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S Aksoy

Publications and source records attributed to S Aksoy.

At least 55 records · Page 3Linked to original sources
PubMed1999

Concordant evolution of a symbiont with its host insect species: molecular phylogeny of genus Glossina and its bacteriome-associated endosymbiont, Wigglesworthia glossinidia.

Many arthropods with restricted diets rely on symbiotic associations for full nutrition and fecundity. Tsetse flies (Diptera: Glossinidae) harbor three symbiotic organisms in addition to the parasitic African trypanosomes they transmit. Two of these microorganisms reside in different gut cells, while the third organism is harbored in reproductive tissues and belongs to the genus Wolbachia. The primary symbiont (genus Wigglesworthia glossinidia) lives in differentiated epithelial cells (bacteriocytes) which form an organ (bacteriome) in the anterior gut, while the secondary (S) symbionts are present in midgut cells. Here we have characterized the phylogeny of Wigglesworthia based on their 16S rDNA sequence analysis from eight species representing the three subgenera of Glossina: Austenina (=fusca group), Nemorhina (=palpalis group), and Glossina (=morsitans group). Independently, the ribosomal DNA internal transcribed spacer-2 (ITS-2) regions from these species were analyzed. The analysis of Wigglesworthia indicated that they form a distinct lineage in the gamma subdivision of Proteobacteria and display concordance with their host insect species. The trees generated by parsimony confirmed the monophyletic taxonomic placement of Glossina, where fusca group species formed the deepest branch followed by morsitans and palpalis groups, respectively. The placement of the species Glossina austeni by both the traditional morphological and biochemical criteria has been controversial. Results presented here, based on both the ITS-2 and the symbiont 16S rDNA sequence analysis, suggest that Glossina austeni should be placed into a separate fourth subgenus, Machadomyia, which forms a sister-group relationship with the morsitans group species.

Animals↗
PubMed1999

Elevated serum progesterone level on the day of human chorionic gonadotropin administration does not adversely affect implantation rates after intracytoplasmic sperm injection and embryo transfer.

OBJECTIVE: To evaluate the association between serum P levels on the day of hCG administration and the outcome of intracytoplasmic sperm injection (ICSI). DESIGN: Retrospective case study. SETTING: Assisted reproduction unit of a tertiary care private hospital. PATIENT(S): Nine hundred eleven ICSI cycles that proceeded to ET were studied. INTERVENTION(S): The decision to administer hCG was based on serum E2 levels and follicle size. Serum P was measured from frozen sera obtained on the day of hCG administration. Cycles were stratified according to serum P levels of <0.9 ng/mL (n = 298) or > or =0.9 ng/mL (n = 613). This cutoff level was selected because it yielded the highest sensitivity and specificity according to a receiver operator characteristic curve. MAIN OUTCOME MEASURE(S): Implantation and clinical pregnancy rates. RESULT(S): In cycles with high serum P levels, more oocytes were retrieved and more embryos were available for transfer. Clinical pregnancy rates per ET in the low and high P groups were 36.9% and 45.4%, respectively (P<.05). The implantation rate per embryo was similar in the two groups (14.9% and 16.4%, respectively, in cycles with P levels <0.9 vs > or =0.9 ng/mL). Abortion rates were 22.7 and 25.8%, respectively (P>.05). CONCLUSION(S): Our data showed no adverse effect of high serum P levels on the day of hCG administration on implantation rates after ICSI and ET.

Adult↗
PubMed1999

Tissue tropism, transmission and expression of foreign genes in vivo in midgut symbionts of tsetse flies.

Tsetse flies (Diptera: Glossinidae) harbour three different symbiotic organisms in addition to the pathogenic African trypanosomes they transmit. The two gut-associated symbionts (primary, P; secondary, S) are enteric and are nutritionally required, whereas the third microorganism Wolbachia (family Rickettsiaceae) affects the reproductive biology of the insects it infects. The bacteriome-associated P-symbiont (Wigglesworthia glossinidia) displays a concordant phylogeny with its host tsetse species, whereas midgut S-symbionts characterized from distant tsetse have identical 16S rDNA sequences and therefore may either represent recent independent acquisitions or horizontal transfer between species. The S-symbionts have been cultured in vitro and a genetic transformation system has been developed. Here we report on their density and tissue tropism in different species (G. m. morsitans, G. p. palpalis, G. austeni and G. brevipalpis) and on their maternal route of transmission to tsetse progeny. Using a bacterium-specific PCR-assay, the S-symbionts were found primarily in the midgut, haemolymph, milk gland and in G. palpalis also in salivary glands of teneral flies. In older flies these infections were found to spread to other tissues including muscle, testes and fat body. The S-symbionts were transformed to express the marker gene product, Green Fluorescent Protein (GFP) in vitro. When the recombinant symbionts were introduced into the haemoceal of fertile female flies via intrathoracic microinjection, they were detected in the intrauterine progeny, indicating that haemolymph may provide a possible route for their transmission. The implications of these results for symbiont-host interactions and for transgenic strategies in tsetse are discussed.

