Biomedical subjects

C Leboeuf

Publications and source records attributed to C Leboeuf.

18 recordsLinked to original sources

PubMed2005

[Ultrasound biomicroscopy of posterior chamber phakic intraocular lenses: a comparative study between ICL and PRL models].

PURPOSE: To evaluate the anatomic relationships of the implantable contact lens (ICL) and the phakic refractive lens (PRL) posterior chamber phakic intraocular lenses (PCP IOL) using ultrasound biomicroscopy (UBM). MATERIAL AND METHODS: Seventeen phakic myopic eyes corrected with ICL, and 14 phakic myopic eyes that had had PRL implantation, were examined retrospectively using UBM. The main parameters measured and compared were anterior chamber depth, central and peripheral distance between PCP IOL and the crystalline lens, and exact lens haptic position. RESULTS: The mean distance between the PCP IOL and the central endothelium was 2398+/-203 microm and 2640+/-230 microm in the ICL and PRL groups, respectively. The central vault between the implant and the crystalline lens was greater in eyes with ICL (ICL, 402+/-194 microm; PRL, 256+/-187 microm, p<0.05). However, the incidence of lens contact on the peripheral level was higher in the ICL group (41%) than in the PRL group (29%), and the difference between the two implants in the peripheral crystalline lens-PCP IOL distance was significant (p<0.05). Both IOL haptics appeared to be correctly positioned in the sulcus in 13 (76%) eyes of the ICL group, and on the zonule in eight eyes (57%) of the PRL group. CONCLUSIONS: PCP IOL implantation is a safe procedure for the correction of high myopia with regard to refractive results. UBM provides a unique tool to noninvasively evaluate the relations of these implants within the posterior chamber, and helps to analyze the mechanisms of crystalline lens and iris complications.

Adult↗

PubMed2005

[Optical biometry of eyes corrected by phakic intraocular lenses].

PURPOSE: The aim of this study was to determine whether eye length measurements obtained with the IOL Master (Zeiss Humphrey) before and after phakic IOL implantation would show any changes. METHODS: In a prospective study, we used the IOL Master to measure optical biometry in 25 myopic eyes of 15 patients before and after phakic IOL implantation (PRL, ICL, Artisan). The differences between both axial length measurements were calculated and compared using a nonparametric Wilcoxon test. RESULTS: The difference between the preoperative and postoperative measurements ranged from -0.16 mm to 0.06 mm and averaged -0.016 mm, which was not statistically significant (p=0.20). Both measurements correlated in a highly positive manner (r=0.999; p<0.0001). The reproducibility of the preoperative and postoperative axial length measurements was very high (coefficient of variation=0.09% and 0.07%, respectively). The precision was 26 microm for preoperative measurements and 19 microm for postoperative measurements. CONCLUSION: Our results showed that postoperative measurements of axial length are highly comparable to preoperative measurements and that optical biometry can achieve highly precise and reliable axial length measurements in eyes with phakic IOLs. This application becomes clinically relevant in evaluating eyes with phakic IOLs that might require cataract surgery. Hence, accurate axial length measurements in eyes with phakic IOLs will be extremely important when cataract occurs in these eyes and when the preoperative measurements are no longer available.

Adult↗

PubMed2003

Histochemical and immunohistochemical protocols for routine biopsies embedded in Lowicryl resin.

Tissue processing and analysis require good preservation of both the shape and content of cells. Lowicryl resin is one of the few embedding media that allow good preservation of both tissue architecture and cellular contents. Therefore, different histochemical and immunohistochemical reactions can be applied to semithin sister sections from one biopsy. Further examination of a zone of interest can be carried out under the electron microscope. The hydrophilic property of Lowicryl resins makes possible different histochemical reactions; however, the technique used for paraffin sections must be adapted for each reaction. Antigenic preservation of cells by low temperature embedding allows immunolabeling on either semithin sections or in the zone of interest on ultrathin sections. We have shown the application and adaptation of different histochemical and immunohistochemical reactions on semithin and ultrathin sections from hepatic biopsies that were large, but thin. The variety of techniques that can be used on sister Lowicryl sections of a single biopsy makes this medium useful for extensive pathological studies of precious needle biopsies.

Acrylic Resins↗

PubMed2001

The stress proteome of Enterococcus faecalis.

