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PubMed2002

Association of the T-G polymorphism in adiponectin (exon 2) with obesity and insulin sensitivity: interaction with family history of type 2 diabetes.

The adipocyte-derived hormone adiponectin seems to protect from insulin resistance, a key factor in the pathogenesis of type 2 diabetes. Genome-wide scans have mapped a susceptibility locus for type 2 diabetes and the metabolic syndrome to chromosome 3q27, where the adiponectin gene is located. A common silent T-G exchange in nucleotide 94 (exon 2) of the adiponectin gene has been associated with increased circulating adiponectin levels. Metabolic abnormalities associated with the G allele have not been reported. We therefore assessed whether this polymorphism alters insulin sensitivity and/or measures of obesity using the Tübingen Family Study database (prevalence of the G allele, 28%). In 371 nondiabetic individuals, we found a significantly greater BMI in GG + GT (25.5 +/- 0.7 kg/m(2)) compared with TT (24.1 +/- 0.3 kg/m(2); P = 0.02). Insulin sensitivity (determined by euglycemic clamp, n = 209) was significantly lower in GG + GT (0.089 +/- 0.007 units) compared with TT (0.112 +/- 0.005 units; P = 0.02). This difference disappeared completely on adjustment for BMI. Because our population contains a relatively high proportion of first-degree relatives of patients with type 2 diabetes, we stratified by family history (FHD). Much to our surprise, the genotype differences in BMI and insulin sensitivity in the whole population were attributable entirely to differences in the subgroup without FHD, whereas in the subgroup with FHD, the G allele had absolutely no effect. Moreover, individuals without FHD had a significantly lower BMI than individuals with FHD (25.2 +/- 0.4 vs. 26.2 +/- 0.5 kg/m(2); P = 0.01), which was not the case for the GG + GT subgroup without FHD (27.0 +/- 0.9 kg/m(2); NS). This suggests that in individuals without familial predisposition for type 2 diabetes, the adiponectin polymorphism may mildly increase the obesity risk (and secondarily insulin resistance). In contrast, in individuals who are already burdened by other genetic factors, this small effect may be very hard to detect.

Adipocytes↗
PubMed1995

Informational suppression to investigate structural functional and evolutionary aspects of the Erwinia chrysanthemi cellulase EGZ.

The cellulase EGZ produced by the plant pathogen Erwinia chrysanthemi belongs to family 5 of the beta-glycohydrolases (also referred to as cellulase family A), which contains over 40 members from Gram-negative and Gram-positive bacteria and fungi. Amber mutations were introduced into 16 codons of the celZ gene encoding EGZ. Targeted residues included: (1) two Glu, two His and one Arg residue, strictly conserved throughout family 5; (2) one Arg and one His residue conserved in sub-family 5-2; and (3) one His and six Arg residues not conserved at all. Each amber allele was introduced into 13 Escherichia coli strains each carrying a different suppressor tRNA that inserts an amino acid at the mutated position. In vivo stability of the mutated forms of EGZ and their cellulase activity were analysed as well as suppression efficiency. For some positions of particular interest, missense mutations were introduced into the celZ gene either to confirm the effect of the suppressor-mediated amino acid substitution or to broaden the spectrum of mutations available. The substitution patterns of the two Glu positions were interpretable in the light of the stereospecificity of the reaction catalysed by EGZ: Glu133 and Glu220 are proposed to act as a proton donor and as a nucleophile, respectively, forming the glycosyl-enzyme intermediate. Substitution at His-occupied positions, including two non-conserved positions, yielded proteins affected in their catalytic activity but not their in vivo stability. In particular, evidence was obtained for His at position 98 to be involved in interactions with the substrate. The view that Arg residues are important in stabilizing proteins was supported by the identification of three Arg residues, whose substitution yielded thermosensitive forms of EGZ. In addition, Pro substitutions of any of the six Arg residues altered protein stability in vivo but the substitutions scored almost neutral for activity. Five positions, predicted to be within alpha-helices, were found to be susceptible to Pro substitutions (but not to Ala) with respect to stability in vivo. Overall, the systematic alteration of all His and Arg residues coupled with the simultaneous analysis of activity and in vivo stability allowed us to demonstrate that substitution matrices vary at each position and for each biological property considered. Ideally, therefore, substitution matrices used in sequence alignment procedures should be reconsidered as position-specific and as property-specific.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed2005

Association analysis of mild mental impairment using DNA pooling to screen 432 brain-expressed single-nucleotide polymorphisms.

