Genetic characterization of the zoonotic parasite Ancylostoma caninum in the central and eastern United States.

Ancylostoma caninum is the most common nematode parasite of dogs in the United States. The present study aimed to describe the molecular epidemiology of A. caninum isolates from the central and eastern states of the United States using the partial mitochondrial cytochrome oxidase (cox1) gene and to compare them with those reported globally. We isolated eggs from faecal samples of dogs and characterized each isolate based on cox1 sequences. A total of 60 samples originating from Kansas, Iowa, New York, Florida and Massachusetts were included. 25 haplotypes were identified in the United States dataset with high haplotype diversity (0.904). Sequence data were compared to sequences from other world regions available in GenBank. Global haplotype analysis demonstrated 35 haplotypes with a haplotype diversity of 0.931. Phylogenetic and network analysis provide evidence for the existence of moderate geographical structuring of A. caninum haplotypes. Our results provide an updated summary of A. caninum haplotypes and data for neutral genetic markers with utility for tracking hookworm populations. Sequences have been deposited in GenBank (ON980650-ON980674). Further studies of isolates from other regions are essential to understand the genetic diversity of this parasite.

Incidence of sex chromosome aneuploidy in a prenatal population: 27-year longitudinal study in Northern Italy.

OBJECTIVES: The availability of cell-free (cf) DNA as a prenatal screening tool affords an opportunity for non-invasive identification of sex chromosome aneuploidy (SCA). The aims of this longitudinal study were to investigate the evolution and frequency of both invasive prenatal diagnostic testing, using amniocentesis and chorionic villus sampling (CVS), and the detection of SCA in cfDNA samples from a large unselected cohort in Northern Italy. METHODS: The results of genetic testing from CVS and amniotic fluid samples received from public and private centers in Italy from 1995 to 2021 were collected. Chromosomal analysis was performed by routine Q-banding karyotype. Regression analyses and descriptive statistics were used to determine population data trends regarding the frequency of prenatal diagnostic testing and the identification of SCA, and these were compared with the changes in indication for prenatal diagnostic tests and available screening options. RESULTS: Over a period of 27 years, there were 13 939 526 recorded births and 231 227 invasive procedures were performed, resulting in the prenatal diagnosis of 933 SCAs. After the commercial introduction of cfDNA use in 2015, the frequency of invasive procedures decreased significantly (P = 0.03), while the frequency of prenatal SCA detection increased significantly (P = 0.007). Between 2016 and 2021, a high-risk cfDNA result was the indication for 31.4% of detected sex chromosome trisomies, second only to advanced maternal age. CONCLUSIONS: Our findings suggest that the inclusion of SCA in prenatal cfDNA screening tests can increase the prenatal diagnosis of affected individuals. As the benefits of early ascertainment are increasingly recognized, it is essential that healthcare providers are equipped with comprehensive and evidence-based information regarding the associated phenotypic differences and the availability of targeted effective interventions to improve neurodevelopmental and health outcomes for affected individuals. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Pharmacogenetics of obesity drug therapy.

As the prevalence and severity of obesity and its complications have risen significantly in worldwide populations, behavioral interventions alone have been inconsistent in promoting sufficient, sustained weight loss. Consequently, there has been intense interest in the development of anti-obesity medications as treatment strategies. When coupled with structured lifestyle modifications, pharmacotherapy can enhance weight loss. While less efficacious than bariatric surgery, drug therapy may be an alternative to surgery for some obese patients, and is an emerging strategy for weight maintenance. The goal of pharmacogenetics is to help identify patients who will benefit most from drug therapies while minimizing the risk of adverse effects. In this review, we summarize the pharmacogenetic literature on obesity drugs of the past (sibutramine, rimonabant), present (orlistat, lorcaserin, phentermine, topiramate), and future (buprioprion/naltrexone).

Prostacyclin receptor regulation--from transcription to trafficking.

The prostacyclin receptor (IP--International Union of Pharmacology nomenclature) is a member of the seven transmembrane G-protein coupled receptor (GPCR) superfamily. Recent concerns with selective and non-selective COX-1/COX-2 inhibition have exposed an important cardioprotective role for IP in preventing atherothrombosis. Receptor dysfunction (genetic variants) or reduced signaling (COX-2 inhibition) in high cardiovascular risk patients leads to increased cardiovascular events. These clinical observations have also been confirmed genetically by mouse knockout studies. Thus, receptor regulation is paramount in ensuring correct function in the prevention of atherothrombosis. This review summarizes recent literature on how this important receptor is regulated, from transcription to transport (to and from the membrane surface). These regulatory processes are critical in ensuring that IP receptors are adequately expressed and functional on the cell surface.

