Chain length heterogeneity of nucleosomal DNA in mouse liver after dimethylnitrosamine administration

The effect of dimethylnitrosamine on the nucleosomal structure of mouse liver chromatin was studied. After a single oral dose of dimethylnitrosamine (2–75 mg/kg body weight 45 min before sacrifice) liver nuclei were isolated and incubated with micrococcus nuclease. Nucleosomes were separated on sucrose density gradients. There were no differences in nucleosomal sedimentation velocities between preparations from control and dimethylnitrosamine treated animals. The supernatant obtained after centrifugation of the lysed nuclei (2 min at 4,000 g _av) and nucleosomal peak fractions were used for isolation of DNA. DNA was heat denatured in 7 M urea or formamide. After electrophoresis on polyacrylamide gels areas under mononucleosomal DNA and smaller fragments were measured and compared with the total DNA area. The increase in DNA fragmentation was dimethylnitrosamine dose response dependent. When expressed as per cent of controls it amounted to 106% for 2 mg; 115% for 10 mg; 127% for 25 mg; 164% for 75 mg dimethylnitrosamine/kg body weight. A good correlation between mobility and log of chain length of 174 RF DNA-Hae III digest was obtained in nondenaturing 5% polyacrylamide gels and denaturing non-aqueous formamide polyacrylamide gels but not in 12% polyacrylamide gels containing 7 M urea. DNA of mononucleosomal peak fractions contained 200 and that of dinucleosomal peak fractions 400 nucleotides. Fragmentation of DNA was closely related to in vivo dimethylnitrosamine treatment but was not detected in measurements of protein-DNA complexes in the chromatin. It was disclosed on denaturation of DNA followed by polyacrylamide gel electrophoresis.Abbreviations DMN dimethylnitrosamine - SDS sodium dodecyl sulfate The work was supported by Grant Number 1 R0 1 CA26642-01, awarded to A.v.d.D. by the National Cancer Institute, DHEW     

盐酸达克罗宁凝胶的制备

目的：制备盐酸达克罗宁凝胶。方法：用CMC-Na作基质，制备盐酸达克罗宁凝胶，并建立质控方法。结果：处方设计合理，制备工艺可行，平均回收率为100．4％。RSD=O．8％。结论：该凝胶剂质量稳定可靠，可满足临床使用。     

Utility of peptide–protein affinity complexes in proteomics: identification of interaction partners of a tumor suppressor peptide*

Abstract: We used a N‐biotinylated peptide analog of the C‐terminal domain of the tumor suppressor protein, p21^cip1/waf1 to elucidate peptide/protein interacting partners. The C‐terminal domain of p21^cip1/waf1 protein spanning 141–160 amino acid residues is known to bind PCNA and this interaction is important in many biological processes including cell‐cycle control. This C‐terminal 20‐mer efficiently extracts PCNA in the presence of a variety of N‐ or C‐terminally attached affinity tags. Using difference silver stained 2D gels combined with in‐gel tryptic digests, we identified the difference spots using MALDI‐TOF mass spectrometry‐based peptide mass fingerprinting followed by a database search using profound against NCBIs human nonredundant protein sequence data bank. Identified spots include the p48 subunit of chromatin assembly factor‐1, the heat shock 70 protein analog BiP, calmodulin, nucleolin and a spot similar in size to dimeric PCNA. In contrast, microcapillary ion‐trap LC‐MS/MS analysis of a tryptic digest of entire affinity extracts derived from both control and experimental runs followed by database searches using sequest confirmed the presence of most of the above proteins. This strategy also identified hnRNPA1, HPSP90α, HSP40 and T‐complex protein 1, a protein similar to prothymosin, and a possible allelic variant of the p21^cip1/waf1 protein. The use of N‐biotinylated peptide derived from the C‐terminal domain of p21^cip1/waf1 protein in proteomic analysis exemplified here suggests that peptides obtained from intracellular functional screens could also potentially serve as efficient baits to discover new drug targets.     

