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1.
Foods ; 12(18)2023 Sep 08.
Article in English | MEDLINE | ID: mdl-37761083

ABSTRACT

In recent years, people have become increasingly interested in adopting a healthy diet, which also extends to healthy snacks, such as chips. Understanding the interplay of factors that influence the preference decisions concerning food products is very helpful in market segmentation for identifying specific groups of consumers with similar needs. This study aims to obtain a better understanding of Romanian consumers' preference for organic vegetable chips vs. classic potato chips. The research involved a transversal, cross-sectional, descriptive, exploratory, and correlational design. Data were collected based on a questionnaire (1060 participants) and processed with the SPSS 22 program, using the Pearson chi-square test and binary logistic regression as statistical procedures. Significant differences were found regarding the distribution of the respondents who prefer organic vegetable chips vs. classic potato chips based on socio-demographic characteristics. The results of the binary logistic regression analysis (χ2 = 102,906, df = 22, N = 909, p < 0.001) indicate that education level and frequency of consumption have a statistically significant impact on the preference for organic vegetable chips. The obtained results can contribute to a better understanding of Romanian consumers' preferences, acting as a knowledge stage in the adoption of a healthy eating style.

2.
Article in English | MEDLINE | ID: mdl-36554445

ABSTRACT

In the last few decades, humans have consumed more resources than in all of previous history. Hence, we are living in times in which the topic of environmental protection is a global concern. The paper aims to conduct a systematic literature review on consumer behavior, as well as identifying the main factors that interfere with consumer behavior toward green products. A total of 37 studies were found and systematized using inclusion and exclusion criteria. The papers were selected only if they featured research on consumer perceptions of green products. Using this search strategy, a literature analysis was performed based on papers extracted from Web of Science, Emerald Insights, Springer Link, and Science Direct. As a result, various factors that influence consumer behavior toward green products were identified, such as social norms, natural environmental orientation, the company's perceived green image, green product characteristics, perceived risks and inconvenience of buying green products, perceived benefits of buying green products, institutional trust, sociodemographic characteristics, and consumer confidence. Even though completing a systematic literature review is not something new in academic research, the novelty of this paper is found in its theme: consumer behavior toward green products. Although the analyzed articles highlight quite varied reasons, the articles emphasize that the green products should take into account the needs, expectations, and perceptions of customers.


Subject(s)
Conservation of Natural Resources , Consumer Behavior , Humans , Trust , Mental Processes
3.
Int J Mol Sci ; 23(16)2022 Aug 14.
Article in English | MEDLINE | ID: mdl-36012381

ABSTRACT

The following review is focused on carrageenan, a heteroglycan-based substance that is a very significant wound healing biomaterial. Every biomaterial has advantages and weaknesses of its own, but these drawbacks are typically outweighed by combining the material in various ways with other substances. Carrageenans' key benefits include their water solubility, which enables them to keep the wound and periwound damp and absorb the wound exudate. They have low cytotoxicity, antimicrobial and antioxidant qualities, do not stick to the wound bed, and hence do not cause pain when removed from the wounded region. When combined with other materials, they can aid in hemostasis. This review emphasizes the advantages of using carrageenan for wound healing, including the use of several mixes that improve its properties.


Subject(s)
Anti-Infective Agents , Wound Healing , Anti-Infective Agents/pharmacology , Anti-Infective Agents/therapeutic use , Antioxidants/pharmacology , Antioxidants/therapeutic use , Biocompatible Materials/pharmacology , Biocompatible Materials/therapeutic use , Carrageenan
4.
Article in English | MEDLINE | ID: mdl-35329099

ABSTRACT

The COVID-19 pandemic has created important changes in all areas, highlighting many vulnerabilities, but also opportunities based on the use of technology. This paper aims to provide an overview of the online educational process from two perspectives-that of students and that of professors from Romanian universities. Data were collected from 844 students from Romanian universities disregarding the area of study. To achieve the main goal of this paper, both qualitative (in-depth interviews) and quantitative methods (surveys) were used, the data being processed using the SPSS Statistical software. The results of this paper highlight the discrepancy between the perspectives of the two parties directly involved in the university educational process. The study shows that the pandemic forced both stakeholders to work harder than before, which negatively affected the way the educational process unfolded, the pleasure of the teaching/learning process, the level of enthusiasm, and sometimes even the academic results. The final conclusions of this paper also highlight the need to make financial investments for the acquisition of licenses to create virtual animations or simulations, as well as for training teachers in their use. Research also indicates that to maintain students' attention in class, especially online, teachers should use new teaching strategies, such as the use of debates and brainstorming sessions.


