scholarly journals Retrograde intrabiliary injection of amphipathic materials causes phospholipid secretion into bile. Taurocholate causes phosphatidylcholine secretion, 3-[(3-cholamidopropyl)dimethylammonio]-propane-1-sulphonate (CHAPS) causes mixed phospholipid secretion

1989 ◽  
Vol 258 (1) ◽  
pp. 17-22 ◽  
Author(s):  
R Coleman ◽  
K Rahman ◽  
K S Kan ◽  
R A Parslow
Keyword(s):  
Bile Acid ◽  
Fold Increase ◽  
Biliary Tree ◽  
Saline Control ◽  
Dose Dependency ◽  
Bile Sample ◽  
Retrograde Intrabiliary Injection ◽  
Single Compound ◽  
Phosphatidylcholine Secretion ◽  
Control Injection

The control of biliary phospholipid and cholesterol secretions by bile acid was studied by using the technique of retrograde intrabiliary injection. Taurocholate (TC), a moderately hydrophobic bile acid, taurodehydrocholate (TDHC), a hydrophilic non-micelle-forming bile acid, and 3-[(3-cholamidopropyl)-dimethylammonio]propane-1-sulphonate (CHAPS), a detergent, were individually administered by retrograde intrabiliary injection (RII) into the biliary tree, and bile acids, phospholipids and cholesterol subsequently appearing in the bile were measured. TC (1.3 mumol; 45 microliters) injected retrogradely provoked a 3.5-fold increase in biliary phospholipid output for 40 min, as compared with the saline control. Injection of 2.7 mumol of TC (90 microliters) caused a 7.5-fold increase in phospholipid output, which reached a peak at 12 min after RII, and phospholipid output continued for 40 min. Cholesterol output was also elicited under these conditions, showing both dose-dependency and extended secretion. Injection of 1.8 mumol of TDHC caused very little increase in either biliary phospholipid or cholesterol. Injection of 0.9 mumol of CHAPS (45 microliters) provoked a single substantial peak of phospholipid output in the 3 min bile sample. T.l.c. analysis of the phospholipid extracts of the bile collected after each compound showed, for TC, a single compound which co-migrated with the phosphatidylcholine standard, whereas for CHAPS substantial amounts of other phospholipids were present.

mechanism of glucagon choleresis in guinea pigs

1990 ◽  
Vol 259 (5) ◽  
pp. G736-G744 ◽  
Author(s):  
R. Lenzen ◽  
V. J. Hruby ◽  
N. Tavoloni
Keyword(s):  
Bile Acid ◽  
Guinea Pigs ◽  
Bile Flow ◽  
Inositol Phosphates ◽  
Biliary Tree ◽  
Glucose Levels ◽  
Prostaglandin Release ◽  
Inhibition Of Prostaglandin Synthesis ◽  
Microtubular System ◽  
Choleretic Effect

The present studies were carried out to clarify the mechanism of glucagon choleresis in guinea pigs. At the infusion rate of 1.4 nmol.min-1.kg-1, glucagon increased bile flow from 206.6 +/- 14.3 to 302.6 +/- 35.0 microliters.min-1.kg-1 and bicarbonate biliary concentration from 63.7 +/- 4.2 to 75.5 +/- 5.9 meq/l. Measurements of bile acid excretion in bile, the biliary tree volume, and of the hormone choleretic effect in guinea pigs with proliferated bile ductules/ducts induced by alpha-naphthylisothiocyanate feeding indicated that glucagon, unlike secretin, stimulated canalicular bile flow. Inhibition of prostaglandin synthesis by indomethacin administration (5 mg.kg-1.h-1) did not modify the choleretic effect of glucagon, and infusion of a glucagon analogue (TH-glucagon, 1.4 nmol.min-1.kg-1), which did not increase hepatic formation of adenosine 3'5'-cyclic monophosphate (cAMP), failed to stimulate bile flow. Like the parent hormone, however, TH-glucagon augmented plasma glucose levels and stimulated formation of inositol phosphates. Colchicine pretreatment (0.5 mg/kg ip) almost entirely prevented the choleretic effect of glucagon but did not modify spontaneous and bile acid-induced bile flow and the stimulatory effect of the hormone on glucose release and on hepatic formation of cAMP and inositol phosphates. Finally, glucagon produced a large increase in the biliary entry of horseradish peroxidase, even though this effect was transient and was not coupled to the increase in bile flow. These results indicate that glucagon choleresis in the guinea pig is not secondary to prostaglandin release, is canalicular in origin, involves bicarbonate secretion, is mediated by cAMP, and requires an intact microtubular system.

