scholarly journals Effect of bacterial endotoxin on the in vitro release of Type II phospholipase-A2 and prostaglandin E2 from human placenta

1999 ◽  
Vol 160 (2) ◽  
pp. 291-296 ◽  
Author(s):  
W Farrugia ◽  
L Nicholls ◽  
GE Rice
Keyword(s):  
Prostaglandin E2 ◽  
Phospholipase A2 ◽  
Incubation Medium ◽  
In Vitro Release ◽  
Bacterial Endotoxin ◽  
Dependent Manner ◽  
Type Ii ◽  
Intracellular Enzyme ◽  
Tissue Content

The aim of this study was to establish the effect of bacterial endotoxin lipopolysaccharide (LPS) on the release of Type II phospholipase-A2 (PLA2) and prostaglandin E2 (PGE2) from late-pregnant human placental tissue incubated in vitro. Under basal conditions, immunoreactive Type II PLA2 and PGE2 were released from tissue explants in a time-dependent manner (up to 24 h, ANOVA, P<0. 0001, n=6). The release of these mediators was not associated with a loss of cell membrane integrity, as indicated by concentrations of the intracellular enzyme, lactate dehydrogenase (LDH), in the incubation medium. Incubation of explants in the presence of LPS (0. 001-100 microg LPS/ml) significantly decreased PLA2 tissue content (P<0.02, n=6) and increased the accumulation of PLA2 and PGE2 in the incubation medium (P<0.0001, n=6). The data obtained in this study indicated that Type II PLA2 and PGE2 are released from term placenta under basal conditions and that LPS stimulated their release. The associated decrease in PLA2 tissue content is consistent with the hypothesis that LPS induces the release of stored PLA2. This study identifies one pathway by which products of bacterial infection may induce the release of a pro-inflammatory, extracellularly active PLA2 from intrauterine tissues that may promote the formation of phospholipid metabolites involved in the process of labour and delivery (e.g. the prostaglandins).

Release of Type II phospholipase A2 immunoreactivity and phospholipase A2 enzymatic activity from human placenta

1997 ◽  
Vol 153 (1) ◽  
pp. 151-157 ◽  
Author(s):  
W Farrugia ◽  
G E Rice ◽  
M H Wong ◽  
K F Scott ◽  
S P Brennecke
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Phospholipase A2 ◽  
Incubation Medium ◽  
Placental Tissue ◽  
Dependent Manner ◽  
Type Ii ◽  
Intracellular Enzyme ◽  
Human Placental Tissue

Abstract The aim of this study was to determine whether Type II phospholipase A2 (PLA2) is released from late pregnant human placental tissue. Placental explants were incubated in vitro and the release of immunoreactive (ir) Type II PLA2 and PLA2 enzymatic activity into the medium was determined. Both irType II PLA2 and PLA2 enzymatic activity accumulated in the incubation medium in a time-dependent manner (P<0·0001). This release was not associated with a loss of cell membrane integrity, as indicated by measurement of the intracellular enzyme, lactate dehydrogenase, in the incubation medium. The concentration of irType II PLA2 and PLA2 enzyme activity present in incubation medium were significantly correlated (P<0·01). Consistent with the hypothesis that Type II PLA2 may be stored in secretory granules within human placental tissue, incubation in the presence of a membrane depolarising concentration of KCl (60 mm) caused the release of irType II PLA2 2·0-fold (P<0·001). PLA2 enzyme activity released into the incubation medium displays biochemical characteristics consistent with those previously reported for secretory PLA2 isozymes, that is, a requirement for millimolar concentrations of calcium for optimal enzyme activity, inhibited by reducing agents, such as dithiothreitol and insensitive to heat inactivation. The data obtained in this study establish that irType II PLA2 is released from term placenta, when incubated in vitro. The release of this extracellularly-active PLA2 isozyme may contribute to gestational and labour-associated increases in glycerophospholipid metabolism and prostaglandin formation. Journal of Endocrinology (1997) 153, 151–157

Formulation and Evaluation of Sustained Release Bilayer Matrix Tablet of Glimepiride and Metformin Hydrochloride

2021 ◽  
pp. 273-279
Author(s):  
Mayuri B. Patil ◽  
Avish D. Maru ◽  
Jayshree S. Bhadane
Keyword(s):  
Sustained Release ◽  
Type Ii Diabetes ◽  
In Vitro Release ◽  
Angle Of Repose ◽  
Metformin Hydrochloride ◽  
Wet Granulation ◽  
Matrix Tablet ◽  
Type Ii ◽  
Weight Variation

