Spatial and cell type transcriptional landscape of human cerebellar development

The human neonatal cerebellum is one-fourth of its adult size yet contains the blueprint required to integrate environmental cues with developing motor, cognitive and emotional skills into adulthood. Although mature cerebellar neuroanatomy is well studied, understanding of its developmental origins is limited. In this study, we systematically mapped the molecular, cellular and spatial composition of human fetal cerebellum by combining laser capture microscopy and SPLiT-seq single-nucleus transcriptomics. We profiled functionally distinct regions and gene expression dynamics within cell types and across development. The resulting cell atlas demonstrates that the molecular organization of the cerebellar anlage recapitulates cytoarchitecturally distinct regions and developmentally transient cell types that are distinct from the mouse cerebellum. By mapping genes dominant for pediatric and adult neurological disorders onto our dataset, we identify relevant cell types underlying disease mechanisms. These data provide a resource for probing the cellular basis of human cerebellar development and disease.

Protrusion-Mediated Signaling Regulates Patterning of the Developing Nervous System

During brain development, the tissue pattern and specification are the foundation of neuronal circuit formation. Contact-mediated lateral inhibition is well known to play an important role in determining cell fate decisions in the nervous system by either regulating tissue boundary formation or the classical salt-and-pepper pattern of differentiation that results from direct neighboring cell contacts. In many systems, however, such as the Drosophila notum, Drosophila wing, zebrafish pigmented cells, and zebrafish spinal cord, the differentiation pattern occurs at multiple-cell diameter distances. In this review, we discuss the evidence and characteristics of long-distance patterning mechanisms mediated by cellular protrusions. In the nervous system, cellular protrusions deliver the Notch ligand Delta at long range to prevent cells from differentiating in their vicinity. By temporal control of protrusive activity, this mechanism can pattern differentiation in both space and time.

Delta-Notch Signaling: The Long and The Short of a Neuron's Influence on Progenitor Fates

Maintenance of the neural progenitor pool during embryonic development is essential to promote growth of the central nervous system (CNS). The CNS is initially formed by tightly compacted proliferative neuroepithelial cells that later acquire radial glial characteristics and continue to divide at the ventricular (apical) and pial (basal) surface of the neuroepithelium to generate neurons. While neural progenitors such as neuroepithelial cells and apical radial glia form strong connections with their neighbours at the apical and basal surfaces of the neuroepithelium, neurons usually form the mantle layer at the basal surface. This review will discuss the existing evidence that supports a role for neurons, from early stages of differentiation, in promoting progenitor cell fates in the vertebrates CNS, maintaining tissue homeostasis and regulating spatiotemporal patterning of neuronal differentiation through Delta-Notch signalling.

Basal Protrusions Mediate Spatiotemporal Patterns of Spinal Neuron Differentiation

During early spinal cord development, neurons of particular subtypes differentiate with a sparse periodic pattern while later neurons differentiate in the intervening space to eventually produce continuous columns of similar neurons. The mechanisms that regulate this spatiotemporal pattern are unknown. In vivo imaging in zebrafish reveals that differentiating spinal neurons transiently extend two long protrusions along the basal surface of the spinal cord before axon initiation. These protrusions express Delta protein, consistent with the hypothesis they influence Notch signaling at a distance of several cell diameters. Experimental reduction of Laminin expression leads to smaller protrusions and shorter distances between differentiating neurons. The experimental data and a theoretical model support the proposal that neuronal differentiation pattern is regulated by transient basal protrusions that deliver temporally controlled lateral inhibition mediated at a distance. This work uncovers a stereotyped protrusive activity of newborn neurons that organize long-distance spatiotemporal patterning of differentiation.

