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Kross RA, Ferri E, Leung D, Pratila M, Broad C, Veronesi M, Melendez JA. A comparative study between a calcium channel blocker (Nicardipine) and a combined alpha-beta-blocker (Labetalol) for the control of emergence hypertension during craniotomy for tumor surgery. Anesth Analg 2000; 91:904-9. [PMID: 11004045 DOI: 10.1097/00000539-200010000-00024] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We compared the efficacy of the combination of enalaprilat/labetalol with that of enalaprilat/nicardipine to prevent emergence postcraniotomy hypertension. A prospective, randomized open labeled clinical trial was designed to compare the incidence of breakthrough hypertension (systolic blood pressure [SBP] > 140 mm Hg) and adverse effects (hypotension, tachycardia, and bradycardia) between the two drug combinations. Secondarily, the effects of the drugs on SBP, mean blood pressure, and diastolic blood pressure were evaluated over the course of the study. Forty-two patients received enalaprilat 1.25 mg IV at dural closure followed by either multidose nicardipine 2 mg IV or labetalol 5 mg IV to maintain the SBP below 140 mm Hg. SBP was similarly controlled in both groups. There was a marginally smaller incidence of failures and adverse effects with labetalol. Blood pressure profiles were similar for both groups.
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de Alava E, Antonescu CR, Panizo A, Leung D, Meyers PA, Huvos AG, Pardo-Mindán FJ, Healey JH, Ladanyi M. Prognostic impact of P53 status in Ewing sarcoma. Cancer 2000. [PMID: 10951341 DOI: 10.1002/1097-0142(20000815)89:4<783::aid-cncr10>3.0.co;2-q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Disease stage at the time of diagnosis and response to therapy are the main prognostic factors for patients with Ewing sarcoma or peripheral neuroectodermal tumor (ES/PNET). The primary genetic alteration in ES/PNET, the fusion of the EWS gene with FLI1 or ERG, is diagnostically highly specific for these tumors, and molecular variation in the structure of the EWS-FLI1 fusion gene also is of prognostic significance. In contrast, secondary genetic alterations, such as P53 alterations, are relatively uncommon in ES/PNET, and their prognostic impact has not been extensively studied. METHODS Prechemotherapy, paraffin embedded, nondecalcified, primary tumor material in a well-characterized series of 55 patients with ES/PNET with defined EWS-FLI1 fusion transcripts (32 patients with type 1 and 23 patients with other types) was studied retrospectively by immunohistochemical techniques for cell cycle regulators and proliferative markers, such as P53, P21(WAF1), and Ki-67, as well as by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) technique for apoptosis. Nuclear P53 expression in > 20% of tumor cells was scored as aberrant overexpression. Histologic response to neoadjuvant chemotherapy was assessed. RESULTS Aberrant P53 expression (in > 20% of tumor cells) was present in 6 patients (11%) but showed no statistically significant correlation with disease stage, tumor size, proliferation rate (Ki-67), apoptotic rate (TUNEL), or EWS-FLI1 fusion type. By univariate analysis, the P53 > 20% group showed a significantly poorer overall survival among patients with localized disease (n = 43 patients) (P = 0.001) and in the entire study group (P = 0.01). In multivariate Cox analyses of overall survival, P53 > 20% was the strongest negative factor among prognostic factors available at the time of diagnosis (P = 0.001; relative risk [RR] = 9) and when chemotherapy response was included in the analysis (P53 > 20%: P = 0.01; RR = 10). CONCLUSIONS P53 alteration appears to define a small clinical subset of patients with ES/PNET with a markedly poor outcome. The current observations warrant a systematic prospective study with comprehensive P53 mutation analysis. [See related article on pages 793-9, this issue.]
