A Novel Use of the Exoscope for In-Vivo Microvascular Free Flaps.

Recent innovations in camera and display technologies have created a new potential modus for the microvascular surgeon. An exoscope consists of cameras mounted to a flexible arm that broadcasts the image to a nearby high-definition monitor. This article details the experience using this emerging technology to perform microvascular anastomosis for 46 cases of head and neck free flaps reconstruction. The exoscope is compared against the operating microscope and we conclude that the exoscope is a viable substitute when performing microvascular anastomosis with some advantages in the areas of surgeon comfort and viewing angulation.

Quantitative imaging for radiotherapy purposes.

Quantitative imaging biomarkers show great potential for use in radiotherapy. Quantitative images based on microscopic tissue properties and tissue function can be used to improve contouring of the radiotherapy targets. Furthermore, quantitative imaging biomarkers might be used to predict treatment response for several treatment regimens and hence be used as a tool for treatment stratification, either to determine which treatment modality is most promising or to determine patient-specific radiation dose. Finally, patient-specific radiation doses can be further tailored to a tissue/voxel specific radiation dose when quantitative imaging is used for dose painting. In this review, published standards, guidelines and recommendations on quantitative imaging assessment using CT, PET and MRI are discussed. Furthermore, critical issues regarding the use of quantitative imaging for radiation oncology purposes and resultant pending research topics are identified.

The chronology of reindeer hunting on Norway's highest ice patches.

The melting of perennial ice patches globally is uncovering a fragile record of alpine activity, especially hunting and the use of mountain passes. When rescued by systematic fieldwork (glacial archaeology), this evidence opens an unprecedented window on the chronology of high-elevation activity. Recent research in Jotunheimen and surrounding mountain areas of Norway has recovered over 2000 finds-many associated with reindeer hunting (e.g. arrows). We report the radiocarbon dates of 153 objects and use a kernel density estimation (KDE) method to determine the distribution of dated events from ca 4000 BCE to the present. Interpreted in light of shifting environmental, preservation and socio-economic factors, these new data show counterintuitive trends in the intensity of reindeer hunting and other high-elevation activity. Cold temperatures may sometimes have kept humans from Norway's highest elevations, as expected based on accessibility, exposure and reindeer distributions. In times of increasing demand for mountain resources, however, activity probably continued in the face of adverse or variable climatic conditions. The use of KDE modelling makes it possible to observe this patterning without the spurious effects of noise introduced by the discrete nature of the finds and the radiocarbon calibration process.

Local study of fissure caries by Fourier transform infrared microscopy and X-ray diffraction using synchrotron radiation.

Investigations of intact dental enamel as well as carious-affected human dental enamel were performed using infrared spectromicroscopy and X-ray diffraction applying synchrotron radiation. Caries of enamel was shown to be characterized by an increase in the number of deformation and valence vibrations for N-C-O, N-H and C=O bonds, a decrease of the crystallinity index, and by the absence of the preferable orientation of hydroxyapatite crystals within the affected enamel. This indicates the presence of destructive processes in the organic matrix of hard tooth tissues.

Association among amyloid plaque, lipid, and creatine in hippocampus of TgCRND8 mouse model for Alzheimer disease.

Amyloid peptide (Aß) aggregation in the brain is a characteristic feature of Alzheimer disease (AD). Previously, we reported the discovery of focally elevated creatine deposits in brain tissue from TgCRND8 mice, which express double mutant (K670N/M671L and V717F) amyloid protein precursor. In this study, frozen hippocampal tissue sections from 5-, 8-, 11-, 14-, and 17-month old TgCRND8 and littermate control mice were examined with Fourier transform infrared microspectroscopy to explore the distribution of lipid, creatine, and dense core plaque deposits. Lipid distribution throughout the hippocampus was similar in transgenic (Tg) and non-Tg littermates at all ages. Dense core plaques were always found to lie within a thin (30-50 µm) lipid envelope, confirmed by imaging through serial sections. Creatine deposits were found in all TgCRND8 mice; the extent of deposition increased with age. Minor creatine deposits appeared in the oldest littermate controls. Distribution in the serial sections showed moderate correlation between layers, slightly disturbed by the freeze/thaw process. Creatine deposits in Tg mice were not specifically co-localized with plaques or lipid halos. The dimension of the lipid envelope is comparable with that of the diffuse halo of nonaggregated amyloid, implying a dynamic association in vivo, postulated to have a significant role in the evolving neurotoxicity.

A sensitive method for examining whole-cell biochemical composition in single cells of filamentous fungi using synchrotron FTIR spectromicroscopy.

