Identification of chalcones as in vivo liver monofunctional phase II enzymes inducers

Cancer preventive agents (CPA) are drugs able to suppress the carcinogen metabolic activation or block the formation of ultimate carcinogens. CPA could act through various molecular mechanisms, for example by interfering with the action of procarcinogen. This could be attained by increasing the phase II enzymes levels of quinone reductase (QR) and glutathione S-transferase (GST). New flavonoids, especially chalcones, have been identified as in vivo monofunctional phase II enzymes inducers. Oral administration of chalcone, 4, and both p-methoxy-substituted chalcones, 6 and 14, increased hepatic QR activity with concomitant decrease in CYP1A1 activity, a member of the most important group of phase I enzymes cytochrome P450. Among them, 4 also increased GST activity. While p-bromo-substituted chalcone 8 was the best inducer of QR it decreased hepatic GST expression and cytochrome P450, being the most effective decreasing cytochrome P450-expression. Thienyl-chalcone 20 being the bioisostere of chalcone 4 did not display the same in vivo profile in the phase I level modification. As chalcone 4 its bioisostere, chalcone 20, displayed low DNA strand breakage and absence of mutagenicity. Also, in our preliminary in vivo tumourigenesis/chemopreventive and acute-toxicity studies, chalcones 4, 6 and 8 showed the best behaviours as CPA justifying additional studies that are ongoing.     

Coexpression of virulence and fosfomycin susceptibility in Listeria: molecular basis of an antimicrobial in vitro-in vivo paradox

Discrepancies between resistance in vitro and therapeutic efficacy in vivo are generally attributed to failure of laboratory susceptibility tests to reflect an antibiotic's pharmacokinetic or pharmacodynamic properties. We show here that this phenomenon can result from differential in vitro-in vivo expression of bacterial determinants of antibiotic susceptibility. We found that an in vivo-induced virulence factor, Hpt, also mediates uptake of fosfomycin in Listeria monocytogenes. These bacteria therefore seem resistant to fosfomycin in vitro, although they are in fact susceptible to the antibiotic during infection.     

Cardiovascular risk of young growth-hormone-deficient adolescents. Differences in growth-hormone-treated and untreated patients

OBJECTIVE: To determine whether postprandial lipids, coagulation factors and homocysteine levels are abnormal in young growth hormone (GH)-deficient (GHD) adolescents. METHODS: Fifteen GHD adolescents on GH replacement were studied. Ten untreated GHD adolescents and 15 healthy subjects served as controls. Fasting lipids, lipoprotein(a), fibrinogen, plasminogen activator inhibitor-1, homocysteine, folate and vitamin B12 levels were measured. Cholesterol and triglycerides were measured 4 h after a high fat meal. RESULTS: Fasting and postprandial triglycerides and homocysteine levels of untreated GHD patients were increased compared to those of GH-treated GHD subjects and healthy controls; fibrinogen concentrations were elevated in both treated and untreated adolescents. CONCLUSIONS: GHD adolescents present an abnormal fasting and postprandial lipid profile. In addition, the increased fibrinogen and homocysteine levels are suggestive of the accumulation of cardiovascular risk factors early on in life.     

Optimization of biomass, total carotenoids and astaxanthin production in Haematococcus pluvialis Flotow strain Steptoe (Nevada, USA) under laboratory conditions

The microalga Haematococcus pluvialis Flotow is one of the natural sources of astaxanthin, a pigment widely used in salmon feed. This study was made to discover optimal conditions for biomass and astaxanthin production in H. pluvialis from Steptoe, Nevada (USA), cultured in batch mode. Growth was carried out under autotrophic (with NaNO3, NH4Cl and urea) and mixotrophic conditions (with 4, 8, 12 mM sodium acetate) under two photon flux densities (PFD) (35 and 85 mumol m-2 s-1). The carotenogenesis was induced by 1) addition of NaCl (0.2 and 0.8%), 2) N-deprivation and 3) high PFD (150 mumol m-2 s-1). Total carotenoids were estimated by spectrophotometry and total astaxanthin by HPLC. Ammonium chloride was the best N-source for growth (k = 0.7 div day-1, 228-258 mg l-1 and 2.0 x 10(5)-2.5 x 10(5) cells ml-1 at both PFD, respectively). With increasing acetate concentration, a slight increment in growth occurred only at 85 mumol m-2 s-1. Light was the best inductive carotenogenic factor, and the highest carotenoid production (4.9 mg l-1, 25.0 pg cell-1) was obtained in cultures pre-grown in nitrate at low light. The NaCl caused an increase in carotenoid content per cell at increasing salt concentrations, but resulted in a high cell mortality and did not produce any increment in carotenoid content per volume compared to cultures grown at 150 mumol m-2 s-1. The highest carotenoid content per cell (22 pg) and astaxanthin content per dry weight (10.3 mg g-1) (1% w/w) were obtained at 85 mumol m-2 s-1 with 0.8% NaCl.     