Spatiotemporal expansion of primary progenitor zones in the developing human cerebellum

We present histological and molecular analyses of the developing human cerebellum from 30 days after conception to 9 months after birth. Differences in developmental patterns between humans and mice include spatiotemporal expansion of both ventricular and rhombic lip primary progenitor zones to include subventricular zones containing basal progenitors. The human rhombic lip persists longer through cerebellar development than in the mouse and undergoes morphological changes to form a progenitor pool in the posterior lobule, which is not seen in other organisms, not even in the nonhuman primate the macaque. Disruptions in human rhombic lip development are associated with posterior cerebellar vermis hypoplasia and Dandy-Walker malformation. The presence of these species-specific neural progenitor populations refines our insight into human cerebellar developmental disorders.

Rho kinase-dependent apical constriction counteracts M-phase apical expansion to enable mouse neural tube closure

Cellular generation of mechanical forces required to close the presumptive spinal neural tube, the 'posterior neuropore' (PNP), involves interkinetic nuclear migration (INM) and apical constriction. Both processes change the apical surface area of neuroepithelial cells, but how they are biomechanically integrated is unknown. Rho kinase (Rock; herein referring to both ROCK1 and ROCK2) inhibition in mouse whole embryo culture progressively widens the PNP. PNP widening is not caused by increased mechanical tension opposing closure, as evidenced by diminished recoil following laser ablation. Rather, Rock inhibition diminishes neuroepithelial apical constriction, producing increased apical areas in neuroepithelial cells despite diminished tension. Neuroepithelial apices are also dynamically related to INM progression, with the smallest dimensions achieved in cells positive for the pan-M phase marker Rb phosphorylated at S780 (pRB-S780). A brief (2 h) Rock inhibition selectively increases the apical area of pRB-S780-positive cells, but not pre-anaphase cells positive for phosphorylated histone 3 (pHH3⁺). Longer inhibition (8 h, more than one cell cycle) increases apical areas in pHH3⁺ cells, suggesting cell cycle-dependent accumulation of cells with larger apical surfaces during PNP widening. Consequently, arresting cell cycle progression with hydroxyurea prevents PNP widening following Rock inhibition. Thus, Rock-dependent apical constriction compensates for the PNP-widening effects of INM to enable progression of closure.This article has an associated First Person interview with the first authors of the paper.

Un nouveau Cas d’Anomalie constitutionnelle et familiale du Fibrinogène sans Diathese hémorragique

A new family with congenital dysfibrinogenemia without bleeding tendency has been discovered in Nancy. Identical laboratory abnormalities were found in the mother and son plasma: prolongation of thrombin and reptilase clotting time.

The abnormal fibrinogen affects, only a little, the normal plasma fibrinoformation.

The functional characterization of the defect is localized in fibrin monomer aggregation. The release of fibrinopeptides is normal.

The abnormal fibrinogen shows

a) an alteration in glucidic moiety of the molecule with a high level of sialic acid,

b) an disturbance of chromatography on D. E. A. E. cellulose and

c) of the electrophoretic mobility.

Epinephrine administration in non-shockable out-of-hospital cardiac arrest

BACKGROUND

Epinephrine is recommended for the treatment of non-shockable out of hospital cardiac arrest (OHCA) to obtain return of spontaneous circulation (ROSC). Epinephrine efficiency and safety remain under debate.

OBJECTIVE

We propose to describe the association between the cumulative dose of epinephrine and the failure of ROSC during the first 30 min of advanced life support (ALS).

METHODOLOGY

A retrospective observational cohort study using the Paris SAMU 75 registry including all non-traumatic OHCA. All OHCA receiving epinephrine during the first 30 min of ALS were enrolled. Cumulative epinephrine dose given during ALS to ROSC was retrieved from medical reports.

RESULTS

Among 1532 patients with OHCA, 776 (51%) had initial non-shockable rhythm. Fifty-four patients were excluded for missing data. The mean value of cumulative dose of epinephrine was 10 ± 4 mg in patients who failed to achieve ROSC (ROSC-) and 4 ± 3 mg (p = 0.04) for those who achieved ROSC. ROC curve analysis indicated a cut-off point of 7 mg total cumulative epinephrine associated with ROSC- (AUC = 0.89 [0.86-0.92]). Using propensity score analysis including age, sex and no-flow duration, association with ROSC- only remained significant for epinephrine > 7 mg (p ≤10-3, OR [CI95] = 1.53 [1.42-1.65]).

