Search PubMed⌕ Search

Biomedical subjects

S Wagner

Publications and source records attributed to S Wagner.

At least 199 records · Page 11Linked to original sources
PubMed1997

GABA in the mammalian suprachiasmatic nucleus and its role in diurnal rhythmicity.

Mammals manifest circadian behaviour timed by an endogenous clock in the hypothalamic suprachiasmatic nucleus (SCN). Considerable progress has been made in identifying the molecular basis of the circadian clock, but the mechanisms by which it is translated into cyclic firing activity, high during the day and low at night, are still poorly understood. GABA (gamma-aminobutyric acid), a common inhibitory neurotransmitter in the central nervous system, is particularly densely distributed within the SCN, where it is located in the majority of neuronal somata and synaptic terminals. Using an in vitro brain-slice technique, we have now studied the effect of bath-applied GABA on adult SCN neurons at various times of the day. We find that GABA acts as an inhibitory neurotransmitter at night, decreasing the firing frequency; but during the day GABA acts as an excitatory neurotransmitter, increasing the firing frequency. We show that this dual effect, which is mediated by GABA(A) receptors, may be attributed to an oscillation in intracellular chloride concentration. A likely explanation is that the amplitude of the oscillation in firing rate, displayed by individual neurons, is amplified by the dual effect of GABA in the SCN's GABAergic network.

Action Potentials↗
PubMed1997

Evaluation of synovial cytokine patterns in rheumatoid arthritis and osteoarthritis by quantitative reverse transcription polymerase chain reaction.

To compare the cytokine profile with the degree and composition of cellular infiltration in rheumatoid arthritis (RA) and osteoarthritis (OA) synovium, synovial membranes from patients with RA (n = 14) and OA (n = 5) were examined, employing immunohistochemistry and competitive reverse-transcriptase polymerase chain reaction (RT-PCR), for interleukin (IL)-I beta, IL-2, IL-4, IL-5, IL-6, and IL-10, and tumour necrosis factor-alpha (TNF-alpha) gene expression. It was found that the strength of cytokine gene expression within the synovial membranes of patients with RA was not significantly correlated with the degree of synovial infiltration of T-cells, B-cells, or macrophages. No IL-2, IL-4, or IL-5 RNA was detected in the synovium of either RA or OA. Quantitative cytokine determination showed a similar pattern in RA and OA, although the two diseases differed in total synovial infiltration and the composition of infiltrating cellular elements. Thus the number of cell types known to produce certain cytokines does not appear to determine the strength of synovial cytokine expression measured by quantitative RT-PCR. Furthermore, the pattern of T-cell specific cytokines found in RA synovium does not accord with the concept of the TH0, TH1, and TH2.

Arthritis, Rheumatoid↗
PubMed1997

[Early treatment of acute myocardial infarct: implementation of therapy guidelines in routine clinical practice, MITRA pilot phase].

The prognostic value of thrombolytics, aspirin, beta-blockers and ACE-inhibitors has been well documented in large clinical trials, but the application of these drugs in clinical practice is not known. MITRA is a multicenter study of 54 hospitals in a defined region in southwest Germany. The aim is to document actual clinical practice (pilot phase) and to establish an individually optimised prognostic therapy for acute myocardial infarction, considering only the absolute contraindications for each drug. In the pilot phase, 1303 consecutive patients with acute transmural myocardial infarction were enrolled. The median age was 66 years, the prehospital time was 2.7 hours. 47% had an anterior infarction. In the subgroup of patients without absolute contraindications, only 53.4% were treated with thrombolytics, 87.6% with aspirin, 37.1% with beta-blocker, and 17.4% with ACE-inhibitor. Out of these, patients were classified as "optimally treated" if they received thrombolysis, aspirin as well as beta-blocker. Patients were also included if any of these medications was withheld in the presence of absolute contraindications. Treatment was defined suboptimal, if the patients did not receive any of these three medications despite the absence of absolute contraindications. Only 29% (n = 383) received an optimal post-infarction therapy and 71% (n = 775) a suboptimal treatment. The univariate analysis revealed 10 variables influencing optimal therapy. In this subgroup patients were younger, they more often had clear ECG-findings or left bundle branch block, an anterior infarction, acute cardiac failure, AV-block, bradycardia, recent trauma or surgery (less then 2 weeks) and a severe chronic obstructive lung disease. The prehospital time was more often available. Early mortality after 2 days was 5.0% versus 9.3% in the suboptimal treated patients (OR: 0.5, CI: 0.30-0.86) the total inhospital mortality was 10.9% in the optimal versus 17.7% in the suboptimal group (OR: 0.6, CI: 0.38-0.84). In a multivariate analysis the parameter "optimal treatment" was found to be an independent predictor of the early (OR = 0.4; CI: 0.20-0.69) and the inhospital mortality (OR = 0.4; CI: 0.25-0.64). The following in-hospital events occurred: stroke 2.8%, reinfarction 12.9%, cardiac failure 21.5%, cardiogenic shock 10.4% and in-hospital mortality 18.1% (2-days mortality 9.5%). Pharmacological therapy for acute myocardial infarction is inconsistent with the recommendations suggested in recent clinical trials and needs to be individually optimised. Optimal treatment is an independent predictor of early and inhospital mortality.

