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Biomedical subjects

P Schiller

Publications and source records attributed to P Schiller.

17 recordsLinked to original sources
PubMed1992

Rapid complementation assay for anti-HIV-1 drug screening and analysis of envelope protein function.

A complementation assay is described that can be used with relative safety to quantitate rapidly inhibitory effects of potential anti-HIV-1 drugs on virtually any stage of the HIV-1 life cycle by measurements of chloramphenicol acetyltransferase (CAT) activity. Of particular interest is that this system is also capable of detecting inhibition of the viral trans-activator Rev, an important potential target for drug intervention. Other applications of the system may include studies to identify domains of the envelope glycoprotein that determine infectivity and tropism or that define epitopes recognized by neutralization antibodies.

Antiviral Agents↗
PubMed1992

HIV-1 in postmortem brain tissue from patients with AIDS: a comparison of different detection techniques.

OBJECTIVE: The presence of HIV-1 in postmortem brain tissue from 31 patients with AIDS and 12 HIV-1-negative controls was investigated. DESIGN: Most laboratories have access to the methods used. We readily applied in situ hybridization and immunohistochemistry to archival formalin-fixed paraffin-embedded (FFPE) brain specimens. METHODS: The techniques used to detect HIV-1 were explant culture, in situ hybridization with 35S-labeled polymerase (pol) gene riboprobes and immunohistochemistry with monoclonal antibody to gp41. RESULTS: HIV-1 was isolated from explant cultures in 13 out of 20 (65%) patients, whereas HIV-1-infected cells were detected in FFPE brain tissue from nine out of 26 (35%) patients examined by in situ hybridization and in seven out of 26 (27%) patients examined by immunohistochemistry. CONCLUSIONS: Although the isolation technique was the most sensitive of the three techniques tested, infected cells may be identified with in situ hybridization in conjunction with immunohistochemistry.

AIDS-Related Opportunistic Infections↗
PubMed1991

Coincidence of schizophrenia and hyperbilirubinemia.

In a retrospective study, the bilirubin plasma concentrations of every patient admitted to the Psychiatric Hospital were collected. Patients suffering from liver disease, substance abuse, overt hemolysis, or increased liver enzymes were excluded. Schizophrenics showed a significantly higher incidence of hyperbilirubinemia than patients suffering from other psychiatric disorders. This phenomenon seems to be independent of drug usage and therefore points to a relationship between hyperbilirubinemia and schizophrenic psychosis. Hypothetic explanations, such as a possible genetic disposition for Gilbert Syndrome, an increased vulnerability of red-cell membranes, and the role of estrogens in schizophrenic patients, are discussed.

Adult↗
PubMed1991

HIV-1 propagates in human neuroblastoma cells.

A major question in the pathogenesis of AIDS encephalopathy and dementia is whether HIV-1 directly infects cells of the central nervous system (CNS). The propagation of HIV was attempted in six cell lines: three related and three unrelated to the nervous system. HIV was able to propagate in two human neuroblastoma cell lines and a lymphocytic cell line control but did not result in infections of African green monkey kidney cells, human cervix carcinoma cells, and one human brain astrocytoma cell line. Neuroblastoma cell lines infected with HIV showed peaks of reverse transcriptase activity at 10-14 days postinfection. After prolonged growth in cell cultures, one of the neuroblastoma cell lines showed multiphasic virus production, additional high peaks of reverse transcriptase activity, 20-fold greater than the first, lasting from 36 to 74 days and 110 to 140 days postinfection. The presence of HIV was confirmed by p24 antigen capture. The neuroblastoma cell lines had weak but detectable levels of CD4 immunoreactivity by immunoperoxidase and flow immunocytometric analysis. Although no T4-specific RNA sequences were detected by hybridization of Northern blots of total and poly A-selected RNA extracted from the two neuroblastoma cell lines by using a T4 specific complimentary DNA probe, monoclonal antibodies to the CD4 receptor blocked HIV infection in both neuroblastoma cell lines. Thus, the infection of neuroblastoma cells by HIV occurs in part by a CD4-dependent mechanism. Passaging the neuroblastoma cell lines weekly and bimonthly resulted in similar cell cycle-DNA content patterns for the more permissive cell line and with significant numbers of cells in the S phase. HIV-infected neuroblastoma cell lines provide an in vitro model for the evaluation of virus-host cell interactions and may be useful in addressing the issue of the persistence of HIV in the human CNS.

