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Biomedical subjects

A Singhal

Publications and source records attributed to A Singhal.

At least 19 recordsLinked to original sources
PubMed2006

Cerebrospinal fluid (CSF) leak and pseudomeningocele formation after posterior fossa tumor resection in children: a retrospective analysis.

OBJECTIVE: The purpose of this study was to determine the incidence of pseudomeningocele and cerebrospinal fluid (CSF) leak after posterior fossa tumor surgery and to analyze factors that may be associated with these conditions. In particular, we wished to determine if there was evidence to support the hypothesis that the use of tissue glue, dural grafts, or external ventricular drainage (EVD) prevented CSF from leaking outside the closed dura. MATERIALS AND METHODS: A retrospective chart review was carried out of posterior fossa tumor resections at British Columbia's Children's Hospital. Information was collected regarding tumor location, surgical approach, CSF diversion, dural grafting, and use of tissue glue. Multiple univariate analyses and step-wise logistic regression were performed to identify factors associated with pseudomeningocele formation or CSF leak. A pseudomeningocele was said to be present if it was noted in the clinical records or if a fluid collection was present superficial to the craniotomy flap on a postoperative CT or MR scan. RESULTS: Out of 174 posterior fossa operations, 53 pseudomeningoceles with or without CSF leak were identified along with five CSF leaks in the absence of pseudomeningocele (33%). None of the factors examined reached statistical significance, although there was a trend towards higher rates in patients with external CSF drainage (P=0.06631), dural graft usage (p=0.06492), and patients in whom tissue glue was used (p=0.06181). On logistic regression, only tissue glue use and external CSF drainage were associated with increased incidence of pseudomeningocele and/or CSF leak. CONCLUSION: In this retrospective study, the use of tissue glue, dural grafts, and external ventricular drainage was not associated with a reduced rate of clinically or radiologically diagnosed pseudomeningocele formation or postoperative CSF leak. The results of this study provide a basis for planning a randomized controlled trial to determine the effectiveness of tissue glue and/or dural grafting in preventing these complications.

Cerebrospinal Fluid Otorrhea↗
PubMed2006

A simplified approach to analysing bio-electrical impedance data in epidemiological surveys.

BACKGROUND: Bio-electrical impedance analysis (BIA) is widely used to estimate body composition. It is simple, quick and cheap, but less accurate than other methods. It has potential epidemiological value, but has conventionally required validation before application. AIMS: To develop a simple method of expressing weight, height and impedance data that avoids the need for population-specific validation equations in order to facilitate epidemiological application. METHODS: Body composition was measured using the four-component model in young adults (43 males, 90 females). Impedance (R) was measured hand-foot and foot-foot. Lean mass and fat mass were adjusted for height to give lean mass index (LMI) and fat mass index (FMI). Based on theoretical principles, we generated the index 1/R, which provides an index of body water adjusted for height. Sex-specific regression models were used to investigate the relationships between (a) 1/R and LMI, and (b) body mass index (BMI) adjusted for 1/R and FMI. The success of this approach was evaluated in relation to the conventional BIA approach, using correlation analysis. RESULTS: 1/R was a highly significant predictor of LMI. BMI adjusted for 1/R was a significant predictor of FMI. Our approach performed as well as the conventional approach for LMI, but not for FMI. DISCUSSION: Direct use of BIA data, rather than their combination with population-specific equations for the prediction of total body water, proved successful at ranking individuals of both sexes in terms of LMI and FMI. The index 1/R may prove particularly valuable in epidemiological studies where ranking of LMI is required.

Adipose Tissue↗
PubMed2006

Subjective effects of additional doses of buprenorphine in patients on buprenorphine maintenance.

OBJECTIVES: Buprenorphine has considerable abuse potential. Patients who are maintained on buprenorphine (for opioid dependence) further use additional doses besides its maintenance dose. Subjective effects of the additional doses of buprenorphine in patients on buprenorphine maintenance patients is focused in this study. METHODS: Nineteen subjects who were maintained on buprenorphine 4mg, s/l per day for at least 1month were admitted and given three additional doses of buprenorphine 2mg, s/l at the interval of 2h each and subjective effects were assessed with the help of standard tools after 2h of each dose and the next day also. Drug was given in a cumulative dose design in the inpatient unit of a de-addiction centre. RESULTS: Dysphoria and sleepiness increased while euphoria and drug liking decreased with additional doses of buprenorphine. These changes were statistically significant and were highest at maximum cumulative dose of 10mg. CONCLUSION: Results suggest that abuse liability of buprenorphine in these subjects is low in higher doses. However, these findings need to be replicated in this group of patients to make a comment on clinical implication.

