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J Dawson

Publications and source records attributed to J Dawson.

At least 55 records · Page 3Linked to original sources
PubMed2000

In vivo measurement of colonic butyrate metabolism in patients with quiescent ulcerative colitis.

BACKGROUND: Butyrate, a short chain fatty acid produced by bacterial fermentation, is a major fuel source for the colonocyte. In vitro work has shown that ulcerative colitis may be characterised by a metabolic defect in colonocyte butyrate oxidation. AIMS: To investigate the rate of metabolism of rectally administered butyrate in patients with quiescent colitis. METHODS: [1-(13)C]-butyrate enemas were administered to 11 patients with long standing quiescent ulcerative colitis and to 10 control patients. The rate of production of (13)CO(2) in exhaled breath over four hours was measured by isotope ratio mass spectrometry combined with indirect calorimetry in order to measure CO(2) production. This allowed calculation of the patients' resting energy expenditure and respiratory quotient. RESULTS: Over a four hour period, 325 (SEM 21) micromol (13)CO(2) was recovered in breath samples from the colitis group compared with 322 (17) micromol from the control group (NS). The respiratory quotient of the colitic group was significantly lower than that of the control group. CONCLUSION: There was no difference in the rate of metabolism of butyrate between the two groups. It is unlikely that there is a primary metabolic defect of butyrate metabolism in patients with quiescent ulcerative colitis.

Adult↗
PubMed2000

Immunohistochemical and in situ hybridization studies of influenza A virus infection in human lungs.

Influenza viruses are responsible for acute febrile respiratory disease. When deaths occur, definitive diagnosis requires viral isolation because no characteristic viral inclusions are seen. We examined the distribution of influenza A virus in tissues from 8 patients with fatal infection using 2 immunohistochemical assays (monoclonal antibodies to nucleoprotein [NP] and hemagglutinin [HA]) and 2 in situ hybridization (ISH) assays (digoxigenin-labeled probes that hybridized to HA and NP genes). Five patients had prominent bronchitis; by immunohistochemical assay, influenza A staining was present focally in the epithelium of larger bronchi (intact and detached necrotic cells) and in rare interstitial cells. The anti-NP antibody stained primarily cell nuclei, and the anti-HA antibody stained mainly the cytoplasm. In 4 of these cases, nucleic acids (ISH) were identified in the same areas. Three patients had lymphohistiocytic alveolitis and showed no immunohistochemical or ISH staining. Both techniques were useful for detection of influenza virus antigens and nucleic acids in formalin-fixed paraffin-embedded tissues and can enable further understanding of fatal influenza A virus infections in humans.

Adolescent↗
PubMed2000

Experience with pneumonia in acutely burned patients requiring ventilator support.

Acutely burned patients requiring ventilatory support who developed pneumonia while in the hospital were retrospectively reviewed. The Centers for Disease Control and Prevention (CDC) clinical criteria for pneumonia are based on clinical findings, radiographic findings, and culture data. During an 18-month period, 784 burn patients were admitted. Of these, 145 (18.5%) were placed on ventilators for at least 1 day. Fifty-three (36.6%) patients on ventilators developed acute pneumonia based on CDC criteria. Identification of causative organisms was based on positive cultures from blood or endotracheal aspiration within 3 days of the diagnosis of pneumonia. Thirty-nine patients were diagnosed as having inhalation injury. Forty-seven patients were placed on ventilators before or on the day of admission. Ages ranged from 2 to 82 years (mean, 39). Burn size ranged from 2 to 85 per cent (mean, 29.7%) of total body surface area. The total number of ventilator days was 1310 for the 53 patients, with a mean of 27.7 days. Ten patients had positive blood cultures during the period in which pneumonia was present. Thirty-one different organisms were recovered from blood or tracheal aspirates. The most commonly recovered organism was Pseudomonas aeruginosa. In 30 incidences, polymicrobial cultures were encountered. Initiation of appropriate antimicrobial therapy was begun on the basis of clinical impression and current burn unit experience and revised on the basis of the culture data. Of the 53 patients, 13 (25.5%) died, all while still on ventilators. The other 40 patients survived. Thirty-four were weaned off their ventilators, and 6 were transferred while still on ventilator support.

