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Biomedical subjects

D L Weiner

Publications and source records attributed to D L Weiner.

At least 19 recordsLinked to original sources
PubMed2001

Mannan-binding lectin enhances susceptibility to visceral leishmaniasis.

Levels of the serum opsonin mannan-binding lectin (MBL) were directly correlated with the probability of developing visceral leishmaniasis. Monocytes infected with MBL-opsonized Leishmania chagasi promastigotes secreted higher levels of tumor necrosis factor alpha and interleukin-6 than cells infected with nonopsonized parasites. Our findings indicate that MBL can modulate the clinical outcome of infection with L. chagasi and the function of infected macrophages.

Adolescent↗
PubMed2000

Serum amyloid A predicts early mortality in acute coronary syndromes: A TIMI 11A substudy.

OBJECTIVES: We evaluated the ability of serum amyloid A (SAA), alone and in combination with a rapid qualitative assay for cardiac-specific troponin T (cTnT), to predict 14-day mortality in patients with unstable angina or non-Q wave myocardial infarction (NQMI). BACKGROUND: Elevated C-reactive protein (CRP) has been associated with adverse outcomes in unstable coronary syndromes but data regarding its acute phase counterpart, SAA, are conflicting. METHODS: Serum amyloid A measurement and a rapid cTnT assay were performed on blood obtained at enrollment into Thrombolysis in Myocardial Infarction 11A, a dose-ranging trial of enoxaparin for unstable angina and NQMI. RESULTS: Serum amyloid A was higher in patients who died compared with survivors (6.28 vs. 0.75 mg/dL, p = 0.002). Among patients with a negative rapid cTnT, mortality was higher for those in the top quintile of SAA (6.1 vs. 0.7%, p = 0.003). Patients with both an early positive rapid cTnT (< or =10 min until assay positive) and SAA in the fifth quintile had the highest mortality followed by those with either markedly elevated SAA or an early positive rapid cTnT, while patients with both a negative rapid cTnT and SAA in quintiles 1-4 were at very low risk, (9.1 vs. 3.6 vs. 0.7%, p <0.002). CONCLUSIONS: Similar to CRP, baseline elevation of SAA identifies patients hospitalized with unstable angina and NQMI at higher risk for early mortality, even among those with a negative rapid assay for cTnT. These data support further investigation of inflammatory markers used alone and in combination with cardiac troponins for risk assessment in unstable coronary syndromes.

Angina, Unstable↗
PubMed2000

Cardiac toxicity of intravenous terbutaline for the treatment of severe asthma in children: a prospective assessment.

OBJECTIVE: To examine the cardiac toxicity as measured by elevations in serum cardiac troponin T (cTnT) and to compare creatine kinase (CK) and creatine kinase MB (CK-MB) and findings on electrocardiography (ECG) as markers of cardiac toxicity with cTnT during the infusion of intravenous terbutaline for the treatment of severe asthma in children. STUDY DESIGN: Prospective cohort study of patients receiving intravenous terbutaline for severe asthma. RESULTS: Only 3 (10%) of the 29 patients had elevations in cTnT. Each underwent mechanical ventilation for >72 hours, which was the earliest point at which cTnT elevations were identified. Eighteen (62%) patients had an elevation in CK, and 3 had an elevation in CK-MB fraction without an elevated cTnT. Twenty (69%) patients had ECG findings consistent with ischemia, and 19 of these patients had the ischemic findings on their preterbutaline ECG. Elevations in CK and CK-MB and ischemic changes on ECG did not correlate with elevations in cTnT. Both mechanical ventilation (P =.02) and prolonged administration (>72 hours) of intravenous terbutaline (P =. 02) were significantly associated with elevations in cTnT. CONCLUSIONS: We found no clinically significant cardiac toxicity from the use of intravenous terbutaline for severe asthma as measured by serum cTnT elevations.

Adrenergic beta-Agonists↗
PubMed1998

C-reactive protein is a potent predictor of mortality independently of and in combination with troponin T in acute coronary syndromes: a TIMI 11A substudy. Thrombolysis in Myocardial Infarction.

OBJECTIVES: We evaluated C-reactive protein (CRP) alone and in conjunction with a rapid qualitative assay for cardiac-specific troponin T (cTnT) for predicting 14-day mortality in patients with unstable angina or non-Q wave myocardial infarction (NQMI). BACKGROUND: Elevated CRP has been found to correlate with higher risk for cardiac events in patients with coronary disease. METHODS: At enrollment into the Thrombolysis in Myocardial Infarction (TIMI) 11A trial, a dose-ranging trial of enoxaparin for unstable angina and NQMI, serum was obtained for CRP measurement and rapid cTnT assay. RESULTS: Quantitative CRP and rapid cTnT assays were performed in all patients. CRP was higher among patients who died than in survivors (7.2 vs. 13 mg/dl, p = 0.0038). The probability of a positive rapid cTnT assay rose with increasing CRP concentration (p < 0.0001). Among patients with a negative rapid cTnT assay, the mortality rate was higher among patients with CRP > or = 1.55 mg/dl (5.80% vs. 0.36%, p = 0.006). Patients with both an early positive rapid cTnT assay (< or = 10 min until assay positive) and CRP > or = 1.55 mg/dl had the highest mortality, followed by those with either CRP > or = 1.55 mg/dl or an early positive rapid cTnT assay, whereas patients with both a negative rapid cTnT assay and CRP < 1.55 mg/dl were at very low risk (9.10% vs. 4.65% vs. 0.36%, p = 0.0003). CONCLUSIONS: Elevated CRP at presentation in patients with unstable angina or NQMI is correlated with increased 14-day mortality, even in patients with a negative rapid cTnT assay. Quantitative CRP and a rapid cTnT assay provide complementary information for stratifying patients with regard to mortality risk.

