Implants of small joints

The wrist joints are often involved early in rheumatoid arthritis (RA). Small joints of wrist can be affected by hand arthritis leading to pain and deformity of the joints. Pros-thetic development must take in to consideration range of motion, stability, fixation, ease of implantation, biocompatibility and soft tissue resconstruction. The metacarpophalan-geal, interphalangeal and trapeziometacarpal joints each present different problems in the design of prostheses.This thesis focused on the arthritis of the basal joint of the thumb which most often affects middle-aged women. Basal joint is formed by carpometacarpal (CMC) joint and trapezium bone. Several surgical techniques have been described for management of degenarative basal joint changes. These include excision of the trapezium alone, ligament reconstruction with or with out tendon interposition (LRTI) and trapezium resection, arthrodesis and multiple arthroplasty options using biologic and synthetic implants, including silastic prostheses, metal prostheses and allograft interpositions. This study reviewed the literature related to the implants for trapezium bone failures in hand arthritis and also compared the techniques of joint arthroplasty for rheumatoid arthritis (RA). Trapezium bone is the main common area in osteoarthritis of the hand. Researchers found out, successful and durable results with ligament reconstruction with or without tendon interposition.However pinch strength was not satisfactory due to short-ening of the thumb by trapeziectomy. Joint arthroplasty can aid maintenance of the length of the thumb and provide greater pinch strength. Clinical assessments such as rate of mo-tion (ROM), grip and pinch strength can evaluate the quality and durability of each tech-nique. Several studies about silicone implants reported implant wear, synovitis and oste-olysis. Metallic implants resulted in implant loosening and instability. Researchers found out a porous poly-L/D-lactide copolymer implant with an L: D monomer ratio of 96:4 (P (L/D) LA 96/4) resulted significiant strength and can be replaced with fibrous tissue in 2-3 years. Silicone implant is better at palmar stability compared to PLDLA (poly-L/D-lactide copolymer) implant, whereas lack of silicone synovitis and osteolysis are the ad-vantages of the PLDLA implant. For achieving definite results, longer follow-ups are needed for synthetic allograft and PLDLA implants

A Microfluidic Chip Architecture Enabling a Hypoxic Microenvironment and Nitric Oxide Delivery in Cell Culture

A hypoxic (low oxygen level) microenvironment and nitric oxide paracrine signaling play important roles in the control of both biological and pathological cell responses. In this study, we present a microfluidic chip architecture for nitric oxide delivery under a hypoxic microenvironment in human embryonic kidney cells (HEK-293). The chip utilizes two separate, but interdigitated microfluidic channels. The hypoxic microenvironment was created by sodium sulfite as the oxygen scavenger in one of the channels. The nitric oxide microenvironment was created by sodium nitroprusside as the light-activated nitric oxide donor in the other channel. The solutions are separated from the cell culture by a 30 µm thick gas-permeable, but liquid-impermeable polydimethylsiloxane membrane. We show that the architecture is preliminarily feasible to define the gaseous microenvironment of a cell culture in the 100 µm and 1 mm length scales

A Microfluidic Chip Architecture Enabling a Hypoxic Microenvironment and Nitric Oxide Delivery in Cell Culture

A hypoxic (low oxygen level) microenvironment and nitric oxide paracrine signaling play important roles in the control of both biological and pathological cell responses. In this study, we present a microfluidic chip architecture for nitric oxide delivery under a hypoxic microenvironment in human embryonic kidney cells (HEK-293). The chip utilizes two separate, but interdigitated microfluidic channels. The hypoxic microenvironment was created by sodium sulfite as the oxygen scavenger in one of the channels. The nitric oxide microenvironment was created by sodium nitroprusside as the light-activated nitric oxide donor in the other channel. The solutions are separated from the cell culture by a 30 µm thick gas-permeable, but liquid-impermeable polydimethylsiloxane membrane. We show that the architecture is preliminarily feasible to define the gaseous microenvironment of a cell culture in the 100 µm and 1 mm length scales

