Mating avoidance in female olive baboons (Papio anubis) infected by Treponema pallidum.

Sexually transmitted infections (STIs) are ubiquitous within wild animal populations, yet it remains largely unknown whether animals evolved behavioral avoidance mechanisms in response to STI acquisition. We investigated the mating behavior of a wild population of olive baboons (Papio anubis) infected by the bacterium Treponema pallidum. This pathogen causes highly conspicuous genital ulcerations in males and females, which signal infectious individuals. We analyzed data on 876 mating attempts and associated acceptance or rejection responses in a group of about 170 baboons. Our findings indicate that females are more likely to avoid copulation if either the mating partner or females themselves have ulcerated genitals. We suggest that this outcome is linked to the overall higher choosiness and infection-risk susceptibility typically exhibited by females. Our results show that selection pressures imposed by pathogens induce individual behavioral modifications, leading to altered mate choice and could reduce promiscuity in a wild nonhuman primate population.

Right on track? Performance of satellite telemetry in terrestrial wildlife research.

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.

The Influence of Social Systems on Patterns of Mitochondrial DNA Variation in Baboons.

Behavior is influenced by genes but can also shape the genetic structure of natural populations. Investigating this link is of great importance because behavioral processes can alter the genetic diversity on which selection acts. Gene flow is one of the main determinants of the genetic structure of a population and dispersal is the behavior that mediates gene flow. Baboons (genus Papio) are among the most intensely studied primate species and serve as a model system to investigate the evolution of social systems using a comparative approach. The general mammalian pattern of male dispersal and female philopatry has thus far been found in baboons, with the exception of hamadryas baboons (Papio hamadryas). As yet, the lack of data on Guinea baboons (Papio papio) creates a taxonomic gap in genus-wide comparative analyses. In our study we investigated the sex-biased dispersal pattern of Guinea baboons in comparison to hamadryas, olive, yellow, and chacma baboons using sequences of the maternally transmitted mitochondrial hypervariable region I. Analyzing whole-range georeferenced samples (N = 777), we found strong evidence for female-biased gene flow in Guinea baboons and confirmed this pattern for hamadryas baboons, as shown by a lack of genetic-geographic structuring. In addition, most genetic variation was found within and not among demes, in sharp contrast to the pattern observed in matrilocal primates including the other baboon taxa. Our results corroborate the notion that the Guinea baboons' social system shares some important features with that of hamadryas baboons, suggesting similar evolutionary forces have acted to distinguish them from all other baboons.

Hybridization and speciation.

Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the Dobzhansky-Muller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization.

Introgressive hybridization in southern African baboons shapes patterns of mtDNA variation.

Species, as main evolutionary units have long been considered to be morphological entities with limited hybridization potential. The occurrence of taxa which maintain morphological distinctness despite extensive hybridization is an interesting phenomenon. To understand the evolution of these taxa, descriptions of contemporary morphological and genetic variation are essential, also to reconstruct sound phylogenies. Baboons, with their wide geographic range, variant morphotypes, and extensive hybridization offer an intriguing model for those studies. We focus on the complex situation in southern Africa that, in contrast to east Africa, has been neglected in terms of baboon hybridization history. We aim to clarify the distribution and identify possible overlapping zones between different, previously described mitochondrial (mt) DNA clades of baboons that do not match with the ranges of traditionally recognized species. On the basis of the widespread sampling and mitochondrial cytochrome b gene sequencing, we constructed a phylogenetic tree that separates representatives of the two southern African baboon species, yellow and chacma baboons, into six clades: southern, northern and eastern chacmas, Kinda baboons and southern and Luangwa yellow baboons. The ranges of the chacma clades come into close contact or overlap in two regions in the Republic of South Africa and Namibia. Our phylogenetic reconstruction reveals mitochondrial paraphyly for chacma and yellow baboons, which is probably caused by introgressive hybridization and subsequent nuclear swamping, whereby males of the chacma morphotype population from the south invaded the yellow morphotype population in the north bringing their morphotype into a population that maintained its yellow baboon mtDNA.

Verreaux's eagles (Aquila verreauxi) as potential predators of hamadryas baboons (Papio hamadryas hamadryas) in Eritrea.

In this paper we describe for the first time encounters of Verreaux's eagle (Aquila verreauxi) with hamadryas baboons (Papio hamadryas hamadryas) in the central highlands of Eritrea (15 degrees 22' N, 38 degrees 58' E, 2300 m). During 12 h of observation on 4 days, we observed four encounters of Verreaux's eagles with baboons, of which three can be classified as possible attacks. The baboons always responded with alarm calls. In three cases some immatures rushed to adult group members and clung to them, particularly to the adult male. Adult males threatened the eagle, and the whole group did not flee. The response of baboons towards smaller raptors like tawny eagles (Aquila rapax) and black kites (Milvus migrans) was very different. The adult baboons gave no alarm barks but scanned the raptors. The permanent presence of a pair of Verreaux's eagles in the home range of the baboons may represent a considerable predation pressure, at least for immature baboons.

Medicare coverage of outpatient ambulatory intravenous antibiotic therapy: a program that pays for itself.

A number of studies have documented the safety, efficacy, and cost-effectiveness of outpatient intravenous (i.v.) antibiotic therapy for patients with infectious diseases. Nevertheless, Medicare policy prohibiting coverage of outpatient, self-administered drugs has severely limited access of Medicare patients to ambulatory i.v. therapy, thus forcing them to rely on more costly, impatient hospital care. To test the hypothesis that a new Medicare benefit providing coverage for ambulatory i.v. antibiotic therapy could significantly reduce the program's expenditures for the treatment of infectious diseases (including pneumonia, osteomyelitis, cellulitis, and endocarditis), a cost model was constructed with use of patient care information from the clinical literature as well as clinical experts, Medicare data, and other medical claims databases. The model shows cumulative 5-year savings of nearly $1.5 billion associated with the new Medicare benefit. Policy makers should consider implementing such a benefit.

