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Biomedical subjects

C Wilson

Publications and source records attributed to C Wilson.

At least 379 records · Page 21Linked to original sources

Analysis of the regions coding for transfer RNAs in Kluyveromyces lactis mitochondrial DNA.

The major regions coding for the transfer RNA genes in the mitochondrial DNA of K. lactis were studied. Twenty one, out of a supposed twenty four tRNA genes were identified and localized with respect to other mitochondrial genes. Most of the tRNA genes were found in a cluster downstream of the large ribosomal RNA gene. The order of a few groups of genes is conserved with respect to S. cerevisiae and T. glabrata. The highly diverged intergenic sequences contained a large number of guanine-cytosine clusters which frequently formed long palindromic sequences.

Base Composition↗

C-reactive protein, antiproteases and complement factors as objective markers of severity in acute pancreatitis.

In a series of patients with acute pancreatitis we have studied complement factors, antiproteases (alpha 2-macroglobulin and alpha 1-antiprotease) and C-reactive protein to determine the value of their sequential measurement in the prediction of outcome relative to clinical assessment and current multiple factor scoring systems. Complement factors were unhelpful in predicting the severity of an attack. alpha 2-Macroglobulin levels were significantly lower in complicated attacks during days 3-8 and alpha 1-antiprotease levels were significantly higher during days 4-8. C-reactive protein concentrations showed the best discrimination between mild and complicated attacks, levels rising higher and persisting for longer in complicated attacks; these differences were highly significant from day 2 (the morning after admission) to day 8. The concentrations providing the best discrimination were found to be greater than or equal to 210 mg/l for the peak C-reactive protein (on the second, third or fourth day) and greater than or equal to 120 mg/l for the C-reactive protein at the end of the first week. Analysis demonstrated both the peak or seventh-day C-reactive protein concentration to be of similar accuracy to either the Ranson or Glasgow multiple factor scoring systems and slightly better for attacks associated with gallstones. The C-reactive protein assay is simple, quick to perform, provides useful clinical information and is more likely to be of value and to be adopted into routine clinical practice than multiple factor scoring systems.

Acute Disease↗

Acute pancreatitis and pancreatic fistula formation.

The cause, management and outcome of 23 patients with a pancreatic fistula following acute pancreatitis are reviewed. Nineteen patients developed an external fistula following necrosectomy or drainage of a pancreatic abscess or pseudocyst; four of these patients died. In the 15 survivors spontaneous closure occurred in 11 cases with low output fistulae; operative intervention was needed in the four cases with high output fistulae. Four patients with internal fistulae had not undergone previous surgery; two of them had a pancreaticopleural fistula with associated pancreaticogastric fistulae, while two had pancreatic ascites. All four of these patients required surgical intervention and one died.

Abscess↗

A computer model to dynamically simulate protein folding: studies with crambin.

The current work describes a simplified representation of protein structure with uses in the simulation of protein folding. The model assumes that a protein can be represented by a freely rotating rigid chain with a single atom approximating the effect of each side chain. Potentials describing the attraction or repulsion between different types of amino acids are determined directly from the distribution of amino acids in the database of known protein structures. The optimization technique of simulated annealing has been used to dynamically sample the conformations available to this simple model, allowing the protein to evolve from an extended, random coil into a compact globular structure. Many characteristics expected of true proteins, such as the sequence-dependent formation of secondary structure, the partitioning of hydrophobic residues, and specific disulfide pairing, are reproduced by the simulation, suggesting the model may accurately simulate the folding process.

Computer Simulation↗

Rheumatoid arthritis and Proteus: a possible aetiological association.

The presence of specific anti-Proteus antibodies in active, rheumatoid arthritis (RA) patients, has been demonstrated by four different techniques: indirect bacterial agglutination, ELISA, Western blotting and immunofluorescence. Furthermore, anti-HLA-DR4 tissue typing sera have been shown to bind to Proteus microorganisms, thereby suggesting some molecular similarity or cross-reactivity between bacteria and HLA antigens. The concept is proposed that Proteus-reactive arthritis occurs during active phases of RA and tissue damage is mediated through immunological activity involving HLA antigens.

Antibodies, Bacterial↗

Application of fourth derivative absorption spectroscopy to protein quantitation during purification.

