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Biomedical subjects

J Turner

Publications and source records attributed to J Turner.

At least 145 records · Page 8Linked to original sources
PubMed1997

Community structure and the interplay between interspecific infection and competition.

Our motivation is the need to understand how two different interactions between species-shared infection and interspecific competition-combine to determine community structure. We introduce a proto-typical model of two hosts sharing a pathogen and also competing directly. We discuss forces of infection, forces of competition and invasion criteria and their relevance to long-term outcomes and community structure. To understand their interplay, we consider first purely competitive and second purely infective interactions. We then investigate our full model to establish how the two forces combine and how the combination and related invasion criteria determine community structure. The forces of infection and competition do not merely add; there is a synergetic resistance to invasion. Using generalised invasion criteria and subsidiary conditions for the feasibility and stability of uninfected coexistence, we classify long-term outcomes. We distinguish two main routes to three-species coexistence. In the first, two host species, each of which would not alone support the pathogen, support it jointly if interspecific competition is relatively weak, interspecific infection strong. In the second, at least one host species would alone support the pathogen and both are invadable by the other, but subsidiary conditions yield two cases. In one, infected coexistence results when the two hosts would coexist stably purely competitively and at sufficiently high densities to support the pathogen jointly. Thus coexistence is promoted by weak interspecific competition but there is a tension between weak interspecific infection favouring invadability and strong interspecific infection promoting pathogen survival. In the other, infected coexistence results when the two hosts would not coexist in the absence of the pathogen. This pathogen-mediated host coexistence is expected where there is strong intraspecific infection (lowering densities) and weak interspecific infection (favouring invadibility) as necessary. Results are compared with previous work and apparent competition and resource- and transmission-mediated coexistence are discussed.

Animals↗
PubMed1997

Intensive care for people with serious mental illness.

This article describes the development of a psychiatric 'intensive care' service for men and women with serious or enduring forms of psychotic disorder. The authors suggest that such a residential therapeutic service may be an essential part of the development of community care for the most vulnerable people served by mental health services.

Critical Care↗
PubMed1997

Expression of ICAM-1 enhances in vivo lymphocyte adhesion in a murine fibrosarcoma.

BACKGROUND AND OBJECTIVES: ICAM-1 is essential for lymphocyte-endothelial cell interactions. We have demonstrated that increased expression of ICAM-1 in tumors results in an enhanced response to adoptive immunotherapy. We undertook this study to determine whether increased expression of ICAM-1 results in increased lymphocyte adhesion in vivo. METHODS: Parental MCA-105 tumor cells were cotransfected with ICAM-1 and the NeoR plasmid. A neomycin resistant clone (Cl149) was selected and increased expression of ICAM-1 confirmed by FACS analysis. Tumor fragments (MCA-105 or Cl149) were placed in a dorsal skin-fold chamber on day 0 in C57BL/6 mice. Lymphocytes were fluorescently labeled using 0.5% acridine orange and activity recorded on videotape at 700x magnification. Lymphocyte activity was quantitated over 30 second intervals in postcapillary venules as either passing or rolling/sticking (R/S). The % R/S was calculated for each category and evaluated using chi 2 analysis. RESULTS: Whereas 38% of lymphocytes were classified as R/S in normal tissue, 32% were classified as R/S (P > .05) in the MCA-105 tumor. However, in the ICAM-1 transfected CL149, there was significantly greater R/S at 53% (P < .05). CONCLUSIONS: These data demonstrate increased lymphocyte adhesion in tumors with enhanced expression of ICAM-1 by direct in vivo observations and may partially explain the salutary effect of increased ICAM-1 expression on adoptive immunotherapy. This suggests the possible application of adhesion molecule expression in the cellular therapy of cancer.

Animals↗
PubMed1997

Admission prediction of expected final myocardial infarct size using weighted ST-segment, Q wave, and T wave measurements.

