scholarly journals In vitro and in vivoactivity of the chloroaryl-substituted imidazole viniconazole againstTrypanosoma cruzi

Parasitology ◽  
2013 ◽  
Vol 141 (3) ◽  
pp. 367-373 ◽  
Author(s):  
CRISTIANE FRANÇA DA SILVA ◽  
DENISE DA GAMA JAEN BATISTA ◽  
MARCOS MEUSER BATISTA ◽  
JESSICA LIONEL ◽  
ERICA RIPOLL HAMMER ◽  
...  
Keyword(s):  
Protozoan Parasite ◽  
Cellular Damage ◽  
Large Numbers ◽  
Autophagic Process ◽  
Time Of Administration ◽  
Ultrastructural Findings ◽  
Alternative Drugs ◽  
Intracellular Protozoan Parasite

SUMMARYChagas disease (CD) is caused by the intracellular protozoan parasiteTrypanosoma cruziand affects more than 10 million people in poor areas of Latin America. There is an urgent need for alternative drugs with better safety, broader efficacy, lower costs and shorter time of administration. Thus the biological activity of viniconazole, a chloroaryl-substituted imidazole was investigated usingin vitroandin vivoscreening models ofT. cruziinfection. Ultrastructural findings demonstrated that the most frequent cellular damage was associated with plasma membrane (blebs and shedding events), Golgi (swelling aspects) and the appearance of large numbers of vacuoles suggesting an autophagic process. Our data demonstrated that although this compound is effective against bloodstream and intracellular forms (16 and 24 μm, respectively)in vitro, it does not presentin vivoefficacy. Due to the urgent need for novel agents againstT. cruzi, the screening of natural and synthetic products must be further supported with the aim of finding more selective and affordable drugs for CD.

Animal Models and Alternatives in the Quality Control of Vaccines: Are In Vitro Methods or In Vivo Methods the Scientific Equivalent of the Emperor's New Clothes?

1995 ◽  
Vol 23 (1) ◽  
pp. 61-73
Author(s):  
Coenraad Hendriksen ◽  
Johan van der Gun
Keyword(s):  
Quality Control ◽  
Test Methods ◽  
In Vitro Test ◽  
Large Numbers ◽  
Alternative Approach ◽  
Inactivated Vaccines ◽  
Vitro Test

In the quality control of vaccine batches, the potency testing of inactivated vaccines is one of the areas requiring very large numbers of animals, which usually suffer significant distress as a result of the experimental procedures employed. This article deals with the potency testing of diphtheria and tetanus toxoids, two vaccines which are used extensively throughout the world. The relevance of the potency test prescribed by the European Pharmacopoeia monographs is questioned. The validity of the potency test as a model for the human response, the ability of the test to be standardised, and the relevance of the test in relation to the quality of the product are discussed. It is concluded that the potency test has only limited predictive value for the antitoxin responses to be expected in recipients of these toxoids. An alternative approach for estimating the potency of toxoid batches is discussed, in which a distinction is made between estimation of the immunogenic potency of the first few batches obtained from a seed lot and monitoring the consistency of the quality of subsequent batches. The use of animals is limited to the first few batches. Monitoring the consistency of the quality of subsequent batches is based on in vitro test methods. Factors which hamper the introduction and acceptance of the alternative approach are considered. Finally, proposals are made for replacement, reduction and/or refinement (the Three Rs) in the use of animals in the routine potency testing of toxoids.

Activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum (Cestoda: Pseudophyllidea)

Parasitology ◽  
1981 ◽  
Vol 83 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Margaretha K. S. Gustafsson ◽  
Marianne C. Wikgren
Keyword(s):  
Neurosecretory Cells ◽  
Final Host ◽  
Fish Host ◽  
Neurosecretory System ◽  
Weak Reaction ◽  
Diphyllobothrium Dendriticum ◽  
Large Numbers ◽  
Short Times

SUMMARYThe activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum was studied following cultivation of plerocercoids for short times in vitro and in vivo. In the plerocercoid the neurosecretory cells gave a very weak reaction with paraldehyde fuchsin (PAF). After cultivation for 1 h large numbers of neurosecretory cells filled with PAF-positive granules were evident. The significance of the activation of the neurosecretory system during the transfer of the worm from the cold-blooded fish host to the warm-blooded final host is discussed.

