Showing papers by "Rhône-Poulenc published in 1995"

Docetaxel (Taxotere): a review of preclinical and clinical experience. Part I: Preclinical experience.

Abstract: Docetaxel is a taxoid which is currently in phase II/III clinical trials in Europe, the US and Japan. It was found to promote tubulin assembly in microtubules and to inhibit their depolymerization. In vitro, the docetaxel concentrations required to reduce murine and human cell survival by 50% ranged from 4 to 35 ng/ml and the cytotoxic effects were greater on proliferating than on non-proliferating cells. It was also found to be cytotoxic on fresh human tumor biopsies. In vivo, the drug was found to be schedule independent. A total of 13/14 murine transplantable tumors were found very sensitive to i.v. docetaxel and complete regressions of advanced stage tumors were obtained. Activity was also observed in 15/16 human tumor xenografts in nude mice at an advanced stage. In combination studies, synergism was observed in vivo with 5-fluorouracil, cyclophosphamide and etoposide. Pharmacokinetic evaluation revealed linear pharmacokinetics in tumor-bearing mice. There was a good tumor retention with a 22 h elimination half-life. Plasma protein binding ranged from 76 to 89%. Preclinical toxicology evaluation of docetaxel included single-dose toxicity in rats, mice and dogs, 5-day toxicity in mice and dogs, intermittent-dose toxicity in rats, dogs and monkeys, genetic and reproductive toxicity, as well as investigation of the irritation and sensitization potential. The principal toxicities were hematopoietic (all species), gastrointestinal (dog, monkey) and neuromotor (mice). Dogs appeared to be the most sensitive species. The clinical entry dose of 5 mg/m2 was based on one-third of the 'toxic dose low' in dogs (15 mg/m2).

Analysis of gyrA and grlA mutations in stepwise-selected ciprofloxacin-resistant mutants of Staphylococcus aureus.

Abstract: Fluoroquinolone-resistant mutants were obtained in vitro from Staphylococcus aureus RN4220 by stepwise selection on increasing concentrations of ciprofloxacin. Results from sequence analysis of the quinolone resistance-determining region of GyrA and of the corresponding region of GrlA, the DNA topoisomerase IV subunit, showed an alteration of Ser-80 to Tyr (corresponding to Ser-83 of Escherichia coli GyrA) or Glu-84 to Lys in GrlA of both low- and high-level quinolone-resistant mutants. Second-step mutants were found to have, in addition to a mutation in grlA, reduced accumulation of norfloxacin or an alteration in GyrA at Ser-84 to Leu or Glu-88 to Lys. Third-step mutants derived from second-step mutants with reduced accumulation were found to have a mutation in gyrA. The results from this study demonstrated that mutations in gyrA or mutations leading to reduced drug accumulation occur after alteration of GrlA, supporting the previous findings (L. Ferrero, B. Cameron, B. Manse, D. Lagneaux, J. Crouzet, A. Famechon, and F. Blanche, Mol. Microbiol. 13:641-653, 1994) that DNA topoisomerase IV is a primary target of fluoroquinolones in S. aureus.

Field-Induced Structures in Ferrofluid Emulsions.

Abstract: The field-induced structure in a monodisperse ferrofluid emulsion is studied. An applied magnetic field induces a magnetic dipole moment in each droplet. When the dipole-dipole interaction energy exceeds the thermal energy, a phase transition occurs as the fluid of randomly dispersed droplets changes to a solid of nearly equally sized and spaced columns. Our results show that the column spacing follows a relation ${d\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.33L}^{0.37}$ for cell thickness $3\ensuremath{\le}L\ensuremath{\le}800\ensuremath{\mu}\mathrm{m}$. A new theory, which treats the column shape more realistically, is developed to account for the results.

