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Biomedical subjects

A Shankar

Publications and source records attributed to A Shankar.

At least 19 recordsLinked to original sources
PubMed2006

The association between serum uric acid level and long-term incidence of hypertension: Population-based cohort study.

Increasing experimental evidence, including recently developed animal models support a causal role for uric acid in the development of hypertension. However, it is not clear whether serum uric acid levels are independently associated with the long-term incidence of hypertension. We examined the association between serum uric acid levels and 10-year incidence of hypertension in a population-based cohort study based in Beaver Dam city and township, Wisconsin, US. We studied 2520 hypertension-free individuals (56.3% women, age: 43-84 years, 98% Caucasian) at the baseline examination (1988-1990). The main outcome of interest was hypertension (systolic blood pressure (BP) of 140 mm Hg or higher, diastolic BP 90 mm Hg or higher, or combination of self-reported high BP diagnosis and use of antihypertensive medications) incidence over 10 years among baseline normotensive individuals. Nine hundred and fifty-six individuals developed hypertension over a 10-year follow-up period. The relative risk (RR) (95% confidence intervals (CI)) of incident hypertension increased in a dose-dependent manner (P-trend < 0.05 in all models) with increasing uric acid quartiles. Multivariable RR (95% CI) comparing the highest quartile of serum uric acid (> or =390 micromol/l) to the lowest quartile (< or =260 micromol/l) was 1.65 (1.41-1.93). This association persisted in subgroup analyses by categories of smoking, alcohol intake, body mass index, baseline blood pressure and estimated glomerular filtration rate (GFR). In conclusion, increasing quartiles of serum uric acid was associated with 10-year incidence of hypertension independent of smoking, alcohol intake and baseline kidney function suggesting an independent positive association between serum uric acid levels and hypertension development among community-dwelling older adults.

Adult↗
PubMed2006

Ethnicity-specific prevalences of refractive errors vary in Asian children in neighbouring Malaysia and Singapore.

AIM: To compare the prevalences of refractive errors in Malay, Chinese and Indian children in Malaysia and Singapore. METHODS: Children aged 7-9 years from three schools in the Singapore Cohort study of the Risk factors for Myopia (n = 1962) and similarly aged children from a random cluster sample in the metropolitan Kuala Lumpur area in the Malaysia Refractive Error Study in Children (n = 1752) were compared. Cycloplegic autorefraction was conducted in both countries. RESULTS: The prevalence of myopia (spherical equivalent of at least -0.5 diopters (D) in either eye) was higher in Singapore Malays (22.1%) than in Malays in Malaysia (9.2%; 95% confidence interval (CI) 11.2 to 14.7; p<0.001). Similarly, Singapore Chinese (40.1%) had higher prevalences than Malaysian Chinese (30.9%; 95% CI 1.5 to 16.9). Singapore Indians had a higher prevalence (34.1%) than Malaysian Indians (12.5%; 95% CI 17.4 to 25.9). The multivariate odds ratio of astigmatism (cylinder at least 0.75 D in either eye) in Singapore Malays compared with Malaysian Malays was 3.47 (95% CI 2.79 to 4.32). Ethnicity-specific hyperopia rates did not differ in Singapore and Malaysia. CONCLUSION: The ethnicity-specific prevalences of myopia in Singapore Malays, Chinese and Indians are higher than those in Malaysian Malays, Chinese and Indians. As Malays, Chinese and Indians in Malaysia have genetic make-up similar to that of Malays, Chinese and Indians in Singapore, environmental factors may contribute to the higher myopia rates.

Asian People↗
PubMed2006

Defining myopia using refractive error and uncorrected logMAR visual acuity >0.3 from 1334 Singapore school children ages 7-9 years.

