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Biomedical subjects

H J Baluarte

Publications and source records attributed to H J Baluarte.

At least 19 recordsLinked to original sources

Risk factors for hyperlipidemia in long-term pediatric renal transplant recipients.

Hyperlipidemia (HL) is a common problem in adult renal transplant (TP) recipients, contributing to an increased risk of cardiovascular disease and chronic TP nephropathy. There are multiple causes of HL post renal TP in adult patients, including pre TP HL, immunosuppressive agents, renal dysfunction, hypoalbuminemia secondary to nephrotic syndrome, obesity, and conditions that lead to end-stage renal disease (ESRD). We evaluated the incidence and risk factors of HL in 62 pediatric renal TP recipients (15.4+/-4.2 years, range-3.0-22.3 years) with long-term (6.7+/-3.1 years) functioning [glomerular filtration rate (GFR) 66.7+/-23.2 ml/min per 1.73 m(2)] allografts. The mean serum cholesterol (C) level was 205. 5+/-43.6 mg/dl. Thirty-two patients (51.6%) exhibited elevated serum C levels. The mean serum triglyceride (TG) level was 157.3+/-88.4 mg/dl. Serum TG levels were elevated in 32 patients (51.6%). In patients with elevated serum levels of either C or TG, the mean low-density lipoprotein level (LDL) was 138.6+/-44.1 mg/dl (normal <130 mg/dl) and the high-density lipoprotein (HDL) level 54.6+/-15.9 mg/dl (normal>34 mg/dl). Of those patients studied, 45.5% had high LDL levels, whereas 9.1% exhibited low HDL levels. The two risk factors for elevated serum C levels in our patient population were pre-TP HL and increased years since TP. The only risk factor for elevated serum TG levels was reduced GFR. A family history of HL had a significant deleterious impact upon serum levels of C (P=0.01), but did not affect serum TG levels (P=0.7). Years on dialysis prior to TP, history of prior TP, gender, body mass index, and disease leading to ESRD had no influence upon the development of post-TP HL. We conclude that post-renal TP HL is a significant problem in pediatric renal TP recipients.

Adolescent↗

Adverse effects of mycophenolate mofetil in pediatric renal transplant recipients with presumed chronic rejection.

BACKGROUND: Mycophenolate mofetil (MMF) has been shown to be superior to azathioprine in reducing the incidence of acute rejection in adult renal transplant recipients. Although MMF is also being widely used in pediatric transplant patients, data documenting its safety are limited. METHODS: A retrospective review of the transplant records at St. Christopher's Hospital for Children was conducted to identify patients who had received MMF. RESULTS: Twenty-four children were switched from azathioprine to MMF, 4.8+/-2.9 years after transplantation. After an additional 0.8+/-0.4 years, MMF had been discontinued in 13 patients (54%) because of adverse effects (AE). The only variable that predicted the development of AE was a lower calculated creatinine clearance at the time of initiation of MMF. CONCLUSIONS: In pediatric renal transplant recipients with impaired renal function, the use of MMF at the recommended dose is associated with an unacceptably high incidence of AE; in such patients, the MMF dose may require modification for the level of renal function.

Adolescent↗

Anti-lymphocyte antibodies late in the course of pediatric renal transplantation.

Beyond the immediate post-transplant period, physicians are often reluctant to use anti-lymphocyte preparations to treat episodes of acute renal functional deterioration attributable to acute rejection. This is due to the perception that such episodes are less likely to be reversible, and to concern regarding the potential adverse effects of anti-lymphocyte antibodies, including opportunistic infections, lymphoproliferative disorders, and the development of human anti-mouse antibodies. Records were reviewed for all 365 renal transplants performed in 267 patients at our center from 1971 to 1996. Anti-lymphocyte antibodies were used in an attempt to reverse 6 episodes of corticosteroid-resistant acute rejection in 5 children at a mean interval of 24.5 months following transplantation. The mean serum creatinine at initiation of therapy with the anti-lymphocyte agents was 2.9 mg/dl. Following treatment, the mean serum creatinine decreased to 1.3 mg/dl (P=0.03, Student's t-test). Two patients developed uncomplicated opportunistic infections after completion of anti-lymphocyte therapy; none have developed lymphoproliferative disorders or antibodies to OKT3. We conclude that in the correct clinical setting with corticosteroid-resistant acute rejection, the use of anti-lymphocyte antibodies should not be withheld solely on the basis of length of time since transplantation.

Adolescent↗

Use of calcium-channel blockers in pediatric renal transplant recipients.