Enterococcus faecalis is a resident bacterium of the intestinal tract of humans and animals. This bacterium can be responsible for serious diseases and is one of the largest causes of hospital-based infections. This hardy organism resists many kinds of stresses and is used as a major indicator of the hygienic quality of food, milk, and drinking water. On the other side, enterococci seem to have beneficial role in the development of cheese aroma and are added in certain starter cultures. Since ten years, our laboratory has used the two-dimensional electrophoresis (2-DE) technique to study the response of E. faecalis to physical or chemical stresses as well as to glucose and total starvation. Twenty-seven protein spots on 2-D gels have been identified by N-terminal sequencing or Western blotting which make up the first proteome database of this species. The proteins were classified in four different groups according to their function and their regulation. The first group comprises well-characterized proteins with known protective functions towards stresses. The second group contains enzymes of catabolic pathways. Their implication in stress resistance seems not obvious. A third group are proteins induced in glucose-starved cells belonging to the CcpA regulon. Induction of these enzymes under starvation may serve to increase the scavenging capacity of the cells for nutrients or may be important to mobilize endogenous energetic reserves. Lastly, nine N-terminal amino acid sequences or open reading frames (ORF) showed no homologies with sequences in databases. A comprehensive description of stress proteins of E. faecalis and analysis of their patterns of expression under different environmental conditions would greatly increase our understanding of the molecular mechanisms underlying the extraordinary capacity of this bacterium to survive under hostile conditions.

Acids↗

PubMed2000

Cloning, sequencing and characterization of the ccpA gene from Enterococcus faecalis.

Enzymes involved in the metabolism of complex carbon and energy sources are unnecessary under conditions of abundant, readily metabolisable nutrients such as glucose or fructose. The repression of these enzymes by glucose has been termed carbon catabolite repression. Mechanisms involved in the carbon catabolite repression in gram-positive bacteria are known to differ from those of gram-negative bacteria such as Escherichia coli. It appears to be mediated by transcriptional repression, requiring trans-acting CcpA, a member of the LacI-GalR family of bacterial regulatory proteins and a cis-acting consensus sequence, designated cre. Here, we report the cloning and characterisation of the chromosomal ccpA gene from Enterococcus faecalis JH2-2. This gene is predicted to encode a 333 amino acids protein with nearly 75% identity to CcpA of Lactobacillus casei.

Amino Acid Sequence↗

PubMed2000

Characterization of the ccpA gene of Enterococcus faecalis: identification of starvation-inducible proteins regulated by ccpA.

Inactivation of ccpA in Enterococcus faecalis leads to reduction of the growth rate, derepression of the galKETR operon in the presence of a mixture of glucose and galactose, and reduction of transcription of ldh in the presence of glucose. Moreover, the E. faecalis ccpA gene fully complements a Bacillus subtilis ccpA mutant, arguing for similar functions of these two homologous proteins. Protein comparison on two-dimensional gels from the wild-type cells and the ccpA mutant cells revealed a pleiotropic effect of the mutation on gene expression. The HPr protein of the carbohydrate-phosphotransferase system was identified by microsequencing, and a modification of its phosphorylation state was observed between the wild-type and the mutant strains. Moreover, at least 16 polypeptides are overexpressed in the mutant, and 6 are repressed. Interestingly, 13 of the 16 polypeptides whose synthesis is enhanced in the mutant were also identified as glucose starvation proteins. The N-terminal amino acid sequences of four of them match sequences deduced from genes coding for L-serine dehydratase, dihydroxyacetone kinase (two genes), and a protein of unknown function from Deinococcus radiodurans.

Bacillus subtilis↗

PubMed1998

Ribosome release factor RF4 and termination factor RF3 are involved in dissociation of peptidyl-tRNA from the ribosome.

Peptidyl-tRNA dissociation from ribosomes is an energetically costly but apparently inevitable process that accompanies normal protein synthesis. The drop-off products of these events are hydrolysed by peptidyl-tRNA hydrolase. Mutant selections have been made to identify genes involved in the drop-off of peptidyl-tRNA, using a thermosensitive peptidyl-tRNA hydrolase mutant in Escherichia coli. Transposon insertions upstream of the frr gene, which encodes RF4 (ribosome release or recycling factor), restored growth to this mutant. The insertions impaired expression of the frr gene. Mutations inactivating prfC, encoding RF3 (release factor 3), displayed a similar phenotype. Conversely, production of RF4 from a plasmid increased the thermosensitivity of the peptidyl-tRNA hydrolase mutant. In vitro measurements of peptidyl-tRNA release from ribosomes paused at stop signals or sense codons confirmed that RF3 and RF4 were able to stimulate peptidyl-tRNA release from ribosomes, and showed that this action of RF4 required the presence of translocation factor EF2, known to be needed for the function of RF4 in ribosome recycling. When present together, the three factors were able to stimulate release up to 12-fold. It is suggested that RF4 may displace peptidyl-tRNA from the ribosome in a manner related to its proposed function in removing deacylated tRNA during ribosome recycling.

Bacterial Proteins↗

PubMed1991

Low back pain.

