Short-time repeat high-risk HPV testing by self-sampling for screening of cervical cancer

BACKGROUND

Testing for high-risk human papillomavirus (HPV) in primary screening for cervical cancer is considered more sensitive, but less specific, in comparison with Pap-smear cytology. Women with persistent HPV infections have a higher risk of developing cervical intraepithelial neoplasia 2+ (CIN2+) lesions. This study was performed to evaluate the gain in specificity for detection of histologically confirmed CIN2+ lesions achieved by short-time repeat testing for high-risk HPV in women aged 30-65 years, with the primary sample for HPV analysis taken by self-sampling.

METHODS

A total of 8000 women in Uppsala County, aged 30-65 years, who had not attended organised screening for 6 years or longer, were offered self-sampling of vaginal fluid at home and the samples sent for HPV typing. Of these, 8% (669) were not possible to contact or had performed hysterectomy. Women positive for high-risk HPV in the self-sampling test were invited for a follow-up HPV test and a cervical biopsy on average 3 months after the initial HPV test.

RESULTS

In all, 39% (2850/7331) of invited women chose to perform self-sampling of vaginal fluid at home. High-risk HPV infection was found in 6.6% (188) of the women. In all, 89% of the women testing HPV positive performed a follow-up examination, on average 2.7 months, after the first test and 59% of these women were HPV positive in the follow-up test. The prevalence of CIN2+ lesions in women with an initial HPV-positive test was 23% (95% CI 18-30%) and in women with two consecutive HPV-positive tests was 41% (95% CI 31-51%). In women with two positive HPV tests, the prevalence of CIN2+ lesions varied from 49% in women at age 30-39 years to 24% in women at age 50-65 years. Short-time repeat HPV testing increased the specificity for detection of CIN2+ lesions from about 94.2% to 97.8%. The most prevalent HPV types were HPV16 (32%), followed by HPV18/45 (19%) and HPV 33/52/58 (19%).

CONCLUSION

The short-time persistence of high-risk HPV infection in this age group was about 60%. Repeat testing for high-risk HPV using self-sampling of vaginal fluid can be used to increase the specificity in the screening for cervical cancer in women aged 30-65 years.

Regional assignments of NP and MPI on chromosome 7 in pig, Sus scrofa

Fibroblasts from a pig with a spontaneous reciprocal translocation involving chromosome 7, were used to prepare a set of pig-mouse somatic cell hybrids. The isozyme analysis strongly indicated that in pigs, the NP (nucleoside phosphorylase) gene is located on the distal part of the long arm of chromosome 7, (q21----qter), while the MPI (mannose phosphate isomerase) gene is in the region q21----pter. This confirmed previously reported chromosomal assignment of these genes in pigs and that this synteny has been evolutionarily conserved in several different animal species.

Further data on chromosomal assignments of pig enzyme loci LDHA, LDHB, MPI, PEPB and PGM1, using somatic cell hybrids

Clear interspecies differentiation between the chromosomes in pig-mouse somatic cell hybrids was achieved by using the THA-technique for the cytogenetic analysis. The assignments of LDHB and MPI to pig chromosomes nos 5 and 7 respectively, reported previously, were confirmed by analysis of 34 hybrid clones. The LDHA, PEPB and PGM1 genes were assigned to pig chromosomes nos 2, 5 and 6 respectively. Both LDHB and PEPB were indicated to be located on the long arm, except the most proximal part, of pig chromosome no. 5. The proposed synteny between LDHB and PEPB in pigs is in accordance with the synteny observed between these two loci in several other mammalian species.

Temporal trends of HLA genotype frequencies of type 1 diabetes patients in Sweden from 1986 to 2005 suggest altered risk

The aim of this study was to compare the frequency of human leukocyte antigen (HLA) genotypes in 1-18-year-old patients with type 1 diabetes newly diagnosed in 1986-1987 (n = 430), 1996-2000 (n = 342) and in 2003-2005 (n = 171). We tested the hypothesis that the HLA DQ genotype distribution changes over time. Swedish type 1 diabetes patients and controls were typed for HLA using polymerase chain reaction amplification and allele specific probes for DQ A1* and B1* alleles. The most common type 1 diabetes HLA DQA1*-B1*genotype 0501-0201/0301-0302 was 36% (153/430) in 1986-1987 and 37% (127/342) in 1996-2000, but decreased to 19% (33/171) in 2003-2005 (P \ 0.0001). The 0501-0201/0501-0201 genotype increased from 1% in 1986-1987 to 7% in 1996-2000 (P = 0.0047) and to 5% in 2003-2005 (P > 0.05). This study in 1-18-year-old Swedish type 1 diabetes patients supports the notion that there is a temporal change in HLA risk.

Isolation, characterization and chromosomal assignment of a partial cDNA for porcine 6-phosphogluconate dehydrogenase

A partial cDNA for 6-phosphogluconate dehydrogenase (PGD, EC 1.1.1.44) was isolated from a porcine liver cDNA library using a rat PGD cDNA. The identity of the PGD cDNA was confirmed by DNA sequencing and comparison of the amino acid sequence with the corresponding ovine sequence. The PGD cDNA was assigned to 6q2.5-2.7 by in situ hybridization.

