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Biomedical subjects

C Chapple

Publications and source records attributed to C Chapple.

At least 19 recordsLinked to original sources
PubMed2006

Overactive bladder: The importance of new guidance.

Overactive bladder (OAB) affects an estimated 49 million people in Europe, but only a minority receive appropriate treatment. Others are bothered by unacceptable levels of symptoms that severely impair their quality of life and represent a significant financial burden to themselves and to their healthcare providers. Recently updated guidelines from the International Consultation on Incontinence (ICI) and the European Association of Urology (EAU) take account of important new developments in the management of bladder problems in both primary and secondary care. However, local implementation of previous guidance has been variable, with many patients with OAB and other bladder problems failing to gain full benefit from current clinical and scientific understanding of these conditions. The recent expansion of the range of treatments available for OAB and stress urinary incontinence makes it especially important that physicians become aware of the differential diagnosis of these conditions - the questions they need to ask, and the investigations which will help determine the most appropriate course of action.

Algorithms↗
PubMed2006

Systematic review and evaluation of methods of assessing urinary incontinence.

OBJECTIVES: To identify and synthesise studies of diagnostic processes of urinary incontinence and to construct an economic model to examine the cost-effectiveness of simple, commonly used primary care tests. DATA SOURCES: The electronic databases MEDLINE (1966--2002), CINAHL (1982--2002) and EMBASE (1980--2002). REVIEW METHODS: Studies were selected and assessed using the Quality Assessment of Diagnostic Studies (QUADAS) tool. Studies that reported the results of applying the same diagnostic procedure using the same threshold value (cut-off) were pooled using a random effects meta-analysis model to produce pooled estimates of sensitivity, specificity and diagnostic odds ratio together with 95% confidence intervals. RESULTS: In total, 6009 papers were identified from the literature search, of which 129 were deemed relevant for inclusion in the review, and these papers compared two or more diagnostic techniques. The gold-standard diagnostic test for urinary incontinence with which each reference test was compared was multichannel urodynamics. In general, reporting in the primary studies was poor; there was a lack of literature in the key clinical areas and minimal literature dealing with diagnosis in men. Only a limited number of studies could be combined or synthesised, providing the following results when compared with multichannel urodynamics. A clinical history for diagnosing urodynamic stress incontinence (USI) in women was found to have a sensitivity of 0.92 and specificity of 0.56 and for detrusor overactivity (DO) a sensitivity of 0.61 and specificity of 0.87. For validated scales, question 3 of the Urogenital Distress Inventory was found to have a sensitivity of 0.88 and specificity of 0.60. Seven studies compared a pad test with multichannel urodynamics; however, four different pad tests were studied and therefore it was difficult to draw any conclusions about diagnostic accuracy. Of the four studies comparing urinary diary with multichannel urodynamics, only one presented data in a format that allowed sensitivity and specificity to be calculated. Their reported values of 0.88 and 0.83 suggest that a urinary diary may be effective in the diagnosis of DO in women. Examination of the incremental cost-effectiveness of three primary care tests used in addition to history found that the diary had the lowest cost-effectiveness ratio of between pound 35 and pound 77 per extra unit of effectiveness (or case diagnosed). Imaging by ultrasound to determine leakage was found to be effective in the diagnosis of USI in women, with a sensitivity of 0.94 and specificity of 0.83. CONCLUSIONS: This is the first systematic review of methods for diagnosing urinary incontinence. As reporting of the primary studies was poor, clinical interpretation was often difficult because few studies could be synthesised and conclusions made. The report found that a large proportion of women with USI can be correctly diagnosed in primary care from clinical history alone. On the basis of diagnosis the diary appears to be the most cost-effective of the three primary care tests (diary, pad test and validated scales) used in addition to clinical history. Ultrasound imaging may offer a valuable alternative to urodynamic investigation. The clinical stress test is effective in the diagnosis of USI. Adaptation of such a test so that it could be performed in primary care with a naturally filled bladder may prove clinically useful. If a patient is to undergo an invasive urodynamic procedure, multichannel urodynamics is likely to give the most accurate result in a secondary care setting. There is a dearth of literature on the diagnosis of urinary incontinence in men, with no studies meeting the study criteria for data extraction in the diagnosis of bladder outlet obstruction. There is a need for large-scale, high-quality primary studies evaluating the use of a number of diagnostic methods in a primary care setting to be undertaken so that the results of this systematic review can be verified or not. Such studies should include not only an assessment of clinical effectiveness, in this case diagnostic accuracy, but also an assessment of costs and quality of life/satisfaction to inform future health policy decisions. Studies carried out should be reported to a better standard. The recommendations of the Standards for Reporting Diagnostic Accuracy (STARD) initiative should be followed to ensure the accuracy and completeness of reporting design and results.

