Nathan Sheiner

Contemporary operative management of pulmonary metastases of colorectal origin.

The management of patients with metastatic disease from primary carcinoma of the colon and rectum is still controversial. To evaluate the results of resection of pulmonary metastases from patients with colorectal primaries, a retrospective study of all patients who underwent such resection was carried out at the teaching hospitals of McGill University and Université de Montréal. A total of 345 patients admitted with pulmonary metastases; 27 of them underwent pulmonary resection with the extent of the resection varying from wedge excision of the metastatic nodule to pneumonectomy. In 25 of the 27 patients the resection was considered curative. Eight of the 27 patients had resection of two metastatic lesions while the remaining 19 patients had resection of solitary lesions. The interval between resection of the primary colorectal malignancy and the resection of the metastatic lesion (disease-free interval) varied from 2 to 77 months with a median interval of 35 months. The five-year survival following resection of pulmonary metastases was 21 percent. A prolonged interval between treatment of the primary and resection of the pulmonary metastasis was associated with a longer survival. This retrospective study demonstrates that prolonged survival can be achieved following resection of pulmonary metastases from colorectal carcinoma.

BAK1 gene variation and abdominal aortic aneurysms

We sought to examine the role of genetics in the multifactorial disease, abdominal aortic aneurysm (AAA), by studying sequence variation in the BAK1 gene (BAK1) that codes for an apoptotic‐promoting protein, as chronic apoptosis activation has been linked to AAA development and progression. BAK1 abdominal aorta cDNA from AAA patients and nondiseased individuals were compared with each other, as well as to the BAK1 genomic sequence obtained from matching blood samples. We found specific BAK1 single nucleotide polymorphism (SNP) containing alleles in both aneurysmic (31 cases) and healthy aortic tissue (5 cases) without seeing them in the matching blood samples. These same BAK1 SNPs have been reported, although rarely (average frequency <0.06%), in reference BAK1 DNA sequences. Based on this and other similar observations, we propose a novel hypothesis postulating that multiple variants of genes may preexist in “minority” forms within specific nondiseased tissues and be selected for, when intra‐ and/or extracellular conditions change. Therefore, the fact that different BAK1 variants can exist in both diseased and nondiseased AA tissues compared to matching blood samples, together with the rare occurrence of these same SNPs in reference sequences, suggests that selection may be a significant factor in AAA ontogeny. Hum Mutat 30:1–5, 2009.

Atorvastatin Modulates Matrix Metalloproteinase Expression, Activity, and Signaling in Abdominal Aortic Aneurysms

Statins may reduce abdominal aortic aneurysm (AAA) progression. We sought to measure how atorvastatin (AT) treatment might modulate matrix metalloproteinase (MMP) expression and/or activity in human AAA. Tissue from human AAAs at surgical repair was obtained from patients who were either not on statins (NST, n = 19) or treated with AT (n = 19). Immunoblots measured expression and zymography measured activity. Expression of most proteins was greater in the central compared with distal AAA region. Matrix metalloproteinase 1, MMP2, MMP3, MMP9, Tissue Inhibitor of Metalloproteinase (TIMP2), TIMP3, TIMP4, or total Sma Mothers Against Decapentaplegia (SMAD2) expression did not differ with treatment. There was a trend toward reduced MMP8 and TIMP1 expression and MMP2 zymographic activity in the AT-treatment group. In contrast, AT-treated samples had significantly reduced MMP13 (P = .02), latent-transforming growth factor (TGF)-β (P = .02), and phospho-SMAD2 (P = .029) expression than NST-treated samples. We conclude that the AT-mediated decrease in MMP expression and activity reduces TGF-β signaling in the central region of human AAAs.

Successful repair of aortoesophageal fistula secondary to traumatic pseudoaneurysm

There have previously been only rare reported survivors of an aortoesophageal fistula resulting from a traumatic pseudoaneurysm. We report a case of a young man with a dramatic presentation who was successfully managed by immediate operative repair. A prosthetic graft was sewn within the sac of the aneurysm, with the aneurysm wall being used to protect the graft, and the esophagus was resected. Staged reconstruction of the esophagus was subsequently performed successfully. The patient is now alive and well 2 1/2 years later.

Treatment of Coronary Insufficiency by Counterpulsation: An Experimental Study

ounterpulsation is a mechanical method for supporting a failing circulation [1-4, 91. It can reduce the work of the left ventricle, C increase coronary blood flow [6,7], and experimentally has been shown to increase collateral circulation after acute coronary artery occlusion [5 ] . The last observation has been attributed to elevated diastolic perfusion pressure, which presumably overcomes peripheral resistance and opens up preexisting potential intramyocardial channels. The following report concerns experiments designed to study mechanically enhanced coronary circulation under conditions of chronic progressive insufficiency. Since critical coronary artery stenosis becomes manifest when combined narrowing of the two major branches of the left coronary artery exceeds 50% [8], survival of animals is dependent upon development of adequate intercoronary anastomoses.

Vein Harvesting by Long Blunt and Blind Dissection. A Standardized Technique in the Dog

A standardized method for harvesting veins from dogs is described. It involves skeletization of the vein and its collaterals by longitudinal blind and blunt dissection, thus separating the vein from its surroundings. This is followed by elevation and cutting of the subdermal tissue with an electrosurgical pencil. The method was found to be faster and less traumatic than the prevailing method which involves cutting the skin with a longitudinal incision and dissection of the vein in small increments.