Characterization of human DAAO variants potentially related to an increased risk of schizophrenia

Considering the key role of d-serine in N-methyl-d-aspartate receptor-mediated neurotransmission, it is highly relevant to define the role that enzymes play in d-serine synthesis and degradation. In particular, the details of regulation of the d-serine catabolic human enzyme d-amino acid oxidase (hDAAO) are unknown although different lines of evidence have shown it to be involved in schizophrenia susceptibility. Here we investigated the effect of three single nucleotide polymorphisms and known mutations in hDAAO, i.e., D31H, R279A, and G331V. A very low amount of soluble G331V hDAAO is produced in E. coli cells: the recombinant variant enzyme is fully active. Human U87 glioblastoma cells transiently transfected for G331V hDAAO show a low viability, a significant amount of protein aggregates, and augmented apoptosis. The recombinant D31H and R279A hDAAO variants do not show alterations in tertiary and quaternary structures, thermal stability, binding affinity for inhibitors, and the modulator pLG72, whereas the kinetic efficiency and the affinity for d-serine and for FAD were higher than for the wild-type enzyme. While these effects for the substitution at position 31 cannot be structurally explained, the R279A mutation might affect the hDAAO FAD-binding affinity by altering the “structurally ambivalent” peptide V47–L51. In agreement with the observed increased activity, expression of D31H and R279A hDAAO variants in U87 cells produces a higher decrease in cellular d/(d + l) serine ratio than the wild-type counterpart. In vivo, these substitutions could affect cellular d-serine concentration and its release at synapsis and thus might be relevant for schizophrenia susceptibility.     

Inflammatory cytokines and malnutrition as related to risk for cardiovascular disease in hemodialysis patients

Malnutrition and inflammation are associated with end-stage renal disease (ESRD). Interleukin (IL)-6 and tumor necrosis factor alpha (TNF-alpha) powerfully predict death from cardiovascular disease. The aim of our study was to establish an association between markers of inflammation and parameters of malnutrition in patients on hemodialysis. The study population consisted of 42 hemodialysis patients with different parameters of malnutrition. Blood samples were taken after an overnight fast, and plasma lipid profiles (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides) were measured by using conventional enzymatic methods. Serum urea and creatinine levels were also measured by routine procedures. Plasma high-sensitivity C-reactive protein level (hs-CRP), TNF-alpha, and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). Standard Doppler echo examinations were used to determine plaque on carotid arteries, and end-diastolic diameter (EDD) and ejection fraction (EF) were measured by echocardiography. Malnourished patients exhibited significantly greater evidence of cardiovascular disease and carotid plaques. Factor (principal component) analysis indicated 6 latent factors with 67.5% of the variance explained within all investigated parameters. Cluster analysis was used to distinguish the inflammatory markers and the nutritional markers from other parameters and to visualize similarities between variables. In summary, this cross-sectional study in hemodialysis patients found a high prevalence of malnutrition, inflammation, carotid plaques, and cardiovascular disease. Malnourished dialysis patients are more often found with cardiovascular disease and carotid plaques. In addition, these patients have higher levels of inflammatory cytokines, which may partly explain the elevated risk for atherosclerotic vascular disease.     

Another smoking hazard: raised serum IgE concentration and increased risk of occupational allergy.

Individual smoking histories of a general population sample and of two groups of workers exposed to occupational allergens were related to serum IgE concentrations and results of radioallergosorbent and prick tests in the workers. The geometric mean IgE concentration was higher in smokers than in non-smokers. The distribution of serum IgE values in the two groups showed an apparent difference, with a bimodal appearance in the smokers. Evidence of sensitisation against occupational allergens was more common in workers who smoked. The adjuvant effect of smoking on IgE antibody production might be due to damage to airways mucosa and supports the mucosal theory of atopy.     