Subject(s)
COVID-19 , COVID-19/epidemiology , Humans , Pandemics , Romania/epidemiology , Students , Universities
5.
J Pers Med ; 11(9)2021 Sep 07.
Article in English | MEDLINE | ID: mdl-34575668

ABSTRACT

Chronic wounds represent a major public health issue, with an extremely high cost worldwide. In healthy individuals, the wound healing process takes place in different stages: inflammation, cell proliferation (fibroblasts and keratinocytes of the dermis), and finally remodeling of the extracellular matrix (equilibrium between metalloproteinases and their inhibitors). In chronic wounds, the chronic inflammation favors exudate persistence and bacterial film has a special importance in the dynamics of chronic inflammation in wounds that do not heal. Recent advances in biopolymer-based materials for wound healing highlight the performance of specific alginate forms. An ideal wound dressing should be adherent to the wound surface and not to the wound bed, it should also be non-antigenic, biocompatible, semi-permeable, biodegradable, elastic but resistant, and cost-effective. It has to give protection against bacterial, infectious, mechanical, and thermal agents, to modulate the level of wound moisture, and to entrap and deliver drugs or other molecules This paper explores the roles of alginates in advanced wound-dressing forms with a particular emphasis on hydrogels, nanofibers networks, 3D-scaffolds or sponges entrapping fibroblasts, keratinocytes, or drugs to be released on the wound-bed. The latest research reports are presented and supported with in vitro and in vivo studies from the current literature.

6.
Article in English | MEDLINE | ID: mdl-34360472

ABSTRACT

The COVID-19 pandemic has created the conditions for the expansion of teleworking (TW) in numerous sectors and organizations, and higher education institutions (HEIs) have had to adapt to this context. This paper aims to identify and analyze five factors (technology, individual involvement and skills, physical inactivity, psychological well-being, and household activities) that influence the effort and results in TW and education (E) in HEIs from the perspective of their key internal stakeholders. The data were gathered by a mix of qualitative and quantitative research methods, such as interviews and surveys. They were analyzed and interpreted through factorial analysis that uses the presentation of the main components as an extraction method, with the Varimax rotation method adopting Kaiser normalization, and processed with SPSS statistical software. This study shows that the effort and results of the key internal stakeholders of HEIs are influenced by the five factors. In this respect, students' results are negatively influenced by technology and physical inactivity factors. Moreover, the efforts of auxiliary and non-teaching staff are highly positively influenced by the psychological well-being factor and their results are positively influenced by the individual involvement and skills factor and negatively influenced by the household activities factor.


Subject(s)
COVID-19 , Pandemics , Humans , Romania , SARS-CoV-2 , Teleworking
7.
Transplantation ; 103(8): 1630-1638, 2019 08.
Article in English | MEDLINE | ID: mdl-30896677

ABSTRACT

BACKGROUND: Hepatocyte transplantation (Hctx) is a potentially attractive method for the treatment of acute liver failure and liver-based metabolic disorders. Unfortunately, the procedure is hampered by the instant blood-mediated inflammatory reaction (IBMIR), a thromboinflammatory response elicited by the vascular innate immune system, causing activation of the coagulation and complement systems and clearance of transplanted cells. Observations have also revealed platelets adhered to the surface of the hepatocytes (Hc). To establish Hctx as a clinical treatment, all factors that trigger IBMIR need to be identified and controlled. This work explores the expression of von Willebrand factor (VWF) on isolated Hc resulting in tethering of platelets. METHODS: VWF on Hc was studied by flow cytometry, confocal microscopy, immunoblot, and real-time polymerase chain reaction. Interaction between Hc and platelets was studied in a Chandler loop model. Adhesion of platelets to the hepatocyte surface was demonstrated by flow cytometry and confocal microscopy. RESULTS: Isolated Hc constitutively express VWF on their cell surface and mRNA for VWF was found in the cells. Hc and platelets, independently of coagulation formed complexes, were shown by antibody blocking studies to be dependent on hepatocyte-associated VWF and platelet-bound glycoprotein Ibα. CONCLUSIONS: VWF on isolated Hc causes, in contact with blood, adhesion of platelets, which thereby forms an ideal surface for coagulation. This phenomenon needs to be considered in hepatocyte-based reconstitution therapy and possibly even in other settings of cell transplantation.


