Sedan 2021 regleras medicintekniska produkter inom EU av förordningen MDR (EU 2017/745). Det primära syftet med regelverket är att säkerställa ändamålsenliga produkter med hög säkerhet. Det nya regelverket ställer högre krav på företag som tillverkar medicintekniska produkter samt andra aktörer inom den medicintekniska industrin. De mer omfattande kraven innebär att det blir mer utmanande att uppfylla samtliga kriterier som krävs för att kunna lansera medicintekniska produkter på unionsmarknaden. Detta examensarbete har undersökt hur företag som tillverkar specifika medicintekniska produkter som rullstolar och personlyftar upplever förutsättningarna för att nå marknaden. För att undersöka tidigare studier kring ämnet har en litteraturstudie genomförts och sedan utformades intervjufrågor med hjälp av samtliga handledare. Frågorna besvarades av företag som tillverkar rullstolar eller personlyftar. Som komplement till de semistrukturerade intervjuerna har upphandlingar undersökts med syfte att kartlägga vilka standarder som refereras till som skall-krav vid inköp av rullstolar och personlyftar. Resultatet visar att de ökade kraven påverkar större medicintekniska företag, men att mindre företag påverkas i högre utsträckning enligt intervjuobjekten. Dessutom noteras att standarder nämns mindre frekvent i upphandlingar än vad de intervjuade personerna hävdar. Slutligen anser intervjuobjekten att det är värdefullt att följa standarder vid utveckling och marknadsföring av personlyftar och rullstolar. / Since 2021, the Medical Device Regulation (MDR) has regulated medical devices within the EU (EU2017/745). The regulation’s primary purpose is to ensure fit-for-purpose products with high safety standards. The new regulatory framework imposes strict requirements on companies manufacturing medical devices and other actors within the medical device industry. The more extensive requirements make meeting all the criteria necessary for launching medical devices on the European Union market more challenging. This thesis has examined how companies that manufacture medical devices, especially wheelchairs and patient lifts, perceive the conditions for reaching the market. A literature review was conducted to examine previous studies on the subject. Then, interview questions were formulated with the assistance of supervisors to participate by companies manufacturing wheelchairs or patient lifts. Procurements were examined to complement the semi-structured interviews and map out which standards are mandatory requirements in procuring wheelchairs and patient lifts. The results indicate that the increased requirements affect larger medical device companies, but the interviewees say smaller companies are more affected.  Additionally, standards are mentioned less frequently in procurements than what the interviewed individuals claim. Finally, the semi-structured interviews revealed that the interviewees consider it valuable to adhere to standards in developing and marketing wheelchairs and patient lifts.

Vid handkirurgiska kliniken på Södersjukhuset i Stockholm (SÖS) har ett projekt med målet att utföra en handtransplantation pågått under flera år. I projektet har man tagit fram två egentillverkade produkter, ett sågblock för att förenkla sågningen genom ben samt en uppsättning med brickor för märkning av olika strukturer i handen. Målet med denna rapport var att ta fram underlag som kan användas för att bestämma om produkterna är lämpliga att använda vid transplantationen. Lämpligheten utvärderades utifrån de medicintekniska regelverken samt analys av risker. För att bedöma hur produkterna förhöll sig till kraven i regelverken studerades EU:s förordning 2017/745 Medical Device Regulation (MDR) samt de svenska författningar som kompletterar denna. Varje krav analyserades för båda produkterna och en motivering upprättades kring dess relevans samt huruvida produkten klarade kravet. En riskhanteringsprocess genomfördes för att identifiera och utvärdera riskerna kopplat till den kliniska användningen.  Riskhanteringen visade att användning av produkterna kan medföra fem risker för respektive produkt, där två av riskerna för brickorna inte gick att utvärdera på grund av bristande information kring materialet. Övriga risker för båda produkterna bedömdes som relativt lindriga. Gällande regelverken nådde produkterna inte upp till flera av kraven, mycket på grund av otillräcklig dokumentation och testning samt avsaknad av rutiner för att bevisa uppfyllnad av kraven.  Slutsatsen som drogs var att denna rapport delvis kan användas som underlag för att bestämma lämpligheten av produkterna. Dock krävs ytterligare arbete för att kunna bevisa att produkterna helt når upp till kraven i regelverken och således garanteras vara säkra att använda. / The clinic for hand surgery at Södersjukhuset in Stockholm (SÖS) has for several years been working on a project with the aim to perform a hand transplantation. As a part of this project two self-manufactured medical devices have been produced, one surgical guide to facilitate sawing through the bones and one set of tags to mark different structures in the hand. The aim with this report was to produce a basis that could be used to decide whether the products are suitable to use during the transplantation. The suitability was evaluated based on medical device regulations and analyzing the risks. To assess how well the products met the requirements from the regulations, relevant constitutions were studied (EU 2017/745 Medical Device Regulation (MDR) and the Swedish constitutions that complement MDR). Every requirement’s relevance and fulfillment were motivated for both products. A risk management process was implemented to identify and evaluate the risks. The result from the risk management process showed that usage of the products could entail five risks for each product, where two of the risks for the tags could not be evaluated due to lack of information about the material. The other risks for both products were assessed as relatively mild. Regarding the regulations, the products did not meet several of the requirements, mainly due to insufficient documentation and testing together with lack of routines to prove compliance with the requirements. The conclusion was that this report could partly be used as a basis for determining the suitability of the products. Though, further work is required to be able to prove that the products meet the requirements from the regulations and thus are safe to use.

