首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
The present preliminary study was performed to find out stability of total prostate specific antigen (PSA) and free prostate specific antigen (FPSA) in serum of healthy males as well as in patients of benign and malignant disorders of prostate at various freezing and nonfreezing temperatures and at different duration of time. The results of our study indicated long-term stability of both the analytes in frozen serum. Serum total and free PSA were stable only for three to four days in regular refrigerators in unfrozen states. Clotted blood kept at room temperature (25°C–30°C) did not cause change in concentrations of both the analytes for twenty four hours.  相似文献   

2.
上海百余年来气温日间波动特征及城市化影响   总被引：2，自引：1，他引：1  
史军  崔林丽  田展  薛静 《资源科学》2011,33(5):989-994
基于上海市区(徐家汇)气象站1873年-2009年和上海10个郊县气象站1960年-2009年逐日气温数据,利用气候统计诊断方法分析了上海最高和最低气温在两日间(简称日间)的波动特征及城市化影响,结果表明:1873年-2009年期间,上海最高气温日间降温日数逐渐增多,升温日数逐渐减少,最低气温日间降温日数呈多-少-多-少的年际变化,日间升温日数则呈少-多-少-多的年际变化。上海最高气温日间降温和升温幅度、降温和升温≥5℃日数和最低气温日间降温幅度、降温≥5℃日数都呈现出先增加后减少的年际变化,最低气温日间升温幅度和升温≥5℃日数在20世纪30年代前变化很小,从20世纪60年代至今明显减少。上海城市化增加了最高气温的日间波动幅度,并减少了最低气温的日间波动幅度,使得最高气温日间升温≥5℃日数增加和日间降温≥5℃日数减缓减少,最低气温日间降温和日间升温≥5℃日数均减少。  相似文献   

3.
Prostate Specific Antigen (PSA) has emerged as the most applicable and important tumor marker for carcinoma prostate. In the present study PSA was determined in serum of healthy subjects, patients of benign prostate hypertrophy (BPH) and Carcinoma Prostate (Ca−P) to evaluate its diagnostic efficiency in day to day management of prostate cancer patients and in differentiating patients of early prostate cancer from those with BPH. Receiver operating characteristic curve (ROC) revealed 2 ng/ml and 10 ng/ml cut off serum PSA level for BPH and untreated carcinoma prostate patients (Ca−P). An extremely significant increase (P<0.0001) was observed in mean PSA concentration in BPH patients and adenocarcinoma prostate patients when compared to healthy males. Clinical relevance of PSA was highlighted by a case study of cancer patient prior to any therapy till death.  相似文献   

4.
Fifty patients were evaluated for serum total PSA (Prostate Specific Antigen), free PSA (f-PSA), free/total PSA ratio (f/t PSA ratio) and TPSTM (Tissue Polypeptide Specific Antigen). Fifty patients were clinically evaluated and categorized into BPH (benign prostatic hypertrophy) and CaP (carcinoma prostate) with twenty-five in each category before the serological examination. Serum total PSA concentration is elevated in 80% of BPH cases while it was elevated in all cases of CaP. With total PSA>10ng/mL, f/t PSA ratio was not applicable. For TPSTM, a cell proliferation marker these values were 32% and 92% respectively. The advanced cases of CaP were reflected by the pronounced elevations of PSA and TPStM while f/t PSA ratio was much below the cut-off limit (cut-off limit=0.14). The data suggest that whentotal PSA concentration <10ng/mL, f/t PSA ratio plays a very important role in discriminating BPH and CaP. However, TPSTM can be used as a valuable adjunct in diagnosis and follow-up of prostate cancer patients, especially in differentiating benign from malignant cases.  相似文献   

5.
为了满足对电源监控的需要,本文提出了基于STC89C52单片机的市电中断告警系统实现方案,并详细阐述了系统总体架构、软硬件设计。实践应用表明该系统具有可靠性高、成本低、实现简单等特点,具有良好的应用前景。  相似文献   

6.

