Dysgnathia, orthognathic surgery and spinal posture.

The aim of this study was to evaluate the spine by video rasterstereography before and after orthognathic surgery. Twenty-nine patients (17 patients with a skeletal class III, 7 patients with a skeletal class II, and 5 patients with mandibular asymmetry) were evaluated preoperatively and 1 year postoperatively. Video rasterstereography is a method of back surface measurement and shape analysis using the moire topography. Orthognathic surgery in cases of class III and asymmetry did not lead to significant changes in body posture. In class II patients it led to some changes in body posture, but without orthopaedic consequences. It is concluded that orthognathic surgery causes minimal or no change in body posture.

Age predicts outcome of high-tibial osteotomy.

This study compares the predictive value of age at surgery in high tibial osteotomy. Twenty-seven high-tibial osteotomies in patients who are 65 years or older (mean age at surgery 68+/-4 years, follow up 12+/-2 years) were compared to 67 osteotomies in patients younger than 65 years (mean age at surgery 56+/-6 years, follow up 13+/-3) with respect to the outcome by Cox regression analysis. Failure, i.e. endpoint, was defined as implantation of a knee endoprosthesis and assessed by Kaplan-Meier analysis. There is a significantly higher risk for failure of high tibial osteotomies in patients of 65 years or more compared to younger patients (failure rate 38.4+/-11.3% vs. 23.1+/-5.8%) resulting in a relative risk of 1.5 (P=0.0461). The hazard of failure increased 7.6% per year of age. We conclude that in regard to the increasing risk of failure per year of age and the higher failure rate in older patients, high-tibial osteotomy should not be performed on patients older than 65 years.

[Minimal invasive stabilization of osteoporotic vertebral compression fractures. Methods and preinterventional diagnostics]. / Minimal-invasive Stabilisierung osteoporotischer Wirbelkörpereinbrüche. Methodik und präinterventionelle Diagnostik.

PURPOSE: Minimal invasive stabilizations represent a new alternative for the treatment of osteoporotic compression fractures. Vertebroplasty and balloon kyphoplasty are two methods to enhance the strength of osteoporotic vertebral bodies by the means of cement application. MATERIAL AND METHODS: Vertebroplasty is the older and technically easier method. The balloon kyphoplasty is the newer and more expensive method which does not only improve pain but also restores the sagittal profile of the spine. RESULTS: By balloon kyphoplasty the height of 101 fractured vertebral bodies could be increased up to 90% and the wedge decreased from 12 to 7 degrees. Pain was reduced from 7.2 to 2.5 points. The Oswestry disability index decreased from 60 to 26 points. This effect persisted over a period of two years. Cement leakage occurred in only 2% of vertebral bodies. Fractures of adjacent vertebral bodies were found in 11%. CONCLUSION: Good preinterventional diagnostics and intraoperative imaging are necessary to make the balloon kyphoplasty a successful application.

Intraoperative dissemination of tumour cells in patients with Ewing tumours detected by RT-PCR.

Using reverse transcriptase polymerase chain reaction (RT-PCR) we evaluated the occurrence of tumour-cell ribonucleic acid (RNA) in the blood during surgery in patients with Ewing tumours. The patients received irradiation and chemotherapy according to the protocol of the European Intergroup Cooperative Ewing Sarcoma Study (EICESS) 92. Blood samples were taken from 15 patients. Intra-operative dissemination was found during 2/8 resections but showed no relation to patient survival. At second-look biopsy, detection of tumour-cell RNA was associated with relapse and metastases in 3/4 patients. The results suggest that pre-operative treatment did not completely prevent dissemination of tumour cells during surgery of Ewing tumours.

[Minimally invasive therapy of painful osteoporotic vertebral fractures]. / Minimal-invasive Therapie osteoporotischer Wirbelkörperfrakturen.

