Cavernous hemangioma of the thyroid

Most current vascular alterations of the thyroid are connected with the organization of a thyroid hematoma after fine-needle aspiration (FNA). Cavernous hemangioma is a benign congenital vascular malformation that occasionally affects the thyroid. This article presents two cases of this rare thyroid pathology unrelated to FNA.

Determination of nonsteroidal anti-inflammatory drugs in biological fluids by automatic on-line integration of solid-phase extraction and capillary electrophoresis

A new, automatic method for the clean-up, preconcentration, separation, and quantitation of nonsteroidal anti-inflammatory drugs (NSAIDs) in biological samples (human urine and serum) using solid-phase extraction coupled on-line to capillary electrophoresis is proposed. Automatic pretreatment is carried out by using a continuous flow system operating simultaneously with the capillary electrophoresis equipment, to which it is linked via a laboratory-made mechanical arm. This integrated system is controlled by an electronic interface governed via a program developed in GWBasic. Capillary electrophoresis is conducted by using a separation buffer consisting of 20 mM NaHPO4, 20 mM beta-cyclodextrin and 50 mM SDS at pH 9.0, an applied potential of 20 kV and a temperature of 20 degrees C. The analysis time is 10 min and the detection limits were between 0.88 and 1.71 microg mL(-1). Automatic clean-up and preconcentration is accomplished by using a C-18 minicolumn and 75% methanol as eluent. The limit of detection of NSAIDs can be up to 400-fold improved when using sample clean-up. The extraction efficiency for these compounds is between 71.1 and 109.7 microg mL(-1) (RSD 2.0-7.7%) for urine samples and from 77.2 to 107.1 microg mL(-1) (RSD 3.5-7.1%) for serum samples.

Automatic on-line coupling of supercritical fluid extraction and capillary electrophoresis

An interface for the automatic coupling of a supercritical fluid extractor (SFE) with capillary electrophoretic (CE) equipment, both commercially available, was developed with a view to improving sample treatment, which is a crucial step in capillary electrophoresis. Extracted analytes were collected in a trap following depressurization in the SFE and were transferred to the CE equipment across the interface. The key elements of the experimental assembly are a laboratory-made programmable arm and the autosampler of the CE equipment, both of which are controlled by a built-in microprocessor using an appropriate electronic interface and customized software. This combined system was successfully used to determine cresols and chlorophenols in liquid samples (river water and human urine) with increased precision, throughput, and automatability. The proposed arrangement opens up interesting prospects for the direct determination of analyte traces in solid samples without human intervention.

Use of supported liquid membranes incorporated in a flow system for the direct determination of eugenol in spice samples

A method for the determination of eugenol in spice samples based on the use of supported liquid membranes coupled to a flow system was developed. The solid sample is placed directly in the membrane unit without any treatment and the analyte is extracted from the sample, passes through the membrane and is conducted to the flow cell by the acceptor stream. This stream flows through the detector, allowing the measurement of the analyte by using a PVC-graphite composite electrode, versus Ag/AgCl/3 M KCl at +0.3 V, placed in a well-jet flow cell as amperometric detector. The method allowed the determination of eugenol in the range 0.5-30 micrograms ml-1 with a relative standard deviation of 5%. Results provided by the proposed procedure when applied to clove and seasoning samples agreed well with those obtained by a reference method.

Chronic diarrhea impairs intestinal antioxidant defense system in rats at weaning