Introduction

The collected and shipped blood samples are exposed to a various extra-analytical factors prior to analysis. The aim of the study was to determine the stability of analytes in serum gel tubes and plain tubes exposed to a range of storage temperatures and times after centrifugation.

Materials and methods:

Fifteen healthy volunteers were recruited and venous blood was collected into four tubes, two with and two without gel separator. Analyzing the baseline samples in 30 min, all were stored at 4ºC or 24ºC for 6, 12, 18, 24, 30, 36, 48 and 72 hours and 1 week. Sixteen biochemical anaytes were measured on each sample. Variations remained under the desirable bias considered as clinically insignificant.

Results:

On day three, most analytes remained stable including albumin, protein, creatinine, cholesterol, triglycerides, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), creatine kinase (CK), lactate dehydrogenase (LD) regardless of tube types. Glucose concentration decreased markedly (P = 0.001) beginning from the first hours of storage in plain serum. The stability maximized for the analytes including glucose, total bilirubin, urea nitrogen (BUN), uric acid stored at 4 ºC in gel tubes. Aspartate aminotransferase (AST) activity increased significantly (P = 0.002) up to 48-h, however bias was not significant clinically. High density lipoprotein (HDL) concentration was stable in gel tubes at 24 ºC, in plain tubes at 4 ºC stored up to 36-h.

Conclusion:

Serum gel or non-gel tubes might be used interchangeably for 11 analytes chilled or at 24 ºC, whereas some restrictions must be applied for glucose, AST, BUN, HDL, and uric acid.  相似文献   

7.
The serum PSA is universally accepted as the useful and clinically relevant tumor marker for monitoring therapy and identifying early recurrence in patients of carcinoma prostate throughout the world. However, application of serum PSA is limited to screening for early adenocarcinoma prostate among males above fifty years of age. Serum PSA concentration varies from one population to another in different parts of the world. Many groups of workers have selected 4 ng/ml of serum PSA as upper limit of normal range without giving due consideration for age specific increase in serum PSA. There is no single report available on normal decade wise age specific reference intervals for serum PSA in Indian males. The present study is undertaken to establish age specific reference intervals in healthy Indian males from 20–89 years belonging to subpopulation of Andhra Pradesh from South India. Our results revealed lowest concentration of 95 percentile serum PSA in Indian males compared to other populations globally. Contrary to this, healthy Afro Americans were found to have highest concentration of serum PSA compared to all other populations.  相似文献   

8.
The power to survive prolonged exposure to low temperatures is possessed by various enzymes, including those producing hydrolysis of fats, of carbohydrates, and of proteins, those concerned in biochemical oxidations and reductions, the clotting enzymes and that of alcoholic fermentation. The enzymes retained their catalytic power after exposure, either in situ or in solution in vitro, to temperatures varying from a few degrees above 0° C. to the temperature of liquid air (?180° to ?191° C.). The shortest periods of holding, invariably less that one day and usually less than one hour, were at the temperature of liquid air. The longest period of holding was eighty-nine months at a temperature of ?9.4° to ?12.2° C.The activity of certain of these enzymes, including rennin, zymase, and those hydrolyzing fats, carbohydrates, and proteins, has been studied at low temperatures, varying from that of an ice-box to one of ?9° to ?12° C. While the enzymes produced autolytic digestion or acted on artificial media at these temperatures, the velocity of the reaction was always lessened to a considerable degree.  相似文献   

9.
近年来国际重大突发事件频发,严重威胁了中国及全球粮食安全。文章从生产、消费、流通3个环节分析重大突发事件对粮食安全造成的主要风险。在生产环节,重大突发事件将限制劳动力和农资的投入,进而直接制约粮食的生产;在消费环节,重大突发事件的爆发往往会导致粮食价格的上涨、居民收入水平的下降和食品加工的受阻,进而削弱人们的粮食购买能力和消费能力;在流通环节,重大突发事件可能导致国内粮食运输受阻,以及国际贸易中断,进而阻碍粮食生产和粮食需求的有效对接,加剧粮食危机爆发的风险。中国粮食的高自给率不仅有力地保障了国内粮食安全,更为国际粮食供需安全创造了空间。文章最后对中国粮食安全提出了相应的政策建议。  相似文献   

10.

