Activating Immune Recognition in Pancreatic Ductal Adenocarcinoma via Autophagy Inhibition, MEK Blockade, and CD40 Agonism

BACKGROUND AND AIMS

Patients with pancreatic ductal adenocarcinoma (PDA) have not yet benefitted from the revolution in cancer immunotherapy due in large part to a dominantly immunosuppressive tumor microenvironment. MEK inhibition combined with autophagy inhibition leads to transient tumor responses in some patients with PDA. We examined the functional effects of combined MEK and autophagy inhibition on the PDA immune microenvironment and the synergy of combined inhibition of MEK and autophagy with CD40 agonism (aCD40) against PDA using immunocompetent model systems.

METHODS

We implanted immunologically "cold" murine PDA cells orthotopically in wide type C57BL/6J mice. We administered combinations of inhibitors of MEK1/2, inhibitors of autophagy, and aCD40 and measured anticancer efficacy and immune sequelae using mass cytometry and multiplexed immunofluorescence imaging analysis to characterize the tumor microenvironment. We also used human and mouse PDA cell lines and human macrophages in vitro to perform functional assays to elucidate the cellular effects induced by the treatments.

RESULTS

We find that coinhibition of MEK (using cobimetinib) and autophagy (using mefloquine), but not either treatment alone, activates the STING/type I interferon pathway in tumor cells that in turn activates paracrine tumor associated macrophages toward an immunogenic M1-like phenotype. This switch is further augmented by aCD40. Triple therapy (cobimetinib + mefloquine + aCD40) achieved cytotoxic T-cell activation in an immunologically "cold" mouse PDA model, leading to enhanced antitumor immunity.

CONCLUSIONS

MEK and autophagy coinhibition coupled with aCD40 invokes immune repolarization and is an attractive therapeutic approach for PDA immunotherapy development.

Pancreatic ductal adenocarcinoma progression is restrained by stromal matrix

Desmoplasia describes the deposition of extensive extracellular matrix and defines primary pancreatic ductal adenocarcinoma (PDA). The acellular component of this stroma has been implicated in PDA pathogenesis and is being targeted therapeutically in clinical trials. By analyzing the stromal content of PDA samples from numerous annotated PDA data sets and correlating stromal content with both anatomic site and clinical outcome, we found PDA metastases in the liver, the primary cause of mortality to have less stroma, have higher tumor cellularity than primary tumors. Experimentally manipulating stromal matrix with an anti-lysyl oxidase like-2 (anti-LOXL2) antibody in syngeneic orthotopic PDA mouse models significantly decreased matrix content, led to lower tissue stiffness, lower contrast retention on computed tomography, and accelerated tumor growth, resulting in diminished overall survival. These studies suggest an important protective role of stroma in PDA and urge caution in clinically deploying stromal depletion strategies.

Improved survival with VATS pleurectomy-decortication in advanced malignant mesothelioma

AIMS

Malignant mesothelioma is increasing in incidence and no current therapy significantly prolongs survival. Previous surgical strategies involved high-risk open procedures without achieving histologically clear resection margins. We present the results of VATS debulking pleurectomy-decortication in advanced disease.

METHODS

A consecutive series of patients with suspected malignant mesothelioma underwent thoracoscopic assessment to determine the feasibility of decortication, where this was not possible a biopsy alone was taken. Post-operative radiotherapy was administered to port sites, but no other adjuvant therapy was given. The two groups (biopsy only and pleurectomy-decortication) were composed of patients with histologically confirmed mesothelioma [28 and 51 patients, respectively]. The primary endpoint was comparison of actuarial patient survival. Secondary endpoints included post-operative air leak and duration of hospital stay.

RESULTS

The overall actuarial survival was 288 days and 67% of patients had died at the time of data analysis. The groups were matched for patient and tumour-related characteristics including age (66, 64 years, p=0.39) and tumour stage (median IMIG stage 3 [IQR 2-3] both groups, p=0.54). The biopsy only group had fewer air leaks (57, 84%, p=0.01) and a shorter hospital stay (4, 8 days, p=0.03). However, the pleurectomy-decortication group had favourable actuarial survival relative to the biopsy only group (416, 127 days, p<0.001). Multivariate analysis showed early stage (p<0.001), absence of pre-operative fever (p=0.03) and pleurectomy-decortication (p<0.001) as independent predictors of survival.

CONCLUSION

VATS pleurectomy-decortication is feasible in the majority of cases and independently improves survival for patients with advanced malignant mesothelioma.

The Pseudomonas aeruginosa quorum-sensing molecule N-3-(oxododecanoyl)-L-homoserine lactone inhibits T-cell differentiation and cytokine production by a mechanism involving an early step in T-cell activation

The Pseudomonas aeruginosa quorum-sensing molecule N-3-(oxododecanoyl)-L-homoserine lactone (OdDHL) has been reported to have immunomodulatory activity in several systems, although the mechanism of that activity remains to be fully characterized. We demonstrate here, using a defined in vitro model of antigen responses by T-cell receptor (TCR)-transgenic mouse splenic CD4 T cells, that the effect of OdDHL on activation and cytokine production is complete within 4 h of antigen or mitogen stimulation and does not depend on the insertion of OdDHL in the cell membrane, despite a previous report that immunosuppression by homoserine lactones required a minimum acyl chain length of 11 carbons (S. R. Chhabra, C. Harty, D. S. W. Hooi, M. Daykin, B. W. Bycroft, P. Williams, and D. Pritchard, J. Med. Chem. 46:97-104, 2003). We also demonstrate that while OdDHL can have toxic effects on nonlymphoid leukocytes, it does not induce significant cell death in T cells at the concentrations (< or =10 microM) used in these experiments. In addition, we show that primary and secondary antigen-specific cytokine responses are equally susceptible to inhibition by OdDHL and that the compound inhibits the differentiation of both Th1 and Th2 cells. However, the precise balance of cytokine production by CD4 T cells stimulated in the presence of OdDHL varies with both the antigen concentration and its affinity for the transgenic TCR. Thus, conflicting reports of the nature of the immunosuppression by OdDHL may be due in part to the differences in antigen affinity and concentration in different models.

