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Biomedical subjects

B Emery

Publications and source records attributed to B Emery.

At least 19 recordsLinked to original sources

SOCS3 negatively regulates LIF signaling in neural precursor cells.

Cytokines that signal through the LIFRbeta/gp130 receptor complex, including LIF and CNTF, promote the self-renewal of embryonic and adult neural precursor cells (NPCs). In non-CNS tissues, the protein suppressor of cytokine signaling-3 (SOCS3) negatively regulates signaling through gp130. Here, we analyze the role of SOCS3 in inhibiting LIF signaling in NPCs in vitro. SOCS3 is rapidly expressed by NPCs in response to LIF stimulation, with this expression largely dependent on recruitment of STAT proteins to the activated gp130 receptor. Proliferating NPC cultures can be generated from SOCS3 knockout (SOCS3KO/KO) embryos and display prolonged STAT3 phosphorylation and induction of the GFAP gene in response to LIF. In comparison with SOCS3 wild-type (SOCS3WT/WT) NPCs, SOCS3KO/KO cultures display enhanced self-renewal capacity. However, the clonal potential of SOCS3WT/WT but not SOCS3KO/KO NPCs is enhanced by exogenous LIF. Thus, SOCS3 acts as a negative regulator of LIF signaling in NPCs.

Animals↗

Oligodendrocytes exhibit selective expression of suppressor of cytokine signaling genes and signal transducer and activator of transcription 1 independent inhibition of interferon-gamma-induced toxicity in response to leukemia inhibitory factor.

Multiple sclerosis is an autoimmune disease of the CNS that results in the death of oligodendrocytes, the myelinating cells of the CNS. Previous studies have indicated that the cytokine leukemia inhibitory factor prevents the cytotoxic effects of interferon-gamma on oligodendrocytes in vitro, and the death of oligodendrocytes in an animal model of multiple sclerosis. Members of a recently characterized family of proteins, the suppressors of cytokine signaling, have been demonstrated to mediate negative cross-talk between cytokines, with induction of suppressors of cytokine signaling proteins by one cytokine inhibiting the activity of a second. Here, we assess whether induction of members of the suppressors of cytokine signaling family could explain the antagonistic biological effects of leukemia inhibitory factor and interferon-gamma upon oligodendrocytes. It is found that leukemia inhibitory factor rapidly and strongly induces the expression of suppressors of cytokine signaling-3 in cultured rat oligodendrocytes, whereas interferon-gamma weakly induces the expression of both suppressor of cytokine signaling-1 and 3. Pre-treatment of oligodendrocytes with leukemia inhibitory factor does not prevent the subsequent phosphorylation of signal transducer and activator of transcription-1 by interferon-gamma indicating that the leukemia inhibitory factor inhibition of interferon-gamma toxicity in oligodendrocytes is mediated by a suppressor of cytokine signaling-3 independent mechanism.

Animals↗

LIF receptor signaling modulates neural stem cell renewal.

Activation of the leukemia inhibitory factor (LIF) receptor has been reported to promote gliogenesis and also to support neural stem cell (NSC) renewal. To investigate this paradox, we isolated NSCs and generated neurospheres from embryonic mice either wild-type, heterozygous, or homozygous null for LIF receptor (LIFR)-beta. Exogenous LIF abrogated neurosphere formation and promoted expression of GFAP by all cells in wild-type and heterozygous cultures. LIF also stimulated a twofold increase in the number of multipotential clones generated from these cultures in comparison with those pretreated with EGF and FGF-2 (E+F) alone. In contrast, the clonogenicity of low-density cultures of LIFR knockout cells was reduced in comparison with that of wild-type cells grown in E+F and was unaffected by LIF. Thus, although LIFR signaling is not necessary for NSC self-renewal, it enhances both the clonogenicity and the expression of GFAP by these multipotential cells.

Animals↗

Localization of the netrin guidance receptor, DCC, in the developing peripheral and enteric nervous systems.

Over recent years the secreted guidance cue, netrin-1, and its receptor, DCC, have been shown to be an essential guidance system driving axon pathfinding within the developing vertebrate central nervous system (CNS). Mice lacking DCC exhibit severe defects in commissural axon extension towards the floor plate demonstrating that the DCC-netrin guidance system is largely responsible for directing axonal projections toward the ventral midline in the developing spinal cord (Fazeli et al., Nature 386 (1997) 796). In addition, these mutants lack several major commissures within the forebrain, including the corpus callosum and the hippocampal commissure. In contrast to the CNS, the role of the DCC guidance receptor in the development of the mammalian peripheral and enteric nervous systems (PNS and ENS) has not been investigated. Here we demonstrate using immunohistochemical analysis that the DCC receptor is present in the developing mouse PNS where it is found on spinal, segmental, and sciatic nerves, and in developing sensory ganglia and their associated axonal projections. In addition, DCC is present in the ENS throughout the early developmental phase.

Animals↗

Temperature-controlled radiofrequency tissue volume reduction in the human soft palate.

