Disruptive viability selection on a black plumage trait associated with dominance.

Traits used in communication, such as colour signals, are expected to have positive consequences for reproductive success, but their associations with survival are little understood. Previous studies have mainly investigated linear relationships between signals and survival, but both hump-shaped and U-shaped relationships can also be predicted, depending on the main costs involved in trait expression. Furthermore, few studies have taken the plasticity of signals into account in viability selection analyses. The relationship between signal expression and survival is of particular interest in melanin-based traits, because their main costs are still debated. Here, we first determined the main factors explaining variability in a melanin-based trait linked to dominance: the bib size of a colonial bird, the sociable weaver Philetairus socius. We then used these analyses to obtain a measure representative of the individual mean expression of bib size. Finally, we used capture-recapture models to study how survival varied in relation to bib size. Variation in bib size was strongly affected by year and moderately affected by age, body condition and colony size. In addition, individuals bearing small and large bibs had higher survival than those with intermediate bibs, and this U-shaped relationship between survival and bib size appeared to be more pronounced in some years than others. These results constitute a rare example of disruptive viability selection, and point towards the potential importance of social costs incurred by the dominance signalling function of badges of status.

After wounding, a G-protein coupled receptor promotes the restoration of tension in epithelial cells.

The maintenance of epithelial barrier function involves cellular tension, with cells pulling on their neighbors to maintain epithelial integrity. Wounding interrupts cellular tension, which may serve as an early signal to initiate epithelial repair. To characterize how wounds alter cellular tension, we used a laser-recoil assay to map cortical tension around wounds in the epithelial monolayer of the Drosophila pupal notum. Within a minute of wounding, there was widespread loss of cortical tension along both radial and tangential directions. This tension loss was similar to levels observed with Rok inactivation. Tension was subsequently restored around the wound, first in distal cells and then in proximal cells, reaching the wound margin about 10 minutes after wounding. Restoring tension required the GPCR Mthl10 and the IP3 receptor, indicating the importance of this calcium signaling pathway known to be activated by cellular damage. Tension restoration correlated with an inward-moving contractile wave that has been previously reported; however, the contractile wave itself was not affected by Mthl10 knockdown. These results indicate that cells may transiently increase tension and contract in the absence of Mthl10 signaling, but that pathway is critical for fully resetting baseline epithelial tension after it is disrupted by wounding.

After wounding, a G-protein coupled receptor promotes the restoration of tension in epithelial cells.

The maintenance of epithelial barrier function involves cellular tension, with cells pulling on their neighbors to maintain epithelial integrity. Wounding interrupts cellular tension, which may serve as an early signal to initiate epithelial repair. To characterize how wounds alter cellular tension we used a laser-recoil assay to map cortical tension around wounds in the epithelial monolayer of the Drosophila pupal notum. Within a minute of wounding, there was widespread loss of cortical tension along both radial and tangential directions. This tension loss was similar to levels observed with Rok inactivation. Tension was subsequently restored around the wound, first in distal cells and then in proximal cells, reaching the wound margin ∼10 min after wounding. Restoring tension required the GPCR Mthl10 and the IP3 receptor, indicating the importance of this calcium signaling pathway known to be activated by cellular damage. Tension restoration correlated with an inward-moving contractile wave that has been previously reported; however, the contractile wave itself was not affected by Mthl10 knockdown. These results indicate that cells may transiently increase tension and contract in the absence of Mthl10 signaling, but that pathway is critical for fully resetting baseline epithelial tension after it is disrupted by wounding.

A simple sexing test for elephant species and its application to faecal DNA.

We developed a novel real-time PCR assay for rapid sexing in all three elephant species, which amplifies small fragments of the orthologous sexual chromosome zinc finger protein genes ZFX/ZFY (65 bp). This assay is a simple, inexpensive and reliable tool that is suitable for non-invasive DNA samples and can be incorporated into larger SNP panels for individual identification and population genetic studies.

Non-invasive measurement of cardiac output during atrial fibrillation: comparison between cardiac magnetic resonance imaging and inert gas rebreathing.

OBJECTIVES: Atrial fibrillation (AF) is one of the most frequent heart rhythm disorders. It potentially influences cardiac function and its measurement. Cardiac magnetic resonance imaging (CMR) has become the new gold standard for non-invasive assessment of cardiac output (CO). A novel inert gas rebreathing (IGR) device based on the Fick Principle also proved promising in patients in sinus rhythm (SR). The aim of our study was to compare the agreement of non-invasive CO measurements between CMR and IGR in AF patients. METHODS: A total of 68 patients, 34 with AF and 34 pair-matched controls in SR, were included. RESULTS: Bland-Altman analysis showed good agreement between both methods, with an average deviation of 0.2 +/-1.2 l/min in the AF group versus 0.3 +/-1.0 l/min in the SR group (p = 0.77). IGR demonstrated good agreement for CO between 2.0 and 5.4 l/min. However, in hyperdynamic circulatory conditions (CO >5.5 l/min), the increasing disagreement of IGR and CMR measurements reached statistical significance. CONCLUSIONS: Non-invasive CO measurements using CMR and IGR are feasible in patients suffering from AF. Good agreement was found between the two methods in an unselected cohort. Hyperdynamic circulatory conditions can lead to significant measurement differences which, however, do not affect the reproducibility of IGR.

