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Biomedical subjects

B Dufour

Publications and source records attributed to B Dufour.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

High yield, site-specific coupling of N-terminally modified beta-lactamase to a proteolytically derived single-sulfhydryl murine Fab'.

The preparation of bispecific protein conjugates capable of performing diverse biological functions is an area of active investigation. Such conjugates are routinely prepared using techniques which employ random derivatization of lysine residues, but the overall utility of these methods is limited due to poor yields and heterogeneous conjugates. In this report we describe the development of site-specific linkage methodology for the chemical synthesis of a homogeneous enzyme-antibody Fab' conjugate with coupling efficiencies of at least 72%. The N-terminal threonine residue of beta-lactamase from the P99 strain of Enterobacter cloacae was oxidized to an aldehyde functional group under mild conditions with a 5-fold molar excess of sodium periodate. The murine Fab' with a single sulfhydryl at the hinge region was generated by further digestion of the peptic Fab' fragment with lysyl endopeptidase to remove a decapeptide containing two of the three cysteine residues. Coupling of the two modified proteins was accomplished through a bifunctional coupling reagent containing meleimide and aminooxy functional groups. Synthesis of the linker is described. Yields of 1:1 enzyme-Fab' were at least three times higher than for comparable random derivatization methods. Immunoreactivity and enzymatic activity were unaffected. Biodistribution studies showed a more favorable tumor to blood ratio with the site-specifically linked conjugate.

Amino Acid Sequence↗
PubMedDate not supplied

Epidemiological surveillance of infectious diseases in France.

Epidemiological surveillance, namely the continuous monitoring of diseases and health determinants in a population, has developed over the past fifteen years, in the sphere of human health as well as in animal health. All epidemiological surveillance networks include the following four stages: data collection, data transmission, data processing and dissemination of information. However, despite this basic similarity, the very many networks existing in France are extremely varied in nature. At the national level, the bodies involved in epidemiological surveillance for infectious animal diseases are the Direction générale de l'alimentation, the Agence française de sécurité sanitaire des aliments and, to a lesser degree, the Institut français de recherche pour l'exploitation de la mer. In the field, the networks rely on the Direction des services vétérinaires, veterinary practitioners, laboratories in each département, and livestock producers' groups (especially animal health protection groups). Some twenty French networks currently in operation are presented in this article according to a classification based on published criteria. In the case of human infectious diseases, epidemiological surveillance is carried out almost entirely by the Direction générale de la santé and the Directions départementales d'action sanitaire et sociale, the Institut de veille sanitaire and the various Centres nationaux de référence (CNRs). Most human infectious diseases are monitored by one or more of the following broad categories of networks: reporting of notifiable diseases, the CNRs, the network of sentinel doctors, the network of hospital laboratories and departments, and medical causes of death. An example where surveillance is covered by several networks is also presented, namely surveillance for salmonellosis and Salmonella. Lastly, methods for evaluating networks are discussed.

Animals↗
PubMedDate not supplied

Proposed criteria to determine whether a territory is free of a given animal disease.

This text describes the general principles underlying the concept of disease-free territory and the required statistical basis for the corresponding epidemiological surveillance operations. Among the essential points, it is emphasised that "disease-free" status should be given only under conditions substantiating the absence of infection (or infestation) and not simply on basis of a known low level of infection (or infestation). This manuscript also raises concerns about possible confusion that has arisen between the inevitable requirement to set a threshold on the level of detection of epidemiological surveillance tools, for economic reasons, and the acceptance of a level of infection (or infestation) that is known, but occurring below the accepted threshold, when according the official status of "territory-free from a given disease". In such a situation, it would be preferable to accord the status of "territory where the disease is in the process of eradication".

Animal Diseases↗
PubMedDate not supplied

Technical and economic evaluation method for use in improving infectious animal disease surveillance networks.

With hope of improving the increasing number of epidemiological surveillance networks for animal diseases set up in recent years, a qualitative and quantitative technical and economic evaluation tool was developed and then applied to three epidemiological surveillance networks: RENESA (a French surveillance network for salmonella and mycoplasma contamination in poultry production units subject to official sanitary controls), the French Foot and Mouth Disease Epidemiovigilance Network and REPIMAT (the epidemiological surveillance network in Chad for major cattle diseases). We identified critical points in epidemiological surveillance networks using a modified version of the hazard analysis: critical control point (HACCP) method. An evaluation grid was then developed and validated by experts who were consulted in accordance with the Delphi method. A questionnaire to collect the information required for the evaluation and a scoring guide were then designed. Our evaluation procedure also included a calculation of the annual operating costs for two of the three networks studied. On the basis of the detailed results of the technical and economic evaluation, we formulated specific suggestions for improving the networks. The cost of implementing these proposals was calculated. We then simulated the effects of implementing each of the proposed improvements and a new global evaluation score was determined for each network. The 'cost per point' of each improvement was then calculated and discussed. This tool for the technical and economic evaluation of epidemiological surveillance networks for animal diseases is proposed so that it may be tested on a far wider scale and eventually be used in improving the functioning of such networks and for risk analysis in international trade.

Animals↗
PubMedDate not supplied

[Ectopic opening of the ureter in the urethra in adult women. Radiological diagnosis apropos of 17 sites].

PURPOSE: To study diagnostic problems encountered by physicians and radiologists in adult females with ureteral ectopia into the urethra. CASE MATERIAL AND METHODS: Retrospective study of 17 localizations in 16 women, 15 to 65 years of age at the time of the definitive diagnosis of duplication of the ipsilateral urinary tract, the ectopia being connected to the upper pelvicalyceal system. RESULTS: Radiological confirmation of the diagnosis had been obtained in 14 cases. The ectopic ureter was thin in 11 cases. In 5 of 6 cases with megaureter, the distension involved only the distal intrapelvic part of the ureter. The ectopic meatus was juxta-cervical in 5 cases, much lower in the other cases. Of the 11 cases investigated by intravenous urography, 8 exhibited severe monocalyceal hydronephrosis of the upper pelvis whereas 6 upper pelvicalyceal systems were dysplastic. The lower pelvicalyceal system was congenitally normal in all cases. CONCLUSION: Most of the false negative diagnoses of intra-urethral ectopic ureter in adult female result from technically inadequate permicturating urethrocystography. The diagnosis should be evoked, especially in women with recurrent cystitis, on the urographic association of: duplication of the upper urinary tract, dysplastic or chronically distended atrophied upper pelvicalyceal system, pseudo-normal architecture of the lower pelvicalyceal system because of the unusually developed "upper" calyx.

Adolescent↗