Cooling in cat visual cortex: stability of orientation selectivity despite changes in responsiveness and spike width.

Cooling is one of several reversible methods used to inactivate local regions of the brain. Here the effect of cooling was studied in the primary visual cortex (area 17) of anaesthetized and paralyzed cats. When the cortical surface temperature was cooled to about 0 degrees C, the temperature 2 mm below the surface was 20 degrees C. The lateral spread of cold was uniform over a distance of at least approximately 700 microm from the cooling loop. When the cortex was cooled the visually evoked responses to drifting sine wave gratings were strongly reduced in proportion to the cooling temperature, but the mean spontaneous activity of cells decreased only slightly. During cooling the strongest effect on the orientation tuning curve was on the peak response and the orientation bandwidth did not change, suggesting a divisive mechanism. Our results show that the cortical circuit is robust in the face of cooling and retains its essential functionality, albeit with reduced responsiveness. The width of the extracellular spike waveform measured at half height increased by 50% on average during cooling in almost all cases and recovered after re-warming. The increase in spike width was inversely correlated with the change in response amplitude to the optimal stimulus. The extracellular spike shape can thus be used as a reliable and fast method to assess whether changes in the responses of a neuron are due to direct cooling or distant effects on a source of its afferents.

Topology and dynamics of the canonical circuit of cat V1.

The neocortex is a major component of the most sophisticated and economically significant computer in existence, nevertheless the organisation and operation of its computational circuit is not yet understood. Here we make some steps toward relating anatomical structure to computational function. We use methods of quantitative neuroanatomy to estimate the cortical circuit by defining the projection matrix between the various cells types of the neocortex of the cat, and then we consider the implications of this connectivity for cortical signal processing. Our analyses show that for a reasonable choice of the ratio between excitatory and inhibitory efficacy, the overall cortical circuit lies near the border of dynamical stability. We discuss a model of co-operative competitive processing that is consistent with the observed connectivity in the superficial layers of the cortex, and consider also how the topology of the overall cortical circuit could be configured dynamically through average inhibition.

Prostacyclin, atherothrombosis, and cardiovascular disease.

Prostacyclin (PGI(2)) is a major product of COX-2 catalyzed metabolism of arachidonic acid in the endothelium. Recent studies have demonstrated that PGI(2) protects against atherothrombosis. The prostacyclin receptor knockout mice exhibit increased atherosclerosis, enhanced thrombosis, and enhanced proliferative response to carotid vascular injury with increased intima to media ratios [1-3]. Moreover, the recent withdrawal of rofecoxib (Vioxx) due to increased cardiovascular events further supports the critical role of prostacyclin in inhibiting atherothrombosis in humans. Such studies have paralleled intense chemical biology studies to develop more stable prostacyclin analogues. Indeed a number of these analogues are currently being successfully used for the treatment of pulmonary hypertension. In this review we will summarize the current literature on some principles of prostacyclin analogue development, our current understanding of the receptor, and recent developments which implicate prostacyclin in atherothrombotic protection. More than 68 million Americans suffer from cardiovascular disease, which causes more deaths, disability and economic loss than any other group of diseases. Further clinical investigations of orally stable prostacyclin analogues for treatment of cardiovascular diseases other than pulmonary hypertension may now be warranted.

Rapamycin inhibits cell motility by suppression of mTOR-mediated S6K1 and 4E-BP1 pathways.

Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), inhibits tumor cell motility. However, the underlying mechanism is poorly understood. Here, we show that rapamycin inhibited type I insulin-like growth factor (IGF-I)-stimulated motility of a panel of cell lines. Expression of a rapamycin-resistant mutant of mTOR (mTORrr) prevented rapamycin inhibition of cell motility. However, cells expressing a kinase-dead mTORrr remained sensitive to rapamycin. Downregulation of raptor or rictor by RNA interference (RNAi) decreased cell motility. However, only downregulation of raptor mimicked the effect of rapamycin, inhibiting phosphorylation of S6 kinase 1 (S6K1) and 4E-BP1. Cells infected with an adenovirus expressing constitutively active and rapamycin-resistant mutant of p70 S6K1, but not with an adenovirus expressing wild-type S6K1, or a control virus, conferred to resistance to rapamycin. Further, IGF-I failed to stimulate motility of the cells, in which S6K1 was downregulated by RNAi. Moreover, downregulation of eukaryotic initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) by RNAi-attenuated rapamycin inhibition of cell motility. In contrast, expression of constitutively active 4E-BP1 dramatically inhibited IGF-I-stimulated cell motility. The results indicate that both S6K1 and 4E-BP1 pathways, regulated by TORC1, are required for cell motility. Rapamycin inhibits IGF-I-stimulated cell motility, through suppression of both S6K1 and 4E-BP1/eIF4E-signaling pathways, as a consequence of inhibition of mTOR kinase activity.

