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Biomedical subjects

E Bernard

Publications and source records attributed to E Bernard.

At least 145 records · Page 8Linked to original sources

Treatment of infections in patients with the acquired immunodeficiency syndrome.

The microorganisms that regularly infect patients with the acquired immunodeficiency syndrome (AIDS) have become well recognized. Most take advantage of defects in T-lymphocyte function, but others, such as Streptococcus pneumoniae and Haemophilus influenzae, take advantage of B-cell defects. Still others, such as Staphylococcus aureus and Shigella species, occur or persist for reasons that are unclear. Infections with organisms associated with hospitalization and medical procedures are also seen and should be anticipated. Among the infections taking advantage of T-cell defects, Pneumocystis carinii pneumonia is the most commonly diagnosed, but cytomegalovirus infection may be equally common. Disseminated Mycobacterium avium-intracellulare infection has been found in one half of our patients at postmortem examination. The retrovirus responsible for AIDS commonly infects the central nervous system, as does Toxoplasma gondii. Although candida infections are common, dissemination is uncommon. Many of the infections respond to appropriate therapy but tend to recur when treatment is stopped. Often treatment courses must be prolonged even beyond those used in other immunocompromised hosts.

Acquired Immunodeficiency Syndrome↗

[Spinal hydatidosis treated by albendazole. A propos of 2 cases].

Two patients with hydatid cysts of the spine were given albendazole. One patient had previously been treated by surgery followed by flubendazole. Albendazole was well tolerated in both cases. Follow-up evaluations included clinical, roentgenological, serological and, in one case, histological investigations. Albendazole sulfoxide levels were assayed in plasma samples from one patient and in non-diseased bone in the other. The treatment seems to have been effective in both patients, suggesting that albendazole may be of value in hydatid disease of the bone. Confirmatory evidence from a larger series is needed.

Adult↗

[Monitoring of treatment involving 5-fluorocytosine].

The occurrence of hematologic and neurologic complications probably caused by an overdose of 5-FC has prompted us to study 5-FC pharmacokinetics in 10 patients under a 5-FC and amphotericin B. On the basis of our findings we have determined the optimal dosage that achieves desired concentrations. In 5 cases this dosages was found to differ from that suggested by the manufacturer. 5-FC concentrations were however higher than predicted levels as a result of the association with amphotericin B. A subsequent modification of dosage was needed in 10 patients. 5 undesirable side effects were recorded: thrombopenia (1 case), neutropenia (1 case), diarrhea (2 cases), and isolated rise in transaminases. In 4 patients with high 5-FC concentrations, chromatograms showed a peak possibly formed by 5-FU, suggesting that 5-FC may be converted into 5-FU.

Amphotericin B↗

[Pseudotumoral form of hepatic tuberculosis. Apropos of a case report].

Concerning one case of autonomous hepatic tuberculosis in a pseudo-tumoral aspect, the difficulties of making the diagnosis are brought to light. Liver biopsy is the best examination to clarify things, either performed under ultrasonic control or during surgery. This biopsy permits pathologic examination and culture of a liver fragment in Lowenstein medium. But in fact, only isolation of the tubercle bacillus at the liver level confirms presence of tuberculosis.

Aged↗

[Evaluation of the use of rifampin combinations in severe staphylococcal infections. Apropos of the selection of 7 resistant mutants].

Selection of rifampicin-resistant Staphylococcus aureus has been described in vitro and in vivo when this compound is given as monotherapy or orally. That this occurrence may be prevented by combination antibiotic therapy is generally accepted. We report 25 cases of severe staphylococcal infection treated by a synergistic association of rifampicin with an aminoglycoside, vancomycin, or a macrolide. Therapy failed as a result of selection of the same rifampicin-resistant Staphylococcus aureus (serotype and lysotype) in seven cases. This finding may be explained by insufficient diffusion or inactivation of the other antibiotic in the infection site.

Adolescent↗

[Bone levels of dibekacin].

Levels of an aminoglycoside, dibekacin, are studied in bone. Fifteen specimens were obtained by Tanzer trocar biopsy three hours after the ninth injection of dibekacin (1 mg/kg). Separation of cortical and spongy bone was not feasible owing to the small weight of specimens. Dibekacin concentrations were determined by microbiological assay. These concentrations were evaluated using a reference range in bone tissue determined with the same method and must be corrected according to blood levels. Dibekacin levels were 0.22 +/- 0.10 mg/l in healthy, non- contaminated specimens, and 1.70 and 1.80 mg/l in infected bone tissue.

Bacterial Infections↗

[Selection of mutant rifampin-resistant Staphylococcus aureus during the therapeutic use of this antibiotic in combinations. 3 cases].

Selection of rifampicin-resistant Staphylococcus aureus has been described in vitro and in vivo when this compound is given as monotherapy or orally. That this occurrence may be prevented by combination-antibiotic therapy is generally accepted. We report three cases of serious staphylococcal infection treated by a synergic association of rifampicin with either an aminoglycoside or vancomycin. Therapy failed as a result of selection of the same rifampicin-resistant Staphylococcus aureus (serotype and lysotype). These observations may be explained by insufficient diffusion or inactivation of the other antibiotic in the infection site.

