Schistosoma mansoni and Host-Parasite Interactions

__Abstract__ Blood-dwelling parasitic trematodes (flatworms) of the genus Schistosoma cause the disease schistosomiasis or Bilharzia. There are 5 different Schistosoma species that infect humans and many other infecting different mammals. Over 200 million people worldwide are infected with schistosomes, mainly of the species S. haematobium, S. mansoni and S. japonicum. The disease is endemic in tropical areas and endemicity is dependent on the presence of the intermediate host, an aquatic snail, in fresh surface water. There is a strong variation in epidemiology between regions and localities, depending on local determinants such as irrigation or draining canals and human sanitary conditions

The Learning Curve for Flank Percutaneous Nephrolithotomy for Kidney Calculi: A Single Surgeon's Experience

PURPOSE: Percutaneous nephrolithotomy (PCNL) is conventionally conducted in the prone position. However, the prone position increases anesthesia-related morbidity and position changes lengthen the operation time. We report perioperative outcomes and the learning curve for flank PCNL on the basis of a single surgeon's experience. MATERIALS AND METHODS: This study investigated 53 cases of flank PCNL performed for renal stones at our institution from April 2008 to September 2010. We compared mean operative time, stone-free rate, drop in hemoglobin level, length of hospital stay, complications, and need for additional procedures after the surgery. The 53 cases were divided into three groups by case number to compare therapeutic effect, stability, and the learning curve for flank position PCNL. RESULTS: The mean operation time for the 53 patients was 97.3+/-43.1 minutes. The mean operation time gradually decreased as the surgeon accumulated experience. From the 36th case, the mean operation time showed a statistically significant decrease to 72.2+/-24.1 minutes (p=0.003). The overall stone-free rate was 64.2% for all procedures (range, 61.1-76.5%). There were no significant differences in the drop in hemoglobin level, stone-free rate, re-treatment, hospital stay, or complication rate. There was no injury to the bowel or renal vessels, and no other major complications occurred. CONCLUSIONS: Flank PCNL can be used to remove renal stones effectively while overcoming the disadvantages of the existing prone position PCNL. After 36 cases, the learning curve showed acquisition of surgical competence. The clinical experience reported here suggests that flank PCNL is a safe and feasible technique.ope

Schistosoma mansoni: The egg, biosynthesis of the shell and interaction with the host

The schistosome eggshell is a hardened and tanned structure made from cross-linked proteins. It is synthesized within the female worm from many different kinds of proteins and glycoproteins. Once the egg is released in the circulation, the outer surface of the eggshell is exposed and hence a direct site of interaction between the parasite and the host. The major eggshell protein is p14, but about one third of the eggshell is made from common cellular proteins, some of which are known to be immunogenic. This has many consequences for parasite-host interactions. However, so far, the eggshell has gained little attention from researchers. We will discuss the structure of the eggshell and its role in granuloma formation, host factor binding and egg excretion. (c) 2011 Elsevier Inc. All rights reserved

The tegumental surface membranes of Schistosoma mansoni are enriched in parasite-specific phospholipid species

The complex surface structure of adult Schistosoma mansoni, the tegument, is essential for survival of the parasite. This tegument is syncytial and is covered by two closely-apposed lipid bilayers that form the interactive surface with the host. In order to identify parasite-specific phospholipids present in the tegument, the species compositions of the major glycerophospholipid classes, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine and phosphatidylinositol, including lysophospholipid species, were analysed in adult S. mansoni worms, isolated tegumental membranes and hamster blood cells. It was shown that there are large differences in species composition in all four phospholipid classes between the membranes of S. mansoni and those of the host blood cells. The species compositions of phosphatidylserine and phosphatidylcholine were strikingly different in the tegument compared with the whole worm. The tegumental membranes are especially enriched in lysophospholipids, predominantly eicosenoic acid (20:1)-containing lyso-phosphatidylserine and lyso-phosphatidylethanolamine species. Furthermore, the tegument was strongly enriched in phosphatidylcholine that contained 5-octadecenoic acid, an unusual fatty acid that is not present in the host. As we have shown previously that lysophospholipids from schistosomes affect the parasite-host interaction, excretion of these tegument-specific phospholipid species was examined in vitro and in vivo. Our experiments demonstrated that these lysophospholipids are not significantly secreted during in vitro incubations and are not detectable in peripheral blood of infected hosts. However, these analyses demonstrated a substantial decrease in PI content of blood plasma from schistosome-infected hamsters, which might indicate that schistosomes influence exosome formation by the host. (C) 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved

Functional results after surgical treatment for congenital knee dislocation

BACKGROUND: Congenital knee dislocation (CDK) is a rare congenital deformity, which often requires surgery for treatment. Little objective data exist characterizing the outcome of patients who require operative treatment for this condition. The purposes of this study were to objectively evaluate the functional, clinical, and gait outcomes of patients who underwent surgical treatment of CDK; and compare the results of outcome between 2 surgical approaches for this condition: quadricepsplasty and femoral shortening. METHODS: We performed a retrospective review of all patients (7) treated surgically for CDK. Patients were evaluated at an average follow-up of 12+6 years. Each patient underwent a clinical examination, functional evaluation using the Lysholm Knee Questionnaire and Pediatric Outcomes Data Collection Instrument, and a 3-dimensional gait evaluation. The results of the total group were compared with normal controls. Additionally, results of the patients treated with quadricepsplasty were compared with patients treated with femoral shortening. RESULTS: Total knee range of motion for the entire group averaged 112 degrees, with 8 of the 9 knees having flexion\u3e90 degrees. Seven of the 9 knees were found to have some degree of instability on examination, yet none of the patients reported using any form of brace for ambulation. Functional evaluation showed good knee specific and overall function, comparable to normal controls. There were no differences in clinical or functional outcomes between the 2 surgical approaches. Gait analysis revealed a stiff-knee gait pattern to the congenital knee dislocation group, as compared with normal controls, and subtle differences in knee function between the surgical approaches. CONCLUSIONS: The function of patients after surgical treatment for CDK seems to be quite good compared with normal controls. Good knee specific and overall function scores are reported with limitations seen only in higher demand activities. Despite instability of the knee noticed on clinical examination, patients ambulate without braces and have a functional knee range of motion. Little difference in outcome was seen between the 2 surgical approaches used to treat this condition. LEVEL OF EVIDENCE: Therapeutic Study, Level III. Copyright © 2010 by Lippincott Williams & Wilkins