La chimiorésistance des cancers est caractérisée par une résistance pléïotropique à de multiples médicaments. Ce mécanisme est en partie causé par la surexpression des transporteurs à "ATP binding cassette" (Pgp, MRP1, BCRP...). Les inhibiteurs connus de ces transporteurs comme la cyclosporine A, le vérapamil et le RU486 sont toxiques à doses élevées. Dans cette étude, de nombreux dérivés stéroïdiens synthétisés au laboratoire à base de progestérone ou d'acides biliaires ont été évalués pour leur capacité à inhiber les transporteurs ABC et plus spécifiquement les fonctions de transport par la Pgp ou la BCRP. Plusieurs de ces dérivés synthétisés se sont avérés capables de restaurer complètement la sensibilité des cellules résistantes d'une manière plus importante que la cyclosporine A in vitro. De plus, le meilleur des nos dérivés testés s'est avéré capable in vivo de diminuer significativement la progression tumorale de xénogreffe sur les souris et d'augmenter la durée de survie des souris. Cette étude a ainsi permis d'ouvrir la voie au développement de nouveaux dérivés stéroïdiens peu toxiques ayant la capacité d'inhiber le phénotype MDR et de restaurer la sensibilité des cellules cancéreuses vis-à-vis des agents chimiothérapeutiques utilisés, avec un perspective d'application clinique

Primary brain tumours, and especially the most common form malignant gliomas, usually display a pronounced resistance to other treatment modalities when surgery fails to cure. Growth factors, such as EGF and its receptor, frequently amplified and overexpressed in malignant gliomas, and factors associated with multidrug resistance have been suggested to at least partially explain the poor outcome. The aim of this thesis was to characterise factors in primary brain tumours associated with the development of resistance with focus on the epidermal growth factor receptor (ErbB) family, and multidrug resistance (MDR). Influences of irradiation on the expression and activity of P-glycoprotein (Pgp) in malignant gliomas was evaluated. The effects showed that irradiation increased the efflux activity of Pgp in rat brain vascular endothelial cells, but not in glioma cells. In the intracranial BT4C glioma model, Pgp was detected in the capillary endothelium in the tumour tissue but not in glioma cells. Expression of several factors coupled to MDR (Pgp, MRP1, LRP, and MGMT) in primary brain tumours were analysed and correlated to clinical data. In gliomas, Pgp and MRP1 were predominantly observed in capillary endothelium and in scattered tumour cells, whereas LRP occurred only in tumour cells. In meningiomas, expression of the analysed markers was demonstrated in the capillary endothelium, with a higher expression of Pgp and MRP1 in transitional compared to meningothelial meningiomas. A pronounced expression of MGMT was found independently of the histopathological grade or tumour type. Survival analysis indicated a shorter overall survival for patients suffering from low-grade gliomas with high expression of Pgp. To explore the importance of the epidermal growth factor receptor (EGFR), expression levels of the family members (EGFR, ErbB2-4) were analysed and their relations to various clinical parameters were evaluated in gliomas and meningiomas. In gliomas, the highest EGFR expression was observed in high-grade tumours, while ErbB4 expression was most pronounced in low-grade tumours. In meningiomas, expression of EGFR, ErbB2, and ErbB4 was observed in the majority of the tumours. An intriguing observation in low-grade gliomas was a significantly decreased overall survival for patients with high EGFR protein expression. The effects of different time schedules for administration of the selective EGFR inhibitor ZD1839 in relation to irradiation of glioma cells were analysed. The analyses showed a heterogeneity in the cytotoxic effects of ZD1839 between cell lines, and it was obvious that some of the cell lines showed sensitivity to ZD1839 despite no or low expression of EGFR. The study also demonstrated the importance of timing of ZD1839 administration when this agent is combined with irradiation. In conclusion, in order to enhance the efficacy of radiotherapy by various drugs in malignant gliomas it may be essential to inhibit drug efflux activity in endothelial cells and to deliver drugs in an optimal timing in relation to radiotherapy. The heterogeneity in expression of drug resistance markers, as well as the ErbB family reflects the complexity in classification of primary brain tumours, and indicates that subgroups of patients with low-grade gliomas expressing Pgp and EGFR might benefit from more aggressive and individualised treatment.

