Evaluation of the smooth muscle cell component and apoptosis in the varicose vein wall

This study was designed to evaluate the role of the smooth muscle cell and the apoptosis in the pathogenesis of the varicose vein. Segments of saphenous vein were obtained from healthy subjects and from those with varicose veins. The vein specimens were subdivided according to subject age (younger or older than 50 years) and according to the varicose vein source (distal or proximal). Morphological, ultrastructural, cell proliferation (anti-PCNA method) and cell death (TUNEL method) analysis were performed. The walls of healthy, control vein specimens acquired a more collagenous and papillomatous appearance with age. A slight increase in the number of TUNEL-positive cells was also observed in specimens from older subjects. The proportion of apoptotic cells was much greater in the varicose veins than in control specimens. Most cellular alterations were seen in proximal varicose segments obtained from young subjects. These specimens showed hypertrophic areas with a high degree of cellularity (both in the media and in the thickened intima). The highest proportion of apoptotic cells and collagenisation were also observed in these areas. The enhanced number of apoptotic cells in varicose veins observed mainly in proximal/young vein specimens could be responsible, at least in part, for the acceleration of the final fibrosclerotic process characteristic of the varicose vein wall.     

Investigating plant lipid biopolymers

This paper presents a review of the biological importance and occurrence of plant cutin, the main lipid biopolymer in higher plants. Its chemical composition and structure are reviewed and a short laboratory practical exercise on the extraction, purification and qualitative analysis of fruit cutin is presented.     

Tropane alkaloids from the leaves and stem bark of Erythroxylon alaternifolium and Erythroxylon rotundifolium

A novel 3alpha,6beta,7beta-triol tropane alkaloid esterified by two benzoyl residues was isolated from the leaves of the endemic cuban species, Erythroxylon alaternifolium. Another novel 3alpha,6alpha,7beta-triol tropane alkaloid esterified by trimethoxycinnamoyl and trimethoxybenzoyl residues was isolated from the leaves and stem bark of a second endemic cuban species, Erythroxylon rotundifolium. Their structures were elucidated as 3alpha,7beta-dibenzoyloxy-6beta-hydroxy-tropane and 3alpha-(3,4,5-trimethoxycinnamoyloxy)-7beta-(3,4,5- trimethoxybenzoyloxy)-6alpha-hydroxy-tropane by spectroscopic methods including 2D-NMR techniques.     

Growth-altering effects of sodium hypochlorite in cultured human dermal fibroblasts

Sodium hypochlorite, the most widely used antimicrobial active chlorine compound in chemical disinfection, is little used as an antiseptic in clinical practice. This study aimed to assess the capacity of hypochlorite to alter human dermal fibroblast growth in vitro in relation to the concentration and exposure time. Effects of decreasing concentrations of hypochlorite (0.5%-0.00025%) on fibroblast adherence capacity and proliferation, according to varying exposure times and fetal calf serum (FCS) concentrations were investigated combining XTT assay, which provides cytochemical quantification of metabolically-active cell number, and total cell protein content, an indirect method for assessing substrate-adhered cell number. Initial cytotoxicity was produced at 0.0075% hypochlorite within contact time of two hours, provoking concentration-dependent cell detachment. From 0.1% upwards, NaOCl exerted a profound cytotoxic effect on fibroblasts. At later stages (4 h) and concentrations > or = 0.01% hypochlorite produced dose-dependent mitochondrial dysfunction: cell survival progressively diminished from 71% to 10%. Cytotoxic effects were not significantly affected by exposure-time periods, probably because maximum chlorine is released within the first four hours. Hypochlorite concentrations from 0.005% to 0.00025% were found to have no inhibitory effects on cell growth; in fact, they appear to exhibit the opposite effect. Increments in protein content found after 24 h exposure ranged from 30% to 120% above control values. Hypochlorite is highly cytotoxic for fibroblasts at concentrations > or = 0.01% provoking concentration-dependent loss of cell adherence capacity and mitochondrial dysfunction. In contrast, a mitogenic effect was observed with concentrations < or = 0.005% which supports NaOCl as a source growth-promoting activity in cultured human fibroblasts. Hypochlorite proved to be a highly reactive molecule which inhibits or stimulates cell division according to the concentration.     