CONCLUSION

An association between total cumulative epinephrine dose administered during OHCA resuscitation and ROSC- was reported with a threshold of 7 mg, best identifying patients with refractory OHCA. We suggest using this threshold in this context to guide the termination of ALS and early decide on the implementation of extracorporeal life support or organ harvesting in the first 30 min of ALS.

Spatial distribution and characterization of non-apical progenitors in the zebrafish embryo central nervous system

Studies of non-apical progenitors (NAPs) have been largely limited to the developing mammalian cortex. They are postulated to generate the increase in neuron numbers that underlie mammalian brain expansion. Recently, NAPs have also been reported in the retina and central nervous system of non-mammalian species; in the latter, however, they remain poorly characterized. Here, we characterize NAP location along the zebrafish central nervous system during embryonic development, and determine their cellular and molecular characteristics and renewal capacity. We identified a small population of NAPs in the spinal cord, hindbrain and telencephalon of zebrafish embryos. Live-imaging analysis revealed at least two types of mitotic behaviour in the telencephalon: one NAP subtype retains the apical attachment during division, while another divides in a subapical position disconnected from the apical surface. All NAPs observed in spinal cord lost apical contact prior to mitoses. These NAPs express HuC and produce two neurons from a single division. Manipulation of Notch activity reveals that neurons and NAPs in the spinal cord use similar regulatory mechanisms. This work suggests that the majority of spinal NAPs in zebrafish share characteristics with basal progenitors in mammalian brains.

Infectious causes of microcephaly: epidemiology, pathogenesis, diagnosis, and management

Microcephaly is an important sign of neurological malformation and a predictor of future disability. The 2015-16 outbreak of Zika virus and congenital Zika infection brought the world's attention to links between Zika infection and microcephaly. However, Zika virus is only one of the infectious causes of microcephaly and, although the contexts in which they occur vary greatly, all are of concern. In this Review, we summarise important aspects of major congenital infections that can cause microcephaly, and describe the epidemiology, transmission, clinical features, pathogenesis, management, and long-term consequences of these infections. We include infections that cause substantial impairment: cytomegalovirus, herpes simplex virus, rubella virus, Toxoplasma gondii, and Zika virus. We highlight potential issues with classification of microcephaly and show how some infants affected by congenital infection might be missed or incorrectly diagnosed. Although Zika virus has brought the attention of the world to the problem of microcephaly, prevention of all infectious causes of microcephaly and appropriately managing its consequences remain important global public health priorities.

Microtubules, polarity and vertebrate neural tube morphogenesis

Microtubules (MTs) are key cellular components, long known to participate in morphogenetic events that shape the developing embryo. However, the links between the cellular functions of MTs, their effects on cell shape and polarity, and their role in large-scale morphogenesis remain poorly understood. Here, these relationships were examined with respect to two strategies for generating the vertebrate neural tube: bending and closure of the mammalian neural plate; and cavitation of the teleost neural rod. The latter process has been compared with 'secondary' neurulation that generates the caudal spinal cord in mammals. MTs align along the apico-basal axis of the mammalian neuroepithelium early in neural tube closure, participating functionally in interkinetic nuclear migration, which indirectly impacts on cell shape. Whether MTs play other functional roles in mammalian neurulation remains unclear. In the zebrafish, MTs are important for defining the neural rod midline prior to its cavitation, both by localizing apical proteins at the tissue midline and by orienting cell division through a mirror-symmetric MT apparatus that helps to further define the medial localization of apical polarity proteins. Par proteins have been implicated in centrosome positioning in neuroepithelia as well as in the control of polarized morphogenetic movements in the neural rod. Understanding of MT functions during early nervous system development has so far been limited, partly by techniques that fail to distinguish 'cause' from 'effect'. Future developments will likely rely on novel ways to selectively impair MT function in order to investigate the roles they play.

