Nature exposure and mental health during the COVID-19 pandemic: A Navigation Guide systematic review with meta-analysis.

Prior reviews have highlighted that nature exposure was a valuable coping strategy enchancing mental health during the COVID-19 pandemic. However, no existing reviews have determined the quality of evidence and risk of bias of the empirical studies supporting this claim. To address this gap, we employed a Navigation Guide systematic review and meta-analysis approach to investigate associations between nature exposure and mental health during the pandemic. Searches in PubMed, Web of Science, Scopus, CINAHL, and PsycInfo retrieved relevant articles published between January 1, 2020, and March 4, 2024. We used the Navigation Guide methodology to assess the risk of bias and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) assessment to evaluate the overall quality of evidence. Our search retrieved 113 studies that met the inclusion criteria and reported diverse types of exposure, including nature availability, nature visit frequency, green space accessibility, and green space type, alongside associations with 12 mental health outcomes. Meta-analyses found access to gardens was associated with lower odds of depression [(Pooled OR=0.71, 95%CI=0.61, 0.82), I2=0%, n=3] and anxiety [(Pooled odds ratio [OR]=0.73, 95%CI=0.63, 0.84), I2=0%, n=3]. Increased time in green spaces were associated with lower level of stress [(Pooled Corr=-0.11, 95%CI=-0.17, -0.05), I2=0%, n=2]. Higher frequency of visits to nature was associated with improved mental well-being [(Pooled standardized beta estimate during COVID-19 period [ES]=0.10, 95%CI=0.07, 0.14), I2=0%, n=2] and general mental health [(Pooled standardized beta estimate [ES]=0.11, 95%CI=0.03-0.38), I2=82%, n=2]. However, the number of pooled studies was small and the overall quality of evidence was "very low" for all outcomes, and high levels of bias were observed (26% of studies had high, 71% probably high). Nonetheless, given the trends in the results, nature-based solutions emphasizing exposure to gardens and green spaces near the home may have promoted psychological resilience during this public health crisis.

Greenness, air pollution, and temperature exposure effects in predicting premature mortality and morbidity: A small-area study using spatial random forest model.

BACKGROUND: Although studies have provided negative impacts of air pollution, heat or cold exposure on mortality and morbidity, and positive effects of increased greenness on reducing them, a few studies have focused on exploring combined and synergetic effects of these exposures in predicting these health outcomes, and most had ignored the spatial autocorrelation in analyzing their health effects. This study aims to investigate the health effects of air pollution, greenness, and temperature exposure on premature mortality and morbidity within a spatial machine-learning modeling framework. METHODS: Years of potential life lost reflecting premature mortality and comparative illness and disability ratio reflecting chronic morbidity from 1673 small areas covering Greater Manchester for the year 2008-2013 obtained. Average annual levels of NO2 concentration, normalized difference vegetation index (NDVI) representing greenness, and annual average air temperature were utilized to assess exposure in each area. These exposures were linked to health outcomes using non-spatial and spatial random forest (RF) models while accounting for spatial autocorrelation. RESULTS: Spatial-RF models provided the best predictive accuracy when accounted for spatial autocorrelation. Among the exposures considered, air pollution emerged as the most influential in predicting mortality and morbidity, followed by NDVI and temperature exposure. Nonlinear exposure-response relations were observed, and interactions between exposures illustrated specific ranges or sweet and sour spots of exposure thresholds where combined effects either exacerbate or moderate health conditions. CONCLUSION: Air pollution exposure had a greater negative impact on health compared to greenness and temperature exposure. Combined exposure effects may indicate the highest influence of premature mortality and morbidity burden.

To use or not to use proprietary street view images in (health and place) research? That is the question.

Computer vision-based analysis of street view imagery has transformative impacts on environmental assessments. Interactive web services, particularly Google Street View, play an ever-important role in making imagery data ubiquitous. Despite the technical ease of harnessing millions of Google Street View images, this article questions the current practices in using this proprietary data source from a European viewpoint. Our concern lies with Google's terms of service, which restrict bulk image downloads and the generation of street view image-based indices. To reconcile the challenge of advancing society through groundbreaking research while maintaining data license agreements and legal integrity, we believe it is crucial to 1) include an author's statement on using proprietary street view data and the directives it entails, 2) negotiate academic-specific license to democratize Google Street View data access, and 3) adhere to open data principles and utilize open image sources for future research.