Host oyster tissue extracts modulate in vitro protease expression and cellular differentiation in the protozoan parasite, Perkinsus marinus

Parasitology ◽  
2003 ◽  
Vol 126 (4) ◽  
pp. 293-302 ◽  
Author(s):  
E. A. MACINTYRE ◽  
C. G. EARNHART ◽  
S. L. KAATTARI
Keyword(s):  
Serine Proteases ◽  
Protozoan Parasite ◽  
Eastern Oyster ◽  
Defined Medium ◽  
Tissue Homogenate ◽  
Oyster Tissue ◽  
Perkinsus Marinus ◽  
Tissue Extracts

Perkinsus marinus is responsible for a chronic disease (Dermo) of the Eastern oyster, Crassostrea virginica. In order to simulate the in vivo environment more closely, a chemically defined medium (JL-ODRP-3) was supplemented with tissue homogenate extracts or plasma from oysters possessing varying degrees of susceptibility to P. marinus infection. In media supplemented with extracts from highly susceptible oysters (C. virginica), P. marinus cells secreted elevated amounts of a set of low molecular weight serine proteases (LMP: 30–45 kDa) as assessed by enhanced digestion within gelatin-substrate SDS–PAGE gels. Oyster species of low susceptibility (C. gigas and C. ariakensis) did not exhibit this ability to upregulate P. marinus LMP expression. Oyster extract supplementation also led to pronounced changes in P. marinus cellular morphology, such that the cells were comparable to those observed within naturally infected oysters.

scholarly journals ELECTRON MICROSCOPY OF PLASMA-CELL TUMORS OF THE MOUSE

1961 ◽  
Vol 9 (2) ◽  
pp. 369-381 ◽  
Author(s):  
D. F. Parsons ◽  
M. A. Bender ◽  
E. B. Darden ◽  
Guthrie T. Pratt ◽  
D. L. Lindsley
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Complex Structure ◽  
Granular Body ◽  
Virus Particles ◽  
Culture Cells ◽  
Large Numbers ◽  
Tumor Agent

The X5563 tumor has been grown in tissue culture. Cells similar to those of the original tumor migrated from the explant and attached to the glass walls of the culture vessels. Electron microscopy showed that large numbers of particles, similar in morphology to virus particles, were associated with these cells after 7 days of culture. The two principal types of particles found in the tumor in vivo appear to be present in vitro. Many more of these particles, however, were larger and showed a more complex structure. Whereas the particles were mainly localized inside endoplasmic reticulum or the Golgi zone in the tumors in vivo, in the tissue culture the majority of the particles were associated with the plasma membrane and were found outside of the cells. The relation of the particles to the granular body is discussed as well as a possible relation to the mammary tumor agent.

scholarly journals Development of a Phototoxicity Testing Strategy for Accurate Photosafety Evaluation of Pharmaceuticals Based on the Assessment of Possible Melanin-Binding Effects

2018 ◽  
Vol 37 (4) ◽  
pp. 296-307
Author(s):  
Jelle Reinen ◽  
Pieter van Sas ◽  
Ton van Huygevoort ◽  
Leticia Rubio ◽  
Kevin Scase ◽  
...  
Keyword(s):  
Cellular Damage ◽  
In Vivo Studies ◽  
Brown Norway ◽  
Albino Rats ◽  
Guidance Document ◽  
High Affinity ◽  
Drug Concentrations ◽  
Melanin Binding

Drug-induced phototoxicity occurs when drugs absorb natural sunlight, leading to chemical reactions causing cellular damage. Distribution to light-exposed tissues is critical and is enhanced by binding to melanin. The International Council on Harmonization S10 guidance document on photosafety evaluation of pharmaceuticals states that although nonpigmented skin tends to be more sensitive than pigmented skin, pigmented skin models should be considered for drugs that bind significantly to melanin. In this study, an in vitro melanin-binding assay was evaluated as prescreening tool for animal model selection. Binding of various structurally diverse phototoxic drugs to synthetic melanin was investigated in vitro and the high-affinity binder sparfloxacin (SPX), moderate-affinity binder 8-methoxypsoralen (8-MOP), and low-affinity binder pirfenidone (PIF) were selected for in vivo studies. Pigmented Brown Norway (BN) rats were compared with nonpigmented Wistar Albino rats to evaluate their sensitivity for the assessment of phototoxicity and skin concentrations of the drugs were measured. For SPX, the onset of phototoxic symptoms was faster for BN rats and drug concentrations were significantly higher in skin of BN rats. For 8-MOP, both models showed comparable sensitivity and skin concentrations did not differ. For the low-affinity binder PIF, no phototoxic effects were observed and skin concentrations in both models were similar. A combined in vitro/in vivo approach was developed that can be applied for accurate photosafety evaluation of pharmaceuticals based on the assessment of possible melanin-binding effects. In view of the presented data, the pigmented model could be considered for compounds showing a high-affinity binding capacity in vitro.

