The distribution of phosphodiesterase 2A in the rat brain

The phosphodiesterases (PDEs) are a superfamily of enzymes that regulate spatio-temporal signaling by the intracellular second messengers cAMP and cGMP. PDE2A is expressed at high levels in the mammalian brain. To advance our understanding of the role of this enzyme in regulation of neuronal signaling, we here describe the distribution of PDE2A in the rat brain. PDE2A mRNA was prominently expressed in glutamatergic pyramidal cells in cortex, and in pyramidal and dentate granule cells in the hippocampus. Protein concentrated in the axons and nerve terminals of these neurons; staining was markedly weaker in the cell bodies and proximal dendrites. In addition, in both hippocampus and cortex, small populations of non-pyramidal cells, presumed to be interneurons, were strongly immunoreactive. PDE2A mRNA was expressed in medium spiny neurons in neostriatum. Little immunoreactivity was observed in cell bodies, whereas dense immunoreactivity was found in the axon tracts of these neurons and their terminal regions in globus pallidus and substantia nigra pars reticulata. Immunostaining was dense in the medial habenula, but weak in other diencephalic regions. In midbrain and hindbrain, immunostaining was restricted to discrete regions of the neuropil or clusters of cell bodies. These results suggest that PDE2A may modulate cortical, hippocampal and striatal networks at several levels. Preferential distribution of PDE2A into axons and terminals of the principal neurons suggests roles in regulation of axonal excitability or transmitter release. The enzyme is also in forebrain interneurons, and in mid- and hindbrain neurons that may modulate forebrain networks and circuits.

Accuracy of radiological staging in identifying high-risk colon cancer patients suitable for neoadjuvant chemotherapy: a multicentre experience

AIM

A pilot study was undertaken to determine the accuracy of computed tomography (CT) staging in identifying patients with high-risk colon cancers who would be considered as candidates for a neoadjuvant therapy trial (FOxTROT) and those at low risk (T1/T2) who would be excluded.

METHOD

Participating radiologists from 19 centres attended workshops for standardization of image interpretation according to previously defined prognostic criteria: good prognosis tumours, including, T1/T2; intermediate prognosis, T3 < 5 mm tumour invasion beyond the muscularis propria (MP); and poor prognosis tumours, including T3 with tumour extension ≥ 5 mm beyond the MP or T4. The CT findings were compared with histopathology as the reference standard.

RESULTS

Of 94 patients with radiological and pathological data, 71% were categorized by CT as having a poor prognosis. The sensitivity and specificity of CT in identifying these tumours were 87% (95% CI, 74-94) and 49% (95% CI, 33-65). Sensitivity and specificity for tumour infiltration beyond the MP (T3/T4 vs T1/T2) were 95% (95% CI, 87-98) and 50% (95% CI, 22-77), respectively. Including all CT-staged T3 and T4 patients in the trial would have increased the proportion eligible for entry to 89% (n = 84) without affecting the false-positive rate of 7%. Some 20% of T3/T4 patients would have been ineligible for FOxTROT because of synchronous metastases.

CONCLUSION

In a multicentre setting, CT scanning identified high-risk (T3/4) colon cancers with minimal overstaging of T1/T2 tumours, thus establishing the feasibility of radiologically guided neoadjuvant chemotherapy.

A critical review of the effectiveness of rodent pharmaceutical carcinogenesis testing in predicting for human risk

The pharmaceutical industry and regulatory agency toxicology testing paradigms in the United States currently appear successful, in part because of the continuously increasing life expectancy and the declining age-adjusted cancer rates in the United States. Although drugs likely have a minimal impact on the population statistics for cancer rates, pharmaceutical pathologists and toxicologists must focus on the individual risk for pharmaceutical carcinogenesis. As our understanding of carcinogenesis increases exponentially, and after hundreds if not thousands of rodent cancer tests, significant improvement in the precision of human pharmaceutical carcinogenesis hazard identification should now be possible and would enable a reduction in the substantial false-negative and false positive-rates reported herein. The appropriate use of acute, subchronic, chronic, and special toxicology tests to identify the major associated cancer risk factors, specifically, hormonal modulation, immunosuppression, genetic toxicity, and chronic toxicity, can be recognized through this review of pharmaceutical carcinogens. Significant opportunities exist for improving the effectiveness and efficiency of the current cancer risk assessment paradigm.

