Effects of concanavalin A on limb regeneration in the axolotl Ambystoma mexicanum

1997 ◽  
Vol 75 (10) ◽  
pp. 1728-1732
Author(s):  
Steven R. Scadding
Keyword(s):  
Pattern Formation ◽  
Concanavalin A ◽  
Limb Regeneration ◽  
Ambystoma Mexicanum ◽  
Teratogenic Effect ◽  
Low Doses ◽  
Con A ◽  
Higher Doses

The purpose of this investigation was to determine the effects, if any, of concanavalin A (Con A) on the process of pattern formation during limb regeneration in the axolotl Ambystoma mexicanum. Con A was administered to regenerating axolotl forelimbs in a Hydron disk that released the Con A slowly over a period of time. The results indicate that Con A is teratogenic to the regenerating axolotl limb, causing reductions in the number, size, and quality of skeletal elements present, with increasing reductions and malformations as the dose is increased. Low doses resulted in a reduction in the number of carpals or phalanges. Higher doses resulted in more drastic malformations, including the absence of digits. The implications of this teratogenic effect of Con A on limb regeneration are discussed in the context of the possible mechanisms of pattern formation.

Citral, an inhibitor of retinoic acid synthesis, modifies pattern formation during limb regeneration in the axolotl Ambystoma mexicanum

1999 ◽  
Vol 77 (11) ◽  
pp. 1835-1837 ◽  
Author(s):  
Steven R Scadding
Keyword(s):  
Retinoic Acid ◽  
Pattern Formation ◽  
Limb Regeneration ◽  
Acid Synthesis ◽  
Ambystoma Mexicanum

While the effects of exogenous retinoids on amphibian limb regeneration have been studied extensively, the role of endogenous retinoids is not clear. Hence, I wished to investigate the role of endogenous retinoic acid during axolotl limb regeneration. Citral is a known inhibitor of retinoic acid synthesis. Thus, I treated regenerating limbs of the larval axolotl Ambystoma mexicanum with citral. The result of this inhibition of retinoic acid synthesis was that limb regeneration became extremely irregular and hypomorphic, with serious pattern defects, or was inhibited altogether. I conclude that endogenous retinoic acid plays an important role in pattern formation during limb regeneration.

Symmetrical vascularization patterns in normal and retinoic acid treated limb regenerates of the axolotl, Ambystoma mexicanum

1998 ◽  
Vol 76 (9) ◽  
pp. 1795-1796 ◽  
Author(s):  
Steven R Scadding ◽  
Andrew Burns
Keyword(s):  
Retinoic Acid ◽  
Pattern Formation ◽  
Vascular System ◽  
Limb Regeneration ◽  
Ambystoma Mexicanum ◽  
Limb Pattern ◽  
Regeneration Blastema

The purpose of this investigation was to determine whether there were any asymmetries in the vascularization of the limb-regeneration blastema in the axolotl, Ambystoma mexicanum, that might be related to pattern formation, and to determine if retinoic acid could modify the vascular patterns of the blastema. We used acrylic casts of the vascular system of the limbs to assess the pattern of vascularization. We observed a very regular symmetrical arrangement of capillaries in the limb-regeneration blastema that did not appear to be modified by doses of retinoic acid sufficient to modify the limb pattern.

scholarly journals DILUCIÓN DE MIEL EN AGUA INDUCE HORMESIS EN LA ACTIVIDAD ANTIBACTERIANA SOBRE Staphylococcus aureus.

