Craniofacial serial dimensions related to age, sex, and cleft-type from six months of age to two years.

The first two postnatal years are a time of rapid craniofacial growth. We selected 30 cleft lip/palate children, each seen at 6, 12, 18, 24 months, at which time lateral X-ray headfilms were taken. There were five boys, five girls, in each of three cleft-types: cleft palate only (CP), unilateral cleft lip/palate (UCLP), and bilateral cleft lip/palate (BCLP). Three dimensions were selected: 1) anterior cranial base (S-N); 2) upper face height (N-Pt.A); 3) maxillary depth (Pt.A-Ptm). All were in the midsagittal plane. This is a repeated measures study on the factor patient age, so that for each combination of sex and cleft-type the same subject was measured at the four levels of patient age. The multiple comparison technique utilized was the Newman-Keuls Procedure. There is no significant joint effect in the 6-24 months period. The factors seem to operate singly. There is no main effect due to the factor sex. Dimensions N-Pt.A. and Pt.A-Ptm show a significant main effect due to the factor cleft-type. There is a highly significant main effect due to the patient age factor.     

The effects of cognitive loading on balance control in patients with multiple sclerosis

The aim of this study was to compare the effects of concurrent cognitive task (silent backward counting) on balance performance between two groups of multiple sclerosis (MS) (n = 23) and healthy (n = 23) participates. Three levels of postural difficulty were studied on a force platform, i.e. rigid surface with eyes open, rigid surface with eyes closed, and foam surface with eyes closed. A mixed model analysis of variance showed that under difficult sensory condition of foam surface with eyes closed, execution of concurrent cognitive task caused a significant decrement in variability of sway velocity in anteroposterior direction for the patient group (P < 0.01) while this was not the case for healthy participants (P = 0.22). Also, the variability of sway velocity in mediolateral direction was significantly decreased during concurrent execution of cognitive task in patient group (P < 0.01) and not in healthy participants (P = 0.39). Furthermore, in contrast to single tasking, dual tasking had the ability to discriminate between the 2 groups in all conditions of postural difficulty. In conclusion, findings of variability in sway velocity seem to confirm the different response to cognitive loading between two groups of MS and healthy participants.     

Combined time-resolved and high-spatial-resolution 3D MRA using an extended adaptive acquisition

PURPOSE: To combine the benefits of time-resolved dynamic imaging and single elliptical centric acquisitions in a reasonable scan time. MATERIALS AND METHODS: A time series of images with moderate spatial resolution was acquired using the 3D Time-Resolved Imaging of Contrast KineticS (3D TRICKS) technique with elliptical centric encoding during contrast arrival. Following venous opacification, a complete large centrically encoded k-space volume was acquired. The high-spatial-frequency portions of this volume were combined with a 3D TRICKS time frame to form a high-resolution image. An additional single image is formed by suppressing background and signal averaging all acquired data, including post-venous low-spatial-frequency data. For this image, 2D temporal correlation analysis is used to suppress low-spatial-frequency vein contributions. Arrival time and spatial correlations are used to suppress background. RESULTS: The 3D TRICKS time frame may be selected to ensure a combined high-resolution image that has optimal central k-space sampling for any vascular region. The single image formed by signal averaging all acquired data has increased contrast-to-noise (CNR) and signal-to-noise (SNR) ratios. CONCLUSION: The advantages of time-resolved and high-spatial-resolution imaging were combined using an extended dual-phase acquisition. Some SNR and CNR gain was achieved by signal averaging. This process is facilitated by background and vein suppression.     

Modulations in oscillatory activity with amplitude asymmetry can produce cognitively relevant event-related responses

Event-related responses and oscillatory activity are typically regarded as manifestations of different neural processes. Recent work has nevertheless revealed a mechanism by which slow event-related responses are created as a direct consequence of modulations in brain oscillations with nonsinusoidal properties. It remains unknown if this mechanism applies to cognitively relevant event-related responses. Here, we investigated whether sustained event-related fields (ERFs) measured during working memory maintenance can be explained by modulations in oscillatory power. In particular, we focused on contralateral delayed activity (CDA) typically observed in working memory tasks in which hemifield specific attention is manipulated. Using magnetoencephalography, we observed sustained posterior ERFs following the presentation of the memory target. These ERFs were systematically lateralized with respect to the hemisphere in which the target was presented. A strikingly similar pattern emerged for modulations in alpha (9–13 Hz) power. The alpha power and ERF lateralization were strongly correlated over subjects. Based on a mechanistic argument pertaining to the nonsinusoidal properties of the alpha activity, we conclude that the ERFs modulated by working memory are likely to be directly produced by the modulations in oscillatory alpha activity. Given that posterior alpha activity typically reflects disengagement, we conclude that the CDA is not attributable to an additive process reflecting memory maintenance per se but, rather, is a consequence of how attentional resources are allocated.     

