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Biomedical subjects

M Blanchard

Publications and source records attributed to M Blanchard.

At least 19 recordsLinked to original sources
PubMed2001

Genome sequence of the plant pathogen and biotechnology agent Agrobacterium tumefaciens C58.

Agrobacterium tumefaciens is a plant pathogen capable of transferring a defined segment of DNA to a host plant, generating a gall tumor. Replacing the transferred tumor-inducing genes with exogenous DNA allows the introduction of any desired gene into the plant. Thus, A. tumefaciens has been critical for the development of modern plant genetics and agricultural biotechnology. Here we describe the genome of A. tumefaciens strain C58, which has an unusual structure consisting of one circular and one linear chromosome. We discuss genome architecture and evolution and additional genes potentially involved in virulence and metabolic parasitism of host plants.

Agrobacterium tumefaciens↗
PubMed2001

Origin and distribution of polyaromatic hydrocarbons and polychlorobiphenyls in urban effluents to wastewater treatment plants of the Paris area (France).

Polyaromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs), were investigated in urban effluents to wastewater treatment plants in the Paris area (France), under different meteorological conditions. The Achères plant was considered with special attention because of its particular features. Wastewater PAH concentration level was 6 fold higher than that of PCBs. In March, PCB concentrations did not vary whatever the meteorological conditions whereas, for PAHs, they were markedly higher during rainy episodes. In September, concentrations of both pollutants increased due to rainy weather. The rise was 30 fold stronger for PAHs. Daily fluxes displayed the same trends. This suggests that the contribution of atmospheric wet deposition to wastewater contamination prevails for PCBs. In contrast, PAHs appeared to originate mainly from urban runoff processes.

Cities↗
PubMed2001

Measuring the built environment: validity of a site survey instrument for use in urban settings.

There are few reliable measures of place with which to study the effects of socio-economic context on health. We report on the development and inter-rater reliability of a 27-item observer-rated built environment site survey checklist (BESSC). Across eleven 'housing areas' (defined as areas of homogeneity in housing form) and two raters, kappa coefficients were > or =0.5 for fifteen categorical items, and intra-class correlation coefficients exceeded 0.6 for a further three continuous measures. Ratings on several BESSC items were associated to a statistically significant degree with the prevalence of depression and residents' dissatisfaction with 'their area as a place to live'. BESSC items may prove to be valuable descriptors of the urban built environment in future studies.

Cohort Studies↗
PubMed2000

Polyamine triggering of exocytosis in Paramecium involves an extracellular Ca(2+)/(polyvalent cation)-sensing receptor, subplasmalemmal Ca-store mobilization and store-operated Ca(2+)-influx via unspecific cation channels.

The polyamine secretagogue, aminoethyldextran (AED), causes a cortical [Ca(2+)] transient in Paramecium cells, as analyzed by fluorochrome imaging. Our most essential findings are: (i) Cortical Ca(2+) signals also occur when AED is applied in presence of the fast Ca(2+) chelator, BAPTA. (ii) Extracellular La(3+) application causes within seconds a rapid, reversible fluorescence signal whose reversibility can be attributed to a physiological [Ca(2+)](i) transient (while injected La(3+) causes a sustained fluorescence signal). (iii) Simply increasing [Ca(2+)](o) causes a similar rapid, short-lived [Ca(2+)](i) transient. All these phenomena, (i-iii), are compatible with activation of an extracellular "Ca(2+)/(polyvalent cation)-sensing receptor" known from some higher eukaryotic systems, where this sensor (responding to Ca(2+), La(3+) and some multiply charged cations) is linked to cortical calcium stores which, thus, are activated. In Paramecium, such subplasmalemmal stores ("alveolar sacs") are physically linked to the cell membrane and they can also be activated by the Ca(2+) releasing agent, 4-chloro-m-cresol, just like in Sarcoplasmic Reticulum. Since this drug causes a cortical Ca(2+) signal also in absence of Ca(2+)(o) we largely exclude a "Ca(2+)-induced Ca(2+) release" (CICR) mechanism. Our finding of increased cortical Ca(2+) signals after store depletion and re-addition of extracellular Ca(2+) can be explained by a "store-operated Ca(2+) influx" (SOC), i.e., a Ca(2+) influx superimposing store activation. AED stimulation in presence of Mn(2+)(o) causes fluorescence quenching in Fura-2 loaded cells, indicating involvement of unspecific cation channels. Such channels, known to occur in Paramecium, share some general characteristics of SOC-type Ca(2+) influx channels. In conclusion, we assume the following sequence of events during AED stimulated exocytosis: (i) activation of an extracellular Ca(2+)/polyamine-sensing receptor, (ii) release of Ca(2+) from subplasmalemmal stores, (iii) and Ca(2+) influx via unspecific cation channels. All three steps are required to produce a steep cortical [Ca(2+)] signal increase to a level required for full exocytosis activation. In addition, we show formation of [Ca(2+)] microdomains (</=0.5 microm, </=33 msec) upon stimulation.

