ABSTRACT
Peroxysomicine A1, a novel potential anticancer compound induced cell death in established cell lines and in a primary culture of rat neonatal cardiomyocytes. Non-transformed cells are less sensitive to the compound than transformed cell lines. Fluorescent microscopy of dying cells stained with DNA-specific dyes revealed chromatin condensation and nuclear fragmentation as well as membrane blebbing characteristic of apoptosis. Flow cytometry of cells treated with peroxysomicine A1, demonstrated appearance of cells containing less than 2C DNA, that indicated degradation of nuclear DNA, another hallmark of apoptotic cell death. Z-VAD, a nonspecific caspase inhibitor, prevented DNA fragmentation but not cell death registered by permeabilization of cell outer membrane. Peroxysomicine A1 also inhibited proliferation of various cell lines. Flow cytometry analysis showed significant accumulation of dividing cells in G2/M phases of cell cycle indicating, most likely delay in G2. These results provide initial insight into the mechanisms of action of peroxysomicine A1 and suggest that peroxysomicine A1 is a potent inhibitor of cell proliferation and inducer of apoptosis and may be a useful antineoplastic chemotherapeutic agent.
Subject(s)
Anthracenes/toxicity , Antineoplastic Agents, Phytogenic/toxicity , DNA Fragmentation/drug effects , Amino Acid Chloromethyl Ketones/pharmacology , Caspase Inhibitors , Cell Cycle/drug effects , Cell Survival/drug effects , DNA, Neoplasm/drug effects , Dose-Response Relationship, Drug , Flow Cytometry , HeLa Cells/drug effects , HeLa Cells/pathology , Humans , Jurkat Cells/drug effects , Jurkat Cells/pathologyABSTRACT
Peroxisomicine A(1) (T-514) is a dimeric anthracenone first isolated from the plant Karwinskia humboldtiana. The compound presents a high and selective toxicity toward liver and skin cell cultures and is currently the subject of preclinical studies as an antitumor drug. To date, the molecular basis for its diverse biological effects remains poorly understood. To elucidate its mechanism of action, we studied its interaction with DNA and its effects on human DNA topoisomerases. Practically no interaction with DNA was detected. Peroxisomicine was found to inhibit topoisomerase II but not topoisomerase I. DNA relaxation and decatenation assays indicated that the drug interferes with the catalytic activity of topoisomerase II but does not stimulate DNA cleavage, in contrast to conventional topoisomerase poisons such as etoposide. Two human leukemia cell lines sensitive or resistant to mitoxantrone were used to assess the cytotoxicity of the toxin and its effect on the cell cycle. In both cases, peroxisomicine treatment was associated with a loss of cells from every phase of the cell cycle and was accompanied by a large increase in the sub-G1 region which is characteristic of apoptotic cells. The cell cycle changes were more pronounced with the sensitive HL-60 cells than with the resistant HL-60/MX2 cells (with reduced topoisomerase II activity), in agreement with the cytotoxicity measurements. Treatment of HL-60 cells with T-514 stimulated the cleavage of the poly(ADP-ribose) polymerase by intracellular proteases such as caspase-3. The cytometry and Western blot analyses reveal that peroxisomicine induces apoptosis in leukemia cells. In addition, we characterized a catabolite of peroxisomicine, named T-510R, in the form of a highly stable radical metabolite. The electron spin resonance and mass spectrometry data are consistent with the formation of an anionic semiquinonic radical. The oxidized product T-510R inhibits topoisomerase II with a reduced efficiency compared to the parent toxin and was found to be about 3-4 times less toxic to both the sensitive and resistant leukemia cell lines than T-514. Collectively, the results suggest that topoisomerase II inhibition plays a role in the cytotoxicity of the plant toxin peroxisomicine. Inhibition of topoisomerase II may serve as an inducing signal triggering the apoptotic cell death of leukemia cells exposed to the toxin. The dihydroxyanthracenone unit may represent a useful chemotype for the preparation of topoisomerase II-targeted anticancer agents.
