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Biomedical subjects

A N Ansari

Publications and source records attributed to A N Ansari.

At least 19 recordsLinked to original sources
PubMed1997

Gorham's disease of the radius: radiographic, scintigraphic, and MRI findings with pathologic correlation. A case report and review of the literature.

A rare case of Gorham's disease affecting the radius in a 46-year-old woman is presented. It was studied by plain radiography, MRI, and scintigraphy, including three-phase radionuclide bone scan and thallium scan. Three-phase bone scan demonstrated slightly decreased activity in the affected portion of the forearm in the early phase, but showed increased activity on the blood pool and delayed imaging. A thallium scan revealed no abnormalities. Histopathologic examination revealed osteoclastic activity and scar tissue with minimal remaining vasculature.

Female↗
PubMed1997

Rapid detection of acute appendicitis with Tc-99m-labeled intact polyvalent human immune globulin.

BACKGROUND: Acute appendicitis remains problematic for emergency clinicians. A rapid and definitive test is needed for detecting acute appendicitis before surgical intervention. The purpose of this clinical trial was to determine the efficacy of Tc-99m-labeled intact polyvalent human immune globulin (Tc-99m IgG) in the evaluation of acute appendicitis. STUDY DESIGN: Thirty-five patients with clinically suspected acute appendicitis were evaluated with Tc-99m IgG. After the intravenous injection of 25 mCi (92.5 MBq) of Tc-99m IgG, anterior flow, single photon emission computerized tomography (SPECT) and planar delayed images of the abdomen were obtained. Any abnormal focal uptake of Tc-99m IgG in the right lower quadrant was considered to be a positive scan. RESULTS: Twenty-one patients with a positive Tc-99m IgG scan underwent laparotomy and were found to have acute appendicitis. Of the 14 patients who had negative scans, 7 underwent surgery. In this series, Tc-99m IgG study yielded 21 true-positive, 12 true-negative, and 2 false-negative results with a sensitivity, specificity, and accuracy of 91%, 100%, and 94%, respectively. The positive and negative predictive values were 100% and 86%, respectively. There were no false-positive results. CONCLUSIONS: Tc-99m IgG scintigraphy can provide the clinicians a simple, rapid, and definitive test for the diagnosis of acute appendicitis.

Acute Disease↗
PubMed1995

Excess PTH in CRF induces pulmonary calcification, pulmonary hypertension and right ventricular hypertrophy.

Calcification of the lungs occurs in chronic renal failure (CRF) and may adversely affect both pulmonary and right ventricular function. The present study examined the role of excess parathyroid hormone (PTH) in the genesis of pulmonary calcifications in dogs with experimental CRF and evaluated calcium content of lungs, diffusing lung capacity (DCO), mean pulmonary artery pressure (MPAP), right ventricular pressure (RVP), and right ventricular hypertrophy (RVH) in six normal, six with CRF, and six thyroparathyroidectomized (CRF-PTX) dogs. CRF-PTX animals were maintained normocalcemic and euthyroid. The degree and duration of CRF were not different between the two groups with CRF. The mean value of the serum PTH in CRF dogs was 166 +/- 42 microliters Eq/ml, but was undetectable in CRF-PTX animals. Thallium scan provided evidence consistent with RVH in CRF dogs but not in CRF-PTX animals. Calcium content of lungs was markedly elevated in CRF dogs (7656 +/- 1657 mg/kg dry wt) but modestly increased in CRF-PTX (1057 +/- 117 mg/kg dry wt) as compared to normal (673 +/- 34 mg/kg dry wt). RVP and MPAP were significantly (P < 0.01) higher and DCO significantly lower in CRF dogs than in normal or CRF-PTX animals. These parameters were not different in the latter two group of dogs. In three additional dogs with CRF of one year duration which were followed for an additional year after parathyroidectomy, these abnormalities were corrected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Radionuclide imaging in forme fruste of melorheostosis.

Scintigraphy was instrumental in two histologically proven cases of forme fruste melorheostosis. Radionuclide bone scans demonstrated a moderately increased uptake of radiopharmaceutical localized to the "flowing" cortical hyperostosis of melorheostosis observed radiographically. The medullary portion of the affected bones showed no increase in tracer activity. In one case, imaging with Tl-201 chloride demonstrated increased focal activity of the lesion. These scintigraphic findings can help distinguish the mildest manifestation (forme fruste) of melorheostosis from the well-ossified lesions of myositis ossificans and parosteal or periosteal osteosarcoma. The findings of MRI are also described in one patient.