Molecular epidemiological evidence for ascending urethral infection in acute bacterial prostatitis

PURPOSE: To test the ascending urethral infection in the pathogenesis of acute bacterial prostatitis, we assessed the clonality of Escherichia coli strains isolated from urine and rectal swab of patients with acute bacterial prostatitis using molecular typing methods. MATERIALS AND METHODS: A total of 50 E. coli strains each isolated from urine and rectal swabs of 9 men with acute bacterial prostatitis at diagnosis were examined for 6 urovirulence determinant profiles and pulsed field gel electrophoresis patterns. In 1 case E. coli isolates from the rectal swab of the patient's wife were also examined at diagnosis and after 5 weeks. RESULTS: The urovirulence profile and pulsed field gel electrophoresis demonstrated that causative E. coli was monoclonal in each case, and present in the rectal swab as a predominant (96% to 100%) fecal clone in 2 and a minority clone (2% to 8%) in 4. Furthermore, causative E. coli dominated in the rectal swab of the 1 patient's wife. CONCLUSIONS: Our results are consistent with the ascending route of infection in acute bacterial prostatitis. However, causative E. coli might possibly originate from either intestinal reservoir of the host or household member. Owing to limitations of the cross-sectional design of this study, longitudinal studies are necessary to establish the ascending route of infection in this disease.     

唯地息眼凝胶剂治疗兔芥子气角膜损伤

目的:观察唯地息眼凝胶剂对兔芥子气角膜上皮损伤的治疗作用。方法:新西兰白兔8只,用200μL/L液态芥子气致伤双眼角膜5min,左眼为治疗组,用唯地息眼凝胶剂点眼,4次/d,右眼为对照组,用2.5g/L氯霉素眼液滴眼,4次/d,分别于染毒后2,8,16,24,36,48和72h对角膜荧光素着色区拍照,计算其上皮愈合速率和上皮破损率。结果:治疗组和对照组的角膜上皮愈合速率分别为(1.15±0.19)mm2/h和(1.03±0.12)mm2/h,两者有显著差异(P<0.05),角膜上皮破损率分别为44.4%和54.2%,两者差异显著(P<0.05)。结论:唯地息眼凝胶剂能促进芥子气染毒引起的兔眼角膜损伤的上皮愈合,也能减少角膜上皮反复破损。     

应用微柱凝胶法鉴定婴儿ABO及Rh（D）血型

目的 :比较传统试管法和微柱凝胶法全自动血型系统鉴定婴儿ABO及Rh(D)血型的研究。方法 :选取500份婴儿脐带血标本 ,采用试管法和微柱凝胶法进行ABO和Rh(D)血型 ,并选项取40份抗原性减弱的标本采用两种方法比较。结果 :在鉴定婴儿ABO和Rh(D)血型时两种方法差异无显著性。结论 :微柱凝胶法可取代试管法用于婴儿的ABO和Rh(D)血型鉴定。     

可生物降解的聚乳酸羟基乙酸牙周缓释凝胶的研究

目的采用聚乳酸羟基乙酸(PLGA)研制替硝唑牙周缓释凝胶。方法根据聚合物的分子量、浓度、载药量和增塑剂等因素来优选最佳配方。结果聚合物溶液中N-甲基-2-吡咯烷酮(NMP)P、EG400、PLGA(75∶25)的最佳比例为65∶5∶30,5%替硝唑与聚合物溶液均匀混合即得凝胶。凝胶必须在室温下避光保存。结论该凝胶缓释时间长达7d,用于牙周炎的治疗有效。     

凝胶材料配比对丁香罗勒油透皮凝胶体外透皮性能的影响

目的:探索凝胶材料配比对丁香罗勒油透皮凝胶体外透皮性能的影响。方法:以CMC-Na和PVA为辅料,制备丁香罗勒油透皮剂。采用改良Franz扩散池,以鼠背皮肤为屏障进行经皮渗透试验,以丁香酚含量为指标,通过气相色谱法检测丁香罗勒油的经皮渗透量。结果:CMC-Na和PVA总量对丁香罗勒油透皮能力有较大影响,以25%为最佳;CMC-Na和PVA的比例对丁香罗勒油透皮能力无影响,最佳比例4∶2。结论:丁香罗勒油透皮凝胶可极大地提高丁香罗勒油的药效。