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Biomedical subjects

J L Doppman

Publications and source records attributed to J L Doppman.

At least 235 records · Page 13Linked to original sources
PubMed1985

Constrictive pericardial disease: prognostic significance of a nonvisualized left ventricular wall.

Twenty-six patients with pericardial constriction confirmed by catheterization were studied by dynamic computed tomography (CT). The posterolateral wall of the left ventricular myocardium was not detected in five patients (19.2%). None had evidence of previous myocardial infarction on electrocardiogram or levocardiogram. In 16 patients, a pericardiectomy was performed to remove pericardial constriction. All five patients with nondetectable posterolateral walls of the left ventricle died at or immediately following surgery because of acute myocardial failure. Nonvisualization of the posterolateral wall of the left ventricle in patients with constrictive pericarditis suggests the presence of myocardial fibrosis or atrophy. Surgery is an extremely high risk in these patients.

Adult↗
PubMed1985

Tumors and arteriovenous malformations of the spinal cord: assessment using MR.

Thirty-three patients with either primary spinal cord tumors (n = 18), intradural tumors excavating into the cord (n = 9), or spinal arteriovenous malformations (AVM) (n = 6) were studied with magnetic resonance (MR) imaging. In 25 of 38 examinations (66%) (five patients were studied twice), MR provided more information than that provided by other neuroradiologic procedures. In several cases, MR affected patient management decisions. Advantages of MR, in addition to the absence of ionizing radiation and its noninvasive nature, include good spinal cord-CSF-theca contrast, lack of bone-derived artifacts, ease of multiplanar imaging, improved discrimination between intra- and extramedullary lesions, better definition of tumoral cavities and possible distinction from true syringes, ability to help one recognize thrombus formation within an AVM, and ease of follow-up of cord lesions for possible size changes. Apart from factors precluding the study in several patients (life support systems, pacemakers, claustrophobia, neurovascular clips), disadvantages of MR imaging include motion artifacts (prevalent in thoracolumbar area), poor capability of typing and grading of tumors, potential of false-positive results, poor detection of calcification, and poor delineation of feeders and drainers of AVM.

Adolescent↗
PubMed1985

Parathymic parathyroid: CT, US, and angiographic findings.

Six patients with primary hyperparathyroidism caused by an undescended parathymic adenoma are described. All glands were anterior to the common carotid artery at the level of the hyoid bone. Blood supply was from the superior thyroid artery, and venous drainage was into the superior thyroid vein. Ultrasound (one of five) and computed tomography (two of six) were rarely positive, but glands can be detected with both modalities if the examination is carried high enough. Glands within the carotid sheath are generally lower in the neck and have a blood supply from the inferior thyroid artery with drainage into the vertebral veins.

Adenoma↗
PubMed1985

MR cisternography and myelography with Gd-DTPA in monkeys.

To enhance the contrast between cerebrospinal fluid (CSF), brain, spinal cord, and surrounding meninges and bone on magnetic resonance (MR) images, as well as to study CSF flow, gadolinium-DTPA was injected in the subarachnoid space of eight monkeys. Six doses of progressively higher concentrations (from .125 mmol to 250 mmol) were injected every 30-40 minutes. Images of head and spine were obtained at .26 T or .5 T in sagittal and axial planes, using both spin-echo and inversion-recovery sequences in 13 imaging experiments. Marked, consistent changes of signal intensity in the CSF cavities were observed following the injections. These changes were dose related and occurred at different times in the areas close to the injection site versus those distant, a disparity that obviously was related to CSF flow. Gd-DTPA cisternography and myelography may be valuable in MR imaging of central nervous system disease, such as tumors adjacent to the CSF cavities, abnormal CSF collections (e.g., arachnoidal cysts), CSF rhinorrhea and otorrhea, syringohydromyelia, and studies of hydrocephalus and CSF flow dynamics.

