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Biomedical subjects

H R Alexander

Publications and source records attributed to H R Alexander.

At least 91 records · Page 5Linked to original sources
PubMed1996

Parathyroid adenomas in the aortopulmonary window.

PURPOSE: To describe localization studies in nine patients with ectopic parathyroid adenomas in the aortopulmonary window. MATERIALS AND METHODS: Nine patients with ectopic parathyroid tissue (eight adenomas, one hyperplastic gland) in the aortopulmonary window were examined with ultrasound (US), computed tomography (CT), magnetic resonance (MR) imaging, and scintigraphy. Diagnostic arteriography (n = 4) and venous sampling (n = 3) were performed in the first four patients; arteriography for the purpose of staining was attempted in the last five patients. RESULTS: The results of CT and MR imaging studies were positive in eight of nine patients (89%) and five of eight patients (63%), respectively. The results of thallium/technetium scintigraphy were negative in three patients scanned (0%), but the results of a repeat study in one patient were positive (33%). Sestamibi scans were positive in six of six patients (100%). Single photon emission CT was performed in all six patients and enabled distinction between adenomas in the aortopulmonary window and those in the thymus. CONCLUSION: Ectopic parathyroid glands in the aortopulmonary window are usually detected at sestamibi scintigraphy, and SPECT is helpful in distinguishing these adenomas from more common adenomas in the anterior mediastinum. CT and MR imaging studies can also enable this distinction, but imaging must extend below the aortic arch.

Adenoma↗
PubMed1996

Treatment of patients with melanoma of the extremity using hyperthermic isolated limb perfusion with melphalan, tumor necrosis factor, and interferon gamma: results of a tumor necrosis factor dose-escalation study.

PURPOSE: To evaluate response rates and systemic and regional toxicity of hyperthermic isolated limb perfusion (ILP) for treatment of in-transit metastases of extremity melanoma using escalating-dose tumor necrosis factor (TNF) in conjunction with melphalan and interferon gamma (IFN). PATIENTS AND METHODS: All patients received IFN 0.2 mg2 for 2 days followed by a 90-minute ILP with TNF and IFN (0.2 mg) given at time 0 and melphalan (10 mg/L limb volume) given at 30 minutes. Twenty-six patients were treated with 4 mg of TNF and 12 patients received 6 mg of TNF. All patients had assessable disease in the perfusion field and all but two patients were assessable for response at 1 month after treatment. RESULTS: Mean peak perfusate TNF levels in the 4-mg group were 4.8 micrograms/mL, compared with 7.4 micrograms/mL for the 6-mg group (P = .03). The complete response rate in the 4-mg TNF group was 76%, with an overall objective response rate of 92%, compared with 36% and 100% for the 6-mg group. Subgroup analyses showed that the lower complete response rate in the 6-mg TNF group was not explained by differences in disease burden or prior regional therapy. Systemic drug toxicity was short-lived, easily managed, and related to perfusate leak more than to TNF perfusate dose. Regional toxicity, particularly painful myopathy and neuropathy, was greater with the 6-mg dose level and was considered dose-limiting. CONCLUSION: ILP with 4 mg TNF, IFN, and melphalan can lead to complete local responses in the majority of patients with extremity melanoma. Escalating the TNF dose to 6 mg did not increase the complete response rate and increased regional toxicity.

Adult↗
PubMed1996

False-positive iodine-131 whole-body scans due to cholecystitis and sebaceous cyst.

False-positive whole-body 131I scans are not frequent but have serious consequences in the management of patients with thyroid cancer. They can be classified in four main groups: elimination of iodine in body fluids, infection or inflammation, cysts or transudates and nonthyroid tumors. We report on two patients with false-positive post-therapy 131I scans. The first patient had uptake projected in the right pelvic area which was later proven to be a large gluteal sebaceous cyst. The second patient had uptake in the gallbladder area that did not disappear after 131I treatment; she underwent exploratory laparotomy which revealed extensive chronic cholecystitis. These cases illustrate two new causes of false-positive 131I whole-body scans (sebaceous cyst and cholecystitis), which highlights two mechanisms (elimination in body fluid and inflammation).