Measuring the 3-30-300 rule to help cities meet nature access thresholds.

The 3-30-300 rule offers benchmarks for cities to promote equitable nature access. It dictates that individuals should see three trees from their dwelling, have 30 % tree canopy in their neighborhood, and live within 300 m of a high-quality green space. Implementing this demands thorough measurement, monitoring, and evaluation methods, yet little guidance is currently available to pursue these actions. To overcome this gap, we employed an expert-based consensus approach to review the available ways to measure 3-30-300 as well as each measure's strengths and weaknesses. We described seven relevant data and processes: vegetation indices, street level analyses, tree inventories, questionnaires, window view analyses, land cover maps, and green space maps. Based on the reviewed strengths and weaknesses of each measure, we presented a suitability matrix to link recommended measures with each component of the rule. These recommendations included surveys and window-view analyses for the '3 component', high-resolution land cover maps for the '30 component', and green space maps with network analyses for the '300 component'. These methods, responsive to local situations and resources, not only implement the 3-30-300 rule but foster broader dialogue on local desires and requirements. Consequently, these techniques can guide strategic investments in urban greening for health, equity, biodiversity, and climate adaptation.

Environmental correlates of adolescent active travel to school in Asia: An ecological study.

OBJECTIVES: This study aimed to examine the association between country-level environmental correlates and the prevalence of active school travel (AST) in Asia and country-level differences in AST by age and sex. METHODS: This ecological study involved 31 Asian countries. Dependent variables were AST prevalence, AST prevalence difference by age, and by sex. Independent variables were country-level environmental correlates extracted using publicly available datasets, classified into physical and social environments. Association estimates of each dependent variable and each of the independent variables were calculated using univariate linear regression. All variables were standardized to have a mean of 0 and a standard deviation of 1. RESULTS: Results showed that 1 standard deviation (SD) difference in urban population percentage, night-time light, secondary-school enrolment, and prevalence of adult insufficient physical activity were negatively associated with AST prevalence (SD difference: -0.44 (-0.78 to -0.09), -0.40 (-0.76 to -0.04), -0.39 (-0.74 to -0.04), and -0.40 (-0.76 to -0.03), respectively). A 1 SD difference in car per people was associated with a -0.46 (-0.84 to -0.09) difference of AST prevalence by age. A 1 SD difference in PM2.5 concentration and of prevalence of adult insufficient physical activity were associated with a difference of 0.38 (0.01-0.74) and 0.42 (0.03-0.80) difference of AST prevalence by sex. CONCLUSIONS: This study shows that Asian countries with a greater number of people living in urban areas, lower levels of overall adult physical activity and higher levels of night-time light have a lower prevalence of adolescent AST. Country-level physical and social environmental correlates explained some of the regional variance in AST. Future policy actions and interventions for the region need to be contextually sensitive to the environmental correlates that vary between countries.

Demystifying normalized difference vegetation index (NDVI) for greenness exposure assessments and policy interventions in urban greening.

Most nature and health research use the normalized difference vegetation index (NDVI) for measuring greenness exposure. However, little is known about what NDVI measures in terms of vegetation types (e.g., canopy, grass coverage) within certain analysis zones (e.g., 500 m buffer). Additionally, exploration is needed to understand how to interpret changes in average NDVI (e.g., per 0.1 increments) exposure in relation to changes in vegetation amount and types. In this study, we aimed to explore what vegetation types and amounts best explain the average NDVI and how changes in average NDVI values indicate changes in different vegetation coverages. We used spatial modeling to sample mean NDVI and percentages of vegetation for sample locations within the Greater Manchester case study area. We fitted linear, nonlinear, and mixed multivariate and univariate generalized additive models (GAMs) for multiple spatial scales to identify the relationships between NDVI and vegetation amount and types. Our results showed that the relationships between NDVI and individual vegetation types mostly follow nonlinear trends. We found that canopy and shrubs coverage exhibited a greater influence on mean NDVI exposure values than grass coverage at 300 and 500 m indicating that NDVI values are sensitive to certain types and amounts of vegetation within various buffer zones. We also identified increment in mean NDVI exposure values at lower, mid, and high ranges might be associated with varying changes in total greenspace percentage and individual vegetation types. For instance, at 300 m buffer, an increment of mean NDVI in the lower range (e.g., from 0.2 to 0.3) is associated with an about 17% increase in greenspace percentage. Overall, interpreting changes in NDVI values for urban greening interventions would require careful evaluation of the relative changes in types and quantities of vegetation for different buffer zones.

