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A L Feldman

Publications and source records attributed to A L Feldman.

16 recordsLinked to original sources
PubMed2002

Microarray gene expression profiling of angiogenesis inhibitors using the rat aortic ring assay.

The rat aortic ring assay has been previously described as a useful ex vivo model for analyzing the biological activity of various inhibitors of angiogenesis. Rat aortic rings are exposed to antiangiogenic agents for a five-day incubation period. Then, the degree of microvessel outgrowth from the rings is analyzed and quantified. In contrast to most in vitro angiogenesis assays, the rat aortic ring model provides a unique microenvironment to evaluate the interaction of various cell types and biological factors for their influence on angiogenesis. Microarray analysis is an accepted method for the evaluation of gene expression profiles and can be used to better understand changes in gene expression that occur when rat aortic rings are exposed to a particular biological agent. Here we describe a method of using microarray technology to evaluate the modulation of gene expression in angiogenesis using the rat aortic ring assay.

Angiogenesis Inhibitors↗
PubMed2002

Advantages of mRNA amplification for microarray analysis.

Expanding applications of cDNA microarrays such as fine needle aspiration biopsy and laser capture microdissection necessitate the ability to perform arrays with minute starting amounts of RNA. While methods for amplifying RNA have been advocated, the fidelity of array results using amplified material has not been fully validated. Here we demonstrate preserved fidelity in arrays using one or two rounds of mRNA amplification, validated by downstream real-time quantitative PCR. In addition, the quality of the array data was superior to that obtained using total RNA. Based on these results, we recommend routine mRNA amplification for all cDNA microarray-based analysis of gene expression.

Animals↗
PubMed2002

Noninvasive fluorescent imaging reliably estimates biomass in vivo.

Whole-body optical imaging of small animals has emerged as a powerful, user friendly, and high-throughput tool for assaying molecular and cellular processes as they occur in vivo. As with any imaging method, the utility of such technology relies on its ability to provide quantitative, biologically meaningful information about the physiologic or pathologic process of interest. Here we used an animal tumor model to evaluate the extent of correlation between noninvasively measured fluorescence and more traditional measurements of biomass (tumor volume and tumor weight). C57/BL6 mice were injected subcutaneously with murine colon adenocarcinoma cells that were engineered to express GFP. Serial measurements of fluorescence intensities were performed with a macroscopic in vivo fluorescence system. The progressive increases in intensity correlated strongly with growth in tumor volume, as determined by caliper measurements (R2 = 0.99). A more stringent correlation was found between fluorescence intensity and tumor weight (R2 = 0.97) than between volume and weight (R2 = 0.89). In a treatment experiment using tumor necrosis factor-alpha, fluorescence intensity (but not tumor volume) was able to differentiate between treated and control groups on day 1 post-treatment. These results validate the ability of noninvasive fluorescent imaging to quantify the number of viable, fluorescent cells in vivo.

Adenocarcinoma↗
PubMed2001

Effect of retroviral endostatin gene transfer on subcutaneous and intraperitoneal growth of murine tumors.

BACKGROUND: Inhibiting tumor angiogenesis is a promising new strategy for treating cancer. Difficulties with the stability, manufacture, and long-term administration of recombinant antiangiogenic proteins have prompted investigators to use gene therapy to generate these proteins in vivo. We investigated whether transfer of the gene encoding the angiogenesis inhibitor endostatin into the murine liver cell line NMuLi could inhibit tumor growth in vivo. METHODS: NMuLi cells were transduced with retroviral vectors containing the murine endostatin gene. The presence and function of endostatin in transduced cell supernatants were confirmed by competitive enzyme immunoassay and endothelial cell proliferation assays. Nude mice were given a subcutaneous or intraperitoneal injection with NMuLi cells, control transduced cells (NEF-null), or endostatin-transduced clones (NEF-Endo1 to 4) and were monitored for tumor growth. All statistical tests were two-sided. RESULTS: Supernatants from the clone secreting the lowest amount of endostatin (NEF-Endo4, 28 ng/mL) inhibited endothelial cell proliferation by 6% (95% confidence interval [CI] = 0% to 12%), and those from the clone secreting the highest amount (NEF-Endo1, 223 ng/mL) inhibited endothelial cell proliferation by 20% (95% CI = 13% to 27%). Increased levels of endostatin were detected in tumor lysates, but not serum, of mice given a subcutaneous injection of NEF-Endo1 cells. After 63 days, mice given a subcutaneous injection of parental NMuLi or NEF-null cells had tumor volumes of 2400 mm(3) (95% CI = 1478 mm(3) to 3300 mm(3)) and 2700 mm(3) (95% CI = 2241 mm(3) to 3144 mm(3)), respectively, compared with mean tumor volumes of less than 30 mm(3) in mice given an injection of NEF-Endo clones, a statistically significant difference (P<.001). After 123 days, all 16 mice given an intraperitoneal injection of parental NMuLi or NEF-null cells had died, compared with only three (9%) of 32 mice given an injection of NEF-Endo clones. CONCLUSIONS: Retroviral endostatin gene transfer leads to secretion of functional endostatin that is sufficiently active to inhibit tumor growth. Further studies of retroviral endostatin gene transfer for the treatment of cancer are warranted.

