[Antidigoxin Fab fragments and digoxin monitoring: a challenge for the biologist]. / Suivi des digoxinémies chez les patients traités par fragments Fab antidigitaliques: un défi pour le biologiste.

Following administration of anti-digoxin Fab fragments, monitoring unbound digoxin concentrations may help ensure appropriate dosing, and prevent recrudescent toxicity. Ultrafiltration by using Centrifree system and measurement of digoxin in the ultrafiltrate is considered as reference technique. However, ultrafiltration method is cumbersome, costly, and some immunoassays are affected by matrix differences. Another approach is to analyse the serum directly by digoxin immunoassays without ultrafiltering it. The validity of results obtained depends on the architecture of the immunoassay and the amount of Fab in the sample. The old radioimmunoassays and usually the other competitive immunoassays give inaccurate results. The fluorescence polarization immunoassay (FPIA) slightly underestimates the total digoxin concentrations. Total digoxin levels obtained at 24 hours and 48 hours after treatment permit measurement of the half-life of digoxin Fab complexes and can be used to estimate when the patient can be redigitalized, if necessary. The sequential immunoassays usually overestimate the free digoxin concentrations. The differences observed are >25% and cannot be explained solely by albumin binding (normal range, 20% +/- 5%). To date, ultrafiltration remains the best strategy for accurate determination of digoxin concentrations in the presence of antidigoxin Fab fragments.

[Acute erythermalgia: look for mushrooms!]. / Erythermalgie soudaine: cherchez le champignon!

INTRODUCTION: To describe the first European observation of erythromelalgia due to mushroom poisoning. EXEGESIS: Seven cases observed and followed over 4 years are reported. All ill patients had eaten the same mushroom species, gathered in the same French alpine valley. Clinical features of erythromelalgia were observed. This syndrome was first described in Japan after Clitocybe acromelalga ingestion. It had never been observed in Europe before. Clitocybe acromelalga does not grow in Europe. Clitocybe amoenolens was identified as the possible cause of poisoning in our cases. This species can be confused with an edible mushroom, Lepista inversa. CONCLUSIONS: Even in Europe, recent mushroom poisoning is a possible cause of erythromelalgia.

Erythromelalgia and mushroom poisoning.

OBJECTIVE: To report the first European observations of erythromelalgia due to mushroom poisoning. METHODS: Clinical features of erythromelalgia were observed in 7 cases seen over 3 years. All patients had eaten the same mushrooms species, gathered in the same French alpine valley. Erythromelalgia was first described in Japan after Clitocybe acromelalga ingestion. Clitocybe amoenolens was identified as the possible cause of poisoning in our cases.

[Forum on bacterial resistance]. / Forum sur les résistances bactériennes.

Recently, in daily newspapers and on television, attention of the audience has been focused on the overuse of antibiotics and on the role it plays in the emergence and dissemination of resistance mechanisms in the human environment. The role of food from animal origin in relation to the use of antibiotic resistance, infectious diseases, medical practice and ENT infections have accepted to answer a series of questions concerning risks versus usefulness of antibiotic usage. From the answers, we may note convergent views and discrepancies: (i) there was agreement concerning the unnecessary prescription of antibiotics in rhinopharyngitis and few other common viral infections; (ii) the risk of misuse of antibiotics in patients with poor compliance and further risk of erroneous self prescription of the remaining tablets has been cited; (iii) in the problem of resistance resulting from growth promoting antibiotics in animals, it has been experimentally shown that from 2 bacteria of the same species introduced in the animal gut, one susceptible, the other resistant, the latter will be eliminated by means of the "barrier effect"; similarly in case of transfer of resistance from an exogenous bacteria to a "resident" organism of the gut, the latter will be eliminated by the homologous susceptible ones; only an antibiotic therapy may confer importance to the resistant bacteria. In this respect, care should be taken for resistance spread such as that concerning penicillin-resistant pneumococci and surveillance and control of resistance mechanisms has become necessary. However we should look with reluctance at the diffusion of inevitably simplified and truncated information from Media, showing the negative aspects of antibiotics only. Moreover, as underlined by the expert from the Institut Pasteur, there are new perspectives in the development of effective new agents based on the modern "genomic" research.

Isolation and characterization of a plasmid from Lactobacillus fermentum conferring erythromycin resistance.

