bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue engineering of bone: the reconstructive surgeon's point of view
Authors: Kneser U. , Schaefer D. J. , Polykandriotis E. , Horch R. E.
Published: March 2007

Bone defects represent a medical and socioeconomic challenge. Different types of biomaterials are applied for reconstructive indications and receive rising interest. However, autologous bone grafts are still considered as the gold standard for reconstruction of extended bone defects. The generation of bioartificial bone tissues may help to overcome the problems related to donor site morbidity and size limitations. Tissue engineering is, according to its historic definition, an “interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function”. It is based on the understanding of tissue formation and regeneration and aims to rather grow new functional tissues than to build new spare parts. While reconstruction of small to moderate sized bone defects using engineered bone tissues is technically feasible, and some of the currently developed concepts may represent alternatives to autologous bone grafts for certain clinical conditions, the reconstruction of largevolume defects remains challenging. Therefore vascularization concepts gain on interest and the combination of tissue engineering approaches with flap prefabrication techniques may eventually allow application of bone‐tissue substitutes grown in vivo with the advantage of minimal donor site morbidity as compared to conventional vascularized bone grafts. The scope of this review is the introduction of basic principles and different components of engineered bioartificial bone tissues with a strong focus on clinical applications in reconstructive surgery. Concepts for the induction of axial vascularization in engineered bone tissues as well as potential clinical applications are discussed in detail.
Inwardly rectifying potassium channels (Kir) in central nervous system glia: a special role for Kir4.1 in glial functions
Authors: Butt Arthur M. , Kalsi Amanpreet
Published: March 2007

Glia in the central nervous system (CNS) express diverse inward rectifying potassium channels (Kir). The major function of Kir is in establishing the high potassium (K+) selectivity of the glial cell membrane and strongly negative resting membrane potential (RMP), which are characteristic physiological properties of glia. The classical property of Kir is that K+ flows inwards when the RMP is negative to the equilibrium potential for K+ (Ek), but at more positive potentials outward currents are inhibited. This provides the driving force for glial uptake of K+ released during neuronal activity, by the processes of “K+ spatial buffering” and “K+ siphoning”, considered a key function of astrocytes, the main glial cell type in the CNS. Glia express multiple Kir channel subtypes, which are likely to have distinct functional roles related to their differences in conductance, and sensitivity to intracellular and extracellular factors, including pH, ATP, G‐proteins, neurotransmitters and hormones. A feature of CNS glia is their specific expression of the Kir4.1 subtype, which is a major K+ conductance in glial cell membranes and has a key role in setting the glial RMP. It is proposed that Kir4.1 have a primary function in K+ regulation, both as homomeric channels and as heteromeric channels by co‐assembley with Kir5.1 and probably Kir2.0 subtypes. Significantly, Kir4.1 are also expressed by oligodendrocytes, the myelin‐forming cells of the CNS, and the genetic ablation of Kir4.1 are also expressed by Oligodendrocytes, the myelin‐forming cells of the CNS, and the genetic ablation of Kir4.1 results in severe hypomyelination. Hence, Kir, and in particular Kir4.1, are key regulators of glial functions, which in turn determine neuronal excitability and axonal conduction.
Arteriogenesis versus angiogenesis: similarities and differences
Authors: Heil M. , Eitenmüller Inka , Schmitz‐Rixen T. , Schaper W.
Published: March 2007

Cardiovascular diseases account for more than half of total mortality before the age of 75 in industrialized countries. To develop therapies promoting the compensatory growth of blood vessels could be superior to palliative surgical surgical interventions. Therefore, much effort has been put into investigating underlying mechanisms. Depending on the initial trigger, growth of blood vessels in adult organisms proceeds via two major processes, angiogenesis and arteriogenesis. While angiogenesis is induced by hypoxia and results in new capillaries, arteriogenesis is induced by physical forces, most importantly fluid shear stress. Consequently, chronically elevated fluid shear stress was found to be the strongest trigger under experimental conditions. Arteriogenesis describes the remodelling of pre‐existing arterio‐arteriolar anastomoses to completely developed and functional arteries. In both growth processes, enlargement of vascular wall structures was proposed to be covered by proliferation of existing wall cells. Recently, increasing evidence emerges, implicating a pivotal role for circulating cells, above all blood monocytes, in vascular growth processes. Since it has been shown that monocytes/macrophage release a cocktail of chemokines, growth factors and proteases involved in vascular growth, their contribution seems to be of a paracrine fashion. A similar role is currently discussed for various populations of bone‐marrow derived stem cells and endothelial progenitors. In contrast, the initial hypothesis that these cells ‐after undergoing a (trans‐)differentiation‐ contribute by a structural integration into the growing vessel wall, is increasingly challenged.
Morphological aspects of apoptosis in heart diseases
Authors: Takemura Genzou , Fujiwara Hisayoshi
Published: March 2007

It has been suggested that apoptosis may be responsible for a significant amount of cardiomyocyte death during acute myocardial infraction as well as for a progressive loss of surviving cells in failing hearts. Typical apoptosis can indeed be induced in cardiomyocytes at the experimental conditions. In actual heart diseases, in contrast, there is very little direct morphological evidence of apoptosis in cardiomyocytes occuring at any stage of myocardial infarction and heart failure, despite the availability of much indirect evidence that includes detection of DNA fragmentation and apoptosis‐related factors. For that reason, the potential efficacy of therapeutic intervention to prevent apoptosis remains controversial. This review will survey available data from both animals and humans to critically assess the role of cardiomyocyte apoptosis during myocardial infarction and its relevance to myocardial remodeling and during progression to heart failure. Also considered will be nonmyocyte interstitial cells, which have received less attention than myocytes despite definitive evidence of their apoptosis in the infarcted heart and recent studies suggesting that blockade of apoptosis among these cells mitigates postinfarction cardiac remodeling and heart failure. We conclude from our survey that there are many hurdles to surmount before regulation of apoptosis can be clinically applied in the treatment of myocardial infarction and heart failure.
Modern pathogenetic concepts of liver fibrosis suggest stellate cells and TGF‐β as major players and therapeutic targets
Authors: Gressner A. M. , Weiskirchen R.
Published: March 2007

