Successful transnasal delivery of stem cells in a rat model of perinatal hypoxic-ischemic brain injury

OBJECTIVE: New routes for cell transplantation into the brain need to be explored as intracerebral or intrathecal applications have a high risk to cause damage to the central nervous system. It has been hypothesized that transnasally administrated cells bypass the blood-brain barrier and migrate along the olfactory neural route into the brain and cerebrospinal fluid. Our goal is to confirm this hypothesis by transnasally administrating Wharton’s Jelly mesenchymal stem cells (WJ-MSC) and neural progenitor cells (NPC) to perinatal rats in a model of hypoxic-ischemic brain injury. STUDY DESIGN: Four-day-old Wistar rat pups, previously brain-damaged by combined hypoxic-ischemic and inflammatory insult, either received WJ-MSC or green fluorescent protein-expressing NPC: The heads of the rat pups were immobilized and 3 ml drops containing the cells (50’000 cells/ml) were placed on one nostril allowing it to be snorted. This procedure was repeated twice, alternating right to left nostril with an interval of one minute between administrations. The rat pups received a total of 600’000 cells. Animals were sacrificed 24h, 48h or 7 days after the application of the cells. Fixed brains were collected, embedded in paraffin and sectioned. RESULTS: Transplanted cells were found in the layers of the olfactory bulb (OB), the cerebral cortex, thalamus and the hippocampus. The amount of cells was highest in the OB. Animals treated with transnasally delivered stem cells showed significantly decreased gliosis compared to untreated animals. CONCLUSION: Our data show that transnasal delivery of WJ-MSC and NPC to the newborn brain after perinatal brain damage is successful. The cells not only migrate the brain, but also decrease scar formation and improve neurogenesis. Therefore, the non-invasive intranasal delivery of stem cells to the brain may be the preferred method for stem cell treatment of perinatal brain damage and should be preferred in future clinical trials.

Racking the brain: detection of cerebral edema on postmortem computed tomography compared with forensic autopsy

PURPOSE The purpose of this study was to compare postmortem computed tomography with forensic autopsy regarding their diagnostic reliability of differentiating between pre-existing cerebral edema and physiological postmortem brain swelling. MATERIALS AND METHODS The study collective included a total of 109 cases (n=109/200, 83 male, 26 female, mean age: 53.2 years) and were retrospectively evaluated for the following parameters (as related to the distinct age groups and causes of death): tonsillar herniation, the width of the outer and inner cerebrospinal fluid spaces and the radiodensity measurements (in Hounsfield Units) of the gray and white matter. The results were compared with the findings of subsequent autopsies as the gold standard for diagnosing cerebral edema. p-Values <0.05 were considered statistically significant. RESULTS Cerebellar edema (despite normal postmortem swelling) can be reliably assessed using postmortem computed tomography and is indicated by narrowed temporal horns and symmetrical herniation of the cerebellar tonsils (p<0.001). There was a significant difference (p<0.001) between intoxication (or asphyxia) and all other causes of death; the former causes demonstrated higher deviations of the attenuation between white and gray matter (>20 Hounsfield Units), and the gray to white matter ratio was >1.58 when leukoencephalopathy was excluded. CONCLUSIONS Despite normal postmortem changes, generalized brain edema can be differentiated on postmortem computed tomography, and white and gray matter Hounsfield measurements help to determine the cause of death in cases of intoxication or asphyxia. Racking the brain about feasible applications for a precise and reliable brain diagnostic forensic radiology method has just begun.

Brain barriers: Crosstalk between complex tight junctions and adherens junctions

Unique intercellular junctional complexes between the central nervous system (CNS) microvascular endothelial cells and the choroid plexus epithelial cells form the endothelial blood-brain barrier (BBB) and the epithelial blood-cerebrospinal fluid barrier (BCSFB), respectively. These barriers inhibit paracellular diffusion, thereby protecting the CNS from fluctuations in the blood. Studies of brain barrier integrity during development, normal physiology, and disease have focused on BBB and BCSFB tight junctions but not the corresponding endothelial and epithelial adherens junctions. The crosstalk between adherens junctions and tight junctions in maintaining barrier integrity is an understudied area that may represent a promising target for influencing brain barrier function.