The aim of the present study was to design and evaluate bilayer tablets of metformin hydrochloride as sustained release form for the treatment of Type-II diabetes mellitus. The basic aim of any Bi-layer tablet formulation is to separate physically or chemically incompatible ingredients and to produce repeat action or prolonged action of tablet. They are many drugs for treating type-II diabetes. Sulphonyl urea and biguanides are used commonly by a wide section of patients. Melt granulation process was used for the formulation of sustained comprising metformin layer and wet granulation of immediate comprising layer of glimepiride. The precompression studies like bulk density, tapped density, angle of repose, compressible index and post formulation studies includes weight variation, hardness, thickness, friability and dissolution study. The in-vitro release profile of Glimepiride was dissolved within 45 min, and Metformin Hydrochloride was able to release more than 12 hrs. They all the formulation was optimized formula due to its higher rate of dissolution and collate all other parameters with the official specifications.

Antral gland cell column: a method for studying release of gastric hormones

1983 ◽  
Vol 245 (4) ◽  
pp. G463-G469
Author(s):  
B. Richelsen ◽  
J. F. Rehfeld ◽  
L. I. Larsson
Keyword(s):  
In Vitro Release ◽  
Dependent Manner ◽  
Gastrin Release ◽  
Cell Column ◽  
Independent Manner ◽  
Response Characteristics ◽  
Dose Dependent ◽  
Vitro Release ◽  
Stimulation Of

A technique for studying in vitro release of gastric hormones has been developed. The system utilizes nonenzymatically isolated antropyloric glands from humans or rats, which are perifused in a Bio-Gel P-2 column. The system permits the study of kinetics and dose-response characteristics using the glands as their own control. The glands were stimulated with carbachol and bombesin, and the antral peptides gastrin and somatostatin were measured. Bombesin and carbachol both evoked a dose-dependent stimulation of gastrin release, beginning at below 10(-10) M (bombesin) and 10(-7) M (carbachol). Carbachol inhibited the release of somatostatin in a dose-dependent manner, being maximally effective at 10(-6) M and then producing 60% inhibition of somatostatin release. Bombesin was without effect on antropyloric somatostatin release. These data suggest that the gastrin-stimulating effect of carbachol is partially or totally due to inhibition of somatostatin release, whereas bombesinergic stimulation of gastrin release must work in an independent manner. In addition, data on the effects of these substances on the release of gastrin and ACTH-like peptides from human antropyloric glands are presented. Due to the absence of local neural reflexes, this system is a useful supplement to the isolated perfused stomach model.

scholarly journals Effect of the CCL5-Releasing Fibrin Gel for Intervertebral Disc Regeneration

Cartilage ◽  
2018 ◽  
Vol 11 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Zhiyu Zhou ◽  
Stephan Zeiter ◽  
Tanja Schmid ◽  
Daisuke Sakai ◽  
James C. Iatridis ◽  
...  
Keyword(s):  
Animal Study ◽  
Culture Media ◽  
Histopathological Examination ◽  
In Vitro Release ◽  
Dependent Manner ◽  
Fibrin Gel ◽  
Defect Sites ◽  
Intervertebral Disc Regeneration ◽  
Chemotactic Effect

Objective To explore if chemokine (C-C motif) ligand 5 (CCL5) delivery could recruit annulus fibrosus (AF) cells to the injury sites and facilitate the repair of ruptured AF. Design The effects of CCL5 on bovine AF cells in vitro were tested by transwell assay and quantitative real-time polymerase chain reaction. Fibrin gel containing CCL5 was used to treat annulotomized bovine caudal discs cultured under dynamic loading conditions. After 14 days of loading, the samples were collected for histological examination. A pilot animal study was performed using sheep cervical discs to investigate the effect of fibrin gel encapsulated with CCL5 for the treatment of ruptured AF. After 14 weeks, the animals were sacrificed, and the discs were scanned with magnetic resonance imaging before histopathological examination. Results CCL5 showed a chemotactic effect on AF cells in a dose-dependent manner. AF cells cultured with CCL5 in vitro did not show any change of the gene expression of CCL5 receptors, catabolic and proinflammatory markers. In vitro release study showed that CCL5 exhibited sustained release from the fibrin gel into the culture media; however, in the organ culture study CCL5 did not stimulate homing of AF cells toward the defect sites. The pilot animal study did not show any repair effect of CCL5. Conclusions CCL5 has a chemotactic effect on AF cells in vitro, but no ex vivo or in vivo regenerative effect when delivered within fibrin gel. Further study with a stronger chemotactic agent and/or an alternate biomaterial that is more conductive of cell migration is warranted.

