The aim of this study was to evaluate if the carotenoid content of Italian tomatoes is affected by factors such as the geographical area in which the plants are cultivated, harvest time, tomato typology and ripening stage. Three Italian tomato varieties were sampled in different geographical locations throughout Italy in the summer and winter months. Significant differences were found in the lycopene, beta-carotene and phytoene contents as a function of tomato variety with the highest carotenoid levels recorded for cherry tomatoes. In relation to the geographic location the only significant differences were lycopene content in salad tomatoes. The harvesting period influenced carotenoid composition, but a definite seasonal trend was not observed. During the summer the lycopene content was higher in summer-harvested tomatoes than in winter-harvested ones, for both cluster and cherry typologics. In relation to the harvesting season, no significant differences were found for the lycopene content in salad tomatoes, while the beta-carotene content was significantly different. Ripening stage influenced lycopene and carotene levels in all the varieties considered; significant differences in the phytoene values were found in cherry tomatoes. The highest carotenoid levels were recorded in fully ripe cherry tomatoes.

In insects, developmental responses are organ- and tissue-specific. In previous studies of insect midgut cells in primary tissue cultures, growth-promoting and differentiation factors were identified from the growth media, hemolymph, and fat body. Recently, it was determined that the mitogenic effect of a Manduca sexta fat body extract on midgut stem cells of Heliothis virescens was due to the presence of monomeric alpha-arylphorin. Here we report that in primary midgut cell cultures, this same arylphorin stimulates stem cell proliferation in the lepidopterans M. sexta and Spodoptera littoralis, and in the beetle Leptinotarsa decemlineata. Studies using S. littoralis cells confirm that the mitogenic effect is due to free alpha-arylphorin subunits. In addition, feeding artificial diets containing arylphorin increased the growth rates of several insect species. When tested against continuous cell lines, including some with midgut and fat body origins, arylphorin had no effect; however, a cell line derived from Lymantria dispar fat body grew more rapidly in medium containing a chymotryptic digest of arylphorin.

ABSTRACT The aim of this study was to consider the problem of residual drugs in cow's milk and to define the influence of such residues in the milk coagulation process, including the case in which the concentration is below the lowest limits permitted by law. Compounds that have EU maximum residue levels (MRLs) were selected. Through milk dynamographic analysis, the chemical and rheological parameters (r, k20 and a30) were determined in relation to the different quantities of drug additions. Effects on coagulation were demonstrated for high concentration. The only residue that demonstrated significant effects at MRL value was trimethoprim. These results were confirmed using electron microscopy, rheological studies and near‐infrared spectral analysis.

Recent studies have shown that Bombyx mori larval midgut can transport proteins unaltered following the transcellular pathway by transcytosis. The numerous steps involved in this complex process are still unknown in the insect midgut, and a promising tool to elucidate this aspect is the availability of single midgut cells in culture suitable for transport experiments. Mature midgut cells in culture were obtained from stem cells isolated from B. mori larvae cultured in Grace's medium supplemented with 20-hydroxyecdysone (20-HE) and a-arylphorin. After three weeks, up to 60 % of the cultured cells were differentiated into columnar and goblet cells, the two predominant cell types in the midgut epithelium. These cells presented in vitro the same shape, morphology and polarity recorded in vivo, even if their dimensions were slightly reduced. Columnar cells displayed a well developed cytoskeletal arrangement, with actin filaments highly organized within the thick brush border and distributed in faint filaments in the cell cytoplasm. Microtubules formed a substantial net just beneath the brush border and ran longitudinally from the apical to the basal pole of the cell. Cultured cells homogenates displayed aminopeptidase N and alkaline phosphatase activity, proving that these two enzymes, involved in vivo in the intermediate and final digestion, are expressed also in vitro. The columnar cells differentiated in culture were able to internalize two model proteins with quite different transport rates.

