Penetration gland secretion by hexacanths of Hymenolepis diminuta

Parasitology ◽  
1974 ◽  
Vol 68 (3) ◽  
pp. 303-311 ◽  
Author(s):  
R. C. Lethbridge ◽  
M. F. Gijsbers
Keyword(s):  
Surface Membrane ◽  
Neutral Red ◽  
Hymenolepis Diminuta ◽  
Penetration Gland ◽  
Tissue Extracts ◽  
Time Period ◽  
Red Dye ◽  
Gland Material

The rate of expulsion of penetration gland material was determined from photomicrographs of Hymenolepis diminuta hexacanths stained with neutral red dye at intervals after hatching in vitro. Identical secretory rates were recorded for hexacanths incubated in either Tyrode's solution or Tyrode's solution plus an extract of the midgut of Tenebrio molitor. In both media the reduction in stained material observed in the glands after 135 min incubations was equivalent to that observed for hexacanths that had had opportunity to penetrate in vivo during the same time period. These results were interpreted as indicating that the in vivo secretory pattern was similar to that observed in vitro, and that chemical stimuli from the tissue extracts were not required to initiate secretion. Microdensitometric readings also demonstrated a quantitative decrease in dye within the glands as incubation time increased. Ultrastructural examination of the glands showed that their secretory inclusions were exported via ducts to the epithelial cytoplasm where they accumulated in discrete blebs enclosed by the surface membrane. These inclusion-filled, membrane-bounded blebs were apparently formed and released continuously until, after approximately 2 h, only a few inclusions remained in the penetration glands.

A Study on UV Filter Chemicals from Annex VII of European Union Directive 76/768/EEC, in the In Vitro 3T3 NRU Phototoxicity Test

1998 ◽  
Vol 26 (5) ◽  
pp. 679-708 ◽  
Author(s):  
Horst Spielmann ◽  
Michael Balls ◽  
Jack Dupuis ◽  
Wolfgang J. W. Pape ◽  
Odile de Silva ◽  
...  
Keyword(s):  
Neutral Red ◽  
Optimum Concentration ◽  
Alternative Methods ◽  
Uv Filter ◽  
Eu Directive ◽  
Optimum Concentration Range ◽  
The Impact ◽  
Positive Results

In 1996, the Scientific Committee on Cosmetology of DGXXIV of the European Commission asked the European Centre for the Validation of Alternative Methods to test eight UV filter chemicals from the 1995 edition of Annex VII of Directive 76/768/EEC in a blind trial in the in vitro 3T3 cell neutral red uptake phototoxicity (3T3 NRU PT) test, which had been scientifically validated between 1992 and 1996. Since all the UV filter chemicals on the positive list of EU Directive 76/768/EEC have been shown not to be phototoxic in vivo in humans under use conditions, only negative effects would be expected in the 3T3 NRU PT test. To balance the number of positive and negative chemicals, ten phototoxic and ten non-phototoxic chemicals were tested under blind conditions in four laboratories. Moreover, to assess the optimum concentration range for testing, information was provided on appropriate solvents and on the solubility of the coded chemicals. In this study, the phototoxic potential of test chemicals was evaluated in a prediction model in which either the Photoirritation Factor (PIF) or the Mean Photo Effect (MPE) were determined. The results obtained with both PIF and MPE were highly reproducible in the four laboratories, and the correlation between in vitro and in vivo data was almost perfect. All the phototoxic test chemicals provided a positive result at concentrations of 1μg/ml, while nine of the ten non-phototoxic chemicals gave clear negative results, even at the highest test concentrations. One of the UV filter chemicals gave positive results in three of the four laboratories only at concentrations greater than 100μg/ml; the other laboratory correctly identified all 20 of the test chemicals. An analysis of the impact that exposure concentrations had on the performance of the test revealed that the optimum concentration range in the 3T3 NRU PT test for determining the phototoxic potential of chemicals is between 0.1μg/ml and 10μg/ml, and that false positive results can be obtained at concentrations greater than 100μg/ml. Therefore, the positive results obtained with some of the UV filter chemicals only at concentrations greater than 100μg/ml do not indicate a phototoxic potential in vivo. When this information was taken into account during calculation of the overall predictivity of the 3T3 NRU PT test in the present study, an almost perfect correlation of in vitro versus in vivo results was obtained (between 95% and 100%), when either PIF or MPE were used to predict the phototoxic potential. The management team and participants therefore conclude that the 3T3 NRU PT test is a valid test for correctly assessing the phototoxic potential of UV filter chemicals, if the defined concentration limits are taken into account.