Adult↗

[The Orf nodule].

Human Orf disease is an exceptional dermatologic benign condition, due to a Parapox virus. In sheep and goats this infection is termed "Ecthyma Contagiosum". Human beings are contaminated from infected animals. We report three cases of Orf disease in the same family. Typical viral particles have been identified in the skin of one of these patients by electronic microscopy but cultures failed to recover the pathogen. A complete study of the literature allows us to review current knowledge on this disease with which practitioners are unfamiliar.

Adolescent↗

Abolition of the thermotropic transition of charged phospholipids induced by a cardiotoxin from Naja mossambica mossambica as detected by fluorescence polarization, differential scanning calorimetry, and Raman spectroscopy.

The effects of a Naja mossambica mossambica cardiotoxin on the thermotropic properties of charged phospholipids have been studied by fluorescence polarization, differential scanning calorimetry, and Raman spectroscopy. The binding of the toxin is only governed by the net charge at the interface and is not affected by the polar head group structure of the phospholipids or by the acyl chains physical state, degree of insaturation, or length. The effect of the toxin on the phospholipid structure is drastic. In all cases, the gel to liquid-crystalline phase transition monitored by fluorescence and Raman spectroscopies is progressively abolished without notable shift in temperature as the proportion of toxin is increased. The endothermic peaks detected by differential scanning calorimetry decrease in intensity as the toxin content is increased but always remain sharp. All the techniques used give complementary results, and none of them reveals the presence of secondary transitions at higher or lower temperatures. We thus believe that the lipid molecules that are perturbed by the toxin, approximately 10 +/- 2 molecules, do not undergo a phase transition. Raman results demonstrate that these "boundary" lipids display a population of gauche rotamers that is as high as the one found in the liquid-crystalline phase of the pure phospholipid and this even well below the phase transition temperature. On the other hand, fluorescence results are interpreted as due to a partial immobilization of the lipids in contact with the toxin above the transition temperature. Thus, even though the interaction is governed by electrostatic forces, the toxin penetrates at least partially into the bilayers, inducing a disorganization of the aliphatic chains and changes in their mobility; this could explain their lytic activity.

Animals↗

[Efficacy and tolerability of acyclovir in immunosuppressed patients with herpes simplex, herpes zoster or cutaneomucous chicken-pox. Multicenter trial apropos of 50 cases].

A multicenter trial of Acyclovir was carried out in 50 immunodepressed patients. The dose used was 15 mg/kg/day for 5 days in herpes simplex and 30 mg/kg/day for 10 days in herpes zoster and chicken pox by three one-hourly intravenous infusion per day. Acyclovir had a clear cut effect in 42 cases, a partial effect in 1 case, no effect in 1 case, and its action could not be assessed in 6 cases. The cutaneous and mucous membrane lesions were stabilised after an average of two days' treatment, and regression was observed from the third day. Of the 21 cases of zoster, 15 were cured without sequellae and 5 with post-zoster pain. The treatment failed in one patient. Of the 21 cases of cutaneous and/or mucous membrane herpes simplex, 20 satisfactory and 1 partial result were obtained. The outcomes of the 2 cases of chicken pox were favourable. There were three relapses after the end of therapy (2 herpes simplex, 1 zoster) but their outcomes were favourable after a second course of Acyclovir. In 20 cases it was possible to maintain the immuno-suppressive therapy. General tolerance was satisfactory.

Acyclovir↗

Sustained elevation of hippocampal cyclic 3'-5' adenosine monophosphate levels after medial septal lesions.

The cyclic 3'-5' adenosine monophosphate (cyclic AMP) content of the rat hippocampal formation doubles during the week following a medial septal lesion and remains elevated for at least 1 month, the longest time period studied. This elevation in cyclic AMP does not result from sympathetic ingrowth, as neither superior cervical ganglion stimulation nor ganglionectomy influences hippocampal cyclic AMP content after lesions. Interruption of the cholinergic septohippocampal pathway in the fornix did not elevate hippocampal cyclic AMP content. Further, treatment of septal-lesioned animals with oxotremorine or of normal animals with atropine did not influence hippocampal cyclic AMP content. Finally, neither locus ceruleus lesions nor treatment with propranolol affected hippocampal cyclic AMP content. We believe this to be the first report of a sustained elevation in hippocampal cyclic AMP content. Like other long-term events, it is likely to have profound effects on hippocampal function and represents a remarkable brain adaptation to remote injury.

Animals↗

[Lymphocytotoxic antibodies in malaria].

We applied the microlymphocytotoxicity method to the detection of lymphocytotoxic antibodies in case of 37 patients with acute malaria or 61 patients who sojourned in endemic malaria area and presented antibodies against plasmodial antigens (indirect immunofluorescence test greater than or equal to 1/20). Lymphocytotoxic antibodies were found in 16 patients of the first group and their occurrence may explain the lymphopenia and to a lesser extent the neutropenia and thrombopenia observed in some cases. In the second group lymphocytotoxic antibodies were present in 9 cases. In all samples no anti-HLA specificity was evidenced. Four patients were submitted to auto-cross-match test and 3 were found positive suggesting that among these antibodies some are auto-antibodies with anti-lymphocyte specificity.

