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Biomedical subjects

M Michel

Publications and source records attributed to M Michel.

At least 73 records · Page 4Linked to original sources
PubMed1997

Factors influencing the photo-reproduction of hydroa vacciniforme lesions.

Hydroa vacciniforme vesicles can be reproduced experimentally with repetitive UVA irradiations, but this photo-reproduction is not constant. The aim of this study was to search for the factors that influence photo-reproduction. To reproduce hydroa vacciniforme lesions six patients underwent repetitive UVA and polychromatic irradiations on the back. In four patients out of six, UVA irradiation with high doses induced papulo-vesicular lesions. Photo-induced lesions were very close to those induced by sunlight. Photo-reproduction failed when phototesting was done after or shortly before remission. Therefore, the absence of photo-reproduction appears to be a good prognostic factor.

Adolescent↗
PubMed1997

[Thrombocytopenia after cardiac surgery due to anti-platelet allo-immunization. Apropos of a case].

Thrombocytopaenia is rare after cardiac surgery but carries a very high risk of bleeding and thrombotic complications. It is generally due to heparinisation but may be secondary to the surgical procedure itself (cardiopulmonary bypass, sepsis, platelet consumption by the prosthesis), or associated factors (massive blood transfusion, drug reaction, rare antiplatelet allo-immunisation). One case of post-transfusion thrombocytopenia with antiplatelet anti-HPA-la allo-antibodies with a favourable outcome with high dose polyvalent gammaglobulins is reported. The authors describe the diagnostic and therapeutic approaches to this problem.

Aged↗
PubMed1997

[Social medicine in the ecology curriculum--Leipzig experiences with a social medicine practicum].

Apart from only offering lectures, Leipzig university introduced, within the scope of the "Ecological course", a newly outlined practical training in the field of social medicine. The topics of this practical training were: living with handicaps: chronic illness; psychosocial problems. The training consisted of two seminars and one attendance at disabled persons' unions and self-help groups. In addition to that, extern experts held lectures on the feasibility of rehabilitation. Each team, consisting of 3-5 students, was expected to write a report on their attendance in order to prove their efforts. Later on, these reports suppled the basis for discussion in the second seminar. The high quality of these reports clearly shows the students' interest in this kind of training. Some especially interested students took an active part in a final scientific colloquium, delivering their own lecture reports. Summing up, this teaching concept proved truly successful and should be continued.

Adult↗
PubMed1997

[Viral inactivation of fresh frozen plasma].

Despite the progress made in screening for blood-transmitted diseases, both the post-infection diagnostic window and the appearance of novel infective agents remain critical issues for the safety of blood transfusions. Viral inactivation methodologies for fresh-frozen-plasma (e.g., treatment with methylene blue or solvent-detergent) are currently being compared, in terms of their activities on viral subtypes and coagulation factors, as well as general toxicity and clinical effects, in order to define the advantages, residual risks and the uncertainties involved in their use.

Antiviral Agents↗
PubMed1997

[Equitest and high performance patients].

The purpose of this study was to verify whether a clinical tool used to assess balance deficits could be used to document the enhanced equilibrium skills of highly trained individuals. A sensory organization test (SOT) based on computerized dynamic posturography (Equitest Neurocom) was administered at two levels of difficulty (sway-reference gains 1.0 and 1.99) to six populations of subjects (n = 81): controls, active duty fighters pilots, former fighter pilots, windsurfers, T-kwando athletes and firemen. The more difficult SOT (gain 1.99) provided the best estimation of performances differences among the six populations. Specifically, performance scores were significantly higher (p > 0.001) for wind surfer and active duty pilots compared to the other groups. Differences between active duty are retired pilots suggest that the enhenced balance of milots is an acquired skill required continued practice. Results furthers suggest that dynamic posturography can be reliable tool for identifying subjects with enhenced equilibrium skills.

Adult↗
PubMed1996

[Fatal infectious complications in 2 patients with adult onset Still disease].

If adult Still's disease (ASD) can sometimes lead to severe destructive joint lesions and to various systemic manifestations, life-threatening complications are very rare. However, a long-term and high-dose corticosteroid therapy is often required to control the disease, with frequent corticodependence. Some authors have proposed methotrexate as a second line drug for ASD, that could permit a corticosteroid sparing effect. We report two cases of acute fatal infectious complications--legionella pneumonitis and multiple brain abscess caused by Nocardia asteroides--in two patients treated for ASD with both corticosteroids and methotrexate. These two cases raise the problem of the immunodepression induced by this combination therapy and point out the difficulties in aggressive forms of ASD.

Adult↗
PubMed1996

Electron cryo-microscopy of vitrified bulk biological specimens: ideal and real structures of water-lipid phases.

Lipid-water mixtures were studied by X-ray cryo-diffraction in order to assess the structural changes during freezing. We show that the water of aqueous lipid phases, in the concentration range of 10-30% (water weight/total weight), is vitrified by high-pressure freezing. Vitrified lipid phases can be cryo-sectioned and imaged by electron cryo-microscopy. Both the ideal or average and the real or local structures of the lipid mixtures can be studied at a resolution better than 2 nm. While the average structure of the lipid phases is in good agreement with that determined by X-ray diffraction, the local structure reveals features that might play an important role in the function of biological membranes such as in endo- and exocytosis.

