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1.
Sci Rep ; 14(1): 7728, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38565584

ABSTRACT

Ecofriendly and stable Fuel Microemulsions based on renewable components were prepared through solubilizing ethanol in diesel and waste cooking oil blend (4:1). New diquaternary ammonium ionic liquids (3a & 3b) were synthesized through a quaternization reaction of the synthesized dihaloester with diethyl ethanolamine tridecantrioate and triethyl amine tridecantrioate, respectively. The chemical structures were elucidated by NMR spectroscopy. It was observed from DLS analyses that the ethanol particles in all samples have sizes between 4.77 to 11.22 nm. The distribution becomes narrower with the decrease in the ionic liquid concentrations. The fuel properties fall within the ASTM D975 acceptable specifications and are close to the neat diesel properties. The Cetane index were 53 and 53.5, heating values were 38.5 and 38.5 MJ/kg, viscosities were 2.91 and 2.98 mm2/s, densities were 8.26 and 8.29 g/mL and flash points were 49 °C and 48 °C for 3a1 and 3b1 microemulsions, respectively. The particle sizes of samples were examined by DLS for 160 days and they were significantly stable. The amount of ethanol solubilized increases with the increase in the amount of the synthesized ionic liquids and cosurfactant. The combustion calculations pointed out that the microemulsions 3a1 and 3b1 need 13.07 kg air/kg fuel and 12.79 kg air/kg fuel, respectively, which are less than the air required to combust the pure diesel. According to theoretical combustion, using ionic liquids saves the air consumption required for combustion and reduces the quantities of combustion products. The prepared microemulsions were successfully used as a diesel substitute due to their improved combustion properties than pure diesel and low pollution levels.

3.
RSC Adv ; 11(52): 33017-33026, 2021 Oct 04.
Article in English | MEDLINE | ID: mdl-35493590

ABSTRACT

The mazout properties were improved using ecofriendly ways because of its wide range of applications, abundance and low cost. In this study, the effect of biodiesel blending on the properties of mazout was investigated. Biodiesel was prepared from waste cooking oil. The mazout properties such as viscosity and density improved with the increase in volume ratio of biodiesel to mazout. The mazout viscosity decreases with an average value of 12% as the biodiesel is added with a volume ratio of 10%. In contrast, when a 10% volume ratio of the biodiesel is added to mazout, the heating value decreases by 1.5%. Although the calorific value of mazout decreases after the blending process, the blending method is considered a method that saves energy compared to the heating method to reduce the viscosity. The cost of improved mazout depends on the cost of biodiesel production. The more the cost of biodiesel production approaches the cost of mazout, the more expensive the use of the blending method compared to the heating method. Moreover, the blending method is a very effective method to reduce the percentages of harmful compounds such as sulfur, and the compound percentages that occupy volumetric proportions of fuel such as water content.

4.
J Appl Stat ; 47(2): 354-375, 2020.
Article in English | MEDLINE | ID: mdl-35706520

ABSTRACT

This paper introduces a new two-parameter exponentiated discrete Lindley distribution. A wide range of its structural properties are investigated. This includes the shape of the probability mass function, hazard rate function, moments, skewness, kurtosis, stress-strength reliability, mean residual lifetime, mean past lifetime, order statistics and L-moment statistics. The hazard rate function can be increasing, decreasing, decreasing-increasing-decreasing, increasing-decreasing-increasing, unimodal, bathtub, and J-shaped depending on its parameters values. Two methods are used herein to estimate the model parameters, namely, the maximum likelihood, and the proportion. A detailed simulation study is carried out to examine the bias and mean square error of maximum likelihood and proportion estimators. The flexibility of the proposed model is explained by using four distinctive data sets. It can serve as an alternative model to other lifetime distributions in the existing statistical literature for modeling positive real data in many areas.

