The adhesion-GPCR BAI3, a gene linked to psychiatric disorders, regulates dendrite morphogenesis in neurons.

Adhesion-G protein-coupled receptors (GPCRs) are a poorly studied subgroup of the GPCRs, which have diverse biological roles and are major targets for therapeutic intervention. Among them, the Brain Angiogenesis Inhibitor (BAI) family has been linked to several psychiatric disorders, but despite their very high neuronal expression, the function of these receptors in the central nervous system has barely been analyzed. Our results, obtained using expression knockdown and overexpression experiments, reveal that the BAI3 receptor controls dendritic arborization growth and branching in cultured neurons. This role is confirmed in Purkinje cells in vivo using specific expression of a deficient BAI3 protein in transgenic mice, as well as lentivirus driven knockdown of BAI3 expression. Regulation of dendrite morphogenesis by BAI3 involves activation of the RhoGTPase Rac1 and the binding to a functional ELMO1, a critical Rac1 regulator. Thus, activation of the BAI3 signaling pathway could lead to direct reorganization of the actin cytoskeleton through RhoGTPase signaling in neurons. Given the direct link between RhoGTPase/actin signaling pathways, neuronal morphogenesis and psychiatric disorders, our mechanistic data show the importance of further studying the role of the BAI adhesion-GPCRs to understand the pathophysiology of such brain diseases.

Imaging of diffuse metastatic and dystrophic pulmonary calcification in children after haematopoietic stem cell transplantation.

The authors describe three cases of diffuse pulmonary calcification; two metastatic in children with acute transitory renal failure and the other dystrophic in a child with leukaemia. All three patients underwent haematopoietic stem cell transplantation (HSCT). Chest radiographs disclosed diffuse calcification within the lungs. The distribution of this calcification was bilateral but asymmetric. Diagnosis was made in two cases by high resolution computed tomography (HRCT) and in one case by HRCT and bone scan. Radiological characteristics, scintigraphic features, pathological mechanism and clinical outcome of such pulmonary calcification are discussed.

Motor coordination in mice with hotfoot, Lurcher, and double mutations of the Grid2 gene encoding the delta-2 excitatory amino acid receptor.

Grid2(ho/ho) is a loss of function gene mutation resulting in abnormal dendritic arborizations of Purkinje cells. These mutants were compared in a series of motor coordination tests requiring balance and equilibrium to nonataxic controls (Grid2(ho/+)) and to a double mutant (Grid2(ho/Lc)) with an inserted Lc mutation. The performance of Grid2(ho/ho) mutant mice was poorer than that of controls on stationary beam, coat hanger, unsteady platform, and rotorod tests. Grid2(ho/Lc) did not differ from Grid2(Lc/+) mice. However, the insertion of the Lc mutation in Grid2(ho/Lc) potentiated the deficits found in Grid2(ho/ho) in stationary beam, unsteady platform, and rotorod tests. These results indicate a deleterious effect of the Lc mutation on Grid2-deficient mice.

Resistant herpes simplex virus type 1 infection: an emerging concern after allogeneic stem cell transplantation.

Fourteen cases of severe acyclovir-resistant herpes simplex virus type 1 (HSV-1) infection, 7 of which showed resistance to foscarnet, were diagnosed among 196 allogeneic stem cell transplant recipients within a 29-month period. Recipients of unrelated stem cell transplants were at higher risk. All patients received foscarnet; 8 subsequently received cidofovir. Strains were initially foscarnet-resistant in 3 patients and secondarily so in 4 patients. In vitro resistance to acyclovir or foscarnet was associated with clinical failure of these drugs; however, in vitro susceptibility to foscarnet was associated with complete response in only 5 of 7 patients. No strain from any of the 7 patients was resistant in vitro to cidofovir; however, only 3 of 7 patients achieved complete response. Therefore, acyclovir- and/or foscarnet-resistant HSV-1 infections after allogeneic stem cell transplantation have become a concern; current strategies need to be reassessed and new strategies must be evaluated in this setting.

Bax inactivation in lurcher mutants rescues cerebellar granule cells but not purkinje cells or inferior olivary neurons.

