茯苓多糖对ApoE-/-AS小鼠肝脏脂质沉积及胆固醇逆向转运相关蛋白表达的影响＊

目的 探讨茯苓多糖对载脂蛋白E基因敲除（ApoE^-/-）动脉粥样硬化（Atherosclerosis，AS）小鼠肝脏脂质沉积及胆固醇逆向转运的影响。方法 采用随机数字表法将30只ApoE^-/-小鼠随机分为模型组、茯苓多糖组、辛伐他汀组，每组10只，10只C57BL/6J小鼠作为正常组。正常组给予基础饲料喂饲，其余小鼠给予高脂饲料喂饲12周。茯苓多糖组以0.2 g/kg/d灌胃，辛伐他汀组以2.275 mg/kg/天灌胃，正常组和模型组给予等体积生理盐水灌胃，共干预4周。全自动生化分析仪检测小鼠血清三酰甘油（TG）、总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）水平，苏木素-伊红（HE）染色观察小鼠肝脏病理形态学变化，油红O染色观察小鼠肝脏脂质沉积情况，ELISA检测各组小鼠血清载脂蛋白A1 （ApoA1）、对氧磷酶-1（PON1）含量，Real-time RT-qPCR法及Western Blot法检测肝脏胆固醇酯转运蛋白（CETP）、磷脂转运蛋白（PLTP）、卵磷脂胆固醇酰基转移酶（LCAT）mRNA及蛋白表达。结果 与正常组比较，模型组小鼠血清TG、TC、LDL-C含量均明显上升，HDL-C含量明显下降（P<0.01），肝细胞脂肪变性明显，肝脏脂质沉积明显，小鼠血清ApoA1、PON1含量均明显下降（P<0.01），小鼠肝脏CETP、PLTP mRNA及蛋白表达明显上升，LCAT mRNA及蛋白表达明显下降（P<0.01）。与模型组相比，茯苓多糖组血清TG、TC、LDL-C含量均显著下降（P<0.01），HDL-C含量呈上升趋势（P>0.05），肝细胞脂肪变性、脂质沉积程度均有所减轻，茯苓多糖组ApoA1含量明显上升（P<0.01），PON1含量呈上升趋势（P>0.05），茯苓多糖组CETP、PLTP mRNA及蛋白表达有所下降，LCAT mRNA及蛋白表达有所上升（P<0.05，P<0.01）。结论 茯苓多糖可能通过调控血脂水平与胆固醇逆向转运过程，改善ApoE^-/- AS小鼠肝脏脂质沉积，进而发挥防治AS作用。     

Potassium transport in Langendorff-perfused mouse hearts assessed by 87Rb NMR spectroscopy.

We studied the fluxes of a potassium congener (Rb(+)) in mouse hearts by (87)Rb MRS at 8.4T. The hearts were loaded with Rb(+) by perfusion with Krebs-Henseleit buffer, in which 50% of K(+) was substituted with Rb(+). We initiated Rb(+) efflux by changing the perfusion medium to Rb(+)-free buffer. Spectra were acquired every 1.85 min, and the kinetics of Rb(+) transport were analyzed by means of monoexponential fits. The rate constants of Rb(+) uptake and efflux were 0.0680 +/- 0.0028 and 0.0510 +/- 0.0051 min(-1), respectively (approximately 30% faster than in the rat heart). The ATP-sensitive potassium channel opener, P-1075 (5 microM), and mitochondrial uncoupler, 2,4-dintrophenol (50 microM), activated Rb(+) efflux from mouse hearts by approximately 35%. The mechanisms responsible for the differences in Rb(+) uptake and efflux under baseline conditions and stimulation, in comparison with rat hearts, are discussed. These data provide a background for studies of cardiac potassium transport in transgenic mouse strains.     

Motor innervation of the bursalis muscle (nictitating membrane) in the lizard Callopistes maculatus

Summary The motor neurones which innervate the bursalis muscle of the lizard Callopistes maculatus were identified by means of intra-axonal retrograde transport of horseradish peroxidase. These neurones were distributed in the oculomotor abducens and accessory abducens nuclei. In the oculomotor nucleus one group of neurones was located in the ventral subnucleus of the contralateral side while the other group was found in the dorsolateral subnucleus of the ipsilateral side. In the abducens and accessory abducens nuclei all the neurones were in the ipsilateral side. The accessory abducens cells, although less numerous, were larger and had a prominent dendritic field in close relationship with the nucleus descendens nervi trigemini.     

