Facile development, characterization, and evaluation of novel bicalutamide loaded pH-sensitive mesoporous silica nanoparticles for enhanced prostate cancer therapy.

It is a challenge to deliver therapeutics exclusively to cancer cells, while sparing the normal cells. However, pH-sensitive delivery systems have proved to be highly efficient in fulfilling this task due to their ability to provide on-demand and selective release of drug at acidic tumor sites. As a proof of concept, here pH responsive drug delivery system based on mesoporous core shell nanoparticles (NPs) surrounded with poly acrylic acid (PAA) layers were prepared employing a facile synthesis strategy. Bicalutamide (BIC) was encased into surface functionalized MCM-41 nanoparticles via electrostatic interactions. The synthesized NPs were characterized by nitrogen adsorption and desorption isotherms, SEM-EDS, TEM, LXRD, and WXRD. In vitro release studies demonstrated that BIC-MSN-PAA NPs exhibited a higher release in the acidic media which varied inversely with the increase in pH. Further, the results of cell cytotoxicity assay were evident that BICMSNs exhibited more potent killing of both PC-3 and LNCaP cells than free BIC. PAA-MSNs also exhibited an enhanced cellular uptake and prolonged circulation time in vivo. The results are suggestive of the fact that PAA functionalized MSNs can serve as an effective pH-responsive template and hold a great potential ahead in controlled release and effective cancer treatment.

Evaluation of biocidal efficacy of Chloramine T trihydrate on planktonic and sessile bacteria in a model cooling tower water system.

A model cooling tower system was experimentally seeded with Legionella pneumophila and real industrial cooling tower (CT) water has been run at the closest to full-scale system operating conditions. The water/biofilm samples were taken from the model system monthly, and the effectiveness of the different concentrations of Chloramine T trihydrate biocide was evaluated in terms of its ability to control both planktonic/sessile microbial populations. Although Chloramine T is a recommended commercial formulation for disinfecting CTs, there is a lack of published data on the efficacy of this compound against both planktonic and sessile populations in the cooling tower. Biocide response in both sessile/planktonic bacteria counts varied according to months. Tested biocide concentrations provided the clean tower conditions by reducing the concentration of heterotrophic plate count (HPC) below <104 cfu mL-1, L. pneumophila <10 cfu mL-1 and of adenosine triphosphate (ATP) values <300 relative light units (RLU), after 1, 3 and 24 h of exposure, during a 6-month period. There were no statistically significant differences in efficacy between concentrations in terms of reduction in the number of bacteria, decrease in ATP value and viability. The results revealed that Chloramine T can effectively control biofouling in cooling systems according to the limit values of the successful control program.

Antibiofilm Activity and Mechanism of Action of the Disinfectant Chloramine T on Candida spp., and Its Toxicity against Human Cells.

We evaluated the antifungal and anti-biofilm activity, mechanism of action and cytotoxicity of chloramine T trihydrate (CAT) against Candida spp. The Minimum Inhibitory and Fungicidal Concentrations (MIC/MFC) of CAT were determined. Changes in CAT-treated C. albicans growth kinetics and micromorphology were evaluated, as well as the mechanism of action, and its effects on biofilm. Cytotoxicity was assessed by the hemolysis method. The data were analyzed by inferential statistics (p ≤ 0.05). CAT showed antifungal activity against all strains, with MIC values ranging between 1.38 and 5.54 mmol/L (MIC75%: 2.77 mmol/L). CAT demonstrated an immediate and sustained action on C. albicans growth kinetics, particularly at 2 × MIC. This compound likely acts on the cell wall and membrane permeability simultaneously and was found to cause changes in C. albicans micromorphology. Tha antibiofilm activity of CAT was similar to that of sodium hypochlorite (p > 0.05) against mature biofilms. CAT was more effective than NaOCl in reducing mature biofilm upon 1-min exposure at 2 × MIC (24 h) and 4 × MIC (48 h) (p < 0.05). Toxicological analysis revealed that CAT had hemolytic activity between 61 and 67.7% as compared to 100% by NaOCl. CAT has antifungal and anti-biofilm properties, probably acting on both cell wall and membrane permeability, and showed low toxicity in vitro.

