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PubMed2003

Efficacies of the mosquitomagnet and counterflow geometry traps in North Queensland, Australia.

We conducted three trials near Cairns, Australia, to compare the numbers of mosquitoes collected with the standard Encephalitis Vector Surveillance (EVS) and Centers for Disease Control (CDC) light traps with the new MosquitoMagnet (MM) and counterflow geometry (CFG) traps with the use of a 4 x 4 latin square experimental design. The MM was generally equal to the performance of the CDC and CFG traps, ranking ahead of or equal to one or both traps in 2 of 3 trials, although there were no significant differences in the performances of the MM, CDC, and CFG traps. The EVS trap ranked last in all trials. The MM, being self powered and self baited via combustion of propane for up to 20 days without requiring a propane refill, would be suitable for collection of adult mosquitoes in remote areas that do not have access to dry ice.

Air Movements↗
PubMed2004

In vitro reactivation of tabun-inhibited acetylcholinesterase using new oximes--K027, K005, K033 and K048.

Four new AChE oximes for reactivation of acetylcholinesterase inhibited with tabun - K027 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide], K005 [1,3-bis(2-hydroxyiminomethylpyridinium) propane dibromide], K033 [1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide] and K048 [1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium) butane dibromide] were prepared. Their efficacies to reactivate tabun-inhibited acetylcholinesterase were studied and compared with the currently used acetylcholinesterase reactivators (pralidoxime, obidoxime and HI-6). Reactivator K048 seems to be promising reactivator of tabun-inhibited AChE. Its reactivation potency is significantly higher than the efficacy of HI-6 and pralidoxime, and comparable with the potency of the obidoxime at human relevant doses.

Animals↗
PubMed2004

[Use of phenylglyoxylic ketyl radicals in testing for antioxidative effects of various compounds].

The paper describes spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol, which takes place via radicals at ambient temperature. The primary product of the decomposition is short-living ketyl radicals of phenylglyoxalic acid, which are captured and stabilized by means of the spin trap of N-terc-butyl-alpha-phenylnitrone. The spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol served as the source of radicals for the determination of the antioxidative effect of known antioxidants: C-vitamin, E-vitamin, and selenomethionine. It was found that the above-mentioned antioxidants are effective scavengers of radicals of phenylglyoxalic acid. On the basis of these data, the method can be recommended for testing the antioxidative properties of other substances as potential antioxidants.

Antioxidants↗
PubMed2004

New 3-[4-(2,3-dihydro-14-benzodioxin-5-yl)piperazin-1-yl]-1-(5-substituted benzo[b]thiophen-3-yl)propanol derivatives with dual action at 5-HT(1A) serotonin receptors and serotonin transporter as a new class of antidepressants.

Compounds derived from 2,3-dihydro-(1,4-benzodioxin-5-yl)piperazine and benzo[b]thiophene with different substituents in 5 position (H, F, NO2, NH2, CH3 and OH) have been synthesized in order to obtain new dual antidepressant drugs. The final compounds were evaluated for in vitro 5-HT(1A) receptor affinity and serotonin reuptake inhibition by radioligand assays. Compounds 1-(5-nitrobenzo[b]thiophen-3-yl)-3-[4-(2,3-dihydro-1,4-benzodioxin-5-yl)piperazin-1-yl]propan-1-ol (4c) (Ki = 6.8 for 5-HT(1A) receptor and Ki = 14 for 5-HT transporter) and 1-(5-hydroxybenzo[b]thiophen-3-yl)-3-[4-(2,3-dihydro-1,4-benzodioxin-5-yl)piperazin-1-yl] propan-1-ol (4f) (Ki = 6.2 for 5-HT(1A) receptor and Ki = 18.2 for 5-HT transporter) showed the best results for both activities.

Animals↗
PubMed2004

In vitro reactivation of acetylcholinesterase inhibited by cyclosarin using bisquaternary pyridinium aldoximes K005, K033, K027 AND K048.

