Blood corticosterone levels and intersexual selection games: best-of-bad-job strategies of male common lizards

Glucocorticoids affect physiology and behaviour, reproduction and potentially sexual selection as well. Shortterm and moderate glucocorticoid elevations are suggested to be adaptive, and prolonged and high elevations may be extremely harmful. This suggests that optimal reproductive strategies, and thus sexual selection, may be dose dependent. Here, we investigate effects of moderate and high elevations of blood corticosterone levels on intra- and intersexual behaviour and mating success of male common lizards Lacerta vivipara. Females showed less interest and more aggressive behaviour towards high corticosterone males and blood corticosterone levels affected male reproductive strategy. Males of moderate and high corticosterone elevations, compared with Control males, showed increased interest (i.e., higher number of chases, tongue extrusions, and approaches) towards females and high corticosterone males initiated more copulation attempts. However, neither increased male interest nor increased copulation attempts resulted in more copulations. This provides evidence for a best-of-a-bad-job strategy, where males with higher corticosterone levels compensated for reduced female interest and increased aggressive female behaviour directed towards them, by showing higher interest and by conducting more copulation attempts. Blood corticosterone levels affected intrasexual selection as well since moderate corticosterone levels positively affected male dominance, but dominance did not affect mating success. These findings underline the importance of female mate choice and are in line with adaptive compensatory behaviours of males. They further show that glucocorticoid effects on behaviour are dose dependent and that they have important implications for sexual selection and social interactions, and might potentially affect Darwinian fitness

Rheumatoid factors in primary Sjögren's syndrome (pSS) use diverse VH region genes, the majority of which show no evidence of somatic hypermutation

Rheumatoid factor (RF) is the most common autoantibody found in patients with Sjögren's syndrome (SS). To study the genetic origin and the mechanisms acting behind its generation we have characterized and sequenced the immunoglobulin VH genes used by 10 IgM RF MoAbs derived from peripheral blood of six female patients with pSS. We compared the structure of the RF immunoglobulin VH genes with those obtained previously from rheumatoid arthritis (RA) patients and healthy immunized donors (HID). VH1 and VH4 were each used by four RF clones, one clone was encoded by VH3 family gene and one by VH2 family gene. This distribution frequency was different from that observed in RA, where VH3 was the dominant family, followed by VH1. Eight different germ-line (GL) genes encoded the clones and all of these genes were seen previously in RA and/or HID RF. Five clones rearranged to JH6, four rearranged to JH4 and one to JH5, in contrast to RF from RA and HID, where JH4 was most frequently used. D segment use and CDR3 structure were diverse. Interestingly, three out of four VH4 clones used the GL gene DP-79 that was seen frequently in RA RF. The degree of somatic mutation in the pSS RF was very much lower than seen in RA and HID RF. All the pSS RF clones except three were in or very close to GL configuration. This indicates that there is little role for somatic hypermutation and a germinal centre reaction in the generation of RF from peripheral blood in pSS

The incidence of rhegmatogenous retinal detachment in the Netherlands: Dutch Rhegmatogenous Retinal Detachment Study Group

Objective: To estimate the incidence and characteristics of rhegmatogenous retinal detachment (RRD) in The Netherlands in 2009. Design: Retrospective, observational case series. Participants: All patients with RRD in the Dutch population in 2009. Methods: By reviewing surgical logs, cases of primary RRD repair in 2009 were identified. Exclusion criteria included RRD before 2009 and exudative, tractional, or traumatic retinal detachments. Patient demographics, date of surgery, and lens status were documented. Incidence of RRD and 95% confidence intervals (CIs) were calculated based on the Poisson distribution. Age distribution, male-to-female ratio, and proportion of RRD patients with prior cataract extraction (CE) were determined. A Student t test was used to examine differences in the incidence of RRD between groups. Main Outcome Measures: Annual RRD incidence in the population and per gender-adjusted age category and proportion of RRD patients with prior CE. Results: The annual RRD incidence was 18.2 per 100 000 people (95% CI, 11.4–18.8), with a peak incidence of 52.5 per 100 000 people (95% CI, 29.4–56.8) between 55 and 59 years of age. The Bilateral RRD rate was 1.67%. Macula-off presentation occurred in 54.5% of all RRD patients. Prior CE was noted in 33.5% of RRD eyes. The male-to-female ratio was 1.3:1, and RRD incidence was statistically significantly more frequent in males (P 0.0001). Conclusions: Rhegmatogenous retinal detachment is predominantly a disease of the population older than 50 years, and males are more susceptible to RRD. The annual RRD incidence is highly dependent on demographic characteristics