mGlu and NMDA receptor contributions to capsaicin-induced thermal and mechanical hypersensitivity

Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors, some of which are localized in the spinal cord dorsal horn, and are involved with pain perception. The anti-nociceptive effects of intrathecal (i.t.) pretreatment with various mGlu receptor agonists and antagonists were assessed in Long Evans rats with mechanical and thermal hypersensitivity after sub-dermal injection of capsaicin in the hindpaw. Selective group II (aminopyrrolidine-2R,4R-dicarboxylate, APDC) and group III (l-2-amino-4-phosphonobutyrate, L-AP4) agonists, as well as selective mGlu(1) (1-aminoindan-1,5(R,S)-dicarboxylic acid, AIDA) and mGlu(5) (2-methyl-6-(phenylethynyl)-pyridine, MPEP) receptor subtype antagonists were compared with that of an NMDA receptor antagonist (dizocilipine maleate, MK-801). The rats were observed for signs of capsaicin-induced mechanical and thermal hypersensitivity 15 min after capsaicin injection, and 20 min following i.t. drug administration. Results indicate there was a dose-dependent reduction in capsaicin-induced mechanical hypersensitivity for all mGlu receptor agents; with maximal increases in mechanical thresholds that were 7-fold for AIDA and APDC, 7.5-fold for L-AP4 and 5.6-fold for MPEP. However, only a weak reduction (often non-significant) in thermal hypersensitivity was observed with each of the mGlu receptor drugs; thermal latencies were maximally increased by 125% (AIDA), 0% (MPEP), 8% APDC and 205% (L-AP4). By contrast, the highest dose of MK-801 was able to significantly reduce both mechanical (maximal 6.67-fold increase in threshold) and thermal (maximal 3-fold increase in latencies) hyperalgesia. We conclude that mGlu receptors contribute to the development of mechanical allodynia, but not thermal hyperalgesia, following capsaicin injury; while iGluRs may contribute to both thermal and mechanical hypersensitivity.     

Accumulation, transformation and tissue distribution of domoic acid, the amnesic shellfish poisoning toxin, in the common cuttlefish, Sepia officinalis

Domoic acid (DA) is a phycotoxin produced by some diatoms, mainly from the Pseudo-nitzschia genus, and has been detected throughout the marine food web. Although DA has been frequently found in cephalopod prey such as crustaceans and fish, little is known about DA accumulation in these molluscs. This study presents the first data showing relevant concentrations of DA detected in the common cuttlefish, Sepia officinalis, which is one of the most studied cephalopod species in the world. Domoic acid was consistently found throughout 2003 and 2004 in the digestive gland of cuttlefish reaching concentrations of 241.7 microg DA g(-1). The highest DA values were detected during spring and summer months, periods when Pseudo-nitzschia occur in the plankton. In fact, Pseudo-nitzschia blooms preceded the highest DA concentrations in cuttlefish. Evaluation of DA tissue distribution showed elevated DA concentrations in the digestive gland and branchial hearts. Further, DA isomers comprised a relevant percentage of the toxin profile, indicating degradation and biotransformation of the toxin in the branchial hearts. The common cuttlefish, like other cephalopod species, plays a central position in the food web and might be a new DA vector to top predators like marine mammals. Human intoxications are not expected since DA was only seldom detected in the mantle and even then in very low levels (max 0.7 microg DA g(-1)). However, in some countries whole juvenile animals are consumed (i.e. without evisceration) and in this case they might represent a risk to human health. This study contributes to understanding the occurrence of phycotoxins in cephalopods and reveals a new member of the marine food web able to accumulate DA.     

Effect of cytokine genotypes on the hepatitis B virus-hepatocellular carcinoma association

BACKGROUND: In Southern Guangxi, China, chronic infection with the hepatitis B virus (HBV) acquired during the perinatal period from carrier mothers is a primary cause of hepatocellular carcinoma. However, only a minority of HBV carriers eventually develop hepatocellular carcinoma. The authors hypothesized that cytokine genotypes may be important codeterminants of the risk of HBV-related hepatocellular carcinoma. METHODS: The authors examined the correlation between polymorphisms in T-helper 1 (Th1) and Th2 cytokine genes among a group of 250 patients with incident hepatocellular carcinoma (cases) and a group of 250 hospital controls who were matched individually to the index case by age, gender, ethnicity, residence, and month of hospital admission in the city of Nanning, Guangxi, China. RESULTS: Relative to the putative high-activity genotypes, each individual low-activity genotype of interferon gamma, interleukin 12 (IL12), and IL18 was associated with a statistically nonsignificant increase (40-60%) in the risk of hepatocellular carcinoma. This risk increased with increasing numbers of low-activity Th1 genotypes after adjusting for potential confounders (2-sided P value for trend=0.04). Conversely, individual Th2 (IL4, IL10) low-activity genotypes were associated with a statistically nonsignificant reduced risk of hepatocellular carcinoma. This risk decreased with increasing number of low-activity Th2 genotypes after adjusting for potential confounders (2-sided P value for trend=0.01). Individuals who had the maximum number (i.e., 3) of low-activity Th1 genes and the minimum number (i.e., 0) of low-activity Th2 genes showed a relative risk of 20.0 (95% confidence interval, 1.7-235.0). CONCLUSIONS: Diminished cell-mediated immune response, which is controlled genetically, appeared to be an important risk determinant of HBV-related hepatocellular carcinogenesis.     

