Invasive cells in the placentome of Andean populations of Mabuya: an endotheliochorial contribution to the placenta?

New world lizards of the genus Mabuya have the most specialized level of placentotrophy among reptiles known to date, and related to that, they have the most complex allantoplacenta characterized by a series of morphological specializations that converge with those known for eutherian mammals. One of these specializations is the placentome that is found in the embryonic pole of the incubation chamber. In the mature allantoplacenta, this structure is morphologically the most complex, which could support an important amount of nutrient exchange between mother and fetus. According to the relationship between the chorioallantois and the syncytial uterine epithelia, the placenta of Mabuya populations shows some interesting similarities to the synepitheliochorial type. Recently, cells of chorionic origin have been found invading the syncytial uterine epithelium, and in very close proximity with uterine blood vessels. In this study, we describe the relationship between these invasive chorionic cells, the uterine syncytium, and the subjacent blood vessels of several populations of this genus, by means of high resolution optical microscopy and transmission electron microscopy. Cell groups originating from the chorion, of variable size and shape, penetrate the uterine syncytial epithelium extending complex cytoplasmic projections that come in contact with uterine capillaries and form an extensive and complex double-membrane system that surrounds the capillary. The close relationship between the chorion and the maternal circulation suggests that the Mabuya placentome shows some characteristics of an endotheliochorial placenta. This finding constitutes so far the only documented example of an endotheliochorial placentation in Reptilia.

Cellular and extracellular behavior in the gerbil (Meriones unguiculatus) ventral prostate following different types of castration and the consequences of testosterone replacement.

Mongolian gerbils (Meriones unguiculatus) were grouped into two experimental groups: GEx.01 suffered orchiectomy and after 30 days received doses of testosterone cipionate (T), while GEx.02 received weekly and alternated doses of the anti-androgens cyproterone acetate and flutamide for 30 days, and the animals were then euthanized. Structural evaluation reveals a more intense reduction in epithelial height in GEx.02. Smooth muscle cells (SMC) presented a star-shaped aspect after 30 days of hormonal ablation and basal membrane was shown to be more intensely grooved in GEx.01. In both groups, after hormonal replacement, recovery in epithelial height could be noted and the SMC presented its phenotypes, but an increase in RER was seen, characterizing a modulation from its contractile to secreting phenotype. In conclusion, the prostate presented involution capacity after androgen ablation and the ability to reorganize after hormonal replacement, but events resulting from orchiectomy and subsequent T replacement were shown to be more aggressive to the prostate.

Bone marrow subendosteal microenvironment harbours functionally distinct haemosupportive stromal cell populations.

In adult animals, bone marrow is the major site of blood cell production, which is controlled by interactions between the local stroma and blood cell progenitors. The endosteal/subendosteal environment comprises bone-lining and adjacent reticular cells and sustains haemopoietic stem cell (HSC) self-renewal, proliferation and differentiation. We have questioned the specific role of each of these stroma cells in controlling HSC fate. We have isolated two distinct stroma-cell populations containing subendosteal reticulocytes (F-RET) and osteoblasts (F-OST) from periosteum-free fragments of murine femurs by a two-step collagenase-digestion procedure. Both populations produce similar extracellular matrix (collagen I, laminin, fibronectin, decorin), except for collagen IV, which is low in F-OST. They also express osteogenic markers: osteopontin, osteonectin, bone sialoprotein and alkaline phosphatase (ALP). The quantity and activity of ALP are however higher in F-OST. When co-cultured with bone marrow mononuclear cells or lineage-negative haemopoietic progenitors, F-OST stroma induces low proliferation and high maintenance of early haemopoietic progenitors, whereas F-RET stroma induces high short-term proliferation and differentiation. Analysis by reverse transcription/polymerase chain reaction has revealed higher levels of Jagged-1 expression by F-OST cells than by the F-RET population. Thus, two adjacent stroma cells (subendosteal and endosteal) play distinct roles in controlling the stem-cell capacity and fate of HSC and probably contribute distinctly to HSC niche formation.

