scholarly journals Dependence of the cytostatic effect of adriamycin on drug concentration and exposure time in vitro

1980 ◽  
Vol 41 (6) ◽  
pp. 886-891 ◽  
Author(s):  
H Eichholtz-Wirth
Keyword(s):  
Exposure Time ◽  
Drug Concentration ◽  
Cytostatic Effect

The effects of oxytetracycline on Theileria parva in vitro

Parasitology ◽  
1990 ◽  
Vol 100 (1) ◽  
pp. 11-17 ◽  
Author(s):  
P. R. Spooner
Keyword(s):  
Infected Cell ◽  
Drug Concentration ◽  
Peripheral Blood ◽  
East Coast ◽  
Host Cells ◽  
Theileria Parva ◽  
Cytostatic Effect ◽  
Duration Of Treatment ◽  
Peripheral Blood Leucocytes

SummaryWhen bovine peripheral blood leucocytes were infected with Theileria parva sporozoites, immediate treatment with oxytetracycline (OTC) inhibited the development of sporozoites to mature schizonts. The extent of inhibition was dependent on drug concentration and duration of treatment. Concentrations of 5 μg/ml OTC, or higher, for 8 days completely inhibited the establishment of schizonts and their ability to transform host cells. A cytostatic effect on schizont-infected cell lines was found with three tetracyclines and was also demonstrated on uninfected lymphoblasts. The parasites were found to be sensitive t OTC during development to schizonts, but when mature and established within host cells, schizonts were not demonstrably affected. The infectivity of sporozoites and the binding of sporozoites to lymphocytes were not directly inhibited by OTC. The results may explain the action of tetracyclines when used prophylactically during immunization against East Coast fever, and also the reasons for the ineffectiveness of these drugs when used therapeutically during patent disease.

Methods of experimental polyploidization and their use in apple breeding

2020 ◽  
Vol 62 ◽  
pp. 85-90
Author(s):  
L. V. Tashmatova ◽  
O. V. Matsneva ◽  
T. M. Khromova ◽  
V. V. Shakhov
Keyword(s):  
Exposure Time ◽  
Cell Walls ◽  
Prolonged Exposure ◽  
Ornamental Plants ◽  
Colchicine Treatment ◽  
Apple Trees ◽  
Open Ground ◽  
High Concentrations ◽  
Diploid Gametes

The article presents methods of experimental polyploidy of fruit, berry and ornamental plants. The purpose of this review is to highlight the problems and prospects of polyploidization of plants in the open ground and in vitro culture and the possibility of their application for apple trees. For the purpose of obtaining apple tetraploids as donors of diploid gametes, seed seedlings were treated with a solution of colchicine in concentrations of 0.1-0.4 % for 24 and 48 hours. Colchicine concentrations of 0.3 % and 0.4 % at 48 hours of treatment had a detrimental eff ect on their development. As a result, tetraploids and chimeras were obtained from seeds from free pollination of the varieties Orlik, Svezhest, Kandil Orlovsky, as well as from seeds obtained from crossing the varieties Svezhest×Bolotovskoe, Moskovskoe Оzherel’e×Imrus, Girlyanda×Venyaminovskoe. The optimal concentration of colchicine was 0.1 %. Methods of colchicine treatment have been studied: 1) adding to the nutrient medium, colchicine concentration: 0.01%, 0.02%, exposure time 24h-19 days; 2) applying amitotic solution to the growth point, colchicine concentration: 0.1 %, 0.2 %, exposure time 24h-7 days. To increase the penetration of colchicine through the cell walls, a 0.1 % dimexide solution was used. Studies have shown that high concentrations and prolonged exposure to colchicine reduce the viability of explants.

Comparative activity of anticestode drugs—praziquantel, niclosamide and Compound 77–6, against Hymenolepis nana

1983 ◽  
Vol 57 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Suman Gupta ◽  
J. C. Katiyar
Keyword(s):  
Drug Concentration ◽  
Hymenolepis Nana ◽  
Comparative Activity

AbstractThe activity, in terms of speed of action, of three anticestode drugs against Hymenolepis nana, both in vivo and in vitro, was investigated. Praziquantel was most effective in vivo, but had little action on adult worms and cysticercoids in vitro. Niclosamide, the least effective in vivo, was highly toxic in vitro. Compound 77–6 killed adult worms and cysticercoids in vitro in 10 min and 15 min respectively at 1000 μg/ml of drug concentration, but its in viro effect was intermediate between that of praziquantel and niclosamide.