Subject(s)
Blood Platelets/metabolism , Gene Expression Regulation , Hepatocytes/metabolism , Liver Transplantation , Platelet Adhesiveness/physiology , RNA/genetics , von Willebrand Factor/genetics , Blotting, Western , Cryopreservation , Female , Flow Cytometry , Hepatocytes/pathology , Hepatocytes/transplantation , Humans , Male , Microscopy, Confocal , Protein Binding , von Willebrand Factor/biosynthesis
8.
Ups J Med Sci ; 121(2): 81-95, 2016 May.
Article in English | MEDLINE | ID: mdl-27124642

ABSTRACT

Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting ß-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future.


Subject(s)
Blood Flow Velocity , Islets of Langerhans/blood supply , Animals , Blood Glucose/metabolism , Blood Pressure , Capillaries/metabolism , Hemodynamics , Hormones/metabolism , Humans , Insulin/metabolism , Insulin-Secreting Cells/metabolism , Microspheres , Neurotransmitter Agents/metabolism , Pancreas/metabolism , Perfusion , Regional Blood Flow , Veins/metabolism
9.
Acta Biomater ; 35: 194-205, 2016 Apr 15.
Article in English | MEDLINE | ID: mdl-26876877

ABSTRACT

Infusion of therapeutic cells into humans is associated with immune responses, including thromboinflammation, which result in a large loss of transplanted cells. To address these problems, heparinization of the cell surfaces was achieved by a cell-surface modification technique using polyethylene glycol-conjugated phospholipid (PEG-lipid) derivatives. A short heparin-binding peptide was conjugated to the PEG-lipid for immobilization of heparin conjugates on the surface of human mesenchymal stem cells (hMSCs) and human hepatocytes. Here three kinds of heparin-binding peptides were used for immobilizing heparin conjugates and examined for the antithrombogenic effects on the cell surface. The heparinized cells were incubated in human whole blood to evaluate their hemocompatibility by measuring blood parameters such as platelet count, coagulation markers, complement markers, and Factor Xa activity. We found that one of the heparin-binding peptides did not show cytotoxicity after the immobilization with heparin conjugates. The degree of binding of the heparin conjugates on the cell surface (analyzed by flow cytometer) depended on the ratio of the active peptide to control peptide. For both human MSCs and hepatocytes in whole-blood experiments, no platelet aggregation was seen in the heparin conjugate-immobilized cell group vs. the controls (non-coated cells or control peptide). Also, the levels of thrombin-antithrombin complex (TAT), C3a, and sC5b-9 were significantly lower than those of the controls, indicating a lower activation of coagulation and complement. Factor Xa analysis indicated that the heparin conjugate was still active on the cell surface at 24h post-coating. It is possible to immobilize heparin conjugates onto hMSC and human hepatocyte surfaces and thereby protect the cell surfaces from damaging thromboinflammation. STATEMENT OF SIGNIGFICANCE: We present a promising approach to enhance the biocompatibility of therapeutic cells. Here we used short peptide-conjugated PEG-lipid for cell surface modification and heparin conjugates for the coating of human hepatocytes and MSCs. We screened the short peptides to find higher affinity for heparinization of cell surface and performed hemocompatibility assay of heparinized human hepatocytes and human MSCs in human whole blood. Using heparin-binding peptide with higher affinity, not only coagulation activation but also complement activation was significantly suppressed. Thus, it was possible to protect human hepatocytes and human MSCs from the attack of thromboinflammatory activation, which can contribute to the improvement graft survival.


Subject(s)
Cell Membrane/metabolism , Heparin/therapeutic use , Hepatocytes/transplantation , Inflammation/drug therapy , Lipids/chemistry , Mesenchymal Stem Cell Transplantation , Peptides/therapeutic use , Polyethylene Glycols/chemistry , Thrombosis/drug therapy , Amino Acid Sequence , Antithrombins/metabolism , Cell Membrane/drug effects , Cell Survival/drug effects , Female , Heparin/pharmacology , Hepatocytes/cytology , Hepatocytes/drug effects , Humans , Inflammation/pathology , Male , Materials Testing , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/drug effects , Peptides/chemistry , Peptides/pharmacology , Thrombosis/complications
10.
Pancreas ; 45(4): 533-40, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26495792

