The influence of pre-radiation salivary flow rates and radiation dose on parotid salivary gland dysfunction in patients receiving radiotherapy for head and neck cancers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72238/1/j.1754-4505.1998.tb00913.x.pd

In Vivo Evaluation of the Presence of Bone Marrow in Cortical Porosity in Postmenopausal Osteopenic Women

This is the first observational study examining cortical porosity in vivo in postmenopausal osteopenic women and to incorporate data from two different imaging modalities to further examine the nature of cortical porosity. The goal of this study was to combine high-resolution peripheral computed tomography (HR-pQCT) images, which contain high spatial resolution information of the cortical structure, and magnetic resonance (MR) images, which allow the visualization of soft tissues such as bone marrow, to observe the amount of cortical porosity that contains bone marrow in postmenopausal osteopenic women. The radius of 49 and the tibia of 51 postmenopausal osteopenic women (age 56 ± 3.7) were scanned using both HR-pQCT and MR imaging. A normalized mutual information registration algorithm was used to obtain a three-dimensional rigid transform which aligned the MR image to the HR-pQCT image. The aligned images allowed for the visualization of bone marrow in cortical pores. From the HR-pQCT image, the percent cortical porosity, the number of cortical pores, and the size of each cortical pore was determined. By overlaying the aligned MR and HR-pQCT images, the percent of cortical pores containing marrow, the number of cortical pores containing marrow, and the size of each cortical pore containing marrow were measured. While the amount of cortical porosity did not vary greatly between subjects, the type of cortical pore, containing marrow vs. not containing marrow, varied highly between subjects. The results suggest that cortical pore spaces contain components of varying composition, and that there may be more than one mechanism for the development of cortical porosity

Characterization of a Drosophila Alzheimer's Disease Model: Pharmacological Rescue of Cognitive Defects

Transgenic models of Alzheimer's disease (AD) have made significant contributions to our understanding of AD pathogenesis, and are useful tools in the development of potential therapeutics. The fruit fly, Drosophila melanogaster, provides a genetically tractable, powerful system to study the biochemical, genetic, environmental, and behavioral aspects of complex human diseases, including AD. In an effort to model AD, we over-expressed human APP and BACE genes in the Drosophila central nervous system. Biochemical, neuroanatomical, and behavioral analyses indicate that these flies exhibit aspects of clinical AD neuropathology and symptomology. These include the generation of Aβ40 and Aβ42, the presence of amyloid aggregates, dramatic neuroanatomical changes, defects in motor reflex behavior, and defects in memory. In addition, these flies exhibit external morphological abnormalities. Treatment with a γ-secretase inhibitor suppressed these phenotypes. Further, all of these phenotypes are present within the first few days of adult fly life. Taken together these data demonstrate that this transgenic AD model can serve as a powerful tool for the identification of AD therapeutic interventions

The transcriptomic basis of oviposition behaviour in the parasitoid wasp Nasonia vitripennis

Linking behavioural phenotypes to their underlying genotypes is crucial for uncovering the mechanisms that underpin behaviour and for understanding the origins and maintenance of genetic variation in behaviour. Recently, interest has begun to focus on the transcriptome as a route for identifying genes and gene pathways associated with behaviour. For many behavioural traits studied at the phenotypic level, we have little or no idea of where to start searching for "candidate" genes: the transcriptome provides such a starting point. Here we consider transcriptomic changes associated with oviposition in the parasitoid wasp Nasonia vitripennis. Oviposition is a key behaviour for parasitoids, as females are faced with a variety of decisions that will impact offspring fitness. These include choosing between hosts of differing quality, as well as making decisions regarding clutch size and offspring sex ratio. We compared the whole-body transcriptomes of resting or ovipositing female Nasonia using a "DeepSAGE" gene expression approach on the Illumina sequencing platform. We identified 332 tags that were significantly differentially expressed between the two treatments, with 77% of the changes associated with greater expression in resting females. Oviposition therefore appears to focus gene expression away from a number of physiological processes, with gene ontologies suggesting that aspects of metabolism may be down-regulated during egg-laying. Nine of the most abundant differentially expressed tags showed greater expression in ovipositing females though, including the genes purity-of-essence (associated with behavioural phenotypes in Drosophila) and glucose dehydrogenase (GLD). The GLD protein has been implicated in sperm storage and release in Drosophila and so provides a possible candidate for the control of sex allocation by female Nasonia during oviposition. Oviposition in Nasonia therefore clearly modifies the transcriptome, providing a starting point for the genetic dissection of oviposition.Publisher PDFPeer reviewe

