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Biomedical subjects

S N Tabrizi

Publications and source records attributed to S N Tabrizi.

At least 55 records · Page 3Linked to original sources
PubMed1994

The detection of HPV DNA, the size of tampon specimens and the menstrual cycle.

OBJECTIVE: To determine if HPV detection or the size of a tampon specimen is affected by the menstrual cycle. MATERIALS: Two hundred and eighty women between 18-35 years of age attending a gynaecology clinic at The Royal Women's Hospital were enrolled. Each woman completed a questionnaire on the risk factors of HPV infection and provided a tampon specimen. Specimens were analysed for the presence of HPV DNA (polymerase chain reaction with the L1 consensus primers) after the pellet volume and number of cells was assessed. RESULTS: The mean age of the 298 women enrolled in this study was 27.0 years (SD 4.5, range 18-35). Ninety two (30.9%) of the tampon specimens were positive for HPV using the L1 consensus primer. The detection of HPV DNA was not associated with the quartiles of the menstrual cycle (p = 0.32). Both the pellet volume and the number of cells from a tampon specimen were greater during the mid cycle, although this was significant for the pellet volume only (p = 0.002 and 0.1 respectively). The pellet volume was not significantly associated with other variables assessed by the questionnaire. The number of cells from a tampon specimen increased with the numbers of life time sexual partners (p = 0.02) and was higher for a single marital status (p = 0.0008). CONCLUSION: The timing of the menstrual cycle effects the size of tampon specimens but not the probability of detecting HPV DNA.

Adolescent↗
PubMed1994

Human papillomavirus infection and its relationship to recent and distant sexual partners.

OBJECTIVE: To determine the relation between the detection of genital human papillomavirus (HPV) DNA and the number of new sexual partners in the last year, 1-5 years, and 5-10 years. METHODS: In a cross-sectional study, 298 women collected tampon specimens and completed self-answer questionnaires on the known risk factors for HPV infection, including the number of sexual partners during the last 1, 5, and 10 years. The tampons were analyzed for the presence of HPV DNA by polymerase chain reaction using L1 consensus primers. RESULTS: Ninety-two (30.9%) tampons were positive for HPV DNA. In univariate analysis, the presence of HPV DNA was associated with a younger age, single marital status, a previously abnormal or currently abnormal Papanicolaou smear, and one or more new sexual partners in the last year, 1-5 years, and 5-10 years. The presence of HPV DNA was not associated with education level, past pregnancy, current or past oral contraceptive use, or the age at first intercourse. In multivariate analysis, only the number of sexual partners during the last year and 1-5 years, and a previously abnormal Papanicolaou smear were associated with HPV. CONCLUSION: The presence of HPV DNA is best predicted by the number of new sexual partners in the last 5 years. Transiently detectable HPV DNA is one possible explanation for this observation.

Adolescent↗
PubMed1994

Simultaneous detection and typing strategy for human papillomaviruses based on PCR and restriction endonuclease mapping.

The aim of this study was to devise a simple and reliable method for simultaneous detection and typing of genital human papillomaviruses (HPVs). The method comprises three steps (i) amplification of sample DNA with the L1 consensus primers, (ii) digestion of PCR products with restriction endonuclease RsaI and (iii) hybridization of digested PCR products with a unique oligonucleotide probe that detects different fragments of the six most common genital HPV genotypes, namely, HPV types 6, 11, 16, 18, 31 and 33. Seventeen clinical specimens were analyzed by this method and compared to Southern blot using full genomic HPV DNA probes and to PCR using type-specific probes. All three tests agreed with at least one HPV type; however, the new method identified more additional HPV types in cases of mixed infections.

Base Sequence↗
PubMed1994

Prevalence of HPV DNA in cervical specimens in women with renal transplants: a comparison with dialysis-dependent patients and patients with renal impairment.

