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Biomedical subjects

Jodi M Smith

Publications and source records attributed to Jodi M Smith.

13 recordsLinked to original sources
PubMed2006

Sonic tooth brushing reduces gingival overgrowth in renal transplant recipients.

Cyclosporine (CSA) is a commonly used immunosuppressive medication in pediatric transplantation. Drug-induced gingival overgrowth (DIGO) is a frequent side effect associated with CSA use and can impair the patient's ability to achieve good oral hygiene. This study tested the hypothesis that sonic tooth brushing and oral hygiene instruction can reduce the occurrence or severity of DIGO in CSA-treated pediatric renal transplant recipients. Twenty-three pediatric renal transplant patients with DIGO were randomly allocated to treatment or control groups. The treatment group received oral hygiene instruction and use of a sonic toothbrush, while the control group continued their usual home care with manual brushes. Dental impressions and photographs of all subjects were taken at baseline and every 3 months for a year. The casts and photographs were evaluated by a dental panel to compare the DIGO levels from baseline until the end of the study. After 12 months the control group had significantly more severe DIGO than did the sonic tooth brushing and oral hygiene instruction group (OR=4.5, 95%CI=1.2-16.0, P=0.03). Of the risk factors considered, only male gender was significantly associated with worse outcome (OR=6.1, 95%CI=2.3-16.1, P=0.03). The use of a powered toothbrush, together with oral hygiene instruction, may be an important component of health maintenance for pediatric transplant patients on CSA.

Adolescent↗
PubMed2006

Risk of lymphoma after renal transplantation varies with time: an analysis of the United States Renal Data System.

BACKGROUND: Characterization of the incidence of posttransplant lymphoma over time may help guide the timing and intensity of posttransplant monitoring. We analyzed the United States Renal Data System to describe the occurrence of lymphoma following renal transplantation. METHODS: All end-stage renal disease patients placed on the transplant waiting list between January 1, 1990 and December 31, 1999 were considered. Survival analysis was used to estimate lymphoma risk in renal transplant patients. RESULTS: Of 89,260 eligible patients, a total of 556 lymphoma cases were identified with 357 in transplant patients. The overall rate of posttransplant lymphoma was 33.3/10,000 person-years in transplant patients. There was variation in the duration and magnitude of increased lymphoma risk by age. The highest rates of lymphoma were among transplanted patients in the first 12 months, after which the rate of lymphoma decreased. Among Caucasian transplant recipients less than 25 years of age, the adjusted relative risk of lymphoma ranged from 13.82 [95% CI: (3.96, 48.15)] within 6 months posttransplant to 3.46 [95% CI: (0.69, 17.44)] within months 30-36 posttransplant. Only patients under 25 years had a notably increased risk beyond the first 2 posttransplant years. The risk of lymphoma differed by race, with Caucasian patients at nearly double the risk of African-Americans. Gender was not associated with lymphoma incidence. CONCLUSIONS: We found and quantified a time-varying relationship between renal transplant and lymphoma risk. This information can be used in combination with knowledge of established risk factors to guide the schedule of posttransplant monitoring.

Adult↗
PubMed2006

Emerging viral infections in transplantation.

Viral infections are an important complication of transplantation. The introduction of more potent immunosuppressive agents over the past decade correlates with an increase in the rate of hospitalizations of transplant patients with infections. Specifically, viral infections have emerged as a major source of morbidity and mortality in transplantation. There are several potential intervention strategies in the face of emerging infections and it is likely that the approach will differ depending on the virus in question. These include viral surveillance and pre-emptive therapy, intervention of the transplant community, and policy change at the level of government, blood bank and organ procurement organizations. This review focuses on the emergence of the herpesviruses; HHV-6 and HHV-7. In addition, the issue of virus transmission through organ transplant is addressed with a discussion of West Nile virus and the rabies virus.

Antiviral Agents↗
PubMed2005

Renal transplantation in adolescents.

Renal transplantation remains the goal for the pediatric patient with end-stage renal disease. Recent advances in technology and immunosuppression have greatly enhanced patient and graft survival, while reducing significant complications. However, transplantation of adolescents is still fraught with the potential for serious problems. The increased risk of graft loss, late acute rejection, and incomplete rejection reversal observed in the adolescent age group demands further investigation. Lack of adherence to immunosuppression regimens may be an important contributory factor. Strategies to address the unique concerns of this high-risk population, including the use of a multidisciplinary team, are essential to improving outcomes.

Adolescent↗
PubMed2005

Childhood asthma hospitalization risk after cesarean delivery in former term and premature infants.