Hyperhomocysteinemia-Induced Vascular Damage in the Minipig Captopril-Hydrochlorothiazide Combination Prevents Elastic Alterations

Abstract: Background Previous attempts in animals failed to reproduce the metabolic, pathological, and clinical situations encountered in homocystinuric patients. Minipigs on a methionine-rich caseinate-based diet, however, have a special long-lasting postprandial plasma accumulation of methionine, the metabolic precursor of homocysteine. We hypothesized that these minipigs develop hyperhomocysteinemia in the long term. Angiotensin-converting enzyme (ACE) inhibition prevents atherogenic alteration of viscoelastic functions of arterial pulsatility and compliance and reduces fragmentation of vascular elastic laminae in the minipigs. We consequently analyzed the therapeutic effects of the captopril-hydrochlorothiazide combination against the typical hyperhomocysteinemia-induced alterations of vascular elastic features. Methods and Results Thirty-two Gotingen minipigs were randomized as control diet-fed (C), captopril (25 mg/d)/hydrochlorothiazide (12.5 mg/d)-treated C (C+Cp), caseinate-based diet-fed (M), and M+Cp mi...

Cloning, pharmacological characterization, and anatomical distribution of a rat cDNA encoding for a galanin receptor

Abstract: We have cloned and expressed a rat cDNA, designated GALR1-rat, that encodes a galanin receptor based on homology, pharmacology, and anatomical criteria. This cDNA was isolated from a rat brain cDNA library. The nucleotide sequence of the cloned receptor revealed an open reading frame encoding a 346-amino-acid protein, showing 90.8% identity with the previously cloned human galanin receptor. Membranes prepared from COS cells transiently expressing GALR1-rat specifically bind125I-galanin with high affinity (K d=0.12±0.01 nM). Rat, porcine, and human galanin were able to displace125I-galanin with nanomolar Ki (0.08±0.03, 0.10±0.01, and 0.14±0.03 nM, respectively), whereas the Ki values for the porcine galanin fragments galanin-(1–16), galanin-(2–29), and galanin-(3–29) were 0.95±0.21 nM, 7.14±0.51 nM, and >1 µM, respectively. The rank order potency of these ligands is consistent with that reported for the native galanin receptor. The distribution of the mRNA corresponding to the galanin receptor encoded by GALR1-rat was determined byin situ hybridization to rat brain sections. High levels of galanin receptor mRNA were detected in the ventral hippocampal formation, thalamic, amygdala, and medulla oblongata nuclei, and in the dorsal horn of the spinal cord.

Comparison of the pharmacokinetic profiles of three low molecular mass heparins--dalteparin, enoxaparin and nadroparin--administered subcutaneously in healthy volunteers (doses for prevention of thromboembolism).

Abstract: The present trial was designed to comparatively investigate the pharmacokinetic profile and evaluate the apparent bioavailability pattern of three already marketed low molecular mass heparins (LMMHs): dalteparin (Fragmin®), nadroparin (Fraxiparin®), and enoxaparin (Love- nox®) given by subcutaneous route. The study was carried out in 20 healthy young volunteers given, according to a cross over design, a single subcutaneous injection of the doses recommended for the prophylaxis of deep vein thrombosis (commercial preparations, prefilled syringes): dalteparin 2,500 IU (= 2,500 IU anti-Xa), nadroparin 7,500 ICU (= 3,075 IU anti-Xa), enoxaparin 20 mg (= 2,000 IU anti-Xa) and enoxaparin 40 mg (= 4,000 IU anti-Xa). Of the markers used, activated partial thromboplastin time (APTT), thrombin clotting time (TCT), Heptest®, anti-thrombin (aIIa) activity and anti-Xa (aXa) activity, the most pertinent parameter (from a biodynamic viewpoint) is plasma aXa activity. We demonstrated that dalteparin, nadroparin and enoxaparin exhibit statistically significantly different pharmacokinetic and overall disposition patterns. Normalized to the same injected dose (1,000 IU aXa), the relative actual amount of plasma anti-Xa activity generated by enoxaparin is 1.48 times greater (p