Diagnostic Tests, Routine↗
PubMed2005

Long-term open-label solifenacin treatment associated with persistence with therapy in patients with overactive bladder syndrome.

OBJECTIVE: To examine safety and tolerability findings as primary endpoints, and efficacy outcomes as secondary endpoints, of solifenacin treatment over a period of up to 1 year. Long-term efficacy in the treatment of overactive bladder (OAB) syndrome depends in part on the patient's persistence with pharmacologic therapy. Agents with a favourable therapeutic index supporting high levels of patient satisfaction and persistence are needed. METHODS: The present study was a 40-week open-label extension of two 12-week, placebo-controlled, double-blind studies of solifenacin treatment in patients with OAB. Patients who completed the 12-week studies were offered participation in the open-label extension study. All patients who entered the open-label extension study initially received solifenacin 5 mg daily for 4 weeks, after which a flexible dosing regimen allowed patients to individualise their treatment (5 mg or 10 mg) at each of the 3 study visits. Safety and tolerability assessments (the primary variable) included adverse event reporting. Efficacy data were collected from micturition diaries completed at weeks 16, 28, 40, and 52. RESULTS: Ninety-one percent (1637/1802) of patients who completed the two 12-week randomised studies chose to participate in the long-term open-label extension study. A total of 81% of patients completed 40 weeks of open-label treatment. Solifenacin treatment was safe and well tolerated, and rates of anticholinergic side effects were relatively low. Only 4.7% of patients discontinued treatment owing to adverse events. Improvements in major symptoms of OAB were noted for all patients for up to 52 weeks of treatment. In patients randomised to solifenacin in the double-blind studies, there were small incremental improvements in all efficacy parameters (reductions in episodes per 24 hours of urgency, reductions in frequency and urge incontinence, and increases in volume voided per micturition) over the course of the extension study. Efficacy was confirmed when outcomes were assessed as a function of total solifenacin exposure. Patient satisfaction with solifenacin tolerability (85%) and efficacy (74%) were high. These results indicate that long-term treatment with solifenacin was well tolerated and associated with improvements in efficacy parameters based on patient diary data recorded over the 12-month treatment period. Moreover, the high level of patient satisfaction reported appeared to correlate well with the quantified improvements in key symptoms demonstrated in this study. CONCLUSIONS: Long-term therapy with solifenacin resulted in a favourable tolerability profile, and was associated with improvements in efficacy parameters based on diary data recorded over a 12-month period. This balance of tolerability and efficacy with solifenacin was associated with excellent persistence with therapy. These results suggest that solifenacin may be useful for the long-term treatment of the chronic symptoms associated with OAB.

Constipation↗
PubMed2005

Nocturia: morbidity and management in adults.

Nocturia is an increasingly prevalent and bothersome urinary symptom associated with considerable impact and morbidity in later life. Nocturnal frequency is associated with a number of underlying pathologies, both related and unrelated to the lower urinary tract. Following careful assessment, diagnosis and management, the condition is amenable to amelioration, if not complete cure in the majority of cases. This paper outlines the epidemiology, underlying pathophysiology and diseases associated with nocturia and reviews current treatment strategies.

Adrenergic alpha-Antagonists↗
PubMed2001

The basis for drug treatment of the overactive bladder.

The normal bladder functions, storage and elimination of urine, are dependent on neural circuits in the brain and spinal cord that coordinate the activity of the detrusor and that of the smooth and striated muscles of the outflow region. Disturbances at different levels may cause the overactive bladder (OAB) syndrome, characterized by urge, frequency and urge incontinence. Knowledge about the mechanisms controlling both normal and abnormal micturition is mandatory for the detection of targets for pharmacological intervention. Such targets may be found in the central nervous system (CNS) or peripherally. Several CNS transmitters can modulate voiding, but few drugs with a defined CNS site of action have been demonstrated to be clinically useful. Traditionally, drugs for treatment o

Central Nervous System↗
PubMed2001

Elucidation of new structures in lignins of CAD- and COMT-deficient plants by NMR.

