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G Wadell

Publications and source records attributed to G Wadell.

At least 55 records · Page 3Linked to original sources
PubMed1996

Molecular epidemiology of adenovirus types 3 and 7 isolated from children with pneumonia in Beijing.

One hundred fifty strains of adenovirus sero-types 3 (Ad3) and 7 (Ad7) were analyzed. The viruses were isolated from patients, the majority of whom had pneumonia, from central and sub-urban Beijing over a 33-year period (1958-1990). Genomic analysis of DNA extracted from 74 strains of Ad3 and 76 strains of Ad7, with four to five restriction endonucleases (REs), revealed the presence of four and eight genome types, respectively: Ad3a2, Ad3a4, Ad3a5, Ad3a6 and Ad7p1, Ad7a1, Ad7a4, Ad7b, Ad7b1, Ad7d, Ad7d1, and Ad7g. Ad7b1 was the most recently identified genome type. The restriction patterns obtained from 19 representatives of Ad7 genome types after cleavage of the DNA with 12 REs are shown. Ad3a2 first appeared in 1962, and predominated from 1983 to 1988. Ad3a4 was the main causative agent of pneumonia in 1982. Ad3a2 and Ad3a4 are closely related and have 97% pairwise comigrating restriction fragments (PCRF). Ad7d predominated over a period of 11 years (1980-1990). It has 98% PCRF with Ad7b. Ten pairs of strains isolated from different specimens of the same patients were all concordant.

Adenoviridae Infections↗
PubMed1996

Detection of human papillomavirus in cervical intra-epithelial neoplasia, using in situ hybridization and various polymerase chain reaction techniques.

One hundred and forty-eight randomly chosen neutral-buffered formaldehyde-fixed cervical biopsies in which cervical intra-epithelial neoplasia (CIN) I-III had been diagnosed were tested for HPV (human papilloma virus) DNA by in situ hybridization (ISH) and polymerase chain reaction (PCR). For ISH, we utilized a biotinylated panprobe and type-specific, genomic probe sets. For PCR, we used the general primers GP5/GP6 and their recently described, elongated version GP5+/GP6+, and included the modification of hot-start PCR. Amplified DNA was detected by gel electrophoresis and slot blot hybridization. The positivity rate of ISH was 59% for all biopsies and 69%, 62% and 46% for CIN I, II and III, respectively. The sensitivity of GP5/GP6 was 74% with cold-start PCR and 78% with hot-start PCR. When GP5+/GP6+ was used, the sensitivity increased to 89% with cold-start PCR and to 95% with hot-start PCR. Based on the most sensitive PCR technique, HPV detection was 93%, 95% and 96% in CIN I, II and III, respectively. The number of HPV types decreased with the severity of the lesion, and HPV 16 was the predominant type. Multiple HPVs were rare and almost all HPV-positive cases could be typed. ISH and slot blot hybridization correlated well regarding HPV typing specificity. Our results confirm that distinct HPV types are present in a high proportion of cases of CIN. The sensitivity of ISH is lower than that of PCR. Furthermore, the modified general primers GP5+/GP6+ give a higher yield than GP5/GP6, while hot-start PCR increases sensitivity even further.

Adolescent↗
PubMed1996

A major antigenic domain for the human humoral response to Puumala virus nucleocapsid protein is located at the amino-terminus.

Nephropathia epidemica (NE), the major form of hemorrhagic fever with renal syndrome in Europe, is caused by the hantavirus serotype Puumala (PUU). The PUU virus nucleocapsid protein (N) has been shown to be highly immunogenic both in laboratory animals and in man. We aimed to locate domains important in humoral immune reactivity and to use this information to develop a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for serological diagnosis of NE. Escherichia coli poly-histidine fusion protein expression vectors containing over-lapping gene segments encoding the PUU virus N (PUU rN) were constructed. The resulting gene products were examined by immunoblots and ELISA with polyclonal and monoclonal antibodies. The dominating antigenic region of PUU rN was located between amino acids (aa) 7 and 94. A recombinant fusion protein containing aa 7-137 of PUU virus N (PUU rN delta 5) was used for the detection of specific IgG and IgM responses in NE. ELISA based on PUU rN delta 5 was found to have equal sensitivity and specificity as compared to the full length recombinant PUU rN by ELISA, for both acute serological diagnosis of NE and for seroepidemiological screening purposes. Furthermore, this protein is easier to handle than full length PUU rN due to its higher solubility in aqueous solutions.

