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Biomedical subjects

S Wagner

Publications and source records attributed to S Wagner.

At least 379 records · Page 21Linked to original sources
PubMed1990

[Three-dimensional analysis of the regional contractility of the normal and the cardiomyopathic left ventricle using cine-magnetic resonance imaging].

The left ventricular regional contractile pattern, global function and mass of normal subjects and patients with idiopathic dilated cardiomyopathy was compared using cine magnetic resonance imaging (MRI) in a short-axis imaging plane. Left ventricular ejection fraction and mass were 64.3 +/- 2.5% and 115 +/- 10 g in normal hearts and 23.5 +/- 3.1% and 194 +/- 20 g in dilated cardiomyopathic hearts (p less than 0.001 and p less than 0.002). Left ventricular end-diastolic wall thickness was homogeneous in normal hearts except for the posterior wall at the basal level, which was significantly thinner compared to the anterolateral wall and the septum (p less than 0.02). End-diastolic wall thickness in the cardiomyopathic group was significantly more heterogeneous and was thinner at the apical compared to the basal level (p less than 0.02) as well as in the segment of the posterior compared to the anterolateral and septal wall (p less than 0.005 and p less than 0.03). In normal hearts, left ventricular end-systolic wall thickness was progressively greater from base to apex for the anterolateral (p less than 0.01) and posterior wall (p less than 0.02) and the septum (p less than 0.02). Such a uniform gradient of end-systolic wall thickness was not present in hearts with dilated cardiomyopathy. It was even reversed for the anterolateral wall with decreasing thickness from base to apex (p less than 0.03). Left ventricular mean systolic wall thickening increased progressively from base to apex (p less than 0.005) in normal hearts, whereas there was no significant gradient from base to apex in hearts with dilated cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Histo- and immunomorphometry of megakaryopoiesis in chronic myeloid leukemia with myelofibrosis and so-called primary (idiopathic) osteo-myelofibrosis/-sclerosis.

A morphometric study was performed on trephine biopsies of bone marrow in patients with chronic myeloid leukemia (CML) accompanied by myelofibrosis and in so-called primary (idiopathic) osteomyelofibrosis/-sclerosis (OMF) to evaluate distinctive features of megakaryopoiesis. The periodic acid Schiff reaction (PAS) and a monoclonal antibody against glycoprotein IIIa were employed for the identification of megakaryocytes including precursor cells and Gomori's silver impregnation to determine the density of argyrophilic fibers. All patients with CML revealed a slight to moderate degree of medullary fibrosis and were compared with early hyperplastic stages of OMF showing an identical fiber count. Statistical analysis disclosed that distinctive features existed between these two subgroups. Amongst these variables were sizes of megakaryocytes and corresponding nuclei, frequency of bare nuclei, emperipolesis and numbers of isolated nuclear fragments as well as the circular deviation of cell and nuclear perimeters. Immunomorphometry also included immature elements (pro- and megakaryoblasts) of the megakaryocyte series. Consequently higher cell counts were calculable in both groups combined with smaller sizes and a more rounded aspect of nuclei. However, following immunostaining, significant differences in several megakaryocytic parameters (frequency, size, shape of nuclei) were still demonstrable between CML and OMF cases.

Adult↗
PubMed1990

[Juvenile occlusion syndrome of the inferior vena cava with left renal deficiency].

In three juvenile patients, one female and two males aged 14 to 21 years, there were recent deep vein thromboses of the lower limbs due to previous infrahepatic occlusion of the inferior vena cava associated with a shrunken left kidney without clinical manifestation of a nephrotic syndrome. Possible reasons and impacts of this probably congenital peculiar vascular syndrome are discussed. Radiodiagnostic management in juvenile patients with recurrent venous thromboses of the lower part of the body is explained with special respect to secondary phenomena of other retroperitoneal organs like adrenals, inner pelvis and testicles.

Adolescent↗
PubMed1989

[Erythrohepatic protoporphyria with rapidly progressing liver cirrhosis].

A 49-year-old man, known to have had an increased light sensitivity since childhood, was admitted to hospital because of jaundice. Biochemical and morphological examination revealed cirrhosis of the liver with cholestasis. There was a 70-fold increase of protoporphyrin content in the erythrocytes, increased fecal protoporphyrin excretion as well as secondary coproporphyrinuria. Despite symptomatic treatment with ursodeoxycholic acid and cholestyramine hepatic failure ensued for which orthotopic liver transplantation was performed five months after the diagnosis had been made. The patient died two months later of treatment-resistant septicaemia and multiorgan failure. This case demonstrates the need for annual monitoring of liver functions and porphyrin parameters to ensure earliest possible diagnosis of hepatic involvement in erythrohepatic protoporphyria.