Relationship between pulmonary function and lung cancer surgical outcome

The British Thoracic Society and American College of Chest Physician guidelines outline criteria for investigating patients for lung cancer surgery. However, the guidelines are based on relatively old studies. Therefore, the relationship between pulmonary function test results and surgical outcome were studied prospectively in a large cohort of lung cancer patients. From January 2001 to December 2003, 110 patients underwent surgery for lung cancer. All underwent full lung function testing in order to predict post-operative lung function. The hospital mortality rate was 3% and major complication rate 22%. There was poor overall outcome in 13%. Mean pre-operative lung function values were: forced expiratory volume in one second (FEV1) 2.0 L (79.4% of the predicted value), and carbon monoxide diffusing capacity of the lung (D(L,CO)) 73.6% pred. The mean post-operative lung function values were: FEV1 1.4 L (55.6% pred), and D(L,CO) 51.3% pred. All lung function values were better predictors of poor surgical outcome when expressed as a percentage of the predicted value. Using a threshold of pre-operative FEV1 of 47% pred resulted in the most useful positive and negative predictive probabilities, 0.90 and 0.67, respectively. Lung function values expressed as a percentage of the predicted value are more useful predictors of post-operative outcome than absolute values. The threshold of predicted forced expiratory volume in one second for surgical intervention could be lower (45-50% pred) than is currently accepted without increased mortality.

Effect of lung cancer surgery on quality of life

BACKGROUND

Health related quality of life (HRQOL) after surgery is important, although very limited data are available on the QOL after lung cancer surgery.

METHODS

The effect of surgery on HRQOL was assessed in a prospective study of 110 patients undergoing potentially curative lung cancer surgery at Papworth Hospital, 30% of whom had borderline lung function as judged by forced expiratory volume in 1 second. All patients completed the EORTC QLQ-C30 and LC13 lung cancer module before surgery and again at 1, 3 and 6 months postoperatively.

RESULTS

On average, patients had high levels of functioning and low levels of symptoms. Global QOL had deteriorated significantly 1 month after surgery (p = 0.001) but had returned to preoperative levels by 3 months (p = 0.93). Symptoms had worsened significantly at 1 month after surgery but had returned to baseline levels by 6 months. Low values on the preoperative HRQOL scales were not significantly associated with poor surgical outcome. However, patients with low preoperative HRQOL functioning scales and high preoperative symptom scores were more likely to have poor postoperative (6 months) QOL. The only lung function measurement to show a marginally statistically significant association with quality of life at 6 months after surgery was percentage predicted carbon monoxide transfer factor (Tlco).

CONCLUSION

Although surgery had short term negative effects on quality of life, by 6 months HRQOL had returned to preoperative values. Patients with low HRQOL functioning scales, high preoperative symptom scores, and preoperative percentage predicted Tlco may be associated with worse postoperative HRQOL.

Acute hydrothorax in CAPD. Eearly thoracoscopic (VATS) intervention allows return to peritoneal dialysis

BACKGROUND/AIMS

Hydrothorax is a complication of continuous ambulatory peritoneal dialysis (CAPD) occurring due to pleuroperitoneal fistulae. Several treatments exist with no consensus as to best management. We report on the largest series of video-assisted thoracoscopic surgery (VATS) treated pleuroperitoneal fistulae yet available.

METHODS

Between 1995 and 2000, we treated 6 CAPD patients for acute right hydrothoraces using VATS. Data pertaining to size and sterility of hydrothoraces, presence of diaphragmatic defects, surgical procedures performed, morbidity and return to CAPD were obtained.

RESULTS

Hydrothoraces were drained in all patients and there were no significant growths on subsequent culture. Fistulae were directly identified and closed in three patients. In the remaining patients, endoclips were placed across the base of small diaphragmatic blebs (the presumed site of communication). Parietal pleurectomy was performed uneventfully in all patients. There was no morbidity, all patients returned to haemodialysis and there have been no recurrences.

CONCLUSIONS

Pleuroperitoneal fistulae produce symptomatic hydrothoraces in CAPD patients. A variety of approaches to the problem have been described. This is the largest series of VATS available and shows the usefulness of this approach in both closing the defect and producing an effective pleurectomy to prevent recurrence.

Thoracoscopic thoracic duct ligation for traumatic chylothorax

Traumatic chylothorax requires surgical intervention when conservative medical management fails to reduce chyle leakage. This usually entails thoracotomy or laparotomy. We report a case in which successful ligation of a torn thoracic duct was achieved using a video-assisted thoracoscopic technique.

Effect of the blood substitute diaspirin crosslinked hemoglobin in rat mesenteric and human radial collateral arteries

The actions of the blood substitute diaspirin crosslinked hemoglobin (DCLHb) were investigated in rat (small mesenteric artery) and human (radial collateral artery) resistance vessels mounted in a wire myograph for isometric tension recording. DCLHb did not contract resting vessels from rats, but vasoconstrictor responses were observed in isolated arteries and perfused mesenteric beds prestimulated with threshold concentrations of methoxamine. The DCLHb contractile responses were greatly attenuated by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or endothelial removal, whereas BQ-123 (endothelin A receptor antagonist), prazosin (alpha1-adrenoceptor antagonist), or indomethacin (cyclooxygenase inhibitor) had no effect. Endothelium-dependent relaxations to carbachol in both rat mesenteric and human radial collateral artery were inhibited by DCLHb. Relaxations to carbachol were studied in the presence of L-NAME or 25 mM KCl to investigate the effect of DCLHb on endothelium-derived hyperpolarizing factor (EDHF) and nitric oxide, respectively. In both rat and human vessels, EDHF-mediated relaxations were not affected by DCLHb preincubation, whereas the nitric oxide component of carbachol-induced relaxations was practically abolished. In conclusion, inhibition of the effects of basal nitric oxide release underpins the vasoconstrictor effects of DCLHb. DCLHb effectively abolishes the nitric oxide component of carbachol-induced relaxation, with no effect on the EDHF-mediated component in both isolated rat mesenteric and human radial collateral arteries.

