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Biomedical subjects

K S Barron

Publications and source records attributed to K S Barron.

At least 19 recordsLinked to original sources
PubMed2001

Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela.

OBJECTIVE: We report 16 infants with complete congenital heart block (CHB) who developed late-onset dilated cardiomyopathy despite early institution of cardiac pacing. BACKGROUND: Isolated CHB has an excellent prognosis following pacemaker implantation. Most early deaths result from delayed initiation of pacing therapy or hemodynamic abnormalities associated with congenital heart defects. METHODS: A multi-institutional study was performed to identify common clinical features and possible risk factors associated with late-onset dilated cardiomyopathy in patients born with congenital CHB. RESULTS: Congenital heart block was diagnosed in utero in 12 patients and at birth in four patients. Ten of 16 patients had serologic findings consistent with neonatal lupus syndrome (NLS). A pericardial effusion was evident on fetal ultrasound in six patients. In utero determination of left ventricular (LV) function was normal in all. Following birth, one infant exhibited a rash consistent with NLS and two had elevated hepatic transaminases and transient thrombocytopenia. In the early postnatal period, LV function was normal in 15 patients (shortening fraction [SF] = 34 +/- 7%) and was decreased in one (SF = 20%). A cardiac pacemaker was implanted during the first two weeks of life in 15 patients and at seven months in one patient. Left ventricular function significantly decreased during follow-up (14 days to 9.3 years, SF = 9% +/- 5%). Twelve of 16 patients developed congestive heart failure before age 24 months. Myocardial biopsy revealed hypertrophy in 11 patients, interstitial fibrosis in 11 patients, and myocyte degeneration in two patients. Clinical status during follow-up was guarded: four patients died from congestive heart failure; seven required cardiac transplantation; one was awaiting cardiac transplantation; and four exhibited recovery of SF (31 +/- 2%). CONCLUSIONS: Despite early institution of cardiac pacing, some infants with CHB develop LV cardiomyopathy. Patients with CHB require close follow-up not only of their cardiac rate and rhythm, but also ventricular function.

Cardiomyopathy, Dilated↗
PubMed2001

Autologous stem cell transplantation for pediatric rheumatic diseases.

The National Institute of Allergy and Infectious Disease, National Institutes of Health, convened a workshop entitled The Next Step: Protocol Development for Autologous Stem Cell Transplantation for Pediatric Rheumatic Disease, June 2000, co-chaired by Drs. Karyl Barron and Carol Wallace. The goal of the workshop was to focus on the scientific rationale for stem cell transplantation therapy in the pediatric diseases, unique aspects of this therapy in the pediatric rheumatic diseases, transplantation issues and options, regulatory issues, and development of a DNA repository for these diseases.

Child↗
PubMed1999

A staged approach to the treatment of Wegener's granulomatosis: induction of remission with glucocorticoids and daily cyclophosphamide switching to methotrexate for remission maintenance.

OBJECTIVE: To determine the efficacy of a daily cyclophosphamide (CYC) and glucocorticoid induction and methotrexate (MTX) remission-maintenance regimen for the treatment of Wegener's granulomatosis (WG). METHODS: An open-label, prospective, standardized trial for the treatment of WG was performed using CYC and glucocorticoids for remission induction and MTX for remission maintenance. Thirty-one patients were enrolled in this study. Outcome was assessed using predetermined definitions based on clinical characteristics and pathologic, laboratory, and radiographic findings. RESULTS: The use of CYC and glucocorticoids for remission induction and MTX for remission maintenance resulted in disease remission for all 31 patients. The median time to remission was 3 months and the median time to discontinuation of glucocorticoids was 8 months. No patients have died, and 5 patients (16%) have had disease relapses at a median of 13 months after achieving remission. Only 2 patients (6%) have had to withdraw from the trial as a result of medication toxicity. CONCLUSION: The use of CYC and glucocorticoids for remission induction and MTX for remission maintenance was shown by this study to be an acceptable alternative therapy for patients with active WG, including those with severe disease at onset.

Adolescent↗
PubMed1999

Report of the National Institutes of Health Workshop on Kawasaki Disease.

The National Institute of Allergy and Infectious Disease, National Institutes of Health convened a workshop on Kawasaki disease, May 1997, co-chaired by Drs. Karyl Barron and Stanford Shulman. The goal of the workshop was to review the latest scientific advances relating to the epidemiology, etiology, pathogenesis, treatment, and complications of Kawasaki disease, along with future therapeutic options and proposed future research directions.

Coronary Disease↗
PubMed1998

Kawasaki disease in children.