We hypothesize that mild mental impairment (MMI) represents the low extreme of the same quantitative trait loci (QTLs) that operate throughout the distribution of intelligence. To detect QTLs of small effect size, we employed a direct association strategy by genotyping 432 presumably functional nonsynonymous single-nucleotide polymorphisms (nsSNPs) identified from public databases on DNA pools of 288 cases and 1025 controls. In total, 288 MMI cases were identified by in-home administration of McCarthy Scales of Children's Abilities to 836 twin pairs selected from a community sample of more than 14 000 children previously screened for nonverbal cognitive delay using parentally administered tests. Controls were selected from the community sample representing the full range of nonverbal intelligence. SNPs showing at least 7% allele frequency differences between case and control DNA pools were tested for their association with the full range of nonverbal intelligence using five DNA subpools, each representing quintiles of the normal quantitative trait scores from the 1025 controls. SNPs showing linear associations in the expected direction across quintiles using pooled DNA were individually genotyped for the 288 cases and 1025 controls and analyzed using standard statistical methods. One SNP (rs1136141) in HSPA8 met these criteria, yielding a significant (P=0.036) allelic frequency difference between cases and controls for individual genotyping and a significant (P=0.013) correlation within the control group that accounts for 0.5% of the variance. The present SNP strategy combined with DNA pooling and large samples represents a step towards identifying QTLs of small effect size associated with complex traits in the postgenomic era when all functional polymorphisms will be known.

Brain↗
PubMed2005

Frequency of administration of recombinant human erythropoietin for anaemia of end-stage renal disease in dialysis patients.

BACKGROUND: The benefits of recombinant human erythropoietin (rHuEPO) administration in dialysis patients have been demonstrated, however the optimal frequency regimen have yet to be established. OBJECTIVES: To assess the effects of different frequency regimens of rHuEPO administration in dialysis patients on anaemia correction, quality of life and optimal use. SEARCH STRATEGY: We searched 13 electronic databases (1980 to May 2001) the internet (August 1997), handsearched Kidney International (1983 to May 1997), contacted known investigators, biomedical companies, and screened reference lists of relevant articles. Most recent search: The Cochrane Renal Group's specialised register (June 2004) and The Cochrane Library (Issue 3, 2004). SELECTION CRITERIA: Randomised controlled trials (RCTs) or quasi-RCTs comparing different frequencies of rHuEPO administration in dialysis patients. We compared haemodialysis and CAPD patients and subcutaneous and intravenous administration. DATA COLLECTION AND ANALYSIS: Quality assessment was performed by two assessors. Data were abstracted by a single author onto a standard form, and a sample was checked by another author. Results were expressed as relative risk (RR) or weighted mean difference (WMD) with 95% confidence intervals (CI). MAIN RESULTS: Eleven studies (719 patients) were included. There was no significant difference in maintaining target haemoglobin for once versus twice weekly administration (one study, 20 patients: RR 1.00, 95% CI 0.42 to 2.40) or mean haemoglobin after 12 weeks of therapy between haemodialysis and CAPD patients (two studies: WMD -0.21 g/dL, 95% CI -0.98 to 0.56) At the end of study for once versus thrice weekly administration (three studies: SMD -0.31, 95% CI -0.67 to 0.06) and at the end of maintenance phase (one study: WMD -0.2 g/dL, 95% CI -0.65 to 0.25) there was no significant difference. More rHuEPO was required by haemodialysis patients receiving once weekly versus twice weekly doses (WMD 12.0 U/kg, 95% CI 0.24 to 23.76). No difference was found for CAPD patients alone or combined (WMD 4.38 U/kg, 95% CI -11.28 to 20.04). Once versus thrice weekly administration was not significant (WMD 10.00 U/kg, 95% CI -80.87 to 100.87). There was no difference in the frequency of adverse events. AUTHORS' CONCLUSIONS: There is no significant difference between once weekly versus thrice weekly subcutaneous administration of rHuEPO. Once weekly administration would require an additional 12 U/kg/wk for patients on haemodialysis, however this is based on one very small study. Cost of additional rHuEPO needs to assessed with regard to patient preference and compliance.

Anemia↗
PubMed2004

A novel family of P-loop NTPases with an unusual phyletic distribution and transmembrane segments inserted within the NTPase domain.

