Myocardial and Coronary Effects of Propofol in Rabbits with Compensated Cardiac Hypertrophy

Background: Myocardial effects of propofol have been previously investigated but most studies have been performed in healthy hearts. This study compared the cardiac effects of propofol on isolated normal and hypertrophic rabbits hearts.

Methods: The effects of propofol (10-1,000 [mu]m) on myocardial contractility, relaxation, coronary flow and oxygen consumption were investigated in hearts from rabbits with pressure overload-induced left ventricular hypertrophy (LVH group, n = 20) after aortic abdominal banding and from sham-operated control rabbits (SHAM group, n = 10), using an isolated and erythrocyte-perfused heart model. In addition, to assess the myocardial and coronary effects of propofol in more severe LVH, hearts with a degree of hypertrophy greater than 140% were selected (severe LVH group, n = 7).

Results: The cardiac hypertrophy model induced significant left ventricular hypertrophy (136 +/- 21%, P < 0.05). The pressure-volume relation showed normal systolic function but an altered diastolic compliance in hypertrophic hearts. Propofol only decreased myocardial contractility and relaxation at supratherapeutic concentrations (>= 300 [mu]m) in SHAM and LVH groups. The decrease in myocardial performances was not significantly different in SHAM and LVH groups. Propofol induced a significant increase in coronary blood flow which was not significantly different between groups. In severe LVH group, the degree of hypertrophy reached to 157 +/- 23%. Similarly, the effects of concentrations of propofol were not significantly different from the SHAM group.     

Minimum Alveolar Concentration of Volatile Anesthetics in Rats during Postnatal Maturation

Background: Although neonatal rats have become widely used as experimental laboratory animals, minimum alveolar concentration (MAC) values of volatile anesthetics in rats during postnatal maturation remain unknown.

Methods: We determined MAC values of volatile anesthetics in spontaneously breathing neonatal (2-, 9-, and 30-day-old) and adult Wistar rats exposed to increasing (in 0.1-0.2% steps) concentrations of halothane, isoflurane, or sevoflurane (n = 12-20 in each group), using the tail-clamp technique. MAC and its 95% confidence intervals were calculated using logistic regression and corrected for body temperature (37[degrees]C).

Results: In adult rats, inspired MAC values corrected at 37[degrees]C were as follows: halothane, 0.88% (confidence interval, 0.82-0.93%); isoflurane, 1.12% (1.07-1.18%); and sevoflurane, 1.97% (1.84-2.10%). In 30-day-old rats, the values were as follows: halothane, 1.14% (1.07-1.20%); isoflurane, 1.67% (1.58-1.76%); and sevoflurane, 2.95% (2.75-3.15%). In 9-day-old rats, inspired MAC values were as follows: halothane, 1.68% (1.58-1.78%); isoflurane, 2.34% (2.21-2.47%); and sevoflurane, 3.74% (3.64-3.86%). In 2-day-old rats, inspired MAC values were as follows: halothane, 1.54% (1.44-1.64%); isoflurane, 1.86% (1.72-2.01%); and sevoflurane, 3.28% (3.09-3.47%).     

Treatment of Nonmalignant Obstructive Iliocaval Lesions by Stent Placement: Mid-term Results

This report describes mid-term results of endovascular treatment of obstructive iliocaval lesions. Between November 1995 and December 1999, a total of 15 patients were treated by angioplasty and stent placement in the iliac vein. These patients were divided into two groups. Group I consisted of six patients with acute iliofemoral thrombosis of less than 10 days duration, with associated caval involvement in three cases. Angioplasty was performed after surgical thrombectomy, and creation of an arteriovenous fistula as a one-stage procedure in four cases and as a two-stage procedure in two cases. The underlying chronic lesion was stenosis of the left iliocaval junction (Cockett syndrome) in five cases and retroperitoneal fibrosis in one. Group II comprised nine patients with chronic symptomatic stenosis or occlusion. The etiology was Cockett syndrome in seven cases, post-thrombotic syndrome in three cases, including two associated with Cockett syndrome, and retroperitoneal fibrosis in one case. The mean number of stents per patient was 1.5. The mean duration of follow-up was 23.5 months. Evaluation of clinical outcome according to CEAP criteria for chronic syndromes showed significant improvement. Given good mid-term findings, venous angioplasty with stent placement appears to be a safe and effective technique for treatment of acute or chronic obstructive iliocaval lesions.     

Treatment of an early type II endoleak causing hemorrhage after endovascular aneurysm repair for ruptured abdominal aortic aneurysm

We report a case of ruptured abdominal aortic aneurysm emergently treated by endovascular aneurysm repair (EVAR) that developed a primary type II endoleak leading to persistent blood loss and retroperitoneal hematoma increase. Coil embolization resolved this. Although to our knowledge there are no recommendations regarding this, our report suggests that early type II endoleaks occurring after emergency EVAR for ruptured AAA should be treated when it is associated with blood extravasation outside the aneurysm sac.     

Morbidity, mortality, and long-term survival after sleeve lobectomy for non-small cell lung cancer.

