A unique subpopulation of Tbr1-expressing deep layer neurons in the developing cerebral cortex

Cells of the subplate (SP) and deep cortical plate (CP) are among the pioneer neurons of the developing cerebral cortex, an important group of early-born cells that impact cortical organization and function. Similarities between pioneer neurons in different cortical positions and heterogeneities in pioneer cells in the same cortical location, however, have made it difficult to appreciate the characteristics and functions of particular sets of these cells. Here, we provide a tool to illuminate a unique subset of SP and deep CP neurons: expression of a Tbrain-1 (Tbr1)-driven transgene. Transgene-expressing cells were consistently positive for neuronal but not glial markers, were born early in corticogenesis, representing just a subset of SP and deep CP neurons, were morphologically complex during the formation of the cortex, and were maintained into maturity. This analysis reveals a novel group of pioneer neurons and demonstrates unrecognized diversity within this cortical population. In the future, this information will help to uncover the roles of discrete pioneer populations in cortical development.     

Psychologic trauma, posttraumatic stress disorder, and dermatology

Psychologic trauma refers to events (such as sexual assault, major earthquake, or plane crashes) that overwhelm an individual's capacity to cope. Psychologic trauma can result in chronic and recurring dermatologic symptoms that persist after the trauma subsides. Examples are cutaneous sensory flashbacks (which may be fragments of the sensory component of the traumatic experience), autonomic hyperarousal (with symptoms such as profuse sweating or flare-up of an underlying stress-reactive dermatosis), conversion symptoms (such as numbness, pain, or other medically unexplained cutaneous symptoms), and cutaneous self-injury (manifesting in many forms, including trichotillomania, dermatitis artefacta, and neurotic excoriations--tension-reducing behaviors in patients who have posttraumatic stress disorder).     

Stabilit?t der Osteosynthese bei Gelenkwalzenfrakturen in Klinik und biomechanischer Simulation

BACKGROUND: Fractures of the condylar head are traditionally managed by closed techniques, despite a considerable rate of dysfunctional problems. PDS pin osteosynthesis (presented by Rasse 1992) via a preauricular approach failed to become established as a standard procedure due to a lack of stability. Alternatively, mini- or microplating, as performed in our patients (101 condylar head fractures between 1993 and 2000), showed high-grade limitations of translatory movements in about 30% due to scarification after loosening of osteosynthesis materials. The aim of this study was to establish an efficient procedure for achieving a functionally stable and atraumatic osteosynthesis. METHODS: For the definition of a suitable procedure, models of the mandible (standardized fractures, types A, B, and C) were osteosynthesized (six samples for each type of fracture and type of screw), each with three PDS pins, 2.0 mm resorbable, 2.0 cortical, 1.7 and 1.2 mm small fragment screws, and exposed to increasing loads in centric (0-20-35 mm opening) and eccentric (35 mm opening) condylar positions. A computerized biomechanical test stand allowed a dynamic simulation of chewing forces (16 hydraulic drives). The resulting fracture gaps were measured without contact by a motion capture system. RESULTS: Within physiological limits, only 1.7 small fragment and 2.0 mm cortical screws were able to bear occlusal loadings up to 200 N (1.2 mm small fragment screws up to 150 N, resorbable 2.0 mm screws up to 100 N, and PDS-pins up to 50 N). In a pullout experiment (condylar spongious bone of young pigs, aged 4-6 months), 1.7 mm small fragment screws showed superior retention. A consecutively developed small fragment screw-system has been applied clinically in 74 condylar head fractures (58 patients). After removal of osteosynthesis material, 41 of 49 TM joints have so far shown complete restitution. CONCLUSIONS: The newly developed osteosynthesis system using a retroauricular approach based on 1.7 mm small fragment screws makes maxillomandibular immobilization unnecessary. The extra-articular position of the screw heads prevents scar-induced articular limitations. Preexisting degenerative alterations of the TMJ soft tissues, however, will affect functional results adversely.     

