PubMed Health⌕ Search

Biomedical subjects

Errol D Crook

Publications and source records attributed to Errol D Crook.

At least 19 recordsLinked to original sources
PubMed2006

The effects of blood pressure and lipid control on kidney allograft outcome.

Despite the improvement in short- and long-term kidney allograft survival in recent years, a significant number of grafts are lost because of chronic allograft nephropathy (CAN) or death secondary to cardiovascular disease (CVD). There is growing evidence that both hypertension and hyperlipidemia play important roles in the progression of CAN and CVD in kidney transplant recipients. Large, randomized, controlled studies to determine the optimal target levels for BP and serum lipids, as well as the choice of drug therapy, are lacking. However, based on the available data, we suggest that currently recommended target levels in non-transplant patients should also be used after transplantation. We believe that achieving these target levels for BP and serum lipids are of primary importance, and that the non-lipid-lowering effects of HMG-CoA reductase inhibitors might exert additional benefits in prolonging graft survival.

Blood Pressure↗
PubMed2006

Thiazolidinediones and progression of renal disease in patients with diabetes.

OBJECTIVE: Thiazolidinediones (TZDs) are used in the treatment of type 2 diabetes mellitus (T2DM) and appear to have beneficial effects on markers of cardiovascular or renal risk that are independent of glycemic control. We examined the effects of TZDs on renal survival in a predominantly black population with T2DM. METHODS: We performed a retrospective case-control study in patients with T2DM seen in our nephrology clinic in 2001 to 2002. Cases had T2DM and were on a TZD at presentation or for >or= 6 months over follow-up. Controls were matched for sex, age, duration of T2DM, and initial creatinine. Reaching end-stage renal disease (ESRD) was the primary end point. RESULTS: From 387 records, 43 cases (34 blacks, 31 females) and 106 controls (96 blacks, 83 females) were identified. The baseline characteristics were similar for both groups. Both groups had moderate renal disease (estimated glomerular filtration rate approximately 40-45 mL/min). Cases had lower systolic blood pressure over follow-up (p=.02), but there was no difference in glycemic control or use of insulin. Renal survival was better among cases (age- and gender-adjusted odds ratio for reaching ESRD 0.17 [95% confidence interval 0.03-0.8]; p=.03). When adjusted for systolic blood pressure over follow-up, the tendency for improved renal survival in cases remained but was no longer significant. CONCLUSION: We conclude that TZDs may protect against the progression of renal disease in T2DM. Prospective studies are required to determine the effects of TZDs on renal survival in T2DM.

Adult↗
PubMed2006

Glycemic control predicts diabetic extrarenal microvascular complications but not renal survival in patients with moderate to severe chronic kidney disease.

BACKGROUND: Control of blood pressure (BP) and blood glucose can slow the development of diabetic nephropathy (DN). However, BP control may be of relatively more importance than glycemic control on the progression of DN. OBJECTIVE: To determine the effects of glycemic control on renal survival in a predominantly African American diabetic population with moderate-to-severe renal disease. DESIGN: This was a retrospective chart review of all diabetic patients seen in an academic nephrology clinic in 2001 and 2002 for renal survival and its predictors and micro/macrovascular disease. The weighted mean glycosylated hemoglobin (GHb) over followup was determined. Mean GHb < or = 9 was defined as low, and GHb >9 was high. The effect of glycemic control on endpoints was determined by Cox proportional hazards and logistic regression. RESULTS: One hundred fifty-five diabetic patients (87.7% African American, mean creatinine =2.2 mg/dL) had sufficient GHb measurements. Compared to the high group (n=81), the low group (n=74) was significantly younger, had a shorter duration of diabetes, and worse renal function. No significant association of glycemic control with renal survival (ESRD) was seen. Glycemic control and the presence of DN were significantly related to extrarenal microvascular complications, independent of other factors. CONCLUSION: Glycosylated hemoglobin (GHb) is not a significant predictor of renal survival in patients with diabetes and moderate renal disease. However, glycemic control does predict extrarenal microvascular complications in this population. Therefore, good metabolic control remains important in patients with diabetes and renal disease.

Black or African American↗
PubMed2005

Transforming growth factor-beta1 regulation of laminin gamma1 and fibronectin expression and survival of mouse mesangial cells.

