scholarly journals Mechanisms of pigmentation loss in subterranean fishes

2008 ◽  
Vol 6 (4) ◽  
pp. 657-662 ◽  
Author(s):  
Vanessa Felice ◽  
Maria Aparecida Visconti ◽  
Eleonora Trajano
Keyword(s):  
Complete Loss ◽  
The Other ◽  
In Vitro Tests ◽  
Slight Reduction ◽  
Melanin Synthesis ◽  
Chapada Diamantina ◽  
Proteus Anguinus ◽  
Dark Pigmentation ◽  
Degree Of Regression

Troglobitic (exclusively subterranean) organisms usually present, among their apomorphies related to the subterranean life (troglomorphisms), the regression of eyes and melanic pigmentation. The degree of regression varies among species, from a slight reduction to the complete loss of eyes and dark pigmentation, without a taxonomic correlation. While mechanisms of eye reduction have been intensively investigated in some troglobites such as the Mexican blind tetra characins, genus Astyanax, and the European salamander, Proteus anguinus, few studies have focused on pigmentation. The Brazilian subterranean ichthyofauna distinguishes not only by the species richness (23 troglobitic fishes so far known) but also by the variation in the degree of reduction of eyes and pigmentation. This study focused on Brazilian fishes completely devoid of melanic pigmentation: the characiform Stygichthys typhlops (Characidae) and the siluriforms Ancistrus formoso (Loricariidae), Rhamdiopsis sp.1 (Heptapteridae; from caves in the Chapada Diamantina, Bahia) and Rhamdiopsis sp. 2 (cave in Campo Formoso, Bahia). In order to investigate if such depigmentation is the result of blockage in some step in the melanogenesis, in vitro tests of administration of L-DOPA were done, using caudal-fin fragments extracted from living fish. Except for Rhamdiopsis sp. 2, all the studied species were DOPA(+), i.e., melanin was synthesized after L-DOPA administration. This indicates these fish do have melanophores but they are unable to convert L-tyrosine to L-DOPA. On the other hand, Rhamdiopsis sp. 2, like the albino specimens of Trichomycterus itacarambiensis previously studied (which correspond to one third of the population), are DOPA(-), either because the block of melanin synthesis occurs downstream in melanogenesis, which is probably the case with T. itacarambiensis (monogenic system in view of the phenotypic discontinuity), or because the so-called albinos do no possess melanophores. The physiological loss in the ability to synthesize melanin, apparently caused by different genetic processes in DOPA(+) and in DOPA(-) fishes, may co-exist in subterranean populations with a decrease in the density of melanophores, as observed in the pigmented two thirds of T. itacarambiensis population, a morphological reduction apparently controlled by polygenic systems producing a continuous phenotypic variation.

Design of a Lengthening Element for a Modular Femur Endoprosthetic System

1989 ◽  
Vol 203 (2) ◽  
pp. 97-102 ◽  
Author(s):  
G J Verkerke ◽  
H Schraffordt Koops ◽  
R P H Veth ◽  
J Oldhoff ◽  
H K L Nielsen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Early Stage ◽  
Animal Experiments ◽  
Malignant Tumour ◽  
The Other ◽  
University Hospital ◽  
In Vitro Tests ◽  
Adjacent Tissue ◽  
Non Invasive

A malignant tumour may develop around the knee joint of a child. In the majority of cases it will then be necessary to resect the involved bone with adjacent tissue. A joint team of Groningen University Hospital and University of Twente is currently working on the project of developing a modular endoprosthetic system to bridge the defect resulting from the resection. Since the other, normal, leg continues to grow, the endoprosthetic system will have to include an element the length of which can be adjusted non-invasively. The main conditions to be met by the lengthening element are non-invasive continuous adjustability and a maximum total lengthening of 114 mm. This was achieved by using an external magnetic field. Animal experiments showed that the lengthening element worked well, although moisture infiltrated the telescopic tubes and the lengthening element was covered by proliferating bone at an early stage. Also, the necessary magnetic field proved to be larger than calculated. In a revised design, these problems are resolved. In vitro tests show that the new lengthening element meets all requirements.

Hydrodynamic response of a VAD with a compliant cannula: results of in vitro tests

1994 ◽  
Vol 17 (12) ◽  
pp. 635-642 ◽  
Author(s):  
J.C. Antoranz ◽  
J.F. Del Cañizo ◽  
M.M. Desco
Keyword(s):  
The Other ◽  
Hydrodynamic Performance ◽  
Ventricular Assist Devices ◽  
In Vitro Tests ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Hydrodynamic Response

We report on comparative in vitro tests of two ventricular assist devices (VAD) one with a rigid input cannula and the other with a collapsible (compliant) inlet cannula. We show how this compliant cannula yields significant improvements in the hydrodynamic performance of the system.