Kawasaki disease is an acute systemic vasculitis of childhood. Children are predominantly affected at less than 5 years of age, and coronary artery involvement is responsible for most of the morbidity and mortality of the disease. Since the institution of intravenous immune globulin in the treatment of the disease, outcome has significantly improved. Although multiple infectious agents and toxins have been implicated in the etiology of the disease, none has been identified. Activation of the immune system is known to occur in the acute stage of the disease and plays an important role in the pathogenesis of the disease.

Cardiovascular Diseases↗
PubMed1995

Susceptibility to Reiter's syndrome is associated with alleles of TAP genes.

OBJECTIVE: Although HLA-B27 is strongly associated with susceptibility to Reiter's syndrome (RS), recent data suggest that an additional modifying or susceptibility gene(s) acts in concert with HLA-B27 to contribute to disease pathogenesis. The recently described TAP genes (transporters associated with antigen processing) are potential candidates because they are polymorphic and their function is to transport antigenic peptides to be loaded in HLA class I molecules. METHODS: TAP1 and TAP2 alleles were determined for 34 patients with RS (28 HLA-B27 positive, 6 HLA-B27 negative), and their frequencies were compared with those observed for 52 HLA-B27 positive and 80 random disease-free control subjects. RESULTS: The allele frequency of TAP1C was greater in patients with RS (8 of 62, 13%) than in random controls (5 of 160, 3%) (P = 0.009). The frequency of TAP2A was greater in RS patients (51 of 66, 77%) than in random controls (88 of 160, 55%) (P = 0.002); likewise, the frequency was greater in HLA-B27 positive RS patients (41 of 54, 76%) than in HLA-B27 positive disease-free controls (49 of 94, 52%) (P = 0.004). Furthermore, the TAP2A allele was present in all RS patients (100%), whereas TAP2A was present in 79% (63 of 80) of the random controls (P = 0.003). CONCLUSION: The association observed between TAP alleles and RS is independent of the presence of HLA-B27, and despite the physical proximity of TAP and HLA class II genes, linkage disequilibrium does not account for the observed associations between TAP and RS. Thus, TAP genes are genetically separated but functionally linked to class I genes, and both contribute to susceptibility to RS.

ATP-Binding Cassette Transporters↗
PubMed1995

TCRBV12 genes are polymorphic but the protein products encoded by each gene are conserved.

The human TCRBV gene complex contains three BV12 genes and all are polymorphic. There are two alleles of BV12S4; one allele contains a stop codon in the coding region which precludes its expression. There are four alleles of BV12S2 and two alleles of BV12S3 genes; however, the substitutions present in both genes are conservative. Although allelic variants exist for each of the three BV12 genes, only one protein product is encoded by each gene.

Alleles↗
PubMed1994

The human T-cell receptor variable gene segment TCRBV6S1 has two null alleles.

The extent of polymorphism in TCRBV6S1 was examined by screening 203 individuals of diverse ethnic backgrounds by using SSCP. Three alleles were detected, including two that were described previously (TCRBV6S1*1 and *2P). The third allele (TCRBV6S1*3P), identified in these studies, is a pseudogene because, similar to allele *2P, it contains a substitution of a highly conserved cysteine residue near CDR3. Among a panel of 126 Caucasian donors, alleles *1, *2P, and *3P were observed to have frequencies of 0.72, 0.12, and 0.16, respectively. The extent of this survey suggests that it is unlikely for there to be additional common variants of TCRBV6S1. The approach used here enables rapid typing for polymorphism in a TCRBV gene that results in an allelically determined hole in the TCR repertoire.

Alleles↗
PubMed1993

Clinical, serologic, and immunogenetic studies in childhood-onset systemic lupus erythematosus.

OBJECTIVE: To determine the frequency of systemic lupus erythematosus (SLE)-associated clinical manifestations, autoantibodies, and HLA class II alleles in a large cohort of patients with childhood-onset SLE. METHODS: Eighty children with SLE onset before age 18 (27 before age 11) were studied for the frequency of renal, neuropsychiatric, and hematologic complications as well as for anti-native DNA, Ro, La, Sm, and U1 RNP autoantibodies. HLA-DR, DQ, and DP alleles were determined by oligotyping. The results were compared with findings in 213 adults with SLE onset at or after age 18 years. RESULTS: Renal involvement was more frequent in those with childhood-onset SLE, especially those with onset before age 11 (82%, compared with 53% in adults). Anti-U1 RNP was more common in American blacks with SLE onset before age 18. HLA-DRB1*0301, DQA1*0501, DQB1*0201 was more common in Caucasians and DRB1*1503, DRB5*0101, DQA1*0102, DQB1*0602 in American blacks, regardless of age at SLE onset. Anti-Sm autoantibodies were most highly associated with HLA-DQA1*0102 and DQB1*0602. CONCLUSION: While childhood-onset SLE shares many immunogenetic and serologic similarities to adult-onset disease, important clinical differences nevertheless exist in children with this disease.

