Biomedical subjects

A Patel

Publications and source records attributed to A Patel.

At least 19 recordsLinked to original sources

PubMed2006

A novel 8.5 MB dup(1)(p34.1p34.3) characterized by FISH in a child presenting with congenital heart defect and dysmorphic features.

Chromosome duplications involving 1p are rarely reported but are apparently associated with short survival as well as congenital malformations and impaired development. Several of these have had congenital heart defects, although too few patients have been reported with similar breakpoints to characterize a syndrome. We present a girl with a novel interstitial duplication in the short arm of chromosome 1 [46,XX,dup(1)(p34.1p34.3)]. She presented with congenital heart defects at 1 month and by 1 year of age manifested delayed acquisition of motor milestones and subsequently of language milestones. By breakpoint-mapping using FISH analysis, we determined that her 1p duplication spans 8.5 megabases. Her 1p duplication is the smallest reported to date to contain 1p34 in patients with congenital heart defect due to abnormalities of heart looping during development. Thus, her 8.5 MB duplication provides a target region to search for a potentially dosage-sensitive gene(s) causing abnormal heart looping when duplicated. Two patients have been reported with duplication including 1p34 but without congenital heart defect, and their duplications span all but the distal approximately 2 MB segment duplicated in our patient. Thus, within our patient's 8.5 MB target region for a dosage sensitive gene leading to looping abnormalities (and thereby congenital heart defect), the distal 2 MB region might well be the region to begin the search.

Child, Preschool↗

PubMed2006

WAGR(O?) syndrome and congenital ptosis caused by an unbalanced t(11;15)(p13;p11.2)dn demonstrating a 7 megabase deletion by FISH.

Aniridia usually occurs in isolation, but may also occur as part of the WAGR contiguous gene deletion syndrome, which includes Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation. The aniridia and predisposition for Wilms tumor seen in WAGR are caused by haploinsufficiency for PAX 6 and WT1, respectively. We present a female infant with aniridia, bilateral ptosis, bilateral posterior capsular cataracts, nystagmus, left-sided glaucoma, microcephaly, mild unilateral hydronephrosis, poor linear growth, and gross motor delay consistent with a clinical diagnosis of WAGR syndrome. In addition, weight-for-height ratio at 12 months is at the 94th centile, raising the possibility of a diagnosis of WAGRO (WAGR + Obesity). Chromosome analysis revealed a translocation (11;15)(p13;p11.2) which has not been previously associated with a diagnosis of WAGR. Subsequent clinical WAGR fluorescent in situ hybridization (FISH) analysis demonstrated a deletion of 11p13 including PAX6 and WT1. A complete FISH-mapping of the breakpoints on chromosome 11 revealed a 7 Mb deletion within 11p13-11p14. The patient is examined in light of other reported patients with deletions and/or translocations involving the regions between 11p12 --> 11p14 including patients with WAGR + obesity (WAGRO) as well as with other reported patients with aniridia and congenital ptosis.

Abnormalities, Multiple↗

PubMed2006

Array-based comparative genomic hybridization facilitates identification of breakpoints of a novel der(1)t(1;18)(p36.3;q23)dn in a child presenting with mental retardation.

Monosomy of distal 1p36 represents the most common terminal deletion in humans and results in one of the most frequently diagnosed mental retardation syndromes. This deletion is considered a contiguous gene deletion syndrome, and has been shown to vary in deletion sizes that contribute to the spectrum of phenotypic anomalies seen in patients with monosomy 1p36. We report on an 8-year-old female with characteristics of the monosomy 1p36 syndrome who demonstrated a novel der(1)t(1;18)(p36.3;q23). Initial G-banded karyotype analysis revealed a deleted chromosome 1, with a breakpoint within 1p36.3. Subsequent FISH and array-based comparative genomic hybridization not only confirmed and partially characterized the deletion of chromosome 1p36.3, but also uncovered distal trisomy for 18q23. In this patient, the duplicated 18q23 is translocated onto the deleted 1p36.3 region, suggesting telomere capture. Molecular characterization of this novel der(1)t(1;18)(p36.3;q23), guided by our clinical array-comparative genomic hybridization, demonstrated a 3.2 Mb terminal deletion of chromosome 1p36.3 and a 200 kb duplication of 18q23 onto the deleted 1p36.3, presumably stabilizing the deleted chromosome 1. DNA sequence analysis around the breakpoints demonstrated no homology, and therefore this telomere capture of distal 18q is apparently the result of a non-homologous recombination. Partial trisomy for 18q23 has not been previously reported. The importance of mapping the breakpoints of all balanced and unbalanced translocations found in the clinical laboratory, when phenotypic abnormalities are found, is discussed.

