Flavor-postingestive consequence associations incorporate the behaviorally opposing effects of positive reinforcement and anticipated satiety: implications for interpreting two-bottle tests.

Rats consuming distinctively flavored solutions containing different numbers of calories learn to associate each flavor with the ensuing postingestive effects ("flavor-postingestive consequence learning"). The hallmark of such learning is preferential consumption of one of the flavors in two-bottle tests (both flavors presented in nutrient-identical solutions). Two experiments were conducted to characterize the relationship between the number of calories associated with flavors and subsequent preferences in two-bottle tests.

Hypertension and neuropsychological performance in men: interactive effects of age.

Potentially interactive effects of hypertension and age on the performance of neuropsychological and information processing tests were examined in 123 untreated hypertensive and 50 normotensive men. After covarying education, average alcohol consumption, trait anxiety, and depression scores, results indicated an interaction of age and hypertension. Young hypertensive men (23-40 years) scored significantly worse than young normotensive men on tests of attention/executive function and working memory; middle-aged hypertensive (41-56 years) and normotensive participants were not distinguished by any measures.

The regulator of MAT2 (ROM2) protein binds to early maturation promoters and represses PvALF-activated transcription.

The regulation of maturation (MAT)- and late embryogenesis (LEA)-specific gene expression in dicots involves factors related to ABI3, a seed-specific component of the abscisic acid signal transduction pathways from Arabidopsis. In French bean (Phaseolus vulgaris), the ABI3-like factor, PvALF, activates transcription from MAT promoters of phytohemagglutinin (DLEC2) and beta-phaseolin (PHS beta) genes. We describe the regulator of MAT2 (ROM2) as a basic leucine zipper (bZIP) DNA binding protein that recognizes motifs with symmetric (ACGT) and asymmetric (ACCT) core elements present in both MAT promoters.

Predictors of neuropsychological impairment in alcoholics: antisocial versus nonantisocial subtypes.

The role of demographic, perinatal/developmental, and acquired subject characteristics in determining neuropsychological (NP) performance was investigated in 22 alcoholics with Antisocial Personality Disorder (ASPD) and 84 non-ASPD alcoholics. Results of stepwise multiple regression analyses revealed that in ASPD subjects, poor NP performance was predicted by less education, childhood symptoms of Conduct Disorder, drinks per drinking day, and history of head injury, accounting for 80% of the explained variance (p < .0001).

An active site phenylalanine of 3-oxo-delta 5-steroid isomerase is catalytically important for proton transfer.

3-oxo-delta 5-steroid isomerase (KSI) from Pseudomonas testosteroni catalyzes the isomerization of a variety of 3-oxo-delta 5-steroids to their conjugated delta 4-isomers through the intermediate formation of a dienolate ion. This dienolate is formed by proton transfer from C-4 of the substrate to Asp-38, which then protonates the dienolate at C-6. Catalysis is enhanced by electrophilic assistance (hydrogen bonding) to the 3-oxygen by Tyr-14.

Hypertension and neuropsychological function: a lifespan perspective.

This article explores the relationship of hypertension to neuropsychological performance from a lifespan perspective. First, I examine cross-sectional and longitudinal studies of neuropsychological performance in cohorts of young to middle-aged hypertensive patients (ages 20-60); older hypertensive patients (ages 60-80+); and the young, normotensive offspring of hypertensive parents (ages 18-25). The pattern of performance deficits associated with hypertension is generally found to differ from that related to hypertension risk.

Specific disulfide formation in the oxidation of HIV-1 zinc finger protein nucleocapsid p7.

In vitro oxidation of the HIV-1 nucleocapsid protein p7 by the C-nitroso compound 3-nitrosobenzamide (NOBA) has been investigated. When reconstituted p7 was incubated with NOBA, three disulfide bonds were formed per molecule of p7, Cys 15-Cys 18, Cys 28-Cys 36, and Cys 39-Cys 49. These were identified using the proteolytic enzyme endoproteinase Lys-C and mass spectrometry.

Clinical interventions by psychologists with lesbians and gay men.

A questionnaire that assesses methods of intervention with, and attitudes toward, lesbians and gay men was completed by 139 clinical psychologists. None claimed to use aversion techniques to change sexual orientation. Eleven percent reported use of alternative methods (e.

Characterization and formation of the glutathione conjugate of clofibric acid.

The incubation of 1-O-clofibryl glucuronide (1-O-CAG), a metabolite of clofibrate, with glutathione (GSH) resulted in the appearance of a new peak when analyzed by HPLC. The use of HPLC coupled to electrospray-MS permitted the identification of the peak as S-(p-chlorophenoxy-2-methylpropanoyl)glutathione (CA-SG), formed by nucleophilic displacement of the glucuronide moiety from 1-O-CAG. Conjugate formation was enhanced 8-fold by rat liver glutathione S-transferases (GSTs).

Reaction energetics of a mutant 3-oxo-delta 5-steroid isomerase with an altered active site base (D38E).

