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A Karabay

Publications and source records attributed to A Karabay.

9 recordsLinked to original sources
PubMed2003

Identification of Ncd tail domain-binding sites on the tubulin dimer.

The Drosophila non-claret disjunctional (Ncd) kinesin-like protein is required for spindle assembly in oocytes and spindle maintenance in early embryos. Through the action of ATP-dependent microtubule (MT)-binding sites in the head and ATP-independent MT-binding sites in the tail, Ncd may bundle and, perhaps, slide MTs relative to each other. Our previous work on the MT-binding site of the Ncd tail domain demonstrated that this site, like the MT-binding sites of tau, contains basic residues flanked by proline residues and can promote MT assembly and stability. Here, we characterize the interactions of a monomeric Ncd tail protein with subtilisin-digested MTs in order to identify sites on the tubulin dimer that interact with the Ncd tail. The results provide evidence for four such binding sites per tubulin dimer and support the hypothesis that each binding site consists of a cluster of acidic residues in the C-terminal regions of alpha- and beta-tubulin.

Animals↗
PubMed1999

The Ncd tail domain promotes microtubule assembly and stability.

Non-claret disjunctional (Ncd) is a Drosophila kinesin-like motor required for spindle assembly and maintenance in oocytes and early embryos. Ncd has an ATP-independent microtubule binding site in the N-terminal tail domain as well as an ATP-dependent microtubule binding site in the C-terminal motor domain. The Ncd tail domain shares many properties with the microtubule-associated proteins that regulate microtubule assembly, including microtubule binding and bundling activity and an abundance of basic and proline residues. Given these similarities, we examined the ability of Ncd tail domain proteins to promote MT assembly and stability. The results indicate that the Ncd tail domain can promote MT assembly and stabilize MTs against conditions that induce MT disassembly, and suggest that Ncd may influence MT dynamics within the spindle.

Animals↗
PubMed1999

Identification of microtubule binding sites in the Ncd tail domain.

Nonclaret disjunctional (Ncd) is a minus end-directed, C-terminal motor protein that is required for spindle assembly and maintenance during meiosis and early mitosis in Drosophila oocytes and early embryos. Ncd has an ATP-independent MT binding site in the N-terminal tail domain, and an ATP-dependent MT binding site in the C-terminal motor domain. The ability of Ncd to cross-link MTs through the action of these binding sites may be important for Ncd function in vivo. To identify the region(s) responsible for ATP-independent MT interactions of Ncd, 12 cDNAs coding various regions of Ncd tail domain were expressed in E. coli as C-terminal fusions to thioredoxin (Trx). Ncd tail fusion proteins (TrxNT) were purified by ion exchange (S-Sepharose) and/or Talon metal affinity chromatography. Purified TrxNT and NT proteins were analyzed in microtubule (MT) cosedimentation and bundling assays to identify which tail proteins were able to bind and bundle MTs. Based on the results of these experiments, all TrxNT and NT proteins that showed MT binding activity also bundled MTs, and there are two ATP-independent MT interaction sites in the tail region: one within amino acids 83-100 that exhibits conformation-independent, high-affinity MT binding activity; and another within amino acids 115-187 that exhibits conformation-dependent, lower affinity MT binding activity. It is possible that both of these MT interacting sites combine in the native protein to form a single MT binding site that allows the Ncd tail to bind cargo MTs in vivo.

Adenosine Triphosphate↗
PubMedDate not supplied

Intravenous immunoglobulin for prophylaxis of nosocomial sepsis.

A total of 76 premature newborn infants with gestational age of 34 weeks or less were enrolled in a randomized controlled study to determine whether intravenously administrated immunoglobulin (IVIG) is able to prevent nosocomial sepsis. Forty infants were given 0.5 g/kg IVIG on the first day of life and 36 infants with similar gestational age and birth weight were selected as controls and did not receive IVIG. The frequency of proven sepsis, with a positive blood and/or cerebrospinal fluid culture, was significantly lower in infants who received IVIG as compared to controls (42.5 vs 80.0%) (p < 0.01). The mortality rate attributable to infection was not different in IVIG recipients and in controls (41 vs 48%) (p > 0.05). The overall mortality rates in the two groups were not different either (35.0 vs 44.4%) (p > 0.05). The majority of micro-organisms isolated from the blood culture of the patients were gram negative microorganisms (Klebsiella, Enterobacter). IVIG therapy was believed to be effective for prophylaxis of nosocomial infection, but such therapy was not able to reduce overall mortality rate or mortality rate due to systemic infection in prematurely born infants in our intensive care unit where the causative pathogens are usually gram negative microorganisms.

Cross Infection↗
PubMedDate not supplied

Peritoneal tuberculosis with pelvic abdominal mass, ascites and elevated CA 125 mimicking advanced ovarian carcinoma: a series of 10 cases.

Ten patients with peritoneal tuberculosis who were operated on for suspected advanced ovarian cancer during a 5-year period were analyzed. These 10 cases constituted 1.4% of the 728 new gynecologic cancer cases diagnosed and treated at our department during the same time period. Data were obtained from patients' files and pathology reports. The mean age of cases was 40.6 +/- 6.1 (median 37; range 18-72). Ascites was present together with ill-defined nodularities or thickening in the Douglas pouch and/or in the adnexal areas on pelvic examination in all patients but three, who presented with well-demarcated adnexal masses of about 5 cm in diameter. All patients had elevated serum CA 125 levels with a median of 331 U/ml, (40-560 U/ml). Ultrasound and abdominopelvic CT examinations revealed omental and mesenteric thickening in addition to ascites in all patients, cystic ovarian masses or ovarian enlargement in five, and peritoneal implants in two. Abdominal paracentesis performed in the six cases in whom the findings were felt to be most inconclusive for the diagnosis of ovarian cancer revealed clear exudative fluid with benign cells. Mycobacteria could not be demonstrated on direct preparations. Tuberculosis was diagnosed at laparotomy in all. Patients received antituberculous therapy and serum CA 125 levels returned to normal within 2 months after the beginning of treatment. This case series demonstrates a high rate of misdiagnosis between advanced ovarian cancer and peritoneal tuberculosis. Whereas abdominal paracentesis is useless in ruling out peritoneal tuberculosis, and serum CA 125 levels are not helpful in the differential diagnosis, the latter marker may be useful in the follow-up of patients.

Adolescent↗