Biomedical subjects

J Blomberg

Publications and source records attributed to J Blomberg.

At least 19 recordsLinked to original sources

PubMed2006

SYBR Green real-time reverse transcription-polymerase chain reaction assay for the generic detection of coronaviruses.

Coronaviruses are etiologic agents of respiratory and enteric diseases in humans and in animals. In this study, a one-step real-time reverse transcription-polymerase chain reaction (RT-PCR) assay based on SYBR Green chemistry and degenerate primers was developed for the generic detection of coronaviruses. The primers, designed in the open reading frame 1b, enabled the detection of 32 animal coronaviruses including strains of canine coronavirus, feline coronavirus, transmissible gastroenteritis virus (TGEV), bovine coronavirus (BCoV), murine hepatitis virus (MHV) and infectious bronchitis virus (IBV). A specific amplification was also observed with the human coronaviruses (HCoV) HCoV-NL63, HCoV-OC43, HCoV-229E and severe acute respiratory syndrome coronavirus (SARS-CoV). The real-time RT-PCR detected down to 10 cRNA copies from TGEV, BCoV, SARS-CoV and IBV. In addition, the assay exhibited a high sensitivity and specificity on clinical samples from different animal species. The developed assay represents a potential tool for laboratory diagnostics and for detecting still uncharacterized coronaviruses.

Animals↗

PubMed2005

Classification of highly similar crude oils using data sets from comprehensive two-dimensional gas chromatography and multivariate techniques.

Comprehensive two-dimensional gas chromatography (GCxGC) has proven to be an extremely powerful separation technique for the analysis of complex volatile mixtures. This separation power can be used to discriminate between highly similar samples. In this article we will describe the use of GCxGC for the discrimination of crude oils from different reservoirs within one oil field. These highly complex chromatograms contain about 6000 individual, quantified components. Unfortunately, small differences in most of these 6000 components characterize the difference between these reservoirs. For this reason, multivariate-analysis (MVA) techniques are required for finding chemical profiles describing the differences between the reservoirs. Unfortunately, such methods cannot discern between 'informative variables', or peaks describing differences between samples, and 'uninformative variables', or peaks not describing relevant differences. For this reason, variable selection techniques are required. A selection based on information between duplicate measurements was used. With this information, 292 peaks were used for building a discrimination model. Validation was performed using the ratio of the sum of distances between groups and the sum of distances within groups. This step resulted in the detection of an outlier, which could be traced to a production problem, which could be explained retrospectively.

Chromatography, Gas↗

PubMed2005

Comprehensive multi-dimensional chromatographic studies on the separation of saturated hydrocarbon ring structures in petrochemical samples.

Characterization of complex petrochemical samples has been a classical subject of comprehensive two-dimensional (2D) gas chromatography (GC x GC). Macroscopic properties of these samples can be described accurately by separation of compounds in classes of identical molecular functionality. Ring structures in the carbon backbone of these compounds, which can be divided in saturated and unsaturated, are amongst the foremost functionalities affecting samples properties. Unfortunately, GC x GC tuned for separation of both saturated and unsaturated ring structures is likely to result in convoluted chromatograms when a distribution of both molecular properties is present in the sample. An independent liquid chromatographic (LC) separation preceding GC x GC could be used to resolve the mixture based on unsaturated rings, allowing saturated rings to be resolved separately in the GC x GC separation. This three-dimensional separation (abbreviated LC-GC x GC) was performed after rigorous evaluation of LC as part of a multidimensional separation using LC x GC. Group-type separation was achieved using this separation for components with either saturated or unsaturated rings. Results of this separation were used to compare information obtained by GC x GC with LC-GC x GC.

Chromatography, Gas↗

PubMed2003

Uptake of amplifiable fragments of retrotransposon DNA from the human alimentary tract.

Few attempts have been made to study the transfer of DNA from ingested food across the intestinal barrier. A low uptake of ingested DNA has been observed in mice, cattle and poultry. There have been no reports on humans so far. Maintenance of species barriers, protection against retrotransposons, optimisation of oral DNA vaccines and the fate of genetically modified foodstuffs are issues where this topic is of importance. We therefore used the high-copy-number rabbit retrotransposon RERV-H, and rabbit mitochondrial DNA, to study the transfer of DNA from ingested rabbit meat into the bloodstream of two human volunteers. A quantitative PCR was used to measure RERV-H levels in food and in the blood. Amplification with the primers selected results in the generation of a 250-bp fragment of RERV-H. Transfer across the intestinal epithelium could be demonstrated in both subjects. Levels of the fragment in the bloodstream peaked at 1-3 h after ingestion of the experimental meal. One hour after a meal of rabbit meat containing 10(14) copies of RERV-H DNA, a maximum concentration of 200 copies of RERV-H DNA per ml of peripheral blood was observed, which corresponds to the uptake of approximately 10(6) RERV-H DNA copies in 1 h. RERV-H DNA was detected in both cellular and plasma compartments. Both rabbit retrotransposon and mitochondrial DNA was taken up from the human alimentary tract. The size of the fragments detected is similar to that of SINE retrotransposons (approximately 300 bp). The fate and functionality of alimentary DNA in humans will require further study.

