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Biomedical subjects

W Bauer

Publications and source records attributed to W Bauer.

At least 37 records · Page 2Linked to original sources
PubMed1993

SDZ CO 611: a highly potent glycated analog of somatostatin with improved oral activity.

To obtain orally active octreotide (Sandostatin, SMS 201-995) analogs a new class of glycated somatostatin derivatives were synthesized by the Amadori reaction (Maillard reaction). The synthesis, chemical and biological characterization of a series of new compounds is described. These oligopeptides bind with high affinity to somatostatin receptors and retain full biological activity. Whereas generally polypeptide hormones are almost completely inactive after oral administration, we report here for the first time that these analogs show remarkably high activity by the oral route. Thus for example SDZ CO 611, the D(+)-maltose Amadori derivative of octreotide, has about 10 times higher oral effect bioavailability than octreotide while maintaining the selectivity, metabolic stability and long duration of action of the parent compound.

Administration, Oral↗
PubMed1992

[Space closure with T loops (Burstone)--a clinical study].

The theoretically favourable aspects of orthodontic space closure with segmented arch technique and the T-loop type A are clinically reproducible. In our study of eleven patients we found for the isolated canine retraction, as well as for the en masse retraction, controlled types of movement for the active units and maximum anchorage situations for the passive units produced by the torquing force. Because of these good anchorage conditions space closure could be done without headgear. The level of the anchorage segments was negligibly influenced but in the anterior segments a marked tilting was found in several cases. Besides other factors the intrusive force of the T-loops type A must be considered. As a rule the positioning of the T-loop between central and lateral incisor is to be recommended.

Activator Appliances↗
PubMed1991

Identification and determination of the two principal metabolites of minocycline in humans.

A chromatographic method has been developed for the quantification of minocycline in human serum and urine. The chromatographically determined concentration of minocycline correlated well with the microbiologically active concentration in serum. Two metabolites, 9-hydroxyminocycline and N-demethylated minocycline, could be isolated and identified as the principal metabolites of this tetracycline antibiotic. The structure of the 9-hydroxy compound was proved by nuclear magnetic resonance analysis for the first time. About 15% of the drug was actively converted in the body into a substance less microbiologically active than the parent compound and excreted in the urine within 96 h after the application.

Adult↗
PubMed1991

[Tooth germ transplantation or gap closure--a comparative study in the loss of the first molar].

In our study 37 transplanted and 33 mesialized molars by orthodontics were clinically and radiologically compared. The teeth moved by orthodontics showed a better long-term prognosis. As vital teeth with functioning periodontal structures and only slightly shortened roots they were equivalent to healthy teeth. However, the disadvantage of orthodontic space closure is the requirement of a good compliance due to long treatment time. The prognosis of maintaining a transplanted tooth germ is uncertain. One third of the teeth showed an altered periodontium with resorption areas. The danger of a continuing resorption, as well as a late external resorption is still a risk after a long period of time and can eventually lead to tooth loss. As a treatment alternative, germ transplantation may serve as a replacement of a single missing 6-year-molar in adolescence. Orthodontic space closure is indicated at any age with an existing dysgnathia, the loss of several first molars, the loss of space and mesial tipping of the second molars.

Adolescent↗
PubMed1991

Expression of class II molecules on intestinal epithelial cells in humans. Differences between normal and inflammatory bowel disease.

Expression of class II antigens on human intestinal epithelial cells was assessed using a sensitive avidinbiotin-peroxidase technique. HLA-DR was present predominantly in the normal small bowel with diminished but evident expression in the colon. HLA-DP staining was less prominent, and HLA-DQ was absent. In inflammatory bowel disease the expression of both HLA-DR and HLA-DP was increased, but that for HLA-DQ remained absent, suggesting an inherent defect in the ability of intestinal epithelial cells to express HLA-DQ. In related experiments, an interferon gamma-treated malignant epithelial cell line T84 also failed to stain for HLA-DQ and HLA-DP despite the presence of HLA-DR. Isolated RNAs for all three subclasses of HLA-D were detectable by slot-blot analysis, suggesting that the lack of HLA-DQ expression relates to posttranscriptional defects in intestinal epithelium. These and other differences with conventional class II antigen-positive accessory cells (macrophages/B cells) may help to explain the unique properties of intestinal epithelial cells as antigen-presenting cells.

