High Mapping Research Articles

Comparison of Intraocular Pressure, Blood Pressure, Ocular Perfusion Pressure and Blood Flow Fluctuations During Dorzolamide Versus Timolol Add-On Therapy in Prostaglandin Analogue Treated Glaucoma Subjects

Objective: To compare the effects of dorzolamide and timolol add-on therapy in open-angle glaucoma (OAG) patients previously treated with prostaglandin analogue (Pg), by evaluating fluctuations in the intraocular (IOP), blood (BP), ocular perfusion pressures (OPP) and retrobulbar blood flow (RBF) parameters. Methods: 35 OAG patients (35 eyes), 31 women (88.6%) age 63.3 (8.9) years were evaluated in a 3 month randomized, cross-over, single-masked study. During the experiments BP, heart rate, IOP and OPP were assessed 4 times per day (8–12–16–20 h). RBF was measured twice per day (8–20 h) using Color Doppler imaging in the ophthalmic (OA), central retinal (CRA), nasal (nSPCA) and temporal (tSPCA) posterior ciliary arteries. In each vessel, peak systolic velocity (PSV) and end-diastolic velocity (EDV) were assessed and vascular resistance (RI) calculated. Results: Both add-on therapies lowered IOP in a statistically significant manner from 15.7 ± 2.4 mmHg at latanoprost baseline to 14.9 ± 2.2 mmHg using dorzolamide (p < 0.001) and 14.2 ± 1.9 mmHg using timolol (p < 0.001). The IOP lowering effect was statistically significant at 20 h, favoring timolol as compared to dorzolamide (1.4 ± 2.4 vs. 0.2 ± 2.1 mmHg), (p < 0.05). Dorzolamide add-on therapy showed smaller IOP (2.0 ± 1.4), SPP (13.3 ± 7.9), systolic BP (13.5 ± 8.7) and diastolic BP (8.4 ± 5.4) fluctuations as compared to both latanoprost baseline or timolol add-on therapies. Higher difference between morning and evening BP was correlated to decreased evening CRA EDV in the timolol group (c = −0.41; p = 0.01). With increased MAP in the morning or evening hours, we found increased evening OA RI in timolol add-on group (c = 0.400, p = 0.02; c = 0.513, p = 0.002 accordingly). Higher MAP fluctuations were related to impaired RBF parameters during evening hours-decreased CRA EDV (c = −0.408; p = 0.01), increased CRA RI (c = 0.576; p < 0.001) and tSPCA RI (c = 0.356; p = 0.04) in the dorzolamide group and increased nSPCA RI (c = 0.351; p = 0.04) in the timolol add-on group. OPP fluctuations correlated with increased nSPCA RI (c = 0.453; p = 0.006) in the timolol group. OPP fluctuations were not related to IOP fluctuations in both add-on therapies (p < 0.05). Conclusions: Both dorzolamide and timolol add-on therapies lowered IOP in a statistically significant fashion dorzolamide add-on therapy showed lower fluctuations in IOP, SPP and BP. Higher variability of daytime OPP led to impaired RBF parameters in the evening.

In a Porcine Model of Mixed Acidemia HES 130/0.4 May Support More Stable Hemodynamics during CVVH when Compared to Gelatine

Continuous veno-venous hemofiltration (CVVH) and mixed acidemia often occur simultaneously in critically ill patients. In a previous study in non-acidemic pigs we found that colloids and CVVH interact specifically with respect to hemodynamic stability, with favorable effects for 6% HES 130/0.4 versus 4% gelatine (GEL) infusion. In a porcine model, we investigated whether these colloid-type associated differences are still dominant under acidemic conditions. We utilized 5 groups, a non-acidemic reference group receiving HES130 and CVVH; two acidemic groups receiving HES130 infusion (one with and one without CVVH); and two acidemic groups receiving GEL infusion (one with and one without CVVH). Mixed acidemia (pH ~7.20) was established by low tidal volume ventilation and acid infusion. Stable acidemia/CVVH application was maintained for 3 hours. Hemodynamics and blood gases were recorded. Mixed acidemia led to a significant decrease in MAP and increase in MPAP in all groups. CVVH led to a further decrease in MAP but improved MPAP. During CVVH, HES130 ensured significantly higher MAP, Hb, and DO2 values than GEL infusion. In the groups without CVVH these differences between HES 130/0.4 and GEL were not observed. As in a previous study in non-acidemic pigs, we found a colloid-specific influence of HES130 versus GEL on hemodynamics during CVVH under acidemia. Again, HES130 infusion may lead to favorable effects. In contrast, acidemia without CVVH application was dominant over the impact of a respective colloid. The application of a CVVH seems to be an important trigger for the overall circulatory response to a particular colloid.

