Do Early-Life Conditions Drive Variation in Senescence of Female Bighorn Sheep?

The rate of senescence may vary among individuals of a species according to individual life histories and environmental conditions. According to the principle of allocation, changes in mortality driven by environmental conditions influence how organisms allocate resources among costly functions. In several vertebrates, environmental conditions during early life impose trade-offs in allocation between early reproduction and maintenance. The effects of conditions experienced during early life on senescence, however, remain poorly documented in wild populations. We examined how several early-life environmental conditions affected reproductive and survival senescence in wild bighorn sheep. We found long-term effects of high population density at birth, precipitations during the winter before birth, and temperature during the winter following birth that decreased survival after 7 years of age. High temperature during the first summer and autumn of life and high Pacific decadal oscillation decreased reproductive success at old ages. However, harsh early-life environment did not influence the rate of senescence in either survival or reproduction. Contrary to our expectation, we found no trade-off between reproductive allocation prior to senescence and senescence. Our results do show that early-life environmental conditions are important drivers of later survival and reproductive success and contribute to intra-specific variation in late-life fitness, but not aging patterns. These conditions should therefore be considered when studying the mechanisms of senescence and the determinants of variation in both survival and reproductive senescence at older ages.

Flexibility Is Costly: Hidden Physiological Damage From Seasonal Phenotypic Transitions in Heterothermic Species

Heterothermy allows organisms to cope with fluctuating environmental conditions. The use of regulated hypometabolism allows seasonal heterothermic species to cope with annual resource shortages and thus to maximize survival during the unfavorable season. This comes with deep physiological remodeling at each seasonal transition to allow the organism to adjust to the changing environment. In the wild, this adaptation is highly beneficial and largely overcomes potential costs. However, researchers recently proposed that it might also generate both ecological and physiological costs for the organism. Here, we propose new perspectives to be considered when analyzing adaptation to seasonality, in particular considering these costs. We propose a list of putative costs, including DNA damage, inflammatory response to fat load, brain and cognitive defects, digestive malfunction and immunodeficiency, that should receive more attention in future research on physiological seasonality. These costs may only be marginal at each transition event but accumulate over time and therefore emerge with age. In this context, studies in captivity, where we have access to aging individuals with limited extrinsic mortality (e.g., predation), could be highly valuable to experimentally assess the costs of physiological flexibility. Finally, we offer new perspectives, which should be included in demographic models, on how the adaptive value of physiological flexibility could be altered in the future in the context of global warming.

Female reproduction bears no survival cost in captivity for gray mouse lemurs

The survival cost of reproduction has been revealed in many free-ranging vertebrates. However, recent studies on captive populations failed to detect this cost. Theoretically, this lack of survival/reproduction trade-off is expected when resources are not limiting, but these studies may have failed to detect the cost, as they may not have fully accounted for potential confounding effects, in particular interindividual heterogeneity. Here, we investigated the effects of current and past reproductive effort on later survival in captive females of a small primate, the gray mouse lemur. Survival analyses showed no cost of reproduction in females; and the pattern was even in the opposite direction: the higher the reproductive effort, the higher the chances of survival until the next reproductive event. These conclusions hold even while accounting for interindividual heterogeneity. In agreement with aforementioned studies on captive vertebrates, these results remind us that reproduction is expected to be traded against body maintenance and the survival prospect only when resources are so limiting that they induce an allocation trade-off. Thus, the cost of reproduction has a major extrinsic component driven by environmental conditions.

Long-term prevalence data reveals spillover dynamics in a multi-host (Artemia), multi-parasite (Microsporidia) community

