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Biomedical subjects

T Lyberg

Publications and source records attributed to T Lyberg.

At least 109 records · Page 6Linked to original sources
PubMed1994

Toxic effects of methylmethacrylate monomer on leukocytes and endothelial cells in vitro.

The influence of methylmethacrylate monomer (MMA) on the cellular integrity of monocytes, granulocytes and endothelial cells in vitro was investigated. Clinically relevant blood concentrations of MMA (i.e., 5-10 micrograms/mL) were clearly cytotoxic to all cell types studied, as evidenced by the release of lactic dehydrogenase (LD) and 51Cr, and increased uptake of trypan blue (vital staining). Scanning electron microscopic examination of cells treated with 10 micrograms/mL MMA showed marked signs of cytotoxicity after 1 min incubation, and after 30 min the majority of the cells were totally disintegrated. These findings may have clinical bearing on intraoperative cardiorespiratory dysfunction and deep vein thrombosis in MMA-fixed joint replacement surgery.

Bone Cements↗
PubMed1994

Initial interactions of platelets and plasma proteins in flowing non-anticoagulated human blood with the artificial surfaces Dacron and PTFE.

The purpose of the present study was to investigate and to compare the interactions of platelets and proteins in flowing non-anticoagulated human blood with the biomaterials polyethylene-terephthalate (Dacron) and polytetrafluoroethylene (PTFE, Teflon). The respective biomaterials were positioned in a parallel-plate perfusion chamber, and exposed to flowing blood for 5 min at wall shear rates characteristic for veins (100/s), medium sized (650/s) and moderately stenosed arteries (2,600/s). Blood-material interactions were morphologically quantified as platelet-surface adhesion, thrombus volume and fibrin deposition. Platelet adhesion to Dacron was highest at the lowest shear rate (13%) and decreased with increasing shear (4% at 2600/s). In contrast, platelet adhesion to PTFE was shear rate independent (17-19%), and significantly higher than the adhesion to Dacron at 2600/s (P < 0.05). A hallmark of the platelets adherent to PTFE and Dacron was the large percentage of platelets not spread out on the surface. This indicates that both materials were poor platelet activators, even though immunostaining demonstrated the adsorption of the platelet adhesive proteins von Willebrand factor and fibronectin. Adsorption of fibrinogen was also prevailing on both materials. Virtually no thrombi formed on Dacron, while a few small platelet thrombi were observed on PTFE. Less than 1% of the Dacron and PTFE surfaces were covered by fibrin, irrespective of the shear rate. Thus, Dacron and PTFE interact differently with flowing non-anticoagulated human blood, and Dacron is apparently the least thrombogenic material.

Adsorption↗
PubMed1993

Sequential intrapulmonary and systemic activation of coagulation and fibrinolysis during and after total hip replacement surgery.

Hip joint replacement surgery, using acrylic cement for prosthesis fixation, is associated with intraoperative cardiorespiratory dysfunction, and a high frequency of postoperative proximal deep vein thrombosis (DVT). Levels of prothrombin fragments 1+2 (F1+2), tissue plasminogen activator antigen (t-PA), plasminogen activator inhibitor 1 activity (PAI-1), D-dimer and interleukin 6 (IL-6) were measured in arterial (AB) and mixed venous blood (MVB) in five patients during and after total hip replacement operation with acrylic cement prosthesis fixation. Sequential peaks of F1+2, t-PA, PAI-1 and IL-6 appeared, starting with activation of coagulation during preparation of bone, closely followed by activation of fibrinolysis. Later, this was counteracted by an antifibrinolytic response and increase of IL-6. After a fibrinolytic shutdown on the third postoperative day as evidenced by a drop in t-PA and D-dimer concentrations, a second wave of coagulation was seen at the end of the first week. The present model, with frequent sampling of blood entering and leaving the lungs, confirms our earlier findings of the lung as a key organ in promoting coagulation following traumatic activation.