AIM: To determine the association of spherical equivalent (SE) with low uncorrected visual acuity (VA) along with a proposed definition for myopia using logMAR VA >0.3 as the criteria. METHODS: 1334 Chinese schoolchildren (mean age 7.8; range 7-9 years) were enrolled in the study after those who had hyperopia > or =+2.00 dioptres (D) and astigmatism > = -2.00 D were excluded. Uncorrected logMAR VA was measured for both eyes. Cycloplegia autorefraction was achieved by the instillation of three drops of 1% cyclopentolate 5 minutes apart. The average of five successful consecutive refraction and keratometry readings were obtained with calibrated Canon RK5 autokeratorefractometers by well trained optometry students, at least 30 minutes after the instillation of the third drop of cyclopentolate. SE cut-off points (-0.25 D, -0.5D, -0.75 D, -1.0 D) were evaluated. RESULTS: Using different SE cut-off points, the myopia prevalence rates of this sample of schoolchildren varied from 45.8% (SE at least -0.25 D) to 30.7% (SE at least -1.0 D). The cut-off point of > or =-0.75 D had a sensitivity and specificity of 91.8% (95% CI, 89.2 to 94.4) and 93.7% (95% CI, 92.1 to 95.3), respectively, to predict low vision defined as uncorrected logMAR VA > 0.3 (either eye). The next best cut-off point of -0.5D had a higher sensitivity (93.3%), but lower specificity (87.9%). CONCLUSIONS: The cut-off points of -0.75D and -0.5D in SE refraction are appropriate for the prediction of uncorrected logMAR VA worse than 0.3, which is the criterion for the US common state adult driver licensing standard.

Child↗
PubMed2005

Neurodevelopmental, functional and growth status of term low birth weight infants at eighteen months.

This study was done to evaluate the neurodevelopmental, functional and growth status of term infants weighing 2000 g or less at 18 months, and to analyze major medical and social factors associated with an adverse neurodevelopmental and/or functional outcome. All infants were assessed for growth, audio-visual, neurological impairment, and motor and mental development using Indian modification of Bayley Scales of infant development. A detailed history was also taken. Term infants with birth weight of >2500 g without any antenatal or neonatal complications served as controls. Fifty low birth weight (LBW) term infants and 30 controls were evaluated. The mean mental development Quotient for LBW infants [91.51(16.97)] was significantly lower than that of Controls [102.02(8.4)]; the mean motor development Quotient however was comparable. The LBW infants were significantly lagging in terms of weight, length and head circumference at assessment. Neonatal complications were associated with an abnormal motor outcome while lower Socio-economic status and maternal education were related to adverse mental status. We concluded that Term LBW infants are at a significant disadvantage in terms of growth and mental scores at 18 months.

Child Development↗
PubMed2004

Intratumoral abscess: an unusual complication of ventriculoperitoneal shunt infection.

INTRODUCTION: Ventriculoperitoneal shunts were routinely used in the past in children with posterior fossa tumors and hydrocephalus. They can, however, cause a multitude of problems. CASE REPORT: This report highlights a previously unencountered phenomenon of a pyogenic abscess forming within a posterior fossa ependymoma as a result of shunt infection. The shunt was exteriorized and the child treated with antibiotics before surgery was done. Only a partial excision of the tumor was possible, as the inflammatory response caused by the abscess had obliterated tissue planes.

Amikacin↗
PubMed2004

Pylorus-preserving pancreaticoduodenectomy for advanced duodenal disease in familial adenomatous polyposis.

BACKGROUND: Although only 5 per cent of patients with familial adenomatous polyposis (FAP) die from duodenal cancer, a recent study indicated that the mortality rate is much higher in patients with Spigelman stage IV disease. This has prompted an increased rate of referral for excisional surgery and an analysis of the results. METHODS: Between January 1994 and June 2002, 16 patients with FAP (mean age 55 years; eight men) were referred to a single surgeon for pylorus-preserving pancreaticoduodenal resection for Spigelman stage IV duodenal adenomatosis. RESULTS: One patient died from multiple organ failure after relaparotomy for haemorrhage and a jejunal perforation; other major complications included anastomotic leak (one), primary haemorrhage (one), lymphatic leak (one), chylous ascites (one), pulmonary embolus (two) and prolonged delayed gastric emptying that required total parenteral nutrition (three). Overall there were 11 major complications in eight patients. Two patients developed insulin-dependent diabetes and one postprandial dumping. Postoperative histological examination revealed five unsuspected cancers, which led to four deaths within 3 years of surgery. One patient died 2 months after surgery from pulmonary thromboembolism and another at 5 months from an inoperable brain tumour. Nine of the 16 patients were alive and well at a mean of 38 months after surgery. CONCLUSION: The choice between continued endoscopic surveillance and excisional surgery for Spigelman stage IV duodenal disease remains finely balanced.

