El cultivo celular en la investigación básica del cáncer de mama

Resumen La técnica del cultivo celular es la que ha permitido conocer el comportamientoin vitro de las células cancerosas. En esta revisión pretendemos introducir las peculiaridades básicas del cultivo celular, referido especialmente a líneas cancerosas mamarias, relacionar el origen de las líneas celulares más utilizadas en la investigación de este cáncer, mencionar las técnicas de laboratorio que pueden aplicarse sobre estos cultivos y ejemplificar la utilidad de las mismas, tomando como modelo diversos trabajos que estudian los efectos del factor de crecimiento epidérmico sobre líneas celulares hormonoindependientes de cáncer de mama.      

Sequential Role of Hippocampus and Amygdala, Entorhinal Cortex and Parietal Cortex in Formation and Retrieval of Memory for Inhibitory Avoidance in Rats

The hippocampus and amygdala, the entorhinal cortex and the parietal cortex participate, in that sequence, both in the formation and in the expression of memory for a step-down inhibitory avoidance task in rats. Bilateral infusion of AP5 or muscimol caused retrograde amnesia when given O min after training into both hippocampus and amygdala, when given or 180 min after training into the entorhinal cortex, or when given 180 min after training into the parietal cortex. Therefore, memory formation requires the sequential and integrated activity of all these areas mediated by glutamate NMDA receptors in each case. Pre-test administration of CNQX 1 day after training into hippocampus and amygdala, 1 or 31 days after training in entorhinal cortex, or 1, 31 or 60 days after training in the parietal cortex temporarily blocked retention test performance. Therefore, 1 day after training, all these brain structures are necessary for retrieval; 1 month later, the hippocampus and amygdala are no longer necessary for retrieval but the entorhinal and parietal cortex still are; and 60 days after training only the parietal cortex is needed. In all cases the mechanisms of retrieval require intact glutamate AMPA receptors.     

Noradrenergic and opioidergic influences on the antinociceptive effect of clomipramine in the formalin test in rats

Although tricyclic antidepressant are especially useful in the treatment of chronic pain conditions, most of the work about its mechanism of action has been made on acute pain tests. The present study was aimed at studying the role played by noradrenergic and opioidergic influences on the antinociceptive activity of subchronically administered clomipramine in the formalin test (a tonic pain model) in rats. Clomipramine produced antinociception after 7 days, administration (2.5 mg/kg/day), an effect equivalent to that obtained by acute morphine (5 mg/kg). The antinociceptive effect of clomipramine was inhibited by the following: nonspecific blocking of alpha₁-and alpha₂-adrenoceptors by phentolamine, specific blocking of alpha₁-adrenoceptors by prazosin; stimulation of alpha₂ receptors by clonidine; and blocking of the opioid receptors by naloxone. Blocking the alpha₂-receptors with yohimbine did not antagonize the effect of clomipramine. These results suggest that clomipramine produces antinociception in this test, partly via the participation of the endogenous opioid system and partly by further activating or potentiating previously activated noradrenergic pathways which are involved in the control of pain information.     

Tyrosine phosphorylation in mouse mammary hyperplasias

Tyrosine phosphorylation status was investigated during mousemammary tumor development using non-tumorigenic and tumorigenichyperplastic outgrowth lines. These outgrowth lines were comparedwith normal mammary glands from pregnant mice and with theircorresponding tumors. The levels of total tyrosine phosphorylationin proteins of hyperplastic and neoplastic tissues were 4.7-and3.4-fold higher than in the normal gland respectively. Theseresults indicate that increases in tyrosine phosphorylationoccur in the earliest stages of neoplastic development and arenot restricted to neoplastic cells per se. These results ledto the identification of the specific proteins showing highlevels of tyrosine phosphorylation. Of the eight molecular weightbands of proteins exhibiting detectable levels of tyrosine phosphorylation,the only proteins exhibiting consistently different degreesof phosphorylation between hyperplasias and tumors were of     

Unusual case of Haemophilus influenzae type b: Haemophilus influenzae type b meningitis cellulitis and subcutaneous abscess

An unusual case of beta-lactamase positive Haemophilus influenzae type b infection is reported. Clinical manifestations included meningitis, a left ankle subcutaneous abscess, and bilateral hand cellulitis. Discussion and review of literature are presented for the previously unreported association of this common childhood pathogen.     

Integration of bilateral whisker stimuli in rats: role of the whisker barrel cortices.

Recently, we demonstrated that neural responses within the whisker region of the primary somatosensory cortex (SIw) of rats are profoundly influenced by the spatiotemporal attributes of ipsilateral, as well as contralateral, whisker stimuli. As inactivation of one SIw eliminates in the intact SIw both ipsilaterally evoked responses and the influence of ipsilateral stimulation on contralaterally evoked activity, we proposed that interhemispheric interactions between the SIws may be important for integrating bilateral whisker information. To test whether rats can recognize the bilateral nature of a whisker stimulus, we developed a tactile discrimination task that required rats to conjointly determine distances to a left and a right discriminandum as equidistant or non-equidistant using only their facial whiskers. All rats trained in this task achieved performance levels indicative of an ability to integrate bilateral whisker information. Testing during unilateral, as well as bilateral, inactivation of the SIws indicated that rats rely on both SIws for detecting the bilateral nature of a whisker stimulus. Rats were unable to perform the task without both sets of whiskers, a fact that indicates that the whiskers (and not other modalities) were used to perform this task. The findings presented here indicate that rats can solve a task that requires the conjoint detection of left and right whisker-mediated distance information and implicate the SIws as central to this ability.