Spiritual well-being and quality of life among Icelanders receiving palliative care: data from Icelandic pilot-testing of a provisional measure of spiritual well-being from the European Organisation for Research and Treatment of Cancer

Palliative care focuses on improving quality of life (QoL). This study examined the feasibility of the Icelandic version of a provisional European Organisation for Research and Treatment of Cancer (EORTC) measure of spiritual well-being (SWB), and explored the relationship between SWB and QoL for palliative care patients in Iceland. Instruments from the EORTC were used: the provisional measure of SWB, which was undergoing pilot-testing in Iceland, and the EORTC QLQ C15-PAL. The correlation between scores was examined and descriptive statistics were used. Structured interviews explored feasibility. Thirty persons participated with average age 72 years. Belief in God or a higher power had the mean 3.33 on a 1-4 scale and the mean for overall SWB was 5.73 on a 1-7 scale. The mean score for global health/QoL was 59.4, physical functioning 48.5 and emotional functioning 78.9 on a 0-100 scale. Overall QoL was positively correlated with SWB showing r(30) = 0.386, P = 0.035. The participants found that answering the provisional EORTC QLQ-SWB prompted an emotional response and took the opportunity to discuss the subject. The provisional SWB measure was found relevant for the Icelandic context, and the study indicates that SWB and QoL are closely connected.

Gender differences in chronic pain related health care utilization

Aims

To investigate predictors for health-care utilization for chronic pain and whether there are gender differences in variables predicting chronic pain-related health care utilization.

Methods

A postal questionnaire measuring socio-demographic variables, pain characteristics, health related quality of life (HRQoL) and pain related health care utilization, was sent to a sample of 4500 individuals randomly drawn from the national population of Iceland. The relationships between socio-demographic and pain related variables and pain related health care utilization among participants reporting chronic pain (≥3 months) were tested by using bivariate and multivariate statistical analysis.

Results

The prevalence of chronic pain among respondents was 47.5%. Among participants reporting chronic pain, 53.2% had consulted a health care provider for pain during the previous six months.Predictors for pain related health care utilization were pain interference with daily life and pain pattern (daily pain) as well as physical components of HRQoL. Even though health care utilization was not related to gender, there were gender differences in pain-related predictors for health care utilization. Interference with daily life and pain pattern were the strongest predictors among women, but interference with life and the physical components of HRQoL were the strongest predictors for men. Pain related health care utilization was not related to socio-demographic variables.

Conclusions

Pain related variables are better predictors of chronic pain related health care utilization than socio-demographics. Even though gender does not predict chronic pain-related health care utilization, there are gender differences in the relationships between pain-related variables and health care utilization. These gender differences warrant further exploration.

Chronic pain-related patient-provider communication: The significance of health related quality of life and satisfaction

Aims

To investigate patients’ perception of chronic pain related patient-provider communication in relation to socio-demographic and pain-related variables.

Methods

Apostal questionnaire measuring socio-demographic variables, pain characteristics, health-related quality of life (HRQoL), pain-related health care utilization and perceived patient provider communication, was sent to a sample of 4500 individuals randomly drawn from the national population of Iceland. Relationships between patient perceived patient-provider communication and perceived outcome, satisfaction with care as well as sociodemographic and pain-related variables were tested by using bivariate and multivariate statistical analysis.

Results

The prevalence of chronic pain (≥3months) among respondents was 47.5%. Among participants reporting chronic pain, 53.2% had consulted a health care provider for pain during the previous six months. Patients’ perception of providers’ behaviour and control in the communication was mostly related to pain impact on daily life and physical components of HRQoL as well as to patients’ satisfaction with health care providers. The more pain interfered with daily life and impaired patients’ physical health, the more they felt that the provider did not spend time to listen to their concerns and discuss symptoms and treatment options. Patients’ perception of own activity and control in the patient-provider communication and participation in care was related to socio-demographic variables but not with pain related variables.

Conclusions

To be understood as an individual and having their concerns legitimized by the health care provider is crucial for patients when consulting health care for chronic pain. The more pain interferes with daily life and impairs HRQoL, the more important this is. Patients’ perception of own control in patient-provider communication and participation in care is more related to socio-demographics than pain related variables.

