Diastolic function and tachycardia in hypertensive children.

We investigated the prevalence and potential predictors of Doppler echocardiographic evidence of diastolic function in untreated hypertensive children. Doppler and M-mode echocardiographic values from 42 children (mean age 13, range 5-17 years) from a pediatric hypertension clinic were retrospectively reviewed and compared to data from 39 age and gender matched normotensive children in a control group. Compared to the participants in the control group, hypertensive patients had increased mean body mass index (29 v 19 kg/M2, P < .0001), peak mitral A velocity (57 v 42 cm/sec, P < .0001), isovolumic relaxation time (65 v 42 msec, P < .0001, resting heart rate (90 v 74 bpm, P < .0001), mitral E deceleration time (150 v 137 msec, P = .006), indexed left ventricular mass index (32 v 26 g/M2.7, P < .0001), relative left ventricular wall thickness (0.32 v 0.29, P = .02), and decreased ratio of peak mitral E velocity/peak mitral A velocity (1.7 v 2.1, P = .0001). Mean age, height, mitral E velocity, mitral A deceleration time, fractional shortening, and indexed left ventricular diastolic dimension were similar in patients and control group children. In the hypertensive patients, multivariate analysis demonstrated that heart rate (P = .0008) and systolic blood pressure (P = .03) were significant predictors of peak A velocity. In addition, heart rate (P = .0003), body mass index (P = .04), and indexed left ventricular diastolic dimension (P = .04) predicted the ratio of peak E/peak A velocity. None of the measures of diastolic function correlated with left ventricular mass index or relative wall thickness. Furthermore, none of the analyzed variables predicted isovolumic relaxation time or mitral E deceleration time. We conclude that untreated hypertensive children have Doppler indices suggestive of impaired left ventricular relaxation. Resting heart rate was the strongest predictor of abnormal diastolic indices.

Ureteral urine leak presenting as a pleural effusion in a renal transplant recipient.

We report a 15-year-old girl who developed a ureteral perforation soon after living-related donor renal transplantation. Her presentation was unusual in that a symptomatic pleural effusion accumulated as an extension of the perinephric urine collection. Recognition and surgical correction of the ureteral pathology led to resolution of respiratory symptomatology and full recovery of renal function.

Early occurrence of end-stage renal disease in a patient with infantile nephropathic cystinosis.

We report the case of a patient with infantile nephropathic cystinosis who required renal transplantation at age 30 months. Exhaustive evaluation did not identify a cause of progressive renal failure other than cystinosis. The patient's genetic lesion was allelic with those of other patients with cystinosis; fusion of this patient's fibroblasts with fibroblasts from another patient with infantile nephropathic cystinosis did not demonstrate complementation of the biochemical defect.

Imaging the urinary tract.

Since the advent of US, nearly every malformation of the urinary tract has been diagnosed in utero. Physiologic dilatation of the renal pelvis occurs and can be misdiagnosed as hydronephrosis, so the normal gestational development of the urinary tract, and its visualization by ultrasound, should be understood. Gestational diagnosis is important for family counseling, collaboration of the perinatal team, and for determining both the future evaluation needs and the possibility of intervention. Those infants at high risk, as well as others who have specific signs and symptoms of possible urinary tract disease, deserve prompt and careful postnatal imaging studies. Ultrasonograms may be combined with other imaging modalities in specific circumstances to provide accurate diagnoses and some functional information.

Renal transplantation for systemic lupus erythematosus and recurrent lupus nephritis. A single-center experience and a review of the literature.

Prior to 1975 patients with systemic lupus erythematosus were generally not considered candidates for renal transplantation because of concern that immune complex deposition would rapidly destroy the allograft. However, recent evidence suggests that good patient and graft survival rates can be achieved comparable to other renal diseases. Between September 23, 1963 and July 31, 1990, 1070 renal transplants were performed at Washington University Medical Center (WUMC). During this period, 14 patients with SLE (12 female and 2 male) received 16 renal transplants (7 living-related donor [LRD], 1 living-unrelated donor [LURD], and 8 cadaver [CAD]). The mean age at the time of the first transplant was 32.5 +/- 10.3 years. The duration of disease prior to transplant was 88.0 +/- 45.9 months and the duration of hemodialysis prior to transplant was 36.0 +/- 33.7 months. Of these patients, 7/14 (50%) had negative and 3/14 (21%) positive SLE serology pre- and post-transplant, 3/14 (21%) had negative serology pretransplant that became positive posttransplant, and 1/14 (2%) was positive pretransplant and became seronegative posttransplant. Patient survival was 92.8% (13/14), and of the 16 kidneys transplanted 62.5% (10/16) are still functioning with a mean follow-up period of 43.7 +/- 45 months. The current mean serum creatinine was 1.4 +/- 0.26 mg/dl. One noncompliant patient developed recurrent lupus nephritis bringing the total number of cases reported in the literature to seven. The present study demonstrates that patients with SLE can be transplanted with excellent patient and graft survival and function and a low rate of recurrent lupus nephritis. From a review of the literature, there appears to be an association between positive SLE serology pre- and posttransplant and recurrent lupus nephritis.

