Comparative analyses suggest that monogamous breeding systems evolved in mammals where feeding competition reduces range overlap between breeding females, preventing males from guarding more than one female at a time (1). In contrast, a recent analysis for primates suggests that monogamy evolved as a form of paternal care that reduces the risk of male infanticide (2). Here we reexamine the distribution of monogamy in primates and attempt to explain the contrasting results of the two analyses. Methods and detailed results are described in supplementary material (3).
Hypoglycaemia, defined as a plasma glucose concentration below 2·2 mmol/l, developed in 15 of 47 prospectively studied Gambian children with severe chloroquine-sensitive falciparum malaria. 5 of these hypoglycaemic children died compared with 1 in the normoglycaemic group (p = 0·02). In contrast to previous observations in quinine-treated adults, in whom hypoglycaemia was associated with hyperinsulinaemia, plasma concentrations of insulin were appropriately low and plasma ketones were high. Raised plasma concentrations of lactate and alanine suggested impairment of hepatic gluconeogenesis. In African children, hypoglycaemia is an important and treatable manifestation of severe malaria and is unrelated to antimalarial treatment.
Abstract The current decline of the highly endangered African wild dog ( Lycaon pictus ) may be partly due to the population dynamics induced by their social system. African wild dogs are obligate co‐operators, and their need for helpers could generate inverse density dependence at the pack level. We show, through a mathematical model, that this can create an Allee effect, leading to a lower population size and a higher risk of population extinction, compared to populations with direct density dependence. This is due to three different processes. All three processes can increase population extinction individually and probably occur simultaneously in African wild dogs. First, inverse density dependence causes significantly higher rates of pack extinction. Second, it also increases the probability of failure to colonize territories by founders. Third, the Allee effect at the pack level (with a critical number of individuals), generates an Allee effect at the population level (with a critical number of packs). These three processes are likely to apply to other obligate co‐operative breeders. Furthermore, our results suggest that habitat fragmentation and destruction, as well as increased human pressure, increase the effects of inverse density dependence. Direct and indirect anthropogenic effects may thus be more detrimental to obligate co‐operative breeders than to other species.
No abstract is provided for this article.
To investigate the prevalence of cardiac abnormalities in osteogenesis imperfecta we performed a clinical and echocardiographic study on 20 patients. One patient had aortic regurgitation, 13 had soft late apical systolic murmurs (without significant mitral regurgitation), and seven had systemic hypertension. In only one patient was there echocardiographic evidence of mitral valve prolapse. The aortic root diameter exceeded the normal range in six patients, two of whom were hypertensive. The overall mean value (± 1 S.D.) in the 16 patients without marked skeletal deformity was 2.02 ± 0.33 cm/m2. The echocardiographic appearances suggested that the left-sided valve cusps were thin, and in 13 patients the aortic valve leaflets showed a coarse systolic flutter.
The enantiomers of the 8-aminoquinoline anti-malarial primaquine have different pharmacological properties. Development of an analytical method for simultaneous quantification of the enantiomers of primaquine and its metabolite, carboxyprimaquine, will support clinical pharmacometric assessments.A simple and sensitive method consisting of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed for simultaneous and enantiospecific determination of primaquine and its metabolite, carboxyprimaquine, in human plasma. Stable isotopes were used as internal standards to compensate for potential interference and matrix effects. Plasma samples (100 µL) were precipitated with 1% formic acid in acetonitrile followed by phospholipid removal solid phase extraction. Primaquine and carboxyprimaquine enantiomers were separated on a Chiralcel OD-3R (150 mm × 4.6 mm; I.D. 3 μm) column using a LC gradient mode. For separation of racemic primaquine and carboxyprimaquine, the LC method was modified and validated using a reverse phase column (Hypersil Gold 100 mm × 4.6 mm; I.D. 3 µm) and a mobile phase composed of 10 mM ammonium acetate buffer, pH 3.5 and acetonitrile in the isocratic mode. Method validation was performed according to regulatory guidelines.The calibration range was set to 0.571-260 ng/mL and 2.44-2,500 ng/mL for primaquine and carboxyprimaquine enantiomers, respectively, resulting in a correlation coefficient (r2) ≥ 0.0998 for all calibration curves. The intra- and inter-day assay precisions were < 10% and the accuracy was between 94.7 to 103% for all enantiomers of primaquine and carboxyprimaquine. The enantiospecific method was also modified and validated to quantify racemic primaquine and carboxyprimaquine, reducing the total run time from 30 to 8 min. The inter-, intra-day assay precision of the racemic quantification method was < 15%. The absolute recoveries of primaquine and carboxyprimaquine were between 70 and 80%. Stability was demonstrated for up to 2 years in - 80 °C. Both the enantiomeric and racemic LC-MS/MS methods were successfully implemented in pharmacokinetic studies in healthy volunteers.Simple, sensitive and accurate LC-MS/MS methods for the quantification of enantiomeric and racemic primaquine and carboxyprimaquine in human plasma were validated successfully and implemented in clinical routine drug analysis.
No abstract is provided for this article.
An open randomised trial was conducted to compare ceftazidime (120 mg/kg/day) with "conventional therapy" (chloramphenicol 100 mg/kg/day, doxycycline 4 mg/kg/day, trimethoprim 10 mg/kg/day, and sulphamethoxazole 50 mg/kg/day) in the treatment of severe melioidosis. A paired restricted sequential trial designed to detect a reduction in mortality from 80 to 40% in culture-positive patients surviving > 48 hours was stopped after 22 months. Of the 161 patients entered into the study, 65 had bacteriologically confirmed melioidosis and 54 of these were septicaemic. Ceftazidime treatment was associated with a 50% (95% CI 19-81%) lower overall mortality than conventional treatment (74% vs 37%; p=0·009) and should now become the treatment of choice for severe melioidosis.
Gestation and subsequent lactation are energetically costly life history events for mammalian females. We used longitudinal delta15N data from hair samples from offspring and their mothers to explore lactation patterns in a small cooperative mammal, the meerkat (Suricata suricatta). Lactation enriched hair from meerkat offspring in 15N compared with that of their mothers, and this enrichment gradually declined after weaning. Although the observed peak enrichment of approximately 1 per thousand was substantially below the predicted levels of trophic enrichment in capital versus income breeders, we suggest that our results reflect an income breeding tactic in this species. Our study supports the notion that delta15N analyses can be a useful tool to investigate lactation schedules in mammals. However, reliable conclusions from 15N data regarding the nutritional tactics of mammalian females during reproduction may be limited by our scant understanding of the effects of various physiological variables on isotope assimilation.