Tissue-Specific Expression of Germin-Like Oxalate Oxidase during Development and Fungal Infection of Barley Seedlings

Abstract: Oxalate oxidase activity was detected in situ during the development of barley seedlings. The presence of germin-like oxalate oxidase was confirmed by immunoblotting using an antibody directed against wheat germin produced in Escherichia coli, which is shown to cross-react with barley (Hordeum vulgare) oxalate oxidase and by enzymatic assay after electrophoresis of the protein extracts on polyacrylamide gels. In 3-d-old barley seedlings, oxalate oxidase is localized in the epidermal cells of the mature region of primary roots and in the coleorhiza. After 10 d of growth, the activity is detectable only in the coleorhiza. Moreover, we show that oxalate oxidase is induced in barley leaves during infection by the fungus Erysiphe graminis f. sp. hordei but not by wounding. Thus, oxalate oxidase is a new class of proteins that responds to pathogen attack. We propose that oxalate oxidase could have a role in plant defense through the production of H2O2.

Thermal stability of doped ceria: experiment and modelling

Abstract: The process of the decrease of the surface area due to crystallite growth in ceria at 943 K is described by a kinetic model involving oxygen and cerium diffusion. The experimentally found variations in the rate of crystallite growth are reported as a function of the content (⩽ 10% cat.) of dopants, which are the cations Ca2+, Mg2+, Al3+, Y3+, Sc3+, Al3+, Th4+, Zr4+ and Si4+. The variations are discussed on the basis of the diffusion of cerium vacancies as the rate-limiting step, and on the basis of calculated expressions of the concentrations of oxygen vacancies, electrons and cerium vacancies vs. the oxygen partial pressure and the dopant content. For cations that are smaller than Ce4+, the comparison between the experimental and theoretical rates asserts the validity of the model and allows the prediction of the efficiency of a cation to stabilize the surface area, from its associations with oxygen vacancies and with the electron-bearing species, Ce′Ce.

Production of gamma linolenic acid by a delta-6 desaturase

Abstract: Linoleic acid is converted into γ-linolenic acid by the enzyme Δ6-desaturase. The present invention is directed to isolated nucleic acids comprising the Δ6-desaturase gene. More particularly, the isolated nucleic acid comprises the promoter, coding region and termination regions of the Δ6-desaturase gene. The present invention provides recombinant constructions comprising the Δ6-desaturase coding region in functional combination with heterologous regulatory sequences. The nucleic acids and recombinant constructions of the instant invention are useful in the production of GLA in transgenic organisms.

Analysis of the nucleic acid annealing activities of nucleocapsid protein from HIV-1.

Abstract: Retroviral nucleocapsid (NC) protein is an integral part of the virion nucleocapsid where it is in tight association with genomic RNA and the tRNA primer. NC protein is necessary for the dimerization and encapsidation of genomic RNA, the annealing of the tRNA primer to the primer binding site (PBS) and the initial strand transfer event. Due to the general nature of NC protein-promoted annealing, its use to improve nucleic acid interactions in various reactions can be envisioned. Parameters affecting NC-promoted nucleic acid annealing of NCp7 from HIV-1 have been analyzed. The promotion of RNA:RNA and RNA:DNA annealing by NCp7 is more sensitive to the concentration of MgCl2 than the promotion of DNA:DNA hybridization. Stimulation of complex formation for all three complexes was efficient at 0-90 mM NaCl, between 23 and 55 degrees C and at pH values between 6.5 and 9.5, inclusive. Parameters affecting NCp7-promoted hybridization of tRNA(Lys,3) to the PBS, which appears to be specific for NC protein, will be discussed. Results implicate the basic regions of NCp7, but not the zinc fingers, in promoting the annealing of complementary nucleic acid sequences. Finally, NCp7 strand transfer activity aids the formation of the most stable nucleic acid complex.

