Grayscale Units Research Articles

Lung ultrasound in the critically ill

Lung ultrasound is a basic application of critical ultrasound, defined as a loop associating urgent diagnoses with immediate therapeutic decisions. It requires the mastery of ten signs: the bat sign (pleural line), lung sliding (yielding seashore sign), the A-line (horizontal artifact), the quad sign, and sinusoid sign indicating pleural effusion, the fractal, and tissue-like sign indicating lung consolidation, the B-line, and lung rockets indicating interstitial syndrome, abolished lung sliding with the stratosphere sign suggesting pneumothorax, and the lung point indicating pneumothorax. Two more signs, the lung pulse and the dynamic air bronchogram, are used to distinguish atelectasis from pneumonia. All of these disorders were assessed using CT as the “gold standard” with sensitivity and specificity ranging from 90% to 100%, allowing ultrasound to be considered as a reasonable bedside “gold standard” in the critically ill. The BLUE-protocol is a fast protocol (<3 minutes), which allows diagnosis of acute respiratory failure. It includes a venous analysis done in appropriate cases. Pulmonary edema, pulmonary embolism, pneumonia, chronic obstructive pulmonary disease, asthma, and pneumothorax yield specific profiles. Pulmonary edema, e.g., yields anterior lung rockets associated with lung sliding, making the “B-profile.” The FALLS-protocol adapts the BLUE-protocol to acute circulatory failure. It makes sequential search for obstructive, cardiogenic, hypovolemic, and distributive shock using simple real-time echocardiography (right ventricle dilatation, pericardial effusion), then lung ultrasound for assessing a direct parameter of clinical volemia: the apparition of B-lines, schematically, is considered as the endpoint for fluid therapy. Other aims of lung ultrasound are decreasing medical irradiation: the LUCIFLR program (most CTs in ARDS or trauma can be postponed), a use in traumatology, intensive care unit, neonates (the signs are the same than in adults), many disciplines (pulmonology, cardiology…), austere countries, and a help in any procedure (thoracentesis). A 1992, cost-effective gray-scale unit, without Doppler, and a microconvex probe are efficient. Lung ultrasound is a holistic discipline for many reasons (e.g., one probe, perfect for the lung, is able to scan the whole-body). Its integration can provide a new definition of priorities. The BLUE-protocol and FALLS-protocol allow simplification of expert echocardiography, a clear advantage when correct cardiac windows are missing.

Hydrogen sulfide modulates sinusoidal constriction and contributes to hepatic micorcirculatory dysfunction during endotoxemia

Hydrogen sulfide (H₂S) affects vascular resistance; however, its effect on the hepatic microcirculation has not been investigated. Hepatic sinusoidal perfusion is dysregulated during sepsis, contributing to liver injury. Therefore, the present study determined the effect of H₂S on the hepatic microcirculation and the contribution of endogenous H₂S to hepatic microcirculatory dysfunction in an endotoxin model of sepsis. Portal infusion of H₂S increased portal pressure in vivo (6.8 ± 0.2 mmHg before H₂S vs. 8.6 ± 0.8 mmHg peak during H₂S infusion, P < 0.05). Using intravital microscopy, we observed decreased sinusoidal diameter (6.2 ± 0.27 μm before H₂S vs. 5.7 ± 0.3 μm after H₂S, P < 0.05) and increased sinusoidal heterogeneity during H₂S infusion (P < 0.05) and net constriction. Since hepatic H₂S levels are elevated during sepsis, we used the cystathionine γ lyase inhibitor DL-propargylglycine (PAG) to determine the contribution of H₂S to the hypersensitization of the sinusoid to the vasoconstrictor effect of endothelin-1 (ET-1). PAG treatment significantly attenuated the sinusoidal sensitization to ET-1 in endotoxin-treated animals. ET-1 infusion increased portal pressure to 175% of baseline in endotoxemic animals, which was reduced to 143% following PAG treatment (P < 0.05). PAG abrogated the increase in sinusoidal constriction after ET-1 infusion in LPS-treated rats (30.9% reduction in LPS rats vs. 11.6% in PAG/LPS rats, P < 0.05). Moreover, PAG treatment significantly attenuated the increase in NADH fluorescence following ET-1 exposure during endotoxemia (61 grayscale units LPS vs. 21 units in PAG/LPS, P < 0.05), suggesting an improvement in hepatic oxygen availability. This study is the first to demonstrate a vasoconstrictor action of H₂S on the hepatic sinusoid and provides a possible mechanism for the protective effect of PAG treatment during sepsis.