Beyond "bluespace" and "greenspace": A narrative review of possible health benefits from exposure to other natural landscapes.

Numerous studies have highlighted the physical and mental health benefits of contact with nature, typically in landscapes characterized by plants (i.e., "greenspace") and water (i.e., "bluespace"). However, natural landscapes are not always green or blue, and the effects of other landscapes are worth attention. This narrative review attempts to overcome this limitation of past research. Rather than focusing on colors, we propose that natural landscapes are composed of at least one of three components: (1) plants (e.g., trees, flowering plants, grasses, sedges, mosses, ferns, and algae), (2) water (e.g., rivers, canals, lakes, and oceans), and/or (3) rocks and minerals, including soil. Landscapes not dominated by plants or liquid-state water include those with abundant solid-state water (e.g., polar spaces) and rocks or minerals (e.g., deserts and caves). Possible health benefits of solid-state water or rock/mineral dominated landscapes include both shorter-term (e.g., viewing images) and longer-term (e.g., living in these landscapes) exposure durations. Reported benefits span improved emotional and mental states and medical treatment resources for respiratory conditions and allergies. Mechanisms underlying the health benefits of exposure consist of commonly discussed theories in the "greenspace" and "bluespace" literature (i.e., instoration and restoration) as well as less discussed pathways in that literature (i.e., post-traumatic growth, self-determination, supportive environment theory, and place attachment). This is the first review to draw attention to the potential salutogenic value of natural landscapes beyond "greenspace" and "bluespace." It is also among the first to highlight the limitations and confusion that result from classifying natural landscapes using color. Since the extant literature on natural landscapes - beyond those with abundant plants or liquid-state water - is limited in regard to quantity and quality, additional research is needed to understand their restorative potential and therapeutic possibilities.

Satisfaction with urban trees associates with tree canopy cover and tree visibility around the home.

Many world cities want to expand the number of urban trees. How this expansion occurs should consider what people expect from trees based on how they experience and perceive these trees. Therefore, we need a better understanding of how people perceptually respond to urban tree abundance. This research examined whether people's satisfaction with urban trees and satisfaction with the management of those trees were related to objective measures of greenery such as the Normalized Difference Vegetation Index (NDVI), percent tree canopy cover, and the Viewshed Greenness Visibility Index (VGVI) for trees. We used a demographically and geographically representative survey of 223 residents in Toronto, Canada, and calculated NDVI, canopy cover, and VGVI at three neighbourhood sizes. We analysed the data using generalized linear regression. We found that canopy cover and VGVI had a positive association with satisfaction with urban trees. The associations were comparatively stronger at larger neighbourhood scales than at smaller scales. There were no statistically significant associations with NDVI or satisfaction with the management of urban trees.

Nature's contributions in coping with a pandemic in the 21st century: A narrative review of evidence during COVID-19.

While COVID-19 lockdowns have slowed coronavirus transmission, such structural measures also have unintended consequences on mental and physical health. Growing evidence shows that exposure to the natural environment (e.g., blue-green spaces) can improve human health and wellbeing. In this narrative review, we synthesized the evidence about nature's contributions to health and wellbeing during the first two years of the COVID-19 pandemic. We found that during the pandemic, people experienced multiple types of nature, including both outdoors and indoors. Frequency of visits to outdoor natural areas (i.e., public parks) depended on lockdown severity and socio-cultural contexts. Other forms of nature exposure, such as spending time in private gardens and viewing outdoor greenery from windows, may have increased. The majority of the evidence suggests nature exposure during COVID-19 pandemic was associated with less depression, anxiety, stress, and more happiness and life satisfaction. Additionally, nature exposure was correlated with less physical inactivity and fewer sleep disturbances. Evidence was mixed regarding associations between nature exposure and COVID-related health outcomes, while nature visits might be associated with greater rates of COVID-19 transmission and mortality when proper social distancing measures were not maintained. Findings on whether nature exposure during lockdowns helped ameliorate health inequities by impacting the health of lower-socioeconomic populations more than their higher-socioeconomic counterparts for example were mixed. Based on these findings, we argue that nature exposure may have buffered the negative mental and behavioral impacts of lockdowns during the COVID-19 pandemic. Recovery and resilience during the current crises and future public health crises might be improved with nature-based infrastructure, interventions, designs, and governance.