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Yang K, Lamprecht SA, Liu Y, Shinozaki H, Fan K, Leung D, Newmark H, Steele VE, Kelloff GJ, Lipkin M. Chemoprevention studies of the flavonoids quercetin and rutin in normal and azoxymethane-treated mouse colon. Carcinogenesis 2000; 21:1655-60. [PMID: 10964096 DOI: 10.1093/carcin/21.9.1655] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In this study we investigated the chemopreventive effects of quercetin and rutin when added to standard AIN-76A diet and fed to normal and azoxymethane (AOM)-treated mice. Early changes in colonic mucosa were analyzed, including colonic cell proliferation, apoptotic cell death, cyclin D(1) expression and focal areas of dysplasia (FAD). The findings show that the number of colonic epithelial cells per crypt column increased (P: < 0.01) in each normal mouse group fed the flavonoids; AOM administration increased colonic crypt cell proliferation and resulted in a marked rise of bromodeoxyuridine-labeled cells in the lower proliferative zone of the crypt. Both supplementary dietary quercetin and rutin increased the apoptotic index and caused a redistribution of apoptotic cells along the crypt axis in normal mice fed a standard AIN-76A diet. The number of apoptotic cells/column and apoptotic indices markedly increased (P: < 0.01) in the AOM-treated group compared with untreated animals; apoptotic cells expanded throughout the colonic crypts after flavonoid supplementation and AOM administration. Positive cyclin D(1) expression was detected in mice on diets supplemented either with quercetin (P: < 0.01) or rutin (P: < 0.05). AOM administration resulted in the formation of FAD. Both the number of mice exhibiting FAD and the total numer of FAD observed were significantly reduced (P: < 0.01) in AOM-treated animals fed flavonoids compared with mice maintained on the standard AIN-76A diet. Surprisingly, however, quercetin alone was able to induce FAD in 22% of normal mice fed the standard AIN-76A diet.
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Krug LM, Ng KK, Kris MG, Miller VA, Tong W, Heelan RT, Leon L, Leung D, Kelly J, Grant SC, Sirotnak FM. Phase I and pharmacokinetic study of 10-propargyl-10-deazaaminopterin, a new antifolate. Clin Cancer Res 2000; 6:3493-8. [PMID: 10999734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The 10-deazaaminopterins are a new class of rationally designed antifolates demonstrating greater antitumor effects than methotrexate in murine tumor models and human tumor xenografts. Their design was aimed at improving membrane transport and polyglutamylation in tumor cells, resulting in increased intracellular accumulation and enhanced cytotoxicity. Compared with other 4-aminofolate analogues, 10-propargyl-10-deazaaminopterin (PDX) is the most efficient permeant for the RFC-1-mediated internalization and substrate for folylpolyglutamate synthetase. PDX demonstrates greater in vitro and in vivo antitumor efficacy than methotrexate or edatrexate. We undertook a Phase I study with PDX to identify the potential toxicities and define an optimal dose and schedule. Thirty-three patients were enrolled, all of whom had non-small cell lung cancer (NSCLC) and were treated previously with a median of two prior chemotherapy regimens. Initially, PDX was administered weekly for 3 weeks in a 4-week cycle. Mucositis requiring dose reduction and/or delay in the first cycle occurred in four of six patients treated at the initial dose level (30 mg/m2), making this the maximal tolerated dose for PDX given on this schedule. The treatment schedule was then modified to every 2 weeks. Twenty-seven patients were treated twice weekly with a total of 102 four-week cycles (median, 2 cycles/patient). Mucositis was the dose-limiting toxicity, with grade 3 and 4 mucositis occurring in the first two patients treated at the 170 mg/m2 dose level. Other toxicities were mild and reversible. No neutropenia was observed. The recommended Phase II dose is 150 mg/m2 biweekly. At that dose level, the mean area under the curve was 20.6 micromol x h, and the mean terminal half-life was 8 h. Two patients with stage IV NSCLC had major objective responses, and five patients had stable disease for 7 (two patients), 9 (one patient), 10 (one patient), and 13 months (one patient). PDX is a new antifolate with manageable toxicity and evidence of antitumor activity in NSCLC. A Phase II trial in NSCLC and a Phase I trial with paclitaxel are under way. These studies will also quantitate the expression of genes controlling internalization (RFC-1) and polyglutamylation of PDX in tumor cells as correlates of response.