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.

Detection of Circulating Immune Complexes in the Sera of Rabbits with Experimental Syphilis: Possible Role in Immunoregulation

1980 ◽  
Vol 29 (2) ◽  
pp. 575-582
Author(s):  
Robert E. Baughn ◽  
Kenneth S. K. Tung ◽  
Daniel M. Musher
Keyword(s):  
Immune Complexes ◽  
Proteolytic Enzymes ◽  
Suppressor Cell ◽  
Suppressive Effect ◽  
Circulating Immune Complexes ◽  
Time Period ◽  
Infected Cells ◽  
Disseminated Disease

The in vivo and in vitro immunoglobulin G plaque-forming cell responses to sheep erythrocytes (SRBC) are nearly obliterated during disseminated syphilitic infection (3 to 8 weeks post-intravenous injection) in rabbits. Splenic and lymph node cells obtained from infected rabbits during this time period were capable of suppressing the normal in vitro responses of uninfected, SRBC-primed cells. Cell-free washings of cells from infected animals were also suppressive. This finding coupled with the fact that treatment of infected cells with proteolytic enzymes abrogated the suppressive effect constitute arguments against involvement of a specific suppressor cell population. The incidence of elevated levels of circulating immune complexes in the sera of rabbits with disseminated disease was also significantly different from that of uninfected controls or infected rabbits before the onset or after the regression of lesions. When added to cultures of lymphocytes from uninfected, SRBC-sensitized rabbits, sera containing complexes caused dose-related suppression of the in vitro immunoglobulin responses. Unlike immune complexes, no correlation was found between the presence of mucopolysaccharide materials and the stage of infection or the ability of serum to suppress the immunoglobulin responses to SRBC.

scholarly journals Biocompatibility Evaluation of Electrospun Scaffolds of Poly (L-Lactide) with Pure and Grafted Hydroxyapatite

2017 ◽  
Vol 58 (4) ◽  
Author(s):  
José Manuel Cornejo-Bravo ◽  
Luis Jesús Villarreal-Gómez ◽  
Ricardo Vera-Graziano ◽  
María Raquel Vega-Ríos ◽  
José Luis Pineda-Camacho ◽  
...  
Keyword(s):  
Bacterial Adhesion ◽  
Neutral Red ◽  
C2c12 Cells ◽  
Surrounding Tissue ◽  
Neutral Red Assay ◽  
Electrospun Scaffolds ◽  
Muscle Tissues ◽  
Hematoxylin Eosin

<p>The objective of this work was to evaluate the biocompatibility of scaffolds of poly(<em>L</em>-lactide) with pure and grafted hydroxyapatite, at various concentrations of reinforcement. The biocompatibility tests were carried out <em>in vivo </em>in Wistar rats by implanting the material into the subcutaneous and muscle tissues from 1 to 14 weeks and evaluating the surrounding tissue stained with hematoxylin-eosin. For <em>in vitro </em>assays, MTT and neutral red assay were used to evaluate any cytotoxicity in Mioblast Muscle C2C12 Cells (ATCC® CRL-1772™) and Bovine Coronary Artery Endothelial Cells (BCAEC); <em>Escherichia coli </em>and <em>Staphylococcus aureus </em>were used to evaluate bacterial adhesion. All variants of scaffolds provoked a mild inflammatory response, without showing necrosis. No evidence of cytotoxicity was presented in cell viability tests and good bacterial cell adhesion was visualized for all of the materials studied.</p>

scholarly journals Antiplasmodial profile of selected compounds from Malaria Box: in vitro evaluation, speed of action and drug combination studies

