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M Stupfel

Publications and source records attributed to M Stupfel.

At least 19 recordsLinked to original sources
PubMed1995

Comparison of ultradian and circadian oscillations of carbon dioxide production by various endotherms.

Carbon dioxide emission (VCO2) was computed every 20 min from continuous CO2 concentration recordings taken during 3-30 consecutive days, in strictly controlled environmental conditions, in 54 OF1 mice, 99 Japanese quail, 66 Sprague-Dawley rats, 50 Hartley guinea pigs, 7 chicks, for 7-15 days on 2 Cynomolgus monkeys, and for 24 h on 7 premature infants. This VCO2 shows circadian and ultradian oscillations that were analyzed for frequencies and amplitudes in light-dark 12-h alternation (LD 12:12), continuous light (LL), and continuous dark (DD). Circadians were not always identified or were often masked in LL or DD (mostly in guinea pigs, quail, and rats), while ultradians (tau > or = 40 min) were found in all species, at every time, and in all light regimens. Analysis of variance and chi 2 show significant (P < 0.001) interspecies differences for ultradian (1.07 < tau < 1.40 h) intervals and for circadian and ultradian VCO2 amplitudes. Relationships between ultradian and circadian VCO2 oscillations differ according to the species, ultradians appearing as an entity characteristic for each endotherm species.

Activity Cycles↗
PubMed1991

The occurrence and functions of ultradian rhythms.

Ultradian oscillations with periods between 5 min and 4 h have been described in cell-free extracts, single-celled eukaryotes, cultured cells and embryos. Whereas some of these potentially oscillatory systems (e.g. glycolysis) may only exhibit this type of behaviour rarely if at all in vivo, other ultradian oscillators in lower eukaryotes are rhythms and probably have timekeeping functions. Rhythms with ultradian periods of 10 min to 20 h in oxygen consumption and carbon dioxide production have also been studied in endotherm animals: these rhythms may be modified by variations of environmental parameters and by circadian and infradian synchronizers. Interspecies and interstrain differences strongly suggest that these rhythms are endogenous and have a genetic origin. We suggest that the temporal organization of biochemical and physiological processes facilitates optimization of thermodynamic maintenance of the organism within the random fluctuations of its physicochemical environment and contributes to genetic selection.

Animals↗
PubMed1990

Ultradian, circahoral and circadian structures in endothermic vertebrates and humans.

1. For more than 30 years many studies have been carried out concerning rhythms with periods approaching 24 hr (circadian rhythms). 2. The latter have been demonstrated as resulting from environmental 24 hr synchronizers (zeitgebers), but they usually persist in the absence of a 24 hr synchronization, which proves their endogenous nature. 3. Biological rhythms with periods less than 20 hr (ultradian rhythms) and particularly those approaching 1 hr (circahoral rhythms) have been determined: for motility, rest-activity, sleep phases, endocrine secretions and other physiological functions. 4. These ultradian and circahoral rhythms have been found in rodents, birds, monkeys and humans. 5. Existing at all stages of ontogeny, they have been proved to be endogenous and species and strain specific. 6. As these ultradian rhythms can be influenced by environmental factors and sometimes by circadian rhythms they are not truly periodic, so therefore cannot be computed by the usual processes of mathematical time analysis.

Activity Cycles↗
PubMed1989

Ultradian and circadian CO2 emission variations in nocturnal and diurnal animals exposed to a light stimulus.

1. Carbon dioxide emission (VCO2) has been continuously recorded in three laboratory animal species (Sprague-Dawley rats, Japanese quail, Hartley guinea-pigs) which differ by their nocturnal and diurnal activities. A 100 lux stimulus has been delivered at various time intervals. 2. A regular alternation of 12, 3 or 1.5 hr light (L) and darkness (D) gives VCO2 circadian and ultradian rhythms of 24, 6 or 3 hr periods, respectively, in quail and rats. 3. Such circadian and ultradian LD rhythms are not induced in all guinea-pigs. 4. The amplitudes of the VCO2 responses are greatest at D----L when the animals have a maximum diurnal activity and at L----D when their maximum activity is nocturnal. 5. Interactions between circadian and ultradian rhythms are seen in all LD experiments, as well as in continuous light (LL) or continuous dark (DD). 6. No more well-marked or even inverted VCO2 responses to the light stimuli may occur after several days of exposure to these LD alternations.

Activity Cycles↗
PubMed1987

Age and survival of an acute carbon monoxide intoxication: an animal model.

Pathogen-free OF1 male and female mice of six different ages (between 31 and 387 days), grouped by 10, sex-separated and synchronized by a light (100 lux)-dark 12:12 alternation, were submitted to an acute LD50 carbon monoxide intoxication during the light period during which respiratory and motor activities are at a minimum. For this range of ages carbon monoxide survival is not significantly influenced by age and is significantly (P less than 0.001) less so in males than in females. Resistance to the acute carbon monoxide challenge seems more related to factors influencing the longevity of this mouse strain where grouped males are particularly aggressive than to respiratory exchanges (VCO2), heart frequencies or body temperature.

