Clinical aggression of prolactinomas: correlations with invasion and recurrence.

Some hypophyseal adenomas are discrete, well-marked lesions, which can be curatively removed by surgical resection, while others seem aggressive, invasive, recidive-prone, most often progressing in spite of any pharmacological, surgical or radiotherapeutical interventions. There is also a great variability within the incidence of aggression and invasion among the various types of hypophyseal immunotypes. Despite their well-differentiated nature and their "benign" constitution, an important number of hypophyseal tumors will be surely invasive within the sclerous, osseous and neural structures. Because the aggressive behavior of invasive adenomas is generally resolved by surgical treatment, this aspect of their biology does not perfectly reflect within their histopathological aspect. In fact, the invasive tumors with local extreme aggression are most often deceiving due to their relatively harmless histopathological aspect. The usual morphological signs of tumor aggression, namely pleomorphism, nuclear atypia, hemorrhage, high cellular and mitotic activity, poorly correlate with the invasive potential of pituitary tumors, with their proliferation capacity, their tendency of post-surgical recurrence or with their global biological behavior.

Bionics, biological systems and the principle of optimal design.

The living world is an exciting and inexhaustible source of high performance solutions to the multitude of biological problems, which were attained as a result of a natural selection, during the millions and millions years evolution of life on Earth. This work presents and comments some examples of high performances of living beings, in the light of the universal principle governing the realm of living matter: Optimal Design Principle. At the same time, the transfer of these optimal solutions, from living matter to the technologies, is also discussed. This transfer is offering new and fertile perspectives to future technologies, which must be more efficient, cheaper and in perfect harmony with the biosphere.

Investigations on the influence of the experimental infection with the herpes simplex virus type 1 on the electrophoretic mobility of some cultured cells.

Two types of cell cultures, BSC and HE-p2, have been studied from the microelectrophoretic point of view. Determinations have been made for infected cells (collected at 48 or 72 hours after infection) and for control cells, immediately after their separation from the culture, or after preserving them for 24 hours or more in migration buffer. The electrophoretical mobility increases with an average of 10% in the case of infected cells, as compared to the controls. This parameter offers a distribution of values varying from the gaussian curve to the bimodal one. From the microelectrophoretic point of view, the HEp-2 cells are more stable and respond more uniformly than BSC cells.

Hydration forces involved in cellular interactions.

Cellular physical interactions are determinant in many and various biological processes: aggregation, adhesion, segregation, contact inhibition, fusion, etc. A real advance concerning the understanding of cellular interactions from a physical point of view has been performed of late, but a great many problems still remain to be clarified. Thus, DLVO theory extrapolated to cell-cell interactions, is unable to describe cellular interactions at very short distances of separation, where other forces play an important role. A sketch of the original form of DLVO theory, its criticism along with the nature and mechanism of the short range repulsive forces (hydration forces) are presented and discussed.