Use of specific ELISA for the detection of antibodies directed against p53 protein in patients with hepatocellular carcinoma.

AIMS: To analyse the significance of antibodies to p53 protein as a serological marker for changes in p53 gene expression in patients with hepatocellular carcinoma. METHODS: Thirty eight patients with hepatocellular carcinoma, 19 showing accumulation of p53 protein by immunohistochemistry and 19 having no accumulation, were studied. The presence of anti-p53 was tested using a novel ELISA utilising a recombinant p53 protein as a capture system and verified by western blotting. p53 gene mutations were sought by single strand conformational polymorphism and DNA sequencing analyses. RESULTS: Of 19 patients with p53 protein accumulation in tumour tissue, 10 (52%) had antibodies to p53 in serum by ELISA. Four patients with p53 negative immunohistochemistry also had detectable anti-p53. Western blot analysis confirmed the specificity of the ELISA positive serum samples. The presence of anti-p53 was independent of serum alpha-fetoprotein and was detected in 50% of small tumours while only 8% were alpha-fetoprotein positive. Mutations affecting exons 5 and 6 seem to be more frequently associated with development of anti-p53, than mutations in exons 7 or 8. CONCLUSIONS: The ELISA for anti-p53 is a convenient and specific tet for the detection of humoral response to alterations in p53 gene expression and could be of value in the diagnosis and characterisation of patients with hepatocellular carcinoma.     

In situ immunogold labeling analysis of the rice hoja blanca virus nucleoprotein and major noncapsid protein.

Ribonucleoprotein particles (RNPs) of rice hoja blanca virus (RHBV) were purified and used for electron microscopic analysis and antibody production. Antibodies made to RNPs specifically decorated purified RNPs. The RNPs typically showed characteristic tenuivirus morphologies. They were approximately 8 nm in diameter, mostly circular in nature, and exhibited branching and a high degree of superhelicity. When the RNP antibodies were used for in situ immunogold labeling analysis of RHBV-infected tissues, no specific structures were identified, but gold particles were distributed throughout the cytosol of RHBV-infected but not healthy plants. However, amorphous semi-electron opaque inclusion bodies (ASO-IBs) were abundant in cells of RHBV-infected plants. While the ASO-IBs were not labeled with the anti-RNP antiserum, they were specifically labeled with antibodies to the RHBV major noncapsid protein (NCP) and with antibodies to the NCP of another tenuivirus, maize stripe virus.     

5-Azacytidine produces differential undercondensation of alpha,beta and classical human satellite DNAs

Fluorescencein situ hybridization employing human alphoid, beta and classical satellite DNA probes was performed on 5-azacytidine treated and untreated chromosomes obtained from human lymphocytes. The individual used in this study presented a polymorphism of constitutive heterochromatin of chromosomes 1 and 9 as revealed byin situ digestion with the restriction endonucleaseAlul. Neither the alphoid nor the beta satellite DNA domains were susceptible to condensation-inhibition by 5-azacytidine. Only the classical satellite localized on chromosome 9 was affected. The constitutive heterochromatin size polymorphism was shown to depend mainly on variations of the classical satellite DNA domain. Therefore, condensation-inhibition, as a phenomenon which may modify the natural folding of the chromatin fibre, regionally affects human constitutive heterochromatin and seems to be dependent on the heterochromatic family.     

Comparison of enzyme-linked immunosorbent assay, indirect immunofluorescence assay, and virus isolation for detection of respiratory viruses in nasopharyngeal secretions.

Nasopharyngeal secretions obtained from 94 children with acute respiratory illness were examined for the presence of respiratory syncytial virus (RSV), adenovirus, and influenza virus type A by virus culturing (virus isolation technique [VIT]), immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA). Similar results were obtained in at least two tests for RSV, influenza virus type A, and adenovirus in 92 (97.9%), 88 (93.6%), and 88 (93.6%) cases, respectively. Both rapid virus detection methods showed good specificity for the diagnosis of these virus infections (greater than or equal to 90.7%) and were more sensitive than was VIT for RSV detection. In a more accurate statistical analysis, the indexes of agreement between VIT and ELISA were substantial for RSV (kappa = 0.69; zeta = 5.5; P less than 0.0001), influenza virus type A (kappa = 0.67; zeta = 5.3; P less than 0.0001), and adenovirus (kappa = 0.71; zeta = 6.0; P less than 0.0001), while it was almost perfect for RSV when ELISA was compared with IFA (kappa = 0.88; zeta = 5.7; P less than 0.0001). Although the observed agreement was good in the comparison of these two tests for these three viruses (89%0, the indexes of agreement were moderate in the comparison of IFA and VIT for RSV (K = 0.55; Z = 2.0; P < 0.05), influenza virus type A (K = 0.42; Z = 9.7; P < 0.0001), and adenovirus (K = 0.41; Z = 6.5; P < 0.0001) and of ELISA and IFA for influenza virus type A (K = 0.55; Z = 7.0; P < 0.0001) and adenovirus (K = 0.59; Z = 6.8; P < 0.0001). All of the statistical evaluations demonstrated better agreement between ELISA and VIT for influenza virus type A and adenovirus.     