Animals↗
PubMed1999

PCB and PAH impacts on cytochrome P-450-dependent oxidases in roach (Rutilus rutilus) from the Seine River (France).

Roach were sampled in the Seine River along a gradient of polyaromatic hydrocarbon (PAH) concentrations at three stations: Marnay upstream of Paris and Epinay and Poses downstream of Paris. Two hepatic monooxygenase activities: EROD (ethoxyresorufine-O-deethylase) and AE (aldrin epoxydase) and muscle residues of PCBs and PAHs were investigated during three periods of the year (before spawning, during spawning, and postspawning). Before spawning, EROD and AE activities were significantly correlated with muscle PCB levels (p </= 0.05 for both activities) and with muscle PAH levels (p </= 0.05 for both activities) at the three stations. Cd was not inversely related to monooxygenase activities. During spawning, enzymatic activities remained low and were not correlated to pollutant levels. Postspawning EROD and AE activities were again significantly related to muscle PCBs (p </= 0. 05 for both activities). Thus, investigations of EROD and AE activities may be considered as a reliable tool for biomonitoring of PCB or PAH exposure, as far as appropriate conditions are observed. http://link.springer-ny. com/link/service/journals/00244/bibs/37n2p242.html

Animals↗
PubMed1999

Using a mobile robot to study locust collision avoidance responses.

The visual systems of insects perform complex processing using remarkably compact neural circuits, yet these circuits are often studied using simplified stimuli which fail to reveal their behaviour in more complex visual environments. We address this issue by testing models of these circuits in real-world visual environments using a mobile robot. In this paper we focus on the lobula giant movement detector (LGMD) system of the locust which responds selectively to objects which approach the animal on a collision course and is thought to trigger escape behaviours. We show that a neural network model of the LGMD system shares the preference for approaching objects and detects obstacles over a range of speeds. Our results highlight aspects of the basic response properties of the biological system which have important implications for the behavioural role of the LGMD.

Animals↗
PubMed1998

Spatial and temporal variations of herbicide (triazines and phenylureas) concentrations in the catchment basin of the Marne river (France).

Triazine and phenylurea concentrations were investigated in four sub-basins of the Marne river (France) in 1992 and 1993. The peak concentrations of atrazine, simazine and isoproturon occurred between March and July. In the four basins, the peaks were in relation with the herbicide application periods and with the important rainfalls, except for the isoproturon. The peaks of terbutryne and ametryne came later in the year, due to their use for weed control on post-emergent corn. For the phenylureas, the peak concentrations were observed in March-April next to the spraying period on winter cereals. The fast transfer of those herbicides was related to their high water solubility. In all the samples, the deethylatrazine (DEA) was detected 1 month after the atrazine due to its degradation within the soils which is of minor importance as compared to its transport by surface waters and also, to interactions between the silt sheet and the stream itself. The DAR evolution showed that the atrazine residence time depends both on the run-off in the first centimetres of the soil and on the treatment periods, particularly in the Grand Morin. The Marne river contamination level was similar to that of the Mélarchez and of the Grand Morin. The minor pollution of the Orgeval was related to minor cultivated areas.

