Development and validation of a fully automated laboratory-developed test for detection of HSV-1/2 and VZV in clinical samples run on the Panther Fusion® system

The purpose of this study was to develop a laboratory developed test (LDT) for HSV1/2 and VZV to run on fully automated Hologic Panther Fusion® System. The Panther Fusion System is a fully automated walkaway system, providing end-to-end workflow from sample input to DNA/RNA extraction, amplification, automated analysis, and reporting to a laboratory information system (LIS). The LDT was developed and validated on 230 clinical and 20 reference samples (n = 250) and compared to a commercially available kit. Assessment of the analytical and diagnostic performances of the LDT revealed >98% accuracy, sensitivity, and specificity, which is consistent with or better than many of the commercial or laboratory-developed tests available. The advantage of this LDT is that it is designed to perform a single-run full female health screening in parallel with 4 commercially available Hologic kits for Chlamydia trachomatis/Neisseria gonorrhea (CT/NG), Trichomonas vaginalis (TV), Mycoplasma genitalium (MG), and bacterial vaginosis (BV).

Identification of mutagenic and endocrine disrupting compounds in surface water and wastewater treatment plant effluents using high-resolution effect-directed analysis

Effect-directed analysis (EDA) has shown its added value for the detection and identification of compounds with varying toxicological properties in water quality research. However, for routine toxicity assessment of multiple toxicological endpoints, current EDA is considered labor intensive and time consuming. To achieve faster EDA and identification, a high-throughput (HT) EDA platform, coupling a downscaled luminescent Ames and cell-based reporter gene assays with a high-resolution fraction collector and UPLC-QTOF MS, was developed. The applicability of the HT-EDA platform in the analysis of aquatic samples was demonstrated by analysis of extracts from WWTP influent, effluent and surface water. Downscaled assays allowed detection of mutagenicity and androgen, estrogen and glucocorticoid agonism following high-resolution fractionation in 228 fractions. From 8 masses tentatively identified through non-target analysis, 2 masses were further investigated and chemically and biologically confirmed as the mutagen 1,2,3-benzotriazole and the androgen androstenedione. The compatibility of the high-throughput EDA platform with analysis of water samples and the incorporation of mutagenic and endocrine disruption endpoints allow for future application in routine monitoring in drinking water quality control and improved identification of (emerging) mutagens and endocrine disruptors.

Compound Identification Using Liquid Chromatography and High-Resolution Noncontact Fraction Collection with a Solenoid Valve

We describe the development of a high-resolution, noncontact fraction collector for liquid chromatography (LC) separations, allowing high-resolution fractionation in high-density well plates. The device is based on a low-dead-volume solenoid valve operated at 1–30 Hz for accurate collection of fractions of equal volume. The solenoid valve was implemented in a modified autosampler resulting in the so-called FractioMate fractionator. The influence of the solenoid supply voltage on solvent release was determined and the effect of the frequency, flow rate, and mobile phase composition was studied. For this purpose, droplet release was visually assessed for a wide range of frequencies and flow rates, followed by quantitative evaluation of a selection of promising settings for highly accurate, repeatable, and stable fraction collection. The potential of the new fraction collector for LC-based bioactivity screening was demonstrated by fractionating the LC eluent of a mixture of estrogenic and androgenic compounds, and a surface water sample (blank and spiked with bioactives) combining mass spectrometric detection and two reporter gene assays for bioactivity detection of the fractions. Additionally, a mixture of two compounds was repeatedly LC separated and fractionated to assess the feasibility of the system for analyte isolation followed by nuclear magnetic resonance analysis.