Hepatic fibrosis is a scarring process that is associated with an increased and altered deposition of extracellular matrix in liver. At the cellular and molecular level, this progressive process is mainly characterized by cellular activation of hepatic stellate cells and aberrant activity of transforming growth factor‐β1 and its downstream cellular mediators. Although the cellular responses to this cytokine are complex, the signalling pathways of this pivotal cytokine during the fibrogenic response and its connection to other signal cascades are now understood in some detail. Based on the current advances in understanding the pleiotropic reactions during fibrogenesis, various inhibitors of transforming growth factor‐β were developed and are now being investigated as potential drug candidates in experimental models of hepatic injury. Although it is too early to favour one of these antagonists for the treatment of hepatic fibrogenesis in human, the experimental results obtained yet provide stimulatory impulses for the development of an effective treatment of choice in the not too distant future. The present review summarises the actual knowledge on the pathogenesis of hepatic fibrogenesis, the role of transforming growth factor‐β and its signalling pathways in promoting the fibrogenic response, and the therapeutic modalities that are presently in the spotlight of many investigations and are already on the way to take the plunge into clinical studies.
Epigenetics of prostate cancer: beyond DNA methylation
Authors: Schulz W. A. , Hatina J.
Published: March 2007

Epigenetic mechanisms permit the stable inheritance of cellular properties without changes in DNA sequence or amount. In prostate carcinoma, epigenetic mechanisms are essential for development and progression, complementing, amplifying and diversifying genetic alterations. DNA hypermethylation affects at least 30 individual genes, while repetitive sequences including retrotransposons and selected genes become hypomethylated. Hypermethylation of several genes occurs in a coordinate manner early in carcinogenesis and can be exploited for cancer detection, whereas hypomethylation and further hypermethylation events are associated with progression. DNA methylation alterations interact with changes in chromatin proteins. Prominent alterations at this level include altered patterns of histone modification, increased expression of the EZH2 polycomb histone methyltransferase, and changes in transcriptional corepressors and coactivators. These changes may make prostate carcinoma particularly susceptible to drugs targeting chromatin and DNA modifications. They relate to crucial alterations in a network of transcription factors comprising ETS family proteins, the androgen receptor, NKX3.1, KLF, and HOXB13 homeobox proteins. This network controls differentiation and proliferation of prostate epithelial cells integrating signals from hormones, growth factors and cell adhesion proteins that are likewise distorted in prostate cancer. As a consequence, prostate carcinoma cells appear to be locked into an aberrant state, characterized by continued proliferation of largely differentiated cells. Accordingly, stem cell characteristics of prostate cancer cells appear to be secondarily acquired. The aberrant differentiation state of prostate carcinoma cells also results in distorted mutual interactions between epithelial and stromal cells in the tumor that promote tumor growth, invasion, and metastasis.
Discovery of the ‘porosome’ the universal secretory machinery in cells
Authors: Anderson L. L.
Published: March 2007

The release of neurotransmitters at the nerve terminal for neurotransmission, release of insulin from β‐cells of the endocrine pancreas for regulating blood glucose levels, the release of growth hormone from GH cells of the pituitary gland to regulate body growth, or the expulsion of zymogen from exocrine pancreas to digest food, are only a few examples of key physiological processes made possible by cell secretion. It comes as no surprise that defects in cell secretion are the cause for numerous diseases, and have been under intense investigation for over half century. Only in the last decade, the molecular machinery and mechanism of cell secretion has become clear. Cell secretion involves the docking and transient fusion of membrane‐bound secretory vesicles at the base of plasma membrane structures called porosomes, and the regulated expulsion of intravesicular contents to the outside, by vesicle swelling. The discovery of the porosome in live cells, its morphology and dynamics at nanometer resolution and in real time, its isolation, its composition, and its structural and functional reconstitution in lipid membrane, are complete. The molecular mechanism of secretory vesicle fusion at the base of porosomes, and the regulated expulsion of intravesicular contents during cell secretion, are also resolved. In this minireview, the monumental discovery of the porosome, a new cellular structure at the cell plasma membrane, is briefly discussed.
N‐Acetyl‐L‐Cysteine abrogates fibrogenic properties of fibroblasts isolated from Dupuytren's disease by blunting TGF‐β signalling
Authors: Kopp Jürgen , Seyhan Harun , Müller Bastian , Lanczak Johanna , Pausch Elke , Gressner Axel M. , Dooley Steven , Horch Raymund E.
Published: March 2007