Blood Pressure Modifies Retinal Susceptibility to Intraocular Pressure Elevation

Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP) is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP). An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine) Long-Evan rats with low (∼60 mmHg, sodium nitroprusside infusion), moderate (∼100 mmHg, saline), or high levels (∼160 mmHg, angiotensin II) of mean arterial pressure (MAP, n = 5–10 per group) were subjected to IOP challenge (10–120 mmHg, 5 mmHg steps every 3 minutes). Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave) and inner retinal function (scotopic threshold response or STR). Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow.

Abstract 3051: Blood Pressure Thresholds to Predict the Cause of Intracerebral Hemorrhage

Introduction: Chronic hypertension is a common cause of spontaneous intracerebral hemorrhage (ICH), but not all patients who are hypertensive on hospital presentation have an ICH caused by hypertension (htnICH). We sought to determine blood pressure (BP) thresholds that correlated with a presumed htnICH in a prospective cohort. Methods: The NIH-funded Diagnostic Utility of MRI in Spontaneous Intracerebral Hemorrhage (DASH) study prospectively enrolled consecutive ICH patients to determine the utility of routine MRI in the diagnosis and management of these patients. Contrast angiography was pursued in a predefined patient subset. At 3 months, ICH cause was determined by the treating stroke physician after review of all clinical information, including MRI in the acute and chronic phase, pathology, and clinic follow-up, as available. Statistical analyses were done using SPSS: χ2; 2 tailed t-tests; and Mann-Whitney U tests were used as appropriate. Receiver operator characteristic (ROC) curves were created and results expressed as area under curve (AUC). Results: We included 136 patients in this report (age: 63±17yrs; ICH volume: 22±27cc; NIHSS: 9±8; GCS: 13±3). Of these, 70% had a history of hypertension, 40% had an admission SBP&gt; 180mmHg, and 22% an admission SBP &gt;200mmHg. Sixty patients (44%) had htnICH as their final diagnosis. A history of hypertension was associated with htnICH (χ2=11.8, p&lt;0.001), but 48% (46/95) of patients with a history of hypertension did not have a htnICH. Patients with a htnICH had: higher SBP (189 vs 157mmHg, p&lt;0.0001); higher MAP (131 vs 110mmHg, p&lt;0.0001), higher NIHSS (12 vs 6.5, p&lt;0.0001); smaller ICH volumes (16.6 vs 26.0cc, p=0.03); and non-lobar hematomas (χ2=62.3, p180mmHg was 74% specific and 58% sensitive for a subsequent diagnosis of htnICH, a SBP&gt; 200mmHg was 90% specific and 37% sensitive, and a MAP &gt;132mmHg was 90% specific and 45% sensitive. Using ROC analysis, MAP predicted hypertensive etiology with an AUC of 0.75 (p&lt;0.0001, 95% CI: 0.67-0.83). Patients with htnICH and MAP 132mmHg based on age, NIHSS, gender, ICH volume, or ICH location (lobar vs non-lobar). Conversely, patients with non-htnICH and MAP &gt;132mmHg on admission tended to have larger ICH volumes (44 vs 24cc, p=0.07) and higher NIHSS (10 vs 6, p=0.21), but did not differ by location from those with a MAP&lt;132mmHg. Non-lobar location alone was 74% specific and 93% sensitive for htnICH, and a non-lobar ICH or a MAP&gt;132mmHg was 64% specific and 95% sensitive for htnICH. Conclusions: In our cohort, a history of hypertension predicted htnICH no better than chance. An admission SBP &gt;200mmHg or a MAP &gt;132mmHg predicted htnICH in 90% of these patients, but missed two-thirds of cases. ICH location alone was a sensitive predictor of htnICH, but blood pressure thresholds were more specific.

Association of Cardiac Baroreflex Sensitivity with Blood Pressure Transients: Influence of Sex and Menopausal Status

