The effect of friends on adolescent body weight

Using the first wave of the National Longitudinal Study of Adolescent Health (Add Health) survey, this paper examines the influence of peers on adolescent weight. A peer group is defined as a close circle of friends that are identified by a respondent adolescent. After controlling for school fixed effects and for a number of individual, demographic and family characteristics, we find that a higher Body Mass Index (BMI) of close friends is correlated to a higher BMI of the respondent adolescent. However, after instrumental variable analysis is performed, the effect remains significant only among women. We also found that adolescents are more responsive to the body weight of their same gender friends.     

Immunomodulatory effect of laser on whole body exposure.

All biomedical laser applications are based on the interaction of laser light with biological system. During the past decade considerable evidence has accumulated demonstrating that non-thermal exposure to laser can elicit cellular changes in the immune system. In the present study, we have analyzed the effect of laser on immune response in rats. A group of rats were exposed to 0.225 mu j/cm2 for 90 min for 3 days in specially designed fiberglass chambers. The whole body exposure of rats of He-Ne laser modulated both the humoral and cellular responses to tetanus toxoid stimulation. Plain red light used as a control for red laser light showed an appreciable degree of response as compared to the control groups, but not to the extent of the response to laser. Non-responders turned responders after exposure to laser. There was no response in unimmunized groups when exposed to laser and red light alone. The early and heightened immune response and proliferation of lymphocytes after exposure to laser is suggestive of a complex interaction at the cellular immune response level.     

The effect of meat consumption on body odor attractiveness

Axillary body odor is individually specific and potentially a rich source of information about its producer. Odor individuality partly results from genetic individuality, but the influence of ecological factors such as eating habits are another main source of odor variability. However, we know very little about how particular dietary components shape our body odor. Here we tested the effect of red meat consumption on body odor attractiveness. We used a balanced within-subject experimental design. Seventeen male odor donors were on "meat" or "nonmeat" diet for 2 weeks wearing axillary pads to collect body odor during the final 24 h of the diet. Fresh odor samples were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women not using hormonal contraceptives. We repeated the same procedure a month later with the same odor donors, each on the opposite diet than before. Results of repeated measures analysis of variance showed that the odor of donors when on the nonmeat diet was judged as significantly more attractive, more pleasant, and less intense. This suggests that red meat consumption has a negative impact on perceived body odor hedonicity.     

The effect of enkephalin dimers on body temperature in mice

Short-lasting decrease in rectal temperature in mice after intraperitoneal administration of an enkephalin dimer, the so called double-enkephalin--(Tyr-D-Ala-Gly-Phe-NH)2 (D-ENK-O)--at dose 0.1, 0.5, 1, 2.5, 5, 10 and 20 mg/kg of body weight was observed. Another double-enkephalin--Tyr-D-Ala-Gly-Phe-NH-(CH2)3-HN-Phe-Gly-D-Ala-Tyr-- fai led to produce this effect. The hypothermic effect of D-ENK-O was almost completely reduced by naloxone which suggests an involvement of opiate receptors in the D-ENK-O produced hypothermia in mice.     

The effect of maternal obesity on self-esteem and body image

Abstract stress, dissatisfaction and the feeling of inadequacy experienced as a result of the change in appearance caused by weight gain affects self -esteem and body image of pregnant women negatively. The aim of this study was to determine the relationship between maternal obesity, self-esteem and body image. The study was performed through a questionnaire in a state hospital in Trabzon, Turkey with 300 unselected pregnant women who were recruited from the delivery unit. As data collection tools, Body Image Scale (BAS) and Coopersmith Self-Esteem Scale (GIS) were used between April and May 2016. According to BMI variables, 12.3%, 57.0% and 30.7% of the pregnant women were normal, overweight and obese respectively and gained an average of 12.11?±?3.03?kg during pregnancy. Accordingly, the majority of pregnant women who participated in this study were found to be overweight and obese. While the body image of pregnant women surveyed in this study was at a high level (158.84?±?21.34), their average self-esteem was found at a moderate level (64.01?±?15.88). Based on BMI, 56.8% of the women with normal weight perceived themselves as normal, 48.0% of overweight women perceived themselves as normal and 53.3% of obese women perceived themselves as overweight. There was a positive significant relationship between participants' body image and their BMI (r?=?0.119 p?<?0.05). The pregnant women with normal BMI were more likely to feel satisfied. While 56.8% of the pregnant women at normal weight based on BMI were found to feel satisfied and 43.3% of those overweight felt satisfied, 54.3% of obese ones did not feel satisfied. A weak positive significant correlation was found between body image and self-esteem (r?=?0.172; p?=?0.003?<?0.05). As the self-esteem increases, body image increases, too. It was found that the majority of pregnant women were overweight and obese according to BMI and their average body image and self-esteem were high and medium level respectively.     

