Mortality and causes of death in systemic lupus erythematosus.

Cohort studies of survival in systemic lupus erythematosus (SLE) often have been limited by methodologic problems. In studies of inception cohorts of patients followed since 1980, survival at 5 years has exceeded 90%. These estimates are generally higher than survival estimates from earlier studies, suggesting that short-term survival in SLE has improved. There is less evidence to support major improvements over time in survival after 10 years or more of SLE. Infections, atherosclerotic disease, and active systemic lupus erythematosus or organ damage caused by SLE are the main causes of death in patients with SLE, but the proportion of early deaths caused by active SLE has decreased over time.

Functional requirement of p23 and Hsp90 in telomerase complexes.

Most normal human diploid cells have no detectable telomerase; however, expression of the catalytic subunit of telomerase is sufficient to induce telomerase activity and, in many cases, will bypass normal senescence. We and others have previously demonstrated in vitro assembly of active telomerase by combining the purified RNA component with the reverse transcriptase catalytic component synthesized in rabbit reticulocyte extract. Here we show that assembly of active telomerase from in vitro-synthesized components requires the contribution of proteins present in reticulocyte extracts. We have identified the molecular chaperones p23 and Hsp90 as proteins that bind to the catalytic subunit of telomerase. Blockade of this interaction inhibits assembly of active telomerase in vitro. Also, a significant fraction of active telomerase from cell extracts is associated with p23 and Hsp90. Consistent with in vitro results, inhibition of Hsp90 function in cells blocks assembly of active telomerase. To our knowledge, p23 and Hsp90 are the first telomerase-associated proteins demonstrated to contribute to telomerase activity.

Effects of extremely low frequency electromagnetic field (EMF) on collagen type I mRNA expression and extracellular matrix synthesis of human osteoblastic cells.

Human osteoblastic cells were grown in a three-dimensional (3-D) cell culture model and used to test the effects of a 20 Hz sinusoidal electromagnetic field (EMF; 6 mT and 113 mV/cm max) on collagen type I mRNA expression and extracellular matrix formation in comparison with the effects of growth factors. The cells were isolated from trabecular bone of a healthy individual (HO-197) and from a patient presenting with myositis ossificans (MO-192) and grown in a collagenous sponge-like substrate. Maximal enhancement of collagen type I expression after EMF treatment was 3.7-fold in HO-197 cells and 5.4-fold in MO-192 cells. Similar enhancement was found after transforming growth factor-beta (TGF-beta) and insulin-like growth factor-I (IGF-I) treatment. Combined treatment of the cells with EMF and the two growth factors TGF-beta and IGF-I did not act synergistically. MO-192 cells produced an osteoblast-characteristic extracellular matrix containing collagen type I, alkaline phosphatase, and osteocalcin, together with collagen type III, TP-1, and TP-3, two epitopes of an osteoblastic differentiation marker. The data suggest that the effects of EMFs on osteoblastic differentiation are comparable to those of TGF-beta and IGF-I. We conclude that EMF effects in the treatment of skeletal disorders and in orthopedic adjuvant therapy are mediated via enhancement of collagen type I mRNA expression, which may lead to extensive extracellular matrix synthesis.

[Intervention-adjusted intraoperative volume substitution--an example of surgical-anesthesiological cooperation]. / Eingriffsadaptierte intraoperative Volumensubstitution--Beispiel chirurgisch-anästhesiologischer Kooperation.

Since 1996 a simple classification of surgical interventions has been used to guarantee adequate intraoperative anesthesiological volume management. Use of this classification, including extension of operation and operative trauma, resulted in 45% less substitution with blood components in comparison to that observed in 1995.

Reconstitution of human telomerase with the template RNA component hTR and the catalytic protein subunit hTRT.