Subject(s)
Anthracenes/metabolism , Anthracenes/toxicity , Antineoplastic Agents, Phytogenic/metabolism , Antineoplastic Agents, Phytogenic/toxicity , Apoptosis/drug effects , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/toxicity , Topoisomerase II Inhibitors , Caspase 3 , Caspases/metabolism , DNA, Neoplasm/metabolism , DNA, Superhelical/metabolism , Drug Resistance, Neoplasm , Electron Spin Resonance Spectroscopy , Enzyme Activation/drug effects , Free Radicals/metabolism , Free Radicals/toxicity , HL-60 Cells/cytology , HL-60 Cells/drug effects , HL-60 Cells/enzymology , Humans , Kinetics , Mitoxantrone/pharmacology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Topoisomerase I InhibitorsABSTRACT
UNLABELLED: The contribution of carcinoembryonic antigen carcinoembryionic antigen for the effective management of colorectal cancer patients remains a controversial issue. The aim of this study is to attempt to get some valid answers to its function in the diagnosis, prognosis, and overall management of colorectal cancer patients. METHODS: A retrospective review of colorectal cancer patients managed and prospectively registered by the authors between 1985 and 1998 was performed. Serum carcinoembryionic antigen levels were determined preoperatively in 209 patients with primary colorectal cancer and postoperatively in 196 patients who had undergone curative resection of their tumors, according to a fixed schedule. A maximum value of 5 ng/ml was accepted as being normal. With the exception of endoscopy, all other diagnostic techniques were only used after an abnormal carcinoembryionic antigen result (a raised value found twice consecutively). RESULTS: carcinoembryionic antigen preoperative values were raised only in 40 percent of patients and were related to disease stage, with the highest values found in patients with Stage IV disease. However, an elevated preoperative carcinoembryionic antigen value had a very marked prognostic importance, with a statistically significant difference in survival curves (Kaplan-Meier); the same was valid for curatively resected patients (Stages I, II, and III) and for Stages II and III patients considered separately. Multivariate analysis using the Cox proportional hazards technique confirmed these results, showing preoperative carcinoembryionic antigen to have an independent prognostic value, with a relative risk of recurrence of 3.74 for patients with raised preoperative carcinoembryonic antigen levels. In postoperative follow-up, carcinoembryionic antigen elevation was found to be a very accurate marker of recurrence (sensitivity, 77 percent; specificity, 98 percent), mainly in liver metastasis (sensitivity, 100 percent), and the best marker of asymptomatic recurrence (63 percent of cases). However, carcinoembryionic antigen's impact on overall survival was negligible because of the poor results of surgical treatment of recurrences. CONCLUSIONS: Preoperative carcinoembryionic antigen is a very important prognostic indicator and should be considered in future trials. Postoperative carcinoembryionic antigen elevation is a very sensitive marker of recurrence and even of asymptomatic recurrence, but its impact on overall survival does not seem to be relevant. Nevertheless, carcinoembryionic antigen should continue to be used in colorectal cancer patients until better methods of diagnosis and treatment of recurrence are developed.
Subject(s)
Carcinoembryonic Antigen/blood , Colorectal Neoplasms/diagnosis , Adult , Aged , Aged, 80 and over , Colorectal Neoplasms/pathology , Humans , Middle Aged , Multivariate Analysis , Neoplasm Staging , Prognosis , Proportional Hazards Models , Retrospective Studies , Sensitivity and SpecificityABSTRACT
Toxicity by Karwinskia humboldtiana, a Rhamnaceae plant, has been assessed in a number of studies. Four dimmeric anthracenones, named T-496, T-514, T-516 and T-544 for their molecular weight, have been isolated from this plant. T-514, in particular, has been shown to be toxic to liver and lung as well as to tumoral cell lines, preferentially to those from liver tumors. For this reason it has been suggested that the toxin could be used as an antineoplastic agent. The present study was performed to characterize the biological activity of T-514 as a potential cytostatic and genotoxic agent. Peripheral blood lymphocytes in culture were used as a test system, where chromosomal aberrations and sister chromatid exchanges were scored in order to evaluate genotoxicity, and mitotic index and cell proliferation kinetics were used as parameters for cytostatic and cytotoxic ability. Genotoxicity to lymphocytes was negative. However, proliferation was affected by the toxin, demonstrating a cytostatic activity independent of genotoxic damage.