Studying lignin-biosynthetic-pathway mutants and transgenics provides insights into plant responses to perturbations of the lignification system, and enhances our understanding of normal lignification. When enzymes late in the pathway are downregulated, significant changes in the composition and structure of lignin may result. NMR spectroscopy provides powerful diagnostic tools for elucidating structures in the difficult lignin polymer, hinting at the chemical and biochemical changes that have occurred. COMT (caffeic acid O-methyl transferase) downregulation in poplar results in the incorporation of 5-hydroxyconiferyl alcohol into lignins via typical radical coupling reactions, but post-coupling quinone methide internal trapping reactions produce novel benzodioxane units in the lignin. CAD (cinnamyl alcohol dehydrogenase) downregulation results in the incorporation of the hydroxycinnamyl aldehyde monolignol precursors intimately into the polymer. Sinapyl aldehyde cross-couples 8-O-4 with both guaiacyl and syringyl units in the growing polymer, whereas coniferyl aldehyde cross-couples 8-O-4 only with syringyl units, reflecting simple chemical cross-coupling propensities. The incorporation of hydroxycinnamyl aldehyde and 5-hydroxyconiferyl alcohol monomers indicates that these monolignol intermediates are secreted to the cell wall for lignification. The recognition that novel units can incorporate into lignins portends significantly expanded opportunities for engineering the composition and consequent properties of lignin for improved utilization of valuable plant resources.

Alcohol Oxidoreductases↗
PubMed2001

AtMYB4: a transcription factor general in the battle against UV.

Mounting evidence indicates that members of the large family of plant MYB proteins are involved in the transcriptional regulation of an array of metabolic and developmental processes. Recently, the Arabidopsis thaliana MYB, AtMYB4, was shown to regulate the accumulation of the UV-protectant compound sinapoylmalate by repressing the transcription of the gene encoding the phenylpropanoid enzyme cinnamate 4-hydroxylase. AtMYB4 is thus a key regulator of phenylpropanoid pathway gene expression, and is the first example of a MYB protein that functions as a transcriptional repressor.

Arabidopsis↗
PubMed2001

The sng2 mutant of Arabidopsis is defective in the gene encoding the serine carboxypeptidase-like protein sinapoylglucose:choline sinapoyltransferase.

Serine carboxypeptidase-like (SCPL) proteins have traditionally been assigned roles in the hydrolytic processing of proteins; however, several SCPL proteins have recently been identified as catalysts in transacylation reactions of plant secondary metabolism. The novel functions of these enzymes suggest a catalytic diversity for plant SCPL proteins that extends beyond simple hydrolysis reactions. Characterization of the Arabidopsis sng2 (sinapoylglucose accumulator 2) mutant has identified another SCPL protein involved in plant secondary metabolism. The sng2 mutant was isolated by screening seed extracts for altered levels of sinapate esters, a group of phenylpropanoid compounds found in Arabidopsis and some other members of the Brassicaceae. Homozygous sng2 seeds accumulate sinapoylglucose instead of sinapoylcholine, and have increased levels of choline and decreased activity of the enzyme sinapoylglucose:choline sinapoyltransferase (SCT). Cloning of the SNG2 gene by a combination of map-based and candidate gene approaches demonstrates that SCT is another member of the growing class of SCPL acyltransferases involved in plant secondary metabolism.

Acyltransferases↗
PubMed2001

Mutations that reduce sinapoylmalate accumulation in Arabidopsis thaliana define loci with diverse roles in phenylpropanoid metabolism.

The products of phenylpropanoid metabolism in Arabidopsis include the three fluorescent sinapate esters sinapoylglucose, sinapoylmalate, and sinapoylcholine. The sinapoylmalate that accumulates in cotyledons and leaves causes these organs to appear blue-green under ultraviolet (UV) illumination. To find novel genes acting in phenylpropanoid metabolism, Arabidopsis seedlings were screened under UV for altered fluorescence phenotypes caused by changes in sinapoylmalate content. This screen identified recessive mutations at four Reduced Epidermal Fluorescence (REF) loci that reduced leaf sinapoylmalate content. Further analyses showed that the ref mutations affected other aspects of phenylpropanoid metabolism and some led to perturbations in normal plant development. A second class of mutations at the Bright Trichomes 1 (BRT1) locus leads to modest reductions in sinapate ester content; however, the most notable phenotype of brt1 mutants is the development of hyperfluorescent trichomes that appear to contain elevated levels of sinapate esters when compared to the wild type. These results indicate that at least five new loci affecting the developmentally regulated accumulation of phenylpropanoid secondary metabolites in Arabidopsis, and the cell specificity of their distribution, have been identified by screening for altered UV fluorescence phenotypes.

