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Biomedical subjects

R M Laxer

Publications and source records attributed to R M Laxer.

At least 19 recordsLinked to original sources
PubMed1996

Antiribosomal P antibodies in pediatric patients with systemic lupus erythematosus and psychosis.

OBJECTIVE: To study antibodies directed against ribosomal P proteins, a sensitive and specific marker of depression and psychosis in systemic lupus erythematosus (SLE), in pediatric patients with SLE. METHODS: One hundred six serum samples were obtained from 79 patients with SLE. Sixty age- and sex-matched control sera were obtained, and 12 samples were obtained from children with primary psychosis. Antibodies to recombinant ribosomal P (rRP) protein were detected using a standard enzyme-linked immunosorbent assay. RESULTS: All 12 children with non-SLE-associated psychosis had normal levels of anti-rRP antibodies. Elevated levels of anti-rRP were found in 11 of 64 pediatric SLE patients without a history of psychosis (17%). In the group of 13 SLE patients with psychosis, 5 (38%) had increased anti-rRP antibody levels during the time of acute psychosis, and which significantly decreased during remission. In addition, most of the SLE patients without a history of psychosis had a good correlation between anti-rRP antibody levels and disease activity. The patients with psychosis had significantly less renal involvement than the patients without a history of psychosis. This apparent protection from renal disease was not related to the presence or absence of either antiribosomal P or anti-DNA antibodies. CONCLUSION: Elevated serum levels of antibodies to ribosomal P protein can distinguish SLE-associated psychosis from primary psychosis of childhood. In SLE, elevated antiribosomal P antibody levels were not specific for psychosis. Serial assays were useful for monitoring the disease activity.

Antibodies, Anti-Idiotypic↗
PubMed1996

Long-term outcome of mothers of children with complete congenital heart block.

OBJECTIVES: To determine the health of mothers of offspring with complete congenital heart block (CHB) both at the time of delivery of the affected child and in the long-term, and the percentage of mothers and children with CHB who had anti-SSA/Ro and/or SSB/La antibodies. PATIENTS AND METHODS: Sixty-four mothers of 64 children with CHB (seen between 1964 and 1993) were identified through the Cardiology database of The Hospital for Sick Children, Toronto, Canada. Medical information from these of children with CHB was evaluated. Data were obtained from the mothers by mailed questionnaire, telephone interview, and/or from the attending physicians. The presence of anti-Ro antibodies and anti-La antibodies were evaluated by ELISA assay. RESULTS: The mean age at the time of delivery of the first child with CHB was 28 +/- 6 years. At the time of delivery 42 (66%) mothers were healthy, 2 (3%) had systemic lupus erythematosus (SLE), 2 (3%) had linear scleroderma, 2 (3%) had rheumatoid arthritis; 3 (5%) had a history of rheumatic fever (but were otherwise well), 1 (2%) had Sjogren's syndrome (SS), and 12 (19%) had an undifferentiated autoimmune syndrome (UAS) (arthralgia, myalgia, photosensitivity, skin vasculitis, Raynaud's phenomenon). The mean time to follow-up from deliver to study was 121 +/- 88 months. The mean maternal age at study was 38 +/- 9 years. Three of 12 mothers who initially had a UAS progressed to SLE (average follow-up time of 80 months, median 96), and 2 developed SS (with average follow-up time 140 months, median 132) and 1 went into remission. The mean follow-up time for the other mothers who did not develop an autoimmune disease was 150 +/- 102 months. Thirty-six of the 42 initially healthy mothers remained well. One mother developed SLE; 1 developed hyperthyroidism; 1 developed anky-losing spondylitis; and 3 developed an UAS. The mean follow-up time of the 36 mothers who remained healthy was similar (123 +/- 97 months) to the 6 initial healthy mothers who developed an autoimmune disease (121 +/- 36 months). Anti-Ro and/or anti-La antibodies were positive in 32 of 53 (60%) mothers tested. Fourteen of the 53 mothers were symptomatic at the time of delivery and 39 were asymptomatic. Anti-Ro and/or anti-La antibodies were positive in 12 of 13 mothers tested at the time of delivery. CONCLUSIONS: The long-term maternal outcome in our cohort was very good as most of the initially healthy mothers remained well at follow-up. Twenty-five percent of the mothers with a UAS and only 2% of the initially healthy mothers developed SLE. The development of an autoimmune disease in an asymptomatic mother identified by the birth of a child with CHB was less common in our study than in previous studies. However, close follow-up of mothers with UAS is warranted.

