The impact of endoscopic ultrasound on the management and outcome of patients with oesophageal cancer: an update of a systematic review.

AIM: To provide an updated systematic review concerning the impact of endoscopic ultrasound (EUS) in the modern era of oesophageal cancer staging. MATERIALS AND METHODS: To update the previous systematic review, databases including MEDLINE and EMBASE were searched and studies published from 2005 onwards were selected. Studies reporting primary data in patients with oesophageal or gastro-oesophageal junction cancer who underwent radiological staging and treatment, regardless of intent, were included. The primary outcome was the reported change in management after EUS. Secondary outcomes were recurrence rate and overall survival. Two reviewers extracted data from included articles. This study was registered with PROSPERO (CRD42021231852). RESULTS: Eighteen studies with 11,836 patients were included comprising 2,805 patients (23.7%) who underwent EUS compared to 9,031 (76.3%) without EUS examination. Reported change of management varied widely from 0% to 56%. When used, EUS fine-needle aspiration precluded curative treatment in 37.5%-71.4%. Overall survival improvements ranged between 121 and 639 days following EUS intervention compared to patients without EUS. Smaller effect sizes were observed in a randomised controlled trial, compared to larger differences reported in observational studies. CONCLUSION: Current evidence for the effectiveness of EUS in oesophageal cancer pathways is conflicting and of limited quality. In particular, the extent to which EUS adds value to contemporary cross-sectional imaging techniques is unclear and requires formal re-evaluation.

Retinal stem cells in the adult mammalian eye.

The mature mammalian retina is thought to lack regenerative capacity. Here, we report the identification of a stem cell in the adult mouse eye, which represents a possible substrate for retinal regeneration. Single pigmented ciliary margin cells clonally proliferate in vitro to form sphere colonies of cells that can differentiate into retinal-specific cell types, including rod photoreceptors, bipolar neurons, and Müller glia. Adult retinal stem cells are localized to the pigmented ciliary margin and not to the central and peripheral retinal pigmented epithelium, indicating that these cells may be homologous to those found in the eye germinal zone of other nonmammalian vertebrates.

Potassium channels in hippocampal neurones are absent in a transgenic but not in a chemical model of Alzheimer's disease.

We have investigated using single channel patch-clamp methods potassium channel prevalence in hippocampal neurones from two animal models of AD. Experiments have been carried out on transgenic mice (Tg2576) carrying the Swedish mutation (K670N/M671L) and rats receiving ventricular infusions of okadaic acid. In cell-attached patches from hippocampal neurones from the Tg2576 and control littermate mice there were three principal unitary conductance - 22 pS, 111 pS and 178 pS. The two channels of intermediate and large conductance were voltage-dependent, highly active in cell-attached patches, activity decreasing markedly on hyperpolarisation. The large conductance channel was sensitive to TEA, iberiotoxin, was activated in excised inside-out patches by Ca 2+(i) and is the type I maxi-K+ channel. Significantly, there was a reduction in the prevalence of a TEA-sensitive 113 pS channel in neurones from TG2576 mice with a corresponding increase in prevalence of the maxi-K+ channel. There was no difference in the characteristics of maxi-K+ between patches in neurones from the transgenic and littermate controls. In the rat model single channel analysis was performed on hippocampal neurons from three groups of animals i.e. non-operated, and these receiving an infusion of vehicle or vehicle with okadaic acid. Three principal unitary conductances of around 18 pS, 118 pS and 185 pS were also observed in cell-attached recordings from these three groups. The intermediate and high conductance channels were blocked by TEA or 4-AP or 140 mM RbCl. There were no statistically significant differences in the channel prevalence or channel density between the control and test groups.

Cancer genetic risk assessment for individuals at risk of familial breast cancer.

