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At least 343 records · Page 19Linked to original sources

PubMed1999

Meal feeding is more effective than early feed restriction at reducing the prevalence of leg weakness in broiler chickens.

Two trials were conducted to investigate whether manipulation of feeding pattern or early feed intake affected the prevalence of leg weakness in broiler chickens. In Trial 1, the birds were offered two, three, or four meals per day or consumed feed ad libitum. In Trial 2, a multifactorial design was used with age at start, duration of restriction, and severity of restriction as factors. The start of restrictions were at 5, 7, or 9 d, duration of restriction was 5 or 7 d, and feed was restricted to achieve 25, 50, and 75% of predicted growth during the restriction period. Ad libitum birds served as controls. Leg weakness was assessed by gait scoring (GS) and tibial dyschondroplasia (TD) by radiography. Foot burn, hock burn, angulation of the hock joint, feed consumption, and body weight gain were also assessed. The response of the birds to meal feeding was clear. Fewer meals per day was associated with less TD, less hock burn, better walking ability, lower body weight, and better feed conversion. The response of the birds to feed restriction was also clear. Earlier restriction, longer duration, and more severe level of restriction were all associated with lower prevalence of TD, better walking ability, lower body weight, and better relative growth rates and feed efficiency. However, adjusting the observations for differences in body weight removed many of the significant differences; only birds that started feed restriction earlier had less TD. From these trials, it was concluded that meal feeding can beneficially affect the prevalence of leg weakness, and that the major part of this effect is independent of changes in body weight. It was also concluded that early feed restriction reduced many aspects of leg weakness, but that these effects were mainly a result of reduced body weight. Meal feeding and early feed restriction improved feed efficiency.

Animal Feed↗

PubMed2003

The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation.

OBJECTIVES: To inform the debate over whether human sleep can be chronically reduced without consequences, we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation. DESIGN: The chronic sleep restriction experiment involved randomization to one of three sleep doses (4 h, 6 h, or 8 h time in bed per night), which were maintained for 14 consecutive days. The total sleep deprivation experiment involved 3 nights without sleep (0 h time in bed). Each study also involved 3 baseline (pre-deprivation) days and 3 recovery days. SETTING: Both experiments were conducted under standardized laboratory conditions with continuous behavioral, physiological and medical monitoring. PARTICIPANTS: A total of n = 48 healthy adults (ages 21-38) participated in the experiments. INTERVENTIONS: Noctumal sleep periods were restricted to 8 h, 6 h or 4 h per day for 14 days, or to 0 h for 3 days. All other sleep was prohibited. RESULTS: Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks. Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days, and did not significantly differentiate the 6 h and 4 h conditions. Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis--displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights. Comparison of chronic sleep restriction to total sleep deprivation showed that the latter resulted in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost. A statistical model revealed that, regardless of the mode of sleep deprivation, lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h (s.e. 0.73 h). CONCLUSIONS: Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign. Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses, but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions. This suggests that sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.

Adult↗

PubMed1995

Effect of somatotropin and feed restriction on body composition and adipose metabolism in obese Zucker rats.

The objective of the present study was to determine whether exogenous somatotropin (STH) administration in conjunction with feed restriction could alter the composition of gain in the obese rat. Five-week-old female lean and obese Zucker rats were assigned to the following treatments for 6 wk: ad libitum fed (AL), restricted (approximately 75% of AL lean), and restricted with STH (2 mg STH/day). Growth rate was decreased in restricted groups and was normalized to that of the AL lean group in restricted rats treated with STH. In lean rats, restriction decreased protein accretion. Restriction plus STH treatment decreased lipid accretion but increased protein accretion and body weight gain compared with the AL lean group. As expected, feed restriction reduced body size in obese rats, but carcass lipid was maintained at 44%, a level similar to that of the AL obese rats. Lipid accretion rate was decreased with restriction in obese rats and was further reduced, to a level similar to that of the lean group, in the obese rats that were restricted and treated with STH. Protein accretion was decreased in the restricted obese group but was normalized in those treated with STH to a level similar to that in the AL lean group. Basal rates of lipolysis in isolated adipocytes were not affected by STH. However, STH treatment normalized the responsiveness of cells from the obese rats to stimulation of lipolysis by isoproterenol. The results demonstrate that a combination of caloric restriction and STH was effective in normalizing body weight and composition of gain in the obese Zucker rat.

