EGF-receptor phosphorylation and downstream signaling are activated by genistein during subacute liver damage.

The epidermal growth factor receptor (EGFR) plays an important role on hepatic protection in acute and chronic liver injury. The aim of this study was to investigate the role of genistein on EGFR expression, phosphorylation and signaling pathways in experimental subacute liver damage induced by carbon tetrachloride (CCl4). We used male Wistar rats that were randomly divided into four groups: (1) Control; (2) Genistein 5 mg/kg per oral; (3) Subacute liver damage induced by CCl4 4 mg/kg subcutaneously; and (4) Animals received CCl4 and genistein at the dosage indicated. The effect of genistein on EGFR expression, phosphorylation and signaling pathways were investigated by western blot and densitometric analyses. Histological changes were evaluated on slices stained with Hematoxylin-Eosin and Masson´s trichromic, as well as an immunohistochemical analysis for proliferating cell nuclear antigen (PCNA). Additionally, pro-inflammatory cytokines and liver enzymes were quantified. Our study showed that genistein increased EGFR expression, EGFR-specific tyrosine residues phosphorylation (pY1068-EGFR and pY84-EGFR), signal transducer and activator of transcription phosphorylation (pSTAT5), protein kinase B phosphorylation (pAKT) and PCNA in animals with CCl4-induced subacute liver damage. It was found a significant reduction of pro-inflammatory cytokines in serum from animals with subacute liver damage treated with genistein. Those effects were reflected in an improvement in the architecture and liver function. In conclusion, genistein can induce a transactivation of EGFR leading to downstream cell signaling pathways as early events associated with regeneration and hepatoprotection following subacute liver damage.

ß-Hydroxyphosphocarnitine modifies fibrosis, steatosis and improves liver function in non-alcoholic steatohepatitis induced in rats.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is a chronic disease characterized by inflammation, steatosis, and liver fibrosis. The liver is particularly affected by alterations in lipid metabolism. Our aim was to evaluate the effect of ß-hydroxyphosphocarnitine (ß-HPC) on NASH induced in rats. METHODS: NASH was produced via the ad libitum daily chronic administration of a fructose solution (400 kcal) for 9 weeks, an oral dose of fat solution (16 kcal) for 7 weeks and a subcutaneous injection of CCl4 (30%) two times a week for 2 weeks to Wistar rats. To evaluate the effect of ß-HPC, a dose of 100 mg/kg was administered perorally for 4 weeks and its biochemical and hepatic effects on rats with NASH were analyzed. Serum levels of glucose, triglycerides, cholesterol, and liver enzymes were quantified. Histological changes were evaluated on slices stained with H&E, trichromic and PAS. Glycogen content was measured in liver samples. α-SMA and SREBP-1 immunopositive cells were identified in liver tissue. RESULTS: NASH was characterized by elevated triglycerides, elevated liver damage enzymes, and the presence of necrosis, inflammation, steatosis, and fibrosis. Significant amounts of glycogen were found, along with α-SMA positive cells in fibrosis areas. The over-expression of SREBP-1 in cytoplasm and nuclei was evident. Animals with NASH treated with ß-HPC showed a significant reduction in inflammation, necrosis, and glycogen content in the liver. A reduction in α-SMA and SREBP-1 immunopositive cells correlated with a significant reduction in the degree of fibrosis and steatosis found in liver tissue. ß-HPC reduced the levels of ALP and GGT, and significantly reduced triglyceride levels. Animals treated with ß-HPC did not show any alterations in liver enzyme function. CONCLUSIONS: Our research shows that ß-HPC can improve liver function and morphology in the case of NASH induced in rats, suggesting ß-HPC could be potentially used in the treatment of NASH.

Polyene Antibiotics Physical Chemistry and Their Effect on Lipid Membranes; Impacting Biological Processes and Medical Applications.

This review examined a collection of studies regarding the molecular properties of some polyene antibiotic molecules as well as their properties in solution and in particular environmental conditions. We also looked into the proposed mechanism of action of polyenes, where membrane properties play a crucial role. Given the interest in polyene antibiotics as therapeutic agents, we looked into alternative ways of reducing their collateral toxicity, including semi-synthesis of derivatives and new formulations. We follow with studies on the role of membrane structure and, finally, recent developments regarding the most important clinical applications of these compounds.