Atrazine↗
PubMed1998

Characterization of a monoclonal antibody that recognizes a lymphocyte surface antigen for the cetacean homologue to CD45R.

As part of our current efforts to develop assays and reagents to study the immune system of marine mammals, and in view of the effort currently made to develop monoclonal antibodies to cell surface proteins of lymphocyte subsets in different species, the present paper reports on the characterization of a monoclonal antibody against the homologue of CD45R on cetacean lymphocytes. The specificity of this antibody has been characterized on the basis of immunoprecipitation of the antigen it recognized, immunoperoxidase staining on cetacean lymph node and thymus sections, as well as one and two-colour flow cytometric analysis of cetacean peripheral blood mononuclear cells and single-cell suspensions of thymus, lymph node and spleen. Anticetacean CD45R (F21.H) immunoprecipitated proteins of 180, 200 and 220 x 10(3) MW, with the 180 x 10(3) MW from being predominantly expressed on T cells and the 220 x 10(3) MW form expressed predominantly on B cells and thymocytes F21.H labelled all B cells and a proportion of T cells on single-cell suspensions of spleen cells. CD45R- killer whale peripheral blood lymphocytes expressed a higher density of CD2 than CD45R+, a characteristic of memory T cells. Killer whale T lymphocytes also lost the expression of CD45R upon activation with concanavalin A (Con A) and phytohaemagglutinin (PHA). This is the first report of a monoclonal antibody to CD45R in cetaceans, and this antibody is foreseen as a possible valuable diagnostic and research tool to assess immune functions of captive and wild cetaceans as part of the evaluation of their health status.

Animals↗
PubMed1997

Is there a specific trauma precipitating anorexia nervosa?

BACKGROUND: The aims of this study were to explore the role of life events and difficulties in the onset of anorexia nervosa and bulimia nervosa and to find out whether events and difficulties with a specific meaning, i.e. those of a certain sexual nature, are important in the onset of anorexia nervosa. METHODS: Seventy-two patients with anorexia nervosa (AN) and 29 with bulimia nervosa (BN) were assessed with the life events and difficulties schedule (Brown & Harris, 1978), the year before onset was studied. A new dimension to measure specific meaning of life events and difficulties called 'pudicity' was developed. Subjects from two community cohorts were used as comparison groups (Brown & Harris, 1978; Andrews et al. 1990). RESULTS: Anorexic patients, bulimic patients and community controls did not differ in proportion of patients with at least one severe event; however, significantly more AN and BN patients than community controls had experienced a major difficulty. Sixty-seven per cent of anorexics and 76% of bulimia nervosa patients had either a severe event or a marked difficulty during the year before onset. In AN and BN the most common serious life stresses before onset concerned close relationships with family and friends with BN patients being significantly more often than AN patients directly involved in the problem (interpersonal events). Patients with anorexia nervosa had significantly more pudicity events before onset than BN patients or community controls. CONCLUSION: While serious life stresses commonly precede the onset of anorexia nervosa and bulimia nervosa, problems with sexuality seem to be specific in triggering the onset of anorexia nervosa.

Adolescent↗
PubMed1996

Partition of metallic and organochlorinated pollutants and monoorthosubstituted PCB pattern in the trophic web from different areas of the river Seine.