Introduction:

Studies about vitamin D [25(OH)D] stability in plasma are limited and preanalytical variables such as tube type may affect results. We aimed to evaluate effect of storage conditions, sample type and some preanalytical variables on vitamin D concentration.

Materials and methods:

Blood samples from 15 healthy subjects were centrifuged at different temperatures and stored under different conditions. Serum and plasma 25(OH)D difference, effect of centrifugation temperature and common storage conditions were investigated.

Results:

There was no difference between serum and plasma vitamin D concentration. Centrifugation temperature had no impact on vitamin D concentration. 25(OH)D is stable under common storage conditions: 4 hours at room temperature, 24 hours at 2–8 °C, 7 days at −20 °C, 3 months at −80 °C.

Conclusion:

Vitamin D does not require any special storage conditions and refrigeration. Both serum and plasma can be used for measurement.  相似文献   

11.
The presence of maxima in the power factor-frequency and power factor-temperature curves of dielectrics has been explained by the Maxwell inhomogeneity theory and the Debye theory of polar molecular orientation. In order to ascertain the true cause of these maxima, a study has been made of the power factor of an essentially non-polar material with and without polar materials in dilute solution over extended ranges of frequency, 65 to 7.2 × 106 c.p.s., and temperature, 2.9° C. to 90° C.The non-polar solvent is a mixture of paraffins having a pour point at 55° C. Small power factor maxima, 0.0003 in value, shifting over the audio frequency range with temperature variation, are observed for this solvent alone. Adding 3 per cent. phenol gives rise to molecular orientation maxima restricted largely to frequencies above 107 c.p.s. At the lower temperatures, these maxima are greatly broadened, so that there is apparently a small contribution at power frequencies. Adding 10 per cent. stearic acid gives similar results. The failure of these maxima to shift to lower frequencies at the lower temperatures is due to the failure of the inner viscosity to increase very much in the solid state. The variation of the inner viscosity is calculated from the reciprocals of the short time conductivities since the degree of ionic dissociation is found to be essentially independent of temperature. The viscosity may be regarded as a function of particle size and varies within the medium. Where power factor maxima shift with essentially undiminished magnitude over a wide frequency range at ordinary temperatures, such as those observed here in the solvent above, it is believed that the cause is the orientation of associated or polymerized polar aggregates of such size as to be affected by the larger viscosity changes approaching the macroscopic.In the solid and amorphous states, the limited motion of ions leads to an ionic polarization as indicated by absorption curves of relatively large time constants and by high power factors in the low frequency range. The addition of organic acids greatly increases these effects and also increases the final conductivity. The true short time conductivity is largely caused by almost completely dissociated inorganic material.  相似文献   

12.
“双碳”战略下,未来40年我国电力系统的供需规模仍将持续增长。文章首先对碳中和目标下我国电网体系进行了总体分析,认为未来风电和太阳能发电将逐步成为主体电源,这给电网消纳新能源带来新任务和挑战。在此基础上,阐述了构建新型电力系统的总体思路和建设原则,分析了电网的基本结构和形态。未来远距离输电规模将持续扩大且资源和负荷不平衡,新型电力系统依然存在着电源和负荷逆向分布的显著特征,因此其基本形态仍由大电网构成,并以分布式系统为有效补充。此外,电网中灵活调节资源对于电网的安全运行至关重要,电力市场化运行机制应引导多元主体参与新型电力系统的建设。最后,提出了建设面向碳中和的新型电力系统分阶段实施策略,对建设新型电力系统,实现碳中和有重要指导作用和意义。  相似文献   

