Thesis--Copenhagen University. / Summary in Danish. Includes bibliographical references (p. 96-120).

Östersjön är idag det system med störst utbredning av syrefattiga eller syrefria bottnar i hela världen. Problemet har uppstått som följd av den massiva näringsbelastning från de kringliggande länderna som pågått sedan industrialiseringen intensifierades på 1900-talet. I och med omställningen till förnybar energi planeras framtida vindkraftsparker att byggas i Östersjön. Överflödig energi planeras att användas till havsbaserad vätgasproduktion som sedan forslas in till land med rör. Vid storskalig vätgasproduktion produceras som biprodukt enorma mängder syrgas vilket ger helt nya förutsättningar för artificiell syresättning av Östersjöns syrefria bottnar. Tre övergripande tekniker för att artificiellt syresätta bottenvatten med syrgas har identifierats på 21 platser runt om i världen: Downflow Bubble Contact System (DBCS), Side Stream Pumping System (SSPS) och Direct Oxygen Injection System (DOIS). Alla tre tekniker har med goda resultat förhöjt syrgaskoncentrationen i bottenvatten från hypoxiskt (< 2 mg/l) till oxiskt (> 2 mg/l). I flera fall har syresättningen bidragit till reduktion av näringsämnen och/eller utökat habitat för fiskar och bottendjur. En pilotanläggning i fjärden Slätbaken skulle ge bättre förståelse för hur ett system skulle kunna utformas i andra delar av Östersjön. En massbalansmodell konstruerades över Slätbaken och resultatet var att pilotanläggningen bör ha en kapacitet på 8 ton O2/dygn för att med säkerhet kunna höja syrgaskoncentrationen till > 4 mg/l. Detta skulle ge en lämplig säkerhetsmarginal för den lokala bottennära eller bottenlevande faunan med avseende på syrgashalt. / As of today, the Baltic Sea is the system with the globally largest expansion of hypoxic or anoxic bottom waters, so-called “dead zones”. It is a consequence of the massive load of nutrients from the surrounding countries that started with the intensified industrialization in the start of the 20th century. With the transformation towards renewable energy, wind parks are planned to be built in the Baltic Sea on a substantial scale. Thereby, superfluous energy is planned to be used for sea-based production of hydrogen gas that can be piped to land. Large scale hydrogen gas production would generate enormous amounts of oxygen gas as a byproduct, which gives a theoretical opportunity to artificially oxygenate the dead zones of the Baltic Sea. Three main techniques to artificially oxygenate bottom waters were identified in 21 freshwater systems around the world: Downflow Bubble Contact System (DBCS), Side Stream Pumping System (SSPS) and Direct Oxygen Injection System (DOIS). All three techniques have successfully raised the concentration of dissolved oxygen from hypoxic (< 2 mg/l) to oxic (> 2 mg/l). In many cases, the oxygenation contributed to reduction of dissolved nutrients in the waters and/or enlarged habitats for fish and benthic fauna. A pilot plant for oxygenation in the bay Slätbaken would contribute to better understanding of how a future oxygenation system could be constructed in other parts of the Baltic Sea. A mass balance model was constructed, representing oxygen content and transport in Slätbaken. Results indicated that establishing a pilot plant would need a capacity of 8 tons O2/day to guarantee a dissolved oxygen concentration of > 4 mg/l, which would provide local fauna with a suitable safety margin regarding dissolved oxygen concentrations.

