Microglial contribution to synaptic uptake in the prefrontal cortex in schizophrenia.

Microglia in human post-mortem tissue in schizophrenia patients' brains engulf synaptic material, but not differently to age-matched non-neurological control brains. Also, schizophrenia brains display similar levels of microgliosis to control brains.

Delineation of gliomas using radial metabolite indexing.

(1) H MRSI has demonstrated the ability to characterise and delineate brain tumours, but robust data analysis methods are still needed. In this study, we present an objective analysis method for MRSI data to delineate tumour abnormality regions. The presented method is a development of the choline-to-N-acetylaspartate index (CNI), which uses perpendicular distances in a choline versus N-acetylaspartate plot as a measure of abnormality. We propose a radial CNI (rCNI) method that uses the choline to N-acetylaspartate ratio directly as an abnormality measure. To avoid problems with small or zero denominators, we perform an arctangent transformation. CNI abnormality contours were evaluated using a z-score threshold of 2 (CNI2) and 2.5 (CNI2.5) and compared with rCNI2. Simulations modelling low-grade (LGG) and high-grade (HGG) gliomas with different tissue compartments and partial volume effects suggest improved specificity of rCNI2 (LGG 92%/HGG 91%) over CNI2 (LGG 69%/HGG 69%) and CNI2.5 (LGG 74%/HGG 75%), whilst retaining a similar sensitivity to both CNI2 and CNI2.5. Our simulation results also confirm a previously reported increase in specificity of CNI2.5 over CNI2 with little penalty in sensitivity. The analysis of MRSI data acquired from 10 patients with low-grade glioma at 3 T suggests a more robust delineation of the lesions using rCNI with respect to conventional imaging compared with standard CNI. Further analysis of 29 glioma datasets acquired at 1.5 T, together with previously published estimated tumour proportions, suggests that rCNI has higher sensitivity and specificity for the identification of abnormal MRSI voxels.

Neurologic melioidosis in an imported pigtail macaque (Macaca nemestrina).

Burkholderia pseudomallei is the cause of melioidosis in humans and other animals. Disease occurs predominately in Asia and Australia. It is rare in North America, and affected people and animals typically have a history of travel to (in human cases) or importation from (in animal cases) endemic areas. We describe the gross and histopathologic features and the microbiologic, molecular, and immunohistochemical diagnoses of a case of acute meningoencephalomyelitis and focal pneumonia caused by B. pseudomallei infection in a pigtail macaque that was imported from Indonesia to the United States for research purposes. This bacterium has been classified as a Tier 1 overlap select agent and toxin; therefore, recognition of pathologic features, along with accurate and timely confirmatory diagnostic testing, in naturally infected research animals is imperative to protect animals and personnel in the laboratory animal setting.

An extended role for CT in the emergency diagnosis of malignant spinal cord compression.

AIM: To evaluate the usefulness of computed tomography (CT) for triaging between urgent transfer to a neurosurgical unit and delayed magnetic resonance imaging (MRI) in the local hospital. MATERIALS AND METHODS: Radiologists blinded to the MRI findings scored CT images from 1-5 using a novel grading system based on the degree of cord compression observed in 44 patients. Seventy separate levels were scored. The observers' CT scores were compared with the MRI findings. All scoring radiologists were specialist registrars at different stages of training. RESULTS: Agreement between CT and MRI scores for metastatic spinal cord compression (MSCC) were high with Cohen's weighted Kappa score 0.70 (p<0.001, 95% CI 0.65 to 0.75). CT has a sensitivity of 89% and specificity of 92% for MSCC. Half the false-positive and false-negative results came from a single junior radiologist who would not normally report CT or MRI studies unsupervised. The best CT-MRI agreement was from the most senior trainee radiologist. CONCLUSIONS: Spinal findings on routine staging whole-body CT combined with clinical findings are sufficient to determine which patients with MSCC can safely wait for MRI the next working day at the local hospital and those who need emergency transfer to a neurosurgical unit for MRI and possible surgical decompression.

The protracted Holocene extinction of California's flightless sea duck (Chendytes lawi) and its implications for the Pleistocene overkill hypothesis.

