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Biomedical subjects

James B Peter

Publications and source records attributed to James B Peter.

9 recordsLinked to original sources
PubMed2005

Elevated autoantibodies against oxidized palmitoyl arachidonoyl phosphocholine in patients with hypertension and myocardial infarction.

Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (oxPAPC) is antigenic and an important epitope of oxLDL. This study validates the assay for autoantibodies against oxPAPC (anti-oxPAPC-Ab) and investigates the possible association between anti-oxPAPC-Ab and cardiovascular disease. A synthetic PAPC was oxidatively modified as an antigen for the anti-oxPAPC-Ab assay. The concentrations of the antibody in serum were measured by EIA. The analytical parameters of the anti-oxPAPC-Ab assay were validated. Levels of anti-oxPAPC-Ab were prevalent in patients with hypertension, myocardial infarction (MI) and healthy subjects. Anti-oxPAPC-Ab specifically reacts with oxPAPC, but not with 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC). The characteristics of the assay included precision (inter-assay coefficients of variation were 7.9% for IgG and 13.2% for IgM), cross-reactivity, clinical sensitivity for hypertension (43% and 47%) and MI (37% and 41%), clinical specificity (95.2%) and normal values (less than 13 Unit/mL for IgG and less than 7 Unit/mL for IgM). Elevated levels of anti-oxPAPC-Ab were found in smoking populations, in patients with hypertension and MI. Anti-oxPAPC-Ab are significantly elevated in patients with hypertension and MI. A synthetic PAPC, after oxidation, was used to detect anti-oxPAPC-Ab, which may greatly enhance the reliability of the assay. The determination of anti-oxPAPC-Ab could serve as an autoimmune marker in the associating diagnosis of cardiovascular disease.

Adult↗
PubMed2005

Age adjustment corrects for apparent differences in erythrocyte sedimentation rate and C-reactive protein values at the onset of seropositive rheumatoid arthritis in younger and older patients.

OBJECTIVE: To evaluate the effect of age adjustment on baseline erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in patients with late-onset rheumatoid arthritis (LORA, age > or = 55 yrs) and younger-onset RA (YORA, age < 55 yrs) in a cohort with early, rheumatoid factor (RF) positive RA that has not received disease modifying antirheumatic drugs (DMARD). METHODS: In an ongoing prospective cohort study of 263 patients with seropositive RA who were enrolled within 14 months of symptom onset, baseline assessments included ESR, CRP, tender and swollen joint counts, and functional status. Westergren ESR determinations were performed in the rheumatologist's office or in a local laboratory using appropriate methods. CRP were performed at the Specialty Laboratories in Santa Monica, CA, using Behring nephelometry. Percentages of patients with greater than the upper limit of normal (ULN) laboratory values using both age-unadjusted and age-adjusted ESR and CRP values were determined. The late-onset and younger-onset RA patients were compared using Wilcoxon rank-sum and chi-square tests. RESULTS: At study entry, both the YORA and LORA patients had comparable symptom duration, disease activity scores, tender and swollen joint counts, and Health Assessment Questionnaire values. RF, CRP, and ESR were significantly higher (p < 0.05) in LORA patients. Although the percentages of patients with age-unadjusted ESR and CRP above ULN were higher in LORA patients, the percentages exceeding the age-adjusted ULN did not differ significantly between the YORA and LORA groups. CONCLUSION: In patients with late-onset and younger-onset RA with similar disease duration and severity, the apparent discrepancy in elevation of both the baseline ESR and CRP disappears after age-adjustment.

Adult↗
PubMed2004

Molecular-based methods for quantifying HIV viral load.

Viral load quantitation has become the major prognostic marker for disease prognosis and outcome of antiretroviral therapy in the treatment of HIV-infected individuals. The three major methodologies for viral load quantitation: the reverse transcriptase-polymerase chain reaction (RT-PCR; Amplicor HIV-1 Monitor Test, Roche Diagnostic Systems, Pleasanton, CA), the nucleic acid sequence-based amplification (NASBA; NucliSens HIV-1 QT Test, Organon Teknika, Bostel, The Netherlands); and a signal amplification methodology termed branchedchain DNA (bDNA) technique (Quantiplex HIV-1 RNA test, Bayer Diagnostics, Emeryville, CA) are briefly reviewed here.

