Osmotically induced increase in cerebrovascular permeability to [3H]sucrose

The effect of an intracarotid infusion of a 5 M urea solution on the blood-brain barrier of the rat was measured using the carotid injection technique. The urea infusion increased the amount of sucrose penetrating the barrier. This increased uptake of sucrose was first seen 10–25 sec after the 15 sec urea infusion. By 10 min, sucrose uptake had decreased in some animals.     

Multiple forms of nuclear estrogen receptor in the hypothalamus and pituitary after in vitro exchange with [3H]estradiol or [3H] hydroxytamoxifen

We have examined the sedimentation properties of hypothalamic and pituitary estrogen receptors (ER) translocated to the nucleus by in vivo estradiol (E₂) or nafoxidine treatments in the immature female rat. Nuclear ER were extracted with 0.4 M KC1 and incubated in vitro with saturating concentrations of [³H]E₂under conditions which allowed exchange with endogenous unlabeled ligands (23°C for 1–16 h). Sucrose gradient centrifugation of pituitary extracts from rats treated for 1, 24 or 48 h with E₂ yielded two components, sedimenting at 3 and 4–5S; in hypothalamic extracts the 3S form and variable amounts of a heavier shoulder were observed. After nafoxidine treatment the 4–5S species was present in greater proportions than after E₂. Both species interacted with monoclonal antibodies prepared against cytoplasmic ER from MCF-7 cells to yield more rapidly sedimenting complexes (7–8S). The 4–5S receptor was preferentially labeled in nuclear extracts subjected to exchange with [³H]E₂ for l h in vitro. In addition, nuclear ER from rats treated with [³H]E₂for l h in vivo sedimented at about 5S. We also investigated the direct binding of [³H]4-hydroxytamoxifen to nuclear ER. A single 4.2–4.3S component was present in both the hypothalamus and pituitary; this peak was displaced to about 7.5S after incubation with antibodies to MCF-7 ER. In the same nuclear preparations the 3S receptor predominated after exchange with [³H]E₂;however, a 1000-fold excess of unlabeled nafoxidine or hydroxytamoxifen abolished the 3S peak. These results suggest that 4–5S nuclear ER may give rise to the 3S form through degradation by endogenous proteases and that binding of antiestrogens to the larger species may interfere with this conversion.     

Reduced ocular glucose transport and increased non-electrolyte permeability in rats with retinal degeneration (RCS)

The transport kinetics across the plasma-ocular barriers of labeled molecules including urea, D-glucose, 3-0-methyl-D-glucose, L-glucose, and sucrose were studied in adult RCS rats and compared to control albino Sprague-Dawleys (SD). Results indicate that substances that passively cross the plasma-aqueous and plasma-vitreous barriers (urea, sucrose, L-glucose) do so more readily in the RCS rat especially via the trans-retinal route. By contrast, D-glucose, which penetrates the ocular barriers of the control rat by a carrier-mediated mechanism was found to cross the ocular barriers of the RCS rat at a reduced rate. Thus, the ocular barriers of the RCS rat with well developed retinal degeneration demonstrate an increase in passive permeability and a reduction in ability to perform their membrane transport function (D-glucose). The permeability defect was more pronounced in the blood-vitreous barrier than in the blood-aqueous barrier.     

Isolation and characterization of ovine prolactin and growth-hormone messenger RNAs

Methods are described in this paper for obtaining and characterizing highly enriched preparations of ovine prolactin (PRL) and growth-hormone (GH) messenger RNAs. Purification steps include phenol extraction, oligo-(dT)-cellulose chromatography, sucrose-gradient ultracentrifugation and polyacrylamide-gel electrophoresis. This sequence of procedures results in messenger preparations that are about 92% pure for prolactin mRNA and 78% pure for the growth-hormone mRNA species. Thus, these two closely related mRNAs can be isolated from the same tissue source at a purity adequate for cloning and nucleic acid hybridization experiments. Translation experiments with the cap analogue 7-methylguanosine and end-labeling of the nucleic acid before and after β-oxidation indicate that both messages possess blocked 5'-termini and that these are part of previously described cap structures. Polyadenosine tracts of 30–160 residues were found at the 3'-ends of both purified species. Finally, sizing experiments suggest both mRNAs contain approx. 30% more bases than accounted for by the coding regions and the poly(A)-tracts. Their physical characteristics thus agree with those of most eucaryotic messages to date.     

