Citations

ABSTRACT Human immunodeficiency virus type 1 (HIV-1), feline immunodeficiency virus (FIV), and Moloney murine leukemia virus (MoMLV) integrases were stably expressed to determine their intracellular trafficking. Each lentiviral integrase localized to cell nuclei in close association with chromatin while the murine oncoretroviral integrase was cytoplasmic. Fusions of pyruvate kinase to the lentiviral integrases did not reveal transferable nuclear localization signals. The intracellular trafficking of each was determined instead by the transcriptional coactivator LEDGF/p75, which was required for nuclear localization. Stable small interfering RNA expression eliminated detectable LEDGF/p75 expression and caused dramatic, stable redistribution of each lentiviral integrase from nucleus to cytoplasm while the distribution of MoMLV integrase was unaffected. In addition, endogenous LEDGF/p75 coimmunoprecipitated specifically with each lentiviral integrase. In vitro integration assays with preintegration complexes (PICs) showed that endogenous LEDGF/p75 is a component of functional HIV-1 and FIV PICs. However, HIV-1 and FIV infection and replication in LEDGF/p75-deficient cells was equivalent to that in control cells, whether cells were dividing or growth arrested. Two-long terminal repeat circle accumulation in nondividing cell nuclei was also equivalent to that of LEDGF/p75 wild-type cells. Virions produced in LEDGF/p75-deficient cells had normal infectivity. We conclude that LEDGF/p75 fully accounts for cellular trafficking of diverse lentiviral, but not oncoretroviral, integrases and is the main lentiviral integrase-to-chromatin tethering factor. While lentiviral PIC nuclear import is unaffected by LEDGF/p75 knockdown, this protein is a component of functional lentiviral PICs. A role in HIV-1 integration site distribution merits investigation.

Abstract Macrophage inflammatory protein–1α (MIP-1α) gene expression is abnormally regulated in multiple myeloma (MM) owing to imbalanced expression of the acute myeloid leukemia–1A (AML-1A) and AML-1B transcription factors. We hypothesized that the increased expression ratios of AML-1A to AML-1B also induced abnormal expression of other hematopoietic and bone-specific genes that contribute to the poor prognosis of MM patients with high levels of MIP-1α. We found that interleukin-3 (IL-3) was also induced by the imbalanced AML-1A and AML-1B expression in myeloma. IL-3 mRNA levels were increased in CD138+ purified myeloma cells with increased AML-1A–to–AML-1B expression from MM patients, and IL-3 protein levels were significantly increased in freshly isolated bone marrow plasma from MM patients (66.4 ± 12 versus 22.1 ± 8.2 pg/mL; P = .038). IL-3 in combination with MIP-1α or receptor activator of nuclear factor–kappa B ligand (RANKL) significantly enhanced human osteoclast (OCL) formation and bone resorption compared with MIP-1α or RANKL alone. IL-3 stimulated the growth of interleukin-6 (IL-6)–dependent and IL-6–independent myeloma cells in the absence of IL-6, even though IL-3 did not induce IL-6 expression by myeloma cells. These data suggest that increased IL-3 levels in the bone marrow microenvironment of MM patients with imbalanced AML-1A and AML-1B expression can increase bone destruction and tumor cell growth.

AbstractIslet cell carcinoma (ICC) of the pancreas is a rare, indolent malignancy associated with higher resectability rate and better survival than ductal carcinoma. This retrospective study presents results of surgical treatment from a single institution. From 1985 through 1993 a total of 64 patients (36 men, 28 women) were surgically treated for ICC. Ages ranged from 22 to 80 years (median 55 years) with a median postoperative follow‐up of 39 months (range 10–97 months). Of the 64 patients, 30 (47%) had functioning and 34 (53%) nonfunctioning tumors. Gastrinoma (n= 11) followed by glucagonoma (n= 6) and insulinoma (n= 4) were the most common functioning tumors. In the patients undergoing a laboratory study, 67% of the nonfunctioning tumors had elevated peptide hormone levels. Potentially curative resections were performed in 17 patients (26%), palliative procedures in 35 (55%), and exploratory laparotomy alone in 12 (19%). One patient (2%) died within 30 days after operation. Symptomatic improvement was achieved in 96% of patients with a mean duration of 22 months. Three‐ and five‐year survivals were 66% and 49%, respectively. In patients with curative resection, the disease‐free survival at 3 years was 53% (95% CI: 32–86%). The presence of diffuse hepatic metastases was a predictor of poor survival at 3 years (74% versus 58%;p= 0.05); there was no statistically significant difference in survival between functioning and nonfunctioning groups (p> 0.1). Although curative resection for ICC is rare, meaningful palliation can be achieved in most patients with rare mortality and acceptable morbidity.

AbstractEighty‐two children and adolescents (18 males, 64 females; median age 14 years) surgically treated for Graves’ disease at a single institution between 1979 and 1993 were retrospectively reviewed. Most of the patients (74%) coming to thyroidectomy had been treated medically for a period ranging from 2 to 80 (median 15) months. Bilateral subtotal thyroid resection was the most frequently performed procedure (86%). Postoperatively, no permanent recurrent laryngeal nerve palsy or permanent hypocalcemia occurred. Operative mortality was zero. With a median follow‐up of 8.3 years, recurrent hyperthyroidism occurred in five patients (6%), one of whom required reoperation. Most children and adolescents with Graves’ disease can be rendered euthyroid by nonsurgical treatment options. However, prolonged and ineffective medical treatment should be avoided in these patients who are in the formative years of their lives. Surgical treatment, when indicated and employed, offers young patients with Graves’ disease a safe, rapid, definitive, cost‐effective treatment with a high success rate.

AbstractSurgical treatment for adrenal disease may be withheld from elderly patients because of concern about prohibitive operative morbidity and mortality. To obtain objective data in our practice, we analyzed the results of adrenalectomy for patients aged 65 years and older. From 1984 to 1993 there were 85 patients (41 men, 44 women) with ages ranging from 65 to 84 years (median 69 years) who underwent adrenalectomy for Cushing syndrome (n= 19), pheochromocytoma (n= 16), adrenocortical carcinoma (n= 7), benign adenoma (n= 26), or primary hyperaldosteronism (n= 17) at our institution. Median follow‐up was 26 months (range 1 month to 9.1 years). A retrospective review with respect to preoperative risks and postoperative morbidity and mortality was performed utilizing the American Society of Anesthesiologists (ASA) physical status classification and the modified Goldman multifactorial cardiac risk scheme. Survival was estimated by the Kaplan‐Meier methods. Operative mortality was 7% (six patients). No patients with pheochromocytoma or primary hyperaldosteronism died during the postoperative period. Patients undergoing adrenalectomy for adrenocortical carcinoma had a significantly higher operative mortality (43%) (p= 0.006). Postoperative complications developed in 19 patients (22%), and there was a reoperation rate of 6% (5 patients). Nineteen percent of patients required postoperative intensive care admission and had a median stay of 2 days (range, 1–38 days). Median hospital stay was 7 days (range 3–47 days). Seventy‐three patients (86%) remained alive at study completion. Two‐ and five‐year survivals were 86% and 84%, respectively. Goldman class II or greater was an excellent predictor of increased morbidity (p= 0.032) and mortality (p= 0.036). With the exception of adrenocortical carcinoma, adrenal surgery for elderly patients can be performed with acceptable morbidity and mortality. The Goldman multifactorial cardiac risk scheme reliably predicts postoperative outcome in this elderly group of patients.