Bubble CPAP (BCPAP) is used in the neonatal intensive care unit (NICU) as a form of non-invasive ventilation and is commonly employed in neonates demonstrating respiratory distress. BCPAP may be used to avoid the need for intubation and mechanical ventilation thereby reducing lung injury and other morbidities as well as decrease hospital stay. PURPOSE: The purpose of this study is to retrospectively investigate the length of stay on bubble CPAP (BCPAP) considering gestational age, birth weight, and surfactant delivery in the neonatal population born at an urban tertiary high load level three (NICU). METHODS: A retrospective study using existing data from an urban tertiary high load level three NICU was completed. DATA ANALYSIS: Data analysis was performed using SPSS 16.0. Descriptive statistics were run for each variable. Contingency tables were run to determine if gestational age at birth, birth weight, and length of time on BCPAP had significance compared to surfactant delivery. Intercorrelations were run to determine if gestational age at birth, birth weight, and length of time on BCPAP had an effect on each other. Davis conventions were used to analyze the results. RESULTS: Descriptive statistics indicated the mean gestational age at birth to be 32.263 weeks, SD = +2.978, mean neonatal weight to be 1.899 kg, SD = +0.728, and mean length of time on BCPAP to be 124.430 hours, SD = +185.474. Contingency statistics showed a substantial association (reta = 0.562) between the gestational age at birth and surfactant delivery, a very strong association (reta = 1.000) between the birth weight and surfactant delivery, and a very strong association (reta = 0.914) between the length of time the neonate was on BCPAP and surfactant delivery. Pearson product-moment correlation coefficients showed gestational age at birth had a very strong positive association with birth weight (r = 0.811, p < 0.01) and a moderate negative association with length of time on BCPAP (r = -0.439, p < 0.01). Intercorrelations also showed birth weight had a moderate negative association with length of time on BCPAP (r = -0.306, p < 0.01). CONCLUSIONS: The neonate was less likely to receive surfactant if, their gestational age was older at birth, they had a heavier birth weight, and their length of time on BCPCP was shorter. The data also demonstrated that the older the neonate’s gestational age at birth and the heavier the neonatal birth weight equated to a shorter length of time on BCPAP. Lastly the data demonstrated that the heavier the neonate’s birth weight, the shorter length of time on BCPAP.

Objective: Ischemic spinal cord injury is a serious complication of aortic surgery. The mechanism underlying ischemic preconditioning (IPC) protection against spinal cord ischemia/reperfusion (I/R) injury is unclear. We investigated the role of spinal cord autoregulation in tolerance to spinal cord I/R injury induced by IPC. Although the extracellular signal-regulated kinases 1 and 2 (ERK1/2) are generally regarded as related to cell survival and proliferation, increasing evidence suggests that the role of the ERK1/2 pathway in I/R injury is contributory to inflammation. We investigated the effect of blocking ERK1/2 pathway to inhibit inflammation reaction in tolerance to spinal cord I/R injury. Methods: In the part 1 study, Sprague-Dawley rats were randomly assigned to 4 groups. IPC (P) group animals received IPC by temporary thoracic aortic occlusion (AO) with a 2-F Fogarty arterial embolectomy catheter for 3 min. I/R injury (I/R) group animals were treated with blood withdrawal and temporary AO for 12 min, and shed blood reinfusion at the end of the procedures. (P+I/R) group animals received IPC, followed by 5 min reperfusion, and then I/R procedures for 12 min. Sham (S) group animals received anesthesia and underwent surgical preparation only. Neurological functions were evaluated, and lumbar segments were harvested for histopathological examination. To evaluate the role of autoregulation in IPC, spinal cord blood flow and tissue oxygenation were continuously monitored throughout the procedure duration. In the part 2 study, spinal cord ischemia rats was induced by occluding the thoracic descending aorta with a balloon catheter introduced through a femoral artery, accompanied by concomitant exsanguinations. Rats in the control group were given dimethyl sulfoxide (vehicle) before undergoing spinal cord ischemia/reperfusion injury. In the U0126-treated group, rats were pretreated with an inhibitor of ERK1/2, U0126, to inhibit ERK1/2 phosphorylation. The sham rats underwent aortic catheterization without occlusion. Parameters, including neurologic status, neuronal survival, inflammatory cell infiltration, and interleukin-1£] production in the spinal cords, were compared between groups. Results: The Tarlov scores in the (I/R) group were significantly lower than those in the (S), (P), and (P+I/R) groups on days 1, 3, 5, and 7. The numbers of surviving motor neurons in the (S), (P), and (P+I/R) groups were significantly higher than those in the (I/R) group. The (P) group exhibited higher spinal cord blood flow and tissue oxygenation after reperfusion than the (S) group. The (P+I/R) group exhibited higher spinal cord blood flow and tissue oxygenation within the first 60 min after reperfusion than the (I/R) groups. In the part 2 study, early ERK1/2 phosphorylation was observed after injury in the control group, followed by abundant microglial accumulation in the infarct area and increased interleukin-1£] expression. In the U0126 group, U0126 treatment completely blocked ERK1/2 phosphorylation. Microglial activation and spinal cord interleukin-1£] levels were significantly reduced. Neuronal survival and functional performance were improved. Conclusions: IPC ameliorates spinal cord I/R injury in rats, probably mediated by triggering spinal cord autoregulation and improving local spinal cord blood flow and tissue oxygenation. The ERK1/2 pathway may play a noxious role in spinal cord ischemia/reperfusion injury by participating in inflammatory reactions and cytokine production. According to our findings, these concepts may be the new therapeutic targets in patients requiring aortic surgery.

