Optimization and validation of RP-HPLC method for simultaneous estimation of palbociclib and letrozole

A simple, rapid, and robust RP-HPLC method have been developed and validated to measure palbociclib (PB) and letrozole (LT) at single wavelength (254?nm). A isocratic elution of samples performed on Intersil C₈ (4.6?mm?×?250?mm particle size 5?μm) column with mobile phase consisting 0.02 M sodium dihydrogen phosphate buffer (pH 5.5): acetonitrile: methanol (80:10:10 v/v/v) delivered at flow rate 1.0?mL?min^?1. A good linear response was achieved over the range of 5–50?μg?mL^?1. The LODs for PB and LT were found to be 0.098 and 0.0821 µg?mL^?1, while the LOQs for PB and LT were 0.381–0.315 µg?mL^?1, respectively. The method was quantitatively evaluated in terms of system suitability test, linearity, precision, accuracy (recovery) and robustness as per standard guidelines. The method is simple, convenient and suitable for the analysis of PB and LT in bulk drug.     

Influence of sonophoresis and chemical penetration enhancers on percutaneous transport of penbutolol sulfate

The effect of ultrasound and chemical penetration enhancers on transcutaneous flux of penbutolol sulfate across split-thickness porcine skin was investigated. Penbutolol sulfate is a potent, noncardioselective beta-blocker, which is used for the management of hypertension. The drug is one of the most lipid soluble of the β-adrenoceptor antagonists used clinically. It has an n-octanol/pH 7.4 buffer partition coefficient of 179 compared to a value of 22 for propranolol. The amount of penbutolol sulfate transported across the skin is low. In this project, we studied the effect of sonophoresis and chemical penetration enhancers on transdermal delivery of penbutolol sulfate. Low-frequency sonophoresis at a frequency of 20?kHz increased transcutaneous flux of penbutolol sulfate by 3.5-fold (27.37?±?μg?cm^?2?h^?1) compared to passive delivery (7.82?±?1.72?μg?cm^?2?h^?1). We also investigated the effect of 50% ethanol, 1% limonene and 2% isopropyl myristate (IPM) on transcutaneous permeation of penbutolol sulfate. IPM, ethanol and limonene at the concentration of 1%, 50% and 2%, respectively, increased the steady-state flux values of penbutolol sulfate 2.2- (17.07?±?3.24?μg?cm^?2?h^?1), 2.6?- (19.40?±?6.40?μg?cm^?2?h^?1) and 3.4-times (26.38?±?5.01?μg?cm^?2?h^?1) compared to passive delivery (7.76?±?2.9?μg?cm^?2?h^?1). The results demonstrate that although there were slight increases in flux values, ultrasound, ethanol, limonene and IPM did not significantly enhance the transdermal delivery of penbutolol sulfate. Future studies will examine ways of optimizing sonophoretic and chemical enhancer parameters to achieve flux enhancement.     

The essential oils chemical compositions and antimicrobial,antioxidant activities and toxicity of three Hyptis species

Abstract

Context: Hyptis suaveolens (Linn.) Poit., Hyptis rhomboidea Mart. et Gal., and Hyptis brevipes Poit., are three species of Hyptis Jacq. (Lamiaceae). Hyptis suaveolens is used for the treatment of fever, headache, gastrointestinal bloating and rheumatism in the traditional folk medicine; Hyptis rhomboidea for hepatitis, ulcer and swollen poison; and Hyptis brevipes for asthma and malaria.

Objective: To characterize chemical compositions of the oils from three Hyptis species and evaluate their potential antimicrobial, radical scavenging activities and toxicities against brine shrimp.

Materials and methods: The oils were obtained by hydrodistillation, and their chemical compositions were investigated by gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentrations (MICs) were determined using the tube double-dilution technique. The antioxidant activities were investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and toxicities by the brine shrimp bioassay.

