Membrane attack complex of complement and 20 kDa homologous restriction factor (CD59) in myocardial infarction

In order to investigate the mechanism of deposition of the complement membrane attack complex (MAC) in cardiomyocytes in areas of human myocardial infarction, the 20 kDA homologous restriction factor of complement (HRF20; CD59) and complement components (C1q, C3d and MAC) were analysed immunohistochemically using specific antibodies. Myocardial tissues obtained at autopsy from nine patients who died of acute myocardial infarction were fixed in acetone and embedded in paraffin. The ages of the infarcts ranged from about 3.5 h to 12 days. In cases of myocardial infarction of 20 h or less, MAC deposition was shown in the infarcted cardiomyocytes without loss of HRF20. Where the duration was 4 days or more, the cardiomyocytes with MAC deposition in the infarcted areas also showed complete loss of HRF20. Outside the infarcts, HRF20 in the cardiomyocytes was well preserved without MAC deposition. The present study suggests that the initial MAC deposition in dead cardiomyocytes can occur as a result of degradation of plasma-membrane by a mechanism independent of complement-mediated injury to the membrane. Loss of HRF20 from dead cardiomyocytes may not be the initial cause of MAC deposition, but may accelerate the deposition process of MAC in later stages of infarction.     

Conservation of genes encoding HLA-B5 and B35 cross-reactive group antigens in various races

HLA-B5 and B35 CREG antigens include HLA-B35, B51, B52, B53, and B78. Recent studies suggest that the genes encoding the HLA-B5, B35 CREG, and HLA-B58 antigens share a common ancestor. We sequenced the exons of the genes encoding HLA-B51, B53, and B58 from American black individuals and the gene HLA-B52 encoding from an Arabic individual, and compared them with previously reported sequences of HLA-B51 (B^*5101) and HLA-B52 (B^*5201) from Japanese, HLA-B53 (B^*5301) from an Algerian, and HLA-B58 (B^*5801) from a Sardinian. The sequences of the genes from the American black and Arabic individuals were identical to those from the other races. These findings support the hypothesis that these antigens have evolved prior to divergence of the major ethnic groups.     

Bloom''s syndrome with porokeratosis of Mibeili and multiple cancers of the skin, lung and colon

A 38-year-old Japanese male with Bloom's syndrome (BS) and porokeratosis of Mibelli (PM) developed multiple carcinomas of the skin and lung. There were multiple, spontaneous chromosomal aberrations and frequent sister chromatid exchanges (SCE). Cutaneous delayed-type hypersensitivity reactions were defective and serum IgM was decreased. The lung cancer was treated with radiation, which was effective but caused a severe pulmonary atelectasis and esophageal stricture. The patient expired one-and-a-half years later because of pneumonia. Autopsy disclosed an adenocarcinoma of the colon. The concurrent PM was considered responsible for the occurrence of multiple skin cancers.     

The expression of B7-H1 on keratinocytes in chronic inflammatory mucocutaneous disease and its regulatory role

PD-1 and its ligands, B7-H1/PD-L1 and B7-DC/PD-L2, have been identified recently as CD28-B7 family molecules that are implicated in immune regulation. Lichen planus (LP) is a T cell-mediated chronic inflammatory mucocutaneous disease. We investigated the expression and function of PD-1 and its two ligands in LP. Immunohistochemical examination revealed the abundant expression of PD-1 and B7-H1 in infiltrating T cells and macrophages, and lower-level expression of B7-DC on macrophages in the subepithelium. Interestingly, substantial expression of B7-H1 on keratinocytes (KCs) was found close to the numerous T cell infiltrates in the subepithelium. Unstimulated cultured KCs expressed both B7-H1 and B7-DC, and their expression was upregulated by proinflammatory cytokines, particularly IFN-gamma. The T-cell proliferative responses and IFN-gamma production that were induced by IFN-gamma-treated KCs were augmented preferentially by anti-B7-H1 mAb, but not by anti-B7-DC mAb. These results indicate the regulatory role of B7-H1 on KCs in the interactions with T cells. Our results suggest that the induction of B7-H1 on KCs may play an important role in tolerance induction in the inflamed oral mucosa and skin.     