The aim of the present study was to evaluate the influence of severe protein-energy malnutrition on the antioxidant defense system in the small and large intestine in rats at weaning. Chronic diarrhea and the subsequent malnutrition were induced by oral intake of a lactose-enriched diet. Twenty rats were weaned at 21 days of age, and the control group was fed a semipurified synthetic diet for two weeks. The malnourished group was fed the same diet but carbohydrates were replaced by lactose, and they developed diarrhea one day after. Rats were killed, and macroscopic and histological features were analyzed, DNA content was measured, and alkaline phosphatase, myeloperoxidase, and gamma-glutamyltranspeptidase activities were determined to assess the degree of intestinal injury. Glutathione levels as well as the activities of intestinal glutathione transferase, glutathione reductase, total glutathione peroxidase, selenium-dependent glutathione peroxidase, superoxide dismutase, and catalase were measured to study the antioxidant defense system. Malnourished rats showed loss of body weight and an increase in length and weight in jejunum and ileum, while no significant changes were observed in colon. Epithelial cells showed fewer and shorter microvilli, larger mitochondria with low inner density and loss of cristae, dilated endoplasmic reticulum, and Golgi apparatus. The protein-to-DNA ratio was higher in the jejunum, ileum, and colon of malnourished rats. Glutathione levels decreased 40% in jejunum and 50% in colon of malnourished rats. A 40-50% decrease in the activity of all the enzymes of the antioxidant defense system was observed in the jejunum and ileum of malnourished rats, while only catalase and glutathione transferase activities decreased 50% in colon. These results suggest that early chronic diarrhea and severe protein-energy malnutrition impair the antioxidant defense system in both the small and large intestine, which may have a role in the pathogenesis and maintenance of the vicious circle of malabsorption-diarrhea-malnutrition in infancy.

Experimental ulcerative colitis impairs antioxidant defense system in rat intestine

Increasing attention has been given recently to the role of free radicals in the pathogenesis of ulcerative colitis, since the inflamed intestine is exposed to oxidative stress generated by infiltrating macrophages and neutrophils within the lamina propia. The overall goal of this study was to evaluate whether experimental ulcerative colitis induces significant changes in the antioxidant defense system in an experimental model induced by the intrarectal administration of 2,4,6-trinitrobenzenesulfonic acid. Twenty rats were treated with 80 mg/kg body weight of trinitrobenzenesulfonic acid and 20 with the same volume of 0.9% NaCl. Rats were killed at one and two weeks after treatment to evaluate colon damage by light and electron transmission microscopy. The degree of tissue injury and inflammation was determined by measuring alkaline phosphatase, gamma-glutamyltranspeptidase, and myeloperoxidase activities and prostaglandin E2 and leukotriene B4. Glutathione levels and the activity of the enzymes of the antioxidant defense system were determined. Enzymatic markers of colon injury showed higher activities in rats with ulcerative colitis. Concentrations of prostaglandin E2 and leukotriene B4 were higher in the groups treated for one week with trinitrobenzenesulfonic acid and markers decreased after two weeks of treatment. All antioxidant enzyme activities were higher at one and two weeks after treatment; however, a significant decrease in total glutathione content was also observed. In conclusion, ulcerative colitis induced by trinitrobenzenesulfonic acid damages the intestinal mucosa and is accompanied by a shift in the antioxidant enzyme activities, and low levels of glutathione. This deficiency in glutathione could be a target for new therapies to treat ulcerative colitis.

Automatic microgravimetric determination of fats in milk products by use of supercritical fluid extraction with on-line piezoelectric detection

An on-line supercritical fluid extraction-piezoelectric detection system was developed and applied to the quantitative gravimetric determination of total fat in food samples (skimmed milk and cocoa). The proposed assembly provides all the advantages of an on-line system as regards automation, in addition to acceptable sensitivity and precision. Its strength lies in the design of the interface between the supercritical fluid extractor and the piezoelectric detector. Samples of skimmed milk and cocoa are weighed in the extraction thimble, previously loaded with I g of diatomaceous earth. A temperature of 100 degrees C and a CO2 fluid density of 0.60 mg/ml are used for extraction. The linear calibration range thus achieved is 0.005-0.07% w/w total fat, and the relative standard deviation is +/-2.3% (n=11; P=0.05). The throughput is six samples h(-1) (for the overall process). The proposed method was used to determine the total fat in food samples (milk, cocoa), the results being competitive with those of the Soxhlet methods for the same purpose.