Adrenergic beta-Antagonists↗
PubMed1997

[Intraventricular obstructions in dobutamine stress echocardiography: determinants of their development and clinical sequelae].

UNLABELLED: Dobutamine stress echocardiography (DSE) leads to strong hypercontraction, tachycardia, and peripheral vasodilatation. In previous studies systolic obstruction of the left ventricular outflow tract (LVOT) was observed as a result of these factors. To evaluate left ventricular function and morphology in patients (pts) with induced systolic LVOT obstruction, we used continuous wave (CW) doppler registrations in combination with quantitative 2-D-echocardiography in 100 pts during routinely performed DSE (5-40 micrograms/kg/min). In addition left ventricular wall thickness was measured. Symptoms were registered using a standardised questionnaire and cardiac arrhythmias were counted over a two minute interval at rest and during the maximal heart rate of each patient. During DSE dynamic flow acceleration with late systolic peak velocity above 2 m/second (s) was considered to represent LVOT obstruction in pts with normal flow profiles in the LVOT before infusion of dobutamine. For invasive studies pts were investigated with femoral catheterisation by the method of Judkins. A greater than 50% stenosis was judged to be significant. RESULTS: Examinations in 73 pts provided data of sufficient quality for echocardiographic and Doppler sonographic evaluations. 39 pts, 26 men, 13 women, mean age 64 +/- 8 years, developed late systolic flow velocities above 2 m/s and therefore formed the obstructive group (grp A). Grp B consisted of 34 pts, 26 men and 8 women, mean age 66 +/- 10 years, who showed normal time velocity integrals during DSE. In 41 pts invasive data provided information concerning the existence and severity of coronary artery disease. There were no significant differences in the increase of heart rate, the product of maximal systolic blood pressure and maximal heart rate or the percentage of pts, who reached their age corrected submaximal heart rate during DSE. Obstructive pts (group A) showed late systolic dynamic acceleration of systolic flow with a mean maximal speed of 315.4 +/- 139.8 cm/s, which peaked 0.12 +/- 0.04 s after the R-wave. From the velocities we calculated a mean pressure gradient of 47.5 +/- 39.7 mm Hg using the modified Bernoulli equation. Group B patients showed lower and earlier maximal speeds with a mean value of 158.2 +/- 37.6 cm/s, 0.09 +/- 0.04 s after the R-wave, corresponding to a pressure gradient of 10.6 +/- 4.9 mm Hg (p < 0.001). Ejection fractions were higher (p < 0.001) before the test in grp A: 68.2 +/- 8% compared to 55.7 +/- 10.4% in B. This difference increased during peak stress: 74.1 +/- 7.7% compared to 59.5 +/- 12.8%. End diastolic (EDVI) and end systolic volume indexes (ESVI) were lower in grp A (p < 0.001). During DSE, the decrease in ESVI was somewhat stronger for pts in grp A. Left ventricular hypertrophy was more often seen with obstruction. Septal thickness was increased in A: 1.45 +/- 0.34 cm compared to 1.13 +/- 0.27 cm in B (p < 0.001). Left ventricular posterior wall measured 1.03 +/- 0.28 cm in A and 0.83 +/- 0.23 cm in B (p < 0.01). 27 pts in grp B and only 9 in grp A had a history of previous myocardial infarction. Showing no difference at rest, wall motion score indexes raised under DSE in both groups and developed significantly higher scores in grp B at peak stress: 1.30 (1.0-1.90) compared to 1.18 (1.0-1.75) in A. We observed typical chest pain more often in grp B. Unspecific symptoms and arrhythmogenic complications were not statistically different, with the exception of ventricular bigeminy which was more often observed in grp B. A decline in the diastolic blood pressure was observed in pts with very severe obstruction (> 3.5 m/s, p < 0.05). Sensitivity of DSE was 84%, specificity 79%. No significant differences between pts with and without obstruction were observed. SUMMARY: Intraventricular obstructions during DSE are often observed in pts with normal systolic function at rest and during peak stress, especially in the case of left ventricular hypertrophy. (ABSTRACT TRU

