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101.
102.
Percutaneous vertebroplasty, comprising an injection of polymethylmethacrylate (PMMA) into vertebral bodies, is a practical procedure for the stabilization of osteoporotic compression fractures as well as other weakening lesions. Cement leakage is considered to be one of the major and most severe complications during percutaneous vertebroplasty. The viscosity of the material plays a key role in this context. In order to enhance the safety for the patient, a rheometer system was developed to measure the cement viscosity intraoperatively. For this development, it is of great importance to know the proper viscosity to start the procedure determined by experienced surgeons and the relation between the time period when different injection devices are used and the cement viscosity. The purpose of the study was to investigate the viscosity ranges for different injection systems during conventional vertebroplasty. Clinically observed viscosity values and related time periods showed high scattering. In order to get a better understanding of the clinical observations, cement viscosity during hardening at different ambient temperatures and by simulation of the body temperature was investigated in vitro. It could be concluded, that the direct viscosity assessment with a rheometer during vertebroplasty can help clinicians to define a lower threshold viscosity and thereby decrease the risk of leakage and make adjustments to their injection technique in real time. Secondly, the acceleration in hardening of PMMA-based cements at body temperature can be useful in minimizing leakages by addressing them with a short injection break.  相似文献   
103.
Inhibition of proximal tubular phosphate (Pi) reabsorption involves, as far as we know, brush border membrane retrieval of the type IIa Na/Pi-cotransporter. The aim of the present study was to analyze whether intracellular cGMP-mediated regulation of Pi reabsorption also involves retrieval of the type IIa Na/Pi-cotransporter, as previously shown for cAMP. Atrial natriuretic peptide (ANP) and nitric oxide (NO) were used to stimulate guanylate cyclase. In vivo perfusion of mice kidneys with either ANP or NO donors resulted in a downregulation of type IIa Na/Pi-cotransporters on the brush border membranes of proximal tubules. These effects were mimicked by activation of protein kinase G with 8Br-cGMP. In in-vitro-perfused mice proximal tubules, ANP was effective when added either to the apical or basolateral perfusate, suggesting the presence of receptors on both membrane sites. The effects of ANP and NO were blocked by the protein kinase G inhibitor LY 83553. Parallel experiments in OK cells, a renal proximal tubule model, provided similar information. Our findings document that cGMP-mediated regulation (ANP and NO) of type IIa Na/Pi-cotransporters also takes place via internalization of the transporter protein.  相似文献   
104.
Kyphoplasty for treatment of osteoporotic vertebral fractures   总被引:15,自引:3,他引:12  
Cement reinforcement for the treatment of osteoporotic vertebral fractures is efficient mean with high success in pain release and prevention of further sintering of the reinforced vertebrae; however, the technique does not allow to address the kyphotic deformity. Kyphoplasty was designed to address the kyphotic deformity and help to realign the spine. It involves the percutaneous placement of an inflatable bone tamp into a vertebral body. Restoration of VB height and kyphosis correction is achieved by inflation of the bone tamp with liquid. After deflation, a cavity is created that eases the cement application. The potential of kyphosis reduction is given in fresh fractures with a range of 0–90% for height restoration and absolute correction of the kyphotic angle of 8.5°. The cavity formation, on one hand, and the different cementing technique leads to lower risk for cement extravasation. An alternative method for kyphosis correction represents the so-called lordoplasty where the adjacent vertebrae are reinforced first and with the cannulas in place acting as a lever the reduction of the collapsed vertebra can be performed. The results with respect to kyphosis correction are superior in comparison with a kyphoplasty procedure.  相似文献   
105.
