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Biomedical subjects

N C Gupta

Publications and source records attributed to N C Gupta.

At least 37 records · Page 2Linked to original sources
PubMed1996

Repellency of Lantana camara (Verbenaceae) flowers against Aedes mosquitoes.

The repellent effect of Lantana camara flowers was evaluated against Aedes mosquitoes. Lantana flower extract in coconut oil provided 94.5% protection from Aedes albopictus and Ae. aegypti. The mean protection time was 1.9 h. One application of Lantana flower can provide more than 50% protection up to 4 h against the possible bites of Aedes mosquitoes. No adverse effects of the human volunteers were observed through 3 months after the application.

Aedes↗
PubMed1995

PET-FDG imaging and transthoracic needle lung aspiration biopsy in evaluation of pulmonary lesions. A comparative risk-benefit analysis.

BACKGROUND AND OBJECTIVE: Positron emission tomography (PET) utilizing 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) has been demonstrated to be highly accurate in differentiating benign from malignant pulmonary nodules. Transthoracic fine-needle aspiration biopsy (TTNA) is generally the initial procedure of choice in the evaluation of peripheral lesions suspected to be malignant. Our objective was to determine whether PET-FDG imaging, a noninvasive test, was equally efficacious as TTNA in the evaluation of lung lesions suspected to be malignant. PATIENT SELECTION: Thirty-three patients with 35 lung lesions who had undergone both PET-FDG imaging and TTNA were retrospectively selected from an ongoing prospective study of PET-FDG imaging in the evaluation of solitary pulmonary nodules. MEASUREMENTS: Diagnostic efficacy was determined by calculating sensitivity, specificity, positive and negative predictive value, and overall predictive accuracy for both PET-FDG imaging and TTNA in differentiating benign from malignant lesions. Complication rate also was documented for the two tests. RESULTS: The PET imaging correctly identified all 26 malignant lesions, including 21 lesions diagnosed by TTNA and 7 of the 9 benign lung lesions. The TTNA was positive for malignancy in 21 lung lesions and missed the diagnosis of malignancy in 5 lesions. Diagnostic sensitivity, specificity, positive and negative predictive value, and overall predictive accuracy was 100, 78, 93, 100, and 94% for PET imaging and 81, 100, 100, 64, and 86 for TTNA, respectively. Pneumothorax was documented in 16 patients (46%), and 9 patients (26%) required a chest tube. There were no complications with PET imaging. CONCLUSION: We conclude that PET imaging of the lung is as efficacious as TTNA, with less risk, and offers an alternate noninvasive option in the evaluation and management of lung lesions suspected to be malignant.

Adult↗
PubMed1994

Experience with positron emission tomography (PET) scans in patients with ovarian cancer.

Our first year of experience in the use of PET scanning in the management of nine patients with ovarian cancer leads us to conclude that this promising new technique may be more sensitive than either serum CA-125 determinations or computed tomography for the detection and demonstration of residual or recurrent abdominal and pelvic tumor. Seven of these patients underwent second-look laparotomy which confirmed our impressions from preoperative PET scans in six patients, and the one other scan showed a focus of metabolic uptake coinciding with residual tumor in our retrospective review. The clinical courses of two other patients who did not undergo laparotomy confirmed the impressions gained from PET scans.

Adult↗
PubMed1994

Positron emission tomography for preoperative staging of colorectal carcinoma.

PURPOSE: Positron emission tomography (PET) is an imaging technique based on in vivo cellular metabolism. Increased glucose metabolism in neoplastic cells is detected by using fluorine-18 deoxyglucose. In an ongoing pilot study to determine the usefulness of this technique, PET is compared with computerized tomography (CT) for the preoperative staging of colorectal carcinoma. METHODS: Sixteen patients were evaluated with both PET and CT of the abdomen and pelvis. Results were compared with operative and histopathologic findings. Fifteen malignant lesions were found in 16 patients by histology. PET had a positive predictive value of 93 percent and a negative predictive value of 50 percent. By comparison CT had a positive predictive value of 100 percent and a negative predictive value of 27 percent. CONCLUSIONS: These preliminary results indicate that PET has increased sensitivity for staging colorectal carcinoma, whereas CT has higher specificity. The predictive value of a positive PET compares favorably with CT. Furthermore, the predictive accuracy for detection of colorectal carcinoma is 83 percent for PET and 56 percent for CT.

