The DDHD2-STXBP1 interaction mediates long-term memory via generation of saturated free fatty acids.

The phospholipid and free fatty acid (FFA) composition of neuronal membranes plays a crucial role in learning and memory, but the mechanisms through which neuronal activity affects the brain's lipid landscape remain largely unexplored. The levels of saturated FFAs, particularly of myristic acid (C14:0), strongly increase during neuronal stimulation and memory acquisition, suggesting the involvement of phospholipase A1 (PLA1) activity in synaptic plasticity. Here, we show that genetic ablation of the PLA1 isoform DDHD2 in mice dramatically reduces saturated FFA responses to memory acquisition across the brain. Furthermore, DDHD2 loss also decreases memory performance in reward-based learning and spatial memory models prior to the development of neuromuscular deficits that mirror human spastic paraplegia. Via pulldown-mass spectrometry analyses, we find that DDHD2 binds to the key synaptic protein STXBP1. Using STXBP1/2 knockout neurosecretory cells and a haploinsufficient STXBP1+/- mouse model of human early infantile encephalopathy associated with intellectual disability and motor dysfunction, we show that STXBP1 controls targeting of DDHD2 to the plasma membrane and generation of saturated FFAs in the brain. These findings suggest key roles for DDHD2 and STXBP1 in lipid metabolism and in the processes of synaptic plasticity, learning, and memory.

Claudin-5 binder enhances focused ultrasound-mediated opening in an in vitro blood-brain barrier model.

Rationale: The blood-brain barrier (BBB) while functioning as a gatekeeper of the brain, impedes cerebral drug delivery. An emerging technology to overcome this limitation is focused ultrasound (FUS). When FUS interacts with intravenously injected microbubbles (FUS+MB), the BBB opens, transiently allowing the access of therapeutic agents into the brain. However, the ultrasound parameters need to be tightly tuned: when the acoustic pressure is too low there is no opening, and when it is too high, tissue damage can occur. We therefore asked whether barrier permeability can be increased by combining FUS+MB with a second modality such that in a clinical setting lower acoustic pressures could be used. Methods: Given that FUS+MB achieves BBB opening in part by disruption of tight junction (TJ) proteins such as claudin-5 of brain endothelial cells, we generated a stable MDCK (Madin-Darby Canine Kidney) II cell line (eGFP-hCldn5-MDCK II) that expresses fluorescently tagged human claudin-5. Two claudin-5 binders, the peptide mC5C2 and cCPEm (truncated form of an enterotoxin), reported previously to weaken the barrier, were synthesized and assessed for their abilities to enhance the permeability of cellular monolayers. We then performed a comparative analysis of single and combination treatments, measuring transendothelial electrical resistance (TEER) and cargo leakage, combined with confocal image analysis. Results: We successfully generated a novel cell line that formed functional monolayers as validated by an increased TEER reading and a low (< 0.2%) permeability to sodium fluorescein (376 Da). We found that the binders exerted a time- and concentration-dependent effect on barrier opening when incubated over an extended period, whereas FUS+MB caused a rapid opening followed by recovery after 12 hours within the tested pressure range. Importantly, preincubation with cCPEm prior to FUS+MB treatment resulted in greater barrier opening compared to either FUS+MB or cCPEm alone as measured by reduced TEER values and an increased permeability to fluorescently labelled 40 kDa dextran (FD40). Conclusion: The data suggest that pre incubation with clinically suitable binders to TJ proteins may be a general strategy to facilitate safer and more effective ultrasound-mediated BBB opening in cellular and animal systems and potentially also for the treatment of human diseases of the brain.

Left Diaphragm Laceration Due to Cardiopulmonary Resuscitation.

External cardiac massage is the essential life-saving gesture for the management of any cardiac arrest. Since the 1960s, many recommendations have been published to improve the effectiveness of chest compressions alongside the development of automated systems intended to maximize the chances of survival. The use of these manual and/or instrumental techniques can cause secondary injuries, of which rib fractures are the most commonly observed by forensic pathologists. However, a comprehensive review of the literature seldom highlights reports of injuries to the abdomen, even less so to the diaphragm. In this observation, an iatrogenic left diaphragmatic laceration for the first time is described, as a result of manual and instrumental cardiopulmonary resuscitation, in a victim from an intrathoracic wound caused by a bladed weapon.

