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Biomedical subjects

W Lierse

Publications and source records attributed to W Lierse.

At least 19 recordsLinked to original sources

[Angio-architecture of the colon in Crohn disease and ulcerative colitis. Light microscopy and scanning electron microscopy studies with reference to the morphology of the healthy large intestine].

The etiology and the pathogenesis of the chronic inflammatory bowel diseases known as Crohn's disease and ulcerative colitis have not been defined. Therefore, in this study the main emphasis was placed on description of the pathologic anatomy. Disturbed blood supply and vascular disorders have been discussed as etiopathogenetic factors. The results in the literature are frequently contradictory. For this reason, the vascular system of the colon in Crohn's disease and ulcerative colitis was systematically examined by means of various morphological methods in this study. Microvascular corrosion casting and translucent specimens were taken from operative specimens taken from 12 patients with Crohn's disease and 8 with ulcerative colitis. For comparison, tumor-free parts of 6 colon cancer specimens were examined. The evaluation was done by scanning electron- and/or stereoscopic microscopy. In the presence of chronic inflammatory bowel disease dilatation of the submucosal veins, caliber differences in the tunica muscularis and rarefaction of the penetrating blood vessels were found. In summary, an impairment of the blood flow in the tunica muscularis can be postulated. For the first time, the resulting venous stasis has been described, in contrast to the previously described disturbed arterial blood supply.

Adult

[New kinds of 3-dimensional atlases of the anatomy and function of the human body].

It is a drawback of classical multimedia programs for the visualization of spatial knowledge, that they are based on a limited number of predefined views. This paper describes a model that combines pictorial and symbolic knowledge about spatial structures in a way that allows arbitrary views of the scene and the interrogation of the model in the context of the actual view. The style of the pictorial presentation only depends on the objective and the phantasy of the user. The functionality of the approach is demonstrated with the example of the human head. It is furthermore shown that the model potentially allows the simulation or generation of all classical visual teaching aids for anatomy.

Anatomy, Artistic

Anal endosonography in healthy subjects and patients with idiopathic fecal incontinence.

PURPOSE: This study investigates the normal ultrasonographic morphology of pelvic floor striated muscle and evaluates whether there are differences between males and females and between healthy subjects and patients with idiopathic fecal incontinence. METHODS: Manometric and ultrasonographic studies of the anal canal were performed in 30 healthy volunteers and in 26 patients with idiopathic fecal incontinence. Verification of ultrasonographic findings was obtained by studying anatomic preparations. RESULTS: Ultrasonography reliably identified the internal and external anal sphincter and frequently visualized neighboring structures. In addition, it detected muscular structures that have not clearly been described previously. However, differences in external sphincter function between males and females and between healthy subjects and incontinent patients were not reflected by alterations in muscle thickness. CONCLUSIONS: Endosonography of the anal canal clearly delineates muscular structures and may even visualize structures that have been previously incompletely defined. However, it remains to be shown that differences in certain muscular functions have a morphologic correlate that can be detected by endosonography.

Adult

[Thermal side effects after use of the pulsed IR laser on meniscus and bone tissue].

Thermal effects on meniscus and bone tissue after application of 314 boreholes using five different infrared (IR) lasers: Nd:YAG, Tm:YAG, Ho:YAG, Er:YAG, Cr,Er:YSGG (application energy 200 mJ, 400 mJ, 600 mJ, 800 mJ, 1000 mJ; repetition rate 2 Hz, 5 Hz; medium air, water rinse) were analyzed. The experimental set-up comprised for the beam guiding a focussing lens (f = 100 mm) or a flexible fiber (Ho:YAG). Damaged tissue was investigated macroscopically, histologically, and by scanning electron microscopy. Application in air caused carbonisation in all cases. Application in water showed thermal brown discoloring using Tm:YAG, Ho:YAG laser on meniscus tissue. The Nd:YAG did not ablate. The Er:YAG laser showed macroscopically precise boreholes without any discoloring of the adjacent tissue as well in meniscus as in bone. Cr:ErYSGG laser results were comparable with the results using an Er:YAG laser although ablation on bone tissue created higher thermal effects. For the aim of developing minimal invasive operating techniques the Er:YAG laser showed best results.

Animals

A new method for practicing exploration, dissection, and simulation with a complete computerized three-dimensional model of the brain and skull.

In current practice, anatomical atlases are based on a collection of planar images presented in a book or, recently, stored on digital media. We present a new kind of interactive true three-dimensional (3D) anatomical atlases based on a volume model derived from MRI and CT. The model has a two-layer structure. The lower level is a volume model with a set of semantic attributes connected to each voxel. The semantic attributes are assigned by an anatomist using a volume editor. THe upper level represents a set of relations between these attributes. Interactive visualization tools such as multiple surface display, preparation of transparent material and cutting are provided. It is shown that the combination of this model with advanced tools for volume visualization provides the 'look and feel' of real dissection. The system therefore represents a bridge between real dissection of a cadaver and textbooks and classical atlases of anatomy. First tests have shown that the atlas system may be used successfully for teaching anatomy, but also as a reference for radiologists or surgeons. The powerful underlying data structure potentially includes all classical visual teaching aids. As a replacement of classical atlases, however, spatial resolution has still to be improved.

Anatomy

Visualization of neonatal anatomy and pathology with a new computerized three-dimensional model as a basis for teaching, diagnosis and therapy.

A new computerized three-dimensional (3D) volume model derived from a post-mortem MRI series of the chest and abdomen of a human newborn allows interactive dissection by removing, adding organs or cutting in unlimited directions. The advanced technique of real volume visualization instead of using contours allows one to study the normal and pathological anatomy of the neonate. Anatomical details of the pleural, pericardial and peritoneal cavities and of abdominal veins are demonstrated. Compared to conventional methods, the advantages of this model for teaching and as a basis for diagnostic imaging and therapeutic procedures are evident.

