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Biomedical subjects

B Chavers

Publications and source records attributed to B Chavers.

At least 19 recordsLinked to original sources
PubMed2001

Risk factors for cardiovascular disease in children on maintenance dialysis.

Cardiovascular disease mortality is high in children on maintenance dialysis, accounting for about 25% of patient deaths. Cardiovascular-related mortality rates for children on dialysis are higher than for children with successful kidney transplants. Data on the long-term consequences of risk factors for cardiovascular disease are lacking for pediatric end-stage renal disease patients. This article reviews pediatric data pertaining to the following risk factors: anemia, hypertension, hyperlipidemia, left ventricular hypertrophy, abnormal calcium-phosphorus metabolism, and hyperhomocysteinemia. The potential relationship of end-stage renal disease to the etiology of several functional disorders of the cardiovascular system is discussed. Clinical studies are needed to assess the prevalence of cardiovascular disease and of cardiovascular disease risk factors in the pediatric end-stage renal disease population. Possible preventive and therapeutic guidelines need to be developed for at-risk children on maintenance dialysis.

Cardiovascular Diseases↗
PubMed2000

Continuing improvement in cadaver donor graft survival in North American children: the 1998 annual report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS).

This report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) covers the years 1987-1997, and analyses data on 3,133 cadaver donor (CD) transplants performed in 2,736 patients. There has been a steady decline in the number of CD transplants in children since 1996. Kidneys recovered from donors under 10 years of age accounted for 35% of all transplants in 1987, whereas by 1996 they comprised less than 20%. Caucasian children received 54% of CD transplants, whereas African-American children received 21%. Children under 6 years of age received 17% of CD transplants. Approximately half (46%) of the patients were induced with a T-cell antibody, and at 7 years post-transplant triple therapy is used in 70% of those with a functioning graft. Cyclosporin A is the primary immunosuppressant, with 92% of the patients being maintained on it at 5 years post-transplant. Among patients receiving a transplant in 1997, 11% were initiated with another calcineurin inhibitor, tacrolimus. At 15 days post-transplant 20% of the patients have had a rejection episode and by day 45, 46% have had an acute rejection. The probability of developing a rejection within the first year was reduced from 71% in 1987-1988 to 47% in 1995-1996.

Adolescent↗
PubMed1999

Clostridium difficile colitis after kidney and kidney-pancreas transplantation.

OBJECTIVE: To determine the timing and risk factors involved in the development of Clostridium difficile (CD) colitis in kidney and kidney-pancreas transplant recipients. BACKGROUND DATA: The incidence of CD colitis after kidney and kidney-pancreas transplantation has not been studied in detail. The question of whether the immunosuppressed transplant recipient is more prone to CD colitis and its complications (i.e., megacolon, perforations) and the risk factors involved have not been determined. METHODS: We retrospectively reviewed our experience in kidney and kidney-pancreas recipients who received transplants between January 1, 1985 and December 31, 1994. We divided these recipients into three groups: pediatric kidney recipients, adult kidney recipients, and kidney-pancreas recipients. For each group, we assessed the timing of infection, primary disease, colitis treatment, and any concurrent complications or risk factors. RESULTS: Of 1932 transplants, 159 recipients developed post-transplant CD colitis. 132 charts were available for review. Forty-three pediatric kidney recipients developed CD colitis. Their mean age was 3.2 yr; 74% (n = 37) of them developed their colitis during their initial hospital stay, with the mean timing of infection being 33 d. Forty-one (95%) had undergone intra-abdominal placement of the graft, with renal artery anastomoses to the aorta. Fifty adult kidney recipients developed CD colitis. Thirteen (26%) developed colitis during their initial hospital stay, with the mean timing of infection (for all adult kidney recipients) being 15 months. Thirty-nine kidney-pancreas recipients developed CD colitis. Mean timing of infection was 6 months. The overall incidence of CD colitis was 8%, with 16% in the pediatric kidney group, 15.5% in the kidney-pancreas group, and 3.5% in the adult kidney group. The difference in mean timing of infection was significant between the three groups (p < 0.001 for pediatric versus adult kidney recipients, p = 0.002 for pediatric kidney versus kidney-pancreas recipients, and p = 0.2846 for adult kidney versus kidney-pancreas recipients). CONCLUSION: The incidence of CD colitis is increased in pediatric kidney and kidney-pancreas recipients. Young recipient age ( < 5 yr), female gender, treatment of rejection with monoclonal antibodies, antibiotic use, and intra-abdominal graft placement have been shown to increase the incidence of this disease. Further studies concerning prevention in the high-risk groups are needed.