Vertebroplastik bei hochgradiger Osteoporose   总被引:3,自引:0,他引:3  
Heini PF  Orler R 《Der Orthop?de》2004,33(1):22-30
Zusammenfassung Bei schwerer Osteoporose ist der progressive Kollaps mehrerer Wirbelkörper mit konsekutivem Haltungsverlust ein ungelöstes Problem. Die medikamentöse Therapie greift zu langsam, um diesen Verlauf aufzuhalten. Die zunehmende Erfahrung mit der Vertebroplastik hat dazu geführt, bei hochgradiger Osteoporose die mehrsegmentale Zementierungen durchzuführen. Von 362 Patienten, die im Verlauf der letzten 5 Jahre mit perkutaner Zement Injektion behandelt wurden, sind bei 100 Patienten 5 oder mehr Höhen augmentiert worden (Range=7,3; maximal 14,0). Die operative Technik wurde dahingehend verfeinert, dass problemlos 6 Niveaus monolateral in Lokalanästhesie verstärkt werden können. Pro Eingriff sollte diese Anzahl nicht überschritten bzw. nicht mehr als 25–30 ml Zement appliziert werden.Die Ergebnisse sind ermutigend. In 84% der Patienten konnte ein ausgeprägtes Schmerzsyndrom reduziert werden (von 7,6 nach 2,7 VAS). Noch eindrücklicher ist die subjektive Angabe der Patienten, die eine bessere Körperhaltung und mehr Kraft in ihrem Rücken beobachten und dadurch ihr Leben wieder aktiver gestalten können. Die radiologische Nachuntersuchung über 1 Jahr zeigt einen stationären Verlauf ohne weitere Sinterung der augmentierten Wirbel und einen erhaltenen Zwischenwirbelraum. Multisegmentale Vertebroplastik ist effizient und kann das weitere Zusammensintern und damit den Haltungsverlust verhindern. Aufgrund des Risikos der Fettembolie sollte die Augmentation auf 6 Höhen pro Eingriff beschränkt bleiben.  相似文献   
106.
OBJECTIVE: The overall prognosis of ovarian carcinoma is poor. However, the outcome of apparently similar cases is highly variable, and molecular markers that would predict disease outcome in a clinically useful manner are lacking. We investigated the value of p53 expression as a disease determinant in serous carcinoma, which is the most common type of ovarian carcinoma and has shown the highest frequency of p53 alterations. METHODS: Tissue microarray constructed of 522 serous ovarian carcinomas was examined immunohistochemically using DO-7 monoclonal antibody against p53 protein. The findings were correlated with overall and disease-free survival, response to therapy, and clinicopathological characteristics of the patients. RESULTS: Both excessive and completely negative p53 staining confered poor patient outcome and were considered aberrant p53 expression. Patients with aberrant p53 (59% of the carcinomas) showed 5-year overall survival of 26% (20-31%), whereas patients with normal p53 expression (41% of the carcinomas) showed 5-year overall survival of 79% (95% CI, 74-85%) (P < 0.0001). The association of aberrant p53 with poor prognosis was independent of clinicopathological parameters, e.g., stage and grade. In addition, aberrant p53 status was significantly associated with shorter disease-free survival (P < 0.0001) and poor response to therapy (P < 0.0001). In the most common subgroups, stage III and stage I carcinomas, 5-year overall survival rates for patients showing normal p53 vs. aberrant p53 were 72% vs. 19% (P < 0.0001) and 99% vs. 56% (P < 0.0001), respectively. CONCLUSION: P53 expression status divides serous ovarian carcinomas into two distinct subtypes: one with a relatively good prognosis and the other with a particularly poor outcome.  相似文献   
107.
The proximal tubular brush border membrane type IIa Na/P(i)-cotransporter is an important element in overall phosphate (Pi) homeostasis. Its regulation is tightly associated with membrane retrieval/reinsertion mechanisms. Specific molecular domains are involved in its internalization (predicted third intracellular loop) and in its apical expression (carboxy-terminus). Regulation and apical expression require a correct ('proximal tubular') cellular context and interaction with specific cellular proteins (scaffolding). Basic cotransport function is via a 3 Na+ to 1 P(i)-coupling ratio, also including the possibility of a Na+-leak, and is strongly affected by changes in pH. This function can be assigned to monomeric transporter molecules. The predicted first intracellular and third extracellular loops contribute important functional characteristics. It is suggested that they may form "re-entrant loops" and thereby a "permeation pore." Sequences in this region determine also pH-sensitivity and affinities in P(i)- and in Na+-interaction, respectively.  相似文献   
108.
