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Biomedical subjects

W Lierse

Publications and source records attributed to W Lierse.

At least 37 records · Page 2Linked to original sources
PubMed1992

The physiology and pathology of the esophagus.

The esophagus and trachea derive from the foregut during the 4th week of development and is constructed as a part of the gut: longitudinal and circular muscle bundles are connected to a functional system together with collagen and elastic fibers. The action of the cricopharyngeal "pinch-cock" is pronounced in the newborn. In the region of the upper orifice ganglion cells are absent and venous vessels are oriented in a longitudinal direction. The myoelastic fiber system is in the lower part of the esophagus arranged as a stretching system, and the esophagus becomes longer and narrower by traction. The blood vessels derive from the thyroid arteries, the aorta, the bronchial arteries, the left gastric artery and the left inferior phrenic artery. Poor zones of vascularity are in the middle of the ventral and dorsal plane.

Embryonic and Fetal Development↗
PubMed1992

New tool combination: XeCl-excimer laser and tapered fiber enhances potential for atraumatic hard tissue operations.

XeCl excimer lasers have already been used to ablate bone, however, until now the results have been unsatisfactory until now. First, ablation of bone in air produced macroscopic noticeable carbonizations similar to those produced by thermal infrared lasers. Second, ablation rates were very low even on meniscus tissue. A new tool combination, XeCl excimer laser and tapered fibers, obtain higher ablation rates, because of its efficient light guiding capability. Using a liquid medium (water, normal saline solution) during laser application prevents macroscopic noticeable carbonizations.

Animals↗
PubMed1992

Macroscopic and microscopic findings after excimer laser treatment of different tissue.

In reported tests, the interaction of excimer laser radiation with bone, meniscus, and tendon tissue was observed. Depending on various laser parameters, different tissue reactions were observed in all procedures. Ablation was performed in a liquid medium to ensure extended carbonizations even at low application energy and repetition rate. Our studies revealed that the longer the pulse, the lower the destruction rate of fibers. However, a longer pulse caused lower ablation rates than a shorter one. An increase of repetition rate instead of an increase of application energy resulted in higher heat accumulation in the adjacent tissue. Differentiation of the single parameters on various tissue allows flexibility of thermal effects from the laser procedure.

Achilles Tendon↗
PubMed1992

Sectorial angioarchitecture of the human tibia.

The blood supply of the periosteum of the human tibia was investigated by anatomical dissection of 12 lower extremities which were filled with injection mass. By division of the tibia into 4 segments (proximal and distal fifths; proximal and distal diaphysis) a general supplying system of the periosteum was found. The proximal fifth of the tibial periosteum is nourished by branches of the arteriae recurrentes tibiales anterior et posterior and the aa. inferiores medialis et lateralis genus. At the proximal diaphysis (next three tenths of the tibia) periosteal branches arise from the aa. tibialis anterior and posterior, whereas the distal diaphysis is nourished exclusively by semicircular vessels of the a. tibialis anterior which twine around the bone and merge with each other at the facies medialis. Concerning the periosteal blood supply of the distal fifth of the tibia, two different types were found. In two thirds of the cases the lateral side was nourished by branches of the a. tibialis anterior, which are supported by vessels from the a. fibularis. In one third the latter branch was absent so that the rami periostales arising from the a. tibialis anterior nourished the lateral aspect of the distal tibia alone. The dorsal region was supplied in all cases by rami of the a. fibularis and a. tibialis posterior. On the medial side the periosteal nourishment is ensured only by anastomosis. Branches of the a. tibialis anterior supply the facies lateralis and facies posterior where it is supported by vessels of the a. tibialis posterior and in a minor region of rami of the a. fibularis (distal) and a. poplitea (proximal).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Functional construction of the sacroiliac ligamentous apparatus.

