Concise review: Humanized models of tumor immunology in the 21st century: Convergence of cancer research and tissue engineering

Despite positive testing in animal studies, more than 80% of novel drug candidates fail to proof their efficacy when tested in humans. This is primarily due to the use of preclinical models that are not able to recapitulate the physiological or pathological processes in humans. Hence, one of the key challenges in the field of translational medicine is to “make the model organism mouse more human.” To get answers to questions that would be prognostic of outcomes in human medicine, the mouse's genome can be altered in order to create a more permissive host that allows the engraftment of human cell systems. It has been shown in the past that these strategies can improve our understanding of tumor immunology. However, the translational benefits of these platforms have still to be proven. In the 21st century, several research groups and consortia around the world take up the challenge to improve our understanding of how to humanize the animal's genetic code, its cells and, based on tissue engineering principles, its extracellular microenvironment, its tissues, or entire organs with the ultimate goal to foster the translation of new therapeutic strategies from bench to bedside. This article provides an overview of the state of the art of humanized models of tumor immunology and highlights future developments in the field such as the application of tissue engineering and regenerative medicine strategies to further enhance humanized murine model systems.

Electrocardiographic repolarization variables in detecting myocardial infarction and ischemic injury : From body surface potential mapping to a single lead

The aim of the studies was to improve the diagnostic capability of electrocardiography (ECG) in detecting myocardial ischemic injury with a future goal of an automatic screening and monitoring method for ischemic heart disease. The method of choice was body surface potential mapping (BSPM), containing numerous leads, with intention to find the optimal recording sites and optimal ECG variables for ischemia and myocardial infarction (MI) diagnostics. The studies included 144 patients with prior MI, 79 patients with evolving ischemia, 42 patients with left ventricular hypertrophy (LVH), and 84 healthy controls. Study I examined the depolarization wave in prior MI with respect to MI location. Studies II-V examined the depolarization and repolarization waves in prior MI detection with respect to the Minnesota code, Q-wave status, and study V also with respect to MI location. In study VI the depolarization and repolarization variables were examined in 79 patients in the face of evolving myocardial ischemia and ischemic injury. When analyzed from a single lead at any recording site the results revealed superiority of the repolarization variables over the depolarization variables and over the conventional 12-lead ECG methods, both in the detection of prior MI and evolving ischemic injury. The QT integral, covering both depolarization and repolarization, appeared indifferent to the Q-wave status, the time elapsed from MI, or the MI or ischemia location. In the face of evolving ischemic injury the performance of the QT integral was not hampered even by underlying LVH. The examined depolarization and repolarization variables were effective when recorded in a single site, in contrast to the conventional 12-lead ECG criteria. The inverse spatial correlation of the depolarization and depolarization waves in myocardial ischemia and injury could be reduced into the QT integral variable recorded in a single site on the left flank. In conclusion, the QT integral variable, detectable in a single lead, with optimal recording site on the left flank, was able to detect prior MI and evolving ischemic injury more effectively than the conventional ECG markers. The QT integral, in a single-lead or a small number of leads, offers potential for automated screening of ischemic heart disease, acute ischemia monitoring and therapeutic decision-guiding as well as risk stratification.

Growth factor induction in intervertebral disc tissue: Observations in basic mechanisms of disc degeneration and rearrangement

