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Steven K Libutti

Publications and source records attributed to Steven K Libutti.

70 records · Page 4Linked to original sources
PubMed2002

Utility of rapid intraoperative parathyroid hormone assay to predict severe postoperative hypocalcemia after reoperation for hyperparathyroidism.

BACKGROUND: Patients undergoing reoperative parathyroidectomy may develop severe transient or permanent hypoparathyroidism. This study's purpose was to determine the utility of intraoperative parathyroid hormone (IO-PTH) values in predicting the development of severe hypocalcemia for patients undergoing reoperation for primary hyperparathyroidism. METHODS: Between March 1999 and October 2001, 68 patients with persistent or recurrent hyperparathyroidism underwent reoperation using IO-PTH measurements. The maximum percent decrease and lowest actual PTH value obtained at surgery were compared to determine any correlation with the development of postoperative hypocalcemia requiring supplementation. RESULTS: Of 68 patients, 25 required calcium and calcitriol postoperatively and 43 did not. There was a significant difference between the 2 groups with respect to lowest IO-PTH value (18.4 +/- 2.6 vs 28.0 +/- 3.9 pg/mL; P =.02), percent decrease in IO-PTH (89% +/- 1% vs 80% +/- 3%; P =.03), and lowest postoperative ionized calcium (1.06 +/- 0.01 vs 1.19 +/- 0.01 mmol/L; P <.001). A percent decrease in IO-PTH of 84% or greater was found to be predictive of patients experiencing hypocalcemia requiring supplementation with a positive predictive value of 46% and a negative predictive value of 82%. CONCLUSIONS: Although a maximum percent decrease in IO-PTH of 84% or greater was associated with an increased incidence of postoperative hypocalcemia requiring supplementation in the 68-patient cohort, on further analysis the association was significant only for patients with multiglandular disease and not those with single adenomas. This value may be useful for identifying patients who will need closer postoperative monitoring or prophylactic supplementation.

Adult↗
PubMed2002

Juxtathyroidal neck soft tissue angiosarcoma presenting as an undifferentiated thyroid carcinoma.

Angiosarcoma is a malignant growth of endothelial origin, uncommon in the head and neck. We present the case of a 38-year-old woman with long-standing goiter who presented with a rapidly growing 6.0-cm neck mass. Fine-needle aspiration biopsy of the tumor showed features of "undifferentiated thyroid carcinoma (ThyrCa)." Total thyroidectomy resulted in extirpation of all gross disease. Pathology revealed a high-grade angiosarcoma of the neck invading the thyroid gland, coexisting with papillary ThyrCa (follicular variant) in the contralateral lobe. Aggressive external electron beam radiotherapy was initiated for local control. Despite the absence of systemic dissemination initially, bulky neck recurrences, and pulmonary metastases developed rapidly, leading to the patient's demise on postoperative day 41. Autopsy showed metastatic disease involving most organs. This case illustrates that neck angiosarcomas need to be considered in the differential diagnosis of "poorly differentiated" thyroid malignancies. These soft tissue neck tumors may complicate postoperative management due to their bleeding tendency and aggressive infiltrative behavior, and carry a dismal prognosis because of the rapidity of development of local recurrence and distant metastases.

Adult↗
PubMed2002

Neuroendocrine tumors of the pancreas in von Hippel-Lindau disease: spectrum of appearances at CT and MR imaging with histopathologic comparison.

PURPOSE: To demonstrate the imaging characteristics of neuroendocrine tumors (NETs) of the pancreas in patients with von Hippel-Lindau (VHL) disease to establish diagnostic criteria. MATERIALS AND METHODS: Twenty-five patients with VHL disease and 29 surgically confirmed pancreatic NETs were included. Screening computed tomographic (CT) and/or magnetic resonance (MR) imaging findings were reviewed, and tumor number, diameter, growth rates (doubling time), location, presence of metastatic disease, and attenuation or enhancement properties were determined. RESULTS: Eighteen of 29 (62%) pancreatic NETs were smaller than 3.0 cm in diameter and enhanced homogeneously on contrast material-enhanced CT and MR images. No tumor smaller than 3.0 cm metastasized. Tumors 3.0 cm or larger (11 [38%] of 29) more often enhanced heterogeneously, and two of 11 were associated with hepatic metastases. Smaller (<3.0 cm) tumors displayed longer mean doubling times (mean, 927 vs 351 days) than did larger (> or =3.0 cm) tumors; however, there was considerable overlap. Fifteen (52%) tumors were located in the pancreatic head; eight (28%), in the tail; and six (21%), in the body. Ten (40%) patients with pancreatic NETs had associated pheochromocytomas, and 22 (88%) had no or mild pancreatic cystic disease, which is substantially more than the general population of patients with VHL disease. CONCLUSION: Pancreatic NETs in VHL have characteristic features at CT and MR imaging: Most are small, located in the pancreatic head, and enhance homogeneously. Tumors larger than 3.0 cm are prone to metastasize and enhance heterogeneously.

