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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Minimal oxygen consumption and carbon dioxide production were studied in newborns without operation and with minor or major operation by means of open indirect calorimetry. (1) A postnatal increase in the mVO2 was observed in most of the full-term newborns without operation or with minor operation. (2) A postoperative increase in the mVO2, as observed in the adult, was not found in all newborns with a major operation. (3) This finding was particularly obvious in the newborn with a major abdominal operation and with a long pre- and postoperative periods of starvation. (4) The most important factor determining the postoperative decrease in the mVO2 is not the intensity of operative stress but the amount of caloric intake.
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PMID:Changes of the postoperative minimal oxygen consumption of the newborn. 96 14

Cerebral blood flow (CBF) was measured by means of Celabeled microspheres in infant (20-day-old) and adult (3-month-old) rats, anesthetised with Na-5-ethyl-5-(1-methylpropyl)2-thiobarbituric acid. Cerebral arteriovenous differences of acetoacetate, D-beta-hydroxybutyrate, glucose, lactate, and oxygen and brain DNA content were determined in other groups of similarly treated infant and adult animals fed or starved for 48 or 72 hr. The mean CBF values of 0.48+/-0.04 and 0.62+/-0.07 ml/(g X min), +/- SEM, in infant and adult animals, respectively, were not significantly different. CBF was unaffected by starvation. At any given arterial concentration the cerebral arteriovenous difference of acetoacetate was significantly higher in infant than adult rats. The same was true for D-beta-hydroxybutyrate at arterial concentrations above 1 mmol/liter. There was an approximately linear relationship between arterial concentration of acetoacetate and its cerebral arteriovenous difference in both infant and adult rats. A similar relationship was found for D-beta-hydroxybutyrate only in infant animals. In the fed state, the cerebral uptake of glucose and ketone bodies (micromoles per (mg DNA X min)) was not different in infant and adult rats. During starvation, cerebral uptake of ketone bodies expressed as micromoles per (mg DNA X min) was higher in infant than adult rats, indicating a higher rate of utilization of ketone bodies per cell in these animals. For glucose, no such difference was found in either fed or starved groups (Table 3). The average percentage of the total cerebral uptake of substrates (micromoles per min) accounted for by ketone bodies increased in both infant and adult rats during starvation. This percentage value was clearly higher in infant than adult rats during starvation. After 72 hr of starvation the values were 38.8% and 15.2% in infant and adult rats, respectively (Fig. 3). Calculated cerebral metabolic rate for oxygen (CMRO2), assuming complete oxidation of glucose and ketone bodies and expressed as micromoles per (mg DNA X min), was similar in fed and starved rats of both age groups (Table 3), indicating that ketone bodies serve as an alternative substrate for glucose during starvation. Calculated CMRO2 for glucose plus ketone bodies was similar to the measured CMRO2 in adult rats both in the fed and the starved groups. For infant rats, calculated CMRO2 for glucose plus ketone bodies was higher than measured CMRO2, indicating that in this age group a portion of substrate was used for synthesis or storage rather than for complete oxidation.
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PMID:The rate of cerebral utilization of glucose, ketone bodies, and oxygen: a comparative in vivo study of infant and adult rats. 98 May 50

Cerebral arteriovenous differences of acetoacetate, D-beta-hydroxybutyrate, glucose, lactate and oxygen and brain DNA content was measured at 20 days of age in intrauterine growth retarded (IUGR) rats and normal littermates after 48 and 72 h of starvation. Cerebral blood flow (CBF) was measured with labeled microspheres in other comparable groups of IUGR and control rats. CBF was similar in IUGR and normal littermates (0.57+/-0.09 and 0.58+/-0.10 ml/min respectively). After 48 h of starvation, arterial glucose was significantly lower in IUGR than control animals but the arterial concentrations of ketone bodies were similar. After 48 h of starvation, cerebral arteriovenous difference of beta-hydroxybutyrate was significantly higher in control than IUGR rats also when expressed per mg brain DNA as was the fractional uptake of D-beta-hydroxybutyrate. After 72 h of starvation, arterial concentrations of ketone bodies were significantly lower in IUGR rats than controls but the fractional uptake of D-beta-hydroxybutyrate was increased compared to IUGR rats starved for 48 h. The average percentage of calculated total substrate uptake (mumol/min) accounted for by ketone bodies increased in control animals from 31.1% after 48 h of starvation to 41.0% after 72 h of starvation. In IUGR rats these percentage values were 26.5 and 25.7 respectively. After 72 h of starvation the fraction of total cerebral uptake of substrates accounted for by ketone bodies was significantly higher in control that IUGR rats. As total cerebral uptake of substrates was similar between IUGR and control animals it is concluded that IUGR rats are more dependent on glucose as a substrate for the brain during starvation.
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PMID:Cerebral utilization of glucose, ketone bodies and oxygen in starving infant rats and the effect of intrauterine growth retardation. 98 34

