Clinical effectiveness and cost-effectiveness of different models of managing long-term oral anticoagulation therapy: a systematic review and economic modelling

OBJECTIVES

To examine the clinical effectiveness and cost-effectiveness of self-testing and self-management of oral anticoagulation treatment compared with clinic-based monitoring.

DATA SOURCES

Major electronic databases were searched up to September 2005.

REVIEW METHODS

A systematic review was undertaken of relevant data from selected studies. Results about complication events and deaths were pooled in meta-analyses using risk difference (RD) as the outcome statistic. Heterogeneity across trials and possible publication bias were statistically measured. Subgroup analyses (post hoc) were conducted to compare results of self-testing versus self-management, low versus high trial quality, trials conducted in the UK versus trials in other countries and industry versus other sponsors. A Markov-type, state-transition model was developed. Stochastic simulations using the model were conducted to investigate uncertainty in estimated model parameters.

RESULTS

In the 16 randomised and eight non-randomised trials selected, patient self-monitoring of oral anticoagulation therapy was found to be more effective than poor-quality usual care provided by family doctors and as effective as good-quality specialised anticoagulation clinics in maintaining the quality of anticoagulation therapy. There was no significant RD of major bleeding events between patient self-monitoring and usual care controls and pooled analyses found that compared with primary care or anticoagulation control (AC) clinics, self-monitoring was statistically significantly associated with fewer thromboembolic events. However, the reduction in complication events and deaths was not consistently associated with the improvement of AC; in some trials this may be due to alternative explanations, including patient education and patient empowerment. Also, the improved AC and the reduction of major complications and deaths by patient self-monitoring were mainly observed in trials conducted outside the UK. According to UK-specific data, for every 100 eligible patients, 24% would agree to conduct self-monitoring, 17 of the 24 patients (70%) could be successfully trained and able to carry out self-monitoring and only 14 of these (80%) would conduct long-term self-monitoring. Seven cost-effectiveness studies were identified and the study that provided the most relevant UK data found that patient self-management was more expensive than current routine care (417 pounds versus 122 pounds per patient-year) and concluded that using a cost-effectiveness threshold of 30,000 pounds per quality-adjusted life-year (QALY) gained, patient self-management does not appear to be cost-effective. De novo modelling for this report found that the incremental cost per QALY gained by patient self-monitoring is 122,365 pounds over 5 years and 63,655 pounds over 10 years. The estimated probability that patient self-monitoring is cost-effective (up to 30,000 pounds/QALY) is 44% over a 10-year period. Wide adoption of patient self-monitoring of anticoagulation therapy would cost the NHS an estimated additional 8-14 million pounds per year.

CONCLUSIONS

For selected and successfully trained patients, self-monitoring is effective and safe for long-term oral anticoagulation therapy. In general, patient self-management (PSM) is unlikely to be more cost-effective than the current specialised anticoagulation clinics in the UK; self-monitoring may enhance the quality of life for some patients who are frequently away from home, who are in employment or education, or those who find it difficult to travel to clinics. Further research is needed into alternative dosing regimes, the clinical effectiveness and cost-effectiveness of patient education and training in long-term oral anticoagulation therapy, UK-relevant cost-effectiveness, the effectiveness of PSM in children, and the potential future developments of near-patient testing devices.

Adjusted indirect comparison may be less biased than direct comparison for evaluating new pharmaceutical interventions

OBJECTIVE

To investigate discrepancies between direct comparison and adjusted indirect comparison in meta-analyses of new versus conventional pharmaceutical interventions.

STUDY DESIGN AND SETTING

Results of direct comparison were compared with results of adjusted indirect comparison in three meta-analyses of new versus conventional drugs. The three case studies are (1) bupropion versus nicotine replacement therapy for smoking cessation, (2) risperidone versus haloperidol for schizophrenia, and (3) fluoxetine versus imipramine for depressive disorders.

RESULTS

In all the three cases, effects of new drugs estimated by head-to-head trials tend to be greater than that by adjusted indirect comparisons. The observed discrepancies could not be satisfactorily explained by the play of chance or by bias and heterogeneity in adjusted indirect comparison. This observation, along with analysis of possible systematic bias in the direct comparisons, suggested that the indirect method might have produced less biased results. Simulations found that adjusted indirect comparison may counterbalance bias under certain circumstances.

CONCLUSION

Adjusted indirect comparison could be used to cross-examine the validity and applicability of results from head-to-head randomized trials. The hypothesis that adjusted indirect comparison may provide less biased results than head-to-head randomized trials needs to be investigated by further research.

Clinical effectiveness and cost-effectiveness of bone morphogenetic proteins in the non-healing of fractures and spinal fusion: a systematic review

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of bone morphogenetic protein (BMP) for the treatment of spinal fusions and the healing of fractures compared with the current standards of care.

DATA SOURCES

Electronic databases, related journals and references from identified studies were searched in January 2006, with an updated search only for randomised controlled trials (RCTs) in November 2006.

REVIEW METHODS

A systematic review of available data was conducted. The data from selected studies were then analysed and graded according to quality and processed to give a value to the efficacy of BMP. Existing models were modified or updated to evaluate the cost-effectiveness of BMP for open tibial fractures and spinal fusion.

RESULTS

All selected trials were found to have several methodological weaknesses. Insufficient sample size in most trials, meant that patient baseline comparability between trial arms was not achieved and the statistical power to detect a moderate effect was low. Data did indicate that BMP increased fracture union among patients with acute tibial fractures and found that high-dose BMP is more effective than a lower dose for open tibial fractures. The healing rate in the BMP group was not found to be statistically significantly different from that in the autogenous bone grafting group for patients with tibial non-union fractures, but BMP reduced the number of secondary interventions in patients with acute tibial fractures compared with controls. There was very limited evidence that BMP in scaphoid non-union was safe and may help to accelerate non-union healing when used in conjunction with either autograft or allograft. There was evidence that BMP-2 is more effective than autogenous bone graft for radiographic fusion in patients with single-level degenerative disc disease. No significant difference was found when BMP-7 was compared with autograft for degenerative spondylolisthesis with spinal stenosis and spondylolysis. The use of BMP was associated with a reduced operating time, improvement in clinical outcomes and a shorter hospital stay as compared with autograft. The proportion of secondary interventions tended to be lower in the BMP group than the control, but not of statistical significance. Trial data on time to return to work postoperatively were sometimes difficult to interpret because of unclear or inappropriate data analysis methods. The incremental cost of BMP for open tibial fractures was estimated to be about 3.5 million pounds per year in the UK. The estimated incremental cost per quality-adjusted life-year (QALY) gained is 32,603 pounds. The probability that cost per QALY gained is less than 30,000 pounds for open tibial fracture is 35.5%. The cost-effectiveness ratio is sensitive to the price of BMP and the severity of open tibial fractures. The use of recombinant human bone morphogenetic protein for spinal fusion surgery may increase the cost to the UK NHS by about 1.3 million pounds per year. The estimated incremental cost per QALY gained was about 120,390 pounds. The probability that BMP is cost-effective (i.e. cost/QALY less than 30,000 pounds) was only 6.4%. From the societal perspective, the estimated total cost of using BMP for spinal fusion is about 4.2 million pounds per year in the UK.