We have tested four new bisquaternary pyridinium acetylcholinesterase (AChE; EC 3.1.1.7) reactivators - K005 (1,3-bis(2-hydroxyiminomethylpyridinium) propane dibromide), K033 (1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide), K027 (1 -(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide) and K048 (1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium) butane dibromide) as the potential reactivators of AChE inhibited by cyclosarin. Their reactivation potencies were studied using standard in vitro reactivation test. Rat brain homogenate was used as the source of the enzyme. Oxime K033 seems to be the most potent reactivator of cyclosarin-inhibited AChE. Its reactivation potency is significantly higher than the efficacy of all other tested AChE reactivators.

Acetylcholinesterase↗
PubMed2004

[A new blocking method for DNA chip].

Suggested a new blocking method for DNA microarray: 1-iodo-propane. We compared the difference between the two block reagents and the blocking results in different blocking time. The results showed that 1-I-propane is batter-blocking reagent than succinic anhydride in DNA chip. 1h blocking time is enough for blocking.

Hydrocarbons, Iodinated↗
PubMed1992

Mercuric chloride-induced cytotoxicity and compensatory hypertrophy in rat kidney proximal tubular cells.

Previous work showed that uninephrectomized (NPX) rats are more susceptible to the nephropathy induced by some doses of HgCl2 than sham-operated (SHAM) rats. The aim of the present study was to investigate the cytotoxic effects of HgCl2 in proximal tubular (PT) cells isolated from the kidney(s) of both NPX and SHAM rats. The study was designed to test if isolated PT cells that have undergone compensatory hypertrophy in vivo are more sensitive to the cytotoxic effects of HgCl2 in vitro than PT cells isolated from the kidneys of control animals. PT cells were purified from suspensions of renal cortical cells by Percoll density gradient centrifugation. The cellular content of protein (mg/10(6) cells) was 68% higher and the cellular specific activity (mU/10(6) cells) of lactate dehydrogenase was 56% higher in PT cells isolated from NPX rats than in PT cells isolated from SHAM rats. The cytotoxicity of HgCl2, as assessed by inhibition of lactate dehydrogenase activity, exhibited a steep concentration dependence. In the presence of bovine serum albumin, PT cells from both NPX and SHAM rats displayed no signs of cellular injury at concentrations of HgCl2 less than or equal to 0.1 mM. At concentrations of HgCl2 greater than or equal to 0.25 mM, cellular necrosis occurred rapidly in all PT cells. In the absence of bovine serum albumin, cellular injury and death occurred at concentrations of HgCl2 as low as 0.01 mM. PT cells from NPX rats exhibited signs of cellular injury at lower concentrations of HgCl2 than PT cells from SHAM rats when BSA was absent from the extracellular medium. Preincubation of PT cells from both NPX and SHAM rats with glutathione provided the cells with concentration-dependent protection from the cytotoxic effects of HgCl2. Preincubation of PT cells from both NPX and SHAM rats with the chelating agent 2,3-dimercapto-1-propane sulfonate provided cells with complete protection from the cytotoxic effects of HgCl2 when the concentration of 2,3-dimercapto-1-propane sulfonate was slightly below or higher than the concentration of HgCl2. Results of this study demonstrate the usefulness of freshly isolated PT cells from NPX rats as an in vitro model system to investigate biochemical mechanisms by which compensatory renal growth alters susceptibility to chemical-induced nephrotoxicity.

Animals↗
PubMedDate not supplied

Dimensional accuracy analysis of implant framework castings from 2 casting systems.

