Biomedical subjects
Publications and source records attributed to T Giacomini.
During the summer 1999, four clustered cases of airport malaria were observed in France. The cases analysis revealed that airport malaria, which is a rare disease whose diagnosis is difficult, can be observed outside occupations at risk, in people livin
We have shown previously that ADP released upon platelet adhesion mediated by alphaIIb beta3 integrin triggers accumulation of phosphatidylinositol 3',4'-bisphosphate (PtdIns-3,4-P2) (Gironcel, D. , Racaud-Sultan, C., Payrastre, B., Haricot, M., Borchert, G., Kieffer, N., Breton, M., and Chap, H. (1996) FEBS Lett. 389, 253-256). ADP has also been involved in platelet spreading. Therefore, in order to study a possible role of phosphoinositide 3-kinase in platelet morphological changes following adhesion, human platelets were pretreated with specific phosphoinositide 3-kinase inhibitors LY294002 and wortmannin. Under conditions where PtdIns-3, 4-P2 synthesis was totally inhibited (25 microM LY294002 or 100 nM wortmannin), platelets adhered to the fibrinogen matrix, extended pseudopodia, but did not spread. Moreover, addition of ADP to the medium did not reverse the inhibitory effects of phosphoinositide 3-kinase inhibitors on platelet spreading. Although synthetic dipalmitoyl PtdIns-3,4-P2 and dipalmitoyl phosphatidylinositol 3',4', 5'-trisphosphate restored only partially platelet spreading, phosphatidylinositol 4',5'-bisphosphate (PtdIns-4,5-P2) was able to trigger full spreading of wortmannin-treated adherent platelets. Following 32P labeling of intact platelets, the recovery of [32P]PtdIns-4,5-P2 in anti-talin immunoprecipitates from adherent platelets was found to be decreased upon treatment by wortmannin. These results suggest that the lipid products of phosphoinositide 3-kinase are required but not sufficient for ADP-induced spreading of adherent platelets and that PtdIns-4,5-P2 could be a downstream messenger of this signaling pathway.
Though very rare compared to imported malaria, airport malaria should not be disregarded considering its very special gravity often due to late diagnosis. In most cases, it could be avoided if airlines and airports applied disinsecting measures vigilantly.
Since 1969, 63 cases of airport malaria have been reported in Western Europe, 24 of which occurred in France. Most were due to Plasmodium falciparum. In 1994, 7 cases occurred in and around Roissy Charles de Gaulle airport (CDG), showing 4 types of contamination: among employees working on airstrips or opening containers, among residents living near the airport, among people living at some distance from the airport after a secondary transport of vectors, and by vectors transported in luggage. In-flight or stop-over infection is not considered as airport malaria. The infective anophelines originated from airports where malaria transmission occurs, mostly in subsaharan Africa. A tentative list is given taking into account aerial traffic with France. Surveys in the airports of Dakar (Senegal), Cotonou (Benin), Abidjan (Cote d'Ivoire) and Yaoundé (Cameroun) found potential vectors in all of these from July to September. After 1994, the Contrôle Sanitaire aux Frontières (CSF) in charge at CDG concentrated its efforts on the flights at risk, as well as information and sensitization of airline companies, which resulted in 73% and 87% of the flights at risk being properly disinsected in 1995 and 1996. Despite pyrethroid resistance in Anopheles gambiae s.s. in West Africa, the efficacy of aircraft spraying with permethrin aerosols is still acceptable. However, surveillance of resistance should be improved and search for nonpyrethroid insecticides suitable for aircraft strongly encouraged.
Clinical and biological pitfalls that lead to incorrect or delayed diagnoses of airport malaria are described based on 7 cases reported from the Paris region in the summer of 1994. We also report the outcome and the epidemiological features of these patients.
By the ESA Biorack 'F-24 urchin' experiment of the IML-2 mission, for the first time the biomineralisation process in developing sea urchin larvae could be studied under real microgravity conditions. The main objectives were to determine whether in microgravity the process of skeleton formation does occur correctly compared to normal gravity conditions and whether larvae with differentiated skeletons do 'de-mineralise'. These objectives have been essentially achieved. Postflight studies on the recovered 'sub-normal' skeletons focused on qualitative, statistical and quantitative aspects. Clear evidence is obtained that the basic biomineralisation process does actually occur normally in microgravity. No significant differences are observed between flight and ground samples. The sub-normal skeleton architectures indicate, however, that the process of positioning of the skeletogenic cells (determining primarily shape and size of the skeleton) is particularly sensitive to modifications of environmental factors, potentially including gravity. The anatomical heterogeneity of the recovered skeletons, interpreted as long term effect of an accidental thermal shock during artificial egg fertilisation (break of climatisation at LSSF), masks possible effects of microgravity. No pronounced demineralisation appears to occur in microgravity; the magnesium component of the skeleton seems yet less stable than the calcium. On the basis of these results, a continuation of biomineralisation studies in space, with the sea urchin larva as model system, appears well justified and desirable.
