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The postantibiotic effects (PAEs) OF 16 antibiotics or antibiotic combinations currently used against Burkholderia (Pseudomonas) pseudomallei were determined. The beta-lactams had zero PAEs, while the carbapenems and ciprofloxacin induced median PAEs of 1 and 5 h, respectively. These results emphasize the need to maintain antibiotic levels above inhibitory concentrations in blood throughout the dosing interval in cases of severe melioidosis.
Males commonly face a trade-off between investment in offspring care and time spent seeking additional breeding opportunities. Although this trade-off is central to our understanding of the evolution of male parental care, it has been largely ignored by studies of male alloparental care in cooperative societies, where male helpers could face a similar problem. We investigated whether male helpers in cooperative societies of meerkats Suricata suricatta trade off their cooperative contributions to pup feeding against extraterritorial prospecting for mating and dispersal opportunities. Not only did male helpers spend extended periods away from the group during pup care periods, but those that spent most time prospecting also contributed least to pup feeding when present in the group. Regular prospectors lost the most weight over the pup-feeding period and male testosterone levels increased in association with prospecting. As both reduced body condition and elevated testosterone have been shown to compromise the expression of offspring care, these findings provide likely explanations for the reduced pup-feeding rates of regular prospectors. Despite their lapses in contributions to cooperative activities, we found no evidence for punishment of prospectors by other group members, suggesting that helpers are able to adjust their contributions according to their own optima. These findings reveal that male helpers in cooperative species can face similar trade-offs to male parents in noncooperative species, between investment in offspring care and alternative fitness-maximizing tactics such as prospecting. We discuss the broader implications of this work for our understanding of both individual variation and sex differences in contributions to cooperative behaviour.
Journal Article Foreword Get access Nicholas J. White Nicholas J. White Search for other works by this author on: Oxford Academic PubMed Google Scholar Transactions of The Royal Society of Tropical Medicine and Hygiene, Volume 88, Issue Supplement_1, June 1994, Page 1, https://doi.org/10.1016/0035-9203(94)90458-8 Published: 01 June 1994
Elastase is one of a class of serine proteinases (Hartley, 1960) which also includes trypsin, chymotrypsin-A and chymotrypsin-B, enzymes which all exhibit a common catalytic mechanism for the hydrolysis of peptide bonds in dietary protein, but which differ markedly in their specificity towards the amino acid residues forming those bonds. Elastase is synthesized in the acinar tissue of mammalian pancreas as an inactive zymogen, proelastase, which on entering the duodenum is activated by the tryptic cleavage of a single peptide bond, releasing a small activation peptide (Gertler and Birk, 1970) to yield the active enzyme, a single polypeptide chain of 240 amino acid residues containing four disulfide bridges (Shotton and Hartley, 1970).
Intravenous insulin tolerance tests and thyrotropin-releasing hormone (T.R.H.) stimulation tests were performed in nine massively obese women and six lean female controls and the prolactin, growth hormone, and cortisol responses were measured. A combined pituitary function test (insulin, T.R.H., and gonadotropin-releasing hormone) was performed in eleven other massively obese women. In the obese women to whom insulin was given separately there was no prolactin release, and growth hormone and cortisol responses were impaired. T.R.H. stimulation produced a prolactin response which was subnormal. These changes were not apparent in the obese women in whom a combined pituitary function test was performed. The results suggest an alteration of hypothalamic function in massive obesity.
No abstract is provided for this article.
No abstract is provided for this article.
All antimalarial drugs developed so far have eventually succumbed to resistance. There is a general belief that the more people that are exposed to an antimalarial drug, the more likely it is that resistance will emerge. Mass drug administration (MDA) is therefore considered a potent cause of antimalarial drug resistance. In this Personal View, I discuss the circumstances under which antimalarial MDA increases or decreases the risk of resistance. It is the total number of parasites exposed and their individual probabilities of survival and spread that determine the risk, not the number of people that contain them. In malaria-endemic areas, a substantial proportion of the community carries malaria parasites in their blood without being ill. Although many more people have asymptomatic than symptomatic malaria at any time, their parasite burdens are several orders of magnitude lower, and their host defence mechanisms are substantially more effective. Symptomatic infections with high parasite numbers are the most likely source of resistance emergence, so effective mass treatment that reduces the number of symptomatic cases of malaria and its transmission can reduce the threat of antimalarial resistance emerging and spreading in treated populations.
Red cell concentrations of quinine were measured in cerebral malaria and in uncomplicated falciparum malaria both in the acute stage and 1 month after recovery. Red cell quinine elimination half times were significantly shorter than the corresponding plasma half times in cerebral malaria and convalescent uncomplicated cases (P < 0.001), but not in acute uncomplicated cases (P = 0.12). The ratio of red cell:plasma concentration fell progressively from the 2nd day (0.49) to the 6th day (0.26) of treatment. On admission this ratio was positively correlated with the blood parasite count (P = 0.02). Red cell quinine concentration may be relevant to the assessment of drug resistance, and to the design of treatment regimens.
Rosetting forces are believed to be an important contributor to the microcirculatory obstruction that occurs in malaria caused by Plasmodium falciparum. In this study, rosettes of erythrocytes from cultures of this parasite were suspended in different media and exposed to shear stresses corresponding to those encountered on the arterial and venous sides of the human circulation. The rosettes formed by infected erythrocytes in malaria culture medium containing 10% AB serum were disrupted easily (approximately 50% being broken) when exposed to very low shear stresses of < 0.5 Pa. However, use of higher concentrations of serum strengthened the rosetting binding forces considerably. Suspension of rosettes in a viscous colloid (e.g. dextran) increased the adherence forces between infected and uninfected red cells. The results indicate that rosettes do resist the physiological shear forces that are encountered in the venular side of the circulation and could thus contribute to microvascular obstruction in falciparum malaria.
Conference Abstract| September 01 1982 Prolactin Secretion in Massive Obesity: Further Evidence for a Disorder of Hypothalamic Function in Some Obese Women P.G. Kopelman; P.G. Kopelman 1Dept of Metabolism and Endocrinology, The London Hospital E1 1BB Search for other works by this author on: This Site PubMed Google Scholar N. White; N. White *Dept of Endocrinology, Chelsea Hospital for Women London SW8 Search for other works by this author on: This Site PubMed Google Scholar Wang Hang-Zheng; Wang Hang-Zheng *Dept of Endocrinology, Chelsea Hospital for Women London SW8 Search for other works by this author on: This Site PubMed Google Scholar S.L. Jeffcoate S.L. Jeffcoate *Dept of Endocrinology, Chelsea Hospital for Women London SW8 Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (1982) 63 (3): 10P. https://doi.org/10.1042/cs063010P Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation P.G. Kopelman, N. White, Wang Hang-Zheng, S.L. Jeffcoate; Prolactin Secretion in Massive Obesity: Further Evidence for a Disorder of Hypothalamic Function in Some Obese Women. Clin Sci (Lond) 1 September 1982; 63 (3): 10P. doi: https://doi.org/10.1042/cs063010P Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 1982 The Biochemical Society and the Medical Research Society1982 Article PDF first page preview Close Modal You do not currently have access to this content.