Par3 controls neural crest migration by promoting microtubule catastrophe during contact inhibition of locomotion

There is growing evidence that contact inhibition of locomotion (CIL) is essential for morphogenesis and its failure is thought to be responsible for cancer invasion; however, the molecular bases of this phenomenon are poorly understood. Here we investigate the role of the polarity protein Par3 in CIL during migration of the neural crest, a highly migratory mesenchymal cell type. In epithelial cells, Par3 is localised to the cell-cell adhesion complex and is important in the definition of apicobasal polarity, but the localisation and function of Par3 in mesenchymal cells are not well characterised. We show in Xenopus and zebrafish that Par3 is localised to the cell-cell contact in neural crest cells and is essential for CIL. We demonstrate that the dynamics of microtubules are different in different parts of the cell, with an increase in microtubule catastrophe at the collision site during CIL. Par3 loss-of-function affects neural crest migration by reducing microtubule catastrophe at the site of cell-cell contact and abrogating CIL. Furthermore, Par3 promotes microtubule catastrophe by inhibiting the Rac-GEF Trio, as double inhibition of Par3 and Trio restores microtubule catastrophe at the cell contact and rescues CIL and neural crest migration. Our results demonstrate a novel role of Par3 during neural crest migration, which is likely to be conserved in other processes that involve CIL such as cancer invasion or cell dispersion.

Cytokinesis of neuroepithelial cells can divide their basal process before anaphase

Neuroepithelial (NE) cells, the primary stem and progenitor cells of the vertebrate central nervous system, are highly polarized and elongated. They retain a basal process extending to the basal lamina, while undergoing mitosis at the apical side of the ventricular zone. By studying NE cells in the embryonic mouse, chick and zebrafish central nervous system using confocal microscopy, electron microscopy and time-lapse imaging, we show here that the basal process of these cells can split during M phase. Splitting occurred in the basal-to-apical direction and was followed by inheritance of the processes by either one or both daughter cells. A cluster of anillin, an essential component of the cytokinesis machinery, appeared at the distal end of the basal process in prophase and was found to colocalize with F-actin at bifurcation sites, in both proliferative and neurogenic NE cells. GFP-anillin in the basal process moved apically to the cell body prior to anaphase onset, followed by basal-to-apical ingression of the cleavage furrow in telophase. The splitting of the basal process of M-phase NE cells has implications for cleavage plane orientation and the relationship between mitosis and cytokinesis.

Positive and negative regulations by FGF8 contribute to midbrain roof plate developmental plasticity

The roof plate (RP) of the midbrain shows an unusual plasticity, as it is duplicated or interrupted by experimental manipulations involving the mid/hindbrain organizer or FGF8. In previous experiments, we have found that FGF8 induces a local patterning center, the isthmic node, that is essential for the local development of a RP. Here, we show that the plasticity of the midbrain RP derives from two apparently antagonistic influences of FGF8. On the one hand, FGF8 widens beyond the neural folds the competence of the neuroepithelium to develop a RP by inducing the expression of LMX1B and WNT1. Ectopic overexpression of these two factors is sufficient to induce widely the expression of markers of the mature RP in the midbrain. On the other hand,FGF8 exerts a major destabilizing influence on RP maturation by controlling signaling by members of the TGFβ superfamily belonging to the BMP, GDF and activin subgroups. We show in particular that FGF8 tightly modulates follistatin expression, thus progressively restraining the inhibitory influence of activin B on RP differentiation. These regulations, together with FGF8 triggered apoptosis, allow the formation of a RP progress zone at some distance from the FGF8 source. Posterior elongation of the RP is permitted when the source of FGF8 withdraws. Growth of the posterior midbrain neuroepithelium and convergent extension movements induced by FGF8 both contribute to increase the distance between the source of FGF8 and the maturing RP. Normally, the antagonistic regulatory interactions spread smoothly across the midbrain. Plasticity of midbrain RP differentiation probably results from an experimentally induced imbalance between regulatory pathways.