CONCLUSIONS

Additional BMP treatment plus conventional intervention is more effective than conventional intervention alone for union of acute open tibial fractures. The cost-effectiveness of additional BMP may be improved if the price of BMP is reduced or if BMP is mainly used in severe cases. BMP may eliminate the need for autogenous bone grafting so that costs and complications related to harvesting autograft can be avoided. In non-unions, there is no evidence that BMP is more or less effective than bone graft; however, it is currently used when bone graft and other treatments have failed. The use of BMP-2 in spinal fusion surgery seems to be more effective than autogenous bone graft in terms of radiographic spinal fusion among patients with single-level degenerative disc disease. There is a lack of evidence about the effectiveness of BMP for other spinal disorders including spondylolisthesis and spinal stenosis. There was limited evidence showing that BMP is associated with greater improvement in clinical outcomes. According to the results of economic evaluation, the use of BMP for spinal fusion is unlikely to be cost-effective. The following areas would benefit from further research: clinical trials of BMP that include formal economic evaluation, a multicentre RCT of fracture non-union and of interbody and/or posterolateral spinal fusion, trials of non-tibial acute long bone fractures, and RCTs comparing BMP-2, BMP-7 and controls.

Identification of vip3A-type genes from Bacillus thuringiensis strains and characterization of a novel vip3A-type gene

AIMS

To search for novel Vip3A proteins for controlling insect pests.

METHODS AND RESULTS

A pair of universal primers was designed based on the conserved regions of five vip3A genes. Amplified products were digested with the HindIII and EcoR enzymes so as to confirm different restriction fragment length polymorphism (RFLP) patterns used to identify vip3A-type genes. The vip3A gene types of 606 Bacillus thuringiensis strains were screened and three patterns of RFLP were successfully identified. Two novel vip3A genes were found and one of these, vip3Aa19, was further characterized and its product was confirmed toxic to Spodoptera exigua, Helicoverpa armigera and Plutella xylostella larvae. Partial sequences of another novel vip3A-type gene were obtained that shared 83% homology with that of the vip3Af1 gene.

CONCLUSIONS

A polymerase chain reaction (PCR)-RFLP system we developed could be used for identifying novel vip3A-genes from B. thuringiensis strains. A novel Vip3A protein was found to have a broader insecticidal spectrum.

SIGNIFICANCE AND IMPACT OF THE STUDY

The reported method is a powerful tool to find novel Vip3A proteins from large-scale B. thuringiensis strains. The novel Vip3A protein may be used to control insect pests or resistant insect pests by constructing genetically engineered strains or transgenic plants.

Improving toxicity of Bacillus thuringiensis strain contains the cry8Ca gene specific to Anomala corpulenta larvae

The cry8C-type gene designated cry8Ca2, which was cloned and sequenced from a Bacillus thuringiensis isolate HBF-1 in China, consisted of an open reading frame of 3483 bp encoding a protein of 1160 amino-acid residues. Sequence analysis showed that the Cry8Ca2 protoxin of 130.5 kDa had 99.9% sequence homology with the previously reported Cry8Ca1 protein, with one mismatch between the two amino-acid sequences. When the Cry8Ca2 toxin was expressed in a crystal-negative strain of B. thuringiensis (HD-73(-)), elliptical crystals were produced. Cell extracts from this recombinant strain showed insecticidal activity against Anomala corpulenta larva. Mutant cry8Ca2 genes, produced by polymerase chain reaction amplification with Taq DNA polymerase, were used to develop recombinant B. thuringiensis strains. Mutants producing higher levels of insecticidal activity were identified by bioassay. Thirty-five mutants forming crystals were characterized, and two of them showed significantly increased insecticidal activity against A. corpulenta larva. The 50% lethality concentrations (LC(50)) of the two mutants were 0.2334 x 10(8) and 0.2591 x 10(8) colony-forming units g(-1), considerably lower than the LC(50) of the wild-type strain HBF-1 (0.9583 x 10(8) CFU g(-1)) and that of B. thuringiensis serovar japonensis strain Buibui (1.0752 x 10(8) CFU g(-1)).

Genetic associations in peripheral joint osteoarthritis and spinal degenerative disease: a systematic review

We conducted a systematic review of genetic association studies for osteoarthritis of the peripheral joints (OA) and spinal degenerative disease (SDD). Electronic searches were carried out for any English language article reporting on a gene association study for either OA or SDD published up until the end of 2006. A team of seven reviewers used a standardised template to extract data in duplicate. In all, 90 studies fulfilled our inclusion criteria, reporting a total of 94 significant associations from 83 different genes. We found relatively few instances in which a specific gene-disease association had been analysed by more than one study, and there were 14 cases in which significant associations were replicated in independent studies (at joints associated with the AGC1, ASPN, COL9A2, COL9A3, COL11A2, ESR1, FZRB, HFE, IL1A, IL1RN, PTGS2 and VDR genes).

METHOD

logical and reporting problems were widespread, including failure to report full results, missing population details, multiple testing, and over-reliance on subgroup analysis. In summary, the complex phenotypes of OA and SDD may have made it difficult for researchers to focus their efforts. The field is dominated by isolated analyses of disparate potential associations, a problem that is amplified by the frequent analysis of different polymorphisms within individual genes. Flaws in study methodology and interpretation undoubtedly increase the risk of publication bias. Closer adherence to published recommendations (in particular those produced by HuGENet) will help to ensure that future studies are well-designed and build on current understanding, rather than simply adding to the growing bank of potential associations.

Effect of vitamin A supplementation on immune function of well-nourished children suffering from vitamin A deficiency in China

OBJECTIVE

To clearly clarify the protective effect of vitamin A supplementation on immune function of well-nourished children suffering from vitamin A deficiency.

METHODS

Three hundred sixty-two children in two kindergartens in Wuhan China were enrolled. Detailed dietary assessment and anthropometry were undertaken to facilitate the exclusion of malnourished children. Seventy vitamin A-deficient children with informed consent were randomly divided into the vitamin A-deficient-supplemented group and vitamin A-deficient placebo group, 35 vitamin A-sufficient children (age- and sex-matched with the vitamin A-deficient-supplemented group children) were selected as vitamin A-sufficient placebo group. The baseline and follow-up level of selected immune parameters of the 105 children in three intervention groups were compared.

