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Biomedical subjects

J Duggan

Publications and source records attributed to J Duggan.

At least 19 recordsLinked to original sources

Motor block in regional anaesthesia. Quantification by muscle strength at the ankle joint.

A device based on a load cell was constructed to measure the strength of foot dorsiflexion and plantarflexion. Performance of the device was evaluated for both movements. The influence of foot position within the device, its use over a 30-min period at 30-s intervals and the effect of the removal and reapplication of the device on measured force of dorsiflexion and plantarflexion was studied in six volunteers. Both dorsiflexion and plantarflexion are suitable movements on which to base a device to quantify the density of motor block during the onset and offset of neuraxial block. Dorsiflexion has a number of advantages: muscle strength is independent of knee position, and therefore a below-knee device can be constructed; strength of dorsiflexion is less affected by the foot position; we found the device easier to apply using dorsiflexion as the heel tended to self-locate; innervation of the muscles responsible for dorsiflexion involves fewer spinal segments.

Adult↗

Colorectal cancer screening: potential pitfalls.

The National Health and Medical Research Council has recently issued guidelines on colo-rectal cancer, and given significant support to Colorectal Cancer Screening. However, the evidence of cost-effectiveness is inconclusive according to the Cochrane Centre. I argue that it would be wise to undertake trials that are appropriately funded. Otherwise, there is a risk that much money will be spent that cannot subsequently be justified.

Adult↗

The efficacy of subsurface flow reed bed treatment in the removal of Campylobacter spp., faecal coliforms and Escherichia coli from poultry litter.

The use of poultry waste as a fertiliser on arable land is an accepted method of waste treatment. However, run-off from such practices may result in contamination of the watercourse by human pathogens. In this study the effectiveness of using constructed wetlands as an alternative treatment for poultry manure waste was evaluated. Enumeration of Campylobacter spp., Escherichia coli, total coliforms and total aerobes were carried out on influent and effluent samples from reed beds loaded with poultry waste. For both sequential loading and continuous loading there was a statistically significant mean log reduction of 3.56 and 4.25 for E. coli, 3.2 and 3.88 for coliforms, 3.85 and 4.2 for total aerobic counts and 3.13 and 2.96 for Campylobacter spp., respectively. This method, which has been previously recognised as cost-effective and environmentally acceptable, provides an efficient method for reducing numbers of these bacteria in poultry waste and therefore an effective alternative treatment for such waste or waters containing run off from land previously spread with poultry manure.

Animals↗

Tsl and LP-BM5: a comparison of two murine retrovirus models for HIV.

The ts1 murine leukemia virus produces an immunodeficiency state in mice that parallels human immunodeficiency virus (HIV) infection in humans. Other murine leukemia viruses, such as LP-BM5 used in the murine acquired immune deficiency virus (MAIDS) model, have been studied extensively as a small animal model for HIV research, but lack many key similarities to HIV. Mice infected with ts1, however, utilize CD4 target cells for infection, undergo neuronal loss and demyelination, and develop clinical immunodeficiency. These features make this retrovirus in many ways an ideal candidate for a small animal model for HIV research. In this review article, the early development, the molecular and clinical pathogenesis of both the ts1 mutant of the Moloney murine leukemia virus and LP-BM5 are examined. Based on an extensive evaluation of the literature on LP-BM5 and ts1, it is concluded that the ts1 virus may serve as a better animal model to human retrovirus infection.

Amino Acid Sequence↗

Use of complementary and alternative therapies in HIV-infected patients.