Hypertension (HTN) is a significant problem in pediatric renal transplant (TP) recipients, predisposing the individuals to the development of cardiovascular disease and graft dysfunction. Calcium channel blockers (CCB) are considered excellent agents to treat post-TP HTN. We compared the efficacy and adverse effects of the two most commonly prescribed CCBs in our pediatric renal TP population: nifedipine (Procardia, or P) and amlodipine (Norvasc, or N). All patients (n = 24) had been started on a CCB for systolic (SBP) and/or diastolic BP (DBP) > 95%. There were no other changes in adjunctive antihypertensive medications or doses during the cross-over period. Post-TP, pretreatment (pretx) SBP was 137.6 +/- 10.9 mmHg. The post-treatment SBP were (in mmHg): 128.5 +/- 11.9 (all patients, n = 24) (p = 0.009 vs. pretx); 126.4 +/- 10.0 (P alone, n = 15) (p = 0.007 vs. pretx); 132.8 +/- 14.4 (P + other antihypertensive(s), n = 9) (p = 0.331, NS vs. pretx). The post-TP, pretreatment DBP was 88.2 +/- 11.1 mmHg. The post-treatment DBP were (in mmHg): 78.5 +/- 6.9 (all patients, n = 24) (p = 0.03 vs. pretx); 77.2 +/- 7.4 (P alone, n = 15) (p = 0.008 vs. pretx); 80.7 +/- 6.1 (P + other antihypertensive(s), n = 9) (p = 0.063, NS vs. pretx). P and N were equally effective in reducing SBP (p = 0.843, NS) and DBP (p = 0.612, NS). Cyclosporin A (CyA) dose (p = 0.81) and trough levels (p = 0.19) were similar in P- and N-treated patients. Calculated GFR was virtually identical in P- and N-treated patients (p = 0.89). Patients (or parents of) reported a higher incidence of various side-effects while receiving P, including headache, flushing, dizziness and leg cramps. Furthermore, 22/24 (91.7%) reported some degree of gingival hyperplasia during treatment with P, and all these patients reported a stabilization or reduction of hypertrophy after the switch from P to N. We conclude that CCBs (N) are efficacious drugs for the purpose of BP control and renal protection in pediatric renal TP recipients.

Adolescent↗

Predictive value of race in post-transplantation recurrence of focal segmental glomerulosclerosis in children.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is a leading cause of end-stage renal disease (ESRD) in children, and one of the most difficult to manage because of its high recurrence rate post-transplantation (Tx). Several predictive factors have been associated with disease recurrence (DR) although one in particular, the role of recipient race, has not been adequately evaluated. Herein we report our experience with DR in the post-Tx period in eight patients. METHODS: Records were reviewed for all renal transplants performed at St Christopher's Hospital for Children from 1971 to 1997. RESULTS: Twenty patients received 27 allografts for ESRD due to FSGS. Ten (37%) grafts went to African-American (AA) children, and 16 (59%) to those of Caucasian (C) origin. DR was observed in eight (30%) grafts after Tx. No differences were noted between the patients who developed DR and those who did not, with respect to age at diagnosis or time to ESRD. DR was observed in one (10%) of 10 grafts in AA, compared to seven (41%) of 17 grafts in the other (O) racial groups (P=0.19). At last follow-up, the only AA recipient with DR has maintained stable renal function, while three (43%) of seven in O have lost their grafts. CONCLUSION: In conclusion, in our population post-Tx recurrence of FSGS occurred more frequently and represented a greater threat to graft survival in O recipients than in those of AA descent. Recipient race should therefore be taken into consideration during pre-Tx counselling of families of children with FSGS.

Adolescent↗

Pleural effusion complicating acute peritoneal dialysis in hemolytic uremic syndrome.

Hemolytic uremic syndrome (HUS) is a leading cause of acute renal failure (ARF) in children, and one for which treatment with peritoneal dialysis (PD) is often necessary. Between January 1982 and December 1996, 176 children received PD for ARF at St. Christopher's Hospital for Children; 34 (19%) of whom had HUS. Of these 34, 7 (20%) developed pleural effusions (PE) while receiving PD, whereas none of the remaining 142 children with other causes of ARF did so. The mean age of the 7 affected children was 5.2 (range 0.4-17) years; none had heart failure or nephrotic syndrome, nor had any of them undergone thoracic surgery. PE were diagnosed by chest radiograph at an interval of 2 (range 1-3) days after starting PD. Thereafter, 4 (57%) patients were successfully maintained on a modified PD prescription; 2 others were converted to hemodialysis and 1 to continuous venovenous hemodiafiltration. Although PE are a known complication of PD, none of the patients so treated for non-HUS related ARF developed them. Whether they represent a purely mechanical complication of PD, or are in some way attributable to HUS itself, is not entirely clear. Regardless, when children with HUS require PD, physicians should monitor for the development of this potential complication to minimize the risk of serious respiratory compromise.