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Wei G, Antonescu CR, de Alava E, Leung D, Huvos AG, Meyers PA, Healey JH, Ladanyi M. Prognostic impact of INK4A deletion in Ewing sarcoma. Cancer 2000; 89:793-9. [PMID: 10951342 DOI: 10.1002/1097-0142(20000815)89:4<793::aid-cncr11>3.0.co;2-m] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND The primary genetic alteration in > 95% of Ewing sarcomas (ES) is a specific fusion of EWS with FLI1 or ERG. Secondary genetic alterations possibly involved in progression of ES are not well understood. A recent study found loss of the negative cell cycle regulator gene INK4A in 8 of 27 ES samples (30%). To confirm these findings and evaluate their prognostic significance, the authors studied INK4A deletion in 41 ES samples from 39 patients. METHODS Using Southern blot analysis with an INK4A p16 cDNA probe, the intensity of the INK4A bands in ES DNA samples was normalized to that of a control probe and compared with nondeleted control DNA; > 50% signal reduction was scored as evidence of deletion. All ES tumor DNA samples previously were confirmed to have EWS rearrangements on the same Southern blots, using a cDNA probe spanning the EWS breakpoint region. RESULTS Tumors from 7 patients (18%) showed INK4A deletion independent of disease stage (localized or metastatic) or sample source (primary tumor or metastasis). INK4A was a strong negative factor for disease specific survival in univariate analysis (P = 0.001) and in multivariate analysis including stage (relative risk = 6; P = 0.001). CONCLUSIONS INK4A deletions appear to be the most frequent secondary molecular genetic alteration found to date in ES. Their possible clinical usefulness in identifying a subset of ES patients with poor prognosis merits systematic prospective analysis. [See related article on pages 783-92.]
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Farzan M, Schnitzler CE, Vasilieva N, Leung D, Choe H. BACE2, a beta -secretase homolog, cleaves at the beta site and within the amyloid-beta region of the amyloid-beta precursor protein. Proc Natl Acad Sci U S A 2000; 97:9712-7. [PMID: 10931940 PMCID: PMC16930 DOI: 10.1073/pnas.160115697] [Citation(s) in RCA: 283] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Production of amyloid-beta protein (Abeta) is initiated by a beta-secretase that cleaves the Abeta precursor protein (APP) at the N terminus of Abeta (the beta site). A recently identified aspartyl protease, BACE, cleaves the beta site and at residue 11 within the Abeta region of APP. Here we show that BACE2, a BACE homolog, cleaves at the beta site and more efficiently at a different site within Abeta. The Flemish missense mutation of APP, implicated in a form of familial Alzheimer's disease, is adjacent to this latter site and markedly increases Abeta production by BACE2 but not by BACE. BACE and BACE2 respond identically to conservative beta-site mutations, and alteration of a common active site Arg inhibits beta-site cleavage but not cleavage within Abeta by both enzymes. These data suggest that BACE2 contributes to Abeta production in individuals bearing the Flemish mutation, and that selective inhibition of these highly similar proteases may be feasible and therapeutically advantageous.
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Abstract
OBJECTIVE To determine whether reresection affects survival in patients with inadequately resected, primary extremity soft tissue sarcoma. This study correlates reresection with local recurrence-free survival, metastasis-free survival, and disease-free survival. SUMMARY BACKGROUND DATA Soft tissue sarcomas are rare neoplasms, with an incidence of approximately 6,000 per year in the United States. Because these tumors are rare and benign soft tissue tumors are common, many are initially thought to be benign and are excised without wide margins. METHODS Patients who underwent treatment for primary tumors from July 1982 to June 1999 at a single institution were the subject of study. Two groups of patients were analyzed: those who underwent one definitive resection (one operation) and those whose tumors were previously resected and who were then referred for subsequent reresection (two operations). Patients were given adjuvant radiation or chemotherapy according to the standard of care. RESULTS Of 1,092 patients with primary extremity soft tissue sarcoma underwent resection, 685 underwent definitive radical resection and 407 underwent reresection after undergoing excisional resection elsewhere. Median follow-up was 4.8 years. The 5-year disease-free survival rate of the definitive resection (one operation) group was 70%; that of the reresection (two operations) group was 88%. On multivariate analysis, reresection was adjusted and controlled for age, grade, depth, size, histology, and margins. Reresection remained a significant predictor of improved disease-free survival, even after these adjustments. To determine whether this difference was stage- or referral-biased, the patient population was divided by AJCC stage. In all stages there was a trend toward improved outcome; this was most marked for those with stage III disease (>5 cm, high-grade, and deep). CONCLUSIONS Patients with extremity soft tissue sarcoma who undergo reresection with two "primary" operations have an improved survival compared with those who undergo one operation. The most plausible explanation, referral and selection bias, is questionable given the significance of reresection as a variable after adjusting for stage and other risk factors. This suggests that where indicated and possible, reresection should be liberally applied in patients with primary extremity soft tissue sarcoma.