Cholestyramine Resin↗
PubMed1989

Transformation of Neurospora crassa by an integrative transforming plasmid is not enhanced by ribosomal DNA sequences.

Two integrative transforming plasmids of Neurospora crassa that differed only by the presence of almost all of a ribosomal DNA repeat unit on one plasmid were constructed. The plasmids were used to test the target concentration hypothesis which states that the transformation frequency is proportional to the number of genomic copies of a homologous sequence located on the transforming plasmid. Since there are approx. 200 copies of the rDNA sequences in the genome, the target concentration hypothesis would have been proved if the transformation frequency was 200-fold higher for the rDNA-containing plasmid compared with the plasmid without rDNA. The results indicated no difference in the transformation for the two plasmids, thereby providing no support for the hypothesis. The target concentration hypothesis has been proved for yeast, and thus mechanisms different from that responsible for integrative transformation in yeast must operate in N. crassa, perhaps including non-homologous recombination events.

DNA, Fungal↗
PubMed1989

[Epidemiology and therapy of Campylobacter pylori infection].

The prevalence of Campylobacter pylori in gastric mucosa was investigated prospectively (by histology, cytology, bacterial culture and urease rapid-test) in 302 patients of a routine gastroenterological endoscopy programme. According to the histopathological findings the following prevalence of C. pylori was established: 3 of 35 normals (9%); 116 of 167 with antral gastritis (69%), 28 of 40 with gastric ulcers (70%); 26 of 33 with duodenal ulcers (79%); 5 of 27 with other conditions (19%). The activity degree of the gastritis correlated closely with the presence of C. pylori. In a prospective open trial 110 patients with antral gastritis or gastroduodenal ulcer were treated according to the following schedule: (a) bismuth subsalicylate, 1800 mg/d for four weeks (35 patients); (b) amoxycillin 2250 mg/d for two weeks (6); (c) ranitidine 300 mg/d for four weeks (26); (d) bismuth plus amoxycillin (20); (e) bismuth plus ranitidine (23). Immediately after the end of treatment and four weeks later the elimination rates were: (a) bismuth 51% (18) and 23% (8), respectively; (b) amoxycillin 50% (3) and 17% (1); (c) ranitidine 0% (0); (d) bismuth plus amoxycillin 60% (12) and 25% (5); (e) bismuth plus ranitidine 43% (10) and 17% (4). These data indicate that treatment with bismuth plus amoxycillin will achieve a negative bacterial result in about half the patients. But frequently as early as four weeks later C. pylori can again be demonstrated, so that the long-term elimination rate is only 15-30%.

Adult↗
PubMed1989

Diagnostic accuracy and estimation of the severity of valvular regurgitation from the signal void on cine magnetic resonance images.

Anomalous blood flow caused by valvular regurgitation can be visualized as a narrowly defined area of signal loss in contrast to the high intensity of the blood pool on repetitive gradient refocused magnetic resonance (MRI) (cine MRI) views. In order to assess the accuracy of identification and measurements of the signal void in the evaluation of mitral (MR) and aortic regurgitation (AR), the cine MRI studies of 62 patients with regurgitation and of 20 normal volunteers were retrospectively analyzed in a blinded study of three independent reviewers. Accuracy for detection of MR was greater than 0.96 and for AR was greater than 0.91 for all three reviewers. The total volume of the signal void associated with regurgitation was measured on cine MRI images of 58 patients by two independent observers. The patients were divided into three groups of severity based upon assessment of severity of regurgitation by two-dimensional echocardiography and/or angiography. The total volume of signal loss was 9.0 ml (+/- 0.94 SEE; n = 18) for mild MR, 30.7 ml (+/- 5.3 SEE; n = 11) for moderate MR, and 83.4 ml (+/- 17.4 SEE; n = 5) for severe MR. In patients with AR, the calculated signal void was 27.3 ml (+/- 3.2 SEE; n = 24) in mild, 49.7 ml (+/- 2.9 SEE; n = 7) in moderate, and 75.8 ml (+/- 5.7; n = 6) in severe cases. The differences in the volume of the signal void were significant among the three groups of severity (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1989

Adjustment to intermittent access in rats drinking saccharin: II. Adjustment of lapping rate.

Hungary rats were permitted to drink saccharin under conditions in which (a) the drinking spout was available continuously, or (b) it was withdrawn during alternate 30-sec periods. Rats adjust to such constraint by increasing their integrated lap rate (laps/min). We show that one way in which they do this is to lap at a higher rate within bursts of lapping. This faster lapping is not an artifact of forced interruptions and resumptions. It cannot only be maintained over a drinking session, but also initiated midway through the session if restricted access is imposed then. Therefore, the period of the lapping cycle can be adjusted, within limits, in response to situational constraints on access to the fluid.

