LC of pharmaceutically important halogenated 8-hydroxyquinolines after precolumn derivatization with Pd (II)

An accurate, sensitive, and selective reversed phase high performance liquid chromatographic (HPLC) method was developed for the analysis of two halogenated 8-hydroxyquinoline derivatives; clioquinol (CQN) and iodoquinol (IQN). The proposed method depends on the complexation ability of the studied compounds with Pd(II) ions. Reversed phase chromatography was conducted using a 300 x 3.9 mm i.d. stainless steel column packed with 10 microm Bondclone phenyl at ambient temperature. A solution containing 0.005% w/v of Pd(II)-chloride in a mixture of acetonitrile-methanol-water (3:3:4 v/v/v) of pH 3.7 as a mobile phase pumped at a flow rate of 0.75 ml min(-1). UV-detection was performed at 282 and 285 nm for CQN and IQN, respectively. The method showed excellent linearity in the range 0.05-1.8 and 0.1-3.0 microg ml(-1) with limit of detection (S/N=2) 4.8 ng ml(-1) (1.57 x 10(-8) M) and 6.4 ng ml(-1) (1.61 x 10(-8) M) for CQN and IQN, respectively. The suggested method was successfully applied for the analysis of the studied drugs in bulk with average% recoveries of 99.68+/-0.44 for CQN and 99.65+/-0.53 for IQN. The proposed method was successfully applied for the analysis of the studied drugs in single or combined dosage forms with average% recoveries of 99.41+/-0.51-100.02+/-0.63. The proposed method could be used successfully for the determination of the studied compounds in the presence of their degradation product as they could be eluted with different retention times. The presence of metronidazole (MNZ) or tolnaftate (TFT) with the studied drugs does not affect their accurate determination. The results obtained were favorably compared with those obtained by the reference method. The results were satisfactorily, accurate, and precise.

Voltammetric determination of praziquantel in tablets and biological fluids

A simple method is described for the determination of praziquantel (CAS 55268-74-1) in its pure form, tablet formulations and biological fluids. The proposed method depends upon the polarographic activity of praziquantel at the dropping mercury electrode (DME) in Britton Robinson buffers, whereby a well-defined catholic wave is produced over the pH range 7-12. The wave was characterized as being irreversible diffusion-controlled with limited adsorption properties. The diffusion current constant (Id) was 0.56 +/- 0.004 (n = 11). The current-concentration relationship was found to be rectilinear over the range 8-48, 3.2-38.4 and 0.48-20 micrograms.ml-1 using direct current (DCt), differential pulse polarographic (DPP) and alternating current (ACt) odes, respectively, with minimum detection limit (S/N = 2) of 0.32 microgram.ml-1 (1.02 x 10(-6) mol/l and 0.02 microgram.ml-1 (6.4 x 10(-8) mol/l) for DPP and ACt modes respectively. The average percent recovery was favourably compared to a reference method with a satisfactory standard deviation. The proposed method was applied to spiked human urine and plasma. The percentage recoveries were 99.33 +/- 0.79 and 98.23 +/- 0.53, respectively.

Derivative spectrophotometric analysis of 4-quinolone antibacterials in formulations and spiked biological fluids by their Cu(II) complexes

A derivative UV-spectrophotometric analytical procedure was developed for determination of three 4-quinolone antibacterials: norfloxacin (NFX), ciprofloxacin (CFX), and sparfloxacin (SFX). The method depends on the complexation of Cu(II) with the studied compounds in aqueous medium. A third order, measurement was applied for their quantification. A linear correlation was established between the amplitude of the peak and concentration for all the studied drugs in the range of 15-80, 35-120, and 200-700 ng/mL, with minimum detectability (S/N = 2) of 1.0, 1.3, and 5.1 ng/mL for NFX, CFX, and SFX, respectively. The method was successfully applied for accurate, sensitive, and selective determination of the studied drugs in bulk and tablets formulation with average percentage recoveries of 99.22 +/- 0.55 to 100.33 +/- 1.60. The results obtained were favorably compared with those of the reference method. The method was also used to determine sparfloxacin in spiked human plasma and urine. The results obtained were satisfactory, accurate, and precise.

