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Biomedical subjects

S Gambhir

Publications and source records attributed to S Gambhir.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of a new effect-site controlled, patient-maintained sedation system in dental patients.

We have designed a new effect-site controlled, patient-maintained sedation system for delivering propofol. In the previous systems we developed, the patients retained the use of the handset throughout the procedure and were able to increase the level of sedation. However, it was found that this could potentially lead to oversedation. In the present system, the patients were able to increase their level of sedation until a level was reached that was judged by the patients as being adequate to allow them to tolerate the injection of dental local anaesthetic. The handset was then taken from the patients and the effect site concentration of propofol was maintained at that level for the remainder of the procedure. To assess its safety and efficacy, the system was used to sedate 40 patients presenting for dental procedures under sedation. The system was used successfully and treatment was completed in 39 patients. The system was found to be safe. Both surgeon and patient approval scores were high. Although this study demonstrates the efficacy of effect-site controlled, patient-maintained propofol sedation in this group of patients, further work is required to confirm its safety.

Adult↗
PubMed2005

Do healthy potential kidney donors in india have an average glomerular filtration rate of 81.4 ml/min?

BACKGROUND: Until now, a normal reference range for glomerular filtration rate (GFR) in adult Indian potential kidney donors has not been determined and values from a western population are being used as reference. AIM: To determine the reference range of GFR in healthy adult Indian potential kidney donors. BASIC PROCEDURES: GFR was measured in 610 (250 male, 360 female, average age 35.16 years) healthy potential kidney donors using the 99mTc-DTPA (diethylenetriamine pentaacetic acid) two-plasma sample method of Russell. RESULTS: The mean body surface area (BSA)-normalized GFR value of a young healthy Indian adult potential kidney donor was calculated as 81.4 +/- 19.4 ml/min/1.73 m2 BSA--for males it was 82.3 +/- 21.3 ml/min/1.73 m2 BSA and for females 80.8 +/- 18.1 ml/min/1.73 m2 BSA. There was no significant difference between derived mean GFR values in males and females with a p value of 0.37. CONCLUSIONS: The normal GFR value for the healthy Indian adult potential kidney donor appears to be much lower than the accepted value for a western population. The mean GFR value of a young healthy Indian adult potential kidney donor is 81.4 +/- 19.4 ml/min/1.73 m2 BSA, which is significantly different from the normal value of 109-125 ml/min derived from a western population. These findings might be useful in deciding on a suitable kidney donor in an Indian context.

Adult↗
PubMed2005

Use of atropine in patients with recent myocardial infarction during exercise myocardial perfusion study. Use of atropine during exercise myocardial perfusion SPECT.

BACKGROUND: Patients with recent myocardial infarction frequently require a myocardial perfusion study for risk stratification. However a conclusive study cannot be accomplished in many due to non-attainment of target heart rate. AIM OF THE STUDY: To evaluate the effect of pre-stress administration of atropine in exercise performance of patients with recent myocardial infarction. MATERIAL AND METHODS: Study included 43 test and 43 control patients and were matched for their age, sex, status of pretest exercise tolerance, area of infarction and for interval between infarction and stress thallium test. Atropine (0.01 mg/kg) was administered intravenously 3 min prior to treadmill stress in all the 43 test patients and no atropine was administered to control patients. RESULTS: Target heart rate was attained in 95.3% patients receiving atropine compared to in 67.4% of control patients. There was no significant difference between mean ages (p>0.33), basal BP (p>0.47), peak BP (p>0.18) of both groups. There was significant difference between the increment in exercise-induced heart rate (p<0.004), peak heart rate (p<0.001) and double product (p<0.001) attained between both groups. No significant adverse effect was noted in patients who received atropine. CONCLUSION: Pre-stress administration of atropine in patients with recent myocardial infarction is safe and results in a significantly better exercise performance, which might be useful in decreasing the number of equivocal myocardial perfusion studies.

Adult↗
PubMed2004

Postoperative residual tumour imaged by contrast-enhanced computed tomography and 201Tl single photon emission tomography: can they predict progression-free survival in high-grade gliomas?

