Biomedical subjects

E Ratzenhofer

Publications and source records attributed to E Ratzenhofer.

13 recordsLinked to original sources

PubMed1985

Structural changes of hair after incorporation of the proline analogue L-azetidine-2-carboxylic acid. A model of hair disease by alteration of primary structure.

In order to correlate biochemical changes of the hair with physical properties we present a model for the examination techniques. L-azetidine was incorporated into the hair keratin complex and the resulting mechanoelastic properties were determined using the ultramicrohardness testing system on scanning electron microscopy. Structure was investigated by X-ray diffraction and incorporation of L-azetidine was detected by thin-layer chromatography. This system could possibly be introduced for examination of hair changes in humans. 8 white mice, 3 weeks of age, were given L-azetidine-2-carboxylic acid in water (0.1 g/100 ml) as only source of fluid over a period of 5 weeks. They had free access to dry mouse cake only. 8 animals of the same strain, who had free access to tap water and mouse cake and were kept under the same conditions, served as controls. After 5 weeks, the animals were sacrificed and hair was obtained for analyses. 2 dimensional thin-layer chromatography of hair hydrolyzed with 6N HCl at 105 degrees C for 12 hours revealed 2 additional spots in the chromatographic pattern in the experimental animals in comparison with the control group. 1 of the spots was identified as L-azetidine-2-carboxylic acid, while the second spot was possibly a degradation product of L-azetidine on acid hydrolysis at a high temperature. Hair of the animals was put into Mark capillaries and subjected to X-ray diffraction, which showed a markedly disordered orientation of keratin. Impression studies using scanning electron microscopy revealed a remarkably reduced elasticity of hair with incorporated L-azetidine. These findings may be explained on the basis of qualitative or quantitative changes in the helical structure of the keratin complex of hair, which is responsible for the elastic properties, whereas the globular matrix is responsible for the firmness of the hair.

Animals↗

PubMed1984

[Incorporation of L-azetidine-2-carboxylic acid into collagen of the skin. Structural changes].

As previously shown by two dimensional thin-layer chromatography L-azetidine-2-carboxylic-acid (L-Az) is incorporated into type I skin collagen instead of proline when 3 week old mice are fed with a 0,1% solution of L-Az orally. Ultrastructural investigations did not reveal significant changes in collagen periodicity and on fibril diameter. The collagen fibrils of the upper papillary dermis seemed to be packed more densely, sometimes only one electron dense lamina was seen instead of basal lamina and plasma membrane. The glycosaminoglycane-induced fibrillogenesis was not changed in contrary to the collagen-heat-gelation fibrillogenesis at 37 degrees C, where no gel aggregation could be seen. The reconstruction of native fibres from collagen solutions was disturbed too, several finer precipitated fibrils being detectable. On infrared spectroscopy significant differences in absorption spectra were detected. Correlating with previous results of reduced tensile strength and normal melting point of L-Az collagen we can conclude that L-Az might cause rather intermolecular than intramolecular disturbances of crosslinking.

Animals↗

PubMed1983

[Manifold reflection infrared spectroscopy of the hair of mice with an experimental amino acid metabolism disease (L-acetidin-2-carboxylic acid incorporation instead of proline). A model for the use of infrared spectroscopy as a screening method for metabolic diseases].

8 mice were given L-acetidin-2-carboxylic acid orally over a period of 5 weeks. Another 8 mice served as control animals. Finally, the mice were sacrificed, their hair samples were hydrolized and applied to thin layer chromatography which revealed the incorporation of L-acetidin-2-carboxylic acid into mouse hair expressed by an additional spot. This experimental amino acid metabolic disorder served as a model for the application of infrared spectroscopy for screening hair in order to check metabolic disorders. As the multiinternal reflection-infrared spectra showed significant differences we suggest that infrared spectroscopy can be used as a noninvasive screening technique.

Amino Acid Metabolism, Inborn Errors↗

PubMed1983

[Incorporation of L-acetidine-2-carboxylic acid in type I skin collagen. Biochemical and mechanoelastic properties].

