A chemical-ecology approach has been used to screen plants growing in Guyana Highlands as an indicator of production of biologically active secondary metabolites. Extracts of leaves from 19 species, most of them endemic in this area, and collected at the top of Roraima Tepui (2,723 m) were screened in vitro at different concentrations for their potential cytotoxic activity against three tumour cell lines: HT29 (colon), A549 (lung) and MDA-MB-231 (breast). MTT (tetrazolium blue) colorimetric assay was employed as cytotoxicity test. Extracts of nine species caused less than 30% growth in at least one cell line. From these species, high cytotoxic activity was detected in Casearia sylvestris var. lingua and Ledotamnus sessiliflorus extracts; medium activity was found in Cyathea sp. Two other species, Cyrilla racemiflora and Heliamphora minor showed lower but significant cytotoxicity. Further cytotoxicity-directed fractionation of these extracts would be advisable to isolate and identify the active principles of these plants.
Cytotoxicity ; Aspects of disease screening ; Cell Line ; MB-2 ; Employed

This study aimed to investigate the effect and underlying mechanism of Poria cocos polysaccharides(PCP) on myocardial cell apoptosis in the rat model of myocardial ischemia-reperfusion injury(MI/RI). Male SPF-grade SD rats were randomly divided into a sham group(saline), a model group(saline), low-and high-dose PCP groups(100 and 200 mg·kg~(-1)), and a fasudil group(10 mg·kg~(-1)), with 16 rats in each group. Except for the sham group, the other four groups underwent left anterior descending coronary artery ligation for 30 min followed by reperfusion for 2 h to establish the MI/RI model. The myocardial infarct area was assessed by TTC staining. Histological changes were observed through HE staining. Myocardial cell apoptosis was evaluated using TUNEL staining. Serum lactate dehydrogenase(LDH), creatine kinase MB(CK-MB), interleukin-1β(IL-1β) and IL-18 levels, myocardial superoxide dismutase(SOD) activity and malondialdehyde(MDA) levels were detected by ELISA. Protein expression of B-cell lymphoma 2(Bcl-2), Bcl-2 associated X protein(Bax), cleaved caspase-3, Ras homolog gene A(RhoA), myosin phosphatase target subunit 1(MYPT-1), phosphorylated MYPT-1(p-MYPT-1), and Rho-associated coiled-coil forming kinase 1(ROCK 1) were measured by Western blot. Pathological staining of myocardial tissue revealed that in the model group, there was focal necrosis of myocardial tissue, myocardial cell swelling, unclear boundaries, and neutrophil infiltration. These pathological changes were alleviated in the low-and high-dose PCP groups and the fasudil group. Compared with the model group, the low-and high-dose PCP groups and the fasudil group showed significantly reduced myocardial infarct area and myocardial cell apoptosis rate. Compared with the sham group, the model group exhibited elevated serum LDH, CK-MB, IL-1β and IL-18 levels, increased MDA levels, relative protein expression of Bax, cleaved caspase-3, RhoA, ROCK1 and p-MYPT-1, and decreased myocardial SOD levels and Bcl-2 protein expression. Compared with the model group, the PCP groups and the fasudil group showed lowered serum LDH, CK-MB, IL-1β and IL-18 levels, decreased MDA levels, relative protein expression of Bax, cleaved caspase-3, RhoA, ROCK1 and p-MYPT-1, and increased myocardial SOD levels and Bcl-2 protein expression. PCP exhibited a certain preventive effect on myocardial tissue pathological damage and myocardial cell apoptosis in MI/RI rats, possibly related to the inhibition of the Rho-ROCK signaling pathway activation, thereby reducing oxidative stress and inflammatory responses.
Rats ; Male ; Animals ; Myocardial Reperfusion Injury/drug therapy* ; bcl-2-Associated X Protein/metabolism* ; Rats, Sprague-Dawley ; Caspase 3/metabolism* ; Interleukin-18 ; Wolfiporia ; Signal Transduction ; Myocardial Infarction/drug therapy* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Creatine Kinase, MB Form ; Apoptosis ; Polysaccharides/pharmacology* ; Superoxide Dismutase/metabolism* ; 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/analogs & derivatives*