Adenomatous Polyposis Coli↗
PubMed2003

Interhemispheric subdural hematoma: an uncommon sequel of trauma.

Interhemispheric subdural hematomas are relatively uncommon and usually seen in patients with bleeding disorders. They may present with signs of the falx syndrome or seizures. The management options range from craniotomy and evacuation to conservative management. We report such a case in a patient with normal bleeding parameters, which was managed with a twist drill craniostomy and drainage of the hematoma.

Aged↗
PubMed2003

Radiological and clinical outcome following stereotactic biopsy and radiotherapy for low-grade insular astrocytomas.

Thirty patients with low-grade (WHO Grade II) astrocytomas involving the insula, who had undergone stereotactic biopsy followed by radiotherapy, were followed up to evaluate the outcome with regard to control of seizures, memory and language function, Karnofsky Performance scale and regression in tumor volume. Patients were followed up for a mean of 27.8 months, during which time they showed improvement in all the factors that were studied. A statistically significant change was, however, seen only in the reduction in tumor size, probably due to the small sample size and the short duration of follow-up. Stereotactic biopsy followed by radiation therapy provides a good short-term outcome in patients with low-grade insular astrocytomas.

Adult↗
PubMed2002

A randomised study of prophylactic G-CSF following MRC UKALL XI intensification regimen in childhood ALL and T-NHL.

BACKGROUND: Despite the current widespread use of prophylactic G-CSF in children with solid tumours and leukaemia, its effectiveness has not been clearly demonstrated. This randomised study evaluates the role of G-CSF given after a 5-day intensification block in children with acute lymphoblastic leukaemia (ALL). PROCEDURE: Forty-six children with ALL or T-Cell non-Hodgkins lymphoma (NHL) treated on MRC ALL 97, UKALL XI or UKCCSG 9504 NHL protocols were randomised to receive granulocyte colony-stimulating factor following either the first or the second block of intensive chemotherapy in a cross-over study to determine if the prophylactic administration of G-CSF could reduce the rate of readmission to hospital for management of febrile neutropenia. RESULTS: There was a statistically significant difference in the rate of hospital admission in the group receiving prophylaxis, with 34 of 46 being admitted, compared to 42 of 46 patients in the control arm (74 vs. 91%; P=0.0386). There were no differences found in duration of hospital admission, haematological toxicity, neutrophil recovery or duration of supportive care between the two groups. There was no demonstrable cost benefit derived from the prophylactic administration of G-CSF. CONCLUSIONS: This study shows that the prophylactic administration of G-CSF following intensification chemotherapy for childhood ALL and T-NHL produces a significant reduction in the rate of readmission to hospital for the management of febrile neutropenia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

Heterotopic ossification in the orbit.

BACKGROUND: While calcification of orbital hemangiomas has been reported previously, no reports exist of heterotopic ossifications occurring within the orbit. CASE DESCRIPTION: A 30-year-old male presented with spontaneous onset of painless progressive proptosis of the left eye, with diplopia. The preoperative radiologic findings are presented. The lesion was excised completely. The pathologic features and probable causes are discussed. CONCLUSIONS: Heterotopic ossification of the orbit should be considered in the differential diagnosis of an orbital lesion showing radiologic features of calcification or ossification.

Adult↗
PubMed2002

Autosomal recessive limb girdle myasthenia in two sisters.

