Root cap size and shape influence responses to the physical strength of the growth medium in Arabidopsis thaliana primary roots.

During the progression of root in soil, root cap cells are the first to encounter obstacles and are known to sense environmental cues, thus making the root cap a potential mechanosensing site. In this study, a two-layered growth medium system was developed in order to study root responses to variations in the physical strength of the medium and the importance of the root cap in the establishment of these responses. Root growth and trajectory of primary roots of Arabidopsis seedlings were investigated using in vivo image analysis. After contact with the harder layer of the medium, the root either penetrated it or underwent rapid curvature, thus enabling reorientation of growth. We initially hypothesized that the root-cap structure would affect apex penetration and reorientation, with pointed caps facilitating and domed caps impeding root penetration. This hypothesis was investigated by analysing the responses of Arabidopsis mutants with altered root caps. The primary root of lines of the fez-2 mutant, which has fewer root-cap cell layers and a more pointed root cap than wild-type roots, showed impaired penetration ability. Conversely, smb-3 roots, which display a rectangular-shaped cap, showed enhanced penetration abilities. These results, which contradict our original hypothesis, reveal a role for resistance to buckling in determining root penetration abilities.

[DRESS complicated by hemophagocytic lymphohistiocytosis in an infant treated for congenital toxoplasmosis]. / DRESS compliqué d'un syndrome d'activation macrophagique chez un nourrisson traité pour une toxoplasmose congénitale.

BACKGROUND: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe disease that may be complicated by hemophagocytic lymphohistiocytosis but this is rarely described in children. PATIENTS AND METHODS: We report the case of a 5-week old infant hospitalized in a pediatric intensive care unit for hemophagocytic lymphohistiocytosis with prolonged fever, splenomegaly, cytopenia, fibrinogen≤1.5g/L, ferritin≥500µg/L, and soluble IL-2 receptor≥2400U/mL. As a result of the presence of a diffuse skin rash, eosinophilia and multiple organ failure that started three weeks after the initiation of a congenital toxoplasmosis treatment, association with DRESS was suggested. DISCUSSION: Exposure to sulfadiazine remains the main factor leading to DRESS in this case. This is probably the trigger event, secondarily complicated by hemophagocytic lymphohistiocytosis, although in our case the diagnosis was made subsequently. The unfortunately poor outcome of this association is probably exacerbated in fragile patients such as young infants. CONCLUSION: Clinicians should be aware of the possibility of DRESS of every early onset associated with hemophagocytic lymphohistiocytosis linked to a treatment started during the neonatal period to avoid any delay in care that might adversely affect the prognosis.

Investigation of primary immune deficiency after severe bacterial infection in children: A population-based study in western France.

BACKGROUND: Infectious diseases are still an important cause of morbidity and mortality in high-income countries and may preferentially affect predisposed children, especially immunocompromised children. We aimed to evaluate the frequency of recommended immunological tests in children with community-onset severe bacterial infection (COSBI) admitted to a pediatric intensive care unit. We also assessed the frequency and described the typology of diagnosed primary immune deficiency (PID). METHODS: We conducted a retrospective observational epidemiological study in six university hospitals in western France. All children from 1 month to 16 years of age admitted to hospital for bacterial meningitis, purpura fulminans, or meningococcal disease between August 2009 and January 2014 were included. We analyzed the frequency, type, and results of the immunological tests performed on children with meningitis, purpura fulminans, or a meningococcemia episode. RESULTS: Among the 143 children included (144 episodes), 84 (59%) and 60 (41%) had bacterial meningitis and purpura fulminans or meningococcemia, respectively: 72 (50%) had immunological tests and 8% had a complete immunological investigation as recommended. Among the 72 children examined for PID, 11 (15%) had at least one anomaly in the immunological test results. Two children had a diagnosis of PID (one with C2 deficit and the other with C8 deficit) and seven other children had possible PID. Thus, the prevalence of a definite or possible diagnosis of PID was 12% among the children examined. CONCLUSION: PID is rarely investigated after COSBI. We raise awareness of the need for immunological investigations after a severe infection requiring PICU admission.

[Metal/alumine metallosis on tibial osteotomy. A case report]. / Métallose par contact métal/alumine sur une ostéotomie tibiale de valgisation. A propos d'un cas.