Animals↗
PubMed1985

Absence of intercavernous venous mixing: evidence supporting lateralization of pituitary microadenomas by venous sampling.

Preoperative lateralization of endocrine-active pituitary tumors may be possible by bilateral inferior petrosal sinus (IPS) sampling for hormone measurement. The reliability of this technique depends on unilateral drainage of blood from the adenoma within the pituitary gland, in its course from the gland to the ipsilateral cavernous sinus, and from the cavernous sinus to the junction of the IPS and the internal jugular vein. Anatomical studies demonstrate unilateral drainage of each hemihypophysis into the ipsilateral cavernous sinus. The degree of mixing of blood between the cavernous sinuses, via the intercavernous sinus, and between the IPSs, via the basilar plexus, is unknown. We determined the extent of mixing of blood flowing from the superior orbital vein to the junction of the IPS and the internal jugular vein in four rhesus monkeys. After catheterization of a superior orbital vein and both IPSs, 99Tc-colloidal sulfur was infused into the superior orbital vein while blood samples were taken simultaneously from both IPSs and a peripheral vein at 3-min intervals. Mean relative radioactivity was 100 +/- 14% (+/- SEM) in the ipsilateral IPS, 8 +/- 2% in the contralateral IPS, and 3 +/- 1% in a peripheral vein. Isotope reaching the ipsilateral IPS before recirculation from the periphery was 10- to 313-fold more concentrated than in the contralateral IPS. These findings suggest that mixture of blood between the cavernous sinuses and between the IPSs is insignificant and support the capability of preoperative lateralization of pituitary microadenomas by bilateral and simultaneous IPS sampling.

Adenoma↗
PubMed1985

Aspiration of blood from the jugular vein during intracarotid drug infusion in monkeys. Implications for extracorporeal drug removal.

Circulation of blood in the ipsilateral jugular vein through an extracorporeal circuit for drug removal during intracarotid chemotherapy has recently been reported to decrease the systemic drug exposure. The reduced systemic exposure achieved by the use of this technique should permit a several-fold increase of the intracarotid dose of chemotherapy without increasing systemic toxicity. To determine the influence of the rate of blood removal from the jugular vein on the fraction of the blood flowing through the ipsilateral internal carotid artery (ICA) collected for extracorporeal drug removal, the authors aspirated blood from the jugular bulb into an extracorporeal circuit at varying rates during a constant infusion of the indicator dye, indocyanine green (ICG), into the ICA of rhesus monkeys. The fraction of the ipsilateral carotid blood channeled into the extracorporeal circuit increased linearly with the rate of aspiration of jugular blood. This suggests that the absence of valves in the intracranial venous system should permit increasing fractions of drug removal during intracarotid infusion by increasing the rate of collection of venous blood from the ipsilateral jugular bulb. The measurement of ICG concentrations in a similar manner in patients undergoing isolated perfusion may prove to be a clinically useful method for estimating the maximum safe dose in high-dose intra-arterial chemotherapy.

Animals↗
PubMed1985

Reduced systemic drug exposure by combining intra-arterial chemotherapy with hemoperfusion of regional venous drainage.

Four patients with malignant cerebral gliomas received 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) into the internal carotid artery (ICA) while the ipsilateral jugular drainage was pumped extracorporeally through a hemoperfusion cartridge containing a nonionic adsorbant resin. Each patient received 220 mg/sq m BCNU, infused over 45 minutes through a toposcopic catheter positioned with the tip in the ICA beyond the origin of the ophthalmic artery. Jugular blood was pumped extracorporeally at 300 ml/min through a large-bore catheter in the jugular bulb. Plasma samples were obtained for BCNU measurement at frequent intervals from the right atrium. During a separate treatment, 6 weeks before or after the hemoperfusion treatment, the same dose of BCNU was infused into the ICA and atrial samples were obtained on a similar schedule. Hemoperfusion of the jugular blood during intracarotid infusion reduced the systemic exposure by 56% to 87% and increased total body clearance of BCNU by two- to eightfold. The calculated pharmacokinetic advantage (brain:body exposure ratio) was between 21 and 55:1 when the combined treatment was used.