Blood Flow Velocity↗
PubMed1997

[Reversibility of changes in left and right ventricular geometry and hemodynamics in pulmonary hypertension. Echocardiographic characteristics before and after pulmonary thromboendarterectomy].

Pulmonary thromboendarterectomy (PTE) leads to an acute decrease of right ventricular (RV) afterload in patients with chronic thromboembolic pulmonary hypertension. We investigated the changes in right and left ventricular (LV) geometry and hemodynamics by means of transthoracic echocardiography. The prospective study was performed in 14 patients (8 female, 6 male; age 55 +/- 20 years) before and 18 +/- 12 days after PTE. Total pulmonary vascular resistance and systolic pulmonary artery pressure were significantly decreased (PVR: preoperative 986 +/- 318, postoperative 323 +/- 280 dyn x s/cm5, p < 0.05; PAP preoperative 71 +/- 40, postoperative 41 +/- 40 mm Hg + right atrial pressure, p < 0.05). End diastolic and end systolic RV area decreased from 33 +/- 12 to 23 +/- 8 cm2, respectively, from 26 +/- 10 to 16 +/- 6 cm2, p < 0.05. There was an increase in systolic RV fractional area change from 20 +/- 12 to 30 +/- 16%, p < 0.05. RV systolic pressure rise remained unchanged (516 +/- 166 vs. 556 +/- 128 mm Hg/sec). LV ejection fraction remained within normal ranges (64 +/- 16 vs. 62 +/- 12%). Echocardiographically determined cardiac index increased from 2.8 +/- 0.74 to 4.1 +/- 1.74 l/min/m2. A decrease in LV excentricity indices (end diastolic: 1.9 +/- 1 vs. 1.1 +/- 0.3, end systolic: 1.7 +/- 0.6 vs. 1.1 +/- 0.4, p < 0.05) proved a normalization of preoperatively altered septum motion. LV diastolic filling returned to normal limits: (E/A ratio: 0.62 +/- 0.34 vs. 1.3 +/- 0.8; p < 0.05); Peak E velocity: 0.51 +/- 0.34 vs. 0.88 +/- 0.28 m/sec, p < 0.05; Peak A velocity: 0.81 +/- 0.36 vs. 0.72 +/- 0.42 m/sec, ns; E deceleration velocity: 299 +/- 328 vs. 582 +/- 294 cm/sec2, p < 0.05; Isovolumic relaxation time: 134 +/- 40 vs. 83 +/- 38 m/sec, p < 0.05). We could show a marked decrease in RV afterload shortly after PTE with a profound recovery of right ventricular systolic function--even in case of severe pulmonary hypertension. A decrease in paradoxic motion of the interventricular septum and normalization of LV diastolic filling pattern resulted in a significant increase of cardiac index.

Aged↗
PubMed1997

Probing the major skeletal muscle chloride channel with Zn2+ and other sulfhydryl-reactive compounds.

The sensitivity of the human skeletal muscle Cl- channel, hClC-1, towards various sulfhydryl-reactive agents was tested with the channel expressed in Xenopus oocytes and in human embryonic kidney cells. External but not internal Zn2+, at 1 mM, substantially reduced the current without affecting activation parameters. External Cd2+ and Hg2+ as well as organic mercurial compounds reduced the Cl- currents to a similar degree. With the mutant channel hClC-1 D136G, presumed to have a defective voltage sensor, external Zn2+ also reduced the current without effect on the altered gating. These findings suggest that hClC-1 contains cysteine residues near the extracellular face that may directly influence ion conduction. Since Zn2+ can also bind to histidine side chains, we tested the effect of compounds with either more cysteine- or more histidine-specificity. The results confirm the involvement of cysteine(s) in the observed effects but do not exclude the involvement of histidine(s).

