G Kg (g + kg)

Distribution by Scientific Domains
Distribution within Earth and Environmental Science


Selected Abstracts


Carry over (transfer) of feed-borne acrylamide into eggs, muscle, serum, and faeces , a pilot study with Japanese quails (Coturnix coturnix japonica)

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-6 2005
E. Kienzle
Summary Two groups of 10 quails each were fed for 30 days on a diet containing either 663 ,g feed-borne acrylamide (AA)/kg feed (group B) or 2472 ,g AA/kg feed (group C) respectively. The concentrations of AA present in excreta and eggs were compared with those measured in eggs and excreta obtained from a control group (group A) fed on a diet low in AA (<10 ,g/kg). The results clearly showed that the eggs of quails in group C contained approximately 53,112 ,g AA/kg based on dry weight, while eggs collected from group A did not contain AA (limit of detection in eggs 3.5 ,g/kg). Nearly 5% of the AA fed was recovered in the excreta. The AA concentrations in liver, muscle and serum were detectable, but below the limit of quantitation. [source]


Influence of the dietary potassium content on transepithelial potassium transport in rat jejunum

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2000
R. Cermak
Summary In a recent study, we found that the distal rat jejunum is able to secrete K+ under in vitro conditions. The question therefore arises as to whether the small intestine might participate in K+ homeostasis. Consequently, this study examined the influence of the dietary K+ content on transepithelial K+ transport in rat jejunum. Rats were fed two diets differing in K+ content (control diet 4.0 g K+/kg, low K+ diet (LK) 0.27 g K+/kg). After a minimal feeding period of 7 days, distal jejunal sheets were mounted in Ussing chambers and unidirectional 86Rb+ fluxes (as a marker for K+ transport) were measured under short-circuit conditions. Jejunum obtained from rats fed the control diet showed a net K+ secretion of 200 nmol Rb+/h/cm2. Unidirectional Rb+ fluxes were smaller in distal jejunum from rats fed the LK diet. In these tissues, glucose-induced short-circuit current and tissue conductance were also smaller than in controls. However, net Rb+ fluxes were not significantly different in small intestine from K+ -restricted rats compared with jejunum from control animals. Based on the observation that the dietary K+ content does not affect transepithelial net K+ transport, we conclude that transcellular K+ secretion by the small intestine is not involved in K+ homeostasis. [source]


Lipid characterization of both wild and cultured eggs of cuttlefish (Sepia officinalis L.) throughout the embryonic development

AQUACULTURE NUTRITION, Issue 1 2009
A.V. SYKES
Abstract The present work reports a characterization of mean wet weight and moisture, the lipid class and fatty acid (FA) composition from the total lipids (TL), of both culture and wild eggs of the cuttlefish, Sepia officinalis, throughout the embryonic development. Additionally, reproductive data, such as the number of spawnings, number and mean weight of eggs and duration of spawning period of cultured cuttlefish is provided. Both types of eggs were similar in mean wet weight, moisture content, TL content and lipid composition throughout embryonic development. Females from the cultured group spawned 13 times and laid 8654 eggs in 64 days, with a mean weight of 0.607 0.179 g. A sex ratio of 1.57 (11, for 7,) promoted an individual fecundity of 787 eggs/, (the biggest until now on our culture facilities), which might be related to increased bottom areas. The TL increased with day/stage of embryonic development (P < 0.05) only in the cultured egg group. However, no differences were found on TL between culture and wild eggs at the same day/stage (P > 0.05). Eggs displayed predominant levels of phosphatidylcholine, phosphatidylethanolamine (PE), cholesterol and triacylglycerol at the end of embryonic development. Polar and neutral lipids of both eggs groups remained consistently proportional (,50% for each lipid fraction) and a significant increase (P < 0.05) was observed in phosphatidylserine, PE and free FA throughout the embryonic development. In either egg type and day, 16:0, 18:0, 20:5n-3 and 22:6n-3 accounted for approximately 70 g Kg,1 of all FA and saturated and n-3 totals seemed to have the same proportion in the cuttlefish eggs. The present results suggest that lipids are not used as energetic substrate but as structural components in cuttlefish egg. [source]


