High Metabolism Research Articles

Toward a brain map of auditory hallucinations.

This study asks whether auditory hallucinations are reflected in a distinctive metabolic map of the brain. Regional brain metabolism was measured by positron emission tomography with [18F]-fluorodeoxyglucose in 12 DSM-III schizophrenic patients who experienced auditory hallucinations during glucose uptake and 10 who did not. All patients were free of neuroleptics and 19 had never been treated with neuroleptics. Nine patients were reexamined after 1 year to assess effects of neuroleptic treatment. Compared with the patients who did not experience hallucinations, the patients who did experience hallucinations had significantly lower relative metabolism in auditory and Wernicke's regions and a trend toward higher metabolism in the right hemisphere homologue of Broca's region. Hallucination scores correlated positively and significantly with relative metabolism in the striatum and anterior cingulate regions. Neuroleptic treatment resulted in a significant increase in striatal metabolism and a reduced frontal-parietal ratio, which was significantly correlated with a decrease in hallucination scores. Auditory hallucinations involve language regions of the cortex in a pattern similar to that seen in normal subjects listening to their own voices but different in that left prefrontal regions are not activated. The striatum plays a critical role in auditory hallucinations.

The effect of neuroleptics on dysfunction in a prefrontal substrate of sustained attention in schizophrenia

Regional brain metabolism was measured in patients with schizophrenia during the performance of auditory discrimination to evaluate the effect of neuroleptic medication on the middle prefrontal cortex, an area that appears to be an important biological determinant of the sustained attention required of subjects in this task. While unmedicated patients with schizophrenia have lower than “normal” metabolic rates in this cortical area that area unrelated to performance, patients receiving neuroleptics appear to have this metabolic deficit attenuated with higher metabolism in this area associated with greater accuracy of performance. This change occurs in the context of differential neuroleptic effects on the cortical regions of the frontal cortex, increased metabolism in the basal ganglia, thalamus and temporal lobes, and no apparent effect in the pariental and occipital cortices. The findings suggest that only part of the abnormality in the prefrontal cortex determination of sustained attention in schizophrenia is sensitive to neuroleptic treatment.

Oxygen consumption ofCallianassa kraussiStebbing (Thalassinidea, Decapoda, Crustacea) in relation to various environmental conditions

Oxygen consumption experiments were performed on the thalassinid prawn, Callianassa kraussi Stebbing, using an open flow system coupled to a Radiometer electrode and a continuous recorder. The effect of starvation, sex, body size, salinity, temperature, seasons and reduced oxygen tensions on the respiratory rates of the prawns were investigated. Of these factors, body size, temperature and seasons appeared to have the greatest effect. The results obtained showed oxyqen consumption of C. kraussi increasing with mass by the mean power of 0,72, a mean Q10 value of 2,80, a higher metabolism (at a given temperature) in winter than in summer and a similar respiration rate (at a given temperature) at salinities of 35 and 17 0/00

Salinity responses in brackish water populations of the freshwater shrimp Palaemonetes antennarius—I. Oxygen consumption

1. 1. Rapid increases in salinity result in a mean increase in oxygen consumption of 54% which returns again to the initial level after 8–10 hr. Decreases in salinity produce an increase in the metabolic rate of only 20% which returns to the initial level again after 4–8 hr. 2. 2. In steady-state experiments, the shrimps display the lowest oxygen consumption rates at low salinities. The lowest metabolic rates occur at a salinity of 2‰ and 5‰. At 20‰ the shrimps exhibit up to 30% higher metabolism. 3. 3. A comparison of three brackish water populations shows that the metabolic response to an acute change of salinity depends on the salinity to which the animals had been acclimated before. 4. On the basis of measured metabolic rates productivity estimations were undertaken and discussed in connection with earlier ecological finclings. In 19‰ brackish water Palaemonetes antennarius lives at its physiological limit. There it does not grow, loses biomass, and probably only enters this area from autumn to spring.

Androgen metabolism and apocrine differentiation in human breast cancer.

