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Biomedical subjects

F Song

Publications and source records attributed to F Song.

At least 37 records · Page 2Linked to original sources
PubMed2001

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.

Ambulatory Care↗
PubMed2001

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.

Journal Article↗
PubMed2001

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.

Immunity, Innate↗
PubMed2001

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.

Animals↗
PubMed2001

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.

Data Interpretation, Statistical↗
PubMed2001

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.

Aging↗
PubMed2001

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.

Adult↗
PubMed2001

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.

Animals↗
PubMed2001

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.

Alleles↗
PubMed2000

Interception of Deaminatively Generated Benzyl Carbenium Ions by Acetone.

Essentially free benzyl carbenium ions were generated via protonation of phenyldiazomethane with benzoic acid in acetone. Interestingly, no proton transfer occurred below -20 degrees C. After protonation and dediazoniation of the diazoalkane at -20 degrees C, the solvent was found to intercept the deaminatively generated carbocations to yield initially the corresponding O-benzyl oxonium ion and benzyl benzoate. The onium ion, however, was labile under the reaction conditions, and decomposed into a cascade of products whose concentrations as a function of time were used to trace the reaction pathway. Thus, the O-benzyl oxonium ion reacted with benzoate ion to yield (2-benzyloxy)isopropyl benzoate; subsequent decomposition of this O-benzyl-O-benzoyl ketal produced 2,2-dibenzyloxypropane (a dibenzyl ketal), 2-benzyloxypropene, and benzyl alcohol. In a related study, benzyl cations were generated via thermolyses of N-benzyl-N-nitroso-O-benzoyl hydroxylamine at 0 and -70 degrees C. The product distributions were found to be temperature-dependent and different from that in the PhCHN(2) + PhCO(2)H case.

Journal Article↗
PubMed2000

Staphylococcal enterotoxin B stimulates expansion of autoreactive T cells that induce apoptosis in intestinal epithelial cells: regulation of autoreactive responses by IL-10.

T cell responses to self Ags and normal microbial flora are carefully regulated to prevent autoreactivity. Because IL-10-deficient mice develop colitis, and this response is triggered by luminal flora, we investigated whether IL-10 regulates the ability of microbial Ags to induce autoreactive T cells that could contribute to intestinal inflammation. T cells from wild-type mice were primed with staphylococcal enterotoxin B (SEB) in vitro, which induced an autoreactive proliferative response to syngeneic feeder cells. The cells were predominately CD3+ and CD4+. T cells from IL-10-deficient mice were constitutively autoreactive, and SEB priming enhanced this further. The autoreactive, proliferative response of T cells from wild-type mice was suppressed by IL-10 in the primary or secondary culture, and this effect was inhibited by neutralizing Abs to the IL-10R. To confirm that an autoreactive repertoire was expanded after SEB priming, we used CBA/J mice (Mls-1a) in which autoreactive T cells recognizing the endogenous viral superantigen are depleted (Vbeta6, 7, 8.1 TCR-bearing cells). However, SEB rescued these autoreactive T cell repertoires. Adding anti-MHC class II Ab blocked the autoreactive response. SEB-primed splenic or colonic T cells also induced apoptosis in syngeneic intestinal epithelial cells that was blocked significantly by IL-10. Thus, microbial Ags have the potential to abrogate self tolerance by stimulating autoreactive T cells that become cytolytic to target cells. IL-10 plays a protective role in maintaining self tolerance after microbial stimulation by preventing the activation of T cells that contribute to epithelial cell damage.

Animals↗
PubMed2000

Total syntheses of (+/-)-anchinopeptolide D and (+/-)-cycloanchinopeptolide D.