Adult↗
PubMed2002

Microarray gene expression analysis of murine tumor heterogeneity defined by dynamic contrast-enhanced MRI.

Current methods of studying angiogenesis are limited in their ability to serially evaluate in vivo function throughout a target tissue. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and pharmacokinetic modeling provide a useful method for evaluating tissue vasculature based on contrast accumulation and washout. While it is often assumed that areas of high contrast enhancement and washout comprise areas of increased angiogenesis and tumor activity, the actual molecular pathways that are active in such areas are poorly understood. Using DCE-MRI in a murine subcutaneous tumor model, we were able to perform pharmacokinetic functional analysis of a tumor, coregistration of MRI images with histological cross-sections, immunohistochemistry, laser capture microdissection, and genetic profiling of tumor heterogeneity based on pharmacokinetic parameters. Using imaging as a template for biologic investigation, we have not found evidence of increased expression of proangiogenic modulators at the transcriptional level in either distinct pharmacokinetic region. Furthermore, these regions show no difference on histology and CD31 immunohistochemistry. However, the expression of ribosomal proteins was greatly increased in high enhancement and washout regions, implying increased protein translation and consequent increased cellular activity. Together, these findings point to the potential importance of posttranscriptional regulation in angiogenesis and the need for the development of angiogenesis-specific contrast agents to evaluate in vivo angiogenesis at a molecular level.

Animals↗
PubMed2002

Rapid measurement of insulin using the Abbott IMx: application to the management of insulinoma.

BACKGROUND: Patients with multiple endocrine neoplasia (type 1) often present with multiple pancreatic endocrine tumours, such as insulinomas. A major difficulty in the surgical treatment of such patients is identifying which tumours are functionally active and therefore need to be resected for a cure. The objective of this study was to develop a rapid insulin assay that could be used intraoperatively for identifying insulinomas from pancreatic aspirates. METHODS: By reducing the incubation time and by increasing the sample volume, a rapid insulin assay was developed on the IMx analyser. This was used to measure insulin from tissue aspirates collected from suspected insulinomas under ultrasound guidance. RESULTS: The rapid insulin assay (y) could be performed in 14 min and showed a good correlation with the standard IMx (x) insulin assay (y = 0.808x + 0.04; r(2) = 0.986). Using the rapid insulin assay on pancreatic tissue aspirates, insulinomas could be readily distinguished from normal pancreatic tissue or from non-functional adenomas based on a marked increase in insulin content. CONCLUSION: In summary, a new rapid assay for insulin is described that compares favourably to the standard IMx insulin assay and can potentially be used intraoperatively on pancreatic aspirates for identifying functionally active insulinomas.

Adult↗
PubMed2002

Microarray technology and gene expression analysis for the study of angiogenesis.

Angiogenesis plays a major role in multiple disease processes including cancer, and new agents that modulate angiogenesis are rapidly entering clinical trials. The understanding of the biological mechanisms and downstream effects for many of these agents is poorly understood. It is therefore important that methods evolve to understand how an agent regulates angiogenesis, in order to promote a higher percentage of successful drug candidates. With the emergence of microarray technology for the evaluation of gene expression, researchers have a powerful tool for dissecting the biological mechanisms of angiogenesis. However, huge data sets and complex statistics pose a hurdle for the investigator to obtain useful and meaningful data. To eliminate problems in data analysis, proper design and planning prior to performing a microarray experiment is crucial to making valid conclusions. This review will discuss the critical factors in designing, performing and analysing microarray experiments, and the utility of various models of angiogenesis for microarray analysis.

Animals↗
PubMed2002

Intentional resection of the diaphragm during cytoreductive laparoscopic radical nephrectomy.