The transforming growth factor-beta (TGF-beta) 1 is a mediator of extracellular matrix (ECM) gene expression in mesangial cells and the development of diabetic glomerulopathy. Here, we investigate the effects of TGF-beta1 on laminin gamma1 and fibronectin polypeptide expression and cell survival in mouse mesangial cells (MES-13). TGF-beta1 (10 ng/ml) stimulates laminin-gamma1 and fibronectin expression approximately two-fold in a time-dependent manner (0-48 h). TGF-beta1 treatment also retards laminin-gamma1 mobility on SDS-gels, and tunicamycin, an inhibitor of the N-linked glycosylation, blocks the mobility shift. TGF-beta1 increases the binding of laminin gamma1 to WGA-agarose and the binding is abolished by tunicamycin suggesting that laminin gamma1 is modified by N-linked glycosylation. TGF-beta1 also elevates fibronectin glycosylation but its mobility is not altered. The degradation of laminin gamma1 and fibronectin proteins is reduced by their glycosylation. In addition, TGF-beta1 enhances mesangial cell viability and metabolic activities initially (0-24 h); however, eventually leads to cell death (24-48 h). TGF-beta1 elevates pro-apoptotic caspase-3 activity and decrease cell cycle progression factor cyclin D1 expression, which parallels cell death. These results indicate that TGF-beta1 plays an important role in ECM expression, protein glycosylation and demise of mesangial cells in the diabetic glomerular mesangium.

Animals↗
PubMed2005

Effects of steroids in focal segmental glomerulosclerosis in a predominantly African-American population.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is a common primary glomerulopathy in African Americans. Prolonged treatment with steroids is recommended for FSGS in those with nephrotic-range proteinuria, but strong evidence for this recommendation, especially in African-American adults, is lacking. We reviewed our experience with steroids in FSGS in a predominantly African-American cohort. METHODS: Patients with primary FSGS were identified and their charts were retrospectively reviewed for demographic data, characteristics of renal biopsy, blood pressure, and use of steroids. End-stage renal disease and doubling of creatinine were end-points. RESULTS: Seventy-two patients (65 African Americans) were identified with 48.3 months of follow-up. Patients receiving steroids (n=43) had higher urine protein excretion than those who did not. Seventeen patients reached end-stage renal disease and 26 doubled their creatinine concentration. Factors significant for renal survival on Cox proportional hazards model were initial creatinine level, severity of renal lesion, and blood pressure over the follow-up period. Treatment with steroids did not affect renal survival. About one third of patients receiving steroids developed complications consisting of diabetes (n=4) and greater than 5 kg weight gain (n=10). CONCLUSION: Renal function, severity of the renal lesion, and blood pressure determine renal survival in FSGS. A beneficial effect of steroids was not observed in this predominantly African-American adult cohort.

Adult↗
PubMed2005

Higher prevalence of anemia with diabetes mellitus in moderate kidney insufficiency: The Kidney Early Evaluation Program.

BACKGROUND: The Kidney Early Evaluation Program (KEEP 2.0) cross-sectional, community-based study, targeted individuals at increased risk for kidney disease and measured blood glucose, creatinine, and hemoglobin. METHODS: KEEP 2.0 screening data were used to determine the prevalence of anemia by level of kidney function and diabetes status. Estimated glomerular filtration rate (EGFR) was calculated using serum creatinine values, and categorized as > or =90, 60-89, 30-59 and <30 mL/min/1.73 m(2). Anemia was defined as hemoglobin <12 g/dL in men and in women aged >50 years, and <11 g/dL in women < or =50 years. Diabetes was defined as participant-reported diagnosis, fasting glucose >125 mg/dL, or nonfasting glucose >200 mg/dL. RESULTS: Data were available on 5380 participants screened from August 2000 through December 2001. Diabetes was present in 26.9% of participants, and anemia in 7.7%; 15.9% of participants had at least moderately reduced kidney function (EGFR <60 mL/min/1.73 m(2)). In participants with diabetes, anemia prevalence at the 4 levels of descending EGFR were 8.7%, 7.5%, 22.2%, and 52.4%, compared with 6.9%, 5.0%, 7.9%, and 50.0% in persons without diabetes. In a multivariable model, participants of non-white race/ethnicity, those with diabetes and those with EGFR <30 or 30-59 mL/min/1.73 m(2) had significantly increased odds of anemia. In addition, a significant sex-diabetes interaction was identified; odds of anemia were 4-fold greater in men than women with diabetes relative to sex-matched participants without diabetes. CONCLUSION: Diabetes was independently correlated with anemia, more so in men than women, and may be linked to premature expression of anemia in persons with moderate reductions in kidney function.

Adult↗
PubMed2005

Hepatitis C is a predictor of poorer renal survival in diabetic patients.

