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Biomedical subjects

D C Watson

Publications and source records attributed to D C Watson.

At least 55 records · Page 3Linked to original sources
PubMed1992

Protection of mice against Salmonella typhimurium with an O-specific polysaccharide-protein conjugate vaccine.

Serious infections with salmonellae remain a threat in many human populations. Despite extensive study of salmonella infections in animals and clinical experience with killed cellular vaccines, there are no vaccines against serotypes other than Salmonella typhi licensed for human use. Serum antibodies to the O-specific polysaccharide (O-SP) of salmonellae protect mice against invasive infection. In order to render it immunogenic, we have conjugated the O-SP of Salmonella typhimurium to carrier proteins by various schemes. O-SP conjugated to tetanus toxoid (O-SP-TT) elicited antibodies in outbred mice after three subcutaneous injections without adjuvant. The O-SP alone elicited no detectable antibody. The antibody response to O-SP-TT was boosted by successive doses and consisted of immunoglobulin G (IgG) and IgM. Most mice only produced antibodies specific for the abequose (O:4 factor) region of the O-SP. Occasional animals also produced antibodies to the core oligosaccharide. Immunized mice were protected against intraperitoneal challenge with S. typhimurium, demonstrating a 160-fold increase in the 50% lethal dose. Passive immunization with conjugate-induced IgM or IgG also protected against challenge. These results indicate that an O-SP-TT conjugate, when given by a route and formulation acceptable for human use, protects mice against challenge with S. typhimurium.

Animals↗
PubMed1992

The practice of cardiothoracic surgeons in the perioperative staging of non-small cell lung cancer.

BACKGROUND: The treatment and prognosis of non-small cell lung cancer, and assessment of the results of treatment, depend on accurate perioperative staging. The extent to which this is carried out in the United Kingdom is unknown. METHODS: A postal questionnaire survey was undertaken in 1990 to determine the perioperative staging practices of cardiothoracic surgeons in the United Kingdom. RESULTS: Replies from 77 surgeons, who between them performed about 4833 pulmonary resections a year for lung cancer, were analysed. Forty four per cent of surgeons, operating on 43% of the patients, do not perform computed tomography of the thorax or mediastinal exploration before surgery. They may therefore embark on a thoracotomy for stage III disease. At thoracotomy 45% of surgeons, operating on 40% of patients, do not sample macroscopically normal lymph nodes. They may therefore understage cases as N0/N1 when there is at least microscopic disease in mediastinal lymph nodes. CONCLUSIONS: The staging of lung cancer in the United Kingdom in 1990 appears in many instances to be inadequate. There should be a more organised approach to perioperative staging so that prognosis may be assessed and comparisons between groups of patients can be made.

Carcinoma, Non-Small-Cell Lung↗
PubMed1991

The amino acid sequences of jacalin and the Maclura pomifera agglutinin.

Amino acid sequences for the alpha-chains of the Moraceae lectins, jacalin and Maclura pomifera agglutinin, were determined by protein sequencing. Both are 133 residues long and contain several genetically variant positions; the overall homology is 85%. A possible site for the known glycopeptide of jacalin was located. The alpha-chains have a conserved tryptophan residue that may be part of the binding-site.

Amino Acid Sequence↗
PubMed1991

The amino acid sequence of peanut agglutinin.

The amino acid sequence of peanut (Arachis hypogaea) agglutinin was determined from three major fragments obtained by mild acid cleavage at Asp-Pro peptide bonds. The sequence of 236 amino acids has residues identical to those that form the metal-binding site and the hydrophobic pocket in concanavalin A and other lectins, although the overall similarity is only 42%. In the segments of peanut agglutinin that correspond to the four loops that form the carbohydrate-binding site in concanavalin A and favin, several central residues are homologous, while others show changes to smaller side chains, such as Tyr----Gly. The carbohydrate-binding site of peanut agglutinin may therefore have a similar peptide-backbone architecture, but form a considerably more open cleft.

Amino Acid Sequence↗
PubMed1991

Cloning, sequencing and expression of the Schwanniomyces occidentalis NADP-dependent glutamate dehydrogenase gene.