Preclinical safety evaluation of amphotericin A21: A novel antifungal.

Safety studies are essential in drug development. This study evaluates the safety of Amphotericin A21 (AmB-A21), a derivative of amphotericin B with antifungal therapeutic potential. We performed a chronic toxicity study, a targeted organ study and a dermal irritation test. To evaluate chronic toxicity, 18 male adult rats were treated orally with AmB-21 (2 mg/kg) for 26 weeks. The effects on body-weight and animal health were measured, and haematological, clinical chemistry and histopathological tests were conducted on various organs. In the target organ toxicity study, male adult rats received a daily oral dose of AmB-21 (2 mg/kg) for 6 and 17 weeks; testicle histology and testosterone levels were then evaluated. For the dermal irritation study, AmB-21 (200 and 1000 mg/kg) was placed on the skin of adult male rabbits; macroscopic and microscopic studies, as well as haematological and clinical chemistry tests were then conducted. The chronic toxicity study revealed that AmB-21 caused testicle damage, and the testicle-targeted study showed structural alterations and changes in testosterone levels at 17 weeks. However, these alterations were no longer observed 8 weeks after discontinuation of treatment, and the testes showed very similar characteristics to those in the control group. The dermal irritation study showed skin thickening and reddening in rabbits treated with 2000 mg of AmB-A21 after 14 days of exposure. This same group also showed changes in liver enzymes, renal parameters and platelet levels. Based on our results, we consider AmB-21 to be a potential candidate for safe, long-term antifungal treatment given its reduced side effects.

An Amphotericin B Derivative Equally Potent to Amphotericin B and with Increased Safety.

Amphotericin B is the most potent antimycotic known to date. However due to its large collateral toxicity, its use, although long standing, had been limited. Many attempts have been made to produce derivatives with reduced collateral damage. The molecular mechanism of polyene has also been closely studied for this purpose and understanding it would contribute to the development of safe derivatives. Our study examined polyene action, including chemical synthesis, electrophysiology, pharmacology, toxicology and molecular dynamics. The results were used to support a novel Amphotericin B derivative with increased selectivity: L-histidine methyl ester of Amphotericin B. We found that this derivative has the same form of action as Amphotericin B, i.e. pore formation in the cell membrane. Its reduced dimerization in solution, when compared to Amphotericin B, is at least partially responsible for its increased selectivity. Here we also present the results of preclinical tests, which show that the derivative is just as potent as Amphotericin B and has increased safety.

Synthesis, characterization and biocompatibility of cadmium sulfide nanoparticles capped with dextrin for in vivo and in vitro imaging application.

BACKGROUND: The safe use in biomedicine of semiconductor nanoparticles, also known as quantum dots (QDs), requires a detailed understanding of the biocompatibility and toxicity of QDs in human beings. The biological characteristics and physicochemical properties of QDs entail new challenges regarding the management of potential adverse health effects following exposure. At certain concentrations, the synthesis of semiconductor nanoparticles of CdS using dextrin as capping agent, at certain concentration, to reduce their toxicity and improves their biocompatibility. RESULTS: This study successfully synthesized and characterized biocompatible dextrin-coated cadmium sulfide nanoparticles (CdS-Dx/QDs). The results show that CdS-Dx/QDs are cytotoxic at high concentrations (>2 µg/mL) in HepG2 and HEK293 cells. At low concentrations (<1 µg/mL), CdS-Dx/QDs were not toxic to HepG2 or HeLa cells. CdS-Dx nanoparticles only induced cell death by apoptosis in HEK293 cells at 1 µg/mL concentrations. The in vitro results showed that the cells efficiently took up the CdS-Dx/QDs and this resulted in strong fluorescence. The subcellular localization of CdS-Dx/QDs were usually small and apparently unique in the cytoplasm in HeLa cells but, in the case of HEK293 cells it were more abundant and found in cytoplasm and the nucleus. Animals treated with 100 µg/kg of CdS-Dx/QDs and sacrificed at 3, 7 and 18 h showed a differential distribution in their organs. Intense fluorescence was detected in lung and kidney, with moderate fluorescence detected in liver, spleen and brain. The biocompatibility and toxicity of CdS-Dx/QDs in animals treated daily with 100 µg/kg for 1 week showed the highest level of fluorescence in kidney, liver and brain. Less fluorescence was detected in lung and spleen. There was also evident presence of fluorescence in testis. The histopathological and biochemical analyses showed that CdS-Dx/QDs were non-toxic for rodents. CONCLUSIONS: The in vitro and in vivo studies confirmed the effective cellular uptake and even distribution pattern of CdS-Dx/QDs in tissues. CdS-Dx/QDs were biocompatible with tissues from rodents. The CdS-Dx/QDs used in this study can be potentially used in bio-imaging applications.