A comparison of the in vivo uptake of [H]GABA into rat celebral cortex and dorsal medulla following topical application

The penetration of [³H]GABA and [¹⁴C]sucrose from the dorsal surface of the rat medulla and cerebral cortex was studied in vivo. The levels of both declined exponentially from the surface of both regions and were decreased by raised potassium levels and the presence of GABA uptake inhibitors. Inhibition of GABA metabolism increased the amounts of ³H recovered particularly after long incubation periods. More [³H]GABA and [¹⁴C]sucrose was taken up into the cerebral cortex than the medulla, and more [³H]GABA than [¹⁴C]sucrose was taken up in both regions.     

Identification of the heparin binding site on adeno-associated virus serotype 3B (AAV-3B)

Adeno-associated virus is a promising vector for gene therapy. In the current study, the binding site on AAV serotype 3B for the heparan sulfate proteoglycan (HSPG) receptor has been characterized. X-ray diffraction identified a disaccharide binding site at the most positively charged region on the virus surface. The contributions of basic amino acids at this and other sites were characterized using site-directed mutagenesis. Both heparin and cell binding are correlated to positive charge at the disaccharide binding site, and transduction is significantly decreased in AAV-3B vectors mutated at this site to reduce heparin binding. While the receptor attachment sites of AAV-3B and AAV-2 are both in the general vicinity of the viral spikes, the exact amino acids that participate in electrostatic interactions are distinct. Diversity in the mechanisms of cell attachment by AAV serotypes will be an important consideration for the rational design of improved gene therapy vectors.     

蔗糖铁注射液联合红细胞生成素治疗维持性血液透析患者肾性贫血的疗效与安全性

目的 比较静脉应用蔗糖铁与口服多糖铁复合物对使用红细胞生成素.的维持性血液透析患者的肾性贫血的疗效与安全性.方法 采用同期随机对照研究,将接受维持性m液透析肾性贫血患者42例,随机分为静脉组和口服组各21例,分别给予蔗糖铁静脉推注和口服铁剂治疗,比较2组患者贫血治疗的效果及不良反应发生情况.结果 治疗后,血红蛋白(Hb)、红细胞压积(HCT)、血清铁蛋白(SF)、血清转铁蛋白饱和度(TSAT)的升高,静脉组较口服组差异有统计学意义(P<0.05);静脉组不良反应少于口服组(P<0.05).结论 在伴有缺铁的维持性血液透析患者肾性贫血的治疗中,蔗糖铁升高Hb的作用较口服铁剂更快,且不良反应发生率更低.     

Electrophysiological and molecular mechanisms of protection by iron sucrose against phosphine-induced cardiotoxicity: a time course study

Abstract

The present study was designed for determining the exact mechanism of cytotoxic action of aluminum phosphide (AlP) in the presence of iron sucrose as the proposed antidote. Rats received AlP (12?mg/kg) and iron sucrose (5–30?mg/kg) in various sets and were connected to cardiovascular monitoring device. After identification of optimum doses of AlP and iron sucrose, rats taken in 18 groups received AlP (6?mg/kg) and iron sucrose (10?mg/kg), treated at six different time points, and then their hearts were surgically removed and used for evaluating a series of mitochondrial parameters, including cell lipid peroxidation, antioxidant power, mitochondrial complex activity, ADP/ATP ratio and process of apoptosis. ECG changes of AlP poisoning, including QRS, QT, P-R, ST, BP and HR were ameliorated by iron sucrose (10?mg/kg) treatment. AlP initiated its toxicity in the heart mitochondria through reducing mitochondrial complexes (II, IV and V), which was followed by increasing lipid peroxidation and the ADP/ATP ratio and declining mitochondrial membrane integrity that ultimately resulted in cell death. AlP in acute exposure (6?mg/kg) resulted in an increase in hydroxyl radicals and lipid peroxidation in a time-dependent fashion, suggesting an interaction of delivering electrons of phosphine with mitochondrial respiratory chain and oxidative stress. Iron sucrose, as an electron receiver, can compete with mitochondrial respiratory chain complexes and divert electrons to another pathway. The present findings supported the idea that iron sucrose could normalize the activity of mitochondrial electron transfer chain and cellular ATP level as vital factors for cell escaping from AlP poisoning.     

Antiviral phenolics from Antenoron filiforme var. neofiliforme

Abstract

Two new phenolics, 1,3-di-O-p-coumaroyl-2′,6′-di-O-acetylsucrose (1) and quercetin 3-O-β-D-apiofuranoyl-(1→2)-α-L-rhamnopyranoside (2), along with nine known compounds (3–11), were isolated from the whole plants of Antenoron filiforme var. neofiliforme. Their chemical structures were characterized on the basis of various spectroscopic techniques. This is the first report of the isolation of phenylpropanoid sucrose (1, 3–4) from the genus Antenoron. The bioassay results showed that compound 11 exhibited antiviral activity against the Coxsackie virus B3 (CVB3).