Analytical sensitivity of four HIV combined antigen/antibody assays using the p24 WHO standard

BackgroundThe Common Technical Specifications for HIV-1 p24 assays published in 2009 fixed the lower limit of detection for obtaining C.E. approval at 2 IU/ml against the WHO standard (first international reference, code NIBSC 90/636); it was previously 50 pg/ml. Some recent fourth generation HIV assays that simultaneously detect antigen and antibody are equivalent to p24 assays, but they were mainly evaluated using p24 antigen standards in pg/ml and little is known of their performance with the IU/ml standard.ObjectivesTo evaluate four of the combined serological assays most commonly used for HIV diagnosis in France against the WHO standard in IU/ml.Study designThe analytical sensitivity of four combined p24 antigen and antibody assays (ARCHITECT HIV Ag/Ab Combo, AxSYM HIV Ag/Ab Combo, VIDAS HIV DUO Quick and VIDAS HIV DUO Ultra) and of one p24 assay (VIDAS HIV p24 II) were determined using dilutions of the WHO standard.ResultsFour of the five assays had a lower limit of detection below 2 IU/ml: 1.24 for ARCHITECT Combo, 0.66 for VIDAS DUO Ultra, 0.43 for VIDAS DUO Quick and 0.73 to 1.15 for VIDAS p24, while that of AxSYM was close to 2 (1.94–2.25).ConclusionsWe have provided the first data on the lower limit of detection of HIV combined assays using the IU/ml WHO standard and demonstrated the need for a single international standard for comparing assays. We recommend the use of this approach in medical laboratory to validate on site their methods.     

Histological and transcriptional study of angiogenesis and lymphangiogenesis in uninvolved skin,acute pinpoint lesions and established psoriasis plaques: An approach of vascular development chronology in psoriasis

BackgroundDysregulation of angiogenesis and lymphangiogenesis could participate in psoriasis pathogenesis. Analysis of nascent psoriasis lesions should help at identifying early vascular anomalies.ObjectiveTo analyse vascular development, angiogenesis and lymphangiogenesis markers expression in uninvolved skin in psoriatic patients (N), early psoriasis lesions or pinpoints (PP) and psoriasis plaques (PSO).MethodsSkin biopsies were taken in 17 patients in N and in PSO and/or PP. The mRNA steady-state level of angiogenesis and lymphangiogenesis markers was measured by RT-PCR. Immunohistochemistry was performed for von Willebrand factor, podoplanin, Ki-67 and VEGFR3. Blood (BV) and lymphatic (LV) vessels expansion was measured by computer-assisted morphometry.ResultsClinical and epidermal aspects indicated that PP are intermediate between N and PSO. While total BV area was already increased in PP similarly to PSO as compared to N, LV area in PP was intermediate between N and PSO. Mean LV size was identical in N and PP and increased in PSO, mean BV size in PP being intermediate between N and PSO. VEGF-A 189 variant was increased in PP as compared to N and PSO. As compared to N, angiogenesis markers (VEGF-A isoforms, PlGF, VEGFR2, NRP-1), VEGF-C and NRP-2 were similarly increased in PP and PSO. Keratin 16 and the lymphangiogenesis markers (VEGFR3, prox-1) were intermediate in PP.ConclusionThese data suggest that the expansion of lymphatic vessels occurs after blood vascular development in psoriasis. Expansion of BV in PP could be followed by vessel enlargement during progression to PSO, in parallel with a decreased VEGF-A 189/VEGF-A 121 balance in plaques.     

Genomic aberrations of the CACNA2D1 gene in three patients with epilepsy and intellectual disability

Voltage-gated calcium channels have an important role in neurotransmission. Aberrations affecting genes encoding the alpha subunit of these channels have been associated with epilepsy and neuropsychiatric disorders such as autism or schizophrenia. Here we report three patients with a genomic aberration affecting the CACNA2D1 gene encoding the α₂δ subunit of these voltage-gated calcium channels. All three patients present with epilepsy and intellectual disability pinpointing the CACNA2D1 gene as an interesting candidate gene for these clinical features. Besides these characteristics, patient 2 also presents with obesity with hyperinsulinism, which is very likely to be caused by deletion of the CD36 gene.     

Theoretical study of the flow rate toward the right heart territory in case of total occlusion of the right coronary artery

In this work, patients with severe coronary disease and chronic occlusion of the right coronary artery (RCA) are studied. In this clinical situation, the collateral circulation is an important factor in the preservation of the myocardium until reperfusion of the area at risk. An accurate estimation of collateral flow is crucial in surgical bypass planning as it can influence the outcome of a given treatment for a given patient. The evaluation of collateral flow is frequently achieved using an index (CFI, Collateral Flow Index) based on pressure measurements.Using a model of the coronary circulation based on hydraulic/electric analogy, we demonstrate, through theoretical simulations, that a wide range of fractional collateral flow values can be obtained for any given distal pressure difference depending on the values of the capillary and collateral resistances.