Adipose Tissue↗

PubMed2004

Impairments, activity limitations and participation restrictions: prevalence and associations among persons living with HIV/AIDS in British Columbia.

BACKGROUND: To measure the prevalence of and associations among impairments, activity limitations and participation restrictions in persons living with HIV in British Columbia to inform support and care programs, policy and research. METHODS: A cross-sectional population-based sample of persons living with HIV in British Columbia was obtained through an anonymous survey sent to members of the British Columbia Persons With AIDS Society. The survey addressed the experience of physical and mental impairments, and the experience and level of activity limitations and participation restrictions. Associations were measured in three ways: 1) impact of types of impairment on social restriction; 2) impact of specific limitations on social restriction; and 3) independent association of overall impairments and limitations on restriction levels. Logistic regression was used to measure associations with social restriction, while ordinal logistic regression was used to measure associations with a three-category measure of restriction level. RESULTS: The survey was returned by 762 (50.5%) of the BCPWA participants. Over ninety percent of the population experienced one or more impairments, with one-third reporting over ten. Prevalence of activity limitations and participation restrictions was 80.4% and 93.2%, respectively. The presence of social restrictions was most closely associated with mental function impairments (OR: 7.0 for impairment vs. no impairment; 95% CI: 4.7 - 10.4). All limitations were associated with social restriction. Among those with 5 vs. no limitation, 95%CI: 4.9-125.0). Among those with > 200 CD4 cells/mm3, the odds of higher restriction were increased with higher limitation (OR: 2.7 for limitation score of 1-5 vs. no limitation, 95%CI: 1.4-5.1; OR: 8.6 for limitation score > 5 vs. no limitation, 95%CI: 3.9-18.8), as well as by additional number of impairments (OR:1.2 for every additional impairment; 95% CI:1.1-1.3). CONCLUSIONS: This population-based sample of people living with HIV has been experiencing extremely high rates of impairments, activity limitations and participation restrictions. Furthermore, the complex inter-relationships identified amongst the levels reveal lessons for programming, policy and research in terms of the factors that contribute most to a higher quality of life.

Acquired Immunodeficiency Syndrome↗

PubMed2000

The effect of chronic food and water restriction on open-field behaviour and serum corticosterone levels in rats.

In operant conditioning experiments, two methods are commonly used to motivate laboratory rats to perform designated tasks. The first is restricting food so that rats are forced to lose 20% of body weight within one week, followed by maintenance at 80% of the baseline weight for the remainder of the experiment. The second is restricting access to water to 15 min in each 24 h period. These methods are effective in motivating the animals. There is, however, little information available on the effects on performance in tests of behaviour that are not related to operant conditioning. In addition, it is not clear if these commonly used methods of food and water restriction will lead to physiological stress as indicated by an elevation of serum corticosterone. Male rats were either food-restricted to reduce and maintain their weight at 80% of baseline weight, or were restricted to 15 min access to water every 24 h. Activity in the open field was significantly greater in food-restricted rats than in water-restricted or control rats, but freezing behaviour was similar in all experimental groups. Food-restricted rats had a higher mean serum corticosterone level than water-restricted and control rats 37 days after the start of the experimental period. These data suggested that chronically restricting food and maintenance of body weight at 80% of baseline body weight led to significant behavioural changes and physiological stress. In contrast, water restriction did not lead to changes in behaviour or corticosterone levels. A second experiment was conducted to compare the effects of food restriction to 80% of baseline body weight, as described above, with a less stringent protocol in which test rats were initially reduced to 80% of baseline weight, but were then maintained at 80% of an ad libitum fed control rat's weight. Serum corticosterone levels and adrenal gland weights were measured after the initial week of forced weight loss and after maintenance for 21 days. Forced loss of 20% of body weight in the first week led to significantly increased serum corticosterone levels and adrenal gland weights compared to ad libitum fed controls. Serum corticosterone levels and adrenal gland weights in rats maintained at 80% of their initial body weight for 21 days remained higher than ad libitum fed control rats. However, rats maintained at 80% of an ad libitum fed control rat's weight did not differ from control rats in serum corticosterone levels or adrenal gland weights at the end of the 21-day study period. Adjustment of the feeding regimen in this manner eliminated physiological evidence of chronic stress.