The use of complementary and alternative medicine (CAM) therapies is widespread in many chronic illnesses, including human immunodeficiency virus (HIV) infection. The objective of this study was to determine the impact of increasingly effective antiretroviral therapy on the use of CAM in an HIV-positive patient population. A written survey was given to 191 HIV-positive outpatients. Participation was voluntary and anonymous. One hundred twenty-eight patients (67%) used CAM at some time to control HIV and 76 (40%) of the patients were currently using CAM. The major forms of CAM used were exercise (43%), lifestyle changes (38%), dietary supplements (37%), counseling (27%), herbal medications (26%), megavitamins (24%), and prayer therapy (24%). One hundred forty-one patients (74%) used a protease inhibitor medication, 28 (15%) used a protease inhibitor sparing regime, and 22 (11%) had no current or prior antiretroviral use. Eighty-two (43%) patients indicated that their doctor knew they used CAM and 56 patients (29%) received their information about CAM from a doctor or other health care professional. Of 128 patients who used CAM, 90 (70%) felt CAM improved their quality of life. Income of $15,000 or more per year and discontinuation of medications by patients for any reason in the past were the best predicators of CAM use for patients in general and also those on protease inhibitor therapy. CD(4) count, educational status, year of HIV diagnosis, and martial status were not effective predictors of CAM use. Use of CAM remains widespread among patients with HIV infection even with the availability of effective, yet noncurative antiretroviral therapy and does not correlate with type of antiretroviral therapy used or clinical status.

Adult↗

Benefits of treating hypertension in the elderly: should age affect treatment decisions?

Do the benefits of treating hypertension extend equally to all age groups, particularly the very elderly? Several large controlled trials have been published in recent years that confirm the benefits of the treatment of hypertension in terms of morbidity and mortality. However, these trials included only relatively small numbers of patients aged > or = 80 years. Data regarding such patients have been extracted and subjected to meta-analysis, but with inconclusive results. Further difficulties arise as a result of the range of therapeutic agents employed. Therefore, uncertainty still surrounds the value of treating very elderly patients with hypertension. The J-curve hypothesis, i.e. that a blood pressure threshold exists below which there is an increase in the rate of cardiac events, has been a concern in treating elderly patients. Upon close examination, this appears to be spurious. The Hypertension in the Very Elderly Trial study sets out to provide conclusive evidence for the benefits or otherwise of treating hypertension in the very elderly and has just commenced. The results of this trial will not be available for some time. In the meantime, should physicians initiate or continue treatment for very elderly individuals with hypertension? If so, what regimens should be employed and should target blood pressure levels be set? At the present time, it would appear sensible to provide treatment for very elderly patients with hypertension, particularly those with evidence of complications or target organ damage. In relatively healthy individuals with mild-to-moderate hypertension, the guiding principle should be 'the lower the blood pressure the better'. Regarding the choice of therapeutic agent, a low-dose diuretic remains the first choice therapy.

Age Factors↗

Connective tissue growth factor: potential role in glomerulosclerosis and tubulointerstitial fibrosis.

Transforming growth factor beta (TGF-beta) is a pivotal driver of glomerulosclerosis and tubulointerstitial fibrosis in renal diseases. Because TGF-beta also plays important anti-inflammatory and antiproliferative roles in mammalian systems, there has been a recent drive to elucidate downstream mediators of TGF-beta's pro-fibrotic effects with the ultimate goal of developing new anti-fibrotic strategies for treatment of chronic diseases. Connective tissue growth factor (CTGF) belongs to the CCN family of immediate early response genes. Several lines of evidence suggest that CTGF is an important pro-fibrotic molecule in renal disease and that CTGF contributes to TGF-beta bioactivity in this setting. CTGF expression is increased in the glomeruli and tubulointerstium in a variety of renal disease in association with scarring and sclerosis of renal parenchyma. In model systems in vitro, mesangial cell CTGF expression is induced by high extracellular glucose, cyclic mechanical strain and TGF-beta. Recombinant human CTGF augments the production of fibronectin and type IV collagen by mesangial cells and the effects of high glucose on mesangial cell CTGF expression and matrix production are attenuated, in part, by anti-TGF-beta antibody. In aggregate, these observations identify CTGF as an attractive therapeutic target in fibrotic renal diseases.

Connective Tissue Growth Factor↗

Vaccine era measles in an adult.

