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K Sutherland

Publications and source records attributed to K Sutherland.

At least 19 recordsLinked to original sources
PubMed1997

Cloning and sequencing of the mouse Gli2 gene: localization to the Dominant hemimelia critical region.

The GLI family of zinc finger genes has been implicated in both neoplastic and developmental disorders. We have cloned and sequenced the mouse homolog of the zinc finger gene Gli2 and demonstrated significant similarity to the human GLI3 gene. We have also localized Gli2 to mouse chromosome 1, in the vicinity of the morphogenetic mutation Dominant hemimelia (Dh), which is characterized by tibial hemimelia, poly/oligodactyly, and a number of visceral abnormalities, most strikingly absence of the spleen. Using a Gli2-associated microsatellite, we demonstrated no recombination between Dh and Gli2 in a Dh intraspecific backcross. Gli2 is expressed in Dh heterozygotes and homozygotes. However, using a combination of mismatch analysis and direct sequencing, we have failed to identify any mutations in the coding sequence of Gli2 from Dh. We have also demonstrated that it is unlikely that there are any Gli genes in the mouse genome in addition to the previously described Gli, Gli2, and Gli3.

Amino Acid Sequence↗
PubMed1996

A quantitative and qualitative analysis of prion protein immunohistochemical staining in Creutzfeldt-Jakob disease using four anti prion protein antibodies.

Creutzfeldt-Jakob disease (CJD) is the most common spongiform encephalopathy affecting humans. Prion protein (PrP) immunohistochemistry may be useful for studying the localization of prion protein and assessing its role in CJD, the accumulation of a specific protease resistant PrP isoform being apparently pathognomic to the spongiform encephalopathies. However, a number of factors influence the results of immunostaining, making interpretation and comparisons between the staining of different PrP antisera difficult. This study has examined qualitatively and quantitatively the staining produced by four antisera raised to a variety of prion protein homologues in two cases of CJD and two age-matched controls. Quantitative analysis was provided through the use of custom designed image analysis software. Kuru, granular and multicentric plaques, cellular, perivacuolar and white matter PrP deposits were observed in CJD cases with all four antisera. No significant immunostaining was seen in the control tissue. Some antibody specific staining patterns were observed qualitatively; however, quantitative analysis showed statistically significant correlations between all the antisera on the diseased brain tissue. Prion protein immunohistochemistry is thus useful in interpreting patterns of protein distribution in diseased brain but care may be required in interpreting the results of a single antibody.

Aged↗
PubMed1996

Analysis of proprioception in the posterior cruciate ligament-deficient knee.

The purpose of this study was to demonstrate loss of proprioception with posterior cruciate ligament (PCL) deficiency. Eight patients with isolated PCL-deficient knees were examined to determine whether or not the proprioceptive function of the knee joint was affected or impaired by the previous tear of the PCL. The patients were examined for perception of passive movement of the knee joint using a motorized apparatus which extended or flexed the patient's knee at a rate of 0.5 deg/s in a randomized sequence. The patient's normal contralateral knee was used as a control. This study demonstrated a significant difference in proprioception in the patient's PCL-deficient knee. All eight PCL-deficient knees clearly demonstrated slower perception of passive movement when compared with the contralateral normal knee. Injuries to the PCL resulting in impaired proprioception may play a role in knee instability, further damage and ultimately the degenerative changes frequently seen in the long-term follow-up of PCL-deficient knees.

Adult↗
PubMed1996

Prion protein genotype and pathological phenotype studies in sporadic Creutzfeldt-Jakob disease.

A comparative semi-automated morphometric study was performed on the distribution of prion protein, spongiform change and astrocytosis in the brains of nine cases of sporadic Creutzfeldt-Jakob disease of differing genotype at the methionine-valine polymorphism at codon 129 of the prion protein gene. Custom-designed image analysis software was used to produce objective figures for each of the different pathological features throughout 13 different areas of the brain used for analysis. A significant positive correlation was observed between prion protein deposition and astrocytosis in all cases and no significant correlation was observed between spongiform change and prion protein deposition. Different patterns of pathology were found to relate to codon 129 genotype; valine homozygosity favoured the targeting of pathology to deep grey matter structures, while methionine homozygosity favoured cortical targeting of pathology. These results provide evidence that prion protein deposition is closely associated with an astrocytic reaction and suggest that codon 129 genotype may influence the pathological phenotype.