Adolescent↗
PubMed1992

DNA analysis of HLA-DR, DQ, and DP alleles in children with polyarticular juvenile rheumatoid arthritis.

HLA-DR, DQ and DP alleles were determined by restriction fragment length polymorphism analysis and oligonucleotide probe hybridization of polymerase chain reaction amplified genomic DNA in 94 Caucasian children with polyarticular juvenile rheumatoid arthritis (JRA) [13 rheumatoid factor (RF)+ and 81 RF-] and 100 healthy controls. HLA-DRw8, DQw4, DQA1*0401, DQB1*0402 were increased in frequency in those patients with RF seronegative disease, with highest frequencies seen in patients with young age at onset (< 5 years of age). These findings were similar to what we observed in children with pauciarticular JRA, especially those with young age at onset. DPB1*0301 was also found in increased frequency in the RF- group, and in particular those seronegative for antinuclear antibody. In contrast to what is observed in patients with pauciarticular JRA, the frequency of DPB1*0201 was not increased in any polyarticular JRA patient group. These data suggest that polyarticular JRA shares many genetic features with pauciarticular JRA.

Alleles↗
PubMed1992

Major histocompatibility complex class II alleles in Kawasaki syndrome--lack of consistent correlation with disease or cardiac involvement.

Recent refinements in molecular genetic typing have allowed the precise determination of the extensive polymorphism now recognized in class II major histocompatibility complex (MHC) genotypes. This could have important applications in Kawasaki syndrome (KS), where the relative contribution of genetic factors is now well known. Accordingly, 44 Caucasian, 13 Asian, and 5 American black patients, as well as 221 Caucasian controls were typed for HLA-DRB1, DRB3, DRB4, DQA1, DQB1, and DPB1 alleles by oligonucleotide probe hybridization of polymerase chain reaction amplified genomic DNA using probes and primers supplied by the 11th International Histocompatibility Testing Workshop. Among the 15 HLA-DRB1, 3 DRB3, 9 DQA1, 15 DQB1, and 19 DPB1 alleles examined, none were found to be significantly associated with KS, except for an increased frequency of HLA-DRB3*0301 in Houston Caucasian patients when compared to Houston Caucasian controls (38 vs 11%, pc = 0.012, RR = 5.0). Twelve patients developed coronary artery involvement of whom 7 had aneurysms and 5 had dilatation (8 Caucasians, 2 blacks, 2 Asians). No specific HLA class II allele was associated with this disease complication. Despite a regional association, our data fail to support a consistent role for MHC class II alleles in the pathogenesis of KS.

Alleles↗
PubMed1992

Intravenous immunoglobulin therapy: magic or black magic.

Intravenous immunoglobulin (IVIG) therapy has been used not only as replacement treatment for immunodeficiency, but also as treatment of autoimmune diseases, specifically Kawasaki disease, systemic juvenile arthritis and juvenile dermatomyositis. In Kawasaki disease, IVIG reduces the incidence of coronary artery abnormalities, as well as rapidly improving clinical and laboratory variables such as fever and rash, platelet count, white blood cell count and serum albumin. Furthermore, a single high dose of 2 g/kg is as effective as 400 mg/kg x 4 days. In systemic juvenile arthritis, followup of at least one year demonstrated that monthly treatment with IVIG resulted in improvement of systemic disease in 10/11 patients, allowed for cessation of prednisone treatment in 7/8 patients and significant improvement of arthritis in 8 patients. In juvenile dermatomyositis, we report 2 uncontrolled trials of IVIG treatment that resulted in significant clinical improvement and steroid-sparing. In contrast, IVIG treatment of systemic lupus erythematosus (SLE) resulted in improvement in 3 patients, but exacerbation or new onset of renal disease in 3 patients. Overall, our report demonstrates that IVIG has been effective both in a controlled trial in Kawasaki disease and in uncontrolled trials in systemic juvenile arthritis and juvenile dermatomyositis. We suggest that IVIG should be used cautiously in SLE.

Arthritis, Juvenile↗
PubMed1991

DNA analysis of HLA-DR, DQ and DP genes in pauciarticular juvenile rheumatoid arthritis.