Measles should be included in the differential diagnosis of patients with fever and the characteristic viral exanthem, even if a history of adequate immunization is obtained. We present the case of a 23-year-old white female who developed high fever (103 degrees F), brightly erythematous eruptions on the face, sore throat, dry cough, and myalgia 5 days after her return to the United States following a trip to Calcutta, India. The patient had extensive facial erythema from the hairline to the neck, but some areas beneath the chin were spared. Fine erythematous papules extended down the anterior neck, and white papules were seen on the buccal mucosa. The erythematous macules spread to the trunk and extremities, eventually becoming confluent and desquamating over a period of 1 week. Defervescence occurred with desquamation. Measles serology revealed the IgM antibody as positive and the IgG antibody as negative despite 2 measles, mumps, and rubella (MMR) vaccinations at ages 15 months and 7 years. Skin biopsy was consistent with viral infection.

Adult↗

Systolic Hypertension in Europe (Syst-Eur) trial phase 2: objectives, protocol, and initial progress. Systolic Hypertension in Europe Investigators.

The Systolic Hypertension in Europe (Syst-Eur) trial proved that blood pressure (BP) lowering therapy starting with nitrendipine reduces the risk of cardiovascular complications in older (> or = 60 years) patients with isolated systolic hypertension (systolic BP > or = 160 mm Hg and diastolic BP < 95 mm Hg). After the completion of the Syst-Eur trial on 14 February 1997, 3506 consenting patients (93.0% of those eligible) were enrolled in phase 2 of the Syst-Eur trial. This open follow-up study aims to confirm the safety of long-term antihypertensive therapy based on a dihydropyridine. To lower the sitting systolic BP below 150 mm Hg (target BP), the first-line agent nitrendipine (10-40 mg/day) may be associated with enalapril (5-20 mg/day), hydrochlorothiazide (12.5-25 mg/day), both add-on study drugs, or if required any other antihypertensive agent. On 1 November 1998, 3248 patients were still being followed, 86 patients had proceeded to non-supervised follow-up, and 43 had died. The median follow-up in Syst-Eur 2 was 14.3 months. At the last available visit, systolic/diastolic BP in the patients formerly randomised to placebo (n = 1682) or active treatment (n = 1824), had decreased by 13.2/5.2 mm Hg and by 4.6/1.6 mm Hg, respectively, so that the between-group BP difference was 1.7 mm Hg systolic (95% Ci: 0.8 to 2.6 mm Hg; P < 0.001) and 0.9 mm Hg diastolic (95% Cl: 0.4 to 1.5 mm mm Hg; P < 0.001). At the beginning of Syst-Eur 2, the goal BP was reached by 25.4% and 50.6% of the former placebo and active-treatment groups; at the last visit these proportions were 55.9% and 63.1%, respectively. At that moment, 45.9% of the patients were on monotherapy with nitrendipine, 29.3% took nitrendipine in combination with other study drugs. Until the end of 2001, BP control of the Syst-Eur 2 patients will be further improved. Cardiovascular complications and adverse events, such as cancer or gastro-intestinal bleeding, will be monitored and validated by blinded experts.

Aged↗

Renal-dose (low-dose) dopamine for the treatment of sepsis-related and other forms of acute renal failure: ineffective and probably dangerous.

1. Low-dose ('renal-dose') dopamine (i.e. 1-3 micrograms/kg per min) is used widely for the treatment of acute renal failure induced by ischaemia, toxins and/or sepsis. Here we review the scientific rationale, experimental studies and clinical trials evaluating its use in these settings. 2. Renal-dose dopamine augments renal blood flow, sodium excretion and probably glomerular filtration rate in healthy humans and experimental animals and limits ATP utilization and oxygen requirements in nephron segments at risk of ischaemic injury. Renal-dose dopamine is renoprotective in several ischaemic and nephrotoxic models of acute renal failure. 3. However, most studies in humans have not demonstrated prevention of acute renal failure in high-risk patients or improved outcome in those with established acute renal failure. While the safety profile of dopamine in these settings has not been extensively defined, it is known the drug may precipitate serious cardiovascular and metabolic complications in the critically ill. Therefore, we suggest that renal-dose dopamine should not be used for selective renal vasodilatory and natriuretic actions in those patients with acute renal failure until its efficacy is established in randomized control trials. 4. Renal-dose dopamine may be most valuable when combined with agents targeting other events in acute renal failure, such as cast formation, epithelial cell injury and tubule regeneration. These recommendations should not preclude the use of dopamine for its systemic effects in heart failure and septic shock.