5.
Sci Rep ; 9(1): 18196, 2019 12 03.
Article in English | MEDLINE | ID: mdl-31796792

ABSTRACT

Habitat loss and fragmentation causes a decline in insect populations. Odonata (both dragonflies and damselflies) are especially threatened by the destruction of both aquatic and terrestrial environment. Moreover, effects of large-scale habitat heterogeneity on Odonata assemblages are poorly studied. In a two years study along East-European lowland watercourses both aquatic and terrestrial environment were studied to reveal the importance of local (e.g. water depth, macrovegetation cover, etc.) and landscape-scale (e.g. farmland patch size, forest patch proportion, etc.) variables to Odonata (as well as to dragonflies and damselflies separately) through increasing spatial sampling scales. The specimens were sampled using 500 m long transects from May to September. Results, both on local and landscape scales emphasized the importance of terrestrial environment on Odonata. Local variables influence damselflies, while dragonflies are more sensitive to landscape variables. Damselfly's diversity decreased with increasing macrovegetation cover, while dragonfly's diversity decreased with the increasing degree of land use intensification, but increased with the length of watercourses. It is thus vital to stress the importance of partial watercourse clearing, and moderate maintenance of traditional farm management based on small parcel farming near watercourses to maintain diverse and healthy Odonata assemblages.


Subject(s)
Odonata/physiology , Agriculture/methods , Animals , Biodiversity , Ecosystem , Water
6.
RSC Adv ; 8(66): 37891-37904, 2018 Nov 07.
Article in English | MEDLINE | ID: mdl-35558626

ABSTRACT

The corrosion performance of carbon steel was tested in four polymeric ionic liquids (PILs) that differed only in the fatty acid linked to the chitosan (CS) amine group. The measurements were implemented involved the hydrogen evolution rate (HER), gravimetric measurements, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and quantum chemical estimations. The morphology and the elements arranged on the metal were considered by a scanning electron microscopy (SEM) system attached to an energy dispersive X-ray (EDX) system. The addition of polymeric ionic liquids hindered the rate of hydrogen generation. The order of the inhibitors efficiency was CSPTA-lauric > CSPTA-myristic > CSPTA-palmitic > CSPTA-stearic. The polarization method proved that the percentage inhibition efficiency increases with increasing the inhibitors concentration in 1 M HCl, representing a drop in the corrosion rate of carbon steel. On the other hand, the percentage inhibition decreased with the increase in temperature. Quantum chemical calculations revealed that the tested ionic liquids could react with the iron surface via electron transfer from the metal atom to ionic liquid molecule.

7.
Osteoporos Int ; 26(3): 921-30, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25524020

ABSTRACT

UNLABELLED: We studied bone turnover markers (BTM) and bone microarchitecture (using high-resolution peripheral quantitative computed tomography (HR-pQCT)) in 171 postmenopausal women and their 210 premenopausal daughters. BTM levels correlated positively between mothers and daughters. The mother-daughter pairs with high BTM levels had lower cortical density than those with low BTM levels. INTRODUCTION: We assessed the correlation of serum bone turnover markers (BTM) between postmenopausal mothers and their premenopausal daughters as well as possible determinants of this association and its impact on resemblance of bone microarchitecture between mothers and their daughters. METHODS: Cross-sectional analysis was performed in 171 untreated postmenopausal mothers (54 sustained fragility fractures) and their 210 premenopausal daughters. Intact N-terminal propeptide of type I collagen (PINP) and ß-isomerized C-terminal crosslinking telopeptide of type I collagen (CTX-I) were measured in the fasting status. Bone microarchitecture was assessed using HR-pQCT. RESULTS: After adjustment for age, weight, lifestyle factors, hormones, and mother's fracture status, BTM levels correlated positively between mothers and daughters (Intraclass Correlation Coefficient = 0.22-0.27, p <0.005). Average BTM levels were ∼ 0.6 SD higher among daughters of mothers in the highest BTM quartile vs. the ones in the lowest BTM quartile. The variability of BTM levels explained ≤ 10 and ≤ 14% of variability of bone microarchitecture in the daughters and mothers, respectively. Cortical density was lower by 2.3-2.9% (0.6 SD, p <0.05 to <0.005) in the daughters from the mother-daughter pairs with high BTM levels (defined by generation-specific quartiles) than in the daughters from the pairs with low BTM levels. Corresponding differences for the mothers were 4.5-4.8% (0.5 SD, p <0.05 to <0.01). CONCLUSION: BTM levels correlated between postmenopausal mothers and their premenopausal daughters after adjustment for age, weight, mother's fracture status, lifestyle, and hormonal factors. Family resemblance of BTM levels may contribute to family resemblance of some bone microarchitectural parameters, especially of cortical density.


