Anti-desmoglein 1 antibodies in healthy related and unrelated subjects and patients with pemphigus foliaceus in endemic and non-endemic areas from Tunisia

Background  Pemphigus foliaceus is an autoimmune blistering skin disease characterized by the production of pathogenic IgG autoantibodies directed against desmoglein 1.
Aim  To determine the prevalence of anti-desmoglein 1 antibodies in healthy subjects and their distribution in the different regions of Tunisia and to better identify endemic areas of pemphigus foliaceus.
Methods  We tested, by enzyme-linked immunoserbent assay, sera of 270 normal subjects recruited from different Tunisian areas and 203 related healthy relatives to 90 Tunisian pemphigus foliaceus patients.
Results  Seventy-six patients (84.4%), 20 healthy controls (7.4%), and 32 relatives (15.76%) had anti-desmoglein 1 antibodies. In southern regions where pemphigus foliaceus is associated with a significant sex ratio imbalance (9 female : 1 male in the south vs. 2.3 : 1 in the north) and a lower mean age of disease onset (33.5 in the south vs. 45 years in the north), a higher prevalence of anti-desmoglein 1 antibodies in healthy controls was observed (9.23% vs. 5.71% in the north). Interestingly, the highest prevalence of anti-desmoglein 1 antibodies in healthy relatives (up to 22%) was observed in the most rural southern localities. More than half anti-desmoglein 1–positive healthy controls were living in rural conditions with farming as occupation, which suggests that this activity may expose the subjects to particular environmental conditions.
Conclusion  These results show that the endemic features of Tunisian pemphigus foliaceus are focused in these southern areas more than in other areas and that both environmental and genetic factors contribute to the disease.

Conflicts of interest

None declared.     

Inaccuracies associated with the automated measurement of mean cell hemoglobin concentration in dehydrated cells

Because of discrepancies between electronically and manually measured values of mean cell hemoglobin concentration (MCHC) encountered in studies of pathologic red cells, we studied the effect of cell water content on MCHC measurements by both methods. A series of red cell samples with varying water contents (54%-164% normal) were prepared from normal cells using the antibiotic nystatin. MCHC was then measured, using the microhematocrit centrifuge and three different electronic cell counters in common laboratory use. For MCHC values above 36 g/dl as measured by the spun hematocrit method, all three electronic counters under estimmated the MCHC, with increasing error as the true MCHC increased. For MCHC values below 30 g/dl, the values from two conductivity based instruments agreed with those from the spun hematocrit method, whereas one instrument based on light scattering overestimated the MCHC. These results indicate that inaccuracies in the measured mean cell volume (MCV) of dehydrated or otherwise undeformable cells may lead to spurious values for MCHC when electronic cell counters are used.     

一体化PET/MR检查临床护理操作规范(2017版)

一体化PET/MR检查护理规范是关于PET/MR检查过程中对于护理人员的工作要求,包括检查前准备、注射药物护理、检查时护理、检查后护理、对比剂不良反应处理和个人辐射防护。旨在为核医学科护士在临床PET/MR检查中提供实用且行之有效的处理操作规范。     

Bone marrow imaging: magnetic resonance studies related to age and sex

Measurements of T1 and T2 relaxation values and spin density of the lumbar vertebral bone marrow were performed in 212 patients, and the results were correlated with the patients' age and sex. T1 and T2 relaxation times for bone marrow in the lumbar vertebral bodies showed a progressive decrease with age for both sexes (except for the T2 relaxation values in female patients). The replacement of hematopoietic marrow by fatty marrow could explain the decrease in T1 and T2. The T1 and T2 values were in the same range for the first two age groups (age 1-10 years and age 21-40 years) and became slightly greater for the older female patients (age 51 years and older) than for the older males. This could be due to the loss of bone and mineral content, which is more rapid and significant for women. These normal T1 and T2 values may provide a baseline for future evaluation of diseases involving the lumbar spine.     

Estimating treatment effects in randomized clinical trials in the presence of non-compliance

In clinical trials where patients are randomized between two treatment arms, not all patients comply with the treatment they were randomly assigned to. The reasons for (non)compliance may be associated with the outcome variable and thereby act as confounders. The standard way of analysing such trials is by the 'intention-to-treat' principle, which allows the use of permutation tests. Conclusions drawn from such tests do not depend on untested assumptions such as absence of confounding. However, this approach may yield biased estimators for the causal effects of treatments. We consider the estimation of such effects for clinical trials where non-compliers can be considered to have switched to the other trial arm. The most important example of this is the placebo-controlled clinical trial where no substantial placebo effects are anticipated. We consider the situation where the relationship between compliance, and thus treatment received, and outcome is influenced by unobserved confounders. The residual of the regression of the actual treatment indicator variable on the randomization arm indicator variable is shown to 'intercept' the effect of such confounders. Inclusion of this residual in a multivariate analysis, in conjunction with the treatment indicator variable, should thus adjust for confounding. Examples are given. In those examples, the results are similar to those obtained by more complex methods.