Fine-tuning timing: natural variation informs the mechanistic basis of the switch to flowering in Arabidopsis thaliana.

The evolution of diverse life history strategies has allowed Arabidopsis thaliana to adapt to worldwide locations, spanning a range of latitudinal and environmental conditions. Arabidopsis thaliana accessions are either vernalization-requiring winter annuals or rapid cyclers, with extensive natural variation in vernalization requirement and response. Genetic and molecular analysis of this variation has enhanced our understanding of the mechanisms involved in life history determination, with translation to both natural and crop systems in the Brassicaceae and beyond.

Clinical safety assessment of oral higenamine supplementation in healthy, young men.

OBJECTIVE: Higenamine, an herbal agent also known as norcoclaurine, is thought to stimulate ß-androgenic receptors and possess lipolytic activity. It is currently making its way into the dietary supplement market. To our knowledge, no studies have been conducted to determine the safety profile of oral higenamine when used alone and in conjunction with other commonly used lipolytic agents. METHODS: Forty-eight men were assigned to ingest either a placebo, higenamine, caffeine, or higenamine + caffeine + yohimbe bark extract daily for a period of 8 weeks. Before and after 4 and 8 weeks of supplementation, the following variables were measured: resting respiratory rate, heart rate, blood pressure, urinalysis, complete blood count, metabolic panel, liver enzyme activity, and lipid panel. RESULTS: No interaction effects were noted for any variable (p > 0.05), with no changes of statistical significance occurring across time for any of the four conditions (p > 0.05). CONCLUSION: This is the first study to determine the safety profile of oral higenamine intake in human subjects. Our data indicate that 8 weeks of daily higenamine supplementation, either alone or in conjunction with caffeine and yohimbe bark extract, does not result in a statistically significant change in any of the measured outcome variables. Additional studies, inclusive of a larger sample size, are needed to extend these initial findings.

Natural variation in GL1 and its effects on trichome density in Arabidopsis thaliana.

The ultimate understanding of how biological diversity arises, is maintained, and lost depends on identifying the genes responsible. Although a good deal has been discovered about gene function over the past few decades, far less is understood about gene effects, that is, how natural variation in a gene contributes to natural variation in phenotypes. Trichome density in Arabidopsis thaliana is an ideal trait for studies of natural molecular and phenotypic variation, as trichome initiation is genetically well-characterized and trichome density is highly variable in and among natural populations. Here, we show that variation at GLABRA1 (GL1), an R2R3 MYB transcription factor gene, which has a role in trichome initiation, has qualitative and likely quantitative effects on trichome density in natural accessions of A. thaliana. Specifically, we characterize four independent loss-of-function alleles for GL1, each of which yields a glabrous phenotype. Further, we find that a pattern of common polymorphisms confined to the GL1 locus is associated with quantitative variation for trichome density. While mutations resulting in a glabrous phenotype are primarily coding changes, the pattern resulting in quantitative variation spans both coding and regulatory regions. These data show that GL1 is an important source of trichome density variation within A. thaliana and, along with recent reports, suggest that the TTG1 epidermal cell fate pathway generally may be the key molecular genetic source of natural trichome density variation and an important model for the study of molecular evolution.

Plasma protein carbonyl response to increasing exercise duration in aerobically trained men and women.

The purpose of this study was to determine the effect of aerobic exercise duration on plasma protein carbonyl concentrations, a marker of protein oxidation, in aerobically trained men and women. Eight men (age: 27 +/- 4 years, VO (2peak): 4.09 +/- 0.26 L x min (-1); mean +/- SD) and 7 women (age: 27 +/- 6 years, VO (2peak): 2.33 +/- 0.24 L x min (-1)) exercised on an electrically-braked cycle ergometer at 70 % VO (2peak) for 30, 60 or 120 minutes on three separate days. Plasma samples collected before and immediately, 30- and 60-minutes post-exercise were analyzed for protein carbonyls. Mean oxygen uptake was greater for men in all conditions (2.75 +/- 0.03 L x min (-1); 38 +/- 0.43 ml x kg (-1) x min (-1)) compared to women (1.57 +/- 0.03 L x min (-1); 24.1 +/- 0.47 ml x kg (-1) x min (-1)). Total work performed during the exercise sessions was also greater for men than for women during the 30 (368 +/- 11 versus 223 +/- 7 kJ), 60 (697 +/- 17 versus 423 +/- 18 kJ), and 120-minute conditions (1173 +/- 44 versus 726 +/- 28 kJ) (Mean +/- SEM). Although these comparisons were significant (p < 0.0001), sex differences in total work performed and mean VO (2) did not result in sex differences in protein carbonyls. However, a condition by time interaction was observed with greater post-exercise values following the 120-minute condition compared to both the 30- and 60-minute conditions. Protein carbonyl concentration was greatest immediately post-exercise for both men and women and generally declined in a linear trend through one hour of recovery. These data suggest that protein carbonyl concentration is elevated by cycling exercise performed at 70 % VO (2peak), is greater following longer duration rides, begins to recover within one hour following exercise, and is not different between men and women.