Formulas for predicting final acute myocardial infarction (MI) size from ST-segment deviation on an initial electrocardiogram were proposed by Aldrich et al. for anterior and inferior infarct locations. This study of 529 patients who did not receive thrombolytic therapy was performed to determine the effectiveness of the Aldrich formulas for predicting final QRS MI size; to propose new formulas for predicting final MI size using ST-segment deviation, Q wave, and T wave information in a development population of 322 patients; and to evaluate the new formulas in a randomly selected population of 207 patients. The Aldrich formulas achieved correlations with final infarct size of r = .40 for anterior and r = .43 for inferior MI locations in the present population which are weaker than those previously reported. Formulas that consider electrocardiographic parameters in addition to ST-segment deviation were proposed for both anterior and inferior final MI size. In the test set of 207 patients, these models explained 16.9% and 15.2% of the variation in final MI size for anterior and inferior locations respectively. They may prove useful in assessing the extent of myocardial salvage where interventions are to be tested.

Electrocardiography↗
PubMed1997

Ultrasound-guided retrieval of small foreign objects in subcutaneous tissue.

STUDY OBJECTIVE: To identify the physical properties of the materials most easily located in subcutaneous tissue through the use of conventional ultrasound. METHODS: High-resolution real-time sonography was performed by a credentialed sonographer on a chicken breast impregnated with five objects-a metal paper clip, a wooden toothpick, a plastic coffee stirrer, a shard of glass, and an 18-gauge needle. Transducer frequencies ranging from 3.5 to 7.5 MHz with linear, curvilinear, and sector-scanning formats were used. All images were interpreted by a staff attending radiologist with other study authors present. The chicken breast was then subjected to radiography for comparison. RESULTS: Wood yielded the strongest acoustic shadow; plastic had the next-best acoustic shadowing. The 7.5-MHz probe yielded its best resolution at shallow depths, whereas the 5-MHz probe was best at greater depths. CONCLUSION: We conclude that ultrasonography is an excellent technique for the localization and retrieval of nonradiopaque foreign objects in the superficial subcutaneous tissue. It should be given consideration for use in the removal of nonradiopaque superficial foreign objects when conventional radiographic techniques are not effective.

Animals↗
PubMed1997

Acute renal failure due to indinavir crystalluria and nephrolithiasis: report of two cases.

Two patients with oliguric acute renal failure (ARF) attributed to crystalluria and nephrolithiasis with obstructive uropathy caused by the human immunodeficiency virus protease inhibitor indinavir are described. In both patients, ARF resolved with administration of intravenous fluids. One patient required urologic intervention to relieve bilateral ureteral obstruction.

Acute Kidney Injury↗
PubMed1997

Actinomycosis oto-mastoiditis.

Actinomycosis of the temporal bone is uncommon. There have only been 24 cases previously reported in the English literature. The responsible organism is Actinomyces israelii, an anaerobic filamentous Gram positive bacterium. While the cervico-facial region is the most common site of the disease, involvement of the temporal bone is rare. The diagnosis can sometimes be made clinically by identification of sulphur granules in a glue-like substrate but in all cases involving the temporal bone, the diagnosis has been made at histopathology. Effective therapy consists of surgery followed by the long-term administration of penicillin.

Actinomycosis↗
PubMed1997

v-Abl protein tyrosine kinase (PTK) mediated suppression of apoptosis is associated with the up-regulation of Bcl-XL.

We demonstrated previously that the activation of v-Abl protein tyrosine kinase (PTK) in IC.DP murine pre-mast cells resulted in suppression of apoptosis after withdrawal of interleukin 3 (IL-3), that protein kinase C (PKC) translocated to the nucleus 6 h after v-Abl PTK activation and that inhibition of PKC restored apoptosis after IL-3 deprivation in the presence of v-Abl PTK activity. Here we demonstrate that v-Abl PTK activation is followed by an approximately twofold increase in mRNA level of Bcl-XL by 6 h and a corresponding increase in Bcl-XL protein level by 24 h. Bcl-xL RNA and protein decreased in IL-3 deprived cells in the absence of v-Abl PTK activity. Exposure of cells with v-Abl PTK active to the PKC inhbitor calphostin C (125 ng/ml) prevented the increase in Bcl-xL protein and resulted in apoptosis. No changes in Bax or Bcl-2 protein level were noted after IL-3 withdrawal and/or activation of v-Abl PTK. Bak was barely detectable and Bad protein level decreased in cells undergoing apoptosis. The data suggest that suppression of apoptosis by v-Abl PTK in the absence of IL-3 is associated with PKC signalling and the upregulation of Bcl-xL in IC.DP cells.

