北京春季沙尘天气特征和预报

根据北京地区资料分析了沙尘的年代变化、月变化,春季是沙尘天气的高发期并以浮尘和扬沙为主。造成沙尘天气的冷空气主要有三条路径,它与蒙古气旋、冷锋、高空急流等大尺度天气系统紧密相连。     

除草剂靶标酮醇酸还原异构酶(KARI)研究进展

酮醇酸还原异构酶(KARI)是植物和微生物体内支链氨基酸生物合成的关键酶之一,可以作为设计除草剂的靶标,通过抑制酶的活性中断支链氨基酸的合成使植物死亡,达到除草目的。文章综述了KARI的催化性质、晶体结构以及作为除草剂靶标的研究现状。     

苦皮藤素类似物的合成与结构鉴定

以苦皮藤Celastrus angulatus Max.提取物水解产物中的多羟基β-二氢沉香呋喃为原料,合成了对粘虫Mythimna separata具有毒杀活性的苦皮藤素(Celangulin)类似物,并在活性追踪的指导下分离得到了两个具有杀虫活性的苦皮藤素类似物 A和B, 其结构经核磁共振谱、快原子轰击质谱、高分辨质谱等波谱学方法鉴定为2β,6α,8β,13-四异丁酰氧基-1β,4α,9α-三羟基-β-二氢沉香呋喃及1β,2β,6α,8β,13-五异丁酰氧基-4α,9α-二羟基-β-二氢沉香呋喃。化合物 A和B 均为新化合物,在20 mg/mL的浓度下对三龄粘虫Mythimna separata的胃毒活性(死亡率)分别为89.5%和93.2%。     

Recent advances in molecular mechanisms of oncosis

Oncosis is another form of cell death, which is different from apoptosis. The review will discuss the recent advances of oncosis on pathological morphology, nuclear biochemical changes and molecular mechanisms.     

Cloning and characterization of a bovine genomic fragment homologous to epidermal growth factor genes

Epidermal growth factor (EGF) is a potent mitogen for a variety of cell types. The 53-amino acid mature EGF protein is encoded by sequences in exons 20 and 21 of a gene spanning over 110 kb. In this study, we report the cloning and characterization of 7.5 kb of bovine genomic sequence homologous to exon 19 through 21 from EGF genes from other mammalian species. The cloned gene fragment had an unusual sequence composition in the form of an in-frame TGA codon in the coding sequence. The sequence was expressed at low levels in kidney tissue and the corresponding cDNA contained the TGA codon. The level of similarity between the bovine exonic sequence and the human, porcine, murine, feline, and canine corresponding sequences varied from 64% to 73%; however, when only sequences encoding the mature EGF protein were compared, the level of similarity between the bovine sequence and the sequence from these species was 59% to 66%. The sequence similarity of the deduced mature protein was lower (34% to 39%) than the sequence similarity of the deduced propeptide. Although the cloned sequences could originate from a bovine EGF pseudogene, the possibility exists that they originate from the functional EGF gene. An as yet unidentified mechanism to by-pass the stop codon would allow the synthesis of a functional EGF protein. Alternatively, the cloned sequence could originate from an EGF-like gene.     

Determination of plasma lysosomal enzyme activity and its relationship to severity of injury following blunt vehicular trauma in dogs