Bones of the flightless sea duck (Chendytes lawi) from 14 archaeological sites along the California coast indicate that humans hunted the species for at least 8,000 years before it was driven to extinction. Direct (14)C dates on Chendytes bones show that the duck was exploited on the southern California islands as early as approximately 11,150-10,280 calendar years B.P., and on the mainland by at least 8,500 calendar years B.P. The youngest direct date of 2,720-2,350 calendar years B.P., combined with the absence of Chendytes bones from hundreds of late Holocene sites, suggests that the species was extinct by approximately 2,400 years ago. Although the extinction of Chendytes clearly resulted from human overhunting, its demise raises questions about the Pleistocene overkill model, which suggests that megafauna were driven to extinction in a blitzkrieg fashion by Native Americans approximately 13,000 years ago. That the extermination of Chendytes was so protracted and archaeologically visible suggests that, if the terminal Pleistocene megafauna extinctions were primarily the result of human exploitation, there should also be a long and readily detectable archaeological record of their demise. The brief window now attributed to the Clovis culture ( approximately 13,300-12,900 B.P.) seems inconsistent with an overhunting event.

Descriptive assessment of adverse events associated with midazolam-etomidate versus saline-etomidate in healthy hydromorphone premedicated dogs.

OBJECTIVES: To determine the frequency, severity and duration of adverse events including myoclonus, pain on injection, hypersalivation, regurgitation and apnoea after administration of midazolam or saline followed by etomidate in hydromorphone premedicated dogs. MATERIALS AND METHODS: Dogs undergoing elective dental prophylaxis or soft tissue surgeries were enrolled in this randomised trial. Dogs were premedicated with hydromorphone 0.1 mg/kg IV. Sixty seconds later, midazolam 0.3 mg/kg or saline at an equivalent volume was administered IV. Sixty seconds after that, etomidate 1.5 mg/kg IV was administered over 60 seconds. Additional doses of 0.5 mg/kg etomidate were administered until endotracheal intubation was successful. Observers were blinded to the treatment. Frequency, duration and a severity score of 0 to 3 were recorded for myoclonus, pain on injection, hypersalivation and regurgitation. Duration of apnoea and frequency of any additional complications was recorded. RESULTS: Forty variable breed healthy dogs were enrolled in the study. Myoclonus, pain on injection, regurgitation, hypersalivation, gagging, tachypnoea and pigmenturia occurred, respectively, in 10%, 40%, 0%, 15%, 35%, 25% and 5% of dogs in the saline group and 0%, 65%, 0%, 10%, 45%, 15% and 5% of dogs in the midazolam group. Apnoea occurred for 115 seconds (range 0 to 660 seconds) and 160 seconds (range 0 to 600 seconds) in the saline and midazolam groups, respectively. Two dogs developed pigmenturia. The trial was stopped early due to the occurrence of pigmenturia. CLINICAL SIGNIFICANCE: Due to early stopping of the trial, the predefined sample size was not reached. Further investigation is needed to determine if midazolam reduced the incidence of adverse events or improved the induction quality when combined with hydromorphone and etomidate.

Amino- and carboxy-terminal deletion mutants of Gs alpha are localized to the particulate fraction of transfected COS cells.

To elucidate the structural basis for membrane attachment of the alpha subunit of the stimulatory G protein (Gs alpha), mutant Gs alpha cDNAs with deletions of amino acid residues in the amino and/or carboxy termini were transiently expressed in COS-7 cells. The particulate and soluble fractions prepared from these cells were analyzed by immunoblot using peptide specific antibodies to monitor distribution of the expressed proteins. Transfection of mutant forms of Gs alpha with either 26 amino terminal residues deleted (delta 3-28) or with 59 amino terminal residues deleted (delta 1-59) resulted in immunoreactive proteins which localized primarily to the particulate fraction. Similarly, mutants with 10 (delta 385-394), 32 (delta 353-384), or 42 (delta 353-394) amino acid residues deleted from the carboxy terminus also localized to the particulate fraction, as did a mutant form of Gs alpha lacking amino acid residues at both the amino and carboxy termini (delta 3-28)/(delta 353-384). Mutant and wild type forms of Gs alpha demonstrated a similar degree of tightness in their binding to membranes as demonstrated by treatment with 2.5 M NaCl or 6 M urea, but some mutant forms were relatively resistant compared with wild type Gs alpha to solubilization by 15 mM NaOH or 1% sodium cholate. We conclude that: (a) deletion of significant portions of the amino and/or carboxyl terminus of Gs alpha is still compatible with protein expression; (b) deletion of these regions is insufficient to cause cytosolic localization of the expressed protein. The basis of Gs alpha membrane targeting remains to be elucidated.

Stimulation of Xenopus oocyte maturation by inhibition of the G-protein alpha S subunit, a component of the plasma membrane and yolk platelet membranes.

