Enhancing the biocompatibility of rhodamine fluorescent probes by a neighbouring group effect.

Fluorescence microscopy is an essential tool for understanding dynamic processes in living cells and organisms. However, many fluorescent probes for labelling cellular structures suffer from unspecific interactions and low cell permeability. Herein, we demonstrate that the neighbouring group effect which results from positioning an amide group next to a carboxyl group in the benzene ring of rhodamines dramatically increases cell permeability of the rhodamine-based probes through stabilizing a fluorophore in a hydrophobic spirolactone state.

Far-red switching DNA probes for live cell nanoscopy.

Herein we present DNA probes composed of Hoechst 33258 and spontaneously blinking far-red hydroxymethyl silicon-rhodamine (HMSiR). The best performing probe, 5-HMSiR-Hoechst, contains the 5'-regioisomer, shows ∼400-fold fluorescence increase upon DNA binding and is compatible with wash-free single molecule localization and 3D stimulated emission depletion microscopy of chromatin nanostructures in living cells.

Efflux pump insensitive rhodamine-jasplakinolide conjugates for G- and F-actin imaging in living cells.

The actin cytoskeleton is crucial for endocytosis, intracellular trafficking, cell shape maintenance and a wide range of other cellular functions. Recently introduced cell-permeable fluorescent actin probes, such as SiR-actin, suffer from poor membrane permeability and stain some cell populations inhomogeneously due to the active efflux by the plasma membrane pumps. We analyzed a series of new probes composed of jasplakinolide and modified rhodamine fluorophores and found that rhodamine positional isomerism has a profound effect on probe performance.

Autonomous bioluminescence imaging of single mammalian cells with the bacterial bioluminescence system.

Bioluminescence-based imaging of living cells has become an important tool in biological and medical research. However, many bioluminescence imaging applications are limited by the requirement of an externally provided luciferin substrate and the low bioluminescence signal which restricts the sensitivity and spatiotemporal resolution. The bacterial bioluminescence system is fully genetically encodable and hence produces autonomous bioluminescence without an external luciferin, but its brightness in cell types other than bacteria has, so far, not been sufficient for imaging single cells.

Rhodamine-Hoechst positional isomers for highly efficient staining of heterochromatin.

Hoechst conjugates to fluorescent dyes are popular DNA stains for live-cell imaging, but the relationship between their structure and performance remains elusive. This study of carboxyrhodamine-Hoechst 33258 conjugates reveals that a minimal change in the attachment point of the dye has dramatic effects on the properties of the final probe. All tested 6'-carboxyl dye-containing probes exhibited dual-mode binding to DNA and formed a dimmer complex at high DNA concentrations.

The fatty acid-bile acid conjugate Aramchol reduces liver fat content in patients with nonalcoholic fatty liver disease.

Background & Aims: We investigated the effects of the fatty acid-bile acid conjugate 3β-arachidyl-amido, 7α-12α-dihydroxy, 5β-cholan-24-oic acid (Aramchol; Trima Israel Pharmaceutical Products Ltd, Maabarot, Israel) in a phase 2 trial of patients with nonalcoholic fatty liver disease (NAFLD).

Methods: We performed a randomized, double-blind, placebo-controlled trial of 60 patients with biopsy-confirmed NAFLD (6 with nonalcoholic steatohepatitis) at 10 centers in Israel. Patients were given Aramchol (100 or 300 mg) or placebo once daily for 3 months (n = 20/group).

Fatty acid bile acid conjugate inhibits hepatic stearoyl coenzyme A desaturase and is non-atherogenic.

Background And Aims: Suppression of stearoyl-coenzyme A desaturase (SCD) activity leads to reduction of obesity, fatty liver as well as of insulin resistance. It was, however, recently reported to enhance atherogenesis. The aim of the present study was to investigate whether inhibition of SCD by Aramchol, a fatty acid bile conjugate with known hypocholesterolemic effects, will affect atherogenesis and how.

Treatment of preestablished diet-induced fatty liver by oral fatty acid-bile acid conjugates in rodents.

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in industrialized countries. It has no accepted medical therapy. Fatty acid-bile acid conjugates (FABACs) were proven to prevent diet-induced NAFLD in rodents.

Hypocholesterolemic effects of fatty acid bile acid conjugates (FABACs) in mice.

Fatty acid bile acid conjugates (FABACs) prevent and dissolve cholesterol gallstones and prevent diet induced fatty liver, in mice. The present studies aimed to test their hypocholesterolemic effects in mice. Gallstone susceptible (C57L/J) mice, on high fat (HFD) or regular diet (RD), were treated with the conjugate of cholic acid with arachidic acid (FABAC; Aramchol).

ABCA1-dependent but apoA-I-independent cholesterol efflux mediated by fatty acid-bile acid conjugates (FABACs).

FABACs (fatty acid-bile acid conjugates) are synthetic molecules that are designed to treat a range of lipid disorders. The compounds prevent cholesterol gallstone formation and diet-induced fatty liver, and increase reverse cholesterol transport in rodents. The aim of the present study was to investigate the effect of FABACs on cholesterol efflux in human cells.

Effects of fatty acid bile acid conjugates (FABACs) on biliary lithogenesis: potential consequences for non-surgical treatment of gallstones.

Fatty acid bile acid conjugates (FABACs) are novel synthetic lipid molecules, which were designed for the treatment of cholesterol gallstones. The rationale was to combine a cholesterol solubilizing moiety (a saturated fatty acid) with a bile acid (cholic acid) as a vehicle to enable secretion into bile and entry into the enterohepatic circulation. An amide bond was used to provide stability against intestinal degradation.

