单宁酸处理带瓣牛颈静脉的生物学评价

目的从生物学角度评价单宁酸处理的带瓣牛颈静脉是否符合国家医用材料的要求。方法带瓣牛颈静脉经单宁酸处理后按国家医用材料的要求进行浸提液的制备、细胞毒性试验、过敏试验、皮内刺激试验、原发性皮肤刺激试验、溶血试验、急性全身毒性试验及热原试验等生物学评价试验。试验方法均参照《医用有机硅材料生物学评价试验方法》GB／T16175-1996。结果培养的L-929小鼠成纤维细胞经含浸提液的培养基培养后形态良好，增值旺盛，材料细胞毒性评级为0～1。无皮肤刺激反应和过敏反应，皮内刺激试验PⅡ（原发性刺激指数）为0．4，和阴性对照组差异无统计学意义。全身毒性实验受试动物未出现毒性症状。溶血试验溶血率0．7％，符合国家标准（〈5％）。热原试验经中国药品生物制品检定所检定，单宁酸处理后带瓣牛颈静脉无热原（样品批号：060802017）。结论单宁酸处理的带瓣牛颈静脉符合国家医用材料的要求，可以植入人体。     

Safety evaluation of surgical materials by cytotoxicity testing

The cytotoxicity of three kinds of commercially available absorbable hemostats [oxidized cellulose (Surgicel, gauze and cotton types), microfibrillar collagen (Avitene), and cotton-type collagen (Integran)] and one adhesion barrier [sodium hyaluronate and carboxymethyl-cellulose membrane (Seprafilm)] were comparatively assessed by a colony assay using V79 cells and a minimum essential medium (MEM) elution assay in combination with a neutral red assay using L929 cells. Strong cytotoxicity was detected for Surgicel by both the MEM elution assay and the colony assay. For Avitene, both methods revealed weak cytotoxicity. For Seprafilm, no cytotoxicity was detected by the MEM elution assay, while a moderate degree of cytotoxicity was observed in the colony assay. For Integran cytotoxicity was not detected by either the MEM elution or the colony assay. The results of the different methods showed some inconsistency in terms of the degree of cytotoxicity of the materials. It is proposed that the combination of two or more sensitive cytotoxicity testing methods for the evaluation of biomaterials is necessary to avoid false-negative results for biomaterials at the preclinical stage. Furthermore, investigation of the correlation between the cytotoxicity and the extraction period of the surgical materials is helpful for predicting the effect of prolonged in vivo use of biomaterials on surrounding cells, tissues, and organs.     

Comparison of Quantiferon-TB Gold With Tuberculin Skin Test for Detecting Latent Tuberculosis Infection Prior to Liver Transplantation

Screening for latent tuberculosis infection (LTBI) is recommended prior to organ transplantation. The Quantiferon-TB Gold assay (QFT-G) may be more accurate than the tuberculin skin test (TST) in the detection of LTBI. We prospectively compared the results of QFT-G to TST in patients with chronic liver disease awaiting transplantation. Patients were screened for LTBI with both the QFT-G test and a TST. Concordance between test results and predictors of a discordant result were determined. Of the 153 evaluable patients, 37 (24.2%) had a positive TST and 34 (22.2%) had a positive QFT-G. Overall agreement between tests was 85.1% (kappa= 0.60, p < 0.0001). Discordant test results were seen in 12 TST positive/QFT-G negative patients and in 9 TST negative/QFT-G positive patients. Prior BCG vaccination was not associated with discordant test results. Twelve patients (7.8%), all with a negative TST, had an indeterminate result of the QFT-G and this was more likely in patients with a low lymphocyte count (p = 0.01) and a high MELD score (p = 0.001). In patients awaiting liver transplantation, both the TST and QFT-G were comparable for the diagnosis of LTBI with reasonable concordance between tests. Indeterminate QFT-G result was more likely in those with more advanced liver disease.     

Tape-stripping method in man: comparison of evaporimetric methods

BACKGROUND/PURPOSE: If the occlusion time of a closed chamber evaporimeter on the skin is too long, saturation might occur. We previously compared an open chamber and a closed chamber device on healthy volunteers. Comparable data on stripped skin with higher evaporation rates are not available. This study compares the sensitivity and correlation of open and closed chamber devices in a tape-stripping human model. The amount of tape removed SC was also quantified with a protein assay method. METHODS: Ten healthy volunteers (six male and four female; seven Caucasians and three Asian; mean age 38+/-16) were enrolled. In a randomized manner, one forearm was measured by an open chamber device and the opposite by a closed chamber device. After recording baseline measurements, 20 strippings were taken on each test site with tape disks. Transepidermal water loss (TEWL) was measured at the end of 10 and 20 tape strippings at each test site. Stratum corneum (SC) aggregates in the strips was assayed. RESULTS: The mean values obtained from two devices were similar after 10 trips and 20 strips. There was no statistically significant difference. The closed chamber device showed a slightly higher (but not significant) inter-individual coefficient of variation. SC aggregates in the strips were similar and without a statistically significant difference. CONCLUSION: The study suggests that both devices might yield similar TEWL values on stripped human skin in vivo.     

