RESUMEN
Chrysotile-containing joint compound was commonly used in construction of residential and commercial buildings through the mid 1970s; however, these products have not been manufactured in the United States for more than 30 years. Little is known about actual human exposures to chrysotile fibers that may have resulted from use of chrysotile-containing joint compounds, because few exposure and no health-effects studies have been conducted specifically with these products. Because limited amounts of historical joint compounds are available (and the stability or representativeness of aged products is suspect), it is currently impossible to conduct meaningful studies to better understand the nature and magnitude of potential exposures to chrysotile that may have been associated with historical use of these products. Therefore, to support specific exposure and toxicology research activities, two types of chrysotile-containing joint compounds were produced according to original formulations from the late 1960s. To the extent possible, ingredients were the same as those used originally, with many obtained from the original suppliers. The chrysotile used historically in these products was primarily Grade 7RF9 from the Philip Carey mine. Because this mine is closed, a suitable alternate was identified by comparing the sizes and mineral composition of asbestos structures in a sample of what has been represented to be historical joint compound (all of which were chrysotile) to those in samples of three currently commercially available Grade 7 chrysotile products. The re-created materials generally conformed to original product specifications (e.g. viscosity, workability, crack resistance), indicating that these materials are sufficiently representative of the original products to support research activities.
Asunto(s)
Asbestos Serpentinas/efectos adversos , Materiales de Construcción/efectos adversos , Exposición por Inhalación , Exposición Profesional , Asbestos Serpentinas/química , Asbestos Serpentinas/historia , Materiales de Construcción/análisis , Materiales de Construcción/historia , Historia del Siglo XX , Humanos , Ensayo de Materiales , Fibras Minerales , Tamaño de la Partícula , Medición de Riesgo , ViscosidadRESUMEN
The occupational exposure limit of 2.0 microg/m3 for beryllium has been used in the workplace since the late 1940s. In particular, the adequacy of the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) for beryllium has recently come into question. The symposium "Beryllium: Effect on Worker Health" was convened in September 1999, to bring together leading scientists to present and discuss current research activities on beryllium exposure and chronic beryllium disease (CBD). One of the key questions to be resolved at the symposium was, "Is there a sufficient understanding of exposure and the cause of CBD that would allow us to develop a TLV that we believe would prevent disease?" Seven scientists presented information regarding the current understanding of the disease, possible causes, and ongoing research. The topics were (1) biomonitoring approaches and their relationship with clinical effects, (2) historical and current exposure assessments, (3) sampling methods and aerosol characterization, and (4) epidemiology. Six basic hypotheses regarding the relationship between exposure to beryllium and CBD were generated from the information presented at the symposium. The six hypotheses that are related to issues such as beryllium form, particle size, industrial hygiene practices, extrapulmonary routes of exposure, and genetic susceptibility also appear to be the focus of ongoing and likely future research initiatives. This article summarizes both the presentations made at the meeting and the hypotheses generated. It is expected that an understanding of these issues should explain the inconsistent dose-response relationship observed between exposure and CBD. The ongoing and planned research is anticipated to provide sufficient data within two to three years to develop one or more scientifically sound TLVs for the different chemical forms of beryllium.
Asunto(s)
Contaminantes Ocupacionales del Aire/normas , Beriliosis/prevención & control , Berilio/efectos adversos , Monitoreo del Ambiente/normas , Concentración Máxima Admisible , Contaminantes Ocupacionales del Aire/efectos adversos , Contaminantes Ocupacionales del Aire/análisis , Beriliosis/epidemiología , Beriliosis/fisiopatología , Berilio/análisis , Monitoreo del Ambiente/métodos , Monitoreo Epidemiológico , Humanos , Hipersensibilidad/epidemiología , Hipersensibilidad/etiología , Hipersensibilidad/fisiopatología , Estados UnidosRESUMEN
BACKGROUND: Investigators speculate that hereditary thrombotic disease coupled with acquired factors account for a large number of pulmonary thromboemboli. Clinical correlation between genetic and acquired factors with fatal pulmonary thromboemboli has not been extensively studied. METHODS: Archival autopsy material was obtained from patients who died of or with pulmonary emboli for whom confirmed autopsy results were available. Polymerase chain reaction-restriction fragment length polymorphism analysis was performed for factor V Leiden and factor II/20210A allele. Retrospective chart review was performed to determine the presence or absence of acquired factors that can predispose to pulmonary thromboemboli. RESULTS: Two of 36 patients (5.5%) were heterozygous for factor V Leiden. No patients had detected abnormalities for factor II/20210A allele. Eight patients (22.2%) had a malignancy present, one of whom was heterozygous for factor V Leiden. Fourteen patients (38.8%) had recent major surgery or were immobilized. CONCLUSIONS: The incidence of factor V Leiden and factor II/20210A allele in patients with fatal pulmonary thromboemboli is not greater than published results of the incidence of these factors in the general population. Recognized acquired factors such as malignancy, recent surgery, and immobilization are frequently present in these patients. Our results suggest that genetic profiling of thrombotic disease will not replace clinical vigilance in reducing the risk for death from pulmonary thromboemboli.