RESULTS

The total proportion of severe and marginal vitamin A-deficient children was 10.9 and 21.96%, respectively. At baseline, the serum complement C3 and sIgA level of vitamin A-sufficient children was significantly higher than that of vitamin A-deficient children (P < 0.05). However, the serum lysozyme level of vitamin A-sufficient children was inversely lower. After intervention, vitamin A-deficient-supplemented children increased serum vitamin A, complement C3 and sIgA level, but their serum lysozyme level inversely decreased.

CONCLUSIONS

Vitamin A deficiency was still a serious health problem in children in China cities. Vitamin A supplementation was efficacious in ameliorating serum vitamin A status and partially impaired immune function of well-nourished children suffering from vitamin A deficiency.

Ineffectiveness of rosiglitazone therapy in Nelson's syndrome

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists have been proposed as therapy to lower plasma ACTH in Cushing's disease. Cyclical secretion of ACTH may, however, explain some of the responses seen. Patients with Nelson's syndrome have persistently high levels of ACTH and may be a better model for examining new therapies to elevated ACTH levels.

OBJECTIVE

The objective of the study was to assess whether high-dose rosiglitazone therapy reduces circulating ACTH levels in Nelson's syndrome, a model of ACTH hypersecretion for which no established medical therapy exists.

DESIGN

The design was an open-label, prospective, nonrandomized study over 14 wk.

SETTING

The study was conducted at a university teaching hospital.

PATIENTS

Six patients with Nelson's syndrome participated in the study.

METHODS

Patients were assessed at -2, 0, 4, 8, and 12 wk. Rosiglitazone 12 mg/d was administered between 0 and 8 wk. PPAR-gamma immunoreactivity was assessed in pathological tissue.

OUTCOME MEASURE

Plasma ACTH was measured before (0830 h) and 120 min after morning dosing with hydrocortisone (HC).

RESULTS

One female withdrew prior to commencing therapy for personal reasons. There was no evidence that ACTH levels changed over time (P = 0.864). The average ACTH level was 1187 ng/liter (95% confidence interval 928-1446) for patients before the HC dose and 432 ng/liter (95% confidence interval 172-692) after the HC dose. PPAR-gamma immunoreactivity was positive in three ACTH-secreting tumors available.

CONCLUSIONS

Rosiglitazone 12 mg/d did not change circulating ACTH over time, despite PPAR-gamma receptor expression in the tumor tissue. However, this does not preclude the possibility that other patients may respond or that higher doses of rosiglitazone or more potent agonists might prove useful treatment.

A distinct role for PI3Kgamma in suppressing the development and progression of experimental autoimmune encephalomyelitis (EAE) (129.30)

Phosphoinositide 3-kinases (PI3K) are intracellular signaling proteins involved in cellular responses such as chemotaxis, proliferation and apoptosis. Selective inhibitors of the PI3Kγ-isoform have recently become available. This study explores the role of PI3Kγ in the development and progression of EAE. PI3Kγ +/+ (wt) and PI3Kγ −/− (ko) mice were immunized for EAE using myelin oligodendrocyte glycoprotein p35-55 (MOG) and assessed for clinical signs, CNS histopathology and T cell activation. WT mice showed a progressive disease course with elevations in inflammatory cytokines increased CNS mononuclear infiltrates. In contrast, ko mice exhibited a delayed onset and dramatically less severe EAE course characterized by decreased T cell activation and inflammatory cytokines (TNF-α, IFN-γ, IL-2, IL-12p40, IL-6, IL-17 and MCP-1). Male ko mice were significantly more protected than ko females. Adoptive transfer of MOG-activated T cells into ko recipients show that ko mice are resistant to passive disease induction. Interestingly, wt recipients of ko donors immunized for EAE were also protected. Furthermore, adoptive transfer of activated GFP+ T cells show marked decreased infiltration of GFP+ T cells into the CNS. Taken together, these findingssuggest that depletion of PI3Kγ results in a down-regulation of the inflammatoryresponse caused by impaired trafficking of cells critical to generation of the immune response.

(Supported by NIH grant AI 064320 and National MS Society Grant RG 3272).

A novel rice MAPK gene, OsBIMK2, is involved in disease-resistance responses

The mitogen-activated protein kinase (MAPK) cascades play important roles in transmission of extracellular signals to the downstream effector proteins through a mechanism of protein phosphorylation. In this study, we isolated and identified a novel rice MAPK gene, OSBIMK2 ( ORYZAE SATIVA L. BTH-Induced MAP Kinase 2). The OSBIMK2 encodes a 506 amino acid protein with molecular weight of 63 kD. The recombinant OSBIMK2 expressed in ESCHERICHIA COLI showed an autophosphorylation activity IN VITRO. OSBIMK2 is a single-copy gene in the rice genome. Expression of OSBIMK2 was activated upon treatment with benzothiadiazole (BTH), which is capable of inducing disease resistance in rice. Expression of OsBIMK2 was also up-regulated during early stage after inoculation with MAGNAPORTHE GRISEA in BTH-treated rice seedlings and during an incompatible interaction between M. GRISEA and a blast-resistant rice genotype. Over-expression of the rice OSBIMK2 gene in transgenic tobacco resulted in an enhanced disease resistance against tomato mosaic virus and a fungal pathogen, ALTERNARIA ALTERNATA. These results suggest that OSBIMK2 plays a role in disease resistance responses.

Temporomandibular joint synovial fibroblasts mediate serine proteinase dependent Type I collagen degradation

Degenerative temporomandibular joint (TMJ) disorders are characterized by the excessive turnover of collagen. In addition to the matrix metalloproteinase (MMP) and cathepsin mediated collagen degradation pathways, a serine proteinase dependent pathway has recently been identified in TMJ fibroblasts. This study focused on further characterizing this serine proteinase pathway utilizing a media-mediated collagen degradation assay and zymography. The conditioned media from cell-mediated collagen degradation assays were incubated with Type I collagen at pH 7.5 with or without a MMP inhibitor (1,10-phenanthroline), serine proteinase inhibitors (alpha1-antitrypsin and soybean trypsin inhibitor, STI), or cysteine proteinase inhibitors. The data showed that 1,10-phenanthroline and STI reduced the collagen cleavage by 12.33% and 47.78%, respectively. The cysteine proteinase inhibitors had no effect. The combination of alpha1-antitrypsin and 1,10-phenanthroline inhibited the cleavage by 79.22%, while STI and 1,10-phenanthroline together blocked the cleavage by 85.44%. Zymography identified a proteinase at approximate 22.5 kDa, which was more effectively blocked by serine proteinase inhibitors than by MMP or cysteine proteinase inhibitors. Reverse transcript-PCR and real-time PCR results demonstrated that TMJ cells did not express trypsinogen-2 mRNA, a collagen cleaving serine proteinase. This study demonstrated that TMJ fibroblasts can predominantly utilize a serine proteinase to mediate collagen degradation, which is not trypsinogen-2.

Radiation effects on the cosmetic outcomes of immediate and delayed autologous breast reconstruction: An argument about timing

OBJECTIVE

To conduct a systematic review to gather the available evidence on the optimum timing of the radiotherapy in relation to autologous breast reconstruction.

