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Biomedical subjects

G Wadell

Publications and source records attributed to G Wadell.

At least 37 records · Page 2Linked to original sources
PubMed1998

A minority of seropositive wild bank voles (Clethrionomys glareolus) show evidence of current Puumala virus infection.

Bank voles (Clethrionomys glareolus) serve as the reservoir for Puumala (PUU) virus, the aetiologic agent of nephropathia epidemica. The animals are believed to be persistently infected and the occurrence of serum antibodies is usually taken as an evidence of active infection. We found serum antibodies to PUU virus in 42 of 299 wild bank voles captured in a PUU virus endemic area. PUU virus RNA was demonstrated in lung specimens of 11 of these 42 animals and in 2 of them antigen was also found. Thus in the lungs of 31 of 42 seropositive animals neither PUU virus RNA nor antigen was detected. In 2 of 257 seronegative animals, lung specimens showed presence of PUU virus antigen and RNA. Isolation of PUU virus from lung tissue was successful in all 4 antigen-positive bank voles but in none of 16 tested antigen-negative animals. In conclusion, only a minority of bank voles with serum antibodies to PUU virus showed evidence of current infection.

Amino Acid Sequence↗
PubMed1998

High prevalence of Chlamydia pneumoniae DNA in peripheral blood mononuclear cells in patients with cardiovascular disease and in middle-aged blood donors.

Nested polymerase chain reaction (nPCR) demonstrated the presence of Chlamydia pneumoniae-specific DNA in peripheral blood mononuclear cells (PBMC). PBMC samples were obtained from 103 consecutive patients (62 male, 41 female) aged 22-85 years (mean, 64) admitted for coronary angiography because of suspected coronary heart disease and from 52 blood donors (43 male, 9 female) aged 40-64 years (mean, 49). Of the 101 evaluable patients, 60 (59%) were identified by nPCR assay as C. pneumoniae DNA carriers; C. pneumoniae-specific microimmunofluorescence (MIF) serology confirmed exposure to the bacterium in 57 (95%) of the 60 nPCR-positive patients. Among the 52 blood donors, the nPCR assay identified 24 (46%) C. pneumoniae DNA carriers, all of whom were positive by C. pneumoniae-specific serology. Thirty-two patients (32%) and 23 blood donors (44%) were MIF antibody-positive but repeatedly nPCR-negative; Bartonella henselae- or Bartonella quintana-specific antibodies were not detected among any of these subjects. In this study, C. pneumoniae DNA was common in PBMC of patients with coronary heart disease and in middle-aged blood donors.

Adult↗
PubMed1998

Development of humoral cross-reactivity to the nucleocapsid protein of heterologous hantaviruses in nephropathia epidemica.

A hantavirus infection is followed by a prominent antibody response to the viral nucleocapsid protein. Antibodies from patients infected with one hantavirus cross-react to varying degrees with the nucleocapsid protein of other viruses of the genus. We studied the cross-reactivity in serially obtained blood samples from 17 patients with nephropathia epidemica, a European form of hemorrhagic fever with renal syndrome caused by Puumala virus. Recombinant truncated nucleocapsid protein (aa 1-117) of Puumala virus and four other hantaviruses, Hantaan, Seoul, Dobrava and Sin Nombre viruses, were used as antigens in an indirect ELISA. In most patients, an IgG response to the Puumala virus derived recombinant protein was detected within 2-8 days of onset of disease, remained high for 2-5 months, and declined gradually within 2-3 years. All patients had IgG antibodies cross-reacting with the nucleocapsid protein of Sin Nombre virus. The ratio of the ELISA values obtained with Sin Nombre vs. Puumala virus protein as antigen increased with time after onset of disease. To a lesser extent, cross-reacting IgG antibodies also occurred to Hantaan, Seoul, and Dobrava virus antigens. In the acute phase of the disease, two patients showed IgG antibodies to one or more of these viruses whereas 2-5 months later, 11 of 16 patients had IgG antibodies to all three viruses. IgM and IgA responses to the nucleocapsid protein of Puumala virus were transitory and cross-reactivities were weak. In conclusion, after onset of nephropathia epidemica the IgG response to the Puumala virus nucleocapsid protein was associated with a gradually increasing cross-reactivity to the nucleocapsid protein of heterologous hantavirus. Our findings have implications for the interpretation of serological data, both in the diagnostics of nephropathia epidemica and in seroprevalence studies.

