PubMed Health⌕ Search

Biomedical subjects

H H Ortega

Publications and source records attributed to H H Ortega.

14 recordsLinked to original sources
PubMed2006

The role of ACTH in the pathogenesis of polycystic ovarian syndrome in rats: hormonal profiles and ovarian morphology.

Numerous hypotheses have been proposed about the pathogenesis of the polycystic ovarian syndrome (PCOS). However, hormonal control of persistent follicles has not been established. The objective of the present study was to compare the follicular structure and hormonal profiles of rats treated with the adrenocorticotrophic hormone (ACTH) with two experimental models of PCOS. ACTH-treated animals were compared with those exposed to continuous light, those treated with estradiol valerate, and with control (in proestrous and diestrous). Serum hormone levels, histomorphometrical changes, and immunoexpression of vimentin, cytokeratins, cadherins, and proliferating cell nuclear antigen (PCNA) were examined. Treatment with ACTH resulted in an elevation of corticosterone secretion with LH reduction but without changes in ovarian morphology. Although stress (or ACTH) stimulation may be only one of pathophysiological mechanisms involved in follicular cyst pathogenesis in other species, we do not have important evidence to suppose that this would happen in rats.

Adrenocorticotropic Hormone↗
PubMed2006

Oestradiol induced inhibition of neuroendocrine marker expression in Leydig cells of adult rats.

The objectives of this work were to determine the changes in the expression of neuroendocrine markers in Leydig cell by oestradiol treatment, and to determine whether testosterone is able to recover partially the effects of hormonal suppression induced by oestradiol. Adult male rats were injected daily with either 50 microg of oestradiol or oestradiol plus testosterone propionate (25 mg every 3 days) for 15 days. The animals were sacrificed and testicles were dissected and processed by routine histological protocols. FSH and LH serum levels were determined by radioimmunoassay. The visualization of antigens was achieved by the streptavidin-peroxidase immunohistochemical method. Antibodies against chromogranin A (CrA), S-100 protein (S-100), P substance (PS), synaptofisin (SYN), neurofilament protein (NF), gliofibrillary acidic protein (GFAP) and neuron specific enolase (NSE) were used. The mean LH and FSH serum concentrations were consistently suppressed with hormonal treatments. Intermediate filaments (NF and GFAP) showed no difference in their expression. The expression of S-100, NSE and SYN was significantly lower in both hormone-treated groups. In oestradiol-treated rats, the immunoreactivity of CrA and SP decreased significantly but was restored after testosterone supplementation. Although the nature and functions of many of these substances in Leydig cells remain unknown, these results are consistent with the hypothesis that the expression of some neuroendocrine markers is hormonally controlled.

Animals↗
PubMed2004

Immunohistochemical study of intermediate filaments and neuroendocrine marker expression in leydig cells of laboratory rodents.

The aims of this study were to detect the expression of intermediate filaments and to verify the existence of marker substances for neuronal and neuroendocrine cells within the interstitial Leydig cells of laboratory rodent's testes, such as it has been described in other species. Adult male rats, mice, gerbils, Syrian hamsters and guinea-pigs were used and the localization of the different markers was achieved by the streptoavidin-peroxidase immunohistochemical method. The present study demonstrates in all rodents studied a similar pattern of localization in Leydig cells of intermediate filaments (vimentin, cytokeratin, neurofilament 200 kD and glial fibrillary acidic protein) and other marker substances (S-100, CgA, substance P and neurone-specific enolase), which are typical of neuroendocrine (APUD cells or paraneurones) and glial cells. The expression of these substances, related to neurotransmitters or neurohomones and other proteins characteristic of neuroendocrine cells, could suggest that it is a neural crest derived cell. Although this study provides more evidences about the immunoexpression of neuronal and glial markers in Leydig cells, this fact cannot be related directly to their embryological origin, because the current data support the hypothesis of a mesenchymal origin of the Leydig cells.

Animals↗
PubMed2004

Constant light exposure causes dissociation in gonadotrophin secretion and inhibits partially neuroendocrine differentiation of Leydig cells in adult rats.