The phenomenon called multi drug resistance (MDR) is the resistance of cancer cells to anticancer drugs before or during chemotherapy. One of the mechanisms causing MDR is the upregulation of efflux pumps. The overexpression of MDR1 and MRP1 results in increased efflux of anticancer agents. The aim of this study was to reverse MDR1-mediated paclitaxel resistance in MCF7 breast cancer cell line by a chemical MDR modulator elacridar. In this study, cytotoxicity and the reversal effect of elacridar on sensitive and paclitaxel resistant cells were investigated. The effect of elacridar on MDR1 and MRP1 gene expressions were also determined. Results indicated MDR1 gene was highly overexpressed (208 fold) in MCF7/Pac cells compared to MCF7/S cells. Elacridar was not found to be cytotoxic in MCF7/Pac cells up to 30&micro / M. XTT results demonstrated 0.5&micro / M elacridar concentration was able to restore the antiproliferative effect of paclitaxel by 94% in MCF7/Pac cells. Complete MDR reversal was achieved at 5&micro / M elacridar concentration. qPCR results revealed dose dependent upregulations in MDR1 and MRP1 gene expression levels after elacridar treatment which did not prevent reversal of MDR by elacridar. Elacridar was shown to be very effective against paclitaxel resistance in MCF7/Pac cells at low concentrations. Therefore, it can be a suitable candidate for therapeutic applications in patients who developed paclitaxel resistance. Nevertheless, dose dependent upregulations in MDR1 and MRP1 gene expressions should be taken into consideration and overdose elacridar administration should be avoided.

Resistance to anticancer drugs is a serious obstacle to cancer chemotherapy. A common form of multidrug resistance (MDR) is caused by the overexpression of transmembrane transporter proteins P-glycoprotein and MRP1, encoded by MDR1 and MRP1 genes, respectively. These proteins lead to reduced intracellular drug concentration and decreased cytotoxicity by means of their ability to pump the drugs out of the cells. Breast cancer tumor resistance is mainly associated with overexpression of P-gp/MDR1. Although some chemical MDR modulators aim to overcome MDR by impairing the function of P-gp, they exhibit severe toxicities limiting their clinical relevance. Consequently, selective blocking of the expression of P-gp/MDR1 specific mRNA through RNA interference strategy may be an efficient tool to reverse MDR phenotype and increase the success of chemotherapy. Aim of this study was re-sensitizing doxorubicin resistant breast cancer cells to anticancer agent doxorubicin by selective downregulation of P-gp/MDR1 mRNA. The effect of the selected MDR1 siRNA and MRP1 expression after MDR1 silencing was determined by qPCR analysis. XTT cell proliferation assay was performed to v determine the effect of MDR1 silencing on doxorubicin sensitivity.Intracellular drug accumulation and localization was investigated by confocal laser scanning microscopy after treatment with MDR1 siRNA or other MDR modulators / verapamil or promethazine. The role of P-gp in migration characteristics of resistant cells was evaluated by wound healing assay. The results demonstrated that approximately 90% gene silencing occurred by the selected siRNA targeting MDR1 mRNA. However the level of MRP1 mRNA did not change after MDR1 downregulation. Introduction of siRNA resulted in about 70% re-sensitization to doxorubicin. Silencing of P-gp encoding MDR1 gene resulted in almost complete restoration of the intracellular doxorubicin accumulation and re-localization of the drug to the nuclei. Despite the considerably high concentration of the modulators, verapamil and promethazine were not as effective as siRNA for reversal of the drug efflux. According to wound healing assay, MDR1 silencing did not have any effect on migration characteristics of resistant cells, that is, P-gp expression does not seem to affect the motility of the cells. Selected siRNA duplex was shown to effectively inhibit MDR1 gene expression, restore doxorubicin accumulation and localization, and enhance chemo-sensitivity of resistant cells, which makes it a suitable future candidate for therapeutic applications.

Reproduction de : Thèse doctorat : Pharmacie. Biologie cellulaire et moléculaire : Reims : 2006. / Titre provenant de l'écran-titre. Bibliogr. p.198-229.

