3D Transcranial ultrasound localization microscopy reveals major arteries in the sheep brain.

Cerebral circulation ensures the proper functioning of the entire human body, and its interruption, i.e. stroke, leads to irreversible damage.

An updated model of hydrocephalus in sheep to evaluate the performance of a device for ambulatory wireless monitoring of cerebral pressure through shunts.

Background: Cerebrospinal fluid (CSF) diversion by shunts is the most common surgical treatment for hydrocephalus. Though effective, shunts are associated with risk of dysfunction leading to multiple surgical revisions, affecting patient quality-of-life and incurring high healthcare costs. There is a need for ambulatory monitoring systems for life-long assessment of shunt status.

Chronic social stress alters protein metabolism in juvenile rainbow trout, Oncorhynchus mykiss.

When confined in pairs, juvenile rainbow trout (Oncorhynchus mykiss) form dominance hierarchies in which subordinate fish exhibit characteristic physiological changes including reduced growth rates and chronically elevated plasma cortisol concentrations. We hypothesized that alterations in protein metabolism contribute to the reduced growth rate of socially stressed trout, and predicted that subordinate trout would exhibit reduced rates of protein synthesis coupled with increases in protein degradation. Protein metabolism was assessed in dominant and subordinate fish after 4 days of social interaction, and in fish that were separated after 4 days of interaction for a 4 days recovery period, to determine whether effects on protein metabolism recovered when social stress was alleviated.

Modification of apparent intracerebral hematoma volume on T2-weighted images during normobaric oxygen therapy may contribute to false diagnosis.

It was previously reported that normobaric oxygen therapy (NBO) significantly affected T2-weighted imaging in a mouse model of intracerebral hemorrhage (ICH). However, it is unclear whether a similar phenomenon exists in large volume ICH as seen in human pathology. We investigated the effects of NBO on T2-weighted images in a pig model of ICH.

Adjustments of Protein Metabolism in Fasting Arctic Charr, Salvelinus alpinus.

Protein metabolism, including the interrelated processes of synthesis and degradation, mediates the growth of an animal. In ectothermic animals, protein metabolism is responsive to changes in both biotic and abiotic conditions. This study aimed to characterise responses of protein metabolism to food deprivation that occur in the coldwater salmonid, Arctic charr, Salvelinus alpinus.

A rapid and convenient method for measuring the fractional rate of protein synthesis in ectothermic animal tissues using a stable isotope tracer.

A method was devised to measure the fractional rate of protein synthesis in fish using a stable isotope labelled tracer (ring-D5-phenylalanine) instead of radioactive phenylalanine. This modified flooding dose technique utilizes gas chromatography with mass spectrometry detection (GC-MS). The technique was validated by measuring the fractional rate of protein synthesis in the liver and white muscle of Arctic charr (Salvelinus alpinus) and then tested by comparing the fractional rate of protein synthesis of fed and starved Arctic charr.

High resolution 3T fMRI in anesthetized monkeys.

Although there are numerous 3T MRI research devices all over the world, only a few functional studies at 3T have been done in anesthetized monkeys. In the past, anesthetized preparations were reported to be misleading when exploring cortical brain regions outside the primary sensory areas. Nonetheless, a great improvement has been achieved in the limited effect of anesthetic agents on the reactivity of the brain.

Comparison of the effects of erythropoietin and its carbamylated derivative on behaviour and hippocampal neurogenesis in mice.

Erythropoietin (EPO), a well known haematopoietic growth factor, possesses neuroprotective and neurotrophic effects which have been recently reported to improve cognition and to modulate emotional processing. We investigated the effects of EPO and of its non-erythropoietic carbamylated derivative (CEPO) on memory- and emotion-related behaviour in the adult mouse. Locomotor activity, memory performances (place and object recognition tasks), anxiety- (light/dark transition test) and despair-like behaviours (tail suspension test) were assessed over 6 weeks of repeated EPO or CEPO administration (40 μg/kg, twice a week).

Further evaluation of antecedent interventions on compliance: the effects of rationales to increase compliance among preschoolers.

