Protein tyrosine phosphatases as negative regulators of the immune response.

In this mini-review, we provide an overview of those PTPs (protein tyrosine phosphatases) that are relevant to the immune response, highlighting the function of a number of intracellular and transmembrane PTPs that have been identified as having important negative regulatory roles on distinct aspects of host immunity.

The natural history of overactive bladder and stress urinary incontinence in older women in the community: a 3-year prospective cohort study.

AIMS: This is the first study designed to describe the natural history of stress urinary incontinence (SUI) and overactive bladder (OAB), using validated symptom syndrome severity scores developed for the purpose. METHODS: Two separate but related studies were involved, (i) a clinic sample (N = 2,052) from a randomised controlled trial (RCT) and (ii) a prospective cohort study (N = 12,750) with 3-year follow-up. Subjects in both studies were women aged 40 or more living in the community, approached using similar postal questionnaires. Severity scores using standardised urinary symptoms were derived for SUI and OAB from weightings obtained from logistic regression models of symptoms in relation to urodynamic diagnosis. Symptom severity scores were plotted for baseline and 3 years of follow-up to demonstrate the natural history of the main categories of SUI and OAB. RESULTS: Overactive bladder and SUI syndrome severity scores showed good criterion validity in relation to relevant clinical measures and good test-retest reliability. OAB severity increased progressively with age including a period of accelerated increase in the 60s. In contrast, SUI severity showed two age-related peaks around age 60 and again at age 80. SUI severity also showed a more fluctuating pattern from year to year compared to OAB. CONCLUSIONS: Contrasting patterns of natural history for OAB and SUI syndromes were identified consistent with differences in the patterns of related co-morbidities. Further studies are needed to confirm these findings.

Relationship between urinary symptoms reported in a postal questionnaire and urodynamic diagnosis.

AIMS: To describe the relationship between symptoms reported in a self-completed postal questionnaire and urinary disorders based on urodynamic investigation. METHODS: The study population was selected from women aged 40 years or over living in the community, who responded to a postal questionnaire. Following assessment and appropriate conservative interventions, those with a pre-defined level of severity of symptoms were offered urodynamic investigation. Logistic regression examined the association between urinary symptoms and the urodynamic diagnoses of detrusor overactivity (DO) and urodynamic stress incontinence (USI). RESULTS: Four hundred eighty-eight women completed urodynamic investigation; 29.1% (142/488) were found to have DO, 33.6% (164/488) USI, 20.7% (101/488) mixed incontinence, and 16.6% (81/488) no urodynamic abnormality. Stress incontinence (SI) and urge incontinence (UI) were included in the risk model for USI. SI reported monthly or more was associated with increased risk of USI, and UI reported weekly or more with decreased risk (sensitivity 76.9%; specificity 56.3%; positive predictive value (PPV) 67.8%). For DO, strong or overwhelming urgency, UI monthly or more, and nocturia once a night or more were all significantly associated with an increased risk while reporting of SUI monthly or more reduced the risk (sensitivity 63.1%; specificity 65.1%; PPV 63.1%). CONCLUSIONS: Urinary symptoms reported in a postal questionnaire are able to predict urodynamic diagnoses with moderate accuracy. These models may be useful tools with which to categorize urinary disorders for epidemiological study and, with further development, allocate first line treatment.

Validity and reliability of a questionnaire to measure the impact of lower urinary tract symptoms on quality of life: the Leicester Impact Scale.

AIMS: To develop a condition specific quality of life measure for males and females with urinary storage symptoms of urgency, frequency, nocturia and incontinence. MATERIALS AND METHODS: A sample of community dwelling males and females aged 40 years or more who were taking part in an epidemiological study provided data for development and validation of the scale. Questions were developed from literature review and discussions with clinicians and patients. Inclusion of items was dependent on levels of missing data and principal components analysis. Validity was assessed by comparison with the Hospital Anxiety and Depression Scale, the Bradburn Negative Affect Scale and single questions concerning the problematic nature of symptoms. Construct validity was assessed by comparing cases and non-cases, and patients with different symptom patterns. Test-retest and inter-rater reliability statistics were calculated for individual items. Responsiveness to change was measured in subjects taking part in a randomised controlled trial of a nursing intervention. RESULTS: The scale showed high levels of internal consistency and measures of construct validity were as hypothesised. Test-retest and inter-rater reliability was moderate to excellent. The distribution of scores was skewed with low levels of impact but the questionnaire was responsive to conservative treatments in patients receiving a nursing intervention. CONCLUSIONS: The questionnaire proved to be a valid and reliable interviewer administered instrument for measuring impact of urinary symptoms.