Olfactory sensitivity for carboxylic acids in spider monkeys and pigtail macaques

Using a conditioning paradigm, the olfactory sensitivity of four spider monkeys and four pigtail macaques for a homologous series of carboxylic acids (n-propionic acid to n-heptanoic acid) was investigated. With only few exceptions, the animals of both species significantly discriminated concentrations <1 p.p.m. from the odorless solvent and in several cases individual monkeys even demonstrated thresholds <1 p.p.b. The results showed (i). both primate species to have a well-developed olfactory sensitivity for carboxylic acids, which for some substances matches or even is markedly better than that of species such as the rat or the dog and (ii). a significant correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of the carboxylic acids in both species tested. These findings lend further support to the growing body of evidence suggesting that between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance, and that general labels such as 'microsmat' or 'macrosmat'-which usually are based on allometric comparisons of olfactory brain structures-are inadequate to describe a species' olfactory capabilities.     

Biocatalyst-adsorbant systems: a viable alternative to proteolytic processes in solution

Proteolytic biocatalysts were adsorbed and stabilized using alumina as a support medium. Two biocatalyst-adsorbant systems were prepared with different physical characteristics of the adsorbant: alumina powder and alumina pearls. Direct adsorption onto the support medium has the main advantage, over other fixation methods, that preliminary steps are not required for a good interaction between the support and the biocatalyst. Proteases were adsorbed and stabilized without modifying or sterically hindering their active sites. Parameters affecting adsorption (pH, temperature, ionic strength) were varied so as to optimize adsorption conditions. Operational viability of the immobilized biocatalysts was demonstrated, taking into account the rate of desorption, resistance to microbial attack, and stability during storage. Desorption in water was studied in batch and continuous-flow processes, at various flow rates. The systems also proved to be resistant to microorganisms. Tests for stability during storage found the systems' activity remained constant after 60 days, and they performed better than biocatalysts in solution. Proteolysis of a solution of g per litre of azocasein was carried out in continuous-flow and batch modes, using our biocatalyst-adsorbant systems we prepared. In all cases, free amino group concentrations were around 2.5 times greater after treatment with biocatalyst-adsorbants than they were in the starting solution.     

Effectiveness of multiple-site EMG biofeedback in the reduction of arousal

During the training phase, 36 subjects received (a) EMG biofeedback from multiple muscle sites, (b) EMG biofeedback from the frontal site, or (c) no biofeedback. Results indicated that neither biofeedback procedure reduced self-reports of anxiety, but that multiple-site biofeedback was effective in reducing several indices of autonomic arousal (pulse rate, finger pulse volume, and skin temperature) while frontal biofeedback was not. During the generalization/stress phase, all subjects were threatened with and received electric shocks and were told to apply the relaxation techniques they learned during the training phase even though no additional biofeedback would be provided. Results indicated that multiple-site biofeedback was effective in reducing self-reports of anxiety and autonomic arousal but that frontal biofeedback was not. These results confirm previous data indicating that frontal biofeedback is not an effective procedure for controlling stress, but suggest that EMG biofeedback can be effective in reducing self-reported anxiety and autonomic arousal if a multiple muscle-site feedback procedure is employed.     

Comparison of ITS RFLP patterns of Gracilaria (Rhodophyceae, Gracilariales) populations from Chile and New Zealand and an examination of interfertility of Chilean morphotypes

Restriction fragment length polymorphism (RFLP) patterns of the internal transcribed spacer (ITS) of the nuclear ribosomal cistron and crossability trials were used to characterize four morphotypes of Gracilaria from Lenga, Isla Santa María and Maullín, Chile, and two morphotypes from sites in New Zealand. PCR products from all Chilean morphotypes resulted in a major single band of ca. 1198 bp. ITS-RFLP profiles generated with the restriction enzymes Cla I, Hae III, Pst I, Hha I, Rsa I and Taq I, were identical in all cases. All crosses within, as well as between, morphotypes resulted in cystocarp differentiation, with the production of viable carpospores. Based upon these data, it is concluded that the four morphotypes from Chile correspond to a single species, G. chilensis, and that the ITS-RFLP pattern is a useful marker to predict genetic relatedness at the specific level in Gracilaria. A comparison of the ITS-RFLP patterns of the Chilean morphotypes with the patterns of two samples of G. chilensis from New Zealand revealed that the sample from Scorching Bay, Wellington, fits the Chilean ITS-RFLP patterns. The population from Blockhouse Bay, Auckland, appears to correspond to another species. This revised version was published online in July 2006 with corrections to the Cover Date.