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B Reis

Publications and source records attributed to B Reis.

15 recordsLinked to original sources
PubMed2004

Measuring outbreak-detection performance by using controlled feature set simulations.

INTRODUCTION: The outbreak-detection performance of a syndromic surveillance system can be measured in terms of its ability to detect signal (i.e., disease outbreak) against background noise (i.e., normally varying baseline disease in the region). Such benchmarking requires training and the use of validation data sets. Because only a limited number of persons have been infected with agents of biologic terrorism, data are generally unavailable, and simulation is necessary. An approach for evaluation of outbreak-detection algorithms was developed that uses semisynthetic data sets to provide real background (which effectively becomes the noise in the signal-to-noise problem) with artificially injected signal. The injected signal is defined by a controlled feature set of variable parameters, including size, shape, and duration. OBJECTIVES: This report defines a flexible approach to evaluating public health surveillance systems for early detection of outbreaks and provides examples of its use. METHODS: The stages of outbreak detection are described, followed by the procedure for creating data sets for benchmarking performance. Approaches to setting parameters for simulated outbreaks by using controlled feature sets are detailed, and metrics for detection performance are proposed. Finally, a series of experiments using semisynthetic data sets with artificially introduced outbreaks defined with controlled feature sets is reviewed. RESULTS: These experiments indicate the flexibility of controlled feature set simulation for evaluating outbreak-detection sensitivity and specificity, optimizing attributes of detection algorithms (e.g., temporal windows), choosing approaches to syndrome groupings, and determining best strategies for integrating data from multiple sources. CONCLUSIONS: The use of semisynthetic data sets containing authentic baseline and simulated outbreaks defined by a controlled feature set provides a valuable means for benchmarking the detection performance of syndromic surveillance systems.

Disease Outbreaks↗
PubMed1999

Expression of major histocompatibility class II antigens on polymorphonuclear neutrophils in patients with Wegener's granulomatosis.

BACKGROUND: Wegener's granulomatosis is a systemic inflammatory disease of unknown etiology. Many studies suggest that autoimmune reactions are involved, and there is good evidence for the participation of immunocompetent cells. In that context, we examined the activation of polymorphonuclear neutrophils (PMNs) of patients with Wegener's granulomatosis. METHODS: In a prospective study, the expression on the surface of PMNs of CD64 and of the major histocompatibility class II (MHC II) antigen was measured by cytofluorometry in whole blood. The expression of those antigens was correlated to disease activity. RESULTS: Up to 15% of the peripheral PMNs of patients with active disease expressed MHC II. Follow-up studies showed that expression correlated closely with disease activity and that it decreased rapidly under immunosuppressive therapy. Expression of CD64 was seen in approximately 50% of the patients, regardless of disease activity. CONCLUSION: MHC II expression on PMNs might serve as a novel diagnostic marker for active disease and appears to be suitable for monitoring immunotherapy. Moreover, our data provide evidence that PMNs, which are normally MHC II negative, acquire MHC II antigens in the course of disease and may be an unrecognized function within the afferent limb of the immune response.

Anti-Inflammatory Agents↗
PubMed1998

Fibronectin synthesis by human tubular epithelial cells in culture: effects of PDGF and TGF-beta on synthesis and splicing.

BACKGROUND: Enhanced synthesis of extracellular matrix proteins including fibronectin (FN) is associated with the development of sclerosis. In this context we studied FN synthesis by tubular epithelial cells in response to transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF). METHODS: FN protein synthesis by human tubular epithelial cells in culture (TEC) was measured by biosynthetic labeling and ELISA. Splicing of FN was assessed by RT-PCR and by Northern blotting. RESULTS: Cultivated TEC synthesized and released FN, the majority of which was deposited as an unsoluble protein and a minor portion (10 to 15%) was released into the supernatant. TGF-beta and, to a lesser degree, PDGF, up-regulated FN synthesis. All three FN splice variants (EDA, EDB, and IIICS) were produced. PDGF did not influence the splicing. TGF-beta preferentially up-regulated the EDA splice variant, but had no effect on the splicing of the other domains. CONCLUSIONS: PDGF and TGF-beta both up-regulate FN synthesis of TEC. TGF-beta, but not PDGF, also changed the quality of the de novo synthesized FN, and thus has a different role in the development of sclerosis.

Cells, Cultured↗
PubMed1995

Proteolytic processing of human cytomegalovirus glycoprotein B (gpUL55) is mediated by the human endoprotease furin.

Inhibition of endoproteolytic cleavage of glycoprotein B (gB; gpUL55) of human cytomegalovirus was achieved by treatment of infected fibroblasts with decanoyl peptidyl chloromethyl ketone (decRVKR-CMK), which inhibits the action of cellular subtilisin-like endoproteases with the amino acid recognition motif R x K/R R. Uncleaved gB precursor molecules of 160 kDa that were accumulated were endoglycosidase H resistant, suggesting that correct cellular transport occurred in the presence of the drug. The inhibitor also prevented endoproteolytic gB processing in CV-1 cells infected with a recombinant vaccinia virus-gB construct (VVgB). Evidence for direct involvement of the ubiquitous subtilisin-like endoprotease furin in gB cleavage was obtained from the observation that coinfection of CV-1 cells with WgB and a recombinant vaccinia-human furin construct reestablished endoproteolytic activity which was normally absent late after infection with WgB alone.

