The variable influence of dispersant on degradation of oil hydrocarbons in subarctic deep-sea sediments at low temperatures (0-5 °C)

The microbial degradation of petroleum hydrocarbons at low temperatures was investigated in subarctic deep-sea sediments in th e Faroe Shetland Channel (FSC). The effect of the marine oil dispersant, Superdispersant 25 on hydrocarbon degradation was also examined. Sediments collected at 500 and 1000 m depth were spiked with a model oil containing 20 hydrocarbons and incubated at ambient temperature (5 and 0 °C, respectively) with and without marine dispersant. Treatment of sediments with hydrocarbons resulted in the enrichment of Gammaproteobacteria, and specifically the genera Pseudoalteromonas, Pseudomonas, Halomonas, and Cobetia. Hydrocarbon degradation was faster at 5 °C (500 m) with 65-89% of each component degraded after 50 days compared to 0-47% degradation at 0 °C (1000 m), where the aromatic hydrocarbons fluoranthene, anthracene, and Dibenzothiophene showed no degradation. Dispersant significantly increased the rate of degradation at 1000 m, but had no effect at 500 m. There was no statistically significant effect of Superdispersant 25 on the bacterial community structure at either station. These results show that the indigenous bacterial community in the FSC has the capacity to mitigate some of the effects of a potential oil spill, however, the effect of dispersant is ambiguous and further research is needed to understand the implications of its use

Role of whole bone marrow, whole bone marrow cultured cells, and mesenchymal stem cells in chronic wound healing

INTRODUCTION: Recent evidence has shown that bone marrow cells play critical roles during the inflammatory, proliferative and remodeling phases of cutaneous wound healing. Among the bone marrow cells delivered to wounds are stem cells, which can differentiate into multiple tissue-forming cell lineages to effect, healing. Gaining insight into which lineages are most important in accelerating wound healing would be quite valuable in designing therapeutic approaches for difficult to heal wounds. METHODS: In this report we compared the effect of different bone marrow preparations on established in vitro wound healing assays. The preparations examined were whole bone marrow (WBM), whole bone marrow (long term initiating/hematopoietic based) cultured cells (BMC), and bone marrow derived mesenchymal stem cells (BM-MSC). We also applied these bone marrow preparations in two murine models of radiation induced delayed wound healing to determine which had a greater effect on healing. RESULTS: Angiogenesis assays demonstrated that tube formation was stimulated by both WBM and BMC, with WBM having the greatest effect. Scratch wound assays showed higher fibroblast migration at 24, 48, and 72 hours in presence of WBM as compared to BM-MSC. WBM also appeared to stimulate a greater healing response than BMC and BM-MSC in a radiation induced delayed wound healing animal model. CONCLUSIONS: These studies promise to help elucidate the role of stem cells during repair of chronic wounds and reveal which cells present in bone marrow might contribute most to the wound healing process

Dysmyelination in Transgenic Mice Resulting From Expression of Class-I Histocompatibility Molecules in Oligodendrocytes

MAJOR histocompatibility complex (MHC) molecules are not normally expressed in the central nervous system (CNS) 1-3. However, aberrant expression has been observed in multiple sclerosis lesions and could contribute to the destruction of myelin or the myelinating cells known as oligodendrocytes 4,5. The mechanism of cell damage associated with aberrant MHC molecule expression is unclear: for example, overexpression of class I (ref. 6) and class II (refs 7, 8) MHC molecules in pancreatic beta-cells in transgenic mice leads to nonimmune destruction of the cells and insulin-dependent diabetes mellitus. We have generated transgenic mice that express class I H-2K(b) MHC molecules, under the control of the myelin basic protein promoter, specifically in oligodendrocytes. Homozygous transgenic mice have a shivering phenotype, develop tonic seizures and die at 15-22 days. This phenotype, which we term 'wonky', is due to hypomyelination in the CNS, and not to involvement of the immune system. The primary defect appears to be a shortage of myelinating oligodendrocytes resulting from overexpression of the class I MHC molecules

Fear of the Unknown: Uncertain Anticipation Reveals Amygdala Alterations in Childhood Anxiety Disorders

Children with anxiety disorders (ADs) experience persistent fear and worries that are highly debilitating, conferring risk for lifelong psychopathology. Anticipatory anxiety is a core clinical feature of childhood ADs, often leading to avoidance of uncertain and novel situations. Extensive studies in non-human animals implicate amygdala dysfunction as a critical substrate for early life anxiety. To test specific amygdala-focused hypotheses in preadolescent children with ADs, we used fMRI to characterize amygdala activation during uncertain anticipation and in response to unexpected stimuli. Forty preadolescent (age 8–12 years) children, 20 unmedicated AD patients and 20 matched controls completed an anticipation task during an fMRI scan. In the task, symbolic cues preceded fear or neutral faces, such that ‘certain ’ cues always predicted the presentation of fear or neutral faces, whereas ‘uncertain ’ cues were equally likely to be followed by fear or neutral faces. Both AD children and controls showed robust amygdala response to faces. In response to the uncertain cues, AD children had increased amygdala activation relative to controls. Moreover, in the AD children, faces preceded by an ‘uncertain’ cue elicited increased amygdala activation, as compared with the same faces following a ‘certain ’ cue. Children with ADs experience distress both in anticipation of and during novel and surprising events. Our findings suggest that increased amygdala activation may hav