Rosario Rodríguez

Immunohistochemical Study of Cell Proliferation, Bcl-2, p53, and Caspase-3 Expression on Preneoplastic Changes Induced by Cadmium and Zinc Chloride in the Ventral Rat Prostate

This work was directed to evaluate immunoexpression of markers for apoptosis, resistance to apoptosis, and cell proliferation, as well as estimates of nuclear size in ventral prostate of rats treated with cadmium chloride and cadmium + zinc chloride because a possible protective effect of zinc has been postulated. The following variables were studied: volume fraction (VF) of Bcl-2 immunostaining, percentage of cells immunoreactive to proliferating cell nuclear antigen (LIPCNA) and p53 (LIp53), numerical density of caspase-3 immunoreactive cells (NV caspase-3), and estimates of volume-weighted mean nuclear volume (υV). The LIPCNA and VF of Bcl-2 were significantly increased in the treated animals. The dysplasias (independent of their origin) showed a significant increase of the LIp53, NV caspase-3, and υV in comparison with normal acini from treated and control animals. It can be concluded that cell proliferation is enhanced in long-term cadmium-exposed rats, and exposure to zinc combined with cadmium had no effect on any of the variables studied when comparing with normal acini. The increase of nuclear υV could indicate a more aggressive behavior for pretumoral lesions.

On the Closure Assumption in Extended Irreversible Thermodynamics

A new macroscopic aspect of one of the postulates of Extended Irreversible Thermodynamics is discussed. The role of parameters in the construction of the generalized entropy production is illustrated for the uniform shear flow of a dilute gas. Comparison with earlier work is made and some implications of the new assumption are mentioned. Introduction Linear Irreversible Thermodynamics (LIT) has been undeniably succesful in describing many irreversible processes in a variety of physico-chemical systems [1], However, in spite of its achievements, there are many nonequilibrium phenomena that do not fit into the scheme of LIT. Amongst these are those involving non-instantaneous response and non-linear constitutive equations. These limitations simply point out the necessity of generalizing LIT to cope with these nonequilibrium phenomena. One of the theories aiming at this generalization is extended irreversible thermodynamics (EIT). The development of BIT has been discussed extensively in the literature [2,3,4] and will not be pursued here, we only stress that although the formalism has been succesfully applied to several physical systems [5,6,7], the full analysis of the theory is far from being concluded. Some progress has been made towards the comparison between the predictions of EIT and experiment [8,9], but the derivation of the postulates of EIT from a microscopic point of view is still an open problem and at present is only partially understood [10,11]. Moreover, even the macroscopic consequences of these postulates have not been fully exploited and the main objective of this paper is to discuss a new aspect of one such postulate. Specifically, we consider the role of parameters, not belonging to the space of state variables, in the construction of the generalized entropy J.Non-Equilib. Thermodyn., Vol. 14, 1989, No. 1 Copyright

Effect of prolactin and bromocriptine on the population of prostate neuroendocrine cells from intact and cyproterone acetate-treated rats: stereological and immunohistochemical study.

This work deals with the quantification of serotonin‐immunoreactive prostate neuroendocrine cells (NECs) in rats exposed to prolactin in normal, cyproterone acetate‐exposed, and bromocriptine‐exposed animals to establish the possible influence of prolactin with or without androgenic blockade on this cell population. Thirty male peripubertal Sprague‐Dawley rats were grouped as controls (CT) and those treated with cyproterone acetate (CA), cyproterone acetate plus prolactin, cyproterone acetate plus bromocriptine, prolactin (PL), and bromocriptine (BC). The volume of ductal epithelium (Vep) and total number (NSER) of the NECs serotonin‐immunoreactive were measured. NECs were detected in the periurethral ducts. Compared to CT, Vep was increased in PL and BC and NSER was decreased in CA and increased in the prolactin or bromocriptine groups. The androgenic blockade decreases NSER in rat prostate; PL induces in normal and cyproterone acetate‐treated rats the increase of NSER; and BC exerts a local effect over the prostate similar to that described for PL. Anat Rec, 2007.