MATERIAL AND METHODS

The data was extracted from scientific databases, and a manual follow-up of references. The studies were selected which included at least 20 patients with any method of autologous breast reconstruction who were treated with adjuvant radiotherapy either before or after their reconstruction, and had addressed the effects of radiotherapy on the cosmetic outcome in their results. The principal outcome was cosmetic appearance. Secondary outcomes were immediate and delayed complications.

RESULTS

We could not find any randomised controlled trial on this topic. Ten studies were included, most were retrospective, heterogeneous in terms of control groups, radiation doses, follow-up duration, and outcome measurements. Two studies included no control groups, and four studies compared the outcomes of patients with radiotherapy either before (n=3) or after (n=1) autologous breast reconstruction. The overall incidence of complications was increased in patients with radiotherapy in three out of these four studies. Only four studies directly compared the outcomes of patients who received radiotherapy before with patients who received radiotherapy after autologous breast reconstruction and two out of these reported worse outcomes associated with post-reconstruction radiotherapy.

CONCLUSIONS

Despite the paucity of the published data, the current evidence suggests that the radiation has a deleterious effect on autologous flap reconstruction. Until better methods of radiation delivery can be devised to minimise the long term radiation sequelae in the irradiated tissue, delayed reconstruction seems to be a safe option in most of the cases. However, the findings from these studies should be interpreted with great caution before generalising from their results.

Indirect comparisons of competing interventions

OBJECTIVES

To survey the frequency of use of indirect comparisons in systematic reviews and evaluate the methods used in their analysis and interpretation. Also to identify alternative statistical approaches for the analysis of indirect comparisons, to assess the properties of different statistical methods used for performing indirect comparisons and to compare direct and indirect estimates of the same effects within reviews.

DATA SOURCES

Electronic databases.

REVIEW METHODS

The Database of Abstracts of Reviews of Effects (DARE) was searched for systematic reviews involving meta-analysis of randomised controlled trials (RCTs) that reported both direct and indirect comparisons, or indirect comparisons alone. A systematic review of MEDLINE and other databases was carried out to identify published methods for analysing indirect comparisons. Study designs were created using data from the International Stroke Trial. Random samples of patients receiving aspirin, heparin or placebo in 16 centres were used to create meta-analyses, with half of the trials comparing aspirin and placebo and half heparin and placebo. Methods for indirect comparisons were used to estimate the contrast between aspirin and heparin. The whole process was repeated 1000 times and the results were compared with direct comparisons and also theoretical results. Further detailed case studies comparing the results from both direct and indirect comparisons of the same effects were undertaken.

RESULTS

Of the reviews identified through DARE, 31/327 (9.5%) included indirect comparisons. A further five reviews including indirect comparisons were identified through electronic searching. Few reviews carried out a formal analysis and some based analysis on the naive addition of data from the treatment arms of interest. Few methodological papers were identified. Some valid approaches for aggregate data that could be applied using standard software were found: the adjusted indirect comparison, meta-regression and, for binary data only, multiple logistic regression (fixed effect models only). Simulation studies showed that the naive method is liable to bias and also produces over-precise answers. Several methods provide correct answers if strong but unverifiable assumptions are fulfilled. Four times as many similarly sized trials are needed for the indirect approach to have the same power as directly randomised comparisons. Detailed case studies comparing direct and indirect comparisons of the same effect show considerable statistical discrepancies, but the direction of such discrepancy is unpredictable.

CONCLUSIONS

Direct evidence from good-quality RCTs should be used wherever possible. Without this evidence, it may be necessary to look for indirect comparisons from RCTs. However, the results may be susceptible to bias. When making indirect comparisons within a systematic review, an adjusted indirect comparison method should ideally be used employing the random effects model. If both direct and indirect comparisons are possible within a review, it is recommended that these be done separately before considering whether to pool data. There is a need to evaluate methods for the analysis of indirect comparisons for continuous data and for empirical research into how different methods of indirect comparison perform in cases where there is a large treatment effect. Further study is needed into when it is appropriate to look at indirect comparisons and when to combine both direct and indirect comparisons. Research into how evidence from indirect comparisons compares to that from non-randomised studies may also be warranted. Investigations using individual patient data from a meta-analysis of several RCTs using different protocols and an evaluation of the impact of choosing different binary effect measures for the inverse variance method would also be useful.

Imatinib for the treatment of patients with unresectable and/or metastatic gastrointestinal stromal tumours: systematic review and economic evaluation

OBJECTIVES

To assess the clinical and cost-effectiveness of imatinib in the treatment of unresectable and/or metastatic, KIT-positive, gastrointestinal stromal tumours (GISTs), relative to current standard treatments.

DATA SOURCES

Electronic databases.

REVIEW METHODS

As there were no randomised trials that have directly compared imatinib with the current standard treatment in patients with advanced GIST, this review included non-randomised controlled studies, cohort studies, and case series that reported effectiveness results of treatment with imatinib and/or other interventions in patients with advanced GIST. The effectiveness assessment was based on the comparison of results from imatinib trials and results from studies of historical control patients. Economic evaluation was mainly based on an assessment and modification (when judged necessary) of a model submitted by Novartis.

RESULTS

Evidence from published uncontrolled trials involving 187 patients, and from abstracts reporting similar uncontrolled trials involving 1700 patients, indicates that approximately 50% of imatinib-treated individuals with advanced GIST experience a dramatic clinical response in terms of at least a 50% reduction in tumour mass. At present, although useful data are accumulating, it is not possible to predict which patients may respond in this way. Fifteen studies where possible GIST patients had been treated with therapies other than imatinib or best supportive care were also identified. All imatinib-treated patients experienced adverse effects, although they were relatively mild. Overall, imatinib was reported to be well tolerated. The most common serious events included unspecified haemorrhage and neutropenia. Skin rash, oedema and periorbital oedema were the common adverse events observed. Patients on the highest dose regimen (1000 mg per day in one trial) may experience dose-limiting drug toxicity. A structured assessment was carried out of the Novartis economic evaluation of imatinib for unresectable and/or metastatic GIST. The model was clearly presented and well written, its structure and input data were transparent, and the level of simplification was reasonable in terms of the objectives and data availability. However, the original Novartis model overestimated the cost-effectiveness of imatinib because of disproportion of survival and time-to-treatment failure in the imatinib arm, and the use of a possibly biased survival curve for patients in the control arm. The original Novartis model was modified to correct these two important shortcomings, which made it less sensitive to the choice of the survival curve for the control patients. According to the modified Novartis model, the estimated cost per quality-adjusted life-year (QALY) was 85,224 UK pounds (range 51,515--98,889 UK pounds) after 2 years, 41,219 UK pounds (27,331--44,236 UK pounds) after 5 years and 29,789 UK pounds (21,404--33,976 UK pounds) after 10 years. The results from a new Birmingham model were also within the range of estimates from the modified Novartis model.

