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Biomedical subjects

I Wagner

Publications and source records attributed to I Wagner.

At least 55 records · Page 3Linked to original sources
PubMed1991

Treatment of coronary heart disease with diet and exercise--problems of compliance.

The effects of low fat diet and intensive physical exercise were examined in a randomized prospective study in patients with angiographically documented coronary heart disease. In addition to supervised regular physical exercise, patients of the intervention group (n = 18) were subjected to intensive dietary counselling with the aim of a low fat, low cholesterol diet to be maintained for at least 12 months. The control group (n = 27) received relevant advise only and usual care by private physicians. In the intervention group there was significant lowering of plasma triglycerides (202 +/- 82/141 +/- 74 mg/dl) and body weight (78.2 +/- 9.5/73.7 +/- 10.4 kg) while total and LDL cholesterol did not change significantly. There was a tendency for a rise of HDL-cholesterol (35.6 +/- 9.0/40.4 +/- 14.8 mg/dl, p = 0.07). According to 24-hour diet protocols there was a significant lowering of energy intake (2.298 +/- 697/1.602 +/- 758 kcal/day), of fat intake (111.7 +/- 44.4/52.0 +/- 23.9 g/day) and of intake of dietary cholesterol (402.8 +/- 186/161.3 +/- 100.3 mg/day) as well as of saturated fatty acids (42.5 +/- 20.4/14.3 +/- 8.1 g/day). Fatty acid composition of adipose tissue was not correlated with the patients' 24-hour dietary protocols. In the control group there were no changes of plasma lipids, body weight or diet composition according to 24-hour protocols after 1 year compared to data at the beginning of the study. There was, however, a marked correlation of adipose tissue composition and dietary information given by the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1991

Cardiac troponin T in diagnosis of acute myocardial infarction.

Troponin T is a structurally bound protein found in striated muscle cells. We tested concentrations of its cardiac-specific isotype in peripheral venous blood samples serially drawn from 72 patients with confirmed myocardial infarction. Fifty-nine patients received thrombolytic treatment with intravenous streptokinase, urokinase, or recombinant tissue-type plasminogen activator; because of contraindications, the remaining 13 patients did not. Concentrations of troponin T in plasma, measured by an enzyme-linked immunosorbent assay, started increasing within a few hours after the onset of symptoms (median, 4 h; range, 1-10 h). The sensitivity of troponin T for detecting myocardial infarction was 100% from 10 to 120 h after the onset of symptoms; sensitivity on the seventh day after admission was 84%. Concentrations were increased for up to three weeks in some patients with late or high peak values. Successful reperfusion in Q-wave infarction obviously influences the release of troponin T into plasma, with all such cases showing peak values less than or equal to 26 h (median, 14 h) after the onset of symptoms. Troponin T concentrations in these patients returned to within the reference interval more rapidly than in nonreperfused subjects. In the 13 patients without fibrinolytic therapy, troponin T tended to peak approximately 48 h (median) after the onset of chest pain. Troponin T concentrations in patients for whom thrombolysis was unsuccessful resembled those in patients without fibrinolytic therapy. The specificity of the assay was 96% as tested in samples of 96 emergency-room patients. The reference interval (less than 0.5 micrograms/L) was established from samples of 100 healthy blood donors. Troponin T measurements are a specific and sensitive method for the early and late diagnosis of acute myocardial infarction and could, therefore, provide a new criterion in laboratory diagnosis of its occurrence.

Adult↗
PubMed1989

Noise susceptibility and immunity of phase locking in amphibian auditory-nerve fibers.