Adenocarcinomas of the nasal cavity and paranasal sinuses: a clinicopathological and immunohistochemical study of 14 cases

Aims : To evaluate the clinicopathological profile of 14 cases of nasal and paranasal sinusal adenocarcinoma, and to assess the usefulness of immunohistochemistry in the differential diagnosis of primary and metastatic intestinal-type adenocarcinoma.
Methods and results : Fourteen cases of nasal and paranasal adenocarcinoma, treated at IPOFG, Lisbon, between 1976 and 2002, were studied. Clinical records were reviewed and expression of cytokeratin (CK)7 and CK20 and of neuroendocrine markers was evaluated. The male : female ratio was 3 : 1, and the mean age of the patients was 65.3 years. Ten cases occurred in the paranasal sinuses. There was a history of professional exposure to dust in three patients. Twelve cases were high-grade intestinal type adenocarcinomas (ITAC) and two were low-grade. CK7 was present in 2/9 ITAC cases and CK20 in 8/9 ITAC and in cases of mixed and mucinous histology. All high-grade cases showed neuroendocrine differentiation. Seven of the 12 patients with high-grade adenocarcinoma died of the disease, with a mean follow-up of 47.4 months.
Conclusions : Nasal and paranasal adenocarcinoma mostly occurs in men in the 7th decade. ITAC is the most frequent histological type. The pattern of CK7/CK20 was not useful in the distinction between primary and metastatic intestinal adenocarcinoma. However, in the former, neuroendocrine differentiation proved to be a valuable tool in that distinction.     

Quantitation of a cationic antimicrobial granule protein of human polymorphonuclear leukocytes by ELISA

The quantitation of CAP57, a highly hydrophobic, native cationic antigen of human polymorphonuclear leukocytes has been achieved using ELISA. An important feature determining the sensitivity and precision of the ELISA was the reduction of non-specific protein-protein binding, particularly in the inhibition assays, thus eliminating high backgrounds obtained with presently available methodology. Washing of the solid phase-bound antigen and blocking of the non-specific binding sites using a potassium phosphate buffer containing heparin largely contributed to this increased sensitivity. The inhibition assays were conducted using antigen concentrations over the range of 0.9-120 ng. The assay is highly specific and can be performed using monoclonal antibodies and polyclonal antibodies. Non-specific reactions were observed only when high concentrations of antigen (greater than 100 ng) were present in the inhibition mixture. The technique as described is extremely simple, highly reproducible and could be of value in the detection of cationic antimicrobial proteins in the clinical setting in the future.     

High- and low-density lipoproteins enhance infection of Trypanosoma cruzi in vitro

Trypanosoma cruzi exhibits a developmentally regulated neuraminidase activity that is inhibited by high-density lipoprotein (HDL). We report here that the infection of culture cells by T. cruzi trypomastigotes is enhanced by HDL in a dose-dependent manner. The enhanced infection is prevented by Vibrio cholerae neuraminidase, an enzyme whose activity is not inhibited by HDL, suggesting that sialic acid is involved in T. cruzi-host interaction. Similar enhancement of infection is also produced by low-density lipoprotein (LDL), which inhibits T. cruzi neuraminidase as well as HDL. Further evidence that the enhancement is due to lipoproteins is provided by the fact that infection of host cells in lipoprotein-deficient medium is less than in normal medium; it can be restored to the higher level by the addition of HDL, LDL or both to the lipoprotein-deficient medium. In view of these results, we propose that HDL and LDL regulate T. cruzi infection in mammalian hosts by inhibiting the parasite neuraminidase activity.