Animals↗
PubMed1999

In-vitro culture of spermatozoa induces motility and increases implantation and pregnancy rates after testicular sperm extraction and intracytoplasmic sperm injection.

The aim of this study was to determine the effect of 24-h in-vitro culture of testicular spermatozoa in recombinant follicle stimulating hormone (recFSH) supplemented medium versus simple medium on sperm motility, and to analyse the outcome of intracytoplasmic sperm injection (ICSI) of such spermatozoa. A total of 143 positive testicular sperm extraction procedures in men with non-obstructive azoospermia was evaluated prospectively. Extracted testicular tissue samples were randomized to be cultured in vitro for 24 h in simple medium or recFSH supplemented media. ICSI was performed with spermatozoa cultured in recFSH (n = 73) or in simple medium (n = 70). Sperm motility following in-vitro culture, embryo quality after ICSI, and implantation and pregnancy rates were assessed. Of the 898 MII oocytes available in the recFSH group, 646 (71.9%) were injected with spermatozoa showing either twitching or progressive motility. However, only 29.1% of the oocytes in the simple medium group (245/841) were injected with motile spermatozoa (P < 0.05). Fertilization rate (68.8 versus 42.1%), implantation rate per embryo (20.1 versus 13.2%), and clinical pregnancy rate (47. 9 versus 30%) were significantly increased in the recFSH group compared with the simple medium group respectively (P < 0.05). In conclusion, in-vitro culture with recFSH appears to increase the motility of testicular spermatozoa, thus increasing the success of ICSI.

Cells, Cultured↗
PubMed1999

Sandflies (Diptera: Psychodidae) associated with epidemic cutaneous leishmaniasis in Sanliurfa, Turkey.

As part of a project to study the possible impact of environmental change on health in southeastern Turkey, we evaluated sandfly species diversity, abundance, and habitat associations in an urban area where cutaneous leishmaniasis was undergoing epidemic re-emergence. Houses and caves in and around the city of Sanliurfa, Turkey, were sampled using mechanical aspirators, sticky papers, and CDC light traps. Of 1,649 sandflies captured, including 6 Phlebotomus and 1 Sergentomyia species, nearly all were P. papatasi (Scopoli) (967) or P. sergenti Parrot (674). Sandflies were active during June-September (hot dry season), but not during January (cool rainy season). Resting phlebotomines were abundant inside houses. Houses sampled in 3 neighborhoods with a high cutaneous leishmaniasis incidence (9-65 cases per 1,000 population) had > 10 times more flies than at a comparison site where few cases (0.2 per 1,000) have been reported. Results indicated that P. sergenti or P. papatasi were the probable vectors of cutaneous leishmaniasis during this outbreak and that control of these sandflies may eliminate transmission.

Animals↗
PubMed1998

Tsetse thrombin inhibitor: bloodmeal-induced expression of an anticoagulant in salivary glands and gut tissue of Glossina morsitans morsitans.

The tsetse thrombin inhibitor, a potent and specific low molecular mass (3,530 Da) anticoagulant peptide, was purified previously from salivary gland extracts of Glossina morsitans morsitans (Diptera: Glossinidae). A 303-bp coding sequence corresponding to the inhibitor has now been isolated from a tsetse salivary gland cDNA library by using degenerate oligonucleotide probes. The full-length cDNA contains a 26-bp untranslated segment at its 5' end, followed by a 63-bp sequence corresponding to a putative secretory signal peptide. A 96-bp segment codes for the mature tsetse thrombin inhibitor, whose predicted molecular weight matches that of the purified native protein. Based on its lack of homology to any previously described family of molecules, the tsetse thrombin inhibitor appears to represent a unique class of naturally occurring protease inhibitors. Recombinant tsetse thrombin inhibitor expressed in Escherichia coli and the chemically synthesized peptide are both substantially less active than the purified native protein, suggesting that posttranslational modification(s) may be necessary for optimal inhibitory activity. The tsetse thrombin inhibitor gene, which is present as a single copy in the tsetse genome, is expressed at high levels in salivary glands and midguts of adult tsetse flies, suggesting a possible role for the anticoagulant in both feeding and processing of the bloodmeal.