Adult↗
PubMed1994

Positron emission tomography of lung tumors and mediastinal lymph nodes using [18F]fluorodeoxyglucose. The Members of the PET-Lung Tumor Study Group.

Positron emission tomography detects increased glucose uptake in malignant tissue using the glucose analogue [2-18F]fluoro-2-deoxy-D-glucose. We reviewed the scans obtained in 62 patients with lung tumors. All had undergone computed tomography and had tissue-based diagnoses: 22 had adenocarcinomas, 12 had squamous cell carcinomas, 13 had other malignancies, 1 had organizing pneumonia, 1 had a hamartoma, and 13 had granulomas. Positron emission tomography with [2-18F]fluoro-2-deoxy-D-glucose identified 44 of 47 malignancies. Two of three false-negative findings were tumors that were 1 cm2 or less and the other was a bronchioloalveolar carcinoma. All three false-positive findings were granulomas. The sensitivity and specificity of the technique were 93.6% and 80%, respectively, and the positive and negative predictive values were 93.6% and 80%, respectively. The differential uptake ratio was determined in all 62 patients. The mean differential uptake ratio (+/- the standard error of the mean) for malignant tumors was 6.4 +/- 0.56 and that for benign tumors was 1.14 +/- 0.26 (p < 0.0001, t test). Twenty-five of the patients had N2 lymph nodes evaluated pathologically. Positron emission tomography with [2-18F]fluoro-2-deoxy-D-glucose identified negative N2 nodes in 19 of 22 patients (86%) with negative nodes and positive N2 nodes in 2 of 3 patients (66%) with positive nodes, including one instance missed by computed tomography.(ABSTRACT TRUNCATED AT 250 WORDS)

Deoxyglucose↗
PubMed1994

Standardized uptake values of FDG: body surface area correction is preferable to body weight correction.

UNLABELLED: Standardized uptake values (SUVs) are widely used to measure 18F-fluorodeoxyglucose (FDG) uptake in various tumors. It has been reported that normalization of FDG uptake for patient body weight (SUVbw) overestimates FDG uptake in heavy patients, as their fraction of body fat (with low FDG uptake) is often increased. The objective of this study was to determine if "normalization of FDG uptake for the body surface area" (SUVbsa) is independent of the patient's body size and is more reliable than SUVbw. METHODS: FDG-PET images were acquired on 44 patients (body weight range: 45-115 kg) with cancer. SUVbw [(mCi/g of tissue)/(mCi injected/patient body weight in g)] and SUVbsa [(mCi/g of tissue)/(mCi injected/patient BSA in m2)] were determined for the liver. Since most observers are accustomed to using the SUVbw, the two values were compared by setting the mean SUVbsa equal to that of SUVbw. RESULTS: SUVbw and SUVbsa were 3.42 +/- 0.85 (mean +/- s.d.) and 3.42 +/- 0.60, respectively. The standard deviation of the SUVbsa was smaller than that of SUVbw. More importantly, there was a strong positive correlation between SUVbw and, not only body weight (r = 0.75) but also BSA (r = 0.68), whereas only a weak correlation between SUVbsa and body weight (r = 0.41) or BSA (r = 0.38) was found with a near flat regression line. CONCLUSION: SUVbw overestimates FDG uptake in large patients. SUVbsa appears preferable to SUVbw, since it is minimally affected by the body size.

Body Surface Area↗
PubMed1993

Diagnostic efficacy of PET-FDG imaging in solitary pulmonary nodules. Potential role in evaluation and management.

