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Biomedical subjects

T Bartels

Publications and source records attributed to T Bartels.

51 records · Page 3Linked to original sources
PubMed1990

[Changes in the spongiosa density in the femoral head of rabbits in atherosclerosis].

Modulations of spongiosa density in the femoral head of rabbits by atherosclerosis. In a long-term study 31 rabbits (+5 control animals) were fed about 20 weeks on a diet rich in cholesterol. An important observation in this study was, that spongiosa density in the femoral head decreases after cholesterol rich diet in contrast to the control group. This effect could be modulated by the Trapidil AR 12463 content (50 mg/die) of the diet, but not by the high density lipoprotein application. Serum cholesterol levels and induced atherosclerosis were determined. Correlations between spongiosa density and atherosclerosis were discussed.

Animals↗
PubMed1989

[Prostaglandins--local regulators in bone?].

Since the initial discovery by Bergström, prostaglandin E has been the focus of an intense research effort in vitro and in vivo. The regulation of bone resorption and formation involves local as well as systemic factors. In the last decade, prostaglandins have been found to be intimately associated with bone metabolism. One hypothesis consistent that osteoblastic c AMP levels play a central role in determining whether osteoblasts stimulate or inhibit osteoclastic bone resorption. The osteoinductive properties of prostaglandins were discussed.

Animals↗
PubMed1989

[The significance of Ilmaplant as a bone substitute with reference to prostaglandin biosynthesis in bones. An animal experiment-clinical study].

The paper pointed out the resorbable material Ilmaplant-R and the glass ceramic Ilmaplant-L which are used for bone substitution. X-ray, histomorphometric and total mineral contents study were carried out in the region of healing defects in the tibia of 60 male white wistar rats. The healing response of the two bioceramics was compared 12 weeks after implantation. The inductive properties of prostaglandins were discussed. The possibilities of clinical application of Ilmaplant-R were demonstrated on the basis of short-term results up to 12 months.

Animals↗
PubMed1989

Histochemical study on the eccrine glands in the foot pad of the cat.

Enzyme and carbohydrate histochemical methods were used to study the secretory activities and secretion properties of the eccrine tubular glands in the foot pad of the cat. The activity spectra of the different oxidative and hydrolytic enzymes investigated indicate high metabolic rates within the secretory epithelium. Additionally the enzyme reactions emphasize a double innervation of the glands by cholinergic and adrenergic nerve fibres. The carbohydrate histochemical differentiation reveals mostly neutral and very few acidic glycoproteins in the secretory cells and the secretion, respectively. Clear (basal) cells contain distinct amounts of glycogen, and dark (superficial) cells show neutral glycoproteins, which reveal after PO-lectin-DAB procedures the following saccharide residues: alpha-D-mannose, alpha-D-galactose, N-acetyl-alpha-D-glucosamine, alpha-L-fucose, beta-D-galactose-D-N-galactosamine, beta-D-galactose, and sialic acid. The results obtained confirm the view that the normal biological functions of the eccrine glands of the feline foot pad are to improve the frictional capacities of the paw and to leave typical scent marks.

Animals↗
PubMed1988

Correlations between endogenous prostaglandin E formation in the bone and spongiosa density.

The formation of prostaglandin (PG) E in the femoral head and the lumbar vertebral body of rats under ex vivo conditions after a linoleic acid (LA) rich diet (13.3 J%) has been compared to that of rats after an LA poor diet (0.5 J%). LA rich diet increased the formation of PGE in the lumbar vertebral body. In the femoral head were a similar, but statistically insignificant effect. The spongiosa density in the femoral head and the lumbar vertebral body increased after LA rich diet in contrast to LA poor fed rats. We conclude that the spongiosa density could be modulated by the LA content of the diet possible via alterations of endogenous PG biosynthesis.

Animals↗
PubMed1986

Cardiovascular actions of dihydralazine as modified by dietary linoleic acid.