A microfluidic oxygen sink to create a targeted cellular hypoxic microenvironment under ambient atmospheric conditions

Physiological oxygen levels within the tissue microenvironment are usually lower than 14%, in stem cell niches these levels can be as low as 0-1%. In cell cultures, such low oxygen levels are usually mimicked by altering the global culture environment either by O-2 removal (vacuum or oxygen absorption) or by N-2 supplementation for O-2 replacement. To generate a targeted cellular hypoxic microenvironment under ambient atmospheric conditions, we characterised the ability of the dissolved oxygen-depleting sodium sulfite to generate an in-liquid oxygen sink. We utilised a microfluidic design to place the cultured cells in the vertical oxygen gradient and to physically separate the cells from the liquid. We demonstrate generation of a chemical in-liquid oxygen sink that modifies the surrounding O-2 concentrations. O-2 level control in the sink-generated hypoxia gradient is achievable by varying the thickness of the polydimethylsiloxane membrane. We show that intracellular hypoxia and hypoxia response element-dependent signalling is instigated in cells exposed to the microfluidic in-liquid O-2 sink-generated hypoxia gradient. Moreover, we show that microfluidic flow controls site-specific microenvironmental kinetics of the chemical O-2 sink reaction, which enables generation of intermittent hypoxia/re-oxygenation cycles. The microfluidic O-2 sink chip targets hypoxia to the cell culture microenvironment exposed to the microfluidic channel architecture solely by depleting O-2 while other sites in the same culture well remain unaffected. Thus, responses of both hypoxic and bystander cells can be characterised. Moreover, control of microfluidic flow enables generation of intermittent hypoxia or hypoxia/re-oxygenation cycles. (C) 2018 Published by Elsevier Ltd on behalf of Acta Materialia Inc.Peer reviewe

