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Biomedical subjects

B Uslu

Publications and source records attributed to B Uslu.

15 recordsLinked to original sources
PubMed2006

T-cell-rich B-cell lymphoma of the spleen presenting with severe hypersplenism.

We report a 19-year-old woman who was presented with B-symptoms, massive splenomegaly, hepatomegaly and hypersplenism. She underwent diagnostic/therapeutic splenectomy. Microscopically, the spleen showed a vaguely micronodular and diffuse proliferation of lymphoid cells in the white pulp that also involved the red pulp. On immunohistochemical staining, this proliferation consisted predominantly of CD3(+), CD7(+) small T cells with the presence of a minor population of CD15(-),CD30(-), CD20(+) large atypical B cells. A liver biopsy also showed a similar morphology to that seen in the spleen. After splenectomy, only the pancytopenia improved. A combined immunochemotherapy regimen (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) was utilized, which resulted in a complete remission.

Adult↗
PubMed2006

Electrochemical methods for determination of the protease inhibitor indinavir sulfate in pharmaceuticals and human serum.

Indinavir sulfate is an inhibitor of the human immunodeficiency virus (HIV) protease. The aim of this study was to determine indinavir levels in serum and pharmaceuticals, by means of electrochemical methods using the hanging mercury drop electrode (HMDE). Indinavir exhibited irreversible cathodic waves over the pH range 2.00-12.00 in different supporting electrolytes. The current-concentration plot was rectilinear over the range from 8 x 10(-7) M to 8 x 10(-6) M with a correlation coefficient of 0.996 for differential pulse voltammetry (DPV) and 8 x 10(-7) M to 1 x 10(-5) M with correlation of 0.999 M for osteryoung square ware voltammetry (OSWV) in Britton-Robinson buffer at pH 10.00. The wave was characterized as being irreversible and diffusion-controlled. The proposed methods were fully validated and successfully applied to the determination of indinavir in capsules and spiked human serum samples with good recoveries. The repeatability and reproducibility of the methods as well as precision and accuracy (such as supporting electrolyte, serum samples) were determined. No electroactive interferences from the endogenous substances were found in serum samples.

Capsules↗
PubMed2004

Validated RP-hPLC method for the assay of zalcitabine in drug substance, formulated products and human serum.

A HPLC method for zalcitabine determination in bulk form, pharmaceutical dosage forms and human serum has been developed and validated. The proposed method was conducted using a reverse phase technique, and UV monitoring at 265 nm. The mobile phase consisted of methanol: 0.01 M NaH2PO4 (85:15; v/v) adjusted to pH 4.62 with 1 M NaOH. The detector response was linear in the range of 0.015-50 microg mL(-1). The limit of detection and the limit of quantification of the procedure were 0.0066 microg mL(-1) and 0.022 microg mL(-1), respectively. The retention time was 2.5 min for zalcitabine and 3.5 min for the internal standard. No interferences from tablet additives were observed and analysing tablets containing zalcitabine proved the applicability of the method. This method was also applied for the determination of zalcitabine in spiked human serum samples.

Calibration↗
PubMed2004

Anodic adsorptive stripping voltammetry of the antihypertensive drug candesartan cilexetil at a glassy carbon electrode.

The electrochemical behaviour of candesartan cilexetil (CND) was investigated in an acetonitrile: supporting electrolyte mixture (30% acetonitrile) in the pH range 1.5-11.00 by cyclic, linear sweep, differential pulse (DPV), adsorptive stripping differential pulse (AdSDPV), square wave (SWV) and adsorptive stripping square wave (AdSSWV) voltammetric techniques. CND exhibited one wave and one peak to the anodic direction. The oxidation process was found to be irreversible and adsorption controlled. To obtain good sensitivity, the instrumental and accumulation variables were studied using DPV and SWV techniques. Two linear calibration plots were obtained for both techniques. The detection limits were 9.15 x 10(-7) M and 7.94 x 10(-6) M for AdSDPV and AdSSWV, respectively. The method was validated and successfully applied for the analysis of CND tablets.

Antihypertensive Agents↗
PubMed2001

Intraoperative management of the thyroid gland in laryngeal cancer surgery.

OBJECTIVE: To determine if it is necessary to perform a hemithyroidectomy routinely with all total laryngectomies or if it should be reserved for selected cases. DESIGN: A retrospective analysis of 215 cases who had been operated on due to laryngeal cancer in our clinic between 1985 and 1999. SETTING: In only 182 cases, hemithyroidectomy and isthmectomy were performed together with laryngeal surgery. Of these, 98% were male. Their ages ranged between 42 and 70 years. The tumour was located in the supraglottic region in 93 (51%) and in the glottic region in 24 (13%) cases. In 65 cases (36%), the tumour was transglottic. Twenty cases of transglottic tumours (31%) and 3 cases of glottic tumours (12.5%) were found to have subglottic extension. METHODS: Total laryngectomy with unilateral or bilateral neck dissection and hemithyroidectomy on the tumour side plus isthmectomy were performed on all patients. On the pathologic specimens, subglottic extension was measured anteriorly and posteriorly from the free edges of the vocal cords. The specimens were stained with hematoxylin and eosin and examined under a light microscope. MAIN OUTCOME MEASURES: With glottic and transglottic carcinomas, the need for thyroidectomy may be based on the intraoperative assessment of the thyroid gland. In subglottic carcinomas, a hemithyroidectomy should routinely be performed. There may be no need to perform thyroidectomy in all total laryngectomy cases. RESULTS: The thyroid gland was invaded by squamous cell carcinoma in only 2 cases (1%). Both of these cases were transglottic tumours staged as T3 and T4 and had a subglottic extension more than 1 cm. CONCLUSIONS: We recommend routine hemithyroidectomy and isthmectomy during total laryngectomy only in cases with subglottic extensions more than 1 cm or thyroid cartilage invasion with tumour. In the other cases, assessment of extralaryngeal invasion and thyroid gland invasion by the tumour will determine whether thyroidectomy should be performed.