Neuropeptide Y Levels in Microdissected Regions of the Hypothalamus and in Vitro Release in Response to KC1 and Prostaglandin E2: Effects of Castration*

Endocrinology ◽  
1987 ◽  
Vol 120 (5) ◽  
pp. 1831-1836 ◽  
Author(s):  
ABHIRAM SAHU ◽  
SATYA P. KALRA ◽  
W. R. CROWLEY ◽  
T. L. O’DONOHUE ◽  
PUSHPA S. KALRA
Keyword(s):  
Prostaglandin E2 ◽  
Neuropeptide Y ◽  
In Vitro Release ◽  
Vitro Release

scholarly journals The transcription factor NRF2 enhances melanoma malignancy by blocking differentiation and inducing COX2 expression

Oncogene ◽  
2020 ◽  
Vol 39 (44) ◽  
pp. 6841-6855 ◽  
Author(s):  
Christina Jessen ◽  
Julia K. C. Kreß ◽  
Apoorva Baluapuri ◽  
Anita Hufnagel ◽  
Werner Schmitz ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Immune Response ◽  
Transcription Factor ◽  
Prostaglandin E2 ◽  
Innate Immune Response ◽  
Stress Responses ◽  
Melanoma Cells ◽  
Innate Immune ◽  
Dependent Manner

AbstractThe transcription factor NRF2 is the major mediator of oxidative stress responses and is closely connected to therapy resistance in tumors harboring activating mutations in the NRF2 pathway. In melanoma, such mutations are rare, and it is unclear to what extent melanomas rely on NRF2. Here we show that NRF2 suppresses the activity of the melanocyte lineage marker MITF in melanoma, thereby reducing the expression of pigmentation markers. Intriguingly, we furthermore identified NRF2 as key regulator of immune-modulating genes, linking oxidative stress with the induction of cyclooxygenase 2 (COX2) in an ATF4-dependent manner. COX2 is critical for the secretion of prostaglandin E2 and was strongly induced by H2O2 or TNFα only in presence of NRF2. Induction of MITF and depletion of COX2 and PGE2 were also observed in NRF2-deleted melanoma cells in vivo. Furthermore, genes corresponding to the innate immune response such as RSAD2 and IFIH1 were strongly elevated in absence of NRF2 and coincided with immune evasion parameters in human melanoma datasets. Even in vitro, NRF2 activation or prostaglandin E2 supplementation blunted the induction of the innate immune response in melanoma cells. Transcriptome analyses from lung adenocarcinomas indicate that the observed link between NRF2 and the innate immune response is not restricted to melanoma.

scholarly journals Stimulation of prostaglandin E2 synthesis by exogenous phospholipase A2 and C in rabbit kidney medulla slices

1984 ◽  
Vol 218 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Y Fujimoto ◽  
N Akamatsu ◽  
A Hattori ◽  
T Fujita
Keyword(s):  
Fatty Acids ◽  
Prostaglandin E2 ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Unsaturated Fatty Acids ◽  
Rabbit Kidney ◽  
Dependent Manner ◽  
Kidney Medulla ◽  
Diacylglycerol Lipase ◽  
Dose Dependent

We have investigated the effects of phospholipase A2 and C on the synthesis of prostaglandin E2 in rabbit kidney medulla and the release of fatty acids from the medulla slices. Exogenous phospholipase A2 [from Naja naja (Indian cobra) venom] and phospholipase C (from Clostridium welchii) stimulated prostaglandin E2 production in a dose-dependent manner. At the maximal effective concentrations (0.5 unit of phospholipase A2/ml, 2 units of phospholipase C/ml), phospholipase C increased prostaglandin E2 formation to the level observed with phospholipase A2. Phospholipase A2 enhanced the release only of unsaturated fatty acids, whereas phospholipase C stimulated the release of individual free fatty acids (C 16:0, C 18:0, C 18:1, C 18:2 and C 20:4). Moreover, p-bromophenacyl bromide inhibited phospholipase A2-stimulated prostaglandin E2 production and the release of fatty acids, but it had no influence on prostaglandin E2 formation and the release of fatty acids increased by phospholipase C, indicating that the stimulatory effect of phospholipase C is not mediated through the activation of endogenous phospholipase A2. These results suggest the presence of diacylglycerol lipase and monoacylglycerol lipase in the kidney and the importance of this pathway in prostaglandin synthesis by the kidney.

scholarly journals Inhibition of leucocytic lysosomal enzymes by glycosaminoglycans in vitro

1975 ◽  
Vol 152 (1) ◽  
pp. 57-64 ◽  
Author(s):  
J L Avila ◽  
J Convit
Keyword(s):  
Incubation Medium ◽  
Lysosomal Enzymes ◽  
Chondroitin Sulphate ◽  
Gradient Centrifugation ◽  
Polymorphonuclear Leucocyte ◽  
Dependent Manner ◽  
Acid Hydrolases ◽  
Lysosomal Fraction ◽  
Formation Of Complexes