Time-Integrative Passive sampling combined with TOxicity Profiling (TIPTOP): an effect-based strategy for cost-effective chemical water quality assessment

This study aimed at demonstrating that effect-based monitoring with passive sampling followed by toxicity profiling is more protective and cost-effective than the current chemical water quality assessment strategy consisting of compound-by-compound chemical analysis of selected substances in grab samples. Passive samplers were deployed in the Dutch river delta and in WWTP effluents. Their extracts were tested in a battery of bioassays and chemically analyzed to obtain toxicity and chemical profiles, respectively. Chemical concentrations in water were retrieved from publicly available databases. Seven different strategies were used to interpret the chemical and toxicity profiles in terms of ecological risk. They all indicated that the river sampling locations were relatively clean. Chemical-based monitoring resulted for many substances in measurements below detection limit and could only explain <20% of the observed in vitro toxicity. Effect-based monitoring yielded more informative conclusions as it allowed for ranking the sampling sites and for estimating a margin-of-exposure towards chronic effect ranges. Effect-based monitoring was also cheaper and more cost-effective (i.e. yielding more information per euro spent). Based on its identified strengths, weaknesses, opportunities, and threats (SWOT), a future strategy for effect-based monitoring has been proposed.

High-Throughput Effect-Directed Analysis Using Downscaled in Vitro Reporter Gene Assays To Identify Endocrine Disruptors in Surface Water

Effect-directed analysis (EDA) is a commonly used approach for effect-based identification of endocrine disruptive chemicals in complex (environmental) mixtures. However, for routine toxicity assessment of, for example, water samples, current EDA approaches are considered time-consuming and laborious. We achieved faster EDA and identification by downscaling of sensitive cell-based hormone reporter gene assays and increasing fractionation resolution to allow testing of smaller fractions with reduced complexity. The high-resolution EDA approach is demonstrated by analysis of four environmental passive sampler extracts. Downscaling of the assays to a 384-well format allowed analysis of 64 fractions in triplicate (or 192 fractions without technical replicates) without affecting sensitivity compared to the standard 96-well format. Through a parallel exposure method, agonistic and antagonistic androgen and estrogen receptor activity could be measured in a single experiment following a single fractionation. From 16 selected candidate compounds, identified through nontargeted analysis, 13 could be confirmed chemically and 10 were found to be biologically active, of which the most potent nonsteroidal estrogens were identified as oxybenzone and piperine. The increased fractionation resolution and the higher throughput that downscaling provides allow for future application in routine high-resolution screening of large numbers of samples in order to accelerate identification of (emerging) endocrine disruptors.

The Arabidopsis GORK K+-channel is phosphorylated by calcium-dependent protein kinase 21 (CPK21), which in turn is activated by 14-3-3 proteins

Potassium (K⁺) is a vital ion for many processes in the plant and fine-tuned ion channels control the K⁺-fluxes across the plasma membrane. GORK is an outward-rectifying K⁺-channel with important functions in stomatal closure and in root K⁺-homeostasis. In this study, post-translational modification of the Arabidopsis GORK ion channel and its regulation by 14-3-3 proteins was investigated. To investigate the possible interaction between GORK and 14-3-3s an in vivo pull-down from an Arabidopsis protein extract with recombinant GORK C-terminus (GORK-C) indeed identified endogenous 14-3-3s (LAMBDA, CHI, NU) as binding partners in a phosphorylation dependent manner. However, a direct interaction between 14-3-3's and GORK-C could not be demonstrated. Since the pull-down of 14-3-3s was phosphorylation dependent, we determined GORK-C as substrate for CPK21 phosphorylation and identified three CPK21 phospho-sites in the GORK protein (T³⁴⁴, S⁵¹⁸ and S⁶⁴⁹). Moreover, interaction of 14-3-3 to CPK21 strongly stimulates its kinase activity; an effect that can result in increased GORK phosphorylation and change in activity. Using the non-invasive vibrating probe technique, we measured the predominantly GORK mediated salt induced K⁺-efflux from wild-type, gork, cpk21, aha2 and 14-3-3 mutant roots. The mutants cpk21 and aha2 did not show statistical significant differences compared to WT. However, two (out of six) 14-3-3 isoforms, CHI and PHI, have a clear function in the salt induced K⁺-efflux. In conclusion, our results show that GORK can be phosphorylated by CPK21 and suggest that 14-3-3 proteins control GORK activity through binding with and activation of CPK21.