In spite of the ill fame of useless products of metabolism that only accumulate in the blood under abnormal conditions, ketone bodies (KB) have now regained the fame as an important fuel of respiration for the brain and muscles in prolonged starvation in humans and other animals. In cold-adapted animals, ketosis has been well documented, but little is known about the physiological role of KB in cold adaptation. In this study, role of KB in nonshivering thermogenesis was investigated in warm- and cold-adapted rats with or without norepinephrine (NE) loads, a decisive lipid metabolizing hormone in cold adaptation. First, levels of blood KB and plasma free fatty acid (FFA) and FFA turnover rate were examined along with rectal temperature under continuous infusions of various doses of NE. Good dose-response relationship of rectal temperature was obtained with increasing doses of NE in cold-adapted rats, but not in warm-adapted ones. The levels of blood KB and plasma FFA in cold-adapted rats remained almost unaltered during the observation period of 30 minutes. Infusion of NE, however, greatly enhanced FFA turnover rate in cold-adapted rats as compared with controls. Next, fractional turnover rate and half-life of beta-OH-butyrate were obtained from decay curves of endogenous beta-OH-butyrate, using functionally eviscerated rats in which no KB were produced. Calculated turnover rate of KB was also found significantly increased in cold-adapted rats. Finally, the effect of NE on the production of KB was examined using the liver in situ perfusion technique of Mortimore with minor modifications. Viability of the liver preparation was guaranteed by sufficiently high rates of bile production as well as oxygen consumption. The production rate of KB in the preparation under palmitate loads of physiological medium concentration was significantly higher in cold-adapted rats than in warm-adapted controls. However, no significant effect of NE loaded simultaneously was observed in either group. Quantitative analysis shows that the turnover rate of KB in vivo essentially equals the production rate in the perfused liver when no exogenous NE is added. In contrast NE infusion the turnover rate in vivo was almost doubled that of the perfused liver. All these results indicate KB are used as an important energy source with the significancy of FFA in nonshivering thermogenesis. Moreover, it may be surmised that production of KB in vivo, particulary in the cold-adapted state, is effected by other unknown factors than NE.
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PMID:[The role of ketone bodies in nonshivering thermogenesis in cold-adapted rats (author's transl)]. 98 6

Rats fasted for 48-96h before exposure were shown to have a longer survival time at groups 33,500 ft (1 ft = 0.305 m) simulated altitude than nonfasted controls. Although both become hypothermic at 33500 ft, colonic temperatures of the fasted rats were not sufficiently lower than those of nonfasted animals to explain the difference in survival time. The injection of glucose and insulin before exposure almost completely eliminated the protection afforded by fasting, whereas glucose alone had no effect on survival. It is therefore suggested that an alteration in carbohydrate metabolism, possibly in combination with other starvation-induced changes, allowed fasted rats to survive at 33500 ft until declining body temperature reduced metabolic rate to a level compatible with oxygen supply.
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PMID:Survial of fasted rats exposed to altitude. 102 Dec 22

In order to measure local myocardial blood flow respectively, a needle-type recessed Pt electrode sealed in a thin injection needle was constructed. By means of this electrode, the myocardial blood flow in the inner and outer portions of the anterior wall of the exposed left ventricle of anesthesized dogs was studied. Under conditions, the blood flow in the inner portion (112.4 ml/100 ml/min) exceeded that in the outer portion (98.7 ml/100 ml/min). But the blood flow distribution expressed in terms of the blood flow ratio in both portions was readily varied by several pharmacological treatments, starvation, or prolongation of the experiment. Combining these observations with the results obtained in the decrease of the O2 current in the coronary occlusion test, the following possibilities seemed probable: 1) The myocardial blood flow under normal conditions was so distributed that the inner layer could be supplied with an increased blood flow and more oxygen. 2) Such a balance between the local blood flow and O2 demand can often be disturbed under various conditions, as was seen in the case of isoproterinol infusion in the present study.
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PMID:Local myocardial blood-flow measured by the use of a needle-type Pt-H2 electrode. 120

