The impact of the application of compochar on soil moisture, stress, yield and nutritional properties of legumes under drought stress.

Nowadays, when climate change is becoming more and more evident, drought stress plays a very important role, including in agriculture. The increasing number of years with extreme temperatures in the Czech Republic has a negative impact on agricultural production, among other things. Therefore, ways are being sought to reduce these negative impacts. One of them may be the use of compochar (a mixture of compost and biochar) to improve water retention in the soil. The effect of compochar addition on soil properties and crop yield was tested under conditions simulating severe drought stress (greenhouse experiments) compared to normal conditions (field experiments). The aim was to find the most suitable ratio of compochar addition that would reduce the negative effects of drought stress on the yield and quality of peas and beans. Tested soil was only able to retain water between 0.03 and 0.18 cm3/cm3, while the compochar itself retained between 0.12 and 0.32 cm3 cm-3. Three substrate variants were tested by varying the amount of compochar (10, 30 and 50 % v/v) in the soil, and all three substrates showed a similar water content between 0.03 and 0.21 cm3 cm-3 depending on the planted crop and week of cultivation. No apparent stress was observed in crops planted in 100 % compochar. Nevertheless, in general, the trend of chlorophyll a/b ratio increased with increasing amounts of compochar in the soil, indicating stress. Yield increased by approximately 50 % for both test crops when 30 % compochar was used as substrate. The flavonoid content in beans was between 410 and 500 µg CE g-1 DW and in peas was approximately 300 µg CE g-1 DW. The results showed that the utilization of compochar had no effect on either total phenol content, flavonoid content or antioxidant capacity. The combination of compochar with soil (30 %) was found to positively affect the (i) soil moisture, (ii) crop yield, and (iii) nutritional properties of peas and beans and (iv) the ability of plants to withstand drought stress.

Biological analyses of the effects of TiO2 and PEG-b-PLA nanoparticles on three-dimensional spheroid-based tumor.

The aim of our study was to monitor the antiproliferative/ cytotoxic and genotoxic effects of both, poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) and titanium dioxide (TiO2) nanoparticles on the tumor (HT-29, MCF-7, U118MG) and healthy (HEK-293T) cell lines during 2D cultivation and during cultivation in the spheroid form (3D cultivation). Cells or spheroids were cultivated with nanoparticles (0.01, 0.1, 1, 10, 50, and 100 ?g/ml) for 72 hours. The cytotoxic effect was determined by the MTT test and the genotoxic effect by the comet assay. We found that 2D cultivation of tumor cell lines with PEG-b-PLA and TiO2 nanoparticles had an anti-proliferative effect on human colon cancer cell line HT-29, human breast cancer cell line MCF-7, human glioma cell line U-118MG during 72h cultivation, but not on control/healthy HEK-293T cells. At the concentrations used, the tested nanoparticles caused no cytotoxic effect on tumor cell lines. Nanoparticles PEG-b-PLA induced significant damage to DNA in HT-29 and MCF-7 cells, while TiO2 nanoparticles in MCF-7 and U-118MG cells. Only PEG-b-PLA nanoparticles caused cytotoxic (IC50 = 7 mikrog/ml) and genotoxic effects on the healthy cell line HEK-293T after 72h cultivation. The cells which were cultivated in spheroid forms were more sensitive to both types of nanoparticles. After 72h cultivation, we observed the cytotoxic effect on both, the tumor and healthy cell lines.

Health safety of parabens evaluated by selected in vitro methods.