Impacts of chloramine-T treatment on antioxidant enzyme activities and genotoxicity in rainbow trout, Oncorhynchus mykiss (Walbaum).

Juvenile rainbow trout Oncorhynchus mykiss (Walbaum) were exposed to therapeutic, and higher concentrations of chloramine-T (Cl-T) to assess the effects of this chemical on the antioxidant enzyme system and genetic structure. Red blood cells acetylcholinesterase, ∆-aminolevulinic acid dehydratase, paraoxonase and liver glutathione S-transferase activity were increased at 10 and 20 mg L(-1) Cl-T-exposed fish, while they were decreased at 30 mg L(-1) Cl-T-exposed fish. On the other hand, liver catalase activity and liver protein levels increased at 10 mg L(-1) and decreased at 20 and 30 mg L(-1) concentrations of Cl-T. Liver super-oxide dismutase activity decreased at 10 mg L(-1) and 20 mg L(-1) Cl-T and increased at 30 mg L(-1) of Cl-T. Compared to control, comet assay indicated that Cl-T did not cause significant DNA damage to red blood cells of the fish. Results indicate that 10 or 20 mg L(-1) Cl-T can be safely used to prevent or treat external parasitic and bacterial infection of rainbow trout.

HTDP-2, a new synthetic compound, inhibits glutamate release through reduction of voltage-dependent Ca²âº influx in rat cerebral cortex nerve terminals.

AIM: The present study was aimed at investigating the effect of trans-6-(4-chlorobutyl)-5-hydroxy-4-(phenylthio)-1-tosyl-5,6-dihydropyridine-2(1H)-one (HTDP-2), a novel synthetic compound, on the release of endogenous glutamate in rat cerebrocortical nerve terminals (synaptosomes) and exploring the possible mechanism. METHODS: The release of glutamate was evoked by the K⁺ channel blocker 4-aminopyridine (4-AP) and measured by an on-line enzyme-coupled fluorimetric assay. We also used a membrane potential-sensitive dye to assay nerve terminal excitability and depolarization, and a Ca²âº indicator, Fura-2-acetoxymethyl ester, to monitor cytosolic Ca²âº concentrations ([Ca²âº](c)). RESULTS: HTDP-2 inhibited the release of glutamate evoked by 4-AP in a concentration-dependent manner. Inhibition of glutamate release by HTDP-2 was prevented by the chelating intraterminal Ca²âº ions, and by the vesicular transporter inhibitor bafilomycin A1, but was insensitive to the glutamate transporter inhibitor DL-threo-ß-benzyloxyaspartate. HTDP-2 did not alter the resting synaptosomal membrane potential or 4-AP-mediated depolarization whereas it decreased the 4-AP-induced increase in [Ca²âº](c). Furthermore, the inhibitory effect of HTDP-2 on the evoked glutamate release was abolished by the N-, and P/Q-type Ca²âº channel blocker ω-conotoxin MVIIC, but not by the ryanodine receptor blocker dantrolene, or the mitochondrial Na⁺/Ca²âº exchanger blocker CGP37157. CONCLUSION: Based on these results, we suggest that, in rat cerebrocortical nerve terminals, HTDP-2 decreases voltage-dependent Ca²âº channel activity and, in so doing, inhibits the evoked glutamate release.

Androgen receptor antagonists and anti-prostate cancer activities of some synthesized steroidal candidates.