The magnitude of decrease in blood pressure (BP) during a vasoactive drug bolus may be associated with the calculated baroreflex sensitivity (BRS). The purpose of the present study was to evaluate whether sympathetic and/or cardiac BRS relates to the extent of change in BP and whether this was altered by sex hormones. Fifty-one young women (27 ± 1 years), 14 older women (58 ± 1 years), and 36 young men (27 ± 1 years) were studied. Heart rate, BP, and muscle sympathetic nerve activity (MSNA) were monitored. Sympathetic BRS was analyzed using the slope of the MSNA-diastolic blood pressure (DBP) relationship and cardiac BRS was analyzed using the R–R interval-systolic blood pressure (SBP) relationship. Young women and men had similar mean arterial pressures (MAP, 91 ± 1 vs. 90 ± 1 mmHg), cardiac BRS (19 ± 1 vs. 21 ± 2 ms/mmHg), and sympathetic BRS (−6 ± 1 vs. −7 ± 1 AU/beat/mmHg), respectively. Older women had higher MAP (104 ± 4 mmHg, p < 0.05) and lower cardiac BRS (7 ± 1 ms/mmHg, p < 0.05), but similar sympathetic BRS (−8 ± 1 AU/beat/mmHg). There was no association between BP transients with either cardiac or sympathetic BRS in young women. In the older women, the drop in SBP, DBP, and MAP were associated with cardiac BRS (r = 0.60, r = 0.59, and r = 0.70, respectively; p < 0.05), but not sympathetic BRS. The decrease in SBP was positively related to cardiac BRS in young men (r = 0.41; p < 0.05). However, there was no relationship between the decrease in BP and sympathetic BRS. This indicates that older women and young men with low cardiac BRS have larger transients in BP during nitroprusside. This suggests a more prominent role for cardiac (as opposed to sympathetic) BRS in responding to acute BP changes in young men and older women. The fact that these relationships do not exist in young women suggest that the female sex hormones influence baroreflex responses.

The epistasis between vascular homeostasis genes is apparent in essential hypertension

Objective The epistasis influence of vascular homeostasis genes is vital to multigenetic diseases. This study was designed to perceive the possible role of epistasis in the etiology of essential hypertension. Methods We investigated seven polymorphisms of ACE, CYP11B2 and NOS3 epistatically, and SBP, DBP, MAP, ACE activity, plasma aldosterone concentration (PAC) and NOx level in 860 age- and ethnicity-matched unrelated north-Indian subjects. Results The hypertension risk in individuals with interacted-genotypes (IwIw + IwIc) + (4aa), (IcIc) + (4bb + 4ba) and IcIc + 4aa of the CYP11B2 and NOS3 was significantly higher with odds ratio 5.5 (95% CI = 2.9–10.6, P < 0.0001), 2.4 (95% CI = 1.4–4.1, P < 0.0008) and 7.5 (95% CI = 1.6–34.8, P = 0.010), respectively. The odds ratio for hypertension with interacted-haplotypes (−344T/Ic) + (−922A/−786T/4a/894G) and (−344T/Ic) + (−922G/−786C/4a/894G) of CYP11B2 and NOS3 was 5.3 (95% CI = 2.0–14.2, P = 0.005) and 3.9 (95% CI = 1.4–10.4, P = 0.04), respectively; whereas for the protective interacted-haplotypes (−344T/Iw) + (−922A/−786T/4b/894G), the odds ratio was 0.7 (95% CI = 0.5–0.9, P = 0.03). While the interacted-genotypes, IcIc + 4aa correlated with higher SBP and MAP ( P = 0.006; P = 0.04), the interacted-haplotypes, (−344T/Ic) + (−922A/−786T/4a/894G) and (−344T/Ic) + (−922G/−786C/4a/894G) correlated with higher MAP and lower NOx level ( P = 0.02 and P = 0.03, respectively), and the protective interacted-haplotypes (−344T/Iw) + (−922A/−786T/4b/894G) correlated with lower PAC and MAP ( P = 0.024 and P = 0.018, respectively). Conclusions The epistasis between CYP11B2 and NOS3 and its correlation with varied clinical and biochemical parameters signify its possible contribution in the complex etiology of hypertension.

Association between intraoperative tissue oxygenation, arterial blood pressure and noradrenaline use in urological patients