1. A lysosomal fraction was separated by density-gradient centrifugation from a highly purified human polymorphonuclear leucocyte suspension. 2. Some 23 different lysosomal enzymes were assayed for activity in the presence of various concentrations of glycosaminoglycans. 3. The 21 acid hydrolases assayed were strongly inhibited to different degrees by low (0-12 mmol/l) concentrations of glycosaminoglycans in a pH-dependent manner. Thus inhibitions were stronger below pH4.5, with activity returning to control values at about pH5.0. 4. On a molar basis, the inhibitory activity for the several glycosaminoglycans studied was: heparin > chondroitin sulphate ≫ hyaluronic acid. 5. Once the glycosaminoglycan-acid hydrolase complex was formed, it was partially dissociated by slight elevations in the pH of the incubation medium, by increasing the ionic strength of the incubation medium, or by adding several cationic proteins (e.g. histone, protamine). 6. As leucocytic lysosomes contain large amounts of chondroitin sulphate, and have a strongly acid intragranular pH, we suggest that glycosaminoglycans may modify lysosomal function through the formation of complexes with lysosomal enzymes, by inhibiting the digestive activity of the acid hydrolases when the intralysosomal pH is below their pI.

A Novel Liposomal Bupivacaine Formulation to Produce Ultralong-Acting Analgesia

2004 ◽  
Vol 101 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Gilbert J. Grant ◽  
Yechezkel Barenholz ◽  
Elijah M. Bolotin ◽  
Mylarrao Bansinath ◽  
Herman Turndorf ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
In Vitro Release ◽  
Rank Test ◽  
Dependent Manner ◽  
Liposomal Bupivacaine ◽  
Freeze And Thaw ◽  
Phospholipid Ratio ◽  
Remote Loading ◽  
Vitro Release

Background Currently available local anesthetics have relatively brief durations of action. An ultralong-acting local anesthetic would benefit patients with acute and chronic pain. The authors prepared and characterized a novel liposomal bupivacaine formulation using remote loading of bupivacaine along an ammonium sulfate gradient and assessed its efficacy in humans. Methods A large multivesicular liposomal bupivacaine formulation was prepared by subjecting small unilamellar vesicles to successive freeze-and-thaw cycles. Bupivacaine hydrochloride was then remotely loaded into the liposomes along an ammonium sulfate gradient ([(NH4)2SO4)]intraliposome/[(NH4)2SO4)]medium &gt; 1000). The liposomes were then characterized for size distribution; drug-to-phospholipid ratio; in vitro release profile at 4 degree, 21 degree C, and 37 degree C; sterility; and pyrogenicity. Six subjects each received six intradermal injections in the lower back with 0.5 ml of 0.5, 1.0, and 2% liposomal bupivacaine; 0.5% standard bupivacaine; saline; and "empty" liposomes. Duration of analgesia was assessed using pinprick testing of the skin directly over the injection sites. Results were compared using the log-rank test. Results The mean large multivesicular vesicle size was 2439 +/- 544 nm, with a drug-to-phospholipid ratio of 1.8, fivefold greater than results previously reported. In vitro release was slowest at 4 degree C. The median duration of analgesia with 0.5% standard bupivacaine was 1 h. The median durations of analgesia after 0.5, 1.0, and 2.0% liposomal bupivacaine were 19, 38, and 48 h, respectively. Neither saline nor "empty" liposomes produced analgesia. Conclusions This novel liposomal formulation had a favorable drug-to-phospholipid ratio and prolonged the duration of bupivacaine analgesia in a dose-dependent manner. If these results in healthy volunteers can be duplicated in the clinical setting, this formulation has the potential to significantly impact the management of pain.

scholarly journals Effect of sodium orthovanadate on ovulation isolated ovarian follicles in Siberian Sturgeon (Acipenser baerii) In Vitro

2021 ◽  
Vol 273 ◽  
pp. 03009
Author(s):  
Dmitry Balashov ◽  
Konstantin Kovalev
Keyword(s):  
Incubation Medium ◽  
Inhibitory Effect ◽  
Ovarian Follicles ◽  
Siberian Sturgeon ◽  
Physiological Status ◽  
Dependent Manner ◽  
Sodium Orthovanadate ◽  
Acipenser Baerii ◽  
Dose Dependent

Effects of sodium orthovanadate on oocyte ovulation were examined during in vitro culture of Siberian sturgeon ovarian follicles from hibernating fish. It was shown that sodium orthovanadate stimulates ovulation of Siberian sturgeon oocytes in a dose-dependent manner. The stimulating or inhibitory effect of vanadate depends on the time of addition to the incubation medium. It was also shown that the stimulating effects of orthovanadate depend on the physiological status of hibernating females whose oocytes were isolated

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