In continuation of our previous work, a novel series of steroid derivatives were synthesized and their androgen receptor (AR) antagonist activities and in vivo antiandrogenic properties were evaluated. Twenty-one heterocyclic derivatives containing a cyanopyrane ring fused to a steroidal moiety were conveniently synthesized and screened for their antagonistic, antiandrogen and prostate anticancer activities comparable to that of bicalutamide as the reference control. Some of the compounds exhibited better antagonistic, antiandrogen and prostate anticancer activities than the reference controls. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). Synthetic steroidal structures fused to a substituted cyanopyrane ring seem to be a promising approach in the search for novel leads for potent antagonistic, antiandrogen and prostate anticancer agents.

Occupational asthma in professional cleaning work: a clinical study.

BACKGROUND: Several epidemiological studies have reported an increased risk of asthma among professional cleaners. To date, however, no analysis of large patient series from clinic of occupational medicine has been published. AIMS: To describe the cases of occupational asthma (OA) diagnosed at the Finnish Institute of Occupational Health (FIOH) during the period 1994-2004 in workers employed in professional cleaning work. METHODS: OA was diagnosed according to patient history, lung function examinations and specific challenge tests with measurements of the forced expiratory volume in 1 second and peak expiratory flow values. RESULTS: Our series comprised 20 patients, all female, with a mean age of 48.8 years (range 27-60 years). The mean duration of cleaning work before the onset of the respiratory symptoms was 14.3 years (range 1-36 years), and the mean duration of cleaning work before the FIOH examinations was 18.6 years (range 3-38 years). OA was triggered by chemicals in 9 cases (45%) and by moulds in 11 cases (55%). The chemicals were cleaning chemicals (wax-removing substances containing ethanolamines in five cases and a cleaning agent containing chloramine-T in one case) and chemicals used in the industrial processes at workplaces (three cases). Of the moulds, the most frequently associated with OA was Aspergillus fumigatus (nine cases). CONCLUSIONS: OA was attributed not only to cleaning chemicals but also to other chemicals used in work environments. Moulds are presented as a new cause of OA in cleaners.

Next generation risk assessment of human exposure to anti-androgens using newly defined comparator compound values.

Next Generation Risk Assessment (NGRA) can use the so-called Dietary Comparator Ratio (DCR) to evaluate the safety of a defined exposure to a compound of interest. The DCR compares the Exposure Activity Ratio (EAR) for the compound of interest, to the EAR of an established safe level of human exposure to a comparator compound with the same putative mode of action. A DCR ≤ 1 indicates the exposure evaluated is safe. The present study aimed at defining adequate and safe comparator compound exposures for evaluation of anti-androgenic effects, using 3,3-diindolylmethane (DIM), from cruciferous vegetables, and the anti-androgenic drug bicalutamide (BIC). EAR values for these comparator compounds were defined using the AR-CALUX assay. The adequacy of the new comparator EAR values was evaluated using PBK modelling and by comparing the generated DCRs of a series of test compound exposures to actual knowledge on their safety regarding in vivo anti-androgenicity. Results obtained supported the use of AR-CALUX-based comparator EARs for DCR-based NGRA for putative anti-androgenic compounds. This further validates the DCR approach as an animal free in silico/in vitro 3R compliant method in NGRA.

Ethyl mercury p-toluene sulfonanilide: lethal and reproductive effects on pheasants.

Ethyl mercury p-toluene sulfonanilide (active ingredient of Ceresan M) at a dietary concentration of 30 parts per million (12.5 parts of mercury per million) was lethal to adult ring-necked pheasants. Egg production and survival of third-week embryos were sharply reduced when breeders were maintained on feed containing 10 parts of this compound per million (4.2 parts of mercury per million).

Optimization and validation of a colorimetric assay for Tetrahymena sp. survival.