Adult↗
PubMed2006

Triplication of colon with diphallus and complete duplication of bladder and urethra.

Gastrointestinal duplications are a common type of congenital anomaly usually restricted to one part of the gut. Triplication of colon is a rare variation of duplication of the hindgut. Hindgut duplications are commonly associated with anomalies of other derivatives of the cloaca, namely, the lower genitourinary system. Here, we describe a child with triplication of colon with associated duplication of bladder and urethra and diphallus. The child described here is the only reported survivor with triplication.

Colon↗
PubMed2006

Occurrence of overlooked zoonotic tuberculosis: detection of Mycobacterium bovis in human cerebrospinal fluid.

The paucibacillary nature of the cerebrospinal fluid (CSF) has been a major obstacle in the diagnosis of human tuberculous meningitis (TBM). This study shows that with molecular techniques direct precise determination to the species level of mycobacterial pathogens can be made. The present report describes the utility of a nested PCR (N-PCR) assay (A. Mishra, A. Singhal, D. S. Chauhan, V. M. Katoch, K. Srivastava, S. S. Thakral, S. S. Bharadwaj, V. Sreenivas, and H. K. Prasad, J. Clin. Microbiol. 43:5670-5678, 2005) in detecting M. tuberculosis and M. bovis in human CSF. In 2.8% (6/212) of the samples, M. tuberculosis was detected, and in 17% (36/212), M. bovis was detected. Mixed infection was observed in 22 samples. Comparative analysis of clinical diagnosis, smear microscopy, and N-PCR in 69 patients (TBM, 25; non-TBM, 44) showed that the sensitivity of N-PCR (61.5%) was greater than that of smear microscopy (38.4%). Determination to the species level is important from the viewpoint of determining the prevalence of these mycobacteria in a community and would influence strategies currently adopted for the prevention of tuberculosis.

Animals↗
PubMed2005

Bovine tuberculosis in India: potential basis for zoonosis.

Our laboratory has designed a specific nested-PCR (N-PCR) assay, based on the hupB gene of Mycobacterium tuberculosis (Rv2986c) and Mycobacterium bovis (Mb3010c) as a method to differentiate these closely related species. The present paper deciphers the utility of this assay for identification of pathogenic Mycobacteria in clinical samples. Extra-pulmonary clinical samples obtained from cattle and humans were investigated. Pre-dominance of M. tuberculosis (15.7%) and M. bovis (26.8%) was seen in humans and cattle, respectively. However, more importantly, both mycobacterial pathogens (mixed infection) were identified in a number of samples. In humans 8.7% of the samples and 35.7% in cattle were classified as mixed infection. The detection of mixed infection with the mycobacterial pathogenic duo in humans and bovines denotes the prospect of potential transmission of these pathogens from humans to cattle (zoonosis) and vice versa (reverse zoonosis).

Animals↗
PubMed2005

Lamb wave characteristics of thickness-graded piezoelectric IDT.

An equivalent single layer model of Lamb wave generation by thickness-graded piezoelectric IDT on host structure is developed. Various additional complexities, such as the coupling between the Lamb wave modes, complicated nature of the electro-mechanical excitation are considered. The model of infinite IDT is extended to deal with the finite IDT with edge discontinuities. The effects of electromechanical coupling and thickness gradation on the wavelength shifts are investigated. The problem of electrically driven instability within the IDT is analyzed. Numerical results are reported by considering Al2O3/PZT IDT as integral part of the host structure, which show that there are significant changes and improvements in the Lamb wave characteristics due to the graded configuration. Most important among these is the reduced dispersiveness of the Lamb wave modes, which is useful in launching a SAW that propagates with narrower pulse width and less attenuation.