Perinatal development of laryngeal function

The resistance of the upper airway is strongly influenced by the action of opposing sets of laryngeal muscles. Expiratory airflow may be retarded by active adduction of the arytenoid cartilages or by a reduction in the activity of abductor muscles. In developing sheep the adductor muscles appear to represent the principal means by which lung recoil is opposed. This mechanism, which is most pronounced during non-rapid-eye-movement sleep, is regulated by afferent traffic from the lungs. In fetal sheep the laryngeal muscles are also influenced by breathing movements and sleep states. The adductor muscles are normally tonically active during non-rapid-eye-movement sleep when rhythmical breathing movements are absent. It is possible that this activity is at least partially responsible for elevated tracheal pressures and depressed flow of tracheal fluid during fetal apnea. This hypothesis has been tested by observing the effects of fetal paralysis and recurrent laryngeal nerve section. These experiments suggest that in the fetus near term the larynx makes a major contribution to upper airway resistance and hence to the maintenance of pulmonary expansion which has been shown to influence lung development.     

The future of antigen-specific immunotherapy of allergy

More than 25% of the population in industrialized countries suffers from immunoglobulin-E-mediated allergies. The antigen-specific immunotherapy that is in use at present involves the administration of allergen extracts to patients with the aim to cure allergic symptoms. However, the risk of therapy-induced side effects limits its broad application. Recent work indicates that the epitope complexity of natural allergen extracts can be recreated using recombinant allergens, and hypoallergenic derivatives of these can be engineered to increase treatment safety. It is proposed that these modified molecules will improve the current practice of specific immunotherapy and form a basis for prophylactic vaccination.     

CagA-positive Helicobacter pylori infection may increase the risk of food allergy development.

The aim of this study was to test whether patients with symptomatic food allergy and significant levels of immunoglobulin E (IgE) to alimentary antigens were more likely infected by H. pylori, especially by strains expressing the CagA protein, with respect to controls. A group of 38 patients with symptomatic food allergy and 53 age-matched controls were examined serologically for H. pylori infectious status, and for CagA seropositivity. IgE to alimentary allergens were measured by a commercial kit. The prevalence of H. pylori infection in patients with food allergy and controls was similar (42.1%, and 48.3%, respectively). However, anti-CagA antibodies in H. pylori-infected persons were detected in 62.5% of patients with food allergy, and 28% of controls (P = 0.030, odds ratio = 4.29). The mean level of IgE to the most common alimentary antigens in serum samples from infected patients with anti-CagA antibodies was significantly higher than in CagA-negative infected patients: 3.28 kU/L (SD 3.93), vs. 1.99 kU/L (SD 1.53), P = 0.002, 95% confidence interval = 0.61 to 2.53). Infection by CagA-positive H. pylori increases the risk of developing food allergy.     

Virally delivered cytokines alter the immune response to future lung infections

Respiratory syncytial virus (RSV) is an important cause of infant morbidity and mortality worldwide and is increasingly recognized to have a role in the development and exacerbation of chronic lung diseases. There is no effective vaccine, and we reasoned that it might be possible to skew the immune system towards beneficial nonpathogenic responses by selectively priming protective T-cell subsets. We therefore tested recombinant RSV (rRSV) candidates expressing prototypic murine Th1 (gamma interferon [IFN-γ]) or Th2 (interleukin-4 [IL-4]) cytokines, with detailed monitoring of responses to subsequent infections with RSV or (as a control) influenza A virus. Although priming with either recombinant vector reduced viral load during RSV challenge, enhanced weight loss and enhanced pulmonary influx of RSV-specific CD8⁺ T cells were observed after challenge in mice primed with rRSV/IFN-γ. By contrast, rRSV/IL-4-primed mice were protected against weight loss during secondary challenge but showed airway eosinophilia. When rRSV/IL-4-primed mice were challenged with influenza virus, weight loss was attenuated but was again accompanied by marked airway eosinophilia. Thus, immunization directed toward enhancement of Th1 responses reduces viral load but is not necessarily protective against disease. Counter to expectation, Th2-biased responses were more beneficial but also influenced the pathological effects of heterologous viral challenge.     