IL-6 determination in serum of kidney graft recipients by a new bedside test: its diagnostic relevance.

Interleukin-6 (IL-6) has diagnostic importance as one of the earliest indicators of inflammation, tissue damage, hypoxia, or infection. In contrast to the time-consuming immunoassays actually used in many laboratories, results of a new IL-6 bedside test, which is interpreted visually or photometrically, are available at 20 minutes. The photometric measurement using a stored standard curve allowed differentiation of five ranges: <50, 50-100, >100-200, >200-500, and >500-1000 pg/mL. The aim of our study was to evaluate the diagnostic relevance of this new IL-6 bedside test in four well-defined, noninfectious and infectious events after kidney transplantation. In a retrospective study the IL-6 serum levels were measured in a total of 269 serum samples from 27 renal graft recipients. Analysis of all data clearly showed that the majority of elevated IL-6 levels occurred in connection with bacterial infections. Viral infections did not result in an increase of IL-6 >50 pg/mL. Thus, from a clinical point of view this new bedside test can be recommended.

Association between students' personality traits and hand hygiene compliance during objective standardized clinical examinations.

BACKGROUND: Although the need for hand hygiene (HH) is generally accepted, studies continue to document inadequate compliance. Medical students are taught about the importance of HH to prevent nosocomial infections, and receive training in the correct procedures for HH. However, personality traits (social orientation and achievement orientation) may influence HH compliance. People with high social orientation feel socially responsible and act cooperatively, and people with high achievement orientation are ambitious and competitive. AIM: To evaluate the relationship between HH compliance and personality traits of medical students. METHODS: The HH compliance of 155 students was observed during objective standardized clinical examinations (OSCEs). Social orientation and achievement orientation were measured using the corresponding scales of the Freiburg Personality Inventory - Revised. FINDINGS: Social orientation did not differ between students with high HH compliance and students with low HH compliance [F(1) = 3.87, P = 0.052, η(2) = 0.045]. For achievement orientation, a moderate effect was found between low and high HH compliance [F(1) = 11.242, P = 0.001, η(2) = 0.119], and students with high HH compliance were found to be more achievement orientated than students with low HH compliance. CONCLUSION: Achievement orientation plays a major role during OSCEs, while social orientation is less emphasized. To the authors' knowledge, this is the first study to show that HH compliance is associated with achievement orientation in achievement situations.

Reduced immunogenicity of long-term, passively enhanced rat renal allografts and passive transfer of graft protection.

Enhancing alloantiserum was produced by immunizing male BD IX inbred rats with density gradient separated nylon-wool adherent spleen lymphocytes from male rats of the major histocompatibility complex (MHC) different inbred strain Sprague-Dawley (SD). Long-term surviving (BD IX X SD) F1 to BD IX kidney grafts were achieved by treating the recipients with 1 ml alloantiserum at the time of transplantation. After greater than 100 days 7 passively enhanced F1 kidneys were retransplanted into naive BD IX rats. Four out of 7 secondary recipients, producing only low levels of lymphocytotoxic antibodies, survived for greater than 100 days, 3/7 rats died of surgical or infection complications. Twenty-one naive BD IX recipients of normal F1 kidneys were treated with serum (1 ml i.v.) and/or spleen lymphocytes (1 X 10(7) i.v.) obtained from the long-term survivors. An indefinite graft survival was achieved in 13 out of 21 rats. After greater than 150 days 6 out of these 13 passively enhanced F1 kidneys were retransplanted into naive BD IX rats which were challenged at the time of grafting with 4 X 10(7) SD lymphocytes to elicit rejection. Six out of 6 kidneys survived greater than 150 days. Thus, the long-term survival of rat kidney allografts in this model is associated with a strong reduction of graft immunogenicity as well as the development of suppressor cells and enhancing antibodies.

Reduced MHC class II antigen expression on rat heart and kidney cells after in vitro exposure to longwave ultraviolet irradiation.

The pretreatment of both kidney and heart donor with the photosensitizer 8-methoxy-psoralen followed by in vitro longwave ultraviolet graft irradiation (PUVA therapy) significantly prolonged graft survival times in rats even across a strong major histocompatibility complex (MHC) barrier. Immunohistological studies using monoclonal antibodies (Mab) to rat MHC class I and II antigens showed a significant reduction of class II antigen expression after PUVA therapy in both Sprague-Dawley rat kidneys and hearts. Using MHC class I Mab there were no differences in distribution pattern in untreated as well as in PUVA treated organs. Thus, our results represent the first in vivo evidence that photochemotherapy-induced graft survival time prolongation is closely connected with its ability to reduce MHC class II antigen expression.