Acute Kidney Injury↗

Molecular and pathologic characterization of an AIDS-related body cavity-based lymphoma, including ultrastructural demonstration of human herpesvirus-8: a case report.

Body cavity-based lymphoma, also known as primary effusion lymphoma, is a newly recognized acquired immunodeficiency syndrome (AIDS)-related lymphoma that has been linked to the Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8). To date, direct visualization of the virus in a clinical sample has not been demonstrated. We have performed an extensive clinical, histologic, immunophenotypic, ultrastructural, and molecular genetic correlative study on multiple tissue samples obtained premortem and at autopsy from an patient with AIDS with Kaposi's sarcoma and body cavity-based lymphomas. We demonstrate the presence of human herpesvirus-8 in a primary clinical sample at the ultrastructural and molecular level, as well as document multiple lymphomatous tumor masses at autopsy.

Adult↗

Response to dehydration in elderly patients in long-term care.

Elderly patients in long-term care have a high plasma osmolality (pOSM) and associated increased mortality. In these patients, we examined pOSM, thirst (visual analogue scale, VAS) and arginine vasopressin (AVP) response to 16-hour dehydration and 2-hour rehydration. Twelve patients were randomly divided into two groups (A & B). Group A had their fluid balance monitored for two weeks, group B did not. Single measurements of VAS, pOSM and AVP were conducted on days 0, 7 and 13. Dehydration tests were conducted in both groups at the start of the study (DAY 1), and at the end of the two-week period (DAY 14). There were no significant differences between group A and B, so the results are presented for the two groups combined. There was a significant increase in both pOSM and VAS during dehydration, and a significant fall in both variables during rehydration [F (9,99) = 18.69, p < 0.001, and F(9,99) = 11.25, p < 0.001, respectively]. Plasma AVP did not change significantly during either dehydration or rehydration [F (9,99) = 0.59, p = 0.8]. There were no significant differences in response for any of the three variables between DAY 1 and DAY 14. We conclude that elderly patients in long-term care exhibit changes in thirst and osmolality during dehydration and rehydration, and that these responses are reproducible. The lack of a significant AVP response requires further investigation.

Aged↗

Treatment of hypertension in the elderly.

Hypertension is present in over 50% of elderly patients and constitutes a major risk factor for cardiovascular morbidity and mortality. This paper reviews the rationale for treating hypertension in the elderly, discusses the choice of antihypertensive therapy and optimal target blood pressure, and summarizes ongoing clinical trials. The major questions that remain to be answered are the optimal level of blood pressure reduction in the elderly and the long-term efficacy and safety of newer antihypertensive agents compared with diuretics and beta-blockers.

Aged↗

Clinical trial enrollers vs. nonenrollers: the Cardiac Arrhythmia Suppression Trial (CAST) Recruitment and Enrollment Assessment in Clinical Trials (REACT) project.

The Recruitment and Enrollment Assessment in Clinical Trials (REACT) was a National Heart, Lung, and Blood Institute (NHLBI)-sponsored substudy to the Cardiac Arrhythmia Suppression Trial (CAST). Two-hundred-sixty (260) patients who enrolled in CAST and 140 partially or fully eligible patients who did not enroll were compared across several parameters, including demographic variables, disease severity, psychosocial functioning, health beliefs, recruitment experience, and understanding of informed consent procedures used in CAST. Significant predictors of enrollment included several demographic variables (e.g., being male, not having medical insurance), episodes of ventricular tachycardia, and health beliefs (e.g., extra beats are harmful, a higher degree of general health concern). Enrollment was higher for those who read and understood the informed consent and those who were initially recruited after hospital discharge, particularly nondepressed patients. In the multivariate model, the key variables that emerged were the patient's reading of the informed consent form and the patient's lack of medical insurance. These results suggest that (1) the clinical trial staff's interaction with the patient and the time when recruitment is initiated contribute significantly to the decision to enroll; and (2) it may be a greater challenge to motivate patients to enroll in future clinical trials if health care reform improves access to medical insurance coverage. Some of the significant variables are modifiable, suggesting interventions that may increase enrollment rates in future trials.

Aged↗