Functional analyses were conducted to identify reinforcers for noncompliance exhibited by 6 young children. Next, the effects of rationales (statements that describe why a child should comply with a caregiver-delivered instruction) were evaluated. In Experiment 1, 3 participants received the rationales immediately after the therapist's instruction.

Permanent or transient chronic ischemic stroke in the non-human primate: behavioral, neuroimaging, histological, and immunohistochemical investigations.

Using multimodal magnetic resonance imaging (MRI), behavioral, and immunohistochemical analyses, we examined pathological changes at the acute, sub-acute, and chronic stages, induced by permanent or temporary ischemia in the common marmoset. Animals underwent either permanent (pMCAO) or 3-h transient (tMCAO) occlusion of the middle cerebral artery (MCAO) by the intraluminal thread approach. MRI scans were performed at 1 h, 8, and 45 days after MCAO.

Delayed hypoxic postconditioning protects against cerebral ischemia in the mouse.

Background And Purpose: Inspired from preconditioning studies, ischemic postconditioning, consisting of the application of intermittent interruptions of blood flow shortly after reperfusion, has been described in cardiac ischemia and recently in stroke. It is well known that ischemic tolerance can be achieved in the brain not only by ischemic preconditioning, but also by hypoxic preconditioning. However, the existence of hypoxic postconditioning has never been reported in cerebral ischemia.

Intraluminal thread model of focal stroke in the non-human primate.

The common marmoset (Callithrix jacchus), a New World monkey, has recently been used as a model of focal cerebral ischaemia. Here, we sought to develop a stroke model in this species using an intraluminal approach to occlude the middle cerebral artery (MCA). This technically simple procedure allows both transient and permanent ischaemia with minimal morbidity.

Delayed administration of deferoxamine reduces brain damage and promotes functional recovery after transient focal cerebral ischemia in the rat.

The mechanisms underlying functional recovery after stroke are poorly understood. Brain-adaptive responses to the hypoxic stress elicited by ischemia could contribute to these mechanisms. Indeed, hypoxia-inducible factor-1 (HIF-1), one of the main transcriptional factors regulated by oxygen level, increases the expression of several beneficial genes such as erythropoietin, glucose transporter-1 and vascular endothelial growth factor.

Dominant-negative beta1 integrin mice have region-specific myelin defects accompanied by alterations in MAPK activity.

Recent studies have demonstrated the importance of beta1 integrin in oligodendrocyte maturation in vitro. Similar studies in vivo have been difficult due to the embryonic and perinatal lethality of null mutations in integrin subunits. Here, we have generated transgenic mouse models that overexpress full length beta1 integrin or express a dominant-negative beta1 integrin DeltaC (lacking the C-terminal tail) under the control of the proteolipid protein (PLP) promoter.

Alterations in myelination in the central nervous system of dystonia musculorum mice.

Dystonia musculorum (dt) is an autosomal recessive sensory neuropathy in mice resulting from a mutation in the gene encoding the cytoskeletal linker protein Bpag1. In addition to neurodegeneration, dt mice display myelination abnormalities in the peripheral nervous system. In this report we investigated whether myelination abnormalities are also present in the central nervous system of dt(Tg4) mice.

Interactions between protein kinase CK2 and Pin1. Evidence for phosphorylation-dependent interactions.

The peptidyl-prolyl isomerase Pin1 interacts in a phosphorylation-dependent manner with several proteins involved in cell cycle events. In this study, we demonstrate that Pin1 interacts with protein kinase CK2, an enzyme that generally exists in tetrameric complexes composed of two catalytic CK2 alpha and/or CK2 alpha' subunits together with two regulatory CK2 beta subunits. Our results indicate that Pin1 can interact with CK2 complexes that contain CK2 alpha.

Functional specialization of CK2 isoforms and characterization of isoform-specific binding partners.

In mammals, protein kinase CK2 has two isozymic forms of its catalytic subunit, designated CK2alpha and CK2alpha'. CK2alpha and CK2alpha' exhibit extensive similarity within their catalytic domains but have completely unrelated C-terminal sequences. To systematically examine the cellular functions of each CK2 isoform in mammalian cells, we have generated human osteosarcoma U2-OS cell lines with the expression of active or inactive versions of each CK2 isoform under the control of an inducible promoter.

