pituitrin and Malaria

Signatures of recent positive selection often overlap across human populations, but the question of how often these overlaps represent a single ancestral event remains unresolved. If a single selective event spread across many populations, the same sweeping haplotype should appear in each population and the selective pressure could be common across populations and environments. Identifying such shared selective events could identify genomic loci and human traits important in recent history across the globe. In addition, genomic annotations that recently became available could help attach these signatures to a potential gene and molecular phenotype selected across populations. Here, we present a catalogue of selective sweeps in humans, and identify those that overlap and share a sweeping haplotype. We connect these sweep overlaps with potential biological mechanisms at several loci, including potential new sites of adaptive introgression, the glycophorin locus associated with malarial resistance and the alcohol dehydrogenase cluster associated with alcohol dependency.

Topics: Alcoholism; Glycophorins; Haplotypes; Humans; Malaria; Neurophysins; Protein Precursors; Selection, Genetic; Vasopressins

Although hyponatremia occurs in most patients with severe malaria, its pathogenesis, prognostic significance, and optimal management have not been established. Clinical and biochemical data were prospectively collected from 171 consecutive Bangladeshi adults with severe malaria. On admission, 57% of patients were hyponatremic. Plasma sodium and Glasgow Coma Score were inversely related (r(s) = -0.36, P < 0.0001). Plasma antidiuretic hormone concentrations were similar in hyponatremic and normonatremic patients (median, range: 6.1, 2.3-85.3 versus 32.7, 3.0-56.4 pmol/L; P = 0.19). Mortality was lower in hyponatremic than normonatremic patients (31.6% versus 51.4%; odds ratio [95% confidence interval]: 0.44 [0.23-0.82]; P = 0.01 by univariate analysis). Plasma sodium normalized with crystalloid rehydration from (median, range) 127 (123-140) mmol/L on admission to 136 (128-149) mmol/L at 24 hours (P = 0.01). Hyponatremia in adults with severe malaria is common and associated with preserved consciousness and decreased mortality. It likely reflects continued oral hypotonic fluid intake in the setting of hypovolemia and requires no therapy beyond rehydration.

Topics: Acetylcysteine; Adolescent; Adult; Aged; Bangladesh; Female; Glasgow Coma Scale; Humans; Hyponatremia; Hypovolemia; Malaria; Male; Middle Aged; Seasons; Sodium; Vasopressins; Young Adult

Vasopressin levels, together with plasma and urinary electrolytes, were measured in the acute and convalescent stages of 17 patients with malaria and 11 patients with other febrile illnesses. There was a significantly lower serum sodium in the acute stages of both groups (p less than 0.01 and p less than 0.02). There was no significant difference between the malaria and control groups. There were no significant changes in the vasopressin levels, although one patient with malaria showed evidence of inappropriate vasopressin secretion which returned to normal after treatment. This study suggests the mild hyponatraemia sometimes seen in the acute stages of malaria is not related to inappropriate secretion of vasopressin, although this condition may be of importance in more severe cases of hyponatraemia.

Topics: Adolescent; Adult; Animals; Electrolytes; Female; Humans; Hyponatremia; Inappropriate ADH Syndrome; Malaria; Male; Middle Aged; Plasmodium falciparum; Vasopressins

Topics: Aminoisobutyric Acids; Animals; Carbon Isotopes; Depression, Chemical; Haplorhini; Intestinal Absorption; Liver Circulation; Malaria; Phenoxybenzamine; Vasopressins; Xylose