Subject(s)
Bone Remodeling/genetics , Adult , Aged , Biomarkers/blood , Bone Density/genetics , Bone Density/physiology , Bone Remodeling/physiology , Collagen Type I/blood , Cross-Sectional Studies , Female , Humans , Life Style , Middle Aged , Mothers , Peptide Fragments/blood , Peptides/blood , Postmenopause/blood , Postmenopause/physiology , Premenopause/blood , Premenopause/physiology , Procollagen/blood
8.
J Environ Radioact ; 118: 64-74, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23246704

ABSTRACT

Building materials and their additives contain radioactive isotopes, which can increase both external and internal radioactive exposures of humans. In this study Hungarian natural (adobe) and artificial (brick, concrete, coal slag, coal slag concrete and gas silicate) building materials were examined. We qualified 40 samples based on their radium equivalent, activity concentration, external hazard and internal hazard indices and the determined threshold values of these parameters. Absorbed dose rate and annual effective dose for inhabitants living in buildings made of these building materials were also evaluated. The calculations are based on (226)Ra, (232)Th and (40)K activity concentrations determined by gamma-ray spectrometry. Measured radionuclide concentrations and hence, calculated indices and doses of artificial building materials show a rather disparate distribution compared to adobes. The studied coal slag samples among the artificial building materials have elevated (226)Ra content. Natural, i.e. adobe and also brick samples contain higher amount of (40)K compared to other artificial building materials. Correlation coefficients among radionuclide concentrations are consistent with the values in the literature and connected to the natural geochemical behavior of U, Th and K elements. Seven samples (coal slag and coal slag concrete) exceed any of the threshold values of the calculated hazard indices, however only three of them are considered to be risky to use according to the fact that the building material was used in bulk amount or in restricted usage. It is shown, that using different indices can lead to different conclusions; hence we recommend considering more of the indices at the same time when building materials are studied. Additionally, adding two times their statistical uncertainties to their values before comparing to thresholds should be considered for providing a more conservative qualification. We have defined radon hazard portion to point to the limitations of the internal hazard considerations based on only measured (226)Ra activity concentrations without direct radon measurements. Our data are compared to those obtained in other countries and they provide a good basis to expand the database of radioactivity of building materials and gives information about the safety and situation of the building material industry in this central region of Europe.


Subject(s)
Construction Materials/analysis , Potassium Radioisotopes/analysis , Radiation Monitoring , Radium/analysis , Radon/analysis , Spectrometry, Gamma , Thorium/analysis
9.
Osteoporos Int ; 24(6): 1881-9, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23179577