Results: Forty-seven, 33 and 28 constituents of oils isolated, respectively, from H. suaveolens, H. rhomboidea and H. brevipes were identified. Among the essential oils, the strongest antioxidant activity was exhibited by H. brevipes with an SC₅₀ value of 2.019?±?0.25?μg?mL^?1. The H. brevipes oil exhibited the strongest antimicrobial activity (3.125–6.25?μg?mL^?1) on pathogens employed in the assay. They all showed significant toxicities with median lethal concentration (LC₅₀) values of 62.2?±?3.07?μg?mL^?1, 65.9?±?6.55?μg?mL^?1 and 60.8?±?9.04?μg?mL^?1, respectively.

Discussion and conclusions: The three Hyptis species oils possess strong antimicrobial activities and toxicities. Hyptis rhomboidea and H. brevipes showed considerable antioxidant activity compared to the positive control.     

Delivery of atovaquone and proguanil across sublingual membranes,in vitro

Malarone^?, a combination of atovaquone (AT) and proguanil (PR), is indicated for the prophylaxis and treatment of uncomplicated Plasmodium falciparum malaria. This study aimed to determine in vitro the feasibility of delivering the combination of AT and PR as a spray formulation via the sublingual route, using Franz diffusion cells incorporating porcine sublingual mucosa. Firstly, 1?mg mL^?1 of each drug in 20% 1,8-Cineole in ethanol was used; and secondly, 5?mg mL^?1 AT and 1?mg mL^?1 PR in 20% 1-methyl-2-pyrrolidone in ethanol was examined, dosed every 2?h over a 12-h period and receptor phase samples were analyzed by HPLC. From the first study, mean fluxes for AT and PR were 12.89?±?1.2 and 5.88?±?0.9 µg cm^?2 h^?1 respectively; pharmacokinetic calculations indicated that these fluxes were insufficient to achieve the target plasma concentrations for AT and PR of 1.4 µg mL^?1 and 200?ng mL^?1 respectively, in the treatment of falciparum malaria. However, in the second study, the fluxes of AT and PR increased to 50.92?±?20.8 and 12.01?±?1.5 µg cm^?2 h^?1 respectively, and pharmacokinetic calculations indicated that therapeutic plasma concentrations are attainable for pediatric application.     

Simultaneous LC determination of rosuvastatin, lisinopril, captopril, and enalapril in API, pharmaceutical dosage formulations, and human serum

A sensitive, economical, and rapid LC method for the quantification of CVD’s rosuvastatin, lisinopril, captopril, and enalapril in bulk drug, pharmaceutical dosage formulations and in human serum has been developed and validated. Chromatographic separation was performed by methanol:water (75:25?v/v) as mobile phase whose pH was adjusted to 3.0 by o-phosphoric acid; flowing at a rate of 1.0?mL?min^?1 through pre-packed Purospher Star C18 (5?μm, 25?×?0.46?cm) column at ambient temperature. UV detection was performed at isosbestic point 214?nm. The method shows good linearity in the range of 0.5–25?μg?mL^?1 for rosuvastatin (R ²?=?0.998) and 1–50?μg?mL^?1 for lisinopril, captopril and enalapril (R ²?=?0.999). All LOD values were ≤130 and LOQ?≤?370?ng?mL^?1 for API and human serum. The % recoveries of all drugs were between 98.07 and 102.51% in dosage formulations and human serum. The ICH guidelines were followed for the validation of method. The method can be employed for pharmacokinetic studies, routine QC analysis of dosage formulations, and laboratory analysis in blood samples of high cholesterol and hypertension patients.     

Evaluation of cytotoxic effects and oxidative stress with hydroxyapatite dispersions of different physicochemical properties in rat NR8383 cells and primary macrophages

