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S Kahraman

Publications and source records attributed to S Kahraman.

At least 19 recordsLinked to original sources
PubMed2006

The role of proinflammatory cytokine gene polymorphisms for development of insulin resistance after renal transplantation.

BACKGROUND: Insulin resistance, a frequent prediabetic metabolic complication after renal transplantation, is generally linked to immunosuppressive drugs including corticosteroids, cyclosporine (CsA) or tacrolimus, as well as to age, cadaveric donors and ethnic factors. Cytokines are known to be inflammation modulatory substances that contribute to metabolic derangements after transplantation. The present study investigated the effects of cytokine gene polymorphisms on insulin resistance in renal transplant recipients. PATIENTS AND METHODS: Sixty-one renal transplant recipients (37 men, 24 women; mean age: 39.3 +/- 10.8 years) who attended regular clinical visits without a known history of diabetes were enrolled in the study. All patients were on a regimen of steroid, CsA, and mycophenolate mofetil. Venous blood samples were collected for biochemical analyses after an overnight fast at 08:00 pm. CsA trough levels, C-reactive protein, and fibrinogen were also estimated. Additional 10 mL of blood was withdrawn into an ethylenediamine tetraacetic acid-containing tube to determine cytokine genotypes (tumor necrosis factor-alpha [TNF-alpha] -238 G/A, transforming growth factor-beta [TGF-beta] codon 10 -869 T/C). Insulin resistance was calculated by the homeostasis model assessment (HOMA) method using the values of fasting blood glucose (FBG) and insulin levels. Anthropometric indices as well as body height, weight, waist and hip circumferences were measured simultaneously to calculate body mass index (kg/m2) and waist-to-hip ratio. Impaired fasting glucose (IFG) was described as an FBG > or = 110 but < 126 mg/dL. RESULTS: IFG was detected in 27.9% of this study group. The HOMA index was significantly higher among patients with IFG compared with normal FBG (NoGT) (6.3 +/- 4.5 vs 3.7 +/- 1.5; P = .01). Neither FBG and insulin nor HOMA values correlated with antrophometric, metabolic, or inflammatory parameters. Cytokine genotype allele frequencies, age, sex, immunosuppressive and antihypertensive drug type and doses, CsA trough levels, and donor source (cadaveric/living) were similar for patients with IFG and NoGT. Mutant allele carrier genotypes (AA + GA) for TNF-alpha -238 G/A showed higher fasting insulin (14.0 +/- 7.9 vs 34.1 +/- 17.7 microIU/mL; P = .04) and HOMA (4.01 +/- 2.01 vs 7.95 +/- 5.44; P = .002) levels than GG homozygote subjects. FBG, HOMA, and other metabolic and anthropometric indices were similar between TGF-beta codon 10 -869 T/C genotypes. The daily dose of steroid (mg/d) and A allele frequency for TNF-alpha -238 G/A genotype were significant predictors of HOMA index in linear regression analysis. CONCLUSION: The present study revealed that beside the daily dose of steroids, TNF-alpha -238 G/A genotype may contribute to insulin resistance in renal transplant recipients. Further investigations may highlight the effects of cytokine gene heterogenity on insulin resistance in those patients.

Adult↗
PubMed2006

Human embryonic stem cell culture: current limitations and novel strategies.

Embryonic stem cells (ESC) are multipotent cells isolated from blastocyst-stage preimplantation embryos. Since their first culture in 1998, human ESC have revolutionized reproductive and regenerative medicine by allowing the establishment of detailed molecular and therapeutic models for certain metabolic pathways and life-threatening disorders. They also offer significant contributions to genetics and pharmacology in designing and analysing disease models that can be closer to in vivo than any other procedures available. However, the procedures by which they are obtained and manipulated also create intense ethical and social debates worldwide. This article discusses the current limitations and recent advances in isolation, culture and differentiation of human ESC from the laboratory perspective.

Cell Culture Techniques↗
PubMed2006

Preliminary FISH studies on spermatozoa and embryos in patients with variable degrees of teratozoospermia and a history of poor prognosis.