Dupuytren's disease, a benign fibroproliferative disorder of the palmar fascia, represents an ideal model to study tissue fibrosis. Transforming growth factor‐β1 (TGF‐β1) and its downstream Smad signalling system is well established as a key player during fibrogenesis. Thus, targeting this basic pathomechanism seems suitable to establish new treatment strategies. One such promising treatment involves the substance N‐acetyl‐L‐cysteine (NAC), shown to have antifibrotic properties in hepatic stellate cells and rat fibroblasts. In order to investigate antifibrotic effects of N‐acetyl‐L‐cysteine (NAC), fibroblasts were isolated from surgically resected fibrotic palmar tissues (Dupuytren fibroblasts, DF) and exposed to different concentrations of NAC and recombinant TGF‐β1. Fibroblasts isolated from tendon pulleys served as controls (control fibroblasts, CF). Smad signalling was investigated by a Smad binding element driven reporter gene analysis. Both cell types express TGF‐β1, indicating autocrine signalling in DF and CF. This was confirmed by comparing reporter gene activity from LacZ and Smad7 adenovirus infected cells. NAC treatment resulted in abrogation of Smad mediated signalling comparable to ectopically overexpressed Smad7, even when the cells were stimulated with recombinant TGF‐β1 or ectopically expressed a constitutively active TGF‐β receptor type I. Additionally, NAC dose‐dependently decreased expression of three major indicators of impaired fibrotic matrix turnover, namely alpha‐smooth muscle actin (α‐SMA), α 1 type I procollagen (CollA1), and plasminogen activator inhibitor‐type I (PAI‐1). Our results suggest that TGF‐β signalling and subsequent expression of fibrogenesis related proteins in Dupuytren's disease is abrogated by NAC thus providing a basis for a therapeutic strategy in Dupuytren's disease and other fibroproliferative disorders.
A new scoring system using multiple immunohistochemical markers for diagnosis of uterine smooth muscle tumors
Authors: Rath‐Wolfson Lea , Rosenblat Yevgenia , Halpern Marisa , Herbert M. , Hammel I. , Gal Rivka , Leabu M. , Koren Rumelia
Published: March 2007

The diagnosis of uterine smooth muscle neoplasms by light microscopy is difficult. Multiple classification schemes have been proposed based on mitotic rate, nuclear atypia, and the presence or absence of necrosis. None of these classification systems has been entirely successful. This study was undertaken to evaluate the use of selected immunohistochemical and histochemical markers in differentiating these tumors, in addition to accepted morphologic criteria. Ten cases of each of the following: leiomyosarcomas (LMS), atypical leiomyomas (AL), cellular leiomyomas (CL) and usual leiomyomas (UL), were classically evaluated for histological diagnosis and were stained for Ki‐67 (MIB‐1), bcl‐2 and p53 using monoclonal antibodies and the avidin‐biotin peroxidase method, and argyrophilic nucleolar organizer region (AgNORs). The number of stained cells was counted in the most positively stained region in a 4 mm2 square cover glass mounted on each slide. The mean value was calculated for each group of tumors. The data for Ki‐67 (MIB‐1), bcl‐2, p53 and AgNOR staining respectively, were significantly higher in LMS by comparison to UL, CL or AL. Because many singular cases had superimposed data being difficult to diagnose, a new scoring system for pathological evaluation was created. The results obtained by this scoring system suggest that immunohistochemical markers Ki‐67 (MIB‐1), bcl‐2, p53 together with the AgNOR staining could be useful, by the scoring system, as an adjunct to the current accepted morphologic criteria in differentiating smooth muscle tumors of the uterus.
Age‐associated changes in oxidative damage and the activity of antioxidant enzymes in rats with inherited overgeneration of free radicals
Authors: Sinitsyna Olga , Krysanova Zhanna , Ishchenko A. , Dikalova Anna E. , Stolyarov S. , Kolosova Nataliya , Vasunina Elena , Nevinsky G.
Published: March 2007

Reactive oxygen species have been hypothesized to play an important role in the process of aging. To investigate the correlation between oxidative stress and accumulation of protein and DNA damage, we have compared the age‐dependent levels of protein carbonyl groups and the activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase in cytosol and mitochondrial extracts from liver cells of Wistar and OXYS rats. The latter strain is characterized by increased sensitivity to free radicals. Faster age‐dependent increase in the level of protein carbonyl groups was found in OXYS as compared with Wistar rats. A complicated enzyme‐specific pattern of age‐dependent changes in the activities of antioxidant enzymes was observed. Long‐term uptake of dietary supplements Mirtilene forte (extract from the fruits of Vaccinium myrtillus L.) or Adrusen zinco (vitamin E complex with zinc, copper, selenium and ω‐3 polyunsaturated fatty acids) sharply decreased the level of protein oxidation in cytosol and mitochondrial extracts of hepatocytes of Wistar and of OXYS rats. Both dietary supplements increased the activity of catalase in the liver mitochondria of OXYS rats. Our results are in agreement with the shorter life‐span of OXYS and with the mitochondrial theory of aging, which postulates that accumulation of DNA and protein lesions leads to mitochondrial dysfunction and accelerates the process of aging.
Dobesilate diminishes activation of the mitogen ‐ activated protein kinase ERK1/2 in glioma cells
Authors: Cuevas P. , Diaz‐González Diana , Garcia‐Martin‐Córdova C. , Sánchez I. , Lozano Rosa Maria , Giménez‐Gallego G. , Dujovny M.
Published: March 2007