A colorimetric assay based on the reduction of 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide (MTT), for the quantification of Tetrahymena sp. survival is described. An increase in the concentration of Tetrahymena sp. cells from 0 to 1 x 10(6) cells/ml produced a linear (R(2)=0.9965) increase in the optical density (OD, 570-630 nm), and dead cells (pre-exposed to 250 mg/l formalin for 4 h) did not produce a background reading. Cells exposed to sublethal concentrations to formalin (100 mg/l or less for 4 h) recovered their growth. Using the MTT assay, we determined that Tetrahymena sp. is sensitive to formalin, chloramine-T, hydrogen peroxide, copper sulfate and NaCl. The sensitivity increased with increasing chemical concentrations and exposure time. Tetrahymena sp. was resistant to bromex and malachite green. The use of this assay in drug screening for the development of treatments for tetrahymenosis and as a bioassay to evaluate the toxicity of environmental toxicants is discussed.

E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate, is a novel, selective and competitive dipeptidyl peptidase-IV inhibitor.

Dipeptidyl peptidase IV (DPP-IV) inhibitors are expected to become a useful new class of anti-diabetic agent. The aim of the present study is to characterize the in vitro and in vivo profile of E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate, which is a novel imidazopyridazinone-derived DPP-IV inhibitor. E3024 inhibited recombinant human and mouse DPP-IV with IC50 values of approximately 100 nM. E3024 inhibited DPP-IV in human, mouse, rat and canine plasma with IC50 values of 140 to 400 nM. In contrast, E3024 did not inhibit DPP-8 or DPP-9 activity. Kinetic analysis indicated that E3024 is a competitive DPP-IV inhibitor. In Zucker fa/fa rats, E3024 (1 mg/kg) reduced glucose excursion after glucose load, with increases in plasma insulin and active glucagon-like peptide-1 levels. In fasted rats, this compound did not cause hypoglycemia. In a rat 4-week toxicological study, no notable changes were found at doses up to 750 mg/kg. The present preclinical studies indicate that E3024 is a novel selective DPP-IV inhibitor with anti-diabetic effects and a good safety profile.

Treatment of ichthyophthiriasis after malachite green. II. Earth ponds at salmonid farms.

We tested formalin, chloramine-T-formalin and Desirox-formalin, for use against white spot disease (ichthyophthiriasis) caused by Ichthyophthirius multifiliis at 3 salmonid farms (Salmo salar and S. trutta smolt reared in earth ponds). I. multifiliis disappeared from most individuals 4 to 5 wk after the first treatment (and after the first I. multifiliis were found) with all chemicals, indicating that combinations of these chemicals, and even formalin alone, can be used to lower the parasite burden in earth ponds to such a level that no mortality occurs. This was the case when the fish were treated frequently at the beginning of the infection. Treatment can be stopped once the fish have achieved immunity to ichthyophthiriasis. The developing immunity was also revealed by the distribution of ciliates in the course of the disease. At the beginning of the infection I. multifiliis individuals were randomly distributed among the fish, but after 2 to 3 wk, when all the fish were infected, ciliates had increased in numbers and were aggregated in such a way that some fish carried quite heavy burdens. However, over 60% of the fish were free of the parasites after 4 to 5 wk, and had few or no ciliates, meaning that the distribution was even more aggregated. Sea trout had fewer parasites than salmon, and they also recovered from infection earlier even though the treatments and ponds were similar, indicating variation in resistance to I. multifiliis between fish species. It was also evident that the chemicals and their concentrations must be planned carefully to suit the conditions at each farm.

Treatment of ichthyophthiriasis after malachite green. I. Concrete tanks at salmonid farms.