Storage symptoms of the bladder: prevalence, incidence and need for services in the UK.

OBJECTIVE: To establish valid and reliable prevalence and incidence rates for urinary incontinence and storage disorder, and estimate the extent of healthcare need and requirement for the UK. SUBJECTS AND METHODS: This was a cross-sectional and longitudinal population-based study involving registrants with 108 general practices in Leicestershire and Rutland counties (UK). In all, 162 533 (prevalence study) and 39 602 (incidence study) people aged > or = 40 years were approached by postal questionnaire, with response rates of 60% and 63%, respectively; 1050 non-responders were followed up. The main measures were incontinence (involuntary leakage) storage disorder (including incontinence or urgency or frequency or nocturia above clinically defined thresholds), storage symptoms (as for storage disorder, above epidemiologically defined thresholds), professionally defined healthcare need (storage disorder, or storage symptoms with an impact on quality of life, QoL), and healthcare requirement (using services or wanting help among those with a healthcare need), all within the last year. RESULTS: The period prevalence was: moderate or greater incontinence, 16.1%; storage disorder, 28.5%; storage symptoms with impact on QoL, 30.4%; healthcare need, 37.1% and requirement 20.4%. Among those with storage disorders 81% reported effects on QoL. Annual incidence rates were: incontinence, 6.3%; storage disorder, 14.1%; healthcare need, 15.6% and requirement 8.4%. The remission rates were substantially greater in men than women. The problem becomes increasingly established and less likely to remit with age. CONCLUSIONS: In the UK over a 1-year period, over a third of people aged > or = 40 years are estimated to have a healthcare need for urinary storage symptoms (i.e. 9 million) and a fifth (i.e. 5 million) are estimated to require healthcare, with unmet requirement affecting 3 million. This represents a major public health problem. Apparent inconsistencies between prevalence, impact and uptake of services are explained.

Continence nurse treatment of women's urinary symptoms.

The aim of this study was to establish how accurately a trained continence nurse could allocate appropriate second-line conservative treatment to women without urodynamic investigations. Depending on the number of patients coming taking up the service, there were between five and 12 nurses operating at any one time. Women aged 40 years and over, of which there were 2421 reporting lover urinary tract symptoms, were randomly allocated to a new nurse-led continence service. Of these women, 450 subsequently underwent urodynamic investigation, before which the nurses documented which second-line conservative treatment would be appropriate. The results showed that of all women with detrusor overactivity, 79.1% were correctly allocated anticholinergic treatment, and 64.8% were allocated pelvic floor exercises (PFE). Of all women with urodynamic stress incontinence, 88.8% were allocated only one treatment. This study showed that a trained continence nurse is able to allocate conservative treatment appropriately to the majority of women without the need for urodynamic investigation. This indicated that the management of urinary dysfunction by a team of trained, dedicated nurses has the potential to reduce waiting lists for urodynamic investigation, avoid unnecessary investigations and achieve greater patient satisfaction.

The association of diet and other lifestyle factors with overactive bladder and stress incontinence: a longitudinal study in women.