Potential Health Benefits Of A Pomegranate Extract, Rich In Phenolic Compounds, In Intestinal Inflammation

2021 ◽  
Vol 17 ◽  
Author(s):  
Marco Raffaele ◽  
Khaled Greish ◽  
Luca Vanella ◽  
Giuseppe Carota ◽  
Fatemah Bahman ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Molecular Mechanisms ◽  
Intestinal Inflammation ◽  
Inflammatory Marker ◽  
Experimental Models ◽  
Cellular Damage ◽  
Experimental Conditions ◽  
Potential Health

Background: Pomegranate is a fruit rich in bioactive compounds such as punicalagins, gallic acid, and ellagic acid derivatives. It has been widely used since ancient times in traditional medicine for a wide variety of diseases. It has been reported that bioactive compounds, such as polyphenols, are able to induce the expression of cytoprotective enzymes, including HO-1. The contribution of HO-1 activity to the prevention of intestinal inflammation has been shown in different models of Inflammatory bowel diseases (IBD). Objective: Aim of the present research was to investigate the molecular mechanisms involved in the beneficial effects of a pomegranate extract (PE), rich in bioactive compounds in intestinal inflammation. Methods: Caco-2 cells exposed to LPS and DSS induced colitis were chosen as convenient experimental models of intestinal inflammation. Results: Results obtained in our experimental conditions, showed that PE in vitro was able to induce HO-1 and to reduce cellular damage and oxidative stress through increase of GSH levels. Moreover, PE was able to decrease the pro-inflammatory marker IL-8 levels and to activate TIGAR pathway. The results obtained in vivo, in agreement with the data obtained in vitro, highlighted the ability of PE to reduce intestinal inflammation, preserve the colon length and histological features and reduce IL-6 levels compared to the DSS treated group. Conclusion: PE, rich in bioactive compounds, could contribute, as supportive therapy, to enhance the effects of the conventional therapeutic strategies to the management of IBD.

Infection with the intracellular protozoan parasite Theileria parva induces constitutively high levels of NF-kappa B in bovine T lymphocytes

1989 ◽  
Vol 9 (11) ◽  
pp. 4677-4686
Author(s):  
V Ivanov ◽  
B Stein ◽  
I Baumann ◽  
D A Dobbelaere ◽  
P Herrlich ◽  
...  
Keyword(s):  
T Cells ◽  
Phorbol Esters ◽  
Protozoan Parasite ◽  
Lymphoproliferative Disease ◽  
Host Cells ◽  
Specific Gene ◽  
Theileria Parva ◽  
Nf Kappa B ◽  
Intracellular Protozoan Parasite

The intracellular protozoan parasite Theileria parva causes a lymphoproliferative disease of T cells in cattle and uncontrolled lymphocyte proliferation in culture. We have identified and characterized in infected cells the transcriptional activator, NF-kappa B, whose recognition motifs have been identified in several gene enhancers important for lymphocyte-specific gene expression. NF-kappa B is normally constitutively activated in nuclear extracts derived from B cells and can be induced in T cells and nonlymphoid cells by phorbol esters. Theileria-infected lymphocytes contained constitutively high levels of activated NF-kappa B in nuclear fractions and inactive NF-kappa B in cytoplasmic fractions. The inactive cytoplasmic precursor could be activated by treatment of extracts with deoxycholate, which was shown previously to dissociate NF-kappa B from an inhibitor, I kappa B. Treatment of lymphocyte extracts with 3 mM GTP stimulated NF-kappa B binding to its recognition motif in vitro, thereby distinguishing it from a related nuclear factor, H2-TF1. Selective killing of the parasite, which left the host cells intact, resulted in a rapid loss of NF-kappa B from the nuclear fractions and a slower loss from the cytoplasmic fractions. In parasitized cells, NF-kappa B could not be further stimulated by treatment with 12-O-tetradecanoylphorbol-13-acetate whereas in cells treated to remove the parasite, this compound stimulated elevated levels of NF-kappa B. We propose that high levels of activated NF-kappa B are maintained by the presence of the parasite in infected T cells. Similarly, we propose that the high levels of inactive cytoplasmic precursor are a result of increased synthesis due to the presence of the parasite.

