Search PubMed⌕ Search

Biomedical subjects

R Ewers

Publications and source records attributed to R Ewers.

At least 19 recordsLinked to original sources
PubMed1991

[Articular disk dislocation in the human TMJ].

A three-dimensional model of articular disk dislocations has been developed. Histological examination of 35 temporomandibular joints in near sagittal section reveals sometimes extreme anterior displacement in about 50% and slight posterior displacement of the disk in 6% of the specimens. In the frontal plane medial dislocation prevails in more than 70% of the 32 specimens evaluated, whereas there is only one lateral dislocation. Within the predominantly medio-anterior direction of dislocation there are, however, variations. Excentric forces relative to the center of gravity of the disk always result in dislocations accompanied by rotation in the anterior or posterior part. Where the resulting forces apply on the center of gravity there is a translation in a medio-anterior direction.

Aged↗
PubMed1990

Lactate dehydrogenase isoenzymes in squamous cell carcinomas of the oral cavity.

Lactate dehydrogenase (LDH; EC 1.1.1.27) isoenzymes in human epithelial cells from squamous cell carcinomas and healthy tissues of the oral cavity of five patients were analyzed using isoelectric focussing. A new basic isoenzyme and high LDH-7 and LDH-9 activity were found in tumor cells in contrast to epithelial cells of adjoining nontumor tissue. These findings indicate that gradual changes in the percentage distribution of LDH isoenzymes may represent a useful parameter of disease activity in patients with squamous cell carcinomas.

Adult↗
PubMed1989

Inhibited methionine incorporation in human squamous carcinomas of the oral cavity as a measure for response to 5-fluorouracil.

Human epithelial cells and fibroblasts from malignant tumors and healthy tissues of the oral cavity were exposed in vitro to increasing concentrations of 5-fluorouracil. In order to determine whether the two cell types showed a difference in uptake, accumulation was measured over time using tritiated fluorouracil. Maximal drug uptake occurred in highly proliferative epithelial cells from cancerous tissue at 3 h, whereas fibroblasts from the same tissue and other cell types from healthy tissue exhibited a steadily increasing uptake over a long period of time. By use of [3H]methionine, a direct correlation could be demonstrated between the amount of incorporated drug and the fall in the rate of de novo protein synthesis. Furthermore, suppression of protein synthesis was closely related to the inhibition of cell division. These results indicate that the level of de novo protein synthesis can be a direct measure of the anticancer effect of fluorouracil.

Carcinoma, Squamous Cell↗
PubMed1989

[Spheno-occipital synchondrosis--a fluorescence and polarization microscopy study in Cercopithecus aethiops monkeys].

On 17 Cercopithecus aethiops monkeys we investigated with the method of the polychromic sequential dye marking system the histomorphology as well as the dynamics of growth and calcification of the spheno-occipital synchondrosis. The age of the animals ranged from change to teeth to late adolescence. The animals had been divided into four different groups: I: late change of teeth; II: young adult; III: fully grown; IV: late adolescence. In the first group the spheno-occipital synchondrosis showed no ossification in the gap which is filled with cartilage. It showed the characteristic structure with a central zone of equally distributed chondrocytes. Adjacent to this we found a zone of proliferation cell hypotrophy and cell degeneration. With increasing age there is decrease of the density of cells (groups II to IV) and after change to teeth the synchondrosis starts to ossify (group II). Due to the ossification the synchondrosis subdivides into different cartilage regions. We found that the closing of the synchondrosis started in the cranial region and progressed toward the caudal region. During this procedure the synchondrosis never ossified completely. Several cartilage regions persisted uncalcified until late adolescence. Interstitial growth of the synchondrosis was found until the end of the change of the teeth (group I). This growth which was always found in a sagittal direction ceased after bony connections had been formed between both poles of the synchondrosis. The sphenoidal and occipital pole of the synchondrosis showed equal growth potential.

Aging↗
PubMed1989

Rehydration of lyophilised cartilage grafts sterilized by different methods.

