Quantitative imaging of Plasmodium sporozoites in the mammalian host

Malaria, the disease caused by Plasmodium, kills more than 1 million people annually. Little is known of the pre-erythrocytic phase of the parasite life cycle, i.e., after the sporozoite stage is inoculated in the dermis by a mosquito and before the erythrocyte-infecting stage is released from hepatocytes. We present here a quantitative, real-time analysis of the fate of parasites transmitted in a rodent system. We describe previously unrecognized steps in the parasite's journey to the liver of the host, which are likely to play an important role in the host immune response.     

Appearance and maturation of voltage-dependent conductances in solitary spiking cells during retinal regeneration in the adult newt

Summary Electrical membrane properties of solitary spiking cells during newt (Cynops pyrrhogaster) retinal regeneration were studied with whole-cell patch-clamp methods in comparison with those in the normal retina.The membrane currents of normal spiking cells consisted of 5 components: inward Na⁺ and Ca⁺⁺ currents and 3 outward K⁺ currents of tetraethylammonium (TEA)-sensitive, 4-aminopyridine (4-AP)-sensitive, and Ca⁺⁺-activated varieties. The resting potential was about -40mV. The activation voltage for Na⁺ and Ca⁺⁺ currents was about -30 and -17 mV, respectively. The maximum Na⁺ and Ca⁺⁺ currents were about 1057 and 179 pA, respectively.In regenerating retinae after 19–20 days of surgery, solitary cells with depigmented cytoplasm showed slowrising action potentials of long duration. The ionic dependence of this activity displayed two voltage-dependent components: slow inward Na⁺ and TEA-sensitive outward K⁺ currents. The maximum inward current (about 156 pA) was much smaller than that of the control. There was no indication of an inward Ca⁺⁺ current.During subsequent regeneration, the inward Ca⁺⁺ current appeared in most spiking cells, and the magnitude of the inward Na⁺, Ca⁺⁺, and outward K⁺ currents all increased. By 30 days of regeneration, the electrical activities of spiking cells became identical to those in the normal retina. No significant difference in the resting potential and the activation voltage for Na⁺ and Ca⁺⁺ currents was found during the regenerating period examined.     

Neurite-Promoting Factor in Conditioned Medium from RN22 Schwannoma Cultures: Bioassay, Fractionation, and Properties

Abstract: On polyornithine (PORN) substrata dissociated 8-day chick embryo ciliary ganglionic neurons will survive if the culture medium is supplemented with Ciliary Neuronotrophic Factor. However, neuritic growth will not occur unless the substratum is derivatized with a PORN-bindable Neurite Promoting Factor (PNPF). In this preliminary study we report that soluble PNPF can be (1) assayed by a convenient in vitro system; (2) obtained in relatively large amounts from serum-free media conditioned over RN22 Schwannoma cultures; (3) concentrated by using Amicon XM100 ultrafiltration; and (4) separated from nearly all of the non-active protein by using ion-exchange chromatography. The partially purified PNPF can be concentrated using XM100 and is heat- and protease-sensitive. In the course of these fractionation studies we observed in some cases a concentration-dependent interference with the expression of PNPF activity in the bioassay; we propose graphical methods to permit the simultaneous determination of PNPF and the extent of such interference. Different treatments that affected the interference property did not always affect PNPF activity in a reciprocal manner, leaving open the possibility that the interference with PNPF activity results from reversible alteration of the PNPF molecule, or that there exists a separate interfering agent.     

Changes in retinal neuronal populations in the DBA/2J mouse

DBA/2J (D2) mice develop a form of progressive pigmentary glaucoma with increasing age. We have compared retinal cell populations of D2 mice with those in control C57BL/6J mice to provide information on retinal histopathology in the D2 mouse. The D2 mouse retina is characterized by a reduction in retinal thickness caused mainly by a thinning of the inner retinal layers. Immunocytochemical staining for specific inner retinal neuronal markers, viz., calbindin for horizontal cells; protein kinase C (PKC) and recoverin for bipolar cells, glycine, -aminobutyric acid (GABA), choline acetyltransferase (ChAT), and nitric oxide synthase (NOS) for amacrine cells, and osteopontin (OPN) for ganglion cells, was performed to detect preferentially affected neurons in the D2 mouse retina. Calbindin, PKC, and recoverin immunoreactivities were not significantly altered. Amacrine cells immunoreactive for GABA, ChAT, and OPN were markedly decreased in number, whereas NOS-immunoreactive amacrine cells increased in number. However, no changes were observed in the population of glycine-immunoreactive amacrine cells. These findings indicate a significant loss of retinal ganglion and some amacrine cells, whereas glycinergic amacrine cells, horizontal, and bipolar cells are almost unaffected in the D2 mouse. The reduction in amacrine cells appears to be attributable to a loss of GABAergic and particularly cholinergic amacrine cells. The increase in nitrergic neurons with the consequent increase in NOS and NO may be important in the changes in the retinal organization that lead to glaucomain D2 mice. Thus, the D2 mouse retina represents a useful model for studying the pathogenesis of glaucoma and mechanisms of retinal neuronal death and for evaluating neuroprotection strategies.Jung-Il Moon and In-Beom Kim contributed equally to this work.This work was supported by a Korea Research Foundation Grant (FP 0005) and by BK 21 in Korea.     