Transcriptomic Profiling of JEG-3 cells using human leiomyoma derived matrix

Peer reviewe

MODIFICATION OF CELLULAR GASEOUS MICROENVIRONMENT ON GAS-PERMEABLE MICROFLUIDIC CHIPS

The decreased oxygen availability activates the cells' hypoxia- inducible factor (HIF) pathway. HIF is a critical mediator of physiological responses in acute and chronic hypoxia. Conventional hypoxia chambers, which are widely employed to study hypoxia, are cumbersome and require large gas supply volumes. The high diffusivity of gases makes it impossible to control the local gaseous microenvironments in hypoxia chambers. In this study, microfluidic chips were utilized to create oxygen gradients in nano and micro scales to act as gaseous microenvironments for cell cultures. It was observed that by pumping an oxygen scavenger solution in the microfluidic channels, the hypoxia response increased in the adherent cells on the microchip system. A simultaneous cellular gaseous microenvironment for hypoxia and nitric oxide was created by utilizing a microfluidic channel architecture with two sets of microchannels. One of the channels was filled with the oxygen scavenger solution and the other with a nitric oxide donor (sodium nitroprusside, SNP). The channels then guided these treatments to selected areas of the cell culture. We showed that microfluidics could target the specific region in the chip and modify microenvironmental gases in the cells. At the same time, the other cultural area remained unchanged. A simultaneous cellular response to hypoxia and nitric oxide was obtained after 100 min pumping with a flowrate of 1.6 μl/min. Preeclampsia (PE) is a pregnancy disorder where hypoxia plays a crucial role in the pathophysiology. To mimic a preeclampsia (PE) microenvironment, an oxygen scavenger solution was pumped through the microfluidic channels of a Myogel-coated microchip on which JEG-3 choriocarcinoma cells were cultured as a human trophoblast model for 24h. RNAseq data of the cells from the microchip showed gene expression differences and pathways that were affected by hypoxia; among those were MYC targets, E2F targets, G2-M checkpoint, and the unfolded protein response. Based on our data, the hypoxia created by the microchip caused significant transcriptional changes in JEG-3 cells.Vähentynyt hapen saanti aktivoi solujen hypoksian indusoivan tekijän (HIF) säätelyreitin. HIF on tärkeä fysiologisten vasteiden välittäjä akuutissa ja kroonisessa hypoksiassa. Perinteiset hypoksiakammiot, joita käytetään laajasti hypoksia tutkimuksessa, ovat hankalia ja vaativat suurta kaasunsyöttömäärää. Kaasujen voimakas diffuusio tekee mahdottomaksi säädellä paikallisesti kaasumaisia mikroympäristöjä hypoksiakammioissa. Tässä tutkimuksessa mikrofluidistisilla siruilla luotiin happigradientteja nano- ja mikromittakaavassa, toimimaan kaasumaisena mikroympäristönä soluviljelmille. Havaitsimme, että pumppaamalla hapenpoistoliuosta mikrofluidistisiin kanaviin hypoksiavaste lisääntyi mikrosirujärjestelmän soluissa. Samanaikainen solun kaasumainen mikroympäristö hypoksialle ja typpioksidille luotiin käyttämällä mikrofluidistisia siruja kahdella mikrokanavasarjalla. Toinen kanavista täytettiin hapenpoistoliuoksella ja toinen typpioksidin luovuttajalla (natriumnitroprussidi, SNP). Kanavat kohdensivat sitten kaasujen muutokset soluviljelmän valituille alueille. Osoitimme, että mikrofluidistiikan avulla voi kohdistaa muutokset tietylle alueelle sirussa ja muokata mikroympäristön kaasuja soluissa. Samaan aikaan muut viljelmän olosuhteet säilyivät ennallaan. Samanaikainen soluvaste hypoksialle ja typpioksidille saatiin 100 minuutin pumppauksen jälkeen virtausnopeudella 1.6 µl/min. Pre-eklampsia (PE) on raskaushäiriö, jonka patofysiologiassa hypoksialla on ratkaiseva rooli. Pre-eklampsian mikroympäristön jäljittelemiseksi hapenpoistoliuosta pumpattiin Myogeeli-pinnoitetun mikrosirun mikrofluidististen kanavien läpi, joissa JEG-3 koriokarsinoomasoluja viljeltiin ihmisen trofoblastimallina 24 tunnin ajan. Mikrosirun solujen RNAseq-profilointi osoitti hypoksian vaikuttavan geenien ilmentymistasoihin ja säätelyreitteihin; näiden joukossa olivat MYC-kohteet, E2F-kohteet, G2-M-tarkastuspiste ja vaste laskostumattomille proteiineille. Tulosten perusteella mikrosirun tuottama hypoksia aiheutti merkittäviä transkription muutoksia JEG-3-soluissa

Implants of small joints

The wrist joints are often involved early in rheumatoid arthritis (RA). Small joints of wrist can be affected by hand arthritis leading to pain and deformity of the joints. Pros-thetic development must take in to consideration range of motion, stability, fixation, ease of implantation, biocompatibility and soft tissue resconstruction. The metacarpophalan-geal, interphalangeal and trapeziometacarpal joints each present different problems in the design of prostheses.This thesis focused on the arthritis of the basal joint of the thumb which most often affects middle-aged women. Basal joint is formed by carpometacarpal (CMC) joint and trapezium bone. Several surgical techniques have been described for management of degenarative basal joint changes. These include excision of the trapezium alone, ligament reconstruction with or with out tendon interposition (LRTI) and trapezium resection, arthrodesis and multiple arthroplasty options using biologic and synthetic implants, including silastic prostheses, metal prostheses and allograft interpositions. This study reviewed the literature related to the implants for trapezium bone failures in hand arthritis and also compared the techniques of joint arthroplasty for rheumatoid arthritis (RA). Trapezium bone is the main common area in osteoarthritis of the hand. Researchers found out, successful and durable results with ligament reconstruction with or without tendon interposition.However pinch strength was not satisfactory due to short-ening of the thumb by trapeziectomy. Joint arthroplasty can aid maintenance of the length of the thumb and provide greater pinch strength. Clinical assessments such as rate of mo-tion (ROM), grip and pinch strength can evaluate the quality and durability of each tech-nique. Several studies about silicone implants reported implant wear, synovitis and oste-olysis. Metallic implants resulted in implant loosening and instability. Researchers found out a porous poly-L/D-lactide copolymer implant with an L: D monomer ratio of 96:4 (P (L/D) LA 96/4) resulted significiant strength and can be replaced with fibrous tissue in 2-3 years. Silicone implant is better at palmar stability compared to PLDLA (poly-L/D-lactide copolymer) implant, whereas lack of silicone synovitis and osteolysis are the ad-vantages of the PLDLA implant. For achieving definite results, longer follow-ups are needed for synthetic allograft and PLDLA implants