Animals↗
PubMed1997

Design of the cyclops flap for chest-wall reconstruction.

The cyclops flap is a little-known but not forgotten alternative in chest-wall reconstruction for women. Female patients having a large, pendulous breast with a contralateral adjacent defect may be reconstructed by this technique. The flap derives its name from the repositioning of the remaining nipple to the center of the chest. The design of the flap is described. By knowing the width and length of the defect, the surgeon can design incisions on the remaining breast tissue that will allow the flap to advance easily, reliably filling the defect. The flap is an axial-pattern flap nourished by the lateral thoracic artery and the variable external mammary artery. This arterial inflow will serve the medial portion of the flap. The operation is straightforward and predictable. In using this design scheme three times in the last two years, there have been no complications. There is little discomfort after surgery. Occasionally, patients will benefit from this reconstructive option.

Aged↗
PubMed1997

Reduced naphthylphthalamic acid binding in the tir3 mutant of Arabidopsis is associated with a reduction in polar auxin transport and diverse morphological defects.

Polar auxin transport plays a key role in the regulation of plant growth and development. To identify genes involved in this process, we have developed a genetic procedure to screen for mutants of Arabidopsis that are altered in their response to auxin transport inhibitors. We recovered a total of 16 independent mutants that defined seven genes, called TRANSPORT INHIBITOR RESPONSE (TIR) genes. Recessive mutations in one of these genes, TIR3, result in altered responses to transport inhibitors, a reduction in polar auxin transport, and a variety of morphological defects that can be ascribed to changes in indole-3-acetic acid distribution. Most dramatically, tir3 seedlings are strongly deficient in lateral root production, a process that is known to depend on polar auxin transport from the shoot into the root. In addition, tir3 plants display a reduction in apical dominance as well as decreased elongation of siliques, pedicels, roots, and the inflorescence. Biochemical studies indicate that tir3 plants have a reduced number of N-1-naphthylphthalamic (NPA) binding sites, suggesting that the TIR3 gene is required for expression, localization, or stabilization of the NPA binding protein (NBP). Alternatively, the TIR3 gene may encode the NBP. Because the tir3 mutants have a substantial defect in NPA binding, their phenotype provides genetic evidence for a role for the NBP in plant growth and development.

Arabidopsis↗
PubMed1997

Primary intestinal Hodgkin's disease complicating ileal Crohn's disease.

An unusual primary intestinal lymphoma that occurred as a complication of ileal Crohn's disease is presented. Immunohistochemistry confirmed the light microscopic diagnosis of Hodgkin's disease (nodular sclerosing), and characterized a distinct mucosal nodule as a large-cell anaplastic non-Hodgkin's lymphoma. This unusual lymphoma developed while the patient was being treated with immunosuppressant medication. The present report is a reminder to clinicians of the possibility of occult lymphoma in ileal Crohn's disease.

Adult↗
PubMed1997

High-resolution CT in the evaluation of clinically suspected Pneumocystis carinii pneumonia in AIDS patients with normal, equivocal, or nonspecific radiographic findings.