Subject(s)
Anthracenes/toxicity , Antineoplastic Agents, Phytogenic/toxicity , Chromosome Aberrations , Cytotoxins/toxicity , Lymphocytes/drug effects , Mutagens/toxicity , Plants, Medicinal , Plants, Toxic , Rhamnus , Adult , Female , Humans , Lymphocytes/ultrastructure , Male , Sister Chromatid ExchangeABSTRACT
Previous acute toxicity studies with 'Tullidora' in mice showed mainly hepatic and pulmonary complications. We tested samples in rat, guinea-pig, hamster and dog, searching for the mechanism of death. A single oral preparation of ripe fruit of Karwinskia humboldtiana was given to all animals. Clinical signs and histopathology were reproduced in all species except dogs. We propose a selective toxicity of the toxins of this fruit to the lungs and liver.
Subject(s)
Plant Poisoning/pathology , Plants, Toxic/chemistry , Animals , Cricetinae , Dogs , Guinea Pigs , Liver/pathology , Lung/pathology , Rats , Species SpecificityABSTRACT
There is no mention in the literature of any analytical method to quantify toxins present in fruits of Karwinskia humboldtiana. It is recommended that thin layer chromatography and densitometry in situ be used, since it is rapid, sensitive and specific. Great variations in the toxin content of fruits collected in different regions of the state of Nuevo Leon (Mexico) were found, showing the importance of applying an analytical method before beginning toxicological experiments.
Subject(s)
Flavonoids , Neurotoxins/isolation & purification , Phenols/isolation & purification , Plants, Toxic/analysis , Polymers/isolation & purification , Toxins, Biological/isolation & purification , Chromatography, Thin Layer , Polyphenols , Toxins, Biological/analysisABSTRACT
To determine the extent of extraneural lesions in buckthorn poisoning, 180 CD1 mice were administered either green or ripe fruit or toxins T-544 or T-514 obtained from the fruit of the plant and were observed over a period of three weeks. Marked weakness, hyporeflexia, hair bristling, ptosis, spinal deformity, weight loss and dypsnea were prominent signs. Mortality in mice given green fruit was 100% at all doses; with toxin T-514 the mortality was 100% at 45 mg/kg. One hundred and sixty-two necropsies were performed and major lesions were found in liver and lung. The pulmonary lesions consisted of progressive vascular congestion and hemorrhage. Alterations in liver consisted of congestion, hemorrhage, hepatocyte degeneration, central zone necrosis and acute diffuse necrosis. Green fruit was more toxic than ripe fruit and T-514 was more active than T-544.
