scholarly journals THE EVALUATION OF THERMAL PROPERTIES AND IN VITRO TEST OF CARBODIIMIDE OR GLUTARALDEHYDE CROSS-LINKED GELATIN FOR PC 12 CELLS CULTURE

2005 ◽  
Vol 17 (02) ◽  
pp. 101-107 ◽  
Author(s):  
PEI-RU CHEN ◽  
PEI-LEUN KANG ◽  
WEN-YU SU ◽  
FENG-HUEI LIN ◽  
MING-HONG CHEN
Keyword(s):  
Covalent Binding ◽  
Cell Activity ◽  
Endothermic Peak ◽  
Cross Linking ◽  
Control Group ◽  
In Vitro Test ◽  
Denaturation Temperature ◽  
Vitro Test ◽  
The Stability

The thermal and degradable properties of carbodiimide (EDC) or glutaraldehyde (GTA) cross-linked gelatin membranes have been investigated in order to evaluate the effects of different concentrations of two kinds of cross-linking reagent on the stability of membranes. In the thermogram recorded from a gelatin membrane cross-linked with EDC solution, the endothermic peak of 0.8% EDC cross-linking gelatin was centered at about 61°C that was higher than other samples treated with EDC solutions. Denaturation temperature (Td) of gelatin samples increased on increasing EDC concentration (0.2% to 0.8%), in agreement with the simultaneous increased of the extent of cross-linking. But increasing GTA concentration from 0.05% to 0.6%, the Td values of gelatin samples were decreased from 66.2°C to 56.3°C . In addition, two endothermic peaks were observed in 0.4% and 0.6% GTA cross-linking groups because of the GTA concentration was too high to complete cross-linking reaction. Therefore, partial of gelatin membrane was cross-linked completely but others were not. In the thermogravimetric analysis, the proportion of cracking endothermic peak of 0.6% GTA cross-linking gelatin (g15G0.6) was higher than the peak of 0.6% EDC cross-linking gelatin (g15C0.6). Therefore, g15G0.6 cracked to smaller molecules has to absorb more calorific capacity than g15C0.6. The increase in the strength of covalent binding on increasing the proportion of endothermic peak was evident. The results of degradable rate were in agreement with the lower concentration of cross-linked reagent the faster degraded rate of gelatin membrane. The MTT assay showed that 15% gelatin cross-linked by 0.8% EDC has the least cytotoxicity, and cell activity of this group was similar to control group (blank dish). As the concentration of GTA in gelatin membranes was down to 0.05% or 0.1% the cell viability was returned to approach the value of control group.

IN VITRO DEMONSTRATION OF "HEPARIN REBOUND"

1987 ◽  
Author(s):  
C Taylor ◽  
R F Baugh
Keyword(s):  
Whole Blood ◽  
Cardiovascular Surgery ◽  
Anticoagulant Activity ◽  
Blood Levels ◽  
In Vitro Test ◽  
Neutralizing Activity ◽  
Vitro Test ◽  
The Stability

"Heparin rebound", the in vivo appearance of measurable heparin anticoagulant activity following theapparent neutralization of heparin by protamine, hasbeen a problem sporadically associated with the use of heparin in cardiovascular surgery. A number of mechanisms have been proposed to explain rebound, and to some extent each may contribute to the phenomena. As yet no reliable, predictable method has been demonstrated for measuring, reproducing or quantifying "heparin rebound".We have demonstrated and measured the appearance of heparin anticoagulant activity following neutralization with protamine in citrated whole blood. The reappearance of heparin anticoagulant activity was associated with a rapid loss of protamine. The loss of protamine followed 1st order enzyme kinetics, and was indicative of the action of an enzyme. The anticoagulant activity which eappeared could be titrated againwith protamine. The loss of protamine neutralizing activity, in whole blood, could be followed by titration with heparin using a recalcified activated clotting time. The rate of loss varied with both individual blood donors and with the type and source of protamine. The rate of loss of protamine was great enough to influence in. vivo heparin/protamine neutralization ratios, i.e. at 4 units of heparin/ml, 1 unit/ml anticoagulant activity was routinely recovered within 30 minutes following initial neutralization. The indications for cardiovascular surgery are:1)the in vivo neutralization ratio should be adjusted to account for loss of protamine activity, 2) the higherthe blood levels of heparin used during surgery, themore significant the potential for heparin rebound, and 3) protamines may be evaluated in an in vitro test which measures the stability of protamine neutralizing activity in whole blood.