Angina, Unstable↗
PubMed1998

Analytical evaluation of particle-enhanced immunonephelometric assays for C-reactive protein, serum amyloid A and mannose-binding protein in human serum.

Against a background of growing interest in more sensitive assays for quantifying various acute phase proteins, we evaluated the performance of recently developed tests for C-reactive protein (CRP), serum amyloid A (SAA) and mannose-binding protein (MBP) on the Behring nephelometer II (BNII). Sample results outside the calibration ranges of 3.5 to 220 mg/L for CRP, 3.3 to 215 mg/L for SAA and 0.09 to 5.6 mg/L for MBP were automatically re-measured at another dilution. The lower limits of detection were 0.01, 0.7 and 0.01 mg/L for CRP, SAA and MBP, respectively. The coefficients of variation (CV) for intra- (n > or = 20) and inter- (n > or = 15) assay precision were < 5.2% and < 8.5%, respectively, for the three proteins at concentrations representing low, normal and high. Linearity for each method was within 5% of the expected values throughout the calibration range. We observed no significant interference from bilirubin (up to 300 mg/L) or haemoglobin (up to 10 g/ L) for the three tests. Method comparison studies performed for CRP and SAA yielded the following results: y (CRP on BNII) = 0.75x (ELISA, Hemagen) -0.25 mg/L (r = 0.981, Sy/x = 2.1 mg/L; y (SAA on BNII) = 1.44x (ELISA, Hemagen) -9.9 mg/L (r = 0.972, Sy/x = 6.9 mg/L), where ELISA is enzyme-linked immunosorbent assay. Reference intervals established in 261 adult blood donors (aged 36.2 +/- 9.0 years) were found to be log-normal with 2.5th, 50th, and 97.5th centiles of < 0.17, 1.00 and 10.1 mg/L for CRP, < 0.84, 2.10 and 9.70 mg/L for SAA; and 0.30, 1.28 and 4.10 mg/L for MBP. We observed no relationship with CRP concentration and age; however, SAA levels increased with age while MBP levels decreased. The BNII provides a simple, rapid and sensitive system for measuring CRP, SAA and MBP in human serum.

Adult↗
PubMed1996

Comparison of early and late treatment with a recombinant endotoxin neutralizing protein in a rat model of Escherichia coli sepsis.

OBJECTIVE: To test the efficacy of a recombinant endotoxin neutralizing protein as compared with saline in rats with Escherichia coli sepsis. DESIGN: Prospective, controlled animal trial. SETTING: Hospital animal research laboratory. SUBJECTS: Male Wistar rats challenged with intraperitoneal E. coli, O18ac K1, and treated 1 hr later with ceftriaxone and gentamicin. INTERVENTIONS: Recombinant endotoxin neutralizing protein, 50 mg/kg, was administered to rats 1, 2, or 3 hrs after E. coli challenge; saline was administered to control animals. MEASUREMENTS AND MAIN RESULTS: Quantitative bacteremia, 1 hr after challenge and before antibiotic administration, was not significantly different between treatment groups (range geometric mean 451 to 621 colony-forming units [cfu]/mL). The endotoxin concentration, measured immediately before recombinant endotoxin neutralizing protein administration, was significantly higher in animals sampled and treated at 2 hrs (geometric mean 260 EU/mL; 95% confidence interval 140 to 480 EU/mL), or 3 hrs (geometric mean 697 EU/mL; 95% confidence interval 307 to 1585 EU/mL) after E. coli challenge, compared with animals sampled and treated at 1 hr (geometric mean 17 EU/mL; 95% confidence interval 7 to 69 EU/ mL). Survival rate was significantly greater in rats treated with recombinant endotoxin neutralizing protein at 1 hr (23/27; p < .001) or 2 hrs (8/30; p < .01) after E. coli challenge than in controls (1/32). CONCLUSION: Administration of recombinant endotoxin neutralizing protein delayed up to 2 hrs after challenge with E. coli improves survival in antibiotic-treated rats with Gram-negative sepsis.

Animals↗
PubMed1995

Failure of prophylactic and therapeutic use of a murine anti-tumor necrosis factor monoclonal antibody in Escherichia coli sepsis in the rabbit.