Effects of exercise and weight loss on mental stress-induced cardiovascular responses in individuals with high blood pressure.

The purpose of this study was to determine the effects of exercise and weight loss on cardiovascular responses during mental stress in mildly to moderately overweight patients with elevated blood pressure. Ninety-nine men and women with high normal or unmedicated stage 1 to stage 2 hypertension (systolic blood pressure 130 to 179 mm Hg, diastolic blood pressure 85 to 109 mm Hg) underwent a battery of mental stress tests, including simulated public speaking, anger recall interview, mirror trace, and cold pressor, before and after a 6-month treatment program. Subjects were randomly assigned to 1 of 3 treatments: (1) aerobic exercise, (2) weight management combining aerobic exercise with a behavioral weight loss program, or (3) waiting list control group. After 6 months, compared with control subjects, participants in both active treatment groups had lower levels of systolic blood pressure, diastolic blood pressure, total peripheral resistance, and heart rate at rest and during mental stress. Compared with subjects in the control group, subjects in the exercise and weight management groups also had greater resting stroke volume and cardiac output. Diastolic blood pressure was lower for the weight management group than for the exercise-only group during all mental stress tasks. These results demonstrate that exercise, particularly when combined with a weight loss program, can lower both resting and stress-induced blood pressure levels and produce a favorable hemodynamic pattern resembling that targeted for antihypertensive therapy.

Effects of meal form and composition on plasma testosterone, cortisol, and insulin following resistance exercise.

The purpose of this study was to examine the effects of postexercise feeding on plasma levels of insulin, testosterone, cortisol, and testosterone:cortisol (T:C). Ten experienced, resistance trained males (20.7 +/- 0.95 years) were given whole food (WF: protein 38 g; carbohydrate 70 g; fat 7 g), a supplemental drink (SD; isocaloric and isonitrogenous to WF), an isocaloric carbohydrate beverage (C), or a placebo beverage (P) immediately, 2 and 4 hours after a standardized weight training protocol on 4 days, each separated by 1 week, in a repeated measures design. Subjects also received a standardized meal at 7 and 12 hours postexercise. Insulin, testosterone, and cortisol were measured pre-exercise and during 24 hours of recovery (at 0.5, 2.5, 4.5, 8, and 24 hours) using venous blood samples. Significant (condition 3 time) interactions were found for insulin, testosterone, and T:C, but not for cortisol (p <. 05). The SD yielded a greater response for insulin than all other conditions. Conversely, P demonstrated the greatest values for testosterone and T:C at 2.5 and 4.5 hours postexercise. Cortisol did not vary between conditions and there were no condition effects for insulin, testosterone, cortisol, and T:C at 8 or 24 hours. In conclusion, the efficacy of postexercise feeding for optimizing T:C and muscle growth is unclear; however, consumption of SD appears to maximize circulating insulin for several hours following resistance exercise.

The inability of physicians to predict the outcome of in-hospital resuscitation.