Adult↗
PubMed2000

Experience with the insertion of vena caval filters in acutely burned patients.

The use of inferior vena caval filters in patients at high risk of pulmonary emboli is a standard practice in many types of patients. The usefulness of such filters in acutely burned patients has yet to be established. Twenty inferior vena caval filters were inserted in burn patients. Five were inserted because of preexisting thromboembolic disease. Fifteen were placed prophylactically because of high-risk states, including prolonged immobilization, old age, bleeding problems, and obesity. There were no complications due to filter insertion. No postinsertion emboli were recognized. There were no cases of postinsertion thrombophlebitis. In this small series, the procedure appears to be effective and safe.

Acute Disease↗
PubMed2000

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Journal Article↗
PubMed1999

High-resolution three-dimensional magnetic resonance imaging for the investigation of knee joint damage during the time course of antigen-induced arthritis in rabbits.

OBJECTIVE: To investigate the efficacy of high-resolution 3-dimensional magnetic resonance imaging (3-D MRI) with gadolinium contrast agent enhancement in monitoring soft tissue and hard tissue changes during the course of antigen-induced arthritis in rabbits, comparing the images with the final histologic outcome. METHODS: Arthritis was induced by intraarticular injection of methylated bovine serum albumin into rabbits that had been presensitized to the same antigen. MRI was carried out before and on predetermined days after the onset of inflammatory arthritis, up to day 60. At each time point, 3-D gradient-echo images were acquired. At the end of the study, the knee joints were processed for histologic study. RESULTS: Time-related inflammatory changes, such as soft tissue swelling, were seen initially, followed by a reduction in the acute swelling and a progression to hard tissue damage at later time points. The final 3-D data sets were then used to compare MR images with the histologic sections. The knee joints were sectioned in the sagittal, coronal, or transverse direction. Comparison of final images and histologic features at day 60 enabled a more complete interpretation of the MR images, allowing direct correlation of joint damage observed using the MRI technique with that seen in the final histologic analysis. CONCLUSION: Qualitative information derived from MR images correlated extremely well with histologic findings. These results indicate the great potential of MRI for noninvasive investigation of drug effects in this model of arthritis.

Animals↗
PubMed1999

National epidemiology of mycoses survey (NEMIS): variations in rates of bloodstream infections due to Candida species in seven surgical intensive care units and six neonatal intensive care units.

Candida species are the fourth most frequent cause of nosocomial bloodstream infections, and 25%-50% occur in critical care units. During an 18-month prospective study period, all patients admitted for > or = 72 hours to the surgical (SICUs) or neonatal intensive care units (NICUs) at each of the participant institutions were followed daily. Among 4,276 patients admitted to the seven SICUs in six centers, there were 42 nosocomial bloodstream infections due to Candida species (9.8/1,000 admissions; 0.99/1,000 patient-days). Of 2,847 babies admitted to the six NICUs, 35 acquired a nosocomial bloodstream infection due to Candida species (12.3/1,000 admissions; 0.64/1,000 patient-days). The following were the most commonly isolated Candida species causing bloodstream infections in the SICU: Candida albicans, 48%; Candida glabrata, 24%; Candida tropicalis, 19%; Candida parapsilosis, 7%; Candida species not otherwise specified, 2%. In the NICU the distribution was as follows: C. albicans, 63%; C. glabrata, 6%; C. parapsilosis, 29%; other, 3%. Of the patients, 30%-50% developed incidental stool colonization, 23% of SICU patients developed incidental urine colonization, and one-third of SICU health care workers' hands were positive for Candida species.

Candidiasis↗
PubMed1999

Effects of soluble interleukin-1 type II receptor on rabbit antigen-induced arthritis: clinical, biochemical and histological assessment.

