Magnesium content of human myometrium and placenta during various stages of gestation, and of different body fluids at term

Pregnancy is marked by a state of hypomagnesaemia but not much is known about the effects of maternal magnesium deprivation on the fetus. The aim of this study was therefore to measure magnesium concentrations in human myometrial and placental tissues and in different body fluids during pregnancy and at term, using atomic absorption spectrophotometry. The magnesium concentration in umbilical cord blood was higher than in the maternal blood, supporting the existence of an active magnesium transport system. There was also a difference between the magnesium concentration in the amniotic fluid and that in the umbilical cord blood. The magnesium content of myometrium increased from the 32nd week of pregnancy, reaching its maximum level at the 37th week of gestation. Later there was significant decrease in magnesium level until the end of pregnancy. The magnesium content of placental tissue did not change up to the 30th week of pregnancy; however, it then decreased continuously during the last trimester. The significant improvement experienced in certain pathological conditions of pregnancy treatment with magnesium supports the existence of a magnesium deficit induced by pregnancy and the need for magnesium supplementation.

[Comparative morphological studies on the incorporation of various cementless implanted artificial patellas]

Twelve uncemented, artificial patellar components clinically and radiologically without signs of loosening after an implantation period of 9-48 Months were investigated histologically and microradiographically. The components correspond to the system GSB-"old", GSB-"new", PCA and APS. Within the observed implantation period the artificial patellar components GSB-"old", GSB-"new" and PCA showed severe patho-morphological changes of the surrounding tissue and point to loosening. The dowel system according to APS shows after the longest period of time of 14 Months morphologically a fully bony encasement with wide spread direct contacts between the living bone and the metallic Titanium surface. The observation points urgently to the fact, that Polyethylene must not be in direct contact with the bony bed. On the basis of the patho-morphological reactions a partial armament of the polyethylene surface with metallic structures must be rejected as a general principle.

Circulating antineuronal antibodies reach neurons in vivo: an autopsy study

In serum and cerebrospinal fluid of 6 out of 15 patients with small cell lung cancer circulating antineuronal antibodies could be detected by indirect immunofluorescence. None of the patients showed signs of a neurological paraneoplastic syndrome, usually associated with the presence of these antibodies. On sections of frontal brain, cerebellum, dorsal root ganglia and peripheral nerve, obtained at autopsy, a direct immunofluorescence test was performed. Only in antibody-positive individuals were membrane-bound immunoglobulin deposits detected on neurons of dorsal root ganglia and Purkinje cells. The present study showed that circulating antineuronal antibodies reach the central and peripheral nervous system in vivo. These findings support the theory that these antibodies might be directly involved in the pathogenesis of neurological paraneoplastic syndromes.

Morphometric analysis of cartilaginous tumors

144 chondromas and chondrosarcomas have been investigated. Morphometry has been performed: the relative volume density of tumor cell nuclei (Vv%n) and the nuclear area have been measured. The results show that the relative volume density of nuclei is a useful parameter, regarding the localisation of the tumors, to discriminate chondromas and chondrosarcomas, while the nuclear area is no safe criterion to separate these entities.

Long-term reaction of the osseous bed around silicone implants

Between 1970 and 1987, 94 patients received 208 silicone implants at the Department of Orthopaedics, University Hospital, Vienna. Of these, 62.5% were clinically followed up. At follow-up after an average of 116 months, the implant bed was found to be intact in only 41% of cases; in all others we observed lyses around the implant and cysts even in bones at a distance from the operated joint. Histological findings obtained from revision arthroplasty showed a homogeneous picture with foreign-body granulation tissue. These changes were usually clinically inconspicuous and had little effect on patients' subjective well-being. Despite the low discomfort caused, however, the use of such implants in only recommended in critical and severe causes because of the progressive destruction of the osseous bed during the time the implant is in the body.

[Role and possibilities of pathology in the diagnosis of osteoporosis]

Iliac crest biopsy and clinical laboratory investigations are the important criteria to diagnose metabolic osteopathies and osteoporosis. The technic of iliac crest biopsy, the histological technic and the histomorphological and histometric criteria will be discussed. The necessity to compare clinical data with the histomorphology and the importance of surgical pathology, especially osteopathology, will be emphasized.

Fibrous metaphyseal defect

The tendon and ligaments inserted into the perichondrium of the epiphyseal plate were examined in 152 autopsy specimens of tubular long bones. In the region of two areas where tendons were inserted (Ranvier's nodes), the normal medullary tissue is replaced by fibroblastic tissue. A retrospective radiological examination of 155 fibrous metaphyseal defects shows that they are situated at characteristic sites on the circumference of the metaphysis of long tubular bones. This can be related to the insertion of a tendon or ligament near the epiphyseal growth plate which corresponds to areas found in the morphological study and is the site of origin of fibrous metaphyseal defects.