Endoscopic Biopsy for Intra- and Paraventricular Tumors: Rates of Complications, Mortality, and Tumor Cell Dissemination

Background and Study Aim Intra- and paraventricular tumors are frequently associated with cerebrospinal fluid (CSF) pathway obstruction. Thus the aim of an endoscopic approach is to restore patency of the CSF pathways and to obtain a tumor biopsy. Because endoscopic tumor biopsy may increase tumor cell dissemination, this study sought to evaluate this risk. Patients, Materials, and Methods Forty-four patients who underwent endoscopic biopsies for ventricular or paraventricular tumors between 1993 and 2011 were included in the study. Charts and images were reviewed retrospectively to evaluate rates of adverse events, mortality, and tumor cell dissemination. Adverse events, mortality, and tumor cell dissemination were evaluated. Results Postoperative clinical condition improved in 63.0% of patients, remained stable in 30.4%, and worsened in 6.6%. One patient (2.2%) had a postoperative thalamic stroke leading to hemiparesis and hemineglect. No procedure-related deaths occurred. Postoperative tumor cell dissemination was observed in 14.3% of patients available for follow-up. Conclusions For patients presenting with occlusive hydrocephalus due to tumors in or adjacent to the ventricular system, endoscopic CSF diversion is the procedure of first choice. Tumor biopsy in the current study did not affect safety or efficacy.

Streptococcus pneumoniae capsule determines disease severity in experimental pneumococcal meningitis.

Streptococcus pneumoniaebacteria can be characterized into over 90 serotypes according to the composition of their polysaccharide capsules. Some serotypes are common in nasopharyngeal carriage whereas others are associated with invasive disease, but when carriage serotypes do invade disease is often particularly severe. It is unknown whether disease severity is due directly to the capsule type or to other virulence factors. Here, we used a clinical pneumococcal isolate and its capsule-switch mutants to determine the effect of capsule, in isolation from the genetic background, on severity of meningitis in an infant rat model. We found that possession of a capsule was essential for causing meningitis. Serotype 6B caused significantly more mortality than 7F and this correlated with increased capsule thickness in the cerebrospinal fluid (CSF), a stronger inflammatory cytokine response in the CSF and ultimately more cortical brain damage. We conclude that capsule type has a direct effect on meningitis severity. This is an important consideration in the current era of vaccination targeting a subset of capsule types that causes serotype replacement.

Diversity in T cell costimulation by alpha4beta1 integrin

T cell activation requires antigen-specific T cell receptor signals that spatially and temporally coincide with a second costimulatory signal. CD28 and α4β1 integrin both function as T cell costimulators, but their individual mechanisms remain elusive. By directly comparing CD3-dependent functions and signaling pathways employed by these two costimulatory receptors, aspects of their individual signaling mechanisms are explored. We determined that CD28 and α4β1 integrins both use Src-family kinase Lck and MAPK Erk, but to different extents and functional ends. After identifying functional differences between CD28 and integrin costimulatory pathways, the focus of the study turned to integrin signaling in naïve and memory T cell subsets. CD45RO T cells are fully co-activated by natural β1 integrin ligands fibronectin (FN) and VCAM-1, β1 monoclonal antibody 33B6, as well as α4β1 monoclonal antibody 19H8 which binds a combinatorial epitope of the α4β1 heterodimer. While CD28 fully costimulates CD45RA T cells, the degree of activation from integrin ligands varies. FN costimulates CD3-dependent proliferation, IL-2 secretion, and early activation markers CD25 and CD69. However, β1 antibody 33B6, which binds to the same T cell integrins (α4β1 and α5β1) as natural ligand FN, failed to costimulate proliferation or IL-2 in the CD45RA subset, but retained the ability to regulate CD25 and CD69. Unique aspects of 19H8 signaling involve early Erk activation and IL-2 independent proliferation. Signaling defects through 33B6 ligation correlates with poor adhesion under fluid flow conditions, suggesting a cytoskeletal basis for signaling. All together, these data provide evidence for a mechanism of α4β1 integrin signaling and describe functional differences between naïve and memory T cells. ^

