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PubMed1992

Characterization and comparison of two newly established Epstein-Barr virus (EBV)-negative and EBV-positive Burkitt's lymphoma cell lines. EBV-negative cell line with a low level of expression of ICAM-1 molecule and EBV-positive cell line with a high level of expression of ICAM-1 molecule.

Two human Burkitt's lymphoma cell lines (HBL-4 and HBL-5) were established individually from two patients with small noncleaved cell lymphoma (Burkitt's type). The HBL-4 cell line is Epstein-Barr virus (EBV)-negative, and the HBL-5 cell line is EBV-positive. Cytogenetically, both cell lines had the same chromosomal translocation, t(8;14)(q24;q32) as those observed in the primary malignant cells from individual patients. Morphologic, immunophenotypic, cytogenetic, and molecular studies confirmed that both cell lines were derived from the primary lymphoma cells in vivo. HBL-4 cells lacked CD23(H107), CD11a(LFA-1), and latent membrane protein (LMP) but expressed CD54(ICAM-1) at low levels, whereas HBL-5 cells showed the high level of expression of CD54 and faint expression of LMP but lacked CD11a. In addition, the EBV-positive lymphoblastoid cell line (LCL) expressed CD11a, CD23, CD54, and LMP at high levels. Therefore, an HBL-5 phenotype with expression of CD54 and LMP tends toward an LCL phenotype, and the augmentation of CD54 on the HBL-5 cells in comparison with primary lymphoma cells is likely to be upregulated by LMP, probably resulting from the EBV infection. There was little difference in the BrdUrd uptake in vivo and in vitro, doubling time, tumorigenicity, and dynamics of tumor growth in athymic nude mice between both cell lines. These findings indicate that the potentiality of cell growth and tumorigenicity of these two cell lines are unlikely to be related with EBV.

Adult↗

PubMed1998

Impaired production of IL-12 in system lupus erythematosus. II: IL-12 production in vitro is correlated negatively with serum IL-10, positively with serum IFN-gamma and negatively with disease activity in SLE.

Interleukin 12 (IL-12) is a key cytokine in regulating type 1 or type 2 cytokine production and in determining the nature of immune responses. Our previous studies demonstrated that its production was significantly impaired in systemic lupus erythematosus (SLE) patients and this deficient IL-12 production was mainly mediated by excessive endogenous IL-10. The present study was designed to further reveal the relationships of in vitro IL-12 production with abnormalities of in vivo cytokine synthesis and disease activity in SLE. Experimental results showed that IL-12 production in vitro was inversely correlated with serum IL-10 level, anti-ds DNA antibody level and SLE disease activity index (DAI), but positively correlated with serum interferon gamma (IFN-gamma) level, with which serum IL-10 correlated negatively. Data also showed that serum IL-10 was significantly higher than that of controls and closely correlated with anti-ds DNA antibody level and SLEDAI. The study confirms that deficient IL-12 production in SLE patients is associated with in vivo abnormalities of cytokine production, especially with increased IL-10 production.

Adult↗

PubMed2005

Fragmentation of negative ions from carbohydrates: part 1. Use of nitrate and other anionic adducts for the production of negative ion electrospray spectra from N-linked carbohydrates.

