Seizing the moment: The time for harnessing electronic patient-reported outcome measures for enhanced and sustainable metastatic breast cancer care is now.

The sustainability of healthcare systems is under pressure. Unlike care for many other chronic diseases, cancer care has yet to empower patients in effectively self-managing both the medical and emotional consequences of their condition, including adapting to changes in lifestyle and work, which is essential to achieve optimal health and recovery. Although proposed as a potential solution for sustainable healthcare and support for optimal health and recovery already decades ago, practical implementation of digital care lags behind. We believe electronic patient reported outcome measures (ePROMs) could play an important role in creating sustainable healthcare, both to guide complex treatment pathways and to empower survivors to self-manage consequences of diagnosis and treatment. That is, ePROMs can be used for screening and monitoring of symptoms, but also for treatment decision-making and to facilitate communication about quality of life. We therefore see opportunities for improvements in quality of care, quality of life, and survival of cancer patients, as well as research opportunities, as ePROMs collection can lead to better understanding of care needs. The '10 Actions for Change report' of the Advanced Breast Cancer Global Alliance stresses a critical need for improvement of care for metastatic breast cancer (MBC) patients. We therefore in this paper focus on MBC care and research.

Cancer worry is associated with increased use of supportive health care-results from the multinational InCHARGE study.

PURPOSE: To assess use of health care following a diagnosis of endometrial, cervical, and ovarian cancer in the Netherlands, Norway, and Denmark. Furthermore, to analyze the association between cancer worry and use of supportive care. METHODS: An international multicenter cross-sectional questionnaire study was undertaken among female cancer survivors with endometrial, cervical, or ovarian cancer 1-7 years post diagnosis. We investigated different aspects of cancer survivorship and follow-up care. Health care use included information on the use of supportive health care, general practitioner (GP), and follow-up visits to the department of gynecology. Cancer worry was assessed with the Impact of Cancer (IoCv2) questionnaire. RESULTS: A total of 1433 women completed the questionnaire. Health care use decreased from time of diagnosis and was higher among cervical and ovarian cancer survivors than endometrial cancer survivors. Twenty-five percent of the women with ovarian cancer reported severe cancer worry, in contrast to 10 and 15% of women diagnosed with endometrial and cervical cancer, respectively. Women with severe worry had significantly higher use of supportive care activities. In a multivariable regression analysis, cancer worry remained a significant correlate for use of supportive health care services irrespective of disease severity or prognosis. The strongest association was found for use of a psychologist (OR 2.1 [1.71-2.58]). CONCLUSION: Cancer worry is associated with increased use of supportive care. IMPLICATIONS FOR CANCER SURVIVORS: Targeted, timely, and accessible psychological support aimed at severe cancer worry may improve survivorship care and ensure optimal referral of patients in need of additional care.

International development of a patient-centered core outcome set for assessing health-related quality of life in metastatic breast cancer patients.

PURPOSE: For patients living with metastatic breast cancer (MBC), achieving best possible health-related quality of life, along with maximizing survival, is vital. Yet, we have no systemic way to determine if we achieve these goals. A Core Outcome Set (COS) that allows standardized measurement of outcomes important to patients, but also promotes discussing these outcomes during clinical encounters, is long overdue. METHODS: An international expert group (EG) of patient advocates, researchers, medical specialists, nurse specialists, and pharmaceutical industry representatives (n = 17) reviewed a list of relevant outcomes retrieved from the literature. A broader group (n = 141: patients/patient advocates (n = 45), health care professionals/researchers (n = 64), pharmaceutical industry representatives (n = 28), and health authority representatives (n = 4)) participated in a modified Delphi procedure, scoring the relevance of outcomes in two survey rounds. The EG finalized the COS in a consensus meeting. RESULTS: The final MBC COS includes 101 variables about: (1) health-related quality of life (HRQoL, n = 26) and adverse events (n = 24); (2) baseline patient characteristics (n = 9); and (3) clinical variables (n = 42). Many outcome that cover aspects of HRQoL relevant to MBC patients are included, e.g. daily functioning (including ability to work), psychosocial/emotional functioning, sexual functioning, and relationship with the medical team. CONCLUSION: The COS developed in this study contains important administrative data, clinical records, and clinician-reported measures that captures the impact of cancer. The COS is important for standardization of clinical research and implementation in daily practice and has received accreditation by the International Consortium for Health Outcomes Measurement (ICHOM).

