Paracrine effects of living human bone particles on the osteogenic differentiation of mesenchymal stem cells

Bone autografting remains the clinical model of choice for resolving problematic fractures. The precise mechanisms through which the autograft promotes bone healing are unknown. The present study examined the hypothesis that cells within the autograft secrete osteogenic factors promoting the differentiation of mesenchymal stem cells (MSCs) into osteoblasts. Particles of human bone ("chips") were recovered at the time of joint replacement surgery and placed in culture. Then, conditioned media were added to cultures of human, adipose-derived MSCs under both basal and osteogenic conditions. Contrary to expectation, medium conditioned by bone chips reduced the expression of alkaline phosphatase and strongly inhibited mineral deposition by MSCs cultured in osteogenic medium. Real time PCR revealed the inhibition of collagen type I alpha 1 chain (Col1A1) and osteopontin (OPN) expression. These data indicated that the factors secreted by bone chips inhibited the osteogenic differentiation of MSCs. However, in late cultures, bone morphogenetic protein-2 (BMP-2) expression was stimulated, suggesting the possibility of a delayed, secondary osteogenic effect.

Detection of methamphetamine, methylenedioxymethamphetamine, and 3,4-methylenedioxy-N-ethylamphetamine in spiked plasma by HPLC and TLC

HPLC and TLC methods were developed for separation and detection of some amphetamine analogs: methamphetamine (MA); 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy"); and 3,4-methylenedioxy-N-ethylamphetamine (MDEA) in spiked plasma samples. The methods are based on purple chromogens formed by displacement reaction of these secondary aliphatic amine-bearing drugs with 7,7,8,8-tetracyanoquinodimethane at 80 degrees C for 25 min. For HPLC, both normal phase (silica gel) and RP (C18) columns were used. With the former, good detection limits in plasma were obtained with a 6 min run: 70, 100, and 500 ng/mL for MDMA, MA, and MDEA, respectively. For TLC, hexane-chloroform (1 + 9) and benzene-diethyl ether-petroleum ether (40-60 degrees)-acetonitrile-ethyl methyl ketone (2 + 3.5 + 3.5 + 0.5 + 0.5) were used as mobile phases for silica gel 60 TLC and cyano-bonded silica gel HPTLC plates, respectively. The former offered more sensitive results than the latter. Influence of evaporation steps on recovery and interferences for the HPLC and TLC methods were investigated. The developed methods are selective, simple, and easily applicable.

Determination of linezolid in human breast milk by high-performance liquid chromatography with ultraviolet detection

A rapid and simple HPLC method was developed for the determination of linezolid (LNZ) in human breast milk after a simple protein precipitation with methanol. The chromatographic separation was achieved on a C18 column (5 microm, 250 x 4.6 mm id) using a mobile phase of acetonitrile-10 mM acetic acid (25:75, v/v) at a flow rate of 1 mL/min. The LNZ peak was measured by photodiode array detection at 250 nm. The calibration graph was linear over the range of 0.5-20.0 microg/mL. The limits of detection and quantitation were found to be 0.1 and 0.5 microg/mL, respectively. The precision of the assay and the recovery of LNZ from breast milk at three different concentrations were assessed. The intraday and interday RSD values were found to be < 5%. The mean absolute recovery was 85.33%. The developed method was successfully applied to the determination of LNZ in breast milk obtained from the breastfeeding mother after oral administration of LNZ.

Spectrophotometric and spectrofluorimetric methods for the determination of pregabalin in bulk and pharmaceutical preparation

Two new, sensitive and selective spectrofluorimetric and spectrophotometric methods have been developed for the determination of the gamma-amino-n-butyric acid derivative pregabalin (PGB) in bulk drug and capsule. Pregabalin, as a primary amine compound, reacts with 7-chloro-4-nitrobenzofurazon (NBD-Cl) which is a highly sensitive fluorogenic and chromogenic reagent used in many investigations. According to this fact, spectrophotometric and spectrofluorimetric methods for the determination of pregabalin in capsules were developed for the first time. The relation between the absorbance at 460 nm and the concentration is rectilinear over the range 0.5-7.0 microg mL(-1). The reaction product was also measured spectrofluorimetrically at 558 nm after excitation at 460 nm. The fluorescence intensity was directly proportional to the concentration over the range 40-400 ng mL(-1). The method was applied successfully to the determination of this drug in pharmaceutical dosage form. The mean recovery for the commercial capsules was 99.93% and 99.96% for spectrophotometric and spectrofluorimetric study, respectively. The suggested procedures could be used for the determination of PGB in pure and capsules being sensitive, simple and selective.