Background and Goal of Study: Inadequate tissue oxygenation should be prevented during surgery as it might cause postoperative morbidity. In this observational study we looked at factors that might influence tissue oxygenation (StO2) such as blood pressure and use of vasoactive drugs. Materials and Methods: In 159 urological patients receiving balanced anaesthesia and mechanical ventilation, we measured StO2 intraoperatively on the thenar eminescence (InSpectra, Hutchinson Tech., USA) along with (non)invasive blood pressure and recorded the use of noradrenaline. We correlated StO2 and MAP as recorded at defined moments during surgery. In addition, we looked at the effects of low blood pressure (as defined by the areas under the curve (AUC) while MAP was < 65 mmHg) on StO2. Furthermore, we related StO2 to different noradrenaline (NA) dosages: none, low (<0.03 mg/kg/min) and high dose (≥0.03 mg/kg/min). Results and Discussion: At the start and end of surgery, there was no correlation between StO2 and MAP. However, the lowest recorded MAP per patient did correlate with the corresponding StO2 (R=0.206, R2=0.043, p< 0.01; Pearson‘s correlation, 2-tailed). Similarly, a higher MAP AUC < 65 mmHg was associated with a lower average StO2 (R=-0.189, R2=0.036, p< 0.05; Spearman‘s correlation, 2-tailed). These results support the hypothesis of intact autoregulation of tissue blood flow to preserve StO2 in the normal range of blood pressure, whereas this autoregulation fails during lowest pressures. Furthermore, StO2 was higher without noradrenaline (no NA)(88.4%) than during high dose noradrenaline (85.2%) (p< 0.001; ANOVA, Bonferroni post hoc analysis). Possibly, the vasoconstrictive effect of noradrenaline decreases blood flow through the observed tissue (peripheral muscle). Conclusions: Tissue oxygenation is not influenced by blood pressure in the normal blood pressure range during anaesthesia, whereas it becomes dependent when MAP drops below the clinically relevant threshold of 65 mmHg. Noradrenaline use is associated with a decreased tissue oxygenation in the thenar eminescence. Further studies should identify other factors that may influence tissue oxygenation and assess the impact of tissue hypoxia on postoperative patients‘ outcome.

Assessing the prospects of genome-wide association studies performed in inbred mice

The remarkable success in mapping genes linked to a number of disease traits using genome-wide association studies (GWAS) in human cohorts has renewed interest in applying this same technique in model organisms such as inbred laboratory mice. Unlike humans, however, the limited genetic diversity in the ancestry of laboratory mice combined with selection pressure over the past decades have yielded an intricate population genetic structure that can complicate the results obtained from association studies. This problem is further exacerbated by the small number of strains typically used in such studies where multiple spurious associations arise as a result of random chance. We sought to empirically assess the viability of GWAS in inbred mice using hundreds of expression traits for which the true location of the expression quantitative trait locus was known a priori. We then measured transcript abundance levels for these expression traits in 16 classical and 3 wild-derived inbred strains and carried out a genome-wide association scan, demonstrating the low statistical power of such studies and empirically estimating the large extent to which allelic association of transcripts gives rise to spurious associations. We provide evidence illustrating that in a large fraction of cases, the marker with the most significant p values fails to map to the location of the true eQTL. Finally, we provide experimental support for hundreds of traits, and that combining linkage analysis with association mapping provides significant increases in statistical power over a stand-alone GWAS as well as significantly higher mapping resolution than either study alone.

Mapping of aggregated floodplain plant communities using image fusion of CASI and LiDAR data

Combined optical and laser altimeter data offer the potential to map and monitor plant communities based on their spectral and structural characteristics. A problem unresolved is, however, that narrowly defined plant communities, i.e. plant communities at a low hierarchical level of classification in the Braun-Blanquet system, often cannot be linked directly to remote sensing data for vegetation mapping. We studied whether and how a floristic dataset can be aggregated into a few major discrete, mappable classes without substantial loss of ecological meaning. Multi-source airborne data (CASI and LiDAR) and floristic field data were collected for a floodplain along the river Waal in the Netherlands. Mapping results based on floristic similarity alone did not achieve highest levels of accuracy. Ordination of floristic data showed that terrain elevation and soil moisture were the main underlying environmental drivers shaping the floodplain vegetation, but grouping of plant communities based on their position in the ordination space is not always obvious. Combined ordination-based grouping with floristic similarity clustering led to syntaxonomically relevant aggregated plant assemblages and yielded highest mapping accuracies.

82: Continuous Hematocrit (HCT) During Dialysis. Relationship of Max HCT (MH)To Final HCT (FH)

CONTINUOUS HEMATOCRIT (HCT) DURING DIALYSIS. RELATIONSHIP OF MAX HCT (MH)TO FINAL HCT (FH) Michael Germain∗ Brian H Nathanson# Susan Pickard∗Baystate Medical Center Springfield Ma USA #Optistatim LLC Longmeadow Ma USA As part of an ongoing study of 3 X week hct measurements to evaluate hct variability, we evaluated the relationship of MH to FH. The critline device, which measures continuous hct during dialysis, was used in all 49 patients in a dialysis unit. All treatments for the 1 3 months of the study were analyzed. Two distinct patterns were seen. 10/49 patients had large differences (LD) in the MH vs FH and 39 patients had small differences (SD) (0.46(.62) vs. 0.21(.44) p < 0.001). The SD group had 691/1274 observations with the MH identical to the FH. The LD group had significantly higher dry wts, smaller wt gains, higher MAP, higher hgb, lower EPO dose, less hgb variability (more time that hgb is in target range) than the SD group. The 2 graphs show representative pts. A LD in max hct vs final hct may identify a “healthier” cohort. These patients can “refill” their intravascular volume at the end of dialysis after fluid removal to dry wt. These patient also appear to have more stable hgbs in the target range with lower EPO doses.

