Microglia express functional 11β‐hydroxysteroid dehydrogenase type 1

Glucocorticoids are potent regulators of inflammation exerting permissive, stimulatory, and suppressive effects. Glucocorticoid access to intracellular receptors is regulated by the activity of two distinct enzymes known as 11β‐hydroxysteroid dehydrogenase (11βHSD) Type 1 and Type 2, which catalyze the activation or deactivation of glucocorticoids. Although expression of these enzymes in major organ systems and their roles in the metabolic effects of glucocorticoids have been described, their role in the inflammatory response has only recently started to be addressed. In this report, we have studied the expression and activity of 11βHSD Type 1 and Type 2 in microglia cells. Microglia, the brain's resident macrophages, initiate and orchestrate CNS inflammatory responses. Importantly, activated microglia are implicated in most neurodegenerative conditions, making them key subjects of study. We found that microglia expressed 11βHSD‐1, but not 11βHSD‐2, both in ex vivo FACS‐sorted adult cells and in vitro primary cultures. 11βHSD‐1 expression was increased in LPS‐activated microglia. Moreover, 11βHSD‐1 catalyzed the metabolic conversion of 11‐dehydro‐corticosterone into corticosterone (CORT), which potently reduced cytokine production in activated microglia. We propose that 11βHSD‐1 may provide microglia with an intrinsic mechanism to autoregulate and inhibit proinflammatory mediator production through CORT formation. © 2010 Wiley‐Liss, Inc.     

Peripheral white blood cells and HPA axis neurohormones in major depression

Alterations in peripheral blood leukocyte distribution in major depression, including leukocytosis, neurotrophilia and lymphopenia, have been described. To assess peripheral white blood cells and the hypothalamic-pituitary (HP) axis in drug-free patients with major depression, we measured the total white blood cell count (WBC), and percentage of lymphocytes, and the plasma levels of cortisol, adrenocorticotropic hormone (ACTH), growth hormone (GH) and prolactin (PRL). Twenty male patients with major depression had relative lymphopenia and leukocytosis when compared with 20 age, sex and racematched control subjects. Elevated Beck and Hamilton depression scores correlated with a decreased percentage of lymphocytes, in a group of all subjects combined. There was a weak tendency for elevated growth hormone to correlate with relative lymphopenia in the control subjects only. Relative lymphopenia and leukocytosis may be a part of the psychobiology of major depression.     

Epidermal growth factor-dependent enhancement of axonal regeneration in the pond snail Lymnaea stagnalis: role of phagocyte survival

Peripheral nerve injury triggers complex responses from neuronal as well as from multiple nonneuronal cell types. These responses are coordinated by a wide spectrum of secreted and nonsecreted factors, including growth factors, cytokines, and cell adhesion molecules. These molecules originate from different sources and act both locally at the site of injury as well as centrally at the location of the neuronal cell bodies. One of the signal systems frequently implicated in this process is the epidermal growth factor (EGF) family and its receptors. Expression of members of this family as well as that of EGF-receptors is upregulated in different cell types after peripheral nerve injury. However, the functional significance of this response is unclear. Using a simple invertebrate model system (Lymnaea stagnalis), the present study implicates the EGF/EGF-receptor system in the survival of ionized calcium-binding adaptor molecule 1 (Iba1)-positive phagocytes that reside in the nervous system. We show that inhibiting the EGF-signaling pathway enhances cell death in this type of cell, an effect paralleled by a substantial reduction in axonal regeneration. Therefore, complementing our previous observation that Lymnaea EGF provides trophic support to axotomized neurons, the present results emphasize the significance of nonneuronal actions of EGF receptor ligands in axonal regeneration. Thus, we add a novel perspective to the ongoing discussion on the functional significance of the EGF signaling system in the injury responses of the nervous system.     

Identification of candidate disease genes by EST alignments, synteny, and expression and verification of Ensembl genes on rat chromosome 1q43-54

We aligned Incyte ESTs and publicly available sequences to the rat genome and analyzed rat chromosome 1q43-54, a region in which several quantitative trait loci (QTLs) have been identified, including renal disease, diabetes, hypertension, body weight, and encephalomyelitis. Within this region, which contains 255 Ensembl gene predictions, the aligned sequences clustered into 568 Incyte genes and gene fragments. Of the Incyte genes, 261 (46%) overlapped 184 (72%) of the Ensembl gene predictions, whereas 307 were unique to Incyte. The rat-to-human syntenic map displays rearrangement of this region on rat chr. 1 onto human chromosomes 9 and 10. The mapping of corresponding human disease phenotypes to either one of these chromosomes has allowed us to focus in on genes associated with disease phenotypes. As an example, we have used the syntenic information for the rat Rf-1 disease region and the orthologous human ESRD disease region to reduce the size of the original rat QTL to only 11.5 Mb. Using the syntenic information in combination with expression data from ESTs and microarrays, we have selected a set of 66 candidate disease genes for Rf-1. The combination of the results from these different analyses represents a powerful approach for narrowing the number of genes that could play a role in the development of complex diseases.     