ABSTRACT

UNLABELLED: We investigated the familial resemblance of bone microarchitecture parameters between postmenopausal mothers with fragility fracture and their premenopausal daughters using high-resolution peripheral quantitative computed tomography (HR-pQCT). We found that daughters of women with fracture have lower total volumetric bone mineral density (vBMD), thinner cortices, and impaired trabecular microarchitecture at the distal radius and tibia, compared to controls. INTRODUCTION: Familial resemblance of areal bone mineral density (aBMD) in mothers and daughters has been widely studied, but not its morphological basis, including microarchitecture. METHODS: We compared aBMD, vBMD, bone size, and bone microarchitecture at the distal radius and tibia assessed by HR-pQCT in mothers and their premenopausal daughters. We included 115 women aged 43 ± 8 years whose mothers had sustained a fragility fracture and 206 women aged 39 ± 9 years whose mothers had never sustained a fragility fracture. RESULTS: Women whose mothers had fracture had significantly (p < 0.05) lower aBMD at the lumbar spine, total hip, femoral neck, mid-distal radius, and ultradistal radius compared to controls. In similar multivariable models, women whose mothers had a fracture had lower total vBMD at the distal radius (-5 %, 0.3 standard deviation [SD]; p < 0.005) and distal tibia (-7 %, 0.4 SD; p < 0.005). They also had lower cortical thickness and area at the distal radius (-5 %, 0.3 SD and -4 %, 0.2 SD, respectively; p < 0.005) and at the distal tibia (-6 %, 0.3 SD and -4 %, 0.3SD, respectively; p < 0.005). Trabecular vBMD was lower at the distal radius (-5 %, 0.3 SD; p < 0.05) and tibia (-8 %, 0.4 SD; p < 0.005), with a more spaced and heterogeneous trabecular network (4 and 7 % at the radius and 5 and 9 %, at the tibia, p < 0.05, for Tb.Sp and Tb.Sp.SD, respectively). CONCLUSION: Premenopausal daughters of women who had sustained fragility fracture have lower total and trabecular vBMD, thinner cortices, as well as impaired trabecular microarchitecture at the distal radius and tibia, compared with premenopausal daughters of women without fracture.


Subject(s)
Bone Density/genetics , Osteoporotic Fractures/genetics , Radius/physiopathology , Tibia/physiopathology , Adult , Aged , Aged, 80 and over , Bone Density/physiology , Cross-Sectional Studies , Female , Humans , Middle Aged , Osteoporotic Fractures/physiopathology , Premenopause/physiology , Radius/diagnostic imaging , Radius/pathology , Tibia/diagnostic imaging , Tibia/pathology , Tomography, X-Ray Computed/methods
10.
Genes Brain Behav ; 7(1): 31-6, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17451452

ABSTRACT

Alpha-synuclein (SNCA) is a key factor in the regulation of dopaminergic transmission and is related to Parkinson's disease. In this study, we investigated the effects of risk and protective SNCA haplotypes associated with Parkinson's disease on cognitive sequence learning in 204 healthy volunteers. We found that the 3'-block risk SNCA haplotypes are associated with less effective stimulus-reward learning of sequences and with superior context representation of sequences. In contrast, participants with protective haplotypes exhibit better stimulus-reward learning and worse context representation, which suggest that these functions are inversely affected by risk and protective haplotypes. The Rep1 promoter polymorphism does not influence cognitive sequence learning. Because stimulus-reward learning may be mediated by the basal ganglia and context learning may be related to the medial temporal lobe, our data raise the possibility that dopaminergic signals regulated by SNCA inversely affect these memory systems.


Subject(s)
Cognition Disorders/genetics , Parkinson Disease/genetics , Polymorphism, Single Nucleotide/genetics , Serial Learning/physiology , alpha-Synuclein/genetics , Adult , Association Learning/physiology , Attention/physiology , Basal Ganglia/physiopathology , Cognition Disorders/diagnosis , Color Perception/physiology , Dopamine/physiology , Female , Genotype , Haplotypes , Humans , Linkage Disequilibrium , Male , Mental Recall/physiology , Middle Aged , Motivation , Neuropsychological Tests , Parkinson Disease/diagnosis , Polymerase Chain Reaction , Promoter Regions, Genetic/physiology , Psychomotor Performance/physiology , Reference Values , Temporal Lobe/physiology
11.
Nahrung ; 48(3): 234-8, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15285119

ABSTRACT

The effect of gamma-irradiation on aflatoxin B1 production by Aspergillus flavus, and the chemical composition of some different crop seeds were investigated. A. flavus infected seeds behaved differently according to their principal constituents. A. flavus caused an increase in protein and decrease in lipids and carbohydrate contents of wheat, soyabean and fababean seeds. Growth of A. flavus and production of aflatoxin B1 was inhibited at a dose level of 5 kGy. A. flavus utilizes carbohydrates of seeds for its growth and aflatoxin production. Crops were arranged, in descending order, according to aflatoxin produced in seeds as wheat > soyabean > fababean. There were no changes in chemical constituents of irradiated seeds, such as protein, lipids, and carbohydrates.


