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J Spicka

Publications and source records attributed to J Spicka.

15 recordsLinked to original sources
PubMed2005

[Surgical therapy of osteolysis around stable cementless hip arthroplasty].

PURPOSE OF THE STUDY: The article presents results of surgical treatment of osteolysis around stable cementless THA. MATERIAL AND METHODS: The authors evaluated 18 operated on cases of osteolysis around stable THA of ABG 1 type with a minimal follow-up of 4 years (49-70 months). The group included 6 men and 12 women who were at the time of revision 47 years old (36-56, SD 6.52). The average period between the primary and revision surgery was 45 months (23-66, SD 13.84), the average size of the original cup was 49.6 mm (44-54, SD 3.03), the median thickness of polyethylene was 7.5 mm (4.9-8.9). The average HHS prior to reoperation was 68.5 points (10-98, SD 18.3) and only three hips were completely asymptomatic (3/18, 17%). Polyethylene inlay was replaced twice, both acetabular components in twelve cases, the acetabular and femoral components in four cases. In 16 cases radical debridement and treatment of defects by bone grafting was an important part of surgery. OUTCOMES: By the time of the latest check, in total three revision surgeries were performed (3/18, 17%). Neither of them was necessitated by loosening of the revision cup or use of bone grafts. Revised were both hips after the replacement of polyethylene cup inlay. Stable bone fixation and healing of bone defect was achieved in 15 hips in which the implant replacement was combined with bone grafting (15/16, 94%). The revision cup was on average by 3.16 mm bigger than the original cup (p = 0.001). The average HHS during the latest check was 79 points (p = 0.056). DISCUSSION: In osteolysis around a stable implant, many North-American authors prefer the replacement of polyethylene cup inlay in case of an undamaged well-oriented metal cup with a functional lock. By contrast, the authors of this study in such indication replace the whole acetabular component. This discrepancy may be explained by the ABG 1 THA which often triggers an extensive osteolysis and fails relatively soon. CONCLUSION: Despite a small number of cases the study has proved that the bone bed damaged by osteolysis is able to accommodate a new cementless implant. A necessary part of the surgery is radical debridement and in more extensive defects also bone grafting.

Adult↗
PubMed2004

[Is osteolysis associated with a stable total hip replacement asymptomatic?].

PURPOSE OF THE STUDY: It has been reported that periprosthetic osteolysis in a stable cementless total hip prosthesis is often free from symptoms. The aim of this study is to check this assumption and provide details on the clinical presentation of this troublesome and worrying complication of hip arthroplasty. MATERIAL: Between March 1999 and June 2002, 76 hips in 72 patients underwent revision arthroplasty for periprosthetic osteolysis associated with stable ABG I prostheses. This patient group included 53 females and 19 males. The average age at the time of revision was 49 years (range, 32 to 63). The average time between the primary and revision surgery was 54.6 months (range, 23 to 85). The average cup size was 49.7 mm (range, 44 to 60), the modular 28-mm CoCr head was used in 69 hips, 28-mm ceramic head in six hips, and 22-mm CoCr head in one patient. METHODS: The following characteristics were recorded: gender, age, type of patient, height, weight, symptoms, diagnosis, ERS, CRP, Harris hip score, cup size, abduction angle and extent of bony defects. The data of symptomatic and asymptomatic patients were compared by parametric or non-parametric tests. RESULTS: Before revision, 61 hips (80%) were symptomatic. The patients complained of pain or signs of instability or both, and these complaints were taken as indications for revision surgery. The remaining 15 hips (20%) were asymptomatic. The average period from the primary surgery to the appearance of the first symptoms was 43 months (range, 5 to 80). The average Harris hip score before revision was 68 points (range, 37 to 90) and 82 points (range, 10 to 98) in the symptomatic and asymptomatic patients, respectively (p = 0.002). There were no other significant differences between these patients. DISCUSSION: The results of our study are in agreement with the findings of Hozack et al., but not with those of Maloney et al. and others who have reported that the progression of osteolysis developing in association with hip arthroplasty can be without symptoms. CONCLUSIONS: Osteolysis developing around a stable cementless hip prosthesis is generally symptomatic, with pain being the most frequent symptom. Even without a periprosthetic fracture, osteolysis may seriously impair the function of a joint and comfort of the patient. Since symptomatic patients are likely to see their attending physicians, it is emphasized that attention should also be paid to asymptomatic patients who have prostheses with unsuitable designs or pairings.