Dopamine activates two different receptors to produce variability in sign at an identified synapse

Chemical synaptic transmission was investigated at a central synapse between identified neurons in the freshwater snail, Lymnaea stagnalis. The presynaptic neuron was the dopaminergic cell, Right Pedal Dorsal one (RPeD1). The postsynaptic neuron was Visceral Dorsal four (VD4). These neurons are components of the respiratory central pattern generator. The synapse from RPeD1 to VD4 showed variability of sign, i.e., it was either inhibitory (monophasic and hyperpolarizing), biphasic (depolarizing followed by hyperpolarizing phases), or undetectable. Both the inhibitory and biphasic synapse were eliminated by low Ca2+/high Mg2+ saline and maintained in high Ca2+/high Mg2+ saline, indicating that these two types of connections were chemical and monosynaptic. The latency of the inhibitory postsynaptic potential (IPSP) in high Ca2+/high Mg2+ saline was approximately 43 ms, whereas the biphasic postsynaptic potential (BPSP) had approximately 12-ms latency in either normal or high Ca2+/high Mg2+ saline. For a given preparation, when dopamine was pressured applied to the soma of VD4, it always elicited the same response as the synaptic input from RPeD1. Thus, for a VD4 neuron receiving an IPSP from RPeD1, pressure application of dopamine to the soma of VD4 produced an inhibitory response similar to the IPSP. The reversal potentials of the IPSP and the inhibitory dopamine response were both approximately -90 mV. For a VD4 neuron with a biphasic input from RPeD1, pressure-applied dopamine produced a biphasic response similar to the BPSP. The reversal potentials of the depolarizing phase of the BPSP and the biphasic dopamine response were both approximately -44 mV, whereas the reversal potentials for the hyperpolarizing phases were both approximately -90 mV. The hyperpolarizing but not the depolarizing phase of the BPSP and the biphasic dopamine response was blocked by the D-2 dopaminergic antagonist (+/-) sulpiride. Previously, our laboratory demonstrated that both IPSP and the inhibitory dopamine response are blocked by (+/-) sulpiride. Conversely, the depolarizing phase of both the BPSP and the biphasic dopamine response was blocked by the Cl- channel antagonist picrotoxin. Finally, both phases of the BPSP and the biphasic dopamine response were desensitized by continuous bath application of dopamine. These results indicate that the biphasic RPeD1 --> VD4 synapse is dopaminergic. Collectively, these data suggest that the variability in sign (inhibitory vs. biphasic) at the RPeD1 --> VD4 synapse is due to activation of two different dopamine receptors on the postsynaptic neuron VD4. This demonstrates that two populations of receptors can produce two different forms of transmission, i.e., the inhibitory and biphasic forms of the single RPeD1 --> VD4 synapse.     

Innervation of the thymus gland by brain stem and spinal cord in mouse and rat

Central nervous system (CNS) projections to the thymus were studied in the mouse and rat using the horseradish peroxidase (HRP)-retrograde transport method. With discrete HRP injections localized to the thymus, labeled neurons are evident in both medulla and spinal cord. In the medulla the largest population of labeled neurons is present in the retrofacial nucleus. Within this cytoarchitectonically distinct nucleus, the majority of neurons are labeled with large HRP injections in the thymus. In addition to retrofacial nucleus, scattered labeled neurons are found throughout the rostrocaudal extent of the nucleus ambiguus and in the dorsal medullary tegmentum adjacent to the dorsal motor vagus nucleus. With HRP injections restricted to thymus parenchyma, no labeled neurons are evident in the dorsal motor vagus nucleus. Three groups of spinal cord neurons are labeled. In segments C2–C4, neurons localized to the ventral horn are labeled in two distinct columns, one located lying laterally in the ventral horn and the other located medially. Labeling of neurons in these segments is distinct from that of large motor neurons located medially in the ventral horn extending from the level of the decussation of the pyramids through the C1 segment. The location and sizes of neurons labeled in these areas following HRP injection in the thymus are identical in the mouse and rat. These observations provide evidence for previously unknown projections from spinal cord and brain stem to the thymus which may play an important role in the regulation of thymic function.     

The treatment of pulmonary Wangiella dermatitidis infection with oral voriconazole

What is known and Objective: Wangiella dermatitidis is a darkly pigmented fungus that has been isolated from the soil, dead plant material and areas of high humidity. Infection from the pathogen has not been extensively documented and few published cases report survival. Of the antifungal agents used in previous reports, none has been proven to improve outcomes. Voriconazole is known to have in vitro activity against the organism, but clinical experience for the treatment of W. dermatitidis infection is limited. The objective of this case report is to describe the use of voriconazole for the treatment of W. dermatitidis infection. Case summary: An 86‐year‐old American woman with a past medical history significant only for mild dementia is successfully treated for pulmonary W. dermatitidis infection using oral voriconazole monotherapy with minimal adverse effects. What is new and Conclusion: Voriconazole appears to be effective as monotherapy for the treatment of pulmonary W. dermatitidis infections. A minimum of 3–4 months of antifungal treatment should be given. Adverse effects with prolonged voriconazole use do not appear to be a barrier to treatment.     

Using appendicitis scores in the pediatric ED

Study Objective

The aims of the study were to prospectively evaluate the Alvarado and Samuel (pediatric appendicitis score [PAS]) appendicitis scoring systems in children and determine performance based on sex.

Methods

Children with abdominal pain concerning for appendicitis were recruited. Nine parameters evaluated by the scores were documented before imaging/surgery consultation. Test characteristics were calculated on all patients and by sex.

Results

Two hundred eighty-seven patients enrolled; median age was 9.8 years; and 155 (54%) were diagnosed with pathologic examination-confirmed appendicitis. Patients with appendicitis had mean PAS of 7.6, and those without had mean of 5.6 (P < .001). Patients with appendicitis had a mean Alvarado of 7.2, and those without had a mean of 5.2 (P < .001). In appendicitis patients, PAS cutoff of 6 or greater would give 137 correct diagnoses; sensitivity, 88%; specificity, 50%; and positive predictive value (PPV), 67%. An Alvarado cutoff of 7 or greater would give 118 correct diagnoses; sensitivity, 76%; specificity, 72%; and PPV, 76%. Both performed better in males than females.

Conclusion

Regardless of sex, neither PAS nor Alvarado has adequate predictive values for sole use to diagnose appendicitis.