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Biomedical subjects

Janine Janosky

Publications and source records attributed to Janine Janosky.

At least 19 recordsLinked to original sources

The role of education in biostatistical consulting.

Medical students, residents, postdoctoral fellows, and faculty commonly consult with biostatistical experts about study design and data analysis when conducting clinical research. The role of biostatistical training during these consultations is examined, and characterizations of the connections between biostatistical consultation and education are reviewed. The presence and kinds of teaching efforts during biostatistical consults at four academic research institutions over various periods of time between 1999 and 2005 (237 consultations in total) were recorded and are described. By site, 67, 70, 78, and 100 per cent of the consulting sessions included biostatistical training, with an overall 78 per cent (95 per cent CI: 73-83 per cent) of consultations including an educational component when all consultations were combined. Training covered a wide range of biostatistical topics. Seventy-five per cent of the consultations with faculty (120/161), 79 per cent with fellows and residents (31/39), and 100 per cent with medical students (10/10) included some degree of instruction in study design or statistical analysis topics. Results show that both the need and the opportunity exist for specialized biostatistical instruction during one-on-one sessions between a consulting biostatistician and physicians, medical students, and research staff. Academic researchers are ideally positioned to absorb this kind of training when they initiate a request for assistance with their own research project.

Biometry↗

Persistent donor-specific alloreactivity may portend delayed liver rejection during drug minimization in children.

Immunoreactivity, immunosuppression requirement and liver graft function was assessed serially for its relationship to delayed/recurrent acute cellular rejection (ACR) after the first 60 days in 36 pediatric primary liver transplant (LTx) recipients. Subjects were classified as rejectors (n=20) or Non-Rejectors (n=16) based on the presence/absence of biopsy-proven ACR in the first 60 days. All children received anti-lymphocyte induction and steroid-free Tacrolimus or Sirolimus monotherapy, as reported previously. Median age was 4 years (0.45-18) and follow-up was 570 days (106-1144). Compared with non-rejectors, rejectors 1. took significantly longer to achieve reduced donor-specific alloreactivity by MLR (p=0.049), and "low" TAC/SRL whole blood requirements defined as TAC levels < or = 8 ng/ml (p=0.0048), 2. experienced significantly greater variation in time to achieve reduced donor-specific immunoreactivity (SEM 0.8 vs 3.85, p=0.0048), and 3. experienced greater ACR incidence during minimization of immunosuppression (35% versus 6%, p=0.032). Serial monitoring of immunoreactivity may increase the safety with which immunosuppression is minimized in pediatric LTx.

Adolescent↗

Longitudinal study of physiologic insulin resistance and metabolic changes of puberty.

Cross-sectional studies have shown that 1) adolescents are insulin resistant compared with prepubertal children and adults, 2) pubertal insulin resistance is likely mediated by growth hormone (GH), and 3) pubertal insulin resistance is associated with increased fat oxidation and decreased glucose oxidation. The aim of this study was to assess the validity of these cross-sectional observations by performing a longitudinal study in normal children during the prepubertal and pubertal periods. Nine healthy, normal weight, prepubertal children underwent hyperinsulinemic-euglycemic and hyperglycemic clamp studies for evaluation of insulin sensitivity and insulin secretion. Children had repeat evaluations during puberty. Consistent with cross-sectional observations, this longitudinal study demonstrated that during puberty: 1) insulin sensitivity decreased by approximately 50%, 2) the decrease in insulin sensitivity was compensated by a doubling in insulin secretion, and 3) the decrease in insulin sensitivity was independent of changes in percentage of body fat. Puberty was associated with increased total body lipolysis and decreased glucose oxidation. A novel observation is the demonstration of approximately 50% decrease in adiponectin levels at the pubertal time point. These metabolic changes are proposed to be partially mediated by increased GH secretion and are consistent with the Randle cycle of competition between glucose and fat oxidation.

Adiponectin↗

Individualizing combination of two antiproliferative immunosuppressants with pharmacodynamic modeling of stimulated lymphocyte responses.