Does the isthmic organizer influence D/V patterning of the midbrain?

Early brain and spinal cord regionalization along the dorsoventral axis are thought to be governed by similar mechanisms. Subsequently, the size of the alar plate of the neural tube increases dramatically in the midbrain and anterior forebrain, compared to the spinal cord. This suggests that additional mechanisms may be required to refine A/P and D/V patterning in these structures. The isthmic organizer is a signaling center that controls both growth and patterning in the midbrain and anterior hindbrain through the production of several secreted molecules, in particular FGF8. Several studies have indicated that the isthmic organizer is involved in the positioning and development of the midbrain roof and floor plates, the two structures that respectively mark the dorsal and ventral axis of the neural tube. It remains unclear whether its influence on axis formation in the midbrain is a consequence of a more general function of the isthmic organizer/FGF8 as a modulator of DV patterning or if selection of an axis is a necessary and general by-product of its organizing function not directly related to D/V patterning. In this paper, we review the current data supporting each possibility.

Regionalization of the isthmic and cerebellar primordia

The complex migrations of neurons born in the dorsal neural tube of the isthmic and rhombomere l (rl) domains complicate the delineation of the cerebellar primordium. We show that Purkinje cells (P) are likely generated over a wide territory before gathering in the future cerebellar primordium under the developing external granular layer. Later expansion of the cerebellum over a restricted ependymal domain could rely on mutual interations between P cells and granule cell progenitors (GCP). P are attracted by GCP and in turn stimulate their proliferation, increasing the surface of the developing cortex. At later stages, regionalization of the developing and adult cerebellar cortex can be detected through regional variations in the distribution of several P cell markers. Whether and how the developmental and adult P subtypes are related is still unknown and it is unclear if they delineate the same sets of cerebellar subdivisions. We provide evidence that the early P regionalization is involved in intrinsic patterning of the cerebellar primordium, in particular it relate to the organization of the corticonuclear connection. We propose that the early P regionalization provides a scaffold to the mature P regionalization but that the development of functional afferent connections induces a period of P plasticity during which the early regional identity of P could be remodeled.

The isthmic neuroepithelium is essential for cerebellar midline fusion

The cerebellum comprises a medial domain, called the vermis, flanked by two lateral subdivisions, the cerebellar hemispheres. Normal development of the vermis involves fusion of two lateral primordia on the dorsal midline. We investigated how the cerebellum fuses on the midline by combining a study of mid/hindbrain cell movements in avian embryos with the analysis of cerebellar fusion in normal and mutant mouse embryos. We found that, in avian embryos,divergent cell movements originating from a restricted medial domain located at the mid/hindbrain boundary produce the roof plate of the mid/hindbrain domain. Cells migrating anteriorly from this region populate the caudal midbrain roof plate whereas cells migrating posteriorly populate the cerebellar roof plate. In addition, the adjacent paramedial isthmic neuroepithelium also migrates caudalward and participates in the formation of the cerebellar midline region. We also found that the paramedial isthmic territory produces two distinct structures. First, the late developing velum medullaris that intervenes between the vermis and the midbrain, and second, a midline domain upon which the cerebellum fuses. Elimination or overgrowth of this isthmic domain in Wnt1sw/sw and En1+/Otx2lacZ mutant mice, respectively, impair cerebellar midline fusion. Because the isthmus-derived midline cerebellar domain displays a distinct expression pattern of genes involved in BMP signaling, we propose that the isthmus-derived cells provide both a substratum and signals that are essential for cerebellar fusion.