Evaluation of Paclitaxel Nanocrystals In Vitro and In Vivo

Drug Research ◽  
2017 ◽  
Vol 68 (04) ◽  
pp. 205-212 ◽  
Author(s):  
Wanqing Li ◽  
Zhiguo Li ◽  
Lisha Wei ◽  
Aiping Zheng
Keyword(s):  
Drug Concentration ◽  
Antitumor Effects ◽  
High Drug ◽  
High Drug Concentration ◽  
Low Toxicity ◽  
Nanoparticle Drug Delivery ◽  
Antitumor Evaluation ◽  
Mcf 7

AbstractWe created a novel paclitaxel (PTX) nanoparticle drug delivery system and compared this to acommercial injection preparation to evaluate the antitumor effects for both formulations in vivo and in vitro.PTXnanocrystals were 194.9 nm with potential of −29.6 mV. Cytotoxicity tests indicated that both formulations had similar effects and cytotoxicity was dose- and time-dependent.Pharmacodynamics indicated that the drug concentration at the tumor was greater with PTX nanocrystals compared to commercial injection (P<0.01) and that drug accumulated more and for a longer duration. In vivo antitumor evaluation indicated significant antitumor effects and low toxicity of PTX nanocrystals. Moreover, bioimaging indicated that the PTX retention time in MCF-7-bearing mice was longer, especially at the tumor site, and this high drug concentration was maintained for a long time.Overall, PTX nanocrystalsare feasible and superior to traditional injection formulation chemotherapy.

EXTH-31. BRAIN DISTRIBUTION, CLEARANCE AND TOXICITY EVALUATION OF SMALL-MOLECULE INHIBITORS FOLLOWING CONVECTION-ENHANCED DELIVERY TO THE BRAINSTEM

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi170-vi170
Author(s):  
Erica Power ◽  
Juhee Oh ◽  
Jonghoon Choi ◽  
William Elmquist ◽  
David Daniels
Keyword(s):  
Small Molecule ◽  
Drug Concentration ◽  
Small Molecule Inhibitors ◽  
Efflux Pump ◽  
Sprague Dawley ◽  
Convection Enhanced Delivery ◽  
Efflux Pump Inhibitor ◽  
Delivery Technique ◽  
The Brain

Abstract BACKGROUND Diffuse midline gliomas (DMGs) harboring the H3K27M mutation are highly aggressive, fatal brainstem tumors that primarily occur in children. The blood-brain barrier (BBB) prevents numerous drugs from reaching CNS tumors, like DMG, at cytotoxic concentrations. Convection-enhanced delivery (CED) has emerged as a drug delivery technique that bypasses the BBB through a direct interstitial infusion under a pressure gradient. However, drug distribution and clearance from the brain following CED is poorly understood and has been cited as a potential reason for the lack of efficacy observed in prior clinical trials. OBJECTIVE The objective of this study was to understand how two small molecule inhibitors (alisertib, ponatinib) that inhibit cell growth and proliferation in DMG cells in vitro distribute and clear from the brain following CED to the brainstem. METHODS Sprague-dawley rats underwent a single 60mL CED infusion of drug to the brainstem (200mM alisertib, 10mM ponatinib) and were sacrificed 0.083, 1, 2, 4, 8 and 24 hours following the completion of the infusion. Brains were dissected and drug concentration was determined via HPLC analysis. RESULTS No rats showed any clinical or neurological signs of toxicity post-infusion. Both drugs showed significant differences in drug concentration based on anatomical brain region where higher concentrations were observed in the pons and cerebellum compared to the cortex. Drug half-life in the brain was ~0.5 hours for alisertib and ~1 hour for ponatinib, but this was not significantly increased following co-administration of elacridar, a BBB efflux pump inhibitor. CONCLUSIONS These results suggest that elimination of drugs from the brain in a complex, multifactorial mechanism that warrants further preclinical investigation prior to the initiation of a clinical trial.

scholarly journals 1222. Are Reduced Concentrations of Chlorine-Based Disinfectants Effective Against Candida auris?

