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Biomedical subjects

S B Perlman

Publications and source records attributed to S B Perlman.

15 recordsLinked to original sources

Visualization of dopamine nerve terminals by positron tomography using [18F]fluoro-beta-fluoromethylene-m-tyrosine.

[18F]-6-Fluoro-beta-fluoromethylene-m-tyrosine ([18F]FFMMT) was evaluated as a potential imaging agent for dopamine nerve terminals using positron emission tomography (PET). Biodistribution and time course of this tracer in mice after i.p. injection was consistent with the distribution of dopamine. PET imaging studies involving rhesus macaques showed specific uptake in the dopamine-rich caudate-putamen region. This specific localization was blocked by inhibiting the enzyme L-aromatic amino acid decarboxylase and the transport of the tracer into brain was shown to be stereospecific. These results show the promise of L-[18F]FFMMT as a PET tracer in monitoring degeneration of the CNS dopamine system.

Animals

Radionuclide ventriculography in severely underweight anorexia nervosa patients before and during refeeding therapy.

Congestive heart failure is a well-recognized complication of refeeding therapy in underweight patients with anorexia nervosa but there are few data describing cardiac function during the critical refeeding period. This prospective study examined left ventricular function with conventional electrocardiographic-gated radionuclide ventriculography (RVG) in severely underweight anorexia nervosa patients both before and during refeeding therapy. Eight patients underwent rest and exercise RVG at admission and after regaining approximately 5% to 10% of their ideal body weight. With the admission study serving as a control, the left ventricular ejection fraction and regional wall motion analysis were analyzed before and after refeeding and weight gain. Resting left ventricular ejection fractions were not significantly different between the first and second RVGs (64 +/- 11% vs. 62 +/- 8%, respectively; P greater than .05). Likewise, the left ventricular ejection fraction with maximal exercise did not significantly differ when comparing the first or the second RVG (74 +/- 10% vs. 72 +/- 8%, P greater than .05). During the baseline RVG, the left ventricular ejection fraction increased from 64 +/- 11% (rest) to 74 +/- 10% (maximal exercise) (P less than .001). During the second RVG, the ejection fraction increased from 62 +/- 8% (rest) to 72 +/- 8% (maximal exercise) (P = .003). However, the left ventricular exercise ejection fraction in the second RVG in one patient increased only by one absolute percentage point. Four of the eight patients had regional wall motion abnormalities detected during resting and/or exercise RVG. Abnormal cardiac function occurs in asymptomatic patients with anorexia nervosa undergoing refeeding therapy.

Adolescent

Early detection of rejection in pancreas transplantation.

A major dilemma in pancreas transplantation is the lack of reliable methods for the early detection of allograft rejection. Over a 26-mo period, 70 rejection episodes occurred in 36 patients (13 isolated-pancreas, 23 simultaneous pancreas-kidney recipients) with pancreaticoduodenocystostomy. A total of 300 radionuclide pancreas examinations were performed (mean 8.3/patient) utilizing 99mTc-labeled DTPA. Computer analysis generated a quantitative measure of blood flow to the allograft (technetium index, TI). Rejection episodes were defined as isolated pancreas, isolated kidney, or combined pancreas-kidney. Mean urinary amylase (UA) levels and TI during normal allograft function were 30,256 U/L and 0.57%, respectively, whereas levels heralding rejection were 6873 U/L and 0.39% (P less than .05). The treatment of rejection based on kidney dysfunction or combined pancreas-kidney dysfunction resulted in significantly higher graft salvage and a lower incidence of hyperglycemia compared with isolated-pancreas-allograft rejection. After therapy, a TI greater than 0.3% was associated with 95.9% graft survival, whereas levels less than 0.3% resulted in a 72.7% rate of graft loss (P less than .001). Similarly, pancreas allografts with a UA greater than 10,000 U/L had 92.2% functional survival, whereas levels less than 10,000 U/L resulted in a 53.3% rate of graft loss (P less than 0.001). Overall, reversal of rejection occurred in 80% of cases, with 10 pancreas and 2 kidney allografts lost due to rejection. Monitoring pancreas-allograft function by UA, TI, and renal function in simultaneous transplants allows for the timely diagnosis and successful treatment of pancreas-allograft rejection.

