Ascorbate-2-phosphate in red cell preservation. Clinical trials and active components

A red cell additive solution (AS-005) containing ascorbate-2-phosphate (AsP) to maintain 2,3-diphosphoglycerate, plus adenine, phosphate, and mannitol to retain viability and reduce hemolysis, was evaluated by human clinical trials. A crossover design was used with another additive solution (Nutricel AS-3, Cutter Laboratories) serving as the control for each donor. Each additive solution was evaluated at 35 and 42 days of storage. There was no significant difference between the red cell viability of the two storage solutions at either time period. Split-bag, AS-005 in vitro studies at two temperatures (2.5 and 5.5 degrees C), both within the range of 1 to 6 degrees C approved by the American Association of Blood Banks and the Food and Drug Administration, resulted in dramatically different in vitro parameters, including a threefold difference in 2,3-diphosphoglycerate (2,3-DPG), a fivefold difference in glucose, and significant differences in pH and adenosine triphosphate. High-pressure liquid chromatography data confirmed the preliminary report that 1 to 2 percent (wt/wt) oxalate was present in preparations of AsP. In vitro storage data confirmed that oxalate is the active component of AsP that preserves 2,3-DPG during storage.     

Renal duplication artifact in US imaging

To determine the appearance of artifactual renal duplication in ultrasound (US) imaging, the authors analyzed 22 examples of such duplication in 20 patients. The artifact appeared as a duplication of the collecting system in 18, as a suprarenal mass in three, and as upper-pole cortical thickening in one. It occurred in the left kidney in 15 patients, in the right kidney in three, and bilaterally in two. To determine the frequency of the artifact, 50 additional patients were scanned. It was identified in eight of these patients. Imaging characteristics and the results of in vitro modeling proved the artifact was due to sound beam refraction between the lower pole of the spleen or liver and adjacent fat. This artifact is much more common in the left kidney and occurs more frequently in obese patients. Knowledge of the appearance and cause of this artifact should help radiologists avoid diagnostic errors.     

Mediastinal lymph node metastases from bronchogenic carcinoma: detection with MR imaging and CT

Magnetic resonance (MR) imaging and computed tomography (CT) were compared in a prospective study of 48 patients for the detection of metastatic mediastinal lymphadenopathy from bronchogenic carcinoma. The images were interpreted by three experienced radiologists using a five-point rating scale, enabling receiver operating characteristic (ROC) analysis. Imaging results were evaluated against "truth" data based on analysis of surgical specimens from mediastinoscopy and thoracotomy. All MR images were cardiac gated to reduce cardiac motion artifacts in the mediastinum. MR and CT both performed well, as indicated by similar areas under the ROC curves of 0.779 +/- 0.039 for MR imaging and 0.781 +/- 0.038 for CT scanning. No strong correlation between nodal size and metastatic involvement could be found for either MR or CT results. As long as nodal size remains the sole criterion in the detection of metastatic mediastinal lymphadenopathy, MR imaging is unlikely to enable better interpretations than CT scanning.     

Comparison of gonosomal aneuploidy in spermatozoa of normal fertile men and those with severe male factor detected by in-situ hybridization

The purpose of the study was to analyse the frequency of sex-chromosome numerical abnormalities in human spermatozoa of infertile men by using a standardized experimental protocol of double target in-situ hybridization (ISH). The experiments were performed on decondensed sperm heads from 15 infertile patients (six cases of unexplained infertility and nine cases of severe oligoasthenoteratozoospermia). Three men of proven fertility were used as controls. The probes employed recognized the centromeric regions of human X chromosome and the long arm of the Y chromosome. In a smaller number of cases, additional experiments of double ISH were performed using centromeric probes for chromosomes 1 and 17. Signal detection was based on protocols of enzymatic cytochemical reactions. A total of 24,508, 24,679 and 42,285 cells were scored in the control, unexplained infertility and severe male factor groups of patients respectively. In all the patients in the ISH efficiency result was approximately 98%. In controls, unexplained infertility and severe male factor patients, the frequency of morphologically normal sperm cells carrying an abnormal chromosome constitution (XX or YY or XY or > 2 sex chromosomes signals) was 0.86, 0.75 and 1.35% respectively. The value of this last group of patients (severe male factor) was significantly higher than in the other two groups of patients (P < 0.008). The same findings were made using the autosomic probes. Our preliminary data support the possibility of an increased risk from paternal origin sex chromosome aneuploidies in children born after intracytoplasmic sperm injection (ICSI). Further investigations of the cytogenetic constitution of spermatozoa from severe male factor patients is warranted.      