Aged↗
PubMed1996

Quantitative videobronchoscopy: a new technique to assess airway caliber.

Quantitative assessment of airway caliber is generally confined to indirect physiologic methods or to radiographic techniques. Fiberoptic bronchoscopy provides a direct view of airways, permitting quantification of airway caliber by image analysis. We investigated the characteristics of a bronchoscopic imaging system, determined its limitations in quantification and the corrections necessary for accurate assessment of image dimension, validated the methodology with airway models, and applied the technique to airways in vivo. The system comprised a bronchoscope, videocamera, videocassette recorder (VCR), computer with a frame grabber, and image-analysis program. Image quantification was affected by two sources of distortion: (1) Distance distortion: a loss of image resolution with increasing distance between the object and bronchoscope, requiring determination of the operational distance range. (2) Radial distortion: a progressive reduction in image size from the center to the periphery of the bronchoscopic field of view (FOV), requiring correction of airway dimension according to airway size and location in FOV. Validation of the methodology with different sized airway models indicated an underestimation of measured diameters, which normalized with distortion correction. We provide an example of quantitative videobronchoscopy with measurements of in vivo airway narrowing due to vagal stimulation in the anesthetized dog. Measurements of airway narrowing made with videobronchoscopy were also compared with those made with high-resolution computer-assisted tomography (HRCT) which suggested that the two technologies provide unique but complementary perspectives on airway dimensions. We conclude that videobronchoscopy and image analysis provide a novel and accurate method for the quantification of airway caliber.

Animals↗
PubMed1996

Objective quantification of prion protein in spinal cords of cases of Creutzfeldt-Jakob disease.

A recent investigation into prion protein (PrP) deposition in cases of Creutzfeldt-Jakob disease (CJD) has suggested that the spinal cord is affected in some cases of this disease. In an attempt to measure this phenomenon we have used quantitative image analysis techniques to assess the amount of PrP deposited in the spinal cords of three different cases of CJD. By using an automatic method of image intensity threshold setting we have measured the tissue area occupied by PrP in a non-subjective manner. The ranking of these different cases has confirmed that suggested by visual inspection. This analysis shows a substantial variation in the quantity of PrP positivity observed when a panel of different PrP antibodies was compared, confirming early findings. The distribution of PrP across the spinal cord has also been mapped using the image analysis system.

Antibody Specificity↗
PubMed1995

High-resolution genotyping of Campylobacter coli identifies clones of epidemiologic and evolutionary significance.

Campylobacter coli strains from clinical and other sources were examined in terms of O (heat-stabile; HS) serotype and by several molecular typing techniques. Restriction fragment length polymorphism (RFLP) around the three 16S rRNA genes revealed 10 variants, none found in Campylobacter jejuni. RFLP analysis of a polymerase chain reaction amplicon generated from the flagellin gene (flaA) yielded 11 polymorphism groups, some of them linked to HS serotypes. Enlarged flaA genes, contributing three further polymorphisms, were detected in strains isolated from fresh water. Restriction of the genome with SmaI and pulsed-field gel electrophoresis was the most discriminatory typing method, detecting 33 macrorestriction profiles that subtyped within HS serotypes. The coincidence of HS serotype and the three genotypic markers identified clonal lines of evolutionary and epidemiologic significance.

Animals↗
PubMed1995

Molecular subtyping scheme for serotypes HS1 and HS4 of Campylobacter jejuni.