Animals↗
PubMed1996

The clinical usefulness of a Puumalavirus recombinant nucleocapsid protein based enzyme-linked immunosorbent assay in the diagnosis of nephropathia epidemica as compared with an immunofluorescence assay.

BACKGROUND: Nephropathia epidemica (NE), a hemorrhagic fever with renal syndrome (HFRS) predominantly encountered in northern Europe, is a febrile disease, commonly associated with acute renal impairment. A rapid and reliable serological diagnosis is required to differentiate NE from other acute febrile illnesses in endemic areas. OBJECTIVE: To evaluate a Puumala (PUU) virus recombinant nucleocapsid protein (rN) based enzyme-linked immunosorbent assay (ELISA) for the serological diagnosis of NE as compared with an immunofluorescence assay (IFA) in a clinically relevant patient sample. STUDY DESIGN: During a four-month period, 618 serum samples from 512 patients with an illness suggestive of NE, sent to the Department of Clinical Virology for serological analysis, were included in the study. All sera were tested by PUU rN ELISA for presence of specific IgG, IgM and IgA antibodies and by IFA using PUU virus infected cells as antigen for presence of IgG and IgM antibodies. Patients with discordant results by IFA and rN ELISA were further serologically and/or clinically evaluated to assess the probability of NE. RESULTS: Compared to IFA, the specificities of the IgM and IgG rN ELISA were 100% and the corresponding sensitivities were 94.0%. The positive and negative predictive values of the PUU IgM rN ELISA in diagnosing NE infection was 100 and 98.6%, respectively. The positive predictive values for present NE infection of IgG rN ELISA and IFA were 68.3 and 71.4%, respectively. The positive predictive value of IgA rN ELISA was 95.8% and the negative 92.7%. CONCLUSIONS: The demonstration of specific IgM by rN ELISA is a highly specific and reliable method for the serological confirmation of NE. Detection of IgG antibodies by rN ELISA or IFA has a low predictive value to diagnose NE in an endemic area. The diagnostic value of IgA determination is in between IgM and IgG determinations.

Journal Article↗
PubMed1996

Nested PCR assays with novel primers yield greater sensitivity to Tanzanian HIV-1 samples than a commercial PCR detection kit.

To investigate the efficacy of the SK431/SK145 primer pair and two nested primer assays in amplifying African HIV-1 samples, a total of 35 Tanzanian PBMC samples were examined. These were assayed by two HIV-1 specific nested in-house PCR assays and a commercial HIV-1 PCR kit (GeneAmp) using SK431/SK145 as the primer pair. One of the nested PCR assays has been evaluated previously (old assay), whereas the modified assay was constructed from the HIV-1 sequence alignment released in August 1993. The modified nested primer assay showed increased sensitivity in the gag and env regions compared to the old nested primer assay. However, both the old and the modified nested primer assays displayed higher sensitivity for the detection of Tanzanian HIV-1 proviruses than the GeneAmp assay. When two regions were used (gag and env) as targets for the amplification, the modified nested primer assay detected 97.1% (34/35) of the proteinase K lysed samples, compared to 68.6% (24/35) using the SK431/SK145 primer pair (P < 0.01**). The results indicate that the SK431/SK145 primer pair may be less suitable when HIV-1 samples from Africa are analysed. The results also show that continuous modification of primer sequences can improve and maintain high sensitivity for the detection of highly divergent HIV-1 strains.

DNA Primers↗
PubMed1996

Nonradioisotopic detection and typing of human papillomaviruses by use of polymerase chain reaction and single-strand conformation polymorphism.

