The effects of Al and Ba on the colour performance of chromic oxide green pigment

On the basis of the novel hydrogen reduction of chromite ore, an activated sintering method was devised to prepare chromic oxide green pigment. Using XRD, SEM, EDX, ICP-AES, UV and reflectance colorimetry it was found that the colour performance of the synthesized pigment was markedly improved by adding Al and Ba, which resulted in the formation of an Al₂O₃–Cr₂O₃ solid solution and a secondary BaCr₂O₄ phase, respectively, within the pigment. The colour performance of the chromic oxide green pigment doped with 0.1% Al and 0.55% Ba conformed to commercial pigment standards.     

Comparative hypocholesterolemic effects of six dietary oils in cholesterol-fed rats after long-term feeding

Rats (8 wk of age) fed a conventional diet were shifted to diets containing 10% Oenothera biennis Linn oil (OBLO, linoleic acid +γ-linolenic acid) from a wild plant, evening primrose oil (EPO, linoleic acid +γ-linolenic acid) from a cultivated plant, bio-γ-linolenic acid oil from mold (BIO, palmitic acid+oleic acid+linoleic acid+γ-linolenic acid), safflower oil (linoleic acid), palm oil (PLO, palmitic acid+oleic acid+linoleic acid), or soybean oil (linoleic acid+α-linolenic acid) with 0.5% cholesterol for 13 wk. Though there were no significant differences in the food intake among the groups, the body weight gain of the OBLO group was significantly lower than that of other groups except for the BIO and PLO groups, and that of the EPO and SPO groups were the highest among the groups. The liver weight of the OBLO group was significantly lower than that of other groups, and that of the PLO group was the highest among the groups. The serum total cholesterol and very low density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low density lipoprotein (LDL) cholesterol concentrations of the OBLO and EPO groups were consistently lower than those in the other groups. However, those of the BIO group were higher than those in the OBLO and EPO groups. The liver cholesterol concentration of the PLO group was the highest among all groups except for the EPO group. The fecal neutral sterol and bile acid extraction of the BIO group tended to increase compared to other groups. The results of this study demonstrate that OBLO and EPO inhibit the increasing of serum total cholesterol and VLDL+IDL+LDL-cholesterol concentrations in the presence of excess cholesterol in the diet compared with the other dietary oils.     

Effects of long-term administration of lithium and hydrochlorothiazide in rats

The biochemical and histological changes following 60 days administration of daily doses equivalent to 1/20 LD(50) of lithium lactate and hydrochlorothiazide, as such and in association, were studied in male Wistar rats. No mortality or overt signs of toxicity were observed during the experiment and the serum activities of transaminases, alkaline phosphatase and cholinesterase were not significantly modified compared to controls. The histopathological examination of all the investigated organs: kidney, liver, brain and spleen, revealed significant lesions which were time-dependant and more pronounced in the association group. Although the changes were mostly inflammatory and conqestive, it was proved that the concomitant administration of lithium and hydrochlorothiazid is potentially dangerous, increasing lithium's nephrotoxicity and the thiazide diuretic's hepatotoxicity.     

Clinical and biochemical alterations in rats treated with high doses of vitamin A

In the present work the effect of intramuscular administration of 30.000, 50.000 and 100.000 IU of vitamin A palmitate daily for seven days, respectively, on the liver enzyme activity in 45 white male Wistar rats, aged 12 weeks and weighing 180-200 g, have been studied. The group control was integrated by 15 healthy rats with similar characteristics (strain, gender, age and weight) to treated animals. Food and water consumption and body weights were recorded at the end of the experimental period. Rats were observed for clinical signs of toxicity. At the end of the study, rats were sacrificed under ether anesthesia. Liver samples were taken for the determination of enzyme activity. Administration of excess of vitamin A produced a significant (p < 0.05) increase in the content of liver vitamin A, determined diverse and variable clinical signs (such as, anorexia, loss of body weight, alopecia, conjunctivitis, external and internal hemorrhages, skin abnormalities and death) and increased (p < 0.05) the activity of the following enzymes: alanine aminotransferase, aspartate aminotransferase, acid maltase (acid alpha-1,4-glucosidase), acid proteases, lactate dehydrogenase and alkaline phosphatase while glucose-6-phosphatase, glycogen phosphorylase, alpha-amylase, cholinesterase and arginase decreased (p < 0.05) as compared with untreated controls. These changes depend on the doses given of vitamin A. In conclusion, our results provide evidence that short-term administration of high doses of vitamin A determined diverse and variable clinical signs and produces a marked alteration of activity of liver enzymes.     

