The persistent sciatic artery.

BACKGROUND: A persistent sciatic artery (PSA) is a rare vascular anomaly with an estimated incidence of 0.03-0.06%. During early embryonic development, the sciatic artery usually disappears when the superficial femoral artery has developed properly. This study aimed to assess the clinical presentation and outcome of a PSA. METHOD: A systematic review of all cases of PSA published between 1964 and 2007 was performed. RESULTS: In this review, 159 PSAs were described in 122 patients. The mean age at which the PSA was discovered was 57 years, and the incidence was equally distributed with regards to gender. The majority of PSAs was unilateral (70%) and of the complete type (79%). Ninety-one patients (80%) presented with symptoms including intermittent claudication, ischaemia, a pulsating mass or neurological symptoms. An aneurysm was found in 48%, a stenosis in 7%, an occlusion of the PSA in 9% and an occlusion of an artery distal to the PSA in 6% of the subjects. The treatment depended on the symptoms and classification of the PSA. In nine cases (8%), an amputation was required eventually. CONCLUSION: The PSA is a rare anomaly with a high incidence of complications including aneurysm formation and ischaemia that may lead to amputation. Strategies for follow-up could not be deduced from the available literature.

Cardiovascular response to physical stress in offspring of hypertensive parents: Dutch Hypertension and Offspring Study.

Blood pressure (BP) regulatory mechanisms were studied in youngsters with contrasting risks for hypertension, based on parental history, during physical stress. As a static exercise, an isometric handgrip task (22% of maximal force during 5 min) was used and a dynamic exercise task was performed on a bicycle ergometer. At rest and during stress, BP and heart rate were recorded. In order to study the adaptation of the cardiovascular system to physical stress, cardiac output and total peripheral resistance were measured in addition to indices of vagal and sympathetic influences on the heart. Heart rate and cardiac output declined significantly more in offspring of hypertensive parents during static exercise (difference in heart rate: -2.5 +/- 1.2 bpm, P = 0.04; difference in cardiac output: -9.0 +/- 4.6%, P = 0.05). This is most likely the result of a larger increase in the total peripheral resistance in youngsters at risk (difference: 13.2 +/- 6.8%, P = 0.06). No differences between the two groups were found in reactivity of BP or in the indices of sympathetic activation or vagal inhibition of the heart. The offspring of hypertensive parents showed an attenuated increase in stroke volume during the dynamic exercise task (difference at the first cycling level: -11.5 +/- 5.4%, P = 0.04), while no difference in neural activity or heart rate was found. Youngsters with a parental history of hypertension show an enhanced reactivity of total peripheral resistance during static exercise. This does not lead to a higher BP response in this group, most probably because of a larger decrease of the cardiac output. During dynamic exercise the physiological increase in stroke volume is blunted in offspring of hypertensive parents.

Calcium metabolism and familial risk of hypertension.

There is circumstantial evidence that disturbances of calcium metabolism are implicated in primary hypertension. From a large number of observational epidemiological studies, data have shown that a low dietary calcium intake increases the risk for high blood pressure. There is no general sensitivity for the effects of inadequate calcium intake, but subgroups of hypertensive patients have been described characterized by reduced serum ionized calcium levels, increased urinary excretion of calcium, raised intracellular calcium levels, reduced cellular membrane calcium binding, and other indicators of a relative calcium need. Some of these changes, however, may be secondary to blood pressure elevation. The family history approach enables to study the pathophysiology of early primary hypertension, at a stage at which blood pressure differences between future hypertensive subjects and normotensive subjects are still limited. In the Dutch Hypertension and Offspring Study, young normotensive subjects were studied selected on the basis of presence or absence of familial predisposition for hypertension. The findings show that disturbances in calcium metabolism are present in the early phase of primary hypertension and may precede the development of high blood pressure. Moreover, they suggest that changes in calcium metabolism may be a characteristic of familial hypertension and could reflect a genetic basis for calcium sensitive hypertension. The presence of a relatively reduced serum calcium and increased plasma PTH [1-84] level in the offspring of hypertensive parents indicates that calcium balance in prehypertensive subjects is maintained at a higher level of circulating PTH. The implications of these findings in relation to other available data are discussed.

Cardiovascular response to mental stress in offspring of hypertensive parents: the Dutch Hypertension and Offspring Study.