Flow injection spectrophotometric determination of ascorbic acid in soft drinks and beer

Two spectrophotometric methods, a photochemical and a non-photochemical, for the determination of ascorbic acid in soft drinks and beer using a flow-injection system are proposed. The non-photochemical method is based on the redox reaction that takes place between ascorbic acid and Fe(III), yielding dehydroascorbic acid and Fe(II). Fe(II) reacts with 1,10-phenantroline, originating the reddish orange Fe(phen)3(2+) complex (ferroin). This complex is spectrophotometrically monitored at 512 nm, and the signal is directly related to the concentration of ascorbic acid in the sample. The photochemical method has the same basis, nevertheless, uses the irradiation with visible light to enhance the redox reaction and so achieve higher sensitivities in the analysis. The non-photochemical method shows a linear range between 5 and 80 microg mL(-1), with a relative standard deviation of 1.6% (n = 11), a detection limit of 2.7 microg mL(-1) and a sample throughput of 60 samples h(-1). The photochemical method shows a linear range between 1 and 80 microg mL(-1), with a relative standard deviation of 1.0% (n = 11 ), a detection limit of 0.5 microg mL(-1) and a sample throughput of 40 samples h(-1).

Automatic calibration in capillary electrophoresis

A direct, completely automated calibration procedure in capillary electrophoresis (CE) is presented. The manual calibration operations involved in analytical methods, such as external calibration, standard addition, and internal standard, were accomplished with a continuous flow system (CFS) coupled to commercial capillary electrophoresis equipment via a programmable arm. The system was managed by the proper CE microprocessor and allowed automatic calibration and direct quantification of the analytes in the sample without any manual pretreatment, therefore avoiding or minimizing manually associated errors. The whole system including peristaltic pumps and the programmable arm was connected via an electronic interface and completely controlled by a computer using a program written in GW-BASIC. The potential of this new CFS-CE arrangement was assessed by applying it to samples containing selected compounds.

Determination of pesticides in waters by automatic on-line solid-phase extraction-capillary electrophoresis

The separation of seven pesticides by micellar electrokinetic capillary chromatography in spiked water samples is described, allowing the analysis of pesticides mixtures down to a concentration of 50 microg l(-1) in less than 13 min. Calibration, pre-concentration, elution and injection into the sample vial was carried out automatically by a continuous flow system (CFS) coupled to a capillary electrophoresis system via a programmable arm. The whole system was electronically coupled by a micro-processor and completely controlled by a computer. A C18 solid-phase mini-column was used for the pre-concentration, allowing a 12-fold enrichment (as an average value) of the pesticides from fortified water samples. Under the optimal extraction conditions, recoveries between 90 and 114% for most of the pesticides were obtained.

Experimental colitis induced by trinitrobenzenesulfonic acid: an ultrastructural and histochemical study

Inflammatory bowel disease (IBD) of humans is a chronic and devastating disease of unknown etiology. Models of acute colitis in animals have been achieved by intrarectal administration of agents such as 2,4,6-trinitrobenzenesulfonic acid (TNBS) into rat colon. This agent induces focal inflammation and alterations in the colon with features similar to those found in chronic inflammatory diseases in humans. The aim of this study was to assess the effect of TNBS administration on histological and ultrastructural features of the rat colon, especially in areas not affected by transmural inflammation. Also in areas without transmural inflammation, we observed a significant increase in crypt diameter and in the number and area of the goblet cells, as well as alterations in the contents of mucin in goblet cells. We conclude that TNBS treatment in rats led to severe changes in normal architecture of the colon and also in damaged areas where no direct inflammation was produced.

Determination of chlorophenols in human urine based on the integration of on-line automated clean-up and preconcentration unit with micellar electrokinetic chromatography

A new method was developed and validated for the determination of chlorophenols in human urine by using micellar electrokinetic chromatography (MEKC) coupled via a mechanic arm to an on-line automatic clean-up and preconcentration unit for urine samples. Separation is accomplished by using a selective buffer consisting of 15 mM borate, 25 mM phosphate and 100 mM sodium dodecyl sulfate (SDS) at pH 9.1 in addition to a positive power supply of 25 kV at 18 degrees C. The proposed capillary electrophoresis (CE) method allows the separation of 11 chlorophenols within 7 min with a reproducibility as relative standard deviation (RSD) between 2.6% and 7.2%, and limits of detection (LODs) between 0.08 and 0.46 microg/mL for all chlorophenols. Urine samples were previously hydrolyzed with 37% HCl at 80 degrees C for 60 min and then cleaned on a C-18 mini-column. Recoveries ranged from 58% to 103%. The preconcentration treatment affords limits of determination between 4 and 12 ng/mL for all chlorophenols except pentachlorophenol and 4-chlorophenol, which could not be determined. The overall analysis time, including on-line clean-up, preconcentration and electrophoretic separation is 20 min per sample.