Since the use of malachite green was banned in many European countries, new alternative treatments have been tested to prevent white spot disease caused by Ichthyophthirius multifiliis. We tested formalin, potassium permanganate (KMnO4), chloramine-T, hydrogen peroxide (H2O2) and Per Aqua or Desirox alone or in combinations of 2 chemicals, one of which was always formalin, in 50 m2 concrete tanks at 2 farms producing salmon Salmo salar smolt in 2001 and 2002. Both Per Aqua and Desirox are combinations of peracetic acid, acetic acid and hydrogen peroxide. The alternative chemicals or their combinations can be used successfully to lower the parasite burden to such a level that no high mortality occurs during the first 4 wk after the start of an infection. This period of time allows the fish to develop immunity against these ciliates, and treatments can be reduced and stopped in due course. I. multifiliis decreased in number 3 to 4 wk after the beginning of the infection in all the treatments. Large differences in parasite burden and mortality occurred among the replicates in all except the Desirox-formalin tanks, which means that they are not as reliable as the malachite green-formalin used previously. It was also evident that the chemicals and their concentrations must be planned carefully to suit the conditions on each farm.

Environmental concentrations of anti-androgenic pharmaceuticals do not impact sexual disruption in fish alone or in combination with steroid oestrogens.

Sexual disruption in wild fish has been linked to the contamination of river systems with steroid oestrogens, including the pharmaceutical 17α-ethinylestradiol, originating from domestic wastewaters. As analytical chemistry has advanced, more compounds derived from the human use of pharmaceuticals have been identified in the environment and questions have arisen as to whether these additional pharmaceuticals may also impact sexual disruption in fish. Indeed, pharmaceutical anti-androgens have been shown to induce such effects under laboratory conditions. These are of particular interest since anti-androgenic biological activity has been identified in the aquatic environment and is potentially implicated in sexual disruption alone and in combination with steroid oestrogens. Consequently, predictive modelling was employed to determine the concentrations of two anti-androgenic human pharmaceuticals, bicalutamide and cyproterone acetate, in UK sewage effluents and river catchments and their combined impacts on sexual disruption were then assessed in two fish models. Crucially, fish were also exposed to the anti-androgens in combination with steroid oestrogens to determine whether they had any additional impact on oestrogen induced feminisation. Modelling predicted that the anti-androgenic pharmaceuticals were likely to be widespread in UK river catchments. However, their concentrations were not sufficient to induce significant responses in plasma vitellogenin concentrations, secondary sexual characteristics or gross indices in male fathead minnow or intersex in Japanese medaka alone or in combination with steroid oestrogens. However, environmentally relevant mixtures of oestrone, 17ß-oestradiol and 17α-ethinylestradiol did induce vitellogenin and intersex, supporting their role in sexual disruption in wild fish populations. Unexpectedly, a male dominated sex ratio (100% in controls) was induced in medaka and the potential cause and implications are briefly discussed, highlighting the potential of non-chemical modes of action on this endpoint.

Mutagenicity study of Remsen-Fahlberg saccharin and contaminants.

Saccharin and contaminants of commercial Remsen-Fahlberg saccharin were studied for mutagenic potential with the use of the Salmonella/microsome test, Basc-test in Drosophila melanogaster and micronucleus test in mice. In none of these tests were mutagenic effects of saccharin observed. Likewise, the ortho- and para-sulfamoylbenzoic acids (OSBA and PSBA) were ineffective. Para-toluenesulfonamide (PTS) and the major contaminant ortho-toluene-sulfonamide (OTS) exhibited weak mutagenic effects in a modified Salmonella/microsome test and in Drosophila. These results do not indicate mutagenic and therewith correlated carcinogenic potential of saccharin, but they emphasize the possible activity of contaminants.

Zinc-specific N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide as a selective nontoxic fluorescence stain for pancreatic islets.

Separation of the endocrine from the exocrine pancreatic tissue by fluorescence activated sorting has been limited by the lack of an ideal fluorescent label for islet tissue. Our studies indicates the zinc-specific stain N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide (TSQ), has characteristics ideal for use as a fluorescent label for islet tissue. Dispersed rat pancreas cells stained with TSQ produced bright blue fluorescence when excited by UV light (peak emission wavelength at 480 nm, maximal excitation at 365 nm). The fluorescence was specific for islet tissue as confirmed by counterstaining with the islet-specific stain dithizone and there was minimal background staining of exocrine tissue. Stained tissue remained brightly fluorescent for 2 hr, with some fading by 4 hr. Injection of TSQ into rats at a concentration sufficient to produce staining of islets produced no toxicity discernible at 4 months. The viability of isolated rat islets stained with TSQ was maintained as shown by supravital staining, in vitro secretion of insulin, and reversal of diabetes after transplantation of stained islets into diabetic syngeneic recipients.

