Genetic and environmental factors in orientation anisotropy: a field study in the British Isles

Visual acuity for the detection of gratings at four orientations was measured for groups of ten boys and ten girls aged five to seven years, from the following four populations: Scots in Glasgow, Pakistanis in Glasgow, Gaels in Stornoway (Outer Hebrides) and East Anglians in Littleport (Cambridgeshire fenlands). The Glaswegians, both Scottish and Pakistani, showed the normal pattern of anisotropy, with poorest acuity for oblique orientations; the East Anglians showed no significant anisotropy; while the Gaels were unusual in showing poorest horizontal acuity. A group of fourteen Pakistani children in Stornoway differed slightly from a matched group of Gaels. The group differences bore little relation to the visual environments, and were probably due to genetic or cultural factors. The relatively poor horizontal acuity of the Gaels was not correlated with astigmatism. Sex differences were also found, with the boys showing higher mean acuity and a higher ratio between vertical and oblique acuity.     

Type A behavior, family history of hypertension, and cardiovascular responsivity among black women

The purpose of this study was to determine the effects of Type A behavior and family history of hypertension on cardiovascular reactivity to mental stress in a group of employed black women. Measures of heart rate and of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were taken at rest, during a mental arithmetic task, and during the Type A Structured Interview (SI). Results indicated that the Type A behavior pattern was associated with SBP and DBP hyperresponsivity during the SI but not during mental arithmetic. Additionally, certain speech components of the Type A pattern, as well as features of the potential-for-hostility component, were also related to cardiovascular responses during the SI. Family history of hypertension did not influence the cardiovascular parameters either alone or in combination with Type A behavior. The results suggest that many of the cardiovascular response characteristics of the Type A pattern that have been observed in predominantly white samples also hold true for blacks. Replication of these findings with other subgroups of blacks, such as young females and middle-aged males, will help document the generality of these findings within the black population.     

Cardiovascular reactivity to psychological stress in aerobically trained versus untrained mild hypertensives and normotensives

Cardiovascular reactivity to video game and mental arithmetic stressors was compared among three groups of men: aerobically trained mild hypertensives, untrained mild hypertensives, and a comparison group of untrained normotensives. Relative to the untrained hypertensives, the trained hypertensives reacted to the video game with marginally smaller systolic blood pressure and diastolic blood pressure, but there were no significant differences between these groups in reactivity during the mental arithmetic task. Comparisons between each hypertensive group and the normotensive group showed that blood pressure (BP) reactivity of normotensives during the video game was generally similar to that of trained hypertensives but smaller than that of untrained hypertensives. These results indicate that aerobic training, which has been found to reduce resting BP in mild hypertensives, may also exert a favorable impact in reducing cardiovascular reactivity of hypertensives during some stressful situations.