Cells, Cultured↗
PubMed1995

Constitutive expression of human cytomegalovirus glycoprotein B (gpUL55) with mutagenized carboxy-terminal hydrophobic domains.

Stable transfectants were selected from human astrocytoma cells (U373) after transfection with recombinant expression vectors carrying the human cytomegalovirus (HCMV) glycoprotein B (gB; gpUL55) gene with alternative deletions of hydrophobic domain segment 1 (hd1) or segment 2 (hd2) of the carboxy-terminal potential bipartite membrane anchor domain. Comparative analysis of HCMV gB forms from cell lines gB(Mhd1) and gB(Mhd2), expressing mutagenized gB, and those from cells expressing authentic gB showed that deletion of hd1, but not that of hd2, interfered with efficient proteolytic cleavage of the gB precursor. Both mutagenized gB forms exhibited correct transport to the cell surface. Deletion of hd2, but not that of hd1, caused loss of membrane anchoring of the gB molecule, resulting in secretion of the respective gB form into the culture medium. The carboxy-terminal cleavage product of the soluble gB molecule, which migrated more slowly than its authentic counterpart, was modified by complex carbohydrate side chains and formed disulphide-linked complexes. Our observations indicate that hd2 is essential as well as sufficient for membrane anchoring of the HCMV gB molecule. For hd1, a potential fusogenic role is suggested by the conserved positional pattern of glycine residues, which is comparable to that of known fusion peptides of other viruses.

Amino Acid Sequence↗
PubMed1994

Structural analysis of the US-segment of a viable temperature sensitive human cytomegalovirus mutant.

Structural analysis of the US-segment of a viable temperature sensitive human cytomegalovirus mutant (ts9) by the use of restriction enzymes, specific amplifications by the polymerase chain reaction and DNA sequencing, revealed deletions of open reading frames (orf) US14 and part of US15 in addition to that concerning US1 through US13 as reported previously [9]. It was further verified that the Hind III H-fragment and a major portion of the Hind III W-fragment were duplicated in inverted orientation. By the use of a monospecific antibody prepared against a procaryotic recombinant US11-specific product it was shown that the ts9 mutant was in fact deficient in a 30 kDa polypeptide, the gene product of orf US11.

Base Sequence↗
PubMed1993

Identification of the gene product encoded by ORF UL56 of the human cytomegalovirus genome.

Experiments were undertaken to identify the product of open reading frame (orf) UL56 of human cytomegalovirus (HCMV), the putative homolog of infected cell protein (ICP) 18.5 of herpes simplex virus type 1 (HSV-1) that is thought to be involved in viral nucleocapsid maturation. Northern blotting using a unique fragment of orf UL56 revealed a specific transcript of about 3.0 kb in HCMV-infected fibroblasts early and late postinfection (p.i.). Two overlapping fragments of UL56 were subcloned for procaryotic expression and the recombinant proteins were used for affinity purification of an antibody fraction from human convalescent serum (pab UL56). The affinity purified antibody recognized a polypeptide with an apparent molecular weight of about 130 kDa (p 130) in immunoblots of virions and of infected cell extracts late p.i. Upon treatment of isolated virions with nonionic detergent the p 130 polypeptide separated with the nucleocapsid/tegument fraction. The amino acid sequence of p 130 deduced from the nucleotide sequence exhibited a high homology to ICP 18.5 of HSV-1.

Blotting, Northern↗
PubMed1993

Stable constitutive expression of glycoprotein B (gpUL55) of human cytomegalovirus in permissive astrocytoma cells.

Permanent cell lines showing homogeneous constitutive expression of glycoprotein B (gpUL55; gB) of human cytomegalovirus (HCMV) were selected, in the presence of geneticin, from human astrocytoma cells (U373) after transfection with recombinant pRC/CMV-gB carrying the complete coding sequence for HCMV gB and for aminoglycoside phosphotransferase. The biosynthesis and processing including specific proteolytic cleavage, formation of disulphide-linked oligomers as well as transport of recombinant gB in three of four established transformed cell lines essentially resembled that found in infected parental U373 except for eventual degradation after 2 h of gB synthesis. Analysis of the fourth transformant expressing uncleaved gB suggested that proteolytic cleavage is not required for normal intracellular transport. The stable transformants retained permissiveness for productive superinfection with HCMV. The application of cell lines transformed with mutagenized HCMV gB for the rescue of genetically engineered HCMV mutants is discussed.

Astrocytoma↗
PubMed1993

Progeny vaccinia and human cytomegalovirus particles utilize early endosomal cisternae for their envelopes.

