Chronic hydroxytyrosol feeding modulates glutathione-mediated oxido-reduction pathways in adipose tissue: a nutrigenomic study.

BACKGROUND AND AIM: Hydroxytyrosol (HT) is the most prominent phenolic component of olives, olive oil, and their by-products, e.g. olive mill waste water. As the link between HT consumption (via extra virgin olive oil intake) and better cardiovascular prognosis is being scientifically validated, HT is entering the market as a potentially useful supplement for cardiovascular disease prevention. One of the target organs in cardiometabolic prevention is the adipose tissue, where inflammation, oxidative stress, and secretion of adipocytokines contribute to cardiovascular risk. METHODS AND RESULTS: We explored the nutrigenomic effects of long-term supplementation with nutritionally-relevant doses of HT, i.e. 0.03 gm% - with specific reference to the adipose tissue and glutathione metabolism - and we explored underlying mechanisms in vitro. We show that HT modulates the antioxidant network in the adipose tissue, as mediated by glutathione (GSH) and associated enzymes. We also confirmed the GSH-modulating activities of HT in cultured adipocytes, where low, physiological HT concentrations were able to blunt the H2O2-induced GSH/GSSG alteration indicative of oxidative stress. In terms of surrogate markers of cardiovascular disease, we recorded significantly decreased circulating leptin concentrations in mice fed with HT as compared with controls. CONCLUSIONS: HT - in nutritionally relevant amounts - is able to positively modulate the glutathione-driven antioxidant enzymatic machinery in the adipose tissue. Because HT is generally recognized as safe (GRAS) and exhibits an excellent safety profile in vitro and in vivo, its future employment as adjunct treatment of metabolic syndrome can be envisioned, pending specific trials.

Clinical management guidelines for subarachnoid haemorrhage. Diagnosis and treatment.

OBJECTIVE: To update the Spanish Society of Neurology's guidelines for subarachnoid haemorrhage diagnosis and treatment. MATERIAL AND METHODS: A review and analysis of the existing literature. Recommendations are given based on the level of evidence for each study reviewed. RESULTS: The most common cause of spontaneous subarachnoid haemorrhage (SAH) is cerebral aneurysm rupture. Its estimated incidence in Spain is 9/100 000 inhabitants/year with a relative frequency of approximately 5% of all strokes. Hypertension and smoking are the main risk factors. Stroke patients require treatment in a specialised centre. Admission to a stroke unit should be considered for SAH patients whose initial clinical condition is good (Grades I or II on the Hunt and Hess scale). We recommend early exclusion of aneurysms from the circulation. The diagnostic study of choice for SAH is brain CT (computed tomography) without contrast. If the test is negative and SAH is still suspected, a lumbar puncture should then be performed. The diagnostic tests recommended in order to determine the source of the haemorrhage are MRI (magnetic resonance imaging) and angiography. Doppler ultrasonography studies are very useful for diagnosing and monitoring vasospasm. Nimodipine is recommended for preventing delayed cerebral ischaemia. Blood pressure treatment and neurovascular intervention may be considered in treating refractory vasospasm. CONCLUSIONS: SAH is a severe and complex disease which must be managed in specialised centres by professionals with ample experience in relevant diagnostic and therapeutic processes.

Polyphenols and cardiovascular disease: a critical summary of the evidence.

Epidemiological studies are clear: diets in which plant foods provide the major portion of caloric intake, e.g. the Mediterranean and the Japanese diets, are associated with a reduced risk of certain degenerative diseases like cancer and atherosclerosis. Although fats and proteins in plants, as opposed to those of animal origin, are responsible to some extent for these protective effects, the contribution of other plant food components may also be relevant. In the past few years, research on polyphenols has remarkably expanded and is unveiling several biological activities of these compounds. Alas, the marketing departments of several industries are jumping ahead of solid scientific evidence; as a consequence, unsubstantiated claims are being made and whole foods or fortified, enriched, or enhanced foods are being created and sold. Science is beginning to corroborate some of these claims, but much more research is needed and several myths are to be disproven. In this mini-review we critically discuss the current limitations of polyphenol research and we contend that, in addition to their putative antioxidant action, several biochemical and physiological processes might be influenced by polyphenols.

