Organic matter composition in the sediment of three Brazilian coastal lagoons: district of Macaé, Rio de Janeiro (Brazil)

Freshwater lagoons comprise important coastal ecosystems and natural buffers between urbanized land areas and open ocean in the Rio de Janeiro State, Brazil. Studies of sediment and water chemistry, zooplankton and bacterial communities to assess the extent of anthropogenic disturbance are available. Here we contribute with an organic-geochemical approach supplemented by some microbiological aspects to complete the characterization of these lagoonal ecosystems. Bulk organic matter and extractable lipids (aliphatic hydrocarbons, alcohols and fatty acids, sterols) were investigated from two locations per lagoon: at the seaward site and landward ends - and at two depth intervals (0-3 and 3-6 cm) per site. Urbanized Imboacica Lagoon received increased anthropogenic input over the most recent years represented by the topmost 3 cm of sediment, whereas deeper sediment layers are less affected by human influence. Eutrophication or nutrient availability favored enhanced algal/cyanobacterial growth. In remote Cabiúnas and Comprida Lagoons pristine conditions are preserved. Organic matter from vascular plants dominates (chain length of free lipids up to C36), which is exceptionally well preserved by acidic lagoonal waters. Differentiation between landward and seaward sites in these two lagoons is less well established due to much smaller surface/volume to catchment ratios. No anthropogenic influences are yet detectable in sediments of Cabiúnas and Comprida Lagoons.     

Cat area 17. II. Response properties of infragranular layer neurons in the absence of supragranular layer activity

Response properties of cells in the infragranular layers of cortical area 17 of the cat were examined in the absence of input from supragranular layers. Supragranular activity was silenced either reversibly by cooling the surface of cortex or permanently by making a cryogenic lesion of the supragranular layers. Visually driven responses of cells throughout the cortical column were recorded with a linear array of electrodes. Most infragranular layer cells continued to be visually responsive in the absence of supragranular layer input. These cells were similar to normal infragranular layer cells on measures of visual responsiveness, orientation selectivity, and direction selectivity. Special complex, but not standard complex, cells were absent in layer 5 when supragranular layers were destroyed. We found no evidence for a selective effect of removal of supragranular activity on the response properties of cells in layer 6. We propose that the intracolumnar projection from the supragranular layers drives the special complex cells of layer 5, but is not necessary for the visual driving of most other infragranular layer cells. This projection does not impose selectivity for stimulus orientation or direction on the remaining active cells of the infragranular layers.     

Regional distribution of GABAA receptor binding sites in cat somatosensory and motor cortex

Inhibition in primary sensory cortex plays a role in neuronal response to periperal stimuli. For many neurons in cat primary somatosensory cortex, blockade of GABA_A receptors by bicuculline results in receptive field enlargement. The magnitude of this effect varies with the neuron's adaption characteristics and its location in particular laminae and submodality regions. To test whether these variation are correlated with the distribution of GABA_A receptors, we analyzed [³H] muscimol binding in cat primary somatosensory and motor cortical areas. The highest levels of binding were in layers IV was distinguished by highest levels were in layers V–VI. In somatosensory cortical areas, layer IV, levels of binding were significantly higher in posterior area 3b than in anterior area 3b. These difference may correspond to the rapidly adaption and slowly adapting submodality regions which have been described in this area. The laminar distribution of [³H] muscimol binding differed from that of [³H]flunitrazepam, and neither resembled the distribution of magnitude of bicuculline's effects on receptive field size. The laminar distribution of [³H] muscimol binding was highly correlated with the area density of GABA-immunoreactive neurons described in a companion study. © 1994 Wiley-Liss, Inc.     

T2 and T2∗ mapping in ex situ porcine myocardium: myocardial intravariability,temporal stability and the effects of complete coronary occlusion

International Journal of Legal Medicine - Diagnosis of ischaemia-related sudden cardiac death in the absence of microscopic and macroscopic ischaemic lesions remains a challenge for medical...     

Association of TH01 with human longevity revisited

The gene tyrosine hydroxylase 1 (TH01) has been suggested as a candidate for human longevity. A previous study has shown an association between longevity and specific alleles of the TH01 short tandem repeat (STR) polymorphism in an Italian population. This STR locus is also widely used in forensic genetics. If the TH01-longevity association could be confirmed in independent samples, this finding would have important ramifications for the use of this polymorphism in a forensic context. In the present study, we sought to replicate the previous association result by investigating 471 long-lived individuals (96-110 years) and 462 younger controls (19-75 years) from Germany. In the analyzed samples, the association between TH01 and longevity was not replicated. However, the obtained TH01 allele frequencies were consistent with published data. We observed considerable differences in the allele distribution between Germans and Italians, in particular with regard to allele 9.3, which displayed a previously undetected decreasing West-East and North-South cline across Europe. The discrepant TH01-longevity association results in Germans and Italians could therefore be due to population-specific effects. This finding highlights the need to take into consideration population genetic data when dealing with association studies.