11453581
Proinflammatory effects of oxidative stress in chronic kidney disease: role of additional angiotensin II blockade.
Oxidative stress plays an important role in causing progressive chronic kidney disease (CKD). We examined the influence of add-on ANG II receptor blockade administered as losartan (50 mg/day for 1 mo) on oxidative stress and proinflammatory state of the kidney in patients with CKD. All subjects were taking an angiotensin-converting enzyme inhibitor plus other antihypertensive agents. Oxidative stress to lipids and proteins was measured by an HPLC assay for malondialdehyde (MDA) and carbonyl concentration, respectively. Urinary inflammation was measured by monocyte chemotactic protein-1 (MCP-1) excretion rate. The etiology of CKD was type 2 diabetes mellitus in 12 and glomerulonephritis in 4 patients. There was no change in proteinuria or 24-h ambulatory blood pressure (BP) with add-on ANG II receptor blockade with losartan therapy. Before losartan therapy, urinary protein and albumin oxidation were 99 and 71% higher, respectively, compared with in plasma (P < 0.05). There was a 35% reduction in urinary oxidized albumin with add-on losartan therapy (P = 0.036). Urinary and plasma MDA were elevated compared with age-matched controls. Urinary MDA was significantly reduced from 4.75 +/- 3.23 to 3.39 +/- 2.17 micromol/g creatinine with add-on losartan therapy. However, plasma MDA or oxidized proteins did not change in response to additional ANG II blockade. A good correlation was seen between the change in urinary oxidized albumin and MCP-1 levels (r = 0.61, P = 0.012). These data demonstrate that oxidative damage to urinary protein and lipids can be reduced with additional ANG II receptor blockade, independently of reductions in proteinuria or BP. Urinary measurements of markers of oxidative damage to lipids and proteins appear to be more sensitive than plasma measurements in patients with CKD. The significant association of the change in urinary MCP-1 with a reduction in oxidative stress supports the role of the redox state in the kidney with renal fibrosis and progressive kidney damage.
207670106
Competing Risk Factor Analysis of End-Stage Renal Disease and Mortality in Chronic Kidney Disease
Background: Death and dialysis are competing outcomes in patients with chronic kidney disease (CKD). The factors associated with end-stage renal disease (ESRD) versus death in this population are unknown. The purpose of our study was to evaluate the competing risk of ESRD versus mortality and to evaluate the risk factors associated with these two outcomes. Methods: We prospectively recruited 220 consecutive patients at a Veterans Administration Medical Center attending a renal clinic who met the definition of CKD (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 or urine protein/creatinine ratio of >0.22 g/g). Using age, race, proteinuria, eGFR, systolic blood pressure, and coronary artery disease as predictors, we calculated the competing end-points of ESRD or death using a competing Cox regression model. Results: The cumulative incidence for ESRD was 17.6% and death 18.5% during follow-up that lasted up to 7 years. ESRD was predicted by younger age (hazard ratio (HR) 0.91/year), black race (HR 2.75), higher systolic blood pressure (HR 1.02/mm Hg), proteinuria (HR 1.37/log urine protein/creatinine ratio) and low eGFR (0.014/log eGFR ml/min/1.73 m2). Death was predicted by older age (HR 1.07/year), lower eGFR (HR 0.43/log eGFR ml/min/1.73 m2), proteinuria (HR 1.26/log urine protein/creatinine ratio) and coronary artery disease (HR 2.52). The coefficients were statistically different for age (p < 0.001), log eGFR (p < 0.001) and systolic blood pressure (p = 0.04) for ESRD and death outcomes. Conclusions: The risk for mortality is similar to the risk of ESRD in the CKD population of veterans seen by nephrologists. Risk factors for ESRD and death appear to differ in this population. Certain clinical and demographic factors may discriminate between the end-points of death or dialysis and may influence decisions about planning for ESRD.
191311
Assessment of iothalamate plasma clearance: duration of study affects quality of GFR.
BACKGROUND AND OBJECTIVES
Measurement of GFR is important for the management of chronic kidney disease (CKD). Although bolus administration of radiocontrast agents is commonly used to measure GFR, the optimal duration of sampling to assess their plasma clearance is unknown. The purpose of this study was to evaluate whether the duration of plasma sampling influences precision and estimation of GFR.


DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
GFR was measured by sampling plasma 12 times over 5 h in 56 patients with CKD (mean age 64 yr, 98% men, 79% Caucasian, 34% diabetics, estimated GFR 31.8 +/- 14.2 ml/min/1.73 m(2)). In a subset of 12 patients we measured GFR by sampling plasma 17 times over 10 h.