BACKGROUND: Recent sequence-structure studies on P-loop-fold NTPases have substantially advanced the existing understanding of their evolution and functional diversity. These studies provide a framework for characterization of novel lineages within this fold and prediction of their functional properties. RESULTS: Using sequence profile searches and homology-based structure prediction, we have identified a previously uncharacterized family of P-loop NTPases, which includes the neuronal membrane protein and receptor tyrosine kinase substrate Kidins220/ARMS, which is conserved in animals, the F-plasmid PifA protein involved in phage T7 exclusion, and several uncharacterized bacterial proteins. We refer to these (predicted) NTPases as the KAP family, after Kidins220/ARMS and PifA. The KAP family NTPases are sporadically distributed across a wide phylogenetic range in bacteria but among the eukaryotes are represented only in animals. Many of the prokaryotic KAP NTPases are encoded in plasmids and tend to undergo disruption to form pseudogenes. A unique feature of all eukaryotic and certain bacterial KAP NTPases is the presence of two or four transmembrane helices inserted into the P-loop NTPase domain. These transmembrane helices anchor KAP NTPases in the membrane such that the P-loop domain is located on the intracellular side. We show that the KAP family belongs to the same major division of the P-loop NTPase fold with the AAA+, ABC, RecA-like, VirD4-like, PilT-like, and AP/NACHT-like NTPase classes. In addition to the KAP family, we identified another small family of predicted bacterial NTPases, with two transmembrane helices inserted into the P-loop domain. This family is not specifically related to the KAP NTPases, suggesting independent acquisition of the transmembrane helices. CONCLUSIONS: We predict that KAP family NTPases function principally in the NTP-dependent dynamics of protein complexes, especially those associated with the intracellular surface of cell membranes. Animal KAP NTPases, including Kidins220/ARMS, are likely to function as NTP-dependent regulators of the assembly of membrane-associated signaling complexes involved in neurite growth and development. One possible function of the prokaryotic KAP NTPases might be in the exclusion of selfish replicons, such as viruses, from the host cells. Phylogenetic analysis and phyletic patterns suggest that the common ancestor of the animals acquired a KAP NTPase via lateral transfer from bacteria. However, an earlier transfer into eukaryotes followed by multiple losses in several eukaryotic lineages cannot be ruled out.

Adenosine Triphosphatases↗
PubMed2000

Clinical strategy for the development of angiogenesis inhibitors.

Angiogenesis inhibitors differ from conventional cytotoxic chemotherapy agents by targeting normal cells rather than tumor cells, which may contain multiple mutations. Because of this, the traditional strategy used in clinical development of cytotoxic agents may not be appropriate for these novel agents. Many clinical studies are now evaluating these agents with a new approach, referred to as the cytostatic paradigm. The cornerstone of the cytostatic paradigm is the use of time to progression (TTP) of disease as the decision-making criterion for "go/no go" in the early phases of clinical development. However, the use of TTP as the main criterion for clinical trials is complicated for a variety of reasons, including: A) the lack of standardized criteria accepted by regulatory authorities; B) the heterogeneity of the historical database, and C) the larger number of patients needed for the "go/no go" decision-making process. In addition, clinical trials of cytotoxic agents have traditionally used objective response (despite the controversy regarding objective response as a surrogate for clinical activity) as the main criterion for determining whether the results of phase II studies justify the pivotal phase III studies. Another aspect of the clinical development strategy is combining angiogenesis inhibitors with cytotoxic chemotherapy. The rationale for combination of angiogenesis inhibitors with cytotoxic agents is based on: A) different targets for these agents; B) lack of cross-resistance patterns; C) lack of myelosuppression with angiogenesis inhibitors allows administration of full doses of all agents, and D) the assumption that combining these agents will result in additive antitumor activity. Combination therapy with angiogenesis inhibitors may be attractive to both clinicians and their patients because it allows cytostatic agents to be used upfront in treatment while contributing to drug registration strategy (cytostatic/cytotoxic combination therapy versus cytotoxic therapy). The clinical development of the angiogenesis inhibitor SU5416, a small molecule inhibitor of vascular endothelial growth factor, is currently ongoing. In phase I trials, SU5416 demonstrated activity in both colorectal and non-small-cell lung cancer patients. Based on these encouraging results, phase III studies to evaluate combination of SU5416 with established cytotoxic therapy are planned. These studies will include an interim analysis, the equivalent of a phase II evaluation of clinical activity. If successful, this strategic approach will save significant time in the clinical development process.

Angiogenesis Inhibitors↗
PubMed1999

Visualizing and quantifying molecular goodness-of-fit: small-probe contact dots with explicit hydrogen atoms.

