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Biomedical subjects

H Scheller

Publications and source records attributed to H Scheller.

At least 19 recordsLinked to original sources
PubMed1999

[Masticatory rehabilitation of tumor patients by endosseous implants. 10 year analysis].

A total of 409 implants was inserted into 83 consecutive patients, who had tumor-related intraoral resections of soft tissue and bone. A life table analysis was used to determine the survival rate of the implants placed over a period of 13 years. Log rank tests and a Cox regression analysis were employed to identify relevant effects of surgical parameters on implant survival. A total of 38 implant failures were encountered. Most of the losses (n = 16) occurred during the first year of functional loading. The cumulative, overall survival rate of implants was 56.5%. Previous radiation therapy, insertion into grafted bone or original jaw bone, and insertion into microsurgically revascularized grafts did not significantly affect the survival rates. In the Cox regression, only the timing of implant placement was significantly related to the survival rate in the group of patients with bone grafts (P = 0.0197), with a lower survival rate of 36.2% of primary inserted implants and 67.1% survival in the group with secondary implant placement.

Bone Transplantation↗
PubMed1997

Expression of CD66a (human C-CAM) and other members of the carcinoembryonic antigen gene family of adhesion molecules in human colorectal adenomas.

Among the members of the carcinoembryonic antigen (CEA) family, CD66a (human C-CAM) and CGM2 (CEA gene family member 2) mRNAs are frequently down-regulated in colorectal cancer. In contrast, nonspecific cross-reactive antigen (NCA) mRNA is overexpressed in the majority of these carcinomas. In animal models, the rodent homologues of CD66a have been shown to act as tumor suppressors, suggesting an important role in carcinogenesis. Here we investigate the mRNAs of CD66a, CGM2, and NCA in 22 human colorectal adenomas and the respective normal mucosa specimens by Northern blots. The expression of both CD66a and CGM2 changed in a concomitant fashion. Using oligonucleotides specific for the N-terminal domains, two CD66a transcripts 3.9 and 1.5 kb in size were identified. These showed a greater than 50% down-regulation in 20 of 22 and 18 of 22 adenomas, respectively. Reduction of the CGM2 message was observed in 21 of 22 cases. Complete or near-complete losses of the CD66a 3.9-kb mRNA and the CGM2 message were found in 13 of 22 and 15 of 22 of the tumors, respectively. The medians of CD66a and CGM2 expressions were between 0.3 and 0.0, respectively. The tumor:normal ratio of NCA mRNA expression was increased up to 2.4-fold in 11 of 22 adenomas. Altogether, these results compare well to the changes reported previously for colorectal carcinomas. The high frequency and early appearance of dysregulation of members of the carcinoembryonic antigen family during colorectal tumorigenesis suggests that these changes may be important for the development of the malignant phenotype.

Adenoma↗
PubMed1994

[Functional and esthetic reconstruction of complex facial defects after tumor resection and trauma].

Nowadays, free revascularized myocutaneous and osteomyocutaneous flaps are available as grafts of high biological value, which allow functional and esthetic rehabilitation after tumor resection and trauma. The use of these flaps however must be considered carefully, since these techniques require a good general physical condition of the patient for extensive surgery and a considerable operation time. Therefore we consider these flaps as adequate solely in cases of poor recipient site conditions after previous irradiation or chronic infection, in cases of extensive scar formation and in large bone and soft tissue defects. In these cases revascularized grafts from the iliac crest have proven to be useful in mandibular reconstruction while scapular grafts has been useful in restorations of the midface.

Bone Transplantation↗
PubMed1991

[Studies on the effects of abutment position on the prognosis of endosseous implants].

Although the use of osseointegrated Brånemark implants is associated with a high success rate, late losses of primarily osseointegrated implants have been observed again and again. In this study 50 patients were evaluated to clarify the effects of abutment position on late losses. The results have shown that implant position is less important for the loss of implants than other parameters such as healing disorders or poor oral hygiene.

Dental Abutments↗
PubMed1990

Combination of microsurgical tissue reconstruction with osteointegrated dental implants. Presentation of a technique.

A technique is presented in which resected mandibles are restored with a combination of microsurgically revascularized jejunal grafts and bone grafts. The bone grafts served as a recipient for Branemark implants. The preliminary results showed that the jejunal mucosa tolerates the implants well and the masticatory function was adequately restored in the patients discussed.

Adolescent↗
PubMed1990

[Dermatologic effects of two facial prosthesis materials in combination with glues].

