Oxygen saturation levels in the well elderly: altitude makes a difference

1. A reduction in oxygenation indicated by a lower PO2 and O2 saturation is a normal part of aging, but a change in carbon dioxide level is considered to reflect pulmonary disease. 2. The oxygen saturations of the well elderly living at moderate altitude and those living at low altitude were at the lower limits of normal for their respective altitudes. 3. Well elderly living at moderate altitude had an oxygen saturation that was significantly lower than the oxygen saturation of the people living at sea level. 4. Because of the wide range of oxygen saturation levels that exist in normal individuals, it is important to evaluate changes in oxygen saturation against the person's own level.     

Organization of sensory input to the nociceptive‐specific cutaneous trunk muscle reflex in rat,an effective experimental system for examining nociception and plasticity

Detailed characterization of neural circuitries furthers our understanding of how nervous systems perform specific functions and allows the use of those systems to test hypotheses. We have characterized the sensory input to the cutaneous trunk muscle (CTM; also cutaneus trunci [rat] or cutaneus maximus [mouse]) reflex (CTMR), which manifests as a puckering of the dorsal thoracolumbar skin and is selectively driven by noxious stimuli. CTM electromyography and neurogram recordings in naïve rats revealed that CTMR responses were elicited by natural stimuli and electrical stimulation of all segments from C4 to L6, a much greater extent of segmental drive to the CTMR than previously described. Stimulation of some subcutaneous paraspinal tissue can also elicit this reflex. Using a selective neurotoxin, we also demonstrate differential drive of the CTMR by trkA‐expressing and nonexpressing small‐diameter afferents. These observations highlight aspects of the organization of the CTMR system that make it attractive for studies of nociception and anesthesiology and plasticity of primary afferents, motoneurons, and the propriospinal system. We use the CTMR system to demonstrate qualitatively and quantitatively that experimental pharmacological treatments can be compared with controls applied either to the contralateral side or to another segment, with the remaining segments providing controls for systemic or other treatment effects. These data indicate the potential for using the CTMR system as both an invasive and a noninvasive quantitative assessment tool providing improved statistical power and reduced animal use. J. Comp. Neurol. 522:1048–1071, 2014. © 2013 Wiley Periodicals, Inc.     

Optical scatter imaging detects mitochondrial swelling in living tissue slices

Mitochondrial swelling is observed in neuronal injury and is a key event in many pathways to cell death. Currently, there is no technique for directly measuring mitochondrial size changes within living tissue slices with a field of view of several millimeters. In this paper, we test our hypothesis that Mie light-scatter theory can be used to study mitochondrial swelling in living tissue sections. Using a unique dual-angle scatter ratio (DASR) optical imaging system previously demonstrated to be sensitive to latex particle size changes and N-methyl-D-aspartate (NMDA) treatment of hippocampal slices, we studied mitochondrial swelling induced by 500 microM NMDA treatment of hippocampal slices. We observed a strong (R(2) = 0.73) and significant (P < 0.000005) correlation between the electron microscopy-determined diameters of swollen, intact mitochondria and the DASR imaging. We examined the robustness of the technique by evaluating the correlation between the dual-angle scatter ratio and the diameter of the dendrites, observed to swell, in NMDA-treated slices and found no correlation (R(2) = 0.06). The advantage of DASR imaging over electron microscopy or other methods of studying mitochondrial swelling is the sensitivity of DASR imaging to mitochondrial swelling over a large field of view (>9 mm(2)) in an intact tissue slice. This novel technique may allow for the study of regional changes in mitochondrial swelling and recovery as sequential events within a single specimen. This technique will eventually be useful in studying the efficacy of stroke and other disease therapies targeting mitochondrial swelling.     

Breast-specific gamma imaging is a cost effective and efficacious imaging modality when compared with MRI

Background

Both MRI and breast-specific gamma imaging are tools for surgical planning in newly diagnosed breast cancer. Breast-specific gamma imaging (BSGI) is used less frequently although it is of similar utility and lower cost. We compared the diagnostic and cost efficacy of BSGI with MRI.

Methods

Retrospective review of 1,480 BSGIs was performed in a community breast health center, 539 had a new diagnosis of cancer, 75 patients having both MRI and BSGI performed within 2 months of each other. Institutional charges for BSGI ($850) and MRI ($3,381) were noted.

Results

BSGI had a sensitivity of 92%, specificity of 73%, positive predictive value of 78%, and negative predictive value of 90%. This compared favorably with MRI that had sensitivity of 89%, specificity 54%, positive predictive value 67%, and negative predictive value 83%. The accuracy of BSGI was higher at 82% vs MRI at 72%. Total cost of MRI imaging was $253,575 vs BSGI at $63,750.

Conclusions

BSGI is a cost-effective and accurate imaging study for further evaluation of dense breast tissue and new diagnosis of cancer.     

Intra‐ and inter‐centre standardisation of thromboelastography (TEG®)

Thromboelastography is used for assessment of coagulation and to guide administration of blood products peri‐operatively. There is currently no method of standardisation in the UK, nor an approved method of proving quality. We investigated the reproducibility of thromboelastography by testing whole blood with no coagulation abnormality in three phases. Where a single operator performed multiple assays on the same blood sample at a single location, we found considerable variation, with 21% of R‐ and 25% of K‐time measurements lying outside a set tolerance range (median ± 20%). Where samples were analysed by different operators in a single location, this finding was repeated. Where blood was transported in a citrated form for simultaneous analysis in multiple locations, results were more consistent, suggesting improved stability. Across all phases of testing there was good reproducibility of the maximum amplitude. Further examination of the results indicated less variation where analysis was performed on blood taken from the same kaolin vial compared with results from different vials. Our preliminary study indicates that R‐ and K‐times may be highly variable, which we hypothesise may be due to variable mixing of blood and kaolin. We intend to repeat this study in the context of coagulopathy, where variability in results could potentially impact upon transfusion practice.     

CT diagnosis of intestinal ascariasis

The clinical symptoms and appearance by computed tomography of intestinal ascariasis are described in a patient with unsuspected Ascaris lumbricoides infestation.