Thermal stability of a high surface area ceria under reducing atmosphere

Abstract: The influence of a reducing atmosphere on the thermal stability of CeO2 was studied on a high surface area ceria sample (115 m2 g−1) treated 2 h under hydrogen or carbon monoxide at various temperatures between 673 and 1123 K. Comparative experiments were done under air or vacuum, and also in presence of water or carbon dioxide in order to estimate the relative importance of the reduction products. An important decrease of the specific surface area was observed between 850 and 1000 K under air, vacuum, carbon monoxide or water pressure, the residual BET area being below 10 m2 g−1 at 1100 K. Under hydrogen, the same loss of surface was obtained at ca. 150 K lower temperatures. In all cases, the first step was the elimination of the microporosity followed by the growth of the crystallites. The peculiar influence of hydrogen was related to the high concentration of lattice oxygen vacancies created during the reduction of the bulk. In the case of carbon monoxide atmosphere which also reduces the sample, the carbonate species formed during the reduction are eliminated from the bulk at higher temperatures, which explain the better resistance to sintering compared to hydrogen. This was confirmed by a treatment under carbon dioxide atmosphere which was found to preserve the specific surface area better because of the stabilization of the carbonate species on the ceria.

Taxoids, their preparation and pharmaceutical compositions containing them

Abstract: Novel taxoids of general formula (I), the preparation thereof and pharmaceutical compositions containing same, are disclosed. In general formula (I), Z is a hydrogen atom or a radical of general formula (II), wherein R1 is an optionally substituted benzoyl radical or a radical R2-O-CO-, where R2 is an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, bicycloalkyl, optionally substituted phenyl or heterocyclyl radical; R3 is an alkyl, alkenyl, alkynyl, cycloalkyl, phenyl, naphthyl or aromatic heterocyclic radical; R4 is a hydroxy radical or an alkoxy, alkenyloxy, optionally substituted alkynyloxy, alkanoyloxy, alkenoyloxy, alkynyloxy, alkoxyacetyl or alkyloxycarbonyloxy radical, or a cycloalkyloxy, cycloalkenyloxy, arylcarbonyloxy or heterocyclylcarbonyloxy radical; and R5 is an optionally substituted alkoxy radical or a cycloalkyloxy or cycloalkenyloxy radical. The novel compounds of general formula (I), wherein Z is a radical of general formula (II), have remarkable antitumoral and antineoplastic properties.

Vitamin B12: How the Problem of Its Biosynthesis Was Solved

Abstract: Vitamin B12 is an essential vitamin for human health, and lack of it leads to pernicious anemia. This biological activity has attracted intense interest for some time; in addition, the complex architecture of the B12 molecule has fascinated chemists and biochemists since its discovery as the first natural organocobalt complex and the establishment of its structure by X-ray analysis. The organic ligand surrounding the cobalt displays many stereogenic centers along its periphery carrying reactive functional groups. This complexity led vitamin B12 to be rightly regarded as an extreme challenge to the synthetic chemist. Yet microorganisms achieve this synthesis in vivo with complete control of regio- and stereochemistry. How do they do it? This review tells the full remarkable story. Success in unraveling this biosynthetic puzzle resulted from a collaborative effort by biologists and chemists using the full range of methods available from their disciplines–from genetics at one end of the spectrum to synthesis and NMR spectroscopy at the other. This work can act as a guide for future research on the biosynthesis of yet more complex natural substances.

Chimeric nitrilase-encoding gene for herbicidal resistance

Abstract: A Chimeric gene which is usable for endowing plants with resistance to a herbicide based on 3,5-dihalo-4-hydroxy-benzonitrile, comprising at least one gene coding for resistance to this herbicide, a foreign promoter and, optionally, a polyadenylation signal region, wherein the promoter originates from a gene which is naturally expressed in plant cells and is chosen from the group comprising the promoter of the 35 S RNA for cauliflower mosaic virus (CaMV 35S) and the promoter of the small subunit (SSU) of sunflower (Helianthus annuus) ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO).

