scholarly journals HEPARIN AS AN ANTIBACTERIAL COATING ON BIODEGRADABLE URETERAL STENTS: EXPERIMENTAL STUDY OF BRAIDSTENT®-H

2021 ◽  
Vol 108 (Supplement_3) ◽  
Author(s):  
J E de la Cruz Conty ◽  
A Budía Alba ◽  
J L Sanz Migueláñez ◽  
J A Galán Llopis ◽  
T Fernández Aparicio ◽  
...  
Keyword(s):  
Dip Coating ◽  
Ureteral Stents ◽  
Biodegradable Stent ◽  
Antibacterial Coating ◽  
Heparin Coating ◽  
Double J Stent ◽  
Effective Inhibition ◽  
Artificial Urine

Abstract INTRODUCTION The aim of this study is to assess the effectiveness of heparin to inhibit the development of early bacteriuria as a coating for biodegradable ureteral stents. MATERIAL AND METHODS The BraidStent®-H biodegradable stent, whose heparin coating is incorporated by dip coating, was chosen for this study. Twenty-four swine were randomly divided into two groups: 12 animals underwent unilateral placement of the BraidStent®-H and 12 were fitted with a standard double-j stent (DJS). Bacteriuria is comparatively analyzed over time by consecutive urine sampling at 0, 1, 3, 6, 12, 24 and 48 hours. In addition, the concentration of heparin released in vitro in artificial urine at 0, 3, 6, 12, 24, 48, 72, 92 and 120 hours is determined via ELISA. RESULTS BraidStent®-H generates a significantly lower bacteriuria rate than a DJS at 6 and 12 hours. Heparin coating shows a significant delaying effect on the onset of bacteriuria, reaching 100% of the animals at 48 hours, compared to the DJS, which takes place at 6 hours. ELISA results reveal the presence of heparin in urine for a total of 72 hours. The coating does not affect the degradation of the device, which is completed at 6 weeks. CONCLUSIONS Heparin evidences an effective inhibition of early bacteriuria, showing its potential as an antibacterial coating for biodegradable ureteral stents. Future studies should focus on the development of long-term heparin coatings for biodegradable materials.

scholarly journals EVALUATION OF THE RELEASE RATE OF A CHEMOTHERAPEUTIC AGENT INCORPORATED AS A COATING ON A BIODEGRADABLE URETERAL STENT. IN VITRO STUDY

2021 ◽  
Vol 108 (Supplement_3) ◽  
Author(s):  
M Soto Gallardo ◽  
J E de la Cruz Conty ◽  
S D Aznar Cervantes ◽  
J L Cenis Anadón ◽  
F M Sánchez Margallo ◽  
...  
Keyword(s):  
Mitomycin C ◽  
Release Rate ◽  
In Vitro Study ◽  
Dip Coating ◽  
Polymeric Matrix ◽  
Ureteral Stent ◽  
Artificial Urine ◽  
Dip Coating Technique ◽  
Mean Concentration

Abstract INTRODUCTION To assess the release rate of Mitomycin C (MMC) after its adherence to a biodegradable ureteral stent (BraidStent™-MMC) by dip coating in order to evaluate its potential application as an adjuvant treatment for upper tract urothelial carcinoma. MATERIAL AND METHODS The dip coating technique is applied to a total of 10 fragments of the BraidStent™ catheter which has a polymeric matrix as a coating. Each 3 cm fragment is immersed 10 times in pure MMC crystallising in methanol and finally obtaining the formation of microlayers on its surface. After drying, each fraction of the stent is immersed in 5 ml of artificial urine to study its interaction with this medium. The samples remain in an orbital shaker at 36ºC and the medium is exchanged under sterile conditions after 12, 24, 48, 48, 72, 96 and 120h. At each replacement, the remaining urine is analysed by HPLC-DAD to quantify the presence of the cytotoxic agent.    RESULTS During the first 12h, MMC is completely released reaching a mean concentration of 52.22 mg/L. Comparing this result with those previously obtained with the first BraidStent ™ -MMC formulation (10.82mg/L), it is determined that this technique allows to increase the release rate up to 5 times. CONCLUSIONS The release rate of Mitomycin C from a biodegradable ureteral stent is increased by integrating a polymeric matrix with microlayers in its coating. Further trials are needed to achieve the therapeutic dose for clinical application in oncology patients.

