A new safety index based on intrapulse monitoring of ultra-harmonic cavitation during ultrasound-induced blood-brain barrier opening procedures.

Ultrasound-induced blood-brain barrier (BBB) opening using microbubbles is a promising technique for local delivery of therapeutic molecules into the brain. The real-time control of the ultrasound dose delivered through the skull is necessary as the range of pressure for efficient and safe BBB opening is very narrow. Passive cavitation detection (PCD) is a method proposed to monitor the microbubble activity during ultrasound exposure. However, there is still no consensus on a reliable safety indicator able to predict potential damage in the brain. Current approaches for the control of the beam intensity based on PCD employ a full-pulse analysis and may suffer from a lack of sensitivity and poor reaction time. To overcome these limitations, we propose an intra-pulse analysis to monitor the evolution of the frequency content during ultrasound bursts. We hypothesized that the destabilization of microbubbles exposed to a critical level of ultrasound would result in the instantaneous generation of subharmonic and ultra-harmonic components. This specific signature was exploited to define a new sensitive indicator of the safety of the ultrasound protocol. The approach was validated in vivo in rats and non-human primates using a retrospective analysis. Our results demonstrate that intra-pulse monitoring was able to exhibit a sudden appearance of ultra-harmonics during the ultrasound excitation pulse. The repeated detection of such a signature within the excitation pulse was highly correlated with the occurrence of side effects such as hemorrhage and edema. Keeping the acoustic pressure at levels where no such sign of microbubble destabilization occurred resulted in safe BBB openings, as shown by MR images and gross pathology. This new indicator should be more sensitive than conventional full-pulse analysis and can be used to distinguish between potentially harmful and safe ultrasound conditions in the brain with very short reaction time.

Cerebrospinal fluid leakage after posterior fossa surgery may impair brain metabolite clearance.

The discovery of the important role of cerebrospinal fluid (CSF) drainage of cerebral metabolite waste, known as the glymphatic system, has changed our view of brain waste clearance. We recently performed experiments to evaluate the glymphatic system in non-human primates (NHP). Here, we report the case of an NHP with iatrogenic CSF leakage. In this animal, solute transport through the brain, assessed by gadolinium injection in the CSF, was severely impaired by iatrogenic pseudomeningocele. This observation raises an important question: does brain surgery, and particularly posterior fossa surgery, lead to chronic impairment of parenchymal CSF circulation and solute transport?

Optogenetic Tractography for anatomo-functional characterization of cortico-subcortical neural circuits in non-human primates.

Dissecting neural circuitry in non-human primates (NHP) is crucial to identify potential neuromodulation anatomical targets for the treatment of pharmacoresistant neuropsychiatric diseases by electrical neuromodulation. How targets of deep brain stimulation (DBS) and cortical targets of transcranial magnetic stimulation (TMS) compare and might complement one another is an important question. Combining optogenetics and tractography may enable anatomo-functional characterization of large brain cortico-subcortical neural pathways. For the proof-of-concept this approach was used in the NHP brain to characterize the motor cortico-subthalamic pathway (m_CSP) which might be involved in DBS action mechanism in Parkinson's disease (PD). Rabies-G-pseudotyped and Rabies-G-VSVg-pseudotyped EIAV lentiviral vectors encoding the opsin ChR2 gene were stereotaxically injected into the subthalamic nucleus (STN) and were retrogradely transported to the layer of the motor cortex projecting to STN. A precise anatomical mapping of this pathway was then performed using histology-guided high angular resolution MRI tractography guiding accurately cortical photostimulation of m_CSP origins. Photoexcitation of m_CSP axon terminals or m_CSP cortical origins modified the spikes distribution for photosensitive STN neurons firing rate in non-equivalent ways. Optogenetic tractography might help design preclinical neuromodulation studies in NHP models of neuropsychiatric disease choosing the most appropriate target for the tested hypothesis.

Dramatic increase in mud distribution across a large sub-tropical embayment, Moreton Bay, Australia.

Major flood events can dramatically alter the coastal sediment environment. This study established the current sediment distribution in a large sub-tropical embayment, Moreton Bay, Australia, and examined the effect of three recent floods on modifying this distribution. In 2015, surface sediment samples were collected from 223 sites across the study area and analysed for particle size distribution with the resultant sediment distribution mapped. In addition, sampling of flood waters during two major events in 2011 and 2013 was undertaken and particle size distribution of suspended sediment was determined. Data was compared to the result of an earlier large-scale survey completed in 1970, with three large flood events occurring between the two surveys. The sediment environment has undergone a dramatic change with muddy sediments now covering an estimated area of over 860km2, more the double the area found in 1970. Mud is now the dominant sediment type within Moreton Bay.

Posttransplant Lymphoproliferative Disorders in Neuronal Xenotransplanted Macaques.

Posttransplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of lymphoid proliferations that occur in the setting of depressed T-cell function due to immunosuppressive therapy used following solid organ transplantation, hematopoietic stem cell transplantation, and also xenotransplantation. In the present study, 28 immunosuppressed parkinsonian Macaca fascicularis were intracerebrally injected with wild-type or CTLA4-Ig transgenic porcine xenografts to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Nine of 28 (32%) immunosuppressed primates developed masses compatible with PTLD, located mainly in the gastrointestinal tract and/or nasal cavity. The masses were classified as monomorphic PTLD according to the World Health Organization classification. Immunohistochemistry and polymerase chain reaction (PCR) analyses revealed that the PTLDs were associated with macaca lymphocryptovirus as confirmed by double-labeling immunohistochemistry for CD20 and Epstein-Barr nuclear antigen 2 (EBNA-2), where the viral protein was located within the CD20+ neoplastic B cells. In sera from 3 distinct phases of the experimental life of the primates, testing by quantitative PCR revealed a progression of the viral load that paralleled the PTLD progression and no evidence of zoonotic transmission of porcine lymphotropic herpesvirus through xenoneuronal grafts. These data suggest that monitoring the variation of macaca lymphocryptovirus DNA in primates could be used as a possible early diagnostic tool for PTLD progression, allowing preemptive treatment such as immunosuppression therapy reduction.

Cell Therapy for Parkinson's Disease: A Translational Approach to Assess the Role of Local and Systemic Immunosuppression.

Neural transplantation is a promising therapeutic approach for neurodegenerative diseases; however, many patients receiving intracerebral fetal allografts exhibit signs of immunization to donor antigens that could compromise the graft. In this context, we intracerebrally transplanted mesencephalic pig xenografts into primates to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Parkinsonian primates received WT or CTLA4-Ig transgenic porcine xenografts and different durations of peripheral immunosuppression to test whether systemic plus graft-mediated local immunosuppression might avoid rejection. A striking recovery of spontaneous locomotion was observed in primates receiving systemic plus local immunosuppression for 6 mo. Recovery was associated with restoration of dopaminergic activity detected both by positron emission tomography imaging and histological examination. Local infiltration by T cells and CD80/86+ microglial cells expressing indoleamine 2,3-dioxigenase were observed only in CTLA4-Ig recipients. Results suggest that in this primate neurotransplantation model, peripheral immunosuppression is indispensable to achieve the long-term survival of porcine neuronal xenografts that is required to study the beneficial immunomodulatory effect of local blockade of T cell costimulation.

[18F]DPA-714 PET imaging of translocator protein TSPO (18 kDa) in the normal and excitotoxically-lesioned nonhuman primate brain.

PURPOSE: We aimed to characterize pharmacologically the TSPO- radioligand [(18)F]DPA-714 in the brain of healthy cynomolgus monkeys and evaluate the cellular origin of its binding in a model of neurodegeneration induced by intrastriatal injection of quinolinic acid (QA). METHODS: [(18)F]DPA-714 PET images were acquired before and at 2, 7, 14, 21, 49, 70, 91 days after putaminal lesioning. Blocking and displacement studies were carried out (PK11195). Different modelling approaches estimated rate constants and V T (total distribution volume) which was used to measure longitudinal changes in the lesioned putamen. Sections for immunohistochemical labelling were prepared at the same time-points to evaluate correlations between in vivo [(18)F]DPA-714 binding and microglial/astrocytic activation. RESULTS: [(18)F]DPA-714 showed a widespread distribution with a higher signal in the thalamus and occipital cortex and lower binding in the cerebellum. TSPO was expressed throughout the whole brain and about 73 % of [(18)F]DPA-714 binding was specific for TSPO in vivo. The one-tissue compartment model (1-TCM) provided good and reproducible estimates of V T and rate constants, and V T values from the 1-TCM and the Logan approach were highly correlated (r (2) = 0.85). QA lesioning induced an increase in V T, which was +17 %, +54 %, +157 % and +39 % higher than baseline on days 7, 14, 21 and 91 after QA injection, respectively. Immunohistochemistry revealed an early microglial and a delayed astrocytic activation after QA injection. [(18)F]DPA-714 binding matched TSPO immunopositive areas and showed a stronger colocalization with CD68 microglia than with GFAP-activated astrocytes. CONCLUSION: [(18)F]DPA-714 binds to TSPO with high specificity in the primate brain under normal conditions and in the QA model. This tracer provides a sensitive tool for assessing neuroinflammation in the human brain.

Designing primate models to assess the prodromal phase of Huntington's disease.