Recordings from auditory-nerve fibers in the anesthetized frog revealed that addition of broadband noise results in a reduction in the ability of a fiber to phase lock to a continuous pure tone. In particular, our results suggest that: (i) there is a threshold below which masking noise has little or no effect on vector strength (VS); then with increasing masking noise level, VS appears to decrease monotonically for all test frequencies (TFs); (ii) there exist subpopulations of auditory-nerve fibers in the frog for which the deterioration of phase locking to tones in wideband noise depends critically on the relationship of the TF to the fiber's CF. Specifically, in one subpopulation (43% of the fibers studied), the rate of VS decrease with increasing levels of masking noise is greater for CF tones than it is for TFs greater than CF. The net result is a "crossing" of the VS versus masking noise functions (e.g., Fig. 6); (iii) there exists a small subpopulation of amphibian papillar (a.p.) fibers for which the rate of VS decrease with increasing levels of masking noise is less for TFs less than CF than it is for CF tones (e.g., Fig. 5); (iv) there is a pronounced noise-induced phase lead for TFs greater than CF, whereas, for stimulus tones at or below CF, the preferred firing phase is nearly noise-level independent; (v) the remainder of the sample consists of fibers in which the VS-falloff rates appear to be test-frequency independent; (vi) addition of wideband masking noise to a CF tone, and increasing the CF-tone level in the absence of noise, produced (qualitatively) similar effects on the preferred firing phase of auditory-nerve fibers (e.g., Figs. 1 and 7). Thus amphibian auditory-nerve fibers appear to be energy detectors, i.e., exhibit phase shifts corresponding to the total energy within the filter passband defined by the frequency-threshold curve.

Animals↗
PubMed1989

Range estimation by echolocation in the bat Eptesicus fuscus: trading of phase versus time cues.

Bats of the species Eptesicus fuscus have been trained to discriminate a stationary simulated target from a target with a virtual distance that jitters from sound to sound. Similar to Simmons [Science 207, 1336-1338 (1979)], a jitter-detection threshold below 1 microsecond was found. However, Simmons' decreased performance at a time delay jitter of 30 microseconds could not be replicated, a critical feature used to postulate the idea that bats employ a coherent cross-correlation receiver for ranging. Such a receiver uses all phase information in the signal for delay estimation and therefore will be biased by phase manipulations. To test for such a bias, a phase jitter of +/- 45 degrees and a time jitter in the echo were overlaid. It was not found that there was a combination of both where their effects canceled. Full phase information is thus not used in delay estimation. However, bats were able to detect a pure phase jitter, e.g., polarity inversion of the signal. Bats could also detect phase jitter in the presence of randomized time jitter and vice versa. Phase jitter and time jitter, therefore, are separable features for a bat. The underlying physiological mechanism is not clear.

Amplifiers, Electronic↗
PubMed1984

Aldosterone concentrations in dehydrated infants.

The mean serum aldosterone concentration of 37 infants with acute gastroenteritis and dehydration was markedly elevated on admission (mean +/- SE 94.3 +/- 12.1 ng/ml) and approximated to normal values (18.2 +/- 3.7 ng/ml) following recovery from the acute disease (t=3.56 p less than 0.005). Serum aldosterone levels were significantly positively correlated with the percent weight loss (r=0.41, p less than 0.05) and with the blood urea nitrogen levels (r=0.55, p less than 0.001). There was no correlation between either serum sodium levels or blood osmolarity and aldosterone concentrations. Serum potassium levels were positively correlated with aldosterone levels (r=0.53, p less than 0.001). These findings indicate that small infants when dehydrated respond appropriately with elevated aldosterone levels. The amount of body fluid depletion and hyperkalemia are the major factors determining the amount of aldosterone response.

Aldosterone↗
PubMed1982

Chemotherapeutic studies on N-nitrosoacetoxymethyl-methylamine-and 1,2-dimethylhydrazine-induced colonic tumors in rats: monotherapy with 5-fluorouracil, ftorafur, CGP 6809, and CGP 15'720A.

Colonic tumors were induced in male Sprague-Dawley rats by ten applications of 2 mg/kg/week N-nitrosoacetoxymethyl-methylamine (AMMN) or by three applications of 100 mg/kg/month 1,2-dimethylhydrazine (1,2-DMH). Application of AMMN and 1,2-DMH induced selective colonic tumors in 97% and 29-42% of the initial animals, respectively. Colonic-tumor-bearing animals were subjected to monotherapy with 5-fluorouracil, ftorafur, CGP 6809, and CGP 15'720A. No cures were achieved. The different therapies did not exert any clear influence on the survival time of animals, except for animals pretreated with AMMN and then subjected to ftorafur therapy.