Tumor necrosis factor alpha increases human cerebral endothelial cell Gb3 and sensitivity to Shiga toxin

Hemolytic uremic syndrome (HUS) is associated with intestinal infection by enterohemorrhagic Escherichia coli strains that produce Shiga toxins. Globotriaosylceramide (Gb3) is the functional receptor for Shiga toxin, and tumor necrosis factor alpha (TNF-alpha) upregulates Gb3 in both human macrovascular umbilical vein endothelial cells and human microvascular brain endothelial cells. TNF-alpha treatment enhanced Shiga toxin binding and sensitivity to toxin. This upregulation was specific for Gb3 species containing normal fatty acids (NFA). Central nervous system (CNS) pathology in HUS could involve cytokine-stimulated elevation of endothelial NFA-Gb3 levels. Differential expression of Gb3 species may be a critical determinant of Shiga toxin toxicity and of CNS involvement in HUS.

The action of diaspirin cross-linked haemoglobin blood substitute on human arterial bypass conduits

BACKGROUND

Immediately available blood substitutes could transform medicine. In coronary artery surgery, vasoconstriction induced by some of these agents could have serious implications. We have examined some of the vasoactive effects of one of these blood substitute, diaspirin cross-linked haemoglobin (DCLHb), on isolated rings of human arterial conduits.

METHODS

Sections of human left internal mammary artery (LIMA) and radial artery (RA) were cut into 3-mm rings, mounted in individual organ baths containing aerated (95% O(2)/5% CO(2)) Krebs-Heinseleit solution at 37 degrees C and attached to isometric strain gauge for measurements of tension. All rings were tested for the presence of endothelium by addition of carbachol to rings pre-contracted with phenylephrine. The relative importance of nitric oxide (NO) in contraction mediated by the addition of DCLHb was studied.

RESULTS

Carbachol relaxed phenylephrine precontracted LIMA by 72.3+/-1.7% and RA by 97+/-0.7% confirming the presence of a functional endothelium. Sodium nitroprusside (SNP) caused complete relaxation of LIMA with an EC(50) value of 2.0+/-0.1x10(-8) M and RA with an EC(50) value of 1. 9+/-0.1x10(8) M. In the presence of DCLHb (10(-7) M), carbachol-induced relaxation was significantly reduced to 46.3+/-0. 7% (P<0.01) and the BC(50) value for SNP relaxation increased to 1. 2+/-0.1x10(-7) M (P<0.01). DCLHb caused rings to contract in the absence of phenylephrine with EC(50) values of 1.6+/-0.1x10(-7) M (LIMA) and 1.8+/-0.1x10(-7) M (RA). Presence of L-NAME (300 microM) caused no alteration in DCLHb-induced contraction.

CONCLUSION

In this study of isolated rings of human vessels, DCLHb causes a significant reduction in relaxation mediated by carbachol and SNP, which is likely to be due to its ability to bind NO. However, it is possible that other mechanisms might contribute to the vasoconstrictor effects of DCLHb and these might be amenable to anti-vasospastic strategies.

Lesson of the week. Unrecognised accidental overdose with diltiazem

Invasive haemodynamic monitoring should be considered when hypotension fails to respond to empirical treatments

Clinical versus actual outcome in cardiac surgery: a post-mortem study

BACKGROUND

Clinical attribution of the cause of death can be misleading, with the only true outcome measure being post-mortem analysis. Despite this there is very little published data on post-mortems following cardiac surgery.

METHODS

Prospective consecutive post-mortem data were collected on 167 patients (84.4% of all in-hospital cardiac surgical deaths) in a single institution. Clinical diagnoses were compared with post-mortem findings.

RESULTS

The mean age at death was 69.8 with 67.6% male. The proportion undergoing coronary artery bypass graft (CABG) alone was 52.1%, valve surgery 18.6%, valve+CABG 19.2% and other procedures 10.1%. The mean time to death was 7.9 days (range 0-87). The causes of death were cardiac 67.7%, gastrointestinal 9.6%, respiratory 8.4%, haemorrhage/technical failure 4.8%, stroke (cerebrovascular accident) 3.6%, multiorgan failure 3.0%, sepsis 1.8%, malignancy 0. 6% and trauma 0.6%. Post-mortem revealed an unsuspected cause of death in 19 (11.4%). These were gastrointestinal (infarction nine, perforation two), cardiac three, adult respiratory distress syndrome two, technical two and pulmonary embolus one. In addition, an unsuspected lung cancer was found in 1 patient who died of cardiac causes. When cardiac deaths were compared with non-cardiac causes the Parsonnet score was higher 20.0 (+/-1.4) vs. 15.3 (+/-1.6), P=0. 07; and a greater proportion tended to have poor ejection fractions (34 vs. 15%), P=0.12. There was no significant difference between the groups in terms of age, sex, operation, hypertension, diabetes, creatinine and body mass.

CONCLUSIONS

Post-mortem can determine unsuspected diagnoses in a significant proportion of cases. Pre-operative risk factors do not correlate with eventual cause of death. Post-mortem still has an important role to play in cardiac surgery.

Videothoracoscopic drainage of mediastinal abscess: an alternative to thoracotomy

A late-presenting high esophageal perforation that resulted in a massive mediastinal abscess and bronchopleural fistula in an elderly moribund patient unfit for radical surgery was successfully drained using a videothoracoscopic technique.

Inhibitory effects of glibenclamide on the contraction of human arterial conduits used in coronary artery bypass surgery

Glibenclamide has been shown to inhibit prostanoid-induced contraction in a number of blood vessel types. In this study, the effects of glibenclamide on the contraction of human peripheral arteries in response to both prostanoid and non-prostanoid agonists were compared and possible mechanisms of action were investigated. Segments of left internal mammary artery (LIMA) and radial artery, taken from patients undergoing coronary artery bypass graft (CABG) surgery, were mounted in organ baths containing physiological saline solution aerated with 95% O2/5% CO2 at 37 degrees C. Contractions were obtained by either the use of a thromboxane analogue (U46619), L-phenylephrine, KCl or CaCl2. The effects of glibenclamide on these contractions were observed and pEC50 values were determined after manipulation of a logistic curve-fitting equation. Concentration-dependent relaxation of U46619-contracted LIMA and radial artery was observed in the presence of glibenclamide, with calculated pEC50 values of 4.2+/-0.17 (n = 7) for LIMA and 3.26+/-0.48 (n = 5) for radial artery. Incubation of both LIMA and radial artery with glibenclamide (50 microM) caused the concentration-response curves for U46619 and L-phenylephrine to shift significantly to the right. Similarly the KCl tension relationship was caused to shift to the right. Finally, glibenclamide (100 microM) also had an inhibitory effect on Ca2+-induced tension in radial artery. These results show that the inhibitory effects of glibenclamide on human peripheral blood vessels are not restricted to prostanoid-induced contractions. Furthermore, evidence has been provided to suggest that these effects might be mediated through an interaction with voltage-sensitive Ca2+ channels.

