PubMed Health⌕ Search

Biomedical subjects

L L Ng

Publications and source records attributed to L L Ng.

At least 19 recordsLinked to original sources
PubMed2005

Complementary roles of simple variables, NYHA and N-BNP, in indicating aerobic capacity and severity of heart failure.

AIMS: The extent of exercise intolerance in patients with chronic heart failure (CHF) is dependent on and representative of the severity of heart failure. However, few primary care physicians have direct access to facilities for formal exercise testing. We have therefore explored whether information readily obtainable in the community can reliably predict the functional capacity of patients. METHODS AND RESULTS: Ninety-six subjects with a wide range of cardiac function (10 healthy controls and 86 CHF patients with NYHA classes I-IV, LVEF 36.9+/-15.2%) were recruited into the study and had resting plasma N-BNP and cardiopulmonary exercise testing to measure peak oxygen consumption (VO2). Significantly higher N-BNP levels were found in the CHF group (299.3 [704.8] fmol/ml, median [IQR]) compared with the healthy control group (7.2 [51.2] fmol/ml), p<0.0001. There were significant correlations between peak VO2 and N-BNP levels (R=0.64, P<0.001), peak VO2 and NYHA class (R=0.76, P=0.001), but no significant correlation was seen between peak VO2 and LVEF (R=0.0788, P=0.33). Multivariate analysis identified plasma N-BNP (P<0.0001) and NYHA class (P<0.0001) as significant independent predictors of peak VO2. Logistic modelling with NYHA class and log N-BNP to predict peak VO2<20 ml/kg/min showed that the area under the curve of receiver-operating-characteristic (ROC) curve was 0.906 (95% CI 0.844-0.968). A nomogram based on the data has been constructed to allow clinicians to estimate the likelihood of peak VO2 to be <20 ml/kg/min for given values of plasma N-BNP and NYHA class. CONCLUSIONS: By combining information from a simple objective blood test (N-BNP) and a simple scoring of functional status (NYHA), a clinician can deduce the aerobic exercise capacity and indirectly the extent of cardiac dysfunction of patients with CHF.

Adult↗
PubMed2004

Diagnosis of heart failure using urinary natriuretic peptides.

In the present study, we assessed the use of urinary natriuretic peptides [N-terminal proatrial natriuretic peptide (N-ANP) and N-terminal pro-brain natriuretic peptide (N-BNP) and C-type natriuretic peptide (CNP)] in the diagnosis of heart failure. Thirty-four consecutive hospitalized heart failure patients (median age, 75.5 years; 14 female) were compared with 82 age- and gender-matched echocardiographically normal controls. All subjects provided plasma and urine specimens. Plasma was assayed for N-BNP, and urine was assayed for N-ANP, N-BNP and CNP. The diagnostic efficiency of peptides was assessed using receiver operating characteristic (ROC) curve analysis. All three urinary natriuretic peptides were significantly elevated in heart failure patients ( P <0.001). Urine N-BNP was correlated with plasma N-BNP ( r (s)=0.53, P <0.0005). Areas under the ROC curves for urinary N-ANP, N-BNP and CNP were 0.86, 0.93 and 0.70 and for plasma N-BNP was 0.96. Correcting urinary peptide levels using urine creatinine produced ROC areas of 0.89, 0.93 and 0.76 respectively. A urine N-BNP level cut-off point of 11.6 fmol/ml had a sensitivity and specificity for heart failure detection of 97% and 78% respectively, with positive and negative predictive values of 64.7 and 98%. In conclusion, although all three natriuretic peptides were elevated in urine in heart failure, urinary N-BNP had diagnostic accuracy comparable with plasma N-BNP. Use of urinary N-BNP for heart failure diagnosis may be suitable for high-throughput screening, especially in subjects reluctant to provide blood samples.

Aged↗
PubMed2003

Plasma N-terminal pro-brain natriuretic peptide in Type 1 diabetic patients with and without diabetic nephropathy.