Adult↗
PubMed2004

[Validity of bone scintigraphy for the diagnosis of periprosthetic complications in hydroxyapatite-coated total hip arthroplasty].

PURPOSE OF THE STUDY: To evaluate the efficacy and usefulness of 99Tc-MDP bone scans for the diagnosis of complications associated with hydroxyapatite- coated total hip prostheses. MATERIAL AND METHODS: 99Tc-MDP bone scans of 42 hips were taken before revision surgery in 41 patients with ABG 1 prostheses. Of these, 26 patients (27 hips) were included in our study on the basis of the following criteria: at least 23 months between the index surgery and scintigraphic examination and the availability of good quality bone scans. The average patients' age at the time of index and revision operations was 45.3 years (range, 32-57; SD, 6.02) and 50.2 years (36-61; SD, 6.01), respectively. The average time between the index surgery and bone scintigraphy was 50.3 months (23-84; SD, 15.9). Two experienced specialists in nuclear medicine, who were unaware of any clinical conclusions, participated in the study. RESULTS: Pre- and intra-operative findings showed aseptic loosening in three cups (3/27, 11 %) and one stem (1/27, 4 %). Four hips were suspected to have an infection on the basis of the positive results of intra-operative culture. In the diagnosis of aseptic loosening, sensitivity, specificity, accuracy, and positive and negative predictive values of bone scintigraphy were 100 %, 57 %, 62 %, 23 %, and 100 %, respectively, for the ABG I cup and 100 %, 52 %, 54 %, 8 %, and 100 %, respectively, for the ABG I stem. These characteristics were 67 %, 96 %, 93 %, 67 %, and 96 %, respectively, for the ABG I cup, when plain X-ray was used for evaluation of aseptic loosening. Specificity, accuracy and negative predictive value of plain X-ray for ABG I stem aseptic loosening were 100 %, 96 %, and 96 %. Bone scintigraphy gave one false positive result of sepsis; on the other hand, none of the four hips with positive intraoperative culture was diagnosed as septic. DISCUSSION: The fact that 99Tc-MDP bone scintigraphy as a method of diagnosing periprosthetic complications has a high sensitivity and a relatively low specificity has often been discussed in the literature. Currently, there are only a few studies on bone scintigraphy investigations of hydroxyapatite-coated prostheses. Some authors report that a slight increase in peri-prosthetic radionuclide activity may persist for up to 8 years which can explain the problematic accuracy of the technique. CONCLUSIONS: 99Tc-MDP bone scintigraphy is an intermediate useful tool for detecting complications of total hip arthroplasty with hydroxyapatite- coating. A negative bone scan almost always suggested the absence of aseptic loosening. However, the value of a positive result was regarded as controversial for the diagnosis of both aseptic and septic complications.

Adult↗
PubMed2001

Interaction between two adapter proteins, PAG and EBP50: a possible link between membrane rafts and actin cytoskeleton.