Adrenal Glands↗

PubMed1994

Right ventricular dilatation, right ventricular wall thickening, and Doppler evidence of pulmonary hypertension in patients with a pure restrictive ventilatory impairment.

The purpose of this investigation was to determine the severity of pure restrictive ventilatory impairment that results in right ventricular (RV) dilatation, increased RV wall thickness, and pulmonary hypertension. Two dimensional (2-D) echocardiography, Doppler measurements of pulmonary flow, and spirometry were performed on 26 unselected patients (17 female, 9 male) with a pure restrictive ventilatory impairment. A restrictive ventilatory impairment was defined as a forced vital capacity (FVC) < or = 80 percent predicted with a normal FEV1/FVC ratio (FEV1 = 1 s forced expiratory volume). The patients were grouped according to the severity of the restrictive ventilatory defect: mild (FVC, 65 to 80 percent predicted), moderate (FVC, 51 to 64 percent predicted), and severe (FVC < or = 50 percent predicted). An increased RV area (> 20.4 cm2) was shown in 0 of 10 (0 percent) patients with a mild impairment, 6 of 12 (50 percent) patients with moderate restriction, and 2 of 4 (50 percent) patients with severe restriction. Increased RV wall thickness (> 0.5 cm) was observed in 0 of 10 (0 percent) patients with mild restrictive impairment, 3 of 12 (25 percent) with moderate impairment, and 1 of 4 (25 percent) with severe restrictive impairment. Doppler evidence of pulmonary hypertension (ACT/ET ratio < 0.32) (ACT = acceleration time, ET = ejection time) was shown in 0 of 10 (0 percent) patients with a mild restrictive impairment, 8 of 12 (66 percent) patients with moderate restriction, and 4 of 4 (100 percent) patients with severe restriction (p < 0.01 mild vs moderate and mild vs severe). The RV area by 2-D echocardiography correlated well with the FVC percent predicted (r = 0.90, p < 0.001). The ACT/ET ratio also correlated well with the FVC percent predicted (r = 0.73, p < 0.001). In conclusion, RV enlargement and pulmonary hypertension were seen only in patients with a moderate or severe restrictive ventilatory impairment. These data may be useful in the assessment of the likelihood of subtle RV enlargement in patients with occupational pleuropulmonary disease.

Adult↗

PubMed2001

[The relationship between fall-related activity restriction and functional fitness in elderly women].

The purpose of this study was to assess the relationship between experiences of falls or fear of falling and functional fitness in the elderly. A total of 41 women, aged 66-88, who visited Fall Prevention Clinic in Tokyo Metropolitan Geriatric Hospital, underwent an interview and functional assessment. We used a questionnaire about falls, fear of falling, activity restriction, and twelve variables were used to assess functional fitness. Data were collected from June 2000 to November 2001. The subjects were classified into four subgroups: the faller group (n = 29) were subjects who had at least one or more experiences of falling accidents in the past one year; the non-faller group (n = 12) were subjects who did not have any falling accidents in the past one year; the activity restricted group (n = 12) were subjects who were restricted from going out because of fear of falling; the activity non-restricted group (n = 23) consisted of subjects who did not have any restriction concerning going out because of fear of falling. The results were: 1) Among all subjects, 85.4% had fear of falling. Among the subjects who had fear of falling. 34.3% had restricted outdoor activities due to the fear of falling. 2) Where 86.2% of the faller group responded that they had fear of falling. 83.3% of the non-faller group also responded as having fear of falling. Of the faller group, 44.0% had some restriction concerning going out because of fear of falling. In the non-faller group, 10.0% of them showed some restriction concerning going out because of fear of falling. The rate of activity restriction in the faller group was significantly higher (p < 0.05) than in the non-faller group. 3) The faller group had significantly reduced LNG with eyes open and closed, one-leg balance with eyes open, tandem walking, grip strength, and leg extension than the non-faller group. 4) The activity-restricted group exhibited significantly reduced one-leg balance with eyes open, Up & Go test, grip strength, and leg extension than the activity non-restricted group. In conclusion, lower leg strength and walking ability as well as history of falls are significant predictors of activity restriction in elderly women related to fear of falling.