The cloned NADP-specific glutamate dehydrogenase (GDH) genes of Aspergillus nidulans (gdhA) and Neurospora crassa (am) have been shown to hybridize under reduced stringency conditions to genomic sequences of the yeast Schwanniomyces occidentalis. Using 5' and 3' gene-specific probes, a unique 5.1 kb BclI restriction fragment that encompasses the entire Schwanniomyces sequence has been identified. A recombinant clone bearing the unique BclI fragment has been isolated from a pool of enriched clones in the yeast/E. coli shuttle vector pWH5 by colony hybridization. The identity of the plasmid clone was confirmed by functional complementation of the Saccharomyces cerevisiae gdh-1 mutation. The nucleotide sequence of the Schw. occidentalis GDH gene, which consists of 1380 nucleotides in a continuous reading frame of 459 amino acids, has been determined. The predicted amino acid sequence shows considerable homology with GDH proteins from other fungi and significant homology with all other available GDH sequences.

Amino Acid Sequence↗
PubMed1991

Atrioventricular septal defect repair in infants.

From September 1984 through August 1989, 33 consecutive infants (mean age, 9 months; 13 male) received a single-stage intracardiac repair of complete atrioventricular septal defect. Preoperative evaluation of valvar morphology and function involved echocardiograms in 21% (7/33) and echocardiograms with cineangiograms in 79% (26/33). All infants operated on were included in the analysis. Patients with other complicating abnormalities were not excluded. All operations used a two-patch technique for closure of the atrioventricular septal defect in association with mitral valve repair. The newly formed septal leaflet of the mitral valve was repaired using unpledgeted interrupted sutures. Preoperative and postoperative echocardiograms were used to evaluate mitral valve regurgitation and left ventricular dysfunction as mild, moderate, or severe. The 30-day mortality was 6% (2/33). Follow-up ranged from 1 month to 60 months. Postoperative mitral valve insufficiency was mild in 84% versus 6% preoperatively, moderate in 3% versus 52% preoperatively, and severe in 13% versus 42% preoperatively. Mitral valve dysfunction necessitating reoperation occurred in 6% (2/31). Mitral valve function postoperatively was improved compared with preoperatively (p less than 0.001). The low 30-day operative mortality and the excellent late postoperative valvar function demonstrate the value of single-stage two-patch repair of atrioventricular septal defect early in life.

Congenital Abnormalities↗
PubMed1991

Mycobacterium paratuberculosis antigen D: characterization and evidence that it is a bacterioferritin.

By using a combination of agarose and polyacrylamide gel electrophoresis, Mycobacterium paratuberculosis antigen D was resolved from a crude sonicated preparation of the organism and characterized as a component with a molecular mass of approximately 400,000 Da. While this component was composed mainly of protein, with unusually high proportions of glutamic acid and leucine, it was resistant to digestion with a number of proteolytic enzymes. Structural detail revealed by electron microscopy, amino acid sequence data, and the demonstration of a Soret band in its absorption spectrum indicated that antigen D was similar to an Escherichia coli bacterioferritin.

Amino Acid Sequence↗
PubMed1991

Chromatographic purification and characterization of antigens A and D from Mycobacterium paratuberculosis and their use in enzyme-linked immunosorbent assays for diagnosis of paratuberculosis in sheep.

The protein antigens A and D were purified from culture filtrates and sonic extracts of laboratory strains of Mycobacterium paratuberculosis by salt precipitation and chromatography. The characterization of antigen A is shown here, and both antigens were evaluated along with lipoarabinomannan antigen in indirect enzyme-linked immunosorbent assays (ELISA) for the serodiagnosis of ovine paratuberculosis. After anion-exchange (DEAE-5PW) and hydrophobic (phenyl-5PW) chromatography using high-performance liquid chromatography, antigen A showed a prominant band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) at 31 kDa with small amounts of low-molecular-mass proteins but with no evidence of antigen D. A single precipitin arc was evident with purified antigen A in crossed immunoelectrophoresis. The determination of the N-terminal amino acid sequence showed a high degree of homology between the 31-kDa component of antigen A and antigens of the BCG85 complex of Mycobacterium bovis BCG, a total of 24 of 26 residues being identical to those of BCG85C. A prominant SDS-PAGE band at 400 kDa and a single crossed-immunoelectrophoresis arc was also evident for antigen D after gel filtration (Sephacryl S-200), anion-exchange (DEAE-Sephacel), and concanavalin A-Sepharose affinity chromatography. By ELISA, purified antigen A detected antibody in the sera of 18 of 22 paratuberculosis-infected sheep (82% sensitivity), whereas the purified antigen D detected antibody in all 22 infected animals (100% sensitivity). Combined ELISA results showed increased specificity with some loss in sensitivity.