A new hydrophilic biodegradable ureteral stent restrain encrustation both in vitro and in vivo

2020 ◽  
Vol 35 (6) ◽  
pp. 720-731
Author(s):  
Yu Zhang ◽  
Jian He ◽  
Hechun Chen ◽  
Chengdong Xiong
Keyword(s):  
Lower Amount ◽  
Biodegradable Material ◽  
Ureteral Stents ◽  
Pathological Analysis ◽  
Long Time ◽  
New Type ◽  
Artificial Urine ◽  
Urological Diseases

Ureteral stents have been widely used as biomedical devices to treat some urological diseases for several decades. However, the encrustation complications hamper the long-time clinical use of the ureteral stents. In this work, a new type of biodegradable material for the ureteral stents, methoxypoly(ethylene glycol)-block-poly(L-lactide-ran-Ɛ-caprolactone) (mPEG-PLACL), is evaluated to overcome this problem. The results show that the hydrophilicity and degradation rate in artificial urine of mPEG-PLACL are both significantly increased. It is worth noting that the mPEG-PLACL shows a lower amount of encrustation after immersing the stents in the dynamic urinary extracorporeal circulation (DUEC) model for 7 days. In addition, 71% Ca and 92% Mg are inhibited in vivo by quantitative analysis. Pathological analysis exhibit that the mPEG-PLACL cause less diffuse mucosal hyperplasia after 7 weeks of implantation. All the results indicate that this new type of biodegradable material had an excellent potential for the ureteral stents in the future.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

Human thymic epithelial cells maintain long-term survival of clonogenic myeloid and erythroid progenitor cells in vitro

2000 ◽  
Vol 111 (1) ◽  
pp. 363-370 ◽  
Author(s):  
Katsuto Takenaka ◽  
Mine Harada ◽  
Tomoaki Fujisaki ◽  
Koji Nagafuji ◽  
Shinichi Mizuno ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Progenitor Cells ◽  
Thymic Epithelial Cells ◽  
Erythroid Progenitor ◽  
Term Survival ◽  
Long Term Survival ◽  
Erythroid Progenitor Cells

1450: Double J Stent with Synthetic Heparin Coating does not Prevent Biofilm Deposit and Mineral Incrustation in Comparison with Standard Double J Stent

2007 ◽  
Vol 177 (4S) ◽  
pp. 479-479
Author(s):  
Frédéric Thibault ◽  
Michel Daudon ◽  
Bernard Gattegno ◽  
Olivier Traxer
Keyword(s):  
Heparin Coating ◽  
Double J Stent

Human liver cell cultivation for long-term in vitro toxicity studies in a miniaturized multi-compartment 3D bioreactor system

2011 ◽  
Vol 49 (01) ◽  
Author(s):  
SA Hoffmann ◽  
M Lübberstedt ◽  
U Müller-Vieira ◽  
D Knobeloch ◽  
A Nüssler ◽  
...  
Keyword(s):  
Liver Cell ◽  
Human Liver ◽  
In Vitro Toxicity ◽  
Cell Cultivation ◽  
Toxicity Studies ◽  
Human Liver Cell ◽  
Bioreactor System

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

The depressing (negative) effect of oestradiol benzoate on the in vitro secretion of LH and FSH by the pituitary gland of the LRH-pretreated long-term ovariectomized rat changes into the augmentative (positive) effect after discontinuation of the LRH-pretreatment

1985 ◽  
Vol 110 (3) ◽  
pp. 329-337 ◽  
Author(s):  
G. A. Schuiling ◽  
H. Moes ◽  
T. R. Koiter
Keyword(s):  
Depressing Effect ◽  
Ovx Rats ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate ◽  
Negative Effect ◽  
Positive Effect ◽  
Perifusion System