Accidental Falls↗

PubMed1997

The effects of dietary restriction on insulin-like growth factor (IGF)-I and II, and IGF-binding proteins in chickens.

The effect of feed (energy/protein) restriction on circulating concentrations of insulin-like growth factor (IGF)-I and II, and IGF-binding proteins (IGFBPs) was examined in young (4-week-old) chickens. Increasing levels of feed restriction caused progressive growth retardation, as evidenced by decreased body-weight gain and reduced bone growth. Plasma concentrations of both IGF-I and IGF-II were decreased, and the degree of reduction in the plasma concentrations of these growth factors appeared to be related to the magnitude of feed restriction. A tendency for greater decreases in these growth factors appeared to be associated with greater feed restriction at the majority of time points evaluated. However, nutritional restriction had a greater effect on plasma concentrations of IGF-I than on those of IGF-II. The reductions in plasma concentrations of IGF-I were observed earlier in the experiment and at a lower degree of nutritional deprivation than for plasma concentrations of IGF-II, possibly suggesting greater sensitivity of IGF-I plasma concentrations to feed restriction. Three IGFBPs with molecular weights of 30, 36, and 40 kDa were detected by radioligand assay following separation by SDS-electrophoresis. The 30-kDa IGFBP was most affected by feed restriction with binding activity of this IGFBP increased by 2 days of feed restriction irrespective of the degree of feed deprivation. The binding activity of the 36-kDa IGFBP was increased, albeit transiently, on the second day of feed restriction. Nutritional restriction had no discernible effect on the binding activity of the 40-kDa IGFBP. Increases in the binding activity of the 30-kDa IGFBP appeared to correspond with the observed decreases in IGF-I plasma concentrations. This suggests decreased bioavailability of IGF-I, and possibly IGF-II, attributed to the formation of a complex between IGF-I and the 30-kDa IGFBP during feed restriction. The initial increase in binding activity of the 36-kDa IGFBP may suggest that this binding protein also plays a role in the regulation and availability of circulating concentrations of IGF-I and IGF-II. Although the binding activity of the 40-kDa IGFBP was unaffected by feed restriction, we can not exclude its importance in the regulation of IGF-I. The substantial binding activity of the 40-kDa IGFBP observed in this experiment suggests that it is one of the major chicken IGFBPs, and that its role in IGF-I regulation warrants further study.

Animals↗

PubMed1981

Effect of feed or water restriction on basal and TRH-stimulated growth hormone secretion in the growing turkey poult.

Both feed and water restriction of growing turkeys resulted in an increase in the basal levels of plasma growth hormone (GH). Restricted birds also showed an increased response to thyrotropin-releasing hormone (TRH) stimulation. These changes were significantly greater in feed-restricted birds than in the water-restricted birds. After return to ad lib conditions, basal plasma GH levels remained elevated above control levels in both previously restricted groups. However, the GH response to TRH stimulation returned to normal during this period. The increase in GH secretion during undernutrition is a metabolic adjustment consistent with the known role of GH in glucose, protein and fat metabolism. The elevated GH levels present after return to adequate nutrition may aid compensatory growth. Feed and water restriction were equally effective in limiting the growth of young turkey poults. Body weight gain and feed efficiency were severely affected during the first 3 weeks of restriction, but improved during the 4th week. Return to ad lib conditions resulted in compensatory growth and markedly improved feed efficiency in both restricted groups. Feed-restricted birds showed a significant increase in water consumption after 8 days of restriction. This polydipsia may result from intermittent feeding of hungary animals. Water consumption returned to normal after 1 week of ad lip feeding. Birds restricted in water consumption voluntarily limited their feed intake to a level only slightly higher than that of the feed-restricted group. When water was supplied ad lib, these birds immediately resumed normal feed consumption.

Animal Feed↗

PubMed1989

Severe feed restriction in pullets during the early growing period: performance and relationships among age, body weight, and egg weight at the onset of production.