Deleterious Cardiovascular Effects of Antenatal Betamethasone Exposure in Young and Adult Sheep

Betamethasone (Beta) administration prior to premature delivery in early third trimester is employed to accelerate lung development and improve survival. Male adult sheep (1.8 years) exposed at 80th day of gestation to Beta (Ad‐Beta) had elevated arterial pressure (MAP), increased left ventricle to body weight ratio (LV/BW), and attenuated baroreflex sensitivity for control of heart rate (BRS) compared to age‐matched controls (Ad‐Veh). We have now determined that young sheep (0.5 years) exposed antenatally to Beta (Y‐Beta) had higher MAP (95 ± 2 vs 77 ± 2 mm Hg; p &lt; 0.05) and lower BRS (3.9 ± 1.2 vs 10.4 ± 1.8 ms/mm Hg; p &lt; 0.05) compared with Y‐Veh. However, at this age there was no difference in LV/BW between Y‐Beta and Y‐Veh groups. The AT1 angiotensin antagonist candesartan (0.3 mg/kg, iv) normalized MAP and improved BRS in Y‐Beta sheep. Heart rate variability (HRV) and blood pressure variability (BPV), measured by time and frequency domain analysis, revealed that Y‐Beta sheep had significantly lower HRV (SDRR, rMSSD, LFRRI, and HFRRI) compared with Y‐Veh and higher BPV (SDMAP, LFSAP). Candesartan partially restored HRV in Y‐Beta sheep and fully corrected BPV. Thus, in utero exposure to Beta increases MAP and impairs baroreflex control of heart rate in young sheep. The deleterious actions of antenatal steroids persisted into adulthood, likely contributing to LV hypertrophy in adult sheep. HD047584

Oxidative stress does not mediate hypertension and renal injury in ovariectomized DS rats

Blood pressure (BP) increases in postmenopausal women. BP is higher in ovariectomized (OVX) Dahl salt sensitive rats (DS) compared to intact females (INT). Estrogen is an antioxidant. We hypothesized that OVX leads to increased oxidative stress (ROS), increased BP and renal injury. INT and OVX, 13 weeks of age (n=4–6/grp), were given low salt (LS) diet 0.3%, and supplemented with either tempol (T) (1mmol/L, p.o.) or water for 2 weeks. BP was measured via femoral catheter. ROS was measured by lucigenin in kidney. Urinary albumin (UAlb) and nitrate/nitrite excretion (UNOx) were measured at the end. OVX on LS had higher MAP than INT, and T had no effect in either group. ROS was higher in OVX than INT, and was reduced with T in OVX. UAlb was higher in OVX, and was not affected by T in either group. UNOx was higher in INT than OVX, and was increased with T only in OVX. Despite the fact that ROS are higher and UNOx increases with T in OVX, ROS play no role in mediating HT or renal injury in OVX DS rats on LS. These data suggest that antioxidants may not reduce BP or renal injury in postmenopausal women. (Supported by NIH HL66072)

Visual interpretation of ASTER satellite data, Part II: Land use mapping in Mpumalanga,South Africa