INTRODUCTION: Osteoporosis is the most common bone disease. Due to an increase of the older population an higher impact of osteoporosis and its treatment can be expected. BACKGROUND: Painful osteoporotic vertebral fractures result in an increased morbidity and mortality. Standard treatment of painful osteoporotic vertebral fractures comprises analgetics, bed rest and, if needed, orthotics. METHOD: By mere augmentation of the vertebra with polymethylmet acrylate (PMMA), the so called "vertebroplasty" a good pain reduction and increase in function and quality of life can be achieved. With the technique of kyphoplasty (Kyphon) it is feasible to correct a kyphotic deformity. Inflatable balloons are introduced to the vertebra to lift the endplates. The created cavity is filled with bone cement (PMMA). DISCUSSION: Kyphoplasty is able to correct osteoporosis induced kyphotic deformity. Compared to the technique of vertebroplasty, kyphoplasty is less risky but is more time consuming and more expensive. Time will show whether the expected advantage of deformity correction will result in a better outcome for the patient, e. g. in a lower incidence of refractures.

[Serum cobalt and serum chromium level in 2 patients with chronic renal failure after total hip prosthesis implantation with metal-metal gliding contact]. / Serumcobalt- und Serumchromspiegel bei zwei chronisch niereninsuffizienten Patientinnen mit Hüfttotalendoprothese und Metall-Metall-Gleitpaarung.

PURPOSE: The influence of chronic renal failure on serum cobalt and serum chromium in two patients with metal-on-metal bearing (Metasul) and cementless total hip arthroplasty (Alloclassic) is investigated. METHODS: Serum cobalt and serum chronium levels were determined in the postoperative course using atomic absorption spectrometry. RESULTS: Maximum values are found to be more than 100-fold elevated when compared to the reported median serum cobalt concentrations in patients with the same prosthesis type and no known renal disease. CONCLUSION: Chronic renal failure seems to be responsible for the marked elevation of serum cobalt and serum chromium. CLINICAL RELEVANCE: Despite evidence of adverse health reactions, a possible effect of long-term cobalt and chromium loading cannot be neglected. In our opinion, metal-on-metal bearings in THA should not be inserted in patients with chronic renal failure. Follow-up investigations (serum cobalt, serum chromium, serum creatinine, BUN, echocardiography) should be performed at short intervals.

Serum antibodies against the heat shock protein 60 are elevated in patients with osteosarcoma.

Osteosarcoma is the most frequent malignant bone tumor, mainly occurring in the second and third decade of life. Diagnosis is limited to clinical symptoms, radiology and histology, but so far no diagnostic laboratory tests are available. Heat shock proteins (hsp), highly conserved proteins performing vital intracellular chaperoning functions and preventing cells from death, have been shown to be involved in tumor immunity. We analyzed 75 sera from 23 patients with high-grade osteosarcoma, 8 patients with chondrosarcoma, 10 patients with Ewing's sarcoma, 5 patients with soft tissue sarcoma, 11 patients with benign bone tumors at the time of diagnosis and from 18 healthy controls with an indirect one-site enzyme linked immunosorbent assay (ELISA) for the presence of anti-hsp60 and 70 antibodies. In these assays 10/23 osteosarcoma patients (43%) had anti-hsp60 antibodies with a mean +/- S.D. titer of 0.382 +/- 0.243 U/ml. Only one of the 18 healthy controls (1/18, 5.6%; titer 0.22 U/ml), two of the Ewing's sarcoma patients (2/10, 20%; titer 0.2 +/- 0.09 U/ml), two of the patients with a benign bone tumor (2/11, 18%; titer 0.22 +/- 0.16 U/ml) and one of the chondrosarcoma patients (1/8, 12.5%; titer 0.14 U/ml) were positive, whereas all others, including all soft tissue sarcomas were negative throughout. Anti-hsp60 antibodies in patients with osteosarcoma are therefore significantly increased (p < 0.05). 19/23 (83%) of osteosarcoma biopsy specimens expressed hsp60 immunohistochemically and all specimens from patients with a positive anti-hsp60 serum titer expressed hsp60. The level of the anti-hsp60 antibodies did not correlate with clinical parameters such as response to preoperative chemotherapy, duration of symptoms, age, gender, tumor size, serum alkaline-phosphatase levels and metastases. Although no difference in anti-hsp70 antibodies could be observed between sera from patients and healthy controls, a positive correlation was found for the presence of anti-hsp70 serum antibodies and lung metastases at the time of diagnosis in osteosarcoma patients. These data suggest an increase of anti-hsp60 antibodies at the time of first diagnosis of osteosarcoma. These findings should therefore give rise to further investigations on a group of new markers for the diagnosis of osteosarcoma.