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Wu SL, Leung D, Tretyakov L, Hu J, Guzzetta A, Wang YJ. The formation and mechanism of multimerization in a freeze-dried peptide. Int J Pharm 2000; 200:1-16. [PMID: 10845681 DOI: 10.1016/s0378-5173(99)00469-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atrial natriuretic peptide (ANP) is a peptide with 25 amino acid residues (hANP 4-28) and one intra-chain disulfide bond. We used the size-exclusion chromatography (SEC), sodium dodecyl sulfate in polyacrylamide gel electrophoresis (SDS-PAGE), and reversed-phase liquid chromatography with electrospray mass spectrometry (LC-MS) methods to examine the freeze-dried products of ANP to determine the types, sizes, and amounts of the multimer formation in different stability protocols (by varying the conditions with lyophilization cycles, excipients, storage temperatures, and times). Under the non-annealing lyophilization cycle or lyophilization with high concentration of bulking agent (mannitol), multimer formation increased with increasing storage times. Two kinds of multimers were observed; the major portion is reducible and the minor portion is non-reducible. The reducible multimers are disulfide-linked multimers as determined by LC-MS. The non-reducible multimer was mainly a dimer, possibly linked by a covalent bond between the side chain of tyrosine in one molecule and the dehydroalanine intermediate in another molecule, based on the evidences of the mass of the non-reducible dimer along with the elution position in SEC, and the change of the UV spectrum in the aromatic region. The analysis of degradants suggests that the mechanism start from an beta-elimination of disulfide linkage to form a free thiolate ion (HS-) and a dehydroalanine-type peptide intermediate. The HS- then catalyzed ANP to form the disulfide-linked multimers. The dehydroalanine-type ANP intermediate then reacted with another ANP molecule to form a non-disulfide-linked dimer through reaction with the side chain of tyrosine. These results suggest that the source of multimer formation be initiated by phase transition (from amorphous to crystalline phase) either in the freeze-dried process or during storage. That phase change may induce a drastic change in pH and moisture to damage the peptide. The detailed mechanism and the kinetics of ANP multimerization are discussed. The formation of the multimers was diminished by using the thermal treatment (the annealing step) with a proper ratio of mannitol to ANP peptide in the lyophilization, and/or increase of the acetate buffer concentration in the formulation.
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Linehan DC, Lewis JJ, Leung D, Brennan MF. Influence of biologic factors and anatomic site in completely resected liposarcoma. J Clin Oncol 2000; 18:1637-43. [PMID: 10764423 DOI: 10.1200/jco.2000.18.8.1637] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Soft tissue sarcoma (STS) encompasses a group of neoplasms that are anatomically and biologically diverse. Retroperitoneal/visceral (RP/V) tumors have a poorer prognosis than extremity/trunk (E/T) lesions, and this has been attributed to frequent presentation with tumors of large size and multiorgan involvement that precludes complete resection. The worse prognosis that is associated with RP/V tumors has also been thought to be histopathologically dependent and not necessarily related to anatomic site. The aim of this study was to determine the role of anatomic site and biologic features in prognosis and outcome in patients after complete resection by examining a large cohort of STS patients with a single histopathology, ie, liposarcoma. METHODS All patients who were treated for liposarcoma from July 1, 1982, through July 1, 1998, were included. Univariate analyses were performed using log-rank test and Kaplan-Meier estimates, and multivariate analyses were performed using Cox regression. The three end points examined were local recurrence (LR), distant recurrence, and disease-specific survival (DSS). RESULTS Seven hundred twenty patients with liposarcoma were evaluated, and of these, 460 had completely resected primary or completely resected locally recurrent disease. Breakdown of anatomic site was 65% E/T (n = 301) and 35% RP/V (n = 159). The median follow-up period for patients who underwent complete resection was 42 months (range, 1 to 194 months). We found that RP/V site is a poor prognosticator that is independent of patient sex and age; tumor size, grade, and margin; and recurrent presentation. Sixty-nine percent of patients with RP/V tumors who died had local disease only and no distant metastasis at the time of death. CONCLUSION In liposarcoma, tumor location exerts as strong an influence on prognosis as biology. In contrast to extremity liposarcoma, LR without distant metastasis often results in death for patients with RP/V tumors. For these patients, local control accomplished by complete surgical resection +/- adjuvant radiation therapy should impact strongly on DSS.