ABSTRACT

OBJECTIVES: Progranulin (PGRN) promotes cell growth and cell cycle progression in several cell types and contributes to tumorigenesis in diverse cancers. We have recently reported PGRN expression in islets and tumors developed in an MEN1 transgenic mouse. Here we sought to investigate PGRN expression and regulation after exposure to hypoxia as well as its effects on pancreatic islet cells and neuroendocrine tumors (NETs) in MEN1(+/−) mice. METHODS: Gene and protein expression were analyzed by quantitative polymerase chain reaction, immunohistochemistry, and Western blot. We also investigated PGRN expression in samples from patients carrying pancreatic NETs associated or not with the multiple endocrine neoplasia 1 syndrome, using enzyme-linked immunosorbent assay and immunohistochemistry analysis. RESULTS: Progranulin is upregulated in tumors and islets of the MEN1 mouse as well as in the serum of patients with pancreatic NETs associated with glucagonoma syndrome. In normal mice islets and pancreatic tumors, PGRN expression was strongly potentiated by hypoxia. Progranulin promotes cell proliferation in islet cells and ßTC-6 cells, a process paralleled by activation of the mitogen-activated protein kinase signaling cascade. CONCLUSIONS: Our findings identify PGRN as an effective inducer of pancreatic islet cell proliferation and a possible important factor for pancreatic endocrine tumor development.


Subject(s)
Cell Proliferation/genetics , Intercellular Signaling Peptides and Proteins/genetics , Islets of Langerhans/metabolism , Neuroendocrine Tumors/genetics , Pancreatic Neoplasms/genetics , Proto-Oncogene Proteins/genetics , Animals , Blotting, Western , Cell Hypoxia , Cell Line , Cells, Cultured , Disease Models, Animal , Gene Expression Regulation, Neoplastic , Glucagonoma/genetics , Glucagonoma/metabolism , Granulins , Humans , Immunohistochemistry , Intercellular Signaling Peptides and Proteins/blood , Intercellular Signaling Peptides and Proteins/metabolism , MAP Kinase Signaling System/genetics , Mice, Knockout , Neuroendocrine Tumors/metabolism , Neuroendocrine Tumors/pathology , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Progranulins , Proto-Oncogene Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Up-Regulation
11.
Regen Ther ; 3: 68-74, 2016 Mar.
Article in English | MEDLINE | ID: mdl-31245475

ABSTRACT

Cell surface engineering using single-stranded DNA-poly(ethylene glycol)-conjugated phospholipid (ssDNA-PEG-lipid) is useful for inducing cell-cell attachment two and three dimensionally. In this review, we summarize our recent techniques for cell surface engineering and their applications to islet transplantation. Because any DNA sequence can be immobilized onto the cell surface by hydrophobic interactions between ssDNA-PEG-lipid and the cellular membrane without impairing cell function, a cell-cell hybrid can be formed through the DNA hybridization. With this technique, it would be possible to create three-dimensional hybrid structures of pancreatic islets coated with various accessory cells, such as patients' own cells, mesenchymal and adipose-derived stem cells, endothelial progenitor cells, neural crest stem cells or regulatory T cells, which might significantly improve the outcome of islet transplantation in diabetic patients.

12.
Ups J Med Sci ; 120(3): 169-80, 2015.
Article in English | MEDLINE | ID: mdl-25854824

ABSTRACT

BACKGROUND: Pancreatic or islet fibrosis is often associated with activated pancreatic stellate cells (PSCs). PSCs are considered not only to promote fibrosis, but also to be associated with glucose intolerance in some diseases. We therefore evaluated morphological and functional relationships between islets and PSCs in the normal mouse pancreas and transplanted islets. METHODS: Immunohistochemistry was used to map the presence of PSCs in the normal mouse pancreas and islets implanted under the renal capsule. We isolated and cultured mouse PSCs and characterized them morphologically by immunofluorescence staining. Furthermore, we measured their cytokine production and determined their effects on insulin release from simultaneously cultured islets. RESULTS: PSCs were scattered throughout the pancreas, with occasional cells within the islets, particularly in the islet capsule. In islet transplants they were found mainly in the graft periphery. Cultured PSCs became functionally activated and produced several cytokines. Throughout the culture period they linearly increased their production of interleukin-6 and mammalian keratinocyte-derived chemokine. PSC cytokine production was not affected by acute hyperglycemia. Syngeneic islets co-cultured with PSCs for 24-48 h increased their insulin release and lowered their insulin content. However, short-term insulin release in batch-type incubations was unaffected after 48 h of co-culture. Increased islet cell caspase-3 activation and a decreased islet cell replication were consistently observed after co-culture for 2 or 7 days. CONCLUSION: Activated PSCs may contribute to impaired islet endocrine function seen in exocrine pancreatitis and in islet fibrosis associated with some cases of type 2 diabetes.