Abstract 19756: Association of Increased PTEN-Induced Putative Kinase 1 (PINK1) Expression and Oxidative Damage in Gastrocnemius Myofibers of Patients with Peripheral Arterial Disease

Introduction: Oxidative damage (OxD) determined as protein adducts of 4-hydroxy-2-nonenal (HNE) is increased in gastrocnemius myofibers of patients with peripheral arterial disease (PAD) and correlates with disease progression. Mitochondria in PAD gastrocnemius exhibit structural damage and respiratory dysfunction; however, the extent of mitochondrial damage and its relationship to OxD have not been determined. PINK1 is a glycoprotein normally expressed in low abundance on the mitochondrial external membrane. Mitochondrial damage signaled as loss of ion potential across the external membrane produces a marked increase in PINK1, which initiates mitophagy. In this study, we tested the hypothesis that mitochondrial damage is 1) prevalent among gastrocnemius myofibers of PAD patients and 2) linked to OxD. Methods: Gastrocnemius biopsies were collected from five PAD patients with claudication and five controls matched on the basis of age, gender, smoking history and type II diabetes. Biopsy specimens were fixed in methacarn, embedded in paraffin, sectioned and mounted to glass slides. Fluorescence labeled PINK1 protein and HNE adducts in individual myofibers, were quantified by quantitative fluorescence microscopy and expressed as mean pixel intensity in gray scale units (gsu) corrected for background. Results: PINK1 protein expression was increased (p=0.008) in PAD (mean ± S.E.M.; 494.78 ± 0.02 gsu) compared to control myofibers (102.45 ± 0.02 gsu) of the gastrocnemius. PINK1 was increased in 93% of the PAD myofibers. The association of increased (greater than two standard deviations above the control means) PINK1 expression and HNE adducts was determined for PAD myofibers. HNE adducts were increased in 67% of a random sample of PAD fibers expressing increased PINK1. Conclusions: Increased expression of PINK1 protein in the gastrocnemius myofibers of PAD patients with claudication, has established the presence of irreversible mitochondrial damage in a large proportion of myofibers. Elevation of OxD in 67% of PAD myofibers expressing increased PINK1 links OxD and mitochondrial damage. The data are consistent with a contribution of OxD to myofibers in PAD gastrocnemius, by damaged mitochondria.

Novel Single-Chain Antibody-Targeted Microbubbles for Molecular Ultrasound Imaging of Thrombosis

Background— Molecular imaging is a fast emerging technology allowing noninvasive detection of vascular pathologies. However, imaging modalities offering high resolution currently do not allow real-time imaging. We hypothesized that contrast-enhanced ultrasound with microbubbles (MBs) selectively targeted to activated platelets would offer high-resolution, real-time molecular imaging of evolving and dissolving arterial thrombi. Methods and Results— Lipid-shell based gas-filled MBs were conjugated to either a single-chain antibody specific for activated glycoprotein IIb/IIIa via binding to a Ligand-Induced Binding Site (LIBS-MBs) or a nonspecific single-chain antibody (control MBs). Successful conjugation was assessed in flow cytometry and immunofluorescence double staining. LIBS-MBs but not control MBs strongly adhered to both immobilized activated platelets and microthrombi under flow. Thrombi induced in carotid arteries of C57Bl6 mice in vivo by ferric chloride injury were then assessed with ultrasound before and 20 minutes after MB injection through the use of gray-scale area intensity measurement. Gray-scale units converted to decibels demonstrated a significant increase after LIBS-MB but not after control MB injection (9.55±1.7 versus 1.46±1.3 dB; P &lt;0.01). Furthermore, after thrombolysis with urokinase, LIBS-MB ultrasound imaging allows monitoring of the reduction of thrombus size ( P &lt;0.001). Conclusion— We demonstrate that glycoprotein IIb/IIIa–targeted MBs specifically bind to activated platelets in vitro and allow real-time molecular imaging of acute arterial thrombosis and monitoring of the success or failure of pharmacological thrombolysis in vivo.