The objective of this work was to study the changes that occur in the Leydig cells of rats exposed to continuous light. The laboratory rat is considered a non-photoperiodic species because exposure to short photoperiod has little or no effect on the reproductive status. However, exposure of adult female rats to constant light induces polycystic ovaries, indicating that extreme changes in the photoperiod affect the reproductive function seriously. Adult male rats were placed under continuous light conditions for a duration of 15 weeks. After this period, the animals were killed and testicles were dissected and processed by routine histologic protocols. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) serum levels were determined by radioimmunoassay (RIA). The visualization of antigens was achieved by the streptavidin-peroxidase immunohistochemical method. Antibodies against chromogranin A, S-100 protein, P substance, synaptofisin, neurofilament protein-200, gliofibrillary acidic protein and neurone-specific enolase were used. The mean LH serum concentration was significantly lower, while the mean FSH level was significantly higher in treated animals. The expression of S-100, NSE, CrA, SP and SYN was significantly lower in treated animals. In conclusion, the constant light exposure acting directly at the pituitary level decreases LH secretion. The increased FSH secretion may be due to a partial reduction of the negative androgen feedback in the pituitary gland. Moreover, the constant light exposure affects the expression of some immunomarkers in Leydig cells, possibly because of the changes found in the gonadotrophin level and feedback mechanism.

Animals↗
PubMed2003

Collagen remodelling in the guinea-pig uterine cervix at term is associated with a decrease in progesterone receptor expression.

In human and guinea-pig parturition, progesterone withdrawal and estrogen action are not mediated by changes in their circulating levels. Instead, these events might be promoted by changes in the responsiveness of the uterus and cervix to progesterone and estrogen via changes in their receptors. In this study, the guinea-pig model was used to investigate whether high levels of progesterone and estrogen at term are associated with regional changes in PR and ERalpha levels in uterus and cervix. PR and ERalpha profiles were established in both subepithelium and the muscular layer of the cervix and the lower uterine horns during pregnancy, parturition and postpartum; while collagen remodelling was measured in the subepithelium. Our data showed that collagen remodelling involved in cervical ripening is temporally and spatially associated with a decrease in PR, whereas high expression of ERalpha is observed. This association was found in the subepithelium of the cervical tissue but not in the same region of the uterus. The muscular region of the cervix and uterus also present a transiently decreased expression of PR while ERalpha levels remain high. Thus, the present results indicate that, before parturition, diminished responsiveness of the cervix to progesterone might be caused by a decrease in PR levels and that this may be the mechanism of functional progesterone withdrawal. The guinea-pig was further validated as an animal model for human parturition studies.

Animals↗
PubMed2001

Bcl-2 correlates with tumor ploidy and nuclear morphology in early stage prostate carcinoma. A fine needle aspiration biopsy study.

We evaluated the nuclear morphology, ploidy, bcl-2 expression and in situ apoptosis in sections of fine-needle aspiration (FNA) biopsy specimens of thirty-one randomly selected Stage B prostate carcinomas. Sections of paraffin-embedded pelleted cells obtained from FNA biopsy specimens were studied. Nuclear grade was determined according to the WHO system. Nuclear morphometry and DNA ploidy were carried out using an automated image analyzer. We used immunostaining and the TUNEL method to evaluate bcl-2 expression and in situ apoptosis. The median nuclear area increased with increasing nuclear grade. Ploidy analysis showed that 54.8% of tumors were diploid, 3.2% tetraploid and 41.9% aneuploid. Bcl-2 overexpression was found in 10 of 31 tumors. There was a significant positive correlation between bcl-2 expression and nuclear area (r(s): 0.45 p < 0.01). Nine of ten bcl-2-positive tumors had a nuclear area larger than the median of the series, and 70% of bcl-2-positive tumors were of the aneuploid type. The apoptotic index had a negative correlation with nuclear area, and the lowest indexes were found in aneuploid tumors. Bcl-2 expression showed a highly significant association with both parameters of high aggressiveness: nuclear size and aneuploidy. The combined evaluation of nuclear morphology, ploidy and cell survival parameters might better identify patients with poor prognosis among early stage prostate carcinomas diagnosed by FNA biopsies.

Apoptosis↗
PubMed2001

Relaxin has a minor role in rat mammary gland growth and differentiation during pregnancy.