Faecal sterol output is increased by arachidyl amido cholanoic acid (Aramchol) in rats.

Fatty acid-bile acid conjugates (FABACs) were shown recently to have important and multiple effects on cholesterol metabolism. In human fibroblasts, they were found to markedly enhance cholesterol efflux by an ATP-binding cassette transporter A1-dependent pathway. In C57L/J mice, they increased CYP7A1 activity and RNA expression, while decreasing moderately 3-hydroxy-3-methylglutaryl-CoA reductase activity.

Prevention of diet-induced fatty liver in experimental animals by the oral administration of a fatty acid bile acid conjugate (FABAC).

Fatty acid bile acid conjugates (FABACs) are a new family of synthetic molecules designed to solubilize biliary cholesterol. They were shown to prevent and dissolve cholesterol gallstones in inbred C57L/J mice fed a lithogenic, high-fat diet (HFD). In these mice, fatty liver was observed in the controls but not in the FABAC-treated ones.

Biliary and systemic effects of fatty acid bile acid conjugates.

Background: Fatty acid bile acid conjugates (FABACs) are novel synthetic molecules that solubilize cholesterol, prevent cholesterol crystal and gallstone formation, and dissolve pre-existing gallstones in mice. They are thus potential agents for gallstone prevention and treatment. The available knowledge concerning their biliary, systemic or possible toxic effects is, however, incomplete.

Fatty acid bile acid conjugates inhibit atherosclerosis in the C57BL/6 mouse model.

Objective: The aim of the current research was to study whether fatty acid bile acid conjugates (FABACs) have a beneficial effect on atherosclerosis progression and blood lipid levels in mice.

Methods: C57BL/6 female mice, fed a high-fat Paigen diet, were administered an oral dose of FABAC or DDH2O daily. Quantification of atherosclerotic fatty-streak lesions at the aortic sinus was performed.

Dissolution of cholesterol gallstones in mice by the oral administration of a fatty acid bile acid conjugate.

Gallstones, mostly cholesterol stones, affect some 15% of the population. Oral bile salts dissolve human cholesterol gallstones, but with low efficacy, and surgery remains the main therapeutic option. Fatty acid bile acid conjugates (FABACs) were shown to prevent formation of cholesterol gallstones in experimental animals.

Arachidyl amido cholanoic acid (Aramchol) is a cholesterol solubilizer and prevents the formation of cholesterol gallstones in inbred mice.

We have recently synthesized fatty acid bile acid conjugates (FABAC) that were able to reduce and retard cholesterol crystallization in model and human biles. When given orally, they prevented the formation of cholesterol crystals in the bile of hamsters. The aim of the present study was to determine whether the FABAC are cholesterol solubilizers, whether they can dissolve pre-existing crystals, whether they can prevent the formation of cholesterol gallstones, and to investigate the optimal type of bond between the fatty acid and bile acid.

Measles is more prevalent in Crohn's disease patients. A multicentre Israeli study.

The question whether there is a transmissible pathogenetic agent as a cause for Crohn's disease, remains unanswered. Measles virus has been the subject of many intensive studies, in the attempt to find a role for it in the pathogenesis of inflammatory bowel disease. Whether an early infection with measles virus may predispose to Crohn's disease in later life is still not clear.

Effects of current cigarette smoking on clinical course of Crohn's disease and ulcerative colitis.

Cigarette smoking worsens Crohn's disease (CD) but ameliorates ulcerative colitis (UC). In Israel, where there is no epidemiological association of smoking with CD, we examined the effects of current smoking on the course of CD and UC. Patients at nine public hospitals completed a questionnaire detailing their smoking history, disease course and treatments; subjects altering their smoking habit after the onset of disease were excluded.

Appendectomy is more frequent but not a risk factor in Crohn's disease while being protective in ulcerative colitis: a comparison of surgical procedures in inflammatory bowel disease.

Objective: Appendectomy was shown to be protective in patients with ulcerative colitis (UC). There are fewer data in Crohn's disease (CD). Other operations were less studied.

Determination of bile acids in biological fluids by liquid chromatography-electrospray tandem mass spectrometry.

A simple, sensitive, and specific liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the determination of bile acids in human bile has been developed. The bile acids were extracted with a C(18) (octadecyl) reversed-phase column and identified and quantified by simultaneous monitoring of their parent and daughter ions, using the multiple reaction monitoring mode. Identification and quantification of conjugated bile acids in bile was achieved in 5 min.

Fatty acid bile acid conjugates (FABACs)--new molecules for the prevention of cholesterol crystallisation in bile.

Background: Cholesterol gall stones are a frequent disease for which at present surgery is the usual therapy. Despite the importance of bile acids it has become evident that phospholipids are the main cholesterol solubilisers in bile. Even phospholipid components, such as fatty acids, have anticrystallising activity.

Pregnancy and the biliary tract.

Pregnancy induces many physiological changes, some of which may have pathological results. In population studies, gallstones were found in 6.5% to 8.

Passive smoking in patients with inflammatory bowel disease: an Israeli multicentre case-control study.

Background: The association between smoking and inflammatory bowel disease (IBD) is well established. There are, however, no large scale studies of passive smoking in inflammatory bowel disease and this has never been surveyed in the Jewish population of Israel.

Aim: To study the passive smoking exposure of Jewish IBD patients in Israel in a large scale multicentre study.