Medication error awareness among health care providers in Palestine: A questionnaire-based cross-sectional observational study.

Background: Increased awareness among healthcare professionals regarding medication errors and the establishment of a medication error reporting system can significantly reduce the prevalence of medication errors. Unfortunately, Palestine lacks a regulatory system for the control, reporting, and education of medication errors. Objectives: This study aimed to assess the awareness of medication errors and reporting of medication errors in the Palestinian medical community. Methods: A cross-sectional observational study was conducted using a self-administered survey involving doctors, nurses, and pharmacists in Palestine. The survey consisted of 20 questions to assess healthcare providers' awareness and course of actions related to medication errors. Data were collected from February 2020 to April 2020. Statistical Package for the Social Sciences (SPSS) was used for data analysis. This study was approved by the ethical committee of Birzeit University. Results: A total of 394 participants were included, including 202 nurses, 114 doctors, and 78 pharmacists. 203 (51.5%) had a good awareness level of medication errors, whereas 126 (32%) and 65 (16.5%) had average awareness and poor awareness levels, respectively. In addition, 66.0% of providers did not inform the patients after recognizing the error. Fear of legal or social consequences and being too busy are significant barriers to reporting medication errors. Moreover, 35 % of all providers were not aware of the reporting system in their institutions or the reporting methodology, and only 26% of all participants confirmed that their institutions provided continuous education on medication errors. Conclusion: This study revealed differences in healthcare professionals' awareness of medication errors. The study's findings emphasize the urgent need to adopt appropriate measures to raise awareness about medication errors among healthcare providers in Palestine. Furthermore, establishing a regulatory policy and a national medication error reporting system to improve medication safety.

The Value of Hope: Patients' and Physicians' Preferences for Survival in Advanced Non-Small Cell Lung Cancer.

PURPOSE: Immuno-oncology treatments offer patients with advanced non-small cell lung cancer (NSCLC) treatment options with greater probability of durable survival and a different toxicity profile compared with traditional chemotherapy. The objective of this study was to explore the importance of increases in the probability of long-term survival versus changes in expected (median) survival and treatment toxicities among patients with advanced NSCLC and physicians. PATIENTS AND METHODS: In a discrete-choice experiment, oncologists and patients diagnosed with NSCLC chose between profiles of treatments for advanced NSCLC offering different combinations of benefits (expected, best-case, and worst-case survival) and risks. We analyzed preference data from each sample using a random-parameters logit model that controls for preference heterogeneity and the panel nature of the data. RESULTS: Both patients and physicians expressed a strong preference for improving the probability of best-case survival; however, patients viewed increases in the probability of long-term survival as more important than increases in expected survival, while the opposite was true for physicians. Both patients and physicians weighted survival to be more important than toxicities. CONCLUSION: This study identified a potentially important divergence between physician and patient perspectives on survival statistics. Physicians placed more importance on increases in expected survival than did patients with NSCLC. The importance patients placed on long-term survival reinforce previous research identifying the primacy of hope as a value among seriously ill patients. The findings underscore the importance of considering patients' priorities and in shared decision-making when choosing treatment.

Labrador tea (Rhododendron groenlandicum) attenuates insulin resistance in a diet-induced obesity mouse model.

PURPOSE: Using a diet-induced obesity (DIO) mouse model, we investigated the antidiabetic effect of Labrador tea [Rhododendron groenlandicum (Oeder) Kron and Judd], a beverage and medicinal tea used by the Cree Nations of northern Quebec. METHODS: C57BL6 mice were divided into five groups and given standard chow (~4 % of lipids) or high-fat diet (~35 % of lipids) for 8 weeks until they became obese and insulin resistant. Treatment began by adding the plant extract at three doses (125, 250 and 500 mg/kg) to the high-fat diet for another 8 weeks. At the end of the study, insulin-sensitive tissues (liver, skeletal muscle, adipose tissue) were collected to investigate the plant's molecular mechanisms. RESULTS: Labrador tea significantly reduced blood glucose (13 %), the response to an oral glucose tolerance test (18.2 %) and plasma insulin (65 %) while preventing hepatic steatosis (42 % reduction in hepatic triglyceride levels) in DIO mice. It stimulated insulin-dependent Akt pathway (55 %) and increased the expression of GLUT4 (53 %) in skeletal muscle. In the liver, Labrador tea stimulated the insulin-dependent Akt and the insulin-independent AMP-activated protein kinase pathways. The improvement in hepatic steatosis observed in DIO-treated mice was associated with a reduction in inflammation (through the IKK α/ß) and a decrease in the hepatic content of SREBP-1 (39 %). CONCLUSIONS: Labrador tea exerts potential antidiabetic action by improving insulin sensitivity and mitigating high-fat diet-induced obesity and hyperglycemia. They validate the safety and efficacy of this plant, a promising candidate for culturally relevant complementary treatment in Cree diabetics.