AIMS: To evaluate if postoperative residual tumour imaged by either computed tomography or 201Tl single photon emission tomography (SPECT) carried out postoperatively could predict progression-free survival (PFS) in high-grade malignant gliomas. MATERIALS AND METHODS: Thirty-three patients with high-grade malignant gliomas underwent both contrast-enhanced CT scan and 201Tl-SPECT postoperatively before receiving radiotherapy. The PFS was evaluated against the individual reports of the above two imaging studies by univariate analysis. RESULTS: CT and 201Tl-SPECT were carried out within a median interval of 17 days after surgery. Of the 33 patients, CT and 201Tl-SPECT were reported as positive for residual tumours in 23 (69.7%) and 30 (91%) patients, respectively. Sensitivity, specificity and overall accuracy were 71.4%, 40% and 66.6% for CT, and 96.4%, 40% and 87.8% for 201Tl-SPECT, respectively, and were based on their last follow-up status (P = 0.627 for CT; P = 0.053 for 201Tl-SPECT). The median PFS for patients reported to be positive or negative on CT scan was 4 and 5 months, respectively (P = 0.202). With 201Tl-SPECT, although the median PFS for patients with a positive 201Tl uptake was also 4 months, it had not even reached for those reported having a negative 201Tl uptake (cumulative survival 66.7% at last follow-up) (P = 0.198). However, Karnofsky performance status (KPS) was the only significant predictor on univariate analysis (KPS: < 80 vs. > or = 80; P < 0.001) for PFS. CONCLUSIONS: Although both the imaging modalities have a poor specificity, postoperative 201Tl-SPECT had a significantly better accuracy to predict the status at last follow-up than contrast-enhanced CT. Nevertheless, KPS remained the most significant outcome predictor for PFS in high-grade malignant gliomas.

Adult↗
PubMed2004

A partially blinded randomised controlled trial of patient-maintained propofol sedation and operator controlled midazolam sedation in third molar extractions.

Patient-maintained sedation using propofol has recently been shown to be effective for dental surgery. We compared this new technique to the established technique of operator administered midazolam. The two groups were compared before, during and after sedation. The two primary outcomes were time until discharge and oxygen saturation. Vital signs, anxiety and psychomotor skills were also compared. State anxiety was reduced to a greater extent in the propofol group (mean difference 10 (SD 4) mm; p = 0.010. Propofol patients recovered quicker (mean difference 7 (SD 1.4) min; p = 0.001). Propofol patients had a smaller reduction in arterial oxygen saturation (mean difference 0.8 (SD 0.3)%; p = 0.030), and a reduced increase in heart rate (mean difference 9 (SD 2) beats.min(-1); p < 0.001). Both techniques were well tolerated and safe. Propofol sedation offered superior anxiolysis, quicker recovery, less amnesia and less depression of simple psychomotor function.

Adolescent↗
PubMed2002

Clinical profile of hereditary spherocytosis in North India.

AIMS OF THE STUDY: Hereditary spherocytosis (HS) is a familial hemolytic disorder manifesting as anaemia, recurrent jaundice, splenomegaly with marked heterogeneity in clinical presentation. The objective was to study the clinical spectrum of the disorder in India. METHODOLOGY: We studied 50 HS patients and followed them for up to six years (Age range 2-47 years). RESULTS: The presenting features were jaundice 35 out of 50, anaemia 30 out of 50 (requiring blood transfusion in 25). Splenomegaly was found in all patients. Increased osmotic fragility was found in all patients whereas spherocytes were found in only 19 out of 42 patients. Reduced red cell survival was noted in 9/12 patients studied with 51Cr labeled RBCs. There was a definite improvement in the hemoglobin values in those who underwent splenectomy. Thirteen cases had similarly affected family member/s. Fifteen of the cases had family history consistent with autosomal dominant (AD) inheritance (eight families) while in six cases (5 families), inheritance was likely to be autosomal recessive (AR). There was intrafamilial variability in the age of presentation in the AD families. CONCLUSIONS: Our results suggest that both autosomal dominant and recessive patterns of HS are seen in India and the clinical profile of the Indian HS patients is similar to that described in other populations. HS presenting in childhood is also not uncommon. However, the predominant underlying protein defect in Indian patients needs to be characterized.