The intervertebral disc is composed of concentrically arranged components: annulus fibrosus, the transition zone, and central nucleus pulposus. The major disc cell type differs in various parts of the intervertebral disc. In annulus fibrosus a spindle shaped fibroblast-like cell mainly dominates, whereas in central nucleus pulposus the more rounded chondrocyte-like disc cell is the major cell type. At birth the intervertebral disc is well vascularized, but during childhood and adolescence blood vessels become smaller and less numerous. The adult intervertebral disc is avascular and is nourished via the cartilage endplates. On the other hand, degenerated and prolapsed intervertebral discs are again vascularized, and show many changes compared to normal discs, including: nerve ingrowth, change in collagen turnover, and change in water content. Furthermore, the prolapsed intervertebral disc tissue has a tendency to decrease in size over time. Growth factors are polypeptides which regulate cell growth, extracellular matrix protease activity, and vascularization. Oncoproteins c-Fos and c-Jun heterodimerize, forming the AP-1 transcription factor which is expressed in activated cells. In this thesis the differences of growth factor expression in normal intervertebral disc, the degenerated intervertebral disc and herniated intervertebral disc were analyzed. Growth factors of particular interest were basic fibroblast growth factor (bFGF or FGF-2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and transforming growth factor beta (TGFβ). Cell activation was visualized by the expression of the AP-1 transcription promoters c-Fos and c-Jun. The expression was shown with either mono- or polyclonal antibodies by indirect avidin-biotin-peroxidase immunohistochemical staining method. The normal control material was collected from a tissue bank of five organ donors. The degenerated disc material was from twelve patients operated on for painful degenerative disc disease, and herniated disc tissue material was obtained from 115 patients operated on for sciatica. Normal control discs showed only TGFβ immunopositivity. All other factors studied were immunonegative in the control material. Prolapsed disc material was immunopositive for all factors studied, and this positivity was located either in the disc cells or in blood vessels. Furthermore, neovascularization was noted. Disc cell immunoreaction was shown in chondrocyte-like disc cells or in fibroblast-like disc cells, the former being expressed especially in conglomerates (clusters of disc cells). TGFβ receptor induction was prominent in prolapsed intervertebral disc tissue. In degenerated disc material, the expression of growth factors was analyzed in greater detail in various parts of the disc: nucleus pulposus, anterior annulus fibrosus and posterior annulus fibrosus. PDGF did not show any immunoreactivity, whereas all other studied growth factors were localized either in chondrocyte-like disc cells, often forming clusters, in fibroblast-like disc cells, or in small capillaries. Many of the studied degenerated discs showed tears in the posterior region of annulus fibrosus, but expression of immunopositive growth factors was detected throughout the entire disc. Furthermore, there was a difference in immunopositive cell types for different growth factors. The main conclusion of the thesis, supported by all substudies, is the occurrence of growth factors in disc cells. They may be actively participating in a network regulating disc cell growth, proliferation, extracellular matrix turnover, and neovascularization. Chondrocyte-like disc cells, in particular, expressed growth factors and oncoproteins, highlighting the importance of this cell type in the basic pathophysiologic events involved in disc degeneration and disc rearrangement. The thesis proposes a hypothesis for cellular remodelling in intervertebral disc tissue. In summary, the model presents an activation pattern of different growth factors at different intervertebral disc stages, mechanisms leading to neovascularization of the intervertebral disc in pathological conditions, and alteration of disc cell shape, especially in annulus fibrosus. Chondrocyte-like disc cells become more numerous, and these cells are capable of forming clusters, which appear to be regionally active within the disc. The alteration of the phenotype of disc cells expressing growth factors from fibroblast-like disc cells to chondrocyte-like cells in annulus fibrosus, and the numerous expression of growth factor expressing disc cells in nucleus pulposus, may be a key element both during pathological degeneration of the intervertebral disc, and during the healing process after trauma.

