PubMed Health⌕ Search

Biomedical subjects

Vincent M Brandenburg

Publications and source records attributed to Vincent M Brandenburg.

At least 19 recordsLinked to original sources
PubMed2006

Fetuin-A and kidney function in persons with coronary artery disease--data from the Heart and Soul Study.

BACKGROUND: Fetuin-A is a serum protein that inhibits ectopic vascular calcification and is present in lower concentrations in end-stage renal disease than in healthy controls. Whether fetuin-A concentrations are also lower in the setting of mild-to-moderate chronic kidney disease (CKD) is unknown. METHODS: We evaluated the associations of several parameters of kidney function including measured 24 h urinary creatinine clearance (CrCl), estimated glomerular filtration rate (GFR) by the Mayo Clinic quadratic GFR equation (qGFR), serum cystatin-C concentrations, and urinary albumin-to-creatinine ratio with serum fetuin-A concentrations in 970 outpatients with coronary artery disease. We used general linear models to determine the adjusted mean fetuin-A concentrations within each kidney function category. RESULTS: The mean age of the study sample was 67 years, 82% were male, 71% had hypertension and 26% had diabetes mellitus. In adjusted analysis, we observed no significant differences in mean fetuin-A concentrations across groups defined by CrCl, qGFR, or albumin-to-creatinine ratio groups. For example, adjusted mean fetuin-A concentrations were 0.66 g/l in participants with CrCl > 90, 60-90 and 45-60 ml/min/1.73 m(2), and 0.65 g/l in participants with CrCl < 45 ml/min/1.73 m(2). Higher serum cystatin-C (indicating worse kidney function) was associated with higher adjusted mean serum fetuin-A concentrations (lowest quartile 0.62 g/l, highest quartile 0.68 g/l; P for trend <0.001). CONCLUSIONS: Among ambulatory patients with coronary artery disease, there is no evidence that mild-to-moderate CKD is associated with lower concentrations of serum fetuin-A compared with persons with normal renal function. The mechanisms explaining the association between CKD and vascular calcification remain elusive.

Aged↗
PubMed2006

Association between human fetuin-A and the metabolic syndrome: data from the Heart and Soul Study.

BACKGROUND: Fetuin-A is a multifunctional hepatic secretory protein that inhibits the action of insulin in experimental animals. We evaluated the association between human serum fetuin-A and the metabolic syndrome (MetS) in a cohort of persons with coronary artery disease. METHODS AND RESULTS: We defined MetS by the National Cholesterol Education Program criteria among 711 nondiabetic outpatients with coronary artery disease. The mean age was 67 years, and 82% were male. We divided participants into quartiles by serum fetuin-A concentrations. A total of 45% of participants (80 of 177) in the highest quartile of fetuin-A had MetS compared with 24% of participants (42 of 177) in the lowest quartile (odds ratio, 2.7; 95% confidence interval, 1.7 to 4.2; P<0.001). This association persisted after adjustment for potential confounding variables, including hypertension, body mass index, and inflammatory biomarkers (adjusted odds ratio, 2.0; 95% confidence interval, 1.1 to 3.5; P=0.02). Higher fetuin-A quartiles were also strongly and independently associated with higher low-density lipoprotein, non-high-density lipoprotein (HDL), and triglyceride concentrations and lower HDL concentrations (all P<0.01). CONCLUSIONS: Higher human fetuin-A concentrations are strongly associated with MetS and an atherogenic lipid profile. Future studies should evaluate whether fetuin-A predicts coronary artery disease risk.

Aged↗
PubMed2005

Lumbar bone mineral density in very long-term renal transplant recipients: impact of circulating sex hormones.

