Whole sheep ovary cryopreservation: evaluation of a slow freezing protocol with dimethylsulphoxide

Purpose  

To evaluate a slow freezing method for whole ovary cryopreservation by evaluating effects of added cryoprotectant.     

Accuracy of low-dose chest CT in intensive care patients

In this prospective study, we set out to determine the accuracy of low-dose computerized tomography (LDCT) of the chest in intensive care patients. Fifteen adult intensive care patients were examined with a standard-dose CT protocol (average radiation dose?=?6.7?mSv), chosen as the reference standard, followed by a non-contrast-enhanced LDCT protocol (average radiation dose?=?0.59?mSv). Each examination was then read by two separate groups of radiologists blinded to both the purpose and the protocol of the study. In the small group examined, the results showed 100% accuracy in the diagnosis of pneumomediastinum, pericardial effusion, and pleural effusion, and 90% accuracy in the diagnosis of pneumothorax and consolidation. There were no false-positive findings, and the few false-negative findings were unlikely to lead to any clinical interventions. Our examination protocol, while providing a tenfold reduction of the radiation dose, nevertheless remained accurate enough for resolving certain clinical questions common in the intensive care patient. Thus, we suggest that protocols aimed at reducing the radiation dose in chest CT could be applied to the intensive care patient for resolving some specific questions, without compromising the diagnostic yield of the examinations.     

Cancellous bone formation response to simulated resistance training during disuse is blunted by concurrent alendronate treatment

The purpose of this study was to assess the effectiveness of simulated resistance training (SRT) exercise combined with alendronate (ALEN) in mitigating or preventing disuse‐associated losses in cancellous bone microarchitecture and formation. Sixty male Sprague‐Dawley rats (6 months old) were randomly assigned to either cage control (CC), hind limb unloading (HU), HU plus either ALEN (HU + ALEN), SRT (HU + SRT), or a combination of ALEN and SRT (HU + SRT/ALEN) for 28 days. HU + SRT and HU + SRT/ALEN rats were anesthetized and subjected to muscle contractions once every 3 days during HU (four sets of five repetitions, 1000 ms isometric + 1000 ms eccentric). Additionally, HU + ALEN and HU + SRT/ALEN rats received 10 µg/kg of body weight of ALEN three times per week. HU reduced cancellous bone‐formation rate (BFR) by 80%, with no effect of ALEN treatment (?85% versus CC). SRT during HU significantly increased cancellous BFR by 123% versus CC, whereas HU + SRT/ALEN inhibited the anabolic effect of SRT (?70% versus HU + SRT). SRT increased bone volume and trabecular thickness by 19% and 9%, respectively, compared with CC. Additionally, osteoid surface (OS/BS) was significantly greater in HU + SRT rats versus CC (+32%). Adding ALEN to SRT during HU reduced Oc.S/BS (?75%), Ob.S/BS (?72%), OS/BS (?61%), and serum TRACP5b (?36%) versus CC. SRT and ALEN each independently suppressed a nearly twofold increase in adipocyte number evidenced with HU and inhibited increases in osteocyte apoptosis. These results demonstrate the anabolic effect of a low volume of high‐intensity muscle contractions during disuse and suggest that both bone resorption and bone formation are suppressed when SRT is combined with bisphosphonate treatment. © 2011 American Society for Bone and Mineral Research     

Nonlinear structured-illumination microscopy with a photoswitchable protein reveals cellular structures at 50-nm resolution

Using ultralow light intensities that are well suited for investigating biological samples, we demonstrate whole-cell superresolution imaging by nonlinear structured-illumination microscopy. Structured-illumination microscopy can increase the spatial resolution of a wide-field light microscope by a factor of two, with greater resolution extension possible if the emission rate of the sample responds nonlinearly to the illumination intensity. Saturating the fluorophore excited state is one such nonlinear response, and a realization of this idea, saturated structured-illumination microscopy, has achieved approximately 50-nm resolution on dye-filled polystyrene beads. Unfortunately, because saturation requires extremely high light intensities that are likely to accelerate photobleaching and damage even fixed tissue, this implementation is of limited use for studying biological samples. Here, reversible photoswitching of a fluorescent protein provides the required nonlinearity at light intensities six orders of magnitude lower than those needed for saturation. We experimentally demonstrate approximately 40-nm resolution on purified microtubules labeled with the fluorescent photoswitchable protein Dronpa, and we visualize cellular structures by imaging the mammalian nuclear pore and actin cytoskeleton. As a result, nonlinear structured-illumination microscopy is now a biologically compatible superresolution imaging method.     

Preservation of Red Blood Cells: Studies of Erythrocyte Adenine Nucleotides Using Luminescence Analysis

The levels of ATP and total adenine nucleotides (ATP + ADP + AMP) were determined by firefly luciferase assay in red blood cells during storage for 5 weeks at 4 degrees C. With few exceptions, no significant differences in nucleotide levels were found between whole blood stored in CPD-adenine and various preparations of red blood cells in CPD-adenine or CPD with saline-adenine-glucose (SAG) as additive. The levels of ATP and total adenine nucleotides during storage are discussed in relation to glucose levels, extracellular pH and shelf life of the red blood cells.