Adolescent↗
PubMed1998

Timing of colonic necrosis in hemolytic uremic syndrome.

Hemolytic uremic syndrome (HUS) consists of an acute onset of microangiopathic hemolytic anemia, thrombocytopenia, and renal dysfunction. HUS-associated colitis can be seen in up to 100% of patients and is usually associated with severe abdominal pain and distention. Colonic perforation is a complication of HUS that has a reported incidence of 1%-2%, and although there are several case reports in the literature describing perforation of the colon, it is still very difficult to discern the abdominal symptoms associated with HUS colitis from perforation. Four cases of colonic perforation are reported here from a consecutive series of 57 patients, in which a trend in the length of time from the onset of symptoms of HUS to colonic perforation was determined. A review of the literature for cases of HUS-associated colonic perforation was also performed. The time from the onset of HUS symptoms to colonic perforation in our series was similar to that found in the literature review (11 +/- 5 vs 14 +/- 8 days). Awareness that this complication has a tendency to occur towards the end of the 2nd week during the course of HUS is essential to avoid an unnecessary and untimely surgical intervention.

Adolescent↗
PubMed1997

Risk factors for kidney damage in the adult population of Wadena, Minnesota. A prospective study.

An increased albumin excretion rate (AER) is associated with impaired glucose tolerance and diabetes mellitus in some populations, but data on Americans of Northern European origin are lacking. In 1986-1987, AER and creatinine clearance were measured in 455 adults in a survey of the population of Wadena, Minnesota. Thirty-five subjects (8%) had an AER > or = 15 micrograms/minute, and eight of these had overt proteinuria (AER > or = 175 micrograms/minute). AER and creatinine clearance were uncorrelated except when AER was increased. Unadjusted mean AER in a stratified random sample of adults (n = 374) was 3.6 micrograms/minute. Adjusted values for 277 subjects with normal glucose tolerance and for 80 subjects with impaired glucose tolerance were very similar (3.8 and 3.7 micrograms/minute, respectively), whereas mean AER was 5.4 micrograms/minute for persons with non-insulin-dependent diabetes mellitus (NIDDM) who were not taking insulin and 9.4 micrograms/minute for persons with NIDDM who were taking insulin (p < 0.0001). After adjustment for age, mean creatinine clearance was unrelated to glucose tolerance. Systolic blood pressure was a major determinant of increased AER (p < 0.0001) and lowered creatinine clearance (p = 0.0011), independently of diabetes. AER was stable over 5 years among the 321 cases who were not taking insulin and were not severely hypertensive. The decrease in creatinine clearance was greater in ex-smokers and current smokers than in nonsmokers. The authors conclude that hypertension and NIDDM were independently associated with the risk of kidney damage in this population, as indicated by a higher AER. High-normal blood pressure, but not impaired glucose tolerance, was associated with microalbuminuria. These relatively mild changes may reflect an ethnically based resistance to the damaging effects of hyperglycemia on the kidney. Smoking may accelerate the aging-related decline in glomerular filtration rate.

Adult↗
PubMed1995

Renal transplantation and chronic dialysis in children and adolescents: the 1993 annual report of the North American Pediatric Renal Transplant Cooperative Study.