Subject(s)
Aflatoxin B1/biosynthesis , Aspergillus flavus/radiation effects , Food Irradiation , Food Preservation/methods , Gamma Rays , Seeds/microbiology , Aflatoxin B1/analysis , Aflatoxin B1/radiation effects , Aspergillus flavus/metabolism , Consumer Product Safety , Dose-Response Relationship, Radiation , Fabaceae/microbiology , Fabaceae/radiation effects , Humans , Seeds/radiation effects , Glycine max/microbiology , Glycine max/radiation effects , Triticum/microbiology , Triticum/radiation effects
12.
Tumori ; 90(1): 32-5, 2004.
Article in English | MEDLINE | ID: mdl-15143968

ABSTRACT

AIMS AND BACKGROUND: Intraoperative blood loss during liver resection remains a major concern due to its association with higher postoperative complications and shorter long-term survival. The aim of this study was to assess the feasibility and safety of a novel concept for liver resection using a radiofrequency energy-assisted technique. METHODS: From January 2001 to July 2002, 42 patients were operated on using radiofrequency energy-assisted liver resection. Radiofrequency energy was applied along the resection edge to create a 'zone of desiccation' prior to resection with a scalpel. RESULTS: Median resection time was 50 mins (range, 30-110). The median blood loss during resection was 30 mL (range, 15-992). Mean preoperative and postoperative hemoglobin values were 13.7 g/dL (SD +/- 1.6) and 11.8 g/dL (SD +/- 1.4), respectively. No blood transfusion was registered, nor was any mortality observed. There were 3 postoperative complications, one subphrenic abscess, one chest infection and one biliary leak from a hepatico-jejunostomy. Median postoperative stay was 8 days (range, 5-86). CONCLUSIONS: Liver resection assisted by radiofrequency energy is feasible, easy and safe. This novel technique offers a new method for 'transfusion-free' resection without the need for sutures, ties, staples, tissue glue or admission to an intensive care unit.


Subject(s)
Blood Loss, Surgical/prevention & control , Catheter Ablation , Hepatectomy/methods , Adult , Aged , Feasibility Studies , Female , Hepatectomy/adverse effects , Humans , Jejunostomy/methods , Liver Function Tests , Male , Middle Aged , Retrospective Studies , Time Factors , Treatment Outcome
13.
J Thromb Haemost ; 2(6): 940-8, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15140130

ABSTRACT

Fibrinogen Lima is an abnormal fibrinogen with an Aalpha Arg141-->Ser substitution resulting in an extra N-glycosylation at Aalpha Asn139, which seems to be responsible for the impairment of fibrin polymerization. We have studied the polymerization and properties of clots made from both plasma and purified fibrinogen of both the homozygous and heterozygous forms. The clot permeation studies with both plasma and purified protein revealed a normal flux through the network for the heterozygous form but very decreased permeation in the homozygous form. Consistent with turbidity results, the clot network of the homozygous form, seen by scanning electron microscopy, was tight and composed of thin fibers, with many branch points, while the appearance of clots from the heterozygous form was similar to that of control clots, but in both cases the fibers were more curved than those of control clots. The rheological properties of clots from the homozygous form were also altered, with rigidity being increased in plasma clots, but decreased in the purified system, a consequence of the balance between numbers of branch points and fiber curvature. From these results it seems that the extra carbohydrate moiety, located in the alpha coiled-coil region close to the betaC domains, impairs the protofibril lateral association process, giving rise to thinner, more curved fibers, with the structural anomalies being most pronounced in the clots from the homozygous plasma. These studies support a model for fibrin polymerization in which the betaC-betaC interactions are involved in lateral aggregation.