Fibroblast growth factors (FGFs) and their receptors, regularly expressed at high levels in gliomas, are further upregulated during the transition of the tumor from low‐ to high‐grade malignancy, and are essential for glioma progression. FGFs induce upregulation of the mitogen‐activated protein kinase (MAPK) signaling cascade in cultured glioma cells, which suggests that MAPK pathway participates in the FGF‐dependent glioma development. Recently, it has been shown that dobesilate, an inhibitor of FGF mitogenic activity, shows antiproliferative and proapoptotic activities in glioma cell cultures. Accordingly, it should be expected this new synthetic FGF inhibitor to affect the activation levels of MAPK. Here we report that immunocytochemical and Western blot data unequivocally show that treatment of cell cultures with dobesilate causes a significant decrease of the intracellular levels of ERK1/2 activation, one of the components of the MAPK signalling cascade. This finding supports an important role for dobesilate in glioma growth, suggesting that dobesilate should be a treatment to be born in mind for glioma management.
Differential upregulation of Nox homologues of NADPH oxidase by tumor necrosis factor‐α in human aortic smooth muscle and embryonic kidney cells
Authors: Moe K. T. , Aulia S. , Jiang F. , Chua Y. L. , Koh T. H. , Wong M. C. , Dusting G. J.
Published: March 2007

NADPH oxidases are important sources of vascular superoxide, which has been linked to the pathogenesis of atherosclerosis. Previously we demonstrated that the Nox4 subunit of NADPH oxidase is a critical catalytic component for superoxide production in quiescent vascular smooth muscle cells. In this study we sought to determine the role of Nox4 in superoxide production in human aortic smooth muscle cells (AoSMC) and embryonic kidney (HEK293) cells under proinflammatory conditions. Incubation with tumor necrosis factor‐α (TNF‐α, 10 ng/ml) for 12h increased superoxide production in both cell types, whereas angiotensin II, platelet‐derived growth factor or interleukin‐1β had little effects. Superoxide production was completely abolished by the NADPH oxidase inhibitors diphenyline iodonium and apocynin, but not by inhibitors of xanthine oxidase, nitric oxide synthase or mitochondrial electron transport. TNF‐α upregulated the expression of Nox4 in AoSMC at both message and protein levels, while Nox1 and Nox2 were unchanged. In contrast, upregulation of Nox2 appeared to mediate the enhanced superoxide production by TNF‐α in HEK293 cells. We suggest that Nox4 may be involved in increased superoxide generation in vascular smooth muscle cells under proinflammatory conditions.
Human mesenchymal stem cells in contact with their environment: surface characteristics and the integrin system
Authors: Docheva Denitsa , Popov Cvetan , Mutschler Wolf , Schieker Matthias
Published: March 2007

Mesenchymal stem cells and their clinical relevance

Integrins and their importance

Cell surface molecules on MSCs

Integrin system of MSCs

Engagement of integrins in MSC differentiation, attachment to coating materials, survival on scaffolds and neoplastic transformation

Conclusions

The identification of mesenchymal stem cells (MSCs) in adult human tissues and the disclosure of their self‐renew‐al and multi‐lineage differentiation capabilities have provided exciting prospects for cell‐based regeneration and tis‐sue engineering. Although a considerable amount of data is available describing MSCs, there is still lack of information regarding the molecular mechanisms that govern their adhesion and migration. In this work, we will review the current state of knowledge on integrins and other adhesion molecules found to be expressed on MSCs. The dis‐cussed topics include the characteristics of MSCs and their clinical applications, integrins and their central role in cell‐matrix attachment and migration, and comments on mobilization, differentiation and contribution to tumour development. Finally, by understanding the complex and fundamental pathways by which MSCs attach and migrate, it might be possible to fine‐tune the strategies for effective and safe use of MSCs in regenerative therapies.
PPARγ activation by thiazolidinediones (TZDs) may modulate breast carcinoma outcome: the importance of interplay with TGFβ signalling
Authors: Jarrar Mohammed H. , Baranova Ancha
Published: March 2007

Introduction

PPARγ‐dependent and ‐independent action of TZDs

Effects of TZDs in the breast epithelium

Crosstalks of the PPARγ signalling with OR, STAT5B and NF‐κB pathways

PPARγ activation may interfere with TGFβ signalling

Effects of TZDs in rodent models

Current and future prospects in the studies of the anticancerous effects of TZDs in human beings

The thiazolidinediones (TZDs) are a class of synthetic antidiabetic drugs exerting its action primarily upon acti‐vation of the peroxisome proliferator‐activated receptor‐γ (PPARγ). Given the widespread incidence of diabetes type II and lifelong exposure of these patients to TZDs, there is a possibility that chronic treatment with TZD modifies clinical phenotypes of other common human diseases, for example breast carcinoma. There is evidence that TZDs act as breast carcinoma suppression agents, at least in the in vitro and animal models. Stimulation of the PPARγ by TZDs interferes with oestrogen receptor signalling, STAT5B and NF‐κB signalling cascades. On the other hand, TZDs repress TGFβ signalling, a well‐known suppressor of the initial stages of breast carcinoma development. Another layer of complexity arises at the later stages of tumour development, when TGFβ acts as a tumour promoter: its overexpression is associated with poor prognosis, higher degree of tumour vascularization and metastasis. Longitudinal studies of breast carcinoma development in chronic TZD users are needed. In this review, we dissect possible interplays between chronic exposure of breast tis‐sue to TZDs and TGFβ signalling and predict influence of TZD exposure on cancer‐related clinical outcome.
Expression of RhoA by inflammatory macrophages and T cells in rat experimental autoimmune neuritis
Authors: Zhang Zhiren , Fauser Uwe , Schluesener Hermann J.
Published: March 2007