Adenocarcinoma↗
PubMed1991

Effects of endothelin-1 in the isolated heart in ischemia/reperfusion and hypoxia/reoxygenation injury.

The effects of the vasoconstrictor peptide endothelin-1 were examined in the isolated heart during hypoxia, reoxygenation and reperfusion. Isovolumic rat hearts were perfused with Krebs-Henseleit buffer at constant pressure. Cumulative dose-response curves were obtained for endothelin-1 boluses of 0.04 to 400 pmol in five groups of hearts. Coronary flow declined with increasing dosages and was almost abolished at 400 pmol in control hearts. In hearts subjected to mild hypoxia (perfusate PO2 approximately 150 mmHg), the constrictor effect of endothelin-1 was attenuated at moderate dose compared to control hearts (4 vs. 16% flow reduction at 40 pmol; P less than 0.05). The constrictor effect was unaltered in hearts subjected to either 60 min of severe hypoxia (PO2 approximately 35 mmHg) followed by reoxygenation or to 10 min of total ischemia followed by reperfusion (stunning). When hearts were reperfused following 30 min of total ischemia (irreversible injury), the constrictor response to endothelin-1 was potentiated compared to control (e.g. 36 vs. 16% flow reduction at 40 pmol; P less than 0.05). We conclude that endothelin-1 is a potent coronary constrictor in hypoxic, reoxygenated and reperfused heart. The constrictor effect is attenuated during hypoxia, most likely due to the presence of counteracting vasodilator metabolites. During reperfusion, the constrictor effect is unchanged in stunned myocardium, but is augmented in irreversibly injured heart, due to either increased endothelin-1 binding sites or loss of counteracting vasodilator mechanisms such as prostaglandins and/or endothelium-derived relaxing factor.

Animals↗
PubMed1991

[Clinically relevant biomechanics. 3. Critical reflections about the Burstone intrusion mechanics].

A segmented arch for intrusion of front teeth, as described by Burstone, is compared to a coil-and-stylus-model. The mechanics of constructive modifications are analyzed and their consequences for the movements of front teeth are discussed. It is shown, that in some cases extrusive forces occur, while intrusive forces are applied. In these cases it is necessary to reduce intrusive forces below 0.20 Newton per side. In order to avoid extrusive forces, it is recommended to apply intruding forces between the centers of resistance of the central and lateral incisors.

Dental Stress Analysis↗
PubMed1991

[Limitations of intrusion of periodontally involved maxillary buccal teeth for furcation treatment].

In a study on three dogs 12 two-rooted premolars with reduced periodontia were intruded to reestablish marginal attachment. In eight roots intrusion into the basal cortical bone of the nasal sinus was found. The histological findings showed that in these cases a possible gain of new attachment in the interradicular space may be impaired by a loss of bone support in those sites where the root intruded into the sinus. The greater the extent of intrusion into the sinus the higher the expected loss of periodontal attachment.

Alveolar Bone Loss↗
PubMed1991

Percutaneous radiofrequency thermolesion of the sympathetic chain in the treatment of peripheral vascular disease.

Percutaneous radiofrequency thermal lesion of the lumbar sympathetic chain (PRFS) was performed in 30 patients with diabetes mellitus suffering from unreconstractable endstage peripheral vascular disease. All of the patients had the feeling of warmth after PRFS, 45% were free of further complaints and 63% changed to stage II according fontaine. The reported data demonstrate a good comparability concerning amputation after a period of two years to the results obtained by surgical sympathectomy. As there is no need of general anesthesia PRFS turned out to be a good alternative to the surgical sympathectomy.

