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Biomedical subjects

C Holmberg

Publications and source records attributed to C Holmberg.

At least 55 records · Page 3Linked to original sources

Kidney function after 1:1 conversion to the cyclosporine microemulsion formulation in children with liver allografts.

BACKGROUND: One-to-one (mg:mg) conversion from the conventional to the microemulsion formulation of cyclosporine (CsA) is advocated as a simple way to use the new therapeutic regimen. However, the potentially harmful effects of the conversion on kidney function in nonrenal transplant recipients are poorly known. METHODS: Renal effects of the conversion were prospectively investigated in 22 pediatric liver transplant recipients (mean age, 8.4 years; mean time from transplantation, 3.2 years). Patients were followed for 12 months. Pharmacokinetic studies were performed at baseline and 5 days and 6 and 12 months after conversion. RESULTS: Peak concentration, minimum concentration, average steady state concentration, and area under the concentration-versus-time curve increased by 60-130% after conversion. Graft losses, progressive deterioration of graft function, and acute rejection episodes did not occur. The mean glomerular filtration rate (GFR) was 103 ml/min/1.73 m2 at baseline and 100 ml/min/1.73 m2 after 12 months. However, 6 of the 22 patients showed at least a 15% (range, 16-38%) decrease in GFR between baseline and 6 months (P<0.01). They had a significantly higher increase in average steady state concentration between baseline and 6 months than the six patients with the best outcome in GFR during the same time period (164 ng/ml vs. 53 ng/ml, P<0.05). At this point (6 months), target CsA trough levels were reduced by 20-30%, while the mean area under the concentration-versus-time curve remained above that obtained at baseline. The GFR of three of the six patients subsequently improved. CONCLUSIONS: One-to-one conversion can be performed safely in liver transplant recipients if strict follow-up is feasible.

Adolescent↗

Apoptotic cell death in human chronic renal allograft rejection.

Chronic renal allograft rejection is characterized by gradual progression suggesting persistent low-grade injury. Apoptotic cell death may be initiated by low-grade injury secondary to external factors, making apoptosis a potential pathway of chronic rejection. In the present investigation, protocol kidney biopsies of 20 pediatric renal allograft recipients (12 with chronic rejection and 8 with normal histology), 9 pediatric liver allograft recipients, and 7 children with minimal change nephrotic syndrome were evaluated. The presence of apoptotic cell death was studied by determining apoptosis-induced oligonucleosomal DNA fragmentation in the biopsy specimens using 3' end labeling with terminal transferase, gel fractionation, and Southern blotting. The specific cell types with increased DNA fragmentation were determined by in situ 3' end labeling performed on sections of the biopsies. Significant DNA fragmentation was found only in the specimens from patients with chronic rejection. In situ investigation revealed increased apoptosis of both proximal and distal tubular epithelial cells, but not in the glomeruli or interstitium. The mean number of apoptotic tubular epithelial cells per 400x magnified field was higher in the renal allografts than in kidneys of liver transplant recipients or patients with minimal change nephrotic syndrome (2.3 vs. 0.8, P<0.05, in both cases). Our data provide biochemical evidence of increased apoptotic cell death of renal tubular epithelial cells in patients undergoing chronic renal allograft rejection.

Adolescent↗

Infections in infants with congenital nephrosis of the Finnish type.

The incidence and type of infections were retrospectively analyzed in 21 infants with congenital nephrosis of the Finnish type (CNF). During the median follow-up time of 1.1 years the infants suffered from 63 verified and 62 suspected episodes of sepsis. These accounted for half of all infections recorded. Forty percent of bacteremias were caused by coagulase-negative staphylococci, 16% were caused by Staphylococcus aureus, 17% were streptococcal, and 24% were caused by Gram-negative bacteria. One infant died of pleural empyema, but otherwise the outcome of infections was good. The use of central venous lines tended to increase the rate of staphylococcal bacteremias but had no significant effect on the overall incidence of infections. Prophylactic use of antibiotics did not reduce the incidence of septic or other infections. Infants with CNF had low levels of serum IgG, but prophylactic immunoglobulin infusions (0.5-1.0 g once or twice a week) did not reduce the frequency of infections, probably because the infused IgG was quickly lost into the urine. The results indicate that infants with CNF often suffer from septic infections associated with the invasive treatment modalities. Parenteral antibiotics covering the hospital strains of bacteria (especially staphylococci) should be started without delay when a nephrotic patient is not doing well.