RhoA is one of the best‐studied members of Rho GTPases. Experimental autoimmune neuritis (EAN), which is characterized by infiltration of T cells and macrophages into the peripheral nervous system, is an autoantigen‐specific T‐cell‐mediated animal model of human Guillain‐BarrŽ Syndrome. In this study, RhoA expression has been investigated in the dorsal/ventral roots of EAN rats by immunohistochemistry. A significant accumulation of RhoA+ cells was observed on Day 12, with a maximum around Day 15, correlating to the clinical severity of EAN. In dorsal/ventral roots of EAN, RhoA+ cells were seen in perivascular areas but also in the parenchyma. Furthermore, double‐labelling experiments showed that the major cellular sources of RhoA were reactive macrophages and T cells. In conclusion, this is the first demonstration of the presence of RhoA in the dorsal/ventral roots of EAN. The time courses and cellular sources of RhoA together with the functions of RhoA indicate that RhoA may function to facilitate macrophage and T‐cell infiltration in EAN and therefore could be a potential therapeutic target.
Inhibition of adhesion molecule expression on human venous endothelial cells by non‐viral siRNA transfection
Authors: Walker Tobias , Wendel Hans P. , Tetzloff Liane , Raabe Claudia , Heidenreich Olaf , Simon Perikles , Scheule Albertus M. , Ziemer Gerhard
Published: March 2007

Objective: Expression of adhesion molecule receptors on venous endothelial cells crucially influences the fate of venous grafts by mediating leukocyte‐endothelium interactions. These interactions include adhesion of leuko‐cytes to the endothelium, followed by transendothelial migration, leading to neointimal hyperplasia (NIH) and finally graft occlusion. Therefore, inhibition of adhesion molecule expression may be a promising strategy to improve the quality of venous grafts.We tested the efficiency of non‐viral transfection of human venous endothe‐lial cells (HVEC) with short interfering RNA (siRNA) to specifically down‐regulate adhesion molecule expression.

Methods: Primary cultures of HVEC were examined for expression of the adhesion molecules ICAM1, VCAM1 and E‐selectin (SELE) after non viral siRNA transfection. Adhesion molecule expression was measured by flow cytom‐etry, real‐time polymerase chain reaction and immunoblotting after stimulation with TNF‐α, an inflammatory cytokine.

Results: Non‐transfected cells showed a strong increase of adhesion molecule expression following cytokine stimulation (P < 0.01). Upon transfection with specific siRNAs a sixfold decrease in ICAM1 (P < 0.001) and SELE expression and cell positivity (P < 0.05) and a twofold decrease in VCAM1 expression and cell positiv‐ity (P < 0.01) Pcould be observed. SiRNA‐mediated gene suppression of adhesion molecules was also reflected by corresponding decreases in adhesion protein and transcript levels.

Conclusions: The expression of adhesion molecules on HVECs can be effectively inhibited by specific siRNAs using a safe, non‐viral transfection approach. This is a promising tool to pre‐condition venous bypass grafts in order to interfere with endothelium‐leukocyte interactions and to prohibit neointima thickening or ath‐erosclerosis, which are regarded to be the most important causes of venous graft failure.
Ca2+‐pumps and Na+–Ca2+‐exchangers in coronary artery endothelium versus smooth muscle
Authors: Szewczyk Magdalena M. , Davis Kim A. , Samson Sue E. , Simpson Fiona , Rangachari Patangi K. , Grover Ashok K.
Published: March 2007

Vascular endothelial cells (EC) and smooth muscle cells (SMC) require a decrease in cytoplasmic Ca2+ concentration after activation. This can be achieved by Ca2+ sequestration by the sarco‐/endoplasmic reticulum Ca2+ pumps (SERCA) and Ca2+ extrusion by plasma membrane Ca2+ pumps (PMCA) and Na+–Ca2+‐exchangers (NCX). Since the two cell types differ in their structure and function, we compared the activities of PMCA, NCX and SERCA in pig coronary artery EC and SMC, the types of isoforms expressed using RT‐PCR, and their protein abundance using Western blots. The activity of NCX is higher in EC than in SMC but those of PMCA and SERCA is lower. Consistently, the protein abundance for NCX protein is higher in EC than in SMC and those of PMCA and SERCA is lower. Based on RT‐PCR experiments, the types of RNA present are as follows: EC for PMCA1 while SMC for PMCA4 and PMCA1; EC for SERCA2 and SERCA3 and SMC for SERCA2. Both EC and SMC express NCX1 (mainly NCX1.3). PMCA, SERCA and NCX differ in their affinities for Ca2+ and regulation. Based on these observations and the literature, we conclude that the tightly regulated Ca2+ removal systems in SMC are consistent with the cyclical control of contractility of the filaments and those in EC are consistent with Ca2+ regulation of the endothelial nitric oxide synthase near the cell surface. The differences between EC and SMC should be considered in therapeutic interventions of cardiovascular diseases.
Toll‐like receptor 4 in atherosclerosis
Authors: Li Hongli , Sun Baogui
Published: March 2007

Introduction

Toll‐like receptor 4 structure and its functions

TLR4 expression in atherosclerotic lesions

Endothelial cells

Vascular smooth muscle cells (VSMCs)

Adventitial fibroblasts

Dendritic cells (DCs)