Objective: To determine plasma β‐d ‐glucuronidase (βG) activity in the first 4 hours following injury in dogs struck by a motor vehicle, and to evaluate whether the degree of enzyme activity is correlated with the severity of injury. Design: A prospective clinical study. Setting: Veterinary Medical Teaching Hospital. Animals: Thirteen client‐owned dogs that were presented to the Veterinary Hospital of the University of Pennsylvania between June and August 1999 for blunt vehicular trauma. Ten healthy student and staff‐owned dogs served as controls. Interventions: None. Measurements: Plasma was analyzed for βG enzyme activity at the time of presentation (n=13), and 1 and 4 hours (n=7) following presentation to the Emergency Service for blunt vehicular trauma. The results were compared with enzyme activity from healthy controls evaluated serially over 4 hours. Fluorometric analysis using 96‐well microtiter plates was used to perform the enzyme assays. The relationships between presentation (n=13) and 4 hours (n=7) of enzyme activity and 3 indices of metabolic and physical disturbance (serum pH, serum lactate and Animal Trauma Triage (ATT) score) at the time of presentation were also investigated. Main results: Of the 13 dogs, 7 fulfilled the inclusion criteria for comparison of enzyme activity of the trauma over time. A statistically significant difference in βG activity was found in the trauma group (mean 75.6±10.4 U) at 4 hours following presentation compared with controls (mean 48.0±6.4 U). This difference was suggested by 1 hour following presentation (trauma group, mean 70.4±10.9 U; control group, mean 49.8±5.5 U), although it did not reach statistical significance. Thirteen dogs fulfilled the inclusion criteria for comparison of only presentation enzyme activity with trauma severity score, serum lactate, and serum pH. No statistically significant relationship was found between the βd ‐glucuronidase activity and the presenting ATT score, serum lactate concentration, or serum pH at either presentation or 4 hours, although the power of these analyses was low. Conclusions: These results demonstrate that the activity of βG, a lysosomal enzyme, increases significantly in the systemic circulation in dogs 4 hours following blunt trauma. Additional research to include more severely injured dogs, a larger number of dogs, and to follow the course of injury for a longer period of time would be beneficial to further characterize βG activity following blunt trauma.     

Association of hyponatremia and hyperglycemia with outcome in dogs with congestive heart failure

Objective: To evaluate plasma sodium and glucose concentrations in dogs with congestive heart failure (CHF) prior to treatment and evaluate the differences between survivors and non‐survivors. Design: Retrospective study. Animals: Fifty‐nine dogs with CHF prior to receiving cardiac medication. Interventions: None. Measurements and main results: The mean plasma sodium concentration in dogs with CHF was below the reference range (144–156 mmol/L) and significantly lower (P=0.009) in non‐survivors (141±6 mmol/L) compared with survivors (147±4 mmol/L). The mean plasma glucose concentration was above the reference range (76–117 mg/dL) and significantly higher (P=0.004) in non‐survivors (128±52 mg/dL) compared with survivors (100±13 mg/dL). Forty‐four percent of non‐survivors had concurrent low plasma sodium and high plasma glucose concentrations, whereas no survivors had both abnormalities (P<0.0001). Conclusions: Lower plasma sodium and higher plasma glucose are associated with a worse outcome in dogs with CHF.     

A computer program for calculation of doses and prices of injectable medications based on body weight or body surface area

A computer program (CalcAnesth) was developed with Visual Basic for the purpose of calculating the doses and prices of injectable medications on the basis of body weight or body surface area. The drug names, concentrations, and prices are loaded from a drug database. This database is a simple text file, that the user can easily create or modify. The animal names and body weights can be loaded from a similar database. After typing the dose and the units into the user interface, the results will be automatically displayed. The program is able to open and save anesthetic protocols, and export or print the results. This CalcAnesth program can be useful in clinical veterinary anesthesiology and research. The rationale for dosing on the basis of body surface area is also discussed in this article.     

微卫星DNA在动物亲子鉴定中的应用及研究进展

本文概述了微卫星DNA进行亲子鉴定的基本原理与方法,将其用于亲子鉴定的优点以及研究进展,最后对未来的应用进行了展望。     

用甲基丙烯酰氧乙基三甲基氯化铵接枝真丝的研究

为提高真丝纤维织物的抗菌防皱性能,根据真丝纤维蛋白质主体的结构,研究了以硝酸铈铵(CAN)为引发剂,甲基丙烯酰氧乙基三甲基氯化铵(DMC)单体接枝真丝的影响因素,并对DMC接枝真丝后的回潮率、单丝强力和泛黄指数进行了研究,用红外光谱分析了接枝真丝的化学结构。当DMC浓度为06mol/L,CAN的质量分数为10%,pH=3,温度60℃保温120min时,接枝效果较好。接枝后回潮率改善,但泛黄指数有上升趋向,单丝强力也有所下降。红外光谱分析表明单体已接枝到真丝纤维上。