The isthmic organizer links anteroposterior and dorsoventral patterning in the mid/hindbrain by generating roof plate structures

During vertebrate development, an organizing signaling center, the isthmic organizer, forms at the boundary between the midbrain and hindbrain. This organizer locally controls growth and patterning along the anteroposterior axis of the neural tube. On the basis of transplantation and ablation experiments in avian embryos, we show here that, in the caudal midbrain, a restricted dorsal domain of the isthmic organizer, that we call the isthmic node, is both necessary and sufficient for the formation and positioning of the roof plate, a signaling structure that marks the dorsal midline of the neural tube and that is involved in its dorsoventral patterning. This is unexpected because in other regions of the neural tube, the roof plate has been shown to form at the site of neural fold fusion, which is under the influence of epidermal ectoderm derived signals. In addition, the isthmic node contributes cells to both the midbrain and hindbrain roof plates, which are separated by a boundary that limits cell movements. We also provide evidence that mid/hindbrain roof plate formation involves homeogenetic mechanisms. Our observations indicate that the isthmic organizer orchestrates patterning along the anteroposterior and the dorsoventral axis.

Energy saving in flight formation

Many species of large bird fly together in formation, perhaps because flight power demands and energy expenditure can be reduced when the birds fly at an optimal spacing, or because orientation is improved by communication within groups. We have measured heart rates as an estimate of energy expenditure in imprinted great white pelicans (Pelecanus onocrotalus) trained to fly in 'V' formation, and show that these birds save a significant amount of energy by flying in formation. This advantage is probably a principal reason for the evolution of flight formation in large birds that migrate in groups.

Development of electronic personal neutron dosemeters: a European cooperation

The European Commission recently sponsored an international research and development project, in which three 'active' personal neutron dosemeters were developed. Comparative irradiation experiments showed good results with respect to sensitivity and energy dependence of the response.

Hemorheological and hemostatic parameters in children with nephrotic syndrome undergoing steroid therapy

Disturbances in hemostatic and hemorheological parameters have been investigated in a group of 29 children with nephrotic syndrome: 23 children classified as steroid-sensitive and 6 as steroid-resistant. Studies were performed before prednisone treatment and 3 weeks later, after initiation of steroid therapy. Before treatment, the alterations in hemostatic system involved moderate thrombocytosis with spontaneous aggregation in 19 patients. High levels of fibrinogen, factor VIII, Willebrand factor, protein C, protein S and alpha 2-macroglobulin (alpha 2M) were observed. Factor XII and alpha 1-antitrypsin (alpha 1AT) were lower than normal. Antithrombin III (ATIII) level was normal in the majority of patients. A plasma and blood hyperviscosity syndrome was also observed as well as an increase in erythrocyte aggregation. During treatment, an improvement in the hemostatic parameters was observed in the patients who responded to prednisone. The expected increase in factor VIII (frequently described in the literature) was not observed, while there was a significant increase in protein C. In the steroid-resistant patients, the only significant changes observed were decreased fibrinogen and increased protein C. The hemorheological parameters showed a tendency towards normality regardless of whether or not the treatment provided remission of NS. The relationship between hemorheological and hemostatic factors changes are discussed.

Interlaboratory evaluation of methods for the assay of Protein C in purified concentrates

Determination of the quantity and activity of the Protein C molecule is of the utmost importance in highly purified concentrates prepared for replacement therapy. A multicenter study was undertaken to evaluate the comparability and accuracy of Protein C assays from commercial sources. Significant between-assay and interlaboratory differences were found for both functional and immunological assays. The interlaboratory variability is explained in part by the use of different control plasmas. The results also indicate the importance of the diluent used. This study emphasizes the need for standardized methods for determining the characteristics of Protein C concentrates.

[Which assessment of coagulation, for which operation?]

Patient's bleeding history is an important part of preoperative evaluation but must be associated with hemostatic tests. The choice in between these different hemostatic tests will be made according to the knowledge of the bleeding history and; the type of surgery planned. In case of hemostatic abnormality, additional tests can be performed in order to determine a more precise state of the patient's hemostatic dysfunction. However, complete preoperative hemostatic evaluation (including patient's bleeding history and blood tests) may not entirely avoid per and post-operative hemostatic complications. Indeed, there is no absolute correlation between hemostatic screening and bleeding or thrombosis risks. Some other factors, completely independent from hemostatic function, such as shock, surgical bleeding, anoxia... may intervene.

