Contribution of flow cytometry to acute leukemia classification in Tunisia

The precision of immunological characterization of leukemias was improved by a certain number of technical innovations, particularly hybridoma production and standardization, resulting in monoclonal antibodies and definition of recognised cellular antigens (designated by CD: Cluster of Differentiation). The aim of this work was to determine the immunophenotyping profile of patients with leukemia, by means of a flow cytometric method: 66 blood samples coming from leukemic persons in the Sahel region were studied by flow cytometry, using about thirty monoclonal antibodies all marked with a fluorochrome, in one or two colour systems to assess their distribution according to type (lymphoid B or T / myeloid) and age, and to search for possible co-expressions of markers of different lineages. The marked preponderance of childhood B-ALL in our series is, at least partly, attributable to the age distribution of the Tunisian population. In agreement with studies from other countries, the majority of AML cases occurred among adults. A high proportion of AML cases in our series co-expressed markers of other lineages. Overall, accurate classification of acute leukemias was possible from a simple peripheral blood sample in 62 of 66 cases (93.9%).     

Comparison of thermoregulatory responses to exercise in dry heat among prepubertal boys, young adults and older males

The purpose of this investigation was to compare the thermoregulatory responses during exercise in a hot climate among three age categories. Eight prepubertal (PP), eight young adult (Y) and eight elderly (O) male subjects cycled at an intensity of 50 +/- 1% of their maximum oxygen uptake (V(O2peak)) for 85 min (three 20 min bouts with three 7 min rest periods) in hot and dry conditions (41 +/- 0.67 degrees C, 21 +/- 1% relative humidity). During the exercise-in-heat protocol, rectal temperature (T(re)) skin temperatures (T(sk)), heart rate (HR), V(O2), V(CO2) V(E), RER, sweat rate, and the number of heat activated sweat glands (HASG) were determined. Despite highest and lowest end-exposure T(re) in the Y and O groups, respectively, the rise in rectal temperature (accounting for differences in baseline T(re)) was similar in all age groups. Changes in body heat storage (DeltaS), both absolute and relative to body mass, were highest in the Y and O groups and lowest in the PP group. While end-session as well as changes in mean skin temperature were similar in all three age groups, HR (absolute and percentage of maximum) was significantly lower for the O compared with the PP and Y groups. Total body as well as per body surface sweating rate was significantly lower for the PP group, while body mass-related net metabolic heat production ((M -- W) kg(-1)) and heat gained from the environment were highest in the PP and lowest in the O group. Since mass-related evaporative cooling (E(sk) kg(-1)) and sweating efficiency (E(sk)/M(sw) kg(-1)) were highest in the PP and lowest in the O group, the mass-dependent heat stored in the body (DeltaS kg(-1)) was lowest in the PP (1.87 +/- 0.03 W kg(-1)) and highest in Y and O groups (2.19 +/- 0.08 and 1.97 +/- 0.11 W kg(-1), respectively). Furthermore, it was calculated that while the O group required only 4.1 +/- 0.5 W of heat energy to raise their body core temperature by 1 degrees C, and the Y group needed 6.9 +/- 0.9 W (1 degrees C)(-1), the PP group required as much as 12.3 +/- 0.7 W to heat up their body core temperature by 1 degrees C. These results suggest that in conditions similar to those imposed during this study, age and age-related characteristics affect the overall rate of heat gain as well as the mechanisms through which this heat is being dissipated. While prepubertal boys seem to be the most efficient thermoregulators, the elderly subjects appear to be the least efficient thermoregulators.     

Coeliac disease – from genetic and immunological studies to clinical applications

Abstract

Coeliac disease is a common and important gastrointestinal disease. It affects at least 1%, most Western European populations and in Nordic countries it is even more frequent. It is strongly associated with certain Human Leukocyte Antigen-DQ genes and triggered by ingestion of wheat gluten and related cereals from rye and barley. The diagnosis relies on a combination of clinical signs, serology and small intestinal biopsy. Work during the last couple of decades has shown that gluten-specific, Human Leukocyte Antigen-DQ-restricted T-cells in the intestinal mucosa are of paramount importance in the disease process. The gluten peptides are chemically modified by the endogenous enzyme transglutaminase 2, the same enzyme that serves as target in today’s sensitive serological tests for coeliac disease. The increasing knowledge on the disease process allows for development of improved diagnosis, patient care and new treatment modalities.     