A method for protein quantitation in the presence of nonprotein cellular components is described. The method is based on measurement of two tryptophan-specific signals in the fourth derivative of the protein's ultraviolet absorption spectrum, a peak at 283 nm and a trough at 288 nm. The amplitude between these two extremes is shown to vary linearly with protein concentration for bovine serum albumin and the outer membrane vesicles of Neissera meningitidis even when these protein solutions are supplemented with enough nucleic acid to completely obscure the parent absorption spectrum of the protein. The utility of this method as an in-process assay during isolation of a protein is demonstrated by comparing estimates of protein content from fourth derivative spectroscopy with those from the Lowry assay for samples at several steps along the isolation pathway for outer membrane vesicles of N. meningitidis. The advantages and limitations of the present method are discussed.

Bacterial Outer Membrane Proteins↗

The histology of experimental pleural injury with tetracycline, empyema, and carrageenan.

Models of pleural injury were established with intrapleural tetracycline, intrapleural carrageenan, and empyema in New Zealand White rabbits to evaluate histologically the pleural inflammatory response from 3 to 90 days. Both tetracycline and empyema models produced increases in the pleural connective tissue layers both above and below the fibroelastic membrane associated with angiogenesis and lymphangiogenesis. The influx of fibroblasts from the pleural surface into acellular fibrin strands formed adhesions between the visceral and the parietal pleurae. Injury to the mesothelial cell ranged from a cuboidal transition to total desquamation with the degree of mesothelial injury associated with the amount of fibrin adherence and the propensity toward fibrosis at 90 days. Intervention to promote the resolution of pleural inflammation without fibrosis should be directed toward preservation of the mesothelial surface, removal of pleural fibrin, and inhibition of fibroblast growth and chemotaxis.

Animals↗

Knowledge about AIDS and self-reported behaviour among Zimbabwean secondary school pupils.

Knowledge about AIDS and self-reported sexual behaviour was studied among 1532 (893 male, 633 female) Zimbabwean secondary school pupils drawn from 12 schools. Most subjects knew that AIDS is fatal and incurable. However, over 40% of subjects believed that most people with AIDS in Africa are homosexual. Over 40% of respondents did not know that many HIV seropositive individuals look healthy. Nearly 40% of participants believed that HIV can be contracted from toilet seats and 54% of subjects believed that mosquitos can transmit HIV. Pupils from homes in urban areas were better informed about AIDS than were those from homes in rural areas. Forty-six percent of males and nearly 3% of females were reportedly sexually experienced. It is suggested that female under-reporting of sexual activity occurred. Nearly 16% of males reported coital experience with a prostitute. The implications of these findings for future AIDS awareness campaigns in Zimbabwe are considered.

Acquired Immunodeficiency Syndrome↗

Current management concepts for the patient with lymphedema.

The patient who is hospitalized for medical management of lymphedema presents complex issues for the nurse. Developing a care plan that will direct nursing interventions during the acute phase demands an understanding of the chronicity of the problem. The patient will require considerable teaching and support before discharge. This article provides the reader with concepts applicable to this debilitating condition.

Bandages↗

P-element-mediated enhancer detection: a versatile method to study development in Drosophila.

We generated and characterized greater than 500 Drosophila strains that carry single copies of a novel P-element enhancer detector. In the majority of the strains, the beta-galactosidase reporter gene in the P-transposon responds to nearby transcriptional regulatory sequences in the genome. A remarkable diversity of spatially and temporally regulated staining patterns is observed in embryos carrying different insertions. We selected numerous strains as markers for different embryonic organs, tissues, and cells. Many of these strains should allow the study of complex developmental processes, such as nervous system development, which have not been convenient to analyze previously. Also, we present genetic evidence that some of the detected regulatory elements control nearby Drosophila genes. In light of our results, we discuss the diversity and complexity of cis-acting regulatory elements in the genome and the general applications of the enhancer detector method for the study of Drosophila development.

Animals↗

P-element-mediated enhancer detection: an efficient method for isolating and characterizing developmentally regulated genes in Drosophila.

We describe a new approach for identifying and studying genes involved in Drosophila development. Single copies of an enhancer detector transposon, P[1ArB], have been introduced into flies at many different genomic locations. The beta-galactosidase reporter gene in this construct is influenced by a wide range of genomic transcriptional regulatory elements in its vicinity. Our results suggest that a significant proportion of these regulatory sequences are control elements of nearby Drosophila genes. These genes need not be disrupted for their regulatory elements to be identified by P[1ArB]. The P[1ArB] transposon has been designed to facilitate both rapid cloning and deletion analysis of genomic sequences into which it inserts. Therefore, the enhancer detection system is an efficient method of screening for genes primarily on the basis of their expression pattern and then rapidly analyzing those of particular interest at the molecular and genetic levels.