Targeting KLF1 for the Treatment of Sickle Cell Disease Using Antisense Oligonucleotides

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4038-4038
Author(s):  
Raechel Peralta ◽  
Audrey Low ◽  
Sheri Booten ◽  
Dewang Zhou ◽  
Aneeza Kim ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mrna Expression ◽  
Sickle Cell ◽  
Antisense Oligonucleotides ◽  
Subcutaneous Administration ◽  
Fetal Hemoglobin ◽  
Fold Increase ◽  
Saline Control ◽  
Globin Mrna ◽  
Globin Reduction

Abstract Sickle cell anemia (SCD) is a hereditary blood disorder in which red blood cells (RBC) become sickle-shaped and block blood vessels, leading to painful vaso-occlusive episodes. Sickling occurs because of a point-mutation in the β-globin gene of hemoglobin. Fetal hemoglobin (HbF, α2γ2) is the main oxygen transport protein in the fetus during the last months of embryonic development and the first few months of life after birth. HbF has a slightly greater oxygen binding affinity than adult hemoglobin (HbA, α2β2) and inhibits sickling by interfering with the polymerization of hemoglobin S. Higher HbF levels in SCD correlate with better survival and because HbF production can be reactivated pharmacologically in adults, it can be used for the treatment of SCD. Erythroid Kruppel-like factor (KLF1) is an erythroid-specific transcription factor that regulates β-globin expression through direct interaction with its promoter and indirectly regulates γ-globin expression through the regulation of BCL11A. By reducing the expression of KLF1, we can promote production of HbF through the upregulation of γ-globin expression. Since rodents don’t express γ-globin, we have employed both human and engineered mouse cell lines to demonstrate upregulation of γ-globin mRNA expression in vitro. We used MEL-h-b-BAC line#7 cells, a murine erythroleukemic cell line harboring the entire human beta globin locus and expressing mouse KLF1, and treated with antisense oligonucleotides (ASOs) targeting mouse KLF1. After 7 days of free uptake with the ASOs, we observed a 6-fold increase of human γ-globin mRNA expression after achieving 65% mRNA reduction of mouse KLF1 compared to the untreated control. We were also able to demonstrate significant upregulation of human γ-globin protein expression in these cells by western blot. We have shown similar results in a human erythroleukemia cell line, K562, using ASOs targeting human KLF1. K562 cells were electroporated with the KLF1 ASOs and 4 days later, we observed a 5-fold increase of human γ-globin mRNA expression after achieving 40% mRNA reduction of human KLF1 compared to the untreated control. These data indicate that targeting mouse or human KLF1 with ASO treatment can cause an increase in human γ-globin expression in vitrothat is necessary for the upregulation of fetal hemoglobin. We have also shown that we are able to target the bone marrow in both mice and rats through subcutaneous administration of our KLF1 ASOs. In wild type mice, at a dose of 100 mpk/wk for 4 weeks, we observed KLF1 target reduction of 88% and a β-globin reduction of 58% compared to the saline control in whole bone marrow. In Sprague-Dawley rats, at a dose of 50 mpk/wk for 4 weeks, we observed KLF1 target reduction of 83% and a β-globin reduction of 77% compared to the saline control in whole bone marrow. Therefore, we are able to achieve significant β-globin mRNA reduction in the bone marrow in both mice and rats after subcutaneous administration of KLF ASOs. These data indicate that reducing KLF1 with antisense oligonucleotides is a viable option for the treatment of sickle cell anemia. Disclosures Peralta: Isis Pharmaceuticals, Inc.: Employment. Low:Isis Pharmaceuticals, Inc.: Employment. Booten:Isis Pharmaceuticals, Inc.: Employment. Zhou:Univeristy of Alabama at Birmingham: Employment. Kim:Isis Pharmaceuticals, Inc.: Employment. Freier:Isis Pharmaceuticals, Inc.: Employment. Guo:Isis Pharmaceuticals, Inc.: Employment. Murray:Isis Pharmaceuticals, Inc.: Employment. Townes:University of Alabama at Birmingham: Employment. Hung:Isis Pharmaceuticals, Inc.: Employment.