Spectrophotometric Determination of Dopaminergic Drugs Used for Parkinson's Disease, Cabergoline and Ropinirole, in Pharmaceutical Preparations

Simple and reproducible spectrophotometric methods have been developed for determination of dopaminergic drugs used for Parkinson's disease, cabergoline (CAB) and ropinirole hydrochloride (ROP), in pharmaceutical preparations. The methods are based on the reactions between the studied drug substances and ion-pair agents [methyl orange (MO), bromocresol green (BCG) and bromophenol blue (BPB)] producing yellow colored ion-pair complexes in acidic buffers, after extracting in dichloromethane, which are spectrophotometrically determined at the appropriate wavelength of ion-pair complexes. Beer's law was obeyed within the concentration range from 1.0 to 35 microg ml(-1). The developed methods were applied successfully for the determination of these drugs in tablets.

A selective high-performance liquid chromatography method for the determination of reboxetine in bulk drug and tablets

Reboxetine is used as a selective noradrenaline reuptake inhibitor for the treatment of major depressive disorders. It is effective in the treatment of severe depression and safer to use than traditional tricyclic antidepressants. In this study, a novel, simple, and rapid stability-indicating high-performance liquid chromatography (HPLC) method for reboxetine methansulfonate was successfully developed and validated for the assay of tablets. The method was used to quantify reboxetine in tablets; it employed a C18 column (150 x 4.6 mm id) with an isocratic mobile phase consisting of methanol-phosphate buffer (pH 7, 0.02 M; 55 + 45, v/v) at a flow rate of 1.0 mL/min. Reboxetine was detected by an ultraviolet detector at 277 nm. The retention time of reboxetine was about 4.5 min. The developed HPLC method was validated with respect to linearity, precision, sensitivity, accuracy, and selectivity. The method was linear over the concentration range 1-50 microg/mL (r = 0.9999). The limits of detection and the quantitation of reboxetine were 0.1 and 0.3 microg/mL, respectively. The relative standard deviation values for intraday and interday precision were 0.78-1.01 and 1.08-1.37%, respectively. Selectivity was validated by subjecting a stock solution of reboxetine to neutral, acid, and alkali hydrolysis, as well as oxidation, dry heat treatment, and photodegradation. The peaks of the degradation products did not interfere with the peak of reboxetine. The results indicated that the proposed method could be used in a stability assay. The proposed method was successfully applied to the determination of reboxetine in tablets. Excipients present in the tablets did not interfere with the analysis.

Determination of gabapentin in human plasma and urine by high-performance liquid chromatography with UV-vis detection

A simple and reliable high-performance liquid chromatographic (HPLC) method with UV-vis detection has been developed and validated for the determination of gabapentin (GBP) in human plasma and urine. The clean up of the sample was carried out by solid-phase extraction with C18-cartridge. After the clean up procedure, the samples were pre-column derivatizated with 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS). A chromatographic separation was achieved on a C18 column with a mobile phase consisting of acetonitrile and 10mM orthophosphoric acid (pH 2.5) with isocratic elution (35:65). Baclofen was used as an internal standard (I.S.). The method developed for GBP was linear over the concentration range of 0.05-5.0 microg/ml and 0.1-10.0 microg/ml for plasma and urine, respectively. The method is precise (relative standard deviation, R.S.D. <4.05%) and accurate (relative mean error, RME <0.15%); mean absolute recoveries were 72.21% for plasma and 72.73% for urine.