Phosphoprotein associated with GEMs (PAG), also known as Csk-binding protein (Cbp), is a broadly expressed palmitoylated transmembrane adapter protein found in membrane rafts, also called GEMs (glycosphingolipid-enriched membrane microdomains). PAG is known to bind and activate the essential regulator of Src-family kinases, cytoplasmic protein tyrosine kinase Csk. In the present study we used the yeast 2-hybrid system to search for additional proteins which might bind to PAG. We have identified the abundant cytoplasmic adapter protein EBP50 (ezrin/radixin/moesin (ERM)-binding phosphoprotein of 50 kDa), also known as NHERF (Na(+)/H(+) exchanger regulatory factor), as a specific PAG-binding partner. The interaction involves the C-terminal sequence (TRL) of PAG and N-terminal PDZ domain(s) of EBP50. As EBP50 is known to interact via its C-terminal domain with the ERM-family proteins, which in turn bind to actin cytoskeleton, the PAG-EBP50 interaction may be important for connecting membrane rafts to the actin cytoskeleton.

Actins↗
PubMed2001

Structural and functional dissection of the cytoplasmic domain of the transmembrane adaptor protein SIT (SHP2-interacting transmembrane adaptor protein).

SIT (SHP2-interacting transmembrane adaptor protein) is a recently identified transmembrane adaptor protein, which is expressed in lymphocytes. Its structural properties, in particular the presence of five potential tyrosine phosphorylation sites, suggest involvement of SIT in TCR-mediated recruitment of SH2 domain-containing intracellular signaling molecules to the plasma membrane. Indeed, it has recently been demonstrated that SIT inducibly interacts with the SH2-containing protein tyrosine phosphatase 2 (SHP2) via an immunoreceptor tyrosine-based inhibition motif (ITIM). Moreover, SIT is capable to inhibit TCR-mediated signals proximal of activation of protein kinase C. However, inhibition of T cell activation by SIT occurs independently of SHP2 binding. The present study was performed to further characterize the molecular interaction between SIT and intracellular effector molecules and to identify the protein(s) mediating its inhibitory function. We demonstrate that SIT not only interacts with SHP2 but also with the adaptor protein Grb2 via two consensus YxN motifs. However, mutation of both Grb2-binding sites also does not influence the inhibitory function of SIT. In contrast, mutation of the tyrosine-based signaling motif Y(168) ASV completely abrogates the ability of SIT to inhibit T cell activation. Co-precipitation experiments revealed that the tyrosine kinase p50(csk) could represent the negative regulatory effector molecule that binds to this motif.

Adaptor Proteins, Signal Transducing↗
PubMed1988

Separating output factor into collimator factor and phantom scatter factor for megavoltage photon calculations.

Output factor has been used in megavoltage dosage calculations because collimator factor and backscatter factor are considered individually indeterminable. Output factor reflects the normalized product of backscatter factor and collimator factor for the most common treatment geometry. A method has been found for independently measuring collimator factors for megavoltage photons. Using a build-up cap of high density tissue equivalent material, we have measured the relative collimator factors for various units with photon energies up to 15 MV. Utilizing measured values for output factor and collimator factor relative backscatter factors have been determined.

Humans↗
PubMed1988

Polyethylene-lead tissue compensators for megavoltage radiotherapy.

Tissue compensators afford one the opportunity of producing idealized dose distributions in radiotherapy. We have developed a technique which may be used to produce fast, accurate and inexpensive compensators within a few minutes and requires minimal patient involvement. Three dimensional contour data is acquired using a moire fringe photograph taken at the time of simulation. The photograph is projected to the size needed for the actual compensator and a sketch of the compensator is made. The sketch is placed in a specially designed small portable pantographic unit and the design is traced while the unit cuts the compensator from an indexed polyethylene-lead blank which is premounted on an acrylic tray. The polyethylene-lead material proves to have an ideal combination of properties for compensator construction including relatively high density, ease of machining, good handling characteristics and low cost.

Humans↗
PubMed1975

[Transient infarct-like ECG findings in cholecystectomy].

It is reported on the appearance of transient infarction-like electrocardiographic changes in a 49-year-old female patient which developed during a cholecystectomy after cardiac arrest due to a considerable loss of blood. The ECG normalised within 7 minutes, neither accompained nor followed by any pathologic ion displacements in the systemic blood or by enzyme changes (GOT, GPT).

Cholecystectomy↗