13.
Prostate specific antigen (PSA) has long been used as a biological marker for prostatic cancer. Recent studies have demonstrated that PSA synthesis can be induced by steroid hormones in several tissues of women. Menstrual cycle is regulated by the cyclic variation of estradiol and progesterone. This study was undertaken in order to study the correlation of serum PSA to both these corpus luteal hormones. 110 serum samples and 10 saliva samples were collected from healthy women aged 18–45 years of age having normal menstrual cycles. Active PSA DSL-9700 ultrasensitive kit with detection limit 0.001 ng/ml was used to analyze PSA. 38.2 % of all serum samples and 10 % of saliva samples had detectable concentrations of PSA. The serum PSA was highest during mid follicular phase (between 4th and 8th days of cycle). Variation in PSA levels seemed to follow the variations in progesterone with a lag period of 12–14 days, but did not appear to bear any relationship with the estradiol levels.  相似文献   

14.
Dyslipidaemia is a major CVD risk factor in the general population. Current evidence suggests that lipid metabolism is altered in RA due to inflammation, and that use of anti-inflammatory therapy may reverse some of these changes. The objective of our study is to compare the effect of treatment with DMARD on lipid fractions after 6 months of therapy. Forty patients who met the American College of Rheumatology, ACR/EULAR criteria for rheumatoid arthritis, with disease duration of less than 1 year and no prior treatment were included in the study. Thirty healthy volunteers were included as controls. The mean DAS-28 at disease onset was 5.15 ± 1.3. Early Rheumatoid Arthritis (ERA) patients exhibited higher serum levels of total cholesterol (TC) and lowdensity lipoprotein cholesterol (LDL-C) and lower serum high-density lipoprotein cholesterol (HDL-C) levels compared to controls. As a consequence, the atherogenic index of plasma [log (TG/HDL-C)], the atherogenic indices: TC/HDL-C as well as LDLC/HDL-C was significantly higher in ERA patients compared to controls. After 6 months of treatment, there was significant reduction of the DAS 28, HDL-C and Apo A-I improved and Lp(a) decreased significantly. All lipid ratios improved, a phenomenon primarily due to the increase in serum HDL-C levels. These changes were inversely correlated with CRP and ESR. In conclusion, ERA patients are characterized by an atherogenic lipid profile, which improves with DMARD therapy.  相似文献   

15.
A chymotrypsin-like enzyme was purified from rat plasma, involving ammonium sulfate fractionation and chromatographgy on CM-sephadex and red sepharose. The purified enzyme effectively hydrolysed the ester substrates for chymotrypsin (N-acetyl L-tyrosine ethyl ester and N-acetyl L-tryptophan ethyl ester). The Km values for the two substrates were 2.2×10?3M and 9.0×10?3M respectively. The hydrolytic activity of the enzyme was inhibited by phenylmethyl sulfonyl fluoride and tosylphenylalanine chloromethylketone, suggesting the presence of serine and histidine at the active centre. The enzyme exhibited anionic nature and possessed a high molecular weight (MW 71,000) as observed by gel exclusion chromatography on Sephadex G-200. The enzyme was stable upon exposure to pH 7.0–9.0, but was inactivated upon heat treatment at 60°C for 5 min.  相似文献   

16.
Approaches to the stabilization of tumor markers vary depending on the lability of the tumor marker. Thus while merely freezing the serum promptly at ?70°C may be adequate for some analytes such as gastrin, some other polypeptide hormones such as vasoactive intestinal peptide require collection of blood in EDTA and prompt freezing of plasma to protect the analyte from metal oxidation. In addition to collection of blood in EDTA an addition of a proteolytic enzyme inhibitor such as aprotinin may be necessary to preserve labile polypeptide hormones such as ACTH, somatostatin etc. Analytes such as parathyroid hormone related protein (PTH-rp) are so labile that additives such as leupeptin and pepstatin have to be added to EDTA and aprotinin and the plasma refrigerated to achieve stability for up to 24 hrs. Catecholamines also require stabilization with additives such as EGTA and glutathione and prompt freezing of plasma at ?70°C. Special precautions are required in handling tumor tissue intended for hormone receptor measurements since they are not only extremely heat labile but are also subjected to alteration during specimen preparation.  相似文献   

