Human heat shock protein 60 (409-424) fragment is recognized by serum antibodies of patients with acute coronary syndromes.

Acute coronary syndromes (ACS), including unstable angina (UA) and acute myocardial infarction (MI), are clinical manifestations of a progressive atherosclerotic process. Antibodies (Ab) to heat shock proteins (hsp) have been reported to be associated with atherosclerosis. Blood samples from 35 patients with ACS and 20 healthy volunteers were tested for Ab to human hsp60 by an enzyme-linked immunosorbent assay (ELISA). Levels of specific serum Ab against hsp60 were significantly elevated in patients with ACS when compared to clinically healthy subjects. To determine the antigenic determinants recognized by these Ab, antibody binding to seven peptides, selected from the hydrophilic and acrophilic regions of the human hsp60 molecule, was assessed. Despite the individual variation in the immune response among patients, one immunodominant region was revealed corresponding to the hsp60 (409-424) peptide. The identification of this epitope may be important for understanding the function of this protein in the atherosclerotic process.     

Clear cell chondrosarcoma: case report and ultrastructural study

A case of clear cell chondrosarcoma in a Chinese patient is described. The clear cells showed strongly positive S-100 protein immunoreactivity. Ultrastructurally 2 types of chondroid cells were demonstrated. One type appeared more primitive with abundant electron-lucent cytoplasm and sparse organelles. The other type of cell was more differentiated with presence of microvilli and numerous dilated cisternae of endoplasmic reticulum. Previous ultrastructural studies on these lesions were reviewed and compared with the present findings.     

Effects of social rearing conditions on conditioned suppression in rats

Twenty-two rats were reared in standard conditions during the first two months of their life. Then the animals were divided into two groups exposed to different rearing conditions. Twelve animals (Group SO) were housed socially, six animals per cage, and for three weeks they were subjected to sensory stimulation in an enriched environment. The other ten subjects were kept individually (Group IN); one rat per mesh cage, in conditions of relatively impoverished sensory stimulation. In both groups the training of the conditioned emotional response (CER) was performed when animals were three months old. In contrast to IN subjects, the rats subjected to permanent social contacts and reared in the enriched environment (Group SO) revealed almost equally low instrumental response rates in trials with the conditioned stimulus (CS) paired with nociceptive foot-shock (US), and in periods when no CS and/or US were applied. The results suggested that early exposure to an enriched environment caused a later decrease of the animals' capability to differentiate between the aversive CS and cues of the experimental context. This cognitive impairment was probably a secondary effect of fear generalized to the entire experimental situation.     

Involvement of MMPs in delayed neuronal death after global ischemia

Spatial and temporal relations between metalloproteinase (MMP-2 and MMP-9) activation and laminin degradation in gerbil hippocampus after transient cerebral ischemia has been studied. Activity of MMPs was determined by gelatin zymography in homogenates from dorsal (DP, an equivalent of CA1 sector) and abdominal (AbP, containing CA2-4 and gyrus dentatus) parts of hippocampus. A significant activation of both investigated metalloproteinases was found at 72 h of recovery. Whereas MMP-2 up-regulation did not show any spatial preferences, the increase of MMP-9 activity was observed exclusively in DP. Activation of MMP-9 at this time point correlated spatially with degradation of laminin-protein of extracellular matrix. These results show that MMP pathway may function as a component of delayed neuronal death cascade in the apoptogenic CA1 sector after transient global ischemia.     

Induction of interferon-inducible protein-10 and monokine induced by interferon-gamma from human endothelial cells infected with Influenza A virus

Primary human umbilical vein endothelial cells (HUVECs) were infected with Influenza virus A/Aichi/2/68 (H3N2) in order to determine the role of endothelial cells in mediating inflammation induced upon virus infection. Structural proteins of the virus and mRNA of the M2 protein were detected in the infected cells, indicating that virus infection had occurred in HUVECs. The Influenza A virus-infected HUVECs showed elevated levels of gene expression of interferon (IFN)-inducible protein (IP)-10 and monokine induced by IFN-gamma (Mig), while heat-, formalin- and diethyl ether-inactivated viruses did not enhance the IP-10 and Mig gene expression. The results thus indicate that infection of live Influenza A virus is responsible for elevation of IP-10 and Mig gene expression. The elevation of IP-10 and Mig gene expression in infected HUVECs was not accompanied by the elevation of IFN-gamma gene expression, indicating that the elevation of IP-10 and Mig gene expression was independent of the IFN-gamma pathway.     

Protein micelles of human histocompatibility antigens (HLA-A and HLA-B)

Human histocompatibility antigens (HLA-A and -B) are membrane proteins which have large hydrophilic domains outside the cell membrane and a small hydrophobic portion in the lipid bilayer. In this paper we describe optimal conditions for preparing micelles of detergent-solubilized HLA-A2 and -B7 antigens. These homogeneous protein aggregates are water soluble and free of detergent and lipid. Hydrophobic interactions between the intramembraneous portions of the HLA antigens are the driving forces in the formation of these protein micelles. The papain-solubilized fragment of the HLA antigens is not included in the micelle. The average molecular weight of the HLA micelles is around 9 × 10⁵ daltons, which suggests sixteen HLA-A2 and/or HLA-B7 antigenic molecules per protein aggregate. Electron microscopic studies revealed that the most frequent size of the micelles is 12 mm and that HLA-micelles are similar but not identical to micelles from Sindbis Virus glycoproteins (E1 and E2) The HLA-A2 and -B7 micelles retained full antigenic activity as judged by precipitations with allo- and heteroantisera. Such micelles will no doubt be important tools in further studies of the role of histocompatibility antigens.