Use of cytokeratins 7 and 20 in determining the origin of metastatic carcinoma of unknown primary, with special emphasis on lung cancer

Metastatic carcinoma of unknown primary is a common problem, accounting for up to 10-15% of all solid tumours at presentation. Proper identification of the site of origin has prognostic and therapeutic significance. Prior immunohistochemical methods to identify the site of origin have been useful in a limited number of cases. Differential cytokeratin staining may be useful in this setting, particularly in identifying metastases from lung cancer. We have identified 144 cases of metastatic carcinoma of unknown primary to bone, lung or liver at Brigham and Women's Hospital between 1 January 1997 and 1 July 1998. Cytokeratin (CK) 7 and CK20 were used in 75 of these cases to narrow down the possible sites of the primary tumours. All of these cases were ambiguous as to the site of the primary tumour. Forty-five cases were CK7+/CK20-, 15 cases were CK7-/CK20-, 9 cases were CK7-/CK20+ and 6 cases were CK7+/CK20+. Three of the cases were selected for detailed presentation and discussion as well as a discussion of the pertinent literature. Overall, the CK7+/CK20- phenotype favours a lung primary, the CK7+/CK20+ phenotype strongly favours transitional cells (urothelial) carcinoma, the CK7-/CK20+ phenotype favours colorectal carcinoma, while the CK7-/CK20- profile is not helpful.

Voltammetric analysis of certain 4-quinolones in pharmaceuticals and biological fluids

The voltammetric behaviour of Enrofloxacin (I), Sparfloxacin (II) and Fleroxacin (III) was studied using direct current (DCt), differential pulse (DPP) and alternating current (ACt). All the drugs manifest cathodic waves in Britton Robinson buffer over the pH range of 4.0-11.98. The waves were characterized as being irreversible, diffusion-controlled with limited adsorption properties. The diffusion current concentration relationships were found to be rectilinear over the ranges 4 x 10(-5) x 10(-4) M, 1 x 10(-5)-2 x 10(-4) M, 1 x 10(-5)-4 x 10(-4) M using DCt mode for I, II and III, respectively and 1 x 10(-6)-4 x 10(-5) M, 1 x 10(-6)-1 x 10(-4) M, and 2 x 10(-6)-8 x 10(-5) M, using DPP mode for I, II and III respectively, with minimum detectability (S/N = 3) of 1 x 10(-7) M for I, II and 2 x 10(-7) M for III. The proposed method was successfully applied to the determination of the studied compounds either per se or in formulations and biological fluids. The results obtained were concordant to those given using reference methods.

A simple kinetic spectrophotometric method for the determination of oxamniquine in formulations and spiked biological fluids

A simple and sensitive kinetic method for the determination of oxamniquine in pharmaceutical preparations and biological fluids was developed. The procedure is based upon a kinetic investigation of the oxidation reaction of the drug with alkaline potassium permanganate at room temperature for a fixed time of 20 min. The absorbance of the colored manganate ions was measured at 610 nm. Alternatively, the decrease in the absorbance of potassium permanganate after addition of the drug was measured at 525 nm. The absorbance concentration plots in both procedures were rectilinear over the range 0.5-4 microg ml(-1). The concentration of oxamniquine is calculated using the corresponding calibration equation for the fixed-time method. The determination of oxamniquine by fixed-concentration and rate-constant methods was feasible with the calibration equations obtained but the fixed time method had been found to be more applicable. Both procedures were applied to the determination of oxamniquine in formulations. The results obtained were in good agreement with those obtained using the official method. The fixed time method of 20 min was further applied to spiked human urine and plasma, the recoveries (%) were 100.94 +/- 0.57 and 98.07 +/- 0.88 for urine and plasma, respectively, at 610 nm, and 97.51 +/- 1.27 and 95.69 +/- 1.23 for urine and plasma, respectively, at 525 nm.