In this paper, we applied an NMR methodology based on the analysis of selective spin–lattice relaxation rate enhancements of ligand protons induced by interaction processes between prednisolone and a synthetic copolymer, namely poly(N-isopropylacrylamide-co-N-acryloil-l-phenylalanine), in order to investigate this system as a model for studying drug–biomacromolecules interactions. The contribution from the bound ligand fraction to the observed relaxation rate in relation to macromolecule concentration allowed the calculation of the normalized affinity index [AIN]LT, in which the effects of motional anisotropies and different proton densities have been removed. This parameter, which represents the global affinity of the ligand towards the macromolecule, isolates the contribution due to a decrease in the ligand dynamics caused by the binding with the copolymer. The affinity index calculated for prednisolone–copolymer complex compared to that obtained for prednisolone–albumin system, suggested that synthetic polymers as models of biomacromolecules can play an important role in drug–protein interaction studies.

Proton NMR selective and non-selective spin-lattice relaxation rate measurements were used to monitor the strength of the overall complexation behaviour of a ligand (carbamazepine) toward a macromolecular receptor (albumin). The 'affinity index,' a quantitative parameter related to the strength of the ligand-macromolecule interaction, was determined from the experimental contribution of the bound ligand molar fraction to the observed selective spin-lattice relaxation rate. The effect of a second ligand (lamotrigine) on the carbamazepine-albumin interaction was also investigated and was found to have a modulation effect on the carbamazepine-albumin interaction. Copyright (C) 2001 John Wiley & Sons, Ltd.

An efficient and sensitive liquid chromatographic method is described for the determination of the anthelminthic drug levamisole, in muscle, liver, kidney and fat of sheep, pigs and poultry, using thiabendazole as internal standard. Samples were extracted by homogenizing with chloroform, and were applied to Supelco Si solid-phase extraction columns and eluted with methanol. Chromatographic analysis was performed on a LiChrospher 60 RP-Select B column using methanol/ammonium acetate buffer 0.05 M (55/65, v/v) as mobile phase and reading at 220 nm. The quantification limit for the assay was 4 ng/g. Mean recoveries were about 84% for liver, 85% for kidney, 89% for muscle and 84% for fat. The assay has been used for statutory testing purposes.

Two chromatographic methods were developed for the determination of erythromycin A (EA) residues in animal tissues (muscle, liver, kidney and fat of cattle, pigs and poultry) and cow's milk. In addition to a more traditional method using electrochemical detection, we developed an original alternative method based on UV detection at 236 nm, by pretreating to create a chromophore in the molecule. An internal standard was used with both methods to check the variability of the analytical system. Analysis times and performance were compared. The recovery of EA from various matrices was greater than 95%. For both methods the quantification limit for EA was 0.25 microgram ml-1 for plasma, 0.025 microgram g-1 for milk and 0.125 microgram g-1 for the other biological matrices. The methods can be used to check for EA residues in these matrices; in fact, the statutory maximum residue limits (MRLs) of EA are 0.4 microgram g-1 in muscle, kidney, liver and fat of beef cattle, sheep, pigs and poultry, and 0.04 microgram g-1 in cow's and sheep's milk.

The influence of diethyleneglycol monoethyl ether (transcutol), alone or in combination with propylene glycol, on clonazepam permeation through an artificial membrane and excised rabbit ear skin from Carbopol hydrogels was investigated. Drug kinetic permeation parameters were determined for both series of experiments and compared. Rheological characteristics, drug solubility and membrane/vehicle partition coefficient for each gel formulation were also determined, and their role in the formulation performance was investigated. Both series of experiments showed an increase of drug permeation as a function of transcutol content in the formulation. The combination of transcutol and propylene glycol resulted in a synergistic enhancement of clonazepam flux. A different trend was found in experiments with gels containing mixtures of the two enhancers, where an increase (in the case of artificial membrane) or a decrease (in the case of rabbit ear skin) of drug permeation was found by increasing the transcutol/propylene glycol ratio in the mixture. Such a result is explained on the basis of the particular mechanism of action demonstrated for transcutol which associates the increase of drug solubility to the potent effect of a depot in the skin.

The ligand–macromolecule interaction is analysed in terms of selective (R1SE) and non-selective (R1NS) spin–lattice relaxation rates, considering the contribution arising from all possible specific and non-specific receptor sites. A linear relation between ΔR1SE and macromolecule concentration is demonstrated to exist under any coordination conditions. The slope of the straight line obtained is defined as the `affinity index' which is proposed as a general criterion for assessing the total ability of a ligand to interact with a macromolecule.