The technique of small-probe contact dot surfaces is described as a method for calculating and displaying the detailed atomic contacts inside or between molecules. It allows one both to measure and to visualize directly the goodness-of-fit of packing interactions. It requires both highly accurate structures and also the explicit inclusion of all hydrogen atoms and their van der Waals interactions. A reference dataset of 100 protein structures was chosen on the basis of resolution (1.7 A or better), crystallographic R-value, non-homology, and the absence of any unusual problems. Hydrogen atoms were added in standard geometry and, where needed, with rotational optimization of OH, SH, and NH+3 positions. Side-chain amide orientations were corrected where required by NH van der Waals clashes, as described in the accompanying paper. It was determined that, in general, methyl groups pack well in the default staggered conformation, except for the terminal methyl groups of methionine residues, which required rotational optimization. The distribution of serious clashes (i.e. non-H-bond overlap of >/=0.4 A) was studied as a function of resolution, alternate conformations, and temperature factor (B), leading to the decision that packing and other structural features would not be analyzed for residues in 'b' alternate conformations or with B-factors of 40 or above. At the level of the fine details analyzed here, structural accuracy improves quite significantly over the range from 1.7 to 1.0 A resolution. These high-resolution structures show impressively well-fitted packing interactions, with some regions thoroughly interdigitated and other regions somewhat sparser. Lower-resolution structures or model structures could undoubtedly be improved in accuracy by the incorporation of this additional information: for example, nucleic acid structures in non-canonical conformations are often very accurate for the bases and much less reliable for the backbone, whose conformation could be specified better by including explicit H atom geometry and contacts. The contact dots are an extremely sensitive method of finding problem areas, and often they can suggest how to make improvements. They can also provide explanations for structural features that have been described only as empirical regularities, which is illustrated by showing that the commonest rotamer of methionine (a left-handed spiral, with all chi values near -60 degrees) is preferred because it provides up to five good H atom van der Waals contacts. This methodology is thus applicable in two different ways: (1) for finding and correcting errors in structure models (either experimental or theoretical); and (2) for analyzing interaction patterns in the molecules themselves.

Crystallography, X-Ray↗
PubMed2006

Identification and characterization of syntaxin 1 antisense variants in Limulus polyphemus.

1.A Limulus SMART(TM) cDNA library screening resulted in the cloning of four syntaxin 1 homologs (referred to as Limulus syntaxin [Lim-syn] 1A, 1B, 1C, and 1D) (Wang, Y., Cao, Z., Xu, W., Kemp, M. D., McAdory, B. S., Newkirk, R. F., Ivy, M. T., and Townsel, J. G. (2004). Gene 326:189-199) and two novel intron-retaining syntaxin 1-like variants, designated Limulus syntaxin variant [Lim-synV] 1A/1C and Lim-synV 1B/1D. 2.The variants exhibited high amino acid sequence identity with the four syntaxin 1 homologs. Specifically, Lim-synV 1A/1C and Lim-synV 1B/1D were homologous to Lim-syn 1A/1C and Lim-syn 1B/1D, respectively. Surprisingly, both Lim-synV 1A/1C and 1B/1D are unusual in that each has a poly A+ tail, an intron, and the common splice motif "GT-AG" at the intron-exon boundary. Exons one and two on the complementary transcript of Lim-synV 1B/1D are separated by a 150 bp intron beginning at #95/96 of the predicted sequences for Lim-syn 1B and 1D, respectively. 3. In contrast, examination of the approximately 3.17 kb Lim-synV 1A/1C clone indicated the inclusion of an insert of 1120 base pairs (bp) beginning at codon #37/38 of the predicted Lim-syn 1A and 1C cDNAs' open reading frames (ORFs). Further, the intron sequence of Lim-synV 1A/C contained multiple stop codons and showed no significant homology to other known sequences as determined by a search of the GenBank database. Thus, the focus of this paper will be Lim-synV 1B/D exclusively. 4. To substantiate that an intron is retained in the full-length mRNA, two types of syntaxin cDNA fragments for Lim-syn 1B/D were generated by RT-PCR and analyzed on Northern blots. The products generated were a mixture of intron-retaining, as well as intron-spliced products. The syntaxin-like variants that retained the intron presumably are derived from a mRNA molecule that has not undergone splicing.5. Although the significance of such intron-containing mRNAs in Limulus has not yet been elucidated, future studies of such variants may serve to broaden our knowledge concerning established splicing mechanisms as well as to focus attention on nonconventional concepts about gene product regulation.

Amino Acid Sequence↗
PubMed1998

Treatment of Adamantiades-Behçet disease with systemic interferon alfa.