Animals↗
PubMed1989

[Role of echography in the screening of congenital hip luxation at a maternity department].

Ultrasound was established as a remarkable means of recognizing dysplasia of hips or dislocations in the neonatal period following the work of R. Graf and later in France of H. Gomes and J. Schirrer et al. All the same, different techniques have been suggested and the role of the examination has been debated. Those who advocate routine screening of all pregnancies are in opposition to those who employ it selectively in cases that are known to be abnormal or at risk. The authors report a study carried out in their maternity department using ultrasound of the hip as an examination complementary to clinical screening. Echography has been shown to be able to give more information than radiography of the pelvis which cannot usefully be employed for screening until the age of 4 months. In 1781 newborns examined consecutively the indication for ultrasound of the hip was suggested in 201 cases (11%) and showed an abnormality in 42 patients (21% of the examinations carried out). Exenteration in 2, dysplasia in 8, failure to ossify correctly in 25, and endoscopic laxity without a morphological abnormality in 7 cases. The clinical signs that were used to predict an abnormality on ultrasound were: feminine sex. Clinical appearance of instability and the association of 2 risk factors. 3 cases of dislocation were found. Two of them occurred early and one at the age of 5 months who was a girl delivered by the breech and in whom a delay in ossification was noted at birth.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1988

Cis-acting elements involved in the regulated expression of a human HSP70 gene.

Expression of reporter genes under the control of upstream sequences of a human hsp70 gene was examined in microinjected Xenopus oocytes, transfected monkey COS and human HeLa cells. The genes were strictly heat-regulated in all three cell systems. A 69 nucleotide long segment of hsp70 5' non-transcribed sequence that included at least one functional heat shock regulation sequence was sufficient for heat-controlled expression in Xenopus and monkey cells but not in human HeLa cells. An additional segment of about 200 nucleotides in length was required for optimal activity. This segment contains two heat shock regulation elements, each of which appears to contribute to the overall activity in heat-treated human cells. Upstream non-transcribed sequences of the human hsp70 gene are capable of conferring heat regulation on a heterologous promoter. The potential roles in transcription regulation of a bending center in the TATA box region, a CCAAT-like sequence and some of many potential Sp1 binding sites in the hsp70 5' non-transcribed region were investigated.

Animals↗
PubMed1988

Determinants for the DNase I-hypersensitive chromatin structure 5' to a human HSP70 gene.

A DNase I hypersensitive site was detected in chromatin formed over a human hsp70 gene segment after amplification in COS7 cells. Deletion mutant analysis was used to evaluate the sequence requirements for this chromatin structure. Determinants sufficient to form the hypersensitive site are contained in a 280 base-pair sequence corresponding approximately to the region that is hypersensitive. Deletion of sequences from either end of this region resulted in reduced hypersensitivity, suggesting that multiple genetic elements contribute to the formation of this chromatin structure. As has been reported for other heat shock genes, the hypersensitive chromatin structure is present prior to heat treatment and does not change in intensity or position after heat shock, in spite of the fact that hsp70 gene expression is completely dependent on heat induction. Sequence requirements for hypersensitivity were generally similar to those for heat-induced gene expression when mutant plasmids were tested at low copy number (e.g. in HeLa cells or in COS cells without amplification); however, deletion of sequences between -223 and -162 with respect to the start of transcription abolished the hypersensitive site but had no effect on gene expression. A barrier to exonuclease III digestion was detected within this region (near an imperfect inverted repeat sequence centered at position -202), suggesting that proteins are tightly bound to the DNA at this location.