Angiogenesis Inhibitors↗
PubMed2001

Serum endostatin levels are elevated in patients with soft tissue sarcoma.

BACKGROUND: Solid tumors are angiogenesis dependent, and elevated levels of proangiogenic cytokines have been reported in a variety of histologies. Endostatin is an antiangiogenic fragment of the basement membrane protein, collagen XVIII. Because antiangiogenic protein fragments may be generated by tumor-derived proteases, the authors sought to determine whether circulating levels of endostatin were elevated in patients with localized soft tissue sarcoma. METHODS: The authors analyzed preoperative serum levels of endostatin, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) in 25 patients (14 males and 11 females; mean age, 44 years) with soft tissue sarcoma. For each serum sample, two aliquots were assayed in duplicate using a competitive enzyme immunoassay. Serum levels were compared with levels from 34 age-matched and gender-matched volunteer blood donors. RESULTS: Endostatin levels were significantly higher in sera from sarcoma patients than in sera from healthy controls (43.0 ng/mL vs. 25.8 ng/mL, respectively; P = 0.0002; Mann-Whitney U test). Significant elevations also were noted in VEGF and bFGF levels (P = 0.0002 and P = 0.0001, respectively). Furthermore, endostatin levels > 2 standard deviations above the control mean (55 ng/mL) were associated with an increased risk of tumor recurrence after resection (P = 0.047; log-rank test). CONCLUSIONS: Serum endostatin, VEGF, and bFGF levels are elevated in patients with soft tissue sarcoma. Elevated endostatin levels appear to be associated with tumor aggressiveness. The role of these cytokines in sarcoma angiogenesis and as potential targets for therapy warrants further study.

Adult↗
PubMed2001

A prospective analysis of plasma endostatin levels in colorectal cancer patients with liver metastases.

BACKGROUND: Circulating inhibitors of angiogenesis have been suggested to affect the growth of distant micrometastatic disease in patients with cancer. This study was designed to evaluate circulating endostatin levels in colorectal cancer patients with liver metastases. METHODS: Plasma samples from 30 colorectal cancer patients with liver metastases were analyzed for endostatin and vascular endothelial growth factor (VEGF) by using competitive enzyme immunoassays. Samples were compared with plasma from age- and sex-matched healthy controls; values >2 SD above the control mean were considered elevated. RESULTS: Plasma endostatin levels were significantly higher in the 30 cancer patients than controls (P < .0001) and correlated with preoperative VEGF levels (P = .0008). Eighteen patients underwent surgical treatment (liver resection, n = 10; or isolated hepatic perfusion with melphalan, n = 8). Seventeen treated patients were available for follow-up. Eight of 11 patients who progressed had elevated plasma endostatin levels at the time of progression. None of six patients who remained progression free had elevated endostatin levels at last follow-up (P = .02). CONCLUSIONS: Plasma endostatin levels are elevated in colorectal cancer patients with liver metastases and correlate with VEGF levels. Elevated endostatin levels during follow-up are associated with disease progression. Understanding the role of endogenous endostatin in cancer patients may lead to novel strategies to inhibit tumor angiogenesis.

Adult↗
PubMed2000

Progress in antiangiogenic gene therapy of cancer.

BACKGROUND: Because tumors require angiogenesis for growth, inhibiting angiogenesis is a promising strategy for treating cancer patients. Although numerous endogenous angiogenesis inhibitors have been discovered, the clinical evaluation of these agents has been hindered by high dose requirements, manufacturing constraints, and relative instability of the corresponding recombinant proteins. Therefore the delivery of these proteins using gene therapy has become increasingly attractive. METHODS: Based on their own antiangiogenic gene therapy research, the authors evaluated the published experience with antiangiogenic gene therapy models using the National Library of Medicine's PubMed search service and the reference lists of the publications cited. RESULTS: Greater than 40 endogenous inhibitors of angiogenesis have been characterized. Thirteen have been employed in gene therapy models, all of which showed antitumor activity in experimental animals. Other approaches have inhibited the expression or activity of proangiogenic cytokines such as vascular endothelial growth factor. The ideal gene delivery vector would target tumor tissue preferentially to minimize systemic toxicity of the transgene product. However, the low toxicity profile of endogenous inhibitors of angiogenesis has allowed the success of systemic antiangiogenic gene therapy in a number of preclinical models, in which normal host tissues act as a "factory" to produce high circulating concentrations of antiangiogenic proteins. CONCLUSIONS: Difficulties with the large-scale use of antiangiogenic agents have hindered their investigation in clinical trials. Antiangiogenic gene therapy offers the potential for cancer patients to manufacture their own antiangiogenic proteins. This strategy has been increasingly successful in preclinical models and represents an exciting new approach to cancer therapy.