Child↗

PubMed2006

An evaluation of metabolic risks for coronary death in the Asia Pacific region.

AIM: To investigate the generalizability of current definitions of the metabolic syndrome in Asia-Pacific populations, and whether information on metabolic risk factors could be better used to discriminate fatal coronary heart disease (CHD) risk. METHODS AND RESULTS: Analyses were performed on individual participant data from 26 cohorts involving 329, 166 participants from the Asia Pacific region. Sensitivity and specificity estimates for CHD death associated with cut-points as defined by the U.S. National Cholesterol Education Panel (NCEP) were determined for component risk factors of a modified NCEP-defined metabolic syndrome. Five cohorts (6437 subjects, 53 CHD deaths) measuring all five risk factors at baseline were used to evaluate the association between the metabolic syndrome and CHD, and to compare risk discrimination using a definition including each risk factor as a continuous variable. Sensitivity and specificity estimates for risk factor cut-points varied considerably by region (Asia versus Australia/New Zealand) and moderately by sex. The adjusted hazard ratio for CHD death associated with the modified NCEP-defined metabolic syndrome was 2.05 (95%CI, 1.13-3.72). On receiver operator characteristic analysis, the area-under-the-curve for CHD death was 0.586 (95%CI: 0.439-0.732) for the modified NCEP-defined metabolic syndrome, and 0.733, 95%CI: 0.664-0.802) for a definition including each of the metabolic risk factors in their continuous form. CONCLUSION: Specific cut-points for metabolic risk factors are not generalizable between populations. This finding is not restricted to measures of central obesity. A multivariable definition of the metabolic syndrome including all risk factors as continuous variables improves CHD risk discrimination substantially.

Adult↗

PubMed2006

Drape estimation vs. visual assessment for estimating postpartum hemorrhage.

OBJECTIVE: To compare (1) visual estimation of postpartum blood loss with estimation using a specifically designed blood collection drape and (2) the drape estimate with a measurement of blood loss by photospectrometry. METHODS: A randomized controlled study was performed with 123 women delivered at the District Hospital, Belgaum, India. The women were randomized to visual or drape estimation of blood loss. A subsample of 10 drape estimates was compared with photospectrometry results. RESULTS: The visual estimate of blood loss was 33% less than the drape estimate. The interclass correlation of the drape estimate to photospectrometry measurement was 0.92. CONCLUSION: Drape estimation of blood loss is more accurate than visual estimation and may have particular utility in the developing world. Prompt detection of postpartum hemorrhage may reduce maternal morbidity and mortality in low-resource settings.

Delivery, Obstetric↗

PubMed2006

Raised troponin T and echocardiographic abnormalities after prolonged strenuous exercise--the Australian Ironman Triathlon.

