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N Petry

Publications and source records attributed to N Petry.

12 recordsLinked to original sources
PubMed1997

Abnormal Tl-201 myocardial scintigraphy associated with administration of sodium aurothiomalate.

A patient with strikingly reduced Tl-201 myocardial retention after intramuscular administration of gold therapy (sodium aurothiomalate) is described. Following a routine Bruce protocol exercise test, postexercise scintigraphy was normal; an abnormal scan of the thorax was obtained on delayed imaging at 3 hours. This scan showed no demonstrable myocardial retention of tracer. In between the two acquisitions, the patient received 50 mg intramuscular sodium aurothiomalate for rheumatoid arthritis. A repeat scan obtained 3 days later showed a normal myocardial scintigram. It is recommended that patients receiving intramuscular gold therapy should not undergo such treatment close to the timing of Tl-201 myocardial scans.

Antirheumatic Agents↗
PubMed1993

Time sampling observation procedure for studying drug effects: interaction between d-amphetamine and selective dopamine receptor antagonists in the rat.

A rapid time sampling observation procedure combined with two forms of automatic activity assessment is described. The methods are illustrated by examination of the behavioral effects of d-amphetamine, administered to rats either alone or in combination with antagonists selective for D1 or D2 dopamine (DA) receptors. Low doses of d-amphetamine (0.5-4.0 mg/kg) increased photocell counts, rearing, ambulation, and various forms of sniffing. Similar effects were observed in the first 30 min following administration of 8.0 mg/kg d-amphetamine. However, animals exhibited licking, intense sniffing down, and repetitive head and limb movements in the following 30 min; minimal ambulation, rearing, and sniffing up were observed. The "traditional" total photocell count measure did not differentiate between these time-dependent changes in locomotion. On the other hand, latch counts-where subjects had to move between the beams to register a count-adequately demonstrated this change in locomotion. The selective D1 receptor antagonist SCH23390 and selective D2 antagonist raclopride dose dependently inhibited the behavioral changes produced by 1.5 mg/kg d-amphetamine. Higher doses of SCH23390, but not raclopride, produced a behavioral pattern indistinguishable from that observed in control sessions. Both DA antagonists equipotently blocked the intense sniffing down and repetitive head/body movements produced by 8.0 mg/kg d-amphetamine. A narrow intermediate range of doses of SCH23390 reduced the incidences of these behaviors and produced levels of locomotion and sniffing straight that were significantly higher than those observed in control session. This form of behavioral activation was not observed with raclopride. Therefore, this observation procedure revealed subtle differences between the inhibitory effects of SCH23390 and raclopride on d-amphetamine-induced behavioral changes.

Animals↗
PubMed1992

The relationship between myocardial retention of technetium-99m teboroxime and myocardial blood flow.

OBJECTIVES: The aim of this study was to define the temporal changes in the relationship between technetium-99m teboroxime tissue retention and myocardial blood flow in a canine model. BACKGROUND: Technetium-99m teboroxime is a new neutral lipophilic myocardial perfusion agent. It is known to be highly extracted by the myocardium but to have a rapid clearance rate. METHODS: A wide range of myocardial blood flow was induced in each experiment by regional coronary occlusion and dipyridamole infusion. Myocardial retention of technetium-99m teboroxime was determined by in vitro tissue counting at 1, 2 or 5 min after injection of the tracer. Tracer retention was correlated with microsphere-determined blood flow and the data were fitted to nonlinear functions. RESULTS: Correlation coefficients for these functions were 0.92, 0.95 and 0.95 at 1, 2, and 5 min, respectively. At 1 min after injection, the relationship of technetium-99m teboroxime retention to blood flow was linear over a wide flow range, becoming nonlinear at flow rates greater than 4.5 ml/min per g. After 5 min the retention-flow relationship was linear only to 2.5 ml/min per g, above which little change in retention was noted. Normalized myocardial retention, expressed as a percent of the retention at 1 ml/min per g, was also calculated. At flow rates of 1, 2, 3, 4 and 5 ml/min per g, normalized retention was 100, 169, 228, 277 and 317% at 1 min and 100, 171, 217, 239 and 237% at 5 min after injection. CONCLUSIONS: At 1 min after injection, the relationship of technetium-99m teboroxime myocardial retention to blood flow is well maintained over a wide range of flow. However, after only 5 min, tracer retention underestimates flow changes at moderate and high flow rates. Thus, rapid acquisition protocols are necessary to fully exploit the potential of this promising new tracer in the evaluation of myocardial perfusion.

Animals↗
PubMed1992

The kinetics of copper-62-PTSM in the normal human heart.

