Rat gonadotropin-releasing hormone receptor expressed in insect cells induces activation of adenylyl cyclase

The diagnostic usefulness of measuring plasma D-dimers using the ELISA method and the latex agglutination test has been prospectively evaluated in 117 patients hospitalized for suspicion of acute venous thrombo-embolism (AVTE): pulmonary embolism was suspected in 80 patients and the remaining 37 had a suspicion of deep vein thrombosis of the lower limbs. The diagnosis of AVTE was confirmed in 50% of the patients, all of whom underwent gold standard invasive investigation i.e. pulmonary angiography and/or contrast venography. The sensitivity, specificity, negative predictive value and positive predictive value of a D-dimers plasma concentration exceeding 500 ng/ml for the diagnosis of AVTE were respectively 98, 58, 97 and 70% when using the ELISA method, and 86, 71, 84 and 75% when using the latex assay. In 47 patients whose lung scans yielded abnormalities of indeterminate probability of pulmonary embolism, the sensitivity of the ELISA method was very high (94%), but that of latex assay was low (67%). Our results demonstrate that measuring the plasma D-dimers by the latex assay should not be used in the diagnosis of AVTE. On the other hand, the ELISA method might be of great interest in the diagnostic strategy of AVTE, as a normal concentration of D-dimers rules out almost definitely the diagnosis of AVTE, and hence, spares from performing invasive investigations.     

Evaluation of the portable blood analyser i-STAT]

The purpose of this study was to compare the results of horse blood examinations on a portable blood analysis system, i-STAT SDI, with conventional laboratory equipment and to verify the accuracy and precision. The precision within run was high and the coefficients of variation ranged from 0 to 3.85%. The comparative analysis of patient samples with routine methods showed a very strong positive correlation with correlation coefficients above 0.96 for blood gases, pH, glucose, urea, hemoglobin, hematocrit, sodium and potassium, with the exception of chloride where it was 0.867. The i-STAT system provides a quick and accurate stable-side evaluation of laboratory data in critically ill horses and emergency situations.     

Radiofrequency tissue ablation: increased lesion diameter with a perfusion electrode

RATIONALE AND OBJECTIVES: We sought to induce large zones of coagulation necrosis using radiofrequency (RF) with perfusion electrodes and to define optimal parameters for this system. METHODS: We developed RF electrodes with internal cannulas to enable tip perfusion. Lesions were created with monopolar RF in ex vivo and in vivo liver and muscle tissue with and without perfusion of the electrode tip using 0 degree C saline. In separate experiments, wattage, current, procedure duration, tip exposure, and perfused tip temperatures were studied. RESULTS: In ex vivo liver tissue, a maximum lesion diameter of 3.1 cm without charring occurred with perfusion at 12 min and 50 W. In in vivo liver tissue with perfusion (tip temperature = 25-35 degrees C) and a 3-cm tip exposure, 80 W were deposited in muscle tissue and 65 W in liver tissue for 12 min without inducing charring. Lesion diameters were 4.5 cm and 2.4 cm, respectively. By comparison, without perfusion a maximum of 20 W could be deposited into either tissue type, resulting in 1.8-cm muscle lesions and 1.2-cm liver lesions. Tip temperatures between 45 degrees C and 55 degrees C resulted in charring. Smaller but predictable lesion diameters were created with a lower power, a shorter tip exposure, or both. Of all the parameters, diameter correlated best with the current applied. CONCLUSION: Perfusion of RF electrodes with chilled saline allows for increased power deposition without tissue charring, increasing the volume of coagulation necrosis created with a single electrode insertion. Perfusion electrodes therefore might decrease the number of probe insertions required for percutaneous tumor ablation therapy or allow for the treatment of larger lesions.     

Spotted fever group rickettsiae in southern Africa--a review and current concepts

Until recently our understanding of spotted fever group (SFG) rickettsioses in southern Africa was based on research carried out in the 1930s and 1940s. In the last decade there have been considerable advances in the techniques available to study rickettsias and the application of these in southern Africa has greatly increased our knowledge of the organisms in the region and the epidemiology of diseases they cause. In this review we describe the new advances used to study rickettsias and the current data available on SFG rickettsioses in the region.     