The aim of this study was to assess the prevalence of human papillomavirus (HPV) DNA in women who had received a renal transplant and to compare this with two control groups. Women who had a functioning renal transplant for greater than 6 months (n = 69) were compared with women on maintenance dialysis (n = 89) and women with impaired renal function (creatinine 0.15-0.39 mmol/l) (n = 22). Women were excluded if they had had a hysterectomy, were older than 65 years, or were not yet sexually active. A questionnaire and cervical scrape were obtained from each participant. The cervical scrape was analysed for HPV DNA using PCR and the L1 consensus primers. The participation rate of transplant patients, dialysis patients and those with impaired renal function ('normal' group) was 69, 68, and 78% respectively. The characteristics of the three groups of women at enrollment were similar. No cytological abnormalities were present in the 'normal' population but 11 of 89 patients on maintenance dialysis and nine of 69 transplant patients had cytological abnormalities of atypia or greater (P = 0.08 and P = 0.07, for 'normal' compared to dialysis and transplant groups respectively). One (4.5%) of the 'normal' women had evidence of HPV DNA, while 18 (20%) of patients on maintenance dialysis and 15 (22%) of transplant patients were positive (P = 0.07 and P = 0.05, for 'normal' compared to dialysis and transplant groups respectively). This study suggests that not only transplant recipients but also dialysis patients may have a higher prevalence of risk factors (cytological abnormalities and HPV DNA) for the development of cervical cancer.

Adult↗
PubMed1993

Elimination of extracellular bacteria by antibiotics in quantitative assays of bacterial ingestion and killing by phagocytes.

In vitro assays to quantify the bactericidal capacity of phagocytes require the removal of extracellular bacteria from the reaction mixture before intracellular bacteria are released from the phagocytic cells and counted. This may be achieved by using an antibiotic, such as gentamicin, which has a rapid bactericidal action coupled with limited ability to cross cytoplasmic membranes. In this study, we investigated the susceptibility of Escherichia coli and Yersinia enterocolitica to killing by mouse peritoneal macrophages. Extracellular bacteria in the reaction mixture were eliminated with gentamicin, whereafter the antibiotic was enzymatically inactivated using gentamicin acetyl transferase (GAT). The method has few washing stages, thus reducing the likelihood of inadvertent removal of macrophages or bacteria from the reaction mixture. The assay disclosed clear differences in the ability of E. coli and Y. enterocolitica to survive phagocytosis by macrophages.

Acetyltransferases↗
PubMed1993

Comparison of polymerase chain reaction and culture techniques for detection of Chlamydia trachomatis.

The aim of this study was to compare culture and polymerase chain reaction techniques in detection of Chlamydia trachomatis in clinical specimens. Two hundred clinical specimens previously examined for C. trachomatis by culture were analysed blindly by polymerase chain reaction. A 144 bp fragment of DNA from the MOMP of C. trachomatis was amplified. In addition, a 250 bp segment of beta-globin gene was amplified as an internal control. In 27 culture negative specimens, the beta-globin amplicon was not detected. Of the 173 specimens assessable by PCR, 24 (13.8%) were positive by both methods. Four specimens were positive by PCR and negative by culture. Three were collected post-antibiotic treatment; two were from previous culture-proven chlamydia infection suggestive of the presence of DNA of non-viable organisms, and one case was toxic by culture. No specimen was positive by culture and negative by PCR. Overall PCR when compared to culture had a sensitivity of 100% and specificity of 97.3% with positive and negative predictive values of 85.7% and 100%, respectively. PCR is especially useful when culture results can not be confirmed due to toxicity, inadequate transport or insufficient specimen collected.

Anal Canal↗
PubMed1993

Detection of human papillomavirus DNA and mRNA using synthetic, type-specific oligonucleotide probes.