Enhanced cytotoxicity and oxidative stress through reactive oxygen species (ROS) formation are discussed as relevant parameters regarding potential hazardous properties of nanomaterials. In this study, the biocompatibility of five hydroxyapatite materials of different size and morphology, i.e., nano/needle-shaped (HA-NN), nano/rod-like (HA-NR), nano/plate-like (HA-NP), fine/dull needle-shaped (HA-FN), and a hydroxyapatite–protein-composite (HPC), was investigated in rat NR8383 and primary alveolar macrophages. Lipopolysaccharide (LPS) and DQ12 quartz served as positive controls. In the water-soluble tetrazolium salt 1 (WST-1) and lactate dehydrogenase (LDH) assays with NR8383 cells, no cytotoxicity was observed for HPC and the pure hydroxyapatite samples up to 3000 μg/ml, while HA-FN showed a significant effect at the highest dose in the LDH assay. In primary cells, no cytotoxicity was observed with all samples up to 300 μg/ml. ROS generation measured by electron paramagnetic resonance (EPR) technique was significantly enhanced with HA-NN and HPC in NR8383 cells. No effect was detected in primary cells, which are considered more relevant to physiological conditions. All hydroxyapatites elicited TNF-α release from the NR8383 cells, but with significantly lower potency than DQ12 quartz and LPS. In conclusion, combined findings in both cell types support a good biocompatibility of the pure hydroxyapatite samples as well as of the hydroxyapatite–protein-composite.     

Antiplasmodial activity of extracts of 25 cyanobacterial species from coastal regions of Tamil Nadu

Context: Marine cyanobacteria offer considerable potential to isolate new antimalarials to meet a pressing need of our times.

Objective: To explore the antiplasmodial properties of marine cyanobacteria.

Materials and methods: Cyanobacterial samples collected from the coastal regions of Tamil Nadu were identified using light microscopy, and the strains were cultivated in ASN-III medium. Organic extracts (0–100?µg?mL^?1) of 25 in vitro mass-cultivated cyanobacteria, prepared using methanol: chloroform mixture (1:1?v/v) were evaluated for their antiplasmodial activity against chloroquine-sensitive and -resistant strains of Plasmodium falciparum by fluorescence-based SYBR Green I assay where chloroquine was used as a control. To detect the toxic effects of cyanobacterial extracts against red blood cells, the invasion, maturation, and growth rate of malarial parasites in cyanobacterial extracts pre-treated versus untreated erythrocytes were quantified microscopically. Mammalian cell line (HeLa) was used to determine cyanobacterial extract toxicity using the MTT assay.

Results: The extracts of Lyngbya aestuarii Liebm. ex Gomont CNP 1005 (C12) Oscillatoria boryana BDU 91451 (C22) and Oscillatoria boryana Bory ex Gomont BDU 141071 (C18) showed promising antiplasmodial activity (IC₅₀?=?18, 18, and 51?μg?mL^?1 respectively) against Pf3D7. Pretreatment of red blood cells with IC₁₀₀ of C12, C18, and C22 (40, 100, and 40?µgmL^?1, respectively) did not significantly influence the invasion, maturation, and growth rate of malarial parasites in comparison with untreated RBC controls suggesting a lack of toxicity to host cells. MTT assay based IC₅₀ (>200?μg?mL^?1) of these extracts against HeLa cell line also indicates their high selectivity against the malaria parasite.

Discussion and conclusion: These exploratory studies suggest the possibilities of development of new antimalarial compounds from marine cyanobacteria.     

Anticholinesterase,antioxidant, analgesic and anti-inflammatory activity assessment of Xeranthemum annuum L. and isolation of two cyanogenic compounds

Context: Xeranthemum annuum L. (Asteraceae) (XA) is an ornamental and medicinal species with limited bioactivity and phytochemical data.

Objective: Identification of anticholinesterase, antioxidant, anti-inflammatory and analgesic effects of the flower and root–stem (R-S) extracts of XA.

Materials and methods: Anticholinesterase (at 100?μg mL^?1) and antioxidant (at 1000?μg mL^?1) effects of various extracts were evaluated via microtiter assays, while anti-inflammatory and analgesic effects of the R-S extracts were tested using carrageenan-induced hind paw oedema (100 and 200?mg kg^?1) and p-benzoquinone (PBQ) writhing models (200?mg kg^?1) in male Swiss albino mice. The R-S ethanol extract of XA was subjected to isolation studies using conventional chromatographic methods.