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Leung D, Abbenante G, Fairlie DP. Protease inhibitors: current status and future prospects. J Med Chem 2000; 43:305-41. [PMID: 10669559 DOI: 10.1021/jm990412m] [Citation(s) in RCA: 667] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Espat NJ, Lewis JJ, Woodruff JM, Antonescu C, Xia J, Leung D, M. F. B. Confirmed angiosarcoma: prognostic factors and outcome in 50 prospectively followed patients. Sarcoma 2000; 4:173-7. [PMID: 18521298 PMCID: PMC2395443 DOI: 10.1155/2000/575781] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Purpose. Angiosarcoma is a rare tumor with endothelial cell differentiation that may arise in any anatomic location.The purpose of this report was to identify prognostic factors on outcome in a group of prospectively followed patients with confirmed angiosarcoma.Subjects. Adult patients (>16 years old) with angiosarcoma treated between July 1982 and February 1998 were identified from a prospective database.Methods. Pathologic confirmation of all cases was performed prior to inclusion in this analysis. Various prognostic factors were evaluated for disease-specific survival. Survival was determined by the Kaplan- Meier method. Statistical significance was evaluated by log-rank test for univariate analysis and Cox stepwise regression for multivariate analysis (p<0.05).Results. Fifty patients were identified; at the initial evaluation, this group included 32 patients with a primary tumor, three with local recurrence and 15 with metastatic disease. Tumor sites included 16 head and neck and skin of head, eight extremity, seven trunk, six breast, five pelvis, four viscera and four thoracic. Median follow-up among survivors was 71 months (range, 38-191 months).Two- and 5-year disease-specific survival was 50 and 30%, respectively, with a median of 24 months. The factor predictive of tumor-related mortality was presentation status (p=0.001; relative risk, 5). Two-year disease-specific survival for patients presenting with recurrent or metastatic disease was 13%, compared with 70% for those with primary disease.
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DeMatteo RP, Lewis JJ, Leung D, Mudan SS, Woodruff JM, Brennan MF. Two hundred gastrointestinal stromal tumors: recurrence patterns and prognostic factors for survival. Ann Surg 2000; 231:51-8. [PMID: 10636102 PMCID: PMC1420965 DOI: 10.1097/00000658-200001000-00008] [Citation(s) in RCA: 1640] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To analyze the outcome of 200 patients with gastrointestinal stromal tumor (GIST) who were treated at a single institution and followed up prospectively. SUMMARY BACKGROUND DATA A GIST is a visceral sarcoma that arises from the gastrointestinal tract. Surgical resection is the mainstay of treatment because adjuvant therapy is unproven. METHODS Two hundred patients with malignant GIST were admitted and treated at Memorial Hospital during the past 16 years. Patient, tumor, and treatment variables were analyzed to identify patterns of tumor recurrence and factors that predict survival. RESULTS Of the 200 patients, 46% had primary disease without metastasis, 47% had metastasis, and 7% had isolated local recurrence. In patients with primary disease who underwent complete resection of gross disease (n = 80), the 5-year actuarial survival rate was 54%, and survival was predicted by tumor size but not microscopic margins of resection. Recurrence of disease after resection was predominantly intraabdominal and involved the original tumor site, peritoneum, and liver. CONCLUSIONS GISTs are uncommon sarcomas. Tumor size predicts disease-specific survival in patients with primary disease who undergo complete gross resection. Tumor recurrence tends to be intraabdominal. Investigational protocols are indicated to reduce the rate of recurrence after resection and to improve the outcome for patients with GIST.
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Ruebner A, Yang Z, Leung D, Breslow R. A cyclodextrin dimer with a photocleavable linker as a possible carrier for the photosensitizer in photodynamic tumor therapy. Proc Natl Acad Sci U S A 1999; 96:14692-3. [PMID: 10611274 PMCID: PMC24709 DOI: 10.1073/pnas.96.26.14692] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A cyclodextrin dimer has been synthesized with two beta-cyclodextrins linked by a flexible chain containing a carbon-carbon double bond. This dimer binds and solubilizes a phthalocyanine-based photosensitizer that generates singlet oxygen on irradiation. When the complex is irradiated, the singlet oxygen cleaves the carbon-carbon link, and the cyclodextrins are released, liberating the photosensitizer into the light path. Ideas about how this phenomenon could be used to make photodynamic tumor therapy into a more selective process are described.