Immuno-modulator metallo-Peptide reduces inflammatory state in obese zucker fa/fa rats.

Metabolic syndrome is a prothrombotic and proinflammatory chronic state. In obesity, the adipose tissue secretes various adipokines that take part in a variety of physiological and pathophysiological processes, including immunity and inflammation. Previous studies using a liver damage model treated with the immune-modulator metallo-peptide (IMMP) showed lessening in the degree of inflammation. Therefore, this study was set up to evaluate the anti-inflammatory effect of IMMP in obese Zucker fa/fa rats. We used Zucker-Lepr fa/fa and Zucker-Lean in this protocol. The groups received IMMP 50 ng/kg by i.p., three times per week for 8 weeks. Blood samples were collected by cardiac puncture and the serum was preserved at -80°C until analysis; the liver was excised and preserved in formaldehyde 4%. Analyses were performed to determine cytokine, insulin, glucose, triglyceride and cholesterol levels in serum, and histological analysis was also performed. IMMP treatment of obese rats resulted in decreased levels of proinflammatory cytokines (leptin, lL-6, IL-1betha, INF-gamma) and a chemokine (MCP-1), and increased levels of anti-inflammatory adipokine (adiponectin). In addition, treatment decreased the damage and hepatic steatosis generated in the tissue of obese rats. The IMMP exerted an anti-inflammatory effect in obese rats and therefore may be an effective and safe therapeutic alternative in the treatment of metabolic syndrome.

Pharmacokinetic and pharmacological effects of ß-hydroxyphosphocarnitine in animal models.

The purpose of this research was to describe the pharmacokinetic parameters of ß-hydroxyphosphocarnitine (ß-HPC; CAS No. 1220955-20-3) after a single oral dose in rats and rabbits as well as to assess the impact of 14 weeks of ß-HPC (100 mg/kg) treatment on the serum metabolites and liver enzymes, body weight, and hepatic steatosis of lean and obese Zucker fa/fa rats. In the case of the rat and rabbit study, the ß-HPC area under the curve, biological half-life, and clearance were 2,174.4 versus 3,128 µg ∙ h/ml, 23.7 versus 8.87 h, and 13.9 versus 151.1 ml/h in the rats versus the rabbits, respectively. The values for the time of maximal concentration were 0.58 versus 1.53 h, for the maximal concentration, they were 62.4 versus 221.4 µg/ml, and for the absorption rate constant 0.02 versus 2.40 h(-1), respectively. In the case of the Zucker fa/fa rat study, ß-HPC administered orally once a day reduced insulin, triglyceride, and cholesterol levels in the liver and serum; it also reduced weight gain and decreased liver steatosis in obese rats after 14 weeks. ß-HPC could therefore potentially be used in the treatment of metabolic syndrome.

Pharmacological evaluation of a ß-hydroxyphosphonate analogue of l-carnitine in obese Zucker fa/fa rats.

In this study, we evaluated the effect of an analogue of l-carnitine on parameters involved with Metabolic Syndrome in obese Zucker rats. Twenty-four rats were treated for 5 weeks with l-carnitine (300 mg/kg) and its analogue at two concentrations (100 and 250 mg/kg) to assess their impact on glucose, triglycerides and cholesterol in liver and blood samples, as well as the amount of liver glycogen. Liver slices were also analysed. The analogue reduced the levels of glucose, triglycerides and cholesterol in liver and the level of triglycerides in serum. At 100 mg/kg, the analogue proved more effective than l-carnitine in improving the biochemical alterations present in liver. The amount of liver glycogen content was higher in obese animals treated with both l-carnitine and the analogue. No changes on insulin and leptin were observed in animals treated. l-carnitine and its analogue reduced the microvesicular fatty infiltration in liver. This study demonstrated that the analogue tested is more potent and efficient than l-carnitine and improves the pharmacological profile of l-carnitine.