Results: Most of the extracts showed inhibition over 85% against butyrylcholinesterase and no inhibition towards acetylcholinesterase. The flower chloroform and the R-S ethyl acetate extracts were most effective (97.85?±?0.94% and 96.89?±?1.09%, respectively). The R-S ethanol extract displayed a remarkable scavenging activity against DPPH (77.33?±?1.99%) and in FRAP assay, while the hexane extract of the R-S parts possessed the highest metal-chelating capacity (72.79?±?0.33%). The chloroform extract of the R-S caused a significant analgesic effect (24.4%) in PBQ writhing model. No anti-inflammatory effect was observed. Isolation of zierin and zierin xyloside, which were inactive in anticholinesterase assays, was achieved from the R-S ethanol extract.

Discussion and conclusion: This is the first report of anticholinesterase, antioxidant, analgesic and anti-inflammatory activities and isolation of zierin and zierin xyloside from XA. Therefore, XA seems to contain antioxidant and BChE-inhibiting compounds.     

Biological activities of ethyl acetate extract of different parts of Hyssopus angustifolius

Context: Hyssopus angustifolius M. Bieb. (Lamiaceae) is one of the most important medicinal plants in Iranian traditional medicine for the treatment of lung inflammation, laryngitis and cough relief. Much attention has been paid to this medicinal plant because of its traditional uses.

Objective: The present study examined the antioxidant and antihemolytic activities of ethyl acetate extract of stems, leaf and flowers of Hyssopus angustifolius.

Materials and methods: Antioxidant activity of extracts was evaluated by employing six different models, i.e., DPPH, nitric oxide and hydrogen peroxide scavenging, metal chelating and reducing power activities and hemoglobin-induced linoleic acid system. Also, antihemolytic activity was evaluated against hydrogen peroxide-induced hemolysis.

Results: Flowers extract showed the better activity than leaf and stems extracts in DPPH radical scavenging activity (IC₅₀ was 275.4?±?7.6 μg mL^?1). Leaf, stems and flowers extracts showed good nitric oxide scavenging activity (IC₅₀ were 376.6?±?11.4 µg mL^?1 for flowers, 297.6?±?9.6 μg mL^?1 µg mL^?1 for leaves and 837.8?±?19.2 µg mL^?1 for stems). The leaf extract exhibited better hydrogen peroxide scavenging and Fe²⁺ chelating activity than stems and flowers extracts. In hemoglobin-induced linoleic acid system, all of the extracts exhibited very good activity. Also, extracts show weak reducing power activity. The ethyl acetate extract of leaf showed better antihemolytic activity than the flower and stems (IC₅₀ was 94.0?±?2.4 μg mL^?1).

Discussion and conclusion: These findings give a scientific basis to the traditional usage of Hyssopus angustifolius, also showing its potential as rich sources of natural antioxidant compounds.     

Cationic polystyrene nanoparticle and the sea urchin immune system: biocorona formation,cell toxicity,and multixenobiotic resistance phenotype

Abstract

In order to assess the impact of nanoplastics on marine species, polystyrene nanoparticles (PS NPs) have been largely used as model particles. Here we studied the effects of 50?nm amino-modified PS-NH₂ on Mediterranean sea urchin Paracentrotus lividus immune system cells (coelomocytes) in the presence of celomic fluid (CF) and at different NP concentrations (1, 5, 10, and 25?μg mL^?1) and experimental conditions (absence or presence of EDTA). PS-NH₂ acquired a protein corona once incubated with CF, dominated by the toposome precursor protein (TPP). In short-term cultures, a significant concentration- and time-dependent decrease in lysosomal membrane stability and apoptotic-like nuclear alterations were observed in phagocytes upon exposure to PS-NH₂ (10 and 25?µg mL^?1) in CF but they resulted abolished in the presence of EDTA confirming the role of TPP in triggering PS-NH₂-coelomocytes interaction and toxicity. PS-NH₂ did not alter MXR phenotype but the observed dose-dependent decrease in calcein accumulation suggests the ability of PS-NH₂ to affect pump’s efflux activity. Overall results encourage additional studies on positively charged nanoplastics, since the observed effects on sea urchin coelomocytes as well as the TPP corona formation might represent a first step for addressing their impact on sensitive marine species.     

