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Biomedical subjects

E Voss

Publications and source records attributed to E Voss.

At least 19 recordsLinked to original sources
PubMed1995

Cardiac troponin, CK-MB and myoglobin for the early detection of acute myocardial infarction and monitoring of reperfusion following thrombolytic therapy.

It is important to establish as soon as possible whether patients who present with chest pain are having an acute myocardial infarction (AMI). Ideally, sensitive and specific serum myocardial markers could provide the basis for early detection as well as determine the status of reperfusion following thrombolytic therapy. The present study examined the utility of cardiac troponin I (cTnI), CK-MB, and myoglobin for the sensitive and specific detection of AMI in 98 consecutive patients presenting to the emergency department (ED) with chest pain. In addition, cardiac troponin T (cTnT), CK-MB, and myoglobin samples were measured over a 90 min time period following thrombolytic therapy in nine separate AMI patients to assess reperfusion. In the ED study, CK-MB, myoglobin, and cTnI were equally sensitive (100%) for the detection of AMI in patients who presented 7.4-14 h after onset of chest pain. However, cTnI was the most specific serum marker (specificity 91.9% compared to CK-MB 85.6%, myoglobin 61.4%). Five of the six non-related AMI patients who had an elevated cTnI had clinically documented myocardial involvement. In the reperfusion study, cTnT, CK-MB and myoglobin, relative increases were greater in reperfused compared to non-reperfused patients. Within the reperfused group, the relative increase of cTnT was greater than CK-MB and myoglobin at 90 min following thrombolytic therapy. These findings show the clinical utility of cardiac-specific troponins as markers for the early detection of AMI and monitoring of reperfusion following thrombolytic therapy.

Creatine Kinase↗
PubMed1992

Three-dimensional motility cycle in leukocytes.

A 3-dimensional dynamic image analyzing system (3D-DIAS) has been developed in which a translocating cell is optically sectioned in the z-axis within a 2 sec period; the perimeter of the cell in each section is digitized into the 3D-DIAS data file, and the digitized perimeters are wrapped in order to reconstruct the cell image in three dimensions. Using 3D-DIAS, we have obtained the first dynamic 3-dimensional description of human polymorphonuclear leukocytes (PMN) translocating on a glass surface. A general behavior cycle has emerged which includes two phases. In the first, an ellipsoidal PMN with significant z-axis extends anteriorly and descends to the substratum. When the ventral surface of the anterior end contacts the substratum, there is rapid anterior expansion, which correlates with velocity peaks. In the second phase, the elongate PMN stops translocating along the substratum, the anterior end lifts off of the substratum, sometimes to heights greater than the length of the PMN at the substratum, and finally the PMN retracts into an ellipsoidal morphology still capable of random protrusions. During this second phase, which correlates with velocity troughs, turning usually occurs. The degree of turning is restricted by the continuous integrity of the posterior uropod. The period of the behavior cycle varies from roughly 0.5 to 2 min between PMNs, but is relatively constant within each individual PMN.

Cell Movement↗
PubMed1990

Intracellular vesicle movement, cAMP and myosin II in Dictyostelium.

Dictyostelium amoebae were analyzed before and after rapid addition of 10(-6) M cAMP for cellular motility, dynamic shape changes, and intracellular particle movement. Before cAMP addition, amoebae moved in a persistent anterior fashion and were elongate with F-actin localized predominantly in the anterior pseudopod. Intracellular particles moved rapidly and anteriorly. Within seconds after 10(-6) M cAMP addition, cells stopped translocating, pseudopod formation ceased, intracellular particle movement was depressed, and F-actin was lost from the pseudopod and concomitantly relocalized in the cell cortex. After 10 seconds, expansion zones reappeared but were small and no longer anteriorly localized. Vesicle movement partially rebounded but was no longer anteriorly directed. The myosin II null mutant HS2215 exhibited both depressed cellular translocation and vesicle movement. The addition of cAMP to HS2215 cells did not result in any detectable change in the random, depressed movement of particles. The results with HS2215 suggest that myosin II is essential for (1) rapid cellular translocation, (2) cellular polarity, (3) rapid particle movement, (4) anteriorly directed particle movement, and (5) the cAMP response. Electron micrographs suggest that at least half of the particles examined in this study contain in turn smaller membrane bound vesicles or multilamellar membrane bodies. The possible role of these vesicles is discussed.