BACKGROUND: The recognition of an inherited component to breast cancer has led to an increase in demand for information, reassurance, and genetic testing, resulting in the creation of genetics clinics for familial cancer. The first step for patients referred to a cancer genetic clinic is a risk assessment. OBJECTIVES: To evaluate the impact of cancer genetic risk assessment services on patients at risk of familial breast cancer. SEARCH STRATEGY: The specialised register maintained by the Cochrane Breast Cancer Group was searched. We also searched MEDLINE, EMBASE, CINAHL, PsycLIT, CENTRAL, DARE, ASSIA, Web of Science, SIGLE and LILACS. The searches covered the period 1985 to February 2005. We also hand-searched relevant journals. SELECTION CRITERIA: Trials looking at interventions for cancer genetic risk assessment delivery for familial breast cancer were considered for inclusion. Trials assessed outcomes such as understanding of risk, satisfaction and psychological well-being. Studies were excluded if they concerned cancers other than breast cancer or if participants were not at risk of breast cancer. Trials concerning the provision of information or education were also excluded as it was intended to review these separately. Participants could be individuals of any age or gender, with or without a known BRCA mutation, but without a previous history of breast cancer or any other serious illness. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. Additional information was sought from investigators as necessary. Due to the heterogeneity of both the interventions and outcomes, data were analysed descriptively. MAIN RESULTS: Fifty-eight papers were identified as relevant to the review, 54 of these were subsequently excluded. The three included trials (pertaining to five papers), provide data on 1251 participants and assessed the impact of cancer genetic risk assessment on outcomes including perceived risk, and psychological distress. This review suggests that cancer genetic risk assessment services help to reduce distress, improve the accuracy of the perceived risk of, and increase knowledge about, breast cancer and genetics. The health professional delivering the risk assessment does not appear to have a significant impact on these outcomes. AUTHORS' CONCLUSIONS: This review found favourable outcomes for patients' risk assessment for familial breast cancer. However, there were too few papers to make any significant conclusions about how best to deliver cancer genetic risk assessment services. Further research is needed assessing the best means of delivering cancer risk assessment, by different health professionals, in different ways and in alternative locations.

Cryotherapy for localised prostate cancer.

BACKGROUND: Prostate cancer is a common cancer in elderly men and in some will prove fatal. Standard treatments for localised disease include surgery ( radical prostatectomy), radiotherapy and active monitoring. New emerging therapies are being evaluated with the aim of reducing the complication rate associated with standard therapies, as well as developing an effective treatment. One such modality is cryotherapy, a procedure that introduces probes directly into the prostate tumour and kills the malignant cells by a freezing process. OBJECTIVES: This review aims to evaluate the relative clinical and economic benefits of cryotherapy compared to standard therapies for the primary treatment of localised prostate cancer. SEARCH STRATEGY: Our search strategy included an electronic search of MEDLINE from 1996 to December 2006, plus EMBASE (Excerpta Medica Database), the Cochrane library, ISI Science Citation Index, Database of Abstracts and Reviews of Effectiveness (DARE), and LILACS to identify all relevant published randomised trials of cryotherapy for localised prostate cancer. Cancerlit and HealthSTAR databases were searched to their final date. Handsearching of relevant journals was undertaken. SELECTION CRITERIA: Only published randomised trials comparing the effectiveness of cryotherapy with radical prostatectomy, radiotherapy or active monitoring for the primary treatment of men with localised prostate cancer were eligible for inclusion in this review. DATA COLLECTION AND ANALYSIS: Data were extracted from eligible studies, and included study design, participants, interventions and outcomes. Primary outcome measures were biochemical disease-free survival, disease-free survival and treatment-induced complications. Secondary outcomes included disease-specific survival, overall survival, quality-of-life outcome measures and economic impact measures. MAIN RESULTS: There were no randomised trials found comparing cryotherapy with other therapies for the primary treatment of localised prostate cancer. All studies identified were case series. To indicate the level of the available evidence, studies that evaluated cryotherapy as a primary therapy, using transrectal ultrasound guidance and urethral warming in at least 50 patients with localised prostate cancer, and a minimum of one year follow up, were reviewed. Eight case series were identified that complied with these criteria; two were retrospective. The patients recruited (n = 1483) had an age range from 41 to 84 years, stages T1 = 0 to 43%, T2 = 24 to 88%, T3 = 1 to 41%, and T4 = 0 to 14%. The mean preoperative PSA level ranged from 9.7 to 39 ng/mL, with Gleason scores < 7 and ranging from 6 to 37%. One additional study that compared cryotherapy (total cryotherapy and standard cryotherapy with urethral preservation) with radical prostatectomy was also identified and reviewed. In this study the success rates, defined as a post-treatment PSA of 0.2 ng/mL or less, were reported as 96% for total cryotherapy, 49% for standard cryotherapy and 73% for radical prostatectomy. Four studies did not monitor the temperature of the cyro-procedure and reported 17 to 28% of patients had a positive biopsy following cryotherapy with a mean PSA nadir of 0.55 to 1.75 ng/mL (median 0.4 to 1.85 ng/mL). The other four studies used thermocouples to monitor the temperature of the cryo-procedure and reported progression-free survival rates of 71 to 89% with 1.4 to 13% of patients having a positive biopsy post-cryotherapy. At 5 years, overall survival was reported as 89 to 92% in two studies, and disease-specific survival as 94% in one study. The major complications observed in all studies included impotence (47 to 100%), incontinence (1.3 to 19%), and urethral sloughing (3.9 to 85%), with less common complications of fistula (0 to 2%), bladder-neck obstruction (2 to 55%), stricture (2.2 to 17%) and pain (0.4 to 3.1%). Most patients were sent home the following day (range 1 to 4 days). AUTHORS' CONCLUSIONS: Cryotherapy offers a potential alternative to standard therapies for the primary treatment of localised prostate cancer. However, the poor quality of the available studies makes it difficult to determine the relative benefits of this modality. Randomised trials are needed to fully evaluate the full potential of cryotherapy in men with this disease. Patients selecting cryotherapy as their therapeutic option should be made fully aware of the reported efficacy, complications and the low-grade evidence from which these data are derived.

