冠心病患者血液流变学和氧化低密度脂蛋白变化及其相关性分析

目的 :观察冠心病患者血液流变学、氧化低密度脂蛋白、氧自由基变化及其相关性。方法 :择期开腹手术患者64例 ,冠心病组和对照组各 3 2例 ,同时监测血液流变学的变化、氧化低密度脂蛋白 （ox-L DL ）、脂质过氧化物（L PO）和超氧化物歧化酶 （SOD）等指标。结果 :冠心病组全血高切黏度、低切黏度、红血细胞压积、红细胞变形指数和 ox-L DL,均显著高于对照组 （P<0 .0 5或 P<0 .0 1） ;且全血高切黏度、低切黏度及红血细胞压积与 ox-L DL 间呈显著正相关 （P<0 .0 5） ;与对照组相比 ,冠心病组 L PO活性增高 （P<0 .0 5） ,SOD活性降低 （P<0 .0 5）。结论 :冠心病患者在血液流变学异常变化的同时 ,伴有 ox-L DL 和 L PO活性增高 ,SOD活性降低 ,且血液流变学变化与 ox-L DL间呈正相关     

6种抗菌中药对鼠疫菌抑菌作用观察

目的 观察6种抗菌中药对鼠疫菌的抑菌活性作用.方法 选择6种(黄连、苦参、连翘、大黄、生地、知母)常用抗菌中药,分别采用水提法制备至质量浓度1 mg/L的药液.应用液体稀释法测定上述中药对鼠疫菌201株与EV76株的最低抑菌浓度(MIC).结果 黄连、大黄与连翘抑制鼠疫菌的作用均较强,MIC值均≤0.050 00 mg/L,其中大黄的抑菌作用最强(MIC值为0/025 00 mg/L).同一种中药对鼠疫菌不同菌株的MIC值相同.结论 常用抗菌中药对鼠疫菌有一定的抑菌作用.     

Identification of a plant serine-arginine-rich protein similar to the mammalian splicing factor SF2/ASF.

We show that the higher plant Arabidopsis thaliana has a serine-arginine-rich (SR) protein family whose members contain a phosphoepitope shared by the animal SR family of splicing factors. In addition, we report the cloning and characterization of a cDNA encoding a higher-plant SR protein from Arabidopsis, SR1, which has striking sequence and structural homology to the human splicing factor SF2/ASF. Similar to SF2/ASF, the plant SR1 protein promotes splice site switching in mammalian nuclear extracts. A novel feature of the Arabidopsis SR protein is a C-terminal domain containing a high concentration of proline, serine, and lysine residues (PSK domain), a composition reminiscent of histones. This domain includes a putative phosphorylation site for the mitotic kinase cyclin/p34cdc2.     

Molecular systematics of higher primates: genealogical relations and classification

We obtained 5' and 3' flanking sequences (5.4 kilobase pairs) from the psi eta-globin gene region of the rhesus macaque (Macaca mulatta) and combined them with available nucleotide data. The completed sequence, representing 10.8 kilobase pairs of contiguous noncoding DNA, was compared to the same orthologous regions available for human (Homo sapiens, as represented by five different alleles), common chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), and orangutan (Pongo pygmaeus). The nucleotide sequence for Macaca mulatta provided the outgroup perspective needed to evaluate better the relationships of humans and great apes. Pairwise comparisons and parsimony analysis of these orthologues clearly demonstrated (i) that humans and great apes share a high degree of genetic similarity and (ii) that humans, chimpanzees, and gorillas form a natural monophyletic group. These conclusions strongly favor a genealogical classification for higher primates consisting of a single family (Hominidae) with two subfamilies (Homininae for Homo, Pan, and Gorilla and Ponginae for Pongo).     

A fidelity assay using "dideoxy" DNA sequencing: a measurement of sequence dependence and frequency of forming 5-bromouracil X guanine base mispairs.