OBJECTIVES: To investigate the role of diet and other lifestyle factors in the incidence of overactive bladder and stress incontinence in women. Studies have suggested relationships between different aspects of lifestyle and symptoms of urinary incontinence, but there is a lack of firm evidence about their role in its cause. SUBJECTS AND METHODS: A random sample of women aged >or= 40 years living at home took part in a prospective cohort study. Baseline data on urinary symptoms, diet and lifestyle were collected from 7046 women using a postal survey and food-frequency questionnaire. Follow-up data on urinary symptoms were collected from 6424 of the women in a postal survey 1 year later. Logistic regression was used to investigate the association of food and drink consumption and other lifestyle factors with the incidence of overactive bladder and stress incontinence. RESULTS: In the multivariate model for the onset of an overactive bladder, there were significantly increased risks associated with obesity, smoking and consumption of carbonated drinks, and reduced risks with higher consumption of vegetables, bread and chicken. Obesity and carbonated drinks were also significant risk factors for the onset of stress incontinence, while consumption of bread was associated with a reduced risk. CONCLUSIONS: Causal associations with obesity, smoking and carbonated drinks are confirmed for bladder disorders associated with incontinence, and additional associations with diet are suggested. Behavioural modification of lifestyle may be important for preventing and treating these disorders.

An investigation into nonresponse bias in a postal survey on urinary symptoms.

OBJECTIVE: To investigate nonresponse bias in a postal survey on urinary symptoms in people aged >or= 40 years. SUBJECTS AND METHODS: Nonresponders to a postal survey on incontinence and other urinary symptoms were studied. A random sample of 1050 nonresponders (stratified for age and sex) was traced by a team of interviewers. Eligible nonresponders were asked several questions from the postal questionnaire, and their reason for not participating in the postal survey. RESULTS: Only 1% of those not responding were not traced in person or accounted for, and 12% were identified as not eligible to be in the survey sample (moved from address, deceased, residential home). Half of the eligible nonresponders (51%) did not answer the interviewer's questions, the main reason being general unwillingness or disinterest. The number in whom poor health was the reason increased with age. Comparing nonresponders who answered the interviewer's questions with a random sample of responders from the postal survey showed little difference in the reporting of urinary symptoms, although there were differences in general health and long-term health problems. Separate analyses by age showed greater reporting of some urinary symptoms and of poorer general health in the older nonresponders (>or= 70 years). CONCLUSION: Overall, for people aged >or= 40 years there was no evidence of a nonresponse bias in the reporting of urinary symptoms, providing confidence in such prevalence rates. However, poorer general health and greater reporting of some urinary symptoms by the older nonresponders (>or= 70 years) suggests prevalence rates in this age group may be underestimated.

Validity and reliability of an interviewer-administered questionnaire to measure the severity of lower urinary tract symptoms of storage abnormality: the Leicester Urinary Symptom Questionnaire.

OBJECTIVE: To develop a valid and reliable interviewer-administered questionnaire to measure the presence and severity of storage abnormality symptoms of incontinence, urgency, frequency and nocturia. SUBJECTS AND METHODS: Subjects were 930 men and women aged >/=40 years, taking part in a randomized controlled trial of a continence nurse practitioner (CNP) service. Criterion validity was tested by comparing questionnaire responses to 24-h pad test and 3-day urinary diary. Responsiveness was assessed by comparing questionnaire responses before and after treatment. Questions about urgency were investigated for construct validity in patients taking part in the trial who underwent urodynamic investigation (243). Test-retest and inter-rater reliability was measured at approximately 6 days in subjects recruited to an associated epidemiological study (104 and 102, respectively). RESULTS: The questionnaire responses showed significant associations with pad-test and diary measures. Questions about the severity of daytime incontinence performed better than those measuring night-time incontinence. The response categories of soaked, wet, damp and almost dry had better associations with the pad test than other measures of the severity of incontinence. Test-retest and inter-rater reliability was good for all questions, and all were responsive to change in symptoms, showing significant differences before and after treatment. CONCLUSION: There is a clear need for standardization of measurement using well-validated instruments. This interviewer-administered questionnaire is valid, reliable and sensitive to change in a wide range of severity of symptoms, and in both men and women aged >/=40 years. The questionnaire provides a useful assessment tool for primary and secondary care in research and clinical settings.

Prevalence of faecal incontinence in adults aged 40 years or more living in the community.

