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PubMed1979

[Lysine requirement of fattening boars in respect to their performance. 1. Influence of the consumption of energy and amino acids on the fattening performance].

With a total number of 157 boars 9 feeding variants with different levels of energy and amino acids were checked. The weight increase per fattening day and the energy and lysine expenditure per kg live weight increase were determined. The insufficient supply with lysine had negative effects on the live weight increase and the energy expenditure during the whole fattening period. Between the variantes with a high supply with amino acids (120%) and the supply according to standard (100%) no significant differences concerning the live weight increase could be ascertained up to 90 kg live weight. Between 90 and 120 kg live weight the animals in the variant with medium energy level and 120% lysine supply achieved significantly higher increases than those in the standard variant. Up to 90 kg live weight the energy expenditure for all groups amounted to 2,08 kEFs (energetic feed units for pigs) per kg live weight increase. The most suitable results were achieved by the animals which received the variants rich in energy (1,760 resp. 1,770 kEFs per kg live weight increase). Above the 90 kg live weight limit the energy expenditure rose considerably, remained however under 2,000 kEFs per kg live weight increase for the boars of the variant with medium energy level and 120% lysine supply as well as for the variant rich in energy and 100% lysine supply. The lysine expenditure in the first variant amounted to 25.1 g per kg live weight increase and for the variant rich in energy to 20.6 g lysine per kEFs.

Amino Acids↗
PubMed1979

Nutrient intake, adiposity, and diabetes.

To study the role of nutritional factors in the genesis of diabetes, estimations of blood sugar concentration, food intake, and adiposity (as body mass index; BMI) were carried out on three normal population samples--namely, 961 employees of Beecham Ltd, 1005 employees of the Greater London Council, and 1488 middle-aged male civil servants (Whitehall study). Blood sugar concentrations and indices of glucose tolerance correlated positively with the degree of adiposity but tended to be negatively correlated with total food energy intake and its component nutrients (total carbohydrate, sucrose, and fat). This inverse trend was largely accounted for by highly significant inverse correlations between food energy intake and adiposity, a relation found in both sexes and in all three population samples and which extended across the whole range of nutrient intake and BMI. These findings suggest that greater degrees of adiposity are associated with lower than average food energy intakes and hence lower total energy expenditures. The association of increased adiposity with low food energy consumption may indicate an underlying "low energy throughput" state, and it may be the mechanisms of this, as well as the obesity, that are responsible for disease.

Adipose Tissue↗
PubMed1978

The effect of dietary carbohydrate:fat ratio on energy intake by adult women.

The effect of the dietary carbohydrate:fat (C:F) ratio on the spontaneous energy intake by healthy adults was investigated by comparing a high-carbohydrate diet (fat 24%, carbohydrate 58%, protein 18% of energy) and a high-fat diet (fat 47%, carbohydrate 35%, protein 18% of energy) in a 2 X 2 week cross-over design. Subjects were 22 healthy nuns in a Trappist convent with very regular activities. The diets consisted of combinations of liquid formula (75%) and standardized snacks (25%). The difference in C:F ratio was concealed: energy density, taste and appearance were similar. Energy consumption was recorded continuously. The mean daily energy intakes remained constant: 8276 kJ (1978 kcal). The difference in mean daily energy intake between diets was 73 kJ +/- 180 (SEM). Small changes in body weight were observed, but these are argued not to indicate definitive effects. It is concluded that changing the C:F ratio within commonly occurring ranges does not influence the spontaneous energy intake of healthy adults. The composition of the dietary fat was kept constant. Under practical conditions a change in the C:F ratio will also induce a change in the fatty acid composition of the diet, which might affect the energy intake regulation. Other experiments are required to see whether the C:F ratio can affect body composition or other physiological parameters in the long run.

Body Composition↗
PubMed2025

New insights into multistability and complex resonances driven by subthreshold periodic signals in a neuronal model.

Understanding how neurons respond to weak external signals is crucial for accurate signal transmission and processing in both individual nerve cells and interconnected neuronal networks. One mechanism for the detection of these responses is through resonances. In this paper, we numerically investigate the firing patterns induced in a silent Huber-Braun neuron by a sinusoidal external force. We observe complex resonance patterns, including a sequence of frequency-locking exhibited in a Devil's Staircase structure. Furthermore, we also explore the emergence of multistability induced by the nonlinear resonance. This multistability manifests as the coexistence of three attractors, such as periodic spiking, chaotic spiking, and subthreshold oscillations. The dynamical behaviors are comprehensively analyzed using time series, bifurcation diagrams, phase portraits, and the basin of attraction. In addition, we compute the maximum Lyapunov exponent to verify chaotic regimes, and estimate the fractal dimension of basin boundaries using the uncertainty exponent. We also analyze the energy consumption of resonance-induced firing patterns and coexisting attractors. The results presented in this paper have important implications for understanding the detection of subthreshold signals and the encoding of stimulus information within a neuron's firing patterns.