Actins↗
PubMed1990

Switching at the cellular level in the white-opaque transition of Candida albicans.

The 'white-opaque transition' in Candida albicans strain WO-1 provides a unique system for analysing high-frequency switching at the cellular level because of the difference in the budding phenotypes of the white and opaque phases. Single white and opaque cells were placed on agar and monitored for the dynamics of cell division, microcolony genesis and switching to the alternative phase. It is demonstrated that at 24 degrees C, opaque cells can switch directly to white cells but white cells first generate an elongate, pseudohyphal-shaped precursor in the transition to an opaque cell. Cells in either phase can generate a daughter cell in the alternative phase, then revert immediately to the genesis of subsequent daughter cells in the original phase. By developing a mathematical model for switching at the cellular level which subtracts mother cells and switched daughter cells from the pool of switching candidates, the probability for an opaque cell to generate a white daughter cell in any single generation was calculated to be 1.0 x 10(-1) and the probability for a white cell to generate an opaque daughter cell in any single generation was calculated to be 1.7 x 10(-5) at 24 degrees C on nutrient agar. The mean number of generations before an opaque cell generated a white daughter cell was calculated to be 3.4 and the mean number before a white cell formed an opaque cell was calculated to be 15.8 at 24 degrees C on nutrient agar. Finally, high-temperature induction of the opaque to white transition was analysed at the cellular level and demonstrated to involve frequent bipolar formation of white daughter cells on the original opaque mother cell, and in some cases intermediate phenotypes.

Candida albicans↗
PubMed1990

Computer-assisted methods for assessing strain relatedness in Candida albicans by fingerprinting with the moderately repetitive sequence Ca3.

When used to probe EcoRI-digested Candida albicans DNA, the moderately repetitive sequence Ca3 generated a Southern blot hybridization pattern which included 15 to 25 bands, depending upon the strain. The pattern was stable through 400 generations in each of three independent strains but variable between most of 46 unrelated tester strains, making it a very effective probe for discrimination between strains. Computer-assisted methods (Dendron) were developed for storage of Ca3 patterns in data files, calculation of similarity (SAB) values between strains based upon band positions and intensities, and generation of histograms and dendrograms based on SAB values for all strains or any subset of strains in large epidemiological studies. In testing the effectiveness of the system, it was found that (i) multiple isolates from different body locations of the same healthy individual could represent either the same strain or different strains, (ii) isolates from oral lesions of a husband and wife represented the same strain, (iii) strains isolated from the mouths of 10 healthy individuals on the same day and in the same geographical location were as dissimilar on average as the 46 unrelated tester strains, and (iv) strains isolated from seven immunocompromised patients hospitalized over a 2.5-month period in the same hospital were highly similar, indicating nosocomial origin. The apparent effectiveness of these fingerprinting methods and the Dendron program suggests that interlaboratory procedures for fingerprinting should be standardized and all patterns should be analyzed and stored in a common and accessible data base for broad epidemiological analysis.

Blotting, Southern↗
PubMed1990

Differential regulation of right and left ventricular beta-adrenergic receptors in newborn lambs with experimental cyanotic heart disease.