RESULTS
Short sampling intervals considerably overestimated GFR measured using total plasma iothalamate clearance, especially in larger patients. In the higher estimated GFR group (>30 ml/min/1.73 m(2)), the 5-h GFR was 17% higher and 2-h GFR 54% higher compared with the 10-h GFR, which averaged 40.3 ml/min/1.73 m(2). In the lower estimated GFR group (<30 ml/min/1.73 m(2)), the 5-h GFR was 36% higher and 2-h GFR 126% higher compared with the 10-h GFR, which averaged 22.2 ml/min/1.73 m(2). Short sampling duration also reduced the precision of the estimated GFR from 1.67% for 10-h GFR, to 3.48% for 5-h GFR, and to 7.07% for 2-h GFR.


CONCLUSIONS
GFR measured over a longer duration with multiple plasma samples spanning the distribution and elimination phases may improve precision and provide a better measure of renal function.
40070884
Relative plasma volume monitoring for identifying volume-sensitive and -resistant hypertension.
The measurement and management of volume state among long-term dialysis patients has not received much attention. Recent reports suggest that relative plasma volume monitoring may be useful in identifying patients who have volume excess. Among patients who have evidence of excess volume by relative plasma volume monitoring, excess volume removal leads to improvement in interdialytic ambulatory blood pressure. Implementation of this technique can result in improved classification of patients into volume-sensitive and -resistant categories and therefore improve the management of hypertension.
35998479
Exploring the paradoxical relationship of hypertension with mortality in chronic hemodialysis.
Hypertension is seen in 85% of patients on hemodialysis (HD) in the United States. Although it is amply clear that high blood pressure (BP) has a continuous, graded, and etiologically significant relationship with cardiovascular outcomes in the general population, studies in HD patients have found an inverse relationship between high BP and outcomes. Thus, those patients with high BP have a lower mortality compared to those with low BP. It is intellectually troublesome to find such an association because high BP, which was such an important risk factor for cardiovascular disease before onset of dialysis suddenly, becomes a protective factor. In patients with chronic kidney disease who are not yet on HD, we strive to lower BP more aggressively than what we target those with uncomplicated essential hypertension. If these observations—‘‘reverse epidemiology’’ or ‘‘risk factor paradox’’—are etiologically significant, should we be complacent about treating high BP in HD? The objective of this analysis is to review the data to explain these apparently troublesome observations. POOR ASSESSMENT OF BP: REGRESSION DILUTION BIAS
24249726
Regulation of circadian blood pressure: from mice to astronauts.
PURPOSE OF REVIEW
Circadian variation is commonly seen in healthy people; aberration in these biological rhythms is an early sign of disease. Impaired circadian variation of blood pressure (BP) has been shown to be associated with greater target organ damage and with an elevated risk of cardiovascular events independent of the BP load. The purpose of this review is to examine the physiology of circadian BP variation and propose a tripartite model that explains the regulation of circadian BP.


RECENT FINDINGS
The time-keeper in mammals resides centrally in the suprachiasmatic nucleus. Apart from this central clock, molecular clocks exist in most peripheral tissues including vascular tissue and the kidney. These molecular clocks regulate sodium balance, sympathetic function and vascular tone. A physiological model is proposed that integrates our understanding of molecular clocks in mice with the circadian BP variation among humans. The master regulator in this proposed model is the sleep-activity cycle. The equivalents of peripheral clocks are endothelial and adrenergic functions. Thus, in the proposed model, the variation in circadian BP is dependent upon three major factors: physical activity, autonomic function, and sodium sensitivity.