Acute Kidney Injury↗

Calcineurin activity in children with renal transplants receiving cyclosporine.

BACKGROUND: The major immunosuppressive effect of cyclosporine is through the inhibition of calcineurin, an enzyme important in the activation of T lymphocytes. In children, neither calcineurin activity nor its inhibition by cyclosporine (CsA) has been investigated. METHODS: Calcineurin activity, was measured in stable pediatric renal transplant patients, with healthy children used as controls. Whole blood CsA concentrations were measured by monoclonal radioimmunoassay. Simultaneous calcineurin and CsA levels were measured before and 1, 2, 3.5, 5, and 12 hr after their routine morning CsA dose. RESULTS: Calcineurin activity was approximately 50% inhibited at trough blood concentrations (148 microg/L); moreover, inhibition increased as CsA concentrations rose and declined as concentrations fell. Maximum calcineurin inhibition was about 70% at concentrations of about 431 microg/L. Linear regression analysis revealed a significant correlation between mean CsA blood concentration and the mean degree of inhibition of calcineurin activity (P=0.005, one-tailed). CONCLUSION: We conclude that inhibition of calcineurin activity by CsA in pediatric renal transplant recipients correlates with CsA blood concentrations.

Adolescent↗

Response to the varicella vaccine in children with nephrotic syndrome.

Varicella vaccine was administered to seven children with corticosteroid-sensitive nephrotic syndrome. Immunization was not associated with any significant reactions or with increased frequency of relapse. The antibody response was, however, variable and a second dose was necessary before seroconversion was achieved in four patients. The findings indicate that immunization with varicella vaccine is safe in children with nephrotic syndrome in remission, but that a two-dose vaccine schedule should be considered.

Antibodies, Viral↗

Intravenous immunoglobulin prophylaxis of cytomegalovirus infection in pediatric renal transplant recipients.

Cytomegalovirus (CMV), the most significant infectious cause of morbidity following renal transplantation, may be a greater problem for children than for adults due to their relative lack of experience with this virus. Therefore, we prospectively gave Gammagard as prophylaxis to CMV-negative children who received CMV-positive allografts and compared the results to our experience with similar high-risk recipients transplanted prior to our use of intravenous immunoglobulin G (IvIgG). Symptomatic CMV disease developed in 17% of the IvIgG recipients as compared with 71% of the untreated patients (p = 0.01). The CMV infections that did occur in IvIgG recipients developed significantly later than in untreated children (median time of onset after transplantation 2.60 vs. 1.35 months; p < 0.05) and generally were less severe, although 1 IvIgG recipient died despite prophylaxis. IvIgG administration did not affect the frequency of rejection or graft or patient survival. We conclude that IvIgG administration to high-risk pediatric renal transplant recipients may protect against posttransplantation CMV disease and may lessen the severity of infections that do develop in patients who receive it.

Child↗

Pharmacokinetics of cyclosporine after renal transplant in children.

The pharmacokinetics of cyclosporine and the relationship between blood levels and average drug concentration were prospectively evaluated in 18 children 1 month after renal transplantation. All children had normal renal function and no hepatic or gastrointestinal dysfunction. Cyclosporine was administered after an overnight fast, and serial blood samples were drawn over a 24-hour period. Analysis of cyclosporine levels was performed by means of monoclonal radio immunoassay on whole blood. Children were divided into three age groups for comparison: 2-5 years, 5-10 years, and > 10 years. There were no differences between age groups in serum protein, serum lipids, or hemoglobin levels, or in the pharmacokinetic parameters of cyclosporine except as follows: significant differences were noted in cyclosporine dose based on body weight, apparent steady-state volume of distribution, and apparent blood clearance, with the youngest children (2-5) requiring higher doses, a relative greater distribution, and exhibiting more rapid drug clearance than those > 10 years of age. In addition, we observed diurnal variation in trough levels, with morning levels (0 hr) significantly higher than those obtained in the evening (12 hours after administration of cyclosporine). Trough levels demonstrated a fair correlation with area under the concentration-time curve (AUC) and average concentration (Cav), but an abbreviated kinetic profile using cyclosporine levels 1 and 3.5 hours after administration accurately predicted AUC.

Adolescent↗

Effective immunization against influenza in pediatric renal transplant recipients.