Distribution and biocompatibility studies of graphene oxide in mice after intravenous administration

We determined the distribution and biocompatibility of graphene oxide (GO) in mice by using radiotracer technique and a series of biological assays. Results showed that GO was predominantly deposited in the lungs, where it was retained for a long time. Compared with other carbon nanomaterials, GO exhibited long blood circulation time (half-time 5.3 ± 1.2 h), and low uptake in reticuloendothelial system. No pathological changes were observed in examined organs when mice were exposed to 1 mg kg⁻¹ body weight of GO for 14 days. Moreover, GO showed good biocompatibility with red blood cells. These results suggested that GO might be a promising material for biomedical applications, especially for targeted drug delivery to the lung. However, due to its high accumulation and long time retention, significant pathological changes, including inflammation cell infiltration, pulmonary edema and granuloma formation were found at the dosage of 10 mg kg⁻¹ body weight. More attention should be paid to the toxicity of GO.     

Essential fatty acid-deficient rats: III. Distribution of lipid classes in rat testes after feeding partially hydrogenated oils

Total and relative amounts of neutral lipids (NL) and phospholipids (PL) as well as the distribution of various lipid classes in these were determined in testes of rats fed different types of partially hydrogenated oils for 5,15 and 26 weeks. The dietary fats were partially hydrogenated arachis oil (HAO), partially hydrogenated soybean oil (HSO), partially hydrogenated herring oil (HHO) and, for comparison, arachis oil (AO). An additional series of animals was reared on a fat-free diet throughout the entire experiment. The total amount of NL is decreased by EFA deficiency parallel with the development of the degenerative changes of the spermatogenic tissue. The relative amounts of NL in the testis are not influenced by EFA deficiency during the first stages of degeneration. However, feeding of HHO for 26 weeks resulted in a marked decrease in NL. The total content of PL is directly related to tissue degeneration. This observation is supported by the data obtained after 5 weeks of feeding HHO and by the correspondence between the results found after 15 and 26 weeks on HAO and the fat-free diets, respectively. The relative amount of PL is less influenced by EFA deficiency, but severe degenerations as found for the group fed HHO are followed by decreases. The neutral lipids had three main fractions: triglycerides (TG), free fatty acids (FFA) and cholesterol (Chol). FFA was found to be the main fraction of NL after 5 weeks, whereas TG was the main component of NL after 15 and 26 weeks, especially in the animals with degenerated testes. The presence of the large quantities of FFA is discussed. Cholesterol was decreased markedly in the EFA deficient rats fed partially hydrogenated oils, but not in the fat-free reared groups. The variations in the PL distribution during the experiment were small with regard to the two main PL classes, the phosphatidylcholines and the phosphatidylethanolamines. The most remarkable change among the PL classes was an increase in the percentage of sphingomyelins when the spermatogenic degenerations developed.     

Effects of long-term feeding of marine oils with different positional distribution of eicosapentaenoic and docosahexaenoic acids on lipid metabolism, eicosanoid production, and platelet aggregation in hypercholesterolemic rats

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were distributed mainly in the sn-1,3 positions of seal oil triglyceride and in the sn-2 position of squid oil triglyceride. Seal oil-rich or squid oil-rich fats having constant saturated/monounsaturated/polyunsaturated fatty acid (PUFA) and n−6/n−3 PUFA ratios were fed to exogenously hypercholesterolemic rats for 160 d. The control fat contained linoleic acid as the sole PUFA. Before starting the experimental diets, rats were orally treated with high doses of vitamin D for 4 d to accelerate atherogenesis. The percentage of arachidonic acid in phosphatidylcholine and phosphatidylethanolamine of liver, platelets, and aorta was lower in the marine oil groups than in the control group, seal oil being more effective than squid oil. Maximal platelet aggregation induced by collagen was significantly lower both marine oil groups. Platelet thromboxane (TX) A₂ production induced by collagen or thrombin was markedly reduced by feeding seal or squid oils, the reduction being more pronounced in the seal oil than in the squid oil group. Aortic prostacyclin (PGI₂) production was the same among the three groups. The ratio of the productions of aortic PGI₂ and platelet TXA₂ was significantly higher in the seal oil than in the control group. Although there was no difference in intimal thickness among the three groups, the aortic cholesterol content was significantly lower in the marine oil groups than in the control group. These results showed that the main effects in rats of the different intramolecular distributions of EPA and DHA in dietary fats were on arachidonic acid content in tissue phospholipids and on platelet TXA₂ production.     