BACKGROUND: Unpredictable serious adverse events (SAE) of immunosuppression, e.g. nephrotoxicity, with the nephrotoxic immunosuppressants have fostered interest in alternative regimens, which contain two antiproliferative agents, and individualized therapy. However, titration of such combinations to individual needs is not understood. SPECIFIC AIM: To determine concentration (C) mixtures of mycophenolate mofetil (MMF) and sirolimus (SRL), which produce half-maximal inhibitory effect (EC(50)) on human lymphocytes from individual subjects. METHODS: Concentration mixtures of MMF (0-5 mug/ml) and SRL (0-30 ng/ml) were incubated with whole blood from each of five healthy human subjects. The intracellular cytokines IL-2, TNF-alpha, and IFN-gamma were measured in PMA-ionomycin-stimulated T-cells (CD4+), while CD54, CD95, CD86, CD25, CD69, and CD71 were measured in pokeweed mitogen-stimulated B-cells, by flow cytometry. Pharmacodynamic (PD) relationships were evaluated using Hill equations modified for single and multidrug regimens, and expressed as EC(50) for each target receptor. RESULTS: No change was seen in the expression of the T-cell cytokines with either MMF or SRL. Each B-cell receptor was inhibited with increasing concentrations of either MMF or SRL. Each B-cell receptor was also inhibited half-maximally at lower concentrations of MMF in the presence of SRL, than with either agent alone, for the test population of five subjects together, and for each of five individual subjects. However, each subject showed distinctly different amounts of MMF and SRL that needed to be present together, in order to produce an identical inhibitory effect on lymphocyte function. CONCLUSIONS: PD analysis of biological effect can potentially predict optimal concentration mixtures of two immunosuppressants for individual recipients, and enhance rejection prophylaxis and safety. While this holds promise for drug development efforts, clinical application must await correlation of lymphocyte markers with post-transplant clinical outcomes.

Antigens, CD↗

Use of dexmedetomidine in children after cardiac and thoracic surgery.

OBJECTIVE: In this report, we describe our experience with the use of dexmedetomidine in spontaneously breathing as well as in mechanically ventilated patients, after congenital cardiac and thoracic surgery. DESIGN: Retrospective case series. SETTING: University hospital, pediatric cardiac intensive care unit. PATIENTS: Thirty-three spontaneously breathing and five mechanically ventilated patients who received dexmedetomidine after cardiothoracic surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirty-eight patients, age 8 +/- 1.1 yrs old and weight 29 +/- 3.8 kg, were included. Seven patients (18%) were <1 yr old. Dexmedetomidine was used as a primary sedative and analgesic agent, and when its effect was considered inadequate, despite incremental infusion doses, a rescue agent was administered. The initial dexmedetomidine infusion dose was 0.32 +/- 0.15 microg/kg/hr followed by an average infusion of 0.3 +/- 0.05 microg/kg/hr (range 0.1-0.75 microg/kg/hr). There was a trend toward higher dexmedetomidine infusion requirement in patients <1 yr old compared with older children, 0.4 +/- 0.13 vs. 0.29 +/- 0.17 microg/kg/hr (p = .06). Desired sedation and analgesia were achieved during 93% and 83% of the dexmedetomidine infusion, respectively. According to the intensive care unit sedation scale (score 0-3) and two pain scales (Numeric Visual Analog Scale and Face, Legs, Activity, Cry, and Consolability, score 0-10), the mean sedation score was 1.3 +/- 0.6 (mild sedation) and the mean pain score was 1.5 +/- 0.9 (mild pain). The most frequently rescue drugs administered were fentanyl, morphine, and midazolam. Overall, 49 rescue doses of sedatives/analgesics were given. Patients <1 yr old required more rescue boluses than older children, 22 boluses (3.19 +/- 0.8) vs. 27 boluses (0.8 +/- 0.2, p = .003). Throughout the dexmedetomidine infusion there was no significant change in the systolic and diastolic blood pressure trend. Six patients (15%) had documented hypotension. In three, hypotension resolved with decreasing the dexmedetomidine infusion dose whereas in the other three, hypotension resolved after discontinuing the infusion. Although there was a trend toward lower heart rates, this was not clinically significant. One patient had an episode of considerable bradycardia without hypotension, which resolved shortly after discontinuing the dexmedetomidine infusion. No significant changes in the arterial blood gases or respiratory rates were observed. There was no mortality, and the total intensive care unit length of stay was 19 +/- 2 hrs. CONCLUSIONS: Our data suggest that dexmedetomidine is a well-tolerated and effective agent for both spontaneously breathing and mechanically ventilated patients following congenital cardiac and thoracic surgery.

Adolescent↗

Use of markers of dyslipidemia to identify overweight youth with insulin resistance.