Administration, Oral↗

PubMed2002

Gas chromatographic methods for oil analysis.

In the past 50 years. gas chromatography (GC) has played a most important role in the analysis of oil. In this review, the early history is briefly reviewed; next developments in this highly relevant application area since about 1985 are highlighted. The main topic of interest are the introduction and decisive role of capillary GC, the use of selective detection techniques, the versatility of coupled-column techniques and, specifically, the additional power of comprehensive two-dimensional GC.

Chromatography, Gas↗

PubMed2001

Human retrovirus type 5 sequences in non-Hodgkin's lymphoma of T cell origin.

DNA of a recently described fifth exogenous retrovirus (HRV-5) has been found in blood samples from patients with autoimmune diseases and lymphoma. We analyzed HRV-5 sequence in DNA extracted from whole blood of 17 patients with T cell non-Hodgkin's lymphoma (NHL) and 186 patients with hematological malignancies other than NHL, using a sensitive PCR technique. While all samples of patients with hematological malignancies other than NHL were negative, 2 of the 17 patients with T cell NHL were HRV-5 DNA positive. Both HRV-5-positive patients had T cell NHL of high-grade malignancy (stage IV) and diffuse distribution of the lymphoma, including infiltration of bone marrow or lung and pleura. The difference in HRV-5 DNA detection frequency between NHL and control groups is significant (p value of 0.0004 judged by the Fisher exact test). These data, together with our previous finding of HRV-5 DNA in three B cell NHL cases, are compatible with an association between HRV-5 and NHL, of both T cell and B cell origin.

Amino Acid Sequence↗

PubMed2001

Sequence evolution and cross-reactive antibody responses to hypervariable region 1 in acute hepatitis C virus infection.

Hepatitis C virus (HCV) infection may result in acute resolving or chronic infection. Patients that clear the infection have a more vigorous cellular immune response and an early humoral response to the hypervariable region 1 (HVR1) of the E2 envelope protein. To analyse further the properties of the early anti-HVR1 response, cross-reactivity of anti-HVR1 responses was assessed in five patients with acute HCV infection, who were infected by the same virus strain during a nosocomial outbreak. The sequence evolution of HVR1 was examined in sequential serum samples up to 37 months post infection. Peptides were synthesised corresponding to the obtained HVR1 sequences and unrelated HVR1 sequences, and antibody reactivity to the peptides in sequential sera was investigated by ELISA. The results suggest an association between specific gaps in humoral immunity and the HVR1 sequence evolution during early infection. Possible interpretations of this phenomenon include immune escape mechanisms or suppression of specific anti-HVR1 antibodies.

Acute Disease↗

PubMed2001

Prevalence of blood-borne viral infections (cytomegalovirus, human herpesvirus-6, human herpesvirus-7, human herpesvirus-8, human T-cell lymphotropic virus-I/II, human retrovirus-5) among blood donors in Latvia.

The identification of blood-borne viral infections is important in transfusion medicine. The aim of this study was to evaluate the prevalence of human herpesvirus (HHV) [cytomegalovirus (CMV), HHV-6, HHV-7 HHV-8] and human retrovirus (HRV) (human T-cell lymphotropic virus (HTLV)-I/II, HRV-5) infections among apparently healthy Latvian blood donors. DNA extracted from peripheral blood leukocytes (PBL) of 150 individuals was tested for herpesviruses by sensitive polymerase chain reaction (PCR) technique. None of the blood donors was positive for HHV-8 infection, while the incidence of latent beta-herpesvirus infections was high: single infection by CMV, HHV-6, and HHV-7 was detected in 2.6%, 8.0%, and 43.3% of blood donors, respectively. Simultaneous dual and triple infections of these viruses were observed in 28.0% and 4.7% of individuals, respectively. Active infection by CMV and HHV-6 was not found, but HHV-7 DNA was present in plasma of 10.6% of the blood donors. While all blood donors were HTLV-II and HRV-5 negative, 4.6% of HTLV-I seronegative blood donors were positive for the HTLV-I tax gene, although none of them harbored sequences for structural genes of the provirus. Based on our results, we conclude that monitoring of beta-herpesvirus infections in blood donors can be important in cases of transfusions to immunocompromised persons. HHV-8, as well as the retroviruses HTLV-II and HRV-5, were not found in blood of Latvian blood donors. More investigations are required to explain the presence of the HTLV-I tax sequence in seronegative blood donors.

