Dynamic three-dimensional finite element analysis of orbital trauma.

This study comprises a dynamic finite element (FE) analysis of the mechanisms of orbital trauma, specifically buckling and hydraulic theories. A digital model of the orbital cavity - including the eyeball, fatty tissue, extraocular muscles, and the bone orbit - was created from magnetic resonance imaging and computed tomographic data from a real patient. An impactor hit the FE model following two scenarios: one was a hydraulic mechanism for direct impact to the eyeball and the other a buckling mechanism for direct impact over the infraorbital rim. The first principal stress was calculated to determine the stress distribution over the orbital walls. The FE model presented more than 900,000 elements and time of simulation was 4.8 milliseconds (ms) and 0.6 ms, for the hydraulic and buckling mechanisms, respectively. The stress distribution in the hydraulic mechanism affected mainly the medial wall with a high stress area of 99.08 mm2, while the buckling mechanism showed a high stress area of 378.70 mm2 in the orbital floor. The presence of soft tissue absorbed the energy, especially in the hydraulic mechanism. In conclusion, the applied method of segmentation allowed the construction of a complete orbital model. Both mechanisms presented results that were similar to classic experiments. However, the soft tissue in the hydraulic mechanism absorbed the impact, demonstrating its role in orbital pathophysiology.

Finite element evaluation of three methods of stable fixation of condyle base fractures.

The surgical treatment of mandibular condyle fractures currently offers several possibilities for stable internal fixation. In this study, a finite element model evaluation was performed of three different methods for osteosynthesis of low subcondylar fractures: (1) two four-hole straight plates, (2) one seven-hole lambda plate, and (3) one four-hole trapezoidal plate. The finite element model evaluation considered a load applied to the first molar on the contralateral side to the fracture. Results showed that, although the three methods are capable of withstanding functional loading, the lambda plate displayed a more homogeneous stress distribution for both osteosynthesis material and bone and may be a better method when single-plate fixation is the option.

Accuracy improvement in Cranio-Maxillofacial soft tissue simulation using a muscle embedded meshing approach.

In the presented paper, we propose to improve the state-of-the-art approach for Cranio-Maxillofacial (CMF) soft tissue simulation by considering a new image-based meshing approach that accurately models the interface between different tissue types. The proposed approach has been initially evaluated on soft tissue deformations of four patients undergoing CMF surgery using post-operative CT scans. The results indicate improved prediction and robustness of the surgical planning outcome when compared to the state-of-the-art method while decreasing the simulation time.

[Speech outcome after simple and multiple cleft palate operations]. / Sprechsprachliche Ergebnisse nach einfachen und mehrfachen Gaumenverschlussoperationen.

OBJECTIVES: If the primary palatal closure in a patient with cleft lip and palate is unsuccessful, defects such as palatal fistulas and a short velum have to be corrected by secondary operations. It is an informal belief among surgeons that these reoperations can have detrimental effects on the patients' nasal resonance and articulation. It was our aim to critically evaluate the validity of this belief. MATERIAL AND METHODS: One hundred and twenty-four patients with cleft lip and palate were divided into three groups. The 70 patients in group 1 had only undergone a primary palatal closure operation. The 33 patients in group 2 had undergone one or more palatal reoperations. The 21 patients in group 3 had undergone an additional pharyngeal flap operation. Resonance and articulation were evaluated perceptually. Nasalance was assessed with the NasalView system, and the mean speech rate was analyzed with the MODIAS software. RESULTS: There were no significant differences for any of the speech measures between groups 1 and 2. Patients in group 3 had significantly worse results for all speech measures. CONCLUSIONS: The speech outcomes for patients with multiple palatal reoperations were no different from those of patients with single palatal closure operations. The pharyngeal flap operation did not lead to sufficient improvements in the speech of the patients in group 3.

Activation of human neutrophils by electronically transmitted phorbol-myristate acetate.

We report the transfer of the activity of 4-phorbol-12-beta-myristate-13-acetate (PMA) by electronic means. Neutrophils were placed at 37 degrees C on one coil attached to an oscillator, while PMA was placed on another coil at room temperature. The oscillator was then turned on for 15 min, after which cells were usually further incubated for up to 45 min at 37 degrees C before measurement of reactive oxygen metabolites (ROMs) production. In 20 blind experiments, PMA thus 'transmitted' induced ROM production. ROM were not induced when: (1) PMA vehicle or 4-alpha-phorbol 12,13-didecanoate (an inactive PMA analogue) were transmitted; (2) the oscillator was switched off; (3) superoxide dismutase or protein kinase C inhibitors were added to cells before transmission. These results suggest that PMA molecules emit signals that can be transferred to neutrophils by artificial physical means in a manner that seems specific to the source molecules.