Negative ion spectra of N-linked glycans were produced by electrospray from a dilute solution of the glycans and various salts in methanol:water using a Waters-Micromass Q-TOF Ultima Global tandem quadrupole/time-of-flight (Q-TOF) mass spectrometer. Stable anionic adducts were formed with chloride, bromide, iodide, nitrate, sulphate, and phosphate. Unstable adducts that fragmented by a cross-ring cleavage of the reducing N-acetylglucosamine (GlcNAc) residue, were formed with fluoride, nitride, sulphide, carbonate, bicarbonate, hydroxide, and acetate. Nitrate adducts prepared from ammonium nitrate produced the most satisfactory spectra as they were relatively free from in-source fragmentation products and gave signals that were about ten times as strong as those from corresponding [M - H]- ions prepared from solutions containing ammonium hydroxide. Detection limits were in the region of 20 fmol. Neutral glycans gave both singly- and doubly-charged ions with the larger glycans preferring the formation of doubly-charged ions. Acidic glycans with several acidic groups gave ions in higher charge states as the result of ionization of the anionic groups. Low energy collision-induced decomposition (CID) spectra of the singly-charged ions were dominated by cross-ring and C-type fragments, unlike the corresponding spectra of the positive ions that contained mainly B- and Y-type glycosidic fragments. Formation of these ions could be rationalized by proton abstraction from various hydroxy groups by an initially-formed anionic adduct. Prominent glycosidic and cross-ring cleavage ions defined structural features such as the specific composition of each of the two antennae, presence of a bisecting GlcNAc residue and location of fucose residues, details that were difficult to determine by conventional techniques. Acidic glycans fragmented differently on account of charge localization on the acid functions rather than the hydroxy groups.

Anions↗

PubMed1989

Ester and related derivatives of ring N-pentafluorobenzylated 5-hydroxymethyluracil. Hydrolytic stability, mass spectral properties, and trace detection by gas chromatography-electron-capture detection, gas chromatography-electron-capture negative ion mass spectrometry, and moving-belt liquid chromatography-electron-capture negative ion mass spectrometry.

One consequence of radiation damage to DNA is the conversion of thymine to 5-hydroxymethyluracil (HMU). In order to sensitively detect this DNA adduct by gas chromatography (GC) or high-performance liquid chromatography (HPLC) with electron-capture detection techniques, it is necessary to derivatize it. This study was designed to select an optimum ester derivative of the aliphatic hydroxyl group on HMU. N1, N3-Bis(pentafluorobenzyl)-HMU was formed as a parent derivative, and from this a series of esters. Also O-pentafluorobenzyl and O-tetrafluorobenzyl ether derivatives were prepared. Of the esters the pivalyl derivative was the best choice because it formed easily, was relatively stable to aqueous hydrolysis (t 1/2 = 9.8 days at pH 11.5, 24 degrees C) and gave a response at fmol levels by GC and LC comparable to that of the ethers. Unanticipated was a good response as well for the parent derivative, a free hydroxyl compound, by GC and LC at this level. The work also demonstrates a high performance by LC-electron-capture negative ion mass spectrometry with a belt interface for the trace detection of derivatives of this type.

Chemical Phenomena↗

PubMed1987

Comparison between positive, negative and chloride-enhanced negative chemical ionization of organophosphorus pesticides in on-line liquid chromatography-mass spectrometry.

Positive and negative chemical ionization (PCI and NCI, respectively) have been used for the characterization of ten organophosphorus pesticides in on-line liquid chromatography-mass spectrometry (LC-MS). LC analyses were performed on a 20 cm X 0.7 mm I.D. C8-bonded phase using acetonitrile-water (70:30) or acetonitrile-water-chloroacetonitrile (69:30:1) as eluent. With PCI, molecular weight information was obtained with both eluents. For NCI considerable differences in the spectra were found using the two eluents. Without chloroacetonitrile the spectra were dominated by the functional group fragment and with chloroacetonitrile the base peak was [M - R]- with R being methyl or ethyl, while the spectra further contained the functional group ions. Special emphasis was devoted to the occurrence of chloride attachment at different source temperatures. With several compounds the [M + Cl]- ion was formed and its relative intensity strongly increased when the source temperature decreased. With NCI the sensitivity was about one order of magnitude better than with PCI. This advantage was partly lost when 1% of chloroacetonitrile was used in the eluent; on the other hand, complementary structural information was obtained. As an application, the determination of three organophosphorus pesticides in sediment is reported.

Chemical Phenomena↗

PubMed2000

Dissociative prime-probe contextual similarity effects on negative priming and repetition priming: a challenge to episodic retrieval as a unified account of negative priming.

