Frequency Analysis of Ventricular Fibrillation and Resuscitation Success

SUMMARY In 56 patients, frequency analysis of the electrocardiogramof ventricular fibrillation exhibited power spectra with a distinctdominant frequency. The greatest success for resuscitation fromventricular fibrillation is recorded when ventricular fibrillationdevelops after the patient comes under coronary care. Of the41 patients in whom the onset and first 8 s of ventricular fibrillationwere artefact-free the mean dominant frequency of primary ventricularfibrillation (no cardiogenic shock or cardiac failure) in 21patients was 6.2±0.2 Hz, significantly higher than themean dominant frequency of the first 8 s of secondary ventricularfibrillation (cardiogenic shock or heart failure) (4.0±0.2Hz, 20 patients, p =0.0001). In these patients the peak-to-troughamplitude (ECG) of the first 8 s of ventricular fibrillationwas similar in both primary and secondary ventricular fibrillationas was the mean duration of ventricular fibrillation prior tothe first DC shock. There was a significantly lower successrate for resuscitation from secondary ventricular fibrillation(6 of 20 patients) compared with resuscitation from primaryventricular fibrillation (18 of 21 patients, x² 17.8, p=0.001).Of the remaining 15 patients who were collapsed between 3 and20 min before the arrival of the mobile coronary care unit,the dominant frequency of the first 8 s of ventricular fibrillationfell with increased duration of collapse (from 5.5 Hz at 3 minto a mean of 2.1 Hz at 20 min). Four of these 15 patients whosurvived the initial arrest had a mean dominant frequency of5.2±0.3 Hz, which was significantly higher than the meandominant frequency (3.1±0.3 Hz, p<0.01) of the 11patients who were not resuscitated. This study shows that low frequency ventricular fibrillationis indicative of a poor chance of successful resuscitation.Alteration of the frequency may increase resuscitation success.     

Detection of antibodies to Trypanosoma cruzi among blood donors in the southwestern and western United States. II. Evaluation of a supplemental enzyme immunoassay and radioimmunoprecipitation assay for confirmation of seroreactivity

BACKGROUND: Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, is endemic to Latin America and may be transmitted in the United States via blood donated by infected immigrants. Blood- borne pathogens such as T. cruzi require supplemental testing for confirmation of seroreactivity. STUDY DESIGN AND METHODS: A study was undertaken to determine an optimal scheme for confirmation of seroreactivity in repeatedly reactive samples identified by the Chagas antibody enzyme immunoassay (EIA). The procedure for initial confirmation involves three purified antigens coated onto three separate polystyrene beads and uses an EIA format. If the sample is reactive with two of three or three of three antigens, it is confirmed as seroreactive. If none or one of three beads is reactive, the sample is indeterminate and subjected to a radioimmunoprecipitation assay (RIPA). The RIPA must demonstrate characteristic bands at 32, 34, and 90 kDa. RESULTS: When tested with sera from persons with potentially cross-reactive diseases (n = 39) or against a presumed negative population from southeast Wisconsin (n = 289), the confirmatory EIA had a specificity of 100 percent. Sensitivity was 100 percent (28/28) with xenodiagnosis-positive sera and 97.6 percent (80/82) with chagasic sera from Latin America. The RIPA showed a specificity of 100 percent in EIA- nonreactive samples (n = 100) and a sensitivity of 100 percent with both xenodiagnosis-positive (28/28) and chagasic (82/82) sera. CONCLUSION: The confirmatory EIA and the RIPA together provide a highly specific and sensitive means of confirming seroreactivity for antibodies to T. cruzi.     

Intraosseous carcinoma of the jaws—A clinicopathologic review. Part I: Metastatic and salivary‐type carcinomas

This is the first part of a 3‐part comprehensive review of intraosseous carcinoma of the jaws. We have outlined 4 groups of intraosseous carcinoma of the jaws (metastatic, salivary‐type, odontogenic, and primary intraosseous carcinoma), emphasizing the need for accurate diagnosis and the problems associated with changing classification systems, standardization of diagnostic criteria and nomenclature, and the accuracy of existing literature. In this first part, the features of metastatic and the very rare salivary‐type carcinomas of the jaws are examined with particular emphasis on histologic and immunohistochemical characteristics, diagnostic difficulties, and uncertainties. © 2012 Wiley Periodicals, Inc. Head Neck, 2012     

Effects of recombinant human granulocyte-macrophage colony-stimulating factor on intracellular pH in mature granulocytes

We studied the effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh) on the internal pH of granulocytes using the fluorescent probe BCECF. GM-CSFrh did not directly alter the resting pH of granulocytes isolated from the peripheral blood; however, when the cells were preincubated for 90 minutes with the growth factor and then activated with the chemotactic peptide N-formyl met leu phe (fMLP), they exhibited both an acceleration in the initial rate of acidification and a marked delay in realkalinization. The kinetic changes both in initial acidification and in subsequent realkalinization induced by GM-CSFrh priming were not prevented by protein synthesis inhibitors and were observed in granulocytes harvested from patients with both sex-linked and autosomal recessive chronic granulomatous disease (CGD). By directly quantitating H+ ion secretion, by monitoring the effects of sodium repletion on intracellular pH, and through use of the sodium channel inhibitors amiloride and dimethyl amiloride and the Na+/K+-ATPase inhibitor ouabain, we showed that the altered kinetics of intracellular acidification and alkalinization following fMLP stimulation of GM-CSFrh- primed granulocytes could not be accounted for by changes in transmembrane proton exportation regulated by the Na+/H+ antiport channel. Although the initial acidification following fMLP was abrogated by 2-deoxy-D-glucose in both GM-CSFrh-pretreated and GM-CSFrh- untreated granulocytes, retardation of the subsequent phase of alkalinization was observed in GM-CSFrh-primed cells even after inhibition of both glycolytic and mitochondrial metabolism. Our data indicate that the increased cytosolic acidification following fMLP stimulation in granulocytes "primed" with GM-CSFrh does not result from disordered proton excretion but instead from increased release of intracellular free acid which is only partially coupled to glucose catabolism or to the generation of superoxide anion (O2-).     

A screening test for assessing iron status

Intervention strategies to combat iron deficiency anemia in developing countries may hasten the development of iron overload in patients with an inherited defect in hemoglobin synthesis. This risk could be diminished if there was a rapid and simple method available for detecting iron overload in population screening programs. We have developed such a method, which is in effect a semiquantitative ferritin measurement based on a modification of a two-site enzyme-linked immunoassay. The assay requires only 2 drops of whole blood and a total incubation time of 90 min. The procedure, which can readily distinguish iron deficiency from even a modest increase in storage iron, has a potentially wide application in settings where a prompt assessment of iron status is required.