 95% of the previously contaminated area. Although no case of rabies involving a non-flying mammal has been reported since October 1996, rabies cannot be considered as eradicated as long as places of active disease subsist in neighboring areas of Belgium and the Sarreland. Bat rabies in Europe is caused by two viral genotypes that have never been isolated in any species other than bats and man. A total of four cases of bat rabies have been diagnosed in France since 1989. All four cases occurred in the Serotine community including one in 1997. All cases of canine rabies reported in the last 20 years have been observed in imported animals. The last was in 1995 and could have been prevented by stricter border control.

Animals↗
PubMed1996

Improvement of a polymerase chain reaction assay for the detection of Echinococcus multilocularis DNA in faecal samples of foxes.

A polymerase chain reaction (PCR) method was developed in order to permit a sensitive and specific identification of Echinococcus multilocularis DNA from fox faecal specimens. In an attempt to overcome problems related to the presence of endogenous PCR inhibitors in faecal extracts, we investigated a DNA extraction technique using an anion binding resin (Gene-Fizz). This simple and rapid procedure was applied to 61 faecal samples. Compared with the traditional microscopic examination, the sensitivity of PCR using Gene-Fizz was 82.3% and the specificity was 95.5%. No PCR signal was obtained for 20 Echinococcus granulosus isolates, showing that this method allowed discrimination between E. multilocularis and E. granulosus. Large-scale epidemiological surveys of fox excrements may be possible by using Gene-Fizz treatment prior to PCR amplification reactions.

Animals↗
PubMed1996

Safety study of the SAG2 rabies virus mutant in several non-target species with a view to its future use for the immunization of foxes in Europe.

The safety of the SAG2 virus, a low virulence mutant of the SAD strain, was investigated in ten species of mammals and seven species of birds liable to consume vaccine baits. These species are the western hedgehog (Erinaceus europaeus), the meadow vole (Microtus arvalis), the bank vole (Clethrionomys glareolus), the water vole (Arvicola terrestris), the field mouse (Apodemus flavicollis or A. sylvaticus), the Norway rat (Rattus norvegicus), the european badger (Meles meles), the domestic ferret (Mustela putorius furo), the wild boar (Sus scrofa), the domestic goat (Capra hircus), the carrion crow (Corvus corone), the rook (Corvus frugilegus), the buzzard (Buteo buteo), the red kite (Milvus milvus), the tawny owl (Strix aluco), the long-eared owl (Asio otus) and the barn owl (Tyto alba). The vaccine was administered orally to each species, by an intramuscular (i.m.) route to the rodents and ferret, and by an intracerebral route to the field mouse. No pathogenicity was observed in the 169 animals vaccinated throughout an observation period of over 30 days. After euthanasia, no rabies virus could be detected either in the brain or in the salivary glands of any of the animals. The SAG2 virus administered orally, triggered a specific seroconversion in the field mouse, wild boar, ferret and most of the raptors. Following administration by the i.m. route, specific antibody titres were observed in most of the rodents, as well as in the ferrets.

Animals↗
PubMed1996

[Right-to-left interatrial shunt with normal pulmonary pressures after pneumonectomy. Apropos of a case with severe cyanosis following left pneumonectomy].

Atrial septal defects usually give rise to left-to right in the absence of obstruction of the pulmonary outflow tract or pulmonary hypertension. The authors report a case of atrial septal defect with a right-to-left shunt despite normal pulmonary pressures at catheterisation in a 56 year-old-man who had undergone left pneumonectomy 6 months previously. The shunt was responsible for major arterial desaturation aggravated by the left lateral or dorsal decubitus position. Surgical closure of the defect resulted in cure with disappearance of cyanosis and normalisation of blood gases. The physiopathological mechanisms of these right-to-left shunts with normal pulmonary pressures are discussed with reference to previously reported cases in the literature.

Blood Gas Analysis↗
PubMed1996

[Envenomation by exotic snakes].