Seven selected parabens (4 allowed, 3 banned in cosmetics) were tested in order to confirm and expand historical data on their toxicological properties and safety. The aim was to apply novel in vitro methods, which have been sufficiently technically and scientifically validated for the purposes of toxicological testing of chemicals. The study included several toxicological endpoints such as skin/eye irritation, skin sensitization, endocrine disruption and genotoxicity. The battery of selected methods comprised regulatory accepted EpiDerm™ skin model (OECD TG 439); EpiOcular™ corneal model (OECD TG 492) and scientifically valid test method HET-CAM (DB-ALM Protocol No. 47); in chemico test DPRA (OECD TG 442C); in vitro test LuSens (OECD TG 442D) and in vitro test h-CLAT (OECD TG 442E); Ames MPF™ (Xenometrix) and XenoScreen YES/YAS (Xenometrix). Overall, none of the 4 allowed parabens exhibited skin/eye irritation or genotoxicity. However, all allowed parabens in cosmetics were predicted as samples with potentially sensitizing properties in the LuSens and h-CLAT test methods, but not confirmed by DPRA. Endocrine disruption was recorded only at high concentrations, whereas methyl paraben and ethyl paraben exhibited the lowest activity. This study confirmed the safety of use of the allowed parabens in the highest recommended concentrations in cosmetics or pharmaceuticals.

Iodine, thyroglobulin and thyroid gland.

Iodine is essential in the biosynthesis of thyroid hormones that affect metabolic processes in the organism from the prenatal state to the elderly. The immediate indicator of iodine intake is the concentration of iodine in urine, but the indicator of iodine intake in the longer term of several months is thyroglobulin (Tg). Tg negatively correlated with increasing intake of iodine in population that do not suffer from thyroid disease, while a more than adequate to excessive iodine intake leads to an increase in Tg. The dependence of Tg on iodine can be described by a U-shaped curve. Thyroglobulin in serum is elevated in thyroid disease mainly in hyperthyroidism (diagnosis E05 of WHO ICD-10 codes) and in goiter (diagnosis E04 of WHO ICD-10 codes). Tg values decrease below 20 microg/l after effective treatment of patients with thyroid disease. Thyroglobulin may thus be an indicator of thyroid stabilization and the success of the thyroid gland treatment.

Familial hypocalciuric hypercalcemia in an index male: grey zones of the differential diagnosis from primary hyperparathyroidism in a 13-year clinical follow up.

Familial hypocalciuric hypercalcemia (FHH) type 1, caused by a heterozygous inactivating mutation of the gene encoding the calcium-sensing receptor (CaSR), is characterized by mild to moderate hypercalcemia, hypocalciuria and inappropriately normal or elevated parathyroid hormone (PTH). FHH must be differentiated from primary hyperparathyroidism (PHPT) because parathyroidectomy is ineffective in the former. Herein, we report a 39-year-old male patient with a 13-year history of asymptomatic PTH-dependent hypercalcemia (mean calcium of 2.88 mmol/l; reference range 2.15-2.55 mmol/l) and calcium-to-creatinine clearance ratio (Ca/Cr) ranging from 0.007 to 0.0198, which is consistent with either FHH or PHPT. Although a family history of hypercalcemia was negative, and PET-CT with fluorocholine was suggestive of a parathyroid adenoma, genetic analysis of the CaSR gene identified a heterozygous inactivating mutation NM_000388.4:c.1670G>A p. (Gly557Glu) in exon 6 and a polymorphism NM_000388.4:c.1192G>A p. (Asp398Asn) in exon 4. The G557E mutation has been previously reported in a Japanese family in which all family members with the mutation had Ca/Cr below 0.01 consistent with FHH. The biochemical profile of FHH and PHPT may overlap. Our FHH patient with a G557E CaSR mutation illustrates that the differential diagnosis can be difficult in an index case with no family history, (false) positive parathyroid imaging and higher calciuria than expected for FHH. Calcium intake, vitamin D status and bone resorption might have contributed to the Ca/Cr variations over a 13-year clinical follow up. This case thus emphasizes the irreplaceable role of genetic testing of the CaSR gene when clinical evaluation is inconclusive.

Safety testing of adult novelties using in vitro methods.