Biomarkers↗
PubMed2003

Image analysis: a novel approach for the quantification of antineutrophil cytoplasmic antibody levels in patients with Wegener's granulomatosis.

Rises in antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) have predictive potential for a relapse of Wegener's granulomatosis (WG). To assess the value of image analysis for monitoring ANCA levels, we measured PR3-ANCA in a cohort of PR3-ANCA positive patients with WG that were prospectively followed in our clinic and compared findings with other techniques. ANCA levels were measured serially by quantitative image analysis, titration in indirect immunofluorescence (IIF), two different directly coated antigen-specific enzyme-linked immunosorbent assays (ELISA), and a capture ELISA using a PR3-specific monoclonal antibody in 16 consecutive WG patients prior to a renal relapse, and in 16 age- and sex-matched patients with inactive WG. The positive predictive value (PPV) of an increase in ANCA titers by image analysis for relapse was 69% (11 of 16). The PPV of an increase in ANCA was 61% (11 of 18) by IIF, 71% (12 of 17) by a commercial direct ELISA, 63% (12 of 19) by in-house direct ELISA, and 75% (12 of 16) by capture ELISA. The negative predictive value (NPV) of the absence of an increase in ANCA titers by image analysis for relapse was 69% (11 of 16). The NPV of the absence of an increase in ANCA was 64% (9 of 14) by IIF, 73% (11 of 15) by a commercial direct ELISA, 63% (9 of 13) by in-house direct ELISA, and 75% (12 of 16) by capture ELISA. In conclusions, quantitative image analysis is a novel technique based on the principle of IIF to quantify ANCA levels in a single dilution in a patient sample. No major differences were observed between image analysis and the other techniques in their capacity to predict relapses of disease activity.

Adult↗
PubMed2003

Anti-idiotypes to oxidized LDL antibodies in intravenous immunoglobulin preparations--possible immunomodulation of atherosclerosis.

OBJECTIVE: The aim of this study was to examine whether intravenous immunoglobulin (IVIg) preparations contain anti-oxLDL and anti-anti-oxLDL antibodies. BACKGROUND: Oxidized low-density lipoprotein (oxLDL) is one of the major players in atherogenesis. IVIg can reduce atherosclerosis in experimental animal models. METHODS: Six commercial IVIg preparations were tested for the presence of anti-oxLDL antibodies by EIA. Inhibition studies were performed with the different IVIg preparations and IgGs purified from a pool of sera from patients with high anti-oxLDL antibody levels. Absorption assays were carried out to evaluate the presence of anti-idiotypes against anti-oxLDL antibodies in IVIg preparations. RESULTS: IVIg preparations tested had various degrees of reactivity towards oxLDL. Absorption experiments suggested that the reactivity was specific because it could be effectively absorbed by oxLDL and not by an irrelevant antigen PPD. The reactivity was smaller than that observed with the IgG from the pool with high anti-oxLDL antibody levels. Inhibition studies with IVIg demonstrated 20-45% inhibition of anti-oxLDL binding to oxLDL, compared to 76% inhibition by the pool with high anti-oxLDL levels. To investigate the presence of anti-idiotypes against anti-oxLDL antibodies within IVIg, F(ab')2 fragments of IVIg IgG were used to absorb IgG F(ab')2 fragments from the pool of sera with high anti-oxLDL levels. The decreased binding to oxLDL of the absorbed supernatants shows that IgG F(ab')2 fragments of the IVIg preparations had high inhibitory capacities ranging from 65 to 90%. CONCLUSIONS: IVIg preparations contain both anti-oxLDL and anti-anti-oxLDL activity. This finding may explain the immunomodulating effect of IVIg in atherosclerosis.