OBJECTIVES: To investigate the effects of soluble interleukin-1 (IL-1) type II receptor (sIL-1RII) on a number of clinical, biochemical and histological parameters in rabbit antigen-induced arthritis. METHODS: Arthritis was induced by intra-articular injection of methylated bovine serum albumin (mBSA) into rabbits pre-sensitized to the same antigen. An initial i.v. bolus of sIL-1RII was administered, followed by s.c. mini-pump dosing for 14 days, starting at the time of the arthritis induction. Animals received vehicle (saline 500 microl + 5 microl/h), low-dose sIL-1RII (13.4 microg + 1.34 microg/h) or high-dose sIL-1RII (40.2 microg + 4.02 microg/h). RESULTS: Marked, dose-related inhibition of joint diameter, plasma prostaglandin E2 (PGE2), and synovial fluid IL-1alpha and IL-1beta concentrations were seen after administration of sIL-1RII. However, synovial fluid PGE2 concentrations and synovial fluid cell counts were not affected. A significant inhibitory effect was also seen histologically on soft-tissue swelling and joint damage with high-dose sIL-1RII. CONCLUSIONS: These results demonstrate that IL-1 plays an important role in the pathogenesis of rabbit antigen-induced arthritis, thus confirming it as an excellent animal model with respect to evaluating anti-cytokine therapies for rheumatoid arthritis.

Animals↗
PubMed1999

Evaluation of the circulation of reconstructive flaps using laser-induced fluorescence of indocyanine green.

A new method for evaluating the circulation in surgical flaps using laser-induced fluorescence of indocyanine green (ICG) images is reported. In clinical trials the authors found that ICG imaging demonstrated good circulation accurately in 16 of 21 flaps with no clinical manifestations of compromised circulation. In 3 patients in whom partial discoloration and cyanosis of the flaps were visible, the dye study indicated poor circulation in the identical areas. In 2 other patients in whom flaps appeared clinically satisfactory, the flaps were shown by ICG imaging to have greatly compromised circulation. In a patient in whom the flap was left in place, slough of almost the entire flap resulted. Another flap with questionable circulation was returned to its original location, where it healed. Thus, while it is a still a new approach and under continual evaluation, the use of ICG fluorescence shows promise as a valuable adjunct to current methods of flap evaluation.

Coloring Agents↗
PubMed1999

Reconstruction of disruption of the abdominal wall in burn patients.

Two patients with extensive destruction of the full thickness of the abdominal wall and associated intra-abdominal injuries were encountered. One case resulted from burns to a patient pinned under an automobile in contact with the muffler; the other was injured as a result of penetration of the abdominal wall by a railroad coupling and was also burned in an associated welding accident at the same time. Extensive staged debridement and repair of intra-abdominal injuries in several procedures were required in case 1. Closure was eventually achieved with serial applications of mesh and split-thickness autografting. In case 2, an initial attempt at flap closure failed. Coverage initially was obtained with silicone mesh followed by split-thickness grafting. We report successful management of two of these difficult reconstructive challenges.

Abdominal Injuries↗
PubMed1999

Circulating antibodies to Saccharomyces cerevisiae (bakers'/brewers' yeast) in gastrointestinal disease.