Antibodies to heat shock protein 90 in osteosarcoma patients correlate with response to neoadjuvant chemotherapy.

Autoantibodies to the heat shock protein 90 (Hsp 90) have been reported as prognostic marker in breast cancer patients. Sera from 20 high-grade osteosarcoma patients were tested at the time of diagnosis by enzyme-linked immunosorbent assay. Presence of anti-Hsp90 antibodies correlated with a better response to neoadjuvant chemotherapy (P < 0.01), whereas the absence correlated with development of metastases. These data suggest that anti-Hsp90 antibodies might be of predictive value in human osteosarcoma.

Detection of orthopaedic prostheses at airport security checks.

We studied the detection of joint replacements at airport security checks in relation to their weight, using two types of detector arch. A single-source, unilateral detector showed different sensitivities for implants on different sides of a test subject. All implants weighing more than 145 g were detected by one of the arches. The degree of detection was directly related to the logarithm of the weight of the prosthesis in patients, with a linear correlation (r2 = 0.61). A bilateral arch detected all prostheses weighing over 195 g. With their usual sensitivity settings many joint replacements were detectable; an identification pass containing the site and weight of such prostheses would help to avoid the need for body-search procedures.

Contractile function of human veins after long-term storage in different media.

We wished to determine the preservation of contractile function of human saphenous veins during long-term storage (36 and 96 h) at low temperatures in different solutions. Two crystalloid solutions (Krebs-Henseleit and Bretschneider's cardioplegic solution), as well as heparinized blood and albumin solution as used in cardiac surgery were compared. Contractile function of human saphenous vein ring segments was tested in a vessel myograph. Potassium chloride (KCl 80 mM) was used to achieve receptor-independent maximal contraction; contractility to norepinephrine (NE) was tested in a concentration-dependent manner (10(-8)-10(-6)M). Nitroglycerin (NTG) was used to test vascular relaxation. Thirty-six hours of storage in 5% human albumin abolished responses to KCl and to NE. At this time, contraction of vein ring segments stored in heparinized blood was decreased to 24% in response to KCl and to 16% in response to NE. After 36-h storage in Bretschneider's cardioplegic solution, contractile function was not significantly decreased. The contraction was still 82% after KCl and was unchanged after NE. After 96 h, the contractile response was markedly impaired in all vein ring segments, and no relevant differences were evident between the solutions. In all experiments, NTG caused complete relaxation. Because Bretschneider's cardioplegic solution preserved vascular contractile function for 36 h, the implementation of this solution might enable long-term storage of human vessels for transplantation, bypass grafts, and in vitro experiments.

Simultaneous assessment of cardiac output with pulsed Doppler and electromagnetic flowmeters during cardiac stimulation.

The aim of this study was to test the accuracy of cardiac output assessment by Doppler and electromagnetic flowmetry in dogs during states of (1) marked enhancement in cardiac output, which was obtained by means of either isoprenaline infusion or treadmill exercise, or (2) reduction in cardiac output obtained by administration of phenylephrine. Additionally, in vitro comparisons were undertaken between Doppler and electromagnetic flow-probes and assessment of flow by direct volumetric measurement. These in vitro experiments showed a good correlation between timed volume collections and electromagnetic flow assessment up to high flow velocities. Doppler flow measurements underestimated the flow at high velocities. In both the resting dog and after phenylephrine, that is, at states with low heart rate and cardiac output, the waveforms of electromagnetic flow and Doppler velocity were similar for both phasic and mean flow, respectively. During states of cardiac stimulation Doppler flow showed a decrease in maximum velocity in the ascending aorta. Due to this decrease in peak flow velocity, mean Doppler blood flow did not increase despite of increased heart rate. This result cannot be explained on the basis of the deviation of Doppler measurements at high velocities in the in vitro experiments. Although our results are in contradiction with earlier studies, electromagnetic assessment seems to be more reliable in blood flow measurements in the ascending aorta. Hence, Doppler flow measurements should not be used uncritically for such quantitative flow assessment in large vessels as determination of cardiac output.