Mesothelioma--VATS biopsy and lung mobilization improves diagnosis and palliation

OBJECTIVES

Mesothelioma is an increasingly frequent malignancy in which diagnosis is often delayed and disease diagnosed at an advanced stage. Earlier diagnosis and therapeutic intervention that can control recurrent pleural effusion may improve outlook and survival.

METHODS

A prospective series of 25 patients in whom mesothelioma was suspected was referred for histological diagnosis by video assisted-thoracoscopy (VAT) after failure of other methods. At the same operative procedure drainage of pleural effusion, cytoreductive pleurectomy and lung mobilization was performed where possible. Complete follow-up was obtained.

RESULTS

All patients had a histological diagnosis (100%) from the material sent for biopsy. In 23 patients this was mesothelioma, in two patients chronic empyema. All patients undergoing drainage of effusion, cytoreductive pleurectomy and lung mobilization subsequently were diagnosed of having mesothelioma stages III to IV. Fifteen out of 21 who underwent lung mobilization had closure of the pleural space. Post operative air leak in this group was a mean of 5 days (2-12 days). Recurrent effusion occurred in only one patient. Eleven patients remain alive at 1-2 years post operation with no hospital admissions for recurrent pleural effusion. In the six out of 21 who did not have closure of the pleural space, one remained alive 9 months post surgery. Five died within 1-6 months of the procedure. The average number of further hospital admissions for repeat drainage of effusion was 3 (1-6).

CONCLUSIONS

VATs provides adequate tissue for histological diagnosis where other methods fail. At the same operative sitting it provides a therapeutic intervention that allows drainage of effusion cytoreductive pleurectomy and lung mobilization in a significant number of cases. Where the pleural space can be closed this results in significantly fewer hospital admissions and appears to improve quality of life and length of survival. The price is a longer hospital stay due to prolonged air leak.

Current practice in thoracic sympathectomy

Thoracic sympathectomy has been performed for many years. With the recent development of video assisted thoracic surgical techniques the indications for surgery have increased, and the outcome is much better.

Increased levels of advanced glycation endproducts in the lenses and blood vessels of cigarette smokers

BACKGROUND

Advanced glycation endproducts (AGEs) arise from the spontaneous reaction of reducing sugars with the amino groups of macromolecules. AGEs accumulate in tissue as a consequence of diabetes and aging and have been causally implicated in the pathogenesis of several of the end-organ complications of diabetes and aging, including cataract, atherosclerosis, and renal insufficiency. It has been recently proposed that components in mainstream cigarette smoke can react with plasma and extracellular matrix proteins to form covalent adducts with many of the properties of AGEs. We wished to ascertain whether AGEs or immunochemically related molecules are present at higher levels in the tissues of smokers.

MATERIALS AND METHODS

Lens and coronary artery specimens from nondiabetic smokers and nondiabetic nonsmokers were examined by immunohistochemistry, immunoelectron microscopy, and ELISA employing several distinct anti-AGE antibodies. In addition, lenticular extracts were tested for AGE-associated fluorescence by fluorescence spectroscopy.

RESULTS

Immunoreactive AGEs were present at significantly higher levels in the lenses and lenticular extracts of nondiabetic smokers (p < 0.003). Anti-AGE immunogold staining was diffusely distributed throughout lens fiber cells. AGE-associated fluorescence was significantly increased in the lenticular extracts of nondiabetic smokers (p = 0.005). AGE-immunoreactivity was significantly elevated in coronary arteries from nondiabetic smokers compared with nondiabetic nonsmokers (p = 0.015).

CONCLUSIONS

AGEs or immunochemically related molecules are present at higher levels in the tissues of smokers than in nonsmokers, irrespective of diabetes. In view of previous reports implicating AGEs in a causal association with numerous pathologies, these findings have significant ramifications for understanding the etiopathology of diseases associated with smoking, the single greatest preventable cause of morbidity and mortality in the United States.

Comparison of p53 and DNA content abnormalities in adenocarcinoma of the oesophagus and gastric cardia

This study examined the association between 17p allelic loss, p53 gene mutation, p53 protein expression and DNA aneuploidy in a series of adenocarcinomas arising in the oesophagus and gastric cardia. 17p allelic loss was detected in 79% (15 of 19) of oesophageal and in 83% (29 of 35) of gastric adenocarcinomas. p53 mutations were detected in 70% (14 of 20) and 63% (26 of 41) of oesophageal and of gastric adenocarcinomas respectively. Both tumour types were associated with a predominance of base transitions at CpG dinucleotides. In five cases of oesophageal adenocarcinoma, the same mutation was detected both in tumour and in adjacent dysplastic Barrett's epithelium. Diffuse p53 protein expression was detected in 65% (13 of 20) and 59% (24 of 41) of oesophageal and of gastric tumours, respectively, and was associated with the presence of p53 missense mutation (Chi-squared, P < 0.0001). DNA aneuploidy was detected in 80% (16 of 20) of oesophageal and in 70% (28 of 40) of gastric tumours. No association was found between p53 or DNA content abnormalities and tumour stage or histological subtype. In conclusion, this study detected a similar pattern of p53 alterations in adenocarcinoma of the oesophagus and gastric cardia--molecular data consistent with the observation that these tumours demonstrate similar clinical and epidemiological features.