Despite widespread and prolonged use of adult novelties, their health safety is not regularly tested or legally regulated. In the EU, adult novelties are subjected to the General Product Safety Directive, placing the burden of proof regarding safe products onto the manufacturers. The aim of our pilot study was to expand knowledge on potential application of in vitro methods for hazard prediction of extracts from final products. We subjected extracts of 20 adult novelties, purchased on the Czech market to toxicological tests including NRU cytotoxicity assay, sensitization tests DPRA and LuSens and the YES/YAS endocrine assay. Four samples produced cytotoxicity. Sensitization potential was recorded by DPRA (three samples) while the LuSens reported ten samples. Regarding endocrine disruption, three samples produced antiestrogen and antiandrogen effects. Six samples exhibited androgenic potential and one sample showed estrogenic potential. Positive results with possible health effects were recorded repeatedly for samples made of ABS, PVC and latex. The study has confirmed promising usefulness of our test methods combination with regard to safety testing of this type of consumer products. The results should be evaluated with care, however, the data bring added-value to the limited knowledge of mixture toxicology and are indicative for further testing.

Comparison of methods used for evaluation of mutagenicity/genotoxicity of model chemicals - parabens.

Growing worldwide efforts to replace (reduce) animal testing and to improve alternative in vitro tests which may be more efficient in terms of both time, cost and scientific validity include also genotoxicity/mutagenicity endpoints. The aim of the review article was to summarize currently available in vitro testing approaches in this field, their regulatory acceptance and recommended combinations for classification of chemicals. A study using the combination of Comet Assay performed on two cell lines and the Chromosomal Aberration test on human peripheral lymphocytes was performed with the aim to predict the genotoxic potential of selected paraben esters, serving as a model chemical group. Parabens are widely used in consumer products as preservatives and have been reported to exhibit inconclusive results in numerous genotoxicity studies. The Comet Assay identified Ethylparaben and Benzylparaben as potentially genotoxic. The Chromosomal Aberration test revealed weak genotoxic potential in case of Ethylparaben and positive genotoxicity in case of Butylparaben, Propylparaben and Isopropylparaben. The main reasons for variability seem to be limited water solubility of parabens, determining their bioavailability at the cellular level, and absence of metabolic activation in the Comet Assay. The results confirmed that the Comet Assay should serve as a screening test and should not be used as a stand-alone method for classification of genotoxicity. The weight of evidence approach in risk assessment should be supported with data generated with the use of human relevant in vitro methods based on cells / tissues of human origin.

Effect of natural polyphenols on thromboxane levels in children with Crohn's disease.

OBJECTIVES: The aim of this study was to investigate the relationship between thromboxane levels and oxidative stress in children with Crohn´s disease (CD), and examine the effect of natural polyphenolic compounds on thromboxane levels. METHODS: This study involved 14 children suffering from CD and 15 healthy controls. Patients were receiving the polyphenolic extract Pycnogenol for 10 weeks. Plasma levels of the static and dynamic forms of thromboxane B2 as well as their metabolite 11-dehydro thromboxane B2 in urine were determined. RESULTS: In comparison to controls, CD patients had significantly higher levels of the static and dynamic forms of thromboxane B2. Pycnogenol decreased the level of the dynamic form of thromboxane B2 after 10 weeks of administration. CONCLUSIONS: Paediatric Crohn's disease is associated with higher thromboxane levels. Our results indicate that Pycnogenol administration reduces thromboxane levels, which may positively influence some clinical symptoms of CD such as thromboembolic episodes (Tab. 3, Ref. 49).

Genes and Mechanisms Responsible for Expansion of Acute Myeloid Leukaemia Blasts.