Periportal and perivenous hepatocytes possess different amounts and activities of the rate-generating enzymes of carbohydrate and oxidative energy metabolism and thus different metabolic capacities. This is the basis of the model of metabolic zonation, according to which periportal cells catalyze predominantly the oxidative catabolism of fatty and amino acids as well as glucose release and glycogen formation via gluconeogenesis, and perivenous cells carry out preferentially glucose uptake for glycogen synthesis and glycolysis coupled to liponeogenesis. The input of humoral and nervous signals into the periportal and perivenous zones is different; gradients of oxygen, substrates and products, hormones and mediators and nerve densities exist which are important not only for the short-term regulation of carbohydrate metabolism but also for the long-term regulation of zonal gene expression. The specialization of periportal and perivenous hepatocytes in carbohydrate metabolism has been well characterized. In vivo evidence is provided by the complex metabolic situation termed the 'glucose paradox' and by zonal flux differences calculated on the basis of the distribution of enzymes and metabolites. In vitro evidence is given by the different flux rates determined with classical invasive techniques, e.g. in periportal-like and perivenous-like hepatocytes in cell culture, in periportal- and perivenous-enriched hepatocyte populations and in perfused livers during orthograde and retrograde flow, as well as with noninvasive techniques using miniature oxygen electrodes, e.g. in livers perfused in either direction. Differences of opinion in the interpretation of studies with invasive and noninvasive techniques by the authors are discussed. The declining gradient in oxygen concentrations, the decreasing glucagon/insulin ratio and the different innervation could be important factors in the zonal expression of the genes of carbohydrate-metabolizing enzymes. While it is clear that the hepatocytes sense the glucagon/insulin gradients via the respective hormone receptors, it is not known how they sense different oxygen tensions; the O2 sensor may be an oxygen-binding heme protein. The zonal separation of glucose release and uptake appears to be important for the liver to operate as a 'glucostat'. Thus, zonation of carbohydrate metabolism develops gradually during the first weeks of life, in part before and in part with weaning, when (in rat and mouse) the fat- and protein-rich but carbohydrate-poor nutrition via milk is replaced by carbohydrate-rich food. Similarly, zonation of carbohydrate metabolism adapts to longer lasting alterations in the need of a 'glucostat', such as starvation, diabetes, portocaval anastomoses or partial hepatectomy.
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PMID:Hepatocyte heterogeneity in the metabolism of carbohydrates. 128 81

Several oxidative and non-oxidative stresses were applied to two transgenic strains of Drosophila melanogaster (designated P(bSOD)5 and P(bSOD)11) that express superoxide dismutase (SOD) at elevated levels, and control strains that express normal SOD levels. Transgenic strain P(bSOD)5 exposed to paraquat (1,1'-dimethyl-4,4'-bipyridinium dichloride), a redox cycling agent that generates superoxide anion when metabolized in vivo, was significantly more resistant to this xenobiotic than control flies. When test flies were subjected to 100% oxygen for 20 min each day, the mean lifespan was 3.62 days for control strain 25, but 4.35 days for both transgenic strains. The mortality curves of strains fed 1% H2O2 were similar, but the median lifespan of 72 h for controls and 64 h for transgenics suggests that the transgenic flies were slightly more sensitive to H2O2. The activity of catalase was the same for all strains. Using starvation resistance as a non-oxidative stress, flies maintained on water without any food had identical survival curves; for all strains, the median lifespan was 72 h. Throughout the lifespan, no statistically significant difference in physical activity was displayed for transgenic versus control flies. Collectively, these data suggest that the increased lifespan previously observed in SOD transgenics is specifically related to resistance to oxidative stresses.
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PMID:Stress resistance of Drosophila transgenic for bovine CuZn superoxide dismutase. 133 18

The modulating effects of ageing and malnutrition on rat myocardium were studied morphometrically with respect to the microvasculature. An increase in capillary density together with a decrease in capillary lumen cross-sectional area was noted during starvation. The important changes seen in the myocyte T-system were paralleled by a decreased diffusion distance for oxygen from the capillary lumen to the mitochondrion. The changes described in the aged rat heart point to an altered inter-relationship between parenchyma and vascularization with a lower capillary volume fraction and a greater diffusion distance from the capillary lumen to the mitochondrion; this is caused by hypertrophy of the aged myocyte. This reduction in capacity to exchange substrates is further reduced by the less developed T-system in the older myocyte.
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PMID:Effect of ageing and malnutrition on rat myocardium. II. The microvasculature. 141 86

Undernutrition may exacerbate hyperoxia-induced lung injury, a finding that may be of significance in the early clinical management of the premature human infant. Addressing this specific problem, we found that 72 h of food restriction in guinea pig pups delivered 3 days preterm increased mortality rates among pups exposed to 95% oxygen (8/18) and yet had no effect on 21% oxygen (air)-exposed pups (0/10). Reduced tolerance of hyperoxic conditions was not, however, associated with increased lung injury, assessed as pulmonary microvascular leakage. Pulmonary antioxidant enzyme activities [Cu,Zn superoxide dismutase (SOD), Mn SOD, glutathione peroxidase, and catalase] were unaltered by starvation or hyperoxia. Lung glutathione concentration was slightly decreased after food restriction, whereas hyperoxic exposure did not change either lung or bronchoalveolar lavage fluid glutathione concentrations or lung antioxidant enzyme activities. Increased susceptibility to the lethal effects of oxygen in the starved preterm guinea pig pup could not be attributed to a deficiency of pulmonary antioxidant defenses.
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PMID:Effect of food restriction on hyperoxia-induced lung injury in preterm guinea pig. 141 61


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