Anti-Bacterial Agents↗

Circulating luteinizing hormone receptor inhibitor(s) in boys with chronic renal failure.

Patients with chronic renal failure frequently have hypogonadism. To elucidate the molecular mechanisms involved, we tested the ability of serum from these patients to inhibit recombinant human luteinizing hormone receptors. Using a cell line expressing functional human luteinizing hormone receptors, we found that adenosine 3'5'-monophosphate (cAMP) production was markedly inhibited by sera from the patients, but not by sera from healthy subjects. Inhibition of cAMP production was associated with inhibition of 125I-human chorionic gonadotropin binding. Inhibition of LH receptors by sera from patients correlated with the glomerular filtration rate and after renal allograft transplantation, decreased. Fractionation of serum samples indicated the receptor-inhibiting activity in proteins of molecular weights from 30,000 to 60,000 Daltons. When characterized and purified, the factor responsible may well be a new LH receptor antagonist of clinical significance.

Blood Proteins↗

Improved prenatal diagnosis of the congenital nephrotic syndrome of the Finnish type based on DNA analysis.

Haplotype analysis and alpha-fetoprotein quantitation comprise a prenatal diagnosis of congenital nephrosis. Congenital nephrotic syndrome of the Finnish type (CNF) is an autosomal recessive disease characterized by massive proteinuria and nephrotic syndrome from birth. Prenatal diagnosis of CNF has previously been based on the quantitation of alpha-fetoprotein (AFP) in the amniotic fluid and maternal serum, but an increased AFP is not specific for the disease. We have recently localized the CNF gene to the chromosome 19q13.1 region and observed a strong linkage disequilibrium to the genetic markers D19S610, D19S608, D19S224 and D19S220 in this chromosomal area. Four main CNF-haplotypes have been observed in Finnish kindreds. In the present study, linkage and haplotype analyses have been applied to prenatal diagnosis of six families with a history of CNF. The results diminish the risk of false positive diagnosis and abortions of healthy fetuses in families at risk.

Amniotic Fluid↗

Methylprednisolone exposure, rather than dose, predicts adrenal suppression and growth inhibition in children with liver and renal transplants.

Some patients receiving glucocorticoids develop adverse effects even with very low doses, whereas others fail to achieve the desired effects with the usual therapeutic doses. We hypothesized that glucocorticoid exposure, rather than the dose, would predict the development of adverse effects in children receiving long-term glucocorticoid treatment. Sixteen liver and 10 renal transplant recipients on triple immunosuppression were studied. Serum total methylprednisolone (MP) and cortisol were determined before and up to 10 h after peroral MP administration. Heights were recorded 6 months before and after the study day. The MP dose (in milligrams per kilogram) was not correlated with the serum cortisol concentration or with the change in height SD score. The area under the serum MP time vs. concentration curve was inversely related to the serum cortisol concentration and to the height SD score, and was the best predictor of both adrenal function and growth. Dosing according to area under the serum MP time vs. concentration curve in children receiving long-term glucocorticoid treatment may substantially reduce the incidence of adverse effects without affecting therapeutic efficacy.

Adolescent↗

Health-related quality of life after organ transplantation in childhood.