Adjustment disorder in cancer patients after treatment: prevalence and acceptance of psychological treatment.

PURPOSE: To investigate the prevalence of adjustment disorder (AD) among cancer patients and the acceptance of psychological treatment, in relation to sociodemographic, clinical, and psychological factors. METHODS: Breast, prostate, and head and neck cancer patients of all stages and treatment modalities (N = 200) participated in this observational study. Patients completed the Hospital Anxiety and Depression Scale, Checklist Individual Strength, Distress Thermometer and problem list. Patients with increased risk on AD based on these questionnaires were scheduled for a diagnostic interview. Patients diagnosed with AD were invited to participate in a randomized controlled trial on the cost-effectiveness of psychological treatment. Participation in this trial was used as a proxy of acceptance of psychological treatment. Logistic regression analyses were used to investigate associated factors. RESULTS: The overall prevalence of AD was estimated at 13.1%. Sensitivity analyses showed prevalence rates of AD of 11.5%, 15.0%, and 23.5%. Acceptance of psychological treatment was estimated at 65%. AD was associated both with being employed (OR = 3.3, CI = 1.3-8.4) and having a shorter time since diagnosis (OR = 0.3, CI = 0.1-0.8). CONCLUSION: Taking sensitivity analysis into account, the prevalence of AD among cancer patients is estimated at 13 to 15%, and is related to being employed and having a shorter time since diagnosis. The majority of cancer patients with AD accept psychological treatment.

Perceived social support in patients with endometrial or ovarian cancer: A secondary analysis from the ROGY care study.

OBJECTIVE: Social support may reduce the amount of psychological distress and increase quality of life. This study assessed whether socio-demographic, personality, and clinical characteristics predict the level of perceived social support in patients with endometrial or ovarian cancer. METHODS: Patients with endometrial or ovarian cancer who participated in the ROGY Care study and completed the Multidimensional Scale of Perceived Social Support(MSPSS) 12 months after inclusion were eligible for this study (n=238). Logistic regression analysis was conducted to determine the predictive value of socio-demographic characteristics, personality and clinical characteristics after initial treatment on the perceived level of social support after 12 months. RESULTS: Of the 238 patients (mean age 64.8 ± 9.4 years), 139 patients had endometrial cancer (58%) and 99 patients had ovarian cancer (42%). One year after inclusion, the level of perceived social support was high in 79% of all patients (n=189). Patients experiencing low level of perceived social support (n=49) less often had a partner (69% versus 83% in patients with high level of perceived social support; p=0.029), had a higher education level (24% versus 15% respectively; p=0.013) and a distressed (type D) personality was more common (40% versus 16% respectively; p<0.001). In multivariable analysis, a type D personality, characterized by negative affect and social inhibition, was the only independent predictor of a low level of perceived social support (OR 2.96; 95% CI 1.37-6.37; p=0.006). CONCLUSIONS: In patients with endometrial or ovarian cancer, the level of perceived social support is mainly associated with a distressed (type D) personality. Those patients can be at risk of experiencing less social support. Future research is needed to assess whether they might benefit from additional support during cancer diagnosis and treatment.

The age-related impact of surviving sarcoma on health-related quality of life: data from the SURVSARC study.