OBJECTIVE: To compare blood pressure-regulating mechanisms during mental stress in two groups of offspring with contrasting risk for hypertension. DESIGN: Cardiovascular reactivity to two different types of mental stressors was studied in adolescents and young adults with two hypertensive or two normotensive parents. The two tasks used were intended to evoke either a predominantly adrenergic cardiac response (a memory search task) or a predominantly vascular response (a reaction-time task with visual search and tone avoidance). METHODS: Blood pressure and heart rate were recorded at rest and during stress. To study adaptations of the cardiovascular system to mental stress, cardiac output, total peripheral resistance and indices of vagal and sympathetic influences on the heart were measured. RESULTS: The reactivity of systolic blood pressure (SBP) to the memory search task was significantly higher in offspring of hypertensive parents, which resulted in a longer recovery after the task. In contrast, during the reaction-time task, offspring of hypertensive parents had a significantly enhanced reactivity of peripheral resistance, but no differences in heart rate or blood pressure response were observed. No differences between the two groups were found in sympathetic or vagal activity during either task measured by the ratio of pre-ejection time and left ventricular ejection time, and respiratory sinus arrhythmia, respectively. CONCLUSION: Apart from a higher reactivity of SBP during the memory search task, no other indications supporting the presence of hyperadrenergic activation of the heart in early primary hypertension were found. On the contrary, the results of the present study support the hypothesis that blood pressure responses in prehypertensive subjects are characterized by enhanced vasoconstriction rather than by increased cardiac output.

Anthropometric measures, fitness and habitual physical activity in offspring of hypertensive parents. Dutch Hypertension and Offspring Study.

As part of the Dutch Hypertension and Offspring Study, subjects with contrasting risk for hypertension according to their parental history of hypertension were compared with respect to anthropometric measures and measures of fitness and physical activity. Body height, weight, two skinfolds, and blood pressure at rest were measured. Fitness was evaluated by a maximal exercise test, and habitual physical activity was assessed using a questionnaire. No differences were observed in body mass index after adjustment for slight differences in age and proportion of men between the groups (difference between groups: 0.74 kg/m2, 95% CI: -0.30, 1.78). Offspring of hypertensive parents, however, had significantly more central fat (difference between groups: 2.32 mm, 95% CI: 0.18, 4.46). No differences in fitness or physical activity were present between the two groups. The results of this study indicate a potential role for central fat in the etiology of primary hypertension. Fitness or habitual physical activity are, however, not different between groups of subjects at different risk for future hypertension.

Hemodynamic characteristics of the early phase of primary hypertension. The Dutch Hypertension and Offspring Study.

BACKGROUND: The hemodynamic characteristics of the early phase of primary hypertension are subject to debate. In particular, it remains unclear whether an increased vascular peripheral resistance or a raised cardiac output is involved as the primary hemodynamic alteration in hypertension. METHODS AND RESULTS: We studied hemodynamic characteristics and oxygen consumption in relation to 24-hour ambulatory blood pressure measurements in three groups of normotensive children with a different familial predisposition for hypertension. Selection of participants was based on parental blood pressure levels. Mean 24-hour blood pressure was higher in the offspring of two hypertensive parents compared with the offspring of two normotensive parents; there was a difference of 4.7 mm Hg (95% confidence interval [CI], 1.8-7.6) for systolic blood pressure and a difference of 4.8 mm Hg (CI, 2.3-7.3) for diastolic blood pressure. The 24-hour blood pressure pattern was consistently at a higher level for both systolic and diastolic blood pressures in the offspring of two hypertensive parents compared with the offspring of two normotensive parents. The smallest differences in blood pressure were seen at night, and the largest differences in blood pressure between the groups of offspring were seen during periods of physical activity. Echocardiographic examination combined with registration of oxygen consumption did not show a difference in cardiac index and arteriovenous oxygen difference between the study groups. However, differences in cardiac dimensions were apparent, with an increased left ventricular mass index (8.7 g/m2; CI, 2.4-15.0) in the offspring of two hypertensive parents. CONCLUSIONS: These findings do not support the existence of a hyperkinetic circulatory phase but may indicate the presence of an increased left ventricular mass in early primary hypertension.

Polymorphism of the angiotensin I converting enzyme gene is apparently not related to high blood pressure: Dutch Hypertension and Offspring Study.