Bioassay battery interlaboratory investigation of emerging contaminants in spiked water extracts - Towards the implementation of bioanalytical monitoring tools in water quality assessment and monitoring

Bioassays are particularly useful tools to link the chemical and ecological assessments in water quality monitoring. Different methods cover a broad range of toxicity mechanisms in diverse organisms, and account for risks posed by non-target compounds and mixtures. Many tests are already applied in chemical and waste assessments, and stakeholders from the science-police interface have recommended their integration in regulatory water quality monitoring. Still, there is a need to address bioassay suitability to evaluate water samples containing emerging pollutants, which are a current priority in water quality monitoring. The presented interlaboratory study (ILS) verified whether a battery of miniaturized bioassays, conducted in 11 different laboratories following their own protocols, would produce comparable results when applied to evaluate blinded samples consisting of a pristine water extract spiked with four emerging pollutants as single chemicals or mixtures, i.e. triclosan, acridine, 17α-ethinylestradiol (EE2) and 3-nitrobenzanthrone (3-NBA). Assays evaluated effects on aquatic organisms from three different trophic levels (algae, daphnids, zebrafish embryos) and mechanism-specific effects using in vitro estrogenicity (ER-Luc, YES) and mutagenicity (Ames fluctuation) assays. The test battery presented complementary sensitivity and specificity to evaluate the different blinded water extract spikes. Aquatic organisms differed in terms of sensitivity to triclosan (algae > daphnids > fish) and acridine (fish > daphnids > algae) spikes, confirming the complementary role of the three taxa for water quality assessment. Estrogenicity and mutagenicity assays identified with high precision the respective mechanism-specific effects of spikes even when non-specific toxicity occurred in mixture. For estrogenicity, although differences were observed between assays and models, EE2 spike relative induction EC₅₀ values were comparable to the literature, and E2/EE2 equivalency factors reliably reflected the sample content. In the Ames, strong revertant induction occurred following 3-NBA spike incubation with the TA98 strain, which was of lower magnitude after metabolic transformation and when compared to TA100. Differences in experimental protocols, model organisms, and data analysis can be sources of variation, indicating that respective harmonized standard procedures should be followed when implementing bioassays in water monitoring. Together with other ongoing activities for the validation of a basic bioassay battery, the present study is an important step towards the implementation of bioanalytical monitoring tools in water quality assessment and monitoring.

Vascular fingerprint and vascular damage markers associated with vascular events in testicular cancer patients during and after chemotherapy

BACKGROUND

Metastatic testicular cancer (TC) can be cured with bleomycin, etoposide and cisplatin (BEP) chemotherapy. This comes at the price of an increased cardiovascular disease risk, not only years afterwards, but also during and shortly after chemotherapy. To prevent cardiovascular events, high-risk patients should be identified. The aim of this study was to assess BEP-chemotherapy induced vascular damage and to find risk factors for early vascular events.

PATIENTS AND METHODS

A prospective cohort study was performed in (B)EP treated TC patients. Development of venous and arterial vascular events was assessed. Vascular damage markers (von Willebrand factor [vWF], coagulation factor VIII [FVIII], intima media thickness [IMT]) and cardiovascular risk factors were assessed before and until 1 year after chemotherapy. Before start of chemotherapy a vascular fingerprint was estimated. Presence of ≥3 risk factors was defined as high-risk vascular fingerprint: body mass index >25 kg/m(2), current smoking, blood pressure >140/90 mm Hg, total cholesterol >5.1 and/or low-density lipoprotein >2.5 mmol/L or glucose ≥7 mmol/L.