Asunto(s)
Factor V/genética , Protrombina/genética , Embolia Pulmonar/genética , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inmovilización , Masculino , Persona de Mediana Edad , Neoplasias/etiología , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Embolia Pulmonar/etiología , Embolia Pulmonar/cirugía , Estudios RetrospectivosRESUMEN
OBJECTIVE: Our purpose was to evaluate the ability of the Papanicolaou smear to identify bacterial vaginosis in comparison with the Amsel clinical criteria. STUDY DESIGN: We retrospectively identified 159 pregnant women screened for bacterial vaginosis with the Amsel criteria who had a contemporaneous Papanicolaou smear and negative results on screening for Chlamydia trachomatis and Neisseria gonorrhoeae. Bacterial vaginosis was identified in 45 women. We used the McNemar chi(2) test to determine discrepancies between the two screening methods for the detection of bacterial vaginosis. RESULTS: Compared with the Amsel criteria, the sensitivity and specificity of the Papanicolaou smear for yielding a diagnosis of bacterial vaginosis were 49% (95% confidence interval, 36%-64%) and 93% (95% confidence interval, 86%-97%), respectively, with a positive predictive value of 73% and a negative predictive value of 82%. The detection of bacterial vaginosis by Papanicolaou smear was significantly different from that by Amsel criteria (P =. 01). CONCLUSION: The Papanicolaou smear is not a reliable screening test for bacterial vaginosis during pregnancy.
Asunto(s)
Prueba de Papanicolaou , Complicaciones Infecciosas del Embarazo/microbiología , Frotis Vaginal , Vaginosis Bacteriana/diagnóstico , Reacciones Falso Negativas , Femenino , Humanos , Embarazo , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Soluble epoxide hydrolase (sEH) is suggested to alter the mode of action and increase the toxic potency of fatty acid epoxides. To characterize the structural features necessary for sEH-dependent epoxy fatty acid toxicity, 75 aliphatic compounds were assayed for cytotoxicity in the presence and absence of sEH. Three groups of aliphatic epoxide-diol pairs were described by their observed differential toxicity. Group I compounds were typified by terminal epoxides whose toxicity was reduced in the presence of sEH. Group II compounds were toxic in either their epoxide or diol form, but toxicity was unaffected by sEH. Group III compounds exhibited sEH-dependent toxicity and were therefore used to investigate the structural elements required for cytotoxicity in this study. The optimal structure for group III compounds appeared to be a fatty acid 18-20 atoms long (e.g., a carbon backbone plus a terminal heteroatom) with an epoxide positioned between C-7 and C-12. In the absence of sEH, replacement of epoxides with a vicinal diol was required for toxicity. While diol stereochemistry was unimportant, vicinal diol-induced toxicity exhibited fewer positional constraints to toxicity than sEH-dependent epoxide toxicity. Tested fatty acids and esters with neither an epoxide nor a vicinal diol were not toxic. These data support the hypothesis that long-chain epoxy fatty acid methyl esters are potential pro-toxins metabolized by sEH to more toxic diols. Furthermore, our results suggest that the endogenous compounds, leukotoxin methyl ester, 9,10(Z)-epoxyoctadec-12(Z)-enoic acid methyl ester, and isoleukotoxin methyl ester, 12, 13(Z)-epoxyoctadec-9(Z)-enoic acid methyl ester, are structurally optimized to elicit the observed effect.