Adult↗
PubMed1997

Fiber genes of adenoviruses with tropism for the eye and the genital tract.

We have characterized the fibergenes of adenovirus type 19p (Ad19p), Ad19a, and Ad37 by sequencing. The fiber genes of Ad19a and Ad37 are identical and only five amino acids differ comparing Ad19a/Ad37 with Ad19p. Based on the translated sequences we calculated the isoelectrical points (Ips) and found that the fiber knobs of Ad19p, Ad19a, and Ad37 together with Ad8 display the highest Ips of all so far characterized. Two regions within the fiber knob with unusually basic characteristics have been identified. Sequence alignments revealed that the corresponding regions in other fiber knobs are highly antigenic in pepscan analysis and of importance for hemagglutination. Only two positions differ in the knobs comparing Ad19a/Ad37 with Ad19p. Hence, either of these or both amino acid residues should be expected to be responsible for the observed differences in hemagglutination between Ad19p and Ad19a/Ad37. Moreover, we have found two amino acids (Ala227 and Lys252) that are unique in their respective position in Ad19p, Ad19a, Ad37, and Ad8. Three amino acids (Lys236, Lys240, and Asn251) are unique in their respective position in Ad19a and Ad37, that manifest a tropism for the genital tract. All five amino acids colocalize within one of the two basic regions.

Adenoviruses, Human↗
PubMed1997

The first human isolate of Puumala virus in Scandinavia as cultured from phytohemagglutinin stimulated leucocytes.

A virus isolate was recovered from blood leucocytes of a patient with nephropathia epidemica (NE). Leucocytes were isolated from EDTA-blood by dextran sedimentation and cultured on monolayers of Vero E6 cells in the presence of phytohemagglutinin (PHA) in roller tubes during the first 72 hours of incubation followed by rolling culture for three weeks in total. Thereafter the first subculture was done in a plastic flask and afterward at at least 6 week intervals. Antigen was first detected after 6 months and 2 weeks of culture. When tested by monoclonal antibodies and patient sera the isolate had the characteristics of a PUU virus. PCR amplification using PUU-specific primers and subsequent partial sequencing of the S and M segments revealed that the Umeå/305/human/95 virus differs from the Finnish PUU Sotkamo rodent prototype virus and is similar but not identical to rodent strains of PUU virus acquired from the same region as the patient isolate. It is we concluded that the first human isolate of the etiologic agent of NE in Scandinavia was recovered from blood leucocytes stimulated with PHA by long-term culture in Vero E6 cells. The isolate belongs to the PUU serotype of hantaviruses as shown by its serologic profile and partial sequencing data.

Adult↗
PubMed1997

Hydropathic characteristics of adenovirus hexons.

The complete nucleotide sequence and the predicted amino acid sequence of the adenovirus type 7 hexon gene were determined. The hydropathy of the hexon proteins from human adenovirus types 2, 3, 4, 5, 7, 12, 16, 40, 41, and 48, bovine adenovirus type 3, murine adenovirus type 1, and avian adenovirus types 1 and 10 was analysed. The presence of purines and pyrimidines in the second position of the codons was correlated to hydrophilicity and hydrophobicity, respectively. Comparison of the hydrophilicity plots of eight hexons showed seven hypervariable regions to be distributed on the surface. A large portion of the hypervariable regions manifests hydrophilicity. The strength of the surface charge accumulated on the hydrophilic and hydrophobic regions correlated to the tissue tropism of the different adenovirus types. Analysis of codon usage for adenovirus hexons showed that among synonymous codons those with cytidine in the third position were preferably used to a great extent. Analysis of the nucleotide and amino acid sequence pair distances and the phylogenetic tree of 14 hexon proteins showed members of subgenera B, D and E to be closely related, especially Ad4 and Ad16, and subgenus A to be closely related to subgenus F.

Adenoviruses, Human↗
PubMed1997

Acetowhitening of the cervix and vulva as a predictor of subclinical human papillomavirus infection: sensitivity and specificity in a population-based study.