Distribution of14C after oral administration of (U-14C)labeled methyl linoleate hydroperoxides and their secondary oxidation products in rats

To study the toxicity of low molecular weight (LMW) compounds formed during the autoxidation of oils,¹⁴C-labeled primary monomeric compounds (methyl linoleate hydroperoxides) and secondary oxidation products, i.e., polymer and LMW compounds prepared from autoxidized methyl [U-¹⁴C]linoleate hydroperoxides (MLHPO) were orally administered to rats, and their radioactive distributions in tissues and organs were compared. The polymeric fraction consisted mainly of dimers of MLHPO. For the LMW fraction, 4-hydroxy-2-nonenal, 8-hydroxy methyl octanoate and 10-formyl methyl-9-decenoate were identified as major constituents by gas chromatography-mass spectrometry (GC-MS) after chemical reduction and derivatization. When LMW compounds were administered to rats,¹⁴CO₂ expiration and the excreted radioactivity in urine in 12 hr were significantly higher than those from polymer or MLHPO administration. Maximum¹⁴CO₂ expiration appeared 2–4 hr after the dose of LMW compounds. Radioactivity of the upper part of small intestines six hr after the dose of LMW compounds was higher than the values from administered polymer or MLHPO. The remaining radioactivity in the digestive contents and feces 12 hr after administration of LMW compounds was much lower than the values observed from administered polymer or MLHPO. Among internal organs, the liver contained the highest concentration of radioactivities from polymer, MLHPO and LMW fractions, and an especially higher level of radioactivity was found in liver six hr after the administration of LMW compounds. Six hours after the dose of LMW compounds, a relatively higher level of radioactivity also was detected in kidney, brain, heart and lung. These results show that the LMW compounds from MLHPO autoxidation are more easily absorbed in rat tissues than polymer and MLHPO.     

Hypolipidemic effects of clofibrate and selected chroman analogs in fasted rats: I. Chow-fed animals

The hypolipidemic properties of ethyl 6-chlorochroman-2-carboxylate (II), ethyl 6-phenylchroman-2-carboxylate (III) and ethyl 6-cyclohexylchroman-2-carboxylate (IV) were compared to clofibrate (I) in fasted normolipidemic rats. The chroman analog II, like its parent compound, clofibrate, reduced serum and α-lipoprotein cholesterol concentrations. Although analog III had no effect on serum cholesterol, it caused a slight elevation of α-lipoprotein cholesterol concentration. Serum free cholesterol was increased and LCAT activity was reduced in clofibrate-treated rats. The hypolipidemic agents had no consistent effect on liver lipid concentrations and liver microsomal HMG-CoA reductase activity. In addition, we have shown that drug efficacies varied directly with seasonal variations in serum lipid concentrations.     

Absence of E. coli regrowth after Fe and TiO2 solar photoassisted disinfection of water in CPC solar photoreactor

Field disinfection of water in a large solar compound parabolic collector (CPC) photoreactor (35–70 l) was conducted at 35 °C by different photocatalytic processes: sunlight/TiO₂, sunlight/TiO₂/Fe³⁺, sunlight/Fe³⁺/H₂O₂ and compared to the control experiment of direct sunlight alone. Experiments were carried out using a CPC and natural water spiked with E. coli K 12. Under these conditions, total disinfection by bare sunlight irradiation was not reached after 5 h of treatment; and bacterial recovery was observed during the subsequent 24 h in the dark.

The addition of TiO₂, TiO₂/Fe³⁺ or Fe³⁺/H₂O₂ to the water accelerates the bactericidal action of sunlight, leading to total disinfection by solar-photocatalysis. No bacterial regrowth was observed during 24 h after stopping sunlight exposure. For some samples, the decrease of bacteria continues in the dark. A “residual disinfection effect” was observed for these samples before reaching the total inactivation. The effective disinfection time (EDT₂₄), defined as the treatment time required to prevent any bacterial regrowth during the subsequent 24 h in the dark, after stopping the phototreatment, was reached in the presence but not in the absence of different photocatalytic systems. EDT₂₄ was 2 h 30 min, 2 h and 1 h 30 min for sunlight/TiO₂, sunlight/TiO₂/Fe³⁺ and sunlight/Fe³⁺/H₂O₂ systems, respectively. The post irradiation events observed when the phototreated water is poured into an optimal growth medium are also discussed.