Improving the success of reinforcement programs: effects of a two-week confinement in a field enclosure on the anti-predator behaviour of captive-bred European hamsters.

Captive breeding programs are an important pillar in biodiversity conservation, aiming to prevent the extinction of threatened species. However, the establishment of self-sustaining populations in the wild through the release of captive-bred animals is often hampered by a high mortality upon release. In this study, we investigated how a 2-week confinement period within a large field enclosure affected the anti-predator behaviour of 'naive' captive-bred hamsters and how potential modifications persisted over time. During three consecutive tests, hamsters were confronted with a moving predator model (a red fox mount, Vulpes vulpes) and their behaviour was filmed. After the initial round of confrontation with the predator model, one group of hamsters (field group) was released into a field enclosure protected from predators, while the other group (control) remained in their individual laboratory cages. After 2 weeks, hamsters from the field group were recaptured and individuals of both groups underwent a second confrontation test. A total of 1 month after their return from the field enclosure, field hamsters were subjected to a last confrontation test. Video analysis, investigating four behavioural variables, revealed that field hamsters significantly modified their behavioural response following the 2 weeks confinement in the enclosure, while this was not the case for control hamsters. In addition, most behavioural modifications in field hamsters persisted over 1 month, while others started to revert. We suggest that an appropriate pre-release period inside a field enclosure will enable naive (captive-bred) hamsters to develop an adequate anti-predator behaviour that will increase their immediate survival probability upon release into the wild. We believe that such measure will be of great importance for hamster conservation programs.

Captive-reared European hamsters follow an offensive strategy during risk-assessment.

Understanding whether captive-reared animals destined to reintroduction are still able to discriminate predators has important implications for conservation biology. The endangered European hamster benefits from conservation programs throughout Europe, in which several thousand individuals are released into the wild every year. Despite this, the anti-predator strategy of hamsters and their ability to maintain predator discrimination in captivity remain to be investigated. Here, we explore the predator discrimination behaviour of captive-reared European hamsters and their response to different predation cues. When first exposed to the urine of cats and goats in a Y-maze test, hamsters spent more time close to the cat scent rather than to the goat scent. In a second experiment, during which hamsters were exposed to a non-mobile European ferret (inside a cage), hamsters significantly increased the time spent close to the ferret's cage and displayed aggressive behaviour towards the ferret. Furthermore, they did not take refuge inside an anti-predation tube (APT), a device designed to upgrade wildlife underpasses and reconnect wild hamster populations. Finally, when exposed to a mobile ferret (but without physical contact), hamsters displayed mobbing and aggressive behaviours towards the ferret, before taking refuge inside the APT. Taken together, our results show that captive-reared hamsters are still able to detect and react to predation cues, but that they initially adopt an offensive strategy (grunting, spitting, mobbing) during the risk-assessment phase. After risk assessment, however, hamsters used the APT as a refuge. Our study provides important insights into the anti-predator behaviour of hamsters. Testing the efficacy of the APT, a device that will allow upgrading wildlife underpasses for the hamster and other rodents, is also of great importance and is instrumental in conservation efforts for these species.

Identification of five new families strengthens the link between childhood choroid plexus carcinoma and germline TP53 mutations.

We present five families of paediatric patients suffering from choroid plexus carcinoma in which we found germline TP53 mutations. Only one of the families conformed to the criteria of Li-Fraumeni syndrome and only three (including the Li-Fraumeni syndrome family) met the Chompret criteria for germline TP53 mutation testing. In the remaining two families no family history of cancer was identified and/or the parents of the patient were shown not to carry the mutation. Our results give further support to the notion that the occurrence of this rare paediatric tumour, especially in combination with a positive family history of cancer, but possibly also without any family history, may be an indicator of a germline TP53 mutation. The identification of this genetic defect has important consequences for cancer prevention and treatment in affected families.

Pediatric adrenal cortical carcinoma: brain metastases and relationship to NF-1, case reports and review of the literature.

Adrenal cortical carcinoma (ACC) is a rare childhood neoplasm that seldom manifests brain metastases; hence few papers in the literature focus on neurological manifestations associated with ACC. Although ACC is known to be a signature tumor type in several inherited cancer predisposition syndromes, particularly Li Fraumeni, ACC has not been previously associated with neurofibromatosis, type 1 (NF-1), an inherited disorder with frequent CNS lesions that might prompt concern for metastatic disease by neuroimaging studies. We present two pediatric patients with ACC and unusual CNS findings. The first child developed metastasis to the brain 4 years after resection of his adrenal primary and 2 and 1 years, respectively, after metastases to the liver and lungs. Soon after our experience with this patient, a girl with known NF-1 presented with virilization; adrenalectomy disclosed an ACC and systemic metastases were found within months. Disseminated disease prompted concern that her complex intracranial lesions identified by neuroimaging studies might represent brain metastases, but this proved to be NF1-related hamartomatous lesions. We review the literature on ACCs in pediatric patients regarding brain metastases and previous associations with NF-1.