Lurcher is a gain-of-function mutation in the delta2 glutamate receptor gene (Grid2) that turns the receptor into a leaky ion channel. The expression of the Lurcher gene in heterozygous (Grid2(Lc/+)) mutants induces the death of almost all Purkinje cells starting from the second postnatal week. Ninety percent of the granule cells and 60-75% of the inferior olivary neurons die because of the loss of their target neurons, the Purkinje cells. The apoptotic nature of the neurodegeneration has been demonstrated previously by the presence of activated caspase-3 and DNA fragmentation. Bax, a pro-apoptotic gene of the Bcl-2 family, has been shown to be involved in developmental neuronal death. To study the role of Bax in Grid2(Lc/+) neurodegeneration, double mutants with Grid2(Lc/)+ mice and Bax knock-out mice (Bax-/-) were generated. Bax deletion had no effect on the death of Purkinje cells and inferior olivary neurons, although a temporary rescue of some Purkinje cells could be detected in P15 Grid2(Lc/)+;Bax-/- animals. From postnatal day 15 (P15) to P60, the number of granule cells in Grid2(Lc/)+;Bax-/-mice did not significantly change and was significantly increased compared with the number found in Grid2(Lc/)+;Bax+/+ mice. Granule cell number in P60 Grid2(Lc/)+;Bax-/- mice corresponded to 70% of the number found in wild-type mice. Our results show that Bax inactivation in Grid2(Lc/+) mice does not rescue intrinsic Purkinje cell death or the target-related cell death of olivary neurons, but Bax inactivation does inhibit persistently target-related cell death in cerebellar granule cells.

Target-related and intrinsic neuronal death in Lurcher mutant mice are both mediated by caspase-3 activation.

The Lurcher (Lc) mutation in the delta2 glutamate receptor gene leads to the presence of a constitutive inward current in the cerebellar Purkinje cells of Lurcher heterozygous mice and to the postnatal degeneration of these neurons. In addition, cerebellar granule cells and olivary neurons of Lc/+ mice die as an indirect effect of the mutation after the loss of their target Purkinje cells. The apoptotic nature of Lc/+ Purkinje cell death remains controversial. To address this question, we studied the involvement of caspase-3, a key effector of apoptosis, in the neurodegenerative processes occurring in Lc/+ cerebellum. Several antibodies recognizing different regions of caspase-3 were used in immunoblotting and immunohistochemical experiments. We demonstrate that pro-caspase-3 is specifically upregulated in the dying Lc/+ Purkinje cells, but not in granule cells and olivary neurons, suggesting that different death-inducing signals trigger variant apoptotic pathways in the CNS. The subcellular localization of pro-caspase-3 was shown to be cytoplasmic and mitochondrial. Active caspase-3 as well as DNA fragmentation was found in numerous granule cells and some Purkinje cells of the Lc/+ cerebellum. Thus, caspase-3 activation is involved in both the direct and indirect neuronal death induced by the Lurcher mutation, strongly supporting the idea that the Lc/+ Purkinje cell dies by apoptosis.

Bax and p53 are differentially involved in the regulation of caspase-3 expression and activation during neurodegeneration in Lurcher mice.

Intrinsic Purkinje cell death in heterozygous Lurcher (Grid2Lc/+) mice is accompanied by the target-related death of granule cells and olivary neurons. The expression of pro-caspase-3 is increased in Grid2Lc/+ Purkinje cells and activated caspase-3 is detected in all three cell types before their death. Bax inactivation in Grid2Lc/+ mutants rescues granule cells but not Purkinje cells. Here, we show that, while Bax inactivation inhibits caspase-3 activation in both cell types, p53 inactivation does not affect caspase-3 activation and neuronal loss in Grid2Lc/+ mice. The up-regulation of pro-caspase-3 in Grid2Lc/+ Purkinje cells is Bax and p53 independent. These results suggest that Grid2Lc/+ granule cell death is dependent on Bax and caspase-3 activation, whereas several pathways can mediate Grid2Lc/+ Purkinje cell death.

