80 research outputs found
Pore ordering in mesoporous matrices induced by different directing agents
Mesoporous silica particles of MCM
-
41 type were synthesized by sol
-
gel method fr
om
tetraethyl orthosilicate (TEOS) in
2
-
methoxyethanol
and
deionized water mixture in
base
conditions at room temperature. Ammonia or sodium hydroxides were used as catalysts and
cetyl
-
trimethylammonium bromide (CTAB)
and
n
-
dodecyl
-
trimethylammonium bromid
e
(DTAB) as structure directing agents. The porosities and the ordered structure have been
analyzed using transmission and scanning electron microscopy, small angle neutron and X
-
ray diffraction, nitrogen adsorption, thermal analysis and FTIR spectroscopy.
The samples
consist of spherical particles of sub
-
micrometer size, with radially arranged pores. The
comparison of the effect of the different surfactants and catalysts shows that by varying the
surfactant type and their proportion, the pore sizes can be
controlled. As compared to the
commonly used ammonia catalyst, the use of NaOH as catalyst results in a much smaller
porosity of the as
-
prepared materials. These materials are not resisting to the heat treatment at
700 ºC used for the template removal, and
the ordered porous structure is completely lost.
Keywords:
mesoporous silica, MCM
-
41, hexadecyl
-
trimethylammonium bromide, dodecyl
-
trimethyl ammonium bromide
Hepatoblast and mesenchymal cell-specific gene-expression in fetal rat liver and in cultured fetal rat liver cells
The aim of this study was to determine whether passaged rat fetal liver cells are functional hepatoblasts. Hepatocyte/hepatoblast- and liver myofibroblast-gene-expressions were studied in adult and fetal rat liver tissues as well as in primary and passaged cultures of isolated rat fetal liver cells at both the mRNA and protein level. Desmin- and Alpha-Smooth Muscle Actin (SMA)-positive cells were located in the walls of liver vessels, whereas Desmin-positive/SMA-negative cells were distributed within the liver parenchyma. Primary cultures contained Prox1-positive hepatoblasts, Desmin/SMA-positive myofibroblasts and only a few Desmin-positive/SMA-negative cells. Albumin and alpha-fetoprotein (AFP) could be detected in the primary cultures and to a lesser extent after the first passage. The number of Desmin-positive/SMA-negative cells decreased with successive passage, such that after the second passage, only Desmin/SMA-positive cells could be detected. SMA-gene-expression increased during the passages, suggesting that myofibroblasts become the major cell population of fetal liver cell cultures over time. This observation needs to be taken into account, should passaged fetal liver cells be used for liver cell transplantation. Moreover it contradicts the concept of epithelial-mesenchymal transformation and suggests rather that selective overgrowth of mesenchymal cells occurs in culture
Prevention of Neural-Tube Defects with Periconceptional Folic Acid, Methylfolate, or Multivitamins?
Background/Aims: To review the main results of intervention trials which showed the efficacy of periconceptional folic acid-containing multivitamin and folic acid supplementation in the prevention of neural-tube defects (NTD). Methods and Results: The main findings of 5 intervention trials are known: (i) the efficacy of a multivitamin containing 0.36 mg folic acid in a UK nonrandomized controlled trial resulted in an 83-91% reduction in NTD recurrence, while the results of the Hungarian (ii) randomized controlled trial and (iii) cohort-controlled trial using a multivitamin containing 0.8 mg folic acid showed 93 and 89% reductions in the first occurrence of NTD, respectively. On the other hand, (iv) another multicenter randomized controlled trial proved a 71% efficacy of 4 mg folic acid in the reduction of recurrent NTD, while (v) a public health-oriented Chinese-US trial showed a 41-79% reduction in the first occurrence of NTD depending on the incidence of NTD. Conclusions: Translational application of these findings could result in a breakthrough in the primary prevention of NTD, but so far this is not widely applied in practice. The benefits and drawbacks of 4 main possible uses of periconceptional folic acid/multivitamin supplementation, i.e. (i) dietary intake, (ii) periconceptional supplementation, (iii) flour fortification, and (iv) the recent attempt for the use of combination of oral contraceptives with 6S-5-methytetrahydrofolate (methylfolate), are discussed. Obviously, prevention of NTD is much better than the frequent elective termination of pregnancies after prenatal diagnosis of NTD fetuses
Remodeling of extracellular matrix by normal and tumor-associated fibroblasts promotes cervical cancer progression
Background:
Comparison of tissue microarray results of 29 cervical cancer and 27 normal cervix tissue samples
using immunohistochemistry revealed considerable reorganization of the fibrillar stroma of these tumors.
Preliminary densitometry analysis of laminin-1,
α
-smooth muscle actin (SMA) and fibronectin immunostaining
demonstrated 3.8-fold upregulation of laminin-1 and 5.2-fold increase of SMA in the interstitial stroma, indicating
that these proteins and the activated fibroblasts play important role in the pathogenesis of cervical cancer. In the
present work we investigated the role of normal and tumor-associated fibroblasts.
Methods:
In vitro
models were used to throw light on the multifactorial process of tumor-stroma interaction, by
means of studying the cooperation between tumor cells and fibroblasts. Fibroblasts from normal cervix and cervical
cancers were grown either separately or in co-culture with CSCC7 cervical cancer cell line. Changes manifest in
secreted glycoproteins, integrins and matrix metallo-proteases (MMPs) were explored.