Effect of ion Bombardment in Polymer Surface Modification: Comparison of Pulsed High Frequency Plasma and ion Beam

The energy and the flux of impinging ions are important factors which determine the properties of deposited films and of exposed surfaces (microstructure, density, hardness, roughness, stress, chemical structure, adhesion etc.). In the present work, we use a multigrid retarding field analyzer to study ion bombardment characteristics in two different systems: a pulsed microwave plasma reactor, and a cold cathode ion source. We have found that the ion energy distribution functions (IEDF) possess specific features for each mode of operation: we evaluate the shape and the maximum and the mean ion energies of the IEDF for different gases such as Ar and N2. These ion characteristics are correlated with surface restructuring of differently treated polymers (polycarbonate and polyethylene terephthalate), analyzed by XPS.

Step by step on a piece of string: an illustration of community work as a social health strategy

This article describes the development of a community work approach to the problem of isolation within a semi-rural and urban community. Reasons for adopting a community work emphasis within this community health service are explained. Two projects which illustrate ways in which the approach was put into practice are described and implications and issues for health workers are discussed using community participation, empowerment, and co-ordination of services as a basis for discussion.

Mood state and melanoma outcome in the Multicenter Selective Lymphadenectomy Trial

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Background: Emotional state has been linked to cancer survival, but its influence on the outcome of early melanoma is unclear. The Multicenter Selective Lymphadenectomy Trial (MSLT-I) randomized patients with clinically localized cutaneous melanoma to wide local excision (WEX) plus observation or to WEX plus sentinel lymph node biopsy (SNB). Clinical endpoints included disease-specific and disease-free survival. A substudy of this phase III trial evaluated the impact of mood state on survival, and the impact of recurrence on mood state. Methods: Patients were asked to complete a 65-question form within 6 months of enrollment (baseline) and every 12 months thereafter. This questionnaire measured 6 identifiable mood states (vigor-activity, tension-anxiety, depression, anger-hostility, fatigue-inertia, confusion-bewilderment) of the Profile of Mood States (POMS), a validated mood scale for assessing responses to therapy. Self-reported data from the questionnaires were linked to demographic and clinical variables. Results: Of 2,001 patients accrued to MSLT-I, 1,620 completed the questionnaire at baseline. The baseline distribution of POMS variables was similar in the two treatment arms (data not shown). Patients with more vigor at baseline had a significantly longer disease-free and overall survival ( Table ), even after adjusting for age, tumor thickness, site, and ulceration status (p <0.001). Among 136 patients who completed a questionnaire within 6 months after recurrence, comparison of baseline and post-recurrence responses revealed significant changes in mood state: tension, fatigue and confusion increased, whereas vigor decreased (p = 0.0004, 0.0171, 0.0089, and 0.0028, respectively). Conclusions: Vigor, a measure of energy and optimism, is directly correlated with disease-free and overall survival in early melanoma. The negative impact of recurrence on mood state suggests that SNB as a tool for preventing recurrence might also improve mood state and psychological well-being. Supported by NIH CA29605. [Table: see text]

No significant financial relationships to disclose.

The 2008 ACVP role delineation survey and initial data analysis: from the Role Delineation Task Force

The American College of Veterinary Pathologists commissioned a role delineation survey to define the specialized tasks, knowledge, and tools that define the current practice of veterinary clinical pathology and veterinary anatomic pathology. The survey also identified when competence was acquired for each task (i.e., before certification or after certification). The response rate by diplomates was high, with approximately 50% of practicing pathologists within each specialty responding to each survey. Using the survey results, all tasks for each specialty were classified as either appropriate or unsuitable for testing in the certifying examinations. The role delineation survey data will facilitate the creation of test plans that objectively define the content in each certifying examination, the evaluation and enhancement of training curricula, and the optimization of continuing education opportunities for practicing veterinary pathologists.

