The regulatory function of α1B-adrenoceptors in mammalian heart homeostasis is controversial. The objective of the present study was to characterize the expression/activity of key proteins implicated in cardiac calcium handling (Na+/K+-ATPase and Ca2+-ATPases) and growth (ERK1/2, JNK1/2 and p38) in mice with cardiac-selective overexpression of constitutively active mutant α1B-adrenoceptor (CAMα1B-AR), which present a mild cardiac hypertrophy phenotype. Immunoblot assays showed that myocardial plasma membrane Ca2+-ATPase (PMCA) expression was increased by 30% in CAMα1B-AR mice (N = 6, P < 0.05), although there was no change in sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) expression. Moreover, total Ca2+-ATPase activity was not modified, but a significant increase in the activity of the thapsigargin-resistant (PMCA) to thapsigargin-sensitive (SERCA) ratio was detected. Neither Na+/K+-ATPase activity nor the expression of α1 and α2 subunit isoforms was changed in CAMα1B-AR mouse hearts. Moreover, immunoblot assays did not provide evidence for an enhanced activation of the three mitogen-activated protein kinases studied in this stage of hypertrophy. Therefore, these findings indicate that chronic cardiac α1B-AR activation in vivo led to mild hypertrophy devoid of significant signs of adaptive modifications concerning primary intracellular calcium control and growth-related proteins, suggesting a minor pathophysiological role of this adrenergic receptor in mouse heart at this stage of development.

Toxoplasma gondii is an intracellular protozoan infecting birds and mammals. Acute infection is asymptomatic in immune competent people. For immune deficient patients (acquired immune deficiency syndrome, lymphoma patients or those under steroids to prevent organ transplantation rejection) infection may be lethal. We describe an uncommon case of testicular toxoplasmosis in patient under steroids after organ transplantation with no positive serum test for HIV and/or systemic toxoplasmosis.

El Toxoplasma gondii es un protozoario intracelular que infecta aves y mamíferos. La infección aguda es asintomática en pacientes inmunocompetentes. En pacientes con deficiencia inmunológica (síndrome de la inmunodeficiencia adquirida, linfomas o pacientes sometidos a terapia con corticoides para prevención de rechazo de transplante de órganos) la infección puede ser fatal. Nosotros describimos un caso poco común de toxoplasmosis testicular en paciente sometido a transplante renal hace 6 años con serología negativa para el virus VIH y sin toxoplasmosis sistémica.

The Ising model has been an important theoretical tool in the understanding of phase transitions in ferroelectric materials. We first review how it relates to the underlying physics of order-disorder phase transitions in these systems, as well as mean-field results for the spontaneous polarization and the dielectric constant near the critical temperature. For hydrogen-bonded ferroelectrics, a term of interaction with an external transverse field is necessary to account for proton tunneling between the two minima of a double-well potential. Finally, we discuss both experimental and theoretical results for the problems of proton-lattice interactions, central peak dynamics, dynamical behavior of pseudo-one-dimensional ferroelectrics and pressure effects on hydrogen bonded ferroelectrics.