To determine whether chronic hypoxemia secondary to an intracardiac right-to-left shunt alters regulation of the myocardial beta-adrenergic receptor/adenylate cyclase system, we produced chronic hypoxemia in nine newborn lambs by creating right ventricular outflow obstruction and an atrial septal defect. Oxygen saturation was reduced to 65-74% for 2 wk. Eight lambs served as normoxemic controls. beta-receptor density (Bmax) and ligand affinity (KD) were determined with the radio-ligand [125I]iodocyanopindolol and adenylate cyclase activity determined during stimulation with isoproterenol, sodium fluoride (NaF), and forskolin. During chronic hypoxemia, Bmax decreased 45% (hypoxemic, 180.6 +/- 31.5 vs. control, 330.5 +/- 60.1 fmol/mg) in the left ventricle (exposed to hypoxemia alone) but was unchanged in the right ventricle (exposed to hypoxemia and pressure overload). KD was not different from control in either ventricle. Left ventricular isoproterenol-stimulated adenylate cyclase activity was decreased by 39% (30.0 +/- 4.3% increase vs. 44.1 +/- 9.5% increase) whereas right ventricular adenylate cyclase activity was unchanged. Stimulation of adenylate cyclase with NaF or forskolin was not different from control in either ventricle. Circulating epinephrine was increased fourfold whereas circulating and myocardial norepinephrine were unchanged. These data demonstrate a down-regulation of the left ventricular beta-adrenergic receptor/adenylate cyclase system during chronic hypoxemia secondary to an intracardiac right-to-left shunt.

Adenylyl Cyclases↗
PubMed1989

A prospective study of the active management of labor in women of high parity.

High parity has been suggested as contra-indication for the use of oxytocin stimulation in labor. The aim of our study was to prospectively evaluate a protocol of oxytocin administration in 130 consecutive low-risk patients having their sixth or subsequent delivery. Induction of labor failed only in 5 cases. No adverse effect on maternal and perinatal outcome was found. We conclude that with the introduction of electronic fetal monitoring and direct recording of uterine activity, oxytocin can be safely used for low-risk grand multiparae.

Adult↗
PubMed1989

cAMP-mediated inhibition of intracellular particle movement and actin reorganization in Dictyostelium.

Before addition of cAMP, Dictyostelum amoebae rapidly translocating in buffer are elongate, exhibit expansion zones primarily at the anterior end and filamentous actin (F-actin) localization primarily in the anterior pseudopodia. Intracellular particle movement is primarily in the anterior direction, and the average rate of particle movement is roughly five times the rate of cellular translocation. Within seconds after the addition of 10(-6)M cAMP, there is a dramatic suppression of cellular translocation, an inhibition of pseudopod formation, a freeze in cellular morphology, a dramatic depression in intracellular particle movement, loss of F-actin localization in pseudopodia concomitant with relocalization of F-actin in the general cytoplasmic cortex under the plasma membrane, and a doubling of F-actin content. After 10 s, expansion zones are again visible at the cell perimeter, but they no longer are localized in the original anterior portion of the cell. There is a slight rebound in particle movement after 10 s, but particles with persistent tracks now show no directionality towards the original anterior portion of the cell, as they did before cAMP addition. Finally, in parallel with the resumption of peripheral expansion and the small rebound in particle movement, there is a decrease in total cellular F-actin to the untreated level. The pattern of microtubule organization is unaffected by the addition of cAMP.

Actins↗
PubMed1989

Controlled prospective study of oral amoxycillin/clavulanate vs ciprofloxacin in acute exacerbations of chronic bronchitis.

This investigation compared the efficacy of oral formulations of amoxycillin/clavulanate and ciprofloxacin in acute exacerbations of chronic bronchitis. Forty patients were randomized to receive either Augmentin (1,000 mg amoxycillin +250 mg clavulanate) tds or ciprofloxacin (500 mg) bd. During and before therapy sputum samples were taken for bacteriology, sputum volume measurement and histamine determination. Lung function was also monitored. From sputum, 143 bacterial isolates and 15 yeast strains were obtained before therapy. During therapy with amoxycillin/clavulanate the incidence of Gram-positive isolates decreased significantly whereas ciprofloxacin left their frequency unchanged. On the other hand, ciprofloxacin more effectively diminished the incidence of Gram-negative isolates. Yeasts were grown from the sputum of several patients before and during therapy. Their number did not increase during amoxycillin/clavulanate therapy while it increased under ciprofloxacin. The groups showed no significant differences with regard to sputum production, histamine concentration or lung function. The majority of patients (28/40) acknowledged improvement of their symptoms. There was no significant difference between the groups. On the basis of these results both amoxycillin/clavulanate and ciprofloxacin appear of similar value for treatment of patients with exacerbations of chronic bronchitis.

