Endoscopic ultrasound-guided fine-needle aspiration biopsy coupled with KRAS mutation assay to distinguish pancreatic cancer from pseudotumoral chronic pancreatitis

BACKGROUND AND STUDY AIMS

Differential diagnosis between pancreatic adenocarcinoma (PADC) and pseudotumoral forms of chronic pancreatitis remains difficult. Mutation of KRAS oncogene is present in 75% to 95% of PADC. This study aimed to evaluate whether the combined analysis of KRAS mutation with cytopathological findings from endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) might improve discrimination between PADC and chronic pancreatitis.

PATIENTS AND METHODS

This prospective multicenter study included 178 patients with solid pancreatic masses (men 104, women 74; mean age 64.5 years). Cytopathological examination and KRAS mutation analysis (codon-12 and codon-13, restriction fragment length polymorphism [RFLP] and direct sequencing) were performed on EUS-FNAB material. Final diagnoses were obtained on EUS-FNAB analysis and/or a second biopsy and/or clinical follow-up and/or surgery: PADC, n = 129; chronic pancreatitis, n = 27; other pancreatic neoplasms, n = 16; and benign lesions, n = 6.

RESULTS

KRAS status analysis was successful in all EUS-FNAB samples. Codon-12 KRAS point mutation was found in 66% of PADC samples. No case of chronic pancreatitis displayed KRAS mutation. Sensitivity, specificity, positive and negative predictive values, and overall accuracy of cytopathology alone for diagnosis of PADC versus chronic pancreatitis were 83%, 100%, 100%, 56% and 86%, respectively. When KRAS mutation analysis was combined with cytopathology, these values reached 88%, 100%, 100%, 63% and 90% respectively.

CONCLUSION

Although the value of KRAS analysis in addition to EUS-FNAB is limited for distinguishing pancreatic mass lesions, when chronic pancreatitis presented as a pseudotumor a negative finding (wild-type KRAS), was useful in strongly suggesting a benign lesion.

Modulation of social interactions by immune stimulation in honey bee, Apis mellifera, workers

Background

Immune response pathways have been relatively well-conserved across animal species, with similar systems in both mammals and invertebrates. Interestingly, honey bees have substantially reduced numbers of genes associated with immune function compared with solitary insect species. However, social species such as honey bees provide an excellent environment for pathogen or parasite transmission with controlled environmental conditions in the hive, high population densities, and frequent interactions. This suggests that honey bees may have developed complementary mechanisms, such as behavioral modifications, to deal with disease.

Results

Here, we demonstrate that activation of the immune system in honey bees (using bacterial lipopolysaccharides as a non-replicative pathogen) alters the social responses of healthy nestmates toward the treated individuals. Furthermore, treated individuals expressed significant differences in overall cuticular hydrocarbon profiles compared with controls. Finally, coating healthy individuals with extracts containing cuticular hydrocarbons of immunostimulated individuals significantly increased the agonistic responses of nestmates.

Conclusion

Since cuticular hydrocarbons play a critical role in nestmate recognition and other social interactions in a wide variety of insect species, modulation of such chemical profiles by the activation of the immune system could play a crucial role in the social regulation of pathogen dissemination within the colony.

Social management of LPS-induced inflammation in Formica polyctena ants

Invertebrates, and especially insects, constitute valuable and convenient models for the study of the evolutionary roots of immune-related behaviors. With stable conditions in the nest, high population densities, and frequent interactions, social insects such as ants provide an excellent system for examining the spread of pathogens. The evolutionary success of these species raises questions about the behavioral responses of social insects to an infected nestmate. In this experiment, we tested the behavioral changes of the red wood ant Formica polyctena toward an immune-stimulated nestmate. We used bacterial endotoxin (lipopolysaccharides, LPS) to active the innate immune system of individual worker ants without biasing our observation with possible cues or host-manipulation from a living pathogen. We show that LPS-induced immune activation in ants triggers behavioral changes in nestmates. Contrary to what would be expected, we did not find removal strategies (e.g. agonistic behaviors) or avoidance of the pathogenic source, but rather a balance between a limitation of pathogen dissemination (i.e. decreased trophallaxis and locomotion of the LPS-treated ant), and what could constitute the behavioral basis for a "social vaccination" (i.e. increased grooming). This supports the importance of social interactions in resistance to disease in social insects, and perhaps social animals in general.

Comorbidities and Charlson score in resected stage I nonsmall cell lung cancer

Patients with nonsmall cell lung cancer (NSCLC) have been shown to have a higher prevalence of comorbidity associated with age and tobacco consumption. The objective of the present study was to determine the impact of comorbidity on survival after surgery of stage I NSCLC. In total, 588 consecutive patients operated on for a pathological stage I NSCLC between January 1, 1979 and December 31, 2003 were studied. Comorbidities were analysed individually. Overall comorbidity was assessed using the Charlson index of comorbidity (CCI). Survival data were collected for each patient from the date of operation, with a median duration of follow-up of 104 months. Survival analyses and Cox proportional hazards model analyses were used. The mean age of patients was 62.7 yrs, and 529 (89%) patients were male. The distribution of overall comorbidity severity was as follows. CCI grade 0: 47.1%; grade 1-2: 43.7%; grade 3-4: 8.3%; and grade > or =5: 0.8%. The 2, 3 and 5 yrs survival were 69, 62 and 50%, respectively. Multivariable analysis showed that T stage, age, a concomitant history of moderate-to-severe liver disease, a past history of cured cancer, cerebrovascular disease and CCI were independent predictors of survival (Hazard Ratio for CCI grade >2: 1.81; 95% confidence interval 1.25-2.63). In conclusion, comorbidity has a significant impact on survival after surgical resection of patients with stage I nonsmall cell lung cancer. The use of a validated index of comorbidity in prognostic analyses of resected nonsmall cell lung cancer is recommended.