Aging↗
PubMed1987

Night-to-night variability of sleep respiratory pauses in normal infants.

Pneumograms have been recorded for several (6-14) consecutive nights in 11 normal children aged 1-257 days. They enabled to assess greater or equal to 5 seconds respiratory pauses. No statistical differences were found between the number of respiratory pauses per hour recorded during subsequent nights on each subject. Statistically significant (p less than 0.001) differences were found between the children either in the number of pauses or in their intervals. However, the experimental protocol does not allow to assess whether these discrepancies have a genetic, or maturational, or eventually an environmental origin.

Activity Cycles↗
PubMed1986

Starvation and respiratory rhythmic behavior in groups of light-dark synchronized Sprague-Dawley rats.

Twenty adult male SPF Sprague-Dawley rats, grouped by 5 and synchronized by a light (L)-dark (D) 12:12 alternation, were deprived of food and water for 7 days; 20 other rats were taken as controls. Continuous measurement of emitted carbon dioxide (VCO2), which was taken as an index of respiratory and metabolic exchanges, shows that starvation significantly (p less than 0.001) decreases the amplitudes of the circadian VCO2 rhythms (by 42.5% during L and 35.6% during D) and also the L----D photic VCO2 responses (by 9.2%; p less than 0.05). Concerning ultradian rhythms of mean and great periods (40 min less than tau less than 24 hr), food and water suppression diminishes their amplitudes (by 58.4% in L and 32.4% in D) and changes their phases (by a 1.29 radian advance in L and a 0.68 radian delay in D). Rats recovered their prestarvation circadian and ultradian VCO2 rhythms 6-7 days after food and water had been given back to them.

Activity Cycles↗
PubMed1986

Effects of aging on circadian and ultradian respiratory rhythms of rats synchronized by an LD12:12 lighting (L = 100 lx).

Continuous monitoring of emitted carbon dioxide (VCO2) was taken as an index of respiratory exchanges in male Sprague-Dawley rats of different ages (31-814 days) submitted to a light (100 lx)-dark (LD) 06.00-18.00 h alternation at a temperature of 20 degrees C and with food and water ad libitum. In grouped 82- and 426-day-old rats harmonic and spectral analyses show that aging decreases the amplitudes of the circadian (tau = 24 h) respiratory rhythms, decreases the amplitudes and modifies the phases of the ultradian respiratory rhythms of mean and great (10 min less than tau less than 24 h) periods. Under the environmental conditions of the experiments, the techniques utilized show no statistically significant changes with aging for the circadian rhythms and only small changes in the ultradian respiratory frequencies.

Activity Cycles↗
PubMed1986

[Respiratory ultradian variations of mean and low frequencies (from 2-80 cycles per day) in premature human infants].

Oxygen consumption (VO2) and carbon dioxide production (VCO2) were continuously measured in premature human (mean gestation age of 31 weeks at birth), nursed in incubators within a neutral thermal environment and submitted to a continuous lighting. At a mean postnatal age of 30 days, and for a mean body weight of 1.8 kg, spectral analysis shows VO2 and VCO2 ultradian variations of mean and low frequencies (2 less than f less than 80 c.day--1; i.e. periods 12 greater than t greater than 0.3 hr). It is hypothesized that these periodic variations can be compared to those previously evidenced in small laboratory vertebrates and in macaques.

Carbon Dioxide↗
PubMed1985

Sex-related factors in acute carbon monoxide intoxication in one strain of mice.

In the OF1 mouse strain, males are less resistant than females to acute carbon monoxide intoxication. Castration of males increases their resistance to carbon monoxide. For Neonates injected with four different doses of testosterone (20-500 mg per kg) or oestradiol (2-50 mg per kg), more effect on resistance to carbon monoxide in the (adult) mice was found for oestradiol than for testosterone. Pregnancy decreases resistance to carbon monoxide intoxication. Experiments performed with males and females of different ages, in various societal conditions, show the effects of sex-related dimorphism and aggressiveness. The sex-related difference in carbon monoxide resistance is not modified by a previous hypoxic stress (nitrogen hypoxia, carbon monoxide intoxication, sodium cyanide injection) but is suppressed when the CO intoxication is carried out at a low ambient temperature (13 degrees C).

Animals↗
PubMed1985

Ultradian and circadian respiratory rhythms in grouped small laboratory vertebrate species as a method to assess the effects of environmental challenges.

The recording over several days of the respiratory gases of groups of different laboratory vertebrates (mice, rats, quails), placed in a chamber with controlled ventilation, and in standardized environmental conditions of temperature, humidity, light, noise and feeding, shows ultradian (tau less than 24 hr) and circadian (tau congruent to 24 hr) rhythms. A simple variance analysis method shows periodic carbon dioxide changes, due to different environmental stimuli. Societal, light, acoustical, carbon monoxide and starvation challenges are given as examples. This technique enables us quickly to collect, on a great number of animals, data which correspond to societal behavior changes peculiar to the considered species.

Acoustic Stimulation↗
PubMed1985

Biological parameters in Japanese quail genetically selected for resistance or sensitivity to an acute hypoxic survival.

