浅谈多媒体作品开发中的关键技术——Alpha通道

Alpha通道实质上是8位灰度图像,用来存储图像文件中代表各像素点透明度的附加信息。在多媒体作品开发中,对对象的透明度的处理相对灵活而且重要,因此Alpha通道技术就成了其中的关键技术。本文主要阐述了Alpha通道在常用多媒体作品开发软件中具体的应用方法。     

Polymorphisms in genes involved in folate metabolism as maternal risk factors for Down syndrome in China

Objective: To explore the relationship between genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR), the central enzymes in folate metabolism that affects DNA methylation and synthesis, and the risk of Down syndrome in China. Methods: Genomic DNA was isolated from the peripheral lymphocytes of 64 mothers of children with Down syndrome and 70 age matched control subjects. Polymerase chain reaction and restriction fragment length polymorphism were used to examine the polymorphisms of MTHFR 677C→T, MTRR 66A→G and the relationship between these genotypes and the risk of Down syndrome was analyzed. Results: The results show that the MTHFR 677C→T polymorphism is more prevalent among mothers of children with Down syndrome than among control mothers, with an odds ratio of 3.78 (95% confidence interval (CI), 1.78～8.47). In addition, the homozygous MTRR 66A→G polymorphism was independently associated with a 5.2-fold increase in estimated risk (95% CI, 1.90～14.22). The combined presence of both polymorphisms was associated with a greater risk of Down syndrome than the presence of either alone, with an odds ratio of 6.0 (95% CI, 2.058～17.496).The two polymorphisms appear to act without a multiplicative interaction. Conclusion: MTHFR and MTRR gene mutation alleles are related to Down syndrome, and CT, TT and GG gene mutation types increase the risk of Down syndrome.     

Transient expression of chicken alpha interferon gene in lettuce

We investigated the possibility of producing chicken alpha interferon (ChIFN-α) in transgenic plants.The cDNA encoding ChIFN-a was introduced into lettuce (Lactuca sativa L.) plants by using an agro-infiltration transient expression system.The ChIFN-α gene was correctly transcribed and translated in the lettuce plants according to RT-PCR and ELISA assays.Re-combinant protein exhibited antiviral activity in vitro by inhibition of vesicular stomatitis virus (VSV) replication on chicken embryonic fibroblast (CEF).The results demonstrate that biologically active avian cytokine with potential pharmaceutical ap-plications could be expressed in transgenic lettuce plants and that it is possible to generate interferon protein in forage plants for preventing infectious diseases of poultry.     

高压氧对急性力竭性运动后血乳酸清除和肝酶谱恢复的影响

为了探讨HBO对力竭性运动后机体乳酸代谢和血清肝细胞酶的影响,让20名体育系男大学生在自行车功率计上运动至力竭,然后随机分成HBO组和对照组,他们分别在HBO和自然状态下恢复约120Min。在运动前、运动后和运动后2小时(恢复期)测定血清乳酸含量和LDB,ALAT、ALP、r-GT活力以及CG的含量。实验结果:力竭性运动后,HBO组和对照组血清LA的含量、LDH、ALAT、ALP、r-GT活力均显著升高,而血清CG含量却显著下降。恢复期,HBO组的LA含量显著低于运动后即刻(P<0.001)和运动前水平(F<0.01),并显著低于对照组(P<0.05)。恢复期与运动后比较,HBO组的血清LDH和r-GT活力均显著下降,而对照组虽有下降,但无显著性差异,虽然HBO组和对照组的ALAT活力均显著下降,但无显著性差异,虽然HBO组和对照组的ALAT活力均显著下降,但HBO组下降幅度比对照组大。实验结果提示:力竭性运动可引起机体肝细胞通透性的增加或损伤,HBO可以促进机体LA的清除和血清肝细胞酶的恢复,有利于运动疲劳的恢复。     

Studies on some serum enzyme levels in various liver diseases

Serum alkaline phosphatase (ALP) (EC 3.1.3.1), 5′nucleotidase (5′NT) (EC 3.1.3.5), aldolase (ALD) (EC 4.1.2.13) and sorbitol dehydrogenase (SDH) (EC 1.1.1.14) were estimated in infective hepatitis, alcoholic hepatitis, chronic active hepatitis, obstructive jaundice, cirrhosis of liver and amoebic liver abscess. It was observed that serum ALP and 5′NT were significantly increased in all cases of chronic active hepatitis and obstructive hepatic disease. However, the elevation observed in the latter was much higher than the former. Serum SDH and ALD levels were elevated in all cases of infective hepatitis, studied though increase in the former was much higher than the latter, suggesting its significance in the diagnostic confirmation of this disease. Results presented suggest 5′NT and SDH as more reliable diagnostic test compared to ALP and ALD for obstructive jaundice and infective hepatitis respectively.     

A rapid method for plasma ammonia estimation using an indigenously purified enzyme

Determination of ammonia level in blood is important, especially in the diagnosis of hepatic disorders. An indigenously purified enzyme was used in the standardisation of the assay. The assay is a two reagent system, requires five minutes for completion and can be performed at temperature between 25–27°C. Performance of the assay was assessed by linearity, imprecision, functional sensitivity and interference studies. Lyophilised reagent I and reagent II were found stable for at least one year. The plasma level of ammonia for the controls was 13.7±7.3 μMol/L, whereas for subjects of hepatic disorders, it was 69.1±32.4 μMol/L (P<0.001). The functional sensitivity was between 2–1000 μMol/L. Within-run coefficient of variation was between 1.1–2.0% and between-run coefficient of variation was between 1.9–3.7%. The mean recovery after dilution was 99.6%. The present method can estimate ammonia up to 1000 μMol/L without dilution of sample. Assay time of five minute may be shortened to one minute. This method is suited for routine clinical use in treatment of hepatic disorders.     