Alleles↗
PubMed2001

Localization of CYP86B1 in the outer envelope of chloroplasts.

CYP86B1 was cloned from a cDNA library and the protein expressed in E. coli. The protein gave the expected carbon monoxide difference spectrum. Using in vitro import assays with isolated pea chloroplasts, CYP86B1 was shown to be associated with the outer chloroplastic envelope membrane. This study provides the first direct evidence for a chloroplast-localized cytochrome P450-dependent monooxygenase.

Amino Acid Sequence↗
PubMed2000

Modified lignin in tobacco and poplar plants over-expressing the Arabidopsis gene encoding ferulate 5-hydroxylase.

Ferulate 5-hydroxylase (F5H) is a cytochrome P450-dependent monooxygenase that catalyses the hydroxylation of ferulic acid, coniferaldehyde and coniferyl alcohol in the pathways leading to sinapic acid and syringyl lignin biosynthesis. Earlier studies in Arabidopsis have demonstrated that F5H over-expression increases lignin syringyl monomer content and abolishes the tissue-specificity of its deposition. To determine whether this enzyme has a similar regulatory role in plants that undergo secondary growth, we over-expressed the F5H gene in tobacco and poplar. In tobacco, over-expression of F5H under the control of the cauliflower mosaic virus 35S promoter increased lignin syringyl monomer content in petioles, but had no detectable effect on lignification in stems. By contrast, when the cinnamate 4-hydroxylase (C4H) promoter was used to drive F5H expression, there was a significant increase in stem lignin syringyl monomer content. Yields of thioglycolic acid and Klason lignin in C4H-F5H lines were lower than in the wild-type, suggesting that F5H over-expression leads to a reduced deposition or an altered extractability of lignin in the transgenic plants. Histochemical analysis suggested that the novel lignin in C4H-F5H transgenic lines was altered in its content of hydroxycinnamyl aldehydes. Transgenic poplar trees carrying the C4H-F5H transgene also displayed enhanced lignin syringyl monomer content. Taken together, these data show that hydroxylation of guaiacyl-substituted lignin precursors controls lignin monomer composition in woody plants, and that F5H over-expression is a viable metabolic engineering strategy for modifying lignin biosynthesis in forest species.

Arabidopsis↗
PubMed2000

Cloning of the SNG1 gene of Arabidopsis reveals a role for a serine carboxypeptidase-like protein as an acyltransferase in secondary metabolism.

Serine carboxypeptidases contain a conserved catalytic triad of serine, histidine, and aspartic acid active-site residues. These enzymes cleave the peptide bond between the penultimate and C-terminal amino acid residues of their protein or peptide substrates. The Arabidopsis Genome Initiative has revealed that the Arabidopsis genome encodes numerous proteins with homology to serine carboxypeptidases. Although many of these proteins may be involved in protein turnover or processing, the role of virtually all of these serine carboxypeptidase-like (SCPL) proteins in plant metabolism is unknown. We previously identified an Arabidopsis mutant, sng1 (sinapoylglucose accumulator 1), that is defective in synthesis of sinapoylmalate, one of the major phenylpropanoid secondary metabolites accumulated by Arabidopsis and some other members of the Brassicaceae. We have cloned the gene that is defective in sng1 and have found that it encodes a SCPL protein. Expression of SNG1 in Escherichia coli demonstrates that it encodes sinapoylglucose:malate sinapoyltransferase, an enzyme that catalyzes a transesterification instead of functioning like a hydrolase, as do the other carboxypeptidases. This finding suggests that SCPL proteins have acquired novel functions in plant metabolism and provides an insight into the evolution of secondary metabolic pathways in plants.

Acyltransferases↗
PubMed1999

NMR characterization of lignins in Arabidopsis altered in the activity of ferulate 5-hydroxylase.