BACKGROUND: Health-related quality of life (HRQoL) data of sarcoma survivors are scarce and the impact of age remains unclear. The aims of this population-based study were to (i) compare HRQoL scores amongst three age-groups [adolescents and young adults (AYA, aged 18-39 years), older adults (OA, aged 40-69 years) and elderly (aged ≥70 years)]; (ii) compare HRQoL of each sarcoma survivor age group with an age- and sex-matched normative population sample; (iii) determine factors associated with low HRQoL per age group. METHODS: Dutch sarcoma survivors, who were 2-10 years after diagnosis, were invited to complete the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30-questions questionnaire on HRQoL. RESULTS: In total, 1099 survivors (58% response rate) completed the questionnaire: 186 AYAs, 748 OAs and 165 elderly. The median time since diagnosis for all patients was 5.2 years. Bone sarcomas were seen in 41% of AYAs, 22% of OAs and in 16% of elderly survivors (P < 0.01). AYA and OA survivors reported statistically significant and clinically meaningful worse physical, role, cognitive, emotional and social functioning compared with a matched norm population, which was not the case for elderly survivors. AYAs reported significantly worse scores on emotional and cognitive functioning compared with OA and elderly survivors. Malignant peripheral nerve sheath tumour, osteosarcoma and chordoma were the subtypes of which survivors reported the lowest HRQoL scores in comparison with the norm. For all age groups, chemotherapy, having a bone sarcoma and having comorbidities were most frequently associated with low scores on HRQoL subscales, whereas a shorter time since diagnosis was not. CONCLUSION: In this nationwide sarcoma survivorship study, the disease and its treatment had relatively more impact on the HRQoL of AYA and OA survivors than on elderly survivors. These results emphasise the need for personalised follow-up care that not only includes risk-adjusted care related to disease relapse, but also age-adjusted care.

Acute cellular rejection is associated with matrix metalloproteinase-2 genotype chimerism after orthotopic liver transplantation.

PURPOSE: Chimerism in transplantation medicine refers to the coexistence of cells of donor and recipient origin. Their existence in relation to possible pathological mechanisms remains largely unknown. We used donor-recipient mismatches for matrix metalloproteinases (MMP) gene polymorphisms in liver biopsies and in blood as a marker for chimerism after orthotopic liver transplantation (OLT). The second aim of this study was to evaluate these polymorphisms in relation to clinical outcome such as ischemia-reperfusion injury (IRI) and acute cellular rejection (ACR). METHODS: MMP-2 and MMP-9 promoter polymorphism donor-recipient mismatches were determined in 147 OLT patients. The relationship between these MMP polymorphism mismatches in donor and recipient DNA with the development of IRI and ACR after OLT was evaluated. Liver biopsy specimens and peripheral blood samples were subsequently evaluated for the presence of chimerism, also in relation to these complications. RESULTS: MMP polymorphism donor-recipient mismatches were found in 53.7% (MMP-2) and 35.5% (MMP-9) of the OLT patients but no relation was observed with IRI or ACR. Chimerism in liver biopsy specimens was found to be present in 28.8% (MMP-2) and 16.2% (MMP-9) of the cases. Liver chimerism in MMP-2 was found to be significantly associated with ACR after OLT (χ(2) 6.4, P = .01). Multivariate analysis revealed MMP-2 chimerism to be an independent risk factor for ACR after OLT even adjusted for Model for End-stage Liver Disease score (hazard ratio = 3.83, P = .03). In addition, evidence of donor chimerism was found in peripheral blood samples of the recipients in some cases. CONCLUSION: Chimerism after OLT can be found in liver biopsy specimens and in peripheral blood. MMP donor-recipient polymorphism mismatches are good markers for assessing chimerism after OLT. In the multivariate analysis, liver chimerism in MMP-2 was found to be significantly associated with the development of ACR after OLT.

The BMP2/7 heterodimer inhibits the human breast cancer stem cell subpopulation and bone metastases formation.

Accumulating evidence suggests that a subpopulation of breast cancer cells, referred to as cancer stem cells (CSCs), have the ability to propagate a tumor and potentially seed new metastases. Furthermore, stimulation of an epithelial-to-mesenchymal transition by factors like transforming growth factor-ß (TGFß) is accompanied with the generation of breast CSCs. Previous observations indicated that bone morphogenetic protein-7 (BMP7) antagonizes the protumorigenic and prometastatic actions of TGFß, but whether BMP7 action is mechanistically linked to breast CSCs has remained elusive. Here, we have studied the effects of BMP7, BMP2 and a BMP2/7 heterodimer on the formation of human breast CSCs (ALDH(hi)/CD44(hi)/CD24(-/low)) and bone metastases formation in a preclinical model of intra-cardiac injection of MDA-MB-231 cells in athymic nude (Balb/c nu/nu) mice. The BMP2/7 heterodimer was the most efficient stimulator of BMP signaling and very effectively reduced TGFß-driven Smad signaling and cancer cell invasiveness. The tested BMPs-particularly the heterodimeric BMP2/7-strongly reduced the size of the ALDH(hi)/CD44(hi)/CD24(-/low) CSC subpopulation. In keeping with these in vitro observations, pretreatment of cancer cells with BMPs for 72 h prior to systemic inoculation of the cancer cells inhibited the formation of bone metastases. Collectively, our data support the notion that breast CSCs are involved in bone metastasis formation and describe heterodimeric BMP2/7 as a powerful TGFß antagonist with anti-metastatic potency.