OBJECTIVE: To determine the efficacy of a murine anti-tumor necrosis factor (TNF) monoclonal antibody in the treatment of Escherichia coli peritonitis and sepsis in the rabbit. DESIGN: Prospective, paired, randomized, blinded, controlled animal trial. SETTING: Animal research laboratory. SUBJECTS: Male New Zealand white rabbits. INTERVENTIONS: Anesthetized rabbits were cannulated with indwelling femoral arterial and venous catheters. Peritonitis and sepsis were induced by intraperitoneal challenge using live E. coli O18ac bacteria. All animals were treated with gentamicin and ceftriaxone 1 hr after challenge. One group (prophylaxis experiment) consisting of ten rabbit pairs (the prophylaxis group), was treated with either murine anti-TNF monoclonal antibody or an equivalent volume of 5% albumin 3 hrs before E. coli challenge. A second group (therapeutic experiment) of 17 rabbit pairs, the treatment group, was also treated with murine anti-TNF monoclonal antibody or albumin control 1 hr after E. coli challenge. MEASUREMENTS AND MAIN RESULTS: All animals were bacteremic 1 hr after challenge. Physiologic measures of sepsis (heart rate, mean arterial pressure, serum bicarbonate, and arterial pH) did not differ between control, prophylaxis, and treatment groups. Peak serum TNF concentration was significantly (p < .01) lower in animals receiving anti-TNF monoclonal antibody, in both the prophylaxis and treatment groups, than in control animals. The survival rate was not improved significantly in either the prophylaxis or treatment group. CONCLUSIONS: Prophylactic and therapeutic use of anti-TNF monoclonal antibody in a rabbit model of E. coli peritonitis and sepsis significantly lowers TNF concentrations but does not ameliorate the physiologic effects of sepsis and does not significantly improve survival.

Animals↗
PubMed1986

NONLIN84/PCNONLIN: software for the statistical analysis of nonlinear models.

A new software package, NONLIN84, has been developed for the analysis of general nonlinear models including pharmacokinetic models. NONLIN84 is easier to use than the older NONLIN77, and can handle a wider class of estimation problems, such as maximum likelihood estimation involving iterative reweighting. Two large libraries of pharmacokinetic models are distributed with NONLIN84 and can be accessed by simply specifying a model number. A companion program, PCNONLIN, runs on DOS based microcomputers and retains most of the features of NONLIN84.

Humans↗
PubMed1985

Amino acids in amniotic fluid in the second trimester of gestation.

The concentrations of amino acids in amniotic fluid have been used in the prenatal diagnosis of several inherited metabolic disorders. However, previous studies have usually examined only a small number of control amniotic fluid samples. We have, therefore, measured the amino acids in amniotic fluid samples from 183 normal pregnancies between the 13th and the 23rd wk gestation of women ranging in age from 17 to 43 yr. The concentrations of Ala, Lys, Val, Glu, Pro, Thr, and Gly, in descending order, accounted for about 70% of the amino acids in amniotic fluids. A negative correlation with gestational age (-0.34 to -0.24) was found for Leu, Val, Ile, Phe, Lys, Ala, Asp, Tyr, Glu, and Pro, with Leu showing the greatest rate of change. The concentration of Gln increased slightly (r = 0.18), whereas the other amino acids did not change significantly during this period. Statistically significant positive correlations, at all gestational ages, were observed among Val, Leu, and Ile. These branched-chain amino acids also correlated positively with Phe, Lys, Asp, Thr, Ser, Glu, Pro, Gly, Ala, and Tyr, and the amino acids within this group correlated with each other. Additionally, strong positive correlations were observed between Phe and Tyr and between Gly and Ser. No significant correlations were found between any of the amino acids and maternal age or fetal sex. Significant positive correlations between amino acids may be indicative of common transport or degradative pathways and suggest that maintenance of specific relative concentrations in amniotic fluid may be essential for normal fetal development.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Method of analysis of the new cardiotonic agent, MDL 19,205, in plasma and urine and its application in a dog pharmacokinetic study.

A high-performance liquid chromatographic method has been developed for the analysis of plasma and urine concentrations of a new cardiotonic agent, MDL 19,205 (I). This procedure was utilized to study the pharmacokinetics of I in beagle dogs. The results of the dog study show that the compound is completely and rapidly absorbed. Plasma concentrations fell in a monoexponential manner with a half-life of about 1.3 h which was unaffected by dose in the range 3-30 mg/kg. Urinary excretion of unchanged I accounts for about one-half of the dose and is essentially complete in 24-48 h.

Administration, Oral↗
PubMed1982

A simulation study of parameter estimation in the one and two compartment models.

Few attempts have been made to examine the statistical problems that the user of compartmental models must face. Some properties of the estimators of parameters for one and two compartmental models based on nonlinear estimation were studied through simulation. Of particular interest were the effect of the experimental design and the effect of different error structures on the empirical sampling distribution for the estimators. For the one compartment model it was found that nonlinear estimation yielded essentially unbiased estimators that were normally distributed unless the random error for the model was large. In the two compartment model simulations, bias appeared in the estimators to the extent that bimodal sampling distributions of the estimators were observed as the random error for the model was increased.

Humans↗