BACKGROUND: There is concern about whether cardiac damage occurs as a result of prolonged strenuous exercise. OBJECTIVE: To investigate whether competing in a triathlon is associated with cardiac damage based on a sustained increase in cardiac troponin T (cTnT), and whether such an increase correlates with echocardiographic changes METHODS: cTnT and echocardiographic measurements were made in 38 participants in the 2001 Australian ironman triathlon. cTnT was measured the day before, immediately after, and the day following the race. Echocardiography was done the day before, immediately after, and two to six weeks later for measurement of ejection fraction, stroke volume, cardiac output, wall motion analysis, and global left ventricular function (LVF). RESULTS: No subject had detectable cTnT in the pre-race sample. Following the race, 32 subjects (86.5%) had detectable levels of cTnT (>0.01 ng/ml), with six (16.2%) having >0.10 ng/ml. The day after the race, nine subjects (23.7%) still had detectable cTnT, with two recording a level >0.10 ng/ml. Previously described echocardiographic changes of "cardiac fatigue" were observed in the whole cohort. There was a modest but significant correlation between change in ejection fraction and peak cTnT level (p = 0.02, r = 0.39). Athletes with a post-race cTnT >0.10 ng/ml had a greater decrease in global LVF (p = 0.02) and a trend toward a greater fall in ejection fraction and stroke volume than athletes with cTnT levels <0.10 ng/ml. Cardiac output fell in the group with cTnT >0.10 ng/ml (p>0.05). CONCLUSIONS: Participation in ironman triathlon often resulted in persistently raised cTnT levels, and the troponin rise was associated with echocardiographic evidence of abnormal left ventricular function. The clinical significance and long term sequelae of such damage remains to be determined.

Adult↗

PubMed2006

Erythropoietin in thyroid cancer.

Erythropoietin (Epo) and the epo-receptor (EpoR) have been implicated in tumor growth, invasion and metastasis. We previously demonstrated Epo and EpoR expression in a small group of archived papillary thyroid cancers (PTC), but were unable to examine functional integrity using formalin-fixed tissues. In the present study, we examined the in vitro expression, induction and function of Epo and EpoR in papillary (NPA), follicular (WRO) and anaplastic (ARO-81) thyroid cancer cells. We found that all three cell lines expressed Epo and EpoR mRNA and that the hypoxia-mimetic cobalt induced Epo expression in all cell lines. None of the growth factors we examined (thyrotropin, vascular endothelial growth factor, IGF-I, or human Epo) altered Epo or EpoR gene expression. Importantly, however, administration of Epo to NPA but not WRO cells resulted in significant alterations in the expression of several mitogenic genes including cyclooxygenase-2 (COX-2), beta-casein (CSN2), wild type p53-induced gene-1 (WIG1) and cathepsin D (CTSD). Epo treated ARO-81 cells only had an increase in CSN2 expression. We conclude that Epo and EpoR are expressed by thyroid cancers and that stimulation of the Epo/EpoR signal pathway results in changes that could impact on the clinical behavior of thyroid cancers.

Carrier Proteins↗

PubMed2006

Investigation of silica-iron-phosphate glasses for tissue engineering.

Phosphate-based glasses have previously been examined for tissue engineering applications, however they degrade rapidly in solution reducing its pH to below 5. This study presents a series of phosphate-based glass compositions that degrade at a lower rate, allowing the pH to remain close to neutral in cell culture medium. The compositions investigated were P50Ca30Na(15-x)Fe5Si(x) where x = 0, 1, 3 and 5 mol%. The dissolution and effect on pH in distilled water and cell culture medium, and ion release in distilled water were investigated over 7 days and MG63 cell attachment to glass fibres was observed after 24 hrs. Dissolution was much slower in cell culture medium (3% mass loss) compared to distilled water (50% mass loss), due to the large quantity of ions and pH buffer present. After 7 days, in cell culture medium the pH remained between 7 and 8.5, however the pH in distilled water fell to between 4 and 3, with the final pH being lower the greater the SiO2 content. Increasing the SiO2 content of the glass resulted in an increase in dissolution rate whilst the pH was maintained at 7 in cell culture medium. The attachment and spreading of MG63 cells was observed on all compositions. These glass compositions may therefore be suitable for tissue engineering applications.

Biocompatible Materials↗

PubMed2006

Brn-3a neuronal transcription factor functional expression in human prostate cancer.