The recent commercial availability of near infrared spectrometric instruments for the transmittance analysis of solids makes it possible to analyse solid drugs in their finished form. Application of the method to the control of the assay of the active ingredient in diphenhydramine tablets gave results comparable to those obtained in reflectance mode with whole and milled tablets.

Irganox 1330 (1,3,5-trimethyl-2,4,5-tris(3',5'-ditert-butyl)-4'-hydroxybenzyl)- benzene) (I), an alkylphenol compound used as antioxdiant in the production of high density polyethylene (HDPE), was the subject of this study. The quantity of I given up by polyethylene samples of different thickness to aqueous and lipophilic media simulating food was studied by planar chromatography (PC). The manner of antioxidant release was also investigated. The chromatographic method developed was found satisfactory for the quantification of I in the migration studies undertaken, and had quantification limits (12 ng/deposit) suitable for quality control of HDPE.

The near infrared reflectance spectra of the skin of atopic and normal subjects were compared after topical application of perfluorinated polyethers (fomblins) of different molecular weight and viscosity. It was possible to distinguish the two classes of subjects and the different fomblins applied, by principal components analysis.

A diffusion cell with an artificial membrane and the single-pass perfused rabbit ear were used to evaluate the percutaneous absorption of clonazepam from various 2-hydroxyethyl acetate (HEA) patches. The influence on drug permeation of the various type of enhancers (isopropylmyristate, lauryl alcohol, propylene glycol and water) in the patches was tested. A comparison between the two types of systems of percutaneous absorption of clonazepam has been done. The results showed that HEA patches produce controlled uniform drug release, modulated by the addition of enhancers.

The results of an investigation of the transfer of calibration in near-infrared reflectance spectrometry are reported. Four approaches were tested: direct standardization, direct standardization combined with principal components analysis, ordinary least squares and slope/intercept correction. These approaches were used on two different systems, laboratory samples and industrial samples, for which qualitative and quantitative calibrations had been developed previously. After standardization, the standard error obtained was substantially reduced with respect to the original spectra.

An ‘affinity index’, representing the global affinity between a ligand and a biomacromolecular receptor, is proposed. It is determined as the slope of the linear relations between ΔR1SE and the receptor concentration and has the advantage of providing a measure of the ligand-biomacromolecule global affinity which is independent of the number of interaction sites. The method was applied to the calculation of the lamotrigine-albumin affinity index.

An investigation into the existence of spectral differences and differences in response in terms of water and lipid content between normal and atopic skin is described. Since NIR radiation penetrates complex structured matrices down to a depth of 0.15-0.20 mm, it is evident that the method lends itself to spectral detection of skin components down to the deepest level. First the reproducibility of readings made with the instrument was tested and it was also checked whether the use of the probe caused changes in skin equilibrium due to occlusion. Analysis of the NIR spectra did not enable normal and atopic subjects to be distinguished unequivocally but provided important information on the use of NIR spectrometry in these subjects and insights into the stratum corneum. Although the responses of water and lipid structures could not be read directly from the spectra, it was possible to decompose the global spectral information into components by principal components analysis. It was possible to observe a fraction of variance associated in different ways with water.

Within a wide study designed to the development of a transdermal delivery system of clonazepam, in the present work the in vitro permeation behaviour of the drug from a series of alcoholic-gel or emulsion-gel formulations containing various enhancing agents was investigated. Physicochemical properties of each gel and drug kinetic permeation parameters were determined. The flux of the drug was found to be principally influenced by both the drug solubility in the vehicle and the formulation viscosity. The results indicated the great importance of a proper choice of the vehicle for optimization of drug delivery. The formulations containing isopropanol gave the best results, yielding a flux of clonazepam up to four times greater than in the absence of enhancer.

An investigation into the existence of spectral differences and differences in response in terms of water and lipid content between normal and atopic skin after interaction with chemical agents is described. Three compounds were taken as models: a prevalently hydrophilic solvent (polyethylene glycol, PEG 400), a prevalently lipophilic solvent (isopropyl myristate) and a hydrophilic pharmaceutical (gel) used to promote contact in electrocardiography. Using principal component analysis it was possible to distinguish atopic and normal subjects by simple contact of the skin with chemical agents.