The effect of acute exposure to coarse particulate matter air pollution in a rural location on circulating endothelial progenitor cells: results from a randomized controlled study

Abstract

Context: Fine particulate matter (PM) air pollution has been associated with alterations in circulating endothelial progenitor cell (EPC) levels, which may be one mechanism whereby exposures promote cardiovascular diseases. However, the impact of coarse PM on EPCs is unknown.

Objective: We aimed to determine the effect of acute exposure to coarse concentrated ambient particles (CAP) on circulating EPC levels.

Methods: Thirty-two adults (25.9?±?6.6 years) were exposed to coarse CAP (76.2?±?51.5?μg?m^?3) in a rural location and filtered air (FA) for 2 h in a randomized double-blind crossover study. Peripheral venous blood was collected 2 and 20 h post-exposures for circulating EPC (n?=?21), white blood cell (n?=?24) and vascular endothelial growth factor (VEGF) (n?=?16–19) levels. The changes between exposures were compared by matched Wilcoxon signed-rank tests.

Results: Circulating EPC levels were elevated 2 [108.29 (6.24–249.71) EPC?mL^?1; median (25th–75th percentiles), p?=?0.052] and 20 h [106.86 (52.91–278.35) EPC?mL^?1, p?=?0.008] post-CAP exposure compared to the same time points following FA [38.47 (0.00–84.83) and 50.16 (0.00–104.79) EPC?mL^?1]. VEGF and white blood cell (WBC) levels did not differ between exposures.

Conclusions: Brief inhalation of coarse PM from a rural location elicited an increase in EPCs that persisted for at least 20 h. The underlying mechanism responsible may reflect a systemic reaction to an acute “endothelial injury” and/or a circulating EPC response to sympathetic nervous system activation.     

Analgesic activity of Eugenia jambolana leave constituent: A dikaempferol rhamnopyranoside from ethyl acetate soluble fraction

Context: Eugenia jambolana Lam. (Myrtaceae) is a medicinal plant used in folk medicine for the treatment of diabetes, inflammation, and pain.

Objective: We investigated the antinociceptive effect of kaempferol-7-O-α-l-rhamnopyranoside]- 4′-O-4′-[kaempferol-7-O-α-l-rhamnopyranoside (EJ-01), isolated from the E. jambolana leaves.

Materials and methods: EJ-01 (3, 10, and 30?mg?kg^?1, orally) was assessed for peripheral (formalin-nociception and acetic acid-writhing) and central (hot plate and tail flick test) analgesic activity in mice and the in vitro anti-inflammatory activity (25, 50, and 100?µg?mL^?1) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells.

Results and discussion: EJ-01 (10 and 30?mg?kg^?1) significantly inhibited mean writhing counts (37.74 and 36.83) in acetic acid writhing and paw licking time (55.16 and 45.66?s) in the late phase of the formalin test as compared with the respective control (60.66 and 104.33?s). EJ-01 did not show analgesic activity in central pain models. Significant reduction in the tumor necrosis factor (TNF)-α (295.48, 51.20, and 49.47?pg?mL^?1) and interleukin (IL)-1β (59.38, 20.08, and 15.46?pg?mL^?1) levels were observed in EJ-01-treated medium (25, 50, and 100?µg?mL^?1) as compared with vehicle-treated control values (788.67 and 161.77?pg?mL^?1), respectively. Significant reduction in total nitrite plus nitrate (NO_x) levels (70.80?nmol) was observed in the EJ-01-treated medium (100?µg?mL^?1) as compared with the vehicle-treated value (110.41?nmol).

Conclusion: EJ-01 is a valuable analgesic constituent of E. jambolana leaves and this study supports the pharmacological basis for the use of this plant in traditional medicine for curing inflammatory pain.     