Adult↗
PubMed1996

Seasonal onset of systemic-onset juvenile rheumatoid arthritis.

OBJECTIVE: This study was undertaken to investigate the recent finding of a seasonal difference in the onset of systemic-onset juvenile rheumatoid arthritis (SoJRA). We hypothesized that a seasonal onset pattern might implicate on infectious agent as a cause of SoJRA. METHODS: The date of onset was collected from the records of all patients with SoJRA from 1980 to 1992 at presentation to pediatric rheumatology clinics across Canada. The onset pattern of SoJRA was then compared with incidence data on viral infections obtained for the same period. RESULTS: Across Canada the onset of SoJRA was constant across the seasons. However, in the Prairie region there was a statistically significant seasonal pattern, with peaks in autumn and early spring. We could find no evidence that viral incidence correlated with disease incidence either throughout Canada or in the Prairie region. CONCLUSIONS: If a seasonal infectious agent causes SoJRA, then it is likely only one of several causes and may act only in certain regions. Future studies should be carried out in those areas where SoJRA does have a seasonal onset pattern.

Adolescent↗
PubMed1996

Accelerated nodulosis during methotrexate therapy for juvenile rheumatoid arthritis.

We describe two patients with rheumatoid factor-positive, polyarticular-onset juvenile rheumatoid arthritis in whom accelerated nodulosis developed during methotrexate therapy. Although they had only a few nodules at diagnosis, the nodules increased in number and size 3 to 4 months after the start of methotrexate therapy in both patients. The nodules regressed after withdrawal of methotrexate therapy in one patient and were arrested with the addition of hydroxychloroquine in the other. Physicians treating patients with methotrexate for juvenile rheumatoid arthritis must be aware of this extraarticular side effect.

Adolescent↗
PubMed1996

Intravenous immunoglobulin in rheumatic disease.

With the advent of numerous commercial preparations of intravenous immunoglobulin preparations since 1981, it is now possible to administer these preparations in significant quantities to cause elevation of serum immunoglobulin levels both in patients with antibody-deficient states and in those with normal circulating immunoglobulin levels. This led to a report of dramatic improvement of thrombocytopenia in a child with agammaglobulinemia following the use of intravenous immunoglobulin preparations for recurrent infections, and further studies in both children and adults with associated symptoms suggested therapeutic efficacy of intravenous immunoglobulin preparations in controlling autoimmune symptoms.

Costs and Cost Analysis↗
PubMed1996

CT appearance of pulmonary vasculitis in children.

OBJECTIVE: The aim of this study was to determine whether a CT pattern that may represent early or subtle changes of pulmonary vasculitis in children exists. MATERIALS AND METHODS: High-resolution CT scans of the chest for 107 children were retrospectively reviewed by two radiologists who were unaware of the original study findings. Chest CT scans (conventional) for another 54 children who had symptoms or a diagnosis of vasculitis also were reviewed. RESULTS: We identified hazy or fluffy centrilobular, perivascular densities in 10 children, two of whom had small airways disease and eight of whom had vasculitis (Wegener's granulomatosis [n = 5], systemic lupus erythematosus [n = 1], scleroderma-polymyositis overlap syndrome [n = 1], and Churg-Strauss syndrome [n = 1]). The latter eight children underwent 35 scans, 17 of which were positive for these perivascular densities. All positive scans were associated with active disease of new onset (5/17) or with clinical exacerbation of preexisting systemic disease (12/17). The positive scans also were associated with an elevated erythrocyte sedimentation rate (13/17) and biopsy evidence of vasculitis from a variety of sites, including the lungs (n = 1), kidneys (n = 7), oropharynx (n = 5), skin (n = 9), lymph nodes (n = 1), and myocardium (n = 2). The single lung biopsy showed an angiocentric inflammatory-hemorrhagic process. Of the five patients who had positive scans, underwent therapy, and then had repeat studies, four patients had scans revert to normal in association with inactive disease. The remaining patient whose scan did not normalize failed to respond to treatment. CONCLUSION: The fluffy centrilobular pattern likely represents subtle changes of pulmonary vasculitis. In the appropriate clinical setting, such a finding may obviate the need for a lung biopsy.

