ABSTRACT
Summary: Background. Heterogeneity in the design and quality of trials evaluating allergy immunotherapies (AITs) limits their comparability, making it difficult for physicians, patients, and payers to select the best treatment option. Methods. This systematic review evaluated the quality of randomised controlled trials (RCTs) of registered grass AITs using the National Institute of Health and Care Excellence checklist. Results. 17 of 44 unique RCTs (38.6%) (sample size range: 18-1,501 subjects) were subcutaneous grass immunotherapy trials and 27 (61.4%) were sublingual grass immunotherapy trials (Allergovit, 5 trials; Alutard, 8; Grazax, 13; Oralair, 6; Staloral, 8; Pollinex, 2; Phostal and Purethal, 1 each). Three trials (6.8%; all Grazax) fulfilled every quality criterion. Quality assessments revealed inconsistencies in study quality and reporting. Study quality trended towards improvement over time, particularly after 2009. Conclusions. When as-sessing grass AIT, it is important to focus not only on endpoints but also on the quality of evidence.
Subject(s)
Desensitization, Immunologic/methods , Rhinitis, Allergic/therapy , Desensitization, Immunologic/standards , Humans , Quality Assurance, Health Care , Randomized Controlled Trials as TopicABSTRACT
Since 1999, two Cooperia oncophora isolates, originally obtained from the United Kingdom, have been maintained by regular passage through calves at the Macdonald Campus, McGill University farm. One isolate, IVS, was originally susceptible to ivermectin, while the IVR isolate was originally resistant to ivermectin. These two isolates have been used to study the mechanisms of ivermectin resistance. To confirm the susceptible/resistant status after 4 years of passaging through calves, a controlled study was performed in which two worm-free calves were experimentally infected with IVS and another two worm-free calves with the IVR infective larvae. The calves were treated with ivermectin (0.2 mg/kg) subcutaneously (Ivomec Injection) 21 days after infection. Ivermectin at the recommended dose was 100% effective at eliminating the IVS isolate, since no eggs were found in feces, and no adult worms were found in the small intestine of the treated IVS-infected calf. In contrast, the IVR-infected calf continued to pass eggs in feces even after treatment with ivermectin, and adult worms (250) were found in the small intestine at necropsy. The untreated calves had 1,330 and 848 adult worms, respectively, for the IVS and IVR infected animals.
Subject(s)
Antinematodal Agents/therapeutic use , Ivermectin/therapeutic use , Trichostrongyloidea/drug effects , Trichostrongyloidiasis/drug therapy , Animals , Antinematodal Agents/administration & dosage , Antinematodal Agents/pharmacology , Cattle , Feces/parasitology , Intestine, Small/parasitology , Ivermectin/administration & dosage , Ivermectin/pharmacology , Parasite Egg Count , Parasitic Sensitivity Tests , Trichostrongyloidea/isolation & purification , Trichostrongyloidiasis/parasitologyABSTRACT
To increase the existent genetic variability in cysteine proteases, a polymorphism study was performed in Haemonchus contortus by comparing 2 different strains of the parasite: North American (NA) and Spanish (SP) strains. For this purpose, the polymorphism of 5 previously reported genes (AC-1, AC-3, AC-4, AC-5 and GCP-7) were analysed by PCR-SSCP and sequencing procedures. Based on the SSCP results, a total of 20 different alleles were identified for the 5 loci assessed. Except locus AC-5, all the loci were polymorphic. Loci AC-1, AC-3, AC-4 and GCP-7 showed 5, 8, 2 and 4 alleles, respectively. The allelic frequencies ranged from 0.0070 to 0.8560 and were significantly different between strains. In addition, nucleotide diversity analyses showed a significant variation within and between strains. The variations in the nucleotide sequence of the different alleles were translated in some cases into changes in the amino acid sequence. Evidence of genetic variability in cysteine proteases from two different strains of H. contortus for the same set of genes had not been previously reported.
Subject(s)
Cysteine Endopeptidases/genetics , Haemonchus/enzymology , Haemonchus/genetics , Alleles , Amino Acid Sequence , Animals , Base Sequence , DNA, Helminth/chemistry , DNA, Helminth/genetics , Genetic Variation/genetics , Male , Molecular Sequence Data , North America , Phylogeny , Polymerase Chain Reaction , Polymorphism, Single Nucleotide/genetics , Polymorphism, Single-Stranded Conformational , Sequence Alignment , SpainABSTRACT
The glutamate-gated chloride channels (GluCls) are members of the ligand-gated ion channel superfamily that are thought to be involved in the mode of action of ivermectin and mechanism of resistance. Using reverse-transcriptase PCR techniques, 2 full-length GluCl cDNAs, encoding GluClalpha3 and GluClbeta subunits, were cloned from Cooperia oncophora, a nematode parasite of cattle. The two sequences show a high degree of identity to similar subunits from other nematodes. The C. oncophora GluClalpha3 subunit is most closely related to the Haemonchus contortus GluClalpha3B subunit, while C. oncophora GluClbeta subunit shares high sequence identity with the H. contortus GluClbeta subunit. Using single-strand conformation polymorphism, the genetic variability of these two genes was analysed in an ivermectin-susceptible isolate and an ivermectin-resistant field isolate of C. oncophora. Statistical analysis suggested an association between the C. oncophora GluClalpha3 gene and ivermectin resistance. No such association was seen with the GluClbeta gene.
Subject(s)
Antinematodal Agents/pharmacology , Chloride Channels/genetics , Drug Resistance/genetics , Glutamic Acid/physiology , Ivermectin/pharmacology , Trichostrongyloidea/genetics , Amino Acid Sequence , Animals , Genetic Variation , Helminth Proteins/genetics , Ion Channel Gating/genetics , Molecular Sequence Data , Phylogeny , Sequence Alignment , Sequence Homology, Amino Acid , Trichostrongyloidea/physiologyABSTRACT
Two full-length beta-tubulin cDNAs, representing isotypes 1 and 2, were cloned from the cattle nematode Cooperia oncophora. The predicted protein sequences span 448 amino acids, and show a high degree of identity to beta-tubulins from other nematodes. While C. oncophora isotype 1 sequence had the highest identity to Haemonchus contortus isotype 1 and Teladorsagia circumcincta sequences (95% identity), the C. oncophora isotype 2 sequence was most similar to H. contortus isotype 2 and Trichostrongylus colubriformis (92% identity). Alignment of the two C. oncophora sequences with other trichostrongylid beta-tubulins deposited in GenBank showed a clear distinction between isotype 1 and 2 beta-tubulin classes. The two classes differed at 19 amino acid positions, most notably at the carboxy terminus. These isotype-defining residues were conserved among different trichostrongylid species within a class. Analysis of fragments of both genes revealed a high degree of genetic variability in coding and non-coding regions. However, all nucleotide differences detected in the coding region were silent, as they did not result in any amino acid substitution. Analysis of 2 groups of worms for the codon 200 polymorphism associated with benzimidazole resistance revealed a proportion of worms in 1 of the groups bearing a tyrosine at this position.