Subject(s)
Islets of Langerhans/physiopathology , Pancreatic Stellate Cells/metabolism , Animals , Biomarkers/metabolism , Cells, Cultured , Cytokines/metabolism , Diabetes Mellitus, Type 2/metabolism , Hyperglycemia/metabolism , Immunohistochemistry , Insulin/metabolism , Islets of Langerhans/metabolism , Islets of Langerhans Transplantation , Male , Mice , Mice, Inbred C57BL , Real-Time Polymerase Chain Reaction
13.
Mol Immunol ; 67(1): 101-7, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25746915

ABSTRACT

Abundant reports have shown that there is a strong relationship between C3 and C3a-desArg levels, adipose tissue, and risk factors for cardiovascular disease, metabolic syndrome and diabetes. The data indicate that complement components, particularly C3, are involved in lipid metabolism. The C3 fragment, C3a-desArg, functions as a hormone that has insulin-like effects and facilitates triglyceride metabolism. Adipose tissue produces and regulates the levels of complement components, which promotes generation of inflammatory initiators such as the anaphylatoxins C3a and C5a. The anaphylatoxins trigger a cyto/chemokine response in proportion to the amount of adipose tissue present, and induce inflammation and mediate metabolic effects such as insulin resistance. These observations support the concept that complement is an important participant in lipid metabolism and in obesity, contributing to the metabolic syndrome and to the low-grade inflammation associated with obesity.


Subject(s)
Adipose Tissue/immunology , Cardiovascular Diseases/immunology , Complement C3a/immunology , Diabetes Mellitus/immunology , Lipid Metabolism/immunology , Metabolic Syndrome/immunology , Obesity/immunology , Adipose Tissue/metabolism , Adipose Tissue/pathology , Apolipoproteins/genetics , Apolipoproteins/immunology , Apolipoproteins/metabolism , Cardiovascular Diseases/genetics , Cardiovascular Diseases/metabolism , Cardiovascular Diseases/pathology , Complement C3a/genetics , Complement C3a/metabolism , Complement C5a/genetics , Complement C5a/immunology , Complement C5a/metabolism , Diabetes Mellitus/genetics , Diabetes Mellitus/metabolism , Diabetes Mellitus/pathology , Gene Expression Regulation , Humans , Insulin Resistance/immunology , Metabolic Syndrome/genetics , Metabolic Syndrome/metabolism , Metabolic Syndrome/pathology , Obesity/genetics , Obesity/metabolism , Obesity/pathology , Receptors, Complement/genetics , Receptors, Complement/immunology , Receptors, Complement/metabolism , Risk Factors , Triglycerides/genetics , Triglycerides/immunology , Triglycerides/metabolism
14.
Microvasc Res ; 97: 124-9, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25446368

ABSTRACT

The blood perfusion of pancreatic islets is regulated independently from that of the exocrine pancreas, and is of importance for multiple aspects of normal islet function, and probably also during impaired glucose tolerance. Single islet blood flow has been difficult to evaluate due to technical limitations. We therefore adapted a hydrogen gas washout technique using microelectrodes to allow such measurements. Platinum micro-electrodes monitored hydrogen gas clearance from individual endogenous and transplanted islets in the pancreas of male Lewis rats and in human and mouse islets implanted under the renal capsule of male athymic mice. Both in the rat endogenous pancreatic islets as well as in the intra-pancreatically transplanted islets, the vascular conductance and blood flow values displayed a highly heterogeneous distribution, varying by factors 6-10 within the same pancreas. The blood flow of human and mouse islet grafts transplanted in athymic mice was approximately 30% lower than that in the surrounding renal parenchyma. The present technique provides unique opportunities to study the islet vascular dysfunction seen after transplantation, but also allows for investigating the effects of genetic and environmental perturbations on islet blood flow at the single islet level in vivo.


