Treatment with Standard and Low Dose of Conjugated Equine Estrogen Differentially Modulates Estrogen Receptor Expression and Response to Angiotensin II in Mesenteric Venular Bed of Surgically Postmenopausal Hypertensive Rats.

Standard hormone therapy for menopausal women [conjugated equine estrogen (CEE) 0.625 mg] has been associated with increased risk of venous thrombosis. Regimens containing a lower CEE dose (0.30 mg) have been used clinically to decrease side effects of supraphysiologic doses of estrogen. In this study, we determined the effects of standard (SD) and low dose (LD) of CEE on venular function in ovariectomized (OVX) spontaneously hypertensive rats (SHR). Contractions by angiotensin-II (Ang-II 10 µM) in perfused mesenteric venular bed were markedly increased in OVX (21.5 ± 1.3 mmHg) compared with Sham (14.7 ± 1.1 mm Hg, P < 0.05). CEE-SD did not modify Ang-II responses in OVX, whereas CEE-LD restored Ang-II contraction to Sham levels. Endothelial nitric oxide synthase (eNOS) inhibition by L-NAME increased Ang-II contractions in Sham and CEE-LD and was without effect in venules of OVX SHR and CEE-SD. In OVX there was decreased NO generation in association with diminished eNOS phosphorylation and increased O2- generation in the venular wall. CEE-LD reverted the deleterious effects of ovariectomy. Although CEE-SD augmented eNOS phosphorylation in OVX, it was unable to increase NO levels, probably owing to its inability to reduce O2- Distinct effects by CEE-SD and CEE-LD parallel the differential modulation of Ang-II and estrogen receptors. Compared with Sham, CEE-LD increases Ang II receptor type 2, whereas CEE-SD modified ERß expression in the venous bed. Interestingly, both CEE doses increased G protein-coupled estrogen receptor in OVX. Our data suggest that estrogen dose is an important factor for venous function. Although CEE-LD reversed deleterious effects of OVX, CEE-SD showed null effects despite its ability to increase eNOS activity.

Quantification of Listeria monocytogenes in minimally processed leafy vegetables using a combined method based on enrichment and 16S rRNA real-time PCR.

Modern lifestyle markedly changed eating habits worldwide, with an increasing demand for ready-to-eat foods, such as minimally processed fruits and leafy greens. Packaging and storage conditions of those products may favor the growth of psychrotrophic bacteria, including the pathogen Listeria monocytogenes. In this work, minimally processed leafy vegetables samples (n = 162) from retail market from Ribeirão Preto, São Paulo, Brazil, were tested for the presence or absence of Listeria spp. by the immunoassay Listeria Rapid Test, Oxoid. Two L. monocytogenes positive and six artificially contaminated samples of minimally processed leafy vegetables were evaluated by the Most Probable Number (MPN) with detection by classical culture method and also culture method combined with real-time PCR (RTi-PCR) for 16S rRNA genes of L. monocytogenes. Positive MPN enrichment tubes were analyzed by RTi-PCR with primers specific for L. monocytogenes using the commercial preparation ABSOLUTE QPCR SYBR Green Mix (ABgene, UK). Real-time PCR assay presented good exclusivity and inclusivity results and no statistical significant difference was found in comparison with the conventional culture method (p < 0.05). Moreover, RTi-PCR was fast and easy to perform, with MPN results obtained in ca. 48 h for RTi-PCR in comparison to 7 days for conventional method.

Vitamins C and E improve endothelial dysfunction in intrauterine-undernourished rats by decreasing vascular superoxide anion concentration.

Epidemiological studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension in adulthood. Ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) have antioxidant properties that could improve redox-sensitive vascular changes associated with hypertension. The authors determined whether vitamins C and E treatments ameliorate the hypertension and vascular function in male rats submitted to intrauterine undernutrition. Pregnant Wistar rats were fed either normal or 50% of the normal intake diets during the whole gestational period. At 14 weeks of age, male offspring of nutritionally restricted dams were divided into 3 subgroups: vehicle-treated (vehicle for 15 days, by gastric gavage, n = 9), vitamin C-treated (ascorbic acid, 150 mg/Kg/d for 15 days, by gastric gavage, n = 15) and vitamin E-treated (alpha-tocopherol, 350 mg/kg per day for 15 days, by gastric gavage, n = 15). Systolic blood pressure was determined before and after antioxidant treatments by the tail-cuff method. At 16 weeks of age, the rats were used for the study of microvascular reactivity and intravital fluorescence microscopy. Intrauterine undernutrition induced hypertension, and vitamins C or E treatments reduced the blood pressure levels. The decreased acetylcholine and bradykinin-induced vasodilation was restored in the vitamin-treated rats. These effects were associated with decreased vascular superoxide anion concentration. The results show that vitamins C and E reduce oxidative stress and high blood pressure levels, and improve vascular function in intrauterine-undernourished rats.