This study examined the dependence of repetition priming (RP) and negative priming (NP) as a function of prime-probe contextual similarity in a paradigm in which participants were required to respond to a letter flanked by incompatible distractor letters (e.g., ABA). Experiment 1 used prime and probe displays containing a pair of "+" symbols that were presented horizontally or vertically. Experiments 2 and 3 manipulated whether the letter triplets contained the "!" symbol. In all experiments, regardless of whether the RP trials were intermixed with the NP trials (Experiment 2) or not (Experiment 3), RP was stronger in the prime-probe similar conditions than in the prime-probe dissimilar conditions, but NP was independent of prime-probe contextual similarity. These findings suggest that NP is not necessarily stronger in conditions in which episodic retrieval of the prime is more likely.

Adolescent↗

PubMed2001

Negative knee arthroscopy: Is it really negative?

PURPOSE: To evaluate the outcome of patients in whom knee arthroscopy proved to be normal. TYPE OF STUDY: Retrospective study. METHODS: Knee arthroscopy is probably the most common procedure performed in orthopaedic practice. A number of patients who undergo this procedure do not have any abnormality detected. Is negative arthroscopy really such an unnecessary procedure? Hospital records of patients who had undergone knee arthroscopy were retrospectively studied and all patients with a normal knee arthroscopy were selected. Fifty-three patients (55 knees) with a normal arthroscopy were included into the study. Patients were then interviewed either by telephone or questionnaire to ascertain current symptoms, job changes, and patient perception of the procedure. RESULTS: The mean follow-up was 43 months. Fifty percent of the patients had a history of injury, and the preoperative diagnosis was thought to be a meniscal lesion or a rupture of the anterior cruciate ligament in 38% of patients. Sixty-eight percent of the patients felt that they were better and there were no complications. The incidence of all symptoms were significantly reduced after arthroscopy. CONCLUSIONS: A significant number of patients felt that they were better after the knee arthroscopy. The reason for this is not entirely clear. It may well be attributable to a placebo effect, the fact that patients now know that there is no abnormality and learn to live with the symptoms, or there may be an additional benefit of the procedure itself.

Adolescent↗

PubMed2002

Serious infections caused by enteric gram-negative bacilli--mechanisms of antibiotic resistance and implications for therapy of gram-negative sepsis in the transplanted patient.

The Enterobacteriaceae (eg, Escherichia coli, Klebsiella spp., Enterobacter spp.) are common causes of intraabdominal, respiratory tract, and bloodstream infections in transplant recipients. Antibiotic resistance in these organisms is increasing. The major mechanism of resistance to cephalosporins is beta-lactamase production. The most important beta-lactamases are the inducible group 1 cephalosporinases, which are resistant to beta-lactamase inhibitors, and the plasmid-mediated extended-spectrum beta-lactamases (ESBLs). Organisms producing these beta-lactamases also may be resistant to quinolones and aminoglycosides by different mechanisms. A worrying recent development has been the detection of plasmid-mediated carbapenemases, which can inactivate antibiotics such as imipenem and meropenem. In general, third-generation cephalosporins should be avoided in the therapy of serious infections in transplant recipients because of the common occurrence of cephalospo-rinases in the Enterobacteriaceae. Antibiotic options are becoming more limited as the prevalence of resistance mechanisms in gram-negative bacilli increases.

Bacillus↗

PubMed1998

A negative vitamin D response DNA element in the human parathyroid hormone-related peptide gene binds to vitamin D receptor along with Ku antigen to mediate negative gene regulation by vitamin D.

