Surface activity, lipid profiles and their implications in cervical cancer.

BACKGROUND: The profiles of lipids in normal and cancerous tissues may differ revealing information about cancer development and progression. Lipids being surface active, changes in lipid profiles can manifest as altered surface activity profiles. Langmuir monolayers offer a convenient model for evaluating surface activity of biological membranes. AIMS: The aims of this study were to quantify phospholipids and their effects on surface activity of normal and cancerous human cervical tissues as well as to evaluate the role of phosphatidylcholine (PC) and sphingomyelin (SM) in cervical cancer using Langmuir monolayers. METHODS AND MATERIALS: Lipid quantification was done using thin layer chromatography and phosphorus assay. Surface activity was evaluated using Langmuir monolayers. Monolayers were formed on the surface of deionized water by spreading tissue organic phase corresponding to 1 mg of tissue and studying their surface pressure-area isotherms at body temperature. The PC and SM contents of cancerous human cervical tissues were higher than those of the normal human cervical tissues. Role of PC and SM were evaluated by adding varying amounts of these lipids to normal cervical pooled organic phase. Statistical analysis: Student's t-test (p < 0.05) and one-way analysis of variance (ANOVA) was used. RESULTS: Our results reveals that the phosphatidylglycerol level in cancerous cervical tissue was nearly five folds higher than that in normal cervical tissue. Also PC and sphingomyelin SM were found to be the major phospholipid components in cancerous and normal cervical tissues respectively. The addition of either 1.5 microg DPPC or 0.5 microg SM /mg of tissue to the normal organic phase changed its surface activity profile to that of the cancerous tissues. Statistically significant surface activity parameters showed that PC and SM have remarkable roles in shifting the normal cervical lipophilic surface activity towards that of cancerous lipophilic component. CONCLUSION: The Langmuir monolayer technique was sensitive to detect changes in tensiometric profiles of cervical cancers and these could be modulated by alterations in phosphatidylcholine and sphingomyelin levels. Therapeutic strategies may be designed to modulate these tensiometric profiles and lipid constituents of cancerous tissues.

Bioquímica del líquido quístico mamario, III: niveles del factor de crecimiento epidérmico, gonadotrofina coriónica y andrógenos conjugados / Biochemistry of breast cyst fluids, III: levels of NA, K, androgens, epidermal growth factor and human chorionic gonadotropin

En la última década se ha implementado una serie de análisis bioquímicos que permiten identificar varios tipos de líquidos quísticos (LQs). En el presente trabajo se confirma la presencia de polipéptidos y esteroides conjugados -como el factor de crecimiento epidérmico (FCE), el sulfato de dehidroepiandrosterona (S-DHEA) y el androstano-3Ó, 17ß-diol glucurónido (3Ó-Adiol G)- a veces en concentraciones muy elevadas con respecto a los niveles encontrados simultáneamente en el plasma circulante. Como contraste, la concentración del cortisol apenas alcanza a un 20 por ciento del normalmente hallado en el plasma. Se demuestra además que la concentración intraquística del 3Ó-Adiol G se correlaciona positiva y significativamente con la del S-DHEA (r = 0,8744, p < 0,0001) y con el FCE (r = 0,8949, p < 0,0001), con amplia variabilidad en los resultados. Se establece también una correlación negativa entre el 3Ó-Adiol G y el cociente Na/K (r = - 0,6592, p = 0,0001). Por último, se determinan los niveles de la gonadotrofina coriónica (hCG), utilizando un sistema automatizado de quimioluminiscencia, demostrándose que esta glicoproteína se encuentra en cantidades determinables (> 1,1 mUI/ml) en el 73,8 por ciento de los LQs analizados. En el 57,4 por ciento los niveles superan a los encontrados normalmente en el plasma que oscilan entre < 1,1 mUl/ml y 5,5 mUl/ml. En un 4,9 por ciento las concentraciones resultan significativamente elevadas, alcanzando hasta las 1.000 mUl/ml. Se demuestra una correlación negativa con alta significación estadística entre los valores normalizados de la hCG con los niveles del S-DHEA, del 3Ó-Adiol G y del FCE y una correlación positiva con el cociente NA/K. Se discute la posibilidad de que el FCE, los esteroides conjugados y la hCG puedan ser sintetizados de novo en el tejido epitelial que recubre las paredes del quiste