Type-specific 30'mer-36'mer oligonucleotide probes complementary to mRNA transcribed from the E6 and E7 open reading frames of HPV 6b/11, 16, 18 and 33 were designed using the published nucleotide sequences. As oligonucleotides are easily and relatively cheaply synthesized in large amounts and are free of vector DNA, they were assessed for potential use in routine clinical detection and typing of HPV. Multiple Southern and dot blots of cloned HPV 6b, 11, 16, 18, 31 and 33 DNA, and of DNA extracted from cell lines carrying integrated HPV 16 and 18 genomes were prepared. In addition, Northern and dot blots of RNA extracted from the HPV-containing cell lines HeLa, CaSki and SiHa, were also prepared. All filters were first probed with the oligonucleotide and then with the corresponding full-genomic HPV DNA probe and their relative sensitivities and specificities compared: both probe types were labelled with 32P. The oligonucleotide probes were all as specific as the full-genomic probes for Southern, DNA and RNA dot blot hybridisations. The HPV 16 and 18 oligonucleotide probes detected HPV transcripts of the appropriate sizes in the cell line RNA. For DNA detection, oligonucleotide probes were up to 10 times less sensitive than the full-genomic probes, but for RNA detection, they were more sensitive. The sensitivity for both HPV DNA and RNA detection could be improved by using two type-specific oligonucleotide probes in combination, without reducing the specificity. The ease of preparation and handling of oligonucleotide probes, together with their lack of contaminating vector DNA, suggests that they may have some advantages over full-genomic probes for the clinical detection and typing of HPV.

Base Sequence↗
PubMed1993

Southern blot and dot blot hybridisation compared to PCR for the detection of human papillomavirus DNA in biopsies of the uterine cervix from women with dysplasia.

The aim of this study was to compare the sensitivity of Southern blot (SB) and dot blot (DB) hybridisation with polymerase chain reaction (PCR) for the detection of HPV in cervical biopsies from samples with differing histology. One hundred and forty seven women with cervical dysplasia had biopsies performed; one sample was analyzed for HPV DNA from types 6/11, 16, and 18 by SB, DB and PCR (L1 consensus primer and type specific probes) while an adjacent sample was examined histologically. The histology of the samples was normal in 40 (27%), squamous metaplasia in 25 (17%), inflammation 2 (1%) HPV infection 24 (17%), cervical intraepithelial neoplasia (CIN) grade I in 11 (7%), CIN II in 18 (12%), CIN III in 22 (15%), while 5 (3%) had invasive cancer. The number of biopsies positive for HPV DNA from types 6/11, 16, and 18, using the different hybridisation methods was 56 (38%) by dot blot, 57 (39%) by Southern blot hybridisation and 66 (45%) by PCR. When the L1 consensus primer was used 100 (68%) specimens were positive by PCR. The sensitivity of SB and DB hybridisation, as compared with PCR (type specific probes 6/11, 16, 18) was greater in biopsies with abnormal histology (histological grades of HPV infection and greater, as a group) (sensitivity of SB 83%, DB 74%) than those with normal and metaplastic change (as a group) (sensitivity of SB 44%, DB 35%) (P < 0.005 for SB and DB) (inflammation excluded from analysis). This study demonstrated that the sensitivity of SB and DB hybridisation, relative to PCR is greater in samples with abnormal histology than in samples with normal histology.

Journal Article↗
PubMed1993

The absence of HPV DNA in genital specimens from infants.

OBJECTIVE: To identify the prevalence of HPV DNA using the polymerase chain reaction (PCR) in neonatal foreskin and cervical specimens obtained at necropsy. MATERIALS: Foreskin and cervical specimens were obtained from consecutive neonates who had autopsies performed at The Royal Women's Hospital, Melbourne, from June 1991 to February 1992. Specimens were analysed for HPV DNA using the polymerase chain reaction and the L1 consensus primers and generic probes. RESULTS: Specimens were obtained from 98 neonates, 52 males and 46 female. The mean gestational age of the neonates was 29 weeks (range 20-42). Eighty neonates died in utero, three during labour and 15 following delivery. Ninety four were delivered vaginally whilst four were delivered by caesarean section. Samples were collected a mean of 20 hours (range 2-48) from the time of delivery. In 30 cases there was evidence of autolytic change while in the remaining cases, the histology was well preserved. No evidence of HPV DNA was found in any of the samples using the L1 general primers (95% confidence interval 0-3.6%). Recent cervical cytology was available on 70 of the infant's mothers. Six had cytological evidence of HPV infection while the remainder were normal. CONCLUSIONS: HPV DNA is uncommonly detected (by PCR) in foreskin and cervical specimens obtained from neonates.

Cervix Uteri↗
PubMed1992

Influence of a 70 kilobase virulence plasmid on the ability of Yersinia enterocolitica to survive phagocytosis in vitro.