Animals↗
PubMed1987

A murine monoclonal antibody against rat atrial natriuretic factor (ANF) which cross-reacts with mouse ANF.

A monoclonal antibody (MAb), 2H2, against rat synthetic atrial natriuretic factor (ANF) (Arg101-Tyr126) recognizes native ANF related peptides. The lack of reactivity of 2H2 with amino-terminal truncated ANF peptides implicates the two amino terminal arginine residues of ANF in the 2H2 epitope. Similarly, poor immunoreactivity of human ANF indicates the participation of isoleucine 110. Arginines 101 and 102 and isoleucine 110 may thus participate in a conformational epitope recognized by 2H2 or alternatively, substitution for, or elimination of these residues may alter the conformation of the 2H2 epitope. The MAb shows little cross-reactivity with extracts of rabbit atria but recognizes ANF related peptides in mouse and hamster atrial extracts. 2H2 also identifies immunoreactive ANF in histological sections of rat, mouse and hamster atria.

Animals↗
PubMed1987

Organization of the Drosophila melanogaster hsp70 heat shock regulation unit.

Expression from the Drosophila melanogaster hsp70 promoter was controlled by a regulatory unit that was composed of two sequence elements that resembled the heat shock consensus sequence. The unit functioned in both orientations and at different distances from downstream promoter sequences. Each element of the unit alone was essentially inactive. Association of two elements resulted in a dramatic increase of transcription from the hsp70 promoter. This synergistic effect was independent of the relative orientation of the elements and, to a large extent, of the distance between them. Duplication of a region containing only one element also yielded a highly active, heat-regulated promoter. Genes with three to five elements were three to four times more active than those with a single regulatory unit.

Animals↗
PubMed1986

Heat shock and ecdysterone activation of the Drosophila melanogaster hsp23 gene; a sequence element implied in developmental regulation.

The regulation of the Drosophila melanogaster hsp23 gene by heat shock and ecdysterone has been analysed by measuring activities of hsp--Escherichia coli beta-galactosidase hybrid genes in transfected hormone-sensitive D. melanogaster cells. Mutation analysis identified multiple, distinct promoter elements. A sequence element, which also occurs in the promoters of several other developmentally regulated Drosophila genes, is present in regions of the hsp23 promoter that are essential for its ecdysterone, but not its heat-regulated activity; this element may represent a binding site for an ecdysterone--receptor complex. Mutant promoters that can be activated only by heat shock or by hormone have been constructed. Thus the two types of regulation of the hsp23 gene can function independently of each other.

Animals↗
PubMed1985

Identification of a sequence element in the promoter of the Drosophila melanogaster hsp23 gene that is required for its heat activation.

The expression of Drosophila melanogaster hsp23-Escherichia coli beta-galactosidase hybrid genes containing different segments of the 5' non-transcribed sequence of the hsp23 gene has been examined at the RNA and protein levels in Xenopus oocytes. Transcription of the hybrid genes is initiated correctly. Mutant genes with hsp23 gene promoter segments of at least 140 bp in length are strongly heat-activated while genes with shorter promoter segments are expressed constitutively and at low levels. This maps an element required for the heat-controlled expression of the D. melanogaster hsp23 gene to a region, approximately 140 bp upstream from the start of the transcription site, which contains a sequence (CGAGAAGTT-TCGTGT) that is closely related to the one responsible for the heat regulation of the hsp70 gene. These findings demonstrate the importance of this regulatory sequence for a second hsp gene and support the notion that hsp genes are heat-regulated by a common mechanism. The functional element in the hsp23 gene promoter is located greater than 80 bp further upstream from the TATA box than the relevant element in the hsp70 gene promoter. Even though other related sequences are present further upstream and downstream from the functional element, they play at most an auxiliary role in the regulation of hsp23 gene expression.

Animals↗