BACKGROUND: Prevalence studies of faecal incontinence in the general population are rare and the impact of faecal incontinence on quality of life has not been previously addressed. AIMS: To establish the prevalence of faecal incontinence in adults in terms of frequency of leakage, degree of soiling, and level of impact on quality of life. METHODS: In a cross sectional postal survey, 15 904 adults aged 40 years or more (excluding residents of nursing and residential homes) were selected randomly by household from the Leicestershire Health Authority patient register. Participants were asked to complete a confidential health questionnaire. Major faecal incontinence was defined as soiling of underwear or worse with a frequency of several times a month or more. Respondents were also asked if bowel symptoms had an impact on their quality of life. RESULTS: From a total sample of 10 116 respondents, 1.4% reported major faecal incontinence and 0.7% major faecal incontinence with bowel symptoms that had an impact on quality of life. Major faecal incontinence was significantly associated with a lot of impact on quality of life (odds ratio 12.4, 95% confidence interval 7.5-20.6). Incontinence was more prevalent and more severe in older people but there was no significant difference between men and women. CONCLUSIONS: This study has confirmed that faecal incontinence is a fairly common symptom, particularly in older people. Faecal incontinence in men has received little attention in the past and the results from this study indicate that it is as much of a problem in men as it is in women while the level of unmet need in this group is high. Estimates of need for health care for this symptom should be multidimensional and assess both the severity of symptoms and the impact it has on quality of life.

Requirement for CD28 co-stimulation is lower in SHP-1-deficient T cells.

This study provides biochemical and functional evidence pertaining to the role of the intracellular protein tyrosine phosphatase, SHP-1, in influencing thresholds for TCR activation. Although the loss of SHP-1 in thymocytes from motheaten mice had minimal effects on the initial rise of cytosolic Ca(2+) concentration following TCR triggering, the post-stimulation equilibrium levels of Ca(2+) were consistently elevated. In keeping with a SHP-1 effect on PLCgamma function, IP3 generation was increased in SHP-1 deficient thymocytes. Importantly, we demonstrate that loss of SHP-1 results in a relaxation of the normally stringent co-stimulatory requirements for IL-2 production. SHP-1 deficient single-positive CD4(+) thymocytes revealed a significantly enhanced capacity to produce IL-2 in response to anti-CD3 stimulation alone. In contrast, the simultaneous triggering of CD3 and CD28 was required for equivalent IL-2 production in control single-positive CD4(+) thymocytes. Furthermore, SHP-1 deficient thymocytes generated an increased and prolonged proliferative response to anti-CD3 stimulation alone. In addition, the simultaneous triggering of CD28 and CD3 resulted in equivalent proliferative responses in SHP-1-deficient and control thymocytes, suggesting that a strong co-stimulatory signal is able to override the effect of SHP-1 loss on TCR hyperresponsiveness. Collectively, these results suggest that SHP-1, rather than acting directly on TCR signaling, may indirectly raise thresholds for TCR triggering by modulating co-stimulatory signals.

Community surveys of late-life depression: who are the non-responders?

BACKGROUND: community surveys of depression among older people may be particularly prone to non-response. Information on non-responders is difficult to obtain and often limited to demographics. Therefore, the full extent of response bias is not always known. OBJECTIVE: to determine factors associated with non-response at each stage of a two-stage survey of late-life depression. SETTING: one large general practice (registered population >30000) serving the market town of Melton Mowbray, Leicestershire, UK. SUBJECTS: community residents (n=2633) aged 65-74 years registered with the practice. METHODS: a two-stage community survey of patients aged 65-74 years. The first stage was an interviewer-administered general health survey including a measure of depressive symptoms. We asked those who screened positive for possible depression to undergo a semi-structured psychiatric interview. We compared use of services and medication by non-responders and responders to both stages using primary-care records. We compared Townsend deprivation scores using data obtained from the 1991 census. RESULTS: responders to stage 1 were more likely to use both primary [odds ratio (OR) 1.65, 95% confidence interval (CI) 1.38-1.96] and secondary (OR 1.59, 95% CI 1.25-2.02) services and tended to live in more affluent areas (P=0.002). At stage 2, the only difference observed was a lower level of use of tranquillisers or hypnotics among responders (OR 0.27, 95% CI 0.11-0.67). CONCLUSIONS: older people with low levels of contact with health services may be under-represented in community surveys of depression. Investigators should look outside traditional health settings to promote the uptake of response in these studies.