We found that the human parathyroid hormone-related peptide (hPTHrP) gene contained a DNA element (nVDREhPTHrP) homologous to a negative vitamin D response element in the human parathyroid hormone gene. It bound to vitamin D receptor (VDR) but not retinoic acid Xalpha receptor (RXRalpha) in the human T cell line MT2 cells. VDR binding to this element was confirmed by the Southwestern assay combined with immunodepletion using anti-VDR monoclonal antibody, and this binding activity was repressed by 1,25-dihydroxyvitamin D3. Such a repression was reversed by acid phosphatase treatment, suggesting that 1,25-dihydroxyvitamin D3 phosphorylates VDR to weaken its binding activity to nVDREhPTHrP. In electrophoretic mobility shift assay, we found anti-Ku antigen antibody specifically supershifted the MT2 nuclear proteinnVDREhPTHrP complex. The nVDREhPTHrP-bearing reporter plasmid produced vitamin D-dependent inhibition of the reporter activity in MT2 cells, which was markedly masked by the introduction of the Ku antigen expression vector in the antisense orientation. On the other hand, such a procedure did not perturb the vitamin D response element-mediated gene stimulation by vitamin D. These results indicate that nVDREhPTHrP interacts with Ku antigen in addition to VDR to mediate gene suppression by vitamin D.

Antigens, Nuclear↗

PubMed2006

The Drosophila inhibitor of apoptosis (IAP) DIAP2 is dispensable for cell survival, required for the innate immune response to gram-negative bacterial infection, and can be negatively regulated by the reaper/hid/grim family of IAP-binding apoptosis inducers.

Many inhibitor of apoptosis (IAP) family proteins inhibit apoptosis. IAPs contain N-terminal baculovirus IAP repeat domains and a C-terminal RING ubiquitin ligase domain. Drosophila IAP DIAP1 is essential for the survival of many cells, protecting them from apoptosis by inhibiting active caspases. Apoptosis initiates when proteins such as Reaper, Hid, and Grim bind a surface groove in DIAP1 baculovirus IAP repeat domains via an N-terminal IAP-binding motif. This evolutionarily conserved interaction disrupts DIAP1-caspase interactions, unleashing apoptosis-inducing caspase activity. A second Drosophila IAP, DIAP2, also binds Rpr and Hid and inhibits apoptosis in multiple contexts when overexpressed. However, due to a lack of mutants, little is known about the normal functions of DIAP2. We report the generation of diap2 null mutants. These flies are viable and show no defects in developmental or stress-induced apoptosis. Instead, DIAP2 is required for the innate immune response to Gram-negative bacterial infection. DIAP2 promotes cytoplasmic cleavage and nuclear translocation of the NF-kappaB homolog Relish, and this requires the DIAP2 RING domain. Increasing the genetic dose of diap2 results in an increased immune response, whereas expression of Rpr or Hid results in down-regulation of DIAP2 protein levels. Together these observations suggest that DIAP2 can regulate immune signaling in a dose-dependent manner, and this can be regulated by IBM-containing proteins. Therefore, diap2 may identify a point of convergence between apoptosis and immune signaling pathways.

Animals↗

PubMed2005

A negative Helicobacter pylori serology test is more reliable for exclusion of premalignant gastric conditions than a negative test for current H. pylori infection: a report on histology and H. pylori detection in the general adult population.

OBJECTIVE: Corpus-dominant gastritis, gastric mucosal atrophy and intestinal metaplasia (IM) associated with Helicobacter pylori infection are all known potential risk markers for the development of gastric cancer. As the accuracy for finding cases at risk in the general population is unknown, we aimed to determine the prevalence of current and/or past H. pylori infection and associated gastric mucosal findings by means of histological survey of a random adult population. MATERIAL AND METHODS: A random Swedish sample (n = 3000, age 20-81 years) was surveyed using a validated gastrointestinal symptom questionnaire with 74% response rate. One-third of the responders were selected at random for esophago-gastro-duodenoscopy with biopsies and H. pylori serology. RESULTS: Of those endoscoped (n = 1000, mean age 53.5, 51% women), 43.0% were H. pylori+ by serology (seropositive), 33.9% had signs of current infection on either histology or culture (gold standard+), and 9.3% were seropositive, but gold standard negative. Corpus atrophy was found in 10% and IM in 13% when gold standard positive, and in a significantly higher number (17% and 21%, respectively) of those with only a serological sign of past infection. Among those who were seronegative, values were 1% and 2%, respectively. Corpus-dominant gastritis was found in 4.1%, all seropositive. CONCLUSION: One-third had an ongoing H. pylori infection, and a further 10% had signs of past infection. Corpus-dominant gastritis was found mostly among the former, while detection of those with corpus atrophy and IM also required a test for past infection. Seronegativity almost excludes precancerous conditions in a screening situation.