Macrophages

Role of TLR4 in atherosclerosis

TLR4 in early atherosclerotic lesion

TLR4 in advanced atherosclerotic lesion

TLR4 in plaque rupture

TLR4 in arterial remodelling

TLR4 polymorphisms in atherosclerosis

Conclusion

Toll‐like receptor 4 (TLR4) is key regulators of both innate and adaptive immune responses. TLR4 recognizes pathogen‐associated molecular patterns (PAMPs) and activates the inflammatory cells. The function of TLR4 in atherosclerosis has been investigated in mouse knockout studies and epidemiological studies of human TLR4 polymorphisms. These studies have shown that TLR4 function affects the initiation and progression of atherosclerosis. This article reviews the biological functions and clinical implications of TLR4 in atherosclerosis.
Constitutive and ligand‐induced nuclear localization of oxytocin receptor
Authors: Kinsey Conan G. , Bussolati Gianni , Bosco Martino , Kimura Tadashi , Pizzorno Marie C. , Chernin Mitchell I. , Cassoni Paola , Novak Josef F.
Published: March 2007

Oxytocin receptor (OTR) is a membrane protein known to mediate oxytocin (OT) effects, in both normal and neoplastic cells. We report here that human osteosarcoma (U2OS, MG63, OS15 and SaOS2), breast cancer (MCF7), and primary human fibroblastic cells (HFF) all exhibit OTR not only on the cell membrane, but also in the various nuclear compartments including the nucleolus. Both an OTR‐GFP fusion protein and the native OTR appear to be localized to the nucleus as detected by transfection and/or confocal immunofluorescence, respectively. Treatment with oxytocin causes internalization of OTR and the resulting vesicles accumulate in the vicinity of the nucleus and some of the perinuclear OTR enters the nucleus. Western blots indicate that OTR in the nucleus and on the plasma membrane are likely to be the same biochemical and immunological entities. It appears that OTR is first visible in the nucleoli and subsequently disperses within the nucleus into 4–20 spots while some of the OTR diffuses throughout the nucleoplasm.The behaviour and kinetics of OTR‐GFP and OTR are different, indicating interference by GFP in both OTR entrance into the nucleus and subsequent relocalization of OTR within the nucleus. There are important differences among the tested cells, such as the requirement of a ligand for transfer of OTR in nuclei. A constitutive internalization of OTR was found only in osteosarcoma cells, while the nuclear localization in all other tested cells was dependent on ligand binding. The amount of OTR‐positive material within and in the vicinity of the nucleus increased following a treatment with oxytocin in both constitutive and ligand‐dependent type of cells. The evidence of OTR compartmentalization at the cell nucleus (either ligand‐dependent or constitutive) in different cell types suggests still unknown biological functions of this protein or its ligand and adds this G‐protein‐coupled receptor to other heptahelical receptors displaying this atypical and unexpected nuclear localization.
Transient ventricular fibrillation and myosin heavy chain isoform profile
Authors: Manoach M. , Tribulova N. , Vogelezang D. , Thomas S. , Podzuweit T.
Published: March 2007

The present paper deals with spontaneous ventricular defibrillation in mammals and the possibility to facilitate its occurrence. Clinical and experimental evidence suggest that in the majority of cases, ventricular fibrillation (VF) is permanent, requiring defibrillation by electric shock. However, a growing number of reports show that VF can terminate spontaneously in various mammals, including human beings.The mechanisms involved in spontaneous ventricular defibrillation are controversial. Available reports imply that intracellular Ca2+ overload is the key event triggering VF and preventing its reversal. Since the sarcoplasmatic reticulum is the main intracellular Ca2+ regulating organelle and the activity of the cardiac SR Ca2+ ATPase (SERCA 2a) is its prime element of Ca2+ sequestration, spontaneous ventricular defibrillation likely requires high level of SERCA 2a activity. We suggest that mammalian hearts with high SERCA 2a activity defibrillate spontaneously and those with low activity only after its enhancement. Since high SERCA 2a activity is co‐expressed with the myosin heavy chain (MHC) isoform V1, we assumed that those hearts preferentially expressing V1 MHC are able to defibrillate spontaneously. Hearts with small amounts of V1 MHC and correspondingly lower level of SERCA 2a activity can only defibrillate following administration of compounds that augment SERCA 2a activity and prevent intracellular Ca2+ overload.
Simultaneous bilateral external dacryocystorhinostomy
Authors: Yazici Bulent , Akova Berna
Published: March 2007

Purpose:  To assess the outcome and complications of simultaneous bilateral external dacryocystorhinostomy (DCR) surgery.

Methods:  The records of all patients who underwent bilateral external DCR in a single session between November 1999 and October 2005 were reviewed.

Results:  The study cohort comprised 59 patients (50 females, nine males; age range: 6–72 years; mean age: 49 years). Nasolacrimal duct obstruction was acquired primarily in 54 patients, congenitally in three and secondary to sinonasal surgery in two. Thirteen eyes of eight patients had a history of unsuccessful lacrimal surgery. The operation was performed under local anaesthesia plus sedation in 54 patients (92%). Total intraoperative haemorrhage varied from 3 mL to 200 mL (median: 17 mL; mean: 37 mL). Excessive intraoperative haemorrhage (= 100 mL) occurred in five patients (9%). Total duration of surgery varied between 70 and 140 min, with an average of 89 min. Postoperatively, early bleeding requiring intranasal tamponade developed in one patient (2%) and bilateral wound infection in one patient (2%). Surgical success rate was 95%. Mean follow‐up time was 8.8 months (range: 3–38 months).