The psychometric properties of the Icelandic version of the distress thermometer and problem list

OBJECTIVE

While a significant number of cancer patients experience distress only a minority are offered appropriate psychosocial interventions. Untreated distress can interfere with compliance to treatment and quality of life. The purpose of this study was to evaluate the psychometric properties and feasibility of the Icelandic translation of the distress thermometer (DT) and problem list, a tool developed to screen for distress in cancer patients.  

METHODS

Participants were 149 cancer patients receiving treatment at outpatient oncology clinics at Landspítali-The National University Hospital of Iceland, mean±SD age 59.06 years ±12.92. Participants answered the DT, HADS and GHQ-30, demographic questions and questions regarding the DT.  

RESULTS

Scores on the DT ranged from 0 to 10 with a mean ±SD score of 3.09 ± 2.40, 7.30 ± 4.86 on HADS and 5.28 ± 5.60 on GHQ-30. Significant correlations were between the DT and all categories on the Problem List as well as between the DT and HADS (r = 0.45), and between DT and GHQ-30 (r = 0.57). ROC-analysis supported that a cut-off point of 3 gives the best sensitivity and specificity for the DT predicting depression or anxiety according to the HADS and GHQ. Sixty-nine (48.3%) patients scored < or =2 on DT and 74 (51.7%) scored ≥3.  

CONCLUSION

The Icelandic version of the DT is a valid instrument to screen for distress in clinical practice. The study adds to a growing literature suggesting that this brief instrument may aid in identifying cancer patients suffering from distress and consequently providing appropriate treatment.

Human glutathione transferases catalyzing the bioactivation of anticancer thiopurine prodrugs

cis-6-(2-Acetylvinylthio)purine (cAVTP) and trans-6-(2-acetylvinylthio)guanine (tAVTG) are thiopurine prodrugs provisionally inactivated by an alpha,beta-unsaturated substituent on the sulfur of the parental thiopurines 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG). The active thiopurines are liberated intracellularly by glutathione (GSH) in reactions catalyzed by glutathione transferases (GSTs) (EC 2.5.1.18). Catalytic activities of 13 human GSTs representing seven distinct classes of soluble GSTs have been determined. The bioactivation of cAVTP and tAVTG occurs via a transient addition of GSH to the activated double bond of the S-substituent of the prodrug, followed by elimination of the thiopurine. The first of these consecutive reactions is rate-limiting for thiopurine release, but GST-activation of this first addition is shifting the rate limitation to the subsequent elimination. Highly active GSTs reveal the transient intermediate, which is detectable by UV spectroscopy and HPLC analysis. LC/MS analysis of the reaction products demonstrates that the primary GSH conjugate, 4-glutathionylbuten-2-one, can react with a second GSH molecule to form the 4-(bis-glutathionyl)butan-2-one. GST M1-1 and GST A4-4 were the most efficient enzymes with tAVTG, and GST M1-1 and GST M2-2 had highest activity with cAVTP. The highly efficient GST M1-1 is polymorphic and is absent in approximately half of the human population. GST P1-1, which is overexpressed in many cancer cells, had no detectable activity with cAVTP and only minor activity with tAVTG. Other GST-activated prodrugs have targeted GST P1-1-expressing cancer cells. Tumors expressing high levels of GST M1-1 or GST A4-4 can be predicted to be particularly vulnerable to chemotherapy with cAVTP or tAVTG.

Important needs of families in acute and palliative care settings assessed with the family inventory of needs

Family support has been recognized in the development of palliative care in Iceland, yet studies focusing on family needs are lacking. The aims of this study were to evaluate the perceived care needs of family members of patients receiving palliative care, to what extent these needs were met, and whether needs differed based on background characteristics and site of care. Family members of 111 patients from acute and palliative care settings agreed to participate, and 67 (60%) completed the study. The Family Inventory of Needs was used to quantify family needs and to what extent they were met. All 20 needs measured were considered important. The number of needs did not differ by site of palliative care. Overall, health care professionals met 67% of needs. Needs were more likely to be met in specialized palliative care settings than on acute units and the needs of spouses were more likely to be met than others.