The experiments were carried out in order to examine whether the hypotensive effect of dihydralazine can be augmented by concomitant ingestion of a diet enriched with linoleic acid. After prefeeding with a linoleic acid rich diet (13.3 J%) an augmented hypotensive dihydralazine effect (11-24 mm Hg) could be observed in acute experiments in conscious (1 mg/kg i.v.) and pentobarbital-anaesthetised (4 mg/kg i.v.) normotensive rats with different duration of the feeding period as well as in conscious (1 mg/kg i.v.) spontaneously hypertensive rats relative to linoleic acid poor (0.5 J%) fed animals. This effect was abolished by pretreatment with the cyclooxygenase inhibitors indomethacin (10 mg/kg i.v.) or acetylsalicylic acid (100 mg/kg i.v.). The chronotropic dihydralazine response was with one exception not different between the two dietary groups. In chronic experiments with spontaneously hypertensive rats the augmentation of the hypotensive dihydralazine effect (1 mg/kg X d, s.c.) after linoleic acid rich diet did not attain statistical significance after a 6-weak prefeeding period. The renovasodilatory action of dihydralazine (3 mg) was increased in isolated kidney preparations of linoleic acid rich fed rats. This effect was accompanied by a shift of the prostaglandin formation toward vasodepressive PGE. We conclude that the altered cardiovascular effects of dihydralazine after linoleic acid rich diet are primarily caused by changes in the formation of prostaglandins and the activity of the sympathetic nervous system.

Animals↗
PubMedDate not supplied

Magnetic resonance imaging of intracranial tissue accumulations in domestic ducks (Anas platyrhynchos f. dom.) with feather crests.

The crested breed of domestic duck (Anas platyrhynchos f. dom.) has been described as a variety which has high pre- and postnatal mortalities, malformations in skull and brain anatomy, and several central nervous deficiencies. In addition, intracranial tissue accumulations have been diagnosed in purebred Crested ducks. The incidence, heredity and inheritance of these accumulations as well as their pathogenesis are still generally unknown. The aims of this study were to examine the head of Crested ducks, plain-headed duck breeds, and their crossbreeding relating to the incidence of intracranial alterations. These examinations were performed using magnetic resonance imaging. We found a high incidence of intracranial tissue accumulations in domestic ducks with feather crests. Creasted ducks had more intracranial tissue deposits than plain-headed ducks (p < 0.001). In the present study a correlation between the volume of the crest cushion and the volume of the intracranial tissue deposit could not be found (r = 0.014). Some of the Crested ducks had encephaloceles in addition to the crest cushion.

Adipose Tissue↗
PubMedDate not supplied

Experiments on an early protection against foot-and-mouth disease virus.

The influence of the peptide diacetylsplenopentin (SP5) on an early protection of guinea pigs against foot-and-mouth disease (FMD) was investigated. 80% protection was achieved if SP5 was applied in a dose of 2 mg one day before challenge with FMD virus (FMDV) type O1 Lausanne strain. In comparison with this a conventional commercial adsorbate vaccine protected guinea pigs about 7 days after vaccination. An earlier protection can be obtained in general by vaccination with a higher content of the immunogen. A tenfold increase of the 146 S particle dose in a conventional oil adjuvanted FMDV vaccine protected pigs about 2 days earlier as observed after inoculating a "normal" vaccine (about 11 days).

Adjuvants, Immunologic↗
PubMedDate not supplied

Liver-associated toxicity of the HSV-tk/GCV approach and adenoviral vectors.

Intravenous injection of immunodeficient mice with adenoviral vectors carrying the HSV-tk gene led to preferential transduction of liver tissue. Subsequent application of ganciclovir (GCV) resulted in extremely high toxicity with negligible survival rates. This toxicity was only seen when GCV was applied in addition to the adenoviral vector and not if combined with the Ad-beta gal control vector. This indicates a specific Ad-tk/GCV-related toxicity. Low survival rates were seen not only after intravenous administration but also after injection of the vectors into the portal vein, the liver tissue and liver tumors, but not during the treatment of subcutaneous tumors. This, together with extensive signs of liver degeneration occurring as early as one day after the initiation of GCV treatment, strongly suggests a specific liver-associated toxicity. Severe toxicity was observed when animals received GCV treatment as late as 7 weeks after vector administration. Moreover, in vitro survival rates of resting primary hepatocytes treated with Ad-tk and GCV were very low. We therefore suppose a mechanism of toxicity of phosphorylated GCV which is independent from cellular proliferation. Since our results indicate that the Ad-HSV-tk/GCV approach is toxic for the resting liver, additional safety features such as tumor-restricted transgene expression should be included in adenoviral vectors.

Adenoviridae↗