In resting muscle, blood flow is regulated to meet the demand for O2 by the tissue. A modified ischemia (I)/reperfusion(R) investigation was systematically run and PISFO2, PaO2, Q and VO2 were observed. Twenty-nine spinotrapezius muscles from male Sprague-Dawley rats (284±20 grams) were surgically exteriorized for intravital microscopy to test a model relating blood flow, O2 supply and O2 demand. The model can aid in the understanding of the regulation of tissue PO2. The interstitial PO2 (PISFO2) and perivascular PO2 (PaO2) measurements were made using phosphorescence quenching microscopy (PQM). O2 consumption (VO2) values were obtained with a quasi-continuous, flash-synchronized, pressurized airbag to initiate ischemia and sample the rate of O¬2 change (dPO2/dt). Centerline red blood cell velocity was measured with an Optical Doppler Velocimeter and converted to flow using vessel diameter. 5-, 15-, 30-, 60-, 300- and 600-second ischemic durations were used to observe changes in PISFO2, Q, and VO2. A critical point was observed following 30 seconds of (I) where dPISFO2/dt during recovery was the fastest (4.25±0.72 mmHg/s) and was 1.00±0.16 mmHg/s following 600 seconds. Flow recovery, dQ/dt, peaked to 3.88±0.64 (µl•min-1)/s after 60 seconds of (I) but significantly dropped to 2.83±0.55 (µl•min-1)/s following 300 seconds of (I) but increased to 2.92±0.45 (µl•min-1)/s following 600 seconds. This gives evidence to a no-reflow phenomenon occurring in the extended periods of ischemia. A peak in VO¬2 to 309.2±45.0 nl O2/cm3•s with a time course of 160 seconds occurred following 600 seconds of ischemia. As the ischemic duration decreased, the time course and peak VO2 also decreased. VO2 following 300 seconds of (I) was significantly higher than 5-60 seconds of (I) (p <0.05) but was not significantly different from 600 seconds of (I). The information collected during the Q and VO2 studies can be incorporated into a factor, M, that relates VO2, Q and ∆PO2. M calculated for the recovery of 5- through 60-second (I) groups reasonably relates the three variables due to consistency and little variability. However, recovery in 600- and especially 300-second (I) groups showed higher variability in M which requires more consideration.

A fairly large portion of patients receiving surgical or intensive care will need mechanical ventilation at some point. The potential ventilator-induced lung injury (VILI) is thus of interest. One of the main causal factors in VILI is the cyclic energy shifts, i.e. tidal volumes, in the lung during mechanical ventilation. The problem can be approached in two ways. Firstly, one can utilize apneic oxygenation and thus not cause any tidal injuries at all. Secondly, and more traditionally, one can simply lower the tidal volumes and respiratory rates used. The following describes a series of animal experiments exploring these options. In the first two papers, I explored and improved upon the methodology of apneic oxygenation. There is a generally held belief that it is only possible to perform apneic oxygenation by prior denitrogenation and by using 100% oxygen during the apnea. As 100% oxygen is toxic, this has prevented apneic oxygenation from more widespread use. The first paper proves that it is indeed possible to perform apneic oxygenation with less than 100% oxygen. I also calculated the alveolar nitrogen concentration which would conversely give the alveolar oxygen concentration. The second paper addresses the second large limitation of apneic oxygenation, i.e. hypercapnia. Using a high dose infusion of tris(hydroxymethyl)aminomethane (THAM) buffer, a pH &gt; 7.2 could be maintained during apneic oxygenation for more than 4.5 hours. In the last two papers, THAM’s properties as a proton acceptor are explored during respiratory acidosis caused by very low volume ventilation. In paper III, I found that THAM does not, in the long term, affect pH in respiratory acidosis after stopping the THAM infusion. It does, however, lower PVR, even though the PaCO2 of THAM-treated animals had rebounded to levels higher than that of the controls. In the last experiment, I used volumetric capnography to confirm our hypothesis that carbon dioxide elimination through the lungs was lower during the THAM infusion. Again, the PaCO2 rebounded after the THAM infusion had stopped and I concluded that renal elimination of protonated THAM was not sufficient.

