36 research outputs found
Co-culture of cryopreserved healthy sertoli cells with testicular tissue of non-obstructive azoospermia (NOA) patients in culture media containing follicle-stimulating hormone (FSH)/testosterone has no advantage in germ cell maturation
Different cell culture conditions and techniques have been used to mature spermatogenic cells to increase the success of in vitro fertilization. Sertoli cells (SCs) are essential in maintaining spermatogenesis and FSH stimulation exerts its effect through direct or indirect actions on SCs. The effectiveness of FSH and testosterone added to the co-culture has been demonstrated in other studies to provide microenvironment conditions of the testicular niche and to contribute to the maturation and meiotic progression of spermatogonial stem cells (SSCs). In the present study, we investigated whether co-culture of healthy SCs with the patient's testicular tissue in the medium supplemented with FSH/testosterone provides an advantage in the differentiation and maturation of germ cells in NOA cases (N = 34). In men with obstructive azoospermia (N = 12), healthy SCs from testicular biopsies were identified and purified, then cryopreserved. The characterization of healthy SCs was done by flow cytometry (FC) and immunohistochemistry using antibodies specific for GATA4 and vimentin. FITC-conjugated annexin V/PI staining and the MTT assay were performed to compare the viability and proliferation of SCs before and after freezing. In annexin V staining, no difference was found in percentages of live and apoptotic SCs, and MTT showed that cryopreservation did not inhibit SC proliferation compared to the pre-freezing state. Then, tissue samples from NOA patients were processed in two separate environments containing FSH/testosterone and FSH/testosterone plus co-culture with thawed healthy SCs for 7 days. FC was used to measure 7th-day levels of specific markers expressed in spermatogonia (VASA), meiotic cells (CREM), and post-meiotic cells (protamine-2 and acrosin). VASA and acrosin basal levels were found to be lower in infertile patients compared to the OA group (8.2% vs. 30.6% and 12.8% vs. 30.5%, respectively; p < 0.05). Compared to pre-treatment measurements, on the 7th day in the FSH/testosterone environment, CREM levels increased by 58.8% and acrosin levels increased by 195.5% (p < 0.05). Similarly, in medium co-culture with healthy SCs, by day 7, CREM and acrosin levels increased to 92.2% and 204.8%, respectively (p < 0.05). Although VASA and protamine levels increased in both groups, they did not reach a significant level. No significant difference was found between the day 7 increase rates of CREM, VASA, acrosin and protamine-2 in either FSH/testosterone-containing medium or in medium additionally co-cultured with healthy SCs (58.8% vs. 92.2%, 120.6% vs. 79.4%, 195.5% vs. 204.8%, and 232.3% vs. 198.4%, respectively; p > 0.05). Our results suggest that the presence of the patient's own SCs for maturation of germ cells in the culture medium supplemented with FSH and testosterone is sufficient, and co-culture with healthy SCs does not have an additional advantage. In addition, the freezing-thawing process would not impair the viability and proliferation of SCs.</p
Clinical biochemistry laboratory rejection rates due to various types of preanalytical errors
Introduction: Preanalytical errors, along the process from the beginning of test requests to the admissions of the specimens to the laboratory, cause the rejection of samples. The aim of this study was to better explain the reasons of rejected samples, regarding to their rates in certain test groups in our laboratory.
Materials and methods: This preliminary study was designed on the rejected samples in one-year period, based on the rates and types of inappropriateness. Test requests and blood samples of clinical chemistry, immunoassay, hematology, glycated hemoglobin, coagulation and erythrocyte sedimentation rate test units were evaluated. Types of inappropriateness were evaluated as follows: improperly labelled samples, hemolysed, clotted specimen, insufficient volume of specimen and total request errors.
Results: A total of 5,183,582 test requests from 1,035,743 blood collection tubes were considered. The total rejection rate was 0.65 %. The rejection rate of coagulation group was significantly higher (2.28%) than the other test groups (P < 0.001) including insufficient volume of specimen error rate as 1.38%. Rejection rates of hemolysis, clotted specimen and insufficient volume of sample error were found to be 8%, 24% and 34%, respectively. Total request errors, particularly, for unintelligible requests were 32% of the total for inpatients.
Conclusions: The errors were especially attributable to unintelligible requests of inappropriate test requests, improperly labelled samples for inpatients and blood drawing errors especially due to insufficient volume of specimens in a coagulation test group. Further studies should be performed after corrective and preventive actions to detect a possible decrease in rejecting sample
DOWNREGULATION OF STEAROYL-COA DESATURASE 1 (SCD-1) PROMOTES RESISTANCE TO IMATINIB IN CHRONIC MYELOID LEUKEMIA
Chronic myeloid leukemia (CML) is a malignant hematopoietic stem cell disease resulting in the fusion of BCR and ABL genes and characterized by the presence of the reciprocal translocation t(9;22)(q34;q11). BCR-ABL, a product of the BCR-ABL fusion gene, is a structurally active tyrosine kinase and plays an important role in CML disease pathogenesis. Imatinib mesylate (IMA) is a strong and selective BCR-ABL tyrosine kinase inhibitor. Although IMA therapy is an effective treatment, patients may develop resistance to IMA therapy over time. This study investigated the possible genetic resistance mechanisms in patients developing resistance to IMA. We did DNA sequencing in order to detect BCR-ABL mutations, which are responsible for IMA resistance. Moreover, we analyzed the mRNA expression levels of genes responsible for apoptosis, such as BCL-2, P53, and other genes (SCD-1, PTEN). In a group of CML patients resistant to IMA, when compared with IMA-sensitive CML patients, a decrease in SCD-1 gene expression levels and an increase in BCL-2 gene expression levels was observed. In this case, the SCD-1 gene was thought to act as a tumor suppressor. The present study aimed to investigate the mechanisms involved in IMA resistance in CML patients and determine new targets that can be beneficial in choosing the effective treatment. Finally, the study suggests that the SCD-1 and BCL-2 genes may be mechanisms responsible for resistance.