Urinary metabolite profile of phenyl and o-cresyl glycidyl ether in rats: identification of a novel pathway leading to N-acetylserine O-conjugates.

The urinary excretion of metabolites of phenyl glycidyl ether (PGE) and o-cresyl glycidyl ether (o-CGE) was investigated in rats. Urine was collected, in fractions, from rats intraperitoneally administered PGE or o-CGE in doses ranging from 0.033 to 1.0 mmol/kg. The metabolites were extracted from acidified urine with ethyl acetate or diethyl ether, and their identity was elucidated by GC/MS analysis. The epoxide of PGE can be inactivated by glutathione (GSH) conjugation or epoxide hydrolysis. After further metabolism, these routes lead to the urinary excretion of phenyl glycidyl ether mercapturic acid (PGEMA) and 3-(phenyloxy)lactic acid (POLA). The excretion of PGEMA and POLA was described before and is confirmed in this study. Additionally, a new metabolite was identified as N-acetyl-O-phenylserine (NAPS), which is proposed to be formed from POLA by subsequent oxidation, transamination, and N-acetylation. For PGEMA a linear dose-excretion relationship was found (r2 = 0.988), and the percentage of the dose excreted declined from 27% to 10% with increasing PGE dose. For NAPS also a linear dose-excretion relationship was found (r2 = 0.985), and NAPS accounted for 27% of the PGE dose. The excretion of PGEMA and NAPS was rather fast: 93% and 75%, respectively, of the respective total cumulative amounts excreted was already collected within 6 h after administration. The urinary metabolite profile of o-CGE was not investigated in rats before. Three urinary metabolites of o-CGE were identified, namely, 3-(o-cresyloxy)lactic acid (COLA), o-cresyl glycidyl ether mercapturic acid (o-CGEMA), and N-acetyl-O-(o-cresyl)serine (NACS), showing that the metabolite profiles of PGE and o-CGE are comparable. Up to a o-CGE dose of 0.333 mmol/kg, the excretion of o-CGEMA was linear (r2 = 0.997), while above this dose the excretion did not increase anymore. The percentage of the o-CGE dose excreted as o-CGEMA declined from 31% to 11% with increasing dose. Again 93% of the total cumulative amount of o-CGEMA excreted was collected within 6 h after administration of o-CGE. Analytical methods were developed for the quantitative determination of mercapturic acid metabolites of PGE and o-CGE. These methods were sufficiently sensitive for their determination in urine of rats administered PGE or o-CGE in the dose range applied. It is anticipated that the analytical methods developed are also sufficiently sensitive to investigate excretion of the mercapturic acid metabolites in humans occupationally exposed to low air concentrations (<6 mg/m3 of air, 8h-TWA) of PGE or o-CGE.

Allylmercapturic acid as urinary biomarker of human exposure to allyl chloride.

OBJECTIVE: To evaluate the use of urinary mercapturic acids as a biomarker of human exposure to allyl chloride (3-chloropropene) (AC). During three regular shut down periods in a production factory for AC, both types of variables were measured in 136 workers involved in maintenance operations. METHODS: Potential airborne exposure to AC was measured by personal air monitoring in the breathing zone. In total 205 workshifts were evaluated. During 99 workshifts no respiratory protection equipment was used. Mercapturic acid metabolites were measured in urinary extracts by gas chromatography-mass spectrometry (GC-MS). RESULTS: During 86 work shifts when no respiratory protection was used the air concentrations of AC were below the Dutch eight hour time weighted average (8 h-TWA) occupational exposure limit (OEL) of AC (3 mg/m3), whereas in 13 workshifts the potential exposure, as measured by personal air monitoring, exceeded the OEL (3.3 to 17 mg/m3). With the aid of GC-MS, 3-hydroxypropylmercapturic acid (HPMA) was identified as a minor and allylmercapturic acid (ALMA) as a major metabolite of AC in urine samples from the maintenance workers exposed to AC. The concentrations of ALMA excreted were in a range from < 25 micrograms/l (detection limit) to 3550 micrograms/l. The increases in urinary ALMA concentrations during the workshifts correlated well with the 8h-TWA air concentrations of AC (r = 0.816, P = 0.0001, n = 39). Based on this correlation, for AC a biological exposure index (BEI) of 352 micrograms ALMA/g creatinine during an eight hour workshift is proposed. In some urine samples unexpectedly high concentrations of ALMA were found. Some of these could definitely be attributed to dermal exposure to AC. In other cases garlic consumption was identified as a confounding factor. CONCLUSION: The mercapturic acid ALMA was identified in urine of workers occupationally exposed to airborne AC and the increase in ALMA concentrations in urine during a workshift correlated well with the 8 h-TWA exposure to AC. Garlic consumption, but not smoking, is a potential confounding factor for this biomarker of human exposure to AC.