AIM: To measure circulating antibodies to yeast organisms that could be used to characterise the yeast specific immune response in gastrointestinal disease. METHODS: A quantitative, isotype specific enzyme linked immunosorbent assay was developed to measure circulating antibodies to an aqueous extract of Saccharomyces cerevisiae (sacc). Comparisons of specific antibody concentrations were made between 224 healthy controls and 51 patients with Crohn's disease, 41 with ulcerative colitis, 24 with indeterminate colitis, 23 with chronic liver disease, 17 with coeliac disease, and seven with irritable bowel syndrome. Additional comparisons were made between Crohn's disease and ulcerative colitis patients. Within the Crohn's disease group, the dependence of antibody levels on several clinical variables was assessed. RESULTS: IgG and IgA anti-sacc antibodies were significantly raised in Crohn's disease. IgG antibodies were also raised in patients with chronic liver disease. Among patients with Crohn's disease, IgG antibody concentrations were higher in those with serum alpha 1 acid glycoprotein (AAG) above the normal range and there was a strong trend towards increased IgG anti-sacc in the presence of small bowel disease, whereas IgA anti-sacc correlated positively with disease duration. No differences were detected according to whether patients were taking steroids. Neither the Crohn's disease nor the chronic liver disease group differed from normal subjects in respect of IgG antibodies to bovine milk casein. On linear regression analysis of complete data from 39 Crohn's disease patients, AAG was found to be a significant predictor of both IgG and IgA antibodies, and male sex and disease duration to be additional predictors of IgA antibodies. There was a significant difference in IgG antibodies between Crohn's disease and ulcerative colitis. CONCLUSIONS: Raised antibodies to yeast, although not completely specific for Crohn's disease, may have a future role in diagnosis. The assays described here could be used to address this question in the context of a prospective study.

Adult↗
PubMed1999

The assessment of shoulder instability. The development and validation of a questionnaire.

We have developed a 12-item questionnaire for completion by patients presenting with shoulder instability. A prospective study of 92 patients was undertaken involving two assessments, approximately six months apart, performed in an outpatient department. Each patient completed the new questionnaire and the SF36 form. An orthopaedic surgeon completed the Constant shoulder score and the Rowe assessment. The new questionnaire and the Rowe clinical score each achieved a large standardised effect size (> or = 0.8) and compared favourably with relevant items on the SF36. By contrast, the Constant score barely registered any effect, confirming that it may be relatively insensitive to changes in clinical status for this particular condition. The questionnaire provides a measurement of outcome for shoulder instability which is short, practical, reliable, valid and sensitive to changes of clinical importance.

Adolescent↗
PubMed1999

A microtiter-plate assay of nitric oxide synthase activity.

We describe here a microtiter-plate assay for measuring nitric oxide synthase (NOS) activity by utilizing the spectral shift in optical absorbence between the wavelengths 405 and 420 nm on conversion of oxyhemoglobin to methemoglobin by nitric oxide (NO). This is a high-throughput assay permitting 96 or 384 simultaneous kinetic measurements and is ideal for the study of NOS inhibitors and their time dependence. It is also possible to measure enzyme rates under different conditions simultaneously for the study of the cofactor and substrate dependence of NOS preparations. The assay requires approximately 10 pmol/min of NOS activity to achieve a-l moD/min rate.

Animals↗
PubMed1999

Randomized study of online vaccine reminders in adult primary care.

Online immunization reminders were implemented in an adult medicine setting in which all immunization history, vaccine ordering and charting were required online. Physicians were randomized to one of two arms in a cross-over design. Each arm was shown online recommendations for vaccines indicated by nationally accepted guidelines either during the first or during the second part of the study period. The main purpose of the study was to assess the impact of reminders on correct decisions related to prescribing vaccines. Online reminders had the following impact on physician behavior: 1) Physicians used the application almost 3 times as often when shown reminders. 2) Physicians in the reminder group were 27% less likely to order a vaccine in the reminder group (P- value 0.0005). 3) Compliance with guidelines was improved significantly for Tetanus and for Hepatitis B in several analyses. No such effects were found for Pneumoccocal, Measles, or Influenza vaccines.

Adult↗
PubMed1998

A novel transforming growth factor beta2 antisense transcript in mammalian lung.

Transforming growth factor (TGF) beta2 gene expression was examined in murine, rat and human lung by in situ hybridization with riboprobes. Hybridization signal was observed in a variety of cells with the sense probe, and Northern-blot analysis with this probe demonstrated the presence of a novel 3.5 kb transcript. This first report suggesting the existance of a natural TGFbeta2 antisense transcript raises the possibility that such a transcript may play a role in regulating TGFbeta2 production.

Animals↗