Factors influencing the choice of buffer in background electrolytes for indirect detection of fast anions by capillary electrophoresis

The suitability of relatively slow (low absolute value of mobility) coanionic buffers in background electrolytes (BGEs) for indirect photometric detection of anions by capillary electrophoresis was investigated. As a model system, 2-(cyclohexylamino)ethanesulfonic acid (CHES) was used to buffer the indirect detection electrolyte of sodium chromate. CHES (PKa 9.55) is a zwitterionic molecule carrying a net negative charge depending on the pH (effective charge -0.5 at pH = pKa). Within its useful pH buffering range CHES acted as a competing probe coanion. System peaks were induced which had deleterious effects on the detection sensitivity of slow to medium mobility anions. The mobility of the system peak was determined by the effective mobility of CHES, both of which increased with increasing pH. The peaks of analytes that migrated near or on the system peak were distorted and lost all quantitative properties. Analytes that migrated after the system peak either were not detected or reversed their responses. Analytes that migrated well before the system peak were unaffected. Consequently, the suitability of slow coanionic buffers is limited either to (i) fast anions or, (ii) a pH range much below the PKa, where the buffering capacity is not optimal.     

Cocaine and metabolites in amniotic fluid may prolong fetal drug exposure

OBJECTIVE: Cocaine and metabolites can be found in the amniotic fluid after maternal use, presumably as a result of fetal urination. The fetus may be repeatedly exposed to the effects of these drugs through contact with amniotic fluid that contains these substances. The purpose of this study was to determine whether the naive fetal lamb generates detectable fetal blood levels of cocaine and metabolites when cocaine is placed directly into the amniotic fluid and, if so, whether fetal swallowing accounts for these findings. STUDY DESIGN: Six pregnant ewes with singleton fetuses of 120 to 125 days' gestation were chronically catheterized for daily sampling of cocaine and metabolite levels in maternal venous plasma, fetal venous plasma, and amniotic fluid over a 7-day period. Esophageal ligation was performed in three additional animals similarly instrumented to evaluate the role of fetal swallowing in the distribution of amniotic fluid cocaine and its metabolites. In each case, at the time of surgery, an Alzet osmotic pump delivering cocaine at 0.5 mg/kg estimated fetal weight per hour into the amniotic fluid was secured to the fetal back. Cocaine and metabolites (benzoylecgonine, ecgonine methyl ester, and norcocaine) were measured daily in material and fetal plasma, amniotic fluid, and meconium by solid-phase extraction and derivatization and quantified by high-performance gas chromatographic techniques. RESULTS: The concentrations of ecgonine methyl ester were highest in the amniotic fluid followed by cocaine and benzoylecgonine. In the normal and esophagus-ligated groups, cocaine, benzoylecgonine, and norcocaine were found in fetal plasma in concentrations of approximately 3% that of amniotic fluid. Ecgonine methyl ester was not detected in fetal plasma from either group. Meconium samples from sheep with and without esophageal ligation demonstrated high levels of norcocaine. CONCLUSION: We conclude that cocaine and metabolites in amniotic fluid enter the fetal circulation to produce detectable plasma levels through routes other than swallowing. Moreover, the results of meconium analyses in the two groups of fetuses suggest that fetal swallowing is not the primary mechanism by which cocaine and metabolites enter the intestine.     

SLE myocarditis. Detection by Ga-67 citrate scintigraphy

Cardiac uptake of Ga-67 in myocarditis has been described in association with a number of disease entities. However, there are no reports in the current literature describing Ga-67 uptake in myocarditis due to systemic lupus erythematosus, a disease that often involves the heart. The authors present the case of a patient with a long history of systemic lupus erythematosus in whom new ECG changes and left ventricular wall motion abnormality developed, and who demonstrated significant global myocardial uptake on Ga-67 scintigraphy. Other etiologies including myocardial infarction, epicardial coronary disease, pericarditis, endocarditis, dilated cardiomyopathy, and viral infection were excluded during extensive work-up.     

A comparison of cotton dust sampling techniques

The standard high volume sampler, multistage cascade impactor, and modified vertical elutriators were evaluated for total cotton dust sampling. The effects of changes in performance parameters is reported. Mass median dust diameter found in four textile operations for several cotton grades are reported.