Constitutive association of SHP-1 with leukocyte-associated Ig-like receptor-1 in human T cells.

The intracellular Src homology 2 (SH2) domain-containing protein tyrosine phosphatase (SHP-1) is a negative regulator of cell signaling and contributes to the establishment of TCR signaling thresholds in both developing and mature T lymphocytes. Although there is much functional data implicating SHP-1 as a regulator of TCR signaling, the molecular basis for SHP-1 activation in T lymphocytes is poorly defined. A modification of the yeast two-hybrid system was employed to identify in T cells phosphotyrosine-containing proteins capable of binding the SH2 domains of SHP-1. From this yeast tri-hybrid screen, the p85beta subunit of phosphatidylinositol 3-kinase and the immunoreceptor tyrosine-based inhibitory motif-containing receptors, leukocyte-associated Ig-like receptor-1 (LAIR-1) and programmed death-1 (PD-1), were identified. Coimmunoprecipitation studies demonstrated that the exclusive phosphotyrosine-containing protein associated with SHP-1 in Jurkat T cells under physiological conditions is LAIR-1. Significantly, this interaction is constitutive and was detected only in the membrane-enriched fraction of cell lysates. Ligand engagement of the SH2 domains of SHP-1 is a prerequisite to activation of the enzyme, and, consistent with an association with LAIR-1, SHP-1 was found to be constitutively active in unstimulated Jurkat T cells. Importantly, a constitutive interaction between LAIR-1 and SHP-1 was also detected in human primary T cells. These results illustrate the sustained recruitment and activation of SHP-1 at the plasma membrane of resting human T cells by an inhibitory receptor. We propose that this mechanism may exert a constitutive negative regulatory role upon T cell signaling.

TCR signaling thresholds regulating T cell development and activation are dependent upon SHP-1.

An examination of thymocytes and peripheral T cells from SHP-1-deficient motheaten mice possessing a transgenic MHC class I-restricted TCR has implicated SHP-1 in regulating TCR signaling thresholds at three checkpoints in T cell development and activation. First, in the population of CD4-CD8- double negative thymocytes, SHP-1 appears capable of regulating signals from TCR complexes that control the maturation and proliferation of double negative thymocytes. Second, the loss of SHP-1 increased the number of CD4+CD8+ double positive thymocytes capable of maturing as TCRhigh single positive thymocytes. Third, the loss of SHP-1 altered the basal level of activation of naive lymph node T cells. Accordingly, SHP-1-deficient lymph node T cells bearing the transgenic TCR demonstrated a hyperresponsiveness to stimulation with cognate peptide. However, the loss of SHP-1 did not alter the cytolytic ability of mature effector cytotoxic T lymphocytes. Together these results suggest that SHP-1 contributes to establishing thresholds for TCR signaling in thymocytes and naive peripheral T cells.

Comparison of CD45 extracellular domain sequences from divergent vertebrate species suggests the conservation of three fibronectin type III domains.

Mammalian CD45 is a transmembrane protein tyrosine phosphatase expressed by all nucleated cells of hematopoietic origin. In lymphocytes, CD45 is required for Ag-induced signal transduction due to its ability to positively regulate Src family members. The mechanisms by which CD45 function is regulated are unknown. Indeed, the interactions of CD45 extracellular domains are largely undefined. To gain insight into potentially important regions of the extracellular domain, we sought to identify conserved features from divergent species. cDNAs encoding the putative CD45 homologue from Heterodontus francisci (horned shark) were isolated. The cDNA sequence predicts a protein of 1200 amino acids that contains a 452-amino acid extracellular domain, a 22-amino acid transmembrane region, and a 703-amino acid cytoplasmic domain. Alignment searches revealed that the Heterodontus cytoplasmic domain sequence was most identical to mammalian CD45 and a transmembrane protein tyrosine phosphatase sequence identified from chickens, ChPTP lambda. A dendrogram with other transmembrane protein tyrosine phosphatase sequences suggest that the Heterodontus and chicken sequences represents CD45 orthologues for their respective species. Analysis of vertebrate CD45 extracellular domain sequences indicates the conservation of three structural regions: a region containing potential O-linked carbohydrate sites, a cysteine-containing region, and a region containing three fibronectin type III domains. For each vertebrate species, multiple isoforms are generated by alternative splicing of three exons that encode a portion of the region containing potential O-linked glycosylation sites. These studies provide evidence for a conservation in CD45 extracellular domain structure between divergent species and provide a basis for understanding CD45 extracellular domain interactions.