Adult

Clinical outcome of patients with a 'low probability' of pulmonary embolism on ventilation-perfusion lung scan.

Lung ventilation and perfusion (V/Q) scintigraphy is usually indicated when pulmonary embolism (PE) is a suspected diagnosis. Typically, V/Q scintigraphic interpretation is reported as a "normal," "low," "intermediate," or "high probability" of PE. Although a "low probability" interpretation does not exclude the diagnosis of PE, it significantly reduces the likelihood. We retrospectively analyzed up to one year of follow-up in 90 patients who were clinically suspected of having PE, but in whom V/Q scintigraphy implied a low probability of PE. None of the 90 patients demonstrated clinical evidence of PE subsequent to the V/Q scan. Our findings suggest that significant pulmonary embolism is uncommon and that the clinical course appears to be predictable in patients with a low probability V/Q scan.

Follow-Up Studies

Early diagnosis and treatment of pancreas allograft rejection.

A major problem in vascularized pancreas transplantation is the lack of reliable methods for the early diagnosis and effective treatment of allograft rejection. Over a 2-year period, 54 rejection episodes occurred in 31 patients (13 isolated pancreas, 18 simultaneous pancreas-kidney recipients) with pancreaticoduodenocystostomy. A total of 253 radionuclide pancreas examinations were performed (mean 8.4 per patient) utilizing 99mtechnetium-DTPA. Computer analysis generated a quantitative measure of blood flow to the allograft caused the technetium index (TI). Rejection episodes were characterized as isolated pancreas (22), combined pancreas-kidney (16), or isolated renal (16) allograft rejection in combined engraftments. The majority of rejection episodes occurred early (within 3 months of transplant, N = 47) and were more responsive than late rejection to anti-rejection therapy (89.4% vs 42.9%, P = 0.01). Mean urinary amylase (UA) levels and TI during normal allograft function were 29,398 U/l and 0.55%, while levels heralding rejection were 6,528 U/l and 0.40%, respectively (P less than 0.05). The treatment of rejection based upon renal dysfunction or combined renal and pancreas dysfunction resulted in significantly higher graft salvage with a lower incidence of hyperglycemia when compared to isolated pancreas allograft rejection. Of the 11 patients who developed hyperglycemia, 8 (72.7%) ultimately lost their pancreas grafts (P less than 0.001). Following therapy, a TI above 0.3% was associated with 97.4% graft survival, while levels below 0.3% resulted in a 70% rate of graft loss (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones

Osteosarcoma arising in Paget's disease of the calvarium.

Paget's disease of the bone occasionally transforms into sarcomatous tumors such as osteosarcoma. While Paget's disease demonstrates markedly increased uptake of bone scanning radiopharmaceutical, osteosarcomas complicating this condition often show decreased uptake. An unusual scan appearance of the osteosarcoma is presented in which the tumor showed intense uptake of the tracer on the bone scan. The extent of the sarcoma as delineated by the bone scan corresponded closely to the size of the lesion as seen on computerized tomography and magnetic resonance imaging and was confirmed at surgery.

Aged

The accumulation of a platelet protein, thrombospondin, at the site of arterial thrombus formation: preliminary report.

There are many methods available for the detection of thrombosis, none of which are noninvasive, rapid and accurate. Thrombospondin is a platelet protein that is present in the developing thrombus and may be an effective substance to use for imaging thrombosis. Vascular stenosis and thrombosis were produced in coronary, carotid and femoral arteries in eleven adult mongrel dogs. 131I labeled thrombospondin was administered to each animal to determine whether the radiotracer accumulated at the site of thrombus formation. The radioactivity per gram of vessels with thrombi was significantly different from the control vessels or whole blood (p = 0.0037 and p = 0.0015, respectively, paired t-test). This preliminary work suggests that iodinated thrombospondin accumulates at the site of thrombus formation. Labeled thrombospondin may be a rapid, safe and accurate method of detecting arterial thrombosis.