Determination of aflatoxins in imported rice to Iran

Aflatoxins (AFs) are highly toxic and carcinogenic secondary fungal metabolites and have been detected in various food commodities including cereals. Rice were imported to Iran during March 2006–March 2007 analyzed for aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) using immunoaffinity column and quantitated by HPLC. In this regard, 71 rice samples were collected. After dividing samples to sub-samples, AF analyses were done. Among 71 samples analyzed, AFB1 was detected in 59 samples (83% of the total). The mean of AFB1 was 1.89 ng/g for all samples (with the not detected samples taken as zero). Total AF (AFT) was detected in 59 samples (83% of the total). The mean of AFT was 2.09 ng/g for all samples. AFB1 level in two samples (2.8%) was above the maximum tolerated level (MTL) of AFB1 in Iran (5 ng/g). Regarding AFT, the mean contamination level (2.09 ng/g) was lower than MTL of AFT in rice in Iran as well as lower than maximum level of EU for AFT (4 ng/g), and only nine samples had levels above the MTL of EU in AFT.     

Multishot partial-k-space EPI for high-resolution fMRI demonstrated in a rat whisker barrel stimulation model at 3T.

A multishot partial-k-space EPI technique is presented and validated by fMRI at high spatial resolution. High-resolution phase maps corrected by phase-encoded reference scans have less off-resonance effects. Phantom studies demonstrate that this method can substantially improve partial-k-space EPI image formation. BOLD fMRI at submillimeter spatial resolution (156 x 156 x 2000 microm(3), 0.049 microl) was achieved in a rat whisker barrel stimulation model using this technique. The study included eight rats, five of which were administered an intravascular contrast agent (monocrystalline iron oxide nanocolloid (MION)) after the BOLD experiments. In two rats the highest BOLD responses were in the deep layers (IV-VI), and in six rats the highest responses were on the surface and in the deep cortical layers. Most of the pixels that exhibited high BOLD responses had high blood volume weightings. The benefits of this technique are expected to increase for high-resolution fMRI at higher magnetic fields, where T(2) (*) is shorter.     

3D Time-resolved contrast-enhanced MR DSA: Advantages and tradeoffs

The 3D TRICKS method for contrast-enhanced, time-resolved MR DSA has been recently described. In this paper, computer simulations are used to investigate the relative frame rate, temporal window, artery-vein temporal separation, contrast-to-noise ratio, and spatial resolution of TRICKS and conventional scans for breath-hold and non-breath-hold applications. For non-breath-hold applications, TRICKS can be coofigured to provide increased CNR or spatial resolution at an increased frame rate, but with a longer temporal window when compared with a series of conventional scans in which the central portion of k-space is sampled at the same rate as for the TRICKS scans. For breath-hold applications, TRICKS typically provides three images with 75% of the conventional single acquisition spatial resolution and is more tolerant of variations in contrast curve shape within the field of view.     

Epidemiological aspects of rotavirus infection in Ahwaz, Iran

Rotavirus is the major cause of diarrhoea in children worldwide. In this study, conducted in the city of Ahwaz, Iran, during November 2001-March 2002, stool samples from 200 inpatient (n=63) and outpatient (n=137) children aged 1-24 month(s) were analyzed. Polyacrylamide gel electrophoresis was used for isolating rotavirus. Rotavirus was isolated from 36 (26.3%) of the 137 stool samples of outpatients and from 23 (36.5%) of the 63 stool samples of inpatients. The overall frequency of rotavirus in this population was 29.5%. The highest detection of rotavirus was made in children aged 7-12 months, which demonstrated that the relationship between age and rate of rotaviral infection was statistically significant (p < 0.05). The predominant electrophoretic pattern detected was the long (L) electrophoretype (46 of 59; 78%), followed by the short (S) electrophoretype (12 of 59; 20.3%). One strain had a mixed pattern. Such analysis throughout Iran would assist in developing sound guidelines for the prevention of rotavirus infections.