scholarly journals Increased cholesterol 7α-hydroxylase expression and size of the bile acid pool in the lactating rat

2008 ◽  
Vol 294 (4) ◽  
pp. G1009-G1016 ◽  
Author(s):  
Clavia Ruth Wooton-Kee ◽  
David E. Cohen ◽  
Mary Vore
Keyword(s):  
Bile Acid ◽  
Protein Expression ◽  
Mrna Expression ◽  
Bile Acids ◽  
Fold Increase ◽  
Bile Acid Pool ◽  
Hydrophobicity Index ◽  
Acid Pool ◽  
Bile Acid Transporters ◽  
Cholic Acids

Maximal bile acid secretory rates and expression of bile acid transporters in liver and ileum are increased in lactation, possibly to facilitate increased enterohepatic recirculation of bile acids. We determined changes in the size and composition of the bile acid pool and key enzymes of the bile acid synthetic pathway [cholesterol 7α-hydroxylase (Cyp7a1), sterol 27-hydroxylase (Cyp27a1), and sterol 12α-hydroxylase (Cyp8b1)] in lactating rats relative to female virgin controls. The bile acid pool increased 1.9 to 2.5-fold [postpartum (PP) days 10, 14, and 19–23], compared with controls. A 1.5-fold increase in cholic acids and a 14 to 20% decrease in muricholic acids in lactation significantly increased the hydrophobicity index. In contrast, the hepatic concentration of bile acids and small heterodimer partner mRNA were unchanged in lactation. A 2.8-fold increase in Cyp7a1 mRNA expression at 16 h (10 h of light) demonstrated a shift in the diurnal rhythm at day 10 PP; Cyp7a1 protein expression and cholesterol 7α-hydroxylase activity were significantly increased at this time and remained elevated at day 14 PP but decreased to control levels by day 21 PP. There was an overall decrease in Cyp27a1 mRNA expression and a 20% decrease in Cyp27a1 protein expression, but there was no change in Cyp8b1 mRNA or protein expression at day 10 PP. The increase in Cyp7a1 expression PP provides a mechanism for the increase in the bile acid pool.

Triiodothyronine influences digesta kinetics and methane yield in sheep

2012 ◽  
Vol 52 (7) ◽  
pp. 572 ◽  
Author(s):  
M. C. Barnett ◽  
J. P. Goopy ◽  
J. R. McFarlane ◽  
I. R. Godwin ◽  
J. V. Nolan ◽  
...  
Keyword(s):  
Retention Time ◽  
Volatile Fatty Acid ◽  
Methane Yield ◽  
Saline Control ◽  
Microbial Protein ◽  
Faecal Excretion ◽  
Enteric Methane ◽  
Protein Output ◽  
Daily Changes ◽  
Control Injection