Bayesian hierarchical EMAX model for dose-response in early phase efficacy clinical trials

A primary goal of a phase II dose-ranging trial is to identify a correct dose before moving forward to a phase III confirmatory trial. A correct dose is one that is actually better than control. A popular model in phase II is an independent model that puts no structure on the dose-response relationship. Unfortunately, the independent model does not efficiently use information from related doses. One very successful alternate model improves power using a pre-specified dose-response structure. Past research indicates that EMAX models are broadly successful and therefore attractive for designing dose-response trials. However, there may be instances of slight risk of nonmonotone trends that need to be addressed when planning a clinical trial design. We propose to add hierarchical parameters to the EMAX model. The added layer allows information about the treatment effect in one dose to be “borrowed” when estimating the treatment effect in another dose. This is referred to as the hierarchical EMAX model. Our paper compares three different models (independent, EMAX, and hierarchical EMAX) and two different design strategies. The first design considered is Bayesian with a fixed trial design, and it has a fixed schedule for randomization. The second design is Bayesian but adaptive, and it uses response adaptive randomization. In this article, a randomized trial of patients with severe traumatic brain injury is provided as a motivating example.     

��-Arrestin 1 and 2 stabilize the angiotensin II type I receptor in distinct high-affinity conformations

BACKGROUND AND PURPOSE

The angiotensin II type 1 (AT₁) receptor belongs to family A of 7 transmembrane (7TM) receptors. The receptor has important roles in the cardiovascular system and is commonly used as a drug target in cardiovascular diseases. Interaction of 7TM receptors with G proteins or β-arrestins often induces higher binding affinity for agonists. Here, we examined interactions between AT_1A receptors and β-arrestins to look for differences between the AT_1A receptor interaction with β-arrestin1 and β-arrestin2.

EXPERIMENTAL APPROACH

Ligand-induced interaction between AT_1A receptors and β-arrestins was measured by Bioluminescence Resonance Energy Transfer 2. AT_1A-β-arrestin1 and AT_1A-β-arrestin2 fusion proteins were cloned and tested for differences using immunocytochemistry, inositol phosphate hydrolysis and competition radioligand binding.

KEY RESULTS

Bioluminescence Resonance Energy Transfer 2 analysis showed that β-arrestin1 and 2 were recruited to AT_1A receptors with similar ligand potencies and efficacies. The AT_1A-β-arrestin fusion proteins showed attenuated G protein signalling and increased agonist binding affinity, while antagonist affinity was unchanged. Importantly, larger agonist affinity shifts were observed for AT_1A-β-arrestin2 than for AT_1A-β-arrestin1.

CONCLUSION AND IMPLICATIONS

β-Arrestin1 and 2 are recruited to AT_1A receptors with similar ligand pharmacology and stabilize AT_1A receptors in distinct high-affinity conformations. However, β-arrestin2 induces a receptor conformation with a higher agonist-binding affinity than β-arrestin1. Thus, this study demonstrates that β-arrestins interact with AT_1A receptors in different ways and suggest that AT₁ receptor biased agonists with the ability to recruit either of the β-arrestins selectively, would be possible to design.     

肿瘤相关抗原Tn及其低聚体的合成

目的展示肿瘤相关抗原Tn及其低聚体合成的进展.方法查阅国内外文献,概括肿瘤相关抗原Tn及其低聚体合成的方法.结果肿瘤相关抗原Tn是由糖基供体与保护丝氨酸(苏氨酸)缩合,去保护基后而得,Tn抗原低聚体通过Tn的逐步缩合或直接缩合而得.结论肿瘤相关抗原Tn及其低聚体的合成是肿瘤疫苗研究中的一个热点.     

帕米膦酸二钠的合成

目的：合成二钠３－氨基－１－羟基－亚丙基－二膦酸盐（帕米膦酸二钠）。方法：有,无溶剂的两种合成路线,并对工艺进行改进,所得产物经元素分析,红外光谱,质谱等分析确证结构。结果;两种路线均可合成目标化合物。路线Ａ收率高于路线Ｂ。结论：溶剂的加入使本反应体系均一,有利于产物生成。