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F Negro

Publications and source records attributed to F Negro.

At least 109 records · Page 6Linked to original sources
PubMed1992

Detection of cytomegalovirus by in situ hybridization using a digoxigenin-tailed oligonucleotide.

A non-isotopic in situ hybridization procedure was used to detect cytomegalovirus (CMV) sequences within routinely fixed tissue. A digoxigenin-tailed oligonucleotide was hybridized to sections of specimens obtained at autopsy from 2 patients with CMV infection. Hybrids were revealed by an alkaline phosphatase-conjugated anti-digoxigenin antibody. Serial sections were also assayed for the presence of CMV by in situ hybridization with a biotin-labelled cDNA probe and by immunohistochemistry and routinely stained for morphological evaluation. Results show that the two in situ hybridization procedures are equally sensitive but superior to the immunohistochemical detection of the viral antigen. Most cells positive for CMV DNA had the cytopathological features characteristic of CMV infection. A minor population of infected cells lacking morphological changes was also found. We recommend the routine application of the oligonucleotide-based assay because it is specific, easy and less expensive than other similar procedures.

Alkaline Phosphatase↗
PubMed1992

In situ hybridization in viral hepatitis.

In situ hybridization (ISH) is a sensitive and specific technique for detecting nucleic acids in intact cells. Visualization of the target sequences by autoradiography or immunohistochemistry allows their precise subcellular localization and quantitation. The application of ISH techniques has contributed to the understanding of the complex replicative cycle of hepatitis B virus. More recently, hepatitis delta and C virus replication has also been studied by this technique. ISH-based assays have finally been used to follow the replication of cytomegalovirus within the transplanted liver. Although ISH is a powerful tool for the molecular biologist, its clinical significance in the diagnosis and prognosis of human hepatitis virus infections has yet to be fully evaluated.

Hepacivirus↗
PubMed1991

Hepatitis delta virus heterogeneity: a study by immunofluorescence.

Hepatitis delta virus (HDV)-RNA shows a microheterogeneity at nucleotide 1015 resulting in the production of two co-terminal forms of the HDV-associated antigen (HDAg), referred to as p24 and p27. In vitro experiments have shown that p24 is localized within the nucleolus, while p27 expression is probably confined to the nucleoplasm. The sequential appearance of these two proteins may play a role in the HDV-induced cell damage. We have examined 12 formalin-fixed human liver biopsies taken at different phases of the natural course of HDV infection. Specimens were assayed for HDAg by direct immunofluorescence with a human IgG reactive towards both p24 and p27. Positive cells were then examined for cytopathological features after hematoxylin/eosin staining. All biopsies contained intranuclear HDAg. However, three different patterns of fluorescence were seen: (1) nucleolar with weak nucleoplasmic; (2) homogeneous nucleoplasmic with negative nucleolus; (3) intense fluorescence diffuse to the whole nucleus. Pattern 1 was found in 15-50% of positive nuclei of all samples, irrespective of the phase of infection, while the remaining positive nuclei mostly showed another pattern (2) of fluorescence. Neither pattern was associated with cytoplasmic eosinophilia. Degenerated hepatocytes, when infected (5%), showed pattern 3 of HDAg fluorescence but were mostly negative for HDV. Therefore, the intranuclear distribution of HDAg, as assayed in vivo, does not seem to correlate with peculiar phases of HDV infection. Different phases of the viral life style, instead, are asynchronously represented within each liver sample.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Viral↗
PubMed1990

APACHE II score does not predict multiple organ failure or mortality in postoperative surgical patients.

A clinical study was undertaken to evaluate the ability of the APACHE (acute physiology and chronic health care) II system to predict the development of multiple organ failure syndrome and subsequent mortality. The study was conducted in a university general surgery intensive care unit using the admission APACHE II score. Over a 1-year period, 92 patients qualified for the study, 24 of whom survived, 69 of whom suffered multiple organ failure syndrome, and 68 of whom died. The APACHE II score did not predict the development of multiple organ failure syndrome or mortality with clinical utility and significantly underestimated the potential for the development of multiple organ failure syndrome. Factors that did predict the development of multiple organ failure syndrome and mortality were the time-dependent changes in the PaO2-to-fraction of inspired oxygen ratio and serum lactate, creatinine, and bilirubin levels. Better markers of cell injury are needed for use in decision making and quality assurance analysis in surgical patients.