The aim of this study was to analyse to what extent sperm aneuploidy is associated with sperm morphology and subsequently with embryo aneuploidy. Fifty-nine men with variable degrees of teratozoospermia and previously poor assisted reproduction prognosis were included in the study. Samples from 10 normozoospermic men with proven fertility were used as controls. Individual spermatozoa were scored for chromosomes 13, 21 and for 18, X, Y separately. Compared with controls, 23 out of 59 cases (39.0%) were found to have increased sperm aneuploidy for at least one of the chromosomes analysed in a treatment cycle. Fifty-two patients underwent a treatment cycle and were documented according to the pregnancy and spermatozoa fluorescence in-situ hybridization results. A total of 121 previous unsuccessful assisted reproduction cycles of the cases were then retrospectively reviewed. In 23 of the latest cycles, preimplantation genetic diagnosis was applied to 106 cleavage stage embryos and 47 of 94 embryos analysed (50.0%) were found to be chromosomally abnormal. Furthermore, 16 of 47 (34.0%) embryos with chromosomal abnormality were carrying complex chromosomal defects. The results imply that increased aneuploidy is present in both spermatozoa and embryos in couples with severe male infertility with a history of repeated unsuccessful attempts. Therefore, proper genetic counselling should be considered in these cases.

Adult↗
PubMed2006

Embryo aneuploidy screening for repeated implantation failure and unexplained recurrent miscarriage.

Among other factors, chromosomal abnormalities that originate from gametogenesis and preimplantation embryonic development are thought to be one of the major contributing factors for early embryonic death and failure of pregnancy. However, so far, no non-invasive technique exists that allows the detection of the chromosomal complement of an oocyte or a developing embryo as a whole. Rather, by removing polar bodies/blastomeres, recent developments on preimplantation genetic diagnosis for aneuploidy screening (PGD-AS) have paved the way to detect and possibly eliminate the majority of chromosomally abnormal embryos, thereby increasing the chance of a healthy pregnancy. This article summarizes the origin and impact of chromosomal abnormalities on human reproduction in cases with repeated implantation failure (RIF) and unexplained recurrent miscarriage. It also discusses recent advances regarding the possible benefits of PGD-AS in such cases.

Abortion, Habitual↗
PubMed2006

Percutaneous endoscopic transforaminal lumbar discectomy: a critical appraisal.

Percutaneous endoscopic transforaminal lumbar discectomy (PETD) is one of the surgical techniques for the treatment of the lumbar disc herniations. Fenestration of the annulus and partial resection of the nuclear substance are achieved percutaneously by a posterolateral approach under local anaesthesia. The results of the first 42 patients are evaluated regarding the learning curve and indications for this procedure. The mean follow-up time was 15 months. Excellent and good results were evaluated as successful and the overall success rate is 77 %. All six patients with foraminal disc herniations in whom a free fragment could be removed had excellent results. Military personnel can return to work quickly without deficits with the use of this technique.

Adolescent↗
PubMed2006

Symptomatic epidural gas after open diskectomy: CT and MR imaging findings.

We report a case of symptomatic epidural gas accumulation after open diskectomy, causing lumbar radiculopathy. Surgery had been performed in a 44-year-old man for disk extrusion; however, he was readmitted to the hospital with increased lower back pain 5 months after the operation. CT and MR studies demonstrated accumulation of gas in the lumbar epidural space compressing the dural sac and nerve root. Symptoms disappeared after surgical removal of the gas.

Adult↗
PubMed2005

Strategies and clinical outcome of 250 cycles of Preimplantation Genetic Diagnosis for single gene disorders.

BACKGROUND: We report on our experience with preimplantation genetic diagnosis (PGD) for single gene disorders (SGDs), from 1999 to 2004, describing strategies and overall clinical outcome of 250 cycles in 174 couples for 23 different genetic conditions. METHODS: PGD cycles included 15 for autosomal dominant, 148 for autosomal recessive and 19 for X-linked SGDs. In addition, 68 cycles of PGD for SGDs were performed in combination with HLA matching. The strategy in each case used an initial multiplex PCR, followed by minisequencing to identify the mutation(s) combined with multiplex PCR for closely linked informative markers to increase accuracy. Linkage analysis, using intragenic and/or extragenic polymorphic microsatellite markers, was performed in cases where the disease-causing mutation(s) was unknown or undetectable. RESULTS: In 250 PGD cycles, a total of 1961 cleavage stage embryos were biopsied. PCR was successful in 3409 out of 3149 (92.4%) biopsied blastomeres and a diagnosis was possible in 1849 (94.3%) embryos. Four hundred and twenty-seven embryos were transferred in 211 cycles, resulting in 71 pregnancies (33.6% per embryo transfer), including 15 biochemical pregnancies, six spontaneous miscarriages, two ectopic pregnancies, which were terminated, and nine pregnancies which are still ongoing. The remaining pregnancies were confirmed to be unaffected and went to term without complications, resulting in the birth of 35 healthy babies. CONCLUSIONS: Minisequencing for mutation detection combined with multiplex fluorescence PCR for linkage analysis is an efficient, accurate and widely applicable strategy for PGD of SGDs. Our experience provides a further demonstration that PGD is an effective clinical tool and a useful option for many couples with a high risk of transmitting a genetic disease.