Physiological control of Xunc18 expression in neuroendocrine melanotrope cells of Xenopus laevis

In mammals, the brain-specific protein munc18-1 regulates synaptic vesicle exocytosis at the synaptic junction, in a step before vesicle fusion. We hypothesize that the rate of biosynthesis of munc18-1 messenger RNA (mRNA) and the amount of munc18-1 present in neurons and neuroendocrine cells are related to the physiologically controlled state of activity. To test this hypothesis, the homolog of munc18-1 in the clawed toad Xenopus laevis, xunc18, was studied in the brain and in the neuroendocrine melanotrope cells in the intermediate lobe of the pituitary gland, at both the mRNA and the protein level. In toads adapted to a black background, the melanotropes release the peptide alpha-melanophore-stimulating hormone (alpha-MSH), which induces darkening of the skin, whereas in animals adapted to a white background the cells hardly release but store alpha-MSH, making the animal's skin look pale. The intermediate pituitary lobe of black-adapted animals revealed a strong hybridization reaction with the xunc18 mRNA probe, whereas a much weaker hybridization was observed in the intermediate lobe of white-adapted animals (optical density black: 3.4 +/- 0.2 vs. white: 0.8 +/- 0.1; P < 0.02). Immunocytochemically, Xenopus munc18-like protein has been detected throughout the brain, in identified neuronal perikarya as well as in axon tracts. Western blot analysis and immunocytochemistry further demonstrated the presence of xunc18 in the neural, intermediate and distal lobe of the pituitary gland. Xunc18 protein was furthermore determined in immunoblots of homogenates of melanotropes dissociated from the pituitary gland. In melanotropes of toads adapted to a black background, the integrated optical density of the xunc18 immunosignal was 2.7 +/- 0.5 times higher than in cells of white-adapted toads (P < 0.0001). It is concluded that, in Xenopus melanotrope cells, the amounts of both xunc18 mRNA and xunc18 protein are up-regulated in conjunction with the induction of exocytosis of alpha-MSH as a result of a physiological stimulation (environmental light condition). We propose that xunc18 is involved in physiologically controlled exocytotic secretion of neuroendocrine messengers.     

The psychobiology and psychopharmacology of PTSD

This paper reviews the currently available knowledge about the psychobiology and psychopharmacology of post-traumatic stress disorder (PTSD). It also reviews the various studies that have elucidated changes in brain function and structure in PTSD populations, including position emission tomography (PET), single photon emission computed tomography (SPECT), and event-related potential (ERP) studies. It then reviews the literature on catecholamine and hypothalamic-pituitary-adrenal (HPA) axis abnormalities in PTSD, and finally reviews the literature available on the psychopharmacology of PTSD. It discusses how the pathophysiology of PTSD determines the nature of psychopharmacological interventions. Psychopharmacological interventions in PTSD are largely limited to good studies on the effects of the selective serotonin reuptake inhibitors (SSRIs). In order to effectively intervene in PTSD, studies of other psychopharmacological agents are necessary, specifically of agents which affect limbic activation, decreased frontal lobe functioning, altered HPA activity, and other biological features of PTSD. Copyright 2001 John Wiley & Sons, Ltd.     

Chronic Arsenic Poisoning From Burning High-Arsenic-Containing Coal In Guizhou, China

Optimization of a previously disclosed sorbitol dehydrogenase inhibitor (SDI, II) for potency and duration of action was achieved by replacing the metabolically labile N,N-dimethylsulfamoyl group with a variety of heterocycles. Specifically, this effort led to a series of novel, in vitro potent SDIs with longer serum half-lives and acceptable in vivo activity in acutely diabetic rats (e.g., 62, 67, and 69). However, the desired in vivo potency in chronically diabetic rats, ED90 less than or equal to 5 mg/kg/day, was achieved only through further modification of the piperazine linker. Several members of this family, including 86, showed better than the targeted potency with ED90 values of 1-2 mg/kg/day. Compound 86 was further profiled and found to be a selective inhibitor of sorbitol dehydrogenase, with excellent pharmacodynamic/pharmacokinetic properties, demonstrating normalization of sciatic nerve fructose in a chronically diabetic rat model for approximately 17 h, when administered orally at a single dose of 2 mg/kg/day.     