PURPOSE: To compare the dimensional accuracy of implant framework castings from an argon vacuum casting machine with those from a centrifugal casting machine. MATERIALS AND METHODS: Three 4 x 10-mm external hex-type implants (3i/Implant Innovations) were embedded in an acrylic resin block 7 mm apart, with a 2 mm offset of the middle implant. Eight reference points were marked on the implant collars. Twenty implant bar frameworks were waxed with UCLA abutments, invested with a ringless system, and subjected to the same thermal cycle. Ten wax patterns were cast in gold alloy using an oxygen-propane torch and centrifugal casting system; 10 were cast using an argon vacuum casting machine (KDF; Denken). The White 1-screw technique was applied after sequentially tightening the mesial and distal abutment screws to 10 Ncm. Fit of the implant framework castings was evaluated by measuring the marginal opening between the casting and implant at the reference points. These measurements were averaged and statistically compared for differences. RESULTS: The mean marginal openings at the most distant measuring locations from the tightened retaining screw at location 1 was between 44 to 48 microm for the centrifugal system compared to between 28 to 32 mm for KDF (P < .01). For screws tightened at location 3, the mean marginal openings at the most distant measuring locations were between 40 to 51 mm for the centrifugal system compared to between 27 to 29 microm for KDF (P < .01). DISCUSSION: In comparison with the centrifugal casting and oxygen-propane system, the argon vacuum system was more accurate and user friendly and less technique-sensitive. CONCLUSION: The argon vacuum casting machine tested produced more accurate, better fitting implant-supported prosthesis frameworks than a conventional centrifugal casting system. The "1-screw" method of evaluating casting fit was most effective when either of the prostheses' end screws were tightened.

Analysis of Variance↗
PubMed1991

Comparison of production of volatile hydrocarbons by phenylhydrazine-induced peroxidation in rats chronically treated with lead.

We have studied the effect of a chronic pretreatment by lead on the peroxidation processes by measuring the production of the four main volatile hydrocarbons: ethane and pentane as index of lipid peroxidation; propane as marker of protein peroxidation and ethylene as index of both lipid and protein peroxidations. Our results have shown that: 1) lead alone did not increase the physiological formation of alkanes indicating that lead is not able per se to initiate the peroxidative processes; 2) after phenylhydrazine injection, lipid peroxidation makers were not modified, except pentane in male lead-treated rats. Conversely, ethylene and propane exhalation were increased 45 min after phenylhydrazine injection in lead-treated rats indicating a potentialisation of the oxidative effect of phenylhydrazine, mainly on proteins, by lead.

Animals↗
PubMed1990

[Physical properties of light-cured opaque resin. (1) Influence of monomer composition].

Light-cured opaque resins with excellent physical properties were prepared using five types of monomer liquid and titanium dioxide as the powder. The five opaque resin monomer liquid had the following monomer compositions. Methyl methacrylate (MMA)/di(methacryloxyethyl) trimethylhexamethylene diurethane (UDMA) = 70/30 (M-U), MMA/neopenthylglycol dimethacrylate (NPG)/UDMA = 45/45/10 (M-N-U), UDMA/MMA = 70/30 (U-M), 2,2-bis (4-methacryloxypolyethoxy phenyl) propane (2.6 E)/2,2-bis [4-(3-methacryloxy-2-hydroxy propoxy) phenyl] propane (Bis-GMA)/triethyleneglycol dimethacrylate (3 G) = 60/35/5(2.6-B-3) and 3 G/UDMA = 70/30 (3-U) by weight. The bond strength, photo-curability and handling properties of the opaque resin were improved. Three MMA-based opaque resins showed nearly the same values in Knoop hardness number, diametral tensile strength and shear bond strength. The depth of cure increased with the decrease in MMA content of monomer composition, while the amount of residual monomer decreased. The 2.6-B-3 opaque resin had nearly the same properties in depth of cure and Knoop hardness number as the 3-U opaque resin. However, the 2.6-B-3 and 3-U opaque resins had a diametral tensile strength more than twice as high as that of the U-M opaque resin. The bond strength of three MMA-based opaque resins showed 0MPa after 5,000 thermocycles, while the 2.6-B-3 opaque resin, about 16 MPa, and the 3-U opaque resin, about 25 MPa. Therefore, the bond strength of the opaque resin was influenced by monomer composition. 3G-UDMA opaque resin showed excellent physical properties and may be clinically acceptable to bond fixed prosthodontic composite.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1989

Enzymatic detoxification using lipophilic hollow-fiber membranes: IV. Glutathione conjugation reactions.