Adult↗

PubMed2004

Airborne dispersal as a novel transmission route of coagulase-negative staphylococci: interaction between coagulase-negative staphylococci and rhinovirus infection.

OBJECTIVE: To investigate whether rhinovirus infection leads to increased airborne dispersal of coagulase-negative staphylococci (CoNS). DESIGN: Prospective nonrandomized intervention trial. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Twelve nasal Staphylococcus aureus-CoNS carriers among 685 students screened for S. aureus nasal carriage. INTERVENTIONS: Participants were studied for airborne dispersal of CoNS in a chamber under three conditions (street clothes, sterile gown with a mask, and sterile gown without a mask). After 2 days of pre-exposure measurements, volunteers were inoculated with a rhinovirus and observed for 14 days. Daily quantitative nasal and skin cultures for CoNS and nasal cultures for rhinovirus were performed. In addition, assessment of cold symptoms was performed daily, mucous samples were collected, and serum titers before and after rhinovirus inoculation were obtained. Sneezing, coughing, and talking events were recorded during chamber sessions. RESULTS: All participants had at least one nasal wash positive for rhinovirus and 10 developed a symptomatic cold. Postexposure, there was a twofold increase in airborne CoNS (P = .0004), peaking at day 12. CoNS dispersal was reduced by wearing a gown (57% reduction, P < .0001), but not a mask (P = .7). Nasal and skin CoNS colonization increased after rhinovirus infection (P < .05). CONCLUSIONS: We believe this is the first demonstration that a viral pathogen in the upper airways can increase airborne dispersal of CoNS in nasal S. aureus carriers. Gowns, gloves, and caps had a protective effect, whereas wearing a mask did not further reduce airborne spread.

Adult↗

PubMed2003

Transmission of HIV type 1 through blood transfusion from an antibody-negative/p24 antigen-negative donor.

Transmission of HIV through transfusion occurred in a 78-year-old male after receiving red blood cells from a 27-year-old woman, who was negative for HIV antibodies and p24 antigen at the time of donation, but seroconverted thereafter. Plasma viral load at donation was 2538 HIV RNA copies/ml. Phylogenetic analyses demonstrated that viruses from both patients clustered tightly together, belonged to subtype B clade, and had no primary drug resistance mutations. This case highlights the residual risk of HIV transmission from donors in the window period, and supports the implementation of nucleic acid testing in blood banks.

Adult↗

PubMed1991

Proliferation of double-negative (CD4-CD8-) T cells bearing T-cell receptor-alpha beta in a haemophiliac with human immunodeficiency virus type 1 infection and factor VIII inhibitor: functional properties of double-negative T-cell receptor-alpha beta+ T cells.

We present a patient with haemophilia A showing human immunodeficiency virus type 1 (HIV-1) infection and factor VIII inhibitor in whom a novel T-cell subpopulation, double-negative (CD4-CD8-) T cells bearing T-cell receptor (TCR)-alpha beta, proliferated polyclonally in the peripheral blood. An interleukin-2-dependent T-cell line with a CD4-CD8-TCR-alpha beta+ phenotype was established from the peripheral blood lymphocytes of the patient, and its biological functions were studied. It was found that the CD4-CD8-TCR-alpha beta+ T cells possessed both HLA-unrestricted cytotoxicity and helper function for immunoglobulin production by B cells. In addition, these T cells were found to produce interferon-gamma and interleukin-2 following activation via CD3-TCR complexes. These data demonstrating the multifunction of these newly defined CD4-CD8-TCR-alpha beta+ T cells thus suggest that these cells play an important role in protection against HIV infection. The mechanism of production of factor VIII inhibitor in the present case is also discussed focusing on the CD4-CD8-TCR-alpha beta+ T cells.