Greenspace and park use associated with less emotional distress among college students in the United States during the COVID-19 pandemic.

The COVID-19 pandemic has negatively affected many people's psychological health. Impacts may be particularly severe among socially vulnerable populations such as college students, a group predisposed to mental health problems. Outdoor recreation and visits to greenspaces such as parks offer promising pathways for addressing the mental health challenges associated with COVID-19. During the early stages of the pandemic (March-May 2020), we surveyed 1280 college students at four large public universities across the United States (U.S.) to assess how, and why, outdoor recreation and park use changed since the emergence of COVID-19. We also measured students' self-reported levels of emotional distress (a proxy for psychological health) and assessed potential demographic and contextual correlates of distress, including county-level per capita park area and greenness, using generalized linear models. We found that 67% of students reported limiting outdoor activities and 54% reported reducing park use during the pandemic. Students who reduced their use of outdoor spaces cited structural reasons (e.g., lockdowns), concerns about viral transmission, and negative emotions that obstructed active lifestyles. Students who maintained pre-pandemic park use levels expressed a desire to be outdoors in nature, often with the explicit goal of improving mental and physical health. Emotional distress among students was widespread. Models showed higher levels of emotional distress were associated with reducing park use during the pandemic and residing in counties with a smaller area of parks per capita. This study of U.S. college students supports the value of park-based recreation as a health promotion strategy for diverse populations of young adults during a time of crisis.

Estimating multiple greenspace exposure types and their associations with neighbourhood premature mortality: A socioecological study.

BACKGROUND: Greenspace exposures are often measured using single exposure metrics, which can lead to conflicting results. Existing methodologies are limited in their ability to estimate greenspace exposure comprehensively. We demonstrate new methods for estimating single and combined greenspace exposure metrics, representing multiple exposure types that combine impacts at various scales. We also investigate the association between those greenspace exposure types and premature mortality. METHODS: We used geospatial data and spatial analytics to model and map greenspace availability, accessibility and eye-level visibility exposure metrics. These were harmonised and standardised to create a novel composite greenspace exposure index (CGEI). Using these metrics, we investigated associations between greenspace exposures and years of potential life lost (YPLL) for 1673 neighbourhoods applying spatial autoregressive models. We also investigated the variations in these associations in conjunction with levels of socioeconomic deprivation based on the index of multiple deprivations. RESULTS: Our new CGEI metric provides the opportunity to estimate spatially explicit total greenspace exposure. We found that a 1-unit increase in neighbourhood CGEI was associated with approximately a 10-year reduction in YPLL. Meaning a 0.1 increment or 10% increase in the CGEI is associated with an approximately one year lower premature mortality value. A single 1-unit increase in greenspace availability was associated with a YPLL reduction of 9.8 years, whereas greenness visibility related to a reduction of 6.14 years. We found no significant association between greenspace accessibility and YPLL. Our results further identified divergent trends in the relations between greenspace exposure types (e.g. availability vs. accessibility) and levels of socioeconomic deprivation (e.g. least vs. most). CONCLUSION: Our methods and metrics provide a novel approach to the assessment of multiple greenspace exposure types, and can be linked to the broader exposome framework. Our results showed that a higher composite greenspace exposure is associated with lower premature mortality.

Walkability and Greenness Do Not Walk Together: Investigating Associations between Greenness and Walkability in a Large Metropolitan City Context.