While sophisticated data on patient and graft survival are available, very little is known about the overall health-related quality of life (HRQOL) after organ transplantation (Tx) in childhood. We examined the perceived HRQOL of survivors of heart, liver and kidney Tx. A previously validated, age-appropriate, multidimensional questionnaire was completed by 59 survivors, currently aged 8-23 years, who had received an organ transplant in 1983-1994, at least 6 months prior to the study. The overall HRQOL score of the patients aged 8-11 was lower than that of the normal controls, while the HRQOL scores of the patients aged 12-15 and 16-23 were similar to those of the controls. However, the younger patients had more complex diseases. Compared to the controls, the patients reported more problems regarding their mobility, usual activities, and school and hobbies. In addition, the patients aged 8-11 reported more problems with eating, elimination, friends and ability to concentrate than the controls. There was an association between age at Tx and HRQOL, but no association between the type of Tx or time since Tx and HRQOL. The perceived emotional status of the patients was better than that of the controls, especially during and after adolescence. We conclude that to provide optimal care, patients HRQOL should be assessed. Although the survivors report problems, the overall HRQOL after Tx is good. The occurrence of complications before Tx appears to be a crucial factor as regards the long-term HRQOL of the survivors. Attention should be paid to treatment prior to Tx and to the timing of Tx in order to improve the HRQOL after Tx.

Adolescent↗

Kidney function in cyclosporine-treated pediatric heart transplant recipients.

BACKGROUND: End-stage kidney disease may develop in 1% to 3% of cyclosporine-treated heart transplant recipients, and most patients show a decreased glomerular filtration rate. There are little data on kidney function in pediatric recipients, although good function is needed for their optimal development. METHODS: Kidney function was prospectively investigated in 10 children receiving triple immunosuppression (cyclosporine, azathioprine, methylprednisolone) during the first 18 months after heart transplantation. The early cyclosporine trough level target was 300 to 500 micrograms/L and 100 to 200 micrograms/L after the first year. 51Chromium-ethylenediamine tetraacetic acid, para-amino hippuric acid, lithium, and sodium clearances, measurements of serum and urinary electrolytes, and urinary concentration tests were performed. Renal biopsy specimens were obtained from four patients after 18 months. RESULTS: Heart function was good in all patients. Six patients (60%) remained rejection-free at 18 months. The mean glomerular filtration rate was 92.4 ml/min/1.73 m2 before transplantation, increased to 115 by 6 months (p < 0.05), and thereafter remained stable. The mean renal plasma flow was 487 ml/min/1.73 m2 after 18 months. Hypertension was seen in all patients at discharge but in only one at 18 months. Mild hyperuricemia was the most common sign of tubular dysfunction occurring in five patients at discharge but in only two patients at 18 months. The result of kidney histopathologic study was normal in three of four patients, and cyclosporine nephrotoxicity was not diagnosed. CONCLUSIONS: Triple immunosuppression with cyclosporine adequately protects the graft against acute rejection. It is compatible with normal glomerular function and leads to only minor tubular disturbances.

Adolescent↗

Comparison of conventional oral cyclosporine and cyclosporine microemulsion formulations in children with a liver transplant.

We studied 22 children (mean age: 8.42 years, range: 1.9-15.6 years) with a liver transplant to compare the pharmacokinetics of oral cyclosporine (CsA) microemulsion to the conventional formulation. The CsA treatment (mean dose: 5.9 mg/kg/day, range: 3.0-11.7 mg/kg/day) was converted 1:1 on a milligram-to-milligram basis to the microemulsion formulation. Five days after the conversion, the mean peak blood CsA concentration was higher (microemulsion: 963 ng/ml, range: 518-1864 ng/ml; conventional: 431 ng/ml, range: 98-888 ng/ml; P<0.0001) and it was reached faster (median time of peak concentration: 1.6 hr vs. 2.9 hr, range: 1.0-3.0 hr vs. 1.9-4.0 hr; P=0.0009). The absorption lasted on the average 19% longer after the conventional formulation. The area under the concentration versus time curve (AUC) was larger after the microemulsion formulation in all but one patient (P=0.001) by a mean factor of 1.80 (range: 0.72-3.04). The trough CsA level after the microemulsion formulation was more closely related to peak concentration (r2=0.86 vs. 0.45) and AUC (r2=0.84 vs. 0.47); thus, therapeutic drug monitoring may be more useful. After 6 months on the new formulation, the results for the whole group were similar, but in five children the AUC was comparable to the AUC obtained with the conventional formulation. No rejections occurred, and the liver and kidney functions remained unchanged. A 1:1 conversion can be safely performed in children, based on a 6-month follow-up. However, the total drug exposure changes in significant ways, which, on a long-term basis, may improve the immunosuppression in an underimmunosuppressed patient, but may increase the risk for dose-related adverse effects in others.