The 1993 North American Pediatric Renal Transplant Cooperative Study annual report summarizes data voluntarily contributed by 82 participating centers on 3,223 pediatric patients who received 2,819 renal transplants from January 1987 through January 1993 and 999 independent courses of dialysis from January 1992 through January 1993. In addition to updating information regarding trends and outcomes in pediatric renal transplantation presented in previous annual reports, 1st-year registry data are presented regarding current practices and trends in chronic dialysis therapy for children and adolescents in North America. Living donor graft (LDG) survival rate was 90% at 1 year, 85% at 2 years and 75% at 5 years post transplant. Cadaver graft (CG) survival rates were 76%, 71% and 62% at 1, 2 and 5 years post transplant, respectively. Overall mortality post transplantation continues to be low (CG 6.8%, LDG 4%), mortality remains high in young infants. The dialysis cohort was generally younger than the transplantation cohort. In all age groups, peritoneal dialysis was utilized in the majority of pediatric patients and the overall incidence of peritonitis was 1 episode per 8.2 patients months. External percutaneous catheters were utilized as the predominant chronic hemodialysis access in the study, and access site infections ranged from 6.9% at 1 month to 13.5% at 6 months.

Adolescent↗
PubMed1995

Correlation of donor antigen-specific hyporeactivity with allogeneic microchimerism in kidney and lung recipients.

Our previous studies indicate donor antigen-specific hyporeactivity is a useful marker for identifying solid organ transplant recipients at low risk for immunological complications; the hyporeactive subgroup experiences a lower incidence of chronic rejection. One purpose of the current study was to determine whether hyporeactivity could be identified in pediatric kidney recipients and whether it correlated with improved graft outcome. Of 18 pediatric kidney recipients tested, 6 (33%) had developed donor antigen-specific hyporeactivity. All 18 experienced good graft outcome. Second, we determined whether donor antigen-specific hyporeactivity correlates with peripheral blood microchimerism and outcome in adult kidney recipients. Our previous studies of lung recipients demonstrated development of obliterative bronchiolitis in recipients with microchimerism who remain responsive, but not in recipients who had become hyporesponsive to donor antigen. Preliminary results in our current study of 23 adult kidney recipients indicate microchimerism for 6 (26%): 4 hyporesponsive and 2 responsive to donor antigen. Microchimerism was not detected for 17 recipients: 6 hyporesponsive and 11 responsive to donor antigen. One hyporesponsive/chimeric patient and 4 recipients negative for both parameters have been diagnosed with biopsy-proven chronic rejection. In summary, both hyporeactivity and chimerism are found at a higher frequency in lung than kidney recipients. Unlike lung recipients, not all hyporesponsive kidney recipients had peripheral blood chimerism. Additional numbers are needed to determine if microchimerism correlates with donor antigen-specific hyporeactivity or graft outcome.

Adult↗
PubMed1993

Renal transplantation for infantile cystinosis: long-term follow-up.

Renal transplantation for infantile cystinosis corrects renal failure and prolongs survival. However, after transplantation, the disease may develop in the allograft and continue to progress in nonrenal organs. We studied seven children (6 boys, 1 girl) with infantile cystinosis who received 11 renal transplants (3 cadaver, 8 living-related) between May 1969 and December 1986. The age at transplant ranged from 6 to 12 years (mean, 9.1 years). Four children received second renal transplants at a mean age of 17 years (range, 16 to 22 years). The mean period of follow-up was 138 +/- 47 months. Three children received cysteamine therapy prior to transplantation. Nonrenal complications of infantile cystinosis present before transplantation were photophobia (n = 3), corneal crystals (n = 5), hypothyroidism (n = 1), rickets (n = 6), and short stature (n = 7). Graft and patient survival did not differ from controls matched for the time of transplantation. Two patients died (1 pneumococcal sepsis, 1 respiratory failure due to pulmonary fibrosis) with functioning grafts 5 and 14 years posttransplant. Complications that developed posttransplant included photophobia (n = 1), corneal crystals (n = 2), hypothyroidism (n = 4), polyneuropathy (n = 1), pulmonary fibrosis (n = 1), abnormal electroencephalogram without clinical seizures (n = 1), bladder stones (n = 1), and diabetes mellitus (n = 2). One patient received a corneal transplant. All seven children failed to show improvement in growth following transplantation. Cystine crystals are present in graft-infiltrating cells, but do not seem to affect kidney allograft function.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1992

Pediatric renal transplants--results with sequential immunosuppression.

