The spinal cord and its membranes

The spinal cord is 45 cm long in the adult. In the early fetus, it extends the length of the vertebral canal; differential growth results in its termination at L3 in the newborn. In the adult it terminates, as the conus medullaris, at the disc between L1 and L2, although there is a range from T12 to L3. Inferiorly, the nerve roots form the cauda equina, while the lower end of the cord is attached by the filum terminale, of pia mater, to the coccyx. The dural sac terminates usually at the second segment of the sacrum. The cord receives its arterial supply from the anterior and posterior spinal arteries, which descend from the foramen magnum. They are reinforced serially via the intervertebral foramina from segmental vessels, especially the arteria magna. The three layers of the meninges are the dura mater, arachnoid mater and pia mater. The cerebrospinal fluid is contained within the subarachnoid space. The epidural space contains fat, blood vessels, lymphatics and the nerve roots.     

Acute toxicity of 50 metals to Daphnia magna

Metals are essential for human life and physiological functions but may sometimes cause disorders. Therefore, we conducted acute toxicity testing of 50 metals in Daphnia magna: EC50s of seven elements (Be, Cu, Ag, Cd, Os, Au and Hg) were < 100 µg l^?1; EC50s of 13 elements (Al, Sc, Cr, Co, Ni, Zn, Se, Rb, Y, Rh, Pt, Tl and Pb) were between 100 and 1000 µg l^?1; EC50s of 14 elements (Li, V, Mn, Fe, Ge, As, In, Sn, Sb, Te, Cs, Ba, W and Ir) were between 1,001 and 100,000 µg l^?1; EC50s of six elements (Na, Mg, K, Ca, Sr and Mo) were > 100,000 µg l^?1; and. 7 elements (Ti, Zr, Bi, Nb, Hf, Re and Ta) did not show EC50 at the upper limit of respective aqueous solubility, and EC50s were not obtained. Ga, Ru and Pd adhered to the body of D. magna and physically retarded the movement of D. magna. These metals formed hydroxides after adjusting the pH. Therefore, here, we distinguished this physical effect from the physiological toxic effect. The acute toxicity results of 40 elements obtained in this study were not correlated with electronegativity. Similarly, the acute toxicity results of metals including the rare metals were also not correlated with first ionization energy, atomic weight, atomic number, covalent radius, atomic radius or ionic radius. Copyright © 2014 John Wiley & Sons, Ltd.     

Torkildsen shunt as a salvage procedure for an infant with post-hemorrhagic hydrocephalus

IntroductionTorkildsen operation is a ventriculo-cisternal shunt that diverts the cerebrospinal fluid flow from one of the lateral ventricles, via a ventricular catheter, to the cisterna magna of the posterior fossa. It is the first described operation of CSF diversion for the treatment of hydrocephalus [1] (Scarff, 1963).Presentation of caseWe present the case of a premature infant who presented with post hemorrhagic hydrocephalus who underwent several failed CSF diversion surgeries before Torkildsen shunt procedure. The patient overcame the irregularities of CSF circulation that were observed before the operation and his post-operative course was uneventful, in terms of CSF –related complications.DiscussionWe summarize the historical data and the technical aspects of the procedure, and we present a brief literature review of the indications and limitations associated with it.ConclusionTorkildsen shunt can be effective in selected patients with hydrocephalus even in the modern era of computed tomography and magnetic resonance imaging. the procedure enables one to avoid a standard ventriculoperitoneal shunt, especially in cases it is not technically feasible.     

Metabolomic method to detect a metabolite corona on amino-functionalized polystyrene nanoparticles

Abstract

Protein coronas on nanoparticles (NPs) affect their physicochemical properties, cellular uptake, and toxicity, and have been described extensively. To date, studies of the occurrence of small molecule (metabolite) coronas are limited. We sought to determine whether a metabolite corona forms on NPs, using high-sensitivity metabolomics combined with a model system for freshwater ecotoxicology (Daphnia magna feeding on Chlorella vulgaris). Using amino-functionalized polystyrene NPs (NH₂-pNPs), we showed the impact of this material on Daphnia feeding to provide a rationale for the detailed molecular investigations. We then employed a targeted LC-MS/MS approach for sodium dodecyl sulfate (SDS) as an analog to signaling molecules known to occur in our freshwater model system and optimized a corona extraction method for this representative metabolite. Next, we performed an untargeted discovery-based metabolomics study – using high-sensitivity nanoelectrospray direct infusion mass spectrometry (DIMS) – to enable an unbiased assessment of the metabolite corona of NH₂-pNPs in the freshwater model system. Our results demonstrate that SDS was successfully recovered from NH₂-pNPs, confirming that the extraction protocol was fit-for-purpose. Untargeted DIMS metabolomics reproducibly detected 100?s of small molecule peaks extracted from NH₂-pNPs exposed to conditioned media from the D. magna–C. vulgaris model system. Attempts to annotate these extracted metabolites, including by using van Krevelen and Kendrick Mass Defect plots, indicate a diverse range of metabolites that were not clustered into any particular class. Overall we demonstrate the existence of an ecologically relevant metabolite corona on the surface of NPs through application of a high-sensitivity, untargeted mass spectrometry metabolomics workflow.     