Abstract. The effect of pretreatment in vivo with oestradiol benzoate on in vitro secretion of LH and FSH was studied in long-term ovariectomized (OVX) rats both at the end of a 5-day continuous in vivo pretreatment with LRH and 4-days after cessation of such LRH pretreatment. Rats were on day 0 sc implanted with osmotic minipumps which released LRH at the rate of 250 ng/h. Control rats were implanted with a piece of silicone elastomer with the dimensions of a minipump. On days 2 and 4 the rats were injected with either 3 μg EB or with oil. On day 5 part of the rats were decapitated and the in vitro autonomous (i.e. non-LRH-stimulated) and 'supra-maximally' LRHstimulated release of LH and FSH was studied using a perifusion system. From other rats the minipumps were removed on day 5 and perifusion was performed on day 9. On the 5th day of the in vivo LRH pretreatment the pituitary LH/FSH stores were partially depleted; the pituitaries of the EB-treated rats more so than those of the oil-injected rats. EB alone had no significant effect on the content of the pituitary LH- and FSH stores. On day 9, i.e. 4 days after removal of the minipumps, the pituitary LH and FSH contents had increased in both the oil- and the EB injected rats, but had not yet recovered to control values. In rats not subjected to the 5-days pretreatment with LRH EB had a positive effect on the supra-maximally LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. EB had no effect on the non-stimulated secretion of FSH. After 5 days of in vivo pretreatment with LRH only, the in vitro non-stimulated and supra-maximally LRH-stimulated secretion of both LH and FSH were strongly impaired, the effect correlating well with the LRH-induced depletion of the pituitary LH/FSH stores. In such LRH-pretreated rats EB had on day 5 a negative effect on the (already depressed) LRH-stimulated secretion of LH (not on that of FSH). EB had no effect on the non-stimulated LH/FSH secretion. It could be demonstrated that the negative effect of the combined LRH/EB pretreatment was mainly due to the depressing effect of this treatment on the pituitary LH and FSH stores: the effect of oestradiol on the pituitary LRH-responsiveness (release as related to pituitary gonadotrophin content) remained positive. In LRH-pretreated rats, however, this positive effect of EB was smaller than in rats not pretreated with LRH. Four days after removal of the minipumps there was again a positive effect of EB on the LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. The positive effect of EB on the pituitary LRH-responsiveness was as strong as in rats which had not been exposed to exogenous LRH. The non-stimulated secretion of FSH was again not affected by EB. The results demonstrate that the effect of EB on the oestrogen-sensitive components of gonadotrophin secretion consists of two components: an effect on the pituitary LRH-responsiveness proper, and an effect on the pituitary LH/FSH stores. The magnitude of the effect of EB on the LRH-responsiveness is LRH dependent: it is very weak (almost zero) in LRH-pretreated rats, but strong in rats not exposed to LRH as well as in rats of which the LRH-pretreatment was stopped 4 days previously. Similarly, the effect of EB on the pituitary LH and FSH stores is LRH-dependent: in the absence of LRH, EB has no influence on the contents of these stores, but EB can potentiate the depleting effect of LRH on the LH/FSH-stores. Also this effect disappear after cessation of the LRH-pretreatment.

THE ROLE OF POLYETHYLENIMINE IN ENHANCING PERFORMANCE OF GLUTAMATE BIOSENSORS

2018 ◽  
Vol 8 (3) ◽  
pp. 36-41
Author(s):  
Diep Do Thi Hong ◽  
Duong Le Phuoc ◽  
Hoai Nguyen Thi ◽  
Serra Pier Andrea ◽  
Rocchitta Gaia
Keyword(s):  
First Generation ◽  
Good Reproducibility ◽  
Complex Matrices ◽  
Long Term Stability ◽  
In Vitro Characterization ◽  
Glutamate Oxidase

Background: The first biosensor was constructed more than fifty years ago. It was composed of the biorecognition element and transducer. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples Glutamate is important biochemicals involved in energetic metabolism and neurotransmission. Therefore, biosensors requires the development a new approach exhibiting high sensibility, good reproducibility and longterm stability. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples. The aims of this work: To find out which concentration of polyethylenimine (PEI) exhibiting the most high sensibility, good reproducibility and long-term stability. Methods: We designed and developed glutamate biosensor using different concentration of PEI ranging from 0% to 5% at Day 1 and Day 8. Results: After Glutamate biosensors in-vitro characterization, several PEI concentrations, ranging from 0.5% to 1% seem to be the best in terms of VMAX, the KM; while PEI content ranging from 0.5% to 1% resulted stable, PEI 1% displayed an excellent stability. Conclusions: In the result, PEI 1% perfomed high sensibility, good stability and blocking interference. Furthermore, we expect to develop and characterize an implantable biosensor capable of detecting glutamate, glucose in vivo. Key words: Glutamate biosensors, PEi (Polyethylenimine) enhances glutamate oxidase, glutamate oxidase biosensors

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