Adolescent↗

PubMed2001

Broad spectrum of time of detection, primary symptoms and disease progression in infants with HIV-1 infection.

The relationship between time of HIV-1 detection, appearance of symptoms and disease progression was studied in all 24 HIV-1-infected infants from a cohort of 117 children who were born to HIV-1-infected mothers and monitored from birth. HIV isolation from plasma and mononuclear cells, HIV-1 DNA PCR (polymerase chain reaction) and, retrospectively, a quantitative assay for HIV-1 RNA were used for virus detection. Two infants possibly exhibited a symptomatic primary HIV infection. More children with than without symptoms during the first year of life progressed to immunological class 3 (P=0.013) and to AIDS or death (P=0.003) during follow-up. HIV-1 was detected within 4 days of age in 4 of 16 infants: 3 of them became symptomatic within 1 year, as did 6 of the remaining 12 infants (not statistically significant). All four infants in whom virus was detected within 4 days of age progressed to severe immunosuppression, compared to 6 of 14 in whom the virus detection test was initially negative prior to the first positive result (n.s.). Two children with previous repeatedly negative HIV detection tests were diagnosed with HIV-1 infection at 8 and 9 months, respectively. Repeated blood sampling is needed for the diagnosis of HIV-1 infection in perinatally exposed infants, and virus detection tests for exclusion of HIV-1 infection must be used with caution.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Identification of novel porcine endogenous betaretrovirus sequences in miniature swine.

PCR amplification of genomic DNA from miniature swine peripheral blood lymphocytes, using primers corresponding to highly conserved regions of the polymerase (pol) gene, allowed the identification of two novel porcine endogenous retrovirus (PERV) sequences, PMSN-1 and PMSN-4. Phylogenetic analyses of the nucleotide sequences of PMSN-1 and PMSN-4 revealed them to be most closely related to betaretroviruses. The identification of PERVs belonging to the Betaretrovirus genus shows that endogenous retroviruses of this family are more broadly represented in mammalian species than previously appreciated. Both sequences contained inactivating mutations, implying that these particular loci are defective. However, Southern blot analysis showed additional copies of closely related proviruses in the miniature swine genome. Analyses of fetal and adult miniature swine tissues revealed a broad mRNA expression pattern of both PMSN-1 and PMSN-4. The most abundant expression was detected in whole bone marrow c-kit(+) (CD117(+)) progenitor bone marrow cells, fetal liver, salivary gland, and thymus. It appears unlikely that functional loci encoding these novel PERV sequences exist, but this remains to be established. The betaretrovirus sequences described in this report will allow such investigations to be actively pursued.

Animals↗

PubMed2000

Comparison of comprehensive two-dimensional gas chromatography and gas chromatography--mass spectrometry for the characterization of complex hydrocarbon mixtures.

In this paper, we compare the current separation power of comprehensive two-dimensional gas chromatography (GCxGC) with the potential separation power of GC-mass spectrometry (GC-MS) systems. Using simulated data, we may envisage a GC-MS contour plot, that can be compared with a GCxGC chromatogram. Real examples are used to demonstrate the current potential of the two techniques in the field of hydrocarbon analysis. As a separation technique for complex hydrocarbon mixtures, GCxGC is currently about as powerful as GC-MS is potentially powerful. GC-MS has not reached its potential separation power in this area, because a universal, soft ionization method does not exist. The greatest advantage of GCxGC is, however, its potential for quantitative analysis. Because flame-ionisation detection can be used, quantitative analysis by GCxGC is much more robust, reliable and reproducible.

Chromatography, Gas↗

PubMed2000

[Newly discovered human retroviruses. Association with disease is still undetermined].