In the study of multi-host parasites, it is often found that host species contribute asymmetrically to parasite transmission. Yet in natural populations, identifying which hosts contribute to parasite transmission and maintenance is a recurring challenge. Here, we approach this issue by taking advantage of natural variation in the composition of a host community. We studied the brine shrimps Artemia franciscana and Artemia parthenogenetica and their microsporidian parasites Anostracospora rigaudi and Enterocytospora artemiae. Previous laboratory experiments had shown that each host can transmit both parasites, but could not predict their actual contributions to the parasites' maintenance in the field. To resolve this, we gathered long-term prevalence data from a metacommunity of these species. Metacommunity patches could contain either or both of the Artemia host species, so that the presence of the hosts could be linked directly to the persistence of the parasites. First, we show that the microsporidian A. rigaudi is a spillover parasite: it was unable to persist in the absence of its maintenance host A. parthenogenetica. This result was particularly striking, as A. rigaudi displayed both high prevalence (in the field) and high infectivity (when tested in the laboratory) in both hosts. Moreover, the seasonal presence of A. parthenogenetica imposed seasonality on the rate of spillover, causing cyclical pseudo-endemics in the spillover host A. franciscana. Second, while our prevalence data was sufficient to identify E. artemiae as either a spillover or a facultative multi-host parasite, we could not distinguish between the two possibilities. This study supports the importance of studying the community context of multi-host parasites, and demonstrates that in appropriate multi-host systems, sampling across a range of conditions and host communities can lead to clear conclusions about the drivers of parasite persistence.

Offspring mass variation in tree swallows: A case of bet‐hedging?

The evolution of reproductive strategies is affected by the ability of organisms to deal with future environmental conditions. When environments are temporally unpredictable, however, it is difficult to anticipate optimal offspring phenotype. Diversification of offspring phenotypes, a strategy called diversified bet‐hedging, may allow parents to maximize their fitness by reducing between‐year variation in reproductive success. The link between diversification of offspring phenotypes and individual reproductive success, however, has rarely been documented empirically. We used an eight‐year dataset (1215 broods, 870 females) on individually marked tree swallows (Tachycineta bicolor) to assess whether intra‐brood mass variation was compatible with a diversified bet‐hedging strategy. Intra‐brood mass variation was weakly, but significantly repeatable within females, suggesting consistent individual differences. Greater intra‐brood mass variation, however, was not associated with reduced between‐year variation in reproductive success or increased female reproductive success. Moreover, contrary to diversified bet‐hedging expectations, fledging success of large broods was greater when hatchlings had similar rather than variable masses. Our results suggest that intra‐brood mass variation may not result from diversified bet‐hedging, but rather from complex interactions between environmental, brood, and maternal characteristics.

State transitions: a major mortality risk for seasonal species

Ageing results from the accumulation of multifactorial damage over time. However, the temporal distribution of this damage remains unknown. In seasonal species, transitions between seasons are critical periods of massive physiological remodelling. We hypothesised that these recurrent peaks of physiological remodelling are costly in terms of survival. We tested whether captive small primates exposed to an experimentally increased frequency of seasonal transitions die sooner than individuals living under natural seasonality. The results show that experiencing one additional season per year increases the mortality hazard by a factor of 3 to 4, whereas the expected number of seasons lived is only slightly impacted by the seasonal rhythm. These results demonstrate that physiological transitions between periods of high and low metabolic activity represent a major mortality risk for seasonal organisms, which has been ignored until now.

Snapshot assessment of RNA-expression in severely burned patients using the PAXgene™ Blood RNA System: A pilot study

Severe burn induces destabilization of the immune system and the likelihood of multiple organ dysfunction syndrome. Current studies focus on RNA-expression analyses of immune system cells, however, the present methods of analysis are complex, potentially altered by artefacts and therefore not feasible for routine analyses. The new PAXgene Blood RNA System provides "snapshot" analysis of RNA by immediate cell lysis and prevention of RNA-degradation. Using this system the aim of this study was to analyse intracellular cytokine RNA-expression under clinical conditions. Whole blood samples (PAXgene tubes) of nine severely burned patients were drawn at admission and 6, 12, 24, 48 and 72h after trauma during routine treatment. Four healthy individuals served as control. Analysis of RNA-expression of TNF-alpha as pro-inflammatory and IL-10 as anti-inflammatory mediator was performed by RT-PCR. The RNA-expression of TNF-alpha was increased at 72h after burn. The increase occurred mainly in surviving patients. In contrast, RNA-expression of IL-10 was elevated already at 24h and the difference between surviving and deceased patients occurred earlier. We demonstrate for the first time a "snapshot" analysis of cytokine RNA-expression in severely burned patients under routine conditions. The results correspond well to current hypothesis of posttraumatic MODS development.