Subject(s)
Fibrin/ultrastructure , Fibrinogen/chemistry , Fibrinogens, Abnormal/genetics , Blood Coagulation/genetics , Fibrinogen/physiology , Glycosylation , Heterozygote , Homozygote , Humans , Microscopy, Electron, Scanning , Permeability , Protein Structure, Tertiary , Rheology
14.
Nahrung ; 47(6): 377-82, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14727763

ABSTRACT

In the present studies trials have been carried out to investigate the occurrence of aflatoxin B1 in the Egyptian cured meat basterma and to control such contamination by gamma-rays. Basterma was prepared from fresh salted meat coated with spice paste and stored at room temperature. The total mould counts of basterma samples varied from 10(3) to 10(6) cfu/g in summer months and from 10(2) to 10(5) cfu/g in winter months. Aspergillus, Penicillium, Mucor, Rhizopus, Fusarium and Cladosporium were the most common fungal genera isolated from basterma samples and its components. Basterma samples contained total aflatoxins at levels from 2.8 to 47 microg x kg(-1). Aflatoxins were determined in the spice paste at levels from 9.6 to 120 microg x kg(-1) and in pepper (285.6 microg x kg(-1)), garlic (224.4 microg x kg(-1)), fenugreek (194.2 microg x kg(-1)), coriander (16 and capsicum (42.4 microg x kg(-1)). At an irradiation dose level of 3 kGy, only one sample each of pepper, fenugreek, and spice paste were contaminated with aflatoxins and all basterma samples and its components were free from aflatoxins at an irradiation dose level of 5 kGy.


Subject(s)
Aflatoxin B1/isolation & purification , Food Irradiation , Fungi/metabolism , Meat Products/analysis , Colony Count, Microbial , Consumer Product Safety , Dose-Response Relationship, Radiation , Food Contamination/prevention & control , Food Microbiology , Fungi/radiation effects , Gamma Rays , Meat Products/microbiology , Spices/analysis , Spices/microbiology
15.
Nahrung ; 46(5): 327-31, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12428447

ABSTRACT

The effect of gamma-irradiation and maize lipids on aflatoxin B1 production by Aspergillus flavus artificially inoculated into sterilized maize at reduced water activity (aw 0.84) was investigated. By increasing the irradiation doses the total viable population of A. flavus decreased and the fungus was completely inhibited at 3.0 kGy. The amounts of aflatoxin B1 were enhanced at irradiation dose levels 1.0 and 1.5 kGy in both full-fat maize (FM) and defatted maize (DM) media and no aflatoxin B1 production at 3.0 kGy gamma-irradiation over 45 days of storage was observed. The level in free lipids of FM decreased gradually, whereas free fatty acid values and fungal lipase activity increased markedly by increasing the storage periods. The free fatty acid values decreased by increasing the irradiation dose levels and there was a significant enhancement of fungal lipase activity at doses of 1.0 and 1.50 kGy. The ability of A. flavus to grow at aw 0.84 and produce aflatoxin B1 is related to the lipid composition of maize. The enhancement of aflatoxin B1 at low doses was correlated to the enhancement of fungal lipase activity.


Subject(s)
Aflatoxin B1/biosynthesis , Aspergillus flavus/radiation effects , Gamma Rays , Lipid Metabolism , Zea mays/chemistry , Aflatoxin B1/radiation effects , Aspergillus flavus/growth & development , Aspergillus flavus/metabolism , Colony Count, Microbial , Dose-Response Relationship, Radiation , Fatty Acids, Nonesterified/metabolism , Food Irradiation , Lipase/metabolism , Lipase/radiation effects , Time Factors , Zea mays/microbiology
16.
Acta Microbiol Pol ; 51(2): 131-7, 2002.
Article in English | MEDLINE | ID: mdl-12363074

