PubMed Health⌕ Search

Biomedical subjects

P Colin

Publications and source records attributed to P Colin.

At least 73 records · Page 4Linked to original sources
PubMed1995

Control of Listeria monocytogenes in the delicatessen industries: the lessons of a listeriosis outbreak in France.

During a recent outbreak of foodborne listeriosis which occurred in France in 1992, investigations were carried out in order to identify the plants associated with the production of contaminated products. These investigations were made in six 'suspect' delicatessen plants following the first epidemiological investigations, and in one 'control plant'. The first visits were made during working operations. Two hundred and seventy samples were taken ('environmental' swabs, air samples, products), with 68% of the swabs being positive for Listeria monocytogenes in raw product areas, and 33% positives in the finished product area. The epidemic phagovar was identified in a single plant preparing pork tongues in aspic. The major causes of contamination identified were contact of cooked products with soiled surfaces, cross-contamination between 'raw' and 'cooked' channels and the inadequacy of cleaning and disinfection procedures. A second visit was also made to five plants to provide validation of their cleaning and disinfection procedures. Among 112 swabs collected, 17% of the samples from raw product surfaces and 7% from finished product surfaces were found to be positive. These results suggest that cleaning and disinfection procedures were unable to eliminate sources of L. monocytogenes when not correctly applied.

Disease Outbreaks↗
PubMed1995

Culture media for the isolation of campylobacters.

The history of the development of selective media for isolation of campylobacters, including the rationale for choice of selective agents is described. Developments have included modifications to allow incubation at 37 degrees C instead of 42 or 43 degrees C and changes in the types and concentrations of antibiotics in order not to inhibit organisms such as Campylobacter upsaliensis, C. jejuni subsp. doylei and some strains of C. coli and C. lari. When examining foods, plating media originally developed for isolation from faeces are normally used, sometimes after liquid enrichment. Most of the media include ingredients intended to protect campylobacters from the toxic effect of oxygen derivatives. Most commonly used are lysed or defibrinated blood; charcoal; a combination of ferrous sulphate, sodium metabisulphite and sodium pyruvate (FBP); and haemin or haematin. To date no medium includes an indicator system--for instance a pH indicator to show whether colonies produce acid or alkali from particular substrates. The manner in which liquid enrichment media are used has been modified for food samples to avoid inhibitory effects on sublethally damaged cells by toxic components in the formula. This is done by a preliminary period of incubation at reduced temperature and sometimes by delayed addition of antibiotics. Expensive and time-consuming methods have been proposed to achieve a microaerobic atmosphere while using liquid enrichment media. To date there is no generally accepted 'standard' method of isolating campylobacters from food.

Anti-Bacterial Agents↗
PubMed1995

[A little known cause of persistent fever and granulomatous hepatitis in children: cat scratch disease].

BACKGROUND: Extensive hepatic and splenic involvement in cat-scratch disease has rarely been reported. CASE REPORT: A 2 1/2 year-old boy suffered for 2 weeks from high-grade fever, abdominal pain and alteration of his general condition. Ultrasonography revealed multiple hypoechogenic nodules in liver and spleen. The CT scan also showed hypodense lesions. An open liver biopsy was performed 5 weeks after the onset of illness. Histopathology of a resected nodule demonstrated neutrophilic granulomatous inflammation with central abscess formation. Recent cat exposure, suppurated epitrochlear lymph node 15 days before admission were also consistent with cat-scratch disease which was confirmed by elevated anti-Rochalimaea antibody titers. Follow-up showed complete resolution of all hepatic and splenic lesions within 6 months and emergence of splenic calcifications. CONCLUSION: Cat-scratch disease should be considered in the diagnosis of fever of unknown origin and hepatosplenic abscesses in children.

Cat-Scratch Disease↗
PubMed1995

Transplantation to the rat brain of human neural progenitors that were genetically modified using adenoviruses.

Transplantations for neurological disorders are limited by the supply of human fetal tissue. To generate larger numbers of cells of appropriate phenotype, we investigated whether human neural progenitors expanded in vitro could be modified with recombinant adenoviruses. Strong expression of beta-galactosidase was obtained in vitro. Two or three weeks after transplantation of engineered cells to the rat brain, we observed a small percentage of surviving neuroblasts strongly expressing beta-galactosidase in four out of 13 rats. Thus human precursor cells that have been genetically modified using adenoviruses are a promising tool for ex vivo gene therapy of neurodegenerative diseases.