The performance of egg type (Leghorn x Rhode Island Red) chickens that were feed restricted during the prelaying period was studied in two trials, each conducted with 300 hens. In Trial 1, treatments included 1) an ad libitum-fed control; 2) restriction for close to zero growth between 7 and 28 days of age; 3) the same restriction as (2) but continued by restriction of 50% growth up to 70 days; 4) restriction between 7 and 70 days for 50% growth; and 5) restriction for 50% growth between 7 and 98 days. In Trial 2, birds were restricted severely (close to zero growth) from 7 to 28 days of age, followed by restriction of 50% growth up to 28, 56, 84, and 112 days of age, respectively. In all cases, feed restriction resulted in a delay in the onset of egg production, leading to some increases in egg weight. Egg production rate and cumulative production were not affected, in most cases, by early feed restriction. The BW at the onset and after 20 mo of production was reduced when feed restriction was continued beyond the age of 84 days. Overall feed conversion (grams feed per egg) and feed efficiency (grams feed per gram egg mass) were not affected significantly by feed restriction, although feed efficiency (grams gain per gram feed) was improved during the prelaying period. Within each treatment, BW was positively correlated with age at onset of egg production. Egg weight was a function of both age and BW at the onset of production. The significant correlation between egg weight and BW was maintained even after a year of production.

Age Factors↗

PubMed2005

Distinct regulation of H2-M3-restricted memory T cell responses in lymph node and spleen.

CD8 T cell populations restricted by H2-M3 MHC class Ib molecules expand rapidly during primary Listeria monocytogenes infection but only minimally upon reinfection. In contrast, CD8 T cells restricted by MHC class Ia molecules undergo more delayed expansion during primary infection but rapid and robust expansion following reinfection. In this study we demonstrate that primary H2-M3-restricted CD8 T cell responses are unaffected by the frequency of naive MHC class Ia-restricted T cells during L. monocytogenes infection. The magnitude of H2-M3-restricted memory responses, in contrast, is down-modulated by increasing frequencies of MHC class Ia-restricted effector T cells following secondary systemic infection. Suppression by MHC class Ia-restricted T cells, however, is not a universal feature of MHC class Ib-restricted memory responses. Primary systemic L. monocytogenes infection followed by secondary tissue infection, for example, results in robust expansion of H2-M3-restricted memory T cells in draining lymph nodes, despite the activation of MHC class Ia-restricted memory T cell responses. Thus, whereas MHC class Ia-restricted memory T cell populations predominate in spleens following systemic reinfection, H2-M3-restricted memory T cell responses remain prominent in lymph nodes draining localized infections. Our studies demonstrate that interactions between CD8 T cell populations can differ, depending on the status of the responding T cells (naive vs memory) and the route of reinfection. These results may have important implications for prime-boost vaccination strategies.

Animals↗

PubMed1999

Calorie restriction and spontaneous hepatic tumors in C3H/He mice.

Caloric restriction started at the young adult (YA) stage and the full adult (FA) stage in mice was compared, specifically focussing on whether there would be a delay in the onset time of spontaneous hepatoma or a reduction in its frequency. Caloric restriction lengthened the life spans of both groups, the YA, and FA. Both groups showed striking reductions of spontaneous hepatomas, from 70.9 +/- 3.5% for non-restricted controls down to 35.7 +/- 5.7 and 30.4 +/- 4.0%, for mice restricted from young adult, and from full adult stages, respectively; further, the numbers of tumor-free mice in the restricted groups increased by 45.7% and 38.5%, respectively, from 11.5%, in the non-restricted control. The cumulative incidences of hepatoma in the caloric restricted groups showed a delayed and lower incidence compared with those of the non-restricted group; a parallel delay might result from a weakened activity in tumor-promotion, whereas a lower frequency, might reflect a possible reduction of target cells for hepatomata development. Both effects can be assumed to have resulted from caloric restriction. When cumulative incidences of small hepatomas were compared between the two restricted groups, restriction started at the young adult stage is assumed to have caused fewer initiation stresses, as well as to have delayed promotion, as clearly evidenced by a flatter curve of incidence with a lower total incidence. Thus, the time at which caloric restriction is started plays a critical role in its subsequent effects.

Aging↗

PubMed1990

Effect of different levels of calorie restriction on azoxymethane-induced colon carcinogenesis in male F344 rats.

