Removal of Dentin by Fuchsin Staining

1976 ◽  
Vol 55 (4) ◽  
pp. 678-683 ◽  
Author(s):  
Yuichiro Sato ◽  
Takao Fusayama
Keyword(s):  
Propylene Glycol ◽  
Solution Method ◽  
Complete Removal ◽  
Basic Fuchsin ◽  
Glycol Solution

When tested in vitro and in vivo, the removal of all dentin stainable by the 0.5% basic fuchsin-propylene glycol solution method assured complete removal of infected carious dentin. The image on the radiograph was always somewhat narrower than the extent of the fuchsin-stainable dentin to be removed.

Preliminary assessment of an injectable extracellular matrix from decellularized bovine myocardial tissue

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hatice Ercan ◽  
Ayşe Eser Elçin ◽  
Yaşar Murat Elçin
Keyword(s):  
Content Analysis ◽  
Complete Removal ◽  
Nuclear Material ◽  
Biological Properties ◽  
Myocardial Tissue ◽  
Rheological Characterization ◽  
Sgag Content ◽  
Tissue Matrix

Abstract The goal of this study was to develop an injectable form of decellularized bovine myocardial tissue matrix which could retain high levels of functional ECM molecules, and could gel at physiological temperature. Dissected ventricular tissue was processed by a detergent-based protocol, lyophilized, enzymatically-digested, and neutralized to form the injectable myocardial matrix (IMM). Histochemical analysis, DNA quantification, and agarose gel electrophoresis demonstrated the efficiency of the applied protocol. Chemical, thermal, morphological, and rheological characterization; protein and sulfated glycosaminoglycan (sGAG) content analysis were performed, in vitro biological properties were evaluated. An in vivo histocompatibility and biodegradability study was performed. Histochemistry revealed complete removal of myocardial cells. DNA content analysis revealed a significant decrease (87%) in the nuclear material, while protein and sGAG contents were highly preserved following decellularization. Soluble IMM was capable of turning into gel form at ∼37 °C, indicating selfassembling property. In vitro findings showed the biomaterial was noncytotoxic, nonhemolytic, and supported the attachment and proliferation of mesenchymal stem cells. In vivo study demonstrated IMM was well-tolerated by rats receiving subcutaneous injection. This work demonstrates that the IMM from decellularized bovine myocardial tissue has the potential for use as a feasible regenerative biomaterial in prospective tissue engineering and regenerative medicine studies.

Ανάπτυξη καινοτόμων νανομορφών για στοχευμένη μεταφορά θεραπευτικών ή/και απεικονιστικών ουσιών στον εγκέφαλο

2021 ◽  
Author(s):  
Μαρία Κανναβού
Keyword(s):  
Propylene Glycol ◽  
Tween 80 ◽  
Capmul Mcm