OBJECTIVE: To evaluate the efficacy and safety of systemic interferon alfa treatment in patients with Adamantiades-Behçet disease. DATA SOURCES: Reports and abstracts published in 1986 through 1997 in all languages were identified by the MEDLINE database, the Reference Index Related to Behcet's Disease, the Behçet disease conference proceedings, and abstract booklets. The indexing terms used Behçet and interferon. STUDY SELECTION: Twenty-two reports identified were included to estimate the efficacy of interferon alfa on mucocutaneous, ocular, and joint manifestations. Responses of individual mucocutaneous signs were evaluated in 8 reports. Adverse effects were sufficiently documented in 12 reports. All patients met the criteria of the Behçet Syndrome Research Committee of Japan or those of the International Study Group for Behçet's Disease. DATA EXTRACTION: Data were extracted and evaluated according to the following criteria: complete remission, disappearance of all manifestations during treatment; partial remission, greater than 50% decrease in the number, severity, duration and/or frequency of recurrence of the lesions; stable disease, less than 50% change in the manifestations; and progressive disease, greater than 50% deterioration of existing manifestations or/and the development of new ones. DATA SYNTHESIS: Systemic interferon alfa has been administered in 144 patients with Adamantiades-Behçet disease by subcutaneous or intramuscular injections of 3 to 18 x 10(6) units of interferon alfa-2a (70 patients) or 3 to 5 x 10(6) units of interferon alfa-2b (74 patients) daily or 3 times per week for 1 to 60 months. Seventy-four percent (92/124) of patients with mucocutaneous manifestations, 95% (37/39) of patients with uveitis, and 93% (51/55) of patients with arthropathy/arthritis exhibited a partial or complete response. Interferon alfa-2a regimens were more effective than interferon alfa-2b ones on mucocutaneous (47% vs 7% complete response) and ocular (67% vs 8% complete response; P < .001) manifestations. Mucocutaneous and ocular manifestations responded within 1 to 4 months after initiation of therapy. Thirty-eight percent (20/52) of patients with mucocutaneous lesions, 73% (8/11) of patients with uveitis, and 88% (21/24) of patients with arthropathy/arthritis experienced recurrences immediately or up to 7 months after discontinuation of treatment. Mild adverse effects were generally recorded; transient influenza-like symptoms (87% vs 63%; P < .05) and reversible leukopenia (24% vs 4%; P < .05) occurred more often under interferon alfa-2a regimens, while reversible mild alopecia was more common in patients receiving interferon alfa-2b (2% vs 28%; P < .01). CONCLUSIONS: Systemic interferon alfa treatment is reasonable for Adamantiades-Behçet disease. A 3-month high-dose regimen (9 x 10(6) units 3 times per week) followed by a low maintenance dose (3 x 10(6) units 3 times per week) is recommended.

Adolescent↗
PubMed2004

Pegylated interferon alpha-2a and -2b in combination with ribavirin in the treatment of chronic hepatitis C: a systematic review and economic evaluation.

