Sperm morphological abnormalities appearing in the male rabbit reproductive tract

The role of the excurrent duct system in producing and/or eliminating morphologically abnormal spermatozoa may modify the semen parameters and interfere with sperm fertilizing capacity. To study this process, changes in the morphology of spermatozoa during their transit through the reproductive tract in sexually mature rabbits were investigated. The incidence of head, midpiece and tail abnormalities as well as of multiple defects in a single spermatozoon, and the position of the cytoplasmic droplet along the sperm midpiece were evaluated in samples from the testis, 6 regions of the epididymis and the vas deferens. Spermatozoa were characterized by rapid migration of the cytoplasmic droplet when passing from the proximal to the distal caput of the epididymis, and spermatozoa with no droplet predominated in the distal epididymis and vas deferens. In passing from the testis to the proximal caput of the epididymis, the incidence of spermatozoa with an abnormal midpiece and those with multiple defects decreased significantly. The proportion of spermatozoa with abnormal heads was also lower in the testis, but no statistically significant differences were found, whereas there was no change in the proportion of those with abnormal tails. These results indicate that there must be a mechanism for the disposal of defective spermatozoa. No evidence of spermiophagy by luminal macrophages was observed in the extracts, although a few spermatozoa exhibited signs of degeneration, suggesting, that although intraepithelial phagocytosis has not been clearly demonstrated in the nonexperimental rabbit, sperm cells may undergo a form of autolysis within the lumen of the duct.     

Coevolutionary interactions in a host–parasite system

Interactions between parasitic cuckoos and their hosts represent a classic example of coevolution, where adaptations in the parasite to exploit the host select for defences, which in turn select for new parasite adaptations. Current interactions between the two parties may be at an evolutionary equilibrium or, alternatively, a coevolutionary arms race may be taking place. By taking into account the effect of gene flow in 15 European magpie ( Pica pica ) populations, we studied the coevolutionary interactions with its brood parasite, the great spotted cuckoo ( Clamator glandarius ). Our results suggest that, in Europe, magpies and cuckoos are engaged in an ongoing coevolutionary process because, despite controlling for the large amounts of gene flow among different magpie populations, we still found a positive relationship between host defence (i.e. foreign egg recognition and rejection) and parasite selection pressure.     

Detection of beta-1,6-glucanase isozymes from Trichoderma strains in sodium dodecyl sulphate-polyacrylamide gel electrophoresis and isoelectrofocusing gels.

The filamentous fungus Trichoderma produces, under specific growth conditions, several extracellular fungal cell wall degrading enzymes, amongst them beta-1,6-glucanases. These enzymes seem to play an important role in the antagonistic action of Trichoderma against a wide range of fungal plant pathogens. In this report we describe two different methods for the specific detection of the activity of beta-1,6-glucanase isozymes in gels. After sodium dodecyl sulphate-polyacrylamide gel electrophoresis, beta-1,6-glucanase activity can be assayed in the gel by renaturation of the enzyme, incubation with an overlay agarose gel containing solubilized pustulan (a commercially available beta-1,6-glucan), followed by the staining of the agarose gel with Congo Red. In native isoelectrofocusing gels, as little as 1 mU can be detected after incubation with solubilized pustulan followed by a detection reaction of the released reducing sugars with 2,3,5-triphenyltetrazolium chloride. The latter technique has been successfully applied to the screening of beta-1,6-glucanase isozymes from different Trichoderma strains under different growth conditions.     

Different mechanisms of protection against apoptosis by valproate and Li+.

Acute treatment with valproate and Li+ was found to protect cultured cerebellar granule cells against apoptosis induced by low K+ (5 mM). Because the protection was unaffected by MK801 (N-methyl-D-aspartate receptor inhibitor), an increase in glutamate release cannot be responsible for the observed neuroprotection. Insulin also protects against low-K+-induced apoptosis of cerebellar granule cells. This protection is totally dependent on LY294002 (a phosphatidylinositol 3-kinase inhibitor). These results suggest a role for phosphatidylinositol 3-kinase in the neuroprotection induced by insulin. Likewise, and in contrast with the results observed with Li+, the protection induced by valproate is also dependent on insulin and LY294002. Moreover, valproate (a branched-chain fatty acid) does not change the plasma membrane microviscosity under physiological conditions. These results suggest that valproate protects against low-K+-induced apoptosis by acting in the phosphatidylinositol 3-kinase/protein kinase B pathway. The protection by Li+ is independent of this transduction pathway.     

