Prognostic value of 24-hour blood pressure variability.

OBJECTIVES: Evaluation of the prognostic value of 24-h blood pressure averages and 24-h blood pressure variability. DESIGN: After an initial thorough clinical and laboratory evaluation which included 24-h continuous ambulatory blood pressure monitoring, a group of hypertensive patients were re-examined after an average of 7.4 years. End-organ damage at the follow-up visit was related to different measures of blood pressure levels and variability obtained at the initial or the follow-up visit or both. METHODS: Seventy-three patients with essential hypertension of variable severity, in whom ambulatory blood pressure was monitored intra-arterially for 24 h (Oxford technique) were re-examined at a follow-up visit (including echocardiographic assessment of left ventricular mass index) 1-13 years later (mean 7.4 years). The severity of end-organ damage was quantified by a score and related to clinic blood pressure at follow-up and to (1) clinic blood pressure, (2) 24-h blood pressure mean, (3) 24-h short-term and long-term blood pressure variability, and (4) end-organ damage, all assessed at the initial visit (multiple regression analysis). RESULTS: The set of independent variables considered was significantly related to end-organ damage at follow-up (R = 0.51). The individual variables most important in determining end-organ damage at follow-up were clinic blood pressure at the follow-up visit (P < 0.01), the initial level of end-organ damage (P < 0.05) and long-term blood pressure variability (among half-hour standard deviation of 24-h mean blood pressure) at the initial evaluation (P < 0.05). The prognostic individual weight of the other haemodynamic parameters considered was less and not statistically significant. CONCLUSIONS: The results confirm that the level of blood pressure achieved by treatment and the degree of end-organ damage at the time of initial evaluation are important determinants of future end-organ damage related to hypertension. They also constitute the first longitudinal evidence that the cardiovascular complications of hypertension may depend on the degree of 24-h blood pressure variability.

Twenty-four hour blood pressure variability: clinical implications.

Ambulatory blood pressure monitoring techniques have allowed quantification of blood pressure variations occurring over a 24 hour time. The evaluation of these phenomena has not only allowed us to investigate the mechanisms responsible for cardiovascular regulation, but it has also provided information of clinical value. In particular there is evidence that blood pressure variations are significantly related to cardiovascular complications of hypertension. Progress in technology may allow us to extend these observations by means of non-invasive continuous blood pressure recordings to all those conditions where intra-arterial methods are not allowed.

Unconjugated bilirubin and the bile from light exposed Gunn rats inhibit intestinal water and electrolyte absorption.

Jaundiced babies undergoing phototherapy often develop diarrhoea. The cause of it is still uncertain. Increasing evidence supports a role of a secretory mechanism for the diarrhoea. We therefore studied the effects of bile from congenitally jaundiced rats undergoing phototherapy and of unconjugated bilirubin on rat small intestine in vivo and in vitro. Results suggest that: (1) the bile from homozygous Gunn rats under phototherapy has an anti-absorptive effect when tested in the perfused jejunum of normal Wistar rats; (2) unconjugated bilirubin has a dose dependent secretory effect on the intestinal transport of water and electrolytes, when tested in the same system. Alteration of cyclic AMP or cyclic GMP, known intracellular mediators of secretion, was not observed. We conclude that free bilirubin is an intestinal secretagogue acting by an as yet unknown mechanism, that may mediate the secretory type of diarrhoea in jaundiced neonates undergoing phototherapy.

Circadian blood pressure variations and their impact on disease.

Errors can be made when blood pressure is measured only by a single clinic measurement. Such assessments bear only a limited relationship to mean 24-h blood pressure and do not provide complete information on potentially important features of the circadian pattern of blood pressure. Measurement of clinic or "casual" cuff blood pressure by the doctor can produce a large, variable, and unpredictable overestimation caused by the pressor response associated with anxiety in the patient. Single cuff measurements rarely reflect the 24-h mean and classifications of severity based on cuff measurements are therefore subject to a large degree of overlap. Estimation of the response to antihypertensive treatment by casual cuff measurements is therefore subject to the same criticisms. Although superiority of measurement of 24-h mean blood pressure has not been demonstrated in any prospective controlled study, several cross-sectional investigations have shown that complications of hypertension relate more closely to the 24-h mean than to casual measurements. The degree of variability of blood pressure during a 24-h period (which can only be measured by 24-h monitoring) bears a relation to target-organ damage that is independent of mean blood pressure value. Nighttime blood pressure mean has been shown to correlate with target organ damage approximately as closely as daytime blood pressure mean, implying that antihypertensive drugs must act during the night as well as the day if they are to influence the complications of hypertension.

Relationship of 24-hour blood pressure mean and variability to severity of target-organ damage in hypertension.

Casual blood pressure (BP) can predict the development of cardiovascular morbidity and mortality, but the correlations between its values and the subsequent occurrence of such complications are low. This may depend on different individual resistance to the damage produced by hypertension. However, it may also depend on the recognized inability of causal BP to reflect accurately the 24-h mean and profile BP. In order to test the latter hypothesis, 24-h BP was recorded intra-arterially (Oxford method) in 108 hospitalized subjects with essential hypertension ranging from mild to severe. The 24-h means and standard deviations (i.e. variabilities) for systolic, mean and diastolic BP obtained by computer analysis of the BP tracing were related to the rate and severity of target-organ damage (TOD) assessed by clinical examination and quantified according to a predetermined score. The results confirmed that 24-h BP may be variably different from cuff BP among subjects. For nearly any value of cuff BP, subjects in whom the 24-h mean BP was low had a lower prevalence and severity of TOD than those in whom the 24-h mean BP was high (P less than 0.01). Furthermore, for nearly any level of 24-h mean BP, subjects in whom the 24-h BP variability was low had a lower prevalence and severity of TOD than those in whom the 24-h BP variability was high (P less than 0.05). These findings demonstrate that the severity of hypertension is more closely related to 24-h mean BP than to cuff BP values.(ABSTRACT TRUNCATED AT 250 WORDS)

The Wiskott-Aldrich syndrome: studies of platelets, basophils and polymorphonuclear leucocytes.

Platelets, basophils and neutrophils from a patient with the Wiskott-Aldrich syndrome (WAS) were exposed to stimuli that activate specific membrane receptor or directly initiate biochemical events (e.g. the Ca2+ ionophore A23187 and ionomycin or arachidonic acid). Platelets from this patient did not aggregate in response to ADP, collagen, thrombin or adrenaline, which activate specific membrane receptors. Platelet aggregation, however, was normal in response to compound A23187, ionomycin or exogenous arachidonic acid. Histamine release from basophils of the WAS patient was normal in response to anti-IgE, a formylated peptide (f-met peptide), and to A23187. Similarly, the release of the lysosomal enzymes, beta-glucuronidase and lysozyme, from neutrophils of the WAS patient in response to serum treated zymosan (Zx), f-met peptide, and A23187 was not significantly different from that of his parents and 13 normal donors. These results suggest that the primary defect in WAS is selectively present in platelets and is located in a biochemical step between receptor activation and Ca2+ influx and/or initiation of arachidonate metabolism.

[Efficacy of dietetic treatment in a case of galactosemia diagnosed late]. / Efficacia del trattamento dietetico in un caso di galattosemia tardivamente diagnosticata.

The authors describe a six months old girl affected by galactosemia, due to Galacto-1-phosphate Uridyl Transferase deficiency. The patient presented with hepatosplenomegaly and failure to thrive, without neurological impairment or cataracts. In this case removal of galactose from diet, although lately performed, resulted in normal growth and development. The authors emphasize the importance of ruling out galactosemia, even if clinical picture is unusual.