Patient experiences of colonoscopy, barium enema and CT colonography: a qualitative study

Previous studies of patient experience with bowel screening tests, in particular CT colonography (CTC), have superimposed global rating scales and not explored individual experience in detail. To redress this, we performed qualitative interviews in order to characterize patient expectations and experiences in depth. Following ethical permission, 16 patients undergoing CTC, 18 undergoing colonoscopy and 15 undergoing barium enema agreed to a semi-structured interview by a health psychologist. Interviews were recorded, responses transcribed and themes extracted with the aim of assimilating individual experiences to facilitate subsequent development and interpretation of quantitative surveys of overall satisfaction with each diagnostic test. Transcript analysis identified three principal themes: physical sensations, social interactions and information provision. Physical sensations differed for each test but were surprisingly well tolerated overall. Social interactions with staff were perceived as very important in colouring the whole experience, particularly in controlling the feelings of embarrassment, which was critical for all procedures. Information provision was also an important determinant of experience. Verbal feedback was most common during colonoscopy and invariably reassuring. However, patients undergoing CTC received little visual or verbal feedback and were often confused regarding the test outcome. Barium enema had no specific advantage over other tests. Qualitative interviews provided important perspectives on patient experience. Our data demonstrated that models describing the quality of medical encounters are applicable to single diagnostic episodes. Staff interactions and information provision were particularly important. We found advantages specific to both CTC and colonoscopy but none for barium enema. CTC could benefit greatly from improved information provision following examination.

Selecting patients with young-onset colorectal cancer for mismatch repair gene analysis

Background

Young patients with colorectal cancer are at increased risk of carrying a germline mutation in mismatch repair (MMR) genes. This study investigated the role of clinical criteria and immunohistochemistry for MMR proteins in selecting young patients for mutation testing.

Methods

A cohort of 56 consecutive patients with colorectal cancer aged less than 45 years were stratified into three groups based on clinical criteria: ‘Amsterdam criteria’, ‘high risk’ and ‘young onset only’. Immunohistochemistry for four MMR proteins was carried out and the rate of compliance with clinical guidelines determined.

Results

Tumours from 11 patients (20 per cent) had abnormal MMR protein expression, of whom eight were referred for genetic assessment. Of 21 patients (38 per cent) in total referred to the genetics unit, six MMR gene mutations were identified, all associated with abnormal immunohistochemistry.

Conclusion

MMR immunohistochemistry should be considered routine in young-onset colorectal cancer.

Improved long-term survival in patients with intermediate thickness primary melanoma managed by sentinel node biopsy

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Background: Although improved disease-free survival (DFS) with sentinel node biopsy (SNB) for clinically localized melanoma was observed at the interim analysis from the first Multicenter Selective Lymphadenectomy Trial (MSLT-I) there was not yet an improvement in overall survival (OS). We hypothesize this was due to the few observed early deaths. To investigate this we simulated the MSLT-1 protocol using our institutional database. Methods: 3,800 patients undergoing wide excision with or without SNB were matched by primary stage/ulceration/site and patient demographics. Patients with positive sentinel nodes (SN) underwent immediate completion lymphadenectomy (CLND) whereas non-SNB patients managed by nodal observation underwent delayed CLND at nodal recurrence. Survival was determined by the Kaplan-Meier method. Significance was determined using log-rank and Cox regression analysis. Results: Among matched pairs of SNB and non-SNB patients with 1.2–3.5 mm primaries, projected 10-year OS was 76% with SNB versus 63% without SNB (p=0.0008). There was no corresponding statistically significant difference between all 2001 SNB patients and 1799 non-SNB patients, or within the thin primary and thicker primary groups. By multivariate analysis, only SN status (p<0.0001), Breslow thickness (p<0.0001) and ulceration (p=0.0001) were independently predictive of OS. Conclusions: Our long-term data suggest that performing SNB will improve OS in patients with intermediate thickness melanoma but not with thicker or thinner melanomas as compared to observation and delayed CLND.

No significant financial relationships to disclose.

[Table: see text]

CT colonography: interpretative performance in a non-academic environment

AIM

To investigate interpretative accuracy and reporting time for radiologists performing computed tomography (CT) colonography in day-to-day non-academic clinical practice.

MATERIALS AND METHODS

Thirteen radiologists from seven centres, who were reporting CT colonography in non-academic daily clinical practice, interpreted a dataset of 15 colonoscopically validated cases in a controlled environment. Ten cases had either a cancer or polyp >10mm; one case had a medium polyp and four were normal. Correct case categorization and interpretation times were compared using analysis of variance to aggregated results obtained from both experienced observers and observers recently trained using 50 cases, working in an academic environment. The effect of experience was determined using Spearman's rank correlation.