Various biological parameters were measured in two strains of Japanese quail selected for their resistance (Ls+) or susceptibility (Ls-) to an acute normobaric hypoxic challenge. Adults of these two strains showed very little or no significant differences concerning body weights, carbon dioxide emission, photoperiodic (L----D and D----L) respiratory reactions, cloacal temperatures, heart rates and ECG QRSII amplitudes, red blood cell data, hemoglobin electrophoresis, and plasma corticosterone (before and after an hypoxic challenge). Enzymatic capacities of phosphofructo-and pyruvate kinases, of glucose-6-phosphatase, lactico- and malate-dehydrogenases, measured in brains and hearts, showed but few statistically significant differences. Changing societal contacts did not suppress the differences of acute hypoxic survival between the two strains. Several statistically significant differences which concern reproduction and eggs, and especially egg laying and egg water vapor conductance were noted between the two strains.

Animals↗
PubMed1984

Respiratory behavior in groups of deaf and non-deaf GFF male mice.

Carbon dioxide emission (VCO2) of groups of 10 GFF mice, genetically deaf and non-deaf, were compared, in controlled conditions of temperature 20-21 degrees C, humidity 50-80% and light (LD12:12; L = 108 lux). A circadian rhythm of VCO2 was evidenced in both genotypes, with levels in D and in L significantly (0.001 less than p less than 0.01) greater in deaf than in non-deaf mice. Photic VCO2 variations were significantly (0.001 less than p less than 0.05) smaller at L----D and D----L in the deaf than in non-deaf genotype. Ultradian (tau greater than 20 minutes) rhythms were evidenced in both genotypes; Fourier periodic analysis showed several significant (0.001 less than p less than 0.05) differences between these 2 genotypes concerning mainly amplitudes, whilst spectral analysis showed slight frequency differences between them. Survival to an acute nitrogen hypoxia or to an acute carbon monoxide intoxication which was significantly (p less than 0.001 and p less than 0.05) lower in deaf than in non-deaf individuals confirms the differences in respiratory behavior of groups of these two strains of mice.

Acoustic Stimulation↗
PubMed1984

Effects of B16 melanoma transplantation on the respiration of grouped C57Bl female mice.

Two batches of 110 females C57Bl mice were grafted with B 16 melanoma, the first batch at the age of 67 days, the second at 82 days. The animals were divided into groups of 10, and kept under a LD 12 : 12 regimen. The growth of the tumors was more rapid in the second batch. This was accompanied in this batch, by a decrease in body growth, a diminution of heart rate and an increase in QRSII amplitude. Significant decreases in carbon dioxide emission (VCO2) level, mostly during the dark period of time, when the mice had their greatest activity, and decrease in respiratory photic variations at light transitions were obtained when the tumors were well developed. Harmonic analysis of the continuous recording of carbon dioxide shows slight changes in VCO2 ultradian (40 minutes less than tau less than 12 hours) rhythms. The effects on respiration were confirmed by different survival rates and rectal temperatures between tumor grafted and controls submitted to an acute nitrogen normobaric hypoxia.

Animals↗
PubMed1984

Sex-related factors in acute hypoxia survival in one strain of mice.

In mice of different ages from the OF1 mouse strain, males are less resistant than females to a normobaric hypoxia obtained in a few hours by a progressive lowering of normoxic PO2 with nitrogen flushing. Injection of estradiol to castrated males and spayed females increases hypoxic survival. Neonates which have been injected with a high dose of estradiol show, when adult, a high hypoxic resistance. In adult females, hypoxic survival is lower during diestrus than during estrus. Pregnancy decreases resistance to hypoxia. Experiments, performed with males and females of different ages, show the effects of sex-related dimorphism and aggressiveness. Hypoxias at various ambient temperatures demonstrate that the sex difference in hypoxic survival persists in spite of variations in rectal temperatures.

Age Factors↗
PubMed1983

Lead, cadmium, iron, zinc, copper, manganese, calcium and magnesium in SPF male rats exposed to a dilution of automotive exhaust gas throughout their lives.

Male pathogen free CFE albino Sprague Dawley rats were exposed 8 h per day, 5 days per week, for three years to a 1/1000 dilution of automotive exhaust gas, containing 58 ppm carbon monoxide, 0.37% carbon dioxide, 23 ppm nitrogen oxides, 2 ppm aldehydes, less than 5 mg/l hydrocarbons and 8.5 micrograms/m3 lead. Lead, cadmium, iron, zinc, calcium and magnesium were measured by atomic absorption in the femurs and tibias of the rats which died during the experiment. A comparison with two control groups revealed that the only significant difference in the elements measured in the bones was a 500% increase in lead concentration. The calculations of the correlations between the percentages of the elements in bones, the ages and the body weights of the rats, as well as cluster analysis, did not show consistent variations of the water, calcium, magnesium concentrations nor of the other studied metals related to this increase in lead concentration. Moreover, longevity was the same in the 3 groups of rats, but the body weight was statistically smaller (4%) in the group exposed to the auto exhaust dilution.

Age Factors↗