Adult↗
PubMed1994

Direct comparison of Tc-99m DTPA and Tc-99m HMPAO for evaluating brain death.

Portable cerebral perfusion studies provide a quick and accurate alternative to traditional confirmatory examinations (such as four-vessel angiography and electroencephalography) to determine brain death. The authors retrospectively analyzed 26 cerebral perfusion studies using both Tc-99m DTPA and Tc-99m HMPAO. The flow agents gave identical results. Additionally, the delayed-phase Tc-99m HMPAO images gave the same results for brain death (14 positive and 12 negative) as the flow images from either agent. Because the Tc-99m HMPAO delayed images can be used for diagnosis, many technical problems become less crucial. Unlike Tc-99m DTPA, Tc-99m HMPAO normally visualizes the gray matter of the cerebellum, midbrain, and medulla. These areas must be evaluated to ensure that they meet the strict criteria for brain death. These differences and the present study suggest that Tc-99m HMPAO is a superior agent for cerebral perfusion studies to determine brain death.

Adult↗
PubMed1994

Degradation of hyaluronate by the concerted action of ozone and sunlight.

The influence of ozone and sunlight in a concerted reaction on hyaluronate solutions was investigated. The kinematic viscosity of hyaluronate solutions is decreased by ozone-air mixtures and simultaneous radiation with sun rays within a few minutes, indicating a depolymerization of the hyaluronate molecule. The reaction is dependent on the concentration of ozone and on the time of exposure to ozone and sunlight. The concerted degradation of hyaluronate is more effective than the reaction with each component, ozone and sun rays, alone. We conclude that hyaluronate depolymerization by ozone and sunlight may be one factor for irritations of the eye by photochemical smog and increased exposure to sun rays.

Animals↗
PubMed1993

Osteosarcoma presenting as intestinal obstruction.

Osteosarcoma commonly presents with osseous and pulmonary metastases. We present an unusual case of extraosseous metastatic abdominal chondroblastic osteosarcoma presenting as intestinal obstruction.

Abdominal Neoplasms↗
PubMed1990

Circumferential quantitative analysis of planar 201T1 myocardial scintigraphy in the diagnosis of coronary artery disease.

Methodology for the computer analysis of 201T1 myocardial perfusion images has been developed by several laboratories. Substantial evidence of the advantage of this approach over visual inspection alone has been reported. The currently available computer analyses use different algorithms to analyze 201T1 kinetics in the myocardium. The authors evaluated and compared two widely used software programs, Medical Data System (MDS): a mean-count profile, and the Cedars Sinai (CS): a maximal-count profile, of planar 201T1 scintigraphy for their ability to detect coronary artery disease (CAD).

Adult↗
PubMed1988

Gallium-67 uptake in cutaneous lesions of mycosis fungoides.

The literature on gallium imaging in mycosis fungoides is limited and conflicting. A case of mycosis fungoides with increased uptake of Ga-67 in clinically noninfected skin lesions is reported. The literature regarding mycosis fungoides and gallium imaging is reviewed.

Aged↗
PubMed1988

Chronic berylliosis. Demonstration by gallium-67 imaging and magnetic resonance imaging.

Ga-67 is known to localize in the lungs in a wide spectrum of pulmonary pathology. The nonspecific affinity of Ga-67 uptake in both inflammatory and neoplastic entities limits its utility in terms of pulmonary disease differential diagnosis. However, Ga-67 lung imaging has proven to be helpful in evaluating the extent of inflammatory activity, as well as in assessing responses to therapy. A case of active chronic berylliosis, a disorder in which Ga-67 uptake has not been previously reported is presented. There is diffuse bilateral Ga-67 pulmonary activity before therapy. Subsequent to steroid therapy, a marked decrease in pulmonary gallium uptake activity was noted with only residual hilar and mediastinal adenopathy noted.

Adult↗
PubMed1985

Erythrocyte survival in chronic renal failure. Role of secondary hyperparathyroidism.