DNA replication fidelity has been assayed by using a modified DNA sequencing reaction. In one experimental approach, dideoxycytidine 5'-triphosphate (ddCTP) was used as a chain terminator during replication of M13 phage DNA by the large fragment of DNA polymerase I. The deoxyribonucleotide analogue BrdUTP was used to compete against ddCTP-induced chain terminations as an assay for B X G base mispairing (B represents bromodeoxyuridine when the analogue is present as a base pair or base mispair). By comparing BrdUTP to dCTP for competition against ddCTP, an average misincorporation frequency for BrdUMP of 0.2% was found. A similar average misincorporation frequency has been measured previously for the incorporation of radioactively labeled BrdUMP and dCMP into the synthetic template-primer poly-[d(G,T)] X oligo(dA). The advantage of the sequencing method is that an error frequency is determined for each template guanine in a defined DNA sequence, thus providing information on the effect of neighboring base sequences on fidelity. Misincorporation frequencies varied no more than 5-fold among 50 template guanines tested. The approach used here is not limited for use with nucleotide analogues but is generally applicable in determining misincorporation frequencies and sequence specificities for any deoxynucleoside triphosphate substrate. In a second experimental approach, base mispairing between bromouracil and guanine was demonstrated directly by using 5-bromodideoxyuridine 5'-triphosphate (BrddUTP). A comparison of chain terminations attributable to BrddUTP and to dideoxythymidine 5'-triphosphate (ddTTP) revealed that B X A and T X A base pairs formed at about the same rate, whereas B X G mispairs occurred 4-10 times more frequently than T X G. The elevation in the frequency of B X G over T X G mispairs is consistent with the mutagenic behavior of the base analogue.     

Inactivation of purified human alpha 2-antiplasmin and purified human C1 inhibitor by synthetic fibrinolytic agents

3-Hydroxypropyl flufenamide (Flu-HPA) is one of a series of flufenamic acid derivatives that enhances blood clot lysis in vitro. Studies of possible mechanisms of action of Flu-HPA were undertaken. The profibrinolytic activity of Flu-HPA in clot lysis assays was found to be dependent on plasminogen. The influence of Flu-HPA on the ability of purified alpha 2-antiplasmin to inhibit purified plasmin was studied. Plasmin activity was determined using 125I-fibrin plates or the spectrophotometric tripeptide substrate, Val-Leu-Lys-paranitroanilide. At Flu-HPA concentrations greater than 1 mM, the inhibitory activity of alpha 2-antiplasmin was abolished in a time-dependent and concentration- dependent manner. The influence of Flu-HPA on the ability of purified Cl inhibitor to inhibit purified plasma kallikrein and beta-Factor XIIa was also studied. Cl inhibitor activity was abolished by Flu-HPA at concentrations greater than 2 mM. Notably, Flu-HPA up to 60 mM did not affect the amidolytic activities of plasmin, kallikrein, or beta-Factor XIIa. Flu-HPA did not release enzyme activity from preformed complexes of either alpha 2-antiplasmin and plasmin of Cl inhibitor and kallikrein. A water-soluble derivative of flufenamic acid, N-flufenamyl- glutamic acid, also inactivated alpha 2-antiplasm and Cl inhibitor. This inactivation was shown to be reversible. These results indicate that synthetic fibrinolytic compounds such as flufenamic acid derivatives may promote fibrinolysis by directly inactivating alpha 2- antiplasmin and Cl inhibitor.     

Influence of systemic inflammatory response syndrome and sepsis on outcome of critically ill infected patients

The clinical significance of the systemic inflammatory response in infected patients remains unclear. We examined risk factors for hospital mortality in 3,608 intensive care unit patients included in the European Sepsis Study. Patients were categorized as having infection without or with (i.e., sepsis) systemic inflammatory response, severe sepsis, and septic shock, on the first day of infection. Hospital mortality varied from 25 to 60% according to sepsis stage, but did not differ between the first two categories (hazard ratio, 0.94; p = 0.55), whereas there was a grading of severity from sepsis to severe sepsis (1.53, p < 10-4) and septic shock (2.64, p < 10-4). Within each stage, mortality was unaffected by the number of inflammatory response criteria. Prognostic factors identified by Cox regression included comorbid conditions, severity of acute illness and acute organ dysfunction, shock, nosocomial infection, and infection caused by aerobic gram-negative bacilli, enterobacteria, Staphylococcus aureus, and infection from a digestive or unknown source. We conclude that whereas the categorization of infection by the presence of organ dysfunction or shock has strong prognostic significance, infection and sepsis have similar outcomes, unaffected by the presence or number of inflammatory response criteria. Refinement of risk stratification of patients presenting with infection and no organ dysfunction is needed.     