Quantitative Assessment of Angiogenesis in Murine Antigen-Induced Arthritis by Intravital Fluorescence Microscopy

Inhibition of angiogenesis might be a therapeutic approach to prevent joint destruction caused by the overgrowing synovial tissue during chronic joint inflammation. The aim of this study was to investigate angiogenesis in the knee joint of mice with antigen-induced arthritis (AIA) by means of intravital microscopy. In 14 mice (C57BL6/129Sv) intravital microscopic assessment was performed on day 8 after AIA induction in two groups (controls, AIA). Synovial tissue was investigated by intravital fluorescence microscopy using FITC-dextran (150 kD). Quantitative assessment of vessel density was performed according to the following categories: functional capillary density (FCD, vessels <10 microm in diameter), functional vessel density (FVD, vessels >10 microm) and FVD of vessels with angiogenic criteria (convoluted vessels, abrupt changes of diameter, vessels which are generated by sprouting and progressively pruned and remodelled). Microvessel count was performed using immunohistochemistry. There was no significant difference in FCD between the control group (337 +/- 9 cm/cm2; mean +/- SEM) and the AIA group (359 +/- 13 cm/cm2). The density of vessels larger than 10 microm diameter was significantly increased in animals with AIA (135 +/- 10 vs. 61 +/- 5 cm/cm2 in control). The density of blood vessels with angiogenic criteria was enhanced in arthritic animals (79 +/- 17 vs. 12 +/- 2 cm/cm2 in control). There was a significant increase in the microvessel count in arthritic animals (297 +/- 25 vs. 133 +/- 16 mm(-2) in control). These findings demonstrate that angiogenesis in murine AIA can be assessed quantitatively using intravital microscopy. Further studies will address antiangiogenic strategies in AIA.

Ileoileal intussusception caused by a Ewing sarcoma tumour. An unusual case report

Intussusception typically occurs in childhood, presenting with a well-known medical history and clinical symptoms. Pathologically, a "leading point" may be attributed to lymphadenomatosis, polyps, or a tumour. In older patients and adolescents, the diagnosis can be complicated due to the lower incidence and variable subacute symptoms. We report on an 18-year-old patient with increasing abdominal discomfort over several weeks. External diagnostics showed no pathological signs or were misinterpreted as a malfunction of intestinal motility. The patient experienced increasing colics, recurrent vomiting, dehydration and weight loss. Finally he was transferred to our paediatric surgical department and laparotomy had to be performed for the clinical and radiological signs of an ileus. An ileoilealic intussusception was found, caused by a small bowel tumour, which almost completely obstructed the intestinal lumen. It was resected and bowel continuity was re-established. Histopathology revealed a very rare, highly malignant mesenchymal Ewing sarcoma, infiltrating the complete bowel wall. After the postoperative course, the patient was transferred to our oncological department for chemotherapy. In older children or young adults, intestinal malignancies are extremely rare. Nevertheless, if these patients suffer from unspecific complaints of chronic intestinal obstruction, a tumour must be ruled out. A Ewing sarcoma may be responsible for an intussusception.

[The femoral neck fracture in the elderly patient - cemented or cementless hip arthroplasty?]

This is a report on the treatment results of femoral neck fractures with a cemented (group 1) and cementless (group 2) type of hip prosthesis, resp. 72 patients were enrolled. 35 patients were treated with a cemented hip prosthesis (mean age: 78 years), and 37 patients with a cementless modular hip prosthesis (mean age: 77 years). In the cemented group we observed 5 cases of hypotension during insertion of the prosthesis in the femoral shaft. One of these patients required mechanical resuscitation during surgery. In the second group 3 cases of proximal femur fissure and one case of distal femoral fracture were recorded. One year after surgery 43 patients presented for follow up evaluation (cemented group: n = 24; cementless group: n = 19). Both groups revealed comparable results according to the Harris Hip Score (75 versus 78,3 points). No prosthesis loosening was observed in either group. In our view the cemented hip prosthesis is the treatment of choice for femoral neck fractures among the old and very old, if no stabile osteosynthesis can be performed. Patients with cardiopulmonary risk factors, however, may profit from cementless hip arthroplasty to avoid the well known cardiodepression during surgery.