Femoral Bone Strength and Its Relation to Cortical and Trabecular Changes After Treatment With PTH, Alendronate, and Their Combination as Assessed by Finite Element Analysis of Quantitative CT Scans

The “PTH and Alendronate” or “PaTH” study compared the effects of PTH(1-84) and/or alendronate (ALN) in 238 postmenopausal, osteoporotic women. We performed finite element analysis on the QCT scans of 162 of these subjects to provide insight into femoral strength changes associated with these treatments and the relative roles of changes in the cortical and trabecular compartments on such strength changes. Patients were assigned to either PTH, ALN, or their combination (CMB) in year 1 and were switched to either ALN or placebo (PLB) treatment in year 2: PTH-PLB, PTH-ALN, CMB-ALN, and ALN-ALN (year 1-year 2) treatments. Femoral strength was simulated for a sideways fall using nonlinear finite element analysis of the quantitative CT exams. At year 1, the strength change from baseline was statistically significant for PTH (mean, 2.08%) and ALN (3.60%), and at year 2, significant changes were seen for the PTH-ALN (7.74%), CMB-ALN (4.18%), and ALN-ALN (4.83%) treatment groups but not for PTH-PLB (1.17%). Strength increases were primarily caused by changes in the trabecular density regardless of treatment group, but changes in cortical density and mass also played a significant role, the degree of which depended on treatment. For PTH treatment at year 1 and for ALN-ALN treatment at year 2, there were significant negative and positive strength effects, respectively, associated with a change in external bone geometry. Average changes in strength per treatment group were somewhat consistent with average changes in total hip areal BMD as measured by DXA, except for the PTH group at year 1. The relation between change in femoral strength and change in areal BMD was weak (r 2 = 0.14, pooled, year 2). We conclude that femoral strength changes with these various treatments were dominated by trabecular changes, and although changes in the cortical bone and overall bone geometry did contribute to femoral strength changes, the extent of these latter effects depended on the type of treatment

Could martial arts fall training be safe for persons with osteoporosis?: a feasibility study.

Contains fulltext : 87286.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: Osteoporosis is a well-established risk factor for fall-related hip fractures. Training fall arrest strategies, such as martial arts (MA) fall techniques, might be useful to prevent hip fractures in persons with osteoporosis, provided that the training itself is safe. This study was conducted to determine whether MA fall training would be safe for persons with osteoporosis extrapolated from the data of young adults and using stringent safety criteria. METHODS: Young adults performed sideways and forward MA falls from a kneeling position on both a judo mat and a mattress as well as from a standing position on a mattress. Hip impact forces and kinematic data were collected. For each condition, the highest hip impact force was compared with two safety criteria based on the femoral fracture load and the use of a hip protector. RESULTS: The highest hip impact force during the various fall conditions ranged between 1426 N and 3132 N. Sideways falls from a kneeling and standing position met the safety criteria if performed on the mattress (max 1426 N and 2012 N, respectively) but not if the falls from a kneeling position were performed on the judo mat (max 2219 N). Forward falls only met the safety criteria if performed from a kneeling position on the mattress (max 2006 N). Hence, forward falls from kneeling position on a judo mat (max 2474 N) and forward falls from standing position on the mattress (max 3132 N) did not meet both safety criteria. CONCLUSIONS: Based on the data of young adults and safety criteria, the MA fall training was expected to be safe for persons with osteoporosis if appropriate safety measures are taken: during the training persons with osteoporosis should wear hip protectors that could attenuate the maximum hip impact force by at least 65%, perform the fall exercises on a thick mattress, and avoid forward fall exercises from a standing position. Hence, a modified MA fall training might be useful to reduce hip fracture risk in persons with osteoporosis