Antilymphocyte Serum↗

Phase separation induced by melittin in negatively-charged phospholipid bilayers as detected by fluorescence polarization and differential scanning calorimetry.

Interactions between melittin and a variety of negatively-charged lipid bilayers have been investigated by intrinsic fluorescence, fluorescence polarization of 1,6-diphenylhexatriene and differential scanning calorimetry. (1) Intrinsic fluorescence of the single tryptophan residue of melittin shows that binding of this peptide to negatively-charged phospholipids is directly related to the surface charge density, but is unaffected by the physical rate of lipids, fluid or gel, single-shell vesicles or unsonicated dispersions. (2) Changes in the thermotropic properties of negatively-charged lipids upon melittin binding allow to differentiate two groups of lipids: (i) A progressive disappearance of the transition, without any shift in temperature, is observed with monoacid C14 lipids such as dimyristoylphosphatidylglycerol and -serine (group 1). (ii) With a second group of lipids (group 2), a transition occurs even at melittin saturation, and two transitions are detected at intermediate melittin content, one corresponding to remaining unperturbed lipids, the other shifted downward by 10-20 degrees C. This second group of lipids is constituted by monoacid C16 lipids, dipalmitoylphosphatidylglycerol and -serine. Phosphatidic acids also enter this classification, but it is the net charge of the phosphate group which allows to discriminate: singly charged phosphatidic acids belong to group 2, whereas totally ionized ones behave like group 1 lipids, whatever the chain length. (3) It is concluded that melittin induces phase separations between unperturbed lipid regions which give a transition at the same temperature as pure lipid, and peptide rich domains in which the stoichiometry is 1 toxin per 8 phospholipids. The properties of such domains depend on the bilayer stability: in the case of C16 aliphatic chains and singly charged polar heads, the lipid-peptide domains have a transition at a lower temperature than the pure lipid. With shorter C14 chains or with two net charges by polar group, the bilayer structure is probably totally disrupted, and the new resulting phase can no longer lead to a cooperative transition.

Anions↗

Structure-function relationships for cardiotoxins interacting with phospholipids.

Four cardiotoxins (CTX I-IV) from Naja mossambica mossambica were compared for their ability to interact with phospholipid vesicles and their capacity to bind erythrocytes. It is concluded that the affinity of the toxins always increases in the order: I approximately equal to II less than III less than IV. The binding is specific for charged lipids even in lipid mixtures. Proteolytic attack of the free and lipid-bound cardiotoxin indicates that at least the first loop Leu1-Thr13 is at the lipid contact. Tryptic and synthetic peptides constitutive of this loop are shown to interact with lipids. Arg5 residue increases the affinity toward the bilayer. The Raman spectra of lipid-bound cardiotoxin indicate a secondary and tertiary structure mainly similar to that of the free toxin. On charged lipids cardiotoxins induce a decrease of the enthalpy and an increase of disorder without change in the transition temperature; at saturating amounts of toxin the transition is abolished. In binary mixtures of phosphatidylcholine and charged lipids the observed effects can be accounted by a phase separation induced by the toxin.

Amino Acid Sequence↗

Melittin-phospholipid interactions: binding of the mono- and tetrameric form of this peptide, and perturbations of the thermotropic properties of bilayers.

The binding of melittin to phospholipid bilayers and micelles depends on its quaternary structure and on the state of association of lipids. Monomeric melittin only binds to lipids above their cmc, whereas tetrameric melittin exhibits a biphasic binding; the interaction with monomeric lipids being possible without dissociation of the tetramer. In lipid excess, the bound state observed by fluorescence, polarization and ORD are always very similar. We propose the following model: the presence of a lipidic interface is necessary for the binding of monomeric melittin, while the tetramer may interact with lipid monomers without any dissociation: it might increase in size by addition of lipid molecules to form a micelle-like particle. The perturbations induced by melittin on the thermotropic behaviour of charged phospholipids are detected by calorimetry (DSC) and fluorescence polarization of DPH. For the first group of lipids, constituted of mono or divalent C14 and of divalent C16 lipids, the transitions are progressively abolished in the presence of melittin, without any shift of the temperature. For a second group of lipids, essentially constituted of monovalent C16 lipids, a cooperative transition is always observed. Moreover, at lipid to protein molar ratios higher than 8, there are two distinct well-defined transitions, at the same temperature as for pure lipid and 10 degrees C to 15 degrees C lower. All these results are interpreted by a phase separation occurring between quasi-pure lipid regions and the lipid-melittin complex. These last ones either could, or not, give rise to a phase transition, according to the cohesion of the initial bilayer. In the case of binary mixtures, there would be a phase separation between enriched phosphatidylcholine regions and negative lipid-melittin complexes.

Bee Venoms↗