Ultrastructural pathology of Golgi apparatus of nerve cells in human brain edema associated to brain congenital malformations, tumours and trauma.

The alterations induced by ischemia and anoxia upon smooth endoplasmic membranes are studied in 38 patients with congenital malformations, brain tumours and brain trauma. The effects of vasogenic and cytotoxic brain edema are examined in the Golgi apparatus of nerve and endothelial cells. Samples of cortical biopsies were conventionally processed for transmission electron microscopy. Cortical biopsies were performed according to the basic principles of Helsinki declaration. Slices of 2 to 5 mm were immediately fixed in the surgical room in 4% glutaraldehyde-0.1 M sodium phosphate buffer, pH 7.4 at 4 degrees C, and postfixed in 1% osmium tetroxide in similar buffer. The pathological alterations of the Golgi complex were studied in samples with moderate and severe brain edema. Moderate edema was mainly found in congenital malformations and severe edema in brain trauma and tumours. In some severely edematous neurons, observed in hydrocephalus associated to Arnold-Chiari malformation, small vesicular type Golgi complexes and atrophic ones were observed, characterized mainly by partial or total disappearance of stacked Golgi cisternae and presence of congregated vesicular profiles. In brain trauma and tumours the Golgi complex showed enlargement and fragmentation of the stacked cis- medial- and trans-Golgi cisternae and vacuolization of trans-Golgi network. In addition, an increased formation of Golgi and coated vesicles was observed in the cis- and trans-Golgi regions. Most Golgi and clathrin coated vesicles were observed throughout the cytoplasm suggesting an increased vesicular transport. In severe edema the nerve cell plasma membranes appeared fragmented, presumably due to an interference of the protein insertion process into the plasma membrane. In brain trauma, a hypertrophic Golgi complex was observed in some nerve cells and endothelial cells of cortical capillaries, with increased formation of Golgi and coated vesicles. The ischemia and anoxia associated to the vasogenic and cytotoxic brain edema induced enlargement, fragmentation and disappearance of stacked Golgi cisternae.

Ultrastructural characteristics of the testicular capillaries in the dog (Canis familiaris, L.).

The main ultrastructural and cytophysiological characteristics observed on the testicular capillaries in the dog concern exocytosis and endocytosis processes, probably related to fluid and solute transport through the cells.

Corroboración bioquímica del compromiso endotelial en la preeclampsia severa

En este estudio prospectivo de casos y controles se investigó si las concentraciones elevadas de fibronectina celular plasmática informadas previamente en mujeres preeclámpticas reflejan probablemente disfunción endotelial. Nosotros encontramos además mayores concentraciones plasmáticas materias de fibronectina celular, mayores niveles de factor de von Willerbrand, activador tisular del plasinógeno e inhibidor -1 del activador del plasinógeno en el plasma materno, ofreciendo una corrobación bioquímica de disfunción endotelial en la preeclampsia severa

Placenta humana chagásica: alteración estructural y citoquímica de vasos sanguíneos / Human chagasic placenta: structural and cytochemical changes of blood vessels

Diversos autores han demostrado que los vasos sanguíneos coronarios pueden tener alguna participación en la patogenia de las alteraciones cardíacas en la enfermedad de Chagas. El objetivo del presente trabajo fue detectar alteraciones estructurales y citoquímicas en vasos sanguíneos de placentas humanas a término mediante microscopía óptica y electrónica, considerando la posibilidad de su participación en la patogenia del pasaje transplacentario del agente causal del Chagas. En dos de seis placentas chagásicas provenientes de embarazadas a término con serologías positivas para enfermedad de Chagas, se halló estrechamiento u oclusión de vasos fetales de las vellosidades coriales con aspecto hialinizado de sus paredes mediante microscopía óptica y actividad de fosfatasa ácida aumentada en el endotelio vascular mediante ultracitoquímica. El estrechamiento de la luz vascular mediante ultracitoquímica. El estrechamiento de la luz vascular podría deberse a la participación del músculo liso y del endotelio.