Acute myeloid leukaemia (AML) is the leading form of fatal acute leukaemia in adults. AML is a heterogeneous disease with respect to responsible mutations and chromosomal abnormalities as well as to their clinicopathological image. In recent years, great progress has been made in techniques allowing detection of genetic changes in both de novo AML and in secondary AML induced by other haematological disorders or therapy, and in detection of residual disease after therapy. Accumulated knowledge allowed better understanding of the molecules and mechanisms involved not only in the formation and expansion of a primary leukaemia-founding clone, but also of a temporal order of changes leading to the fully malignant phenotype. The recent knowledge of bone marrow (BM) compartments and interrelations among various BM resident and recruited cell types helps in understanding the AML development. The progress in the techniques and knowledge will result in the development and use of molecularly targeted therapies tailored to individual patient needs.

Role of oxidative stress, adiponectin and endoglin in the pathophysiology of erectile dysfunction in diabetic and non-diabetic men.

Erectile dysfunction (ED) and diabetes mellitus (DM) share common pathophysiological risk factors including endothelial dysfunction which together with hyperglycemia contribute to the increased oxidative/glycooxidative stress. A reduced NO concentration is insufficient for relaxation processes in the penis. Chronic inflammation and endoglin are involved in the regulation of endothelial function. Adiponectin from the adipose tissue has anti-inflammatory effects. Our study aimed to investigate the relation between erectile function in patients with and without DM and the oxidative stress, hormone adiponectin, and endothelial dysfunction marker endoglin. Men (n=32) with ED evaluated by the International Index of Erectile function (IIEF-5) questionnaire (17 without DM (NDM); 15 with type 2 diabetes mellitus (DM)) and 31 controls were included. Advanced glycation end products (AGEs), 8-isoprostanes (8-isoP), protein carbonyls, antioxidant capacity, adiponectin and endoglin were determined in the blood. DM patients compared to NDM patients and controls, had increased levels of glucose, C-reactive protein, triacylglycerols, 8-isoP, AGEs, endoglin and BMI. IIEF-5 score, NO and adiponectin levels were decreased. We are the first to find out that endoglin shows a negative correlation with erectile function in NDM, but not in DM patients. Endoglin can be considered as endothelial dysfunction marker in nondiabetic men suffering from ED.

Calcineurin role in porcine oocyte activation.

Calcineurin is required for oocyte exit from meiotic block in metaphase II (MII) stage in invertebrates and also in lower vertebrates. However, the role of calcineurin in mammalian oocyte activation is still unclear. The aim of this study was to determine whether calcineurin is involved in the processes regulating porcine oocyte activation. Indirect immunofluorescence demonstrated localization of both calcineurin subunits, CnA and CnB, especially in the cortex area of MII oocytes, in vitro fertilized and also parthenogenetically activated oocytes. After activation, the fluorescence intensity of the protein in the cortex area of oocytes remains unchanged; the protein calcineurin in the cytoplasm was recorded mainly around the pronuclei. Treatment of matured oocytes with calcineurin inhibitors, cyclosporin A (CsA) and hymenistatin I (HS-I), followed by activation with calcium ionophore A23187, significantly decreased the rate of activated oocytes compared to oocytes that were treated only with calcium ionophore (Ca-Io), (CsA+Ca-Io 25.0% v. Ca-Io 83.3%; HS-I+Ca-Io 32.5% v. Ca-Io 85.0%). Compared to the control, CsA treatment of matured oocytes followed by activation with Ca-Io did not affect the activity level of metaphase-promoting factor (MPF) and mitogen-activated protein kinase (MAPK) in activated oocytes evaluated by kinase activity assay. Simultaneous staining of calcineurin and cortical granule content in matured oocytes showed that calcineurin distributed in the cortical area of the oocyte has not been colocalized with cortical granules content. On the other hand, the calcineurin inhibition before parthenogenetic activation leads to a reduction of the cortical reaction level compared to oocytes that were not treated with CsA (complete exocytosis: CsA+Ca-Io 2.6% v. Ca-Io 83.9%; sum of cortical granule brightness: CsA + Ca-Io 0.69 v. Ca-Io 0.15). Our results showed that calcineurin is involved in the process of pig oocyte activation and cortical granule exocytosis; however this regulation seems to be MPF and MAPK independent.