A highly sensitive spectrofluorometric method for the determination of a new antidepressant drug, reboxetine, in tablets

A highly sensitive, selective, and rapid spectrofluorometric method has been developed for the determination of reboxetine (REB) in tablets. The method is based on derivatization with 7-chloro-4-nitrobenzofurazan. The product showed an absorption maximum at 476 nm and a fluorescence emission peak at 533 nm in ethyl acetate. The optimum conditions of the reaction were investigated, and it was found that the reaction proceeded quantitatively at pH 8.5, 70 degrees C in 5 min. The calibration graph is rectilinear over the range of 0.02-0.40 microg/mL. The relative standard deviation values for intraday and interday precision were 0.40-0.93 and 0.54-1.37%, respectively. The proposed method was applied to the assay of REB in tablets. Mean recovery of REB from the tablets ranged between 99.91-100.20%. The results were compared statistically with those obtained by a method reported in the literature. The method is sensitive, simple, and selective, and can be used for routine quality control analysis.

Spectrophotometric determination of certain antidepressants in pharmaceutical preparations

Simple and reproducible spectrophotometric methods have been developed for determination of sertraline, fluoxetine, and venlafaxine in pharmaceutical preparations. The methods are based on the reactions between the studied drug substances and ion-pair agents (bromothymol blue, bromocresol green, or bromophenol blue) to produce yellow-colored ion-pair complexes in acidic buffers. After extracting in chloroform, the ion-pair complexes are spectrophotometrically determined at the optimum wavelength. Optimizations of the reaction conditions were carried out. Beer's law was obeyed within the concentration range from 1 to 15 microg/mL. The molar absorptivity, Sandell sensitivity, and detection and quantification limits were also determined. The developed methods were applied successfully for the determination of these drugs in some available commercial preparations. The results were compared statistically with those obtained from reported high-performance liquid chromatography methods.

Determination of Paroxetine in Human Plasma by High-Performance Liquid Chromatography Using 7,7,8,8-Tetracyanoquinodimethane as the Derivatization Reagent

A selective and sensitive reversed-phase HPLC method was developed for the determination of the antidepressant paroxetine in plasma. The method is based on the purple chromogen formed by a displacement reaction of paroxetine with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in acetonitrile at 80 degrees C for 20 minutes. For the assay, the drug was extracted from 1 mL of plasma with chloroform and, after sample alkalinization, derivatized with TCNQ; then the reaction mixture was directly injected into a C18 column. Desipramine was used as internal standard. The mobile phase was acetonitrile-water (70:30) at a flow-rate of 1.0 mL/min, and the derivatives were eluted at 13.1 and 15.5 minutes for paroxetine and desipramine, respectively, and detected at 567 nm. Calibration curve was found linear over the range of 20-400 ng/mL, and the detection limit was 2 ng/mL at a signal-to-noise ratio of 3/1. Recoveries determined for 3 concentrations range between 81.3% and 88.1%. Intraday and interday relative standard deviation values were found to be within 3.8%-13.5% and 8.2%-14.6%, respectively. With this developed method, a pharmacokinetic study was performed for paroxetine.

Spectrophotometric methods for the determination of the antidepressant drug paroxetine hydrochloride in tablets

Simple, sensitive, and accurate visible spectrophotometric methods are described for the determination of paroxetine hydrochloride (PA) in tablets. Among them, the first 3 methods are based on the ion-pair complexes of PA formed with bromothymol blue (BTB), bromophenol blue (BPB), and bromocresol green (BCG) in aqueous acidic buffers. The complex species extracted into chloroform were quantitatively measured at 414 nm with BTB and BCG and at 412 nm with BPB. Beer's law was obeyed over the concentration ranges of 2-20, 2-16, and 2-16 microg/mL, respectively. The fourth method described is based on a coupling reaction between PA and 7-chloro-4-nitrobenzofurazon (NBD-Cl) in borate buffer, pH 8.5, in which a yellow reaction product that was measured at 478 nm was formed. The Beer's law range for this method was 2-10 microg/mL. The last method developed describes the interaction of PA base, as an n-electron donor, with 7,7,8,8-tetracyanoquinodimethane (TCNQ), as a pi-acceptor, in acetonitrile to give blue-colored TCNQ- radical anion with absorption maxima at 750 and 845 nm. Measured at 845 nm, the absorbance-concentration plot was rectilinear over the range of 1.5-15 microg/mL. The new methods developed were successfully applied to the determination of PA in tablets without any interference from common tablet excipients. The results of the methods were in good agreement with those obtained with an official liquid chromatographic method. This report describes first colorimetric methods for the determination of PA.