Viral infections such as influenza are an important cause of morbidity following organ transplantation. We evaluated the immunogenicity of a commercially available influenza vaccine in pediatric renal transplant recipients in a two-phase, prospective study. In phase one, 47 transplant patients and seven control subjects with bronchopulmonary dysplasia received influenza vaccine. Sera were collected at the time of vaccination and 6 wk later. In phase two, sera from 18 transplant recipients and 47 healthy adults who had received the same vaccine were collected 6-12 months after vaccination. Antibody titers to the A/Taiwan/1/86 antigen were measured with hemagglutination inhibition assay in both phases of the study. Vaccine was well tolerated in all subjects. No vaccinated patient required hospitalization for complications of influenza infection. Vaccination did not increase the frequency of acute allograft rejection. In phase one, 43 patients (91%) and 5 controls (71%) either seroconverted (developed a fourfold or greater rise in titer), or developed post-vaccination titers > or = 1:160 (p = NS). Among the transplant recipients, non-seroconverters had a higher pre-vaccination geometric mean antibody titer (GMT) than those who seroconverted. Seroconversion developed independently of whether patients received double or triple immunosuppression. In phase two, post-vaccination GMT were similar for patients and control subjects at 11.5 and 8 months post-vaccination, respectively. In our study, influenza vaccination produced equivalent humoral immunity in transplant recipients and normal subjects. Routine influenza vaccination should be performed annually in this high-risk population.

Adjuvants, Immunologic↗

Natural history and etiology of hyperuricemia following pediatric renal transplantation.

A retrospective review was conducted to determine the incidence, etiology, natural history and complications of hyperuricemia after pediatric renal transplantation. Of 81 active transplant recipients aged 10.1 +/- 4.8 (mean +/- SD) years being followed by St. Christopher's Hospital for Children, 57 (70%) were males and 59 (73%) Caucasian. Their immunosuppression consisted of azathioprine, cyclosporine A and prednisone. Mean serum uric acid concentrations peaked at 6 months post transplantation (6.2 +/- 2.6 mg/dl), when 39% of the patients had hyperuricemia and 60% were receiving diuretics, and decreased thereafter. At 30 months, 23% of the patients had hyperuricemia and 17% required diuretics. When we compared 42 normouricemic (group A) with 24 hyperuricemic (group B) patients at 18 months post transplantation, we found that patients in group B were older (11.6 +/- 4.2 vs. 8.6 +/- 5.2 years, P = 0.01), had worse renal function (77 +/- 25 vs. 96 +/- 36 ml/min per 1.73 m2, P = 0.03) and required diuretics more frequently (63% vs. 21%, P = 0.001), but had identical blood levels of cyclosporine A (82 +/- 28 vs. 84 +/- 35 ng/ml, P = 0.78). A family history of gout did not affect the prevalence of hyperuricemia after transplantation. Asymptomatic hyperuricemia is common following pediatric renal transplantation and is more likely attributable to reduced renal function and diuretic therapy than to the known hyperuricemic effect of cyclosporine A. Of these variables, only diuretic therapy is readily controllable and should be closely regulated following pediatric renal transplantation.

Aging↗

Effect of rifampin on Staphylococcus aureus colonization in children on chronic peritoneal dialysis.

The efficacy of rifampin in eliminating Staphylococcus aureus colonization was evaluated in a pediatric peritoneal dialysis population. Six children with documented nasal colonization were treated for 7 days with rifampin and cloxacillin. Although antimicrobial therapy eliminated nasal carriage in all patients, recolonization occurred in 66%. Exit site colonization proved difficult to eradicate with negative cultures documented in only 3 of 5 children after rifampin/cloxacillin therapy. Although S. aureus carriage is a risk factor for S. aureus infections, efforts to eradicate carriage with rifampin are hindered by rapid recolonization.

Antibiotics, Antitubercular↗

The relationship between calcium, phosphorus, and sodium intake, race, and blood pressure in children with renal insufficiency: a report of the Growth Failure in Children with Renal Diseases (GFRD) Study.

Nutritional data compiled during the Growth Failure in Children with Renal Diseases Clinical Trial were analyzed to determine the relationship between the dietary intake of divalent minerals and sodium, nutritional status, and serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations and blood pressure in black versus white children. One hundred eighteen patients are included in this report; 25 were black (21%) and 93 were white (79%). Although more of the blacks were male, the age distribution, midarm circumference, midarm muscle circumference, blood pressure, and serum calcium, phosphorus, and PTH concentrations were comparable in the two groups. Phosphorus intake was within the recommended daily allowance in both groups; in contrast, calcium intake was inadequate in all patients: 81% of the recommended daily allowance in whites, and 74% in blacks. Sixteen children were noted to be hypertensive during the observation period; six patients were receiving a variety of antihypertensive medications, including diuretics in two children. Linear regression analysis revealed that systolic and diastolic blood pressures were directly related to calcium and phosphorus intake in black patients. In white children, only dietary phosphorus intake and diastolic blood pressure were directly related. There was no relationship between sodium intake or GFR and blood pressure in the white or black children. PTH levels were directly correlated with systolic and diastolic blood pressure in all children. The correlations between PTH and blood pressure were stronger in white versus black patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Black People↗

Analysis of hypertension in children post renal transplantation--a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS).