CONCLUSIONS

Evidence from uncontrolled studies indicates that the treatment with imatinib brings about clinically significant shrinkage of tumour mass in about half of patients with unresectable and/or metastatic, KIT-positive GIST. Results of modelling based on data from uncontrolled studies suggest that imatinib treatment improves survival in patients with unresectable and/or metastatic GIST. The economic evaluation modelling suggests that the cost per QALY gained ranges from 51,515 to 98,889 UK pounds after 2 years, from 27,331 to 44,236 UK pounds after 5 years, and from 21,404 to 33,976 UK pounds after 10 years. Further research is needed into quality of life within trials involving patients with advanced malignancy, and long-term follow-up of adverse events is needed. Subgroup analysis of which, if any, patient types have a better or worse response to imatinib is also required. Analysis of individual patient data may be a good way of exploring these issues. There are many uncertainties surrounding imatinib prescription, such as the length of time patients should be on imatinib, the dose, drug resistance and the optimum time-point in the disease course at which to give the drug. Secondary research such as an update of this systematic review and a reassessment of the model is highly recommended when ongoing trials reach completion.

Up-regulation of OsBIHD1, a rice gene encoding BELL homeodomain transcriptional factor, in disease resistance responses

In the present study, we cloned and identified a full-length cDNA of a rice gene, OsBIHD1, encoding a homeodomain type transcriptional factor. OsBIHD1 is predicted to encode a 642 amino acid protein and the deduced protein sequence of OsBIHD1 contains all conserved domains, a homeodomain, a BELL domain, a SKY box, and a VSLTLGL box, which are characteristics of the BELL type homedomain proteins. The recombinant OsBIHD1 protein expressed in Escherichia coli bound to the TGTCA motif that is the characteristic cis-element DNA sequence of the homeodomain transcriptional factors. Subcellular localization analysis revealed that the OsBIHD1 protein localized in the nucleus of the plant cells. The OsBIHD1 gene was mapped to chromosome 3 of the rice genome and is a single-copy gene with four exons and three introns. Northern blot analysis showed that expression of OsBIHD1 was activated upon treatment with benzothiadiazole (BTH), which is capable of inducing disease resistance. Expression of OsBIHD1 was also up-regulated rapidly during the first 6 h after inoculation with Magnaporthe grisea in BTH-treated rice seedlings and during the incompatible interaction between M. grisea and a resistant genotype. These results suggest that OsBIHD1 is a BELL type of homeodomain transcription factor present in the nucleus, whose induction is associated with resistance response in rice.

Novel nonmatrix-metalloproteinase-mediated collagen degradation

Matrix metalloproteinases (MMPs) and their inhibitors have long been believed to play a major role in the collagen loss seen in destructive temporomandibular joint (TMJ) disorders. This project was originally designed to examine the expression of MMPs and the tissue inhibitors of MMPs (TIMPs) by diseased human TMJ synovial fibroblasts and to determine their ability to degrade Type I collagen. Reverse transcriptase-PCR indicated that these TMJ synovial fibroblasts expressed mRNA for multiple MMPs and TIMPs. The collagen degradation assay showed that these TMJ synovial fibroblasts at passage 3 to 8 were capable of digesting the collagen underneath them on collagen-coated plates. This degradation was inhibited by GM6001, a synthetic MMP inhibitor. During passage 8 to 13, these TMJ fibroblasts were able to digest all the collagen in the wells. This degradation was completely inhibited by combining GM6001 and soybean trypsin inhibitor (STI), a serine proteinase inhibitor. The collagen cleavage activity of collected conditioned media was dramatically inhibited by STI but not by 1,10-phenanthroline, an MMP inhibitor. The data suggest that these TMJ cells utilize a MMP-dependent pathway and a novel MMP-independent pathway to digest Type I collagen.

Experimental studies of the material properties of the forewing of cicada(Homóptera, Cicàdidae)

Detailed investigations on the structural and mechanical properties of the forewing of the cicada were carried out. Measurement of the structures of the wings showed that the thickness of the membrane of each cell and the diameter of each vein were non-uniform in both the longitudinal and transverse directions, and their means were approximately 12.2 and 133.3 μm,respectively. However, the aspect ratios of the wings and the bodies were quite uniform and were approximately equal to 2.98 and 2.13, respectively. Based on the measured thickness, mass and area of the membranes of the cells,the mean density and the mean area density of the wing were approximately 2.3 g cm-3 and 2.8×10-3 g cm-2,respectively. In addition, the diameters of the veins of the wings, including the diameters of the holes in the vein of the leading edge, were examined. The mechanical properties of the wing were investigated separately by nanoindentation and tensile testing. The results indicated that the mean Young's modulus, hardness and yield stress of the membranes of the wings were approximately 3.7 GPa, 0.2 GPa and 29 MPa, respectively, and the mean Young's modulus and strength of the veins along the direction of the venation of wings were approximately 1.9 GPa and 52 MPa, respectively. Finally, the relevant results were briefly analyzed and discussed, providing a guideline to the biomimetic design of the aerofoil materials of micro air vehicles.

Effectiveness and cost-effectiveness of double reading of mammograms in breast cancer screening: findings of a systematic review

There is a lack of direct evidence on the effectiveness of double reading of breast screening mammograms within the context of national screening programmes even though about half of the countries that use mammography screening have implemented double reading. A systematic review was conducted to compare double reading with single reading of mammograms for screening accuracy, patient outcomes and costs. We searched an extensive range of electronic databases, bibliographies of studies were scanned and experts were contacted. Data extraction and quality assessment was undertaken independently by two reviewers. Estimates of the diagnostic accuracy were calculated for those studies with follow-up to identify interval cancers. Only 10 cohort studies met the inclusion criteria with reported extractable data on the effectiveness of double compared to single reading. The mix of methodologies meant that few conclusions could be drawn about the effect of double reading independent of number of views, or effects on size and type of tumours detected. Overall, double reading increases the cancer detection rate by 3-11 per 10,000 women screened and has a double impact on recall rates depending on the recall policy used. The benefit could be mainly in the detection of small cancers, and could be greatest where two readers have different strengths and weaknesses, or where readers are less experienced. Double reading can improve accuracy as compared with single reading. In particular, double reading by consensus or arbitration achieves an increase in cancer detection rate together with a reduction in the rate of women recalled for assessment. Further research should quantify the relative benefit from double reading according to recall policy and number of mammographic views, and estimate the impact on patient outcome.

Evaluating non-randomised intervention studies

OBJECTIVES

To consider methods and related evidence for evaluating bias in non-randomised intervention studies.

DATA SOURCES

Systematic reviews and methodological papers were identified from a search of electronic databases; handsearches of key medical journals and contact with experts working in the field. New empirical studies were conducted using data from two large randomised clinical trials.