The underlying thermodynamic aspects of generalized hydrodynamics

Abstract We discuss the relation between extended irreversible thermodynamics and hydrodynamics. In particular, we derive systematically the results of the so-called generalized hydrodynamics and we relate our results with those of Mori and Zwanzigs theory, obtaining, thus, memory kernels compatible with irreversible thermodynamics.

Effect of Prolactin on the Population of Epithelial Cells From Ventral Prostate of Intact and Cyproterone Acetate‐Treated Peripubertal Rats: Stereological and Immunohistochemical Study

The interactions between steroid and nonsteroid hormones in the prostate are of special interest during the growth phase of the gland. The purpose of this work is to study the influence of prolactin (PL), with or without androgenic blockade, on epithelial cells from peripubertal rat ventral prostate. Twenty male peripubertal Sprague‐Dawley rats were grouped as controls, or treated with cyproterone acetate (CA), CA plus PL (CA‐PL), or PL. The total number (N total) of epithelial cells, and their labeling indices to proliferative cell nuclear antigen (LI PCNA), apoptosis (LI apoptosis) and androgen receptors (LI AR) were measured. CA and PL treatment significantly decrease the N total, but the LI PCNA was unchanged. We have observed a greater LI apoptosis in pharmacologically castrated animals without PL than in the rats with androgenic blockade with PL. The LI AR does not change with CA treatment in the ventral region, but the PL significantly increases it. Androgenic blockade and PL decrease the number of epithelial cells from the ventral prostate. These changes are not attributable to the decrease of cell proliferation, rather to the increase of epithelial apoptosis. The increase of cells expressing AR after treatment with PL might be attributed to the decrease of testosterone secretion caused by the hyperprolactinemia. PL does not modulate the size of the ventral prostate in prepubertal rats. Anat Rec, 2009.

Changes in the number and volume of NPY and VIP neurons from periprostatic accessory vegetative ganglia in pre- and peripubertal rats. A stereological study

The amount of neurons of periprostatic accessory ganglia in pre- and peripubertal rats was studied to ascertain whether the development of these autonomic ganglia is androgen-dependent. Stereological estimates of the volumes and number of neurons immunoreactive to protein gene product 9.5 (PGP 9.5), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) were carried out. Immunostaining of androgen receptors (AR) in the ganglia was also performed. The ganglionic neurons from the two groups studied were immunoreactive to PGP 9.5, NPY, and VIP. Almost all the neurons were immunostained for AR. The ganglionic volume showed a significant increase in peripubertal prostate in comparison with the prepubertal gland. No significant changes were observed with respect to the absolute number of neurons immunoreactive to all the antigens. The neuronal volume was significantly increased in peripubertal rats in comparison with prepubertal animals. These findings led us to the following conclusions: There is no evidence of neurogenesis during pubertal development in the periprostatic accessory ganglia of the rat. The increase of ganglionic volume in puberty is due to the growth in neuronal volume. There were no differences between the sizes of NPY and VIP neurons in pubertal periprostatic accessory ganglia. The development of periprostatic vegetative neurons is androgen-dependent.

Stereological Estimate of the Length of Microvessels and the Number, Proliferation and Apoptosis of Endothelial Cells in Prostate Cancer

Abnormal angiogenesis is a critical feature of many diseases, including cancers and their precursors. Although the association between prostate carcinogenesis and changes in microvascular architecture is well known, these changes are not well-documented from a quantitative point of view. The present work deals with stereological estimates of the number of quiescent and proliferative endothelial cells, and microvessel length in normal and prostate cancer tissues. Un- biased stereological measurements of numerical densities of proliferating cell nuclear antigen immunostained cells, non- proliferating endothelial cells, caspase 3 immunoreactive endothelial cells, and relative length (length density) of mi- crovessels, were performed in control and cancer specimens. There were no changes in either proliferation or apoptosis in carcinoma endothelial cells. A decrease of endothelial cell density, together with an increase of microvessel length den- sity, were detected in prostate cancer specimens. Therefore, the following conclusions can be drawn: a) The increase of angiogenetic activity in prostate carcinogenesis leads to an increment of the microvascular length; b) The amount of endothelial cells per vascular length decreases in prostate cancer; c) There is no decrease of endothelial apoptosis in cancer microvessels. d) The increase of the length den- sity of microvessels in prostate cancer is not directly associated to an enhancement of the endothelial proliferation; and e) The blood supply of epithelium was similar in both cancerous and normal prostate.

