Piperine, active substance of black pepper, alleviates hypertension induced by NO synthase inhibition.

OBJECTIVES: The presented study is aimed on exploring the effects of black pepper on blood pressure in the rat model of experimental hypertension induced by chronic NO synthesis inhibition. BACKGROUND: Piperine, the compound of black pepper, can cause a significant decrease of blood pressure in normotensive rats possibly via calcium channel blockade, a pathway that is known to be effective in prevention of L-NAME (N(G)-nitro-L-arginine methyl ester) induced hypertension. METHODS: Wistar rats were administered clear water (C), L-NAME (40 mg/kg/day, L), piperine (20 mg/kg/day) in corn oil by oral gavage with L-NAME (LP) or without it (P) for 6 weeks. The systolic blood pressure was measured weekly. Specimens of thoracic aorta were processed in paraffin and histological slices were stained with hematoxylin and eosin, Mallory's phosphotungstic acid hematoxylin (PTAH), orcein, antibodies against inducible NO synthase (iNOS) and smooth muscle cells actin (SMCA). Microscopic pictures were digitally processed and morphometrically evaluated. RESULTS: L-NAME increased the blood pressure, cross-sectional area of aorta, media thickness, elastin and SMCA synthesis and PTAH positive myofibrils relative and absolute content in the aortic media, wheras it decreased percentual content of iNOS, elastin and SMCA. Piperine decreased the blood pressure rise from the third week of treatment, synthesis of elastin and the percentual and absolute content of PTAH positive myofibrils, however, it did not affect other parameters. CONCLUSION: Oral administration of piperine is able to partially prevent the increase of blood pressure caused by chronic L-NAME administration. This effect is probably caused by the blockage of voltage-dependent calcium channels and supported by filamentous actin disassembly (Tab. 1, Fig. 2, Ref. 35).

Red wine polyphenols affect the collagen composition in the aorta after oxidative damage induced by chronic administration of CCl(4).

Increased amount of collagen type I and decreased amount of type III is described in various pathological processes in the vascular wall. Polyphenols were shown to have protective effect on endothelium, decrease blood pressure and prevent oxidative damage induced by various stimuli. Tetrachlormethane (CCl(4)) is a toxic substance with known negative systemic effects induced by free radicals. Chronic administration of CCl(4) for 12 weeks led to an increase of collagen type I and a decrease of type III in the wall of aorta. Parallel administration of red wine polyphenols significantly reduced the increase of collagen type I, at the same time the content of type III rose to the level above controls. After 4 weeks of spontaneous recovery no changes were observed. If polyphenols were administered during the recovery period, there was a decrease of type I and an increase of type III collagen content in the aorta. It can be concluded that polyphenols have a tendency to lower the amount of type I and to increase the proportion of type III collagen in the wall of the aorta. These changes are significant in prevention or in regression of changes induced by chronic oxidative stress. This effect of polyphenols is most likely the result of their influence on MMP-1 and TIMP activities through which they positively influence the collagen types I and III content ratio in the vascular wall in favor of the type III collagen.

[The prevalence of cerebrovascular disease in the rural community of Salamá, Honduras, using the capture-recapture epidemiological method]. / Prevalencia de la enfermedad cerebrovascular en la comunidad rural de Salamá, Honduras, utilizando el método epidemiológico de captura-recaptura.

INTRODUCTION: Cerebrovascular disease (CVD) is one of the leading causes of mortality and disability in Honduras. In 2001 the first epidemiological study conducted into stroke or CVD in the urban district of Colonia Kennedy in Tegucigalpa, Honduras, was published; the prevalence rate was found to be 5.7 x 1000 inhabitants. To date few epidemiological studies have been carried out on CVD in rural areas of Central America. AIM: To determine the prevalence of CVD in the rural community of Salama, Olancho, Honduras, using the epidemiological method known as capture-recapture. SUBJECTS AND METHODS: The capture-recapture technique includes three sources of data: door-to-door interviews, research of medical records and interviews held with community leaders. All the residents in the rural community of Salama, Olancho, in north-western Honduras, were evaluated and the prevalence day was 5th May, 2005. The World Health Organisation's definition of CVD and the recommendations of the 'Global stroke initiative' were used. RESULTS: A total of 1121 households were visited, which involved a total population of 5608 inhabitants. The prevalence for CVD was found to be 3.6 x 1000 inhabitants. CONCLUSIONS: The prevalence rate for CVD in the rural community of Salama, Honduras, is similar to that reported for other rural regions of Latin America. The capture-recapture technique is recommended for conducting studies into the prevalence of stroke in rural areas.