Barrett's oesophagus: microsatellite analysis provides evidence to support the proposed metaplasia-dysplasia-carcinoma sequence

The development of adenocarcinoma in Barrett's oesophagus is proposed to occur via a stepwise progression recognised histologically as a metaplasia-dysplasia-carcinoma sequence. In order to identify chromosomal loci involved in the malignant transformation of Barrett's epithelium and the development of oesophageal adenocarcinoma, microsatellite analysis was carried out on 17 cases of Barrett's-associated oesophageal adenocarcinoma. Samples of premalignant Barrett's epithelium adjacent to adenocarcinoma were obtained from seven of these cases. Allelic imbalance was detected in > 45% of informative cases of oesophageal adenocarcinoma on chromosome arms 3q (65%), 4q (71%), 5q (59%), 6q (59%), 9p (50%), 9q (47%), 12p (47%), 12q (65%), 17p (76%), and 18q (75%). Allelic imbalance at 4q, 17p, and 18q was significantly higher than the upper 95% confidence interval for background allelic imbalance. Allelic imbalance was detected at several loci in the premalignant epithelium from five of the seven cases studied. These loci included several chromosomal arms that had demonstrated high levels of allelic imbalance in oesophageal adenocarcinoma, namely, 4q (one case), 5q (two cases), 9 (three cases), 12q (five cases), 17p (four cases), and 18q (two cases). Novel microsatellite alleles were detected in both premalignant and malignant Barrett's epithelium. In three cases, dysplastic Barrett's epithelium and adjacent adenocarcinoma demonstrated the same pattern of novel microsatellite alleles at a number of loci. In conclusion, these data indicate chromosomal loci which may be specifically involved in the histological progression of Barrett's epithelium. The detection of shared novel microsatellite alleles in premalignant and malignant Barrett's epithelium is consistent with a process of clonal expansion underlying this progression.

Thrombin activates nuclear factor-kappaB and potentiates endothelial cell activation by TNF

Thrombin is the central bioregulatory enzyme in hemostasis and is generated in vascular beds in which inflammatory responses are ongoing. In this study, we examined the effect of thrombin, both alone and in combination with TNF, on gene expression in porcine aortic endothelial cells (EC). Thrombin (1-10 U/ml) induced increased mRNA levels of E-selectin, monocyte chemoattractant protein-1, IL-8, plasminogen activator inhibitor-1, and IkappaB-alpha. These effects were mimicked by a thrombin receptor-activating peptide; preincubation of thrombin with hirudin blocked the induction of mRNA, suggesting that the increased gene expression was due to thrombin-specific activity. Because these genes are known to contain nuclear-factor-kappaB (NF-kappaB)-binding elements in their promoter region, we next examined the ability of thrombin to activate this transcription factor. As detected by electrophoretic mobility shift assay, thrombin (10 U/ml) or thrombin receptor-activating peptide (100 microM) stimulated increased NF-kappaB-binding activity. Supershift analysis revealed that these complexes were comprised principally of the RelA (p65) and NF-kappaB1 (p50) Rel family members. Thrombin alone did not substantively increase protein levels of E-selectin despite the increase in E-selectin mRNA levels. However, thrombin (3-10 U/ml) stimulated a 10-fold enhancement in the ability of TNF (0.3-1.0 ng/ml) to induce E-selectin surface expression. Similar potentiation of TNF-induced NF-kappaB activity and E-selectin transcription by thrombin was observed in experiments utilizing luciferase reporter constructs expressed in bovine aortic EC. The ability of thrombin to potentiate TNF-induced EC activation thus provides an important mechanism by which products of the coagulation cascade may enhance cytokine-mediated inflammatory responses.

Thrombin activates nuclear factor-kappaB and potentiates endothelial cell activation by TNF

Thrombin is the central bioregulatory enzyme in hemostasis and is generated in vascular beds in which inflammatory responses are ongoing. In this study, we examined the effect of thrombin, both alone and in combination with TNF, on gene expression in porcine aortic endothelial cells (EC). Thrombin (1-10 U/ml) induced increased mRNA levels of E-selectin, monocyte chemoattractant protein-1, IL-8, plasminogen activator inhibitor-1, and IkappaB-alpha. These effects were mimicked by a thrombin receptor-activating peptide; preincubation of thrombin with hirudin blocked the induction of mRNA, suggesting that the increased gene expression was due to thrombin-specific activity. Because these genes are known to contain nuclear-factor-kappaB (NF-kappaB)-binding elements in their promoter region, we next examined the ability of thrombin to activate this transcription factor. As detected by electrophoretic mobility shift assay, thrombin (10 U/ml) or thrombin receptor-activating peptide (100 microM) stimulated increased NF-kappaB-binding activity. Supershift analysis revealed that these complexes were comprised principally of the RelA (p65) and NF-kappaB1 (p50) Rel family members. Thrombin alone did not substantively increase protein levels of E-selectin despite the increase in E-selectin mRNA levels. However, thrombin (3-10 U/ml) stimulated a 10-fold enhancement in the ability of TNF (0.3-1.0 ng/ml) to induce E-selectin surface expression. Similar potentiation of TNF-induced NF-kappaB activity and E-selectin transcription by thrombin was observed in experiments utilizing luciferase reporter constructs expressed in bovine aortic EC. The ability of thrombin to potentiate TNF-induced EC activation thus provides an important mechanism by which products of the coagulation cascade may enhance cytokine-mediated inflammatory responses.

Allelotype analysis of adenocarcinoma of the gastric cardia

To identify chromosomal loci involved in the development of proximal gastric adenocarcinoma, this study delineated the pattern of allelic imbalance in a series of 38 adenocarcinomas arising in the gastric cardia. A total of 137 microsatellite markers covering all autosomal arms, excluding acrocentric arms, were analysed. A mean of 35 out of a total of 39 chromosomal arms studied were informative for each patient. The tumour group demonstrated a high level of allelic imbalance, with an observed median fractional allelic imbalance of 0.47 for the 29 intestinal-type adenocarcinomas and 0.54 for the nine diffuse-type adenocarcinomas. Allelic imbalance was detected in >50% of informative cases in both histological subtypes on a number of chromosomal arms. In the intestinal subtype, these included, 3p (61%), 4q (71%), 5q (59%), 8p (60%), 9p (65%), 9q (83%), 12q (52%), 13q (52%), 17p (78%) and 18q (70%). A higher incidence of allelic imbalance was detected on chromosome 16q in tumours of the diffuse type relative to those of the intestinal type. A more detailed mapping on chromosomes 4q and 6q identified a number of cases with subchromosomal breakpoints. In conclusion, this analysis has indicated regions of the genome potentially involved in the development of proximal gastric carcinomas.

