Assumed White Blood Cell Count of 8,000 Cells/μL Overestimates Malaria Parasite Density in the Brazilian Amazon

Quantification of parasite density is an important component in the diagnosis of malaria infection. The accuracy of this estimation varies according to the method used. The aim of this study was to assess the agreement between the parasite density values obtained with the assumed value of 8,000 cells/μL and the automated WBC count. Moreover, the same comparative analysis was carried out for other assumed values of WBCs. The study was carried out in Brazil with 403 malaria patients who were infected in different endemic areas of the Brazilian Amazon. The use of a fixed WBC count of 8,000 cells/μL to quantify parasite density in malaria patients led to overestimated parasitemia and resulted in low reliability when compared to the automated WBC count. Assumed values ranging between 5,000 and 6,000 cells/μL, and 5,500 cells/μL in particular, showed higher reliability and more similar values of parasite density when compared between the 2 methods. The findings show that assumed WBC count of 5,500 cells/μL could lead to a more accurate estimation of parasite density for malaria patients in this endemic region.     

Effects of Work and Orcadian Rhythm on Bus Drivers' Oral Temperature

The results described in this paper originate from a research project aiming at the development of a useful measuring instrument which can demonstrate the effect of work and work circumstances on the task performer. Among other physiological (and psychometric) variables, oral temperature data were obtained from eight younger and eight older bus drivers working in various shifts. Measurements were performed in an experimental design under standardized conditions in a mobile laboratory before starting, during some rest intervals, and after finishing work. The same measurements were performed on the bus drivers in a control condition at corresponding times on a day off. The results indicated that only during the working days a temperature pattern could be detected resembling the data found in the literature (low in the morning, a maximum in the late afternoon, then a decline). No clear pattern was discernible on work-free days. On working days the mean oral temperature values were significantly higher at corresponding hours of the day. Upward deviations of the temperature pattern were found before starting work (but also at the beginning of the day off), while lower values were obtained after finishing work (especially in the shifts starting in the morning). These results might be interpreted in terms of interaction between circadian rhythm and activating and de-activating tendencies connected with (structured) daily activities.     

Effects of 17-β-estradiol treatment of female zebra finches on offspring sex ratio and survival

Treatment of female zebra finches (Taeniopygia guttata) with 17-beta-estradiol leads to a female-biased sex ratio in their offspring at the age of independence [Horm. Behav. 35 (1999) 135]. It is unclear whether this is due to a bias of the primary sex ratio or to sex-specific survival. We replicated this experiment and found again a significantly higher total number of daughters than sons at independence in the estradiol-treated group. This was due to higher embryonic survival of daughters compared with sons in the estradiol-treated group and the reverse in the control group. There was no effect of the hormone treatment on the primary sex ratio. Treatment with 17-beta-estradiol led to a significantly shorter hatching time and to heavier offspring at day 7 after hatching. This weight was correlated with maternal plasma estradiol levels on the day of the first egg, which were significantly higher in the estradiol-treated group than in the control group. The results do not support the idea that maternal estradiol levels influence the primary sex ratio. They indicate that maternal estradiol differentially affects survival of sons and daughters via an influence on the embryonic environment, possibly enhancing offspring growth.     

Polymorphism at the apical membrane antigen 1 locus reflects the world population history of <Emphasis Type="Italic">Plasmodium vivax</Emphasis>

Background  

In malaria parasites (genus Plasmodium), ama-1 is a highly polymorphic locus encoding the Apical Membrane Protein-1, and there is evidence that the polymorphism at this locus is selectively maintained. We tested the hypothesis that polymorphism at the ama-1 locus reflects population history in Plasmodium vivax, which is believed to have originated in Southeast Asia and is widely geographically distributed. In particular, we tested for a signature of the introduction of P. vivax into the New World at the time of the European conquest and African slave trade and subsequent population expansion.     