Aged↗
PubMed1988

"Dynamic Morphology System": a method for quantitating changes in shape, pseudopod formation, and motion in normal and mutant amoebae of Dictyostelium discoideum.

An automated, video-driven system was used to measure approximately 30 parameters of cell motion and accompanying changes in shape. This "Dynamic Morphology System" is based upon the Expertvision Motion Analysis System and is driven by a SUN computer. With the aid of this system, amoebic movement and shape changes were compared for vegetative wild-type Dictyostelium discoideum amoebae and a motility mutant, Mo-1. The measured parameters included speed, angle change, bearing, length, width, roundness, boundary flow, and curvature; and cell behavior was visualized monitoring amoebic tracks, difference pictures, and a newly developed ring expansion plot. Wild-type cells remained elongated, moved continuously and retained polarity throughout migration. In contrast, Mo-1 did not translocate, was round rather than elongated, formed bulges rather than elongated pseudopods, and exhibited no polarity. In contrast to the anterior f-action distribution in wild-type cells, f-actin in Mo-1 was distributed evenly as a shell just under the entire plasma membrane, a distribution consistent with the lack of polar cytoplasmic expansion.

Actins↗
PubMed1987

Amebae of Dictyostelium discoideum respond to an increasing temporal gradient of the chemoattractant cAMP with a reduced frequency of turning: evidence for a temporal mechanism in ameboid chemotaxis.

In an aggregation territory of Dictyostelium discoideum, outwardly moving, nondissipating waves of the chemoattractant cAMP sweep across each ameba. At the front of each wave, an ameba experiences an increasing temporal and a positive spatial gradient of cAMP. At the back of a wave, an ameba experiences a decreasing temporal and a negative spatial gradient of cAMP. Employing a perfusion chamber, we have mimicked the temporal dynamics of these waves in the absence of a spatial gradient and demonstrated that the frequency of lateral pseudopod formation and the frequency of turning are dramatically affected by the direction and dynamics of the temporal gradient. In addition, since an ameba will move in a directed fashion up a shallow, nonpulsatile gradient of cAMP, we also mimicked the increasing temporal gradient generated by an ameba moving up a shallow spatial gradient. The frequency of lateral pseudopod formation and the frequency of turning were depressed. Together, these results demonstrate that amebae can assess the direction of a temporal gradient of chemoattractant in the absence of a spatial gradient and alter both the frequency of pseudopod extension and turning, accordingly. Although these results do not rule out the involvement of a spatial mechanism in assessing a spatial gradient, they strongly suggest that the temporal dynamics of a cAMP wave or the temporal gradient generated by an ameba moving through a spatial gradient may play a major role in chemotaxis.

Cell Movement↗
PubMed1987

Frequency and orientation of pseudopod formation of Dictyostelium discoideum amebae chemotaxing in a spatial gradient: further evidence for a temporal mechanism.

Amebae of Dictyostelium discoideum normally chemotax to aggregation centers by assessing the direction of outwardly moving, nondissipating waves of the chemoattractant cAMP. However, D. discoideum amebae can also assess the direction of a relatively stable spatial gradient. We demonstrate that amebae migrating towards the "source" of a stable, spatial gradient move faster, extend fewer pseudopodia, and turn less frequently than amebae migrating away from the "source" in the same spatial gradient. In addition, amebae extend lateral pseudopods in a polarized fashion from the anterior half of the cell, and do so as frequently towards the source as away from the source. However, those formed towards the source more often produce a turn than those formed away from the source. These results suggest that there may be two decision-making systems, one localized in the pseudopods, and one along the entire cell body; they support the suggestion that Dictyostelium amebae may employ a temporal mechanism to assess the direction of a spatial gradient of chemoattractant.

