Measurement of a Peak in the Cosmic Microwave Background Power Spectrum from the North American Test Flight of Boomerang.

We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0&fdg;3 to 5 degrees from the North American test flight of the Boomerang experiment. Boomerang is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a long-duration balloon flight. During a 6 hr test flight of a prototype system in 1997, we mapped more than 200 deg(2) at high Galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26&arcmin; and 16&farcm;5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 µK(CMB).

A Measurement of Omega from the North American Test Flight of Boomerang.

We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85

Platelet membrane vesicles reduced microvascular bleeding times in thrombocytopenic rabbits.

We investigated the possible role of platelet membrane vesicles on hemostatic function in vivo. Platelet membrane vesicles were prepared from rabbit platelets stored for up to 6 months at -65 degrees C and transfused into thrombocytopenic rabbits. Significant reductions in microvascular bleeding times were observed up to 24 hours after transfusion, with the greatest corrections at 4 hours. Measurements of factor V, factor VIII, fibrin degradation products, and fibrinogen in animals transfused with membrane ruled out intravascular coagulation and suggested a direct effect of platelet membrane vesicles at the bleeding sites. This conclusion was supported morphologically by identification of membrane vesicles in bleeding time lesions and radiologically by accumulation of 111In-labeled vesicles in lesions. Production of platelet membrane vesicles was simple, and freezing allowed long-term storage of a product capable of short-term hemostasis.

Histologic assessment of cathepsin D in osteoarthritic cartilage.

The lysosomal endopeptidase cathepsin D is the most abundant proteinase in chondrocytes. Its significance in the pathogenesis of cartilage matrix proteoglycan (PG) degradation in osteoarthritis (OA) is unclear. The extracellular localization of cathepsin D and its potential spatial relationship to areas of PG depletion has been studied in human femoral head OA cartilage. Enzyme was identified by indirect immunofluorescence using rabbit antisera developed against a highly purified cathepsin D preparation. PG distribution was assessed in parallel sections by safranin O staining. Specimens were selected to include regions of cartilage having minimal structural and cellular alterations, severe reduction in thickness, hypocellularity, multicellular chondrocyte clusters and varying degrees of PG loss. Cathepsin D was identified in chondrocytes. When overlying fibrous connective tissue pannus was present, extracellular enzyme was predominantly localized to the cartilage-pannus interface. Cathepsin D could not be demonstrated extracellularly in areas of cartilage that were partially or totally devoid of PG. Chondrocytes in damaged regions, particularly in the superficial and upper transitional zones showing diffuse hypercellularity and/or "brood" clusters, contained increased enzyme staining. Results fail to support a role for cathepsin D in extracellular matrix PG degradation. The potential significance of this enzyme in the pathogenesis of OA would appear relegated to intracellular catabolism. Its intracellular increase at pathologic sites is consistent with enhanced catabolic activity in such regions.

Automation of a fluorometric method for the determination of 2-deoxy-D-glucose.

A continuous-flow fluorometric procedure for the determination of 2-deoxy-D-glucose (2DG) is described. The method utilizes Technicon Autoanalyzer equipment and modules, and is based on the acid-catalyzed condensation of 3,5-diaminobenzoic acid with 2DG. The procedure permits analysis of 20 samples/h, is sensitive to concentrations of 2DG as low as 0.2 mg/100 ml, and requires sample volumes of only 0.25 ml. 2DG can be quantitatively measured in serum samples or tissue extracts without requiring deproteinization. Glucose does not interfere with the assay while 2-deoxy-D-ribose develops a fluorescence which is about 15% of that produced by the same amount of 2DG and is additive when both deoxy sugars are present together. The procedure is accurate, reproducible, and fast, and can be run continuously.

Correlates of maximal oxygen consumption during treadmill exercise.

According to the Balke treadmill protocol, 39 healthy male USAF volunteers were subjected to maximal exercise. The subjects as a group passed the anaerobic threshold by the end of exercise since average venous lactate concentrations increased from 11.2 +/- 1.6 mg% (95% confidence limits) to 93.0 +/- 8.5 mg% (95% confidence limits), and the average gas exchange ratio (R) at the end of the exercise was greater than unity (p less than 0.0005). Tests for correlations showed weak but statistically significant (p less than 0.05) relationships between change in venous lactic acid concentrations and R (r = 0.44) and maximal heart rate (r = 0.34). Maximal oxygen consumption was correlated with time of exercise (r = 0.70) and subject weight (r = 0.33). Subject age and initial plasma lactate concentrations were not significantly correlated with any other variables. Multiple linear regression yielded an equation for prediction of maximal oxygen consumption which included terms for time of exercise and subject weight. Although the multiple correlation coefficent (r = 0.75) was statistically significant (p less than 0.05), it was considered insufficient for accurate prediction of maximal oxygen consumption.

Serum myocardial enzymes after +Gz acceleration.

Circulating levels of lactate dehydrogenase, glutamate-oxaloacetate, glutamate-pyruvate transaminase, and creatine phosphokinase, as well as its isoenzymes, were measured to investigate the possibility of myocardial damage during acceleration to high +Gz. Serum samples were analyzed in 12 human volunteers before, 6 h after, and 24 h after several bouts of accleration to 6, 8, 9, and 10 G. No substantial elevations of enzyme activities were observed. However, multivariate analysis of variance and multiple comparisons of the data indicated a small but statistically significant (p less than 0.01) increase in creatine phosphokinase. The results were consistent with enhanced skeletal muscle cell permeability consequent to muscular exercise.