BACKGROUNDIschemic postconditioning (I-postC) is a newly discovered and more amenable cardioprotective strategy capable of protecting the myocardium from ischemia/reperfusion (I/R) injury. Endoplasmic reticulum (ER) is a principal site for secretary protein synthesis and calcium storage. Myocardial I/R causes ER stress and emerging studies suggest that the cardioprotection has been linked to the modulation of ER stress. The aim of the present study was to determine whether cardioprotection of I-postC involves reduction in ER stress through calcineurin pathway.

METHODSIn the in vivo model of rat myocardial I/R, myocardial infarct size was measured by triphenyltetrazolium chloride (TTC) staining and apoptosis was detected using terminal eoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. Expression of calreticulin, C/EBP homologous protein (CHOP), caspase-12, and activation of caspase-12 in myocardium were detected by Western blotting. The activity and expression of calcineurin in myocardium were also detected.

RESULTSI-postC protected the I/R heart against apoptosis, myocardial infarction, and leakage of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB). I-postC suppressed I/R-induced ER stress, as shown by a decrease in the expression of calreticulin and CHOP, and caspase-12 activation. I-postC downregulated calcineurin activation in myocardium subjected to I/R.

CONCLUSIONI-postC protects myocardium from I/R injury by suppressing ER stress and calcineurin pathways are not associated with the I-postC-induced suppression of ER stress-related apoptosis.

Animals ; Apoptosis ; physiology ; Blotting, Western ; Calcineurin ; metabolism ; Creatine Kinase, MB Form ; blood ; Endoplasmic Reticulum Stress ; physiology ; Hemodynamics ; Ischemic Postconditioning ; L-Lactate Dehydrogenase ; blood ; Male ; Myocardial Infarction ; blood ; metabolism ; Myocardial Reperfusion Injury ; blood ; metabolism ; Myocardium ; metabolism ; pathology ; Myocytes, Cardiac ; cytology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; metabolism

OBJECTIVESTo explore serum cytokines levels (including IL-1beta, sIL-2R, IL-6, TNF-alpha, and IFN-upsilon) and their significance in patients with acute coronary syndrome (ACS) and the subsequent follow-ups, with attempt to estimate the role of various serum inflammatory markers in the diagnosis and assessment of ACS.

METHODSThe study population include 40 patients with acute myocardial infarction (AMI), 40 patients with unstable angina pectoris (UAP), and 40 controls. Among the 80 patients, 60 patients attended a follow up 4 months later. Serum inflammatory markers including IL-1beta, slL-2R, IL-6, TNF-alpha, and IFN-upsilon were measured by enzyme linked immunosorbent assay.

RESULTSSerum IL-1beta, sIL-2R, IL-6, TNF-alpha were significantly higher in AMI group or UAP group compared to the control group and became significantly lower 4 months later in the follow-up patients. Serum levels of IFN-upsilon shows no significant difference between AMI group or UAP group and controls, also showing no significant change when measured in follow up patients. There was no correlation between serum creatine kinase-MB isoenzyme levels and serum inflammatory markers either in UAP or AMI group. Furthermore, when divided into two subgroups using Wagner's QRS scoring system in the AMI group, there is no difference of each serum inflammatory marker between < or = 6 scores group and > 6 scores group.

CONCLUSIONSerum levels of certain inflammatory markers may have some diagnostic value for ACS, and can be a useful marker reflecting disease stability.

Aged ; Angina, Unstable ; blood ; diagnosis ; Biomarkers ; blood ; Creatine Kinase ; blood ; Creatine Kinase, MB Form ; Cytokines ; blood ; Female ; Follow-Up Studies ; Humans ; Interferon-gamma ; blood ; Interleukin-1 ; blood ; Interleukin-6 ; blood ; Isoenzymes ; blood ; Male ; Middle Aged ; Myocardial Infarction ; blood ; diagnosis ; Receptors, Interleukin-2 ; blood ; Tumor Necrosis Factor-alpha ; metabolism