OBJECTIVE: To evaluate acetowhite changes of the cervix and vulva as a predictor of human papillomavirus (HPV) infection. METHODS: In this population-based study all women aged 19, 21, 23, and 25 years and registered as living in a primary health care area within the city of Umeå, Sweden were eligible for inclusion. Each participant underwent a gynecologic examination with sampling of epithelial cells for HPV-DNA detection and Papanicolaou smear. Colposcopy was performed 5 minutes after application of 5% acetic acid. A two-step polymerase chain reaction (PCR) technique was employed for HPV-DNA detection. RESULTS: Colposcopy and sampling of epithelial cells could be performed in 535 women. The sensitivity of detection of HPV infection by the acetowhitening of the cervix was 22% (95% confidence interval [CI] 18%, 26%). The specificity of detection of HPV infection by the acetowhitening of the cervix was 90% (95% CI 87%, 93%). The sensitivity of detection of HPV infection by cytology was 13% (95% CI 10%, 16%), and the specificity was 99% (95% CI 98%, 100%). The combination of acetowhitening and cytology did not improve the diagnostic value. CONCLUSION: Acetowhitening of the cervix and vulva has low sensitivity as a predictor of HPV infections as determined by PCR.

Acetic Acid↗
PubMed1997

Increased plasma levels of soluble CD23 in haemorrhagic fever with renal syndrome; relation to virus-specific IgE.

In 15 consecutive patients hospitalized with nephropathia epidemica, a European form of haemorrhagic fever with renal syndrome (HFRS) caused by Puumala virus, plasma concentrations of soluble CD23 (sCD23) and Puumala virus-specific IgE were determined. In the acute phase of illness, 11/15 patients had increased sCD23 levels (> 91 U/ml), whereas in convalescence, values of 8/10 patients were normalized. Maximal sCD23 values were correlated to maximal concentrations of Puumala virus-specific serum IgE (r = 0.597; P = 0.025). The results are compatible with a known ability of sCD23 to augment IgE production.

Adult↗
PubMed1997

Rapid diagnosis of respiratory Chlamydia pneumoniae infection by nested touchdown polymerase chain reaction compared with culture and antigen detection by EIA.

Chlamydia pneumoniae is a common cause of respiratory tract infection and community-acquired pneumonia. During an extensive outbreak of C. pneumoniae in northern Sweden, 319 respiratory samples from 129 persons were collected. Sputum, throat, and nasopharyngeal samples were obtained and analyzed by nested touchdown polymerase chain reaction (PCR), EIA, and culture in Hep-2 and McCoy cells. Serology was performed by complement fixation and microimmunofluorescence tests. By PCR, 30 patients were diagnosed with C. pneumoniae compared with 26 positive by EIA and 23 by culture. The finding of C. pneumoniae in the respiratory samples was accompanied by serology indicating acute infection in 26 (96%) of 27 patients for whom adequate sera were available. Nested PCR was sensitive and reliable for diagnosing acute respiratory C. pneumoniae infection. Sputum samples had the highest diagnostic efficacy, and the nested type of PCR was superior to one-step PCR. EIA and culture were less sensitive than nested PCR.

Acute Disease↗
PubMed1997

Failure to detect Chlamydia trachomatis in cell culture by using a monoclonal antibody directed against the major outer membrane protein.

Two commercially available monoclonal antibodies for cell culture confirmation of Chlamydia trachomatis were compared in two prospective studies and one large retrospective study. In total, more than 33,000 genital specimens were cultured in parallel and stained with both antibodies, one of which was directed against the major outer membrane protein (MOMP) and one of which was directed against the lipopolysaccharide (LPS). We found the anti-LPS-based assay to be more sensitive and as specific as the anti-MOMP-based assay for C. trachomatis cell culture confirmation of genital specimens.

Antibodies, Bacterial↗
PubMed1997

Serological diagnosis of hantavirus infections by an enzyme-linked immunosorbent assay based on detection of immunoglobulin G and M responses to recombinant nucleocapsid proteins of five viral serotypes.