[Plasma amino acid concentrations and isoleucine-phenylalanine quotient in patients with acute myocardial infarct during amino acid infusion]. / Plasmaaminosäurekonzentrationen und Isoleucin-Phenylalanin-Quotient bei Patienten mit akutem Myokardinfarkt unter Aminosäuresubstitution.

AIM: The influence of substitution with two different amino acid solutions on changes in plasma amino acids were studied in patients with acute myocardial infarction. PATIENTS AND METHODS: Thirty consecutive patients admitted to an intensive care unit were included in this open, nonrandomized study. The isoleucine-phenylalanine-concentration ratio was calculated. Patients of the treatment groups received 10 ml/kg BW/24 h of 10% amino acid solutions intravenously (1 g/kg BW/24 h). Patients of group 1 received Intrafusin 10%, patients of group 2 Aminosteril 10%. Ten patients (group 3) were infused with 10 ml/kg BW/24 h isotonic electrolyte solution (Jonosteril and served as a control group. All infusions were performed over a 96 hour period. RESULTS: All infusion of amino acid solutions increased the plasma concentrations of most amino acids without a significant impact on the pattern of amino acids over time. Significant increases in plasma concentrations together with a significant variation over time were observed for glycine, isoleucine, proline, alpha-amino-butyric-acid and glutamine. A significant difference in relation to the type of amino acid solution was observed for isoleucine and proline (rapid increase and higher concentrations with Aminosteril), and glutamine (rapid increase and higher levels with Intrafusin). CONCLUSION: The isoleucine-phenylalanine-ratio increased from initially decreased values between 0.9 and 1.0 during amino acid infusion and reached the level of 1.25 found in healthy persons in patients with Intrafusin infusions.

New aspects on etiology, biochemistry, and therapy of portal systemic encephalopathy: a critical survey.

There is scientific agreement that portal systemic encephalopathy (PSE) is caused morphologically by portal systemic shunts and biochemically by constituents of the portal venous blood. Ammonium has a key role in the pathogenesis of PSE. Direct correlations with the degree of PSE have been established exclusively with glutamine, i.e. the terminal product of the peripheral detoxification of ammonium. In PSE, ammonium is probably responsible for damage to astrocytic and neuronal cells. Ammonium's toxic effect is due to the intracerebral glutamine synthesis. After several metabolic steps, which will be discussed in detail, brain cell damage is caused directly or indirectly (exitotoxically) by energy deficiency. Hyperammonemia and PSE are each well defined though different forms of disturbance. Therefore, ammonium is not the sole decisive factor in the pathogenesis of PSE. We performed a detailed and critical analysis of all studies on amino acid therapy of PSE, especially those that were randomized and controlled. This analysis revealed a close and direct correlation between qualitative and quantitative dosages of amino acids on one hand, and parallel improvements of amino acid imbalance (essentially associated with PSE) and degree of PSE on the other. A close and direct dose/efficacy correlation must be assumed. Disturbed plasmatic amino acid homeostasis and cerebral monoaminergic neurotransmission are probably important pathogenic factors of PSE. A fundamental cofactor in the efficacy of each adequate amino acid therapy might be a substantial decrease of endogenous ammonium production. Physiologic benzodiazepines may also have an important function in the pathogenesis of PSE: not so, however, the glutamate-ergic and GABA-ergic neurotransmission, which are disturbed principally in PSE. In close correlation to pathogenesis, established and proposed therapies of PSE are critically discussed.

[Different evaluations of the staging of Hodgkin's and non-Hodgkin's lymphomas (NHL) with computer tomography and lymphography by different observers]. / Unterschiedliche Beurteilung der Stadieneinteilung des Hodgkin- und Non-Hodgkin-Lymphomes (NHL) mit Computertomographie und Lymphographie durch verschiedene Untersucher.

In this report, the differences in the evaluation of CT and lymphography findings by different observers is discussed. The study included 132 men and 79 women (146 NHL and 65 Hodgkin lymphomas). A total of 185 CT examinations and 78 lymphographies were available for reevaluation. In the lymphographies, discongruent findings were reported twice as frequently as in the CT scans (15% and 9%). An optimized examination protocol for CT and consistent criteria for the interpretation of lymphographic findings could possible lead to a better diagnostic evaluation.

[Behavior of plasma proteins and nitrogen balance in patients with acute myocardial infarct with and without intravenous amino acid administration]. / Verhalten von Plasmaproteinen und Stickstoffbilanz bei Patienten mit akutem Myokardinfarkt mit und ohne intravenöse Aminosäurezufuhr.