Subject(s)
Hydrogen , Islets of Langerhans Transplantation , Islets of Langerhans/blood supply , Islets of Langerhans/surgery , Rheology/methods , Animals , Blood Flow Velocity , Equipment Design , Feasibility Studies , Gases , Heterografts , Humans , Hydrogen/blood , Laser-Doppler Flowmetry , Male , Mice, Inbred C57BL , Mice, Nude , Microelectrodes , Microspheres , Predictive Value of Tests , Rats, Inbred Lew , Regional Blood Flow , Rheology/instrumentation , Time Factors
15.
Am J Pathol ; 182(6): 2355-67, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23583653

ABSTRACT

Vascular therapeutic targeting requires thorough evaluation of the mechanisms activated in the specific context of each particular tumor type. We highlight structural, molecular, and functional microvascular aberrations contributing to development and maintenance of pancreatic neuroendocrine tumors (NETs), with special reference to multiple endocrine neoplasia 1 (MEN1) syndrome, using a Men1 mouse model. Tissue samples were analyzed by immunofluorescence to detect vessel density and pericyte distribution within the endocrine pancreas; expression of angiogenic factors was assessed by immunohistochemistry and quantitative real-time PCR in isolated islets and adenomas cultured under normoxic or hypoxic conditions. The increased vascular density of pancreatic NETs developed in Men1 mice was paralleled by an early and extensive redistribution of pericytes within endocrine tissue. These morphological alterations are supported by, and in some cases preceded by, fine-tuned variations in expression of several angiogenic regulators and are further potentiated by hypoxia. By combining two novel ex vivo and in vivo single-islet and tumor perfusion techniques, we demonstrated that both vascular reactivity and blood perfusion of tumor arterioles are significantly altered in response to glucose and L-nitro-arginine methyl ester. Our findings unravel multiple potential molecular and physiological targets differentially activated in the endocrine pancreas of Men1 mice and highlight the need for in-depth functional studies to fully understand the contribution of each component to development of pancreatic NETs in MEN1 syndrome.


Subject(s)
Islets of Langerhans/blood supply , Multiple Endocrine Neoplasia Type 1/blood supply , Neovascularization, Pathologic/pathology , Pancreatic Neoplasms/blood supply , Angiogenesis Inducing Agents/metabolism , Animals , Arterioles/physiology , Disease Models, Animal , Gene Expression Regulation, Neoplastic , Islets of Langerhans/metabolism , Mice , Mice, Knockout , Microvessels/pathology , Multiple Endocrine Neoplasia Type 1/metabolism , Multiple Endocrine Neoplasia Type 1/pathology , Neoplasm Proteins/metabolism , Neovascularization, Pathologic/genetics , Neovascularization, Pathologic/metabolism , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Pericytes/pathology , Proto-Oncogene Proteins/metabolism , RNA, Messenger/genetics
16.
Pancreas ; 41(8): 1263-71, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22617710

ABSTRACT

OBJECTIVE: The objective of this study was to evaluate the effects of exogenously administered lactate and pyruvate on blood perfusion in endogenous and transplanted islets. METHODS: Anesthetized Wistar-Furth rats were given lactate or pyruvate intravenously, and regional blood perfusion was studied 3 or 30 minutes later with a microsphere technique. Separate rats received a 30-minute infusion of pyruvate or lactate into the portal vein before blood flow measurements. We also administered these substances to islet-implanted rats 4 weeks after transplantation and measured graft blood flow with laser Doppler flowmetry. The expression of monocarboxylate transporter 1 and lactate dehydrogenase A was analyzed. RESULTS: The expression of monocarboxylate transporter 1 and lactate dehydrogenase A was markedly up-regulated in transplanted as compared with endogenous islets. Administration of pyruvate, but not lactate, increased mesenteric blood flow after 3 minutes. Pyruvate decreased mesenteric blood flow after 30 minutes, whereas lactate decreased only islet blood flow. These responses were absent in transplanted animals. A continuous intraportal infusion of lactate or pyruvate increased selectively islet blood flow but did not affect blood perfusion of transplanted islets. CONCLUSIONS: Lactate and pyruvate affect islet blood flow through effects mediated by interactions between the liver and the nervous system. Such a response can help adjust the release of islet hormones during excess substrate concentrations.


