Criterion-related validity and test–retest reliability of the 20 m Square Shuttle Test

We assessed validity and reliability of the new 20m square shuttle run test (SST) for predicting maximal oxygen uptake (V O(2max)) and compared it with its predecessor, the 20m Multistage Shuttle Run Test (MST). In a repeated-measures randomised-block design, 74 healthy adult males performed the SST, the MST and a treadmill test (TT). To assess reliability, 40 of the total 74 volunteers were randomly-selected to perform the SST and MST twice. Unlike the SST (p>0.05), mean predicted V O(2max)(V predO(2max)) from the MST was significantly increased from that measured during the TT (p<0.05). The V predO(2max) from SST and MST correlated with TT V O(2max) at r=0.95 (p<0.001) and r=0.63 (p<0.001), respectively. Prediction error of SST was -0.3+/-3.3mlkg(-1)min(-1) with a coefficient of variation of +/-3.5%, while the equivalent values for MST were 4.2+/-7.3mlkg(-1)min(-1) and +/-7.4%. Mean test-retest V predO(2max) did not differ for both SST and MST (p>0.05), while the corresponding test-retest correlation coefficients were r=0.85 (p<0.001) and r=0.72 (p<0.001). Reliability errors in 95% limits of agreement were 0.3+/-4.8 and 0.6+/-6.8mlkg(-1)min(-1) while coefficients of variation were +/-5.2% and +/-6.8% for the SST and MST, respectively. It is concluded that SST is a more valid proxy than MST for predicting laboratory V O(2max) based on the current procedures, while both tests are sufficiently reliable in healthy male adults.     

The Detectability and Localization Accuracy of Implanted Fiducial Markers Determined on In-Room Computerized Tomography (CT) and Electronic Portal Images (EPI)

Many different methods of image guidance are available for radiotherapy treatment (IGRT). The aims of the study were (1) to determine the optimal diameter of gold markers for IGRT to the prostate; (2) to compare, using the Siemens Primatom, the relative merits of in-room computerized tomography (CT) and electronic portal image (EPI) for locating the marker seeds. Gold markers of differing widths were embedded in 2 phantoms (perspex slabs and anthropomorphic). Images were acquired with an amorphous silicon flat panel detector (Siemens Optivue 500) and with the in-room CT scanner (Siemens Somatom Balance). The EPIs were reviewed independently by 6 operators to determine which diameter marker could be best visualized. The optimal marker technique was determined by comparing the investigators' observed marker co-ordinates with the known locations within the phantom. The visibility of all markers on anterior-posterior EPIs was 100%. On the lateral EPI, of a possible 180 visualizations of 1.2-, 1.0-, and 0.8-mm diameter markers, 176 (97.8%), 151 (83.9%), and 132 (73.3%), respectively, were successful. On EPI, the average deviation of fiducial markers from the known position was less than 0.5 mm in any direction. On CT, the largest deviation (2.17 mm) of markers from the known coordinate position was in the superior-inferior direction, reflecting the 3.0-mm slice thickness used. EPI accurately located internal markers in all dimensions. The availability of “gold standard” CT imagery at the treatment unit does not improve how accurately the position of markers in a phantom can be defined compared with EPI. However, CT imagery does provide important soft tissue information, the benefits of which are being investigated further.     

Unexpected lability of cysteine acetamidomethyl thiol protecting group Tyrosine ring alkylation and disulfide bond formation upon acidolysis

Cleavage and deprotection of the peptidyl resin H-Asn-Gly-Gly-Cys(Acm)-Glu(OBu^t)-Gln-Tyr(Bu^t)-Cys(Acm)-Ser(Bu^t)-Asp(OBu^t)-[(p-alkoxy)benzyloxy polystyrene resin] using standard conditions with various trifluoroacetic acid-containing mixtures were found to result in partial removal of ordinarily acid-stable S-Acm groups. Thus, apart from the desired peptide H-Asn-Gly-Gly-Cys(Acm)-Glu-Gln-Tyr-Cys(Acm)-Ser-Asp-OH, a disulfide-cyclic peptide derivative was also isolated. Furthermore, it was found that in another major by-product of the peptide resin cleavage the tyrosine side chain had been alkylated with an Acm group in a position ortho to the phenolic function. The formation of both by-products could be suppressed by carrying out the cleavage/deprotection reaction at higher dilution and by inclusion of scavengers such as phenol. An authentic sample of the disulfide-cyclic peptide was obtained by oxidation of H-Asn-Gly-Gly-Cys-Glu-Gln-Tyr-Cys-Ser-Asp-OH using Ellman's reagent. © Munksgaard 1997.     

L—天门冬酰胺酶产生菌的快速筛选方法

采用一种简易，快速、微量的奈斯勒试剂显色法，可直接从细菌固体培养物中筛选出产生Ｌ－天门冬酰胺酶的细菌。该法适用于从大量菌株中快速筛选Ｌ－天门冬酰胺酶产生菌。     

N-Cyclohexyl-N′ -isopropylcarbodiimide: a hybrid that combines the structural features of DCC and DIC

N-Cyclohexyl-N′ -isopropylcarbodiimide was prepared and used for peptide couplings by various procedures. Reaction between Z-Val and Gly-OEt was used for yield studies and determination of the extent of the side reaction in solution. The value of this reagent for solid peptide synthesis was demonstrated by the synthesis of sequences comprising the 65–74 residues of acyl carrier protein. The efficiency of activation was determined by competition experiments. From all these studies the conclusion can be drawn that N-cyclohexyl-N′-isopropylcarbodiimide is comparable to or even better than the commonly used DCC for mediation of peptide bond formation in solid phase synthesis. By virtue of the solubility of N-cyclohexyl-N′-isopropylurea in dichloromethane, the carbodiimide seems to be a good candidate for practical execution of peptide bond formation by the standard carbodiimide procedure.     