Activation-dependent adsorption of cytokines and toxins related to liver failure to carbon beads

In the course of severe pathological conditions, such as acute liver failure and sepsis, toxic metabolites and mediators of inflammation are released into the patient's circulation. One option for the supportive treatment of these conditions is plasmapheresis, in which plasma, after being separated from the cellular components of the blood, is cleansed by adsorption of harmful molecules on polymers or activated carbon. In this work, the adsorption characteristics of activated carbon beads with levels of activation ranging from 0 to 86% were assessed for both hydrophobic compounds accumulating in liver failure (bilirubin, cholic acid, phenol and tryptophan) and cytokines (tumor necrosis factor α and interleukin-6). Progressive activation resulted in significant gradual reduction of both bulk density and mean particle size, in an increase in the specific surface area, and to changes in pore size distribution with progressive broadening of micropores. These structural changes went hand in hand with enhanced adsorption of small adsorbates, such as IL-6 and cholic acid and, to a lesser extent, also of large molecules, such as TNF-α.     

Perinatal development of mammillotegmental connections in rats

Development of direct axonal connections of the hypothalamic mammillary bodies with ventral and dorsal tegmental nuclei of Gudden was studied on fixed rat brains from day 14 of embryonic development until day 10 of postnatal development using the method of diffusion of the lipophilic fluorescent carbocyanine tracer 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate along the neuronal membranes. The tracer was inserted into the mammillary bodies or into the tegmentum and after incubation in a fixative fluorescent nerve cells and nerve fibers were visualized in the brain tissue. The mammillotegmental tract was found to start developing earlier than other conducting systems of the mammillary bodies. On days 14-15 of embryonic development, it was visualized as a bundle of axons running from the mammillary bodies caudally to the midbrain. A group of neurons in the midbrain tegmentum and their axons going to the mammillary bodies via the mammillary peduncle were first visualized on day 19 of embryonic development. The mammillotegmental tract and mammillary peduncle developed progressively from the moment of birth. Ventral and dorsal tegmental nuclei were formed in the midbrain by day 10 of the postnatal development. Thus, the formation of reciprocal connections of the mammillary bodies with midbrain tegmental nuclei was first described during perinatal development in rats.     

Perinatal development of mammillotegmental connections in rats

Development of direct axonal connections of the hypothalamic mammillary bodies with ventral and dorsal tegmental nuclei of Gudden was studied on fixed rat brains from day 14 of embryonic development until day 10 of postnatal development using the method of diffusion of the lipophilic fluorescent carbocyanine tracer 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate along the neuronal membranes. The tracer was inserted into the mammillary bodies or into the tegmentum and, after incubation in a fixative, fluorescent nerve cells and nerve fibers were visualized in the brain tissue. The mammillotegmental tract was found to start developing earlier than other projection systems of the mammillary bodies. On days 14–15 of embryonic development, it was visualized as a bundle of axons running from the mammillary bodies caudally to the midbrain. A group of neurons in the midbrain tegmentum and their axons going to the mammillary bodies via the mammillary peduncle were first visualized on day 19 of embryonic development. The mammillotegmental tract and mammillary peduncle developed progressively from the moment of birth. Ventral and dorsal tegmental nuclei were formed in the midbrain by day 10 of the postnatal development. Thus, the formation of reciprocal connections of the mammillary bodies with midbrain tegmental nuclei was first described during perinatal development in rats.     

IL-17 and related cytokines involved in the pathology and immunotherapy of multiple sclerosis: Current and future developments

Multiple sclerosis (MS), an autoimmune neurological disorder, is driven by self-reactive T helper (Th) cells. Research on the role of Th17 lymphocytes in MS pathogenesis has made significant progress in identifying various immunological as well as environmental factors that induce the differentiation and expansion of these cells, different subsets of Th17 cells with varying degrees of pathogenicity, and the role of the secreted effector cytokines. While approved therapies for MS offer significant benefit to patients, there remain unmet needs. Ongoing clinical trials aim to translate the advanced knowledge of Th17 cytokines to improved therapies. This review discusses the current status and future developments of research into the role of Th17 and related cytokines in MS pathogenesis and therapy.     