Growth and differentiation of mammary gland is associated with numerous hormones and a variety of cell-cell, cell-matrix interactions. This study addressed the role of relaxin (Rlx) on these processes. Morphologic and biochemical changes that occur throughout the second half of pregnancy are reported. Temporal patterns and spatial distributions of markers useful to evaluate proliferation, secretion, and collagen remodeling were established. To evaluate the role of Rlx, an ablation/replacement animal model was used. Considering Rlx secretion pattern, two periods were selected: d 11 through d 13, and d 20 through d 23. In the stroma, the extracellular compartment showed changes associated with the lack of Rlx. Collagen remodeling within the lobuloalveolar structure, measured by a significant increase in collagen birefringence, decreased at d 12, d 21, and d 22. Parenchymal structures were less sensitive to the absence of Rlx than stroma. Epithelial cell proliferation was lower in Rlx-deficient rats only at d 12, and alpha-lactalbumin expression decreased at d 21 and d 22. Both lobuloalveolar diameter and percentage of area occupied by these structures showed no changes. In the absence of Rlx, some of the studied markers showed statistically significant differences in scattered days; these do not make clear trends. No differences were found on d 23 on any of the studied parameters suggesting that compensatory mechanisms might be activated to overcome the effects of the absence of Rlx. Unlike the critical role of Rlx either in uterine cervix dilation or in nipple development during rat pregnancy, Rlx had a minor role in growth and differentiation of rat mammary gland.

Animals↗
PubMed2001

Differential distribution of the fibres of the collagenous and elastic systems and of glycosaminoglycans in the rat pubic joint.

The pubic joint of male and female rats was studied at the light- and electron microscopical levels using methods that selectively disclose the extracellular matrix fibres and glycosaminoglycans. The interpubic tissue showed no difference between sexes (including pregnant and intrapartum females). The medial ends of the pubic bones were covered by articular caps of hyaline cartilage that blended in the midline. The whole articular cartilage was covered dorsally and ventrally (as well as craneally and caudally) by a typical perichondrium. The differential distribution of the fibres of the collagenous and elastic systems in the pubic joint agreed with the results reported in the literature for other rat cartilages. Collagen fibres, composed mainly of type-I collagen, were localised to the fibrous perichondrium and bone. Type-II collagen was localised to the central nucleus of hyaline cartilage, whereas reticulin fibres (rich in type-III collagen) were found in the adventitial loose connective tissue adherent to the most superficial layer of the perichondrium. The central nucleus of hyaline cartilage possessed the two types of elastic-related fibres: elaunin fibres were localised mainly to the chondrogenic layer of the perichondrium, whereas oxytalan fibres were found in the matrix that surrounded the chondrocytes. The bulk of the glycosaminoglycans present in the pubic joint cartilage corresponded to hyaluronic acid and chondroitin sulphate. The propriety of classification of the rat pubic joint as a true synchondrosis (instead of symphysis), and the fact that the unaltered pelvis of the rat seems to be adequate for normal parturition, are discussed.

Animals↗
PubMed2001

[Identification of fungi in tissues and cultures: the importance of argirophilic substances on its cellular walls].

An experimental development based on the combination of microwaves action with one of the methods of silver staining by Del Río Hortega is presented. Material from pathological tissues and culture of fungi were studied. Besides morphological studies, were considered the causes of reduction from ionic to metalic silver, some characteristics of the silver reagent and its relationship with histochemical constitution of cellular walls. It is pointed the rapidity in fungi demonstration, the satisfactory definition of affected tissues, the advantages of working with a stable reagent, the omission of carcinogenetic substances, the possibility of stain fungical structures in previously stained materials with anilinic techniques, and the extent of the method to cultured materials without necessity of previous formaldehidic fixation.

Adult↗
PubMed2000

Lectinhistochemical and cytometrical evaluation of the corpus luteum of the rat at the end of pregnancy.

Most studies on the biochemistry and structure of the corpus luteum have focused on elucidating the processes of progesterone synthesis and release. In the present work, the histochemical composition of the corpus luteum of the rat was evaluated using lectinhistochemistry on rats at the end of pregnancy (days 18-23). We also analysed the morphology of the luteal cells, to characterize the changes attributable to regression in this organ. Seven biotinylated lectins were used (CON-A, WGA, DBA, SBA, PNA, RCA and UEA-I) following pre-set protocols (ABC method). The average diameter and area of the cells and their nuclei were measured. High reactivity of the luteal cells was observed with CON-A and a lower reactivity with WGA. The capillary endothelium gave positive reactivity with WGA and to a certain extent with SBA, PNA and RCA. Vesicular structures were intensely stained with DBA, and were more abundant in sections from animals with more advanced pregnancy, which could be attributable to cellular debris, on the basis of their morphologic characteristics. There were no significant differences among the cytometric variables analysed in comparisons of the values corresponding to the different days of gestation. These observations, together with previous research, suggest that, on the day of delivery, the corpus luteum of the rat is in the very early stages of structural regression, with no changes at the morphological level, but with changes at the molecular level.