AIMS: Plasma N-terminal pro-brain natriuretic peptide (NT proBNP) is produced and released from cardiac ventricles; it is elevated in patients with heart failure, hypertension and chronic renal failure. This study aimed to examine the plasma levels of NT proBNP and their relationship in Type 1 diabetic patients with and without diabetic nephropathy. METHODS: We developed a non-competitive immunoluminometric assay with in-house antibodies to the N- and C-terminal domains of NT proBNP. We compared NT proBNP levels between 47 normoalbuminuric patients (group 1), 12 microalbuminuric patients (group 2) and 12 patients with macroalbuminuria (group 3). RESULTS: There were significant differences in 24-h systolic and diastolic blood pressure, diabetes duration, serum creatinine, LDL-cholesterol and HbA1c between the three groups; other parameters did not differ significantly. NT proBNP (median and range) levels were 5 (0.75-68), 22 (0.75-82) and 23 (0.75-374) fmol/ml for groups 1-3, respectively. Log-transformed data of NT proBNP were used to compare all three groups (P=0.016). The Pearson correlation between NT proBNP and albuminuria (R=0.27; P=0.02) was positive; HbA1c (R=0.25; P=0.03) and age (R=0.33; P=0.005) correlated significantly as well. On the basis of multiple regression analysis, the adjusted difference remained significant between the three groups. CONCLUSIONS: This is the first demonstration that NT proBNP levels are significantly higher in Type 1 diabetic patients with albuminuria. This may be caused by a down-regulation of A-type guanylate cyclase-coupled natriuretic peptide receptors in renal tubules or by elevated NT proBNP levels leading to higher glomerular hydraulic pressure or higher capillary permeability and possibly increased albumin excretion. Further studies are required to investigate the potential role of NT proBNP in patients with diabetic nephropathy and such other co-morbidities as cardiovascular disease.

Adult↗
PubMed2003

The development of geriatric psychiatry services in Singapore.

Singapore is ageing rapidly and the need to develop a comprehensive range of psychiatric services for the elderly is urgent. To cater to the increase in the number of elderly with mental health problems, a multi-pronged, collaborative approach to developing services is necessary. Over the last decade, the development of such services has been initiated by the Department of Geriatric Psychiatry, Woodbridge Hospital and Institute of Mental Health, and effected through dynamic elderly networks consisting of health, social and voluntary organisations. This has facilitated the integration of psychogeriatric services within the overall framework of elderly services. With the establishment of the Integrated Framework of Healthcare of the Elderly by the Ministry of Health in 2000, the importance and effectiveness of building partnerships in service provision have been demonstrated. The challenge for the future is to attract and retain geriatric-trained healthcare professionals, enhance their training in the early diagnosis and management of psychiatric disorders in the elderly, improve the support of family caregivers and expand the range of quality psychogeriatric services.

Aged↗
PubMed2003

Prescribing psychoactive medications in nursing homes: current practice in Singapore.

AIM: To assess the prescribing practice, use and potential adverse effects of psychoactive medications in Singapore nursing homes. METHOD: From a list of existing 24 voluntary welfare organisation (VWO) run nursing homes, four homes with the largest bed capacity were selected from the eastern zone of Singapore. When contacted, two homes agreed to participate in the study. Medical records of all residents aged 65 years and above were reviewed to obtain demographic information, clinical diagnoses and medication orders. Two geriatricians and one psychogeriatrician reviewed the psychoactive medications used in these nursing homes. RESULT: A Total of 384 residents were enrolled in the study. Mean age of the participants was 79.1 years (65-107); 60.7% were female and 92.4% were Chinese. Dementia was documented for 131 (34.1%) residents, depression for 50 (13%) residents. Residents were on an average of 5.2 (0-14) medications. A total of 309 psychoactive medications were prescribed for the residents. Fifty-nine (63%) antipsychotics, 42 (65%) Benzodiazepines, 65 (61%) antidepressants, 10 (77%) others sedatives and 31 (100%) anticonvulsants were deemed inappropriate. Lack of documented indication, potential adverse drug reaction, drug-drug interaction and therapeutic duplication were the most common medication related problems observed in this study. CONCLUSION: Majority of the nursing home residents were on psychoactive medications. Residents with dementia were more likely to be on psychoactive medications. Statistically significant association was observed between the use of inappropriate psychoactive medications and the diagnosis of dementia. Better documentation of clinical diagnoses and indications, and regular medication review for potential adverse drug reactions would improve the quality of care in Singapore nursing homes.