1,2-Dimethylhydrazine↗
PubMed1981

Determination of 5-methylcytosine from plant DNA by high-performance liquid chromatography.

The relative amounts of the five nucleosides (deoxycytidine, 5-methyldeoxycytidine, deoxyadenosine, deoxyguanosine and thymidine) in the DNA of nine plant species, one plant satellite DNA, and one animal species were determined by high performance liquid chromatography. The method allows the clean separation of the nucleosides from 10 microgram samples with 15 min. The following values for the proportion of methylated cytosines among all cytosines were obtained: Lobularia maritima 18.5%, Nicotiana tabacum 32.6%, Pisum sativum 23.2%, Rhinanthus minor 29.2%, Sinapsis alba 12.2%, Vicia faba 30.5%, Viscum album 23.2%, Cymbidium pumilum 18.8%, Cymbidium pumilum AT-rich satellite DNA 15.8%, Triticum aestivum 22.4%. DNA of an animal, the gerbil, Meriones unguiculatus, had a methylation percentage of 3.1%. An estimate of the GC content based on the buoyant density of DNA tends to be lower than the actual value, an estimate based on the melting temperature tends to be higher. This supports the finding by other authors that DNA methylation decreases the buoyant density and may increase the melting temperature at high m5C concentration.

5-Methylcytosine↗
PubMed1981

Cerebral function monitoring in deeply comatose patients.

The cerebral function monitor (CFM) was used in 26 subjects, deeply comatose for a variety of reasons, in order to determine its value as a prognosticator for survival in this group of patients. Results suggest that it may be useful in predicting outcome in patients who do not regain neurologic competence within 2 h after cardiac arrest and resuscitation. In this group, initial CFM values of 10 muv or above correlated well with survival, and values of 3 muv or below correlated with death. The instrument was not a useful tool in predicting outcome in patients with dynamic primary neurological disorders, although a reduction in the CFM tracing did precede deterioration in clinical neurological function in some. The value of the CFM could not be determined by patients with drug overdosage because of the small size of this group.

Brain↗
PubMed1981

Endoscopic diagnosis of chemically induced autochthonous colonic tumors in rats.

The suitability of using coloscopy as a diagnostic method is investigated with respect to colonic carcinomas induced locally by the administration of N-nitrosoacetoxymethyl-methylamine, N-methyl-N-nitrosourea, and methylnitro-nitrosoguanidine, or systemically by subcutaneous injection of 1,2-dimethylhydrazine in Sprague-Dawley rats. The endoscopic diagnostic examination proved to be clearly superior to methods of animal inspection, palpation, investigation for occult blood and exploratory laparotomy which have so far been employed in animal experiments with small rodents. The relevance of this method is discussed for the early detection of chemically induced colonic tumors, and the observation of tumor development under experimental cytostatic therapy.

Adenocarcinoma↗
PubMed1980

Extraovarian Brenner tumor. Case report and review.

We present the fourth case report of an extraovarian Brenner tumor, which was an incidental finding in a total hysterectomy 53-year-old woman. The morphology and pathogenesis of Brenner tumors are discussed.

Adnexa Uteri↗
PubMed1979

Occult blood testing using the guaiac method (haemoccult-test) for detection of tumorous lesions induced with 1,2-dimethyl-hydrazine and acetoxymethyl-methyl-nitrosamine in rats.

Colon tumors were induced by 1,2-Dimethylhydrazine (DMH) and Acetoxymethyl-methyl-nitrosamine (AMMN) in male Sprague-Dawley rats. The usefulness of the Haemoccult-test (HT) was investigated for early detection of these chemically induced tumorous injuries. As a prescreening method HT was shown to be unsuitable for early detection of tumours under the conditions of the models used. The accuracy of HT in cases of advanced chemically induced tumors was explored in rats with known colonic tumors, diagnosed by rectoscopy and exploratory laparotomy. In animals with proven colonic tumors HT gave a positive result only in 63% of rats with AMMN-induced tumors and in 50% rats with DMH-induced cancers. Therefore, HT is thought to be an insensitive and thus unsuitable method for the detection of colonic cancer in rats.

Adenocarcinoma↗