JK-1, a useful erythroleukemic cell line model to study a controlled erythroid differentiation from progenitors to terminal erythropoiesis.

New hematopoietic cell models have recently emerged through immortalization of CD34 cells to study and understand various molecular mechanisms of erythropoiesis. Here, we characterize the JK-1 CML-derived cell line, previously shown to spontaneously differentiate without cytokines. Using an epigenetic differentiation inhibitor that keeps JK-1 in an early differentiation phase, we characterized 2 progenitor stages: BFU-E JK-1 and CFU-E JK-1 with CD34+/CD36- and CD34-/CD36 + phenotypes respectively.

Duffy antigen is expressed during erythropoiesis in Duffy-negative individuals.

The erythrocyte silent Duffy blood group phenotype in Africans is thought to confer resistance to Plasmodium vivax blood-stage infection. However, recent studies report P. vivax infections across Africa in Fy-negative individuals.

Mice expressing RHAG and RHD human blood group genes.

Anti-RhD prophylaxis of haemolytic disease of the fetus and newborn (HDFN) is highly effective, but as the suppressive mechanism remains uncertain, a mouse model would be of interest. Here we have generated transgenic mice expressing human RhAG and RhD erythrocyte membrane proteins in the presence and, for human RhAG, in the absence, of mouse Rhag. Human RhAG associates with mouse Rh but not mouse Rhag on red blood cells.

AlphaII-spectrin is critical for cell adhesion and cell cycle.

Spectrins are ubiquitous scaffolding components of the membrane skeleton that organize and stabilize microdomains on both the plasma membrane and the intracellular organelles. By way of their numerous interactions with diverse protein families, they are implicated in various cellular functions. Using small interfering RNA strategy in the WM-266 cell line derived from human melanoma, we found that alphaII-spectrin deficiency is associated with a defect in cell proliferation, which is related to a cell cycle arrest at the G1 phase (first gap phase), as evaluated by DNA analysis and Rb phosphorylation.

Phosphorylation and ankyrin-G binding of the C-terminal domain regulate targeting and function of the ammonium transporter RhBG.

RhBG, a human member of the Amt/Mep/Rh/superfamily of ammonium transporters, has been shown to facilitate NH(3) transport and to be anchored to the basolateral plasma membrane of kidney epithelial cells, via ankyrin-G. We showed here that triple alanine substitution of the (419)FLD(421) sequence, which links the cytoplasmic C-terminal domain of RhBG to ankyrin-G, not only disrupted the interaction of RhBG with the spectrin-based skeleton but also delayed its cell surface expression, decreased its plasma membrane stability, and abolished its NH(3) transport function in epithelial cell lines. Similarly, we demonstrated that both anchoring to the membrane skeleton and ammonium transport activity are regulated by the phosphorylation status of the C-terminal tail of RhBG.

A mutant alphaII-spectrin designed to resist calpain and caspase cleavage questions the functional importance of this process in vivo.

alpha- and beta-spectrins are components of molecular scaffolds located under the lipid bilayer and named membrane skeletons. Disruption of these scaffolds through mutations in spectrins demonstrated that they are involved in the membrane localization or the maintenance of proteins associated with them. The ubiquitous alphaII-spectrin chain bears in its central region a unique domain that is sensitive to several proteases such as calpains or caspases.

The ammonium transporter RhBG: requirement of a tyrosine-based signal and ankyrin-G for basolateral targeting and membrane anchorage in polarized kidney epithelial cells.

RhBG is a nonerythroid member of the Rhesus (Rh) protein family, mainly expressed in the kidney and belonging to the Amt/Mep/Rh superfamily of ammonium transporters. The epithelial expression of renal RhBG is restricted to the basolateral membrane of the connecting tubule and collecting duct cells. We report here that sorting and anchoring of RhBG to the basolateral plasma membrane require a cis-tyrosine-based signal and an association with ankyrin-G, respectively.

Large-scale pre-diagnosis study of fetal RHD genotyping by PCR on plasma DNA from RhD-negative pregnant women.

Background: The routine prenatal determination of fetal RhD blood group would be very useful in the management of pregnancies in RhD-negative women, as up to 40% of these pregnancies bear a RhD-negative fetus. The fetal DNA present in maternal plasma offers an opportunity for risk-free prenatal diagnosis.

Aim: This study focused on the feasibility and accuracy of large-scale RhD fetal diagnosis in non-immunized and anti-D immunized RhD-negative women.

[Type B botulism: a family outbreak].

Case Reports: Three cases of an outbreak of familial foodborne botulism are reported. The food incriminated could not be identified despite a careful investigation into the food history of the patients. The outcome was good following endotracheal ventilation and botulism antitoxin trivalent therapy.

[Electrophysiological diagnosis of neurogenic thoracic outlet syndrome].