Long-term exercise training in persons with spinal cord injury: effects on strength, arm ergometry performance and psychological well-being.

STUDY DESIGN: Randomized controlled trial of exercise training in persons with spinal cord injury. OBJECTIVE: The purpose of this study was to examine the effects of 9 months of twice-weekly exercise training on strength, arm ergometry performance, and indices of psychological well-being and quality of life. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Thirty-four men and women (aged 19-65 years) with traumatic spinal cord injury (C4-L1; ASIA A-D) of 1-24 years duration volunteered to participate, and were randomized into exercise (EX; n=21) and control (CON; n=13) groups. Twenty-three subjects (11 EX; 12 CON) successfully completed the 9-month study. Subjects were assessed for one repetition maximum (1RM) strength, arm ergometry performance, and several indices of quality of life and psychological well-being at baseline, 3, 6, and 9 months. RESULTS: At baseline, there were no significant differences between groups in age, submaximal arm ergometry performance, muscle strength, or psychological well-being. Following training, the EX group had significant increases in submaximal arm ergometry power output (81%; P<0.05), and significant increases in upper body muscle strength (19-34%; P<0.05); no significant changes occurred in CON. Participants in EX reported significantly less pain, stress and depression after training, and scored higher than CON in indices of satisfaction with physical function, level of perceived health and overall quality of life (P<0.05). Exercise adherence (per cent of prescribed sessions attended) in those subjects who completed the 9 months of training was 82.5%. CONCLUSIONS: These results demonstrate that long-term twice-weekly exercise training in this population is feasible, and results in significant gains in both physical and psychological well-being.

Does bouton morphology optimize axon length?

The total length of cortical axons could be reduced if the parent axons maintained straight trajectories and simply connected to dendritic shafts via spine-like terminaux boutons and to dendritic spines via bead-like en passant boutons. Cortical axons from cat area 17 were reconstructed from serial electron micrographs and their bouton morphology was correlated with their synaptic targets. En passant or terminaux boutons did not differ in the proportion of synapses they formed with dendritic spines and shafts, and thus, the two morphological variants of synaptic bouton do not contribute directly to optimizing axon length.

Aetiology, previous menstrual function and patterns of neuro-endocrine disturbance as prognostic indicators in hypothalamic amenorrhoea.

BACKGROUND: Hypothalamic amenorrhoea (HA) is a syndrome associated with infertility and osteopenia in reproductive-age women. METHODS: To understand better the natural history of this disorder, 28 women participated in a retrospective, questionnaire-based analysis to elucidate factors associated with spontaneous recovery. RESULTS: 54% of subjects developed HA related to an eating disorder, 21% related to stress +/- weight loss, and 25% without obvious contributing factors (idiopathic). HA associated with a clear precipitant had a better prognosis than idiopathic HA (71 versus 29% recovery; P < 0.05). Reversal of the inciting factor appeared necessary but not sufficient for recovery (83% recovery if factor reversed). Normal menarche occurred in 61% of subjects, oligomenorrhoea in 32%, and primary amenorrhoea in 7%. Oligomenorrhoea and normal menarche showed a trend toward better prognosis than primary amenorrhoea (NS). Compared with controls, 46% of HA patients had decreased frequency of LH pulses, 7% decreased amplitude, 18% decreases in both frequency and amplitude, 18% absent pulses, and 11% normal-appearing pulses. Pulse pattern at baseline did not predict recovery. CONCLUSIONS: The aetiology of HA at the time of presentation predicts subsequent recovery of menstrual function. In stress, weight loss, or eating disorder-related HA, rates of recovery exceeded 80% when precipitating factors were reversed. Idiopathic HA may represent a different disorder as recovery rates were <30%.

Point-of-purchase messages framed in terms of cost, convenience, taste, and energy improve healthful snack selection in a college foodservice setting.