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Guilherme Eduardo de Souza ◽  
Renata Vieira Bueno ◽  
Juliana Oliveira de Souza ◽  
Camila Lima Zanini ◽  
Fábio Cardoso Cruz ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Inhibitory Activity ◽  
Similarity Index ◽  
Structural Similarity ◽  
Neutral Red ◽  
Molecular Target ◽  
Benzodiazepine Derivatives ◽  
Malaria Box

Abstract Background Artemisinin-based combination therapy (ACT) is used as the first-line treatment of uncomplicated malaria caused by the Plasmodium falciparum parasite and chloroquine-resistant Plasmodium vivax parasites. Evidence of resistance to ACT has been reported in Cambodia, and without new and effective anti-malarial agents, malaria burden and mortality will rise. Methods The used MolPrint 2D fingerprints and the Tanimoto similarity index were used to perform a structural similarity search within the Malaria Box collection to select diverse molecular scaffolds that are different from artesunate. Next, the inhibitory potency against the P. falciparum 3D7 strain (SYBR Green I inhibition assay) and the cytotoxicity against HepG2 cells (MTT and neutral red assays) were evaluated. Then, the speed of action, the combination profile of selected inhibitors with artesunate, and the P. berghei in vivo activity of the best compounds were assessed. Results A set of 11 structurally diverse compounds from the Malaria Box with a similarity threshold of less than 0.05 was selected and compared with artesunate. The in vitro inhibitory activity of each compound confirmed the reported potencies (IC50 values ranging from 0.005 to 1 µM). The cytotoxicity of each selected compound was evaluated and used to calculate the selectivity index (SI values ranging from 15.1 to 6100). Next, both the speed of action and the combination profile of each compound with artesunate was assessed. Acridine, thiazolopyrimidine, quinoxaline, benzimidazole, thiophene, benzodiazepine, isoxazole and pyrimidoindole derivatives showed fast in vitro inhibitory activity of parasite growth, whereas hydrazinobenzimidazole, indenopyridazinone and naphthalenone derivatives were slow-acting in vitro inhibitors. Combinatory profile evaluation indicated that thiazolopyrimidinone and benzodiazepine derivatives have an additive profile, suggesting that the combination of these inhibitors with artesunate is favourable for in vitro inhibitory activity. The remaining compounds showed an antagonistic combinatory profile with artesunate. The collected data indicated that the indenopyridazinone derivative, a bc1 complex inhibitor, had a similar association profile in combination with proguanil when compared to atovaquone combined with proguanil, thereby corroborating the correlation between the molecular target and the combination profile. Lastly, the in vivo activity of the thiazolopyrimidinone and benzodiazepine derivatives were assessed. Both compounds showed oral efficacy at 50 mg/kg in a mouse model of Plasmodium berghei malaria (64% and 40% reduction in parasitaemia on day 5 post-infection, respectively). Conclusions The findings in this paper shed light on the relationship among the speed of action, molecular target and combinatory profile and identified new hits with in vivo activity as candidates for anti-malarial combination therapy.

Triphenyltin acetate toxicity : a biochemical and ultrastructural study on mouse thymocytes

1996 ◽  
Vol 15 (3) ◽  
pp. 219-225 ◽  
Author(s):  
E. Bollo ◽  
L. Ceppa ◽  
E. Cornaglia ◽  
C. Nebbia ◽  
B. Biolatti ◽  
...  
Keyword(s):  
Colorimetric Assay ◽  
Immunosuppressive Agents ◽  
Primary Cultures ◽  
Lactic Dehydrogenase ◽  
Neutral Red ◽  
Transmission Electron ◽  
Dose Dependent ◽  
Triphenyltin Acetate