The human multidrug resistance protein MRP5 transports folates and can mediate cellular resistance against antifolates

Members of the multidrug resistance protein family, notably MRP1-4/ABCC1-4, and the breast cancer resistance protein BCRP/ABCG2 have been recognized as cellular exporters for the folate antagonist methotrexate (MTX). Here we show that MRP5/ABCC5 is also an antifolate and folate exporter based on the following evidence: (a) Using membrane vesicles from HEK293 cells, we show that MRP5 transports both MTX (KM = 1.3 mmol/L and VMAX = 780 pmol per mg protein per minute) and folic acid (KM = 1.0 mmol/L and VMAX = 875 pmol per mg protein per minute). MRP5 also transports MTX-glu2 (KM = 0.7 mmol/L and VMAX = 450 pmol per mg protein per minute) but not MTX-glu3. (b) Both accumulation of total [3H]MTX and of MTX polyglutamates were significantly reduced in MRP5 overexpressing cells. (c) Cell growth inhibition studies with MRP5 transfected HEK293 cells showed that MRP5 conferred high-level resistance (>160-fold) against the antifolates MTX, GW1843, and ZD1694 (raltitrexed) in short-term (4 hours) incubations with high drug concentrations; this resistance was proportional to the MRP5 level. (d) MRP5-mediated resistance (8.5- and 2.1-fold) was also found in standard long-term incubations (72 hours) at low concentrations of ZD1694 and GW1843. These results show the potential of MRP5 to mediate transport of (anti)folates and contribute to resistance against antifolate drugs.

Cytotoxicity of the novel glutathione-activated thiopurine prodrugs cis-AVTP [cis-6-(2-acetylvinylthio)purine] and trans-AVTG [trans-6-(2-acetylvinylthio)guanine] results from the National Cancer Institute's anticancer drug screen

cis-6-(2-Acetylvinylthio)purine (cis-AVTP) and trans-6-(2-acetylvinylthio)guanine (trans-AVTG) are glutathione-activated prodrugs of 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG), respectively. Previously, we showed that the prodrugs exhibited less in vivo toxicity in mice than did 6-TG, whereas their in vitro cytotoxicity in two renal cell carcinoma cell lines was comparable with or better than that of their respective thiopurines. To determine whether differences in sensitivity exist among different tissue types toward treatment with cis-AVTP and trans-AVTG, the cytotoxicity of the prodrugs was assessed in the National Cancer Institute's anticancer screening program, and the results were compared with the cytotoxicities of 6-MP and 6-TG obtained in the same screen. The results show that cis-AVTP was more cytotoxic than or equally cytotoxic as 6-MP. Similarly, trans-AVTG was in general more cytotoxic than 6-TG. Both prodrugs exhibited high growth-inhibitory activities in leukemic cells and melanoma cells. However, cis-AVTP was more effective against renal cancer cells than trans-AVTG, whereas trans-AVTG was more effective than cis-AVTP against ovarian cancer cells. Interestingly, analyses using the pattern-recognition algorithm COMPARE revealed that among all compounds in the database, the cytotoxic activity of both cis-AVTP and trans-AVTG correlated best with that of another thiopurine conjugate, NSC 348401 (6-[(7-nitro-2,1,3-benzoxadiazol-4-yl)thio]-9H-purin-2-amine). Collectively, the results show that cis-AVTP and trans-AVTG exhibit both distinct and similar cytotoxicities toward different histotypes. Further investigations into the mechanisms responsible for these differences are warranted.