BACKGROUND: Cesarean delivery modifies infant gut bacterial flora composition, which may result in hindered tolerance to allergenic substances, thereby increasing the risk of asthma in accordance with the hygiene hypothesis. Results of previous studies regarding an association between birth route and asthma are conflicting, and these studies have not evaluated some potential confounding effects, including prematurity and maternal asthma. OBJECTIVE: To determine whether cesarean delivery in full-term and premature infants increases the risk of subsequent childhood asthma hospitalization. METHODS: We conducted a case-control study using the Washington State Birth Events Record Database linked to statewide hospitalization data. The study included 2,028 children hospitalized for asthma (cases) and 8,292 age-matched controls. RESULTS: Cesarean delivery was modestly associated with an increased risk of asthma hospitalization (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.04-1.39). However, when analyzed separately, there was an association between cesarean delivery and asthma hospitalization in premature infants (OR, 1.90; 95% CI, 1.09-3.02) but not in full-term infants (OR, 1.15; 95% CI, 0.97-1.34). CONCLUSIONS: Cesarean delivery was associated with subsequent asthma hospitalization only in premature infants. Because mothers with asthma are reported to have increased rates of cesarean delivery and premature delivery, other factors in addition to the hygiene hypothesis, including genetic and in utero influences associated with maternal asthma, may contribute to the increased risk of asthma in premature infants.

Adult↗
PubMed2004

Polyomavirus nephropathy in pediatric kidney transplant recipients.

Given the limited information regarding BK virus-associated nephropathy (BKVN) in pediatric kidney transplant recipients, we assessed the incidence, risk factors, clinical and virologic features of BKVN in pediatric renal transplant recipients at a single transplant center by means of a retrospective cohort study. Histologically confirmed BKVN developed in 6 of 173 (3.5%) kidney transplant recipients at a median of 15 months post-transplant (range: 4-47 months). At a median follow-up of 28 months (range: 5-32), all patients had functioning grafts with mean creatinine and GFR of 1.9 mg/dL and 58 mL/min/1.73 m2, respectively. At the time of diagnosis, all cases had viruria (median 6.1 x 10(6) copies/mL, range: 10(5) to 3.9 x 10(8) copies/mL) and viremia (median 21,000 copies/mL, range: 10,000-40,000 copies/mL). Recipient seronegativity for BKV was significantly associated with the development of BKVN (p = 0.01). BKVN is an important cause of late allograft dysfunction and is strongly associated with recipient seronegativity in pediatric kidney transplant recipients. Further studies to confirm this finding and to define the clinical utility of routine pre-transplant BKV serologic testing are warranted.

Adolescent↗
PubMed2003

Current immunosuppressive agents: efficacy, side effects, and utilization.

Advances in immunosuppressive therapy over the past decade have led to dramatic improvements in graft survival. With the development of new agents, the focus of the transplant community is to establish regimens that maintain excellent graft survival rates but with fewer toxicities including infection, nephrotoxicity, malignancy, and cosmetic effects. Examples include the use of steroid-free protocols and calcineurin avoidance regimens, which are currently being studied by NAPRTCS. The ultimate goal of transplant immunosuppressive therapy is the induction of tolerance. As we learn more about immune function from basic and clinical research, tolerance to allografts seems a more reachable goal.

Abatacept↗
PubMed2003

Pretransplant peritoneal dialysis and graft thrombosis following pediatric kidney transplantation: a NAPRTCS report.

Graft thrombosis is a common cause of graft failure in pediatric renal transplantation. Several previous studies, including a North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) review of pretransplant dialysis status and graft outcomes, have described a potential correlation of peritoneal dialysis (PD) and graft thrombosis. This issue is of particular concern for pediatric transplant programs as more than 65% of children with end stage renal disease are treated with PD. We reviewed 7247 pediatric renal transplants performed between 1987 and 2001. Thrombosis was the cause of graft loss in 2.7% (199) of all the transplants performed. Among failed transplants, thrombosis was the third most common cause of graft loss in both index (11.6%) and subsequent transplants (14.5%). Thrombosis becomes the most common cause of graft failure (21%, 61/294) if one looks at transplants in the later cohort, from 1996 to 2001. This change is primarily because of a decrease in the incidence of acute rejection. In the PD group, 3.4% of all grafts were lost as a result of thrombosis. This compares with 1.9% in the hemodialysis group, 2.4% in the pre-emptive transplant group, and 4.1% among patients who received both dialysis modalities. There was a statistically significant difference in thrombosis failure risk in the different dialysis groups (p = 0.005) with those who received only peritoneal dialysis having the highest risk. Additional significant risk factors for graft thrombosis included; cadaver donor source (p < 0.001), cold ischemia time >24 h (p < 0.001), history of prior transplant (p < 0.001), donor age <6 yr (p < 0.001), and >5 pretransplant blood transfusions (p = 0.02). Using stepwise proportional hazards modeling, only pretransplant peritoneal dialysis, >24 h cold ischemia time, prior transplant, and donor age <6 yr were simultaneously associated with an increased risk of thrombosis. We conclude that pretransplant PD is associated with an increased risk of graft thrombosis. Special precautions should be undertaken in pediatric renal transplant patients who have received PD, especially infants and young children.