Animals

Medical imaging of the parathyroid glands.

In patients with hyperparathyroidism, the detection and localization of parathyroid lesions can aid the surgeon preoperatively and prior to re-exploration if the initial surgery fails. Computed tomography, ultrasound, and radionuclide scintigraphy are currently most commonly used to evaluate the parathyroid glands in patients with hyperparathyroidism. This article will review the experience, techniques, and advantages of these respective imaging modalities in the evaluation of parathyroid lesions.

Adenoma

The rim sign: association with acute cholecystitis.

In a retrospective analysis of 218 hepatobiliary studies in patients clinically suspected of acute cholecystitis, a rim of increased hepatic activity adjacent to the gallbladder fossa (the "rim sign") has been evaluated as a scintigraphic predictor of confirmed acute cholecystitis. Of 28 cases with pathologic confirmation of acute cholecystitis in this series, 17 (60%) demonstrated this sign. When associated with nonvisualization of the gallbladder at 1 hr, the positive predictive value of this photon-intense rim for acute cholecystitis was 94%. When the rim sign was absent, the positive predictive value of nonvisualization of the gallbladder at 1 hr for acute cholecystitis was only 36%. As this sign was always seen during the first hour postinjection, it can, when associated with nonvisualization, reduce the time required for completion of an hepatobiliary examination in suspected acute cholecystitis.

Acute Disease

Hepatitis B in Wisconsin male prisoners: considerations for serologic screening and vaccination.

To develop a protocol for prevention of hepatitis B virus (HBV) transmission in Wisconsin prisons, we interviewed 619 male prisoners at incarceration to obtain information on hepatitis B risk factors. We defined previous infections by the presence of hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), or antibody to hepatitis B core antigen (anti-HBc). Logistic regression was used to develop a model of relative risk (RR) of HBV infection. Use of illicit intravenous (IV) drugs was the most important risk factor because of a high prevalence of IV drug use and an RR which ranged from 2.93-7.47. Other important risk factors were: prior hepatitis or jaundice (RR = 6.28), race (RR = 2.54 for Blacks, RR = 3.28 for Latinos), transfusion (RR = 3.00), and age. Previous imprisonment was not an independent risk factor for HBV, hence selective serologic screening and vaccination of prisoners are justified rather than mass screening and vaccination. Based upon prevalence of hepatitis B markers in subgroups, it is necessary to screen prisoners with prior hepatitis or jaundice, prior transfusion, and users of IV drugs. The identification of HBsAg carriers by such screening could prevent infection of "household" contacts. Users of IV drugs who are susceptible to HBV infection should be vaccinated. The remaining prisoners constitute a low-risk group for HBV infection and do not require serologic screening or vaccination.

Adult

123I-iodoamphetamine SPECT brain imaging in alternating hemiplegia.

Alternating hemiplegia of childhood is an unusual disorder characterized by early onset (occurring before 18 months of age); repeated attacks of hemiplegia involving both sides of the body; other paroxysmal phenomena, such as tonic stiffening, dystonic posturing, choreoathetoid movements, ocular motor abnormalities, and autonomic disturbances, in association with bouts of hemiplegia or occurring independently; and evidence of mental or neurologic deficits. A girl was examined because of left hemiplegia at the age of 16 months. The patient had begun exhibiting episodes of alternating hemiplegia at approximately 4 months of age. They consisted of tonic stiffening and dystonia of the right or left extremities, lasting from 30 min to several hours and followed by residual hemiparesis. They were invariably accompanied by ocular motor abnormalities. Magnetic resonance imaging, computed tomography, and angiography all were normal. Single proton emission computed tomography brain images during an acute episode of right hemiplegia demonstrated hypoperfusion of the left cerebral hemisphere. Following improvement of the hemiplegia, the patient was re-evaluated. The uptake of the radiotracer in the left hemisphere was increased. The scan did not demonstrate significant asymmetry in cerebral perfusion.

Amphetamines