Specific Characteristics of Injuries Inflicted by Claw Hammer.

Claw hammers have the specific characteristic of having two distinct ends: one a flat head of variable form, the other bifurcated. So the use of this tool as a blunt instrument will cause varying injuries. The authors present two clinical cases of assault with a claw hammer. Examinations revealed two types of wound. A first injury composed of integumentary lacerations and underlying bone injuries in terms of "shape" suggested the use of a blunt instrument. A second injury made up of damage showing two parallel wounds or two wounds located one in the extension of the other suggested the use of an object with a bifurcated end. The combination of both types of injury should alert examiners to the possibility of the use of a claw hammer in causing the injuries in order to help direct investigators in their investigations and in the search for the weapon used.

Ontogenesis of the extra-bulbar olfactory pathway in Xenopus laevis.

Although the development, anatomy, and physiology of the vertebrate olfactory system are fairly well understood, there is still no clear definition of the terminal nerve complex acknowledged by all. Among the most debated matters is whether or not the extrabulbar projections found in anamniotes should or should not be considered part of the terminal nerve complex. In this context, we investigated the early development of the extrabulbar pathway in Xenopus larvae from placodal differentiation to postmetamorphic stages. We showed that the extrabulbar fibers become visible around Stage 42 and are conserved throughout metamorphosis. We confirmed previous reports concerning their central projection patterns. In addition, we showed that these fibers originate from two types of cell bodies located in the olfactory epithelium at premetamorphic stages. Furthermore, in postmetamorphic animals, we showed that the extrabulbar axons originated from both aquatic and aerial cavities. Retrograde tracing experiment also revealed densifications evocating cell bodies along the extrabulbar axons, distributed at different positions along the olfactory nerve depending on the stages of development. These densifications were observed closer to the periphery early in development and always closer to the olfactory bulb up to the metamorphic climax. We discuss these results in light of the latest theories and more recent reports.

Chemoattractant axon guidance cues regulate de novo axon trajectories in the embryonic forebrain of zebrafish.

The development of axon tracts in the early vertebrate brain is controlled by combinations of soluble, membrane-bound and extracellular matrix molecules. How these multiple and sometimes conflicting guidance cues are integrated in order to establish stereotypical pathways remains to be determined. We show here that when interactions between the chemoattractive signal Netrin1a and its receptor Dcc are suppressed using a loss-of-function approach, a novel axon trajectory emerges in the dorsal diencephalon. Axons arising from a subpopulation of telencephalic neurons failed to project rostrally into the anterior commissure in the absence of either Netrin1a or Dcc. Instead these axons inappropriately exited the telencephalon and ectopically coursed caudally into virgin neuroepithelium. This response was highly specific since loss-of-function of Netrin1b, a paralogue of Netrin1a, generated a distinct phenotype in the rostral brain. These results show that a subpopulation of telencephalic neurons, when freed from long-range chemoattraction mediated by Netrin1a-Dcc interactions, follow alternative instructive cues that lead to creation of an ectopic axon bundle in the diencephalon. This work provides insight into how integration of multiple guidance signals defines the initial scaffold of axon tracts in the embryonic vertebrate forebrain.

Cryptic organisation within an apparently irregular rostrocaudal distribution of interneurons in the embryonic zebrafish spinal cord.

The molecules and mechanisms involved in patterning the dorsoventral axis of the developing vertebrate spinal cord have been investigated extensively and many are well known. Conversely, knowledge of mechanisms patterning cellular distributions along the rostrocaudal axis is relatively more restricted. Much is known about the rostrocaudal distribution of motoneurons and spinal cord cells derived from neural crest but there is little known about the rostrocaudal patterning of most of the other spinal cord neurons. Here we report data from our analyses of the distribution of dorsal longitudinal ascending (DoLA) interneurons in the developing zebrafish spinal cord. We show that, although apparently distributed irregularly, these cells have cryptic organisation. We present a novel cell-labelling technique that reveals that DoLA interneurons migrate rostrally along the dorsal longitudinal fasciculus of the spinal cord during development. This cell-labelling strategy may be useful for in vivo analysis of factors controlling neuron migration in the central nervous system. Additionally, we show that DoLA interneurons persist in the developing spinal cord for longer than previously reported. These findings illustrate the need to investigate factors and mechanisms that determine "irregular" patterns of cell distribution, particularly in the central nervous system but also in other tissues of developing embryos.