Distinct tissue distribution of metabolites of the novel glutathione-activated thiopurine prodrugs cis-6-(2-acetylvinylthio)purine and trans-6-(2-acetylvinylthio)guanine and 6-thioguanine in the mouse

The compounds cis-6-(2-acetylvinylthio)purine (cis-AVTP) and trans-6-(2-acetylvinylthio)guanine (trans-AVTG) are glutathione-activated prodrugs of 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG), respectively, that have comparable or lower IC50 values in tumor cells than 6-MP and 6-TG. Previously, we showed that cis-AVTP- and trans-AVTG-treated mice exhibited less bone marrow and intestinal toxicity and excreted a lower fraction of the administered dose in urine than did mice treated with equivalent 6-TG doses. To explain these results, the tissue distribution and levels of metabolites of cis-AVTP, trans-AVTG, and 6-TG were examined at 15, 30, and 45 min after i.p. treatment of mice with equimolar doses of these compounds. After prodrug treatment, the thiopurines, the corresponding thiopurine ribosides and nucleotides, thioxanthine (TX), and thiouric acid (TU) were quantitated in plasma, red blood cells, liver, and intestine. Thiopurine and thiopurine riboside and nucleotide area under the curve between 15 and 45 min [AUC(15-45)] values were generally comparable after cis-AVTP and trans-AVTG treatments but were lower than those after 6-TG treatment. A higher liver/plasma metabolite ratio was evident after trans-AVTG treatment than after cis-AVTP or 6-TG treatments, which exhibited similar liver/plasma ratios. Treatment with cis-AVTP yielded the highest AUC(15-45) for TX and TU in plasma, liver, and intestine. Prodrug treatment did not change the concentration of reduced or oxidized glutathione in tissue homogenates. Collectively, these results show distinct patterns of metabolites depending upon the compound used and suggest that differences in metabolite levels and composition after cis-AVTP, trans-AVTG, and 6-TG treatments may partially explain the different toxicity and urinary metabolite excretion profiles previously observed among cis-AVTP, trans-AVTG, and 6-TG.

The glutathione-activated thiopurine prodrugs trans-6-(2-acetylvinylthio)guanine and cis-6-(2-acetylvinylthio)purine cause less in vivo toxicity than 6-thioguanine after single- and multiple-dose regimens

trans-6-(2-Acetylvinylthio)guanine (trans-AVTG) and cis-6-(2-acetylvinylthio)purine (cis-AVTP) are glutathione-activated prodrugs of 6-thioguanine (6-TG) and 6-mercaptopurine, respectively. In tumor cell lines, these prodrugs exhibit similar IC50 values that are comparable to or lower than those of 6-TG and 6-mercaptopurine, respectively. In this study, the in vivo toxicity and metabolism of the prodrugs were assessed. Mice given multiple treatments of 6-TG and, to a lesser extent, trans-AVTG exhibited decreased peripheral WBC and RBC counts and increased myeloid:erythroid ratios in bone marrow; no change was observed in mice given cis-AVTP. Similarly, intestinal epithelial crypt cell apoptosis was more extensive in mice treated with 6-TG than in those treated with trans-AVTG, whereas mice given cis-AVTP had little apoptosis. Epithelial crypt cell apoptosis was more extensive in the small intestine than in the large intestine in all treatment groups. Histopathological examination detected no kidney or liver toxicity, whereas mild increases in the activities of hepatocellular leakage enzymes were observed in mice treated with trans-AVTG. Only metabolites of trans-AVTG and cis-AVTP were recovered in urine. A higher fraction of the dose was recovered in urine as the parent thiopurine and the metabolites thiopurine riboside, thioxanthine, and thiouric acid after 6-TG treatment than after trans-AVTG treatment; cis-AVTP recovery was slightly less than that of 6-TG. Thioxanthine and thiouric acid comprised a higher fraction of the recovered dose after cis-AVTP treatment than after trans-AVTG or 6-TG treatment. Overall, the results suggest that the prodrugs exhibit less in vivo toxicity than 6-TG. Thus, investigations into their antitumor efficacy are warranted.

Novel glutathione-dependent thiopurine prodrugs: evidence for enhanced cytotoxicity in tumor cells and for decreased bone marrow toxicity in mice