A hollow-fiber technique was used in the enzymatic glutathione conjugation of lipophilic toxins. Native enzyme was circulated on the external side of a lipophilic hollow-fiber membrane while the toxin-containing media (blood, plasma or aqueous solution) were circulated inside the fiber. Glutathione conjugation reactions were catalyzed by rat liver cytosol, with a specific glutathione transferase activity of 40 nmol/min/mg protein (acceptor: 1,2-epoxy-3-(p-nitrophenoxy)propane). Clearance rates of 1,2-epoxy-3-(p-nitrophenoxy)propane, phenylglycidether, styrene oxide, cis-9, 10-epoxystearic acid, cis-9, 10-epoxystearic acid methyl ester, 5a, 6a-cholesterol oxide, 16-, 17a-pregnenolone oxide, and p-nitrobenzylchloride were 10.44, 13.37, 32.25, 7.60, 7.31, 3.92, 4.20 and 29.24 nmol/mg protein/h/cm2 hollow-fiber surface respectively. This technique makes possible glutathione conjugation reactions with crude enzyme preparations over long periods without loss of activity from covalent immobilization and without loss of cofactor from (auto)oxidation. The lipophilic membrane ensures the absence of hemolysis, immunological hazards and hormone loss, while elimination of the toxin is not impaired.

Animals↗
PubMed1988

Characterization of the ATPase activity of the Mr 170,000 to 180,000 membrane glycoprotein (P-glycoprotein) associated with multidrug resistance in K562/ADM cells.

The Mr 170,000 to 180,000 membrane glycoprotein associated with multidrug resistance (P-glycoprotein) is involved in drug transport mechanisms across the plasma membrane of multidrug-resistant cells. We have recently reported the purification of P-glycoprotein. The purified P-glycoprotein was found to have an ATPase activity, which might be coupled with the active efflux of anticancer drugs. In the present study, we have further studied the properties of the P-glycoprotein ATPase activity by an immobilized enzyme assay procedure using a P-glycoprotein-antibody-Protein A-Sepharose complex. GTP was also hydrolyzed by the P-glycoprotein, although less efficiently than ATP. The ATPase activity of P-glycoprotein had an optimal pH range around neutrality (pH 6.5-7.4). The detergent concentration of 3-[(3-cholamidopropyl)dimethyl-ammonio]-1-propane sulfonate used for protein solubilization was essential for enzyme recovery. Maximum activity was obtained when 0.1-0.2% 3-[(3-cholamidopropyl)dimethyl-ammonio]-propane sulfonate was used, while higher concentrations markedly inhibited the ATPase activity. The ATPase activity was dependent on Mg2+; maximum activity was obtained at 2-10 mM. Manganese and cobalt could substitute for magnesium as ionic cofactors. Divalent cations such as Ca2+, Zn2+, Ni2+, Cd2+, and Cu2+ inhibited the Mg2+-catalyzed ATP hydrolysis. N-Ethylmaleimide and vanadate inhibited the ATPase activity, while sodium azide or ouabain had no effect. Anticancer agents such as vincristine and Adriamycin did not affect the enzyme activity. In contrast, verapamil and trifluoperazine, agents which inhibit active drug efflux and restore drug sensitivity in resistant cells, caused an increase in the P-glycoprotein ATPase activity suggesting that P-glycoprotein might be the target molecule of these agents.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

[Transport of monovalent cations in erythrocytes after low temperature preservation and treatment with cryoprotective agents].