Organ donation in France: legislation, epidemiology and ethical comments.

The Bioethics Laws revised in 2004 have defined rules concerning organ donation and transplantation. They have also permitted the creation of the French Biomedicine Agency which guarantees the right of enforcement. In France there are three situations in which organs may be harvested: from cadaveric donors, from living donors and, since 2005, from non heart beating donors. Organ harvesting from cadaveric donors is permissible if the deceased did not make known his refusal during his lifetime (this may be recorded in the national registry set up for this purpose). The rule of presumed consent also applies in the case of organs taken after cardiac arrest. With regard to organ harvesting from living persons, a panel of experts is required to give approval. The recipient's spouse, brothers or sisters, sons or daughters, grandparents, uncles or aunts and first cousins may be authorised to donate organs, as well as the spouse of the recipient's father or mother. The donor may be any person who provides proof of having lived with the recipient for at least two years. Some ethical questions will need to be resolved; for example the relevance of maintaining the EEG for brain death diagnosis, enforcement of the law on presumed consent, the real nature of the will of living donors and the definition of death.

[Recovery of transportable organs after cardiac arrest]. / Prélèvements d'organes sur donneurs décédés après arrêt cardiaque.

The transplant of an allograft after cardiac arrest has been allowed in France since 2005 (decree of 2 august 2005: art R.1232-4-1, 2 and 3 of the public health code). Recently, according to the international scale, 4 situations that could lead to the realization of transplantable organs after cardiac arrest were identified according to a classification called "Maastricht" which describes the potential donors. In France the donors of class III (cessation of all medical care) were excluded. Ethical questions concerning this new practice come up. Are criteria adopted to define death enough sure? What is the place of non-heart beating donor transplantation with new technical resuscitation as extracorporeal life support for prolonged cardiac arrest? How does family and medical staff live this protocol? Despite this, non heart-beating donor kidney transplants offer the opportunity to compensate for the growing discrepancy between supply and demand for donor kidneys. Results from foreign studies have shown that they have the same survival and long term function as kidneys from traditional brain-stem dead donors. This practice is defined by legislation and supervised by the "Agence de la biomédecine" which guarantees technical efficiency and respect of ethics.

Practitioner sex abuse: occurrence, prevention and disciplinary sanction.

Studies put forward figures for male practitioner sex abuse of around ten per cent. This practice, which is contrary to medical ethics, is highly reprehensible in ethical terms. The assaults range from uninvited meddling in patients' sexual lives to proven rape and inappropriate touching. The majority of this type of abuse is perpetrated by psychiatrists, but in more recent times a growing number of cases have been uncovered involving general practitioners or obstetric gynaecologists. For the most part, the abusers are men, aged between 45 and 64, who are insufficiently trained in terms of the 'practitioner-patient' relationship, or who are suffering from a mental pathology or who are in a situation of personal or professional crisis. Raising awareness of this issue is the driving force behind the implementation of prevention strategies, based on initial and ongoing training for practitioners in France, whistle-blowing on fellow practitioners in the United States and professional help in Canada. Disciplinary sanctions are more severe than those given within the framework of non-sexual misconduct in the United States. In France, the Order of Practitioners does not appear to be taking its role of defending patients seriously, since it seldom issues anything more substantial than minor penalties.

Women who kill their children.