A bactéria Lactococcus lactis subsp. lactis CECT-4434 foi empregada para investigar o efeito da composição do meio de cultivo na produção biotecnológica de biossurfactante e, adicionalmente bacteriocina. Utilizou-se resíduos agroindustriais, tais como soro de leite e vinhaça de uva, para formular meios de cultivos mais econômicos e naturais, suplementados sacarose e extrato de levedura. Um planejamento fatorial fracionado 24, com adição de três ensaios nos pontos centrais foi empregado para avaliar a influência destas variáveis. A produção de biossurfactante foi influenciada positivamente pela concentração soro de leite, onde 15 % deste demonstrou melhor resultado reduzindo a tensão superficial em cerca de 18,1 mN/m, alcançando produção máxima de biossurfactante equivalente em surfactina de 11,02 mg/L. Em relação à síntese de bacteriocina, a fonte de carbono adicional (sacarose) interferiu de forma antagonista, ou seja, quanto menor a concentração de sacarose, maior a síntese de bacteriocina (com aumento da zona de inibição em 14,2% contra Staphylococcus aureus CECT-239). Observou-se que o ensaio conduzido em biorreator, sob microaeração com 5% de oxigênio dissolvido, promoveu maior produção de biossurfactante (11,6 mg/L) quando comparados aos estudos conduzidos com maior concentração de oxigênio entre 30 a 100%, com produção em média de 2,3 mg/mL. Destaca-se que nenhum estudo da influência do oxigênio dissolvido, principalmente em microaerofilia, para a produção de biossurfactante por bactérias láticas já havia sido realizado. Ademais, o biossurfactante produzido se mostrou altamente estável frente a valores extremos de pH e temperatura, além de demonstrar notável propriedade antimicrobiana e antiadesiva, inibindo Listeria monocytogenes NADC 2045 e Salmonella entérica<i/> CECT-724 em mais de 90%. / Lactococcus lactis subsp. lactis CECT-4434 was used to investigate the effect of the composition of the culture media on the biotechnological production of biosurfactant and bacteriocin additionally. Agroindustrial residues, such as whey and grape vinasse, were used to formulate more economical and natural culture media, supplemented with sucrose and yeast extract. A fractional factorial design 24, with addition of three runs at the central points was used to evaluate the influence of these variables. The biosurfactant production was positively influenced by the concentration of whey, where 15% showed a better result reducing the surface tension by 18.1 mN/m, reaching a maximum production of biosurfactant equivalent in surfactin of 11.02 mg/L. In relation to bacteriocin synthesis, the sucrose interfered in an antagonistic way, that is, the lower the sucrose concentration, the greater the bacteriocin synthesis (with an increase in the zone of inhibition in 14.2% against Staphylococcus aureus CECT-239). It was observed that the bioreactor conducted under microaeration with 5% dissolved oxygen promoted a higher biosurfactant production (11.6 mg/L) when compared to studies conducted with a higher concentration of oxygen between 30 and 100%, with production on average 2.3 mg/mL. It is noteworthy that no study of the influence of dissolved oxygen, mainly in microaerophilic, for the biosurfactant production by lactic acid bacteria had already been carried out. In addition, the biosurfactant produced proved to be highly stable against extreme values of pH and temperature, and demonstrated remarkable antimicrobial and antiadhesive properties, inhibiting Listeria monocytogenes NADC 2045 and Salmonella entérica CECT-724 in more than 90%.

Assegurar o bem-estar dos animais de laboratório e evitar a dor e o sofrimento desnecessários são as principais considerações na experimentação. Por isso, a investigação em busca de novos protocolos anestésicos que garantam um mínimo ou nulo desconforto dos animais tem-se convertido num tema prioritário. Neste estudo realizou-se a comparação do efeito da combinação de xilazina (X) e ketamina (K) com acepromazina (A) e opióides [metadona (Me), morfina (Mo) e tramadol (T)] com a finalidade de avaliar sua influência nos parâmetros fisiológicos de ratos de laboratório, para ambos os sexos, bem como seu poder analgésico e o efeito da oxigenação sobre os mesmos. A associação XKA para ratos machos e fêmeas e a associação XKMe para fêmeas foram as mais seguras e eficazes para procedimentos anestésicos. Porém, os resultados do teste de formalina com a medição da vocalização ultrassônica (VUS) sugerem que o protocolo de XKA tem um poder analgésico baixo, não sendo indicado para procedimentos que possam gerar dor moderada ou severa. Todas as associações anestésicas tiveram efeitos importantes como diurese, manutenção dos olhos abertos e hiperglicemia, os quais devem ser considerados quando possam influenciar nos resultados experimentais. Também, se conseguiu demonstrar que a oxigenação melhora a saturação de oxigênio (SO2) e os valores da pressão parcial de oxigênio (pO2) confirmando que sua utilização deveria ser sempre parte dos procedimentos experimentais com anestesia injetável para evitar a hipoxemia. Não