15-Lipoxygenases and its metabolites 15(S)-HETE and 13(S)-HODE in the development of non-small cell lung cancer

BACKGROUND

15-S-Hydroxyeicosatetraenoic acid (15(S)-HETE) and 13-S-hydroxyoctadecadienoic acid (13(S)-HODE), both of which are metabolites of 15-lipoxygenases (15-LOXs), are endogenous ligands for peroxisome proliferator-activated receptor gamma (PPARgamma). The activation of PPARgamma inhibits cell growth and induces apoptosis in some cancers. The role of 15(S)-HETE) and 13(S)-HODE in the development of lung cancer is not clear.

METHODS

15-LOXs, 15(S)-HETE and 13(S)-HODE were monitored during the development of mouse lung tumours induced by the tobacco smoke carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and the levels of these markers were determined in 54 human non-small cell lung cancers.

RESULTS

15-LOXs, 15(S)-HETE and 13(S)-HODE levels were significantly reduced in human lung cancer tissue compared with non-tumour lung tissue (p=0.011 and p=0.022, respectively). In mouse experiments, 15(S)-HETE and 13(S)-HODE started to reduce at 26 and 30 weeks, respectively, after NNK treatment. The time frame of 15(S)-HETE reduction was in line with the decrease in 12/15-LOX mRNA and protein. A significant difference in the number of tumours in NNK-treated mice and controls was not observed until week 34 (p<0.05) and week 38 (p<0.01). The reduction in 12/15-LOX and 15(S)-HETE therefore predated the appearance of lung tumour. Furthermore, PPARgamma activity was decreased in NNK-treated mouse lungs compared with the control, and the decreased PPARgamma activity occurred at the same time points as the reduction in 12/15-LOX and 15(S)-HETE.

CONCLUSION

These findings indicate that the reduction in 15-LOX, 15(S)-HETE and 13(S)-HODE results in the decreased PPARgamma activity seen in lung tumours and contributes to the development of lung tumours induced by tobacco smoking.

Peri-operative blood transfusion increases length of hospital stay and number of postoperative complications in non-cardiac surgical patients

OBJECTIVES

To test the hypothesis that blood transfusion alone was a significant risk factor for in-hospital morbidity in non-cardiac patients.

DESIGN

Propensity analysis.

SETTING

University teaching hospital, Hong Kong.

PATIENTS

Consecutive non-cardiac patients seen in our department from 2006 to early 2009 who underwent a major procedure under general or spinal anaesthesia were included. Propensity analysis was performed to neutralise the confounding effects of preoperative variables and identify the true effects of transfusions on surgical outcomes.

MAIN OUTCOME MEASURES

Receipt of intra-operative and postoperative blood transfusion was established and the difference in proportions between patients who did and did not receive donor blood tested for mortality, overall morbidity, individual complications, and number of adverse events.

RESULTS

Transfused patients were significantly older and sicker, more likely to be male, to have lower haemoglobin values and undergo longer and more emergency surgical procedures than those not receiving a transfusion. Blood transfusion was predictive of length of postoperative hospital stay and number of complications before discharge. The amount of transfused blood was predictive of in-hospital mortality, with an odds ratio of 1.4 for each unit of blood received. The risk of a surgical wound infection was almost doubled when the patient had received a blood transfusion.

CONCLUSION

After controlling for the factors associated with an increased likelihood for receiving a blood transfusion, the actual transfusion was predictive of a slower and more eventful postoperative recovery with associated costs to both the patient and health services.

Robot-Assisted Excision of Ectopic Mediastinal Parathyroid Adenoma

Robot-assisted excision of an ectopic parathyroid adenoma in the superior mediastinum was performed in a 57-year-old man. The mass was located by methoxyisobutylisonitrile scan and computed tomography. Identification of the ectopic parathyroid adenoma was facilitated by the 3-dimensional images of the da Vinci robotic system, and resection was achieved using EndoWrist instruments. Robot-assisted excision of parathyroid adenoma located in the relatively inaccessible superior mediastinum proved to be feasible.