Basins of attraction↗
PubMed1977

Respiratory muscle fatigue: a cause of respiratory failure?

1. The question whether respiratory muscle fatigue ever causes respiratory failure is over 40 years old, but we still have no definitive answer to this question. Skeletal muscle fatigue occurs when the rate of energy consumption of the muscle is greater than the energy supplied, so that energy stores are utilized and eventually become depleted. 2. Five factors which are important in the development of muscle fatigue (a, the tension developed by the muscle; b, the maximum tension the muscle can develop; c, the energy stored within the muscle; d, the energy supplied to the muscle; e, the efficiency of the muscle). These can be affected in many diseases, so disposing to fatigue, thus respiratory muscle fatigue is likely to be a common occurrence. 3. Respiratory muscle fatigue can in principle easily be diagnosed at the bedside by application of a simple electromyographic technique used to detect fatigue in other skeletal muscles.

Electromyography↗
PubMed1978

[Preventive measures in the management of the environment].

The natural and the man made environment influence the wellbeing and the health of the population. The management of the environments aims at the improvement of health and the disposal of health risks. The physical and psycho-social environment has to be taken into consideration, especially in connection with work, housing, energy consumption and spare time activities. Laws concerning environmental protection and energy supply could contribute to improvement of the environment.

Conservation of Natural Resources↗
PubMed1979

Aerobic and anaerobic metabolism of the crystalline lens of a poikilotherm; the toad Bufo marinus.

1. The O2 consumption and lactic acid production of the lens of the toad Bufo marinus was measured under various conditions. The energy consumption was very low compared to other amphibian tissues and about 20% of that previously described in the rat lens. About 80% was derived from oxidative metabolism, which is the converse of that seen in mammals. 2. Cyanide abolished O2 consumption and increased lactate production 20-30 times ("Pasteur effect"). 3. Under aerobic conditions about 40% of the energy requirements of the lens are related to the presence of Na in the bathing-media but this was not seen in the presence of CN. 4. Oxidative metabolism was predominant in the outer cortical regions of the lens while glycolysis persisted even in the central nucleus. The energetic requirements of this region were, however, only about 10% of those in the intact lens. 5. Lactate readily leaves the lens and passes into its bathing fluids, and at high rates of glycolysis this occurs more readily across the posterior surface. 6. The results are discussed in relation to the unique physiological needs, structure and situation of the lens.

Aerobiosis↗
PubMed1978

[Definition of the organell concept].

Since the essential cytological functions are endergonic processes, the organelle cannot be defind without considering the necessary energy transfer. Therefore, a sensible definition may read: The Organelle is a cytoplasmatic structure capable of funtional energy consumption (Frey-Wyssling 1977).

Energy Metabolism↗
PubMed1975

Malnutrition studies in Macaca mulatta. IV. Energy and protein consumption during growth failure and "catch-up" growth.

Infant rhesus monkeys were fed either a control, dilute or low protein diet from 1 to 7 months of age, and the control diet from age 7 to 12 months. All diets were fed ad libitum. Curves were fitted for energy and protein consumption and for growth in weight, length and head circumference. Both experimental groups developed increasing deficits of energy and protein consumption during the undernutrition experiment. With nutritional rehabilitation, the animals previously fed the dilute diet immediately increased their consumption of energy and protein to levels appropriate for age. Those previously fed the low protein diet showed an increased nutrient uptake, but one more appropriate for size peers. Reduced growth velocity occurred with both experimental diets. "Catch-up" growth, and growth velocity per unit diet energy and protein was most obvious for body weight, but recovery from growth deficits was most complete for growth in head circumference. Nutrient deficits accumulated by animals fed the dilute diet were not recovered during catch-up growth; catch-up growth occurred in animals previously fed the low protein diet even though cumulative nutrient deficits were increasing.

Animals↗
PubMed1977

[Studies on the relationship of maturity to the tolerance of ischemia].

In newborn rabbits during asphyxia caused by ligature of the trachea circulation was maintained 2-3 times as long as in adult rabbits because in contrast to the adults myocardial energy loss in asphyxia is rather low caused by a small energy consumption for circulatory work. In the cerebral cortex of newborn rabbits glycolysis is able to meet a good part of energy demand, with the energetic situation predominantly depending on glucose supply by maintenance of circulation. Thus in addition sufficient blood glucose levels deliberated from glycogen stores in liver and lung are an important factor for the central nervous revivability. Kidney and skeletal muscle tolerate anaerobic periods for rather long time because of their high glycogen stores and low metabolic activity but do not contribute to glucose supply of other tissues.

