Biomedical subjects

Michael J Taylor

Publications and source records attributed to Michael J Taylor.

21 records · Page 2Linked to original sources

PubMedDate not supplied

The role of preservation solution on acid-base regulation during machine perfusion of kidneys.

To meet the current clinical organ demand, efficient preservation methods and solutions are needed to increase the number of viable kidneys for transplantation. In the present study, the influence of perfusion solution buffering strength on renal pH dynamics and regulation mechanisms during kidney ex vivo preservation was determined. Porcine kidneys were hypothermically machine perfused for 72 h with either Unisol-UHK or Belzer-Machine Perfusion solution, Belzer-MP solution. Renal perfusate samples were periodically collected and biochemically analyzed. The UHK solution, a Hepes-based solution (35 mM), provided a more efficient control of renal pH that, in turn, resulted in minor changes in the perfusate pH relative to baseline, in response to tissue CO2 and HCO3- production. In the perfusate of Belzer-MP kidney group a wider range of pH values were recorded and a pronounced pH reduction was seen in response to significant rises in pCO2 and HCO3- concentrations. The Belzer-MP solution, containing phosphate (25 mM) as its main buffer, and only 10 mM Hepes, had a greater buffering requirement to attenuate larger pH changes.

Acid-Base Equilibrium↗

PubMedDate not supplied

In-home respite intervention reduces plasma epinephrine in stressed Alzheimer caregivers.

OBJECTIVE: Some excess morbidity and mortality in Alzheimer caregivers (CGs) may be related to chronic activation of the sympatho-adrenal-medullary (SAM) system. Authors tested the efficacy of an in-home respite intervention to reduce peripheral markers of SAM activation and psychological distress in spousal caregivers of patients with Alzheimer disease. METHODS: Caregivers were classified as Vulnerable (n = 27) or Non-Vulnerable (n = 28). Vulnerable CGs were those with a severe mismatch between caregiving demand and help received in the preceding 6 months. CGs had plasma catecholamine levels sampled at rest and in response to a stressor (speech task) before and 1 month after a 2-week in-home respite intervention. Self-reported symptoms of anxiety and depression were also obtained. RESULTS: ANOVA revealed a group x treatment interaction: At the 1-month follow-up, plasma epinephrine declined significantly in the vulnerable caregivers who received respite, but rose in those who were wait-listed. No effect was found for norepinephrine, heart rate, blood pressure, or psychological symptoms. CONCLUSION: Findings suggest that an in-home respite program may reduce SAM activation independent of psychological symptoms. To the extent that sympathetic activation mediates pathophysiological events, these results suggest an approach that may reduce morbidity and mortality in certain caregivers.

Aged↗

PubMedDate not supplied

In vitro evaluation of vascular endothelial and smooth muscle cell survival and apoptosis in response to hypothermia and freezing.

The success of endovascular techniques such as balloon angioplasty and stenting in the treatment of atherosclerotic vascular disease has been limited by an aggressive proliferative response leading to neointimal hyperplasia and re-stenosis. A new endovascular therapy combining cold treatment with balloon dilation has been proposed to prevent arterial re-stenosis. In order to evaluate the potential of this application, studies were conducted investigating the effects of hypothermia and freezing on human arteries at the cellular level. Cultured arterial endothelial cells and smooth muscle cells were chilled or frozen under controlled thermal conditions. The viability response of the cells was measured with a variety of assays quantifying necrosis, apoptosis, and cell proliferation. These data establish correlations between thermal conditions and the extent and nature of arterial freezing injury. Arterial smooth muscle cells were found to be susceptible to freeze-induced apoptosis in a temperature range of -5 to -15 degrees C. Endovascular cryotherapy designed to induce apoptosis in arterial smooth muscle cells may limit neointimal formation and thereby improve the durability of conventional angioplasty.

Apoptosis↗