Neuroendocrine differentiation has been associated with prostate cancer (CaP). Brn-3a (short isoform) and Brn-3c, transcriptional controllers of neuronal differentiation, were readily detectable in human CaP both in vitro and in vivo. Brn-3a expression, but not Brn-3c, was significantly upregulated in >50% of tumours. Furthermore, overexpression of this transcription factor in vitro (i) potentiated CaP cell growth and (ii) regulated the expression of a neuronal gene, the Nav1.7 sodium channel, concomitantly upregulated in human CaP, in an isoform-specific manner. It is concluded that targeting Brn-3a could be a useful strategy for controlling the expression of multiple genes that promote CaP.

Blotting, Western↗

PubMed2006

Cause of upper urinary-tract essential hematuria: Veno-caliceal fistula or contralateral coexistent upper-tract transitional-cell carcinoma? Case report.

A 65-year-old woman was admitted with intermittent gross hematuria of 6 months' duration without other significant urinary-tract symptoms. At bilateral ureterorenoscopy under general anesthesia, a connection from an upper calix to the main left renal vein through a small venous channel was apparent, but there was no evidence of bleeding. In the right upper calix, a bleeding small papillary lesion was seen and ablated with low-power thulium laser coagulation. The histologic examination revealed a grade 3 stage pT1 TCC. Where no definite bleeding is seen from a veno-caliceal fistulous opening at ureterorenoscopy, it is imperative to inspect the entire contralateral upper urinary tract to exclude other causes of bleeding.

Aged↗

PubMed2006

Objective sizing of upper airway stenosis: a quantitative endoscopic approach.

OBJECTIVE: In patients with airway stenosis, anatomy of the lesion determines the magnitude of the biomechanical ventilatory disturbance and thus the nature and severity of symptoms. It also gives information about biology, likelihood of response to treatment, and prognosis of laryngotracheal lesions. Accurate airway sizing throughout treatment is therefore central to managing this condition. We developed a method for objective assessment of airway lesions during endoscopy. METHODS: We used airway simulations to investigate the effects of endoscope tilt and lens distortions on measurement accuracy, devising and validating clinical rules for quantitative airway endoscopy. A calibrator was designed to assess lesion length, location, and cross-section during tracheoscopy. RESULTS: It proved possible to calculate the length and location of the stenosis using simple mathematics. Cross-section measurements were more than 95% accurate, independent of endoscope tilt and without making assumptions about endoscope optics and visuospatial distortion, for both pediatric and adult airway dimensions. The technique was used to characterize airway lesions in 10 adult patients with an average age of 48 years undergoing therapeutic laryngotracheoscopy. Lesions occurred on average 36 mm below the glottis (range, 21-54 mm) and were 9.3 mm long (5-17 mm). The average pretreatment airway cross-section was 48.3 mm, increasing to 141.1 mm after laser therapy. Two independent observers calculated airway cross-sections, achieving an interobserver concordance of 0.98. CONCLUSIONS: This method can be used to objectively and precisely determine the anatomy of airway lesions, allowing accurate documentation of lesion characteristics and surgical results, serial monitoring throughout treatment, and comparison of outcomes between different centers.

Adult↗

PubMed2006

Determinants of compliance with colonoscopy in patients with adenomatous colon polyps in a veteran population.

AIM: To determine factors affecting compliance of a follow-up colonoscopy in patients with previously diagnosed adenomatous colon polyps. METHODS: A retrospective review was performed on patients with adenomatous polyps excised between January and December 1998. Twenty-nine clinical factors were assessed in patients grouped into whether they were compliant (n = 81) or noncompliant (n = 38) with follow-up colonoscopy. Significant variables by univariate analysis were included in multivariate regression. RESULTS: One hundred and nineteen patients with adenomatous colon polyps were identified. Of 119 patients, 114 had a documented recommendation for follow-up of 5 years or less, with 69% having been compliant. In a univariate analysis, greater number of polyps (P = 0.04), NSAID use (P = 0.02), statin use (P = 0.005), first-degree relatives with colon cancer (P = 0.05) and compliance with out-patient clinic follow-up (P < 0.001) were significantly associated with patient compliance. Multivariate analysis revealed statin use (P = 0.05), first-degree relatives with colon cancer (P = 0.06) and compliance with out-patient clinic follow-up (P < 0.001) were independent predictors of compliance. CONCLUSIONS: History of statin use and family history of colon cancer are good predictors of compliance. The strongest predictor can be anticipated with compliance assessed with encounters for other visits. Strong efforts should be directed at improving patient education about colon cancer by the physician and facilitating patient compliance.