Administration, Oral↗

Recombinant human growth hormone treatment. Its effect on renal allograft function and histology.

Our objective was to investigate the effects of recombinant human growth hormone (rhGH) treatment on long-term renal allograft function and histopathology. RhGH is a potent therapy for poor growth after renal transplantation. However, rhGH has proinflammatory properties and may induce acute rejection or accelerate chronic rejection. Nine prepubertal rhGH-treated renal transplanted children and nine pair-matched controls were studied 18 (before the start of rhGH) and 36 months after transplantation (mean duration of rhGH-treatment 14 months). 51Cr-EDTA- and PAH-clearances were performed. A protocol renal biopsy was done at 36 months. Growth showed significant improvement during rhGH (P<0.01). One graft loss occurred in both groups. One acute rejection was seen in the control group. There was no difference in the rate pf change in 51Cr-EDTA-or PAH-clearance between the two groups. Histopathological findings were mostly mild. One new onset chronic rejection developed in both groups. Proximal tubular atrophy was more extensive in the rhGH-treated patients (P<0.05), but there was no uniform trend toward more severe findings. RhGH improved growth, and no significant differences were seen in allograft function or histopathology; however, larger trials controlled for pretreatment renal function and immunosuppression are needed.

Acute Disease↗

Distribution of renal integrin receptors and their ligands in congenital nephrotic syndrome of the Finnish type.

The aim of this study was to examine the distribution of beta 1 and alpha v integrins (Ints) and some of their ligands in the kidneys of patients with congenital nephrotic syndrome of the Finnish type (CNF) and in controls using indirect immunofluorescence with monoclonal antibodies. The mesangial reactivity of Int alpha 1 and Int beta 1 subunits was more variable and an increased glomerular reactivity with Int alpha 3 and Int-alpha 6 antibodies was found in CNF kidneys than in controls. Int alpha 2 subunit was either completely missing from or found in significantly lesser amounts in CNF kidney glomeruli. The immunoreactivity for Int alpha v was more variable, fainter and also more granular in CNF samples than in control kidneys. The glomerular reactivity for Int beta 5 was more diffuse and weaker, and in sclerotic Bowman's capsules more intense in CNF kidneys than in controls. Immunoreactivity for Int beta 6 was restricted and was comparable in extent in CNF and control kidneys. Of the extracellular matrix components studied, the expression of EDAFn, EDBFn, OncFn, Ln alpha 2 chain, Ln beta 1 chain and tenascin was increased. This is also seen in several glomerular diseases with inflammation and sclerosis. Immunoreactivity for vitronectin was decreased. Several differences were found in the intensity or location of the immunostaining for the beta 1 and alpha v Ints and their ligands in CNF kidneys compared with controls, which have not been found in any other proteinuric disease. Disturbed Int expression pattern in CNF may specifically reflect the disturbance of glomerular function caused by the primary defect in this disease.

Antibodies, Monoclonal↗

Quality of life in early adolescence: a sixteen-dimensional health-related measure (16D).

While data on the health-related quality of life (HRQOL) of adults are accumulating, very little is known about the HRQOL--and especially the perceived HRQOL--of children. In our study we introduced a 16-dimensional, generic self-assessment measure of HRQOL (16D) for early adolescents, and demonstrated its use with four populations of children aged 12-15: (1) 239 normal schoolchildren, (2) patients waiting for organ transplantation (n = 5), (3) patients with genetic skeletal dysplasias (n = 19), and (4) patients with epilepsy (n = 32). The HRQOL profiles of the patients differed significantly according to the diagnosis, giving support to its construct validity. The reliability of the measure was high: its repeatability coefficient was 91%. The quality of life ratings of the healthy boys and their parents differed on the dimensions of distress, vitality, speech, mental function, and discomfort and symptoms (p < 0.05). In addition, there were significant differences in the health-related valuations between the girls, boys and their parents. We conclude that the assessment of quality of life of adolescents should be based on data collected from the adolescents themselves. Further, the 16D is so far the only generic HRQOL measure designed specifically for this purpose. It is capable of differentiating the HRQOL of healthy adolescents as well as patients with various diagnoses. Our experience also indicates that it is easy to use, yet it seems comprehensive, reliable, and valid.