The influence of circulating sex hormones and gender on the bone mineral density (BMD) in long-term renal transplant recipients needs further investigation. We performed a retrospective analysis of lumbar BMD between 6 years and 20 years after renal transplantation. In 67 patients (47+/-12 years, 38 male) with a minimum interval of 72 months after transplantation, lumbar BMD measurements (dual energy X-ray absorptiometry) were performed (=complete cohort). Thirty-one patients (=longitudinal cohort) underwent at least three serial BMD measurements (mean follow-up 39+/-18 months, start at 86+/-22 months). All patients received prednisolone. In the complete cohort, BMD was significantly reduced in comparison to young healthy (mean T-score -1.33+/-1.40) and age-matched controls (mean Z-score -0.91+/-1.45) at 88+/-31 months (p<0.05). Osteopenia or osteoporosis were present in two-thirds of patients. In the longitudinal cohort, a mean annual lumbar BMD loss of -0.6+/-1.9% was detectable equivalent to a -0.03+/-0.15 reduction of Z-scores per year (regression analysis). Impact of hormonal status: In the complete cohort, postmenopausal status was associated with significantly lower BMD levels compared to men (p=0.0441). Women and men within the lowest tertile of sex hormone levels (LH, FSH, DHEAS, testosterone, progesterone, estradiol) did not exhibit significant differences in terms of lumbar BMD compared to those in the highest tertile. The mean annual bone loss was statistically indistinguishable between men and women. There was no significant correlation of sex hormone levels and BMD in men and premenopausal women. In postmenopausal women, however, low estradiol and high LH levels correlated with the extent of annual BMD loss (p<0.05). Our data confirm significantly reduced lumbar T-scores in the very late period after renal transplantation. The lumbar BMD decreased by -0.6+/-1.9% per year. In postmenopausal long-term renal transplant recipients, low estradiol levels were associated with accelerated bone loss.

Adult↗
PubMed2004

Early rapid loss followed by long-term consolidation characterizes the development of lumbar bone mineral density after kidney transplantation.

BACKGROUND: Bone mineral density (BMD) decreases significantly early after renal transplantation. This prospective study was designed to evaluate the long-term lumbar BMD development. METHODS: Sixty-three renal-transplant recipients (mean age 44 +/- 12 years, 37 [59%] male) underwent serial yearly posttransplant laboratory parameter and BMD measurements of the lumbar spine (dual energy x-ray absorptiometry). Combined maintenance immunosuppression included prednisolone in 95% of patients. The minimum number of consecutive scans was three; the maximum number seven (n = 15). Examinations were performed between 3 +/- 2 and 68 +/- 4 months posttransplant. RESULTS: BMD was significantly lower compared with healthy controls at all times after transplantation. t scores were below -1. BMD development revealed a biphasic pattern: between 3 +/- 2 and 10 +/- 2 months, a significant BMD decrease of -0.016 +/- 0.055 g/cm2 (-1.6%, P = 0.024) occurred. Later, a moderate increase resulting in BMD stability until the sixth year posttransplant was detected. Within the first year, posttransplant osteocalcin (from 19 +/- 15 to 32 +/- 23 microg/L) and calcitriol (from 24 +/- 15 to 43 +/- 24 ng/L) displayed a significant increase. Compared with patients with a pronounced decrease, patients with a substantial increase in early posttransplant BMD had a lower baseline BMD (0.989 +/- 0.131 vs. 1.149 +/- 0.202 g/cm2 [P = 0.0122]) and lower creatinine levels (105 +/- 23 vs. 141 +/- 53 mmol/L [P = 0.0227]). CONCLUSION: Our study confirms a significant decrease of lumbar BMD early after renal transplantation. Bone loss was less pronounced than previously described. The longitudinal follow-up verifies a previously assumed biphasic lumbar BMD development: after the first year, no further significant bone loss occurred, and bone density remained relatively stable at significantly lower levels compared with healthy controls.

Absorptiometry, Photon↗
PubMed2004

Factor Xa-activated whole blood clotting time (Xa-ACT) for bedside monitoring of dalteparin anticoagulation during haemodialysis.