Aged↗
PubMed1993

Treatment with gonadotropins impaired implantation and fetal development in mice.

PURPOSE: The effect of gonadotropins on implantation and fetal development in mice was investigated by superovulation with pregnant mare serum gonadotropin and human chorionic gonadotropin. In a previous study fetal growth was found to be highly retarded. RESULTS: Assessment of implantation in vivo revealed that late implantation did occur. Gestational length was highly extended, the mean number of live fetuses per pregnant mouse was lower and their mean weight significantly reduced. In vitro experiments revealed no significant difference in the rate of blastocyst adhesion and trophoblast outgrowth development. Immunohistochemical staining, however, showed that blastocysts from superovulated mice had smaller trophoblastic outgrowths than control embryos. Staging embryonic development at the time of flushing, however, revealed retarded embryo development in vivo in hormone-treated mice. After correlation with embryonic stage at the beginning of the culture, there was no difference in the size of trophoblastic outgrowths. CONCLUSION: Treatment with gonadotropins impaired implantation and embryonic/fetal development. Changes in maternal milieu, rather than in embryo quality, may be responsible for the adverse effects observed.

Animals↗
PubMed1993

Temporomandibular joint dysfunction and facial pain caused by neoplasms. Report of three cases.

The most frequent causes of painful limitation of temporomandibular joint function are myofascial pain dysfunction or anterior disk displacement. A potential problem in dealing with those patients is the risk of misdiagnosing the rare patient who has a neoplastic disease, primary or metastatic to the epipharyngeal region, parotid gland, jaws, or temporomandibular joint. Three cases are presented in which progressively worsening limitation of mandibular movement and increasing pain led to the diagnosis of a neoplasm in the temporomandibular joint region. The article illustrates the necessity of performing a thorough clinical and radiographic examination.

Adult↗
PubMed1993

In vivo deterioration of proplast-teflon temporomandibular joint interpositional implants: a scanning electron microscopic and energy-dispersive X-ray analysis.

The surgical treatment of internal derangements of the temporomandibular joint (TMJ) often involves disc removal. Alloplastic interpositional implants for disc replacement have been widely used to avoid the development of osteoarthritic changes in the TMJ. This study reports the in vivo wear characteristics of Proplast-Teflon (Vitek Inc, Houston, TX) interpositional implants (PTIPI) in 12 patients who had their implants for 13 to 71 (mean 54.6 +/- 5.8 SEM) months. In all cases, changes in the condyle and fossa were found resulting from resorption and replacement of the articulating bone by granulomatous tissue. All implants showed significant signs of wear, such as thinning, cracks, and tears, and overt perforations were seen in five cases. Scanning electron microscopy (SEM) combined with energy-dispersive x-ray microanalysis (EDAX) showed numerous microfragments of the PTIPI in the peri-implant soft tissues. Microfragments were demonstrated by their aluminum content. In addition to the inflammatory foreign-body reaction, it is suggested that there also were toxic and hypersensitivity reactions to aluminum involved in the pathogenesis of the bone destruction.

Adult↗
PubMed1993

Location of plasminogen activator (PA) and PA inhibitor in human colorectal adenocarcinomas.

Both the coagulation and fibrinolytic cascades generate proteolytic enzymes which appear to be essential for tumor invasion. In the present investigation adenocarcinomas and normal colon from 14 patients with colorectal cancer were studied by immunohistochemistry. The most striking observation was an enrichment of plasminogen activator inhibitor in the tumor tissue, whereas no such immunoreactivity was detected in the biopsies of normal colon. The tumor-host interface was characterized by a massive accumulation of inflammatory cells, macrophages and T lymphocytes. In this area fibrin(ogen) immunoreactivity as a sign of local activation of the coagulation cascade was also seen. The transition zone between the tumor and normal tissue was furthermore characterized by a marked enrichment of urokinase plasminogen activator immunoreactivity. The study strongly indicates that proteases and inhibitors of the fibrinolytic system may be of great importance in tumor invasion.