BACKGROUND: The existing environment literature separately emphasizes the importance of neighborhood walkability and greenness in enhancing health and wellbeing. Thus, a desirable neighborhood should ideally be green and walkable at the same time. Yet, limited research exists on the prevalence of such "sweet spot" neighborhoods. We sought to investigate this question in the context of a large metropolitan city (i.e., Sydney) in Australia. METHODS: Using suburb level normalized difference vegetative index (NDVI), percentage urban greenspace, Walk Score® (Walk Score, Seattle, WA, USA), and other data, we explored the global and local relationships of neighborhood-level greenness, urban green space (percent park area) with walkability applying both non-spatial and spatial modeling. RESULTS: We found an overall negative relationship between walkability and greenness (measured as NDVI). Most neighborhoods (represented by suburbs) in Sydney are either walkable or green, but not both. Sweet spot neighborhoods that did exist were green but only somewhat walkable. In addition, many neighborhoods were both less green and somewhat walkable. Moreover, we observed a significant positive relationship between percentage park area and walkability. These results indicate walkability and greenness have inverse and, at best, mixed associations in the Sydney metropolitan area. CONCLUSIONS: Our analysis indicates an overall negative relationship between greenness and walkability, with significant local variability. With ongoing efforts towards greening Sydney and improving walkability, more neighborhoods may eventually be transformed into becoming greener and more walkable.

Modelling and mapping eye-level greenness visibility exposure using multi-source data at high spatial resolutions.

The visibility of natural greenness is associated with several health benefits along multiple pathways, including stress recovery and attention restoration mechanisms. However, existing methodologies are inadequate for capturing eye-level greenness visibility exposure at high spatial resolutions for observers located on the ground. As a response, we developed an innovative methodological approach to model and map eye-level greenness visibility exposure for 5 m interval locations within a large study area. We used multi-source spatial data and applied viewshed analysis in conjunction with a distance decay model to compute a novel Viewshed Greenness Visibility Index (VGVI) at more than 86 million observer locations. We compared our eye-level visibility exposure map with traditional top-down greenness exposure metrics such as Normalised Differential Vegetation Index (NDVI) and a Street view based Green View Index (SGVI). Furthermore, we compared greenness visibility at street-only locations with total neighbourhood greenness visibility. We found strong to moderate correlations (r = 0.65-0.42, p < 0.05) between greenness visibility and mean NDVI, with a decreasing trend in correlation strength at increasing buffer distances from observer locations. Our findings suggest that top-down and eye-level measurements of greenness are two distinct metrics for assessing greenness exposure. Additionally, VGVI showed a strong correlation (r = 0.481, p < 0.01) with SGVI. Although the new VGVI has good agreement with existing street view based measures, we found that street-only greenness visibility values are not wholly representative of total neighbourhood visibility due to the under-representation of visible greenness in locations such as backyards and community parks. Our new methodology overcomes such underestimations, is easily transferable, and offers a computationally efficient approach to assessing eye-level greenness exposure.

Noncommunicable Diseases, Park Prescriptions, and Urban Green Space Use Patterns in a Global South Context: The Case of Dhaka, Bangladesh.

Urban green space use is often associated with improved physical and mental health and lower noncommunicable disease (NCDs) burdens. Factors that influence green space visits have been documented in cities of the Global North, but evidence of urban green space use patterns for cities in the Global South is scarce. The aim of this study is to investigate factors influencing urban green space use patterns in Dhaka, Bangladesh, a megacity of the Global South, with a particular focus on how poor health condition and healthcare professionals' prescriptions to exercise outdoors (park prescriptions-ParkRx) impact the green space use of middle-aged adults. We collected green space characteristics and use factors (i.e., availability, accessibility, attractiveness, and attachment), health condition, ParkRx, and urban green space use intensity (i.e., frequency and duration) via a self-reported questionnaire from 169 middle-aged residents of Dhaka. We used multivariate modeling to estimate the association of green space characteristics, health condition, and ParkRx with use intensity. We further applied a mediation analysis to determine the influence of ParkRx on the relationship between residents' poor health conditions and use intensity. We found that green space availability and accessibility did not significantly influence use intensity, but attractiveness was negatively associated with use intensity. Green space use intensity was significantly and positively associated with attachment to the green space, poor health condition (i.e., having noncommunicable diseases), and ParkRx. ParkRx significantly mediated the relationship between health condition and use intensity. We observed limited supply, poor access, and low attractiveness when studying the urban green spaces in Dhaka, but these qualities did not affect use intensity, as found in many case studies in the Global North. In contrast, urban green space use intensity in our case study is mostly dependent on poor health condition and park prescriptions.

Spatial dimensions of the influence of urban green-blue spaces on human health: A systematic review.