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S439-S439
Author(s):  
Jessica Kumar ◽  
Jennifer Cadnum ◽  
Y Karen Ng Wong ◽  
Thriveen Sankar Chittoor Mana ◽  
Heba Alhmidi ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Exposure Time ◽  
Environmental Protection Agency ◽  
Simulated Patient ◽  
Patient Room ◽  
Candida Auris ◽  
Colony Forming Units ◽  
Sodium Dichloroisocyanurate

Abstract Background Currently, sporicidal disinfectants such as bleach are recommended for daily and terminal disinfection of the rooms of patients with Candida auris colonization and/or infection. However, bleach and other chlorine-based disinfectants can have adverse effects on surfaces and personnel. Disinfectant solutions with reduced chlorine concentrations are commonly used for other pathogens, but it is not known if diluted or alternative products maintain efficacy against C. auris both in vitro and in vivo. Methods We tested the efficacy of different concentrations of a sodium dichloroisocyanurate (NaDCC) product and sodium hypochlorite using the method recommended by the Environmental Protection Agency (EPA) for evaluation of the efficacy of liquid disinfectants against C. auris (EPA MLB SOP MB-35-00) and in a simulated patient room. Carriers were exposed to each disinfectant for 1 and 2 minutes. Log reductions were calculated by subtracting viable organisms recovered after disinfectant exposure vs. deionized water controls. Results As shown in the figure, the NaDCC product at 4306 ppm tested with a 2 minute contact time reduced C. auris by ≥5 log10 colony-forming units (CFU) but had reduced efficacy with shorter exposure time or lower concentrations. Sodium hypochlorite was effective with 1 or 2 minute exposure times at a concentration of 6,500 ppm, and was effective at 4,000 ppm with an exposure time of 2 minutes. In the simulated patient room, NaDCC reduced C. auris contamination by ≥6 log10 CFUs on all surfaces. Conclusion A chlorine-based NaDCC product was effective at reducing C. auris. Both NaDCC and sodium hypochlorite products exhibited reduced efficacy at lower concentrations, particularly at concentrations below 4000 ppm. The NaDCC products were also effective in reducing contamination in the simulated patient room. UV-C treatment was an effective adjunct to manual cleaning. Disclosures All authors: No reported disclosures.

scholarly journals Effect of blue laser on viability of Proteus mirabilis

2021 ◽  
pp. 1438-1446
Author(s):  
Mawada M. Funjan
Keyword(s):  
Exposure Time ◽  
Proteus Mirabilis ◽  
Bacterial Species ◽  
Test System ◽  
Blue Laser ◽  
Diffusion Method ◽  
Biochemical Tests ◽  
Burn Wounds ◽  
Antibiotic Susceptibility Test

The usage of blue laser has been considered as a therapeutic approach to prohibit the viability of bacterial species, but there is no agreement about optimum parameters to be used. The aim of this project is to study the influence of blue laser (450 nm) on the viability of the gram-negative bacteria  Proteus mirabilis isolated from burn wounds, using different exposure times (i.e. doses) in vitro. Seventy swab samples were collected from burn wounds of patients admitted to the burns unit in AL-Yarmouk teaching hospital in Baghdad, during the period from June to August 2019. The Bacteria were isolated and identified depending on their culture characteristics, biochemical tests, gram staining, and morphology, being finally confirmed by API 20E Test System. By using the disk diffusion method, susceptibility of the isolates to 12 different antibiotics was examined. One isolate of P. mirabilis was elected according to susceptibility to all antibiotics used.  To prepare bacterial solution, P. mirabilis was mixed with normal saline solution. Dilution of 10-6 cell/ml for p. mirabilis was selected from other serial dilutions. A number of colonies and colony forming units (CFUs/ml) were achieved and correlated to controls.  P. mirabilis was irradiated by blue diode laser (450 nm, 500mw) and exposed to different doses (24, 48, 72, 96, 120J/cm2) corresponding to respective exposure times (4, 8,12,16,20 minutes). The results of antibiotic susceptibility test indicate that the entire isolates of P. mirabilis were multidrug resistant. With the increase in laser dose (exposure times), the number of colonies and  CFUs/ml were reduced, reaching a highest inhibition in CFU/ml  at exposure time of  20 minutes, i.e. a dose of 120J/cm2 , with  irradiance of 0.1 watt/ cm2. No significant reduction was recorded in CFU/ml   at exposure time of 4 min (a dose of 24J/cm2). As a conclusion, the blue laser irradiation at wavelength of 450 nm and 500mw had antibacterial effects on P. mirabilis isolated from burn wounds with irradiance of 0.1watt/cm2 in vitro, as evidenced by the effective reduction in the viability of bacteria at a dose of 120J/cm2 corresponding to exposure time of 20 minutes.

