Morphological characteristics of the interpubic joint (Symphysis pubica) of rats, guinea pigs and mice in different physiological situations. A comparative study

The pubic joint of male and female rats, guinea pigs and mice was studied using the Picrosirius polarization method which selectively discloses the fibers of the collagenous system. Besides that, considerations were made regarding joint classification. In adult rats (both males and females, including intrapartum specimens), our results confirm those of earlier studies showing that the interpubic joint contains a central core of hyaline cartilage surrounded by fibrocartilaginous areas. Thus, in rats, the pubic joint should more properly be classified as a true synchondrosis. In virgin female guinea pigs and mice, the interpubic joint is formed of fibrocartilage (a true symphysis); whereas at term the bones are joined by a connective ligament, constituting a syndesmosis. Male mice have a similar (fibrocartilaginous) joint structure to virgin female mice, whereas male guinea pigs (like rats) have a hyaline cartilage joint. The foregoing observations indicate that the classification of the pubic joint depends upon the species, age, sex, and physiological reproductive stage studied. Species that are very similar in most other aspects (such as rats and mice) displayed different morphological features of the pubic joint to support the same reproductive processes. Together, the data reported here suggest that interspecies differences are likely to be found in other parameters and should be considered when choosing an appropriate animal model for research or teaching purposes.

[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.

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.

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.

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.

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.

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.

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).