Worldwide, hantaviruses cause more than 100,000 human infections annually. Rapid and accurate methods are important both in monitoring acute infections and for epidemiological studies. We and others have shown that the amino termini of hantavirus nucleocapsid proteins (Ns) are sensitive tools for the detection of specific antibodies in hantavirus disease. Accordingly, we expressed truncated Ns (amino acids 1 to 117) in Escherichia coli from the five hantaviruses known to be pathogenic to man; Hantaan (HTN), Seoul (SEO), Dobrava (DOB), Sin Nombre (SN), and Puumala (PUU) viruses. In order to obtain pure antigens for use in an enzyme-linked immunosorbent assay (ELISA), the recombinant proteins were purified by polyhistidine-metal chelate affinity chromatography. Polyclonal animal antisera and a panel of serum specimens from hantavirus-infected individuals from Scandinavia, Slovenia, Russia, Korea, China, and the United States were used to evaluate the usefulness of the method. With both human and animal sera, it was possible to designate the antibody response into two groups: those with HTN, SEO, and DOB virus reactivity on the one hand and those with SN and PUU virus reactivity on the other. In sera from Scandinavia, European Russia, and the United States, the antibody response was directed mainly to the PUU and SN virus group. The sera from Asia reacted almost exclusively with the HTN, SEO, and DOB types of viruses. This was true for both the immunoglobulin M (IgM) and IgG antibody responses, indicating that this type of discrimination can be done during the acute phase of hantavirus infections. Both the HTN, SEO, and DOB virus and the PUU and SN virus types of antibody response patterns were found in patients from the Balkan region (Solvenia).

Animals↗
PubMed1997

The associations between risk behaviour and reported history of sexually transmitted diseases, among young women: a population-based study.

The aim of this study was to determine the associations between risk behaviour and women's reported sexually transmitted diseases (STDs). All the women aged 19, 21, 23 and 25, residing in a specified housing area, were invited to answer a questionnaire regarding their sexual behaviour, smoking and alcohol consumption and previous history of STD. Of the 611 women participating, one out of 4 women had a history of at least one STD. In an univariate analysis, self-reported STD was found to be related to age, having more than 4 lifetime sexual partners, having practised intercourse at first date, inconsistent use of condoms, alcohol consumption of more than 3 bottles of wine per month and smoking. These factors were, however, not independent of each other and when subjected to a multivariate logistic regression analysis 2 factors, i.e. the lifetime number of sexual partners (more than 4 partners vs one; OR 7.94, (3.41-18.50)) and coitus on first date (practised more than once vs never, OR 2.99 (1.55-5.78)) emerged as independently associated with a previous STD.

Adult↗
PubMed1997

Prevalence of serum antibodies to hantaviruses in northern Sweden as measured by recombinant nucleocapsid proteins.

An enzyme-linked immunosorbent assay (ELISA) based on recombinant nucleocapsid protein (rN delta) (aa 1-117) of Hantaan, Seoul, Dobrava, Sin Nombre and Puumala hantaviruses was used to determine the prevalence of antibodies among randomized and stratified individuals from northern Sweden. In total, 137/1533 individuals (8.9%) had specific serum IgG antibodies to Puumala virus, the only hantavirus known to occur in the region. The prevalence of antibodies to Puumala virus (8.9%) was determined to be higher than previously reported (5.4%) in the same serum material, by use of immunofluorescence assay. As expected, sera reactive to Puumala virus rN delta did frequently cross-react with Sin Nombre virus protein. Unexpectedly, 21/1533 (1.4%) individuals recognized the Sin Nombre virus rN delta exclusively. Another 8 subjects showed reactivity in the ELISA to Hantaan, Seoul, or Dobrava virus-derived rN delta but not Puumala virus or Sin Nombre virus rN delta. The present demonstration in some individuals of antibodies specifically recognizing the Sin Nombre, Dobrava, Hantaan and Seoul virus protein justifies an awareness of the possibility that hantaviruses antigenically different from Puumala virus might occur in the region.

Adult↗
PubMed1997

High prevalence of hantavirus antibodies in bank voles (Clethrionomys glareolus) captured in the vicinity of households afflicted with nephropathia epidemica.

Puumala virus, the causative agent of nephropathia epidemica (NE), occurs endemically in Europe and is spread mainly by the bank vole (Clethrionomys glareolus). In the vicinity of each of four households afflicted with NE, we studied rodents with regard to population density and prevalence of Puumala virus-specific antibodies. For each case area, a control area was randomly selected 10 km away, without regard to the presence of human settlement. During 6,000 trap nights, 328 rodents were caught, of which 299 were C. glareolus. The mean rodent densities of case and control areas were 6.6 and 3.7 animals per 100 trap nights (P < 0.001). The prevalence of serum antibodies was 15.9% in case areas compared with 5.6% in control areas (P < 0.05). In three of the case areas, where NE had occurred 3-10 weeks before trapping, the rodent density and seroprevalence were much higher than in the fourth area, where NE occurred 38 weeks before trapping. In conclusion, C. glareolus seropositive for Puumala virus occurred more frequently near households afflicted with NE than in control areas 10 km away.