Copper-62-labeled pyruvaldehyde bis(N-4-methylthiosemicarbazone) copper(II) (PTSM) is a generator-produced myocardial perfusion tracer. Animal studies have shown high myocardial tissue extraction and prolonged retention. The aim of this study was to define myocardial kinetics of 62Cu-PTSM and to determine its suitability for evaluating myocardial perfusion at rest and during pharmacological vasodilation in human subjects. In six healthy volunteers, 62Cu-PTSM was administered at baseline and during a 6-min adenosine infusion (140 micrograms/kg/min). Dynamic PET imaging with high temporal resolution was performed over 20 min. Good image quality was observed at rest and following adenosine. Myocardial kinetics demonstrated prolonged tissue retention with a clearance half-life of 105 +/- 49 min at rest and 101 +/- 65 min following adenosine (p = ns). Copper-62-PTSM tissue retention was quantified and showed only a 1.97-fold increase from rest to adenosine studies. This suggests attenuation of tracer retention at high flow rates. Copper-62-PTSM represents a promising new radiopharmaceutical for the evaluation of myocardial perfusion in the human heart.

Adenosine↗
PubMed1991

Effects of low, autoreceptor selective doses of dopamine agonists on the discriminative cue and locomotor hyperactivity produced by d-amphetamine.

The ability of low doses of the dopamine (DA) agonists quinpirole and (+)-3-PPP to reduce the discriminative stimulus properties and locomotor hyperactivity produced by d-amphetamine (0.5 mg/kg) was assessed in two groups of rats. Quinpirole (0.0125-0.05 mg/kg) and (+)-3-PPP (1.0-2.0 mg/kg) completely antagonized d-amphetamine-induced locomotor hyperactivity. In contrast, only single doses of quinpirole (0.025 mg/kg) and (+)-3-PPP (2.0 mg/kg) were effective in the drug discrimination paradigm; the antagonisms were small (18-47%), but significant. The inhibitory effects of quinpirole and (+)-3-PPP in these behavioural models are probably due to their ability to selectively stimulate DA autoreceptors in the nucleus accumbens and reduce the increase in DA release produced by d-amphetamine. It is suggested that the much weaker effects of the drugs in the discrimination paradigm are due to changes produced by the long-term periodic administration of d-amphetamine to these animals, such as a down-regulation in the sensitivity of DA autoreceptors.

Animals↗
PubMed1991

Behavioural profile of partial D2 dopamine receptor agonists. 1. Atypical inhibition of d-amphetamine-induced locomotor hyperactivity and stereotypy.

The effects of partial D2 dopamine (DA) receptor agonists on the behavioural activation produced by 1.5 and 8.0 mg/kg d-amphetamine were compared with the changes produced by the classical DA antagonist haloperidol. Alterations in behaviour were assessed in standard activity monitoring cages by direct observation of the rats using a rapid time sampling procedure. Haloperidol blocked d-amphetamine (1.5 mg/kg)-induced increases in photocell counts, ambulation, rearing and sniffing up, and after the highest dose of the DA antagonist the animals were mainly inactive. The partial D2 DA agonist SDZ 208-911 was equipotent to haloperidol in blocking the increase in photocell counts and rearing produced by d-amphetamine. However, even high doses of the drug did not reduce the incidence of sniffing or induce inactivity, but qualitative changes in the form of sniffing did occur. Although considerably less potent, preclamol exerted similar effects to SDZ 208-911. The profiles of SDZ 208-912 and terguride were intermediary to those of SDZ 208-911 and haloperidol. All compounds blocked the repetitive sniffing down produced by 8.0 mg/kg d-amphetamine. After a low dose of haloperidol, these stereotyped behaviours were replaced by a behavioural syndrome similar to that observed with low dose d-amphetamine, but inactivity was observed following a further small increase in antagonist dose. The blockade of stereotypy by SDZ 208-911, preclamol and terguride was accompanied only by the low dose d-amphetamine behavioural syndrome; no inhibition of sniffing or induction of inactivity occurred. SDZ 208-912 exhibited a profile with features very similar to that noted with haloperidol. These findings suggest that partial D2 agonists exert similar, but not identical, behavioural effects to classical DA antagonists when dopaminergic function in increased by d-amphetamine. The differences in behavioural profile are discussed in relation to variations in the intrinsic efficacy of the dopaminergic compounds and to differences in the response capability of D2 receptor populations underlying the different behaviours produced by d-amphetamine.

Animals↗
PubMed1985

Phosphorus-32 therapy of cystic Grade IV astrocytomas: technique and preliminary application.

Instillation of [32P]chromic phosphate to cystic brain tumors was performed in six patients. Three patients had craniopharyngioma, two had Grade IV astrocytoma and one had Grade II astrocytoma. The cyst volumes ranged from 2 to 44 cc. A calculated dose of 20,000 rad was delivered to the cyst wall. The [32P]chromic phosphate dose given to achieve this dose ranged from 0.11 mCi to 2.5 mCi. Radionuclide leakage was not detected in either the central nervous system or the reticuloendothelial system by bremsstrahlung scanning. Stereotactic instillation was done in some cases, others had indwelling catheters. The frequency of cyst fluid aspiration in the three patients with craniopharyngioma decreased postinstillation. In the two patients with Grade IV astrocytoma, reductions in both the CT documented cyst size as well as the frequency of cyst aspiration were noted. We conclude that [32P]chromic phosphate installation by stereotactic or indwelling catheter method is a safe and helpful procedure in the management of cystic brain tumors.

