Reelin-immunoreactivity in the hippocampal formation of 9-month-old wildtype mouse: effects of APP/PS1 genotype and ovariectomy

Reelin, an extracellular matrix protein has an important role in the migration, correct positioning and maturation of neurons during development. Though it is generally down-regulated in the postnatal period, expression of this large glycoprotein continues in the adult brain in some cell populations. In the present study, we examined the distribution of reelin-immunoreactivity (-ir) in the hippocampal formation of 9-month-old wildtype mice (WT). Then, reelin-ir in normal mice was compared to that of transgenic mice (APP/PS1) carrying mutated human APP and PS1 genes, which are linked to the familial form of Alzheimer's disease (AD). The APP/PS1 mice were additionally burdened with a second risk factor for AD, namely depletion of circulating gonadal hormones by ovariectomy (APP/PS1 + OVX). The analyses revealed that in adult WT reelin-ir is expressed by Cajal-Retzius cells and a subgroup of interneurons throughout the hippocampal formation. In addition, layer II projection neurons in the lateral entorhinal subfields are reelin-ir. Interestingly, ovariectomy decreases the number of reelin-ir cells in the hilus in WT mice, whereas AD-related genotype alone induces only a non-significant reduction. Unexpectedly, additional stress, e.g., depletion of gonadal hormones, does not aggravate the slight reduction in the reelin cell number in the APP/PS1 mice. We propose that the changes in normal reelin-ir are linked to disturbances in repair mechanisms in which APP/PS1 and gonadal hormones are involved and which are perturbed in neurodegenerative conditions, namely AD.     

Expression of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 (KDR/Flk-1) in ischemic skeletal muscle and its regeneration

Vascular endothelial growth factor (VEGF) is a hypoxia-inducible endothelial cell mitogen and survival factor. Its receptor VEGFR-2 (KDR/Flk-1) mediates these effects. We studied the expression of VEGF and VEGFR-2 in ischemic human and rabbit skeletal muscle by immunohistochemistry and in situ hybridization. Human samples were obtained from eight lower limb amputations because of acute or chronic critical ischemia. In chronically ischemic human skeletal muscle VEGF and VEGFR-2 expression was restricted to atrophic and regenerating skeletal myocytes, whereas in acutely ischemic limbs VEGF and VEGFR-2 were expressed diffusely in the affected muscle. Hypoxia-inducible factor-1alpha was associated with VEGF and VEGFR-2 expression both in acute and chronic ischemia but not in regeneration. Hindlimb ischemia was induced in 20 New Zealand White rabbits by excising the femoral artery. Magnetic resonance imaging and histological sections revealed extensive ischemic damage in the thigh and leg muscles of ischemic rabbit hindlimbs with VEGF expression similar to acute human lower limb ischemia. After 1 and 3 weeks of ischemia VEGF expression was restricted to regenerating myotubes and by 6 weeks regeneration and expression of VEGF was diminished. VEGFR-2 expression was co-localized with VEGF expression in regenerating myotubes. Macrophages and an increased number of capillaries were associated with areas of ischemic muscle expressing VEGF and VEGFR-2. In conclusion, two patterns of VEGF and VEGFR-2 expression in human and rabbit ischemic skeletal muscle are demonstrated. In acute skeletal muscle ischemia VEGF and VEGFR-2 are expressed diffusely in the affected muscle. In chronic skeletal muscle ischemia and in skeletal muscle recovering from ischemia VEGF and VEGFR-2 expression are restricted to atrophic and regenerating muscle cells suggesting the operation of an autocrine pathway that may promote survival and regeneration of myocytes.     

Fixation of femoral shaft osteotomy with an intramedullary composite rod: an experimental study on dogs with a two-year follow-up

A novel composite material with an ultra-high strength and a low elastic modulus called carbon fibre-reinforced liquid crystalline polymer (LCP/CF) has been developed. An experimental diaphyseal osteotomy of the proximal femur in fourteen Beagle dogs was fixed with an intramedullary LCP/CF rod of 4.5 mm in diameter and 80 mm in length. The radiological follow-up intervals were 1, 3, 6, 12, 24, 52, and 104 weeks. Five dogs were killed at 1 year and three dogs at 2 years for histological studies; six dogs were retained for longer follow-up. Radiographs showed an uncomplicated healing of the diaphyseal osteotomy with an external callus formation in all dogs in 12 weeks. Histological analysis revealed a benign host tissue response with few inflammatory cells. Both bone and fibrous tissue were seen at the LCP/CF-host tissue interface. The cross-sectional cortical area of the operated femur was slightly greater than that of the control femur in the 2-year follow-up. LCP/CF showed promising properties for high-load applications.     

Using Emergency Obstetric Drills in Maternity Units as a Performance Improvement Tool

ABSTRACT: Background: Obstetric drills are being used increasingly to test, improve, and maintain knowledge and skills related to obstetric emergencies as a means to improve proficiency and efficiency of practitioners. The purpose of this study was to assess the feasibility and usefulness of conducting drills to evaluate the response to obstetric emergencies using a holistic approach that tested the hospital system. Methods: A prospective trial was conducted at three hospitals (two tertiary referral centers and one small community hospital) in Beirut, Lebanon. Two different emergency obstetric drills at two points in time were conducted between April and May 2006 either in the emergency room or on the labor floor. The drills included medical and paramedical staff, a female actor (simulating a pregnant woman), a research assistant (acting as her companion), and a physician trained in obstetrics (the drill leader). Responses were recorded and critically analyzed. Results: Although overall quality of care was within standards of care, problems were identified related to hospital policies, supplies and equipment, communication, and clinical management. Some technical problems related to administration of the drills were identified. Most drill participants appreciated the exercise and found it beneficial. Conclusions: Obstetric drills provide a useful tool to identify and address deficiencies in the hospital system. This finding could have implications on improving quality of care provided to obstetric patients. (BIRTH 36:1 March 2009)     

Copy number alterations and neoplasia‐specific mutations in MELK,PDCD1LG2, TLN1, and PAX5 at 9p in different neoplasias

Genetic alterations affecting 9p are commonly present in many cancer types and many cancer‐related genes are located in this chromosomal region. We sequenced all of the genes located in a 32Mb region of 9p by targeted next generation sequencing (NGS) in 96 patients with different cancer types, including acute lymphoblastic leukemia, bone malignant fibrous histiocytoma/undifferentiated pleomorphic sarcoma, fibrosarcoma, Ewing's sarcoma, and lung carcinoma. Copy number alterations (CNA), and mutations were studied from the NGS data. We detected a deletion at the CDKN2A locus as being the most frequent genetic alteration in all cancer types. In addition to this locus, NGS also identified other small regions of copy number loss and gain. However, different cancer types did not reveal any statistically significant differences with regard to CNA frequency or type. Of the 191 genes within the target region, two novel recurrent mutations were found in the MELK and PDCD1LG2 genes. The most commonly mutated gene in sarcomas was TLN1 (8%) and PAX5 in ALL (9%). Mutations in PAX5, and RUSC2, were seen exclusively in ALL patients and those in KIAA1432, CA9, TLN1, and MELK only in sarcomas (MFH, FS, EFT). Thus using targeted NGS of the 9p region, in addition to commonly deleted CDKN2A locus, we were able to identify a number of small deletions and gains, as well as novel recurrent mutations in different cancer types. © 2014 Wiley Periodicals, Inc.