Oocytes of Xenopus laevis undergo maturation when injected with an affinity-purified antibody against the COOH-terminal decapeptide of the alpha subunit of the G-protein Gs, an antibody that inhibits Gs activity. Germinal vesicle breakdown, chromosome condensation, and polar body formation occur, with a time course similar to that for oocytes treated with progesterone. The alpha S antibody-injected oocytes also acquire the ability to be activated by sperm. Coinjection of the catalytic subunit of cAMP-dependent protein kinase, or incubation with cycloheximide, inhibits maturation in response to injection of the alpha S antibody; these experiments show that the alpha S antibody acts at an early point in the pathway leading to oocyte maturation, before formation of maturation promoting factor, and like progesterone, its action requires protein synthesis. Immunogold electron microscopy shows that alpha S is present in the yolk platelet membranes as well as the plasma membrane. These results support the hypothesis that progesterone acts by inhibiting alpha S, and suggest that the target of progesterone could include yolk platelet membranes as well as the plasma membrane.

Oocyte maturation in starfish is mediated by the beta gamma-subunit complex of a G-protein.

The stimulation of meiotic maturation of starfish oocytes by the hormone 1-methyladenine is mimicked by injection of beta gamma subunits of G-proteins from either retina or brain. Conversely, the hormone response is inhibited by injection of the GDP-bound forms of alpha i1 or alpha t subunits, or by injection of phosducin; all of these proteins should bind free beta gamma. alpha-subunit forms with reduced affinity for beta gamma (alpha i1 or alpha t bound to hydrolysis-resistant GTP analogs, or alpha i1-GMPPCP treated with trypsin to remove the amino terminus of the protein) are less effective inhibitors of 1-methyladenine action. These results indicate that the beta gamma subunit of a G-protein mediates 1-methyladenine stimulation of oocyte maturation.

The G protein connection: molecular basis of membrane association.

Two distinct types of lipid modification, myristoylation and isoprenylation, are critical for membrane association of heterotrimeric G proteins. Elucidation of the molecular basis for G protein membrane association has important implications for understanding G protein structure and function, and is relevant to potential therapeutic approaches to AIDS and cancer.

Hispanic ethnicity, race and blood donation in the United States.

The aim of this study was to assess the hypothesis that blood donation rates vary with Hispanic ethnicity (family origin in Spanish-speaking countries) in addition to race in the United States. Lower blood donation rates have been reported among African Americans (AAs) compared with non-Hispanic European Americans (EAs). Adequate published reports on donation rates are not available for Hispanic Americans (HAs). Using data from a 2002 national survey, which included 4923 men and 7600 women aged 15-44 years with complete data, we tested the hypothesis using weighted bivariate and multivariate statistics. Among men aged 25-44 years, the percentage [95% confidence limits (95% CL)] with a history of blood donation since 1985 was similar at ages 25-34 years (46%, 42-49) and 35-44 years (41%, 37-45). It was highest in non-Hispanic EA (49%, 45-52%), intermediate in AA (35%, 30-40%) and lowest in HA (30%, 25-36%) (P < 0.001). Other variables significantly (P < 0.01) associated with history of blood donation in bivariate analyses were nativity (United States/other), education (<12/>or=12 years), poverty (<200%/>or=200% poverty limit) and married (yes/no). Variables that are not significantly associated were age, metropolitan residence (yes/no), receipt of public assistance (yes/no), current labour-force participation (yes/no) and religion raised. Compared with non-Hispanic EA, the adjusted odds ratios were essentially the same for Hispanics 0.66 (95% CL 0.47-0.92) and AAs 0.64 (95% CL 0.49-0.84). Only 34% of women had donated blood, but the association with race/ethnicity was similar. Similar patterns were also seen at ages 15-24 years. HAs and AAs have similar low blood donation rates compared with non-Hispanic EAs. The difference is not explained by sociodemographic variables.

Fluctuating asymmetry of the normal facial skeleton.

The purpose of this study was to produce reliable estimations of fluctuating facial asymmetry in a normal population. Fifty-four computed tomography (CT) facial models of average-looking and symmetrical Chinese subjects with a class I occlusion were used in this study. Eleven midline landmarks and 12 pairs of bilateral landmarks were digitized. The repeatability of the landmark digitization was first evaluated. A Procrustes analysis was then used to measure the fluctuating asymmetry of each CT model, after all of the models had been scaled to the average face size of the study sample. A principal component analysis was finally used to establish the direction of the fluctuating asymmetries. The results showed that there was excellent absolute agreement among the three repeated measurements. The mean fluctuating asymmetry of the average-size face varied at each anthropometric landmark site, ranging from 1.0mm to 2.8mm. At the 95% upper limit, the asymmetries ranged from 2.2mm to 5.7mm. Most of the asymmetry of the midline structures was mediolateral, while the asymmetry of the bilateral landmarks was more equally distributed. These values are for the average face. People with larger faces will have higher values, while subjects with smaller faces will have lower values.