Cadmium and Zinc Chloride-induced Preneoplastic Changes in the Rat Ventral Prostate: An Immunohistochemical and Molecular Study

Cadmium chloride (Cd) is a toxicant that has been implicated in human prostate cancer (PCA). The goal of the present study was to evaluate the immunoexpression of markers for cell proliferation, apoptosis, resistance to apoptosis, and to determine mutations on segments of the bcl-2 gene, in preneoplastic lesions induced in rat prostate after treatment with Cd alone or in combination with zinc chloride (Zn). We evaluated: 1) The % of cells positively immunostained for the proliferating cell nuclear antigen (PCNA), 2) The % of apoptotic cells (evaluated by TUNEL), 3) The volume fraction of Bcl-2 immunostaining. 4) The mutations on a segment of 253 pb of bcl-2, in the ventral prostate lobe of normal and treated rats with Cd alone or in the presence of Zn in the drinking water for 18 mo. Our results indicate that the % of PCNA positive nuclei was significantly increased in preneoplastic prostatic acini of Cd-treated rats alone and in combination with Zn, compared to the normal acini of untreated animals. No significant changes were detected on the apoptotic rate or the volume fraction of Bcl-2. Moreover, no significant changes in the band pattern of the amplified segment of bcl-2 gene were observed after Cd treatment. In summary, our data indicate that, prostate dysplasia induced in rats by Cd increases proliferative activity, without significant changes in either apoptosis or bcl-2 immunoreactivity.

Temperature effects in the Rayleigh problem for a convected Jeffreys fluid

We use a thermodynamic approach to non-linear viscoelasticity which predicts a coupling between the stress tensor and the heat flux, to generalize the Rayleigh problem for an Oldroyd B model of a fluid. For a special choice of the external temperature gradient, we show that thermal effects do alter the hydrodynamic velocity field as well as the first and second normal stress differences. These quantities depend on renormalized parameters wich explicitly depend on temperature and on the strength of the coupling. In particular we find that in contrast to the isothermal situation, the second normal stress difference does not vanish. The possibility of an experimental verification of our theoretical predictions is also mentioned.

HEAT RELAXATION AND ANISOTROPY IN POLYMERIC MATERIALS

By using a general irreversible thermodynamic formalism, in a previous paper [1] we have derived constitutive equations which govern the anisotropic heat conduction that results from the coupling between the heat flux and the kinematics for a viscoelastic liquid. This coupling has led to generalizations of various rheological equations of state and some of its consequences have been studied elsewhere [2,3]. The main idea behind this approach is that the time evolution of the nonlinear non-equilibrium state of a viscoelastic liquid is described in terms of the dynamics of two types of state variables: conserved (such as the mass density and internal energy density e) and non-conserved or fast variables (such as the heat flux q and the stress tensor ). The dynamics of the former variables is governed by the familiar conservation laws, whereas for the evolution of the latter ones, equations of the relaxation type should be derived self-consistently from the theory itself. Within the framework of the so-called Extended Irreversible Thermodynamics (EIT) [4-7], this is done by assuming the existence of a non-equilibrium potential depending on both sets of variables. As a matter of fact, in the case of a viscoelastic liquid obeying the eight constants Oldroyd model, we have derived such relaxation equations in reference 1. The point to stress, though, is that these equations describe how the dynamics of the non-conserved variables affects the behaviour of the conserved ones and play the role of generalized constitutive relations describing the mutual interrelations between thermal effects and rheological properties. This idea was first used by Maxwell [8] to introduce a relaxation time in the heat flux constitutive equation, and later it was taken up by Cattaneo [9]. Ever since, the mathematical aspects of this problem have been developed very widely and recent work on the subject includes that of Schowalter [10], Ocone and Astarita [11], Müller and Villaggio [12], Joseph and Preziosi [13] and others.