Video-assisted thoracic surgery excision of mediastinal hemangioma

A 62-year-old woman with a middle mediastinal hemangioma was successfully treated using a video-assisted thoracic surgery approach facilitated by segmental rib resection, despite an initial radiological study that showed encasement by the surrounding great vessels. Pathological examination confirmed a cavernous hemangioma. This approach offers potential resection in difficult cases of mediastinal tumor.

Roles of peroxisome proliferator-activated receptor-alpha and -gamma in the development of non-small cell lung cancer

Peroxisome proliferator-activated receptor (PPAR)-α and PPARγ participate in cell proliferation and apoptosis. Few studies have simultaneously investigated both PPARα and PPARγ in lung cancers in vivo. The roles of PPARα and -γ were investigated in the development of pulmonary tumors induced in the adult A/J mouse by treatment with 4-(methylnitrosamino)-l-(3-pyridyl)-lbutanone (NNK). Compared with the normal lung tissues, PPARγ expression was much higher in the NNK-induced lung tumor tissues. However, PPARγ transcriptional activity, and the levels of two major endogenous PPARγ ligands, 13-hydroxyoctadecadienoic acid and 15-hydroxyeicosatetraenoic acid, were significantly lower in the NNK-treated lung tissues. The ligand changes in mice were confirmed in human lung cancer tissues. Along with the alteration of PPARγ and its endogenous ligands, the level of PPARα and its activity were increased in the NNK-induced mouse lung tumors. Treatment of mice with the synthetic PPARγ ligand, pioglitazone, significantly inhibited the formation of mouse lung tumors induced by NNK. Our study demonstrated that the reduction of endogenous PPARγ ligands and increased PPARα occurred before the formation of lung tumors, indicating that the molecular changes play a role in lung carcinogenesis. The results suggest that the enhancement of PPARγ activity with its ligands, and the suppression of PPARα with its inhibitors, may prevent the formation of lung tumors, as well as accelerate the therapy of lung cancer. Our findings may also reveal the possibility of using the level of endogenous PPARγ ligands and the activities of PPARγ or PPARα as tumor markers for lung cancer.

Periannular extension of infective endocarditis

The periannular extension of infection is one of the most dangerous complications in patients with infective endocarditis (IE) and can significantly impact on the prognoses of these patients. The accurate detection and delineation of periannular complications are crucial in patient management, which may also provide guidance for surgical intervention. Echocardiography is the preferred imaging examination in both native and prosthetic valvular infections. However, it remains a great challenge for surgeons to successfully treat infections from panresistant organisms. Although staphylococci are reported to be the most common cause of aorto-cavitary fistulae, the association between this pathogen and clinical characteristics and patient outcome remains to be proven. Conversely, it has been observed that S. aureus is the most common cause of aorto-cavitary fistulae in patients with native valve endocarditis. The optimal management of patients with periannular extension of IE requires a multidisciplinary approach, with surgical input being an integral part of the treatment associated with the evolution of complex reconstructive techniques.

Multidisciplinary management of life-threatening massive hemoptysis: a 10-year experience

BACKGROUND

Life-threatening massive hemoptysis requires prompt action and thoracic surgical input. Although there are a number of reports regarding each therapeutic modality for medical or surgical treatment, the significance of a multidisciplinary strategy remains undetermined.

METHODS

From January 1995 to December 2005, 120 patients were referred to our cardiothoracic center with massive hemoptysis. We retrospectively reviewed and compared the outcomes of a recent 5-year period (2000 to 2005) with those from the previous 5 years (1995 to 1999), as we made major changes in our practice in 2000. We currently try to avoid surgery within 48 hours after onset of active hemoptysis and adopt bronchial artery embolization as a first-line therapy. Treatment decisions are made after discussions among intensive care unit physicians, thoracic surgeons, and interventional radiologists.