Dynamics of donor-reactive IgG, IgA and IgM antibodies against T and B lymphocytes early after clinical kidney transplantation using flow cytometry.

Using flow cytometry, 32 kidney graft recipients were monitored retrospectively for at least 1 month to study the dynamics of serum IgG, IgA and IgM antibodies against donor T and B lymphocytes before and after transplantation. Donor spleen lymphocytes were used as targets. In the B cell cross-match, the surface immunoglobulins were blocked with an anti-human immunoglobulin antibody. A high frequency of donor-reactive antibodies was detected early after transplantation, especially when the sera were tested against B lymphocytes. Surprisingly, donor-reactive antibodies of the IgA isotype made up a substantial proportion of all antibodies detected. Within the first month after transplantation, six out of 32 patients (19%) developed IgG antibodies against donor T lymphocytes and nine out of 35 patients (28%) formed IgG antibodies against B lymphocytes. A similar situation was found for IgA antibodies: 22% of the recipients were positive for IgA antibodies against donor T lymphocytes and 34% against B lymphocytes after transplantation. Lower antibody frequencies were found for IgM antibodies (16% and 19%, respectively). From our data we conclude that for at least some of the parameters studied their individual dynamics reflect the complex immunological mechanisms occurring early after transplantation.

Massive elevation of procalcitonin plasma levels in the absence of infection in kidney transplant patients treated with pan-T-cell antibodies.

OBJECTIVE: To determine the value of procalcitonin (PCT) monitoring in transplant patients receiving pan-T-cell antibody therapy. DESIGN: Retrospective clinical study. SETTING: A collaborative study between the Institute of Medical Immunology, the Department of Nephrology and Internal Intensive Care, both Charite, Humboldt University Berlin, and the Department of Laboratory Medicine, Friedrichshain Hospital, Berlin, Germany. PATIENTS AND INTERVENTIONS: Thirty-one patients were included in the study: 8 kidney transplant patients with acute rejection episodes, 5 receiving OKT3 monoclonal antibody therapy, 3 receiving steroid bolus therapy; 21 patients undergoing renal transplantation, 11 receiving ATG perioperatively, 10 without ATG administration; 2 patients undergoing renal transplantation and receiving anti-IL-2R mAb. MEASUREMENTS AND RESULTS: Procalcitonin (PCT) and tumor necrosis factor (TNF) alpha plasma levels were measured in infection-free transplant patients treated with the pan-T-cell antibodies ATG or OKT3. We found PCT plasma concentrations up to 600 ng/ml (reference < 0.5 ng/ ml), which are comparable to those seen in severe sepsis. Increases in TNF-alpha plasma levels preceded the rises in PCT. After peaking on day 1 of therapy the PCT plasma concentrations returned to normal values independently of further antibody administration. In contrast, steroid bolus therapy or anti-interleukin 2 receptor mAb administration did not increase plasma PCT or TNF-alpha levels. CONCLUSIONS: PCT monitoring for evaluating infectious complications in kidney transplant patients must be very careful during pan-T-cell antibody therapy.

Morphological and enzyme-histochemical changes of the mouse thymus after hydrocortisone.

This study was designed to determine the effect of hydrocortisone on morphology and enzyme-histochemistry of the thymus, on the peripheral blood cell picture, and on skin graft survival time in mice. In addition to the prolongation of survival of skin grafts, to a dose-dependent lymphopenia, and to an increase in the number of circulating neutrophil granulocytes, we found morphologically enlarged epithelial reticular cells with large cytoplasmic vacuoles, which often formed cyst-like structures. Because of their broad enzyme activity it may well be that these epithelial cell derived cysts regulate by means of humoral factor(s) the repopulation of the thymic cortex. In addition semithin sections clearly showed that the polymorphonuclear-like cells in the thymic cortex are altered lymphocytes with fragmented nuclei.

Microvascular surgery in experimental and clinical kidney transplantation.

An improved microsurgical technique for orthotopic rat kidney transplantation is described in detail. (1) End-to-end anastomosis of renal arteries with 7-8 interrupted 10-0 sutures. (2) End-to-end anastomosis of renal veins with 2 continuous semicircular 10-0 sutures. (3) Non-splinted end-to-end ureteric anastomosis with 4 interrupted full-thickness 11-0 sutures. (4) Simultaneous bilateral nephrectomy. Seventy transplantations were analysed. No failure due to complications of the vascular anastomoses occurred. The ureteric anastomoses were complicated by stenosis in only 5 animals (7%). The operation times for vascular anastomoses were 20 (15-24) minutes and for complete transplantation 50 (45-60) minutes. This technique seems to be less time consuming than other methods. Our method has produced a success rate of 93% with well standardized and reproducible organ quality. Preliminary clinical experiences with extracorporeal microvascular reconstruction in 4 cases of injured small polar kidney allograft arteries support the continued application in appropriate situations to increase the number of suitable donor kidneys.