Elevated glutathione (GSH) levels have been detected in many tumors compared with the healthy, surrounding tissue. Often, this GSH up-regulation is associated with drug resistance. The prodrugs 6-(2-acetylvinylthio)guanine (AVTG) and 6-(2-acetylvinylthio)purine (AVTP) contain a novel butenone moiety that allows the prodrugs to react selectively with sulfhydryl nucleophiles to release the chemotherapeutic drug 6-thioguanine (6-TG) or 6-mercaptopurine (6-MP), respectively. The cellular uptake and metabolism of trans-AVTG in two human renal carcinoma cell lines that were used as models were rapid and associated with depletion of intracellular GSH. Formation of 6-TG from trans-AVTG correlated positively with intracellular GSH concentrations, and was significantly reduced by diethyl maleate pretreatment. Intracellular concentrations of 6-TG after incubations with trans-AVTG were significantly higher than the 6-TG concentrations obtained after incubations with equimolar concentrations of 6-TG; thus, the prodrug delivered more 6-TG to the cell than did 6-TG itself. Cytotoxicity studies demonstrated that AVTG and AVTP had similar IC(50) values that were comparable with those of 6-TG, but were significantly lower than those of 6-MP. Furthermore, after in vivo treatment of mice with the prodrugs, no reduction was observed in circulating white blood cell counts, whereas white blood cell counts of mice treated with equimolar or 60% lower doses of 6-TG were reduced by 50 to 60%. Collectively, the results show that AVTG and AVTP are novel potential chemotherapeutic agents that may target tumors with up-regulated levels of GSH, and may exhibit less systemic toxicity than the parent thiopurines.

Endometriosis is not associated with or linked to the GALT gene

OBJECTIVE

To investigate a possible association between the carrier frequency of the N314D mutation in the galactose-1-phosphate uridyl transferase (GALT) gene and endometriosis and linkage to the short arm of chromosome 9, where the GALT gene resides.

DESIGN

Association and linkage study.

SETTING

Population material collected for case and family studies in endometriosis.

PATIENT(S)

Women diagnosed with endometriosis by laparotomy or laparoscopy.

INTERVENTION(S)

Association with the GALT gene investigated by genotyping 85 affected women and 213 unrelated control women and a scan for linkage to chromosome 9 in 205 women from 64 families with endometriosis.

MAIN OUTCOME MEASURE(S)

Multipoint parametric lod scores and frequency of alleles.

RESULT(S)

There was no significant difference in allele frequency for the N314D polymorphism in patients compared with control subjects. No evidence for linkage was found to chromosome 9p, where the GALT gene resides.

CONCLUSION(S)

The experiments reported herein provide no evidence supporting involvement of the GALT locus in the development of endometriosis.

Glutathione-dependent metabolism of cis-3-(9H-purin-6-ylthio)acrylic acid to yield the chemotherapeutic drug 6-mercaptopurine: evidence for two distinct mechanisms in rats

cis-3-(9H-Purin-6-ylthio)acrylic acid (PTA) is a structural analog of azathioprine, a prodrug of the antitumor and immunosuppressive drug 6-mercaptopurine (6-MP). In this study, we examined the in vitro and in vivo metabolism of PTA in rats. Two metabolites of PTA, 6-MP and the major metabolite, S-(9H-purin-6-yl)glutathione (PG), were formed in a time- and GSH-dependent manner in vitro. Formation of 6-MP and PG occurred nonenzymatically, but 6-MP formation was enhanced 2- and 7-fold by the addition of liver and kidney homogenates, respectively. Purified rat liver glutathione S-transferases enhanced 6-MP formation from PTA by 1.8-fold, whereas human recombinant alpha, mu, and pi isozymes enhanced 6-MP formation by 1.7-, 1.3-, and 1.3-fold, respectively. In kidney homogenate incubations, PG accumulation was only observed during the first 15 min because of further metabolism by gamma-glutamyltranspeptidase, dipeptidase, and beta-lyase to yield 6-MP, as indicated by the use of the inhibitors acivicin and aminooxyacetic acid. Based on these results and other lines of evidence, two different GSH-dependent pathways are proposed for 6-MP formation: an indirect pathway involving PG formation and further metabolism to 6-MP, and a direct pathway in which PTA acts as a Michael acceptor. HPLC analyses of urine of rats treated i.p. with PTA (100 mg/kg) showed that 6-MP was formed in vivo and excreted in urine without apparent liver or kidney toxicity. Collectively, these studies show that PTA is metabolized to 6-MP both in vitro and in vivo and may therefore be a useful prodrug of 6-MP.