Cyclosporine has improved the results of renal transplantation. In 1984, we began using it as part of a sequential immunosuppression protocol (MALG, AZA, P, and delayed administration of CsA) in our pediatric renal transplant recipients. We studied the outcome of the 131 pediatric renal transplants (less than or equal to 18 years of age at transplant) performed at our institution between June 1984 and March 1991. We compared these results with the 144 similar transplants performed since January 1980 that did not involve CsA immunosuppression. In the sequential immunosuppression group, there were 97 primary (74%) (26 [27%] cadaver, 71 [73%] living donor [LD]) and 34 (26%) retransplant (23 [68%] CAD, 11 [32%]) recipients. Age at transplant (mean +/- SD) was 7.4 +/- 5.5. Overall, 1-year actuarial graft survival was 93%; 1-year patient survival was 100%. The mean number of hospital readmissions was 3.0 +/- 3.5; 26 (20%) were readmission-free. The mean number of rejection episodes was .87 +/- 1.3 per patient; 73 (56%) were rejection-free. Importantly, LD (vs. CAD) recipients had fewer rejection episodes (P = 0.06). In the first post-transplant year, the serum creatinine level was significantly lower in primary (vs. retransplant) recipients and in LD (vs. CAD) recipients (P less than 0.05). In the 144 patients not receiving CsA, there were 129 (90%) primary (27 CAD, 102 LD) and 15 (10%) retransplant (7 CAD, 8 LD) recipients. Age at transplant was 6.9 +/- 5.3 years. The 1-year actuarial graft survival rate was 82%; the 1-year patient survival rate was 94%. The mean number of hospital readmissions was 3.3 +/- 2.3; 5 (8%) were readmission-free. The mean number of rejection episodes was 1.2 +/- 1.5; 27 (45%) were rejection-free. There was no difference in the serum creatinine level based on donor source or transplant number. Sequential immunosuppression has significantly improved patient (P = 0.003) and graft survival (P = 0.004) rates. Comparing sequential vs. non-CsA immunosuppression, there was no difference in the number of readmissions (P = 0.47), number of rejection episodes (P = 0.17), or serum creatinine level. The number of rejection-free patients was significantly lower in LD (vs. CAD) recipients (P less than 0.05). There was no evidence of progressive deterioration in renal function in the sequential (vs. non-CsA) recipients.

Adolescent↗
PubMed1992

Recurrence of disease in patients retransplanted for focal segmental glomerulosclerosis.

The natural history of focal segmental glomerulosclerosis in patients retransplanted after loss of a primary allograft is not well established. We studied 14 patients with FSGS who were retransplanted between April 1964 and September 1990 to determine if recurrence in a second or subsequent allograft could be predicted. In this group, 8 of the primary allografts were lost to recurrent disease and 6 to rejection. None of the 6 patients who lost their primary allograft to rejection without evidence of recurrent FSGS suffered recurrent disease after retransplantation. In contrast, 3 of the 8 patients who lost their primary allograft rapidly to FSGS suffered recurrent disease and loss of function in all subsequent allografts. The remaining 5 patients had prolonged function of the primary allograft ranging between 4 and 10.5 years, despite recurrence of FSGS. Of these 5 patients, 2 have excellent renal function after retransplantation without recurrence of FSGS in the secondary allograft at 9 and 10.5 years posttransplant; 2 have lost their secondary allograft to recurrent FSGS, but are free of recurrence in the third allograft at 0.5 and 5.8 years postoperatively; 1 maintains a serum creatinine level of 1.9 mg% despite recurrence of FSGS in the secondary allograft at 1 year postoperatively. Our data show that, without recurrence of FSGS in the primary allograft, further renal transplants will be free of recurrent disease. Based on this finding, we advocate use of living-related donors for second transplants in these patients. With rapid recurrence of FSGS and subsequent accelerated loss of the primary allograft, further renal transplants carry a high likelihood of recurrent FSGS and graft loss. A substantial proportion of patients with recurrent FSGS in the primary allograft will have prolonged renal function, and are likely to have excellent results with subsequent allografts.