CONTEXT: Markers to identify overweight youth with insulin resistance are of clinical importance. OBJECTIVE: To determine if markers of dyslipidemia could identify overweight adolescents with insulin resistance. SETTING, PARTICIPANTS, AND STUDY DESIGN: We retrospectively examined the association between markers of dyslipidemia and insulin resistance in 35 overweight [body mass index (BMI) of > or =95th percentile], white adolescents [mean age 13.5 +/- (SD) 1.6 yr] who had participated in hyperinsulinemic-euglycemic clamp studies to evaluate insulin action. Total body fat was measured by dual-energy X-ray absorptiometry and abdominal fat with computed tomography. Using receiver-operating curves, cut-points for triglyceride (TG)/high-density lipoprotein (HDL) and TG level to identify overweight individuals in the lowest tertile for insulin sensitivity were determined. MAIN OUTCOME MEASURE: Difference in the values for insulin sensitivity among the groups. RESULTS: Of the markers examined (TG, TG/HDL, adiponectin, measures of adiposity and fasting insulin), fasting insulin was the strongest correlate of insulin sensitivity (r = 0.87, p < 0.001). Youth with TG/HDL level > or =3 had lower insulin sensitivity (50% lower median values, p < 0.01) and higher visceral fat (p < 0.05) despite BMI comparable to that of youth with TG/HDL level <3. Youth with TG/HDL > or =3 had a sensitivity of 61% and specificity of 82% for identifying participants with the greatest degree of insulin resistance. CONCLUSIONS: TG and TG/HDL are easily obtained markers associated with insulin resistance. Further research is needed to determine if a constellation of clinical findings, such as components of the metabolic syndrome along with other metabolic markers including adiponectin, better predicts insulin resistance in overweight youth.

Abdominal Fat↗

Influence of wet surfaces and fall height on pediatric injury risk in feet-first freefalls as predicted using a test dummy.

INTRODUCTION: Falls are a major cause of morbidity and mortality in children, but are also reported falsely in child abuse. Therefore, it is of interest to understand those factors which may lead to a higher likelihood of injury in a feet-first freefall. METHODS: We used laboratory freefall experiments and a 3-year-old Hybrid III anthropomorphic test dummy (ATD) to assess head and femur injury risk. Wet and dry linoleum impact surfaces were used from three fall heights: 22, 35 and 47 in. RESULTS: For a given fall height, dry surfaces were associated with higher head injury criteria (HIC) values than wet surfaces. Changes in fall height 22-47 in. did not significantly affect HIC values for falls onto either surface. Generally, compressive and bending femur loading increased significantly for wet as compared to dry linoleum. CONCLUSIONS: In simulated feet first freefall experiments up to 47 in. using a 3-year-old test dummy, a low risk of contact type head injury and femur fracture was found. However, both fall height and surface conditions influenced femur loading and head injury measures. Future efforts should explore the risk of head injury associated with angular acceleration in freefalls.

Acceleration↗

Observed versus reported precepting skills: teaching behaviours in a community ambulatory clerkship.

PURPOSE: Community-based doctors are increasingly utilised for the clinical education of medical students. Faculty development programmes are frequently provided. However, data about the community faculty-student teaching interaction and the longterm impact of such programmes are limited. This study observes community faculty-student teaching interactions and assesses the use of clinical teaching methods taught during faculty development workshops. METHODS: Between March and August 2002, 13 rural, urban and suburban community-based faculty who completed at least 1 faculty development workshop were observed during faculty-student-patient encounters and interviewed. Observer-interviewers utilised a checklist to record teaching styles, methods and skills, and administered a questionnaire to obtain community faculty's self-perceptions. RESULTS: On observation, the assertive precepting style and didactic teaching predominated in 90% and 86% of teaching encounters, respectively. Interactive discussion and direct observation occurred less often, in 71% and 18% of encounters, respectively. Feedback was provided in 25% of encounters. On interview, community faculty reported that faculty development workshops resulted in improved precepting effectiveness and professional satisfaction with moderate to considerable improvement in feedback, interactive teaching and use of multiple precepting styles for 100%, 77% and 77% of community faculty, respectively. Community faculty reported that their skills in addressing problem students, direct observation and didactic teaching improved moderately. There was little statistical correlation between self-assessed and observed skills. CONCLUSIONS: Community-based faculty rate their teaching skills as improved following faculty development. Observation reveals that interactive discussion, direct observation, feedback and problem management skills are still lacking.