Pregnancy amplifies the deleterious effects of nanoparticle exposure on microvascular nitric oxide: a role for oxidant stress

Exposure to environmental nanoparticles (NP) may pose a significant risk to cardiovascular health. In male rats, NP inhalation reduces systemic arteriolar endothelium‐dependent dilation due to scavenging of nitric oxide (NO) by reactive oxygen species (ROS). Since NO plays a key role in microvascular adaptations to pregnancy, we assessed the effect of pulmonary NP exposure on oxidant levels and NO‐dependent dilation in extrapulmonary arterioles of pregnant rats. Virgin (V) and mid‐pregnant (MP, Day 11–12) rats were exposed to TiO2 NP via intratracheal instillation (500 μg deposition). After 24 hours, spinotrapezius muscle arterioles were probed for ROS via ethidium bromide (EB) fluorescence or challenged with ACh before vs. after treatment with L‐NMMA, a NOS inhibitor. TiO2 exposure significantly increased arteriolar EB fluorescence in both groups, but this effect was greater in MP (grayscale units: shams =143±3, NP =172±6) than in V (shams= 160±3, NP =176±5). TiO2 also reduced the L‐NMMA‐sensitive component of ACh‐induced dilation, but to a greater extent in MP. These results suggest that the increase in arteriolar ROS and decrease in NO linked to NP exposure is exacerbated in pregnancy. Since NO contributes importantly to systemic vasodilation in pregnancy, this effect of NP could compromise blood pressure regulation in this setting. AHA 09GRNT2250298, NIH ES018274, ES015022.

Increased prevalence of simple renal cysts in patients with gout

The aim of this study was to determine the prevalence of simple renal cysts in gout patients and evaluate associated risk factors for its development. Hundred and forty-six patients followed at our outpatient Gout Unit and 47 sex- and age-matched healthy kidney donors who had undergone routine renal ultrasonography, using a static gray scale and real-time B-mode units with a 3.5- or 5.0-MHz transducer, were evaluated for the presence of renal cysts. Demographic and clinical characteristics of gout patients were evaluated considering possible risk factors for the occurrence of simple renal cysts such as age, male gender, hypertension, and renal impairment. The prevalence of simple renal cyst was 26.0 % in gout patients and 10.6 % in control group (P = 0.045). Gout patients with simple renal cysts presented less renal lithiasis than those without this complication (5.2 vs 25.9 %; P = 0.003) in spite of an overall higher frequency of renal stones in gout patients compared to control group (20.5 vs. 6.3 %, P = 0.025). The presence of simple renal cyst in gout was not associated with previously reported factors such as age (P = 0.296), male predominance (P = 0.688), hypertension (P = 0.314), and renal impairment (P = 254). Moreover, no association with disease duration (P = 0.843) or tophi (P = 0.616) was observed. In conclusion, gout patients have an increased prevalence of simple renal cysts associated with a lower occurrence of nephrolithiasis. Whether renal cysts have any protective effect in the development of nephrolithiasis in gout remains to be determined.

Backscattered light from the cornea before and after laser-assisted subepithelial keratectomy for myopia

To study corneal backscatter changes after laser-assisted subepithelial keratectomy (LASEK) and to search for correlations between the changes in forward and backward corneal light scatter. Antwerp University Hospital, Edegem, Belgium. Prospective interventional case series. Corneal backscatter was determined with a commercial Scheimpflug device and purpose-written image-analysis software. The mean backscatter profile and gray value distributions of the images for a 1.0 mm zone around the corneal apex were obtained preoperatively and 6 months after LASEK for myopia. This was compared with forward light scatter (or straylight) using measurements obtained with the compensation comparison method. The study enrolled 80 eyes (40 patients; mean age 34.2 years ± 10.4 [SD]). Very strong correlations were found between the backscatter profiles of right eyes and left eyes preoperatively. Hence, only right eyes were used for further calculations. The epithelial-Bowman peak of the backscatter profile decreased significantly after LASEK (mean decrease -2.2 ± 4.7 grayscale units) (P=.002, paired t test), which corresponded to the ablation of Bowman layer. Significant changes in the gray-value distribution were observed postoperatively, corresponding to the decreases in the epithelium-Bowman peak. Forward light scatter decreased significantly after LASEK (mean decrease -0.10 ± 0.13) (P<.001); however, no significant correlation with corneal backscatter was observed. The anterior part of the corneal backscatter profile decreased significantly after LASEK. A significant reduction in forward light scatter was also seen, although it was not correlated to backward light scatter.