MODIFICATION OF CELLULAR GASEOUS MICROENVIRONMENT ON GAS-PERMEABLE MICROFLUIDIC CHIPS

The decreased oxygen availability activates the cells' hypoxia- inducible factor (HIF) pathway. HIF is a critical mediator of physiological responses in acute and chronic hypoxia. Conventional hypoxia chambers, which are widely employed to study hypoxia, are cumbersome and require large gas supply volumes. The high diffusivity of gases makes it impossible to control the local gaseous microenvironments in hypoxia chambers. In this study, microfluidic chips were utilized to create oxygen gradients in nano and micro scales to act as gaseous microenvironments for cell cultures. It was observed that by pumping an oxygen scavenger solution in the microfluidic channels, the hypoxia response increased in the adherent cells on the microchip system. A simultaneous cellular gaseous microenvironment for hypoxia and nitric oxide was created by utilizing a microfluidic channel architecture with two sets of microchannels. One of the channels was filled with the oxygen scavenger solution and the other with a nitric oxide donor (sodium nitroprusside, SNP). The channels then guided these treatments to selected areas of the cell culture. We showed that microfluidics could target the specific region in the chip and modify microenvironmental gases in the cells. At the same time, the other cultural area remained unchanged. A simultaneous cellular response to hypoxia and nitric oxide was obtained after 100 min pumping with a flowrate of 1.6 μl/min. Preeclampsia (PE) is a pregnancy disorder where hypoxia plays a crucial role in the pathophysiology. To mimic a preeclampsia (PE) microenvironment, an oxygen scavenger solution was pumped through the microfluidic channels of a Myogel-coated microchip on which JEG-3 choriocarcinoma cells were cultured as a human trophoblast model for 24h. RNAseq data of the cells from the microchip showed gene expression differences and pathways that were affected by hypoxia; among those were MYC targets, E2F targets, G2-M checkpoint, and the unfolded protein response. Based on our data, the hypoxia created by the microchip caused significant transcriptional changes in JEG-3 cells.Vähentynyt hapen saanti aktivoi solujen hypoksian indusoivan tekijän (HIF) säätelyreitin. HIF on tärkeä fysiologisten vasteiden välittäjä akuutissa ja kroonisessa hypoksiassa. Perinteiset hypoksiakammiot, joita käytetään laajasti hypoksia tutkimuksessa, ovat hankalia ja vaativat suurta kaasunsyöttömäärää. Kaasujen voimakas diffuusio tekee mahdottomaksi säädellä paikallisesti kaasumaisia mikroympäristöjä hypoksiakammioissa. Tässä tutkimuksessa mikrofluidistisilla siruilla luotiin happigradientteja nano- ja mikromittakaavassa, toimimaan kaasumaisena mikroympäristönä soluviljelmille. Havaitsimme, että pumppaamalla hapenpoistoliuosta mikrofluidistisiin kanaviin hypoksiavaste lisääntyi mikrosirujärjestelmän soluissa. Samanaikainen solun kaasumainen mikroympäristö hypoksialle ja typpioksidille luotiin käyttämällä mikrofluidistisia siruja kahdella mikrokanavasarjalla. Toinen kanavista täytettiin hapenpoistoliuoksella ja toinen typpioksidin luovuttajalla (natriumnitroprussidi, SNP). Kanavat kohdensivat sitten kaasujen muutokset soluviljelmän valituille alueille. Osoitimme, että mikrofluidistiikan avulla voi kohdistaa muutokset tietylle alueelle sirussa ja muokata mikroympäristön kaasuja soluissa. Samaan aikaan muut viljelmän olosuhteet säilyivät ennallaan. Samanaikainen soluvaste hypoksialle ja typpioksidille saatiin 100 minuutin pumppauksen jälkeen virtausnopeudella 1.6 µl/min. Pre-eklampsia (PE) on raskaushäiriö, jonka patofysiologiassa hypoksialla on ratkaiseva rooli. Pre-eklampsian mikroympäristön jäljittelemiseksi hapenpoistoliuosta pumpattiin Myogeeli-pinnoitetun mikrosirun mikrofluidististen kanavien läpi, joissa JEG-3 koriokarsinoomasoluja viljeltiin ihmisen trofoblastimallina 24 tunnin ajan. Mikrosirun solujen RNAseq-profilointi osoitti hypoksian vaikuttavan geenien ilmentymistasoihin ja säätelyreitteihin; näiden joukossa olivat MYC-kohteet, E2F-kohteet, G2-M-tarkastuspiste ja vaste laskostumattomille proteiineille. Tulosten perusteella mikrosirun tuottama hypoksia aiheutti merkittäviä transkription muutoksia JEG-3-soluissa