Cultured renal epithelial cells grown on filter support were examined for functional adaptation of Na+/H+ exchange activities to respiratory acidaemia, which was mimicked by increasing PCO2 from 5% to 10% during 24 h or 48 h of cell culture. We have selected proximal tubular cell lines with either dual location of Na+/H+ exchange activities (MCT cells, RKPC-2 cells), apical location of Na+/H+ exchange activity (OK/ WOK cells) or a basolateral location of Na+/H+ exchange activities (LLC-PK1/clone 4 cells, MDCK cells). Na+/H+ exchange activity was determined microspectrofluorometrically (using BCECF) in the absence of CO2/HCO 3 . Respiratory acidaemia specifically increased apical Na+/H+ exchange activity (previously classified as amiloride-resistant) in MCT cells, in RKPC-2 cells and in WOK cells; it stimulated basolateral Na+/H+ exchange activity (previously shown to be amiloride-sensitive) in RKPC-2 cells, in LLC-PK1/clone 4 cells and in MDCK cells, but did not affect basolateral Na+/H+ exchange activity in MCT cells. In MCT and in RKPC-2 cells the effect of high PCO2 on apical Na+/H+ exchange was prevented by inhibition of protein kinase C. In RKPC-2 cells, activation of basolateral Na+/H+ exchange by high PCO2 occurred also when protein kinase C was inhibited. In conclusion, these studies demonstrate stimulation of apical Na+/H+ exchange, but differential regulation of basolateral Na+/H+ exchange activities in response to a high-PCO2-induced acid environment. Protein kinase C activation might be involved in mediating the effect of acidaemia on stimulation of apical Na+/H+ exchange activity (MCT and RKPC-2 cells).  相似文献   
109.
Extracellular phosphate concentrations are maintained by coordinated regulation of specific homeostatic mechanisms. A novel gene, the type IIb sodium-phosphate cotransporter (Npt2b), was recently cloned and is expressed within intestinal tissues, indicating that the transporter may be an important regulator of phosphate reabsorption. Another gene, human stanniocalcin-2 (STC2), was previously shown to decrease phosphate uptake into kidney cells in vitro. Because of the important role that STC2 may play in phosphate homeostasis, we considered the peptide hormone a candidate for the phosphate wasting disease autosomal dominant hypophos-phatemic rickets (ADHR), previously localized to chromosome 12p13. The purpose of our study was to determine the chromosomal localization of human NPT2b and STC2. In the present work, NPT2b was localized to human chromosome 4pl5-pl6, and STC2 to 5q33-tel. Because STC2 did not map to 12p13, the hormone was excluded as the ADHR gene, however it should be considered a candidate for other diseases involving phosphate homeostasis.  相似文献   
110.
Injection of messenger ribonucleic acid (mRNA) isolated from 1, 25-dihydroxyvitamin D3-treated osteoblast-like (PyMS) cells leads to an enhanced sodium-dependent phosphate (NadPi) transport in Xenopus laevis oocytes, when compared to untreated cells. After mRNA size fractionation, mRNA with an average size of 2.2–3.8 kilobases showed up to a 1.8-fold stimulation of NadPi transport encoding either directly a NadPi transporter(s) or proteins controlling their activity. No hybridization was observed in Northern blots with RNA from rat bone or PyMS cells with the recently cloned rat renal brush border NadPi transporter NaPi-2; hybrid depletion with a NaPi-2 antisense oligonucleotide did not abolish the PyMS mRNA-induced NadPi transport in oocytes. We present the first evidence for functional expression in Xenopus laevis oocytes of a new type of NadPi transport system in bone cells, which is different from the renal type.  相似文献   
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