Adult↗
PubMed2004

Development and clinical application of a strategy for preimplantation genetic diagnosis of single gene disorders combined with HLA matching.

Preimplantation HLA matching has recently emerged as a tool for couples desiring to conceive a potential donor progeny for transplantation in a sibling with a life-threatening disorder. In this paper we describe a strategy optimized for preimplantation genetic diagnosis (PGD) of haemoglobinopathies combined with HLA matching. This procedure involves a minisequencing-based genotyping of HLA regions A, B, C and DRB combined with mutation analysis of the gene regions involved by mutation. Analysis of at least eight polymorphic short tandem repeat (STR) markers scattered through the HLA complex has also been included to detect potential contamination and crossing-over occurrences between HLA genes. The above assay can also be used for preimplantation HLA matching as a primary indication. The strategy was clinically applied for HLA matching in 17 cycles (14 for beta-thalassaemia, one for Wiscott-Aldrich syndrome and two for leukaemia). A reliable HLA genotype was achieved in 255/266 (95.9%) of the blastomeres. In total, 22 (14.8%) embryos were obtained that were HLA-matched with the affected siblings, 14 (9.4%) of which were unaffected and transferred back to the patients. Four clinical pregnancies were obtained, three of which (one twin, two singletons) are ongoing and were confirmed as healthy and HLA-identical with the affected children. Minisequencing-based HLA typing combined with HLA STR haplotyping has been shown to be a reliable strategy for preimplantation HLA matching. The major advantage of this approach is that the validation of a single assay can be done once and then used for the majority of the patients, reducing notably time needed for preclinical set-up of each case.

Blastocyst↗
PubMed2004

The results of aneuploidy screening in 276 couples undergoing assisted reproductive techniques.

Preimplantation genetic diagnosis for aneuploidy screening (PGD-AS) using sequential in situ hybridization was applied for aneuploidy testing in 276 couples with 282 ART cycles. Patients with advanced maternal age (AMA, n = 147), recurrent implantation failure (RIF, n = 48), repeated early spontaneous abortion (RSA, n = 32) and abnormal gamete cell morphology (AGCM, n = 55) including macrocephal sperm forms or cytoplasmic granular oocytes were included. Embryo biopsy was performed on day 3 in a calcium-magnesium-free medium by using a noncontact diode laser system. After fixation and enzymatic treatment, fluorescent in situ hybridization (FISH) was carried out on 1147 blastomeres with specific probes for chromosomes 13, 16, 18, 21 and 22 for AMA group, 13, 18, 21, X and Y for AGCM group and 13, 16, 18, 21, 22, X and Y for RIF and RSA groups respectively. The overall chromosomal abnormality rate in analyzed embryos was 40.9%, with no significant difference between AMA, RIF and RSA groups (p > 0.05). However, AGCM group presented a higher rate of chromosomal aneuploidies (57.4%) than the other three groups (p < 0.01). A total of 84% biopsied embryos presented cleavage in 24 h and embryo transfer was realized in 278 cycles. In four cycles, no chromosomally normal embryo was found for embryo transfer. A total of 88 pregnancies (31.6%) were achieved, 19.3% resulted in abortion and 63 healthy births were obtained, with a total of 93 babies born. Aneuploidy testing in couples with poor prognosis undergoing ART cycles is a useful tool to increase the chance of ART success. Furthermore, abnormal gamete cell morphology should be considered one of the major indications for PGD in ART programs as high aneuploidy rates were observed in this group.

Abortion, Habitual↗
PubMed2004

Prediction of renal allograft function with early Doppler ultrasonography.