RESULTS

The former group had 49 patients (57.9 +/- 14.1 years old, 41 males), and the recent group, 71 (62.2 +/- 23.5 years old, 52 males). There were no significant differences for any characteristics studied between the groups. In analyses of short-term complications after surgery, the former had a higher in-hospital mortality rate than the recent group (15% versus 0%). Furthermore, postoperative complications were seen in 8 patients (30%) in the former, whereas those occurred in 3 patients (18%) in the recent group.

CONCLUSION

Bronchial artery embolization is an effective therapeutic tool and plays a pivotal role in management of life-threatening massive hemoptysis. Surgery is indicated when bronchial artery embolization is not suitable and can be safely performed in combination with a rigid bronchoscopy or bronchial artery embolization procedure. Our results indicate that a multidisciplinary approach should be adopted for management of life-threatening massive hemoptysis.

Effect of fetal anaemia on myocardial ischaemia-reperfusion injury and coronary vasoreactivity in adult sheep

AIMS

We investigated whether chronic fetal anaemia affects myocardial infarct in adulthood and elicits functional modifications in adult coronary vasoreactivity.

METHODS

Seven-month-old sheep that were made anaemic in utero and transfused to normal haematocrit before birth were studied. Infarct size was determined by tetrazolium after 1-h ischaemia (occlusion of the mid of left anterior descending artery) and 2-h reperfusion. The dose-response to vasoconstrictors and vasodilators was assessed in small resistance coronary arteries.

RESULTS

There were no significant differences between the animals previously subjected to in utero anaemia and the control animals regarding the percentage infarct size and the area-at-risk to the left ventricle. The ventricular function (dP/dt) was preserved. The percentage infarct size of the area-at-risk (70.7 +/- 3.5%) was larger than that in the controls (49.8 +/- 4.5%) (P = 0.006). The vascular responses were not altered. Endothelium-dependent relaxation to bradykinin (96.0 +/- 2.6% vs. 98.8 +/- 1.0%) was not affected by PGI(2) inhibitor (94.6 +/- 2.6% vs. 98.5 +/- 1.0%) but significantly reduced by the inhibition of nitric oxide (NO) in both anaemic (P < 0.05) and control (P < 0.001) groups with a significant right shift of EC(50) (P < 0.01). The non-NO-non-PGI(2)-mediated relaxation was slightly potentiated in anaemic animals.

CONCLUSIONS

Exposing fetal sheep to in utero anaemia in late gestation for 3 weeks may increase the susceptibility of adult hearts to ischaemia-reperfusion injury without major alterations in coronary vasomotor responsiveness. The impact of in utero anaemia at earlier period of pregnancy and on the earlier or later life of the adult is yet to be further investigated.

Dysfunction of pulmonary vascular endothelium in chronic obstructive pulmonary disease: basic considerations for future drug development

Chronic obstructive pulmonary disease (COPD) is one of the leading health problems worldwide and continues to be a major cause of morbidity and mortality in developed countries. The clinical features of COPD are chronic obstructive bronchiolitis and emphysema. Pulmonary vascular endothelial dysfunction is a characteristic pathological finding of COPD at different stages of the disease. Functional changes of pulmonary endothelial cells in COPD include antiplatelet abnormalities, anticoagulant disturbances, endothelial activation, atherogenesis, and compromised regulation of vascular tone which may adversely affect the ventilation-perfusion match in COPD. As the most important risk factor of COPD, cigarette smoking may initiate pulmonary vascular impairment through direct injury of endothelial cells or release of inflammatory mediators. Morphological changes such as denudation of endothelium and endothelial cell apoptosis have been observed in the pulmonary vasculature in COPD patients as well as functional alterations. Changes in the expression of tissue factor pathway inhibitor (TFPI), thrombomodulin, selectins, and adhesion molecules in pulmonary endothelial cells as well as complex regulation and interaction of vasoactive substances and growth factors released from endothelium may underlie the mechanisms of pulmonary endothelial dysfunction in COPD. The mechanism of endothelial repair/regeneration in COPD, although not fully understood, may involve upregulation of vascular endothelial growth factors in the early stages along with an increased number of bone marrow-derived progenitor cells. These factors should be taken into account when developing new strategies for the pharmacological therapy of patients with COPD.