Synthesis, characterization and toxicological evaluation of maltodextrin capped cadmium sulfide nanoparticles in human cell lines and chicken embryos.

BACKGROUND: Semiconductor Quantum dots (QDs) have become quite popular thanks to their properties and wide use in biological and biomedical studies. However, these same properties entail new challenges in understanding, predicting, and managing potential adverse health effects following exposure. Cadmium and selenium, which are the major components of the majority of quantum dots, are known to be acutely and chronically toxic to cells and organisms. Protecting the core of nanoparticles can, to some degree, control the toxicity related to cadmium and selenium leakage. RESULTS: This study successfully synthesized and characterized maltodextrin coated cadmium sulfide semiconductor nanoparticles. The results show that CdS-MD nanoparticles are cytotoxic and embryotoxic. CdS-MD nanoparticles in low concentrations (4.92 and 6.56 nM) lightly increased the number of HepG2 cell. A reduction in MDA-MB-231 cells was observed with concentrations higher than 4.92 nM in a dose response manner, while Caco-2 cells showed an important increase starting at 1.64 nM. CdS-MD nanoparticles induced cell death by apoptosis and necrosis in MDA-MD-231 cells starting at 8.20 nM concentrations in a dose response manner. The exposure of these cells to 11.48-14.76 nM of CdS-MD nanoparticles induced ROS production. The analysis of cell proliferation in MDA-MB-231 showed different effects. Low concentrations (1.64 nM) increased cell proliferation (6%) at 7 days (p < 0.05). However, higher concentrations (>4.92 nM) increased cell proliferation in a dose response manner (15-30%) at 7 days. Exposures of chicken embryos to CdS-MD nanoparticles resulted in a dose-dependent increase in anomalies that, starting at 9.84 nM, centered on the heart, central nervous system, placodes, neural tube and somites. No toxic alterations were observed with concentrations of < 3.28 nM, neither in cells nor chicken embryos. CONCLUSIONS: Our results indicate that CdS-MD nanoparticles induce cell death and alter cell proliferation in human cell lines at concentrations higher than 4.92 nM. We also demonstrated that they are embryotoxic. However, no toxic effects were observed with doses lower than 3.28 nM in neither cells nor chicken embryos. The CdS-MD nanoparticles used in this study can be potentially used in bio-imaging applications. However, further studies using mammalian species are required in order to discard more toxic effects.

Ethanol-induced oxidative stress is associated with EGF receptor phosphorylation in MCF-10A cells overexpressing CYP2E1.

Breast cancer is the most common cancer and the second leading cause of cancer-related mortality worldwide. The etiology of breast cancer is very diverse and ethanol (EtOH) consumption is a well-established risk factor for breast cancer in women. However, the mechanism by which EtOH exerts its carcinogenic activity in breast tissue remains unknown. CYP2E1 is known to metabolize ethanol and produce reactive oxygen species (ROS), including superoxide in epithelial cells. Therefore, in the present studies, we investigated whether there is an increase in ROS following overexpression of CYP2E1 in MCF-10A cells. We found that 30 and 100 mM EtOH increased ROS levels after 2 h treatment in CYP2E1 overexpressing cells. Based on these results and our previous studies with ROS-producing chemicals, we also examined epidermal growth factor receptor (EGFR) activation following exposure to ethanol. We found that there was an increase in phosphorylation of pY1086 EGFR after 18 h EtOH treatment in CYP2E1 overexpressing cells. These studies support a hypothesis that EtOH might increase human mammary cell activation, via an EGFR-dependent signaling mechanism associated with oxidative stress.

Danazol improves thrombocytopenia in HCV patients treated with peginterferon and ribavirin.

