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Biomedical subjects

C Boucher

Publications and source records attributed to C Boucher.

At least 55 records · Page 3Linked to original sources
PubMed1995

The hrp gene locus of Pseudomonas solanacearum, which controls the production of a type III secretion system, encodes eight proteins related to components of the bacterial flagellar biogenesis complex.

Five transcription units of the Pseudomonas solanacearum hrp gene cluster are required for the secretion of the HR-inducing PopA1 protein. The nucleotide sequences of two of these, units 1 and 3, have been reported. Here, we present the nucleotide sequence of the three other transcription units, units 2, 4 and 7, which are together predicted to code for 15 hrp genes. This brings the total number of Hrp proteins encoded by these five transcription units to 20, including HrpB, the positive regulatory protein, and HpaP, which is apparently not required for plant interactions. Among the 18 other proteins, eight belong to protein families regrouping proteins involved in type III secretion pathways in animal and plant bacterial pathogens and in flagellum biogenesis, while two are related solely to proteins involved in secretion systems. For the various proteins found to be related to P. solanacearum Hrp proteins, those in plant-pathogenic bacteria include proteins encoded by hrp genes. For Hrp-related proteins of animal pathogens, those encoded by the spa and mxi genes of Shigella flexneri and of Salmonella typhimurium and by the ysc genes of Yersinia are involved in type III secretion pathways. Proteins involved in flagellum biogenesis, which are related to Hrp proteins of P. solancearum, include proteins encoded by fli and flh genes of S. typhimurium, Bacillus subtilis and Escherichia coli and by mop genes of Erwinia carotovora. P. solanacearum Hrp proteins were also found to be related to proteins of Rhizobium fredii involved in nodulation specificity.

Amino Acid Sequence↗
PubMed1995

Triplet repeats in neuromuscular disorders.

SBMA, SCA1 and DM are all neuromuscular disorders which have very different presentation with varying degrees of severity but with a common feature of muscular weakness. In addition they all show anticipation correlating with the length of an unstable trinucleotide repeat. It is possible that trinucleotide repeat expansions will underlie other hereditary neuromuscular disorders, for example spinocerebellar ataxia type 2 (mapped to 12q and with similar symptoms to SCA1 including anticipation) is a prime candidate (30). The biochemical effects of these expansions have not yet been elucidated and therefore effective therapeutic interventions cannot currently be designed for affected individuals. However, the relative ease of diagnosis and the availability of accurate prenatal testing have already had a significant impact on the patient groups.

Female↗
PubMed1994

Relation between coronary artery stenosis assessed by visual, caliper, and computer methods and exercise capacity in patients with single-vessel coronary artery disease. The Veterans Affairs ACME Investigators.

BACKGROUND: Practitioners often assume a close relation between angiographic coronary artery stenosis and patient functional capacity. To test this unproven hypothesis, we analyzed the relation between coronary artery stenosis measured by different methods and maximal treadmill exercise tolerance in patients with single-vessel disease before and after intervention by percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: Coronary angiography and maximal exercise testing off anti-ischemic medication were performed before random assignment of 227 patients with single-vessel coronary artery disease to PTCA or drug therapy. Six months later, angiography and exercise testing were repeated with patients assigned to PTCA off anti-ischemic therapy so that the altered coronary stenosis was the only consistent variable. Patients assigned to drug therapy were exercised on drug therapy. Coronary stenosis was assessed visually by the local investigator and quantitatively by blinded caliper and computer methods in central laboratories. Variabilities of caliper and computer measurements were established in a subset read twice. Visually estimated stenosis > or = 90% at baseline was associated with shorter exercise duration (7.9 versus 9.2 minutes, P < .04). Similar segregation at baseline was not observed with caliper or computer methods. Regardless of the method of measurement used, correlation between changes of lesion severity and exercise duration from baseline to follow-up was poor. Patients were angiographically classified as "better," "unchanged," or "worse" if follow-up stenosis was below, within, or above 2 SD of mean technical variability from baseline (+/- 18.8%, caliper, +/- 14.6%, computer). Exercise duration for PTCA patients improved among those with better lesions (+2.4 minutes, n = 50, P = .001) but also among those with unchanged lesions (+1.9 minutes, n = 41, P < or = .001). Unchanged medically treated patients improved less (+0.5 minutes, n = 86, P = .04). Results were similar when patients were angiographically classified by minimum lumen diameter. CONCLUSIONS: Handheld calipers and quantitative coronary angiography are equivalent techniques for making anatomic measurements. Neither method identified patients having reduced exercise capacity at baseline as well as visual estimation. The relation between changes of coronary stenosis and exercise duration is highly variable, at least in part because of the insensitivity of angiographic methods for detecting small but potentially important changes. Minimal anatomic improvement 6 months after PTCA does not preclude a good functional outcome. Contrary to common belief, angiographic stenosis does not correlate well with functional capacity, even in patients with single-vessel disease.

