95 research outputs found
Effect of a Lateral Wedge Insole Over a One Week Period in a Healthy Population
Medial knee osteoarthritis is a disease that is projected to affect approximately 45% of the U.S. population and is associated with significant morbidity, chronic pain, and limited activity. Laterally wedged insoles are used as an intervention to laterally shift the mechanical axis of the limb and decrease the external knee adduction moment, possibly indicating a shift in load distribution to the lateral compartment of the knee. The aim of this study was to examine the acute effects of a laterally wedged insole in those with valgus and normally aligned knees and to determine prolonged effects after the insole was worn for a one week period in a healthy population. Ten females with normally aligned knees and eight females with valgus aligned knees participated in this study. Participants walked at a normal, comfortable speed with and without the insoles during two testing sessions, before and after a one week period of wearing the insoles. Three dimensional kinetics and kinematics were recorded. Each participant\u27s mean data was analyzed using a two-way repeated measures ANOVA (group (normal, valgus) x condition (pre-wedge, pre-nonwedge, post-wedge, post-nonwedge)). The results demonstrated that the valgus aligned group exhibited a 0.17 Nm/kg reduction in knee abduction moment when compared to the normally aligned group (p=0.02). Also, the valgus aligned group had a lower knee abduction angular impulse (-0.10±0.01 Nms/kg) when compared to the normally aligned group (-0.16±0.01 Nms/kg) (p=0.00). There was a significant two-way interaction for vertical GRF at the instance of peak knee abduction moment (p=0.01). An independent t-test showed the valgus participants had a higher vertical GRF (12.04±1.42 N/kg) when compared to the normal participants (10.7±1.27 N/kg) during the post-nonwedge condition (p=0.046). A paired t-test revealed that the post-nonwedge condition exhibited a 0.40 N/kg decrease from the post-wedge condition in normal participants (p=0.006). Normal participants also exhibited a significant difference (p=0.007) between the post-nonwedge condition (10.7±1.27 N/kg) and the pre-wedge condition (11.2±0.89 N/kg). For the valgus group, participants exhibited a 0.43 N/kg decrease when the wedge was inserted during the post session (p=0.046). There was also a significant difference (p=0.045) between the post-nonwedge condition (12.0±1.42 N/kg) and the pre-nonwedge condition (11.4±1.20 N/kg). These results did not show a significant decrease in knee abduction moment; however, the differences seen in vertical GRF coincided with knee flexion angles. The valgus group demonstrated decreased vertical GRF and increased knee flexion with the insole, which could lead to a small decrease in knee abduction moment
Cortisol, cytokines, and hippocampal volume interactions in the elderly
Separate bodies of literature report that elevated pro-inflammatory cytokines and cortisol negatively affect hippocampal structure and cognitive functioning, particularly in older adults. Although interactions between cytokines and cortisol occur through a variety of known mechanisms, few studies consider how their interactions affect brain structure. In this preliminary study, we assess the impact of interactions between circulating levels of IL-1Beta, IL-6, IL-8, IL-10, IL-12, TNF-alpha, and waking cortisol on hippocampal volume. Twenty-eight community-dwelling older adults underwent blood draws for quantification of circulating cytokines and saliva collections to quantify the cortisol awakening response. Hippocampal volume measurements were made using structural magnetic resonance imaging. Elevated levels of waking cortisol in conjunction with higher concentrations of IL-6 and TNF-alpha were associated with smaller hippocampal volumes. In addition, independent of cortisol, higher levels of IL-1beta and TNF-alpha were also associated with smaller hippocampal volumes. These data provide preliminary evidence that higher cortisol, in conjunction with higher IL-6 and TNF-alpha, are associated with smaller hippocampal volume in older adults. We suggest that the dynamic balance between the hypothalamic-pituitary adrenal axis and inflammation processes may explain hippocampal volume reductions in older adults better than either set of measures do in isolation
Neuroanatomical Structure of the Spinner Dolphin (Stenella longirostris orientalis) Brain From Magnetic Resonance Images