Adolescent↗
PubMed1985

Localization of an occult insulinoma by intraoperative ultrasonography.

Intraoperative ultrasonography has not been used previously to locate an insulinoma that was not surgically palpable or that could not be seen by selective arteriography. In this report we described a patient with an insulinoma localized to the pancreatic head identified by transhepatic portal venous sampling but not by selective arteriography or palpation. At operation intraoperative ultrasonography demonstrated an 8 mm tumor in the pancreatic head and guided the successful enucleation.

Adenoma, Islet Cell↗
PubMed1985

Arterial drug infusion with extracorporeal removal. II. Internal carotid carmustine in the rhesus monkey.

During cancer chemotherapy by intra-arterial drug administration, systemic toxicity often limits the tolerable dose. We evaluated the pharmacokinetic advantage obtained by infusing carmustine (BCNU) into the internal carotid artery during BCNU removal from the blood from the perfused region by hemoperfusion. A hemoperfusion column (XR-010, Extracorporeal Medical Specialties) was shown to remove BCNU quantitatively from sheep blood flowing at 300 ml/minute when the drug was infused at 13 mg/minute for 30 minutes. Under general anesthesia, adult rhesus monkeys underwent catheterization of the internal carotid artery and placement of a catheter in the ipsilateral jugular vein at its junction with the sigmoid sinus. BCNU (10 mg/kg) was infused over 20 minutes while blood was pumped from the jugular vein through a small column and back into the inferior vena cava. The procedure reduced systemic exposure by 46%-84% compared with iv infusion of the same dose. Brain-to-systemic exposure ratios ranged from 18:1 to 87:1, depending on the pump flow rate and method of calculation. Hematopoietic toxicity was prevented. It is suggested that tumor exposure to BCNU comparable to that associated with very high tumor cell kill in vitro may be feasible with little or no systemic toxicity.

Animals↗
PubMed1984

Improved detection of focal lesions with computerized tomographic examination of the liver using ethiodized oil emulsion (EOE-13) liver contrast.

A prospective study of computerized tomography (CT) of the liver using a liver contrast agent compared to conventional CT was undertaken. CT scanning without contrast agents (NC-CT), CT with water-soluble contrast (WSC-CT), and CT with ethiodized oil emulsion (EOE-CT) were performed on patients with possible or probable hepatic metastases. The findings on these three examinations were compared to the objective findings at surgery in 53 patients. Accuracy of these examinations was 80.7% for NC-CT, 77.1% for WSC-CT, and 84.9% for EOE-CT. The true-positive percentage for 129 hepatic lesions was 40.6% for the NC-CT, 33.6% for WSC-CT, and 76.7% for the EOE-CT. Eighty-three percent (44/53) of 1- to 2-cm liver lesions were detected by EOE-CT, whereas only 26.4% (14/53) lesions of this size were detected by the NC-CT and 20.4% (10/49) shown by WSC-CT. The likelihood that a lesion seen by CT scan was malignant was 84.6% for NC-CT, 89.4% for WSC-CT, and 81.8% for EOE-CT. The EOE contrast agent improves the sensitivity of liver CT for detecting hepatic metastases. The improvement occurs with lesions 1 cm and greater in diameter, but is particularly striking for lesions of 1 to 2 cm in diameter.

Ethiodized Oil↗
PubMed1984

Ultrasonic parathyroid localisation in previously operated patients.

