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Biomedical subjects

C Campbell

Publications and source records attributed to C Campbell.

At least 91 records · Page 5Linked to original sources
PubMed1999

Beyond the biomedical and behavioural: towards an integrated approach to HIV prevention in the southern African mining industry.

While migrant labour is believed to play an important role in the dynamics of HIV-transmission in many of the countries of southern Africa, little has been written about the way in which HIV/AIDS has been dealt with in the industrial settings in which many migrant workers are employed. This paper takes the gold mining industry in the countries of the Southern African Development Community (SADC) as a case study. While many mines made substantial efforts to establish HIV-prevention programmes relatively early on in the epidemic, these appear to have had little impact. The paper analyses the response of key players in the mining industry, in the interests of highlighting the limitations of the way in which both managements and trade unions have responded to HIV. It will be argued that the energy that has been devoted either to biomedical or behavioural prevention programmes or to human rights issues has served to obscure the social and developmental dimensions of HIV-transmission. This argument is supported by means of a case study which seeks to highlight the complexity of the dynamics of disease transmission in this context, a complexity which is not reflected in individualistic responses. An account is given of a new intervention which seeks to develop a more integrated approach to HIV management in an industrial setting.

Adult↗
PubMed1999

Observations on the optical effects of a cataract.

PURPOSE: To describe and measure the optical effects seen by a person with a cataract and to use these observations to deduce physical changes in the crystalline lens caused by the cataract formation. SETTING: Humphrey Systems, Dublin, California, USA. METHODS: Caustic patterns created on the retina by a bright point source of white light as that source is viewed at various far-point distances ranging from the anterior focal point of the eye to +15.00 diopters were observed. The subtended retinal angle of a diffractive ring of light created by a small bright source of white light was observed and measured. RESULTS: Three optical effects were seen and measured: multiple-image formation at certain far-point positions; a diffractive light ring surrounding small bright sources; a radial needle of bright light surrounding a small bright-white source. With a point source of light positioned at the anterior focal point of the eye, the Y sutures of the lens could be visualized. With the point source at other distances, characteristic caustic patterns could be visualized, allowing assessment of the lens' optical character. The subtended retinal angle of the diffractive ring was measured so the periodic lens structure could be evaluated. CONCLUSIONS: The lens acted refractively as if it were divided into 3 elements with noncoincident optical axes. These 3 segments were associated with areas defined by the Y sutures, causing 3 images to be formed at certain distances. The caustic patterns indicate that each segment is slightly toroidal with axes at about 120 degrees apart combined with overcorrected spherical aberration. The period structure creating the diffractive ring had a period of 10 microns, approximately the width of a cortical lens cell, indicating that fluid between the cells likely creates a diffractive phase grating.

Cataract↗
PubMed1999

Efficacy of repeat intravenous dosing of ondansetron in controlling postoperative nausea and vomiting: a randomized, double-blind, placebo-controlled multicenter trial.

STUDY OBJECTIVES: To compare repeat intravenous (i.v.) dosing of ondansetron 4 mg with placebo for the treatment of postoperative nausea and vomiting (PONV) in patients for whom prophylactic, preoperative ondansetron 4 mg i.v. was inadequate DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Ten outpatient surgical centers in the United States. PATIENTS: 2,199 male and female ASA physical status I, II, and III patients > or = 12 years old scheduled to undergo outpatient surgical procedures and receive nitrous oxide-based general anesthesia. INTERVENTIONS: Ondansetron 4 mg i.v. was administered to all patients before induction of general anesthesia. Patients who experienced PONV or requested antiemetic therapy within 2 hours after discontinuation of inhaled anesthesia were randomized (1:1) to either a repeat i.v. ondansetron 4 mg dose or placebo. MEASUREMENTS AND MAIN RESULTS: Of the 2,199 patients prophylactically treated with ondansetron 4 mg before anesthesia induction, 1,771 (80.5%) did not experience PONV or request antiemetic therapy during the 2 hours following discontinuation of anesthesia. Of the 428 patients who experienced PONV or requested antiemetic therapy during the same period, and were randomized to additional treatment (214 randomized to ondansetron, 214 randomized to placebo), the incidence of complete response (no emesis, no rescue medication, no study withdrawal) was similar for both ondansetron-randomized and placebo-randomized groups for the 2-hour (34% and 43%, respectively, p = 0.074) and 24-hour (28% and 32%, respectively, p = 0.342) postrandomization study periods. Repeat ondansetron dosing was not more effective than placebo in controlling either postoperative emesis or the severity/duration of postoperative nausea. The administration of an additional dose of ondansetron 4 mg postoperatively did not result in an increased incidence of adverse effects. CONCLUSIONS: In patients for whom preoperative prophylaxis with ondansetron 4 mg i.v. is not successful, a repeat dose of ondansetron 4 mg i.v. in the postanesthesia care unit does not appear to offer additional control of PONV.

