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PubMed1989

A randomized trial of adjuvant progestagen in early endometrial cancer.

A randomized, controlled trial was designed to determine whether adjuvant progestagen therapy improves survival in patients with Stage I or Stage II endometrial cancer. After surgery, 1148 patients were randomly assigned to adjuvant treatment with progesterone or were given no additional therapy. The duration of follow-up ranged from 42 to 132 months (median follow-up, 72 months). Crude survival and relapse rates were similar for both groups. Death due to intercurrent disease was higher in the progesterone group (P = 0.04). The median survival of the group of patients with cancer-related death was higher in the progestagen group than in the control group (30 and 22 months, respectively; P = 0.03). In 461 high-risk patients, a tendency towards fewer cancer-related deaths and a better disease-free survival in the treatment group was observed, but crude survival was unchanged. We conclude that there is little to gain from adjuvant progestagen therapy in patients with low-risk endometrial cancer, and that further studies are needed in high-risk patients.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed2001

Superior muscle reinnervation after autologous nerve graft or poly-L-lactide-epsilon-caprolactone (PLC) tube implantation in comparison to silicone tube repair.

Recovery after peripheral nerve injury depends not only on the amount of reinnervation, but also on its accuracy. The rat sciatic nerve was subjected to an 8 mm long gap lesion repaired either by autograft (AG, n = 6) or tubulization with impermeable silicone tube (SIL, n = 6) or permeable tube of poly-L-lactide-epsilon-caprolactone (PLC, n = 8). Recordings of the compound muscle action potential (CMAP) from gastrocnemius (mGC), tibialis anterior (mTA) and plantar (mPL) muscles were performed 90 days after injury to assess the amount of muscle reinnervation. The CMAP amplitude achieved in mGC, mTA and mPL was similar in after nerve autograft (39%, 42%, 22% of control values) and PLC tube implantation (37%, 36%, 24%) but lower with SIL tube (29%, 30%, 14%). The nerve fascicles projecting into each of these muscles were then transected and retrograde tracers (Fluoro Gold, Fast Blue, DiI) were applied to quantify the percentage of motoneurons with single or multiple branches to different targets. The total number of labeled motoneurons for the three muscles did not differ in autografted rats (1186 +/- 56; mean +/- SEM) with respect to controls (1238 +/- 82), but was reduced with PLC tube (802 +/- 101) and SIL tube (935 +/- 213). The percentage of neurons with multiple projections was lower after autograft and PLC tube (6%) than with SIL tube (10%). Considering the higher CMAP amplitude and lower number of neurons with multiple projections, PLC nerve conduits seem superior to SIL tubes and a suitable alternative to autografts for the repair of long gaps.

Animals↗
PubMedDate not supplied

Bacterially produced apolipoprotein D binds progesterone and arachidonic acid, but not bilirubin or E-3M2H.

Apolipoprotein D (ApoD) constitutes an atypical lipoprotein in so far as it is predominantly found associated with HDL particles but belongs to the lipocalin structural family. Apart from its involvement in serum lipid transport it is abundant in various tissues, and differing physiological functions have been ascribed to it. We have now developed an E. coli expression system that permits the efficient production of biochemically homogeneous ApoD via secretion into the bacterial periplasm. Detailed ligand binding studies by fluorescence titration revealed that progesterone and arachidonic acid are complexed with dissociation constants both in the 1 microM range, whereas the presumed ligands pregnenolone, bilirubin and E-3M2H are not recognized by the recombinant protein. In contrast with previous reports it thus appears that ApoD discriminates well in its binding function between closely related compounds.

Apolipoproteins↗
PubMed2000

Progestagens for endometrial cancer.