The effect of Ramadan on maternal nutrition and composition of breast milk

BACKGROUND: There are many advantages of breast milk for infants. Many factors can affect the volume and composition of breast milk. One of them is the maternal diet. The objective of this study is to determine the effect of Ramadan fasting on maternal nutrition and breast milk composition. METHODS: A total of 21 breast-feeding mothers aged between 17 and 38 years who fasted during Ramadan month and volunteered to give milk samples were surveyed. The ages of the infants were between 2 and 5 months. The study was performed during Ramadan and 2 weeks after the end of Ramadan. RESULTS: The results showed that during Ramadan, zinc, magnesium and potassium levels in breast milk decreased significantly (P<0.05). The mother's weight increased approximately 1 kg after Ramadan. Changes in body mass index of the mother were not statistically significant. A significant decrease in vitamin A intake was observed after Ramadan (P < 0.05). During Ramadan, energy and most nutrient intakes except protein and vitamins A and C were found below daily recommended dietary allowances necessary for lactating women. CONCLUSIONS: Ramadan fasting had no significant effect on the macronutrient composition of the breast milk and consequently the growth of the infants. There were significant differences in some of the micronutrients such as zinc, magnesium and potassium. The nutritional status of lactating women was affected by Ramadan fasting. All of the nutrient intakes (except vitamins A, E and C) decreased during Ramadan. For these reasons, it would seem prudent to excuse lactating women from fasting during Ramadan.     

The Prevalence of Cryptosporidium spp. in Children,Taiz District,Yemen

Background

This is the first work done on cryptosporidiosis among the children in Taiz, Yemen.

Methods

A number of 712 samples were collected from children of different ages (ranging from 1 month to 12 years) from Dec 2006 to Aug 2007. The collected samples were examined by Sheather''s sugar floatation and Modified Ziehl- Neelsen stain as well as ELISA methods. The test results were statistically analyzed by SPSS software.

Results

The overall positive percentage was 43.7%. The higher incidence (36.2%) was occurred in males while the lowest incidence (32.7%) was observed in females (r=0.876; P=0.001). The correlation between infected cases and the type of drinking water was r =0.121. Among the cases examined by ELISA (92 cases), 26.1% were infected. The correlation between seropositivity and gender was r=0.652 (P=0.031).

Conclusion

Cryptosporidium spp. is a significant pathogen among children at Taiz. Fresh water supplies, education, eating habits and domestic animals are considered the main sources for transmission of cryptosporidiosis.     

皮质类固醇治疗外伤性视神经病变的四天关键时期(英文)

目的:评估静脉注射甲基强的松龙(IVMP)对外伤性视神经病变患者的疗效。方法:回顾性分析2000-01至2007-06我院收治的16例外伤性视神经病变(TON)患者的临床资料。1g甲基强的松龙分3d静脉应用,然后口服泼尼松龙11d,并逐渐减量。记录从损伤开始到治疗开始的时间。视力变化是本研究结果的主要功能评价指标。在入院时,治疗后1,2,3d;1wk和1mo时,分别记录最佳矫正视力(BCVA)。结果:共有16例患者纳入本研究,平均年龄为30岁,其中男性14例、女性2例。引起TON的主要原因有摩托车事故(占69%),打架斗殴(占19%)和体育运动(占12%)。所有患者都表现有相对传入性瞳孔障碍。在损伤后4d内开始静脉注射甲基强的松龙,采用Snellen视力表检查视力,绝大部分(56%)患者视力提高超过3行或大于等于0.5(6/12)。在损伤后5d以上才开始用类固醇治疗,视力则没有任何进步。结论:治疗TON,静脉注射中等到大剂量甲基强的松龙仍将起到重要作用。静脉注射甲基强的松龙治疗TON可能存在伤后4d的关键时期,超过了这个时期,该治疗可能就毫无效果。但还需要有更多的研究来为我们提供有明显统计学意义的数据。