Adenoviridae↗
PubMed1995

Systemic cat scratch disease: hepatic and splenic involvement about 3 pediatric cases.

Numerous diseases can lead to multinodular lesions of liver and spleen; surgical biopsy can be required for the etiologic diagnosis. Among these diseases, systemic cat scratch disease has been recently described. Macroscopical appearance of the lesions is evocative and must be known by surgeons. Three children with systemic cat scratch disease involving liver and spleen are reported.

Biopsy, Needle↗
PubMed1995

Cleaning and disinfection practice in the meat industries of Europe.

The application and efficacy of cleaning and disinfection methods are reviewed, together with the relevant European and French legislation. European Commission Hygiene Directive 93/43/EEC of 14 June 1993 proposes the adoption of hazard analysis and critical control points (HACCP) for the meat industry, and this includes cleaning and disinfection. It is necessary to organise a team for washing, cleaning, rinsing, disinfection and final rinsing; three different types of organisation are compared. Application of HACCP and its contribution to the shelf life of products and their contamination with Listeria monocytogenes is discussed in the light of practical experience with poultry meat and cured pork products. Various means of verifying the efficacy of cleaning and disinfection (turbidimetry, adenosine triphosphate assay and macroscopic observation) are compared with the techniques of conventional microbiology. The authors conclude that cleaning and disinfection are essential for application of HACCP to the meat industry.

Animals↗
PubMed1995

Comparison of resistance of various poultry lines to infection by Salmonella enteritidis.

A study was undertaken to determine the susceptibility or resistance of 9 outbred experimental or commercial poultry lines to Salmonella enteritidis PT4. Young chicks were inoculated either intramuscularly or orally just after hatching. After intramuscular challenge the lines could be divided into susceptible lines (LD 50% < or = 10(2) Salmonella per animal), intermediate lines (LD 50% about 10(4) Salmonella) and resistant lines (LD 50% > 10(5) Salmonella). The results obtained after oral challenge confirmed these 3 groups for both mortality rates and the probability of the presence of salmonellae in the spleen and liver. There was no difference between lines concerning caecal carriage.

Administration, Oral↗
PubMed1995

Chemiluminescent and colorimetric enzymatic assays for the detection of PCR-amplified Salmonella sp. products in microplates.

To improve Salmonella detection, we developed nonradioactive hybridization assays of amplified products from pure Salmonella cultures. Biotin-labeled PCR products were trapped by internal probes covalently bound to CovaLink-NH MicroWells and detected by colorimetric or chemiluminescent enzymatic reactions. The sensitivities of colorimetric assays using peroxidase and alkaline phosphatase were similar to those obtained with an ethidium bromide-stained agarose gel; both procedures allow the detection of 50 Salmonella cells. Chemiluminescence was 10-fold more sensitive than colorimetry.

Alkaline Phosphatase↗
PubMed1994

Direct intracerebral gene transfer of an adenoviral vector expressing tyrosine hydroxylase in a rat model of Parkinson's disease.

Direct intracerebral gene transfer to neural cells has been demonstrated with recombinant adenovirus encoding beta-galactosidase. To explore the potential of recombinant adenovirus for the therapy of neurological disease we constructed a recombinant adenovirus encoding tyrosine hydroxylase and optimized intracerebral injection to express the gene in the striatum of unilaterally denervated rats. These animals have dopamine depletion in their lesioned striatum, causing a rotation asymmetry induced by apomorphine. One and two weeks after intracerebral injection this sensorimotor asymmetry was decreased by the adenovirus encoding tyrosine hydroxylase and not by a control adenovirus encoding beta-galactosidase. Histological analysis showed that tyrosine hydroxylase was preferentially expressed in astrocytes.

Adenoviridae↗
PubMed1994

Cell-type-specific expression and regulation of a c-fos-NGF fusion gene in neurons and astrocytes of transgenic mice.