Chloride Channels↗
PubMed1997

Regulation of gastric epithelial cell growth by Helicobacter pylori: offdence for a major role of apoptosis.

BACKGROUND & AIMS: Helicobacter pylori may affect the normal balance between gastric epithelial cell proliferation and epithelial cell death, thus interfering with the maintenance of gastric mucosal integrity. The aim of this study was to investigate the effect of H. pylori on cell growth, DNA synthesis, induction of apoptosis, and viability of human gastric epithelial cells in vitro. METHODS: H. pylori was incubated with a differentiated human gastric cancer cell line for up to 72 hours, and the effects on cell numbers (cell counts and WST-1 assay), DNA synthesis (5-bromo-2'-deoxyuridine assay and [3H]thymidine incorporation), and DNA fragmentation (DNA fluorochrome staining, transmission electron microscopy, and histone enzyme-linked immunosorbent assay) were assessed. RESULTS: Incubation of gastric epithelial cells with H. pylori led to a time- and concentration-dependent reduction of epithelial cell growth and a concomitant induction of DNA fragmentation. At high bacteria-cell ratios (> 100), inhibition of cell growth was associated with a reduction in DNA synthesis. Treatment of gastric cells with tumor necrosis factor alpha, a receptor-activating CD95/APO-1/Fas antibody, and interferon gamma markedly potentiated H. pylori-induced DNA fragmentation. CONCLUSIONS: H. pylori affects gastric epithelial cell growth by direct induction of apoptosis and inhibition of DNA synthesis and indirectly by sensitization of epithelial cells for apoptosis induced by proinflammatory stimuli.

Annexin A5↗
PubMed1997

Reactogenicity and immunogenicity of a booster dose of a combined diphtheria, tetanus, and tricomponent acellular pertussis vaccine at fourteen to twenty-eight months of age.

OBJECTIVES: The primary objective was to assess the nature and incidence of adverse events after a fourth dose of a tricomponent acellular pertussis-diphtheriatetanus vaccine given in the second year of life after primary vaccination with the same vaccine at 3, 4, and 5 months of age. A secondary objective was to analyze the immunogeniecity of the booster vaccination. DESIGN: Of the 5361 children enrolled (aged 14 to 28 months), adverse reactions were specifically solicited from the first 1863 enrollees for the first 4 days after vaccination and then were unsolicited for the remainder of the 4 weeks of follow-up (group 1). In the next 3498 subjects, safety and reactogenicify were entirely unsolicited for this 4-week period (group 2). Immunogenicity was analyzed by means of prebooster and postbooster serum antibody titers for all vaccine components in a random subgroup of 197 children from group 1. RESULTS: Soliciting symptoms elicited reports of at least one symptom in 1314 of 1809 children in group 1 (72.6%), including 993 (54.9%) with local and 885 (48.9%) with general symptoms during the first 4 days after vaccination. When symptoms were gathered in an unsolicited fashion, only 580 of 3498 children in group 2 (16.6%) had a reported symptom during this time, consisting of 344 (9.8%) local and 319 (9.1%) general symptoms, respectively. An unsolicited symptom, areactive edematous swelling of the whole thigh, occurred in 62 children (1.1%), with 45 and 17 reports in groups 1 and 2, respectively. The vast majority of all reported symptoms were mild to moderate, and all children recovered without sequelae. Fourteen serious adverse events were reported, but none was considered to be related to the vaccination. Immunogenicity analysis showed a vaccine response to pertussis toxin in 99.5% of subjects, to filamentous hemagglutinin in 98.5%, and to pertactin (69 kd outer membrane protein) in 99%. All subjects had postvaccination antibody titers of 0.1 IU/ml or greater against diphtheria and tetanus toxoids.

Antibody Formation↗
PubMed1997

Dobutamine stress Doppler echocardiography: reproducibility and physiologic left ventricular filling patterns.