Palliative radiotherapy regimens for non-small cell lung cancer.

BACKGROUND: Palliative radiotherapy to the chest is often used in patients with lung cancer, but radiotherapy regimens are more often based on tradition than research results. OBJECTIVES: To discover the most effective and least toxic regimens of palliative radiotherapy for non-small cell lung cancer, and whether higher doses increase survival. SEARCH STRATEGY: The electronic databases MEDLINE, EMBASE, Cancerlit and the Cochrane Central Register of Controlled Trials, reference lists, handsearching of journals and conference proceedings, and discussion with experts were used to identify potentially eligible trials, published and unpublished. SELECTION CRITERIA: Randomised controlled clinical trials comparing different regimens of palliative radiotherapy in patients with non-small cell lung cancer. DATA COLLECTION AND ANALYSIS: Fourteen randomised trials were reviewed. There were important differences in the doses of radiotherapy investigated, the patient characteristics and the outcome measures. Because of this heterogeneity no meta-analysis was attempted. MAIN RESULTS: There is no strong evidence that any regimen gives greater palliation. Higher dose regimens give more acute toxicity, especially oesophagitis. There is evidence for a modest increase in survival (5% at 1 year and 3% at 2 years) in patients with better performance status (PS) given higher dose radiotherapy. Some regimens are associated with an increased risk of radiation myelitis. AUTHORS' CONCLUSIONS: The majority of patients should be treated with short courses of palliative radiotherapy, of 1 or 2 fractions. Care should be taken with the dose to the spinal cord. The use of high dose palliative regimens should be considered for and discussed with selected patients with good performance status. More research is needed into reducing the acute toxicity of large fraction regimens and into the role of radical compared to high dose palliative radiotherapy. In the future, large trials comparing different RT regimens may be difficult to set up because of the increasing use of systemic chemotherapy. Trials looking at how best to integrate these two modalities, particularly in good PS patients, need to be carried out.

Neo-adjuvant and adjuvant hormone therapy for localised and locally advanced prostate cancer.