Activation of Phosphatidylinositol 3-Kinase, but Not Extracellular-Regulated Kinases, Is Necessary to Mediate Brain-Derived Neurotrophic Factor-Induced Motoneuron Survival

Chick embryo spinal cord motoneurons develop a trophic response to some neurotrophins when they are maintained in culture in the presence of muscle extract. Thus, after 2 days in culture, brain-derived neurotrophic factor (BDNF) promotes motoneuron survival. In the present study we have analyzed the intracellular pathways that may be involved in the BDNF-induced motoneuron survival. We have observed that BDNF activated the extracellular-regulated kinase (ERK) mitogen-activated protein (MAP) kinase and the phosphatidylinositol (PI) 3-kinase pathways. To examine the contribution of these pathways to the survival effect triggered by BDNF, we used PD 98059, a specific inhibitor of MAP kinase kinase, and LY 294002, a selective inhibitor of PI 3-kinase. PD 98059, at doses that significantly reduced the phosphorylation of ERKs, did not show any prominent effect on neuronal survival. However, LY 294002 at doses that inhibited the phosphorylation of Akt, a down-stream element of the PI 3-kinase, completely abolished the motoneuron survival effects of BDNF. Moreover, cell death triggered by LY 294002 treatment exhibited features similar to those observed after muscle extract deprivation. Our results suggest that the PI 3-kinase pathway plays an important role in the survival effect triggered by BDNF on motoneurons, whereas activation of the ERK MAP kinase pathway is not relevant.     

Extracellular vesicles do not contribute to higher circulating levels of soluble LRP1 in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDCM) is a frequent cause of heart transplantation. Potentially valuable blood markers are being sought, and low‐density lipoprotein receptor‐related protein 1 (LRP1) has been linked to the underlying molecular basis of the disease. This study compared circulating levels of soluble LRP1 (sLRP1) in IDCM patients and healthy controls and elucidated whether sLRP1 is exported out of the myocardium through extracellular vesicles (EVs) to gain a better understanding of the pathogenesis of the disease. LRP1 α chain expression was analysed in samples collected from the left ventricles of explanted hearts using immunohistochemistry. sLRP1 concentrations were determined in platelet‐free plasma by enzyme‐linked immunosorbent assay. Plasma‐derived EVs were extracted by size‐exclusion chromatography (SEC) and characterized by nanoparticle tracking analysis and cryo‐transmission electron microscopy. The distributions of vesicular (CD9, CD81) and myocardial (caveolin‐3) proteins and LRP1 α chain were assessed in SEC fractions by flow cytometry. LRP1 α chain was preferably localized to blood vessels in IDCM compared to control myocardium. Circulating sLRP1 was increased in IDCM patients. CD9‐ and CD81‐positive fractions enriched with membrane vesicles with the expected size and morphology were isolated from both groups. The LRP1 α chain was not present in these SEC fractions, which were also positive for caveolin‐3. The increase in circulating sLRP1 in IDCM patients may be clinically valuable. Although EVs do not contribute to higher sLRP1 levels in IDCM, a comprehensive analysis of EV content would provide further insights into the search for novel blood markers.     

Long-term platinum retention after treatment with cisplatin and oxaliplatin

Background  

The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin.     

El anciano en la unidad de geriatría de agudos

Although the implementation of acute geriatric units (AGUs) in general hospitals has a grade A of evidency, in Spain, only 12% of them have this resource. The estimation of geriatric especializad beds for the care of acute frail elderly people is of 2.6/1000 inhabitants older than 75 years. AGUs have demonstrated to reduce the functional loss associated with the hospitalization and to increase the percentage of older people that can return home, without increases in mortality nor costs. In this review we present the characteristics of patients who benefit from AGUs, the services offered, the structure and functioning of the unit, the role of the professionals that work in it and the quality indicators that must be acomplished.