An infarcted wandering spleen leading to a sigmoid volvulus presenting with acute large bowel obstruction: a case report.

A wandering spleen is a very rare event characterised by the absence of the spleen in its anatomical position due to the hyperlaxity of its ligaments. We present a case of wandering spleen complicated by splenic vascular pedicle torsion, thrombosis and subsequent splenic infarction. Compression of the infarcted spleen on the rectosigmoid junction led to the development of a sigmoid volvulus, which presented as an acute large bowel obstruction. The patient underwent emergency laparotomy, splenectomy, sigmoid decompression and sigmoidopexy. After a follow-up period of two years, the volvulus had not recurred.

Reproducibility of LI-RADS treatment response algorithm for hepatocellular carcinoma after locoregional therapy.

PURPOSE: To determine inter-reader agreement in categorizing hepatocellular carcinoma (HCC) treated with locoregional therapy using the Liver Imaging Reporting and Data System (LI-RADS) treatment response (LR-TR) algorithm. MATERIALS AND METHODS: A total of 93 patients with a total of 112 HCC nodules that were treated using thermal ablation or transarterial chemoembolization were prospectively included. There were 79 men and 14 women with a mean age of 55±2.6 (SD)years (range: 48-63years). All patients underwent magnetic resonance imaging (MRI) examination of the liver and MR images were analyzed by two independent observers. Treated HCC nodules were categorized into four groups according to LR-TR scoring system including: (i) LR-TR non-evaluable (treated, response not evaluable); (ii) LR-TR nonviable (treated, probably or definitively not viable); (iii) LR-TR equivocal (treated, equivocally viable) and (iv) LR-TR viable (treated, probably or definitively viable). The inter-observer agreement in LR-TR categorization was assessed using the kappa statistics. RESULTS: There was excellent inter-observer agreement between the two reviewers for overall treated HCC according to LR-TR algorithm (kappa=0.938; 95% CI: 0.89-1.00; P=0.001) with 97.31% agreement. The LR-TR categories by both reviewers were non-viable (77/112; 69.6% and 76/112; 67.9%), viable (30/112; 26.8% and 32/112; 27.7%) and equivocal (5/112; 4.4% and 4/112; 3.6%). There was excellent inter-observer agreement for LR-TR nonviable (kappa=0.938; 95% CI: 0.87-1.0; P=0.001) with 97.3% agreement, LR-TR viable (kappa=0.955; 95% CI: 0.89-1.00; P=0.001) with 98.2% agreement and good inter-observer agreement for LR-TR equivocal (kappa=0.700; 95% CI: 0.28-1.0; P=0.001) with 97.3% agreement. CONCLUSION: LR-TR algorithm conveys high degrees of inter-observer agreement for the evaluation of treatment response of HCC after thermal ablation and transarterial chemoembolization.

Papillary thyroid carcinoma in cervical lymph nodes with vanished thyroid gland after ablation of Graves' disease by radioactive iodine.

Primary thyroid carcinoma after thyroid ablation by radioactive iodine is rare. We present a very rare condition of lateral apparent papillary thyroid carcinoma eight years after receiving radioactive iodine for thyrotoxicosis, which led to complete anatomical and functional involution of the thyroid gland.

Use of charge-transfer complexation in the spectrophotometric analysis of certain cephalosporins.

Three simple, rapid and sensitive spectrophotometric procedures were developed for the analysis of cephapirin sodium (1), cefazoline sodium (2), cephalexin monohydrate (3), cefadroxil monohydrate (4), cefotaxime sodium (5), cefoperazone sodium (6) and ceftazidime pentahydrate (7) in pure form as well as in their pharmaceutical formulations. The methods are based on the reaction of these drugs as n-electron donors with the sigma-acceptor iodine, and the pi-acceptors: 2,3-dichloro-5,6-dicyano-p-benzo-quinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Depending on the solvent polarity, different coloured charge-transfer complexes and radicals were developed. Different variables and parameters affecting the reactions were studied and optimized. The obtained charge-transfer complexes were measured at 364 nm for iodine (in 1,2-dichloroethane), 460 nm for DDQ (in methanol) and 843 nm for TCNQ (in acetonitrile). Ultraviolet-visible, infrared and (1)H-nuclear magnetic resonance techniques were used to study the formed complexes. Due to the rapid development of colours at ambient temperature, the obtained results were used on thin-layer chromatograms for the detection of the investigated drugs. Beer's plots were obeyed in a general concentration range of 6-50, 40-300 and 4-24 mug ml(-1) with iodine, DDQ and TCNQ, respectively, with correlation coefficients not less than 0.9989. The proposed procedures could be applied successfully to the determination of the investigated drugs in vials, capsules, tablets and suspensions with good recovery; percent ranged from 96.47 (+/-1.14) to 98.72 (+/-1.02) in the iodine method, 96.35 (+/-1.62) to 98.51 (+/-1.30) in the DDQ method, and 95.98 (+/-0.78) to 98.40 (+/-0.87) in the TCNQ method. The association constants and standard free energy changes using Benesi-Hildebrand plots were studied. The binding of cephalosporins to proteins in relation to their molar absorptivities was studied.