Clinical Clerkship↗

Enhanced donor-specific alloreactivity occurs independently of immunosuppression in children with early liver rejection.

UNLABELLED: To determine whether early acute cellular rejection (ACR) is associated with sub-optimal immunosuppression in children with liver transplants (LTx). METHODS: Twenty-five children with primary LTx after pre-transplant rabbit anti-thymocyte globulin (rATG), and steroid-free tacrolimus (TAC) were evaluated. Mitogen-stimulated T- and B-cell responses and mixed lymphocyte response to donor and third-party antigens were performed at several time points between two consecutive TAC doses. TAC concentrations (C) associated with half-maximal effect (EC(50)) on lymphocytes was determined by pharmacodynamic equations. RESULTS: Mean age was 7.2 +/- 6.2 years, mean time to lymphocyte function studies was 25 +/- 19 days. Acute rejection occurred at a mean interval of 31 +/- 19 days after LTx. Rejectors (n = 16) demonstrated significantly higher EC(50) of TAC for the intra-cellular IFN-gamma in T cells (p = 0.005) and its CD8+ sub-population (p = 0.027) as well as the co-stimulatory/activation receptor CD54 on B cells (p = 0.0001). The response of recipient lymphocytes to donor antigen was significantly higher in rejectors, compared with non-rejectors (p = 0.015). The patient groups demonstrated no differences in third-party MLR, or in C of TAC. CONCLUSIONS: Independent of the amount of immunosuppressant, ACR of liver allografts in children is associated with enhanced donor-specific alloreactivity. This is accompanied by a cytotoxic T-cell sub-population with increased requirement for TAC.

Adolescent↗

Youth type 2 diabetes: insulin resistance, beta-cell failure, or both?

OBJECTIVE: This study evaluates insulin sensitivity, pancreatic beta-cell function (BCF), and the balance between the two in youth with type 2 diabetes and assesses the relationship of diabetes duration and HbA(1c) to insulin sensitivity and BCF. RESEARCH DESIGN AND METHODS: The subjects were 14 adolescents with type 2 diabetes and 20 obese control subjects of comparable age, BMI, body composition, and puberty. Insulin sensitivity was evaluated with a 3-h hyperinsulinemic (80 mU . m(-2) . min(-1)) euglycemic clamp. First-phase insulin secretion (FPIS) and second-phase insulin secretion (SPIS) were evaluated with a 2-h hyperglycemic (12.5 mmol/l) clamp. Fasting glucose rate of appearance was determined with the use of [6,6-(2)H(2)]glucose. RESULTS: Fasting glucose rate of appearance was higher in type 2 diabetic patients than in obese control subjects (16.5 +/- 1.1 vs. 12.3 +/- 0.5 micromol . kg(-1) . min(-1); P = 0.002). Insulin sensitivity was lower in type 2 diabetic patients than in obese control subjects (1.0 +/- 0.1 vs. 2.0 +/- 0.2 micromol . kg(-1) . min(-1) per pmol/l; P = 0.001). Fasting insulin was higher in type 2 diabetic patients than in obese control subjects (289.8 +/- 24.6 vs. 220.2 +/- 18.0 pmol/l; P = 0.007), and FPIS and SPIS were lower (FPIS: 357.6 +/- 42.0 vs. 1,365.0 +/- 111.0 pmol/l; SPIS: 652.2 +/- 88.8 vs. 1,376.4 +/- 88.8 pmol/l; P < 0.001 for both). The glucose disposition index (GDI = insulin sensitivity x FPIS) was approximately 86% lower in type 2 diabetic patients than in obese control subjects. HbA(1c) correlated with FPIS (r = -0.61, P = 0.025) with no relationship to insulin sensitivity. CONCLUSIONS: Despite the impairment in both insulin sensitivity and BCF in youth with type 2 diabetes, the magnitude of the derangement is greater in BCF than insulin sensitivity when compared with that in obese control subjects. The inverse relationship between BCF and HbA(1c) may either reflect the impact of deteriorating BCF on glycemic control or be a manifestation of a glucotoxic phenomenon on BCF. Future studies in youth type 2 diabetes should target the natural course of beta-cell failure and means of retarding and/or preventing it.

Adiponectin↗

Multiparametric effect: concentration analyses.