Adenocarcinoma↗
PubMed1993

Histological studies on postischemic rat skeletal muscles. With emphasis on the time of leukocyte invasion.

Several studies have suggested that the damage after ischemic injuries increases during reperfusion and that this reperfusion damage is mediated through granulocytes which invade the damaged area. The present study was undertaken to test these hypotheses by histological investigations of the anterior tibial muscles in a rat hind limb tourniquet model after 4.5 h of complete ischemia and graded periods of reperfusion. Uptake of albumin into damaged muscle fibers was demonstrated immunohistochemically and used to determine the extent of the ischemic lesions. The size of the lesions was measured morphometrically on immunostained sections from paraffin-embedded material. Granulocytes in and outside the capillaries were counted on slides from historesin-embedded material. Generally, there was a compact central area in the muscles which showed necrosis of all fibers and many capillaries, little interstitial edema, and little or no invasion of granulocytes or macrophages. The central core did not increase in size during the postoperative period. Outside this are there was a zone of partial tissue destruction with quite marked interstitial edema. This zone also remained unchanged in size but it is uncertain whether the number of necrotic fibers increased with time. There was an increasing invasion of granulocytes in this outer zone from 5 to 24 h after release of the occlusion and monocyte/macrophage invasion was seen from 48 h. Outside this zone there was a subfacial zone with normal muscle fibers in all cases. It is concluded that the central area of complete tissue destruction was present at the time of release of the occlusion and did not increase in size during the further postoperative course. There was no indication that granulocytes participated in this damage. The extent of the partially damaged area also remained unchanged during the postoperative course. It is conceivable that granulocytes aggravated the lesions by increasing the number of necrotic fibers in this peripheral area but not before 5 h after release of the occlusion. This is later than described in previous studies.

Animals↗
PubMed1993

Endotoxin liberation from Neisseria meningitidis correlates to their ability to induce procoagulant and fibrinolytic factors in human monocytes.

Endotoxin released from different strains of Neisseria meningitidis were studied for their ability to induce procoagulant (tissue factor, TF), fibrinolytic (plasminogen activator, PA) and antifibrinolytic (plasminogen activator inhibitor 2, PAI-2) factors in human monocytes. Two meningococcal strains that liberate endotoxin (E+; 270+ and 840+) and 2 non-liberating (E-; 270- and 840-) strains were used. The endotoxin activity in culture filtrates of these strains was monitored with the Limulus amoebocyte lysate (LAL) test. There was a marked difference between E+ and E- strains in their ability to liberate endotoxin. Suspensions of whole bacteria of all 4 strains induced a significant (14-19-fold) increase in monocyte TF expression when present in concentrations > 10(5) CFU/ml. At lower concentrations (10(4) CFU/ml), E+ strains were clearly more potent stimulators of TF synthesis than E- strains. Culture filtrates of E+ strains were up to 10(4)-fold more potent in inducing TF synthesis than filtrates from E- strains. This marked difference in inducing potency between E+ and E- strains was also observed when monocyte PAI-2 synthesis was examined. The PA expression, on the other hand, was suppressed when monocytes were incubated in the presence of culture filtrates, especially filtrates from the E+ strains. The increased procoagulant and antifibrinolytic activity, together with reduced profibrinolytic activity of monocytes, was closely correlated to the amount of endotoxin measured in the culture filtrates. These changes may contribute substantially to the coagulopathic state seen during systemic meningococcal disease.

Cells, Cultured↗
PubMed1992

[Indirect measurement of intramucosal pH in the gastrointestinal tract using a tonometer. A useful marker of tissue oxygenation in critically ill patients].

Multiple organ failure may develop as a consequence of defective tissue oxygenation, particularly in the gut. Measurements of intramucosal pH (pHi), accomplished by means of a tonometer placed in the stomach or in the sigmoid colon, seem to monitor the degree of mucosal oxygenation very good. The tonometer technique is noninvasive and easy to perform. pHi may be useful as an index to guide therapeutic interventions in critically ill patients.