A mouse line transgenic for nerve growth factor (NGF) was developed using the mouse prepro-NGF cDNA inserted within a plasmid containing the proximal region (-10 to -550 bp) of the c-fos promoter and the transcription termination and polyadenylation signals of the rabbit beta-globin gene. No significant modification of gross behavior or central nervous system anatomy was detected in adult animals as assessed by immunohistochemistry and in situ hybridization for NGF and choline acetyltransferase. The expression of the transgene and the possible regulation of its expression by agents acting on the promoter were investigated in vitro. Despite the presence of an additional pool of NGF mRNA specific to the transgene, basal levels of NGF in the supernatant of transgenic astrocytes were similar to normal ones. On the other hand, transgenic neurons spontaneously synthesized and released levels of NGF two to three times higher than normal neurons, while mRNA levels were barely detectable by conventional Northern blotting. The tissue-specificity of NGF expression was respected, with higher levels in hippocampal than neocortical neurons. Increases of NGF mRNA by agents acting on the promoter could be observed in normal and transgenic astrocytes only after inhibition of the protein synthesis by cycloheximide, suggesting a similar rapid turnover of normal and transgenic transcripts. Cyclic AMP agonists specifically increased the secretion of NGF protein by transgenic astrocytes and neurons, while activators of the protein kinase C had a similar effect on transgenic and normal cells. Differences between amounts of NGF secreted by neurons and astrocytes with regards to their respective content in mRNA suggest that transgenic transcripts are subject to normal cell- and tissue-specific post-transcriptional regulations. Agents acting on the c-fos promoter through the protein kinase C or cyclic AMP routes differentially increased the secretion of NGF by transgenic astrocytes or neurons, supporting this hypothesis.

Animals↗
PubMed1994

Evaluation of different DNA extraction procedures for the detection of Salmonella from chicken products by polymerase chain reaction.

Polymerase chain reaction (PCR) was used after a short pre-enrichment culture to detect Salmonella subspecies in chicken fillets. A direct PCR assay performed with chicken meat inoculated with Salmonella Typhimurium produced no PCR products. Six different DNA extraction protocols were tested to recover efficiently Salmonella DNA after a short incubation period. Three of them gave results that were reliable, rapid and sensitive. Successful protocols used Proteinase K and/or a centrifugation step to concentrate the samples. For reliable detection of Salmonella subspecies, a few thousand bacterial cells per ml must be present. To obtain this number of bacterial cells with an inoculation of about one cell in 25 g of ionized food products, it was necessary to incubate samples for at least 10 h before PCR. A larger inoculum of approximately 10 cells in 25 g of ionized food products, required 8 h in culture broth to give positive results by PCR-based assay.

Animals↗
PubMed1994

Randomized comparison of neoadjuvant cisplatin and fluorouracil infusion followed by radiation versus concomitant treatment in advanced head and neck cancer.

PURPOSE: To compare two published schedules of cisplatin plus fluorouracil (5-FU) infusion and radiation as either sequential or concomitant treatment for toxicity and efficacy in patients with unresectable head and neck cancer. PATIENTS AND METHODS: This was a randomized trial between cisplatin 100 mg/m2 over 15 minutes on day 1 plus 5-FU 1.0 g/m2 by continuous infusion on days 1 to 5, repeated every 3 weeks for three cycles, followed by 70 Gy of radiation in 7 to 8 weeks, versus cisplatin 60 mg/m2 over 15 minutes on day 1 plus 5-FU 800 mg/m2 by continuous infusion on days 1 to 5 plus radiation 2 Gy on days 1 to 5, repeated every other week for seven cycles. Unresectable head and neck squamous cancer patients not previously treated with radiation or chemotherapy and with a performance status of 0 to 2 were stratified by tumor (T) and node (N) groupings and performance status and randomized. RESULTS: Two hundred fifteen patients were entered and 214 analyzed, 107 on each arm. After all treatment, overall response rates were different (P = .003), with similar complete response rates, but more partial responses and fewer patients with no change or progression with concomitant treatment. Cox regression analysis for progression-free survival identified concomitant treatment (P = .003), Radiation Therapy Oncology Group (RTOG) stage III grouping (P < .0001), performance status (P = .0002), concomitant treatment (P = .003), and treating institution (P = .006) as significant. The sequential and concomitant treatments showed similar distant failure patterns (10% and 7%, respectively), but divergent regional failure rates (55% and 39%). Severe and worse toxic events were similar between the treatment programs, but radiation-induced mucositis combined with cisplatin-induced water-losing nephropathy, in the concomitant arm only, demanded more supportive care. Survival duration was similar between the treatment arms, but significantly more patients in the sequential arm died of their cancer (P = .011). CONCLUSION: Concomitant treatment offered improved disease control, predominantly of regional disease, but benefit was dependent on the experience of the treating institution. Translation of this benefit into improved survival is not yet evident, with an excess of deaths from other causes in the concomitant arm.