Limb girdle myasthenic syndromes are rare genetic disorders described under the broad heterogeneous group known as congenital myasthenic syndromes and present with mixed features of myasthenia and myopathy. The familial limb girdle myasthenia has been described as one with selective weakness of pectoral and pelvic girdles, showing a positive response to edrophonium chloride. A report of two sisters affected by this disorder is presented.

Adolescent↗
PubMed2001

Increased endothelin-1 in colorectal cancer and reduction of tumour growth by ET(A) receptor antagonism.

Endothelin-1 (ET-1) is a vasoconstrictor peptide which stimulates proliferation in vitro in different cell types, including colorectal cancer cells. Raised ET-1 levels have been detected both on tissue specimens and in the plasma of patients with cancers. To investigate the role of ET-1 in colorectal cancer: (i) ET-1 plasma levels in patients with colorectal cancer were measured by radioimmunoassay: group 1 = controls (n = 22), group 2 = primary colorectal cancer only (n = 39), group 3 = liver metastases only (n = 26); (ii) ET-1 expression in primary colorectal cancer specimens (n =10) was determined immunohistochemically and (iii) the effect of intraportally infused antagonists to the two ET-1 receptors, ET(A) and ET(B), on the growth of liver metastases in a rat model was assessed. ET-1 plasma levels were significantly increased in both patients with primary tumour and patients with metastases, compared to controls (P < 0.01, 3.9 +/- 1.4, 4.5 +/- 1.5, vs. 2.75 +/- 1.37 pg/ml, respectively). Immunohistochemically, strong expression of ET-1 was found in the cytoplasm, stroma and blood vessels of cancers, unlike the normal colon where only the apical layer of the epithelium, vascular endothelial cells and surrounding stroma were positively stained. In the rat model, there was significant reduction in liver tumour weights compared to controls, following treatment with the ET(A) antagonist (BQ123) 30 min after the intraportal inoculation of tumour cells (P < 0.05). These results suggest ET-1 is produced by colorectal cancers and may play a role in the growth of colorectal cancer acting through ET(A) receptors. ET(A) antagonists are indicated as potential anti-cancer agents.

Adult↗
PubMed2001

Identification and molecular characterisation of a CALM-AF10 fusion in acute megakaryoblastic leukaemia.

The t(10;11)(p13;q14-21) is a non-random translocation described in acute lymphoblastic and myeloid leukaemias. It results in the fusion of the gene CALM, which encodes a clathrin assembly protein, on 11q14 to the gene AF10, a putative transcription factor on 10p13. Here we describe for the first time, the occurrence of a CALM-AF10 fusion in a case of acute megakaryoblastic leukaemia. Fluorescence in situ hybridisation and reverse transcriptase polymerase chain reaction were used to confirm the presence of a CALM-AF10 fusion. A novel splice variant of CALM missing nt 1927-2091 was also detected. Though CALM is a cytoplasmic protein, the chimaeric fusion product is able to localise to both the nucleus and cytoplasm. Analysis of the fusion variants suggests, however, that the critical fusion product is likely to be cytoplasmic and contain the interactive leucine zipper of AF10.

Active Transport, Cell Nucleus↗
PubMed2001

Neo-adjuvant therapy improves resectability rates for colorectal liver metastases.

PURPOSE: Liver resection improves survival in selected patients with colorectal liver metastases. However, the majority of patients with colorectal liver metastases have inoperable disease at presentation. Neo-adjuvant therapy (systemic or regional chemotherapy and interstitial laser therapy) used singly or in combination may convert a selected group of patients with irresectable liver metastases into an operable state. PATIENTS AND METHODS: We report a series of patients with initially inoperable multiple colorectal liver metastases who became operable after neo-adjuvant therapy. Operability was defined as unilateral disease limited to the liver. Twelve patients (7 female, 5 male, median age 57 years, range 38-69 years) with multiple inoperable colorectal liver metastases (8 synchronous, 4 metachronous) were initially treated with systemic chemotherapy (n = 7), hepatic arterial chemotherapy (n = 2) and chemotherapy plus interstitial laser therapy (n = 3). RESULTS: In all cases, a significant response was achieved which enabled subsequent liver resection to be undertaken. There was only one postoperative complication (8%) and no peri-operative deaths. 3 patients were operated on within the last 12 months and are still alive. Of the remainder, 1 died within 1 year with recurrent disease. The remaining patients have a median survival of 2.5 years, range 1.39-4 years. CONCLUSIONS: These results are similar to those reported for patients undergoing resection for operable metastases without neo-adjuvant therapy. Aggressive multimodality treatment of colorectal liver metastases in specialised centres may improve the resectability rates and survival in a selected group of patients.