The maintenance of chromosome termini, or telomeres, requires the action of the enzyme telomerase, as conventional DNA polymerases cannot fully replicate the ends of linear molecules. Telomerase is expressed and telomere length is maintained in human germ cells and the great majority of primary human tumours. However, telomerase is not detectable in most normal somatic cells; this corresponds to the gradual telomere loss observed with each cell division. It has been proposed that telomere erosion eventually signals entry into senescence or cell crisis and that activation of telomerase is usually required for immortal cell proliferation. In addition to the human telomerase RNA component (hTR; ref. 11), TR1/TLP1 (refs 12, 13), a protein that is homologous to the p80 protein associated with the Tetrahymena enzyme, has been identified in humans. More recently, the human telomerase reverse transcriptase (hTRT; refs 15, 16), which is homologous to the reverse transcriptase (RT)-like proteins associated with the Euplotes aediculatus (Ea_p123), Saccharomyces cerevisiae (Est2p) and Schizosaccharomyces pombe (5pTrt1) telomerases, has been reported to be a telomerase protein subunit. A catalytic function has been demonstrated for Est2p in the RT-like class but not for p80 or its homologues. We now report that in vitro transcription and translation of hTRT when co-synthesized or mixed with hTR reconstitutes telomerase activity that exhibits enzymatic properties like those of the native enzyme. Single amino-acid changes in conserved telomerase-specific and RT motifs reduce or abolish activity, providing direct evidence that hTRT is the catalytic protein component of telomerase. Normal human diploid cells transiently expressing hTRT possessed telomerase activity, demonstrating that hTRT is the limiting component necessary for restoration of telomerase activity in these cells. The ability to reconstitute telomerase permits further analysis of its biochemical and biological roles in cell aging and carcinogenesis.

The role of the Src homology-2 domain in the lethal effect of Src expression in the yeast Saccharomyces cerevisiae.

Expression of the retroviral transforming gene v-src arrests the proliferation of the yeast Saccharomyces cerevisiae. A functional Src SH2 (Src homology 2) domain is required for this arrest. To examine the mechanism by which Src blocks yeast cell proliferation, and to determine the role of the Src SH2 domain in the growth arrest, src variants were expressed in yeast under the control of the galactose-inducible GAL1 promoter. Following galactose induction of Src expression, phosphotyrosyl-proteins were isolated by immunoprecipitation with beads coupled to either anti-phosphotyrosine antibody or to a recombinant fusion protein containing the Src SH2 domain. A group of SH2-binding phosphotyrosyl proteins was detected in cells expressing toxic forms of Src, but were not detected in cells expressing non-toxic variants. This group of phosphotyrosyl-proteins represents a minor subset of the proteins phosphorylated by v-Src. The lethality of v-Src and the phosphorylation of SH2-binding proteins were co-ordinately affected by alterations in phosphotyrosine-phosphatase activity. These observations indicate that the lethality of Src is correlated with the phosphorylation of proteins that bind to the Src SH2 domain. The role of the SH2 domain in determining the lethal effects of Src in yeast may be similar to its role in targeting Src to substrates necessary for its biological effects in vertebrate cells.

[Vertebral replacement in palliative tumor therapy. Possible surgical procedures--significant improvement in quality of life]. / Wirbelkörperersatz in der palliativen Tumortherapie. Mögliche Operationsverfahren--erhebliche Verbesserung der Lebensqualität.

Complications associated with spinal metastases encompass not only pain, but often neurological deficits and possibly even paralysis due to transverse lesions. The differential indication for dorsal, ventral and combined surgical procedures depends on the nature and extent of the tumor, and the life expectancy and general state of health of the patient. Surgery must be carried out in good time, before additional damage to the spinal cord occurs. In recent years, 20 patients have been treated by GHG-vertebral body replacement. In 19 of these patients, pain was considerably improved. All patients were able to walk following surgery. Preoperative neurological deficits disappeared, in 9 of 13 patients resulting in a major improvement in the patients' quality of life.

Influence of various irrigation fluids on articular cartilage.