The expression and activity of monoamine oxidase A, but not of the serotonin transporter, is decreased in human placenta from pre-eclamptic pregnancies

Serotonin (5-HT) plays a pivotal role in pregnancy and a hyperserotonomic condition has been documented in pre-eclampsia. We have attempted to elucidate the possible participation of 5-HT as an aetiological factor in pre-eclampsia, by estimating the activity and expression of the 5-HT transporter (SERT) and monoamine oxidase A (MAO-A) in human placenta from full term normal (NG) and severe pre-eclamptic (PES) pregnancies. Uptake of 5-[1,2-3H] hydroxytryptamine binoxalate (specific radioactivity, 30.4 Ci/mmol) was determined in placental brush border vesicles by a rapid filtration technique. 5-HT metabolism in placental homogenate was measured using a HPLC-ECD system. Expression of SERT and MAO-A was determined by Western blot, using specific antibodies against the human SERT and MAO-A in placental tissues obtained from NG and PES. Our results, showed no significant difference in 5-HT uptake between both groups. However, 5-HT metabolism was significantly lower in placental homogenates from PES than in NG placentas, with the pathological preparations showing no MAO-A activity against 5-HT during the first 60 min of incubation (87% and 5% of metabolism of 5-HT initially added, NG and PES respectively). Western blot analysis showed a similar expression of SERT in BBMV from NG and PES. However, unlike for normal pregnancies, the expression of MAO-A in placental homogenates from PES was found to be very low, or almost negligible. These findings confirm our previous results and suggest that the higher plasma free 5-HT levels observed in severe pre-eclampsia could be mainly due to a reduction in placental MAO-A expression and activity and are not limited by the expression and uptake of 5-HT into the placental tissue.     

Direct intracardiac injection of umbilical cord-derived stromal cells and umbilical cord blood-derived endothelial cells for the treatment of ischemic cardiomyopathy

The development of new therapeutic strategies is necessary to reduce the worldwide social and economic impact of cardiovascular disease, which produces high rates of morbidity and mortality. A therapeutic option that has emerged in the last decade is cell therapy. The aim of this study was to compare the effect of transplanting human umbilical cord-derived stromal cells (UCSCs), human umbilical cord blood-derived endothelial cells (UCBECs) or a combination of these two cell types for the treatment of ischemic cardiomyopathy (IC) in a Wistar rat model. IC was induced by left coronary artery ligation, and baseline echocardiography was performed seven days later. Animals with a left ventricular ejection fraction (LVEF) of ≤40% were selected for the study. On the ninth day after IC was induced, the animals were randomized into the following experimental groups: UCSCs, UCBECs, UCSCs plus UCBECs, or vehicle (control). Thirty days after treatment, an echocardiographic analysis was performed, followed by euthanasia. The animals in all of the cell therapy groups, regardless of the cell type transplanted, had less collagen deposition in their heart tissue and demonstrated a significant improvement in myocardial function after IC. Furthermore, there was a trend of increasing numbers of blood vessels in the infarcted area. The median value of LVEF increased by 7.19% to 11.77%, whereas the control group decreased by 0.24%. These results suggest that UCSCs and UCBECs are promising cells for cellular cardiomyoplasty and can be an effective therapy for improving cardiac function following IC.     

WHAMM links actin assembly via the Arp2/3 complex to autophagy

Macroautophagy (hereafter autophagy) is the process by which cytosolic material destined for degradation is enclosed inside a double-membrane cisterna known as the autophagosome and processed for secretion and/or recycling. This process requires a large collection of proteins that converge on certain sites of the ER membrane to generate the autophagosome membrane. Recently, it was shown that actin accumulates around autophagosome precursors and could play a role in this process, but the mechanism and role of actin polymerization in autophagy were unknown. Here, we discuss our recent finding that the nucleation-promoting factor (NPF) WHAMM recruits and activates the Arp2/3 complex for actin assembly at sites of autophagosome formation on the ER. Using high-resolution, live-cell imaging, we showed that WHAMM forms dynamic puncta on the ER that comigrate with several autophagy markers, and propels the spiral movement of these puncta by an Arp2/3 complex-dependent actin comet tail mechanism. In starved cells, WHAMM accumulates at the interface between neighboring autophagosomes, whose number and size increases with WHAMM expression. Conversely, knocking down WHAMM, inhibiting the Arp2/3 complex or interfering with actin polymerization reduces the size and number of autophagosomes. These findings establish a link between Arp2/3 complex-mediated actin assembly and autophagy.     

Removal of the carboxy terminus of beta-tubulin subunit produces lateral annealing of microtubules with different orientations

1. Tubulin, lacking the carboxy terminus region of its beta subunit assembles into composite microtubule structures showing opposite polarity. 2. Since in these polymers, microtubules are laterally bound, this type of interaction could lead to the generation of microtubules with different polarities, as those found in some cellular types.