Subject(s)
Islets of Langerhans Transplantation , Islets of Langerhans/blood supply , Lactic Acid/administration & dosage , Pyruvic Acid/administration & dosage , Animals , Blood Glucose/metabolism , Insulin/blood , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Isoenzymes/biosynthesis , L-Lactate Dehydrogenase/biosynthesis , Lactate Dehydrogenase 5 , Male , Mesentery/blood supply , Mesentery/drug effects , Microspheres , Monocarboxylic Acid Transporters/biosynthesis , Rats , Rats, Inbred WF , Regional Blood Flow/drug effects , Regional Blood Flow/physiology , Symporters/biosynthesis , Up-Regulation
17.
Endocrinology ; 153(6): 2588-98, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22492302

ABSTRACT

Individuals carrying heterozygous (hz) MEN1 (Multiple Endocrine Neoplasia Syndrome Type 1) germ line mutations develop endocrine tumors as a result of somatic loss of the wild-type (wt) allele. However, endocrine cell proliferation has been observed despite wt allele retention, indicating haploinsufficiency. To study downstream molecular effects of the hz haplotype, a germ line Men1 hz mouse model was used to explore differences in global endocrine pancreatic gene expression. Because islet cells of 5-wk-old hz mice express Menin from the retained wt Men1 allele, these were isolated after collagenase digestion of the pancreas, and used for global gene expression array. Wild-type littermates were used for comparison. Array findings were corroborated by quantitative PCR, Western blotting, in situ proximity ligation assay, and immunohistochemistry. The hz islets show increased proliferation: the Ki-67 index was twice as high as in wt islets (3.48 vs. 1.74%; P = 0.024). The microarray results demonstrated that several genes were differentially expressed. Some selected genes were studied on the protein level, e.g. the cytoskeletal regulator myristoylated alanine-rich protein kinase C substrate (Marcks) was significantly less expressed in hz islets, using in situ proximity ligation assay and Western blotting (P < 0.001 and P < 0.01, respectively). Further, gene ontology analysis showed that genes with higher mRNA expression in the hz endocrine pancreas were associated with e.g. chromatin maintenance and apoptosis. Lower mRNA was observed for genes involved in growth factor binding. In conclusion, despite retained Menin expression, proliferation was accelerated, and numerous genes were differentially expressed in the endocrine pancreas of 5-wk-old hz Men1 mice, corroborating the hypothesis that MEN1 is a haploinsufficient suppressor.


Subject(s)
Cell Proliferation , Gene Expression Profiling , Islets of Langerhans/metabolism , Proto-Oncogene Proteins/genetics , Animals , Blotting, Western , Gene Expression Regulation, Neoplastic , Haploinsufficiency , Heterozygote , Immunohistochemistry , Islets of Langerhans/pathology , Ki-67 Antigen/metabolism , Mice , Mice, Knockout , Multiple Endocrine Neoplasia Type 1/genetics , Multiple Endocrine Neoplasia Type 1/metabolism , Oligonucleotide Array Sequence Analysis , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Proto-Oncogene Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction
18.
Am J Physiol Endocrinol Metab ; 297(5): E1067-77, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19706790

ABSTRACT

The transcription factor nuclear factor (NF)-κB is known to modulate rates of apoptosis and may therefore play a role in the increased ß-cell death that occurs in type 1 and type 2 diabetes. The aim of the present investigation was to study the expression of NF-κB subunits in human islet cells and whether overexpression of the NF-κB subunit c-Rel affects islet cell survival. We detected expression of p65, Rel-B, p50, p105, p52, and the ribosomal protein S3 (rpS3) in human islet cells. Among these, only p65 and rpS3 were translocated from the cytosolic to the nuclear fraction in response to cytokines. Interestingly, rpS3 participated in p65 binding to the κB-element in gel shift analysis experiments. We observed cytoplasmic c-Rel expression in vivo in 6J mice, and signs of nuclear translocation in ß-cells of infiltrated nonobese diabetic islets. Human islet cells were also dispersed by trypsin treatment and transduced with a c-Rel adenoviral vector. This resulted in increased expression of c-Rel and inhibitory factor κB, increased κB-binding activity, and augmented protein levels of Bcl-X(L,) c-IAP2, and heat shock protein 72. c-Rel expression in human islet cells protected against cytokine-induced caspase 3 activation and cell death. c-Rel protected also against streptozotocin- and H(2)O(2)-induced cell death, in both intact rat islets and human islet cells. We conclude that rpS3 participates in NF-κB signaling and that a genetic increase in the activity of the NF-κB subunit c-Rel results in protection against cell death in human islets.


