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PubMed2000

Improved sensitivity proteomics by postharvest alkylation and radioactive labelling of proteins.

We describe approaches to improve the detection of proteins by postharvest alkylation and subsequent radioactive labeling with either [3H]iodoacetamide or 125I. Database protein sequence analysis suggested that cysteine is not suitable for detection of the entire proteome, but that cysteine alkylating reagents can increase the number of proteins able to be detected by iodination chemistry. Proteins were alkylated with beta-(4-hydroxyphenyl)ethyl iodoacetamide, or with 1,5-l-AEDANS (the Hudson Weber reagent). Subsequent iodination using the Iodo-Gen system was found to be most efficient. The enhanced sensitivity obtainable by using these approaches is expected to be sufficient for visualization of the lowest copy number proteins from human cells, such as from clinical samples. However, we argue that significantly improved methods of protein separation will be necessary to resolve the large number of proteins expected to be detectable with this sensitivity.

Acetamides↗
PubMed2004

Colorado potato beetles compensate for tomato cathepsin D inhibitor expressed in transgenic potato.

We reported earlier the importance of digestive cathepsin D-like activity for initiating dietary protein hydrolysis in Colorado potato beetle, Leptinotarsa decemlineata Say [Brunelle et al. (1999) Arch. Insect Biochem. Physiol. 42:88-98]. We assessed here whether transgenic lines of potato (Solanum tuberosum L.) expressing a cathepsin D inhibitor (CDI) from tomato would show resistance to the beetle, or if the insect would compensate for the loss of cathepsin D activity after ingesting the recombinant inhibitor. Transgenic potato lines expressing tomato CDI were developed by Agrobacterium tumefaciens genetic transformation, and selected based on their relative amount of CDI. After confirming the absence of detectable visible effects of CDI on the plant's phenotype, diet assays with control and transgenic lines were carried out to assess the impact of the inhibitor on growth and development of the insect. Leaf consumption, relative growth rate, molting incidence, and digestive protease activity were monitored at 12-h intervals over 132 h for 3rd-instar larvae provided with transgenic potato foliage. Leaf consumption and relative growth rate were slightly reduced during the first 12 h for larvae fed CDI, but no significant differences were observed thereafter. In contrast, time for molting to the 4th larval stage was significantly longer for larvae fed modified plants, with developmental delays of approximately 10 h (0.5 day) compared to control larvae. Recombinant CDI also had an impact on the insect's digestive physiology, readily inducing overproduction of digestive proteases (rubiscases), followed by a gradual decrease of total and pepstatin-sensitive activity. Overall, these observations show the ability of Colorado potato beetle to compensate for the loss of cathepsin D activity by modulating its digestive protease complement in response to aspartate-type inhibitors in the diet. From a practical viewpoint, these data stress the importance of devising improved strategies for the effective inhibition of insect digestive proteinases in vivo, based on the use of hybrid inhibitors active against different protease classes.

Animal Feed↗
PubMed1992

[Aqueous chloramine T solutions as disinfectants: chemical composition, reactivity and toxicity].

In aqueous solutions of Chloramine T (CAT), caused by dissociation, hydrolysis and disproportionation processes, seven different kinds of molecules emerge (HOCl, OCl-, R-NCl-, R-NHCl, R-NCl2, R-NH2, and R-NH- [R = CH3-C6H4-SO2]). Their equilibrium concentrations have been calculated using an iteration process (polynom of 4th degree) as a function of cCAT (0.003-10%) and pH (0-14): The (absol.) concentration of "free chlorine" ([HOCl] + [OCl-]) is surprisingly low showing a maximum concentration of HOCl in the whole concentration and pH range of only 2 . 10(-7) moles/l (0.014 ppm). The relative equilibrium concentrations of the N-chlorinated toluene sulfonamide species R-NCl-, R-NHCl, and R-NCl2, virtually alone responsible for the oxidizing and by this also disinfecting properties, owing to the extremely low concentration of free chlorine, are influenced in the concentration range relevant for practice (greater than 0.1%) only by the pH-value: At pH greater than 7 the whole oxidation capacity is present as R-NCl- (pH 7: 99.6%; pH 8: 99.96%), while at pH less than 3 it is formed by R-NHCl and R-NCl2.(ABSTRACT TRUNCATED AT 250 WORDS)

Chloramines↗
PubMed2004

A novel spectrophotometric determination of some phenothiazines involving iodine monochloride from chloramine-T with iodine.