Identification and characterization of CKIP-1, a novel pleckstrin homology domain-containing protein that interacts with protein kinase CK2.

The catalytic subunits of protein kinase CK2, CK2alpha and CK2alpha', are closely related to each other but exhibit functional specialization. To test the hypothesis that specific functions of CK2alpha and CK2alpha' are mediated by specific interaction partners, we used the yeast two-hybrid system to identify CK2alpha- or CK2alpha'-binding proteins. We report the identification and characterization of a novel CK2-interacting protein, designated CKIP-1, that interacts with CK2alpha, but not CK2alpha', in the yeast two-hybrid system.

Cooperative effect of hepatocyte growth factor and fibronectin in anchorage-independent survival of mammary carcinoma cells: requirement for phosphatidylinositol 3-kinase activity.

Anchorage-independent survival and growth are critical characteristics of malignant cells. We showed previously that the addition of exogenous hepatocyte growth factor (HGF) and the presence of fibronectin fibrils stimulate anchorage-independent colony growth of a murine mammary carcinoma, SP1, which expresses both HGF and HGF receptor (Met; R. Saulnier et al.

Inducible expression of protein kinase CK2 in mammalian cells. Evidence for functional specialization of CK2 isoforms.

Protein kinase CK2 (formerly casein kinase II) exhibits elevated expression in a variety of cancers, induces lymphocyte transformation in transgenic mice, and collaborates with Ha-Ras in fibroblast transformation. To systematically examine the cellular functions of CK2, human osteosarcoma U2-OS cells constitutively expressing a tetracycline-regulated transactivator were stably transfected with a bidirectional plasmid encoding either catalytic isoform of CK2 (i.e.

c-Src kinase activity is required for hepatocyte growth factor-induced motility and anchorage-independent growth of mammary carcinoma cells.

Overexpression and amplification of hepatocyte growth factor (HGF) receptor (Met) have been detected in many types of human cancers, suggesting a critical role for Met in growth and development of malignant cells. However, the molecular mechanism by which Met contributes to tumorigenesis is not well known. The tyrosine kinase c-Src has been implicated as a modulator of cell proliferation, spreading, and migration; these functions are also regulated by Met.

The role of integrins and extracellular matrix in anchorage-independent growth of a mammary carcinoma cell line.

Anchorage-independent growth is a property of malignant cells. Extracellular matrix proteins are present in tumor spheroids but their function is not clearly defined. In this paper we show that a murine mammary carcinoma cell line, SP1, which expresses the fibronectin receptor alpha 5 beta 1 requires fibronectin for anchorage-independent growth in soft agar.

Fibronectin fibrils and growth factors stimulate anchorage-independent growth of a murine mammary carcinoma.

Stromal cells are important regulators of mammary carcinoma growth and metastasis. We have previously shown that a 3T3-L1 adipocyte cell line secretes hepatocyte growth factor (HGF), which stimulates proliferation of a murine mammary carcinoma (SP1) in monolayer cultures (DNA Cell Biol. 13, 1189-1897, 1994).

Role of hepatocyte growth factor in breast cancer: a novel mitogenic factor secreted by adipocytes.

Stromal cells can dramatically affect the growth and metastatic capability of breast carcinoma cells. Growth factors, considered to be important mediators of this process, act as either mitogenic or mito-inhibitory regulators. We have developed an in vitro coculture system to examine the influence of adipocytes, a dominant mammary stromal cell type, on the growth of a murine mammary carcinoma, SP1.

Specific alterations in the expression of alpha 3 beta 1 and alpha 6 beta 4 integrins in highly invasive and metastatic variants of human prostate carcinoma cells selected by in vitro invasion through reconstituted basement membrane.

Highly invasive cell subpopulations from a human prostate carcinoma cell line, PC-3, were selected for by allowing the parental PC-3 cells to invade through reconstituted basement membrane, Matrigel. These cells were collected, cultured and then selected further by repeated invasion through the in vitro invasion chamber. The invasive subpopulations (I-PC3 (2) and (3)) were found to be approximately 15-fold more invasive in vitro than the parental cells, had a distinct rounded morphology in culture, and proliferated more rapidly than the parental cells.