3-Oxo-delta 5-steroid isomerase (KSI) catalyzes the isomerization of a variety of 3-oxo-delta 5-steroids to their conjugated delta 4-isomers through the formation of an intermediate dienol. Mutation of the catalytic base (Asp-38) to Glu (D38E) has been found to reduce kcat/Km for the isomerization of 5-androstene-3,-17-dione (1) to 4-androstene-3,17-dione (3) by about 300-fold (Zawrotny et al., 1991).

Evaluation of the internal equilibrium constant for 3-oxo-delta 5-steroid isomerase using the D38E and D38N mutants: the energetic basis for catalysis.

The dissociation constant (KD) for the complex of the intermediate dienol (2) and the D38N mutant of 3-oxo-delta 5-steroid isomerase (D38N.2) has been determined for the isomerization of 5-androstene-3,17-dione (1). KD for D38N.

The interaction of calmodulin with regulatory peptides of phosphorylase kinase.

The regulatory peptides Phk13 (301-327) and Phk5 (342-367) have been synthesized and their interaction with calmodulin studied. In the case of Phk13 modified forms were also synthesized in which a tryptophan group was placed at position 4 or 21, as well as a form with tryptophan at position 4 and nitrotyrosine at position 21. From tryptic digestion, circular dichroism, and radiationless energy transfer measurements, it appears that Phk13 forms an elongated complex with calmodulin in which the peptide is in a non-helical conformation, probably bent into a hairpin-shaped structure, the connecting strand of calmodulin is extended and exposed to the action of proteolytic enzymes, and the peptide makes contact with both the N- and C-terminal half-molecules of calmodulin.

Voices of fear and anxiety and sadness and depression: the effects of speech rate and loudness on fear and anxiety and sadness and depression.

Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the first study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the second study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles.

Effects of membership in bereavement support groups on adaptation to conjugal bereavement.

Examined the contribution of membership in bereavement support groups (BSGs) to bereavement adaptation in a sample of 127 widows and widowers, 37 of whom participated in BSGs, during the first 18 months of their bereavement. Both BSG members and nonmembers exhibited significant declines in depression, anger, anxiety, subjective stress, and psychotropic medication usage over the 18-month course. Multiple regression analyses revealed that neither group membership nor level of group involvement was associated with significantly greater declines in these variables, after demographic variables, initial levels of distress, and levels of perceived social support were accounted for.

Is a proton relay involved in the mechanism of 3-oxo-delta 5-steroid isomerase?

Previous reports of a UV spectral shift upon binding of the competitive inhibitor 19-nortestosterone (1) to 3-oxo-delta 5-steroid isomerase (KSI), coupled with UV resonance Raman results, have led to the conclusion that the enone moiety is polarized to a degree similar to that produced by complete protonation and that a proton relay may be involved in the enzymatic mechanism (Austin et al., 1992). These conclusions were partly based upon interpretations of the corresponding UV spectra of 1 in aqueous acid solutions.

Bereavement support groups: who joins; who does not; and why.

Compared widowed spouses who joined (n = 40) bereavement support groups (BSGs) during the first 13 months of bereavement with those who declined to join (n = 96). Controlling for gender, age, and socioeconomic status, no differences were found for perceived levels of social support, but joiners, compared with nonjoiners, reported experiencing more stressful events and scored significantly higher on measures of depression, anger, anxiety, and subjective stress. Nonjoiners and, to a lesser extent, joiners viewed those attending groups as less self-sufficient (e.

Nature of the intermediate in the 3-oxo-delta 5-steroid isomerase reaction.

The role of Tyr-14 of 3-oxo-delta 5-steroid isomerase (KSI) was probed by analysis of the spectra of 3-amino-1,3,5(10)-estratrien-17 beta-ol (4) and equilenin (5) bound to the active site of KSI. The ultraviolet spectrum of 4 bound to KSI is identical to that for 4 in neutral solution. This observation indicates that Tyr-14 does not protonate the amine group of 4 at the active site.

Energetics of 3-oxo-delta 5-steroid isomerase: source of the catalytic power of the enzyme.

Knowledge of the partitioning of the putative dienol intermediate (2) by steroid isomerase (KSI) (Hawkinson et al. 1991), in conjunction with various steady-state kinetic parameters, allows elucidation of the detailed free energy profile for the KSI-catalyzed conversion of 5-androstene-3,17-dione (1) to 4-androstene-3,17-dione (3). This free energy profile shows four kinetically significant energy barriers (substrate binding, the two chemical steps, and dissociation of product) that must be traversed upon conversion of 1 to 3.

Kinetic competence of an externally generated dienol intermediate with steroid isomerase.

The putative intermediate dienol (2) in the steroid isomerase (KSI) catalyzed conversion of 5-androstene-3,17-dione (1) to 4-androstene-3,17-dione (3) has been independently generated and tested as a substrate for KSI. At pH 7, dienol 2 is converted by KSI to a mixture of 1 (46%) and 3 (54%). The apparent second-order rate constant for reaction of 2 with KSI to produce 3 (kappa cat/Km = 2.