Methane yield from ruminants is positively correlated with mean retention time (MRT) of digesta, which is known to be influenced by the hormone triiodothyronine (T3).We hypothesised that a decrease in the MRT in the rumen in response to administration of a T3 solution to sheep would reduce their methane yield. To test this hypothesis, 10 mature Merino wethers were injected with T3 (300 µg) on two different protocols (daily; n = 5 and every second day; n = 5) and the effect on daily methane yield, digesta MRT, DM digestibility, rumen volatile fatty acid concentrations, microbial protein output and plasma T3 concentrations studied. Compared with when injected with saline (control), injection of sheep with T3 every second day resulted in decreased methane yield (P < 0.05) and lower acetate (P < 0.001), butyrate (P < 0.001) and propionate (P < 0.01) concentrations in the rumen. MRT of digesta, derived from faecal excretion of CoEDTA and Cr-mordanted fibre, were reduced in the total tract (P < 0.001) and hindgut (P < 0.01) but not in the rumen (P > 0.05). DM digestibility was not affected by injection of T3 every second day but water intake (P < 0.05) and urine output (P < 0.01) were increased. When sheep were injected with T3 daily, changes were only observed in plasma T3 concentration (P < 0.001) and volume of CO2 produced (P < 0.05). The results indicate that increasing plasma concentration of the thyroid hormone T3 within physiological levels reduces digesta retention time, especially retention time in the hindgut and leads to a reduction in enteric methane yield. Further work is warranted to assess whether plasma T3 concentrations may be indicative of enteric methane yield.

Penicillium piceum: a potential source for antimicrobial agents and β-lactamase inhibitors

Biologia ◽  
2015 ◽  
Vol 70 (1) ◽  
Author(s):  
Saurabh Dubey ◽  
Ketki Patil ◽  
Pooja Sharma ◽  
Ghanshyam D. Tandon
Keyword(s):  
High Performance ◽  
Antimicrobial Agents ◽  
Fold Increase ◽  
Multidrug Resistant ◽  
Submerged Cultivation ◽  
Chromatography Analysis ◽  
Gram Positive Bacteria ◽  
Lactam Ring ◽  
Single Compound ◽  
Potassium Clavulanate

AbstractThere is an urgent need to discover new anti-microbial agents that can overcome the increasing antibiotic resistance posed by multidrug resistant, β-lactamase producing bacteria. β-Lactam antibiotics are structurally related through the presence of a core β-lactam ring. Resistant pathogens are able to produce β-lactamase enzymes that hydrolyze the β-lactam ring and inactivate the antibiotic. One approach to counteract this resistance is to develop β-lactamase inhibitors, which, on administration with β-lactams, restores the antibiotic activity for its continued clinical use. In the present study, a fungal Penicillium strain was isolated, identified and characterized for its antimicrobial and β-lactamase inhibition activities. The strain was identified as Penicillium piceum and was grown in suitable media under submerged cultivation. The antibacterial activity was observed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Higher antimicrobial activity was observed against gram-positive bacteria as compared to gram-negative bacteria. A certain amount of antifungal activity was also observed against the fungal strains of Penicilium chrysogenum, Rhizopus stolonifer, Fusarium moniliforme, Aspergillus niger, Giberella fujikuroi and Saccharomyces cerevisiae. Iodometric and bioassay analyses confirmed that P. piceum produced β-lactamase inhibitors having activity against penicillinase (Bacillus cereus). Solvent-solvent extraction with butanol yielded a three-fold increase in β-lactamase inhibition activity. High-performance liquid chromatography analysis of the concentrated product proved it to be a single compound. The infrared (IR) spectrum of the compound was compared with the reference IR spectra of sulbactam sodium, tazobactam and potassium clavulanate. It was found to be different thereby inferring the need for extensive structural elucidation for future applications.