The first synthesis of (+/-)-anchinopeptolide D (4) has been accomplished in seven steps in 10% overall yield from octopamine hydrochloride (17), N-(Boc)glycine (16), and 5-amino-2-hydroxypentanoic acid (22). The key step is the aldol dimerization and hemiaminal formation of alpha-keto amide 26, which gives primarily protected anchinopeptolide D 27 under kinetically controlled conditions. Cycloanchinopeptolide D (31) has been prepared by the unprecedented head-to-head photodimerization of the two hydroxystyrylamides of 4 using the hydrophobic effect in water to force the two side chains into close proximity so that [2 + 2] cycloaddition is faster than trans to cis double bond isomerization. Coupling of amine 21 with pyroglutamic acid affords the naturally occurring tripeptide 35, which had been assigned glutamic acid structure 34.

Alkaloids↗
PubMed2000

Rapid identification of saponins in plant extracts by electrospray ionization multi-stage tandem mass spectrometry and liquid chromatography/tandem mass spectrometry.

Electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)) and liquid chromatography coupled with on-line mass spectrometry (LC/MS/MS) were applied to characterize saponins in crude extracts from Panax ginseng. The MS(n) data of the [M - H](-) ions of saponins can provide structural information on the sugar sequences of the saccharide chains and on the sapogins of saponins. By ESI-MS(n), non-isomeric saponins and isomeric saponins with different aglycones can be determined rapidly in plant extracts. LC/MS/MS is a good complementary analytical tool for determination of isomeric saponins. These approaches constitute powerful analytical tools for rapid screening and structural assignment of saponins in plant extracts.

Chromatography, Liquid↗
PubMed2000

Risperidone versus typical antipsychotic medication for schizophrenia.

BACKGROUND: The 'conventional' neuroleptic drugs, such as haloperidol and chlorpromazine, are frequently used as the first line treatment for people with schizophrenia. However, about 5-25% of these people show poor response to these treatments and side effects often makes compliance with the 'older generation' of drug treatment problematic. Although the efficacy of these medications with respect to 'positive' symptoms is well described, little evidence exists that 'conventional' antipsychotic treatment has any effect on the 'negative' symptoms of schizophrenia. Risperidone is one of the 'new generation' neuroleptic compounds. As well as its reputed tendency to cause fewer movement disorders it is claimed that risperidone may improve negative symptoms. OBJECTIVES: To evaluate the effectiveness of risperidone for schizophrenia in comparison to 'conventional' neuroleptic drugs. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1980-1997), Cochrane Schizophrenia Group's Register (1997), The Cochrane Library (1997, Issue1), EMBASE (1980-1997), MEDLINE (1966-1997), PsycLIT (1974-1997), and SCISEARCH (1997) were undertaken. References of all identified studies were searched for further trial citations. Pharmaceutical companies and authors of trials were contacted. SELECTION CRITERIA: All randomised trials comparing risperidone to any 'conventional' neuroleptic treatment for those with schizophrenia or other serious mental illnesses. DATA COLLECTION AND ANALYSIS: Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were also independently extracted. Sensitivity analyses on dose of risperidone, haloperidol and duration of illness were undertaken for the primary outcomes of clinical improvement, side effects (movement disorders) and acceptability of treatment. For homogeneous dichotomous data the odds ratio (OR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) were calculated on an intention-to-treat basis. MAIN RESULTS: Twelve short-term studies and two long term studies provided data on 3401 people. This review provides no evidence relating to the effect of risperidone on cognitive or social functioning, quality of life, employment status, discharge from hospital and relapse rates. Risperidone increases the odds of moderate clinical improvement (OR 0.65, CI 0.55-0.77, NNT 10, CI 7-16). It appears to have little or no additional effect on the positive and negative symptoms of schizophrenia but did have less tendency to cause movement disorders, largely in comparison with haloperidol (OR 0.43, CI 0.34-0.55, NNT 7, CI 5-10) for use of antiparkinsonian medication. Risperidone seems to be more acceptable to those with schizophrenia (OR 0.69 CI 0.57-0.83, NNT 15, CI 10-30, 30% baseline risk of dropping out). Those taking risperidone are also marginally less likely to experience somnolence (OR 0.78, CI 0. 61-0.99, NNT 22). Weight gain, however, is more likely with risperidone (OR 1.51 CI 1.14-2.00, NNT 13). Funnel plots show that smaller studies generally show greater benefit for risperidone than larger studies. A publication bias in favour of risperidone amongst the included studies may explain this effect. Sensitivity analyses on dose of risperidone (excluding those receiving 1 or 2 mg) did not materially change the results for the principal outcomes. Excluding data from those on higher doses of haloperidol (>10mg/day) does marginally change the results. Risperidone is less effective in achieving clinical improvement and preventing dropout but outcomes relating to movement disorders change little. REVIEWER'S CONCLUSIONS: Little can be concluded about the long term effects of risperidone and generalising results beyond a comparison with haloperidol would be imprudent. Risperidone may be more acceptable to those with schizophrenia and have marginal benefits in terms of limited clinical improvement and side

