Bone microstructure analyses in ontogenetic series of Mesosaurus tenuidens from the early Permian of Brazil.

Osteohistological evidence is widely used to infer paleobiological traits of fossil vertebrates, such as ontogeny and growth rates. Mesosaurs, an enigmatic group of aquatic reptiles from the early Permian, are the most well-known Paleozoic amniotes from Africa and South America. Their fossils are abundant in South America, ranging from the central-west region of Brazil to the southernmost areas, as well as parts of Paraguay and Uruguay.

Replacement tooth in mesosaurs and new data on dental microanatomy and microstructure.

The Permian mesosaurs are well known for being the earliest amniotes to exhibit adaptations for living in a marine environment (Irati-Whitehill Sea). In addition to their set of skeletal features associated with aquatic dwelling life, their dentition includes important characteristics related to feeding in this habitat, which is described in this work, based on the analysis of mesosaur specimens from the Lower Permian Irati Formation of Brazil. Mesosaurs have several slender, conical teeth bordered by enamel apicobasal ridges, a feature predominantly found in aquatic amniotes.

A new Xenacanthiformes shark (Chondrichthyes, Elasmobranchii) from the Late Paleozoic Rio do Rasto Formation (Paraná Basin), Southern Brazil.

The Brazilian records on Xenacanthiformes include teeth and cephalic spines from the Parnaíba, Amazonas and Paraná basins. This work describes a new species of Xenacanthidae, collected in an outcrop of Serrinha Member of Rio do Rasto Formation (Wordian to Wuchiapingian), Paraná Basin, municipality of Jacarezinho, State of Paraná. The teeth of the new species are two or three-cuspidated and the aboral surface show a smooth concavity and one rounded basal tubercle.

Implications of elevated cardiac troponin T in ambulatory patients with heart failure: a prospective analysis.

Background: Elevated concentrations of cardiac troponin T (TnT) have been reported in patients hospitalized for decompensated heart failure (HF). We assessed whether elevated TnT levels are associated with the severity, etiology, and prognosis of HF in stable, ambulatory patients.

Methods: From 1998-1999, we prospectively collected data from 136 ambulatory patients with HF, New York Heart Association functional class II to IV, ejection fraction < or =35%, and no recent unstable angina, myocardial infarction, surgery, or coronary revascularization.

Multicenter evaluation of the Roche NT-proBNP assay and comparison to the Biosite Triage BNP assay.

Background: Brain natriuretic peptides (BNPs) are useful in the assessment of heart failure, left ventricular dysfunction, and acute coronary syndromes.

Methods: We performed a multicenter evaluation of the automated Roche NT-proBNP assay and compared its performance to the Biosite Triage BNP assay.

Results: The N-terminal (1-76) pro brain natriuretic peptide (NT-proBNP) method is precise (CV View Article and Find Full Text PDF

pH effects on measurements of ionized calcium and ionized magnesium in blood.

Context: It is well known that the concentration of ionized calcium in blood is affected by the pH of the specimen, since hydrogen ions compete with calcium for binding sites on albumin and other proteins. However, the relationship between pH and ionized magnesium concentration is not as well characterized.

Objective: To determine the effects of pH on ionized magnesium concentration over a wide range of pH values in serum or plasma.

Urinary interleukin-8 with asymptomatic bacteriuria in pregnancy.

Objective: To evaluate urinary interleukin-8 (IL-8), an inflammatory cytokine, as a screening method for detecting asymptomatic bacteriuria in pregnancy.

Methods: Clean-catch urine samples from 200 pregnant women undergoing screening for asymptomatic bacteriuria were evaluated by urine culture, urine dipstick analysis, and measurement of IL-8. Interleukin-8 levels were measured by a chemiluminescent immunoassay (Immulite IL-8, Diagnostic Products Corp.

Comparison of cardiac troponin T versus creatine kinase-MB for risk stratification in a chest pain evaluation unit.

We evaluated cardiac troponin T (cTnT) and creatine kinase-MB (CK-MB) for risk stratification of chest pain unit (CPU) patients. We studied 383 consecutive patients with chest pain assigned to our CPU by emergency department physicians. At baseline all had normal or nondiagnostic electrocardiograms, no high-risk clinical features, and negative CK/CK-MB.

Cardiac troponin T levels in umbilical cord blood.

Objective: We sought to determine cardiac troponin T concentrations in umbilical cord plasma from normal and complicated pregnancies.

Study Design: At the time of delivery, umbilical cord arterial and venous samples were collected from 209 neonates, and cardiac troponin T levels were measured by immunoassay. Comparisons of clinical factors were made between neonates with normal and elevated cardiac troponin T levels.

Laboratory tests in evaluation of acute febrile illness in pediatric emergency room patients.

The rising costs of health care and the movement for health care reform have focused attention on methods of cost containment. Of routine laboratory and radiologic procedures, complete blood cell count (CBC) and determination of serum electrolyte values rank as high as 2nd and 9th in overall cost. We retrospectively studied use of the clinical laboratory to aid diagnosis of an acute infectious event in a pediatric emergency department population.

Pneumatic transport exacerbates interference of room air contamination in blood gas samples.