Alveolar macrophage cell line is not activated by exposure to polymeric microspheres

An in vitro cell culture model based on a rat alveolar macrophage (AM) cell line, NR8383, was used to determine if poly(l-lactide) (PLA) microspheres prepared by the precipitation with a compressed antisolvent (PCA) method can be taken up by AMs and activate AMs. To examine cellular uptake of microspheres, microspheres were labeled with rhodamine 6G. Using fluorescence microscopy, the uptake of microspheres by NR8383 cells was followed as a function of time, microsphere concentration, and susceptibility to lysosomotropic agents. To determine if microspheres can activate NR8383 cells, the oxidative burst and production of TNF-α by NR8383 cells following microsphere treatment was measured. Uptake of microspheres by NR8383 cells was dependent on microsphere concentration and appeared to occur via endocytosis, as uptake was significantly inhibited by the putative lysosomotropic agents, ammonium chloride and chloroquine. Furthermore, the microspheres do not appear to activate NR8383 cells, since microsphere exposure results in negligible oxidative burst and TNF-α production in NR8383. Microspheres prepared by the PCA method hold great potential in targeting drugs to AMs and, therefore, may be of utility for the treatment of diseases in which AMs play an important role, such as tuberculosis (TB).     

Physical and chemical characterization of mefenamic acid in different pharmaceutical dosage forms and their stability studies using novel RP-HPLC method

A novel RP-HPLC method for the determination of mefenamic acid in raw material, different pharmaceutical forms, and in human serum for routine analysis, therapeutic purposes, and stability studies was developed and validated. This study is also a collection of studies performed on the physical and chemical aspects of mefenamic acid. The method developed constitutes mobile phase, acetonitrile:acetic acid:water (72.5:1:26.5, v/v/v) at pH 3 and mefenamic acid was monitored with UV detection at 279?nm, eluting out at 3.98?min. The present HPLC method was found to be linear (100–300?μg?mL^?1), accurate, and least time consuming with very good recovery. The limits of detection of the method were found to be 10?μg?mL^?1. This method was also used to study the stability profile of mefenamic acid in tablets for 5?years and suspension for 4?years. The excipients present in the formulation did not interfere with the assay. The present method was also compared with the UV–visible technique and it was observed that HPLC method is more precise, sensitive, and accurate.     

Antioxidant and antidiarrheal activities of ethanol extract of Ardisia elliptica fruits

Context: Ardisia elliptica Thunb Lam. (Myrsinaceae) is widely used traditionally in the treatment of diarrhea related health disorders in Bangladesh.

Objective: The crude ethanol extract of Ardisia elliptica fruits (EFA) was evaluated for its antioxidant and antidiarrhoeal activities.

Materials and methods: DPPH radical scavenging, nitric oxide scavenging, reducing power and Fe⁺⁺ ion chelating ability were used for determining antioxidant activities and animal models were used for antidiarrheal activities such as the castor oil and magnesium sulfate-induced diarrhea, enteropooling induced by the administration of castor oil and magnesium sulfate at the doses of 250 and 500?mg/kg.

Results: The extract possessed a significant DPPH free radical scavenging activity with an IC₅₀ value of 30.75?μg/ml compared to ascorbic acid (IC₅₀: 7.89?μg/ml). The IC₅₀ values of the extract and ascorbic acid were 51.72 and 38.68?μg/ml, respectively, in nitric oxide scavenging assay. The IC₅₀ value of the extract for Fe⁺⁺ ion chelating ability (41.30?μg/ml) was also found to be significant compared to the IC₅₀ value of EDTA (22.57?μg/ml). The EFA also showed a significant protection (p?Conclusion: Therefore, the obtained results confirm the antioxidant and antidiarrheal activity of EFA and thus support the traditional uses of this plant as a modality for antioxidant and antidiarrheal activity.     

