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Biomedical subjects

J de Graeff

Publications and source records attributed to J de Graeff.

At least 19 recordsLinked to original sources

Observations on computerized quantitative bone scintigraphy in renal osteodystrophy.

Skeletal radiotracer (99mTc-HEDP) uptake was quantitated with and without the aid of a computer in 30 chronic dialysis patients with histologic evidence of renal osteodystrophy. Before scintigraphy, elevated soft-tissue activity due to the absence of renal radiotracer excretion was reduced by hemodialysis. The results were compared with those of a normal group and with the results of the biochemical and the bone morphometric studies of these patients. In all patients the radiotracer uptake was elevated, often markedly. In several patients with minimal histologic bone disease, however, soft-tissue activity could not be normalized by hemodialysis although its influence on the quantitative data could be further reduced (but not excluded) by computer evaluation of skeletal radiotracer uptake. Since the latter technique clearly distinguished the majority of the patients from the normals, it appears that computerized quantitative skeletal analysis is a potentially accurate scintigraphic method for detecting renal osteodystrophy. The significant relationship between skeletal radiotracer uptake, in particular at the bone biopsy site, and only the histologic features of increased bone turnover suggest that hyperparathyroidism is the major cause of this increased tracer uptake in renal osteodystrophy.

Adolescent↗

Beneficial effect of HLA-A and B matched pretransplant blood transfusions on primary cadaveric kidney graft survival.

The effects of HLA-A and B matched pretransplant blood transfusions on the survival of a primary cadaveric kidney graft were studied prospectively in a group of 15 patients who had never received a transfusion and had never been pregnant. Kidney graft survival at one year was 87%, whereas a group of 14 nontransfused patients who underwent transplantation in the same center (before this study was initiated) had a graft survival of only 7%. Twenty-six patients who received a transplant in the same center just before and after each protocol patient served as controls. There were no prior pregnancies in this group; all patients had received blood transfusions from random blood bank donors. Kidney graft survival at one year was 76% for this control group, which is not statistically different from that found for the protocol group. Graft survival for the 13 contralateral kidneys from the protocol group donors was only 50% at one year. These kidneys, however, were transplanted in various other centers. From our study, prolongation of kidney graft survival could be demonstrated for patients receiving pretransplant HLA-A-and-B-matched blood transfusions. Sera screening indicated that lymphocytotoxicity might be reduced by pretransplant HLA-A-and-B-matched blood transfusions. The presence of pretransplant antibodies with specificities for HLA-A and/or B could be significantly correlated with poor graft survival.

Adolescent↗

Effect of warm ischemia time and HLA (A and B) matching on renal cadaveric graft survival and rejection episodes.

In a retrospective single-center study the influence of warm ischemia time and simultaneous influence of HLA (A and B) matching on one-year renal graft survival was analyzed in 170 adult recipients of primary cadaveric renal grafts. One-year survival of grafts with warm ischemia times longer than 50 min was only 40% (n = 10). When warm ischemia time was shorter than 50 min, a 1-min increase of warm ischemia time correlated with 1% decrease in one-year graft survival as a result of rejection. This detrimental effect of warm ischemia time on graft survival was not yet significant one month after transplantation, but became more evident as follow-up time was lengthened. Warm ischemia time also correlated with the number of reversible rejection episodes in patients with a graft functioning for longer than one year (P less than 0.04). The beneficial influence of HLA (A and B) matching on one-year graft survival was significant (P less than 0.05 log linear test). This influence was even more evident with longer warm ischemia times. It is concluded that warm ischemia has a detrimental influence on graft survival that is mediated by rejection, and it is suggested that this might be due in part to altered presentation or expression of HLA-antigens of ischemically damaged kidney tissues.

Adult↗

Transplant survival and clinical course after pretransplant HLA-A and B matched blood transfusions: a single centre study.

The effects of HLA-A and B matched pretransplant blood transfusions on the outcome of primary cadaveric kidney transplantation were studied prospectively in a group of 15 patients who had never received a transplant and had never been pregnant. From our study, prolongation of graft survival could be demonstrated for patients receiving pretransplant HLA-A and B matched blood transfusions. The clinical course was comparable to that found in a group of patients who received random pretransplant blood transfusions, although there were considerably more patients in this latter group hospitalised for a very long period, a fact which could be attributed mainly to viral infections.

Adolescent↗

Increased bone radiotracer uptake in renal osteodystrophy. Clinical evidence of hyperparathyroidism as the major cause.

Bone radiotracer uptake in renal osteodystrophy was investigated in 35 dialysis patients by correlating the results of quantitative bone scintigraphy with those of biochemical and bone morphometric studies. There were highly significant correlations (P less than 0.001) between the total skeletal activity and the biochemical (iPTH and alkaline phosphatase), and histologic parameters of hyperparathyroidism. These clinical results strongly suggest that increased bone turnover i.e. hyperparathyroidism, rather than osteomalacia is the major cause of increased skeletal uptake in renal osteodystrophy.