OBJECTIVE: To measure the accuracy, reliability, and discrimination of physicians' predictions of the outcome of in-hospital cardiopulmonary resuscitation (CPR), using a large series of detailed clinical vignettes of patients with known outcomes. DESIGN: Faculty and resident physicians at three university-affiliated generalist training programs were given one-page summaries of admission data for patients who later underwent in-hospital CPR. These summaries included all pre-arrest variables known to be related to the outcome of CPR. Physicians were asked to estimate the probability that patients would survive the resuscitation long enough to be stabilized, and the probability of survival to discharge. SETTING: Patient cases were derived from a consecutive series of patients undergoing CPR at two urban teaching hospitals in Detroit, Michigan. PARTICIPANTS: Faculty members and residents at a university-based department of internal medicine and two university-based departments of family medicine were surveyed. INTERVENTIONS: Accuracy of the physician predictions was assessed by comparing the mean predicted probability of survival with the percentage of patients who actually survived. The reliability of probability estimates of survival was evaluated by assessing the numerical proximity of the estimates to the actual outcome of the resuscitative effort. The ability to discriminate between survivors and nonsurvivors was measured by comparing the mean predicted probability of survival for those patients who survived CPR with that for those who did not, and by stratifying physician predictions and measuring the area under a receiver operating characteristic (ROC) curve. MEASUREMENTS AND MAIN RESULTS. Physicians (n = 51) made a total of 713 estimates, and showed poor accuracy, reliability, and discrimination in predicting the outcome of in-hospital CPR. The mean predicted probability of survival to discharge did not differ between patients who actually survived to discharge and those who did not (29.5% vs 26.4%, z = 0.35, p = .73). Similarly, the mean predicted probabilities of surviving resuscitation were the same for patients who actually survived long enough to be stabilized and those who did not (37.8% vs 39.9%, z = 0.55, p = .58). Accounting for type of physician and institution by analysis of variance did not change this finding. The area under the ROC curve for the prediction of arrest survival was 0.476, which is not significantly different from 0.5, and is consistent with an ability to discriminate between survivors and nonsurvivors that is no better than random choice. CONCLUSIONS: Physicians were no better at identifying patients who would survive resuscitation than would be expected by chance alone. Further work is needed to establish which variables are used by physicians in the decision-making process, and to design educational interventions that will make physicians more accurate prognosticators.

A technique for long-term collection of uterine contents from mares.

A technique for collection of uterine contents from mares is described: it uses a purse-string suture of the cervix to retain a collecting device. Its use during collection of uterine fluids in various experiments is evaluated. The procedure was satisfactory for at least eight-hour collection periods.

Susceptibility of various poultry species to dietary aflatoxin.

1. The relative sensitivities of broiler chicks, White Leghorn chicks, quail chicks, goslings and turkey poults to increasing dietary contents of aflatoxin from 1 to 21 d of age were determined. Aflatoxin was included in the diets at three concentrations (0.7, 1.4 and 2.1 mg aflatoxin B1 equivalents/kg). 2. Data were analysed for species differences in food consumption, body weight, food utilisation, mortality and liver pathology. 3. There were no significant effects of aflatoxin in broiler and Leghorn chicks. Aflatoxin at 0.7 mg/kg decreased the body weight of turkey poults but tended to increase the growth rate of goslings. At 1.4 mg aflatoxin/kg food consumption, body weight and weight gain of goslings were adversely affected. 4. Liver damage occurred in goslings and quail chicks at all inclusions of aflatoxin and was extensive at 2.1 mg/kg. 5. Poults and goslings appeared to be the most sensitive, quail were intermediate and domestic chicks were most resistant.

Occlusal characteristics and tooth mobility in periodontally healthy young males classified orthodontically.

Three groups of periodontally healthy young males classified as to orthodontic status by the Handicapping Labio-Lingual Deviations Index were evaluated for various occlusal characteristics. A much larger proportion (95%) of the orthodontically normal subjects (Group I) had an Angle Class I type of occlusion than the Group II subjects requiring orthodontic care (60.5%), or the Group III subjects who had received orthodontic care (63.4%). The percentages of subjects with a "cuspid-protected" type of occlusion were larger in the orthodontically normal and orthodontically treated groups than in the group requiring orthodontic care. Anterior displacement of the mandible in closing from centric relation to the intercuspal position was found in the majority of subjects in each group. Displacement of more than 2 mm was most common in the subjects requiring orthodontic care. Only 1 of the 41 orthodontically treated subjects reported that his occlusion had been adjusted by grinding after tooth movement. There were no statistically significant differences in mean tooth mobility values between the orthodontically normal and orthodontically treated subjects. The lateral incisor tooth had a significantly lower mean mobility value in subjects whose orthodontic care included removal of the first premolar than in subjects treated without removal of the first premolar. Wear facets were common in all three groups. Based on the findings, one can conclude that orthodontic therapy was only partially successful in obtaining the objectives described as part of an ideal result. It should be noted, however, that the status of the dentition and occlusion prior to orthodontic treatment could not be determined for more than a few subjects.

Interproximal contact and marginal ridge relationships in periodontally healthy young males classified as to orthodontic status.

Three groups of periodontally healthy young males, classified as to orthodontic status, were evaluated for proximal contact and marginal ridge relationships in the maxillary left quadrant. The majority of anterior teeth did not have satisfactory proximal contacts on both the mesial and distal aspects. Open or defective proximal contact relationships were common in all three orthodontic groupings. In posterior areas, the orthodontically treated group had the highest percentage of open contacts. The orthodontically treated group had a significantly higher percentage of even marginal ridges in the teeth that are customarily banded.