Critical leg ischaemia with tissue loss : a challenge for the vascular surgeon

There is a widespread reporting habit of combining the outcomes for patients with rest pain (Fontaine III) and tissue loss (Fontaine IV) under the single category of critical leg ischaemia (CLI). This study focused on patients with ischaemic tissue loss treated with infrainguinal bypass surgery (IBS). All patients included in the study were treated at Helsinki University Central Hospital in 2000-2007. First, ulcer healing time after IBS and factors influencing healing time were prospectively assessed in 2 studies including 148 and 110 patients, respectively. Second,the results of redo IBS were retrospectively evaluated in 593 patients undergoing primary IBS for CLI with tissue loss . Third,long-term outcome were retrospectively analysed in 636 patients who underwent IBS for CLI with tissue loss . Fourth, the outcome of IBS was retrospectively compared with endovascular treatment (PTA) of the infrapopliteal arteries in 1023 CLI patients. Fifth, the influence multidrug resistant Pseudomans aeruginosa (MDR Pa) bacteria contamination in CLI patients treated with IBS was retropectively assessed. Sixty-four patients with positive MDR Pa -culture were matched with 64 MDR Pa - negative controls. Complete ulcer healing rate, including the ischemic ulcers and incisional wounds, was 40% at 6 months after IBS and 75% at one year. Diabetes was a risk factor for prolonged complete ulcer healing time. Ischaemic tissue lesions located in mid-and hindfoot healed poorly. At one year after IBS 50% of the patients were alive with salvaged leg and completely healed ulcers. The absence of gap between tertiary graft patency and leg salvage rates indicates the importance of a patent infrainguinal graft to save a leg with ischaemic tissue loss. Long-term survival for patients with ischaemic tissue loss was poor, 38% at 5 years. Only 30% of the patients were alive without amputation at 5 years. Several of the patient comorbidities increased independently the mortality risk; coronary artery disease, renal insufficiency, chronic obstructive lung disease and high age. When both PTA and bypass is feasible, infrapopliteal PTA as a first-line strategy is expected to achieve similar long-term results to bypass surgery in CLI when redo surgery is actively utilized. MDR Pa in a patient with CLI should be considered as a serious event with increased risk of early major amputation or death. Conclusion: Despite a successful infrainguinal bypass healing of the ischaemic ulcers and incisional wounds ulcer healing is a slow process especially in diabetics. Bypass surgery and PTA improve the outcome of the ischaemic leg but the mortality rate of the patients is high due to their severe comorbidities.

Factors affecting perceptions of corporate social responsibility implementation: an emphasis on values

This dissertation is a broad study of factors affecting perceptions of CSR issues in multiple stakeholder realms, the main purpose being to determine the effects of the values of individuals on their perceptions regarding CSR. It examines perceptions of CSR both at the emic (observing individuals and stakeholders) and etic levels (conducting cross-cultural comparison) through a descriptive-empirical research strategy. The dissertation is based on quantitative interview data among Chinese, Finnish and US stakeholder groups of industry companies (with an emphasis on the forest industries) and consists of four published articles and two submitted manuscripts. Theoretically, this dissertation provides a valuable and unique philosophical and intellectual perspective on the contemporary study of CSR `The Harmony Approach to CSR'. Empirically, this dissertation does values assessment and CSR evaluation of a wide variety of business activities covering CSR reporting, business ethics, and three dimensions of CSR performance. From the multi-stakeholder perspective, this dissertation use survey methods to examine the perceptions and stakeholder salience in the context of CSR by describing, comparing the differences between demographic factors as well as hypothetical drivers behind perceptions. The results of study suggest that the CSR objective of a corporation's top management should be to manage the divergent and conflicting interests of multiple stakeholders, taking others than key stakeholders into account as well. The importance of values as a driver of ethical behaviour and decision-making has been generally recognized. This dissertation provides more empirical proof of this theory by highlighting the effects of values on CSR perceptions. It suggests that since the way to encourage responsible behaviour and develop CSR is to develop individual values and cultivate their virtues, it is time to invoke the critical role of moral (ethics) education. The specific studies of China and comparison between Finland and the US contribute to a common understanding of the emerging CSR issues, problems and opportunities for the future of sustainability. The similarities among these countries can enhance international cooperation, while the differences will open up opportunities and diversified solutions for CSR in local conditions.