Enantiomeric separation of D- and L-carnitine by integrating on-line derivatization with capillary zone electrophoresis

A new capillary zone electrophoretic method has been developed for the enantiomeric separation and quantification of enantiomers of carnitine, D- and L-carnitine were derivatized with 9-fluorenylmethyl chloroformate in a flow system, working on-line with the capillary electrophoretic equipment. The separation was performed using a selective chiral buffer containing 2,6-dimethyl-beta-cyclodextrin (heptakis). Triethanolamine was used as electroosmotic modifier and the separation was carried out in a uncoated capillary. Under the optimal conditions the resolution between D- and L-carnitine was 1.2 and the limits of detection for both isomers were about 5.0 microM. The proposed method was applied to the determination of D-carnitine in excess of L-carnitine in synthetic samples, and the results demonstrated that the maximal D-:L-carnitine ratio determined was approximately 1:100.

Determination of anti-carcinogenic polyphenols present in green tea using capillary electrophoresis coupled to a flow injection system

A capillary electrophoresis (CE) method was developed for the simultaneous determination of a number of major ingredients of green tea. The components analysed were caffeine, adenine, theophylline, epigallocatechin-3 gallate, epigallocatechin, epicatechin-3 gallate, (-)-epicatechin, (+)-catechin, gallic acid, quercetin and caffeic acid. Separation was achieved using a fused capillary column with 0.15 M H3BO3 as buffer at a pH of 8.5, UV detection at 210 nm and 20 kV of voltage. Analysis was carried out after treatment (extraction, filtration and dilution) of the samples in a flow injection system which was coupled to a CE equipment via a programmable arm. The procedure allows the determination of these compounds in less than 20 min. Quantitative analysis was performed by the standard addition method. Limits of detection ranged between 0.04 microgram ml-1 for flavonols and 1.2 micrograms ml-1 for caffeine.

Dietary monounsaturated n-3 and n-6 long-chain polyunsaturated fatty acids affect cellular antioxidant defense system in rats with experimental ulcerative colitis induced by trinitrobenzene sulfonic acid

The intrarectal administration of trinitrobenzene sulfonic acid in rats induces ulcerative colitis, which results in histological alterations of colonic mucosa, severe modification of the cellular antioxidant defense system, and enhanced production of inflammatory eicosanoids. This study evaluated the influence of different dietary fatty acids, i.e., monounsaturated, n-3, and n-3 + n-6 polyunsaturated fatty acids, on the recovery of the colonic mucosa histological pattern, the cellular antioxidant defense system of colon, and PGE2 and LTB4 colonic mucosa contents in a model of ulcerative colitis induced by intrarectal administration of trinitrobenzene sulfonic acid. Administration of dietary n-3 polyunsaturated fatty acids led to a minimum stenosis score, a higher histological recovery, lower colon alkaline phosphatase and gamma-glutamyltranspeptidase activities, and lower mucosal levels of PGE2 and LTB4 compared with the other two experimental groups. However, glutathione transferase, glutathione reductase, glutathione peroxidase, and catalase activities were lower in the group treated with n-3 polyunsaturated fatty acids than in the groups fed with either the monounsaturated or the n-6 + n-3 polyunsaturated enriched diet. We conclude that n-3 polyunsaturated fatty acids can be administered to prevent inflammation in ulcerative colitis, but they cause a decrease in the colonic antioxidant defense system, promoting oxidative injury at the site of inflammation.

Sensitive determination of paraquat and diquat at the sub-ng ml-1 level by continuous amperometric flow methods

Two methodologies are described for the determination of paraquat and diquat. The first is based on the pre-treatment of an electrode with a surfactant solution, which improves the electrochemical determination of the herbicides. Linear calibration graphs were obtained in the ranges 10-80 and 10-100 ng ml-1 for paraquat and diquat, respectively. The limits of detection were 6.32 for paraquat and 4.80 ng ml-1 for diquat. The method was applied to the determination of the herbicides in synthetic water samples. The second methodology is based on the preconcentration of paraquat and diquat in a minicolumn packed with a cation-exchange material. The determination ranges and detection limits depend on the sample volume used (5-50 ml). Thus, 50 ml of sample provides limits of detection of 0.016 and 0.020 ng ml-1 for paraquat and diquat, respectively. The applicability of the method was demonstrated with the determination of the herbicides in both synthetic and real water samples.

