PubMed Health⌕ Search

Biomedical subjects

S Cakir

Publications and source records attributed to S Cakir.

13 recordsLinked to original sources
PubMed2005

The effect of pre-operative conventional and hyperfractionated radiotherapy schedules on wound healing and tensile strength in rats: an experimental study.

We examined the effects of pre-operative conventional and hyperfractionated radiotherapy schedules on wound healing and tensile strength in 90 female Wistar rats weighing between 182 and 240 g. The animals were randomized into three groups (n = 30 each). Group I was sham-irradiated. Group II (conventional) received 20 daily fractions of 200 cGy, to a total dose of 4000 cGy. Group III (hyperfractionated) received 40 fractions of 120 cGy, twice daily, to a total dose of 4800 cGy. Four weeks after radiotherapy, incision and primary repair with simple suturing was performed on one side of the neck. Twenty-one days after wounding, all the rats were sacrificed. Non-parametric Kruskal-Wallis and Mann-Whitney U-tests were used for the statistical analysis of wound tensile strength. The chi-squared test was used for the statistical analysis of the histopathologic findings. The hyperfractionated group had a significantly lower tensile strength than that of the control group (P = 0.03, z = -2.18). According to the histopathologic findings, fibrosis was increased significantly in the hyperfractionated group as compared to the other groups (P = 0.038, chi2 = 6.52). Hyperfractionated radiotherapy significantly reduced the wound tensile strength in the early evaluation period as compared to the control group.

Animals↗
PubMed2005

MYCOTOX and aflatoxicosis in quails.

1. This study was to evaluate the toxic effects of aflatoxin (AF) on growth performance of quail, and to determine the preventive efficacy of MYCOTOX (oxicinol, tymol, micronised yeast). 2. One hundred and eighty 1-d-old quail (Coturnix coturnix japonica) of both sexes were weighed and randomly divided into 4 experimental groups each with 5 replicates of 9 birds. 3. There were 4 dietary treatments: (1) control with 0 mg AF/kg diet and 0% MYCOTOX; (2) 0 mg AF/kg diet and 0.5% MYCOTOX; (3) 2.5 mg AF/kg diet and 0% MYCOTOX; (4) 2.5 mg AF/kg diet plus 0.5% MYCOTOX. The chicks were maintained on these treatments to 3 weeks of age. Quail consumed the diets and water ad libitum. 4. Body weight (BW) gains in groups receiving AF alone were the lowest at all periods. Feed intake was lowest in the group consuming the AF diet. The addition of MYCOTOX to the AF diet did not prevent or reduce the toxic effects of AF on feed intake at any time period. Feeding diets containing MYCOTOX alone did not change feed intake significantly. With the exception of the 1 to 7 d period, feed conversion of chicks fed the AF diet was similar to those of the other experimental groups. 5. Bursa of Fabricius weight decreased, whereas the relative weights of liver, kidney and spleen increased in quail consuming diets containing AF and AF plus MYCOTOX. Liver colour was normal in the control and MYCOTOX alone group, but was lighter in groups fed AF. 6. The results indicated that MYCOTOX was not effective in preventing the deleterious effects of AF.

Aflatoxins↗
PubMed2004

Redox behaviour of cysteine in the presence of ammonium trioxovanadate(V).

The interaction of ammonium trioxovanadate(V) with cysteine in aqueous solution was studied by cyclic voltammetry and absorption spectroscopy techniques. In the absence of cysteine, the cyclic voltammogram (CV) of ammonium trioxovanadate(V) solution in 0.1 M phosphate buffer (pH 7) gave two peaks at -0.130 V (reversible) and -0.400 V (irreversible). These peaks (-0.130 V, -0.400 V) can be attributed to V(V)/V(IV) and V(IV)/V(III) redox processes, respectively. In the presence of cysteine at low scan rate (40 mV/s), the peak at -0.780 V, which is assigned to the irreversible reduction of free cystine, was observed. In addition, the reduction peak of the disulfidic anion S(2)(2-) was seen at -0.650 V. Under aerobic conditions, the peaks of the disulfidic anion S(2)(2-) and free cystine are well separated. From electronic spectra of ammonium trioxovanadate(V) and cysteine mixtures, LMCT transition associated with V(V)-cyteine complex was obtained at 743 nm. The stoichiometry (ML(2)) and stability constant (log beta(1:2)=6.67) of V(V)-cysteine complex were determined by means of mole ratio method.