The association between lipid parameters and obesity in university students.

BACKGROUND: Abdominal obesity is associated with high plasma triglyceride and with low plasma high-density lipoprotein cholesterol levels. AIM AND METHODS: Objective of the study was to find an association between plasma lipid and lipoprotein levels and anthropometric parameters in abdominal obesity in Slovakian university students. Lipid profile and anthropometric parameters of obesity were studied in a sample of 419 probands, including 137 men and 282 women. RESULTS: Males had higher values of non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and very low-density lipoprotein cholesterol (VLDL-C) than females, but these differences were not significant. Females had significantly (P < 0.05) higher TC and HDL-C (P < 0.001) than males. In comparison, all anthropometric parameters in the males were significantly (P < 0.001) higher than in the females. A positive correlation between non-HDL-C, TG, VLDL-C and anthropometric parameters (BMI, WC, WHR, WHtR) was found at P < 0.001. LDL was positively correlated with BMI, WCF, WHtR and TC with BMI, WHtR at P < 0.001. We also observed a correlation between TC-WCF and LDL-WHR at P < 0.01. A negative correlation was found between HDL and all monitored anthropometric parameters at P < 0.001. On the other hand, no correlation between TC and WHR was detected. CONCLUSION: This study shows an association between plasma lipid and lipoprotein levels and anthropometric parameters in abdominal obesity in young people, predominantly university students.

Prognostic and predictive molecular biological markers in prostate cancer - significance of expression of genes PCA3 and TMPRSS2.

UNLABELLED: Prostate specific antigen and digital rectal examination have low specificity for detecting prostate cancer and they poorly predict the presence of aggressive disease. We present recent findings on PCA3 and TMPRSS:ERG fusion and assessed the relationship between PSA, urine PCA3 and TMPRSS2:ERG and corelation with pathological findings. We tested the PCA3 score in two groups. The first comprised 96 men treated in urology out-patient units with suspicion of prostate cancer, who had elevated PSA and/or positive DRE. The second group comprised 28 patients, who were treated by radiation for localised prostate cancer, and whose PCA3 was regularly monitored. A further cohort comprised patients with already-diagnosed tumors, who had undergone radical prostatectomy. With these, using histopathological samples, we examined samples of the TMPRSS2:ERG fusion gene and compared the results with Gleason score values and level of PSA. We also examined the TMPRSS2:ERG gene in patients who had positive biopsy. Part of the genetical analysis was also an examination of the MSMB gene.The sensitivity of PCA3 testing was 66.7% and the specificity 78.5%. TMPRSS2:ERG gene was correllated with the Gleason score. Neither the TMPRSS2:ERG (p=0.13) nor the MSMB (p=0.556) genotype had an influence on the value of the Gleason score. However a difference was found between the homozygote and wild type (WT) in the TMPRSS2 gene.FISH analysis of TMPRSS/ERG gene fusion was evaluated as positive in 8 (36.8%) of the biopsically verified tumors and in 20 (37.3%) of the evaluated patients after RAPE of parafin slicing.We did not confirm a corellation between fusion and Gleason score (p=0.29).PCA3, with its higher sensitivity in comparison with PSA, is more useful for eventual screening examination. Identification of further molecular markers such as TMPRSS2, may be very promising ways to determine further prognosis of patients with prostate cancer. KEYWORDS: prostate cancer, PSA, PCA3.

Effect of natural polyphenols (Pycnogenol) on oxidative stress markers in children suffering from Crohn's disease--a pilot study.