Animals↗
PubMed1979

Total mechanical energy of a ventricle model and cardiac oxygen consumption.

Mechanical energy (ENG) required by a time-varying elastance model of the ventricle was compared with oxygen consumption per beat (VO2) of the canine left ventricle contracting under a variety of loading conditions. ENG needed for this model to increase its elastance during systole is shown to be equal to the sum of the potential energy built in the elastance during systole plus the external mechanical stroke work. This ENG is equivalent to the area (PVA) bounded by the end-systolic and end-diastolic P-V curves and the systolic limb of the P-V loop trajectory in the P-V plane. There was a high correlation (r = 0.89) between VO2s documented in the literature and PVAs assessed by the author from the accompanying P-V data from both isovolumic and ejecting contractions in 11 hearts. A linear regression analysis yielded an empirical equation: VO2 (ml O2/beat) = a . PVA (mmHg . ml/beat) + b, where a = 1.37 X 10(-5) and b = 0.027, which can be used to predict VO2 from PVA. A preliminary experimental study in my laboratory confirmed the validity of this empirical equation.

Elasticity↗
PubMed1975

Energetics of abiogenic chemical systems.

After recalling the energy consumption necessary to produce the main categories of biochemicals from the equilibrium state of an hydrogenated atmosphere, the primary processes by which energy can be absorbed in a mixture of methane and ammonia in the presence of aqueous solutions are defined. From the very first excitations, unsaturated products are formed. In fact, this formation of atmospheric precursors is the primordial state of a photochemically induced redox dismutation. The evolution of solutions obtained from the dissolution of these atmospheric precursors in aqueous media is described from experimental data and analysed on energetic grounds. The relaxation of energy accumulated in such solutions involves non enzymic archetypes of the main categories of metabolic processes; in particular some unsaturated atmospheric precursors must be looked upon as primordial representatives of biochemical dehydrating agents. Absorption of light energy in the solutions obtained from the evolution of precursors happens near the visible range and should govern their further evolution. In fact, biochemicals which were previously detected as products of model experiments are not present in these solutions. They were probably obtained during analytical procedures from products of the evolution of atmospheric precursors which are unstable against decreases of pH. Cyclic autocatalytic effects must be involved in the further evolution of the models of the first aqueous solutions. Their possible role in the appearance of optical dissymmetry is emphasized on theoretical grounds.

Amino Acids↗
PubMed1976

Effects of a low-protein diet during pregnancy of the rhesus monkey I. Reproductive efficiency.

Pregnant rhesus monkeys were fed a control diet of modified cow's milk or an experimental diet containing only 25% as much as protein but made isocaloric with supplemental lactose. The ad libitum consumption of the control and experimental diets provided about 2 and 0.5 g of protein/kg of body weight per day, respectively. Total volume and energy consumption of control and experimental animals were generally comparable per kilogram of body weight, with groups showing a reduction in intake of about 20% during the latter part of pregnancy. Control females gained an average of 1.3 kg during pregnancy compared to 0.02 kg by the monkeys fed the low-protein diet. One of 15 infants born to control animals died shortly after birth; eight of 16 pregnancies in animals on the low-protein diet resulted in maternal and fetal death, stillbirth, or death in the newborn period. The birth weight of full term infants from mothers fed the low-protein diet was depressed by about 15%, and fetal linear growth was affected very little, but fetal and perinatal survival were low. We conclude that growth measurements of the newborn infants were relatively insensitive indices of the severity of the maternal nutritional deficiency and of the prognosis for the infant.

Abortion, Spontaneous↗
PubMed1977

Sodium chloride stimulated respiration of Anacystis nidulans.

With certain salts a stimulation of respiration of the blue-green alga Anacystis nidulans was found in the dark. The stimulation was observed only at high concentrations (10(-2)M--10(-1)M). NaCl or LiCl are the most effective salts and on addition the increase of the respiration is about 2.5fold. Li is assumed to function as a substitute for Na. Potassium salts, except KCl, are ineffective. The order for the effectiveness is: NaCl greater than NaNO3, Na2SO4 greater than KCl greater than KNO3, K2SO4 (=zero). Accordingly, the cation Na+, and to a less degree the anion Cl- are responsible for the stimulatory effect. K, which is ineffective, is passively accumulated by Anacystis according to the membrane potential. Na is actively extruded. At 0.1 M external NaCl, the passive influx of Na is high, but even then it is balanced by an active efflux. This increases the energy consumption of the cells and leads to a stimulated respiration. With DCCD (N,N'-dicyclohexylcarbodiimide) or NEM (N-ethylmaleimide), the Na efflux is inhibited, simultaneously the stimulation of respiration is abolished and the passive influx of Na becomes detectable. At 0.1 M NaCl, the passive influx of Na measured in presence of DCCD is 5 x 10(-6) moles Na/min and ml packed cells. In absence of DCCD on addition of 0.1 M NaCl the extra oxygen consumption is 2 x 10(-6) moles O2/min and ml cells. This may prove that the stimulation of respiration is mainly caused by the active Na extrusion.