The freezing-thawing of erythrocytes under protection of 1,2-propane diol and glycerol was studied for its effect on the intracellular content of K+,Na+ and state of their passive and active transport. The low-temperature conservation of cells under the effect of penetrating cryoprotectors does not change essentially the content of univalent cations. A significant increase in the Na+ transport is observed with application of the cryoprotective medium on the base of 1,2-propane diol.

Biological Transport↗
PubMed1982

Liver tumors induced by a new beta-adrenoreceptor blocking agent in female rats.

A newly synthesized beta-adrenoreceptor blocking agent, DL-1-(2-nitro-3-methyl-phenoxy)-3-tert-butylamino-propan-2-ol (ZAMI 1305), administered intragastrically for 6 months induced hepatocellular carcinomas in female outbred Wistar rats in a dose-dependent fashion but was harmless to the livers of male outbred Wistar rats. Experiments with castrated animals confirmed the dependence of the carcinogenic effect of ZAMI 1305 on the hormonal status of the rat. When an isomer of ZAMI 1305, DL-1-(2-nitro-5-methyl-phenoxy)-3-tert-butylamino-propan-2-ol (ZAMI 1327), and DL-practolol, which have pharmacologic activities similar to those of ZAMI 1305, were administered by the same experimental technique as used for ZAMI 1305, no liver tumors appeared either in male or female rats.

Adrenergic beta-Antagonists↗
PubMed1983

In vitro and in vivo DNA damage of male and female rat liver nuclei by oncogenic and nononcogenic beta blockers.

The beta blocker DL-1-(2-nitro-3-methyl-phenoxy)-3-tert-butylamino-propan-2-ol (ZAMI 1305), hepatocarcinogenic to the female rat, and the nononcogenic beta blockers DL-1-(2-nitro-5-methyl-phenoxy)-3-tert-butylamino-propan-2-ol (ZAMI 1327), DL-propranolol, and DL-atenolol were tested for their capacity to damage liver DNA in vitro and in vivo. As revealed by alkaline sucrose gradient analysis, all the beta blockers tested, with the exception of DL-atenolol, caused a dose-dependent DNA fragmentation when they were added in vitro to nuclei isolated from livers of both male and female Wistar rats. Analysis of the DNA sedimentation patterns in neutral sucrose gradients demonstrated the absence of DNA fragmentation, thus indicating that the drugs did not induce double-strand DNA breaks. When the beta blockers were administered in vivo, liver DNA damage was observed only in female Wistar rats treated with ZAMI 1305. A single injection of ZAMI 1305 caused the onset of two distinct episodes of DNA damage. The first episode occurred within 5 minutes, and the damage was repaired within 1 hour after the injection; the second, apparently spontaneous, episode occurred 14 hours after the injection, and the damage was more pronounced than that seen in the first episode and took a much longer time to subside. However, a second injection of ZAMI 1305 into female Wistar rats 8 hours after the first injection did not induce the immediate short-lived episode of DNA damage but, like the first injection, it caused late DNA damage that peaked about 16 hours after drug administration.

Adrenergic beta-Antagonists↗
PubMed1983

Mutagenicity of potassium alkanediazotates and their use as model compounds for activated nitrosamines.