Huntington's disease (HD) is an inherited autosomal-dominant neurodegenerative disorder characterized by frontal-type cognitive deficits, involuntary choreiform movements and progressive neuronal degeneration, primarily affecting the caudate-putamen complex. There is currently no effective therapy for this disorder. Numerous efforts are directed towards the search and validation of new therapies to prevent or slow down disease progression. To this end, different animal models, including in nonhuman primates, have been developed to mimic the early phase of neuronal dysfunction that precedes degeneration in this pathology. The present manuscript provides a critical evaluation of existing and currently developed primate models of Huntington's disease. Their pertinence and predictability for the evaluation of innovative therapeutic strategies are also discussed.

Patterns of allelic loss at the BRCA1 locus in Arabic women with breast cancer.

Loss of heterozygosity (LOH) of BRCA1, a tumor suppressor gene, is one mechanism of genetic inactivation in both sporadic and familial forms of breast cancer. Studies reported in breast cancers from women of Northern European descent have shown LOH in 30-50% of sporadic tumors. Microsatellite instability (MSI) has served as evidence for involvement of DNA repair genes. This study investigates the extent of allelic imbalance at the BRCA1 region in Arabic women with breast cancer. Paired normal and tumor tissue were available for DNA analysis in 13 cases. Results using fluorescent tagged primers to microsatellite markers D17S1323, D17S1325 and D17S855 intragenic to BRCA1 were analyzed using an ABI 310 DNA sequencer. As compared to normal DNA, MSI and LOH were recognized as a gain and a loss, respectively, of one signal in one allele in the tumor DNA. Microsatellite analyses showed 12 of 13 (92%) cases with LOH or MSI or both. Three cases demonstrated LOH alone, 3 cases with MSI alone. Six cases indicated both LOH and MSI; 2 cases with either LOH or MSI in separate markers. The combined finding of LOH and MSI in the same marker was detected only with D17S1325 in 4/6 cases. The proportion of aberrant findings of the BRCA1 locus in breast cancer appears to be higher in Arabic women than in other populations studied to date.

Nitric oxide production and mitochondrial dysfunction during rat thymocyte apoptosis.

Production of nitric oxide (NO) by mitochondrial membranes as methemoglobin formation sensitive to N(G)-methyl-l-arginine inhibition and mitochondrial O(2) consumption in metabolic states 3 and 4 and the respiratory control (state 3/state 4) were measured at early stages of rat thymocyte apoptosis. Programmed cell death was induced by addition of methylprednisolone and etoposide to thymocyte suspensions. Increased NO production by mitochondrial membranes was observed after 30 min of methylprednisolone and etoposide addition and was accompanied by mitochondrial respiratory impairment as an early phenomenon in apoptotic thymocytes. The respiratory control in isolated mitochondria from untreated thymocytes was 4.2 +/- 0.2 and decreased to 3.1 +/- 0.2 and 1.9 +/- 0.3 after 1 h of methylprednisolone and etoposide treatment, respectively. The low mitochondrial respiratory control was accompanied by a marked decrease in GSH and cytochrome c content. Moreover, an inhibitory effect in the amount of apoptosis due to thymocyte pretreatment with N(G)-methyl-l-arginine and N(omega)-nitro-(l)-arginine (l-NNA), indicate that nitric oxide production is closely involved in the signaling of rat thymocyte apoptosis.

A Rehnquistean bed: the abortion issue revisited.

Individuals as members of societies are subject to externally imposed norms of behavior (laws). When societal control and regulation adversely impact upon individual autonomy, conflict is frequently the end product. Such issues surround the rights of privacy vis-a-vis the abortion issue. The Supreme Court addressed this issue in the 1988-1989 term. This article critically examines the court's decision and raises questions of individual and professional import.

PIP: Certain types of laws grant the state powers or rights over a person if that person is considered incapable of autonomy. In the past this has included mentally and physically disabled people as well as abandoned children. In Roe v. Wade the state granted itself the right to care for that unborn fetuses that were viable. Women were allowed to have abortions before viability or "quickening", usually the after the 1st trimester. Roe set up a balance between a woman's right to privacy and the state's interest in potential life and uses viability as the fulcrum. However the trimester approach using a test of viability is a self destructive argument. As medical technology progresses, viability moves closer to conception and increasingly restricts a woman's right to abort. The Webster decision has significantly narrowed the scope of Roe by allowing the Missouri law to stand that lets the state legislate viability instead of using the trimester approach of Roe. The fall-out from Webster is that the states no longer have any judicial guidelines for determining viability. This new situation leaves many fundamental question unanswered is the state obligated to fund the development of the fetus after viability? After birth? Will it ultimately become illegal to decide not to gestate if viability occurs at conception? Will the state mandate a mother's responsibility to the fetus after a complete extra-uterine gestation? Should the father pay to raise the child? If the state's rights continue to grow as Webster allows, the where does a woman's right to privacy begin and the states interest in potential life end?