METHODS

Three systematic reviews and new empirical investigations were conducted. The reviews considered, in regard to non-randomised studies, (1) the existing evidence of bias, (2) the content of quality assessment tools, (3) the ways that study quality has been assessed and addressed. (4) The empirical investigations were conducted generating non-randomised studies from two large, multicentre randomised controlled trials (RCTs) and selectively resampling trial participants according to allocated treatment, centre and period.

RESULTS

In the systematic reviews, eight studies compared results of randomised and non-randomised studies across multiple interventions using meta-epidemiological techniques. A total of 194 tools were identified that could be or had been used to assess non-randomised studies. Sixty tools covered at least five of six pre-specified internal validity domains. Fourteen tools covered three of four core items of particular importance for non-randomised studies. Six tools were thought suitable for use in systematic reviews. Of 511 systematic reviews that included non-randomised studies, only 169 (33%) assessed study quality. Sixty-nine reviews investigated the impact of quality on study results in a quantitative manner. The new empirical studies estimated the bias associated with non-random allocation and found that the bias could lead to consistent over- or underestimations of treatment effects, also the bias increased variation in results for both historical and concurrent controls, owing to haphazard differences in case-mix between groups. The biases were large enough to lead studies falsely to conclude significant findings of benefit or harm. Four strategies for case-mix adjustment were evaluated: none adequately adjusted for bias in historically and concurrently controlled studies. Logistic regression on average increased bias. Propensity score methods performed better, but were not satisfactory in most situations. Detailed investigation revealed that adequate adjustment can only be achieved in the unrealistic situation when selection depends on a single factor.

CONCLUSIONS

Results of non-randomised studies sometimes, but not always, differ from results of randomised studies of the same intervention. Non-randomised studies may still give seriously misleading results when treated and control groups appear similar in key prognostic factors. Standard methods of case-mix adjustment do not guarantee removal of bias. Residual confounding may be high even when good prognostic data are available, and in some situations adjusted results may appear more biased than unadjusted results. Although many quality assessment tools exist and have been used for appraising non-randomised studies, most omit key quality domains. Healthcare policies based upon non-randomised studies or systematic reviews of non-randomised studies may need re-evaluation if the uncertainty in the true evidence base was not fully appreciated when policies were made. The inability of case-mix adjustment methods to compensate for selection bias and our inability to identify non-randomised studies that are free of selection bias indicate that non-randomised studies should only be undertaken when RCTs are infeasible or unethical. Recommendations for further research include: applying the resampling methodology in other clinical areas to ascertain whether the biases described are typical; developing or refining existing quality assessment tools for non-randomised studies; investigating how quality assessments of non-randomised studies can be incorporated into reviews and the implications of individual quality features for interpretation of a review's results; examination of the reasons for the apparent failure of case-mix adjustment methods; and further evaluation of the role of the propensity score.

Structural and mechanical properties of the organic matrix layers of nacre

The type of nanostructure referred to in biomineralization as a mineral bridge has been directly observed and measured in the organic matrix layers of nacre by transmission electron microscopy and scanning electron microscopy. Statistical analysis provides the geometric characteristics and a distribution law of the mineral bridges in the organic matrix layers. Experiments reveal that the nanostructures significantly influences the mechanical properties of the organic matrix layers. In addition, the mechanical analysis illustrates the effects of the nanostructures on the behaviors of the organic matrix layers, and the analytical results explain the corresponding experimental phenomena fairly well. The present study shows that the mineral bridges play a key role in the mechanical performances of the organic matrix layers of nacre. The results obtained provide a guide to the interfacial design of synthetic materials.

A systematic review of tegaserod for the treatment of irritable bowel syndrome

AIM

To assess the clinical effectiveness of tegaserod for the treatment of irritable bowel syndrome (IBS).

DESIGN

Systematic review.

SETTING

Six placebo-controlled, randomized controlled trials (RCTs) retrieved from electronic searches (Medline, Embase, FDA website) and hand-searching.

MAIN OUTCOME MEASURES

Any outcome was accepted.

RESULTS

In a small pharmacodynamic study, tegaserod 4 mg/day accelerated orocecal transit compared with placebo, but did not affect gastric emptying rate and colonic transit. Five placebo-controlled studies evaluated Subject's Global Assessment of gastrointestinal (GI) symptoms in predominantly female patients who fulfilled Rome criteria for constipation-predominant IBS. Responder rates were higher with tegaserod 1-24 mg/day than with placebo, although it was not possible in this review to evaluate the consistency of this effect, to fully quantify the effect size, or identify patients who may gain most benefit from this treatment.

CONCLUSION

Currently published data on tegaserod for IBS are limited (two of six RCTs published in full, four as abstracts). Tegaserod may be an appropriate treatment for occasional use for relief of GI symptoms associated with constipation-predominant IBS. Further research, comparing tegaserod with alternative treatments for GI symptoms of IBS, should help define the place of this drug in therapy.

HLA-DR and DQ polymorphisms in bullous pemphigoid from northern China

Bullous pemphigoid (BP) is an autoimmune disease mediated by autoantibodies against hemidesmosome components. This study used PCR-sequence-specific primers to genotype polymorphisms in HLA-DR and DQ in 25 BP patients and 57 normal controls from northern China. We found lower frequencies of DRB1*08 (DR8) and DRB1*08/DQB1*06 (DR8/DQ6) haplotypes in BP patients than in controls (4.08% vs. 15.19% and 1.54% vs. 13.82%, respectively; P < 0.05), suggesting a protective role for DR8 and DR8/DQ6 haplotypes in BP patients from northern China; there were no statistical differences among other alleles tested. This result is strikingly different from previous reports that DQB1*0301 is associated with BP in Caucasian patients and DRB1*1101, DQB1*0302, DRB1*04/DQA1*0301/DQB1*0302 and DRB1*1101/ DQA1*0505/DQB1*0302 with Japanese BP patients. Ethnic differences in the polymorphic composition of the HLA-DR and DQ genes may influence genetic susceptibility to BP.

Activity of nitric oxide is dependent on, but is partially required for function of, salicylic acid in the signaling pathway in tobacco systemic acquired resistance

When tobacco plants were treated by injection with nitric oxide (NO)-releasing compounds, the sizes of lesions caused by Tobacco mosaic virus (TMV) on the treated leaves and on upper nontreated leaves were significantly reduced. The reduction in TMV lesion size was caused by NO released from the NO-releasing compounds; the byproduct formed after release of NO from the NO-releasing compound NOC-18, diethylenetriamine, did not itself alter lesion size. Treatment of tobacco plants with inhibitors of nitric oxide synthase or an NO scavenger attenuated but did not abolish the systemic acquired resistance (SAR) induced by salicylic acid (SA). In NahG transgenic tobacco plants, NO had no effect on lesion size following TMV infection. These results are consistent with the hypothesis that NO plays an important role in SAR induction in tobacco and that NO is required for the full function of SA as an SAR inducer. The activity of NO is fully dependent on the function of SA in the SAR signaling pathway in tobacco.