INTRODUCTION: Doppler ultrasonography (USG) is an useful, noninvasive diagnostic tool for the management and follow-up of the transplanted kidney. However, it is believed that the value of Doppler USG is limited to discrimination of acute rejection episodes. We tested whether early Doppler USG findings were predictive of 1-month and 1-year allograft functions in noncomplicated renal transplant recipients (RTRs). PATIENTS AND METHODS: Resistive index (RI) and pulsatile index (PI) values obtained by doppler USG within the first week of transplantation were correlated with allograft function at 1 month and 1 year in 45 (10 women, 35 men, mean age: 27 years) noncomplicated cases. Patients with complications during the first posttransplant year were not included. RESULTS: There was a negative correlation between both RI and PI with creatinine clearance values at 1 month and at 1 year posttransplant. There was a significant decline in allograft function among cases with either RI > or = 0.7 or PI > or = 1.1. Patients with impaired allograft function have higher RI and PI values. CONCLUSION: Renal allograft survival is influenced by many factors. However, no reliable simple parameter has been identified to predict long-term outcome. Doppler USG performed during the early transplantation period with calculation of RI and PI may have a predictive value to forecast early and long-term outcomes of noncomplicated kidney transplants.

Adult↗
PubMed2004

Septic arthritis caused by Nocardia asteroides in a renal transplant recipient.

Although articular complications are common following renal transplantation, septic arthritis is not frequent. Previous bacterial infection in an another site is a consistent finding and the knee is the most often affected joint. We present a 30-year-old female renal transplant recipient with recurrent pulmonary infiltrates preceding septic arthritis of her left knee. Cultures of the aspirated synovial fluid yielded a gram-positive, rod-shaped bacterium later identified as Nocardia asteroides. The patient was treated with oral trimethoprim-sulfamethoxazole without any side effect. Nocardia is a rare but serious cause of infection in renal transplant recipients but there is no well-known predisposing factor. Recently mycophenolate mofetil has been implicated as a factor associated with Nocardia infections. Prolonged courses of treatment with sulphonamides are recommended.

Anti-Bacterial Agents↗
PubMed2004

Assessment of DNA fragmentation and aneuploidy on poor quality human embryos.

In human assisted reproduction, low embryo quality due to retarded growth and abnormal cellular morphology results in fewer embryos suitable for transfer. This study aimed to assess the extent of DNA fragmentation and aneuploidy in spare slow growing or arrested human embryos. In 19 assisted reproduction cycles, a total of 57 embryos unsuitable for embryo transfer were used for simultaneous apoptosis and aneuploidy assessment. Among them, 31 (54.3%) showed DNA fragmentation by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) analysis. Among 26 embryos that were negative for TUNEL, interpretable fluorescence in-situ hybridization (FISH) results were obtained for 25 embryos (96.2%). Sixteen embryos were detected to be chromosomally abnormal (64.0%); three were found to be chaotic, six had complex aneuploidy, six had complete monosomy and one was polyploid. The results show that a high level of DNA fragmentation and aneuploidy are common in embryos with slow growth and/or low quality. More detailed studies are needed to assess the effect of factors such as ovarian stimulation regimens and in-vitro culture conditions. Moreover, application of simultaneous TUNEL and FISH techniques can be informative regarding DNA integrity and aneuploidy.

Adolescent↗
PubMed2004

Clinical aspects of preimplantation genetic diagnosis for single gene disorders combined with HLA typing.

Preimplantation genetic diagnosis (PGD) for single gene disorders combined with human leukocyte antigen (HLA) matching has recently emerged as a therapeutic tool for stem cell transplantation in couples bearing an affected offspring. There may exist, however, several patient- or cycle-specific limitations for certain couples. This article documents data regarding experience of single gene disorders combined with HLA matching obtained at Istanbul Memorial Hospital, Turkey. The data were obtained from 20 couples undergoing 26 PGD-HLA cycles for thalassaemia (n = 23), Wiscott-Aldrich syndrome (n = 1) and acute lymphoblastic leukaemia (n = 2). A total of 206 embryos was biopsied on day 3 of embryo development and subsequently analysed. After the analysis, 26 (12.6%) of them were found to be both healthy and HLA compatible. In 16 embryo transfers performed, seven (43.7%) clinical pregnancies were obtained, one of which resulted in miscarriage. Ten of the 26 cycles started (38.4%) were cancelled due to a lack of suitable (mutation-free and/or HLA-compatible) embryos. The data suggest that application of PGD in combination with HLA typing is a promising therapeutic tool for an affected sibling.

Adult↗
PubMed2004

Effect of PGD on implantation and ongoing pregnancy rates in cases with predominantly macrocephalic spermatozoa.