BACKGROUND: Hormone therapy for early prostate cancer has demonstrated an improvement in clinical and pathological variables, but not always an improvement in overall survival. We performed a systematic review of both adjuvant and neo-adjuvant hormone therapy combined with surgery or radiotherapy in localised or locally advanced prostate cancer. OBJECTIVES: The objective of this review was to undertake a systematic review and, if possible, a meta-analysis of neo-adjuvant and adjuvant hormone therapy in localised or locally advanced prostate cancer. SEARCH STRATEGY: We searched MEDLINE (1966-2006), EMBASE, The Cochrane Library, Science Citation Index, LILACS, and SIGLE for relevant randomised trials. Handsearching of appropriate publications was also undertaken. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials of patients with localised or locally advanced prostate cancer, that is, stages T1-T4, any N, M0, comparing neo-adjuvant or adjuvant hormonal deprivation in combination with primary therapy (radical radiotherapy or radical prostatectomy) versus primary therapy alone were included in this review. DATA COLLECTION AND ANALYSIS: Data were extracted from eligible studies and assessed for quality, and included information on study design, participants, interventions, and outcomes. Comparable data were pooled together for meta-analysis with intention-to treat principle. MAIN RESULTS: Men with prostate cancer have different clinical outcomes based on their risk (T1-T2, T3-T4, PSA levels and Gleason score). However, the majority of studies included in this review did not report results by risk groups; therefore, it was not possible to perform sub-group analysis. Neo-adjuvant hormonal therapy prior to prostatectomy did not improve overall survival (OR 1.11, 95% CI 0.67 to 1.85, P = 0.69). However, there was a significant reduction in the positive surgical margin rate (OR 0.34, 95% CI 0.27 to 0.42, P < 0.00001) and a significant improvement in other pathological variables such as lymph node involvement, pathological staging and organ confined rates. There was a borderline significant reduction of disease recurrence rates (OR 0.74, 95% CI 0.55 to 1.0, P = 0.05), in favour of treatment. The use of longer duration of neo-adjuvant hormones, that is either 6 or 8 months prior to prostatectomy, was associated with a significant reduction in positive surgical margins (OR 0.56, 95% CI 0.39 to 0.80, P = 0.002). In one study, neo-adjuvant hormones prior to radiotherapy significantly improved overall survival for Gleason 2 to 6 patients; although, in two studies, there was no improvement in disease-specific survival (OR 0.99, 95% CI 0.75 to 1.32, P = 0.97). However, there was a significant improvement in both clinical disease-free survival (OR 1.86, 95% CI 1.93 to 2.40, P < 0.00001) and biochemical disease-free survival (OR 1.93, 95% CI 1.45 to 2.56, P < 0.00001). Adjuvant androgen deprivation following prostatectomy did not significantly improve overall survival at 5 years (OR 1.50, 95% CI 0.79 to 2.85, P = 0.2); although one study reported a significant disease-specific survival advantage with adjuvant therapy (P = 0.001). In addition, there was a significant improvement in disease-free survival at both 5 years (OR 3.73, 95%CI 2.30 to 6.03, P < 0.00001) and 10 years (OR 2.06, 95% CI 1.34 to 3.15, P = 0.0009). Adjuvant therapy following radiotherapy resulted in a significant overall survival gain apparent at 5 (OR 1.46, 95% CI 1.17 to 1.83, P = 0.0009) and 10 years (OR 1.44, 95% CI 1.13 to 1.84, P = 0.003); although there was significant heterogeneity (P = 0.09 and P = 0.07, respectively). There was also a significant improvement in disease-specific survival (OR 2.10, 95% CI 1.53 to 2.88, P = 0.00001) and disease-free survival (OR 2.53, 95% CI 2.05 to 3.12, P < 0.00001) at 5 years. AUTHORS' CONCLUSIONS: Hormone therapy combined with either prostatectomy or radiotherapy is associated with significant clinical benefits in patients with local or locally advanced prostate cancer. Significant local control may be achieved when given prior to prostatectomy or radiotherapy, which may improve patient's quality of life. When given adjuvant to these primary therapies, hormone therapy, not only provides a method for local control, but there is also evidence for a significant survival advantage. However, hormone therapy is associated with significant side effects, such as hot flushes and gynaecomastia, as well as cost implications. The decision to use hormone therapy should, therefore, be taken at a local level, between the patient, clinician and policy maker, taking into account the clinical benefits, toxicity and cost. More research is needed to guide the choice, the duration, and the schedule of hormonal deprivation therapy, and the impact of long-term hormone therapy with regard to toxicity and the patient's quality of life.

Dual-frequency proton spin relaxation measurements on tissues form normal and tumor-bearing mice.