Docetaxel: an Active New Drug for Treatment of Advanced Epithelial Ovarian Cancer

Abstract: BACKGROUND: Because of the relative scarcity of natural paclitaxel (Taxol), which has been recently recognized as a highly cytotoxic agent for use in platinum-refractory ovarian cancer, synthetic and semisynthetic substitutes have been actively pursued. Docetaxel (Taxotere), a new semisynthetic taxoid, has been selected for clinical development because it is twice as potent as paclitaxel in promoting assembly of tubulin and in inhibiting microtubule depolymerization. Docetaxel also shows equal or greater cytotoxicity in relevant preclinical models. PURPOSE: Because docetaxel has produced consistent antitumor responses in ovarian cancer patients in phase I trials, we planned and conducted a phase II clinical trial to evaluate the drug's effectiveness and its toxic effects. METHODS: The present trial, which started in May 1992 and ended in December 1992, involved 97 patients with advanced epithelial ovarian cancer. The target study population had disease relapse or disease progression within 12 months of the last administration of a first-line or second-line platinum-based regimen with at least one bidimensionally measurable target lesion. The patients received docetaxel at a dose of 100 mg/m2 given as a 1-hour infusion every 3 weeks without premedication for minimizing potential hypersensitivity. Docetaxel-induced side effects were graded according to the National Cancer Institute's Common Toxicity Criteria. RESULTS: The overall response rate was 23.6% in 76 assessable patients versus 20% if all 90 eligible patients were included in the comparison (95% confidence interval [CI] = 11%-29%). Among 34 eligible patients whose tumor progressed on the most recent platinum treatment, the response rate was 23.5% (95% CI = 8%-39%). The median progression-free survival for all eligible patients was 3.9 months, and the median overall survival was 8.4 months. Docetaxel-associated toxicity in 90 assessable patients consisted of short-lived neutropenia in 81 (90%) patients, which was complicated by fever and hospitalization in seven (8%); hypersensitivity reactions were seen in 29 (31%) patients, with significant reactions seen in seven (8%); and neurotoxicity in 43 (48%) patients, with grade 3 or above toxicity seen in only three (3%). The treatment also produced skin reactions in 58 (64%) patients, of whom only four (4%) showed the intensity of grade 3. Eleven (12%) patients experienced pleural effusions, which were the effects of the drug considered to be of greatest concern. Peripheral edema and weight gain due to fluid retention were reported in 40 (44%) and 17 (19%) patients, respectively. CONCLUSION: Docetaxel appears to be effective in the treatment of platinum-refractory ovarian cancer patients.

Compositions containing taxane derivatives

Abstract: This invention relates to compositions containing taxane derivatives, consisting of a solution of such derivatives in a surfactant. These compositions can be used to prepare perfusion solutions.

Anionic surfactants having multiple hydrophobic and hydrophilic groups

Abstract: According to the invention, an improved class of amphoteric surfactant having improved surfactant properties characterized as mild and environmentally safe has been provided comprising compounds of the formula: ##STR1## The amphoteric surfactant of the subject invention have at least two hydrophobic moieties and at least two hydrophilic groups per molecule and are useful as emulsifiers, detergents, dispersants and solubilizing agents.

Nucleic acid-containing composition, its preparation and use

Abstract: Compositions including nucleic acids and cationic oligopeptides capable of forming secondary structures, and their use in therapeutics and gene therapy, in particular for transferring nucleic acids into cells, are disclosed.