Red wine polyphenols prevent endothelial damage induced by CCl4 administration.

It became evident in the present study that carbon tetrachloride (CCl(4)), in addition to its known liver and renal toxicity, causes serious damage to endothelial cells. The preventive effect of red wine on cardiovascular diseases has been documented in a number of human population studies as well as in animal experimental models. In this study, the endothelium protective effect of polyphenolic compounds isolated from red wine was studied in rats administered 0.5 ml of CC(4)/kg body weight intraperitoneally twice a week for 8 weeks. Endothelemia (endothelial cells/10 microl of plasma) was used as the marker of endothelial cell injury in vivo. Chronic CCl(4) treatment for 8 weeks lead to a 3-fold increase of free endothelial cells circulating in the blood when compared to the baseline values (2.5+/-0.3). Parallel oral administration of polyphenols 40 mg/kg/day significantly decreased the endothelemia. Polyphenolic compounds alone did not produce significant changes. Three weeks of spontaneous recovery after the 8-week treatment with CCl(4) did not lead to a marked decrease of endothelemia, but the administration of red wine polyphenols during the 3-week period significantly decreased free endothelial cells in the blood. It can be concluded that long-term administration of CCl(4) may serve as a useful experimental model of endothelial damage. The red wine polyphenolic compounds exert a powerful protective effect on endothelial cells from the injury caused by CCl(4). This effect was documented by decreased endothelemia that corresponded to diminished endothelial cell swelling and detachment evaluated by histology of the vascular intima. The endothelium protective effect may be one of the key factors that contribute to the preventive action of red wine on cardiovascular diseases.

Z-DNA, a new in situ marker for transcription.

Z-DNA forms transiently behind the active RNA polymerases, because of the mechanical torsional stress produced during transcription. In this paper, we explore the possibility that the distribution of Z-DNA stretches signals the sites related to nuclear transcription. To localize transcription, the in situ assay for active RNA polymerases, that allows the elongation of the already initiated transcripts but no initiation of new ones (run-on experiments), was carried out in isolated nuclei of Allium cepa L. root meristems. Both nucleolar and non-nucleolar sites appeared labelled. Nucleoli were most active in transcription than the multiple non-nucleolar foci altogether. In situ immunodetection of Z-DNA provided images that were comparable to those obtained after the run-on assay, with one exception: while Z-DNA and transcription sites were scattered throughout the whole nucleus, Z-DNA also accumulated in the nuclear periphery, where no transcription foci were detected in run-on assays. The peripheral Z-conformation signals might correspond to dsRNA segments present in the pre-mRNA in the process of their export to cytoplasm. The Z-containing structures nearly disappeared when non-nucleolar RNA polymerase II-dependent transcription had been previously abolished by the adenosine analogue DRB (5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole). This inhibition selectively decreased the amount of all nucleoplasmic Z structures. On the other hand, the inhibition of the nucleolar RNA polymerase I by cordycepin (3'-deoxyadenosine) prevented the presence of Z-DNA in nucleoli. We propose to use the in situ immunodetection of Z-DNA as a marker of the transcription level in both nucleolus and non-peripheral nucleoplasmic regions of nuclei. Co-detection of Z-DNA and of intermediate filament (IF) proteins, the major components of the nuclear matrix, was also carried out. The IFA antibody recognizes a conserved epitope essential for dimerization of the multiple IF proteins. They co-localized with most nucleolar Z-DNA, but not with the nucleoplasmic ones. In the nuclear periphery, the Z-positive signals were adjacent to the IF proteins constituting the lamina, though both signals did not often co-localize.