1 Triphenyltin acetate (TPTA) has been shown to exert in vivo a selective toxic effect on the immune system. To assess in vitro possible alterations induced by TPTA exposure, primary cultures of mouse thymocytes were incubated up to 24 h with graded amounts (1-12 μM) ofthe organotin. 2 The cytotoxic activity has been evaluated with the MTT colorimetric assay, the neutral red (NR) assay and the lactic dehydrogenase (LDH) cellular release. Cell pellets were fixed with 2.5% glutaraldehyde, resin-embedded and ultrathin sections were observed through transmission electron microscopy. 3 After 2 h of incubation, dose-dependent increases of cytotoxicity were observed in thymocytes submitted to MTT and NR tests (up to 41.43% and 18.9%, respectively), while 22 h later this overt effect on cell viability was noticed merely in cells exposed to 12 μM TPTA. Dose- dependent increases of LDH leakage in the culture medium were observed all throughout the study. 4 Morphological investigations revealed features (chro matin condensation, cell membranes fragmentation and formation of membrane bound apoptotic bodies) sugges tive of apoptosis. 5 This study indicates that TPTA is cytotoxic to mouse thymocytes: morphologically, the rising of apoptosis is likely to be recognized, as previously reported in different in vitro studies with other immunosuppressive agents as dioxin and corticosteroids.

RATE OF THYROXINE SECRETION BY MALE AND LAYING JAPANESE QUAIL: IDENTIFICATION OF THE RADIOACTIVE THYROXINE DEGRADATION COMPONENT OF THE MULTIPHASIC 131I CURVE

1975 ◽  
Vol 65 (1) ◽  
pp. 65-71 ◽  
Author(s):  
G. A. ROBINSON ◽  
K. H. TAM
Keyword(s):  
Japanese Quail ◽  
Degradation Rate ◽  
The Body ◽  
Secretion Rate ◽  
Distribution Space ◽  
Rapid Loss ◽  
Serum Samples ◽  
Time Period

SUMMARY Counting of radioactivity in Japanese quail in vivo showed a rapid loss of 131I from the body 12–24 h after the i.v. injection of [131I]thyroxine (T4), followed by a period of slow decrease in counting rates to 96 h. From comparison of these [131I]T4 curves with curves for 131iodide-injected birds and from counts on serum and other tissues in vitro it was concluded that, for Japanese quail, the T4 secretion rate should be calculated using serum samples taken during the first 12 h. Using this time period, the parameters measured were: T4 distribution space, laying hens 45·7 and mature cocks 26·3 ml/100 g body weight; fractional degradation rate for T4, hens 5·73 and cocks 3·12/day; serum T4 concentration (Tetrasorb125 method), hens 1·20 ± 0.07 and cocks 1·34 ± 0.05 (s.e.m.)μg/100 ml (n= 16); T4 secretion rate, hens 3·14 and cocks 1·10 μg/100 g/day.

187 EXPLOITATION OF IN VITRO CAPACITATION FOR NANOPARTICLE INCORPORATION WITHIN MAMMALIAN SPERMATOZOA

2016 ◽  
Vol 28 (2) ◽  
pp. 224
Author(s):  
L. Myles ◽  
C. Durfey ◽  
P. Ryan ◽  
S. Willard ◽  
J. Feugang
Keyword(s):  
Plasma Membrane ◽  
Sperm Motility ◽  
Surface Membrane ◽  
Milk Powder ◽  
Noninvasive Evaluation ◽  
Control Group ◽  
Body Tissues ◽  
Sperm Plasma Membrane