Pathophysiology of Congenital Nephrotic Syndrome of the Finnish type

Congenital nephrotic syndrome of the Finnish type (NPHS1) is an autosomal recessive disease which is highly enriched in the Finnish population. It is caused by mutations in the NPHS1 gene encoding for nephrin, which is a major component of the glomerular filtration barrier in the kidney. Patients with NPHS1 have heavy proteinuria and nephrotic syndrome (NS) from birth and develop renal fibrosis in early childhood. Renal transplantation (TX) is the only curative treatment for NPHS1. These patients form the largest group of pediatric kidney transplant children in our country. The NPHS1 kidneys are removed in infancy and they serve as an excellent human material for studies of the pathophysiology of proteinuric kidney diseases. Sustained proteinuria is a major factor leading to end-stage renal failure and understanding this process is crucial for nephrology. In this study we investigated the glomerular and tubulointerstitial changes that occur in the NPHS1 kidneys during infancy as well as the expression of nephrin in non-renal tissues. We also studied the pathology and management of recurrent proteinuria in kidney grafts transplanted to NPHS1 children. Severe renal lesions evolved in patients with NPHS1 during the first months of life. Glomerular sclerosis developed through progressive mesangial sclerosis, and capillary obliteration was an early consequence of this process. Shrinkage of the glomerular tuft was common, whereas occlusion of tubular opening or protrusion of the glomerular tuft into subepithelial space or through the Bowman's capsule were not detected. Few inflammatory cells were detected in the mesangial area. The glomerular epithelial cells (podocytes) showed severe ultrastructural changes and hypertrophy. Podocyte proliferation and apoptosis were rare, but moderate amounts of podocytes were detached and ended up in the urine. The results showed that endocapillary lesions not extracapillary lesions, as generally believed were important for the sclerotic process in the NPHS1 glomeruli. In the tubulointerstitium, severe lesions developed in NPHS1 kidneys during infancy. Despite heavy proteinuria, tubular epithelial cells (TECs) did not show transition into myofibroblasts. The most abundant chemokines in NPHS1 tissue were neutrophil activating protein-2 (NAP-2), macrophage inhibiting factor (MIF), and monocyte chemoattractant protein-1 (MCP-1). Interstitial inflammation and fibrosis were first detected in the paraglomerular areas and the most abundant inflammatory cells were monocytes/macrophages. Arteries and arterioles showed intimal hypertrophy, but the pericapillary microvasculature remained quite normal. However, excessive oxidative stress was evident in NPHS1 kidneys. The results indicated that TECs were relatively resistant to the heavy tubular protein load. Nephrin was at first thought to be podocyte specific, but some studies especially in experimental animals have suggested that nephrin might also be expressed in non-renal tissues such as pancreas and central nervous system. The knowledge of nephrin biology is important for the evaluation of nephrin related diseases. In our study, no significant amounts of nephrin protein or mRNA were detected in non-renal tissues of man and pig as studied by immunohistochemistry and in situ hybridization. The phenotype analysis of NPHS1 children, who totally lack nephrin, revealed no marked impairment in the neurological, testicular, or pancreatic function speaking against the idea that nephrin would play an important functional role outside the kidney. The NPHS1 kidneys do not express nephrin and antibodies against this major glomerular filter protein have been observed in NPHS1 children after renal TX most likely as an immune reaction against a novel antigen. These antibodies have been associated with the development of recurrent NS in the kidney graft of NPHS1 patients. In our study, a third of the NPHS1 patients homozygous for Fin-Major mutation developed recurrent NS in the transplanted graft. Re-transplantations were performed to patients who lost their graft due to recurrent NS and heavy proteinuria immediately developed in all cases. While 73% of the patients had detectable serum anti-nephrin antibodies, the kidney biopsy findings were minimal. Introduction of plasma exchange (PE) to the treatment of recurrent nephroses increased the remission rate from 54% to 89%. If remission was achieved, recurrent NS did not significantly deteriorate the long term graft function. In conclusion, the results show that the lack of nephrin in podocyte slit diaphragm in NPHS1 kidneys induces progressive mesangial expansion and glomerular capillary obliteration and inflicts interstitial fibrosis, inflammation, and oxidative stress with surprisingly little involvement of the TECs in this process. Nephrin appears to have no clinical significance outside the kidney. Development of antibodies against nephrin seems to be a major cause of recurrent NS in kidney grafts of NPHS1 patients and combined use of PE and cyclophosphamide markedly improved remission rates.