Aged↗
PubMed2002

Altered Na+/H+ exchanger isoform 1 activity in immortalized lymphoblasts from women with pre-eclampsia: evidence for an intermediate phenotype.

Previous studies have demonstrated a raised Na(+) content in leucocytes isolated from women with pre-eclampsia. Increased Na(+)/H(+) exchanger activity is one membrane transport abnormality that may contribute to this phenomenon and may be implicated in the abnormal volume homoeostasis and hypertension associated with the disease. Increased Na(+)/H(+) exchanger activity has been documented in nucleated white blood cells from both pre-eclamptic and post-partum pre-eclamptic women, and may suggest the importance of genetic influences on exchanger activity. In the present study, we used lymphoblasts from women with pre-eclampsia and from age- and gestation-matched normotensive pregnant controls to determine Na(+)/H(+) exchanger activity and intracellular resting pH using fluorimetry and the pH-sensitive dye BCECF-AM [bis(carboxyethyl)carboxyfluorescein acetoxymethyl ester]. Determination of Na(+)/H(+) exchanger protein abundance was performed by Western blotting. Intracellular pH was not significantly different in cells from pre-eclamptic women compared with those from normotensive controls. Na(+)/H(+) exchanger activity was measured when the intracellular pH was clamped at 6.0, and was found to be significantly higher in cells from pre-eclamptic women (20.77+/-0.92 mmol x min(-1) x l(-1)) compared with those from normotensive controls (15.22+/-0.92 mmol x min(-1) x l(-1); P =0.001). Na(+)/H(+) exchanger protein abundance was established to be similar in the two subject groups, suggesting that the turnover number for the Na(+)/H(+) exchanger is increased in the women with pre-eclampsia. These changes in Na(+)/H(+) exchanger activity indicate the importance of genetic factors in determining this particular phenotype, since in this cell culture model of pre-eclampsia it is likely that environmental or hormonal influences present in vivo would have declined. Overactivity of the Na(+)/H(+) exchanger may contribute to the raised intracellular Na(+) concentration reported previously in white blood cells from women with pre-eclampsia.

Adult↗
PubMed2001

Depression in Singapore: failure to demonstrate an age effect on clinical features.

OBJECTIVES: Studies comparing older and younger depressed patients have variably identified differing and similar clinical feature patterns, an inconsistency requiring clarification and explanation. If influential, age may have a true phenotypic effect or be a secondary influence reflecting depressive sub-type differences. If age is primarily influential, then, after controlling for depressive sub-type differences its effect should impact on clinical features - even in non-western regions. METHODS: We therefore undertook a study in Singapore, comparing 42 elderly and 28 younger patients of a Singapore psychiatric hospital, and with the diagnostic sub-type profile similar across the age-based groups. RESULTS: Despite the elderly group being some 35 years older, both at first episode and when surveyed, and having a distinctly higher rate of physical disorders, few clinical differences were identified. While the elderly group reported a less severe depressed mood and more 'somatic' symptoms, analyses indicated that such differences were accounted for by education and language factors, and were compatible with the view that Chinese subjects historically report depression more 'somatically'. CONCLUSION: We conclude that, in a non-western, largely Chinese sample of depressed patients, few differences in the phenotypic expression of depression were identified, perhaps reflecting similar distributions of depressive sub-types across the groups, an issue which may have muddied interpretation of western studies.

