Biomedical subjects

Henk Boom

Publications and source records attributed to Henk Boom.

3 recordsLinked to original sources

PubMed2005

The absence of delayed graft function is predicted by the presence of manganese-superoxide dismutase in distal tubules of renal allografts.

BACKGROUND: Acute tubular necrosis (ATN) in renal allograft biopsies correlates poorly with delayed graft function (DGF). Factors involved in the pathogenesis of DGF were evaluated in biopsies in an attempt to refine the recognition of DGF. METHODS: Anti-cubulin and anti-AE-1/AE-3 antibodies identified proximal and distal tubules, respectively. The terminal deoxynucleotide transferase-mediated dUTP nick-end labeling technique and active caspase-3 staining were used to demonstrate apoptosis. Antibodies against superoxide dismutase (SOD) were used as markers of the protective tubular response. Tubular regeneration was evaluated using anti-ki 67 and antivimentin antibodies. RESULTS: Of a total of 40 biopsies, 9 were associated with DGF. ATN was seen in 16 biopsies; 5 were associated with DGF. The finding of ATN in the biopsy of a graft predicted DGF in only 56% of cases. Absence of distal caspase-3 staining predicted the absence of ATN in 87% of cases. The presence of caspase-3 predicted ATN in 54% of cases. The detection of manganese-SOD in distal tubules predicts the absence of DGF in 76% of the cases. CONCLUSIONS: The use of immunohistochemical staining on posttransplant renal biopsies improved its predictive value with respect to ATN and DGF: The absence of active caspase-3 in distal tubular epithelium predicts the absence of ATN in 87% of cases, whereas its presence predicts ATN in 54% of cases. The presence of manganese-SOD in distal tubules predicts the absence of DGF in 76% of cases.

Biopsy↗

PubMed2004

Calcium levels as a risk factor for delayed graft function.

BACKGROUND: Delayed graft function (DGF) occurs in up to 50% of renal transplants. Hypercalcemia and hyperparathyroidism are associated with impaired renal function. Little is known on the effects of serum calcium levels on DGF. This issue was addressed in the current study. METHODS: Patients receiving a cadaveric renal transplant between 1986 and 1996 were studied. Data on calcium metabolism and histologic characteristics of nephrocalcinosis, acute tubular necrosis (ATN), and acute rejection in biopsies taken within the first week were related to the occurrence of DGF. RESULTS: The incidence of DGF in a cohort of 585 cadaveric transplants was 31%. DGF correlated independently with serum calcium levels (odds ratio [OR] 1.14 [95% confidence interval (CI) 1.04-1.26] per 0.1 mmol/L). The use of calcium channel blockers before transplantation protected against DGF (OR 0.5 [95% CI 0.29- 0.87]). In this selected group, we found an association with histologic signs of ATN and DGF. However, most of the biopsies also had features of acute rejection or nephrocalcinosis. Nephrocalcinosis was found in 12 of 71 biopsies and was not associated with serum calcium levels or the occurrence of DGF. CONCLUSIONS: In this study, serum calcium levels were independently associated with DGF. This could not be explained by the presence of microscopic nephrocalcinosis. Therefore, DGF is attributed to high intracellular calcium levels. Because calcium supplementation and vitamin D analogues are commonly used in dialysis practice, hypercalcemia influences long-term graft outcome by its effect on DGF. The pretransplant use of calcium channel blockers has a protective effect on the occurrence of DGF.

Adult↗

PubMed2002

Delayed graft function is characterized by reduced functional mass measured by (99m)Technetium-mercaptoacetyltriglycine renography.

BACKGROUND: The mechanism that underlies delayed graft function (DGF) is still poorly defined. Previous studies using tubular function tests have shown that postischemic injury to the renal transplants results in profound impairment of paraimmunohippurate (PAH) extraction through the tubules. METHODS: Using (99m)Technetium-mercaptoacetyltriglycine ((99m)Tc-MAG3) renography and tubular function slope (TFS), a study of the tubular uptake of (99m)Tc-MAG3 was undertaken in a prospective study of renal transplant recipients with immediate graft function (IGF) and those with DGF. RESULTS: A total of 37 consecutive recipients of a cadaveric graft and 5 kidneys from living donors was evaluated within 48 hours after transplantation and in week 2, months 3 and 6, and 3 years after transplantation. In addition to the protocol scans, recipients with DGF were examined every other day until function was resumed. Repeated measurement two-way analysis of variance and a change point analysis were performed to determine the difference in the follow-up of TFS values between the two groups. Fourteen patients were classified as having DGF and 28 immediate graft function. In the DGF group, the initial TFS value was significantly lower than in the immediate graft function group (0.54 [+/-0.01] and 1.75 [+/-0.16], respectively; P=0.002), a difference that persisted for up to 3 years. Change point analysis revealed that the postischemic tubular excretion improved with time in both groups in the first 3 to 4 weeks, but both groups remained different up to 3 years after transplantation. Multivariate analysis revealed that only the cold ischemic time was an independent risk factor for a low TFS value. After the initial recovery from postischemic injury, the TFS may be used as a marker for functional renal mass. CONCLUSION: We propose that the tubular defect in DGF, as defined by (99m)Tc-MAG3 renography, is irreversible and may be a marker of initial graft function.

Adult↗