Biomedical subjects

D H Atchley

Publications and source records attributed to D H Atchley.

4 recordsLinked to original sources

PubMed2002

Oxidized LDL-anti-oxidized LDL immune complexes and diabetic nephropathy.

AIMS/HYPOTHESIS: Oxidized LDL is immunogenic and immune complexes formed by oxidized LDL and corresponding antibodies are pro-atherogenic and pro-inflammatory. Considering that macroalbuminuria is a risk factor for coronary heart disease and that common pathogenic factors for atherosclerosis and glomerulosclerosis exist, our aim was to determine whether the amount and/or characteristics of oxidized LDL- anti-oxidized LDL complexes correlated with the degree of albuminuria in patients with Type I (insulin-dependent) diabetes mellitus. METHODS: We studied 33 macroalbuminuric patients (albumin excretion rate >300 mg/24 h) and 29 microalbuminuric patients (albumin excretion rate >or=30 mg/24 h and <or=300 mg/24 h) who were matched for age, sex and HbA(1C) concentrations with 43 patients with normal albuminuria. In all patients we isolated and characterized oxidized LDL-anti-oxidized LDL complexes. A subgroup of 47 patients (22 with normal albuminuria, 11 with microalbuminuria, and 14 with macroalbuminuria) was randomly selected from the larger group for characterization of the antibody moiety of oxidized LDL immune complexes. RESULTS: The concentrations of oxidized LDL immune complexes were increased in patients with macroalbuminuria (total cholesterol in immune complexes isolated from patients with macroalbuminuria was 272+/-20 vs 204+/-18 micro g/ml in patients with normoalbuminuria, p<0.03). Also, the Kd of oxLDL antibodies isolated from the immune complexes was lower in patients with abnormal albuminuria than in patients with normoalbuminuria (0.86+/-0.1x10(-8) vs 1.13+/-0.1x10(-8) mol/l, p<0.05). CONCLUSION/INTERPRETATION: The data indicate that high concentrations of oxidized LDL-anti-oxidized LDL complexes, particularly when formed with antibodies of higher avidity, are associated with abnormal proteinuria.

Adult↗

PubMed2001

Antibody response to DT-GM, a novel fusion toxin consisting of a truncated diphtheria toxin (DT) linked to human granulocyte-macrophage colony stimulating factor (GM), during a phase I trial of patients with relapsed or refractory acute myeloid leukemia.

We are conducting a Phase I trial of a fusion toxin (DT-GM) for the treatment of relapsed or refractory acute myeloid leukemia (AML). The fusion toxin consists of a truncated diphtheria toxin (DT) linked to human granulocyte-macrophage colony stimulating factor (GM). Prior to beginning the Phase I trial, our first goal was to determine whether healthy controls and adult AML patients had preexisting antibodies able to inhibit DT-GM. Sera from 5 of the 9 controls completely neutralized DT-GM by an in vitro bioassay to assess the inhibition of DT-GM. Sera from 43 patients with AML were tested by bioassay and a specific enzymoimmunoassay (EIA) for anti-DT-GM antibodies. Forty-two of 43 samples were positive by EIA, and 5 patients (11.6%) showed complete neutralization of DT-GM in the bioassay. Anti-DT-GM concentrations were significantly higher in samples demonstrating neutralization than in samples demonstrating no neutralization (P = 0.003). In the Phase I trial of DT-GM prior to therapy, none of 28 patients exhibited neutralization by bioassay, but 89% were positive by EIA. After the first course of DT-GM, 23% developed neutralizing antibodies by the bioassay, and 64% of patients exhibited an increase in their anti-DT-GM antibody concentrations by EIA. Further studies are needed to determine the clinical impact of the anti-DT-GM antibodies and whether the neutralization bioassay can be replaced by our EIA.

Adult↗

PubMed1998

Prevalence of fecal shedding of Salmonella organisms among captive green iguanas and potential public health implications.

OBJECTIVE: To determine prevalence of fecal shedding of Salmonella organisms among captive green iguanas (Iguana iguana). DESIGN: Cohort study. ANIMALS: 12 captive green iguanas. PROCEDURE: Iguanas were isolated in an environmental chamber, and fecal samples were collected weekly for 10 consecutive weeks. Samples were incubated aerobically in tetrathionate broth for 18 to 24 hours. Aliquots were then transferred to Hektoen and Salmonella-Shigella agar plates and incubated for an additional 18 to 24 hours. Isolated colonies were subcultured on nutrient agar slants, and Salmonella isolates were serogrouped and serotyped. RESULTS: All 12 iguanas were found to be shedding Salmonella organisms at least once during the study, and multiple serotypes were isolated from 7 of the 12. Salmonella organisms were isolated from 88 of 106 (83%) fecal samples; 21 samples contained multiple Salmonella serotypes. Overall, 11 Salmonella serotypes were identified. In 74 of 100 instances, when a particular Salmonella serotype was isolated from an individual iguana, the same serotype was also isolated from a subsequent fecal sample from that iguana. CLINICAL IMPLICATIONS: Results suggested that most iguanas have a stable mixture of Salmonella serotypes in their intestinal tracts and intermittently or continuously shed Salmonella organisms in their feces. Veterinarians should advise their clients on precautions for reducing the risk of acquiring these organisms from their pets. Public health officials trying to determine whether an iguana is the source of a specific Salmonella serotype that caused infection in human patients should submit at least 3 fecal samples collected from the iguana 1 week apart for bacterial culture.

Animals↗

PubMedDate not supplied

Ascorbic acid clearance in diabetic nephropathy.

The incidence of cardiovascular disease is increased in diabetic nephropathy. Increased oxidative stress in diabetes is believed to play an important role in the pathogenesis of atherosclerosis in diabetes. Since antioxidant vitamins, such as ascorbic acid, often are reduced in diabetes, we hypothesized that the renal clearance of ascorbic acid is increased in patients with diabetic nephropathy. Thirty-seven subjects with diabetic nephropathy were studies: 18 had microalbuminuria (30-300 mg/day albuminuria); the remainder had clinical nephropathy (> 300 mg/day albuminuria). Indices of glycemic control (glucose, hemoglobin A1C) and renal function (albuminuria and creatinine clearance) were measured in addition to serum and urinary ascorbic acid levels. Results showed that subjects with clinical nephropathy had lower mean plasma ascorbic acid (p=0.0009) and higher renal clearance of ascorbic acid (p=0.005) than those with microalbuminuria. Bivariate analysis revealed an inverse correlation between creatinine clearance and AA clearance (r=-0.42, p=0.009). There was a significant linear association between the quantity of albuminuria and ascorbic acid clearance (r=0.49, p=0.002). Thus, patients with diabetic nephropathy have reduced ascorbic acid levels due to increased ascorbic acid clearance. The decrease in antioxidant defense that arises from the low levels of vitamin C may contribute to the increased cardiovascular morbidity and mortality observed in this population.

Adult↗