Low back pain (LBP) affects a large proportion of the population and is an increasingly costly problem in the western world. This review highlights some of the recent theories relating to LBP and the conflicting evidence which has been brought to light. Theories relating to the causes of LBP have included single and multiple factors such as abnormal physical findings, mechanical, psychosocial and economic factors. The two lowest lumbar segments are most often afflicted in LBP sufferers, but the diagnosis of LBP is otherwise uncertain in most cases due to insufficient knowledge relating to the validity of clinical tests, inconsistent terminology and unclear symptomatic patterns. Despite a lack of understanding of the exact anatomical cause of LBP, an abundance of therapeutic models exist, most of which are purely empirical, and few methods have been shown to be clinically useful. Similarly, insufficient knowledge of the causes of LBP makes primary, secondary and tertiary prevention difficult.

Back Pain↗

PubMed1991

Chiropractic care of children with nocturnal enuresis: a prospective outcome study.

Functional nocturnal enuresis is a common problem which causes a great deal of stress to the suffering children and their families. Some chiropractors advocate chiropractic care as a mode of therapy for this complaint. One hundred and seventy-one enuretic children, aged 4 to 15, were treated with chiropractic adjustments, and their number of wet nights was monitored by their parents. The median number of wet nights per week was 7.0 at the onset of the study. After 2 wk without any therapy, the number of wet nights had decreased to 5.6 (p = .01) and by the end of the treatment this figure was 4.0 (p less than .0001). Following the course of treatment, 15.5% of subjects wet a maximum of 2 nights per fortnight, or, where data for the last 2 wk of therapy were unavailable, a maximum of 1 night/wk. This result is less favorable than the therapeutic success of other common types of therapy, which have reported "cure" rates well above 50%. The only variable which predicted treatment outcome was the initial estimate of bed-wetting; the more severe the condition at the onset, the less likely was the child to improve by the end of the study. In the absence of a control group there appears to be no validity in the claim that chiropractic is a treatment of choice for functional nocturnal enuresis.

Adolescent↗

PubMed1990

A review of the research papers published by the international College of Applied Kinesiology from 1981 to 1987.

Applied Kinesiology (AK) is a diagnostic and therapeutic approach used by a large number of chiropractors. AK seminars are conducted worldwide; during these seminars mention is frequently made of the presence of supportive research. A review was undertaken of the type and scientific quality of 50 papers which had been published between 1981 and 1987 by the International College of Applied Kinesiology, 20 of which were classified as research papers. These were subjected to further scrutiny relating to criteria considered crucial in research methodology, namely, a clear identification of sample size, inclusion criteria, blind and naive subjects and statistical analysis. Although some papers satisfied several of these criteria, none satisfied all seven of them. As none of the papers included adequate statistical analyses, no valid conclusions could be drawn concerning their report of findings.

Chiropractic↗

PubMed1990

A review of data reports published in the Journal of Manipulative and Physiological Therapeutics from 1986 to 1988.

Forty-six data reports which appeared in the Journal of Manipulative and Physiological Therapeutics from 1986 to 1988 were reviewed according to specific methodological criteria. There appears to be a need for improved study design in contemporary chiropractic research. Experimental and quasi-experimental studies were most commonly deficient in the areas of reliable methods of measurement, the use of blind assessors and blind, or at least naive, study subjects. Common flaws in surveys were: failure to test the survey instrument prior to the study, not stating the response rate, and omitting discussion of the question of confidentiality. The results confirmed findings obtained in a similar study of data reports of an Australian peer-reviewed chiropractic journal. The use of various types of checklists is recommended for authors and reviewers of chiropractic scientific material.

Bibliographies as Topic↗

PubMed1989

Chiropractic chronic low back pain sufferers and self-report assessment methods. Part I. A reliability study of the Visual Analogue Scale, the Pain Drawing and the McGill Pain Questionnaire.

Comprehensive assessment of the problems of low back pain sufferers requires that (in addition to objective measures and clinicians' judgments) an examination of subjective perception of their difficulties should also be made. Subjective measurement has, in the past, presented several problems to researchers. However, in recent years, several new methods of exploring individual reactions to pain and disability have been developed. These assessment measures have, in the main, been carefully explored with severe chronic, acutely ill and surgical patients, but they have not been shown to be appropriate for use with mild chronic low back pain sufferers. This study examines the reliability of several widely used self-report measures. In general, the measures were shown to have acceptable levels of reliability for use with this population, although recommendations for caution in the use of the pain drawing is urged.

Back Pain↗

PubMed1989

Chiropractic chronic low back pain sufferers and self-report assessment methods. Part II. A reliability study of the Middlesex Hospital Questionnaire and the VAS Disability Scales Questionnaire.