Migration and interactions of mammalian gametes occur in deep body tissues after mating, rendering difficult any in situ noninvasive evaluation of their performances with current methods. In our effort to develop an effective and real-time in vivo imaging approach, we have successfully labelled porcine gametes with self-illuminating bioluminescent and red-shifted quantum dot nanoparticles (QD) in our previous studies (Feugang et al. 2012 J. Nanobiotechnol. 10, 45; Feugang et al. 2015, J. Nanobiotechnol. 13, 38). The present effort aimed at investigating whether QD could be incorporated into spermatozoa through induced in vitro capacitation, which increases sperm plasma membrane fluidity. Fresh extended boar semen was placed on top of a Percoll gradient and centrifuged. Purified motile spermatozoa were collected and washed with pre-warmed PBS. Pelleted spermatozoa were resuspended in the modified Tris-buffered medium with BSA fraction-V (1 mg mL–1; modified Tween medium B with milk powder and BSA). Sperm aliquots (108) were supplemented or not (control) with QD only (QD+; 1 nM), QD+caffeine (2 mM), or QD+heparin (10 µg mL–1); with caffeine and heparin being used as routine capacitant agents in fertilization media. All aliquots were incubated at 38.5°C, under 5% CO2 for 0.5, 1, or 3 h. Spermatozoa were then analysed for motility characteristics and imaged for confirmation of QD-sperm interactions (bioluminescence emission) and localization (transmission electron microscope; TEM). Motility data of 5 replicates were analysed with ANOVA-2, and P < 0.05 was set as threshold of significance. Total sperm motility (TSM) significantly improved with the presence of either or both QDs and capacitant agents after 0.5 and 1 h incubations. With exception of the QD+heparin, all other groups had significantly decreased TSM after 3 h of incubation, when compared with TSM at 0.5 and 1 h. Higher proportions of progressive and rapid (≥45 µm s–1) spermatozoa were observed in the presence of both capacitant agents (P < 0.05), and only QD+heparin maintained greater proportions after 3 h. Sperm straight-line velocity significantly increased in the QD+caffeine at 0.5 h and in both QD+caffeine and QD+heparin thereafter. Sperm straightness data were increased by both caffeine and heparin during incubations. Strong bioluminescence signals were observed in spermatozoa incubated with QDs compared to the background signal seen in the control group. The TEM images revealed consistent surface membrane attachment of QDs in all QD+ groups, whereas transmembrane and intra-spermatic localizations were visible in both QD+caffeine and QD+heparin groups. We concluded that supplementations of medium containing QDs with caffeine or heparin allow the crossing of sperm plasma membrane by QD. No toxic effect of QD on sperm motility was observed, which confirmed our previous report using a similar ratio of QDs over spermatozoa. Exploration of efficient incorporation of QD into spermatozoa as a promising approach for noninvasive molecular imaging is still ongoing, as well as further sperm viability assessments. Supported by the NIH grant #5T35OD010432 and USDA-ARS Biophotonics Initiative grant #58–6402–3-0120.

Hymenolepis diminuta: influence of metacestodes on synthesis and secretion of fat body protein and its ovarian sequestration in the intermediate host, Tenebrio molitor

Parasitology ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Hilary Hurd ◽  
C. Arme
Keyword(s):  
Intermediate Host ◽  
Post Infection ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Body Protein ◽  
Concomitant Reduction ◽  
Fat Bodies

SUMMARYFemale Tenebrio molitor infected with metacestodes of Hymenolepis diminuta exhibit elevated concentrations of female-specific proteins in their haemolymph and the origin of these has been investigated. Following a 4 h in vitro incubation with [14C]leucine, fat bodies from non-infected females secreted 13 times more protein than those from females 12 days post-infection. A comparison of the uptake in vivo of radio-isotope labelled amino acids by ovaries from non-infected and infected beetles of various ages revealed no differences; however, a 51·5% decrease in protein sequestration was detected in females 12 days post-infection. Electrophoresis of homogenates of radio-isotope labelled ovaries demonstrated that the majority of label was associated with vitellin sub-units. It is suggested that the decrease in vitellogenin sequestration associated with infection results in an increase in the haemolymph concentration of these proteins despite a concomitant reduction in their secretion by fat bodies. Both fat body synthesis and ovarian sequestration are under juvenile hormone control and it is proposed that metacestodes of H. diminuta may cause a reduction in the concentration of this hormone in the intermediate host.

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