Keywords CML; Imatinib resistance; BCR-ABL mutations; SCD-
IL-6 mediated JAK/STAT3 signaling pathway in cancer patients with cachexia
CONCLUSION: STAT3 may be considered as a therapeutic target for cachectic patients with gastric, lung and breast cancer. Furthermore, IL-6 mediates STAT3 activation in cachectic gastric and breast cancer patients (Tab. 5, Fig. 2, Ref. 62)
A Cost Model for Path Expressions in Object-Oriented Queries
Query processing remains one of the important challenges of Object-Oriented Database Management Systems. Cost based query optimization involves creating alternative executing plans for a given query and executing the least costly one within a cost model framework. In Object-Oriented Database Management Systems (OODBMSs) objects may store references to other objects (precomputed joins), and path expressions are used in query languages. Although the cost fomulas for explicit joins and the selectivities of attributes and joins are well-known in the relational model, there is no similar work involving path expressions for OODBMSs. However in order to optimize object-oriented queries involving path expressions, a cost model is essential. This information is necessary for deciding whether to use pointer chasing or to convert the path expressions into explicit joins and also for deciding the execution order of path expressions. In this paper, we provide a cost model that includes the formulas..
A heuristic approach for optimization of path expressions
Abstract. The object-oriented database management systems store references to objects (implicit joins, precomputed joins), and use path expressions in query languages. One way of executing path expressions is pointer chasing of precomputed joins. However it has been previously shown that converting implicit joins to explicit joins during the optimization phase may yield better execution plans. A path expression is a linear query, therefore, considering all possible join sequences within a path expression is polynomial in the number of classes involved. Yet, when the implicit joins are converted to explicit joins in a query involving multiple path expressions bound to the same bind variable, the query becomes a star query and thus considering all possible joins is exponential in the numberofpathsinvolved. This implies that there is a need for improvement by using heuristic in optimizing queries involving multiple path expressions. A heuristic based approach for optimizing queries involving multiple path expressions is described in this paper. First, given the cost and the selectivities of path expressions by considering a path expression as a unit of processing, we provide an algorithm that gives the optimum execution order of multiple path expressions bound to the same bind variable. For this purpose, we derive the formulas for the selectivities of path expressions. Then by using this ordering as a basis we provide a general heuristic approach for optimizing queries involving multiple path expressions. Two optimizers are developed to compare the performance of the heuristic based approach suggested in this paper with the performance of an optimizer based on an exhaustive search strategy. The exhaustive optimizer is generated through Volcano Optimizer Generator (VOG). The results of the experiments indicate that the heuristic based optimizer has a superior performance with the increasing number of path expressions.
Intragastric alendronate therapy in two infants with vitamin D intoxication: A new method
In recent years, alendronate, an oral biphosphonate, has been added to therapy of hypercalcemia secondary to vitamin D intoxication in children. Alendronate may cause mucosal ulcerations in the mouth and esophagus. We report our experience in two infants with vitamin D intoxication to whom alendronate therapy was administered through nasogastric tube, an alternate route for alendronate administration
Abstract A Cost Model for Path Expressions in Object-Oriented Queries
Query processing remains one of the important challenges of Object-Oriented Database Management Systems. Cost based query optimization involves creating alternative executing plans for a given query and executing the least costly one within a cost model framework. In Object-Oriented Database Management Systems (OODBMSs) objects may store references to other objects (precomputed joins), and path expressions are used in query languages. Although the cost fomulas for explicit joins and the selectivities of attributes and joins are well-known in the relational model, there is no similar work involving path expressions for OODBMSs. However in order to optimize object-oriented queries involving path expressions, a cost model is essential. This information is necessary for deciding whether to use pointer chasing or to convert the path expressions into explicit joins and also for deciding the execution order of path expressions. In this paper, we provide a cost model that includes the formulas for the costs and selectivities of forward and backward path traversals. 1
Implementation Aspects of an Object-Oriented DBMS
1 Introduction This paper describes the design and implementation of an OODBMS, namely the METU Object-Oriented DBMS (MOOD). MOOD [Dog 94b] is developed on the Exodus Storage Manager (ESM) [ESM 92] and therefore some of the kernel functions like storage management, concurrency control, backup and recovery of data were readily available through ESM. In addition ESM has a client-server architecture and each MOOD process is a client application in ESM. The kernel functions provided by MOOD are the optimization and interpretation of SQL statements, dynamic linking of functions, and catalog management. SQL statements are interpreted whereas functions (which have been previously compiled with C ) within SQL statements are dynamically linked and executed. A query optimizer is implemented by using the Volcano Query Optimizer Generator. A graphical user interface, namely MoodView [Arp 93a, Arp 93b], is developed using Motif. MoodView displays both the schema information and the query results ..
Design and Implementation of an Object-Oriented SQL Query Processor with an Optimizer
A SQL-like object-oriented query language is implemented on Exodus Storage Manager with an original query optimization strategy based on the object-oriented features of the language. For this purpose the selectivity of a path expression, cost of forward and backward traversals are calculated, and join sizes are estimated. An original strategy is developed for choosing the order of selections and path traversals. The optimization algorithm is designed in such a way that it generates the query execution plan in one pass. This is accomplished through combining the information collected during parsing with the cost estimations. In other words, the algebraic manipulations and transformations are performed by considering the effect of the cost analysis on them. It is clear that in this way the query rewriting becomes more intelligent since the algebraic transformations are performed with apriori information on how well they will perform. 1. Introduction As a part of the MOODS (METU Object-..