X-ray scattering and diffraction enhanced imaging studies of in vitro breast tissues

This thesis is a study of the x-ray scattering properties of tissues and tumours of the breast. Clinical radiography is based on the absorption of the x-rays when passing right through the human body and gives information about the densities of the tissues. Besides being absorbed, x-rays may change their direction within the tissues due to elastic scattering or even to refraction. The phenomenon of scattering is a nuisance to radiography in general, and to mammography in particular, because it reduces the quality of the images. However, scattered x-rays bear very useful information about the structure of the tissues at the supra-molecular level. Some pathologies, like breast cancer, produce alterations to the structures of the tissues, being especially evident in collagen-rich tissues. On the other hand, the change of direction due to refraction of the x-rays on the tissue boundaries can be mapped. The diffraction enhanced imaging (DEI) technique uses a perfect crystal to convert the angular deviations of the x-rays into intensity variations, which can be recorded as images. This technique is of especial interest in the cases were the densities of the tissues are very similar (like in mammography) and the absorption images do not offer enough contrast. This thesis explores the structural differences existing in healthy and pathological collagen in breast tissue samples by the small-angle x-ray scattering (SAXS) technique and compares these differences with the morphological information found in the DEI images and the histo-pathology of the same samples. Several breast tissue samples were studied by SAXS technique in the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Scattering patterns of the different tissues of the breast were acquired and compared with the histology of the samples. The scattering signals from adipose tissue (fat), connective tissue (collagen) and necrotic tissue were identified. Moreover, a clear distinction could be done between the scattering signals from healthy collagen and from collagen from an invasive tumour. Scattering from collagen is very characteristic. It includes several scattering peaks and scattering features that carry information about the size and the spacing of the collagen fibrils in the tissues. It was found that the collagen fibrils in invaded tumours were thinner and had a d-spacing length 0,7% longer that fibrils from healthy tumours. The scattering signals from the breast tissues were compared with the histology by building colour-coded maps across the samples. They were also imaged with the DEI technique. There was a total agreement between the scattering maps, the morphological features seen in the images and the information of the histo- pathological examination. The thesis demonstrates that the x-ray scattering signal can be used to characterize tissues and that it carries important information about the pathological state of the breast tissues, thus showing the potential of the SAXS technique as a possible diagnostic tool for breast cancer.

Investigation of the interaction between non-small cell lung cancer cells and immortalised normal bronchial epithelial cells

Non-small cell lung cancer consists of a diverse range of molecular and pathological features. This may be due in part to the critical interaction between normal and lung cancer cells. Consequently resulting in ‘normal’ cells acting in a malignant fashion. This project aims to identify pathways responsible for this altered ‘normal’ behaviour.

