Relationship between late-life hypertension, blood pressure, and Alzheimer's disease

Relationship between late-life hypertension and Alzheimer's disease (AD) remains less clear. Both cross-sectional and longitudinal methods were used to examine whether systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), and self-reported hypertension (S-HTN) in late life were associated with having and developing AD. The cross-sectional examination included 1768 individuals with AD and 818 nondemented individuals, and AD was not significantly associated with S-HTN or any of blood pressure measures (S-HTN: P = .236; SBP: P = .095; DBP: P = .429; PP: P = .145; MAP: P = .162). In the longitudinal examination, 594 nondemented individuals, 171 with and 423 without S-HTN at entry, were included. Diastolic blood pressure was significantly related to the development of AD (P = .030) but not S-HTN (P = .251), SBP (P = .294) PP (P = .919), and MAP (P = .060). The association underscores the necessity of further investigation to outline the detailed mechanisms and biological relevance, if any, of late-life DBP to later AD.

Initial orthostatic hypotension in the young is attenuated by static handgrip

Initial orthostatic hypotension is common in children. Isometric handgrip increases arterial pressure, central blood volume, cardiac output, and total peripheral resistance. We show that in 14 subjects with initial orthostatic hypotension, isometric handgrip coupled with standing abolished symptoms of initial orthostatic hypotension and minimized decreases in blood pressure and cardiac output with standing.

Evaluation of hemodynamic and regional tissue perfusion effects of minimized extracorporeal circulation (MECC)

Minimized extracorporeal circulation (MECC, Maquet, Cardiopulmonary AG, Hirrlingen, Germany) is an established procedure to perform coronary revascularization. Studies showed positive effects of MECC compared to conventional cardiopulmonary bypass (CCPB) procedures in terms of transfusion requirements, less inflammation reactions, and neurological impairments. Recent retrospective studies showed higher mean arterial pressure (MAP) and a lower frequency of vasoactive drug use. We addressed this issue in this study. The hypothesis was to find a higher MAP during coronary bypass grafting surgery in patients treated with MECC systems. We performed a prospective, controlled, randomized trial with 40 patients either assigned to MECC (n = 18) or CCPB (n = 22) undergoing coronary bypass grafting. Primary endpoints were the perioperative course of mean arterial pressure, and the consumption of norepinephrine. Secondary endpoints were the regional cerebral and renal oxygen saturation (rSO2) as an indicator of area perfusion and the course of hematocrit. Clinical and demographic characteristics did not significantly differ between both groups. Thirty-day mortality was 0%. At four of five time points during extracorporeal circulation (ECC) MAP values were significantly higher in the MECC group compared to CCPB patients (after starting the ECC 60 +/- 11 mmHg vs. 49 +/- 10 mmHg, p = .002). MECC patients received significantly less norepinephrine (MECC 22.5 +/- 35 microg vs. CCPB 60.5 +/- 75 microg, p = .045). The rSO2 measured at right and left forehead and the renal area was similar for both groups during ECC and significantly higher at CCPB group 1 and 4 hours after termination of CPB. Minimized extracorporeal circulation provides a higher mean arterial pressure during ECC and we found a lower consumption of vasoactive drugs in the MECC group. There was a decrease in regional tissue saturation at 1 and 4 hours post bypass in the MECC group possibly due to increased systemic inflammation and extravascular fluid shift in the CCPB group.

Hypertension in pregnancy among HIV-infected women in sub-Saharan Africa: prevalence and infant outcomes

This analysis was performed to determine the prevalence of hypertension and association of MAP (mean arterial pressure) with birth outcomes among HIV-infected pregnant women not taking antiretrovirals. HIV-infected pregnant women, enrolled into the HPTN024 trial in Tanzania, Malawi and Zambia were followed up at 26-30, 36 weeks, and delivery. The prevalence of hypertension was <1% at both 20-24 weeks and 26-30 weeks and 1.7% by 36 weeks. A 5 mm Hg elevation in MAP increased the risk of stillbirth at 20-24 weeks by 29% (p = 0.001), 32% (p = 0.001) at 26-30 weeks and of low birth weight (LBW) at 36 weeks by 26% (p = 0.001). MAP was not associated with stillbirth at 36 weeks, LBW prior to 36 weeks, preterm birth, neonatal mortality or the risk of maternal to child transmission (MTCT) of HIV.

Stimulation of the ventral tegmental area enhances the effect of vasopressin on blood pressure in conscious rats

The mesolimbic dopamine system projects to a large number of forebrain areas and plays an important role in the regulation of locomotor activity, cognition and reward. We previously found evidence for a functional interaction between the mesolimbic dopamine system and circulating vasopressin and the present study was performed to test the hypothesis that mesolimbic dopamine stimulation modulates the cardiovascular effects of vasopressin. Sprague-Dawley rats were stereotaxically implanted with a guide cannula into the region of origin of the mesolimbic system, the ventral tegmental area, and instrumented with catheters into the abdominal aorta and jugular vein. One week later, separate groups of conscious rats were injected intravenously with 1, 3 or 10 ng kg(-1) of arginine-vasopressin or other vasopressor drugs before and after intra-ventral tegmental area injection of 10 nmol of neurotensin. Intra-ventral tegmental area injections of neurotensin had no significant effect on mean arterial pressure and heart rate but significantly potentiated the pressor response to intravenous administration of vasopressin when compared to saline-injections. However, the vasopressin-induced bradycardia was unaffected. Intravenous pretreatment with raclopride blocked the ability of neurotensin, injected into the ventral tegmental area, to potentiate the vasopressin-induced pressor response. Intra ventral tegmental area injections of neurotensin had no effect on the pressor response and bradycardia induced by intravenous angiotensin II or methoxamine. In conclusion, these results suggest that the mesolimbic dopamine system, in addition to its well-known role in the regulation of behaviour, modulates cardiovascular control by potentiating the effects of vasopressin on mean arterial pressure. British Journal of Pharmacology (2000) 129, 29 - 36