Adolescent↗
PubMed2000

Classifying choledochal cysts using hepatobiliary scintigraphy.

PURPOSE: This retrospective study was designed to classify choledochal cysts on the basis of the findings of hepatobiliary scintigraphy. METHODS: Twenty-one patients with choledochal cysts (15 female, 6 male; mean age, 20 years) proved on the findings of endoscopic retrograde cholangiopancreatography (ERCP) or surgery and histopathologic analysis were included in the study. Two nuclear medicine physicians, blinded with regard to cholangiographic and operative details, were asked to review and to classify the type of choledochal cyst seen on the hepatobiliary scan. Later, scintigraphic results were compared with ERCP and surgical findings for a reference standard. RESULTS: The findings of hepatobiliary scintigraphy correlated with ERCP and surgical findings in 18 of 21 cases (86%). Scintiscans correctly identified all type 1 cysts (12/12). The sensitivity of scintigraphy in diagnosing type 4 cysts was 66% (6 of 9 cases). It underestimated the intrahepatic extent of disease in type 4a biliary cysts (37%). CONCLUSION: This study illustrates the utility of hepatobiliary scintigraphy in diagnosing type 1 and 4 choledochal cysts.

Adult↗
PubMed2000

Aspirin renography in the diagnosis of renovascular hypertension: a comparative study with captopril renography.

Captopril renography is used for the non-invasive diagnosis of renovascular hypertension, but suffers from the drawbacks of lower sensitivity and false-positive tests due to a fall in blood pressure. Aspirin renography has been proposed as a useful test for evaluation of unilateral renal artery stenoses of moderate degree. We studied the clinical usefulness of aspirin renography in 12 patients with a clinical suspicion of renovascular hypertension and compared it with captopril renography using 99Tcm-DTPA. The test was considered positive if there were changes in the time-activity curve according to the criteria specified by the American Society of Hypertension Working Group. Four patients with discordant results between captopril and aspirin underwent intra-arterial digital subtraction angiography. In two patients, the renal arteries were normal; captopril was false-positive in both these patients. Bilateral stenosis was noted in the third patient, with captopril being false-negative on the right side with moderate stenosis, whereas aspirin was true-positive. There was unilateral stenosis in the fourth patient; captopril was false-positive on the contralateral side. Our results suggest that aspirin renography is superior to captopril renography in the assessment of patients with a suspicion of both unilateral and bilateral renovascular hypertension.

Adolescent↗
PubMed1999

Power Doppler imaging of acute renal transplant rejection.

PURPOSE: We evaluated the usefulness of power Doppler imaging (PDI) in diagnosing acute renal-transplant rejection. METHODS: Twenty-eight patients underwent 33 renal-transplant biopsies for suspected acute rejection. Patterns of renal parenchymal vascularity revealed by PDI in patients with abnormal biopsy results were compared with patterns in a group who had normal biopsy results. PDI examinations were reviewed retrospectively by 2 independent radiologists who had no knowledge of the biopsy results. A PDI diagnosis of acute rejection required marked vascular pruning in both the cortex and medulla. PDI results then were compared with transplant-biopsy results. RESULTS: The sensitivity and specificity of PDI for diagnosing acute renal-transplant rejection were 40% and 100%, respectively. None of the patients with negative biopsy results had PDI abnormalities. The negative predictive value of PDI was 33%, and the positive predictive value was 100%. CONCLUSIONS: In our study, an abnormal sonogram was highly predictive of acute transplant rejection. However, a normal sonogram did not exclude the possibility of rejection.

Acute Disease↗
PubMed1997

Assessment of vasoreactivity in brain edema by acetazolamide activation SPECT and PET.