Heme oxygenase-1 in cardiovascular diseases

Myocardial infarction (MI) and heart failure are major causes of morbidity and mortality worldwide. Treatment of MI involves early restoration of blood flow to limit infarct size and preserve cardiac function. MI leads to left ventricular remodeling, which may eventually progress to heart failure, despite the established pharmacological treatment of the disease. To improve outcome of MI, new strategies for protecting the myocardium against ischemic injury and enhancing the recovery and repair of the infarcted heart are needed. Heme oxygenase-1 (HO-1) is a stress-responsive and cytoprotective enzyme catalyzing the degradation of heme into the biologically active reaction products biliverdin/bilirubin, carbon monoxide (CO) and free iron. HO-1 plays a key role in maintaining cellular homeostasis by its antiapoptotic, anti-inflammatory, antioxidative and proangiogenic properties. The present study aimed, first, at evaluating the role of HO-1 as a cardioprotective and prohealing enzyme in experimental rat models and at investigating the potential mechanisms mediating the beneficial effects of HO-1 in the heart. The second aim was to evaluate the role of HO-1 in 231 critically ill intensive care unit (ICU) patients by investigating the association of HO-1 polymorphisms and HO-1 plasma concentrations with illness severity, organ dysfunction and mortality throughout the study population and in the subgroup of cardiac patients. We observed in an experimental rat MI model, that HO-1 expression was induced in the infarcted rat hearts, especially in the infarct and infarct border areas. In addition, pre-emptive HO-1 induction and CO donor pretreatment promoted recovery and repair of the infarcted hearts by differential mechanisms. CO promoted vasculogenesis and formation of new cardiomyocytes by activating c-kit+ stem/progenitor cells via hypoxia-inducible factor 1 alpha, stromal cell-derived factor 1 alpha (SDF-1a) and vascular endothelial growth factor B, whereas HO-1 promoted angiogenesis possibly via SDF-1a. Furthermore, HO-1 protected the heart in the early phase of infarct healing by increasing survival and proliferation of cardiomyocytes. The antiapoptotic effect of HO-1 persisted in the late phases of infarct healing. HO-1 also modulated the production of extracellular matrix components and reduced perivascular fibrosis. Some of these beneficial effects of HO-1 were mediated by CO, e.g. the antiapoptotic effect. However, CO may also have adverse effects on the heart, since it increased the expression of extracellular matrix components. In isolated perfused rat hearts, HO-1 induction improved the recovery of postischemic cardiac function and abrogated reperfusion-induced ventricular fibrillation, possibly in part via connexin 43. We found that HO-1 plasma levels were increased in all critically ill patients, including cardiac patients, and were associated with the degree of organ dysfunction and disease severity. HO-1 plasma concentrations were also higher in ICU and hospital nonsurvivors than in survivors, and the maximum HO-1 concentration was an independent predictor of hospital mortality. Patients with the HO-1 -413T/GT(L)/+99C haplotype had lower HO-1 plasma concentrations and lower incidence of multiple organ dysfunction. However, HO-1 polymorphisms were not associated with ICU or hospital mortality. The present study shows that HO-1 is induced in response to stress in both experimental animal models and severely ill patients. HO-1 played an important role in the recovery and repair of infarcted rat hearts. HO-1 induction and CO donor pretreatment enhanced cardiac regeneration after MI, and HO-1 may protect against pathological left ventricular remodeling. Furthermore, HO-1 induction potentially may protect against I/R injury and cardiac dysfunction in isolated rat hearts. In critically ill ICU patients, HO-1 plasma levels correlate with the degree of organ dysfunction, disease severity, and mortality, suggesting that HO-1 may be useful as a marker of disease severity and in the assessment of outcome of critically ill patients.