Involvement of cannabinoids in the cardioprotection induced by lipopolysaccharide

BRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2001
Caroline Lagneux
We have examined the involvement of the endocannabinoid system in the cardioprotection triggered by lipopolysaccharide (LPS). Rats were treated with saline or LPS (10 ,g Kg,1). 24 h later, hearts were excised, retrogradely perfused, submitted to a low-flow ischaemia (0.6 ml min,1) for 90 min and reperfused for 60 min. Some hearts were perfused with either SR 141716A (a cannabinoid CB1, receptor antagonist 1 ,M), SR 144528 (a CB2 receptor anagonist ,M), NNLA (3 ,M) or sodium nitroprusside (1 ,M) 5 min before ischaemia and during the ischaemic period. The cardioprotective effects of LPS treatment, in terms of infarction and functional recovery, were not altered by the perfusion of SR 141716A but abolished by both SR 144528 and NNLA. Finally, SR 144528 abolished the beneficial effects of SNP perfusion. Our results suggest an involvement of endocannabinoids, acting through the CB2 receptors, in the cardioprotection triggered by LPS against myocardial ischaemia. This could be attributed to a relationship between cannabinoids and NO. British Journal of Pharmacology (2001) 132, 793,796; doi:10.1038/sj.bjp.0703902 [source]


Uptake and transport of roxarsone and its metabolites in water spinach as affected by phosphate supply

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2010
Lixian Yao
Abstract Roxarsone (ROX) is widely used as a feed additive in intensive animal production. While an animal is fed with ROX, the As compounds in the manure primarily occur as ROX and its metabolites, including arsenate (As[V]), arsenite (As[III]), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA). Animal manure is commonly land applied with phosphorous fertilizers in China. A pot experiment was conducted to investigate the phytoavailability of ROX, As(V), As(III), MMA, and DMA in water spinach (Ipomoea aquatica), with the soil amended with 0, 0.25, 0.50, 1.0, and 2.0,g PO4/kg, respectively, plus 2% (w/w manure/soil) chicken manure (CM) bearing ROX and its metabolites. The results indicate that this species of water spinach cannot accumulate ROX and MMA at detectable levels, but As(V), As(III), and DMA were present in all plant samples. Increased phosphorous decreased the shoot As(V) and As(III) in water spinach but did not affect the root As(V). The shoot DMA and root As(III) and DMA were decreased/increased and then increased/decreased by elevated phosphorous. The total phosphorous content (P) in plant tissue did not correlate with the total As or the three As species in tissues. Arsenate, As(III), and DMA were more easily accumulated in the roots, and phosphate considerably inhibited their upward transport. Dimethylarsinic acid had higher transport efficiency than As(V) and As(III), but As(III) was dominant in tissues. Conclusively, phosphate had multiple effects on the accumulation and transport of ROX metabolites, which depended on their levels. However, proper utilization of phosphate fertilizer can decrease the accumulation of ROX metabolites in water spinach when treated with CM containing ROX and its metabolites. Environ. Toxicol. Chem. 2010;29:947,951. 2009 SETAC [source]


Effects of a Novel Cognition-Enhancing Agent on Fetal Ethanol-Induced Learning Deficits