IL-4 improves the detection of cytogenetic abnormalities in multiple myeloma and increases the proportion of clonally abnormal metaphases

In the present study the incidence of abnormal karyotypes and the number and proportion of abnormal metaphases obtained in multiple myeloma (MM) using three culture conditions were compared: unstimulated culture (72 h), IL-6/GM-CSF-stimulated culture (120 h) and IL-4-stimulated culture (120 h). The three types of culture conditions were assessed simultaneously on bone marrow samples from 30 consecutive myeloma patients. In addition DNA content (DNA ploidy and cell cycle) was analysed by flow cytometry. The number of MM samples with clonal karyotypic abnormalities was higher after IL-4-stimulated cultures (53%) than it was after IL-6 + GM-CSF (37%) and unstimulated (30%) cultures. The benefit of IL-4 was also observed in cases with low numbers of plasma cells in the bone marrow, in early clinical stages and in untreated patients. In those cases in whom clonal chromosomal abnormalities were detected by the three culture methods. the cytogenetic findings were always identical. According to our results the addition of IL-4 to the cultures of bone marrow cells in MM increases the number of abnormal metaphases.

Direct determination of biogenic amines in wine by integrating continuous flow clean-up and capillary electrophoresis with indirect UV detection

A flow-injection manifold for automating the determination of biogenic amines in wine using capillary electrophoresis (CE) with indirect UV detection was developed. The ensuing method involves clean-up and solid-phase extraction (SPE) of the target analytes in the sample. Various treatments involving different SPE minicolumns were tested and compared. The C18 minicolumn was chosen to concentrate the amines following addition of ammonium chloride and ammonium hydroxide as buffer to neutralize them. Additions of amine standards were used to determine recoveries. Biogenic amines can be separated and detected after SPE with limits of detection in the range 0.05-0.1 microgram ml-1 by using 4 mM copper(II) sulphate, formic acid and 18-crown-6 as running buffer. All the amines studied are eluted within 15 min under the optimum conditions established. The overall process was successfully used to identify biogenic amines in various types of wine from different Spanish regions.

Dietary nucleotides correct plasma and liver microsomal fatty acid alterations in rats with liver cirrhosis induced by oral intake of thioacetamide

BACKGROUND/AIMS

Dietary nucleotides modulate a number of metabolic processes, including long-chain polyunsaturated fatty acid metabolism. In this study, we evaluated the effect of dietary nucleotides on plasma and liver microsomal fatty acid profiles in a rat model of liver cirrhosis induced by oral intake of thioacetamide.

METHODS

Fifty-four female Wistar rats were assigned to one of the following groups: rats in the thioacetamide group (n=45) were given 300 mg thioacetamide/l in their drinking water for 4 months, and rats in the control group (n=9) received water during the same period. After 4 months of treatment, 9 rats in each group were killed. The remaining rats in the thioacetamide group were divided into two new groups, and the animals in each were allowed to recover for 1 or 2 weeks on either a nucleotide-free diet or the same diet supplemented with 50 mg of each of the following: AMP, GMP, CMP, IMP and UMP per 100 g diet.

RESULTS

Saturated (mainly stearic acid), monounsaturated, and n-6 long-chain polyunsaturated fatty acids (mainly arachidonic acid), and also the unsaturation index decreased in plasma of rats with experimental cirrhosis. Administration of the diet supplemented with nucleotides to thioacetamide-treated rats corrected plasma levels of saturated, n-6 long-chain polyunsaturated fatty acids and the unsaturation index. In liver microsomes, the cirrhotic rats showed lower levels of protein and higher levels of palmitic, oleic, linoleic and arachidonic acids. Protein concentrations and levels of all the above-mentioned fatty acids were corrected with the nucleotide-enriched diet.

CONCLUSIONS

Dietary nucleotides contribute to correcting plasma and liver microsomal fatty acid alterations in rats with liver cirrhosis induced by chronic oral administration of thioacetamide.