Adolescent↗
PubMed2001

Plasma N-terminal pro BNP and cardiotrophin-1 are elevated in aortic stenosis.

BACKGROUND: Echocardiography with Doppler examination of the aortic valve provides a very accurate assessment of the transvalvular gradient and is used to monitor progression of aortic stenosis (AS). Plasma brain natriuretic peptide (BNP) has been shown to correlate with end-systolic wall stress in patients with AS. AIM: We hypothesized that plasma N-terminal proBNP (NT proBNP) and a newly identified cytokine cardiotrophin-1 (CT-1), which has been shown to stimulate BNP production at a transcriptional level are elevated in patients with AS and correlate to the maximum trans-valvular aortic pressure gradient (TVPG). METHOD: We compared plasma NT proBNP and CT-1 in 15 AS patients [five males, mean age 79 years [range 60-94], mean TPVG 39.3 mmHg (20-100)] with 10 controls (five male, mean age 68 years [56-79]). Results are expressed as mean [ranges] and comparisons were by the Mann-Whitney test. RESULTS: NT proBNP levels were elevated in AS patients [252.9 fmol/ml (79.2-541.8)] when compared with the controls (157.2 fmol/ml [104.7-236.9], P<0.005). Also CT-1 levels were elevated in AS patients (57.3 fmol/ml [33-86.3] when compared with the controls [28.3 fmol/ml (6.9-48.3), P<0.0005]. Both NT proBNP and CT-1 levels were correlated to the TVPG (r=0.53 and r=0.65, P<0.05 and P=0.009, respectively). On best subset analysis the strongest correlate with TVPG was CT-1 (R2=38%). The addition of NT proBNP did not improve diagnostic accuracy (R2=39%). CONCLUSION: These results suggest NT proBNP and CT-1 levels increase in proportion to the TVPG and could potentially be used to monitor progression of disease non-invasively. These markers may also be useful to identify the optimum time for surgery in AS.

Aged↗
PubMed2001

Prolonged stability of endogenous cardiotrophin-1 in whole blood.

Cardiotrophin-1 (CT-1) is a recently identified cytokine of the interleukin-6 (IL-6) family that signals through the gp130 signalling pathway. CT-1 may be of central importance to the pathogenesis of ventricular remodelling in patients with acute myocardial infarction (AMI) and therefore have clinical value in the identification of patients with impaired ventricular function. Central to the clinical use of CT-1 is in the in vitro stability of the peptide. Twelve subjects were recruited. A total of 25 mL of peripheral venous blood was collected into chilled polypropylene tubes containing EDTA and aprotinin and divided into 5 aliquots. One sample was spun in a prerefrigerated centrifuge (4 degrees C) at 3,000 rpm for 10 minutes and plasma separated and frozen at -70 degrees C immediately. Remaining samples were stored for 24 and 48 hours at room temperature or on ice. CT-1 in extracted plasma specimens was measured with a competitive chemiluminescent assay. The concentration of CT-1 in samples stored optimally was 43.1 +/- 6.05 fmol/mL. CT-1 levels for storage at room temperature compared with ice at the remaining time points were as follows: 24 hours, 41.5 +/- 5.76 v 37.5 +/- 8.66; and 48 hours, 42.6 +/- 6.28 v 41.0 +/- 5.42 fmol/mL. There were no significant changes in concentrations of CT-1 stored optimally or kept for up to 48 hours in aliquots of whole blood at room temperature or on ice. We conclude that CT-1 is stable in specimens of whole blood treated with EDTA and aprotinin and stored for up to 48 hours at room temperature or on ice, hence permitting its development in the routine clinical investigation of patients with heart failure.

Adult↗
PubMed2001

Potassium and activity of the sodium hydrogen exchanger isoform 1 in vascular smooth muscle of hypertensive rats.