UNLABELLED: The killing of a newborn on the day of its birth is known as neonaticide. A child aged 1 through 16 has a different role in the family, and their murder is perceived differently. We would expect mothers charged with filicide to be drawn from a slightly different population than other child-killing mothers. METHOD: Our study was carried out at the Institute of Forensic Medicine in Angers over a 10-year period. All the victims were autopsied at the Institute of Forensic Medicine in Angers. Information concerning the mothers was collected from forensic medical files, police reports, and legal files. Interviews and forensic psychiatric examinations were available for consultation. RESULTS: Our study concerns 17 observations of child-killing mothers and 19 child autopsies. In 2 cases, the issue was in fact a double murder, with the mother killing all the siblings. The mean age was 3.5 years for victims and 29.5 years for the women. The majority of the mothers were married or lived with their partners. They often had an occupation. Generally the economic status was average. Head trauma, strangulation, suffocation, and drowning were the most frequent means of filicide. However, some mothers used more active methods such as striking and shooting. Disturbed or disturbing behavior was documented in 15 perpetrators. Seven women tried to commit suicide. It was often possible to identify apparent motivation for the offense. DISCUSSION: In our study, we can distinguish 2 types of killer mothers. We distinguished a first group made up of 5 mothers. These 5 women killed their children in a general context of abused children and present similarities with the neonaticide mothers (young, immature). The other group of filicide mothers is different. They are generally older, married, and employed. The crime is usually premeditated, committed with the direct use of hands and sometimes very violent. To understand the motives or the source of the impulse to kill, we can use a classification such as Resnick's classification: mothers from the first group fall within the framework of accidental filicides: the risk and prevention factors are those of infanticide and ill treatment. For the other mothers, we can distinguish altruistic filicides (8 cases) and spouse revenge filicides (2 cases). Few of the mothers suffered from real psychiatric problems; however, most of them presented troubles which could have been taken into account. A lot of women showed signs of suicidal tendencies prior to the event, displaying aggressive and angry behavior. In general, suicide attempts tend to prevail. These offenders act out of an acute sensitivity to social regulation. A variety of psychosocial stresses appears to have been a major factor. These stresses include lack of social or marital support, economic difficulties, family stress, and unrealistic expectations of motherhood. The precipitating stress may have been a dispute. Prevention begins with the identification of potential perpetrators. Therefore, medical doctors have a significant role in relation to the prevention of child murder.

Glial fibrillary acidic protein and vimentin expression in the frog olfactory system during metamorphosis.

In the present study, we investigated glial cell organization in the olfactory system of adult and tadpole Xenopus laevis using glial fibrillary acidic protein and vimentin antibodies. Our results showed for the first time that glial fibrillary acidic protein was strongly expressed at the level of the olfactory nerve from tadpole to adult and was likely to be expressed by ensheathing glia. In the olfactory bulb, the nerve layer was stained, and no staining was observed in glomeruli. By contrast, vimentin decorated radial glia in the bulb but faintly stained the olfactory nerve. Interestingly, glial fibrillary acidic protein and vimentin presented complementary staining patterns, with glial fibrillary acidic protein being expressed in the peripheral olfactory system and vimentin being expressed in the central part of the olfactory system.

3D atlas describing the ontogenic evolution of the primary olfactory projections in the olfactory bulb of Xenopus laevis.

The adult Xenopus presents the unique capability to smell odors both in water and air thanks to two different olfactory pathways. Nevertheless, the tadpole can initially perceive only water-borne odorants, as the olfactory receptor neurons (ORN) that will detect air-borne odorants develop later. Such a phenomenon requires major reorganization processes. Here we focused on the precise description of the neuroanatomical modifications occurring in the olfactory bulb (OB) of the tadpole throughout metamorphosis. Using both carbocyanine dyes and lectin staining, we investigated the evolution of ORN projection patterns into the OB from Stages 47 to 66, thus covering the period of time when all the modifications take place. Although our results confirm previous works (Reiss and Burd [1997] Semin Cell Dev Biol 8:171-179), we showed for the first time that the main olfactory bulb (MOB) is subdivided into seven zones at Stage 47 plus the accessory olfactory bulb (AOB). These seven zones receive fibers dedicated to aquatic olfaction ("aquatic fibers") and are conserved until Stage 66. At Stage 48 the first fibers dedicated to the aerial olfaction constitute a new dorsomedial zone that grows steadily, pushing the seven original zones ventrolaterally. Only the part of the OB receiving aquatic fibers is fragmented, reminiscent of the organization described in fish. This raises the question of whether such an organization in zones constitutes a plesiomorphy or is linked to aquatic olfaction. We generated a 3D atlas at several stages which are representative of the reorganization process. This will be a useful tool for future studies of development and function.