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Denitrification losses from outdoor piglet production: spatial and temporal variability.

Animal welfare considerations have stimulated the development of outdoor piglet (Sus scrofa) production systems, but the high levels of nutrients excreted suggest that nutrient losses from this system may be high. This study first described the spatial distribution of denitrification activity in a 5- x 5-m grid within and outside a paddock immediately after the sows (32 sows ha(-1) for 6 mo) were removed in October 1997, and again the following March. Denitrification rates averaged 0.01 kg N ha(-1) d(-1) outside, and 0.5 kg N ha(-1) d(-1) inside the paddock in October, while the corresponding figures in March were 0.01 and 0.1 kg N ha(-1) d(-1). The highest denitrification rates were observed around the feeder, and this was also the case for concentrations of dissolved organic C and inorganic N in the soil. A statistical model that included both soil parameters and distance to feeder and huts gave the best description of the variability, but there was no significant autocorrelation between sampling points. In a second phase, seasonal variation of denitrification activity within a paddock (12 sows ha(-1) yr(-1)) was quantified; 10 soil cores were sampled along a transect 11 times between March 1998 and February 1999. There was a significant positive effect of dissolved organic carbon (DOC) on denitrification at <25% gravimetric soil moisture (i.e., to November in this study). Both climate and management (position of huts and feeder) appeared to influence denitrification, which was estimated to be 69 kg N ha(-1) yr(-1), or 11% of the N surplus of this production system.

Animal Welfare↗
PubMed1984

Blood mobilization by regional vascular beds during cerebral ischemic pressor response in rabbits.

The mobilization of blood volume from regional vascular beds during cerebral ischemic pressor response was studied in anesthetized rabbits. The visceral beds of the kidney, jejunum, and liver served as volume reservoirs from which blood was mobilized during cerebral ischemia. The renal bed gave the largest volume decrease, from 24 to 13%. The magnitude of weight change in the renal and intestinal regions varied in parallel to the volemic state of the animal. Superimposition of pressure oscillation on the systemic pressor response was created by progressive restriction of the blood supply to the brain. Regional tissue weights also oscillated with a period equal to that seen in arterial pressure but almost 180 degrees out of phase. Such variations gave evidence of active venoconstriction in the reservoir response of all regional beds except the hind paw. The responses noted in the hind paw were passive except during complete restriction of the blood flow to the brain. Autoregulation of skeletal muscle and especially liver volume was present with moderate elevations in systemic arterial pressure.

Animals↗
PubMed1985

Response threshold determination of the brain stem auditory evoked response: a comparison of the phase versus magnitude derived from the fast Fourier transform.

An ensemble of 10 groups of brain stem evoked responses (BAERs), each consisting of 200 sweeps, was collected for different intensity levels and for a no-stimulus condition. A fast Fourier transform was calculated for the separate groups, which permitted a phase variance to be derived. The phase variance was compared to the magnitude value for selected frequency components making up the BAER. It was found that the phase variance was a better predictor of signal than magnitude. The superiority of prediction by phase results from intersubject variation being smaller for phase compared to magnitude.

Acoustic Stimulation↗
PubMed1988

Circadian influence on ethanol-related intrauterine growth retardation in mice.

Circadian influences on growth and development in response to ethanol were studied in mice. On gestational day 10, pregnant animals received a single intraperitoneal injection of ethanol with the following dose levels: 1.0, 2.5 or 4.0 g/kg at one of four circadian phases (0700, 1300, 1900 or 0100 hr). 48 hrs after injection the embryonic weight and length, protein and DNA content and placental weight and protein were determined. Ethanol-related intrauterine growth retardation were shown to be dose- and circadian phase-dependent, the greatest susceptibility being seen during the dark phase. The variations observed are discussed with regard to changes in drug metabolism and tissue sensitivity.

Animals↗
PubMed2006

Circadian variation in expression of G1 phase cyclins D1 and E and cyclin-dependent kinase inhibitors p16 and p21 in human bowel mucosa.