scholarly journals Assessing the Efficacy of Dietary Selenomethionine Supplementation in the Setting of Cardiac Ischemia/Reperfusion Injury

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 546 ◽  
Author(s):  
Leila Reyes ◽  
David P. Bishop ◽  
Clare L. Hawkins ◽  
Benjamin S. Rayner
Keyword(s):  
Cardiac Myocyte ◽  
Hypochlorous Acid ◽  
Ischemia Reperfusion Injury ◽  
Heart Function ◽  
Ischemia Reperfusion ◽  
Cytosolic Calcium ◽  
Cardiac Ischemia ◽  
Cellular Damage

Oxidative stress is a major hallmark of cardiac ischemia/reperfusion (I/R) injury. This partly arises from the presence of activated phagocytes releasing myeloperoxidase (MPO) and its production of hypochlorous acid (HOCl). The dietary supplement selenomethionine (SeMet) has been shown to bolster endogenous antioxidant processes as well as readily react with MPO-derived oxidants. The aim of this study was to assess whether supplementation with SeMet could modulate the extent of cellular damage observed in an in vitro cardiac myocyte model exposed to (patho)-physiological levels of HOCl and an in vivo rat model of cardiac I/R injury. Exposure of the H9c2 cardiac myoblast cell line to HOCl resulted in a dose-dependent increase in necrotic cell death, which could be prevented by SeMet supplementation and was attributed to SeMet preventing the HOCl-induced loss of mitochondrial inner trans-membrane potential, and the associated cytosolic calcium accumulation. This protection was credited primarily to the direct oxidant scavenging ability of SeMet, with a minor contribution arising from the ability of SeMet to bolster cardiac myoblast glutathione peroxidase (GPx) activity. In vivo, a significant increase in selenium levels in the plasma and heart tissue were seen in male Wistar rats fed a diet supplemented with 2 mg kg−1 SeMet compared to controls. However, SeMet-supplementation demonstrated only limited improvement in heart function and did not result in better heart remodelling following I/R injury. These data indicate that SeMet supplementation is of potential benefit within pathological settings where excessive HOCl is known to be generated but has limited efficacy as a therapeutic agent for the treatment of heart attack.

scholarly journals Platelet Alterations Caused by Antiplatelet Antibodies in the Circulation

1977 ◽  
Author(s):  
T. Nagasawa ◽  
B.K. Kim ◽  
M.G. Baldini
Keyword(s):  
Platelet Count ◽  
Specific Activity ◽  
Rabbit Model ◽  
Antiplatelet Antibodies ◽  
Large Numbers ◽  
Severe Reduction ◽  
Series Of Experiments ◽  
Specific Activities

It is known that antiplatelet antibodies cause loss of platelet cytoplasmic and granular contents in vitro. It is, however, unknown whether similar platelet changes occur in vivo, in the circulation, leading to destruction and phagocytosis of platelets in the R.E. system. To study this possibility a rabbit model was devised. Severe and stable thrombocytopenia was first produced in rabbits by one intravenous injection of Adriamycin. Large numbers of allogenic platelets labeled in vitro with 51Cr and 14C-serotonin were then infused to raise the circulating platelet count to 180-250 × 103/mm3. A dilute heteroimmune antiplatelet serum prepared in the guinea pig was infused intravenously and platelet samples were collected four times during the subsequent 30 minutes to 24 hours. Platelet hexokinase and β-glucuronidase, 14C-serotonin and 51Cr were measured. Within the first 60 min the specific activity of 51Cr in platelets decreased by 21%, 14C-serotonin declined by 30%, hexokinase by 5% and β-glucuronidase by 29%. During the subsequent 24 hours only 51Cr and hexokinase registered a mild decrease but 51C-serotonin and β-glucuronidase remained essentially unchanged. In a second series of experiments the effect of platelet alloantibodies was studied in rabbits previously immunized with allogenic platelets. The decline in the specific activities of the enzymes and 14C-serotonin was similar to that observed in animals treated with heteroimmune sera but loss of 51Cr was more severe. These results demonstrate that the platelets remaining in the circulation after the disappearance of the immediate effect of hetero- or alloantibodies were qualitatively altered with a severe reduction of their granular and cytoplasmic contents.

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