Since the initiation in 1960 of the era of satellite remote sensing to detect the different characteristics of the earth, a powerful tool was created to aid researchers. Many land-use studies were undertaken using Landsat MSS, Landsat TM and ETM, as well as SPOT satellite data. The application of these data to the mapping of land use and land cover at smaller scales was constrained by the limited spectral and/or spatial resolution of the data provided by these satellite sensors. In view of the relatively high cost of SPOT data, and uncertainty regarding the future continuation of the Landsat series, alternative data sources need to be investigated. In the absence of published previous research on this issue in South Africa, the purpose of this article is to investigate the value of visual interpretation of ASTER satellite images for the identification and mapping of land-use in an area in South Africa. The study area is situated in Mpumalanga, in the area of Witbank, around the Witbank and Doorndraai dams. This area is characterised by a variety of urban, rural and industrial land uses. Digital image processing of one Landsat 5 TM, one Landsat 7 ETM and one ASTER satellite image was undertaken, including atmospheric correction and georeferencing, natural colour composites, photo infrared colour composites (or false colour satellite images), band ratios, Normalised Difference Indices, as well as the Brightness, Greenness and Wetness Indices. The efficacy with which land use could be identified through the visual interpretation of the processed Landsat 5 TM, Landsat 7 TM and ASTER satellite images was compared. The published 1:50 000 topographical maps of the area were used for the purpose of initial verification. Findings of the visual interpretation process were verified by field visits to the study area. The study found that the ASTER satellite data produced clearer results and therefore have a higher mapping ability and capacity than the Landsat satellite data. Hence, it is anticipated that the use of the full range of the spectral resolution of the ASTER satellite data – which were not available for this study – in statistical pattern recognition and classification methods will enhance the value of the process. Statistical methods are often used to produce visual information which could be applied to prepare land-use change inventories. This should be addressed in future research projects. Should the Landsat programme be terminated, ASTER satellite data might provide the best alternative for a variety of research projects, but if the Landsat project is continued, the ASTER satellite data could be used very effectively in conjunction with the Landsat satellite data. Since it is foreseen that the ASTER satellite data will be available for at least the next 12 to 15 years, it will continue to provide exciting possibilities for the development of programmes to monitor land-use and land-use change. This could then be used by all three levels of government to reach their goals in terms of agricultural planning, town and regional planning and environmental management. These requirements are described in the Integrated Development Programmes (IDP) of the different local governments.

The influence of travel experiences and exposure to cartographic media on the ability of ten‐year‐old children to draw cognitive maps of the world

It is assumed that foreign holidays and previous exposure to cartographic media play a role in the development of children's spatial cognition and map‐drawing ability. Few empirical studies to date have focused on the development of these spatial cognitive representations. This study examined the map‐drawing abilities of an international sample of 432 ten‐year‐old children. It examined the nature of the world maps they drew. It explored the extent to which more travel experiences and greater previous exposure to cartographic media were correlated to enhanced ability of children to represent their spatial cognitive structure of the world as a drawn map. Results indicated that both travel experiences (in male students) and exposure to cartographic media (in both female and male students) were positively correlated with effective map drawing. Male children had more previous exposure to cartographic media than female children. This exposure was 60% more correlated to higher map drawing ability for male, than for female students. The paper discusses the implications of findings for the creation of learning environments which support the development of map‐drawing.

Vasoactivity of Bovine Polymerized Hemoglobin (HBOC-201) in Swine With Traumatic Hemorrhagic Shock With and Without Brain Injury

We previously reported that bovine polymerized hemoglobin (HBOC- 201) improved outcome in swine with hemorrhagic shock (HS) with and without traumatic brain injury (TBI). Herein, we add analyses of blood pressure (BP) responses, associated physiologic data, and HS fluid infusion guidelines. HBOC-201 versus standard fluid resuscitation was compared in four anesthetized invasively monitored swine models: moderate controlled HS, severe controlled HS, severe uncontrolled HS (liver injury), and severe uncontrolled HS/TBI (liver/parietal brain injuries). Pigs received fluid for hypotension and tachycardia, and were followed up to 6 (HS alone) or 72 hours (HS/TBI). The change in mean arterial pressure (DeltaMAP) response severity was stratified and analyzed based on infusion number and HS severity, using Student's t and Fisher's exact tests. HBOC-201 vasoactivity resulted in higher MAP in all studies. Among HBOC-201 pigs, DeltaMAP responses were significant for the first two infusions and inversely related to HS severity. Among controls, DeltaMAP responses remained significant through the fourth infusion in controlled HS models, and through the first in severe uncontrolled HS/TBI; none were significant in severe uncontrolled HS. DeltaMAP was higher with HBOC-201 through the first infusion in moderate controlled HS, the fifth in severe uncontrolled HS, and the second in severe uncontrolled HS/TBI; there were no group differences in severe controlled HS. No severe MAP responses occurred. Higher DeltaMAP severity did not impact outcome. Hypotension satisfied fluid reinfusion criteria less consistently than tachycardia. Overall, HBOC-201 improved physiologic parameters and survival without causing hypoperfusion; in severe HS, perfusion improved. In swine with HS +/- TBI, HBOC-201 had mild to moderate vasoactivity, resulting in significant DeltaMAP responses mainly after initial infusions, no severe/adverse responses, and improved outcome. Our data suggest that use of physiologic parameters (e.g., tachycardia), in addition to hypotension to guide fluid reinfusion during HS resuscitation with HBOC-201, will minimize hypoperfusion risk and maximize potential benefit.