Adolescent↗
PubMed1996

Intravenous immunoglobulin therapy in systemic onset juvenile rheumatoid arthritis: a followup study.

OBJECTIVE: To report the short and longterm effect of intravenous immunoglobulin (IVIG) in patients with systemic onset juvenile rheumatoid arthritis (SOJRA). METHODS: A retrospective chart review of 27 patients with SOJRA treated with IVIG and followed for 37.1 +/- 18.2 months was undertaken. Indications for treatment were fever, arthritis, or steroid dependency. RESULTS: We treated 27 patients with SOJRA with IVIG monthly for 3-54 months. Six months after IVIG therapy, 20 patients had a least a 50% decrease in at least one of the following: the number of days of fever; prednisone dose; or the number of active joints. Five patients failed to respond to IVIG, and 2 dropped out after 3 and 4 months. At last followup visit (mean 37.6 +/- 18 months), 11 of the initial 20 responder group patients were in remission, while 3 had significantly improved but still had active arthritis, and 6 were now unresponsive. Of the initial 5 patients in the nonresponder group, 4 had nonresponsive arthritis and 1 had improved at last followup. Three patients in the responder group subsequently developed other diseases. CONCLUSION: The main benefit of IVIG therapy to most of our patients was a significant improvement in the systemic features, with resolution of fever and a significant reduction in the steroid dose. The efficacy of IVIG in altering the course of arthritis was less predictable. We suggest that IVIG has a role in the management of SOJRA, but it should be limited to patients with severe SOJRA in whom prolonged unresponsiveness to standard therapy is present.

Adolescent↗
PubMed1996

Analysis of T cell receptor gamma transcripts in right and left knee synovial fluids of patients with rheumatoid arthritis.

OBJECTIVE: To establish the extent of clonal expansion of T cell receptor (TCR) gamma delta + T cells in synovial fluid (SF), and the sharing of the clones between affected knee joints from patients with rheumatoid arthritis (RA). METHODS: We quantified, using the polymerase chain reaction (PCR), the level of expression from each of the 4 V gamma gene families. We resolved PCR products on denaturing polyacrylamide gels to measure the proportion of mRNA transcripts contributed by clonally expanded gamma delta T cells. We subcloned and sequenced 509 cDNA clones derived from 8 SF and one peripheral blood sample from 2 patients with RA and one patient with juvenile onset RA to fully characterize the populations of T cell receptor gamma mRNA sequences. RESULTS: We found in each patient disproportionate expression of a subpopulation of T cell receptor gamma mRNA transcripts. Some of these transcripts are expressed by T cells found in both joints. CONCLUSION: Synovial TCR gamma delta + T cells are oligoclonal and some of these T cell clones are common to SF of both joints. The finding of identical T cell sequences from SF of both affected joints from each patient points to a role for gamma delta + T cells in disease progression.

Amino Acid Sequence↗
PubMed1996

Clinical significance of specific autoantibodies in juvenile dermatomyositis.