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Barrera R, Melendez J, Ahdoot M, Huang Y, Leung D, Groeger JS. Flow triggering added to pressure support ventilation improves comfort and reduces work of breathing in mechanically ventilated patients. J Crit Care 1999; 14:172-6. [PMID: 10622751 DOI: 10.1016/s0883-9441(99)90031-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE The purpose of this study was to measure the effect of flow triggering (FT), added to pressure support ventilation (PSV), during spontaneous breathing in intubated patients. MATERIALS AND METHODS A prospective observational study was conducted at a Comprehensive Cancer Center, University Hospital. Fourteen consecutive critically ill, mechanically ventilated patients on PSV with positive end-expiratory pressure were studied. Flow triggering was added to PSV in spontaneously breathing ventilated patients. RESULTS Respiratory rate (f), minute ventilation (Vepsilon), patient work of breathing (WOBp), respiratory drive (P0.1), rapid shallow breathing index (f/Vt), tidal volume (Vt) and a visual analog scale of breathing effort and comfort all improved. There was a large decrease in WOBp and P0.1 when flow triggering was added to PSV (P<.001). There was a moderate decrease in f/V1 during the same procedure (P<.01). Twelve patients felt subjectively better with the intervention. CONCLUSIONS Flow triggering offers an excellent complement to PSV because it improves patient comfort and reduces the magnitude of the inspiratory effort as well as the delay time between inspiratory muscle contraction and gas flow. It augments gas exchange at no metabolic cost to the patient while reducing the work of breathing.
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Worrall BB, Rowland LP, Del Bene M, Leung D, Chin SS. Mother with amyotrophic lateral sclerosis and daughter with Creutzfeldt-Jakob disease. ARCHIVES OF NEUROLOGY 1999; 56:1502-4. [PMID: 10593306 DOI: 10.1001/archneur.56.12.1502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To describe a mother who had autopsy-proved amyotrophic lateral sclerosis and her daughter who had clinically diagnosed Creutzfeldt-Jakob disease. DESIGN Case reports with molecular genetic analyses. SETTING A tertiary care center. PATIENTS The mother had progressive upper and lower motor neuron symptoms and signs starting at the age of 54 years. Electrophysiological testing supported the diagnosis of amyotrophic lateral sclerosis. Autopsy results confirmed the diagnosis. Her daughter had received injections of human growth hormone prepared from pooled human pituitary glands as a child. At the age of 31 years, she experienced the onset of gait ataxia and dysarthria. Cerebrospinal fluid showed the 14-3-3 protein. Cognitive difficulties ensued. She progressed to a nearly akinetic and mute state. She had overt visible fasciculations and muscle atrophy in the legs. MAIN OUTCOME MEASURES AND RESULTS Neither patient carried a mutation in the prion protein gene. Both were homozygous for methionine at the polymorphic codon 129. Neither patient carried a deletion of the 5 exons of the superoxide dismutase 1 gene. CONCLUSIONS It is uncertain whether the 2 cases occurred in the same family by chance or whether the patients shared genetic risk factors for the 2 diseases. The possibility that homozygosity at codon 129 is a risk factor for amyotrophic lateral sclerosis is being tested in a case-control study.
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Nashed G, French B, Gallagher D, Hopkins A, Juergens C, Leung D, Lowe HC. Right ventricular perforation with cardiac tamponade associated with use of a temporary pacing wire and abciximab during complex coronary angioplasty. Catheter Cardiovasc Interv 1999; 48:388-9. [PMID: 10559821 DOI: 10.1002/(sici)1522-726x(199912)48:4<388::aid-ccd14>3.0.co;2-k] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe our recent experience of right ventricular perforation leading to cardiac tamponade associated with a complex coronary angioplasty in which abciximab and a temporary pacing wire were used. This is to highlight the possibility that the combined use of temporary pacing wires and the IIb/IIIa receptor antagonists may be associated with an increased risk of this serious complication. Cathet. Cardiovasc. Intervent. 48:388-389, 1999.