OBJECTIVES: To assess the clinical-effectiveness and cost-effectiveness of pegylated interferon-alpha combined with ribavirin in the treatment of chronic hepatitis C. DATA SOURCES: Electronic databases, reference lists of retrieved reports, and the industry submissions to the National Institute for Clinical Excellence. REVIEW METHODS: Sources were rigorously searched and studies were selected that met the inclusion criteria of being randomised controlled trials (RCTs) involving comparisons between pegylated interferon-alpha plus ribavirin and non-pegylated interferon plus ribavirin (two trials) or pegylated interferon alone and non-pegylated interferon alone (four trials). The primary outcome in all trials was sustained virological response (SVR) at follow-up. The trials were generally of good quality, although reporting of methodological details could have been more thorough in places. A cost-effectiveness model followed a hypothetical cohort of 1000 individuals with chronic hepatitis C over a 30-year period. RESULTS: In the two trials that tested pegylated interferon plus ribavirin against non-pegylated interferon plus ribavirin the combined percentage of sustained virological response was 55%. The relative risk (RR) for remaining infected was reduced by 17% for pegylated interferon plus ribavirin compared with non-pegylated interferon plus ribavirin. Response to therapy varied according to viral genotype. Patients with genotype 1 had the lowest levels of sustained virological response and patients with genotype 2 or 3 had the highest. In the four trials that evaluated pegylated interferon monotherapy against non-pegylated interferon the combined sustained virological response rates were 31% for pegylated interferon and 14% for non-pegylated interferon. The RR for remaining infected with hepatitis C was reduced by 20% with the use of pegylated interferon. Patients with genotype 1 had the lowest levels of sustained virological response. There were also variations in sustained virological response according to other prognostic variables such as baseline viral load. Regimens involving pegylated interferon appear to be fairly well tolerated. Adverse events were been reported, but they did not differ substantially from levels of adverse events in regimens involving non-pegylated interferon. The incremental discounted cost per QALY for comparing no active treatment to 48 weeks of dual therapy with pegylated interferon and ribavirin (PEG + RBV) was 6045 pounds sterling. When moving from 48 weeks of dual therapy with non-pegylated interferon and ribavirin (IFN + RBV) to 48 weeks of dual therapy with PEG + RBV the figure was 12,123 pounds sterling. Subgroup analyses for dual PEG + RBV therapy demonstrated that the most favourable incremental discounted cost per QALY estimates were for patients infected with genotypes 2 and 3, and with low baseline viral load (3921 pounds sterling) compared with no active treatment. Results of one-way sensitivity analyses showed that the estimates varied according to differences in SVRs, drug costs and discount rates. In general estimates remained under 30,000 pounds sterling per QALY. The incremental discounted cost per QALY when moving from no active treatment to 48 weeks of monotherapy with pegylated interferon was 6484 pounds sterling. When moving from 48 weeks of monotherapy with IFN to 48 weeks of monotherapy with PEG the figure was 8404 pounds sterling. As with dual therapy, the lowest incremental cost per QALY was for patients with genotypes 2 and 3 and low baseline viral load, in the range 2641-4194 pounds sterling. The highest estimates were for patients with genotype 1 and high baseline viral load, around 30,000 pounds sterling. CONCLUSIONS: Well-designed RCTs show that patients treated with pegylated interferon, both as dual therapy and as monotherapy, experience higher sustained viral response rates than those treated with non-pegylated interferon. Patients with genotypes 2 and 3 experience the highest response, with rates in excess of 80%. Patients with the harder to treat genotype 1 nevertheless benefit, with up to 46% of patients experiencing an SVR in one of the trials. Pegylated interferon also appears to be relatively cost-effective in both monotherapy and dual therapy, with cost per QALY estimates remaining generally under 30,000 pounds sterling. The most favourable estimates were for patients with genotypes 2 and 3. Pegylated interferon is a relatively new intervention in the treatment of hepatitis C and therefore there are areas where further research is needed. These include: efficacies of therapy with PEG-alpha-2a vs PEG-alpha-2b; retreatment of previous non-responders using pegylated interferon; efficacy of treatments and long-term outcomes in patients who have other co-morbidities; prospective tests of rules governing stopping treatment; treating patients with acute hepatitis C; problems that may occur in a minority of patients with hepatitis C, such as cryoglobulinaemia and vasculitis; additional psychological effects on quality of life due to hepatitis C and also on the treatment of children and adolescents with hepatitis C.

Antiviral Agents↗
PubMed2003

Ear drops for the removal of ear wax.

BACKGROUND: Problems attributed to the accumulation of wax (cerumen) are one of the most common reasons for people to present to their general practitioners with ear trouble (Sharp 1990). Treatment for this condition often involves use of a wax softening agent (cerumenolytic) in order to disperse the cerumen and reduce the need for syringing, or to facilitate syringing should it prove necessary, but there is no consensus on the effectiveness of the wide variety of cerumenolytics in use. OBJECTIVES: To assess the effectiveness of ear drops (cerumenolytics) for the removal of symptomatic ear wax. SEARCH STRATEGY: We searched the Cochrane ENT Group Register, the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, 2003), and MEDLINE and EMBASE up to March 2003. Reference lists of all trials were also manually searched. SELECTION CRITERIA: We identified all randomised controlled trials (with or without blinding) in which a cerumenolytic was evaluated in comparison with either no treatment, a placebo, or other cerumenolytics in participants with hard or impacted ear wax, and in which the proportion of participants with sufficient clearance of the external canal to make further mechanical clearance unnecessary (primary outcome measure) was stated or calculable. The full text articles of all the retrieved trials of possible relevance were reviewed by the two reviewers and the inclusion criteria applied independently. Any differences in opinion about which studies to include in the review were resolved by discussion. DATA COLLECTION AND ANALYSIS: Trials were graded for methodological quality using the Cochrane approach. Data extraction was performed in a standardised manner by one reviewer and rechecked by the other reviewer, and where necessary investigators were contacted to obtain missing information. Meta-analysis was neither possible nor considered appropriate because of the heterogeneity of the treatments, treatment amounts and durations, trial procedures, and scoring systems. A narrative overview of the results is therefore presented. MAIN RESULTS: Eight trials satisfied the inclusion criteria, the majority of which were of poor quality. In all, 587 participants received one of nine different cerumenolytics. One trial compared active treatments with no treatment, two trials compared active treatments with water or a saline 'placebo', and all eight trials placed two or more active treatments in head-to-head comparisons. Seven trials included syringing as a secondary treatment where necessary.Overall, results were inconclusive. One trial found a significant difference between one of three active agents (Cerumol) in comparison to no treatment, but no statistically significant difference was found between these three agents (sodium bicarbonate ear drops; Cerumol; sterile water). In two trials no statistical difference was found between the effectiveness of either sodium bicarbonate ear drops, Cerumol, Cerumenex or Colace versus a sterile water or saline 'placebo'. Three trials (from the same source) found statistically significant differences in favour of the same active agent (Exterol) in comparison to glycerol and Cerumol. Three trials found no statistically significant difference between two or more cerumenolytics (Otocerol versus Cerumol; Audax versus Earex; sodium bicarbonate ear drops versus Cerumol). Two trials comparing the same two cerumenolytics (Cerumenex versus Colace) also failed to show any significant benefit of one over the other. No serious adverse effects were reported from any of the interventions. REVIEWER'S CONCLUSIONS: Trials to date have been heterogeneous and of poor quality, making it difficult to offer any definitive recommendations on the effectiveness of cerumenolytics for the removal of symptomatic ear wax. Future trials should be of high methodological quality, have large sample sizes, and compare both oil-based and water-based solvents with placebo and/or no treatment.

