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Biomedical subjects

F Hartmann

Publications and source records attributed to F Hartmann.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Contrast-color Doppler echocardiography. Improved right heart diagnosis following intravenous injection of Echovist].

Flow patterns in the right heart are often difficult to visualize by color-coded Doppler flow imaging. The echogenicity of blood was increased in 48 patients by intravenous injection of 10 ml echovist (200 mg/ml), a saccharide solution with defined size and concentration of microbubbles. Its effect on improving color-coding was compared with the effect of agitated gelifundol (10 ml) in 21 patients with tricuspid valve regurgitation. The non-controlled size and concentration of microbubbles resulted in weaker or uncontrollably exaggerated color-coding in half of the patients. In eight normals biphasic atrial flow was visible only after injection of echovist. In 25 patients with tricuspid regurgitation the blue coded area of reflux was 25 +/- 21% of the atrial area from the parasternal approach and 10 +/- 9% from the apical approach without correlation of these results. After echovist the area of reflux was 57 +/- 31% (p less than 0.001) in the parasternal and 53 +/- 26% (p less than 0.001) in the apical approach (r = 0.83). This was paralleled by an increase of the severity of tricuspid regurgitation as defined by the length or area of reflux (p less than 0.01-0.001). The qualitative diagnosis was safely established in the five patients with VSD in the control color Doppler flow imaging, but only in three out of 10 patients with ASD, and in nine of 10 after injection of echovist. The intravenous injection of echovist, when using color-coded Doppler flow imaging for evaluation of right heart disease, facilitates the qualitative diagnosis of ASD and also of tricuspid regurgitation, particularly in the apical approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Intralesional interferon-alpha therapy in advanced malignant melanoma.

Fifty-one evaluable patients with histologically proven metastatic melanoma and at least one skin metastasis were treated intralesionally with interferon-alpha (IFN-alpha). Twenty-six of the patients were given highly purified natural IFN-alpha 6 Mio. IU three times per week. Twenty-five patients were given 10 Mio. IU three times per week of a recombinant IFN-alpha 2b (rIFN-alpha 2b). All patients were examined for systemic and local responses to this treatment. The systemic responses consisted of nine objective remissions, each of which lasted from 2 to 18 or more months. There were 24 complete or partial local responses. Forty-two of the 51 patients had at least two skin metastases so that IFN-injected and noninjected tumor sites could be compared. The difference between systemic and local efficacy was highly significant statistically (P = 0.0004). The results show that IFN-alpha has clinically observable antitumor activity in malignant melanoma.

Adult↗
PubMed1987

Generation of formaldehyde by N-demethylation of antipyrine. Detection of formaldehyde in bile by 13C-NMR spectroscopy.

The importance of NMR spectroscopy as a tool to investigate metabolic events in vitro and in vivo becomes more and more evident. Particularly 13C-NMR spectroscopy is able to deliver a wide range of information regarding the chemistry of xenobiotics in vivo. We studied the N-demethylation of N-methyl-13C-labelled antipyrine using an isolated perfused rat liver with a fluorocarbon suspension (FC 43) as oxygen carrier. Bile was collected in different fractions during the experiment. On the vascular side metabolite formation was monitored by continuous flow NMR spectroscopy. In bile the metabolic events were detected by standard NMR techniques. The bile spectra exhibit, among others, a signal at 84.2 ppm, indicating formaldehyde hydrate derived from the N-methyl group of antipyrine by an oxidative metabolic pathway. Neither formaldehyde hydrate nor other oxidation products could be detected in the vascular perfusate. The biliary excretion of considerable amounts of formaldehyde during the N-demethylation of antipyrine might have toxicological consequences for the intra- and extrahepatic bile ducts.

Animals↗
PubMed1987

[Isolated perfusion of the small intestine of the rat with perfluorotributylamine as an artificial oxygen carrier].

A new model of isolated intestinal perfusion could be established with fluorocarbon (FC-43) as artificial oxygen carrier. Morphology, cell metabolism of xenobiotics (phase I and II), as well as the transport of a monosaccharide, were stable for at least 2 h. Without interference with the changing metabolism of erythrocytes in the perfusion medium, the proposed model allows one to investigate exclusively the metabolic function of the perfused organ.

Animals↗
PubMed1986

Biomechanical properties of human intervertebral discs subjected to axial dynamic compression--influence of age and degeneration.

This investigation was performed to study biomechanical properties of human intervertebral discs as a function of age. 178 specimens from 21 spinal sections (Th9-S1, 5-84 yr) were subjected to axial dynamic compression; the load being 950 +/- 540 N. The results revealed three distinct age ranges: From the first to the middle of the third decade: axial deformability decreases within the thoracic region, and remains almost constant within the lumbar spine; creep decreases in both parts. From the middle of the third to the beginning of the sixth decade: the biomechanical behavior scarcely alters. Afterwards: axial deformability remains unchanged; creep, however, again increases within the lumbar spine. The results reveal the discs behave most efficiently within the age range where the incidence of back pain is maximal.

Adolescent↗
PubMed1986

Activation of latent collagenase from polymorphonuclear leukocytes by oxygen radicals.

Polymorphonuclear leukocytes (PMN) accumulating at inflammatory sites have the potential to degrade collagen by releasing the metalloproteinase collagenase (EC 3.4.24.7), which is stored within the specific granules of these cells in a latent, inactive, form. In order to elucidate the activation mechanism the latent enzyme (molecular weight 91,000) was purified from human PMN and incubated with the oxygen radical-generating system of xanthine oxidase (EC 1.1.3.22) and hypoxanthine. This coincubation resulted in the activation of the latent enzyme as assessed by the collagenolytic attack on human and bovine cartilaginous tissue. Two parameters for collagenolysis were used: loss of hydroxyproline-containing fragments, and mechanical measurements reflecting the stability of tissue specimens. Superoxide dismutase (EC 1.15.1.1) as well as catalase (EC 1.11.1.6) were capable of inhibiting the activation of latent PMN collagenase by the oxygen radical-generating system. The results indicate the hydroxyl radical to be the final oxidant responsible for the activation of latent PMN collagenase. Thus a new activation mechanism of latent collagenase is presented in this paper and discussed together with the potential relevance in pathophysiologic states of acute and chronic inflammation.

Animals↗