Η μεταφορά θεραπευτικών και απεικονιστικών ουσιών στον εγκέφαλο, είναι σε αρκετές περιπτώσεις αδύνατη, λόγω της ύπαρξης του αιματοεγκεφαλικού φραγμού (ΑΕΦ). Η εφαρμογή της νανοτεχνολογίας για την αντιμετώπιση αυτού του προβλήματος έχει αρχίσει προσφάτως να δείχνει σημάδια επιτυχίας. Λόγω της δυσκολίας αντιμετώπισης των νευροεκφυλιστικών νόσων και της επιτακτικής ιατρικής ανάγκης που δεν έχει ως σήμερα αντιμετωπιστεί επιτυχώς, γίνεται μεγάλη προσπάθεια προς αυτή την κατεύθυνση.Πρόσφατα έχει αναδειχτεί η εξαιρετική ικανότητα ορισμένων κυστιδίων που παράγονται από τα κύτταρα (εξωκυτταρικά κυστίδια ή εξωσώματα) να μεταφέρουν επιλεκτικά το φορτίο τους σε άλλα κύτταρα που βρίσκονται πολύ μακριά από τα κύτταρα προέλευσης. Ειδικά τα καρκινικά κύτταρα παράγουν εξωσώματα με πολύ καλό οργανοτροπισμό, ο οποίος έχει αναδειχτεί ότι παίζει σημαντικό ρόλο στη μετάσταση.Στόχος αυτής της διατριβής ήταν η διερεύνηση των μηχανισμών μεταφοράς καθώς και των σημαντικών συστατικών που καθορίζουν την οργανοτροπική δράση κυτταρικών κυστιδίων, ώστε να αποτελέσουν τη βάση για τη μελλοντική ανάπτυξη καινοτόμων μορφών λιποσωμάτων με αυξημένη ικανότητα στόχευσης του εγκεφάλου.Στην παρούσα διατριβή έγινε μελέτη της ικανότητας στόχευσης του εγκεφάλου από κυτταρικά κυστίδια (CVs) που προέρχονται από διαφορετικούς τύπους κυττάρων (φυσιολογικά και καρκινικά) και έχουν διαφορετική ιστική προέλευση, ώστε να εντοπιστούν οι βέλτιστες συστάσεις για στόχευση του εγκεφάλου.Αρχικά, δοκιμάστηκε η απομόνωση κυτταρικών κυστιδίων από φυσιολογικά ανθρώπινα επιθηλιακά κύτταρα εγκεφάλου hCMEC/D3 και από καρκινικά κύτταρα μελανώματος ποντικού B16F10. Τα κυστίδια αυτά χαρακτηρίστηκαν ως προς το μέγεθος, το δείκτη πολυδιασποράς και το ζ-δυναμικό, μελετήθηκε ο ρόλος των κυττάρων προέλευσης των CVs στη δυνατότητά τους να διευκολύνουν τη μεταφορά του περιεχομένου τους σε κύτταρα καθώς και η δυνατότητα τροποποίησής τους για βελτίωση της φαρμακοκινητικής τους. Τα κυστίδια αυτά είναι μη τοξικά και έχουν μέγεθος 100-200nm με αρνητικό επιφανειακό φορτίο. Απ' τα αποτελέσματα είναι εμφανής η αυξημένη αλληλεπίδραση των ομόλογων CVs με τα κύτταρα εγκεφάλου (hCMEC/D3) in vitro αλλά και in vivo επιτυγχάνοντας συσσώρευση μεγαλύτερωνποσότητων στον εγκέφαλο ποντικών. Επιπλέον, μελετήθηκε η επίδραση των μέσων καλλιέργειας στη ικανότητα στόχευσης των CVs και αποδείχτηκε ότι το ειδικό θρεπτικό μέσο για τα hCMEC/D3 (EndoGRO) οδηγεί στη δημιουργία CVs με μεγαλύτερη ικανότητα στόχευσης του εγκεφάλου, σε σύγκριση με CVs μεγαλωμένα στο κοινό θρεπτικό μέσο κυττάρων RPMI. Ο εμπλουτισμός των CVs με χοληστερόλη για αύξηση της ακεραιότητας των κυστιδίων, ήταν δυνατός μόνο σε μεμβράνες με χαμηλή περιεκτικότητα χοληστερόλης (hCMEC/D3 CVs). Η προσθήκη PEG και χοληστερόλης στην επιφάνεια των CVs διευκόλυνε τη μεταφορά των ομόλογων CVs στον εγκέφαλο. Στο πλαίσιο της τροποποίησης των κυτταρικών κυστιδίων, μελετήθηκε και η σύντηξη των CVs με PEG-λιποσώματα. Η τεχνική της σύντηξης δοκιμάστηκε με διαφορετικούς τύπους λιποσωμάτων και κυτταρικών κυστιδίων ώστε να επιβεβαιωθεί η λειτουργικότητά της. Τα υβρίδια μεταξύ PEG-λιποσωμάτων και hCMEC CVs, παρόλο που εμφάνισαν μια ελαφρώς βελτιωμένη φαρμακοκινητική σε σχέση με τα αντίστοιχα CVs, δεν κατάφεραν να επαναλάβουν την ίδια στόχευση εγκεφάλου που πραγματοποιήθηκε από τροποποιημένα Chol/PEG CVs. Στη μελέτη του μηχανισμού δράσης των διάφορων τύπων κυστιδίων που χρησιμοποιήθηκαν σε αυτή τη μελέτη, φαίνεται πως τα CVs και τα υβρίδια αλληλεπιδρούν με τα κύτταρα κυρίως μέσω του μονοπατιού της καβεολίνης, σε αντίθεση με τα τροποποιημένα Chol/PEG CVs που χρησιμοποιούν κυρίως το μονοπάτι της κλαθρίνης.Παράλληλα, μελετήθηκε η ικανότητα εγκλωβισμού καινοτόμων νευροπροστατευτικών και νευροαναγεννητικών συνθετικών μικρονευροτροφινών σε λιποσώματα. Τα μόρια αυτά είναι αρκετά λιπόφιλα και διαπερνούν τον ΑΕΦ. Παρόλα αυτά, η χαμηλή υδατοδιαλυτότητά τους και ο τρόπος χορήγησής τους, περιορίζει τη χρήση τους στη θεραπευτική. Αρχικά, με βάση τα πειράματα προμορφοποίησης προσδιορίστηκαν οι βέλτιστες συστάσεις και μέθοδοι παρασκευής των λιποσωμικών μικρονευροτροφινών (ΒΝΝ27 και ΒΝΝ237). Στη συνέχεια, έγιναν προσπάθειες παρασκευής νανομορφών για ενδορρινική χορήγηση του ΒΝΝ27, με σκοπό την άμεση χορήγησή του στον εγκέφαλο και την αντιμετώπιση των μειονεκτημάτων που εμφανίζονται απ’ τη στόχευση του εγκεφάλου μέσω της ενδοφλέβιας οδού χορήγησης. Μελετήθηκε η επικάλυψη των λιποσωμάτων με χιτοζάνη, ένα παράγοντα με βλεννοσυγκολλητικές ιδιότητες, και προσδιορίστηκε η βέλτιστη σύσταση BNN27 λιποσωμάτων PC/PG (9/1) επικαλυμμένα με 0,1 w/w χιτοζάνη/ λιπίδιο, χρησιμοποιώντας τη χιτοζάνη μεσαίου μοριακού βάρους ως πολυμερές βλεννοπροσκόλλησης. Ακόμα, αναπτύχθηκαν νανογαλακτώματα ΒΝΝ27 με βλεννοσυγκολλητικούς παράγοντες (χιτοζάνη ή Carbopol), ως εναλλακτικοί φορείς ενδορρινικής χορήγησης ΒΝΝ27. Μετά τις κατάλληλες μελέτες προμορφοποίησης, προσδιορίστηκαν οι βέλτιστες συστάσεις ΒΝΝ27 νανογαλακτώματος. Τα νανογαλακτώματα με 8% ή 10% w/w Capmul MCM και χιτοζάνη σε ποσοστό 0,3% w/w εμφάνισαν τα βέλτιστα χαρακτηριστικά σταθερότητας και βλεννοπροσκόλλησης. Ως μίγμα επιφανειοδραστικών χρησιμοποιήθηκαν τα έκδοχα Tween 80 / Transcutol / Propylene glycol σε αναλογία 4/1/1. Οι νανομορφές αυτές αφού χαρακτηρίστηκαν ως προς το μέγεθος των σταγονιδίων, το δείκτη πολυδιασποράς, το ζ-δυναμικό και τη μορφολογία τους, μελετήθηκαν ως προς τη σταθερότητα των φυσικοχημικών τους ιδιοτήτων, την κυτταροτοξικότητα, την ικανότητα διαπέρασης ενός in vitro μοντέλου ΑΕΦ και την in vivo συμπεριφορά μετά από ενδορρινική χορήγηση.