Epidemiological and animal model studies indicate that increased calorie intake increases the risk for colon cancer development. Previous studies in animal models restricted the calorie intake severely, and none of these studies have investigated a dose-response effect of different levels of calorie restriction on colon carcinogenesis. The present study was designed to investigate the effect of various levels of calorie restriction on colon carcinogenesis in male F344 rats fed the low and high fat diets and the effect of these diets on the activities of colonic mucosal and tumor ornithine decarboxylase (ODC) and protein tyrosine kinase. Starting at 5 weeks of age, groups of male F344 rats were fed the low fat or high fat diets ad libitum. At 7 weeks of age, all animals except the vehicle-treated groups were given s.c. injections of azoxymethane (AOM) (15 mg/kg body weight, once weekly for 2 weeks). Four days after the second injection, groups of animals were restricted to 90, 80, or 70% of total calories consumed by the high fat ad libitum group (i.e., 10, 20, and 30% calorie restriction, respectively). In the low fat groups, animals were restricted to 80% of total calories consumed by the low fat ad libitum group (i.e., 20% restriction). Thirty-six weeks after AOM injections, all animals were necropsied and colon tumors were used for histopathology and ODC and protein tyrosine kinase analysis. In the second experiment, the protocol was the same as above except that the animals were sacrificed 5 days after the second AOM injection and colonic mucosal ODC and protein tyrosine kinase activities were assayed. The incidence and multiplicity of colon tumors were significantly inhibited in animals fed the high fat 20% calorie-restricted and high fat 30% calorie-restricted diets, as compared to those fed the high fat ad libitum diet. The regression coefficient representing the dose-response effect of different levels of calorie restriction in both high fat groups is significant. Results also indicate that AOM treatment significantly increased the colonic mucosal ODC and protein tyrosine kinase activities. This stimulation was inhibited by feeding the calorie-restricted diets. ODC and protein tyrosine kinase activities were lower in the colon tumors of animals fed the calorie-restricted diets.

Animals↗

PubMed1998

The efficacy of dietary fat vs. total energy restriction for weight loss.

OBJECTIVE: Dietary fat restriction is currently being promoted as a weight loss strategy. However, previous investigations suggest that fat restriction alone may not be more beneficial than total energy restriction for the treatment of obesity. The purpose of this project was to assess whether an energy-restricted or fat-restricted diet was more effective at promoting weight loss, improving eating behaviors, and reducing barriers to dietary adherence. RESEARCH METHODS AND PROCEDURES: Eighty individuals (15 men and 65 women) were randomized into the two treatment conditions. Subjects were 120% to 140% of ideal body weight and 25 years to 45 years old. Treatment consisted of 24 weeks of dietary fat (22 g/day to 26 g/day) or energy restriction (4,186 kJ/day to 5,023 kJ/day), including behavior modification and exercise. Body weight change, dietary intake, eating behaviors, and barriers to adherence were measured at baseline and after treatment. RESULTS: Results show that subjects in the energy-restricted condition lost over twice as much weight as those in the fat-restricted group (11.5 kg vs. 5.2 kg). Additionally, subjects in the low-energy condition had greater improvements in eating behavior scores, enhanced feelings of wellness, a greater distaste for dietary fat, and no more pronounced feelings of deprivation than did those in the fat-restricted condition. DISCUSSION: An energy-restricted diet produces greater short-term weight loss than dietary fat restriction without many of the negative consequences commonly attributed to reducing energy intake.

Behavior Therapy↗

PubMed2003

Restriction-modification system in bacteriophage MB78.

Restriction-modification system is present in bacteria to protect the cells against phage infection. Interestingly, the bacteriophage MB78, a virulent phage of Salmonella typhimurium possesses restriction-modification system. Permissive host transformed with plasmid having the genomic fragment of MB78 carrying the putative restriction-modification genes severely restrict the growth of the phage 9NA. Growth of phage MB78 is also restricted to some extent. However, the temperate phage P22 is not restricted at all. Cloning of the the putative restriction-modification genes has been done in both orientations in different vectors. The clones carrying the genes in the same orientation as that of the lacZ in pUC19 are mostly unstable. However, those are stable when cloned in opposite orientation. Viability of the transformants is strain-, orientation-, and medium-dependent. The two genes have also been cloned individually/separately. Hosts carrying only the modification gene do not restrict growth of phages while the hosts carrying only the restriction gene do. The former produces stable transformants while the latter produces very unstable transformants which were viable only upto 36 h or so. The colonies carrying modification gene were normal looking while those carrying the restriction gene were tiny, flat, and looked distressed resembling very much the clones carrying bacterial restriction-modification system. Amplification of the genes and subsequent cloning in expression vector will be carried out for characterization of the enzymes.