BACKGROUND: There is an increasing volume of literature investigating the links between urban environments and human health, much of which involves spatial conceptualisations and research designs involving various aspects of geographical information science. Despite intensifying research interest, there has been little systematic investigation of pragmatic methodological concerns, such as how studies are realised in terms of the types of data that are gathered and the analytical techniques that are applied, both of which have the potential to impact results. The aim of this systematic review is, therefore, to understand how spatial scale, datasets, methods, and analytics are currently applied in studies investigating the relationship between green and blue spaces and human health in urban areas. METHOD: We systematically reviewed 93 articles following PRISMA protocol, extracted information regarding different spatial dimensions, and synthesised them in relation to various health indicators. RESULTS AND DISCUSSION: We found a preponderance of the use of neighbourhood-scale in these studies, and a majority of the studies utilised land-use and vegetation indices gleaned from moderate resolution satellite imagery. We also observed the frequent adoption of fixed spatial units for measuring exposure to green and blue spaces based on physical proximity, typically ranging between 30 and 5000 m. The conceptual frameworks of the studies (e.g., the focus on physical vs. mental health or the definition of exposure to green space) were found to have an influence on the strength of association between exposure and health outcomes. Additionally, the strength and significance of associations also varied by study design, something which has not been considered systematically. CONCLUSION: On the basis of our findings, we propose a set of recommendations for standardised protocols and methods for the evaluation of the impact of green-blue spaces on health. Our analysis suggests that future studies should consider conducting analyses at finer spatial scales and employing multiple exposure assessment methods to achieve a comprehensive and comparable evaluation of the association between greenspace and health along multiple pathways.

Carbon dioxide emission and bio-capacity indexing for transportation activities: A methodological development in determining the sustainability of vehicular transportation systems.

CO2 emissions from urban traffic are a major concern in an era of increasing ecological disequilibrium. Adding to the problem net CO2 emissions in urban settings are worsened due to the decline of bio-productive areas in many cities. This decline exacerbates the lack of capacity to sequestrate CO2 at the micro and meso-scales resulting in increased temperatures and decreased air quality within city boundaries. Various transportation and environmental strategies have been implemented to address traffic related CO2 emissions, however current literature identifies difficulties in pinpointing these critical areas of maximal net emissions in urban transport networks. This study attempts to close this gap in the literature by creating a new lay-person friendly index that combines CO2 emissions from vehicles and the bio-capacity of specific traffic zones to identify these areas at the meso-scale within four ranges of values with the lowest index values representing the highest net CO2 levels. The study used traffic volume, fuel types, and vehicular travel distance to estimate CO2 emissions at major links in Dhaka, Bangladesh's capital city's transportation network. Additionally, using remote-sensing tools, adjacent bio-productive areas were identified and their bio-capacity for CO2 sequestration estimated. The bio-productive areas were correlated with each traffic zone under study resulting in an Emission Bio-Capacity index (EBI) value estimate for each traffic node. Among the ten studied nodes in Dhaka City, nine had very low EBI values, correlating to very high CO2 emissions and low bio-capacity. As a result, the study considered these areas unsustainable as traffic nodes going forward. Key reasons for unsustainability included increasing use of motorized traffic, absence of optimized signal systems, inadequate public transit options, disincentives for fuel free transport (FFT), and a decline in bio-productive areas.

Association of catalase gene polymorphisms with catalase activity and susceptibility to systemic lupus erythematosus in the Suez Canal area, Egypt.

The present study evaluated the relationship of genetic variants in both promoter (-262 C/T) and in exonic (389 C/T) regions of the catalase (CAT) gene to CAT activity and risk of systemic lupus erythematosus (SLE) in Suez Canal-area patients. CAT gene polymorphisms were assessed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CAT activity was measured by using a spectrophotometer. We compared the frequencies of CAT 389 C/T and -262 C/T polymorphic variants between SLE patients (n = 103) and healthy controls (n = 103). CAT 389 C/T is associated with SLE susceptibility, with the T allele being significantly more frequent among SLE patients than healthy controls. There was no association, however, between CAT activity and genotypes of 389 C/T. We did not observe significant differences in the prevalence of CAT -262 C/T polymorphic variants in SLE patients and controls, however, we found that patients with the CAT -262 CT and TT genotypes had low CAT activity, and these genotypes showed a significant association with thrombocytopaenia, leukopaenia and the presence of anti-snRNP in SLE patients. In conclusion, the present study supports the notion of in vivo oxidative stress in SLE as indicated by the decrease in CAT activity. The allelic variations in the CAT gene -262 are more likely to affect the expression or the function of the enzyme. Since CAT may be pathogenetically linked to SLE, and owing to its free-radical origin, it appears reasonable to target lipid peroxidation by dietary and/or pharmacological antioxidants.