A proline-rich region and nearby cysteine residues target XLalphas to the Golgi complex region.

XLalphas is a splice variant of the heterotrimeric G protein, Galpha(s), found on Golgi membranes in cells with regulated and constitutive secretion. We examined the role of the alternatively spliced amino terminus of XLalphas for Golgi targeting with the use of subcellular fractionation and fluorescence microscopy. XLalphas incorporated [(3)H]palmitate, and mutation of cysteines in a cysteine-rich region inhibited this incorporation and lessened membrane attachment. Deletion of a proline-rich region abolished Golgi localization of XLalphas without changing its membrane attachment. The proline-rich and cysteine-rich regions together were sufficient to target the green fluorescent protein, a cytosolic protein, to Golgi membranes. The membrane attachment and Golgi targeting of the fusion protein required the putative palmitoylation sites, the cysteine residues in the cysteine-rich region. Several peripheral membrane proteins found at the Golgi have proline-rich regions, including a Galpha(i2) splice variant, dynamin II, betaIII spectrin, comitin, and a Golgi SNARE, GS32. Our results suggest that proline-rich regions can be a Golgi-targeting signal for G protein alpha subunits and possibly for other peripheral membrane proteins as well.

Complications following arthroscopic surgery of the hip: a systematic review of 36 761 cases.

AIMS: The number of patients undergoing arthroscopic surgery of the hip has increased significantly during the past decade. It has now become an established technique for the treatment of many intra- and extra-articular conditions affecting the hip. However, it has a steep learning curve and is not without the risk of complications. The purpose of this systematic review was to determine the prevalence of complications during and following this procedure. MATERIALS AND METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used in designing this study. Two reviewers systematically searched the literature for complications related to arthroscopy of the hip. The research question and eligibility criteria were established a priori. Pertinent data were abstracted and analysed. RESULTS: We found 276 relevant studies with a total of 36 761 arthroscopies that met the inclusion criteria. The mean age of the patients was 36.7 years (1.7 to 70) and the mean body mass index was 25.7 kg/m2 (20.2 to 29.2). Femoroacetabular impingement and labral tears were the most common indications for the procedure. The total number of complications was 1222 (3.3%). Nerve injury (0.9%), mainly involving the pudendal and lateral femoral cutaneous nerves, and iatrogenic chondral and labral injury (0.7%), were the two most common complications. There were 58 major complications (0.2%), the most common being intra-abdominal extravasation of fluid, which was found in 13 cases (0.04%). There were three deaths (0.008%). CONCLUSION: Arthroscopic surgery of the hip is a procedure with a relatively low rate of complications, although some may be significant in this young cohort of patients. This study relied on the reported complications only and the results should be interpreted with caution. Cite this article: Bone Joint J 2017;99-B:1577-83.

Crystal structure of the human acyl protein thioesterase I from a single X-ray data set to 1.5 A.

BACKGROUND: Many proteins undergo posttranslational modifications involving covalent attachment of lipid groups. Among them is palmitoylation, a dynamic, reversible process that affects trimeric G proteins and Ras and constitutes a regulatory mechanism for signal transduction pathways. Recently, an acylhydrolase previously identified as lysophospholipase has been shown to function as an acyl protein thioesterase, which catalyzes depalmitoylation of Galpha proteins as well as Ras. Its amino acid sequence suggested that the protein is evolutionarily related to neutral lipases and other thioesterases, but direct structural information was not available. RESULTS: We have solved the crystal structure of the human putative Galpha-regulatory protein acyl thioesterase (hAPT1) with a single data set collected from a crystal containing the wild-type protein. The phases were calculated to 1.8 A resolution based on anomalous scattering from Br(-) ions introduced in the cryoprotectant solution in which the crystal was soaked for 20 s. The model was refined against data extending to a resolution of 1.5 A to an R factor of 18.6%. The enzyme is a member of the ubiquitous alpha/beta hydrolase family, which includes other acylhydrolases such as the palmitoyl protein thioesterase (PPT1). CONCLUSIONS: The human APT1 is closely related to a previously described carboxylesterase from Pseudomonas fluorescens. The active site contains a catalytic triad of Ser-114, His-203, and Asp-169. Like carboxylesterase, hAPT1 appears to be dimeric, although the mutual disposition of molecules in the two dimers differs. Unlike carboxylesterase, the substrate binding pocket and the active site of hAPT1 are occluded by the dimer interface, suggesting that the enzyme must dissociate upon interaction with substrate.

