Chronic toxicity of verapamil on juvenile rainbow trout (Oncorhynchus mykiss): effects on morphological indices, hematological parameters and antioxidant responses

In this study, the toxic effects of verapamil (VRP) were studied on juvenile rainbow trout, Oncorhynchus mykiss, by chronic semi-static bioassay. Fish were exposed to sublethal concentrations of VRP (0.5, 27 and 270 μg/L) for 0, 21 and 42 d. Multiple biomarkers were measured, including morphological indices, hematological parameters and antioxidant responses of different tissues (brain, gill, liver, muscle and intestine). Based on the results, there was no significant change in all parameters measured in fish exposed to VRP at environmental related concentration, but VRP-induced stress in fish exposed to higher concentrations reflected the significant changes of physiological and biochemical responses. Through principal component analysis and integrated biomarker response assessment, effects induced by VRP-stress in each test group were distinguished. Additionally, all parameters measured in this study displayed various dependent patterns to VRP concentrations and exposure time using two-way ANOVA statistic analysis. In short, the multiple responses in fish indicated that VRP induced physiological stress and could be used as potential biomarkers for monitoring residual VRP in aquatic environment; but molecular and genetic mechanisms of these physiological responses in fish are not clear and need to be further studied.     

转"全鱼"GH基因鲤鱼胸腺发育差异表达基因的筛选与鉴定

采用显微注射方法,获得了转"全鱼"生长激素(GH)基因鲤鱼(转基因鱼),应用抑制性差减杂交(SSH)技术,构建了4月龄F3转基因鱼胸腺发育差减cDNA文库,筛选并鉴定了与胸腺发育相关的81个与已知基因同源的表达序列标签(EST).这些EST至少代表69个基因.根据基因的作用将其分为5类:18个与免疫和细胞防御有关;23个参与细胞生长、发育和分化等代谢过程;3个参与细胞信号传导和周期调控;8个在转录和表达调节中发挥作用;17个为核糖体蛋白基因,表明转基因鱼胸腺细胞处于活跃的蛋白合成状态.应用RT-PCR和虚拟Northern杂交技术进一步证实其中的若干基因在转基因鱼胸腺组织中的表达量增加.实验结果为阐明转植GH基因促进鲤鱼胸腺发育的相关分子机制提供了依据.     

The distribution of osteocalcin, degree of mineralization, and mechanical properties along the length of Cyprinus carpio rib bone

This study examined the spatial distribution of selected biochemical and mechanical properties along the length of carp rib bone. Carp rib bone was chosen because of its unusually high osteocalcin content relative to other extractable proteins. The amount of osteocalcin was significantly lower (p<0.01) at the most distal section, relative to all other sections. The amount of phosphate (p<0.05) and the elastic modulus in the longitudinal plane (p<0.0001) were found to be significantly higher in the most distal section, relative to the most proximal section. There was no significant difference in the calcium distribution, molar Ca/P ratio, or elastic modulus in the transverse plane. It was speculated that the distal section contains less mature bone. The methods illustrate the potential usefulness of nanoindentation to characterize the mechanical properties of bone, relative to its biochemical composition. © 2001 Kluwer Academic Publishers     

The effects of accumulated timing jitter on some sine wavemeasurements

This paper investigates the effects of accumulated timing jitter on the signal-to-noise ratio (SNR) and on the phase angle measurement of real sine waves. These measurements are done via the Fast Fourier Transform (FFT) method. Accumulated timing jitter occurs when the sine wave is sampled by an unstable clock where the clock periods are randomly changing. Also, accumulated jitter is a problem in ramp-type bases that were often used in sampling oscilloscopes. Expressions for an estimate of the signal-to-noise ratio [SNR_(est.)] and phase variance in terms of the jitter distribution parameters and the number of FFT points (N) are derived. The derived expressions are verified through computer simulations. Finally, a comparison between independent and accumulated jitter is presented     