OBJECTIVES: Progestagen therapy following primary surgery for endometrial cancer has been advocated to reduce the risk of recurrence. The objective of this review was to assess the effect of adjuvant progestagen therapy in endometrial cancer. SEARCH STRATEGY: We searched the Cochrane Gynaecological Cancer Group trials register and MEDLINE up to May 1999. SELECTION CRITERIA: Randomised trials of progestagen therapy in women who have had surgery for endometrial cancer. DATA COLLECTION AND ANALYSIS: Trial quality was assessed and two reviewers abstracted data independently. MAIN RESULTS: Six trials involving 4351 women were identified. Three trials included women with stage one disease only, whereas three included women with more advanced disease. Based on five trials, overall survival was not improved by adjuvant progestagen therapy (OR 1.05, 95% CI 0.88 to 1.24). Endometrial cancer deaths and relapse of disease appears to be reduced by progestagen therapy OR 0.88 95% CI (0.71-1.1) and 0. 81 95% CI (0.65-1.01) respectively. However, non-endometrial cancer related deaths were more common in women treated with progestagens OR 1.33 (1.02-1.73). REVIEWER'S CONCLUSIONS: Current evidence does not support the use of adjuvant progestagen therapy in the primary treatment of endometrial cancer.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed2001

Biocatalytic reduction of beta,delta-diketo esters: a highly stereoselective approach to all four stereoisomers of a chlorinated beta,delta-dihydroxy hexanoate.

A stereoselective chemoenzymatic synthesis of all four stereoisomers of tert-butyl 6-chloro-3,5-dihydroxy-hexanoate (6a) is presented. The key step of the sequence is a highly regio- and enantioselective single-site reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (1a) by two enantiocomplementary biocatalysts. Alcohol dehydrogenase from Lactobacillus brevis (recLBADH) afforded a 72% yield of enantiopure tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate [(S)-2a]. The enantiomer (R)-2a was prepared with 90-94% ee by Baker's yeast reduction in a biphasic system (50% yield). Both biotransformations were performed on a gram scale. The beta-keto group of the enantiomeric delta-hydroxy-beta-keto esters 2a thus obtained was reduced by syn- and anti-selective borohydride reductions. Permutation of the reduction methods yielded all four stereoisomers of the crystalline target compound 6a (> or = 99.3% ee, dr > or = 205:1), which is a versatile 1,3-diol building block. recLBADH accepts a variety of beta,delta-diketo esters as was determined in a photometric assay. tert-Butyl 3,5-dioxo-hexanoate (1b) and tert-butyl 3,5-dioxo-heptanoate (1c) were reduced on a preparative scale as well to afford the corresponding delta-hydroxy-beta-keto esters (R)-2b and (R)-2c with 99.4% ee and 98.1% ee, respectively.

Bacteria↗
PubMed1983

Inhibition of cold insolubility of an IgA cryoglobulin by decanedicarboxylic acid and related compounds.

Cold insolubility of a serum IgA cryoimmunoglobulin was found to be inhibited by the addition of 1.5 mM sodium decanedicarboxylate in vitro. The patient with the cryoglobulin had advanced multiple myeloma complicated by severe hyperviscosity that caused lethargy and episodic loss of consciousness. Decanedicarboxylic acid administered orally resulted in transient relief of symptoms and the loss of cryoprecipitability of the paraprotein. Further in vitro studies revealed that sodium salts of long-chain monocarboxylic acids with a minimum of eight carbons, and dicarboxylic acids with a minimum of 12 carbons inhibited cryoprecipitation. Salts of short-chain carboxylic acids, by contrast, enhanced cryoprecipitation. Sodium phenolate and sodium salts of benzoic acid, 2,4-DNP, phenylpropionic acid, and salicylic acid were also inhibitory. These latter compounds, which have a ring structure, did not cause precipitation at any concentration. It was demonstrated that the presence of a free carboxylic group was required for these activities; conversion of carboxylic acid to amide resulted in the loss of both the inhibitory and cryoprecipitation-enhancing effects. Normal plasma, or plasma from five other patients who had IgG, IgM, or mixed-type cryoglobulinemia, were not affected by any of these compounds. It is suggested that in selected cases of hyperviscosity syndrome associated with cryoglobulinemia, some of these compounds, especially monocarboxylic acids with appropriate chain lengths, or those with a ring structure, may have therapeutic applications.

Acetamides↗
PubMed2006

Melt electrospinning of poly-(ethylene glycol-block-epsilon-caprolactone).