Electrodes↗
PubMed2005

Fetal, infant and childhood growth: relationships with body composition in Brazilian boys aged 9 years.

BACKGROUND: Early growth rate has been linked to later obesity categorised by body mass index (BMI), but the development of body composition has rarely been studied. METHODS: We tested the hypotheses that (1) birthweight and weight gain in (2) infancy or (3) childhood are associated with later body composition, in 172 Brazilian boys followed longitudinally since birth. Growth was assessed using measurements of weight and height at birth, 6 months, and 1 and 4 y. Measurements at 9 y comprised height, weight and body composition using foot-foot impedance. RESULTS: Birthweight was associated with later height and lean mass (LM), but not fatness. Weight gain 0-6 months was associated with later height and LM, and with obesity prevalence according to BMI, but not with fatness. Weight gain 1-4 y was associated with later fatness and LM. Weight gain 4-9 y was strongly associated with fatness but not LM. Early growth rate did not correlate positively with subsequent growth rate. CONCLUSIONS: Early rapid weight gain increased the risk of later obesity, but not through a direct effect on fatness. Childhood weight gain remained the dominant risk factor for later obesity. The reported link between early growth and later obesity may be due partly to hormonal programming, and partly to the contribution of LM to obesity indices based on weight and height. Whether our findings apply to other populations requires further research.

Birth Weight↗
PubMed2005

Direct detection and identification of Mycobacterium tuberculosis and Mycobacterium bovis in bovine samples by a novel nested PCR assay: correlation with conventional techniques.

Mycobacterium tuberculosis and M. bovis infect animals and humans. Their epidemiology in developed and developing countries differs, owing to differences in the implementation of preventive measures (World Health Organization, 1999). Identification and differentiation of these closely related mycobacterial species would help to determine the source, reservoirs of infection, and disease burden due to diverse mycobacterial pathogens. The utility of the hupB gene (Rv2986c in M. tuberculosis, or Mb3010c in M. bovis) to differentiate M. tuberculosis and M. bovis was evaluated by a PCR-restriction fragment length polymorphism (RFLP) assay with 56 characterized bovine isolates. The degree of concordance between the PCR-RFLP assay and the microbiological characterization was 99.0% (P < 0.001). A nested PCR (N-PCR) assay was developed, replacing the PCR-RFLP assay for direct detection of M. tuberculosis and M. bovis in bovine samples. The N-PCR products of M. tuberculosis and M. bovis corresponded to 116 and 89 bp, respectively. The detection limit of mycobacterial DNA by N-PCR was 50 fg, equivalent to five tubercle bacilli. M. tuberculosis and/or M. bovis was detected in 55.5% (105/189) of the samples by N-PCR, compared to 9.4% (18/189) by culture. The sensitivities of N-PCR and culture were 97.3 and 29.7, respectively, and their specificities were 22.2 and 77.7%, respectively. The percentages of animals or samples identified as infected with M. tuberculosis or M. bovis by N-PCR and culture reflected the clinical categorizations of the cattle (P of <0.05 to <0.01). Mixed infection by N-PCR was detected in 22 animals, whereas by culture mixed infection was detected in 1 animal.

Animals↗
PubMed2004

The safety and efficacy of leflunomide in combination with infliximab in rheumatoid arthritis.

OBJECTIVE: To report the safety and efficacy of leflunomide (LEF) in combination with infliximab (INF) for the treatment of rheumatoid arthritis. METHODS: In an open, multicenter, retrospective study, data were collected on the safety and efficacy of LEF and INF. RESULTS: Eighty-eight patients received the combination of LEF and INF for an average of 6.6 months and a total exposure of 581 patient-months. The mean duration of LEF was 17 +/- 9 months (range 3-32 months; median 18.5 months) with an average of 4.8 INF infusions per patient. In all but 3 subjects, LEF was used initially and INF was added later. Infusion reactions occurred in 3 patients (0.7% of all infusions). A total of 34% of subjects experienced adverse events and in 6 (6.8% of the group) these were deemed serious. Ten infections occurred when patients were taking the combination; 9 patients recovered fully and 1 died of bacterial pneumonia. A lifetime smoker developed lung cancer and another patient was found to have colon cancer. CONCLUSIONS: The adverse events noted within the combination therapy group were in keeping with the known risks of each drug when used individually. Limited data were available on efficacy, but a general improvement in disease control was noted with the combination of drugs, which for most patients involved the addition of INF to previous use of LEF.

