Endothelial cell antigens recognized by xenoreactive human natural antibodies.

Hyperacute rejection of vascularized, discordant xenografts is generally though to be initiated when natural antibodies of the recipient bind to endothelial cells of the donor organ. While rejection of such xenografts always occurs, the molecular targets of natural antibodies have not been elucidated. The aim of the experiments reported herein was to identify the molecules on porcine endothelial cells that would be recognized by human natural antibodies if a porcine organ were to be transplanted into a human (or rhesus). Toward the end, it was shown that the major components recognized by human serum on porcine endothelial cells are glycoproteins of 115kDa, 125kDa, and 135kDa (gp115/135). Reactivity with these glycoproteins was abrogated by enzymatic cleavage of N-linked oligosaccharides or of subterminal beta-D-gal residues suggesting that the determinants are located on oligosaccharides rather than on the polypeptide cores. The biological relevance of gp115/135 was suggested by experiments in which a similar series of components was shown to be recognized by rhesus natural antibodies and by the absorption of such antibodies by perfusion of porcine kidneys. The gp115/135 antigens were present on porcine platelets but not porcine RBC or lymphocytes. Nevertheless, purified RBC and lymphocytes absorbed human anti-gp115/135, suggesting that human natural antibodies recognize the same or crossreactive carbohydrate determinants expressed on the surface of a variety of cells.     

Sinusoidal heart rate pattern and face presentation in a fetus from a postterm pregnancy. A case report

A case of sinusoidal fetal heart rate pattern occurred in association with postdate pregnancy and face presentation. The case met the criteria for sinusoidal pattern established by Modanlou and Freeman except for a prior period of reactivity. Prompt recognition and action precluded the potential adverse outcome associated with this tracing.     

Does short term placebo treatment of chronic schizophrenia produce long term harm?

A randomised double blind placebo controlled trial is the most reliable method of assessing putative new developments in medical treatment. In schizophrenia, however, some clinicians believe that relapse contributes to long term deterioration and therefore that patients exposed to either placebo or an inactive new treatment may be put at a disadvantage in the long run if the trial leads to an additional relapse. A seven year follow up of patients included in a randomised placebo controlled trial of fluphenazine decanoate, in which 66% of the group given placebo relapsed compared with 8% of those who received the active drug, permitted examination of any long term adverse consequences in those patients who had received placebo. Seventy six (94%) of the 81 patients in the original trial were followed up. At the end of the follow up period there were no consistent or important differences in any measure of clinical or social outcome between the patients who had received placebo and those who had received the active drug. This negative finding has implications for the debate on the risk of placebo controlled trials of maintenance treatment in chronic schizophrenia.     

硫酸多糖对体外人脐静脉内皮细胞损伤的保护作用

研究表明,硫酸多糖体外对多聚阳离子和氧自由基损伤的人脐静脉内皮细胞有保护作用。肝素、硫酸软骨素A抗多聚阳离子损伤作用比同浓度低分子肝素和甘糖酯强。肝素、硫酸软骨素A、甘糖酯抗氧自由基损伤作用优于同浓度低分子肝素。结果显示硫酸多糖有保护血管内皮的作用,其作用可能与所带阴离子基团有关。     

Rates of Borrelia burgdorferi infection in Ixodes dammini (Acari: Ixodidae) in southwestern Wisconsin.

Ixodes dammini Spielman, Clifford, Piesman & Corwin collected from a study site in southwestern Wisconsin were examined for Borrelia burgdorferi infection. Adult spirochete infection rates varied seasonally (38.1%, spring 1990; 60.3%, fall 1990; 41.2%, spring 1991) and were similar to or higher than rates reported in various studies from the northeastern United States. Statistical comparison of seasonal infection rates indicated a significant difference between the fall 1990 adult population and the subsequent overwintered population of the same cohort (spring 1991). Additionally, a significant decrease in the intensity of spirochete infection was observed in the overwintered adult sample.     

