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Vascular endothelial growth factor A (VEGF-A) is a promoter of neovascularization and thus a popular therapeutic target for diseases involving excessive growth of blood vessels. In this study, we explored the potential of the disaccharide sucrose octasulfate (SOS) to alter VEGF165 diffusion through Descemet's membrane. Descemet's membranes were isolated from bovine eyes and used as a barrier between two chambers of a diffusion apparatus to measure VEGF transport. Diffusion studies revealed a dramatic increase in VEGF165 transport in the presence of SOS, with little diffusion of VEGF165 across the membrane over a 10-h time course in the absence of SOS. Diffusion studies with VEGF121, a non-heparin binding variant of VEGF, showed robust diffusion with or without SOS. To determine a possible mechanism, we measured the ability of SOS to inhibit VEGF interactions with extracellular matrix (ECM), using cell-free and cell surface binding assays. Binding studies showed SOS had no effect on VEGF165 binding to either heparin-coated plates or endothelial cell surfaces at less than mg/ml concentrations. In contrast, we show that SOS inhibited VEGF165 binding to fibronectin in a dose dependent manner and dramatically accelerated the rate of release of VEGF165 from fibronectin. SOS also inhibited the binding of VEGF165 to fibronectin-rich ECM deposited by vascular smooth muscle cells. These results suggest that fibronectin-rich extracellular matrices serve as barriers to VEGF165 diffusion by providing a network of binding sites that can trap and sequester the protein. Since the content of Descemet's membrane is typical of many basement membranes it is possible that they serve throughout the body as formidable barriers to VEGF165 diffusion and tightly regulate its bioavailability and distribution within tissues., (Copyright © 2012 Wiley Periodicals, Inc.)

Background: The literature is unclear as to the frequency and degree of vascular involvement among the various types of cardiac amyloidosis, specifically the senile type., Methods: We analyzed the intramyocardial vascular involvement, both qualitatively and quantitatively, in 18 patients with autopsy-proven cardiac amyloidosis [11 with primary amyloidosis (AL) and 7 with senile systemic amyloidosis (SSA)]., Results: AL patients (10/11) showed focally transmural vascular involvement by amyloid with thickening of the wall and impingement on the lumens. In SSA patients (6/7), the amyloid deposition was concentrated largely in the adventitia and external media. Histomorphometric analysis revealed that all patients with AL, SSA, and heart failure without amyloidosis had greater luminal areas than normal controls. In addition, the median of the ratio of subendocardial to subepicardial vascular luminal areas was 0.59 in AL patients, 1.17 in SSA patients, 0.94 in heart failure without amyloidosis patients, and 0.89 in normal controls (P=.034)., Conclusions: This study shows that the degree of vascular involvement and wall thickening with subsequent impingement on the lumen is much greater in AL than in SSA. All patients with heart failure, with and without amyloidosis, displayed greater luminal areas than normal controls. Moreover, a twofold dilatation of the vessels in the subepicardium compared to those in the subendocardium was noted only in patients with AL. This may be due to transmural vascular involvement by amyloid in these patients, which concomitantly decreases the transmural ventricular perfusion pressure, leading to compensatory expansion of the subepicardial vessels.

The first nuclear explosion test, named the Trinity test, was conducted on July 16, 1945 near Alamogordo, New Mexico. In the tremendous heat of the explosion, the radioactive debris fused with the local soil into a glassy material named Trinitite. Selected Trinitite samples from ground zero (GZ) of the test site were investigated in detail for radioactivity. The techniques used included alpha spectrometry, high-efficiency gamma-ray spectrometry, and low-background beta counting, following the radiochemistry for selected radionuclides. Specific activities were determined for fission products (90Sr, 137Cs), activation products (60Co, 133Ba, 152Eu, 154Eu, 238Pu, 241Pu), and the remnants of the nuclear fuel (239Pu, 240Pu). Additionally, specific activities of three natural radionuclides (40K, 232Th, 238U) and their progeny were measured. The determined specific activities of radionuclides and their relationships are interpreted in the context of the fission process, chemical behavior of the elements, as well as the nuclear explosion phenomenology.