High-resolution magnetic resonance (MR) images of the brain of an adult spinner dolphin (Stenella longirostris orientalis) were acquired in the coronal plane at 55 antero-posterior levels. From these scans a computergenerated set of resectioned virtual images in the two remaining orthogonal planes was constructed with the use of the VoxelView and VoxelMath (Vital Images, Inc.) programs. Neuroanatomical structures were labeled in all three planes, providing the first labeled anatomical description of the spinner dolphin brain
Magnetic Resonance Images of the Brain of a Dwarf Sperm Whale (Kogia simus)
Cetacean (dolphin, whale and porpoise) brains are among the least studied mammalian brains because of the difficulty of collecting and histologically preparing such relatively rare and large specimens. Among cetaceans, there exist relatively few studies of the brain of the dwarf sperm whale (Kogia simus). Magnetic resonance imaging (MRI) offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Therefore, MRI has become a critical tool in the study of the brain of cetaceans and other large species. This paper represents the first MRI-based anatomically labelled three-dimensional description of the dwarf sperm whale brain. Coronal plane sections of the brain of a sub-adult dwarf sperm whale were originally acquired and used to produce virtual digital scans in the other two orthogonal spatial planes. A sequential set of images in all three planes has been anatomically labelled and displays the proportions and positions of major neuroanatomical features
Neuroanatomy of the Harbor Porpoise (Phocoena phocoena) From Magnetic Resonance Images
Cetacean (dolphin, whale, and porpoise) brains are among the least-studied mammalian brains because of the formidability of collecting and histologically preparing such relatively rare and large specimens. Among cetaceans, there exist relatively few studies of the brain of the harbor porpoise (Phocoena phocoena). Magnetic resonance imaging (MRI) offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Therefore, MRI has become a critical tool in the study of the brain of cetaceans and other large species. This article represents the first MRI-based anatomically labeled three-dimensional description of the harbor porpoise brain. Coronal plane sections of the brain of a young harbor porpoise were originally acquired and used to produce virtual digital scans in the other two orthogonal spatial planes. A sequential set of images in all three planes has been anatomically labeled and displays the proportions and positions of major neuroanatomical features. These images allow for the visualizing of the distinctive features of the harbor porpoise brain from various orientations by preserving the gross morphological structure of the specimen
Anatomy and Three-Dimensional Reconstructions of the Brain of a Bottlenose Dolphin (Tursiops truncatus) From Magnetic Resonance Images
Cetacean (dolphin, whale, and porpoise) brains are among the least studied mammalian brains because of the formidability of collecting and histologically preparing such relatively rare and large specimens. Magnetic resonance imaging offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Furthermore, internal structures can be analyzed in their precise anatomic positions, which is difficult to accomplish after the spatial distortions often accompanying histological processing. In this study, images of the brain of an adult bottlenose dolphin, Tursiops truncatus, were scanned in the coronal plane at 148 antero-posterior levels. From these scans a computer-generated three-dimensional model was constructed using the programs Voxel-View and VoxelMath (Vital Images, Inc.). This model, wherein details of internal and external morphology are represented in three-dimensional space, was then resectioned in orthogonal planes to produce corresponding series of virtual sections in the horizontal and sagittal planes. Sections in all three planes display the sizes and positions of major neuroanatomical features such as the arrangement of cortical lobes and subcortical structures such as the inferior and superior colliculi, and demonstrate the utility of MRI for neuroanatomical investigations of dolphin brains
Neurocognitive markers of passive suicidal ideation in late-life depression
Objectives: (1) To delineate whether cognitive flexibility and inhibitory ability are neurocognitive markers of passive suicidal ideation (PSI), an early stage of suicide risk in depression and (2) to determine whether PSI is associated with volumetric differences in regions of the prefrontal cortex (PFC) in middle-aged and older adults with depression.