Critical Care↗
PubMed1992

Glossopexia--evaluation of a new surgical method for treating obstructive sleep apnea syndrome.

Uvulopalatopharyngoglossoplasty, UPPGP, is a modification of the uvulopalatopharyngoplasty, UPPP, technique, originally used for surgical treatment of the obstructive sleep apnea syndrome. The first method seems to be the more successful. However, polysomnography performed after UPPGP showed that about 35% of the patients still had obstructive apnea periods during sleep. Eight of these patients were reoperated with a new technique which is a combination of partial tongue resection and anterior suspension of the tongue (glossopexia). After glossopexia all the patients were subjectively relieved of their symptoms. However, polysomnography carried out postoperatively demonstrated that only 2 patients were objectively cured. The authors want to stress the necessity of meticulous polysomnographical registration pre- and postoperatively. Subjective and objective parameters recorded before and after surgery are discussed.

Airway Obstruction↗
PubMed1992

Palatopharyngoglossoplasty in the treatment of patients with obstructive sleep apnea syndrome.

A new technique (palatopharyngoglossoplasty (PPGP)) has been developed for surgical treatment of patients with the obstructive sleep apnea syndrome (OSAS). In 20 operated patients 18 reported immediate marked improvement of daytime sleepiness, alertness and vigilance during the day, and of working capacity. However, polysomnography carried out pre- and postoperatively showed that only 10 patients were "cured", defined as 50% or more reduction in apnea/hypopnea index (AHI). Cephalometric analysis pre- and postoperatively indicated that nonresponders had a long and narrow posterior airway space, and we suggest that during sleep this part of the upper airway collapses before as well as after the operation. The discrepancy between the subjective improvement observed after PPGP and the postoperative reduction in AHI may be due to reduced/eliminated snoring and/or improvement in sleep quality after the operation.

Adult↗
PubMed1991

Generation of procoagulant (thromboplastin) and plasminogen activator activities in peripheral blood monocytes after total hip replacement surgery. Effects of high doses of corticosteroids.

Development of thromboplastin (tpl) and plasminogen activator (PA) activity in monocytes and the effects of high doses of corticosteroids (HCD) on these activities were studied in patients undergoing a standardized surgical trauma. Twelve patients who received uncemented total hip prostheses were divided into a nonsteroid group (n = 6) and a steroid group (n = 6). We found no significant differences between the two patient groups regarding tpl or PA activities of peripheral blood mononuclear cells (PBM) isolated during the postoperative phase. However, in the nonsteroid group there was a tendency for increased expression of procoagulant activity and decreased fibrinolytic activity on the 1st postoperative day, favoring the formation of fibrin in the monocyte microenvironment. Further, PBM isolated on the 1st and 2nd day after surgery were significantly less capable of generating tpl activity on endotoxin stimulation than cells isolated preoperatively. This was not the case in the steroid group. These patients had also a tendency for decreased fibrinolysis at the end of the 1st postoperative week, indicating increased imbalance towards a more thrombotic stage after surgery.

Adrenal Cortex Hormones↗
PubMed1991

Extraoral subcondylar ramus osteotomy for correction of mandibular prognathism. The surgical technique and complications.

1178 patients with mandibular prognathism and/or asymmetry, in some cases combined with maxillary retrognathism, were treated by extraoral horizontal or oblique ramus osteotomy during the period from 1939 to 1989. The described percutaneous retromandibular approach is a simple, rapid and reliable technique which can usually be performed under local anaesthesia. Very few complications, particularly neurological, were observed. These aspects justify consideration of this technique when indications for a simple, straight set-back procedure of the mandible exist, and there is no tendency to bite-opening. However, the method demands intermaxillary fixation for 6-9 weeks postoperatively.