Expression of an amphibian homolog of the Eph family of receptor tyrosine kinases is developmentally regulated.

In order to study the function of tyrosine kinase receptors during Xenopus development, we have isolated Xek (Xenopus Elk-like kinase), a tyrosine kinase receptor, which shows significant homology to rat Elk and chicken cek5, members of the Eph family. Xek exists as a maternally expressed mRNA which decreases in expression at the mid blastula transition and reappears at late neurulation in Xenopus. Xek mRNA is expressed at higher levels in the anterior and dorsal regions of embryonic stages 16, 24 and 37. In adult Xenopus tissues, Xek appears to be ubiquitously expressed with higher expression observed in brain and ovary. In situ hybridization analysis demonstrates localized mRNA expression in the brain, brachial arches, trigeminal facial ganglion, and the retina of the swimming tadpole stage of development. The similarities in sequence and expression pattern suggest that Xek is an amphibian member of the Eph family and may play a role in the development or function of the central nervous system.

Identification of XLerk, an Eph family ligand regulated during mesoderm induction and neurogenesis in Xenopus laevis.

We have isolated and characterized the first Xenopus transmembrane Eph ligand, XLerk (Xenopus Ligand for Eph Receptor Tyrosine Kinases). While this ligand has 72% identity with the closest mammalian family member, Lerk-2, it is the cytoplasmic domain of this molecule that is the most conserved domain with 95% identity. XLerk exists as a maternally expressed mRNA, however, expression of transcripts and protein increase during gastrulation and again in the late swimming tadpole stage. In the adult, XLerk is expressed at low levels in most adult tissues with increased levels observed in the kidney, oocytes, ovary and testis. While low levels of XLerk expression are observed in the adult brain, in situ hybridization analysis demonstrates prominent expression in the developing olfactory system, retina, hindbrain, cranial ganglia, and somites. Furthermore, we have shown that XLerk transcripts are significantly elevated during mesoderm induction caused by activin and FGF, but not during noggin-induced neuralization. These results suggest a role for XLerk in the developing mesenchymal and nervous tissue.

Xmeis1, a protooncogene involved in specifying neural crest cell fate in Xenopus embryos.

Meis1 (Myeloid Ecotropic viral Integration Site 1) is a homeobox gene that was originally isolated as a common site of viral integration in myeloid tumors of the BXH-2 recombinant inbred mice strain. We previously isolated a Xenopus homolog of Meis1 (Xmeis1). Here we show that Xmeis1 may play a significant role in neural crest development. In developing Xenopus embryos, Xmeis1 displays a broad expression pattern, but strong expression is observed in tissue of neural cell fate, such as midbrain, hindbrain, the dorsal portion of the neural tube, and neural crest derived branchial arches. In animal cap explants, overexpression of Xmeis1b, an alternatively spliced form of Xmeis1, induces expression of neural crest marker genes in the absence of mesoderm. Moreover, Xmeis1b induces XGli-3 and XZic3, pre-pattern genes involved at the earliest stages of neural crest development, and like these two genes, can induce ectopic pigmented cell masses when overexpressed in developing embryos. Misexpression of Xmeis1b also induces ectopic expression of neural crest markers along the antero-posterior axis of the neural tube in developing Xenopus embryos. In contrast, Xmeis1a, another splice variant, is much less effective at inducing these effects. These data suggest that Xmeis1b is involved in neural crest cell fate specification during embryogenesis, and can functionally intersect with the Gli/Zic signal transduction pathway.

Circadian Regulation of Sucrose Phosphate Synthase Activity in Tomato by Protein Phosphatase Activity.

Sucrose phosphate synthase (SPS), a key enzyme in sucrose biosynthesis, is regulated by protein phosphorylation and shows a circadian pattern of activity in tomato. SPS is most active in its dephosphorylated state, which normally coincides with daytime. Applying okadaic acid, a potent protein phosphatase inhibitor, prevents SPS activation. More interesting is that a brief treatment with cycloheximide, a cytoplasmic translation inhibitor, also prevents the light activation of SPS without any effect on the amount of SPS protein. Cordycepin, an inhibitor of transcript synthesis and processing, has the same effect. Both of these inhibitors also prevent the activation phase of the circadian rhythm in SPS activity. Conversely, cycloheximide and cordycepin do not prevent the decline in circadian SPS activity that normally occurs at night. These observations indicate that SPS phosphatase activity but not SPS kinase activity is controlled, directly or indirectly, at the level of gene expression. Taken together, these data imply that there is a circadian rhythm controlling the transcription of a protein phosphatase that subsequently dictates the circadian rhythm in SPS activity via effects on this enzyme's phosphorylation state.