Adult↗
PubMed2001

Determination of olsalazine sodium in pharmaceuticals by differential pulse voltammetry.

The electrochemical oxidation of olsalazine sodium was investigated by cyclic, linear sweep, differential pulse and square wave voltammetry using glassy carbon disc electrode in different buffer systems. Best results were obtained for the determination of olsalazine using the differential pulse voltammetric technique in phosphate buffer at pH 7.0. The electroactive species exhibits a diffusion-controlled voltammetric wave and its differential pulse peak current shows a linear dependence on olsalazine concentration in the range between 2 x 10(-6) M and 2 x 10(-4) M. This relationship has been applied to the determination of olsalazine in commercial capsule dosage forms. The recovery study shows good accuracy and precision for the assay developed. A UV spectrophotometric assay is also reported for comparison.

Aminosalicylic Acids↗
PubMed2001

Simultaneous determination of melatonin and pyridoxine in tablet formulations by differential pulse voltammetry.

A method has been developed for the simultaneous determination of melatonin (MT) and pyridoxine hydrochloride (PY) in pharmaceutical dosage forms by differential pulse voltammetry, based on the oxidation of both drugs at a glassy carbon electrode. Cyclic and linear scan voltammetry were used to examine the influence of pH, nature of the buffer, scan rate and concentration. The results in 0.5 M H2SO4 with 20% methanol allowed a method to be developed for the determination of MT and PY simultaneously and in the presence of each other in the ranges 2 x 10(-5)-8 x 10(-5) and 2 x 10(-5)-4 x 10(-4) M, with the detection limits of 5.86 x 10(-6) and 2.45 x 10(-6) M, respectively. The proposed method was successfully applied to the commercial tablets containing this drug combination without any interference by the excipients.

Antioxidants↗
PubMed2000

Study on electrooxidation of cefadroxil monohydrate and its determination by differential pulse voltammetry.

In this work electrooxidation of cefadroxil monohydrate was investigated using a glassy carbon electrode depending on pH and supporting electrolyte. It was shown that the direct determination of the substance from capsules and in oral suspension could be made by differential pulse voltammetry (DPV). UV and first derivative UV spectrophotometric methods are also proposed as comparative methods.

Cefadroxil↗
PubMed1998

Determination of terbutaline based on oxidation by voltammetry.

A voltammetric study of the oxidation of terbutaline has been carried out at an activated glassy carbon electrode. The compound was oxidized irreversibly at high positive potential. The response was evaluated with respect to pH, scan rate, nature of the buffer and other variables. The peak current, at about 0.8 V (versus a saturated calomel electrode), was proportional to the terbutaline concentration in the range of 8 x 10(-6)-8 x 10(-4) M in phosphate buffer pH 6.0. This method was applied, without any interferences from the excipients, to determine the drug in a tablet dosage form.

Adrenergic beta-Agonists↗
PubMed1996

Anodic voltammetry of fluphenazine at different solid electrodes.

The electrochemical behaviour of fluphenazine based on its oxidation at platinum and glassy carbon electrodes was investigated by linear sweep and cyclic voltammetry. The influence of pH, concentration, nature of the buffer and scan rate was carefully examined. At both electrodes, three anodic steps (representing an irreversible oxidation) were obtained. The method was applied to the determination of fluphenazine in sugar-coated tablets.

Antipsychotic Agents↗
PubMed1996

Voltammetric determination of imipramine hydrochloride and amitriptyline hydrochloride using a polymer-modified carbon paste electrode.

In this paper the voltammetric behaviors of imipramine.HCl and amitriptyline. HCl, which are both tricyclic antidepressants, were investigated using a carbon paste electrode, modified by the addition of poly(N-vinylimidazole), in various solutions of different pHs. It was shown that the current density for imipramine increased with modification of the carbon paste electrode and amitriptyline, which was electroinactive with the normal carbon paste electrode, became electroactive on the modified electrode. The optimum conditions for the quantitive determination of imipramine.HCl and amitriptyline.HCl were determined and statistical analysis of the linear relationship between current and concentration is given. The method was applied for the determination of these substances in the pharmaceutical dosage forms.

Amitriptyline↗
PubMed1983

Effect of fluoride on collagen synthesis in the rat.

Thirty-six young rats were used to determine the effect of the fluoride on collagen synthesis in healing of fracture. Eighteen rats received 100 ppm fluoride per day, the other 18 were not given fluoride and were used as controls. Then the tibiae of the 36 rats were successively fractured and the animals killed. That is, the first 14 animals of either group were killed one a day, and then the remaining four animals were killed on days 21, 28, 35, and 45 as the tibiae were fractured. Collagen synthesis of the callus was examined histochemically and histologically. In the fluoride-treated group, collagen synthesis was found to be defective, while it was normal in the controls.

Animals↗