Effects of some drugs on hepatic glucose 6-phosphate dehydrogenase activity in Lake Van fish (Chalcalburnus tarischii Pallas, 1811)

Inhibitory effects of some drugs on hepatic glucose 6-phosphate dehydrogenase from Lake Van fish (chalcalburnus tarischii pallas, 1811) were investigated. For this purpose, initially liver glucose 6-phosphate dehydrogenase was purified 899-fold in a yield of 46.24% by using 2',5'-ADP Sepharose 4B affinity gel. In order to control the purification of enzyme was done SDS polyacrylamide gel electrophoresis. SDS polyacrylamide gel electrophoresis showed a single band for enzyme. A constant temperature (+4 degrees C) was maintained during the purification process. Enzyme activity was determined with the Beutler method by using a spectrophotometer at 340 nm. Vankomycine, sulfanylamide, sulfanylacetamide, nidazole, ciprofloxacin, amoxicillin and KMnO(4) were used as drugs. These drugs exhibited inhibitory effects on the enzyme. IC(50) values of vankomycine, sulfanylamide, sulfanylacetamide, nidazole, ciprofloxacin, amoxicillin and KMnO(4) were 1.88, 0.037, 0.032, 1.178, 2.26, 643.5 and 0.0002 mM, and the K(i) constants 1.18+/-0.148, 0.119+/-0.021, 0.075+/-0.015, 1.15+/-0.21, 7.69+/-0.67, 1007+/-69, and 0.001+/-0.00022 mM, respectively. While vankomycine and nidazole showed competitive inhibition, others displayed noncompetitive inhibition. K(i) constants and IC(50) values for drugs were determined by Lineweaver-Burk graphs and plotting activity percentage versus [I], respectively.     

The distribution of iron impurity in single-crystal magnesium oxide and some effects on mechanical properties

MgO containing 5000 wt ppm Fe was heat-treated in various ways, so that the Fe was present in solution as Fe²⁺ or Fe³⁺, as precipitates of MgO.Fe₂O₃, or as metallic bcc Fe. Crystals were studied by optical absorption spectroscopy and microscopy. Heating in air at 1400 C converts most of the Fe to Fe³⁺ and some of this is associated with vacancies, particularly at high impurity levels. In crystals containing Fe³⁺, the magnitude of the hardening is relatively about four times less than that in alkali halides containing divalent metallic impurities, where all the impurities are associated with charge-compensating vacancies. Greater hardening is obtained when precipitates of MgO.Fe₂O₃ are present. Precipitates of metallic bcc Fe are formed on heating in hydrogen at temperatures >1000 C; these have the orientation relationships (001)_MgO (001)_Fe and [110]_MgO [100]_Fe.     

The effects of inflation and the time value of money on some inventory systems

The effects of inflation and the time value of money on the optimal policies of the order-level system and the economic lot-size system are examined. Two different inflation rates, one for the internal and the other for the external costs, are assumed. The objective is to minimize the present value of the total costs per unit time.     

Effect of lipid excipients on in vitro pancreatic lipase activity

PURPOSE: To study the effects of two lipid excipients, Peceol and Gelucire 44/14 on the in vitro pancreatic lipase activity. METHODS: A 50 microL reaction mixture, consisting of 45 microL (3H) triolein as the radiolabeled substrate, 2.5 microL Peceol or Gelucire 44/14 (0.05-0.5%), either alone or in combination, 2.5 microL colipase (100 microg/mL), and 2.5 microL pancreatic lipase (1 mg/mL), was incubated for 10 min at room temperature. At the end of incubation, the reaction was stopped by the addition of an extraction solvent containing chloroform, methanol, and n-heptane (12.5:14:10), and the mixture vortexed briefly. Subsequently, 250 microL of 50 mM sodium carbonate was added and the aqueous and organic phase separated by centrifugation for 5 min at 1000 g. One hundred microliters of the supernatant was transferred to a scintillation counter and then radioactivity measured after the addition of 3.6 mL of scintillation fluid. Pancreatic lipase activity was determined by measuring the amount of free fatty acid released into the incubation medium and expressed as micromol free fatty acid released/min. RESULTS: When used alone, Peceol inhibited the pancreatic lipase activity significantly in a concentration-dependent manner, with a maximum inhibition of 57% at 0.4% of the excipient [p < 0.05, one-way analysis of variance (ANOVA)]. Similarly, Gelucire 44/14 alone caused inhibition of lipase activity in a concentration-dependent manner. However, the maximum inhibition (30%) was smaller in magnitude compared with the former agent. When the two excipients were used in combination, the inhibitory effects on the enzyme activity were similar to those observed with the individual agents (p < 0.05, one-way ANOVA). However, the maximum inhibition of 30% was lower than that observed with Peceol alone. CONCLUSIONS: The results from this study suggest that these lipid excipients inhibit in vitro pancreatic lipase activity and should be taken into consideration when developing oral formulations using these agents.     