An audit of risk factors for wound infection in patients undergoing coronary artery bypass grafting or valve replacement

OBJECTIVES

To investigate the epidemiology of surgical site infection in cardiac surgery patients operated on in 2006.

DESIGN

Retrospective study of a case-control sample.

SETTING

Cardiac surgery unit of a university teaching hospital in Hong Kong.

PATIENTS

Cardiac surgery patients with surgical site infection were matched by procedure type, sex, and year of surgery with non-infected patients.

MAIN OUTCOME MEASURES

Identification of risk factors for surgical site infection.

RESULTS

The infected and non-infected cardiac surgery patients did not differ in age, sex, or smoking history; however, patients with surgical site infection were significantly heavier (mean body mass index, 26.6 vs 23.9 kg/m2, P < 0.046). Almost 41% of the subjects had a history of diabetes mellitus, there being a significantly greater proportion among infected than non-infected patients (53.1% vs 28.1%, P < 0.042). All 37 of the patients without a diagnosis of diabetes had normal (ie < 8 mmol/L) preoperative glucose levels, but 99% of them yielded evidence of subsequent glycaemic dysfunction during or after surgery. Overall, 50% of the patients had a blood transfusion during the operation, with infected patients significantly more likely to have been transfused than the non-infected ones (65.6% vs 34.4%, P < 0.008).

CONCLUSIONS

There appears to be a relationship between surgical site infection in cardiac surgery patients and pre-existing (diagnosed and covert) diabetes mellitus and blood transfusion. Future studies should consider these factors in relation to surgical site infections, both in the wider surgical population and from a risk-minimisation perspective.

Haem oxygenase-1 plays a central role in NNK-mediated lung carcinogenesis

The tobacco-specific nitrosamine, 4-(N-methyl-N-nitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), is a potent lung cancer inducer. However, how NNK induces lung cancer is still largely unknown. Haem oxygenase (HO)-1 was evaluated in 30 pairs of lung cancer tumour samples and matched nontumour tissues from patients with a history of cigarette smoking. Expression of HO-1, p21(Cip1/Waf1/Cid1) (p21), B-cell lymphoma (Bcl)-2 family members, mitogen-activated protein kinase and nuclear factor (NF)-kappaB was also studied in lung cancer cells treated with NNK. The levels of HO-1 and p21 were significantly increased in lung tumour tissues. There was a positive relationship between these two proteins in the tumour. NNK stimulated lung cell proliferation and elevated the levels of HO-1, p21, inhibitor of apoptosis protein (c-IAP)2 and Bcl-2, but downregulated Bad. These effects of NNK were blocked by zinc protoporphyrin-XII, an HO-1 inhibitor. The NNK-mediated expression of HO-1 was governed by NF-kappaB and extracellular signal-regulated kinase 1/2, since blocking either of these prevented the stimulatory effect of NNK on HO-1, as well as molecules downstream of HO-1, such as p21, c-IAP2, Bcl-2 and Bad. In conclusion, haem oxygenase-1 plays a central role in NNK-mediated cell proliferation by promoting the expression of p21(Cip1/Waf1/Cid1), inhibitor of apoptosis protein 2 and B-cell lymphoma-2 but inhibiting the activity of Bad. Nuclear factor-kappaB and extracellular signal-regulated kinase 1/2 function upstream of haem oxygenase-1. Therefore, haem oxygenase-1 is likely to be a potential target in the treatment of smoking-related lung cancer.

Video-assisted thoracic surgery major lung resection can be safely taught to trainees

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) major lung resection for lung cancer has been an important part of thoracic surgical training program in our institution. In this study, we compared the results of VATS major lung resection performed by surgical trainees with those performed by experienced thoracic surgeons with specialist interest in VATS.