Adjuvants, Immunologic↗
PubMed2003

Titers of antibody to common pathogens: relation to food-based interventions in rural Kenyan schoolchildren.

BACKGROUND: Undernutrition is widely perceived to affect the development of an effective immune system. OBJECTIVE: We used a mini-analysis system to quantitate antibody titers and evaluate the sera of 200 Kenyan schoolchildren for antibodies to Helicobacter pylori [isotypes of immunoglobulins A (IgA), G (IgG), and M (IgM)], hepatitis A virus, rotavirus, tetanus toxoid (IgG), and a panel of recombinant malarial antigens (MSP1(19), MSP2, Ag512, MSP4, and MSP5). DESIGN: Children participated in a school-based feeding intervention with meat, milk, or nonanimal-source foods or in a nonintervention control group. Microvolumes (200 mL) of sera were analyzed at baseline and after 1 y. RESULTS: Nearly all children had elevated titers of antibody to H. pylori, hepatitis A virus, rotavirus, and malaria at the outset, despite a high prevalence of apparent biochemical micronutrient deficiencies and stunting, but many had titers of tetanus toxoid IgG antibodies below the protective concentration. Children with low hemoglobin had a greater proportion of elevated H. pylori IgM antibody titers at baseline, which suggests that current infection with H. pylori may be associated with anemia. Compared with the control subjects, only the group eating meat had a significant increase in H. pylori IgM antibodies during the intervention (P = 0.019). No other group comparisons with the control subjects were statistically significant. The additional finding that the sera of some children showed inadequate tetanus-protective antibodies, despite immunization, suggests that the vaccination program was suboptimal. CONCLUSIONS: A large battery of immune assays can be performed on microvolumes of sera. Furthermore, despite evidence of malnutrition, children do develop significant antibody-mediated responses to common pathogens.

Adolescent↗
PubMed1992

A chronic illness characterized by fatigue, neurologic and immunologic disorders, and active human herpesvirus type 6 infection.

OBJECTIVE: To conduct neurologic, immunologic, and virologic studies in patients with a chronic debilitating illness of acute onset. DESIGN: Cohort study with comparison to matched, healthy control subjects. PATIENTS: We studied 259 patients who sought care in one medical practice; 29% of the patients were regularly bedridden or shut-in. MAIN OUTCOME MEASURES: Detailed medical history, physical examination, conventional hematologic and chemistry testing, magnetic resonance imaging (MRI) studies, lymphocyte phenotyping studies, and assays for active infection of patients' lymphocytes with human herpesvirus type 6 (HHV-6). MAIN RESULTS: Patients had a higher mean (+/- SD) CD4/CD8 T-cell ratio than matched healthy controls (3.16 +/- 1.5 compared with 2.3 +/- 1.0, respectively; P less than 0.003). Magnetic resonance scans of the brain showed punctate, subcortical areas of high signal intensity consistent with edema or demyelination in 78% of patients (95% CI, 72% to 86%) and in 21% of controls (CI, 11% to 36%) (P less than 10(-9)). Primary cell culture of lymphocytes showed active replication of HHV-6 in 79 of 113 patients (70%; CI, 61% to 78%) and in 8 of 40 controls (20%; CI, 9% to 36%) (P less than 10(-8], a finding confirmed by assays using monoclonal antibodies specific for HHV-6 proteins and by polymerase chain reaction assays specific for HHV-6 DNA. CONCLUSIONS: Neurologic symptoms, MRI findings, and lymphocyte phenotyping studies suggest that the patients may have been experiencing a chronic, immunologically mediated inflammatory process of the central nervous system. The active replication of HHV-6 most likely represents reactivation of latent infection, perhaps due to immunologic dysfunction. Our study did not directly address whether HHV-6, a lymphotropic and gliotropic virus, plays a role in producing the symptoms or the immunologic and neurologic dysfunction seen in this illness. Whether the findings in our patients, who came from a relatively small geographic area, will be generalizable to other patients with a similar syndrome remains to be seen.

Adult↗