ALCOHOLISM, Issue 10 2010
Daniel D. Savage
Background:, Drinking during pregnancy has been associated with learning disabilities in affected offspring. At present, there are no clinically effective pharmacotherapeutic interventions for these learning deficits. Here, we examined the effects of ABT-239, a histamine H3 receptor antagonist, on fetal ethanol-induced fear conditioning and spatial memory deficits. Methods and Results:, Long-Evans rat dams stably consumed a mean of 2.82 g ethanol/kg during a 4-hour period each day during pregnancy. This voluntary drinking pattern produced a mean peak serum ethanol level of 84 mg/dl. Maternal weight gain, litter size and birth weights were not different between the ethanol-consuming and control groups. Female adult offspring from the control and fetal alcohol-exposed (FAE) groups received saline or 1 mg ABT-239/kg 30 minutes prior to fear conditioning training. Three days later, freezing time to the context was significantly reduced in saline-treated FAE rats compared to control. Freezing time in ABT-239-treated FAE rats was not different than that in controls. In the spatial navigation study, adult male offspring received a single injection of saline or ABT-239 30 minutes prior to 12 training trials on a fixed platform version of the Morris Water Task. All rats reached the same performance asymptote on Trials 9 to 12 on Day 1. However, 4 days later, first-trial retention of platform location was significantly worse in the saline-treated FAE rats compared control offspring. Retention by ABT-239-treated FAE rats was similar to that by controls. ABT-239's effect on spatial memory retention in FAE rats was dose dependent. Conclusions:, These results suggest that ABT-239 administered prior to training can improve retention of acquired information by FAE offspring on more challenging versions of hippocampal-sensitive learning tasks. Further, the differential effects of ABT-239 in FAE offspring compared to controls raises questions about the impact of fetal ethanol exposure on histaminergic neurotransmission in affected offspring. [source]


Cardio-respiratory reflexes evoked by phenylbiguanide in rats involve vagal afferents which are not sensitive to capsaicin

ACTA PHYSIOLOGICA, Issue 1 2010
A. Dutta
Abstract Aim:, Stimulation of pulmonary C fibre receptors by phenylbiguanide (PBG, 5-HT3 agonist) produces hypotension, bradycardia and tachypnoea or apnoea. However, tachypnoeic or apnoeic responses are not consistent. Therefore, this study was undertaken to delineate the actions of PBG on respiration and compared with those evoked by capsaicin (TRPV1 agonist). Methods:, Blood pressure, respiratory excursions and ECG were recorded in urethane anaesthetized adult rats. The effect of PBG or capsaicin was evaluated before and after ondansetron (5-HT3 antagonist), capsazepine (TRPV1 antagonist) or bilateral vagotomy. In addition, their effect on vagal afferent activity was also evaluated. Results:, Bolus injection of PBG produced concentration-dependent (0.1,100 ,g kg,1) hypotensive and bradycardiac responses, while there was tachypnoea at lower concentrations (0.1,3 ,g kg,1) and apnoea at higher concentrations (10,100 ,g kg,1). After vagotomy or after exposure to ondansetron both tachypnoeic and apnoeic responses were abolished along with cardiovascular responses. However, capsazepine (3 mg kg,1) did not block the PBG-induced reflex responses. Capsaicin (0.1,10 ,g kg,1), on the other hand, produced a concentration-dependent apnoea, hypotension and bradycardia but tachypnoea was not observed. Ondansetron failed to block the capsaicin-induced reflex response while bilateral vagotomy abolished bradycardiac and hypotensive responses and attenuated the apnoeic response. In another series, vagal afferent activity and cardio-respiratory changes evoked by PBG were blocked by ondansetron. However, capsaicin failed to activate the PBG-sensitive vagal afferents even though cardio-respiratory alterations were observed. Conclusions:, The present observations indicate that PBG produced tachypnoea at a lower concentration and apnoea at a higher concentration involving vagal afferents which are different from those excited by capsaicin. [source]


Effects of repeated injections of fibroblast-stimulating lipopeptide-1 on fever, formation of cytokines, and on the responsiveness to endotoxin in guinea-pigs