The neurogenic thoracic outlet syndrome includes the symptoms caused by the compression of the brachial plexus at some point between the interscalene triangle and the inferior border of the axilla. Five patients diagnosed as having neurogenic thoracic outlet syndrome were examined. We determinated clinical and electrophysiological features which lead to thoracic outlet syndrome diagnosis.

The course and prognostic factors of familial amyloid polyneuropathy after liver transplantation.

Familial amyloid polyneuropathy (FAP) associated with mutations of the transthyretin (TTR) gene is the most common type of FAP, a devastating disease causing death within 10 years after the first symptoms. Because most of the amyloidogenic mutated TTR is secreted by the liver, transplantation is widely used to treat these patients, but long-term quantitative evaluation of the effects of liver transplantation on the progression of the neuropathy are not available. We have treated 45 patients with symptomatic TTR-FAP, including 43 with the Met30 TTR gene mutation, and report on the results of periodic evaluation of markers of neuropathy in 25 of them, who have been followed for more than 2 years after liver transplantation (mean follow-up 4 years).

Acute inflammatory demyelinating polyradiculopathy in children: clinical and electrodiagnostic studies.

Clinical and electrophysiological features in 43 children with acute inflammatory demyelinating polyradiculoneuropathy (AIDP) were retrospectively studied. More than one-third of these children were less than 3 years old. Some distinctive clinical features specific to adults or to children were identified.

Bone marrow transplantation in metachromatic leukodystrophy caused by saposin-B deficiency: a case report with a 3-year follow-up period.

A 2-year-old child had a metachromatic leukodystrophy-variant phenotype mainly involving the peripheral nervous system (PNS) that was caused by saposin-B deficiency. Bone marrow transplantation resulted in transient deterioration then continuous improvement of PNS functions. These findings were supported by nerve conduction velocity measurements, but the symptoms ultimately worsened.

[Correlations between clinical deficits, motor and sensory evoked potentials and radiologic aspects of MRI in malformative syringomyelia. 27 Cases].

Twenty-seven patients (15 males, 12 females, age range: 16-66 years) were admitted for malformative syringomyelia diagnosed on MRI with measures of syrinx extending and transverse diameter. Posterior tibial somatosensory evoked potentials (PT SEP), median (M SEP), trigeminal (V3 SEP), brain stem auditory evoked potentials (BEAP), cortical and cervical motor evoked potentials (MEP) were correlated with clinical and radiological findings. SEP abnormalities were not correlated with the duration of symptoms.

Systemic juvenile rheumatoid arthritis and associated Isaacs' syndrome.

We describe a patient with systemic onset juvenile chronic arthritis who developed clinical and electromyographic features of acquired Isaacs' syndrome. This association has not been reported before and possible links between the 2 diseases are discussed.

[Electrophysiologic tests and benzodiazepine hypnosis].

The effects of a pure benzodiazepine antagonist (Flumazenil) on the responses R1 and R2 of the blink reflex, psychomotor tests, and Event Related Potentials (ERP), in six healthy volunteers sedated with Midazolam have been compared. Measurements were made during each of four successive phases. Phase 0 corresponded to control recordings.

Anterior spinal artery syndrome mimicking infantile spinal muscular atrophy.

A baby with acute fetal distress and severe heart malformation presented with persisting hypotonia and muscle weakness. Clinical, electromyography, and muscle biopsy findings were compatible with anterior horn cell disease. Postmortem study showed widespread ischemic necrosis in the anterior gray matter of the spinal cord.

[Negative schizophrenic symptomatology and the P 300 potential].

We studied the latency and amplitude of the P 300 wave of event-related potentials (P 3) in 19 hospitalised schizophrenic patients. We used an odd ball paradigm procedure in acoustic stimulation. We found a negative correlation between the amplitude of P 3 and negative schizophrenic symptomatology, measured by the negative BPRS score and the SANS score.

In vitro model of far-field stationary potentials: boundary effects on propagated potentials.

Far-field stationary potentials have been said to result from several factors such as changes in the anatomical orientation of the direction of a propagating nerve action potential (AP) or local modifications of the impedance in the external volume conductor by changes in its geometry or resistivity. In the case of an impedance variation due to the presence of boundaries in the geometry of the medium, the findings reported in this paper showed that it is possible to record simultaneously AP and stationary potentials which we have called boundary potentials (BPs). The BP amplitude depended on the number of active axons at the boundary, on the distance between the boundary and one of the recording electrodes, and on the local impedance variation.

Conduction block in neuropathies with necrotizing vasculitis.

Thirty-two patients with a mononeuropathy multiplex associated with a systemic necrotizing vasculitis were studied. The main abnormality was a loss of motor and sensory axons confirmed by electrophysiological and histological methods. A conduction block was observed in five patients, but only one was at a usual site of compression.