BACKGROUND: Low molecular weight heparins (LMWH) like dalteparin are increasingly used for anticoagulation during haemodialysis (HD). The available laboratory tests for monitoring LMWH anticoagulation are time-consuming and expensive, and the suitability of the conventional activated clotting time (ACT) is controversial. A simple and cheap bedside test would be useful. METHODS: We studied the factor Xa-activated whole blood clotting time (Xa-ACT) in vitro and in vivo in nine patients undergoing chronic HD with i.v. dalteparin bolus anticoagulation and compared it with the conventional ACT. Plasma anti-factor Xa (antiXa) activity was determined with a chromogenic assay. Thrombin-antithrombin complexes were measured to detect coagulation activation. RESULTS: Xa-ACT and ACT were prolonged with rising dalteparin concentration. In vitro, both clotting times were strongly correlated with the antiXa levels (r = 0.94 and 0.89, respectively). Nevertheless, compared with the ACT, the Xa-ACT was considerably more sensitive to the LMWH in vitro (healthy blood: Xa-ACT 90 s/U vs ACT 26 s/U; uraemic blood: Xa-ACT 96 s/U vs ACT 31 s/U) as well as in vivo (Xa-ACT 81 s/U vs ACT 22 s/U) and reflected different intensities of anticoagulation. An initial dalteparin bolus of 80+/-11 U/kg body weight was able to prevent coagulation activation for up to 4 h of HD. CONCLUSION: For monitoring LMWH anticoagulation the Xa-ACT was superior to the conventional ACT in vitro as well as in vivo during HD. The Xa-ACT can be useful as a LMWH bedside test. The ACT was not sensitive enough to serve as a LMWH monitoring tool.

Adult↗
PubMed2004

HELLP syndrome, multifactorial thrombophilia and postpartum myocardial infarction.

A case of postpartum acute myocardial infarction with intraventricular thrombus occurred in a woman with HELLP syndrome. Since coronary artery disease was ruled out angiographically, the assumed pathophysiological mechanism for myocardial malperfusion was intermittend coronary vasospasm and thrombosis. There were several thrombophilic risk factors detectable (heterozygous factor V Leiden, low levels of antithrombin III, protein S deficiency), whose possible impact in this rare but severe clinical condition is discussed.

Adult↗
PubMed2003

Hemolysis, hemorrhage, headache, and hidden abortion: imaging findings in antiphospholipid syndrome.

Antiphospholipid antibodies are associated with arterial and venous thromboses, recurrent pregnancy loss, and organ infarction. Any vascular region can be affected. We present a 20-year-old woman suffering from secondary antiphospholipid syndrome with a unique combination of multifocal venous thromboses, pulmonary embolism, spontaneous abortion, and splenic infarction. Diversity of clinical symptoms and diagnostic imaging modalities are discussed with emphasis on cross-sectional imaging. The syndrome should be suspected in patients with thromboses and organ infarctions of otherwise undetermined etiology.

Abortion, Spontaneous↗
PubMed2002

[Pulmonary alveolar microlithiasis--a rare cause of bilateral extensive pulmonary infiltrates].

BACKGROUND: Pulmonary alveolar microlithiasis is a rare disease, which is characterized by pulmonary deposition of calcium phosphate microliths. The radiographic features can be pathognomonic with a "sandstorm"-like opacification throughout the lungs. CASE REPORT: A 29-year-old Moroccan presented for the first time 1988 with atypical chest pain. His history was characterized by nephrocalcinosis and pulmonary disease. Physical examination and laboratory values were unremarkable. Chest X-ray revealed extensive bilateral pulmonary infiltrates with "sandstorm"-like opacifications. Sonography showed medullary nephrocalcinosis. The diagnosis of pulmonary alveolar microlithiasis was confirmed by transbronchial biopsy. Over the next 13 years there was only a moderate expansion of the pulmonary infiltrates and a beginning restrictive pattern, whereas the patient was almost symptom-free. CONCLUSION: Pulmonary alveolar microlithiasis is a rare cause of bilateral pulmonary infiltrates and should be considered in the differential diagnosis. In some cases there is also an association with calcifications of extrapulmonary organs.

Adult↗