We investigate the possibility of extracting accurate functional information such as local blood oxygenation level using multi-wavelength photoacoustic measurements. Photoacoustic microscope is utilized to acquire images of microvasculature in smallanimal skin. Owing to endogenous optical contrast, optical spectral information obtained from spectral photoacoustic measurements are successfully inverted to yield oxygenation level in blood. Analysis of error propagation from photoacoustic measurements to inverted quantities showed minimum inversion error in the optical wavelength region of 570-600 nm. To obtain accurate and vessel size independent blood oxygenation measurements, transducers with central frequency of more than 25 MHz are needed for the optical region of 570-600 nm used in this study. The effect of transducer focal position on accuracy of blood oxygenation level quantification was found to be negligible. To obtain accurate measurements in vivo, one needs to compensate for factors such as spectral dependent optical attenuation.

Given that pandemic swine flu outbreak led to substantial admission in intensive care unit, extracorporeal membrane oxygenation has been increasingly applied to those who suffered from H1N1 infection induced acute respiratory distress syndrome. This review is going to evaluate the effectiveness of using ECMO based on five related observational studies. The result, discussion and policy implication in Hong Kong are discussed. Since the ECMO system has been technological improved in recent years, there are less complications when applying ECMO. In view of evidence of reviewed studies, application of ECMO in Hong Kong can be considered as cost effective. And since only a few hospitals in Hong Kong can offer ECMO application, retrieval teams are needed to ensure safety transfer between hospitals. / published_or_final_version / Public Health / Master / Master of Public Health

Life on Earth could have existed already 3.8 Ga ago, and yet, more complex, multicellular life did not evolve until over three billion years later, about 700 Ma ago. Many have searched for the reason behind this apparent delay in evolution, and the dominating theories put the blame on the hostile Precambrian environment with low oxygen levels and sulphide-rich oceans. There are, however, doubts whether this would be the full explanation, and this thesis therefore focuses on a new hypothesis; the levels of the redox sensitive element arsenic increased in the oceans as a consequence of the change in weathering patterns that followed the upcome of free oxygen in the atmosphere at about 2.4 billion years ago. Given its toxicity, this could have had negative effects upon the life of the time. To test the hypothesis, 66 samples from drill cores coming from South Africa and Gabon with ages between 2.7 and 2.05 Ga were analysed for their elemental composition, and their arsenic content were compared with carbon isotope data from the same samples. These confirmed that a rise in arsenic concentration following the upcome of free oxygen in the atmosphere and the onset of oxidative weathering of continental sulphides. Arsenic, which is commonly found in sulphide minerals, was weathered together with the sulphide and delivered into the oceans, where it in the Palaeoproterozoic increased to over 600% compared to the older Archaean levels, at least locally. Iron had the strongest control over the arsenic levels in the anoxic (ferruginous and sulphidic) oceans, probably due to its ability to remove arsenic through adsorption. During oxygenated conditions, sulphur instead had the strongest influence upon arsenic, likely because of the lack of dissolved iron. The highest arsenic levels were found in samples recognised as coming from oxygenated conditions, although this might be due to the oxygenation state of arsenic affecting its solubility. Arsenic is toxic already at low doses, especially if the necessary arsenic detoxification systems had not yet evolved. However, the lack of correlation between arsenic and changes in δ13C indicated that the increase of arsenic did not affect the primary production between 2.7 and 2.05 Ga. Thus, whether arsenic could have affected the evolution of life during the Mesoproterozoic remains to be shown.