Exacerbation of antigen-induced arthritis in inducible nitric oxide synthase-deficient mice

OBJECTIVE

Inhibition of nitric oxide (NO) produced by inducible NO synthase (iNOS) is suggested to be beneficial in experimental arthritis. Although NO is important for the integrity of the microcirculation, the effects of inhibition of iNOS on the synovial microcirculation are not currently known. This study investigated the synovial microcirculation and leukocyte-endothelial cell interactions in iNOS-deficient mice with antigen-induced arthritis (AIA) and compared these findings with disease severity.

METHODS

Fourteen homozygous iNOS-/- and 14 iNOS+/+ mice were used. The severity of AIA was assessed by measuring knee joint swelling and by histologic scoring. The number of rolling and adherent leukocytes was quantitatively analyzed in synovial microvessels using intravital microscopy of intraarticular synovial tissue. Nitrite/nitrate concentrations were measured, and the expression of iNOS, E- and P-selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 (VCAM-1) was assessed by immunohistochemistry.

RESULTS

In iNOS+/+ animals with AIA, the plasma concentration of nitrite/nitrate was increased 3-fold and iNOS expression was detected in cells of the joint. Swelling of the knee joint as well as leukocyte infiltration were enhanced in the iNOS-/- arthritic animals compared with iNOS+/+ mice with AIA. AIA-associated leukocyte-endothelial cell interaction in synovial postcapillary venules was more pronounced in iNOS-/-, compared with iNOS+/+, arthritic mice. A strong expression of P-selectin and VCAM-1 was observed in the iNOS-/- arthritic mice only.

CONCLUSION

These data suggest that NO production by iNOS in vivo has antiinflammatory effects in experimental arthritis, by mediating a reduction in leukocyte adhesion and infiltration.

[Treatment of per- and subtrochanteric femoral fractures by gamma nails and modular hip prostheses. Differential indications and results]

From January 1997 to August 1998 all stable and nonstable trochanteric femoral fractures (n = 72) were treated routinely by gamma nail using the correct operative technique. Patients showing additional osteoarthritis of the hip in radiographs hip replacement was performed by a cementless modular femoral hip prostheses from January 1996 to August 1998 (n = 28). Follow up period was 6 to 18 months. Operation time and blood loss were higher using the prostheses. However complications and lethality (< 5%) were not different during postoperative course. In each group three operative technical complications occurred. Using a modified Harris Hip Score (without range of motion, contractions) the score was decreased non significant comparing both groups first of all in unstable fractures until follow up. In each group one revision (loosening of prostheses, excessive shortening of femoral neck) was necessary. Using the correct operative technique, the gamma nail proved to be a save device with good outcome. Outcome using modular prostheses is comparable to gamma nail. Therefore the use of modular prostheses is justified in case of osteoarthrosis and in some cases of very unstable fracture.

["Bell clappers" with "ophthalmologic alarm". Apropos of 2 cases of colloid cysts of the 3d ventricle]

We report two cases of third ventricle colloid cyst in atypical adult's neurological descriptions, tracked down by ophthalmologist, proved by computed tomography and magnetic resonance imaging. We describe physio-pathological mechanism and dwell on different ophthalmological events of exceptional occurrence with those benign tumours and on ophthalmological investigation's importance in case of persisting and unexplained headache. We conclude with spontaneous clinical course, and neurological surgery's efficacy on hydrocephalus.

[Cornea and anterior chamber implant with flexible closed haptics]

Authors report the result of 148 cases of flexible (with closed haptics) anterior chamber lens implantation. Analysis of per and post-operative corneal complications, Study shows increase in time of such complications, in relation to secondary displacement and alteration of lens shape.

[A case of leiomyoma of the iris]

A case of leiomyoma of the iris confirned to the nasal quadrant in a 64 year old man is presented. The clinical and histopathological characteristics of this observation confirms the classical data about this rare tumor : clinical silence, discovery through a complication, difficult diagnosis, therapeutical value of the surgical biopsy and good prognosis.