Zoltán Csernátony

A purinergic signal transduction pathway in mammalian skeletal muscle cells in culture

Abstract. The effects of adenosine 5′-triphosphate (ATP) on human and mouse skeletal muscle fibres in primary culture were investigated. ATP-evoked changes in intracellular calcium concentration ([Ca2+]i) were measured and compared with those induced by agonists of the nicotinic acetylcholine (Ach)- and P2X purinoreceptors. While ATP was effective on both myoblasts and multi-nucleated myotubes in the micromolar range, Ach failed to induce any change in [Ca2+]i at early stages of development. In contrast, myofibres with peripheral nuclei showed little response to ATP but responded to Ach with a large change in [Ca2+]i. The responsiveness of the myotubes to Ach paralleled that to potassium. The removal of external calcium abolished the response to ATP. P2X receptor agonists mimicked the response to ATP with the order of potency being ATP>2′,3′-O-(4-benzoyl)-benzoyl-ATP>β,γ-methylene-ATP>α,β-methylene-ATP. Under voltage-clamp conditions ATP induced an inward current that showed little inactivation. These results are consistent with the existence of P2X receptor-mediated signal transduction pathway in cultured mammalian skeletal muscle cells.

Ex vivo and in vitro determination of the axial rotational axis of the human thoracic spine.

Study Design. Different geometrical and biomechanical evaluations were performed to determine the axial rotational axis of the thoracic spine. Objective. Our research group has been dealing with the determination of the axial rotational axis of the thoracic spine. Here, we would like to present the geometrical and experimental results of our trials. With our experiments, we are trying to evaluate the contradictions of the related literature. Summary of Background Data. In the present state, we know quite a lot about the biomechanics of healthy and pathologic spines. Nevertheless, for a seemingly simple question like the position of the axial rotation of the thoracic spine, the literature gives contradicting results. During correction of a scoliotic deformity, when trying to correct the pathologic rotation, not knowing the physiologic rotation can be hazardous. Methods. We wanted to clarify this question, so we examined the thoracic spine in many different ways. First, we examined the problem from a geometrical point of view then we modeled the different rotational axes by studying the change in volume of the spinal canal. Finally, we used cadaver spines that we rotated and examined with radiographs and digital pictures. Results. Based on the results, we made the following establishments: most of the center points fell on the anterior half of the vertebral body or into the spinal canal, basically on the midsagittal axis of the vertebra. The rib cage has a significant effect on the place of the axis. After removing the ribs, the axis of axial rotation moved forward. Conclusions. After evaluating the results, we determined that the most likely place for the rotational axis is on the median-sagittal plane, in the anterior portion of the spinal canal.

The most severe forms of Perthes' disease associated with the homozygous Factor V Leiden mutation

It has recently been postulated that thrombophilia may have a role in the aetiology of Perthes disease. The published reports, however, remain conflicting. In this study a retrospective analysis of the coagulation parameters was made in 47 patients with Perthes disease and the results compared with the clinical data. Five patients with Factor V Leiden mutation were found (10.6%) and surprisingly four of them had a homozygous pattern. These four patients showed the most severe form of the disease, Catterall group IV, with flattening of the entire epiphysis, involvement of the metaphysis, shortening and broadening of the femoral neck, trochanteric overgrowth and developed mushroom-shaped aspherical laterally displaced femoral heads in dysplastic acetabula. We would like to suggest that the homozygous form of Factor V Leiden mutation has some role in the clinical course of Perthes disease and particularly its most severe form.

Thrombotic and fibrinolytic alterations in the aseptic necrosis of femoral head

&NA; Recent reports seem to support the role of the thrombophilia and decreased fibrinolysis in the aetiopathogenesis of aseptic necrosis of bone. In the present study, haemostatic disturbances were analysed in adults (n = 49) and patients in childhood (Perthes disease) (n = 47) with aseptic necrosis of the femoral head. Fibrinolytic parameters (in vitro clot lysis, plasminogen, plasmatic plasminogen activator inhibitor‐1 activity, D‐dimer) along with lipoprotein (a) [Lp(a)] and fibrinogen were measured. von Willebrand factor, platelet activation and some thrombophilic factors (activated protein C resistance and factor V Leiden mutation, protein C, protein S activity) were also determined. Impaired fibrinolysis, an increased Lp(a) level along with slow clot lysis and increased platelet activation were found in adult cases. We detected five cases of factor V Leiden mutations (one heterozygotic and four homozygotic) among patients with Perthes disease. The clinical course of the heterozygous case was similar to the usual form of Perthes disease. The most severe form of Perthes disease has been observed in homozygous factor V Leiden mutation cases. The mutation of factor V Leiden per se probably does not induce the development of aseptic necrosis of bone tissue in childhood, but it does play a role in its acceleration. Homozygous factor V Leiden mutation definitely runs a more severe course. On the other hand, in adult cases, the disturbances of haemostasis, impaired fibrinolysis, elevated Lp(a) level, increased platelet activation and slight elevation of fibrinogen might have clinical relevance. Further studies should focus on proving the role of the haemostatic alterations in the pathogenesis of severe forms of aseptic bone necrosis. The use of antithrombotic drugs in order to slow the process of aseptic necrosis also has to be addressed in future surveys. Blood Coagul Fibrinolysis 14:243‐248