Tinea capitis outbreak among paediatric refugee population,an evolving healthcare challenge

Outbreaks of tinea capitis (TC) represent a major medical and economic burden. Population migrations have become a phenomenon of increasing relevance for medical conditions management. Given the recent massive arrival of immigrants, we sought to determine epidemiologic trends for TC among paediatric populations at the Tel Aviv Medical Center. We conducted a retrospective study of all TC cases diagnosed between 2010 and 2014 in a paediatric dermatology unit of a tertiary medical centre, serving as a referral centre for the paediatric refugee population from the great Tel Aviv area. Epidemiologic, clinical and treatment data including effectiveness and safety were reviewed. In all, 145 children met the inclusion criteria. Trend analyses showed increases in TC rates over the study period. Incidence rates were higher in boys than in girls. Children of African origin had the highest TC incidence rates as compared with other ethnic groups. Trichophyton violaceum and Microsporum audouinii were the predominant causative organisms. Treatment with griseofulvin was satisfactory in all cases. There was a significant increase in TC incidence rates in the Tel Aviv area over the study period. TV and MA were the predominant organisms. These trends may be a result of poor living conditions and crowded school premises.     

In vivo measurements of lamination patterns in the human cortex

The laminar composition of the cerebral cortex is tightly connected to the development and connectivity of the brain, as well as to function and pathology. Although most of the research on the cortical layers is done with the aid of ex vivo histology, there have been recent attempts to use magnetic resonance imaging (MRI) with potential in vivo applications. However, the high‐resolution MRI technology and protocols required for such studies are neither common nor practical. In this article, we present a clinically feasible method for assessing the laminar properties of the human cortex using standard pulse sequence available on any common MRI scanner. Using a series of low‐resolution inversion recovery (IR) MRI scans allows us to calculate multiple T₁ relaxation time constants for each voxel. Based on the whole‐brain T₁‐distribution, we identify six different gray matter T₁ populations and their variation across the cortex. Based on this, we show age‐related differences in these population and demonstrate that this method is able to capture the difference in laminar composition across varying brain areas. We also provide comparison to ex vivo high‐resolution MRI scans. We show that this method is feasible for the estimation of layer variability across large population cohorts, which can lead to research into the links between the cortical layers and function, behavior and pathologies that was heretofore unexplorable.     

Postexposure-vaccine-prophylaxis against COVID-19

During the COVID-19 pandemic, postexposure-vaccine-prophylaxis is not a practice. Following exposure, only patient isolation is imposed. Moreover, no therapeutic prevention approach is applied. We asked whether evidence exists for reduced mortality rate following postexposure-vaccine-prophylaxis. To estimate the effectiveness of postexposure-vaccine-prophylaxis, we obtained data from the Israeli Ministry of Health registry. The study population consisted of Israeli residents aged 12 years and older, identified for the first time as PCR-positive for SARS-CoV-2, between December 20th, 2020 (the beginning of the vaccination campaign) and October 7th, 2021. We compared “recently injected” patients—that proved PCR-positive on the same day or on 1 of the 5 consecutive days after first vaccination (representing an unintended postexposure-vaccine-prophylaxis)s—to unvaccinated control group. Among Israeli residents identified PCR-positive for SARS-CoV-2, 11 687 were found positive on the day they received their first vaccine injection (BNT162b2) or on 1 of the 5 days thereafter. In patients over 65 years, 143 deaths occurred among 1412 recently injected (10.13%) compared to 255 deaths among the 1412 unvaccinated (18.06%), odd ratio (OR) 0.51 (95% confidence interval [CI]: 0.41–0.64; p < 0.001). A significant reduction in the death toll was observed among the 55–64 age group, with 8 deaths occurring among the 1320 recently injected (0.61%) compared to 24 deaths among the 1320 unvaccinated control (1.82%), OR 0.33 (95% CI: 0.13–0.76; p = 0.007). Postexposure-vaccine-prophylaxis is effective against death in COVID-19 infection.