Evidence for contrasting roles for prolactin in eusocial naked mole-rats, Heterocephalus glaber and Damaraland mole-rats, Fukomys damarensis.

Elevated prolactin (PRL) has been associated with the expression of social and cooperative behaviours in a number of vertebrate species, as well as suppression of reproduction. As social mole-rats exhibit both of these traits, PRL is a prime candidate in mediating their social phenotype. While naked and Damaraland mole-rats (NMRs and DMRs) have evolved eusociality independently within their family, both species exhibit an extreme skew in lifetime reproductive success, with breeding restricted to a single female and one or two males. Non-breeding NMRs of both sexes are physiologically inhibited from reproducing, while in DMRs only the non-breeding females are physiologically suppressed. Newly emerging work has implicated the dopamine system and PRL as a component in socially induced reproductive suppression and eusociality in NMR, but the DMR remains unstudied in this context. To investigate evolutionary convergence in the role of PRL in shaping African mole-rat eusociality, we determined plasma PRL concentrations in breeders and non-breeders of both sexes, comparing DMRs with NMRs. Among samples from non-breeding NMRs 80% had detectable plasma PRL concentrations. As a benchmark, these often (37%) exceeding those considered clinically hyperprolactinaemic (25 ng ml-1) in humans: mean ± s.e.m.: 34.81 ± 5.87 ngml-1; range 0.00-330.30 ng ml-1 Conversely, 85% of non-breeding DMR samples had undetectable values and none had concentrations above 25 ng ml-1: 0.71 ± 0.38 ng ml-1; 0.00-23.87 ngml-1 Breeders in both species had the expected variance in plasma PRL concentrations as part of normal reproductive function, with lactating queens having significantly higher values. These results suggest that while elevated PRL in non-breeders is implicated in NMR eusociality, this may not be the case in DMRs, and suggests a lack of evolutionary convergence in the proximate control of the social phenotype in these mole-rats.

Increased expression of transthyretin in leptin-deficient ob/ob mice is not causative for their major phenotypic abnormalities.

The hormone leptin is a critical regulator of adipogenesis and energy metabolism. Similarly, leptin-deficient ob/ob mice display various metabolic abnormalities, including not only obesity and insulin resistance, but also hypogonadism and high bone mass. By genome-wide expression analysis using hypothalamus RNA from wild-type and ob/ob mice, we observed the increased expression of the gene for transthyretin (Ttr) in the latter, as confirmed by quantitative real-time-polymerase chain reaction. Because Ttr encodes a carrier protein for retinol transport, and because we further found increased retinol levels in the serum of ob/ob mice, we investigated whether the additional absence of Ttr would influence the ob/ob phenotype. It was found that Ttr-deficient ob/ob mice were indistinguishable from ob/ob littermates in terms of body weight, as well as serum glucose, insulin and cholesterol levels. Although all of these parameters were identical to wild-type controls in Ttr-deficient mice, we found that the sole deletion of Ttr caused a significant increase of trabecular bone mass, bone marrow adiposity and mean adipocyte area in white adipose tissue. Interestingly, all these latter parameters were highest in Ttr-deficient ob/ob mice, and only in these mice did we observe a full penetrance of liver steatosis at 24 weeks of age. Taken together, our data demonstrate that the increased expression of Ttr in ob/ob mice does not cause (but rather attenuates) their phenotypic abnormalities.

Patient satisfaction after lid loading in facial palsy.

Paralytic lagophthalmos is treated by pretarsal implantation of eyelid weights consisting either of rigid gold weights or flexible platinum chains. Functional results being good, subjective patient satisfaction has been examined only by a small number of studies. The aim of our study, conducted by means of a questionnaire, was to assess subjective patient satisfaction after implantation of different eyelid implants. Questionnaires were sent to 42 patients treated by pretarsal implantation of a gold weight (group 1) and 51 patients with a pretarsally fixed platinum chain (group 2). In total, 46 response sheets were evaluated (16 x gold weight, 30 x platinum chain) and the results were compared. In group 1, 75% of patients were very satisfied to satisfied with the overall result. In group 2, 100% of patients were very satisfied to satisfied with the overall result. In group 1, an infection occurred in 6.5% of patients, an extrusion in 6.5%, and a change of vision in 31%. In group 2, inflammation occurred in 13%, extrusion in 0%, and a change of vision occurred in 13% of patients. On a visual analogous scale from 1 to 10 (1, very good; 10, very poor), group 1 assessed the cosmetic result with an average grade of 3.8 and the functional result with an average grade of 3.1. Group 2 assessed the cosmetic result with the grade 2.9 and the functional result with grade 3.0. The implantation of an eyelid weight for treatment of paralytic lagophthalmos was assessed as positive by a majority of patients. When compared with conventional gold implants, patients who have been treated with a flexible platinum chain are overall more satisfied and have a more favorable subjective view of the cosmetic results.