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While several recent studies have focussed on the critical assessment of yield, purity and function of isolated islets, fine-structural investigations of isolated islets have been the subject of only a few studies. After intraductal injection of collagenase solution, the distended bovine pancreata were processed in a continuous digestion-filtration device, after which the purification of the islet suspension was accomplished by density gradient centrifugation. Purified islets were then prepared for light- and transmission electron-microscopic analysis. In semithin sections, no evidence of either connective tissue or exocrine tissue surrounding isolated islets was found. Endocrine cells exhibiting cytoplasmic granules were packed in clusters varying in size. In ultrathin sections, A-cells containing numerous secretory granules were distinctive; their cytoplasm contained conspicuous formations of rough endoplasmatic reticulum and juxtanuclear Golgi complexes. In the B-cells, the Golgi complexes were also prominent; these elements, however, were poor in endoplasmic reticulum and displayed characteristic B-cell granules surrounded by a halo. A few ultrastructurally heterogeneous cells were scattered among the identified cellular elements.

On the basis of an analysis of such methods that have led to the establishment of the Newtonian laws some problems of the interdisciplinary agreement between mechanics and biology, especially those concerning hard tissues, were discussed. In the light of examples it is shown that comparisons with technical constructions to explain form and function of bones are not sufficient since similarity of form is no proof of identical function. Mechanical phenomena of living matter can be investigated merely by their own movements whereby the differing qualities and reactions of the material have to be taken into priority consideration.

Movements of the mandible are recorded in vivo by a measuring system (MT 1602) that takes all 6 degrees of freedom of a rigid body into account. Class-I-patients were asked to move their mandible in the sagittal-vertical plane. The evaluation of the measurements yields an almost plane mandibular movement that only uses 2 degrees of freedom although a general plane movement normally possesses 3 degrees and although the human temporomandibular joint (TMJ) has a certain space of motion. This quantitative reduction of the degrees of freedom by one is produced by a neuro-muscularly guided dimeric link chain that cannot directly be related to anatomical landmarks. The diverse types of mandibular motion of a sound patient differ in the constant ratio of the angular velocities around the 2 axes of the dimeric link chain. Therefore, the paths of the individual mandibular points are epicycloids or hypocycloids. Patients with disorders of the TMJ and the neuromuscular feedback system do no longer show this constancy of the angular velocities' ratio. Besides that, we theoretically derive and empirically prove the fact that common axiographs do not record the "path of the hinge axis" of the TMJ, on principle. In this context we discuss some--in dentistry and anatomy widespread--fundamental misconceptions of the rigid body's kinematics.

On the basis of the ultrastructure of the Haversian lamellar system of bones analyses from the biomechanical viewpoint were undertaken. Instead of computed results preference was given to comparisons with tubes, fibres and nets so as to demonstrate clearly the building principle and movement phenomena. From the course of the collagenous fibres the tensile strains could be discerned which facilitated to determine also the direction of the compressive strains. The mineral components of the bone tissue are oriented toward the direction of the compressive strains. The construction principle of the lamella, however, facilitates reversible deformations and thus regeneration processes which distinguishes it from other technical building principles.

Peculiarities of renal corpuscle's structural organization of a number of animals representing various classes of vertebrates have been studied on submicroscopic level at the stages of excretory organs formation: pronephros, mesonephros and metanephros. The fact has been established that side by side with the common structure there have been specific peculiarities due to the level of evolutional development and character of habitat.

The ultrastructure of fetal and adult bovine epithelial-mesenchymal interface of the ruminal mucosa was described and then correlated to the biochemical analysis for glycosaminoglycans (GAGs). During development a progressive undulation of the basement membrane, increase of connective tissue filamentous material, and folding of the cellular membrane of the basal epithelial cells were observed. Coincidently, a decrease in the relative composition of hyaluronic acid and an increase in chondroitin sulfate was observed. These results suggest a correlation between glycosaminoglycans composition and the expression of some cellular events resulting in morphological changes which operate during ruminal morphogenesis.

Histomorphological and histomorphometrical observations were used to describe the development of masticatory muscles from normal and muscular dystrophic mice. The masseter and the digastric muscle were described from the birth to 35-40 week of age. It has not been possible by histomorphological criteria to separate dystrophic muscles from normal muscles at birth. From 2 weeks onwards marked differences between the affected and unaffected muscles appeared, as the affected fibres from this age are rounded with marked variations in size. Central nucleation is frequent and there is an increased amount of connective tissue between the fibres. The histomorphometrical observations revealed an increase in mean size of the fibres with age, both in normal and dystrophic masticatory muscles. The fibre size variance which has been shown to be a reliable parameter for description of degree of affection of dystrophic muscles, increased with increasing age in both groups. However, the variance is at all ages greater in the dystrophic muscles than in the normal ones, and is always greater in the masseter muscle than in the digastric muscle. There seems to be some small differences between male and female masticatory muscles, whereas no differences could be revealed between muscles from normal and heterozygous animals. Possible explanations of the obvious differences in degree and progression of the disease between the masseter and digastric muscle are proposed.

The theory--presented in part I--shall be examined by the synarthrosis (Gomphosis; Articulatio dentoalaveolaris) "Periodontium" and not by the intervertebral disk because the required experimental equipment can probably also be used in vivo. Of course, the results can be applied to the intervertebral disk since this theoretically represents the less difficult problem.