Adult↗

PubMed1990

Computed tomography scans and negative symptoms in schizophrenia: chronic schizophrenics with negative symptoms and nonenlarged lateral ventricles.

Computed tomography scans of 31 chronic schizophrenics with negative symptoms and 31 age-matched normal volunteers were assessed for ventricular size, cortical atrophies, third ventricle diameter, and cerebellar atrophies. No significant differences were found in the size of the lateral ventricles or third ventricles between the chronic schizophrenics and the controls. The frontal horns in patients did show a tendency toward increased size compared with controls. Sulci width showed significant differences between patients and controls. The clinical variables, except for the memory test, did not correlate with any brain morphology. A meta-analysis was performed on 17 studies that used the planimetric method in order to evaluate the relationships between the size of the lateral ventricles in patients and their respective controls. We found significant differences between the group of studies using normal controls and the group using medical controls.

Adult↗

PubMed1998

Identification of positive and negative regulatory regions involved in regulating expression of the human cytomegalovirus UL94 late promoter: role of IE2-86 and cellular p53 in mediating negative regulatory function.

The human cytomegalovirus (HCMV) UL94 gene product is a herpesvirus-common virion protein that is expressed with true late kinetics. To identify the important cis- and trans-acting factors which contribute to UL94 transcriptional regulation, we have cloned, sequenced, and analyzed UL94 promoter function by transient transfection analysis. Transfection of UL94 promoter-reporter gene constructs into permissive human fibroblasts or U373(MG) cells indicated that promoter activity was detected following infection with HCMV. Point mutations within a TATA-like element located upstream of the RNA start site significantly reduced UL94 promoter activity. Deletion mutagenesis of the promoter indicated that a positive regulatory element (PRE) was likely to exist downstream of the UL94 mRNA start site, while a negative regulatory element (NRE) was present upstream of the TATA box. At late times of infection, the PRE appeared to have a dominant effect over the NRE to stimulate maximum levels of UL94 promoter activity, while at earlier times of infection, no activity associated with the PRE could be detected. The NRE, however, appeared to cause constitutive down-regulation of UL94 promoter activity. Binding sites for the cellular p53 protein located within the NRE appeared to contribute to NRE function, and NRE function could be recapitulated in cotransfection assays by concomitant expression of p53 and HCMV IE2-86 protein. Our results suggest a novel mechanism by which the cellular protein p53, which is involved in both transcriptional regulation and progression of cellular DNA synthesis, plays a central role in the regulation of a viral promoter which is not activated prior the onset of viral DNA replication.

Base Sequence↗

PubMed1996

Criticism of cardiovascular studies with negative results due to a negative correlation.

BACKGROUND: Trials that do not allow rejection of the null hypothesis of no treatment effect may have had an inappropriate design. Self- controlled trials, although routinely used for the study of cardiovascular diseases, are virtually never assessed for correlation between treatment modalities. METHODS: Using three models and a series of published studies as examples, the author studies the influence of correlation levels on the statistical power of self-controlled studies. RESULTS: Between-subject variation as estimated by SD is largely dependent on the level of correlation, and so is the power of testing. The assessment of paired data as though they are unpaired can be used as a simple test to estimate correlation levels. CONCLUSION: It is extremely relevant to assess correlation levels in a paired comparison a priori. With a presumably negative correlation, a self- controlled design is likely to lack power.

Cardiovascular Diseases↗

PubMed1975

[Gram negative bacillus septicemias. Results of treatment of 31 gram negative bacillus septicemias using intravenous nalidixic acid].

Enterobacteria multiresistant to usual antibiotics, often remain sensitive to nalidixic acid, sometimes as a result of synergy with polymixins. Use of the intravenous route makes it possible to obtain more than adequate serum levels. Pharmacological study has indicated appropriate doses in terms of renal function. Intravenous nalidixic acid has been used in the treatment of 31 cases of Gram negative septicaemia, with success in 22. These results are all the more significant given that the patients were all seriously ill, cultures having grown multiresistant organisms and that nalidixic acid was used only after other antibiotics had failed.

Anuria↗