Animals↗
PubMed2000

The angiogenesis inhibitor, endostatin, does not affect murine cutaneous wound healing.

BACKGROUND: Endostatin is a potent angiogenesis inhibitor, which is currently being used in Phase I trials as an antitumor agent. The purpose of this study was to determine whether endostatin has an effect on wound healing in a murine model. MATERIALS AND METHODS: The function of endostatin was confirmed using a human microvascular endothelial cell (HMVEC) proliferation assay in which cells are treated for 4 days with growth media plus or minus endostatin. Full-thickness incisions were made on the dorsum of athymic nude mice and closed primarily with skin staples. PVA sponges were implanted in some wounds to determine vascular ingrowth. Subsequently, mice were treated with recombinant human endostatin at 20 mg/kg/day or 50 mg/kg/dose BID versus control for a total of 14 days. On Days 2, 4, 8, 12, and 16, three mice per group had serum samples drawn and were sacrificed. Perpendicular breaking strength (N) was determined using an Instron 5540 tensometer. Wound strength was determined by dividing breaking strength by wound area (N/cm(2)). Vascular density in sponges was determined using CD31 immunohistochemistry. Serum endostatin concentrations were determined using a commercially available ELISA kit. RESULTS: Endostatin caused a significant reduction of endothelial cell proliferation after 4 days compared to media alone (72%, P = 0.031). At all time points tested, there was no statistical difference in the wound-breaking strength between endostatin and control-treated mice at either the low or high dose. Serum endostatin levels were consistently 10-fold higher in endostatin-treated mice than in controls. No differences in vascular density were seen in endostatin versus control-treated mice as determined by CD31 immunohistochemistry of PVA sponges. CONCLUSION: Therapy with human endostatin does not induce a significant decrease in breaking strength of cutaneous wounds in mice.

Animals↗
PubMed2000

Antiangiogenic gene therapy of cancer utilizing a recombinant adenovirus to elevate systemic endostatin levels in mice.

Gene therapy represents a possible alternative to the chronic delivery of recombinant antiangiogenic proteins to cancer patients. Inducing normal host tissues to produce high circulating levels of these proteins may be more effective than targeting antiangiogenic genes to tumor tissue specifically. Previously reported gene therapy approaches in mice have achieved peak circulating endostatin levels of 8-33 ng/ml. Here we report plasma endostatin levels of 1770 ng/ml after administration of a recombinant adenovirus. Growth of MC38 adenocarcinoma, which is relatively resistant to adenoviral infection, was inhibited by 40%. These findings encourage gene delivery approaches that use the host as a "factory" to produce high circulating levels of antiangiogenic agents.

Adenoviridae↗
PubMed2000

Serum endostatin levels are elevated and correlate with serum vascular endothelial growth factor levels in patients with stage IV clear cell renal cancer.

Clear cell renal carcinoma (CCRC) is a highly angiogenic tumor known to secrete vascular endothelial cell growth factor (VEGF). Endostatin is an endogenous antiangiogenic agent with antitumor activity in mice. The purpose of this study was to evaluate serum levels of endostatin in normal subjects and in patients with CCRC and to examine the relationship of these levels to circulating VEGF levels. Fifteen patients (mean age, 48 years) on a clinical protocol for stage IV CCRC at the National Cancer Institute were included in the study. Archived prenephrectomy serum samples were analyzed for endostatin and VEGF concentrations. Endostatin and VEGF levels were compared with those of an age-matched group of volunteer blood donors (n = 18) using a competitive enzyme immunoassay. Data were analyzed using the Mann-Whitney U test and the Spearman rank correlation. Median serum endostatin levels were 24.6 ng/ml (range, 15.1-54.0 ng/ml) in CCRC patients versus 14.1 ng/ml (range, 1.0-19.3 ng/ml) in healthy controls (P < 0.0001). Median VEGF levels were 3.4 ng/ml (range, 0.1-11.2 ng/ml) and 2.5 ng/ml (range, 0.1-4.2 ng/ml), respectively (P = 0.065). A highly significant correlation was observed between endostatin and VEGF levels among the CCRC patients (r = 0.81, P = 0.0003) but not among controls (r = -0.22, P = 0.37). Endostatin levels are detectable in serum from healthy subjects as well as from CCRC patients. Levels are significantly elevated and correlate with VEGF levels in CCRC patients. Elucidating the nature of this correlation may lend insight into the regulation of tumor angiogenesis in patients with renal cancer.