Children with special needs in private day care centers

A study of 27 private day care centers showed that less than half enroll children with special needs and they represent only 1% of the current enrollment. Staff training and professional health consultation are both needed if more such children are to be mainstreamed in private day care centers.The authors would like to thank Laurie Rozet of the Santa Monica Child Care Resource and Referral Service and the day care center directors for their assistance in this study.     

Interaction of cyclosporin derivatives with the ATPase activity of human P-glycoprotein

1. P-glycoprotein, a 170–180 kDa membrane glycoprotein that mediates multidrug resistance, hydrolyses ATP to efflux a broad spectrum of hydrophobic agents. In this study, we analysed the effects of three MDR reversing agents, verapamil, cyclosporin A and [3′-keto-Bmt]-[Val^*]-cyclosporin (PSC 833), on the adenosine triphosphatase (ATPase) activity of human P-glycoprotein.
2. P-glycoprotein was immunoprecipitated with a monoclonal antibody (MRK-16) and the P-glycoprotein-MRK-16-Protein A-Sepharose complexes obtained were subjected to a coupled enzyme ATPase assay.
3. While verapamil activated the ATPase, the cyclosporin derivatives inhibited both the substrate-stimulated and the basal P-glycoprotein ATPase. No significant difference was observed between PSC 833 and cyclosporin A on the inhibition of basal P-glycoprotein ATPase activity. PSC 833 was more potent than cyclosporin A for the substrate-stimulated activity.
4. Kinetic analysis indicated a competitive inhibition of verapamil-stimulated ATPase by PSC 833.
5. The binding of 8-azido-[α-³²P]-ATP to P-glycoprotein was not altered by the cyclosporin derivatives, verapamil, vinblastine and doxorubicin, suggesting that the modulation by these agents of P-glycoprotein ATPase cannot be attributed to an effect on ATP binding to P-glycoprotein.
6. The interaction of the cyclosporin derivatives with ATPase of P-glycoprotein might present an alternative and/or additional mechanism of action for the modulation of P-glycoprotein function.

     

Prognostic values of serum CA19-9 and CEA levels for colorectal cancer

CA19-9 and CEA are associated with gastrointestinal malignancy as adhesion molecules. We measured serum CA19-9 and CEA levels in 328 patients with colorectal cancer. Both serum CA19-9 and CEA levels correlated significantly with recurrence and survival, respectively. Serum CA19-9 levels correlated significantly with survival according to Astler-Coller stage and multivariate analysis. Serum CEA levels showed no such correlations, although the combination of CEA with CA19-9 improved the sensitivity for predicting recurrence. Assessment of serum CA19-9 levels is more important than that of CEA in the clinical management of patients with colorectal cancer.     

Immunohistochemical Heterogeneity Within Clinically Nonfunctioning Pituitary Adenomas

To investigate whether adenohypophysial hormone expression is heterogeneous within individual clinically nonfunctioning pituitary adenomas, immunohistochemical examinations were performed on tissues obtained by multiple sampling of 11 adenomas. Stained sections were assessed by morphometric image analysis as well as semiquantitative estimation under microscopy. All tumors except one were immunopositive for one or more gonadotropins. Results were divided into five grades based on the proportion of immunoreactive cells per section. Semiquantitative estimation showed only a one-grade difference among samples from the same tumor in four cases for FSHβ and in two cases for LHβ. These qualitative similarities between multiple samples were confirmed by morphometric image analysis. From the practical standpoint of making a diagnosis of nonfunctioning pituitary adenoma, it is not necessary to take into account immunohistochemical heterogeneity within an individual tumor, and immunohistochemical findings in a given sample obtained at surgery can be regarded as representative of the entire adenoma.