Adult↗
PubMed2004

Trauma recidivism in a large urban canadian population.

BACKGROUND: Prevention of trauma might be achieved by risk factor modification. Identification of such risk factors can be pursued by various means. Trauma recidivists may possess and highlight risk factors. Accordingly, trauma recidivists were analyzed as a method to elucidate trauma risk factors. METHODS: A retrospective analysis of 13,057 trauma patients in Toronto was conducted. Forty-two recidivists were identified, and their first admission was compared with a control group of 84 non-recidivists. RESULTS: The rate of trauma recidivism was 0.38% overall. Trauma recidivists were more likely to be from the inner city, male, homeless, suffering from chronic medical conditions. In addition, psychiatric conditions, an alcoholism history or any alcohol at the time of injury, intentionally injured, or engaged in criminal activity were also significantly more common in recidivists (p <0.05). CONCLUSION: Risk factors for major trauma can be identified by analyzing recidivists in a large urban Canadian population.

Accident Proneness↗
PubMed2004

Use of the hupB gene encoding a histone-like protein of Mycobacterium tuberculosis as a target for detection and differentiation of M. tuberculosis and M. bovis.

The gene for histone-like protein (hupB [Rv2986c]) of Mycobacterium tuberculosis has been identified as a singular target which allows differentiation of two closely related mycobacterial species, namely, M. tuberculosis and M. bovis of the MTB complex, by a PCR assay. The N and S primer-generated PCR amplicons differed in M. tuberculosis and M. bovis; these amplicons were determined to be 645 and 618 bp, respectively. This difference was localized to the C-terminal part of the gene by using primers M and S. The C-terminal PCR amplicons of M. tuberculosis and M. bovis were determined to be 318 and 291 bp, respectively. The differences in the C-terminal portion of the gene were confirmed by restriction fragment length polymorphism analysis and sequencing. Sequence analysis indicated that in M. bovis there was a deletion of 27 bp (9 amino acids) in frame after codon 128 in the C-terminal part of the hupB gene. In the present study 104 mycobacterial strains and 11 nonmycobacterial species were analyzed for hupB gene sequences. Of the 104 mycobacterial strains included, 62 belonged to the MTB complex and 42 were non-MTB complex strains and species. Neither the hupB gene-specific primers (N and S) nor the C-terminal primers (M and S) amplify DNA from any other mycobacteria, making the assay suitable for distinguishing members of the MTB complex from other mycobacterial species, as well as for differentiating between members of the MTB complex, namely, M. tuberculosis and M. bovis.

Base Sequence↗
PubMed2002

Body composition in early onset eating disorders.

BACKGROUND: Body mass index (BMI) or equivalent weight for height indices are the most widely used measures of body composition in early onset and adolescent eating disorders. Although of value as screening instruments the limitation in disease states is their inability to discriminate fat and fat-free components of body weight. OBJECTIVE: To compare height-adjusted fat and fat-free components of body composition in children and young adolescents with different types of eating disorders with those of age matched reference children. DESIGN: Weight, height, triceps and subscapular skinfold thickness were measured in 172 children (aged 7-16 y) with eating disorders receiving specialist treatment. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated using Slaughter's and Deurenberg's equations and normalisation for height. Using data from 157 normal children, representative of the UK 1990 growth reference data, reference curves for FMI and FFMI+/-2 s.d. were derived. Results for patient groups were superimposed on these reference curves. RESULTS: FMI and FFMI were both reduced in eating disorders associated with malnutrition, including anorexia nervosa (AN). AN subjects did not differ from other subjects with comparable degrees of malnutrition. Children with eating disorders of normal weight, such as bulimia nervosa and selective eating, did not differ significantly from reference children in their relative FM and FFM. CONCLUSIONS: FM and FFM merit independent consideration in disorders of malnutrition in children, rather than expressing data as percentage body fat or percentage BMI. The implications of loss of FFM on growth and development merit further investigation.