[Ocular lesions induced by saccharin and its pollutants in the rat fetus]. / Lésions oculaires provoquées par la saccharine et ses polluants sur les foetus des rats.

The authors analyze and compare the teratogenic effects produced on the embryo eyes of rats by Maumee saccharin, by non purified Remsem saccharin and several pollutants. The study has been made on 2708 embryos of rats whose mothers have received per os several pollutants at several rates; 16 diets have been studied. The histological lesions are described: the cataract, the retinal coloboma, the major microphthalmos, the anophthalmos, the presence of aberrant nervous fibers, the anarchic globes. The authors describe the retinal eversion phenomenon in the retinal coloboma as well as its repercussion on the ocular malformations (retinal dysplasia and colobomatous cyst of the orbit). The presence of aberrant nervous fibers inside the retinal coloboma could explain the cases of double papilla, which were observed in clinic. The major microphthalmia are frequent. The serious anophthalmia are explained by an early perturbation of the embryogenesis. The anarchic globes could be interpreted as a form of congenital cystic eye. Under the different pollutants of the saccharin, four of them are more toxic: it is the ortho-sulfobenzoic acid, the para-sulfobenzoic acid, the para-sulfamolybenzoic acid, the para-toluenesulfonamide which communicate the Remsen saccharin its teratogenic effect. On the other hand, the ortho-toluene sulfonamide is without any teratogenic effect. The authors conclude on the necessity of a large purity of the commercial saccharin.

[Tanfelam: synthesis, study of ovicidal activity, and acute toxicity]. / Sintez, issledovanie ovitsidnoi aktivnosti i ostroi toksichnosti preparata Tanfelama.

The papers describes the synthesis of N-(2-piperidinoethyl)-N-tosyl-n-anisidine (Tanfelam) which showed a 100% ovicidal activity when tested by the Harada and Mori methods (in vitro inhibited N.brasiliensis hatching and development test). Tanfelam has been transferred for in-depth tests.

Investigation of chloramine-T impact on crayfish Astacus leptodactylus (Esch., 1823) cardiac activity.

The crayfish play an essential role in the biomonitoring and may reflect ambient water quality through the biochemical, behavioural and physiological reactions. To assess whether narrow-clawed crayfish Astacus leptodactylus can respond by heart rate changes to presence in water of such biocide as chloramine-T, adult males were exposed to its low (2 and 5 mg L(-1)), moderate (10 mg L(-1), commonly used in industry and aquaculture) and exceeded (20 and 50 mg L(-1)) concentrations. In addition, a physical stress test evaluated energy expenditure following the chemical trials. Three key reactions (cardiac initial, first-hour and daily prolonged exposure) were discussed with particular focus on crayfish initial reaction as the most meaningful in on-line water quality biomonitoring. After short-term exposure to both chloramine-T concentrations, crayfish were found to respond rapidly, within 2-5 min. According to heart rate changes, the 1-h exposure did not adversely affect crayfish at either concentration, as well as during daily exposure to 10 mg L(-1). As assessed by the heart rate, the 24-h exposure to 50 mg L(-1) of chloramine-T was toxic for crayfish and led to substantial loss of energy that became apparent during subsequently conducted physical stress. The results supported a hypothesis that crayfish vital functions are connected with environment they inhabit closely enough to serve as biological monitors. Crayfish were tolerant to short-term chloramine-T exposure, while rapid crayfish reaction to an increased chemical level indicated their high sensitivity, an essential attribute of real-time environmental assessment.