BACKGROUND: Thrombocytopenia is a common hematologic disorder observed in patients with chronic hepatitis C virus (HCV) infection. Combined peginterferon (PEG-INF) and ribavirin treatment may exacerbate thrombocytopenia in patients with HCV. OBJECTIVE: The aim of this pilot clinical trial was to assess the efficacy, tolerability and safety of Danazol in thrombocytopenia associated with PEG-INF and ribavirin treatment in patients with HCV. MATERIAL AND METHODS: We included patients whose platelets were < 90,000/mm³ and who were undergoing antiviral treatment. Danazol (300-600 mg/day) was administered during and until the end of antiviral therapy [7.6 months (2 to 11 months)]. The monitoring was performed through platelet analysis and liver function tests. A viral load test was done at the beginning and end of treatment. Fortynine patients receiving a combined therapy of PEG-INF, ribavirin and Danazol increased their platelet levels to 121,081/mm³ (46,000-216,000/mm³); 10.6% of patients gained > 100,000 platelets/mm³, and 71% of patients maintained their initial platelet levels. Sustained viral response (SVR) was achieved in 63% of patients. SVR rates were high in patients with genotype non 1 (78.7%) and decreased in patients with genotype 1 (60.1%). The increase in platelet levels was associated to an increase in fibrinogen levels and a decrease in the activity of ALT. By contrast, patients without SVR presented a delayed response to increased platelet levels and showed no significant improvement in liver function when they received Danazol. CONCLUSION: Danazol can be used along with PEG-INF and ribavirin to treat thrombocytopenia in patients with HCV.

Protective effect of thymic humoral factor on porcine serum-induced hepatic fibrosis and liver damage in Wistar rats.

INTRODUCTION: Immunomodulatory drugs have been reported to have anti-inflammatory and anti-fibrotic properties. Thymic humoral factor (THF), a peptide produced in the thymus, causes a potent immunomodulatory effect on different components of the immune system. OBJECTIVE: To evaluate the effect of THF on different stages of liver damage and fibrosis induced in rats through the administration of porcine serum (PS). MATERIAL AND METHODS: PS-induced liver fibrosis models serve as a primarily immunological mechanism in the development of liver damage and fibrosis. RESULTS: The intraperitoneal administration of THF in rats with PS-induced liver damage produced a reduction of ALT and AST after 60 days. Histopathological changes in liver sections showed an improved histological appearance and lower % of fibrosis after 60 days in liver damaged rats that received THF treatment. Serum IL-6 levels were visibly reduced by THF administration after 60 days and in comparison with rats that did not receive the treatment. This was due to an increment in serum IL-10 levels caused by the administration of THF, which appears to reduce the inflammatory process by decreasing immune response. CONCLUSION: THF had beneficial effects in combating liver damage and fibrosis processes in an autoimmune model of PS-induced liver fibrosis in rats.

Efficacy and safety of two analogs of L-carnitine on rats made insulin resistant by a high-fructose diet.

AIM: To evaluate the efficacy and safety of 2 analogs of L-carnitine on rats made insulin resistant by a high-fructose diet. METHODS: Using rats made insulin resistant by a high-fructose diet, we investigated the impact of 2 analogs of L-carnitine (25 mg/kg) and L-carnitine (250 mg/kg) on glucose, triglycerides and cholesterol blood levels, and liver glycogen. We also evaluated the safety of both analogs by the assessment of some biochemical and hematological parameters, a histological analysis and a study of embryotoxicity. RESULTS: Both analogs reduced the levels of triglycerides in the liver and plasma, but only analog 2 reduced the cholesterol levels in insulin-resistant rats. No changes were observed in glycogen content. Safety evaluations revealed alterations in blood lymphocytes and embryotoxicity data. CONCLUSION: This study demonstrated that the 2 analogs maintain the pharmacological properties of L-carnitine but have a different efficacy, potency and toxicity.

Use of a graft of demineralized bone matrix along with TGF-ß1 leads to an early bone repair in dogs.

Tibia fractures are common in small animal practice. Over the past decade, improvements to animal internal fracture fixation have been developed. TGF-ß1 has been shown to be crucial in the development, induction and repair of bone. In present study, we investigate the effect of local application of a graft demineralized bone matrix (DBM) along with TGF-ß1 in a model of open osteotomy induced experimentally in dogs. Tibia fracture was brought about by using an open osteotomy model in young male dogs. Fracture repair was evaluated by a histological and biochemical analysis. Collagen content, proteolytic activity and urokinase-type plasminogen activator (uPA) expression were analyzed at the end of the study. Radiographic analysis, alkaline phosphatase and hematological evaluation were performed weekly. At the fifth week, there was an improvement and restoration of bone architecture in animals treated with a graft containing TGF-ß1 (5 ng/ml) compared with the control and graft groups, as was evidenced by the presence of an early formation of wide callus and bone regeneration. In addition, local application of TGF-ß1 led to an increase in collagen and proteolytic activity. More immunopositive osteoclast and mesenchymal cells were found in bone tissue from animals treated with TGF-ß1 as compared with the control group. No changes in alkaline phosphatase, hematological and clinical parameters were observed. This study shows that the combined use of DBM along with TGF-ß1 is able to improve and accelerate the bone repair.