We have investigated by electron microscopy the envelopment of progeny human cytomegalovirus particles and vaccinia virus particles. As host cells we used primary human foreskin fibroblasts, in which both viruses replicate, and also AtT20 cells in which vaccinia virus, but not human cytomegalovirus, replicates. As we show here, primary human foreskin fibroblasts contain tubular early endosomes like those in AtT20 cells and many other cells in culture. Our aim was to ascertain whether or not the cisternae which wrap the maturing progeny viral particles are related to tubular endosomes. When infected cells were incubated with the fluid phase endocytic tracer horseradish peroxidase (HRP) at appropriate times after infection (5-8 h post vaccinia infection and 72 h or 96 h post cytomegalovirus infection), we found that many of the partially or fully enveloped vaccinia and human cytomegalovirus particles in the cytoplasm had HRP reaction product in the lumen of their cisternal envelope. Examination of single and serial sections indicated that the cisternal envelopes of the progeny virions were derived from tubular endosomes. Pulse-chase experiments with HRP showed that the viral particles with envelopes derived from tubular endosomes were not directed to late endosomes and autophagic digestion but were released from the cells. Experiments with Brefeldin A established that the envelopment of viral particles by endosomal cisternae proceeded for at least 2 h in the absence of a Golgi apparatus. Our data indicate that vaccinia virus and human cytomegalovirus (and presumably other pox and herpes viruses) have evolved to utilize early endocytic compartments to achieve their egress from host cells. We also found that in cells infected by vaccinia virus the delivery of the endocytic tracer to the Golgi apparatus is greatly enhanced over that in controls or cells infected with human cytomegalovirus. The cytopathic effects of vaccinia virus therefore include perturbation of membrane traffic between endocytic and exocytic compartments.

Brefeldin A↗
PubMed1992

Recognition of compartmentalized intracellular analogs of glycoprotein H of human cytomegalovirus.

Infected cell proteins immunoprecipitated from human cytomegalovirus (HCMV)-infected fibroblasts with glycoprotein H (gH)-specific conformation-dependent monoclonal antibody (mab 14-4 b) were found to consist of three components of 86 kDa, 89 kDa, and 125 kDa (gp 86, 89, and 125). Affinity purified antibodies from human convalescent serum reactive with an NH2-terminal epitope of gH recognized three polypeptides of comparable size in immunoblots, suggesting antigenic relatedness of these three components of the gH-complex. Using subcellular fractions for immunoblotting, gp 86 was identified as an endoglycosidase H (endo H)-sensitive gH-form present in the nuclear fraction whereas gp 89 and gp 125 were endo H-resistant and present in the membrane fraction or in virions. Incomplete endo H-digestion suggested that four of six predicted N-glycosylation sites of the gH molecule were occupied by carbohydrate side chains. Analysis under nonreducing conditions revealed that the compartmentalized as well as virion-associated gH analogs form high molecular weight complexes. The relation of the recognized gH analogs to the processing pathway of gH is discussed.

Cells, Cultured↗
PubMed1992

[Gastrinoma localized in the pylorus in a patient with recurrent peptic ulcer].

We report a clinical case of a woman, 56 years old, with a history of duodenal ulcer and esophagitis, under medication with H2 receptors blockers during 3 years. Plasma basal gastrin was near normal levels. A stimulation test with secretin was compatible with gastrinoma. CT scan and selective angiography didn't localize the tumor. At laparotomy we found a pyloric nodule that prove to be the gastrinoma. Eighteen months after surgery the patient is asymptomatic and with a normal endoscopic examination and secretin stimulation test.

Duodenal Ulcer↗
PubMed1984

Inhibition of DNA binding of purified p55v-myc in vitro by antibodies against bacterially expressed myc protein and a synthetic peptide.

To identify viral myc proteins, we have prepared myc-specific antibodies: (i) against a synthetic peptide corresponding to the nine carboxy-terminal amino acids of the viral myc (C9); (ii) against a bacterially expressed viral myc protein obtained by inserting the SalI-BamHI fragment of the viral MC29 DNA clone in the expression vector pPLc24. Both antisera recognize a protein of 55 000 mol. wt., p55v-myc, in MH2- and OK10-transformed fibroblasts. The protein is located in the nucleus, as shown by indirect immunofluorescence and cell fractionation. Antibodies against the C9 peptide were used to purify the p55v-myc by immunoaffinity column purification (3000-fold) from OK10- and MH2-transformed fibroblasts. p55v-myc binds to double-stranded DNA in vitro as does p110gag-myc. DNA binding in vitro is inhibited by the immunoglobulin fraction of antibodies against the bacterially expressed myc protein. Furthermore, a synthetic peptide consisting of 16 amino acids (C16) was used to isolate specific immunoglobulins which also inhibit DNA binding in vitro. OK10 codes, in addition to p55v-myc, for a p200gag-pol-myc polyprotein. The majority of this protein is located in the cytoplasm (79%). The purified protein binds to single-stranded RNA in vitro, unlike other gag-myc or myc proteins.

Antibodies, Viral↗