Low-cost HPV testing and the prevalence of cervical infection in asymptomatic populations in Guatemala

Background

A low cost and accurate method for detecting high-risk (HR) human papillomavirus (HPV) is important to permit HPV testing for cervical cancer prevention. We used a commercially available HPV method (H13, Hybribio) which was documented to function accurately in a reduced volume of cervical specimen to determine the most prevalent HPV types and the distribution of HPV infections in over 1795 cancer-free women in Guatemala undergoing primary screening for cervical cancer by cytology.

Methods

HR-HPV detection was attempted in cervical samples from 1795 cancer-free women receiving Pap smears using the Hybribio™ real-time PCR assay of 13 HR types. The test includes a globin gene internal control. HPV positive samples were sequenced to determine viral type. Age-specific prevalence of HPV was also assessed in the study population.

Results

A total of 13% (226/1717) of women tested HPV+, with 78 samples (4.3%) failing to amplify the internal control. The highest prevalence was found in younger women (< 30 years, 22%) and older ones (≥60 years, 15%). The six most common HR-HPV types among the 148 HPV+ typed were HPV16 (22%), HPV18 (11%), HPV39 (11%), HPV58 (10%), HPV52 (8%), and HPV45 (8%).

Conclusions

In this sample of cancer free women in Guatemala, HPV16 was the most prevalent HR type in Guatemala and the age-specific prevalence curve peaked in younger ages. Women in the 30-59-year age groups had a prevalence of HR-HPV of 8%, however, larger studies to better describe the epidemiology of HPV in Guatemala are needed.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4438-y) contains supplementary material, which is available to authorized users.

Effect of IV contrast on lumbar trabecular attenuation at routine abdominal CT: correlation with DXA and implications for opportunistic osteoporosis screening

Osteoporosis remains under-diagnosed. Routine abdominal CT can provide opportunistic screening, but the effect of IV contrast is largely unknown. The overall performance for predicting osteoporosis was similar between enhanced and unenhanced scans. Therefore, both non-contrast and contrast-enhanced abdominal CT scans can be employed for opportunistic osteoporosis screening.

INTRODUCTION

Osteoporosis is an important yet under-diagnosed public health concern. Lumbar attenuation measurement at routine abdominal CT can provide a simple opportunistic initial screen, but the effect of IV contrast has not been fully evaluated.

METHODS

Mean trabecular CT attenuation values (in Hounsfield units, HU) at the L1 vertebral level were measured by oval region-of-interest (ROI) on both the unenhanced and IV-contrast-enhanced CT series in 157 adults (mean age, 62.0). All patients underwent correlative central DXA within 6 months of CT. Based on DXA BMD of the lumbar spine, femoral neck, and total proximal femur: osteoporosis, osteopenia, and normal BMD was present in 33, 77, and 47, respectively. Statistical analysis included Bland-Altman plots and receiver operating characteristic (ROC) curves.

RESULTS

Mean difference (±SD) in L1 trabecular attenuation between enhanced and unenhanced CT series was +11.2 HU (±19.2) (95 % CI, 8.16-14.22 HU), an 8 % difference. Intra-patient variation was substantial, but no overall trend in the HU difference was seen according to underlying BMD. ROC area under the curve (AUC) for unenhanced and enhanced CT for diagnosing osteoporosis were similar at 0.818 and 0.830, respectively (p = 0.632). Thresholds for maintaining 90 % specificity for osteoporosis were 90 HU for unenhanced and 102 HU for enhanced CT. Thresholds for maintaining 90 % sensitivity for osteoporosis were 139 HU for unenhanced and 144 HU for enhanced CT. Similar diagnostic performance was seen for diagnosing low BMD (osteoporosis or osteopenia) using higher HU cut-offs.

CONCLUSION

Contrast-enhanced CT shows an average increase of 11 HU over the unenhanced series for L1 trabecular attenuation. The overall performance for predicting osteoporosis is similar between the enhanced and unenhanced scans, thus either can be employed for initial opportunistic screening.

The p.Val66Met polymorphism in the BDNF gene protects against early seizures in Rett syndrome

OBJECTIVE

X chromosome inactivation and the MECP2 genotype do not provide the full explanations for the clinical differences between patients with Rett syndrome (RTT), suggesting the involvement of other factors. One MeCP2 target is the brain-derived neurotrophic factor (BDNF) gene. We investigated, according to the MECP2 genotype, the role of the BDNF functional polymorphism (Val66Met) on the severity of RTT.

METHODS

This polymorphism in BDNF was analyzed by PCR and dHPLC in 81 patients with RTT. We studied the association between the MECP2 and BDNF genotypes and the clinical features in each patient.

RESULTS

We found that some RTT features can be correlated with MECP2 genotypes. Missense mutations are associated with a more severe epileptic phenotype (early onset and drug resistance) than other mutations. Non-sense and late truncating mutations lead to a less severe phenotype regarding walking. The distribution of the Val66Met polymorphism was not significantly different between the different groups in regard to the severity of all tested symptoms. However, girls with RTT bearing the Val66Val genotype tend to present earlier seizures than girls with RTT bearing the Met66 allele. No girls with RTT with the Met66 allele presented early seizures.

CONCLUSIONS

Early onset of seizures is linked to the combined MECP2 and BDNF genotypes. The BDNF Met66 allele may protect against seizures, whereas missense mutations in the MBD of MECP2 are more frequently associated with early seizures.