Occurrence, biosynthesis, and biodegradation of pivalic acid and other compounds, having a quaternary carbon atom by different bacteria, are described. We have summarized the relevant data that have so far been published, presenting them in a graphical form, i.e., as biodegradation pathways including B₁₂-dependent isomerization and desaturation that lead to the degradation of pivalic acid and similar compounds to products with other than quaternary carbon atoms, i.e., compounds whose catabolism is well known.

• MeSH
• Bacteria genetika   metabolismus   MeSH
• biosyntetické dráhy * MeSH
• kyseliny pentanové chemie   metabolismus   MeSH
• metabolické sítě a dráhy MeSH
• molekulární struktura MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• kyseliny pentanové MeSH
• pivalic acid MeSH Prohlížeč

A biosynthetic pathway using pivalic acid as a starter unit was found in three bacterial species, Alicyclobacillus acidoterrestris, Rhodococcus erythropolis and Streptomyces avermitilis. When deuterium-labelled pivalic acid was added to A. acidoterrestris and R. erythropolis nutrient media it was incorporated into fatty acids to give rise to tert-butyl fatty acids (t-FAs). In addition, in R. erythropolis, pivalic acid was transformed into two starter units, i.e. isobutyric and 2-methylbutyric acid, which served as precursors of corresponding iso-even FAs and anteiso-FAs. In S. avermitilis the biosynthesis also yielded all three branched FAs; apart from this pathway, both pivalic and 2-methylbutyric acids were incorporated into the antibiotic avermectin.

• MeSH
• Alicyclobacillus metabolismus   MeSH
• antibakteriální látky biosyntéza   MeSH
• butyráty metabolismus   MeSH
• ivermektin analogy a deriváty   metabolismus   MeSH
• kyseliny pentanové metabolismus   MeSH
• mastné kyseliny biosyntéza   MeSH
• Rhodococcus metabolismus   MeSH
• Streptomyces metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2-methylbutanoic acid MeSH Prohlížeč
• antibakteriální látky MeSH
• avermectin MeSH Prohlížeč
• butyráty MeSH
• ivermektin MeSH
• kyseliny pentanové MeSH
• mastné kyseliny MeSH
• pivalic acid MeSH Prohlížeč

The paper presents the results of an analytical evaluation and a study of some physicochemical properties of a new potential drug of the prodrug type--the substance BL 443 pivalate with an assumed antidysrhythmic effect. The structure of the substance has been confirmed by elemental analysis, IR and UV spectroscopy. The following parameters were determined: melting point, solubility, dissociation constant, experimental partition coefficient in four different systems, and surface activity. The chromatographic behaviour of the drug on a thin layer (adsorption and partition chromatography) was also investigated. Acidimetric titration in non-aqueous medium and spectrophotometry in the ultraviolet region of the spectrum at the wavelength of the second absorption maximum of the drug was employed to determine the content of the drug in pure substance.

• MeSH
• antiarytmika chemie   MeSH
• chemické jevy MeSH
• fyzikální chemie MeSH
• prekurzory léčiv chemie   MeSH
• valeráty chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ((2-pivaloyloxy-3-isopropylamine)propoxy)phenycarbamic acid, butyl ester MeSH Prohlížeč
• antiarytmika MeSH
• prekurzory léčiv MeSH
• valeráty MeSH

Biological effectiveness of antiviral acyclic nucleoside phosphonate adefo vir, 9-[2-(phosphonomethoxy)ethy]ade nine (PMEA) and its more lipophilic (bis)pivaloyloxymethyl ester prodrug adefovir dipivoxil (bis-POM-PMEA) were compared under in vitro conditions in mammalian cell systems. Proliferation of murine splenocytes was inhibited in a concentration-dependent manner, the bis-POM-PMEA being more effective than PMEA. In contrast to PMEA, bis-POM-PMEA inhibited production of nitric oxide (NO) in macrophages activated with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). Viability of both splenocytes and macrophages remained uninfluenced by PMEA, whereas pronounced cytocidal effects were exhibited by bis-POM-PMEA. The IC(50)s reached the values of 15 microM and 30 microM in cultures of macrophages and splenocytes, respectively (assayed at the interval of 24 hrs). The effects could partly be mimicked by formaldehyde, a decomposition product of the pivoxil moiety of bis-POM-PMEA. The other possible product, pivalic acid, was ineffective in this respect. The present data are consistent with the view that pivoxil prodrug of PMEA, bis-POM-PMEA possesses enhanced but also broader spectrum of biological effects than the parent compound.