Low potassium intake is inversely associated with blood pressure. In vitro, the proliferation of vascular smooth muscle cells (VSMCs) shows an inverse correlation with [K(+)]. In hypertension, many studies have established that the ubiquitous Na(+)/H(+) exchanger isoform 1 (NHE-1) exhibits increased activity and is permissive for cell proliferation. Changes in extracellular [K(+)] lead to altered intracellular Na(+) content, which could affect NHE activity and NHE-1 protein expression. We therefore investigated the effects of altering extracellular [K(+)] on NHE activity and NHE-1 expression in cultured VSMCs of both the spontaneously hypertensive rat (SHR) and its normotensive Wistar-Kyoto counterpart (WKY). Culture of SHR VSMCs for 48 hours in media containing 2, 4, 6, and 8 mmol. L(-1) [K(+)] led to activation of NHE-1 in the low [K(+)] media (NHE-1 activity at [K(+)] 2, 4, 6, and 8 mmol. L(-1) were 34.3 +/- 1.7, 29.5 +/- 1.1, 27.7 +/- 1.4, and 26.1 +/- 2.1 mmol. L(-1) min(-1), P <.006 by analysis of variance [ANOVA]). This was not associated with any significant changes in intracellular pH. By contrast, WKY VSMCs did not exhibit any significant activation of NHE-1 in low [K(+)] media (NHE-1 activity at [K(+)] 2, 4, 6, and 8 mmol. L(-1) were 24.3 +/- 2.9, 22.3 +/- 1.7, 19.0 +/- 1.8, and 18.6 +/- 1.6 mmol. l(-1) min(-1), P = not significant [NS] by ANOVA). Culture of SHR or WKY VSMCs in low [K(+)] media did not alter NHE-1 protein expression, suggesting the enhancement of activity in SHR cells was due to an increased turnover number of NHE-1. This response of NHE-1 in SHR VSMCs to K(+) depletion indicated a direct effect on these cells and could potentially enhance the contractile or proliferative phenotype of these cells in vivo.

Animals↗
PubMed2001

Leucocyte intracellular pH and Na+/H+ exchanger isoform-1 activity in postpartum women with pre-eclampsia.

OBJECTIVE: To investigate leucocyte Na+/H+ exchanger isoform 1 activity in postpartum pre-eclamptics. DESIGN: Exchanger isoform-1 activity and intracellular resting pH were established in leucocytes isolated from two study groups. SAMPLE: Leucocytes isolated from 10 women who had had pre-eclamptic pregnancies more than five months postpartum, and from 10 age-matched normotensive women who were more than five months postpartum. SETTING: Hypertension Clinic, Antenatal Assessment Area, Leicester Royal Infirmary. METHODS: A well validated technique involving flurometry using a pH sensitive dye (BCECF-AM) was performed to determine exchanger isoform-1 activity and intracellular pH. Determination of exchanger isoform-1 protein abundance was performed by western blotting. Exchanger isoform-3 protein abundance was examined to rule out the possibility of activity due to this particular isoform. RESULTS: Intracellular pH was significantly lower in the postpartum pre-eclamptic group (7.11 +/- 0.02), compared with the postpartum normotensive controls (7.33 +/- 0.04; P < 0.001). Exchanger isoform-1 efflux rate (in mmol/L/minute) was significantly higher in the postpartum pre-eclamptic group (35.91 +/- 3.1), compared with the postpartum normotensives (23.94 +/- 2.0; P = 0.005). Exchanger isoform-1 protein density was established to be similar among the two subject groups. No exchanger isoform-3 protein was identified by western blotting. CONCLUSION: Our results suggest that elevated exchanger isoform-1 activity is an important finding in women who have suffered from pre-eclampsia. This increased activity is not due to an increase in exchanger isoform-1 protein abundance or the presence of exchanger isoform-3.

Adult↗
PubMed2001

Falls amongst institutionalised psycho-geriatric patients.