Adult↗
PubMed2000

Catheter mapping of spontaneous and induced atrial fibrillation in man.

The clinical electrophysiologic study of atrial fibrillation [AF] has recently progressed from static characterization of the substrate to the dynamic investigation of both induced and spontaneous AF in man. Prior studies have demonstrated inhomogeneity and greater dispersion of atrial refractoriness in patients with AF, but recently atrial electrical remodeling with consequent abbreviation of atrial refractory periods has also been reported. Yet further experimental observations have suggested the existence of additional arrhythmogenic mechanisms for certain AF subsets. These include studies that have demonstrated a stable atrial flutter circuit in one atrium with fibrillatory conduction or a focal atrial tachyarrhythmia arising commonly in the left atrium. Efforts at catheter mapping of AF are now in progress. New mapping techniques and novel devices are currently being employed. We have performed catheter mapping simultaneously in right and left atrial sites at onset and during sustained pacing-induced and spontaneous AF in patients with ischemic and/or hypertensive heart disease. Atrial premature complexes that initiated spontaneous AF typically had coupling intervals ranging from 260 to 400 ms and most frequently arose in the crista terminalis, right atrioventricular junction or superior left atrium. AF at onset showed discrete electrograms at virtually all right and left atrial regions mapped and the region of earliest atrial activation during AF was in close proximity to the premature complexes in over 90% of patients. The regional atrial activation sequence for the first 10 AF beats demonstrated stable or unstable patterns in individual patients. In contrast to spontaneous AF, the initial arrhythmia of induced AF was seen to have a significantly different site of earliest atrial activation but similar discrete electrograms in different atrial regions. However, as with spontaneous AF, the site of extrastimulus delivery was in close proximity to the first induced beat. We conclude that regional catheter mapping of AF is feasible and safe in man and organized electrical activity is frequently observed at AF onset in patients with heart disease. Both right and left atrial regions can be the source of atrial premature complexes and at the onset of spontaneous AF. Induced AF may have differing activation patterns than spontaneous AF but both demonstrate earliest activation in proximity to the initiating atrial premature complex. These findings may help explain therapeutic benefits of right and left atrial interventions and pacing therapies in AF.

Atrial Fibrillation↗
PubMed2000

Treatment of recurrent colorectal liver metastases by interstitial laser photocoagulation.

BACKGROUND: Hepatic resection improves survival in selected patients with colorectal liver metastases. The treatment of recurrent hepatic metastases after resection is controversial. Interstitial laser photocoagulation, performed under local anaesthesia, offers a minimally invasive option to repeat resection. The first series of patients with recurrent colorectal liver metastases treated with photo- coagulation is reported. METHODS: Nineteen patients (five women and 14 men, median age 57 (range 44-71) years) who developed recurrent colorectal liver metastases after hepatectomy (five with bilateral disease) were treated with photocoagulation between 1993 and 1997. Fifteen patients also received chemotherapy (14 systemic, one hepatic arterial) before photocoagulation. RESULTS: There were no major complications or deaths related to the treatment. Six patients developed minor complications related to the procedure but did not require any form of intervention. Median survival from commencement of photocoagulation was 16 (range 4-36) months. CONCLUSION: Photocoagulation is a safe, minimally invasive therapy that may be used as an adjunct to chemotherapy and repeat resection in the treatment of recurrent colorectal liver metastases, and may lead to improved survival.

Adult↗