HIV-1 drug-resistance patterns among patients on failing treatment in a large number of European countries

BACKGROUND

Information about patterns of HIV-1 drug resistance among treatment-exposed patients is crucial for the development of novel effective drugs. Currently no system exists that monitors patterns of resistance in patients failing therapy.

METHODS

The study included 1,988 HIV-1 sequences from patients experiencing therapy failure collected between 2000 and 2004 in 15 European countries. Genotypic resistance was interpreted using the ANRS algorithm. Phenotypic resistance was predicted using the Virco geno- to phenotype system.

RESULTS

80.7% of the sequences included at least one drug-resistance mutation. Mutations were found for NRTIs (73.5%), NNRTIs (48.5%), and protease inhibitors (35.8%). Ninety percent of sequences with genotypic resistance harbored M184V, M41L, K103N, D67N, and/or T215Y. Among NRTIs, resistance was most frequently predicted for lamivudine. About half of all sequences had reduced susceptibility for NNRTIs. Resistance to most boosted protease inhibitors was found in < 25%. No sequence had resistance to all currently available drugs.

CONCLUSION

Levels of resistance among patients with therapy failure were high. The patterns of resistance reflect resistance to drugs available for a longer time. Fully suppressive regimens can be designed even for the most mutated HIV because boosted protease inhibitors have remained active against most circulating viruses and new drug classes have become available.

Cytochemistry and immunolocalisation of polysaccharides and proteoglycans in the endosperm of green Arabica coffee beans

The major noncellulosic polysaccharides and proteoglycans in the coffee bean (Coffea arabica) cell wall are (galacto)mannans and arabinogalactan proteins. Immunological and chemical probes demonstrated that the mannans and arabinogalactan proteins were located continuously across the width of the cell wall, but that the concentration of different structural epitopes within these polysaccharide types showed considerable spatial variation. For the mannans this was implied by the striated pattern demonstrated by fluctuation of the affinity between the mannan monoclonal antibody BGM C6 and (galacto)mannan. The arabinogalactan proteins labelled by the Yariv reagent and the arabinogalactan protein-specific antibody LM2 appeared to be located in all regions of the wall except the middle lamella, but showed some differences in intensity of labelling. However, the LM6 antibody, specific for (1-->5)-alpha-arabinan epitopes, was located only as a compact region adjacent to the cell lumen in the body of the endosperm; though, it did label throughout the wall of epidermal cells. This implied that either some of the more highly arabinosylated arabinogalactan proteins contained contiguous 5-arabinosyl residues or that a rhamnogalacturonan which contained 5-arabinosyl residues as side chains existed in the cell wall. In either case the polymers were very restricted in their distribution. A second category of pectin, a homogalacturonan detected by JIM7, was located only in the middle lamella region. The architecture of the wall, as revealed by resin etching, appeared to reflect the chemical heterogeneity, with three distinct physical zones identifiable in a cross section across a single wall.

Provision of acupuncture in a university health centre--a clinical audit

A retrospective audit was carried out between May 1999 and April 2000 at a university-based acupuncture clinic. Two acupuncturists saw a total of 69 clients of whom three-quarters were female; just over a third were less than 29 years of age; two-thirds were below the age of 40; 67% of clients were Caucasians; a third smoked; three-quarters currently consumed some alcohol. Most had no experience of using complementary and alternative medicine (CAM), therefore the service provided the first access to CAM. Of those attending a follow-up appointment, 43 (80%) reported feeling better, 10 the same and one worse. No side-effects were reported by 50 (73%) clients, but four reported minor side-effects (one bruising and three drowsiness). The process of carrying out the audit provided the opportunity for the practitioners to reflect on their clinical practice and improve service delivery.

Ambulatory adenotonsillectomy in children less than 5 years of age

OBJECTIVE

Post-tonsillectomy monitoring has received a significant amount of attention in recent years. Although the literature questions the safety of ambulatory adenotonsillectomy in children less than 5 years of age, age alone did not exclude eligibility for day surgery at our institution.

METHOD

A retrospective chart review was performed between 1995 and 1998 for all children who had undergone adenoidectomy or adenotonsillectomy at the London Health Sciences Centre in London, ON.

RESULTS

There were 119 adenoidectomies and 278 adenotonsillectomies performed. The average age was 3 years at the time of surgery. One hundred and ninety-six cases were performed for obstruction, and 201 were done for infection. Average time spent in the postanaesthesia care unit was 6 hours for adenotonsillectomy and 4.5 hours for adenoidectomy. There were 26 planned and 60 unplanned admissions. One (4/397) percent of the unplanned admissions were for postoperative hemorrhage; 14% (56/397) were for vomiting and dehydration. No cases were admitted for postoperative desaturations or hypotensive episodes. The readmission rate was 0%.

CONCLUSIONS

Ambulatory adenotonsillectomy is a safe procedure in children less than 5 years old. However, a well-informed, reliable caretaker and support from the day surgery staff is essential in early discharge of young patients after adenotonsillectomy.