Cell Movement↗
PubMed1986

Enzyme immunoassay of serum cortisol using a new transferable needle lid technique.

A simple enzyme immunoassay of serum cortisol using for the first time a transferable needle lid as solid phase has been developed. The needles coated with second antibody and dipped into the wells of a microtitre plate bind the specific antibody of a competitive enzyme immunoassay mixture. Bound enzyme activity is estimated in the wells of another microtitre plate. This technique provides further advantages on the frequently used microtitre plate version. Washes between the immunological and the enzymatic reaction take very short time and are less laborious. Due to the facility of simultaneous starting and stopping of all reactions, a better precision and sensitivity is achieved. In the present cortisol assay, horseradish peroxidase covalently coupled to cortisol-21-hemisuccinate was used as enzyme label and tetramethylbenzidine as the chromogen for measuring enzyme activity. No extraction or deproteinization steps are involved. The turn around time for 41 samples (in duplicate) is 2.5 h. The detection limit of the assay is 5 pg of cortisol per well. Results of the present method correlated well (r = 0.92) with those of a commercial radioimmunoassay using iodinated cortisol.

Humans↗
PubMed1986

Simultaneous enzyme immunoassay of cortisol and dehydroepiandrostone-sulphate from a single serum sample using a transferable solid phase system.

An enzyme immunological methodology for the direct and simultaneous estimation of serum cortisol and dehydroepiandrosterone-sulphate (DHEA-S) useful for the biochemical differential diagnosis of Cushing's syndrome has been developed. The combined estimation of both steroids is more economical in time, work and materials than two separate assays. Two solid phases, a microtitre plate and a covering transferable needle lid system were used in the present procedure. Both solid phases are first coated with anti-rabbit IgG and then each with a specific antiserum. Horseradish peroxidase was used as marker enzyme and tetramethylbenzidine as the chromogen for measuring enzyme activity. No extraction or deproteinization steps are involved. The turn around time for 41 samples (in duplicate) is 3 h. The detection limit of the assay is 5 pg/well for cortisol and 10 pg/well for DHEA-S. Results of the present method correlated well (cortisol, r = 0.95; DHEA-S, r = 0.98) with those of commercial radioimmunoassays using iodinated labels. Thus, this technique offers a convenient non-isotopic procedure in the routine clinical laboratory.

Dehydroepiandrosterone↗
PubMed1985

Amorphic lenses: a mobility aid for patients with retinitis pigmentosa.

An amorphic lens, designed by William Feinbloom, was tested on 69 patients with retinitis pigmentosa. The results showed that one-half of the patients experienced immediate improvement in mobility and one-third of the patients fitted with the amorphic lens reported (after wearing the lenses for 2 weeks) improved mobility compared to their mobility before using the lens.

Equipment Design↗
PubMed1984

[Importance of transvenous digital subtraction angiography (DSA) in detecting vascular complications following aorto-iliac/femoral bifurcation bypass].

From 1970 to 1984 late complications including the prox. anastomosis of aortoiliacal/-femoral bifurcation-prothesis were observed angiographically in 37/647 (6.5%) of patients with art. occl. disease and 4/367 (1.1%) of patients with aneurysmatic disease. Concerning the dist. bilateral anastomotic region the complication-rate was markedly higher. This study was carried out to evaluate accuracy of transvenous DSA in a preselected outpatient group (n = 24) following aortoiliacal/-femoral bifurcation-bypass. In 15 cases DSA showed prothetic complications such as occlusion (n = 4), stenosis (n = 2), anastomotic aneurysms (n = 8) and a.v. fistula (n = 1). The results demonstrate that in outpatients transvenous DSA is a method of low risk to get excellent images of bifurcation-prothesis and prothetic complications considering recommended technical criteria.

Aged↗