Afferent-target cell interactions in the cerebellum: negative effect of granule cells on Purkinje cell development in lurcher mice.

Lurcher (Lc) is a gain-of-function mutation in the delta2 glutamate receptor gene that results in a large, constitutive inward current in the cerebellar Purkinje cells of +/Lc mice. +/Lc Purkinje cells fail to differentiate fully and die during postnatal development. In normal mice, interactions with granule cells promote Purkinje cell dendritic differentiation. Partial destruction of the granule cell population in young +/Lc mice by x irradiation resulted in a significant increase in Purkinje cell dendritic growth and improved cytoplasmic structure but did not prevent Purkinje cell death. These results indicate two components to Purkinje cell abnormalities in +/Lc mice: a retardation/blockade of dendritic development that is mediated by interactions with granule cells and the death of the cell. Thus, the normal trophic effects of granule cell interaction on Purkinje cell development are absent in the +/Lc cerebellum, suggesting that granule cells are powerful regulators of Purkinje cell differentiation.

Survival and prognostic factors of invasive aspergillosis after allogeneic bone marrow transplantation.

To determine prognostic factors for survival in bone marrow transplant recipients with invasive aspergillosis (IA), we retrospectively reviewed 27 IA cases observed in our bone marrow transplantation unit between January 1994 and October 1994. On 30 September 1997, six patients were alive and disease-free. The median survival after IA diagnosis was 36 days. Of eight variables found to be related to survival according to the univariate analysis, graft-versus-host disease (GVHD) status at IA diagnosis (P = .0008) and the cumulative prednisolone dose taken during the week preceding IA diagnosis (CPDlw) (P < .0001) were selected by a backward stepwise Cox regression model. A three-stage classification was established: CPD1w of < or =7 mg/kg (3 of 8 patients died; 60-day survival rate, 88%), CPD1w of >7 mg/kg and no GVHD (9 of 10 patients died; 60-day survival rate, 20%), and CPD1w of >7 mg/kg and active acute grade 2 or more or extensive chronic GVHD (9 of 9 patients died; 30-day survival rate, 0) (P < .0001).

[Caenorhabditis elegans and neuronal death in mammals]. / Caenorhabditis elegans et la mort neuronale chez les mammifères.

The development of the nervous system implies not only the generation of neurons, but also their death. This neuronal death can occur through several mechanisms, one of them being apoptosis. This type of cell death seems to be also implicated in some neurodegenerative diseases. This study of the nematode Caenorhabditis elegans has led to the discovery of several genes controlling apoptosis in neurons. Two of them, the pro-apoptotic ced3 and the anti-apoptotic ced9, have mammalian homologs. The mammalian homologs to Ced9 form the Bcl-2 family and can be either pro-apoptotic or anti-apoptotic. Some of them, Bcl-x, and Bax have been shown to be involved in neuronal death during development in some pathological situations. The first mammalian homolog of Ced3 to be described was the Interleukin-1b Converting Enzymes (ICE). Since then, many other homologs of the proteases Ced3 and ICE have been discovered constituting the Caspases family. These Cysteinyl Aspartate Specific Proteases are pro-apoptotic in many different systems. Several studies using viral or peptidic inhibitors of the Caspases have demonstrated their role in neuronal death in vitro. In vivo, CPP32, a member of the Caspases family, has been shown to be clearly involved in the development of the nervous system. Finally, the analysis of apoptosis in Caenorhabditis elegans has led to the discovery of two families of genes involved in the cascade of events inducing neuronal death in mammals. Indeed, the Caspases seem to be controlled by the Bcl-2 family, as Ced3 is by Ced9.

Absence of cytomegalovirus and Epstein-Barr virus expression in labial salivary glands of patients with chronic graft-versus-host disease.