Wheat germ agglutinin-apoHRP gold: a new retrograde tracer for light- and electron-microscopic single- and double-label studies

In this report, we describe a new colloidal-gold-labelled retrograde tracer, wheat germ agglutinin (WGA) conjugated to enzymatically inactive horseradish peroxidase (apoHRP). This protein gold complex (WGAapoHRP-Au) is a sensitive marker for retrograde tracing of the projections of CNS neurons at the light-microscopic (LM) level when a silver-enhancement procedure is used to detect the gold in the tracer. For electron-microscopic (EM) analysis, the silver-enhanced sections undergo a further gold-toning step. This protects against rapid oxidation and dissolution of the silver precipitate during the osmication procedure. A major advantage of WGAapoHRP-Au is that it can be used in a variety of multiple-labelling studies. When the retrograde transport of the new tracer is combined with that of the fluorescent dye, True Blue, neurons that have bifurcating axons can be readily demonstrated. Simultaneous immunofluorescent detection of the cytochemistry of the double-retrogradely labelled neurons is also possible. In contrast to a WGA-HRP gold complex, the new complex has no enzymatic activity. Thus HRP-based techniques (e.g., anterograde transport of WGA-HRP or peroxidase-antiperoxidase immunocytochemistry) can be performed on tissue that contains retrogradely labelled neurons marked with WGAapoHRP-Au without having to pretreat tissue so as to destroy endogenous HRP enzyme activity. At the EM level, the gold is readily distinguished from DAB immunoreaction product. This makes both LM and EM double-labelling studies possible. The great sensitivity of the new tracer, its compatibility with a variety of aldehyde fixatives, its ease of detection, and the fact that it can be simultaneously used with several fluorescent and HRP-based immunocytochemical and tracing techniques make WGAapoHRP-Au a valuable tool for LM and EM characterization of CNS cytochemistry and connectivity.     

Transcellular retrograde labeling of radial glial cells with WGA-HRP and diI in neonatal rat and hamster

Topographically distinct populations of radial glial cells in the diencephalon and mesencephalon of neonatal rats and hamsters were transcellularly labeled with wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) and with the lipophilic tracer DiI. A comparison of the histological distribution of the two tracers is suggestive of two different mechanisms of transcellular labeling. Intraocular injections of WGA-HRP resulted in the uptake of exogenously applied WGA-HRP by retinal ganglion cells, followed by anterograde axonal transport and exocytosis within the optic target nuclei. In addition to the transneuronal labeling, which is typical of such injections, we observed the transcellular labeling of the processes and somata of radial glial cells that were topographically associated with the terminal fields of the labeled axons. Similar transcellular labeling of radial glial cells associated with the axon terminal fields of the colliculogeniculate projection to the medial geniculate nucleus was observed following injections of WGA-HRP in the inferior colliculus. The transcellular labeling within the radial glial cells was discontinuous and somatopetally concentrated, indicating the existence of a retrograde active transport mechanism within the radial glial processes subsequent to its uptake following release of tracer from axons. This type of labeling can be referred to as transcellular retrograde glioplasmic transport. In contrast, DiI was used as a tracer through its capacity to diffuse within the plasmalemma. Topographically distinct populations of radial glial cells were transcellularly labeled following placements of DiI in the retina, inferior colliculus, or dorsal thalamus of fixed brains. The radial processes of labeled radial glial cells consistently extended into regions that also contained labeled axons. It is likely that the transcellular radial glial labeling with DiI occurred via transmembranous diffusion. These data indicate that a close structural and functional relation exists between axons and glial cells in the developing brain. © 1993 Wiley-Liss, Inc.     

Blood gases, electrolytes and metabolic monitoring in children with acute failure of vital functions

The priority of direct monitoring of blood gases in Paediatric Intensive Care Units (PICU) increased substantially after introduction of the Deep Picture™ method and Oxygen Status Algorithm (OSA) (1) into medical practice. We used the advantages of these methods as a prerequisite for a more detailed and deeper analysis of the blood oxygen profile (2, 3). The aims of the present paper were:

• 1

   To illustrate the applicability of the capacity coefficients β₁₀, β₂₃, β_{5. 4} of the transported oxygen and the "Useful Ratio" (UR) index of the haemoglobin oxygen, previously described by us, and the benefit derived from differentiation of the states of hyperoxia, normoxia and hypoxia; hyperoxaemia, normoxaemia and hypoxaemia on the Blood Oxygen Binding Curve (BOBC) in critically ill newborns, infants and children.
• 2.