The sacroiliac ligamentous apparatus was examined as a part of a biomechanical pelvis-lower extremities system. The ligamentous apparatus of two pelves was freed, and the findings concerning the ligaments and their direction were drawn by a modular constructed, three-dimensional calculator model of the pelvic region. The ligamentous apparatus of the sacroiliac joint belongs to a functional system. Its task is to minimize every movement in this amphiarthrosis. The ligamentous apparatus shows an adaptation to strong or long-time-acting stresses. The junction between the os sacrum, pelvis and the ligamentous apparatus of the sacroiliac joint can be described as self-tightening. Local stresses are also reduced by the ligaments. A loosening in this system, which has to fix the os sacrum to the pelvic girdle, leads to a static insufficiency. The consequence is pain due to an irritation of the lumbosacral trunk. The exact description of the structure allows a representation according to the laws of similarity mechanics. With such a representation one can build up a computer-aided biomechanical model of the pelvis-lower extremities region. Examples for such a model are biomechanical finite-element models. By observing the laws of similarity mechanics (an exact description of geometric, physical and functional conditions) an efficient biomechanical model can be constructed that also takes into consideration the complex functional circumstances, in contrast to previous models. In order to construct such a model, one has to feed the findings of the examination into a data bank, which has to be demanded.

Biomechanical Phenomena↗
PubMed1992

Developmental changes in the distribution of cecal lectin-binding sites of Balb-c mice.

The existence of lectin-binding sites was investigated in the cecum of Balb-c mice at seven developmental stages ranging from 18 days post conception (p.c.) to 8 weeks after birth. Nine horseradish-peroxidase-conjugated lectins (concanavalin A, Triticum vulgaris, Dolichus biflorus, Helix pomatia, Arachis hypogaea, Glycine maximus, Lotus tetragonolobus, Ulex europaeus, Limulus polyphemus) were applied to 5- to 7-microns thin paraffin sections of Bouin-fixed tissue. After DAB staining the sections were evaluated by light microscopy. It was shown that each lectin exhibits a unique developmental pattern. The adult binding patterns were established at the age of 3-4 weeks with only minor changes occurring thereafter. Considerable differences in binding patterns occurred not only between lectins of different groups but also between lectins with the same nominal monosaccharide specificity.

Age Factors↗
PubMed1992

Anatomy and function of the bursa subacromialis.

The ligamentum coracohumerale, as the anterior limit of the bursa subacromialis, runs into the shoulder joint capsule, connecting--broadly based--above the sulcus intertubercularis. It does not, however, originate--as described previously--from the base of the processus coracoideus (viewed frontally), but rather medially from the base, i.e. on the side of the fossa supraspinatus. The sliding mechanism starting at 50 degrees affects the parietal sheet of the bursa subacromialis, whereby the laterally situated section slides under the medially situated section. With an abduction of up to 50 degrees, the lateral section congests in front of the corner of the acromion, sliding from there under the acromion, so that the--hitherto--medial section is located above the section now sliding away beneath it. This sliding mechanism continues on up to 100 degrees. At this point the parietal sheet of the bursa subacromialis lies as follows: The section that had been situated laterally at the beginning of the sliding mechanism now lies caudally to the section that had lain medially at the outset. The bursa subacromialis does not slide fully into the fossa supraspinatus, as in all of the cases observed, it is firmly connected, together with the fascia subdeltoidea, to the corner of the acromion. The visceral sheet does not change in the course of the sliding mechanism as described, as it is connected to the fascia of the supraspinatus muscle--with the exception of a medial stretch of 16 mm. A further finding deals with the course of the muscles of the caput breve of the biceps brachii. Individual muscle fibre components do not connect to the processus coracoideus, but rather run before the tip of the processus coracoideus into the ligamentum coracoacromiale, radiating not only into the ligamentum coracoacromiale, but also--certain components--into the shoulder joint capsule. Through this, the 'aponeurosis tendinis brachii' forms a tendon roof in front of the processus coracoideus that extends to the structures running along the head of the humerus. The muscle fibre components of the caput breve of the m. biceps brachii radiating into the shoulder joint capsule, together with the muscles of the rotator cuff and the ligamentum coracohumerale, keep the shoulder joint capsule tense, thus preventing constriction symptoms.

Bursa, Synovial↗
PubMed1992

Anatomical study of the blood supply in the human shoulder region.

The blood supply of the shoulder muscles, ligaments and joint capsule was investigated by injection of silicone rubber into the arteria subclavia of postmortem cases. We show that the a. suprascapularis forms important anatomoses with other arteries in the region and is of greater importance for the blood supply of the rotator cuff as hitherto believed. We also describe the a. subcoracoidea as a so far unknown branch of the a. axillaris.

Axillary Artery↗
PubMed1992

[Vessels of the brachial plexus].