Erythema is frequently observed in the region of contact between facial prostheses and the skin. In a large-scale study on the cutaneous tolerance of facial prosthesis materials, two prosthetic materials (glue and the solvent for the glue) were tested in the allergy test after Magnusson and Kligman (OECD). Only the solvent showed a moderately pronounced allergenic potential in the macroscopic assessment.

Adhesives↗
PubMed1989

[Possiblities and limitations of implantology in older patients].

Inspite of major progress in preventive dentistry the loss of all teeth is still considered characteristic of old age. In addition to the classical procedures of preprothetic surgery for an improvement of the denture bearing structures the insertion of implants into an edentulous ridge has gained increasing importance in recent years. In view of the great clinical practicability and success rate of osseointegrated implant systems we decided to insert implants into an edentulous ridge also in patient with generally compromised health and severely atrophic jaws to restore of masticatory function in these cases. Complete restoration of masticatory function so far has been achieved in 35 patients over the age of 65 by insertion of osseointegrated implants alone or in combination with a bone graft. Results may be summarized by saying that age is not of particular relevance for patient selection before osseointegrated implants are inserted. It is more important to carefully assess morphological structures, physical and psychological status, and individual stress tolerance of the patient.

Aged↗
PubMed1989

[Studies on the closeness of the marginal fit of Ceraplatin crowns].

The clinical success of crowns is determined by their accurate marginal fit. The marginal defects of 20 finished Ceraplatin crowns, manufactured by 10 different laboratories, were recorded after cementing on working casts and the original preparations. The findings demonstrated that the margins of Ceraplatin crowns were insufficient under clinical conditions.

Crowns↗
PubMed1976

[Diurnal rhythm of lysosomal organelle decomposition in liver, kidney and pancreas].

The amount of autophagic vacuoles which, under certain presumptions, can be used as a measure of the intensity of cellular autophagy shows clear cut diurnal changes in untreated rats. Liver parenchymal cells, epithelial cells of proximal convoluted tubules of the kidney, and acinar cells of the exocrine pancreas were investigated. The rhythm is synchronous for these three cell types. The "maximum" was found during the light period, the "minimum" during the dark period. The quantitative findings are in keeping with the assumption that cellular organelles are destroyed exclusively by cellular autophagy. Different turnover rates of mitochondrial and peroxisomal constituents, as determined in biochemical experiments, are paralleled by different relative frequencies to which mitochondria and peroxisomes occur in autophagic vacuoles. In liver cells the physiological rhythm can be influenced by alteration of feeding conditions. It is inverted when a single daily meal is fed in the first half of the light period. In early starvation the level of the diurnal "maximum" of cellular autophagy continues for the first hours of the dark period until a slow decline takes place. Cellular autophagy is completely stopped for several days when rats are refed after starvation for 5 days.

Animals↗
PubMed1975

A morphometric study of cellular autophagy including diurnal variations in kidney tubules of normal rats.

Cellular autophagy in convoluted tubules of kidney was studied in 24 rats, killed in pairs at constant time intervals during one diurnal cycle, by (a) morphometric evaluation of tubular cells by the point-counting method in randomly sampled micrographs, and (b) selective search for autophagic vacuoles (AV) directly on the electron microscopy screen. The total area of tubular cells recorded in the electron microscopy sections was 93 X 10(-4) mum2. Since the distal convoluted tubules, covering about 12% of the whole tubulocellular area, contained only 3-4% of all AV, they were omitted from the main calculations. The number of AV per area unit and the total amount of segregated material showed a distinct diurnal rhythm, synchronous for the different types of AV which were distinguished from each other according to their contents. The minimum was found during the night, the maximum during the day. This rhythm appears similar to that described elsewhere in liver cells. The mean segregated fractions were calculated from the relation of segregated to nonsegregated material in proximal convoluted tubular cells. The segregated fraction of the mitochondria was 4.4 X 10(-4). This value could account for the degradation of all mitochondria in a cell within 15 days, i.e., the upper limit of the lifetime of mitochondrial DNA in the cortex of the kidney, if one assumes that a mitochondrion is destroyed within 10 min after being segregated. The degregated fraction of microbodies was 11.7 X 10(-4). This suggests a shorter lifetime of these organelles. It is concluded that cellular autophagy plays a significant role in the turnover of cytoplasmic constituents, including the membranes of the endoplasmic reticulum.

Animals↗