Adult↗
PubMed1990

[The motivation and assessment of the success of adult patients undergoing orthodontic treatment--the interpretation of a questionnaire].

In order to analyze orthodontic treatment of adults concerning information, motives and retrospective evaluation 225 patients with fixed appliances were questioned. The dentist had a key position as a mediator of information. The decision to an orthodontic treatment was led by esthetic and functional motives. The extent of the respective motives depended from age, personal status, education and cooperation. Interest and understanding in functional improvements as they could be found above all by people with a higher education level were decisive for a durable regard of the treatment.

Adult↗
PubMed1990

[The effect of the maxillary sinus floor on orthodontic tooth movement].

By superimposing 40 pre- und post-therapeutic orthopantomograms the degree of tipping and kind of movement of 87 teeth could be described quantitatively, dependent on configuration and extension of the basal maxillary sinus. It has been shown that, with a more vertical extension (VL = 1) in front of the tooth to be moved one can expect an obviously higher degree of tipping (about 10 degrees) as compared to teeth moved through a more horizontal maxillary sinus base (VL = 2). In the group of teeth VL = 1 a correlation between the depth of the maxillary sinus recessus and the degree of tipping could be found (p less than or equal to 0.05); i.e. the deeper the maxillary sinus recessus, the higher the degree of tipping. For VL = 2 this correlation is statistically not significant. In the group VL = 1 rather a tipping movement, in VL = 2 a translatory movement can be expected.

Adult↗
PubMed1990

[Experimental bodily tooth movement through the bony floor of the nose--a pilot study].

Our experiment on animals was carried out in order to show to which degree the dog's bony nasal floor--taken as an equivalent of the recessus of the human maxillary sinus--is an obstacle to bodily tooth movement. The metric analysis showed that the movement of the upper teeth in comparison with the teeth of the lower jaw was markedly impaired by the basal cortical bone of the cavum nasi. Extended resorption of the basal bone of the nose was found histologically. The pressure side of the root surface too showed resorption lacunae which reached into the dentine deeply and were bordered by some osteoclasts.

Animals↗
PubMed1989

Clinical and histopathological considerations for the diagnosis and treatment of verrucous carcinoma of the larynx.

Verrucous carcinoma of the larynx is quite distinct from well-differentiated squamous cell carcinoma has a characteristic morphology and specific clinical behavior. It accounts for approximately 1%-2% of all laryngeal carcinomas. However, difficulties are encountered clinically in separating verrucous carcinomas from keratoses, verruca vulgaris and squamous cell carcinomas with a verrucous appearance. Between 1962 and 1982, 1504 patients with squamous cell carcinomas of the larynx were diagnosed and treated by staff physicians in the Department of Otolaryngology--Head and Neck Surgery, Washington University in St. Louis. Fifteen of these patients (1%) had verrucous carcinomas. These cases were studied in order to clarify any diagnostic problems, trace the biologic behavior of the tumors and report the results of the treatment used. Of these 15 patients, we were able to follow up 8. The latter had been treated only with surgery and none of them had received radiotherapy. One death occurred, but the patient died of other causes and remained free of cancer. Reports in the literature describe a high rate of recurrence of verrucous carcinomas following radiotherapy with occasional anaplastic transformation of tumors. No patients in our series developed a metastasis in the neck, indicating that neck dissection is not justified for patients with these neoplasms even though clinically enlarged neck nodes may be present.

Adult↗
PubMed1988

Structure-function relationships of somatostatin analogs.

Objective of peptide chemistry has always been the production of analogues for clinical application. Advantages sought over natural peptides are (a) reduced molecular size; (b) prolonged biological half-life, and (c) enhanced specificity. After elucidation of the active core of somatostatin a number of analogues have been synthetized. Among them SMS 201-995, an octapeptide, was selected for further development because of its high potency and prolonged plasma clearance. Procedures extending the duration of action of somatostatin derivatives such as enhancement of lipophilicity and amino acid substitution are described, and factors influencing the specificity of such substances are succinctly analyzed.

Animals↗