Adolescent↗
PubMed1991

The vascularized fibular flap for mandibular reconstruction.

Vascularized fibular bone grafts have advantages over other bone grafts in the restoration of the contour and function of defective mandibles. The fibular graft can be tailored to fit even major mandibular defects; in combination with preformed temporomandibular joint prostheses total mandibular reconstruction can be performed in a single procedure. The fibular transplant is considered ideal for the insertion of implants to support dental suprastructures to obtain maximal oral rehabilitation. We have used fibular grafts in eight cases for primary or secondary reconstruction of a variety of mandibular defects resulting from cancer, chronic osteomyelitis or gunshot injuries. The results have been most encouraging with respect to function and cosmetic appearance. There have been no transplant failures and minimal donor site complications.

Adolescent↗
PubMed1991

Immunohistochemical localization of coagulation, fibrinolytic and antifibrinolytic markers in adenocarcinoma of the lung.

Extravascular coagulation and fibrinolysis are intimately involved in and modulate cancer cell growth, invasion and metastasis. Samples from resection specimens of patients with primary lung cancer (adenocarcinomas) were tested with monoclonal (MAb) and polyclonal (PAb) antibodies against various factors of the coagulation or fibrinolysis systems, or against antigens of inflammatory or proliferating cells. MAb Ki-67 specific to nuclear antigens of proliferating cells showed a distinct but variable staining of cell nuclei throughout the tumor tissue. Nests of tumor tissue stained with cytokeratin-specific antibodies (PKK1), whereas other parts were negative. Fibrin(ogen) and fibronectin were found throughout the tumor tissue stroma and in the alveolar lining, and the most densely stained areas were at the transition zone between normal and tumor tissue. Fibrinolytic system components like tissue plasminogen activators (t-PA), and urokinase (u-PA), and their inhibitors PAI-1 and PAI-2 were all studied. All specimens were negative for t-PA (except endothelial linings), whereas urokinase-specific antibodies stained loosely packed tumor cells and macrophages within the tumor stromal tissue and alveolar septa. Both PAI-1 and PAI-2 were most prominently expressed within interstitial and alveolar macrophages. A weaker staining of tumor tissue cells was demonstrated. Inflammatory cells like macrophages and T lymphocytes were located in aggregates or diffusely spread within tumor stromal tissue. The inflammatory reaction was most intense at the border between normal lung and tumor tissue.

Adenocarcinoma↗
PubMed1991

Changes in leukocyte subpopulations following total hip replacement surgery. Effects of high doses of corticosteroids.

Changes in leukocyte subpopulations and the effects of high-dose corticosteroids (HDC) on these changes were studied in patients undergoing total hip replacement surgery. Twelve patients were randomly divided into a non-steroid (n = 6) and a steroid group (n = 6). The steroid patient group was treated with HDC. In the non-steroid group, we found a leukocytosis, monocytosis, lymphocytopenia and granulocytosis after surgery in local anaesthesia. Only the changes in granulocyte counts were significant. Furthermore, the relative proportion of pan T-cells, helper/inducer T-cells, suppressor/cytotoxic T-cells, B-cells, activated T-cells and natural killer-cell subset did not change significantly during the post-operative course. Thus, lymphocytopenia was caused by reduced absolute counts of all these subsets. However, there was a tendency for decreased relative proportions of pan T-cells, inducer/helper T-cells, activated T-cells and natural killer (NK) cell subset in the early postoperative phase. Treatment with HDC significantly raised the numbers of leukocytes and granulocytes and decreased the lymphocyte and monocyte counts in the first 2 days after surgery, accounting for significant differences between the two patients groups. The percentage of pan T-lymphocytes was significantly lower in the steroid patient group on days 1 and 2 after the operation. There was no significant difference between the two patient groups with regard to the percentages of B-lymphocytes, T-lymphocyte subsets, NK cell subset, leu M3 cells and helper:suppressor ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