Adult↗
PubMed1996

A prospective study on the risk of cervical intra-epithelial neoplasia among healthy subjects with serum antibodies to HPV compared with HPV DNA in cervical smears.

To estimate the risk of developing cervical intra-epithelial neoplasia (CIN) among women exposed to human papillomavirus (HPV) type 16, we performed a prospective study in a population-based cohort of more than 15,000 women followed for 34.9 months. Seventy-four women developed CIN during follow-up and were matched for age, time of sampling and area of residence with 148 women who remained CIN-free during follow-up. The blood samples taken at enrollment were tested for serum antibodies to HPV types 16, 18 and 33 capsids. Cervical smears or biopsies were analyzed for the presence of HPV DNA by nested PCR using HPV general primers and by HPV 16- and 18-type-specific PCR HPV serology and HPV-PCR were in good agreement, particularly when the blood sample and the Pap smear were taken less than 6 months apart. HPV DNA was found in 88% of cases and 4% of controls, whereas HPV 16 DNA was present in 44% of cases and in 1 of 142 controls. HPV-16-seropositive women had a 3-fold increased risk of developing CIN. The risk was highest among women younger than 35 years of age, of whom an estimated 3.4% of HPV-16-seropositive and 0.5% of seronegative women developed CIN. Since the risk associated with HPV-16 seropositivity (a measure of past or present infection) was 35-fold lower than that of HPV DNA (present infection), most infections appear to be eliminated before CIN develops. In conclusion, HPV 16 infection does confer an excess risk of CIN development, and HPV DNA detection has a high predictive value for the presence of high-grade CIN.

Adult↗
PubMed1996

Sequence analysis of the E3 region and fiber gene of human adenovirus genome type 7h.

Adenovirus type 7h is currently the predominant virulent genome type of serotype 7 isolated in Argentina, Chile, and Uruguay in association with severe infantile pneumonia. In order to characterize possible molecular determinants of pathogenicity, the nucleotide sequence of a 5904-bp fragment (76 to 93 mu) containing the entire E3 region and the fiber gene of Ad7h was established. The organization of the ORFs within the E3 region was similar to that reported for the prototype strains of Ad7 and Ad3. A comparison of the nucleotide and amino acid sequences of all ORFs revealed a higher homology between Ad7h and Ad7p than between Ad7h and Ad3 for 12.0K and 16.1K, whereas the 15.3K ORF and the adjacent fiber gene were strikingly more homologous to those of Ad3 (99.5 vs 81.1% and 98.2 vs 66.6%, respectively). The equivalent to ORF 7.7K in Ad7p was missing in Ad7h due to a deletion and a mutation affecting the start codon (ATG-->ATT). Although the hemagglutinin of the Ad7h fiber could not be characterized due to its lack of activity on monkey erythrocytes, our results indicate that Ad7h is an intermediate strain 7-3.

Adenovirus E3 Proteins↗
PubMed1996

Molecular epidemiology of adenovirus acute lower respiratory infections of children in the south cone of South America (1991-1994).

A collection of 165 adenovirus strains isolated from nasopharyngeal aspirates of children hospitalized for acute lower respiratory infection in Argentina, Chile, and Uruguay between 1991 and 1994 was studied by restriction enzyme analysis (work performed in the Department of Virology, University of Umeå). Of the isolates, 71% (n = 117) were identified as members of subgenus B. Of these, 101 (61.2%) corresponded to genome type 7h, four (2.4%) to genome type 3p2, four (2.4%) to genome type 11a, one (0.6%) to genome type 7b, and one (0.6%) to genome type 7c. Two isolates that were neutralized as serotype 3 and four isolates that were neutralized as serotype 7 exhibited novel BamHI cleavage profiles corresponding to three new genome types denominated 3x, 7i, and 7j. Subgenus C members represented 28.5% of all typed isolates. Five different genome types of Ad1, seven genome types of Ad2, and three genome types of Ad5 were identified of, which two, two, and one, respectively, were found to correspond to new DNA variants. Only one isolate (0.6%) corresponded to Ad4 of subgenus E. Ad7h was isolated from 17 of the 18 fatal cases recorded among the patients included in the study.

Acute Disease↗