RESULTS

Seventy-three patients were included. Eight (11%) developed vascular events (four arterial events, four pulmonary embolisms). vWF and FVIII increased during chemotherapy, especially in patients with vascular events. Sixteen patients (22%) had a high-risk vascular fingerprint before start of chemotherapy. These patients had arterial events more often (3/16 [19%] versus 1/57 [2%]; p = 0.031) and higher vWF levels and IMT.

CONCLUSIONS

Endothelial activation and upregulation of procoagulant activity seem important mechanisms involved in early (B)EP-chemotherapy-induced vascular events. Before chemotherapy, a quarter already had cardiovascular risk factors. A vascular fingerprint could identify patients at risk for arterial events. This vascular fingerprint, when validated, can be used as a tool to select patients who may benefit from preventive strategies.

Long-term exposure to circulating platinum is associated with late effects of treatment in testicular cancer survivors

Cisplatin is an essential part of testicular cancer treatment. We investigated whether long-term exposure to circulating platinum (Pt) plays a role in the development of late effects in survivors. We assessed Pt decay in samples collected 1–13 years after chemotherapy. Renal function is a strong determinant of exposure to Pt. Higher exposure to Pt is associated with an increased prevalence of adverse effects hypogonadism and hypertension.

Background

The success of cisplatin-based (Platinol, Bristol-Myers Squibb Company, New York, NY, USA) chemotherapy for testicular cancer comes at the price of long-term and late effects related to healthy tissue damage. We assessed and modelled serum platinum (Pt) decay after chemotherapy and determined relationships between long-term circulating Pt levels and known late effects.

Patients and methods

In 99 testicular cancer survivors, treated with cisplatin-based chemotherapy, serum and 24-h urine samples were collected during follow-up (1–13 years after treatment). To build a population pharmacokinetic model, measured Pt data were simultaneously analysed, together with cisplatin dose, age, weight and height using the NONMEM software. Based on this model, area under the curve between 1 and 3 years after treatment (Pt AUC_{1–3 years}) was calculated for each patient. Predicted long-term Pt exposure was related to renal function and to late effects of treatment assessed median 9 (3–15) years after chemotherapy.

Results

Decay of Pt was best described by a two-compartment model. Mean terminal T_1/2 was 3.7 (range 2.5–5.2) years. Pt AUC_{1–3 years} correlated with cumulative cisplatin dose, and creatinine clearance before and 1 year after treatment. Patients with paraesthesia had higher Pt AUC_{1–3 years} (30.9 versus 27.0 µg/l month) compared with those without paraesthesia (P = 0.021). Patients with hypogonadism, elevated LDL-cholesterol levels or hypertension also had higher Pt AUC_{1–3 years}.

Conclusions

Renal function before and after cisplatin treatment is an important determinant of long-term Pt exposure. Known long-term effects of testicular cancer treatment, such as paraesthesia, hypogonadism, hypercholesterolaemia and hypertension, are associated with long-term circulating Pt exposure.

Regulation of TRAIL receptor expression by β-catenin in colorectal tumours

Tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) is being investigated as a targeted cancer therapeutic and the expression of its pro-apoptotic receptors, DR4 and DR5, increases during colorectal carcinogenesis. This study investigated the role of β-catenin in the regulation of these receptors. In human colorectal adenoma and carcinoma cell lines, downregulation of β-catenin resulted in lower total DR4 and DR5 protein levels. Similarly, cell membrane expression of DR4 and DR5 was reduced after downregulation of β-catenin in colon carcinoma cells, whereas induction of β-catenin in HeLa cells led to increased cell membrane expression of DR4 and DR5. Downregulation of β-catenin decreased the recombinant human TRAIL sensitivity of human colon carcinoma cells. Activation of the transcription factor T-cell factor-4 (TCF-4) is an important function of β-catenin. Dominant-negative TCF-4 overexpression, however, did not significantly affect TRAIL receptor expression or recombinant human TRAIL sensitivity. Human colorectal adenomas (N = 158) with aberrant (cytoplasmic and nuclear) β-catenin expression had a higher percentage of immunohistochemical DR4 and DR5 staining per tumour (mean: 73 and 88%, respectively) than those with membranous β-catenin staining only (mean: 50 and 70%, respectively, P < 0.01 for both). Furthermore, aberrant β-catenin staining co-localized with DR4 and DR5 expression in 92% of adenomas. In 53 human colorectal carcinomas, aberrant β-catenin expression was present in most cases and DR4/5 expression was largely homogenous. Similarly, in adenomas from APC(min) mice, cytoplasmic β-catenin staining co-localized with staining for the murine TRAIL death receptor. In conclusion, the gradual increase in TRAIL receptor expression during colorectal carcinogenesis is at least partially mediated through increased β-catenin expression, independently of TCF-4-signalling.