We describe a molecular subtyping scheme for two principal O (heat-stable [HS]) serotypes of Campylobacter jejuni, HS1 and the HS4 complex. A 16S rRNA gene-specific probe confirmed that almost all the C. jejuni strains had three copies of this gene, and strains could be assigned with complete typeability to 1 of 16 combined (Pst1 and HaeIII) 16S ribotypes. Macrorestriction profiles (mrps) consisting of up to 10 SmaI fragments from approximately 40 to approximately 480 kbp were resolved by pulsed-field gel electrophoresis (PFGE). There were 11 mrps among the HS1 strains and 9 mrps among HS4 strains which corresponded to valid types--they occurred in multiple isolates, hosts, places, and times. There were 14 additional single-strain mrp fingerprints in HS1 and 20 in HS4. PFGE exhibited complete typeability when formaldehyde fixation of cells was employed, and PFGE was generally more differential than ribotyping. The data presented elucidate a high-resolution genotypic subtyping scheme for these common subspecific phenotypes of C. jejuni, which is both coherent and efficient for epidemiological purposes.

Animals↗
PubMed1994

Flagellin gene polymorphism analysis of Campylobacter jejuni infecting man and other hosts and comparison with biotyping and somatic antigen serotyping.

Flagellin gene sequence polymorphisms were used to discriminate amongst 77 strains of Campylobacter jejuni from sporadic and outbreak-associated human enteric infections, and from chickens, sheep and calves. The results were assessed in relation to Lior biotyping and serotyping (Penner somatic antigens). Eight DNA PCR-RFLP patterns (genotypes) were identified by analysis of HinfI fragment length polymorphisms in flagellin gene (flaA) polymerase chain reaction (PCR) products. One genotype (F-1) was a feature of 55% of strains. Strains within the genotypes were heterogeneous with respect to somatic antigens with 12 serogroups represented amongst the C. jejuni isolates of flaA type F-1. Serogroups Pen 1, 2 and 23 were the commonest (45%) amongst the 20 different serogroups represented. Several unique clusters of isolates with diverse biotypes were defined, and one cluster (F-7/Pen 23) contained epidemiologically implicated outbreak strains as well as sheep and calf isolates. We conclude that HinfI flaA typing is reproducible and offers high typability, and its combination with serogrouping provides a novel approach to characterizing isolates of C. jejuni with improved discrimination.

Animals↗
PubMed1994

Joy in the job.

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Christianity↗
PubMed1994

Inhibition of DNAse activity in PFGE analysis of DNA from Campylobacter jejuni.

DNAse-positive strains of Campylobacter jejuni degrade their chromosomal DNA during standard preparative procedures before pulsed-field gel electrophoresis (PFGE). A simple method for inactivation of this DNAse activity is described. Formaldehyde fixation of the bacterial cells resulted in the preservation of the DNA in a state suitable for restriction digestion and subsequent electrophoretic analysis.

Campylobacter jejuni↗
PubMed1994

Hepatitis B virus surface antigen binds to apolipoprotein H.

We have previously demonstrated that a plasma membrane-enriched fraction isolated from human liver is capable of binding recombinant hepatitis B surface antigen (rHBsAg) (P. Pontisso, M. A. Petit, M. Bankowski, and M. E. Peeples, J. Virol. 63:1981-1988, 1989). In this study we have separated the plasma membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used a ligand-blotting technique to identify a 46-kDa rHBsAg-binding protein. This protein could be removed from the membranes with a weakly acidic buffer, implying that it is peripherally bound. Examination of human serum revealed that the 46-kDa binding protein is a serum protein. Isolation of plasma lipoproteins revealed that the binding protein is in part associated with chylomicrons and high-density lipoproteins, both of which are targeted to the hepatocyte during the normal course of lipid metabolism. The binding protein was identified as apolipoprotein H (apo H), also known as beta 2-glycoprotein I, on the basis of copurification of the rHBsAg-binding activity with the apo H protein and the ability of cDNA-expressed apo H to bind rHBsAg. Serum-derived HBsAg also binds to apo H, indicating that binding is not unique to rHBsAg. Binding is saturable, requires only the small S protein of rHBsAg, and is inhibited by excess rHBsAg, antibodies to HBsAg, and antibodies to apo H. The binding activity of apo H is destroyed upon reduction, indicating that 1 or more of its 22 disulfide bonds are required for interaction with rHBsAg. The possibility that an interaction between hepatitis B virus particles and lipoprotein particles may facilitate entry of the virus into hepatocytes is discussed.