Adult↗
PubMed1985

Indium 111 platelet imaging for the detection of deep venous thrombosis and pulmonary embolism in patients without symptoms after surgery.

Indium 111 platelet imaging for the detection of deep vein thrombosis and pulmonary emboli was performed in 171 patients after abdominal and pelvic surgery. Fifteen patients were found to have inadequate circulating blood pools of indium 111 platelets, making the study nondiagnostic. Of 156 patients with technically satisfactory images, 46 (29.5%) had images consistent with deep venous thrombosis and/or pulmonary emboli. The incidence, time of occurrence, and location of thromboemboli was similar to those of other reports of postoperative patients groups studied by iodine 125 fibrinogen uptake testing. Eighty patients had normal indium 111 platelets and 30 patients had diffusely distributed indium 111 platelets found in the operative field, suggesting accumulation in a postoperative hematoma. None of these results was confused with a diagnosis of deep venous thrombosis. When compared with another accurate diagnostic test in 23 patients, indium 111 platelet imaging was found to have a sensitivity of 100% and specificity of 90%. The technique of indium 111 platelet imaging is performed easily in patients after surgery with some limitations as to the use of donor platelets and the occasionally altered imaging of the operative site. This diagnostic technique enjoys the distinct advantage in that it allows surveillance of the legs, pelvis, abdomen, and chest by a single method, making it a near-ideal method of postoperative thromboembolism surveillance.

Blood Platelets↗
PubMed1982

Muscarinic cholinergic receptor binding: in vivo depiction using single photon emission computed tomography and radioiodinated quinuclidinyl benzilate.

An attempt was made to characterize, in vivo, specific binding to the muscarinic cholinergic receptor in the calf using the radioiodinated ligand quinuclidinyl benzilate (123I-OH-QNB) and single photon detection emission computed tomography (SPECT). The supratentorial brain activity was significantly increased after the intravenous infusion of 123I-OH-QNB as compared to free 123I. Scopolamine, a muscarinic cholinergic receptor antagonist, decreased the measured brain activity when infused prior to 123I-OH-QNB consistent with pharmacologic blockade of specific receptor binding. Quantitative in vitro tissue distribution studies obtained following SPECT imaging were consistent with regionally distinct specific receptor binding in the striatum and cortical gray matter, nonspecific binding in the cerebellum, and pharmacologic blockade of specific binding sites with scopolamine. Although 123I-OH-QNB is not the ideal radioligand, our limited success will hopefully encourage the development of improved binding probes for SPECT imaging and quantitation.

Animals↗
PubMed1980

Nonradioactive iodoantipyrine enhanced cranial computed tomography: preliminary observations.

Nonradioactive 4-iodoantipyrine, an iodinated indicator that freely diffuses across the blood-brain barrier, was serially imaged in vivo using computed tomography (CT). Prominent enhancement was immediately detected in the brain substance of the dog following the intracarotid injection of this contrast medium. An estimate was made of the brain:blood partition coefficient for 4-iodoantipyrine from the CT derived arterial and brain concentration of this iodinated marker. Practical applicability of this technique is limited unless an improved method for getting the 4-iodoantipyrine into solution can be developed. However, this study reinforces the concept that local cerebral blood flow and metabolism can be analyzed by diffusible tracers using CT.

Animals↗
PubMedDate not supplied

In vivo quantitation of regional cerebral blood flow in glioma and cerebral infarction: validation of the HIPDm-SPECT method.

Iodine-123 labeled hydroxyiodopropyldiamine (HIPDm) is a diffusible indicator with an 85%-90% extraction fraction and stable retention in the brain for more than 2 hr. Equilibrium-phase imaging and quantitation using single-photon emission computed tomographic (SPECT) scanning defined a distribution of HIPDm in proportion to regional cerebral blood flow (rCBF). Studies in calves affirmed a close correspondence (r = 0.97) in calculated rCBF between HIPDm and microspheres using the tissue deposition-arterial input function microsphere methodology. Using this same mathematical analysis in vivo, reproducible rCBF data within the expected range of normal were obtained on repeated studies in the same nonhuman primate. With a diffuse encephalopathy secondary to subarachnoid blood, a bilaterally symmetric decrease in rCBF was present. A prominent focal decrease in HIPDm accumulation and calculated rCBF was noted with cerebral infarction in the distribution of a ligated middle cerebral artery. Patient studies with glioma revealed diminished HIPDm accumulation due to decreased flow and/or pH in the region of the neoplasm as well as in the associated vasogenic edema and overlying gray matter.

Animals↗