Animals↗

Management of gallstone pancreatitis.

The clinical course of 143 patients with gallstone pancreatitis is reviewed. Thirty-one patients (22%) had three or more positive prognostic factors on admission and 24 (77%) of these had a complicated course. Thirteen patients died, giving an overall mortality rate of 9%. Patients were divided into three groups on the basis of performance and timing of surgery. In group 1 (n = 56), surgery was undertaken during the first admission with acute pancreatitis; eight of these patients had a complicated course and three died. In group 2 (n = 40), biliary surgery was deferred to a subsequent admission; none of these patients died but 10 experienced further attacks of pancreatitis while awaiting reoperation. Group 3 patients (n = 47) did not undergo surgery; nine patients were diagnosed as having gallstone pancreatitis for the first time at autopsy, five refused operation, seven were lost to follow-up, six were dealt with by endoscopic sphincterotomy, and in 20 cases surgery was not considered appropriate because of general debility or advanced age. Despite the zero mortality rate in group 2, it is advocated that biliary surgery be carried out during the index hospital admission. Endoscopic sphincterotomy can now be considered as an alternative to cholecystectomy and duct clearance in the elderly and unfit, and may be used as a preliminary manoeuvre when severe acute pancreatitis fails to settle promptly on conservative management.

Acute Disease↗

Inhibition by sulphonylureas of vasorelaxation induced by K+ channel activators in vitro.

1. The effects of the sulphonylureas glibenclamide, glipizide and tolbutamide on relaxant responses to the K+ channel activator, cromakalim (BRL 34915), were investigated in rabbit isolated mesenteric artery. The interaction between glibenclamide and pinacidil, another K+ channel activator, was also studied. 2. Glibenclamide produced progressive parallel shifts to the right of the cromakalim and pinacidil concentration-response curves. The calculated pA2 values were 7.16 +/- 0.03 against cromakalim and 6.66 +/- 0.05 against pinacidil. 3. Glipizide and tolbutamide also produced parallel shifts to the right of the cromakalim concentration-response curve to yield pA2 values of 5.59 and 3.98 respectively. 4. Glibenclamide had little inhibitory effect upon vasorelaxant responses to the Ca2+ channel blocker, nifedipine. 5. The results suggest that cromakalim and pinacidil activate an ATP-sensitive K+ channel in vascular smooth muscle which may differ from that of the pancreatic beta-cells.

Animals↗

Inhibition by glibenclamide of the vasorelaxant action of cromakalim in the rat.

1. In rat isolated thoracic aortic rings pre-contracted with noradrenaline (10(-6) M), cromakalim (3 x 10(-7)-3 x 10(-5) M) produced concentration-related relaxation. This effect was progressively inhibited by increasing concentrations of the anti-diabetic sulphonylurea drug, glibenclamide (10(-6)-10(-5) M). 2. In rat isolated portal veins, cromakalim (3 x 10(-8)-10(-6) M) produced concentration-related inhibition of the spontaneous contractive activity and glibenclamide (3 x 10(-7)-3 x 10(-6) M) prevented this inhibitory action in a concentration-dependent manner. 3. In both rat aortic rings and portal veins, cromakalim (10(-5) M) stimulated 86Rb efflux. Prior exposure to glibenclamide (10(-7)-10(-6) M) produced a concentration-related inhibition of this response. 4. In conscious rats, cromakalim, 0.075 mg kg-1 i.v., produced a rapid and sustained fall in arterial blood pressure which was not influenced by pretreatment (2 h) with a large oral dose of glibenclamide (100 mg kg-1). 5. In conscious rats, the hypotensive action of cromakalim, 0.075 mg kg-1 i.v., was abolished by pretreatment (30 min) with glibenclamide, 20 mg kg-1, given by the intravenous route. 6. The results suggest that the vasorelaxant and hypotensive actions of cromakalim involve a K+ channel which can be inhibited by glibenclamide, but which may be distinct from the ATP-sensitive K+ channel of the pancreatic beta-cell.

Animals↗