POP-inhibiittorin KYP-2047 vaikutukset angiogeneesiin in vitro

Angiogeneesi on tärkeä ilmiö elimistön fysiologiassa, mutta myös lukuisissa patologisissa tiloissa. Angiogeneesi on monivaiheinen prosessi, joka sisältää angiogeneesiä indusoivia ja sitä inhiboivia tekijöitä tasapainossa keskenään. Useat tutkimukset puoltavat sitä, että tymosiini ȕ4 (Tȕ4) ja tetrapeptidi Ac-SDKP (N-asetyyliseryyli- aspartyyli-lysyyli-proliini) indusoivat angiogeneesiä in vitro ja in vivo. Tutkimukset viittaavat myös siihen, että prolyylioligopeptidaasi (POP) hydrolysoi peptidifragmentin Ac- SDKP Tȕ4:n (43 ah) proliinin jälkeen. POP on laajalti esiintyvä seriiniproteaasi, joka pystyy pilkkomaan vain alle 30 aminohapon oligopeptidejä. Tȕ4:n tulee siksi pilkkoutua ensin jonkin, vielä tuntemattoman peptidaasin johdosta. POP:ia on löydetty eniten aivoista, minkä vuoksi sitä on tutkittu varsinkin muistin ja oppimisen häiriötiloissa sekä neurodegeneratiivisten sairausten yhteydessä. POP:in todellinen fysiologinen merkitys on kuitenkin vielä selvittämättä. Tämän pro gradun kirjallisuusosiossa selvitetään angiogeneesiin liittyvien tekijöiden yhteyksiä sekä kuvataan angiogeenisten Tȕ4:n, Ac-SDKP:n ja POP:in ominaisuuksia, esiintymistä ja toimintaa. Kokeellisen osion tarkoituksena oli osoittaa, osallistuvatko POP ja Tȕ4 tetrapeptidin Ac-SDKP muodostumiseen ja kapillaarimuodostumiseen ja edelleen, voidaanko POPaktiivisuutta, tetrapeptidi- ja kapillaarimuodostumista estää spesifisellä POP-inhibiittorilla, KYP-2047:llä. Kokeellinen osa oli kaksiosainen. Ensimmäisessä osassa tutkittiin POPaktiivisuutta ja suoritettiin Ac-SDKP –pitoisuusmittauksia ajanjaksolla 0-180 min Wistarkannan rotista tehdyillä homogenaateilla. Tutkimusryhminä olivat 0,1 ja 0,5 μM KYP-2047 (+2 μM Tȕ4), 1:20 (0,625 μM) humaaniperäinen rekombinantti-POP (+ 2 μM Tȕ4), 2 μM Tȕ4 (pos. kontrolli) ja raakahomogenaatti (neg. kontrolli). Toisessa osassa tutkittiin kapillaarimuodostumista ajanjaksolla 0-180 min humaaniperäisillä napanuoralaskimon primaariendoteelisoluilla MatrigelTM Matrix -päällystetyllä 48- kuoppalevyllä, jolle oli siirrostettu 50 000 solua/kuoppa. Naudan seerumilla ja antibiooteilla käsitellyt tutkimusryhmät olivat 5 ja 10 μM KYP-2047 (+4 μM Tȕ4), 1:20 (0,625 μM) humaaniperäinen rekombinantti-POP (+4 μM Tȕ4), 4 μM Tȕ4 (pos. kontrolli) ja DMEM (neg. kontrolli). Kuoppia inkuboitiin ja kapillaarimuodostuminen kuvattiin valomikroskoopilla digitaalikameralla. Kutakin tutkimusryhmää pipetoitiin kolmeen rinnakkaiseen kuoppaan ja kokeet toistettiin neljästi. Sulkeutuneiden kapillaarien lukumäärä laskettiin manuaalisesti ja tuloksista tehtiin tilastollinen analyysi. 7ȕ4:n ja POP:in havaittiin molempien osallistuvan tetrapeptidin AC-SDKP muodostumiseen munuaishomogenaateissa. Primaariendoteelisolut muodostivat selkeitä kapillaareja Matrigelilla, erityisesti POP- ja Tȕ4–ryhmissä. KYP-2047 inhiboi tehokkaasti POP:ia kaikissa kokeissa osoittautuen hyväksi antiangiogeeniseksi yhdisteeksi. Angiogeneesin mekanismien ja POP:in, Tȕ4:n ja Ac-SDKP:n yhteyksien selvittäminen vaatii luonnollisesti vielä lisätutkimuksia.

Plexin B2 in mouse and zebrafish development

Plexins (plxn) are receptors of semaphorins (sema), which were originally characterized as axon guidance cues. Semaphorin-plexin signalling has now been implicated in many other developmental and pathological processes. In this thesis, my first aim was to study the expression of plexins during mouse development. My second aim was to study the function of Plexin B2 in the development of the kidney. Thirdly, my objective was to elucidate the evolutionary conservation of Plexin B2 by investigating its sequence, expression and function in developing zebrafish. I show by in situ hybridisation that plexins are widely expressed also in the non-neuronal tissues during mouse development. Plxnb1 and Plxnb2, for example, are expressed also in the ureteric epithelium, developing glomeruli and undifferentiated metanephric mesenchyme of the developing kidney. Plexin B2-deficient (Plxnb2-/-) mice die before birth and have severe defects in the nervous system. I demonstrate that they develop morphologically normal but hypoplastic kidneys. The ureteric epithelium of Plxnb2-/- kidneys has fewer branches and a lower rate of proliferating cells. 10% of the embryos show unilateral double ureters and kidneys. The defect in the branching is intrinsic to the epithelium as the isolated ureteric epithelium grown in vitro fails to respond to Glial-cell-line-derived neurotrophic factor (Gdnf). We prove by co-immunoprecipitation that Plexin B2 interacts with the Gdnf-receptor Ret. Sema4C, the Plexin B2 ligand, increases branching of the ureteric epithelium in controls but not in Plxnb2-/- kidney explants. These results suggest that Sema4C-Plexin B2 signalling modulates ureteric branching in a positive manner, possibly through directly regulating the activation of Ret. I cloned the zebrafish orthologs of Plexin B2, Plexin B2a and B2b. The corresponding proteins contain the conserved domains the B-subfamily plexins. Especially the expression pattern of plxnb2b recapitulates many aspects of the expression pattern of Plxnb2 in mouse. Plxnb2a and plxnb2b are expressed, for example, in the pectoral fins and at the midbrain-hindbrain region during zebrafish development. The nearly complete knockdown of Plexin B2a alone or together with the 45% knockdown of Plexin B2b did not interfere with the normal development of the zebrafish. In conclusion, my thesis reveals that plexins are broadly expressed during mouse embryogenesis. It also shows that Sema4C-Plexin B2 signalling modulates the branching of the ureteric epithelium during kidney development, perhaps through a direct interaction with Ret. Finally, I show that the sequence and expression of Plexin B2a and B2b are conserved in zebrafish. Their knockdown does not, however, result in the exencephaly phenotype of Plxnb2-/- mice.