A Simple Kinetic Spectrophotometric Method For The Determination of Certain 4-Quinolones in Drug Formulations

An accurate simple and selective kinetic procedure for the determination of certain 4-quinolones namely, norfloxacin (I), ofloxacin (II), enrofloxacin (III), fleroxacin (IV), ciprofloxacin (V) and pefloxacin (VI) is described. The procedure is based on reacting the studied compounds in acidic media (0.1 M HCL) with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) in presence of cerium (IV) ammonium sulphate as an oxidant at room temperature for a fixed time of 20 min. for (I), (III), 12 min for (II) and 30 min for IV , V and VI, then the absorbance of the reaction product is measured at 630 nm. The concentration of the studied compounds is computed using the corresponding calibration curve equation for the fixed-time method. The absorbance-concentrations plot is rectilinear over the range 20-100 ug.ml-1 for (I), 2 - 20 ug.ml-1 for (II), 10 - 74 ug.ml-1 for (III), 10 - 60 ug.ml-1 for IV, 10 - 50 ug.ml-1 for IV and 8 - 40 ug.ml-1 for VI. The determination of the studied compounds by the fixed-concentration and rate constant methods is feasible with the calibration equation obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets and ampoules and the results obtained were compared statistically with the reference methods.

Spectrofluorimetric analysis of certain 4-quinolone in pharmaceuticals and biological fluids

A highly sensitive spectrofluorimetric procedure is developed for the analysis of certain 4-quinolone antibiotics: sparfloxacin (I), oxolonic acid (II), flumequine (III) and enrofloxacin (IV) in their pharmaceutical dosage forms or in biological fluids. This procedure is based upon the intrinsic fluorescence in acetonitrile for sparfloxacin or upon the highly enhanced fluorescence obtained by the interaction of the drugs with AlCl3. The optimum pH for the maximum fluorescence intensity is 8-8.5 for I, 5-6 for II, III and pH 3.5 for IV. The different experimental parameters that affect the fluorescence intensity were carefully studied and incorporated into the procedure.

Fluorimetric determination of oxamniquine in biological fluids

A highly sensitive and specific fluorimetric method was developed for the determination of oxamniquine in biological fluids (urine and plasma). The proposed method is based on the reduction of oxamniquine using zinc/calcium chloride to obtain its nitroso derivative. The latter is then allowed to react with 2-cyanoacetamide to get a highly fluorescent product. The different experimental parameters affecting the intensity of the fluorescence were carefully studied and incorporated into the procedure. Under the described conditions, the method is applicable over the concentration range of 0.08-0.88 microgram/ml with a minimum detectability (S/N = 2) of 8 ng/ml. The percentage recoveries from spiked urine and plasma were 99.75 +/- 1.58 and 97.46 +/- 0.44%, respectively.

Cancer-associated retinopathy in a patient with non-small-cell lung carcinoma

Cancer-associated retinopathy (CAR) is a paraneoplastic syndrome most often associated with small-cell lung carcinoma (SCLC), and it has been reported in patients with other malignancies. Antibodies against recoverin, a 23-kDa protein, have been found in patients with CAR suggesting an autoimmune phenomenon. Herein is the first report of a patient with non-small-cell lung cancer (NSCLC) in whom anti-recoverin antibodies were detected in the serum. Steroid therapy, chemotherapy, and radiation therapy did not help the patient's vision. Progressive loss of vision in patients with lung cancer should, potentially, be tested for CAR.

p53 Induces myocyte apoptosis via the activation of the renin-angiotensin system

The mechanism by which p53 activates apoptosis in various cell systems is unknown. In the absence of an external death stimulus, p53 and p53-dependent genes, bcl-2 and bax, cannot trigger apoptosis. However, p53 may enhance not only transcription of bax and repress bcl-2, but also may upregulate the local renin-angiotensin system, inducing the formation and secretion of angiotensin II from the cells. To test this hypothesis, adult rat ventricular myocytes were infected with AdCMV.p53, which resulted in downregulation of Bcl-2, upregulation of Bax, and death of 34% of the cells. Gel retardation assays demonstrated p53 binding in the promoters of angiotensinogen and angiotensin II AT1 receptor subtype. Angiotensinogen and AT1 mRNAs increased in AdCMV.p53 cells and this phenomenon was associated with a 14-fold increase in the secretion of angiotensin II. The AT1 receptor blocker losartan and angiotensin II antibody prevented p53-induced apoptosis. Thus, p53 enhances the myocyte renin-angiotensin-system and decreases the Bcl-2/Bax ratio in the cells, triggering apoptosis. The identification of this new pathway in p53-mediated apoptosis may be critical in the alterations of myocardial function in the pathologic heart.