Apolipoproteins↗
PubMed1994

Automatic quantification of amyloid plaque formation in human spongiform encephalopathy.

This study compared a panel of three different prion protein antibodies with conventional plaque staining methods--Congo Red, Periodic acid Schiff and sulphated Alcian blue--to investigate amyloid plaque formation in cases of human spongiform encephalopathy (HSE). Tissue samples were taken from the cerebellum in nine sporadic cases of Creutzfeldt-Jakob Disease, with plaque formation noted on routine histology, and one case of Gerstmann-Straussler Scheinker syndrome. Using image analysis techniques, a semi-automatic system of plaque quantification was devised to measure the relative performance of these different staining methods. A total figure of percentage tissue area stained positively was returned by the system in each case analysed. A significant statistical correlation was observed among all three antibodies (r > 0.9, P < 0.01, in all comparisons) and a significant improvement was observed when the average antibody staining figures were compared to those of the Alcian blue technique (P < 0.05). The distribution of plaques across the cerebellar layers observed here appears to confirm earlier research findings. A strong correlation was found between staining in the two cerebellar hemispheres (r = 0.97, P < 0.01). This novel image analysis system has considerable potential for objective assessment of the pathology of HSE.

Aged↗
PubMed1994

Novel application of image analysis to the detection of spongiform change.

Spongiform change is the characteristic neuropathologic abnormality within the brain in Creutzfeldt-Jakob disease, the most common human spongiform encephalopathy, but traditional methods of evaluating this abnormality are subjective and laborious. In order to overcome these difficulties, a quantitative method of assessment of spongiform change was devised and implemented using image analysis techniques. Successful validation of this system was performed by subjective and objective comparison with a neuropathologist's assessment. In a test-set of 50 microscopic images a strong positive rank correlation (Rs = 0.91) was established between the image analyzer and the neuropathologist. This system should facilitate large-scale analysis of different patterns of spongiform change in cases of human spongiform encephalopathy.

Brain↗
PubMed1993

Degradation of biomaterials by phagocyte-derived oxidants.

Polymers used in implantable devices, although relatively unreactive, may degrade in vivo through unknown mechanisms. For example, polyetherurethane elastomers used as cardiac pacemaker lead insulation have developed surface defects after implantation. This phenomenon, termed "environmental stress cracking," requires intimate contact between polymer and host phagocytic cells, suggesting that phagocyte-generated oxidants might be involved. Indeed, brief exposure of polyetherurethane to activated human neutrophils, hypochlorous acid, or peroxynitrite produces modifications of the polymer similar to those found in vivo. Damage to the polymer appears to arise predominantly from oxidation of the urethane-aliphatic ester and aliphatic ether groups. There are substantial increases in the solid phase surface oxygen content of samples treated with hypochlorous acid, peroxynitrite or activated human neutrophils, resembling those observed in explanted polyetherurethane. Furthermore, both explanted and hypochlorous acid-treated polyetherurethane show marked reductions in polymer molecular weight. Interestingly, hypochlorous acid and peroxynitrite appear to attack polyetherurethane at different sites. Hypochlorous acid or activated neutrophils cause decreases in the urethane-aliphatic ester stretch peak relative to the aliphatic ether stretch peak (as determined by infrared spectroscopy) whereas peroxynitrite causes selective loss of the aliphatic ether. In vivo degradation may involve both hypohalous and nitric oxide-based oxidants because, after long-term implantation, both stretch peaks are diminished. These results suggest that in vivo destruction of implanted polyetherurethane involves attack by phagocyte-derived oxidants.

Animals↗