We investigated in 15 consecutive patients a possible correlation between expression of CMV or EBV in labial salivary gland (LSG) biopsies performed 100 days after allogeneic BMT and subsequent development of chronic GVHD. Three techniques were performed for the detection of each virus: immunohistochemistry, in situ hybridization and PCR. Eleven patients developed chronic GVHD. Histologic examination detected a moderate lymphoid infiltrate (grade 1 according to Sale's score) in LSG biopsy in only one patient. CMV genes or proteins could not be detected in any patients. Likewise, EBV genome or proteins were not detected by in situ hybridization and immunohistochemistry. However, in three of the 15 patients, EBV DNA was detected by PCR in LSG biopsies. Only one of these three patients developed chronic GVHD. Therefore, at the present time, the presence of a lymphoid infiltrate on lip biopsies performed at day 100 post-BMT does not appear to be sensitive enough for the diagnosis or the prediction of the subsequent development of chronic GVHD. Moreover, the absence of EBV and CMV expression in a day-100 LSG biopsy does not preclude the development of chronic GVHD.

Avascular necrosis of bone after allogeneic bone marrow transplantation: clinical findings, incidence and risk factors.

In the present study we describe the incidence, clinical course, and management of avascular necrosis of bone following allogeneic bone marrow transplantation, and identify risk factors related to its development. All patients developing avascular necrosis of bone after allogeneic bone marrow transplantation between January 1974 and September 1992 were included in the analysis and were studied using the Hôpital Saint Louis Bone Marrow Transplant Database and hospital records. 27/727 allogeneic transplant recipients developed avascular necrosis leading to an 8.1% incidence at 5 years, by product limit estimate, ranging from 5% to 11.2%. Symptoms developed 119-1747 d (median 398 d) after transplantation. In these 27 patients a total of 52 joints were affected (mean 1.92 per patient, range 1-7). The hip joint was most often affected (69% of patients). All patients had joint pain that led to diagnosis by means of standard radiographs with or without the help of technetium-99 scans and/or magnetic resonance imaging. All but three patients received steroid therapy for acute graft-versus-host disease. Among 10 factors tested, three were shown to be significantly linked to an increased risk for developing avascular necrosis by multivariate analysis: male gender (relative risk (RR) 4.72, P = 0.002), age older than 16 (RR = 3.87, P = 0.004), and acute graft-versus-host disease requiring steroid therapy (RR = 6.30, P = 0.0002). 10 patients (37%) required joint replacement within 19 months (range 2-42) following diagnosis of avascular necrosis. In conclusion, avascular necrosis of bone is a frequent late complication of allogeneic bone marrow transplantation causing significant morbidity and requiring replacement surgery in one-third of affected patients. In this 18-year single-centre survey, older age, male gender and steroid therapy given for acute graft-versus-host disease were shown to independently increase the risk of avascular necrosis of bone.

Progress in the prevention of cytomegalovirus infection after allogeneic bone marrow transplantation.

There has been substantial progress in preventing and treating CMV infection. Prophylaxis with CMV screened blood products, IVIG and antiviral drugs (high dose acyclovir and/or Ganciclovir) considerably reduce the incidence of CMV disease and nearly eliminate CMV pneumonia after allogeneic BMT.

Distribution of 125I-ferrotransferrin binding sites in the mesencephalon of control subjects and patients with Parkinson's disease.

Iron is abnormally accumulated in the substantia nigra pars compacta of patients with Parkinson's disease (PD). Because neuronal and glial iron uptake seems to be mediated by the binding of ferrotransferrin to a specific high-affinity receptor on the cell surface, the number of transferrin receptors could be altered in this disease. The regional distribution of specific binding sites for human 125I-diferric transferrin has been studied in the mesencephalon, on cryostat-cut sections from autopsy brains of control subjects and parkinsonian patients by in vitro autoradiography. Densities of binding sites were highest in the central gray substance (approximately 10 fmol/mg of tissue equivalent), intermediate in the catecholaminergic cell group A8, superior colliculus, and ventral tegmental area, and almost nonexistent in the substantia nigra. The density of 125I-transferrin binding sites was not significantly different between parkinsonian and control brains in any region analyzed. These results show that in the mesencephalon the regional density of transferrin binding sites is lowest in the dopaminergic cell groups, which are the most vulnerable to PD, and suggest that iron does not accumulate through an increased density of transferrin receptors at the level of the substantia nigra.