A novel, simple, sensitive spectrophotometric method is proposed for the determination of five phenothiazines. Chloramine-T with iodine in acetic acid produces iodine monochloride which oxidizes phenothiazines to absorbing cations. Those would associate later with unreacted ICl to form an ion pair, [Ph+] [ICl-(2)] in hydrochloric acid medium. These appear to provide exceptional color stability to the systems. A probable mechanism along with experimental stoichiometry and stability constants of such ion pairs is indicated. The method is not only successful in stabilizing the color of the systems, but also in making a unique observation of two regions of concentration of phenothiazines adhering separately to Beer's law. The results obtained from the analyses of pure samples and their drug formulations in both regions of concentration are comparable with those obtained either with a reported titrimetric method or with a British Pharmacopoeia (B.P.) UV-spectrophotometric method. The conditions required for the quantitative determination of phenothiazines are described and related analytical parameters are also calculated.

Chloramines↗
PubMed1989

Synthesis and structural studies of N-p-toluensulfonyl cyclodipeptides.

In view of the chemical and structural interest of cyclopeptides bearing an electron withdrawing substituent directly bonded at the amide nitrogen atom, the two N-p-toluensulfonyl (N-tosyl) derivatives cyclo[-Phe(Tos)-D-Phe-] (I) and cyclo[-Phe(Tos)-D-Pro-] (II) have been synthesized and their stereochemistry defined. The molecular structure of I, as determined by x-ray diffraction analysis, is reported together with 1H-nmr parameters indicating the preferred rotameric conformation in chloroform solution. The N-tosyl group alters the geometry of the cyclodipeptide ring by lengthening both the N-C bonds departing from the tosylated nitrogen and reducing the corresponding ring angle. The 6-membered peptide ring adopts an unusual "sofa" conformation with the Tos-Phe C alpha atom deviating 0.230(3) A out of the mean plane of the other five ring atoms. One of the two S-O bonds forms a planar system that involves the tosylated nitrogen and the corresponding amide carbonyl. In the crystal, both the benzylic side chains are folded over the heterocyclic ring, whereas in chloroform solution, the benzylic side chain of the D-Phe prefers an extended conformation.

Dipeptides↗
PubMed2004

Acid zeolites as alcohol racemization catalysts: screening and application in biphasic dynamic kinetic resolution.

Acid zeolites were screened as heterogeneous catalysts for racemization of benzylic alcohols. The most promising zeolites appeared to be H-Beta zeolites, for which the optimal reaction conditions were studied in further detail. The zeolite performance was compared to that of homogeneous acids and acid resins under similar reaction conditions. In a second part of the research, H-Beta zeolites were applied in dynamic kinetic resolution (DKR) of 1-phenylethanol, which was conducted by means of a two-phase approach and which resulted in yields smoothly crossing the 50% border up to 90%, with an enantiomeric excess of >99%. To explore the applicability of this biphasic methodology, several other substrates were examined in the standard racemization reaction and in the biphasic dynamic kinetic resolution.

Catalysis↗
PubMed2001

Enantioconvergent synthesis of (-)-(S)- and (+)-(R)-2-acetyl-3,6-dihydroxycyclohex-2-enone starting from rac-6-hydroxy-3-methoxycyclohex-2-enone.

The synthesis of enantiomerically pure (-)-(S)- and (+)-(R)-2-acyl-3,6-dihydroxycyclohex-2-enone starting from diastereomerically pure N-tosyl-(S)-proline esters 3-methoxy-6-hydroxycyclohex-2-enone 1 is presented. An enantioconvergent synthesis of either (-)-(S)- and (+)-(R)-2-acyl-3,6-dihydroxycyclohex-2-enone starting with the racemic alpha-ketol 1 through a conversion of ( approximately 1:1) mixture of diastereomeric esters into one diastereomer by a repeated crystallization, followed by dimethylaminopyridine-catalyzed equilibration as key steps is described.

Cyclohexanols↗
PubMed1988

Two monoclonal antibodies to actin: one muscle selective and one generally reactive.

Two IgG1, kappa monoclonal antibodies (Mab) against actin have been obtained from a fusion in which chicken gizzard actin was used as the immunogen. One Mab, designated B4, shows a preferential reactivity toward enteric smooth muscle actin but also cross-reacts with skeletal, cardiac, and aorta actins on the basis of immunoblots, ELISA assays, and indirect immunofluorescence. However, this antibody does not react with either cytoplasmic actin in any of these assay systems. A second Mab, designated C4, reacts with all six known vertebrate isoactins as well as Dictyostelium discoideum and Physarum polycephalum actins. Thus B4 Mab appears to react with an epitope that is at least partially shared among the muscle actins but not found in cytoplasmic actins, while C4 Mab binds to an antigenic determinant that has been highly conserved among the actins. The binding sites of both Mabs on skeletal actin overlap that of pancreatic DNase I. Both antibodies bind a SV8 proteolytic product comprising the amino-terminal two-thirds of the actin molecule, and their epitopes appear to overlap since C4 can compete for the binding of B4 to skeletal actin. Neither antibody is able to prevent actin polymerization.

Actins↗
PubMed2003

Diagnosis and management of treatment-related osteoporosis in men with prostate carcinoma.