Amino Acid Sequence↗
PubMed1998

Stability of alpha-amylase immobilized on poly(methyl methacrylate-acrylic acid) microspheres.

Poly(methyl methacrylate-acrylic acid) microspheres were prepared and the acid groups were activated by using either carbodiimide (CDI) or thionyl chloride (SOCl2). alpha-Amylase was covalently bound on these activated microspheres. The properties of the immobilized enzyme were investigated and compared with those of the free enzyme. The relative activities were found to be 80.4 and 67.5% for carbodiimide and thionyl chloride bound enzymes, respectively. Maximum activities were obtained at lower pHs and higher temperatures upon immobilization compared to free enzyme. No change in Vmax and approximately 12-fold increase in K(m) were observed for immobilized enzymes. The enzyme activities, after storage for 1 month, were found to be 24.5 and 52.5% of the initial activity values for CDI and SOCl2 activated matrices, respectively. On the other hand the free enzyme lost its activity completely in 20 days. Immobilization, storage stability and repeated use capability experiments carried out in the presence of Ca2+ ions demonstrated higher stability, such as SOCl2 immobilized enzyme retained 83.7% and CDI immobilized enzyme retained 90.3% of the original activity of the enzyme. The immobilized enzymes that were used 20 times in 3 days in repeated batch experiments demonstrated that, in the absence of Ca2+ ions about 75% and in the presence of Ca2+ ions greater than 90% of the original enzyme activity was retained.

Calcium↗
PubMed1998

Performing testicular or epididymal sperm retrieval prior to the injection of hCG.

PURPOSE: Our purpose was to determine the feasibility and efficacy of performing testicular or epididymal sperm retrieval prior to the injection of human chorionic gonadotropin (hCG). METHODS: This report deals with 87 sperm-positive percutaneous epididymal sperm aspiration (PESA), percutaneous testicular sperm aspiration (PTSA), or testicular sperm extraction (TESE) cycles. All sperm retrieval procedures were performed prior to administration of hCG to the women. Retrieved spermatozoa were cultured in vitro in simple medium for approximately 40 hr prior to intracytoplasmic sperm injection. RESULTS: In all but one cycle in which TESE was performed for nonobstructive azoospermia, motile sperm were available for ICSI. The overall fertilization rate was 53%. Pregnancy rate per transfer and implantation rate per embryo were 41.2 and 15.7%, respectively. CONCLUSIONS: Satisfactory fertilization and pregnancy rates can be achieved when PESA, PTSA, or TESE is performed prior to the injection of hCG followed by in vitro culture of spermatozoa approximately 40 hr before ICSI. Scheduling of testicular or epididymal sperm retrieval cases in this way appears to ease the workload on laboratory and operating room personnel. Furthermore, withholding hCG when sperm is absent may obviate the unnecessary risk of ovarian hyperstimulation when spermatozoa cannot be retrieved.

Biopsy↗
PubMed1998

Oocyte morphology does not affect fertilization rate, embryo quality and implantation rate after intracytoplasmic sperm injection.

In this study, we compared the fertilization rate and embryo quality after intracytoplasmic sperm injection (ICSI) as they relate to oocyte morphology. A total of 654 ICSI cycles yielding 5903 metaphase II oocytes were observed. The oocytes retrieved in these cycles were divided into (i) normal oocytes, (ii) oocytes with extracytoplasmic abnormalities (dark zona pellucida and large perivitelline space), (iii) oocytes with cytoplasmic abnormalities (dark cytoplasm, granular cytoplasm, and refractile body), (iv) oocytes with shape abnormalities, and (v) oocytes with more than one abnormality (double and triple abnormalities). Intracytoplasmic vacuoles and aggregates of smooth endoplasmic reticulum were not recorded separately. The fertilization rate and quality of morphologically graded embryos did not differ between the groups. There were 77 cycles where all transferred embryos were derived from abnormal oocytes, and 164 cycles where all embryos were derived from normal oocytes. These cycles were studied further. The two groups were comparable regarding mean female age, duration of infertility, duration of ovarian stimulation, number of ampoules of gonadotrophin injected, and number of oocytes retrieved. Two clinical pregnancy rates (44.4 versus 42.1%) and implantation rates per embryo (10.3 versus 13.2%) were similar. In conclusion, in couples undergoing ICSI, abnormal oocyte morphology is not associated with a decreased fertilization rate or unfavourable embryo quality. Furthermore, embryos derived from abnormal oocytes yield similar clinical pregnancy and implantation rates when transferred compared with embryos derived from normal oocytes.