Charge-transfer complexes of barbiturates and phenytoin.

Simple and sensitive spectrophotometric methods are described, for the first time, for the determination of sodium salts of phenobarbital (1), thiopental (2), methohexital (3) and phenytoin (4). The methods are based on the reaction of these drugs as n-electron donors with the sigma-acceptor iodine and various pi-acceptors: 7,7,8,8-tetracyanoquinodimethane; 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; 2,3,5,6-tetrachloro-1,4-benzoquinone; 2,3,5,6-tetrafluoro-1,4-benzoquinone; 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone; tetracyanoethylene and 2,4,7-trinitro-9-fluorenon. Depending on the solvent polarity, different coloured charge-transfer complexes and radicals were developed. Different variables and parameters affecting the reactions were studied and optimized. The formed complexes were examined by UV/VIS, infrared and (1)H-NMR. Due to the rapid development of colours at ambient temperature, the obtained results were used on thin layer chromatograms for the detection of the investigated compounds. Beer's plots were obeyed in a general concentration range of 1-400 mug ml(-1) for the investigated compounds with different acceptors. Interference from some co-formulated drugs was also studied. No interference was observed due to additives commonly present in the pharmaceutical preparations. The proposed methods could be applied successfully to the determination of the investigated compounds in pure and pharmaceutical dosage forms with good accuracy and precision, the recoveries ranged from 98.7+/-0.5 to 101.1+/-0.5%. The results were compared favourably with the official methods.

Determination of barnidipine in human serum and dog plasma by HPLC with electrochemical detection.

Barnidipine is a 1,4-dihydropyridine calcium antagonist. HPLC was conducted on a polybutadiene coated alumina column using an alkaline mobile phase and an electrochemical detector to determine the content of this drug in serum and plasma. A good linear relationship between barnidipine concentration and peak height was found in 5-500 ng/ml with a correlation coefficient of 0.998. The detection limit was 1 ng/ml. The within-day and day-to-day variations were examined for control human serum. Relative standard deviation of within-day assay for serum spiked with 10 ng/ml barnidipine.HCl was 6.9% and the recovery was 104%. A pharmacokinetic study was made in which the time course of barnidipine in dog plasma was followed.

Selective spectrophotometric determination of ascorbic acid in drugs and foods.

A new analytical method was developed for the determination of ascorbic acid. The method is based on the reaction of ascorbic acid with 4-chloro-7-nitrobenzofurazane (NBD-Cl) in the presence of 0.2M sodium hydroxide, where a bluish green colour (lambda(max) 582 nm) is developed after dilution with 50% (v/v) aqueous acetone solution. Beer's law was obeyed in a concentration range of 5-20 microg ascorbic acid/ml with a good correlation coefficient (r = 0.9990). The method was found to be highly specific for the determination of ascorbic acid in the presence of dehydro-ascorbic acid, all other vitamins and minerals possibly present in multivitamin preparations, rutin, salicylamide, acetyl salicylic acid, paracetamol, caffeine, phenylephrine hydrochloride and dipyrone. Moreover, the proposed procedure was also successfully applied for the determination of ascorbic acid in some canned and fresh fruit juices, some vegetables and infant milk products without interference from coloured and other substances present in the plant extracts.

A selective spectrophotometric method for determination of quercetin in the presence of other flavonoids.