Expression and activation of protein kinase C isoforms in a human megakaryocytic cell line

Megakaryocytes undergo a unique differentiation program, becoming polyploid through repeated cycles of DNA synthesis without concomitant cell division. We have shown previously that phorbol 12-myristate 13-acetate (PMA) induces the Dami human megakaryocytic cell line to become polyploid and to express platelet-specific proteins, including von Willebrand factor (vWF) and glycoprotein Ib (GpIb). Phorbol esters are thought to regulate gene expression principally through the activation of protein kinase C (PKC), a family of structurally related kinases with potentially unique activation requirements and substrate specificities. A survey of PKC isoforms in Dami cells revealed that, by both Western and Northern analyses, PKC isoforms alpha, beta, delta, epsilon, eta, theta, and zeta were reproducibly detected. PKC-gamma was not detected. In order to define the role of individual PKC isoforms in megakaryocytic maturation, PMA and 2-deoxyphorbol 13-phenylacetate 20-acetate (dPPA), a putative selective activator of the PKC-beta 1 isotype, were compared for their effects on Dami cell maturation. Treatment with either dPPA or PMA caused Dami cells to cease proliferating, to become polyploid, and to express vWF. We also examined dPPA and PMA for their ability to activate and to downregulate expression of different PKC isoforms. Fifteen-minute treatment with PMA resulted in the translocation of PKC isoforms alpha, epsilon, and theta from the cytosolic to the membrane fraction; twenty-four hour treatment resulted in the downregulation of these isoforms. In contrast, dPPA was found to be a potent activator of PKC-epsilon alone and exhibited weaker effects on alpha and theta. These data suggest that PKC isoforms beta, delta, eta, and zeta, which appear not to be activated by either phorbol ester, are unlikely to be primarily involved in megakaryocytic maturation in response to these agents. The isoforms that are translocated by both phorbol esters-PKC isoforms alpha and theta, and particularly epsilon-are more likely to transduce the signals that stimulate Dami cell differentiation.

Widespread microsatellite instability occurs infrequently in adenocarcinoma of the gastric cardia

Heredity non-polyposis colorectal cancer (HNPCC) is associated with an increased predisposition to colorectal cancer and extra-colonic cancers of the gastro-intestinal, urological and female reproductive tracts. These tumours are characterised by an underlying defect in DNA mismatch repair and exhibit numerous replication errors throughout the genome (RER+ phenotype). HNPCC-associated gastric tumours, and a subset of sporadic, distally-located gastric tumours exhibit this RER+ phenotype. It is recognised that proximal and distal gastric tumours exhibit distinct epidemiological features. In this study we investigated the occurrence of microsatellite instability in a series of 38 primary gastric adenocarcinomas, arising in the proximal stomach. A total of 138 microsatellite markers, comprising mainly dinucleotide and tetranucleotide repeat units and covering all autosomal arms, excluding acrocentric arms, were analysed. One tumour demonstrated somatic microsatellite alterations at 62% (26 of 42) of loci tested. A further 32 tumours demonstrated levels of microsatellite instability ranging from 0.8% (1 of 28)-11.4% (15 of 132) of loci tested. Five tumours demonstrated no microsatellite alterations at any of the loci tested. These findings suggest that a high percentage of proximal gastric carcinomas exhibit a low level of microsatellite alterations at dinucleotide and tetranucleotide repeat loci. However, ubiquitous somatic alterations at these loci, characteristic of HNPCC-associated tumours, occur in a relatively small proportion of tumours.

Ubiquitous somatic alterations at microsatellite alleles occur infrequently in Barrett's-associated esophageal adenocarcinoma

Microsatellite alterations have been documented in a subset of sporadic tumors, including those of the colon, lung, bladder, stomach, and esophagus. This study documented the frequency of microsatellite alterations at 139 loci, comprising predominantly dinucleotide and tetranucleotide repeat units, in 17 cases of primary esophageal adenocarcinoma arising against a background of Barrett's metaplasia. Each tumor demonstrated alterations in at least one locus studied. Widespread microsatellite alterations, occurring at 45.3% (58 of 128) of loci tested, were detected in a single case. The remaining 16 tumors exhibited low levels of microsatellite instability, ranging from 0.8% (1 of 128) to 8.1% (10 of 123) of loci tested. The single case with ubiquitous somatic alterations showed no significant difference in the incidence of novel alleles at di- and tetranucleotide repeat loci. The 16 cases showing a low level of microsatellite alterations demonstrated a 3.3-fold higher incidence of novel alleles at tetranucleotide repeat loci compared to dinucleotide repeat loci. These data suggest that ubiquitous somatic alterations at microsatellite loci, considered a phenotypic expression of defective mismatch repair, occur infrequently in Barrett's-associated adenocarcinoma. However, the majority of these tumors demonstrate a low level of microsatellite alterations, perhaps reflecting the inherent instability of these markers.

Base transitions at CpG dinucleotides in the p53 gene are common in esophageal adenocarcinoma

This study examined the association between 17p allelic loss and p53 gene mutation in a series of 16 esophageal adenocarcinomas arising on a background of Barrett's esophagus. Two highly polymorphic dinucleotide repeat polymorphisms mapping to 17p13 were analyzed to assess the frequency of 17p allelic loss in these tumors. Mutations in the p53 gene were detected by direct DNA sequencing. Ninety-four % (15 of 16) of samples were informative at one or both polymorphic loci. Allelic loss at one or both loci was detected in 80% (12 of 15) of samples. Mutations were detected in 69% (11 of 16) esophageal adenocarcinomas, and there was a close association between 17p allelic loss and p53 gene mutation (P = 0.00879; Fisher's Exact Test). The tumors that were analyzed demonstrated a specific p53 mutation spectrum, with G:C to A:T base transitions at CpG dinucleotides accounting for 80% (8 of 10) of single-base substitutions. In three cases, the same p53 mutation was detected in both high-grade dysplasia and adjacent tumor. These results indicate that p53 gene alterations contribute to the development of esophageal adenocarcinoma and precede the development of invasive carcinoma in patients with Barrett's esophagus.