CD27, a member of the tumor necrosis factor receptor family, induces apoptosis and binds to Siva, a proapoptotic protein

Members of the tumor necrosis factor receptor (TNFR) superfamily are important for cell growth and survival. In addition to providing costimulatory signals for cell proliferation, ligation of both TNFR1 and Fas can result in programmed cell death or apoptosis. The underlying mechanism requires an intact 80-aa stretch present in the cytoplasmic tails of both TNFR1 and Fas, termed the death domain (DD). Here we show that CD27, a member of the TNFR family, expressed on discrete subpopulations of T and B cells and known to provide costimulatory signals for T and B cell proliferation and B cell Ig production, can also induce apoptosis. Co-crosslinking of surface Ig receptors along with ligation of CD27 augments CD27-mediated apoptosis. Unlike TNFR1 and Fas, the cytoplasmic tail of CD27 is relatively short and lacks the DD. Using the yeast two-hybrid system, we have cloned a novel protein (Siva) that binds to the CD27 cytoplasmic tail. It has a DD homology region, a box-B-like ring finger, and a zinc finger-like domain. Overexpression of Siva in various cell lines induces apoptosis, suggesting an important role for Siva in the CD27-transduced apoptotic pathway.

Europium(III) ion probe spectrofluorometric determination of diclofenac sodium

A new method has been devised for the determination of diclofenac sodium in bulk and in pharmaceutical preparations using Eu3+ ions as the Fluorescent probe. The technique was built around the hypersensitive property of the transitions of the fluorescent probe ion, Eu3+, at 616 nm. This is normally a forbidden transition, but the interaction with diclofenac sodium, which contains a carboxylic group, makes the transition allowed and enhances the intensity of its fluorescence emission. The Eu3+ fluorescence emission at 592 nm comes from a non-hypersensitive transition and is not affected by ligation. The intensity ratio, R, defined as I592/I616, was used as a measure of the percentage of bound probe ions. Diclofenac and Eu(III) forms a (1:1) molar complex. The relative stability constant of the complex was found to be 10(5). A linear relationship between bound Eu3+ and the concentration of diclofenac sodium was found for concentrations from 10 to 200 micrograms ml-1, with a recovery percentage of 100.22 +/- 2.27. The method shows a good agreement with a spectrophotometric method.

Salicylamide reverses the aspirin-antagonistic effect of salicylic acid on rat platelet cyclooxygenase

The antagonistic effect of salicylic acid (SA), the major metabolite of aspirin, on aspirin (ASA)-induced inhibition of cyclooxygenase has been recognized in vivo and in vitro. Salicylamide is available with aspirin in some analgesic preparations. Salicylamide shares important characteristics with salicylic acid including the lack of effect on cyclooxygenase and platelet aggregation as well as a close structural resemblance. This prompted us to study the interaction of salicylamide with aspirin and/or SA on rat platelet and cyclooxygenase. Our results showed that salicylamide has, unlike SA, no blocking effect on the anticyclooxygenase effect of aspirin in vitro. Moreover, salicylamide could dose-dependently prevent the aspirin-blocking effect of SA on platelet cyclooxygenase. These results suggest that salicylamide and SA compete for a receptor on cyclooxygenase different to that of aspirin. A functional model of cyclooxygenase enzyme is proposed.

Assay of certain oral contraceptive formulations by gas chromatography-mass spectrometry-selected ion monitoring

The combined technique of gas chromatography--mass spectrometry--selected ion monitoring (GC-MS-SIM) has been employed for the nanogram level determination of ethinyloestradiol, mestranol, norgestrel and norethisterone in various oral contraceptive formulations. Steroids were assayed as their DMES-or methoxime DMES ether derivatives in the presence of ethisterone as the internal standard. The method is accurate, specific and suitable for single tablet assay.

Studies on carbohydrates extracted from native and chemically treated Biomphalaria alexandrina snails

1. Carbohydrates were extracted from total tissue extracts of Biomphalaria alexandrina snails and were analyzed to their monosaccharides using GLC. 2. The snails were chemically treated with thioxanthone derivatives (compounds I, II, III) and the change in the monosaccharide constituents of their carbohydrates was investigated. 3. The isolated monosaccharides from native and chemically pretreated snails were injected into mice and their protective effects were examined after infection of mice with cercariae of Schistosoma mansoni. 4. The results showed that the main monosaccharides in carbohydrates of snails were galactose, glucose, fucose and mannose and that chemical treatment caused a drop in the galactose content. 5. Moreover, monosaccharide fractions from snails treated with compound III were the most effective in inducing protection against Schistosoma infection in mice.