OBJECTIVE: To validate the use of temperature-controlled radiofrequency energy applied to the soft palate in a multicenter setting for reduction of snoring in a minimally morbid manner. METHODS: Prospective, nonrandomized multicenter study of 113 patients who had a respiratory disturbance index less than 15 and minimum oxygen saturation not less than 85% and who were seeking treatment for habitual disruptive snoring. Patients were given either single or multiple lesions to the soft palate during each treatment session. RESULTS: Patients received 1978 J on average with an overall average of 2.4 treatments. Snoring scores went from an average of 7.8 (visual analog scale (VAS), 0-10) pretreatment to 3.2 posttreatment. Pain was minimal, averaging 1.7 (VAS 0-10) on days 1 to 6. Complications were few and transient, and mild. CONCLUSIONS: The multiple lesion protocol was the most successful; reducing snoring from 7.6 to 2.7, on a VAS with an average of 1232 J delivered over 1.6 treatments. Temperature-controlled radiofrequency was found to be a minimally invasive, well-tolerated procedure that was safe and efficacious in this study group.

Adult↗

Nasal secretion of the ozone scavenger uric acid.

Uric acid, an important scavenger of ozone, has been identified as the major low molecular weight antioxidant in baseline and cholinergically induced nasal secretions. The purpose of this study was to determine the specific tissue source of uric acid in airway secretions. The secretion of uric acid is increased by cholinergic stimulation and correlates closely with the secretion of lactoferrin (a nasal glandular protein), suggesting that submucosal glands are involved. Indeed, nasal turbinate tissue was found to contain uric acid. However, careful analysis of nasal turbinate tissue failed to reveal the presence of xanthine oxidase, the enzyme responsible for uric acid synthesis. These data suggest that uric acid might be taken up secondarily by glands from plasma. This possibility was strengthened by the observation that lowering the plasma urate level with probenecid concomitantly lowered urate secretion. These findings are consistent with the hypotheses that the principal source of uric acid in nasal secretions is plasma and that uric acid is taken up, concentrated, and secreted by nasal glands.

Albumins↗

Social and demographic characteristics of patients admitted to a palliative care unit.

In this retrospective study we reviewed the charts of 169 consecutive admissions to the Palliative Care Unit, Edmonton General Hospital. Demographic and social characteristics of patients were assessed in order to determine the likelihood that the patients could be managed at home according to currently available services. The mean age of the population was 65 +/- 12 years, 97 (57%) were women, they had a variety of cancers with major prevalence of the most frequent adult tumors, and 72% of patients were coming from acute care hospitals. Each patient had an average of 2.7 +/- 1.8 children (median = 3), a mean of 0.18 +/- 0.6 dependents (median = 0), a mean of 1 +/- 0.9 support persons at home (median = 1), and a mean of 2.6 +/- 1 support persons outside the household (median = 2). Of a total of 119 main caregivers who lived in the same household as the patient, 69 (58%) were not able to take care of the patient. Only 27 patients (16%) considered that there were major financial problems, and all 169 patients had universal health care available (95 patients had additional private health care coverage). Of 125 patients who were asked where they preferred to die, 112 (90%) stated that they did not want to die at home. Our data suggest that the lack of family support and lack of intensive home care services are the main obstacles to home care of terminally ill cancer patients in our province. Home care services as currently available are not able to care for a large number of patients with terminal cancer. More prospective research into this subject is badly needed.

Aged↗

Basal metabolic rate and diet-induced thermogenesis in Asians living in Britain.

The basal metabolic rate (BMR) and diet-induced thermogenesis (DIT) in 11 Asians (4 men, 7 women) who had lived in Britain for longer than 2 years were compared with a matched group of Europeans. The mean basal oxygen consumption was 226 ml O2/min in the Asians and 218 ml O2/min in the Europeans, values not significantly different. When BMR was expressed in absolute terms, per unit body weight, per unit body surface area or lean body mass, still no significant difference was observed. DIT was measured in the two groups fed a mixed meal containing 2800 kJ. The main increase in the metabolic rate over 20-120 min was 19 per cent in the Asians and 20 per cent in the Europeans. These results indicate that, in contrast to Asians living in the tropics, Asians living in Britain show no difference in BMR or DIT. It is concluded that Asians living in the temperature regions behave metabolically differently from those living in the tropics.

Adult↗

Effect of spiced food on metabolic rate.

Since the time of Lavoisier it has been known that the ingestion of food in animals and man produces an increase in oxygen consumption. This increase in metabolic rate was originally called 'specific dynamic action' (SDA) and is now widely referred to as the thermic effect (TE) of food or diet-induced thermogenesis (DIT) (Rothwell & Stock, 1981). Much of the early work on the thermic effect was confined to the type and amount of food, notably the macronutrients--proteins, fats and carbohydrates. Later, it was shown that certain minor constituents of the diet such as caffeine and associated methylxanthines (Zahorska-Markrewicz, 1980; Jung et al., 1981) in tea and coffee could also have a profound effect on metabolic rate. The consumption of alcohol was also shown to increase metabolic rate (Rosenberg & Durnin, 1978). The work described in this paper reports the effect of another minor constituent of food, spices, on metabolic rate. Although the use of spices in our food has steadily increased with time little information exists on their effect on the metabolic rate. It has been estimated that approximately 40 different spices are used in our diet today. This communication reports the effect of chilli (red pepper, capsicum annuum) and mustard (Brassica juncea).

Adult↗

Armamentarium.

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Dental Instruments↗