Falls are common among the elderly patients in the psycho-geriatric wards and yet they have been understudied. A fall is a multi-factorial syndrome involving the patient and the environment. Psycho-geriatric patients who fall may suffer serious physical injuries that result in morbidity, further institutionalisation or even mortality. This study aims to examine the contributing factors to, and morbidity and outcome of falls among institutionalised psycho-geriatric patients so that preventive strategies can be refined. Data of patients who fell over a year's period in four psycho-geriatric wards were collected retrospectively and compared with those who had not fallen within the same period. The general profile of the psycho-geriatric patient who falls is one who is: above seventy-five years old; on three or more medications; and having recent changes in medication and mental status. About one in three fallers fell repeatedly. The rate of serious injury and mortality was low. In conclusion, while many factors are attributable to the common effects of aging and physical illnesses; psychotropic medication, change in mental state and specific environmental factors also play significant contributory roles to falls in this group of patients.

Accidental Falls↗
PubMed2000

Validation and comparison of three brief depression scales in an elderly Chinese population.

The study aimed to establish the diagnostic accuracy of the Geriatric Depression Scale (GDS), the Even Briefer Assessment Scale for Depression (EBAS DEP), and the single question test for depression in our elderly Chinese population, and to determine if any one instrument was to be preferred. Ninety-eight community-living, socially active and non-depressed elderly and 75 patients diagnosed with depression were administered the three depression scales. Receiver operating characteristics (ROC) were employed to determine the optimal cut-off scores for the GDS and EBAS DEP, and the diagnostic performance of all three instruments were then compared. ROC analysis indicated an optimal cut-off score of 4 and above for the 15-item GDS, with a sensitivity of 84.0% and a specificity of 85.7%, while the EBAS DEP had 77.3% sensitivity and 89.8% specificity at the optimal cut-off score of 3 and above. The sensitivity and specificity of the single question were 64.0% and 94.9%, respectively. The non-parametric test of the areas-under-the-curve showed no significant difference between the diagnostic performances of the GDS and the EBAS DEP; visually, however, the ROC plot of the GDS was superior. The GDS, the EBAS DEP, and the single question were all valid screening tools for depression in the elderly Chinese population. For busy physicians, there is rationale to first use the single-question test, supplemented where necessary with either the GDS or the EBAS DEP, as an efficient diagnostic strategy for identifying depression amongst older Chinese patients.

Aged↗
PubMed2000

Cardiotrophin-1 protects the human myocardium from ischemic injury. Comparison with the first and second window of protection by ischemic preconditioning.

