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Biomedical subjects

M E Mitchell

Publications and source records attributed to M E Mitchell.

146 records · Page 9Linked to original sources
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Human plasma causes rapid dysfunction in ex vivo pig hearts.

The use of hearts from large domestic animals represents a potential solution to the current human donor shortage. However, xenogeneic hyperacute graft rejection remains a major barrier to xenotransplantation. The purpose of this study was to use an ex vivo preparation to study variables that may correlate with hyperacute rejection in cardiac xenografts. Freshly excised hearts from 37 anesthetized pigs (10 to 37 kg) were perfused at 37 degrees C through the aorta with retrograde flow. The hearts functioned in a nonworking mode for 4 hours or until irreversible cardiac dysfunction occurred. Various perfusates were used: fresh whole autologous pig blood (n = 4), dog blood (n = 3), baboon blood (n = 5), human packed red blood cells (n = 2), human whole blood (n = 10), human whole blood and plasma (n = 3), and human plasma (n = 9), to which a modified Krebs-Henseleit bicarbonate buffer solution was added. Rapid loss of function was uniform and occurred most quickly (13 to 18 minutes) for hearts perfused with dog blood and human plasma. Isolated cardiac perfusion provided a means for the analysis of the cellular and plasma components of human blood to define which were required for rapid loss of function. The results indicated that the reaction was mediated by components present only in plasma.

Acute Disease↗
PubMedDate not supplied

[Posterior urethral valves: a change of concept].

OBJECTIVE: The basic question proposed in this article is whether early diagnosis and treatment of children with posterior urethral valves can prevent bladder and upper tract deterioration. If so, which is the best treatment? METHODS/RESULTS: Results with temporary urinary diversion for children with posterior urethral valves and renal insufficiency have not fulfilled expectations of an improved long-term outcome. Furthermore, there is mounting evidence that proximal urinary diversion with complete early bladder defunctionalization may result in reduced bladder capacity and compliance. In our experience early bladder cycling following valve ablation in the neonatal period is critical for the initiation of the healing process. Regardless of the initial appearance of the bladder and the status of the upper tract, early valve ablation may offer the best chance at functional recovery of normal bladder function, and restoration of upper tract function and anatomy without reconstructive surgery. In our series of 23 boys whose valves were resected at a mean of 21 days, bladder trabeculation resolved in 85% at one year. Follow up varied between 1 and 9 years. When compared to infants treated with urinary diversion, these children achieved superior potty training results. CONCLUSION: Bladder healing with early ablation seems to be dependent on bladder filling and emptying (cycling) with low outflow resistance. Ultimately, maximum recovery of renal function will depend on preventing the development of a hostile bladder. Early valve ablation may best achieve both goals of maximum bladder and renal functional recovery.

Humans↗