Protection against Leptospira interrogans sensu lato challenge by DNA immunization with the gene encoding hemolysin-associated protein 1

The use of DNA constructs encoding leptospiral proteins is a promising new approach for vaccination against leptospirosis. In previous work we determined that immunization with hemolysis-associated protein 1 (Hap1) (LipL32) expressed by adenovirus induced significant protection against a virulent Leptospira challenge in gerbils. To avoid the use of the adenovirus vector, we checked for clinical protection against lethal challenge by DNA vaccination. A DNA vaccine expressing Hap1 was designed to enhance the direct gene transfer of this protein into gerbils. A challenge was performed 3 weeks after the last immunization with a virulent strain of serovar canicola. Our results show that the cross-protective effect with pathogenic strains of Leptospira, shared by Hap1, could be mediated by the DNA plasmid vector. This finding should facilitate the design and development of a new generation of vaccines against bacteria, particularly Leptospira interrogans sensu lato.

Ethological validation and the assessment of anxiety-like behaviours: methodological comparison of classical analyses and structural approaches

The research on emotional reactivity usually implies the use of standardised behavioural tests that provide a quick idea of the effect of a treatment on the reactivity of subjects to potentially dangerous situations. Many validity criteria have been considered to evaluate these tests. This validity concept supports the idea that animals' behaviour in these tests model human anxiety. Generally, those criteria repeatedly labelled as "ethological validation" refer to the analogy between animals and human in the meaning of the test situation. Although the content of the ethological validation concept is heterogeneous, it is steadily related to a fixed interpretation of the behavioural items produced in a given experimental setting. The basic assumption of such reasoning is that the behavioural items would always be expressed in the same behavioural context whatever the subject, its gender, strain or species, thoroughly asserting a predefined subjective state. Using multivariate and textual analysis, we found evidence that the "ethological validation" recourse to an a priori interpretation for a given behavioural variable may be deceptive. We defend the idea that the meaning of a behavioural variable should be restricted to the general context where it arose. Theoretical propositions and methodological options are discussed.

Susceptibility to subchronic unpredictable stress is related to individual reactivity to threat stimuli in mice

As in many complex behavioral responses, inter-individual variability can be observed in the responses to a chronic mild stress. While some subjects exhibit more resilient behaviours, others appear more susceptible to stress. This study hypothesizes that this variability relies on the individual appraisal of the stressful event. To study this assumption, mice were first subjected to a conditioned task occurring in a circular arena. In this task, a mild air-puff (i.e. stressor) in a given quadrant of the arena was coupled with the presence or the absence of a light in the same quadrant. Half of mice were then submitted to a 15-day subchronic stress consisting in various environmental and social mild stressors randomly applied two or three times a day. At the end of this procedure, the occurrence of depressive-like behaviours in stressed mice was assessed using measures of the stress regime (i.e. physical state, choice test, grooming test). The physical state assessed the physical appearance of mice. The grooming test consisted in measuring the time spent in grooming after mice were sprayed upon with a viscous solution. The choice test consisted in measuring the time spent in an uncomfortable place (i.e. whose floor was covered with damp sawdust) versus a more comfortable one (i.e. with dry sawdust) to evaluate the reactivity to a negative stimulus previously encountered during the subchronic stress. Multiple regression analyses revealed a relationship between attention toward salient stressful stimuli in the conditioned task and susceptibility to the subchronic stress procedure. These results are discussed regarding their relevance for the understanding of aetiologies of depressive illnesses.

Modelling of the coupling between brain electrical activity and metabolism

In order to make an attempt at grouping the various aspects of brain functional imaging (fMRI, MRS, EEG-MEG, ...) within a coherent frame, we implemented a model consisting of a system of differential equations, that includes: (1) sodium membrane transport, (2) Na/K ATPase, (3) neuronal energy metabolism (i.e. glycolysis, buffering effect of phosphocreatine, and mitochondrial respiration), (4) blood-brain barrier exchanges and (5) brain hemodynamics, all the processes which are involved in the activation of brain areas. We assumed that the correlation between brain activation and metabolism could be due to either changes in the concentrations of ATP and ADP following activation of Na/K ATPase that result from the changes in ion concentrations, or the involvement, in different phases of metabolism, of a second messenger such as calcium. In this article, we show how this type of model enables interpretation of MRS and fMRI published data that were obtained during prolonged stimulations.