Adolescent↗

Quality of life in pre-adolescence: a 17-dimensional health-related measure (17D).

Although interest in the health-related quality of life (HRQOL) of children has increased in the last years, validated methods for assessing the HRQOL- and especially the perceived HRQOL-of children have been missing. We introduced a 17-dimensional, illustrated, generic measure of perceived HRQOL (17D) for pre-adolescents, and demonstrated its application to three populations of children aged 8-11 years: (1) 244 normal schoolchildren; (2) 22 patients surviving organ transplantation and (3) 10 patients with genetic skeletal dysplasias. The HRQOL scores and profiles of the patients differed significantly according to the diagnosis, giving support to its construct validity. The reliability of the measure was high: its repeatability coefficient was 95%. As a structured interview of 20-30 minutes, the measurement burden is reasonable. We conclude that the assessment of quality of life of pre-adolescents can and should be based on data collected from the children themselves. Our initial experience indicates that 17D is comprehensive, reliable, and valid.

Bone Diseases, Developmental↗

Chronic rejection and late renal allograft dysfunction.

Renal transplantation is currently standard therapy for end-stage kidney disease for children. Despite the considerable improvement in short-term results, the expected allograft half-life has remained the same. This is due to chronic rejection/late graft dysfunction which has proved resistant to therapeutic attempts. During the last few years the multifactorial pathogenesis of chronic renal allograft rejection has been clarified to some extent. Early injury by immunological and non-immunological mechanisms is followed by vascular remodelling due to repetitive cycles of cytokine release, upregulation of growth factors, and vascular smooth muscle cell proliferation. This leads to typical concentric arteriosclerosis and ischemia. Secondary kidney-specific mechanisms are initiated by the reduction in functioning renal mass and lead to gradual progression of chronic rejection. There is no single optimal therapy. Several attempts to influence the pathophysiological cascade have been promising. Attention should be focused on minimizing early immunological/non-immunological injury in order to attenuate future progression of chronic rejection. A significant prolongation of allograft half-life may be achieved during the next decade with the introduction of new therapeutic agents and comprehensive approach to treatment. This would be especially beneficial for pediatric recipients, reducing the need for retransplantation in adulthood.

Animals↗

Sphingolipid activator proteins in a human hereditary renal disease with deposition of disialogangliosides.

Congenital nephrotic syndrome of the Finnish type is a recessively inherited renal disease with glomerular deposits of the disialoganglioside O-acetyl-GD3. Sphingolipid activator proteins (saposins) stimulate the degradation of glycosphingolipids by lysosomal enzymes, and defects in saposins cause accumulation of substrate lipids in the affected tissues in lysosomal storage disease. Here we report a study of the role of saposins in the accumulation of O-acetyl-GD3 in kidneys of congenital nephrotic syndrome patients. At the mRNA level, the expression of saposin precursor in diseased kidneys appeared normal, and the nucleotide sequence analysis of cDNA clones did not reveal abnormalities in the prosaposin gene. Immunohistologically, saposins were localized mainly to the epithelial cells of the distal renal tubules or to the parietal epithelial cells of glomeruli. In the nephrotic syndrome kidneys, the staining pattern was highly granular and appeared mostly in the apical part of the epithelial lining, unlike the control kidneys. These results show that a major site of ganglioside metabolism is located in the distal nephron. Furthermore, these results suggest that saposins are not directly involved in the metabolism of the terminal sialic acids of disialogangliosides in the nephrotic syndrome kidneys.

Adult↗