Cell Size↗
PubMed1998

Evaluation of uterine cavity by sonohysterography in women scheduled for intracytoplasmic sperm injection.

A prospective study was performed to determine the feasibility of evaluating the uterine cavity by sonohysterography (SHG) in women who were scheduled for intracytoplasmic sperm injection (ICSI) due to severe male factor infertility and who had not had a previous hysterosalpingography (HSG). Sonohysterography was performed in 80 women scheduled for ICSI. A subsequent hysteroscopy was undertaken in patients with intracavitary lesions. The outcome of ICSI for the women undergoing SHG was compared with that of 240 cycles performed (during the same time period) in patients who had a normal HSG before admission to the clinic. There were no complications attributable to the SHG procedure. Hysteroscopy correctly identified all lesions depicted by SHG. SHG and HSG groups were comparable with regard to female age and duration of infertility. Clinical pregnancy rates per transfer were 40.2% and 42.5% in the SHG and HSG groups, respectively. Abortion rates in the two groups were also similar (14.8 and 11.0%, respectively). In conclusion, sonohysterography appears to be a simple, inexpensive, and safe alternative to HSG for evaluation of the uterine cavity in women scheduled for ICSI.

Female↗
PubMed1998

Progression of excess embryos to the blastocyst stage predicts pregnancy and implantation rates after intracytoplasmic sperm injection.

Excess embryos from patients undergoing intracytoplasmic sperm injection and embryo transfer for male infertility were cultured to determine the rate and timing of their progression to the blastocyst stage. In 194 embryo transfer cycles, four embryos with the morphologically best grading were transferred and at least two embryos were cultured. The cycles were classified as: group 1: no excess embryos reached blastocyst stage, group 2: >50% of embryos reached blastocyst stage by days 4-5, group 3: <50% of embryos reached the blastocyst stage by days 4-5, group 4: >50% of the embryos reached blastocyst stage by days 6-7, group 5: <50% of the embryos reached blastocyst stage by days 6-7. All groups were similar regarding female age, duration of infertility, and parameters of ovarian stimulation. In group 1, clinical pregnancy and implantation rates were 14 and 11% respectively, and were similar to those of group 4. In group 2, clinical pregnancy and implantation rates were 75 and 33%. Multiple implantations occurred in 81% of group 2 or 3 cycles, compared to none in group 1 cycles. The results suggest that the development potential of the embryo is intrinsic, and that embryos which carry a high potential for development yield a high clinical pregnancy rate and multiple implantations.

Adult↗
PubMed1997

Prevention of insect-borne disease: an approach using transgenic symbiotic bacteria.

Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting insects may serve as a powerful approach to control certain arthropod-borne diseases. The endosymbiont of the Chagas disease vector, Rhodnius prolixus, has been transformed to express cecropin A, a peptide lethal to the parasite, Trypanosoma cruzi. In insects carrying the transformed bacteria, cecropin A expression results in elimination or reduction in number of T. cruzi. A method has been devised to spread the transgenic bacteria to populations of R. prolixus, in a manner that mimics their natural coprophagous route of symbiont acquisition.

Animals↗
PubMed1997

Platysma myocutaneous flap: use for intraoral reconstruction.

Twenty patients were treated for intraoral epidermoid carcinoma with a single-stage reconstructive technique using a myocutaneous flap based on the platysma muscle. This flap carries on its distal tip a portion of isolated cervical skin to be used for intraoral replacement of the resected tissue. The superior vascular pedicle, the submental branch of the facial artery, was used. The platysma skin flap will survive if the blood supply from at least one region is preserved. In addition, it may be beneficial to include the external jugular and/or the communicating veins in the flap. Only three minor complications were seen and healed spontaneously. The flap has proved to be highly reliable and has significant benefits over many other techniques commonly used for head and neck reconstruction.

