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Biomedical subjects

P J Dunne

Publications and source records attributed to P J Dunne.

8 recordsLinked to original sources
PubMed2000

Type 1 IFN maintains the survival of anergic CD4+ T cells.

Anergic T cells have immunoregulatory activity and can survive for extended periods in vivo. It is unclear how anergic T cells escape from deletion, because both anergy and apoptosis can occur after TCR ligation. Stimulation of human CD4+ T cell clones reactive to influenza hemagglutinin peptides can occur in the absence of APCs when MHC class II-expressing, activated T cells present peptide to each other. This T:T peptide presentation can induce CD95-mediated apoptosis, while the cells that do not die are anergic. We found that the death after peptide or anti-CD3 treatment of a panel of CD4+ T cell clones is blocked by IFN-beta secreted by fibroblasts and also by IFN-alpha. This increases cell recovery after stimulation, which is not due to T cell proliferation. This mechanism for apoptosis inhibition rapidly stops protein kinase C-delta translocation from the cytoplasm to the nucleus, which is an early event in the death process. A central observation was that CD4+ T cells that are rescued from apoptosis after T:T presentation of peptide by IFN-alphabeta remain profoundly anergic to rechallenge with Ag-pulsed APCs. However, anergized cells retain the ability to respond to IL-2, showing that they are nonresponsive but functional. The prevention of peptide-induced apoptosis in activated T cells by IFN-alphabeta is a novel mechanism that may enable the survival and maintenance of anergic T cell populations after TCR engagement. This has important implications for the persistence of anergic T cells with the potential for immunoregulatory function in vivo.

Antigen-Presenting Cells↗
PubMed2000

Testicular torsion: time is the enemy.

BACKGROUND: The acute scrotum is a diagnostic dilemma, and testicular torsion is of primary interest because of its fertility problems for the patient and medico-legal issues for the surgeon. The present study aimed to correlate operative findings of patients with suspected testicular torsion with certain clinical variables and investigations to see if diagnosis and outcome could be improved. METHODS: A total of 99 patients underwent scrotal exploration for suspected testicular torsion at the Royal Brisbane Hospital between 1990 and 1995. Colour Doppler ultrasound, white blood count and urine microscopy results were documented, along with the patient's age and duration of testicular pain. RESULTS: Fifty-six patients were found to have torsion, and the testicular loss rate was 23%. Patients who experienced testicular pain for longer than 12 h had a testicular loss rate of 67%. A negative urine microscopy was suggestive of testicular torsion, but was not diagnostic. The white blood count did not aid in the diagnosis. Colour Doppler ultrasound of the scrotum was used on nine occasions with three false negative results and a sensitivity of only 57%. CONCLUSIONS: Time is the enemy when managing the acute scrotum. No investigation substantially improves clinical diagnosis enough to warrant any delay in definitive surgical intervention.

Adolescent↗
PubMed2000

The demographics and economics of long-term oxygen therapy.

Home oxygen therapy represents a scientifically validated and universally accepted therapeutic regimen for the treatment of chronic hypoxemia secondary to COPD. The clinical benefits of home oxygen, including a decrease in morbidity and often a concomitant increase in the quality of life have been repeatedly confirmed through rigorous worldwide trials, studies, and investigations. However, since home oxygen is an expensive treatment modality, important questions continue to be raised about the overall cost-benefit of the intervention. Such scrutiny is expected to continue, especially in the United States, as the entire issue of health care cost-containment remains atop the domestic political agenda. Providers of home oxygen therapy have traditionally realized quite favorable reimbursement for home oxygen equipment, especially for those patient-customers covered under the Medicare program. However, recent Medicare reimbursement reductions of more than 30% have raised serious questions about the ability of home oxygen providers, especially those with annual revenues less than $1 million, to sustain their historical high level of support services to home oxygen patient-customers. Of particular concern is the economic hardship of supplying portable oxygen, especially for those patient-customers with unusually high ambulatory needs. The use of oxygen-conserving devices is viewed by some as one strategy to better control the costs of supplying portable oxygen, although there are those who still question whether or not oxygen-conserving devices can effectively forestall arterial oxygen desaturation across the entire spectrum of ambulation. Given the evidence now being reported that compliance in using home oxygen as prescribed may well be much lower than originally believed, the time is probably right to revisit the role played by home oxygen providers in determining continuing need through the performance of periodic reassessments. Such reassessments, if designed according to prescribed and validated protocols and conducted by home respiratory therapists under orders of the prescribing physician, would be a valuable tool to ensure continued medical need and identifying noncompliance. This would help ensure that those needing and using home oxygen would continue to receive the benefit. At the same time, patient-customers who, for one reason or another, stop using their oxygen equipment despite repeated encouragement, would have the equipment removed. The net result would be that reimbursement dollars currently wasted on home oxygen equipment that is not being used could be reallocated for those patient-customers willing and able to use the equipment as prescribed.

Demography↗
PubMed1994

Demographics and financial impact of home respiratory care.

Healthcare policymakers, governmental and private alike, are now faced with an enormous challenge. Demands for improved access to cost-effective and high quality healthcare are emanating from all segments of our society. Clearly, the traditional model of admitting patients to an acute care hospital as a first-line intervention is losing favor. Although there will always be a role for acute hospital care, utilization of this high-cost setting must be better managed if runaway healthcare costs are to be brought under control. The concept of moving patients along the healthcare continuum as their response to treatment reduces the acuteness of their condition is rapidly gaining support, especially with third-party payors. Accordingly, home healthcare providers, including those offering respiratory home care services, can expect to see an increase in the number of referrals they receive. HME/RT providers must actively promote the benefits they can offer in terms of high quality, cost-effective outcome. It is not unrealistic to suggest that the savings realized by reducing an acute hospital stay by 1 day can easily cover the costs of providing respiratory home care for 4 to 6 weeks. One can only hope that such compelling arguments, occurring at a time when healthcare reform and restructuring is a national priority, will translate to more equitable reimbursement guidelines for respiratory home care providers. The past practice of only reimbursing for equipment and supplies fails to take into account the vital role played by the home respiratory therapist. Home respiratory equipment and supplies, while an important component of managing chronic respiratory disease, are only effective if used safely, properly, and in compliance with the prescribing physician's intentions. The use of skilled and dedicated home respiratory therapists to train patients, monitor and assess outcomes, and communicate with the prescribing physician ensures optimum results. It is time for reimbursement policies to recognize this vital role played by home respiratory therapists.

Continuity of Patient Care↗