Asunto(s)
Epóxido Hidrolasas/fisiología , Compuestos Epoxi/toxicidad , Exotoxinas/toxicidad , Ácidos Grasos/toxicidad , Humanos , Relación Estructura-ActividadRESUMEN
Leukotoxin (ltx) and isoleukotoxin (iltx) methyl esters, are metabolites of methyl linoleic acid, an essential fatty acid. They have been associated with acute respiratory distress syndrome. The observed toxicity of ltx and iltx is, in fact, due to the metabolism of the epoxides to their corresponding diols by soluble epoxide hydrolase (sEH). Herein, we demonstrate that ltx/iltx are toxic in a time-dependent manner to human sEH expressing cells with a LT(50) of 10.6 +/- 0.8 h and that ltx and iltx have K(M) of 6.15 +/- 1.0 and 5. 17 +/- 0.56 microM, respectively, and V(max) of 2.67 +/- 0.04 and 1. 86 +/- 0.06 micromol/min/mg, respectively, which can be inhibited by sEH inhibitors. We show that four major metabolites of ltx/iltx are formed in our system, including ltx/iltx free acid, ltxd/iltxd, free acid, and phosphotidylcholine and phosphotidylethanolamine containing the carboxylic acid forms of both ltx/iltx and ltxd/iltxd, but that the only metabolite associated with toxicity is the carboxylic acid form of ltxd/iltxd, suggesting the involvement of cellular esterases. We demonstrate that a serine esterase inhibitor provides some protection from the toxicity of epoxy fatty esters to sEH expressing cells as do intercellular free sulfhydryls, but that this protection is not due to glutathione conjugation. With these data, we have proposed an extension of the metabolic pathway for ltx/iltx in eukaryotic cells.
Asunto(s)
Compuestos Epoxi/metabolismo , Compuestos Epoxi/toxicidad , Ácidos Linoleicos/metabolismo , Ácidos Linoleicos/toxicidad , Animales , Ácidos Carboxílicos/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Epóxido Hidrolasas/antagonistas & inhibidores , Epóxido Hidrolasas/genética , Epóxido Hidrolasas/metabolismo , Esterasas/antagonistas & inhibidores , Esterasas/metabolismo , Glutatión/análogos & derivados , Glutatión/metabolismo , Glutatión/farmacología , Glicerofosfolípidos/metabolismo , Humanos , Inactivación Metabólica , Cinética , Modelos Biológicos , Fluoruro de Fenilmetilsulfonilo/farmacología , Proteínas Recombinantes/antagonistas & inhibidores , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Spodoptera , Compuestos de Sulfhidrilo/antagonistas & inhibidores , Compuestos de Sulfhidrilo/metabolismoRESUMEN
OBJECTIVE: The objective of this study was to review clinical characteristics, histological findings, and surgical treatment of patients with granular cell tumors of the vulva at Hartford Hospital and examine histologic characteristics associated with those cases that recurred. MATERIALS AND METHODS: A retrospective case review of 13 patients diagnosed with granular cell tumors of the vulva at Hartford Hospital from April 1982 through May 1998 was undertaken to compare age, size and location of the lesion, histopathologic features, presenting symptoms, progression of disease, and treatment. RESULTS: Tumor growth patterns were divided into those with confluent expansile growth (nodular) and those that infiltrated the dermis and soft tissue in a haphazard fashion interdigitating with native connective tissue and skin appendages (infiltrative). The advancing edge of the tumors was assessed as having either a "pushing" or an infiltrative border. The advancing edge of the tumor was noted to be irregular and infiltrative in 8 of the 13 cases. The tumor edge in the remaining 5 was pushing and well demarcated. Five of the eight tumors with an infiltrative edge recurred despite the fact that 3 of the 5 cases had negative surgical margins at resection. None of the 5 cases with "pushing" borders developed recurrence. CONCLUSIONS: Although rare, vulvar tumors are the most common variety of granular cell tumors encountered in the female genital tract. Histologic evaluation seems to indicate that patients are more likely to have a recurrence if an infiltrative growth pattern is present at the advancing edge of the granular cell tumor even with negative margins at resection. An appropriate management strategy may be to recommend reexcision of "infiltrative border" lesions rather than clinical observation alone.