结膜吸吮线虫实验室感染大绕眼果蝇

在安徽黄山地区捕捉有绕眼习性的果蝇,将结膜吸吮线虫初产蚴混于果汁中,实验室喂饲感染果蝇,常温饲养20 d后,检查果蝇的感染情况。结果显示,大绕眼果蝇（Amiota magna）和冈田绕眼果蝇（A. okadai）的阳性率分别为30%（30/100）和21.6%（55/255）,两者间的差异无统计学意义（χ²=0.058 4, P>0.05）。将采自大绕眼果蝇的结膜吸吮线虫感染期幼虫接种家兔,35 d后在兔结膜囊内检获结膜吸吮线虫成虫及其初产蚴,表明在实验室条件下,结膜吸吮线虫可感染大绕眼果蝇。     

胎儿小脑延髓池间隔的超声检测及其临床意义

目的 探讨不同孕龄胎儿小脑延髓池间隔(CMS)的正常声像图表现及正常值,并评估CMS的临床意义.方法 前瞻性选择416例不同孕周正常胎儿,采用二维超声对CMS的长径和宽径进行检测,并对其测值与孕周进行回归分析.回顾性总结我院6年间25例CMS消失的病例和12例CMS增大胎儿的临床资料.结果 ①胎儿CMS的长径和宽径在14～22孕周随着孕周的增加而增大,在23～36孕周变化不大,在37孕周后有变小趋势,与菱脑胚胎发育过程一致.②CMS消失常见于Dandy-Walker畸形、全前脑、严重脑积水、神经管缺陷、菱脑融合症、Arnold-Chiari畸形;CMS增大可见于小脑延髓池生理性增大.结论 CMS是菱脑发育正常的标志之一.CMS增大和消失与多种胎儿中枢神经系统畸形有关,尤其是后颅窝畸形.

Abstract：

Objective To establish normative data for the fetal cisterna magna septa (CMS) at various gestational age,and to evaluate its clinical significance.Methods A total of consecutive fetal between 14 and 40 gestational week(GW) were included in this prospective study.The length and width of CMS were measured by two-dimensional ultrasonography.Regression analysis was used to study the relationship between the width and length of the fetal cisterna magna septa and gestational age.Twenty-five case of fetuses with the absence of CMS and 12 case of fetuses with the enlargement of CMS were retrospectively analyzed in the past six years in our hospital.Results ①The fetal CMS length and width increased gradually between 14 and 22 GW,then plateaued between 23 GW and 36 GW,and decreased after 37 GW.This ultrasonographic pattern was in agreement with normal development of rhombencephalon.②The absence of CMS in the fetuses were common in Dandy-Walker syndrome,holoprosencephaly,severe hydrocephalus,neural tube defects,rhombencephalon synapsis and Arnold-Chiari malformation.The enlargement of CMS in the fetuses may be shown in physiologic enlargement of posterior fossa.ConclusionsCMS is a potential new marker for normal development of rhombencephalon.The enlargement and absence of CMS are related to various malformations of central neural system,especially in the abnormalities of posterior fossa.     

Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna

Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high‐throughput methods for detecting sublethal effects. We have evaluated an automated infra‐red (IR) light‐based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K₂Cr₂O₇ at 15, 20 and 25 °C and 2,4‐dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K₂Cr₂O₇ whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12–18 h. A similar biphasic pattern was observed after 2,4‐dichlorophenol exposure at 20 °C. EC₅₀ values for 2,4‐dichlorophenol and K₂Cr₂O₇ determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC₅₀ of 0.03–0.07 mg l^–1 h^–1. EC₅₀ values determined after 48 h were comparable or lower than EC₅₀ values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high‐throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of subcutaneous suture line and surgical technique on wound infection after saphenectomy in coronary artery bypass grafting: a prospective randomised study

Objective. The aim of the study was to evaluate the impact of an additional subcutaneous suture line on the incidence of postoperative (p.o.) infection at the vena saphena magna harvesting site (VSMHS) after coronary artery bypass grafting (CABG). Methods. Two hundred and forty three patients undergoing CABG were included. Patients in Group A (n?=?119) all operated by one physical assistant (PA) were prospectively randomised into Group A1 (n?=?59) receiving intracutaneous closure suture alone whereas 60 patients (Group A2) received an additional subcutaneous suture line. Group B (n?=?120), operated by surgical residents, served as control population. All patients were due to follow-up at six weeks p.o. Results. Subcutaneous suture did not impact the p.o. infection rate (A2 vs. A1; 4/60 vs. 2/59, n.s.). A significant lower p.o. infection rate was observed in Group A vs. Group B (6/119 (5%) vs. 15/120 (13%) p?<?0.05). Conclusion. Subcutaneous suture did not impact the p.o. infection rate at VSMHS. The infection rate observed in patients operated by an experienced PA was significantly lower than in patients operated by various surgical residents.     

Acute toxicity of inorganic selenium to Daphnia magna (Straus) and the effect of sub-acute exposure upon growth and reproduction

The acute toxicities of sodium selenite (Na₂SeO₃) and sodium selenate (Na₂SeO₄) to Daphnia magna were determined in defined culture at 22°C. For adults, the 48-h LC₅₀ values were 0.68 ppm selenium as selenite and 0.75 ppm selenium as selenate. Juveniles were more sensitive, with a 48-h LC₅₀ of 0.55 ppm selenium as selenate. Eggs and embryos were found to be much less sensitive, with a 72-h LC₅₀ of 1.4 ppm selenium as selenate.

Sub-acute exposure of D. magna to sodium selenate caused suppression of growth over instars 1–5 and reduced egg production in instar 9 when adults were exposed to test solutions from instar 6 onwards. These sublethal effects were found at concentrations in the range proposed as suitable for the use of selenium in the amelioration of mercury contamination.