Search PubMed⌕ Search

Biomedical subjects

K Sutherland

Publications and source records attributed to K Sutherland.

At least 19 recordsLinked to original sources
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.

Explore the source record for details and available documents.

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↗
PubMed1992

The ultimate birth center: a collaborative model for innovation.

Lest these descriptions sound too good to be true, Virginia Mason Birth Center is not utopia. It is a real place with real problems and struggles. Implementing and maintaining personalized, high-quality obstetric care to the childbearing woman and her family has not come easily. Innovations continue to be developed in response to patients' and providers' desire for birth services that are flexible, sensitive, and designed around families' preferences and needs. A common philosophy continues to guide a dedicated staff, administration, and provider group within a framework of collaboration, innovation, and quality to enable a wonderful professional practice to evolve.

Birthing Centers↗
PubMed1989

Histopathologic examination of material from angioplasty balloon catheters used in vivo in human coronary arteries.

Reports on vascular pathology post-PTCA in both human and animal coronary vessels have revealed medial and intimal cracks and tears, thrombus formation, platelet accumulation, and loss of endothelial cells. The extent and type of damage can currently be assessed in vivo at the macro level by means of coronary artery angiography. However, this technique cannot define vessel wall characteristics at the cellular level. Our hypothesis is that vessel wall material may adhere to the balloon and thus provide a source for coronary artery cytological investigation in vivo. Ten balloon catheters were evaluated to discern any material which was dislodged from the coronary artery and which remained attached to the balloon catheter or guide wire. Our results indicate that angioplasty catheter balloons frequently have adherent collagen, endothelial cells, organized thrombus, and plaque with obvious cholesterol clefts, that can be retrieved and examined histologically. We conclude that material is often dislodged from the plaque during PTCA. In addition, plaque material removed by the balloon catheter offers an unusual opportunity to analyze the morphologic characteristics of cells from the human coronary artery in vivo.

Adult↗
PubMed1989

Emergency medical care requirements for large public assemblies and a new strategy for managing cardiac arrest in this setting.

During the 1986 World's Exposition held in Vancouver, British Columbia, the types and frequencies of emergency medical problems were assessed. The average number of patients seeking care was 3.93 +/- 0.95 per 1,000 visitors (daily range, 1.94 to 6.8). Patient loads were linearly related to gate attendance, but the correlation was imperfect (P less than .001, r = .63). Only 4.4% of patients evaluated on site by nurses and paramedics were referred for additional testing and treatment: of these patients, 30% had suspected serious musculoskeletal injury, 16% had abdominal pain, and 25% had complaints of chest pain, dizziness, or loss of consciousness. Lay employees (security personnel) were trained to use automatic external defibrillators. There were six cardiac arrests (0.3 per million visitors). Two patients collapsed with ventricular fibrillation, were defibrillated by lay personnel, quickly regained consciousness, and survived. The other arrests were associated with asystole or electromechanical dissociation; no shocks were inappropriately given, and all four died. We conclude that four of every 1,000 persons at this assembly sought emergency medical care, that 95% of the problems seen were minor with few requiring physician skills, and that the automatic external defibrillator was suited for this setting and could be used by lay responders to provide early definitive treatment.

Adolescent↗
PubMed1978

Inhibition of liver prenyltransferase by alkyl phosphonates and phosphonophosphates.

n-Pentyl and n-decyl phosphonate and the corresponding phosphonophosphates were found to inhibit cholesterol synthesis from mevalonate in the 10000 X g supernatants of liver homogenates and the synthesis of farnesyl pyrophosphate from geranyl and isopentenyl pyrophosphate by purified liver prenyltransferase. Kinetic analysis of the inhibition of prenyltransferase showed that the phosphonates and the phosphonophosphates interacted with two forms, or two sites, of the enzyme. The order of increasing potency was C5-phosphonate less than C10-phosphonate less than C5-phosphonophosphate less than C10-phosphonophosphate. The phosphonophosphates were at least ten times stronger inhibitors than the phosphonates.

Animals↗
PubMed1978

N5,10-methylenetetrahydrofolate reductase activity in autopsied brain parts of chronic schizophrenics and controls and in vitro tryptoline formation.

We and others have shown that in vitro tryptoline (tetrahydro-beta-carboline) formation accounts for the apparent-N-methylating activity of a brain enzymatic preparation using 5-methyltetrahydrofolic acid (5-MTHF) as a cofactor and tryptamines or catecholamines as substrates. This paper demonstrates that N5,10-methylenetetrahydrofolate reductase (methylene reductase) is responsible for this in vitro tryptoline formation with human brain enzymatic preparations. Others have described a folate-responsive psychosis which was associated with markedly reduced methylene reductase activity. Therefore, we also have examined this enzymatic activity in autopsied brains from chronic schizophrenics and controls. There were no statistically significant differences between activities for schizophrenics and controls in the six brain regions studied. Thus, although it is possible that some subgroup of schizophrenics may be characterized by abnormal methylene reductase activity, there does not appear to be a general association between the two.

Animals↗