Restriction enzyme fingerprinting of enterobacterial plasmids: a simple strategy with wide application

Restriction enzyme fingerprints were generated from purified plasmid DNA from 324 clinical isolates that belonged to 7 enterobacterial genera and 88 single plasmids in Escherichia coli K 12 according to the following strategy. Purified plasmid DNA was digested with PstI. The number of fragments detected in a 0.8 agarose gel was used to determine which 2 of 6 restriction enzymes including PstI was most likely to provide a fingerprint comprising sufficient fragments to ensure specificity but sufficiently few to allow easy visual assessment and minimize coincidental matching. When PstI produced greater than 20 fragments, EcoRI and HindIII were used; when PstI generated less than 6 fragments Bsp 1286 and AvaII were used and SmaI was employed when between 6 and 20 fragments were obtained from PstI digests. Using a minimum of 12 fragments from a combination of 2 enzymes as the criterion for characterizing a strain/plasmid, satisfactory 2-enzyme fingerprints were obtained from 87% of the strains and plasmids studied using PstI and no more than two additional enzymes per strain. Of the remaining 54 strains, 51 harboured only small plasmids (less than 10 kb) and 3 produced satisfactory fingerprints when digested with a fourth enzyme.     

Direct effects of endotoxin on hepatocytes. Synthesis of a specific secretory protein

The synthesis of acute-phase proteins by the liver during sepsis has been thought to be induced primarily by monokines released from activated macrophages, although glucocorticoid hormones may also stimulate this process to a lesser degree. According to this concept, synthesis of these proteins following administration of bacterial endotoxins would be an indirect effect and would not reflect a direct interaction of the endotoxin molecule with the hepatic parenchymal cell. We observed, however, that the synthesis of a 23-kilodalton protein was stimulated directly by the addition of lipopolysaccharide to cultures of primary mouse hepatocytes. The synthesis of this protein was also stimulated by glucocorticoids and interleukin 1. These findings demonstrate that certain hepatic proteins are subject to complex regulation by several factors thought to be important mediators of sepsis; in addition, they suggest that hepatic parenchymal cells may have the intrinsic capacity to respond directly to bacterial endotoxins.     

Does previous infection protect against atopic eczema and recurrent wheeze ininfancy?

BACKGROUND: Frequent infection in infancy and early childhood has been hypothesized to explain the low prevalence of asthma and other atopic disease among children in developing countries (the so-called 'hygiene hypothesis'), but the low prevalence in Eastern Europe remains unexplained. OBJECTIVE: To test the hygiene hypothesis in the Republic of Belarus by examining the relationship between gastrointestinal (GI) and respiratory infection and two potentially atopic outcomes in the first 12 months of life: atopic eczema and recurrent wheeze. METHODS; We carried out two case-control studies nested within a large (n=17 046) randomized trial in Belarus, with cases defined as (1) first occurrence of atopic eczema (n=819) and (2) second episode of wheezing (n=112). Incidence density sampling was used to select four matched controls born within 1 month at the same hospital as the case. Exposure was defined as one or more episodes of GI or respiratory infection (examined separately) with onset >7 days before onset of the case's atopic outcome. Analyses controlled for family atopic history, duration of exclusive breastfeeding, sex, birth weight, maternal education, and (for recurrent wheeze) maternal smoking. RESULTS: For atopic eczema, prior GI infection occurred in 7.4% of cases vs. 6.0% of controls [adjusted OR=1.27 (0.94-1.72)] and prior respiratory infection in 35.2% vs. 32.6% [adjusted OR=1.14 (95% CI=0.94-1.37)]. For recurrent wheeze, prior GI infection occurred in 9.8% of cases vs. 7.4% of controls [adjusted OR=1.30 (0.60-2.82)]. CONCLUSION: Our results do not support the hypothesis that infection protects against atopic eczema or recurrent wheezing in the first 12 months of life.