Browsing by Author "Figueroa, R"

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    Clomazone selectivity among six cucurbit crops
    (COLEGIO POSTGRADUADOS, 2005) Figueroa, R; Kogan, M
    To determine clomazone tolerance of cucurbit crops, at different rates (0.3, 0.45, 0.6 and 0.9 kg ai ha(-1)) and to evaluate weed control efficacy of those treatments, six field studies were conducted in the 1998-1999 season. Clomazone at 0.45 kg ai ha(-1) provided an excellent weed control (>90%) compared with the untreated plots. Yield and number of fruit per plot in all crops were not affected (p <= 0.05) by clomazone treatment regardless of the rate used, except in honeydew (Cucumis melo L. vat. inodorus Naud). As for leaf injury, with the exception of zucchini (Cucurbita pepo L.) and winter squash (C. maxima Duch, Ex. Poiret), all other crops [cucumber (Cucumis sativus L.), honeydew (Cucumis melo L. vat. inodorus Naud), watermelon (Citrullus lanatus Thunb. Matsumara and Nakai) and cantaloupe (Cucumis melo L. vat. reticulatus Naud), exhibited leaf bleaching 10 d after treatment; cantaloupe and watermelon were the least tolerant crops. However, the bleaching effect was transient and did not affect yield. Clomazone can be used selectively as a preemergence herbicide on winter squash, zucchini and cucumber at rates ranging from 0.3 to 0.9 kg ai ha(-1); and on honeydew, watermelon and cantaloupe from 0.3 to 0.6 kg is ha(-1).
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    Differential regulation of μ-opioid receptor mRNA in the nucleus accumbens shell and core accompanying amphetamine behavioral sensitization
    (1999) Vecchiola, A; Collyer, P; Figueroa, R; Labarca, R; Bustos, G; Magendzo, K
    Repeated amphetamine (AMPH) administration results in behavioral sensitization. To investigate the participation of the opioid system in this phenomenon, we examined the effects of acute and repeated AMPH administration on mu-opioid receptor (MOR) mRNA levels in the nucleus accumbens (NAc) and striatum (STR) of rats, by quantitative non-radioactive in situ hybridization. Five injections of PAh IPH (1.5 mg kg(-1), i.p., once every other day), resulted in a sensitization response profile and a significant down-regulation of MOR mRNA levels in the NAc shell, whereas no change was observed in MOR mRNA levels in the NAc core compared to the saline controls. Conversely, MOR mRNA levels were up-regulated in the rostral STR of AMPH-sensitized rats compared to saline controls. No changes in MOR mRNA levels were observed after acute AMPH treatment in any of the brain regions studied. These results suggest that the opioid system participates in the neurobiological underpinnings of behavioral sensitization and that opioid receptor (OR) expression in the STR and NAc shell and core is differentially modulated by repeated AMPH exposure. (C) 1999 Elsevier Science B.V. All rights reserved.
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    High prevalence of thyroid abnormalities in a Chilean psychiatric outpatient population
    (2000) Fardella, C; Gloger, S; Figueroa, R; Santis, R; Gajardo, C; Salgado, C; Barroilhet, S; Foradori, A
    The aim of the present study was to establish the prevalence of thyroid disturbances in patients consulting for panic and mood disorders. These data may be relevant because thyroid functional alterations affect the success of treatment in these pathologies. We studied prospectively 268 psychiatric outpatients (204 females and 64 males) diagnosed by DSM-IV criteria. We excluded patients with addictive disorders and major medical disease. We measured TSH, Free T4 (FT4) and antimicrosomal antibodies (AMA). We diagnosed classical hypothyroidism when the TSH value was >10 mu UI/ml (NV=0.25-4.3) and subclinical hypothyroidism when the TSH value was between 5-10 mu UI/ml. Hyperthyroidism was diagnosed when FT4 >1.4 (NV=0.81.4), the TSH suppressed and the radioiodine uptake >20% (NV=5-15). Positive antimicrosomal antibodies (AMA) titres were >1:100 dilution. Hypothyroidism was diagnosed in 26/268 patients (9.7%); 10 cases corresponded to the classical form (38.5%) and 16 cases to the subclinical form (61.5%). Hyperthyroidism was found in 6/268 patients (2.2%). Normal thyroid function with positive AMA was found in 28/268 patients (10.4%). Hypothyroidism was more common in patients with mood disorders, and hyperthyroidism in patients with panic disorders. Patients with panic disorder had significant higher levels of FT4. The prevalence of positive AMA, hypothyroidism and hyperthyroidism was higher in women than men. We found a high frequency of thyroid abnormalities in a psychiatric outpatient population. These data suggests that routine evaluation of thyroid function should be considered in patients consulting for mood and panic disorders. (J. Endocrinol. Invest. 23: 102-106, 2000) (C)2000, Editrice Kurtis.
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    Weed control intensity effects on young radiata pine growth
    (2002) Kogan, M; Figueroa, R; Gilabert, H
    An experiment was conducted to quantify the effect of different weed control intensities (WCI) during the first three growing seasons in a Pinus radiata plantation. At the end of the third growing season, results showed that stem volume index of check plants was similar to that of plants that received spot applications in the first and second year. On the other hand, when plots were treated with herbicide spot application (first year) plus band or total area application (second year), the stem volume index was two and three times larger, respectively. However, if the first year WCI consisted of total area application, the second and third year treatment had less effect on yield. The largest biomass yield was obtained when plots were submitted to total area WCI during the first and second year. (C) 2002 Elsevier Science Ltd. All rights reserved.