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Biomedical subjects

D Schumann

Publications and source records attributed to D Schumann.

At least 37 records · Page 2Linked to original sources
PubMed1994

Formation, derivatization and applications of bacterial cellulose.

Acetobacter xylinum produces highly crystalline cellulose extracellularly using glucose as a carbon source. The polymer formed is free of other biogenic compounds, separable in a simple way and characterized by its high water-absorption capacity. Stepwise solvent exchange from water to unpolar solvents leads to a drastic decrease of the water content of the bacterial cellulose without decrease of the highly swollen and activated state. Heterogeneous as well as homogeneous derivatizations, e.g. carboxymethylation, silylation and acetylation, were performed on the wet or dried biopolymer. Furthermore, different methods for formation of hollow fibres during biosynthesis were investigated. Such tubes may have applications as biocompatible material in medicine.

Absorption↗
PubMed1994

Health risks for women with breast implants.

Women who have undergone implantation of a breast prosthesis have been exposed to a variety of health risks, many of which were unknown to them at the time of surgery. Recognition of health hazards has prompted the Food and Drug Administration to restrict implantation of these devices while study of safety and efficacy are undertaken. Capsule contracture, or the contraction of the fibrous tissue surrounding the prosthesis, is the most frequently occurring complication. Exposure to an implant does not appear to heighten the risk for breast cancer, but the opacity of a prosthesis substantially reduces the diagnostic capability of mammography. Silicone, used in the manufacture of implants, is linked to immunologic changes that result in connective tissue disorders. Most often this condition is scleroderma. Damaging effects from toluenediamine, a disintegration product of the polyurethane coating, have been reported. Whether the concentration of this chemical reaches toxic levels in women with prostheses remains to be clarified by current investigations.

Breast Implants↗
PubMed1992

Cytokeratin pattern of clinically intact and pathologically changed oral mucosa.

The various cytokeratin polypeptides in oral epithelia are expressed in dependence on site and formation of a stratum corneum. Certain cytokeratins occur permanently and others occasionally. In fibrous hyperplasia and Lichen ruber planus, patterns of cytokeratins did not deviate significantly from normal. In some but not all cases of squamous cell carcinoma and leukoplakia studied, marked aberrations of pattern were characterized by (i) appearance of cytokeratin No. 19, (ii) somewhat more frequent occurrence of cytokeratins Nos. 8 and 18, (iii) proteolytic modifications of cytokeratins, and (iv) partial loss of a few site-specific cytokeratins. The aberrations may be taken as additional diagnostic criteria for differentiation between non-aggressive and potentially aggressive leukoplakic lesion, even if they are not correlated with the conventional histological grading of dysplasia.

Adolescent↗
PubMed1992

Tissue expansion in pig skin--a histochemical approach.

In the present study, a porcine model for controlled skin expansion was investigated to improve our understanding of epidermal and vascular responses following stretching. The model is of outstanding importance not only for the clinical use of tissue expansion but provides interesting data for skin physiology and oncology, too. Thirteen out of 15 animals, who underwent silicone tissue expander implantation showed good clinical results. In all of them, skin biopsies were taken at the end of a controlled tissue expansion procedure (final expander volumes 350 or 500 ccm): one tissue specimen was obtained from the centre of the expanded skin area and a second from the neighbouring but nonexpanded skin. The tissue specimens were immediately frozen in liquid nitrogen and processed to 4 microns thick acetone-fixed frozen sections. Lectin histochemistry and immunohistology were performed using the following techniques: direct and indirect immunofluorescence technique (DIFT, IIFT), immunoperoxidase technique (POX) with either 3,3'-diamino-benzidine (DAB) or 3-amino-9-ethyl-carbazole (AEC). The histochemical findings were supplemented by measurements of the number of vital epidermal cell layers, the epidermal thickness (microns), and the papillary vascular count per visual field. There was a significant diminuation of the vascular count (mean +/- S.D. = 55.0% +/- 12.5%; U-test: p less than 5%). By immunohistochemistry, a loss of the basal cell reactivity for the following antibodies was noted: ACAM (against calmodulin), K 8.12 (against keratins 13 +/- 16) and A51-B/H4 (against keratins 8, 14, 18). There was a remarkable increase of filaggrin expression in the uppermost spinal cell layers in expanded skin, which was most pronounced in those specimens with the shortest interval to the last fluid injection into the expander. We gained no evidence for alterations of the expression of suprabasal epidermal keratins, lectin binding sites (UEA I, PNA, ConA, WGA), and vascular lectin- and immunoreactivity due to tissue expansion. The subdermal capsule, which had formed around the silicone expander, was strongly vimentin-reactive. In conclusion, controlled tissue expansion is capable to change the basal cell phenotype--a feature which is shared with a number of conditions with increased proliferative activity and with the epidermis covering different skin tumours. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation. Furthermore, the porcine skin is a reliable model for studying physiology and pathophysiology of human skin.

Animals↗
PubMed1992

FDA and ADA evaluation of dental implants.