In order to elucidate the role of L-acetidine-2-carboxylic acid (L-ac) incorporated into collagen type I of the skin instead of proline, we looked for the mechanoelastic properties of skin. Mice were orally fed with 0, 1% solution of L-ac for 5 weeks, then sacrificed, and type I collagen was extracted. Incorporation of the proline analogue (L-ac) could be shown by two dimensional thinlayer chromatography. The melting point (Tm) of type I collagen was determined by circular dichroism: 36, 5 +/- 1 degrees C for normal collagen, 37 +/- 1 degrees C for L-ac-collagen. This insignificant difference indicates that there was no alteration of the thermal stability of the collagen helix after incorporation of L-ac. Tensile strength was examined on whole strips of skin and worked out at means = 1,00 N/mm, s = 0,20 N/mm, sigma = 0,04 N/mm for normal individuals and means = 0,62 N/mm, s = 0,24 N/mm, sigma = 0,05 N/mm for L-ac-fed animals. The considerable difference could be estimated by the Wilcoxon test (p less than 0,005). As the stability of the collagen helix (shown through melting point determination) has not decreased, the reduced mechanoelastic property of tensile strength seems to be due to intermolecular rather than to intramolecular disturbances of the cross connection of the triple helix.

Animals↗

PubMed1982

[Epithelioma cuniculatum. A special form of verrucous carcinoma (author's transl)].

The case report is presented of a patient with epithelioma cuniculatum, which developed on the sole of the foot following a poorly-healed war injury sustained years previously. The histological picture was that of a well-differentiated, locally invasive squamous cell carcinoma. It must be distinguished from other verrucous carcinomas in the differential diagnosis.

Amputation, Surgical↗

PubMed1982

[Non-enzymatic glucosylation of proteins].

The modification of haemoglobin A by glucose to haemoglobin A Ic is a classical example for a nonenzymatic glucosylation (n. e. glu.) reaction of a protein. It has been suggested, that various proteins are subjected to this process during hyperglycemia phases, if the protein meets certain steric, electrostatic and biochemical characteristics. In the present report n. e. glu. of haemoglobin, serum protein, collagen, basement membrane protein and alkaline phosphatase is discussed. It is suggested that n. e. glu. might influence protein function and forms thus the biochemical basis for specific complications of diabetes mellitus in an outside pregnancy.

Adolescent↗

PubMed1981

[Linear epidermal nevus with multiple malformations. (author's transl)].

We report about a 12 year old boy who was born with a linear epidermal nevus. This nevus extended from the umbilicus strictly along the midline to the symphysis and continued on the right leg caudally to the medial brim of the foot and the first and second toe. Changes of bone structure are seen at-x-ray examination of the right hip and leg. Vascular dysplasia with arteriovenous shunts and spinal angiomas were found by angiography in the vascular bed of the left iliac artery. The length of the legs differed due to hyperplasia of the left lower extremity and both feet resembled the "Friedreich-foot".

Abnormalities, Multiple↗

PubMed1980

Evidence of H2 receptor activity on glomerular cells.

The role of histamine in physiological and pathological states has not been fully elucidated. In the pathological state histamine release can be induced by several mechanisms. The most frequent events are IgE-mediated release, complement-mediated release and release by chemical agents. During inflammation histamine is set free and contributes to the course of inflammatory processes, either enhancing or inhibiting inflammatory reactions. In order to look for a target in the glomerulum we examined H2 receptor binding to isolated glomerular cells using 3H-cimetidine as ligand. Two binding sites were detected, a low affinity site with a kD = 6.3 microM and a high affinity site exhibiting a kD = 0.18 microM. These findings are comparable to properties of 3H-cimetidine receptor binding to brain membranes.

Animals↗

PubMed1979

[Excretion of acid mucopolysaccharides in the urine and sweat in hereditary bullous epidermolysis].