The effects of chromium on the growth and activity of a pentachlorophenol-degrading bacterium

The effects of chromium (or chromate, as supplied by CrO₃) on a pentachlorophenol-degrading Flavobacterium sp. (ATCC 53874) were examined in a liquid bacterial growth medium. Cr⁶⁺ concentrations ? 5.0 μg mL^?1 caused the complete inhibition of bacterial growth. The EC₂₅, EC₅₀, and EC₇₅ calculated after 96 h of incubation were 0.44, 1.44, and 3.82 μg mL^?1, respectively. Cr⁶⁺ caused an irreversible reduction in total cell yield during the 21-day incubation. Cr⁶⁺ also elicited an increase in the lag time recorded before there was measurable pentachlorophenol (PCP) degradation by this bacterium. There was also an increase in the overall time required for complete degradation of PCP to nondetectable levels. A similar response was noted with all PCP concentrations examined from 10 to 100 μg mL^?1. However, a more pronounced response occurred at the lower PCP concentrations. The significance of these data relative to the in situ use of PCP-degrading bacteria for site bioremediation is outlined. © 1994 by John Wiley & Sons, Inc..     

Natural Products: Anti-proliferative Effects of Lichen-derived Inhibitors of 5-Lipoxygenase on Malignant Cell-lines and Mitogen-stimulated Lymphocytes

Several lichen species have been used traditionally as medicinal plants. It has previously been shown that two low-molecular-weight lichen metabolites, lobaric acid isolated from Stereocaulon alpinum Laur. and protolichesterinic acid isolated from Cetraria islandica L. (Ach.), have in-vitro inhibitory effects on arachidonate 5-lipoxygenase. We have studied the effects of these compounds on cultured cells from man, including three malignant cell-lines (T-47D and ZR-75-1 from breast carcinomas and K-562 from erythro-leukaemia), as well as normal skin fibroblasts and peripheral blood lymphocytes. Both test substances caused a significant reduction in DNA synthesis, as measured by thymidine uptake, in all three malignant cell-lines; the dose inducing 50% of maximum inhibition (ED50) was between 1.1 and 24.6 μg mL^?1 for protolichesterinic acid and between 14.5 and 44.7 μg mL^?1 for lobaric acid. The breast-cancer cell-lines were more sensitive than K-562. The proliferative response of mitogen-stimulated lymphocytes was inhibited with a mean ED50 of 8.4 μg mL^?1 and 24.5 μg mL^?1 for protolichesterinic acid and lobaric acid, respectively. These concentrations are of the same order of magnitude as the IC50 values in the 5-lipoxygenase assay. Significant cell death (assessed by the MTS (3–4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and trypan blue exclusion) occurred in the three malignant cell-lines at protolichesterinic acid and lobaric acid concentrations above 20 and 30 μg mL^?1, respectively. In K-562 morphological changes consistent with apoptosis were detected. Up to 38% cell death was observed at 20 μg mL^?1 for protolichesterinic acid and 15 μg mL^?1 for lobaric acid in mitogen-stimulated lymphocytes but unstimulated lymphocytes were clearly less sensitive. In contrast, the DNA synthesis, proliferation and survival of normal skin fibroblasts were not affected at doses up to 20 μg mL^?1 for protolichesterinic acid and 30 μg mL^?1 for lobaric acid. We conclude that the anti-proliferative and cytotoxic effects observed might be related to the 5-lipoxygenase inhibitory activity of protolichesterinic acid and lobaric acid. These results open up the opportunity for future studies of these lichen metabolites with regard to their anti-tumour and anti-inflammatory properties.     

Barium sulfate products for roentgenographic examination of the gastrointestinal tract

Characteristics of barium sulfate contrast agents used in roentgenographic studies are described. Barium sulfate can be used as a single contrast agent in the gastrointestinal tract; it can also be used for positive contrast in studies that use air for negative contrast (double-contrast examinations). Barium sulfate can be used to opacify the GI tract in preparation for computerized tomography of the abdomen. Barium sulfate products are available in powder form or as viscous suspensions. Product formulas and barium sulfate concentrations are varied to produce adequate coating and visualization of the portion of the GI tract to be examined, and the dosage is determined by the specific procedure. Double-contrast studies delineate fine details of the GI mucosa; preparations used in these studies contain smaller barium particles than those used in single-contrast studies. Agents that produce carbon dioxide are usually administered for double-contrast studies; the gas distends the stomach or intestine so the barium can cover the entire surface. Formulations of barium sulfate products vary so that a product appropriate for the specific procedure can be selected. These products also vary in cost, ease of reconstitution, and, for oral preparations, acceptability to patients.     