Effects of dental resin metabolites on estrogenic activity in vitro

Three monomers (Bis-GMA, UDMA, and TEGDMA) and five polymerization initiators (CQ, BPO, DMPT, DMAEMA, and ATU) commonly used in dental composite resins were tested for estrogenic activity using a reporter gene assay (yeast two-hybrid system) in vitro, and compared with bisphenol-A (BPA). Estrogenic activity was indicated by agonist and antagonist activity, with (+S9) and without (–S9) metabolic activation using rat liver cells. No estrogenic agonist activity was seen for each monomer and polymerization initiator in either the –S9 and +S9 tests in the concentration ranges examined in this study. On the other hand, estrogen antagonist activity was found with BPO and DMPT. BPO showed antagonist activity at a concentration of 1800 nM with the –S9 test, but not with the +S9 test. With DMPT, antagonist activity was not seen with the –S9 test, but it was seen at a concentration of 610 nM using the +S9 test. With BPA, the +S9 test indicated antagonist activity at a concentration of 780 nM. The estrogen antagonist activities of DMPT and BPA appeared to be similar. CQ, DMAEMA, ATU, and the three monomers did not show antagonist activity as demonstrated by the –S9 or +S9 tests within the concentration range tested in this study.     

The effects of some physico-chemical factors and pharmaceutical excipients on the bioavailability of nitrofurantoin oily and aqueous suspensions in rats

The effects of some physico-chemical factors and various excipients, i.e., sucrose, aluminum stearate, hydrogenated castor oil, Cab-o-sil, and lecithin, either alone or in combination, from suspensions in fractionated coconut oil and distilled water have been investigated. In vitro drug release studies were performed according to the flask-stirrer method. In addition to adsorption and solubility studies, determination of partition coefficients and rheological measurements have been carried out. The experimental design was based on an 8×8 latin square using rats as the test animals. The results of the study showed that the rate and extent of absorption of nitrofurantoin are decreased significantly by the use of an oily rather than an aqueous vehicle. In vitro drug release data showed some correlation with in vivo parameters, and also with the apparent viscosity of the vehicles. However, no correlation was detectable between in vivo parameters and the apparent viscosity of the vehicles.     

The buckling of composite stiffened plates with some emphasis on the effects of fibre orientation and on loading configuration

The bucking characteristics of some composite stiffened plates are determined in this paper using a finite strip approach. The finite strip formulation is able to predict the complex buckling modes associated with in-plane shear loading and the method of approach can allow for other loading configurations whose associated pre-buckling stresses are not so obviously realised.

Two loading conditions have essentially been considered in the paper, that of in-plane shear and that of partial edge loads being reacted by shear. The strip displacement fields before and after buckling are represented by algebraic polynomials across the strip and trigonometric functions along the strip length. The inclusion of sufficient harmonics in the appropriate displacement representations thus allows the distorted nodal lines of the shear buckling mode and the complex pre-buckled stresses associated with partial edge loads to be determined with relative ease.     