THE MODE OF ACTION OF ANTITHYROID DRUGS: RESULTS WITH TWO IN VITRO TESTS

1953 ◽  
Vol 9 (2) ◽  
pp. 224-231 ◽  
Author(s):  
W. R. PITNEY ◽  
T. RUSSELL FRASER
Keyword(s):  
Mode Of Action ◽  
Potassium Thiocyanate ◽  
The Other ◽  
Antithyroid Drugs ◽  
In Vitro Tests ◽  
Maximal Inhibition ◽  
Inhibitory Potency ◽  
Different Types ◽  
Oxidative Iodination

1. Two in vitro tests are described for measuring the inhibitory potency of antithyroid drugs on enzymic and non-enzymic oxidative iodination of protein; one, a milk enzymic iodination test, and the other an enzyme-free peroxide iodination test. 2. Five recognized antithyroid drugs have been tested: 2-thiouracil, 2-carbethoxythio-methyl-glyoxaline, potassium thiocyanate, resorcinol and sulphathiazole. By means of the milk enzymic test they could be ranged in order of potency, as indicated by the molar concentrations required for 50 % inhibition. They could also be separated into different types by the speed with which they pass from minimal to maximal inhibition with rising molar concentration. 3. With the enzyme-free peroxide test, thiouracil, but not resorcinol, was found to be inert; with the enzymic test, both were nearly equivalent in potency.

Insectary tests with insecticides to protect sheep against body strike

1950 ◽  
Vol 1 (4) ◽  
pp. 440 ◽  
Author(s):  
DF Waterhouse ◽  
MT Scott
Keyword(s):  
Solid Material ◽  
The Other ◽  
Lucilia Cuprina ◽  
In Vitro Tests ◽  
Dense Population ◽  
Partial Protection ◽  
Cent Concentration ◽  
Artificial Rain ◽  
High Concentrations

Areas on the backs of sheep were sprayed with several insecticides and a comparison was made of the degree and length of protection thus provided against oviposition, and in one experiment against strike, by Lucilia cuprina when the sheep were exposed to a dense population of flies in an insectary. Indole plugs were tied into the fleece to provide conditions suitable for oviposition. Under these conditions, DDT gave better protection than other insecticides. In 2 per cent. concentration it gave excellent protection for 6-8 weeks; in 1 per cent. concentration the protective period was shorter, although valuable protection was still given. A noticeable feature of the DDT treatments was their long partial protection after some oviposition was permitted, an effect which was not as marked with other insecticides. Crude BHC preparations gave valuable protection when applied at 0.3 per cent. gamma isomer. Intermittent artificial rain, amounting to 17 inches, did not affect the protection afforded by 1.0 per cent. DDT or 0.5 per cent. BHC over a 64-day period. Chlordane gave some protection, but it was less effective than DDT, and chlorinated camphene did not give useful protection. In vitro tests indicated that none of the insecticides was ovicidal. However, in larvicidal tests BHC was extremely toxic, the vapour killing larvae rapidly even when contact with the solid material was prevented. None of the other insecticides had a fumigating action, although in high concentrations they were often lethal on contact.

scholarly journals Effects of Tamoxifen as an Antifungal Agent against Oral Cavity Yeasts in-vitro and in Breast Cancer Patients

2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Ali Abdul Hussein AL-Janabi ◽  
Huda Ali S. Al Mosawe
Keyword(s):  
Breast Cancer ◽  
Oral Cavity ◽  
Cancer Patients ◽  
The Other ◽  
Diffusion Method ◽  
In Vitro Tests ◽  
Breast Cancer Patients ◽  
Oral Flora ◽  
Antifungal Effects

Background: Tamoxifen (TAM) is an effective agent for the treatment of breast cancer and has antifungal activity against various fungi. However, the antifungal effects of TAM in-vivo and in patients under treatment remain unclear. Objectives: The present study aimed to investigate the antifungal effects of TAM on yeast oral flora in-vitro and in breast cancer patients. Methods: In this case-control study, the antifungal effects of TAM were assessed on 50 breast cancer patients receiving TAM treatment, 50 breast cancer patients without TAM treatment, and 50 healthy controls. The disc-diffusion method was used to determine the antifungal effects of TAM on six clinical yeast isolates in-vitro. Results: The number and species count of the yeasts were extremely low in the patients undergoing TAM treatment compared to the other subjects. On the other hand, the absence of the isolates was more evident in the patients receiving TAM treatment (96%). Candida albicans was frequently isolated from all the subjects. In the in-vitro tests, all the yeasts were susceptible to the two concentrations of TAM (5 and 10 µg/mL) at varying degrees. In addition, C. intermedia was the most susceptible yeast species to TAM with a low minimal inhibitory concentration (3.8 µg/mL). Conclusions: According to the results, TAM exerted significant antifungal effects on the yeasts of the oral cavity in the breast cancer patients, showing superior inhibitory effects compared to clotrimazole. Therefore, TAM is recommended as a promising antifungal, while further investigation is required regarding its safety.