obstante, observou-se uma acidose respiratória por aumento da pressão parcial do CO2 (pCO2) e diminuição do pH, cuja causa se relacionou à hipoventilação por depressão respiratória e acúmulo de CO2 durante o transcorrer da anestesia. Tal situação demonstra a necessidade de oxigenar os animais desde a indução da anestesia e de administrar medicamentos para reverter a depressão respiratória como a naloxona, bem como utilizar animais que não apresentem nenhum tipo de comprometimento respiratório. Portanto, a inclusão de analgesia e a oxigenação nos protocolos anestésicos injetáveis devem ser utilizadas de forma rotineira garantindo a mínima presença de dor e, com isso, resultados mais confiáveis nos procedimentos experimentais. / Ensuring the wellbeing of laboratory animals and avoiding unnecessary pain and suffering is one of the main considerations in experimentation. Therefore, the investigation of new anesthetic protocols that guarantee a minimum or null discomfort of the animals has become a priority theme. In this study, it was made an evaluation of the effect of the combination of xylazine (X) and ketamine (K) with acepromazina (A) and opioids [methadone (Me), morphine (Mo) e tramadol (T)] with the purpose of comparing their influence on the physiological parameters of laboratory rats, for both sexes, and evaluating their analgesic power and the effect of the oxygenation on them. The XKA protocol for male and females rats and the XKMe protocol for females were the safest and most effective for anesthetic procedures. However, the results of the formalin test with the measurement of the ultrasonic vocalization (VUS) suggest that the XKA protocol had a low analgesic power, and it is not indicated for procedures that can generate moderate or severe pain. All anesthetic protocols had important effects as diuresis, maintenance of open eyes, and hyperglycemia; these effects should be considered when they could influence in the experimental results. It was demonstrated that oxygenation improves oxygen saturation (SO2) and oxygen partial pressure (pO2) confirming that its use should be considered in the experimental procedures with injectable anesthesia to avoid hypoxemia. Nevertheless, a respiratory acidosis was observed due to the increase in partial pressure of CO2 (pCO2) and the decrease in pH, that could be caused for the hypoventilation due to respiratory depression and CO2 accumulation during the course of anesthesia. This leads to consider the need to pre-oxygenate animals from induction, to use drugs to reverse respiratory depression such as naloxone, and to work with animals that are not respiratory compromised. Therefore the inclusion of analgesia and oxygenation in anesthesia protocols should begin to be used routinely ensuring minimal presence of pain and thus more reliable results in the experimental procedures.

Over 26 million Americans suffer from pulmonary disease, resulting in more than 150,000 deaths annually. Lung transplantation remains the only definitive treatment for many patients, but has meager survival rates and only approximately 1,700 of the 2,200 patients added to the lung transplant wait list each year are transplanted. Extracorporeal gas exchangers have been used as an alternative to mechanical ventilation in acute respiratory failure and as a bridge to transplantation in chronic respiratory failure. Current gas exchangers are limited by their high resistance and low biocompatibility that lead to patient complications and device clot formation. Therefore, there exists a dire need for improved devices that can act as destination therapy. To accomplish the goal of destination therapy, this dissertation discusses three studies that were performed to pave the way. First, I examined clot formation and failure patterns of two common clinical devices (Maquet’s CardioHelp (CH) and Quadrox (Qx)) to further our understanding of their limitations with respect to long-term support. Overall, it was demonstrated that the Qx devices fail earlier and more frequently than CH devices and result in a significantly greater reduction in platelet count, and that a four-inlet approach is beneficial. Next, I determined the optimal sweep gas nitric oxide (NO) concentration that minimizes platelet binding and activation while ensuring that blood methemoglobin (metHb) concentrations increase less than 5%. Miniature artificial lungs were attached to rabbits in a pumped veno-venous configuration and run for 4 h with NO added to the sweep gases in concentrations of 0, 100, 250, and 500 ppm (n=8 ea.). 100 ppm significantly reduced the amount of platelet consumption (p < 0.05), reduced platelet activation as measured by soluble p-selectin (p < 0.05), and had negligible increases in metHb and will thus be used in future experiments. Last, I tested the Pulmonary Assist Device (PAD) which was designed for long term use as a bridge to transplantation and destination therapy. Benchtop experiments were performed that confirmed that it meets our design and performance goals. From here, we are equipped to commence with 30-day PAD testing in sheep.