RESULTS

Individual accuracy was highly variable, range 53% (95% CI 27-79%) to 93% (95% CI 68-100%). Mean accuracy overall was significantly inferior to experienced radiologists (mean 75 versus 88%, p=0.04) but not significantly different from recently trained radiologists (p=0.48). Interpretation time was not significantly different to experienced readers (mean 12.4 min versus 11.7, p=0.74), but shorter than recently trained radiologists (p=0.05). There was a significant, positive, linear correlation between prior experience and accuracy (p<0.001) with no plateau.

CONCLUSION

Accuracy for sub-specialist radiologists working in a non-academic environment is, on average, equivalent to radiologists trained using 50 cases. However, there is wide variability in individual performance, which generally falls short of the average performance suggested by meta-analysis of published data. Experience improves accuracy, but alone is insufficient to determine competence.

Desmocollin switching in colorectal cancer

The desmocollins are members of the desmosomal cadherin family of cell-cell adhesion molecules. They are essential constituents of desmosomes, intercellular junctions that play a critical role in the maintenance of tissue integrity in epithelia and cardiac muscle. In humans, three desmocollins (Dsc1, Dsc2 and Dsc3) have been described. The desmocollins exhibit tissue-specific patterns of expression; only Dsc2 is expressed in normal colonic epithelium. We have found switching between desmocollins in sporadic colorectal adenocarcinoma with a reduction in Dsc2 protein (in 8/16 samples analysed by immunohistochemistry) being accompanied by de novo expression of Dsc1 (16/16) and Dsc3 (7/16). Similar results were obtained by western blotting of a further 16 samples. No change was found in Dsc2 mRNA, but de novo expression of Dscs 1 and 3 was accompanied by increased message levels. Loss of Dsc2 (8/19) and de novo expression of Dsc1 (11/19) and Dsc3 (6/19) was also found in colorectal adenocarcinomas on a background of colitis. The data raise the possibility that switching of desmocollins could play an important role in the development of colorectal cancer.

Chemokine receptor 5 (CCR5) Δ32 base pair somatic gene deletions from PBM predict survival of patients with advanced stage (IV) melanoma

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Background: Chemokines are a family of secreted chemotactic cytokines that function in leukocyte trafficking and activation. Chemokine receptor 5 (CCR5) is involved in CD4+ T-cell mediated immunity and dendritic cell (DC) activation. A 32 base pair (bp) deletion mutation on chromosome 3p21 result in a non-functional CCR5 with defective immunity. We hypothesized that CCR5Δ32 bp mutations would result in a diminished immune response to melanoma and maybe predictive of outcome of patients with advanced-stage disease. Methods: We identified 160 AJCC stage IV melanoma patients from our database whom had been made NED (no evidence of disease) by surgical resection. 105 (66%) had received active specific immunotherapy in phase I/II trials. Genomic DNA was extracted from peripheral blood mononuclear cells (PBM) and screened by PCR for the presence of CCR5Δ32 bp deletions. PCR products were sequenced to verify the result. Statistical analysis was performed by using Log-rank, Chi-square & Student’s t-test. Results: Of 160 patients, 100 (63%) were men. Ages ranged from 19–82 (median 47 yrs.). 46 (29%) patients had M1a, 48 (30%) Mlb and 66 (41%) Mlc stage of metastases prior to surgical resection. Median follow-up was 47.5 mos. 135 (84%) patients had wild-type (Wt)CCR5 gene; 21 (13%) had heterozygous (HtM) and 4(3%) had homozygous mutations (HoM). 5-yr survival was significantly higher for patients with CCR5 Wt than those with HtM or HoM deletions (55.6%±6.1% vs. 21.4%±10.8%, p=0.031). None of the 21 patients with HtM survived 10yrs. Multivariate analyses demonstrated only CCR5 gene status (Wt vs. HtM/HoM) as predictive of survival (p=0.007). Age (p=0.23), gender (p=0.38), and M stage (M1a vs. M1b/c) (p=0.31) were not important in the statistical model. When immunotherapy responses (+ vs. -) were included in the model both responses and CCR5 mutation status were significant (p=0.0021, p=0.0063 respectively). Conclusions: Our results suggest CCR5Δ32bp somatic mutations from PBM are present in advanced-stage melanoma patients and are highly predictive of survival. Functional CCR5 may be used as a selection factor for surgery but more importantly essential for either active immunotherapy or the natural immune response to be effective for these patients.

No significant financial relationships to disclose.