Cysteine↗
PubMed2004

Prognostic significance of seizure in patients with glioblastoma multiforme.

BACKGROUND: Several prognostic factors have been described but there are few studies evaluating the prognostic importance of seizure in patients with glioblastoma multiforme (GBM). AIMS: To evaluate the prognostic importance of seizure at the time of the diagnosis of glioblastoma multiforme (GBM) and compare it with other known prognostic factors. SETTINGS AND DESIGN: Between January 1994 and December 2000, 81 patients underwent irradiation for intracranial GBM at our institution. The criteria for inclusion in this study were biopsy-proven GBM, being treated for primary disease. Seventy-six patients were retrospectively evaluated and the remaining five patients could not be enrolled due to lack of details. MATERIAL AND METHODS: The prognostic importance of age, sex, performance status, a history of seizure at diagnosis, extent of surgery, radiotherapy field and dose were studied. STATISTICAL ANALYSIS: The Kaplan-Meier method, the Log rank test, the Cox proportional hazard model and the Mann-Whitney U test were used for statistical analysis. RESULTS: Survival at first and second years was 19.74% and 4.81%, respectively. Univariate analysis revealed age, performance status, history of seizure, and radiotherapy dose as significant prognostic factors and with multivariate analysis age, history of seizure and radiotherapy dose were positive prognostic factors. CONCLUSION: This study concluded that in GBM, history of seizure prior to diagnosis of GBM was a positive prognostic factor.

Adult↗
PubMed2003

Electrochemical monitoring of the interaction of doxorubicin with nicotinamide and Fe(III) ions under aerobic and anaerobic conditions.

The interaction of doxorubicin with Fe(III) ions and nicotinamide (NA) has been followed by square-wave voltammetry, cyclic voltammetry and UV-VIS. spectroscopy techniques at aerobic and anaerobic conditions. Fe(III)-doxorubicin complex gives a 1-electron reversible step at -0.494 V and a shoulder at 580 nm. Further, the Fe(III)-doxorubicin complex was found to be more stable at aerobic conditions. In the presence of NA, an intermediate (NA-Fe(III)-DQ) forms at -0.462 V under aerobic conditions. Because of the formation of this intermediate, nicotinamide may reduce the cardiotoxic effect of doxorubicin and cause to its detoxification.

Doxorubicin↗
PubMed2000

Polymorphism of M factors in populations of the housefly, Musca domestica L., in Turkey.

M factors, which determine maleness in Musca domestica, were found on the second, third, fourth and fifth linkage groups in housefly populations of Turkey. As in European populations, the male-determining factor was more frequently located on linkage group III (MIII). Some males homozygous or double heterozygous for M factors were identified. Deviations from a 1:1 sex ratio in favour of males, as well as mosaics for somatic marker mutations and sexual mosaics (gynandromorphs), were also observed. The results reveal an extensive polymorphism in the sex-determining system.

Animals↗
PubMed1998

The male-determining activity on the Y chromosome of the housefly (Musca domestica L.) consists of separable elements.