Crohn's disease (CD) is a nonspecific, chronic inflammatory disease of the gastrointestinal tract. It is supposed that in etiopathogenesis oxidative stress (OS) plays a role. However, its precise role in the active and non-active states of disease is not known yet. We conducted a pilot study focusing on the relationship between OS of CD in remission and the possibility to influence clinical parameters and markers of OS by polyphenolic extract, Pycnogenol® (Pyc). Compared to 15 healthy controls 15 pediatric CD patients (all were in remission according to their disease activity index - PCDAI) had reduced the activity of Cu/Zn-superoxide dismutase (SOD) and increased the oxidative damage to proteins. We found negative correlations between markers of inflammation (calprotectin, CRP) as well as between PCDAI and total antioxidant capacity (TAC). Activities of antioxidant enzymes, SOD, and glutathione peroxidase (GPX) negatively correlated with calprotectin and PCDAI. Pyc (2 mg/kg) positively influenced the parameters of OS in CD patients after 10 weeks of administration.

DNA released by leukemic cells contributes to the disruption of the bone marrow microenvironment.

Reciprocal interactions between a tumor and its microenvironment control expansion of tumor cells. Here we show a specific type of interaction in which blasts of experimental leukemia destroy the bone marrow (BM) structures and kill stromal cells. The in vitro experiments showed that the cytotoxic agent released by leukemic cells is the fragmented DNA derived from their genome and occurring in nucleosome-like complexes. This DNA entered nuclei of BM or other cells and induced H2A.X phosphorylation at serine 139, similar to double-strand break-inducing agents. There was a correlation between large amounts of acquired DNA and death of recipient cells. Moreover, the DNA integrated into chromosomal DNA of recipient cells. Primary human acute myeloid leukemia cells also released fragmented DNA that penetrated the nuclei of other cells both in vitro and in vivo. We suggest that DNA fragments released from leukemic and also perhaps other types of tumor cells can activate DNA repair mechanisms or death in recipient cells of a tumor microenvironment, depending on the amount of the acquired DNA. This can impair DNA stability and viability of tumor stromal cells, undermine homeostatic capacity of tumor microenvironment and facilitate tumor progression.

Prevalence of obesity and metabolic syndrome in adult population of selected regions of the Czech Republic. Relation to eating habits and smoking.

Prevalence of the metabolic syndrome is around 25% in Europe but its occurrence grows in both genders with increasing age and weight. Lifestyle factors may contribute to the risk of developing metabolic syndrome. The objective of this study was to determine the relationship between metabolic syndrome and eating habits as well as length of sleep and smoking. Participants (519 women and 286 men aged 18-65 years) were chosen by random selection and questioned about their eating habits, sleep length and smoking. This information was combined with anthropometric and clinical parameters of metabolic syndrome. The female group was divided into two subgroups depending on climacteric stage (before and after menopause). Metabolic syndrome prevalence does not differ between regions in neither female (29.9%) nor male (32.5%) group. Body mass index ≥25 was detected in 50.4% of all women and 65.7% of men; 23.5% of all women and 21.7% men had body mass index ≥30. In conclusion, metabolic syndrome prevalence was proved to depend on eating habits and family heredity. Positive correlation between the above mentioned factors demonstrated itself in the total sample but not in individual regions. Metabolic syndrome prevalence in Czech adults is comparable with neighbouring countries. No significant interregional differences in metabolic syndrome prevalence within the Czech Republic were detected. In conclusion, relationship between eating habits and metabolic syndrome was confirmed.

Relative expression of γδ T-cell receptor gene families detected by RT-PCR and capillary electrophoresis.

γδ T cells are intensively studied because their function in infection, allergy, autoimmune disease, cancer and post-transplant period is not yet fully understood. PCR-based techniques were established to study the γ variable (Vγ) and δ variable (Vδ) gene families. PCR product evaluation is routinely carried out by Southern blot analysis or the third complementarity-determining region spectratyping, but a fast and simple assessment of Vγ and Vδ gene family expression is missing. The aim of our study was to test capillary electrophoresis as a potential method for evaluating the composition of the γδ T-cell population. This report provides optimized PCR conditions for γδ T-cell receptor amplification. Further, it describes the utilization of capillary electrophoresis in the Agilent 2100 Bioanalyzer to evaluate the relative expression of Vγ and Vδ gene families after their amplification. An application of the methodology to peripheral blood mononuclear cell samples from patients during haemato-oncological treatment is shown. The described methodology is fast and simple to operate and is therefore suitable as a first screening of the γδ T-cell population composition in tissues of interest.

