How unsaturated fatty acids and plant stanols affect sterols plasma level and cellular membranes? Review on model studies involving the Langmuir monolayer technique

The Langmuir monolayer technique has long been known for its usefulness to study the interaction between molecules and mimic cellular membranes to understand the mechanism of action of biologically relevant molecules. In this review we summarize the results that provided insight into the potential mechanism for lowering the plasma level of cholesterol by hypocholesterolemic substances (unsaturated fatty acids (UFAs) and phytocompounds) - in the aspect of prevention of atherosclerosis - and their effects on model biomembranes. The results on UFAs/cholesterol (oxysterols) interactions indicate that these systems are miscible and strongly interacting, contrary to immiscible systems containing saturated fatty acids. Lowering of cholesterol plasma level by UFAs was attributed to the strong affinity between UFAs and sterols, resulting in the formation of high stability complexes, in which sterols were bound and eliminated from the body. Studies on the effect of UFAs and plant sterols/stanols on simplified biomembranes (modeled as cholesterol/DPPC system) indicated that the studied hypocholesterolemic substances modify the biophysical properties of model membrane, affecting its fluidity and interactions between membrane components. Both UFAs and plant sterols/stanols were found to loosen interactions between DPPC and cholesterol and decrease membrane rigidity caused by the excess cholesterol in biomembrane, thus compensating strong condensing effect of cholesterol and restoring proper membrane fluidity, which is of utmost importance for normal cells functioning. The agreement between model - in vitro - studies and biological results prove the usefulness of the Langmuir monolayer technique, which helps in understanding the mode of action of biologically relevant substances.

[Hypopharynx and larynx basaloid squamous carcinoma: our experience with 6 cases]

INTRODUCTION

Basaloid squamous carcinoma (BSC) of the head and neck is an uncommon, recently described variant of epidermoid carcinoma. BSC appears biologically with a greater propensity to local aggressiveness and metastatic potential than the conventional type.

OBJECTIVES

To determine the incidence of BSC of the larynx and hypopharynx in our area, and to evaluate its behavior and prognosis.

PATIENTS & METHODS

272 cases of squamous carcinoma of the larynx and hypopharynx were reviewed and 6 diagnosis of BSC were made, corresponding to 6 tumors in 5 patients. Their clinical records were analyzed. An immunohistochemical study was performed, including antibodies against cytokeratins (CK 7, CK 8, CK 19, CK 20, CK 1, 10, 5, 14, y CK 10), epithelial markers (EMA, CEA, Ber-EP4), vimentin and three neuroendocrine markers: neuron-specific enolase, chromogranin and synaptophisin. Bcl-2 expression was also investigated.

RESULTS

Most tumors were supraglottic. 5 out of 6 tumors were clinically benign, without any metastases or recurrence after exclusive surgical resection and a follow-up ranging 42 to 142 months. We detected a trend toward a primitive pattern of keratin expression. All tumors were stained with EMA and CEA MoAbs, but we could not find Ber-EP4 nor endocrine markers staining in any of them. However, BCL-2 expression was widely found in 4 out of 5 tumors immunostained.

CONCLUSION

It seems to be a progressive dedifferentiation of the basaloid cell component, probably a subpopulation with more primitive features responsible of the aggressiveness reported in the literature. However, the surprising good prognosis in most of our cases makes necessary more studies and wider series to confirm our data.

Juvenile neutrophilic eccrine hidradenitis: a vasculitis-like plantar dermatosis

Neutrophilic eccrine hidradenitis is a variety of neutrophilic dermatosis described in patients with different neoplasms, most often leukaemia, and different chemotherapy regimens. It is characterised by neutrophilic infiltration of the eccrine coils of sweat glands. Recently it has been described in healthy juveniles, involving primarily the soles of the feet. We describe five new cases of juvenile neutrophilic eccrine hidradenitis all showing a good prognosis or a self-limiting course.

[Primary segmental sclerosing cholangitis associated with Sjögren's syndrome]

We report the case of a patient with primary sclerosing cholangitis associated with Sjögren's syndrome and Raynaud's phenomenon, an uncommon association. The presence of periportal lymph nodes with features similar to those described in autoimmune diseases suggests an immune pathogenesis of the disease. The localized and segmentary involvement of the common duct is also an uncommon finding. The pathogenetic and therapeutic aspects are discussed.