scholarly journals Measurement of Novel Dietary Fibers

2004 ◽  
Vol 87 (3) ◽  
pp. 707-717 ◽  
Author(s):  
Barry V McCleary ◽  
Patricia Rossiter
Keyword(s):  
Resistant Starch ◽  
Weight Fraction ◽  
Complete Removal ◽  
High Molecular Weight Fraction ◽  
Interlaboratory Studies ◽  
Human Digestive Tract ◽  
The One ◽  
Good Agreement

Abstract With the recognition that resistant starch (RS) and nondigestible oligosaccharides (NDO) act physiologically as dietary fiber (DF), a need has developed for specific and reliable assay procedures for these components. The ability of AOAC DF methods to accurately measure RS is dependent on the nature of the RS being analyzed. In general, NDO are not measured at all by AOAC DF Methods 985.29 or 991.43, the one exception being the high molecular weight fraction of fructo-oligosaccharides. Values obtained for RS, in general, are not in good agreement with values obtained by in vitro procedures that more closely imitate the in vivo situation in the human digestive tract. Consequently, specific methods for the accurate measurement of RS and NDO have been developed and validated through interlaboratory studies. In this paper, modifications to AOAC fructan Method 999.03 to allow accurate measurement of enzymically produced fructo-oligosaccharides are described. Suggested modifications to AOAC DF methods to ensure complete removal of fructan and RS, and to simplify pH adjustment before amyloglucosidase addition, are also described.