3-Chloro-2-hydroxypropylmercapturic acid and α-chlorohydrin as biomarkers of occupational exposure to epichlorohydrin.

Until now no urinary biomarker of exposure was available to assess human exposure to epichlorohydrin (ECH). For this purpose the urinary excretion of mercapturic acids and α-chlorohydrin (α-CH), which are potential metabolites of ECH in humans was investigated. This study was undertaken in a chemical plant in which ECH is used in the production of glycidyl ethers. Urine samples were collected from 19 persons at the beginning and at the end of work-shifts and at the morning after the last work-shift. Respiratory air concentrations of ECH were determined by personal air monitoring (PAM) and were found to range from<0.03 to 1.1 mg/m(3) (8 h-TWA, median 0.09, n=23). The determined respiratory exposure to ECH was in all cases below the current occupational exposure limit of 4 mg/m(3) for ECH (8 h-TWA-OEL). In one additional case a dermal exposure to an unknown amount of technical ECH was noted. Urinary metabolites were isolated by ethyl acetate extraction or by lyophilization and determined by GC-MS. In ethyl acetate extracts of acidified urine samples of workers with potential occupational exposure to ECH, 3-chloro-2-hydroxypropylmercapturic acid (CHPMA) was identified with GC-MS and the concentrations measured ranged from<0.05 (detection limit) to 5.35 mmol/mol creatinine. The increase of the CHPMA excretion during the work-shifts, corrected for creatinine excretion, correlated well with the 8 h-TWA respiratory air concentrations of ECH (r(2)=0.94, n=7). For 8 individuals it was possible to assess an urinary half-life for the excretion of CHPMA (2.54±0.94 h). By extrapolating the relation between the ambient air concentrations of ECH and the urinary CHPMA excretions, an excretion of 6.2 mmol CHPMA/mol creatinine (tolerance levels of 95% C.I.: 5.1-7.3) is predicted if ECH exposure is at the level of the current OEL. The urinary excretion of two other known metabolites of ECH in rats, namely α-CH and 2,3-dihydroxypropylmercapturic acid (DHPMA) was also investigated. α-CH was identified in urine of workers exposed to low air concentrations of ECH but DHPMA could only be identified after the dermal exposure to technical ECH. In these latter samples CHPMA and α-CH were determined up to 167 and 6.3 mmol/mol creatinine, respectively. From this investigation it is concluded that urinary excretion of the mercapturic acid CHPMA is an appropriate biomarker of human exposure to ECH. A tentative biological exposure index (BEI) of 6 mmol CHPMA/mol creatinine for ECH during an 8 h work-shift is proposed.

Identification and quantitative determination of 3-chloro-2-hydroxypropylmercapturic acid and alpha-chlorohydrin in urine of rats treated with epichlorohydrin.