Humans↗
PubMed1989

Intrahepatic markers of hepatitis delta virus infection: a study by in situ hybridization.

The intrahepatic distribution of hepatitis delta virus RNA was studied by in situ hybridization in 33 formalin-fixed, paraffin-embedded biopsies from 17 chronic hepatitis B virus carriers superinfected with hepatitis delta virus. The findings were correlated with the expression of the hepatitis delta antigen, the duration of the hepatitis delta virus infection and the eosinophilic degeneration of the hepatocytes. Intranuclear hepatitis delta virus RNA and antigen were found in 28 specimens, whereas the remaining five were negative for both markers. Hepatitis delta virus RNA and antigen were mostly found within the same cell. In 20 specimens, however, a variable number of hepatocytes showed the presence of hepatitis delta virus RNA alone. The percentage of these over the total number of infected cells was higher in the specimens taken within 1 year from the acute delta hepatitis, whereas their absence was invariably associated with a long-established hepatitis delta virus infection. Interestingly, the vast majority of hepatocytes undergoing eosinophilic degeneration, a change significantly associated with hepatitis delta virus infection, did not show the presence of either hepatitis delta virus RNA or the viral antigen, suggesting a lack of association, at the cellular level, between viral replication and cytopathological change. The specificity of the detection of hepatitis delta virus RNA was confirmed by negative findings in nine specimens from seven chronic hepatitis B virus carriers without evidence of past or current hepatitis delta virus infection. The loss in sensitivity due to the formalin fixation was estimated to be 50% of that obtained in frozen biopsies, as determined by counting autoradiographic grains over infected cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Human herpes virus-6 increases HIV-1 expression in co-infected T cells via nuclear factors binding to the HIV-1 enhancer.

Human Herpes virus-6 (HHV-6) can co-infect with HIV-1 human CD4+ T-cells, leading to accelerated cell death, and factors in HHV-6-infected cells stimulate HIV-1 LTR directed gene expression. In this study, we have examined the mechanism of HIV-1 activation by HHV-6 and localized the cis-acting sequences of HIV-1 LTR responsive to trans-activation. Increased HIV-1 LTR directed gene expression is obtained in HIV-1 infected cells co-infected with HHV-6, or in HHV-6 infected cells co-transfected with the HIV-1 tat gene. Parallel increases of HIV-1-specific transcripts are seen by in situ hybridization in HHV-6/HIV-1 doubly infected cells as compared to single HIV-1 infection. Similarly, infection by HHV-6 increases the steady-state level of HIV-1 LTR mRNA that parallels CAT enzymatic activity, suggesting a transcriptional and/or post-transcriptional activation. Sequences necessary for HIV-1 LTR activation by HHV-6 are distinct from those required for that tat response and map to a region of the HIV-1 LTR from -103 to -48. The HIV-1 enhancer sequence (-105 to -80) is sufficient to confer HHV-6 inducibility to a heterologous promoter, and nuclear protein(s) activated or induced by HHV-6 infection specifically bind to the NF kappa B motifs of the HIV-1 enhancer region.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1989

Reappearance of hepatitis D virus (HDV) replication in chronic hepatitis B virus carrier chimpanzees rechallenged with HDV.

Four chronic hepatitis B virus (HBV) carrier chimpanzees, which had apparently cleared hepatitis D virus (HDV) after a first experimental challenge with HDV, were reinoculated with a homologous strain of HDV. All animals had reappearance of low levels of serum HDV RNA and transient, mild alanine aminotransferase (ALT) elevations, which in two cases correlated with HDV RNA positivity. Plasmas obtained from two chimpanzees after rechallenge were inoculated into two other chronic HBV carrier animals that had recovered from a previous HDV infection. A similar reappearance of HDV RNA in serum (without ALT elevation) was noticed. These same plasmas, however, when inoculated into a chronic HBV carrier chimpanzee never exposed to HDV caused a severe acute hepatitis D. Rechallenge with HDV in chimpanzees apparently recovered from a first HDV infection resulted in the reappearance of HDV replication, sometimes associated with hepatitis. This can be interpreted as reinfection with HDV, but other explanations are possible. Although the serum level of HDV RNA observed after rechallenge with HDV is low, its transmission to individuals susceptible to HDV infection can result in severe acute hepatitis D.

Alanine Transaminase↗