Assegurar o bem-estar dos animais de laboratório e evitar a dor e o sofrimento desnecessários são as principais considerações na experimentação. Por isso, a investigação em busca de novos protocolos anestésicos que garantam um mínimo ou nulo desconforto dos animais tem-se convertido num tema prioritário. Neste estudo realizou-se a comparação do efeito da combinação de xilazina (X) e ketamina (K) com acepromazina (A) e opióides [metadona (Me), morfina (Mo) e tramadol (T)] com a finalidade de avaliar sua influência nos parâmetros fisiológicos de ratos de laboratório, para ambos os sexos, bem como seu poder analgésico e o efeito da oxigenação sobre os mesmos. A associação XKA para ratos machos e fêmeas e a associação XKMe para fêmeas foram as mais seguras e eficazes para procedimentos anestésicos. Porém, os resultados do teste de formalina com a medição da vocalização ultrassônica (VUS) sugerem que o protocolo de XKA tem um poder analgésico baixo, não sendo indicado para procedimentos que possam gerar dor moderada ou severa. Todas as associações anestésicas tiveram efeitos importantes como diurese, manutenção dos olhos abertos e hiperglicemia, os quais devem ser considerados quando possam influenciar nos resultados experimentais. Também, se conseguiu demonstrar que a oxigenação melhora a saturação de oxigênio (SO2) e os valores da pressão parcial de oxigênio (pO2) confirmando que sua utilização deveria ser sempre parte dos procedimentos experimentais com anestesia injetável para evitar a hipoxemia. Não obstante, observou-se uma acidose respiratória por aumento da pressão parcial do CO2 (pCO2) e diminuição do pH, cuja causa se relacionou à hipoventilação por depressão respiratória e acúmulo de CO2 durante o transcorrer da anestesia. Tal situação demonstra a necessidade de oxigenar os animais desde a indução da anestesia e de administrar medicamentos para reverter a depressão respiratória como a naloxona, bem como utilizar animais que não apresentem nenhum tipo de comprometimento respiratório. Portanto, a inclusão de analgesia e a oxigenação nos protocolos anestésicos injetáveis devem ser utilizadas de forma rotineira garantindo a mínima presença de dor e, com isso, resultados mais confiáveis nos procedimentos experimentais. / Ensuring the wellbeing of laboratory animals and avoiding unnecessary pain and suffering is one of the main considerations in experimentation. Therefore, the investigation of new anesthetic protocols that guarantee a minimum or null discomfort of the animals has become a priority theme. In this study, it was made an evaluation of the effect of the combination of xylazine (X) and ketamine (K) with acepromazina (A) and opioids [methadone (Me), morphine (Mo) e tramadol (T)] with the purpose of comparing their influence on the physiological parameters of laboratory rats, for both sexes, and evaluating their analgesic power and the effect of the oxygenation on them. The XKA protocol for male and females rats and the XKMe protocol for females were the safest and most effective for anesthetic procedures. However, the results of the formalin test with the measurement of the ultrasonic vocalization (VUS) suggest that the XKA protocol had a low analgesic power, and it is not indicated for procedures that can generate moderate or severe pain. All anesthetic protocols had important effects as diuresis, maintenance of open eyes, and hyperglycemia; these effects should be considered when they could influence in the experimental results. It was demonstrated that oxygenation improves oxygen saturation (SO2) and oxygen partial pressure (pO2) confirming that its use should be considered in the experimental procedures with injectable anesthesia to avoid hypoxemia. Nevertheless, a respiratory acidosis was observed due to the increase in partial pressure of CO2 (pCO2) and the decrease in pH, that could be caused for the hypoventilation due to respiratory depression and CO2 accumulation during the course of anesthesia. This leads to consider the need to pre-oxygenate animals from induction, to use drugs to reverse respiratory depression such as naloxone, and to work with animals that are not respiratory compromised. Therefore the inclusion of analgesia and oxygenation in anesthesia protocols should begin to be used routinely ensuring minimal presence of pain and thus more reliable results in the experimental procedures.