Carbamide Peroxide↗
PubMed2006

Adefovir dipivoxil and pegylated interferon alfa-2a for the treatment of chronic hepatitis B: a systematic review and economic evaluation.

OBJECTIVES: To assess the clinical effectiveness and cost-effectiveness of adefovirdipivoxil (ADV) and pegylated interferon alfa-2a (PEG) for the treatment of adults with chronic hepatitis B infection (CHB). DATA SOURCES: Electronic databases for the period from 1995-6 to April 2005. Websites of the relevant organisations. REVIEW METHODS: Searches were made for studies of clinical effectiveness, cost-effectiveness, quality of life, resource use/costs and epidemiology/natural history. Randomised controlled trials (RCTs) were included that compared PEG and ADV with currently licensed treatments for CHB, including non-pegylated ('standard') interferon alfa (IFN), lamivudine (LAM), and best supportive care. The trials were reviewed in a narrative synthesis but meta-analysis was not undertaken owing to heterogeneity in the interventions and comparators evaluated. A model was developed to estimate the cost-effectiveness (cost-utility) of PEG and of ADV compared with IFN, LAM and best supportive care in a UK cohort of adults with CHB. The perspective of the cost-effectiveness analysis was that of the NHS and personal social services. A Markov state transition model was constructed, informed by a systematic search of the literature to identify source material on the natural history, epidemiology and treatment of CHB. Interventions were evaluated against their closest comparator (for PEG this is IFN, and for ADV this is LAM). In addition, the cost-effectiveness of sequential treatment scenarios was modelled. RESULTS: A total of 1086 references to clinical effectiveness studies were identified, of which seven fully published RCTs and one systematic review met the inclusion criteria. Four of the RCTs evaluated the effectiveness of ADV and three reported results for PEG. In addition, a conference abstract was included reporting interim results from an on-going Phase II RCT of ADV in combination with LAM. The published trials were of good quality, although details of randomisation and allocation of concealment were poorly reported. ADV was significantly more effective than placebo. Response rates were in the range 21-51% compared with 0%, respectively. For patients resistant to LAM, response rates were significantly higher for those treated with ADV in addition to on-going LAM (35-85%) than those who continued on LAM with placebo (0-11%). Significant alanine aminotransferase (ALT) reductions to normal levels were observed in all studies. For treatment-naive patients, seroconversion rates were 12-14% for ADV compared with 6% for placebo (statistically significant), rates were higher for LAM-resistant patients who received ADV in addition to on-going LAM (8%) than those who continued on LAM with placebo (2%) (no significance value was reported), and rates were higher for LAM-resistant patients who switched to ADV than those who continued on LAM with placebo (11 versus 0%, respectively; not statistically significant). HBsAg loss or seroconversion was observed in less than 5% of patients taking ADV. Two ADV studies reported changes in liver histology. In general, histological improvement and necroinflammatory activity/fibrosis scores were significantly better in ADV groups than in placebo groups. Dose discontinuations for safety reasons were low for patients receiving ADV. With the exception of headache, the most commonly reported adverse events were often seen in the placebo groups in similar proportions to the ADV groups, with different trials reporting conflicting results. PEG/LAM dual therapy and PEG monotherapy were similar in effect on HBV DNA and ALT levels, and both were significantly superior to LAM monotherapy. Response rates were higher for HBeAg-negative patients than for HBeAg-positive patients. HBeAg seroconversion rates at follow-up were significantly higher for PEG monotherapy patients than for those receiving either a combination of PEG and LAM or LAM monotherapy (32, 27 and 19%, respectively). For the comparison between PEG and IFN-2a, there was a significant difference in the combined outcome of ALT normalisation, HBV DNA response and HBeAg seroconversion at follow-up (24 versus 12%, respectively). Changes in liver histology were reported by two studies. There was no statistically significant difference in histological improvement between the PEG monotherapy groups, the LAM monotherapy groups and the