Intramedullary spinal cord astrocytomas in children.

BACKGROUND: Intramedullary spinal cord astrocytomas are uncommon tumors in childhood. There is little information on therapy and outcome of astrocytomas in this location. PROCEDURE: A retrospective review was performed for the 10 children who were treated between 1996 and 2003 for spinal cord astrocytomas in our institution. Only one had metastatic disease. All ten patients underwent surgical resection, nine partial and one total. Eight had low-grade tumors, and two high-grade tumors. Two had surgery only, four had chemotherapy only, two had radiation only, and two had both radiation and chemotherapy. RESULTS: Progression free survival was 58% and survival was 68% at 4 years. Four patients had disease progression, of which three died. Both children with high-grade astrocytomas died. Two of eight of the children with low-grade astrocytomas of the cord recurred, one having received radiation as initial therapy and the other chemotherapy. The child, who relapsed after radiation, had a spastic quadriplegia from radiation myelitis and no salvage therapy was attempted. The four patients, all with low-grade astrocytomas, who treated with chemotherapy alone, received carboplatin and vincristine. Of these four, three are in continuous remission and one relapsed, but was salvaged with radiation. CONCLUSIONS: Chemotherapy and radiation did not benefit those with high-grade astrocytomas of the spinal cord. Good outcomes can be achieved by conservative surgery for low-grade astrocytomas of the cord when adjuvant therapy is given. Carboplatin and vincristine appeared to be effective, safe therapy for those with low-grade astrocytomas of the cord.

Measurement of tamoxifen-induced apoptosis in glioblastoma by cytometric bead analysis of active caspase-3.

Pre-clinical trials of novel drugs for the treatment of glioblastoma often use apoptosis as a measure of anti-tumor effect. Presently, there is no single reliable method to determine whether a cell is apoptotic in glioblastoma. The currently used methods for detecting apoptosis, including terminal deoxynucleotidyl transferase nick-end-labeling, nuclear morphology, DNA laddering, Annexin-V binding, and Western blotting, are subjective, difficult to perform or difficult to quantify in glioblastoma. Cytomeric bead array analysis for active caspase-3 is a recently developed technique, which may allow rapid quantitation of apoptosis in glioblastoma. Tamoxifen (TAM), a drug used in treating breast cancer and more recently for brain tumors, was used to induce apoptosis in human glioblastoma cell lines. This study showed that TAM induced apoptosis via caspase-3 activation. The results also revealed a time- and dose-dependent response of TAM induced caspase-3 activity in glioblastoma. Cytometric bead array provides a rapid technique for measuring apoptosis and the kinetics of caspase-3 activity in glioblastoma.

Cytogenetics in pediatric low-grade astrocytomas.

BACKGROUND: Cytogenetic analysis in certain tumors is a vital part of classification and assignment of prognosis. Few studies have examined the value of cytogenetic analysis in pediatric brain tumors. This is especially true of low-grade astrocytomas (LGA) of childhood. This study examines the correlation between cytogenetic abnormalities and survival in children with low-grade astrocytomas. The literature on adults with LGA suggest better survival for those whose tumors have normal cytogenetics compared to those with abnormal. We hypothesized this would also be true of children with low-grade astrocytomas. PROCEDURE: A retrospective study was performed of children presenting between 1980 and 1998 to The Children's Hospital, Denver, who had LGA and on whose tumors informative cytogenetics had obtained. RESULTS: One hundred and forty-nine children were diagnosed with histologically proven LGA. Twenty-nine had successful cytogenetic analysis. One or more chromosomal abnormalities were observed in eight tumors while normal karyotypes were observed in 21 tumors. Actuarial progression-free survival at 5 years was 87.5% for the eight children with abnormal cytogenetics and 43% for those with normal (P=0.56). Overall survival at 5 years was 83% for those with abnormal cytogenetics and 78% for those with normal (P=0.8). The differences in progression-free survival and overall survival between these two groups were not significant. Those children with WHO Grade I tumors had significantly superior progression-free and overall survival than those with Grade II tumors. CONCLUSIONS: It appears unlikely that, for children with LGA, those with normal cytogenetics have a better prognosis than those with abnormal. Histologic grade is a better predictor of outcome than cytogenetics.

Renal cell carcinoma in long-term survivors of advanced stage neuroblastoma in early childhood.

BACKGROUND: Renal cell carcinoma (RCC) is rare in children and comprises only 1-3% of all pediatric primary renal tumors. Recently, several case reports have described RCC developing in patients previously treated for advanced stage neuroblastoma (NB). METHODS AND RESULTS: Our experience with four patients treated for advanced stage NB during early childhood who developed RCC later in life are added to 14 others in the literature. CONCLUSION: These patients and our review of the literature suggest an association between RCC and NB that warrants further study.