Effects of a muramyl dipeptide on the temperature and sleep-wake cycles of the squirrel monkey

1984 ◽  
Vol 247 (4) ◽  
pp. R672-R680
Author(s):  
D. B. Wexler ◽  
M. C. Moore-Ede
Keyword(s):  
Rem Sleep ◽  
Muramyl Dipeptide ◽  
Sleep Time ◽  
Time Of Day ◽  
Saline Control ◽  
Sleep Stages ◽  
Base Line ◽  
Percent Time ◽  
Subjective Night ◽  
Control Injection

The circadian sleep-wake and body temperature cycles of squirrel monkeys were monitored continuously in an environment free of time cues before and after a 50-nmol injection of a synthetic muramyl dipeptide (MDP) either 1 h after wake-up time (subjective day) or just before sleep time (subjective night). At both phases decreases in percent time awake (relative to saline controls) were observed. After administration of MDP early in the subjective day, the animals exhibited alert wakefulness only 47.4% of the daytime, compared with a mean 86.7% of daytime after a saline control injection. The transitional stage was significantly elevated from 6.2 to 28.7% of time after MDP. Nonrapid-eye-movement (REM) sleep was elevated in four of five animals, but in the fifth animal, which had the least consolidated base-line sleep-wake pattern, a small decrease in non-REM sleep was seen. Regression analysis demonstrated a significant (P less than 0.01) relationship between the degree of sleep-wake consolidation and the effect of MDP on non-REM sleep. Normal sleep behaviors and spontaneous arousals were observed. MDP given at the circadian nighttime of two animals resulted in sleep and transitional episodes occupying 84% of the subjective night vs. 73% of time asleep after control injection. Again, these were mostly transitional and non-REM sleep stages, and they persisted 4–5 h into the predicted circadian daytime. REM sleep appeared to be suppressed in the early hours after injection at either time of day.(ABSTRACT TRUNCATED AT 250 WORDS)

Function of rat hepatocyte tight junctions: studies with bile acid infusions

1991 ◽  
Vol 260 (1) ◽  
pp. G167-G174
Author(s):  
W. G. Hardison ◽  
E. Dalle-Molle ◽  
E. Gosink ◽  
P. J. Lowe ◽  
J. H. Steinbach ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Bile Acid ◽  
Bile Acids ◽  
Bile Flow ◽  
Biliary Tree ◽  
Isolated Hepatocytes ◽  
Paracellular Permeability ◽  
Molecular Weights ◽  
Charge Selectivity ◽  
Constant Rate

To determine the effects of alteration of biliary paracellular permeability on bile flow and composition, we measured the biliary outputs of compounds highly concentrated in bile, all infused at a constant rate in the isolated rat liver perfused with Krebs-Henseleit buffer in a one-pass fashion. Paracellular permeability was increased by infusing 10(-8) M vasopressin (VP). The cholephilic compounds were three cations of various molecular weights, tributylmethylammonium (TBuMA), N-acetylprocainamide ethobromide (APAEB), and propidium iodide, and two anions, taurocholate (TC), a micelle-forming bile acid, and taurodehydrocholate (TDHC), an nonmicelle former. When TC was infused and paracellular permeability increased with VP, neither bile flow nor TC output changed, whereas outputs of cations fell. When TDHC was infused, TDHC output fell, as did outputs of all cations. The decrements in cation outputs exceeded that of TDHC and were inversely related to the molecular weight of the cation. To document that these changes were not related to reduced uptake of these compounds, we tested the uptakes of TBuMA, APAEB, and TDHC into isolated hepatocytes. In no case did 10(-8) M VP significantly reduce uptake. The data demonstrate that micelle-forming bile acids, with their high effective molecular weights, do not efflux from the biliary tree when permeability is increased with VP, whereas nonmicelle-forming bile acids do. Cations efflux more readily than anions, and within this group efflux rate is inversely related to molecular weight. The data confirm the size and charge selectivity of biliary tree permeability.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Intestinal growth-promoting properties of glucagon-like peptide-2 in mice