Adolescent↗
PubMed1992

Renal transplantation in the first year of life: the treatment of choice for infants with end-stage renal disease.

The treatment of choice for end-stage renal failure within the first year of life is controversial. Between September 1970 and February 1991, we performed 28 kidney transplants (27 primary, 1 retransplant, 23 living donor, 5 cadaver) in infants less than 1 yr of age (mean, 7 +/- 2 months; range, 6 wk to 12 months). The 1-yr patient survival rate for living donor recipients was 100% versus 20% for cadaver recipients (P = 0.0001). The 1-yr graft survival rate for living donor recipients was 96% versus 20% for cadaver recipients (P = 0.001). The 1-yr patient survival rate for cyclosporin A (CSA) recipients (N = 12) was 100% versus 75% for non-CSA recipients (P = 0.03). The 1-yr graft survival rate for CSA recipients was 92% versus 75% for non-CSA recipients (P = 0.08). There was no difference in the number of rejection episodes or serum creatinine levels in CSA versus non-CSA recipients. Compared with pretransplant values, the mean posttransplant standard deviation scores (SDS) for height (N = 18), weight (N = 22), and head circumference (N = 8) improved: height SDS from -1.9 to -1.5 (not significant); weight SDS from -2.5 to 0.6 (P less than 0.0005); head circumference SDS from -2.0 to -0.7 (P = 0.01). Because no other renal replacement therapy can match these results, we conclude that renal transplantation is the treatment of choice for infants with end-stage renal failure.

Evaluation Studies as Topic↗
PubMed1991

Long-term quality of life after kidney transplantation in childhood.

Transplantation is the treatment of choice for children with end-stage renal disease. However, the long-term quality of life and socioprofessional outcome for those with successful transplants have not previously been reported. We studied these factors in patients transplanted when less than 18 years old who currently have greater than or equal to 10 years of graft function. A total of 57 questionnaires were sent out; 57 (100%) responded [24 female and 33 male patients; average (+/- SD) age at tx = 10 +/- 5 years (0.9-17.7); average f/u = 15.6 +/- 3 years (10-26); current age = 26 +/- 5 years (12-38); 26 had greater than 1 transplant]. Of the 57 respondents, 9 are less than 18 (all are in school); 48 are greater than or equal to 18 (7 in school, 37 employed, 4 unemployed); 12 are married, 1 engaged, and 2 divorced; and 9 have children. While in school, 43 (75%) had participated in sports, 37 (65%) in other extracurricular activities; 7 (12%) were A and 33 (58%) B students; 15 (26%) received awards or scholarships. For those working, the range of occupations is broad (average work week = 41 +/- 5 hr). Health-related absence from work has been nonexistent for 93%. Health is rated as good to excellent by 91% and fair by 9%. The future is regarded as hopeful or promising by 80%. Similarly, 89% are satisfied with life in general; 95% said health never or seldom interferes with family life; 95% feel health and drug side effects are of no or minor concern in sexual relationships. Only 3% feel health is a problem in maintaining a sexual relationship (41% are not sexually active). Only 4% stated that health often interferes with social life; 98% meet with friends on a regular basis; 76% are satisfied with personal relationships and 8% dissatisfied; 91% are satisfied with their ability to perform at work or school and 5% dissatisfied. Of note, 32% are dissatisfied with body appearance. Major concerns are short stature and brittle bones. Major suggestions include education/support groups to deal with teasing at school and peer problems. We conclude that transplanted children with long-term graft function have a favorable social and professional outcome. Overall, quality of life seems excellent.

Adolescent↗