scholarly journals Cytotoxic and genotoxic effects of the ent-kaurenoic acid and ent-kaurenoic acid enriched Mikania glomerata extract in V79

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Natália Ferreira ◽  
Arthur Ribeiro ◽  
Mariângela Morais ◽  
Aline Peixoto ◽  
Marcela Bernardino ◽  
...  
Keyword(s):  
Test System ◽  
Control Group ◽  
In Vitro Test ◽  
Genotoxic Effects ◽  
V79 Cells ◽  
Kaurenoic Acid ◽  
Biological Potential ◽  
Vitro Test ◽  
Mikania Glomerata

Abstract. Ferreira NH, Ribeiro AB, Morais MD, Peixoto AM, Bernardino MA, Moreira MR, Soares ACF, Heleno VCG, Veneziani RCS, Tavares DC. 2018. Cytotoxic and genotoxic effects of the ent-kaurenoic acid and ent-kaurenoic acid-enriched Mikania glomerata extract in V79. Biofarmasi J Nat Prod Biochem 17: xxxx. The ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel was effective to inhibit the formation of Streptococcus mutans biofilm. In view of the biological potential of this extract and its major component, the present study was carried out to evaluate the safety of the ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel and ent-kaurenoic acid alone in an in vitro test system. The results showed that the ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel was cytotoxic at concentrations up to 40.0 μg/mL. Genotoxic effects were observed in cell cultures treated with the highest concentrations tested of ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel (10.0 and 15.0 µg/mL) and ent-kaurenoic acid alone (2.5, 5.0 and 7.5 µg/mL) when compared to the control group. Therefore, the ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel demonstrated cytotoxicity and genotoxicity effects at the highest concentrations tested, while ent-kaurenoic acid showed to be genotoxic at the same concentrations present in ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel in V79 cells. These results demonstrate that the ent-kaurenoic acid should be responsible, at least in part, of the genotoxicity of ent-kaurenoic acid-rich extract from Mikania glomerata Sprengel.

scholarly journals Selection of probiotic bifidobacteria for lambs

2009 ◽  
Vol 54 (No. 12) ◽  
pp. 552-565 ◽  
Author(s):  
E. Vlková ◽  
M. Grmanová ◽  
V. Rada ◽  
I. Homutová ◽  
S. Dubná
Keyword(s):  
Antimicrobial Activities ◽  
Control Group ◽  
In Vitro Test ◽  
Faecal Samples ◽  
Probiotic Treatment ◽  
Wild Strains ◽  
Vitro Test ◽  
Gradient Plate ◽  
Selection Of

Twenty-six bifidobacteria were isolated from faecal samples of lambs. The isolates were identified, functional properties (survival ability at low pH and bile conditions) and antimicrobial activities against potential pathogens were determined. From the isolates with suitable properties (13 strains) rifampicin-resistant mutants were prepared by gradient plate techniques. This property enabled us to differentiate the administered organism from wild strains because resistance to rifampicin is rare among bifidobacteria. Rifampicin-resistant bifidobacteria (RRBifs) were administered to 3-days-old lambs in two trials. In the first trial the strain <i>B. ruminantium</i> L29 was applied to 3 lambs and was detected in faecal samples at high counts (6 log CFU/g on average) for one week. In the second trial 3 lambs received a “cocktail” of 12 strains and RRBifs survived in the intestinal tract at counts of about 6 log CFU/g for 25 days. The control group without probiotic treatment consisted of 6 animals. In both treated groups RRBifs dominated among bifidobacteria after their administration. Total bifidobacterial counts (5.64–7.32 log CFU/g) were significantly higher (<i>P</i> < 0.05) in treated groups compared to 2.31–2.85 log CFU/g detected in the control group during the first month of lamb life. Lactobacilli counts were also significantly higher (<i>P</i> < 0.05) in treated groups compared to the control. The administered bifidobacteria did not affect any other monitored bacterial groups. On the basis of in vitro test results, suitable probiotic bifidobacterial strains for lambs were chosen. Some of them survived for 30 days in the gastrointestinal tract of treated lambs, but no tested strain was able to colonise the lamb’s tract permanently. The administration of bifidobacterial “cocktail” and consequent identification of the best survived strain seems to be an effective method for selection of potential probiotics.

scholarly journals Study in vitro and in silico on effectiveness noni fruit extract (Morinda Citrifolia) to reducing hypertension

