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Biomedical subjects

Bülent Kaya

Publications and source records attributed to Bülent Kaya.

6 recordsLinked to original sources
PubMed2006

Analysis of UV-stimulated recombination in the Drosophila SMART assay.

The UV component of solar radiation is classified into UVA (320-400 nm), UVB (290-320 nm), and UVC (200-290 nm). Although all three types of UV light are capable of damaging biological systems, the earth's atmosphere filters out UVC, and a portion of UVB. In this study, we evaluated the induction of mutation and recombination by different wavelengths of UV light in the wing spot test of Drosophila melanogaster (Somatic Mutation and Recombination Test, SMART). Third-instar larvae that were trans-heterozygous for the third chromosome recessive markers, multiple wing hairs (mwh) and flare-3 (flr(3)), were exposed to different doses of UVA (at 365 nm), UVB (at 312 nm) or UVC (at 254 nm), and transferred to standard Drosophila culture medium. Feeding ended with pupation of the surviving larvae, and the genetic changes induced in the somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Point mutation, chromosome breakage, and mitotic recombination produce single spots, while twin spots are produced only by mitotic recombination. Exposure to 500-4,000 J/cm(2) UVA did not increase the frequency of mutant spots. UVB doses of 200, 250, 300, 350, and 400 J/cm(2) increased the frequency of all categories of spots, indicating that UVB was potentially both mutagenic and recombinogenic. Assays run in balancer-heterozygous flies (which are insensitive to recombination) indicated that the fraction of mutants in trans-heterozygous flies due to recombination increased from 48.57% at 200 J/cm(2) UVB to 98.30% at 400 J/cm(2) UVB. While 140-480 J/cm(2) of UVC was not genotoxic, UVC produced a strong toxic response at doses higher than 140 J/cm(2). The results of this study indicate that UVB was much more active than UVC or UVA in the SMART assay, and that UVB was highly recombinogenic.

Animals↗
PubMed2004

Evaluation of the genotoxicity of four herbicides in the wing spot test of Drosophila melanogaster using two different strains.

In the present study, the herbicides bentazone, molinate, thiobencarb and trifluralin were evaluated for mutagenic and recombinagenic effects using the wing spot test of Drosophila melanogaster (somatic mutation and recombination test, SMART). Both standard (ST) and high-bioactivation (HB) fly crosses were used, the latter cross is characterised by a high sensitivity to promutagens and procarcinogens. Three-day-old larvae, transheterozygous for the multiple wing hairs (mwh, 3-0.3) and flare-3 (flr(3), 3-38.8) genes, were chronically fed with six different concentrations of each herbicide. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Point mutation, chromosome breakage and mitotic recombination produce single spots; while twin spots are produced only by mitotic recombination. Bentazone, usually considered as a non-mutagen, gave positive results in the wing spot test with the high-bioactivation cross. Molinate, about which information on mutagenic effects is inconclusive, gave positive responses in both the standard and the high-bioactivation crosses, while the other thiocarbamate, thiobencarb, gave positive results only in the standard cross and at the highest concentration tested (10 mM). Finally, trifluralin, one of the most widely studied herbicides for genotoxic effects, gave positive results in the wing spot test with both crosses. Apart from the interest of the results found in the genotoxic evaluation of the four selected herbicides, our results also contribute to extend the existing database on the Drosophila wing spot test, and corroborate the utility of the use of high-bioactivation strains for the genotoxic evaluation of xenobiotics.

Animals↗
PubMed2003

[The comparison of incision and drainage with skin excision and curettage in the treatment of acute pilonidal abscess].

BACKGROUND: To compare therapeutic values of incision and drainage, with skin excision and curettage in surgical treatment of the patients with acute pilonidal abscess. METHODS: In this prospective study, patients with acute pilonidal abscess were divided into two groups. The first group of patients were treated with incision and drainage and the second with skin excision and curettage. Two treatment modalities were compared in terms of healing time, time of returning to active work and development of chronic pilonidal sinus rates with chi-square and student-t test. RESULTS: Development of chronic pilonidal sinus rate was 76% in incision and drainage group and 24% in skin excision and curettage group (p<0.001). Healing time and time of returning to active work were 27 and 35 days in skin excision and curettage group, 19 and 26 days in incision and drainage group, respectively (p<0.001). CONCLUSION: Skin excision and curettage, which is associated with lower rates of development of chronic pilonidal sinus, may be the treatment of choice in acute pilonidal abscess.

Abscess↗
PubMed2002

Genotoxicity is modulated by ascorbic acid. Studies using the wing spot test in Drosophila.

The ability of ascorbic acid (Vitamin C) to modulate the genotoxic action of several mutagens was investigated in the wing spot test of Drosophila melanogaster. In this assay, 3-day-old transheterozygous larvae for the multiple wing hairs (mwh, 3-0.3) and flare (flr, 3-38.8) genes were treated with three reference mutagenic compounds, namely cobalt chloride (CoCl2), 4-nitroquinoline 1-oxide (4-NQO) and potassium dichromate (K2Cr2O7). The results obtained show that the three reference mutagens tested were clearly genotoxic in the Drosophila wing somatic mutation and recombination test (SMART). None of the three concentrations tested of ascorbic acid (25, 75 and 250mM) induced significant increases in the frequency of the mutant clones recorded. When co-treatment experiments with ascorbic acid were carried out, different results were found. Thus, ascorbic acid was effective in reducing the genotoxicity of K2Cr2O7 virtually to the control level; on the contrary, it did not show any antigenotoxic effect on the genotoxicity of 4-NQO. Finally, co-treatments with CoCl2 and ascorbic acid show a significant increase in the frequency of mutant clones over the values obtained with CoCl2 alone.

4-Nitroquinoline-1-oxide↗
PubMed2002

Acute appendicitis during pregnancy.

BACKGROUND: To analyze the diagnosis and surgical treatment of acute appendicitis during pregnancy. METHODS: The records of 24 pregnant patients who underwent surgery with preliminary diagnosis of acute appendicitis between January 1990 and July 2000 were reviewed retrospectively. RESULTS: Between January 1990 and July 2000, there were 31,480 deliveries and the incidence of acute appendicitis was 1/1,312. Twenty patients had pathologically proven acute appendicitis (83.3%). Of the remaining 4 patients, one had hemorrhagic ovarian cyst, one had ovarian cyst rupture and in two cases no surgical pathology was diagnosed. Gestational stage at the diagnosis was first trimester in 7 patients, second trimester in 12 patients and third trimester in 5 patients. Five patients had abortions and premature delivery occurred in 2 patients. CONCLUSION: Diagnosis of acute appendicitis is difficult in pregnancy. Delay in diagnosis and surgery results in increase in complications. Emergency surgical intervention should be performed when acute appendicitis is suspected during pregnancy.

Adolescent↗