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Biomedical subjects

F Hartmann

Publications and source records attributed to F Hartmann.

At least 145 records · Page 8Linked to original sources
PubMed1984

Biomechanical behavior of human intervertebral discs subjected to long lasting axial loading.

48 lumbar discs were tested; the creep tests lasted between 2 and 6 hours. All discs showed the known creep behavior, i.e. a decrease of height, rate of creep and axial deformability with time. In the first minutes of a test the viscoelastic behavior quickly alters so that the disc behaves more like an elastic body. Loss of mass normally observed after creep tests is due to loss of water. Creep behavior is reproducible if a disc has sufficiently recovered, i.e. if it has regained its initial height. Creep tests on "desiccated" discs revealed that creeping is possible without loss of water and recovery is possible without absorption of water. The type of loading (static or dynamic) has hardly any influence on the biomechanical behavior. Our results indicate, that creep and recovery are chiefly due to extension and contraction of the anular fibers and not to fluid flow.

Adolescent↗
PubMed1982

Adrenocortical function of rats under prolonged administration of lipidosis-inducing drugs.

The influence of three potent lipidosis-inducing agents, i.e. iprindole, triparanol and chloroquine, on the rat adrenal cortex was investigated by determination of the corticosterone excretion in the urine, the responsiveness to ACTH and by determination of the corticosterone content of the adrenals and of the corticosterone concentration in plasma. Administration of iprindole and triparanol left the function of the adrenal cortex unaffected, while under chloroquine treatment an activation with time was observed. Morphologically, similar degrees of lipidosis were found in all experiments. The results demonstrate that the functional capacity of the rat adrenal cortex is not directly correlated to lipidotic alterations.

Adrenal Cortex↗
PubMed1982

Characterization of isolated epithelial cells from rat small intestine.

Intestinal mucosal cells from the rat have been isolated by a new technique involving intravascular perfusion of an intestinal segment with collagenase. Detached cells were flushed from the intestinal lumen with a second perfusion circuit containing an oxygenated buffered solution with 1% bovine serum. Sequential collection of cells at intervals during the period of perfusion revealed that villus-tip cells are recovered first (after 15 min of collagenase perfusion), followed by midvillus (after 25 min) and lower villus cells (after 35 min). The isolated cells were judged intact and viable by the criteria of trypan blue dye exclusion, ultrastructural appearance, and metabolic activity. They were characterized as villus-tip, midvillus, and lower villus-crypt cells by their alkaline phosphatase and sucrase activity, glycoprotein formation, and [3H]thymidine incorporation. Microsomal monooxygenase activity was four to five times greater in villus-tip than in lower villus cells, whereas heme oxygenase exhibited a reverse gradient. The isolated cells synthesized heme and bilirubin under cell culture conditions.

Alkaline Phosphatase↗
PubMed1982

Metabolism of heme and bilirubin in rat and human small intestinal mucosa.

Formation of heme, bilirubin, and bilirubin conjugates has been examined in mucosal cells isolated from the rat upper small intestine. Intact, viable cells were prepared by enzymatic dissociation using a combined vascular and luminal perfusion and incubated with an isotopically labeled precursor, delta-amino-[2,3-3H]levulinic acid. Labeled heme and bile pigment were formed with kinetics similar to those exhibited by hepatocytes. Moreover, the newly formed bilirubin was converted rapidly to both mono- and diglucuronide conjugates. In addition, cell-free extracts of small intestinal mucosa from rats or humans exhibited a bilirubin-UDP-glucuronyl transferase activity that was qualitatively similar to that present in liver. The data suggest that the small intestinal mucosa normally contributes to bilirubin metabolism.

Aminolevulinic Acid↗
PubMed1981

[Anabolic therapy in metastatic breast cancer].

The medical records of 66 women treated with metenolone for metastasized breast carcinomas were analysed. In 26 patients a remission developed with a mean duration of 8.2 (3-29) months. Patients whose treatment started in the first year after the menopause as well as patients with a beneficial effect of a therapeutic ovariectomy in the past were more often improved by metenolone than average. Metenolone had a better effect against osseous metastases than against visceral metastases. In most cases the treatment was well tolerated. In four patients, however, the treatment had to be interrupted because of cholestasis, pulmonary embolism and hypercalcaemia.

Adult↗
PubMed1981

[Renal hypertension in aortic stenosis].

Report of the clinical, biochemical, hemodynamic and x-ray data of a girl, 16 years of age, who had a narrowing of the abdominal aorta (diaphragmatic type). The stenosis was proximal to the renal arteries and was associated with unobtainable arterial pressure in the lower extremities and with hypertension in the arms. Although mechanical factors seemed to play the primary role in the production of hypertension, a further important factor inducing hypertension was the activation of the renin-angiotensin-aldosteron-system caused by reduced renal circulation.

Adolescent↗
PubMed1981

[What role does secondary hyperaldosteronism play in decompensated liver cirrhosis?].

In 29 untreated resting patients with cirrhosis of the liver and ascites plasma aldosterone levels were determined. The determinations were performed with a radioimmunoassay using highly specific antibodies without chromatography. Seven aldosterone values were decreased, 18 were normal and only four were increased. The median of the values was 107 pg/ml and differed not from that of healthy persons. In 20 other patients, in which application of diuretics had already been started, 14 plasma aldosterone levels were increased. The median was 332 pg/ml und thus far above the normal range. Secondary aldosteronism in connection with decompensated cirrhosis of the liver arises mainly under therapy with diuretics.

Aldosterone↗
PubMed1981

[The deformation behavior of human lumbar intervertebral discs subjected to long term axial dynamic compressive forces (author's transl)].

49 specimens were studied in 67 axial compression tests; the duration test varied between 2 and 6 hours. All discs showed marked creep; after a big decrease in the first minutes the rate of creep decreases still slightly. Additional the results reveal a decreasing axial deformability with time. In the beginning of a test quickly the viscoelastic behavior alters to such a steady state that the disc behaves more like an elastic body. Loss of mass normally observed after compression tests is due to loss of liquid, but liquid absorption during mechanical load is possible too. The long term biochmechanical behavior is reproducible very well; a second experiment done with the same disc yields nearly the same results.

Adolescent↗
PubMed1981

[Computer-based measurements of bladder cancer urothelial cells by high-resolution microscopic-cytophotometric system (author's transl)].

Examination of exfoliated urothelial cells present in the urine has been shown to be diagnostic by many researchers, but cytology is not yet widely accepted for routine diagnostic purposes. Cytology is highly efficient in the primary diagnosis of high grade transitional carcinoma (grade II-III) but of limited value in the diagnosis of benign papilloma and low grade tumors. The sensitivity of cytology would be increased by improving the techniques of collecting cells out of urine, using highly sensitive staining techniques and by objective cytologic measuring methods. Using a computer-based cytophotometric microscope, the cytologic analysis of 26 patients with bladder tumors are represented. There is evidence that a computerized measuring system is able to detect bladder tumors with a high accuracy.

Carcinoma, Transitional Cell↗
PubMed1981

Clinical application of corticoids.

Corticoids given therapeutically may interrupt the loop on feedback mechanism by which plasma cortisol levels are controlled. This was demonstrated when corticoids were applied to the skin in the treatment of dermatoses and when taken by mouth the patients with polyarthritis. In rats, Endomethasone root fillings has similar effect. Corticoids applied to the gingiva or instilled into periodontal pockets did not lower group mean plasma cortisol levels but individual patients did show suppression of cortisol secretion. It is concluded that all corticoids, no matter how applied, will have this effect, although present analytical methods may be too insensitive to detect the smaller changes.

Administration, Topical↗