Chemistry of minerals from amphibole-chlorite veins of ODP Site 209-1270

We examined small-scale shear zones in drillcore samples of abyssal peridotites from the Mid-Atlantic Ridge. These shear zones are associated with veins consisting of chlorite + actinolite/tremolite assemblages, with accessory phases zircon and apatite, and they are interpreted as altered plagiogranite melt impregnations, which originate from hydrous partial melting of gabbroic intrusion in an oceanic detachment fault. Ti-in-zircon thermometry yields temperatures around 820°C for the crystallization of the evolved melt. Reaction path modeling indicates that the alteration assemblage includes serpentine of the adjacent altered peridotites. Based on the model results, we propose that formation of chlorite occurred at higher temperatures than serpentinization, thus leading to strain localization around former plagiogranites during alteration. The detachment fault represents a major pathway for fluids through the oceanic crust, as evidenced by extremely low d18O of altered plagiogranite veins (+3.0-4.2 per mil) and adjacent serpentinites (+ 2.6-3.7 per mil). The uniform oxygen isotope data indicate that fluid flow in the detachment fault system affected veins and adjacent host serpentinites likewise.

Geophysical logging on sediment core and hole CRP-3 from the Ross Sea, Antarctica

Cape Roberts drillhole CRP-3 in the northern part of McMurdo Sound (Ross Sea, Antarctica) targeted the western margin of the Victoria Land basin to investigate Neogene to Palaeogene climatic and tectonic history by obtaining continuous core and downhole logs (Cape Roberts Science Team, 2000). The CRP-3 drillhole extended to 939.42 mbsf (meters below seafloor) at a water depth of 297 m. The first downhole measurements after drilling were the temperature and salinity logs. Both were measured at the beginning and at the end of each of the three logging phases. Although an equilibrium temperature state may not have been fully reached after drilling, the temperature and salinity profiles seem to be scarcely disturbed. The average overall temperature gradient calculated from all temperature measurements is 28.5 K/km; remarkably lower than the temperature gradients found in other boreholes in the western Ross See and the Transantarctic Mountains. Anomalies in the salinity profiles at the beginning of each logging phase were no longer present at the end of the corresponding logging phase. This pattern indicates that drilling mud invaded the formation during drilling operations and flowed back into the borehole after drilling ceased. Thus, zones of temperature and salinity anomalies identify permeable zones in the formation and may be pathways for fluid flow. Radiogenic heat production, calculated from the radionuclide contents, is relatively low, with average values between 0.5 and 1.0 pW/m3. The highest values (up to 2 µW/m3) were obtained for the lower part of the Beacon Sandstone below 855 mbsf. The heat flow component due to radiogenic heat production integrated over the entire borehole is 0.7 mW/m2. Thermal conductivities range from 1.3 to 3 W/mK with an average value of 2.1 W/mK over the Tertiary section. Together with the average temperature gradient of 28.5 K/km this yields an average heat flow value of 60 mW/m2.

(Table 1) Summary of sampling points described and main petrographic, morphological and geochemical characteristics