Association of plasminogen-activator inhibitor 1 (PAI-1) 4G/5G gene polymorphism with survival and chemotherapy-related vascular toxicity in non-seminomatous testicular cancer (TC)

5083

Background: High PAI-1 expression by tumor has been associated with poor prognosis in different cancer types, while high systemic PAI-1 levels may increase the risk of vascular thrombosis. We investigated whether the 4G/5G del/ins polymorphism in the PAI-1 promoter (rs1799889; 4G might lead to higher transcription), is associated with differences in survival and prevalence of cardiovascular events in TC. Methods: Data were collected on survival and cardiovascular events (venous thromboembolism [VTE] and coronary heart disease [CHD]) of TC patients treated with standard platinum based chemotherapy from 1977–2004. PAI-1 genotype was determined from non-tumor genomic DNA by a Taqman SNP assay. Genotypes were compared for survival (Kaplan-Meier curves + log-rank and Cox-regression analysis), disease outcome (logistic regression) and prevalence of VTE and CHD (χ2-test). Results: Data are available for 324 patients with median follow-up of 10 yrs (range 0–28). The 3 genotypes 4G/4G (n = 84), 4G/5G (n = 164), and 5G/5G (n = 76) do not differ in age and initial chemotherapy regime. However, the 4G/4G variant shows a higher prevalence of International Germ Cell Cancer Classification (IGCCC) poor prognosis compared to 4G/5G + 5G/5G (24% vs 10%; p = 0.003), as well as a decreased TC related survival compared to 4G/5G + 5G/5G (83% vs 94%; p = 0.001) with a hazard ratio of 2.68 for TC related death (95%CI 1.26–5.72; adjusted for IGCCC p = 0.011). In addition, the 4G/4G variant shows an odds ratio of 3.35 for refractory TC and early relapses (<2 yrs) (95% CI 1.48–7.58; p = 0.004). The 3 genotypes do not differ significantly in prevalence of VTE (4G/4G 11.9%, 4G/5G 8.5%, 5G/5G 7.9%; p = 0.616) and CHD during/after chemotherapy (4G/4G 6.0%; 4G/5G 4.9%; 5G/5G 2.6%; p = 0.594). Conclusions: The 4G/4G variant of the PAI-1 4G/5G gene polymorphism is associated with IGCCC poor prognosis, reduced survival and higher prevalence of refractory disease and early relapses. No effect on vascular toxicity was found. The 4G/4G variant of the PAI-1 gene may be an unfavorable prognostic factor as well as an unfavorable predictive factor for response to chemotherapy in patients with TC.

No significant financial relationships to disclose.