OBJECTIVE: We prospectively studied AIDS patients with a high clinical pretest probability of Pneumocystis carinii pneumonia (PCP) in whom chest radiographic findings were normal, equivocal, or nonspecific with high-resolution CT (HRCT) to determine the incidence of PCP in these patients, to assess the diagnostic accuracy of HRCT for the presence or absence of PCP, to evaluate the role of HRCT in patient management, and to determine the clinical outcome of all patients 1 month after evaluation. SUBJECTS AND METHODS: All patients were referred to the Division of Pulmonary and Critical Care Medicine for diagnosis of clinically suspected PCP. Thirty-three patients were prospectively evaluated with HRCT within 24 hr of diagnostic bronchoalveolar lavage; 18 other patients who underwent HRCT were managed according to the HRCT interpretation and followed up clinically. All HRCT scans were independently reviewed by three chest radiologists; patchy or nodular ground-glass attenuation was considered to indicate "possible PCP." RESULTS: The incidence of PCP was 12% (6/51). The sensitivity of HRCT was 100%; specificity, 89%; and accuracy, 90% (p < .005). We had five false-positive and no false-negative interpretations. Some form of "airways disease" (n = 23) was the single most common HRCT interpretation. CONCLUSION: HRCT may allow exclusion of PCP in patients with findings that are normal, equivocal, or nonspecific on chest radiographs. Empiric therapy or immediate bronchoscopy can be avoided in many patients on the basis of the HRCT findings.

AIDS-Related Opportunistic Infections↗
PubMed1997

Assessment of health risks due to hazardous air pollutant emissions from electric utilities.

Hazardous air pollutant (HAP) emissions from electric utilities were evaluated. Cancer risks, as well as noncancer effects, due to inhalation exposure were assessed for 67 HAPs. Also, cancer risks due to multipathway exposure to radionuclide emissions were assessed. In addition, an assessment of the fate of mercury (Hg) through various environmental media was included. Results suggest arsenic, chromium, and nickel are the HAPs that present the highest cancer risk due to inhalation exposure. For noncancer effects due to inhalation exposure, hydrogen chloride appears to present the greatest potential concern. The risks due to multipathway exposure to radionuclides are estimated to be of similar magnitude to the risks posed by inhalation of arsenic and nickel. Mercury is of potential concern for multipathway exposures because it persists in the environmental and bioaccumulates in the aquatic food web. The study suggests there is a plausible link between Hg emissions from utilities and the Hg found in soil, water, and freshwater fish.

Air Pollutants↗
PubMed1997

Relationship between binocular disparity and motion parallax in surface detection.

The ability to detect surfaces was studied in a multiple-cue condition in which binocular disparity and motion parallax could specify independent depth configurations. On trials on which binocular disparity and motion parallax were presented together, either binocular disparity or motion parallax could indicate a surface in one of two intervals; in the other interval, both sources indicated a volume of random points. Surface detection when the two sources of information were present and compatible was not better than detection in baseline conditions, in which only one source of information was present. When binocular disparity and motion specified incompatible depths, observers' ability to detect a surface was severely impaired if motion indicated a surface but binocular disparity did not. Performance was not as severely degraded when binocular disparity indicated a surface and motion did not. This dominance of binocular disparity persisted in the presence of foreknowledge about which source of information would be relevant.

Humans↗
PubMed1997

Outcome prediction of the anterior open bite. Comparison of computer and clinician analysis of cephalograms.

Anterior open bite (AOB) may be expected to close spontaneously in approximately 50% of Caucasian patients. Computer-derived discriminant analysis of a single cephalometric radiograph has been shown to predict closure or non-closure in 88% of patients at the pre-puberal stage, in 74% at the puberal stage, and in 94% at the post-puberal stage. In this study, the predictive capacity of the computer analysis was tested against predictions made by groups of clinicians in Belfast and Toronto. The computer analysis was carried out on the first cephalometric radiographs of a new sample of 34 open bite cases collected serially and recorded over a minimum of 2 years. Thus, the spontaneous outcome was known to the authors. The first radiographs were shown to 20 clinicians in Belfast and 22 in Toronto who were asked to predict the spontaneous outcome. The computerised discriminant analysis made correct predictions in 85% and the clinicians in 64% of the sample. There were no significant differences between the predictions of clinicians in Belfast and Toronto, but computer prediction was more accurate than all grades of clinician. The predictions of qualified orthodontists were generally more accurate than prequalified orthodontists which were more accurate than those of undergraduate dental students but the differences did not rise to the level of statistical significance. For patients at the puberal stage the predictive capacity of qualified orthodontists was less than orthodontists in training. Computer prediction of the spontaneous outcome in open bite improves clinical diagnosis.

Adolescent↗