Measurements of pulsed nuclear magnetic resonance relaxation times T1 and T2 were made at 2.7 MHz and 15 MHz on water protons in liver, kidney, spleen, muscle, and brain tissue from normal A.SW mice, and in the same tissues and tumors from A.SW mice developing MSWBS tumors (an ascites sarcoma) following dorsal sc implantation of tumor fragments. The measurement precision obtained from improved spectrometer design made it possible to show that T1 and T2 in all tissues except brain were increased by the presence of the tumor in the animal. The responses exhibited by T1 and T2 in liver and kidney were proportional to the size of the tumor. The smaller responses shown by T1 in spleen (15 MHz) and T1 and T2 in muscle (2.7 MHz) also showed a significant correlation with tumor size. The relaxation times for tumor (T1 at 2.7 MHz, T2 at 2.7 and 15 MHz) showed a significant negative correlation with tumor size: The times decreased as tumor size increased. The results were analyzed by use of the two-phase fast exchange model and were consistent with the effects expected if tissue water content increased and tumor water content decreased as tumor size increased. The analysis indicated that the effects arose primarily through changes in b, the fraction of water bound to fast exchange sites on the protein, with important modifications from changes in the correlation times Tc and Tm;Tr controlled the frequency that must be chosen for specific diagnostic applications.

Inhibition of CYP1A2 and CYP3A4 by oltipraz results in reduction of aflatoxin B1 metabolism in human hepatocytes in primary culture.

Dithiolethiones are thought to act as potent chemoprotective agents against aflatoxin B1 (AFB1)-induced hepatocarcinogenesis in the rat by inducing glutathione S-transferases (GSTs). To determine whether these antioxidants can be similarly effective in human beings, we have investigated metabolism of AFB1, in primary human hepatocytes with or without pretreatment by oltipraz (OPZ), a synthetic derivative of the natural 1,2-dithiole-3-thione. Aflatoxin M1 (AFM1), glutathione conjugates of AFB1 oxides (AFBSGs), and unchanged AFB1 were quantitated in cultures derived from eight human liver donors. Parenchymal cells obtained from the three GST M1-positive livers metabolized AFB1 to AFM1 and to AFBSGs derived from the isomeric exo-and endo-8,9-oxides, whereas no AFBSGs were formed in the GST M1-null cells. Pretreatment of the cells with 3-methylcholanthrene or rifampicin, inducers of CYP1A2 and CYP3A4, respectively, caused a significant increase in AFB1 metabolism. Although OPZ induced GST A2, and to a lesser extent GST A1 and GST M1, it decreased formation of AFM1 and AFBSG, which involves CYP1A2 and CYP3A4. Inhibition by OPZ of AFB1 metabolism by reducing CYP1A2 and CYP3A4 was also demonstrated by decreased activity of their monooxygenase activities toward ethoxyresorufin and nifedipine, respectively. The significant inhibition by OPZ of human recombinant yeast CYP1A2 and CYP3A4 was also shown. These results demonstrate that AFBSG can be formed by GST M1-positive human hepatocytes only, and suggest that chemoprotection with OPZ is due to an inhibition of activation of AFB1, in addition to a GST-dependent inactivation of the carcinogenic exo-epoxide.

Induction of muscle protein degradation and weight loss by a tumor product.

Splenocytes from mice bearing a cachexia-inducing tumor (MAC16) have been fused with mouse myeloma cells to produce hybridomas, which have been cloned to produce antibody reactive to a material which copurified with a lipid-mobilizing factor isolated from the same tumor. The monoclonal antibody has been used to investigate factors potentially involved in the development of cachexia. The major protein detectable by immunoprecipitation of a partially purified lipid-mobilizing factor was M(r) 69,000, whereas Western blotting showed two bands of M(r) 69,000 and M(r) 24,000. Although the monoclonal antibody did not neutralize lipid-mobilizing activity in an in vitro assay, it did neutralize a serum factor capable of protein degradation in isolated gastrocnemius muscle. Affinity purification of MAC16 tumor homogenates using the monoclonal antibody yielded two immunoreactive bands of M(r) 69,000 and M(r) 24,000, which were further fractionated on a hydrophobic column (C8). This material was capable of inducing tyrosine release from isolated gastrocnemius muscle, and the effect could be blocked with the monoclonal antibody. The two immunoreactive bands from the hydrophobic column were capable of inducing weight loss in mice, whereas nonimmunoreactive fractions had no effect on body weight. The M(r) 24,000 species had a unique amino acid sequence, whereas the M(r) 69,000 species gave the same sequence as the M(r) 24,000 material, together with that for albumin. The M(r) 24,000 species contained carbohydrate, and lectin blotting showed a strong reaction with wheat germ and Erythrina crystagalli agglutinins. This suggests that the material is a glycoprotein or proteoglycan that shows strong binding affinity for albumin, possibly through the carbohydrate residues.