The polymerase chain reaction (PCR), used to detect human papillomavirus (HPV), is finding increasing applications in clinical laboratories. The standard method of analysis to detect amplified PCR products is ethidium bromide gel electrophoresis combined with labor intensive blot hybridization. In this study, we describe single-strand conformation polymorphism (SSCP) to detect and genotype simultaneously general primer GP5+/GP6+ amplified HPV DNA using semiautomated electrophoresis on polyacrylamide gels (PAGE) combined with sensitive silver staining. To establish a standard for the band patterns of the various HPV types, we used HPV plasmid DNA, which allowed us to distinguish HPV 6, 11, 16, 18, 31, 33, 35, 45, 51, 52, 56, and 58, covering the most frequently recognized types. All the types tested are separated from each other, demonstrating diverse band patterns, HPV 16 being the most distinct. We also investigated PCR-SSCP for HPV detection and typing of 86 cervical biopsies diagnosed as cervical intraepithelial neoplasia (CIN) I-III and known to be HPV positive by PCR-slot blot hybridization and in situ hybridization. The correlation with SSCP was 91% for in situ hybridization and 98% for PCR-slot blot hybridization. SSCP is reproducible and specific. Its sensitivity is comparable to slot-blot hybridization. The interval to SSCP is approximately 2 h after PCR compared with several days' work when using conventional blot hybridization. We concluded that SSCP may be more advantageous than other PCR-based typing technologies.

Adolescent↗
PubMed1996

Epitopes and hemagglutination binding domain on subgenus B:2 adenovirus fibers.

The adenovirus fiber serves as a ligand between the virus and the host cell receptor and manifests hemagglutination (HA) activity and antigenic domains. We have screened both the antigenic and immunogenic epitopes on the adenovirus fibers of subgenus B:2 by using recombinant fiber proteins (rfibers) expressed in Escherichia coli, synthesized peptides (P1 to P8), and the corresponding antisera. The results indicated that P4 (amino acids [aa] 201 to 220), P5 (aa 231 to 250), and P7 (aa 275 to 295) presented both antigenic and immunogenic epitopes in adenovirus type 11 prototype (Ad11p), Ad34a, and Ad11a fibers. P6 (aa 251 to 270) presented both epitopes in Ad11a fiber but only an antigenic epitope in other fibers. The C-terminal 20 amino acids of the fiber, corresponding to P8, manifested an epitope of low-level immunogenicity. P5, localized at the N-terminal aa 231 to 250, displayed an epitope that reacted with fibers of all the members of subgenus B analyzed. The rfibers of Ad11p and Ad34a displayed HA activity with monkey erythrocytes, though those of Ad11a did not. Mutagenesis of the rfibers revealed that neither the fragment replacements, 11p20211a, llp26011a,and 11a28011p, nor the Ad11p rfiber with the substitutions of Tyr-260-->H (Tyr260H)and Arg279Q displayed HA activity. The Ad11a fiber knob was sensitive to proteolytic digestion, whereas that of Ad11p was resistant. The results demonstrated that the decisive HA binding domain was presented at aa 260 to 280 and was conformation dependent. Nearby amino acids, aa 283 and 284, may also affect the HA function.

Adenoviridae↗
PubMed1996

Hantavirus antigen detection using human serum immunoglobulin M as the capturing antibody in an enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was developed to detect different hantavirus antigens in cell culture; i.e. Puumala (PUU), Hantaan (HTN), and Dobrava (DOB) viruses. The assay was based on binding human serum immunoglobulin M (IgM) antibodies to the solid phase by use of goat anti-IgM antibodies. The captured IgM antibodies were present in the acute phase serum from two patients: one infected in Sweden and the other in Bosnia. Antigens being bound to the solid phase by the human anti-PUU and anti-DOB/HTN IgM antibodies were detected by a broadly reacting polyclonal rabbit anti PUU-recombinant nucleocapsid protein antiserum. The IgM isotype was proven to be at least five times more efficient than IgG when used as the capturing antibody. The sensitivity of the PUU antigen ELISA was approximately 0.5 ng/ml, as measured by titration with a PUU recombinant nucleoprotein antigen. Cell-associated PUU antigen in tissue culture was seen after 48 hr by the PUU-ELISA and after 96 hr by immunofluorescent assay. When tested for capacity to discriminate between PUU, DOB, and HTN viruses, significant differences were found: the Swedish serum detected PUU antigen at high titers, whereas no reactivity was found against DOB and HTN; the Bosnian serum detected both DOB and HTN at high titers but had a low reactivity to PUU. The method was also tested for its usefulness in detecting PUU antigen in bank vole (clethrionomys glareolus) lungs. Of 59 animals captured from the surroundings of patients with nephropathia epidemica, three became positive with a high activity in the PUU-ELISA, but with low reactivity in the DOB/HTN-ELISA. It is concluded that a sensitive ELISA has been developed to detect different hantaviruses in cell culture and lungs of bank voles.