AIM: To evaluate whether the cellular proliferation rate in the large bowel epithelial cells is characterized by circadian rhythm. METHODS: Between January 2003 and December 2004, twenty patients who were diagnosed as suffering from primary, resectable, non-metastatic adenocarcinoma of the lower rectum, infiltrating the sphincter mechanism, underwent abdominoperineal resection, total mesorectal excision and permanent left iliac colostomy. In formalin-fixed and paraffin-embedded biopsy specimens obtained from the colostomy mucosa every six hours (00:00, 06:00, 12:00, 18:00 and 24:00), we studied the expression of G(1) phase cyclins (D(1) and E) as well as the expression of the G(1) phase cyclin-dependent kinase (CDK) inhibitors p16 and p21 as indicators of cell cycle progression in colonic epithelial cells using immunohistochemical methods. RESULTS: The expression of both cyclins showed a similar circadian fashion obtaining their lowest and highest values at 00:00 and 18:00, respectively (P<0.001). A circadian rhythm in the expression of CDK inhibitor proteins p16 and p21 was also observed, with the lowest levels obtained at 12:00 and 18:00 (P<0.001), respectively. When the complexes cyclins D(1) -p21 and E-p21 were examined, the expression of the cyclins was adversely correlated to the p21 expression throughout the day. When the complexes the cyclins D(1) -p16 and E-p16 were examined, high levels of p16 expression were correlated to low levels of cyclin expression at 00:00, 06:00 and 24:00. Meanwhile, the highest expression levels of both cyclins were correlated to high levels of p16 expression at 18:00. CONCLUSION: Colonic epithelial cells seem to enter the G(1) phase of the cell cycle during afternoon (between 12:00 and 18:00) with the highest rates obtained at 18:00. From a clinical point of view, the present results suggest that G(1) -phase specific anticancer therapies in afternoon might maximize their anti-tumor effect while minimizing toxicity.

Aged↗
PubMed1999

Human dynamic closed-loop accommodation augmented by sympathetic inhibition.

PURPOSE: A ciliary alpha-adrenoceptor accommodative effect has been proposed, caused by a small population of alpha1-inhibitory receptors in excised human ciliary muscle. This study was intended to investigate the effect on the closed-loop dynamic accommodative process of modulating alpha1-adrenoceptor activity by topical instillation of the alpha1-adrenergic agonist, phenylephrine hydrochloride. METHODS: A group of 10 visually normal subjects viewed a photopic (30 candela/m2) high-contrast Maltese cross, which was modulated sinusoidally (0.05-0.6Hz) and stepwise over a 2-D range (2-4 D). Monocular temporal accommodation responses were measured using a continuously recording dynamic tracking infrared optometer under two trial conditions: after instillation of saline control solution and 50 minutes subsequent to the instillation of 0.27 microl 0.4% benoxinate hydrochloride and 0.27 microl 2.5% phenylephrine hydrochloride. Pupil size and accommodative amplitude were measured at 90-second intervals for 50 minutes after drug instillation. All accommodative measurements were recorded through a fixed 4-mm pupil. RESULTS: A significant reduction in accommodative amplitude (11%; P < 0.05) was recorded, whereas pupil size showed a significant increase (33%; P < 0.05). No significant change in step-response dynamics was observed. However, phenylephrine hydrochloride caused a significant increase in accommodative gain in the low and midtemporal frequency ranges compared with the effect of a saline control treatment. No significant variation in phase lag was observed. CONCLUSIONS: For the first time in humans, this study shows that augmentation of the alpha1-inhibitory sympathetic contribution results in increased accommodative gain at low and midtemporal frequencies, which is consistent with findings in animal studies.

Accommodation, Ocular↗
PubMed2001

From slow waves to sleep homeostasis: new perspectives.

EEG slow waves are the epitome of deep nonREM sleep. The level of slow-wave activity (SWA; defined as spectral power in the 0.5-4.5 Hz band) in the initial part of sleep is determined by prior sleep and waking, and thereby represents a marker of a homeostatic sleep regulating process (Process S). Models based on SWA were successful in simulating sleep architecture in a variety of experimental protocols. SWA is an exceptional sleep variable in that it is little influenced by circadian phase and variations of the photoperiod. There is recent evidence that it is not waking per se but the absence of sleep, which engenders a rise in sleep propensity. Thus animals emerging from the hypometabolic states of hibernation or daily torpor exhibit an increase in SWA akin to sleep deprivation. Recent human studies showed SWA to be a marker of a local, use-dependent facet of sleep. Selective activation of specific cortical areas during waking enhanced SWA over the activated region during sleep. A frontal predominance of power in the 2-Hz band was documented in the initial part of a normal sleep episode. Sleep homeostasis may be a valuable concept for exploring the evolutionary origin of sleep. Thus 'rest homeostasis' has been demonstrated in invertebrate species, and the search for homologies of rest and sleep on a molecular genetic level has begun. Conceptualizing and characterizing sleep as a regulated process may eventually shed light on its function.