2020 ◽  
pp. 57-64
Author(s):  
La Ode Abdul Haris Hijriansyah ◽  
Hermilasari Hermilasari ◽  
Hardyanty Subair ◽  
Irianto Irianto ◽  
Andi Alief Utama Armyn ◽  
...  
Keyword(s):  
Blood Pressure ◽  
In Silico ◽  
Reduce Blood Pressure ◽  
Morinda Citrifolia ◽  
Control Group ◽  
In Vitro Test ◽  
Fruit Extract ◽  
Average Decrease ◽  
Vitro Test

Hypertension is one of the major causes of stroke. Stroke can be prevented by controlling hypertension. Noni fruit proved to have antihypertensive effect. Noni Fruit contains scopoletin and xeronin compounds that play a role in antihypertensives. This study aims to determine the effectiveness of noni fruit extract to controlling hypertension. The research method used is pre-test and post-test matched control group. The 6 Wistar rats were divided into 3 groups consisting of 1 treatment group and 2 control groups. Group P1 was induced by using ketamine 0.05 ml + epinephrine 0.2 ml + 6 ml noni fruit extract, group K (-) induced by ketamine 0.05 ml + epinephrine 0.2 ml without extract, and group K (+) induced by using ketamine 0.05 ml + epinephrine 0.2 ml + captopril 2.5 mg. The results showed that epinephrine can be used as a hypertensive inducer. Noni fruit extract as much as 6ml can provide antihypertensive effects. In Vitro, test result showed that noni fruit extract can reduce blood pressure by an average decrease in blood pressure of 58,5 mmHg While captopril 25,5 mmHg. in addition to the in vitro test, the results of the in-silico test showed that the noni fruit extract can significantly reduce blood pressure compared to anti-hypertensive drugs (captopril). the value of scopoletin in noni fruit is -7.6. and captopril only -5.7.

Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

1980 ◽  
Vol 44 (01) ◽  
pp. 006-008 ◽  
Author(s):  
D Bergqvist ◽  
K-E Arfors
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
In Vitro Test ◽  
Pharmacological Agents ◽  
Vitro Test ◽  
Releasing Effect ◽  
Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

Reverse torque values of abutment screws after dynamic loading: The effects of sealant agents and the taper of conical connections

2020 ◽  
Author(s):  
Arda Ozdiler ◽  
suleyman dayan ◽  
Burc Gencel ◽  
Gulbahar Isık-Ozkol
Keyword(s):  
Dynamic Loading ◽  
Antibacterial Agent ◽  
In Vitro Study ◽  
Control Group ◽  
Silicone Sealant ◽  
Reverse Torque ◽  
The Stability ◽  
Torque Values ◽  
Chlorhexidine Gel

This in vitro study evaluated the influence of taper angles on the internal conical connections of implant systems and of the application of chlorhexidine gel as an antibacterial agent or a polyvinyl siloxane (PVS) sealant on the reverse torque values of abutment screws after dynamic loading. The current study tested four implant systems with different taper angles (5.4°, 12°, 45°, and 60°). Specimens were divided into three groups: control (neither chlorhexidine gel filled nor silicone sealed), 2% chlorhexidine gel-filled or silicone-sealed group, and group subjected to a dynamic load of 50 N at 1 Hz for 500,000 cycles prior to reverse torque measurements. Quantitative positive correlation was observed between the taper angle degree and the percentage of tightening torque loss. However, this correlation was significant only for the 60° connection groups except in the group in which a sealant was applied ( p = 0.013 for the control group, p = 0.007 for the chlorhexidine group). Percentages of decrease in the torque values of the specimens with silicone sealant application were significantly higher compared with both the control and chlorhexidine groups ( p = 0.001, p = 0.002, p = 0.001, and p = 0.002, respectively, according to the increasing taper angles); the percentage of decrease in torque values due to chlorhexidine application was statistically insignificant when compared with the control group. The application of gel-form chlorhexidine as an antibacterial agent does not significantly affect the stability of the implant–abutment connection under dynamic loads. PVS sealants may cause screw loosening under functional loads.

scholarly journals In Vitro Newly Isolated Environmental Phage Activity against Biofilms Preformed by Pseudomonas aeruginosa from Patients with Cystic Fibrosis

2021 ◽  
Vol 9 (3) ◽  
pp. 478
Author(s):  
Ersilia Vita Fiscarelli ◽  
Martina Rossitto ◽  
Paola Rosati ◽  
Nour Essa ◽  
Valentina Crocetta ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Multidrug Resistant ◽  
In Vitro Test ◽  
Chronic Infections ◽  
Hospital Environments ◽  
Vitro Test ◽  
General Reliability ◽  
Phage Activity