High-risk patients and high-risk grafts in infrainguinal bypass for critical limb ischaemia

The main purpose of revascularization procedures for critical limb ischaemia (CLI) is to preserve the leg and sustain the patient s ambulatory status. Other goals are ischaemic pain relief and healing of ischaemic ulcers. Patients with CLI are usually old and have several comorbidities affecting the outcome. Revascularization for CLI is meaningless unless both life and limb are preserved. Therefore, the knowledge of both patient- and bypass-related risk factors is of paramount importance in clinical decision-making, patient selection and resource allocation. The aim of this study was to identify patient- and graft-related predictors of impaired outcome after infrainguinal bypass for CLI. The purpose was to assess the outcome of high-risk patients undergoing infrainguinal bypass and to evaluate the usefulness of specific risk scoring methods. The results of bypasses in the absence of optimal vein graft material were also evaluated, and the feasibility of the new method of scaffolding suboptimal vein grafts was assessed. The results of this study showed that renal insufficiency - not only renal failure but also moderate impairment in renal function - seems to be a significant risk factor for both limb loss and death after infrainguinal bypass in patients with CLI. Low estimated GFR (PIENEMPI KUIN 30 ml/min/1.73 m2) is a strong independent marker of poor prognosis. Furthermore, estimated GFR is a more accurate predictor of survival and leg salvage after infrainguinal bypass in CLI patients than serum creatinine level alone. We also found out that the life expectancy of octogenarians with CLI is short. In this patient group endovascular revascularization is associated with a better outcome than bypass in terms of survival, leg salvage and amputation-free survival especially in presence of coronary artery disease. This study was the first one to demonstrate that Finnvasc and modified Prevent III risk scoring methods both predict the long-term outcome of patients undergoing both surgical and endovascular infrainguinal revascularization for CLI. Both risk scoring methods are easy to use and might be helpful in clinical practice as an aid in preoperative patient selection and decision-making. Similarly than in previous studies, we found out that a single-segment great saphenous vein graft is superior to any other autologous vein graft in terms of mid-term patency and leg salvage. However, if optimal vein graft is lacking, arm vein conduits are superior to prosthetic grafts especially in infrapopliteal bypasses for CLI. We studied also the new method of scaffolding suboptimal quality vein grafts and found out that this method may enable the use of vein grafts of compromised quality otherwise unsuitable for bypass grafting. The remarkable finding was that patients with the combination of high operative risk due to severe comorbidities and risk graft have extremely poor survival, suggesting that only relatively fit patients should undergo complex bypasses with risk grafts. The results of this study can be used in clinical practice as an aid in preoperative patient selection and decision-making. In the future, the need of vascular surgery will increase significantly as the elderly and diabetic population increases, which emphasises the importance of focusing on those patients that will gain benefit from infrainguinal bypass. Therefore, the individual risk of the patient, ambulatory status, outcome expectations, the risk of bypass procedure as well as technical factors such as the suitability of outflow anatomy and the available vein material should all be assessed and taken into consideration when deciding on the best revascularization strategy.

Microbiological characterisation of soils : Evaluation of some critical steps in data collection and experimental design

The study of soil microbiota and their activities is central to the understanding of many ecosystem processes such as decomposition and nutrient cycling. The collection of microbiological data from soils generally involves several sequential steps of sampling, pretreatment and laboratory measurements. The reliability of results is dependent on reliable methods in every step. The aim of this thesis was to critically evaluate some central methods and procedures used in soil microbiological studies in order to increase our understanding of the factors that affect the measurement results and to provide guidance and new approaches for the design of experiments. The thesis focuses on four major themes: 1) soil microbiological heterogeneity and sampling, 2) storage of soil samples, 3) DNA extraction from soil, and 4) quantification of specific microbial groups by the most-probable-number (MPN) procedure. Soil heterogeneity and sampling are discussed as a single theme because knowledge on spatial (horizontal and vertical) and temporal variation is crucial when designing sampling procedures. Comparison of adjacent forest, meadow and cropped field plots showed that land use has a strong impact on the degree of horizontal variation of soil enzyme activities and bacterial community structure. However, regardless of the land use, the variation of microbiological characteristics appeared not to have predictable spatial structure at 0.5-10 m. Temporal and soil depth-related patterns were studied in relation to plant growth in cropped soil. The results showed that most enzyme activities and microbial biomass have a clear decreasing trend in the top 40 cm soil profile and a temporal pattern during the growing season. A new procedure for sampling of soil microbiological characteristics based on stratified sampling and pre-characterisation of samples was developed. A practical example demonstrated the potential of the new procedure to reduce the analysis efforts involved in laborious microbiological measurements without loss of precision. The investigation of storage of soil samples revealed that freezing (-20 °C) of small sample aliquots retains the activity of hydrolytic enzymes and the structure of the bacterial community in different soil matrices relatively well whereas air-drying cannot be recommended as a storage method for soil microbiological properties due to large reductions in activity. Freezing below -70 °C was the preferred method of storage for samples with high organic matter content. Comparison of different direct DNA extraction methods showed that the cell lysis treatment has a strong impact on the molecular size of DNA obtained and on the bacterial community structure detected. An improved MPN method for the enumeration of soil naphthalene degraders was introduced as an alternative to more complex MPN protocols or the DNA-based quantification approach. The main advantage of the new method is the simple protocol and the possibility to analyse a large number of samples and replicates simultaneously.