OBJECTIVE: To determine the prevalence and clinical association of myositis specific antibodies in an unselected group of patients with juvenile dermatomyositis (DM). METHODS: The sera of 42 subjects, representing an unselected group of patients from a single center, with juvenile DM and 7 others with idiopathic inflammatory myopathy (IIM) were examined for the presence of myositis specific antibodies by immunodiffusion against calf thymus extract and immunoprecipitation with HeLa extract. RESULTS: Of the subjects with juvenile DM, only 2 had evidence of antibodies specific to myositis (anti-Mi2). Three other patients with juvenile DM had defined autoantibodies not usually considered to be specific to myositis. Two of the 3 subjects had anti-PM-Scl; both developed features of scleroderma after the juvenile DM remitted. The 5 subjects with defined autoantibodies did not differ clinically from the remainder of the subjects with the exception of the late development of scleroderma features in 2. Fourteen other subjects with juvenile DM had unidentified bands on immunoprecipitation, which may represent as yet undiscovered myositis specific antibodies. No myositis specific antibodies were detected in any of the 7 subjects with other IIM syndromes. CONCLUSION: Based on our findings, we do not recommend routine clinical testing for these antibodies in children with typical juvenile DM. Further study of the unidentified bands seen in our subjects may lead to better understanding of the clinical groupings and etiopathogenesis of childhood myositis.

Adolescent↗
PubMed1995

Neurologic manifestations of pediatric systemic lupus erythematosus.

Central nervous system involvement is a common but rarely reviewed feature of pediatric systemic lupus erythematosus (SLE). We retrospectively reviewed the charts of 91 patients with pediatric SLE and using a standardized data abstraction form documented 40 patients with central nervous system (CNS-SLE) involvement. The mean age of onset of SLE was 13.3 years. In 19 patients the CNS manifestation was a presenting symptom, in 12 patients CNS involvement was present within the first year of diagnosis, and in 9 patients it took up to 7 years for CNS disease to become evident. Nineteen children (48%) manifested neuropsychiatric SLE, which included depression, concentration or memory problems, and frank psychosis. Seizures were present in 8 patients (20%), 6 had cerebral ischemic events (15%), 1 had chorea (3%), 2 had papilledema (5%), and 2 patients had a peripheral neuropathy (5%). Nine patients (22%) had severe headache consistent with lupus headache. Seven children had more than one CNS manifestation. In the investigation of CNS-SLE, computed tomography and/or magnetic resonance imaging scans were helpful in patients with focal ischemic lesions and venous sinus thrombosis. Electroencephalography was abnormal only in 33% of patients with seizure disorders and rarely helpful in patients with diffuse neuropsychiatric symptoms. Single-photon emission computed tomography scans were abnormal in most patients with neuropsychiatric SLE, especially in those with frank psychosis. The lupus anticoagulant was present in the patient with chorea and was frequently present in patients with cerebral vascular events. Long-term outcome was good: only 1 child died of cerebral hemorrhagic infarction and 3 others had significant persistent CNS deficits. The majority of patients (90%) had excellent recovery from CNS-SLE.

Adolescent↗
PubMed1995

Cerebral vein thrombosis in childhood systemic lupus erythematosus.

We describe three cases of cerebral vein thrombosis (CVT) in girls with systemic lupus erythematosus. Severe, persistent, unremitting headache was a common manifestation. In the first patient, although the clinical features were suggestive of CVT, the diagnosis was delayed and she had a significant cerebral infarct. In the other two patients the diagnosis was made earlier and led to more rapid treatment; the institution of early therapy may have prevented further sequelae. The CVT was diagnosed in all patients with a combination of computed tomography and magnetic resonance imaging studies without the need for angiography. All patients were treated for their underlying systemic lupus erythematosus and with anticoagulation. All are receiving long-term low doses of warfarin and have not had any recurrences.

Adolescent↗
PubMed1995

Scleroderma in children.

Childhood scleroderma may present in a variety of clinical forms that differ in clinical presentation, extracutaneous features, clinical course, and outcome. All include hardening of the skin as a major feature. This article reviews these various entities, focusing on primarily the clinical features. In addition, current concepts regarding pathogenesis and treatment are discussed.

Adolescent↗
PubMed1995

Evaluation of the cytokine response in Kawasaki disease.