Animals↗
PubMed2004

[Novel matrix metalloproteinases in cycling endometrium].

OBJECTIVE: To examine the expression pattern of some novel matrix metalloproteinases (MMPs) in cycling endometrium. DESIGN: Experimental study. SETTING: Department of Obstetrics and Gynecology of the Palacky University Medical School and University Hospital, Olomouc, Czech Republic, Department of Obstetrics and Gynecology, University Hospital, Lund, Sweden. METHODS: We studied MMP-12, -16, -17, -19 and -26 mRNA in 39 normal endometrial samples obtained across the menstrual cycle. Based on histological examination, all specimens were classified according to an ideal 28 day menstrual cycle as early (n=8), mid (n=6) and late (n=7) proliferative phase, early (n=4), mid (n=4) and late (n=8) secretory phase and menstrual (n=3) phase. Cycle variation was examined in frozen samples using in situ hybridization. RESULTS: Three distinct pattern of MMP mRNA expression were detected in cycling endometrium. MMP-12 was expressed predominantly in perimenstrual period, MMP-16, -17 and 19 were expressed throughout the cycle and MMP-26 was found to be maximal in periovulatory period. CONCLUSION: Different endometrial expression patterns of novel MMPs during menstrual cycle may indicate their specific roles for menstruation, endometrial growth and remodelling and implantation.

Adult↗
PubMed2005

Aerobic granulation in a sequencing batch reactor (SBR) for industrial wastewater treatment.

Aerobic granulation seems to be an a attractive process for COD removal from industrial wastewater, characterised by a high content of soluble organic compounds. In order to evaluate the practical aspects of the process, comparative experimental tests are performed on synthetic and on industrial wastewater, originating from pharmaceutical industry. Two pilot plants are operated as sequencing batch bubble columns. Focus was put on the feasibility of the process for high COD removal and on its operational procedure. For both wastewaters, a rapid formation of aerobic granules is observed along with a high COD removal rate. Granule characteristics are quite similar with respect to the two types of wastewater. It seems that filamentous bacteria are part of the granule structure and that phosphorus precipitation can play an important role in granule formation. For both wastewaters similar removal performances for dissolved biodegradable COD are observed (> 95%). However, a relatively high concentration of suspended solids in the outlet deteriorates the performance with regard to total COD removal. Biomass detachment seems to play a non-negligible role in the current set-up. After a stable operational phase the variation of the pharmaceutical wastewater caused a destabilisation and loss of the granules, despite the control for balanced nutrient supply. The first results with real industrial wastewater demonstrate the feasibility of this innovative process. However, special attention has to be paid to the critical aspects such as granule stability as well as the economic competitiveness, which both will need further investigation and evaluation.

Aerobiosis↗
PubMed1991

Modulation of cytochemically detected dihydrofolate reductase during cell cycle.

Dihydrofolate reductase (DHFR, EC 1.5.1.3) is an important enzyme involved in DNA metabolism. In this connection the cell cycle modulation of DHFR levels in HeLa S3 and HL 60 cell lines was investigated by flow cytometric analysis. A concentration of 4 micrograms/ml of aphidicolin was employed to synchronize the cell lines. DHFR was cytochemically detected by using tetrazolium salt and immunofluorescence techniques; DNA content was evaluated by means of propidium iodide staining. At 0, 2, 4, 6, 8, 10, 12 hrs. after the removal of the drug we observed a low DHFR level in G0-G1 phase, followed by an increase during late S and G2/M phases. The variations of this enzyme may represent, under well defined conditions, a marker of cycling cells.

Cell Cycle↗
PubMed1989

Kinetics of excretion of 2-acetylaminofluorene in normal and xenobiotic-treated rats and in rats with hepatocyte nodules.