A microfluidic oxygen sink to create a targeted cellular hypoxic microenvironment under ambient atmospheric conditions

Physiological oxygen levels within the tissue microenvironment are usually lower than 14%, in stem cell niches these levels can be as low as 0–1%. In cell cultures, such low oxygen levels are usually mimicked by altering the global culture environment either by O2 removal (vacuum or oxygen absorption) or by N2 supplementation for O2 replacement. To generate a targeted cellular hypoxic microenvironment under ambient atmospheric conditions, we characterised the ability of the dissolved oxygen-depleting sodium sulfite to generate an in-liquid oxygen sink. We utilised a microfluidic design to place the cultured cells in the vertical oxygen gradient and to physically separate the cells from the liquid. We demonstrate generation of a chemical in-liquid oxygen sink that modifies the surrounding O2 concentrations. O2 level control in the sink-generated hypoxia gradient is achievable by varying the thickness of the polydimethylsiloxane membrane. We show that intracellular hypoxia and hypoxia response element-dependentsignalling is instigated in cells exposed to the microfluidic in-liquid O2 sink-generated hypoxia gradient. Moreover, we show that microfluidic flow controls site-specific microenvironmental kinetics of the chemical O2 sink reaction, which enables generation of intermittent hypoxia/re-oxygenation cycles. The microfluidic O2 sink chip targets hypoxia to the cell culture microenvironment exposed to the microfluidic channel architecture solely by depleting O2 while other sites in the same culture well remain unaffected. Thus, responses of both hypoxic and bystander cells can be characterised. Moreover, control of microfluidic flow enables generation of intermittent hypoxia or hypoxia/re-oxygenation cycles. Statement of Significance: Specific manipulation of oxygen concentrations in cultured cells’ microenvironment is important when mimicking low-oxygen tissue conditions and pathologies such as tissue infarction or cancer. We utilised a sodium sulfite-based in-liquid chemical reaction to consume dissolved oxygen. When this liquid was pumped into a microfluidic channel, lowered oxygen levels could be measured outside the channel through a polydimethylsiloxane PDMS membrane allowing only for gaseous exchange. We then utilised this setup to deplete oxygen from the microenvironment of cultured cells, and showed that cells responded to hypoxia on molecular level. Our setup can be used for specifically removing oxygen from the cell culture microenvironment for experimental purposes and for generating a low oxygen environment that better mimics the cells’ original tissue environments.Peer reviewe

Transcriptomic Profiling of JEG-3 cells using human leiomyoma derived matrix

Peer reviewe