The partition of metals and organochlorines was studied along the trophic web at two different pollution level areas of the river Seine. The metal results along the trophic web were: (1) High concentration processes by the sediment (Kb from 0.7 x 10(2) to 32 x 10(2) according to metal). (2) Bioconcentration processes by the plants from the water and the sediment for all metals (Kb from 0.5 10(3) to 13.2 x 10(3)); (3) The mussel (benthic and fossorial) exhibited the highest metal levels; (4) the bream (benthic and detritivorous) had higher metal levels than the roach and the perch. No biomagnification was shown for the metals along the trophic web. The organochlorine results were: (1) High concentration in the sediment with Kb-values about 10(3). (2) A relationship between lipid and PCB levels in plants. (3) No rise in organochlorines along the trophic web at the slightly polluted areas. (4) Occurrence of organochlorine biomagnification in the highly polluted area. For the PCB pattern: (1) The profiles are similar in plants and the water. (2) Sediment and animals exhibited a rise in the more chlorinated congeners accompanied by an impoverishment of the less chlorinated and monoorthosubstituted ones with rising position in the trophic web.

Animals↗
PubMed1994

Community psychiatric nurses for the elderly: well tolerated, few side-effects and effective in the treatment of depression.

Depression in elderly people is a common yet treatable psychiatric problem. The Gospel Oak depression study researched this much overlooked group and has shown that a community psychiatric nurse (CPN) was able significantly to improve the mental state of depressed elderly people. A multifaceted package of care was co-ordinated and delivered by one CPN over a study period of 3 months. A detailed account is given of those interventions implemented, highlighting those which were of most benefit for the patient. Outcome was assessed independently and it was found that those patients allocated to CPN care improved significantly compared to the non-intervention control group. Ways in which nurses can enhance care given to patients in the community are discussed.

Age Factors↗
PubMed1994

[Surgical therapy of ulcus cruris. Significance of extension of the damage to deep veins for incidence of ulcus cruris recurrence].

2 retrospective studies illustrate the importance of the extent of damage to the deep venous system governing the recurrence rate of stasis ulcers treated surgically. 1. In patients with recurrent venous stasis ulcerations associated with superficial varicosis of the great or lesser saphenous veins and incompetent perforators operative treatment of the varicose veins resulted in a 100% long-term healing rate of the ulcerations (5-year results). This was the case for 25 legs with venous ulcers in 229 consecutive cases operated for varicose veins. 2. In 76 patients with rebellious ulcers presenting without operable superficial varicose veins the treatment was a localized one consisting of wide and deep excision of the ulcer with ligature of underlying perforators and surrounding varicose veins. The 2-year success rate was 87% in 39 patients with intact deep veins, but only 59% in 37 patients with postphebite damage to the deep veins (p < 0.05). For 1 and 2 level deep vein disease the success rate was still high at 80%, but fell to 20% if damage to the deep veins extended to 3 or 4 levels! Thus, the degree of damage to the deep veins correlates well with the propensity to recurrence of venous ulceration following surgical treatment. Venous hypertension measured by phlebodynometry is the single most powerful predictor of success or failure of surgical treatment. Patients at risk should therefore be encouraged to wear compression stockings or hosiery to offset recurrencies.

Follow-Up Studies↗
PubMed1993

Depression in older people. Some criteria for effective treatment.

Depression at a level requiring clinical attention affects 12-15% of those over 65 in the community. Only a small minority are in contact with specialist mental health services, the majority of these depressed older patients will require detection and treatment in primary care. Although the symptoms of depression, once elicited, are similar to those of younger patients, initial presentation in older people can be misleading, and the onset and outcome of depression in this age group is closely linked with the state of current physical health and social adversity. Pharmacotherapy is effective for treatment, but both the family doctor and older patient may be reluctant to consider and persist with antidepressant medication. A controlled study is described which aims to improve the management of older patients in primary care by evaluating the role of a nurse acting as case manager to work in conjunction with family doctors and community agencies to implement a plan of treatment for depression. Preliminary results indicate that the nurse was effective through her personal work with depressed older patients, despite the fact that the recommended introduction of antidepressant medication was often not possible.

Aged↗