Generation of self‐renewing immature dendritic cells from mouse spleen that can take up mycobacteria and present antigens to T cells

Pal R, Marwaha S, Pepponi I, Mann JFS, Paul MJ, Reljic R. Generation of self‐renewing immature dendritic cells from mouse spleen that can take up mycobacteria and present antigens to T cells. APMIS 2010; 118: 729–38. Dendritic cells (DC) play a key role in driving the adaptive immune response to Mycobacterium tuberculosis (MTB), the causative pathogen of tuberculosis (TB). However, studying these important yet very sparse immune cells in the context of MTB pathogenesis is severely restricted by the lack of suitable cell lines and the complexity of culturing of DC progenitors, usually obtained from the bone marrow. However, significant advances have been made towards generating long‐term DC cultures from various lymphoid tissues. Here, we report the evidence for generating a long‐term, self‐renewing DC culture from the Balb/c mouse spleen. We demonstrate that these cells, termed IDC‐3, have a myeloid DC origin, i.e. they are CD11c⁺CD11b⁺⁺CD8‐α^?F4/80^+/? and that they also display a phenotype MHC‐II⁺CD16/32⁺⁺CD80^+/?CD86⁺, indicating that they are immature DC. Following incubation with Mycobacterium bovis BCG (Bacillus Calmette Guerin), the IDC‐3 efficiently took up bacteria and acquired the morphology of mature DC. Importantly though, when IDC‐3 were pre‐stimulated with a mycobacterial antigen in vitro, they were able to induce proliferation of T lymphocytes from mice immunized with the same antigen. The T‐cell stimulatory potential of IDC‐3 was further enhanced when the cells were co‐stimulated with an anti‐CD40 mAb. We therefore suggest that the IDC‐3 culture system could be a useful tool for studying the interaction of DC with mycobacteria.     

ULTRASTRUCTURAL STUDY OF HYALURONIC ACID BEFORE AND AFTER THE USE OF A PULSED ELECTROMAGNETIC FIELD, ELECTRORYDESIS, IN THE TREATMENT OF WRINKLES

Background. Treatment of wrinkles has become an increasing problem for dermatologists. Hyaluronic acid is a component of the family of glycosaminoglycans (GAGS, substances known for their property of retaining water), that significantly decreases with aging and in wrinkles. A new technique that uses a specific pulsed electromagnetic field, electrorydesis, has been introduced in the treatment of wrinkles associated with aging. The treatment is based on the reported in vitro effects of specific electromagnetic fields on fibroblast cultures (e.g., an increase in DNA synthesis and in the production of collagen and presumably also of GAGS). Methods. The in vivo effects of the electromagnetic field on aged skin (3 subjects aged 50, 56 and 60 years), with particular focus on the ultrastructural modifications and GAGS amount before and after the treatment, were evaluated by electron microscope. Results. The ultrastructural study (tissue stained with al-cian blue) showed after treatment a significant increase (p < 0.005) of the electron-dense granules (corresponding to hyaluronic acid), located in collagen elastic fibers, and in the soluble matrix. This presumably leads to subsequent edema that was clinically evident after the treatment. Conclusions. These data suggest that the increased levels of GAGS and the subsequent edema of the dermis could explain at least in part the clinical changes observed after electrorydesis treatment (e.g., swelling and “disappearance” of the wrinkle).     

Home mechanical ventilation in children: Retrospective survey of a pediatric population

BACKGROUND: Home care support is beneficial for children needing mechanical ventilation, when clinically stable. METHODS: A retrospective analysis was carried out of the long-term home ventilation management of a pediatric population with chronic respiratory failure composed of 20 ventilator-dependent children categorized according to age, diagnosis and ventilation support. Age groups consisted of 10% under 1 year, 30% between 2 and 5 years, 30% between 6 and 12 years, and 30% older than 12 years. Diagnostic categories included myopathic disorder, n = 5; congenital central hypoventilation syndrome, n = 6; chest wall disorder, n = 5; cystic fibrosis, n = 1; pulmonary hypertension, n = 1; and diaphragmatic paralysis, n = 2. RESULTS: Sixty-five percent were ventilated using non-invasive mode (NIMV): eight with nasal mask, five with full-face mask, and two children in NIMV also used negative pressure mode; 35% were ventilated using tracheostomy, one of them also used a diaphragmatic pacer. Seventy percent needed nocturnal ventilatory support, (20% 12-18 h, 10% full-day). A total of 18 children were included in the home care and follow-up program. Two children died: one because of worsening of his chronic disease and one because of septic shock. CONCLUSION: Although home care ventilation is not yet widely diffused, it represents a valid alternative to long hospitalization for children with stable chronic respiratory failure.     

INTESTINAL MOTILITY DISORDER INDUCED BY FREE RADICALS: A NEW MODEL MIMICKING OXIDATIVE STRESS IN GUT

Literature data suggest that the inflamed intestine may be subjected to a considerable oxidative stress. Therefore, the aim of the present study was to simulate the oxidative stress in the gastrointestinal tract and to explore its effect on intestinal motility. This was attained by treating isolated segments from the rabbit jejunum and from the guinea pig ileum with 2,2'-Azobis (2-amidinopropane) dihydrochloride (ABAP), which generates peroxyl radicals by thermal decomposition. Treatment of intestinal segments with ABAP reduced the muscarinic cholinergic response to acetylcholine in both preparations and induced a dose-dependent inhibition of the spontaneous contractions in the jejunum, also in the presence of tetrodotoxin. ABAP was found to inhibit the contractile response induced by BaCl(2) in guinea pig ileum preparations. This effect was not dose-dependent and it was reversed by Bay-K 8644, which activates voltage operated L-type calcium channels. The rapid and reversible effects of ABAP suggest that it might directly affect L-type calcium channels before lipoperoxidation induction. In conclusion, the results of the present study show that ABAP could be a useful tool to simulate early contractility dysfunctions mediated by oxidative stress.