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Biomedical subjects

J L Doppman

Publications and source records attributed to J L Doppman.

At least 217 records · Page 12Linked to original sources
PubMed1986

Prospective study of gastrinoma localization and resection in patients with Zollinger-Ellison syndrome.

In 1982, a prospective study was initiated of 52 consecutive patients with proven Zollinger-Ellison syndrome (ZES), involving surgical exploration with the goal of removing the gastrinoma after an extensive protocol to localize the tumor. Each patient underwent ultrasound, computed tomography (CT) with oral/intravenous (IV) contrast, and selective arteriography. Eighteen patients had metastatic disease identified by imaging studies and confirmed by percutaneous biopsies, and two patients had multiple endocrine neoplasia type I (MEN-I) with negative imaging studies; therefore, these 20 patients did not undergo laparotomy. Each of the remaining 32 patients (3 with MEN-I and positive imaging studies) underwent laparotomy, and gastrinomas were removed in 20 patients. Preoperative ultrasound localized tumors in 20% of patients, CT in 40%, arteriography in 60%, and any of the modalities in 70% of patients. Infusion CT and arteriography were 100% specific. In 18 patients with either negative imaging (17) or false-positive imaging (1 ultrasound), gastrinomas were found and removed in six patients (33%). Twenty-four gastrinomas were found in 20 patients at laparotomy: eight in lymph nodes around the pancreatic head, four in the pancreatic head, one in the pancreatic body, three in the pancreatic tail, three in the pyloric channel, one in the duodenal wall, two in the jejunum at the ligament of Treitz, one in the ovary, and multiple liver metastases in one patient. If one excludes patients with MEN-I or liver metastatic disease, 12/28 (43%) of patients were biochemically "cured" immediately after operation. This result decreased to 7/23 (30%) with greater than 6 months follow-up. No patients with gastrinomas resected have developed recurrent gastrinoma on follow-up imaging studies (longest follow-up: 4 years). This study indicates that 95% of metastatic gastrinoma can be diagnosed before operation and that, by a combination of careful imaging studies and thorough exploration at surgery, 30% of patients with gastrinomas may be curable.

Adult↗
PubMed1986

Everting (toposcopic) catheter for broad clinical application.

The advanced development of the clinical everting (toposcopic) catheter is described. A detailed discussion of the design and outline of the fabrication techniques are followed by a thorough performance evaluation and summary of the first two clinical applications. The everting element is a low-durometer thermoplastic polyurethane elastomer. Surface treatments include the bonding of a hydrophilic polymeric coating, optimized for lubricity, to the sliding internal surfaces of the catheter. Eversion pressures and infusion/aspiration flow rates have been measured under various conditions and the infusate-in-blood mixing potential investigated. A preliminary assessment is given of the clinical performance of the catheter in the vascular delivery of chemotherapy and standard endoscopic retrograde cholangiopancreatography.

Animals↗
PubMed1986

Adrenal masses differentiated by MR.

Magnetic resonance imaging was performed in 30 patients with adrenal masses. The abnormalities included adrenal adenomas (n = 10), carcinomas (n = 2), pheochromocytomas (n = 12), and adrenal metastases (n = 6). By the ratio of the signal intensity of the adrenal mass to that of the liver, adenomas could be distinguished from adrenal metastases, adrenal carcinomas, and pheochromocytomas. Metastases and pheochromocytomas could generally be differentiated.

Adenoma↗
PubMed1986

Glioblastoma: catheter techniques for isolated chemotherapy perfusion.

Techniques have been developed for isolated perfusion of chemotherapeutic agents in patients with glioblastoma. Three catheters that facilitate crossing the carotid siphon have been developed; two are based on an everting or toposcopic principle, and one uses microjets for deflectability and improved mixing. Blood from the ipsilateral jugular vein is aspirated at high volumes (300 ml/min) for extracorporeal circulation through an adsorption column (for recovery of carmustine) or dialysers (for recovery of cisplatin). Preliminary experience in 10 patients suggests that high doses of chemotherapeutic agent can be administered using these catheters, with reduced retinal and systemic toxicity.

Brain Neoplasms↗
PubMed1986

Spinal Wada test.

Various doses of pentobarbital (1.25-20 mg) and lidocaine (2.5-20 mg) were injected selectively into the artery of Adamkiewicz and anterior spinal artery of 11 monkeys. Pentobarbital produced an acute paraplegia; lidocaine caused a transient paraplegia followed by hyper-reflexia and muscular fasciculation. Duration of effect varied from 5 to 60 minutes with both drugs and was dose related. Effects were totally reversible. The use of intraarterially administered barbiturates and lidocaine may be more sensitive than angiography for predicting cord blood supply during arteriography for spinal arteriovenous malformations or embolization of critical vessels, such as the right bronchial artery.

Animals↗
PubMed1986

MRI of indeterminate adrenal masses.