A Recursive Perspective on Discursive Legitimation and Organizational Action in Mergers and Acquisitions

This paper challenges the predominant view that legitimation is merely a specific phase in merger or acquisition processes. We argue that a better understanding of postmerger organizational dynamics calls for conceptualization of discursive legitimation as an inherent part of unfolding merger processes. In particular, we focus on the recursive relationship between legitimation and organizational action. We have two objectives: to outline a theoretical model that helps one to understand the dynamics of discursive legitimation and organizational action in postmerger organizations, and to examine a revealing case to distinguish the inherent risks and problems in discursive legitimation. Our case analysis focuses on the merger between the French pharmaceutical companies BioMérieux and Pierre Fabre. We adopt a critical multimethod approach and distinguish specific discursive dynamics and pathological tendencies in this case. The analysis highlights the unintended consequences of discursive legitimation, the central role of sensegiving and sensehiding in discursive legitimation, the inherently political nature of legitimation and the risks associated with politicization, the special problems associated with fashionable discourses and the role of the media, the use of specific discursive strategies for legitimation and delegitimation, and the crucial role of actual integration results. This analysis adds to the existing research on mergers and acquisitions by treating discursive legitimation as part of the merger dynamics. In particular, our case analysis provides a new explanation for merger failure. We also believe that the recursive model connecting discursive legitimation and delegitimation strategies to concrete organizational action makes a more general contribution to our understanding of organizational legitimation.

A recursive perspective on discursive legitimation and organizational action in mergers and acquisitions

This paper challenges the predominant view that legitimation is merely a specific phase in merger or acquisition processes. We argue that a better understanding of postmerger organizational dynamics calls for conceptualization of discursive legitimation as an inherent part of unfolding merger processes. In particular, we focus on the recursive relationship between legitimation and organizational action. We have two objectives: to outline a theoretical model that helps one to understand the dynamics of discursive legitimation and organizational action in postmerger organizations, and to examine a revealing case to distinguish the inherent risks and problems in discursive legitimation. Our case analysis focuses on the merger between the French pharmaceutical companies BioMérieux and Pierre Fabre. We adopt a critical multimethod approach and distinguish specific discursive dynamics and pathological tendencies in this case. The analysis highlights the unintended consequences of discursive legitimation, the central role of sensegiving and sensehiding in discursive legitimation, the inherently political nature of legitimation and the risks associated with politicization, the special problems associated with fashionable discourses and the role of the media, the use of specific discursive strategies for legitimation and delegitimation, and the crucial role of actual integration results. This analysis adds to the existing research on mergers and acquisitions by treating discursive legitimation as part of the merger dynamics. In particular, our case analysis provides a new explanation for merger failure. We also believe that the recursive model connecting discursive legitimation and delegitimation strategies to concrete organizational action makes a more general contribution to our understanding of organizational legitimation.