OBJECTIVE: The goal of this study was to examine the behaviour of nitrogen balance and plasma proteins with or without intravenous supply of amino acids in patients with acute myocardial infarction. DESIGN AND PATIENTS: 30 consecutive patients who suffered from acute myocardial infarction and who were admitted to our medical intensive care unit were examined in an open, non-randomised study. SETTING AND INTERVENTIONS: The first 10 patients (group I) received 10% Intrafusin 10 ml/kg BW/24 h as a continuous intravenous infusion over a period of 96 h. Patients No. 11-20 (group II) received Aminosteril 10% 10 ml/kg BW/24 h also over a 96-hour period. Patients No. 21-30 (group III) were given intravenous infusions of Jonosteril 10 ml/kg BW/24 h for 96 h. RESULTS: The nitrogen balance demonstrated a statistically significant decrease in all groups (group I, 9.1 to 6.1 g/day; group II, 9.8 to 4.8 g/day; group III, 1.3 to -1.1 g/day); however, in groups I and II the nitrogen balance remained positive. The concentrations of total protein, transferrin, retinol-binding protein and pre-albumin decreased significantly. This decrease, however, was significantly less in patients given amino acid infusions. CONCLUSIONS: Infusion of amino acids in acute myocardial infarction results in a positive nitrogen balance and reduces the decrease in plasma protein concentrations. Further studies are required to judge the positive nutritive effect of amino acid infusions on the outcome of myocardial infarction.

Immunoregulatory functions of paf-acether. IX. Modulation of apoptosis in an immature T cell line.

We investigated the ability of a phospholipid cytokine, paf-acether to modulate programmed cell death in an immature human T cell line CEM-C12. Paf-acether alone did not cause cell death, but when it was added to CEM-C12 cells in the presence of calcium ionophore, a marked increase in cell mortality and DNA fragmentation was observed compared with calcium ionophore alone. This effect was dose-dependent between 2 and 10 microM paf-acether and specific in that lysophosphatidylcholine had a minimal effect. Thus, in association with another signal, paf modulates apoptotic processes in an immature human T cell line. This may be relevant to intrathymic lymphocyte maturation.

Cell adhesion by membrane-bound paf-acether.

It was recently shown that paf-acether (paf) synthesized in different cell types remains partly cell-associated. In the present work, we tested the hypothesis that cell-associated paf might in fact remain exposed on the external plasma membrane and be able to exert its biological functions. Human polymorphonuclear neutrophils (PMN), stimulated with either opsonized zymosan or ionophore A23187 and then thoroughly washed, induced aggregation of human and rabbit platelets in a time- and dose-dependent manner, whereas no aggregation was observed in the presence of unstimulated cells. Aggregation was inhibited by the specific paf antagonists BN 52021 or WEB 2086. Treatment of stimulated PMN with specific anti-paf antibody before addition to platelets abolished the PMN--paf-mediated aggregation. Microscopic observation of human platelets revealed that aggregates formed by platelets were attached to the neutrophil surface. Paf remained associated with PMN following human PMN-human platelet interaction, in contrast to human PMN-rabbit platelet incubation, where it disappeared from both PMN and platelet surfaces. Our results strongly support the hypothesis that a fraction of cell-associated paf synthesized in neutrophils is located on and/or in the external plasma membrane, where it can act upon other cells by direct cellular contact. Such a mechanism of cell adhesion might play a role in cell physiology (neutrophils but also monocytes/macrophages, eosinophils, and lymphocytes), as well as in the onset and perpetuation of immune and inflammatory reactions.

[Taurine--recent views and importance for artificial feeding]. / Taurin--neuere Aspekte und Bedeutung für die künstliche Ernährung.

Taurine is an important age- and compartment-specific part of the pool of free amino acids in all human tissues and fluids examined. Besides an active taurine transport system, the mechanisms to assure compartment-specific taurine-homeostasis in humans is presumably due to a compartment-specific taurine synthesis. By the identity of cysteine-sulfinic acid - and glutamate-oxalate transaminase as well as of cysteine-sulfinic acid - and glutamic acid decarboxylase taurine biosynthesis via cysteine-sulfinic acid shows direct metabolic relationship between biochemical pathway of cysteine-sulfinic acid and taurine on one side, and of the dicarbonic acid and their biological decarboxylates on the other side. In the parenteral and enteral nutrition of premature babies as well as of adults with portosystemic encephalopathy or with extreme thiamine deficiency, there is - besides an inconstant parallel of exogenous taurine supply and plasma taurine homeostasis - a constant parallel between definitely lowered plasma taurine concentrations and comparably distinct disturbance of the homeostasis of the dicarbonic acids and/or their biosynthetic products. A metabolic connection seems likely. The hypothesis of Sturman et al. in 1976 that taurine is an essential part of the human nutrition at least in the premature or full-term newborn phase of life could not be supported in the subsequent studies of different groups of authors - neither in relation to the nitrogen balance, childhood-development, hepatic cellular function, biliary-acid metabolism, intestinal fat absorption nor any organ-specific function. The nutritional value of taurine in humans still remains unclear in regard to specific physiologic as well as specific pathophysiologic phase of metabolism.