Child↗
PubMed2002

Platelet-activating factor and Escherichia coliO157:H7 infections.

The role of platelet-activating factor (PAF), a phospholipid inflammatory mediator, in Escherichia coli O157:H7-associated hemolytic uremic syndrome (HUS) is unknown. PAF is synthesized by diverse cells and is degraded by PAF-acetylhydrolase (PAF-AH). Deficient PAF-AH activity results from a G-->T transversion at position 994 of exon 9. We examined children infected with E. coliO157:H7 to determine if PAF levels or the PAF-AH ( G994T) mutation reflects the risk of developing HUS. Plasma PAF concentrations were determined using chloroform/methanol extraction, thin layer chromatography purification, and scintillation proximity assay in 10 patients with uncomplicated infection (UI), 10 infected patients who subsequently developed HUS (pre-HUS), 5 HUS patients, and 8 healthy controls. The PAF-AH ( G994T) allele frequency was determined in 52 UI children, 15 with HUS, and 11 controls. Wilcoxon rank sum tests were performed to test differences in location (median) of pairs of groups. PAF levels were higher in the UI ( P=0.04) and pre-HUS ( P=0.01) groups than in healthy controls. No subject had the PAF-AH ( G994T) allele. Thus, elevated plasma PAF levels occur in E. coliO157:H7-infected children, even without HUS, but diminish when HUS develops. The PAF-AH ( G994T) allele does not contribute to the risk of developing HUS.

Blood Cell Count↗
PubMed2002

Abl: mechanisms of regulation and activation.

The Abl non-receptor tyrosine kinase has been implicated in a wide variety of cellular processes, yet its function and regulation remain poorly understood. Abl has resisted complete understanding not due to lack of interest, but due to the complexity of its overall structure and the corresponding complexity and diversity of its biological activities in the cell. Although Abl consists of many familiar modules with well-understood activities, the ways in which these modules interact are manifold and defy simple categorization. A picture now emerges in which Abl can be potentially regulated in many ways: by phosphorylation, by intramolecular interaction, by interaction with a variety of other proteins, by subcellular localization. Far from being a simple on-off switch, it appears that Abl is better understood as existing in a complex and dynamic equilibrium of states, an equilibrium that can be affected by many signaling inputs. In this review we will discuss the various ways in which the kinase activity of Abl can be regulated; other recent reviews have discussed the larger issue of possible biological roles of Abl (1-3).

Animals↗
PubMed2002

Renal transplant outcomes in adolescents: a report of the North American Pediatric Renal Transplant Cooperative Study.

Recipient age at transplant is an important predictor of outcome. The age most commonly associated with increased risk is infancy. An important, but less recognized, age group at high risk is the adolescent. We analyzed the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database to determine the patient and graft outcomes of adolescents (13-17 yr of age) compared with younger children. The adolescent age group had a similar percentage patient survival rate compared to that of the younger age groups, except for the infants (0-1 yr), who had a dramatic drop-off in the early post-transplant period. Regarding the long-term graft survival for living donor recipients, adolescents had the poorest percentage graft survival compared to the other age groups, including the infants (p < 0.001). Among cadaver donor recipients, the adolescent group had a significantly poorer graft survival than the 2-5 yr and 6-12 yr age groups (p < 0.001). Although the infants had the poorest graft survival (p < 0.001), after the sharp drop-off in the immediate post-transplant period the slope of their graft-survival curve was similar to that of the 13-17 yr age group. The percentage of late acute rejection episodes among the 6-12 yr (26.0%) and 13-17 yr (22.2%) age groups was significantly higher than in the younger age groups (p < 0.001). The adolescents had relatively poor rejection reversal outcomes compared to the other age groups, with fewer complete rejection reversals and a greater number of partial reversals (p < 0.001). The increased risk of graft loss, late acute rejection, and incomplete rejection reversal observed in the adolescent age group demands further investigation. Lack of compliance with immunosuppression regimens may be an important contributory factor. Strategies to address the unique concerns of this high-risk population will be essential to improve outcomes.

Adolescent↗