Placenta humana chagásica: alteración estructural y citoquímica de vasos sanguíneos / Human chagasic placenta: structural and cytochemical changes of blood vessels

Diversos autores han demostrado que los vasos sanguíneos coronarios pueden tener alguna participación en la patogenia de las alteraciones cardíacas en la enfermedad de Chagas. El objetivo del presente trabajo fue detectar alteraciones estructurales y citoquímicas en vasos sanguíneos de placentas humanas a término mediante microscopía óptica y electrónica, considerando la posibilidad de su participación en la patogenia del pasaje transplacentario del agente causal del Chagas. En dos de seis placentas chagásicas provenientes de embarazadas a término con serologías positivas para enfermedad de Chagas, se halló estrechamiento u oclusión de vasos fetales de las vellosidades coriales con aspecto hialinizado de sus paredes mediante microscopía óptica y actividad de fosfatasa ácida aumentada en el endotelio vascular mediante ultracitoquímica. El estrechamiento de la luz vascular mediante ultracitoquímica. El estrechamiento de la luz vascular podría deberse a la participación del músculo liso y del endotelio. (AU)

Endotelio e plaquetas na doenca vaso-oclusiva pulmonar / Endothelium and platelets in pulmonary vascular obstructive disease

A doenca vaso-oclusiva pulmonar e a resultante final de uma serie de alteracoes estruturais que ocorrem na parede dos vasos, sobretudo arteriais, habitualmente designadas por remodelagem vascular. Todos os elementos celulares, incluindo componentes da matriz extra-celular, estao direta ou indiretamente envolvidas no processo. Tem sido enfatizada a importancia fisiopatologica de mecanismos interativos envolvendo a parede vascular e elementos do sangue circulante. Estudos recentes, incluindo dados do nosso laboratorio, indicam a ocorrencia de importante alteracoes estruturais e funcionais das celulas endoteliais nesta sindrome. Paralelamente, tem sido cada vez mais ressaltado o papel das plaquetas, cujo envolvimento direto no processo vaso-oclusivo ja se encontra plenamente estabelecido. A presente revisao tem por objetivo discutir alteracoes estruturais e funcionais envolvendo celulas endoteliais e plaquetas na doenca vaso-oclusiva pulmonar, com enfase para os mecanismos interativos

Regression of aneurysms in Kawasaki disease: a pathological study.

The pathology of five aneurysms resected from four patients with Kawasaki disease was examined to elucidate the mechanisms of regression. (1) Marked intimal thickening was present in all five aneurysms. (2) Two patients treated with aspirin early in their course showed well-regenerated endothelium and marked thickening of the intima without massive thrombus; the thickened intima was rich in smooth muscle cells. These aneurysms maintained an adequate lumen of similar diameter to normal arteries, and some regressed angiographically. (3) Two patients untreated with aspirin in the acute phase had intimal thickening associated with massive thrombus formation and calcification. The pathologic appearances were similar to those of early atherosclerosis. One patient died suddenly of myocardial infarction. We conclude that the angiographically demonstrated phenomenon of aneurysm regression may result from intimal thickening mainly caused by the proliferation of smooth muscle cells not associated with massive thrombus. The thickened intima associated with massive thrombus may cause ischemic heart disease and simulate atherosclerosis. It is possible that the administration of aspirin may prevent massive thrombus formation. We hypothesize that Kawasaki disease may be an etiologic factor in some cases of early atypical coronary atherosclerosis.

[Ultrastructural observations on experimental shock lung]. / Observaciones ultraestructurales en el "pulmón de choque" experimental.

Intercellular junctions in the alveolar epithelium and in the capillary endothelium in the dogs after hemorrhagic shock (mean BP 40 mm Hg for 3 hours) and from control dogs were observed in the electron microscope using the freeze-fracture and etch technique. Following shock, tight junctions (zonulae occludentes) in the alveolar epithelium which were well developed with may strands in control animals showed alterations in substructure. Some desintegration and disappearance of junctional strands in "focal" regions were occasionally observed in the endothelium as well. The increased pulmonary capillary permeability observed physiologically after hemorrhagic shock may be explained by such alterations of endothelial zonulae occludentes.