Objective: To characterize and control the potential interference to P(O2) determinations when blood contaminated with air is sent via a pneumatic tube system (PTS).

Design: Both tonometered blood at P(O2)s of 65, 75, 142, and 339 mm Hg and arterial blood gas samples from patients with baseline P(O2)s from 70 to 400 mm Hg were analyzed for P(O2) to determine possible effects of air contamination from PTS transport.

Setting: A large teaching hospital in which a variety of personnel routinely send samples to the laboratory by PTS transport.

Ultrafiltration discrepancies in recovery of myoglobin from urine.

We investigated the efficiency, accuracy, and reliability of the ultrafiltration/dipstick methodology commonly used to diagnose myoglobinuria. Twenty-five myoglobin-containing urine specimens were filtered by centrifugation for 15 min at 1500g through a Centricon-30 membrane filter. Both the original specimen and filtrate were assayed for myoglobin.

Adaptation of a quantitative immunoassay for urine myoglobin. Predictor in detecting renal dysfunction.

Myoglobinuria, subsequent to rhabdomyolysis, may cause acute renal failure. For this reason, many qualitative and quantitative tests have been developed for the detection of myoglobin in urine. The authors describe the adaptation and optimization of the Stratus II serum myoglobin immunoassay to quantify urine myoglobin.

Evaluation of the YSI 2300 glucose analyzer: algorithm-corrected results are accurate and specific.

Objectives: To insure commutability (equivalence) between whole blood and plasma glucose values and to assess potential interferences in glucose oxidase methods.

Design And Methods: We compared plasma glucose results by the Ektachem 700 analyzer to glucose results on whole blood by the Nova Stat Profile 6, and by the YSI 2300, both without hematocrit correction (YSIunc) and with two different hematocrit (Hct) corrections. The two correction methods were: (a) whole blood results multiplied by 1.

Intracellular magnesium content of mononuclear blood cells and granulocytes isolated from leukemic, infected, and granulocyte colony-stimulating factor-treated patients.

The intracellular magnesium (Mg) concentration of granulocytes and mononuclear blood cells (MBCs) was determined in cells isolated from patients with several disorders. The mean (+/-SD) Mg content of MBCs isolated from patients diagnosed with lymphocytic leukemia, myelocytic leukemia, or infection; from patients treated with granulocyte colony-stimulating factor (G-CSF); and from healthy volunteers (control group) was 2.3 (+/-0.

Artifactual hypoglycemia associated with hematopoietic cytokines.

We observed apparent hypoglycemia in seven patients manifesting granulocytosis associated with hematopoietic cytokine treatment or with a leukemoid reaction. All seven patients had confounding preanalytic conditions of specimen transport delay and lack of antiglycolytic agents. Cytokine-stimulated leukocytes may cause artifactual hypoglycemia by consuming glucose in vitro, possibly leading to unnecessary diagnostic evaluation.

Stability of plasma lactate in vitro in the presence of antiglycolytic agents.

The use of plasma lactate to assess metabolic or circulatory impairment requires definition of critical preanalytical and analytical parameters. Stability has been documented for only 15 min after acquisition when samples were collected with fluoride and transported on ice. We examined time elapsed before analysis, storage temperature, and the antiglycolytic agent used to define preanalytical conditions.

Effect of coffee on cholesterol and apolipoproteins, corroborated by caffeine levels.

The possibility that coffee may increase cholesterol levels has created uncertainty among physicians. The confusion arose from cross-sectional studies, in which female coffee drinkers appeared to show a positive association more frequently than men. To clarify this relationship, we designed an intervention trial to reduce caffeine and coffee intake sequentially while measuring total cholesterol and the apolipoprotein A-I and B levels.

Reflotron cholesterol measurement evaluated as a screening technique.

We evaluated the analytical performance of Boehringer Mannheim Diagnostics' "Reflotron" analyzer for the measurement of cholesterol. Coefficients of variation (CVs) for whole-blood cholesterol were: within-day 2.0% and 2.

Digoxin-like immunoreactivity eliminated from serum by centrifugal ultrafiltration before fluorescence polarization immunoassay of digoxin.

Digoxin determined in the Abbott "TDx" by fluorescence polarization immunoassay by the manufacturer's recommended method involving precipitation of protein with 5-sulfosalicylic acid (SSA) is subject to interference from endogenous compounds having digoxin-like immunoreactivity. Guided by the work of Graves et al. (Clin Chem 1986;32:1506-9), we eliminated interference caused by digoxin-like immunoreactivity by substituting ultrafiltration for precipitation with SSA to remove protein.

Comparison of pyridoxal phosphate-supplemented reagent kits for alanine aminotransferase using centrifugal analysis.

The addition of pyridoxal-5-phosphate for assay of alanine aminotransferase has been recommended. The referral methods are inconvenient for high volume instrumentation due to use of multiple reagents and blanks. We adapted a well-documented method to the centrifugal analyzer as a reference for adaptation of two kit methods.

Breast milk iodide: reassessment in the 1980s.

In addition to iodized salt, the American diet is inadvertently supplemented with iodine from other foods, such as bread and cow's milk. The iodine content of breast milk has not been assessed recently in this country. Sixty-one samples of breast milk from 37 women were analyzed for iodide content using an iodide-selective electrode method.