Repeatability of parametric methods for [18F]florbetapir imaging in Alzheimer’s disease and healthy controls: A test–retest study

Accumulation of amyloid beta (Aβ) is one of the pathological hallmarks of Alzheimer’s disease (AD), which can be visualized using [¹⁸F]florbetapir positron emission tomography (PET). The aim of this study was to evaluate various parametric methods and to assess their test-retest (TRT) reliability. Two 90 min dynamic [¹⁸F]florbetapir PET scans, including arterial sampling, were acquired (n = 8 AD patient, n = 8 controls). The following parametric methods were used; (reference:cerebellum); Logan and spectral analysis (SA), receptor parametric mapping (RPM), simplified reference tissue model2 (SRTM2), reference Logan (rLogan) and standardized uptake value ratios (SUV_r(50–70)). BP_ND+1, DVR, V_T and SUVr were compared with corresponding estimates (V_T or DVR) from the plasma input reversible two tissue compartmental (2T4k_V_B) model with corresponding TRT values for 90-scan duration. RPM (r² = 0.92; slope = 0.91), Logan (r² = 0.95; slope = 0.84) and rLogan (r² = 0.94; slope = 0.88), and SRTM2 (r² = 0.91; slope = 0.83), SA (r² = 0.91; slope = 0.88), SUVr (r² = 0.84; slope = 1.16) correlated well with their 2T4k_V_B counterparts. RPM (controls: 1%, AD: 3%), rLogan (controls: 1%, AD: 3%) and SUV_r(50–70) (controls: 3%, AD: 8%) showed an excellent TRT reliability. In conclusion, most parametric methods showed excellent performance for [¹⁸F]florbetapir, but RPM and rLogan seem the methods of choice, combining the highest accuracy and best TRT reliability.     

Molecular Characteristics,Clinical and Immunologic Manifestations of 11 Children with Omenn Syndrome in East Slavs (Russia,Belarus, Ukraine)

Background

Omenn syndrome [Mendelian Inheritance (OMIM 603554)] is a genetic disease of the immune system, characterized by the presence of fatal generalized severe erythroderma, lymphoadenopathy, eosinophilia and profound immunodeficiency.

Objective

We studied clinical and immunologic presentation of the disease manifestation among East Slavs population with genetically confirmed Omenn syndrome.

Results

We collected clinical and immunologic data of 11 patients (1 from Belarus, 5 – Ukraine, 5 – Russia): 6 females, 5 males. The age of Omenn syndrome manifestation varied from the 1st day of life to 1 year and 1 month, the age of diagnosis – 20 days to 1 year and 10 months. Nine out of 11 patients had classic immunologic phenotype T(+/?)B-NK+, 1 pt had TlowB + NK+ with CD3 + TCRgd + expansion and 1 had TlowB+/?NK+ phenotype. Eight out of 11 pts had mutation in RAG1 gene, 4 out of 8 had c.368-369delAA (p.K86fsX118) in homozygous state or heterozygous compound. In our cohort of patients, we also described two new mutations in RAG genes (p.E722Q in RAG1 and p.M459R in RAG2). At present, 7/11 were transplanted and 5 out of the transplanted are alive.

Conclusion

This study demonstrates that the most popular genetic abnormality in East Slavs children with Omenn syndrome is c.368-369delAA (p.K86fs118) in RAG1 gene, which may be connected with more favorable prognosis because 4/4 patients survived after hematopoietic stem cells transplantation.

     

The spread of hepatitis B and C viruses and the structure of HBsAg subtypes in Kabardino-Balkaria

A seroepidemiological study of the spread of hepatitis B and C viruses (HBV and HCV) was conducted among some population groups in Kabardino-Balkaria. The structure of HBsAg subtypes was also studied in the residents of the republic. The presence of viral hepatitis B markers among the test groups of the healthy population corresponds to the parameters of moderate activity of an epidemic process. The analysis of the immunological structure of the population leads the author to assign Kabardino-Balkaria to highly HBC endemic areas. The occupational factor is demonstrated to be actively involved in the spread of HBC and it is practically of no significance for HCV. An examination could reveal the HBsAg subtype adrq+ that is uncharacteristic of this area.