Cell function is related to cell composition. The asexual state of filamentous fungi (molds and mildews) has two main life cycle stages: vegetative hyphae for substrate colonization and nutrient acquisition, and asexual spores for survival and dispersal. Hyphal composition changes over a few tens of microns during growth and maturation; spores are different from hyphae. Most biochemical analyses are restricted to studying a few components at high spatial resolution (e.g. histochemistry) or many compounds at low spatial resolution (e.g. GC-MS). Synchrotron FTIR spectromicroscopy can be used to study fungal cell biology by fingerprinting varieties of carbohydrates, proteins, and lipids at about 6 microm spatial resolution. FTIR can distinguish fungal species and changes during hyphal growth, and reveals that even fungi grown under optimal vs mildly stressed conditions exhibit dramatic biochemical changes without obvious morphological effects. Here we compare hypha and spore composition of two fungi, Neurospora and Rhizopus. There are clear biochemical changes when Neurospora hyphae commit to spore development, during spore maturation and following germination, many of which are consistent with results from molecular genetics, but have not been shown before at high spatial resolution. Rhizopus spores develop within a fluid-containing sporangium that becomes dry at maturity. Rhizopus spores had similar protein content and significantly more carbohydrate than the sporangial fluid, both of which are novel findings.

Pin1 protein associates with neuronal lipofuscin: potential consequences in age-related neurodegeneration.

Pin1 protein is a peptidyl-prolyl cis-trans isomerase that modulates the activity of a range of proteins involved in cell function. We and others have demonstrated neuronal Pin1 deficits in Alzheimer's disease (AD) and have shown similar deficits in frontotemporal dementia and in aging. Pin1 may, in fact, be a susceptibility factor; others have shown that Pin1 depletion causes apoptosis in HeLa cells. Further, patterns of AD pathology correlate with regions of lower Pin1 expression in normal human brain; Pin1 knockout mice suffer neurodegeneration; and Pin1 can ameliorate p-tau pathology by isomerizing p-tau, facilitating its trans-specific dephosphorylation and restoring its ability to bind to and restabilize microtubules and thence cytoskeletal integrity. Here, we report a novel localization of high levels of Pin1 with lipofuscin in aging neurons. This association could progressively drain available Pin1 and be deleterious to neuronal function during aging. We also show that Pin1 associates with lipofuscin when lipofuscin accumulations become marked and correlate with susceptibility to neurodegenerative disease. Our data are consistent with the possibility that neuronal Pin1 deficits may be a contributory factor in neurodegeneration associated with aging.

Expression of hyaluronan synthases and hyaluronidases in the MG63 osteoblast cell line.

The expression of hyaluronan synthases (1, 2 and 3) and hyaluronidases (1, 2, 3, 4 and PH20) was examined in the MG63 osteoblast cell line induced to mineralize in vitro and compared to the rate of glycosaminoglycan production. Real-time PCR analysis demonstrated a 13-fold decrease in hyaluronan synthase 3 expression in mineralising MG63 cells; no significant change in hyaluronan synthase 2 expression in mineralising cells and hyaluronan synthase 1 was not expressed. In mineralising MG63 cells a 62-fold increase in hyaluronidase 2, a 13-fold increase in hyaluronidase 3, and a 3-fold increase in hyaluronidase 4 expression were observed when compared to non-mineralising cells; hyaluronidase 1 and PH20 expression was not detected. After 5 weeks in mineralising culture conditions a 2-fold increase in total 3H-glucosamine incorporation was observed in cells when compared to 24 h or 5 week control cultures. This was made up of a 5-fold decrease in hyaluronan production, a 2-fold increase in chondroitin sulphate/dermatan sulphate and a 10-fold increase in 3H-glucosamine incorporation into the non-glycosaminoglycan fraction. A 3-fold increase in 35SO4 incorporation into chondroitin sulphate/dermatan sulphate was also observed. Thus there is co-ordinate expression of genes that control hyaluronan metabolism such that there is a general decrease in the expression of hyaluronan synthases, an increase in the expression of hyaluronidases and a corresponding decrease in hyaluronan production by mineralising MG63 cells.

Focally elevated creatine detected in amyloid precursor protein (APP) transgenic mice and Alzheimer disease brain tissue.

The creatine/phosphocreatine system, regulated by creatine kinase, plays an important role in maintaining energy balance in the brain. Energy metabolism and the function of creatine kinase are known to be affected in Alzheimer diseased brain and in cells exposed to the beta-amyloid peptide. We used infrared microspectroscopy to examine hippocampal, cortical, and caudal tissue from 21-89-week-old transgenic mice expressing doubly mutant (K670N/M671L and V717F) amyloid precursor protein and displaying robust pathology from an early age. Microcrystalline deposits of creatine, suggestive of perturbed energetic status, were detected by infrared microspectroscopy in all animals with advanced plaque pathology. Relatively large creatine deposits were also found in hippocampal sections from post-mortem Alzheimer diseased human brain, compared with hippocampus from non-demented brain. We therefore speculate that this molecule is a marker of the disease process.