The mechanical properties of lettuce: A comparison of some agronomic and postharvest effects

Mechanical properties data of Iceberg lettuce leaves are described in relation to the applied agronomic variables and post-harvest treatment. Leaf tissue strength and stiffness were both reduced significantly in plants grown with 120 kg/ha applied nitrogen compared with plants grown with 0 kg/ha applied nitrogen. Leaf tissue strength and stiffness were increased significantly in plants grown with added calcium at 80 kg/ha. Significant reductions in stiffness and increases in failure strain were associated with reduced hydration. These findings show that agronomy changes in mechanical properties are as large as maturity and post harvest induced turgor changes, which has implications for both quality and damage of cut salads.     

Synergetic effects of nanoporous support and urea on enzyme activity

We report synergetic effects of functionalized mesoporous silica (FMS) and urea to promote favorable protein conformational changes. The specific activity of glucose isomerase (GI) entrapped in FMS in the presence of urea was approximately double that of GI in solution in the absence of urea. Rather than losing all activity in a denaturing solution of 8.0 M urea, the specific activity of GI entrapped in FMS remained higher than the highest specific activity of GI free in solution.     

pH effects on collagen fibrillogenesis in vitro: Electrostatic interactions and phosphate binding

Collagen self-assembly in vitro was conducted in the pH range from 6.0 to 10.5 at 30 °C in order to investigate the electrostatic interactions that occur during fibril formation. A sigmoidal curve was observed in the growth rate of fibrils. Collagen fibril morphologies imaged by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) present bundling of fibrils with a small amount of non-fibrillar collagen. At a low pH of 6.6, collagen molecules form small fibrils with a diameter of 85 nm. In the pH range from 6.9 to 8.0, they form fibrils with a diameter of approximately 200 nm, even though the rate of fibrillogenesis accelerates with increasing pH in this range. Zeta potential measurements of soluble collagen indicate that the net surface charge of collagen molecules is not only affected by the pH of medium but also by the presence of added salts. The acceleration of fibrillogenesis rate with increasing pH from 6.6 to 9.2 is consistent with a reduction of surface net charge since the isoelectric point of soluble collagen is approached. The native D-periodicity of 62 nm was found except at pH 7.1 where collagen molecules form short banding of 50–60 nm in the early stage of fibrillogenesis which might be caused by an unusual alignment of collagen molecules in fibrils.     

In vitro antifungal activity and toxicity of itraconazole in DMSA-PLGA nanoparticles

Itraconazole (ITZ) is a drug used to treat various fungal infections and may cause side effects. The aim of this study was to develop and evaluate the in vitro activity of DMSA-PLGA nanoparticles loaded with ITZ against Paracoccidioides brasiliensis, as well as their cytotoxicity. Nanoparticles were prepared using the emulsification-evaporation technique and characterized by their encapsulation efficiency, morphology (TEM), size (Nanosight) and charge (zeta potential). Antifungal efficacy in P. brasiliensis was determined by minimal inhibition concentration (MIC), and cytotoxicity using MTT assay. ITZ was effectively incorporated in the PLGA-DMSA nanoparticles with a loading efficiency of 72.8 +/- 3.50%. The shape was round with a solid polymeric structure, and a size distribution of 174 +/- 86 nm (Average +/- SD). The particles were negatively charged. ITZ-NANO presented antifungal inhibition (MIC = 6.25 ug/mL) against P. brasiliensis and showed lower in vitro cytotoxicity than free drug (ITZ).     

Estrogenic activity of chemicals for dental and similar use in vitro

The estrogenic activities of chemicals for dental and similar use were tested by a reporter gene assay (yeast two-hybrid system) and an estrogen/estrogen receptor (ER-) competition binding assay (fluorescence polarization system). Among the 10 chemicals [bisphenol-A (BPA), bis-2-hydroxypropyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), dibutyl phthalate (DBP), n-butyl benzyl phthalate (BBP), n-butyl phthalyl n-butyl glycolate (BPBG), di-2-ethylhexyl phthalate (DEHP), and di-2-ethylhexyl adipate (DOA)], which were diluted with DMSO to concentrations ranging from 5 × 10^-7 to 5 × 10^-3M, and 17-estradiol (E2) as a positive control, BPA and BBP showed estrogenic activity in these two assays, while the remaining eight chemicals did not at the concentrations tested. Additional data, together with in vivo and epidemiological examinations, are required. Such investigations should also provide information on the validity of these methods for testing the estrogenic activity of chemicals.     