Osteoporosis is a complication of androgen deprivation therapy in men with prostate carcinoma. Androgen deprivation therapy, caused by either bilateral orchiectomy or treatment with a gonadotropin-releasing hormone agonist, decreases bone mineral density and increases fracture risk. Other factors including diet and lifestyle may contribute to bone loss. There is limited information regarding the best strategy to prevent osteoporosis in men with prostate carcinoma. Lifestyle modification including smoking cessation, moderation of alcohol consumption, and regular weight-bearing exercise should be encouraged. Supplemental calcium and vitamin D are also recommended. Additional treatment may be warranted for men with osteoporosis, fractures, or high rates of bone loss during androgen deprivation therapy. Intravenous pamidronate, a second-generation bisphosphonate, prevents bone loss during androgen deprivation therapy. Zoledronic acid, a more potent third-generation bisphosphonate, not only prevents bone loss but also increases bone mineral density during androgen deprivation therapy. Other bisphosphonates may be effective although they have not been evaluated in this clinical setting. Treatment with estrogens or selective estrogen receptor modulators may also be effective. Monotherapy with bicalutamide or other antiandrogens may cause less bone loss than androgen deprivation therapy.

Absorptiometry, Photon↗
PubMed2003

Impact of a novel neoadjuvant and adjuvant hormone-deprivation approach on quality of life, voiding function, and sexual function after prostate brachytherapy.

BACKGROUND: Data demonstrate a benefit from neoadjuvant and adjuvant hormone-deprivation therapy with luteinizing hormone-releasing hormone agonists in patients who are treated with radiotherapy for localized prostate carcinoma; however, this approach has detrimental effects on quality of life (QOL). A cross-sectional study was undertaken to evaluate the impact on QOL, voiding function, and sexual function of an alternative hormone-deprivation approach. METHODS: Three hundred fifty patients with clinical T1c-T2b prostate carcinoma were treated from March 1997 to August 2000 either with palladium 103 brachytherapy (BTM) without hormone therapy or with 8 months of adjuvant and neoadjuvant hormone-deprivation therapy with an antiandrogen and finasteride (BTM+H), were mailed the Functional Assessment of Cancer Therapy (FACT) global well being QOL instrument (FACT-G), the American Urological Association symptom score (AUASS), and specific items addressing urinary control and sexual function from validated instruments. Differences between treatment groups were assessed as a function of time since treatment. RESULTS: Seventy-two percent of patients responded to the questionnaire. No differences in overall FACT-G scores, AUASS scores, or AUASS subscale scores between the BTM group and the BTM+H group were found. The BTM+H group initially had lower personal well being FACT-G subscale scores, more urinary incontinence, and lower odds of attaining an erection sufficient for intercourse initially, although these differences disappeared with longer follow-up. CONCLUSIONS: The use of neoadjuvant and adjuvant antiandrogen and finasteride with brachytherapy is associated with QOL equal to that of brachytherapy alone for the treatment of patients with localized prostate carcinoma, allowing the advantages of hormone manipulation in terms of tumor control without its downside.

5-alpha Reductase Inhibitors↗
PubMed2004

Androgen ablation therapy for prostate carcinoma suppresses the immunoreactive telomerase subunit hTERT.

BACKGROUND: Telomerase is a ribonucleoprotein complex that protects the ends of chromosomes from degradation. Its catalytic subunit, hTERT, controls its activity. Prior data in prostate carcinoma cases indicated that immunohistochemical hTERT reactivity increases with tumor grade and may be absent in lower grade cases. The effect of complete androgen ablation (CAA) on tumor hTERT expression was uncertain. METHODS: hTERT immunostaining was performed on the cancerous pretreatment biopsy tissue of 30 men who consecutively underwent CAA with bicalutamide and goserelin acetate for 30 days prior to undergoing radical prostatectomy, and on their tumor tissue from radical prostatectomy. As controls, biopsy and prostatectomy samples from 30 untreated men were studied. Nuclear staining was evaluated by two observers, and the change in staining between biopsy and prostatectomy samples was evaluated using the Student t test in both groups. RESULTS: The percent of reactive tumor nuclei in treated men declined from 36.7% to 13.2% (P = 0.0001), and declined from 19.8% to 16.1% in untreated men (P = 0.4). The greater mean hTERT reactivity in the treated men's biopsy specimens was attributed to an increased proportion of higher (Gleason score > or = 7) grade tumors. The decline in hTERT immunostaining remained significant after normalizing it to that of the untreated group (P = 0.002). The original Gleason scores, corresponding declines in the percentage of reactive tumor nuclei, and significance were: Gleason score < or = 6: 11% (P = 0.03); Gleason score of 7: 23% (P < 0.006); and Gleason score > or = 8: 46% (P < 0.005) (from a mean 63% to 17%). CONCLUSIONS: CAA for prostate carcinoma can be considered an antitelomerase therapy. The steepest reduction in telomerase activity was noted in the highest grade tumors.

Aged↗