scholarly journals Long-Lasting Examinations of Surface and Structural Properties of Medical Polypropylene Modified with Silver Nanoparticles

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2018 ◽  
Author(s):  
Magdalena Ziąbka ◽  
Michał Dziadek
Keyword(s):  
Silver Nanoparticles ◽  
Young Modulus ◽  
Degree Of Crystallinity ◽  
In Vitro Tests ◽  
Slight Reduction ◽  
The Matrix ◽  
Second Year ◽  
The Stability

Composite materials based on polypropylene modified with silver nanoparticles (PP/AgNPs) were manufactured using injection molding and extrusion. Two different matrices were used to prepare the samples consisting of 0.5 and 1.0 wt. % of silver nanoparticles, respectively. The aim of this study was to assess whether silver nanoparticles (AgNPs) could influence the stability of a polymer matrix during the 24-month period of the in vitro testing. The results indicated that composites with silver nanoparticles displayed the significantly higher Young modulus and tensile strength after the first and second year of investigation. Moreover, the incorporation of nanoparticles into the matrix slightly increased the roughness and contact angle values and the parameters remained stable after the in vitro incubation. The two-year immersion of materials in the deionized water proved that the microstructure of composites did not change. The DSC analysis revealed that the material incubation resulted in a slight reduction in the melting temperature and degree of crystallinity of PP. The addition of nanoparticles to polymer matrices led to the increase in content of β crystals in the crystalline phase of PP, which was revealed in the long-term in vitro tests. The XRD measurement also showed the heightened surface crystallinity. The conducted studies have proved that all composites are stable over a period of 24 months. Such behavior suggests that the tested materials can be used as biomaterials.

Bioactivity Responses of Different Uhmwpe Particles from In-Vivo and In-Vitro Tests

2000 ◽  
Vol 662 ◽  
Author(s):  
YoungSoo Park ◽  
ShangYou Yang ◽  
Paul H. Wooley ◽  
Katharine Merritt ◽  
Stephen Hsu ◽  
...  
Keyword(s):  
The Other ◽  
In Vitro Tests ◽  
Textured Surfaces ◽  
Aspect Ratios ◽  
In Vivo Tests ◽  
The Mean ◽  
Particle Size And Shape ◽  
Ultra High Molecular Weight

AbstractThis paper describes the results of bioactivity responses to different ultra high molecular weight polyethylene (UHMWPE) particles. Particles were produced by a wear tester using two different textures of steel counters, one with cross-hatched and the other with uni-hatched grooves. These two textured surfaces produced two distinct populations of wear particles. One is larger and more elongated (fibril shapes) than the other. The mean sizes and aspect ratios of the particles are in the ranges of 5 μm to 25 μm and about 1.5 to 3, respectively. These two distinct UHMWPE particles were examined through in-vitro and in-vivo tests. Macrophages RAW 264.7 and the murine air-pouch model of inflammation were employed to characterize the effect of the particle size and shape. Preliminary in-vivo tests results showed that more elongated and larger particles enhanced bio-reactions.

Anti-Diabetic Activity of a Mineraloid Isolate, in vitro and in Genetically Diabetic Mice

2011 ◽  
Vol 81 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Joel Deneau ◽  
Taufeeq Ahmed ◽  
Roger Blotsky ◽  
Krzysztof Bojanowski
Keyword(s):  
Dna Microarrays ◽  
Human Fibroblasts ◽  
Diabetic Animal ◽  
In Vitro Tests ◽  
Diabetic Mice ◽  
Fossil Material ◽  
Expression Of Genes ◽  
Enhanced Expression ◽  
Genetically Diabetic Mice

Type II diabetes is a metabolic disease mediated through multiple molecular pathways. Here, we report anti-diabetic effect of a standardized isolate from a fossil material - a mineraloid leonardite - in in vitro tests and in genetically diabetic mice. The mineraloid isolate stimulated mitochondrial metabolism in human fibroblasts and this stimulation correlated with enhanced expression of genes coding for mitochondrial proteins such as ATP synthases and ribosomal protein precursors, as measured by DNA microarrays. In the diabetic animal model, consumption of the Totala isolate resulted in decreased weight gain, blood glucose, and glycated hemoglobin. To our best knowledge, this is the first description ever of a fossil material having anti-diabetic activity in pre-clinical models.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

1991 ◽  
Vol 66 (05) ◽  
pp. 609-613 ◽  
Author(s):  
I R MacGregor ◽  
J M Ferguson ◽  
L F McLaughlin ◽  
T Burnouf ◽  
C V Prowse
Keyword(s):  
High Purity ◽  
Time Course ◽  
Prothrombin Complex Concentrate ◽  
Degradation Products ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

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