Qualitatively, dobutamine stress echocardiography has become an established procedure. Quantitative results are in great demand but this is still difficult due to limited endo- and epicardial border definition. Transmitral Doppler variables are strictly quantitative and less subjective. Furthermore, ischemic alterations precede systolic ones (ischemic cascade). There are preliminary reports of the utility of dobutamine stress Doppler echocardiography, but proof of reproducibility and left ventricular filling patterns are still lacking. Fourteen healthy volunteers (10 men, 4 women, median age 25.9 years, range 21-32 years) were investigated according to the usual dobutamine stress echocardiographic protocol (5, 10, 15, 20, 30, 40 and 40 micrograms/kg/min + 0.5 mg atropine). At each titration step a standardized transmitral PW-Doppler recording with the sample volume positioned at the opened mitral leaflet tips was analyzed three times by two independent, experienced investigators. Of the early, late, and mean velocities (VmaxE, VmaxA, Vmean), time integrals (VTI-E, VTI-A, VTI), their ratios (E/A, E/A VTI), and various time intervals (Tacc, Tdec, E- and A-duration, FillT), VmaxE (0.82 to 1.09 m/s; P < 0.0001), VTI-E (16.17 to 17.19 cm; P < 0.0001) and Vmean (0.29 to 0.82 m/s; P < 0.0001) were found to have the greatest discriminatory power, commencing already at a dose of 10-15 micrograms/kg/min dobutamine. VmaxE and VTI-E demonstrated the smallest intra- and interobserver variation without any increase in variability during incremental dose titration. Assessment of the early diastolic filling pattern by Doppler echocardiography is a valuable quantitative and reproducible adjunct to conventional dobutamine stress echocardiography. Further controlled studies in coronary artery disease patients have to confirm, whether lower dobutamine doses could be used in the test and sensitivity increased due to better data acquisition in cases of limited echogenicity, less subjectivity, and earlier onset of ischemic alterations.

Cardiotonic Agents↗
PubMed1997

Quantitative assessment of aortic stenosis by three-dimensional echocardiography.

The purpose of this study was to assess the feasibility of three-dimensional echocardiography in aortic stenosis. Planimetric determination of valve area and dynamic volume-rendered display were performed. Three-dimensional echocardiography permits display of any desired plane of the cardiac structure. Thus in the case of aortic stenosis, the plane used for planimetric evaluation can be positioned exactly through the valve orifice. Dynamic volume-rendered display may provide a spatial demonstration of the stenotic valve. In 48 patients aortic valve area was measured by planimetry. The three-dimensional data set was acquired by a workstation in the course of a multiplane transesophageal examination. Results were compared with those obtained by multiplane transesophageal two-dimensional planimetric technique and invasive measurement. A dynamic three-dimensional reconstruction was displayed. Planimetric determination of valve area was possible in 42 (88%) of 48 cases. Statistical analysis of the data acquired showed a good agreement between three-dimensional echocardiography and transesophageal echocardiography (mean difference +0.018 cm2; SD = 0.086) and between three-dimensional echocardiography and the invasive technique (mean difference +0.012 cm2; SD = 0.12). Dynamic volume-rendered display was possible in 42 of 48 cases. Three-dimensional echocardiography permits accurate and reliable determination of aortic valve area. Preoperative spatial recognition of the stenotic valve is possible by dynamic volume-rendered display.

Adult↗
PubMed1997

Effects of PGE2 on amount and composition of high molecular weight glycoproteins released by human gastric mucous cells in primary culture.

The aim of this study was to determine effects of prostaglandin E2 (PGE2) on amount and composition of high molecular weight glycoproteins (HMG), released by human gastric mucous cells in primary culture. PGE2 stimulated the release of HMG, as evidenced by measurement of total carbohydrate and protein content, in a concentration-dependent manner. At the maximally tested concentration of 10(-5) mol/l, the increase amounted to 53% and 85%, over controls, for carbohydrate and protein, respectively. The stimulated release was accompanied by alterations of HMG glycosylation. As detected by lectin-ELISA, there was a relative decrease in N-acetyl glucosamine and an increase in mannose and galactose content. The sialic acid content increased in parallel to the total carbohydrate content. These results suggest that PGE2 plays a regulatory role in the synthesis and secretion of HMG by human gastric mucous cells.

16,16-Dimethylprostaglandin E2↗
PubMed1997

Dynamic stress echocardiography for evaluating anti-ischemic drug profiles in post-MI patients.