Gross-beta activities have been determined weekly for 22 y from filtered atmospheric aerosols at seven sites in New York State. The activities, ranging from 0.1 to 0.9 mBq m(-3), varied seasonally and were evaluated in terms of meteorological factors. Cosmogenic beryllium (7Be) concentrations were determined quarterly on the air filters and weekly in deposition collected at one site. Over 98% of the air filters contained observable activity concentrations of 7Be (mean of 3 mBq m(-3)) and 210Pb (mean of 1 mBq m(-3)). However, only 20% of deposition samples contained Be concentrations above analytical detection limits. Tritium (3H) concentrations were below detection limits in deposition samples at the background site, but were present on most samples collected near a H-processing facility. Measurements of 131I were conducted weekly on charcoal canisters, with only one site showing observable concentrations (mean of 1 mBq m(-3)), due to nearby incineration of dried municipal sludge containing patient waste from hospital treatments.

A project to characterize the radionuclide and chemical components in natural spring waters in the vicinity of Saratoga Springs, New York (USA) has been completed. As a result of the measured radionuclide and chemical content, eight springs were labeled as mineral waters, whereas three springs contained very low concentrations of these components. The mineral waters were highly enriched in alkaline and alkaline-earth elements, as well as chloride ions. Three isotopes of radium ((224)Ra, (226)Ra, (228)Ra) were detected in the mineral waters and reached concentrations of 1, 20, and 2 Bq/L, respectively. Overall, the (226)Ra isotope constituted about 80% of the total radioactivity measured in the water samples. Dissolved uranium concentrations in the mineral waters were very low (mean approximately 50 mBq/L).

Gross alpha counting of evaporated water residues offers a simple method for screening alpha radioactivity in water for both public health and emergency purposes. The evaporation process for water has been improved by using a combination of roughening of the surface of counting planchettes, two-stage evaporation, and temperature-controlled block heating. The efficiency of the gas-proportional detector for alpha-particle detection in water residues was studied as a function of sample mass-thickness in the range between 0.1 and 13 mg cm(-2). The effect of alpha energy on the efficiency, as well as moisture absorption on the samples, were studied using (230)Th, (238)U, (239)Pu, (241)Am, and (244)Cm radionuclides. Also, alpha-to-beta crosstalk was investigated as a function of sample mass for (230)Th, (238)U, (239)Pu, (241)Am, and (244)Cm. The improved method can also be applied for gross alpha detection in biological fluids.

Airborne asbestos concentrations have been reconstructed for the entire 20th century for the first time through a combination of paleolimnological methods, particle-separation techniques, and analytical transmission electron microscopy. Pb concentrations and respirable aerosol mass concentrations in air and sediments yielded collection efficiencies of approximately 3000 m3 of air per gram of lake sediment. Airborne concentrations of chrysotile, the most common type of asbestos, reconstructed from control lake sediments echoed chrysotile's usage during the 20th century, with the highest concentrations mid-century (approximately 0.1 fibers/cm3) and then decreasing in the last quarter century. Reconstructed airborne concentrations of anthophyllite asbestos, a byproduct of local talc mining and milling, increased from <0.004 to 0.022 fibers/cm3 from 1846 to 1967. These anthophyllite concentrations during the approximately 100-year period of talc mining correlated well (r2 = 0.80, p < 0.01) with annual production of local talc and were much higher (p = 0.004) than concurrent concentrations in a control lake located upwind of the mines and mills. All of the chrysotile and more than 70% of the anthophyllite asbestos fibers were too narrow to be detected by phase-contrast light microscopy, the method used to measure airborne fiber concentrations before approximately 1980.

Polymeric diphenylmethane di-isocyanate (PMDI) is a precursor or an intermediate in the manufacture of pure MDI and is used in many industrial applications. Potential health effects of diisocyanates are generally considered to include irritation and respiratory sensitization, dictating the need for low occupational hygiene standards and robust hygiene monitoring methods. A wide range of methods has been developed or adopted for this purpose but questions concerning their ability to accurately sample MDI aerosols in the occupational environment have often been raised. In order to provide such information, studies have been conducted to compare several MDI sampling systems: the Institute of Occupational Medicine (IOM) 25-mm open-faced inhalable dust sampler; the 13-mm Millipore Swinnex Cassette sampler; the 37-mm open-face Millipore cassette; the midget-impinger, the glass tube containing glass wool, and two direct reading paper tape monitors. The program was comprised of two phases, the first being a preliminary comparison of the collection efficiencies of the IOM, 13 mm and midget-impinger at a range of orientations to air flow, aerosol particle sizes, and sampling flow rates, using inert polyethylene glycol aerosols. The second phase compared all samplers operating according to each manufacturer's recommendations and sampling PMDI aerosols at a range of particle sizes and concentrations. All studies were conducted in a wind tunnel. All filter methods performed well in atmospheres containing small particles except impingers that required a filter backup. In general, the variability of all the samplers was high for larger particle size ranges. Direct reading monitors showed low efficiencies.