When bovine articular cartilage was incubated in Ringer's solution, considerable amounts of proteoglycan were washed out of the cartilage. Thus, 4% of the proteoglycan was lost into the medium during an incubation of 4 hours. Subsequently, it was found that ionic aqueous media like saline or Ringer's solution extracted much more proteoglycan than ion-free media like distilled water or a variety of carbohydrate containing solutions. In separate experiments, it could be shown that solutions of 20% sorbitol and 2% mannitol exhibited particularly low proteoglycan extracting properties. It was found that the extraction of proteoglycan was dependent on the ion concentration in the aqueous media. The extraction of proteoglycan by sodium chloride was negligible at NaCl concentrations of 0.1% and lower. Proteoglycan loss from cartilage was only induced at 0.9% NaCl. Using intact rat femoral heads it could be shown that the elution of proteoglycan from cartilage occurred as well when the cartilage was intact. Here, the elution occurred at a slower rate but the differences between ionic and ion-free solutions were greater. By electronmicroscopic examination of bovine cartilage incubated in different media, it was observed that Ringer's solution induced a more uneven and rougher appearance of the cartilage surface than did 10% mannitol solution, indicating that probably a denudation of collagen fibers occurs on the loss of proteoglycan from the cartilage. Because the observed proteoglycan washout occurred within rather short periods of contact of the cartilage with the medium, it is concluded that this may be of relevance for the clinical situation during arthroscopic procedures. The use of preferably isotonic carbohydrate solutions like 5% mannitol is suggested to prevent unnecessary loss of proteoglycan from hyaline cartilage.

[Management of unstable fractures of the coxal femur. Selection of the appropriate osteosynthesis procedure in elderly patients]. / Versorgung instabiler Frakturen am koxalen Femurende. Auswahl des geeigneten osteosyntheseverfahrens beim alten Menschen.

Advantages and disadvantages of various fixation procedures for use in fractures of the femoral neck--blade-plate with temporary fixation by means of Kirschner wire insertion or dynamic hip screws--and hemi- or total allo-arthroplasty are described. The large number of fixation procedures for pertrochanteric fractures reflects the difficulty in achieving mobility and loading stability. On account of the possible intra- and postoperative complications, the highly propagated gamma nailing has proved problematic. Overall, the individual situation of the patient must be taken into account when choosing the appropriate fixation procedure.

Aberrant protein phosphorylation at tyrosine is responsible for the growth-inhibitory action of pp60v-src expressed in the yeast Saccharomyces cerevisiae.

Expression of pp60v-src, the transforming protein of Rous sarcoma virus, arrests the growth of the yeast Saccharomyces cerevisiae. To determine the basis of this growth arrest, yeast strains were constructed that expressed either wild-type v-src or various mutant v-src genes under the control of the galactose-inducible, glucose repressible GAL1 promoter. When shifted to galactose medium, cells expressing wild-type v-src ceased growth immediately and lost viability, whereas cells expressing a catalytically inactive mutant (K295M) continued to grow normally, indicating that the kinase activity of pp60v-src is required for its growth inhibitory effect. Mutants of v-src altered in the SH2/SH3 domain (XD4, XD6, SPX1, and SHX13) and a mutant lacking a functional N-terminal myristoylation signal (MM4) caused only a partial inhibition of growth, indicating that complete growth inhibition requires either targeting of the active kinase or binding of the kinase to phosphorylated substrates, or both. Cells arrested by v-src expression displayed aberrant microtubule structures, alterations in DNA content and elevated p34CDC28 kinase activity. Immunoblotting with antiphosphotyrosine antibody showed that many yeast proteins, including the p34CDC28 kinase, became phosphorylated at tyrosine in cells expressing v-src. Both the growth inhibition and the tyrosine-specific protein phosphorylation observed following v-src expression were reversed by co-expression of a mammalian phosphotyrosine-specific phosphoprotein phosphatase (PTP1B). However a v-src mutant with a small insertion in the catalytic domain (SRX5) had the same lethal effect as wild-type v-src, yet induced only very low levels of protein-tyrosine phosphorylation. These results indicate that inappropriate phosphorylation at tyrosine is the primary cause of the lethal effect of pp60v-src expression but suggest that only a limited subset of the phosphorylated proteins are involved in this effect.