Abdomen

Ultrastructural studies on tumor capillaries of a rat rhabdomyosarcoma during fractionated radiotherapy.

Sequential morphological changes in tumor capillaries of istransplanted R1H rat rhabdomyosarcoma were observed weekly by transmission electron microscopy during fractionated radiotherapy (75 Gy/25 fractions/5 weeks). During the first 2 weeks of irradiation (up to 30 Gy), edema of the tumor capillary wall was induced. Swollen endothelial cells bulged into the vascular lumen and were surrounded by a widened subendothelial space with increase amounts of collagen fibrils (subendothelial edema). The endothelial lining was preserved up to the 3rd week of irradiation (45 Gy). Prolonged irradiation was associated with progressive destruction of the vascular wall including shrinkage, gradual loss of cell contacts, disappearance of the normal chromatin pattern, and increase of cytoplasmic vacuoles in endothelial cells as well as disruption of basal laminae. One week after the end of radiotherapy (75 Gy), the tumor capillaries showed complete necrosis. Progressive damage to tumor capillaries in the course of fractionated radiotherapy might have adverse effects on blood supply and thus on tumor oxygenation.

Animals

[Formation of a neofascia after implantation of a composite patch in the inguinal region].

In this study, a novel patch material composed of polyglactin 910 and polydioxanon was tested in animal experiments for its use in the surgical repair of hernias. The material was implanted laparoscopically into the inner inguinal region of three hybrid running-pigs. No postoperative complications were observed. The animals were killed 14 and 48 days after surgery. Both the macroscopic and microscopic examination showed a de novo formation of connective tissue at the site of implantation, which may be regarded as a new fascia. Due to the cooperation of fibroblasts and free cells of the connective tissue, new intercellular matrix was formed after the resorption of the implanted material. A model of this cell cooperation is outlined in the study. The technical advantages of the implantation material are demonstrated and its benefits for minimally invasive surgery emphasized. Because of its special properties, the material may be recommended for later clinical traits in the surgery of fascia.

Animals

[The arterial blood supply of the tibial and practical consequences].

In the periosteum of the human tibia, the arterial blood supply shows a general sectorial angioarchitecture. There are 4 segments: proximal and distal 1/5, proximal and distal diaphysis. The proximal 1/5 of the tibial periosteum is supplied with blood by the aa. recurrentes tibiales anterior et posterior and the aa. inferiores medialis et lateralis genus. At the proximal diaphysis (next 3/10 of the tibia) periosteal branches arise from the a. tibialis anterior and the a. tibialis posterior. The distal diaphysis (following 3/10 below the middle of the tibia) is nourished exclusively by semicircular rami periostales of the a. tibialis anterior, which move around the bone from both sides and join with each other at the facies medialis. It is the only sector, which is supplied by a single main artery. Concerning the periosteal blood supply of the distal 1/5 of the tibia 2 different types are found. In 2/3 of the cases the lateral side is nourished by a great vessel of the a. fibularis, which is supported by branches arising from the a. tibialis anterior. In 1/3 of the cases this vessel of the a. fibularis is absent and rami periostales of the a. tibialis anterior nourish the lateral aspect of the distal tibia alone. The dorsal region is 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 anastomoses. Both the facies lateralis and the facies posterior are supplied by direct branches, which arise from the main arteries of the lower leg.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Autologous rib perichondrial grafts in experimentally induced osteochondral lesions in the sheep-knee joint: morphological results.

The purpose of the present study was to examine the fate of autologous perichondrial grafts after transplantation into cartilage lesions in weight-bearing joints. Osteochondral lesions were made in the articular surface of knee joints in 36 sheep. The defects were filled with autologous rib perichondrial grafts which were secured by either collagen sponges (12 animals) or fibrin glue (12 animals). Defects without perichondrial grafts served as controls (12 animals). Following 1 week of immobilization of the operated leg, the plaster was removed and the animals were allowed to move freely. Animals were sacrificed after 4, 8, 12 and 16 weeks. The grafts were removed and investigated histologically. In contrast to weight-bearing areas and control defects, hyaline-like cartilage formation was seen in non-weight-bearing areas after 4 weeks. This newly formed cartilage revealed strong metachromasia following staining with acidic toluidine blue and reacted positively with periodic acid-Schiff, indicating de novo synthesis of proteoglycans and glycoproteins. Scanning electron microscopy and examinations with polarized light confirmed a hyaline cartilage-like architecture for the surface area as well as for the fibre orientation of the whole graft. Enzyme histochemistry for alkaline and acid phosphatase activity showed positive reactivity only at the base of the transplants.

Animals

[Design of a tibial intramedullary nail based on anatomic studies of intraosseous vessels].

The design of the tibial medullary nail can be improved in order to preserve intraosseus vessels by osteosynthesis of the tibia. The nutrient artery of the human tibia enters the compacta in an average height of 33% dorsally and is leaving it in a height of 50% of the tibial length. In the medullary cavity the vessel splits up. The main branch continues the distal course on the dorsal/dorsolateral side of the medullary cavity (endosteal). In the distal diaphysis this endosteal vessel is of great importance, since the periosteal blood supply in this region with high incidence of pseudarthrosis is guaranteed only by branches of the anterior tibial artery. Using a new unreamed tibial nail, which is flattened dorsally, it is possible to preserve the endostal main artery of the tibia.

Aged

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

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

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

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

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

[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

[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