Reversible data embedding for high quality images using interpolation and reference pixel distribution mechanism

This paper proposes a reversible data hiding method based on image interpolation and the detection of smooth and complex regions in the cover images. A binary image that represents the locations of reference pixels is constructed according the local image activity. In complex regions, more reference pixels are chosen and, thus, fewer pixels are used for embedding, which reduces the image degradation. On the other hand, in smooth regions, less reference pixels are chosen, which increases the embedding capacity without introducing significant distortion. Pixels are interpolated according to the constructed binary image, and the interpolation errors are then used to embed data through histogram shifting. The pixel values in the cover image are modified one grayscale unit at most to ensure that a high quality stego image can be produced. The experimental results show that the proposed method provides better image quality and embedding capacity compared with prior works.

Functional Interactions between Mldp (LSDP5) and Abhd5 in the Control of Intracellular Lipid Accumulation

Cellular lipid metabolism is regulated in part by protein-protein interactions near the surface of intracellular lipid droplets. This work investigated functional interactions between Abhd5, a protein activator of the lipase Atgl, and Mldp, a lipid droplet scaffold protein that is highly expressed in oxidative tissues. Abhd5 was highly targeted to individual lipid droplets containing Mldp in microdissected cardiac muscle fibers. Mldp bound Abhd5 in transfected fibroblasts and directed it to lipid droplets in proportion to Mldp concentration. Analysis of protein-protein interactions in situ demonstrated that the interaction of Abhd5 and Mldp occurs mainly, if not exclusively, on the surface of lipid droplets. Oleic acid treatment rapidly increased the interaction between Abhd5 and Mldp, and this effect was suppressed by pharmacological inhibition of triglyceride synthesis. The functional role of the Abhd5-Mldp interaction was explored using a mutant of mouse Abhd5 (E262K) that has greatly reduced binding to Mldp. Mldp promoted the subcellular colocalization and interaction of Atgl with wild type, but not mutant, Abhd5. This differential interaction was reflected in cellular assays of Atgl activity. In the absence of Mldp, wild type and mutant Abhd5 were equally effective in reducing lipid droplet formation. In contrast, mutant Abhd5 was unable to prevent lipid droplet accumulation in cells expressing Mldp despite considerable targeting of Atgl to lipid droplets containing Mldp. These results indicate that the interaction between Abhd5 and Mldp is dynamic and essential for regulating the activity of Atgl at lipid droplets containing Mldp.

Abstract 1065: A New Method for Stem Cell Imaging Using Contrast Ultrasound

Background : Mesenchymal stem cells (MSCs) are a promising new cardiac reparative therapy. The distribution of delivered MSCs is poorly understood due to limited methods to track them in vivo . To test the hypothesis that ultrasound can detect MSCs, gas-filled microbubbles (MBs) were developed for MSC uptake. Methods : Perfluorocarbon gas-filled MBs were synthesized from a biodegradable polymer. Cultured rat and human bone-marrow derived MSCs were dwelled with MBs (12 hrs), washed, and suspended in medium. MSC uptake of MBs and MB retention of gas were confirmed with transmission electron microscopy (TEM) and density centrifugation. Spectral analysis of free MB response to up to 10MHz ultrasound was performed. 2nd harmonic and contrast pulse sequence (CPS) 2D echo imaging (7MHz) of MB-labeled and unlabeled MSCs was performed at a mechanical index (MI) 0.3 and 1.9. Videointensity was measured in 200 frames/capture. Results: Frequency spectra of free MBs contained 2nd and 3rd harmonics, indicating MB non-linearity. TEM showed MBs within MSCs (Figure ). By density centrifugation, MSCs with MBs were less dense than MSCs alone, confirming intracellular MB gas retention. Videointensity (gray scale units) of MSCs containing MBs vs MSCs alone was higher at both low MI (35±2 vs 0±0 harmonic, p&lt;0.005; 21±2 vs 15±0 CPS, p&lt;0.005), and high MI (14±2 vs 6±1 harmonic, p&lt;0.005; 6±2 vs 0±0 CPS, p&lt;0.005). Conclusions : Our acoustically active polymer MBs are internalized by MSCs and render them detectable with ultrasound. Because the polymer degrades slowly, this approach may permit serial non-invasive in vivo ultrasound imaging of MSC fate, thus facilitating optimization of cell therapy strategies.