Reliability,Dimensionality, and Internal Consistency as Defined by Cronbach: Distinct Albeit Related Concepts

This article uses definitions provided by Cronbach in his seminal paper for coefficient α to show the concepts of reliability, dimensionality, and internal consistency are distinct but interrelated. The article begins with a critique of the definition of reliability and then explores mathematical properties of Cronbach's α. Internal consistency and dimensionality are then discussed as defined by Cronbach. Next, functional relationships are given that relate reliability, internal consistency, and dimensionality. The article ends with a demonstration of the utility of these concepts as defined. It is recommended that reliability, internal consistency, and dimensionality each be quantified with separate indices, but that their interrelatedness be recognized. High levels of unidimensionality and internal consistency are not necessary for reliability as measured by α nor, more importantly, for interpretability of test scores.     

Infliximab treatment in two Chinese patients with psoriatic arthritis

Psoriatic arthritis (PsA) is a rheumatoid factor (RF)-seronegative systemic inflammatory disorder associated with psoriasis. Current treatment for PsA in China is still focused on disease modifying anti-rheumatic drugs (DMARDs). In this paper, we report two Chinese patients with active longstanding PsA treated with infliximab, a human-mouse chimeric monoclonal antibody against tumor necrosis factor alpha (TNF-α). The results show that infliximab acted quickly and effectively in relieving peripheral and axial symptoms and refractory skin lesions, even in recombinant human TNF-α receptor (rhTNFR)-resistant case. The take-home message from our cases is that infliximab is a useful therapeutic option for refractory PsA, especially when a patient has a combination of psoriasis and psoriatic arthritis. Further local evidence and experience must be accumulated in order to make anti-TNF-α therapy more accessible to PsA patients in China.     

Investigation of the association between all-trans-retinol dehydrogenase (RDH8) polymorphisms and high myopia in Chinese

Retinoic acid level in the retina/choroid is altered in induced myopia models. All-trans-retinol dehydrogenase (RDH8) is an important enzyme of retinoic acid metabolism. This study aimed to investigate the association of the RDH8 gene with high myopia. Three single nucleotide polymorphisms (SNPs) [RDH851 (rs2233789), RDH8E5a (rs1644731), and RDH855b (rs3760753)] were selected, based on the linkage disequilibrium pattern of RDH8 from a previous study, and genotyped for 160 Han Chinese nuclear families with highly myopic (−10 diopters or worse) offspring as well as in an independent group with 166 highly myopic cases (−10 diopters or worse) and 211 controls. Family-based association analysis was performed using the family-based association test (FBAT) package, and genotype relative risk (GRR) was calculated using the GenAssoc program. Population-based association analysis was performed using Chi-square test. These SNPs were in linkage equilibrium with each other. SNPs RDH851 (rs2233789) and RDH8E5a (rs1644731) both did not show association with high myopia. SNP RDH855b (rs3760753) demonstrated significant association (P=0.0269) with a GRR of 0.543 (95% confidence interval=0.304–0.968, P=0.038). The association became statistically insignificant, however, after multiple comparison correction. Haplotype analysis did not show a significant association either. Population-based association analysis also showed no significant association (P>0.05). Our family- and population-based data both suggest that the RDH8 gene is unlikely to be associated with high myopia in Chinese.     

Association between 11beta-hydroxysteroid dehydrogenase type 1 gene polymorphisms and metabolic syndrome in Bosnian population

Introduction:

The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the conversion of the hormonally inactive cortisone to active cortisol, thus facilitating glucocorticoid receptor activation in target tissues. Increased expression of 11β-HSD1 in adipose tissue has been associated with obesity and insulin resistance. In this study, we investigated the association of two 11β-HSD1 gene (HSD11B1) polymorphisms with the metabolic syndrome (MetS) and its characteristics in the Bosnian population.

Materials and methods:

The study included 86 participants: 43 patients diagnosed with MetS and 43 healthy controls. Subjects were genotyped for two HSD11B1 gene polymorphisms: rs846910: G>A and rs45487298: insA, by the high resolution melting curve analysis. Genotype distribution and an influence of genotypes on clinical and biochemical parameters were assessed.

Results:

There was no significant difference in the mutated allele frequencies for the two HSD11B1 gene polymorphisms between MetS patients and controls. In MetS patients, no significant associations between disease-associated traits and rs45487298: insA were found. Regarding rs846910: G>A variant, heterozygous patients (G/A) had significantly lower systolic (P = 0.017) and diastolic blood pressure (P = 0.015), lower HOMA-IR index (P = 0.011) and higher LDL-cholesterol levels (P = 0.049), compared to the wild-type homozygotes. In the control group, rs45487298: insA polymorphism was associated with lower fasting plasma insulin levels (P = 0.041), lower homeostasis model assessment insulin resistance (HOMA-IR) index (P = 0.041) and lower diastolic blood pressure (P = 0.048). Significant differences between rs846910: G>A genotypes in controls were not detected. Haplotype analysis confirmed the association of rs45487298: insA with markers of insulin resistance in the control subjects.

Conclusions:

Our results indicate that a common rs45487298: insA polymorphism in HSD11B1 gene may have a protective effect against insulin resistance.