1997 ◽  
Vol 273 (1) ◽  
pp. E77-E84 ◽  
Author(s):  
C. H. Tsai ◽  
M. Hill ◽  
S. L. Asa ◽  
P. L. Brubaker ◽  
D. J. Drucker
Keyword(s):  
Cell Proliferation ◽  
Fold Increase ◽  
Crypt Cell ◽  
Saline Control ◽  
Intestinal Epithelial ◽  
Intestinal Growth ◽  
Crypt Cell Proliferation ◽  
Term Administration ◽  
Glucagon Like Peptide

Glucagon-like peptide-2 (GLP-2) has been shown to promote intestinal epithelial proliferation. We studied crypt cell proliferation, enterocyte cell death, and feeding behavior in GLP-2-treated mice. GLP-2 had no effect on food consumption [7.7 +/- 0.3 vs. 8.0 +/- 0.4 g/day, saline (control) vs. GLP-2-treated mice, P = not significant]; however, GLP-2 increased the crypt cell proliferation rate (46.0 +/- 1 vs. 57 +/- 5%, control vs. GLP-2, P < 0.01) and decreased the enterocyte apoptotic rate (5.9 +/- 0.7 vs. 2.8 +/- 0.2% apoptotic cells, control vs. GLP-2, P < 0.05) in small bowel (SB) epithelium. GLP-2 induced a significant increase in SB weight (1.3- to 1.75-fold increase over control, P < 0.05 to P < 0.001) in mice 1-24 mo of age. Increased SB weight was maintained after daily administration of GLP-2 to mice for 12 wk, and cessation of GLP-2 administration in older mice led to regression of (increased) SB weight and mucosal height. These observations suggest that GLP-2 regulates both cell proliferation and apoptosis and promotes intestinal growth after both short- and long-term administration in vivo.

Effects of Na+ replacement and amiloride on ursodeoxycholic acid-stimulated choleresis and biliary bicarbonate secretion

1987 ◽  
Vol 252 (2) ◽  
pp. G163-G169 ◽  
Author(s):  
J. R. Lake ◽  
R. W. Van Dyke ◽  
B. F. Scharschmidt
Keyword(s):  
Bile Acid ◽  
Ursodeoxycholic Acid ◽  
Bile Flow ◽  
Acid Output ◽  
Fold Increase ◽  
Isolated Perfused Rat Liver ◽  
Bicarbonate Secretion ◽  
Bile Formation ◽  
Li Substitution ◽  
Stimulation Of

In these studies, we have tested the hypothesis that bile acid-dependent bile formation is attributable, in part, to the stimulation of active bicarbonate secretion and have further explored the cellular mechanism(s) possibly involved in this process using the isolated perfused rat liver. Under control conditions, ursodeoxycholic acid (UDCA) infusion (3 mumol/min X 20 min) produced a 3.7-fold increase in bile flow and a 7.4-fold increase in HCO3- output. Amiloride (an inhibitor of Na+-H+ exchange) decreased UDCA-stimulated bile flow by 20.6% and decreased biliary HCO3- output by 24.9% but increased biliary UDCA output by 42.9%. Thus amiloride decreased UDCA choleretic efficiency (microliter UDCA-stimulated bile/mumol UDCA output) by 45% and UDCA-stimulated increase in HCO3- output per unit UDCA secreted by 48%. Substitution of Li+ for Na+ in perfusate virtually abolished (greater than 95% decrease) both the UDCA choleresis and increase in biliary HCO3- output but modestly decreased (39.6%) biliary bile acid output. Li+ substitution thus decreased UDCA choleretic efficiency by 98% and the UDCA-stimulated increase in HCO3- output by 96%. Amiloride had no effect and Li+ substitution produced a modest decrease in basal bile flow (26.0%) and HCO-3 output (33.5%). Neither amiloride nor Li+ substitution significantly affected UDCA uptake by cultured hepatocytes or by perfused liver. Amiloride (1 mM) also decreased taurocholate (TC)-stimulated choleresis by 48.5%, biliary TC output by 7.2%, and the choleretic efficiency of TC by 45%.(ABSTRACT TRUNCATED AT 250 WORDS)

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