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Kourea HP, Cordon-Cardo C, Dudas M, Leung D, Woodruff JM. Expression of p27(kip) and other cell cycle regulators in malignant peripheral nerve sheath tumors and neurofibromas: the emerging role of p27(kip) in malignant transformation of neurofibromas. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 155:1885-91. [PMID: 10595919 PMCID: PMC1866917 DOI: 10.1016/s0002-9440(10)65508-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/24/1999] [Indexed: 02/07/2023]
Abstract
There is little information regarding the status of cell cycle regulators in malignant peripheral nerve sheath tumors (MPNSTs) and neurofibromas (NFs). In this study, we investigated patterns of expression of p53 and pRB, cyclin-dependent kinase inhibitors (CKIs) p21 and p27, as well as cyclins D1 and E, in a cohort of 35 well-characterized MPNSTs and 16 NFs. These phenotypes were correlated with proliferative index, as assessed by Ki-67, as well as clinicopathological parameters of poor outcome. p53 nuclear overexpression was found in 10 of 35 (29%) MPNSTs, and it was lacking in NFs (P = 0.02). There were no differences in the patterns of expression of pRB, cyclin D1, and p21 between MPNSTs and NFs. However, p27 nuclear expression was present in most NFs, but it was absent in the majority of MPNSTs, which displayed cytoplasmic staining (P < 0.001). Nuclear cyclin E expression was more pronounced in MPNSTs than in NFs. We observed inverse patterns of expression for nuclear p27 and nuclear cyclin E expression. The staining profiles of cytoplasmic p27 and nuclear cyclin E expression were found to be statistically associated (P = 0.01). High Ki-67 expression was found in 20 of 34 (59%) MPNSTs but was absent in NFs (P < 0.001). Furthermore, detection of cytoplasmic p27 expression was found to be a prognostic factor for poor survival in MPNSTs (P = 0.03, relative risk = 2.4).
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Brinkworth RI, Fairlie DP, Leung D, Young PR. Homology model of the dengue 2 virus NS3 protease: putative interactions with both substrate and NS2B cofactor. J Gen Virol 1999; 80 ( Pt 5):1167-1177. [PMID: 10355763 DOI: 10.1099/0022-1317-80-5-1167] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The crystal structure coordinates of the hepatitis C virus NS3 protease (HCVpro) were used to develop an homology model of the dengue 2 virus NS3 protease (DEN2pro). The amino acid sequence of DEN2pro accommodates the same alpha-helices, beta-sheets and protein-binding domains as its HCVpro counterpart, but the model predicts a number of significant differences for DEN2pro and its interactions with substrates and cofactor. Whereas HCVpro contains a Zn2+-binding site, there is no equivalent metal-binding motif in DEN2pro. It is possible that the structural role played by the zinc ion may be provided by a salt bridge between Glu93 and Lys145. The two-component viral protease comprises NS3 and a virus-encoded cofactor, NS4A for HCV and NS2B for DEN2. Previous studies have identified a central 40 amino acid cofactor domain of the dengue virus NS2B that is required for protease activity. Modelling of the putative interactions between DEN2pro and its cofactor suggests that a 12 amino acid hydrophobic region within this sequence (70GSSPILSITISE81) may associate directly with NS3. Modelling also suggests that the substrate binds in an extended conformation to the solvent-exposed surface of the protease, with a P1-binding site that is significantly different from its HCV counterpart. The model described in this study not only reveals unique features of the flavivirus protease but also provides a structural basis for both cofactor and substrate binding that should prove useful in the early design and development of inhibitors.
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Leung D. Apropos telemedicine. THE CANADIAN VETERINARY JOURNAL = LA REVUE VETERINAIRE CANADIENNE 1999; 40:318-20. [PMID: 10340090 PMCID: PMC1539803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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172
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Leu AJ, Pfammatter T, Schneider E, Enzler M, Leung D, Hoffmann U. Spontaneous reversibility of early reobstruction following percutaneous transluminal angioplasty. VASA 1999; 28:46-9. [PMID: 10191707 DOI: 10.1024/0301-1526.28.1.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Early reocclusion and late restenosis are well-known problems after percutaneous transluminal angioplasty (PTA). We report here on a phenomenon not described so far in two patients with peripheral arterial occlusive disease who had PTA of the common iliac and the superficial femoral artery, respectively. Both had a good hemodynamic and clinical initial result. However, within two days after PTA symptomatic reobstruction occurred documented by noninvasive measurements. Noteworthy, this reobstruction was spontaneously reversible within days. The possible pathomechanism is discussed.