Adolescent↗
PubMed1999

Transforming growth factor beta (TGF-beta) and obliterative bronchiolitis following pulmonary transplantation.

BACKGROUND: Obliterative bronchiolitis (OB) characterised by small-airway fibrosis is a major cause of morbidity and mortality after lung transplantation. TGF-beta has been implicated in the pathogenesis of fibrosis. METHODS: We immunohistochemically examined 380 transbronchial biopsies (from 91 pulmonary transplants) using TGF-beta polyclonal antibodies. OB and interstitial fibrosis were diagnosed and graded in all biopsies. Other potential histologic and clinical risk factors for OB were analysed. RESULTS: Procedures were heart and lung (n = 32), bilateral sequential lung (n = 18), and single lung transplantation (n = 41). The incidence of OB in this group was 28.5%. In all patients with OB, TGF-beta was immunolocalized in the airways and lung parenchyma. TGF-beta expression was greater in OB patients (median score 8, range 5-12) in comparison to patients without OB (median score 4, range 1-13), p < .0001. Positive TGF-beta staining preceded the histologic confirmation of OB by 6 to 18 months. The development of OB was associated with two HLA mismatches at the A locus (p = .02); recurrent acute rejection episodes (p < .0005); lymphocytic bronchiolitis (p = .0001); and tissue eosinophilia, regardless of the rejection grade (p < .0001). CONCLUSIONS: Increased expression of TGF-beta is a risk factor for the development of OB. Other risk factors are recurrent acute rejection, lymphocytic bronchiolitis, tissue eosinophilia, and two mismatches at the HLA-A locus. This suggests that the pathogenesis of progressive small airway fibrosis characteristic of OB may be inflammatory damage, followed by an aberrant repair process due to excessive TGF-beta production following allograft injury. Hence, modulation of TGF-beta levels or function by antagonists may represent an important approach to control OB.

Adult↗
PubMed1999

Assessing surgical patients' expectations and subsequent perceptions of pain in the context of exploring the effects of preparatory information: raising issues of gender and status.

The present study explored both patients' expectations and experiences of pain in the context of utilizing an established research procedure, which previously reported a significant effect of instructional information on post-surgical recovery. No research to date has systematically attempted to identify pre-operative expectations of post-operative pain, nor has it compared pre- and post-operative ratings. A further variable scrutinized during the study was patient gender.Thirty-two males and 31 females undergoing two types of elective surgery were randomly allocated into experimental and control conditions by a third party. Patients in the experimental group received additional instruction information pre-operatively from the anaesthetist and the control group received the routine pre-operative visit. Using a numerical pain scale, all participants provided ratings of expected pain levels and subsequently rated their pain following surgery.Results obtained were contrary to expectations with respect to the effects observed by the established study as instructional information had no significant effect on recovery variables. However, the study did suggest that pre- and post-operative pain ratings were broadly equivalent. A significant gender difference was also found with male patients expecting less pain than they perceived and an opposite pattern for females. Measuring both pain expectations and perceptions is considered a useful technique to inform pain management and is worthy of further investigation. The inconsistent effect of instructional information and the gendered rating patterns are considered in relation to gender and status differentials between health providers and have important implications for future research. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed1999

An optical device with variable astigmatic power.