Antipsychotic Agents↗
PubMed2000

Beds, mattresses and cushions for pressure sore prevention and treatment.

OBJECTIVES: To assess the effectiveness of pressure relieving beds, mattresses and cushions (support surfaces) in the prevention and treatment of pressure sores. SEARCH STRATEGY: Searches of 19 databases, hand searching of journals, conference proceedings, and bibliographies. SELECTION CRITERIA: Randomised controlled trials evaluating support surfaces for the prevention or treatment of pressure sores. There was no restriction on articles based on language or publication status. DATA COLLECTION AND ANALYSIS: Data extraction and assessment of study quality was undertaken by two reviewers independently. Trials with similar patients, comparisons, and outcomes were pooled. Where pooling was inappropriate, trials are discussed in a narrative review. MAIN RESULTS PREVENTION: 29 RCTs of support surfaces for pressure sore prevention were identified. Some high specification foam mattresses were more effective than 'standard' hospital foam mattresses in moderate-high risk patients. Pressure relieving mattresses in the operating theatre reduced the incidence of pressure sores post-operatively. The relative merits of alternating and constant low pressure, and of the different alternating pressure devices are unclear. Seat cushions and simple, constant low-pressure devices have not been adequately evaluated. Limited evidence suggests that low air loss beds reduce the incidence of pressure sores in intensive care. TREATMENT: 6 RCTs of support surfaces for pressure sore treatment were identified. There is good evidence that air-fluidised and low air loss beds improve healing rates. Seat cushions have not been adequately evaluated. 2 RCTs evaluated surfaces for both prevention and treatment in the same trial. REVIEWER'S CONCLUSIONS: PREVENTION - There is good evidence of the effectiveness of high specification foam over standard hospital foam, and pressure relief in the operating theatre. Treatment - There is good evidence of the effectiveness of air-fluidised and low air loss devices as treatments. Overall, however, it is impossible to determine the most effective surface for either prevention or treatment.

Beds↗
PubMed2000

Indirect comparison in evaluating relative efficacy illustrated by antimicrobial prophylaxis in colorectal surgery.

This paper aims to explore the potential usefulness and limitations of indirect comparisons in evaluating the relative efficacy of interventions. From a systematic review of antimicrobial prophylaxis in colorectal surgery, we identified 11 sets of randomized trials that can be used to compare antibiotics both directly and indirectly. The discrepancy between the direct and the indirect comparison is defined as the absolute value of difference in log odds ratio. The adjusted indirect comparison has the advantages that the prognostic factors of participants in different trials can be partially taken into account and more uncertainty be incorporated into its result by providing a wider confidence interval. However, considerable discrepancies exist between the direct and the adjusted indirect comparisons. When there is no direct comparison, the adjusted indirect method may be used to obtain some evidence about the relative efficacy of competing interventions, although such indirect results should be interpreted with great caution. Further empirical and methodologic research is needed to explore the validity and generalizability of the adjusted indirect comparison for evaluating different interventions.

Antibiotic Prophylaxis↗