dual therapy groups. Two PEG trials reported small percentages (up to 5%) of HBsAg loss or seroconversion among patients receiving PEG either as monotherapy or in combination with LAM, but no HBsAg loss or seroconversion was reported in those receiving LAM monotherapy. Health-related quality of life (HRQoL) scores, as measured by the Short Form with 36 Items, decreased during treatment, but returned to at least baseline levels at follow-up (based on unpublished data). For HBeAg-positive patients, there were no significant differences in scores between treatment groups. Dose discontinuations for safety reasons were significantly higher for patients receiving PEG than for patients receiving LAM monotherapy. The most commonly reported adverse events in the PEG studies were headache, pyrexia, fatigue, myalgia and alopecia. Only one fully published economic evaluation was identified, reporting a US cost-effectiveness study of ADV as salvage therapy for chronic hepatitis B with LAM resistance. A Markov model was used to estimate cost-effectiveness of interferon alfa (6-12 months), LAM and LAM followed by ADV when resistance occurs. ADV generated the most (undiscounted) life-years, but at highest costs, with an incremental cost-effectiveness ratio (ICER) of US$14,204 per life-year gained. Using our model, incremental cost per QALY estimates (baseline cohort of all patients) were: 5994 pounds for IFN compared with best supportive care, 6119 pounds for PEG compared with IFN, 3685 pounds for LAM compared with best supportive care, and 16,569 pounds for ADV compared with LAM. Incremental cost per QALY estimates (HBeAg-positive patients only) were: 7936 pounds for IFN (24 weeks) compared with best supportive care, 16,166 pounds for PEG (48 weeks) compared with IFN (24 weeks), 3489 pounds for LAM compared with best supportive care, and 15,289 pounds for ADV compared with LAM. Incremental cost per QALY estimates (HBeAg-negative patients only) were: 3922 pounds for IFN (48 weeks) compared with best supportive care, 2162 pounds for PEG (48 weeks) compared with IFN (24 weeks), 4131 pounds for LAM compared with best supportive care, and 18,620 pounds for ADV compared with LAM. For the sequential treatment strategies, incremental cost per QALY estimates ranged from 3604 pounds (IFN followed by LAM versus IFN alone) to 11,402 pounds (IFN followed by LAM with adefovir salvage versus IFN followed by LAM). In all of these cases, the ICERs are well within the range that would conventionally be regarded as being cost-effective. The probabilistic sensitivity analysis found that LAM is a cost-effective option at lower willingness-to-pay thresholds for health outcomes, but as the threshold is increased adefovir is increasingly likely to be the optimal intervention. Where a willingness-to-pay threshold of above 10,000 pounds per QALY is employed, PEG is highly likely to be the optimal intervention compared with IFN (based on a cohort of HBeAg-positive and -negative patients). Interferon alfa (non-pegylated or pegylated) followed by LAM would be the optimal strategy at lower willingness-to-pay thresholds. As the threshold increases, the sequential treatment strategy of PEG followed by LAM with adefovir added as salvage therapy is increasingly likely to be the optimal intervention. CONCLUSIONS: ADV and PEG are associated with significant improvements in a number of biochemical, virological and histological outcomes in both HBeAg-positive and -negative patients. For a small proportion of patients this is associated with resolution of infection. For another proportion it leads to remission and a reduced risk of progressing to cirrhosis, hepatocellular carcinoma, liver transplant and death. For others who do not respond or who relapse, retreatment with another agent is necessary. The results of our cost-effectiveness analysis demonstrate that incremental costs per QALY for a range of comparisons were between 5994 pounds and 16,569 pounds and within the range considered by NHS decision-makers to represent good value for money. When subjected to sensitivity analysis, most costs per QALY estimates remained under 30,000 pounds. Further RCT evidence of the effectiveness of anti-viral treatment is required, particularly for subgroups of patients with different genotypes, patients with cirrhosis, patients from different ethnic groups, patients with co-infections (e.g. HIV, HCV) and co-morbidities, liver transplant patients and children and adolescents.

Adenine↗
PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