Although its occurrence is rare, the presence of large headed or macrocephalic spermatozoa and increased chromosomal abnormality has recently been reported by several groups. Moreover, when intracytoplasmic sperm injection (ICSI) was performed with samples containing macrocephalic spermatozoa, lower fertilization and implantation rates result in poor clinical outcome. In order to evaluate the impact of preimplantation genetic diagnosis (PGD) on implantation and ongoing pregnancy rates in these couples, the results of 23 PGD cycles were compared with non-PGD cycles (n = 60) as well as cycles with absolute teratozoospermia (having zero normal morphology) with (n = 14) or without PGD (n = 66). Out of 82 embryos biopsied in the macrocephalic sperm group, abnormalities were detected in 46.4% of the embryos analysed. Most of the abnormalities were trisomies (37.0%) and complex aneuploidies (51.9%). A 33.3% pregnancy rate was achieved by selectively transferring euploid embryos after PGD with the statistically higher implantation rate of 25.0% compared with non-PGD cycles (IR: 12.3%, P < 0.01). Moreover, only one missed abortion (14.3%) was observed in the PGD group, whereas seven of the 15 pregnancies resulted in abortion in the non-PGD group (46.7%). Preliminary results indicate that patients should be counselled for increased chromosomal abnormality and a possible beneficial effect of eliminating chromosomally abnormal embryos with PGD on a bortion rates.

Abortion, Spontaneous↗
PubMed2004

State of the art of new data on the role of magnesium in brain injury: clinical interest of measurements of total and ionized magnesium.

Despite many research studies on traumatic brain injury, few markers have been applicable to diagnose trauma at tissue concentration. Today, the importance of the magnesium ion in posttraumatic homeostasis of brain is a well-known reality. Magnesium concentration affects a number of secondary injury factors including neurotransmitter release, ion changes, oxidative stress, protein synthesis, and energy metabolism. There are many experimental and clinical studies relating to magnesium status in brain injury. It was considered by some authors that only the total form of magnesium should be measured in brain injury. However, recent studies point out that measurement of the ionized form also aids in the intervention of patients with brain trauma. This review aims to explain the role of magnesium in brain injury and to assess the real status of magnesium through pertinent tests.

Brain Injuries↗
PubMed2003

Morphological and cytogenetic analysis of intact oocytes and blocked zygotes.

We examined cytological and cytogenetic parameters of 1076 oocytes and 385 zygotes that failed to develop post in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Out of 1076 oocytes, 894 (83%) arrested oocytes showed a first polar body and were thus assumed arrested at metaphase II while the remainder showed no polar body. In the group of oocytes with a polar body, 20.5% had an abnormal karyotype. Cytologically, premature sperm chromosome condensation was noted in 28.3% of uncleaved oocytes. This high PCC can be explained by the different grades of oocyte maturity from one center to another. Oocytes from older women showed no increased aneuploidy but did show increased premature chromosome condensation. Analysis by classical technique of 220 uncleaved zygotes showed 91 with highly condensed chromosomes, 53 with asynchrony of condensation, 31 with pulverized chromosomes, and 45 arrested at the first somatic metaphase. Out of 385 arrested zygotes, 165 were explored by in situ hybridization. FISH using a set of 7 chromosome-specific probes showed aneuploidy in the chromosomes analyzed (13, 16, 18, 21, 22, X, Y) in 21.8% of blocked zygotes (19-25% depending on morphology). Extrapolating to other chromosomes, we expect that a vast majority of blocked zygotes and oocytes probably carry chromosome abnormalities. These data demonstrate the contributions of chromosome disorder in early embryo development blocking and implantation failure. Certainly, the issue of cytoplasm and nuclear immaturity and their relation to each other and to chromosome abnormalities provides a fertile area for future investigation in ART.

Adult↗
PubMed2003

Decolorization and bioremediation of molasses wastewater by white-rot fungi in a semi-solid-state condition.

Molasses wastewater (vinasse; the by-product of distillation of fermented sugar) was decolorized and its chemical oxygen demand (COD) was reduced in static cultivation using the fungi Coriolus versicolor, Funalia trogii, Phanerochaete chrysosporium and Pleurotus pulmonarius ('Pleurotus sajorcaju'). The effect of cotton stalk on decolorizing and COD removing capability of four fungi was determined. In the entire concentration range tested (10-30%), wastewater was effectively decolorized by C. versicolor and F. trogii. Cotton stalk addition stimulated the decolorization activity of all fungi. The utilization of cotton stalk represents several advantages due to its function as an attachment place and as a source of nutrients; its use also reduces process costs.

Biodegradation, Environmental↗