GATA Factors Regulate Inner Ear Development and Midbrain Neurogenesis

The zinc-finger transcription factors GATA2 and GATA3 in vertebrates belong to the six-member family that are essential regulators in the development of various organs. The aim of this study was to gain new information of the roles of GATA2 and GATA3 in inner ear morphogenesis and of the function of GATA2 in neuronal fate specification in the midbrain using genetically modified mouse and chicken embryos as models. A century ago the stepwise process of inner ear epithelial morphogenesis was described, but the molecular players regulating the cellular differentiation of the otic epithelium are still not fully resolved. This study provided novel data on GATA factor roles in several developmental processes during otic development. The expression analysis in chicken suggested that GATA2 and GATA3 possess redundant roles during otic cup and vesicle formation, but complementary cell-type specific functions during vestibular and cochlear morphogenesis. The comparative analysis between mouse and chicken Gata2 and Gata3 expression revealed many conserved aspects, especially during later stages of inner ear development, while the expression was more divergent at early stages. Namely, expression of both Gata genes was initiated earlier in chicken than mouse otic epithelium relative to the morphogenetic stages. Likewise, important differences concerning Gata3 expression in the otic cup epithelium were detected between mouse and chicken, suggesting that distinct molecular mechanisms regulate otic vesicle closure in different vertebrate species. Temporally distinct Gata2 and Gata3 expression was also found during otic ganglion formation in mouse and chicken. Targeted inactivation of Gata3 in mouse embryos caused aberrant morphology of the otic vesicle that in severe cases was disrupted into two parts, a dorsal and a ventral vesicle. Detailed analyses of Gata3 mutant embryos unveiled a crucial role for GATA3 in the initial inner ear morphogenetic event, the invagination of the otic placode. A large-scale comparative expression analysis suggested that GATA3 could control cell adhesion and motility in otic epithelium, which could be important for early morphogenesis. GATA3 was also identified as the first factor to directly regulate Fgf10 expression in the otic epithelium and could thus influence the development of the semicircular ducts. Despite the serious problems in the early inner ear development, the otic sensory fate establishment and some vestibular hair cell differentiation was observable in pharmacologically rescued Gata3-/- embryos. Cochlear sensory differentiation was, however, completely blocked so that no auditory hair cells were detected. In contrast to the early morphogenetic phenotype in Gata3-/- mutants, conditional inactivation of Gata2 in mouse embryos resulted in a relatively late growth defect of the three semicircular ducts. GATA2 was required for the proliferation of the vestibular nonsensory epithelium to support growing of the three ducts. Concurrently, with the role in epithelial semicircular ducts, GATA2 was also required for the mesenchymal cell clearance from the vestibular perilymphatic region between the membranous labyrinth and bony capsule. The gamma-aminobutyric acid-secreting (GABAergic) neurons in the midbrain are clinically relevant since they contribute to fear, anxiety, and addiction regulation. The molecular mechanisms regulating the GABAergic neuronal development, however, are largely unknown. Using tissue-specific mutagenesis in mice, GATA2 was characterized as a critical determinant of the GABAergic neuronal fate in the midbrain. In Gata2-deficient mouse midbrain, GABAergic neurons were not produced, instead the Gata2-mutant cells acquired a glutamatergic neuronal phenotype. Gain-of-function experiments in chicken also revealed that GATA2 was sufficient to induce GABAergic differentiation in the midbrain.