During the course of infection, Yersinia enterocolitica invades tissues where macrophages and polymorphonuclear leucocytes (PMNs) constitute the first line of defence. As expression of virulence in Y. enterocolitica is governed in part by a c. 70 kilobase virulence plasmid (pYV), we investigated the influence of this plasmid on the interaction between Y. enterocolitica and phagocytes in vitro. The results showed that, irrespective of plasmid-carriage, yersiniae survived phagocytosis by macrophages and PMNs. Plasmidless Y. enterocolitica that had grown intracellularly in macrophages, however, were susceptible to killing by PMNs, whereas plasmid-bearing bacteria were resistant. In vitro cultivation of Y. enterocolitica in a Ca(2+)-deficient medium resembling that found within macrophages, did not influence the susceptibility of plasmid-bearing and plasmidless strains to killing by PMNs. These results indicate that passage through macrophages renders plasmidless strains of Y. enterocolitica susceptible to killing by PMNs. This finding may explain some of the differences in the behaviour of plasmid-bearing and plasmidless strains of Yersinia species in vivo.

Cells, Cultured↗
PubMed1992

Tampons: a novel patient-administered method for the assessment of genital human papillomavirus infection.

Assessment of human papillomavirus (HPV) infection usually requires a speculum examination to collect genital specimens. A technique using tampons as a patient-administered method for the collection of specimens was studied by dot blot hybridization (HPV types 6, 11, 16, 18, 31, and 33) and polymerase chain reaction (PCR). Tampons and cervical scrapes were collected from 48 consecutive women attending a dysplasia clinic. Tampons provided a significantly larger pellet volume (P less than .002) and more DNA (P less than .01) than scrapes. There was a close correlation when samples were analyzed for the presence of HPV DNA. Using dot blot hybridization, 8 cervical scrapes (17%) and 9 tampons (19%) were positive for HPV DNA (90% correlation). By PCR, 35 cervical scrapes (73%) and 33 tampons (69%) were positive for HPV DNA (88% correlation). Thus, tampon specimens are an easy method for assessment of genital HPV infection.

Cervix Uteri↗
PubMed1992

Detection of genital human papillomavirus (HPV) DNA by PCR and other conventional hybridisation techniques in male partners of women with abnormal Papanicolaou smears.

OBJECTIVE: To study the prevalence of human papillomavirus (HPV) infection, using several different hybridisation techniques, in men whose female sexual partners had cervical HPV and/or cervical intraepithelial neoplasia (CIN). METHODS: The male genital area was examined colposcopically and areas suspicious of HPV changes were biopsied. Each biopsy was subjected to histological examination and HPV DNA analysis by conventional DNA analysis such as Southern, reverse and dot blot as well as with polymerase chain reaction (PCR). RESULTS: Colposcopic examination of men showed 133 to be normal whilst 82 (38%) had clinical or subclinical lesions. Of 55 colposcopically directed biopsies from the male lesions taken, detection of HPV DNA by hybridisation with conventional techniques and by PCR showed HPV DNA in 29 (53%) and 47 (85%) of biopsies respectively. Overall HPV types 6/11 were the predominant types. In 18 (33%) biopsies positive by PCR, multiple types were found. CONCLUSION: HPV DNA was present in the majority of biopsy specimens taken, with HPV 6/11 being the predominant type. Among methods for HPV DNA detection, PCR was the most sensitive and useful technique.

DNA Probes, HPV↗
PubMed1991

Reduction of vector contamination in detection of human papillomavirus DNA using full-length genomic DNA probes.

Nucleic acid hybridization techniques are currently the most specific and sensitive procedures available for diagnosing and typing human papillomavirus (HPV) infection. HPV genomic DNA cloned into vector pBR322 or related vectors are commonly used as probes for detection of HPV. When isolating HPV insert DNA however, it is difficult to remove all pBR322 DNA. This can result in false positive readings when clinical specimens harbouring sequences homologous to pBR322 are screened. It was found that up to 200 ng of vector-like sequences in a clinical sample could be blocked by the addition of non-labelled, digested pBR322 sequences to the hybridization reaction.

Animals↗
PubMedDate not supplied

Patient-administered tampon-collected genital cells in the assessment of Chlamydia trachomatis infection using polymerase chain reaction.