Elevated cyclic AMP inhibits endothelial cell synthesis and expression of TNF-induced endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1, but not intercellular adhesion molecule-1

We have investigated the role of cAMP as a signal transducer for TNF-induction of leukocyte adhesion molecule expression in cultured human umbilical vein endothelial cells (EC). Forskolin, a stimulator of adenylate cyclase, either alone or in combination with isobutyl methylxanthine (IBMX), an inhibitor of phosphodiesterase, fails to induce expression of endothelial leukocyte adhesion molecule 1 (ELAM-1 or E-selectin), of vascular cell adhesion molecule 1 (VCAM-1) or of intercellular adhesion molecule 1 (ICAM-1 or CD54). Unexpectedly, this combination of cAMP-elevating drugs inhibits TNF induction of ELAM-1 and VCAM-1 but not ICAM-1 expression. Similar results were observed with the membrane-permeant cAMP mimetics 8 bromoadenosine 3':5' cyclic monophosphate (8Br-cAMP) and N(6)2'-O-dibutyryladenosine 3':5'-cyclic monophosphate. Inhibition was greater at lower TNF concentrations (< 10 U/ml), at higher 8 Br-cAMP concentrations (> 100 microM), and at early times (2 h). Forskolin plus IBMX selectively inhibits TNF-induced increases in ELAM-1 and VCAM-1 mRNA, indicating that the action of cAMP is to block synthesis of these molecules. TNF, through stimulation of prostaglandin synthesis, produces slight elevations in the levels of endothelial cAMP. However, these increases in cAMP appear too small compared to those induced by forskolin plus IBMX to inhibit adhesion molecule expression. Indeed, complete inhibition of the TNF-mediated rise in cAMP, achieved by blocking cyclooxygenase with indomethacin, does not alter ELAM-1 expression. We conclude that cAMP is neither an intracellular mediator nor a physiological regulator of TNF-induced adhesion molecule expression in EC. However, our findings suggest that pharmacological elevations of cAMP in EC, by inhibiting TNF-induced synthesis of ELAM-1 and VCAM-1, could serve to limit inflammation.

Elevated cyclic AMP inhibits endothelial cell synthesis and expression of TNF-induced endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1, but not intercellular adhesion molecule-1

We have investigated the role of cAMP as a signal transducer for TNF-induction of leukocyte adhesion molecule expression in cultured human umbilical vein endothelial cells (EC). Forskolin, a stimulator of adenylate cyclase, either alone or in combination with isobutyl methylxanthine (IBMX), an inhibitor of phosphodiesterase, fails to induce expression of endothelial leukocyte adhesion molecule 1 (ELAM-1 or E-selectin), of vascular cell adhesion molecule 1 (VCAM-1) or of intercellular adhesion molecule 1 (ICAM-1 or CD54). Unexpectedly, this combination of cAMP-elevating drugs inhibits TNF induction of ELAM-1 and VCAM-1 but not ICAM-1 expression. Similar results were observed with the membrane-permeant cAMP mimetics 8 bromoadenosine 3':5' cyclic monophosphate (8Br-cAMP) and N(6)2'-O-dibutyryladenosine 3':5'-cyclic monophosphate. Inhibition was greater at lower TNF concentrations (&lt; 10 U/ml), at higher 8 Br-cAMP concentrations (&gt; 100 microM), and at early times (2 h). Forskolin plus IBMX selectively inhibits TNF-induced increases in ELAM-1 and VCAM-1 mRNA, indicating that the action of cAMP is to block synthesis of these molecules. TNF, through stimulation of prostaglandin synthesis, produces slight elevations in the levels of endothelial cAMP. However, these increases in cAMP appear too small compared to those induced by forskolin plus IBMX to inhibit adhesion molecule expression. Indeed, complete inhibition of the TNF-mediated rise in cAMP, achieved by blocking cyclooxygenase with indomethacin, does not alter ELAM-1 expression. We conclude that cAMP is neither an intracellular mediator nor a physiological regulator of TNF-induced adhesion molecule expression in EC. However, our findings suggest that pharmacological elevations of cAMP in EC, by inhibiting TNF-induced synthesis of ELAM-1 and VCAM-1, could serve to limit inflammation.

Diagnostic rigid and flexible oesophagoscopy in carcinoma of the oesophagus: a comparison

BACKGROUND

Flexible oesophagoscopy is regarded as superior to rigid oesophagoscopy on the basis of perforation rates as an end point. This advantage may be more apparent than real because no comparison has been made in a diagnostic setting in patients with carcinoma of the oesophagus with both perforation rate and diagnostic efficacy as indices.

METHODS

A retrospective analysis was carried out on data on 336 diagnostic oesophagoscopies in patients with carcinoma of the oesophagus, comparing rigid with flexible oesophagoscopy.

RESULTS

Both rigid and flexible oesophagoscopies were performed without perforation when they were used for diagnosis only. Rigid biopsy achieved a diagnostic success rate of 99.3%, compared with 80.5% for flexible oesophagoscopy.

CONCLUSIONS

Diagnostic oesophagoscopy can be achieved without perforation with either instrument, but the chance of diagnosing carcinoma was significantly greater with the rigid instrument.

Cardiac dysrhythmia in total thoracic oesophagectomy. A prospective study

A prospective controlled randomized clinical study of 50 patients undergoing total thoracic oesophagectomy by one surgical team is described, in which one group of patients was given prophylactic digoxin and the other was not. The incidence of cardiac dysrhythmia in each group was compared. Fourteen (56%) of 25 patients digitalized, compared to 16 (64%) of 25 patients not digitalized, suffered cardiac dysrhythmia, with a total incidence of 30 patients (60%). The first onset of dysrhythmia occurred within 48 h in 89% of the patients who suffered this complication. These results indicate a high incidence of cardiac dysrhythmia in patients undergoing this operative procedure, which is not significantly reduced by prophylactic digitalization and which is likely to occur within 2 days of surgery.

Prophylactic digitalization fails to control dysrhythmia in thoracic esophageal operations

A prospective, controlled, randomized study of 80 patients undergoing esophageal operations was undertaken, in which one group of patients was given digoxin and the other was not. The incidence of cardiac dysrhythmia was compared in each group. Twenty-six patients underwent operation for benign disease. Equal numbers were digitalized or not and no dysrhythmias occurred. Fifty-four patients underwent operation for malignant disease. Of 26 in the group digitalized, 12 suffered dysrhythmia (46%). Of 28 not digitalized, 9 suffered dysrhythmia (32%). Overall, 39% of patients with malignant disease suffered a dysrhythmia compared with none with benign disease (p < 0.002 by chi 2).