This study was designed to explore further the hypothesis that the special resistance phenotype seen in hepatocyte nodules during liver carcinogenesis could have a physiologic correlate in the manner with which a carcinogenic xenobiotic is handled. Hepatocyte nodules were induced in male rats by continuous or intermittent exposure to dietary 2-acetylaminofluorene over a 25-week period. Two or 5 weeks after the exposure, the animals were given a single dose of 9-14C-2-acetylaminofluorene. The amounts and rates of excretion of unconjugated compound and derivatives and of the glucuronic acid metabolites in the bile and urine and the amounts in the blood and liver were measured over a period of 180 minutes. For comparison, animals fed the basal diet alone, animals injected with phenobarbital or 3-methylcholanthrene, animals receiving a single dose of cobalt heme and animals fed the 2-acetylaminofluorene for only 2 weeks were studied. These groups were used as controls for different patterns of drug metabolism, especially relating to the cytochromes P-450. The nodule-bearing animals showed a pattern of handling of the carcinogen that is quite different than that of the animals of any other group. They excreted in the bile plus urine from 20 to 30% less. However, relatively much more was in the urine. The free and glucuronide-conjugated metabolic products of the carcinogen were assessed by high performance liquid chromatography. The nodule-bearing animals and the animals treated with 3-methylcholanthrene excreted much more glucuronic acid esters. The pattern of distribution of labeled 2-acetylaminofluorene is different in the nodule-bearing rats than in other animals in which variations in phase I and phase II drug-metabolizing enzymes were induced by treatment with cobalt heme, phenobarbital, 3-methylcholanthrene or short-term exposure to dietary 2-acetylaminofluorene.

2-Acetylaminofluorene↗
PubMed1986

Factors influencing in vitro sieving of blood in cerebrovascular accidents. Clinical significance and therapeutic strategy.

A haemorheological analysis with measured blood filterability was carried out on 179 patients with cerebrovascular accidents. Reduced blood filterability appeared to be related to the clinical condition: time variation (two phase course), influence of complications and of fatal prognosis. The underlying mechanism of the haemorheological disorders involved three groups of factors: quantitative and qualitative abnormalities of plasma proteins, red cells disturbances and white cells activation, leading to both local and general hyperviscosity, producing a prothrombotic state and a defective microcirculation. The haemorheological treatments are of value to the patients although the relationship between hemodilution and the filterability remains to be exactly defined, as well as a better understanding of the action of the drugs.

Blood↗
PubMed1984

Direct assay of urinary steroid glucuronides for monitoring the approach of ovulation.

The concentrations of estrone-3-glucuronide (E(1)3G) and pregnanediol-3-glucuronide (P(2)3G) in daily samples of early morning urine (EMU) were correlated with the levels of estradiol (E2), progesterone (P) and LH in respective plasma samples. Forty-six menstrual cycles were studied, in order to determine the practical usefulness of the urine assays for detecting: a) an individualized estrogen concentration threshold value, announcing the approach of ovulation. b) an individualized signal provided by P(2)3G in urine from which it can be assumed that ovulation has already occurred. The results showed that the concentration of E2 in plasma, in any day of the cycle, can be precisely inferred from the respective concentration of E(1)3G in EMU. The estimation of the plasmatic P values from those of P(2)3G in EMU had to be based on different factors according to the phase of the cycle, fact that suggests the presence of a phase-related variation in the glucuronization of P metabolites. Considering three consecutive E(1)3G urinary assay results, it was possible to identify a threshold value termed Estrogen-Peak Initiating Rise (E-PIR), which anticipated in 3.02 +/- 0.18 days the occurrence of an LH peak. The attempts to detect the occurrence of ovulation by an individualized urinary P(2)3G signal proved disappointing. The signal was detected, either before, simultaneously or after the LH peak.

Adult↗
PubMed1983

Plasma levels of growth hormone, corticosterone and insulin, during induced hepatocyte synchronization in young rats.

A wave of synchronous hepatocytes entering the cell cycle can be obtained in vivo after a subcutaneous injection (e.g. of casein) in rats at around Post-natal Day 10, when plasma growth hormone (GH) levels reach a low plateau (40 +/- 2 ng/ml) and liver cell proliferation rate is high. The present work reports the following changes in plasma hormone concentrations after synchronization of 20% of the hepatocyte population: (1) during the G1 phase (i.e. 6-12 hr after the mitogenic trigger), plasma GH concentration has dropped further (25 +/- 1.5 ng/ml). It was back to 90% of control levels during the S phase, mitosis and the following response including a transitory decrease in labelling index below control values. Injected together with the irritating mitotic trigger, a single dose of rat GH reduced the cell synchronization and post-synchronization effects by 50%. (2) Plasma corticosterone levels varied inversely to those of GH, increasing to twice the control values during G1 and were back to physiological levels when synchronized hepatocytes entered the S phase. (3) Variations in insulin levels were similar to that of corticosterone, with narrower ranges and reduced amplitudes. Our data suggest a possible correlation between the observed variations in plasma hormone levels and the induced synchronous hepatocyte response.

Animals↗