Base Sequence↗

PubMed2002

Toxicity of dietary restriction of fat enriched diets on cardiac tissue.

The present study examines the effects of caloric restriction in cardiac tissue evaluation markers of oxidative stress. High-fat dietary restrictions can have a long-term impact on cardiac health. Dietary restriction of control diet increased myocardial superoxide dismutase (SOD) and catalase activities. Dietary restriction of fatty acid-enriched diets increased myocardial lipoperoxide concentrations, while SOD activity was decreased in cardiac tissue of rats with dietary restriction of fatty acid-enriched diets. Dietary restriction of unsaturated fatty acid-enriched diet induced the highest lipoperoxide concentration and the lowest myocardial SOD activity. Dietary restriction of unsaturated fatty acid decreased myocardial glycogen, and increased the lactate dehydrogenase/citrate synthase ratio. Dietary restriction of fatty acid-enriched diets were more deleterious to cardiac tissue than normal ad lib.-fed diet. In conclusion, the effects of caloric restriction on myocardial oxidative stress is dependent on which nutrient is restricted. Dietary restriction of fatty acid-enriched diets is deleterious relative to ad lib.-fed chow diet.

Animals↗

PubMed2005

Contribution of different mechanisms to compensation for energy restriction in the mouse.

OBJECTIVE: Restriction of energy intake produces weight loss, but the rate of loss is seldom sustained. This is presumed to be a consequence of compensatory reductions in energy expenditure, although the exact contributions of different components to the energy budget remain uncertain. We examined the compensatory responses of mice to a 20% dietary restriction. RESEARCH METHODS AND PROCEDURES: We measured body mass, body fatness, body temperature, and the components of daily energy expenditure for 50 MF1 mice. Forty mice were then placed on a restricted diet at 80% of their ad libitum intake for 50 days. The remaining 10 mice continued to feed ad libitum. Ten days before the end of the restriction period, the same measurements were taken. RESULTS: There were no significant differences between the control and restricted groups in any parameters before restriction. During the restriction period, body mass increased in both the control and restricted groups, but at a slower rate in the restricted mice. The control group increased in both fat and fat free mass; however, although the restricted group increased fat to the same extent as the controls, fat free mass increased to a lesser extent. The contributions of the different components of the expended energy to compensate for the reduced energy intake were energy deposition, 2.2%; resting metabolic rate, 22.3%; and activity, 75.5%. DISCUSSION: Mice were able to compensate almost completely for the restricted energy intake that was achieved by altering the amount of energy required for each component of the energy budget except digestive efficiency.

Analysis of Variance↗

PubMed1977

Physical map of the bacteriophage T5 genome based on the cleavage products of the restriction endonucleases SalI, SmaI, BamI, and HpaI.

A physical map of the bacteriophage T5 genome was constructed by ordering the fragments produced by cleavage of T5 DNA with the restriction endonucleases SalI (4 fragments), SmaI (4 fragments), BamI (5 fragments), and HpaI (28 fragments). The following techniques were used to order the fragments. (i) Digestion of DNA from T5 heat-stable deletion mutants was used to identify fragments located in the deletable region. (ii) Fragments near the ends of the T5 DNA molecule were located by treating T5 DNA with lambda exonuclease before restriction endonuclease cleavage. (iii) Fragments spanning other restriction endonuclease cleavage sites were identified by combined digestion of T5 DNA with two restriction endonucleases. (iv) The general location of some fragments was determined by isolating individual restriction fragments from agarose gels and redigesting the isolated fragments with a second restriction enzyme. (v) Treatment of restriction digests with lambda exonuclease before digestion with a second restriction enzyme was used to identify fragments near, but not spanning, restriction cleavage sites. (vi) Exonucleases III treatment of T5 DNA before restriction endonuclease cleavage was used to locate fragments spanning or near the natural T5 single-chain interruptions. (vii) Analysis of the products of incomplete restriction endonuclease cleavage was used to identify adjacent fragments.

Coliphages↗