Engagement of gaze in capturing targets for future sequential manual actions

We investigated the role of saccadic gaze fixations in encoding target locations for planning a future manual task consisting of a sequence of discrete target-oriented actions. We hypothesized that fixations of the individual targets are necessary for accurate encoding of target locations and that there is a transfer of sequence information from visual encoding to manual recall. Subjects viewed four targets presented at random positions on a screen. After various delays following target extinction, the subjects marked the remembered target locations on the screen with the tip of a hand-held stick. When the targets were presented simultaneously among distracting elements, the overall accuracy of marking increased with presentation time and total number of targets fixated because the subjects had to serially fixate the individual targets to locate them. Without distractors, the marking accuracy was similarly high regardless of duration of target presentation (0.25-8 s) and number of targets fixated; it was comparable to that with distractors when all four targets had been fixated. This indicates parallel encoding of target locations largely based on peripheral vision. Location memory was stable in these tasks over the delay periods investigated (0.5-8 s). With parallel encoding there was a "shrinkage" in the visuomotor transformation, i.e., the distances between the markings were systematically smaller than the corresponding inter-target distances. When the targets were presented sequentially without distractors, marking accuracy improved with the total number of targets fixated and shrinkage in the visuomotor transformation occurred only with parallel encoding, i.e., when subjects did not fixate the targets. In all experimental conditions for trials in which targets were fixated during encoding, there was little correspondence between the marking sequence and the sequence in which the targets were fixated. We conclude that subjects benefit from fixating targets for subsequent target-oriented manual actions when the targets are presented among distractors and when presented sequentially; when distinct targets are presented simultaneously against a blank background, they are efficiently encoded in parallel largely by peripheral vision.     

Alveolar macrophage abnormalities in rabbits exposed to low concentrations of trivalent chromium

Rabbits were exposed by inhalation to a trivalent chromium compound (Cr(NO3)3) at a mean chromium concentration of 0.6 or 2.3 mg/m3 for about 4 months, 5 days/week and 6 hr/day. Light microscopic examination of the lungs revealed that both chromium levels induced a nodular intraalveolar accumulation of enlarged macrophages with granular, eosinophilic cytoplasm. Some macrophages were multinucleated and some showed advanced degenerative changes with disruption of cellular borders and nuclear pyknosis. The changes were most prominent in rabbits exposed to the high concentration and were in some areas associated with a mild interstitial infiltration of lymphocytes, neutrophils, and eosinophils. Electron microscopic examination of macrophages lavaged from the lungs revealed numerous enlarged lysosomes with membranous structures, distinct rounded inclusions, which by X-ray microanalysis were found to contain high amounts of chromium, and increased numbers of laminated inclusions probably representing ingested surfactant. The number of macrophages with a smooth surface was significantly increased. The macrophages in the lung tissue showed the same changes and in addition nodules of multinucleated "giant" cells were found. Morphometric estimation of the volume density of the type II cells did not reveal any significant differences between controls and rabbits exposed to the high concentration of chromium. In spite of the elevated number of laminated structures in the macrophages the amounts of phosphatidylcholine and 1,2-dipalmitoylphosphatidylcholine were not significantly increased in the lung. This indicates a reduced catabolism of surfactant by the alveolar macrophages.     

Blue spotted bladder--a manifestation of bladder amyloidosis. A case report

Bladder amyloidosis may represent a life-threatening condition, but may also be associated with milder clinical symptoms. Herein, we report two older males with a different type of apparently mild bladder amyloidosis, presenting as the "blue spotted bladder".     

The effect of acute zimeldine and alaproclate administration on the acquisition of two-way active avoidance: Comparison with other antidepressant agents,test of selectivity and sub-chronic studies

The dose-dependent effect of acute zimeldine and alaproclate treatment upon the acquisition of two-way and one-way active avoidance in the rat was studied in a single-session and in a repeated-sessions design. Zimeldine (5–20 mg/kg, IP), but not alaproclate, caused disruptions of two-way avoidance acquisition. Acquisition deficits were also caused by citalopram and fluoxetine but not the other antidepressant drugs tested. Zimeldine, but not alaproclate or desipramine, caused a slight but non-significant impairment of one-way active avoidance; neither zimeldine nor alaproclate produced any effects upon fear conditioning and retention testing. The long-term action of p-chloroamphetamine (2×10 mg/kg) antagonised the acute zimeldine effect totally, and chronic treatment with zimeldine (15 days, 1×50 mol/kg) and chlorimipramine (15 days, 2×10 mol/kg) also caused some partial blockade of the two-way avoidance deficit. These data seem to suggest some involvement of serotonin (5-HT) in the observed disruptions of two-way active avoidance caused by acute zimeldine treatment.     

Transorbital endoscopic approaches to the skull base: a systematic literature review and anatomical description

Neurosurgical Review - Transorbital endoscopic approaches are increasing in popularity as they provide corridors to reach various areas of the ventral skull base through the orbit. They can be used...     

Sarcopenia Definitions as Predictors of Fracture Risk Independent of FRAX®, Falls,and BMD in the Osteoporotic Fractures in Men (MrOS) Study: A Meta-Analysis

Dual-energy X-ray absorptiometry (DXA)-derived appendicular lean mass/height² (ALM/ht²) is the most commonly used estimate of muscle mass in the assessment of sarcopenia, but its predictive value for fracture is substantially attenuated by femoral neck (fn) bone mineral density (BMD). We investigated predictive value of 11 sarcopenia definitions for incident fracture, independent of fnBMD, fracture risk assessment tool (FRAX^®) probability, and prior falls, using an extension of Poisson regression in US, Sweden, and Hong Kong Osteoporois Fractures in Men Study (MrOS) cohorts. Definitions tested were those of Baumgartner and Delmonico (ALM/ht² only), Morley, the International Working Group on Sarcopenia, European Working Group on Sarcopenia in Older People (EWGSOP1 and 2), Asian Working Group on Sarcopenia, Foundation for the National Institutes of Health (FNIH) 1 and 2 (using ALM/body mass index [BMI], incorporating muscle strength and/or physical performance measures plus ALM/ht²), and Sarcopenia Definitions and Outcomes Consortium (gait speed and grip strength). Associations were adjusted for age and time since baseline and reported as hazard ratio (HR) for first incident fracture, here major osteoporotic fracture (MOF; clinical vertebral, hip, distal forearm, proximal humerus). Further analyses adjusted additionally for FRAX-MOF probability (n = 7531; calculated ± fnBMD), prior falls (y/n), or fnBMD T-score. Results were synthesized by meta-analysis. In 5660 men in USA, 2764 Sweden and 1987 Hong Kong (mean ages 73.5, 75.4, and 72.4 years, respectively), sarcopenia prevalence ranged from 0.5% to 35%. Sarcopenia status, by all definitions except those of FNIH, was associated with incident MOF (HR = 1.39 to 2.07). Associations were robust to adjustment for prior falls or FRAX probability (without fnBMD); adjustment for fnBMD T-score attenuated associations. EWGSOP2 severe sarcopenia (incorporating chair stand time, gait speed, and grip strength plus ALM) was most predictive, albeit at low prevalence, and appeared only modestly influenced by inclusion of fnBMD. In conclusion, the predictive value for fracture of sarcopenia definitions based on ALM is reduced by adjustment for fnBMD but strengthened by additional inclusion of physical performance measures. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).