Adenocarcinoma, Follicular↗
PubMed1995

Endogenous D-factor activity partially mediates the toxic but not the therapeutic effects of tumor necrosis factor.

We have earlier shown that passive immunization against differentiation-inducing factor/leukemia-inhibitory factor (D factor) activity improves the survival of endotoxemic mice, suggesting that D factor may contribute to the systemic toxicity associated with tumor necrosis factor (TNF). In the current experiments, TNF induced D-factor gene expression in various tissues of non-tumor-bearing female C57BI/6 mice. Passive immunization against D-factor significantly improved survival after a lethal TNF challenge in both non-tumor-bearing (p2 < 0.02) and tumor-bearing mice (p2 < 0.01). In mice bearing 10-day s.c. MCA 105 sarcomas, D-factor antibody alone had no effect on tumor growth as compared with control IgG. Tumor regression and regrowth in mice treated i.v. with TNF was not affected by pre-treatment with D-factor antibody, as compared with pre-treatment with IgG. However, TNF-treatment-related mortality was abrogated by pre-treatment with D-factor antibody (0% vs. 36% for IgG-pre-treated controls). These results indicate that endogenous D-factor activity contributes to the toxicity but not to the anti-tumor effects of TNF therapy. With renewed interest in the use of TNF for the treatment of patients with cancer, improved understanding of the role of D factor in mediating the effects of TNF may have important clinical benefits.

Animals↗
PubMed1995

Reductions in tissue plasminogen activator and thrombomodulin in blood draining veins damaged by venous access devices.

A frequent complication of venous access devices (VADs) is axillary-subclavian venous thrombosis. To study this problem we have compared blood drawn through VADs with peripheral blood samples in a group of oncology patients with venographically demonstrated venous damage (N = 14) and a group with normal venograms (N = 21). The samples were assayed for a battery of proteins believed to be involved in thrombogenesis. After approximately six weeks of catheterization the venographically abnormal patients had significantly less thrombomodulin (P = 0.0055) and significantly higher PAI:tPA (P = 0.022) in catheter-drawn samples as compared with the venographically normal group. Although the data are inconclusive, it is hypothesized that these changes resulted from local endothelial injury.

Adult↗
PubMed1995

Localization of insulinomas to regions of the pancreas by intra-arterial stimulation with calcium.

OBJECTIVE: To determine the sensitivity of calcium injected into pancreatic arteries in localizing insulin-secreting tumors to regions of the pancreas. DESIGN AND PATIENTS: To stimulate the release of insulin, 25 patients with surgically proven insulinomas (average diameter, 15 mm) had calcium gluconate (0.025 mEq Ca++/kg body weight) injected before surgery into the arteries supplying the pancreatic head (gastroduodenal and superior mesenteric arteries) and the body and tail (splenic artery) of the pancreas. SETTING: Tertiary referral hospital. MEASUREMENTS: Insulin levels were measured in samples taken from the right and left hepatic veins before and 30, 60, and 120 seconds after calcium injection. A twofold increase in insulin level in the sample taken from the right hepatic vein 30 or 60 seconds after injection localized the insulinoma to the segment of the pancreas supplied by the selectively injected artery. Localization done using calcium stimulation was compared with localization done using transcutaneous ultrasonography (n = 22), computed tomography (n = 23), magnetic resonance imaging (n = 21), arteriography (n = 25), and portal venous sampling (n = 9). RESULTS: Calcium stimulation localized 22 of 25 insulinomas (sensitivity, 88% [95% CI, 68% to 97%]) to the correct region of the pancreas. The sensitivities of the other imaging methods were 9% for ultrasonography (CI, 1% to 23%), 17% for computed tomography (CI, 5% to 39%), 43% for magnetic resonance imaging (CI, 22% to 66%), 36% for arteriography (CI, 18% to 57%), and 67% for portal venous sampling (CI, 30% to 93%). Calcium stimulation added only a few minutes to the time needed for pancreatic arteriography and caused no morbid conditions. CONCLUSION: Intra-arterial calcium stimulation with right hepatic vein sampling for insulin gradients is the most sensitive preoperative test for localizing insulinomas.

