Confocal Raman spectroscopy is introduced as a noninvasive in vivo optical method to measure molecular concentration profiles in the skin. It is shown how it can be applied to determine the water concentration in the stratum corneum as a function of distance to the skin surface, with a depth resolution of 5 microm. The resulting in vivo concentration profiles are in qualitative and quantitative agreement with published data, obtained by in vitro X-ray microanalysis of skin samples. Semi-quantitative concentration profiles were determined for the major constituents of natural moisturizing factor (serine, glycine, pyrrolidone-5-carboxylic acid, arginine, ornithine, citrulline, alanine, histidine, urocanic acid) and for the sweat constituents lactate and urea. A detailed description is given of the signal analysis methodology that enables the extraction of this information from the skin Raman spectra. No other noninvasive in vivo method exists that enables an analysis of skin molecular composition as a function of distance to the skin surface with similar detail and spatial resolution. Therefore, it may be expected that in vivo confocal Raman spectroscopy will find many applications in basic and applied dermatologic research.

There is a high prevalence of chronic hyponatremia in the elderly, frequently owing to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Recent reports have shown that even mild hyponatremia is associated with impaired gait stability and increased falls. An increased risk of falls among elderly hyponatremic patients represents a risk factor for fractures, which would be further amplified if hyponatremia also contributed metabolically to bone loss. To evaluate this possibility, we studied a rat model of SIADH and analyzed data from the Third National Health and Nutrition Examination Survey (NHANES III). In rats, dual-energy X-ray absorptiometry (DXA) analysis of excised femurs established that hyponatremia for 3 months significantly reduced bone mineral density by approximately 30% compared with normonatremic control rats. Moreover, micro-computed tomography (µCT) and histomorphometric analyses indicated that hyponatremia markedly reduced both trabecular and cortical bone via increased bone resorption and decreased bone formation. Analysis of data from adults in NHANES III by linear regression models showed that mild hyponatremia is associated with increased odds of osteoporosis (T-score –2.5 or less) at the hip [odds ratio (OR) = 2.85; 95% confidence interval (CI) 1.03–7.86; p < .01]; all models were adjusted for age, sex, race, body mass index (BMI), physical activity, history of diuretic use, history of smoking, and serum 25-hydroxyvitamin D [25(OH)D] levels. Our results represent the first demonstration that chronic hyponatremia causes a substantial reduction of bone mass. Cross-sectional human data showing that hyponatremia is associated with significantly increased odds of osteoporosis are consistent with the experimental data in rodents. Our combined results suggest that bone quality should be assessed in all patients with chronic hyponatremia. © 2010 American Society for Bone and Mineral Research.

Understanding biochemical mechanisms and changes associated with disease conditions and, therefore, development of improved clinical treatments, is relying increasingly on various biochemical mapping and imaging techniques on tissue sections. However, it is essential to be able to ascertain whether the sampling used provides the full biochemical information relevant to the disease and is free from artefacts. A multi-modal micro-spectroscopic approach, including FTIR imaging and PIXE elemental mapping, has been used to study the molecular and elemental profile within cryofixed and formalin-fixed murine brain tissue sections. The results provide strong evidence that amino acids, carbohydrates, lipids, phosphates, proteins and ions, such as Cl(-) and K(+), leach from tissue sections into the aqueous fixative medium during formalin fixation of the sections. Large changes in the concentrations and distributions of most of these components are also observed by washing in PBS even for short periods. The most likely source of the chemical species lost during fixation is the extra-cellular and intra-cellular fluid of tissues. The results highlight that, at best, analysis of formalin-fixed tissues gives only part of the complete biochemical "picture" of a tissue sample. Further, this investigation has highlighted that significant lipid peroxidation/oxidation may occur during formalin fixation and that the use of standard histological fixation reagents can result in significant and differential metal contamination of different regions of tissue sections. While a consistent and reproducible fixation method may be suitable for diagnostic purposes, the findings of this study strongly question the use of formalin fixation prior to spectroscopic studies of the molecular and elemental composition of biological samples, if the primary purpose is mechanistic studies of disease pathogenesis.

This article describes an observer-based technique for assessing auditory capacities of infants from 3 to 12 months of age. This technique, referred to as the Observer-based Psychoacoustic Procedure (OPP), combines features of the Forced-choice Preferential Looking technique developed by Teller (1979) and of Visual Reinforcement Audiometry (Moore ; Thompson, & Thompson, 1975). The rationale behind the procedure and the specific techniques used in its application are detailed here. Psychometric functions and thresholds for pure-tone detection and frequency discrimination obtained with OPP are also presented. The results for 6-month-olds are compared with results from previous studies employing a visually reinforced head-turn procedure. 627