In the common housefly, the presence or absence of a male-determining factor, M, is responsible for sex determination. In different strains, M has been found on the Y, on the X, or on any of the five autosomes. By analyzing a Y-autosomal translocation and a ring-shaped, truncated Y chromosome, we could show that M on the Y consists of at least two regions with M activity: One of them can be assigned to the short arm of the Y chromosome (MYS), which is largely C-banding negative, the other region lies on the C-banding positive long arm of the Y, including the centromeric part (MYL). Each region alone behaves as a hypomorphic M factor, causing many carriers to develop as intersexes of the mosaic type instead of as males. When introduced into the female germ line by transplantation of progenitor germ cells (pole cells), the MYS shows an almost complete maternal effect that predetermines 96% of the genotypic female (NoM) animals to develop as males. In contrast, the MYL has largely lost its maternal effect, and most of the NoM animals develop as females. Increasing the amount of product made by either of the two hypomorphic M factors (by combining the MYS and MYL or two MYS) leads to complete male development in almost every case. We thus assume that the Y chromosome carries at least two copies of M, and that these are functionally equivalent.

Animals↗
PubMed1995

Multivariate analysis of prognostic factors in 75 patients with soft tissue sarcoma.

The results of 75 patients with soft-tissue sarcomas treated by the combination of local surgical excision plus postoperative radiotherapy are reported. Thirty-five tumors were situated in the extremities, 32 in the trunk, and eight in the head and neck. Twenty-eight tumors were high grade, 33 intermediate and 14 low grade. Sixty-two patients had complete resections (wide or marginal) and 13 incomplete resections (intralesional). Radiation was administered with a shrinking-field technique (median total dose, 64 Gy; range, 50-78). Twenty-five patients developed local recurrence (33%). The 5-year local control rate was 67%. On univariate analysis, a tumor site other than extremity (p < 0.05), unfavorable histology (p < 0.01), and incomplete resection (p < 0.01) were poor risk factors for local recurrence. When multivariate analysis were performed, only incomplete resection (relative risk (RR) 7.2) remained a poor risk factor. The 5-year overall survival rate was 50.5% for the entire group. Following a univariate analysis of host tumor and treatment-related factors, a tumor site other than extremity (p < 0.05), high tumor grade (p < 0.01) unfavorable histology (p < 0.05), and incomplete tumor resection (p < 0.01) were found to significantly increase the risk of further tumor death. Multivariate analysis found high tumor grade (RR 5.6), and incomplete resection (RR 7) to be independent poor risk factors for survival.

Adult↗
PubMed1995

Thallium-201 uptake in myositis ossificans. Potential pitfall in diagnosis.

Myositis ossificans is primarily a disorder of adolescents or adults, whereby an area of muscle mass undergoes progressive ossification. Its radiographic and scintigraphic appearances have been well documented. In this paper, a case of histopathologically demonstrated myositis ossificans in the proximal thigh with unexpected TI-201 accumulation was presented.

Adult↗
PubMed1993

Causes of syncope in children: a prospective study.

We prospectively evaluated 80 patients with syncope, between January 1991 and January 1992 to determine the causes of syncope in children. There were 35 male and 45 female patients, whose mean age was 10.5 years. A single syncopal attack had occurred in 30 patients and multiple attacks in 50. A cardiovascular cause was established in 22 (27.5%) patients and a noncardiovascular cause in 36 (45%). The cause remained unknown in 22 patients (27.5%). Vasovagal syncope was the leading cause of syncope in these patients with an incidence of 32.5%. These findings suggest that every patient who has even one syncopal attack should be promptly investigated since the underlying cause could be a life-threatening one.

Adolescent↗
PubMedDate not supplied

Variation of droplet sizes during the formation of microcapsules from emulsions.

The size distributions of microcapsules are important in determining the surface area over which the contents of the microcapsules are released. The size distribution is generally not normal around the mean, but biased toward smaller capsule sizes, forming a mode around some characteristic diameter. In order to assess the factors effective in determining this characteristic drop size, size distribution analyses were carried out photographically at each stage of the complex coacervation process. In addition, the emulsion drop size distributions were investigated as a function of stirring rate, stirring time and phase ratio. The results agreed qualitatively with the theory of isotropy but were an order of magnitude smaller. This theory is valid for Newtonian liquids. Elongational stresses could be operative with large-sized macromolecules and a mechanism was proposed based on variation of elongational stresses with velocity and rates of extension. Elongational viscosities measured for the gelatin solutions supported the proposed mechanism.

Capsules↗