The mutagenicity of a series of potassium alkanediazotates in the Ames assay was studied. These compounds were isolated as solids and are soluble in dimethyl sulfoxide. Upon addition to water, they form diazohydroxides (which are postulated intermediates in the decomposition of alpha-hydroxylated nitrosamines). The diazohydroxides decompose to electrophilic intermediates which may react with macromolecules or water. In the Ames assay, potassium diazotates produced his+ revertants in Salmonella typhimurium strains TA 100 and TA 1535 but not in strains TA 98, TA 1537, or TA 1538. Methane, methane-d3, ethane, propane, and phenylmethanediazotates were mutagenic in strain TA 100, and all diazotates with the exception of phenylmethanediazotate, produced revertants in TA 1535. The order of mutagenic potency of these compounds was: methane approximately equal to methane-d3 greater than ethane, greater than phenylmethane (TA 100) greater than propane greater than phenylmethane (TA 1535) = 0. All diazotates were direct-acting mutagens and produced revertants even when no liver 9000 X g supernatant (S9) fractions were present. S9 fractions inhibited the mutagenicity of potassium diazotates, and equivalent concentrations of S9 fractions (3 mg protein per plate) from either rat or hamster liver, whether induced or not, were equally effective. Bovine serum albumin was not as effective as S9 fractions in inhibiting diazotate mutagenesis, but heat-inactivated (70 degrees for 20 min) S9 fractions were as inhibitory of methanediazotate mutagenicity as native S9 fractions were at low protein concentrations. The half-lives of mutagenicity of methane- and ethanediazotates in aqueous solutions were identical (less than or equal to 15 sec); after less than 2 min in solution, these diazotates were rendered completely inactive. The implications of these studies for mechanisms of nitrosamine action and the use of potassium alkanediazotates as model compounds for activated nitrosamines are discussed.

Animals↗
PubMed1984

Effect of cytosolic components on the metabolism of the hydrazide iproniazid.

The effects of thiols, such as glutathione (GSH), and the cytosolic glutathione S-transferases on the microsomal metabolism of the hydrazide iproniazid to hydrocarbon products were investigated. Thiol compounds stimulated propane production and depressed propylene production. Addition of preparations of cytosolic proteins to the microsomal reaction mixtures in the presence of GSH depressed production of propane by more than 80% and propylene by 50% compared to the GSH-mediated reaction. The purified glutathione S-transferases A and B were most potent in eliciting this effect; isozymes AA, C, and E had little or no effect on hydrocarbon production. Further, a mixture of these purified isozymes in the concentrations known to exist in cytosol affected hydrocarbon production in a manner similar to cytosol. Experiments performed with isolated hepatocytes and an inhibitor of these cytosolic enzymes further supported the involvement of these enzymes in altered hydrocarbon production. These isozymes were subsequently shown to catalyze the formation of a GSH conjugate, S-(2-propyl)glutathione. The decreases in hydrocarbon production by microsomes in the presence of the glutathione S-transferases and GSH were accompanied by production of slightly larger amounts of conjugate. These data indicate that the cytosolic glutathione S-transferases interact with an oxidative microsomal metabolite of iproniazid to enzymatically produce an S-(2-propyl)glutathione conjugate and thus prevent formation of a reactive species which would otherwise chemically decompose to yield hydrocarbons or to covalently bind to cellular macromolecules.

Animals↗
PubMed1983

X-ray microanalysis of frozen-hydrated specimens.

The preparation of frozen-hydrated bulk specimens and sections for X-ray microanalysis starts with cryofixation, which is done either by rapid immersion into liquid propane, propane jet fixation or metal mirror fixation. Bulk specimens appropriate for the analysis in a scanning electron microscope (SEM) are obtained by cryofracturing the samples, coating, usually by a thin carbon layer, and cold transfer into the cold stage of the microscope. The X-ray microanalysis of bulk specimens is affected by an internal space charge which makes quantification difficult. Frozen-hydrated dry cut sections, varying in thickness between 60 and 2000 nm, are prepared by means of cryoultramicrotomy. After cold transfer into the cold stage of a scanning electron microscope or a scanning transmission electron microscope (STEM) the sections are analyzed in the frozen-hydrated and freeze-dried state. The reliability of the results with regard to structural recognizability and X-ray spectra depends considerably on the state of hydration. Particularly ultrathin sections in STEM show very low contrast and a great mass loss in the frozen-hydrated state in comparison with the freeze-dried state. In spite of the available concepts for quantification of X-ray data to obtain physiologically important wet weight concentrations of diffusible elements, the radiation damage at present turns out to be the most serious problem for X-ray microanalysis of frozen-hydrated sections.

Animals↗