Development and performance of a low-background gamma-ray spectrometer are described. The spectrometer consists of a 131% efficient Ge detector in U-type configuration. The passive shielding consists of ultrapure lead of 6" thickness. A top muon guard is used as an active shielding. The spectrometer and shielding are positioned inside a steel room made of 6"-thick pre-World War II iron. The steel room is located underground with 33 m of water-equivalent overburden. The total integrated background rate in the energy range 50-2,700 keV was measured at 0.068 counts per second per 100 cm3 Ge volume. The spectrometer serves as a reference instrument for low-level and highly accurate environmental radioactivity measurements. One specific application of 228Ra determination in drinking water is described. With a 1 l water sample, 1-step chemical procedure, and 1,000 min counting time, a detection limit Ld = 20 mBq/l (0.55 pCi/l) was reached, which meets the EPA mandated limit of 1 pCi/l. Methods of upgrading the spectrometer as well as the predicted improvements in 228Ra detection, including direct counting of water without chemical processing, are discussed.

Pakistan is one of the few countries in Asia that continues to use only leaded-petrol as vehicular fuel. The concentration of Pb in its petrol reported in 1991 was the highest (1.5-2.0 g Pb L(-1)) of all produced by the various Asian countries and far exceeded the WHO's guideline of 0.15 g Pb L(-1). We have undertaken a study to trace and quantify this toxic element in the environs of Karachi. Pakistan's major metropolis, having more than 30% of the nation's total number of vehicles. In this article we report the Pb contents of petrol and diesel currently manufactured and marketed in the city. Samples of 'Regular' petrol collected in 1999 was found to contain 0.363 g Pb L(-1) (range: 0.335-0.390 g Pb L(-1)), a factor of 5 lower than that marketed prior to 1991. Its concentration in diesel fuel was much lower (0.017 g Pb L(-1)). Based on the available statistical data on the type and volume of vehicular traffic, we assessed that the current lead emission from vehicular traffic into the atmosphere is 391 metric tons a year, which is a factor of 2.7 lower than that estimated for 1989.

A simultaneous detection of gross alpha and beta radioactivity was studied using gas proportional counting. This measurement is a part of a method mandated by US Environmental Protection Agency to screen for alpha and beta radioactivity in drinking water. Responses of a gas proportional detector to alpha and beta particles from several radionuclides were determined in drop and electroplated geometries. It is shown that, while the alpha radioactivity can be measured accurately in the presence of beta radioactivity, the opposite is not typically true due to alpha-to-beta crosstalk. The crosstalk, originating from the emission of conversion and Auger electrons as well as x rays, is shown to be dependent primarily on the particular alpha-decay scheme while the dependence on alpha energy is small but negligible. It was measured at 28-35% for 241Am, 22-24% for 230Th, and 4.9-6.5% for 239Pu. For 210Po, the crosstalk of 1.2-1.6% was observed mostly due to energy retardation. A method of reducing the crosstalk to a <3% level is proposed by absorbing the atomic electrons in a 6.2 mg cm(-2) Al absorber, at the same time decreasing the beta efficiency by 16-31%.

A simple and rapid method has been developed for the determination of isotopic radium, based on gamma-ray spectrometry. (228)Ra and (224)Ra are assayed by measuring the intensities of the photo-peaks in the 0.94 and the 2.62 MeV regions of the gamma-spectrum. The interference in these measurements, arising from the presence of the (226)Ra(210)Pb chain in the sample, is obviated by the almost complete expulsion of (222)Rn from the system. The precision of the method is +/-2% and +/-3 % in the determination of (228)Ra and (224)Ra respectively, the absolute sensitivities being 2 and 0.5 nCi. The method has been applied to evaluate the distribution of these isotopes in the various products of the Indian Rare-Earths Factory, Alwaye.