2021 ◽  
Vol 19 (suplemento) ◽  
Author(s):  
R Castromán
Keyword(s):  
Antibacterial Activity ◽  
Agar Plate ◽  
Test Organism ◽  
Diffusion Method ◽  
Low Doses ◽  
High Efficacy ◽  
Inhibitory Zone ◽  
The Relationship ◽  
Higher Doses

In pharmacology, hormesis is defined as the high efficacy of a drug at low doses and a decrease of efficacy at higher doses. In this study, the hormesis phenomenon on the antibacterial activity of honey was assessed. The activity of four honeys (A, D, C and D) were checked by agar plate diffusion method using S. aureus (ATCC 29213) as the test organism. Each honey was tested as follows; on the surface of an agar plate, five stainless steel cylinders with a diameter of 8,14 mm were radially disposed. Onto each cylinder 0,1 mL of the sample honey diluted in water at 50 – 25 - 12,5 -6,25 and 3,125 % v/v were placed. Plates were incubated at 35°C during 24 h. The surface of the cylinder diameter was set as reference antibacterial activity (Ra). The antibacterial activity of each honey was quantitated by the relationship between the surface of the inhibitory zone (Iz) and the surface of the reference activity (Iz/Ra). An increase in the antibacterial activity was observed at a concentration of water greater than 50% in honeys B and C. This hormetic behavior could be considered as indicator of the quality of the antibacterial activity of these honeys.  

scholarly journals Genetic control of lymphocyte activation: lack of response to low doses of concanavalin A in lipopolysaccharide-nonresponder mice

1977 ◽  
Vol 146 (4) ◽  
pp. 1146-1151 ◽  
Author(s):  
PH Bick ◽  
U Persson ◽  
E Smith ◽  
E Moller ◽  
L Hammarstrom
Keyword(s):  
B Cell ◽  
Dose Response ◽  
Concanavalin A ◽  
Single Gene ◽  
Lymphocyte Activation ◽  
Inhibitory Effect ◽  
Low Doses ◽  
Spleen Cells ◽  
Con A ◽  
Protein Locus

C3H/HeJ mice do not respond to the polyclonal B-cell activator lipopolysaccharide (LPS) from Escherichia coli; this was first described by Sultzer who observed that mice of this strain did not respond to an intraperitoneal (i.p.) injection of LPS as measured by the accumulation of leukocytes in the peritoneal cavity. Neither were C3H/HeJ mice as susceptible to LPS toxcitiy (1). It was later reported that LPS-induced mitogenesis (2,3), adjuvanticity (4), and the appearance of Ia antigens on B lymphocytes as induced by LPS, (5) was also absent in C3H/HeJ mice. However, lymphocytes from these mice respond normally to the polyclonal B-cell activators purified protein derivative of tuberculin (2,6) and dextran sulfate and have also been reported to respond normally to concanavalin A (Con A) (2). Furthermore, the immune responses to sheep erythrocytes (7) and soluble thymus-dependent antigens (4) are normal in C3H/HeJ mice. Unresponsiveness to LPS in C3H/HeJ mice has been found to Be due to a defect in a single gene or a set of linked genes (3,8) which has been mapped between the major urinary protein locus and the locus coding for polysyndactyly on chromosome 4. (1) We have reported that injection of LPS into mice of an LPS-responsive strain causes a shift in the Con A dose-response curve of cultured spleen cells, suppressing the low does response (9). Therefore, we tested the Con A proliferative response in cultures of normal or LPS-activated spleen cells from LPS-responder (C3H/Tif) and LPS-nonresponder (C3H/HeJ) mice. We report here that C3H/HeJ spleen cells respond poorly to low concentrations of Con A (0.05-0.1 μg/ml). Injection of LPS 2 days before culture inhibits the response to low doses of Con A in cultures of C3H/Tif spleen cells but has no inhibitory effect on the dose response profile of C3H/HeJ spleen cells. Furthermore, the low dose Con A response of spleen cells is dependent upon the presence of an Ia-positive cell. (2) The role of Ia-positive cells in the Con A response of C3H/Tif and C3H/HeJ spleen cells is described.