Identification and characterisation of pro-metastatic targets, pathways and molecular complexes using a toolbox of proteomic technologies.

BACKGROUND: Cancer metastasis involves changes in signalling pathways, cell adhesion, migration and invasiveness. Modern proteomic, mass spectrometry based techniques enable discovery of new pro-metastatic proteins and their functional partners. Also, they might be involved in their functional characterisation and validation towards development of new diagnostic and therapeutic approaches. AIM: The aim of this communication is to describe current possibilities for proteomic techniques in the discovery and characterization of pro-metastatic targets. The NF-kappaB pathway is one of the players responsible for a number of pro-metastatic processes. The related proteins can be discovered using untargeted proteomic approaches by comparing proteomes with different metastatic potential. Stable isotope labelling based methods enable a parallel analysis of more tumour samples. The identified pro-metastatic proteins can be characterised in relationship to cell migration, invasiveness and proliferation and in terms of their involvement in molecular complexes via protein-protein interactions. Advantages of the metabolic labelling based methods can be taken in these studies, the same applies for characterisation of related surface proteins involved in cell adhesion, invasiveness and cell-to-cell communication. For clinical validation of pro-metastatic proteins in large sample cohorts, approaches of targeted proteomics based on selected reaction monitoring are becoming methods of choice. CONCLUSION: Current proteomics methods play an important role in the identification of novel pro-metastatic proteins, pathways and molecular complexes, in their functional characterisation and validation towards diagnostic and therapeutic application.

[Adrenergic regulation of the mammalian heart]. / Adrenergní regulace srdecní cinnosti savcu.

Adrenergic system in the mammalian heart plays a pivotal role in regulation of contractility and/or heart rate. At present, nine subtypes of adrenergic receptors (AR) have been identified. Among these there are six AR localized in the plasma membrane of cardiomyocytes. They mediate their effects by increases in the intracellular level of various signaling molecules which initiate diverse cellular responses. The effects of stimulation of both beta-AR by catecholamines noradrenaline and adrenaline are consistent with coupling to the Gs protein-adenylyl cyclase-cAMP-protein kinase classical pathway, with consequent protein kinase A-catalysed phosphorylation of target enzymes responsible for increased contractility and hastening of relaxation. In contrast to beta1-AR, beta2-AR can also couple to G(i) protein which causes cAMP-independent control of calcium signaling and contraction. Activation of beta-AR obviously couples to a G(i)/ nitric oxide pathway and mediates a decrease in contractile force, whereas stimulation of alpha-AR increases contractility via G protein/phospholipase C/diacylglycerol/inositoltrisphosphate/protein kinase C pathway. These findings reveal the diversity and specifity of AR subtypes and G protein interactions. They also provide new insights in understanding the differential regulation and functionality of AR subtypes in healthy and diseased hearts.

How does pycnogenol® influence oxidative damage to DNA and its repair ability in elderly people?

Our purpose in this randomized, double blind, placebo controlled study was to find out the possible effect of a polyphenolic pine bark extract, Pycnogenol® (Pyc) on the level of 8-oxo-7,8-dihydroguanine (8-oxoG) as representative of oxidative damage to DNA and on the DNA repair ability of elderly people. According to our results, three months of Pyc administration had no effect on the level of oxidative damage to DNA or on repair ability, but we found a relationship between the level of 8-oxoG and repair ability of DNA in this group. To conclude, even if the positive effect of Pyc was not confirmed in the case of elderly people it is important to highlight the necessity of further investigations about the mechanisms of Pyc acting on different age groups.