Epichlorohydrin (ECH) is used in many industrial processes. Different toxic effects of ECH were found in rodents. The metabolism of ECH was investigated before in rats using [14C]ECH. The aim of this investigation was the development of non-radioactive quantitative analytical methods for measuring two urinary metabolites of ECH, namely 3-chloro-2-hydroxypropylmercapturic acid (CHPMA) and alpha-chlorohydrin (alpha-CH). The identity of CHPMA and alpha-CH excreted in urine of rats treated with 5 to 35 mg/kg ECH was confirmed by GC-MS. The quantitative analysis of CHPMA, involving ethyl acetate extraction from acidified urine and subsequent methylation and analysis by gas chromatography-flame photometric detection (GC-FPD), showed a method limit of detection of 2 micrograms/ml. The analysis of alpha-CH based on ethyl acetate extraction and subsequent analysis by GC-ECD, showed a method limit of detection of 2 micrograms/ml. CHPMA and alpha-CH derivatives could be determined quantitatively down to concentrations of 0.5 and 0.4 micrograms/ml urine, respectively, by selected-ion monitoring GC-MS under EI conditions. Cumulative urinary excretion of CHPMA and alpha-CH by rats treated with ECH were found to be 31 +/- 10 and 1.4 +/- 0.6% (n = 13) of the ECH dose, respectively. For CHPMA, the dose-excretion relationship suggested partially saturated ECH metabolism. For alpha-CH, the doe-excretion relationship was linear. With fractionated urine collection it was found that approximately 74 and 84% of the total cumulative excretion of CHPMA and alpha-CH, respectively, took place within the first 6 h after administration of ECH. From these investigations it is concluded that the GC-FPD and GC-ECD based methods developed are sufficiently sensitive to measure urinary excretion of CHPMA and alpha-CH in urine from rats administered 5 to 35 mg/kg ECH. It is anticipated that the analysis of CHPMA and alpha-CH based on GC-MS may be sufficiently sensitive to investigate urinary excretion from humans occupationally exposed to ECH.

Biotransformation of allyl chloride in the rat. Influence of inducers on the urinary metabolic profile.

Allyl chloride (AC) is used as intermediate in the synthesis of epichlorohydrin (ECH). We investigated the biotransformation of AC in rats to select potential urinary biomarkers of exposure. For this purpose, we developed analytical methods to measure different selected urinary metabolites of AC. The earlier described urinary metabolites of AC [allyl mercapturic acid (ALMA) and 3-hydroxypropyl mercapturic acid (HPMA)], as well as two urinary metabolites of ECH [alpha-chlorohydrin (alpha-CH) and 3-chloro-2-hydroxypropyl mercapturic acid (CHPMA)], were determined in this study. After intraperitoneal administration of AC, in doses ranging from 66 to 590 mumol/kg, control rats excreted 30 +/- 6.5% of the AC dose as ALMA. HPMA was a minor urinary metabolite of AC (< 3% of the AC dose), and, for this metabolite, no clear dose-excretion relationship was found. Two other minor urinary metabolites were also found as well, namely CHPMA and alpha-CH, suggesting the formation of ECH. CHPMA excretion was linear from 66 to 330 mumol/kg AC and amounted to 0.21 +/- 0.08% of the AC dose. alpha-CH excretion was linear in the dose range used and was excreted for 0.13 +/- 0.02% of the AC dose. In addition, we investigated the influence of three different enzyme inducers on the urinary metabolite profile of AC, namely pyrazole, beta-naphthoflavone, and phenobarbital. Pyrazole only increased the urinary excretion of alpha-CH. beta-Naphthoflavone induction only enhanced the ALMA excretion significantly. Phenobarbital inducted both the excretion of CHPMA and alpha-CH. From these studies, we conclude that urinary excretion of ALMA, CHPMA, and alpha-CH can be used as biomarkers in humans potentially exposed to AC. However, ALMA seems to be the more appropriate biomarker, because enzyme induction may play a confounding role if CHPMA or alpha-CH is used.

Urinary excretion of N-acetyl-S-allyl-L-cysteine upon garlic consumption by human volunteers.