BACKGROUND: Positron emission tomography (PET), a new noninvasive imaging modality, utilizing 2-[F-18]-fluoro-2-deoxy-D-glucose (FDG), has demonstrated increased FDG uptake in lung tumors. OBJECTIVE: To determine the diagnostic efficacy of PET-FDG imaging in differentiating benign from malignant solitary pulmonary nodules. PATIENT SELECTION: A prospective study of 30 patients who presented with indeterminate solitary pulmonary nodules less than 3 cm in size based on chest radiograph and computed tomographic (CT) scan. SETTING: Two tertiary care medical centers in Omaha, Neb: Creighton University Medical Center and the Omaha Veterans Administration Medical Center. MEASUREMENTS: Positron emission tomographic imaging of the lung was performed 1 h after intravenous injection of 10 mCi of F-18-FDG. Qualitative analysis of the images was performed independently by two observers by visual identification of the areas of increased FDG uptake in the lung nodules. Semiquantitative analysis was performed using computation of differential uptake ratio (DUR). Histologic specimens were obtained in 29 patients (thoracotomy 20, transthoracic needle aspiration biopsy 8, bronchoscopy 1). RESULTS: Positron emission tomographic imaging correctly identified 27 of 30 pulmonary nodules. Diagnostic accuracy was high with sensitivity of 95 percent and specificity of 80 percent. The positive and negative predictive value of PET imaging for solitary pulmonary nodules was 90 percent and 89 percent, respectively. The DUR values were significantly higher for malignant nodules (mean +/- SD, 5.55 +/- 2.79) than benign nodules (mean +/- SD, 0.95 +/- 0.99) (p < 0.001). There was one false-negative result in a patient with a 1-cm nodule identified as a scar adenocarcinoma. There were two false-positive cases and both had caseating granulomas with active inflammation and Histoplasma organisms. CONCLUSION: PET-FDG imaging of the lung, a new noninvasive diagnostic test, has a high degree of accuracy in differentiating benign from malignant pulmonary nodules. PET-FDG imaging could complement CT scanning in the evaluation and treatment of patients with solitary pulmonary nodules.

Aged↗
PubMed1993

Pre-operative staging of colorectal carcinoma using positron emission tomography.

Positron emission tomography (PET) is a unique technique for imaging functional metabolism of normal and diseased tissue. Accelerated rate of glucose metabolism typical of malignant tumor cells can be detected by using fluorine-18 deoxyglucose. In this pilot study, PET FDG imaging was compared to computerized tomography for the pre-operative staging of colorectal carcinoma. We prospectively evaluated 16 patients by simultaneously performing PET FDG and CT imaging for lesions in the liver, colon and rectum. The results were compared to the operative findings in all patients. Twenty tumor sites (lymph nodes 5, colon and rectum 13, liver 2) were found on histology in 16 patients. On comparison with histology, sensitivity, specificity and predictive accuracy for detection of tumor sites were 90%, 66% and 87% with PET as compared to 60%, 100%, and 65% with CT. These findings represent increased sensitivity and predictive accuracy for staging of colorectal carcinoma with PET FDG imaging as compared to CT scanning.

Aged↗
PubMed1992

Comparison of adenosine and exercise thallium-201 single-photon emission computed tomography (SPECT) myocardial perfusion imaging. The GE SPECT Multicenter Adenosine Study Group.

Pharmacologic stress with dipyridamole has provided useful diagnostic, as well as prognostic, information in patients undergoing thallium-201 myocardial perfusion imaging. With its ultrashort half-life and a potent and consistent vasodilator effect, adenosine may be the coronary vasodilator of choice with myocardial perfusion imaging. Fifty-one healthy subjects and 93 patients with suspected coronary artery disease constituted the study group. In this multicenter study the comparative safety and diagnostic efficacy of single-photon emission computed tomography (SPECT) thallium imaging during adenosine-induced coronary hyperemia was compared with exercise treadmill stress. There was a mean increase in heart rate of 37% and a mean decrease in diastolic blood pressure of 5% during the adenosine infusion of 140 micrograms/kg per min for 6 min. Adenosine infusion was well tolerated in 95% of the subjects. Side effects requiring intervention occurred in seven subjects (5%). None of the subjects experienced a life-threatening complication. The sensitivity, specificity and predictive accuracy for detection of coronary artery disease with use of quantitative analysis was 83%, 87% and 84% for adenosine SPECT and 82%, 80% and 81% for exercise SPECT studies, respectively. Most false negative results with adenosine, as well as exercise SPECT studies, occurred in patients with single-vessel disease. The first-order concordance (no defect vs. defect) and second-order concordance (no defect vs. irreversible vs. reversible defect) was 89% and 78% between the two studies, respectively. Thus, the results of adenosine SPECT imaging are highly concordant with exercise SPECT thallium imaging. Adenosine SPECT thallium imaging provides a safe and highly accurate imaging mode for the detection of coronary artery disease.