Current state of cementless hip prostheses.

Cemented cups in the young patient continue to show an unacceptable rate of early aseptic loosening. A well designed cementless prosthesis, implanted with good technique, is a better alternative. With the uncertainty surrounding the femoral stem, a hybrid total hip with a cemented stem and porous ingrowth cup remains an acceptable interim solution. There is an ongoing problem with the wear debris produced by the available implant materials. There is hope that the newer materials will help in this regard. Custom made prostheses at this time, seem most suited for those hips with marked deformity making the use of standard systems difficult. The use of cement in the elderly population remains an acceptable technique with the advantages of immediate fixation and early weight bearing.

Custom made total knee-replacement in patients with primary and secondary bone tumors.

The authors present an account of a group of 51 patients to whom an individual endoprosthesis of the knee joint was implanted on account of a tumour. A primary bone tumour was involved in 42 cases and a metastatic process in 9 cases. Twenty-four endoprostheses were cemented, 26 were implanted without cement. The mean follow-up period was 43 months. Functional results excellent and good in 61%, poor results only in 5%.

Fatigue Fractures of First Generation Porous Coated Non-cemented Hip Prostheses.

We show two case reports to discuss the problem of fatigue fractures of non-cemented porous coated total hip prosthesis. Fatigue fractures occur in the region of highest tensile stresses. Because of the surface irregularities of the porous coating, tensile stresses in the surface of the stems are increased depending on the configuration of the pore. A thick porous coating also decreases the cross section of the stem. In addition the manufacturing process, the application of a porous layer can weaken the stem. Finally, cementless prostheses are implanted especially in young active patients, who exert high forces on their hip. For cementless porous coated hip prostheses, we need a standardized manufacturing process and test of the fatigue strength. In addition, there should be a minimum diameter of the core of the stem in order to avoid fatigue fractures. Key words: porous coated total hip prosthesis, fatigue fracture of the stem.

Effect of a founder event on variation in the genetic sex-determining system of the fire ant Solenopsis invicta.

Effects of a recent founder event on genetic diversity in wild populations of the fire ant Solenopsis invicta were studied, with particular attention given to the genetic sex-determining system. Diploid males are far more common relative to haploid males in introduced populations than in native populations of fire ants, and queens that produce diploid males account for a significantly larger proportion of the mated queens in introduced than in native populations. Differences between native and introduced populations in attributes of the mating systems (i.e., queen mating frequency or level of inbreeding) can be excluded as factors contributing to these different levels of diploid male production. Thus, we conclude that diploid males have increased in frequency in introduced populations because of a loss of allelic diversity at the sex-determining locus (loci). This loss of sex alleles has generated a substantial increase in the estimated segregational genetic load associated with production of sterile diploid males in introduced populations over the load in native populations. The loss of allelic diversity in the sex-determining system in introduced S. invicta is paralleled by a loss of electrophoretically detectable rare alleles at protein-encoding loci. Such concordance between these different types of markers is predicted because each of the many sex alleles present in the native populations is expected to be rare. Estimates of expected heterozygosity (Hexp) based on 76 electrophoretic loci do not differ significantly between the native and introduced fire ant populations, illustrating the lack of sensitivity of this measure for detecting many types of bottlenecks.

[Special endoprostheses of the knee joint in bone tumors]. / Spezialendoprothesen des Kniegelenks bei Knochentumoren.

Since the introduction of more effective adjuvant therapies in the area of primary and secondary bone tumors, limb salvage procedures have become more and more important. At the Orthopedic Department of the Technical University, Munich, 52 special knee prostheses have been implanted in patients with malignant tumors of the distal femur and proximal tibia. On the basis of the ISOLS criteria, the functional results achieved were excellent in 14%, good in 47%, satisfactory in 35%, and poor in only 5% of patients after an average follow-up period of 43 months (range: 3-156 months). The perioperative complication rate was 27%, and late complications were material fatigue and wear. In the case of primary tumors, a customized prostheses, and in the case of secondary tumors a modular system is recommended. Individual treatment planning is essential.