Chromosomal localization of the glucose phosphate isomerase (GPI) gene in cattle, sheep and goat by in situ hybridization--chromosomal banding homology versus molecular conservation in Bovidae

A porcine genomic glucose phosphate isomerase (GPI) DNA probe was used for in situ hybridization with metaphase chromosomes in cattle, sheep and goat. The probe gave distinct signals on the q22----proximal part of the q24 segment of chromosome 18, 14 and 18 in cattle, sheep and goat, respectively, indicating the location of GPI gene. The three species belong to the family Bovidae and have high resemblance in chromosome banding patterns. The localization of the GPI locus to the same site on chromosomes with almost similar banding patterns suggests high degree of homology at these sites in the three species. Correlation between banding homologies and possible similarities at the molecular level is discussed.

Sister chromatid exchange in chromosomes of cattle from three different breeds reared under similar conditions

A homogeneous group (same sex, age and environmental conditions) of 35 Italian cattle of the Podolian, Friesian, and Romagna breeds was investigated concerning the spontaneous incidence of sister chromatid exchange (SCE). The mean values of SCEs/cell were 7.9 +/- 3.4, 7.1 +/- 3.3, and 7.3 +/- 3.2 in the Podolian, the Friesian, and the Romagna breeds, respectively, with significant differences between the Podolian and the Friesian breeds. Simultaneous disclosure of SCEs and fluorescent G-bands in the lighter chromatid made possible the identification of chromosome 1, in addition to the biarmed X and Y chromosomes. The inter-chromosomal SCE-distribution revealed a nonrandom pattern due to significantly increased values of SCEs in chromosomes 1 and X, particularly in the Romagna breed.

Stillborns, partially monosomic and partially trisomic, in the offspring of a boar carrying a translocation: rcp(14;15)(q29;q24)

Smaller liters and an increased rate of stillbirth were observed among the offspring of a boar carrying a reciprocal translocation, rcp(14;15)(q29;q24). The translocation appeared to be of de novo origin since, according to the owner, the sire and dam of the proband boar both produced normal-sized litters and no stillbirths. The increased rate of stillbirth among offspring of the proband was due to the production of zygotes partially monosomic for chromosome 14 (14q29-qter) and partially trisomic for chromosome 15 (15q24----qter). Three out of 4 such stillborn piglets had a cleft palate. One of the 4 also had a cardiac septal defect. Two partially monosomic and partially trisomic foetuses recovered at 95 days' pregnancy appeared patho-anatomically normal. The smaller litters were assumed to be due to an early wastage of embryos having other types of unbalanced karyotypes caused by the reciprocal translocation.

Localization of the citrate synthase (CS) gene to the p12-p13 bands of chromosome 5 in pigs by in situ hybridization

Citrate synthase (CS) is a key enzyme of the Krebs tricarboxylic acid cycle. A 1.4 kb porcine CS cDNA probe was used to chromosomally localize the CS gene in pigs by in situ hybridization. Two in situ hybridization experiments were conducted. Although the first experiment indicated a distinct signal on the 5p12-p13 bands, a secondary signal was observed on the 13q24-q32 bands. Hence, a second in situ hybridization experiment was conducted at higher stringency. The results demonstrated a consistent signal on the 5p12-p13 bands, and the signal on chromosome 13 was scattered with no prominent secondary peak. The CS gene was therefore assigned to the p12-p13 bands of chromosome 5 in pigs.

Localization of the glucose phosphate isomerase gene to the p12----q21 segment of chromosome 6 in pig by in situ hybridization

The glucose phosphate isomerase (GPI) locus is closely linked to the halothane sensitivity locus in pig. The chromosomal localization of GPI in pig was confirmed to 6p12----q21 by using in situ hybridization. Of the total grains, 25 percent were located on chromosome 6, with about 65 percent clustered in the cent----q21 segment, suggesting the presence of the GPI gene on the very proximal part of the q arm. The efficiency of hybridization was found to be affected by ultraviolet irradiation of metaphases for RBA-banding before hybridization. The irradiated metaphases had higher background grains than the non-irradiated metaphases.

Assignment of the bovine immunoglobulin gamma heavy chain (IGHG) gene to chromosome 21q24 by in situ hybridization

By the use of in situ hybridization, the bovine immunoglobulin gamma heavy chain (IGHG) gene was assigned to chromosome 21q24. Fifteen percent of the total grains were scored on chromosome 21, with about 65 percent of these grains located on the q24 band. The present results confirm a previous synteny study and provide the precise chromosomal localization of this gene in the cattle genome.

High-resolution studies on late-replicating segments (G + C bands) in mammalian chromosomes

High resolution of late-replicating segments (G + C bands) in chromosomes of human, cattle and water buffalo was obtained by using 5-bromodeoxyuridine incorporation early in the cell cycle, simultaneous with methotrexate treatment combined with reduced colcemid treatment and addition of ethidium bromide, which increased the proportion of prometaphase cells. Giemsa counterstaining, following fluorescence microscopy observation and treatment with 2 x SSC, improved the resolution of the banding patterns, particularly in the pericentromeric regions. Acrocentric bovine and water buffalo chromosomes, which were seen to be C-positive by fluorescence microscopy observation and C-negative after counterstaining, showed the presence of subcentromeric G-positive bands within the heterochromatic blocks of several chromosomes.