Animals↗
PubMed1996

Detection of homologous DNA sequences in animal adenoviruses by polymerase chain reaction.

A primer pair originally designed for the universal detection of human adenovirus (HAV) serotypes of all subgenera was modified then tested and found feasible for the detection of different bovine, ovine, and porcine adenovirus (BAV, OAV, and PAV, respectively) serotypes. Apparently, in the examined viruses, parts of the DNA sequence coding for the basal part of the hexon protein are conserved enough for being applicable in polymerase chain reaction (PCR) as primers. Positive amplification could be obtained even from the so-called subgroup 2 BAVs, which viruses do not cross react with HAVs or subgroup 1 BAVs in Southern hybridisation.

Adenoviruses, Human↗
PubMed1995

Can a test for E6/E7 transcripts of human papillomavirus type 16 serve as a diagnostic tool for the detection of micrometastasis in cervical cancer?

Tissue from 11 cases of cervical cancer positive for human papillomavirus (HPV) type 16 DNA and 69 pelvic lymph nodes from the same patients were examined for HPV 16 DNA and mRNA from the E6/E7 genes. Five of the tumors were squamous, 3 adeno- and 3 adenosquamous carcinoma. From the primary tumors and the extirpated lymph nodes DNA and RNA or mRNA was subjected to PCR and RT-PCR. Three transcription profiles (only E6*I, E6*I and E6*II or full-length E6-E7 plus both of the spliced transcripts) were found in all of the 11 HPV 16 DNA-positive primary tumors. From the total of 69 lymph nodes analyzed 28 were positive for mRNA. HPV 16 DNA was found in 7 additional samples. Cytokeratin was found in 19 of these lymph nodes, indicating epithelial origin of tumor cells. Only 1 patient had 2 metastases evidenced by histology. These were both positive for HPV DNA and mRNA. The finding of HPV DNA, mRNA and cytokeratin in lymph nodes of patients with cervical cancer should be an indication of lymphogenically driven micrometastases of the tumor. The HPV mRNA assay should offer higher specificity than the DNA test since mRNA can be found in live cells only, while HPV DNA also can originate from dead cell material sequestered in the lymph nodes.

Adult↗
PubMed1995

The morphogenesis of a Chinese strain of HIV-1 forming inclusion bodies in Jurkat-tat III cells.

A rapid/high replicative strain of human immunodeficiency virus type 1 (HIV-1) (BC9101) was isolated directly in the Jurkat-tat III cell line from a Chinese patient with AIDS. The thin-section electron microscopy was performed and revealed high efficiency of replication of BC9101 with some unusual biological properties. Many vacuoles, most of them filled with HIV particles, were found close to the nucleus. Double-cored virions and double budding were frequently observed in the vacuoles and at the vacuolar membrane. Virus particles matured by budding both into intracytoplasmic vacuoles and through the plasma membrane. Inclusion bodies of varying sizes, some consisting of thousands of HIV particles, were found in the cytoplasm. All the illustrated features describing formation of inclusion bodies were compatible with the observation that HIV particles were assembled at and budded from the cytoplasmic vacuole membrane. They were then released from the membrane into the vacuoles, and subsequently, the maturation occurred. Some of the vacuoles accumulated to such a high number of mature virus particles that inclusion bodies were formed. During the disintegration of the cells, the inclusion bodies surrounded by the vacuolar membrane were released from the cells. The nucleotide sequence of the vpu gene of BC9101 was investigated and indicated that the unusual biological properties may due to the lack of a start codon for translation of the vpu protein.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Highly heterogeneous fiber genes in the two closely related adenovirus genome types Ad35p and Ad34a.