HLA-DR, DQ, and DP alleles were determined by restriction fragment length polymorphism (RFLP) and oligonucleotide hybridization analysis in 50 Caucasian children with pauciarticular juvenile rheumatoid arthritis (PaJRA) and 82 controls. There was an increased frequency of DR5, DRw8, and DQw4, as well as individual DQ alpha and beta chains, DQA*0401 and DQB1*0402, respectively, in this group of patients. There was an absolute association between DRw8, DQw4, DQA1*0401, and DQB1*0402 in the patient population. HLA-DPw2.1 was also increased in frequency. There was little evidence of linkage disequilibrium found between DPw2.1 and DR5, DRw8, or DQw4. These MHC Class II associations were more characteristic of those patients with young age of onset (less than 5 years), rather than those with onset greater than or equal to 5 years of age. Our data confirmed the previous associations of HLA-DR5, DRw8, and DPw2.1 with PaJRA and suggested a new association for DQ alpha and beta genes in the clinical expression of this disease.

Alleles↗
PubMed1991

Kawasaki disease. Epidemiology, late prognosis, and therapy.

Kawasaki disease is an immunologically mediated diffuse vasculitis of childhood of unknown etiology. While most of the clinical features--including diffuse mucosal inflammation, indurative edema, rash, and lymphadenopathy--are self-limiting, coronary artery aneurysms and the possibility of thrombotic occlusion occurs in up to 20% of children. The epidemiologic and clinical features of this disease suggest an infectious etiology; however, a specific organism has not been consistently identified. An abnormal immune response to this as yet to be defined organism plays a critical role in the progression of this disease. The morbidity and mortality of this disease are related primarily to the potential cardiovascular complications. The natural history of the coronary artery aneurysms is that most lesions regress with time. Factors leading to a higher probability of regression include age less than 1 year, female sex, fusiform aneurysm, and maximum diameter less than 4 mm. Current recommendations for therapy include aspirin and IVIG. The range of dosages regimens for each medication are discussed in the text.

Aspirin↗
PubMed1991

Auranofin therapy for juvenile rheumatoid arthritis: results of the five-year open label extension trial.

Eighty-eight children with juvenile rheumatoid arthritis (JRA) who completed a double blind, randomized placebo controlled trial of oral gold were entered into an open label extension phase during which they received auranofin (AF) at a dosage of 0.15-0.2 mg/kg/day (9 mg/day maximum). Eleven (12.5%) patients completed 5 years of AF therapy; 77 (87.5%) did not. Fifteen (17%) of the 88 were in disease remission at the final visit. Mean duration of therapy for those who discontinued was 646 days. Parental/patient decision and insufficient therapeutic effect were the 2 most frequent reasons for early termination, followed by adverse effects. Though relatively well tolerated, AF provides adequate longterm management for only a small percentage of patients with JRA.

Administration, Oral↗
PubMed1990

Soluble interleukin-2 receptors in children with Kawasaki syndrome.

We studied levels of soluble interleukin-2 receptors (IL-2R) in serial serum samples obtained from 93 patients with Kawasaki syndrome, using a double-antibody "sandwich" enzyme-linked immunosorbent assay technique. Concentrations of soluble IL-2R were significantly increased in Kawasaki syndrome patients in the first 4 weeks of illness when compared with either healthy adult or pediatric controls (P less than 0.02), and in the first 2 weeks of illness when compared with a group of children with measles (P less than 0.0001). Furthermore, in the second week of illness, levels of soluble IL-2R were significantly greater in children who subsequently developed coronary artery aneurysms than in patients with normal appearing coronary arteries. Serum concentration of soluble IL-2R is a useful marker for detecting early Kawasaki syndrome and identifies those patients who are at greater risk of developing coronary artery aneurysms.

Adult↗
PubMed1990

Treatment of Kawasaki syndrome: a comparison of two dosage regimens of intravenously administered immune globulin.

Because intravenously administered immune globulin (IVIG) is effective in reducing the incidence of coronary artery aneurysms in Kawasaki syndrome when given at a dose of 400 mg/kg daily for 4 days, we undertook a multicenter clinical trial comparing two dosage regimens of IVIG. Patients were randomly assigned to receive IVIG at either 400 mg/kg daily for 4 days (22 patients) or 1 gm/kg as a single dose (22 patients). All patients received aspirin therapy, and all were enrolled within 7 days of onset of fever. The presence of coronary artery aneurysms was evaluated by means of two-dimensional echocardiography before infusion; at days 4 to 6, 14 to 21, and 42 to 49 after infusion; and at 1 year. Coronary artery aneurysms were detected in 3 of the 44 patients, including one patient receiving 400 mg/kg and two patients receiving 1 gm/kg (p value not significant). No giant aneurysms were detected. No major side effects occurred with either dosage regimen. Patients receiving the 1 gm/kg dose had a faster resolution of fever and were discharged from the hospital approximately 1 day sooner than the 400 mg/kg group (p = 0.01). Although the relatively small sample size in this trial does not allow for a more definitive statement regarding the occurrence of coronary artery aneurysms, it appears that the 1 gm/kg dose is associated with a more rapid clinical improvement and a shorter hospital stay.

Aspirin↗