During the summer 1994, six cases of airport malaria occurred in France, near the Roissy-Charles-de-Gaulle airport. Due to Plasmodium falciparum, all cases underwent rapid and severe deterioration, and in one case, the patient died. The role of laboratory tests is essential to establish the diagnosis of persons who have never resided in the endemic malaria areas and follow up with the patients already under treatment to detect possible complications.
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Two antiseptic solutions (iodine polyvidone and chlorhexidine) were compared-in a prospective non-randomized study including 294 parturient women. This study aimed to assess their efficacy against infections through epidural catheters. All catheters were subsequently cultivated. Cultures were significantly positive in 3% of cases after iodine polyvidone and 1% after chlorhexidine decontamination (not significant). No clinical or biological infections were detected. Notwithstanding some apparently unavoidable but moderate contaminations, prevention of infections post epidural analgesia depends principally on a complete adherence to asepsia rules.
We report a retrospective study of 12 caucasian men infected with HIV who had developed Mycobacterium kansasii infection (Mk). All patients had a low blood lymphocyte CD4 count (1-130, mean 15/mm3) and ten met the diagnostic criteria for AIDS. The 12 patients had pulmonary symptoms (dyspnea, cough) and fever. On chest X-ray, nodular, interstitial or diffuse parenchymal infiltrates, mediastinal and hilar adenopathies were observed. Two patients had pleural effusion, but none had cavitary lung disease. Mk was isolated by culture of sputum (n = 7), blood (n = 3), bronchial biopsy (n = 2) or bone marrow (n = 1). No patient had clinical extra-pulmonary disease. Survival after diagnosis was in average 7 months. Potential for therapeutic response is reviewed and documented.
During the very hot 1994 summer, six new cases of airport malaria have been observed in and around Roissy-Charles-de-Gaulle airport. Four patients were regular or occasional airport employees. The two other cases were inhabitants of a city at 7 km. Entomological investigations suggest that cars of airport employees served to disseminate anophelines outside the airport areas. The six cases were very severe. One patient died. Apparently, W.H.O. recommendations on aircraft disinsecting procedures have not been fully followed. There is obviously a threat for areas near the airports.
From February to September 1993, we have established the serotype of group B Streptococcus (GBS) taken from diverse microbiological samples, in particular from gastric liquids. The method utilized was a technic of coagglutination (Dako Group B Streptococcus Serotyping Test, France) allowing the search for serotypes Ia, Ib, II, III, IV and V. All in all, 169 samples have been tested: 117 vaginal samples, 17 diverse samples, 26 gastric samples, 3 placentas and 7 ammmiotic liquids. Serotypes are spread as follow: III (41), II (33), Ia (26) et V (23).... Usually, serotype III was the most frequently found and the most virulent, particularly in infections in neonates.
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Automated differential counting systems deprive laboratories of blood smear study and so malaria risks not to be diagnosed if plasmodium search is not prescribed by the physician. Some abnormalities (atypical lymphocytes called LUC and thrombopenia) can induce a blood smear. But a study of 96 patients shows that, during the first analysis, these abnormalities can miss for nearly a third of one's case. So it is very important to prescribe malaria search on blood smears when there is the least clinical symptom.
During a ten month period (march-december 1989), all streptococcal strains isolated from clinical specimens sent to our laboratory were routinely tested for high-level resistance to aminoglycosides. High-level resistance was detected in 16 out of 475 streptococci: streptomycin (two strains), kanamycin (four strains), streptomycin and kanamycin (ten strains).
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Two investigations of the prevalence of antibiotherapy and pathology due to infections have been conducted in 1978 and 1986 in a General Hospital (650 beds). In the first investigation, 29%, and, in the second one, 20% of hospitalized patients received a curative antibiotherapy. Among these patients, microbiology tests scored positive in 44% of cases in the first investigation and in 36% of cases in the second one. In the last inquiry, it was found that: the prescription was adapted to the infection in 95% of cases; the choice of antibiotic was adequate in 78% of curative treatments. Preventive antibiotherapy accounts for 30% of treatments in both investigations. In the second investigation, the prescription was adequate in 97% of cases and the length of treatment was less than 72 hours in 53% of cases. The frequency of Gram-positive cocci infections was increased while Gram-negative bacilli infections were reduced. Between the two investigations, antibiotic treatments have changed. Most noticeably, there is an increase in the number of prescriptions of macrolides, cephalosporins, nitro-imidazole derivatives and a reduction of tetracyclines, urinary antiseptics, quinolones of the 1st generation, sulfamides and penicillins. However, penicillins remain the most commonly used antibiotics family.