[Immunological status of hemophiliacs: study of blood T-lymphocyte populations, serum immunoglobulins, and the prevalence of anti-LAV antibodies]

Blood T-lymphocyte subsets and serum immunoglobulin levels were studied in a group of 52 haemophiliacs (44 patients with haemophilia A and 8 patients with haemophilia B). None of the patients had AIDS or belonged to any AIDS high-risk group. Patients were exclusively treated with clotting fractions obtained from healthy volunteers in metropolitan France. As compared to a group of 52 normal donors, haemophiliacs had increased numbers of suppressor lymphocytes, which resulted in depressed helper/suppressor (H/S) ratios, and increased levels of serum IgG and IgA. 21 haemophiliacs (40,3%) had a H/S ratio less than 1.4. Among patients with haemophilia A a higher mean IgG level was found in patients presenting lymphadenopathy. Decreased mean H/S ratio and increased mean serum IgG level were found in patients receiving more than 50 000 U of factor VIII during the 2 years preceding the study. No striking difference in mean serum IgG, IgA and IgM levels was found in patients with haemophilia A when H/S ratios were higher and lower than 1.4 respectively. As AIDS and immunological abnormalities among haemophiliacs probably share a common viral origin, this study emphasize the need to discourage blood donation from donors who belong to any AIDS high-risk group, and to screen sera from the blood donor population for antibodies to LAV/HTLV III.

Prevalence of antibodies to lymphadenopathy-AIDS virus in French haemophiliacs

49 French haemophiliacs (haemophilia A: 41 patients; haemophilia B: 8 patients) were serologically testes for lymphadenopathy-AIDS virus antibodies: 10 patients (20.4%) were seropositive including 9 (21.9%) with haemophilia A and 1 (12.5%) with haemophilia B. Among haemophiliacs A, seropositive patients received significantly larger amounts of factor VIII concentrate during the 2 years preceding the study.

[Prevalence of anti-LAV antibodies in hemophiliacs, correlation with the immunological state]

49 french haemophiliacs (haemophilia A: 41 patients; haemophilia B: 8 patients) were serologicaly tested for LAV antibodies: 10 patients (20.4%) were seropositive including 9 (21.9%) with haemophilia A and 1 (12,5%) with haemophilia B. Between seronegative and seropositive patients total lymphocyte and T-lymphocyte sub-populations counts were not significantly different. The mean serum IgG level was higher and palpable lymphadenopathy more frequently encountered among seropositive patients.

[Blood T lymphocyte populations in the hemophiliac]

We have studied a group of 31 hemophiliac patients (hemophilia A: 26 patients, hemophilia B: 5 patients); 29 healthy men were used as controls. Hemophiliac patients had increased percentages of suppressor T-lymphocytes and depressed T4/T8 ratios. These abnormalities were found to be significantly correlated with the amount of F VIII used per year.

[Practical value of the determination of urinary fibrin degradation products in the early management of renal transplants]

We studied daily urinary excretion of fibrin degradation products (UFDP) during the first month following renal transplantation in 31 patients using the Merskey technique. After the 48 first hours a rise of UFDP was observed in 3 circumstances: 1) acute rejection: twenty-four acute rejections were observed in twenty-two patients. The increase of UFDP was constant. It preceeded the clinical diagnosis of rejection in 63 p. 100 of the patients. It has a predictive value in all cases. 2) Severe urinary infection. In 5 patients with urologic complications UFDP rose markedly. 3) Macroscopic hematuria. In 2 patients with gross hematuria very high rates of excretion were observed.

[Practical interest of the determination of urinary fibrin degradation products in the early monitoring of kidney transplants]

We studied daily urinary excretion of fibrin degradation products (UFDP) during the first month following renal transplantation in 31 patients using the Merskey technique. Passed the 48 first hours a rise of UFDP was observed in 3 circumstances: 1) acute rejection: twenty four acute rejections were observed in twenty two patients. The increase of UFDP was constant. It preceded the clinical diagnosis of rejection in 63 p. 100 of the patients. It has a predictive value in all cases. 2) Severe urinary infection. In 5 patients with urologic complications UFDP rose markedly. 3) Macroscopic hematuria. In 2 patients with gross hematuria very high rates of excretion were observed.