OBJECTIVE: Hepatitis C virus (HCV) is highly prevalent in the U.S. and worsens renal survival in some kidney diseases. We examined the effects of HCV on renal survival in diabetic patients with renal disease. RESEARCH DESIGN AND METHODS: HCV and diabetes status were noted in patients seen in our nephrology clinic in 2001 and 2002. Charts of diabetic patients were reviewed for demographics, blood pressure, renal function, medicines, the presence of HCV, and other factors at the initial visit and over follow-up. The effect of HCV on renal survival was determined by Cox proportional hazards, using end-stage renal disease (ESRD) as an end point. RESULTS: Of 1,127 patients, prevalence rates for HCV were higher in African Americans than non-African Americans (8.09 vs. 3.93%, respectively, P = 0.06), with African-American men having the highest prevalence rates (12.7%). The charts of 312 diabetic patients were reviewed. Over 80% were African American, as were 23 of 24 patients with HCV. Compared with non-HCV patients, HCV patients were younger, had higher diastolic blood pressure, and had lower BMI. HCV patients had significantly worse cumulative renal survival by Kaplan-Meier. On Cox proportional hazards analysis, HCV was a significant predictor of reaching ESRD independent of initial renal function, proteinuria, blood pressure, sex, race, presence of diabetic nephropathy, age, or duration of diabetes (odds ratio 3.49, 95% CI 1.27-9.57, P = 0.015). CONCLUSIONS: HCV is common in African Americans with diabetes and renal disease and is an independent risk factor for renal survival in this population. Prospective studies are necessary to confirm these observations.

Age of Onset↗
PubMed2004

Diabetic nephropathy in African-American patients.

Diabetic nephropathy (DN) is the number one cause of end-stage renal disease (ESRD) in the United States and is highly prevalent in African Americans. Since 1997, DN has been the number one cause of ESRD in African Americans. In African Americans, almost all DN is due to type 2 diabetes mellitus (T2DM), and nephropathy may affect female more than male patients. African Americans with T2DM are at increased risk for developing and having progression of DN. Glycemic control, development of albuminuria, family history of renal disease, and control of blood pressure are important risk factors for progression of DN. In addition, cigarette smoking, presence of hepatitis C, and use of thiazolinediones has an impact on renal survival in African Americans. Large vessel complications may be less frequent in African Americans with T2DM, when compared with white persons. Yet, cardiovascular disease and other microvascular complications are very common, and both are dependent on control of blood pressure. Achieving the recommended blood pressure of less than 130/80 mm Hg is essential but requires multiple antihypertensive medications, including an inhibitor of the renin-angiotensin system.

Adult↗
PubMed2004

Medical errors and the trainee: ethical concerns.

How medical errors are handled by individual physicians and hospital systems is a topic of considerable interest. In teaching hospitals, medical students and house officers often observe and commit mistakes. Commission of a mistake is associated with serious emotional turmoil and uncertainty among trainees as well as experienced physicians. Although disclosure is the ethical standard, the consequences of disclosure are feared by many. This article focuses on the issues that surround medical errors as they pertain to medical students and residents. It is important that this group of future physicians has appropriate training, mentoring, and support when dealing with errors.

Aged↗
PubMed2004

Relative effects of angiotensin converting enzyme inhibitors and calcium antagonists in advanced diabetic nephropathy.

OBJECTIVE: We have previously observed that calcium antagonists (CA) were associated with poorer renal survival in African Americans (AA) with diabetic nephropathy (DN). Here, we investigate further the effects of CA alone, or in combination with angiotensin converting enzyme inhibitors (ACEI) in advanced DN. DESIGN: Retrospective study. SETTING: Academic nephrology clinic. PATIENTS: 1) Patients who entered the endstage renal disease (ESRD) program in years 1993-1998 with a primary diagnosis of DN. 2) A cross-sectional analysis of pre-ESRD patients with DN, first seen in the clinic in 1996, then followed until 2000. Over 80% of patients were AA, and approximately 75% were female in both cohorts. INTERVENTIONS: Patients were categorized according to whether they were on either an ACEI or a CA, alone, or a combination of these, at presentation to the clinic, and during follow up. MAIN OUTCOME MEASURES: Renal survival (time to ESRD) and effects on blood pressure. RESULTS: In both data sets, patients presented with advanced renal disease. Those on CA tended to have lower blood pressure on presentation, and during follow up, and were more likely to experience a significant decrease in blood pressure over the course of follow up. Using a Cox proportional hazards model, ACEI-CA status was not found to be significantly associated with renal survival. CONCLUSIONS: Calcium antagonists (CA) are effective at lowering blood pressure in advanced DN, and do not appear to negatively affect renal survival, especially when combined with an ACEI.

Academic Medical Centers↗
PubMed2004

Therapeutic controversies in hypertension management: angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers in diabetic nephropathy? ACE inhibitors.

