Rheo-optical fourier transform infrared spectroscopy of polyurethanes and their blends with polyolefins

Rheo-optical Fourier transform infrared spectroscopy was used to analyze the orientational behavior of hard and soft segments of thermoplastic poly(ether urethane)s (TPU-Et) and poly(ester urethane)s (TPU-Es) and their blends with a 20 mass-% contribution of either polyethylene (PE) or polypropylene with an amorphous rubber phase (PP). The blends show a reduced stress level, lower elongation-to-break and a lower degree of orientation of the segments — especially for the TPU-Es blends — compared to those of pure TPU's when uniaxially elongated. Blends of TPU-Et with PP show reduced stress but increased strain compared to pure films of TPU-Et. This is caused by an improved adhesion of the rubber phase in the polypropylene and the polyether phase of TPU-Et. Optical micrographs visualize deformed polyolefin particles in elongated films of TPU-Et/PP blends. In the TPU-Et/PP blend we could achieve equivalent orientation for the polyolefin phase and the segments of TPU-Et caused by this higher phase adhesion compared to the other blends. Orientation functions (OF's) of absorption bands which specifically represent hard or soft polyurethane segments or which are characteristic of the polyolefin phase have been calculated to monitor the molecular alignment due to the mechanical treatment.     

Milk consumption in older Americans.

OBJECTIVES: The purpose of this study was to identify individual characteristics associated with types and frequency of milk consumption in older American adults. METHODS: A national probability-based sample (response rate = 91%) completed a telephone survey. Generalized logit and cumulative logit analyses were used to identify predictors of and barriers to fluid milk consumption in 494 elderly people. RESULTS: The likelihood of drinking skim or 1% milk rather than whole milk increased with nutrition knowledge, income, trying to reduce cholesterol intake, and being female (P < .05). Frequency of milk consumption was higher with nutrition knowledge, frequency of milk consumption during adolescence, and following a diabetic diet but was lower with milk intolerance. CONCLUSIONS: The present results could be used to develop intervention strategies for improving milk consumption rates among older adults. These strategies might focus on increasing elderly people's awareness of milk intolerance and lactose-reduced milk products and their concern about cholesterol. The relationship between current and adolescent milk consumption suggests that intervention strategies should begin early in life.     

Stimulation of protein phosphatase activity by insulin and growth factors in 3T3 cells.

Incubation of Swiss mouse 3T3-D1 cells with physiological concentrations of insulin resulted in a rapid and transient activation of protein phosphatase activity as measured by using [32P]phosphorylase a as substrate. Activation reached a maximum level (140% of control value) within 5 min of addition and returned to control levels within 20 min. The effect of insulin was dose-dependent with half-maximal activation occurring at approximately 5 nM insulin. This activity could be completely inhibited by addition of the heat-stable protein inhibitor 2, which suggests the presence of an activated type-1 phosphatase. Similar effects on phosphatase activity were seen when epidermal growth factor and platelet-derived growth factor were tested. These results suggest that some of the intracellular effects caused by insulin and growth factors are mediated through the activation of a protein phosphatase.     

Biodistribution and pharmacokinetics of the alphavbeta3-selective tracer 18F-galacto-RGD in cancer patients.

(18)F-Galacto-RGD has been developed for PET of alpha(v)beta(3) integrin expression, a receptor involved in, for example, angiogenesis and metastasis. Our aim was to study the kinetics and biodistribution of (18)F-Galacto-RGD in cancer patients. METHODS: Nineteen patients with metastases of malignant melanoma (n = 7), sarcomas (n = 10), or osseous metastases (n = 2) were examined. After injection of 133-200 MBq (18)F-Galacto-RGD, 3 consecutive emission scans from the pelvis to the thorax or dynamic emission scans of the tumor over 60 min, followed by 1 static emission scan of the body, were acquired. Time-activity curves and standardized uptake values (SUVs) were derived by image region-of-interest analysis with image-based arterial input functions. Compartmental modeling was used to derive the distribution volume for muscle tissue and tumors. RESULTS: (18)F-Galacto-RGD showed rapid blood clearance and primarily renal excretion. SUVs in tumors ranged from 1.2 to 9.0. Tumor-to-blood and tumor-to-muscle ratios increased over time, with peak ratios of 3.1 +/- 2.0 and 7.7 +/- 4.3, respectively, at 72 min. The tumor kinetics were consistent with a 2-tissue compartment model with reversible specific binding. Distribution volume values were, on average, 4 times higher for tumor tissue (1.5 +/- 0.8) than those for muscle tissue (0.4 +/- 0.1). The data suggest that there was only minimal free and bound (specific or nonspecific) tracer in muscle tissue. CONCLUSION: (18)F-Galacto-RGD demonstrates a highly favorable biodistribution in humans with specific receptor binding. Most important, this study shows that (18)F-Galacto-RGD allows visualization of alpha(v)beta(3) expression in tumors with high contrast. Consequently, this tracer offers a new strategy for noninvasive monitoring of molecular processes and may supply helpful information for planning and controlling of therapeutic approaches targeting the alpha(v)beta(3) integrin.     

Expression profiling identifies the CRH/CRH-R1 system as a modulator of neurovascular gene activity.

Corticotropin-releasing hormone receptor type 1 (CRH-R1)-deficient mice display reduced anxiety-like behavior, a chronic corticosterone deficit, and an impaired neuroendocrine stress response caused by disruption of the hypothalamic-pituitary-adrenocortical (HPA) axis. The molecular substrates and pathways of CRH/CRH-R1-dependent signaling mechanisms underlying the behavioral phenotype as well as the consequences of lifelong glucocorticoid deficit remain largely obscure. To dissect involved neuronal circuitries, we performed comparative expression profiling of brains of CRH-R1 mutant and wild-type mice using our custom made MPIP (Max Planck Institute of Psychiatry) 17k cDNA microarray. Microarray analysis yielded 107 genes showing altered expression levels when comparing CRH-R1 knockout mice with wild-type littermates. A significant proportion of differentially expressed genes was related to control of HPA and hypothalamic-pituitary-thyroid (HPT) axes reflecting not only the disturbance of the HPA axis in CRH-R1 mutant mice but also the interplay of both neuroendocrine systems. The spatial analysis of regulated genes revealed a prevalence for genes expressed in the cerebral microvasculature. This phenotype was confirmed by the successful cross-validation of regulated genes in CRH overexpressing mice. Analysis of the cerebral vasculature of CRH-R1 mutant and CRH overexpressing mice revealed alterations of functional rather than structural properties. A direct role of the CRH/CRH-R1 system was supported by demonstrating Crhr1 expression in the adult murine cerebral vasculature. In conclusion, these data suggest a novel, previously unknown role of the CRH/CRH-R1 system in modulating neurovascular gene expression and function.