Molecular adaptations in islets from neonatal rats reared artificially on a high carbohydrate milk formula

Four day-old rat pups artificially raised on a high carbohydrate (HC) milk formula during their suckling period immediately develop hyperinsulinemia which persists into adulthood despite weaning onto lab chow on day 24. The present study investigates the molecular adaptations in islets isolated from neonatal rats in response to this dietary treatment during their suckling period. There is a significant increase in the level of preproinsulin mRNA and insulin biosynthesis in 12 day-old HC islets compared to islets from age-matched mother-fed (MF) control rats. Pancreatic duodenal homeobox factor-1 (PDX-1) modulates pancreatic ontogeny as well as preproinsulin gene expression in islets from neonatal rats. The mRNA level, DNA binding activity and protein content of PDX-1 are significantly increased in HC islets. The stress-activated protein kinase-2 and phosphatidylinositol 3-kinase have been reported to modulate PDX-1 activity in islets. The mRNA levels of these kinases are increased in HC islets. The mRNA level of upstream stimulatory factor (a modulator of PDX-1 gene expression) is also significantly increased in HC islets. These results indicate that the upregulation of several molecular events, including increases in the gene expression of preproinsulin, transcription factors and kinases may contribute to the chronic hyperinsulinemic state in the HC rats.

The role of the gut lymphoid tissue in induction of oral tolerance

The gut-associated lymphoid tissue (GALT) maintains a balance between immunological tolerance to dietary proteins and induction of active immune responses to pathogenic microorganisms. The oral administration of soluble protein antigens induces a state of systemic immunological unresponsiveness specific to the fed protein, termed oral tolerance. The two major mechanisms to explain oral tolerance are anergy/deletion of autoreactive lymphocytes and active suppression. This review will discuss the mechanisms of therapeutic oral tolerance in relation to events occurring at the site of antigen entry.

Use of a cDNA array for the identification of genes induced in islets of suckling rats by a high-carbohydrate nutritional intervention

Four-day-old rat pups that are raised artificially on a high-carbohydrate (HC) milk formula immediately develop hyperinsulinemia, which persists into adulthood without any further nutritional stimulus. cDNA array analysis was used to identify large-scale changes in gene expression patterns in islets from 12- and 100-day-old HC rats in response to the HC dietary modification during the suckling period. It was observed that the expression of several genes that belong to clusters involved in beta-cell development and/or beta-cell function was significantly upregulated in islets from 12- and 100-day-old HC rats. It is inferred that in addition to predicted changes in gene expression, for example preproinsulin gene, global changes in gene expression contribute to the hyperinsulinemic state in the HC rat.

Thirty-six cases of hyperglycemia treated by promoting blood circulation to remove stasis

Thirty-six cases with hyperglycemia were treated with the method of promoting blood circulation and removing stasis in a course of 4 weeks. The treatment was significantly effective in correcting the abnormal viscosity of the blood by reducing the contents of total plasmic cholesterol (TC), triglyceride (TG) and apoprotein B (apoB), while the level of the apoprotein A (apoA) was elevated.

Accuracy of outpatient endometrial biopsy in the diagnosis of endometrial hyperplasia

BACKGROUND

To determine the accuracy of outpatient endometrial biopsy in diagnosing endometrial hyperplasia in women with abnormal uterine bleeding.

DESIGN

Systematic quantitative review of published medical literature.

DATA SOURCES

Relevant papers were identified through electronic scanning of MEDLINE (1980-1999) and EMBASE (1980-1999), manual searching of bibliography of known primary and review articles and contact with manufacturers.

REVIEW METHODS

Studies were selected if accuracy of outpatient endometrial biopsy, in women with abnormal pre or postmenopausal uterine bleeding, was estimated compared to a reference standard, which was endometrial histology obtained by tissue sampling under anesthesia. Quality assessment and data extraction were performed in duplicate. Diagnostic accuracy was determined by pooled likelihood ratios (LR) for positive and negative test results for endometrial hyperplasia.

RESULTS

There were 881 subjects in 8 diagnostic evaluations reported in 6 primary studies. Postmenopausal women represented 25% of the participants studied. There were 43 patients in whom outpatient sampling was inadequate. A positive test result on outpatient biopsy diagnosed endometrial hyperplasia with a pooled LR of 12.0 (95% CI 7.8-18.6) while a negative test result had a pooled LR of 0.2 (95% CI 0.1-0.3). With a positive test result, the posttest probability of endometrial hyperplasia was 57.7% (95% CI 41.1%-72.7%) while it was 2.2% (95% CI 0.9%-4.1%) with a negative test.

CONCLUSION

Outpatient endometrial biopsy has modest accuracy in diagnosing endometrial hyperplasia. Therefore, additional endometrial assessment should be undertaken, especially if symptoms persist or intrauterine structural abnormalities are suspected.

Programming into adulthood of islet adaptations induced by early nutritional intervention in the rat

To investigate the influence of a high carbohydrate (HC) intake during the suckling period on pancreatic function in adult life, neonatal rats were artificially reared on a HC milk formula during the preweaning period and then weaned onto lab chow. In the adult HC rat, hyperinsulinemia is sustained by a variety of biochemical and molecular adaptations induced in the HC islets during the suckling period. The adult HC islets showed a distinct left shift in the glucose-stimulated insulin-secretory pattern. HC islets were also able to secrete moderate levels of insulin in the absence of glucose and in the presence of Ca(2+) channel inhibitors. In addition, the mRNA levels of preproinsulin, somatostatin transcription factor-1, upstream stimulatory factor-1, stress-activated protein kinase-2, phosphatidylinositol kinase, and GLUT-2 genes were significantly increased in HC islets. These results show that consumption of a HC formula during the suckling period programs pancreatic islet function in adult rats, resulting in the maintenance of hyperinsulinemia in the postweaning period and eventually leading to the development of obesity in adult life.

DNA typing system for HLA-A2 alleles by polymerase chain reaction with sequence-specific primers

OBJECTIVE

To establish a PCR-SSP method for discriminating as many HLA-A*02 alleles, which could easily be introduced into a routine laboratory.

METHODS

In this study we typed HLA-A*02 polymorphisms by a sequence-specific primer (SSP) method, which involved round 1 and round 2 PCR reactions to detect 17 HLA-A*02 alleles (they are HLA-A*0201-0217 alleles) covering exon 2 and exon 3.

RESULTS

We have found that DNA sample concentration and purity were the most important variable in determining the quality of the result. For identifying correct band size, the size marker used was important. We noticed that different PCR machines performed differently. By this method, we detected 20 HLA-A*02 positive genomic DNA samples and found 4 kinds of HLA-A*02 alleles. They were HLA-A*0201, 0203, 0206 and 0210.