   To expand the diagnostic capacity of the Blood Gas Map (BGM) used with the OSA in children and to supplement the arterial oxygen diagnostics with new indices that reflect the relationship between oxygen uptake and oxygen transported in the body.
• 3.

   To share our experience in PICU related to the acid-base-electrolytes relationship and to the possibility of assessing the reno-hepatic regulation according to the changes of the acid-base status in critically ill children.

     

Cellular calcium and sodium regulation,salt‐sensitivity and essential hypertension in African Americans

The predisposition of African Americans to the salt sensitive form of essential hypertension may result from increased freely exchangeable Ca in intracellular Ca stores and a higher cellular Ca turnover (i.e., enhanced Ca entry into and accelerated Ca extrusion from the cytosol). These alterations entail higher activities of Ca extrusion transport systems, including the Na⁺/Ca²⁺ exchanger (NCE), which extrudes Ca in exchange for external Na⁺ , and plasma membrane Ca‐ATPase (PMCA) that extrudes Ca in exchange for external protons. The higher activity of PMCA, coupled with a higher metabolic activity resulting from a rise in freely exchangeable Ca, increase cellular acid load. Adaptive cellular mechanisms must evolve under these conditions, whereby increased activity of the Na/H exchanger (NHE‐1) maintains normal cytosolic pH by enhancing the extrusion of cytosolic protons in exchange for extracellular Na. Cells with increased cellular Ca stores and enhanced Ca turnover may be particularly vulnerable to the factors that inhibit the Na‐pump. By inhibiting the Na‐pump, these factors diminish the transmembrane Na gradient and consequently inhibit the forward mode of the NCE. Since cells from African Americans show increased Ca turnover, they should retain more Ca upon exposure to Na‐pump inhibitors; a heightened sensitivity to Na‐pump inhibitors could therefore underlie the propensity of African Americans and other individuals with accelerated cellular Ca turnover rate to the salt sensitive form of essential hypertension. Accelerated cellular Ca turnover in African Americans also explains their better response to Ca antagonists compared with other antihypertensive drugs.     

Aquaporin 9 (AQP9) Localization in the Adult Dog Testis Excurrent Ducts by Immunohistochemistry

Aquaporins (AQPs) are small, intrinsic membrane proteins that are present in many cell types involved in fluid transport. AQP9 is a major apical water channel that is expressed throughout the efferent ducts, epididymis, and vas deferens, as well as in other regions of the human and rodent male reproductive tract. The target of this study was to examine the expression of AQP9 in epithelial cells in the adult dog efferent ducts, epididymis, and vas deferens. Samples of dog male reproductive tract comprising fragments of the testis; initial segment, caput, corpus, and cauda of the epididymis; and vas deferens were obtained from eight adult mongrel dogs. Immunohistochemistry and Western blotting procedures were used to show AQP9 localization and distribution. AQP9 expression was not detected either in dog seminiferous tubules or rete testis. However, apical labeling for AQP9 was detected in the different regions of epididymis and vas deferens, with the reaction being less intense in the caput epididymis. Thus, AQP9 is abundantly expressed in dog male reproductive tract, in which it is an important apical pathway for transmembrane flow of water and neutral solutes. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Fluid transport and bacterial penetration along root canal fillings

Convective transport of water from the coronal to the apical end of obturated root canals was determined by the movement of an air bubble in a capillary glass tube connected to the apex of the experimental root section using a headspace pressure of 120 kPa (1.2 atm). Water transport through existing voids in the obturated canals could be measured reproducibly in this way. The root canals of 60 human maxillary canines were filled with gutta-percha and sealer by the cold lateral condensation technique. Thirty of these were first exposed to a small motile bacterium, Pseudomonas aeruginosa, growing in a reservoir at the coronal end of each root. After 50 days, two specimens allowed penetration of bacteria to a reservoir at the apical end. All the roots were then assessed quantitatively for convective transport of water. The results were divided into three defined categories: 39 obturated canals were in the‘bacteria tight’category, 14 canals in the 'slight leakage’and 7 canals in the‘gross leakage’category. The two specimens that showed bacterial penetration fell into the slight and gross leakage categories. The previous test for bacterial passage did not statistically influence the fluid transport pattern of these roots which was measured subsequently. These findings indicate that fluids transport through obturated root canals, most of which do not allow the passage of bacteria.