scholarly journals Franz Cell Diffusion Testing and Quantitative Confocal Raman Spectroscopy: In Vitro-In Vivo Correlation

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 887
Author(s):  
Fotis Iliopoulos ◽  
Peter J. Caspers ◽  
Gerwin J. Puppels ◽  
Majella E. Lane
Keyword(s):  
Raman Spectroscopy ◽  
Propylene Glycol ◽  
Human Skin ◽  
Ternary Mixtures ◽  
Drug Bioavailability ◽  
Confocal Raman Spectroscopy ◽  
Topical Formulations ◽  
Confocal Raman

Previously, we reported the use of Confocal Raman Spectroscopy (CRS) to investigate the topical delivery of actives and excipients. We have also correlated the results from CRS with findings from in vitro diffusion studies in human skin. However, until now CRS has only been used as a semi-quantitative method of determining the skin uptake of molecules, with results expressed as arbitrary units of signal intensity. Clearly, this posed challenges for using CRS to determine skin delivery and to assess the drug bioavailability and bioequivalence of topical formulations. In the present work, the permeation of niacinamide (NIA) from various formulations in human skin was studied in vitro using conventional Franz cells and in vivo using a quantitative CRS method under finite dose conditions. The selection of NIA was based on its wide use in pharmaceutical and personal care formulations for many years. This is the first fully quantitative study to compare these methods. The vehicles investigated were neat Transcutol® P (TC); binary combinations of propylene glycol (PG) with propylene glycol monolaurate (PGML); and ternary mixtures of PG, PGML, and isopropyl myristate (IPM). These solvents were selected to encompass a range of physicochemical properties. NIA permeation was evident from all formulations in vitro and in vivo. The vehicles PG:PGML and PG:PGML:IPM delivered comparable amounts across the skin in vitro at 24 h (100.3–106.7 µg/cm2, p > 0.05) that were significantly higher compared with those of TC (1.3 µg/cm2, p < 0.05). An excellent in vitro in vivo correlation (R2 = 0.98) was found following the linear regression of the cumulative amounts of NIA permeated in vitro and the amounts of NIA at 2 μm in the skin measured with CRS. A very good correlation between the cumulative permeation of NIA in vitro and the total amount of NIA that penetrated the stratum corneum (SC) per unit of surface area (μg/cm2) in vivo was also observed, with a Pearson correlation coefficient (R2) of 0.94. The findings support the use of CRS for the quantitative measurement of actives delivered to the skin in vivo. Future studies will focus on exploring the reproducibility and reliability of the method by investigating the delivery of different actives from a wider range of vehicles. Additionally, quantitative CRS will be evaluated further as a method for assessing the bioequivalence of topical formulations.

An experimental in vitro model for evaluating drugs against protoscoleces of Echinococcus granulosus

1990 ◽  
Vol 64 (4) ◽  
pp. 343-348 ◽  
Author(s):  
Rodolfo Lorenzini ◽  
Anna Ruggieri
Keyword(s):  
Propylene Glycol ◽  
Echinococcus Granulosus ◽  
Low Concentrations ◽  
Pharmacological Studies ◽  
Human Sera ◽  
Human Therapy ◽  
Potential Activity ◽  
Vitro Model

ABSTRACTPharmacological studies carried out on protoscoleces in vitro to standardize conditions that would permit a preliminary estimate of the efficacy of drugs with potential activity against Echinococcus granulosus are reported. Media such as PBS and Hanks solution, maintenance temperature, different pH values and concentrations of various solvents have been tested to check the effects on protoscolex survival in tubes in vitro. Mebendazole has been used as the pharmacological standard reference. Changes in the viability of protoscoleces have been used to demonstrate pharmacological activity. Best conditions were obtained employing Hanks solution and propylene glycol at low concentrations. Mebendazole was not completely effective at the concentrations achievable in human therapy. Linear, reproducible results demonstrated that Hanks solution provides an ideal medium for pharmacological studies. Among tested solvents, propylene glycol and dimethyl sulphoxide showed no lethal activity at low concentrations. At concentrations similar to those normally obtained in human sera, mebendazole, as in vivo, demonstrated only partial lethality for protoscoleces. The present study represents a new experimental approach to chemotherapy of hydatid disease.