• MeSH
• adenin analogy a deriváty   toxicita   MeSH
• antivirové látky toxicita   MeSH
• inhibitory reverzní transkriptasy toxicita   MeSH
• kultivované buňky MeSH
• lymfocyty účinky léků   MeSH
• makrofágy účinky léků   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• organofosfonáty toxicita   MeSH
• oxid dusnatý metabolismus   MeSH
• prekurzory léčiv toxicita   MeSH
• proliferace buněk účinky léků   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• adefovir dipivoxil MeSH Prohlížeč
• adefovir MeSH Prohlížeč
• adenin MeSH
• antivirové látky MeSH
• inhibitory reverzní transkriptasy MeSH
• organofosfonáty MeSH
• oxid dusnatý MeSH
• prekurzory léčiv MeSH

Electrophoretic focusing on an inverse electromigration dispersion profile is a relatively new electrophoretic separation method for the analysis of ionisable analytes. Although it offers alternative selectivity, powerful concentration capability and high sensitivity, so far only several systems for the analysis of anionic compounds were reported. This work describes for the first time a functional electrolyte system for the separation of cationic analytes by this method. Based on computer simulations and calculations, a functional electrolyte system was designed, based on 1-ethylpiperazine and pivalic acid. It is suitable for the analysis of weak bases with pKa values between 4.5 and 6 and due to the volatility of both components, it can be operated in combination with ESI-MS detection. Its practical applicability is demonstrated on direct analysis of four 2-hydroxy-s-triazines in waters. Separation in an uncoated capillary with application of negative pressure at the inlet provides very satisfactory results with good reproducibility of peak areas, peak heights and detection times, and with LODs at the 0.5-1 nM (100 ngL-1) level. The robustness of the method is shown on analyses of real tap and river water samples used without any pretreatment.

• Klíčová slova
• Capillary electrophoresis, ESI-MS detection, Electrophoretic focusing, Triazine herbicides, Weak bases,
• MeSH
• anionty MeSH
• elektroforéza kapilární * MeSH
• kationty MeSH
• reprodukovatelnost výsledků MeSH
• triaziny * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anionty MeSH
• kationty MeSH
• triaziny * MeSH

Dietetic treatment of Crohn's disease has the objective to calm down the gut either by a polymeric or elemental diet. In superacute conditions also total parenteral nutrition can be used. In the quiescent stage the patient must have an adequate energy intake and a low-residue (low-fibre) diet. As to medication, sulfasalazine which has some side-effects is abandoned and 5-ASA (5-aminosalicylic acid) preparations are used, either by the oral route or in enemas, while 4-ASA is little used in this country and is known as PAS. The administration of corticoids which also have side-effects will be abandoned in favour of so-called rapidly metabolized corticoids (Tixocortol pivalate, beclomethasone, budenoside and fluticasone) by the oral route and in enemas and foams. As antimicrobial treatment ciprofloxacine is used combined with metronidazole. As to immunosuppressive drugs azathioprine, 6-mercaptopurine, cyclosporin A, cyclophosphamide and methotrexate are tested. A hope for the future is so-called biological treatment (anticytokines, monoclonal antibodies against cytokines, against CD4+ TNF, interleukines IL-10 and 11, immunoglobulin; plasmapheresis is also tested). Treatment must be individual and surgery as late as possible, only in case of complications, and should be very sparing, stenoses should be treated by plastic operations of strictures.

• MeSH
• Crohnova nemoc terapie   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• přehledy MeSH