Identification of the hemolysis-associated protein 1 as a cross-protective immunogen of Leptospira interrogans by adenovirus-mediated vaccination

New vaccine strategies are needed for the prevention of leptospirosis, a widespread human and animal disease caused by pathogenic leptospires. Our previous work determined that a protein leptospiral extract conferred cross-protection in a gerbil model of leptospirosis. The 31- to 34-kDa protein fraction of Leptospira interrogans serovar autumnalis was shown sufficient for this purpose. In the present study, N-terminal sequencing of a 32-kDa fraction and Southern blotting of genomic DNA with corresponding degenerated oligonucleotide probes identified two of its constituents: hemolysis-associated protein 1 (Hap1) and the outer membrane Leptospira protein 1 (OmpL1). Adenovirus-mediated Hap1 vaccination induces significant protection against a virulent heterologous Leptospira challenge in gerbils, whereas a similar OmpL1 construct failed to protect the animals. These data indicate that Hap1 could be a good candidate for developing a new generation of vaccines able to induce broad protection against leptospirosis disease.

Hes1 and Hes5 activities are required for the normal development of the hair cells in the mammalian inner ear

The mammalian inner ear contains two sensory organs, the cochlea and vestibule. Their sensory neuroepithelia are characterized by a mosaic of hair cells and supporting cells. Cochlear hair cells differentiate in four rows: a single row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs). Recent studies have shown that Math1, a mammalian homolog of Drosophila atonal is a positive regulator of hair cell differentiation. The basic helix-loop-helix (bHLH) genes Hes1 and Hes5 (mammalian hairy and Enhancer-of-split homologs) can influence cell fate determination by acting as negative regulators to inhibit the action of bHLH-positive regulators. We show by using reverse transcription-PCR analysis that Hes1, Hes5, and Math1 are expressed in the developing mouse cochleae. In situ hybridization revealed a widespread expression of Hes1 in the greater epithelial ridge (GER) and in lesser epithelial ridge (LER) regions. Hes5 is predominantly expressed in the LER, in supporting cells, and in a narrow band of cells within the GER. Examination of cochleae from Hes1(-/-) mice showed a significant increase in the number of IHCs, whereas cochleae from Hes5(-/-) mice showed a significant increase in the number of OHCs. In the vestibular system, targeted deletion of Hes1 and to a lesser extent Hes5 lead to formation of supernumerary hair cells in the saccule and utricle. The supernumerary hair cells in the mutant mice showed an upregulation of Math1. These data indicate that Hes1 and Hes5 participate together for the control of inner ear hair cell production, likely through the negative regulation of Math1.

[Fascioliasis of the common bile duct: endoscopic ultrasonographic diagnosis and endoscopic sphincterotomy]

Two cases of biliary fasciolasis are reported. The patients presented with biliary pain and/or acute pancreatitis. Pre-operative ultrasound endoscopy showed main bile duct dilation and linear elongated echogenic structures in the common bile duct lumen. Endoscopic retrograde cholangiography and endoscopic sphincterotomy were performed. Parasites were endoscopically removed resulting in disappearance of symptoms and biological abnormalities. Serological tests and pathological examination confirmed the presence of Fasciola hepatica. During follow-up, stool examination failed to show any Fasciola hepatica eggs, and in one case, serology became negative. This report emphasizes the value of ultrasound endoscopy in the diagnosis of unsuspected biliary fasciolasis. This report also confirms the therapeutic role of endoscopic sphincterotomy in patients with obstructive biliary fasciolasis.

Assessment of complications of EUS-guided fine-needle aspiration

BACKGROUND

EUS-guided fine-needle aspiration (EUS-FNA) permits both morphologic and cytologic analysis of lesions within or adjacent to the GI tract. Despite increasing use of this technique, the safety and overall complication rates remain poorly defined.

METHODS

During a period of 20 months, 322 consecutive patients underwent EUS-FNA in 2 centers. All procedures were performed with the patients under general anesthesia. All complications (including local complications resulting from endoscopy/aspiration or clinical complications after the procedure) were evaluated. Potential risk factors for the development of complications were also analyzed including site and nature of the lesion, presence of portal hypertension, and number of needle passes.

RESULTS

A total of 345 lesions were aspirated in 322 patients. EUS-FNA involved the pancreas in 248 cases. Pancreatic lesions included solid (134) and cystic (114) types, which required a mean of 2.5 and 1.4 needle passes, respectively. Complications were observed in 4 (1.2%) patients after aspiration of pancreatic cystic lesions (acute pancreatitis, n = 3; aspiration pneumonia, n = 1) and all cases of pancreatitis resulted from FNA of lesions in the head/uncinate process. No complications resulted from FNA of solid pancreatic lesions. Complications were not observed after FNA of lymph nodes (n = 62) and one case of aspiration pneumonia was observed after FNA of a stromal tumor. EUS-FNA was performed without complication in 16 patients (5%) with portal hypertension. The number of needle passes was not predictive of complications.

CONCLUSIONS

Because the overall risk of complications from EUS-FNA was relatively low (1.6%) with no severe or fatal incidents and although the risk appears slightly higher than that for standard EUS alone, the safety of EUS-FNA appears acceptable based on this analysis from an experienced center.