Asunto(s)
Tumor de Células Granulares/patología , Recurrencia Local de Neoplasia , Neoplasias de la Vulva/patología , Adulto , Anciano , Femenino , Tumor de Células Granulares/cirugía , Humanos , Persona de Mediana Edad , Invasividad Neoplásica , Estadificación de Neoplasias , Pronóstico , Estudios Retrospectivos , Neoplasias de la Vulva/cirugíaRESUMEN
Naphthalene is metabolized by several cytochrome P-450 (CYP) monooxygenases to 1,2-epoxynaphthalene. However, the subsequent interactions of the epoxide with macromolecules in the cells, and the significance of these interactions to cellular injury, are not well characterized. Additionally, CYP1A1, which can metabolize naphthalene to 1,2-epoxynaphthalene, may be induced by a number of xenobiotics. Yet, the in situ interaction between naphthalene and CYP1A1 alone, without the influence of other xenobiotic metabolizing enzymes, has not been examined. Using a model eukaryotic expression system capable of over-expressing recombinant CYP1A1, we found that naphthalene was toxic to cells expressing CYP1A1 in a dose- (LC50: 0.3 mM) and time-dependent (LT50: 12 h) manner. Naphthalene treatment of CYP1A1-expressing cells resulted in a 47% decrease in cellular glutathione (GSH) levels. Pretreatment with ethyl ester GSH, a GSH analog, protected CYP1A1-expressing cells such that viability was 30% greater than for cells treated with naphthalene alone. Cytotoxicity was strongly correlated (r2: 0.96) with covalent binding of cellular proteins. Alkaline permethylation techniques showed that cysteinyl-SH groups of cellular proteins are a nucleophilic target of the epoxide metabolite. These results suggest that, in the absence of other pathways, naphthalene is modified by CYP1A1 to 1,2-epoxynaphthalene, which subsequently binds cellular sulfhydryl groups on proteins and GSH.
Asunto(s)
Citocromo P-450 CYP1A1/metabolismo , Glutatión/metabolismo , Naftalenos/toxicidad , Spodoptera/efectos de los fármacos , Animales , Baculoviridae , Western Blotting , Línea Celular/efectos de los fármacos , Línea Celular/enzimología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Relación Dosis-Respuesta a Droga , Electroforesis en Gel de Poliacrilamida , Cromatografía de Gases y Espectrometría de Masas , Glutatión/análogos & derivados , Glutatión/farmacología , Naftalenos/antagonistas & inhibidores , Naftalenos/metabolismo , Unión Proteica , Ratas , Proteínas Recombinantes , Spodoptera/citología , Spodoptera/enzimología , Factores de TiempoRESUMEN
Our objective was to determine the impact of a self-medication program on postpartum narcotic use. We retrospectively studied narcotic use in patients who underwent vaginal delivery before and after implementation of a self-medication program in April 1997. Narcotic use was compared between patients who delivered in January 1997 (n = 263) and those who delivered in January 1998 (n = 254). Oral narcotic use was also analyzed with respect to type of vaginal delivery (spontaneous vs. operative), extent of episiotomy or laceration, and use of epidural analgesia during labor. Narcotic use was significantly reduced (p < 0.001) in postpartum patients who participated in the self-medication program. The reduction was consistent despite the type of vaginal delivery or use of epidural analgesia during labor. A more extensive episiotomy or laceration at delivery (fourth-degree episiotomy or vaginal sulcus tear) was associated with an increase in narcotic use, although there was still a statistically significant decrease in use in patients in the self-medication program. A significant reduction in postpartum narcotic use may be achieved through implementation of a self-medication program. As a result, substantial benefits are potentially gained by both the patients and the nursing staff.
Asunto(s)
Narcóticos/administración & dosificación , Dolor/tratamiento farmacológico , Educación del Paciente como Asunto/organización & administración , Trastornos Puerperales/tratamiento farmacológico , Autoadministración/métodos , Administración Oral , Adulto , Connecticut , Femenino , Humanos , Dolor/etiología , Satisfacción del Paciente , Evaluación de Programas y Proyectos de Salud , Estudios RetrospectivosRESUMEN
The soluble epoxide hydrolase (sEH) plays a significant role in the biosynthesis of inflammation mediators as well as xenobiotic transformations. Herein, we report the discovery of substituted ureas and carbamates as potent inhibitors of sEH. Some of these selective, competitive tight-binding inhibitors with nanomolar K(i) values interacted stoichiometrically with the homogenous recombinant murine and human sEHs. These inhibitors enhance cytotoxicity of trans-stilbene oxide, which is active as the epoxide, but reduce cytotoxicity of leukotoxin, which is activated by epoxide hydrolase to its toxic diol. They also reduce toxicity of leukotoxin in vivo in mice and prevent symptoms suggestive of acute respiratory distress syndrome. These potent inhibitors may be valuable tools for testing hypotheses of involvement of diol and epoxide lipids in chemical mediation in vitro or in vivo systems.