Subject(s)
Islets of Langerhans/drug effects , NF-kappa B/biosynthesis , NF-kappa B/physiology , Protein Subunits/biosynthesis , Protein Subunits/physiology , Adenoviridae/genetics , Animals , Apoptosis Regulatory Proteins/metabolism , Blotting, Western , Cell Death/physiology , Cell Survival/physiology , Coloring Agents , Electrophoretic Mobility Shift Assay , Female , Gene Expression/physiology , Genetic Vectors , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Inbred NOD , Microscopy, Confocal , Nuclear Proteins/biosynthesis , Nuclear Proteins/isolation & purification , Perfusion , Rats , Rats, Sprague-Dawley , Tetrazolium Salts , Thiazoles , Transduction, Genetic
19.
Mol Cell Endocrinol ; 299(2): 163-71, 2009 Feb 27.
Article in English | MEDLINE | ID: mdl-19084046

ABSTRACT

In view of the central role of preadipocyte factor-1, adiponectin and leptin in white adipose tissue function, the aim of the present study was to analyze the mRNA expression of these proteins and of the inflammatory markers interleukin-6 and tumor necrosis factor-alpha in visceral and subcutaneous fat pads of rats with different metabolic disorders. We demonstrated highly divergent expression of preadipocyte factor-1, upregulated expression of adiponectin, interleukin-6 and TNF-alpha mRNA in adipose tissues of the diabetic Goto Kakizaki rat compared to the obese Zucker rat. This was correlated to an increased number of large adipocytes and serum levels of adiponectin. Furthermore, in all four strains studied (as above plus Wistar Furth and Zucker Lean), significant heterogeneity was evident in adipokine expression within specific adipose tissues previously defined as belonging to the visceral or subcutaneous fat depots. These results suggest that significantly increased levels of inflammation and redistribution of adipocyte size are mechanisms contributing to the development of type 2 diabetes in the GK rat.


Subject(s)
Adiponectin/metabolism , Adipose Tissue/metabolism , Intercellular Signaling Peptides and Proteins/metabolism , Leptin/metabolism , Membrane Proteins/metabolism , Adipocytes/cytology , Adipocytes/metabolism , Adiponectin/genetics , Animals , Blood Glucose , Body Weight , Cell Size , Gene Expression Regulation , Insulin/blood , Intercellular Signaling Peptides and Proteins/genetics , Interleukin-6/genetics , Interleukin-6/metabolism , Leptin/genetics , Membrane Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Zucker , Reverse Transcriptase Polymerase Chain Reaction , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism
20.
J Liposome Res ; 17(2): 49-62, 2007.
Article in English | MEDLINE | ID: mdl-17613696

ABSTRACT

Cationic lipid/DNA-complexes have been widely used as gene transfer vectors because they are less toxic and immunogenic than viral vectors. The aim of the present study was to improve and characterize lipofection of an insulin-producing cell line. We compared the transfection efficiency of seven commercially available lipid formulations (Lipotaxi, SuperFect, Fugene, TransFast, Dosper, GenePORTER and LipofectAMINE) by flow cytometry analysis of GFP-expression. In addition, we have determined the influences of centrifugation, serum and a nuclear localization signal peptide on the lipofection efficiency. We observed that two lipid formulations, GenePORTER and LipofectAMINE, were able to promote efficient gene transfer in RINm5F cells. However, GenePORTER exhibited the important advantage of being able to transfect cells in the presence of serum and with less cytotoxicity than LipofectAMINE. LipofectAMINE-induced RINm5F cell death could partially be counteracted by TPA, forskolin or fumonisin beta(1). Finally, both centrifugation and a nuclear localization signal peptide increased transfection efficiency.


Subject(s)
Gene Expression , Genetic Vectors/chemistry , Lipids/chemistry , Transfection/methods , Animals , Carcinogens/pharmacology , Cell Death/drug effects , Cell Line , Colforsin/pharmacology , Enzyme Inhibitors/pharmacology , Fumonisins/pharmacology , Green Fluorescent Proteins/biosynthesis , Green Fluorescent Proteins/genetics , Insulin/metabolism , Insulin Secretion , Rats , Tetradecanoylphorbol Acetate/pharmacology
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