Our study was performed to find out cerebrovascular reactivity post acetazolamide administration in patients with peritumoral edema. Adult patients (n = 9) underwent CBF measurement by 99mTc-HMPAO SPECT pre and post 1 gram i.v. acetazolamide. In all patients, this procedure was repeated once again within 10 days of performing tumor removal. Five of these patients also underwent CBF measurement pre and post 1 gram i.v. acetazolamide post surgery only using oxygen-15 labeled H2O PET. Asymmetry index (AI) was calculated as ratio of ROI counts in the peritumoral edematous area and symmetrical ROI on the contralateral normal hemisphere. The AI increased after acetazolamide in edematous gray matter post operatively though the resting AI remained almost same post operatively. AI in edematous white matter showed non-significant increase post operatively both at rest and after acetazolamide. Good linear correlation of AI between PET and SPECT was observed both in gray and white matter. The improvement of vascular reactivity in edematous gray matter after tumor removal suggests that mass effect not only reduces CBF but also suppresses vascular reactivity. White matter vascular reactivity in early post operative period is little improved, possibly due to factors other than mass effect i.e. excess water accumulation in white matter perivascular space.

Acetazolamide↗
PubMed1997

Comparison of vasodilatory effect of carbon dioxide inhalation and intravenous acetazolamide on brain vasculature using positron emission tomography.

Carbon dioxide (CO2) and acetazolamide are increasingly being used as vasodilators to detect cerebrovascular reserve capacity in patients of chronic cerebrovascular disease. The functional cerebrovascular reserve or ability of cerebral vessels to lower their resistance in response to decrease in cerebral perfusion pressure is expressed as change in cerebral blood flow from baseline under a vasodilatory stimuli. Theoretically a vasodilator causing maximum vasodilation, and thereby expressing complete reserve capacity would be more suitable for such a purpose. We quantitatively compared the vasodilating effect of 5% CO2 inhalation and 1 g of intravenous acetazolamide by positron emission tomography. Cerebrovascular reserve was quantified in six patients with chronic cerebrovascular disease in the same sitting, using oxygen-15 labeled water (H2(15)O) positron emission tomography at rest, during 5% CO2 inhalation and after 1 g intravenous acetazolamide. A significant linear correlation in both nonlesion hemisphere (r = 0.701, p < 0.001) and in lesion hemisphere (r = 0.626, p < 0.005) was found between CO2 and acetazolamide for cerebrovascular reserve capacity. This correlation improved by considering cerebrovascular reserve per unit change in arterial carbon dioxide (r = 0.744, p < 0.001 in nonlesion hemisphere and r = 0.721, p < 0.001 in lesion hemisphere). The quantitative value of global reserve capacity was different by CO2 stimuli (5.2%) and acetazolamide (49.7%). Though a similar vasodilatory response is elicited by both vasodilators, acetazolamide seems to be more potent and therefore should be preferred to detect patients with exhausted cerebrovascular reserve capacity.

Acetazolamide↗
PubMed1996

Fluorine-18 fluoro-2-deoxyglucose positron emission tomography in recurrent rectal cancer: relation to tumour size and cellularity.

The aim of this study was to assess the value of fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography in patients with recurrent rectal cancer, in relation to tumour size and cellularity. Thirty-seven patients (21 mean and 16 women; mean age, 55.4+/-9.58 years) with suspected recurrence of rectal cancer were studied. FDG uptake was quantified by the differential absorption ratio (DAR). In 29 patients magnetic resonance imaging was also performed. To evaluate the signal intensity of the lesion, the lesion to muscle signal intensity ratios (SIR) were calculated on T2-weighted images. In seven patients who received surgical treatment the DAR and SIR were compared with the tumour cellularity. All 32 patients with confirmed recurrence showed increased FDG accumulation in the mass (DAR=4.57+/-1.89) in comparison with low FDG accumulation in five patients with scar (DAR=1.17+/-0.43). There was a significant correlation (r=0.661, P<0.001) between the DAR and the tumour diameter. There was no correlation between the DAR and SIR, whereas there was a significant correlation (r=0.565, P<0.01) between the DAR corrected using count recovery coefficient (DAR*) and SIR. In the histopathological findings there was a tendency for the DAR* and SIR to correlate with tumour cellularity. It is concluded that the DAR of recurrent rectal cancer should be evaluated taking into consideration the tumour size and cellularity.