Asunto(s)
Carbamatos/farmacología , Inhibidores Enzimáticos/farmacología , Epóxido Hidrolasas/antagonistas & inhibidores , Urea/análogos & derivados , Urea/farmacología , Animales , Sitios de Unión , Carbamatos/síntesis química , Carbamatos/química , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Epóxido Hidrolasas/química , Humanos , Cinética , Ratones , Proteínas Recombinantes/antagonistas & inhibidores , Relación Estructura-Actividad , Urea/síntesis química , Urea/químicaRESUMEN
The expression of surface antigen CD69 in immune response cells is typically associated with the early stage(s) of cell activation, with maximal expression levels within 4 h of appropriate antigenic or mitogenic stimulation, and maintenance of these high expression levels for 18-24 h. The expression profiles of CD69 in human peripheral blood mononuclear cells (PBMC) cultured with actinomycin D prior to mitogenic stimulation were evaluated by direct immunofluorescence using flow cytometry. Pretreatment of PBMC suspensions with low, non-toxic levels of actinomycin D stimulated CD3+ T-lymphocytes to express CD69 in a concentration-dependent manner. Furthermore, CD4+ T-lymphocytes were the primary cells responding in this fashion. Secondary mitogenic stimulation following antibiotic treatment potentiated cellular CD69 expression in these assays. CD69 expression was profoundly suppressed with in vitro actinomycin D concentrations >/=1-2 microg/ml, presumably by interference with cellular transcription/translation mechanisms. Parallel thymidine incorporation assays indicated that actinomycin D effectively inhibited thymidine uptake in a concentration-dependent manner, with complete inhibition at >/=0.1 microg/ml. The evaluation of cell cycling dynamics following antibiotic treatment, with and without secondary mitogen stimulation, indicated no substantial changes in DNA synthesis over controls. The diversity of these responses suggests that expression of CD69 may not solely reflect mitogenic activation status but may, under some conditions, result from induced cellular stress.
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Antígenos CD/biosíntesis , Antígenos de Diferenciación de Linfocitos T/biosíntesis , Dactinomicina/farmacología , Linfocitos T/efectos de los fármacos , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Ciclo Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Técnica del Anticuerpo Fluorescente , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/inmunología , Humanos , Lectinas Tipo C , Mitógenos/farmacología , Linfocitos T/inmunologíaAsunto(s)
Ácido Linoleico/metabolismo , Ácido Linoleico/toxicidad , Animales , Epóxido Hidrolasas/metabolismo , Compuestos Epoxi/metabolismo , Compuestos Epoxi/toxicidad , Glutatión/metabolismo , Humanos , Ácido Linoleico/química , Ácidos Linoleicos/biosíntesis , Ácidos Linoleicos/toxicidad , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Ácidos Oléicos/biosíntesis , Ácidos Oléicos/metabolismo , Ácidos Oléicos/toxicidad , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Flavopiridol is a novel semisynthetic flavone derivative of the alkaloid rohitukine. Flavopiridol is known to inhibit potently the activity of multiple cyclin-dependent kinases. We have assessed its effects on normal and malignant cells in preclinical animal models of localized and disseminated human hematopoietic neoplasms. Flavopiridol, when administered as daily bolus intravenous (IV) injections, produced selective apoptosis of cells in the thymus, spleen, and lymph nodes, resulting in atrophy of these organs. With the exception of the intestinal crypts, apoptosis or tissue damage was absent in all other organs investigated (kidneys, liver, lungs, bone/bone marrow, muscle, and heart). Flavopiridol had a marked apoptotic effect documented by DNA nick-end labeling, or DNA agarose gels in xenografts of human hematopoietic tumors HL-60, SUDHL-4, and Nalm/6. After treatment with 7.5 mg/kg flavopiridol bolus IV or intraperitoneal on each of 5 consecutive days, 11 out of 12 advanced stage subcutaneous (s.c.) human HL-60 xenografts underwent complete regressions, and animals remained disease-free several months after one course of flavopiridol treatment. SUDHL-4 s.c. lymphomas treated with flavopiridol at 7.5 mg/kg bolus IV for 5 days underwent either major (two out of eight mice) or complete (four out of eight mice) regression, with two animals remaining disease-free for more than 60 days. The overall growth delay was 73.2%. The acquired immunodeficiency syndrome-associated lymphoma AS283 showed no significant response when flavopiridol was used in advanced s.c. tumors, but when treatment was initiated in early stages, there was a complete regression of the early tumors, and a significant overall growth delay (>84%). When flavopiridol was used in severe combined immunodeficient mice bearing disseminated human acute lymphoblastic leukemia Nalm/6 cells, there was 15-day prolongation in survival (P = .0089). We conclude that flavopiridol greatly influences apoptosis in both normal and malignant hematopoietic tissues. This activity was manifested in our study as a potent antileukemia or antilymphoma effect in human tumor xenografts, which was dose and schedule dependent. These findings provide compelling evidence for the use of flavopiridol in human hematologic malignancies.
