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Biomedical subjects

M Camera

Publications and source records attributed to M Camera.

7 recordsLinked to original sources

Hypertriglyceridemia and regulation of fibrinolytic activity.

A relation between elevated triglyceride (TG) levels and alterations of the fibrinolytic system has been recognized in studies of patients with coronary heart disease. In this investigation, the total fibrinolytic activity and the levels of specific components of the fibrinolytic system were evaluated in plasma samples from a highly selected group of patients with type IV hyperlipoproteinemia before and after a dietary treatment aimed at reducing TG levels. The fibrinolytic response of type IV patients was comparable to that of normolipidemic subjects, whereas tissue-type plasminogen activator antigen levels before and after venous occlusion (p less than 0.01) and resting plasminogen activator inhibitor-1 (PAI-1) antigen (p less than 0.01) and activity (p less than 0.01) were significantly higher in hypertriglyceridemic subjects compared with controls. After dietary treatment, a 22% reduction in TG levels was attained in type IV patients, with no appreciable modification of fibrinolytic parameters. The analysis of the single-patient data revealed a tendency toward normalization of PAI-1 levels only in those patients who showed a TG reduction greater than or equal to 20%. Very low density lipoproteins (VLDLs) from both normal and type IV patients concentration-dependently stimulated PAI-1 release by endothelial cells and HepG2 cells, with the effect of VLDL from type IV patients being more pronounced on HepG2 cells. The release of PAI-1 induced by VLDL in competent cells may thus account for the elevated levels of this antifibrinolytic protein that occur in hypertriglyceridemic patients.

Adult

Profile of sequential determinants in tissue polypeptide antigen BrCN:B fragment.

A synthetic approach has been applied to determine the profile of sequential determinants of one immunodominant region of Tissue Polypeptide Antigen (TPA). Five overlapping peptides, covering 30 of the 32 amino acid residues of this fragment, were chemically synthesized, and their antibody-binding activities for rabbit anti-TPA antibodies determined by enzyme-linked immunoadsorbant assays. Anti-TPA reacted with two overlapping fragments at the COOH-terminal end of the fragment, but not with peptides that include Arg 15 considered as essential for the antigenicity of the whole fragment. This might suggest that this critical residue is involved in the formation of a complex conformational determinant.

Amino Acid Sequence

14C-labeling of synthetic peptides.

Two methods are described for the labeling of synthetic peptides using iodo[14C]acetic acid. The first procedure may be employed when the synthetic fragment contains a cysteine with a free sulfhydryl group. Alternatively, a commercial amino-protected cysteine may be carboxymethylated using radioactive iodoacetic acid. This derivative can be added to the growing peptide chain in the manual or automatic solid-phase synthesis of the fragment.

Amino Acid Sequence

Restriction of anti-peptide antibody specificity by enzyme-modified Sepharose-peptide immunoadsorbents.

Sepharose-peptide immunoadsorbents, employed for the isolation of specific antibodies from the sera of rabbits immunized with carrier protein-peptide conjugates, were digested with suitable proteolytic enzymes, in order to obtain the splitting of a part of the peptide bound to the gel. This new modified immunoadsorbent can be advantageously used for the isolation of antibody subsets, that do not cross-react with related peptides exhibiting high sequence homology with the immunogens.

Amino Acid Sequence

Do monoclonal antibodies recognize linear sequential determinants?

A group of 19 anti-class II monoclonal antibodies produced in different laboratories were tested in ELISA for their ability to bind to a panel of synthetic peptides selected from HLA-DQ alpha and beta chains. No one of the antibodies tested was found to react with the synthetic fragments, thus confirming the common finding that MoAbs generally fail to recognize fragments of the native antigen. The possibility that this result might be partly due to the procedure used for screening hybridoma supernatants is discussed.

Antibodies, Monoclonal

[Hypoglycorrhachia as an early sign of central nervous system infection caused by HIV].

Cerebrospinal fluid (CSP) glucose values were measured in 37 HIV-positive patients with neurologic symptoms and in 35 HIV-negative controls affected by bacterial or viral meningo-encephalitis (ME). Low CSF glucose values were found more frequently in HIV+ patients (49% of cases) than in ME patients (14%). CSF/serum ratios for glucose were also significantly lower in HIV +. Mean serum glucose did not differ between the two groups. Since HIV is a strongly neurotropic and infects early the endothelial cells of the brain capillaris, where glucose is actively carried from plasma to CSP, it is hypothesized that low CSF glucose in HIV-infected patients with neurological symptoms might be an early sign of CNS invasion by the virus.

Acquired Immunodeficiency Syndrome