The blood supply of brachial plexus is described by means of lightened injected specimens of older human fetus. The following arteries have direct branches to brachial plexus: the aortic arch/brachiocephalica trunk, subclavia a., thyrocervical trunk, ascending cervical a., transverse cervical a., suprascapular a., and the acromial network. Secondary branches leave them that partly anastomose and also return from distal to proximal. The blood supply is luxurious.

Brachial Plexus↗
PubMed1991

Intraperitoneal hepatocyte transplantation: morphological results.

The value of isolated intraperitoneal hepatocyte transplantation as a temporary support in acute hepatic failure is controversial since the functional capacities and survival rate of auxiliary transplanted liver cells are uncertain. It was the aim of this study to investigate the survival rate of intraperitoneally (i.p.) transplanted hepatocytes and microcarrier attached hepatocytes. In 25 rats (group A) an i.p. hepatocyte transplantation and in 30 rats (group B) an i.p. microcarrier attached hepatocyte transplantation was performed and the animals were killed at 3 h, 12 h, 24 h, 3 and 7 days (group A) and 1, 2, 3, 7, 14 and 28 days (group B) after transplantation. Histological investigation showed that transplanted hepatocytes undergo complete cell necrosis within 3 days (groups A and B). Liver cell necrosis was followed by a peritoneal reaction resulting in granuloma formation in both groups. Since liver cell necrosis occurred soon after transplantation and could not be avoided by attachment of liver cells to microcarriers, it can be concluded that metabolic support from transplantation cannot be expected in acute hepatic failure.

Animals↗
PubMed1991

Morphometric evaluation of chondrocyte cavities in normal and prearthrotic human femoral heads.

In 25 human femoral heads, the structural changes in the chondrocyte cavities of prearthrotic cartilage were determined in three different layers by detailed morphometric evaluation. As examination parameters, the area, perimeter, diameter, and the form deviation from a circle (form PE) were chosen. In addition, we calculated the numeric cell density and the mean distance between two chondrocyte cavities. For intraindividual comparison, the same data were obtained from nondegeneratively changed cartilage areas of each femoral head. The main arthrotic regions were located in the weight-bearing area of the femoral head, particularly in the dorso- and ventrolateral quadrants. The number of chondrocyte cavities as well as the numeric cell density were decreasing from superficial to basal layers, whereas the mean distance between two chondrocyte cavities was increasing. Concerning these parameters, no significant differences were seen between the prearthrotic and control groups. We found that the chondrocyte cavities in the superficial layer in prearthrotic areas show a tendency to smaller volumes in comparison with nondegeneratively changed areas, whereas in the basal layer, no difference could be seen. We presume that the changes in the articular cartilage are not related to an insufficient supply of the cartilage with nutriments, but probably to the high mechanical strain applied to its surface.

Aged↗
PubMed1991

[Angioarchitecture of the cricoid cartilage and anterior trachea].

Two dense capillary networks have been described lying in the anterior and posterior parts of the human cricoid cartilage. Between these two lies an area supplied by a very sparse capillary network. The anterior sector is derived from branches of the cricothyroid and inferior laryngeal arteries, the posterior from branches of the superior and inferior laryngeal arteries. The tracheal cartilages are supplied from above downwards by circular branches derived from two parallel longitudinal arteries. Therefore the centre of each cartilage is very sparsely supplied by small arteries.

Aged↗
PubMed1991

[The fascia of the inguinal canal ring].

The fascial anatomy of the inguinal canal has been investigated. The spermatic cord is fixed by two cords in addition to its embedding in connective tissue after leaving the inguinal canal. The spermatic cord has a special fastening in form of a noose at the deep inguinal ring. The transversalis fascia consists of an internal and an external leaf. A part of the internal leaf forms with three cords this noose and builds so a sphincter-like closure mechanism, which reduces the size of the deep inguinal ring by a local erection of the transversalis fascia. The internal leaf protects from an indirect inguinal hernia as well as from a direct inguinal hernia, because the wall of the so-called Hesselbach's triangle only consists of the internal leaf. A list of the anatomical synonyms is added.

Abdominal Muscles↗
PubMed1991

[CCL-tensulae in the skeleton as part of a hydrodynamic skeletal system].