The human erythrocyte (RBC) is a target organ for parathyroid hormone (PTH) and the hormone increases RBC osmotic fragility and induces their hemolysis. The present study was undertaken to examine whether elevated blood levels of PTH affect RBC survival, and therefore whether PTH, being an extracorpuscular factor, is responsible for the shortened RBC survival in chronic renal failure. 51Cr-labeled RBC survival was elevated in six normal dogs, in six animals with chronic renal failure and secondary hyperparathyroidism (NPX), and in six thyroparathyroidectomized dogs (NPX-TPTX) with comparable degree and duration of chronic renal failure. In the normal dogs, 51Cr-labeled RBC survival ranged between 22 and 35 (25.6 +/- 1.9) d. In the NPX dogs, 51Cr-labeled RBC survival was shortened and the values ranged between 16 and 20 (18.4 +/- 0.6) d, a value significantly (P less than 0.01) lower than normal dogs. In NPX-TPTX dogs, 51Cr-labeled RBC survival ranged between 20 and 33 (25.2 +/- 1.8) d, a value not different from that in normal dogs but significantly higher (P less than 0.01) than that in NPX animals. Our data demonstrate that excess blood levels of PTH and not other consequences of the uremic state are responsible for the shortened RBC survival in chronic renal failure.

Animals↗
PubMed1983

Cyclotron isotopes and radiopharmaceuticals--XXXIII. Synthesis and structural effect of selective biliary excretion of halogenated indotricarbocyanines.

Five indotricarbocyanines of structure I were synthesized and labeled with 131I in the 5 position. The substituent, R, was varied [formula: see text] R = H, F, Cl, Br and I. The dynamics of hepatic uptake and blood clearance of the labeled compounds were determined in mice. Kidney uptake in all cases was negligible. The hepatic excretion displayed 2 components. The initial hepatic disappearance rates of R = H and R = F were 7.3 and 4.5%/min, respectively. The maximum liver activity in mice occurred at 2--5 min and the % remaining in the liver at 0.5 h was 3.6, 8.6, 19, 29 and 47% for R = H, F, Cl, Br and I substitution. It is notable that a small change in the substituent at the 5' position in the molecule has such a pronounced effect. Whether electronic and/or steric effects are controlling the mechanism of hepatobiliary clearance is not obvious. A correlation of the liver activity with the covalent radius of R was noted. The comparative studies were at an injected dose of 0.4--0.6 mumol/kg, and typically at a specific activity of 200 mCi/mol. Loading dose effects were not appreciable under these conditions. Scintigraphic results are reported for dogs and a rabbit. The results suggest that indotricarbocyanines of structure (I) labeled with 123I or with 18F are potential radiopharmaceuticals for dynamic hepatobiliary function studies.

Animals↗
PubMed1981

Comparison of airway closure measured in vivo and from single-breath washout curve.

The volume of air trapped (Vat) in alveoli subtended by airways closed at residual volume (RV) was correlated with the volume of air left in the lungs at the start of airway closure (CC) in a clinical study of 13 patients with a variety of pulmonary disorders and 5 normal subjects. Vat was quantitated at RV from the in vivo distribution differences between 127Xe inspired as a bolus and again after equilibrium; CC was measured from the inflection point on the single-breath washout curve at the onset of phase IV. 127Xe activity was measured with a scintillation camera, and activity profiles were obtained for 28-45 consecutive 6.5-mm horizontal lung slices between base and apex. Three well-defined regions were found: A, in the upper lung, all of whose airways remained completely open; B, located above the base and containing both open and closed airways; and C, above the base, all of whose airways were closed. Of the Vat of 0.43 liter for the normals, 41% was located in region C. For the patients, the values were 59% of 0.59 liter. The relationship between the onset of phase IV and regional airway closure was confirmed for normals as well as patients. A statistically significant increase in closure was found for the patients over the normals. Excellent agreement was obtained between Vat/TLC (total lung capacity) and CC/TLC (r = 0.79, P less than 0.001) for normals as well as patients, and CC appears to reflect regional airway closure in both health and disease. Similar excellent agreement was obtained for the normals between lung height with closed airways and CC/TLC (r = 0.88, P less than 0.001). Vat appears to be the most important physiological determinant of phase IV, the value at RV representing the limiting case.

Adult↗
PubMed1980

A comparison of Tc-99m-labeled human serum albumin and in vitro labeled red blood cells for blood pool studies.

A comparison of Tc-99m-labeled human serum albumin (HSA) and in vitro labeled red blood cells (RBC) was carried out in five subjects. The disappearance of radioactivity from the blood was more rapid for HSA (T 1/2, 281.6 minutes, range 202.1--318.3) than for RBC (T 1/2, 1719.8 minutes, range 767.6--5059.5). Urinary excretion was twice as great for HSA. Ratios of activity in heart blood pool to lung and liver were considerably greater for RBC up to 2 hours after administration. The results indicate that labeled RBC are superior to labeled HSA for blood pool imaging.

Aged↗