OBJECTIVE: To examine the effects of a point-of-purchase (POP) intervention emphasizing various properties of healthful food items on college students' snack purchases. DESIGN: In Study 1, vegetable baskets (containing cut pieces of vegetables), fruit baskets (containing cut pieces of fruit), pretzels, and yogurt were promoted in separate POP interventions. Food sales were monitored over 2-week baseline, 4-week intervention, and 2-week follow-up periods. In Study 2, yogurt was promoted across a 2-week baseline, 12-week intervention, and 2-week follow-up periods and an intercept survey was conducted. SUBJECTS/SETTING: Approximately 2,280 university students were potentially exposed to the intervention, and 72 students responded to the intercept survey. INTERVENTION: POP messages were placed on an 11 x 17-in poster located at the cafeteria entrance, and two 4 x 2.5-in signs placed next to the targeted food item. Messages emphasized the Budget-friendly, Energizing, Sensory/taste, Time efficient/convenient (BEST) stimulus properties of food. MAIN OUTCOME MEASURES: Daily sales of the targeted food items. STATISTICAL ANALYSES PERFORMED: Analyses of variance with Tukey post hoc tests were used to compare food sales during the baseline, intervention, and follow-up periods. RESULTS: In Study 1, yogurt and pretzel sales increased during the intervention and post-intervention periods (P<.05). Interventions had no effect on fruit basket and vegetable basket sales (P>.05), but whole fruit sales increased during the fruit basket intervention and follow-up (P<.05). In Study 2, yogurt sales were significantly greater during the intervention and follow-up periods than at baseline (P<.01). APPLICATIONS/CONCLUSIONS: Using the BEST properties in POP interventions may be beneficial in promoting the consumption of healthful foods among university students, particularly when the targeted foods are priced comparably to less healthful foods.

Specific factors predict the response to pulsatile gonadotropin-releasing hormone therapy in polycystic ovarian syndrome.

Ovulation induction is particularly challenging in patients with polycystic ovarian syndrome (PCOS) and may be complicated by multifollicular development. Pulsatile GnRH stimulates monofollicular development in women with anovulatory infertility; however, ovulation rates are considerably lower in the subgroup of patients with PCOS. The aim of this retrospective study was to determine specific hormonal, metabolic, and ovarian morphological characteristics that predict an ovulatory response to pulsatile GnRH therapy in patients with PCOS. Subjects with PCOS were defined by chronic amenorrhea or oligomenorrhea and clinical and/or biochemical hyperandrogenism in the absence of an adrenal or pituitary disorder. At baseline, gonadotropin dynamics were assessed by 10-min blood sampling, insulin resistance by fasting insulin levels, ovarian morphology by transvaginal ultrasound, and androgen production by total testosterone levels. Intravenous pulsatile GnRH was then administered. During GnRH stimulation, daily blood samples were analyzed for gonadotropins, estradiol (E(2)), progesterone, inhibin B, and androgen levels, and serial ultrasounds were performed. Forty-one women with PCOS underwent a total of 144 ovulation induction cycles with pulsatile GnRH. Fifty-six percent of patients ovulated with 40% of ovulatory patients achieving pregnancy. Among the baseline characteristics, ovulatory cycles were associated with lower body mass index (P < 0.05), lower fasting insulin (P = 0.02), lower 17-hydroxyprogesterone and testosterone responses to hCG (P < 0.03) and higher FSH (P < 0.05). In the first week of pulsatile GnRH treatment, E(2) and the size of the largest follicle were higher (P < 0.03), whereas androstenedione was lower (P < 0.01) in ovulatory compared with anovulatory patients. Estradiol levels of 230 pg/mL (844 pmol/L) or more and androstenedione levels of 2.5 ng/mL (8.7 nmol/L) or less on day 4 and follicle diameter of 11 mm or more by day 7 of pulsatile GnRH treatment had positive predictive values for ovulation of 86.4%, 88.4%, and 99.6%, respectively. Ovulatory patients who conceived had lower free testosterone levels at baseline (P < 0.04). In conclusion, pulsatile GnRH is an effective and safe method of ovulation induction in a subset of patients with PCOS. Patient characteristics associated with successful ovulation in response to pulsatile GnRH include lower body mass index and fasting insulin levels, lower androgen response to hCG, and higher baseline FSH. In ovulatory patients, high free testosterone is negatively associated with pregnancy. A trial of pulsatile GnRH therapy may be useful in all PCOS patients, as E(2) and androstenedione levels on day 4 or follicle diameter on day 7 of therapy are highly predictive of the ovulatory response in this group of patients.