Metabolism of (7 alpha-3H)testosterone has been measured in 111 human breast cancers and compared retrospectively with the degree of apocrine differentiation in the tumors. Cancers in which apocrine characteristics were a marked feature metabolized significantly more testosterone precursor than those in which apocrine features did not predominate. Higher metabolism was accounted for by increased conversion to 5 alpha-reduced products such as 5 alpha-dihydrotestosterone and 5 alpha-androstanediols.

Fasting and maintenance metabolism of sheep

SUMMARYA series of measurements of the heat production of 16 adult sheep made at intervals of not less than 4 weeks when they were given precise amounts of different diets at about the maintenance level of nutrition were analysed statistically. The total number of observations was 365. For some sheep the observations spanned periods of more than 3 years and none spanned less than 1½ years.There were no time-related trends in the metabolizability of the gross energy of the diet. It was found that the measured heat productions, the heat productions corrected to zero energy retention and the heat productions corrected to zero feed intake (calculated fasting metabolism) were sinusoidal with time. The amplitude of the sine coefficient was about 14% of the mean value, and in some sheep there was in addition a linear secular trend. The phase of the sine function was such that minimal metabolism occurred in midwinter and maximal metabolism in midsummer.The results suggest that the seasonal variation in voluntary feed intake is associated with a similar seasonal variation in basal metabolic rate. The fact that all animals were given maintenance rations throughout further suggests that the higher metabolism is not due to higher feed intake.

Adaptive changes in cats after long-term exposure to various temperatures.

Two groups of cats were exposed to 5 and 30 degrees C, respectively for 24 mo in climatic chambers under artificial illumination. Then the ambient temperatures were reversed for both groups for another 36 mo. The group adapted to cold for 36 mo showed an increase in fur growth (+35%), an increase in resting metabolism (+20%), and a shift in threshold of the cold-induced metabolic response to 8 degrees C lower ambient temperatures. Norepinephrine (0.4 mg . kg-1) elicited nonshivering thermogenesis (+37%) in the cold-adapted animals but was ineffective in the warm-adapted ones. Fur insulation at thermoneutrality was 55% higher in the cold-adapted cats. During acute exposure to -5 degrees C, tissue insulation decreased in both groups; fur insulation increased by 34% in the warm-adapted cats but remained nearly constant in the cold-adapted animals. At all ambient temperatures cold-adapted cats had higher (+0.4 degrees C) rectal temperatures. Body weight was not significantly different in both groups, although the cats living in the cold had a 45% higher metabolism. This was compensated by an increased food consumption.

Analyse des Sauerstoffverbrauchs vonPeriplaneta americana bei konstanten und tagesperiodisch wechselnden Temperaturbedingungen

By means of the oxygen consumption, the influence of constant and diurnally alternating temperatures on the metabolism rate of the American cockroachPeriplaneta americana was investigated.By analysing the daily rhythm of the metabolism, the resting and activity phase of the animals could be distinguished.During the activity phase the level of the metabolism was determined only by the acute experimental temperature independent of the temperature pretreatment of the animals.In the resting metabolism, however, an influence of the temperature pretreatment could be shown. In nearly all experimental temperatures the metabolism of animals, pretreated at 25°C, was higher than in animals pretreated at warmer or colder temperatures. This relative high oxygen consuption of the 25°C-animals indicates that the metabolism of the cockroaches is optimally adapted only to a small temperature range of about 25°C. Animals pretreated with extremely low Temperatures (15°C) showed during the light time in warm experimental temperatures a clearly higher metabolism rate than cockroaches pretreated at 25°C, but this increase of oxygen consumption could be explained in the main by an annomal locomotory activity during the light.The mean daily oxygen consumption of nymphs, taken out of alternating temperatures, corresponds to those values which would be expected of animals, taken out of constant temperatures.Considering locomotory activity and feeding behaviour a temperature compensation, as described by Dehnel (1956) in nymphs ofPeriplaneta americana, could not be verified neither in constant nor in diurnally alternating temperatures.

Sweating in the kangaroo: a cooling mechanism during exercise, but not in the heat.