Role of Extracellular Superoxide Dismutase in the Mouse Angiotensin Slow Pressor Response

Low rates of angiotensin II (Ang II) infusion raise blood pressure, renal vascular resistance (RVR), NADPH oxidase activity, and superoxide. We tested the hypothesis that these effects are ameliorated by extracellular superoxide dismutase (EC-SOD). EC-SOD knockout (-/-) and wild type (+/+) mice were equipped with blood pressure telemeters and infused subcutaneously with Ang II (400 ng/kg per minute) or vehicle for 2 weeks. During vehicle infusion, EC-SOD -/- mice had significantly (P<0.05) higher MAP (+/+: 107+/-3 mm Hg versus -/-: 114+/-2 mm Hg; n=11 to 14), RVR, lipid peroxidation, renal cortical p22(phox) expression, and NADPH oxidase activity. Ang II infusion in EC-SOD +/+ mice significantly (P<0.05) increased MAP, RVR, p22(phox), NADPH oxidase activity, and lipid peroxidation. Ang II reduced SOD activity in plasma, aorta, and kidney accompanied by reduced renal EC-SOD expression. During Ang II infusion, both groups had similar values for MAP (+/+ Ang II: 125+/-3 versus -/- Ang II: 124+/-3 mmHg; P value not significant), RVR, NADPH oxidase activity, and lipid peroxidation. SOD activity in the kidneys of Ang II-infused mice was paradoxically higher in EC-SOD -/- mice (+/+: 8.8+/-1.2 U/mg protein(-1) versus -/-: 13.7+/-1.6 U/mg protein(-1); P<0.05) accompanied by a significant upregulation of mRNA and protein for Cu/Zn-SOD. In conclusion, EC-SOD protects normal mice against oxidative stress by attenuating renal p22(phox) expression, NADPH oxidase activation, and the accompanying renal vasoconstriction and hypertension. However, during an Ang II slow pressor response, renal EC-SOD expression is reduced and, in its absence, renal Cu/Zn-SOD is upregulated and may prevent excessive Ang II-induced renal oxidative stress, renal vasoconstriction, and hypertension.

WISE‐2005: Adrenergic responses to 60 days of 6o head‐down bed‐rest (BR) in women with exercise counter‐measures

Women are especially susceptible to orthostatic intolerance on return from space or after BR. Before and after 2 doses of isoproterenol (ISO) or norepinephrine (NOR) MAP, HR, cardiac output (Q), stroke volume (SV), and total peripheral resistance (TPR) were measured in 8 controls and 8 women with flywheel and lower body negative pressure treadmill exercise (EX). Pre-BR, ISO2 caused: higher HR, higher SV, higher Q, and lower TPR. NOR2 caused: lower SV, lower Q, higher TPR and higher MAP. Post-BR controls show higher baseline HR (64.9 ± 2.3 to 72.5 ± 4.8 bpm) and no increase in MAP due to NOR1. Post-BR EX show no increase of baseline HR, higher baseline TPR (18.0 ± 2.1 to 20.2 ± 2.8 mmHg/mL/min), reduced baseline Q (5.5 ± 0.5 mL/min to 4.5 ± 0.5 mL/min), reduced Q with ISO2 (Pre: 8.6 ± 0.9 mL/min; Post: 7.5 ± 0.8 mL/min), augmented TPR with NOR1 (Pre: 19.4 ± 2.2 mmHg; Post: 23.7 ± 3.3 mmHg). Controls show decreased peripheral and increased cardiac sensitivity of adrenergic receptors. EX show increased peripheral sensitivity without cardiac augmentation. We conclude that exercise is cardioprotective after exposure to 60-day BR (CSA, NASA, ESA & CNES).

AT1, AT2 and mas Receptor Expression in the Uteroplacental Unit of Normotensive and Hypertensive Rats

Late pregnancy is associated with enhanced uterine and placental levels of angiotensin peptides but a marked decrease in Ang-(1–7) occurs during hypertensive pregnancy. We investigated AT1, AT2 and mas/AT1-7 receptors in the uteroplacental unit of normal (NP) and reduced uterine perfusion pressure (RUPP) pregnant rats at late gestation by receptor autoradiography using 125I-Sar1-Thr8-Ang II and reverse transcriptase real time PCR. RUPP rats had higher MAP (109±1 vs 121±1 mmHg, p<0.05). In myo- and endometrium of virgin uterus there was 80-90% competition with the AT1 receptor antagonist losartan and ~10–20% competition with AT2/mas receptor antagonists (PD123319 and D-Ala). AT1 binding density was higher in myo- vs. endometrium (142 ± 68 vs 50 ± 34, p<0.01). In NP and RUPP, AT1 binding predominates in the mesometrial triangle with little to no competition with PD or D-Ala. The AT1 density was 1.6 fold greater in RUPP vs. NP (p<0.05). AT1, AT2 and mas receptor mRNA was lower in uterus of NP (58%, 98% and 76%, p<0.05) and RUPP (55%, 97% and 81%) vs virgin. AT1 receptor binding and mRNA in fetal and fetal/maternal placenta respectively were similar between RUPP and NP. In the fetal placenta of NP, 23% competition occurred with PD (p=.0505) and in RUPP there was 17% competition with D-Ala. AT1 receptor accounts for the majority of binding in the uteroplacental unit of both NP and RUPP. During normal and hypertensive pregnancy expression of all receptors are reduced in the uteroplacental unit; however in the fetal placenta there is a shift from AT2 to mas/AT1-7 receptors in hypertensive pregnancy. Supported by NHLBI51952 and AHA 0565390U