SUMMARY
The integrated consideration of physical activity, autonomic function, and sodium sensitivity appears to explain the physiology of circadian BP variation and the pathophysiology of disrupted BP rhythms in various conditions and disease states. Our understanding of molecular clocks in mice may help to explain the provenance of blunted circadian BP variation even among astronauts.
13914994
Noninvasive positive pressure ventilation in acute respiratory failure due to COPD vs other causes: Effectiveness and predictors of failure in a respiratory ICU in North India
Objectives To determine the effectiveness of noninvasive positive pressure ventilation (NIPPV), and the factors predicting failure of NIPPV in acute respiratory failure (ARF) due to chronic obstructive pulmonary disease (COPD) versus other causes of ARF. Patients and methods This was a prospective observational study and all patients with ARF requiring NIPPV over a one-and-a-half year period were enrolled in the study. We recorded the etiology of ARF and prospectively collected the data for heart rate, respiratory rate, arterial blood gases (pH, partial pressure of oxygen in the arterial blood [PaO2], partial pressure of carbon dioxide in arterial blood [PaCO2]) at baseline, one and four hours. The patients were further classified into two groups based on the etiology of ARF as COPD–ARF and ARF due to other causes. The primary outcome was the need for endotracheal intubation during the intensive care unit (ICU) stay. Results During the study period, 248 patients were admitted in the ICU and of these 63 (25.4%; 24, COPD–ARF, 39, ARF due to other causes; 40 male and 23 female patients; mean [standard deviation] age of 45.7 [16.6] years) patients were initiated on NIPPV. Patients with ARF secondary to COPD were older, had higher APACHE II scores, lower respiratory rates, levels compared to other causes of ARF. After one hour there was lower pH and higher PaCO2 levels with increase a significant decrease in respiratory rate and heart rate and decline in PaCO2 levels in patients successfully managed with NIPPV. However, there was no in pH and PaO2 difference in improvement of clinical and blood gas parameters between the two groups except at one hour which was significantly the rate of decline of pH at one and four hours and PaCO2 faster in the COPD group. NIPPV failures were significantly higher in ARF due to other causes (15/39) than in ARF–COPD (3/24) (p = 0.03). The mean ICU and hospital stay and the hospital mortality were similar in the two groups. In the multivariate logistic regression model (after and adjusting for gender, APACHE II scores and improvement in respiratory rate, pH, PaO2 at one hour) only the etiology of ARF, ie, ARF–COPD, was associated with a decreased PaCO2 risk of NIPPV failure (odds ratio 0.23; 95% confidence interval, 0.58–0.9). Conclusions NIPPV is more effective in preventing endotracheal intubation in ARF due to COPD than other causes, and the etiology of ARF is an important predictor of NIPPV failure.
35489466
Aspergillus hypersensitivity and allergic bronchopulmonary aspergillosis in patients with bronchial asthma: systematic review and meta-analysis.
BACKGROUND
The prevalence of Aspergillus hypersensitivity (AH) and allergic bronchopulmonary aspergillosis (ABPA) in bronchial asthma is reported differently in various studies.


OBJECTIVE
To determine the prevalence of AH and ABPA in asthma using a systematic review.


METHODS
We searched the MEDLINE and EMBASE databases for studies published from 1965 to 2008 and included studies that report the prevalence of AH/ABPA in asthma. We calculated the proportions with 95% confidence interval (CI) to assess the prevalence of AH/ABPA in the individual studies and pooled the results using a random effects model.


RESULTS
Our search yielded 21 eligible studies. The prevalence of AH in bronchial asthma was 28% (95%CI 24-34), and was higher with an intradermal test vs. a prick test (28.7% vs. 24.8%, P = 0.002), but did not vary with the type of antigen used (indigenous or commercial). The prevalence of ABPA in bronchial asthma and Aspergillus-hypersensitive bronchial asthma was respectively 12.9% (95%CI 7.9-18.9) and 40% (95%CI 27-53). There was a wide variation in the criteria used for the diagnosis of ABPA. There was significant statistical heterogeneity assessed by the I(2) test and Cochran Q statistic in all the outcomes.