OBJECTIVE: Studies in genetically hypertensive rats and their normotensive Wistar-Kyoto control rats have revealed a linkage of a chromosomal region containing the angiotensin converting enzyme (ACE) gene with blood pressure. This led to the hypothesis that ACE is a possible candidate gene for primary hypertension in humans. We defined the genotypes and allele frequencies of an insertion-deletion (I/D) polymorphism in parental couples who both had either high or low blood pressure and in their offspring. SUBJECTS: Parents (n = 111) and offspring (n = 75) with defined blood pressure status from the Dutch Hypertension and Offspring Study. METHODS: Genomic DNA was amplified by polymerase chain reaction using primers flanking the polymorphic region in intron 16 of the ACE gene. Alleles were detected on agarose gels stained with ethidium bromide. RESULTS: Allele frequencies for the D-allele were similar in parents with high (0.66) and low blood pressure (0.59) and in their offspring (0.67 and 0.69, respectively). A similar lack of difference was found with respect to the complementary I-allele. CONCLUSIONS: In the present rather large sample we failed to find a significant association between I/D polymorphism of the ACE gene and blood pressure status in subjects with high or low blood pressure and in their offspring.

Alterations in calcium metabolism in young people at risk for primary hypertension. The Dutch Hypertension and Offspring Study.

Several disturbances in calcium metabolism have been reported in primary hypertensive subjects. It is, however, not clear whether these alterations predate the development of hypertension or occur as a consequence of high blood pressure. We studied indexes of calcium metabolism in three groups of normotensive children with different familial predispositions for hypertension, based on parental blood pressure levels, with two, one, or no hypertensive parents. Plasma intact parathyroid hormone [1-84] was higher in the offspring of hypertensive parents compared with offspring of normotensive parents (difference, 0.58 pmol/L; standard error of the difference [SED], 0.24; p = 0.02). Mean serum calcium levels were slightly reduced in the offspring of two hypertensive parents (-0.019 mmol/L, SED = 0.013, p = 0.17). Plasma magnesium and phosphate levels were lower in the offspring of hypertensive parents (-0.032 mmol/L [SED = 0.016, p = 0.05] and -0.045 mmol/L [SED = 0.024, p = 0.05], respectively). Mean 1.25-dihydroxyvitamin D3 levels were similar among the groups. No differences in dietary intake of calcium, phosphate, or fiber were found. Urinary calcium excretion per 24 hours and the ratio of 24-hour urinary calcium excretion to daily calcium intake were somewhat higher in the offspring of hypertensive parents. Renal fractional excretion of calcium was similar in the offspring of two hypertensive parents, and renal fractional excretion of phosphate was lower in the offspring of two hypertensive parents compared with offspring of two normotensive parents (-1.50%, SED = 0.74, p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal hemodynamics and the renin-angiotensin-aldosterone system in normotensive subjects with hypertensive and normotensive parents.

BACKGROUND AND METHODS: The kidney is important in blood-pressure regulation, but its role in the development of essential hypertension is still subject to debate. We compared renal hemodynamics, measured in terms of the clearance of para-aminohippuric acid and inulin, and the characteristics of the renin-angiotensin-aldosterone system in three groups of normotensive subjects at different degrees of risk for hypertension: 41 subjects with two normotensive parents, 52 with one normotensive and one hypertensive parent, and 61 with two hypertensive parents. The subjects ranged in age from 7 to 32 years. RESULTS: The mean renal blood flow was lower in the subjects with two hypertensive parents than in those with two normotensive parents (mean difference [+/- SE], 198 +/- 61 ml per minute per 1.73 m2 of body-surface area; P = 0.002). Moreover, both the filtration fraction and renal vascular resistance were higher in the subjects with two hypertensive parents (filtration fraction: mean difference, 3.0 +/- 1.1 percentage points; P = 0.006; renal vascular resistance: mean difference, 2.7 +/- 0.8 mm Hg per deciliter per minute per 1.73 m2; P = 0.006). The subjects with two hypertensive parents had lower plasma concentrations of renin (mean difference, 3.3 +/- 1.6 mU per liter; P = 0.03) and aldosterone (mean difference, 111 +/- 36 pmol per liter; P = 0.003) than those with two normotensive parents. The differences could not be explained by the small differences in blood pressure between the groups. The values in the subjects with one hypertensive and one normotensive parent fell between those for the other two groups. CONCLUSIONS: Renal vasoconstriction is increased and renin and aldosterone secretion is decreased in young persons at risk for hypertension. These findings support the hypothesis that alterations in renal hemodynamics occur at an early stage in the development of familial hypertension.

[Altered sensitivity of Escherichia coli for antibiotics in the population]. / Veranderende gevoeligheid van Escherichia coli voor antibiotica in de bevolking.

