Characterization of a UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase with an unusual lectin domain from the platyhelminth parasite Echinococcus granulosus.
(1/170)
As part of a general project aimed at elucidating the initiation of mucin-type O-glycosylation in helminth parasites, we have characterized a novel ppGalNAc-T (UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase) from the cestode Echinococcus granulosus (Eg-ppGalNAc-T1). A full-length cDNA was isolated from a library of the tissue-dwelling larval stage of the parasite, and found to code for a 654-amino-acid protein containing all the structural features of ppGalNAc-Ts. Functional characterization of a recombinant protein lacking the transmembrane domain showed maximal activity at 28 degrees C, in the range 6.5-7.5 pH units and in the presence of Cu2+. In addition, it transferred GalNAc to a broad range of substrate peptides, derived from human mucins and O-glycosylated parasite proteins, including acceptors containing only serine or only threonine residues. Interestingly, the C-terminal region of Eg-ppGalNAc-T1 bears a highly unusual lectin domain, considerably longer than the one from other members of the family, and including only one of the three ricin B repeats generally present in ppGalNAc-Ts. Furthermore, a search for conserved domains within the protein C-terminus identified a fragment showing similarity to a recently defined domain, specialized in the binding of organic phosphates (CYTH). The role of the lectin domain in the determination of the substrate specificity of these enzymes suggests that Eg-ppGalNAc-T1 would be involved in the glycosylation of a special type of substrate. Analysis of the tissue distribution by in situ hybridization and immunohistochemistry revealed that this transferase is expressed in the hydatid cyst wall and the subtegumental region of larval worms. Therefore it could participate in the biosynthesis of O-glycosylated parasite proteins exposed at the interface between E. granulosus and its hosts. (+info)
Short report: the use of a polymerase chain reaction to detect Echinococcus granulosus (G1 strain) eggs in soil samples.
(2/170)
Cystic echinococcosis is a re-emerging disease in central Asia. A total of 120 soil samples taken from 30 gardens of rural homesteads in southern Kazakhstan were analyzed for the presence of taeniid eggs using a concentration technique. Of these, 21 (17.5%) were shown to be contaminated with taeniid eggs. These isolated taeniid eggs were further analyzed using a polymerase chain reaction specific for the G1 (sheep) strain of the tapeworm Echinococcus granulosus, and five samples were shown to be positive. This study demonstrates the widespread contamination of the environment with E. granulosus eggs in an Echinococcus-endemic area and thus the potential for indirect transmission of E. granulosus to humans from such sources. (+info)
Usefulness of PCR analysis for diagnosis of alveolar echinococcosis with unusual localizations: two case studies.
(3/170)
The report presents two cases where diagnosis of alveolar echinococcosis was confirmed by Echinococcus multilocularis and Echinococcus granulosus PCR. The extrahepatic osseous involvement and the absence of initial hepatic involvement are unusual in both cases. Due to limitations of serological interpretation, PCR was useful to diagnose atypical echinococcosis. (+info)
Clinics in diagnostic imaging (102).
(4/170)
A 19-year-old man presented with cough and haemoptysis of ten days duration. He also had mild right hypochondrial pain. Chest radiograph and computed tomography (CT) showed a rounded soft tissue density opacity with an air crescent sign. CT showed multiple cystic lesions in the liver with a daughter cyst in its lateral wall. Diagnosis of hydatid disease of lung and liver was made. The contents of the liver cyst were aspirated, hypertonic saline instilled, re-aspirated, and absolute alcohol injected. Hydatid disease is endemic in certain parts of the world. Although the lungs and liver are most frequently affected, the disease can arise in any part of the body and should be kept in differential diagnosis whenever a cystic lesion is encountered. Hydatid cysts typically demonstrate characteristic imaging findings, however, the appearances may become complicated due to cyst rupture or secondary infection. Ultrasonography is the imaging modality of choice particularly in hepatic disease. CT best demonstrates cyst wall calcification and cyst infection. (+info)
Latent fatality due to hydatid cyst rupture after a severe cough episode.