Adenosine↗
PubMed1992

Considerations in setting up a positron emission tomography center.

Clinically oriented imaging with position emission tomography (PET) has come of age. Given an adequate referral base and physician interest, a compelling argument can be made at all levels of the review process for setting up a PET program in a clinical setting. PET is expensive. It is obvious that the cost of running a PET service depends heavily on an institution's ability to obtain reasonable financing. Educational institutions have the opportunity to acquire special funding through a variety of sources. On the other hand, money can be expensive for private entrepreneurs. It appears that in the near future PET centers will probably remain at educational institutions or large well-financed community hospitals able to raise money at reasonable rates until reimbursement issues are better resolved. Finally, the future of clinical PET may hinge significantly on the ability of commercial radiopharmaceutical suppliers to provide regional fluorodeoxyglucose distribution. As an institutional program development, PET offers opportunities by providing unique clinical data aiding the referral pattern. PET may serve as a magnet for recruitment in many areas and may promote interdisciplinary cooperation. A clinical PET center serves both as a model for future and more widespread use of PET and as a training ground for medical personnel. Finally, the unique capabilities of PET may facilitate grant opportunities.

Facility Design and Construction↗
PubMed1992

Solitary pulmonary nodules: detection of malignancy with PET with 2-[F-18]-fluoro-2-deoxy-D-glucose.

It is estimated that nearly one-third of solitary pulmonary nodules (SPNs) may represent bronchogenic carcinoma. The noninvasive imaging methods used currently (ie, plain radiography, computed tomography) are not reliable for accurate detection of malignancy in most SPNs. The authors prospectively evaluated use of positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) for identification of malignancy in 20 patients with noncalcific, radiographically indeterminate SPNs. PET-FDG imaging demonstrated focal hypermetabolism in 13 biopsy-proved malignant nodules, whereas no increased FDG uptake was seen in the seven benign SPNs. Semiquantitative analysis with computation of differential uptake ratios also helped clearly differentiate benign nodules (mean +/- standard deviation, 0.56 +/- 0.27) from malignant nodules (mean +/- standard deviation, 5.63 +/- 2.38) (P less than .001). Thus, PET-FDG imaging may be a potentially useful noninvasive technique for accurate differentiation of benign and malignant SPNs that are radiographically indeterminate.

Adult↗
PubMed1992

Thallium-201 myocardial imaging in patients with coronary artery disease: comparison of intravenous adenosine and oral dipyridamole.

OBJECTIVE: To compare thallium-201 (201Tl) myocardial perfusion imaging following intravenous adenosine and oral dipyridamole. DESIGN: Open-label, randomized, comparison. SETTING: Outpatient, university-affiliated clinic. PATIENTS: Fifteen patients with angiographically documented coronary artery disease. INTERVENTIONS: Planar 201Tl myocardial perfusion imaging following both intravenous adenosine 140 micrograms/kg/min for six minutes and oral dipyridamole suspension 300 mg. MAIN OUTCOME MEASURES: A comparison between adenosine and dipyridamole was made in the following areas: concordance in interpretation of 201Tl scintigrams, cardiac and noncardiac 201Tl uptake and clearance, hemodynamic and electrocardiographic changes, and adverse effects. RESULTS: The scintigraphic studies showed perfusion defects in 13 patients (87 percent) after dipyridamole and in 15 patients (100 percent) after adenosine. 201Tl uptake and clearance were quantitated in nine myocardial segments and in four extracardiac segments in each patient. 201Tl uptake was not significantly different between adenosine and dipyridamole studies in most cardiac regions. Extracardiac 201Tl uptake was significantly less in the liver and splanchnic regions following adenosine compared with dipyridamole. 201Tl clearance was not significantly different following adenosine and dipyridamole except in the anterolateral region in the anterior view. Hemodynamic changes following administration of intravenous adenosine and oral dipyridamole were not significantly different. Adverse effects were more common with adenosine than with dipyridamole. Adverse effects with adenosine were transient; however, adverse effects with dipyridamole were prolonged and required reversal with aminophylline in 2 patients. No patients required termination of the adenosine infusion or administration of aminophylline. CONCLUSIONS: These preliminary data suggest that adenosine 201Tl imaging may be a useful alternative to dipyridamole 201Tl imaging. Although adenosine produces more frequent adverse effects, they are generally better tolerated than those associated with dipyridamole.