METHODS

From January 2002 to October 2006, the clinical data of 111 consecutive patients scheduled for VATS major lung resection were prospectively entered into the computerized clinical management system of the local health authority; these include patient demographics, comorbidity, operating time, postoperative complications, and outcome. We retrospectively compared the data of patients who were operated on by trainees with those who were operated on by experienced VATS surgeons.

RESULTS

One hundred and eleven patients with clinical stage I and II lung cancer underwent VATS major lung resection. Fifty-one (46%) of the procedures were performed by consultant surgeons and 60 VATS lung resections (54%) were performed by supervised trainees. Patients' demography and risk factors were comparable between the two groups. Trainees spent more time in performing the operation as compared with experienced VATS surgeons (mean operating time 162 minutes, p = 0.01). There was no significant difference in intraoperative or postoperative complications and outcomes between the two groups.

CONCLUSIONS

Video-assisted thoracic surgery major lung resection for early stage nonsmall-cell lung cancer can be taught to residents who work under the supervision of experienced VATS surgeons. Video-assisted thoracic surgery major lung resection for lung cancer should be an integral part of thoracic surgical training program.

Myocardial revascularization: surgery or stenting?

There is current debate regarding the relative merits and roles of surgical revascularization and percutaneous revascularization for patients with obstructive coronary artery disease. This article reviews the current literature relating to this subject.

Video-assisted thoracic surgery lobectomy for lung cancer is associated with less immunochemokine disturbances than thoracotomy

OBJECTIVE

Major surgery is immunosuppressive and could have an impact on postoperative tumor immunosurveillance and recurrence in cancer patients. Low circulating levels of insulin growth factor binding protein (IGFBP)-3 have been linked to advance prostate and the development of colonic cancers. This prospective study examined the early postoperative circulating levels of IGFBP-3, matrix metalloproteinase (MMP)-9, and tissue inhibitor of metalloproteinase (TIMP)-1 in early stage non-small cell lung cancer (NSCLC) patients undergoing major lung resection by VATS versus thoracotomy.

METHODS

Forty-two consecutive patients with resectable primary NSCLC were assigned to VATS or thoracotomy approach over a 7-month-period. Blood samples were collected preoperatively and postoperatively on days (POD) 1 and 3 for enzyme linked immunosorbent assay determination of IGFBP-3, MMP-9 and TIMP-1 levels in the serum.

RESULTS

There were no demographic differences between the two groups. VATS lung resection was associated with lower levels of MMP-9 and TIMP-1 on POD1 (median 628 vs 1311ng/ml, p=0.009; and 131 vs 211ng/ml, p=0.004, respectively) but higher levels of IGFBP-3 on POD3 (1366 vs 1144ng/ml, p=0.02), when compared with the thoracotomy approach. There was no perioperative mortality.

CONCLUSIONS

VATS major lung resection for NSCLC is associated with higher circulating levels of IGFBP-3, and lower levels of MMP-9 and TIMP-1, compared to the thoracotomy approach. The clinical relevance of these postoperative changes on tumor biology following lung resection for cancer warrants further investigation.

Video-assisted thoracic surgery for early stage lung cancer - can short-term immunological advantages improve long-term survival?

The development of video-assisted thoracic surgery (VATS) in the past decade has changed the way many pulmonary conditions are being treated. VATS has gained popularity among clinicians due to faster recovery following surgery, less postoperative pain and better cosmesis. It is well known that surgical trauma can induce a systemic inflammatory response and affect postoperative systemic immunity. Minimal access VATS has been shown to be associated with a reduced postoperative systemic inflammatory response. Recent evidence suggests VATS is also associated with better cellular immunity, and produces less immunochemokine disturbance following surgery, when compared with the thoracotomy approach. Circulating natural killer (NK) cell numbers and levels of insulin growth factor binding protein (IGFBP) are found to be higher, and plasma levels of matrix metalloproteinases are lower following VATS than that after thoracotomy. Maintenance of immune function with VATS may have important clinical implications in lung cancer surgery.