The subjective complaints of 41 chronic low back pain sufferers attending a chiropractic clinic were assessed twice prior to therapy with a widely used psychological self-report assessment tool, the Middlesex Hospital Questionnaire (MHQ) and a newly developed VAS Disability Scales Questionnaire (DISQ), both of which investigate various aspects of certain basic positions and activities. Reliability was generally acceptable with these two questionnaires. Subjects participating in the study were commonly found to score within the normal range on the MHQ, indicating that psychological disturbance was not a major feature of their presentation. However, mild mood disturbance was commonly reported, and a more sensitive tool may need to be developed for this type of mildly affected chronic low back pain sufferers. The DISQ generally indicated subjects were mildly to moderately affected by their low back trouble and that sitting and leisure activities were the most pain provoking. Recommendations for further development of the disability scale are made.

Back Pain↗

PubMed1989

Prevalence of spondylolisthesis, transitional anomalies and low intercrestal line in a chiropractic patient population.

Five hundred and thirty radiographs were screened for the presence of certain lumbosacral anomalies. The prevalence of spondylolisthesis was found to be 5.1%, lumbarization 6.0%, sacralization 5.5% and low intercrestal line 56.9%. There was no greater prevalence in patients suffering from low back pain when compared against those who did not. There was a propensity for a low intercrestal line among females. Contrary to previous claims that lumbarization is more common in men, we found a moderate predilection for this finding among women. No difference between the two sexes was found in the prevalence of sacralization, contradicting previous claims that is more common in females, nor was spondylolisthesis found more frequently in men, contrary to our expectations.

Age Factors↗

PubMed1989

A preliminary investigation of the relationship between certain practice characteristics and practice location: chiropractor-population ratio.

Two surveys of 121 preselected Victorian and South Australian chiropractors were conducted during the period of December 1986 to February 1987 in order to investigate whether practice location (metropolitan area and country town) and chiropractor/population ratio (number of chiropractors per 10,000 inhabitants) have any effect on patient numbers, practice procedures and practitioner attitudes. Practitioners' response rates to the first and second questionnaires were 82% and 61%, respectively. Analysis of data revealed that metropolitan chiropractors utilized more adjunctive therapies than their country town colleagues. Most chiropractors felt that the number of chiropractors in their area was sufficient. However, there appeared to be no difference in patient numbers (patient visits and new patients) and ratio of new patients to patient visits as related to practitioner density or practice location. Patient volume appeared to be practitioner-induced; fewer new patients corresponded to a higher number of revisiting patients, and maintenance care corresponded to a higher number of patient visits.

Adult↗

PubMedDate not supplied

The reliability of specific sacro-occipital technique diagnostic tests.

Four interexaminer and one intraexaminer agreement studies were performed on specific diagnostic tests commonly employed within sacro-occipital technique (SOT). Ten of the tests were evaluated in more than one interexaminer study. Of these, only one test (bilateral supine leg raise with cervical compaction) had at least fair reliability more than once. Six of these 10 tests obtained poor agreement in more than one study. One examiner out of two had a number of excellent and fair intraexaminer values, whereas the other examiner generally had poor results. There may have been some treatment effect as a comparison of the combined intraexaminer diagnosis for two observers after no treatment and after treatment showed that the repeatability diminished from Kappa of 0.36 in untreated cases (which were expected to have high agreement of before and after treatment findings) to a Kappa of 0.27 for those subjects having received treatment (which were expected to have low agreement of before and after treatment findings). It appears unlikely that SOT tests can be reproduced to a sufficiently high degree to constitute useful clinical procedures.

Chiropractic↗

PubMedDate not supplied

The sensitivity and specificity of seven lumbo-pelvic orthopedic tests and the arm-fossa test.

Twenty-nine lumbosacral asymptomatic and 39 symptomatic patients who attended a chiropractic clinic were examined by a practitioner who was blinded to their symptoms. Seven lumbosacral orthopedic tests, along with the arm-fossa test were scrutinized for sensitivity, specificity and diagnostic competency values. Only the arm-fossa test and heel-buttock tests had a significantly higher percentage of positive findings in symptomatic than asymptomatic cases. These same tests were the only ones which could be considered to have an acceptable diagnostic value, when both the sensitivity and specificity were taken into consideration by Youden's index. The number of positive tests was unrelated to the presence of lumbosacral symptoms. Orthopedic tests which appeared to strain several adjacent anatomical structures were most commonly positive. No particular combination of tests could predict if the patient was symptomatic or asymptomatic. Only the heel-buttock test had some predictive value. It appears that these tests were of limited value in differentiating between the symptomatic and asymptomatic subjects who attended the study clinic.

Chiropractic↗

PubMedDate not supplied

A survey of recently graduated chiropractors in Australia.

A survey was performed in Australia to study recently graduated chiropractors. Five general themes were investigated: a) personal and professional demographic profile, b) personal and professional attitudes, c) referral patterns, d) diagnostic procedures, and e) therapeutic procedures. Consideration is given to the possible development of the chiropractic profession in Australia.

Attitude of Health Personnel↗