ErbB-2 expression and its association with other biological parameters of breast cancer among Indian women

Overexpression of the epidermal growth factor receptor family genes, which include ErbB-1, 2, 3 and 4, has been implicated in a number of cancers. We have studied the extent of ErbB-2 overexpression among Indian women with sporadic breast cancer. Methods: Immmunohistochemistry and genomic polymerase chain reaction (PCR) were used to study the ErbB2 overexpression. ErbB2 status was correlated with other clinico-pathological parameters, including patient survival. Results: ErbB-2 overexpression was detected in 43.2% (159/368) of the cases by immunohistochemistry. For a sub-set of patients (n = 55) for whom total DNA was available, ErbB-2 gene amplification was detected in 25.5% (14/55) of the cases by genomic PCR. While the ErbB2 overexpression was significantly higher in patients with lymphnode (χ2 = 12.06, P≤ 0.001), larger tumor size (χ2 = 8.22, P = 0.042) and ductal carcinoma (χ2 = 15.42, P ≤ 0.001), it was lower in patients with disease-free survival (χ2 = 22.13, P ≤ 0.001). Survival analysis on a sub-set of patients for whom survival data were available (n = 179) revealed that ErbB-2 status (χ2 =25.94, P ≤ 0.001), lymphnode status (χ2 = 12.68, P ≤ 0.001), distant metastasis (χ2 = 19.49, P ≤ 0.001) and stage of the disease (χ2 = 28.04, P ≤0.001) were markers of poor prognosis. Conclusions: ErbB-2 overexpression was significantly greater compared with the Western literature, but comparable to other Indian studies. Significant correlation was found between ErbB-2 status and lymphnode status, tumor size and ductal carcinoma. ErbB-2 status, lymph node status, distant metastasis and stage of the disease were found to be prognostic indicators.

Effective treatment of infectious diseases: A nonlinear adaptive control theoretic approach

A nonlinear adaptive system theoretic approach is presented in this paper for effective treatment of infectious diseases that affect various organs of the human body. The generic model used does not represent any specific disease. However, it mimics the generic immunological dynamics of the human body under pathological attack, including the response to external drugs. From a system theoretic point of view, drugs can be interpreted as control inputs. Assuming a set of nominal parameters in the mathematical model, first a nonlinear controller is designed based on the principle of dynamic inversion. This treatment strategy was found to be effective in completely curing "nominal patients". However, in some cases it is ineffective in curing "realistic patients". This leads to serious (sometimes fatal) damage to the affected organ. To make the drug dosage design more effective, a model-following neuro-adaptive control design is carried out using neural networks, which are trained (adapted) online. From simulation studies, this adaptive controller is found to be effective in killing the invading microbes and healing the damaged organ even in the presence of parameter uncertainties and continuing pathogen attack.

Extending lagrange interpolation to develop a 4-node quadrilateral element

Today finite element method is a well established tool in engineering analysis and design. Though there axe many two and three dimensional finite elements available, it is rare that a single element performs satisfactorily in majority of practical problems. The present work deals with the development of 4-node quadrilateral element using extended Lagrange interpolation functions. The classical univariate Lagrange interpolation is well developed for 1-D and is used for obtaining shape functions. We propose a new approach to extend the Lagrange interpolation to several variables. When variables axe more than one the method also gives the set of feasible bubble functions. We use the two to generate shape function for the 4-node arbitrary quadrilateral. It will require the incorporation of the condition of rigid body motion, constant strain and Navier equation by imposing necessary constraints. The procedure obviates the need for isoparametric transformation since interpolation functions are generated for arbitrary quadrilateral shapes. While generating the element stiffness matrix, integration can be carried out to the accuracy desired by dividing the quadrilateral into triangles. To validate the performance of the element which we call EXLQUAD4, we conduct several pathological tests available in the literature. EXLQUAD4 predicts both stresses and displacements accurately at every point in the element in all the constant stress fields. In tests involving higher order stress fields the element is assured to converge in the limit of discretisation. A method thus becomes available to generate shape functions directly for arbitrary quadrilateral. The method is applicable also for hexahedra. The approach should find use for development of finite elements for use with other field equations also.