Lactobacillus fermentum is a lactic acid bacterial species commonly found in the digestive tracts of pigs and rodents and also present in man. We characterized a 5.7-kb plasmid, pLEM3, conferring erythromycin resistance, which was isolated from a porcine strain of L. fermentum. Plasmid pLEM3 established efficiently in L. fermentum, conferred high-level erythromycin resistance (MIC > 1 mg/ml), and was segregationally stable. A deletion derivative of pLEM3, called pLEM5, was constructed and found to be as genetically stable as the parent. A multiple cloning site was inserted into pLEM5, generating plasmid pLEM7. Nucleotide sequence determination of pLEM5 revealed similarities with known genes. The replicon itself is a member of the pC194 family of rolling circle plasmids. The region responsible for erythromycin resistance was 98.2% identical to the erm gene of conjugative transposon Tn1545.

Study of gene transfer in vitro and in the digestive tract of gnotobiotic mice from Lactococcus lactis strains to various strains belonging to human intestinal flora.

The use of genetically modified organisms (GMO) in dairy products requires evaluation of the DNA transfer capacity from such organisms among the human intestinal microflora. Thus, both in vitro and in vivo [in the digestive tract (DT) of mice] transfer from Lactococcus lactis donor strains of the conjugative plasmid pIL205 (CmR) and the non-conjugative plasmid pIL253 (EmR) to: (1) recipient strains isolated from human faecal flora Bacteroides sp., Bifidobacterium sp., Peptostreptococcus sp. (strictly anaerobic bacterial strains) and Enterococcus faecalis, (2) a whole human faecal flora, was studied. In both cases, no gene transfer was observed to strictly anaerobic bacterial strains. DNA transfer was only observed to the E. faecalis strain: in vivo CmR E. faecalis transconjugants were isolated from sequentially multi-associated mice and when the recipient strains associated with the mice, they were a defined mixture of Bacteroides sp., Bifidobacterium sp., Peptostreptococcus sp. and E. faecalis strains. When mice were associated with the whole human faecal flora, the plasmid pIL205 was transferred into some facultative anaerobic streptococci. It was also shown that DNA transfer occurred even when the lactococcal donor strain was transient in the DT of the gnotobiotic host animals.

Gene transfer from engineered Lactococcus lactis strains to Enterococcus faecalis in the digestive tract of gnotobiotic mice.

The introduction of genetically modified organisms into food products requires an evaluation of the behaviour and the dissemination of foreign genes of such organisms among the human intestinal microflora. The conjugal transfer, both in vitro and in vivo (in mice digestive tract) of DNA from Lactococcus lactis donor strains to an Enterococcus faecalis strain isolated from human faecal flora was studied. We followed the transfer of (1) the self-transmissible plasmid pIL205; (2) two non-self-transmissible but mobilizable plasmids, pIL252 and pIL253; (3) one plasmid, pMS1.5B, integrated into the chromosome of L. lactis. In vitro, the transfer frequency of pIL205 (expressed as the number of transconjugants per donor cell) was 9.6 x 10(-4); mobilization of one of the non-self-transmissible plasmids, pIL253, was observed (4.9 x 10(-7)). In vivo, only transfer of pIL205 and pIL253 occurred, but the frequency was not determined. The transfer of pMS1.5B was not detected in vitro or in vivo.

Influence of the bacterial flora on collagen-induced arthritis in susceptible and resistant strains of rats.

Collagen-induced arthritis is an experimental model for rheumatoid arthritis which can be elicited in susceptible strains of rats by intradermal injection of native type II collagen. In order to investigate whether bacterial flora may alter the pathogenic response to type II collagen, we have immunized germ-free (GF) male rats from either highly resistant Fisher (F344) or highly susceptible Dark Agouti (DA) strains. The disease was markedly enhanced in GF DA as compared to conventional (CV) DA rats. The humoral response was also stronger in GF rats of both strains. Neither GF nor CV F344 developed arthritis, although GF F344 exhibited later inflammation of the tail. These data support a suppressive influence of bacterial flora on collagen-induced arthritis.

[Development, equilibrium and role of microbial flora in the newborn]. / Installation, équilibre et rôle de la flore microbienne chez le nouveau-né.