Impact of homozygote variant of bleomycin hydrolase (BLMH) gene on survival after chemotherapy for testicular cancer (TC)

5022

Background: With bleomycin, etoposide and cisplatin, cure of disseminated TC exceeds 80%. Next to tumor characteristics, response to chemotherapy may be determined by polymorphisms of genes involved in metabolism or target pathways of cytotoxic drugs. We investigated whether the A1450G polymorphic site in the gene for BLMH, an enzyme that inactivates bleomycin, is associated with differences in survival. Methods: Data were collected on survival of non-seminomatous TC patients treated with bleomycin and platinum from 1977–2003. BLMH genotype was determined from genomic DNA by PCR + restriction fragment length polymorphism analysis. The 3 genotypes [AA (wild-type), AG (heterozygote variant) and GG (homozygote variant)] were compared for patient characteristics, prognostic factors and received chemotherapy (Mann-Whitney U or χ2 test) and survival (Kaplan-Meier + log-rank test and Cox regression). Results: Data on BLMH genotype and survival were available for 304/372 patients (82%) with median follow-up of 10 yrs (range 0–27). The 3 genotypes AA (n=140), AG (n=133) and GG (n=31) did not differ significantly with respect to age, IGCCC prognosis, creatinine clearance and received dose of bleomycin and platinum. Overall survival of the GG genotype (61%) was worse than the overall survival of AA and AG combined (83%) (p=0.004), due to worse TC related survival of GG (71%) compared to AA + AG (90%) (p=0.001). Homozygote variants (GG) had a significantly increased risk for TC related death (odds ratio (OR) = 4.97) compared to wildtypes (AA) ( table ). Conclusion: Germline presence of the homozygote variant (GG) of the BLMH gene appears to be an unfavorable prognostic factor for TC related death after chemotherapy, in addition to the commonly used IGCCC prognosis. It is unclear whether this is due to alterations in metabolism or target pathways of bleomycin or other cytotoxic agents, or linkage disequilibrium to a yet unknown involved gene. This needs to be unraveled in future research.

[Table: see text]

No significant financial relationships to disclose.

Hemochromatosis gene (HFE) mutations and chemotherapy-related cardiovascular risk profile in testicular cancer survivors (TCS)

14589

Background: TCS show an increased incidence of treatment-related cardiovascular disease. Standard chemotherapy (CT) may cause tissue damage by inducing free oxygen radicals through release of redox-active iron from body iron stores. HFE mutations associated with altered body iron load may therefore contribute to an increase in CT-induced free oxygen radicals and tissue damage. We investigated whether two HFE mutations (C282Y and H63D) are associated with cardiovascular risk profile in TCS. Methods: From a group of 90 TCS with a known cardiovascular status (JCO 2005; 23: 3718–25), genomic DNA for genotyping was available for 63 TCS (median (range) age at follow-up 35 y (24–54) and median follow-up duration 7 y (3–13)). Two HFE genotype groups were composed: HFE mutation (mut) (n = 19; any mutation C282Y and/or H63D) and HFE wild type (wt) (n = 44). Both groups were compared for cardiovascular risk profile, using Mann-Whitney U Test or Fisher’s Exact Test. Results: Groups had received comparable CT regimens. Body iron stores as reflected by plasma ferritin and transferrin saturation were not different for the HFE mut vs HFE wt group, respectively 104 μg/l (21–413) vs. 90 μg/l (22–569); p = 0.53 and 31% (20–49) vs. 30% (11–59); p = 0.15. Signs of vascular damage estimated by urinary albumin excretion and Von Willebrand factor levels were not significantly different: respectively 8.3 mg/24 h (4–165) vs. 7.7 mg/24 h (3–647); p = 0.90 and 90% (52–296) vs. 102% (28–235); p = 0.25. The prevalence of cardiovascular risk factors obesity (BMI > 27.8 kg/m2), metabolic syndrome (NCEP ATP III-criteria) and hypertension (mean 24-h blood pressure >135/85 mmHg) are shown in the table. Conclusion: TCS with a mutation in the HFE gene do not show more signs of cardiovascular damage after CT compared to TCS with wt HFE. However, the data suggest that TCS with a HFE mutation may have more frequently cardiovascular risk factors. Further study in a larger group of TCS is needed to explore this observation. [Table: see text]

No significant financial relationships to disclose.