Influence of alpha 1-adrenoceptor blockade and/or 5-HT1A agonism on blood pressure and heart rate at rest and during exercise in hypertensive dogs.

1. Antihypertensive effects resulting from alpha 1-adrenoceptor blockade and stimulation of central nervous 5-HT1A receptors were compared with the effects arising from stimulation of 5-HT1A receptors alone during arterial hypertension. 2. Urapidil and 5-methyl-urapidil were less effective in decreasing arterial blood pressure than the lowest dose of the selective 5-HT1A receptor agonist, flesinoxan. After the higher dose of urapidil, a certain dampening of barareceptor reflex was found which was also seen with flesinoxan. 3. Flesinoxan was the only drug which did not reduce the exercise-induced increase in systolic arterial blood pressure. 4. Stimulation of 5-HT1A receptors alone, which is assumed to occur with flesinoxan, exerted antihypertensive activity only at low doses, without inducing reflex tachycardia at rest. 5. Only the combined effects of alpha 1-adrenoceptor blockade and 5-HT1A receptor stimulation, as assumed to occur with urapidil and 5-methyl-urapidil, lead to both a decrease in arterial blood pressure at rest and during exercise.

Oral N(G)-nitro-L-arginine in conscious dogs: 24 hour hypertensive response in relation to plasma levels.

Haemodynamic changes after oral administration of 30 mg/kg N(G)-nitro-L-arginine (L-NNA) were studied in conscious chronically instrumented mongrel dogs throughout a 24 h observation period in order to evaluate the long-term efficacy of L-NNA-induced inhibition of endothelium-dependent relaxation and its relation to plasma L-NNA level. Diastolic blood pressure remained elevated for the entire 24 h observation period, but systolic blood pressure was raised only up to the 6 h value. The hypertensive response was accompanied by bradycardia. The increase in blood pressure and the plasma L-NNA level both reached their maxima at 3 h. The plasma L-NNA level at the end of the observation period was diminished by only 21.7% with respect to the maximum increase, whilst the maximum increase in mean arterial blood pressure was attenuated by 72.2% at 24 h. These data show a dissociation between plasma L-NNA level and the respective blood pressure.

Cardiovascular and side effects of flesinoxan in conscious hypertensive dogs. Modulation by prazosin.

Previous studies on anaesthetized animals indicate that flesinoxan exerts hypotensive effects via stimulation of central 5-HT1A receptors. The purpose of the present study was to investigate the cardiovascular and side effects of flesinoxan in conscious, renal hypertensive dogs at rest and during exercise. Animals were pretreated with prazosin (2.5 or 7.5 nmol/kg) to verify a reduction of dose-dependent side effects, as occurred in normotensive dogs. A decrease in blood pressure without reflex tachycardia was observed only with the lower dose of flesinoxan (0.1 mumol/kg). The higher dose (0.2 mumol/kg) led to an increase in blood pressure and heart rate. The increase in heart rate during exercise was diminished by 0.2 mumol/kg flesinoxan. Pretreatment with prazosin resulted in an additive hypotensive effect at rest. Side effects, occurring primarily after the higher dose of flesinoxan, were not influenced by prazosin. It is concluded that flesinoxan is not likely to be efficacious in antihypertensive therapy.

Alpha 1-adrenoceptor blockade and/or 5-HT1A agonism during treadmill exercise in dogs.