Ondansetron does not block tramadol-induced analgesia in mice

Tramadol is a weak opioid agonist and an inhibitor of the reuptake of noradrenaline and serotonin. This study was undertaken to assess a possible pharmacological interaction of ondansetron, a serotonin-3 (5-hydroxytryptamine-3, 5-HT3) antagonist, and tramadol in an animal model for acute pain. Sixty-three male albino mice were randomly given saline, tramadol (10, 20, and 40 mg kg(-1)), ondansetron (1, 2, and 4 mg kg(-1)), or ondansetron (1, 2, and 4 mg kg(-1)) and tramadol (20 mg kg(-1), given 10 min after ondansetron injection) intraperitoneally. Each mouse was assessed twice for tail-flick latency before saline or drug administration and 15, 30, 60, 90, and 120 min thereafter. Tramadol (10 mg kg(-1)) had no effect on pain threshold levels of mice, but tramadol doses of 20 or 40 mg kg(-1) increased pain threshold levels in a dose-dependent manner (p < 0.01 for 20 mg kg(-1) and p < 0.001 for 40 mg kg(-1)). Ondansetron doses of 1, 2, or 4 mg kg(-1) alone had no effect on pain threshold levels of mice. Tramadol (20 mg kg(-1)) and ondansetron (1, 2, and 4 mg kg(-1)) increased pain threshold levels at all doses (p < 0.001 for 1 and 2 mg kg(-1) ondansetron and p < 0.01 for 4 mg kg(-1) ondansetron). The pain threshold levels of mice given tramadol (20 mg kg(-1)) alone or tramadol and ondansetron (p > 0.05 for 1, 2, and 4 mg kg(-1)) were similar. Our results indicate that ondansetron-a 5-HT3 selective antagonist-does not decrease the analgesic effectiveness of tramadol in mice, which may be the result of different mechanisms involving 5-HT3 receptors.

Spigelian hernia associated with strangulation of the small bowel and appendix

Spigelian hernia is a rare lateral ventral abdominal hernia. These clinically elusive hernias are treacherous and have a real risk of strangulation. We present a patient with a strangulation of the small bowel and appendix in a right spigelian hernia, which was accurately demonstrated by spiral computerised tomography preoperatively and successfully treated with primary suturing reinforced with polypropylene mesh. With a high index of suspicion and the use of modern radiological technique, these "bewildering" hernias can be diagnosed and repaired relatively safely.

Analytical methods for the quantitative determination of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors in biological samples

Published analytical methods for the quantitative determinations of presently available five 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors ("statins"), lovastatin, simvastatin, pravastatin, fluvastatin and atorvastatin, are reviewed for therapeutic drug monitoring purpose in patients. Almost all assay reviewed are based on high-performance liquid chromatography or gas chromatography. Some purification steps (liquid-liquid extraction, solid-phase extraction, etc.) have been used before they are submitted to separation by chromatographic procedures and they are detected by various detection methods like UV, fluorescence and mass spectrometry. This review shows that most method may be used quantitative determination of statins in plasma and they are suitable for therapeutic drug monitoring purpose of these drugs.