The FDA classification of endosseous dental implants (EDI) is reviewed. Factors impacting the long-term efficacy of dental implants and the guidelines for development of EDI are enumerated. The role of the ADA in evaluation of EDIs is also discussed. Recommendations for development of performance criteria and reporting format are made.

American Dental Association↗
PubMed1992

[Maxillary development after early secondary osteoplasty in complete unilateral cheilognathopalatoschisis].

The paper presents the retrospective investigation of 99 cleft palate cases with unilateral clefts. The effects of two different lip closures procedure on the development of nasal, labial and maxilla region were investigated. In 50 cases the Le Mesurier lip closure procedure was followed, and in 49 cases the Millard procedure. In the Le Mesurier group a lengthening of lip was observed, while in the Millard group lip length was symmetrical. The cast analysis shows an even development of the anterior maxilla width. The cephalometric analysis also shows a favourable development in the Millard group.

Adolescent↗
PubMed1992

[An examination of the prognostic value of biological parameters exemplified by the crucial prognosis-relevant factors of the TPI in the patient load of the Jena Clinic in 1968 to 1991. Therapy-dependent Prognosis Index].

The data of 240 patients with non-pretreated oral squamous cell carcinoma were analyzed in dependence on the tumor size (T-category), on the histologic checked lymph node status and the histopathologic grade of malignancy. There is a conformity to the results published by the DOSAK regard to the tumor size (T-category). The comparison of the survival of our patients with the estimated survival rate of the TPI shows also conformable results. Differences exist in the prognostic valuation of the lymph node status by the DOSAK. The histologic verificated lymph node status and the malignancy grade will recommend as decisionsive prognostic relevant parameters.

Aged↗
PubMed1992

[Experimental studies on tissue expansion in reconstructive surgery].

In the present study, a porcine model for controlled tissue expansion was investigated under the conditions or formation of extreme enlarged randomized flaps. The circulatory disturbances and necrotizing processes to be expected were evaluated immediately after flap formation by intravenous injection of fluorescein dye to predict the surviving area. Lectin histochemistry and immunohistology were performed using either the direct and indirect immunofluorescence technique (DIFT, IIFT) or immunoperoxidase techniques (POX). Over all, the expanded randomized flaps healed without complications in all animals. The acute randomized flaps showed clear necroses already after 10 days. In the thoracic area they averaged 60.3% (SD = 8.17%) and in the pelvic area 47.32% (SD = 14.11%) of the flap. The use of the fluorescein dye test in the present experiment demonstrated that the flap surviving area is significantly greater than the flap staining area. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation.

Animals↗
PubMed1992

[Late results of breast augmentation].

Late results of augmentation mammaplasty with dermis fat transplants and implants are presented and discussed separately. With correct handling and strict indication a mammary implant heals in without complications and with good results. The problem of capsular fibrosis is discussed. Prerequisites for augmentation mammoplasty are detailed information about and strict selection of candidates.

Adipose Tissue↗
PubMed1991

[Qualitative and quantitative studies of the inflammatory reaction in the tumor boundary zone of intraoral squamous cell carcinomas].

The inflammatory cellular infiltration in the tumor boundary zone was analyzed in 10 primary tumors, completely histologically worked up and not pretreated, using a metric and reproducible evaluation system at a line of 10 cm per case. The part of the tumor boundary zone free of inflammation varied between 2% and 79%, where as only 3 of the examined 10 tumor cases showed actions free of inflammation under 10%. In the differential cell picture of the inflammation the lymphocytes dominate (74, 12% +/- 6.79) while the part of plasmacytes varied between 1.8% and 29.2%. In spite of the exclusion of bacterially infected and necrotic tumor sections an average percentage of granulocytes (10.25% +/- 5.30) was ascertained in the inflammatory cell infiltrate.

Carcinoma, Squamous Cell↗
PubMed1991

[Clinico-anatomic study for constructing pedicled myocutaneous trapezius flaps].

The authors investigated musculocutaneous flaps, paying particular attention to vascular anatomy, the development and length of their main vessels, their potential arc of transposition. Beyond that, their applications for soft tissue coverage in the head and neck region and procedures for coverage of the donor site were studied. When compared with the literature, the results show that pedicled musculocutaneous and osteomusculocutaneous trapezius flaps are especially suited for reconstructive surgery of the head and neck.

Aged↗
PubMed1990

Can chlorpromazine prevent flap necrosis?

The influence of chlorpromazine hydrochloride on failing, cranially-based dorsal flaps of female rats (Uje:WIST) was studied. The drug was injected subcutaneously into the abdomen pre- and postoperatively. The dosage was 1.5 mg/100 g preoperatively and 0.75 mg/100 g body weight every 12 hours following flap replantation for 10 consecutive days. No improvement in the survival rate was achieved by administration of chlorpromazine hydrochloride in this rat strain.

Animals↗
PubMed1990

Method of Converse for correction of prominent ears: comparison of results.

We compared the objective and subjective evaluations of the results after correction of the earposition by the method of Converse with the results by the method of Reichert and Mustarde. The mean values obtained by the method of Converse correspond to the mean normal values. The patients are very satisfied with their results. A comparison of the results of these three methods do not show any aggravating differences.

Adolescent↗