Antiemetic efficacy of the neurokinin-1 antagonist, aprepitant, plus a 5HT3 antagonist and a corticosteroid in patients receiving anthracyclines or cyclophosphamide in addition to high-dose cisplatin: analysis of combined data from two Phase III randomized clinical trials

BACKGROUND: The tendency of chemotherapeutic regimens to cause vomiting is dependent on the individual drugs in the regimen. The authors analyzed data combined from 2 Phase III trials to assess the effect of the neurokinin-1 (NK(1)) antagonist aprepitant combined with a 5HT(3) antagonist plus a corticosteroid in a subpopulation receiving > 1 emetogenic chemotherapeutic agent. METHODS: In the current study, 1043 cisplatin-naive patients (42% were women) receiving cisplatin-based (> or = 70 mg/m(2)) chemotherapy were assigned randomly to a control regimen (ondansetron [O] 32 mg intravenously and dexamethasone [D] 20 mg orally on Day 1; D 8 mg twice daily on Days 2-4) or an aprepitant (A) regimen (A 125 mg orally plus O 32 mg and D 12 mg on Day 1; A 80 mg and D 8 mg once daily on Days 2-3; and D 8 mg on Day 4). Randomization was stratified for use of concomitant chemotherapy and female gender. The primary end point was complete response (no vomiting and no rescue therapy) on Days 1-5 (0-120 hours). Data were analyzed by a modified intent-to-treat approach, and logistic regression was used to make treatment comparisons among patients receiving the most frequently coadministered emetogenic concomitant chemotherapy (Hesketh level > or = 3). RESULTS: Among the approximately 13% of patients (n = 81 for A; n = 80 for control) who received additional emetogenic chemotherapy (doxorubicin or cyclophosphamide), the aprepitant regimen provided a 33 percentage-point improvement in the complete response rate compared with the control regimen. Among the general population, the advantage with aprepitant was 20 percentage points. CONCLUSIONS: The current analysis of > 1000 patients from 2 large randomized trials showed that in the subpopulation at increased risk of chemotherapy-induced nausea and vomiting due to concomitant emetogenic chemotherapy, the addition of aprepitant to standard antiemetics improved protection to an even greater extent than in the general study population.     

Does a delay in external beam radiation therapy after tissue diagnosis affect outcome for men with prostate carcinoma?

BACKGROUND: Physicians involved in the care of men diagnosed with prostate carcinoma must assess the urgency of treatment. For those men who choose external beam radiation therapy (EBRT), the delay from the time of biopsy to treatment may be stressful. There are limited data on the consequences of radiation treatment delay. The purpose of the current study was to evaluate the effect of time to treatment (TTT) on outcomes. METHODS: The authors of the current study analyzed 1322 patients who were treated with EBRT alone. Overall survival (OS), cause specific survival (CSS), distant metastasis (DM), and freedom from biochemical failure (FFBF) were calculated. TTT was first analyzed at 4 intervals: < 3, 3-6, 6-9 and > 9 months, and at the median TTT. Cox multivariate analysis (MVA) was then performed with 2002 American Joint Commission on Cancer T-stage, Gleason score, prostate specific antigen (PSA), radiation dose, and TTT as covariates. RESULTS: There were no statistical differences in OS, CSS, DM, or FFBF among men whose EBRT began < 3, 3-6, 6-9, or > 9 months after diagnosis. This was also true at the median TTT of 3.1 months. A subgroup analysis was performed in which patients were stratified into low-, intermediate- and high-risk groups based on pretreatment PSA, Gleason score and AJCC T-stage. FFBF, and DM were calculated above and below the median TTT of 3.1 months. In this analysis, there was no statistically significant difference in FFBF or DM within the risk groups. CONCLUSIONS: Within the limits of the current study, data indicate that a treatment delay, even in high-risk patients, has little effect on clinical or biochemical outcome.     

Team Epi-Aid: graduate student assistance with urgent public health response

Team Epi-Aid provides graduate students with practical public health experience through participation in outbreak investigations and other applied projects with state and local health departments in North Carolina. It is an initiative of the North Carolina Center for Public Health Preparedness in the North Carolina Institute for Public Health at the University of North Carolina School of Public Health. The program allows state and local health departments access to volunteers and technical expertise from the university when they need assistance. It requires close collaboration with state and county health departments. Team Epi-Aid provides the opportunity for integrated learning with students and faculty within the departments of the School of Public Health, and through recent expansion, within the schools of Medicine and Pharmacy. Orientations are conducted each semester and formal training is provided as needed. Team Epi-Aid has been popular, with 58 active student participants contributing 1,465 hours of service during the initiative's first 21 months.     

Can we evaluate population screening strategies in UK general practice? A pilot randomised controlled trial comparing postal and opportunistic screening for genital chlamydial infection

STUDY OBJECTIVE: To assess whether opportunistic and postal screening strategies for Chlamydia trachomatis can be compared with usual care in a randomised trial in general practice. DESIGN: Feasibility study for a randomised controlled trial. SETTING: Three West of Scotland general medical practices: one rural, one urban/deprived, and one urban/affluent. PARTICIPANTS: 600 women aged 16-30 years, 200 from each of three participating practices selected at random from a sample of West of Scotland practices that had expressed interest in the study. The women could opt out of the study. Those who did not were randomly assigned to one of three groups: postal screening, opportunistic screening, or usual care. RESULTS: 38% (85 of 221) of the approached practices expressed interest in the study. Data were collected successfully from the three participating practices. There were considerable workload implications for staff. Altogether 124 of the 600 women opted out of the study. During the four month study period, 55% (81 of 146) of the control group attended their practice but none was offered screening. Some 59% (80 of 136) women in the opportunistic group attended their practice of whom 55% (44 of 80) were offered screening. Of those, 64% (28 of 44) accepted, representing 21% of the opportunistic group. Forty eight per cent (59 of 124) of the postal group returned samples. CONCLUSION: A randomised controlled trial comparing postal and opportunistic screening for chlamydial infection in general practice is feasible, although resource intensive. There may be problems with generalizing from screening trials in which patients may opt out from the offer of screening.