BACKGROUND: There are reports suggesting that cardiotrophin 1 (CT-1) is cytoprotective. We investigated the cardioprotective effects of CT-1 on the human myocardium and compared this benefit with the early and delayed protection afforded by ischemic preconditioning (PC). METHODS: Right atrium specimens were prepared and incubated in buffer solution at 37 degrees C for 30 min stabilisation, before entering one of the three following studies. In study 1, muscles (n=6/group) were allocated to one of four groups: (i) aerobic control - incubated in oxygenated media for 210 min, (ii) ischemia alone - 90 min ischemia followed by 120 min reoxygenation, (iii) PC by 5 min ischemia-5 min reoxygenation before 90 min ischemia-120 min reoxygenation and (iv) CT-1 (1 nM) - 90 min ischemia-120 min reoxygenation with exposure to CT-1 throughout the protocol. In study 2, muscles (n=6/group) were allocated to one of four protocols as in study 1with the exception that were incubated for 24 h followed by 30 or 90 min ischemia-120 min reoxygenation on day 2. In study 3, the same groups were employed as in study 2 with the exception that only a 30-min period of ischemia was used and that CT-1 antibody (5 microg/ml) was added to all groups throughout the experimental protocol. Creatine kinase (CK, U/g wet wt.) leakage into the medium and MTT reduction (OD/mg wet wt.), an index of cell viability, were assessed at the end of the experiment. RESULTS: In study 1, a first window of cardioprotection was observed with PC (CK=4.39+/-0.34; MTT=0.58+/-0.03 vs. CK=7.11+/-0.4;MTT=0.32+/-0.02 in the ischemic alone group; P<0.001) but not with CT-1(CK=6.65+/-0. 67; MTT=0.31+/-0.03, P=NS vs. ischemia alone). In study 2, PC applied on day 1 was protective against 30-min ischemia (CK=3.28+/-0. 43; MTT=0.68+/-0.046, P<0.001 vs. ischemia alone) but not against 90-min ischemia (CK=7.13+/-0.66; MTT=0.24+/-0.03, P=NS vs. ischemia alone) induced on day 2 (second window). However, when the tissue was exposed to CT-1 for 24 h, protection was similar to that of PC when subjected to 30 min of ischemia (CK=2.95+/-0.71; MTT=0.77+/-0. 05, P=NS vs. PC) and greater than PC when subjected to 90 min of ischemia (CK=4.56+/-0.51; MTT=0.39+/-0.03, P=0.002 vs. PC). In study 3, the CT-1 antibody did not affect the protection induced by PC (CK=3.36+/-0.6; MTT=0.69+/-0.06) but it abolished the protection obtained with CT-1(CK=5.15+/-0.81; MTT=0.42+/-0.06, P=NS vs. ischemia alone group). CONCLUSIONS: CT-1 exhibits a significant protection of the human myocardium against ischemic injury when tissue is exposed to this factor for a long period (e.g. 24 h) but not when exposed for a short period (e.g. 2 h). In addition, the protection afforded by long exposure to CT-1 is as potent or even greater than the one obtained by the second window of PC. The protection induced by CT-1 but not that induced by PC can be abolished by CT-1 antibody suggesting that their beneficial action is attained by different mechanisms.

Adult↗
PubMed2000

The effect of valvular regurgitation on plasma Cardiotrophin-1 in patients with normal left ventricular systolic function.

BACKGROUND: Cardiotrophin-1 (CT-1), a member of the interleukin-6 related cytokine family that act via the gp130 signalling pathway, has been shown to stimulate the assembly of sarcomeric units in series in cardiomyocytes resulting in eccentric hypertrophy, ventricular dilatation and finally loss of function. In situations of volume overload a similar form of eccentric hypertrophy occurs with time. AIMS: We hypothesised that plasma CT-1 would be raised in patients with significant mitral, tricuspid and/or aortic regurgitation (MR/TR or AR, respectively) when compared to those with no (or mild) valvular regurgitant lesion. METHODS: A novel competitive immunoluminometric assay using an in-house polyclonal antibody to amino acids 105-120 of the CT-1 sequence was developed. Seventy-eight patients (31 male, mean+/-S.D. age 63.5+/-17.9 years), all with normal left ventricular systolic function were studied. Results are expressed as mean+/-S.D. fmol/ml. RESULTS: Sixty-three subjects had no significant valvular lesion, seven had moderate/severe MR, nine had moderate/severe TR and four had moderate/severe AR. These subjects had CT-1 concentrations of 53. 3+/-23.2, 90.5+/-44.4, 72.6+/-43.8 and 48.4+/-24.4, respectively (P=0.02, ANOVA). Mean log CT-1 was higher in those with moderate/severe MR when compared to those without a significant regurgitant valvular lesion (P<0.03). The only predictor of moderate/severe MR was log CT-1 (P=0.004). CONCLUSION: These results suggest that plasma CT-1 is raised in those patients with moderate/severe MR in the presence of normal left ventricular systolic function. This secretion of CT-1 could potentially be the cause of ventricular dilatation and subsequent loss of contractile function in these patients. It also offers the intriguing possibility that plasma CT-1 could be used to monitor progression of mitral regurgitation biochemically.

Aortic Valve Insufficiency↗