Histological changes in the symptomatic mediopatellar plica

One of the causes of anterior knee pain may be symptomatic mediopatellar plica. The pain is usually attributed to the mechanical damage caused by the plica inside the joint, or, more precisely, to the synovitis induced as a result. Recent observations seem to suggest, however, that the pain is, in addition, likely to be engendered by an increased number of nerve-elements present in the substance of the plica. The present study used up-to-date histochemical methods to reveal in the symptomatic mediopatellar plicae nerve-elements that may be made responsible for the pain. Semi-quantitative methods were used to establish the number of nerve-elements in the tissue samples obtained from 21 symptomatic mediopatellar plicae (Group A), exposing them to view with the aid of synaptophysin and neurofilament serum, coupled with routine light microscope as well as polarising microscope examinations following H&E and van Gieson staining. Tissue samples taken from the asymptomatic mediopatellar plica of 11 patients served as control (Group B). A significantly larger number of nerve-elements were found in the substance of the plicae of Group A 6.9 (S.D.+/-2.9) than in Group B 3 (S.D.+/-1.2). Within Group A, more nerve-elements were revealed in trauma-related case histories than in those with no recollections of trauma (an average of 9.6 vs. 5.2, respectively). Similarly, the reduction of pain achieved by surgery was greater in the trauma-related group than in the non-traumatic one (3.0 vs. 1.8, respectively). Relying on our observations, we claim that the painfulness of the knee joint plicae is in all probability also attributable to the fact that their tissue substance contains an increased number of nerve-elements. A major trauma in a particular case history contributes, in all likelihood, to an increase in the number of nerve-elements, but further examinations are required to clarify the pathomechanism involved.

Technique of synovial biopsy of metacarpophalangeal joints using the needle arthroscope

We demonstrate the technique, advantages, and disadvantages of metacarpophalangeal joint examination with needle arthroscope. We evaluated our experience from biopsies of 10 metacarpophalangeal joints of eight rheumatoid women aged 41–45xa0years. The procedures were performed using a 1-mm needle arthroscope. The synovium biopsy was taken with a microforceps. The procedure was performed under local anesthesia. The tight tension of the joint and traction of the finger is necessary for good visualization, but despite this visibility can be difficult. Needle biopsy is a useful method for the early diagnosis of rheumatoid arthritis.

Coccygectomy has a favorable effect on the intensity, manifestation, and characteristics of pain caused by coccygodynia: a retrospective evaluation of 34 patients followed for 3–18 years

BackgroundCoccygodynia can cause severe pain and disability in patients. There are contradictions in the literature regarding the final results of coccygectomy for coccygodynia. We evaluated the long-term effects of coccygectomy on the intensity, characteristics, and manifestation of pain caused by coccygodynia to determine the adequacy of operation among treatment modalities.Materials and methodsThirty-four patients with coccygodynia were treated by coccygectomy. In 22 cases, trauma, and in one case childbirth was the cause. 11 cases were regarded as idiopathic. The intensity, characteristics of pain, and the most painful activities were evaluated at an average of 7.6 (3–18) years of follow-up time.ResultsBefore the operation, all 34 patients had pain while sitting, moreover, 26 of them had pain during standing, walking, at night or a combination of these. 21 patients had intolerable or very intensive, mainly acute, sharp or burning pain. 11 patients had dyschesia, 2 had dysuria and 6 had dyspareunia. At follow-up, 7 patients were completely free of pain, 15 others had moderate, 11 medium, and only one patient had severe, but none had intolerable pain. Only seven patients had acute, sharp or burning pain postoperatively. The decrease of average pain score from 8.0 to 3.2 was significant (Pxa0<xa010−12). The number of the patients with dyschesia and dyspareunia decreased from 11 to 7 and from 6 to 3, respectively. Two patients had dysuria, but their complaints did not change after the operation. One of the two patients who needed reoperation had an excellent final result, while the other remained unchanged. 12 and 16 patients (together 82%) regarded the final result of the operation excellent and good, respectively. The condition of five others did not change, while one became worse. The patients with younger age, smaller body mass index, and less co-morbidities had better final result. There were no serious complications.ConclusionCoccygectomy for coccygodynia is a safe method to decrease the intensity of pain and other complaints of the patients. The operation can be the choice of treatment if conservative measures fail.