Adenomatous Polyps↗

PubMed2006

A comparison of two single dilator percutaneous tracheostomy sets: the Blue Rhino and the Ultraperc.

The single tapered dilator kit is the most commonly used percutaneous tracheostomy set in the UK. The Cook Blue Rhino and the Portex Ultraperc were compared in the laboratory on mannequin and porcine airway models. The following data were collected: the subjective ease of dilating the trachea and inserting the tracheostomy tube; the time taken and the anterior-posterior compression during dilatation and tube insertion; the incidence and extent of posterior tracheal wall damage. During dilatation, the Blue Rhino caused less mean percentage anterior-posterior compression (34.8% vs. 51.5%, p = 0.0014). There was no difference in subjective ease or time for dilatation in either mannequin or porcine airway models. During insertion of the tracheostomy tube, the Ultraperc was subjectively easier in the porcine airway model (p = 0.001); had a shorter median insertion time in both the mannequin (3 s vs. 7.2 s, p = 0.0006) and the porcine airway model (4.3 s vs. 8.5 s, p = 0.0005); the mean percentage anterior-posterior compression caused was less in the mannequin (51.5% vs. 76%, p = 0.0008). The overall incidence of posterior wall damage was 65% with 25% having deep lacerations. There was no difference in the incidence of damage between the two sets. The Ultraperc therefore has advantages during tracheostomy tube insertion that are statistically and clinically significant. The advantages are probably due to the presence of the tracheostomy tube introducer.

Animals↗

PubMed2006

Mixed glioneuronal tumour of the fourth ventricle with prominent rosette formation.

We describe three unusual tumours characterized by a mixture of glial and neuronal differentiation, involvement of the posterior fossa and formation of rosettes. Mixed glial-neuronal tumours of the posterior fossa are rare and poorly described neoplasms. However, several distinctive entities have appeared in the literature over recent years under a variety of different names. Our cases demonstrate the morphological features of the 'rosette-forming glioneuronal tumour of the fourth ventricle', a recently identified tumour characterised by its unique location, neurocytic pseudo-rosette formation and the presence of a low grade astrocytoma component. The long term prognosis of these tumours remains unclear. However, the clinical data available including the cases presented here, along with the histological features, suggest that these are low grade tumours with a good prognosis after surgical resection.

Adult↗

PubMed2006

Effect of fat distribution on endothelial-dependent and endothelial-independent vasodilatation in healthy humans.

AIM: The present study aims to explore the relationship between inflammatory cytokines, plasma lipids, insulin, blood pressure (BP), total adiposity/markers of fat distribution and endothelial function in healthy people across a wide range of body fatness. METHODS: Seventy-three healthy people (44 women; age range: 24-64 years) with body mass index (BMI) range of 18.6-73.1 kg/m2 were recruited. All participants underwent assessment of conduit artery endothelial-dependent vasodilatation by using flow-mediated vasodilatation (FMD) of the brachial artery and endothelial-independent vasodilatation to sublingual GTN. They had blood taken for measurement of plasma markers of glucose homeostasis (fasting insulin and glucose), systemic inflammation (interleukin-6 (IL-6), C-reactive protein (CRP) and tumour necrosis factor-alpha receptor 2 (TNF-alpha R2)) and lipids (low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides). Morphometric assessment (waist circumference, BMI and waist-to-hip ratio (WHR)) and systolic and diastolic arterial pressure were also measured. RESULTS: Markers of total body fat/fat distribution (waist circumference, BMI and WHR), inflammation (IL-6, CRP and TNF-alpha R2), metabolism (fasting insulin, HDL, LDL and triglycerides) and BP (systolic and diastolic) correlated with FMD. Among these measurements, WHR was the only independent predictor of FMD (r2 = 0.30; p = 0.0001). CONCLUSIONS: WHR is an important marker of endothelial dysfunction in healthy people across a wide range of body fatness.