Animals↗
PubMed1999

Microwave-enhanced of a method of silver impregnation applied in dermatohistopathology.

An experimental development based on the combination of microwaves action with one of the methods of silver staining by Del Río Hortega is presented. Materials from normal and pathological tissues were studied. The stuff were fixed in 10% formalin and received a paraffined embedding. The impregnation was made with ammoniacal silver carbonate in a domestic microwave oven during twelve seconds at 375 w. As a result of this, a time shortage of the technique, the high degree of definition of the nuclear, cytoplasmatic and extracellular matrix (collagenus fibbers with an unsteady reticular representation) details and the easy visualization of mitosis was observed. Also, omitting the reduction, they were clearly evidenced the argirophilics granules (melanin pigment).

Basal Cell Carcinoma↗
PubMedDate not supplied

Transcoronary sinus administration of autologous bone marrow in patients with chronic refractory stable angina Phase 1.

PURPOSE: Based on our preclinic studies with autologous unfractionated bone marrow (AUBM) via coronary sinus with transitory occlusion, a clinic study in patients with chronic stable angina was designed. The objectives were to evaluate safety, tolerance and feasibility. METHODS AND MATERIALS: A multicenter prospective study with inclusion and exclusion criteria defined by an Independent Clinical Committee was carried out. Fourteen patients underwent transcoronary sinus administration of freshly aspirated and filtered AUBM (60-120 ml). Safety and tolerance were evaluated. Feasibility was evaluated with Seattle Angina Questionnaire (SAQ), Canadian Cardiovascular Society (CCS) angina classification (baseline-Day 180), myocardial perfusion (baseline-Day 90) with independent core laboratory and coronary angiography (baseline and Day 30). RESULTS: There were no changes in the safety and tolerance parameters. Preliminary clinical efficacy at Day 180 disclosed a significant improvement of 38%, evaluated by the SAQ. The CCS angina classification shows that the mean angina class was 3.0+/-0.55 at baseline and improved to 2.0+/-0.00 at Day 180 (P <.001). Semiquantitative radionuclide perfusion imaging (core lab) showed a significant improvement at Day 90 in 13/14 patients, with a mean improvement of 24% at rest (P <.01) and 33% at stress (P <.05). Coronary angiography showed more collateral vessels in 9/14 patients. CONCLUSIONS: We can conclude that AUBM via coronary sinus with transitory occlusion is tolerable and safe. Significant improvement in the myocardial perfusion at Day 90 and in the quality of life at Day 180 was observed.

Angina Pectoris↗
PubMedDate not supplied

Transcoronary sinus delivery of autologous bone marrow and angiogenesis in pig models with myocardial injury.

PURPOSE: The aim of the investigation is to study myocardial injury on pig model with two objectives: (1) feasibility of stimulating angiogenesis with fresh autologous bone marrow; (2) administration of the same fresh autologous bone marrow via coronary sinus with transitory occlusion. METHODS: A controlled study was done in animal model with three phases, in a study group of 12 pigs (bone marrow administration) as well as in control group of 4 pigs (saline administration). Phase 1-production of coronary stenosis and myocardial injury; Phase 2-two weeks later, administration of bone marrow through coronary sinus with 10 min occlusion in the study group and saline solution in the control group. Phase 3-two weeks later, histological staining with hematoxylin-eosin and inmunohistochemical staining with monoclonal antibody for smooth muscle alpha-actin were conducted on both study and control groups. RESULTS: The percentage of angionenesis observed in the study group was 91% and 0% in control group. Counting of positive actin in affected and control areas showed statistically significant differences in relation to both groups: study group (1.37 vs. 0.79) and control group (0.47 vs. 0.51). The percentage of mononuclear immature cells observed in the myocardium in the study group was 25% and in the control group was 0%. There was no increment in the coronary collateral circulation when comparing coronary angiography. CONCLUSIONS: Autologous bone marrow in animal model with experimental myocardial injury enhances angiogenesis, as well as vessels with smooth muscles. The transitory occlusion of the coronary sinus might be an effective way to administer cells as those from the bone marrow.

Animals↗