Expression of multidrug resistance proteins, P-gp, MRP1 and LRP, in soft tissue sarcomas analysed according to their histological type and grade

The biological behaviour of different histological types and grades of soft tissue sarcomas (STS) varies. This might result in a differing sensitivity to cytotoxic drugs. Cross-resistance to functionally and structurally distinct natural-product drugs, known as multidrug resistance (MDR), is associated with the overexpression of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and lung resistance-related protein (LRP). The purpose of this study was to evaluate the expression of P-gp, MRP1 and LRP in STS according to their histological type and grade. In 141 chemotherapy-naive STS patients, the expression of the three MDR proteins was detected by immunohistochemistry. Nine histological types were documented. These were 19% grade 1, 34% grade 2 and 47% grade 3 tumours. Expression of P-gp and LRP was observed more frequently than the expression of MRP1 (P<0.0001). P-gp expression was most pronounced in malignant fibrous histiocytoma (MFH), but was low in leiomyosarcomas. MRP1 was expressed in most malignant peripheral nerve sheath tumours (MPNST). LRP was strongly expressed in MFH and unspecified sarcomas, but was low in liposarcomas. MRP1 and LRP expression was significantly more common in grades 2 and 3 compared with grade 1 tumours. P-gp expression was correlated with MRP1, especially in grade 3 STS. In conclusion, P-gp, MRP1 and LRP are expressed in the majority of STS, but this expression varies according to the histological type. MRP1 and LRP, but not P-gp expression, were found to be correlated to tumour grade. MDR might contribute to the observed differences in clinical behaviour within the heterogeneous group of STS.

Calcium affects biomarkers of colon carcinogenesis after right hemicolectomy

BACKGROUND

In Western societies colonic cancer most frequently develops in the distal colon, largely as a result of the composition of the diet. Modulation of dietary factors is therefore an attractive modality to reduce colorectal cancer risk. This study aims to evaluate the potentially protective effects of calcium in right hemicolectomy patients.

MATERIALS AND METHODS

A randomized controlled cross-over intervention trial was performed with 1000 mg of elemental calcium per day for 2 months in 15 right hemicolectomy patients. Primary endpoints were proliferative activity, determined by immunohistochemical detection of BrdU-labeled cells (LI) in rectal biopsies, and cytotoxicity and alkaline phosphatase activity of faecal water. Secondary endpoints were bile acid composition in faeces.

RESULTS

Calcium-reduced LI in the superficial one-third of the crypt (from 0.84 +/- 0.27% to 0.37 +/- 0.08%, P = 0.04) and a trend towards a lower total LI and LI in the mid one-third of the crypt was observed. Alkaline phosphatase activity was reduced from 6.2 +/- 2.6 U mL-1 in the placebo period to 4.6 +/- 2.2 in the calcium period (P = 0.02), and a trend toward a lower cytotoxicity of faecal water was observed. No effect on total bile acids in faeces was observed, but calcium increased the percentage of deoxycholic acid (from 49.6 +/- 7.0% to 56.5 +/- 6.2%, P = 0.03) and decreased the percentages of cholic acid (from 10.3 +/- 4.7% to 5.8 +/- 2.7%, P = 0.05) and lithocholic acid (from 26.7 +/- 3.4% to 23.9 +/- 2.9%, P = 0.04).

CONCLUSION

Calcium may have a protective effect against colorectal cancer risk in right hemicolectomy patients.

Apoptosis induction by sennoside laxatives in man; escape from a protective mechanism during chronic sennoside use?