A new variable power cross-cylinder lens set is described. It differs from the well known Stokes variable power cross-cylinder lens set, which is made of cylinder lenses of equal but opposite power, in that in the new variable power cross-cylinder lens set both lens elements are identical. These elements can be sphero cylindrical of any type and can be designed to give the same effect as a Stokes lens set or create a spherical bias or offset of a desired amount. The action of this lens set is analyzed using 3-dimensional refractive space.

Astigmatism↗
PubMed1999

The human DNA ligase III gene encodes nuclear and mitochondrial proteins.

We provide evidence that the human DNA ligase III gene encodes a mitochondrial form of this enzyme. First, the DNA ligase III cDNA contains an in-frame ATG located upstream from the putative translation initiation start site. The DNA sequence between these two ATG sites encodes an amphipathic helix similar to previously identified mitochondrial targeting peptides. Second, recombinant green fluorescent protein harboring this sequence at its amino terminus was efficiently targeted to the mitochondria of Cos-1 monkey kidney cells. In contrast, native green fluorescent protein distributed to the cytosol. Third, a series of hemagglutinin-DNA ligase III minigene constructs were introduced into Cos-1 cells, and immunocytochemistry was used to determine subcellular localization of the epitope-tagged DNA ligase III protein. These experiments revealed that inactivation of the upstream ATG resulted in nuclear accumulation of the DNA ligase III protein, whereas inactivation of the downstream ATG abolished nuclear localization and led to accumulation within the mitochondrial compartment. Fourth, mitochondrial protein extracts prepared from human cells overexpressing antisense DNA ligase III mRNA possessed substantially less DNA ligase activity than did mitochondrial extracts prepared from control cells. DNA end-joining activity was also substantially reduced in extracts prepared from antisense mRNA-expressing cells. From these results, we conclude that the human DNA ligase III gene encodes both nuclear and mitochondrial enzymes. DNA ligase plays a central role in DNA replication, recombination, and DNA repair. Thus, identification of a mitochondrial form of this enzyme provides a tool with which to dissect mammalian mitochondrial genome dynamics.

Amino Acid Sequence↗
PubMed1999

Fluid shear stress induction of the tissue factor promoter in vitro and in vivo is mediated by Egr-1.

Hemodynamic forces such as fluid shear stress have been shown to modulate the activity of an expanding family of genes involved in vessel wall homeostasis and the pathogenesis of vascular disease. We have investigated the effect of shear stress on tissue factor (TF) gene expression in human endothelial cells (ECs) and in a rat arterial model of occlusion. As measured by reverse transcriptase polymerase chain reaction, exposure of ECs to 1.5 N/m2 shear stress resulted in a time-dependent induction of endogenous TF transcripts of over 5-fold. Transient transfection of TF promoter mutants into cultured ECs suggests the involvement of the transcription factor Egr-1 in mediating the response of the TF promoter to shear stress. To address the importance of flow induction of Egr-1 in vivo, we have established a flow-restricted rat arterial model and determined the level of expressed Egr-1 and TF at the site of restricted flow using immunohistochemistry. We report an increase in the level of Egr-1 and TF protein in ECs expressed at the site of restricted flow. Elevated expression of Egr-1 and TF is restricted to a highly localized area, as evidenced by the fact that no significant increase in level can be detected at arterial sites distal to the site of occlusion. These findings suggest a direct role for Egr-1 in flow-mediated induction of TF and further substantiate the importance of shear stress as a modulator of vascular endothelial gene function in vivo.

Animals↗
PubMed1999

Communication skills in the operating department.

In the second of our Back to Basics series, Marion Taylor and Claire Campbell explore the subject of effective communication within the perioperative area. Communication is often cited as an essential element in the smooth running of any department, and this article gives food for thought for all, from novice to expert. As ever, if you have any comments, use your communication skills and get in touch with me via NATN headquarters.

