Production of aborted pollen in marsh species of Chenopodiaceae: evidence of partial male sterility in Suadeaea and Salsoleae species

The main objective of this study is to establish the level of pollen abortion prior to its release from the anther in species of Chenopodiaceae in marsh habitats and to compare this level among the taxons, locations and positions of the flowers in the dichasium and the relative positions of the anthers. We established the level of nonfunctional pollen formation in 39 samples belonging to 10 species, using lactophenol cotton blue staining. Aborted pollen grains were found to be significantly smaller than normal ones. The results revealed differences in the percentage of normal grains among different species and tribes studied: Atripliceae (56.1 ± 27.1%), Salicornieae (80.36 ± 16.52%), Suaedeae (54.7 ± 31.2%) and Salsoleae (32.5 ± 25.7%). In some species there were significant differences among the populations studied, but in species of Saliconieae we found no differences either between different positions in the dicasia or in the anther. In the tribes Suaedeae and Salsoleae, we postulate the existence of a system that maintains different levels of partial male sterility among individuals in the populations, which would reduce the autogamous fruit set rate and favor the cross-pollination rates of sterile male individuals. We base this on high intrapopulation variability at those levels, on the constancy with which they are presented in the different populations studied, and on the lack of interannual differences.     

Why change habits? Early modern medical innovation between medicalisation and medical culture

Based on a discussion of the concept of medicalisation and medical culture in Anglo-American, French-, and German-speaking historiography the paper argues that medical innovation in Europe from the sixteenth to the mid-nineteenth century should be approached in a different way. Instead of asking from the perspective of a too narrow concept of medicalisation why medical innovations were rejected by the population, (medical) historians should analyse medical culture and ask why people should have changed their health and illness behaviour. This conceptual argument is deduced from four empirical examples: the introduction of smallpox vaccination, "medical police," the problem of medical professionalization, and the questions arising around the relations between the healthy/sick and their practitioners.     

Nitric Oxide Production in Striatum and Pallidum of Cirrhotic Rats

Ammonium and manganese are neurotoxic agents related to brain metabolic disturbances observed after prolonged liver damage. The aim of this study was to assess the production of nitric oxide (NO) in the brain of cirrhotic rats exposed to manganese. We induced cirrhosis by bile duct ligation for 4 weeks in rats. From brain, striatum and globus pallidus were dissected out, and NO synthase activity and the content of nitrites plus nitrates (NOx) were determined. In pallidum we found a diminished constitutive NO synthase activity from cirrhotic rats, independently of manganese exposure. This result was confirmed by low levels of NOx in the same brain area (P<0.05, two-way ANOVA). This finding was not related to protein expression of NO synthase since no differences were observed in immunoblot signals between cirrhotic and sham-operated animals. Results from present study suggest that the production of NO is reduced in basal ganglia during cirrhosis.     

Decreased Nitric Oxide Production in the Rat Brain after Chronic Arsenic Exposure

Chronic arsenic exposure is associated with nervous system damage, vascular disease, hepatic and renal damage as well as different types of cancer. Alterations of nitric oxide (NO) in the periphery have been detected after arsenic exposure, and we explored here NO production in the brain. Female Wistar rats were exposed to arsenite in drinking water (4–5 mg/kg/day) from gestation, lactation and until 4 months of age. NOS activity, NO metabolites content, reactive oxygen species production (ROS) and lipid peroxidation (LPx) were determined in vitro in the striatum, and NO production was estimated in vivo measuring citrulline by microdialysis. Exposed animals showed a significantly lower response to NMDA receptor stimulation, reduction of NOS activity and decreased levels of nitrites and nitrates in striatum. These markers of NO function were accompanied by significantly higher levels of LPx and ROS production. These results provide evidence of NO dysfunction in the rat brain associated with arsenic exposure.     

Expression and characterization of the assimilatory NADH-nitrite reductase from the phototrophic bacterium Rhodobacter capsulatus E1F1

A nas gene region from Rhodobacter capsulatus E1F1 containing the putative nasB gene for nitrite reductase was previously cloned. The recombinant His₆-NasB protein overproduced in E. coli showed nitrite reductase activity in vitro with both reduced methyl viologen and NADH as electron donors. The apparent K _m values for nitrite and NADH were 0.5 mM and 20 μM, respectively, at the pH and temperature optima (pH 9 and 30°C). The optical spectrum showed features that indicate the presence of FAD, iron-sulfur cluster and siroheme as prosthetic groups, and nitrite reductase activity was inhibited by sulfide and iron reagents. These results indicate that the phototrophic bacterium R. capsulatus E1F1 possesses an assimilatory NADH-nitrite reductase similar to that described in non-phototrophic organisms.     

Influence of heart failure on nucleolar organization and protein expression in human hearts

We investigate for the first time the influence of heart failure (HF) on nucleolar organization and proteins in patients with ischemic (ICM) or dilated cardiomyopathy (DCM). A total of 71 human hearts from ICM (n=38) and DCM (n=27) patients, undergoing heart transplantation and control donors (n=6), were analysed by western-blotting, RT-PCR and cell biology methods. When we compared protein levels according to HF etiology, nucleolin was increased in both ICM (117%, p<0.05) and DCM (141%, p<0.01). Moreover, mRNA expression were also upregulated in ICM (1.46-fold, p<0.05) and DCM (1.70-fold, p<0.05. Immunofluorescence studies showed that the highest intensity of nucleolin was into nucleolus (p<0.0001), and it was increased in pathological hearts (p<0.0001). Ultrastructure analysis by electron microscopy showed an increase in the nucleus and nucleolus size in ICM (17%, p<0.05 and 131%, p<0.001) and DCM (56%, p<0.01 and 69%, p<0.01). Nucleolar organization was influenced by HF irrespective of etiology, increasing fibrillar centers (p<0.001), perinucleolar chromatin (p<0.01) and dense fibrillar components (p<0.01). Finally, left ventricular function parameters were related with nucleolin levels in ischemic hearts (p<0.0001). The present study demonstrates that HF influences on morphology and organization of nucleolar components, revealing changes in the expression and in the levels of nucleolin protein.     

Influence of ovariectomy on cardiac oxidative stress in a renovascular hypertension model

The aim of this study was to evaluate the potential influence of endogenous ovarian hormones on cardiac oxidative stress in renovascular hypertension. Female Wistar rats (N = 10 per group) were divided among 4 groups: (i) normotensive control; (ii) hypertensive control; (iii) normotensive ovariectomized; and (iv) hypertensive ovariectomized rats. To induce hypertension, 2-kidney 1-clip (2K1C) Goldblatt's method was followed. Blood pressure (BP) was enhanced (25%) in 2K1C and it was not further altered in hypertensive ovariectomized animals. Lipid peroxidation (measured by thiobarbituric acid reactive substances; TBARS) increased in heart homogenates after ovariectomy (253%) and was additionally augmented when associated with hypertension (by 28%). Superoxide dismutase and catalase activities were similar in both hypertensive groups. Hypertension enhanced glutathione peroxidase activity (75%), but the association with ovariectomy prevented this change. Total radical trapping antioxidant potential (TRAP) decreased in hypertensive rats (34%) and was recovered when associated with ovariectomy. However, this adaptation seems not to be sufficient to avoid the increased oxidative damage in ovariectomized hypertensive animals. These results suggest a protective role for physiological ovarian hormones in the cardiac oxidative stress induced by 2K1C hypertension.