Adult↗

PubMed2006

MRI scanning and orthodontics.

Magnetic Resonance Imaging (MRI) plays an important role in diagnosis for many head and neck lesions. Both clinical and experimental studies have shown that orthodontic appliances may produce image distortion on MRI scans of the head and neck. A case is presented in which the patient complained of unexplained right-sided facial paraesthesia, whilst undergoing fixed appliance orthodontic treatment. This was a serious symptom, which warranted investigation including a MRI scan. The compatibility of fixed appliances with MRI is discussed.

Adolescent↗

PubMed2005

Is a single definition of the metabolic syndrome appropriate?--A comparative study of the USA and Asia.

The metabolic syndrome has been identified as an increasingly important precursor to cardiovascular diseases in many Asian populations. Our objective was to compare the contribution of component risk factors to the diagnosis of the metabolic syndrome, as defined by the Third report of the National Cholesterol Education Program Expert Panel Adult Treatment Panel (NCEP-ATPIII), in the US and selected Asian populations. Nationally representative survey data from Hong Kong, Taiwan, Thailand and the US were used. Analyses were restricted to men and women aged > or = 35 years. The age-standardized prevalence of the NCEP-ATPIII defined metabolic syndrome was highest in the US (31% in men, 35% in women), and lowest in Taiwan (11% in men, 12% in women). The component risk factors that defined the presence of the metabolic syndrome varied between countries. As expected, abnormal waist circumference was considerably more prevalent among individuals with the metabolic syndrome in the US (72% in men, 94% in women) compared with their Asian counterparts, but substantial variation was also observed between the Asian populations (13-22% in men, 38-63% in women). Furthermore, the relative contribution of other risk factors to the metabolic syndrome was also substantially different between countries. The NCEP-ATPIII definition identifies a heterogeneous group of individuals with the metabolic syndrome in different populations.

Blood Pressure↗

PubMed2005

Smoking, quitting, and the risk of cardiovascular disease among women and men in the Asia-Pacific region.

BACKGROUND: Although smoking is a major risk factor for cardiovascular disease, it has been suggested that Asians may be less susceptible to the adverse effects of smoking than Caucasians. This may have contributed to the high prevalence of smoking, and the low quitting rates, in Asian men. Worldwide, smoking rates are increasing for women, amongst whom cardiovascular awareness is relatively poor. METHODS: An individual participant data analysis of 40 cohort studies was carried out, involving 463 674 Asians (33% female) and 98 664 Australasians (45% female). Cox proportional hazard models, stratified by study and sex where appropriate, were employed. RESULTS: The HR [95% confidence interval (CI)], comparing current smokers with non-smokers, for coronary heart disease (CHD) was 1.60 (1.49-1.72); haemorrhagic stroke 1.19 (1.06-1.33); ischaemic stroke 1.38 (1.24-1.54). There was a clear dose-response relationship between the number of cigarettes smoked per day and both CHD and stroke, with no significant difference (P >/= 0.20) between populations from Asia and Australia/New Zealand. Although there was no sex difference for stroke in the effect of amount smoked (P = 0.16), for CHD, women tended to have higher hazard ratios than men (P = 0.011). Quitting gave a clear benefit, which was not significantly different between the sexes or regions (P > 0.63). The HR (CI) for ex-smokers compared with current smokers was 0.71 (0.64-0.78) for CHD and 0.84 (0.76-0.92) for stroke. CONCLUSIONS: Unless urgent public health measures are put into place, the impact of the smoking epidemic in Asia, and among women, will be enormous. Tobacco control policies that specifically target these populations are essential.

Adult↗