Animals↗
PubMed1989

Orosensory suppression of saccharin drinking in rat: the response, not the taste.

Hungry rats drink saccharin solutions with avidity, but the ingestion is self-limited: rate of lapping slows down progressively. Since postingestive changes do not produce this suppression, it must depend on a feedback signal generated by lapping the fluid. We show that the suppression depends on the number of laps emitted, not on the taste of the fluid; a given number of laps early in the session produces the same suppression later in the session, whether those early laps are accompanied by a moderate saccharin taste, a weak taste, or no sweet taste at all. Therefore, the feedback signal is provided by the act of lapping; taste does not contribute to it. Yet taste does influence amount ingested. Perhaps it provides a feed-forward signal, that in turn sets the amount of feedback required to end the bout.

Animals↗
PubMed1989

Noninvasive evaluation of global left ventricular function with use of cine nuclear magnetic resonance.

Previous reports have validated the accuracy of nuclear magnetic resonance (NMR) imaging for quantitating ventricular volumes and myocardial mass. In this study, a new rapid NMR imaging method, cine NMR imaging, was used to compare left ventricular volumes determined from the transverse plane and short-axis plane in healthy volunteers and patients with dilated cardiomyopathy. With use of the short-axis plane, left ventricular mass at end-systole and end-diastole were determined and left ventricular systolic wall thickening at three different levels was assessed. For validation in the current study, cine NMR imaging and two-dimensional echocardiographic measurements of left ventricular volumes were correlated. Left ventricular volumes of the normal volunteers (end-systolic volume = 34 +/- 3.8 ml, end-diastolic volume = 90.4 +/- 7.2 ml) and patients with cardiomyopathy (end-systolic volume = 173 +/- 28.3 ml, end-diastolic volume = 219.5 +/- 29.6 ml) obtained in the transverse plane were nearly identical to those obtained in the short-axis plane (normal volunteers, end-systolic volume = 30.3 +/- 3.5 ml, end-diastolic volume = 84.7 +/- 7.0 ml and patients with cardiomyopathy, end-systolic volume = 179.1 +/- 27.8 ml, end-diastolic volume = 227 +/- 30.9 ml) and correlated highly (r = 0.91) with volumes obtained by two-dimensional echocardiography. Assessment of left ventricular mass over a broad range using cine NMR imaging in a short-axis plane was identical at end-systole (normal volunteers, 117 +/- 10 g; patients with cardiomyopathy, 202 +/- 20 g) and end-diastole (normal volunteers, 115 +/- 10 g; patients with cardiomyopathy, 194 +/- 21 g).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The treatment of essential thrombocythaemia with radioactive phosphorus.

The major complications of essential thrombocythaemia include haemorrhage and thrombosis, events which are related to the level of the abnormal platelet count. We report here on the use of radioactive phosphorus (32P) in eight patients with essential thrombocythaemia. Two patients required multiple injections of 32P to control platelet count, and there was no reduction in the rate of fall of platelets with each injection. Three patients required chemotherapy for persistent thrombocythaemia despite multiple doses of 32P. No clinical or haematological characteristics could be identified for those patients whose disease was difficult to control. Radioactive phosphorus is a safe and effective method to control platelet counts in patients with essential thrombocythaemia.

Adult↗
PubMed1989

Magnetic resonance imaging of acute myocardial ischemia using a manganese chelate, Mn-DPDP.

Nine adult rats underwent occlusion of the left coronary artery (LCA) to assess the ability of a manganese chelate of N, N'-Bis (pyridoxal-5-phosphate) ethylenediamine-N, N'-diacetic acid (Mn-DPDP), to delineate acute myocardial ischemia. Hemodynamic effects of the contrast medium were tested in the isolated rat heart. Gated transaxial images of the heart at the mid-ventricular level were obtained using a 2 Tesla magnet. A TE of 20 msec and a TR of 1 R-R interval (approximately 250 msec) were used. Images were taken prior to injection of 400 mumol/kg of Mn-DPDP, 2 minutes after injection, and then at 15 minute intervals for one hour. The time between LCA occlusion and injection of contrast averaged 95 minutes. The signal intensity (SI) of normal myocardium was increased by 125 +/- 9% immediately after injection, and did not significantly vary over one hour. SI of ischemic myocardium increased by only 16 +/- 14% immediately after injection, gradually rising to 44 +/- 13% after one hour. Visual discrimination between normal and ischemic myocardium was obtained throughout the study. The percent contrast between normal and ischemic myocardium was 47.2 +/- 6% at 2 minutes after injection, gradually decreasing to a final value of 31.3 +/- 4%. No hemodynamic effects were produced in the isolated heart using concentrations in the perfusate several-fold higher than those expected to be produced by the intravenous injection of 400 mumol/kg Mn-DPDP. Mn-DPDP shows the potential for delineation of the jeopardy area resulting from coronary occlusion for at least one hour after injection of the agent.