Gentamicin is Primarily Localized in Vestibular Type I Hair Cells after Intratympanic Administration

Intratympanic (IT) gentamicin injections are effective in the control of episodic vertigo due to Ménière's disease. Histological studies in animals have found that the loss of type I vestibular hair cells far exceeds that of type II cells after IT gentamicin treatment. The objective of this study was to determine whether this selective toxicity for type I hair cells might be due to selective concentration of the drug by these cells. Gentamicin was localized within the vestibular epithelium by both direct and indirect methods. Gentamicin conjugated to Texas Red(R) was used as a direct tracer, and anti-gentamicin antibody provided an indirect means of localization. Conjugated or unconjugated gentamicin was injected into the left tympanic space of chinchillas. The animals were killed and fixed 1 or 3 weeks post-treatment. Confocal fluorescence microscopy was used to determine the localization of gentamicin in semicircular canal cristae. Results from the animals killed within 1 week of administration showed that numerous type I hair cells still remained throughout the epithelium. The mean intensity in grayscale units (0-255) of anti-gentamicin labeling for type I hair cells was 28.14 (95% CI 24.60-31.69), for type II hair cells was 17.09 (14.99-19.20), and for support cells was 5.35 (5.34-5.46; p < 0.001, ANOVA). Anti-gentamicin antibody labeling appeared in the majority of type I hair cells throughout their cytoplasm, but with greater intensity at the apex (p < 0.001). Intensity of fluorescence with Texas-Red conjugated gentamicin was 25.38 (22.83-27.94) in type I hair cells, 15.60 (14.73-16.48) in type II cells, and 12.62 (12.06-13.17) in support cells (p < 0.001, ANOVA). These results suggest that type I hair cells are more susceptible to gentamicin because they more avidly take up or retain the drug in the early period after administration.

An investigation into the use of MR imaging to determine the functional cross sectional area of lumbar paraspinal muscles

The purpose of this study was to investigate the use of magnetic resonance (MR) imaging and image processing software to determine the functional cross-sectional area (FCSA) (the area of muscle isolated from fat) of the lumbar paraspinal muscles. The measurement of the morphology of the lumbar paraspinal muscles has become the focus of several recent investigations into the aetiology of low back pain. However, the reliability and validity of determining the FCSA of the lumbar paraspinal muscles using MR imaging are yet to be reported. T2 axial MR scans at the L1-S1 spinal levels of six subjects were obtained using identical MR systems and scanning parameters. Lean paraspinal muscle, vertebral body bone and intermuscular fat were manually segmented using image analysis software to assign a grey scale range to the MR signal intensity emitted by each tissue type. The resultant grey scale range for muscle was used to determine FCSA measurements for each of the paraspinal muscles, psoas, quadratus lumborum, erector spinae and lumbar multifidus on each scan slice. As various biological, instrument and measurement factors can affect MR signal intensity, a sensitivity analysis was conducted to determine the error associated in calculating FCSA for paraspinal muscle using a discrete grey scale range. Cross-sectional area and FCSA measurements were repeated three times and reliability indices for the FCSA measurements were obtained, showing excellent reliability, intra class correlation coefficient (mean=0.97, range 0.90-0.99) and %SEM (mean=2.6%, range 0.7-4.8%). In addition, the error associated with miscalculation of the grey scale range for the MR signal intensity of muscle was calculated and found to be low with an error of 20 grey scale units at the upper end of the muscle's grey scale range resulting in a very small error in the measured muscle FCSA. The method presented in this paper has a variety of practical applications in areas such as evidence-based rehabilitation, biomechanical modelling and the determination of segmental inertial parameters.

Endothelin 1 impairs oxygen delivery in livers from LPS-primed animals.