Association between survival after treatment for breast cancer and glutathione S-transferase P1 Ile105Val polymorphism.

A glutathione S-transferase (GST) P1 polymorphism results in an amino acid substitution, Ile105Val; the Val-containing enzyme has reduced activity toward alkylating agents. Cancer patients with the variant enzyme may differ in removal of treatment agents and in outcomes of therapy. We evaluated survival according to GSTP1 genotype among women (n = 240) treated for breast cancer. Women with the low-activity Val/Val genotype had better survival. Compared with Ile/Ile, hazard ratios for overall survival were 0.8 (95% confidence interval, 0.5-1.3) for Ile/Val and 0.3 (95% confidence interval, 0.1-1.0) for Val/Val (P for trend = 0.04). Inherited metabolic variability may influence treatment outcomes.

Polymorphisms in glutathione S-transferases (GSTM1 and GSTT1) and survival after treatment for breast cancer.

The response to treatment for breast cancer is likely predicted by a number of disease and tumor tissue characteristics, many of which are under active investigation. One area that has received little attention is that of endogenous capabilities to respond to reactive oxygen species and subsequent byproducts resulting from radiation therapy and a number of chemotherapeutic agents, preventing cytotoxicity toward tumor cells. The glutathione S-transferases are key conjugating enzymes in this response, and GSTM1 and GSTT1 have deletion polymorphisms that result in no enzyme activity. In this retrospective study, we evaluated the role of GSTM1- and GSTT1-null genotypes on disease-free and overall survival among 251 women who received treatment for incident, primary breast cancer. Women were identified through Tumor Registry records and normal archived tissue retrieved for genotyping. Adjusting for age, race, and stage at diagnosis, women with null genotypes for GSTM1 and GSTT1 had reduced hazard of death [adjusted hazard ratio (HR), 0.59; 95% confidence interval (CI), 0.36-0.97; and HR, 0.51; CI, 0.29-0.90, respectively] in relation to those with alleles present. Furthermore, women who were null for both GSTM1 and GSTT1 had one-third the hazard of death of those with alleles for both genes present (adjusted HR, 0.28; 95% CI, 0.11-0.70). Similar relationships were noted for risk of recurrence. These data indicate that interindividual differences in activity of enzymes that prevent therapy-generated reactive oxidant damage may have an important impact on disease recurrence and overall survival.

Quantitative analysis of interindividual variation of glutathione S-transferase expression in human pancreas and the ambiguity of correlating genotype with phenotype.

Analysis of glutathione S-transferases (GSTs) of the alpha, mu, and pi classes by reverse-phase high-performance liquid chromatography and electrospray-ionization mass spectrometry in 43 samples of normal human pancreas demonstrated a wide variation in expression of subunits P1, A1, A2, A4, M1, M2, and M3 and the presence of a novel form designated GST "A5." GSTA2 consisted of three forms that were differentially expressed between individuals in a manner consistent with allelic polymorphism at the hGSTA2 locus. Expression, in terms of microg GST subunit/mg cytosolic protein, varied by 6-15-fold for subunits P1, A2, and M3 and 17-30-fold in the case of GSTs A1 and M2. Less consistently expressed were GSTs M1a, M1b, A4, and A5. Among these, GSTM1 expression (excluding M1-null samples) varied 12-fold between samples, whereas GST A4 and A5 expression varied approximately 50-100-fold between samples, well beyond the range of other subunits, suggesting that their expression is highly inducible. Linear correlations (P < 0.001-0.003) existed between levels of the most consistently expressed GST, GSTP1, and total GSTs, GSTA2 and M3, and in GSTM1-positive samples, between GSTM1, M3, and P1. The correlation between GST subunits P1 and M3 was bimodal according to M1 genotype, reflecting the presence of the regulatory element in hGSTM3*B that is linked with the hGSTM1*A genotype. It is concluded that although a degree of regulation of expression of GSTs occurs in human pancreas, the variability of phenotype is high and might obscure the effects of genetic polymorphisms on individual cancer susceptibility. Interindividual variation of GST expression is, therefore, a factor that should be taken account of in epidemiological studies.