Adenocarcinoma, Clear Cell↗
PubMed1999

Management of extremity recurrences after complete responses to isolated limb perfusion in patients with melanoma.

BACKGROUND: Despite high rates of complete responses (CRs) to isolated limb perfusion (ILP) for patients with in-transit melanoma (60% to 90%), extremity recurrences are common. We evaluated our experience with managing these recurrences to determine how best to treat these patients. METHODS: Between April 1992 and April 1998, 72 patients experienced CRs after hyperthermic ILP using Melphalan, with (n = 46) or without (n = 26) tumor necrosis factor. Of these, 25 patients (35%) experienced initial recurrences in the extremities, and they form the basis of this study. RESULTS: Three patients who underwent repeat ILP for treatment of their recurrences experienced a second CR and recurrence in the extremity (at 9, 15, and 16 months), allowing analysis of 28 cases. For 5 of 20 recurrences managed with excision, 2 of 6 managed with repeat ILP, and 0 of 2 managed with systemic treatment, the patient was free of disease at the last follow-up examination (median follow-up period, 11 months). CONCLUSIONS: Isolated extremity recurrences after CRs to ILP occurred in 35% of patients. Initially, these could be managed successfully by excision or repeat ILP for the majority of patients (92%). We recommend excision of small-volume recurrent disease, reserving repeat ILP for patients with increasing numbers of lesions or increasing rapidity of in-field recurrences.

Adult↗
PubMed1999

Results of heterotopic parathyroid autotransplantation: a 13-year experience.

BACKGROUND: The reported success of heterotopic parathyroid autotransplantation (HPA) in patients with primary hyperparathyroidism varies from 20% to 60%. The purpose of this study was to evaluate our results with HPA to help define its role in this patient group. METHODS: Between July 1985 and June 1998, 44 patients underwent 51 HPA procedures at our institution. Twenty to 25 fragments of parathyroid tissue measuring 1 to 3 mm3 each were placed into the forearm musculature. HPA results were scored as nonfunctional (requiring calcium and vitamin D), partially functional (normocalcemia on calcium alone), fully functional (normocalcemia without supplementation), or hyperfunctional (hypercalcemia without supplementation). RESULTS: Follow-up data were available for 39 patients who underwent 46 autografts (20 immediate and 26 cryopreserved). With a median follow-up of 35 months, 19 autografts (41%) were nonfunctional; 9 autografts (20%) were partially functional; 15 autografts (33%) were fully functional, and 3 autografts (7%) were hyperfunctional. Full function was observed in 35% of immediate and 31% of delayed autografts. CONCLUSIONS: One third of parathyroid autografts develop full function, and an additional one fifth develop partial function. Recurrent hyperparathyroidism is uncommon. No benefit was observed from immediate versus delayed HPA, and the modest success rate of HPA suggests that improvements in technique are warranted.

Adenoma↗
PubMed1998

Long-term outcome in women less than 30 years of age with breast cancer.

BACKGROUND AND OBJECTIVES: Young age at diagnosis is associated with poor prognosis in female breast cancer, but few studies report long-term outcome in women less than 30 years of age. We evaluated 30-year survival in this patient population. METHODS: A retrospective analysis was performed of 29 women less than 30 years of age who were diagnosed with breast cancer between the years 1953 and 1983. All but two patients were followed either until death or for a minimum of 30 years. RESULTS: Actuarial 30-year survival was 19% for the entire group and 10% for women with invasive ductal carcinoma. Twenty-two (92%) of 24 deaths were due to metastatic breast cancer, including three deaths occurring after disease-free intervals of more than 12 years. CONCLUSIONS: Breast cancer in our study population of women less than 30 years of age was a highly lethal disease, particularly in patients with invasive ductal carcinoma. The phenomenon of late death after a long disease-free interval is important in the interpretation of data reflecting newer forms of breast cancer treatment.

Adult↗
PubMed1993

Pneumothorax in polysubstance-abusing marijuana and tobacco smokers: three cases.

Three patients are reported who suffered spontaneous pneumothorax, each of whom also had a history of daily marijuana and tobacco use. The patients ranged in age from 24 to 37 years, had smoked marijuana on a daily basis for 10 to 14 years, and had 11 to 50 pack-year tobacco-smoking histories. Marijuana may predispose to pneumothorax both by accelerating tobacco-induced lung disease, and by the frequent performance of the Valsalva maneuver during marijuana smoking. Although there is an association between pneumothorax and heavy tobacco use, an association with chronic daily marijuana use has not previously been reported.

Adult↗