Serum and follicular fluid hormone levels during in vitro fertilization after short- or long-course treatment with a gonadotropin-releasing hormone agonist.

OBJECTIVE: To examine the impact of flare (short) vs. down-regulation (long) GnRH agonist (GnRH-a) on serum and follicular fluid (FF) LH and androgen concentrations in women undergoing IVF treatment cycles. DESIGN: Prospective observational study. SETTING: IVF clinic. PATIENT(S): One hundred sixteen ovulatory subjects undergoing IVF. INTERVENTION(S): Fifty-eight ovulatory patients undergoing a down-regulation regimen matched with 58 undergoing the flare regimen as part of an IVF cycle. MAIN OUTCOME MEASURE(S): Serum concentrations of LH, FSH, Progesterone (P4), Androstenedione (A), T, and E(2) on the day of hCG administration were compared between the two groups. In addition, the FF P4, 17OHP4, A, T, and E(2) levels were compared in the two groups. RESULT(S): Serum LH was significantly higher with the flare regimen (15.2 +/- 1.14 IU/L, P<.05) when compared with results with the down-regulation protocol (9.5 +/- 0.77 IU/L). In addition, FF A was significantly higher in the flare protocol (57.3 +/- 13.3 ng/mL, P<.05) compared with in the down-regulation protocol (27 +/- 2.44 ng/mL). Serum and FF P4, 17OH P4, T, and E(2) were not statistically significantly different between the two groups. CONCLUSION(S): Serum LH and FF A are significantly higher in the flare regimen in comparison with the down-regulation regimen. Circulating LH appears to play a role in determining FF A concentration.

Role of self-presentation in the health practices of a sample of Irish adolescents.

The association between self-presentational motives and health behaviors were studied in a sample of 183 Irish adolescents. Among girls, dieters and nonexercisers scored higher on measures of trait self-presentational concern than nondieters and exercisers. Self-presentational concerns were positively correlated with boys' and girls' endorsement of self-presentational motives for certain health practices.

Prevalence, phenotypic spectrum, and modes of inheritance of gonadotropin-releasing hormone receptor mutations in idiopathic hypogonadotropic hypogonadism.

Mutations in the GnRH receptor (GNRHR) have been described as a cause of reproductive failure in a subset of patients with idiopathic hypogonadotropic hypogonadism (IHH). Given the apparent rarity of these mutations, we set out to determine the frequency and distribution of GNRHR mutations in a heterogeneous population of patients with IHH who were well characterized with respect to diagnosis, phenotype, and mode of inheritance and to define their distribution within the receptor protein. One hundred and eight probands with IHH were screened for mutations in the coding sequence of GNRHR. Forty-eight of the 108 patients had a normal sense of smell, whereas the remaining 60 had anosmia or hyposmia (Kallmann syndrome). Exon segments in the GNRHR were screened for mutations using temperature gradient gel electrophoresis, and all mutations were confirmed by direct sequencing. Five unrelated probands (3 men and 2 women), all normosmic, were documented to have changes in the coding sequence of the GNRHR. Two of these probands were from a subgroup of 5 kindreds consistent with a recessive mode of inheritance, establishing a GNRHR mutation frequency of 2 of 5 (40%) in patients with normosmic, autosomal recessive IHH. The remaining 3 probands with GNRHR mutations were from a subgroup of 18 patients without evidence of familial involvement, indicating a prevalence of 3 of 18 (16.7%) in patients with sporadic IHH and a normal sense of smell. Among the five individuals bearing GNRHR mutations, a broad spectrum of phenotypes was noted, including testicular sizes in the male that varied from prepubertal to the normal adult male range. Three probands had compound heterozygous mutations, and two had homozygous mutations. Of the eight DNA sequence changes identified, four were novel: Thr(32)Ile, Cys(200)Tyr, Leu(266)Arg, and Cys(279)TYR: COS-7 cells transiently transfected with complementary DNAs encoding the human GNRHR containing each of these four novel mutations failed to respond to GnRH agonist stimulation. We conclude that 1) the spectrum of phenotypes in patients with GNRHR mutations is much broader than originally anticipated; 2) the frequency of GNRHR mutations may be more common than previously appreciated in familial cases of normosmic IHH and infrequent in sporadic cases; and 3) functional mutations of the GNRHR are distributed widely throughout the protein.

Regulation of ribosomal S6 kinase 2 by effectors of the phosphoinositide 3-kinase pathway.