Tuberculosis (TB) is the most common opportunistic infection in HIV-infected patients and the emergence of drug-resistant tuberculosis (DR-TB) is a growing problem in resource-limited settings (RLS). TB diagnosis in most RLS still depends on smear microscopy for acid-fast bacilli (AFB) while adequate infrastructure for testing drug sensitivity is unavailable. However, molecular diagnostics that detect Mycobacterium tuberculosis (Mtb) DNA and its genetic markers of drug resistance were recently developed. In this thesis I describe the use of a molecular diagnostic, Genotype MTBDRplus, for characterizing DR-TB and patterns of tuberculosis-like infection in two cities in south-west and north-central Nigeria. I found high rates of DR-TB in Nigerian HIV-infected individuals (9.3% for RIF or INH) with significantly different amounts by location (18.18% in south-west vs. 3.91% in north-central Nigeria, p=0.01). RIF resistance, indicative of MDR-TB, was found in 5.52% treatment-naïve patients, far exceeding the WHO predictions (0-4.3%). Furthermore, RIF resistance was genetically distinct, suggesting location-specific transmission of drug resistance (p=0.04). Genotype MTBDRplus correctly identified the drug-resistant samples compared to sequencing in 96.8% of cases. Mtb was confirmed in 56% of patients and was less likely to be found in patients on ART, while controlling for other relevant demographic characteristics (OR 0.29, P=0.02). Only abnormal respiratory findings on auscultation and the direct sputum smear grade greater than 3/100 were significant predictors of Mtb infection (OR 3.28, P=0.03; OR 6.40, p<0.01 respectively). Concentrated sputum smear was not significantly correlated with Mtb infection, except at the highest grades (>2+). Furthermore, in 49% of samples that were not confirmed for Mtb other actinomycetes were found: atypical Mycobacteria (ATM), Rhodococcus spp., Nocardia spp., Corynebacterium spp. I conclude that concentrated sputum AFB smears may misidentify bacteria as Mtb in a subset of HIV-infected patients. These individuals may have a different, even uncharacterized, actinomycete infection in the respiratory tract. Furthermore, total DR-TB in HIV-infection is high and transmission of DR-TB in HIV-infected patients in Nigeria is higher than estimated by the WHO. Molecular diagnostics are a rapid method for identifying Mtb and monitoring DR-TB, and can guide appropriate treatment decisions for respiratory infections in RLS with a high HIV burden.

P-glycoprotein (Pgp, ABCB1) is a polyspecific efflux transporter implicated in multidrug resistance in human cancers. In this study, tetramethylrhodamine-5-carbonyl azide (AzTMR) was covalently crosslinked to the Pgp drug binding pocket with a stoichiometry of 1. The Pgp-AzTMR adduct was functionally equivalent to unlabelled Pgp and retained its ability to transport Hoechst 33342. The binding site of AzTMR in Pgp was nonpolar, with a similar environment to that of propanol. Pgp-AzTMR could bind a second drug molecule, with a higher affinity for H-site drugs and lower affinity for other R-site drugs. Unlabelled Pgp interacted with dimeric versions of known Pgp modulators, binding them with higher affinity than the monomer. These compounds were also found to either stimulate or inhibit Pgp ATPase activity depending on the concentration. Pgp-AzTMR was able to bind dimeric drugs, indicating that 3 substrate moieties can fit into the binding pocket. / The Canadian Cancer Society

The objective of this dissertation is to study the mechanism by which HIV protease inhibitors enter into the central nervous system (CNS) and breast milk of rats, and what effects MDR modulators have on the distribution and metabolism of HIV protease inhibitors. The transporter P-glycoprotein (P-gp) has been shown to limit the distribution of HIV protease inhibitors into the CNS of rodents. This thesis examined the effects of GF120918, an MDR modulator, on the CNS distribution of amprenavir, an HIV protease inhibitor, in rats. GF120918 significantly increased the unbound CNS concentrations of amprenavir without altering the unbound blood concentrations of amprenavir. The results of these studies show that GF120918 can inhibit P-gp at the blood brain barrier (BBB) to increase the unbound CNS concentration of amprenavir and potentially other HIV protease inhibitors. Many first generation MDR modulators inhibited both P-gp transport and CYP3A metabolism. Therefore, a principal goal of this thesis was to determine if GF120918 could selectively inhibit P-gp transport without inhibiting CYP3A metabolism. Using in vitro (human) and in vivo (rat) studies, GF120918 selectively inhibited P-gp at the BBB without inhibiting CYP3A metabolism. The transporter MRP1 has been shown to both transport HIV protease inhibitors and expressed in the CNS. Studies contained in the thesis have shown that mrp1 is not localized to the BBB of rats, therefore, mrp1 is unlikely to play a significant role in the distribution of HIV protease inhibitors into the CNS of rats. The distribution of nelfinavir, an HIV protease inhibitor, into rat breast milk was studied in the thesis as a first approach in understanding the extent to which HIV protease inhibitors can accumulate into milk. The concentration of nelfinavir in rat milk was approximately half that of plasma. P-gp protein expression was detected in lactating rat mammary tissue. However, GF120918 showed no effect on the distribution of nelfinavir into rat milk suggesting that P-gp does not play a significant role in the distribution of HIV protease inhibitors into milk.