The effect of administration of estradiol and testosterone on body growth of young male rats.

The influence of estradiol and testosterone on body growth of young male Wistar rats was investigated. In the first experiment, estradiol was given to intact ad libitum fed male rats at 32, 37 and 42 days of age. Moreover, two untreated groups of animals were used: one was fed restrictedly according to the food intake of animals receiving estradiol and another was fed ad libitum. The animals were sacrificed at 47 days of age. Both untreated groups of animals achieved significantly higher body weight and length of tibia than estradiol treated animals. Also the growth of the tail of untreated animals was more intensive than that of estradiol treated animals. In the second experiment, estradiol was given to intact ad libitum fed male rats at 30, 35 and 45 days of age. Moreover, testosterone was given to a half of these animals at 45, 50 and 55 days of age. The animals were sacrificed at 60 days of age. Administration of testosterone significantly increased the growth of the tail and tibia in comparison to the animals which did not receive testosterone after estradiol administration. The results of the present study show that the inhibitory effect of estradiol on body growth of young male rats is not only the result of decreased food intake and that testosterone can improve the skeletal growth of male rats altered by previously given estradiol.     

The effect of zinc deficiency on the body composition of rats

Body composition and the levels of some plasma metabolites were measured in zinc deficient and control rats with the aim of assessing the nature of the metabolic defects resulting from zinc deficiency. Two experiments, lasting 15 and 20 d, were carried out using 52 immature rats. Zinc deficient animals were fed a diet of 1–2 mg Zn/kg. Pair fed andad libitum control rats received the same diet with 100 ppm zinc added to the drinking water. Feed intake and growth rate were measured, and the carcasses were analyzed for protein, fat, and ash. In each experiment, a group of rats were killed on d 1 to provide pretreatment values and to allow for estimates of net deposition of carcass components. Lactate, urea, and zinc were assayed in plasma, as well as zinc concentration in carcasses and liver. The main effect of zinc deficiency was to reduce feed intake and efficiency of feed conversion, resulting in a reduced proportion of carcass wat because of the reduced feed efficiency, zinc deficiencyper se resulted in an increase in the proportion of fat in the carcass. Plasma lactate concentration was unchanged, but urea concentration increased in both pair fed and zinc deficient rats relative toad libitum fed control animals. The results indicate that a defect in protein synthesis and an increase in energy expenditure, perhaps resulting from increased protein turnover, underlies the reduced growth and efficiency of feed conversion of zinc deficiency.     

The effect of body temperature on the locomotory energetics of lizards

Oxygen consumption (VO2), carbon dioxide production (VCO2), and stamina were measured in the lizard Tupinambis nigropunctatus running at sustainable and non-sustainable velocities (v) on a motor-driven treadmill. Three experimental groups were measured: field-fresh animals at body temperature (Tb) = 35 degrees C and laboratory-maintained animals at Tb = 35 and 25 degrees C. Mean preferred Tb was determined to be 35.2 degrees C. At 35 degrees C, field-fresh animals had a greater maximal oxygen consumption (VO2max corr) (4.22 vs 3.60 ml O2 g-0.76h-1) and a greater endurance. The net cost of transport (slope of VO2 on v) did not differ between the groups (= 2.60 ml O2 g-0.76)km-1). Velocity at which VO2max is attained (MAS) is 0.84 km h-1. The respiratory exchange ratio (R) exceeded 1.0 at v above MAS, indicating supplementary anaerobic metabolism. At 25 degrees C, VO2max corr was lower (2.34 ml O2 g-0.76h-1) as was endurance, MAS occurring at 0.5 km h-1. Net cost of transport was not significantly different than at 35 degrees C. The effect of Tb on locomotory costs was analyzed for this lizard and other species. It was concluded that the net cost of transport is temperature independent in all species examined and the total cost of locomotion (VO2 v-1) is temperature dependent in Tupinambis (Q10 = 1.4-2.0) and all other species examined except one. The energetic cost of locomotion [(VO2active-VO2rest)v-1], previously reported to be temperature independent in lizards, is temperature dependent in Tupinambis (Q10 = 1.3-1.6) and in two other species.2r