ACTA PHYSIOLOGICA, Issue 1 2009
A. Greis
Abstract Aims:, We investigated, whether the Toll-like receptors (TLRs)-2/6-agonist fibroblast-stimulating lipopeptide-1 (FSL-1), like the TLR-4 agonist lipopolysaccharide (LPS), induces a state of tolerance. We further tested the influence of repeated pre-treatment with FSL-1 on the animals' responsiveness to LPS. Methods:, Abdominal temperature was recorded in unrestrained guinea-pigs with intra-abdominally implanted radiotransmitters. Circulating concentrations of tumour necrosis factor (TNF) and interleukin-6 (IL-6) were measured with specific bioassays. We tested the effects of intra-arterial (i.a.) or intraperitoneal (i.p.) injections of 100 ,g kg,1 FSL-1, repeated five times at intervals of 3 days. The animals' responses to i.a. or i.p. injections of 10 ,g kg,1 LPS were determined another 3 days later and compared to those of nave guinea-pigs. Results:, The FSL-1-induced TNF peak was significantly attenuated starting with the third i.a. administration, while fever was unimpaired and the IL-6-peak just tended to decrease. Fever and IL-6 in response to i.a. injections of LPS were identical in both groups, while circulating TNF was higher in nave compared to FSL-1 pre-treated animals. The effects of repeated i.p. injections of FSL-1 were more pronounced resulting in attenuation of fever as well as circulating TNF and IL-6, the strongest reduction observed after the third stimulation with FSL-1. Repeated i.p. pre-treatment with FSL-1 induced hyporesponsiveness to i.p. administration of LPS compared to nave animals with regard to fever and especially with regard to LPS-induced formation of cytokines. Conclusions:, There is a development of tolerance to FSL-1 and cross-tolerance between FSL-1 and LPS depending on the route of administration of the respective TLR-2/6 and TLR-4 agonists. [source]


Adenosine infusion attenuates soluble RAGE in endotoxin-induced inflammation in human volunteers

ACTA PHYSIOLOGICA, Issue 1 2009
A. Soop
Abstract Aim:, To evaluate possible anti-inflammatory effects of pre-treatment with adenosine in a human experimental inflammatory model. Methods:, The study design was double-blind, crossover, placebo-controlled and randomized. In the Intensive Care Unit of a university hospital, 16 healthy male volunteers were treated for 5.5 h with infusions of adenosine 40 ,g kg,1 min,1 or placebo. Thirty minutes after the start of adenosine or placebo, 2 ng kg,1E-Coli endotoxin was administered. Heart rate, body temperature, blood pressure, plasma cytokines (TNF-,, IL-6 and IL-10), soluble RAGE and resistin, exhaled nitric oxide and nitrite/nitrate in urine were determined. Results:, Endotoxin elicited the expected clinical signs of an inflammatory reaction (tachycardia, fever) and led to prominent release of the cytokines studied (P < 0.001). Resistin in plasma increased after endotoxin (P < 0.001). After placebo treatment, soluble RAGE (sRAGE) in plasma increased 5 h after the endotoxin challenge (P < 0.001) but not after adenosine. After placebo, orally exhaled NO increased with a peak at 4 h (P < 0.001), although there was no statistically significant difference between the two treatments. Nitrite/nitrate in urine (n = 11) did not differ between adenosine and placebo treatments. Conclusion:, In conclusion, adenosine infusion starting before endotoxin challenge in humans attenuated sRAGE significantly but otherwise had no clear anti-inflammatory effect. Adenosine as a potential anti-inflammatory treatment in humans needs further study, including use of higher doses. The mechanism underlying the effect of adenosines on sRAGE remains unknown. [source]


B2 kinin receptors mediate the Indian red scorpion venom-induced augmentation of visceral reflexes via the nitric oxide cyclic guanosine monophosphate pathway