Endothelin 1 (ET-1) is a potent vasoactive peptide that acts at sinusoidal and extrasinusoidal sites in the liver. Sensitivity to ET-1 increases in LPS-primed animals and is associated with impaired liver microcirculation in these animals. We hypothesized that LPS priming leads to an exacerbation in the impaired oxygen delivery in response to intraportal infusion of ET-1. Rats were studied 24 h after LPS injection (1 mg/kg, i.p.). Surface PO2 was determined using a recently developed technology of O2 mapping. The baseline portal pressure was higher in LPS-primed animals (P < 0.05), and increased to'similar magnitude as sham animals after a 10-min infusion of ET-1. The resultant portal pressure remained elevated in LPS compared to sham animals. There was no significant difference in baseline mean arterial pressure, and no significant systemic response to ET-1 in either group. In contrast to the macrohemodynamic, the decrease in tissue surface PO2 in response to ET-1 infusion was potentiated by LPS treatment (increased from baseline levels 33.8+/-9 to 46.8+/-8.3 in sham; 42.3+/-9.1 to 69+/-6.5 gray scale units in LPS; P < 0.01, sham vs. LPS) at end of infusion of ET-1 for 10 min. This indicates tissue hypoxia in response to ET-1, which is exacerbated in livers from LPS-primed animals compared to sham. Frequency distribution analysis showed a shift in mode from lower intensity (higher PO2) to areas with higher fluorescent intensity ranges (lower PO2), indicating areas with shut down in perfusion in LPS-treated animals. In the whole liver, ET-1 suppressed oxygen consumption, and this response was potentiated by LPS pretreatment. We propose that ET-1 impairs oxygen delivery in the liver during endotoxemia, resulting in areas of focal hypoxia. This response is possibly due to potentiated action of ET-1 at both sinusoidal and extrasinusoidal sites in the liver during endotoxemia.

Real-time myocardial blood flow imaging in normal human beings with the use of myocardial contrast echocardiography

Triggered myocardial contrast echocardiography (MCE) has been used successfully to quantify myocardial blood flow and assess coronary stenosis in animal models, but practical considerations have limited its broad clinical use. Real-time MCE may have practical advantages to assess perfusion and real time myocardial blood flow in human beings. We compared real-time MCE with triggered imaging in 23 normal human volunteers by using an investigational ultrasound contrast agent (DMP-115) and a commercially available ultrasound platform (Acuson Sequoia). Peak myocardial opacification (reflecting myocardial blood volume) after contrast infusion was quantified digitally in gray scale units (GU). In 13 subjects, myocardial blood flow reserve was assessed during dipyridamole infusion with the use of intermittent destruction-replenishment techniques. Real-time MCE resulted in a 30- to 45-GU increase from baseline compared with a 20- to 70-GU increase with triggered imaging. Real-time MCE showed no statistical difference in opacification ( P = .131 by analysis of variance) among any of the myocardial regions of interest. Triggered imaging resulted in heterogeneous opacification among the regions of interest ( P < .05 by analysis of variance). Dipyridamole did not significantly change peak myocardial opacification (myocardial blood volume) for either technique. Quantification of flow reserve revealed that myocardial blood flow reserve for the dipyridamole group was 3.6 ± 0.4 (mean ± 1 standard error of the mean). Real-time MCE is feasible in normal human volunteers and provides homogenous opacification of the myocardium. Furthermore, quantification of myocardial blood flow with real-time MCE in normal human beings produces results that are consistent with the known physiology of the coronary microcirculation. (J Am Soc Echocardiogr 2001;14:698-705.)

Comparison of the performance of zeolite‐containing and phosphate‐containing ECE reference detergents in three different wash fastness tests

This paper describes a study of the wash fastness of a number of dyed cotton and nylon substrates in the C06/C2S, C08/C2S and M&amp;S C4A (60 °C) wash fastness tests, using both zeolite‐ and phosphate‐containing detergent formulations. The staining of adjacents was generally shown to be at least 0.5 grey scale units less in all three tests when the zeolite‐containing standard detergent formulation was used. Staining in the C06/C2S test was usually 0.5 grey scale units higher than in the corresponding C08 and M&amp;S C4A test because of the lower liquor ratio at which the former test was conducted. It is therefore recommended that, if the C08 test is to set demanding levels of colour fastness, the liquor ratio at which it is conducted should be reduced to ca. 30:1.

