Biomedical subjects

M Yalçin

Publications and source records attributed to M Yalçin.

7 recordsLinked to original sources

PubMed2005

The adsorption kinetics of the cationic dye, methylene blue, onto clay.

In this study, adsorption kinetics of a cationic dye, methylene blue, onto clay from aqueous solution with respect to the initial dye concentration, temperature, pH, mixing rate and sorbent dosage were investigated. In order to understand the adsorption mechanism in detail, zeta potentials and the conductivities of clay suspensions at various pH (1-11) and cation exchange capacity (CEC) were measured. Porosity and BET surface area of clay studied were determined. The results showed that the adsorption has been reached to equilibrium in 1 h. It was found that the amount adsorbed of methylene blue increases with decreasing temperature and also with increasing both sorbent dosage and increasing initial dye concentration. Adsorption capacity decreases with increasing pH, except for the natural pH (5.6) of clay suspensions. The adsorption kinetics of methylene blue has been studied in terms of pseudo-first-order, pseudo-second-order sorption and intraparticle diffusion processes thus comparing chemical sorption and diffusion sorption processes. It was found that the pseudo-second-order mechanism is predominant and the overall rate of the dye adsorption process appears to be controlled by the more than one-step.

Adsorption↗

PubMed2004

Determination of adsorptive properties of clay/water system: methylene blue sorption.

In this study, adsorption of methylene blue onto clay was investigated. The effect of adsorption time and temperature on the adsorption process was studied. To reveal the adsorptive characteristics of the clay studied, porosity and BET surface area measurements were made. It was observed that the adsorption capacity decreases with increasing temperature, and adsorption equilibrium was attained within 1 h. It was found that the data fit well to Langmuir, Halsey, Henderson, and Harkins-Jura models but experimental data deviate significantly from BET and Freundlich models at especially high concentrations. Furthermore, isosteric adsorption enthalpy and entropy are calculated as -7.99 kJ mol(-1) and 25.41 JK(-1)mol(-1), respectively.

Journal Article↗

PubMed2004

Missed opportunities for tetanus vaccination in pregnant women, and factors associated with seropositivity.

The aim of this study was to identify the seroprevalance rate of tetanus and to determine missed opportunities for tetanus vaccination. Two hundred and twenty-seven female volunteers who were hospitalized following delivery participated in the study. Blood samples were analyzed using enzyme-linked immunoassay to measure tetanus antibody levels. In addition, a questionnaire was used to investigate the factors associated with vaccination status. Sixty-five percent of the study participants had safe protective levels of antibodies. Factors associated with antibody level were age, level of education and number of doses. Only 25.7% of women who received antenatal care (ANC) had received tetanus vaccinations. Women who received ANC from primary healthcare facilities were more likely to have been vaccinated than those who received ANC from hospitals or private practice (P < 0.05). Factors associated with both tetanus vaccination and immunizations in pregnant women should be further investigated by qualitative and quantitative studies. Knowledge, attitude and practice surveys of mothers and healthcare providers on provision of the tetanus vaccine to pregnant women need to be undertaken urgently.

Adolescent↗

PubMed2003

Successful treatment of acquired haemophilia with prednisolone therapy.

Acquired hemophilia is a rare, life threatening coagulopathy in adults caused by the development of autoantibodies against to factor VIII. No general consensus exists on the best therapeutic approach. We report here a case that presented with extensive cutaneous and mucosal bleedings due to factor VIII inhibitors and treated successfully with steroid therapy alone but complicated with a life threatening thromboembolic attack during her follow up. In conclusion, corticosteroids are "cost effective therapy" associated with high inhibitor elimination rates and although recurrence of inhibitor in a patient with factor VIII inhibitor is an expected clinical situation thrombosis risk should also be considered.

Adrenal Cortex Hormones↗

PubMed2003

Congenital lobar emphysema: a clinicopathologic evaluation of 14 cases.

