Membrane permeabilization of colistin toward pan-drug resistant Gram-negative isolates

Abstract Pan-drug resistant Gram-negative bacteria, being resistant to most available antibiotics, represent a huge threat to the medical community. Colistin is considered the last therapeutic option for patients in hospital settings. Thus, we were concerned in this study to demonstrate the membrane permeabilizing activity of colistin focusing on investigating its efficiency toward those pan-drug resistant isolates which represent a critical situation. We determined the killing dynamics of colistin against pan-drug resistant isolates. The permeability alteration was confirmed by different techniques as: leakage, electron microscopy and construction of an artificial membrane model; liposomes. Moreover, selectivity of colistin against microbial cells was also elucidated. Colistin was proved to be rapid bactericidal against pan-drug resistant isolates. It interacts with the outer bacterial membrane leading to deformation of its outline, pore formation, leakage of internal contents, cell lysis and finally death. Furthermore, variations in membrane composition of eukaryotic and microbial cells provide a key for colistin selectivity toward bacterial cells. Colistin selectively alters membrane permeability of pan-drug resistant isolates which leads to cell lysis. Colistin was proved to be an efficient last line treatment for pan-drug resistant infections which are hard to treat.

Laparoscopic repair of traumatic intraperitoneal bladder rupture

Intraperitoneal rupture of the bladder is an uncommon condition that is usually caused by pelvic fractures. This is a true surgical emergency managed conventionally by open laparotomy with single or double layer repair. We present a case of successful laparoscopic repair of an intraperitoneal bladder rupture secondary to blunt abdominal trauma and pelvic fracture in a 37 year-old man. The repair was done using single layer repair, with successful results

Role of histamine H2 receptors in cardiovascular function

The purpose of this study was to evaluate the role of histamine receptors [H[2]] in cardiovascular function in rats. The finding in the present study revealed that H[2] receptor blocker rantidine Hcl in a dose 20 mg/Kg reduces the heart rate both invivo and invitro, and abolishes the positive chronotropic action of beta - adrenergic stimulation, induced by isoproterenol infusion in isolated perfused hearts in Langendorff preparation. Moreover, it reduces the basal myocardial flow rate, with normal response to beta - adrenergic stimulation. On the other hand, the inotropic responses were unaffected. Therefore, the sympatho-inhibitory action of H[2]-blocker, suggesting a potential clinical use in conditions associated with enhanced sympathetic tone such as coronary vascular diseases and heart failure

Effect of vitamin C on responses of isolated hearts to B-adrenergic stimulation

The aim of this study was to investigate the possible protective action of vitamin C, in different doses against the oxidative damage induced by excessive beta-adrenergic stimulation by isoproterenol on the isolated perfused rat heart in a Langendroff preparation. The finding revealed that vitamin C in all doses used [100 mg, 200 mg and 500 mg] reduces the positive Chronotropic response of beta- adrenergic stimulation. Also, it improves the myocardial flow rate in response to isoproterenol infusion.On the other hand, the inotropic responsiveness to isoproterenol is only abolished [reduced peak developed tension] with the large dose of vitamin C 500 mg. Therefor, the benefits of vitamin C against the deletarious effects of excessive beta- adrenergic stimulation of the heart have been demonstrated, although the disadvantageous actions of the large doses of vitamin C should be safeguarded