Adenosine↗
PubMed1991

Adenosine in myocardial perfusion imaging using positron emission tomography.

Because of its unique ability to demonstrate the metabolic consequences of myocardial ischemia, positron emission tomography (PET) is extremely valuable in assessing myocardial viability. PET imaging can identify the myocardial segments that are likely to improve after revascularization and may be more sensitive and specific for the detection of coronary artery disease compared with thallium perfusion imaging. Adenosine has several advantages over dipyridamole as a pharmacologic stress agent for use with PET. It produces maximal vasodilation in a significantly greater percentage of patients, is a more potent coronary vasodilator, and its very short half-life may be ideal for use with the very short half-life radioactive tracers used in PET. When combined with metabolic studies, adenosine may be useful for the assessment of patients who received thrombolytic therapy for an acute myocardial infarction.

Adenosine↗
PubMed1991

Computerized identification of pathologic duodenogastric reflux using 24-hour gastric pH monitoring.

Duodenogastric reflux is a naturally occurring sporadic event, the incidence, occurrence, and detrimental effects of which have been difficult to assess. The reliability of 24-hour gastric pH monitoring to detect duodenogastric reflux was studied. Central to the use of pH monitoring for this purpose is confidence in its ability to measure and display pH data in a way that reflects changes in the gastric pH environment with sufficient sensitivity. To test this the gastric pH of 10 dogs was measured in the fasting state, after feeding, and after pentagastrin stimulation. The antrum was more alkaline in the fasting state (p less than 0.01) and the display of data by frequency distribution graph was sensitive enough to reflect induced pH changes. To test the consistency of gastric pH at a given position, simultaneous 24-hour gastric monitoring was performed in 12 normal subjects with two probes placed at either 5 or 10 cm below the lower esophageal sphincter. Only at the 5-cm position did the two probes read within 1 pH unit of each other more than 90% of the time. Based on these principles, gastric pH monitoring was performed 5 cm below the lower esophageal sphincter in 30 normal subjects and 11 patients, fulfilling Ritchie's clinical criteria for pathologic duodenogastric reflux. The data obtained was arranged into 71 variables and subjected to discriminant analysis. Sixteen variables were identified, each with a corresponding coefficient to be used as a multiplier to derive a score. A score of more than +2.2 indicated a high probability of pathologic duodenogastric reflux. The test was applied to a validation population consisting of 10 additional normal subjects and 10 patients meeting Ritchie's criteria. All normal subjects had a normal score and all but one (90%) of the patients had an abnormal score. When compared to O-diisopropyl iminodiacetic acid (DISIDA) scintigraphy in another group of 22 normal subjects and 60 patients, 24-hour gastric pH monitoring was superior in the detection of pathologic duodenogastric reflux. The study shows how the application of computer technology can be used to diagnose pathologic duodenogastric reflux in patients with complex foregut complaints.

Animals↗
PubMed1991

Physiologic assessment of coronary artery fistula.

Coronary artery fistula is an uncommon clinical entity. The most common coronary artery fistula is from the right coronary artery to the right side of the heart, and it is less frequent to the pulmonary artery. The effect of a coronary artery fistula may be physiologically significant because of the steal phenomenon resulting in coronary ischemia. Based on published reports, it is recommended that patients with congenital coronary artery fistulas be considered candidates for elective surgical correction to prevent complications including development of congestive heart failure, angina, subacute bacterial endocarditis, myocardial infarction, and coronary aneurysm formation with rupture or embolization. A patient is presented in whom treadmill-exercise thallium imaging was effective in determining the degree of coronary steal from a coronary artery fistula, leading to successful corrective surgery.

Arterio-Arterial Fistula↗
PubMed1991

Topical indomethacin for vernal keratoconjunctivitis.

Twenty-five patients with vernal keratoconjunctivitis (VKC) were treated with 1% indomethacin eyedrops and were followed for 5 weeks. Apart from 4 patients all of them showed marked improvement. The possible mechanism of the role of indomethacin in VKC is discussed.

Administration, Topical↗