Acrylate end-capped poly(ester-carbonate) and poly(ether-ester)s for polymer-on-multielectrode array devices: synthesis, photocuring, and biocompatibility

Polymeric materials based on epsilon-caprolactone (CL), 1,5-dioxepan-2-one (DXO), and trimethylene carbonate (TMC) were prepared and evaluated as possible candidates for polymer-on-multielectrode (PoM) applications. CL was copolymerized with either DXO or TMC in the presence of the diol initiator 1,4-benzenedimethanol (BDM). The ring-opening polymerization experiments, carried out in bulk and using tin(II) catalysis, yielded the desired low molecular weight random copolymer diols, as evidenced by NMR, IR, MALDI-ToF MS, and DSC techniques. Upon reaction with acryloyl chloride, the corresponding diacrylate end-capped copolymers were obtained. The latter were characterized by NMR and IR spectroscopy, and their photocross-linking (in the presence of a UV initiator) was followed by ATR-FTIR spectroscopy. Transparent and soft thin films of the copoly(ether-ester) and copoly(ester-carbonate) diacrylates were prepared and cured under UV irradiation. The resulting polymeric films showed good biocompatibility properties as far as in vitro neural stem cells proliferation and differentiation to neurons and astrocytes are concerned. Noteworthy are the beneficial effects obtained upon preconditioning the copolymers by means of the cell-culture medium and the excellent properties shown particularly by the CL-TMC copolymer. Moreover, preliminary results show that microchannel formation by photocuring is possible with the synthesized polymers.     

Female plumage spottiness signals parasite resistance in the barn owl (Tyto alba)

The hypothesis that extravagant ornaments signal parasite resistancehas received support in several species for ornamented malesbut more rarely for ornamented females. However, recent theorieshave proposed that females should often be under sexual selection,and therefore females may signal the heritable capacity toresist parasites. We investigated this hypothesis in the sociallymonogamous barn owl, Tyto alba, in which females exhibit on average more and larger black spots on the plumage than males,and in which males were suggested to choose a mate with respectto female plumage spottiness. We hypothesized that the proportionof the plumage surface covered by black spots signals parasiteresistance. In line with this hypothesis, we found that theectoparasitic fly, Carnus hemapterus, was less abundant onyoung raised by more heavily spotted females and those flieswere less fecund. In an experiment, where entire clutches werecross-fostered between nests, we found that the fecundity ofthe flies collected on nestlings was negatively correlatedwith the genetic mother's plumage spottiness. These resultssuggest that the ability to resist parasites covaries with theextent of female plumage spottiness. Among females collecteddead along roads, those with a lot of black spots had a smallbursa of Fabricius. Given that parasites trigger the developmentof this immune organ, this observation further suggests thatmore spotted females are usually less parasitized. The same analyses performed on male plumage spottiness all provided non-significant results. To our knowledge, this study is the first one showingthat a heritable secondary sexual characteristics displayedby females reflects parasite resistance.     

Structural characterization of bacteriophage M13 solubilization by amphiphiles

The structural properties of bacteriophage M13 during disassembly were studied in different membrane model systems, composed of a homologue series of the detergents sodium octyl sulfate, sodium decyl sulfate, and sodium dodecyl sulfate. The structural changes during phage disruption were monitored by spin-labeled electron spin resonance (ESR) and circular dichroism spectroscopy. For the purpose of ESR spectroscopy the major coat protein mutants V31C and G38C were site-directed spin labeled in the intact phage particle. These mutants were selected because the mutated sites are located in the hydrophobic part of the protein, and provide good reporting locations for phage integrity. All amphiphiles studied were capable of phage disruption. However, no significant phage disruption was detected below the critical micelle concentration of the amphiphile used. Based on this finding and the linear dependence of phage disruption by amphiphiles on the phage concentration, it is suggested that the solubilization of the proteins of the phage coat by amphiphiles starts with an attachment to and penetration of amphiphile molecules into the phage particle. The amphiphile concentration in the phage increases in proportion to the amphiphile concentration in the aqueous phase. Incorporation of the amphiphile in the phage particle is accompanied with a change in local mobility of the spin-labeled part of the coat protein and its secondary structure. With increasing the amphiphile concentration in the phage particle, a concentration is reached where the concentration of the amphiphile in the aqueous phase is around its critical micelle concentration. A further increase in amphiphile concentration results in massive phage disruption. Phage disruption by amphiphiles appears to be dependent on the phage coat mutations. It is concluded that phage disruption is dependent on a hydrophobic effect, since phage solubilization could significantly be increased by keeping the hydrophilic part of the amphiphile constant, while increasing its hydrophobic part.     