Adult↗
PubMed1997

Phylogenetic characterization of two transovarially transmitted endosymbionts of the bedbug Cimex lectularius (Heteroptera:Cimicidae).

Two different inherited bacterial symbionts from ovary tissue of the bedbug Cimex lectularius were characterized by gene amplification and sequencing analysis of their 16S rDNA gene. The first bacterium belongs to the Wolbachia subgroup of the alpha-Proteobacteria, the second is a member of the gamma-subdivision, and is closely related to the bacterial parasite of the leafhopper Euscelidius variegatus (BEV) which was shown to be capable of transovarial transmission. The high similarity (> 97%) between the C. lectularius symbiont and BEV indicates that these two microorganisms belong to the same lineage and share the ability to invade distant insect hosts to fulfill their symbiotic functions and to establish transovarial transmission to future generations.

Animals↗
PubMed1997

Evaluation of intrauterine abnormalities in infertile patients by sonohysterography.

The purpose of this study was to assess the usefulness of sonohysterography in the detection of abnormalities of the uterine cavity in infertile patients, compared with other diagnostic methods. Transvaginal ultrasonography, sonohysterography, hysterosalpingography and finally hysteroscopy were performed in 37 patients with primary and 25 patients with secondary infertility. Suspected uterine anomalies were also confirmed by laparoscopy. Transvaginal ultrasonography and hysterosalpingography were able to detect 36.3 and 72.7% of uterine pathologies respectively. Sonohysterography was able to detect all the anomalies except for a single endometrial polyp (90.3%). However, there was no significant difference between the diagnostic capabilities of these methods. We recommend the use of sonohysterography as an easy, cheap and noninvasive method for the diagnosis of intrauterine pathologies in infertile patients.

Adult↗
PubMed1997

Phylogeny and potential transmission routes of midgut-associated endosymbionts of tsetse (Diptera:Glossinidae).

Many tsetse species (Diptera: Glossinidae) harbour two morphologically different intracellular endosymbiotic microorganisms associated with gut tissue: primary (P) and secondary (S) endosymbionts. The P-endosymbionts of tsetse (Wigglesworthia glossinidia) are sequestered in specialized epithelial cells, bacteriocytes, which form a structure (bacteriome) in the anterior portion of the gut. Phylogenetic characterization of P-endsymbionts from the three subgenera of genus Glossina has shown that these organisms constitute a distinct lineage within the gamma-subdivision of Proteobacteria and have evolved concordantly with their insect host species, suggesting an evolutionarily ancient association for this symbiosis. The S-endosymbiont is a smaller (1-2 micron) gram-negative rod and is harboured in midgut epithelial cells. Its phylogenetic characterization from Glossina morsitans morsitans had shown that it is a member of the family Enterobacteriaceae within the gamma-3 subdivision of the Proteobacteria, closely related to enteric bacteria. Some tsetse species harbour a third bacterium in their reproductive tissue, which was shown phylogenetically to belong to to the Wolbachia pipientis assemblage of microorganisms. Here, we show that S-endosymbionts from five tsetse species, representing all three subgenera, form a cluster of closely related microorganisms, based on their almost identical 16S rRNA gene sequences. The high similarity provides strong evidence of recent independent acquisition of S-endosymbionts by individual tsetse species, unlike Wigglesworthia which displays concordant evolution with host insect species. A PCR-based assay and restriction fragment length polymorphism (RFLP) analysis was developed to localize the S-endosymbionts and Wigglesworthia in ovary, egg, milk-gland and spermatheca tissues in order to investigate the potential routes for the vertical transmission of these symbionts to the intrauterine larvae. Only S-endosymbionts were found to infect milk gland tissue, suggesting that milk gland secretions represent a route of transmission for these symbionts into the developing larva. The ovary tissue was found to harbour only Wolbachia, confirming its transovarial transmission, whereas the mode of transmission of Wigglesworthia remains unknown.

Animals↗
PubMed1997

Audiological findings in kernicteric patients.

Audiological findings in kernicteric patients. Thirty patients followed up because of kernicterus sequelae and 15 normal children serving as control group were examined to determine their hearing status and evoked response audiometry (ERA) results. Seventeen out of the 30 patients (57%) had high frequency sensorineural hearing loss. Sixteen of them had bilateral hearing loss. Ten had no response or prolonged bilateral latencies. The results showed that high neonatal serum bilirubin levels affect the hearing adversely.

Adolescent↗