Conclusion:  This study supports that the simultaneous bilateral external DCR surgery may not adversely affect surgical success and complication rates.
Carboxyfullerenes localize within mitochondria and prevent the UVB‐induced intrinsic apoptotic pathway
Authors: Chirico Filomena , Fumelli Cristiana , Marconi Alessandra , Tinari Antonella , Straface Elisabetta , Malorni Walter , Pellicciari Roberto , Pincelli Carlo
Published: March 2007

Abstract:  Carboxyfullerenes (CF) act as free radical scavengers in many cell settings and prevent apoptosis in vitro and in vivo. CF protect normal human keratinocytes from UVB‐induced apoptosis, although the mechanisms underlying this effect remain to be clarified. Double‐staining confocal laser microscopy revealed that CF penetrate the cell and colocalize with cytokeratin‐18 within cytoplasm. This localization was confirmed by transmission electron microscopy that showed CF intermingled with keratin filaments. Moreover, double‐staining with the mitochondrial marker anti‐F1‐ATPase antibody demonstrated that CF are expressed in mitochondria. Transmission electron microscopy confirmed that CF actually localize within mitochondria. Then, normal human keratinocytes were UVB‐irradiated in the presence or absence of CF at different doses. CF protected keratinocytes from apoptosis induced by reactive oxygen species. CF scavenging effect is associated with a partial blockade of the UVB‐induced intrinsic apoptotic pathway by down‐modulating caspase‐9 activation and cytochrome c release, and by inhibiting the down‐regulation of the inhibitor of apoptosis proteins (IAP) survivin, livin, IAP‐1 and IAP‐2. Finally, CF prevented the cleavage of Bid, up‐regulation of Bad and down‐regulation of Mcl‐1 induced by UVB. Taken together, these results indicate that CF penetrate human keratinocytes, localize within mitochondria where they act both by scavenging free radicals and by protecting cells from apoptosis.
mTOR as a potential therapeutic target for treatment of keloids and excessive scars
Authors: Ong C. T. , Khoo Y. T. , Mukhopadhyay A. , Do D. V. , Lim I. J. , Aalami O. , Phan T. T.
Published: March 2007

Abstract:  Keloid is a dermal fibroproliferative disorder characterized by excessive deposition of extracellular matrix (ECM) components such as collagen, glycoproteins and fibronectin. The mammalian target of rapamycin (mTOR) is a serine/theronine kinase which plays an important role in the regulation of metabolic processes and translation rates. Published reports have shown mTOR as regulator of collagen expression and its inhibition induces a decrease in ECM deposition. Our aim was to investigate the role of mTOR in keloid pathogenesis and investigate the effect of rapamycin on proliferating cell nuclear antigen (PCNA), cyclin D1, collagen, fibronectin and alpha‐smooth muscle actin (α‐SMA) expression in normal fibroblasts (NF) and keloid fibroblasts (KF). Tissue extracts obtained from keloid scar demonstrated elevated expression of mTOR, p70KDa S6 kinase (p70S6K) and their activated forms, suggesting an activated state in keloid scars. Serum stimulation highlighted the heightened responsiveness of KF to mitogens and the importance of mTOR and p70S6K during early phase of wound healing. Application of rapamycin to monoculture NF and KF, dose‐ and time‐dependently downregulates the expression of cytoplasmic PCNA, cyclin D1, fibronectin, collagen and α‐SMA, demonstrating the anti‐proliferative effect and therapeutic potential of rapamycin in the treatment of keloid scars. The inhibitory effect of rapamycin was found to be reversible following recovery in the expression of proteins following the removal of rapamycin from the culture media. These results demonstrate the important role of mTOR in the regulation of cell cycle and the expression of ECM proteins: fibronectin, collagen and α‐SMA.
Spontaneous neoplasia in the baboon (Papio spp.)
Authors: Cianciolo Rachel E. , Butler Stephanie D. , Eggers Jeffery S. , Dick Edward J. , Leland M. Michelle , De La Garza Melissa , Brasky Kathleen M. , Cummins Larry B. , Hubbard Gene B.
Published: March 2007

Background  There are several comprehensive reviews of spontaneous neoplasia in non‐human primates that compile individual cases or small numbers of cases, but do not provide statistical analysis of tumor incidence, demographics, or epidemiology.

Methods  This paper reports all spontaneous neoplasms (n = 363) diagnosed over a 15‐year period in a baboon colony with an average annual colony population of 4000.

Results  A total of 363 spontaneous neoplasms were diagnosed in 313 baboons: 77 cases were males (25%) and 236 were females (75%); ages ranged from 1 month to 33 years (mean 16.5, median 17).

Conclusions  The organ systems affected in descending order of number of neoplasms were hematopoietic organs (n = 101, 28%), urogenital tract (n = 78, 21%), integument (n = 43, 12%), alimentary tract (n = 43, 12%), endocrine organs (n = 40, 11%), nervous system (n = 33, 9%), musculoskeletal system (n = 5, 1%), and respiratory system (n = 4, 1%). Malignant cases numbered 171 (47%); 192 (53%) cases were benign.
Ultrasound‐guided follicular aspiration in squirrel monkeys
Authors: Schuler A.M. , Westberry J.M. , Parks V.L. , Kuehl T.J. , Abee C.R.
Published: March 2007

The objective of this study was to test whether ultrasound‐guided oocyte retrieval is an effective mechanism for collecting oocytes in squirrel monkeys. Although ultrasound‐guided follicular aspiration has been described in Old World primates, oocyte retrieval in New World primates is typically performed via laparoscopy or laparotomy. However, these procedures, especially the first, can be invasive. Ultrasound has been used for pregnancy monitoring in multiple species of primates including Saimiri spp. Transabdominal ultrasound as a diagnostic tool is non‐invasive. Transabdominal ultrasound was utilized to visualize ovarian follicles during aspiration under light anesthesia. This procedure resulted in collection of a total of 29 oocytes from six animals with minimal post‐procedural pain. Manipulated animals were returned to the social group the same day.
Developmental disturbance of maxillary lateral incisor after trauma
Authors: Tozoglu Sinan , Yolcu Umit , Tozoglu Ummuhan
Published: March 2007

