Glial response to 17β-estradiol in neonatal rats with excitotoxic brain injury.

White-matter injury is the most common cause of the adverse neurodevelopmental outcomes observed in preterm infants. Only few options exist to prevent perinatal brain injury associated to preterm delivery. 17β-estradiol (E2) is the predominant estrogen in circulation and has been shown to be neuroprotective in vitro and in vivo.

Inhaled NO prevents hyperoxia-induced white matter damage in neonatal rats.

White matter damage (WMD) and bronchopulmonary dysplasia (BPD) are the two main complications occurring in very preterm infants. Inhaled nitric oxide (iNO) has been proposed to promote alveolarization in the developing lung, and we have reported that iNO promotes myelination and induces neuroprotection in neonatal rats with excitotoxic brain damage. Our hypothesis is that, in addition to its pulmonary effects, iNO may be neuroprotective in rat pups exposed to hyperoxia.

Use of human umbilical cord blood mononuclear cells to prevent perinatal brain injury: a preclinical study.

Cerebral palsy (CP) is the most frequent neurological disorder associated with perinatal injury of the developing brain. Major brain lesions associated with CP are white matter damage (WMD) in preterm infants and cortico-subcortical lesions in term newborns. Cell therapy is considered promising for the repair of brain damage.

Transplantation of umbilical cord-derived mesenchymal stem cells as a novel strategy to protect the central nervous system: technical aspects, preclinical studies, and clinical perspectives.

The prevention of perinatal neurological disabilities remains a major challenge for public health, and no neuroprotective treatment to date has proven clinically useful in reducing the lesions leading to these disabilities. Efforts are, therefore, urgently needed to test other neuroprotective strategies including cell therapies. Although stem cells have raised great hopes as an inexhaustible source of therapeutic products that could be used for neuroprotection and neuroregeneration in disorders affecting the brain and spinal cord, certain sources of stem cells are associated with potential ethical issues.

Stem cell therapy for neonatal brain injury: perspectives and challenges.

Cerebral palsy is a major health problem caused by brain damage during pregnancy, delivery, or the immediate postnatal period. Perinatal stroke, intraventricular hemorrhage, and asphyxia are the most common causes of neonatal brain damage. Periventricular white matter damage (periventricular leukomalacia) is the predominant form in premature infants and the most common antecedent of cerebral palsy.

Implanted neurosphere-derived precursors promote recovery after neonatal excitotoxic brain injury.

Brain damage through excitotoxic mechanisms is a major cause of cerebral palsy in infants. This phenomenon usually occurs during the fetal period in human, and often leads to lifelong neurological morbidity with cognitive and sensorimotor impairment. However, there is currently no effective therapy.

Nitric oxide plays a key role in myelination in the developing brain.

Inhaled nitric oxide (iNO) is one of the most promising therapies used in neonates, but there is little information available about its effect on the developing brain. We explored the effects of both iNO and endogenous NO on developing white matter in rodents. Rat or mouse pups and their mothers were placed in a chamber containing 5 to 20 ppm of NO for 7 days after birth.

Dynamic conformational changes in the FERM domain of FAK are involved in focal-adhesion behavior during cell spreading and motility.

Focal adhesion kinase (FAK) controls cellular adhesion and motility processes by its tight link to integrin- and extracellular-matrix-mediated signaling. To explore the dynamics of the regulation of FAK, we constructed a FRET-based probe that visualizes conformational rearrangements of the FERM domain of FAK in living cells. The sensor reports on an integrin-mediated conformational change in FAK following cellular adhesion.

Reversal of cell polarity and actin-myosin cytoskeleton reorganization under mechanical and chemical stimulation.

To study reorganization of the actin system in cells that invert their polarity, we stimulated Dictyostelium cells by mechanical forces from alternating directions. The cells oriented in a fluid flow by establishing a protruding front directed against the flow and a retracting tail. Labels for polymerized actin and filamentous myosin-II marked front and tail.

Time-resolved responses to chemoattractant, characteristic of the front and tail of Dictyostelium cells.

In a gradient of chemoattractant, Dictyostelium cells are orientated with their front directed toward the source and their tail pointing into the opposite direction. The front region is specified by the polymerization of actin and the tail by the recruitment of filamentous myosin-II. We have dissected these front and tail responses by exposing cells to an upshift of cyclic AMP.

Phg2, a kinase involved in adhesion and focal site modeling in Dictyostelium.

The amoeba Dictyostelium is a simple genetic system for analyzing substrate adhesion, motility and phagocytosis. A new adhesion-defective mutant named phg2 was isolated in this system, and PHG2 encodes a novel serine/threonine kinase with a ras-binding domain. We compared the phenotype of phg2 null cells to other previously isolated adhesion mutants to evaluate the specific role of each gene product.

Giant lipid vesicles filled with a gel: shape instability induced by osmotic shrinkage.

We report the properties of giant lipid vesicles enclosing an agarose gel. In this system, the lipid bilayer retains some basic properties of biological membranes and the internal fluid exhibits viscoelastic properties, thus permitting us to address the question of the deformation of a cell membrane in relation to the mechanical properties of its cytoskeleton. The agarose gel (concentration c0gel = 0.

[Myocardial beta-adrenergic receptors and left ventricular hypertrophy induced by pressure overload in man].

In experimental models, the characteristics of beta-adrenoceptors in left ventricular hypertrophy (LVH) due to pressure overload remain controversial and no data are still available in man. We investigated right auricular (RA) and left ventricular (LV) beta-adrenoceptors characteristics (125 I cyanopindolol binding) in two groups of patients undergoing valve replacement without heart failure (LV ejection fraction > 55%). Height patients with mitral stenosis (mean age: 64 +/- 4 years) and without LVH (LV mass index < 120 g/m2) constituted the control group and 13 patients with aortic stenosis (mean age: 66 +/- 4 years) and LVH (LV mass index > 150 g/m2) the study group.

[Implantable insulin pump: surgical implantation under local anesthesia. (Technical note apropos of 35 cases)].

The authors report 35 cases of implantation of a programmable implantable insulin pump, under local anesthesia. This technique allows creation of an subcutaneous pocket and introduction of an intraperitoneal catheter for insulin delivery. The morbidity is mainly due to the catheter which becomes thrombosed by a fibrotic pannus at its tip.

Early postoperative sternal approximation after ITA harvesting: computed tomographic evaluation.

Between November 1989 and February 1990, 66 randomized sternotomized patients underwent aortocoronary bypass and were subjected to a sternal scanner in the early postoperative period. Each examination included a manubrial and a sternal body print. At each level, we studied the occurrence of spacing or misalignment of the sternal layers.

A new device: the quick cannulation system.

We describe a new technique for the placing and fixing of extracorporeal circulation cannulae in the heart. Two devices are involved, the first for an atrial or venous return cannula and the second for an aortic perfusion cannula. These allow quick easy cannulation which is very important in emergency surgery.

Abdominal aortic aneurysmectomy in octogenarian patients.

The authors report 56 patients. 80 years of age or older who had an abdominal aortic aneurysm (AAA): twenty seven were operated upon as emergencies, 7 with intra-peritoneal (Group I) and 20 with retro-peritoneal rupture (Group II). Twenty nine underwent elective surgery (Group III).

New helper instrument in cardiac surgery.

A new instrument has been designed for cardiac surgery. It frees the hands of the surgical assistant and is effective either for valve replacement or coronary graft anastomosis. The use of this instrument makes the operation quicker and easier.