Estimating and accommodating uncertainty through the soft classification of remote sensing data

Land cover mapping is perhaps the most important application of remote sensing data. The abundance of mixed pixels (representing uncertainties in class allocation), particularly in coarse spatial resolution images, has always been known to lead to difficulties in producing accurate land cover classifications. Soft classification methods may help in quantifying uncertainties in areas of transition between various types of land cover. This study aims to estimate and accommodate uncertainties in all stages of a supervised classification process (i.e. training, allocation and testing) so as to produce accurate and meaningful land cover classifications. Three soft classification methods have been used—a probabilistic maximum likelihood classifier and the two classifiers based on fuzzy set theory (fuzzy c‐means and possibilistic c‐means). Uncertainty and accuracy measures based on a fuzzy error matrix have been adopted to evaluate each classifier. All of the classifiers show an increase in classification accuracy when uncertainty is appropriately accounted for in all stages of the supervised classification. In particular, the possibilistic c‐means classifier produced the highest map and individual class accuracy and has been found to be more robust to the existence of uncertainties in the datasets. The approach suggested in this paper can be used to generate accurate land cover maps, even in the presence of uncertainties in the form of mixed pixels in remote sensing images.

Role of nitric oxide in regional blood flow in angiotensin II-induced hypertensive rats.

The present study was designed to evaluate the contribution of nitric oxide (NO) to regional hemodynamics during the early phase of angiotensin II (Ang II)-induced hypertension. The responses of regional blood flow to chronic NO synthase inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME) were assessed using radioactive microspheres in conscious Ang II-infused hypertensive rats. Ang II-infused rats (270 ng/kg/min, subcutaneously for 12 days: n=11) showed higher mean arterial pressure (MAP: 153+/-4 mmHg) and total peripheral resistance (TPR: 1.61+/-0.06 mmHg/min/ml), and lower cardiac output (CO: 102+/-3 ml/min) than vehicle-infused normotensive rats (115+/-2 mmHg, 0.96+/-0.05 mmHg/min/ml and 130+/-7 ml/min, n=11, respectively). The blood flow rates in the brain, spleen, large intestine and skin were significantly reduced in Ang III-infused rats compared with vehicle-infused rats, while those in the lung, heart, liver, kidney, adrenal gland, small intestine, and skeletal muscle were similar. Treating Ang II-infused rats with L-NAME (75 mg/l in drinking water for 10 days, n=11) resulted in higher MAP (166+/-6 mmHg) and TPR (1.89+/-0.18 mmHg/min/ml) and lower CO (87+/-7 m/min) than untreated Ang II-infused rats. L-NAME-treated Ang II-infused rats showed widespread increases in regional vascular resistance and reduced blood flow rates in the kidney (3.81+/-0.27 ml/min/g) and skeletal muscle (0.20+/-0.03 ml/min/g) compared with untreated Ang II-infused rats (6.88+/-0.27 and 0.33+/-0.04 ml/min/g, respectively). However, there were no significant differences in the flow rates of other organs investigated between these animals. An NO donor, (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409: 30 microg/kg/min, i.v.), significantly decreased MAP (110+/-6 mmHg) and TPR (1.23+/-0.18 mmHg/min/ml) without significant changes in CO (89+/-9 ml/min) in L-NAME-treated Ang II-infused rats. Furthermore, FK409 partially reversed blood flow rates in the kidney (4.72+/-0.40 ml/min/g) and skeletal muscle (0.25+/-0.02 ml/min/g)in these animals. These results suggest that NO counteracts, at least in part, the vasoconstrictor effects of elevated Ang II levels in renal and skeletal muscle vascular beds, and is an important modulator in the regulation of blood flow to these organs during the development of Ang II-induced hypertension.