Deoxyglucose↗
PubMed1994

99mTc-insulin: labeling, biodistribution and scintiimaging in animals.

Porcine insulin was labeled with 99mTc by direct tin reduction. More than 95% labeling efficiency was obtained on paper chromatography in saline and methyl ethyl ketone. The stability of the labeled compound was confirmed by paper chromatography at 3 h post-labeling and by human serum albumin (HSA) challenge. PAGE pattern indicated no change in the electrophoretic behavior and the molecular size of insulin after the labeling procedure. Biodistribution in rats shows that kidney took up the maximum amount of 99mTc-insulin; maxima being maintained throughout 24 h post-injection. Liver and intestine were the other organs with significant uptake; the rest localizing little or negligible radioactivity. Most of the radioactivity was excreted via the renal pathway into urine. Scintiimages conformed to the biodistribution data. The results of this study present the potential of 99mTc-labeling of insulin by a simple method.

Animals↗
PubMed1994

Clinical evaluation of Tc-99m cystine. A new renal radiopharmaceutical.

Tc-99m cystine has been proved to be a good renal agent in animals. Its clinical evaluation has not been reported. In this study, Tc-99m cystine is used for evaluation of renal function in normal subjects and patients with chronic renal failure as well as in renal transplant patients. The results are compared with similar studies using Tc-99m DTPA and Tc-99m GHA. The clearance values also are compared with I-131 OIH. The results show that Tc-99m cystine has good radiopharmaceutical characteristics suitable for evaluation of both renal function as well as morphology.

Cystine↗
PubMed1994

Clinical evaluation of Tc-99m cystine. A new renal radiopharmaceutical.

Tc-99m cystine has been proven to be a good renal agent in animals, but its clinical evaluation has not been reported. In this study, Tc-99m cystine was used for evaluation of renal function in normal subjects and patients with chronic renal failure as well as in renal transplant patients. The results are compared with similar studies that used Tc-99m DTPA and Tc-99m GHA. The clearance values also have been compared with I-131 OIH clearance. The results show that Tc-99m cystine has good radiopharmaceutical characteristics suitable for evaluation of both renal function as well as morphology.

Cystine↗
PubMed1994

Interventional radiology in the management of superior thyroid artery injury which presents as a diagnostic dilemma.

Following a forgotten iron splinter injury, a 19 year old male developed a slowly increasing extrathyroidal haematoma, which presented as a diagnostic dilemma. Surgical exploration failed to establish a diagnosis and was complicated by severe haemorrhage. Emergency angiography demonstrated injury to the superior thyroid artery. Therapeutic embolization and surgical exploration resulted in functional and anatomical recovery of the thyroid lobe.

Adult↗
PubMed1993

Skeletal scintigraphic findings in endemic skeletal fluorosis.

Endemic skeletal fluorosis is characterized by bone, joint and muscle pain, progressive ankylosis of various joints and crippling deformities. Whole body skeletal scintigraphy with 99Tcm-methylene diphosphonate was performed for 17 symptomatic subjects suffering from this disorder. The fluoride content of drinking water ranged from 4.1 to 12.9 mg l-1 (normal < 1 mg l-1). Urinary and serum fluoride levels were markedly elevated. Serum calcium (total and ionized), inorganic phosphorus, creatinine and albumin were essentially normal while serum alkaline phosphatase was elevated in six subjects (mean +/- S.D. 206 +/- 106; range 22-1072 IU l-1). Skeletal radiology revealed a wide spectrum of bony abnormalities. Skeletal scintigraphy revealed a picture similar to metabolic 'superscan' in all subjects, i.e. increased tracer uptake in axial and appendicular skeleton, reduced soft tissue uptake, poor or absent renal images, prominent costochondral junction and 'tie' sign in sternum. Increased uptake was present in all subjects irrespective of age, water fluoride content, serum alkaline phosphatase level and radiological abnormalities. Our findings suggest the presence of a high bone turnover state in endemic skeletal fluorosis irrespective of other variables.

Adolescent↗