Asunto(s)
Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Flavonoides/farmacología , Flavonoides/uso terapéutico , Inhibidores de Crecimiento/farmacología , Inhibidores de Crecimiento/uso terapéutico , Terapia de Inmunosupresión , Leucemia/patología , Linfocitos/efectos de los fármacos , Linfoma/patología , Neoplasias Experimentales/patología , Piperidinas/farmacología , Piperidinas/uso terapéutico , Animales , Células HL-60 , Humanos , Leucemia/tratamiento farmacológico , Linfocitos/patología , Linfoma/tratamiento farmacológico , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Neoplasias Experimentales/tratamiento farmacológicoRESUMEN
Some ellipticine derivative salts, including 9-chloro-2-methylellipticinium (CME), have been found to have a marked selectivity against all eight brain tumor cell lines of the U.S. National Cancer Institute's disease-oriented in vitro screen. We initiated in vivo antitumor studies to explore the feasibility for further development of this class of compounds. We found that CME was extremely toxic to nude mice when given i.p. at a dose of 25 mg/kg for 3 consecutive days. Animals treated by this route experienced an increase in hepatic transaminases and histopathological changes in the liver, compatible with mitochondrial damage. In contrast, when the portal circulation was bypassed and the same dose of CME was given i.v., animals tolerated daily bolus injections for 5 consecutive days. This 5-day i.v. bolus schedule had consistent antitumor activity, with 28.1% growth delay on s.c. implanted human U251 gliomas. When the potentially high peaks of CME in the portal circulation were avoided by using a 3-day continuous infusion with osmotic minipumps implanted i.p. to release 3.4 mg kg(-1) h(-1) or 6.6 mg kg(-1) h(-1) CME, there were only modest increases in liver enzymes and leukopenia, but no meaningful antitumor activity was observed. In contrast, continuous infusion in the s.c. space was well tolerated and was accompanied by a demonstrable growth delay in s.c. U251 human gliomas of 37.8%. When CME was used in conjunction with carmustine, etoposide or cisplatin, no synergistic activities were observed, but additive effects were demonstrated. Our pharmacokinetic and disposition studies with CME argue against the notion that large and invasive tumors in the brain lack blood-brain barrier features. When CME was used in animals bearing orthotopically implanted U251 gliomas in the brain of nude mice, the survival of the treated animals was not better than vehicle controls, and the addition of CME to carmustine therapy did not improve the survival of those animals treated with carmustine alone. We conclude that, in spite of its marked cytotoxicity in vitro on a variety of human brain tumor cell lines, including U251 glioma cells, CME has a modest antitumor effect on extracranially implanted U251 glioma tumors, and no beneficial effect in animals bearing the same U251 tumor in the brain, owing to a poor penetration into the brain parenchyma.
Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Elipticinas/uso terapéutico , Glioma/tratamiento farmacológico , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/toxicidad , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Barrera Hematoencefálica/fisiología , Neoplasias Encefálicas/mortalidad , Carmustina/administración & dosificación , Enfermedad Hepática Inducida por Sustancias y Drogas , Cisplatino/administración & dosificación , Ensayos de Selección de Medicamentos Antitumorales , Elipticinas/administración & dosificación , Elipticinas/farmacocinética , Elipticinas/toxicidad , Etopósido/administración & dosificación , Estudios de Factibilidad , Femenino , Glioma/mortalidad , Humanos , Inyecciones Intraperitoneales , Inyecciones Intravenosas , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Tasa de Supervivencia , Trasplante HeterólogoRESUMEN
Leukotoxin is a linoleic acic oxide produced by leukocytes and has been associated with the multiple organ failure and adult respiratory distress syndrome seen in some severe burn patients. Leukotoxin has been reported to be toxic when injected into animals intravenously. Herein, we report that this lipid is not directly cytotoxic in at least two in vitro systems. Using a baculovirus expression system we demonstrate that leukotoxin is only cytotoxic in the presence of epoxide hydrolases. In addition, it is the diol metabolite that proves toxic to pulmonary alveolar epithelial cells, suggesting a critical role for the diol in leukotoxin-associated respiratory disease. In vivo data also support the toxicity of leukotoxin diol. For the first time we demonstrate that soluble epoxide hydrolase can bioactivate epoxides to diols that are apparently cytotoxic. Thus leukotoxin should be regarded as a protoxin corresponding to the more toxic diol. This clearly has implications for designing new clinical interventions.
Asunto(s)
Citotoxinas/toxicidad , Epóxido Hidrolasas/metabolismo , Ácidos Linoleicos/toxicidad , Animales , Baculoviridae , Línea Celular , Permeabilidad de la Membrana Celular , Células Cultivadas , Citotoxinas/metabolismo , Conductividad Eléctrica , Células Epiteliales , Epitelio/fisiología , Humanos , Uniones Intercelulares , Transporte Iónico , Ácidos Linoleicos/metabolismo , Masculino , Ratones , Alveolos Pulmonares/citología , Alveolos Pulmonares/fisiología , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/metabolismo , SpodopteraRESUMEN
The spontaneous regression of melanoma in Sinclair miniature swine involves the replacement of tumours by pigmented cells, hitherto interpreted as pigment-laden macrophages (PLMs). We hypothesized that these residual cells are terminally differentiated melanoma cells, not monocyte-derived macrophages. Swine melanoma explants with no regression were transplanted into severe combined immunodeficient (SCID) mice. Harvested transplant sites were examined by routine light and electron microscopy techniques. Paraffin sections were also stained with Hoeschst dye and examined by fluorescence microscopy. All but one site had completely regressed and were replaced by PLM-like cells. Hoeschst staining indicated they were of swine, not mouse, origin. The ultrastructural features of the single, partially regressed lesion demonstrated many premelanosomes in these cells. We conclude that tumour differentiation is an important mechanism of regression in the Sinclair swine melanoma model.
Asunto(s)
Melanoma/patología , Regresión Neoplásica Espontánea , Neoplasias Cutáneas/patología , Animales , Bisbenzimidazol , Diferenciación Celular/fisiología , Modelos Animales de Enfermedad , Humanos , Masculino , Ratones , Ratones SCID , Microscopía Electrónica , Trasplante de Neoplasias , Pigmentación , Coloración y Etiquetado/métodos , Porcinos , Trasplante HeterólogoRESUMEN
Selectively-bred Sinclair miniature swine exhibit a high incidence of congenital malignant melanoma which either proves fatal (10-15% of tumor-bearing piglets) or spontaneously regresses with a biphasic immunological phenomenon (85-90%) and no recurrence of malignancy. Mononuclear leukocytes were isolated from cutaneous melanomas and peripheral blood specimens collected from melanomatous (tumor-bearing) Sinclair swine during second-phase regression, and from peripheral blood specimens collected from non-melanomatous (tumor-free) Sinclair swine and control Hanford swine. Leukocyte identities were determined with single- and dual-parameter indirect immunofluorescence assays via flow cytometry. Assays for the specific surface antigens CD45, CD2, CD4, CD8, CD1, MHC class II, and N1 were employed to develop immunophenotypic profiles within the gated lymphocyte clusters from each TIL and PBL suspension. Significantly more CD8+ T-lymphocytes were identified in TIL suspensions than in peripheral blood leukocyte (PBL) suspensions (P < and = 0.05), regardless of breed or tumor status. Conversely, PBL suspensions contained significantly higher percentages of CD4+ T-lymphocytes than the levels found in TIL suspensions (P < and = 0.05). Virtually all TIL were MHC class II+, whereas the percentages of PBL expressing this antigen were markedly lower (P < and = 0.05). The percentages of T-lymphocytes co-expressing CD4 and CD8, a normal subset unique to swine, were generally consistent in all TIL and PBL suspensions examined. The results of this study have firmly established the immunophenotypic identities of cells associated with the second-phase regression phenomenon of this melanoma and have identified specific variations in the leukocyte profiles of the respective TIL and PBL suspensions.