Regulation of rat liver apolipoprotein A-I, apolipoprotein A-II and acyl-coenzyme A oxidase gene expression by fibrates and dietary fatty acids

Abstract: The regulation by fibrates and dietary fatty acids of the hepatic gene expression of apolipoproteins (apo) A-I and A-II, the major protein constituents of high-density lipoproteins, as well as of acyl-CoA oxidase, the rate-limiting enzyme of the peroxisomal beta-oxidation pathway, was studied in vivo in the rat and in vitro in primary cultures of rat hepatocytes. In primary hepatocytes, different fibrates decreased apo A-I and increased acyl-CoA oxidase mRNA levels, whereas apo A-II mRNA only decreased in level after treatment with fenofibric acid, but not after bezafibrate, gemfibrozil or Wy-14643 treatment. Treatment with fenofibric acid counteracted the increase in apo A-I mRNA levels observed after dexamethasone or all-trans retinoic acid treatment, whereas simultaneous addition of fenofibric acid together with all-trans retinoic acid or dexamethasone resulted in a superinduction of acyl-CoA oxidase mRNA. Addition of the n-3 polyunsaturated fatty acids (PUFAs), docosanohexaenoic acid and eicosanopentaenoic acid, or the fatty acid derivative alpha-bromopalmitate, decreased apo A-I and increased acyl-CoA oxidase mRNA in a dose-dependent and time-dependent manner, whereas apo A-II mRNA did not change significantly. Nuclear run-on experiments demonstrated that fenofibric acid and alpha-bromopalmitate decreased apo A-I and increased acyl-CoA oxidase gene expression at the transcriptional level. When rats were fed isocaloric diets enriched in saturated fat (hydrogenated coconut oil), n-6 PUFAs (safflower oil) or n-3 PUFAs (fish oil), a significant decrease in liver apo A-I and apo A-II mRNA levels was only observed after fish oil feeding. Compared to feeding low fat, liver acyl-CoA oxidase mRNA increased after fat feeding, but this effect was most pronounced (twofold) in rats fed fish oil. Results from these studies indicate that fish oil feeding reduces rat liver apo A-I and apo A-II gene expression, similar to results obtained after feeding fenofibrate. Fibrates and n-3 fatty acids (and the fatty acid derivative, alpha-bromopalmitate) down-regulate apo A-I and induce acyl-CoA oxidase gene expression through a direct transcriptional action on the hepatocyte. In contrast, only fenofibric acid, but not the other fibrates or fatty acids tested, decrease apo A-II gene expression in vitro.

Purification of the two-enzyme system catalyzing the oxidation of the D-proline residue of pristinamycin IIB during the last step of pristinamycin IIA biosynthesis.

Abstract: High levels of conversion of 14C-labelled pristinamycin IIB (PIIB) to pristinamycin IIA (PIIA) were obtained in vivo in Streptomyces pristinaespiralis and in some other streptogramin A producers. This established that PIIB was an intermediate on the pathway to PIIA. In addition, in vitro studies with cell-free protein preparations demonstrated that the oxidation of PIIB to PIIA is a complex process requiring NADH, riboflavin 5'-phosphate (FMN), and molecular oxygen. Two enzymes were shown to be necessary to catalyze this reaction. Both were purified to homogeneity from S. pristinaespiralis by a coupled enzyme assay based on the formation of PIIA and by requiring addition of the complementing enzyme. One enzyme was purified about 3,000-fold by a procedure including a decisive affinity chromatography step on FMN-agarose. It was shown to be a NADH:FMN oxidoreductase (E.C. 1.6.8.1.) (hereafter called FMN reductase), providing reduced FMN (FMNH2) to the more abundant second enzyme. The latter was purified only 160-fold and was called PIIA synthase. Our data strongly suggest that this enzyme catalyzes a transient hydroxylation of PIIB by molecular oxygen immediately followed by a dehydration leading to PIIA. The native PIIA synthase consists of two different subunits with Mrs of around 50,000 and 35,000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while the FMN reductase seems to be a monomer with a Mr of around 28,000 and containing one molecule of tightly bound FMN. Stepwise Edman degradation of the entire polypeptides or some of their trypsin-digested fragments provided amino acid sequences for the two isolated proteins.

Nucleic acid containing composition, preparation and uses of same

Abstract: Compositions containing one or more nucleic acids and cationic polymers, and their use in gene therapy, particularly for in vivo nucleic acid transfer.