John Greenman

Microfluidic perfusion system for maintaining viable heart tissue with real-time electrochemical monitoring of reactive oxygen species

A microfluidic device has been developed to maintain viable heart tissue samples in a biomimetic microenvironment. This device allows rat or human heart tissue to be studied under pseudo in vivo conditions. Effluent levels of lactate dehydrogenase and hydrogen peroxide were used as markers of damaged tissue in combination with in situ electrochemical measurement of the release of reactive oxygen species (ROS). The parameters for perfusion were optimized to maintain biopsies of rat right ventricular or human right atrial tissue viable for up to 5 and 3.5 hours, respectively. Electrochemical assessment of the oxidation current of total ROS, employing cyclic voltammetry, gave results in real-time that were in good agreement to biochemical assessment using conventional, off-chip, commercial assays. This proof-of-principle, integrated microfluidic device, may be exploited in providing a platform technology for future cardiac research, offering an alternative approach for investigating heart pathophysiology and facilitating the development of new therapeutic strategies.

Serum IL10 and circulating CD4+CD25high regulatory T cell numbers as predictors of clinical outcome and survival in patients with head and neck squamous cell carcinoma

Patients with head and neck squamous cell carcinoma (HNSCC) commonly have an imbalance in T helper (Th)1/Th2‐type cytokines and elevated levels of CD4+CD25high regulatory T cells (Treg). Here, we investigated the association of circulating interleukin (IL)10, IL12, and Treg‐cells with clinical outcome in patients with HNSCC.

Unraveling the Chromosomal Aberrations of Head and Neck Squamous Cell Carcinoma: A Review

Information from the genetic analysis of head and neck cancer has grown enormously in the last 20 years. The advent of high-resolution genetic analysis techniques such as microarray technology will further expand this field in the future. Here we review the data on chromosomal aberrations of head and neck squamous cell carcinoma, focusing on the data generated by comparative genomic hybridization analysis, and suggest how such findings will be taken forward over the next decade. With the search engine PUBMED, the key words “comparative genomic hybridisation,” “head and neck,” “oral,” “hypopharyngeal,” “laryngeal,” and “squamous cell carcinoma” were used. Publications unavailable in English were excluded.

COX-2 specific inhibitors enhance the cytotoxic effects of pemetrexed in mesothelioma cell lines.

BACKGROUNDnAlthough malignant pleural mesothelioma is a rare tumour, its incidence is increasing. The prognosis remains very poor with an average survival of 10 months from diagnosis. The choice of chemotherapy regimens for mesothelioma patients is limited and new approaches are required. COX-2 inhibition induces apoptosis in a variety of tumour cell lines. The cytotoxic effect of conventional drugs may be enhanced by the addition of a COX-2 inhibitor. In order to identify possible new therapeutic approaches we aimed to determine whether the addition of COX-2 inhibitors would enhance the cytotoxic effect of chemotherapeutic agents in mesothelioma cell lines.nnnMATERIALS AND METHODSnThree mesothelioma cell lines MSTO-211H, NCI-H2052 and NCI-H2452 were utilised. Using the COX-2 positive A549 lung cancer cell line as control, all cell lines were assayed using an MTT assay with non-specific COX-2 inhibitors (sulindac and flurbiprofen), specific COX-2 inhibitors (DuP-697 and NS-398), and chemotherapeutic agents (cisplatin, vinorelbine and pemetrexed).nnnRESULTSnAll cell lines exhibited COX-2 expression by western blotting using two antibodies. The addition of either DuP-697 or NS-398 increased the sensitivity to pemetrexed in all cell lines.nnnCONCLUSIONnThese findings suggest that the design of novel pemetrexed-containing combination regimens with increased cytotoxicity may be feasible.

Mismatch repair, p53 and chromosomal aberrations in primary colorectal carcinomas.

Colorectal carcinoma progresses via at least two genetic pathways. Microsatellite instability, due to defective mismatch repair genes, characterizes one pathway and gross chromosomal instability another. The involvement of p53 and mismatch repair gene abnormalities within these pathways has not been fully explored. We aimed to investigate the relationships of p53 and mismatch repair gene defects on gross chromosomal aberrations detected by comparative genomic hybridization in 49 colorectal carcinomas. Tumours demonstrating loss of expression for hMLH1 or hMSH2 proteins demonstrated a highly significant attenuation in the number of gross chromosomal aberrations (pu200a=u200a0.007) and were less likely to show p53 overexpression (pu200a=u200a0.02). Within the mismatch repair normal tumours, p53 status did not affect the total number of chromosomal aberrations but p53 overexpression was significantly associated with a higher frequency of amplifications at 8q22-ter and at 13q21-22. Colorectal cancer demonstrates distinct molecular phenotypes and should be sub-classified accordingly.

Implication of the BRCA2 and Putative “BRCA3” Genes in Dukes’ Stage C, Replication Error–Negative Colon Cancer

BackgroundAlthough BRCA genes have been implicated in certain tumors, particularly breast tumors, their role in colon tumorigenesis has not been fully explored. We aimed to investigate the association of the BRCA2 and putative “BRCA3” genes in a homogeneous series of right-sided colon cancer specimens.MethodsTwenty-three Dukes’ stage C, replication error–negative carcinomas were selected from patients with right-sided colon cancer. After histological examination and microdissection, DNA was extracted from normal colon and carcinoma from each patient. Five microsatellite markers spanning the region of BRCA2 and BRCA3 on chromosome 13 (D13S218, D13S219, D13S165, D13S156, and D13S160) and two markers intragenic to BRCA2 and BRCA3 (D13S171 and D13S1308, respectively) were used. Polymerase chain reaction products were analyzed by using a fluorescent allele imbalance assay.ResultsMarkers demonstrating the highest allelic imbalance were D13S1308 (53%), D13S171 (33%), and D13S160 (37%).ConclusionsThe intragenic markers D13S1308 (BRCA3) and D13S171 (BRCA2) on chromosome 13 demonstrated a high frequency of allelic imbalance in primary colon carcinoma. This suggests an involvement of BRCA2 and putative BRCA3 in colon tumorigenesis in right-sided, replication error–negative, Dukes’ stage C cancers. Further studies are needed to confirm the precise role of these genes, and any prognostic significance, in colon cancer.

Assessment of dendritic cell number and radiosensitivity in laryngeal tumours

Objectives:u2002 Radiotherapy is one of the principal treatment modalities for many types of head and neck tumour; what effects the dendritic cell (DC) population may have on treatment outcome have not been critically evaluated in laryngeal cancer.