Involvement of 5-Hydroxytryptamine in Platelet Aggregation In Vivo in Rats and Guinea Pigs

1989 ◽  
Vol 61 (03) ◽  
pp. 463-467 ◽  
Author(s):  
G M Smith
Keyword(s):  
Platelet Count ◽  
Guinea Pigs ◽  
Platelet Adhesion ◽  
Adenosine Diphosphate ◽  
Rate Of Return ◽  
Low Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Rat Platelets

SummaryIn this study, 5-hydroxytryptamine (5-HT) caused a dose- dependent fall in the circulating platelet count suggesting that 5-HT receptors are activated in rat platelets to cause platelet adhesion and aggregation. When low doses of adenosine diphosphate (ADP) were simultaneously injected with 5-HT, there was a significant potentiation of the responses to ADR Ketanserin significantly reduced the potentiated responses. When higher doses of ADP were infused with bolus injections of 5-HT there was no potentiation and ketanserin did not reduce these responses. Ketanserin did not inhibit the collagen-induced fall in circulating platelet count, but did significantly increase the rate of return to the basal platelet count compared with control. 5-HT did not cause a fall in platelet count in guinea-pigs

Concanavalin A-induced Aggregation of Human Blood Platelets

1975 ◽  
Vol 33 (02) ◽  
pp. 354-360 ◽  
Author(s):  
Heinrich Patscheke ◽  
Reinhard Brossmer
Keyword(s):  
Concanavalin A ◽  
Binding Capacity ◽  
Specific Binding ◽  
Blood Platelets ◽  
Residual Effect ◽  
Independent Effect ◽  
Con A ◽  
Experimental Conditions ◽  
Main Effect ◽  
Induced Aggregation

SummaryConcanavalin A (CON A) causes platelets to aggregate. A Ca++-independent effect of CON A could be separated from a main effect which depends on Ca++. The main effect probably is a consequence of the CON A-induced platelet release reaction and therefore is platelet-specific. The weak residual effect observed in the presence of Na2EDTA may be due to a similar mechanism as has been demonstrated for CON A-induced aggregations of several other normal and malignant transformed animal cells.Na2EDTA did not inhibit the carbohydrate-specific binding capacity of CON A. Therefore, Na2EDTA appears not to demineralize the CON A molecules under these experimental conditions.α-methyl-D-glucoside inhibits the Ca++-independent as well as the Ca++-dependent effect of CON A.Pretreatment by neuraminidase stimulated the platelet aggregation induced by CON A. It is possible that removal of terminal sialic acid residues makes additional receptors accessible for the binding of CON A.

scholarly journals Impact of individualized management of breakthrough cancer pain on quality of life in advanced cancer patients: CAVIDIOPAL study

2021 ◽  
Author(s):  
Albert Tuca Rodríguez ◽  
Miguel Núñez Viejo ◽  
Pablo Maradey ◽  
Jaume Canal-Sotelo ◽  
Plácido Guardia Mancilla ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Cancer Pain ◽  
Advanced Cancer ◽  
Low Doses ◽  
Breakthrough Cancer Pain ◽  
Eortc Qlq C30 ◽  
Eortc Qlq ◽  
Individualized Management ◽  
The Impact

Abstract Purpose The main aim of the study was to assess the impact of individualized management of breakthrough cancer pain (BTcP) on quality of life (QoL) of patients with advanced cancer in clinical practice. Methods A prospective, observational, multicenter study was conducted in patients with advanced cancer that were assisted by palliative care units. QoL was assessed with the EORTC QLQ-C30 questionnaire at baseline (V0) and after 28 days (V28) of individualized BTcP therapy. Data on background pain, BTcP, comorbidities, and frailty were also recorded. Results Ninety-three patients completed the study. Intensity, duration, and number of BTcP episodes were reduced (p < 0.001) at V28 with individualized therapy. Transmucosal fentanyl was used in 93.8% of patients, mainly by sublingual route. Fentanyl titration was initiated at low doses (78.3% of patients received doses of 67 μg, 100 μg, or 133 μg) according to physician evaluation. At V28, mean perception of global health status had increased from 31.1 to 53.1 (p < 0.001). All scales of EORTC QLQ-C30 significantly improved (p < 0.001) except physical functioning, diarrhea, and financial difficulties. Pain scale improved from 73.6 ± 22.6 to 35.7 ± 22.3 (p < 0.001). Moreover, 85.9% of patients reported pain improvement. Probability of no ≥ 25% improvement in QoL was significantly higher in patients ≥ 65 years old (OR 1.39; 95% CI 1.001–1.079) and patients hospitalized at baseline (OR 4.126; 95% CI 1.227–13.873). Conclusion Individualized BTcP therapy improved QoL of patients with advanced cancer. Transmucosal fentanyl at low doses was the most used drug. Trial registration This study was registered at ClinicalTrials.gov database (NCT02840500) on July 19, 2016.