[Branched-chain amino acids in the treatment of latent porto-systemic encephalopathy. A placebo-controlled double-blind cross-over study]. / Verzweigtkettige Aminosäuren bei der Behandlung der latenten portosystemischen Enzephalopathie. Eine placebokontrollierte Doppelblind-Cross-over-Studie.

In a doubleblind cross-over placebo-controlled trial the efficiency of oral treatment with branched chain amino acids was investigated in 22 inpatients with liver cirrhosis. In all patients evidence of latent (subclinical) portalsystemic encephalopathy was obtained by using an extensive psychometric test programme. Patients received a defined diet of 35 cal/kg/day containing 1 g of protein. In addition, branched chain amino acids or casein in a dosage of 0.25 g/kg/day was administered in a cross-over fashion, each for 1 week. Semiquantitative nitrogen balance increased during both treatments, with a tendency towards a larger increase during branched chain amino acid treatment. At the same time ammonia concentration tended to decrease during branched chain amino acid treatment. Taking into account the cross-over design, significant improvements attributable to branched chain amino acid treatment could be demonstrated in psychomotor functions (line tracing, tapping, steadiness, auditory reaction time), attention (digit table), and practical intelligence (digit symbol, number connection test).

Branched chain amino acids in the treatment of latent portosystemic encephalopathy. A double-blind placebo-controlled crossover study.

Branched chain amino acids have been recommended for the treatment of portosystemic encephalopathy based on the false neurotransmitter hypothesis. This hypothesis implies that by correction of the deranged amino acid pattern in the blood of cirrhotics, false neurotransmission and then portosystemic encephalopathy is improved. We conducted a double-blind crossover placebo-controlled trial in 22 inpatients with liver cirrhosis and obtained evidence of latent (subclinical) portosystemic encephalopathy using an extensive psychometric test program. Patients received a defined diet of 35 cal/kg X day containing 1 g of protein. In addition, branched chain amino acids or casein in a dosage of 0.25 g/kg X day was administered in a crossover fashion, each for 1 wk. Semiquantitative nitrogen balance increased during both treatments, with a tendency of a larger increase during branched chain amino acid treatment. At the same time ammonia concentration tended to decrease during branched chain amino acid treatment. Taking into account the crossover design, significant improvements attributable to branched chain amino acid treatment could be demonstrated in psychomotor functions (line tracing, tapping, steadiness, auditory reaction time), attention (digit table), and practical intelligence (digit symbol, number connection test).

[Animal experiment studies of chronic thiamine deficiency. Changes in carbohydrate and amino acid metabolism under resting and load conditions]. / Tierexperimentelle Studie zum chronischen Thiaminmangel. Veränderungen des Kohlenhydrat- und Aminosäurenstoffwechsels unter Ruhe- und Belastungsbedingungen.

The metabolic effects of thiamine deficiency on the metabolism of lactate, acid-base and amino acids were evaluated both with and without muscular exercise in a controlled animal experiment. Thiamine deficiency - in good correlation with its biologic halftime and also with reports in the literature - caused with a latency of 17-56 days and statistically proven in parallel the following effects: hyperlactemia; in comparison to controls elevated plasma concentrations of threonine, alanine, glutamic acid, glutamine, histidine, methionine, taurine, valine, isoleucine and leucine; distinctly lowered - also in comparison to controls - plasma concentrations of arginine and tryptophan. Furthermore, in the thiamine deficient rats predetermined muscular exercise caused the following effects, also occurring concomitantly: life threatening lactacidosis; marked - statistically prover - disturbance of the homeostasis of alanine, glycine, methionine and arginine; distinctly - and statistically significant - elevated plasma concentration of proline; statistically significantly lowered plasma concentrations of taurine. The reasons for all these changes under thiamine deficiency is most likely a metabolic one primarily due to a disturbance of the utilization of pyruvate in the liver. An additional disturbance of both the transsulfuration pathway and the Krebs-Henseleit-cycle seems probable. The physiologic regulation of pyruvate, lactate, alanine, serine and tyrosine during muscular exercise in correlation to the controls is being discussed.

Late metastases of a hypernephroma to the thyroid and the pancreas.

A case of late metastasis of a hypernephroma to unusual localizations is presented. The radiological features are reviewed. In patients with a hypernephroma, the possibility of a late onset of metastasis has to be considered.