PURPOSE: Laparoscopic radical nephrectomy is being performed more commonly. To our knowledge intentional resection of the diaphragm during laparoscopic radical nephrectomy for large renal tumors has not yet been described. We detail the laparoscopic management of diaphragmatic resection. MATERIALS AND METHODS: From March 1996 to February 2001, 36 patients underwent cytoreductive laparoscopic radical nephrectomy at our institution in preparation for systemic immunotherapy. Charts and operative tapes were reviewed and cases were identified in which diaphragmatic resection was performed for locally invasive tumors. RESULTS: In 3 patients a portion of the diaphragm was dissected via laparoscopy during debulking nephrectomy. All patients had renal cell carcinoma with documented metastatic disease. The diaphragm was repaired laparoscopically using intracorporeal suturing techniques in 2 of the 3 patients and a chest tube was placed in all 3. Transient systolic hypotension and hypercarbia in 1 case resolved with manual ventilation. The chest tube was removed on postoperative days 2 to 4. There were no complications and no ipsilateral pleural metastasis was identified at an average of 6 weeks (range 2 to 23) of followup. CONCLUSIONS: A portion of the diaphragm may be intentionally resected during laparoscopic radical nephrectomy. This maneuver may be successfully managed without conversion to an open procedure. In cases of a large diaphragmatic defect or the potential for coagulopathy postoperatively a chest tube should be inserted. Potential invasion of the diaphragm by large tumors should not be considered a contraindication to cytoreductive laparoscopic radical nephrectomy.

Adult↗
PubMed2002

Hyperparathyroidism in hereditary syndromes: special expressions and special managements.

Hyperparathyroidism (HPT) in its hereditary variants assumes special forms, has special associations, and requires special managements. Familial hypocalciuric hypercalcemia (FHH or FBHH) and neonatal severe primary hyperparathyroidism (NSHPT) reflect heterozygous or homozygous mutations, respectively, in the calcium-sensing receptor. FHH and NSHPT represent the mildest and severest variants of HPT. Both cause hypercalcemia from birth and atypical HPT that always and uniquely persists after subtotal parathyroidectomy. Their HPT is likely polyclonal and nonneoplastic. In contrast, mono- or oligo-clonal parathyroid neoplasia underlays most other HPT variants: multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2A (MEN2A), and hyperparathyroidism-jaw tumor syndrome (HPT-JT). Familial-isolated HPT combines several diagnoses, including occult forms of the above syndromes. Each neoplastic variant has tumors in multiple parathyroids and a delayed, but still early age of onset for HPT (average age, 25-35 years). Each justifies special and similar approaches to parathyroidectomy: typically, identification of four glands, subtotal parathyroidectomy, rapid intraoperative parathyroid hormone (PTH) assays, and parathyroid cryopreservation. Outcomes of parathyroidectomy remain suboptimal in each. Each syndrome of parathyroid neoplasia associates with characteristic cancer(s): enteropancreatic neuroendocrine or foregut carcinoid tissues (MEN1), thyroidal C cells (MEN2A), or parathyroid (HPT-JT). HPT has promoted gene discovery more through its rare hereditary variants than through common adenoma; the main genes causing four of six hereditary variants are known. The RET mutation test became essential in management of MEN2A. The MEN1 test is less urgent, because it rarely guides a major patient benefit. The CASR test, perhaps least urgent, has largely been unavailable. Further progress in molecular genetics will enhance understandings, diagnosis, and therapy of HPT.

Calcium↗
PubMedDate not supplied

Intermittent hepatic vein balloon occlusion during radiofrequency ablation in the liver.

The purpose of the study was to assess the feasibility of intermittent hepatic vein balloon occlusion during percutaneous radiofrequency (RF) ablation. Eight non-anticoagulated patients who had primary (n = 2) and metastatic (n = 6) liver tumors with a mean diameter of 4.2 cm (range 2.4-6.5 cm) were treated, resulting in a mean ablation diameter of 6.3 cm (range 4.3-9.3 cm). Six of 9 (67%) of the balloon-occluded hepatic veins were patent. No clinical sequelae of thrombosis were noted. Mean length of follow-up with CT and/or MRI was 12 months. Local tumor control was achieved in 5 of 8 patients. Intermittent hepatic vein balloon occlusion could potentially be a low-risk adjunctive maneuver for thermal ablation therapy in the treatment of large tumors and tumors adjacent to large vessels.

Aged↗
PubMedDate not supplied

Percutaneous radiofrequency ablation of hepatocellular carcinoma in the presence of portal vein thrombosis.

