In vitro exhaustion of pancreatic beta-cells

1986 ◽  
Vol 250 (5) ◽  
pp. E502-E511 ◽  
Author(s):  
M. Hoenig ◽  
L. C. MacGregor ◽  
F. M. Matschinsky
Keyword(s):  
Amino Acids ◽  
Arachidonic Acid ◽  
Pancreatic Beta Cells ◽  
Basal Medium ◽  
In Vitro Study ◽  
Bicarbonate Buffer ◽  
Isolated Pancreatic Islets ◽  
Perifusion System ◽  
Secretory Capacity

To learn more about possible limited beta-cell secretory capacity and factors essential for insulin release, a perifusion system was applied that allowed the in vitro study of insulin secretion from isolated pancreatic islets for more than 6 h. Islets isolated from rats were stimulated with various glucose concentrations (7.5, 16.7, and 30 mM), alpha-ketoisocaproate (30 mM), and 30 mM glucose plus 1 mM 3-isobutyl-1-methylxanthine for several hours in Krebs-Ringer-bicarbonate buffer (KRB) or RPMI 1640. Islets showed "exhaustion" with all stimulatory conditions used when KRB was the perifusion medium. This was not prevented by addition of amino acids, phosphate, myo-inositol or arachidonic acid. With RPMI 1640 as the basal medium, exhaustion was not seen at 7.5 mM but was readily approached at higher glucose concentrations. It is possible that the exhaustion phenomenon observed here is due to a depletion of a readily releasable insulin pool.

DECOMPOSITION OF CHLORO-SUBSTITUTED ALIPHATIC ACIDS BY SOIL BACTERIA

1957 ◽  
Vol 3 (2) ◽  
pp. 151-164 ◽  
Author(s):  
H. L. Jensen
Keyword(s):  
Amino Acids ◽  
Yeast Extract ◽  
Soil Bacteria ◽  
Basal Medium ◽  
Soil Extract ◽  
Taxonomic Position ◽  
Vitamin B ◽  
Selective Media ◽  
Aliphatic Acids

Three groups of bacteria capable of decomposing chloro-substituted aliphatic acids were isolated from soil by means of selective media. A group of Pseudomonas-like bacteria (A) decomposed monochloroacetate (and monobromoacetate) readily in media with yeast extract, peptone, or amino acids. They also decomposed α-monochloropropionate with moderate vigor, but had little effect on dichloro-acetate and -propionate, and none on trichloroacetate. A non-sporeforming bacterium of uncertain taxonomic position (B) was able to decompose trichloroacetate in media containing soil extract or vitamin B12, and also in basal medium when associated with vitamin B12-producing strains of Streptomyces. Dichloroacetate was only slightly attacked, and monochloroacetate and α-dichloropropionate not at all. A group of bacteria (C) apparently belonging to Agrobacterium decomposed α-dichloropropionate and dichloroacetate, but was less active towards α-monochloropropionate, and did not attack mono- and tri-chloroacetate. The organisms of groups B and C grew only feebly in ordinary media. The decomposition of monochloroacetate, trichloroacetate, and α-dichloropropionate in soil was accelerated by addition of cell suspensions of groups A, B, and C, respectively. The organisms seemed to be more active in the soil than in vitro.

Activity of dipyrone on intraplatelet arachidonic acid metabolism: An in vitro study

1989 ◽  
Vol 21 (1) ◽  
pp. 43-50 ◽  
Author(s):  
R ABBATE ◽  
S PINTO ◽  
A GORI ◽  
R PANICCIA ◽  
M COPPO ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
In Vitro Study ◽  
Arachidonic Acid Metabolism ◽  
Vitro Study

In vitro study of frog (Rana ridibunda pallas) interrenal function by use of a simplified perifusion system

1981 ◽  
Vol 45 (4) ◽  
pp. 465-472 ◽  
Author(s):  
F. Leboulenger ◽  
A. Belanger ◽  
C. Delarue ◽  
P. Leroux ◽  
P. Netchitailo ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Rana Ridibunda ◽  
Perifusion System