Injectable hydrogel promotes early survival of induced pluripotent stem cell-derived oligodendrocytes and attenuates longterm teratoma formation in a spinal cord injury model.

Transplantation of pluripotent stem cells and their differentiated progeny has the potential to preserve or regenerate functional pathways and improve function after central nervous system injury. However, their utility has been hampered by poor survival and the potential to form tumors. Peptide-modified biomaterials influence cell adhesion, survival and differentiation in vitro, but their effectiveness in vivo remains uncertain. We synthesized a peptide-modified, minimally invasive, injectable hydrogel comprised of hyaluronan and methylcellulose to enhance the survival and differentiation of human induced pluripotent stem cell-derived oligodendrocyte progenitor cells. Cells were transplanted subacutely after a moderate clip compression rat spinal cord injury. The hydrogel, modified with the RGD peptide and platelet-derived growth factor (PDGF-A), promoted early survival and integration of grafted cells. However, prolific teratoma formation was evident when cells were transplanted in media at longer survival times, indicating that either this cell line or the way in which it was cultured is unsuitable for human use. Interestingly, teratoma formation was attenuated when cells were transplanted in the hydrogel, where most cells differentiated to a glial phenotype. Thus, this hydrogel promoted cell survival and integration, and attenuated teratoma formation by promoting cell differentiation.

Prophylactic cranial irradiation for preventing brain metastases in patients undergoing radical treatment for non-small cell lung cancer.

BACKGROUND: In non-small cell lung cancer (NSCLC), there is a relatively high incidence of brain metastases following radical treatment. At present, the role of prophylactic cranial irradiation (PCI) in this group of patients is not clear. OBJECTIVES: To investigate whether PCI has a role in the management of patients with NSCLC treated with radical intent. SEARCH STRATEGY: The electronic databases MEDLINE, EMBASE and Cancerlit, along with handsearching of journals, relevant books, and review articles used to identify potentially eligible trials. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing PCI with no PCI in NSCLC patients treated with radical intent. DATA COLLECTION AND ANALYSIS: Four RCTs were reviewed. Due to the small patient numbers, and variations in radiotherapy (RT) dose, no meta-analysis was attempted. MAIN RESULTS: PCI may reduce the incidence of brain metastases, but there is no evidence of a survival benefit. There is no evidence that any regimen is superior, and the effect of PCI on quality of life (QOL) is not known. AUTHORS' CONCLUSIONS: There is insufficient evidence to support the use of PCI in clinical practice. Where possible, patients should be offered entry into a clinical trial.

Effect of polymorphism in the human glutathione S-transferase A1 promoter on hepatic GSTA1 and GSTA2 expression.

The patterns of expression of glutathione S-transferases A1 and A2 in human liver (hGSTA1 and hGSTA2, respectively) are highly variable, notably in the ratio of hGSTA1/hGSTA2. We investigated if this variation had a genetic basis by sequencing the proximal promoters (-721 to -1 nucleotides) of hGSTA1 and hGSTA2, using 55 samples of human liver that exemplified the variability of hGSTA1 and hGSTA2 expression. Variants were found in the hGSTA1 gene: -631T or G, -567T, -69C, -52G, designated as hGSTA1*A; and -631G, -567G, -69T, -52A, designated as hGSTA1*B. Genotyping for the substitution -69C > T by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), showed that the polymorphism was widespread in Caucasians, African-Americans and Hispanics, and that it appeared to conform to allelic variation. Constructs consisting of the proximal promoters of hGSTA1*A, hGSTA1*B or hGSTA2, with luciferase as a reporter gene, showed differential expression when transfected into HepG2 cells: hGSTA1*A approximately hGSTA2 > hGSTA1*B. Similarly, mean levels of hGSTA1 protein expression in liver cytosols decreased significantly according to genotype: hGSTA1*A > hGSTA1-heterozygous > hGSTA1*B. Conversely, mean hGSTA2 expression increased according to the same order of hGSTA1 genotype. Consequently, the ratio of GSTA1/GSTA2 was highly hGSTA1 allele-specific. Because the polymorphism in hGSTA1 correlates with hGSTA1 and hGSTA2 expression in liver, and hGSTA1-1 and hGSTA2-2 exhibit differential catalysis of the detoxification of carcinogen metabolites and chemotherapeutics, the polymorphism is expected to be of significance for individual risk of cancer or individual response to chemotherapeutic agents.