1. The hypotensive effects of alpha 1-adrenergic blockade and/or stimulation of central nervous 5-HT1A receptors were studied using drugs with different affinity for central nervous 5-HT1A and peripheral alpha 1-adrenoceptors. Urapidil, 5-methylurapidil, flesinoxan and 8-OH-DPAT were compared under states of different activation of the autonomic nervous system, i.e. at rest and during graded treadmill exercise. 2. The rank order of hypotensive potency as derived from the most extensive decrease in resting diastolic arterial blood pressure was urapidil greater than 5-methylurapidil greater than flesinoxan much greater than 8-OH-DPAT. 3. The reflex increase in heart rate due to the decrease in arterial blood pressure at rest was suppressed after 0.1 mumol kg-1 flesinoxan. 4. The reflex increase in heart rate due to the decrease in arterial blood pressure at rest was less accentuated after high doses of urapidil and 5-methylurapidil. 5. During exercise both 5HT1A receptor agonists, flesinoxan and 8-OH-DPAT, decreased sympathetic tone. 6. The combined effects of alpha 1-adrenoceptor blockade and 5-HT1A receptor stimulation (urapidil and 5-methylurapidil) result in distinct decreases in blood pressure and slight suppression of reflex tachycardia at rest after high doses. Stimulation of 5-HT1A receptors alone (flesinoxan) suppresses reflex tachycardia by modulation of baroreceptor reflex and at high dose also diminishes exercise-induced increase in sympathetic tone.

[Cardiovascular pharmacology. An example of the need of clinically relevant pharmacological research]. / Herz- und Kreislaufpharmakologie. Ein Beispiel der Notwendigkeit kliniknaher pharmakologischer Forschung.

Like all other scientific disciplines, preclinical pharmacological research is subject to permanent changes. New measuring devices and the possibility of continuous on line data acquisition have markedly influenced basic research in this field. Another aim of modern cardiovascular pharmacology is the testing of promising drugs in clinically relevant animal models of disease, particularly under conditions, referring to the everyday situation in patients, e.g. physical activity. Investigations carried out in this way allow an exact assessment of the clinical efficacy of new drugs, and are, thus, clearly indispensable, also from the ethical point of view, before primary evaluation of the drug in man.

Esmolol: effects on isoprenaline- and exercise-induced cardiovascular stimulation in conscious dogs.

Esmolol, a recently developed ultra-short acting beta-adrenoceptor blocking agent, was evaluated in 12 conscious chronically instrumented dogs with intact autonomic reflexes. The significance of its beta 1-adrenoceptor selectivity was examined at various cardiovascular activation levels established by either incremental isoprenaline infusion or graded treadmill exercise. The observed parameters were heart rate, systolic and diastolic arterial blood pressure, left ventricular dp/dtmax, and left ventricular end-diastolic pressure. Intravenous infusion of esmolol (25 and 250 micrograms.kg-1.min-1) led to a dose-dependent reduction of the isoprenaline-induced increase in positive dp/dtmax. The concomitant increase in heart rate was suppressed to a lesser extent. Characteristically of a beta 1-selective agent, esmolol had only a slight effect on the isoprenaline-induced reduction in diastolic blood pressure. The impact of esmolol on exercise-induced hemodynamic activation was much smaller. Exercise-induced increase in positive dp/dtmax was more sensitive to beta-adrenoceptor blockade than the concomitant increase in heart rate. Diastolic blood pressure was not influenced significantly. beta-Adrenoceptor blockade was virtually reversed within 20 min of discontinuation of esmolol infusion.

Cardiac and hemodynamic effects of diltiazem during exercise-induced myocardial dysfunction in dogs.

The effects of diltiazem were tested in chronically instrumented dogs in a model of exercise-induced myocardial dysfunction. Since various bradycardiac agents have beneficial effects on myocardial function during ischemia, it was of interest to find out how a decrease in afterload, possibly combined with a decrease in myocardial oxygen demand, influences dysfunction. Therefore, diltiazem (1 mg/kg i.v.) was tested during critical stenosis of the circumflex branch of the left coronary artery, which led to exercise-induced myocardial dysfunction. At rest, diltiazem causes a reflex increase in heart rate. During exercise, a decrease in heart rate and hence in myocardial oxygen demand was neutralized by a decrease in arterial blood pressure and hence a lowered myocardial perfusion pressure. Therefore, systolic shortening in the ischemic area improved neither at rest nor during exercise after diltiazem.