Direct regulation of ZAP-70 by SHP-1 in T cell antigen receptor signaling.

The threshold at which antigen triggers lymphocyte activation is set by the enzymes that regulate tyrosine phosphorylation. Upon T cell activation, the protein tyrosine phosphatase SHP-1 was found to bind to the protein tyrosine kinase ZAP-70. This interaction resulted in an increase in SHP-1 phosphatase activity and a decrease in ZAP-70 kinase activity. Expression of a dominant negative mutant of SHP-1 in T cells increased the sensitivity of the antigen receptor. Thus, SHP-1 functions as a negative regulator of the T cell antigen receptor and in setting the threshold of activation.

A role in B cell activation for CD22 and the protein tyrosine phosphatase SHP.

CD22 is a membrane immunoglobulin (mIg)-associated protein of B cells. CD22 is tyrosine-phosphorylated when mIg is ligated. Tyrosine-phosphorylated CD22 binds and activates SHP, a protein tyrosine phosphatase known to negatively regulate signaling through mIg. Ligation of CD22 to prevent its coaggregation with mIg lowers the threshold at which mIg activates the B cell by a factor of 100. In secondary lymphoid organs, CD22 may be sequestered away from mIg through interactions with counterreceptors on T cells. Thus, CD22 is a molecular switch for SHP that may bias mIg signaling to anatomic sites rich in T cells.

Mutations at the murine motheaten locus are within the hematopoietic cell protein-tyrosine phosphatase (Hcph) gene.

Mice homozygous for the recessive allelic mutation motheaten (me) or viable motheaten (mev) on chromosome 6 develop severe defects in hematopoiesis. In this paper we present the findings that the me and mev mutations are within the hematopoietic cell protein-tyrosine phosphatase (Hcph) gene. High resolution mapping localized me to an area tightly linked to Hcph on chromosome 6. Abnormalities of the Hcph protein product were demonstrated by Western blot analysis and by activity assays in both me/me and mev/mev mice. Molecular analysis of the Hcph cDNA identified abnormal transcripts in both mutants. DNA sequence analyses of cDNA and genomic clones revealed that both the me and mev mutations are point mutations that result in aberrant splicing of the Hcph transcript. These findings provide the first available animal models for a specific protein-tyrosine phosphatase deficiency, thus facilitating determination of the precise role of this signaling molecule in hematopoiesis.

Do changes in transcardiac impedance modulation correlate with haemodynamic status?

Implantable cardiac pacemakers and defibrillators have the ability to revert a variety of arrhythmias to normal sinus rhythm. For correct operation, such devices require accurate arrhythmia classification. Arrhythmia classification by these devices could be improved with the addition of a suitable haemodynamic sensor. This study investigated the use of transcardiac impedance for haemodynamic sensing. Ventricular fibrillation, ventricular tachycardia, electro-mechanical dissociation and five rates of ventricular pacing, each having a different associated level of haemodynamic compromise, were induced in each of seven mongrel dogs. The amplitude responses of the modulations of transcardiac impedance were compared with those of arterial pulse pressure (an established measure of haemodynamic status), and changes in cycle length. The correlation coefficient for changes in transcardiac impedance modulation amplitude and arterial pulse pressure was found to be 0.89. For transcardiac impedance modulation amplitude and cycle length, the correlation coefficient was 0.77, and for arterial pulse pressure and cycle length, the correlation coefficient was 0.85. In the acute anaesthetised dog, changes in the amplitude of transcardiac impedance modulations were shown to reflect different levels of haemodynamic status.