Familial renal adysplasia.

Renal dysplasia and agenesis as isolated findings are usually considered sporadic, noninherited abnormalities. We report three kindreds with familial renal adysplasia. Two or more children were affected in each of the families and at least one member--whether proband, sibling, or parent--had a clinically silent anomaly. Normal kidneys in the parents did not preclude the occurrence of renal adysplasia in more than one child. The empiric risks for offspring and first-degree relatives were 50% and 25%, respectively, suggesting a strong genetic factor such as a major dominant gene with variable expression. Because the disease appears to be genetic in some cases of renal adysplasia, careful screening of the proband's family, subsequent children, and pregnancies is important for the purpose of accurate genetic counseling.

The psychosocial implications of pre-emptive transplantation.

Pre-emptive (primary) renal transplantation is occurring with greater frequency as pediatric transplant centers attempt to initiate renal replacement therapy at a time best designed to optimize growth and development in children. Psychosocial benefits of performing pre-emptive transplant are highlighted by an intervention before the child has symptoms of uremia and, thus, develops a self-image as a "sick patient with end-stage renal disease", avoidance of dependence on machine technology, avoidance of a change in parenting that may occur with fears about dialysis, and maintenance of an orientation toward future goals. In addition, the child will likely have less loss of school time and less disturbance in previously established social patterns. Difficulties that may be enhanced in pre-emptive transplantation arise from potentially decreased involvement of the child and family in the medical (transplant) care system prior to transplantation. The two major issues of concern are: (1) optimal education regarding patient (family) responsibility toward quality care of the graft recipient; (2) the accurate assessment of coping skills coupled with the development of optimum psychosocial support from the health care workers and community support services. The provision of a good educational and supportive program is time consuming and financially draining. We must develop creative approaches to these areas in order to enhance each child's opportunity for family and community interaction, as well as physical well-being.

HLA extended haplotypes in steroid-sensitive nephrotic syndrome of childhood.

Idiopathic nephrotic syndrome has been postulated to have an immunopathogenic basis. To determine whether steroid-sensitive nephrotic syndrome is associated with greater than expected frequencies of specific extended haplotypes of the major histocompatibility complex, we studied genetic markers (Class I, II, III HLA alleles and glyoxalase I) in 173 subjects in 42 families of patients with nephrotic syndrome of childhood. The single allele, DQW2, was found in 72% of steroid sensitive patients compared with only 35% of the controls (P = 0.003). In half of 32 steroid sensitive, but not 10 steroid resistant, patients, one or both of two specific extended haplotypes (alleles that segregate together) were identified. The first, [HLA-A1, B8, DR3, DRW52, SCO1], occurred in 11 of 64 haplotypes, or 17%, compared to 5% of controls (P = 0.017). The other, [HLA-B44, DR7, DRW53, FC31], occurred in 10 of 64 haplotypes, 16% compared to 3.8% of controls (P = 0.014). Five patients had both haplotypes. Patients with these specific extended haplotypes had a greater frequency of relapses than did those with other haplotypes. These data provide additional support for the hypothesis that steroid-sensitive nephrotic syndrome has an immunogenetic basis.

Progressive enzyme changes within anatomically defined segments of rabbit nephron: demonstration with a new technique.

The kidney is an extremely heterogeneous organ, with morphological, physiological, and metabolic changes occurring from segment to segment along each nephron. To determine the heterogeneity that might exist within discrete anatomical segments of rabbit nephron, we developed a technique for making quantitative enzyme assays in serial samples, about 100 micron long, along identified segments of the nephron. Results for three enzymes in proximal convoluted and straight tubules show that adenylate kinase, an enzyme of high-energy phosphate metabolism, gradually decreases along the S1 and S2 segments of the proximal tubule, with no abrupt changes. Fructose bisphosphatase, a gluconeogenic enzyme, is high along the major portion of the proximal tubule but plummets along the final millimeter of S3. Conversely, phosphofructokinase, a glycolytic enzyme, is very low along the proximal tubule but increases sharply within the final millimeter. These data underscore the biochemical heterogeneity of the nephron, illustrating the enzyme levels may change markedly even within anatomically defined regions. They also suggest the importance of further studies of this type and demonstrate a practical means for such studies.

Sonographically detectable cysts in polycystic kidney disease in newborn and young infants.