BACKGROUND: Diagnosis of genital Chlamydia trachomatis infection in women traditionally requires a speculum examination to collect endocervical cells, followed by cell culture. This method is time consuming, requires stringent transport conditions, and is technically demanding. GOALS: To compare tampons as a patient-administered collection method followed by detection with polymerase chain reaction (PCR) with the traditional endocervical swab culture followed by cell culture detection. STUDY DESIGN: At the emergency department of a hospital for obstetrics and gynecology, 1,000 consecutive women with symptoms suggestive of infection with C. trachomatis were tested for C. trachomatis infection by PCR on both tampon (PCR-T) and swab (PCR-S) specimen and by culture of the swab specimen. RESULTS: Seventeen PCR-T and 16 PCR-S specimens were positive; 16 endocervical specimens were positive by culture, and 14 of the endocervical samples were positive by the three methods. Sixty-one PCR-S samples were inadequate as shown by the lack of amplification of the beta-globin gene segment, indicating poor collection of specimens by endocervical swab for chlamydial testing. CONCLUSIONS: Tampon specimens collected for PCR detection provided an easy and sensitive method of detection of C. trachomatis and overcame the obstacle of endocervical sampling and subsequent stringent transport requirements of culture.

Chlamydia Infections↗
PubMedDate not supplied

Human papillomavirus genotype prevalence in cervical biopsies from women diagnosed with cervical intraepithelial neoplasia or cervical cancer in Melbourne, Australia.

Multicenter international phase III clinical trials using multivalent human papillomavirus (HPV) vaccines for cervical cancer (CC) prevention are underway. As HPV immunity is type specific, defining HPV genotype prevalence in different regions to ascertain whether predominant types differ geographically is considerably important prior to vaccine implementation. This study aimed to define HPV genotypes present in CC and high-grade dysplasia among women in Melbourne, Australia. HPV genotype analysis of a cross section of women in Melbourne with cervical dysplasia/cancer was performed. A total of 493 cervical biopsies from patients being treated for moderate (n= 122) or severe (n= 180) cervical intraepithelial neoplasia (CIN II/III) or CC (n= 191) were tested for HPV genotypes using the PGMY09/11 primer system and line blot assay. HPV detection rates were 63.9%, 72.8%, and 86.9% in CIN II, CIN III, and CC biopsies, respectively. The most prevalent HPV genotypes among CC biopsies were HPV-16 (52.9%), HPV-18 (18.3%), HPV-45 (6.3%), HPV-39 (3.1%), and HPV-73 (2.6%). Multiple HPV infections, comprising two to five types, were identified in 14.4% of biopsies, being significantly fewer (5.2%) among CC biopsies (P < 0.0001). These results indicate that the two most prevalent CC-associated HPV genotypes in Australia parallel those described internationally, with type variations thereafter.

Adult↗
PubMedDate not supplied

Serologic response to human papillomavirus 16 among Australian women with high-grade cervical intraepithelial neoplasia.

This study evaluated the detection of human papillomavirus (HPV) 16 antibody in HPV 16-associated cervical intraepithelial neoplasia (CIN) in Australian women. Seroreactivity to HPV 16 L1 virus-like particles was assessed in patients with CIN 2 (n= 169) and CIN 3 (n= 229) lesions previously tested for the presence of HPV DNA. Seropositivity was significantly commoner in women with HPV 16 DNA-positive lesions (98/184) than in women with no HPV DNA in the lesion (15/47) or with HPV of types other than 16 in the lesion (43/167) (P= 0.0004). In addition, seropositivity was observed in 33% (55/169) of women with CIN 2 and 46% (106/229) of women with CIN 3, in keeping with the lower fraction of CIN 2 (57/169) than CIN 3 (127/229) biopsies positive for HPV 16 DNA. HPV 16 seropositivity is most common in women with HPV 16-associated CIN, but many patients with HPV-associated CIN 3 are seronegative, and HPV 16 seropositivity is common in women with CIN associated with other HPV types. Overall, HPV 16 serology is a poor predictor of presence of HPV 16-associated CIN 3 in patient population studied.

Antibodies, Viral↗