Thymine hydroperoxide, a substrate for rat Se-dependent glutathione peroxidase and glutathione transferase isoenzymes.

The thymine hydroperoxide, 5-hydroperoxymethyluracil, is a substrate for Se-dependent glutathione (GSH) peroxidase and the Se-independent GSH peroxidase activity associated with the GSH transferase fraction. These enzymes may contribute to repair mechanisms for damage caused by oxygen radicals. GSH transferases 1-1, 2-2, 3-3, 4-4, 6-6, and 7-7 [(1984) Biochem. Pharmacol. 33, 2539-2540] are shown to differ considerably in their ability to utilize this substrate. For example, high activity is found in GSH transferase 6-6 which is the major isoenzyme in spermatogenic tubules where DNA synthesis is so active and faithful DNA replication so important. The activity of the purified GSH transferase isoenzymes towards 5-hydroperoxymethyluracil is comparable with their activity towards other endogenous substrates related to cellular peroxidation such as linoleate hydroperoxide and 4-hydroxynon-2-enal or biologically important xenobiotic metabolites such as benzo(a)pyrene-7,8-diol-9,10-oxide.

Kinetics and equilibria of S-nitrosothiol-thiol exchange between glutathione, cysteine, penicillamines and serum albumin.

The kinetics and equilibria of S-nitrosothiol-thiol (SNO-SH) exchange reactions were determined using differential optical absorption. At pH 7.4 and 37 degrees C, k2 values ranged from 0.9 M-1.s-1 for the reaction between S-nitroso-glutathione (GSNO) and N-acetyl-penicillamine, and up to 279 M-1.s-1 for the exchange between S-nitroso-penicillamine (penSNO) and GSH. SNO-SH exchange involving GSH/GSNO and cysteine/cySNO was relatively rapid, k2 approx. 80 M-1.s-1 with an equilibrium constant slightly in favour of GSNO. GSNO was strongly favoured in equilibrium with penSNO, keq 0.0039. In the case of SNO-SH exchange between S-nitroso human serum albumin (albSNO) and GSH or cysteine k2 values were 3.2 and 9.1 M-1.s-1, respectively. The results show that the initial rate of SNO-SH exchange between physiological albSNO (7 microM) and venous plasma levels of GSH and cysteine is very slow, < 1%/min. On the other hand, if a nitrosothiol such as cySNO were to enter a cell, it would be rapidly converted to GSNO (43%/s).

Glutathione transferases in primary rat hepatomas: the isolation of a form with GSH peroxidase activity.

A previously uncharacterized glutathione (GSH) transferase which is not apparent in normal liver, accounts for at least 25% of the soluble GSH transferase content of primary hepatomas induced by feeding N,N-dimethyl-4-aminoazobenzene. This enzyme is readily isolated, has an isoelectric point of 6.8, is composed of two identical subunits of apparent Mr 26000 and has GSH transferase activity towards a number of substrates including benzo(a)pyrene-7,8-diol-9,10-oxide. It is unusual in that it has GSH peroxidase activity towards fatty acid hydroperoxides but not towards the model substrates, cumene hydroperoxide and t-butyl hydroperoxide. It has been shown by tryptic peptide analysis to be distinct from GSH transferases composed of subunits 1, 2, 3, 4 or 6 and has been designated GSH transferase 7-7.

Isolation of cDNA clones encoding the human Sm B/B' auto-immune antigen and specifically reacting with human anti-Sm auto-immune sera.

A cDNA clone for the human SmB and B' auto-immune antigens has been isolated by antibody screening of a cDNA expression library. The cDNA clone hybridises with two distinct mRNAs, one of which is expressed in a tissue-specific manner. A fusion protein expressed from the cDNA clone was recognised by a number of sera from systemic lupus erythematosus (SLE) patients containing anti-Sm antibodies but not by sera reactive with other auto-immune antigens. The potential use of this clone in a diagnostic assay for SLE and in elucidating the processes regulating the expression of SmB and B' is discussed.