Two adenovirus isolates from urine, Ad35p (from a bone marrow recipient) and Ad34a (from a hemorrhagic cystitis patient), were compared regarding their fiber gene organization and hemagglutinating capacity. The fiber serves as the ligand between the virus capsid and the host cell receptor. The Ad35p fiber gene encoded a 323-amino-acid protein, and the Ad34a fiber gene a 325 amino acid protein. The two fibers manifested 62.4% overall amino acid sequence homology, the differences predominantly occurring within the knob region where sequence homology was only 49.5%. The knob region of Ad34a was virtually identical to that of Ad11p which also causes hemorrhagic cystitis. Unlike all other known subgenus B adenoviruses, in the Ad35p fiber an asparagine constituted the C-terminus. Although both Ad34a and Ad35p viruses can hemagglutinate monkey erythrocytes, the hemagglutination inhibition test showed them to differ from each other in the epitopes expressed on the fibers.

Adenoviruses, Human↗
PubMed1995

Comparison of the kinetics of Puumala virus specific IgM and IgG antibody responses in nephropathia epidemica as measured by a recombinant antigen-based enzyme-linked immunosorbent assay and an immunofluorescence test.

Immunoglobulin M and G (IgM and IgG) responses were followed up to 6 months in patients with nephropathia epidemica (NE) by an enzyme-linked immunosorbent assay (ELISA) using a recombinant Puumala virus (PUU) nucleocapsid protein as antigen and an immunofluorescence test (IF) using PUU infected, acetone-treated cells as antigen. The recombinant protein was produced by cloning and expressing the nucleocapsid encoding gene of PUU as a polyhistidine fusion protein in Escherichia coli. The product was purified over a metal chelating ion affinity column. On admission, all 17 patients had an IgM response by both methods. The IgM titers decreased significantly by both methods 3 months after onset (ELISA P < 0.05 and IF P < 0.05). Four of six still had detectable IgM, however at low levels, after 6 months. Presence of specific IgG differed significantly on admission between the two methods: by ELISA 8 of 17 had detectable specific IgG, whereas by IF 15 of 17 had specific IgG (P < 0.02). There were 10 significant titer rises between acute and convalescent serum samples in the same patients by both methods. It is concluded that the IgG antibody response differs in the early phase of NE as measured by a method using a recombinant PUU nucleocapsid protein and a method using PUU infected acetone-treated cells as antigens. Furthermore, the results suggest that it is of importance to rely on specific IgM for serodiagnosis of NE during the acute phase.

Acute Disease↗
PubMed1995

Human papillomavirus infection is transient in young women: a population-based cohort study.

The prevalence of human papillomavirus (HPV) infection in cervical cell scrapes from a cohort of 276 young women was determined by a general two-step polymerase chain reaction. HPV infection fluctuated among young women during a 2-year interval. The total prevalence of HPV infection decreased from 21% to 8.3%. The most prevalent HPV types at enrollment were HPV-16 (3.3%) and HPV-6 (2.9%). At follow-up, the most common type was HPV-16 (2.9%), while no HPV-6 was detected. In 2 women only, the same HPV type persisted. Regression of HPV infection was found in 80% of the women. A new HPV type-specific infection was detected in 7.2% of the women and was independently associated with a new sex partner or an abnormal smear since enrollment.

Adult↗
PubMed1995

The silent suffering women--a population based study on the association between reported symptoms and past and present infections of the lower genital tract.