The histologic type of adrenal tumors can be accurately predicted by MRI on the basis of their signal intensity on a T2-weighted image. However, a small but significant number of nonfunctioning adenomas, carcinomas, and metastases cannot be differentiated because they have similar signal intensities on a spin-echo 2500/80 scan. Eight (21%) of 38 of these tumors fell into this group. Differentiation between incidental adenomas and metastases can be conclusively achieved only when the primary neoplasm can also be imaged and displays high signal intensity on T2-weighted images.

Adenoma↗
PubMed1986

Rebound thymic hyperplasia after treatment of Cushing's syndrome.

Rebound thymic hyperplasia has been described in children and young adults after recovery from stress. Similar thymic enlargement has been observed in patients after remission of Cushing's syndrome. In one patient successfully treated for ectopic adrenocorticotropic hormone (ACTH) syndrome by resection of a bronchial carcinoid with a hilar metastasis, the postoperative enlarging mediastinal mass suggested recurrent tumor. In another patient treated for an undetected ectopic ACTH source by a cortisol antagonist, the enlarging thymus could be confused with a thymic carcinoid. The typical thymic appearance on CT and the chronologic relation to declining cortisol levels should prevent such diagnostic errors.

ACTH Syndrome, Ectopic↗
PubMed1986

Mixing studies during intracarotid artery infusions in an in vitro model.

Sporadic instances of retinal damage and of focal brain toxicity have been observed following intracarotid artery infusions of chemotherapeutic agents (such as BCNU and cis-platinum) for the treatment of glioblastomas. The episodic nature of these toxicities is consistent with the possibility that the drug solutions were streaming from the catheter tip and, therefore, were not well mixed or not uniformly distributed in all branches distal to the catheter tip location. To test this hypothesis, an in vitro system was fabricated which included a transparent model of the human carotid artery and its major branches. These were furnished with pulsatile flow of a blood simulant. Dye solutions infused at several infusion rates through various types of catheters in both supraophthalmic and infraophthalmic positions were monitored and recorded on videotape and photographic film. The effluent streams from distal branches of the model were collected, and the relative concentrations of dye in each branch were determined spectrophotometrically. The results indicate that infusate streaming occurs at low infusion rates. In some cases, the concentration in a given branch can be at least five times the expected concentration. Similar occurrences of streaming in vivo could cause focal toxicity. Methods to improve mixing should be used during intra-arterial administration of drugs; these include increasing the infusion rates and improving catheter tip design.

Antineoplastic Agents↗
PubMed1986

Drug streaming during intra-arterial chemotherapy.

Treatment of brain tumors by intra-arterial (IA) chemotherapy is occasionally complicated by sites of focal toxicity in the brain and retina. A possible cause of focal toxicity is non-uniform drug delivery due to intravascular drug streaming. To investigate this phenomenon in vivo, the authors examined the distribution of drug delivery after internal carotid artery (ICA) infusion in rhesus monkeys. Carbon-14 (14C)-labeled iodoantipyrine was delivered into the ICA of eight monkeys at slow infusion rates (1% to 2% of ICA flow) or at fast infusion rates (20% of ICA flow) combined with additional techniques to promote mixing with ICA blood. Two monkeys received intravenous (IV) 14C-antipyrine. Uniformity of delivery was assessed by comparing high-to-low ratios of isotope concentration in four brain regions evaluated by quantitative autoradiography. There was striking non-uniformity of drug delivery in the slow IA infusion group, with as much as 13-fold differences in drug concentration in anatomically contiguous areas. The values of high-to-low concentration ratios (mean +/- standard deviation) in individual autoradiographic planes were: 1) frontoparietal cortex: slow IA infusion 4.54 +/- 2.07, fast IA infusion 1.71 +/- 0.31, IV infusion 1.30 +/- 0.174; 2) frontoparietal white matter: slow IA infusion 2.94 +/- 1.45, fast IA infusion 1.59 +/- 0.41, IV infusion 1.34 +/- 0.21; 3) temporal cortex: slow IA infusion 5.43 +/- 3.57, fast IA infusion 1.69 +/- 0.24, IV infusion 1.67 +/- 0.25; 4) basal ganglia: slow IA infusion 3.6 +/- 2.9, fast IA infusion 1.18 +/- 0.10, IV infusion 1.09 +/- 0.04. Differences between concentration ratios after slow IA and fast IA infusion are significant (p less than 0.01); those between fast IA and IV infusion are not significant. Intra-arterial drug administration at infusion rates analogous to those currently used clinically results in drug streaming with markedly heterogeneous drug deposition in the perfused hemisphere. This may cause suboptimal drug levels in the tumor, and toxic levels at sites within the perfused hemisphere. This effect can be abrogated by techniques that eliminate drug streaming.

Animals↗
PubMed1986

Selective venous sampling for gastrin to localize gastrinomas. A prospective assessment.