scholarly journals Molecular mechanisms of Zika virus teratogenesis from animal studies: a systematic review protocol

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Gabriela Elis Wachholz ◽  
Julia do Amaral Gomes ◽  
Juliano André Boquett ◽  
Fernanda Sales Luiz Vianna ◽  
Lavínia Schuler-Faccini ◽  
...  
Keyword(s):  
Systematic Review ◽  
Animal Models ◽  
Zika Virus ◽  
Methodological Quality ◽  
Molecular Mechanisms ◽  
Grey Literature ◽  
Standard Form ◽  
Teratogenic Effect ◽  
Control Group

Abstract Background Due to the diversity of studies in animal models reporting that molecular mechanisms are involved in the teratogenic effect of the Zika virus (ZIKV), the objective of the present study is to evaluate the methodological quality of these studies, as well as to demonstrate which genes and which molecular pathways are affected by ZIKV in different animal models. Methods This search will be performed in four databases: PubMed/MEDLINE, EMBASE, Web of Science, and Scopus, as well as in the grey literature. The studies selection process will be reported through the PRISMA Statement diagram model. All studies describing the molecular mechanisms possibly involved in the development of malformations caused by embryonic/fetal ZIKV exposure in animal models with an appropriate control group and methodology will be included (including, for instance, randomized and non-randomized studies). All animals used as experimental models for ZIKV teratogenesis may be included as long as exposure to the virus occurred during the embryonic/fetal period. From the selected studies, data will be extracted using a previously prepared standard form. Bias risk evaluation will be conducted following the SYRCLE’s Risk of Bias tool. All data obtained will be tabulated and organized by outcomes (morphological and molecular). Discussion With the proposed systematic review, we expect to present results about the methodological quality of the published studies with animal models that investigated the molecular mechanisms involved in the teratogenic effect of ZIKV, as well as to show the studies with greater reliability. Systematic review registration PROSPERO CRD42019157316

scholarly journals Visualization of intracellular concanavalin A binding sites in retinal photoreceptors.

1978 ◽  
Vol 26 (10) ◽  
pp. 822-828 ◽  
Author(s):  
I Nir
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Photoreceptor Cells ◽  
Con A ◽  
Thin Sections ◽  
Glycol Methacrylate ◽  
Outer Segments ◽  
Retinal Photoreceptors ◽  
Carbohydrate Components ◽  
The Relationship

Localization of carbohydrate components in retinal photoreceptor cells and membranes was studied. Frog and rat retinas were fixed with glutaraldehyde and embedded in glycol methacrylate or in a mixture of glycol methacrylate, glutaraldehyde and urea. Thin sections were incubated with ferritin-labeled concanavalin A (F-Con A) and stained with osmium vapors. Intensive binding was observed in both rod and cone outer segments. In the rod inner segment, differential binding of F-Con A was demonstrated. While numerous ferritin granules were observed in the myoid zone, only a few were seen in the ellipsoid zone, except for a local accumulation along the plasma membrane. In the rod outer segment, Con A binding sites were closely associated with the disk membranes. Ferritin granules were observed on both sides of the membranes. The relationship between the localization of Con A binding sites and the orientation of visual pigment molecules within the rod outer segments disk membranes was discussed.

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