Previous morphological studies on human bone have demonstrated that veil-like structures ('tensulae') occur in highly stressed regions, i.e. the interface between cartilage and bone. In the present report we describe the distribution of tensulae within various types of human bone by means of scanning electron microscopy and light microscopy. Tensulae were predominately located within bone tissue adjacent to mineralized cartilage. The surface diameter of tensulae ranged from minimal 50 to maximal 400 microns. Occasionally, collagen fibers extended from the interface between cartilage and bone to tensulae. Frequently, the latter were attached to fat cells as well as bone marrow cells. An elemental analysis of tensula revealed high levels of calcium and phosphorus of equal concentrations. However, bone tissue contained higher levels of calcium compared to phosphorus. Additionally, a monoclonal antibody was generated by immunizing rats with bone marrow of mice. Within bone tissue this monoclonal antibody selectively stained membrane-like structures which were clearly identified as tensulae. From our investigations we conclude that the function of tensulae in bone may be to absorb stress in regions where large forces are applied.

Animals↗
PubMed1990

[The course of fibers in the central tendon].

In each polytrauma a diaphragmatic rupture is possible. Usually the rupture is located in the central tendon. A cause of the bizarre form of ruptures is the individual arrangement of gaps between the fibres of the central tendon. These fibres are classified in three groups. A rupture is generally on the left side of the central tendon. A further cause of the relative rare rupture on the right side is beside protection by the liver the greater stability on the right side of the central tendon, because fibres are more interlocked. The diaphragmatic rupture of a polytrauma is often overlooked, this number could be reduced by specific diagnostics. The repair of a diaphragmatic rupture is not a problem, an abdominal approach should be preferred. The prognosis depends on extension of concomitant lesions.

Aged↗
PubMed1990

[Detection of hydrodynamically operative tissue in the substantia spongiosa of the femoral head in Bos taurus and Ovis aries].

The authors show the presence of CC-Tensulae in Bos taurus and Ovis aries. They define CC-Tensulae as tense membranes in openings between the trabeculae of spongy bone. These structures were interpreted in man as a hydrodynamic subsystem which serves the flow and the impulses of mechanical forces. The authors point especially to the similarity that exists between their findings and what has been seen in man.

Animals↗
PubMed1990

Functional construction of the superficial and deep fascia system of the lower limb in man.

The muscular system, the connective tissue and the bones are the components of a biomechanical pelvis-lower extremity model. The occasional electrical events in the muscles were not taken into account, as they can only be measured by physiological methods. In this publication, the connective tissue of the lower extremities is examined. The connective tissue system of the thigh and leg was prepared; after removal of the muscles the so-called 'hollow' lower extremity could be studied. A topographical documentation followed, and the structure and directions of the fibers were observed with polarized light. The connective tissue systems of the lower extremities and bones form a biomechanical, effective and functional system, the bone-fascia-tendon system. The components of the connective tissue in such a system are the fascia lata, the crural fascia, the iliotibial tract, the femoral and crural intermuscular septa, and the membrana interossea. The iliotibial tract is not the sole part of this system having a tension band effect, other components--above all the lateral femoral intermuscular septum--also reduce the forces acting on the bones. Therefore, the tensile strength of the iliotibial tract has to be considered lower as supposed. The iliotibial tract is not a part of the fascia lata; it is an independent, vertically tightened tendon of the 'pelvic deltoid muscle' (gluteus maximus, tensor fasciae latae). The iliotibial tract passes over the greater trochanter like on a roller bearing. It is not attached directly to the greater trochanter and to the lateral femoral condyle, so that previous models have to be modified. The iliotibial tract glides in a fascia bag which is composed of oblique and horizontal fibers of the broad fascia. The iliotibial tract, as tendon of the pelvic deltoid muscle, continues in a lateral location into the leg where it is fixed to the lateral malleolus. The present report provides a new description of the structure of the connective tissue system of the lower extremities. The model reported complies with the laws of similarity mechanics by describing exactly the geometric, physical and functional conditions. This representation could facilitate the construction of a computer-aided, efficient, biomechanical model of the pelvis-lower extremity region considering also the complex functional circumstances, in contrast to previous models. In order to construct such a model, the data obtained by the examination of the connective tissue of the lower extremities have to be given into a data bank, which, however, has to be built up.

Biomechanical Phenomena↗