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Biomedical subjects

C Fortin

Publications and source records attributed to C Fortin.

At least 37 records · Page 2Linked to original sources
PubMed1992

Growth inhibition and loss of virulence in cultures of Agrobacterium tumefaciens treated with acetosyringone.

Acetosyringone, a phenolic inducer of the virulence (vir) genes of Agrobacterium tumefaciens, inhibited the growth of the nopaline-type strains T37 and C58 incubated under acidic conditions. In the course of a 6-day incubation with acetosyringone, avirulent clones were produced in different proportions by strains T37 and C58 and also by a spontaneous variant of strain C58, denominated C58F. The proportion of avirulent clones in acetosyringone-treated cultures often exceeded 50% for strains T37 and C58F and was of the order of 1% for strain C58. Control cultures not exposed to acetosyringone did not yield avirulent clones. Two other vir inducers, sinapinic acid and syringaldehyde, also inhibited growth and promoted accumulation of avirulent clones in cultures of strains C58F and T37. On the other hand, various acetosyringone analogs reported not to induce the vir genes did not act as growth inhibitors. All of the T37 and most of the C58F avirulent clones examined still carried a Ti plasmid. In all instances examined, avirulent clones still carrying a Ti plasmid were mutated in this plasmid. Mutants of strain C58F lacked the capacity to induce a virB::lacZ fusion in the presence of acetosyringone.

Acetophenones↗
PubMed1991

[Clinical and hemodynamic evaluation of cholecystectomies performed under laparoscopy].

Hundred patients who underwent laparoscopic cholecystectomy and 25 consecutive patients where multiple hemodynamic parameters were measured were included in the study. The mean operative time was 84 minutes and operative cholangiography was selective. No deaths and five major complications were reported. Months after laparoscopic cholecystectomy, two patients needed open surgery for pathology missed at initial exploration. One patient sustained minor trauma to the biliary tree. Despite generally normal vital signs and few cardiac arrhythmias, cardiac output dropped in many patients during laparoscopic cholecystectomy. This was specially marked at the end of peritoneal insufflation when the Fowler position was assumed, emphasizing the need for close anesthetic monitoring, specially during the first half hour of this procedure.

Adolescent↗
PubMed1989

In vivo biostability of four types of arterial grafts with impervious walls; their haemodynamic and pathological characteristics.

We describe the haemodynamic and pathological characteristics of four types of four impervious arterial prostheses, two alloplastic (Mitrathane and Gore-Tex), and two chemically processed bovine heterografts (Solcograft and Solco P). They were implanted in the thoracic aortae of dogs for durations of 24 hours, 48 hours, one week, two weeks, one month, three months and six months. Haemodynamic analyses showed no relation between the shear rate index, I.gamma, and compliance, CD. The observed shear rates are 6.5 times lower than those likely to damage the endothelial cell layer. Macroscopic and microscopic observations of explanted grafts showed the presence of obstructive thrombi at the anastomoses of Mitrathane grafts as early as one week. Gore-Tex grafts develop in the area of anastomoses parietal-thrombi which reorganize and become covered with pseudo-endothelial cells. The bovine heterografts show a similar behaviour. However, whereas Solcograft has an irregular thin wall, Solco P had improved characteristics except in the graft implanted for three months which demonstrated, some manufacturing weaknesses. Both types showed the development of anastomotic pannus covered with endothelial-like cells. All grafts, whether alloplastic or chemically processed, suffered from an absence of healing of the middle part of the prosthesis. The cause of this problem will be found in the analysis of the biochemical and enzymatic reactations between the material used and its physiological surrounding.

Anastomosis, Surgical↗
PubMed1989

Visual detection of microencapsulated insecticides with selective staining and scanning electron microscopy.

Selective staining with Sudan IV and methylene blue for light microscopy and scanning electron microscopy (SEM) were investigated to determine their potential for detecting and quantifying microencapsulated insecticides. Penncap-M (microencapsulated methyl parathion), Penncapthrin (microencapsulated permethrin), and Dyfonate (microencapsulated fonofos) were selectively stained with Sudan IV but not with methylene blue. Selective staining was not possible for Altosid SF-10 or SR-20 (microencapsulated methoprene) with either stain. Sudan IV enabled detection of some microencapsulated formulations in the digestive content of selected aquatic invertebrates and prepared contaminated pollen samples. Staining intensity with Sudan IV was greatest with acetone but capsular damage was high. A solvent ratio of 50:50 and 20:80 acetone/xylene minimized capsular collapse and maintained good staining intensity. The use of SEM for capsule identification and quantification depended upon the method of sample preparation: the slide smear method was superior to samples prepared by incision or microtomy. SEM was most suitable for investigation of formulations such as methoprene, for which selective staining was not possible. The chemical basis of staining with Sudan IV and potential application of both identification techniques are discussed.

Aedes↗
PubMed1987

The residual effect of temephos (Abate 4-E) on nontarget communities.

The impact of mosquito control on nontarget organisms using Abate-4-E was investigated in terms of immediate mortality and residual activity. Three 10 year old, man-made ponds having similar community structures and population densities were studied. The residual activity, determined by bioassays with 4th instar Aedes communis, was significantly longer in a relatively cooler pond. Populations of copepods and Cladocera took longer to return to control densities in that same pond. The role played by the physicochemical characteristics of the pond water as well as the intrinsic susceptibility and recovery capacity of the populations considered are discussed.

Aedes↗
PubMed1978

Pharmacokinetic interaction between amitriptyline and neuroleptics.

The influence of amitriptyline on the plasma level of various neuroleptics was studied in 25 chronic schizophrenic patients. The study lasted 20 weeks. Patients were kept first 4 weeks on their former neuroleptic medication, with amitriptyline added for 12 subsequent weeks, and withdrawn during the last 4 weeks when only the neuroleptic medication was continued unchanged. The plasma level of neuroleptics was assayed by gas-liquid chromatography, once weekly throughout the study. The amitriptyline plasma level was also evaluated once weekly during the 12 weeks of its administration. The mean neuroleptic plasma values for each 4-week period were pooled together in three groups: aliphatic, piperdine and piperazine phenothiazine derivatives. Amitriptyline provoked some increase of the plasma level of all phenothiazine derivatives. This augmentation was significant only transitorily, however. The putative mechanisms of this neuroleptic tricyclic antidepressant interaction are discussed.

Adult↗
PubMed1975

Growth hormone treatment in hypopituitary dwarfs: longitudinal psychological effects.

This is one of a series of studies on the psychological effects of medically induced growth in a group of hypopituitary dwarfs treated with Human Growth Hormone (HGH). Before treatment these dwarfs were found to be psychologically immature and hypoactive, without any manifestation of aggressive drives, and had an underlying low self-esteem when compared with the normal population. When compared with a matched group with constitutional growth delay the hypopituitary patients were found to use denial, whereas the control group used well-organized compensatory mechanisms (9). Immaturity was found in both groups. When the hypopituitary dwarfs reached adolescence they lacked the core attributes of masculinity or femininity and manifested some ambiguity or even inversion in their choice of gender role (10). This report deals with their psychological evolution in relation to physical growth.

Adolescent↗