Adult↗
PubMed1995

Potential involvement of IL-10 in suppressing tumor-associated macrophages. Colon-26-derived prostaglandin E2 inhibits TNF-alpha release via a mechanism involving IL-10.

The administration of murine TNF-alpha to colon (C)-26 bearing mice, significantly protects the host against the catabolic effects of the tumor. This effect of exogenous TNF-alpha can be primarily attributed to tumor lysis rather than to a direct anticachectic action. Murine peritoneal macrophages cultured with the C-26 line or with C-26 culture supernatant do not release TNF-alpha in response to LPS stimulation. The reduction in TNF-alpha levels is associated with a significant increase in IL-10 levels. Single cell suspension of freshly disaggregated C-26 tumor (which contains host macrophages), do not produce TNF-alpha but contain significant levels of PGE2 and IL-10. In contrast, PGE2 but not TNF-alpha or IL-10 can be detected in the C-26.IVX cell line that is used to generate tumors in vivo. Neutralizing anti IL-10 Ab but not isotype-matched Ab, significantly reverses the inhibitory effect of the tumor cells and their culture supernatant on macrophage TNF-alpha release. Additional evidence is presented to indicate that the C-26-derived inhibitory activity is related to PGE2. Taken together, these results support the hypothesis that tumor-derived PGE2 prevents tumor-infiltrating macrophages from producing TNF-alpha, in part by augmenting macrophage IL-10 synthesis.

Animals↗
PubMed1995

Continuous intraoperative external monitoring of perfusate leak using iodine-131 human serum albumin during isolated perfusion of the liver and limbs.

Regional isolated perfusion using tumor necrosis factor (TNF) shows significant promise for treatment of cancer which is limited to limbs or organs. The high toxicity of TNF requires very sensitive real time monitoring of leakage in order to avoid serious patient complications. Human serum albumin labeled with iodine-131 is used with an externally mounted and collimated NaI(Tl) detector to track the leakage of blood from the isolated perfusion blood circuit into the general systemic vascular space. Blood activity levels measured using the monitor demonstrated a very good correlation with blood serum samples taken concurrently with external monitoring. External monitoring can reduce the risks of perfusion leakage intraoperatively with the precision necessary to safely perform isolated perfusion using TNF.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1995

Venographic surveillance of tunneled venous access devices in adult oncology patients.

BACKGROUND: Tunneled venous access devices (VADs) are often essential in the care of patients with advanced malignancies, but they carry an uncertain risk of thrombosis. METHODS: To determine the incidence of venoocclusion related to silicone VADs in a population of adult oncology patients, we prospectively studied 50 individuals with upper extremity venograms approximately 6 weeks after their VADs had been implanted. Twenty-one of these patients were reevaluated with venograms approximately 12 weeks after catheterization. In addition, venograms were performed on a separate group of 24 patients who needed catheterization of axillary-subclavian veins that had been catheterized in the past. RESULTS: The 6-week venograms in the prospective study showed partial venous obstruction in 15 patients (30%), whereas three (6%) had developed symptomatic total venoocclusion by this time. The 12-week venograms showed two additional complete occlusions. Venograms of 30 previously catheterized veins showed complete venoocclusion in nine (30%), although only two had a history of thrombosis. CONCLUSIONS: Our observations indicate that VADs frequently cause partial venoocclusion within the first 6 weeks of catheterization and that permanent venous damage from VADs is common, even without a history of VAD-related thrombosis.

Adult↗
PubMed1995

Cachexia-anorexia-asthenia.

The National Cancer Institute (Canada) sponsored a workshop on symptom control in Banff, Alberta, in October 1993. This article reports on the workshop recommendations for research on one symptom complex, the cachexia-anorexia-asthenia syndrome. In addition to encouraging study generation, the recommendations provide a baseline for assessing the scope and strength of future Canadian research initiatives on cachexia-anorexia-asthenia.

Anorexia↗
PubMed1995

Prospective study of surgical resection of duodenal and pancreatic gastrinomas in multiple endocrine neoplasia type 1.