This study aimed to develop inhalable powders containing phages active against antibiotic-resistant Pseudomonas aeruginosa for pulmonary delivery. A Pseudomonas phage, PEV2, was spray dried into powder matrices comprising of trehalose (0–80%), mannitol (0–80%) and L-leucine (20%). The resulting powders were stored at various relative humidity (RH) conditions (0, 22 and 60% RH) at 4 °C. The phage stability and in vitro aerosol performance of the phage powders were examined at the time of production and after 1, 3 and 12 months storage. After spray drying, a total of 1.3 log titer reduction in phage was observed in the formulations containing 40%, 60% and 80% trehalose, whereas 2.4 and 5.1 log reductions were noted in the formulations containing 20% and no trehalose, respectively. No further reduction in titer occurred for powders stored at 0 and 22% RH even after 12 months, except the formulation containing no trehalose. The 60% RH storage condition had a destructive effect such that no viable phages were detected after 3 and 12 months. When aerosolised, the total lung doses for formulations containing 40%, 60% and 80% trehalose were similar (in the order of 105 pfu). The results demonstrated that spray drying is a suitable method to produce stable phage powders for pulmonary delivery. A powder matrix containing ≥ 40% trehalose provided good phage preservation and aerosol performances after storage at 0 and 22 % RH at 4 °C for 12 months.

Study Objectives: Reported daytime fatigue may be influenced by modifiable risk factors. We hypothesized that daytime fatigue is associated with less-favorable lifestyle factors, including high body mass index, higher intake of dietary fat, and limited physical activity. Design: Cross-sectional analysis. Setting: Population-based survey. Participants: Participants aged 20 to 59 years in the Third National Health and Nutrition Examination Survey. Interventions: None. Measurements and Results:We examined relationships between responses to the question, "Right now would you say you are feeling energetic, fresh, average, tired or exhausted?" and body mass index, waist circumference, leisure time physical activity, and macronutrient intake. Analyses included only people who reported getting their usual amount of sleep the night before the evaluation and controlled for age, sex, and ethnicity; 5.6%, 14.6%, 58.3%, 19.5%, and 2.0% reported that they felt "energetic," "fresh," "average," "tired," and "exhausted" respectively. There was a U-shaped association across the categories of fatigue for physical activity, body mass index, and waist circumference, with the healthiest lifestyle factors being associated with reporting feeling "fresh." Relative to the fresh group, average, tired and exhausted participants were 1.6, 1.9, and 3.8 times more likely to report insufficient physical activity, all statistically different from the fresh group. This pattern was also observed for body mass index and waist circumference and persisted after adjustment for covariates and exclusion of individuals with depression. Conclusions:In adults aged 20 to 59 years in the United States, selfreported fatigue is associated with higher body mass index, higher waist circumference, and a reduced likelihood of getting recommended levels of physical activity.

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OBJECTIVE -To define incidence and predictors of nontraumatic lower-extremity amputation (LEA) in a diverse cohort of American Indians with diabetes. RESEARCH DESIGN AND METHODS -The Strong HeartStudy is a study of cardiovascular disease and its risk factors in 13 American-Indian communities. Data on the presence/ absence of amputations were collected at each of three serial examinations (1989 -1992, 1993-1995, and 1997-1999) by direct examination of the lower extremity. The logistic regression model was used to quantify the relationship between risk of LEA and potential risk factors, including diabetes duration, HbA 1c , peripheral arterial disease, and renal function.RESULTS -Of the 1,974 individuals with diabetes and without prevalent LEA at baseline, 87 (4.4%) experienced an LEA during 8 years of follow-up, and a total of 157 anatomical sites were amputated among these individuals. Amputation of toes was most common, followed by belowthe-knee and above-the-knee amputations. Age-adjusted odds of LEA were higher among individuals with unfavorable combinations of risk factors, such as albuminuria and elevated HbA 1c . Multivariable modeling indicated that male sex, renal dysfunction, high ankle-brachial index, longer duration of diabetes, less than a high school education, increasing systolic blood pressure, and HbA 1c predicted LEA risk.CONCLUSIONS -The 8-year cumulative incidence of LEA in American Indians with diabetes is 4.4%, with marked differences in risk by sex, educational attainment, renal function, and glycemic control. Diabetes Care 27:1885-1891, 2004D ata from the baseline examination of the Strong Heart Study (SHS) show that lower-extremity amputation (LEA) due to diabetes was present in 3% of the cohort and 6.3% of individuals with diabetes (1), findings that are generally consistent with previous studies (2-4) in other American-Indian tribes.Rates of incident LEA have been reported for several American-Indian tribes (5-8). Previous studies have shown that hyperglycemia (5,6,9,10), duration of diabetes (5,6), male sex (2,5,6,10), and prevalent microvascular disease (5,6,10) contribute to LEA risk in American Indians.The purpose of this study is to define the incidence of first LEA due to diabetes in a diverse, population-based cohort of American Indians with diabetes. We hypothesized that among SHS participants with diabetes, increasing age, diabetes duration, glycemic control, smoking, peripheral arterial disease, renal dysfunction, and male sex would predict incident LEA and that combinations of risk factors, such as poor glycemic control and renal dysfunction, would interact to increase LEA risk. RESEARCH DESIGN AND METHODS -The SHS was initiated in 1988 to investigate cardiovascular disease and its risk factors in American Indians (11). The design, methods, and laboratory techniques of the SHS have been previously reported (12,13). The SHS cohort consists of 4,549 participants aged 45-74 years from 13 AmericanIndian communities in Oklahoma, the Dakotas, and Arizona who were seen at the basel...