Snake bite envenoming in tropical areas affects an estimated one million people according to the World Health Organization. Two studies showed that annual mortality is between 30,000 and 50,000 people. Clinically cobra and viper envenoming are the most well known but several other snakes cause characteristic manifestations allowing species-specific diagnosis. Immuno-enzymatic tests are a useful diagnostic tool that is currently expanding but remains available only in developing countries because of cost. Treatment consists mainly of serotherapy in the most severe cases. Use of purified products and fragments active specifically on toxins and enzymes is both safer and more effective. Heparinotherapy should be used only when indicated by clinical manifestations and hemostasis testing. Management of envenoming must be organized in function of antivenom availabilities in a given region. Future improvements in immuno-enzymatic tests and antivenoms should allow more successful treatment of severe snake bite envenoming.

Animals↗
PubMed1995

[Epidemiology and campaign against rabies in France and in Europe].

The red fox (Vulpes vulpes) is the reservoir and vector of rabies in Western Europe. Field trials to vaccinate it with vaccine-baits dispatched in the fields were carried out in Switzerland since 1985. When repeated twice a year in Spring and Autumn, for at least two years successively, this method was proven to be more efficacious to eliminate rabies than the destruction of fox population by shooting or gassing. Since 1986, the same technique was used and adapted in France with baits carrying various vaccines. By establishing an immunological barrier from the English channel to the national border with Switzerland more than 630 km long and 35 to 80 km wide, the advance of the disease towards south was stopped. During the following years, the vaccination plan has been extended to cover the whole contaminated area in France (at most: 141,700 km2). From 1989 to 1994, the rabies incidence has been decreased by 98%. Elimination of rabies in France is now depending on the treatment of the disease in the neighbouring countries. At least, 13 other European countries are vaccinating foxes against rabies. Currently over 14 million vaccine baits are dropped annually from aeroplanes or distributed by hunters. As a result of oral immunisation there has been a sharp decrease in the number of rabies cases in animals in Western Europe. A complete elimination of rabies has been achieved over large areas, where vaccination is no longer needed. Summing up the results of oral vaccination programs carried out in Europe, it appears that reinfections have occurred due to various causes: budgetary restrictions limiting either the number of campaigns or the size of the possible vaccination zones and also cross-border contamination. Today the clearing of the western European peninsula from to east appears technically possible but the increase of fox population, and the cost of these operations are new challenge to tackled.

Animals↗
PubMed1994

Control of rabies in foxes: what are the appropriate measures?

Until recent years, the depopulation of reservoir species was the only feasible measure to break the transmission chain of rabies in wildlife. In Europe at the beginning of this century, when applied with compulsory muzzling and restrictions on movement, dog depopulation was shown to be effective before any large scale vaccination of dogs. Some examples of the success of the application of depopulation measures on wild carnivores in the past are described. But in the case of enzootics of rabies in the fox, the control measures applied to fox populations sometimes decreased the prevalence or postponed the invasion of an area but did not free or protect an area permanently. Some examples taken from France illustrate the difficulties of drawing clear conclusions from the results of control measures. Conversely, the oral vaccination of foxes was demonstrably successful in preventing the spread of rabies. However, mathematical modelling, historical considerations and first observations in areas in which foxes have been vaccinated strongly suggest that the 'traditional' methods of controlling fox populations, at least by hunting, should not be restricted because they complement the effects of vaccination.

Animals↗
PubMed1993

Primary structure analysis of a duplicated region in the amplifiable AUD6 locus of Streptomyces ambofaciens DSM40697.

In Streptomyces ambofaciens, an amplifiable unit of DNA (AUD6) contains two homologous sequences, one located on the right extremity of the AUD (S1R), the other being internal (IHS). This paper presents the molecular analysis of this duplication. The nucleotide sequences are almost identical (95%) and each contains an ORF of about 330 codons, the two ORFs being nearly identical. The two hypothetical proteins, deduced from these sequences, show about 30% identity with different bacterial repressors. They also show a particularly strong similarity (90% identity between the full-length sequences) with hypothetical proteins of Streptomyces lividans 66 encoded by sequences also present on an amplifiable DNA region (AUD1).

Amino Acid Sequence↗