Intracellular cytokines interleukin 6, tumor necrosis factor (TNF) alpha and TNF-beta were studied in peripheral blood mononuclear cells of patients with Kawasaki disease during the acute, subacute and convalescent stages of the disease utilizing cytokine-specific monoclonal antibodies and indirect immunofluorescence. Intracellular cytokines TNF-alpha and -beta were present only during the acute stage before initiation of therapy and not in the subacute or convalescent phase. Intracellular interleukin 6 was seen in both the acute phase and, in small numbers of patients, in the subacute stage of the illness. Overall 15 of 25 (60%) patients produced at least one intracellular cytokine. In the acute stage both monocyte and lymphocyte cytokines were detected intracellularly, TNF-alpha and TNF-beta in 58% of patients whereas interleukin 6 was seen in only 16%. This study provides evidence to support the involvement of activated mononuclear cells, both T cells and monocytes and their secreted soluble products, cytokines, in the pathogenesis of Kawasaki disease.

Acute Disease↗
PubMed1995

Autoantibody response to the Ro/La particle may predict outcome in neonatal lupus erythematosus.

This study was undertaken to determine the role of antibodies against both recombinant Ro (r-Ro) and La (r-La) proteins and polypeptides derived from the recombinant La protein in predicting fetal and neonatal outcome in children at risk to develop neonatal lupus erythematosus (NLE). All sera were obtained in the perinatal period and quantitative ELISA assays were used. We collected 41 maternal sera within 2 months of delivery of a child with NLE (21 with congenital heart disease block (CHB) and 20 with dermatologic NLE) and 19 sera from anti-Ro and/or anti-La antibody-positive mothers with systemic lupus erythematosus (SLE) who delivered a child without NLE. All sera were tested for anti-r-La and anti-r-Ro antibodies by ELISA, and most sera were tested for antibodies directed against La polypeptides by immunoblot. We found significantly higher anti-r-La antibody levels in the sera from mothers of children with NLE compared with sera from mothers of unaffected children (0.67 +/- 0.43 versus 0.14 +/- 0.30; P < 0.0001). There was a statistically significant difference in the mean anti-r-La levels between the sera of mothers of children with CHB compared with dermatologic NLE (0.51 +/- 0.45 versus 0.83 +/- 0.37 respectively; P = 0.0091). When we examined antibodies directed against the recombinant 52-kD Ro protein, there was a statistically significant elevation of titres in the sera of mothers of NLE children (0.77 +/- 0.35) compared with non-NLE mothers (0.29 +/- 0.39; P < 0.0001). There was no difference in the r-Ro levels between mothers of children with dermatologic NLE compared with CHB (0.82 +/- 0.37 versus 0.71 +/- 0.74; P = 0.32). When we examined polypeptides derived from the recombinant La protein, the mean number of polypeptides recognized by sera from mothers of children with NLE was significantly higher than the mean number of polypeptides recognized by sera from mothers of unaffected children (5.1 +/- 0.54 versus 2.3 +/- 0.54 respectively; P < 0.001). More importantly, when we examined the individual polypeptides, we found that only sera from mothers of children with NLE and not from mothers of unaffected children recognized a polypeptide designated DD (30% versus 0%, respectively). These studies indicate that the autoantibody response to the Ro/La particle can differentiate sera from mothers of children with NLE and sera from mothers of unaffected children. Furthermore, there was a difference in the anti-La autoantibody response between mothers of children with CHB and dermatologic NLE.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoantibodies↗
PubMed1995

Experience with misoprostol therapy for NSAID gastropathy in children.