Faecal carriage rates for antibiotic-resistant Escherichia coli were determined in a Dutch urban population during two periods with an interval of seven years. In the period 1978-1980 faecal samples were collected from 624 persons and in 1987 from 154 persons. E. coli was isolated from samples of 577 persons in the first period and from samples of 125 persons in the second period. The frequency of E. coli-carrying persons found with tetracycline-resistant E. coli decreased from 42% in 1978-1980 to 20% in 1987 (p less than 0.001). The frequency of persons with a predominantly tetracycline-resistant E. coli flora (greater than 50% of the E. coli flora resistant) decreased in the period 1978-1980 from 12% to 6% in 1987 (p less than 0.05). There was an increase in frequency of persons found with a predominantly ampicillin-resistant E. coli flora from 5% in 1978-1980 to 11% in 1987 (p less than 0.01). Antimicrobial resistance in the open population is a dynamic process. Data concerning an association with antibiotic consumption are mostly lacking. Further intervention studies on the influence of antibiotic policies are needed.

Determinants of blood pressure in the first decades of life.

The blood pressure (BP) in children has been studied since the beginning of this century, and in the past decade the potential association between childhood BP levels and adult hypertension has gained increasing interest. From several longitudinal studies, many of them comprising large numbers of children and youngsters, it appears that the BP of children is significantly associated with BP on follow-up measurements and that childhood BP is related to adult levels. Whether the objective is to predict future BP, or the aim is to shed light on the early pathogenesis of primary hypertension, it is of major importance to find out why BP rises in some and stays the same in others. To achieve this, characteristics need to be detected that are related to changes in BP in the first decades of life. Although not many reports on these dynamic relations are presently available, age, height, body weight, initial BP level, and a family history of hypertension have been put forward as determinants of children's BP change over time. Moreover, there are data to support the effect of dietary factors, most notably certain electrolytes, on BP regulation early in life. Also, certain hemodynamic and neural characteristics, such as changes in cardiac output and left ventricular mass, renal blood flow, and sympathetic nervous system activity, may be related to a subsequent rise in BP and future hypertension. Findings from nonexperimental and experimental studies on determinants of BP in children and youngsters will be reviewed.

Twenty-four-hour ambulatory blood pressure pattern in youngsters with a different family history of hypertension: the Dutch Hypertension and Offspring Study.

The offspring of hypertensive parents in general show higher casual blood pressure levels during adolescence than the offspring of normotensive parents. Comparative ambulatory blood pressure measurements might reveal the stability and pattern of this difference during circadian blood pressure variation. We studied the 24-h ambulatory blood pressure (Space-Labs 90202 monitor, Redmond, Washington, USA) in youngsters with two hypertensive parents (high; n = 62), with one hypertensive parent (mixed; n = 51) and with no hypertensive parent (low; n = 42). The pattern for both systolic and diastolic blood pressure in the three groups ran parallel, with the high group continuously at a higher level. A clear difference in systolic blood pressure was observed during the day period (high minus low: 5.4 mmHg; 95% confidence range 2.5-8.3). Our data show that offspring of hypertensive parents differ in ambulatory blood pressure levels, but not in the circadian pattern, from the offspring of normotensive parents.

Similar plasma atrial natriuretic factor levels in children and young adults with a high and low probability of developing hypertension: the Dutch Hypertension and Offspring Study.

The role of atrial natriuretic factor (ANF) in the genesis of primary hypertension is not clear. However, a natriuretic and blood pressure lowering effect has been observed after infusion of ANF. Therefore, subjects at risk of future hypertension might be deficient in ANF or less responsive to it. To address this question we studied ANF, sodium excretion and blood pressure in 180 young normotensive people with different probabilities of developing hypertension later in life. The 180 subjects had either two, one or no hypertensive parents. Sixty-nine offspring had a high, 58 an intermediate and 53 a small probability of developing hypertension ('high', 'mixed' and 'low' groups). Mean plasma levels of ANF did not differ among the three groups of offspring. A negative association was found between ANF and diastolic blood pressure, being most pronounced in the low-risk group. The similar levels of plasma ANF in these groups suggest that ANF is not directly related to the development of high blood pressure.

Change in blood pressure in offspring of parents with high or low blood pressure: the Dutch Hypertension and Offspring Study.

A family history of hypertension is an important predictor of high blood pressure. We investigated the question of whether this predisposition affects the level and change of blood pressure early in life, and in particular, at what age the familial aggregation of blood pressure occurs. Blood pressure and related characteristics were studied in children whose parents both had relatively high blood pressure ('high') and the results were compared with those from children whose parents both had a relatively low blood pressure ('low') and with children with one parent high and the other parent low ('mixed'). At the age of 8 years there were no clear differences in pressure but at the age of 20 years there was a difference of 7 mmHg for both systolic and diastolic pressure between the high- and low-risk offspring. These findings suggest that the magnitude of familial aggregation of blood pressure increases during childhood and adolescence.