A combination of (+)-catechin and (-)-epicatechin underlies the in vitro adipogenic action of Labrador tea (Rhododendron groenlandicum), an antidiabetic medicinal plant of the Eastern James Bay Cree pharmacopeia.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhododendron groenlandicum (Oeder) Kron & Judd (Labrador tea) was identified as an antidiabetic plant through an ethnobotanical study carried out with the close collaboration of Cree nations of northern Quebec in Canada. OBJECTIVES: In a previous study the plant showed glitazone-like activity in a 3T3-L1 adipogenesis bioassay. The current study sought to identify the active compounds responsible for this potential antidiabetic activity using bioassay guided fractionation based upon an in vitro assay that measures the increase of triglycerides content in 3T3-L1 adipocyte. MATERIALS AND METHODS: Isolation and identification of the crude extract's active constituents was carried out. The 80% ethanol extract was fractionated using silica gel column chromatography. Preparative HPLC was then used to isolate the constituents. The identity of the isolated compounds was confirmed by UV and mass spectrometry. RESULTS: Nine chemically distinct fractions were obtained and the adipogenic activity was found in fraction 5 (RGE-5). Quercetins, (+)-catechin and (-)-epicatechin were detected and isolated from this fraction. While (+)-catechin and (-)-epicatechin stimulated adipogenesis (238±26% and 187±21% relative to vehicle control respectively) at concentrations equivalent to their concentrations in the active fraction RGE-5, none afforded biological activity similar to RGE-5 or the plant's crude extract when used alone. When cells were incubated with a mixture of the two compounds, the adipogenic activity was close to that of the crude extract (280.7±27.8 vs 311± 30%). CONCLUSION: Results demonstrate that the mixture of (+)-catechin and (-)-epicatechin is responsible for the adipogenic activity of Labrador tea. This brings further evidence for the antidiabetic potential of R. groenlandicum and provides new opportunities to profile active principles in biological fluids or in traditional preparations.

Adipogenic Activity of Wild Populations of Rhododendron groenlandicum, a Medicinal Shrub from the James Bay Cree Traditional Pharmacopeia.

The traditional medicinal plant, Labrador tea (Rhododendron groenlandicum (Oeder) Kron & Judd; Ericaceae), present in the pharmacopoeia of the Cree of Eeyou Istchee, has shown glitazone-like activity in the 3T3-L1 adipogenesis bioassay. This activity has been attributed to phenolic compounds, which have been shown to vary in this plant as a function of insolation parameters. The goal of this study was to determine if these changes in phenolic content were pharmacologically significant. Leaves were harvested in 2006 throughout the James Bay region of Northern Quebec and ethanol extracts were tested in vitro using the 3T3-L1 murine cell line adipogenesis bioassay. This traditional medicinal plant was found active in the assay. However, there was no detectable spatial pattern in the accumulation of intracellular triglycerides, suggesting that such patterns previously observed in the phenolic profile of Labrador tea were not pharmacologically significant. Nonetheless, a reduction in the adipogenic activity was observed and associated with higher concentrations of quercetin for which selected environmental variables did not appropriately explain its variation.

Novel Approach to Identify Potential Bioactive Plant Metabolites: Pharmacological and Metabolomics Analyses of Ethanol and Hot Water Extracts of Several Canadian Medicinal Plants of the Cree of Eeyou Istchee.