The antinociceptive effect of tramadol-venlafaxine combination on the paw withdrawal threshold in a rat model of neuropathic pain

The combination of venlafaxine and tramadol was compared with the single use of these agents to investigate the antinociceptive effect on paw withdrawal latency (PWL) to paw pressure in rats with neuropathic pain. Rats were divided into 4 groups: group 1 received saline (0.2 ml i.p.); group 2 received venlafaxine (22 mg/kg i.p.); group 3 received tramadol (20 mg/kg i.p.); and group 4 received venlafaxine + tramadol. No statistically significant changes were observed in the saline and venlafaxine groups with respect to PWL in the lesioned paw. However, tramadol produced a significant antinociceptive effect on the lesioned paw at 30 min compared with the saline and venlafaxine groups. A more potent antinociceptive effect was observed in the tramadol + venlafaxine group, beginning at 60 min and lasting for 1 h. The combination of venlafaxine + tramadol was more effective in increasing the pain threshold in this animal model of neuropathic pain than either of these drugs administered alone.

Agmatine produces antinociception in tonic pain in mice

Agmatine is an endogenous polyamine metabolite formed by decarboxylation of L-arginine. In this study, the effect of agmatine on tonic pain was compared to its effect on phasic pain by using the formalin and tail-flick (TF) tests in mice. When administered intraperitoneally (ip), agmatine (37.5-300 mg/kg) exhibited a decrease in nociceptive behaviours in the first and second phase of the formalin test, which is a tonic pain model. The alpha(2) adrenoceptor antagonist yohimbine blocked the effect of agmatine in Phase 2 but did not change its effect in Phase 1. In the TF test, there was no significant change in the behaviour of agmatine-administered (75-300 mg/kg) animals. As a result, agmatine appears to have an analgesic effect on tonic rather than phasic pain, and alpha(2) receptors seem partly to have a role in the antinociceptive effect of agmatine on tonic pain.

Effect of nabumetone treatment on vascular responses of the thoracic aorta in rat experimental arthritis

Nabumetone is a nonsteroidal anti-inflammatory (NSAI) drug which is known to cause less gastrointestinal damage than other NSAI drugs. This study was performed to evaluate whether nabumetone treatment might alter the vascular aberrations related to inflammation in a rat model of adjuvant-induced arthritis. Nabumetone treatment (120 or 240 mg x kg(-1) x day(-1), orally) was initiated on the 15th day of adjuvant inoculation and continued for 14 days. Arthritic lesions, vascular contractile and relaxant responses and gastroduodenal histopathological preparations were evaluated 29 days after adjuvant inoculation. The contractile responses of aortic rings to phenylephrine and KCl were increased in grade 2 arthritic rats. In grade 3 arthritis only the phenylephrine contractility was decreased. The relaxant responses to acetylcholine and sodium nitroprusside were decreased in grades 2 and 3. In healthy rats, nabumetone did not change the vascular responses. After treatment of arthritic rats with nabumetone, both the contractile and relaxant response of the aortic rings returned to normal, and arthritic score and paw swelling were reduced. Gastroduodenal histopathology did not show erosions or ulcers in any of the groups. In conclusion, nabumetone improved the systemic signs and vascular alterations in experimental arthritis without showing any gastrointestinal side effects.

The antinociceptive effect of leukotriene D(4) receptor antagonist, MK-571, in mice: possible involvement of opioidergic mechanism

The effect of a leukotriene D(4) receptor antagonist, (3-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl(3-dimethyl amino-3-oxo propyl)thio)methyl)thio) propanoic acid (L-660,711; MK-571), was investigated on nociceptive responses in mice using three different assays: acetic-acid-induced abdominal constrictions, formalin response and tail-flick test. MK-571 (8-32 mg/kg, i.v.) produced dose-dependent protection against acetic-acid-induced abdominal constriction (ED(50)=30 mg/kg). The compound (10-80 mg/kg, i.p.) was also effective, in a dose-dependent manner, on the second phase of the formalin response (ED(50)=26 mg/kg). However, it had no effect on the first phase of the formalin response and in the tail-flick test. Naloxone (1 mg/kg, i.v.), an opioid antagonist, almost completely blocked the antinociceptive effect of MK-571 in both acetic-acid-induced abdominal constriction and the second phase of the formalin test. These results provide evidence for an antinociceptive action of MK-571 at peripheral sites and suggest that opioid mechanisms are involved.