The influence of fibrin sealant on demineralized bone matrix-dependent osteoinduction. A quantitative and qualitative study in rats

Allogeneic demineralized bone matrix (DBM) and bone matrix gelatin (BMG) were implanted with or without fibrin sealant (FS) ectopically (abdominal wall) and orthotopically (7-mm trepanation defect) in 38 male Sprague-Dawley rats. Evaluation was done by descriptive histology, histomorphometry of orthotopic implants, and determination of alkaline phosphatase in ectopic implants. The observation period was 21 days with ectopic implantation and 26 days with orthotopic implantation. In all ectopic specimens, new bone developed without any qualitative difference between specimens with and without FS. The alkaline phosphatase activity did not change significantly upon addition of FS. Morphometry revealed slight differences between the groups with and without FS. The peripheral bone deposits in the BMG + FS group, was significantly larger than in the BMG group. These investigations demonstrated neither a clearly positive nor negative effect of FS on ectopic osteoinduction or BMG-dependent osteoregeneration.

[Is high-density polyethylene suitable as an implant material in cement-free anchoring of hip endoprostheses? A histomorphologic study of an explanted polyethylene screw-in acetabula]

Firmly attached screw-in polyethylene acetabula which had been implanted for between 16 and 54 months were explanted after autopsies and subjected to macroscopic, radiologic and histologic examination. Metaplasias were seen around the threads and on the floor of the acetabulum. Their tendency to ossify represents an attempt at secondary stabilization. Due to the low stability of the polyethylene this causes increased wear on the floor of the acetabulum. The small defects in the polyethylene found in the threads, resembling damage done by mice, may be a sign of biodegradation. In view of the tissue reactions pointed out, the material stability of the polyethylene needs to be improved or implantation must be restricted to a very limited range of indications.

Reactions of surrounding tissue to the cementless hip implant Ti-6Al-4V after an implantation period of several years. Autopsy studies in three cases

Three femoral endoprosthetic stems implanted without cement, made of Ti-6Al-4V alloy, with implantation periods of between 2 and 4 years were examined histologically in the form of undecalcified thin ground sections after having been split into segments and embedded in plastic. During the implantation period total osseointegration in the metadiaphyseal region takes place, while in the proximal area reaction forms with direct contact between metal and bone on the one hand and with an interposed membrane of connective tissue and adjacent secondary bony shell on the other must be distinguished. The osseointegration of the stem is the result of a primary healing of the bone and is due to the biocompatibility of the metal alloy and to the primary stability obtained by the press-fit method.

[Fibrin gluing of the extraocular eye muscles. Experimental use in the rabbit]

An experimental animal study was conducted to determine whether fibrin glue could be used in strabismus surgery (recession, resection, and muscular neurotization). Fibrin glue was used in place of some or all of the commonly used 7-0 Vicryl sutures. In order to evaluate the adhesion of the fibrin glue the rabbits' eyes were enucleated 10-67 days after surgery, fixed in 8% formalin solution and then histologically examined. In the recession and resection specimens a solid joint between muscles and sclera was found, without any significant scar formation or atrophy of the muscles. The muscular neurotization specimens also exhibited a firm connection between the two muscles, with no abnormal loss of muscle fibers by cicatrization or atrophy. In none of the cases did the conjunctiva show any tendency to conglutination. In view of the simplicity of the fibrin gluing technique and the uniform bonding effect, application in human patients is recommended.

Irradiation-sterilization of rat bone matrix gelatin

Bone matrix gelatin induces bone formation in muscle, and when implanted orthotopically it improves bone repair. Co-60 sterilization of bone gelatin impairs the protein-bound induction mechanisms. Gelatin samples nonirradiated or irradiated by 25 or 50 kGy were implanted into a pouch in the abdominal wall of Sprague-Dawley rats, as well as into a 7-mm calvarial defect. Evaluation was done by histologic studies, histomorphometry of orthotopic implants, and determination of alkaline phosphatase in ectopic implants. Gelatin irradiated with 50 kGy was absorbed in the muscle bed without evidence of any specific host reaction. Irradiation of 25 kGy led to histologically confirmed ectopic bone formation, but the wet weight of the explants was only half that of the nonirradiated control samples. Alkaline phosphatase activity was equal in both of these groups. With orthotopic implantation, neither a histologic nor a morphometric effect was seen with 25 kGy. Loss of osteoinduction with 25-kGy irradiation is apparently masked by osteoconductive mechanisms with orthotopic implantation.