Evolution of the lumbo-sacral neural crest in the avian embryo: Origin and differentiation of the ganglionated nerve of Remak studied in interspecific quail-chick chimaerae

Summary Isotopic and isochronic transplantation of fragments of quail neural tube into chick demonstrates that neural and glial cells of the entire ganglion of Remak (RG) arise from the lumbo-sacral level of the neural crest.The ganglioblasts first accumulate in the mesorectum (stage 24 of Hamburger and Hamilton, in the chick and I8 of Zacchei in the quail) and subsequently migrate cranially.Histochemical studies have been carried out on the rectal and cloacal parts of the quail RG at various stages of development. Cholinesterase activity can be detected as soon as the primordium is in place and the intensity of the reaction increases rapidly. During morphogenesis of the cloacal region the RG and the pelvic plexus become intimately associated. Catecholamine-containing cells are found first in the pelvic plexus, then in the cloacal part of the RG. Fluorescent cells are often grouped close to blood vessels and associated with non-fluorescent ganglia. Cranial to the level of the bursa of Fabricius, the RG is composed only of non-fluorescent neurons whatever the developmental stage considered (up to 1 day after hatching).The developmental capabilities of the RG of the 5-day quail have been tested by transplanting various parts of the hind-gut with the dorsal mesentery onto the chorio-allantoic membrane. Catecholamine-containing cells develop only in grafts including the cloacal region.By using quail-chick chimaerae in which the RG belongs to the quail while mesentery and gut are of chick origin, it was possible to show that neurons which develop in the graft (i.e. in the absence of preganglionic innervation), send nerve fibres into the gut wall. Moreover some neuroblasts located in the primordium of the RG migrate into the gut wall and give rise to some enteric ganglion cells. The contribution of the lumbo-sacral neural crest to the enteric ganglia, by this route, is discussed.List of Abbreviations in Text FIF formol-induced fluorescence - H & H Hamburger and Hamilton - Z Zacchei - CAM chorio-allantoic membrane - SIF small intensely fluorescent (cells)     

无水酒精和曲安奈德对腱鞘囊肿的疗效分析

目的:对比无水酒精和曲安奈德治疗腱鞘囊肿的疗效.方法:收集2010年2月至2011年8月在本院门诊治疗的腱鞘囊肿痛患88例,随机分为无水酒精治疗组43例(治疗组)和曲安奈德治疗组45例(对照组).利用SPSS15.0统计软件对数据进行描述性及”t”检验进行分析.结果:2组病患均获得随访,对照组好转率为84.4％(38/45),无水酒精组的好转率为97.8％(42/43),无水酒精组的复发率显著降低(P＜0.05).两个组别的不良反应均可耐受.结论:无水酒精治疗腱鞘囊肿优于曲安奈德,疗效显著.     

Implementing Dynamic Clamp with Synaptic and Artificial Conductances in Mouse Retinal Ganglion Cells

Ganglion cells are the output neurons of the retina and their activity reflects the integration of multiple synaptic inputs arising from specific neural circuits. Patch clamp techniques, in voltage clamp and current clamp configurations, are commonly used to study the physiological properties of neurons and to characterize their synaptic inputs. Although the application of these techniques is highly informative, they pose various limitations. For example, it is difficult to quantify how the precise interactions of excitatory and inhibitory inputs determine response output. To address this issue, we used a modified current clamp technique, dynamic clamp, also called conductance clamp ^{1, 2, 3} and examined the impact of excitatory and inhibitory synaptic inputs on neuronal excitability. This technique requires the injection of current into the cell and is dependent on the real-time feedback of its membrane potential at that time. The injected current is calculated from predetermined excitatory and inhibitory synaptic conductances, their reversal potentials and the cell''s instantaneous membrane potential. Details on the experimental procedures, patch clamping cells to achieve a whole-cell configuration and employment of the dynamic clamp technique are illustrated in this video article. Here, we show the responses of mouse retinal ganglion cells to various conductance waveforms obtained from physiological experiments in control conditions or in the presence of drugs. Furthermore, we show the use of artificial excitatory and inhibitory conductances generated using alpha functions to investigate the responses of the cells.     

A Laser-induced Mouse Model of Chronic Ocular Hypertension to Characterize Visual Defects

Glaucoma, frequently associated with elevated intraocular pressure (IOP), is one of the leading causes of blindness. We sought to establish a mouse model of ocular hypertension to mimic human high-tension glaucoma. Here laser illumination is applied to the corneal limbus to photocoagulate the aqueous outflow, inducing angle closure. The changes of IOP are monitored using a rebound tonometer before and after the laser treatment. An optomotor behavioral test is used to measure corresponding changes in visual capacity. The representative result from one mouse which developed sustained IOP elevation after laser illumination is shown. A decreased visual acuity and contrast sensitivity is observed in this ocular hypertensive mouse. Together, our study introduces a valuable model system to investigate neuronal degeneration and the underlying molecular mechanisms in glaucomatous mice.     

Apport de l’imagerie hybride TEMP/TDM dans la détection des ganglions sentinelles : à propos de 32 cas

Objectives

Retrospective evaluation of the SPECT/CT role in the Sentinel Lymph Node identification.

Patients and methods

Thirty-two patients underwent a lymphoscintigraphy with SPECT/CT imaging. Those patients presented several cancer types (16 melanoma, one squamous cell carcinoma, three breast cancers, eight vulvar cancers, three cervical cancers).

Results

The scintigraphic detection rate was 81% with planar imaging while this rate was 89% with SPECT/CT. The SPECT/CT provided an additional quantitative information in 66% cases. Moreover, the quality of the interpretation was better in two different conditions (planar interpretation followed by routine and blinded SPECT/CT interpretation) with SPECT/CT. In our study, the false negative rate is 4.5%.

Conclusions

SPECT/CT provides quantitative and qualitative informations in the sentinel lymph node detection. Therefore, it can be a valuable tool for the surgeon to find and harvest the sentinel lymph node especially where the lymphatic drainage pattern can be unusual or hard to predict (cervical or trunk localisation). It's a new tool for preoperative detection and it can decrease the false negative rate.