In in vitro experiments weight increase and rehydration speed of lyophilised cartilage grafts sterilized by different methods were determined. For periods of up to 72 h the increase in weight during rehydration was measured. The methods of sterilization used is only of little significance for such weight increase. Differences in rehydration speed clearly correlate with the initial weight of the lyophilised cartilage grafts. Smaller grafts are completely rehydrated after 5 to 6 h. This may explain the discrepancies in rehydration speed reported in the literature.

Absorption↗
PubMed1989

[Perioperative treatment of patients with chronic TMJ diseases].

The concept of perioperative diagnosis and treatment of patients with chronic TMJ disease has been confirmed by a follow-up examination of ten female patients after surgical treatment. Eight of the ten patients were pain-free after observation periods of 3 to 20 months. Following an initial bite-guard splint therapy, instrumental functional analysis, MR tomography and arthrographic visualization of dynamic movement profiles are indispensable. The results have also shown that, depending on the intraoperative finding, a postoperative splint therapy should be performed for six months.

Adult↗
PubMed1989

[Compression joint as a differential diagnosis in chronic facial pain].

"Costen's syndrome" is generally used to label chronic pain in the periauricular region. This article presents the results of a post-treatment evaluation of 50 patients, 25 of whom were referred to hospital with Costen's syndrome indicated in the diagnosis. As a result of this study it is proposed that the term "compression joint" be used instead of "Costen's syndrome". The importance of proper diagnostic procedures is pointed out.

Chronic Disease↗
PubMed1989

Mathematical outline-analysis of eminence and fossa of the TMJ of Cercopithecus aethiops (Cercopithecidae, primates, Mammalia).

The contours of the eminence and the fossa of the temporomandibular joint (TMJ) of Cercopithecus aethiops, a monkey species, are analyzed in sagittal-vertical sections. The functionally relevant contours can be approximated by catenates for both the eminence as the protrusive guidance and the fossa as the retrusive guidance. This study reveals the more general character of the contour formula y = a cosh(x/a) - a. This may be true because all these catenates are similar to one another and since they can be found in the guiding contours of the components of the stomatognatic system in man as well as in Cercopithecus aethiops.

Animals↗
PubMed1988

Reconstruction of the mandibular denture bearing area and freeing of the tongue after tumor surgery.

Vestibuloplasty together with a loosening of the tongue and covering the mucosal defects either with a split thickness skin graft or an autologous mucosal graft was performed on 35 patients previously treated for squamous cell carcinoma. The interval between tumor resection and the reconstructive procedures averaged 20 months. In 34 patients the denture bearing area improved, and in 31 patients, better mobility of the tongue occurred with, therefore, better phonation.

Adult↗
PubMed1988

Algae-derived (phycogene) hydroxylapatite. A comparative histological study [corrected and issued with original paging in Int J Oral Maxillofac Surg 1988 Oct;17(5)].

3 granular hydroxylapatite (HA) biomaterials, solid, coralline and phycogene HA (obtained from calcifying algae), differing widely in their relative amounts of specific surfaces and their origin, were examined with regard to their effects on bone healing in rats. Trephine drill holes were produced in the rat femur and filled with the HA granules. Each biomaterial produced a characteristic pattern of bone healing. Bioceramics with a small surface area showed random bone-implant contacts. Biomaterials offering large surface areas showed a dense bone-implant interface. Evidence is presented to suggest that a large specific surface favours osteoneogenesis and cell spreading on and into an implant.

Animals↗
PubMed1988

Reconstruction of the maxilla with a double musculoperiosteal flap in connection with a composite calvarial bone graft.

A new technique is shown for a one-stage reconstruction of the mucosa of the floors of the nose and maxillary sinus, the bone structures of the maxilla and the hard palate, as well as the mucosal layers of the hard and soft palates and vestibulum. To accomplish this coverage, a vascularized calvarial bone graft with temporal muscle from one side is combined with a vascularized temporal muscle flap from the other side to achieve a three-layer "sandwich" plasty. The advantage of this procedure is reconstruction of the complete maxillary defect with the possibility of denture rehabilitation and the avoidance of oronasal fenestration. Besides the possible complication of insufficient vascularization of the bone and muscle grafts, the donor defect in the calvarial bone and the missing muscle for mastication are to be considered.

Aged↗