OBJECTIVE: To determine the effect of misoprostol, a synthetic prostaglandin E1 analogue, on the gastrointestinal tract (GIT) symptoms associated with non-steroidal anti-inflammatory drug (NSAID) administration and on the haemoglobin value, in children. METHODS: Retrospective chart review of children attending the paediatric rheumatology clinic at a tertiary referral hospital over a three year period, who were receiving NSAIDs and were prescribed misoprostol for treatment of GIT symptoms or anaemia. RESULTS: Twenty five children (mean age 12.0 (SD 2.8) (range 7-17) years were prescribed misoprostol (mean dose 308.4 (76.5) micrograms/m2/day; 9.8 (2.5) micrograms/kg/day) while NSAID therapy was continued. Of the 22 (88%) patients with GIT complaints, 18 (82%) had complete resolution of symptoms and two (9%) had some improvement. Four patients (18%) had a recurrence of symptoms after initial resolution while still receiving misoprostol. Misoprostol therapy was associated with a statistically significant increase in haemoglobin concentration (mean value before misoprostol 115 (18) g/l; after misoprostol 126 (15) g/l (p = 0.02)). The only adverse effect reported was self limited diarrhoea in one child. CONCLUSION: Misoprostol appeared to be effective in the treatment of GIT symptoms in children receiving NSAIDs and to result in significant increase in the haemoglobin concentration. Further prospective studies are needed to evaluate the role of misoprostol therapy for NSAID associated GIT complaints in the paediatric population.

Abdominal Pain↗
PubMed1995

Influence of food on the bioavailability of oral methotrexate in children.

OBJECTIVE: To determine the bioavailability of oral methotrexate (MTX) in patients with juvenile rheumatoid arthritis in the fasting and fed states. METHODS: Each patient randomly received their usual weekly MTX dose either orally (po) after an overnight fast, po immediately after a breakfast of their choice, or intravenously (iv) on 3 consecutive weeks. Blood samples were taken at 0, 0.5, 1, 1.5, 2, 3, 4, and 6 h after po and 0, 0.08, 0.25, 0.5, 1, 1.5, 2, 3, 4, and 6 h after iv administration. RESULTS: Fourteen patients (10 female) aged 2.8 to 15.1 yrs completed the study; the results of 13 patients were evaluable. The mean elimination rate constant was 0.27 +/- 0.065, 0.26 +/- 0.067, and 0.25 +/- 0.11 h-1 after po fasting, po fed, and iv administration, respectively. The total area under the serum concentration vs time curve was 1.87 +/- 0.83, 1.50 +/- 0.51, and 1.85 +/- 0.80 mumol/l.h after po fasting, po fed, and iv administration, respectively. The maximum serum MTX concentration (Cmax) was 0.65 +/- 0.33 and 0.39 +/- 0.18 mumol/l after po fasting and po fed administration, respectively (p = 0.0022). The time to Cmax was 0.94 +/- 0.40 and 1.32 +/- 0.68 h after po fasting and po fed administration, respectively (p = 0.1464). The bioavailability of oral MTX while fasting was 1.1 +/- 0.51, while that after a meal was 0.88 +/- 0.35 (p = 0.0211). CONCLUSION: These data indicate greater oral bioavailability of MTX in the fasting state. We recommend that children receive MTX on an empty stomach.

Administration, Oral↗
PubMed1995

Radiologic features of systemic onset juvenile rheumatoid arthritis.

OBJECTIVE: To document the radiologic abnormalities in patients with systemic onset juvenile rheumatoid arthritis (SOJRA) including abnormalities occurring early in the course of disease. METHODS: A retrospective review of the charts and radiographs of 42 consecutive children with SOJRA was carried out. Radiographs were reviewed by a single experienced radiologist with no knowledge of the clinical course of the patients. RESULTS: Soft tissue swelling and osteoporosis were the most common radiologic abnormalities (34/42; 81%). Cartilage loss and/or bone erosions were also common, occurring in 50% of patients. Erosions occurred within 2 years of disease onset in 11/36 (31%). Subchondral irregularity and sclerosis within 2 years of disease onset preceded erosions in 11 patients with serial radiographs. Severe radiologic abnormalities included joint ankylosis (8/42; 19%), subluxation (9/42; 21%), and protrusio acetabuli (4/42; 10%). Joint ankylosis occurred most commonly between 3 and 5 years after disease onset and subluxation between 2 and 6 years. CONCLUSION: A subgroup of children with SOJRA develops early destructive radiologic changes whose severity is comparable to those of children with rheumatoid factor positive polyarticular JRA. Early subchondral changes may be predictive of subsequent erosive disease in SOJRA and require prospective study using newer imaging techniques.

Adolescent↗