Chlorides↗
PubMed1978

Phosphorus nuclear magnetic resonance studies of phosphorus metabolites in frog muscle.

31P-nuclear magnetic resonance was applied to living muscles of bullfrogs, and the time courses of metabolic changes of ATP, creatine phosphate, inorganic phosphate, and sugar phosphates were studied under anaerobic and aerobic conditions. A decrease in creatine phosphate was observed in the resting muscle under anaerobic conditions with a concomitant decrease in the intracellular pH, while the ATP level remained constant. With the use of 2,4-dinitro-1-fluorobenzene and iodoacetic acid, ATP disappeared quickly. When the resting muscle was perfused with oxygen-saturated glucose-Ringer's solution, the amount of creatine phosphate increased gradually. These findings indicate that anaerobic glycolysis is insufficient for even the resting energy consumption whereas oxidative phosphorylation is sufficient. The effects of tetanic stimulation on living muscles were also studied. When glycolysis and oxidative phosphorylation were suppressed, the intracellular energy store was depleted by the tetanic contraction. Anaerobic glycolysis produced rapid recovery of the energy store level, although it was insufficient to reach the initial level. Aerobic oxidative phosphorylation produced sufficient energy to reach the initial level, and this level was never exceeded. This finding suggests the existence of a regulatory mechanism for the energy store level.

Adenosine Triphosphate↗
PubMed2026

Acute Stevia Consumption does not Alter Endocrine Responses in Individuals with Normal Weight, Overweight, and Type 2 Diabetes Mellitus.

BACKGROUND: Stevia is a plant-based non-nutritive sweetener. Acute effects of stevia ingestion on glycemia and hormonal responses have not been fully investigated. OBJECTIVE: This objective of this study was to evaluate the acute effects of beverages containing stevia alone and in combination with glucose on glycemic, hormonal, and appetite responses. METHODS: This study evaluated three cohorts of n=23 individuals with either normal weight (NW), overweight (OW), or type 2 diabetes mellitus (T2DM) for which each individual completed four test conditions in a randomized sequence crossover study design. The four test conditions were beverages containing stevia (75.6 mg steviol equivalents), water, glucose (30 g), and stevia+glucose (30 g glucose+75.6 mg steviol equivalents). Blood samples were collected before and for 180 min after beverage consumption. Assessments included net area under the curve (niAUC) and incremental maximal concentration values for plasma glucose, insulin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1, glucagon, and PYY. Appetite was assessed with visual-analog scale questions and energy consumption during an ad libitum meal. RESULTS: Responses to the stevia beverage did not differ significantly from those for water alone, and stevia + glucose did not differ significantly from glucose alone for any of the three groups. CONCLUSION: Acute stevia consumption did not materially alter responses for glycemia or hormones involved in glucose and appetite regulation, appetite ratings, or energy intake at a subsequent meal. Clinical Trial Registry number and website where it was obtained: Clinical Trials.gov Identifier: NCT05287906. Study Details | NCT05287906 | A Trial to Assess Steviol Glycosides on Acute Appetite Hormone Release | ClinicalTrials.gov.

Appetite↗
PubMed1978

Energy management: total program considers all building's systems.

Managing energy consumption, containing fuel usage, and preparing for alternate fuel sources are immediate areas for concern and action for all health care providers. The authors describe how they are meeting the challenge of increased energy costs and reduced availability while maintaining high-quality care by applying the concept of total energy management.

Costs and Cost Analysis↗
PubMed1975

Mathematical analysis of multienzyme systems. I. Modelling of the glycolysis of human erythrocytes.

A mathematical model for the glycolysis of human erythrocytes is presented which takes into account ATP-synthesis and -consumption. A set of three differential equations describes the steady states and the time-dependent changes of the metabolite concentrations under blood storage conditions. For a given parameter combination there are in general three stationary points of the system, one of which is unstable. At a low ATP-need the ATP-level is relatively constant for variations in the rate constant of the ATP-consuming processes. Above a critical level of the energy consumption the system breaks down. An important role of the 2.3P2G-bypass of the erythrocytes is its action as an "energy buffer", wasting ATP in case of ATP-overproduction and producing ATP in case of underproduction. A parameter combination consistent with the data on the isolated enzymes was found which gives a good agreement of theoretical predictions with the measured metabolite concentrations. Under blood preservation conditions the difference of the rates of ATP-production and -consumption is the most important factor for a high ATP-level over long periods.

Adenosine Triphosphatases↗