Immunosuppressant drug toxicity currently competes with acute rejection, as the major cause of efficacy failure of potent new agents in clinical transplantation. The development of mechanistic drug targets as surrogate endpoints for use in the clinic has been facilitated by fluorescent imaging techniques which measure multiple cytokines and cell surface receptors on stimulated (peripheral blood) lymphocyte responses. However, the promise of delivering customized drug therapy to the transplant recipient remains unfulfilled. In this brief review, computational algorithms that can relate multiparametric effects to clinical drug concentrations of immunosuppressants are discussed. Based on Hill equations, these pharmacodynamic modeling techniques have been used to simulate single-agent effects, combination regimen effects, as well as the individual response to combination regimens. The potential implications of these models crystallize the clinical challenges confronting practitioners of clinical, post-transplant immunosuppression.

Algorithms↗

Validation of surrogate estimates of insulin sensitivity and insulin secretion in children and adolescents.

OBJECTIVES: To compare insulin sensitivity and pancreatic beta-cell function measured by the euglycemic and the hyperglycemic clamp, with simple estimates of insulin sensitivity and pancreatic beta-cell function in youth. Study design We measured insulin sensitivity with a euglycemic clamp and first- and second-phase insulin secretion with a hyperglycemic clamp in 156 AA and white youths. Estimates of insulin sensitivity (fasting insulin level [I(F)], the ratio of fasting glucose [G(F)] to I(F) [G(F)/I(F)], homeostasis model assessment estimate of insulin sensitivity [HOMA IS], and quantitative insulin sensitivity check index [QUICKI]) and estimates of pancreatic beta-cell function (I(F), the ratio of I(F) to G(F) [I(F)/G(F)], and homeostasis model assessment estimate of pancreatic beta-cell function [HOMA %B]) were derived from fasting measurements. RESULTS: In the total group, IS(Eu) correlated strongly with I(F) (r=-0.92), G(F)/I(F) (r=0.92), HOMA IS (r=0.91), and QUICKI (r=0.91) (P<.01). First-phase and second-phase insulin secretion correlated with I(F), I(F)/G(F), and HOMA %B (first-phase insulin secretion: r=0.76, 0.79, 0.82; second-phase insulin secretion: r=0.83, 0.86, 0.86, respectively; P<.01). CONCLUSIONS: Simple estimates of insulin sensitivity and pancreatic beta-cell function using fasting insulin and glucose levels serve as surrogate measures of insulin sensitivity and secretion in nondiabetic youths. The validity of these conclusions in children with impaired glucose tolerance and type 2 diabetes mellitus remains to be determined.

Adolescent↗

Lymphocyte subsets may discern treatment effects in children and young adults with post-transplant lymphoproliferative disorder.

To identify potential alternatives to Epstein-Barr virus (EBV)-specific cytotoxic T-cell responses, peripheral lymphocyte subsets (PLS) (CD4+, CD8+, CD3+, CD19+, CD56+) were measured by flow cytometry in children with abdominal transplants (n = 22) and heart transplants (n = 2), with (n = 14) and without (n = 10, group C) post-transplant lymphoproliferative disorder (PTLD). PTLD resolved with reduced immunosuppression and antiviral therapy in eight children (group B). Recalcitrant PTLD was observed in six children (group A). Recalcitrant PTLD followed prior antilymphocyte therapy [monoclonal anti-CD3 antibody (OKT3) and thymoglobin (n = 3) and thymoglobin (n = 1)] for refractory rejection in four of these six children, and resolved after treatment with rituximab (anti-CD20 monoclonal antibody). Ten children without PTLD served as a control group (group C). Between group comparisons showed a numeric increase in CD8 + cells and significantly lower CD4:CD8 ratios in both PTLD groups (A and B) compared with group C. Group A children also demonstrated significant depletion of natural killer (NK) cells, and post-rituximab depletion of B-cells compared with group B (no rituximab treatment). We conclude that NK cell depletion with a reversed CD4:CD8 ratio may represent a persistent immunosuppressed state, which may result from prior antilymphocyte therapy and may predispose to recalcitrant EBV-PTLD. Clinical remission with rituximab is accompanied by B-cell depletion. Serial monitoring of PLS from the time of diagnosis of PTLD will be necessary to confirm these observations.

Adolescent↗

Parent-reported language skills in relation to otitis media during the first 3 years of life.