Various block copolymers of poly(ethylene glycol) and poly(epsilon-caprolactone) (PEG-b-PCL) with molecular weights between 7000 and 26,900 g/mol were synthesized, and melt electrospun at temperatures between 60 degrees C and 90 degrees C. Two types of fibers were collected, including excellent quality fibers - highly coiled and continuous, with a constant diameter and relatively defect free. Such fibers, termed "solid fibers", were sufficiently cooled during their path between the spinneret and the collector that the symmetric fiber shape is maintained after landing on the collector. The second type of melt electrospun fiber were poor quality, large diameter fibers, flattened on the collector - termed "molten fibers". The solid and molten fibers were morphologically distinct from each other as determined from scanning electron microscopy (SEM). Using an SEM imaging method to assess the regional variations of collected electrospun material, we found the spinneret pump rate largely influenced the fiber quality. The polymer flow rate to the spinneret and the molecular weight of PEG-b-PCL had the greatest effect on the electrospun fibers collected, with an optimum rate of 0.05-0.1 mL/h for the highest molecular weight copolymers. The lowest molecular weight PEG-b-PCL tended to electrospray, while the material collected from higher molecular weight copolymers were conducive to fiber formation. The highest quality fibers were PEG-b-PCL block copolymers (22,000 and 26,900 g/mol) melt electrospun at temperatures of 85 degrees C and 90 degrees C, corresponding to shear viscosities of the polymer of between 28.1 and 39.4 Pa.S.

Biocompatible Materials↗
PubMed2005

Preparation of chitosan-g-polycaprolactone copolymers through ring-opening polymerization of epsilon-caprolactone onto phthaloyl-protected chitosan.

The new biodegradable chitosan graft copolymer, chitosan-g-polycaprolactone, was synthesized by the ring-opening graft copolymerization of epsilon-caprolactone onto phthaloyl-protected chitosan (PHCS) at the hydroxyl group in the presence of tin(II) 2-ethylhexanoate catalyst via a protection-graft-deprotection procedure. Toluene acted as a swelling agent in this heterogeneous system. The grafting reactions were conducted with various PHCS/monomer/toluene feed ratios to obtain chitosan-g-polycaprolactone copolymers with various polycaprolactone contents. The chemical structure of the chitosan-g-polycaprolactone was characterized by Fourier transform infrared and one- and two-dimensional NMR spectroscopy. After deprotection, the phthaloyl group was removed and the amino group was regenerated. Thus the obtained chitosan-g-polycaprolactone was an amphoteric hybrid with a large amount of free amino groups and hydrophobic polycaprolactone side chains. Some properties of the final product were also investigated, such as crystallinity, thermal property, and solubility.

Amino Acids↗
PubMed2002

Computer-aided real-time estimation of reaction conversion for lipase-catalyzed esterification in solvent-free systems.

Real-time conversion estimation through macroscopic balancing was investigated for enzymatic esterification reactions in a solvent-free system. In principle, the conversion of ester synthesis can be determined from the amount of water produced by the reaction because water is formed as a by-product in the same molar ratio as the product. In this study, we show that the water production rate, and thereby the reaction conversion, can be estimated on-line from measurements of the relative humidity of the inlet and outlet air and the material balances of water in the system. In order to test the performance of the real-time conversion estimation method, the lipase-catalyzed esterification reaction of n-capric acid and n-decyl alcohol in solvent-free media was conducted while controlling the water activity at various values. When the reaction conversions estimated on-line were compared with those analyzed off-line by gas chromatography, good agreement was obtained: the average mean absolute error was +/- 2.4% of the reaction conversion despite the simplicity of the method. The on-line estimation method presented here requires no expensive or complicated analytical instruments and no sampling of reaction medium. It can be used for monitoring nonaqueous enzymatic reactions where water is produced or consumed during reaction.

Algorithms↗
PubMed2003

Mechanistic limitations in the synthesis of polyesters by lipase-catalyzed ring-opening polymerization.