Chronic sennoside use induces melanosis coli (MC) and possibly increases colorectal cancer risk. Sennosides alter colonic crypt length, proliferative activity, and bcl-2 expression 18 h after administration. To investigate possible mechanisms for carcinogenesis, the effects of acute sennoside use and the presence of MC on colorectal epithelium were studied. Colorectal biopsies from 15 subjects receiving sennosides 6 h before sigmoidoscopy (Sen), 15 controls (NSen), and 27 with MC [11 moderate (MMC) and 16 severe (SMC)]. were analysed for degree of apoptosis (H&E staining), immunohistochemical p53, p21/WAF and bcl-2 expression, and proliferative activity (labelling index, LI). Apoptosis (p=0.0004), intensity of p53 staining (p=0.01), and p21/WAF expression (p=0.008) were increased in Sen and SMC compared with NSen and MMC. p53 expression was increased in Sen (p=0.004). No difference in bcl-2 expression or LI was observed. Crypts were shorter in Sen (p=0.05) and longer in SMC (p=0.04) than in NSen. It is concluded that sennosides acutely induce apoptosis of colonic epithelial cells, presumably by a p53, p21/WAF-mediated pathway, resulting in shorter crypts. In severe melanosis coli, apoptosis seems to be delayed, causing longer crypts without a rise in proliferative activity or bcl-2 expression. This escape from a presumably protective mechanism may enhance the risk of carcinogenesis during chronic sennoside use.

Role of metallothionein in cisplatin sensitivity of germ-cell tumours

Cisplatin (CDDP) is an extremely active drug in the treatment of germ-cell tumours. Earlier, we found an unexpected inverse correlation between the total amount of sulfhydryl groups and CDDP sensitivity in a panel of 3 human germ-cell-tumour and 3 colon-carcinoma cell lines. Major components of the sulfhydryl groups are glutathione and metallothionein (MT). We further investigated a possible role of MT in the CDDP sensitivity of germ-cell tumours. MT levels and functionality of the germ-cell-tumour and colon-carcinoma cell lines were found to be inversely correlated with CDDP sensitivity. No difference in sub-cellular localization of MT could be observed among the types of cell lines. In agreement with the in vitro data, immunohistochemical detection of MT was high in 11/14 primary human germ-cell tumours and low in 7/7 human colon carcinomas. MT-protein expression in primary germ-cell tumours did not discriminate between responding and non-responding patients. As compared with the primary tumours, MT-protein expression decreased in 5/7 post-chemotherapy residual vital tumours or remained undetectable (2/7). MT-protein expression in the germ-cell tumours was not related to total p53-protein expression. In summary, over-expression of MT was found in germ-cell tumours, both in cell lines and in human tumours. Although MT-protein over-expression seems to be associated with the CDDP sensitivity of germ-cell tumours, MT-protein expression in primary germ-cell tumours did not differ between responding and non-responding patients and therefore cannot be used to predict response to chemotherapy.

Proliferation rate of colonic mucosa in normal subjects and patients with colonic neoplasms: a refined immunohistochemical method

An increased colonic epithelial proliferation rate and an increase of the cryptal proliferative zone are probable markers of increased susceptibility to colonic cancer. In this study an immunohistochemical method using 5-bromo-deoxyuridine (BrdUrd) to measure the proliferation rate of colonic mucosa in vitro was used. Fresh endoscopic colonic biopsy specimens were incubated with BrdUrd and then processed for immunohistochemistry using a monoclonal antibody. Essential procedures with respect to the equal distribution of nuclei stained with BrdUrd in the biopsy specimens proved to be the cutting of the specimens before incubation and the use of a microwave oven at the beginning of incubation. The use of the procedure of the running average showed that 12 length cut crypts are sufficient to determine reliably the proliferation rate, expressed as the labelling index (LI). This was determined in the biopsy specimens of 10 subjects without organic colonic disease, eight patients with adenomatous colonic polyps, and in six patients with (recent) colonic carcinoma. Mean LI in the controls was significantly lower than in patients with colonic polyps and in those with colon cancer. It is concluded that this method is promising for screening persons at risk for colon cancer and will be of great potential in performing dietary intervention studies in these subjects.