Nuclear magnetic resonance (NMR) of isolated lignins from an Arabidopsis mutant deficient in ferulate 5-hydroxylase (F5H) and transgenic plants derived from the mutant by overexpressing the F5H gene has provided detailed insight into the compositional and structural differences between these lignins. Wild-type Arabidopsis has a guaiacyl-rich, syringyl-guaiacyl lignin typical of other dicots, with prominent beta-aryl ether (beta-O-4), phenylcoumaran (beta-5), resinol (beta-beta), biphenyl/dibenzodioxocin (5-5), and cinnamyl alcohol end-group structures. The lignin isolated from the F5H-deficient fah1-2 mutant contained only traces of syringyl units and consequently enhanced phenylcoumaran and dibenzodioxocin levels. In fah1-2 transgenics in which the F5H gene was overexpressed under the control of the cauliflower mosaic virus 35S promoter, a guaiacyl-rich, syringyl/guaiacyl lignin similar to the wild type was produced. In contrast, the isolated lignin from the fah1-2 transgenics in which F5H expression was driven by the cinnamate 4-hydroxylase promoter was almost entirely syringyl in nature. This simple lignin contained predominantly beta-aryl ether units, mainly with erythro-stereochemistry, with some resinol structures. No phenylcoumaran or dibenzodioxocin structures (which require guaiacyl units) were detectable. The overexpression of syringyl units in this transgenic resulted in a lignin with a higher syringyl content than that in any other plant we have seen reported.

Arabidopsis↗
PubMed1999

New routes for lignin biosynthesis defined by biochemical characterization of recombinant ferulate 5-hydroxylase, a multifunctional cytochrome P450-dependent monooxygenase.

The enzymes and genes of the lignin biosynthetic pathway have been studied for several decades, but the gene encoding ferulate 5-hydroxylase (F5H) was cloned only 3 years ago by T-DNA tagging in Arabidopsis. To characterize the enzyme in detail, we have expressed F5H in yeast. According to current models of the phenylpropanoid pathway, F5H catalyzes the hydroxylation of ferulate to 5-hydroxyferulate; however, our studies indicate that the enzyme also uses coniferaldehyde and coniferyl alcohol as substrates. Unexpectedly, the K(m) values measured for the latter two substrates are three orders of magnitude lower than that measured for ferulic acid, suggesting that in lignifying tissues, syringyl monomers may be derived from their guaiacyl counterparts by hydroxylation and subsequent methylation. Thus, F5H may function later in the lignin biosynthetic pathway than was originally proposed. To further test this model, recombinant F5H was incubated together with ferulic acid, coniferaldehyde, or coniferyl alcohol in the presence of native or recombinant Arabidopsis caffeic acid/5-hydroxyferulic acid O-methyltransferase and [(14)C]S-adenosylmethionine. In all cases, the corresponding radiolabeled sinapyl derivatives were synthesized, indicating that the necessary enzymes required for this pathway are present in Arabidopsis. Taken together, these data suggest that the previously accepted pathway for lignin biosynthesis is likely to be incorrect.

Arabidopsis↗
PubMed1999

The responsiveness of the ICSmale questionnaire to outcome: evidence from the ICS-'BPH' study.

OBJECTIVE: To evaluate the responsiveness of the ICSmale questionnaire to the outcome of treatments for lower urinary tract symptoms (LUTS). PATIENTS AND METHODS: Consecutive men aged >45 years attending 23 urology centres in 12 countries, with symptoms suggestive of bladder outlet obstruction secondary to benign prostatic hyperplasia (BPH), were recruited to Phase I of the International Continence Society (ICS)-'BPH' study. In Phase II of the ICS-'BPH' study, 355 men in 15 centres in nine countries were followed up, having proceeded to treatment according to clinical practice. All men completed the ICS-'BPH' study questionnaire at baseline and follow-up, including the ICSmale which concerns LUTS and related problems. RESULTS: Patients included in Phase II were similar to those in Phase I according to age and levels of baseline symptoms. Patients received a range of treatments: 32% TURP, 29% drug therapies, 20% watchful waiting, 9% minimally invasive therapies and 10% 'others' (including open prostatectomy). For patients who underwent TURP, most LUTS, including voiding and filling symptoms, were highly statistically significantly better at follow-up than at baseline (P<0.0001). For drug, minimally invasive and 'other' treatments, fewer LUTS were highly statistically significantly better. For those undergoing watchful waiting, no symptoms were significantly different between baseline and follow-up. CONCLUSION: The ICSmale questionnaire, in addition to being psychometrically valid and reliable, is responsive to change in outcome.

Age Factors↗