Retroviruses are enveloped RNA viruses which can transcribe RNA to DNA and integrate into the chromosomal DNA of their host cell. Heritable integrations give rise to endogenous retroviral sequences (ERVs). The rest is exogenous, infecting from individual to individual. This survey highlights an emerging scenario in human retrovirology. Humans have thousands of distinct ERVs. Although most are damaged by mutations, many are expressed as RNA, a few also as proteins and viral particles. The latter are not known to be infectious. Obviously, human ancestors encountered many different exogenous retroviruses, some of which may still be extant. In fact, an exogenous retrovirus related to ERVs was recently discovered. It is the fifth human exogenous retrovirus, human retrovirus 5 (HRV-5). It succeeds the two human T-lymphotropic viruses (HTLVs) and the two human immunodeficiency viruses (HIVs). The newly discovered endogenous and exogenous human retroviruses are now being investigated for association with disease. There are indications of selective ERV activation in multiple sclerosis, schizophrenia and seminoma. HRV-5 has been associated with rheumatoid arthritis, systemic lupus erythematosus and non-Hodgkin lymphoma. It is not yet known whether these first observations signal a pathogenic role for the newly discovered retroviruses.

Animals↗

PubMed2000

Structural prerequisites for intersubtype B and D antigenicity of the third variable envelope region (V3) of human immunodeficiency virus type 1.

To elucidate the structural requirements for intersubtype antigenicity of human immunodeficiency virus type 1 (HIV-1) third variable envelope region (V3), synthetic peptides were used in enzyme immunoassays (EIAs) with serum samples from persons with proven or probable subtype B and D infections. Mathematical analyses of results from EIAs with singly substituted V3 peptides revealed important residues determining overall N-terminal V3 peptide antigenicity. This information was used to design V3 immunogens, rabbit antiserum to which were tested in EIA and for in vitro neutralization of molecular clones of HIV-1(MN) and HIV-1(MAL). Intersubtype-reactive epitopes were distributed toward the N-terminal half of the V3 loop. Lysine at position 310, arginine at position 311, and isoleucine at position 314, all derived from the MN primary sequence, were major determinants of intersubtype V3 antigenicity. Combinations of residues that enhanced antigenicity often contained lysine at position 310. Threonine at position 308 was common in the least advantageous combinations. V3 immunogens modified to achieve optimal antigenicity induced antiserum with augmented cross-neutralization of virus from MAL and MN molecular clones, suggesting one approach to subunit vaccine development.

Amino Acid Sequence↗

PubMed2000

Human retrovirus 5 sequences in peripheral blood cells of patients with B-cell non-Hodgkin's lymphoma.

A recently described sequence from a probable 5th human exogenous retrovirus, HRV-5, is related to type A, B and D retroviruses. It was initially detected in a salivary gland biopsy from a patient with Sjögren's syndrome, but it is not consistently associated with this disease. We searched for the HRV-5 sequence in DNA extracted from whole blood of 300 blood donors, 81 patients with hematological malignancy and 21 patients with neurological disease using PCR. While samples from none of the blood donors and the neurological patients became positive, 3 of the 81 patients with hematological malignancy were HRV-5 DNA positive. All 3 had B-cell non-Hodgkin's lymphoma of low grade. The difference in frequency between NHL and controls is statistically significant. HRV-5 DNA was found in DNA from whole blood and in plastic-adherent cells but not in tumor cell DNA. Thus, monocytes/macrophages may be preferred targets for HRV-5. Our result, together with a previous finding of HRV-5 DNA in 2 NHL cases, is compatible with an association between HRV-5 and NHL, whether causal or not.

Base Sequence↗

PubMed2000

Increased immunoglobulin G, but not M, binding to endogenous retroviral antigens in HIV-1 infected persons.

The modes of interaction between products of human endogenous retroviral (HERV) sequences and the immune system are largely unknown. In HIV infected persons, an exogenous retrovirus adds further complexity to the situation. Therefore, 14 synthetic peptides with sequences derived from conserved regions of various endogenous retroviruses (ERVs) and from related exogenous retroviruses were used to search for IgG and IgM antibodies that bind to such antigens in 15 HIV-1 seropositive and 17 seronegative immunosuppressed patients. IgG binding to three peptides, namely, the C-terminal half of murine leukemia virus (MLV) capsid protein, the conserved portion of HERV-H transmembrane protein, and the Pol region of human mouse mammary tumor virus (MMTV)-like (HML3) sequence, was observed in both groups. Binding was, however, more frequent and more firm in HIV-1 positive samples (P<0.0001, Wilcoxon rank sum test). IgM binding to the same peptides showed no significant differentiation between the two groups of patients. Binding to both immunoglobulin isotypes was sometimes variable over time in both groups. No correlation of either IgG or IgM peptide binding with progression to AIDS in HIV-1 infected individuals was observed. Inhibition studies using analogous endogenous and exogenous retroviral peptides, including HIV-1, demonstrated specificity of the IgG antibodies for a narrow range of MLV- and MMTV-like retroviral antigens, and excluded cross-reactivity of antibodies to HIV-1 as a cause of these observations. Thus, unlike IgG, IgM binding to retroviral antigens was ubiquitous. It is suggested that anti-HERV IgM belong to a class of natural antibodies and might serve as primers in the mediation of humoral immune responses to more or less related exogenous retroviruses. Increased IgG binding in HIV-1 infected individuals could result from such priming, or reflect higher HERV antigen expression.