A bactéria Lactococcus lactis subsp. lactis CECT-4434 foi empregada para investigar o efeito da composição do meio de cultivo na produção biotecnológica de biossurfactante e, adicionalmente bacteriocina. Utilizou-se resíduos agroindustriais, tais como soro de leite e vinhaça de uva, para formular meios de cultivos mais econômicos e naturais, suplementados sacarose e extrato de levedura. Um planejamento fatorial fracionado 24, com adição de três ensaios nos pontos centrais foi empregado para avaliar a influência destas variáveis. A produção de biossurfactante foi influenciada positivamente pela concentração soro de leite, onde 15 % deste demonstrou melhor resultado reduzindo a tensão superficial em cerca de 18,1 mN/m, alcançando produção máxima de biossurfactante equivalente em surfactina de 11,02 mg/L. Em relação à síntese de bacteriocina, a fonte de carbono adicional (sacarose) interferiu de forma antagonista, ou seja, quanto menor a concentração de sacarose, maior a síntese de bacteriocina (com aumento da zona de inibição em 14,2% contra Staphylococcus aureus CECT-239). Observou-se que o ensaio conduzido em biorreator, sob microaeração com 5% de oxigênio dissolvido, promoveu maior produção de biossurfactante (11,6 mg/L) quando comparados aos estudos conduzidos com maior concentração de oxigênio entre 30 a 100%, com produção em média de 2,3 mg/mL. Destaca-se que nenhum estudo da influência do oxigênio dissolvido, principalmente em microaerofilia, para a produção de biossurfactante por bactérias láticas já havia sido realizado. Ademais, o biossurfactante produzido se mostrou altamente estável frente a valores extremos de pH e temperatura, além de demonstrar notável propriedade antimicrobiana e antiadesiva, inibindo Listeria monocytogenes NADC 2045 e Salmonella entérica<i/> CECT-724 em mais de 90%. / Lactococcus lactis subsp. lactis CECT-4434 was used to investigate the effect of the composition of the culture media on the biotechnological production of biosurfactant and bacteriocin additionally. Agroindustrial residues, such as whey and grape vinasse, were used to formulate more economical and natural culture media, supplemented with sucrose and yeast extract. A fractional factorial design 24, with addition of three runs at the central points was used to evaluate the influence of these variables. The biosurfactant production was positively influenced by the concentration of whey, where 15% showed a better result reducing the surface tension by 18.1 mN/m, reaching a maximum production of biosurfactant equivalent in surfactin of 11.02 mg/L. In relation to bacteriocin synthesis, the sucrose interfered in an antagonistic way, that is, the lower the sucrose concentration, the greater the bacteriocin synthesis (with an increase in the zone of inhibition in 14.2% against Staphylococcus aureus CECT-239). It was observed that the bioreactor conducted under microaeration with 5% dissolved oxygen promoted a higher biosurfactant production (11.6 mg/L) when compared to studies conducted with a higher concentration of oxygen between 30 and 100%, with production on average 2.3 mg/mL. It is noteworthy that no study of the influence of dissolved oxygen, mainly in microaerophilic, for the biosurfactant production by lactic acid bacteria had already been carried out. In addition, the biosurfactant produced proved to be highly stable against extreme values of pH and temperature, and demonstrated remarkable antimicrobial and antiadhesive properties, inhibiting Listeria monocytogenes NADC 2045 and Salmonella entérica CECT-724 in more than 90%.

Despite significant advances in medical imaging technologies, there currently exist no tools to effectively assist healthcare professionals during surgical procedures. In turn, procedures remain subjective and dependent on experience, resulting in avoidable failure and significant quality of care disparities across hospitals. Optical techniques are gaining popularity in clinical research because they are low cost, non-invasive, portable, and can retrieve both fluorescence and endogenous contrast information, providing physiological information relative to perfusion, oxygenation, metabolism, hydration, and sub-cellular content. Near-infrared (NIR) light is especially well suited for biological tissue and does not cause tissue damage from ionizing radiation or heat. My dissertation has been focused on developing rapid imaging techniques for mapping endogenous tissue constituents to aid surgical guidance. These techniques allow, for the first time, video-rate quantitative acquisition over a large field of view (> 100 cm2) in widefield and endoscopic implementations. The optical system analysis has been focused on the spatial-frequency domain for its ease of quantitative measurements over large fields of view and for its recent development in real-time acquisition, single snapshot of optical properties (SSOP) imaging. Using these methods, this dissertation provides novel improvements and implementations to SSOP, including both widefield and endoscopic instrumentations capable of video-rate acquisition of optical properties and sample surface profile maps. In turn, these measures generate profile-corrected maps of hemoglobin concentration that are highly beneficial for perfusion and overall tissue viability. Also utilizing optical property maps, a novel technique for quantitative fluorescence imaging was also demonstrated, showing large improvement over standard and ratiometric methods. To enable real-time feedback, rapid processing algorithms were designed using lookup tables that provide a 100x improvement in processing speed. Finally, these techniques were demonstrated in vivo to investigate their ability for early detection of tissue failure due to ischemia. Both pre-clinical studies show endogenous contrast imaging can provide early measures of future tissue viability. The goal of this work has been to provide the foundation for real-time imaging systems that provide tissue constituent quantification for tissue viability assessments. / 2018-01-09T00:00:00Z