HLA typing in a new family with Fletcher factor deficiency

In a nonrelated white family, the Fletcher factor level in the father was 0.41 U/ml and in the mother, 0.30 U/ml (controls, 0.75-1.25 U/ml). One sibling with recurrent epistaxis had a level of 0.012 U/ml, whereas the other without tendency to spontaneous bleeding had levels between 0.75 and 0.32 U/ml. This suggests autosomal recessive transmission with clinical symptoms when the defect is homozygous. HLA antigens were studied to determine whether characters of the histocompatibility system and this defect are linked: we determined that the gene(s) of the disease is (are) not shared on the HLA complex.

Bond strength of three orthodontic adhesives

A method was devised to study the bond strength of direct-bonding orthodontic adhesives. A shear load was applied parallel to the tooth-adhesive-bracket interface by means of an Instron Universal Testing Machine. The bond strength was found to increase for some products after 27 days. However, no significant differences could be detected 1 day after placement. The interface was studied to determine the mode of failure. In all cases bond failure occurred as mixed adhesive-cohesive phenomena.

Recurring thrombo-embolic accidents caused by family-related deficiency of the fibrinolysis system

Several members of the same family underwent examinations on the coagulation and fibrinolysis systems after recurring thrombo-embolic disease was observed in one of the members of the family. The results of biological examinations revealed normal coagulation factors, but a high level of plasminogen activation inhibitors accompanied by an increase in platelet aggregation was observed. These results are compared with the few similar cases reported by other authors. The exact part played in this particular case by the platelets and the inhibitor in the patient's predisposition to venous thrombosis and the spread of the disease is discussed. It would seem that the platelet abnormality merely accompanys the increase in inhibitors which is passed on by recessive autosomal transmission. The authors consider that in all cases of thrombosis, particularly recurring thrombosis, an investigation, comprising a study of the fibrinolysis factors and particularly the inhibitors, must be carried out on the patient's close family.

[Acquired coagulation inhibitors. 10 cases (author's transl)]

A circulating anticoagulant with antiprothrombinase activity was detected in 10 patients, 4 of whom had systemic lupus erythematosus. Clinically, haemorrhages occurred only in patients with associated thrombopenia; some developed thrombosis. Recalcification time and activated partial thromboplastin time were prolonged in the patients' plasma and in mixed patients' and control plasma. In 5 cases the anticoagulant was isolated by chromatography as IgG or IgM.

[Systemic lupus erythematosus manifested by thrombophlebitis of the lower limbs]

The diagnosis of systemic lupus erythematosus was made in a 9 year old boy who had presented two months earlier with an extensive thrombosis of the inferior vena cava and femoral veins. Haemostatic abnormalities were detected as follows: a moderate thrombocytopenia, increased platelet aggregation and stickiness, and a circulating anticoagulant (antithromboplastin).

[Acute renal failure and consumption coagulopathy in the puerperium]

Disseminated intravascular coagulation accompanied 18% of cases of acute renal failure during puerperal disorders. We studied in particular 31 cases of disseminated intravascular coagulation with renal failure due to obstetric disorders : 12 post-abortion infections, 3 retentions of a dead foetus, 5 infections, 6 cases of toxemia, 2 retroplacental hemorrhages, two hemorrhages during the third stage, one uremohemolytic syndrome. For diagnosis one relies on the clinical data (bleeding, purpura, shock, hemolysis, visceral involvement) and laboratory data, (coagulation should be supervised throughout the course). The renal lesions are either cortical necrosis, or interstitial nephritis. The analogies with experimental phenomena suggest a human equivalent of the Schwartzmann-Sanarelli syndrome.