ABSTRACT

An experiment was designed to determine the role of the chitinase of S. marcescens in controlling the production of zearalenone by F. graminearum isolated from diseased wheat plants. Fusarium graminearum, F. avenaceum, F. equiseti, F. culmorum, and F. solani were isolated from diseased wheat plant. F. graminearum culture materials were highly pathogenic for wheat seedlings, toxic to ducklings and produced high levels of zearalenone. S. marcescens was grown on the cell wall of F. graminearum and its components, chitin and laminarin as a sole carbon source. The release of N-acetyl-D-glucosamine from chitin, F. graminearum cell wall and living or drying mycelium indicated substrate degradation. S. marcescens applied to F. graminearum infested wheat kernels decreased greatly the occurrence of zearalenone after 4 weeks of incubation. F. graminearum culture materials treated with S. marcescens proved to be non-toxic to ducklings and wheat seed germination.


Subject(s)
Chitinases/metabolism , Fusarium/metabolism , Plant Diseases/microbiology , Serratia marcescens/enzymology , Zearalenone/biosynthesis , Acetylglucosamine/metabolism , Triticum/metabolism , Triticum/microbiology , Zearalenone/metabolism
17.
Phytomedicine ; 9(6): 489-95, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12403156

ABSTRACT

The cancer chemopreventive agent apigenin also has strong cytostatic and anti-angiogenic effects in vitro. We now investigated its efficacy against experimental Lewis lung carcinomas (LLC), C-6 gliomas and DHDK 12 colonic cancers in vivo. Tumour bearing mice received 50 mg/kg/day apigenin in three different galenical formulations during 12 days in 8-hourly intervals. Only weak effects of apigenin on the size and the number of new tumour blood vessels of both established and newly transplanted tumours were recorded although the intratumoural necrosis was elevated (45 +/- 15% vs. 20 +/- 7% (control), p < 0.05%). These results contrast sharply with the high in vitro sensitivity of LLC, C-6, DHDK 12 and endothelial cells to apigenin where complete growth suppression occurs at concentrations beyond 30 g/ml. Possible causes are discussed.


Subject(s)
Antineoplastic Agents/pharmacology , Flavonoids/pharmacology , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/therapeutic use , Apigenin , Cell Division/drug effects , Flavonoids/administration & dosage , Flavonoids/therapeutic use , Glioma/drug therapy , Glioma/pathology , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Nude , Necrosis , Neoplasm Transplantation , Rats , Tumor Cells, Cultured
18.
Nahrung ; 46(2): 118-21, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12017988

ABSTRACT

The effects of UV radiation and nitrosamines on the induction of mycotoxin biosynthesis by some nontoxigenic moulds isolated from feed samples collected from Egypt and Poland was investigated. Nontoxigenic strains of Aspergillus flavus P-63, A. niger EN-200 and A. ochraceus P-157 synthesized mycotoxins (aflatoxins and ochratoxin, A) after exposure to near UV radiation for 120-210 min. Nitrosamines (DMNA and DENA) at 30 up to 1000 ppm induced the synthesis of aflatoxins by nontoxigenic species of A. flavus ES-255 and P-63 and A. niger EN 200. Near-UV radiation and nitrosamines had no influence on the induction of mycotoxin synthesis by Penicillium and Fusarium isolates. All nontoxigenic strains of Aspergilli which synthesized aflatoxins in the presence of 1000 ppm nitrosamines, also synthesized continuously aflatoxins during the next fifteen generations. Near-UV radiation and nitrosamines had a mutagenic effect on the induction of mycotoxins synthesis by nontoxigenic moulds.