Exercise ECG is an established method of evaluating the anti-ischemic properties of drugs. However, there are considerable methodologic limitations to this procedure and its use is restricted to patients with exercise-provoked ECG alterations which can be interpreted as ischemia. The principal, earlier onset of wall motion abnormalities according to the ischemic cascade can be detected by stress echocardiography and might be utilized as a pharmacological stress testing modality. Sixteen consecutive patients (15 men, one woman; 53 +/- 9 years old) with angiographically proven coronary artery disease (8 with one-, 5 with two-, and 3 with three-vessel disease) and exercise-induced wall motion abnormalities were examined by dynamic stress echocardiography (50 watt followed by 20-watt increases/min). Anti-ischemic drugs were withdrawn prior to and on day 1; on the following day 2, 0.2 microgram/kg/min nisoldipine was infused intravenously during the test after a 3 micrograms/kg bolus was given. At maximum comparable workload 15/16 patients showed an improved wall motion score on treatment (day 1: 22.9 +/- 4.9 vs day 2: 20.0 +/- 3.9; normal score: 12; one-sided binomial test: p = 0.0003). Eight of 16 patients demonstrated ST-segment deviations on day 1 and day 2. The double product did not differ at any workload stage until the maximum of 130 watt (day 1: 14,101 +/- 3140 vs day 2: 13,365 +/- 2865; n.s.). Dynamic stress echocardiography seems to be a valuable tool in pharmacologic stress testing and in terms of accuracy is supposed to be superior to conventional exercise ECG. Nisoldipine reduces exercise-induced wall motion abnormalities in patients with and without exercise-induced ECG alterations. The data result from a controlled pilot study, and further studies are required to confirm these promising methodological and therapeutic findings.

Adult↗
PubMed1997

Methicillin resistant Staphylococcus aureus strains in the greater Düsseldorf area.

Over a period of three years the incidence of methicillin resistant Staphylococcus aureus (MRSA) isolates in 11 hospitals in the greater Düsseldorf area was observed. From a total of 7,814 S. aureus isolates, 489 (6.3%) were methicillin resistant. From 198 different patients, MRSA first isolates and 291 second isolates could be cultured. Methicillin resistance among all S. aureus isolates from 11 hospitals in the greater Düsseldorf area, ranged from 0.5 to 7.8% dependant on the size of the hospital. The highest incidence (7.8%) was found in a 1,500 bed hospital and the lowest incidence in a smaller 200 bed hospital (0.5%). With respect to the distribution among clinical departments the highest incidence of MRSA isolates was found on intensive care units and surgical wards, 25.5% and 13.0% respectively. The commonest specimen from which the MRSA isolates were cultured were respiratory secretions (17.6%) followed by central venous catheter tips (12.8%). In terms of the drug resistance pattern: all isolates were resistant to the aminoglycosides and gyrase inhibitors, whereas between 80% and 90% were sensitive to fusidic acid, chloramphenicol and pyrimethamine-sulfamethoxazole. All the strains were sensitive to the glycopeptide antibiotics, vancomycin and teicoplanin. Strain typing of 181 available first isolates (from a total of 198 first isolates) by PFGE and phage lysotyping produced identical results in more than 90% of all cases. Twenty-eight different MRSA strain types were identified by PFGE and in total 23 lysotypes could be determined. During the period of investigation an increased incidence of MRSA on an intensive care unit was observed, in which a total of 204 MRSA (42% of the total number) were isolated. The strain typing using both methods showed that on that ICU eight different MRSA types were involved in this outbreak. A hygiene plan was implemented on the unit with considerable success in reducing the incidence and spread of MRSA.

Cross Infection↗
PubMed1997

Enterotoxin and toxic shock syndrome toxin-1 production of methicillin resistant and methicillin sensitive Staphylococcus aureus strains.

In this study the production of enterotoxin A-D and toxic shock syndrome toxin-1 (TSST-1) of 181 methicillin resistant (MRSA) and 100 methicillin sensitive (MSSA) Staphylococcus aureus first isolates from different patients was investigated. All the MRSA- and MSSA isolates in the study were collected in a period between 1993 and 1995 from specimens sent from 11 different acute care hospitals in the greater Düsseldorf area. As far as possible the isolates were matched according to ward and hospital. The isolates were collected in the same time period and matched for specimen from which isolated. Furthermore, only first isolates were analysed in both groups. No significant difference in the production of toxin of any type between MRSA and MSSA could be detected (51 and 40% respectively). When the individual toxins were analysed, again no significant difference between MRSA and MSSA was demonstrable (enterotoxin production by MRSA 40% and MSSA 36%, and TSST-1 16% and 8% respectively). Despite this, a slight tendency for MRSA to produce enterotoxin A and B and for MSSA to produce enterotoxin C was observed. In addition, generation of TSST-1 by both groups was independent of enterotoxin A-D production. Interestingly, no increase in the proportion of TSST-1- or enterotoxin-producing MRSA and MSSA isolates was observed in strains isolated from blood cultures from patients with a clinical diagnosis of sepsis. Genotypical pulsed-field-gel-electrophoresis (PFGE) and phenotypical (bacteriophage typing, lysotyping) characterization of the 181 MRSA isolates resulted in 28 different PFGE patterns (of which 19 were toxin producers) and 22 lysotyping groups (18 of which produced toxin). In summary, the investigated clinical S. aureus isolates showed no difference in their ability to produce toxin and this was independent of their sensitivity to methicillin.