Sustained release effects of berberine-loaded chitosan microspheres on in vitro chondrocyte culture

The low bioavailability and short biological half-life of berberine chloride (BBR) negatively affect the protective role of this compound against osteoarthritis (OA). The present study was performed to evaluate the effectiveness of sustained BBR release system. Novel BBR-loaded chitosan microspheres (BBR-loaded CMs) were successfully synthesized using an ionic cross-linking method for sustained release. The basic characteristics of the prepared microspheres were subsequently evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) techniques, encapsulation efficiency (EE), and in vitro release experiments. BBR-loaded CMs displayed spherical forms to encapsulate a considerable quantity of BBR (100.8?±?2.7?mg/g); these microspheres also exhibited an ideal releasing profile. The FT-IR spectra and XRD results revealed that BBR-loaded CMs were successfully synthesized via electrostatic interaction. In vitro experiments further showed that BBR-loaded CMs significantly inhibited sodium nitroprusside (SNP)-stimulated chondrocyte apoptosis as well as cytoskeletal remodeling, and led to increasing mitochondrial membrane potential and maintaining the nuclear morphology. BBR-loaded CMs exerted markedly higher anti-apoptotic activity in the treatment of OA, and markedly inhibited the protein expression levels of caspase-3, a disintegrin, and metalloproteinase with thrombospondin motifs (ADAMTS)-5 and matrix metalloproteinase (MMP)-13 induced by SNP in rat articular chondrocytes, compared with free BBR at equivalent concentration. Therefore, novel BBR-loaded CMs may offer potential for application in the treatment of OA.     

Assay of in vitro osteoclast activity on dentine,and synthetic calcium phosphate bone substitutes

Resorption of synthetic bone substitute materials is essential for the integration of these materials into the natural bone remodeling process. Osteoclast behavior in the presence of calcium phosphate bioceramics (CaPB) is partially understood, and a better understanding of the underlying mechanisms is expected to facilitate the development of new synthetic bone substitutes to improve bone regeneration. In the present study, our aim was to investigate osteoclastic resorption of various synthetic CaPB. We used neonatal total rabbit bone cells to generate osteoclasts. Osteoclast-generated resorption on dentine and multiple CaPB was investigated by quantifying the surface resorbed and measuring tartrate resistant acid phosphatase (TRAP) enzyme activity. In this study, we observed that osteoclastic cells responded in a different way to each substrate. Both dentine and CaPB were resorbed but the quantitative results for the surface resorbed and TRAP activity showed a specific response to each substrate and that increased mineral density seemed to inhibit osteoclast activity.     

The in vitro effects of semiconductor laser irradiation on inflammation: laser irradiation did not affect monocyte infiltration

The effects of supernatants following irradiation of lymphocytes and monocytes with a semiconductor laser, on monocyte chemotaxis were investigated in vitro. Human peripheral lymphocytes and monocytes were obtained from healthy adult donors, and were suspended in medium, following laser irradiation. The laser irradiation (wavelength 900 nm, output power 1.5 mW) was carried out in the pulse wave mode at doses of 0.1 J cm^-2 in total. After irradiation, the lymphocytes and monocytes were incubated with or without several kinds of stimulants for varying time periods. The supernatants of these cultures were then assayed for human monocyte chemotaxis. Through these experiments, we were unable to detect any significant levels of stimulative or depressive effects due to laser irradiation of the lymphocytes and monocytes, on the production of monocyte chemotactic activity.