Antimicrobial and antioxidant activities of crude extracts of two Nigerian chewing sticks

In vitro determinations of the antimicrobial and antioxidant activities of ethanol and aqueous extracts of Disthemonanthus benthamianus Baill. (Caesalpiniaceae) and Zanthoxylum zanthoxyloides Lam. (Rutaceae), which are used as chewing sticks in Nigeria, were investigated. The extracts were screened against eight strains of Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, one methicillin-resistant strain of Staphylococcus epidermidis, twelve strains of Pseudomonas aeruginosa, five strains of Candida albicans and four strains of Bacillus cereus. The in vitro antimicrobial assay was performed by using a Mast Multipoint Inoculator based on the principles of an agar dilution technique. The aqueous extracts had no inhibitory effects on any of the tested microorganisms. The ethanol D. benthamianus extract inhibited P. aeruginosa, E. faecalis, and B. cereus with MIC ≤ 2.64?mg mL^?1 and S. aureus and S. epidermidis with MIC ≤ 0.44?mg mL^?1. Z. zanthoxyloides ethanol extract was less effective but noteworthy was the MIC ≤ 2.52?mg mL^?1 against C. albicans and 0.28?mg mL^?1 against some S. aureus strains. D. benthamianus ethanol extract had the best antioxidant activity and Z. zanthoxyloides ethanol extract second best. IC₅₀ for DPPH free radical scavenging of these extracts were 87.76 and 128.28?μg mL^?1/mL, respectively; ascorbic acid equivalents were 2.4 and 9.5?mg mg^?1 and total antioxidant capacities using the FRAP assay were 4068.06?mM Fe⁺⁺ mg^?1 and 624.86?mM Fe⁺⁺ mg^?1, respectively. The ethanol extracts of D. benthamianus and Z. zanthoxyloides showed significant antimicrobial and antioxidant activities which could be beneficial in oral hygiene.     

Internalization,Cytotoxicity, Apoptosis,and Tumor Necrosis Factor-α Expression in Rat Alveolar Macrophages Exposed to Various Dusts Occurring in the Ceramics Industry

In 1997 The International Agency for Research on Cancer classified some exposures to crystalline silica as carcinogenic to humans. Such exposures were acknowledged to be very variable, and even in the same monograph it was admitted that coal dust, containing as much as 20% quartz, could not be classified. Clearly there is a need to develop methods for assessing any risks posed by various silica containing dusts in different workplaces. A European collective research project, SILICERAM, was launched with the aim of assessing the toxicity of various dusts in the ceramics industry and improving worker protection. This study examined the effect of particles, namely, DQ12 quartz, China clay, feldspar, and a sample resembling a typical mixture used in the ceramic industry (a “contrived sample” or CS), on NR8383, a rat alveolar macrophage (AM) cell line. Titanium dioxide and aluminum oxide were also used as negative controls. Confocal microscopy observations showed internalization of DQ12 and CS in NR8383. Cell viability decreased dramatically after a 2-h incubation exposure period with DQ12 (?71%). CS was less toxic than DQ12 at 2 h. China clay and feldspar were slightly cytotoxic to NR8383 cells. DQ12 induced apoptosis, with a smaller effect of CS and China clay. TNFα gene expression was analyzed by RT-PCR. DQ12, at a noncytotoxic dose of 10 μ g/cm², induced a significant expression of TNFα (+2 times increase). In contrast, similar doses of CS and China clay did not produce a significant increase, while TiO₂ and Al₂O₃ displayed no effect. Co-treatment with 10 μ M aluminum lactate significantly reduced the effects of silica-containing particles on cytoxicity, apoptosis, and TNFα expression.