As part of a larger study of the potential impact of early-life otitis media (OM) on speech, language, cognition, and behavior, we studied the degree of association between parent-reported language scores at ages 1, 2, and 3 years and the cumulative duration of middle-ear effusion (MEE) during the first 3 years of life in a demographically diverse sample of 621 children. We estimated the cumulative percentage of days with MEE from prospective monthly observations of middle-ear status and interpolations for periods between visits. For each child, parents completed the appropriate inventory of the MacArthur Communicative Development Inventories (CDI; L. Fenson et al., 1993) at ages 1, 2, and 3 years. We also evaluated the contribution of maternal education, as a proxy for socioeconomic status, to scores on the parent reports. Scores on the new CDI-III (B. Oliver et al., in press) varied positively with sociodemographic variables and were significantly correlated with scores from the CDI used when the children were younger. Unadjusted correlations between scores at ages 1 and 2 years and the percentages of days with MEE in the respective antecedent periods were statistically nonsignificant or of questionable clinical importance. The correlations between parent-reported scores at age 3 years and children's cumulative percentage of days with MEE in Years 1, 2, and 3 combined ranged from -.187 to -.248 (all p values < .001). The percentage of days with MEE and maternal education each contributed independently to scores at age 3 years. In the light of other findings from the larger study, we think it likely that the negative associations between language measures and MEE reflect confounding factors that contribute, on the one hand, to the duration of OM in young children and, on the other hand, to slow development of their language skills.

Audiometry↗

Obesity, regional fat distribution, and syndrome X in obese black versus white adolescents: race differential in diabetogenic and atherogenic risk factors.

The incidence of type 2 diabetes mellitus in children is increasing with the increasing prevalence of obesity, particularly in African-American children. We hypothesized that African-American obese adolescents are more insulin resistant than their white peers, but have lower insulin secretion, thus increasing their risk of type 2 diabetes mellitus. The present study investigated insulin sensitivity and secretion, visceral adiposity (VAT), and cardiovascular disease (CVD) risk profile in black obese adolescents (BOA) vs. white obese adolescents (WOA). Twenty-four BOA and 26 WOA underwent a hyperinsulinemic-euglycemic clamp to assess insulin sensitivity, a hyperglycemic clamp to determine insulin secretion, dual energy x-ray absorptiometry for body composition and computed tomography scan at L4-L5 to measure VAT and sc abdominal adipose tissue. Fasting lipid and automated blood pressure measurements were obtained. The WOA and BOA groups were divided into low VAT and high VAT groups. BOA compared with WOA of similar body mass index and percent body fat had less visceral adiposity, lower hepatic glucose production, and lower lipid levels. Visceral adiposity was associated with lower insulin sensitivity in both groups [low vs. high VAT; BOA, 2.9 +/- 0.4 vs. 1.7 +/- 0.2 micromol/kg x min per pmol/liter (P = 0.016); WOA, 2.6 +/- 0.5 vs. 1.5 +/- 0.1 (P = 0.032)]. However, this was compensated by higher insulin secretion in whites (low VAT, 934.8 +/- 121.8; high VAT, 1590.6 +/- 232.8 pmol/liter; P = 0.037), but not in blacks (low VAT, 1398.9 +/- 214.0; high VAT, 1423.7 +/- 108.7 pmol/liter). Glucose disposition index (insulin sensitivity x first phase insulin) was lower in high VAT vs. low VAT BOA, but not in WOA. In each racial group, high VAT groups had elevation of systolic and diastolic blood pressure, but dyslipidemia was worse in WOA with high VAT. In conclusion, a given level of body mass index confers different metabolic risks for WOA vs. BOA. Although differences in fat patterning may help explain the more atherogenic risk profile in whites, the cause of the more diabetogenic insulin sensitivity/secretion profile in blacks remains unknown and needs to be investigated further.

Adipose Tissue↗

Diminished antibody response to hepatitis B immunization in children with sickle cell disease.

Hepatitis B surface antibody titers were routinely measured in 150 children with sickle cell disease (SCD) after immunization, and the seroconversion rate was found to be lower than that in the general population (89% vs. 97%, P = 0.002). Most of the children who did not seroconvert after the series of 3 immunizations responded to booster injections (93%). Therefore, we recommend the measurement of hepatitis B surface antibody titers after immunization in those children with SCD at greatest risk for hepatitis B infection. An additional dose of hepatitis B vaccine should be administered to those without evidence of seroconversion.

Anemia, Sickle Cell↗