Angioplasty, Balloon, Coronary↗
PubMed1994

[Deinstitutionalization of severely mentally retarded patients: impact on prescription of neuroleptics].

The neuroleptic medication prescribed over a period of 12 years for three groups of severely developmentally handicapped patients is analyzed retrospectively. The average daily doses prescribed for two groups of patients, deinstitutionalized either to foster homes or group homes, are compared to those prescribed for a third group of patients who were not deinstitutionalized. The results show that deinstitutionalization had no impact on the prescribing of neuroleptics, regardless of the type of residence: group home or foster home. The results show, moreover, that for the three groups of patients, time spent without medication decreased significantly over the 12 years of this study. These results are discussed in relation to the problem of the patients' social reintegration into the community.

Adult↗
PubMed1993

Conservation of secretion pathways for pathogenicity determinants of plant and animal bacteria.

Extracellular proteins of plant and animal bacteria are important in virulence. Many of these are secreted through the type I sec-independent and the type II sec-dependent pathways. Recently, a third distinct pathway, involved in secretion of Yops, has been discovered in Yersinia. This pathway has homology with pathways in plant pathogenic bacteria that are putatively involved in the secretion of proteins active on plant cells, such as harpin and possibly some avr gene products

Animals↗
PubMed1993

The same mutation that encodes low-level human immunodeficiency virus type 1 resistance to 2',3'-dideoxyinosine and 2',3'-dideoxycytidine confers high-level resistance to the (-) enantiomer of 2',3'-dideoxy-3'-thiacytidine.

Variants of human immunodeficiency virus type 1 that display 500- to 1,000-fold resistance to the (-) enantiomer of 2'-deoxy-3'-thiacytidine and approximately 4- to 8-fold resistance to 2',3'-dideoxycytidine and 2',3'-dideoxyinosine have been generated through in vitro selection with the former compound. The polymerase regions of several of these resistant viruses shared a codon alteration at site 184 (ATG-->GTG; methionine-->valine), a mutation previously associated with low-level resistance to 2',3'-dideoxycytidine. The biological relevance of this mutation for the (-) enantiomer of 2'-deoxy-3'-thiacytidine was confirmed by site-directed mutagenesis with the HXB2-D clone of human immunodeficiency virus type 1.

Antiviral Agents↗
PubMed1992

Sleep disorders in early childhood: association with insecure maternal attachment.

Psychological, family, and social characteristics relating to attachment relationships were measured in mothers of 20 sleep-disordered toddlers, comparing them with 21 mothers of toddlers without sleep problems. The groups were matched on measures of socioeconomic status, child and maternal age, maternal education, marital status, and family size. Results showed that 100% of mothers of sleep-disordered children were classified as insecure with respect to attachment, as assessed by the Adult Attachment Interview, compared with 57% of control group mothers (p less than 0.002). There were no group differences on measures of maternal defensiveness, self-esteem, marital satisfaction, and social support. These results suggest that maternal current perspectives on their relationship history, rather than general psychosocial adjustment, are crucial contributors to the onset and perpetuation of sleep disorders in early childhood.

Child, Preschool↗
PubMed1986

Comparison of contrast x-ray biplane cineangiography and technetium-99m radionuclide scans for measurement of ventricular volumes in human autopsy hearts.

The area-length method is widely used in the determination of left ventricular volume. Although previous studies have reported that this technique overestimates true volume (TV), it is unknown whether this overestimation is the same at different volumes. In the present study, with the use of 10 postmortem human hearts, left ventricular volumes were determined by contrast x-ray biplane cine ventriculography (LVA), biplane radionuclide (LVR), and absolute-counts (LVC) technetium scans, and the results were correlated with TV. LVA correlated well with TV (r = 0.98). LVR correlated well with TV (r = 0.97), and LVR also correlated well with LVA (r = 0.96). Both area-length techniques (LVA and LVR) resulted in overestimation of TV with an upward shift of the regression line of 30.4ml +/- 3.8 (SEM) for LVA and 28.5 +/- 4.4 for LVR. The percentage of overestimation error was significantly greater at smaller left ventricular volumes (error = 33% at TV = 30ml and 10% at TV = 100ml, p less than 0.001). LVC correlated well with TV (r = 0.99), TVA, and LVR but underestimated TV. Thus left ventricular volumes can be reliably obtained from LVR and LVA by means of the area-length method and from LVC. When the area-length method is utilized, the percentage of error in the determination of left ventricular volume is proportional to 1/TV.

