Dimitri Petsikas

Who should follow up lung cancer patients after operation

BACKGROUND It is unclear whether follow-up by a thoracic surgeon after lung cancer resection alters survival. METHODS The charts of 245 early stage (< or = IIB) non-small cell lung cancer patients, diagnosed between 1988 and 1995, were reviewed. Follow-up data were complete to January 1, 1997, in 96.3% (236 of 245) of cases. RESULTS Ninety of the 111 recurrences were detected before discharge from the thoracic clinic. Despite clinic follow-up, 66.7% (60 of 90) were identified by the family physician, and only 28.9% (26 of 90) by the surgeon. The remaining 4.4% (4 of 90) were detected by other physicians. Ninety-six percent (25 of 26) surgeon-detected recurrences had suspicious clinical or chest radiographic findings, compared with 92% for family physician-detected recurrences (55 of 60; not significant). The cost per recurrence detected by surgeons was Can

Effect of Preoperative Obstructive Sleep Apnea on the Frequency of Atrial Fibrillation After Coronary Artery Bypass Grafting

4,367. A 75% cost savings could ensure if patients were followed up by their family physician. There was no 5-year survival benefit for patients whose recurrence was detected by the surgeon. CONCLUSIONS Long-term follow-up after limited-stage non-small cell lung cancer resection could possibly be performed by a family physician alone without compromising overall survival, and with significant cost savings.

Analysis of CYP2A Contributions to Metabolism of 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone in Human Peripheral Lung Microsomes

Patients with obstructive sleep apnea (OSA) have intermittent hypoxia leading to atrial remodeling and this has been associated with the development of atrial fibrillation (AF). Postoperative AF is a common complication of coronary artery bypass grafting (CABG). The aim of this prospective study was to determine whether the presence of OSA predicts the occurrence of post-CABG AF (PCAF). This was a prospective single-center study. Patients undergoing elective CABG were evaluated and categorized as confirmed, high-risk, or low-risk OSA according to a modified Berlin questionnaire. PCAF was evaluated by 24-hour cardiac monitoring strip or 12-lead electrocardiography during the postoperative period, and validated by an electrophysiologist. We included 277 patients. OSA prevalence was 47.7%, with body mass index (31.0 vs 26.9 kg/m(2), p ≤0.001), advanced age (63.7 vs 66.4 years, p = 0.031), hypertension (78.0% vs 64.8%, p = 0.015), and diabetes (45.5% vs 28.3%, p = 0.003) more prevalent in the OSA group. PCAF was found to occur in 37.2% of all patients and OSA was found to be a strong predictor of PCAF (45.5% vs 29.7%, p = 0.007). PCAF was also associated with continuous positive airway pressure use (12.6% vs 5.2%, p = 0.027). Increased length of stay was associated with PCAF (6.5 vs 5.3 days, p = 0.006), as was longer time from surgery to occurrence of PCAF (p = 0.001). In conclusion, OSA was found to be a strong predictor of PCAF, which in turn was found to be associated with increased length of stay.

Dacron stimulation of macrophage transforming growth factor-β release

The objectives of this study were to determine the contributions of CYP2A13 and CYP2A6 to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) metabolism in human peripheral lung microsomes and to determine the influence of the genetic polymorphism, CYP2A13 Arg257Cys, on NNK metabolism. 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), the keto-reduced metabolite of NNK, was the major metabolite produced, ranging from 0.28 to 0.9%/mg protein/min. Based on total bioactivation of NNK and NNAL by α-carbon hydroxylation, subjects could be classified as either high (17 subjects) or low (12 subjects) bioactivators [(5.26 ± 1.23) × 10-2 and (6.49 ± 5.90) × 10-3% total α-hydroxylation/mg protein/min, P < 0.05]. Similarly, for detoxification, subjects could be grouped into high (9 subjects) and low (20 subjects) categories [(2.03 ± 1.65) × 10-3 and (2.50 ± 3.04) × 10-4% total N-oxidation/mg protein/min, P < 0.05]. When examining data from all individuals, no significant correlations were found between levels of CYP2A mRNA, CYP2A enzyme activity, or CYP2A immunoinhibition and the degree of total NNK bioactivation or detoxification (P > 0.05). However, subgroups of individuals were identified for whom CYP2A13 mRNA correlated with total NNK and NNAL α-hydroxylation and NNAL-N-oxide formation (P < 0.05). The degree of NNAL formation and CYP2A13 mRNA was also correlated (P < 0.05). Subjects (n = 84) were genotyped for the CYP2A13 Arg257Cys polymorphism, and NNK metabolism for the one variant (Arg/Cys) was similar to that for other subjects. Although results do not support CYP2A13 or CYP2A6 as predominant contributors to NNK bioactivation and detoxification in peripheral lung of all individuals, CYP2A13 may be important in some.