17.
BackgroundAspartic proteases are a subfamily of endopeptidases that are useful in a variety of applications, especially in the food processing industry. Here we describe a novel aspartic protease that was purified from Peptidase R, a commercial protease preparation derived from Rhizopus oryzae.ResultsAn aspartic protease sourced from Peptidase R was purified to homogeneity by anion exchange chromatography followed by polishing with a hydrophobic interaction chromatography column, resulting in a 3.4-fold increase in specific activity (57.5 × 103 U/mg) and 58.8% recovery. The estimated molecular weight of the purified enzyme was 39 kDa. The N-terminal sequence of the purified protein exhibited 63–75% identity to rhizopuspepsins from various Rhizopus species. The enzyme exhibited maximal activity at 75°C in glycine–HCl buffer, pH 3.4 with casein as the substrate. The protease was stable at 35°C for 60 min and had an observed half-life of approximately 30 min at 45°C. Enzyme activity was not significantly inhibited by chelation with ethylenediamine tetraacetic acid (EDTA), and the addition of metal ions to EDTA-treated protease did not significantly change enzyme activity, indicating that proteolysis is not metal ion-dependent. The purified enzyme was completely inactivated by the aspartic protease inhibitor Pepstatin A.ConclusionBased on the observed enzyme activity, inhibition profile with Pepstatin A, and sequence similarity to other rhizopuspepsins, we have classified this enzyme as an aspartic protease.  相似文献   

18.
BackgroundLytic bacteriophages are bacterial viruses that upon infection kill their host cells and therefore have re-emerged as biological control agents of bacterial pathogens, particularly in the field of food related infections. Here, we investigated the stability in different food matrices of five phage isolates capable of controlling the foodborne pathogen Salmonella enterica serovar Enteritidis (SE).ResultsWe found that two phages, originally isolated from food sources, were up to 5 logs more stable than three phages isolated from sewage, in ten food matrices (fresh and processed) at both 4°C and 18°C.ConclusionLytic phages isolated from contaminated food sources seem to be a better choice when structuring phage cocktails to be used in the control of SE in food management protocols.  相似文献   

19.
Alpha2-macroglobulin (MG) levels in terms of proteinase binding capacity in fresh plasma of diabetics (males 183.9±60.3 mg MG/dl, females 173.8±49.7) and viral hepatitis patients (195.2±41.4) were comparable to normal sujbects (males 180.0±28.6, females 213.0±59.6) whereas in renal failure the values were decreased (144.0±30.0) and was found to be increased in nephrotic syndrome (331.5±47.9). MG activity was stable in normals and nephrotic patients in plasma on standing for 12 hr. at 37°C. In other conditions, the proteinase binding capacity was considerably reduced (mean decrease: 51.2% in diabetes, 64.0% in renal failure and 52.6% in viral hepatitis). Concentration of MG determined by immunoelectrophoresis did not however change in diabetic plasma on 12 hr. incubation. It is proposed that proteinases are continously generated in plasma in some disease conditions which bind to MG causing reduction in measured proteinase binding capacity.  相似文献   

20.
Human serum paraoxonase-1 (PON1), an enzyme on HDL prevents oxidation of LDL thereby preventing the development of atherosclerosis. Studies done so far have lead to conflicting results. As studies are lacking in North-West Indian Punjabi’s, a distinct ethnic group with high incidence of coronary artery disease, we determined PONase activity in this population. It has been postulated that sudden lowering of serum PONase may lead to precipitation of acute myocardial infarction. We determined serum PONase activity and lipids in 100 patients each of AMI (within 24 h of onset), stable CAD and 100 age and sex matched healthy controls. These were again determined after 6 weeks in AMI patients. The mean serum PONase activity was lowest in AMI patients (23.26 U/ml) followed by stable CAD patients (102.0 U/ml) where as in controls was highest (179.8 U/ml). In patients with AMI, activity was significantly higher at 6 weeks as compared to that after acute event (49.39 %; p < 0.05). Sudden lowering of serum PONase activity in a population which already has lower activity may be one of the risk factors for development of AMI.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号