Bacterial Toxins↗
PubMed1997

[Approaches to objective assessment of differences in tissue textures by ultrasound equipment as a contribution to quality assurance].

PURPOSE: For clinical investigators the increasing number of ultrasonic machines with different technological equipment makes it difficult to reliably assess their ability to differentiate between the textures of various tissues. We investigated a procedure for a standardised method to measure the tissue texture when using different ultrasonic machines. METHODS: The texture parameters concern brightness, standard deviation, coefficient of variation and spatial coefficient of variation. These were calculated for three tissue phantoms with changing levels of gain and distance. These parameters, well established in literature for speckle detection, texture differentiation and contrast monitoring were useful for rapid comparison of the texture differentiation achieved by several ultrasonic machines. RESULTS: A linear relationship between standard deviation and mean image brightness seems to be an important factor for the detection of small changes in ultrasonic textures. We noticed great differences between the various ultrasonic machines tested by us. The best parameter in our set was the spatial coefficient of variation. CONCLUSION: The method allows rapid orientation regarding the ability of a machine to distinguish between several textures depending on the brightness, and offers an opportunity of determining the best working point for a given machine.

Equipment Design↗
PubMed1997

[Electron-beam tomographic imaging of the coronary arteries: an experimental comparison between monomeric and dimeric x-ray contrast media].

PURPOSE: Comparison of a monomeric and a dimeric radiographic contrast medium in the visualisation of the coronary arteries via electron beam tomography (EBT). MATERIAL AND METHODS: In a total of 6 Göttingen minipigs the heart was examined by EBT (40 sections, ECG-triggering, 1.5 mm section thickness, 100 ms acquisition time) after injection of both iopamidol (monomer, 370 mg l/ml) and iotrolan (dimer, 320 mg l/ml) at a dose of 740 mg l/kg. Injection rate and scan delay were adjusted to heart rate and circulation time. RESULTS: The intravascular increase in density after intravenous injection of iotrolan was significantly higher and longer than after injection of iopamidol (> 300 HE: 28 +/- 4 versus 17 +/- 5 cardiac cycles; p < 0.05). Iotrolan attained a higher score in the visualisation of the coronary arteries in three-dimensional surface reconstructions (p < 0.05). CONCLUSION: The dimeric contrast medium iotrolan proved superior to the monomeric agent iopamidol for visualisation of the coronary arteries via EBT.

Animals↗
PubMed1997

[Diagnosis and follow-up of muscle injuries by means of plain and contrast-enhanced MRT: experimental and clinical studies].

PURPOSE: To clarify the value of plain and contrast-enhanced MRI for the diagnosis and follow-up of muscle injuries, by means of experimental and clinical studies. METHOD: 24 Wistar rats were studied following standardized division of the calf muscles by means of MRI carried out on the first day, and also after one, two, three and four weeks. In addition, 16 patients with muscle injuries were examined (32 examinations), first between the first and fifth day of trauma, and subsequently over a period of two to seven weeks (average: four weeks). RESULTS: In the animal experiments, there was signal reduction of T1 and an increase of the T2-weighted signal during the acute inflammatory phase. During the subacute reparative phase, there was an increase of both the T1-weighted and T2-weighted signals. These became reduced during the chronic healing phase. Early differentiation between intramuscular haematomas and bleeding, surrounding oedema and recognition of the divided muscle fibres was possible only after the intravenous injection of an MR contrast medium (Gd-DTPA). Suture of the divided muscles resulted in more rapid healing without major defects. CONCLUSION: It is possible to follow up the healing process after muscle injuries by means of plain MR. Contrast-enhanced MR allows early evaluation of muscle abnormalities, and is particularly valuable for recognising the margins of the injured muscles.

Animals↗