Biomedical subjects

C Place

Publications and source records attributed to C Place.

12 recordsLinked to original sources

PubMed2005

The Modified-Modified Schober Test for range of motion assessment of lumbar flexion in patients with low back pain: a study of criterion validity, intra- and inter-rater reliability and minimum metrically detectable change.

PURPOSE: The objective was to estimate the psychometric properties of the Modified-Modified Schober Test (MMST). DESIGN: This study compared range of motion measurements of lumbar flexion in low back pain (LBP) patients using the MMST with measurements calculated on X-rays as the gold standard, and compared the measurements taken by two independent examiners. METHOD: This study was conducted at the main hospital in the Outaouais area, Quebéc, Canada. Thirty-one subjects with LBP from private and public clinics participated in the study. After a warm-up session, measurements with the MMST were taken in neutral position and an X-ray technician took an exposure in the same position. RESULTS: Pearson's correlation test (r) between measurements made with the MMST and the gold standard, intra-class correlation coefficient (ICC), minimum metrically detectable change (MMDC) and confidence interval (CI) were used to analyze the data. The MMST demonstrated moderate validity (r=0.67; 95%CI 0.44-0.84), excellent reliability (intra: ICC=0.95; 95%CI 0.89-0.97; inter: ICC=0.91; 95%CI 0.83-0.96) and a MMDC of 1 cm. CONCLUSIONS: In our sample of LBP patients, the MMST showed moderate validity but excellent reliability and MMDC.

Adult↗

PubMed2004

Base-sequence-dependent sliding of proteins on DNA.

The possibility that the sliding motion of proteins on DNA is influenced by the base sequence through a base pair reading interaction, is considered. Referring to the case of the T7 RNA-polymerase, we show that the protein should follow a noise-influenced sequence-dependent motion which deviate from the standard random walk usually assumed. The general validity and the implications of the results are discussed.

Base Pairing↗

PubMed2003

Transverse fluctuation analysis of single extended DNA molecules.

We observed fluctuations of elongated DNA molecules by fluorescence microscopy. The molecules are fixed at both ends and undulate. Mode analysis of the thermally excited undulations of the labeled DNA molecules gives access to the spectral density of the amplitude fluctuations. From these measurements we estimate the tension acting on the DNA molecules. We found the forces to be within the entropic elasticity range of a typical DNA molecule (measured on the single-molecule level).

Computer Simulation↗

PubMed2002

Observation by fluorescence microscopy of transcription on single combed DNA.

Molecular combing is a powerful procedure for aligning a large array of DNA molecules onto a surface. This technique usually leads to an overstretching of about 150% of the molecules' contour length. By changing the magnitude of capillary forces during the combing process, we were able to reduce the relative extension of the DNA molecules. Thus we achieved combing of T7 DNA with an extension close to its molecule contour length. We checked the ability of combed DNA to interact with DNA binding proteins. Using the T7 bacteriophage transcription system, we investigated the transcription activity of RNA polymerase on combed DNA by direct visualization of newly synthesized fluorescent RNAs. Our experiments show that no transcription activity occurs on overstretched DNA molecules, whereas we observe a transcription activity for nonoverstretched molecules. This activity is observed both in multiple initiation experiments and for one immobilized T7 RNA polymerase per promoter. These results open possibilities for the study of single enzyme actions on combed DNA by optical methods.

Bacteriophage T7↗

PubMed1999

Studies of contacts between T7 RNA polymerase and its promoter reveal features in common with multisubunit RNA polymerases.

We have used UV-laser mediated cross-linking, DNase I footprinting and KMnO4 reactivity to probe the interaction between T7 RNA polymerase (RNAP) and a consensus promoter during the early stages of transcription. In a binary complex formed in the absence of substrate on a supercoiled plasmid, direct contacts were observed on the template (T) strand at positions -17, -5, and +3 and on the nontemplate (NT) strand at position -8. These contacts lie within the DNase I cleavage footprint from positions -21 to +11 on the T strand and from positions -17 to +16 on the NT strand and straddle sites of enhanced reactivity of thymines to KMnO4 at position -3 on the T strand and position -2 on the NT strand. Use of supercoiled plasmid templates has allowed the mapping of contacts in the initiation region of the promoter in the binary complex for the first time. Upon addition of GTP, T7 RNAP enters a reiterative mode of synthesis, producing a ladder of poly(G) products. Under these conditions the downstream contact on the T strand switched from position +3 to +4 and +5 while the contact at position -17 was maintained. Under conditions in which the synthesis of transcription products is limited to 6-7 nucleotides, only the contact at position -17 on the T strand was preserved. A comparison of these results with the interaction of Escherichia coli RNA polymerase at the lac promoter reveals strong similarities in the manner in which these polymerases recognize their promoters.

Bacteriophage T7↗

PubMed1996

A gene responsible for a sensorineural nonsyndromic recessive deafness maps to chromosome 2p22-23.

The recessive mode of transmission accounts for approximately 75% of inherited non syndromic deafness cases. We have previously designed the conditions for linkage studies of this highly heterogeneous disorder [Guilford et al. (1994) Nature Genet. 6, 24-28]. Here, using a similar approach, we have studied the segregation of a gene responsible for congenital, profound and fully penetrant sensorineural deafness in a consanguineous family living in an isolated region of Lebanon. A maximum lod score of 8.03 (theta = 0.00) was detected with a new polymorphic marker, AFMa052yb5 (D2S2144). Observed recombinants and homozygosity mapping define a maximum interval of 2 cM for this gene, DFNB6, which lies between AFMb346ye5 (a new polymorphic marker) (D2S2303) and AFM254vc9 (D2S174) on chromosome 2p22-23.