Angiocardiography↗
PubMed1985

Comparison of three semiautomatic methods for determination of left ventricular ejection fraction from gated cardiac blood pool images.

A number of computer programs exist for the determination of ejection fraction from gated blood pool images. Three commercially available algorithms were compared on the same radionuclide data from 50 catheterized patients. The methods used were: (1) simple thresholding, (2) second derivative edge determination, and (3) a combination of these two. There was good correlation with catheterization ejection fraction for all three methods using smoothed data [r = 0.781, 0.77, 0.84 respectively (P less than 0.01)]. However, interobserver variance was significantly decreased (P less than 0.01) by use of the second derivative method when compared with the other two methods and catheterization. Thus, if accuracy and low interobserver variance are required, then a combination of a second derivative and thresholding method is preferable.

Cardiac Catheterization↗
PubMed1985

The effect of adding mannitol or albumin to a crystalloid cardioplegic solution: a prospective, randomized clinical study.

To determine if the myocardial protection afforded by a cold crystalloid potassium cardioplegic solution could be improved by the addition of either mannitol or albumin, a prospective clinical study was undertaken in which 58 patients undergoing elective aortocoronary bypass were randomized to one of three groups. Each group featured a different cardioplegic solution. The solutions were a standard potassium crystalloid solution, a solution containing mannitol sufficient to raise the osmolality by 20 to 30 mOsm, and a solution containing 5% albumin. Preoperative, intraoperative, and postoperative evaluation included serial measurements of ejection fraction, myocardial-specific isoenzyme, and hemodynamic indexes of performance. Electrocardiographic evaluation for perioperative myocardial infarction and the need for postoperative inotropic and mechanical support were also included. No differences were found among the groups. Therefore, although the use of mannitol or albumin has been shown to be beneficial in an experimental setting, superiority of either additive could not be demonstrated clinically.

Albumins↗
PubMed1984

Exogenous Aspergillus endophthalmitis.

A 49-year-old man developed Aspergillus endophthalmitis after a perforating corneal injury. The infection was successfully treated with antifungal therapy and surgery.

Amphotericin B↗
PubMed1983

[Contribution of direct immunofluorescence diagnosis to the epidemiology of acute viral respiratory infections in young children].

Rapid diagnosis by immunofluorescence (IF) has enabled us to study the epidemiology of acute viral respiratory diseases in infants admitted to the CHRU at Caen between January 1980 and December 1982. 809 nasal aspiration samples were examined. Respiratory Syncytial Virus (RSV) was recovered in 36% of cases. These were observed during the four winter outbreaks which occurred during the study period and were extensive in 1980-1981 and 1982-1983. A virus was demonstrated in 13.5% of the 515 RSV negative specimens: 25 Rhinovirus, 21 Myxovirus parainfluenzae 3, 19 Adenovirus, 3 Myxovirus influenzae A, 2 Myxovirus influenzae B. RSV is the predominant pathogen as it is the most frequent and is responsible for more severe forms. However, epidemics vary from year to year and from one town to another. Rhinovirus, Myxovirus parainfluenzae 3 and Adenovirus infections are less frequent. Rhinovirus infections occur throughout the year and are certainly underestimated as isolation of the virus is difficult. Most Myxovirus parainfluenzae 3 cases occur in winter, and IF largely facilitates their diagnosis. Adenovirus infections are endemic and serotype 7 is frequent.

Acute Disease↗
PubMed1979

[Surgical correction of corneal astigmatism after corneal graft].

We performed Troutman's technique of corneal wedge resection in 6 patients who had substantial astigmatism after penetrating corneal grafts. The astigmatism was reduced by 5 to over 15 dioptres, and was stable for up to 36 months. The visual acuity was considerably improved in 5 of the 6 cases. However we could not neither predict the amount of correction nor the axis of the residual astigmatism with this technique. We stress the importance of using a keratometer when performing a penetrating corneal graft.

Adult↗
PubMed1977

Introduction of bacteriophage Mu into Pseudomonas solanacearum and Rhizobium meliloti using the R factor RP4.

Phage Mu-1 and a thermoinducible derivative, Mu-1 cts 62 were inserted into the broad host range R factor RP4. These hybrid plasmids were transferred by conjugation to a phytopathogenic bacterium Pseudomonas solanacearum GMI 1000 and a legume-root nodule bacterium Rhizobium meliloti 2011. The Mu genome is transcribed and tranlated in these new hosts: P. solanacearum (RP4:Mu cts) cultures have a spontaneous production of about 5 X 10(5) plaque-forming units ml-1 which is similar to the frequency of spontaneous Mu production in E. coli; the Mu production of R. meliloti is lower (about 10(2) plaque-forming units ml-1).

Anti-Bacterial Agents↗