This study investigated the effects of hyperbaric oxygen (HBO) therapy on acute ankle injuries and determined if HBO therapy shortened time to recovery, decreased edema and pain, and increased range of motion and strength of the ankle. Subjects were randomly assigned to either an experimental (HBO) group (n = 4) or a control group (n = 4). All subjects received the same standardized physical therapy for lateral ankle sprains at the McGill Sport Medicine Clinic. The HBO group received 5 consecutive HBO treatments at 2.5 ATA for 90 minutes starting within 24 hours post injury. The control group received no HBO treatments. All subjects were evaluated by a physician within 24 hours of injury. All subjects suffered a second-degree lateral ankle sprain. Pain, range of motion, strength, volume displacement, and function were evaluated on the day of injury (Day 1), on Day 6 post injury, and on the day of return to play (Day RTP). There was no significant difference in time to return to play. However, the HBO group (25.5 +/- 11.6 days) did return 31% faster than the control group (36.8 +/- 19.4 days). There were no differences found between groups on the variables. There was a decrease in pain found over time (Day 1 was 57 mm, Day 6 was 18.5 mm, and Day RTP was 7 mm). The results of this study suggest that with treatment of HBO there is no effect on ankle sprains for return to play or improved function.

Noninvasive measurements of myocardial carboxymyoglobin levels (%MbCO) and oxygen tensions (PtO2) are difficult to obtain experimentally. We have developed a compartmental model which allows prediction of myocardial %MbCO levels and PtO2 for varied carbon monoxide (CO) exposures. The cardiac compartment in the model consists of vascular subcompartments which contain two tissue subcompartments varying in capillary density. Mass-balance equations for oxygen (O2) and CO are applied for all compartments. Myocardial oxygen consumption and blood flow are quantified from predictive formulas based on heart rate. Model predictions are validated with experimental data at normoxia, hypoxia, exercise and hyperoxia. CO exposures of varying concentration and time (short-high, long-low), CO rebreathing during 100% O2, and exposure during exercise is simulated. Results of the simulations demonstrate that during CO exposures and subsequent therapies, the temporal changes of %MbCO in the heart differ from those of carboxyhemoglobin levels (%HbCO). Analysis of correlation between %HbCO, %MbCO and PtO2 was done to understand myocardial injury due to CO hypoxia. This thesis demonstrates that the model is able to anticipate the uptake and distribution of CO in the human myocardium and thus can be used to estimate the extravascular burden (MbCO, PtO2 ) of CO on the human heart.

The overall aim of the present thesis was to study post-resuscitation care of cardiac arrest (CA) patients treated with target temperature management 33°C with a focus on evaluation of two prognostic tools: variations in cerebral venous saturation and acute magnetic resonance imaging (MRI) findings on the brain post-CA. An additional aim was to investigate patients’ neurological outcome and relatives’ experiences 6 months after the event. Paper I describes the cerebral oxygen saturation of blood obtained from a jugular bulb (SjvO2) catheter The results showed that patients with poor outcome tended to have higher SjvO2values,but this difference was only significant at 96 and108 hours post-CA. The main findings of Paper II were that patients with good outcome displayed a pathological pattern mainly in the frontal and parietal lobes on MRI of the brain. Patients with poor outcome had an extensive pathological pattern in several brain regions. Furthermore, very low apparent diffusion coefficient (ADC) values were associated with poor outcome regardless of brain region. Paper III investigated physical and cognitive function over time, between one month and 6 months post-CA, as well as d life satisfaction at 6 months. The results showed that impairment in physical and cognitive function is common in CA survivors but tends to decrease over time. Despite a severe illness, which has impaired the physical and cognitive functions, satisfaction with life as a whole was reported by 70% of CA survivors. In Paper IV, relatives described their experiences 6 months after a significant others CA. The analysis resulted in three themes reflecting relatives’ everyday life 6 months after the event: Difficulties managing a changed life situation, Feeling like I come second and Feeling new hope for the future. In conclusion, the results of the present thesis have increased our understanding of the two prognostic tools that were investigated; they have generated new and revealed aspects that should be taken into account during prognostication and assessing neurological outcome of this group of patients. The thesis has also shown that the healthcare needs to improve its routines for follow-ups and information provision to both patients and their relatives.