Potential risks resulting from fruit/vegetable-drug interactions: effects on drug-metabolizing enzymes and drug transporters.

It has been well established that complex mixtures of phytochemicals in fruits and vegetables can be beneficial for human health. Moreover, it is becoming increasingly apparent that phytochemicals can influence the pharmacological activity of drugs by modifying their absorption characteristics through interactions with drug transporters as well as drug-metabolizing enzyme systems. Such effects are more likely to occur in the intestine and liver, where high concentrations of phytochemicals may occur. Alterations in cytochrome P450 and other enzyme activities may influence the fate of drugs subject to extensive first-pass metabolism. Although numerous studies of nutrient-drug interactions have been published and systematic reviews and meta-analyses of these studies are available, no generalizations on the effect of nutrient-drug interactions on drug bioavailability are currently available. Several publications have highlighted the unintended consequences of the combined use of nutrients and drugs. Many phytochemicals have been shown to have pharmacokinetic interactions with drugs. The present review is limited to commonly consumed fruits and vegetables with significant beneficial effects as nutrients and components in folk medicine. Here, we discuss the phytochemistry and pharmacokinetic interactions of the following fruit and vegetables: grapefruit, orange, tangerine, grapes, cranberry, pomegranate, mango, guava, black raspberry, black mulberry, apple, broccoli, cauliflower, watercress, spinach, tomato, carrot, and avocado. We conclude that our knowledge of the potential risk of nutrient-drug interactions is still limited. Therefore, efforts to elucidate potential risks resulting from food-drug interactions should be intensified in order to prevent undesired and harmful clinical consequences.

Mutagenicity and safety evaluation of water extract of Coriander sativum leaves.

Coriander has been used as a spice and medicinal plant for centuries. Several studies have described its biological properties and some reports have indicated its pharmacological actions in some human pathology. However, data on its toxicity and metabolism are limited or null, and no research has been conducted with mammalian cells. The purpose of this study was to evaluate the mutagenicity and safety of Coriandrum sativum extract. The mutagenic effects of C. sativum extract were evaluated by Ames test. Mutagenicity was present when the C. sativum extract was used in high concentrations in both tested strains (Salmonella typhimurium TA97 and TA102). Our research showed that C. sativum extract reduced the cell survival of human cell lines (WRL-68 and 293Q cells) by inducing apoptosis and necrosis in the cases where extract concentration was the highest. The C. sativum extract altered the cell cycle; it increased the G1 phase of hepatic cells and reduced the G2+M phase in both cell lines in a dose-response manner. These results showed correlation with a reduction in the mitotic index. The extract also induced severe malformations during embryonic development. Exposure of chicken embryos to the C. sativum extract resulted in a dose-dependent increase of anomalies. Present results show that C. sativum extract reduced the axial skeleton and affected the neural tube, the somites, the cardiovascular structures, and the eye. According to the present results, the C. sativum aqueous extract cannot be considered safe. These results indicate that some significant adverse effects of C. sativum extract could be observed in vivo.

EGF-receptor phosphorylation and downstream signaling are activated by benzo[a]pyrene 3,6-quinone and benzo[a]pyrene 1,6-quinone in human mammary epithelial cells.

