Can the outcome of autoaugmentation omentocystoplasty be improved? Urodynamic, histological, and collagen content evaluation in sheep model.

AIM: To compare histological and urodynamic outcome of the classical detrusorotomy with and without the aid of intravesical balloon distension. We also describe a new technique with multiple detrusor incisions instead of detrusorotomy. METHODS: A total of 24 animals were included in the study. Three different techniques of autoaugmentation cystoplasty were applied to surgically reduced bladders of 14 sheep. Five sheep underwent surgical reduction of bladder capacity as control group and five sheep underwent sham operation. In Group DIB (detrusor incision with balloon), standard whole thickness incisions on bladder wall were performed and a silicon balloon was inflated intravesically postoperatively. Group DMB (detrusorotomy with balloon) and Group DM (detrusorotomy) underwent standard detrusorotomy. After measuring capacities and compliances, animals were sacrificed on 90th postoperative day. Bladders were histopathologically evaluated. Expression of vascular endothelial growth factor (VEGF), CD31, and microvessel density (MVD) was noted. Quantification of collagen subtypes was also performed. RESULTS: The mean capacity and compliance for Group DM and control were not significantly different and both were lower than other augmentation groups and sham. In Groups DMB and DM fibrosis was significantly increased. The VEGF expression was lower in Group DIB with respect to other augmentation groups whereas MVD was not significantly different. Measurement of total collagen and collagen subtypes revealed an increase in total collagen of groups DMB and DM when compared to other groups. Quantification of collagen subtypes demonstrated that types I and III were significantly increased in aforementioned groups. CONCLUSION: Autoaugmentation omentocystoplasty in sheep model does not result in a reliable increase in bladder capacity and compliance. Intravesical balloon inflation makes the achievement more pronounced and significantly increases the bladder capacity and compliance.

Effect of Mg2SO4 usage on spinal cord ischemia-reperfusion injury: electron microscopic and functional evaluation.

OBJECTIVES: To evaluate the effects of intravenous magnesium sulfate (Mg(2)SO(4)) administration on ischemia-reperfusion injury of the spinal cord. MATERIAL AND METHODS: Sixteen rabbits were randomly assigned to the control (group I, 8 rabbits) and the study group (group II, 8 rabbits). The abdominal aorta was clamped for a period of 30 min followed by a reperfusion period of 60 min. The animals in group II received 0.25 ml/kg/h Mg(2)SO(4) intravenous infusion (15% Mg(2)SO(4)) throughout this procedure. The animals were then observed for 24 h after which their neurological states were evaluated and tissue samples obtained from the spinal cord were examined with electron microscopy. RESULTS: Aortic pressure distal to the cross-clamp during the occlusion period was 9 +/- 3 mm Hg in group I and 19 +/- 6 mm Hg in group II. All animals in group I were paraplegic at the end of the study. In group II the neurological outcome of 1 animal was poor while the other 7 animals were neurologically in a good condition. Electron microscopic examinations of the spinal cord tissues of group I revealed severe injury but the ultrastructure was well preserved in group II. CONCLUSIONS: Intravenous Mg(2)SO(4) administration may have protective effects on the ischemia-reperfusion injury of the spinal cord. We propose that Mg(2)SO(4) may be an additional protective pharmacological agent in thoracal and thoracoabdominal aortic surgery.

Contractile response of different segments of the latissimus dorsi muscle to chronic stimulation.

OBJECTIVE: This study was planned to investigate if there is any difference in terms of the muscle force between the distal and proximal segments of the latissimus dorsi muscle. SUBJECTS AND METHODS: An inplantable mock circulation system was placed around the latissimus dorsi muscle. The wrapping procedure around the implantable mock circulation was performed by using two different latissimus dorsi muscle segments. In group 1, the very proximal and in group 2, very distal part of the latissimus dorsi were wrapped. The main difference is the blood supply to the distal part of the latissimus dorsi that was interrupted during dissection. During the stimulation period which lasted 120 minutes, the pressure developed in this system and adenosine triphosphate (ATP) levels were measured. RESULTS: The stimulation at 20 Hz did not result in any change in pressure and metabolic data. When it was switched to 43 and 85 Hz, ATP levels decreased with a resultant drop in pressure in group 2. However ATP levels were 15.9 +/- 2.2 micromol/gr and 14.8 +/- 2.5 micromol/gr in group 1, 12.0 +/- 1.4 micromol/gr and 6.1 +/- 1.2 micromol/gr in group 2 at 43 and 85 Hz respectively (p < 0.05) at the end of the 90 minutes. The pressures at the same time interval were 89 +/- 11 and 102 +/- 7 mmHg in group 1, 61 +/- 7 and 65 +/- 8 mmHg in group 2 (p < 0.05). CONCLUSION: In this study, we demonstrated that changes in the distal segment of the latissimus dorsi muscle affects its performance in terms of metabolic and pressure changes during high frequency electrical stimulation at 43 and 85 Hz.

Magnesium-enriched coronary sinus retroperfusion during acute coronary artery occlusion.

BACKGROUND: The protective effect of coronary sinus retroperfusion in cases of ischaemic myocardium is clearly known. It restores the blood flow to the ischaemic tissue, reduces the infarct size, and improves the left ventricular pump function. METHODS: In this study, we investigated the effects of coronary sinus retroperfusion with the addition of magnesium sulphate on myocardial haemodynamics. A total of sixteen animals were entered into the study and divided equally into four groups: group I, control group, left anterior descending (LAD) coronary artery occlusion only; group II, LAD artery occlusion and Mg SO infusion; group III, LAD occlusion and retrograde coronary sinus perfusion; and group IV, LAD occlusion, retrograde coronary sinus perfusion and Mg SO infusion.(4) (4) RESULTS: Haemodynamic measurements were obtained throughout the study, at baseline, during the first and third hour of occlusion, and in the second, fourth and sixth hour of reperfusion. Although, the cardiac index was decreased in all groups, in the second hour of reperfusion it was significantly higher in groups III and IV compared to the control group. In the second hour of reperfusion cardiac index values were 56 +/- 5 and 63 +/- 6 ml/kg per min in groups III and IV respectively (P < 0.05) and as time passed this incremental change in groups III and IV became more apparent. In the fourth hour of reperfusion, group II showed significantly higher values than the control group. Group IV had higher values compared to group III at the fourth and sixth hours post-reperfusion. In general there were significant differences between groups II, III and IV at four and six hours post-reperfusion. The first derivative of pressure measured over time-the dP/dt value-was higher in groups III and IV compared to the control group in the first hour of occlusion (being 1650 +/- 55 and 1700 +/- 35 in groups III and IV respectively, and 1420 +/- 45 in the control group) and these differences continued throughout the occlusion and the reperfusion periods (P < 0.05). Group IV had the highest left ventricular stroke work index (LVSWI) values compared to the other groups in various pulmonary capillary wedge pressure (PCWP) measurements (P < 0.05). It was 0.78 g.m/kg at the 20 mmHg PCWP. CONCLUSIONS: Magnesium, if administered in an antegrade direction had only a limited effect, whereas magnesium-enriched retrograde coronary sinus perfusions appeared to significantly protect the ischaemic myocardium against the hazardous effects of ischaemic reperfusion injury.