Amino Acid Sequence↗

PubMed2000

Activation of type I interferon system in systemic lupus erythematosus correlates with disease activity but not with antiretroviral antibodies.

The objective was to investigate the relation between serum levels of interferon-alpha (IFN-alpha), the activity of an endogenous IFN-alpha inducing factor (SLE-IIF), clinical and immunological disease activity as well as serum levels of antiretroviral antibodies in SLE. Serum levels of IFN-alpha were measured in serial sera from 30 patients sampled at different stages of disease activity (SLEDAI score). The SLE-IIF activity was measured by its ability to induce IFN-alpha production in cultures of normal peripheral blood mononuclear cells. Both serum IFN-alpha and SLE-IIF increased markedly at flare in serially followed patients. The SLEDAI score, levels of anti-dsDNA antibodies and IL-10 correlated positively, and complement components Clq, C3 and leukocytes correlated inversely with serum concentrations of IFN-alpha. The extent of multiple organ involvement correlated with serum IFN-alpha. No relation between concentrations of retroviral peptide binding antibodies and IFN-alpha or SLE-IIF activity was found. The close relationship between disease activity in SLE patients and IFN-alpha serum levels suggests that activation of the type 1 IFN system might be of importance in the disease process.

Adult↗

PubMed2000

Varieties of long-term outcome among patients in psychoanalysis and long-term psychotherapy. A review of findings in the Stockholm Outcome of Psychoanalysis and Psychotherapy Project (STOPP).

This paper reports the main findings of a large-scale study of subsidized psychoanalysis and long-term psychotherapy. More than 400 people in various phases, before, during and after subsidized psychoanalysis or long-term psychodynamic psychotherapy, were followed up for a period of three years with personal interviews, questionnaires and official statistics. Our analyses revealed progressive improvement the longer patients were in treatment--impressively strong among patients in psychoanalysis--on self-rating measures of symptom distress and morale. Improvement, however, was equally weak in both groups on a self-rating measure of social relations. Dosage factors (treatment duration and session frequency in combination) partly accounted for the outcome differences between those referred to psychoanalysis and those referred to long-term psychotherapy. Attitudes and ideals among therapists and analysts concerning the goals and means of psychotherapy were also associated with patient outcome, although in rather complex ways. A significant part of the outcome differences between patients in psychoanalysis and in psychotherapy could be explained by the adoption, in a large group of therapists, of orthodox psychoanalytic attitudes that seemed to be counterproductive in the practice of psychotherapy but not in psychoanalysis. It is suggested that this effect may be a negative transfer of the psychoanalytic stance into psychotherapeutic practice and that this may be especially pronounced when the attitudes are not backed up by psychoanalytic training.

Adult↗

PubMed1999

Development of an on-line coupling of liquid-liquid extraction, normal-phase liquid chromatography and high-resolution gas chromatography producing an analytical marker for the prediction of mutagenicity and carcinogenicity of bitumen and bitumen fumes.

A fast and fully automated system for the determination of polycyclic aromatic compounds (PACs) is described. The system has been developed to produce an analytical 'marker', correlating chemical characteristics (including PAC analysis) with mutagenicity and carcinogenicity. The products of interest are bitumen fumes, bitumen and other (heavy or even residual) oil products, regardless of their boiling range. Dimethyl sulphoxide (DMSO) extractables obtained from a flow-injection analysis (FIA) system are introduced on-line in a normal-phase liquid chromatographic (NPLC) system. Here, the PACs are separated from the DMSO and possible co-extracted heavy residual species. The final step incorporates on-line gas chromatographic analysis of the three-to-six-ring PAC fraction, followed by flame-ionisation detection for quantification. It was demonstrated that data obtained from samples in the distillate lubrication-oil range correlate well with data obtained from the manual DMSO-extraction method standardised by the Institute of Petroleum as IP346.

Carcinogenicity Tests↗