Results:
While normal fibroblasts produced components of interstitial matrix and TGF-
β
1 that promoted cell
proliferation, cancer-associated fibroblasts (CAFs) synthesized ample amounts of laminin-1. The following results
support the significance of laminin-1 in the invasion of CSCC7 cells: 1.) Tumor-associated fibroblasts produced more
laminin-1 and less components of fibrillar ECM than normal cells; 2.) The production of laminin chains was further
increased when CSCC7 cells were grown in co-culture with fibroblasts; 3.) CSCC7 cells were capable of increasing
their laminin production; 4.) Tumor cells predominantly expressed integrin
α
6
β
4 laminin receptors and migrated
towards laminin. The integrin profile of both normal and tumor-associated fibroblasts was similar, expressing receptors
for fibronectin, vitronectin and osteopontin. MMP-7 secreted by CSCC7 cells was upregulated by the presence of
normal fibroblasts, whereas MMP-2 produced mainly by fibroblasts was activated in the presence of CSCC7 cells.
Conclusions:
Our results indicate that in addition to degradation of the basement membrane, invasion of cervical
cancer is accomplished by the remodeling of the interstitial stroma, which process includes decrease and partial replacement of fibronectin and collagens by a laminin-rich matrix
Effect of clinical signs, endocrinopathies, timing of surgery, hyperlipidemia, and hyperbilirubinemia on outcome in dogs with gallbladder mucocele
Gallbladder mucocele (GBM) is a common extra-hepatic biliary syndrome in dogs with death rates ranging from 7 to 45%. Therefore, the aim of this study was to identify the association of survival with variables that could be utilized to improve clinical decisions. A total of 1194 dogs with a gross and histopathological diagnosis of GBM were included from 41 veterinary referral hospitals in this retrospective study. Dogs with GBM that demonstrated abnormal clinical signs had significantly greater odds of death than subclinical dogs in a univariable analysis (OR, 4.2; 95% CI, 2.14–8.23; P < 0.001). The multivariable model indicated that categorical variables including owner recognition of jaundice (OR, 2.12; 95% CI, 1.19–3.77; P = 0.011), concurrent hyperadrenocorticism (OR 1.94; 95% CI, 1.08–3.47; P = 0.026), and Pomeranian breed (OR, 2.46; 95% CI 1.10–5.50; P = 0.029) were associated with increased odds of death, and vomiting was associated with decreased odds of death (OR, 0.48; 95% CI, 0.30–0.72; P=0.001). Continuous variables in the multivariable model, total serum/plasma bilirubin concentration (OR, 1.03; 95% CI, 1.01– 1.04; P < 0.001) and age (OR, 1.17; 95% CI, 1.08–1.26; P < 0.001), were associated with increased odds of death. The clinical utility of total serum/plasma bilirubin concentration as a biomarker to predict death was poor with a sensitivity of 0.61 (95% CI, 0.54–0.69) and a specificity of 0.63 (95% CI, 0.59–0.66). This study identified several prognostic variables in dogs with GBM including total serum/plasma bilirubin concentration, age, clinical signs, concurrent hyperadrenocorticism, and the Pomeranian breed. The presence of hypothyroidism or diabetes mellitus did not impact outcome in this study
Expression of ECM proteins fibulin-1 and -2 in acute and chronic liver disease and in cultured rat liver cells
Fibulin-2 has previously been considered as a marker to distinguish rat liver myofibroblasts from hepatic stellate cells. The function of other fibulins in acute or chronic liver damage has not yet been investigated. The aim of this study has been to evaluate the expression of fibulin-1 and -2 in models of rat liver injury and in human liver cirrhosis. Their cellular sources have also been investigated. In normal rat liver, fibulin-1 and -2 were both mainly present in the portal field. Fibulin-1-coding transcripts were detected in total RNA of normal rat liver, whereas fibulin-2 mRNA was only detected by sensitive, real-time quantitative polymerase chain reaction. In acute liver injury, the expression of fibulin-1 was significantly increased (17.23-fold after 48 h), whereas that of fibulin-2 was not modified. The expression of both fibulin-1 and -2 was increased in experimental rat liver cirrhosis (19.16- and 26.47-fold, respectively). At the cellular level, fibulin-1 was detectable in hepatocytes, “activated” hepatic stellate cells, and liver myofibroblasts (2.71-, 122.65-, and 469.48-fold over the expression in normal rat liver), whereas fibulin-2 was restricted to liver myofibroblasts and was regulated by transforming growth factor beta-1 (TGF-β1) in 2-day-old hepatocyte cultures and in liver myofibroblasts. Thus, fibulin-1 and -2 respond differentially to single and repeated damaging noxae, and their expression is differently present in liver cells. Expression of the fibulin-2 gene is regulated by TGF-β1 in liver myofibroblasts
Multiple SARS-CoV-2 Introductions Shaped the Early Outbreak in Central Eastern Europe: Comparing Hungarian Data to a Worldwide Sequence Data-Matrix
Severe Acute Respiratory Syndrome Coronavirus 2 is the third highly pathogenic human coronavirus in history. Since the emergence in Hubei province, China, during late 2019, the situation evolved to pandemic level. Following China, Europe was the second epicenter of the pandemic. To better comprehend the detailed founder mechanisms of the epidemic evolution in Central-Eastern Europe, particularly in Hungary, we determined the full-length SARS-CoV-2 genomes from 32 clinical samples collected from laboratory confirmed COVID-19 patients over the first month of disease in Hungary. We applied a haplotype network analysis on all available complete genomic sequences of SARS-CoV-2 from GISAID database as of 21 April 2020. We performed additional phylogenetic and phylogeographic analyses to achieve the recognition of multiple and parallel introductory events into our region. Here, we present a publicly available network imaging of the worldwide haplotype relations of SARS-CoV-2 sequences and conclude the founder mechanisms of the outbreak in Central-Eastern Europe
Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020
We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe
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