We evaluated and compared the antidiabetic potential and molecular mechanisms of 17 Cree plants' ethanol extracts (EE) and hot water extracts (HWE) on glucose homeostasis in vitro and used metabolomics to seek links with the content of specific phytochemicals. Several EE of medical plants stimulated muscle glucose uptake and inhibited hepatic G6Pase activity. Some HWE partially or completely lost these antidiabetic activities in comparison to EE. Only R. groenlandicum retained similar potential between EE and HWE in both assays. In C2C12 muscle cells, EE of R. groenlandicum, A. incana and S. purpurea stimulated glucose uptake by activating AMP-activated protein kinase (AMPK) pathway and increasing glucose transporter type 4 (GLUT4) expression. In comparison to EE, HWE of R. groenlandicum exhibited similar activities; HWE of A. incana completely lost its effect on all parameters; interestingly, HWE of S. purpurea activated insulin pathway instead of AMPK pathway to increase glucose uptake. In the liver, for a subset of 5 plants, HWE and EE activated AMPK pathway whereas the EE and HWE of S. purpurea and K. angustifolia also activated insulin pathways. Quercetin-3-O-galactoside and quercetin 3-O-α-L-arabinopyranoside, were successfully identified by discriminant analysis as biomarkers of HWE plant extracts that stimulate glucose uptake in vitro. More importantly, the latter compound was not identified by previous bioassay-guided fractionation.

Lingonberry (Vaccinium vitis-idaea L.) Exhibits Antidiabetic Activities in a Mouse Model of Diet-Induced Obesity.

Vaccinium vitis-idaea, commonly known as lingonberry, has been identified among species used by the Cree of Eeyou Istchee of northern Quebec to treat symptoms of diabetes. In a previous study, the ethanol extract of berries of V. vitis-idaea enhanced glucose uptake in C2C12 muscle cells via stimulation of AMP-activated protein kinase (AMPK) pathway. The purpose of this study was to examine the effect of plant extract in a dietary mouse model of mild type 2 diabetes. C57BL/6 mice fed a high-fat diet (HFD, ∼35% lipids) for 8 weeks that become obese and insulin-resistant (diet-induced obesity, DIO) were used. Treatment began by adding V. vitis-idaea extract to HFD at 3 different concentrations (125, 250, and 500 mg/Kg) for a subsequent period of 8 weeks (total HFD, 16 weeks). The plant extract significantly decreased glycemia and strongly tended to decrease insulin levels in this model. This was correlated with a significant increase in GLUT4 content and activation of the AMPK and Akt pathways in skeletal muscle. V. vitis-idaea treatment also improved hepatic steatosis by decreasing hepatic triglyceride levels and significantly activated liver AMPK and Akt pathways. The results of the present study confirm that V. vitis-idaea represents a culturally relevant treatment option for Cree diabetics and pave the way to clinical studies.

The action of antidiabetic plants of the canadian james bay cree traditional pharmacopeia on key enzymes of hepatic glucose homeostasis.

We determined the capacity of putative antidiabetic plants used by the Eastern James Bay Cree (Canada) to modulate key enzymes of gluconeogenesis and glycogen synthesis and key regulating kinases. Glucose-6-phosphatase (G6Pase) and glycogen synthase (GS) activities were assessed in cultured hepatocytes treated with crude extracts of seventeen plant species. Phosphorylation of AMP-dependent protein kinase (AMPK), Akt, and Glycogen synthase kinase-3 (GSK-3) were probed by Western blot. Seven of the seventeen plant extracts significantly decreased G6Pase activity, Abies balsamea and Picea glauca, exerting an effect similar to insulin. This action involved both Akt and AMPK phosphorylation. On the other hand, several plant extracts activated GS, Larix laricina and A. balsamea, far exceeding the action of insulin. We also found a significant correlation between GS stimulation and GSK-3 phosphorylation induced by plant extract treatments. In summary, three Cree plants stand out for marked effects on hepatic glucose homeostasis. P. glauca affects glucose production whereas L. laricina rather acts on glucose storage. However, A. balsamea has the most promising profile, simultaneously and powerfully reducing G6Pase and stimulating GS. Our studies thus confirm that the reduction of hepatic glucose production likely contributes to the therapeutic potential of several antidiabetic Cree traditional medicines.

Populus balsamifera Extract and Its Active Component Salicortin Reduce Obesity and Attenuate Insulin Resistance in a Diet-Induced Obese Mouse Model.