(5/170)
Hydatid disease is a parasitic disease caused by Echinococcus granulosus characterised by cyst formation in various organs. The infestation mostly involves the liver. Hydatid cysts of the liver can rupture either spontaneously or due to trauma. Incidence of rupture is about 3-17% of all cases with hydatid disease. Unless treated surgically, rupture can result in death. Here, we present a case of hydatid cyst ruptured after a severe cough episode and disseminated first to the subcapsular area, then to the peritoneal space. Probably due to a decrease in parenchymal pressure in the liver after decompressive effect of rupture, the patient felt an improvement in abdominal pain, refused operation, and left the hospital on his own responsibility. This unfortunate relief resulted in a delay of 55 hours in management. The leakage of liquid materials into peritoneal space resulted in a severe inflammatory reaction and eventually death of the patient. The patient died of a late peritonitis rather than anaphylaxis, which is the most common reason for death in such patients. As a conclusion, physicians should be aware of a temporary relief in abdominal pain after cyst rupture that may cause a delay in management and in turn loss of patient due to peritonitis. (+info)
Short report: Inadequacy of yaks as hosts for the sheep dog strain of Echinococcus granulosus or for E. Multilocularis.
(6/170)
Hydatid disease (echinococcosis) has a two-host cycle involving the domestic dog and grazing animals. Humans are also infected by the dog. Both unilocular (Echinococcus granulosus in yaks, sheep, and goats) and multilocular (alveolar) (E. multilocularis in hares and rodents) hydatids are common in western Sichuan in the People's Republic of China. Humans and dogs are equally infected with both species. Many yaks (Bos grunniens) were found with multilocular cysts that visually were deemed to be E. multilocularis. However, a histologic and molecular study showed that they were actually E. granulosus. No infective cysts were found in 125 necropsied yaks. We conclude that the yak is an inadequate and dead-end host for the sheep dog (G1) strain of Echinococcus granulosus and also for E. multilocularis. (+info)
Reemergence of canine Echinococcus granulosus infection, Wales.
(7/170)
As a consequence of large-scale outdoor slaughter of sheep during the 2001 foot and mouth disease (FMD) outbreak in the United Kingdom and the possibility of increased risk for transmission of Echinococcus granulosus between sheep and dogs, a large survey of canine echinococcosis was undertaken in mid-Wales in 2002. An Echinococcus coproantigen-positive rate of 8.1% (94/1,164) was recorded on 22% of farms surveyed, which compares to a rate of 3.4% obtained in the same region in 1993. Positivity rates between FMD-affected properties and unaffected ones did not differ significantly. Significant risk factors for positive results in farm dogs were allowing dogs to roam free and the infrequent dosing (>4-month intervals) of dogs with praziquantel. When these data are compared to those of a previous pilot hydatid control program in the area (1983-1989), an increase in transmission to humans appears probable. (+info)
Comparative analysis of the diagnostic performance of six major Echinococcus granulosus antigens assessed in a double-blind, randomized multicenter study.
(8/170)
The serodiagnosis of hydatid disease is a valuable instrument for clinical diagnosis and epidemiological surveillance of high-risk populations. In the past decade a wealth of reports on the diagnostic performance of numerous antigens have been produced. However, their diagnostic value has been estimated under different conditions, using different serum collection, therefore precluding their direct comparison. Here we report an unbiased comparison of the same batch of six major E. granulosus antigens, namely, hydatid cyst fluid (HCF), native antigen B (AgB), two recombinant AgB subunits, an AgB-derived synthetic peptide, and recombinant cytosolic malate dehydrogenase from E. granulosus (EgMDH), against the same serum collection. The double-blind analysis was performed using a standardized protocol and receiver operating characteristic (ROC) data analysis by a network of six South American laboratories. High intercenter reproducibility was attained, and the intralaboratory analysis allowed the comparative ranking of the antigen panel. HCF, AgB, and its AgB8/1 subunit exhibited equivalent diagnostic efficiencies, 81.4% +/- 0.5%, 81.3% +/- 0.6%, and 81.9% +/- 2.0%, respectively; with a more favorable balance toward specificity in the case of the last antigen. The diagnostic efficiencies for the other three antigens were 76.8% +/- 6.8%, 69.1% +/- 2.7%, and 66.8% +/- 2.1%, for the peptide, the AgB8/2 subunit, and the EgMDH, respectively. The study also included an analysis of batch-to-batch variation in the diagnostic performance of different HCF regional preparations. Based on these results, a suggested recommendation on the use of these antigens was drawn. (+info)