Prosthetic joint infections: new diagnostic and therapeutic strategies

A prosthetic joint infection (PJI) is a severe complication after arthroplasty. From the current thesis, three main conclusion can be drawn regarding diagnosis and treamtent of PJI. (a) Accurate self-monitoring of postoperative wounds after joint implantation helped elucidate the course of wound leakage and its association with acute prosthetic joint infections. (b) The collection of clinical data on different antimicrobial treatment strategies provided insight into the effectiveness of different treatment options for patients with a prosthetic joint infection. In this thesis, we report that personalized antimicrobial treatment for prosthetic joint infections is possible without compromising the effectiveness of treatment. (c) this thesis describes the role and importance of new anti-persister drugs against biofilm-associated infections. We developed a biofilm model that closely resembles the clinic of a prosthetic joint infection. Based on the results described in this thesis, future research will be aimed at better understanding the pathogenesis of biofilms. This should ultimately lead to better treatment options for patients with a prosthetic joint infection.Zorg en Zekerheid; Stichting de Merel; Innovatiefonds ZorgverzekeraarsLUMC / Geneeskund

Outcomes of amputation due to long-standing therapy-resistant complex regional pain syndrome type I

Objective: To assess long-term outcomes of amputation in patients with long-standing therapy-resistant complex regional pain syndrome type I (CRPS-I). Design: Partly cross-sectional, partly longitudinal study. Subjects: Patients who had amputation of a limb due to long-standing, therapy-resistant CRPS-I, at the University Medical Centre Groningen, The Netherlands, between May 2000 and September 2015 (n=53) were invited to participate. Methods: Participants were interviewed in a semi-structured way regarding mobility, pain, recurrence of CRPS-I, quality of life, and prosthesis use. Those who reported recurrence of CRPS-I underwent physical examination. Results: A total of 47 patients (median age at time of amputation, 41.0 years; 40 women) participated. Longitudinal evaluation was possible in 17 participants. Thirty-seven participants (77%) reported an important improvement in mobility (95% confidence interval (95% CI) 63; 87%). An important reduction in pain was reported by 35 participants (73%; 95% CI 59; 83%). CRPS-I recurred in 4 of 47 participants (9%; 95% CI 3; 20%), once in the residual limb and 3 times in another limb. At the end of the study of the 35 participants fitted with a lower limb prosthesis, 24 were still using the prosthesis. Longitudinal evaluation showed no significant deteriorations. Conclusion: Amputation can be considered as a treatment for patients with long-standing, therapy-resistant CRPS-I. Amputation can increase mobility and reduce pain, thereby improving the quality of patients' lives. However, approximately one-quarter of participants reported deteriorations in intimacy and self-confidence after the amputation

Rifampin for staphylococcal prosthetic joint infection: do we still need a randomized controlled trial?

Immunogenetics and cellular immunology of bacterial infectious disease

Early multidrug resistance, defined by changes in intracellular doxorubicin distribution, independent of P-glycoprotein.

Resistance to multiple antitumour drugs, mostly antibiotics or alkaloids, has been associated with a cellular plasma membrane P-glycoprotein (Pgp), causing energy-dependent transport of drugs out of cells. However, in many common chemotherapy resistant human cancers there is no overexpression of Pgp, which could explain drug resistance. In order to characterise early steps in multidrug resistance we have derived a series of P-glycoprotein-positive (Pgp/+) and P-glycoprotein-negative (Pgp/-) multidrug resistant cell lines, from a human non-small cell lung cancer cell line, SW-1573, by stepwise selection with increasing concentrations of doxorubicin. These cells were exposed to doxorubicin and its fluorescence in nucleus (N) and cytoplasm (C) was quantified with laserscan microscopy and image analysis. The fluorescence N/C ratio in parent cells was 3.8 and decreased both in Pgp/+ and Pgp/- cells with increasing selection pressure to 1.2-2.6 for cells with a resistance factor of 7-17. N/C ratios could be restored partly with verapamil only in Pgp/+ cells. N/C ratio measurements may define a general Pgp-independent type of defense of mammalian cells against certain anticancer agents which may precede Pgp expression in early doxorubicin resistance

Altered MRP is associated with multidrug resistance and reduced drug accumulation in human SW-1573 cells.

We have analysed the contribution of several parameters, e.g. drug accumulation, MDR1 P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP) and topoisomerase (topo) II, to drug resistance in a large set of drug-resistant variants of the human non-small-cell lung cancer cell line SW-1573 derived by selection with low concentrations of doxorubicin or vincristine. Selection with either drug nearly always resulted in MDR clones. The resistance of these clones could be explained by reduced drug accumulation and was associated with a decrease rather than an increase in the low MDR1 mRNA level. To test whether a decrease in MDR1 mRNA indirectly affected resistance in these cells, we introduced a MDR1-specific hammerhead ribozyme into wild-type SW-1573 cells. Although this led to a substantial reduction in MDR1 mRNA, it did not result in resistance. In all resistant clones we found an altered form of the multidrug resistance-associated protein (MRP), migrating slightly slower during SDS-polyacrylamide gel electrophoresis than MRP in parental cells. This altered MRP was also present in non-P-gp MDR somatic cell hybrids of the SW-1573 cells, demonstrating a clear linkage with the MDR phenotype. Treatment of crude cellular membrane fractions with N-glycanase, endoglycosidase H or neuraminidase showed that the altered migration of MRP on SDS-PAGE is due to a post-translational modification. There was no detectable difference in sialic acid content. In most but not all doxorubicin-selected clones, this MDR phenotype was accompanied by a reduction in topo II alpha mRNA level. No reduction was found in the clones selected with vincristine. We conclude from these results that selection of the SW-1573 cell line for low levels of doxorubicin or vincristine resistance, predominantly results in MDR with reduced drug accumulation associated with the presence of an altered MRP protein. This mechanism can be accompanied by other resistance mechanisms, such as reduced topo II alpha mRNA in case of doxorubicin selection

Temperament Traits and Psychopathology in Young Clinically Referred Children Compared to a General Population Sample

Evidence from general population studies shows the contribution of various temperament traits to the development of child psychopathology. Little is known about which traits are associated with internalizing and externalizing problems in young clinically referred children. The current study assessed temperament and internalizing and externalizing problems in 216 referred children (M = 4.35 years, SD 0.89, 81% boys). A comparison was made with an age and gender matched general population sample. Referred children showed less effortful control than general population children. Less effortful control and more negative affectivity were associated with more internalizing and externalizing problems across groups. Surgency, and specifically temperamental impulsivity, was more strongly associated with externalizing problems in referred children compared to general population. Less soothability, less inhibitory control and more frustration predicted (sub)clinical levels of comborbid internalizing and externalizing problems in referred children. The results can be used in diagnostic and treatment procedures in early childhood