Sensitive colorimetric determination of copper (II) ions in some chemicals and multivitamins

A sensitive and selective colorimetric method has been devised for the micro-determination of copper (II) ions in pure form, some chemicals and multivitamin preparations. The method depends on the formation of stable blue complexes in ammonia medium peaking at 615 nm between copper (II) ions, oxalyldihydrazide and one of the following aldehydes: 4-nitrobenzaldehyde, 2-nitrocinnamaldehyde and formaldehyde with minimum detection limits 0.1, 0.16 and 1.1 ppm, respectively. Several metal ions do not interfere. The optimum reaction conditions were studied and the results obtained were favorably comparable to the diethyldithiocarbamate method.

Electron microscopic and chemical study of the deposits formed on the copper and inert IUCDs

The surface of 25 copper IUCDs and 25 inert IUCDs that had been in utero for less than 6 months or more than a year was examined by the scanning electron microscope and the deposits were extracted from another 100 copper and inert IUCDs that had been in utero for less than 6 months or more than a year and examined by the atomic analyser. The most apparent changes were, respectively, amorphous deposits and cellular debris, crystalline deposits, cracks, duplex coating, distortion and corrosion. Duplex coating was found only on inert IUCDs, but corrosion was found on copper IUCDs. The duration of use of the IUCDs had marked effect on the type of the deposits. Bleeding with IUCDs was associated with a thick layer of amorphous deposits. The contraceptive effect of the IUCDs was found to depend on the reaction of the host to the applied IUCDs rather than the type of device. The surface deposits were found to contain mainly calcium, phosphorus and magnesium.

[Apico-aortic shunts. Indications, results]

Seven children or adolescents aged 8 to 20 years (average 13.5 years) underwent implantation of an apico-aortic conduit from 1980 to June 1989. Eleven previous operations under cardiopulmonary bypass had been performed. The indications were recurrence of muscular subaortic stenosis and/or congenital valvular stenosis in 3 cases, and stenotic, previously implanted aortic valve prosthesis of small calibre in 4 cases. The preoperative left ventricular-aortic systolic pressure gradient was between 70 and 130 mmHg. The first two patients had a bioprosthetic valvulation and the 5 succeeding patients a St Jude Medical mechanical prosthesis. The early and late mortality was nil. The average follow-up period is 5, 6 years at present (range 6 months to 9 years). One patient had to undergo repeat valve replacement after 5 years for degenerescence of the porcine bioprosthesis implanted in the conduit. No other complications related to the conduit or valve were observed. At the endpoint of the study all patients were asymptomatic without treatment. Control echocardiographic data showed normalisation of the indices of left ventricular function. Apico-aortic conduits would seem to be a safe and effective technique for the treatment of recurrent severe obstruction of the left ventricular outflow tract.

[Surgical treatment of complete atrioventricular canal. Value of the "composite double patch" technic]

Between January 1, 1982 and January 1, 1988, 49 complete corrections of complete atrioventricular canal were performed in children aged from 4 months to 8 years. 41 were infants less than 2 years' old and 31 were less than one year old. In the last 35 patients the "composite double patch" technique was used, consisting of closure of the interventricular septal defect with a dacron patch, followed by closure of the ostium primum with a pericardial patch. The mitral cleft was left intact in the last 6 operations. The overall mortality rate was 35 p. 100 (17 patients). It was 23 p. 100 in infants under 1 year and 17 p. 100 in infants aged from 6 to 12 months at the time of surgery (p less than 0.01). Seven of the 35 children in whom the "composite double patch" technique was used died (20 p. 100). Only one early death was recorded among the last 15 children operated upon. Two reoperations were performed: one within one month of the first operation, the other 4 months later for residual mitral regurgitation with haemolysis. 32 children were followed up for periods of 2 months to 6 years, 10 of them for more than 3 years. Two late deaths occurred during the follow-up. Grade 2 or 3/4 residual regurgitation was found in 14 patients who have regular clinical and echocardiographic examinations.(ABSTRACT TRUNCATED AT 250 WORDS)