Diabetic nephropathy is the number one cause of endstage renal disease in the United States. Blood pressure is most important in delaying the progression of renal disease in persons with diabetes and, agents that block the renin angiotensin system (RAS) should be the primary agents used to achieve blood pressure reduction. There is debate regarding which method of RAS blockade should be used as primary therapy in persons with diabetes. There are not significant differences between angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) with regard to renal outcomes. Consideration of the enormously high rates of cardiovascular disease (CVD) in persons with diabetes and renal disease is the primary factor in choosing agents for blood pressure reduction. The ACE inhibitors and ARBs have been shown to reduce cardiovascular events in persons with diabetes and, there are recent comparable trials between the 2 classes. Some studies and meta-analyses show ACE inhibitors as being superior with regard to cardioprotection. In our nephrology clinic, we find that patients who presented on an ACE inhibitor had significantly lower CVD than those on ARBs (49.2% vs 70.1% prevalence of CVD, ACE inhibitor vs ARB respectively, P=.042). We conclude that ACE inhibitors should be strongly considered as the primary method of RAS inhibition in persons with diabetes.

Black or African American↗
PubMed2003

Hexosamines and TGF-beta1 use similar signaling pathways to mediate matrix protein synthesis in mesangial cells.

Hyperglycemia-induced alterations in mesangial (MES) cell function and extracellular matrix (ECM) protein accumulation are seen in diabetic glomerulopathy. Transforming growth factor-beta1 (TGF-beta1) mediates high-glucose-induced matrix production in the kidney. Recent studies demonstrated that some of the effects of high glucose on cellular metabolism are mediated by the hexosamine biosynthesis pathway (HBP) in which fructose-6-phosphate is converted to glucosamine (GlcN) 6-phosphate. We previously showed that the high-glucose-mediated fibronectin and laminin synthesis in MES cells is mediated by the HBP and that GlcN is more potent than glucose in inducing TGF-beta1 promoter luciferase activity. In this study, we investigated the hypothesis that the effects of glucose on MES matrix production occur via hexosamine regulation of TGF-beta1. Culturing simian virus (SV)-40-transformed rat kidney MES cells in 25 mM glucose (HG) for 48 h increases cellular fibronectin and laminin levels about twofold on Western blots compared with low glucose (5 mM). GlcN (1.5 mM) or TGF-beta1 (2.5-5 ng/ml) for 24-48 h also increases ECM synthesis. However, the effects of HG or GlcN with TGF-beta1 are not additive. The presence of anti-TGF-beta1 antibodies (20 microg/ml) blocks both TGF-beta1- and GlcN-induced fibronectin synthesis. TGF-beta1 increased ECM levels via PKA (laminin and fibronectin) and PKC (fibronectin) pathways. Similarly, TGF-beta1 and hexosamines led to nonadditive increases in phosphorylation of the cAMP responsive element binding transcription factor. These results suggest that the effects of excess glucose on MES ECM synthesis occur via HBP-mediated regulation of TGF-beta1.

Adenosine Triphosphate↗
PubMed2003

Are low target blood pressure goals justified in persons with diabetes mellitus?

Hypertension is common in patients with diabetes and is a major risk factor for development and progression of the macro- and microvascular complications seen in diabetes. The Joint National Committee VI recommendation for goal blood pressure is less than 130/85 mm Hg in diabetics--a more aggressive target than in nondiabetic patients. Data over the past decade support these aggressive goals, especially for cardiovascular and renal outcomes and overall mortality. In addition, in diabetics, blood pressure appears to be a continuous risk factor for these outcomes without evidence of a J-point effect. While these goals are rarely obtained in diabetic patients, studies demonstrate that they are achievable with attention to detail and use of multiple antihypertensive agents.

Antihypertensive Agents↗
PubMed2003

From 1960s Evans County Georgia to present-day Jackson, Mississippi: an exploration of the evolution of cardiovascular disease in African Americans.

Cardiovascular disease (CVD) is the No. 1 cause of mortality in the United States and it disproportionately affects African Americans. However, there are earlier reports that African Americans had significantly less CVD than whites. This racial discrepancy in CVD rates was noticed primarily for coronary heart disease (CHD). This issue was examined in the Evans County (Georgia) Cardiovascular Disease Study conducted in the 1960s. It showed that African American men had significantly lower rates of CHD than white men. Over the last couple of decades, the rates of CVD have been declining. However, the rate of decline of CVD in African Americans has not been equal to that seen in whites, such that African Americans now have a disproportionate share of CVD in the United States. In the 1990s, the Jackson Heart Study was designed to explore the reasons for the current racial discrepancy. This articles reviews the findings of the Evans County Study and explores various hypotheses for why CVD in African Americans has evolved from a disease from which African Americans may have been "protected" to one in which they shoulder a disproportionate burden.

Black or African American↗