CONCLUSIONS
There is a high prevalence of AH and ABPA in patients with bronchial asthma. Careful screening should therefore be performed in all patients with bronchial asthma. Intradermal tests are more sensitive than prick tests for the diagnosis of AH. Finally, there is a need to adopt a uniform methodology and criteria for the diagnosis of AH/ABPA.
12257571
Protection against ultraviolet B radiation-induced effects in the skin of SKH-1 hairless mice by a polyphenolic fraction isolated from green tea.
In prior studies we and others have shown that oral feeding of a polyphenolic fraction isolated from green tea (GTP) or water extract of green tea affords protection against ultraviolet B (UVB) radiation-induced carcinogenesis in SKH-1 hairless mice (Wang et al., Carcinogenesis 12, 1527-1530, 1991). It is known that exposure of murine skin to UVB radiation results in cutaneous edema, depletion of the antioxidant-defense system and induction of ornithine decarboxylase (ODC) and cyclooxygenase activities. In this study we assessed the protective effect of GTP on these UVB radiation-caused changes in murine skin. Oral feeding of 0.2% GTP (wt/vol) as the sole source of drinking water for 30 days to SKH-1 hairless mice followed by irradiation with UVB (900 mJ/cm2) resulted in significant protection against UVB radiation-caused cutaneous edema (P < 0.0005) and depletion of the antioxidant-defense system in epidermis (P < 0.01-0.02). The oral feeding of GTP also resulted in significant protection against UVB radiation-caused induction of epidermal ODC (P < 0.005-0.01) and cyclooxygenase activities (P < 0.0001) in a time-dependent manner. Our data indicate that the inhibition of UVB radiation-caused changes in these markers of tumor promotion in murine skin by GTP may be one of the possible mechanisms of chemopreventive effects associated with green tea against UVB-induced tumorigenesis. The results of this study suggest that green tea, specifically polyphenols present therein, may be useful against inflammatory responses associated with the exposure of skin to solar radiation.
41765492
Effects of magnesium taurate on the onset and progression of galactose-induced experimental cataract: in vivo and in vitro evaluation.
Cataract, a leading cause of blindness, is characterized by lenticular opacities resulting from denaturation of lens proteins due to activation of calcium-dependent enzyme, calpain. Magnesium (Mg(2+)) plays an important role not only in maintaining a low lenticular calcium (Ca(2+)) and sodium concentration but also in preserving the lens redox status. Taurine has also been shown to reduce lenticular oxidative stress. Present study evaluated the anticataract effects of magnesium taurate in vivo and in vitro. Among the five groups of 9 Sprague Dawley rats each, two groups received 30% galactose diet with topical (GDMT) or oral treatment (GDMO) with magnesium taurate. Two groups received 30% galactose diet with topical (GDT) or oral vehicle (GDO). Remaining 1 group received normal diet (ND). Weekly slit lamp examination was done during 21 days experimental period and then all rats were sacrificed; Ca/Mg ratio and antioxidant parameters including reduced glutathione (GSH), catalase and superoxide dismutase (SOD) activities were measured in the isolated lenses using ELISA. In the in vitro study, 2 groups of 10 normal rat lenses were incubated in Dulbecco's Modified Eagle's Medium (DMEM) with galactose while 1 similar group was incubated in DMEM without galactose. In one of the groups, galactose containing medium was supplemented with magnesium taurate. After 48 h of incubation, lenses were photographed and Ca(2+)/Mg(2+) ratio and antioxidant parameters were measured as for in vivo study. The in vivo study, at the end of experimental period, demonstrated delay in the development of cataract with a mean opacity index of 0.53 ± 0.04 and 0.51 ± 0.03 in GDMO (p < 0.05 versus GDO) and GDMT (p < 0.01 versus GDT) respectively. Histopathological grading showed a lower mean value in treated groups, however, the differences from corresponding controls were not significant. Lenticular Ca(2+)/Mg(2+) ratio with a mean value of 1.20 ± 0.26 and 1.05 ± 0.26 in GDMO and GDMT was significantly lower than corresponding controls (p < 0.05) and in GDMT no significant difference was observed from ND. Lenticular GSH and catalase activities were significantly lower and SOD activity was significantly higher in all galactose fed groups. However, in GDMT, GSH and catalase were significantly higher than corresponding control with mean values of 0.96 ± 0.30 μmol/gm lens weight and 56.98 ± 9.86 μmol/g lens protein respectively (p < 0.05 for GSH and p < 0.01 for catalase). SOD activity with mean values of 13.05 ± 6.35 and 13.27 ± 7.61 units/mg lens protein in GDMO and GDMT respectively was significantly lower compared to corresponding controls (p < 0.05) signifying lesser upregulation of SOD due to lesser oxidative stress in treated groups. In the in vitro study, lenses incubated in magnesium taurate containing medium showed less opacity and a lower mean Ca(2+)/Mg(2+) ratio of 1.64 ± 0.03, which was not significantly different from lenses incubated in DMEM without galactose. Lens GSH and catalase activities were restored to normal in lenses incubated in magnesium taurate containing medium. Both in vivo and in vitro studies demonstrated that treatment with magnesium taurate delays the onset and progression of cataract in galactose fed rats by restoring the lens Ca(2+)/Mg(2+) ratio and lens redox status.
11594402
Intraocular Pressure-Lowering Activity of Topical Application of Aegle Marmelos Fruit Extract in Experimental Animal Models
Aim: The present study was designed to evaluate the intraocular pressure (IOP)-lowering activity of topical application of the aqueous extract of Aegle marmelos fruit in experimental animal models. Materials and Methods: New Zealand white rabbits with normal and experimentally elevated IOP using water loading and steroid-induced models were included in this study. The IOP-lowering effect of A. marmelos fruit extract in rabbits with experimentally elevated IOP was also compared with that of timolol 0.25%. Results: In rabbits with normal IOP, the A. marmelos fruit extract at a concentration of 1% showed the maximum IOP-lowering effect with 22.81% reduction from baseline IOP. The maximum IOP reduction achieved in water loading and steroid-induced models with the same concentration of A. marmelos was 27.57 and 28.41% from baseline, respectively. The efficacy was comparable to that of timolol after 45 min of water loading in the water loading model, and during the first 2 h of treatment in the steroid-induced model. Conclusion: A. marmelos fruit extract showed significant IOP-lowering activity in experimental animal models.