Development of the digestive tract intestinal flora is the result of a specific selection process to which the multiple maternal or environmental bacteria that penetrate into the neonatal gut are subjected. In breast-fed infants, Escherichia coli and streptococci are the first bacteria to appear in the gut. They are usually, but not always, followed by a population of Bifidobacterium which quickly becomes predominant. In bottle-fed infants, the intestinal flora is more variable and often includes, in addition to the organisms mentioned above, other enterobacteria and a wider range of obligate anaerobes. Studies of experimental models have shown that the nature of milk fed to the offspring and even the lactating mother's diet have substantial effects on the sequence of development of the neonatal intestinal flora. A large number of factors capable of inhibiting or permitting in vitro growth of various bacterial species have been identified in milk. However, no in vitro activity of these factors added to milk has ever been demonstrated. These factors include "bifidus factors", which promotes the growth of Bifidobacterium, and lactoferrin and immunoglobulins, which prevent colonisation of the gut by pathogenic enterobacteria. Immune factors in milk play a key role in interactions between the microbial flora and gut mucosa. However, they seem to have no effect on the growth of bacterial populations in the gut lumen. A number of pioneer bacteria, which are the first to arrive in the gut, are capable of effectively blocking growth of other bacteria introduced later in the ecosystem. In some instances, these pioneer bacteria also inhibit production of toxins by pathogenic species. Consequently, it is important to adhere to the recommended gradual changes in diet which allow these species to sequentially colonize the gut.

Colonization of the digestive tract of germ-free mice by genetically engineered strains of Lactococcus lactis: study of recombinant DNA stability.

The ability of genetically engineered Lactococcus lactis strains to become established in the digestive tract (DT) of germ-free mice was examined together with the stability of their genetic markers. Seven L. lactis strains were genetically modified by insertion of genetic markers on different replicons: chloramphenicol resistance gene cat was carried by self-transmissible plasmid pIL205, a derivative of plasmid pIP501; erythromycin resistance gene erm, originating from pAM beta 1, was inserted into non-transmissible plasmids pIL252 and pIL253 of low and high copy number respectively; erm gene from plasmid pMS1.5B was inserted into the chromosome. All strains carried a common wild-type plasmid pIL9 involved in lactose fermentation. It was observed that the DT of mice was rapidly and efficiently colonized with either the inoculated parental strain or with its derivatives or with both of them, but plasmid-free derivatives were always at dominant levels. Both plasmids pIL9 and pIL205 were lost, but the parental strains and the plasmid-lacking derivatives were at codominant levels, indicating that there is an equilibrium between plasmid loss and plasmid transfer in the DT. Strains that carried non-transmissible and low copy number plasmid pIL252 were rapidly eliminated from the DT, which in turn was colonized with the respective pIL252-less derivatives; this is probably due to the high segregational instability of pIL252.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of gut wall paf-acether and precursors by intestinal microflora.

Comparison between holoxenic and axenic mice led to the conclusion that the presence of an intestinal microflora produced a decrease in wall paf in conventional mouse caecum, whereas an increase in wall lyso-paf and alkyl-acyl-glycerophosphocholine (A-A-GPC) content was noticed. By contrast, the presence of flora had no significant incidence on wall paf, lyso-paf and A-A-GPC content of conventional mouse jejunum. Thus, the modulation of gut wall phospholipid composition by intestinal microflora is evidenced for the first time.

[Neuropsychic effects of cimetidine and ranitidine. Apropos of 1 case]. / Effets neuropsychiques de la cimétidine et de la ranitidine. A propos d'un cas.

The incidence of neuropsychiatric complications is very low in patients receiving conventional doses of cimetidine or ranitidine. In this case report, the same patient presented with psychiatric symptoms successively following treatment with both histamine H2-receptor antagonists, suggesting the involvement of histamine-mediated CNS modulation.

Antagonism exerted by an association of a Bacteroides thetaiotaomicron strain and a Fusobacterium necrogenes strain against Clostridium perfringens in gnotobiotic mice and in fecal suspensions incubated in vitro.

Antagonism between an association of Bacteroides thetaiotaomicron and Fusobacterium necrogenes strains and two strains of Clostridium perfringens was evidenced both in vivo in gnotobiotic mice and ex vivo in fecal suspensions incubated for 22 h at 37 degrees C. Several features of this antagonism were similar in and ex vivo. (i) An obligate and continuous synergy between B. thetaiotaomicron and F. necrogenes was required; (ii) the two C. perfringens strains did not respond to the same extent to this antagonism; and (iii) expression of the antagonism was host and diet dependent. Neither diffusible nor soluble inhibitory substances were detectable in feces of gnotobiotic mice, nor could depletion of nutrients be identified as causing antagonism in both in and ex vivo experiments. Our findings support the hypothesis that a reversible bacteriostasis induced by the inhibitory strains acting together continuously, and hindering the target strain from utilizing available nutrients, was responsible for this antagonism.