As disease worsens in patients with cystic fibrosis (CF), Pseudomonas aeruginosa (PA) colonizes the lungs, causing pulmonary failure and mortality. Progressively, PA forms typical biofilms, and antibiotic treatments determine multidrug-resistant (MDR) PA strains. To advance new therapies against MDR PA, research has reappraised bacteriophages (phages), viruses naturally infecting bacteria. Because few in vitro studies have tested phages on CF PA biofilms, general reliability remains unclear. This study aimed to test in vitro newly isolated environmental phage activity against PA isolates from patients with CF at Bambino Gesù Children’s Hospital (OBG), Rome, Italy. After testing in vitro phage activities, we combined phages with amikacin, meropenem, and tobramycin against CF PA pre-formed biofilms. We also investigated new emerging morphotypes and bacterial regrowth. We obtained 22 newly isolated phages from various environments, including OBG. In about 94% of 32 CF PA isolates tested, these phages showed in vitro PA lysis. Despite poor efficacy against chronic CF PA, five selected-lytic-phages (Φ4_ZP1, Φ9_ZP2, Φ14_OBG, Φ17_OBG, and Φ19_OBG) showed wide host activity. The Φ4_ZP1-meropenem and Φ14_OBG-tobramycin combinations significantly reduced CF PA biofilms (p < 0.001). To advance potential combined phage-antibiotic therapy, we envisage further in vitro test combinations with newly isolated phages, including those from hospital environments, against CF PA biofilms from early and chronic infections.

In Vitro Toxicology Methods in Risk Assessment

1996 ◽  
Vol 24 (3) ◽  
pp. 325-331
Author(s):  
Iain F. H. Purchase
Keyword(s):  
Risk Assessment ◽  
Hazard Assessment ◽  
Human Health Risk ◽  
In Vitro Test ◽  
In Vitro Methods ◽  
New Concepts ◽  
Vitro Test

The title of this paper is challenging, because the question of how in vitro methods and results contribute to human health risk assessment is rarely considered. The process of risk assessment usually begins with hazard assessment, which provides a description of the inherent toxicological properties of the chemical. The next step is to assess the relevance of this to humans, i.e. the human hazard assessment. Finally, information on exposure is examined, and risk can then be assessed. In vitro methods have a limited, but important, role to play in risk assessment. The results can be used for classification and labelling; these are methods of controlling exposure, analogous to risk assessment, but without considering exposure. The Ames Salmonella test is the only in vitro method which is incorporated into regulations and used widely. Data from this test can, at best, lead to classification of a chemical with regard to genotoxicity, but cannot be used for classification and labelling on their own. Several in vitro test systems which assess the topical irritancy and corrosivity of chemicals have been reasonably well validated, and the results from these tests can be used for classification. The future development of in vitro methods is likely to be slow, as it depends on the development of new concepts and ideas. The in vivo methods which currently have reasonably developed in vitro alternatives will be the easiest to replace. The remaining in vivo methods, which provide toxicological information from repeated chronic dosing, with varied endpoints and by mechanisms which are not understood, will be more difficult to replace.

scholarly journals In vitro dissolution testing models of ocular implants for posterior segment drug delivery

2021 ◽  
Author(s):  
Muhammad Faris Adrianto ◽  
Febri Annuryanti ◽  
Clive G. Wilson ◽  
Ravi Sheshala ◽  
Raghu Raj Singh Thakur
Keyword(s):  
Drug Release ◽  
Posterior Segment ◽  
In Vitro Dissolution ◽  
Prolonged Treatment ◽  
Term Therapy ◽  
In Vitro Test ◽  
Dissolution Testing ◽  
Vitro Test ◽  
Ocular Implants

AbstractThe delivery of drugs to the posterior segment of the eye remains a tremendously difficult task. Prolonged treatment in conventional intravitreal therapy requires injections that are administered frequently due to the rapid clearance of the drug molecules. As an alternative, intraocular implants can offer drug release for long-term therapy. However, one of the several challenges in developing intraocular implants is selecting an appropriate in vitro dissolution testing model. In order to determine the efficacy of ocular implants in drug release, multiple in vitro test models were emerging. While these in vitro models may be used to analyse drug release profiles, the findings may not predict in vivo retinal drug exposure as this is influenced by metabolic and physiological factors. This review considers various types of in vitro test methods used to test drug release of ocular implants. Importantly, it discusses the challenges and factors that must be considered in the development and testing of the implants in an in vitro setup. Graphical abstract

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