Ribosomal S6 kinase (S6K1), through phosphorylation of the 40 S ribosomal protein S6 and regulation of 5'-terminal oligopyrimidine tract mRNAs, is an important regulator of cellular translational capacity. S6K1 has also been implicated in regulation of cell size. We have recently identified S6K2, a homolog of S6K1, which phosphorylates S6 in vitro and is regulated by the phosphatidylinositide 3-kinase (PI3-K) and mammalian target of rapamycin pathways in vivo. Here, we characterize S6K2 regulation by PI3-K signaling intermediates and compare its regulation to that of S6K1. We report that S6K2 is activated similarly to S6K1 by the PI3-K effectors phosphoinositide-dependent kinase 1, Cdc42, Rac, and protein kinase Czeta but that S6K2 is more sensitive to basal activation by myristoylated protein kinase Czeta than is S6K1. The C-terminal sequence of S6K2 is divergent from that of S6K1. We find that the S6K2 C terminus plays a greater role in S6K2 regulation than does the S6K1 C terminus by functioning as a potent inhibitor of activation by various agonists. Removal of the S6K2 C terminus results in an enzyme that is hypersensitive to agonist-dependent activation. These data suggest that S6K1 and S6K2 are similarly activated by PI3-K effectors but that sequences unique to S6K2 contribute to stronger inhibition of its kinase activity. Understanding the regulation of the two S6K homologs may provide insight into the physiological roles of these kinases.

Ribosomal S6 kinase 2 inhibition by a potent C-terminal repressor domain is relieved by mitogen-activated protein-extracellular signal-regulated kinase kinase-regulated phosphorylation.

Ribosomal S6 kinase 2 (S6K2) is a recently identified serine/threonine protein kinase that phosphorylates the 40 S ribosomal protein S6 in vitro. S6K2 is highly homologous to S6K1 in the core kinase and linker regulatory domains but differs from S6K1 in the N- and C-terminal regions and is differently localized primarily to the nucleus because of a C-terminal nuclear localization signal unique to S6K2. We have recently demonstrated that S6K2 is regulated similarly to S6K1 by the mammalian target of rapamycin pathway and by multiple PI3-K pathway effectors in vivo. However, deletion of the C-terminal domain of S6K2 enhances kinase activity, whereas analogous deletion of S6K1 is inhibitory. Here, we characterize the S6K2 C-terminal motifs that confer this differential regulation. We demonstrate that the inhibitory effects of the S6K2 C-terminal domain are only partly attributable to the nuclear localization signal but that three C-terminal proline-directed potential mitogen-activated protein kinase phosphorylation sites are critical mediators of this inhibitory effect. Site-specific mutation of these sites to alanine completely desensitizes S6K2 to activating inputs, whereas mutation to aspartic acid to mimic phosphorylation results in an activated enzyme which is hypersensitive to activating inputs. Pretreatment of cells with the mitogen-activated protein-extracellular signal-regulated kinase kinase (MEK) inhibitor U0126 inhibited S6K2 activation to a greater extent than S6K1. Furthermore, S6K2 mutants with C-terminal deletion or acidic phosphorylation site mutations displayed greatly reduced U0126 sensitivity. Thus, MEK-dependent inputs to C-terminal phosphorylation sites appear to be essential for relief of S6K2 inhibition but less critical for activation of S6K1. These data suggest a mechanism by which weak PI3-K agonists can regulate S6 phosphorylation and selective translation in the presence of mitogen-activated protein kinase signaling.

An Exploratory Investigation of the Relationship between Proxy Efficacy, Self-efficacy and Exercise Attendance.

The purpose of the study was to examine the relationship between perceptions of self-efficacy, proxy efficacy, and exercise class attendance of participants involved in a 10-week structured group fitness program. At week 3, 127 females completed measures of self-efficacy and proxy efficacy and their class attendance was monitored for the subsequent four weeks. Self-efficacy was assessed through measures of exercise, scheduling, and barrier self-efficacy. Proxy efficacy was assessed through a measure of fitness instructor efficacy defined as participants' confidence in their fitness instructors' communication, teaching, and motivating capabilities. Results revealed positive correlations between self-efficacy variables and proxy efficacy. Hierarchical multiple regression analyses indicated that among those who were classified as exercise initiates (n = 33), self-efficacy and proxy efficacy accounted for 34 percent of the variance in exercise class attendance with the latter variable explaining a unique 12 percent. Consistent with theorizing, these preliminary findings indicate that for instructor-led, group physical activities such as aerobics classes, proxy efficacy perceptions are related to self-efficacy and may also be an important predictor of exercise behavior.