4160型甲醛分析仪与酚试剂法测定空气中甲醛浓度的对比研究

目的 寻找操作简便、快速的测定室内甲醛浓度的仪器。方法 应用酚试剂比色法与美国INTERSCAN公司提供的4160型便携式甲醛分析仪进行了现场测试,并对测试结果进行配对t检验。结果 两种方法测定的不同甲醛浓度之间差异无显著性(低浓度:t=0.400.05;中浓度:t=0.830.05;高浓度:t=0.670.05),并将两种方法测得的数据进行相关分析,其回归方程式:y=0.963 8x+0.012 35,相关系数为0.995 0。结论 4160型甲醛分析仪可以用于公共场所及室内甲醛浓度的测定。     

High‐throughput peptide synthesis and peptide purification strategy at the low micromol‐scale using the 96‐well format

Abstract: The increasing demand for short‐ and medium‐sized peptides in many fields of biological, medical and pharmaceutical research requires optimized and universally applicable high‐throughput synthesis and purification techniques at the low‐µmol scale. Here, we describe a continuous peptide synthesis/purification approach using the 96‐well format. First, a µmol scale peptide synthesis on resin beads was optimized on a novel miniaturized 96‐reaction vessel block employing standard Fmoc/tBu‐chemistry. Almost 90% of the synthesized peptides contained the target sequence as the main component, as judged from matrix‐assisted laser desorption/ionization (MALDI) mass spectra. Impurities were mostly related to partially protected peptides. Second, we tested the applicability of ion pair reversed‐phase solid‐phase extraction (IP–RP–SPE) to purify individual peptides. Depending on the length and predicted hydrophobicity of the peptides, elution was performed with 25 or 35% aqueous acetonitrile in the presence of 0.1% trifluoroacetic acid (TFA). Thus, scavengers used during TFA cleavage and partially protected peptides carrying very hydrophobic protecting groups were effectively removed. Using a narrow step gradient, the target peptides were even separated from deleted sequences and protected peptides with similar hydrophobicities. Third, we combined the µmol‐scale synthesis in the 96‐well format with purification by IP–RP–SPE on a 96‐well micro‐extraction plate format. This simple, fast and parallel approach was tested on 12‐mer and 15‐mer peptides to map epitopes of T‐ and B‐cell clones, respectively. Approximately 80% of all peptides were obtained at purities > 90% without purification by RP–HPLC. In summary, this novel approach has several advantages: (i) the µmol‐scale reduced the cost of peptide synthesis, (ii) large numbers of peptides were purified faster, (iii) the volumes of eluents and waste were significantly reduced, and (iv) the RP–HPLC column was not contaminated with hydrophobic impurities.     

Synthesis of L-2-amino-4-hexynoic acid and derivatives

A synthesis is described of optically pure L-2-amino-4-hexynoic acid and its derivatives, which can serve as potentially useful precursors for the preparation of highly tritium labeled norleucine-containing peptides, as well as other side-chain modified peptides. Catalytic tritiation of one derivative of this acetylenic amino acid afforded the (³H)-L-norleucine derivative with a specific activity of 115 ± 5 Ci/mmol.     

金双歧联合蒙脱石散治疗小儿病毒性肠炎的疗效

〔摘 要〕 目的：探讨金双歧联合蒙脱石散治疗小儿病毒性肠炎的效果。 方法：选取厦门大学附属第一医院杏林分院 2019 年 10 月至 2020 年 9 月收治的病毒性肠炎患儿 79 例,根据治疗方案不同分为观察组（41 例）和对照组（38 例）。 对照组予以蒙脱石散治疗,观察组予以金双歧联合蒙脱石散治疗,比较两组患儿疗效、不良反应情况、治疗前后炎症 因子水平和心肌损害情况。 结果： 观察组患儿治疗总有效率为 97.56 %,高于对照组的 81.58 %,差异具有统计学意义 （P ＜ 0.05）。治疗后,两组患儿血清肿瘤坏死因子 –α（TNF–α）、白细胞介素 –6（IL–6）、IL–10 水平均较治疗前明显降低, 且观察组低于对照组,差异具有统计学意义（P ＜ 0.05）。治疗后,两组患儿血清肌酸激酶（CK）、肌酸激酶同工酶 MB （CK–MB）、心肌肌钙蛋白 I（cTnI）水平均较治疗前明显降低,且观察组低于对照组,差异具有统计学意义（P ＜ 0.05）。 两组患儿治疗过程中均未见不良反应。 结论：金双歧联合蒙脱石散治疗小儿病毒性肠炎能显著缓解炎症状态,减轻心肌 损害,效果显著,安全性高。