Adipose Tissue↗
PubMed2002

Association between cerebrospinal fluid interleukin-6 concentrations and outcome after severe human traumatic brain injury.

Acute inflammation plays a significant role in the pathophysiology of traumatic brain injury (TBI). However, the specific relationships between inflammatory mediators and patient outcome following TBI have not been fully established. In this study, we measured plasma and cerebrospinal fluid interleukin-1 (IL-1) and interleukin-6 (IL-6) concentrations in 36 patients, following severe TBI. Patients were monitored with continuous measurements of somatosensory-evoked potentials (SSEP) to derive an established surrogate outcome measurement, the 96-h evoked potential (SSEP96). Clinical outcomes were assessed at 3 months using the Glasgow Outcome Scale (GOS). Peak cerebrospinal fluid (CSF) IL-1 and IL-6 concentrations were significantly higher than those observed in the plasma [median 6.5 pg/mL (range 1.4-25.0) vs. 3.0 (0.8-7.6) for IL-1, and 650 (130-7,214) vs. 253 (52-1,506) for IL-6, p < 0.001 for both]. Peak CSF IL-6 levels correlated with SSEP96 (r = 0.42; p = 0.0133), and peak CSF IL-6 levels were higher with improved GOS (p = 0.024). Multiple regression analysis identified that age (p = 0.0072), pupillary abnormality (p = 0.021), the presence of mass lesion (p = 0.023), and peak CSF IL-6 concentrations (p = 0.026) were all statistically significant predictors of clinical outcome following TBI. These results suggest that peak CSF IL-6 concentrations correlate with improved outcome following TBI. This finding helps to characterize the inflammatory reaction associated with TBI and may help to develop improved treatment strategies for patients with TBI.

Adolescent↗
PubMed2001

Preterm birth, vascular function, and risk factors for atherosclerosis.

Low birthweight may predispose to the development of atherosclerosis later in life. We have tested the hypothesis that low birthweight as a result of preterm birth is associated with reduced flow-mediated endothelial-dependent vasodilation (FMD), which is an early stage in the development of atherosclerosis. Mean FMD in adolescents born preterm who had a low birthweight did not differ from that for controls born at term (0.225 mm vs 0.220 mm, SD 0.1 for both means, p=0.78). Our findings indicate that low birthweight attributable to prematurity does not increase the risk of vascular disease later in life.

Adolescent↗
PubMed2001

Early nutrition in preterm infants and later blood pressure: two cohorts after randomised trials.

BACKGROUND: Despite data relating body size in early life to later cardiovascular outcomes, the hypothesis that nutrition affects such outcomes has not been established. Breastfeeding has been associated with lower blood pressure in later life, but previous studies have not controlled for possible confounding factors by using a randomised design with prospective follow-up. We undertook such a study to test the hypothesis that early diet programmes blood pressure in later life in children randomly assigned different diets at birth. METHODS: Blood pressure was measured at age 13-16 years in 216 (23%) of a cohort of 926 children who were born prematurely and had participated at birth in two parallel randomised trials in five neonatal units in the UK. Dietary interventions were: donated banked breastmilk versus preterm formula and standard term formula versus preterm formula. FINDINGS: Children followed up at age 13-16 years were similar to those not followed up in terms of social class and anthropometry at birth. Mean arterial blood pressure at age 13-16 years was lower in the 66 children assigned banked breastmilk (alone or in addition to mother's milk) than in the 64 assigned preterm formula (mean 81.9 [SD 7.8] vs 86.1 [6.5] mm Hg; 95% CI for difference -6.6 to -1.6; p=0.001). In non-randomised analyses, the proportion of enteral intake as human milk in the neonatal period was inversely related to later mean arterial pressure (beta=-0.3 mm Hg per 10% increase [95% CI -0.5 to -0.1]; p=0.006). No differences were found in the term formula (n=44) versus preterm formula (n=42) comparison. INTERPRETATION: Breastmilk consumption was associated with lower later blood pressure in children born prematurely. Our data provide experimental evidence of programming of a cardiovascular risk factor by early diet and further support the long-term beneficial effects of breastmilk.

Adolescent↗