The etiology of community-acquired pneumonia at an urban public hospital: influence of human immunodeficiency virus infection and initial severity of illness.

In a prospective study, the etiology of community-acquired pneumonia (CAP) was investigated among consecutive patients admitted to an academic, urban public hospital in Seattle. The study population was uniquely young, was predominantly male, and had high rates of homelessness, cigarette smoking, alcoholism, injection drug use, and human immunodeficiency virus (HIV) infection. Leading causes of CAP among HIV-negative patients were aspiration, followed by Streptococcus pneumoniae, Legionella species, and Mycoplasma pneumoniae. Among HIV-positive patients, Pneumocystis carinii, Mycobacterium tuberculosis, S. pneumoniae, and M. pneumoniae were the most common etiologic agents. Severe CAP was associated with typical bacterial infections and aspiration pneumonia but not Legionella infection among HIV-negative patients and with Pseudomonas aeruginosa infections among HIV-positive patients. These findings emphasize the need to tailor empirical antibiotic therapy according to local patient populations and individual risk factors and highlight the importance of recognizing underlying HIV infection in patients who are hospitalized with CAP.     

慢性乙型肝炎患者血清抗HP体检测及其与年龄变化、病毒载量和病毒基因型的关系分析

目的 探讨幽门螺杆菌(HP)在慢性乙型肝炎中的作用.方法 采用病例对照研究的方法分析376例慢性乙型病毒性肝炎患者的HP感染状况与年龄、乙型肝炎病毒(HBV)DNA定量和分型的关系.结果 HP感染率随年龄变化无明显差异(P＞0.05),HP感染率在慢性乙型肝炎组(56.2%)、乙型肝炎肝硬化组(69.9%)、乙型肝炎合并肝癌组(75.0%)明显高于健康对照组(43.4%)(P＜0.01),各组与慢性胃炎组(57.9%)相比较无明显差异(P＞0.05),其中肝硬化组和合并肝癌组HP感染率均高于肝炎组(P＜0.05).不同病毒载量慢性乙型肝炎患者的HP感染率均明显高于健康对照组(P＜0.01),但不同病毒载量之间无明显差异(P＞0.05).慢性乙型肝炎患者B基因型、C基因型和D基因型HP感染率分别为61.3%、63.3%和50.0%,三组之间比较无统计学意义(P＞0.05).结论 慢性乙型肝炎患者HP感染率明显增加,且HP感染率随着肝病病变程度的进展而增加.     

Effect of 3'' flanking neighbors on kinetics of pairing of dCTP or dTTP opposite O6-methylguanine in a defined primed oligonucleotide when Escherichia coli DNA polymerase I is used.

O6-Methylguanine (m6G) was incorporated site-specifically into two 25-base oligonucleotides differing only in the nucleotide on the 3' side of the modified base. Templates were primed with oligonucleotides terminating one or two bases prior to the site at which incorporation kinetics were to be investigated. Escherichia coli DNA polymerase I (Klenow fragment) was used to determine the apparent Km and relative Vmax of incorporation of either dCTP or dTTP opposite m6G or G. These data were used to calculate the relative frequency of incorporation opposite the m6G or the unmodified G. When the sequence was 3'-Cm6G-5', there was a 6- to 7-fold preference for formation of a m6G.T pair compared with m6G.C. The m6G.T frequency, based on Vmax/Km, was at least 50-fold greater than that of a G.T pair at the same site. Changing the sequence to 3'-Tm6G-5' had a marked effect on both Km and Vmax of pairs containing m6G and on the incorporation frequency of T opposite m6G, which was then only slightly favored over m6G.C. When replication was started directly opposite m6G, the kinetics appeared unaffected. These data indicate that the frequency of incorporation of C or T opposite m6G in a DNA template is dependent on the flanking neighbors and that a change of even a single base at the 3' position can have a major effect on mutagenic efficiency. Replication using Drosophila Pol alpha gave the same values for relative frequencies. Pairing of either C or T with m6G on the primer terminus did not significantly inhibit extension of the next normal base pair, in contrast to terminal mismatches of unmodified bases. It is concluded that, in the absence of repair, m6G can exhibit widely differing mutation frequencies which, in these experiments, can be as high as 85% of the replicated base. This variation in frequency of changed pairing could contribute to the occurrence of mutational "'hot spots" after replication of damaged DNA.