In Vitro Study of the Effect of Osmotic Solutes on the Interactions between Cells from the Peritoneum and Peritoneal Cavity

1994 ◽  
Vol 14 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Andrzej Breborowicz ◽  
Elias Balaskas ◽  
George D. Oreopoulos ◽  
Leo Martis ◽  
Kenneth Serkes ◽  
...  
Keyword(s):  
Amino Acids ◽  
Growth Factors ◽  
Conditioned Medium ◽  
In Vitro Study ◽  
Mesothelial Cells ◽  
Peritoneal Mesothelial Cells ◽  
Inhibition Of Growth ◽  
Peritoneal Leukocytes ◽  
Osmotic Solutes

Objective To study how the presence of osmotic solutes in medium affects growth of the peritoneal mesothelial cells and fibroblasts and how osmotic solutes influence the production of factors regulating growth of these cells. Design The proliferation of mesothelial cells and fibroblasts was evaluated by measuring the incorporation of 3H-thymidine into the cells. Cells were exposed to osmotic solutes; the concentration of the latter in the medium was continuously lowered over the time of the experiment to simulate changes of their concentration in the dialysate. The synthesis of factors influencing the proliferation of the mesothelial cells or fibroblasts, by mesothelial cells or fibroblasts themselves, or by peritoneal leukocytes, was tested by the characteristics of the “conditioned” medium. The conditioned medium was produced by exposing standard medium to mesothelial or fibroblasts monolayer or to peritoneal leukocytes over 24 hours; following filtration it was applied to growing test cells for the study of growth factors. Results The effect of osmotic solutes on the growth of mesothelial cells is less inhibitory when their concentration is gradually lowered over the time of the study, compared to previous findings with a constant concentration. Peritoneal leukocytes produce growth factors for mesothelial cells and fibroblasts. Glucose and amino acids inhibit production of peritonealleukocyte-derived growth factors for mesothelial cells, while glycerol increases synthesis of such growth factors for fibroblasts. Mesothelial cells produce factors stimulating the proliferation of mesothelial cells and fibroblasts. In the presence of glycerol or amino acids synthesis of mesothelium derived growth factors for fibroblasts is augmented. Finally, fibroblasts produce factors that inhibit the proliferation of the mesothelial cells, and this effect is potentiated in the presence of amino acids. Conclusions Cytotoxicity of the osmotic solutes measured by the inhibition of growth of the mesothelial cells or their increased damage is significantly reduced during in vitro kinetic study when the concentration of these solutes is gradually lowered. Presence of osmotic solutes in the medium affects synthesis of growth factors derived from mesothelium, fibroblasts, or peritoneal leukocytes, which affect the proliferation of mesothelial cells or fibroblasts.

scholarly journals The Role of Amino Acids for the In Vitro Culture of Some Species of Forage Legumes I. Trifolium pratense L

2013 ◽  
Vol 70 (1) ◽  
pp. 87-92
Author(s):  
Gabriela Maria VICAȘ ◽  
Mircea SAVATTI
Keyword(s):  
Amino Acids ◽  
In Vitro Culture ◽  
Culture Medium ◽  
Trifolium Pratense ◽  
Basal Medium ◽  
Red Clover ◽  
Forage Legumes ◽  
Trifolium Pratense L

Establishing the effect of the amino acids as additional additives to the culture medium is and will be in the future one of our concerns of interest for the in vitro culture of some plants. The present study examines the effect of the glicocol added to the LS basal medium over the embryos of the Trifolium pratense L specie cultivated in vitro. There were followed: the percentage of plant regeneration of the red clover, its multiplication capacity and the formation of the root system, and also the evolution of the callus obtained on mediums with 2,4D, BA and amino acid.