[Morphology of the implant site in cemented and uncemented joint implants]

After the insertion of a joint endoprosthesis a healing process is initiated which is comparable to the fracture healing. Thus, a border zone is built up against the implant, being composed of lining cells, connective tissue, vessels, bone marrow and bone. The bone of the implant bed is subjected to a remodeling in order to adapt its structure to the change of the biomechanic stresses. The tissue of the implant bed may react to infection, degradation or wear of the materials and mechanical instability of the fixation as well. The characteristic feature of this reaction is cell and tissue proliferation which causes bone resorption and, possibly, loosening of the implant.

Experimental osteoinduction in rats: collagen-apatite versus osteogenin-containing gelatine

An experimental study in rats was done to investigate the bone-regenerating properties of collagen apatite (Collapat) and to compare it with osteoinduction dependent on osteogenin-containing gelatine (OCG). The test substances were implanted orthotopically (calvarial defect--7 mm in diameter) and heterotopically (paravertebral muscles, abdominal muscles). The results were evaluated histologically and enzymatically (alkaline phosphatase). Collapat caused neither osteoinduction in the heterotopic site nor healing of the bone defects. Foreign body reaction without new bone formation was encountered. OCG implantation leads to new bone formation in the muscles within 3 weeks, associated with a significant increase in alkaline phosphatase activity, and to extensive new bone formation in the calvarial defect within 4 weeks. The defects did not heal if left empty. The value of clinical application of Collapat appears to be doubtful. Osteoinduction with OCG requires further experimental investigation.

Influence of trypsin on the regeneration of hyaline articular cartilage

A purely chondral lesion was inflicted at the medial or lateral femoral condyle of the knee joints of 54 adult male rabbits in order to study hyaline cartilage regeneration. The experimental group was given a sequential intraarticular instillation of trypsin and autologous blood, the control groups were given trypsin or blood or nothing. Only the experimental group (trypsin and autologous blood) showed hyaline cartilage regeneration in 2/3 of the cases examined. Apparently neither the healthy cartilage nor the synovial membrane suffered damage from the trypsin injection. A possible mechanism of cartilage regrowth may be the inhibition of chalones by the fermentative effect of trypsin, which stimulates the aggregation of thrombocytes and fibrin from the injected blood on the chondral lesion, thus initiating the regeneration of hyaline cartilage.

Tissue reactions to titanium endoprostheses. Autopsy studies in four cases

Four cementless prosthetic hip implants of Ti-6Al-4V-alloy with and without longitudinal grooves and Al2O2 ceramic ball heads, with implant periods of 3, 4, 5, and 10 months, were sectioned and examined histologically in undecalcified thin ground sections. Especially on the medial and lateral sides of the prostheses, there was direct bone-to-metal contact without interposed connective tissue, spreading to the dorsal and ventral areas of the prosthesis shaft, which was considered osseointegration. This is based mainly on the technique of implantation with primary stability in the cortical bone by press-fit and on the bioinertness of the titanium alloy. Ungrooved prosthesis areas seem to favor bone growth at the shaft. The secondary bone ring, occurring on the dorsal and ventral areas of the prosthesis, with evidence of further bone remodeling with the passage of time, indicates that osseointegration is a dynamic process that continues to improve prosthetic stability.

[Comparative studies on necrosis susceptibility of capsular tissue in arthrosis and endoprosthetic joint replacement]

We examined the rates of necrosis of newly formed capsula tissue (the number of newly formed capsular tissues with necrosis) after the reoperation of 95 cemented and 11 uncemented total and cup endoprostheses, consisting of different arteficial joint materials. A comparison was made to the joint capsular tissue of 492 patients with arthrosis. The necrosis rate shows a lack of statistical significance within the two year-groups over a period of 12 years and between the different types of prostheses by using PMMA-bone cement. Therefore, it is assumed that a biological equivalence of the prostheses wear products is reached. It is also argued that necrosis can possibly develop from the sudden increased accumulation of PMMA-bone cement particles from the bone bed, caused by the loosening of the prosthesis. In comparison the newly formed capsular tissue of the uncemented prostheses, of which no necrosis was shown, evidence is given that the development of necrosis is chiefly due the quantity of PMMA wear products present. Because of the difficulty to exactly identify the PMMA-bone cement wear products, the toxicity of the PMMA-bone cement--who ist good known and in agreement in recent literature--or its wear products continues to be of hypothetical value in the production of necrosis. This is inspite of the successful detection by the gaschromatograph of the highly toxic paratoliudine in PMMA-bone cement. On the basis of the high statistical significance of the rate of necrosis in comparing the arthrosis joint capsules (14.83%) to the newly formed capsules (73 : 100%) it is shown that the capsulare fibrosis and scar formation to the obliteration of the lymphatic vessels is of secondary importance.