Design: Cross-sectional study.
Setting: University medical school.
Participants: Forty community-dwelling middle-aged and older adults with depression from a larger study of depression and anxiety (NIMH R01 MH091342-05 PI: O\u27Hara).
Measurements: Psychiatric measures were assessed for the presence of a DSM-5 depressive disorder and PSI. A neurocognitive battery assessed cognitive flexibility, inhibitory ability, as well as other neurocognitive domains.
Results: The PSI group (n = 18) performed significantly worse on cognitive flexibility and inhibitory ability, but not on other neurocognitive tasks, compared to the group without PSI (n = 22). The group with PSI had larger left mid-frontal gyri (MFG) than the no-PSI group. There was no association between cognitive flexibility/inhibitory ability and left MFG volume.
Conclusions: Findings implicate a neurocognitive signature of PSI: poorer cognitive flexibility and poor inhibitory ability not better accounted for by other domains of cognitive dysfunction and not associated with volumetric differences in the left MFG. This suggests that there are two specific but independent risk factors of PSI in middle- and older-aged adults
Associations between hippocampal morphology, diffusion characteristics, and salivary cortisol in older men
High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types. The hippocampus is thought to be particularly susceptible to such effects, and though findings from animal models and human patients provide some support for this hypothesis, evidence for associations between elevated GCs and lower hippocampal volumes in older age (when GC levels are at greater risk of dysregulation) is inconclusive. To address the possibility that the effects of GCs in non-pathological ageing may be too subtle for gross volumetry to reliably detect, we analyse associations between salivary cortisol (diurnal and reactive measures), hippocampal morphology and diffusion characteristics in 88 males, aged ∼73 years. However, our results provide only weak support for this hypothesis. Though nominally significant peaks in morphology were found in both hippocampi across all salivary cortisol measures (standardised β magnitudes < 0.518, p(uncorrected) > 0.0000003), associations were both positive and negative, and none survived false discovery rate correction. We found one single significant association (out of 12 comparisons) between a general measure of hippocampal diffusion and reactive cortisol slope (β = 0.290, p = 0.008) which appeared to be driven predominantly by mean diffusivity but did not survive correction for multiple testing. The current data therefore do not clearly support the hypothesis that elevated cortisol levels are associated with subtle variations in hippocampal shape or microstructure in non-pathological older age
Differential effects of hunger and satiety on insular cortex and hypothalamic functional connectivity
The insula cortex and hypothalamus are implicated in eating behaviour, and contain receptor sites for peptides and hormones controlling energy balance. The insula encompasses multi-functional subregions, which display differential anatomical and functional connectivities with the rest of the brain. This study aimed to analyse the effect of fasting and satiation on the functional connectivity profiles of left and right anterior, middle, and posterior insula, and left and right hypothalamus. It was hypothesized that the profiles would be altered alongside changes in homeostatic energy balance. Nineteen healthy participants underwent two 7-min resting state functional magnetic resonance imaging scans, one when fasted and one when satiated. Functional connectivity between the left posterior insula and cerebellum/superior frontal gyrus, and between left hypothalamus and inferior frontal gyrus was stronger during fasting. Functional connectivity between the right middle insula and default mode structures (left and right posterior parietal cortex, cingulate cortex), and between right hypothalamus and superior parietal cortex was stronger during satiation. Differences in blood glucose levels between the scans accounted for several of the altered functional connectivities. The insula and hypothalamus appear to form a homeostatic energy balance network related to cognitive control of eating; prompting eating and preventing overeating when energy is depleted, and ending feeding or transferring attention away from food upon satiation. This study provides evidence of a lateralized dissociation of neural responses to energy modulations
ChemInform Abstract: STUDIES ON THE KINETICS AND REACTION TECHNOLOGY OF THE FISCHER-TROPSCH SYNTHESIS OF 1-ALKENES
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