Populus balsamifera L. (BP) is a medicinal plant stemming from the traditional pharmacopoeia of the Cree of Eeyou Istchee (CEI-Northern Quebec). In vitro screening studies revealed that it strongly inhibited adipogenesis in 3T3-L1 adipocytes, suggesting potential antiobesity activity. Salicortin was identified, through bioassay-guided fractionation, as the active component responsible for BP's activity. The present study aimed to assess the potential of BP and salicortin at reducing obesity and features of the metabolic syndrome, in diet-induced obese C57Bl/6 mice. Mice were subjected to high fat diet (HFD) for sixteen weeks, with BP (125 or 250 mg/kg) or salicortin (12.5 mg/kg) introduced in the HFD for the last eight of the sixteen weeks. BP and salicortin effectively reduced whole body and retroperitoneal fat pad weights, as well as hepatic triglyceride accumulation. Glycemia, insulinemia, leptin, and adiponectin levels were also improved. This was accompanied by a small yet significant reduction in food intake in animals treated with BP. BP and salicortin (slightly) also modulated key components in signaling pathways involved with glucose regulation and lipid oxidation in the liver, muscle, and adipose tissue. These results confirm the validity of the CEI pharmacopoeia as alternative and complementary antiobesity and antidiabetic therapies.

Larix laricina, an Antidiabetic Alternative Treatment from the Cree of Northern Quebec Pharmacopoeia, Decreases Glycemia and Improves Insulin Sensitivity In Vivo.

Larix laricina K. Koch is a medicinal plant belonging to traditional pharmacopoeia of the Cree of Eeyou Istchee (Eastern James Bay area of Canada). In vitro screening studies revealed that, like metformin and rosiglitazone, it increases glucose uptake and adipogenesis, activates AMPK, and uncouples mitochondrial function. The objective of this study was to evaluate the antidiabetic and antiobesity potential of L. laricina in diet-induced obese (DIO) C57BL/6 mice. Mice were subjected for eight or sixteen weeks to a high fat diet (HFD) or HFD to which L. laricina was incorporated at 125 and 250 mg/kg either at onset (prevention study) or in the last 8 of the 16 weeks of administration of the HFD (treatment study). L. laricina effectively decreased glycemia levels, improved insulin resistance, and slightly decreased abdominal fat pad and body weights. This occurred in conjunction with increased energy expenditure as demonstrated by elevated skin temperature in the prevention study and improved mitochondrial function and ATP synthesis in the treatment protocol. L. laricina is thus a promising alternative and complementary therapeutic approach for the treatment and care of obesity and diabetes among the Cree.

Antidiabetic compounds from Sarracenia purpurea used traditionally by the Eeyou Istchee Cree First Nation.

Through ethnobotanical surveys, the CIHR Team in Aboriginal Antidiabetic Medicines identified 17 boreal forest plants stemming from the pharmacopeia of the Cree First Nations of Eeyou Istchee (James Bay region of Northern Quebec) that were used traditionally against diabetes symptoms. The leaves of Sarracenia purpurea (pitcher plant), one of the identified Cree plants, exhibited marked antidiabetic activity in vitro by stimulating glucose uptake in C2C12 mouse muscle cells and by reducing glucose production in H4IIE rat liver cells. Fractionation guided by glucose uptake in C2C12 cells resulted in the isolation of 11 compounds from this plant extract, including a new phenolic glycoside, flavonoid glycosides, and iridoids. Compounds 6 (isorhamnetin-3-O-glucoside), 8 [kaempferol-3-O-(6″-caffeoylglucoside], and 11 (quercetin-3-O-galactoside) potentiated glucose uptake in vitro, which suggests they represent active principles of S. purpurea (EC(50) values of 18.5, 13.8, and 60.5 µM, respectively). This is the first report of potentiation of glucose uptake by compounds 6 and 8, while compound 11 (isolated from Vaccinium vitis) was previously shown to enhance glucose uptake. Treatment of H4IIE liver cells with the new compound 1, 6'-O-caffeoylgoodyeroside, decreased hepatic glucose production by reducing glucose-6-phosphatase enzymatic activity (IC(50) = 13.6 µM), which would contribute to lowering glycemia and to the antidiabetic potential of S. purpurea.