Metallosis is mainly described in the hip joint at the time of wear or inappropriate use. Cases have also been reported in patients with a knee prosthesis, but never after tibial osteotomy. We report a rare case of metallosis resulting from metal-alumina contact after open wedge tibial osteotomy. The patient complained of pain, which was relieved after removal of the plate nine months after the first operation. Intraoperative inspection revealed metallosis at the synthesis site and local plate wear at zone of contact with the ceramic filler. Removal of the plate and cleaning of the metallosis zone led to full relief of the pain at one and a half months.

Renal artery embolization in a child with delayed hemodynamic instability from penetrating knife wound.

Penetrating laceration injury in the pediatric population may present as an acute or delayed life-threatening injury. Although emergent intra-arterial embolization is commonly utilized in adults, few cases have been reported for children. Surgical treatment for severe renal laceration injuries may require complete nephrectomy; an unfortunate outcome for a pediatric patient if a renal-preserving alternative is feasible. We present a case of penetrating renal laceration in a 10-year-old boy treated with intra-arterial embolization of the lacerated dominant renal artery and subsequent renal perfusion by an uninjured accessory renal artery allowing for renal preservation.

[Influence of body mass index on outcome of total hip arthroplasty via a minimally invasive anterior approach]. / Influence de l'indice de masse corporelle sur la réalisation d'une prothèse totale de hanche par voie d'abord antérieure réduite.

PURPOSE OF THE STUDY: The purpose of this prospective study was to evaluate the influence of the BMI on the feasibility of minimally invasive total hip arthroplasty (THA). MATERIAL AND METHODS: This prospective study included 86 patients (88 THA) operated on via a single minimally invasive incision (7 cm) using an anterior approach on Judet's orthopedic table. Mean age was 63.7 years and mean BMI was 58.8. Forty-one patients were classified in group I (BMI<25) and 46 in group II (BMI >=25). Perioperative data, pain, postoperative blood loss, duration of the procedure, and length of the incision were noted. All patients were reviewed at three months and radiographic analysis was performed to asses the position of the socket and the quality of the cementation. RESULTS: BMI did not appear to be a strict contraindication for a minimally invasive procedure. Nevertheless, bleeding and operative duration were statistically correlated with BMI (epsilon=4.28 and epsilon=2.66). Extension of the wound noted at the end of the procedure in patients with BMI > =25 (t=5.01) may have resulted from greater pressure on the skin and soft tissue due to stronger traction and more abrasion of the skin edges by reamers and rasps. Such damage may lead to more wound complications even though in our experience there was no statistical difference. On the other hand, socket position and cementation did not appear to be correlated with BMI. DISCUSSION: Results concerning duration of procedure, bleeding, hospital stay and rate of complications are contradictory in the literature. At the same time, criteria for patient selection remain unclear. It thus appeared to be of interest to determine whether BMI was a good criterion to determine the feasibility of THA via a minimally invasive procedure. CONCLUSION: BMI appears to be a good criterion to evaluate the risk of wound complications after minimally invasive surgery. On the other hand, other criteria must be found since BMI does not evaluate muscle mass which seems to be of major concern in minimally invasive procedures.

[DRESS syndrome and agranulocytosis, a rare combination]. / Syndrome d'hypersensibilité médicamenteuse et agranulocytose, une association rare.

INTRODUCTION: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe toxidermia that can lead to death from multivisceral failure. We report a case of DRESS associated with febrile agranulocytosis in a child. OBSERVATION: An 8-year-old child was hospitalized for diffuse maculopapular exanthema with edema of the extremities and face associated with cheilitis and febrile agranulocytosis. This symptomatology began 1month after the introduction of carbamazepine for partial epilepsy. The clinical picture was a multisystemic disease with colitis, interstitial pneumonitis, hepatic cytolysis, and hepatocellular insufficiency. HHV7 viral reactivation and increased eosinophils (20%) in the myelogram were demonstrated, providing the diagnosis of DRESS. The progression was favorable after carbamazepine therapy was stopped and systemic corticosteroids were administered. DISCUSSION: DRESS syndrome is a disorder that is unfamiliar to pediatricians. Its association with agranulocytosis is rare and the absence of hypereosinophilia contributed to diagnostic difficulties in this case. The multisystemic failure, the reactivation of HHV7, the increase of eosinophils in the myelogram, and the favorable progression under systemic corticosteroid therapy contributed greatly to the diagnosis. A cutaneous biopsy was not considered necessary for the diagnosis in the case reported herein. CONCLUSION: DRESS syndrome is rarely associated with agranulocytosis, but its diagnosis must be quickly raised so that the incriminated drug can be interrupted.