Targeted sampling on the Dolgovskoy Mound (northern Shatsky Ridge) revealed the presence of spectacular laterally extensive and differently shaped authigenic carbonates. The sampling stations were selected based on sidescan sonar and profiler images that show patchy backscatter and irregular and discontinuous reflections in the near subsurface. The interpretation of acoustic data from the top part of the mound supports the seafloor observations and the sampling that revealed the presence of a complex subsurface plumbing system characterized by carbonates and gas. The crusts sampled consist of carbonate cemented layered hemipelagic sedimentary Unit 1 associated with several centimetres thick microbial mats. Three different carbonate morphologies were observed: (a) tabular slabs, (b) subsurface cavernous carbonates consisting of void chambers up to 20 cm**3 in size and (c) chimney and tubular conduits vertically oriented or forming a subhorizontal network in the subsurface. The methanogenic origin of the carbonates is established based on visual observations of fluids seepage structures, 13C depletion of the carbonates (d13C varying between -36.7 per mil and -27.4 per mil), and by thin carbonate layers present within the thick microbial mats. Laboratory experiments with a Hele-Shaw cell were conducted in order to simulate the gas seepage through contrasting grain size media present on the seafloor. Combined petrography, visual observations and sandbox simulations allowed a characterization of the dynamics and the structures of the plumbing system in the near subsurface. Based on sample observations and the experiments, three observed morphologies of authigenic carbonates are interpreted, respectively, as (a) Darcian porous flow through the finely laminated clayey/coccolith-rich layers, (b) gas accumulation chambers at sites where significant fluid escape was impeded by thicker clayey layers forming the laminated Unit1 and (c) focussed vertical fluid venting and subhorizontal migration of overpressured fluids released from (b). The Hele-Shaw cell experiments represent a promising tool for investigating shallow fluid flow pathways in marine systems.

Tab. 1: Trace-element concentrations in ore samples collected from mercury mines and deposits in southwestern Alaska

A belt of small but numerous mercury deposits extends for about 500 km in the Kuskokwim River region of southwestern Alaska. The southwestern Alaska mercury belt is part of widespread mercury deposits of the circum Pacific region that are similar to other mercury deposits throughout the world because they are epithermal with formation temperatures of about 200 °C, the ore is dominantly cinnabar with Hg-Sb-As±Au geochemistry, and mineralized forms include vein, vein breccias, stockworks, replacements, and disseminations. The southwestern Alaska mercury belt has produced about 1400 t of mercury, which is small on an international scale. However, additional mercury deposits are likely to be discovered because the terrain is topographically low with significant vegetation cover. Anomalous concentrations of gold in cinnabar ore suggest that gold deposits are possible in higher temperature environments below some of the Alaska mercury deposits. We correlate mineralization of the southwestern Alaska mercury deposits with Late Cretaceous and early Tertiary igneous activity. Our 40Ar/39Ar ages of 70 ±3 Ma from hydrothermal sericites in the mercury deposits indicate a temporal association of igneous activity and mineralization. Furthermore, we suggest that our geological ancl geochemical data from the mercury deposits indicate that ore fluids were generated primarily in surrounding sedimentary wall rocks when they were cut by Late Cretaceous and early Tertiary intrusions. In our ore genesis model, igneous activity provided the heat to initiate dehydration reactions and expel fluids from hydrous minerals and formational waters in the surrounding sedimentary wall rocks, causing thermal convection and hydrothermal fluid flow through permeable rocks and along fractures and faults. Our isotopic data from sulfide and alteration minerals of the mercury deposits indicate that ore fluids were derived from multiple sources, with most ore fluids originating from the sedimentary wall rocks.

Strike-slip faults mediate the rise of crustal-derived fluids and mud volcanism in the deep sea

We report on newly discovered mud volcanoes located at about 4500 m water depth 90 km west of the deformation front of the accretionary wedge of the Gulf of Cadiz, and thus outside of their typical geotectonic environment. Seismic data suggest that fluid flow is mediated by a >400-km-long strike-slip fault marking the transcurrent plate boundary between Africa and Eurasia. Geochemical data (Cl, B, Sr, 87Sr/86Sr, Delta18O, DeltaD) reveal that fluids originate in oceanic crust older than 140 Ma. On their rise to the surface, these fluids receive strong geochemical signals from recrystallization of Upper Jurassic carbonates and clay-mineral dehydration in younger terrigeneous units. At present, reports of mud volcanoes in similar deep-sea settings are rare, but given that the large area of transform-type plate boundaries has been barely investigated, such pathways of fluid discharge may provide an important, yet unappreciated link between the deeply buried oceanic crust and the deep ocean.