ARTICLESSweating in the kangaroo: a cooling mechanism during exercise, but not in the heatTJ Dawson, D Robertshaw, and CR TaylorTJ Dawson, D Robertshaw, and CR TaylorPublished Online:01 Aug 1974https://doi.org/10.1152/ajplegacy.1974.227.2.494MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByComparing walking and running in persistence huntingJournal of Human Evolution, Vol. 172Contributions from a Land Down Under: The Arid Continent23 September 2022Urohidrosis as an overlooked cooling mechanism in long-legged birds8 October 2021 | Scientific Reports, Vol. 11, No. 1Cats use hollow papillae to wick saliva into fur19 November 2018 | Proceedings of the National Academy of Sciences, Vol. 115, No. 49The anterior nasal region in the Red Kangaroo (Macropus rufus) suggests adaptation for thermoregulation and water conservation14 July 2017 | Journal of Zoology, Vol. 303, No. 4Thermal implications of interactions between insulation, solar reflectance, and fur structure in the summer coats of diverse species of kangaroo1 November 2016 | Journal of Comparative Physiology B, Vol. 187, No. 3Human Locomotion and Heat Loss: An Evolutionary Perspective23 December 2014Aridity, faunal adaptations and Australian Late Pleistocene extinctionsWorld Archaeology, Vol. 44, No. 1Brains, Brawn, and the Evolution of Human Endurance Running CapabilitiesDehydration, with and without heat, in kangaroos from mesic and arid habitats: different thermal responses including varying patterns in heterothermy in the field and laboratory29 June 2007 | Journal of Comparative Physiology B, Vol. 177, No. 7Ventilation patterns in red kangaroos (Macropus rufus Desmarest): juveniles work harder than adults at thermal extremes, but extract more oxygen per breath at thermoneutralityJournal of Experimental Biology, Vol. 210, No. 15Mechanisms for the control of respiratory evaporative heat loss in panting animalsDavid Robertshaw1 August 2006 | Journal of Applied Physiology, Vol. 101, No. 2Anticipatory regulation and avoidance of catastrophe during exercise-induced hyperthermiaComparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, Vol. 139, No. 4Hiperhidrosis primariaMedicina Clínica, Vol. 119, No. 17Thermoregulation in Juvenile Red Kangaroos ( Macropus rufus ) after Pouch Exit: Higher Metabolism and Evaporative Water RequirementsPhysiological and Biochemical Zoology, Vol. 74, No. 6Thermoregulation by Kangaroos from Mesic and Arid Habitats: Influence of Temperature on Routes of Heat Loss in Eastern Grey Kangaroos ( Macropus giganteus ) and Red Kangaroos ( Macropus rufus )Physiological and Biochemical Zoology, Vol. 73, No. 3Ventilatory Accommodation of Oxygen Demand and Respiratory Water Loss in Kangaroos from Mesic and Arid Environments, the Eastern Grey Kangaroo ( Macropus giganteus ) and the Red Kangaroo ( Macropus rufus )Physiological and Biochemical Zoology, Vol. 73, No. 3Energetics and biomechanics of locomotion by red kangaroos (Macropus rufus)Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, Vol. 120, No. 1Thermogenic capabilities of the opossum Monodelphis domestica when warm and cold acclimated: Similarities between american and australian marsupialsComparative Biochemistry and Physiology Part A: Physiology, Vol. 89, No. 1Thermoregulatory responses during exercise and a hot water immersion and the affective responses to peripheral thermal stimuliInternational Journal of Biometeorology, Vol. 30, No. 1Sweat and heat exchange in man and otherJournal of Human Evolution, Vol. 14, No. 1Effect of ambient temperature on autonomic thermoregulation and activity patterns in the rufous rat-kangaroo (Aepyprymnus rufescens: Marsupialia)Journal of Comparative Physiology ? B, Vol. 153, No. 2Metabolic scope and conductance in response to cold of some dasyurid marsupials and Australian rodentsComparative Biochemistry and Physiology Part A: Physiology, Vol. 71, No. 1A Possible Contribution to Heat Transfer Through the Human Skin by the Eccrine (Atrichial) Sweat GlandEffects of Adrenergic Activators and Inhibitors on the Sweat GlandsNEUROENDOCRINE CONTROL OF SWEAT GLANDSJournal of Investigative Dermatology, Vol. 69, No. 1Electron microscopy of the sweat glands from the hairy skin of the beagleBritish Journal of Dermatology, Vol. 93, No. 3 More from this issue > Volume 227Issue 2August 1974Pages 494-498 Copyright & PermissionsCopyright © 1974 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1974.227.2.494PubMed4854555History Published online 1 August 1974 Published in print 1 August 1974 Metrics