Amino Acid Sequence↗
PubMed1990

The amino acid sequence of chymopapain from Carica papaya.

Chymopapain is a polypeptide of 218 amino acid residues. It has considerable structural similarity with papain and papaya proteinase omega, including conservation of the catalytic site and of the disulphide bonding. Chymopapain is like papaya proteinase omega in carrying four extra residues between papain positions 168 and 169, but differs from both papaya proteinases in the composition of its S2 subsite, as well as in having a second thiol group, Cys-117. Some evidence for the amino acid sequence of chymopapain has been deposited as Supplementary Publication SUP 50153 (12 pages) at the British Library Document Supply Centre, Boston Spa., Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1990) 265, 5. The information comprises Supplement Tables 1-4, which contain, in order, amino acid compositions of peptides from tryptic, peptic, CNBr and mild acid cleavages, Supplement Fig. 1, showing re-fractionation of selected peaks from Fig. 2 of the main paper. Supplement Fig. 2, showing cation-exchange chromatography of the earliest-eluted peak of Fig. 3 of the main paper, Supplement Fig. 3, showing reverse-phase h.p.l.c. of the later-eluted peak from Fig. 3 of the main paper, and Supplement Fig. 4, showing the separation of peptides after mild acid hydrolysis of CNBr-cleavage fragment CB3.

Amino Acid Sequence↗
PubMed1990

Tension hydropneumothorax as delayed presentation of traumatic rupture of the diaphragm.

Diaphragmatic rupture due to blunt trauma is well recognised though uncommon. Most cases are diagnosed at the time of injury, but a proportion remain undiagnosed, only to present some months or even years later. This "delayed" group can present in a number of ways, including chronic abdominal and chest problems or an acute crisis. Herniation of abdominal viscera is the most common sequel, with strangulation and gangrene as the most serious complication. This paper reports a case of delayed presentation of diaphragmatic rupture and herniation presenting as tension hydropneumothorax due to small bowel perforation. A short discussion addresses the problems in diagnosis of this condition. We believe this to be the first reported case of perforated small bowel leading to tension hydropneumothorax.

Barium Sulfate↗
PubMed1990

Molecular cloning, characterization, and expression of the Tipula iridescent virus capsid gene.

The capsid protein is the major structural component of the icosahedral Tipula iridescent virus (TIV) that replicates in cytoplasmic inclusion bodies of insect cells. TIV capsid protein purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was digested with trypsin and fractionated by reverse-phase high-pressure liquid chromatography. A mixed oligonucleotide constructed from the amino acid sequence of a capsid tryptic peptide was used for the identification and cloning of the corresponding gene. The single-copy capsid gene, located on a 2.47-kilobase-pair HindIII TIV genomic fragment, codes for a 464-amino-acid protein (50,831 daltons) with a predicted pI of 6.34. Analysis of total RNA from infected Estigmene acrea cells indicated that the 1.8-kilobase capsid transcript was maximally produced between 14 and 24 h after infection. Transcript mapping by primer extension indicated that the RNA start site was in the A+T-rich TGCTACTAAT sequence, 19 nucleotides upstream from the first ATG codon of the capsid open reading frame. Expression of the TIV capsid protein in infected E. acrea cells was demonstrated by in vivo labeling of total proteins with [35S]methionine, using anti-capsid antiserum as the probe. Capsid protein was also expressed in Escherichia coli cells by using a pUC19 plasmid containing a lacZ-capsid gene fusion.

Amino Acid Sequence↗
PubMed1989

Homology of the D-galactose-specific lectins from Artocarpus integrifolia and Maclura pomifera and the role of an unusual small polypeptide subunit.

The Maclura pomifera agglutinin (MPA) was purified by affinity chromatography from a seed extract and its properties were compared with those of the Artocarpus integrifolia lectin, jacalin. Reverse-phase high-performance liquid chromatography showed both proteins had multiple forms of a small approximately 20-residue polypeptide chain in addition to the major 12,000 Mr subunit. The amino acid sequences of the small chains and the N-terminal sequences of the large subunits showed considerable similarity between the two proteins, approximately 60% identical residues. The homology of the proteins was confirmed by the similarity of their circular dichroism and fluorescence emission spectra. MPA showed much greater spectral changes upon binding methyl alpha-D-galactoside, suggesting it has complete activity rather than the partial activity found for jacalin. The binding of methyl alpha-D-galactoside by MPA was measured by fluorescence titration; the KA was 1.9 X 10(4) M-1 compared to 3.4 X 10(4) M-1 for jacalin. MPA also precipitated human IgA1 in the same manner as jacalin. The spectra indicate the involvement of tryptophan and tyrosine residues in the binding site of these lectins. Since a tryptophan residue is conserved in all the small subunits, they may form part of the binding site.