Perinatal development of endothelial nitric oxide synthase-deficient mice

The purpose of this study was to evaluate the influence of endothelial nitric oxide synthase (eNOS) deficiency on fetal growth, perinatal survival, and limb development in a mouse model with a targeted mutagenesis of the Nos3 gene. Wild-type (Nos3+/+) and eNOS-deficient fetuses (Nos3-/-) were evaluated on Gestational Day (E)15 and E17, and newborn pups were observed on Day 1 of life (D1). The average term duration of pregnancy was 19 days. For the evaluation of postnatal development, a breeding scheme consisting of Nos3+/- x Nos3+/- and Nos3-/- x Nos3-/- mice was established, and offspring were observed for 3 wk. Southern blotting was used for genotyping. No significant differences in fetal weight, crown-rump lengths (CRL), and placental weight were seen between Nos3+/+ and Nos3-/- fetuses on E15. By E17, Nos3-/- fetuses showed significantly reduced fetal weights, CRL, and placental weights. This difference in body weight was also seen throughout the whole postnatal period. In pregnancies of Nos3-/- females, the average number of pups alive on D1 was significantly decreased compared to either E15 or E17. Placental histology revealed no abnormalities. On E15, E17, and D1, Nos3(-/-) fetuses demonstrated focal acute hemorrhages in the distal limbs in 0%, 2.6%, and 5.7%, respectively, of all mutant mice studied on the respective days. Bone measurements showed significantly shorter bones in the peripheral digits of hindpaws of Nos3-/- newborns. We conclude mice deficient for eNOS show characteristically abnormal prenatal and postnatal development including fetal growth restriction, reduced survival, and an increased rate of limb abnormalities. The development of this characteristic phenotype of eNOS-deficient mice dates back to the prenatal development during the late third trimester of pregnancy.     

婴儿早期不同程度过敏风险高危因素大样本调查

目的通过大样本调查1～3月龄婴儿过敏风险,探讨影响婴儿过敏风险的高危因素。方法随机抽取我院2 188名健康查体的1～3月龄婴儿进行过敏风险程度评估,并对影响婴儿过敏风险程度的部分因素以及婴儿湿疹患病情况进行分析。结果本研究共发放问卷2 188份,全部回收,共剔除无效问卷101份,获得有效问卷2 087份,问卷有效率达95.38%。本研究中婴儿湿疹发病率为49.11%(1 025/2 087),且不同过敏风险婴儿湿疹的发生率不同(均P0.05)。生产方式、喂养方式、父母过敏性疾病史、孕期服用叶酸和孕期烟草烟雾暴露这5个因素与过敏风险关系显著(均P0.05)。性别、胎次、母亲学历、孕周、婴儿洗澡频率、房间通风频率、出生季节、1～3月龄母乳期回避海鲜间差异无统计学意义(均P0.05)。Logistic回归分析显示父母有过敏性疾病史、剖宫产、配方奶和部分人乳喂养、孕期服用叶酸、孕期烟草烟雾暴露为婴儿过敏性疾病发生的危险因素,OR值均1。结论婴儿期是过敏的易感时期,需要通过多种途径对婴儿进行过敏预防,早期过敏风险评估对降低婴儿过敏发生率具有重大意义。     

Successful adult willow grouse are exposed to increased harvest risk

Age and sex ratios in bag records are frequently used as indices of population composition for harvested populations. However, vulnerability to harvest may differ by age and sex thereby producing bias in population estimates. We assessed whether age and sex affected vulnerability to harvest for willow grouse (Lagopus lagopus) where adult density and brood size were known in the harvested populations. We collected bag records during 2 days of controlled hunting in 4 areas in 2 years (2007 and 2008) in Jämtland county, Sweden. We found that vulnerability to harvest was different for chicks and adults, but not between male and female adults. Hunters encountered broods at a higher rate than single birds compared to personnel conducting pre-harvest counts along line transects. Furthermore, the probability of shooting a grouse was higher in encounters of broods than individual grouse. Proportionally, we calculated about a 50% probability of a hunter shooting either a chick or an adult independent of encountering a single bird or broods of 2–10 grouse. Increasing adult density also increased the vulnerability to harvest for adults relative to chicks, independent of the chick to adult ratio in the pre-harvest population. The different vulnerability of adults and chicks to harvest observed in this study will dampen variation in age classes in bag records compared to the population, and we caution against extrapolation of age ratios in bag records to harvested populations. © 2012 The Wildlife Society.