Benzo[a]pyrene (BaP) is activated by xenobiotic-metabolizing enzymes to highly mutagenic and carcinogenic metabolites. Previous studies in this laboratory have shown that benzo[a]pyrene quinones (BPQs), 1,6-BPQ and 3,6-BPQ, are able to induce epidermal growth factor receptor (EGFR) cell signaling through the production of reactive oxygen species. Recently, we have reported that BPQs have the potential to induce the expression of genes involved in numerous pathways associated with cell proliferation and survival in human mammary epithelial cells. In the present study we demonstrated that BPQs not only induced EGFR tyrosine autophosphorylation, but also induced EGFR-dependent tyrosine phosphorylation of phospholipase C-gamma1 and several signal transducers and activators of transcription (STATs). The effects of BPQs were evaluated in a model of EGF withdrawal in MCF10-A cells. We found that BPQs (1 muM), induced EGFR tyrosine phosphorylation at positions Y845, Y992, Y1068, and Y1086. PLC-gamma1 phosphorylation correlated with the phosphorylation of tyrosine-Y992, a proposed docking site for PLC-gamma1 on the EGFR. Additionally, we found that BPQs induced the activation of STAT-1, STAT-3, STAT-5a and STAT-5b. STAT5 was shown to translocate to the nucleus following 3,6-BPQ and 1,6-BPQ exposures. Although the patterns of phosphorylation at EGFR, PLC-gamma1 and STATs were quite similar to those induced by EGF, an important difference between BPQ-mediated signaling of the EGFR was observed. Signaling produced by EGF ligand produced a rapid disappearance of EGFR from the cell surface, whereas BPQ signaling maintained EGFR receptors on the cell membrane. Thus, the results of these studies show that 1,6-BPQ and 3,6-BPQ can produce early events as evidenced by EGFR expression, and a prolonged transactivation of EGFR leading to downstream cell signaling pathways.

Risks and benefits of commonly used herbal medicines in Mexico.

In Mexico, local empirical knowledge about medicinal properties of plants is the basis for their use as home remedies. It is generally accepted by many people in Mexico and elsewhere in the world that beneficial medicinal effects can be obtained by ingesting plant products. In this review, we focus on the potential pharmacologic bases for herbal plant efficacy, but we also raise concerns about the safety of these agents, which have not been fully assessed. Although numerous randomized clinical trials of herbal medicines have been published and systematic reviews and meta-analyses of these studies are available, generalizations about the efficacy and safety of herbal medicines are clearly not possible. Recent publications have also highlighted the unintended consequences of herbal product use, including morbidity and mortality. It has been found that many phytochemicals have pharmacokinetic or pharmacodynamic interactions with drugs. The present review is limited to some herbal medicines that are native or cultivated in Mexico and that have significant use. We discuss the cultural uses, phytochemistry, pharmacological, and toxicological properties of the following plant species: nopal (Opuntia ficus), peppermint (Mentha piperita), chaparral (Larrea divaricata), dandlion (Taraxacum officinale), mullein (Verbascum densiflorum), chamomile (Matricaria recutita), nettle or stinging nettle (Urtica dioica), passionflower (Passiflora incarnata), linden flower (Tilia europea), and aloe (Aloe vera). We conclude that our knowledge of the therapeutic benefits and risks of some herbal medicines used in Mexico is still limited and efforts to elucidate them should be intensified.

Genistein modifies liver fibrosis and improves liver function by inducing uPA expression and proteolytic activity in CCl4-treated rats.

AIM: To evaluate the effect of genistein on the fibrosis and matrix degradation caused by experimentally induced fibrosis in rats. METHODS: Hepatic fibrosis was brought about by chronic administration of carbon tetrachloride to rats. To evaluate the effect of genistein on liver fibrosis and function, total collagen content and proteolytic activity in the liver were quantified. Urokinase-type plasminogen activator (uPA) expression during experimental fibrosis was localized by immunohistochemistry. Histopathological changes were evaluated using light and electron microscopy. RESULTS: Animals with fibrosis and treated with genistein showed an important reduction (73%) in hepatic collagen content as well as an improvement in liver function (p < 0.001). Genistein increased the capacity of the liver to degrade type I collagen and Matrigel (3.1- and 3.7-fold, respectively; p < 0.001) in animals with liver fibrosis. Genistein increased the number of uPA-immunoreactive cells. The increase in the uPA expression correlated with an increase in proteolytic activity. Histological analysis revealed a reduction in the number of fiber septa in pericentral and perisinusoidal areas. Transmission electron micrographs of livers from animals with fibrosis and treated with genistein showed a reduction in the number of hepatic stellate cells activated and a smaller number of collagen fibers. CONCLUSION: Genistein is able to improve the liver after injury and fibrosis induced by chronic administration of carbon tetrachloride. This finding suggests that genistein has antifibrogenic potential and could therefore be useful for treating chronic liver disease.