BACKGROUND: The role of surgical resection of gastrinoma in multiple endocrine neoplasia type 1 (MEN 1) is controversial because of low biochemical cure rates, but with adequate duodenal exploration higher cure rates may be possible. METHODS: We have prospectively evaluated this proposal in ten consecutive patients with MEN 1 and Zollinger-Ellison syndrome who underwent surgical exploration for gastrinoma resection including a detailed evaluation of the duodenum by palpation, intraoperative endoscopy with transillumination, and duodenotomy. RESULTS: Duodenal tumors were present in seven patients. Six of seven patients had metastatic deposits in lymph nodes, and two of seven had synchronous pancreatic tumors. Three patients had a single duodenal tumor, one patient had two tumors, and three patients had more than 20 duodenal tumors. Positive gastrin staining by use of immunohistochemistry was seen in all duodenal tumors. None of these seven patients were biochemically cured. Of three patients with negative duodenal explorations, two had single pancreatic tumors removed and one had only lymph node gastrinoma. No patients were biochemically cured. CONCLUSIONS: Not all patients with MEN 1 and Zollinger-Ellison syndrome have duodenal gastrinomas. In the 70% of patients with duodenal tumors, even extensive duodenal exploration with removal of positive lymph nodes does not result in cures because 86% of tumors had metastasized to lymph nodes and 43% of patients had large numbers of tumors.

Adult↗
PubMed1995

Role of preoperative iodocholesterol scintiscanning in patients undergoing adrenalectomy for Cushing's syndrome.

BACKGROUND: Iodocholesterol scintiscanning (IS) is a noninvasive, functional diagnostic test. We report our experience with IS as an adjunct for adrenal surgery for Cushing's syndrome. METHODS: Between April 1983 and October 1994, 23 patients with Cushing's syndrome from benign primary adrenal disease underwent IS and computed tomography (CT) and/or magnetic resonance imaging (MRI). Twelve patients had unilateral adrenal involvement with a solitary adenoma (n = 11) or unilateral multinodular disease (n = 1), and 11 patients had bilateral adrenal disease. RESULTS: In patients with Cushing's syndrome caused by unilateral adrenal disease, IS was 100% specific and 100% sensitive, whereas in two cases CT/MRI incorrectly showed bilateral disease. In patients with Cushing's syndrome with bilateral adrenal involvement, IS had one false-negative result with nonvisualization. CT/MRI showed unilateral disease in four cases and no abnormalities in two. All patients in this series were cured of Cushing's syndrome after unilateral adrenalectomy in 11 cases and bilateral adrenalectomy in 12 cases. CONCLUSIONS: IS is a highly sensitive and specific imaging modality and is an essential adjunct to biochemical testing in planning adrenal resections for Cushing's syndrome caused by primary adrenal disease.

Adenoma↗
PubMed1995

Role of surgery in management of adrenocorticotropic hormone-producing islet cell tumors of the pancreas.

BACKGROUND: Ectopic adrenocorticotropic hormone-producing islet cell tumors of the pancreas (ACTH-ICT) are a rare cause of Cushing's syndrome with a severe and rapidly progressive clinical course. METHODS: Charts were reviewed on all patients evaluated and treated for proven Cushing's syndrome caused by ACTH-ICT (n = 12), specifically for the role of surgery in the management of this disease. RESULTS: Ten (83%) of twelve patients with ACTH-ICT had liver metastases at the time of diagnosis (eight of eight with Zollinger-Ellison syndrome, two of four without Zollinger-Ellison syndrome). Surgical management of the primary tumor included three patients who underwent distal pancreatectomy combined with hepatic resection and one patient who underwent laparoscopic enucleation of a tumor from the pancreatic tail. Eight of twelve patients underwent bilateral adrenalectomy to control symptoms of Cushing's syndrome, including three patients who underwent concurrent distal pancreatectomy and hepatic resection. Six of twelve patients died of the disease within 2 1/2 years of diagnosis, four are alive with progressive hepatic metastases, and one has biochemical evidence of disease. CONCLUSIONS: ACTH-ICT of the pancreas is an aggressive tumor, particularly when there is coproduction of gastrin. The benefit of aggressive surgical resection of primary or metastatic ACTH-ICT has not been established. However, palliative bilateral adrenalectomy is justified, because no patients had biochemical cures after aggressive surgical resection in this series.