In 27 consecutive patients with Zollinger-Ellison syndrome, we prospectively evaluated the ability of selective venous sampling for gastrin to localize gastrinomas, then compared the results with those from imaging studies and with findings at surgery. All patients had a gastrin gradient, but in only 20 patients was it significant. Neither the magnitude of the gastrin gradient nor its presence or absence correlated with the frequency with which gastrinoma was found at surgery. A gastrinoma was found at surgery in 15 patients, of whom 12 had positive imaging studies, 11 had a significant gastrin gradient, 14 had both tests positive, and 1 had both tests negative. A gastrinoma was not found at surgery in 12 patients, of whom 8 had a significant gradient and none had a positive imaging study. Gastrin sampling has equal sensitivity with imaging studies in localizing gastrinoma, but imaging studies have higher positive and negative predictive values and higher specificity. Thus, selective venous sampling for gastrin is much less useful in localizing gastrinoma than has been suggested and should not be routinely done preoperatively in patients with Zollinger-Ellison syndrome.

Adult↗
PubMed1986

The spectrum of sonographic findings in pancreatic carcinoma.

The ultrasound studies of 59 patients with cancer of the pancreas were reviewed and the findings grouped into two categories: intrapancreatic, which included the appearance of the primary tumor and the pancreatic duct; and extrapancreatic, which included biliary obstruction, hepatic metastases, regional lymph node involvement, ascites, spleen enlargement and invasion, and alteration of the upper abdominal veins. Pancreatic duct dilatation was more evident with smaller tumors of the pancreatic head, while inferior vena cava compression was found not to be a constant finding even with large tumors of the head of the pancreas. Tumor extension to regional lymph nodes was difficult to detect and consequently underestimated. Nonvisualization, occlusion with or without collaterals, and displacement or deformity of the major branches of the portal venous system were detectable sonographically. The liver metastases of pancreatic carcinoma tended to be small and hypoechoic. This is a different pattern from that typically described for other gastrointestinal adenocarcinomas and, in particular, markedly different and distinguishable from the metastatic pattern seen with malignant pancreatic islet cell tumors. The significance of the intra- and extrapancreatic changes seen sonographically in cancer of the pancreas by ultrasound is discussed in relationship to clinical staging and prognosis.

Adenocarcinoma↗
PubMed1986

Magnetic resonance imaging of the adrenal.

Magnetic resonance imaging (MRI) of the adrenals was performed on 50 subjects: 5 normal volunteers, 6 Cushing patients with bilateral adrenal hyperplasia, 14 patients with adrenal adenomas, 3 with adrenal carcinomas, 15 with pheochromocytomas and 7 with metastatic disease to the adrenal. The normal and hyperplastic adrenal glands were imaged in all cases. Using the signal intensity of the adrenals on a T2 weighted image, various forms of adrenal pathology could be differentiated. A ratio of signal intensity of the adrenal mass to the liver was utilized and allowed the differentiation of adrenal adenomas from adrenal carcinomas, pheochromocytomas and metastases. Using the same ratio, metastases could be distinguished from pheochromocytomas as well. MRI appears to be particularly valuable in distinguishing clinically silent adrenal metastases from nonfunctioning adrenal adenomas.

Adenoma↗
PubMed1985

Absolute ethanol injection of the adrenal artery: hypertensive reaction.

Transcatheter injection of 0.4 ml of absolute ethanol into the adrenal artery was performed in three Rhesus monkeys. The injection produced a mean increase of 60 mmHg in systolic blood pressure and 50 mmHg in diastolic blood pressure within two minutes. Hypertension was accompanied by cardiac arrhythmias (two monkeys) and sinus tachycardia (one monkey). These changes were probably related to an acute catecholamine release. Embolization of the inferior phrenic artery with Gelfoam powder produced only a mild blood pressure elevation in three monkeys (6 mmHg systolic pressure and 10 mmHg diastolic pressure).

Adrenal Glands↗
PubMed1985

Origin of spinal arteriovenous malformation and normal cord vasculature from a common segmental artery: angiographic and therapeutic considerations.

The dural type of spinal arteriovenous malformation (AVM) can be cured by excision or by embolization of the nidus. The common origin of the blood supply to the malformation and to the cord from the same segmental artery would profoundly affect therapeutic choices. This anatomic situation was encountered in two of nine such lesions. The angiographic appearance and the importance of recognizing this common origin is discussed.

Adult↗
PubMed1985

Basilar venous plexus of the posterior fossa: a potential source of error in petrosal sinus sampling.

Sampling of serum from the inferior petrosal sinus can provide important information about the source of elevated adrenocorticotropic hormone (ACTH) levels. This often leads to improved results of pituitary surgery for Cushing disease. The authors describe a successful catheterization technique and illustrate the venous anatomy of the inferior petrosal sinuses and basilar plexus.

Adenoma↗