Lipase-catalyzed polymerization of caprolactone (CL) in toluene with methoxy-poly(ethylene glycol) (MPEG) and water as initiators was characterized in detail for mechanistic insight. (1)H NMR analysis of polycaprolactone chains (PCL), dicaprolactone, degree of esterification of MPEG, and fractions of PCL chains initiated by MPEG and water were used to follow the reactions. The data were analyzed with the kinetic scheme involving formation of the acylenzyme and its consequent reaction with MPEG, water, or PCL to yield the MPEG- or water-initiated PCL chains, or increase in PCL length. A limit for MPEG initiator esterification in lipase-catalyzed CL polymerization was observed and was explained by preferential reaction of PCL propagation over MPEG esterification at long reaction times and low MPEG concentrations. Slower monomer conversion in concentrated monomer solutions was explained by decreased partitioning of PCL between the solvent and the enzyme. This effect resulted in inhibition of the lipase by the reaction product, PCL chains, and/or insufficient diffusion of monomer to the enzyme active site. High monomer/initiators ratio in these solutions did not yield longer polymer chains due to decreased monomer conversion and the corresponding decrease in product yields; lower yields were also observed for chain initiation by MPEG and water. A shift in the reaction rate-limiting step from formation of acylenzyme in dilute CL solutions to its deacylation in concentrated CL solutions yielded higher PCL polydispersity due to increased initiation by water. Enhanced intramolecular cyclization was also observed. Endgroup composition of PCL chains was influenced by the concentration of monomer, ratio of initiators (MPEG and water), and reaction time, yielding PCL chains initiated exclusively by MPEG at "infinite reaction times."

Caproates↗
PubMed1978

Toxic effects of fatty acids on yeast cells: possible mechanisms of action.

As shown in a previous paper, threshold concentrations of lower and intermediate fatty acids inhibit the uptake of inorganic phosphate, growth, and cell division in yeast cells. This demonstrates that, apart from these effects, the acids cause an increase in the respiration quotient (RQ), inhibition of CO2 fixation, production of ethanol at the expense of anabolic processes, and inhibition of active amino acid transport in the yeast Candida utilis. On the other hand, the threshold concentrations have no effect on intracellular pH. The inhibition of the inorganic phosphate uptake cannot be the sole primary mode of action of fatty acids since the omission of inorganic phosphate in the incubation medium brings about an inhibition of anabolic processes that is lower than that brought about by fatty acids since the omission of inorganic phosphate in the incubation medium brings about an inhibition of anabolic processes that is lower than that brought by fatty acids at concentrations still premitting some phosphate uptake. Although 2,4-dinitrophenol and caproic acid at low concentrations cause an analogous decrease in biomass yield, their combination does not bring about any marked increase in the effect. Considering the physicochemical properties of fatty acids and their preferential action on energy-requiring processes, one of the key sites of action can be assumed to be the mitochondrial membrane. Fatty acids might inhibit the transport of anions, especially phosphate, across the membrane, and disturb the membrane potential by affecting the transport protons. The physiocochemical properties of fatty acids may also give rise to their binding to other intracellular membranes and to a subsequent interference with the function of the corresponding organelles.

Aminoisobutyric Acids↗
PubMed1992

Randomized, controlled study evaluating effects of branched chain amino acids and alpha-ketoisocaproate on protein metabolism after surgery.

The effect of nutritional supplementation with branched chain amino acids or the ketoacid alpha-ketoisocaproate on protein metabolism after surgery was studied in 24 patients with gastrointestinal cancer. They were randomized to receive one of three nutritional regimens. All patients received a balanced amino acid solution and group 1 (n = 8) received no further supplements, group 2 (n = 8) received supplementation with alpha-ketoisocaproate (17 g day-1) and group 3 (n = 8) received a branched chain solution including leucine, isoleucine and valine, corresponding to 3.3 g nitrogen day-1. Plasma albumin, prealbumin, fibronectin and serum urea concentrations, nitrogen balance and 3-methylhistidine release from the leg and its excretion in the urine were measured. Albumin and prealbumin concentrations fell after surgery in all groups, and fibronectin levels fell in group 2 (P less than 0.001). In group 2 there was also a significant increase in serum urea concentration after operation (P less than 0.05). Cumulative nitrogen balance after 3 days was -5.6 g (group 1), -3.8 g (group 2) and -1.7 g (group 3). The release of 3-methylhistidine (nmol 100 g-1 min-1) from the leg after operation, following an overnight fast, was -0.42 (group 1), -0.51 (group 2) and -0.66 (group 3). During infusion the release was -0.56, -0.99 and -0.81, respectively. A balanced amino acid solution with an adequate energy supply has an optimal nitrogen-sparing effect. Branched chain amino acids or alpha-ketoisocaproate did not improve nitrogen balance or reduce protein degradation.

Amino Acids, Branched-Chain↗