OBJECTIVES: To assess the prevalence of lower genital tract symptoms and the association between reported symptoms and past and present signs of sexually transmitted diseases (STD) in young women. DESIGN: All women belonging to the 19-, 21-, 23- and 25-year age cohorts and living in the catchment area of the community health centre, were invited by mail to take part in a population-based study. The participants answered a structured questionnaire and a gynaecologic examination was performed. Samples for wet smear, cervical Pap smear, HPV DNA determination and Chlamydia trachomatis culture were taken at the gynaecologic examination. The presence of genital warts was noted. A blood sample was analysed for antibodies against C trachomatis and HSV-2. SETTING: The community health care centre was located in Umeå, a city in Northern Sweden. RESULTS: Of the 886 women who were eligible, 611 (70%) participated in the investigation. One out of four women reported symptoms from the lower genital tract. The most commonly reported symptoms were itching, followed by discharge, and soreness. The most commonly reported STD was C trachomatis (15%). The most prevalent present STD was HPV infection (20%) whereas C trachomatis infection could be isolated from 2.7% of the women. Antibodies against C trachomatis and HSV-2 were present among 22% and 6% of the women, respectively. There was a significant correlation between the women's complaint of vaginal discharge and previous C trachomatis infection, lack of lactobacilli and presence of leucocytosis in wet smear. CONCLUSIONS: We have in a population-based study of young healthy women found that one out of four women had some kind of lower genital tract complaint. Itching was the most commonly reported symptom and was associated with pseudohyphae and acetowhite patches. Reported vaginal discharge and soreness were associated with the history of a past C trachomatis infection and signs of a disturbed vaginal flora.

Adult↗
PubMed1994

Human papillomavirus type 18 E6* mRNA in primary tumors and pelvic lymph nodes of Hungarian patients with squamous cervical cancer.

Seven biopsy specimens from squamous-cell carcinomas of the uterine cervix were examined by RT-PCR for human-papilloma-virus(HPV)-specific transcripts. With our HPV18-transcription-specific primer pair (5' nts 127-149; 3' nts 587-607), all 7 were shown to contain one strong viral mRNA signal from the early 6/early 7 open reading frames (E6/E7 ORFs). Sequence analysis of the cloned PCR product proved that the transcript was generated by splicing out an intron in E6 from nucleotides 233 to 416, thereby corresponding to the HPV18 E6* spliced mRNA. Nine out of 9 metastatic and 5 of 7 histologically negative lymph nodes from the same patients were also found to be positive for the same mRNA transcript. However, 4 HPV18 unrelated primary tumors and the connected regional pelvic lymph nodes (3 metastatic, 7 histologically negative) were negative for the HPV18 E6* mRNA. Cytokeratin signals indicating tumor cells of epithelial origin were detected in 7 out of the 9 transcript-positive lymph nodes with histological signs of metastasis and in 2 out of the 5 transcript-positive histologically negative lymph nodes. This suggests that the dispersion of the epithelial monoclonal tumor cells was lymphogenic in origin.

Adult↗
PubMed1994

Genome type analysis of Chilean adenovirus strains isolated in a children's hospital between 1988 and 1990.

In a study designed to evaluate the genetic variability of adenovirus strains associated with infantile cases of respiratory disease requiring hospitalization, a collection of 136 adenovirus isolates obtained in the Roberto del Rio Children's Hospital of Santiago, Chile between June 1988 and November 1990 was studied by restriction enzyme analysis. Nasopharyngeal aspirates were obtained on admission from children under 2 years. During the study period a total of 227 adenovirus respiratory infections (ARI) were diagnosed at the ward for ARI by immunofluorescence, representing 23% of all admissions. Fifty percent of the 136 typed strains were found to belong to subgenus B, and the other 50% corresponded to subgenus C. Digestion with a set of seven enzymes allowed the identification of nine different genome types of subgenus C, three of which had not been previously described, exhibiting novel restriction patterns with either BgI II or BstEII. Ad7h, identified in 66 isolates, was the predominant genome type and was associated with the nine cases requiring mechanical respiratory assistance and with the two fatalities recorded during the 29 months. No differences were found between the age and sex distribution of subgenus B and C genomic variants, but the mean length of hospital stay (X +/- 2 SE) recorded among patients infected with subgenus B types was significantly higher (17.72 + 4.52 days (n = 55) vs. 7.54 + 1.70 days (n = 53); F = 17.22; P < 0.0001).

Acute Disease↗