Adult↗
PubMed1992

[Esophageal cancer: did combined treatments improve prognosis?].

Prognosis of esophageal cancer is very poor. Five-year survival does not exceed 20% after radical surgery, the best available treatment. Unfortunately, only 40% of the patients are amenable to surgery because of poor general status and/or locoregional extension. Adjuvant treatment did not yield survival improvement. Preoperative radiotherapy (three randomized trials) or postoperative radiotherapy (one randomized trial) showed only a decrease of regional relapses, perhaps only for the nodes negative patients. Neoadjuvant chemotherapy obtains some interesting response rate (20-60%), but there has been no evidence yet for survival improvement. Recently, promising results were presented after combination of radiotherapy and chemotherapy. In this paper, we review the present status of combined treatment for esophageal cancer. Our multicentric group (OSOF) is now completing a phase II trial, that should soon form the basis for a phase III prospective study.

Combined Modality Therapy↗
PubMed1991

Surgical restaging of advanced Hodgkin's disease after first line chemotherapy.

47 patients with stages IIIB and IV Hodgkin's disease underwent laparotomy with splenectomy as restaging procedure after first-line chemotherapy (CT) which included 4 cycles of CT ABV/IMEP/PCAV/ABV. After surgical restaging (SR), all patients were scheduled to receive 2 additional cycles IMEP/PCAV followed by TNI 20 Gy and patients with residual clinical abnormality or positive restaging surgery received a 20 Gy boost to these areas. 11 patients (23.4%) were found to have active disease in the spleen (10 patients) and/or the lymph nodes (3 patients) after SR. In the spleen, foci of active disease had a size in millimeters and confirm the limits of clinical restaging. According to the response to CT, 5 of the 35 patients (14%) clinically restaged as good responders had active disease; 6 of the 12 patients (50%) clinically restaged as poor responders had active disease. SR is of interest in selected patients with slowly responding disease to determine the indication of an extended field RT for responding patients and salvage therapy for patients resistant to CT.

Adult↗
PubMed1990

Structural study of the yeast RNA polymerase A. Electron microscopy of lipid-bound molecules and two-dimensional crystals.

Two-dimensional crystals of yeast RNA polymerase A (I) were obtained by interaction with positively charged lipid layers. The analysis of single molecular images of lipid-bound RNA polymerases showed that the enzyme was preferentially oriented by the lipid phase, which probably facilitated crystallization. Electron micrographs of the crystals revealed a rectangular unit cell 25.8 nm by 45.6 nm in size containing four RNA polymerase dimers related by P22(1)2(1) symmetry. The projection map showed, at about 2.5 nm resolution, two different views of the enzyme characterized by two bent arms, which appeared to cross at one end. These arms are likely to contain the A190 and A135 subunits and delimit a 3 to 4 nm wide groove. Additional structural features were observed and compared to the Escherichia coli enzyme.

Lipid Bilayers↗
PubMed1990

Electron microscopic study of yeast RNA polymerase A: analysis of single molecular images.

The structural features of the yeast DNA-dependent RNA polymerase A (I) were examined by Scanning Transmission Electron Microscopy. The enzyme was absorbed in its monomeric form and negatively stained prior to digital image acquisition at low dose. The signal to noise ratio of single particle images was improved through averaging of a large number of previously aligned and partitioned images. Six classes of images were obtained reproducibly which corresponded to different projections of the enzyme. The enzyme structure was characterized by its presence of two curved arms which defined a longitudinal cleft. By analogy with the Escherichia coli enzyme, these arms could correspond to the two large subunits A135 and A190.

Chemical Phenomena↗
PubMed1990

Simple measurement of captopril in plasma by high-performance liquid chromatography with ultraviolet detection.

Captopril is an orally active inhibitor of angiotensin-converting enzyme. A rapid, accurate, and sensitive high-performance chromatography (HPLC) method is described for measuring plasma concentrations of captopril. Captopril was stabilized by forming an adduct with p-bromophenacyl bromide. This adduct was measured by HPLC using a C-18 reverse-phase column and monitoring the column effluent by ultraviolet absorption at 260 nm. The method proved to be linear in the clinical range of 10-1,000 ng/ml. The plasma levels of captopril in a young patient given a small oral dose were determined by this method.

Acetophenones↗