Sixty-two patients with hyperparathyroidism and failed prior neck surgery were examined by ultrasound before reoperation to localise abnormally enlarged glands. If mediastinal lesions are excluded, a total of 57 glands greater than 5 mm in size were removed from 48 patients. Ultrasound demonstrated only 18 of these for a true positive rate of 32%. There were 39/57 (68%) false negatives. In addition, there were 16 false positives. In our experience, the detection rate of ultrasound for enlarged parathyroid glands in patients with failed surgery is significantly less than that reported in previously unoperated patients (73%), or in the limited number of reported cases of patients with previous operations (75%). Our high false negative rate is probably partially due to the large number of posteriorly located small glands which cannot be adequately visualised by ultrasound. Nevertheless, because of its non-invasive nature, low cost and ready availability, ultrasound should be utilised as an initial screening procedure in patients with failed previous surgery.

Adolescent↗
PubMed1984

Measurement of blood-brain barrier permeability with positron emission tomography and [68Ga]EDTA.

Positron emission tomography (PET) was employed to examine time-dependent changes in blood-brain barrier (BBB) permeability to [68Ga]ethylenediaminetetraacetate (EDTA) in the rhesus monkey, following reversible barrier opening by intracarotid infusion of a hypertonic mannitol solution. The PET technique, when combined with measurements of plasma radioactivity, provided a quantitative measure of the cerebrovascular permeability-area product (PA) at different times following mannitol infusion. Hypertonic mannitol treatment reversibly increased PA to [68Ga]EDTA more than 10-fold; much of the barrier effect was over by 10 min after mannitol treatment. The results show that PET can be used to measure transient changes in BBB integrity in specific brain regions, under in vivo, noninvasive conditions.

Animals↗
PubMed1984

Intraoperative urinary cyclic adenosine monophosphate as a guide to successful reoperative parathyroidectomy.

Sixty patients with persistent or recurrent primary hyperparathyroidism underwent reexploration during which urinary cyclic adenosine monophosphate (UcAMP) levels were determined at half-hour intervals by radioimmunoassay. Retrospective analysis of the data allowed us to develop UcAMP criteria for surgical success. Following removal of parathyroid tissue, if an individual UcAMP level dropped 50% from the median baseline level, or if elevated levels dropped to less than 4.0 nmol/dl glomerular filtrate, surgery was predicted to be successful. Eight unsuccessful procedures in seven patients produced no decline in UcAMP, and the intraoperative results accurately predicted surgical failure. Fifty-three patients underwent successful procedures and in every case UcAMP fell. Ninety-eight per cent of these successful procedures were predicted by our criteria. Levels of UcAMP fell 1.5 +/- 0.5 hours (means +/- SD) following abnormal parathyroidectomy. In 19 of 36 successful cases diagnosed before surgery as adenoma, the operative procedure was terminated before a significant drop in UcAMP. In 16 of 17 successful cases diagnosed before surgery as hyperplasia or uncertain histology, UcAMP fell during the operation. Intraoperative determination of UcAMP is helpful in reoperative parathyroid surgery. The criteria established allow intraoperative prediction of success with remarkable accuracy. Urinary cyclic AMP is especially helpful in reoperation for multigland disease; when enough pathologic tissue has been removed, the criteria will be met and the procedure may be terminated with confidence.

Cyclic AMP↗
PubMed1984

Removal of gastrinomas for control of Zollinger-Ellison syndrome.

There are two distinct problems in patients with Zollinger-Ellison Syndrome (ZES): peptic ulcer diathesis and malignant tumors. Antisecretory drugs have allowed us to control the ulcer symptoms and acid output in 45 patients with ZES. We report here the initial seven patients selected for surgical exploration with the goal of removing their gastrinomas. Prior to surgery, an extensive and rigorous protocol to localize the gastrinoma was carried out, including hypotonic duodenography, abdominal ultrasonography, selective arteriography, portal vein sampling for gastrin, and computerized tomography. With this protocol of radiographic localization, gastrinomas were found in two of the seven cases and the syndrome was "cured" in three of the seven patients. The results also demonstrate that preoperative localization is not a substitute for careful surgical exploration as tumors were found in two patients in whom localization failed.

Adult↗