OBJECTIVE: Sleeve lobectomy is a widely accepted procedure for central tumors for which the alternative is pneumonectomy. The purpose of this study is to assess operative mortality, morbidity, and long-term results of sleeve lobectomies performed for non-small cell lung carcinoma (NSCLC). METHODS: A retrospective review of 218 patients who underwent sleeve lobectomy for NSCLC between 1981 and 2005 was undertaken. There were 186 (85%) men and 32 women with a mean age of 61.9 years (range, 19-82 years). Eighty patients (36.6%) had a preoperative contraindication to pneumonectomy. Right upper lobectomy was the most common operation (45.4%). Vascular sleeve resection was performed in 28 patients (12.8%) and was commonly associated with left upper lobectomy (n=20; 9.1%; p=0.0001). The histologic type was predominantly squamous cell carcinoma (n=164; 75%), followed by adenocarcinoma (n=46; 21%). Resection was incomplete in nine (4.1%) patients. RESULTS: There were nine operative deaths; the operative mortality and the morbidity rates were 4.1% and 22.9%, respectively. A total of 14 (6.4%) patients presented with bronchial anastomotic complications: two were fatal postoperatively, seven patients required reoperation, three required a stent insertion, and two were managed conservatively. Multivariate analysis showed that compromised patients (p=0.001), current smoking (p=0.01), right sided resections (p=0.003), bilobectomy (p=0.03), squamous cell carcinoma (p=0.03), and presence of N1 or N2 disease (p=0.01) were risk factors for mortality and morbidity. Follow-up was complete in 208 patients (95.4%). Overall 5-year and 10-year survival rates were 53% and 28.6%, respectively. After complete resection, recurrence was local in 10 patients, mediastinal in 20, and distant in 25. By multivariate analysis, two factors significantly and independently influenced survival: nodal status (N0-N1 vs N2; p=0.01) and the stage of the lung cancer (stage I-II vs III, p=0.02). CONCLUSIONS: For patients with NSCLC, sleeve lobectomy achieves local tumor control, even in patients with preoperative contraindication to pneumonectomy and is associated with low mortality and bronchial anastomotic complication rates. Postoperative complications are higher in compromised patients, smokers, N disease, right sided resections, bilobectomies, and squamous cell cancers. The presence of N2 disease and stage III significantly worsen the prognosis.     

Ischemic preconditioning specifically restores complexes I and II activities of the mitochondrial respiratory chain in ischemic skeletal muscle

OBJECTIVE: Defective mitochondrial function has been reported in patients presenting with peripheral arterial disease, suggesting it might be an important underlying mechanism responsible for increased morbidity and mortality. We therefore determined the effects of prolonged ischemia on energetic skeletal muscle and investigated whether ischemic preconditioning might improve impaired electron transport chain and oxidative phosphorylation in ischemic skeletal muscle. METHODS: Thirty rats were divided in three groups: the control group (sham, n = 9) underwent 5 hours of general anesthesia without any ischemia, the ischemia-reperfusion (IR) group (n = 11) underwent 5 hours ischemia induced by a rubber band tourniquet applied on the left root of the hind limb, and in the third group, preconditioning (PC group, n = 10) was performed just before IR and consisted of three cycles of 10 minutes of ischemia, followed by 10 minutes reperfusion. Maximal oxidative capacities (V(max)) of the gastrocnemius muscle and complexes I, II, and IV of the mitochondrial respiratory chain were determined using glutamate-malate (V(max)), succinate (V(s)), and N, N, N,'N'-tetramethyl-p-phenylenediamine dihydrochloride ascorbate as substrates. RESULTS: Physiologic characteristics were similar in the three groups. Ischemia reduced V(max) by 43% (4.5 +/- 0.4 vs 7.9 +/- 0.5 micromol O(2)/(min x g dry weight), P < .01) and V(s) by 55% (2.9 +/- 0.3 vs 6.3 +/- 0.4 micromol O(2)/min/g dry weight; P < .01) in the IR and sham groups, respectively, and impairments of mitochondrial complexes I and II activities were evident. Of interest was that preconditioning prevented ischemia-induced mitochondrial dysfunction. Both V(max) and V(s) were significantly higher in the PC rats than in IR rats (+32% and +41%, respectively; P < .05), and were not different from sham values. CONCLUSIONS: Ischemic preconditioning counteracted ischemia-induced impairments of mitochondrial complexes I and II. These data support that ischemic preconditioning might be an interesting approach to reduce muscular injuries in the setting of ischemic vascular diseases.     

Thrombotic microangiopathy and anti-VEGF agents.

Sir, We report the occurrence of thrombotic microangiopathy (TMA)that may be directly related to vascular endothelial growthfactor (VEGF) Trap treatment, a fully humanized recombinantfusion protein containing extracellular portions of the extracellulardomains of two different VEGF receptors, VEGFR-1 and VEGFR-2.VEGF Trap is currently under evaluation in combination withLV5FU2-CPT11 in a     

The Wrightington approach to the radial head: biomechanical comparison with the posterolateral approach

PURPOSE: The Wrightington approach to the radial head involves elevating anconeus from the proximal ulna to expose the supinator crest and then osteotomizing the bony insertion of the lateral ligament complex to the ulna. This avoids incising through the substance of the lateral ligament complex. The purpose of this study was to determine if there is any difference in laxity changes between using the posterolateral versus the Wrightington approach in performing surgery upon the radial head in a cadaveric model. METHODS: Ten cadaveric elbows had a radial head fracture created and the medial collateral ligament divided. They then sequentially had the posterolateral or Wrightington approach to the radial head, fracture fixation, head excision, and replacement. After each step, valgus and varus laxity and ulnar rotation were determined with an electromagnetic tracking system. RESULTS: After each step, there was a greater increase in valgus and varus laxity in the posterolateral group compared with the Wrightington group. After surgical exposure, radial head fracture fixation, and radial head excision, there was a statistically significant difference in the changes in rotation between the posterolateral and Wrightington approaches, with the former resulting in an increase in external and the latter an increase in internal rotation. CONCLUSIONS: These results suggest that the newly described Wrightington approach is biomechanically superior to the posterolateral approach with regard to changes in elbow laxity after surgery to the radial head.