scholarly journals Studies of the 5′ Exonuclease and Endonuclease Activities of CPSF-73 in Histone Pre-mRNA Processing

2008 ◽  
Vol 29 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Xiao-cui Yang ◽  
Kelly D. Sullivan ◽  
William F. Marzluff ◽  
Zbigniew Dominski
Keyword(s):  
Cleavage Site ◽  
Complete Removal ◽  
Cleavage Product ◽  
Endonucleolytic Cleavage ◽  
Subsequent Degradation ◽  
U7 Snrnp ◽  
Space Requirements ◽  
Polyadenylation Factor

ABSTRACT Processing of histone pre-mRNA requires a single 3′ endonucleolytic cleavage guided by the U7 snRNP that binds downstream of the cleavage site. Following cleavage, the downstream cleavage product (DCP) is rapidly degraded in vitro by a nuclease that also depends on the U7 snRNP. Our previous studies demonstrated that the endonucleolytic cleavage is catalyzed by the cleavage/polyadenylation factor CPSF-73. Here, by using RNA substrates with different nucleotide modifications, we characterize the activity that degrades the DCP. We show that the degradation is blocked by a 2′-O-methyl nucleotide and occurs in the 5′-to-3′ direction. The U7-dependent 5′ exonuclease activity is processive and continues degrading the DCP substrate even after complete removal of the U7-binding site. Thus, U7 snRNP is required only to initiate the degradation. UV cross-linking studies demonstrate that the DCP and its 5′-truncated version specifically interact with CPSF-73, strongly suggesting that in vitro, the same protein is responsible for the endonucleolytic cleavage of histone pre-mRNA and the subsequent degradation of the DCP. By using various RNA substrates, we define important space requirements upstream and downstream of the cleavage site that dictate whether CPSF-73 functions as an endonuclease or a 5′ exonuclease. RNA interference experiments with HeLa cells indicate that degradation of the DCP does not depend on the Xrn2 5′ exonuclease, suggesting that CPSF-73 degrades the DCP both in vitro and in vivo.

scholarly journals THE HISTORY OF DEFERIPRONE (L1) AND THE COMPLETE TREATMENT OF IRON OVERLOAD IN THALASSAEMIA

2020 ◽  
Vol 12 (1) ◽  
pp. e2020011 ◽  
Author(s):  
George J Kontoghiorghes ◽  
Marios Kleanthous ◽  
Christina N. Kontoghiorghe
Keyword(s):  
Complete Removal ◽  
Clinical Use ◽  
Beneficial Effects ◽  
Excess Iron ◽  
Normal Individuals ◽  
Complete Treatment ◽  
History Of ◽  
Families With Children

Deferiprone (L1) was originally designed, synthesised and screened in vitro and in vivo in 1981 by Kontoghiorghes G J following his discovery of the novel alpha-ketohydroxypyridine class of iron chelators (1978-1981), which were intended for clinical use. The journey through the years for the treatment of thalassaemia with L1 has been a very difficult one with intriguing turn of events, which continue until today. Despite many complications, such as the wide use of L1 suboptimal dose protocols, the aim of chelation therapy- namely the complete removal of excess iron in thalassaemia major patients, has been achieved following the introduction of specific L1 and L1/deferoxamine combinations. Many such patients continue to maintain normal iron stores. As a result of the introduction of L1, thalassaemia has changed from a fatal to a chronic disease and thalassaemia patients are active professional members in all sectors of society, have their own families with children and grandchildren and their lifespan is approaching that of normal individuals. No changes in the low toxicity profile of L1 have been observed in more than 30 years of clinical use. Thousands of thalassaemia patients are still denied the cardioprotective and other beneficial effects of L1 therapy. The safety of L1 in thalassaemia and other non-iron loaded diseases resulted in its selection as one of the leading therapeutics for the treatment of Friedreich’s ataxia, pantothenate kinase-associated neurodegeneration and other similar cases. There are also increasing prospects for the application of L1 as a main, alternative or adjuvant therapy in many pathological conditions including cancer, infectious diseases and as a general antioxidant for diseases related to free radical pathology.

scholarly journals P11.40 Development of an implantable multifunctional biodevice (GlioGel) in the treatment of recurrent glioblastoma