Adolescent↗

Genetic counselling for adult polycystic kidney disease. Ultrasound a useful tool in pre-symptomatic diagnosis?

A study was performed to assess the reliability and sensitivity of ultrasound for the screening of asymptomatic children of patients with known adult polycystic kidney disease (APKD) and to compare this technique with the IVP and conventional laboratory techniques. Ultrasound appears to be at least as sensitive as IVP for identifying carriers of the gene for polycystic kidney disease. The identification of about 50% of a group of 21 asymptomatic individuals-at-risk in the 21-30-year age group as gene carriers, both with ultrasound and IVP, is promising for the early detection of this disease and therefore for genetic counselling in the future. This is the first step toward the construction of an age-specific detection curve for gene carriers, which is necessary in order to be able to calculate the probability that symptomatic subjects-at-risk carry the APKD gene.

Adult↗

Less aggressive rejection therapy and low-dose corticosteroids leading to satisfactory cadaveric kidney graft survival and low morbidity rate.

A less aggressive approach in treatment of rejection crises has been introduced since January 1979. Findings in 39 patients demonstrate that rejection treatment can be started later and be applied with considerably less frequency without an increase in graft loss. A reduction of more than 50% in corticosteroid dosage applied within three months after transplantation seems to be possible, with a sharp decrease of morbidity rate.

Cadaver↗

Metastatic skin calcification. A rare phenomenon in dialysis patients.

Calcification of the skin could not be demonstrated in 60 skin biopsy specimens, selectively obtained from 30 chronic hemodialysis patients; 21 of these patients had metastatic calcification at other sites. These results support the proposed rarity of metastatic skin calcification in patients with chronic renal failure. The cause of this phenomenon is not precisely known.

Adolescent↗

Antibodies directed against antigens on the endothelium of peritubular capillaries in patients with rejecting renal allografts.

This study was undertaken to examine the humoral immune response against endothelial antigens of the donor kidney in human renal allograft recipients. Sera from 61 transplant recipients who received 62 grafts were studied for the presence of circulating endothelial antibodies (CEAb) using an indirect immunofluorescence technique with a pretransplant biopsy of the graft as a substrate. IgG antibodies directed against the endothelium of peritubular capillaries were found in the sera of 6 of the 10 patients with graft rejection within 7 weeks after transplantation, whereas these antibodies were not found in the absence of rejection (P less than 0.001). Immunofluorescence studies of post-transplant biopsies showed IgG along the endothelium of peritubular capillaries only in the grafts of patients with CEAb. Eluates from these grafts contained IgG antibodies that bound to the endothelium of the donor as shown by the indirect immunofluorescence technique. Absorption of endothelial antibody (EAb)-positive sera with human platelets or Wistar strain rat erythrocytes showed that the EAb were not directed against serologically defined HLA antigens or against heterophile antigens on rat erythrocytes. We conclude from this study that the presence of antibodies directed against endothelial antigens is associated with poor graft prognosis and that these antibodies may be responsible for the rejection process.

Animals↗

Cadaveric graft survival, clinical course, blood transfusion, HLA (A and B) match, and DR match in adult patients transplanted in one centre.

The influence of blood transfusions, HLA, A and B, DR matching was studied in adult patients transplanted in one centre. The conclusions were: 1. Pre-transplant blood transfusion(s) are a prerequisite for graft acceptance. 2. In transfused patients with no HLA A and B mismatch, there is only 8% graft loss due to irreversible rejection. 3. In transfused patients with a functioning graft after six months, a decrease in the number of reversible rejection crises is observed in patients with no HLA A and B mismatch or with identity for HLA B7 or HLA B8. 4. Identity for HLA B7 or B8 also gives a higher chance of a late onset of the first rejection crisis.

Antibody Specificity↗

Scintigraphic detection of gastric calcification in dialysis patients.

The value of 99mTc HEDP bone scintigraphy as a means of detecting metastatic gastric calcification was studied in 45 chronic dialysis patients and in 55 former dialysis patients. For this group, all bone scans were obtained within 2 months after successful transplantation; radiotracer uptake by the stomach was not observed. In 15 of the first 35 chronic dialysis patients studied, gastric uptake was demonstrated without radioactive accumulation in the thyroid region. In all the dialysis patients, however, background activity had been normalized before scintigraphy by means of hemodialysis using recirculating dialysate. Without the latter, radioactive accumulation in the stomach was no longer noted. Thus, gastric uptake was presumably due to the formation of in vivo free pertechnetate, as a result of the dialysis method used, and in vitro experiments supported this hypothesis. These findings show that free pertechnetate can cause visualization of the stomach in the absence of thyroid imaging. The results of this study further indicate that bone scintigraphy is not a sensitive method for detecting metastatic gastric calcification in uremia.

Adolescent↗