Memory in Autistic Spectrum Disorder

Behavioral evidence concerning memory in high-functioning forms of autism (HFA) and in moderately low-functioning autism (M-LFA) is reviewed and compared. Findings on M-LFA are sparse. However, it is provisionally concluded that memory profiles in HFA and M-LFA (relative to ability-matched controls) are similar, but that declarative memory impairments are more extensive in M-LFA than in HFA. Specifically, both groups have diminished memory for emotion- or person-related stimuli. Regarding memory for non-social stimuli, both groups probably have mental-age appropriate nondeclarative memory; and within declarative memory, both groups have mental-age appropriate immediate free recall of within-span or supra-span lists of unrelated items, as well as cued recall and paired associate learning. By contrast, recognition is largely unimpaired in HFA but moderately impaired in M-LFA; and free recall of meaningful or structured stimuli is moderately impaired in HFA but more severely impaired in M-LFA. Theoretical explanations of data on declarative memory in HFA identify problems in the integrative processing, or the consolidation and storage, of complex stimuli; or a specific problem of recollection. Proposed neural substrates include the following: disconnectivity of primary sensory and association areas; dysfunctions of medial prefrontal cortex, hippocampus or posterior parietal lobe; or combinations of these associated with neural disconnectivity. Hypothetically, perirhinal dysfunction might explain the more extensive declarative memory impairments in M-LFA. Foreseeable consequences of uneven memory abilities in HFA and M-LFA are outlined, including possible effects on language and learning in M-LFA. Finally, priorities for future research are identified, highlighting the urgent need for research on memory in lower-functioning individuals

Nitric oxide metabolite levels during the ectopic osteoinduction in rats

Abstract Nitric oxide (NO) is a cell-signaling molecule that has diverse biological functions. Recent evidence suggests that its production may regulate the metabolism of the osteoblasts and osteoclasts. The aim of this study was to evaluate levels of nitrite and nitrates (NO metabolites) during ectopic osteoinduction in rats. Eighteen male Sprague–Dawley rats (body weight 200–300 g) were used in this study. All animals were anesthetized and the right and left flank areas were shaved, and under aseptic conditions, a muscular pouch was created in each flank: the left was filled with 20 mg of demineralized bone matrix and the right remained empty (sham). Radiographs were taken at 2, 4, and 6 weeks after surgery to trace the ectopic bone formation and muscle mineralization. Blood samples were taken before (as baseline values) and at 2, 4, and 6 weeks after surgery. The mean values of NO metabolites after 6 weeks were significantly higher (p<0.05) than baseline data and at 2 weeks post-surgery. Results from this study indicate that the ectopic osteoinduction caused increased activity of the osteoblasts which subsequently caused increased serum levels of NO metabolites (nitrites and nitrates)

La mineralogía de la arcilla del suelo Nipe

The mineralogy of Nipe clay was characterized by means of X-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), BET surface area, and chemical analysts. The major components of the clay fraction are goethite, gibbsite, hematite and kaolinite. Goethite is the predominant iron oxide as indicated by the high intensity of the XRD peaks. The unit cell dimensions of goethite, estimated from the XRD data, were a = 4.603 Å, b = 9.806 Å&nbsp;and c = 3.002 Å. The unit cell dimensions of hematite were a = 5.037 Å, and c = 13.735 Å. The extent of aluminum substitution in goethite and hematite was also estimated from the XRD data. The mole % Al in goethite, based on the d (111) value, was 15.57 mole percent, whereas when the a-dimension of the unit cell was used, a value of 12.86 mole percent was obtained. The estimated mole percent Al substitution in hematite was 0.67. The hematite/goethite ratio as estimated from the relative intensities of the 104 peak of hematite and the 110 peak of goethite was 0.51. Kaolinite showed a high capacity to absorb IR radiation as indicated by strong absorption peaks around 1000 and 3700 cm-1. The surface area of the clay as determined by the BET method was 55.26 m2/g. The ratio of Feox/Fed was very low (1.17x10-2), indicating that the iron oxides occur in well crystallized form.La mineralogía de la arcilla del suelo Nipe se caracterizó usando difracción de rayos X, análisis termal, espectroscopia de infrarojo, área superficial (BET) y análisis químico. Los principales componentes minerales de la arcilla son goetita, gibsita, hematita y caolinita. La intensidad de los picos correspondientes a goetita, revelada mediante el análisis de rayos X, indica que este mineral es el óxido de Fe predominante en la arcilla del suelo Nipe. Los parámetros estructurales de la celda unitaria de goetita, estimados del análisis de rayos X, fueron a = 4.603 Å, b = 9.806 Å, y c = 3.002 Å. Los parámetros estructurales de hematita fueron: a = 5.037 Å&nbsp;y c = 13.735 Å. De los datos de rayos X también se estimó el porcentaje molar de aluminio en goetita y hematita. Para el caso particular de la goetita, el porcentaje de Al se estimó a base del la distancia interplanar d(111) y a base del tamaño de la unidad estructural-a de la celda unitaria, obteniéndose valores de 15.57 y 12.86%, respectivamente, El porcentaje de aluminio en la hematita fue de 0.67%, y se estimó a base del tamaño de la unidad estructural-a de la celda unitaria. Se obtuvo una proporción de hematita/goetita de 0.51. La caolinita demostró gran capacidad para absorber la radiación infrarroja según lo indican los picos de absorción en la cercanía de los 1000 y 3700 cm-1. El área de superficie de la arcilla fue de 55.26 m2/g. El contenido de óxidos amorfos fue muy bajo (Feox/Fed&nbsp;= 1.17x 10-2), lo que indica que los óxidos de hierro están mayormente en forma cristalina