A novel alpha-amylase gene is transiently upregulated during low temperature exposure in apple fruit

An alpha-amylase gene product was isolated from apple fruit by reverse-transcriptase PCR using redundant primers, followed by 5' and 3' RACE. The gene is a member of a small gene family. It encodes a putative 46.9 kDa protein that is most similar to an alpha-amylase gene from potato (GenBank accession M79328). In apple fruit this new gene was expressed at low levels, as detected by reverse-transcriptase PCR, in a number of plant tissues and during fruit development. Highest levels of mRNA for this transcript were observed 3 to 9 days after placing apple fruit at 0.5 degrees C. Phylogenetic analysis of amino acid sequence places the potato and apple proteins as a distinct and separate new subgroup within the plant alpha-amylases, which appears to have diverged prior to the split between monocotyledonous and dicotyledonous plants. These two divergent alpha-amylases lack the standard signal peptide structures found in all other plant alpha-amylases, and have sequence differences within the B-domain and C-domain. However, comparisons with structures of known starch hydrolases suggest that these differences are unlikely to affect the enzymatic alpha-1,4-amylase function of the protein. This is the first report of upregulation of a dicotyledonous alpha-amylase in response to low temperature, and confirms the presence of a new family of alpha-amylases in plants.

Localization of Cell Wall Polysaccharides during Kiwifruit (Actinidia deliciosa) Ripening

The localization of pectin, cellulose, xyloglucan, and callose was compared in kiwifruit (Actinidia deliciosa [A. Chev.] C. F. Liang and A. R. Ferguson var. deliciosa "Hayward") at harvest, at the end of the first phase of softening, and when ripe. Pectin was visualized using three different methods: labeling of galacturonic acid residues, labeling of negatively charged groups, and labeling with JIM 5 (nonesterified residues) and JIM 7 (methyl-esterified) monoclonal antibodies. Labeling of pectin gave different results depending on the detection system used. Differences related to patterns of change during ripening and to spatial distribution of label intensity. Cell wall pectin was available for labeling at all stages of fruit softening, but no clear differentiation of the middle lamella region was seen, although JIM 5 binding predominated where the middle lamellae joined the intercellular spaces in unripe fruit. Negatively charged groups (cationic gold labeling) and, to a lesser extent, galacturonic acid residues (Aplysia depilans gonad lectin labeling) were preferentially located near the cell wall/plasma membrane boundary. The lack of strong binding of the JIM antibodies indicated that the reactive groups were inaccessible. Cellulose remained intact and labeled densely across the wall at all stages of fruit ripening. Distribution of xyloglucan was patchy at harvest but was scattered throughout the wall later in ripening. Alterations to labeling of xyloglucan indicated that some epitopes were differentially exposed. Plasmodesmatal regions were clearly different in composition to other wall areas, showing an absence of cellulose labeling, specific pectin labeling, and callose presence. A similar predominance of pectin labeling compared with cellulose also occurred at the middle lamella wedge near intercellular spaces.

Sucrose-phosphate synthase steady-state mRNA increases in ripening kiwifruit

Early during fruit ripening in kiwifruit (Actinidia deliciosa var. deliciosa [A. Chev.], C.F. Liang and A.R. Ferguson cv. Hayward), starch is broken down to sucrose and hexose sugars. Concomitantly, sucrose-phosphate synthase (SPS, EC 2.3.1.14) activity measured with saturating substrate increased, suggesting that SPS is induced in response to a higher requirement for sucrose synthesis. A 2584 bp long partial cDNA clone encoding SPS was isolated from ripening kiwifruit. cDNA fragments encoding the 5' end were isolated by PCR, and sequencing revealed at least four closely related (> 96% identity) mRNAs expressed early in kiwifruit ripening. Southern hybridisations in a diploid relative of kiwifruit, Actinidia chinensis (Planch.) var. chinensis, were consistent with the presence of a small gene family. Western analysis indicated a 125 kDa SPS protein present in all tissues of A. chitensis at all stages of development. Steady-state levels of SPS mRNA in A. chinensis increased near fruit maturity as net starch degradation began on the vine, and increased again during ethylene treatment of fruit after harvest. After removal from ethylene SPS transcript levels decreased, only to increase again as fruit moved into the climacteric and starch breakdown was completed. Exposure to low temperatures also caused an increase in SPS transcript level. These results indicate that SPS mRNA increases in kiwifruit in response to the presence of new substrate sourced from starch degradation, in response to ethylene and in response to low temperature.

Purification, cloning and expression of spinach leaf sucrose-phosphate synthase in Escherichia coli

Sucrose-phosphate synthase (SPS) from leaves of spinach (Spinacia oleracea L.) has been purified to homogeneity by a procedure involving precipitation with polyethylene glycol and chromatography over diethylaminoethylcellulose, omega-aminohexyl-agarose, Mono Q and Blue Affinity columns. The purification factor was 838 and the final specific activity was 1.3 nkat.(mg protein)-1. On denaturing gels the major polypeptide was 120 kDa but there was also a variable amount of smaller polypeptides in the range of 90 to 110 kDa. A new activity stain was developed to allow visualization of SPS in gels. The holoenzyme had a molecular weight of about 240 and 480 kDa in native gels and Sepharose, respectively. A high-titre polyclonal antibody was obtained which reacted with SPS from other species including wheat, potato, banana and maize. Screening of a spinach-leaf cDNA-expression library with the antibody allowed the isolation of a full-length clone. Sequencing revealed a predicted molecular weight of 117649 Da, and considerable homology with the recently published sequence for maize leaf (Worrell et al. 1991, Plant Cell 3, 1121-1130). Expression of the spinach-leaf SPS gene in Escherichia coli resulted in biological activity, revealed by the presence of SPS activity in extracts and the accumulation of sucrose-6-phosphate and sucrose in the bacteria.