Portal vein thrombosis (PVT) may not be an absolute contraindication for hepatic radiofrequency ablation (RFA). Although the data are sparse, PVT is commonly considered a contraindication to RFA. PVT has actually been described as a complication following RFA. RFA was used to treat a 3.9 x 2.9 cm primary hepatocellular carcinoma (HCC) in a patient with concomitant PVT without complication. RFA can be safely performed in this setting but further studies could clarify this issue.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Using positron emission tomography 2-deoxy-2-[18F]fluoro-D-glucose, 11CO, and 15O-water for monitoring androgen independent prostate cancer.

PURPOSE: Monitoring of androgen independent prostate cancer (AIPC) therapy involves monitoring prostate specific antigen (PSA) blood serum concentrations; however, the reliability of small changes in PSA values has been questioned. We performed a small pilot study to determine whether PET might be a useful monitor of changes during anti-angiogenic therapy in AIPC. PROCEDURES: Changes in tumor blood flow ([15O] water), blood volume ([11C]CO), 2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake and metabolic volume were measured before and during thalidomide treatment and compared with changes in PSA in six patients with AIPC. RESULTS: The percent change in PSA correlated with the FDG Delta%SUV(mean) (r=0.94, P<0.01) and Delta%metabolic tumor volume (r=0.91, P<0.01) but less well with Delta%blood volume (r=0.65, P=0.14). Percent change blood flow values showed an inverse correlation with percent changes in PSA (r=-0.83, P=0.032). CONCLUSIONS: PET measures of tumor blood flow and metabolism may have use in monitoring the physiologic changes occurring during anti-angiogenic therapy in AIPC.

Aged↗
PubMedDate not supplied

Report from the society for biological therapy and vascular biology faculty of the NCI workshop on angiogenesis monitoring.

The field of tumor angiogenesis has seen explosive growth over the last 5 years. Preclinical as well as early clinical evaluation of novel compounds is progressing at a rapid pace. To gain a perspective on the field and to take stock of advances in the understanding of molecular mechanisms underlying the process of tumor angiogenesis as well as ways of monitoring the activity of agents, the Society for Biologic Therapy and the National Cancer Institute's Vascular Biology Faculty convened a Workshop on Angiogenesis Monitoring in November 2002. The Workshop was composed of invited speakers and participants from academia, industry, and government. It was divided into 3 sessions, each chaired by leaders in the field. The first focused on advances in the understanding of the cellular and molecular mechanisms of angiogenesis in tumors. The second examined preclinical assay systems that are useful in vascular biology. The third addressed the translation to the clinic and monitoring of antiangiogenic activity of agents in patients and novel trial designs. What follows is a summary of the discussions and findings of each session.

Animals↗
PubMedDate not supplied

Special techniques for imaging blood flow to tumors.

In this review, the current imaging methods of assessing tumor perfusion are discussed and compared. Because most of the techniques depend on the administration of contrast agents, we first consider some general principles underlying the fate of contrast agents and their behavior inside the unique vascular environment of tumors.

Animals↗
PubMedDate not supplied

Successful outcome after surgical management in two cases of the "painful variant" of Hashimoto's thyroiditis.

OBJECTIVE: To describe two cases of the rare "painful variant" of Hashimoto's thyroiditis (HT) that were refractory to medical management and in which surgical intervention provided the definitive treatment. METHODS: We thoroughly review the clinical history as well as the laboratory, imaging, and surgical pathology data in these cases, and follow-up of the clinical response over time is provided. The relevant literature is also discussed. RESULTS: A 56-year-old woman, who had remotely undergone a left hemithyroidectomy and had been diagnosed with HT, sought further assessment because of neck pain and edema. Treatment with corticosteroids was partially successful but led to the development of Cushing's syndrome. A 32-year-old man had pain and swelling of the thyroid and was diagnosed with HT shortly thereafter. Levothyroxine treatment was unsuccessful. Both patients underwent thyroidectomy. Chronic lymphocytic thyroiditis (HT) with a variable degree of fibrosis was found on assessment of pathology specimens. The patients remained asymptomatic after the surgical procedure and did not require any further anti-inflammatory therapy. CONCLUSION: In selected cases, surgical treatment may become necessary for effective and permanent control of symptoms and local signs in painful HT. Access to experienced endocrine surgeons is important in order to avoid postoperative complications because the thyroid gland may be small or fibrosed in this rare variant of HT.

Adult↗