Increased Epidermal Growth Factor Receptor Expression in Rat Aorta in Deoxycorticosterone Acetate-Salt Induced Hypertension/ATL&gt;

79 Receptors and signal transduction Epidermal growth factor (EGF) causes contraction in arteries from Deoxycorticosterone Acetate-Salt (DOCA) hypertensive rats but not in normotensive sham rats. We hypothesized that an increase in the number of EGF receptors (EGFR) in arteries from DOCA-salt rats enables the observed contraction to EGF to occur. All DOCA-salt rats had a systolic blood pressure (SBP) &gt; 170 mm Hg, while all sham rats had a SBP &lt; 135 mm Hg. Thoracic aorta were removed for measurement of isometric force, EGFR mRNA levels, and EGFR protein levels. EGF caused a significant contraction in endothelium-denuded aorta from DOCA-salt rats [(35 +/- 3% of maximal phenylephrine (PE, 10uM)-induced contraction)] as compared to aorta from sham rats (4+/-2%). EGFR tyrosine kinase specific inhibitors, 4,5-Dianilinophthalimide (10uM) and AG1478 (250 nM), reduced the contraction in aorta from DOCA-salt rats by 85 +/- 14% and 65+/- 10% respectively. The mRNA for EGFR in DOCA-salt aorta was increased 4.2 fold as compared to sham aorta. EGFR protein levels were examined using immunohistochemistry where specific binding was defined as binding which was quenched by a 10x concentration of neutralizing peptide. In 7 of 8 quantitative comparisons between aorta from DOCA-salt and sham rats, DOCA-salt aorta sections demonstrated greater specific binding than in sections of sham aorta. In the 7 positive comparisons, the difference in specific binding between DOCA-salt and sham sections ranged from 2.31 to 20.67 gray scale units (gsu) with an average of 9.18 gsu (figure). An increase in specific binding in aorta from DOCA-salt rats suggests the vessels have more EGFR that could facilitate the enhanced contractility to EGF in DOCA-salt aorta.

Grain flow measurements with X-ray techniques

The use of low energy X-rays, up to 30 keV, densitometry is demonstrated for grain flow rate measurements through laboratory experiments. Mass flow rates for corn were related to measured X-ray intensity in gray scale units with a 0.99 correlation coefficient for flow rates ranging from 2 to 6 kg/s. Larger flow rate values can be measured by using higher energy or a higher tube current. Measurements were done in real time at a 30 Hz sampling rate. Flow rate measurements are relatively independent of grain moisture due to a negligible change in the X-ray attenuation coefficients at typical moisture content values from 15 to 25%. Grain flow profile changes did not affect measurement accuracy. X-rays easily capture variations in the corn thickness profile. Due to the low energy of the X-ray photons, biological shielding can be accomplished with 2-mm-thick lead foil or 5 mm of steel.

Measurement of the Time‐Dependent Appearance of Discolored Spots in Alkaline Noodles by Image Analysis

ABSTRACTFresh alkaline noodles prepared from patent flours of the Canadian wheat class Canadian Prairie Spring White (CPSW) AC Karma and AC Vista were characterized by image analysis to numerically evaluate the time‐dependent formation of dark areas (spots) on the noodle surface. The system was able to rapidly detect, measure, and characterize such undesirable discolorations, which commonly form on the surface of raw noodles with time. Variations in minimum spot detection size (0.050–0.250 mm2), in combination with a darkness threshold setting (Δ grey scale units of 2, 5, and 10) were investigated. A linear increase in the number of spots was observed over time for both cultivars with nine combinations of size and darkness. The total number of discolored spots measured was dependent on both detection size and sensitivity (threshold setting). Significant differences (P &lt; 0.05) in the number of darkened spots were detected between the two cultivars only after 24 hr. Similarly, significant differences (P &lt; 0.05) in size of the spots between the two cultivars was observed at 24 hr. Darkening was most rapid within the first hour for both cultivars, followed by a period of stability before a significant (P &lt; 0.05) further increase by 24 hr. Characterization of the darkness distribution indicated significantly different distribution profiles for the two cultivars examined, which was consistent with their noodle brightness (L*) values.