Biomechanical comparison of two stabilization techniques for unstable sacral fractures

AimThe purpose of the study was to assess the stability provided by an ilio-iliac dorsal plate fixation technique using an AO narrow DCP on the pelvic brim in vertically and rotationally unstable type-C pelvic ring injuries.Materials and methodsWe examined 12 fresh cadaver pelvises in a single limb stance load. A type-C pelvic ring injury (a type I lateral sacral fracture in the classification of Denis with symphysis pubis rupture) was performed on the cadaver specimen and fixed with a four-hole narrow dynamic compression plate to stabilize the symphysis pubis rupture; the sacrum fracture was stabilized either anteriorly with two 3-hole reconstruction plates (“anterior plate osteosynthesis”) or with a posterior fixation using a 12-hole narrow DCP. A cyclic load of between 100 and 250xa0N was applied to the fifth lumbar vertebra of the specimen. An extensometer was attached to both sides of the sacrum fracture to detect movements at the fracture site.ResultsWe were able to achieve usable measurements in nine specimens. Three measurements were performed on each specimen, and the movements recorded at the fracture gap in trans-sacral plate fixation were higher than or similar to those observed for anterior plate synthesis in 23 out of 27 cases.ConclusionDorsal ilio-iliac bridge plate fixation provides somewhat reduced stability compared to anterior plate fixation, but the difference is not significant.

Biomechanical examination of the thoracic spine—the axial rotation moment and vertical loading capacity of the transverse process

Our objective was to examine the load‐bearing capacity of the transverse processes of human cadaveric thoracic vertebrae to vertical loads and axial rotation moments (i.e., moment applied in the transverse plane). A secondary objective was to examine the effect of the attached rib stumps. We wanted to demonstrate that the transverse process is durable enough to support the CAB hook—a complementary hook to the CD system—and can handle the vertical load or axial rotation moment during correction of scoliosis. We used 107 thoracic vertebrae removed from 10 cadavers. They were prepared in vertebral pairs, and were fixed into a material testing apparatus. Superoinferior vertical loads and axial rotation moments were applied to the transverse process using the CAB hooks at a rate of 30u2009mm/min and 8.5°/s respectively until it fractured. We recorded 142 measurements, 99 were for vertical load and 43 for axial rotation moment. The average ultimate vertical load was 338 (SDu2009=u2009128) N and the average ultimate axial rotation moment was 14.4 (SDu2009=u20094.52) Nm. The ultimate axial rotation moment for specimens with rib stumps attached was significantly greater than for specimens without rib stumps 15.9 (SDu2009=u20094.1) Nm versus 12.5 (SDu2009=u20094.4) Nm. Our results showed that both the vertical and axial rotation loading capability of the transverse process are large enough to withstand significant correctional forces, without fracture, through the CAB hooks.

Retrograde stem removal in revision hip surgery: removing a loose or broken femoral component with a retrograde nail

IntroductionRemoval of a cemented femoral stem during revision total hip arthroplasty is a technically demanding procedure that requires a multitude of surgical techniques and tools. To gain full access to the cement and the stem, distal fenestration or a transfemoral approach is often required. This paper presents a technique of retrograde removal of femoral stems and cement from the distal femur.Materials and methodsThe authors present five clinical cases. In two cases the femoral component and the surrounding cement was removed using this technique. In the other three cases, due to femoral component fracture, the distal fragment of the femoral component with its cement mantle was removed using the same technique. In an experimental study, we simulated the above technique and compared it with a windowing technique on six, paired cadaveric femora (12 femurs in all).ResultsIn all of the clinical cases the stem and the cement were removed completely without any complications. The cadaveric experiments clearly showed that the biomechanical resistance of the femur against compression and torsion forces is greatly decreased by using a window to access the proximal femur, compared with the retrograde technique, which shows no significant change.ConclusionRetrograde component removal provides a simple, rapid, and less invasive technique for stem and cement extraction in elective revision hip arthroplasty.