Granulometry, mineralogy and geochemistry of sediments from ODP Hole 169-1037B and Site 169-1038

Central Hill is in the northern part of the Escanaba Trough, which is a sediment-filled rift of southern Gorda Ridge. Central Hill is oriented north-south and is associated with extensive sulfide deposits. Hydrothermal alteration of sediment from Site 1038 was studied through analyses of mineralogy and the chemistry and oxygen isotopic compositions of one nearly pure clay sample. In addition, Site 1037 was drilled to establish the character of the unaltered sedimentary sequence away from the hydrothermal centers of the Northern Escanaba Trough Study Area (NESCA). Mineralogy of the clay-size fraction of turbiditic and hemipelagic sediments of Hole 1037B are predominantly quartz, feldspar, pyroxene, illite, chlorite, and smectite, representing continental-derived material. Cores from Hole 1038I, located within the area of Central Hill but away from known active vent areas, recovered minor amounts of chlorite/smectite mixed-layer clay in the fine fraction, indicating a low-temperature hydrothermal alteration. The 137.4-m-thick sediment section of Hole 1038G is located in an area of low-temperature venting. The uppermost sample is classified as chlorite/smectite mixed layer, which is underlain by chlorite as the dominant mineral. The lowermost deposits of Hole 1038G are also characterized by chlorite/smectite mixed-layer clay. In comparison to Hole 1038I, the mineralogic sequence of Hole 1038G reflects increased chloritization. Intensely altered sediment is almost completely replaced by hydrothermal chlorite in subsurface sediments of Hole 1038H. Alteration to chlorite is characterized by depletion in Na, K, Ti, Ca, Sr, Cs, and Tl and enrichment in Ba. Further, Eu depletion reflects a high-temperature plagioclase alteration. A chlorite 18O value of 2.6 indicates formation at a temperature of ~190°C. It is concluded that the authigenic chlorite in Hole 1038H formed by an active high-temperature fluid flow in the shallow subsurface.

U/Th systematics of authigenic carbonates and d18O records from Hydrate Ridge, off the coast of Oregon, USA

Uranium (U) concentrations and activity ratios (d234U) of authigenic carbonates are sensitive recorders of different fluid compositions at submarine seeps of hydrocarbon-rich fluids ("cold seeps") at Hydrate Ridge, off the coast of Oregon, USA. The low U concentrations (mean: 1.3 ± 0.4 µg/g) and high 234U values (165-317 per mil) of gas hydrate carbonates reflect the influence of sedimentary pore water indicating that these carbonates were formed under reducing conditions below or at the seafloor. Their 230Th/234U ages span a time interval from 0.8 to 6.4 ka and cluster around 1.2 and 4.7 ka. In contrast, chemoherm carbonates precipitate from marine bottom water marked by relatively high U concentrations (mean: 5.2 ± 0.8 µg/g) and a mean d234U ratio of 166 ± 3 per mil. Their U isotopes reflect the d234U ratios of the bottom water being enriched in 234U relative to normal seawater. Simple mass balance calculations based on U concentrations and their corresponding d234U ratios reveal a contribution of about 11% of sedimentary pore water to the bottom water. From the U pore water flux and the reconstructed U pore water concentration a mean flow rate of about 147 ± 68 cm/a can be estimated. 230Th/234U ages of chemoherm carbonates range from 7.3 to 267.6 ka. 230Th/234U ages of two chemoherms (Alvin and SE-Knoll chemoherm) correspond to time intervals of low sealevel stands in marine isotope stages (MIS) 2, 4, 5, 6, 7 and 8. This observation indicates that fluid flow at cold seep sites sensitively reflects pressure changes of the hydraulic head in the sediments. The d18OPDB ratios of the chemoherm carbonates support the hypothesis of precipitation during glacial times. Deviations of the chemoherm d18O values from the marine d18O record can be interpreted as to reflect temporally and spatially varying bottom water and/or vent fluid temperatures during carbonate precipitation between 2.6 and 8.6°C.