Grunge, related to human Atrophin-like proteins, has multiple functions in Drosophila development

We have carried out a genetic screen designed to isolate regulators of teashirt expression. One of these regulators is the Grunge gene, which encodes a protein with motifs found in human arginine-glutamic acid dipeptide repeat, Metastasis-associated-like and Atrophin-1 proteins. Grunge is the only Atrophin-like protein in Drosophila, whereas several exist in humans. We provide evidence that Grunge is required for the proper regulation of teashirt but also has multiple activities in fly development. First, Grunge is crucial for correct segmentation during embryogenesis via a failure in the repression of at least four segmentation genes known to regulate teashirt. Second, Grunge acts positively to regulate teashirt expression in proximoventral parts of the leg. Grunge has other regulatory functions in the leg, including the patterning of ventral parts along the entire proximodistal axis and the proper spacing of bristles in all regions.     

Clinical and angiographic results with the beStent: the Registry for Optimal beStent Evaluation (ROSE) trial

BACKGROUND: Although safety and efficacy of the beStent (Medtronic Inc., Santa Rosa, CA, USA) have been described, the long-term angiographic and clinical outcomes have yet to be investigated. The ROSE (Registry for Optimal beStent Evaluation) trial was designed to assess the procedural safety of single 15 mm beStent implantation, and the six-month angiographic and 12-month clinical outcomes of patients treated with this novel coronary stent. METHODS: Patients with angina and a single de novo lesion in a native coronary artery of >/=2.75 mm diameter were included in this multicenter, prospective, observational trial. Clinical follow-up was obtained at one, six and 12 months. Angiography was performed before and after the stent implantation and at six months. The primary end-point included major adverse cardiac events (death, myocardial infarction and target lesion revascularization), major bleeding complications, and thrombotic occlusions at one-month follow-up. Secondary end-points were major cardiac-event-free survival at six- and 12-month follow-up and angiographic restenosis at six months. A total of 120 patients (80% male, mean age 58.6 +/- 10.6 years) with stable (48%) or unstable (44%) angina pectoris were allocated. The target vessel reference diameter pre-procedure was 2.85 +/- 0.52 mm. RESULTS: Minimal lumen diameter pre/post and at follow-up was 0.97 +/- 0.28 mm, 2.53 +/- 0.40 mm and 1.86 +/- 0.63 mm, respectively. Restenosis rate according to the >50% diameter stenosis criterion at six-month follow-up was 21.5%. At 12 months, the event-free survival rate was 75% (no deaths, two Q-wave and seven non-Q-wave infarctions, five bypass surgery interventions and 16 target lesion revascularizations), whilst 87% of the patients were free of angina pectoris. CONCLUSION: Despite the relatively high percentage of small vessels, the outcome of the ROSE trial is comparable to those observed in previous stent trials, indicating that the coronary beStent is safe and effective as a primary device for the treatment of native coronary artery lesions in patients with (un)stable angina pectoris.     

Consequences of sex-specific growth on sibling competition in black-headed gulls: a sexually-size dimorphic species with scramble competition

Biased mortality of the larger sex during the early developmental period has been reported for a number of size-dimorphic bird species. This can partly be explained by the fact that growing to larger size renders the larger sex more vulnerable to food shortage. However, since sibling rivalry is often size-dependent, chicks of the larger sex should have a competitive advantage. This raises the question as to why the larger sex does not always benefit from its size in sibling competition. We studied sibling competition in the black-headed gull (Larus ridibundus), a sexually-size dimorphic species with male-biased mortality. We manipulated the natural brood sex ratio and placed one male chick in direct competition with one female chick while concurrently controlling for differences in age, size and laying order. Male chicks outgrew their female siblings by 15% in asymptotic body mass and did not suffer from enhanced mortality. Female chicks tended to be more alert when the parents returned to the nest and were more persistent in gull-typical begging displays. Females were more likely to get the first food item, but they did not get more food, possibly due to a size-mediated dominance over the non-monopolizable regurgitated food. Thus, it is unlikely that sex differences in competitiveness significantly contribute to male-biased mortality in black-headed gulls. The previously reported male-biased mortality is more likely due to a disadvantage of a higher food demand and a higher sensitivity towards low egg quality, as has been shown in previous studies.