[Neuropsychological and behavioural impairments resulting from bilateral thalamic infarct]. / Alteraciones neuropsicológicas e infarto talámico bilateral.

The neuropsychological characteristics of a patient with a bilateral thalamic infarct in the posterior communicating artery territory due to basilar artery thrombosis are described. MRI examination showed bilateral thalamic acute ischemic lesions in the zone anterior to the tuberothalamic branches. In the cognitive exploration, the patient showed verbal and visual memory disorders, impairment of the executive functions including inability to generate and make decisions and behavioural disorders including lack of inhibition, euphoria, and occasional aggressiveness. Two months later the patient had improved in the neuropsychological test scores but still suffered from severe recent memory loss, and certain behavioural disorders including lack of inhibition and euphoria. Other cases on thalamic infarcts with cognitive and behavioural impairments due to disconnection of the front subcortical pathways have been described in the literature.

A review of the state of research into the role of iron in stroke.

Iron is a double edged sword for living systems, as it is essential for a wide range of metabolic processes while it also has potential deletereous effects. Oxidative metabolism during ischaemic stroke together with high iron content in the brain synergise to increase the oxidative damage. High plasma ferritin, as a measurement of iron stores, and high cerebrospinal fluid ferritin have been related to poor outcome in stroke patients. Iron has been found in pooled gruels of atheromatous lesions and has been related to other diseases. Further epidemiological studies are required to determine the effect of iron on the development of cardiovascular diseases. Until the precise effect of iron overloading is established it is recommended that iron supplements should only be prescribed when there is a clear deficiency.

Pyruvate carboxylase from Rhizobium etli: mutant characterization, nucleotide sequence, and physiological role.

Pyruvate carboxylase (PYC), a biotin-dependent enzyme which catalyzes the conversion of pyruvate to oxaloacetate, was hypothesized to play an important anaplerotic role in the growth of Rhizobium etli during serial subcultivation in minimal media containing succinate (S. Encarnación, M. Dunn, K. Willms, and J. Mora, J. Bacteriol. 177:3058-3066, 1995). R. etli and R. tropici pyc::Tn5-mob mutants were selected for their inability to grow in minimal medium with pyruvate as a sole carbon source. During serial subcultivation in minimal medium containing 30 mM succinate, the R. etli parent and pyc mutant strains exhibited similar decreases in growth rate with each subculture. Supplementation of the medium with biotin prevented the growth decrease of the parent but not the mutant strain, indicating that PYC was necessary for the growth of R. etli under these conditions. The R. tropici pyc mutant grew normally in subcultures regardless of biotin supplementation. The symbiotic phenotypes of the pyc mutants from both species were similar to those of the parent strains. The R. etli pyc was cloned, sequenced, and found to encode a 126-kDa protein of 1,154 amino acids. The deduced amino acid sequence is highly homologous to other PYC sequences, and the catalytic domains involved in carboxylation, pyruvate binding, and biotinylation are conserved. The sequence and biochemical data show that the R. etli PYC is a member of the alpha4, homotetrameric, acetyl coenzyme A-activated class of PYCs.

Characterization of Rhizobium phaseoli Sym plasmid regions involved in nodule morphogenesis and host-range specificity.

Two nodulation regions from the symbiotic plasmid (pSym) of Rhizobium phaseoli CE-3 were identified. The two regions were contained in overlapping cosmids pSM927 and pSM991. These cosmids, in a R. phaseoli pSym-cured strain background, induced ineffective nodules on Phaseolus vulgaris roots. Transconjugants of Rhizobium meliloti harbouring pSM991 induced nodule-like structures on bean roots, suggesting that this cosmid contains host-range determinants. Analysis of deletions and insertional mutations in the sequences of pSM991 indicated that the genes responsible for the induction and development of nodules in P. vulgaris are organized in two regions 20 kb apart. One region, located in a 6.8 kb EcoRI fragment, includes the common nodABC genes. The other region, located in a 3.5 kb EcoRI fragment, contains information required for host-range determination.