Urine samples of five patients with epidermolysis bullosa hereditaria were examined for the presence of acid glycosaminoglycans (GAG) and compared to 10 healthy subjects. A significant increase (p less than 0.0005) could be detected in patients with epidermolysis (t = 6.66, means: 49.7 mg/day, standard deviation: +/- 18.3). Additionally, acid glycosaminoglycan concentration in sweat of patients and healthy controls was determined but statistical calculations showed no significant difference (p less than 0.15). On grounds of the increased mucopolysaccharide excretion and the previous studies of collagen-glycosaminoglycan interactions, we strongly suggest that acid GAG are involved in the pathogenesis of that disease with the molecular defect of disturbed fibril formation due to the altered skin collagen-glycosaminoglycan equilibrium.

Adolescent↗

PubMed1979

Collagenase activity of rat kidney with glomerulonephritis is inhibited by erythromycin.

Collagenolytic activity of rat kidney with glomerulonephritis (GN) of Masugi's type was determined by a series of biological experiments. The determination was carried out during the heterologous phase of the disease together with inhibition studies in vivo and in vitro. Erythromycin has been tested in vivo for its inhibitory activity and an activity of collagenase was found in untreated rats with GN only, the panel treated with erythromycin did not show any collagenolysis. Statistical calculations indicate the significance of the inhibition (p less than 0.001). In addition, kidneys of test animals with GN have been investigated for their enzymatic activity and the inhibition by erythromycin in vitro where the kidneys failed to show collagenolytic activity. It can be concluded that erythromycin is able to inhibit in vivo and in vitro the activity of the collagenolytic enzyme produced by polymorphonuclear leukocytes during the heterologous phase of the nephritis, an effect which leads to the recovery of the physiological equilibrium of the protease and its inhibitor.

Animals↗

PubMed1978

[In-vitro inhibition of collagenase activity in epidermolysis bullosa hereditaria dystrophica].

By means of a biological collagenase assay we estimated collagenolytic activity of the vesicular fluid of patients with epidermolysis bullosa hereditaria dystrophica. All the 5 examined patients showed increased collagenolysis. Inhibition studies were performed applying ethylendiaminetetraacetate inhibition 11,15%, normal human serum in 12.15% (means). o-Phenanthroline as well as erythromycine in an aequimolar ratio stopped the collagenolytic activity completely in the 5 specimen. It was the aim of our study to indicate that erythromycine, in contrast to other collagenase inhibitors relatively atoxic, is able to inhibit collagenase activity which is suggested to play a pathogenetic role in that disease.

Adult↗

PubMed1978

Collagenase activity of rat kidney with immune complex glomerulonephritis.

By means of a biological assay the collagenolytic activity of kidneys from rats with experimental immune complex glomerulonephritis and control animals was tested. We detected collagenolysis in both panels but found quantitative differences in the collagenase activity. The enzymatic collagenolysis was significantly increased (P less than 0.001) in the nephritic kidneys. From the fact that the chelating agent EDTA inhibited potentially the released enzyme it can be concluded that the origin is the polymorphonuclear granules.

Animals↗

PubMed1977

[Vesicular fluid of hereditary bullous dystrophic epidermolysis splits alpha 1-antitrypsin].

In epidermolysis hereditaria bullosa dystrophica increased collagenase activity can be detected and seems to be one of the pathogenetic mechanisms of this disease. Neither the origin nor the mechanism of increased collagenolysis is known. Whether the cause of the enzymatic imbalance is the increased collagenase production or decreased collagenase-inhibitor activity cannot be decided. Factors of decreased protease inhibitor activity could be the quantitative or qualitative defect or the inactivation of the inhibitor. Clear, sterile vesicular fluid was incubated with alpha-1-antitrypsin, which is known to inhibit collagenase. By means of an immunoelectrophoretic method the cleaving of the inhibitor into two antigenic split products was found. We suggest that this might be responsible for the increased collagenolysis in this form of epidermolysis.

Child, Preschool↗