The relationship between pupil diameter and pain by the administration of morphine and antidepressant drugs in mice

Because the pain sensation is subjective, it is difficult to evaluate the responses to analgesic drugs. Some analgesics that affect the central nervous system are known to change the pupil diameter. The pupil diameter is a more objective criterion that shows the drug effect. We studied the relation between the pupil diameter and analgesia responses to morphine and antidepressants by using the selective micro-receptor agonist morphine (2 and 4 mg/kg), the noradrenaline reuptake inhibitor desipramine (7.5 and 10 mg/kg), the mixed serotonergic and noradrenergic uptake inhibitor and cholinergic receptor antagonist amitriptyline (2.5 and 5 mg/kg), and the selective serotonin reuptake inhibitor sertraline (2.5 and 5 mg/kg) in mice. Both monocular microscopy to assess pupil measurement and the hot-plate test to assess nociceptive thresholds were used in the same animals. We found that morphine played an important role in both mydriasis and analgesia, whereas amitriptyline and desipramine had a greater effect on pupil response than on nociception. Sertraline produced antinociception without causing a change in pupil diameter. As a result, although the pupil response is an important criterion in evaluating the analgesic effect of morphine, it is not possible to put forward the same criterion for the antidepressant drugs. Because different neurotransmitters are involved in pupil and pain mechanisms of antidepressant drugs, it is difficult to evaluate the analgesic response with the pupil diameter.

Systemic absorption of gentamicin in penile prosthesis operations

Irrigation with antibiotic solutions is frequently used in penile prosthesis surgery to avoid infection. We carried out a prospective study to determine the degree of absorption of gentamicin after intracavernous irrigation in 10 patients who underwent penile implantation surgery. All obtained values were below the toxic level of 10 micrograms/ml and decreased gradually within a few hours. We concluded that highly concentrated gentamicin solutions could be used with safety for intracavernous irrigation.

Effects of protein energy malnutrition on circulating thyroid hormones

The effect of protein energy malnutrition (PEM) in the children on serum levels of total thyroxine (TT4), total triodothyronine (TT3) and thyrotropin (TSH) were evaluated. There were 107 children aged 2 to 60 months in the malnutrition group and 54 healthy age and sex matched controls. Serum TT4 and TT3 were all reduced in the malnutrition group. This decrease in TT3 was more significant (p < 0.01) in severe malnutrition than in mild PEM. Serum TSH levels in the malnutrition and control groups were similar. These results suggest that the children remained euthyroid and represent an adaptive response to protein energy malnutrition.

A new electrochemical method for the production of stable ascorbate free radicals

A new method for the production of ascorbate free radicals is established. The radical is produced from ascorbate in deionized water by applying constant potential electrolysis under a nitrogen atmosphere. Prior to electrolysis, a cyclic voltammogram (CV) of the ascorbic acid was obtained. Electrolysis potentials were selected as the oxidation peak potential of the ascorbic acid obtained by CV. The detection of the radical was done by electron spin resonance (esr) and uv spectroscopies.

Lifetime of peroxyl radicals of poly(U), poly(A) and single-and double-stranded DNA and the rate of their reaction with thiols

Peroxyl radicals of poly(U), poly(A), and single- and double-stranded DNA have been produced by photolysing H2O2 in oxygenated aqueous solution in presence of the substrates. The peroxyl radicals are formed by the reaction of OH radicals with the polynucleotides followed by addition of oxygen. The lifetime of the peroxyl radicals and the rate constant of their reactions with the thiols cysteamine, glutathione and dithiothreithol have been measured by time-resolved e.s.r. spectroscopy. The unusually long lifetimes range from 0.2 to 3.3 s. The activation energy for the decay for all four substrates is 10.3 +/- 1 kcal/mol (43 kJ mol-1). The reaction rate constants with the thiols range from k = 0.8 X 10(4) to 1.3 X 10(5) dm3 mol-1 s-1. The reactions of the thiols with the peroxyl radical of poly(U) are known to prevent strand break formation. This shows that the peroxyl radicals of poly(U) observed by e.s.r. are intermediates in the pathway leading to strand break formation.