Asunto(s)
Subgrupos Linfocitarios/clasificación , Linfocitos Infiltrantes de Tumor/clasificación , Melanoma/inmunología , Melanoma/veterinaria , Neoplasias Cutáneas/inmunología , Neoplasias Cutáneas/veterinaria , Animales , Separación Celular/veterinaria , Inmunofenotipificación/veterinaria , Subgrupos Linfocitarios/inmunología , Linfocitos Infiltrantes de Tumor/inmunología , Regresión Neoplásica Espontánea , Porcinos , Porcinos Enanos , Subgrupos de Linfocitos T/clasificaciónRESUMEN
A new method for experimentally analyzing the role of enzymes involved in metabolizing mutagenic, carcinogenic, or cytotoxic chemicals is described. Spodoptera fugiperda (SF-21) cells infected with recombinant baculoviruses are used for high level expression of one or more cloned enzymes. The ability of these enzymes to prevent or enhance the toxicity of drugs and xenobiotics is then measured in situ. Initial parameters for the system were developed and optimized using baculoviruses engineered for expression of the mouse soluble epoxide hydrolase (msEH, EC 3.3.2.3) or the rat cytochrome P4501A1. SF-21 cells expressing msEH were resistant to trans-stilbene oxide toxicity as well as several other toxic epoxides including: cis-stilbene oxide, 1,2,7,8-diepoxyoctane, allylbenzene oxide, and estragole oxide. The msEH markedly reduced DNA and protein adduct formation in SF-21 cells exposed to [3H]allylbenzene oxide or [3H]estragole oxide. On the other hand, 9,10-epoxyoctadecanoic acid and methyl 9,10-epoxyoctadecanoate were toxic only to cells expressing sEH, suggesting that the corresponding fatty acid diols were cytotoxic. This was confirmed by showing that chemically synthesized diols of these fatty acid epoxides were toxic to control SF-21 cells at the same concentration as were the epoxides to cells expressing sEH. A recombinant baculovirus containing a chimeric cDNA formed between the rat P4501A1 and the yeast NADPH-P450 reductase was also constructed and expressed in this system. A model compound, naphthalene, was toxic to SF-21 infected with the rat P4501A1/reductase chimeric co-infecting SF-21 cells with either a human or a rat microsomal EH virus along with P4501A1/reductase virus. These results demonstrate the usefulness of this new system for experimentally analyzing the role of enzymes hypothesized to metabolize endogenous and exogenous chemicals of human health concern.
Asunto(s)
Carcinógenos/toxicidad , Sistema Enzimático del Citocromo P-450/metabolismo , Citotoxinas/toxicidad , Epóxido Hidrolasas/metabolismo , Mutágenos/toxicidad , Pruebas de Toxicidad/métodos , Animales , Baculoviridae , Secuencia de Bases , Línea Celular , Supervivencia Celular/efectos de los fármacos , Clonación Molecular , Sistema Enzimático del Citocromo P-450/biosíntesis , Cartilla de ADN , Evaluación Preclínica de Medicamentos/métodos , Resistencia a Medicamentos , Epóxido Hidrolasas/biosíntesis , Humanos , Ratones , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ratas , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/metabolismo , Mapeo Restrictivo , Spodoptera , Relación Estructura-Actividad , Xenobióticos/toxicidadRESUMEN
This chapter documents the success of a 12-month individualized structured language curriculum (LANGUAGE!) provided to middle and high school juvenile offenders (n=45; 43 males; 2 females) enrolled in a rehabilitation program. Although individual students participated in the program for an average of just 22.7 weeks (SD 8.51), they made significant gains (more than three years growth) over this period in written language expression (composition), encoding (spelling), and decoding (isolated word recognition), as documented by standardized literacy measures, moving from standard scores in the 60s and 70s to the 80s and 90s. Gains on the Gray Oral Reading Test (GORT III) were consistent with these measures and well exceeded gains made by a comparison group (n=51; 48 males, 3 females) which included students attending similar rehabilitation programs for a comparable period of time, but these students were not offered the individualized LANGUAGE! curriculum. Details of the LANGUAGE! curriculum and the basis of its success are discussed.