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii52-iii52
Author(s):  
L Déry ◽  
G Charest ◽  
M Akbari ◽  
D Fortin
Keyword(s):  
Tumor Cells ◽  
Median Survival ◽  
Complete Removal ◽  
Recurrent Glioblastoma ◽  
Control Group ◽  
Rat Glioma ◽  
F98 Rat Glioma ◽  
Glioma Model

Abstract BACKGROUND Glioblastoma (GBM) is a devastating disease with a median survival of 14–16 months. This poor prognosis can be explained by 3 factors. First, the infiltrative nature of the disease prohibits a complete removal of the tumor. Second, some of the tumor cells are brain tumor stem cells, which are highly migratory and highly resistant to treatments. Finally, the presence of the blood-brain barrier prohibits entry of therapeutics. This situation implies that new treatment approaches must be directed toward the infiltrated brain surrounding the resection cavity. To bypass this problem and improve the potency of adjuvant treatment, we have designed a new “GlioGel-device” that will have the ability to: 1- attract the migrating tumor cells into or nearby the device, and 2- subsequently deliver chemotherapy to the locally pooled tumor cells and 3- irradiate these cells with radioisotopes embedded in the GlioGel. MATERIAL AND METHODS In vitro proof of principle of chemoattraction was investigated by agarose drops method releasing chemokines molecules (CCL2, CCL11, CXCL10) with F98 and U87MG GBM cells. In vivo experiments evaluated the efficiency of chemokines and doxorubicin released by the implanted GlioGel on the tumor behaviour in our Fischer-F98 rat glioma model. An histology of tumour behaviour exposed to chemokines and survival of GBM rats treated with doxorubicin were analysed. RESULTS In vitro preliminary results for chemoattraction assays show that up to 2 times more cells invade the gel when it releases chemoattractant compared to PBS. The In vivo chemotherapy experiments with a fast, medium and slow release of doxorubicin from the GlioGel show that a local dose that represent a 1300-fold smaller dose than a normal intravenous systemic dose gave a significant reduction in tumour growth (median survival) compared to a control group. We investigated the effect provided by the GlioGel impregnated with chemokines on tumor cells migration, after implantation in the Fischer-F98 rat glioma model. CONCLUSION This preliminary study shows the ability of GlioGel releasing chemokines and doxorubicin to respectively attract and kill orthotopic glioblastoma cells. These encouraging results will be completed with a combination of short-range (high LET) radiation by embedded radioisotope into the GlioGel aiming for synergistic combination to eradicate as much tumour cells as possible, while limiting systemic side effects.

Role of follicle wall in meiosis reinitiation induced by insulin in Rana pipiens oocytes

1981 ◽  
Vol 241 (1) ◽  
pp. E51-E56 ◽  
Author(s):  
C. A. Lessman ◽  
A. W. Schuetz
Keyword(s):  
Oocyte Maturation ◽  
Rana Pipiens ◽  
Ovarian Follicle ◽  
Insulin Dose ◽  
Germinal Vesicle ◽  
Complete Removal ◽  
Germinal Vesicle Breakdown ◽  
Maturation In Vitro

The involvement of the ovarian follicle wall in insulin induction of Rana pipiens oocyte maturation in vitro was examined. Complete removal of the follicle wall significantly decreased, but did not obliterate, oocyte maturation (i.e., germinal vesicle breakdown, GVBD) induced by insulin. Dose-response studies of GVBD induction revealed that oocytes within intact follicles were at least 100 times more sensitive to insulin than denuded oocytes. Addition of cyanoketone, a steroid biosynthesis inhibitor, to intact follicles also suppressed insulin-induced GVBD. Inhibitory effects of either follicle wall removal or cyanoketone were not observed when denuded oocytes were treated with progesterone. Addition of either progesterone or pregnenolone to insulin-treated denuded oocytes augmented the oocyte GVBD response compared to either steroid alone and essentially replaced the effect of the follicle wall. In summary, steroidogenesis in the follicle wall appears to be a major factor contributing to the ability of insulin to induce GVBD. However, whether insulin stimulates follicle wall steroidogenesis or simply augments the biological activity of endogenous basal steroid levels is unresolved. The in vitro results show that oocyte maturation can be modulated by the combined actions of several hormones. Such steroid-insulin interactions may also be relevant to understanding the control of oocyte maturation in amphibians and other vertebrates, including mammals, under physiological conditions in vivo.

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