Mediastinal thymolipoma : A rare occurrence with striated myoid cells

This study evaluated the effect of Dacron on the release of macrophage transforming growth factor-β (TGF-β), an endothelial cell growth inhibitor. Rabbit peritoneal macrophages were grown in minimum essential medium (MEM) with 10% fetal bovine serum (FBS) in the presence or absence of Dacron (0.5mm × 3mm particles). Media were collected three times each week for 7 weeks. For the TGF-β bioassay, mink lung epithelial cells (CCL64) were grown in MEM with 10% FBS. Test-conditioned media, 100 μl, were added (n = 4), and incubated 48h. 3H-Thymidine (3H-TdR) uptake was determined and compared with 3H-TdR uptake using known pure TGF-β standards. Media samples were additionally pre-incubated with a neutralizing anti-TGF-β1 antibody and the 3H-TdR uptake again quantitated. TGF-β activity in the conditioned media of macrophages exposed to Dacron exceeded the control media groups in all weeks, reaching significance (P < 0.05) in weeks 3, 4, 5, 6 and 7. Pre-incubation of media samples with the anti-TGF-β1 antibody inhibited this TGF-β activity in all weeks with statistical significance in weeks 1, 2, 3, 5 and 7. The inhibitory effects of Dacron on endothelialization may be explained by the Dacron-induced release of TGF-β from macrophages.

Species Differences in the Infectability of Vascular Grafts

We describe a 49-year-old man who presented to hospital with unstable angina and who underwent emergency coronary artery bypass grafting. During the surgical procedure, an incidental anterior mediastinal mass was discovered. Histological examination of this mediastinal mass revealed a thymolipoma containing numerous polygonal, striated myoid cells that were immunoreactive for desmin, muscle-specific actin and myoglobin. Electron microscopy demonstrated numerous Z band structures confirming myoid differentiation. Even though the appearance of myoid cells in thymolipoma may be alarming, this tumor should be recognized as a benign entity. Thymolipomas containing striated myoid cells should be differentiated from more ominous thymic neoplasms, including teratomas and thymic liposarcomas. To our knowledge, this is only the third reported case of thymolipoma containing striated myoid cells.

The histology of human right atrial tissue in patients with high-risk Obstructive Sleep Apnea and underlying cardiovascular disease: A pilot study

The susceptibility of different species to bacteremia may influence the results of studies on vascular graft infection. The present study compares prosthetic graft infection in canine and porcine models. Thirty-four mongrel dogs and 38 Yorkshire pigs underwent replacement of the infrarenal aorta with a 3-cm segment of a woven Dacron prosthesis. At the time of closure, each animal received an intravenous inoculum of 10(2) to 10(8) Staphylococcus aureus (S. aureus). Graft cultures at 1 week produced a predictable infection rate in dogs, while pigs developed only random infections (dogs: 23/34; pigs: 7/38; p = .0001). The median infective dose (ID50) in dogs was 10(2.9) but pigs did not develop enough infections to determine this value. Electron microscopy revealed a smooth fibrin surface in grafts explanted from pigs, while grafts from dogs demonstrated bacteria enmeshed in an irregular fibrinous lining. Prosthetic vascular grafts in dogs are more susceptible to hematogenous infection than those in pigs. Because hematogenous infection in humans is a rare event, the swine model may be a more appropriate representation of the clinical situation.

Atypical localization of a left atrial myxoma at the free edge of mitral valve

Background Obstructive Sleep Apnea (OSA) results in intermittent hypoxia leading to atrial remodeling, which, among other things, facilitates development of atrial fibrillation. While much data exists on the macrostructural changes in cardiac physiology induced by OSA, there is a lack of studies looking for histologic changes in human atrial tissue induced by OSA which might lead to the observed macrostructural changes. Methods A case control study was performed. Patients undergoing coronary artery bypass grafting (CABG) were evaluated for OSA and categorized as high-risk or low-risk. The right atrial tissue samples were obtained during CABG and both microscopic histological analysis and Sirius Red staining were performed. Results 18 patients undergoing CABG were included; 10 high-risk OSA and 8 low-risk OSA in evenly matched populations. No statistically significant difference between the two groups was observed in amount of myocytolysis (p = 0.181), nuclear hypertrophy (p = 0.671), myocardial inflammation (p = n/a), amyloid deposition (p = n/a), or presence of thrombi (p = n/a), as measured through routine H&E staining. As well, no statistically significant difference in interstitial and epicardial collagen was observed, as measured by Sirius Red staining (for total tissue: p = 0.619: for myocardium: p = 0.776). Conclusions In this pilot study there were no observable histological differences in human right atrial tissue from individuals at high- and low-risk for OSA. Further investigation would be required for more definitive results.

Biotransformation of aflatoxin B1 in human lung

Myxomas represent more than 50% of benign cardiac neoplasm and are the most frequent cardiac tumors (1). Recent studies showed these neoplasms are commonly located in the left atrium (>90%), usually as a pedicled mass arising from the inter-atrial septum at the border of the fossa ovalis (2). Intra-cardiac masses should be differentiated as they could potentially represent a primary or secondary metastatic mass or endocarditis vegetations. We present a case of an exceedingly rare myxoma location, arising from the free-edge of the posterior mitral valve (MV) leaflet, which was incidentally identified in a 20-year-old female investigated for recent onset shortness of breath.