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S P McKeown

Publications and source records attributed to S P McKeown.

5 recordsLinked to original sources
PubMed1997

Preliminary evidence of linkage of salt sensitivity in black Americans at the beta 2-adrenergic receptor locus.

Salt sensitivity is a heritable trait that is a hallmark of hypertension in black Americans. Genes encoding adrenergic receptors are candidate loci for the inheritance of this hypertension-related trait because of the role of these receptors in the regulation of renal sodium excretion and vascular tone. We performed this study to determine whether these loci are responsible for some of the phenotypic variation in salt sensitivity. Hypertensive black American probands were ascertained, followed by sequential ascertainment of adult sib pairs among the first-, second- and third-degree relatives of the proband. Both hypertensive and normotensive siblings were tested for salt sensitivity by an intravenous sodium-loading, lasix volume-depletion protocol. Genotyping was performed with restriction fragment length polymorphisms in genomic DNA probed with clones containing the beta 2- and alpha 2c10-adrenergic receptor genes. A total of 109 sib pairs was evaluated. Salt sensitivity was defined as the change in blood pressure in each individual, comparing the sodium-loaded with the volume-depleted state. Systolic pressure decreased by an average of 9.0 +/- 9%, diastolic pressure by 1.5 +/- 11%, and mean arterial pressure by 5.0 +/- 9%. Neither blood pressure nor salt sensitivity was linked at the alpha 2c10-adrenergic receptor locus. No evidence suggested that systolic salt sensitivity and baseline blood pressure were linked at the beta 2-adrenergic receptor locus. Model-independent sib pair linkage analysis suggested that diastolic blood pressure response to sodium loading/volume depletion is linked at the beta 2-adrenergic receptor locus (P < .006). Evidence for linkage was significant at the .05 level after adjustment for the number of phenotypic traits examined.

Adult↗
PubMed1996

Heritability of salt sensitivity in black Americans.

Salt sensitivity is defined as a change in blood pressure in response to changes in salt and water homeostasis. Found in 73% of hypertensive and 36% of normotensive blacks, it is generally considered a hallmark of hypertension in blacks. The higher prevalence of salt sensitivity in blacks compared with whites suggests a genetic influence on this trait, but there is little direct evidence of heritability. We determined the extent to which salt sensitivity is correlated in black families and estimated the heritability of this phenotype. Black families were recruited through a hypertensive proband. Both hypertensive and normotensive adults were phenotyped with respect to salt sensitivity with an intravenous sodium-loading, furosemide volume-depletion protocol. Salt sensitivity was defined as the difference between sodium-loaded and volume-depleted blood pressure. We enrolled 20 families, comprising 30 parent-offspring pairs and 115 adult sibling pairs. Age-adjusted familial correlations ranged from .33 to .44, .19 to .37, and .12 to .21 for mean arterial and systolic and diastolic pressure responses to the salt sensitivity maneuver, respectively. Corresponding heritability estimates were 0.26 to 0.84, 0.26 to 0.74, and 0.004 to 0.24, respectively. These data strongly suggest a heritable component of salt sensitivity.

Adult↗
PubMed1989

Alcoholism, alcohol and attempted suicide.

Attempted suicide patients referred to a general hospital over a 10 year period were studied with regard to alcoholism and drinking in association with suicide attempts. Alcoholism was diagnosed in 7.9% of patients (14.6% of males and 4.2% females), and this diagnosis became proportionately more common in both sexes during the study period. However, only male alcoholic attempters showed an increase in absolute numbers during the study period, the increase in the proportion of females diagnosed as alcoholic being due to a decline in attempts by non-alcoholics. Particularly high rates of alcoholism were found in the unemployed of both sexes and in housewives. Alcoholic attempters were at greatly increased risk of making repeat attempts. Alcohol consumption shortly before a suicide attempt and as part of the act was extremely common, especially among alcoholics. In addition to increasing the likelihood of an attempt, alcohol may add considerably to the danger of overdoses. Careful investigation of drinking patterns should be an integral part of the assessment of all attempted suicide patients, and there should be close liaison between general hospital services for such patients and local alcoholism treatment services.

Adolescent↗