Detection of circulating antierythropoietin antibodies in patients with end stage renal disease on regular hemodialysis.

Recombinant human erythropoietin (rHuEPO) has been successfully and safely used to treat anemia in patients with end stage renal disease (ESRD). The safety profile of rHuEPO had been considered to be excellent with possible exception of hypertension and increased risk of dialysis access thrombosis. Recently, antibody-mediated pure red cell aplasia associated with administration of rHuEPO has been identified as a cause of major concern; we aimed to detect and evaluate the presence of anti-EPO antibodies in patients with ESRD on regular dialysis who are using rHuEPO. Serum anti-EPO antibodies were detected by enzyme-linked immunosorbant assay technique in a total of 90 patients who are currently on regular hemodialysis and using rHuEPO alpha subcutaneously for more than 6 months. All patients were subjected to full history taking and clinical examination. Complete blood count, reticulocytes count, serum creatinine, blood urea, serum albumin, serum ferritin, and hepatitis markers were performed for all patients. Our results showed that 35 patients (38.9%) had the anti-EPO antibodies in their blood, while 55 patients (61.1%) did not have the circulating antibodies. The mean hemoglobin (Hb) level was significantly lower in the antibody positive group (8.8 g/dl +/- 1.35) than in the antibody negative group (9.42 g/dl +/- 1.32) (P = 0.000). The reticulocytes count was also significantly much lower in the patients who had anti-EPO antibodies with mean of (1.99 +/- 1.14) vs. (3.15 +/- 0.89) in the antibody negative (P = 0.000). The dose of EPO administrated in both studied groups was insignificantly different. The incidence of anti-EPO antibodies is high in ESRD patients on maintenance hemodialysis. Its presence is associated with increased incidence of anemia possibly due to immune-mediated inhibition of erythropoiesis as evidenced by reticulocytopenia.

Biochemical dynamics and hypocholesterolemic action of Hibiscus sabdariffa (Karkade).

Male albino rats were fed on a mixture of cholesterol and cholic acid for 12 weeks to induce hypercholesterolemia, then Karkade was administered at 5 and 10% for 9 weeks to evaluate its hypocholesterolemic and hypolipemic effect. The experimental parameters include total lipids, cholesterol, triglycerides and phospholipids. Liver and kidney functions were also investigated in normal, hypo- and hypercholesterolemic rats administered Karkade. A remarkable progress (lowering effect) in the level of different lipid fractions was noticed in spite of the continued cholesterol and cholic acid loading during the treatment. However, blood phospholipids were increased after Karkade administration. Hypercholesterolemia has resulted in an effect on the activity of liver and kidney functions. Therefore, the measurement of serum enzyme activity has provided a useful tool for hepatic recovery. Although the administration of Karkade at 5 and 10% induced a significant decrease in the activity of serum GOT and serum GPT, alkaline and acid phosphatase as well as total serum protein, the values nearly returned to the initial levels after 9 weeks of Karkade administration.

Metabolic effects of licorice roots (Glycyrrhiza glabra) on lipid distribution pattern, liver and renal functions of albino rats. MS.

The biochemical activity of licorice roots was investigated by administrating it to hypercholesterolaemic rats at two different doses. High cholesterol level in the serum and most organs of hypercholesterolaemic rats was accompanied by high levels of triglycerides and total lipids but low one of phospholipids. The hypocholesterolaemic action of licorice roots was accompanied by hypolipaemic action but higher level of phospholipids in the rat serum and most organs. The results showed that while the high cholesterol level in the rat serum has impairing effects on liver and renal functions, the licorice administered to these rats has a counteracting action i.e. it can improve the impaired function of both liver and p4f1ey, It has also a hypoglycaemic action.