N-Acetyl-S-allyl-L-cysteine (allylmercapturic acid, ALMA) was previously detected in urine from humans consuming garlic. Exposure of rats to allyl halides is also known to lead to excretion of ALMA in urine. ALMA is a potential biomarker for exposure assessment of workers exposed to allyl halides. It is not known whether garlic consumption can lead to urinary concentrations of ALMA which may interfere with biological monitoring of exposure to allyl halides by determination of urinary ALMA. Therefore, this study was undertaken to determine the cumulative excretion and the excretion kinetics of ALMA in urine of humans consuming garlic. Six human volunteers were given orally two garlic tablets, each containing 100 mg garlic extract (each representing 300 mg fresh garlic). Three of the volunteers consumed additional garlic after the garlic tablet intake. Urine samples were collected up to 24 h after the intake of the garlic tablets. ALMA was identified in the urine using gas chromatography-mass spectrometry (GC-MS) and determined quantitatively with a limit of detection of 0.10 microgram/ml with gas chromatography with sulphur selective detection. The total amount of ALMA found in urine of volunteers who consumed two garlic tablets was 0.43 +/- 0.14 mg (n = 3). In the urine of the three volunteers who consumed not only two garlic tablets but also additional fresh garlic, a significantly higher amount of ALMA was excreted in the urine, 1.4 +/- 0.2 mg (n = 3). The elimination half-life of ALMA, estimated from urinary excretion rate versus time curves, was 6.0 +/- 1.3 h (n = 5). One volunteer, who ate additional garlic, showed an irregular elimination profile and was excluded from this estimation. The highest urinary concentration of ALMA found in this study was 2.2 micrograms/ml. In a preliminary biological monitoring study of exposure in workers with potential exposure to allyl chloride (AC) up to the occupational exposure limit of 1 ppm (8-h TWA), we recently found urinary ALMA concentrations up to 4 micrograms/ml. Based on the results presented here, we conclude that garlic consumption is a potential confounder when monitoring human exposure to allylhalides and other chemicals leading to ALMA excretion when ALMA is used as a biomarker of exposure.

Mechanism of the reaction of ebselen with endogenous thiols: dihydrolipoate is a better cofactor than glutathione in the peroxidase activity of ebselen.

The therapeutic effect of ebselen has been linked to its peroxidase activity. In the present study, the peroxidase activity of ebselen toward H2O2 with the endogenous thiols GSH and dihydrolipoate [L(SH)2] as cofactors was determined. When GSH was used, peroxide removal was described by a ter uni ping pong mechanism with Dalziel coefficients for GSH and H2O2 of 0.165 +/- 0.011 and 0.081 +/- 0.005 mM min, respectively. When L(SH)2 was used, peroxidase activity was independent of the concentration of L(SH)2 in the concentration range studied (5 microM to 2 mM) and peroxide removal was only dependent on the concentration of H2O2 and ebselen, with the second-order rate constant being 12.3 +/- 0.8 mM-1 min-1. To elucidate the difference between GSH and L(SH)2, the molecular mechanism of the peroxidase activity of ebselen was investigated, using UV spectrophotometry, high pressure liquid chromatography, 77Se NMR, and mass spectrometry. GSH was found to react quickly with ebselen to give a selenenyl sulfide, an adduct of GSH to ebselen. Subsequently, the GSH-selenenyl sulfide is converted into the diselenide of ebselen. Finally the diselenide reacts with a peroxide and ebselen is regenerated. The formation by GSH of the diselenide from the GSH-selenenyl sulfide of ebselen is slow and linearly dependent on the concentration of free thiol; however, no net consumption of GSH was observed. Furthermore, it is likely that a selenol is an intermediate in diselenide formation. After reaction between ebselen and L(SH)2 the diselenide of ebselen was immediately detected. The fast formation of the diselenide with L(SH)2 versus the slow formation of the diselenide with GSH accounts for our observation that L(SH)2 is a better cofactor than GSH in the peroxidase activity of ebselen. Our results suggest that the interaction between ebselen and L(SH)2 might be of major importance in the mechanism by which ebselen exerts its therapeutic effect.

Beta-adrenoceptor agonists do not reduce hydrogen peroxide production from superoxide radicals.

Recently, it has been reported that beta-adrenoceptor agonists containing a catechol moiety, reduce hydrogen peroxide production by alveolar macrophages, an effect suggested to be due to scavenging by the catecholamines of superoxide, the precursor of hydrogen peroxide. However, catecholamines interfere with the method used, in that study, to determine hydrogen peroxide formation. We re-examined the obtained results using two independent methods for measuring hydrogen peroxide that are not affected by catecholamines. We found that catecholamines, in a concentration up to 10(-5) M, had no effect on hydrogen peroxide formation out of superoxide. It was, furthermore, established that reduction of hydrogen peroxide formation by scavenging of superoxide by catecholamines is not very likely.