Adipogenic constituents from the bark of Larix laricina du Roi (K. Koch; Pinaceae), an important medicinal plant used traditionally by the Cree of Eeyou Istchee (Quebec, Canada) for the treatment of type 2 diabetes symptoms.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetes is a growing epidemic worldwide, especially among indigenous populations. Larix laricina was identified through an ethnobotanical survey as a traditional medicine used by Healers and Elders of the Cree of Eeyou Istchee of northern Quebec to treat symptoms of diabetes and subsequent in vitro screening confirmed its potential. MATERIALS AND METHODS: We used a bioassay-guided fractionation approach to isolate the active principles responsible for the adipogenic activity of the organic extract (80% EtOH) of the bark of Larix laricina. Post-confluent 3T3-L1 cells were differentiated in the presence or absence of the crude extract, fractions or isolates of Larix laricina for 7 days, then triglycerides content was measured using AdipoRed reagent. RESULTS: We identified a new cycloartane triterpene (compound 1), which strongly enhanced adipogenesis in 3T3-L1 cells with an EC(50) of 7.7 µM. It is responsible for two thirds of the activity of the active fraction of Larix laricina. The structure of compound 1 was established on the basis of spectroscopic methods (IR, HREIMS, 1D and 2D NMR) as 23-oxo-3α-hydroxycycloart-24-en-26-oic acid. We also identified several known compounds, including three labdane-type diterpenes (compounds 2-4), two tetrahydrofuran-type lignans (compounds 5-6), three stilbenes (compounds 7-9), and taxifolin (compound 10). Compound 2 (13-epitorulosol) also potentiated adipogenesis (EC(50) 8.2 µM) and this is the first report of a biological activity for this compound. CONCLUSIONS: This is the first report of putative antidiabetic principles isolated from Larix laricina, therefore increasing the interest in medicinal plants from the Cree pharmacopeia.

Populus balsamifera L. (Salicaceae) mitigates the development of obesity and improves insulin sensitivity in a diet-induced obese mouse model.

ETHNOBOTANICAL RELEVANCE: : In previous in vitro bioassay studies, Populus balsamifera L. (Salicaceae), a medicinal plant ethnobotanically identified from the traditional pharmacopoeia of the Cree of Eeyou Istchee (Eastern James Bay area of Canada), exhibited a strong anti-obesity potential by potently inhibiting adipogenesis in 3T3-L1 adipocytes. The aim of the study is to evaluate the effectiveness of this plant extract in mitigating the development of obesity and the metabolic syndrome in diet-induced obese (DIO) C57BL/6 mice. MATERIALS AND METHODS: Mice were subjected for eight weeks to a standard diet (CHOW), a high fat diet (HFD; DIO group), or HFD to which Populus balsamifera was incorporated at 125 and 250 mg/kg. RESULTS: The results showed that Populus balsamifera decreased in a dose-dependent manner the weight gain of whole body, retroperitoneal fat pad and liver as compared to DIO controls and reduced the severity of hepatic macrovesicular steatosis and triglyceride accumulation. This plant extract also decreased glycemia in the second half of the feeding period and improved insulin sensitivity by diminishing insulin levels and the leptin/adiponectin ratio, as well as augmenting adiponectin levels. These effects were associated with slightly but significantly reduced food intake with 250 mg/kg Populus balsamifera as well as with an increase in energy expenditure (increase in skin temperature and increased expression of uncoupling protein-1; UCP-1). Data also suggest other mechanisms, such as inhibition of adipocyte differentiation, decrease of hepatic inflammatory state and potential increase in hepatic fatty acid oxidation. CONCLUSION: Taken together, these results confirm the potential of Populus balsamifera as a culturally adapted therapeutic approach for the care and treatment of obesity and diabetes among the Cree.

Comprehensive evidence-based assessment and prioritization of potential antidiabetic medicinal plants: a case study from canadian eastern james bay cree traditional medicine.

Canadian Aboriginals, like others globally, suffer from disproportionately high rates of diabetes. A comprehensive evidence-based approach was therefore developed to study potential antidiabetic medicinal plants stemming from Canadian Aboriginal Traditional Medicine to provide culturally adapted complementary and alternative treatment options. Key elements of pathophysiology of diabetes and of related contemporary drug therapy are presented to highlight relevant cellular and molecular targets for medicinal plants. Potential antidiabetic plants were identified using a novel ethnobotanical method based on a set of diabetes symptoms. The most promising species were screened for primary (glucose-lowering) and secondary (toxicity, drug interactions, complications) antidiabetic activity by using a comprehensive platform of in vitro cell-based and cell-free bioassays. The most active species were studied further for their mechanism of action and their active principles identified though bioassay-guided fractionation. Biological activity of key species was confirmed in animal models of diabetes. These in vitro and in vivo findings are the basis for evidence-based prioritization of antidiabetic plants. In parallel, plants were also prioritized by Cree Elders and healers according to their Traditional Medicine paradigm. This case study highlights the convergence of modern science and Traditional Medicine while providing a model that can be adapted to other Aboriginal realities worldwide.

EGF mediates protection against Fas-induced apoptosis by depleting and oxidizing intracellular GSH stocks.