Freezing↗
PubMed1996

Delayed hypersensitivity at the injection sites of a low-molecular-weight heparin.

We report a case of delayed hypersensitivity to a low-molecular-weight heparin. The patient presented with eczema at the site of subcutaneous injections and allergy tests confirmed the clinical diagnosis. There were positive tests with 3 low-molecular-weight heparins and unfractionated subcutaneous calcium heparin but negative with intravenous sodium heparin. Although delayed hypersensitivity to low-molecular-weight heparins is rare, the possibility of cross-allergy to unfractionated heparin could be a therapeutic problem for some patients.

Eczema↗
PubMed1996

Eczematous-like drug eruption induced by synergistins.

The authors report 4 cases of eczematous-like drug eruption after oral ingestion of synergistins, pristinamycin (3 cases) and virginiamycin (1 case). The lesions occurred after contact sensitization with topical virginiamycin. The clinical symptoms appeared a few hours after ingestion: a generalized maculopapular eruption, sometimes with general symptoms of anaphylactic reaction. Eczema appeared again on initial areas of contact dermatitis. There is a common allergenic group between these 2 antibiotics, which is a macrocyclic lactone. Physiopathology of this drug eruption is not clear: allergic reaction of the delayed type or anaphylactic reaction. Patients allergic to virginiamycin should be strongly cautioned against oral pristinamycin.

Adult↗
PubMed1996

Occupational contact dermatitis from propacetamol.

We report 4 cases of contact sensitization to propacetamol. They presented with lesions on the hands, forearms, crease of the elbows, and neck. They were all sensitized to multiple allergens and 2 of them were atopic. Patch tests to Pro-Dafalgan and propacetamol were positive; sodium citrate and paracetamol were negative. Our cases were similar to those published for the first time by Barbaud in 1995. The only allergen was propacetamol; patch tests with diethyglycine and paracetamol were negative. Propacetamol chlorhydrate is composed of a complex paracetamol-diethylglycine, which probably acts like a hapten capable of inducing cutaneous allergy. It is an occupational allergy affecting nurses who work in surgery departments or post-anesthesia recovery rooms, where high doses of analgesics are widely used. The patients were not allergic to oral paracetamol. Despite the usual precautions, the mixture of propacetamol chlorhydrate and solvent leaks onto the nurses' hands, suggesting that health care workers handling propacetamol chlorhydrate should wear gloves.

Acetaminophen↗
PubMed1996

Keratin 19 as a biochemical marker of skin stem cells in vivo and in vitro: keratin 19 expressing cells are differentially localized in function of anatomic sites, and their number varies with donor age and culture stage.

This study was undertaken to evaluate keratin 19 (K19) as a biochemical marker for skin stem cells in order to address some long standing questions concerning these cells in the field of cutaneous biology. We first used the well-established mouse model enabling us to identify skin stem cells as [3H]thymidine-label-retaining cells. A site directed antibody was raised against a synthetic peptide of K19. It reacted specifically with a 40 kDa protein (K19) on immunoblotting. It labelled the bulge area of the outer root sheath on mouse skin by immunohistochemistry. Double-labelling revealed that K19-positive-cells were also [3H]thymidine-label-retaining cells, suggesting that K19 is a marker for skin stem cells of hair follicles. K19-expression was then used to investigate the variation in mouse and human skin stem cells as a function of body site, donor age and culture time. K19 was expressed in the hair follicle and absent from the interfollicular epidermis at hairy sites (except for some K18 coexpressing Merkel cells). In contrast, at glabrous sites, K19-positive-cells were in deep epidermal rete ridges. K19 expressing cells also contained high levels of alpha 3 beta 1 integrin. The proportion of K19-positive-cells was greater in newborn than older foreskins. This correlated with keratinocyte culture lifespan variation with donor age. Moreover, it could explain clinical observations that children heal faster than adults. In conclusion, K19 expression in skin provides an additional tool to allow further characterization of skin stem cells under normal and pathological conditions in situ and in vitro.

3T3 Cells↗
PubMed1995

Insertion mutations at the maize Opaque2 locus induced by transposable element families Ac, En/Spm and Bg.

Eight independently isolated unstable alleles of the Opaque2 (O2) locus were analysed genetically and at the DNA level. The whole series of mutations was isolated from a maize strain carrying a wild-type O2 allele and the transposable element Activator (Ac) at the wx-m7 allele. Previous work with another unstable allele of the same series has shown that it was indeed caused by the insertion of an Ac element. Unexpectedly, the remaining eight mutations were not caused by the designated Ac element, but by other insertions that are structurally similar or identical to one of two different autonomous transposable elements. Six mutations were caused by the insertion of a transposable element of the Enhancer/Suppressor-Mutator (En/Spm) family. Two mutations were the result of the insertion of a transposable element of the Bergamo (Bg) family. Genetic tests carried out with plants carrying the unstable mutations demonstrated that all were caused by the insertion of an autonomous transposable element.

Alleles↗