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173
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Lewis JJ, Leung D, Casper ES, Woodruff J, Hajdu SI, Brennan MF. Multifactorial analysis of long-term follow-up (more than 5 years) of primary extremity sarcoma. ARCHIVES OF SURGERY (CHICAGO, ILL. : 1960) 1999; 134:190-4. [PMID: 10025462 DOI: 10.1001/archsurg.134.2.190] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND The majority of survival studies in patients with extremity soft tissue sarcoma have focused on early recurrence and mortality. There are few data addressing long-term follow-up and survival. OBJECTIVE To analyze survival and recurrence in patients with extremity soft tissue sarcoma who survive for more than 5 years. METHODS Patients who underwent treatment for primary tumors (July 1982 to July 1994) and were followed up for more than 5 years were the subject of study. Disease-specific and disease-free survival were determined actuarially. Significance was evaluated using log-rank testing for univariate analysis and Cox model stepwise regression for multivariate analysis. RESULTS A total of 495 patients with primary extremity tumors were treated before July 1989 and eligible for 5-year follow-up. Of these, 282 have been followed up for more than 5 years (median follow-up, 84.4 months). Actuarial disease-specific survival of patients who survive for longer than 5 years was 79%+/-7% (+/-SEM) at 10 years, and of those who were metastasis free at 5 years was 91%+/-4% at 10 years. On univariate analysis, post-5-year disease-specific survival was influenced by positive microscopic margin and initial tumor size of 5 cm or greater. On multivariate analysis, post-5-year disease-specific survival was influenced only by positive margins. CONCLUSIONS Based on these analyses, 21% of patients with primary extremity sarcoma who survive for 5 years will die of disease within 5 years. Even of those who are metastasis free at 5 years, 9% will die of disease within 5 years. In contrast to early mortality, tumor grade has no influence on post-5-year prognosis. Patients with positive microscopic margins are at risk for post-5-year disease-specific mortality and therefore require long-term follow-up and consideration for investigational therapy.
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174
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Kim SH, Karpeh MS, Klimstra DS, Leung D, Brennan MF. Effect of microscopic resection line disease on gastric cancer survival. J Gastrointest Surg 1999; 3:24-33. [PMID: 10457320 DOI: 10.1016/s1091-255x(99)80004-3] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To study the effect of residual microscopic resection line disease in gastric cancer, we compared 47 patients with positive margins to 572 patients who underwent R0 resections using a multivariate analysis of factors affecting outcome. Although the presence of positive margins was a significant and independent predictor of outcome for the entire group (N = 619), this factor lost significance in patients who had undergone D2 or D3 lymph node dissections (N = 466). Subset analysis within the D2/D3 group determined that this finding was limited mainly to those patients with.5 positive nodes (N = 189). The survival of patients who had </=5 positive nodes (N = 277) was significantly worsened by a microscopically involved margin. Supporting this observation, intraoperative reexcision of microscopic disease based on frozen section analysis resulted in a significant improvement in overall survival in patients with </=5 positive nodes but not in those with >5 positive nodes. We conclude that the significance of a positive microscopic margin in gastric cancer is dependent on the extent of disease. This factor is not predictive of outcome in patients who have undergone complete gross resection and have pathologically proved advanced nodal disease. Thus the goal in these cases should be an R0 resection when feasible but with the realization that the presence of >/=5 positive nodes (N2 disease according to the 1997 American Joint Committee on Cancer criteria) will mainly determine outcome and not microscopic residual cancer at the margin.
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Yang K, Edelmann W, Fan K, Lau K, Leung D, Newmark H, Kucherlapati R, Lipkin M. Dietary modulation of carcinoma development in a mouse model for human familial adenomatous polyposis. Cancer Res 1998; 58:5713-7. [PMID: 9865728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Familial adenomatous polyposis (FAP) is caused by a dominant mutation in the adenomatous polyposis coli (APC) gene. Individuals with FAP progressively develop adenomas and carcinomas of the colon and rectum. We developed a mouse model for this disorder by genetically modifying the Apc gene. The resulting mice Apc1638 progressively develop neoplasms in the colon and remainder of the gastrointestinal tract. In this study when Apc1638 mice were fed a Western-style diet, they developed an increased incidence of the end point of carcinomas and number of invasive tumors. The findings therefore demonstrated dietary modulation of carcinoma incidence in mice with a targeted mutation providing a model for the study of gene-environment interactions in cancer.
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