Autosomal dominant (adult type) and autosomal recessive (infantile type) polycystic kidney disease are 2 distinct forms of hereditary cystic renal disease with differing pathologic and clinical features. Glomerulocystic kidney disease is probably a separate entity, whose pathologic features may closely resemble those of autosomal dominant polycystic kidney disease, especially in small infants. An example of each of these conditions in a small infant is presented, all of which had sonographically detectable cysts. Pathologic correlation was available in each case. While there are typical sonographic features of autosomal dominant and autosomal recessive polycystic kidney disease in newborn and young infants, there is no specific appearance of either condition, and glomerulocystic kidney disease can apparently resemble either one. Other investigations, particularly family studies and pathologic verification, are important in order to establish the correct diagnosis.

Polycystic kidney disease in the first year of life.

To determine the frequency of autosomal recessive and autosomal dominant polycystic kidney disease (PKD) in infants and to compare the rate of progression of these conditions, we conducted a retrospective survey of 48 patients who were seen with PKD before 1 year of age and who survived the first month of age. Seventeen patients had recessive PKD; six had dominant PKD. Eighteen patients had insufficient data to categorize the type of PKD with certainty. Seven patients were classified as "other"; three had glomerulocystic disease and the remainder had multiple malformation syndromes or tuberous sclerosis. Renal ultrasonography and excretory urography accurately detected 15 of 17 patients with recessive PKD, but only one patient with dominant PKD was correctly diagnosed by excretory urography. The majority of patients in all groups required antihypertensive therapy. The 17 children with recessive PKD have been followed up for 6.1 +/- 4.3 (SD) years. Eight patients are doing well. Two patients have died; five others have required treatment for renal failure. Only one patient has an estimated glomerular filtration rate within the normal range after 6 years of age. Long-term evaluation of most of the patients with dominant PKD is not yet available; however, by age 42 months one patient has required dialysis. To provide optimum genetic counseling and accurate diagnosis for patients with PKD, a combination of careful family evaluation, radiography, and liver or kidney biopsy is required. The outcome of patients who survive the neonatal period appears not to be so grim as previously feared, underscoring the importance of aggressive supportive care and the need for physician and family education.

Developmental changes in the rat atriopeptin hormonal system.

We undertook a study of fetal synthesis, storage, and release of atriopeptin (AP). Plasma levels of both atriopeptin immunoreactivity (APir) and the NH2-terminal fragment of the prohormone immunoreactivity (NTFir) were very high in the fetus (4 and 20 times the maternal plasma, respectively). However, the atrial content of the AP was low, but surprisingly, ventricular content of AP was quite high (relative to the adult) in the fetus and fell postnatally. Atrial AP messenger RNA (mRNA) increased with postnatal age, whereas ventricular mRNA was extremely high in the fetus and fell rapidly after birth. High fetal plasma peptide levels may derive from the mother since infusion of exogenous atriopeptin 24 into the mother resulted in parallel increases in fetal and maternal peptide levels. Fetal plasma APir and NTFir levels partially reflect the markedly reduced total renal metabolic capacity compared with that of the adult. Plasma levels fell progressively after birth; whereas neonatal atrial content rose substantially. Plasma AP and NTF were simultaneously elevated in both the maternal and fetal circulation after vasopressin injection of the mother. The fetus can also respond to exogenous stimuli (vasopressin or indomethacin--presumably via ductal closure) and promptly release substantial amounts of peptide into its circulation. Thus, it appears that the AP hormonal system is functional during fetal life and responds avidly to increases in intracardiac pressure as does the mature animal.

The involvement of atriopeptins in blood pressure regulation.

The atriopeptins are newly discovered cardiac-derived peptides whose observed actions suggest a role in volume homeostasis and blood pressure regulation. Studies in animal models are underway to pinpoint pathogenetic mechanisms involved in the evolution of hypertension, some of which may well be shared by humans with "essential" hypertension. Preliminary observations indicate that circulating atriopeptin levels are altered in human disease. It is anticipated that exogenously administered atriopeptin may be a helpful pharmacological tool in the management of patients with volume overload and hypertension.

Atriopeptins: circulating volume regulatory hormones with potential therapeutic role in chronic renal failure.

Sprague-Dawley rats given bolus intravenous injections of vasoconstrictors, including 1-deamino-Arg8-vasopressin (dAVP), demonstrated remarkable increases in plasma immunoreactivity (APir) to atriopeptin (AP). These elevations were accompanied by increases in systemic blood pressure, right atrial pressure and urinary volume excretion. Fractionated plasma APir peaks obtained by stimulation with dAVP were identified as primarily AP 28, with a smaller amount of AP 24, suggesting that AP 28 is the predominant circulating atrial peptide. Rats with reduced renal mass have increased single-nephron glomerular filtration rates (GFR). Despite these increases, AP 24 stimulated a marked increase in total GFR and promoted a profound natriuresis and diuresis. Atriopeptin 24 may therefore have potential as a therapeutic tool in the management of volume overload in chronic renal failure.