Controversy still exists concerning the diagnosis and treatment of congenital lobar emphysema (CLE). Although surgical removal of the affected lobe is the most commonly accepted form of treatment, detection of milder or even asymptomatic cases is usually followed by a more conservative management of patients, i. e. non-surgical treatment and follow-up. We therefore decided to evaluate our patients with CLE, placing special emphasis on treatment and diagnostic techniques. We also evaluated quantitative analyses of alveolar diameters. Fourteen children with CLE were analysed retrospectively, including age, sex, clinical picture, localisation, diagnostic and surgical modalities and histopathologic diagnosis. The alveolar diameters of affected lobes were compared with those of the lobectomised patients with other non-obstructive respiratory diseases. All children but one had severe respiratory distress as an initial symptom. All patients, except newborns, had a history of pulmonary infection. All cases underwent thoracic CT examination as the main radiologic method. In all of the patients, only one lobe was affected. We found an obvious mediastinal shift and atelectasis of adjacent lobes due to compression of the affected lobe. The affected lobe was therefore surgically removed in all of the children. In one case, we had to carry out a partial lobectomy to reduce the duration of the operation, due to an intraoperative fall of oxygen saturation. All of the children had an uneventful clinical course postoperatively. The alveolar diameters of the cases with CLE were significantly greater than those of the control patients. We think that the majority of cases with CLE have too severe respiratory distress to avoid surgical removal of affected lobe. Conservative management should be reserved only for patients with milder symptoms or no distress at all.

Child, Preschool↗

PubMed1996

IL-8 in pleural effusion.

Interleukin-8 (IL-8) is a recently described potent chemotactic factor that may be involved in the pathogenesis of pleural effusions. To understand the actual mechanisms mediating the inflammatory response, changes in cellular components and IL-8 level in pleural fluid of different aetiologies were evaluated. Thirty-four patients (19 male, 15 female) with a mean age of 46 +/- 22 years (range 16-92) were included in the study. Of these, 13 had tuberculous pleural effusion, seven had empyema/parapneumonic pleural effusion, and 14 had malignant pleural effusion (seven adenocarcinoma, three ovarian carcinoma, two lymphoma, one chronic myeloid leukaemia, and one small cell carcinoma) with positive cytology. Differential cell counts in the pleural fluid were obtained using cytocentrifuge preparations. The concentrations of IL-8 in pleural fluid were measured by the ELISA method. Interleukin-8 was detected in all 34 pleural fluid samples. The serum IL-8 level was analysed only in the empyema/parapneumonic pleural effusion group. The mean IL-8 levels of tuberculous, empyema/parapneumonic, and malignant pleural effusions were 1420 +/- 1049 pg ml-1, 4737 +/- 2297 pg ml-1, and 1574 +/- 1079 pg ml-1, respectively. The IL-8 levels in the empyema/parapneumonic group were significantly raised over malignant and tuberculous groups (P < 0.02). The mean pleural fluid neutrophil counts in tuberculous, empyema/parapneumonic and malignant pleural effusions were 315 +/- 575 cells mm-3, 11,136 +/- 12,452 cells mm-3, and 635 +/- 847 cells mm-3, respectively (P < 0.003). There was a significant positive correlation between pleural IL-8 levels and neutrophil counts (r = 0.46, P < 0.006). The levels of IL-8 in paired samples of serum and pleural fluid in the empyema/parapneumonic effusion group were compared, and the concentration of IL-8 was higher in the pleural effusion than serum (means, 4737 +/- 2297 pg ml-1 and 130.0 +/- 62.5 pg ml-1, respectively, P < 0.03). There was a significant negative correlation between IL-8 concentrations in serum and pleural fluid (r = -0.80, P < 0.03). This data suggests that production of IL-8 in pleural effusion may play a key role in initiation and maintenance of inflammatory reactions, especially in empyema/parapneumonic pleural effusions. It may offer the basis for introduction of novel anti-inflammatory agents in treatment.

Adolescent↗

PubMedDate not supplied

Selective IgA deficiency and ankylosing spondylitis.

A man with an ankylosing spondylitis (AS) and selective IgA deficiency is described. There have been several reports in the literature indicating coexistence of AS with selective IgA deficiency. As it is suggested in the literature, we believe that selective IgA deficiency is a poor prognostic factor in AS.

Humans↗