Amino Acid Sequence↗
PubMed1989

Construction of an aortic homograft conduit for right ventricle to pulmonary artery continuity.

Over the past decade the aortic homograft has become the extracardiac conduit of choice for repair of many congenital cardiac defects. Anastomosis of the homograft annulus to the right ventricle may distort the valve and render it incompetent. Prosthetic tube grafts have been used to bridge the right ventricle and distal homograft. We propose and have use successfully a method for establishing right ventricle to pulmonary artery continuity that is free of prosthetic materials, is technically simple, and places the homograft valve in the hilum, away from the distorting right ventricle free wall.

Aorta↗
PubMed1989

Increased levels of vaccenic acid in bronchogenic carcinoma tissue.

Employing capillary gas liquid chromatography the levels of palmitic, palmitoleic, stearic, oleic, cis-vaccenic, linoleic, arachidonic and docosahexaenoic acids were measured in lung tissue and lung tumours from 28 patients undergoing surgery for bronchogenic carcinoma. There were significant increases in the majority of fatty acids in tumour tissue compared to normal tissue when the results were expressed in absolute units. However, when the relative changes in fatty acid concentration were studied, the most consistent findings were a significant rise in vaccenic acid and a fall in palmitic acid in tumour tissue compared to normal tissue. This change in the vaccenic:palmitic acid ratio may reflect specific changes in fatty acid metabolism in bronchogenic carcinoma tissue involving a delta-9 desaturase.

Adult↗
PubMed1989

Chemotherapy plus adjuvant surgery for local small cell lung cancer.

Eight patients with local Stage II (T2N1) and III (T3N0, T3N1, T2N2) small cell lung cancer received combination chemotherapy prior to elective surgery to assess the effectiveness of such a regimen in improving operability, preventing local relapse and extending survival. The regimen was well tolerated and prevented local relapse. However, the median time to recurrence of disease was 10 months and the median survival time 13 months, results which are similar to those achieved with chemotherapy and radiotherapy. Distant metastases, particularly in the brain, occurred predictably indicating that successful adjuvant surgery, despite preventing local relapse, may not afford additional survival benefit with currently available drug regimens.

Adult↗
PubMed1989

Does open lung biopsy affect treatment in patients with diffuse pulmonary infiltrates?

The decision to perform open lung biopsy in the evaluation of a diffuse pulmonary infiltrate is based on the probability that this examination will yield specific information that may lead to a change in treatment. The role of this procedure remains controversial and many clinicians are reluctant to allow this invasive procedure without assurances that results will lead to a change in therapy for a significant number. To evaluate the impact of open lung biopsy on diagnosis and treatment of diffuse pulmonary infiltrates, we conducted a retrospective review of 61 patients undergoing this procedure at three university-affiliated hospitals during a recent 7-year period. There were 37 men and 24 women; average age was 57 years. Biopsy yielded a specific diagnosis in 21 (34%) patients and a change in therapy in 33 (54%) patients. A complication developed in 11 (18%) patients, directly related to the biopsy procedure in six (10%). Eight patients died. The immune status in 22 (36%) patients was compromised. A specific diagnosis was obtained in 13 (59%) immunocompromised patients and a change in therapy occurred in 17 (77%) of these patients after biopsy. A specific diagnosis was obtained in only eight (21%) of the 39 noncompromised patients and therapy was changed in 16 (41%) patients in this group (p less than 0.02 compromised versus noncompromised). Morbidity and mortality were not significantly different between the two groups. A nonspecific diagnosis led to a change in therapy as frequently as a specific diagnosis in both compromised and noncompromised groups. Open lung biopsy in the patient with a diffuse pulmonary infiltrate is an accurate diagnostic tool and frequently leads to a change in patient treatment. The procedure can be performed with acceptable morbidity and mortality in immunocompromised and noncompromised patients.

Adult↗