ACTH Syndrome, Ectopic↗
PubMed1995

Hemipelvectomy for soft tissue sarcoma: clinical results in fifty-three patients.

The management of high-grade extremity sarcomas typically combines local surgical excision with some form of adjuvant therapy. However, some patients with large proximal lesions present with no local resection options, and high radical amputation is often the only way to accomplish complete tumour excision. A retrospective review was made of the clinical courses of 53 patients with high-grade sarcomas of the lower extremity who underwent hemipelvectomy with curative intent at the National Institutes of Health between 1975 and 1989. Hemipelvectomy provided excellent local control, with no local recurrences. Although 60% of the patients experienced post-operative complications, the operative mortality was zero. Ten years after hemipelvectomy, the actuarial disease-free rate was 25% and the survival rate was 35%. There were no statistically significant survival differences when patients were stratified according to tumour size, perioperative blood transfusion requirements or the use of adjuvant chemotherapy. We conclude that hemipelvectomy provides excellent local control and a reasonable cure rate for patients with locally unresectable soft tissue sarcomas of the lower extremity.

Actuarial Analysis↗
PubMed1995

Cytokine levels and systemic toxicity in patients undergoing isolated limb perfusion with high-dose tumor necrosis factor, interferon gamma, and melphalan.

PURPOSE: Isolated limb perfusion (ILP) with tumor necrosis factor (TNF), interferon gamma, and melphalan (M) has been reported to result in high response rates for extremity melanoma and sarcoma. We have evaluated the relationship of systemic TNF exposure to induction of several secondary mediators and incidence of systemic toxicity. PATIENTS AND METHODS: Nineteen patients with extremity melanoma (n = 16) or sarcoma (n = 3), underwent 90-minute ILP with TNF-alpha, interferon gamma (0.2 mg), and M (10 to 13 mg/L of limb volume) (TNF/IFN/M) (n = 12), or M alone (n = 7). Continuous intraoperative monitoring (CIM) for systemic leak from the perfusion circuit was performed using radioactive iodine-131 albumin. Cytokine levels in the perfusate and systemic circulation during and after ILP were measured by enzyme-linked immunosorbent assay. RESULTS: Systemic leaks > or = 1% from the perfusion circuit occurred in six patients who received TNF/IFN/M and in four who received M alone. Hypotension that required vasopressor support occurred in six of six patients with evidence of a leak (> or = 1%) and zero of six patients without a leak (< 1%). These six patients had significantly higher peak systemic TNF levels during and after perfusion than patients without a leak (2.8 and 8.2 ng/mL v 0.7 and 2.0 ng/mL, respectively; P < .05). All patients who received TNF/IFN/M had significantly greater increases in systemic interleukin-6 (IL-6) levels than in patients with M alone (12,395 +/- 10,374 pg/mL v 79.4 +/- 7.2 pg/mL, respectively; P < .001). Intracellular adhesion molecule (ICAM), IL-8, and TNF-R levels were also increased after ILP with TNF/IFN/M. CONCLUSION: ILP with TNF/IFN/M can be safely performed, as I131 albumin provides a sensitive measure of systemic leakage from the perfusion circuit. Patients with a measured leak of > or = 1% develop mild and transient postoperative hypotension with significantly higher systemic TNF levels and lower perfusate TNF levels than in patients without leaks.

Adult↗
PubMed1995

High cervical intravagal hypercellular parathyroid gland as the etiology of severe persistent primary hyperparathyroidism.

The preoperative localization and operative management of a high cervical intravagal parathyroid adenoma in a young woman with severe persistent primary hyperparathyroidism is presented. The etiology of persistent hyperparathyroidism is most frequently a missed adenoma that is often in an ectopic location; of these, undescended adenomas represent a small but important proportion. If clinical suspicion and preoperative localization procedures suggest an undescended gland, a direct surgical approach using a high cervical incision and a unilateral exploration is often successful.

Adenoma↗