Hypertension is common in children after renal transplantation and is associated with multiple factors. Data regarding the prevalence of post-transplant hypertension and the relationship between immunosuppressive drugs and the persistence of hypertension in a large population of North American children have not been available. This study was designed by the North American Pediatric Renal Transplant Cooperative Study to evaluate in a large diverse multicenter population of children the prevalence of hypertension post transplantation, the type of antihypertensive medications used to treat this hypertension and to determine the relationship between the blood pressure control and the immunosuppressive therapy. Analysis of 277 patients showed the following: (1) 70% of recipients required antihypertensive medications 1 month post transplant compared with 48% pre transplant; the incidence decreased to 59% at 24 months; (2) the majority of children received multiple drug therapy to control blood pressure; (3) hypertension can be controlled effectively despite inherent etiological factors, such as allograft source, prior hypertension and immunosuppressive therapy.

Adolescent↗

Growth after conversion to alternate-day corticosteroids in children with renal transplants: a single-center study.

During the 1980s all children with growth potential and stable/adequate renal function at 6-9 months after kidney transplantation underwent conversion to alternate-day corticosteroids in an attempt to maximize growth. Conversion was attempted in 79 of 160 children who received allografts during this decade and was considered successful if they remained on alternate-day prednisone for more than 1 year, with a calculated creatinine clearance of at least 75% of the pre-conversion baseline value. Conversion succeeded in 55 children but failed in 24. Growth was markedly improved among those successfully converted when compared with the failure group, as measured by standard deviation score for growth velocity based on chronological age (+0.94 +/- 1.58 vs. -0.86 +/- 1.53, P < 0.001) and bone age (+0.49 +/- 0.61 vs. -1.24 +/- 1.47, P < 0.001). The improved growth among the successfully converted patients is believed to have been related to the combined effects of lower corticosteroid dose (0.36 +/- 0.16 vs. 0.48 +/- 0.21 mg/kg per day, P < 0.02) and better renal function (calculated creatinine clearance 87 +/- 32 vs. 47 +/- 21 ml/min per 1.73 m2, P < 0.001) at 1 year post conversion. Two factors appeared to improve the likelihood of successful conversion: the use of cyclosporine and receiving a live-related rather than cadaver transplant. Cyclosporine was associated with improvement in the overall rate for successful conversion in all recipients, from 59% to 83% (P < 0.05). Recipients of allografts from live-related donors underwent successful conversion in 90% of cases compared with 58% receiving cadaver allografts (P < 0.05). (ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Peritoneal dialysis catheter infections in children after renal transplantation: choosing the time of removal.

As a foreign body, the peritoneal dialysis (PD) catheter represents a potential source of infection, particularly for immunosuppressed renal transplant patients. A retrospective study was therefore undertaken to compare the risks and benefits of our policy of removing PD catheters at 3 months following renal transplant, which was established to allow for early re-initiation of dialysis. Between 1984 and 1990, 43 renal transplants were performed in 35 children who had been receiving maintenance PD. During the 1st month post transplantation, the PD catheter was used in 25 patients (58%) because of acute rejection or primary allograft non-function. Thirty-one patients were eventually discharged with functioning allografts and a PD catheter in place. Of them, 43% developed a catheter-related infection within the next 2 months, a period during which PD was not performed. Potential contributing factors included a history of catheter-related infection prior to transplantation, use of high-dose methylprednisolone to treat acute rejection, and the type of maintenance immunosuppression prescribed; conversely, the use of prophylactic antibiotics appeared to decrease this risk. This study established the potential need for the catheter during the first few weeks, but because of the infection risk of 43% by 3 months post transplantation, our protocol was revised to include catheter removal at the time of hospital discharge. From 1990 until the end of 1992, an additional 19 PD recipients underwent transplantation. In this group, catheters were used during the 1st month in 6 children (32%). Fifteen patients were discharged with a functioning allograft and only 1 patient returned to PD at 12 months post transplant. It is concluded that PD catheters represent an additional source of infection following transplantation and should be removed at the time of hospital discharge, after which the likelihood of use is low.

Anti-Infective Agents↗