Distribution of fluorouracil-2-C 14 in hypothermicanimals with normothermic tumors

Summary It has been shown previously that normothermic tumors of deeply cooled hamsters regress and eventually disappear 6, 8 In order to induce complete disappearance of the tumors the duration of differential hypothermia must be at least 10 hrs. A more shallow differential hypothermia causes the same changes but the exposure time has to be increased from 10 to 24 hrs. 7 However, when 5-fluorouracil, an anticancer drug, is simultaneously applied with generalized body cooling and tumor warming, only 1 hr is needed to lead to the same results. The purpose of the study- reported here wasto elucidate the mechanism of tumor disappearance resulting from the combination of fluorouracil with brief differential hypothermia. As a first step in this direction the distribution of C 14 -labeled fluorouracil was studied in the organs of 10S hamsters cooled to a body temperature of 4°C while their tumors were kept normothermic. After intravenous administration of FU-2-C 14 , the radioactivity of blood of these animals remained at a high level whereas it fell quickly to very low levels in normothermic animals. It is therefore concluded that the differential hypothermia acts as a long-term systemic perfusion affecting preferentially the warm tumor tissue because of its larger blood circulation and its higher metabolism.

Queen-Rearing and the Age of Nurse Bees1

It has been established (Haydak 1961) that royal jelly produced by older nurse bees contains considerably less vitamins of the B group than that elaborated by the nurse bees of normal age. Vitamins of the B group play an important part in the coenzyme system of the cellular metabolism of living organisms. Queen larvae have a considerably higher metabolism than the worker larvae (Melampy and Willis 1939, Shuel and Dixon 1959). Therefore, it was of interest to establish whether older nurse bees can rear queens and how such queens would differ from those produced by the nurse bees of normal age.

Effect of cold acclimation on vascularization of ears, heart, liver and muscles of white rats.

The degree of vascularization of different tissues of rats killed with ether after a 4-week acclimation period to 30°C or 6°C was estimated by counting on benzidine stained cross-sections, capillaries in heart and leg muscles (soleus, gastrocnemius, plantaris), sinusoids in liver and all blood vessels in ears. Short exposure to cold (2 hr.) of the 30°C acclimated rats had no effect on the vascularization of any of the organs studied. Cold acclimation had no effect on number of capillaries in the heart and sinusoids in the liver, but in the ears it produced a 12-fold increase in number of blood vessels. In the plantaris and the red fiber regions of the gastrocnemius but not in the white fiber region of the latter, there was an absolute increase in the number of capillaries/mm2. In the soleus and the two heads of gastrocnemius, there were densely vascularized subregions which were on the average approximately 50% larger after cold acclimation. The increases in the number of opened capillaries observed in the ears and the leg muscles are interpreted as indicating a higher metabolism, and possibly an increased chemical thermogenesis in the red fiber muscles.

THE INFLUENCE OF GROWTH ON THE BASAL METABOLISM OF CHILDREN

The total metabolism of the growing child is universally admitted to be proportionately higher than that of the adult, and Benedict and Talbot 1 have shown that the basal metabolism is also considerably raised during the growth period. From their numerous observations it has been possible for them to provide us with figures showing the expected basal metabolism for any age. Although the basal metabolism for any age is fairly constant, it is probable that the difference between the basal and total metabolism varies considerably in different persons. This variation is probably due to differences of temperament and environment. The active, highly strung boy has a higher metabolism than the lethargic boy. In considering the total food requirements two other factors have to be included. These are: (1) the energy lost in the excreta (feces and urine). In neither of these excreta has complete combustion taken place, and they contain