scholarly journals Nebulised Isotonic Hydroxychloroquine Aerosols for Potential Treatment of COVID-19

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1260
Author(s):  
Waiting Tai ◽  
Michael Yee Tak Chow ◽  
Rachel Yoon Kyung Chang ◽  
Patricia Tang ◽  
Igor Gonda ◽  
...  
Keyword(s):  
Drug Concentration ◽  
Systemic Exposure ◽  
Oral Route ◽  
Liquid Volume ◽  
Global Public Health ◽  
Promising Alternative ◽  
High Drug Concentration ◽  
Preclinical And Clinical Studies

The coronavirus disease 2019 (COVID-19) is an unprecedented pandemic that has severely impacted global public health and the economy. Hydroxychloroquine administered orally to COVID-19 patients was ineffective, but its antiviral and anti-inflammatory actions were observed in vitro. The lack of efficacy in vivo could be due to the inefficiency of the oral route in attaining high drug concentration in the lungs. Delivering hydroxychloroquine by inhalation may be a promising alternative for direct targeting with minimal systemic exposure. This paper reports on the characterisation of isotonic, pH-neutral hydroxychloroquine sulphate (HCQS) solutions for nebulisation for COVID-19. They can be prepared, sterilised, and nebulised for testing as an investigational new drug for treating this infection. The 20, 50, and 100 mg/mL HCQS solutions were stable for at least 15 days without refrigeration when stored in darkness. They were atomised from Aerogen Solo Ultra vibrating mesh nebulisers (1 mL of each of the three concentrations and, in addition, 1.5 mL of 100 mg/mL) to form droplets having a median volumetric diameter of 4.3–5.2 µm, with about 50–60% of the aerosol by volume < 5 µm. The aerosol droplet size decreased (from 4.95 to 4.34 µm) with increasing drug concentration (from 20 to 100 mg/mL). As the drug concentration and liquid volume increased, the nebulisation duration increased from 3 to 11 min. The emitted doses ranged from 9.1 to 75.9 mg, depending on the concentration and volume nebulised. The HCQS solutions appear suitable for preclinical and clinical studies for potential COVID-19 treatment.

scholarly journals In vitro Induced Mitotic Polyploidy in Drosera capensis L.

2013 ◽  
Vol 46 (4) ◽  
pp. 107-110 ◽  
Author(s):  
Pavla Zahumenicka ◽  
Barbora Sysova ◽  
Ales Holik ◽  
Eloy C. Fernandez
Keyword(s):  
Flow Cytometry ◽  
Survival Rate ◽  
Exposure Time ◽  
Leaf Segments

Abstract The objective of this study was to induce mitotic polyploidization in Drosera capensis. Tetraploid plants of D. capensis were induced successfully by treating leaf segments in vitro with oryzalin solution with four different concentrations (20, 40, 60 or 80 μM) for 12, 24 or 48 hours. Three tetraploid (2n = 4x = 80) plants were obtained in three treatments (20 μM for 48 h, 60 μM for 24 h and 80 μM for 12 h). Tetraploidy was confirmed by flow cytometry. The survival rate of these plants was not significantly influenced by oryzalin concentration or exposure time.

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