Perinatal Brain Iron Deficiency Predisposes the Rat Hippocampus to Long-term Damage following Hypoxic-ischemic Insult • 1566

The offspring of pregnancies complicated by diabetes mellitus or intrauterine growth retardation are at increased risk for perinatal asphyxia and for long-term neurocognitive sequelae. Both gestational conditions are characterized by an increased prevalence of brain iron deficiency. The hippocampus is important for a variety of cognitive functions (e.g., recognition memory) and is susceptible to hypoxicischemic (HI) injury. To evaluate the hypothesis that brain iron deficiency increases the vulnerability of the hippocampus to HI injury and to assess whether iron induced reperfusion injury has any role in such injuries, we ligated the right common carotid artery in 15 perinatally iron-deficient and 15 iron-sufficient 7-day-old rat pups,and exposed them to 2.5 hours of 8% FIO2(Levine model). The non-ligated left side served as the undamaged internal control. On day 14, neuronal injury was quantified histochemically by assessing intensity of staining for Nissl substance in 4 hippocampal subareas in both hemispheres using optical densitometry in gray scale units (range: 1/white-254/black). To assess iron induced reperfusion injury, sections were stained for iron by modified Perl's reaction. The brain iron concentration of the iron-deficient group was 55% of control (p<0.001). In the iron-deficient group,there was significant loss of Nissl substance on the ligated right side in subareas CA1 (124 ± 14 v. 112 ± 15, p=0.002), CA3ab (144 ± 10 v. 129 ± 15, p=0.001) and the dentate gyrus (136 ± 14 v. 128 ± 13, p=0.012), when compared with the unligated left side.The iron-sufficient group had significant right sided Nissl loss only in CA1 (111 ± 14 v. 106± 15, p = 0.05). The mean number of subareas with detectable right sided Nissl loss per animal was greater in the iron-deficient group than the iron-sufficient group (2.9 ± 1.0 v. 2.0 ± 1.2, p<0.05). The degree of right-sided Nissl substance loss per animal in the iron-deficient group was also greater in CA1(p=0.042), CA3ab(p=0.003) and the dentate gyrus(p=0.037)when compared with the iron-sufficient group. There were no side-to-side differences in the number of iron stained cells in either group. Perinatal iron deficiency increases the vulnerability of hippocampal subareas of CA1, CA3ab and dentate to HI injury. Iron deposition is not involved in the pathophysiology of this injury. These findings may explain the increased risk of perinatal asphyxia and its neurocognitive sequelae in infants born of pregnancies complicated by perinatal iron deficiency.

937-4 Combined Use of Dobutamine Stress Echocardiography and Myocardial Contrast Echocardiography

Combined use of Dobutamine stress Echocardiography (DSE) and Myocardial contrast echocardiography (MCE) offers the unique possibility to study myocardial function and perfusion. To define the characteristics of collateralized myocardium (CM) in comparison to normally perfused myocardium (NM) using DSE and MCE. In 14 patients (pts) (10 males, 4 females) with single vessel total occlusion of one major epicardial coronary artery and intercoronary collaterals (Rentrop3) DSE was performed together with MCE. Wall motion score index (WMSI) was calculated. Sonicated iopamidol was injected into the right and left coronary artery with simultaneous twodimensional Echo imaging of all standard apical views in every patient. Videodensitornetry of contrast enhanced (C) images was used to calculate Intensity (I) increase in gray scale units (U), The same myocardial segments were analyzed to define WMS and U for CM and NM for the presence (+) or absence (-) of wall motion abnormalities. CM NM + - WMSI rest 2.1 ± 0.39 1 ± 0.1 * 1.10 ± 0.09 * stress 2.5 ± 0.61 1.42 ± 0.75 ** 1.19±0.48 MCE (1) 21.5 ± 9.4 40.9 ± 17.6 * 48.0 ± 17.6 * * p &lt; 0.05 + vs -, ** p &lt; 0.05 CM vs NM Despite the presence of large intercoronary collaterals CM has decreased myocardial perfusion which becomes worse if wall motion abnormalities are present Combined use of DSE and MCE provides a unique method to define the characteristics of the myocardium by its contractile function and perfusion.