CONCLUSION

The HLA-A*02 PCR-SSP method was proven to be a reliable and easily applicable typing method. Our results suggest that the SSP described here provides an optimal HLA-A*02 typing technique that may be useful in selecting donor-recipient pairs in bone marrow transplantation between unrelated individuals.

Total synthesis of (-)-salicylihalamide A

[see structure]. A 16-step synthesis of the novel cytotoxin salicylihalamide A (1E) has been achieved in 3.3% overall yield using ring closing metathesis to generate the macrolide and addition of (1Z,3Z)-hexadienylcuprate (2), which was generated in situ from ethylcuprate and acetylene, to alkenyl isocyanate 3 to form the side chain.

Methods for exploring heterogeneity in meta-analysis

In meta-analysis, when the difference in results between studies is greater than would be expected by chance, one needs to investigate whether the observed variation in results across studies is associated with clinical and/or methodological differences between studies. This article reviews methods used in meta-analysis for exploring heterogeneity, including statistical tests for homogeneity, methods for visually displaying results of primary studies, methods for reducing heterogeneity, methods for investigating sources of heterogeneity, and identification of moderator variables or effect modifiers. The investigation of sources of heterogeneity in meta-analysis is by nature exploratory, and therefore its results should always be interpreted with caution. However, careful investigation of heterogeneity may provide an important second level of evidence that can be useful in suggesting direction of future research. Sometimes, it may provide clinically important results by indicating who might benefit more or less from a treatment or how an intervention should be applied.

Rapid depletion of peripheral antigen-specific T cells in TCR-transgenic mice after oral administration of myelin basic protein

In myelin basic protein (MBP)-specific TCR-transgenic (Tg) mice, peripheral T cells express the Valpha2.3/Vbeta8.2-Tg TCR, demonstrate vigorous proliferative responses to MBP in vitro, and can exhibit experimental autoimmune encephalomyelitis (EAE) within 5 days of pertussis toxin injection. We explored the effects of oral administration of MBP on the cellular trafficking of the MBP-specific TCR-Tg cells and the ability of oral MBP to protect Tg mice from EAE. Tg mice were fed MBP, OVA or vehicle and sacrificed at various times after feeding. An immediate and dramatic decrease in Valpha2.3/Vbeta8.2(+)-Tg cells was observed in the periphery within 1 h after feeding. By 3 days after feeding, the percentage of Tg cells increased to near control levels, but decreased again by 10 days. When MBP or vehicle-fed Tg mice were challenged for EAE at this point, disease was severe in the vehicle-fed mice and reduced in the MBP-fed mice over the 40-day observation period. In vitro studies revealed a biphasic pattern of MBP proliferative unresponsiveness and an induction of Th1 cytokines. Immunohistochemical staining showed that the number of Tg cells found in the intestinal lamina propria increased dramatically as the number of Tg cells in the periphery decreased. There was no apparent proliferation of Tg cells in the lamina propria, indicating that Tg cells trafficked there from the periphery. Taken together, these results suggest that T cell trafficking into the site of Ag deposition acts to protect the TCR-Tg mouse from EAE.

The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth

BACKGROUND

Removal of wisdom teeth is one of the most common surgical procedures performed in the UK. Little controversy surrounds the removal of impacted third molars when they are associated with pathological changes such as infection, non-restorable carious lesions, cysts, tumours, and destruction of adjacent teeth and bone. However, the justification for prophylactic removal of impacted third molars is less certain and has been debated for many years.

OBJECTIVES

To provide a summary of existing evidence on prophylactic removal of impacted wisdom teeth, in terms of the incidence of surgical complications associated with prophylactic removal, and the morbidity associated with retention.

METHODS

A systematic review of the research literature was undertaken. METHODS - DATA SOURCES: An existing review formed the basis of this report, and additional literature searches were undertaken, including searches of electronic databases (MEDLINE, 1984-99; EMBASE, 1984-99; Science Citation Index, Cochrane Controlled Trials Register, National Research Register; Database of Abstracts of Reviews of Effectiveness), paper sources (including Clinical Evidence), and web-based resources. Relevant organisations and professional bodies were contacted for further information.

METHODS - STUDY SELECTION

Studies were selected for inclusion if they met the following criteria: (1) design - randomised controlled trials (RCTs), literature reviews, or decision analyses; (2) participants - people with unerupted or impacted third molars, or those undergoing surgical removal of third molars either as prophylaxis or due to associated pathological changes; (3) reported outcomes - either the pathological changes associated with retention of third molars, or post-operative complications following extraction. There were no language restrictions on study selection. METHODS - DATA EXTRACTION AND SYNTHESIS: Data from included studies were extracted into structured tables and individual study validity was assessed against methodological checklists. Data were summarised descriptively. Decisions relating to study selection, data extraction and validity assessment were made by two independent reviewers, and disagreements were resolved by discussion. For non-English papers, translators were recruited to assist with study selection and data extraction.

RESULTS

Forty studies were included in the review: two RCTs, 34 literature reviews, and four decision analysis studies. One RCT in the UK focused on the effects of retained third molars on incisor crowding (predominantly a cosmetic problem) in patients who had previously undergone orthodontic treatment. The results of this trial suggested that the removal of third molars to prevent late incisor crowding cannot be justified. Another on-going RCT in Denmark compares the effects and costs of prophylactic removal of third molars with removal according to morbidity. So far, this trial has recruited 200 participants, and preliminary results indicate that watchful waiting may be a promising strategy. However, more data and longer follow-up of patients are needed to conclude which treatment strategy is the most cost-effective. It is also known that a trial is on-going in the USA but no results are available so far. The methodological quality of the literature reviews was generally poor, and none of the reviews was systematic. Conclusions from nine reviews on anterior crowding suggested that there was only a weak association between retention of third molars and crowding. Six out of 21 reviews with a more general scope also concluded that the prophylactic removal of third molars was unjustified. Twelve general reviews did not conclude with a clear message about the management of third molars. Three reviews suggested that prophylactic removal of third molars is appropriate, but these reviews were of poorer methodological quality than the majority of other reviews. Three out of four papers focusing on surgical management expressed

Metal ion adducts in the structural analysis of ginsenosides by electrospray ionization with multi-stage mass spectrometry

The effect of metal (Li+, Na+, K+, Ag+) cationization on collision-induced dissociation of ginsenosides was investigated by electrospray ionization mass spectrometry combined with multi-stage mass spectrometry (ESI-MS(n)). The fragments of sodiated and lithiated molecules give valuable structural information regarding the nature of the aglycone and the sequence and linkage information of sugar moieties. However, the number and relative abundances of fragment ions from lithiated ginsenosides are significantly greater than for the sodiated species. The K+ adducts undergo glycosidic cleavages and very limited cross-ring reactions. The silver ion adducts fragment mainly through glycosidic cleavages.