The overall objective of this work was to increase the knowledge regarding American hybrid grapes and wine-making techniques relevant to the State of Texas, specifically to investigate grape chemistry of hybrid grapes, to evaluate the effects of micro-oxygenation on wine chemistry, and to elucidate anti-cancer effects of wine compounds and extract in colon cancer cells in vitro. The methods used include HPLC-PDA-EIS-MSn and molecular bioassays. The American hybrid grapes, Black Spanish (Vitis aestivalis hybrid) and Blanc Du Bois (Vitis aestivalis hybrid), were compared to Cabernet Sauvignon and Merlot (Vitis vinifera) in their phytochemical composition. Total phenolics were similar in red grape varieties, but lower in white grapes. In Black Spanish grapes, anthocyanins and antioxidant capacity (ORAC) exhibited the highest values. Non-anthocyanin polyphenolics did not show qualitative differences in the four grape varieties. The presence of anthocyanins diglucosides was unique to Black Spanish grapes. The second experiment involved application of micro-oxygenation with oak inner staves to evaluate the effect of this new vinification technology on the stability of anthocyanins. Overall, anthocyanins exhibited significant decreases over time in the following order: control, wine with oak pieces, oak barrel, and micro-oxygenation. The anti-cancer effect of a combination of wine compounds, resveratrol/quercetin (RQ), and a polyphenolic extract from Black Spanish wine were investigated in colon cancer cells HT-29. RQ reduced the generation of reactive oxygen species (ROS), whereas the ORAC increased. RQ reduced cancer cell viability and proliferation, induced caspase-3-cleavage, and increased PARP-cleavage. Additionally, Sp1, Sp3, Sp4, and survivin were down-regulated at mRNA and protein levels. Furthermore, RQ decreased microRNA-27a (miR-27a) and induced ZBTB10, suggesting that RQ interactions with the miR-27a-ZBTB10-axis play a role in Sp down-regulation. Similar results were obtained for the wine extract. This work will provide valuable information regarding grape varieties, potential health benefits of wine, and wine production techniques to the wine industry in Texas and beyond.

When spontaneous breathing (SB) is allowed during mechanical ventilation (MV), atelectatic lung areas are recruited and oxygenation improves thereby. Whether unsupported SB at its natural pattern (without PEEP and at low pressure/small tidal volume) equally recruits and improves oxygenation, and if so by which mechanism, has not been studied. A porcine lung collapse model was designed to study this question. The cardiac output dependency of the pulmonary shunt was investigated with healthy lungs and with major shunt (during one-lung ventilation) and with SB, MV and continuous positive airway pressure (CPAP). The hypoxic pulmonary vasoconstriction (HPV) was blocked with sodium nitroprusside (SNP) to see whether HPV is the only mechanism available for ventilation/perfusion (VA/Q) matching during MV and SB. In all experiments, respiratory rate and tidal volume during MV were matched to SB. Oxygenation was assessed by serial blood gas measurements, recruitment by thoracic CTs; pulmonary shunt was assessed by multiple inert gas elimination or venous admixture. SB attained better oxygenation and lower pulmonary shunt compared with MV, although it did not recruit collapsed lung. Pulmonary shunt did not correlate with cardiac output during SB, whereas a correlation was found during MV and CPAP. With blocked HPV, pulmonary shunt was considerably lower during SB than MV. In conclusion, SB improves VA/Q matching as compared with MV, even when no recruitment occurs. In contrast to MV and CPAP, cardiac output has no major effect on pulmonary shunt during SB. The improved VA/Q matching during SB despite a blocked HPV might indicate the presence of a SB-specific mechanism that improves pulmonary blood flow redistribution towards ventilated lung regions independent of or supplementary to HPV.