The investigation of corpus cavernosum smooth muscle dysfunction in low-flow priapism.

Prolonged low-flow (ischaemic) priapism results in a progressive alteration of the microenvironment within the corpus cavemosum with the development of hypoxia, acidosis and glucopenia and a reduction in the responsiveness to a-adrenergic receptor agonists. The aim of this study was to investigate the changes in the corporal microenvironment in patients presenting with refractory low-flow priapism and then develop an in vitro model to investigate the effects of hypoxia, acidosis or glucopenia on the tone of the rabbit corpus cavemosum. The recovery of smooth muscle contractility following exposure to these conditions was also investigated. Hypoxia, acidosis or glucopenia alone or in combination showed a sustained and significant reduction in the smooth muscle tone. This was most marked for conditions of hypoxia combined with glucopenia and the combination of hypoxia, acidosis and glucopenia. Reperfusion of tissue strips showed complete recovery of smooth muscle tone for all conditions except when hypoxia and glucopenia were combined or when hypoxia, glucopenia and acidosis were used in combination. Incomplete recovery of tone was not associated with an impairment of nitrergic relaxation responses but was associated with a significant reduction in tissue ATP concentrations and an increase in the number of TUNEL-positive nuclei. This indicates that in the presence of hypoxia, acidosis and glucopenia, failure of conventional a-adrenergic agonists in low-flow priapism is associated with irreversible smooth muscle cell dysfunction which is linked to ATP depletion and smooth muscle cell death

Monte Carlo simulation of Ising model on directed Barabasi-Albert network

The existence of spontaneous magnetization of Ising spins on directed Barabasi-Albert networks is investigated with seven neighbors, by using Monte Carlo simulations. In large systems we see the magnetization for different temperatures T to decay after a characteristic time tau, which is extrapolated to diverge at zero temperature.Comment: Error corrected, main conclusion unchanged; for Int. J. Mod. Phys. C 16, issue 4 (2005

Unilateral abducens nerve palsy: A presenting sign of sphenoid sinus mucocoeles

Sphenoid sinus mucocoeles can stimulate a variety of pathological conditions and patients can present to a range of specialists. Because of the relative rarity of sphenoid sinus mucocoeles, diagnosis is often delayed and these lesions can progressively expand and cause direct mechanical compression on adjacent structures. We present three cases which presented with an abducens nerve palsy. Early surgical intervention is advocated and these patients' symptoms resolved following surgery. Although several conditions can present with an abducens nerve palsy, it is important to consider a sphenoid sinus mucocoele in the differential diagnosis