Base Sequence↗

PubMed1996

Mapping of DFNB12, a gene for a non-syndromal autosomal recessive deafness, to chromosome 10q21-22.

We report here, the localization of a new recessive non-syndromal deafness gene (DFNB12) to 10q21-22 by linkage analysis, of a Sunni family. Affected individuals suffer from congenital profound sensorineural hearing loss. A maximum LOD score of 6.40 (theta = 0.00) was obtained with locus D10S535. Analysis of patients carrying recombinations mapped the gene distal to D10S529 and proximal to D10S532, delineating an interval between 11 and 15 cM. Three deaf mouse mutants Jackson circler (jc), Waltzer (v) and Ames waltzer (av) have been localized to the homologous murine region on chromosome 10. Each of these mouse mutants is a candidate mouse model for the DFNB12-associated hearing impairment.

Adolescent↗

PubMed1993

The impact of HIV-1 infection on phenotypic and functional parameters of cellular immunity in chimpanzees.

As a means of assessing the immunological impact of HIV infection in the chimpanzee, as well as the participation of the cellular components in the control of HIV infection in these animals, various aspects of cellular immunity were investigated in chronically HIV-infected chimpanzees. Eight HIV-1-infected chimpanzees were included in this study; two of them were infected for more than 5 years and six for nearly 3 years at the time of study. All of the chimpanzees received either 40 or 100 TCID50 of HTLV-IIIB. Circulating peripheral blood lymphocytes were studied by flow cytofluorimetric analysis in order to reveal possible alterations in the CD4:CD8 ratio, as well as in specific CD4+ and CD8+ cell subpopulations. Chronically infected chimpanzees did not present significant alterations in the percentage of CD4+ or CD8+ lymphocyte subsets. Interestingly, the CD8+/CD57+ cell subset was not detectable. The expression of markers for activation on circulating lymphocytes, usually higher in the HIV-infected patients, was not altered in infected animals. The functional aspects of specific anti-HIV-1 non-MHC and MHC-restricted cellular cytotoxic reactivities were also investigated. The results were compared with the findings in normal uninfected chimpanzees and in HIV-infected humans. Only one chimpanzee (881) developed a detectable, specific non-MHC-restricted anti-HIV-1- reactivity. Compared to that seen in humans, the ontogeny of this activity is delayed. Among the other infected chimpanzees, no specific anti-HIV cellular reactivities were detectable in the peripheral blood. In chimpanzees, HIV-1 infection evidently does not elicit the same strong cellular reactivity as that detected in infected patients. The absence of chronic cellular activation, despite continued viral replication, may highlight a key determinant in HIV-1-induced pathogenesis that is likewise absent in infected chimpanzees.

Animals↗

PubMed1989

Alternate approaches to pelvic abscess drainage after cystectomy.

Pelvic abscesses and fluid collections are relatively common complications of major pelvic surgery. When a radical cystectomy has been performed, the ultrasonic acoustic window to normal anatomic landmarks is lost and bowel loops prolapse into the anatomic pelvis. This makes standard suprapubic ultrasonography (US) either difficult or nondiagnostic and often obscures significant pathology. The current use of high-frequency endocavitary US transducers permits an alternate view of the remaining pelvic structures. Coronal transgluteal scans also permit a limited view of the presacral area. These approaches were used in drainage of pelvic abscesses after cystectomy using the transrectal, transurethral, transperineal, and transabdominal routes under US guidance.

Abscess↗

PubMed1988

Calcification in a recent cerebral infarct--radiologic and pathologic correlation.

This 60 year old male developed a right hemiplegia and aphasia. A C.T. head scan showed a cerebral infarct which appeared hyperdense on a subsequent scan done 18 days after presentation. This was interpreted as indicating a hemorrhagic transformation resulting in discontinuation of anticoagulation therapy. At autopsy, the area of infarction in the left frontoparietal hemisphere appeared intensely green due to breakdown of the blood-brain barrier in the presence of jaundice. A striking finding on microscopy was the presence of calcium salts throughout the area of infarction but most prominent in the grey matter at the periphery of the infarct corresponding to the areas which appeared hyperdense on the CT head scan and stained intensely with bilirubin. There was no evidence of recent hemorrhage. This case illustrates that calcification can occur within weeks after the onset of a recent cerebral infarct and should be considered when interpreting the development of C.T. scan hyperdensity in recent cerebral infarcts.

Brain Diseases↗

PubMed1987

Two unusual causes of dysphagia: a pictorial essay.

Dysphagia was the presenting symptom in two adult patients. One had a mediastinal pancreatic pseudocyst, the other a pulmonary sling. The role of imaging methods in making the diagnoses is illustrated.

Adult↗

PubMed1981

An open, multi-centre evaluation of a 5-day course of pivmecillinam in urinary tract infections in general practice.

One hundred and eleven general practice patients (101 females and 10 males) with acute uncomplicated cystitis received a 5-day course of pivmecillinam at a daily dose of 200 mg 3-times a day. Positive bacteriological cultures were found in 63 (57%) patients before treatment and three-quarters of all patients were totally symptom-free after treatment, with the post-treatment clinical symptom score falling by 94%. In those patients with a positive culture the bacteriological cure rate was 90%. Pivmecillinam was generally well tolerated. Side-effects were reported in 8 (7%) patients and only 1 of these patients had to stop treatment prematurely.

Adolescent↗