Animals↗
PubMed1989

Occlusive and reperfused myocardial infarcts: differentiation with Mn-DPDP--enhanced MR imaging.

To assess whether the administration of manganese N,N'-bis(pyridoxal-5-phosphate)ethylenediamine-N,N'-diacetic acid (DPDP) permits differentiation between occlusive and reperfused infarcts, the authors subjected rats to either 6 hours of left coronary artery occlusion (n = 13) or 2 hours of occlusion followed by 4 hours of reperfusion (n = 10) before magnetic resonance (MR) imaging. Electrocardiographic-gated T1-weighted images were obtained before and for 1 hour after injection of 400 mumol/kg of Mn-DPDP. On T1-weighted images obtained before injection of Mn-DPDP. no significant differences in signal intensity were observed between normal and infarcted regions. Use of Mn-DPDP permitted delineation of the area of infarction. The pattern of enhancement in the injured zone was different for occlusive and reperfused myocardial infarcts. In rats with occlusive infarcts, In rats with occlusive infarcts, three well-defined zones were seen. Epicardium and endocardium were enhanced, while the midmyocardial zone was hypointense. The midmyocardial signal intensity gradually increased during the 60 minutes after injection. In rats with reperfused infarcts, the injured area was uniformly and intensely enhanced. Histologic examination confirmed the presence and location of myocardial infarct. Mn-DPDP may improve the detection and delineation of acute myocardial infarcts, demonstrate perfusion of the infarct, and permit discrimination between reperfused and occlusive infarcts.

Animals↗
PubMed1989

Verapamil preserves myocardial performance and energy metabolism in left ventricular hypertrophy following ischemia and reperfusion. Phosphorus 31 magnetic resonance spectroscopy study.

While calcium entry blockers have a beneficial influence on the postischemic recovery of the nonhypertrophied heart, their influence on the hypertrophied heart has not been determined. The aim of this study was to assess postischemic recovery of myocardial performance and energy metabolites in rat hearts with left ventricular hypertrophy pretreated either chronically or acutely with verapamil. Left ventricular hypertrophy was induced by suprarenal constriction of the abdominal aorta. Hemodynamics and phosphorus 31 magnetic resonance spectra were monitored simultaneously in the isolated hearts during control perfusion, after 30 minutes of global ischemia, and after 30 minutes of reperfusion. All hypertrophied hearts had significantly higher rate-pressure products than normal hearts. Compared with normal hearts, oxygen consumption was significantly lower in all hypertrophied hearts, especially untreated hypertrophied hearts. Also, before ischemia all normal or hypertrophied hearts (treated or untreated) began with comparable phosphorylation potentials (i.e., the supply of energy was not significantly different). Postischemic recovery was not related to energy supply-oxygen demand before onset of ischemia. Furthermore, it was not related to energy levels or intracellular pH during ischemia. For postischemic recovery, the rate-pressure product was 40 +/- 5% in the hypertrophied heart, 83 +/- 5% in the normal, 100 +/- 3% in the hypertrophied heart chronically treated with verapamil, and 82 +/- 5% in the hypertrophied heart acutely treated with verapamil. The degree of recovery was related to coronary flow both before and after ischemia. The latter is important for flushing deleterious metabolites and ions from the interstitial space as well as for delivery of oxygen and substrate to the myocardium.

Adenosine Triphosphate↗
PubMed1989

Vibrotactile threshold shift during magnitude-estimation scaling on the hand: effects on magnitude-estimation responses and scaling behavior.

The purpose of the present study was to determine whether threshold shifts occurred during magnitude-estimation scaling of suprathreshold stimuli presented to the thenar eminence of the right hand. Possible relationships of the vibrotactile threshold shifts to suprathreshold stimulus intensity, magnitude-estimation responses, and over-all scaling behavior were explored. A single group of 14 subjects whose ages ranged from 18 to 22 yr. participated. Each subject performed two magnitude-estimation tasks. In one of the tasks threshold of sensitivity was determined after every suprathreshold numerical response of the subject. If a threshold shift was recorded, threshold was allowed to return to pretest baseline level before continuation to the next suprathreshold stimulus presentation. Analysis showed that threshold shift did occur during vibrotactile magnitude-estimation scaling on the hand and that it was related to suprathreshold stimulus intensity. Results also showed that the subjects' numerical magnitude-estimation responses and over-all scaling behavior in the form of power function exponents were not statistically different for the two scaling tasks.

Adolescent↗