The role of rigid oesophagoscopy in oesophageal carcinoma

The efficacy and safety of rigid oesophagoscopy in diagnostic and therapeutic settings in a consecutive series of 404 patients with oesophageal carcinoma were studied and compared to that for flexible oesophagoscopy in the same group. In addition, we examined the same parameters in a smaller group who had undergone radiotherapy with subsequent malignant stricturing. We performed 328 rigid procedures and 118 flexible procedures in a single regional surgical referral unit over a 7 year period. The combined perforation rate was 1.3%, with an overall mortality of 1% from 446 procedures. We conclude that rigid oesophagoscopy in the presence of carcinoma retains an important diagnostic and therapeutic role which can be achieved with low incidence of perforation in high-risk patients.

Iatrogenic hydrothorax complicated by reactive pleural effusion

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Herpes simplex virus type 1 gene UL13 encodes a phosphoprotein that is a component of the virion

The UL13 open reading frame of herpes simplex virus type 1 (HSV-1) has been expressed in insect cells by a recombinant baculovirus and in Escherichia coli. In the latter case, the UL13 gene was fused to the gene for glutathione S-transferase (GST) to allow high-level expression of an 80-kDa GST-UL13 fusion protein. Antibody raised against the fusion protein reacted specifically with the 55-kDa UL13 gene product expressed by the recombinant baculovirus. This antibody also recognized a late phosphoprotein in HSV-1-infected cell lysates and a component of purified HSV-1 virions, both with the same electrophoretic mobility as the baculovirus-expressed protein. The virion component was efficiently phosphorylated in vitro by a virion-associated protein kinase. Using the same antibody, the probable homolog of the UL13 gene product was identified in HSV-2-infected cells and purified virions.

Plastic bullets: significant risk of serious injury above the diaphragm

A series of 123 patients who attended a district general hospital in Belfast over a 14-year period from 1975, sustained 126 plastic bullet injuries, resulting in one death and several serious injuries. This report shows the significant association of serious injury and/or death from plastic bullets in which the impact is above diaphragmatic level.

Prophylactic digitalisation in pulmonary surgery

BACKGROUND

Prophylactic digoxin is widely used in patients undergoing pulmonary surgery to prevent or control cardiac arrhythmias, but whether it is helpful or not is uncertain.

METHODS

An open, controlled randomised prospective clinical study of 111 patients was undertaken to compare the incidence of cardiac arrhythmias in the 58 patients who received preoperative digoxin and the 53 who did not.

RESULTS

Cardiac arrhythmia occurred in half (29/58) of those given prophylactic digoxin and in 36% (19/53) of those who were not. The overall incidence of arrhythmia was 43%, with no statistically significant difference between the groups.

CONCLUSION

Cardiac arrhythmias remain an important complication of pulmonary surgery and the incidence is not reduced by prophylactic digoxin.

Basal cell carcinoma presenting with profound anaemia

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Massive tissue necrosis can be induced by heparin or warfarin

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Type III tibial fractures in the elderly: results of 23 fractures in 20 patients

A series of 23 type III fractures of the tibia in 20 elderly patients (over 60 years of age) presenting for combined plastic and orthopaedic surgical management over a period of 15 years are reviewed. Overall limb salvage was 53 per cent, with an average inpatient duration not significantly different from that for amputation, suggesting that an age of over 60 years is not necessarily a contraindication to attempts at limb salvage in type III injuries.

Tumor necrosis factor induction of endothelial cell surface antigens is independent of protein kinase C activation or inactivation. Studies with phorbol myristate acetate and staurosporine

We have investigated whether TNF-induced changes in human endothelial cell (EC) surface Ag expression are mediated by protein kinase C (PKC). This suggestion arose from the observations that PMA, a potent PKC activator, can mimic TNF by inducing expression of endothelial leukocyte adhesion molecule 1, intercellular adhesion molecule 1 (ICAM-1), and class I MHC molecules on human EC. However, in contrast to the actions of PMA, TNF neither causes membrane translocation of PKC nor induces the phosphorylation of the myristoylated alanine-rich C kinase substrate, two measures of PKC activation. Moreover, the PKC inhibitor staurosporine can block PMA-induced endothelial leukocyte adhesion molecule 1 expression at 4 h, but does not inhibit the actions of TNF. At 24 h, staurosporine itself induces intercellular adhesion molecule 1 and class I MHC, and acts additively with TNF. Twenty four hour treatment with PMA causes loss of PKC. We propose that at 24 h, staurosporine and PMA share a mechanism of action, namely diminution of PKC activity. However, 24 h treatment with TNF does not reduce the amount of PKC nor does it prevent activation of PKC by PMA. We conclude that TNF effects in EC are not mediated by PKC activation or inactivation.

Tumor necrosis factor induction of endothelial cell surface antigens is independent of protein kinase C activation or inactivation. Studies with phorbol myristate acetate and staurosporine

We have investigated whether TNF-induced changes in human endothelial cell (EC) surface Ag expression are mediated by protein kinase C (PKC). This suggestion arose from the observations that PMA, a potent PKC activator, can mimic TNF by inducing expression of endothelial leukocyte adhesion molecule 1, intercellular adhesion molecule 1 (ICAM-1), and class I MHC molecules on human EC. However, in contrast to the actions of PMA, TNF neither causes membrane translocation of PKC nor induces the phosphorylation of the myristoylated alanine-rich C kinase substrate, two measures of PKC activation. Moreover, the PKC inhibitor staurosporine can block PMA-induced endothelial leukocyte adhesion molecule 1 expression at 4 h, but does not inhibit the actions of TNF. At 24 h, staurosporine itself induces intercellular adhesion molecule 1 and class I MHC, and acts additively with TNF. Twenty four hour treatment with PMA causes loss of PKC. We propose that at 24 h, staurosporine and PMA share a mechanism of action, namely diminution of PKC activity. However, 24 h treatment with TNF does not reduce the amount of PKC nor does it prevent activation of PKC by PMA. We conclude that TNF effects in EC are not mediated by PKC activation or inactivation.

Assay of HIV-1 proteinase: a colorimetric method using small peptide substrates

A colorimetric assay for HIV proteinase using small protected peptide substrates is described. Substrates are cleaved to release N-terminal prolyl peptides which react with isatin to form a blue product which is measured spectrophotometrically. The assay is suitable for use with pure enzyme or crude extracts derived from genetically engineered Escherichia coli.