Characterization of Latent Transforming Growth Factor-β From Human Seminal Plasma

PROBLEM : Human seminal plasma is known to exhibit immunosuppressive activity. Transforming growth factor β (TGF-β) has been identified as an immunosuppressive factor in human seminal plasma. Biologically active TGF-β represents a family of 25-kDa homodimeric proteins linked with disulfide bonds. TGF-β associates with high molecular weight proteins noncovalently to form a type of latency that is biologically inactive. Quantitative distribution of active form of TGF-β versus inactive latent form of TGF-β, and mechanism of the TGF-β activation in human seminal plasma remain to be elucidated. PURPOSE : To characterize seminal plasma latent form of TGF-β, including its concentration, and the mechanism underlying the activation of TGF-β. METHOD : Gel filtrations on ACA-34 and Biogel P-60 were used to fractionate seminal plasma. TGF-β was measured by enzyme immunoassay using antibodies specific for TGF-β₁ and TGF-β₂, respectively. Radioreceptor assay with recombinant human [¹²⁵I]-TGF-β₁ was applied to qualitatively identify TGF-β₁. Kinetic experiments with various pH, temperature and time, along with protease inhibitors, were performed to delineate the activation mechanism of latent TGF-β. RESULTS : Human seminal plasma contained both TGF-β₁ and TGF-β₂, predominantly in latent form. The total concentration of TGF-β₁ averaged 238 ng/ml versus an average of 18 ng/ml for TGF-β₂. The in vitro activation or release of TGF-β₁, from latent TGF-β₁ was achieved only at acidic pH of <4.0, and was time and temperature dependent. At pH 3.7 and 37°C, a significant activation of latent TGF-β₁ was achieved after an incubation of only 15 min, reached the maximum at 120 min, and the activated TGF-β₁ remained relatively stable for at least 24 h. The activation was not inhibitable by a series of protease inhibitors examined, alone or in combination (e.g., phenylmethylsulfonyl fluoride, E-64, pepstatin, leupeptin, ethylenediamine tetraacetic acid). Competitive radioreceptor assay established the functional identity of TGF-β₁ in human seminal plasma with recombinant human TGF-β₁. CONCLUSION : Human seminal plasma TGF-β is biologically activated from high molecular weight latent TGF-β by acid pH. The acidic environment of female lower genital tract could represent an in vivo physiological condition for activation of seminal plasma TGF-β that may immunologically protect the integrity of sperm.     

Characteristics of antibody responses induced in mice by protein allergens

Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses.     

Genetic toxicology testing of Di(2-ethylhexyl) terephthalate

Di(2-ethylhexyl) terephthalate (DEHT) is a commercially produced chemical (Kodaflex® DOTP) that is used as a general purpose, low-volatility plasticizer for polyvinyl chloride and other polymeric materials. Less than 30 million kilograms of DEHT are produced annually. DEHT is isomeric with di(2-ethylhexyl) phthalate (DEHP), a nongenotoxic rodent carcinogen whose mode of action has been suggested to derive from its ability to produce hepatocellular proliferation and/or hepatic peroxisome proliferation. Thus it is important to know the behavior of DEHT in genotoxicity assays in order to compare it with that of DEHP and other phthalate ester plasticizers. It is known from previously published studies that rats fed DEHT in the diet at 2,000 mg/kg produce urine that is negative in the Ames Salmonella bacterial mutagenicity assay in the presence and absence of induced rat liver S-9 and in the presence and obsence of β-glucuronidase/aryl sulfatase. Reported here are the results of direct testing of DEHT in the Ames plate incorporation assay, the Chinese hamster ovary/hypoxanthine guanine phosphoribosyl transferase (CHO/HGPRT) in vitro mammalian cell mutagenicity assay, and an in vitro chromosome aberrations assay using CHO cells. The results for mono(ethylhexyl) terephthalate (MEHT), a metabolite of DEHT, in the Ames Salmonella bacterial mutagenicity assay are also presented. All test results for both DEHT and MEHT were found to be negative, and it is therefore concluded that DEHT, like its isomeric relative DEHP, is not genotoxic. © 1994 Wiley-Liss, Inc.     

C3d及荷C3d免疫复合物的测定与意义

用抗人Ｃ３和抗人ＩｇＧγ球蛋白组分作固相反应物，建立了检测补体活化片段Ｃ３ｄ及荷Ｃ３ｄ－ＩＣ的ＥＬＩＳＡ法，并对临床各类疾病患者血清Ｃ３ｄ和Ｃ３ｄ－ＩＣ的水平进行了测定，结果表明：慢性肾炎，ＳＬＥ，慢性乙肝及肺炎患者血清Ｃ３ｄ总体水平均较对照组显著增高，分别有５８．５％～７２．２％的病人Ｃ３ｄ含量高于正常上限（Ｐ〈０．０１），且该类病人亦有较高的Ｃ３ｄ－ＩＣ阳性检出率（肺炎患者例外）本项研究中，Ｃ     

MTT法检测雷公藤内酯醇对晶状体上皮细胞增殖的影晌

目的:研究雷公藤内酯醇对体外培养的牛晶状体上皮细胞增殖的抑制作用。方法:取第4代对数生长期的牛晶状体上皮细胞培养24h后,加入重组人表皮生长因子(终浓度50μg/L)和不同浓度的雷公藤内酯醇(40,20,10μg/L),分别作用6,12,24,48,72h后,采用MTT法观察雷公藤内酯醇对牛晶状体上皮细胞增殖的影响。结果:不同浓度的雷公藤内酯醇,于不同时间作用在处于增殖状态的LECs,其增殖抑制率升高呈现明显的时间及剂量依赖性。结论:雷公藤内酯醇对晶状体上皮细胞增殖有明显的抑制作用在防止后囊混浊方面有广阔的前景。