Subject(s)
Plant Poisoning/physiopathology , Plants, Medicinal , Plants, Toxic , Rhamnus , Animals , Female , Male , Mice , Plant Poisoning/pathologyABSTRACT
El cancer del estomago operado es una nueva entidad clinica, cuya incidencia aumenta francamente luego de 10 anos de la operacion inicial, como resultado de esta misma y no de la patologia previa a ella.Su patogenia responderia a las nuevas condiciones creadas en el estomago (reflujo enterogastrico e hipoclorhidria) que, a traves de la modificacion de la flora bacteriana gastrica, determinarian alteraciones en el metabolismo intragastrico de los compuestos nitrogenados y de los acidos biliares, de probables efectos carcinogeneticos. A proposito de 5 observaciones, los autores destacan la dificultad de un diagnostico precoz y la importancia de la endoscopia y biopsia. Preconizan la gastrectomia total, siempre que sea posible.Pero sobre todo acentuan la necesidad de su prevencion a traves de un control endoscopico periodicos de los operados gastricos mas de 10 anos antes, para despistar lesiones precoces
Subject(s)
Middle Aged , Humans , Male , Postoperative Complications , Stomach , Stomach NeoplasmsABSTRACT
El cancer del estomago operado es una nueva entidad clinica, cuya incidencia aumenta francamente luego de 10 anos de la operacion inicial, como resultado de esta misma y no de la patologia previa a ella.Su patogenia responderia a las nuevas condiciones creadas en el estomago (reflujo enterogastrico e hipoclorhidria) que, a traves de la modificacion de la flora bacteriana gastrica, determinarian alteraciones en el metabolismo intragastrico de los compuestos nitrogenados y de los acidos biliares, de probables efectos carcinogeneticos. A proposito de 5 observaciones, los autores destacan la dificultad de un diagnostico precoz y la importancia de la endoscopia y biopsia. Preconizan la gastrectomia total, siempre que sea posible.Pero sobre todo acentuan la necesidad de su prevencion a traves de un control endoscopico periodicos de los operados gastricos mas de 10 anos antes, para despistar lesiones precoces
Subject(s)
Middle Aged , Aged , Humans , Male , Postoperative Complications , Stomach , Stomach NeoplasmsABSTRACT
Se presenta un caso de metastasis esplenica de un adenocarcinoma de colon. Se hace una revision del tema, en especial su frecuencia y la topografia del tumor primitivo
Subject(s)
Adult , Humans , Male , Colonic Neoplasms , Neoplasm Metastasis , Splenic Neoplasms , AdenocarcinomaABSTRACT
Se presenta un caso de tumor desmoide de mama en una portadora de un sindrome de Gardner. Se senala lo excepcional de esta localizacion y se hace una breve revision sobre la enfermedad de Gardner
Subject(s)
Adult , Humans , Female , Breast Neoplasms , Gardner Syndrome , FibromaABSTRACT
Se presenta la experiencia de los autores, sobre la utilidad de la fibrolaparoscopia en cirugia. Se analizan sus indicaciones, resaltando la importancia del procedimiento en el abdomen. Se describe rapidamente la tecnica seguida por los autores, sus ventajas e inconvenientes
Subject(s)
LaparoscopyABSTRACT
Se presenta un caso de aneurisma traumatico de arteria axilar postluxacion de hombro tratado con exito mediante cirurgia. Se revisa su frecuencia y sus principales causas etiologicas
Subject(s)
Axillary Artery , Shoulder DislocationABSTRACT
Las pancreatitis agudas letales (P.A.L.) son anatomo-patologicamente necrotico-hemorragicas. Se acompanan de una mortalidad cercana al 100%. En un intento de obtener una terapeutica mas eficaz que disminuya la elevada mortalidad de estos pacientes, se analizan retrospectivamente las historias clinicas de 22 enfermos tratados por los autores
Subject(s)
PancreatitisABSTRACT
Se analizan retrospectivamente las historias clinicas de 22 pacientes portadores de pancreatitis agudas necrotico-hemorragicas (P.A.N.H.), del punto de vista clinico, anatomo -patologico y terapeutico. Se obtiene asi un criterio terapeutico que parece ser el mas efectivo en el tratamiento de las pancreatitis agudas letales (P.A.L.): el soporte multisistemico precoz, la nocion de sentido evolutivo de la enfermedad pancreatica y la conducta reseccionista temprana cuando la enfermedad esta localizada a la logia
Subject(s)
PancreatitisABSTRACT
La evisceracion terapeutica controlada es un procedimiento consistente en la colocacion de una malla sustitutiva del cierre parietal para conservar la pared en casos de reintervenciones sucesivas, peritonitis hipersepticas, evisceraciones en sujectos en situacion general precaria o en resecciones parietales por sepsis de superficie. Se presentan 23 casos tratados por los autores, destacando la baja incidencia de complicaciones, las indicaciones y tecnica y resultados
Subject(s)
Abdominal Muscles , Surgical Mesh , Wound Healing , PeritonitisABSTRACT
Se publica un nuevo caso de lipoma de intestino delgado, que se presento como una hemorragia digestiva. Se hace una revision del tema, sus caracteres clinicos y anatomo-patologicos