A simple, rapid and highly selective method for determination of quercetin in the presence of other flavonoids was developed. The method is based on the oxidation reaction of quercetin in neutral aqueous solution with N-bromosuccinimide (NBS) in the presence of phenol to give a violet chromogen measurable at 510 nm. Beer's law was valid within a concentration range of 2.5-30 mug/ml with a good correlation coefficient (r = 0.9990). All variables were studied to optimize the reaction conditions. The method is highly selective for quercetin. Other investigated flavonoids do not interfere. Mixtures of flavonoids were also analysed through native UV measurements of absorbance readings at 370 nm and then at 510 mn after adopting the proposed procedure. The method could also be utilized for the quantitative determination of quercetin in some plant extracts. Moreover, the proposed procedure could be considered as a good tool to follow the hydrolysis of quercetin glycosides.

Spectrophotometric determination of tetracycline and oxytetracycline in pharmaceutical preparations.

A simple, rapid and sensitive spectrophotometric procedure for the assay of tetracycline hydrochloride and oxytetracycline hydrochloride has been developed. 2,2-Diphenyl-l-picrylhydrazyl (DPH), an intensely violet-coloured stable free radical, is changed in colour on reaction with the antibiotics investigated. The decrease in the intensity of the violet colour is used to measure the concentration of the drug. All measurements are made at 520 nm on methanolic solutions of the drug and reagent, buffered at pH 6. Beer's law is obeyed in the concentration ranges 2.5-15 and 2.5-20 mug/ml for tetracycline and oxytetracycline respectively. The proposed method has been successfully applied to analysis of the bulk drugs and their pharmaceutical formulations.

Utility of certain pi-acceptors for the spectrophotometric determination of some penicillins.

Two simple and sensitive spectrophotometric methods are described for the determination of six penicillin derivatives. The methods are based on the reaction of these drugs as n-electron donors with either 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) as pi-acceptors, to give a highly coloured radical anion. The coloured products are quantified spectrophotometrically at 460 and 842 nm for DDQ and TCNQ, respectively. The optimization of the different experimental conditions is described. The interference from streptomycin sulphate and common degradation products was also studied. The proposed methods were applied successfully to the determination of the different penicillins investigated, either in pure or dosage forms, with good accuracy and precision. The results were compared with those given by the official United States Pharmacopeial XXI method.

Spectrophotometric methods for the determination of sulphathiourea.

Three simple and sensitive spectrophotometric methods are described for the determination of sulphathiourea. The methods are based on the interaction of this thioamide with either iodine, tetracyanoethylene (TCNE) or copper nitrate to give the corresponding charge-transfer or metal-ion complexes, which can be measured at 363, 350 and 353 nm, respectively. In each case, a 1:1 complex was formed. Beer's law is obeyed for each procedure in a concentration range of 1-150 micrograms ml-1. The proposed procedures can be applied to the determination of sulphathiourea in its pharmaceutical formulations.

Spectrophotometric determination of some pharmaceutical amides through charge-transfer complexation reactions.

A spectrophotometric method is described for the assay of fenpipramide hydrochloride, isopropamide iodide, trimethobenzamide hydrochloride, morphazinamide hydrochloride and tolazamide. The method is based on the formation of a charge-transfer complex between the drug as n-donor and iodine, a sigma-acceptor. The product exhibits absorption maxima at 295 and 365 nm; measurements are made at 365 nm for fenpipramide and at 295 nm for the other compounds. Beer's law is obeyed in a concentration range of 1-120 micrograms ml-1. The method is rapid, simple and sensitive and can be applied to the analysis of some commercial and laboratory prepared tablets without interference. A more detailed investigation of the complex was made with respect to its composition, association constant and free energy change.

Use of p-benzoquinone for the spectrophotometric determination of certain sulphonamides.

A simple spectrophotometric method for the determination of 15 sulphonamides in bulk and in dosage forms is described. The method is based on the interaction of p-benzoquinone with sulphonamides in 0.1 M hydrochloric acid. The resulting chromophore is measured at 500 nm. The effects of different variables on colour development were established. Beer's law was obeyed in a concentration range of 10-50 micrograms ml-1. Results from the analysis of different sulphonamide tablets and ophthalmic solutions marketed locally were in good agreement with that of a reference method. Correlations between A1cm(1%) and certain physical parameters such as pKa values, characteristic volume Vx, and molecular connectivity indices 1X and 1Xv were determined by linear regression equations. A poor correlation was found between A1cm(1%) and bulkiness parameters but a highly significant negative correlation was obtained with apparent pKa values.