Spatial Network Connectivity and Spatial Reasoning Ability in Children with Nonverbal Learning Disability.

Nonverbal Learning Disability (NVLD) is characterized by deficits in visual-spatial, but not verbal, reasoning. Nevertheless, the functioning of the neural circuits supporting spatial processing have yet to be assessed in children with NVLD. We compared the resting state functional connectivity of a spatial brain network among children with NVLD, children with reading disorder (RD), and typically developing (TD) children. Seventy-five participants (7-15 years old) were included in the study (20 TD, 24 NVLD, and 31 RD). Group differences in global efficiency and functional connectivity among 12 regions comprising a previously defined spatial network were evaluated. Associations with behavior were explored. Global efficiency of the spatial network associated positively with spatial ability and inversely with socioemotional problems. Within the spatial network, associations between left posterior cingulate (PCC) and right retrosplenial cortical activity were reduced in children with NVLD relative to those without spatial deficits (RD and TD). Connectivity between left PCC and right posterior cerebellum (Crus I and II) was reduced in both groups of children with learning disabilities (NVLD and RD) relative to TD children. Functional connectivity of the spatial network was atypically associated with cognitive and socioemotional performance in children with NVLD. Identifying a neurobiological substrate for NVLD provides evidence that it is a discrete clinical entity and suggests targets for treatment.

Effect of Positioning of the ROI on BMD of the Forearm and Its Subregions.

Inconsistent positioning of patients and region of interest (ROI) is known to influence the precision of bone mineral density (BMD) measurements in the spine and hip. However, it is unknown whether minor shifts in the positioning of the ROI along the shaft of the radius affect the measurement of forearm BMD and its subregions. The ultradistal (UD-), mid-, one-third, and total radius BMDs of 50 consecutive clinical densitometry patients were acquired. At baseline the distal end of the ROI was placed at the tip of the ulnar styloid as usual, and then the forearm was reanalyzed 10 more times, each time shifting the ROI 1 mm proximally. No corrections for multiple comparisons were necessary since the differences that were significant were significant at p < 0.001. The UD-radius BMD increased as the ROI was shifted proximally; the increase was significant when shifted even 1 mm proximally (p < 0.001). These same findings held true for the mid- and total radius bone density, though the percent increase with moving proximally was significantly greater for the UD radius than for the other subregions. However, there was no significant change in the one-third radius BMD when shifted proximally 1-10 mm. Minor proximal shifts of the forearm ROI substantially affect the BMD of the UD-, mid- and total radius, while having no effect on the one-third radius BMD. Since the one-third radius is the only forearm region usually reported, minor proximal shifts of the ROI should not influence forearm BMD results significantly.

Alterations of nasal mucociliary clearance in association with HIV infection and the effect of guaifenesin therapy.

OBJECTIVES: To determine if human immunodeficiency virus (HIV) infection is associated with a prolonged mucociliary clearance time (MCT) and to evaluate the effect of guaifenesin on MCT in HIV+ patients. STUDY DESIGN: A cross-sectional study comparing HIV+ and HIV- volunteers followed by a prospective, randomized, double-blind, placebo-controlled study of HIV+ patients before and after guaifenesin treatment. METHODS: Twenty-five HIV+ patients and 29 HIV- controls were enrolled and MCT was measured using the saccharin method. A separate group of 20 HIV+ patients participated in the second arm of the study and underwent saccharin testing before and after a 3-week course of guaifenesin or placebo. All study participants completed a medical history questionnaire, a sinonasal symptom (SNOT-16) survey, and were examined with both anterior rhinoscopy and rigid nasal endoscopy. RESULTS: There was a significant difference (P < .002) in the MCT between the HIV+ group (13.3 +/- SD 7.5 minutes) and the HIV- controls (9.2 +/- SD 3.9 minutes). The difference in MCT between the guaifenesin and placebo groups did not reach statistical significance (P >.05). The HIV+ group had a higher SNOT-16 score compared to HIV- controls (21.1 vs. 7.4, P < .001). Guaifenesin therapy in HIV+ patients led to a significant improvement in the SNOT-16 score (P < .05). CONCLUSIONS: Compared to HIV- controls, HIV+ patients have a prolonged MCT and more sinonasal symptoms as indicated by a higher SNOT-16 score. Guaifenesin therapy was associated with improved SNOT-16 scores, although there was not a detectable improvement in MCT. Use of guaifenesin in HIV+ patients with sinonasal disease may lead to improved patient perception of quality of life.

The ARG1-LIKE2 gene of Arabidopsis functions in a gravity signal transduction pathway that is genetically distinct from the PGM pathway.

The arl2 mutants of Arabidopsis display altered root and hypocotyl gravitropism, whereas their inflorescence stems are fully gravitropic. Interestingly, mutant roots respond like the wild type to phytohormones and an inhibitor of polar auxin transport. Also, their cap columella cells accumulate starch similarly to wild-type cells, and mutant hypocotyls display strong phototropic responses to lateral light stimulation. The ARL2 gene encodes a DnaJ-like protein similar to ARG1, another protein previously implicated in gravity signal transduction in Arabidopsis seedlings. ARL2 is expressed at low levels in all organs of seedlings and plants. arl2-1 arg1-2 double mutant roots display kinetics of gravitropism similar to those of single mutants. However, double mutants carrying both arl2-1 and pgm-1 (a mutation in the starch-biosynthetic gene PHOSPHOGLUCOMUTASE) at the homozygous state display a more pronounced root gravitropic defect than the single mutants. On the other hand, seedlings with a null mutation in ARL1, a paralog of ARG1 and ARL2, behave similarly to the wild type in gravitropism and other related assays. Taken together, the results suggest that ARG1 and ARL2 function in the same gravity signal transduction pathway in the hypocotyl and root of Arabidopsis seedlings, distinct from the pathway involving PGM.