Sex Difference In Platelet Response To Aspirin Treatment

1981 ◽  
Author(s):  
N S Nicholson ◽  
S L Smith ◽  
R N Saunders
Keyword(s):  
Arachidonic Acid ◽  
Sex Difference ◽  
In Vitro Study ◽  
Female Rats ◽  
Platelet Response ◽  
Male And Female Rats ◽  
Males And Females ◽  
Spontaneous Aggregation

This study was done to determine if a sex difference in response to aspirin similar to that seen in the clinic could be demonstrated in an animal model with hyperactive platelets. The platelet hyperactivity which results in the spontaneous formation of platelet aggregates in retired breeder rats was reduced in both male and female rats by sulfinpyrazone, dipyridamole and indomethacin administered at 20 mg/kg. Aspirin blocked spontaneous aggregation in the male, but had no effect in the female even at doses of 100 mg/kg. Because aspirin is known to be an inhibitor of cyclooxygenase, the metabolism of arachidonic acid was studied in these rats. Arachidonic acid at 20 mg/kg was active in reducing spontaneous aggregation in the male, but had no effect in the female. However, in an in vitro study of the metabolism of arachidonic acid, no significant differences were seen between males and females in the conversion of arachidonic acid to PGF2α, PGE2, TXB2 or HHT. Aspirin was equally effective in both males and females in blocking the in vitro conversion of arachidonic acid via the cyclooxygenase pathway. The retired breeder rat provides a system for meaningful investigations toward understanding the human sex-related differences in platelet sensitivity with aspirin, although the mechanisms of the in vivo male/female platelet sensitivity have not been explained by in vitro studies thus far.

scholarly journals Effects of Current Provisional Restoration Materials on the Viability of Fibroblasts

2009 ◽  
Vol 03 (02) ◽  
pp. 114-119 ◽  
Author(s):  
Mustafa Ulker ◽  
H. Esra Ulker ◽  
Mustafa Zortuk ◽  
Mehmet Bulbul ◽  
Ali Riza Tuncdemir ◽  
...  
Keyword(s):  
Calf Serum ◽  
Basal Medium ◽  
In Vitro Study ◽  
Fibroblast Cell ◽  
Control Group ◽  
Mitochondrial Activity ◽  
Fibroblast Cells ◽  
Cytotoxic Effects ◽  
Provisional Restoration

ABSTRACTObjectives: The aim of the present study was to evaluate the cytotoxic effects of three different provisional restoration materials on fibroblasts. Two bis-acrylic based [Tempofit Duomix (Detax), Protemp 3 Garant (3M ESPE)] and one urethan dimethacrylate [Revotek LC (GC Corporation)] based provisional restoration materials used.Methods: Materials were prepared according to the manufacturers’ instructions in standard teflon disks (2×5mm) and four samples were extracted in 7 ml of Basal Medium Eagle with 10% new born calf serum and 100 mg/ml penicillin/streptomycin for 24 hours. The L929 fibroblast cells were plate (25.000 cells/ml) in well plates, and maintained in a CO2 incubator at 37°C for 24h. After 24 hours, the incubation medium was replaced by the immersed medium in which the samples were stored and the L929 fibroblasts were incubated in contact with eluates for 24 hours at 37°C for 24h. The fibroblast cell viability was analyzed by measuring the mitochondrial activity with the methyltetrazolium test (MTT). Twelve well used for each specimen and experiment repeated for two times. The data was statistically analyzed by Mann-Whitney U tests.Results: The results showed that, Revotek LC and Protemp 3 Garant were not cytotoxic for fibroblast cells when compared to control group (P>.05). However, Tempofit duomix was cytotoxic for L929 fibroblasts when compared to control group and other tested materials (P%.05).Conclusions: Taking into consideration the limitations of an in vitro study, our study indicate that provisional restoration materials might have cytotoxic effects on fibroblasts and should be selected carefully for clinical applications. (Eur J Dent 2009;3:114-119)

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