Biomechanical characteristics of human fetal membranes. Preterm fetal membranes are stronger than term fetal membranes

The purpose of this study was to determine the biomechanical characteristics of human fetal membranes (FM) throughout gestation. Biomechanical properties were determined for 115 FM of 23-41 weeks gestation using our previously described methodology. The areas of membrane immediately adjacent to the strongest and weakest tested spots were sampled for histomorphometric analysis. Clinical data on the patients whose FM were examined were also collected. FM less than 28 weeks gestation were associated with higher incidence of abruption and chorioamnionitis. Topographically FM at all gestations had heterogeneous biomechanical characteristics over their surfaces with distinct weak areas. The most premature membranes were the strongest. FM strength represented by rupture force and work to rupture decreased with increasing gestation in both weak and strong regions of FM. This decrease in FM strength was most dramatic at more than 38 weeks gestation. The FM component amnion-chorion sublayers were thinner in the weak areas compared to strong areas. Compared to term FM, preterm FM are stronger but have similar heterogeneous weak and strong areas. Following a gradual increase in FM weakness with increasing gestation, there is a major drop-off at term 38 weeks gestation. The FM weak areas are thinner than the stronger areas. Whether the difference in thickness is enough to account for the strength differences is unknown.     

Development of a loop-mediated isothermal amplification method for detection of Theileria lestoquardi

A loop-mediated isothermal amplification (LAMP) assay was developed for the diagnosis of Theileria lestoquardi infection. The primers were designed based on the clone-5 sequence of T. lestoquardi. The specificity and sensitivity of the assay were established. Analysis of the specificity showed that the selected LAMP primers amplified the target sequence from T. lestoquardi DNA successfully, while no amplification was seen with DNA from Theileria annulata, Theileria ovis, Babesia ovis, Anaplasma ovis, or ovine genomic DNA. The specificity of the LAMP product was further confirmed by restriction digestion and sequencing. The sensitivity of the LAMP assay was analyzed in comparison to PCR resulting in a detection limit of 10 fg/μl of plasmid DNA containing the clone-5 sequence. The suitability for utilizing the LAMP assay in the field for the diagnosis of T. lestoquardi infection was tested on 100 field samples collected in Sudan and compared with results obtained by PCR. The relative specificity and sensitivity of the established LAMP assay was determined to be 92.1% and 87.5%, respectively, indicating that it may be regarded as an alternative molecular diagnostic tool to PCR which could be used for epidemiological surveys on T. lestoquardi infection.     

Rigid ureteroscopy for ureteral stones: factors associated with intraoperative adverse events

PURPOSE: To analyze some of the factors that may be associated with a higher incidence of complications during management of ureteral stones by rigid ureteroscopy. PATIENTS AND METHODS: We reviewed all ureteroscopic interventions aimed at stone extraction and/or fragmentation in our institution from 2001 through 2005. A total of 442 interventions were eligible for inclusion. Our focus was concentrated on (1) patient characteristics (age, gender, duration of symptoms, history of urinary schistosomiasis, and history of surgery involving the affected ureter), (2) stone characteristics (number, length, width, and level of the ureter affected), (3) the affected reno-ureteral unit (which side was affected, the kidney's ability to excrete contrast medium, and the status of the ureter proximal and distal to the stone), and finally (4) experience level of the surgeon in charge (junior v senior). The occurrence of intraoperative adverse events was considered a dependent variable and was statistically related to each of the above factors as independent variables. RESULTS: Intraoperative adverse events were encountered in 121 interventions including stone migration in 54, minor mucosal injuries in 24, ureteral perforation in 12, ureteral avulsion in 2, and aborted procedure due to bleeding or edema in 29. Symptomatology present for more than 3 months, a negative history of schistosomiasis, a positive history of ureteral surgery, stones above the ischial spines, stones >5 mm in width, a dilated proximal ureter, kidneys that failed to excrete contrast medium, and involvement of a more junior urologist were factors that were associated with a statistically significantly higher incidence of intraoperative complications. CONCLUSIONS: Rigid ureteroscopic stone manipulation remains a procedure that should be handled cautiously. Existence of any of the above risk factors should alert urologists, particularly at training centers, to adopt all possible precautionary measures.