Several pieces of evidence have demonstrated the importance of reduction/oxidation (redox) signaling in biological processes, including sensitivity toward apoptosis. In parallel, it was recently reported that growth factors induce the generation of reactive oxygen species (ROS). Therefore, we tested the hypothesis that the anti-apoptotic effect of epidermal growth factor (EGF) was mediated by changes in the redox state of hepatocytes through changes in GSH stocks. Isolated mouse hepatocytes were cultured and exposed to anti-Fas stimulation in order to induce apoptosis. Cell death by apoptosis was assessed by Hoechst 33258 staining and by measuring caspase-3 proteolysis activity. Cell treatment with EGF significantly decreased total (GSx) and reduced (GSH) glutathione levels in the presence and the absence of anti-Fas. Furthermore, glutathione reductase activity was lower in EGF-treated cultures (by 28%) as compared to untreated cultures which lead to a significant decline in GSH/GSx ratio. These effects were found to be EGF-receptor tyrosine kinase activity dependent. Co-stimulation of cells with anti-Fas and EGF attenuated caspase-3 activation and cell death by apoptosis by 70%. GSH monoethylester (GSHmee) significantly attenuated the effect of EGF on GSH and GSH/GSx ratio. It caused an increase in caspase-3 activation and in the percentage of apoptotic cells in anti-Fas + EGF-treated cells, thus resulting in a 53% decline in the protective effect of EGF. In conclusion, EGF induces a significant and specific depletion and oxidization of intracellular GSH, paralleled by a protection against Fas-induced apoptosis. GSH repenishment partly counteracted these effects suggesting that GSH depletion contributed to the protective effect of EGF against caspase-3 activation and cell death by apoptosis.

Antiapoptotic effect of EGF on mouse hepatocytes associated with downregulation of proapoptotic Bid protein.

Growth factors have been shown to protect cells from a variety of apoptotic stimuli. In the liver, the Fas system is thought to be very important in the genesis of hepatocyte apoptosis. Others have already shown the importance of the phosphatidylinositol 3-kinase (PI3-kinase) pathway and of increased Bcl-xl expression in the antiapoptotic effect of growth factors on hepatocytes. We investigated the effect of EGF on Bid, a BH3-only member of the Bcl-2 family and a major player in the transduction of the Fas apoptotic signal. Hepatocyte apoptosis was induced in vitro with a purified anti-mouse Fas antibody. The effect of EGF on Bid protein expression was studied on those cultures. EGF dose dependently reduced the expression of Bid protein in primary mouse hepatocyte cultures independently of Fas stimulation. This decrease was not the result of the degradation of Bid into its active p15 fragment. Treating cells with a specific inhibitor of the EGF receptor autophosphorylation completely abolished the decrease in Bid expression afforded by EGF. Treatment with LY-294002, a PI3-kinase blocker, partly reverted the effect of EGF. When apoptosis was induced in Bid-deficient hepatocytes, EGF lost its capacity to protect cells against this type of cell death. These results show that EGF decreases the expression of Bid protein and suggest that the effect of EGF on Bid is one of the mechanisms of the antiapoptotic effect of EGF.

Resistance to Fas-induced apoptosis in hepatocytes: role of GSH depletion by cell isolation and culture.

The involvement of reduction/oxidation (redox) state in cell sensitivity to apoptosis has been suggested by several studies in which induction of apoptosis was shown to require oxidative stress or GSH extrusion. On the other hand, biochemical studies of caspases revealed that their activation necessitates a reduced cysteine in their active site. This is ensured by maintaining intact intracellular glutathione status during apoptotic induction as reported by in vivo studies. Therefore, we investigated the relationship between intracellular glutathione levels and the sensitivity of mouse hepatocytes in culture to Fas-induced apoptosis as well as potential mechanisms responsible for this sensitivity. We found that total and reduced glutathione levels are decreased by one-half after cell isolation procedure and further decline by 25% during cell culture for 2 h in normal Williams' E medium. Cell culture in medium supplemented with cysteine and methionine maintains glutathione at a level similar to that measured just after cell isolation. Results show that the capacity of Fas to activate caspase-8 and to induce apoptosis requires important intracellular glutathione levels and high GSH/total glutathione ratio. In conclusion, the present study shows that intracellular glutathione plays an important role in maintaining the apoptotic machinery functional and is thus capable of transmitting the apoptotic signal.