Communication↗
PubMed1999

Patient care in the operating department (1).

Judging by the positive feedback I have received about this series it is a timely reminder--or introduction--to the perioperative area. It has been suggested that universities and colleges should be made aware of the existence of this series in order that students may benefit prior to the theatre placement. So why don't you recommend it to your tutors, universities and colleges? This article will introduce three aspects of patient care, undertaken in the operating department. These are prevention of errors in surgical procedures, patient positioning and pressure area care.

Humans↗
PubMed1999

Delivery of full dose CHOP chemotherapy to elderly patients with aggressive non-Hodgkin's lymphoma without G-CSF support.

Because of evidence that failure to deliver full dose CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) may compromise the outcome of elderly patients with aggressive non-Hodgkin's lymphoma (NHL), we attempted to deliver full dose CHOP to these patients. The objective of this review was to assess the relative received dose intensity (ARRDI), toxicity and outcome of elderly patients treated with curative intent with CHOP at our centre. Charts were reviewed of all patients > or = 65 years with newly diagnosed aggressive NHL referred to the Toronto-Sunnybrook Regional Cancer Centre (TSRCC) for initial management from 1990-1995 before routine use of G-CSF. Sixty eligible patients were identified. 31 received CHOP +/- radiation (XRT), 9 other curative treatment and 20, palliative treatment. The mean ARRDI calculated on 29/31 patients receiving CHOP was .86; 41%=1.0, 24%=.90-.99, 14%=.75-.89 and 21%=<.75. During 141 cycles of CHOP. 17 (12%) episodes of febrile neutropenia (FN) occurred in 14 (45%) patients and other grade 3/4 toxicity occurred in <10% of patients. There were 3 (10%) toxic deaths. Sixteen (52%) patients required a total of 29 admissions to hospital for FN (59%) or other causes. Of the 31 patients, 16 (52%) achieved a complete remission (CR), 7 (23%) a partial remission-1 (PR-1), 2 (6%) a partial remission-2 (PR-2), 1 (3%) had no response (NR), 2 (6%) had progressive disease and 3 (10%) were not evaluable (NE). The median progression free survival (PFS) and overall survival (OS) were (16+) months and (24.5) months respectively. We found that physician biases resulted in the selection of; younger patients (median 71 vs. 80 years), patients with a better ECOG performance status (> or =2, 13% vs. 50%) and patients with less co-morbid illness (42% vs. 90%) for attempt at curative treatment with CHOP chemotherapy. Age was never the sole reason for offering palliative treatment. In conclusion, a subset of patients over the age of 65 with aggressive NHL, who have a good performance status and minimal co-morbid illness can tolerate full dose CHOP chemotherapy without G-CSF support. Future strategies should emphasize full dose treatment with curative intent with minimization of both hematologic and non-hematologic toxicity. Clinical studies are required to determine whether routine G-CSF support will reduce toxicity or improve outcome in this group of patients.

Aged↗
PubMed1999

Automated identification of tubercle bacilli in sputum. A preliminary investigation.

OBJECTIVE: To use an automated method to detect tubercle bacilli in sputum specimens. STUDY DESIGN: Using fluorescence microscopy, tubercle bacilli were identified on auramine-stained sputum specimens. Images were then captured with a digital camera and enhanced through imaging processing techniques. The bacilli were recognized using neural network classifiers. RESULTS: This preliminary investigation demonstrated a sensitivity of 94.1% for the identification of individual bacilli. As there are usually fairly numerous tubercle bacilli in the sputum of patients with active pulmonary tuberculosis, the overall diagnostic accuracy of sputum smear-positive patients can be expected to be very high. CONCLUSION: Potential benefits of automated screening for TB bacilli are: rapid, accurate, inexpensive diagnosis; the ability to screen larger numbers of people; increased resources to monitor patients; and reduction in health risks to staff.

Evaluation Studies as Topic↗