Are methods for estimating QALYs in cost-effectiveness analyses improving?

OBJECTIVES: The objectives of this study were to examine variations in the methods used by researchers to estimate QALYs in published cost-effectiveness analyses, and to investigate whether the methods have improved over time. DATA AND METHODS: Using a MEDLINE search, the authors identified 86 original cost-effectiveness analyses, published between 1975 and 1995, that used QALYs as the measure of effectiveness. For each study, they recorded the health-state classification system, the source of the preference weights, the measurement technique, and the discount rate. The methods used were compared with the recommendations of the U.S. Panel on Cost-Effectiveness in Health and Medicine. RESULTS: Only 20% of the studies used "generic" health-state classification systems (e.g., health utilities index); 21% relied on community-based weights; 40% used formal measurement techniques (e.g., time-tradeoff method); and 88% discounted both future costs and QALYs. There was little evidence that methods had improved over time. CONCLUSIONS: The results illustrate extensive variation in the construction of QALYs in cost-effectiveness analyses and reveal that most studies have not adhered to practices now recommended by leaders in the field. There is a need for more methodologic rigor and consistency if the results of such studies are to be compared and used for purposes of allocating resources.

The FDA and regulation of cost-effectiveness claims.

The Food and Drug Administration (FDA) has issued draft guidelines that would require more rigorous standards for making pharmacoeconomic claims. This paper critiques the guidelines and explores the objectives of market regulation for health-related cost and effectiveness information on pharmaceutical products. It argues that the FDA should proceed with caution and flexibility. In particular, regulations should recognize the potential usefulness of pharmacoeconomic information in helping health care decisionmakers make better-informed choices. They also should acknowledge the enhanced ability of those using the information to evaluate pharmacoeconomic studies and the degree to which the various players in the market can impose their own regulatory discipline.

A new desensitizing dentifrice: preliminary report.

Dentin sensitivity is one of the most painful, ubiquitous, and least satisfactorily treated chronic problems of the teeth. The purpose of this clinical trial was to test the sensitivity-reducing effectiveness of five dentifrices over a six-week period. For the study, 176 adults, ages 18 to 63, exhibiting a total of 486 hypersensitive surfaces, were randomly allocated to five experimental groups to use one of the following: a strontium chloride dentifrice, a 0.4% stannous fluoride gel, a pluronic F-127-sodium citrate gel, a pluronic F-127 gel, or a control dentifrice. No specific instructions were provided as to the frequency or method of toothbrushing; thus, the participants brushed their teeth in their usual manner. The analysis of the data was limited to 168 persons who complied with study procedures. Chi-square analysis examined the statistical differences between the four test agents and the control formulation. The desensitizing effect of the pluronic plus sodium citrate gel was highly significant, and the plain pluronic F-127 preparation was effective to a lesser degree. Patients using the strontium chloride or stannous-fluoride-containing dentifrices did not exhibit a significant improvement over the control group. This study demonstrated that a pluronic polyol gel containing sodium citrate is highly effective in controlling tooth hypersensitivity.

Clinical study of an amine fluoride gel and acidulated phosphate fluoride gel.

This study compared caries inhibition in children by an amine fluoride and an acidulated phosphate fluoride when administered in a topically applied gel. In addition, the effects of applying amine fluoride daily and weekly were compared. Four hundred and sixty-eight children, ages 6 to 13, were randomly assigned to one of five treatment groups and received a total of five, 5-minute treatments. The treatment and interval between each of the five treatments were as follows:(A)acidulated phosphate fluoride daily, (B) amine fluoride daily, (C) amine fluoride weekly, (D) placebo daily, and (E) placebo weekly. When the children were examined for total Decayed, Missing, and Filled Surfaces (DMFS) increments 2 years later, no significant differences were observed. However, when the data were examined for effects of DMFS for specific tooth surface, significant restriction (61%) of occlusal increment was shown in the group which was treated with amine fluoride daily for 5 consecutive days as compared with the control group.

Longitudinal effects of an antibacterial oral rinse on gingivitis and dental plaque.

The purpose of this study was to determine what effect oral rinse containing alexidine dihydrochloride (Calgon Consumer Products Company, a Subsidiary of Merck & Co.) would have on gingivitis and plaque. Following a dental prophylaxis, 167 male and female, 7-12-year-old students in Puerto Rican elementary school rinsed twice daily for 60 sec. with 10 ml of either a placebo oral rinse or one containing alexidine dihydrochloride. All students brushed their teeth daily in school. Gingivitis and plaque were scored on all buccal and lingual tooth surfaces prior to the prophylaxis and on days 30, 90, and 160. On these dates, blood and urine analysis were also made. A second prophylaxis was given at the end of the study. The adjusted mean gingivitis and plaque scores were compared between the treatment and placebo groups at 30, 90, and 160 days using analysis of covariance. The alexidine dihydrochloride oral rinse was found to reduce significantly gingivitis after 160 days (p less than 0.02) of treatment and plaque scores 30 days (p less than 0.01), 90 days (p less than 0.001), and 160 days (p less than 0.001) after treatment. No blood or urine changes were attributed to the active ingredient oral rinse.