Abstract –  Traumatic injury to a primary tooth has a potential to damage the underlying permanent tooth germ. It may lead to developmental disturbance of permanent dentition. The impaction of the permanent maxillary central incisor because of the root dilaceration in children is rare. The purpose of this paper is to report a developmental disturbance of a permanent right maxillary lateral incisor in a 12‐year‐old girl with a history of trauma at an early age.
Influence of Different Atropine Therapy Strategies on Fenthion‐Induced Organ Dysfunction in Rats
Authors: Fidan Huseyin , Sahin Onder , Ela Yuksel , Kilbas Aynur , Bas Orhan , Yavuz Yucel , Sahin Dursun Ali , Altuntas Irfan
Published: March 2007

Abstract:  We studied the influence of dose and timing of atropine therapy on fenthion‐induced organ dysfunction. Thirty‐six rats were randomized into six groups. All rats in the five groups except the control group were intoxicated with fenthion. The high‐dose atropine group received 2 mg/kg of atropine, whereas the low‐dose group received 100 µg/kg of atropine every hour for 24 hr. One group received 2 mg/kg of atropine in the first 4 hr of intoxication while the other group received 2 mg/kg of atropine in the last 4 hr before killed, which for all rats was 24 hr after intoxication. Pseudocholinesterase and aspartate aminotransferase and alanine aminotransferase levels and histopathological markers of lung, brain and liver were studied. None of our atropine therapy strategies in this study totally prevented harm on the three organs. Although the high dose of atropine administered for 24 hr had the least harmful markers for lung, it also had the most harmful markers for brain and liver. We did not succeed in finding a unique therapy strategy in our models beneficial for all studied organs in fenthion intoxication in rats. Atropine administration strategy should be oriented for the most affected organ pathology in fenthion intoxication.
Protective Effects of Caffeic Acid Phenethyl Ester, Vitamin C, Vitamin E and N‐Acetylcysteine on Vancomycin‐Induced Nephrotoxicity in Rats
Authors: Ocak Sabahattin , Gorur Sadik , Hakverdi Sibel , Celik Sefa , Erdogan Suat
Published: March 2007

Abstract:   The objective of this study was to compare the beneficial effects of caffeic acid phenethyl ester (CAPE), vitamin C, vitamin E and N‐acetylcysteine on vancomycin‐induced nephrotoxicity. Thirty rats were randomly devided into six groups: (i) control; (ii) vancomycin, 200 mg/kg administrated via intraperitoneal route; (iii) vancomycin plus CAPE – vancomycin with 10 µmol/kg CAPE; (iv) vancomycin plus vitamin C – vancomycin (intraperitoneally) with 200 mg/dl vitamin C in drinking water; (v) vancomycin plus vitamin E – vancomycin with 1000 mg/kg body weight vitamin E (intramuscularly); and (vi) vancomycin plus N‐acetylcysteine – vancomycin with 10 mg/kg body weight (intraperitoneally) of N‐acetylcysteine. Vancomycin treatments were started 1 day after the first administrations of these agents and continued for 7 days. At the end of the experiments, catalase activity was significantly decreased by vancomycin in kidney homogenates (P < 0.05). Vitamin E, vitamin C, N‐acetylcysteine and CAPE administrations decreased the blood urea nitrogen levels increased by vancomycin, although significant differences were detected only in the vitamins E and C groups (P < 0.05). Increased renal malondialdehyde and nitric oxide levels by vancomycin were significantly suppressed by agents used in the study (P < 0.05). Histopathological examination demonstrated prominent damages in the vancomycin‐treated group. Vitamin E was the most beneficial agent on vancomycin‐induced tubular damage, followed by vitamin C, N‐acetylcysteine and CAPE treatments, respectively. The data suggest that vitamin E, as well as vitamin C, N‐acetylcysteine and CAPE, could be useful for reducing the detrimental effects on vancomycin‐induced toxicity in kidneys.
Estimating Hydraulic Properties of Volcanic Aquifers Using Constant‐Rate and Variable‐Rate Aquifer Tests1
Authors: Rotzoll Kolja , El‐Kadi Aly I. , Gingerich Stephen B.
Published: March 2007

Abstract:  In recent years the ground‐water demand of the population of the island of Maui, Hawaii, has significantly increased. To ensure prudent management of the ground‐water resources, an improved understanding of ground‐water flow systems is needed. At present, large‐scale estimations of aquifer properties are lacking for Maui. Seven analytical methods using constant‐rate and variable‐rate withdrawals for single wells provide an estimate of hydraulic conductivity and transmissivity for 103 wells in central Maui. Methods based on constant‐rate tests, although not widely used on Maui, offer reasonable estimates. Step‐drawdown tests, which are more abundantly used than other tests, provide similar estimates as constant‐rate tests. A numerical model validates the suitability of analytical solutions for step‐drawdown tests and additionally provides an estimate of storage parameters. The results show that hydraulic conductivity is log‐normally distributed and that for dike‐free volcanic rocks it ranges over several orders of magnitude from 1 to 2,500 m/d. The arithmetic mean, geometric mean, and median values of hydraulic conductivity are respectively 520, 280, and 370 m/d for basalt and 80, 50, and 30 m/d for sediment. A geostatistical approach using ordinary kriging yields a prediction of hydraulic conductivity on a larger scale. Overall, the results are in agreement with values published for other Hawaiian islands.