Subject(s)
Aspergillus/metabolism , Food Microbiology , Mycotoxins/biosynthesis , Nitrosamines/pharmacology , Ultraviolet Rays , Aspergillus/drug effects , Aspergillus/radiation effects , Fusarium/drug effects , Fusarium/metabolism , Fusarium/radiation effects , Penicillium/drug effects , Penicillium/metabolism , Penicillium/radiation effects , Time Factors
19.
Eur J Biochem ; 268(8): 2416-20, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11298761

ABSTRACT

Conformational changes accompanying P-glycoprotein (Pgp) mediated drug transport are reflected by changes in the avidity of certain monoclonal antibodies (mAbs). More of the UIC2 mAb binds to Pgp-expressing cells in the presence of substrates or modulators [Mechetner, E.B., Schott, B., Morse, S.B., Stein, W., Druley, T., Dvis, K.A., Tsuruo, T. & Roninson, I.B. (1997) Proc. Natl Acad. Sci. USA 94, 12908-12913], while the binding of other mAbs (e.g. MM12.10, MRK16, 4E3) is not conformation sensitive. Pre-staining of Pgp+ cells with UIC2 decreased the subsequent binding of MM12.10 mAb by about 30-40%, suggesting that there are Pgp molecules available for both UIC2 and MM12.10, and others accessible only for MM12.10. In the presence of certain substrates/modulators such as vinblastin, cyclosporin A or valinomycin, the MM12.10 reactivity was completely abolished by preincubation with UIC2. However, verapamil, Tween-80 and nifedipine did not influence the ratio of bound mAbs significantly. This is the first assay to our knowledge, sharply distinguishing two classes of modulators. The conformational changes accompanying the mAb competition phenomenon appear to be closely related, though not identical to those accompanying the UIC2-shift, as suggested by the simultaneous assessment of the two phenomena.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry , Antibodies/metabolism , 3T3 Cells , Animals , Anti-Bacterial Agents/pharmacology , Antibodies, Monoclonal/metabolism , Antineoplastic Agents, Phytogenic/pharmacology , Binding, Competitive , Calcium Channel Blockers/pharmacology , Cyclosporine/pharmacology , Drug Resistance, Neoplasm , Enzyme Inhibitors/pharmacology , Flow Cytometry , Humans , Mice , Nifedipine/pharmacology , Polysorbates/pharmacology , Protein Binding , Protein Conformation , Substrate Specificity , Tumor Cells, Cultured , Valinomycin/pharmacology , Verapamil/pharmacology , Vinblastine/pharmacology
20.
Cancer Detect Prev ; 24(5): 415-21, 2000.
Article in English | MEDLINE | ID: mdl-11129983

ABSTRACT

P-glycoprotein (P-gp) acts as an active efflux mechanism for a large number of cytostatics and seems to be involved in the frequent failure of cancer chemotherapy. The molecular events of substrate recognition and transport still are not understood completely. We show here that the percentage of P-gp epitopes available for labeling with UIC2 monoclonal antibody is increased significantly after methanol permeabilization/fixation of cells. At the same time, binding of the MRK16 and 4E3 anti-P-gp antibodies is changed only moderately. Confocal microscopical images of UIC2-PE-labeled cells show that the epitopes becoming available after fixation are situated mainly in the plasma membrane. Thus, only a minority of P-gp molecules are accessible for UIC2 in the cell membrane of live cells, and methanol treatment can expose a large pool of previously plasma membrane-embedded, cryptic UIC2 epitopes. The UIC2-reactive P-gp molecules do not appear to be sequestered spatially, as suggested by the high fluorescence resonance energy transfer efficiency measured between the fluorescently labeled competing UIC2 and MRK16 antibodies, suggestive of P-gp dimerization and oligomerization on live cells.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , 3T3 Cells , ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry , ATP Binding Cassette Transporter, Subfamily B, Member 1/immunology , Animals , Antibodies, Monoclonal , Cell Membrane/drug effects , Cell Membrane/immunology , Cell Membrane/metabolism , Cell Membrane Permeability/drug effects , Cell Membrane Permeability/immunology , Energy Transfer , Epitopes/metabolism , Fixatives/pharmacology , Flow Cytometry , Fluorescence , Humans , KB Cells , Methanol/pharmacology , Mice , Microscopy, Confocal , Protein Conformation
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