ACTA PHYSIOLOGICA, Issue 4 2009
S. Kanoo
Abstract Aim:, This study was performed to delineate the kinin (receptor)-dependent pathways in the Indian red scorpion (Mesobuthus tamulus; MBT) venom-induced pulmonary oedema as well as the augmentation of cardio-pulmonary reflexes evoked by phenyldiguanide (PDG). Methods:, In urethane-anaesthetized adult rats, the effect of venom on the PDG reflex responses (blood pressure, heart rate and respiration rate) and the pulmonary water content was ascertained using various antagonists(des- Arg, B1 receptor antagonist; Hoe 140, B2 receptor antagonist; N, -nitro- l -arginine methyl ester (l -NAME), nitric oxide (NO) synthase inhibitor; methylene blue, soluble guanylate cyclase inhibitor; and glibenclamide, K+ATP channel blocker). The effect of phosphodiesterase V inhibitor (sildenafil citrate) on the reflex response and the pulmonary water content was also examined and compared with venom-induced responses. Results:, Intravenous injection of PDG (10 ,g kg,1) evoked apnoea, bradycardia and hypotension lasting >60 s. Exposure to MBT venom (100 ,g kg,1) for 30 min augmented the PDG reflex responses by two times and increased the pulmonary water content, significantly. Hoe 140 blocked the venom-induced responses (augmentation of PDG reflex and increased pulmonary water content) whereas des-Arg did not. l -NAME, methylene blue or glibenclamide also blocked the venom-induced responses. Furthermore, sildenafil citrate (that increases cGMP levels) produced augmentation of PDG reflex response and increased the pulmonary water content as seen with venom. Conclusion:, The results indicate that venom-induced responses involve B2 kinin receptors via the NO-dependent guanylate cyclase-cGMP pathway involving K+ATP channels. [source]


Left ventricular mechanical dyssynchrony is load independent at rest and during endotoxaemia in a porcine model

ACTA PHYSIOLOGICA, Issue 4 2009
R. A'roch
Abstract Aim:, In diseased or injured states, the left ventricle displays higher degrees of mechanical dyssynchrony. We aimed at assessing mechanical dyssynchrony ranges in health related to variation in load as well as during acute endotoxin-induced ventricular injury. Methods:, In 16 juvenile anaesthetized pigs, a five-segment conductance catheter was placed in the left ventricle as well as a balloon-tipped catheter in the inferior vena cava. Mechanical dyssynchrony during systole, including dyssynchrony time in per cent during systole and internal flow fraction during systole, were measured at rest and during controlled pre-load reduction sequences, as well as during 3 h of endotoxin infusion (0.25 ,g kg,1 h,1). Results:, Systolic dyssynchrony and internal flow fraction did not change during the course of acute beat-to-beat pre-load alteration. Endotoxin-produced acute pulmonary hypertension by left ventricular dyssynchrony measures was not changed during the early peak of pulmonary hypertension. Endotoxin ventricular injury led to progressive increases in systolic mechanical segmental dyssynchrony (7.9 1.2,13.0 1.3%) and ventricular systolic internal flow fraction (7.1 2.4,16.6 2.8%), respectively for baseline and then at hour 3. There was no localization of dyssynchrony changes to segment or region in the ventricular long axis during endotoxin infusion. Conclusion:, These results suggest that systolic mechanical dyssynchrony measures may be load independent in health and during acute global ventricular injury by endotoxin. More study is needed to validate ranges in health and disease for parameters of mechanical dyssynchrony. [source]


Vacuolar H+ -ATPase expression is increased in acid-secreting intercalated cells in kidneys of rats with hypercalcaemia-induced alkalosis

ACTA PHYSIOLOGICA, Issue 4 2007
W. Wang
Abstract Aims:, Hypercalcaemia is known to be associated with systemic metabolic alkalosis, although the underlying mechanism is uncertain. Therefore, we aimed to examine whether hypercalcaemia was associated with changes in the expression of acid,base transporters in the kidney. Methods:, Rats were infused with human parathyroid hormone (PTH, 15 ,g kg,1 day,1), or vehicle for 48 h using osmotic minipumps. Results:, The rats treated with PTH developed hypercalcaemia and exhibited metabolic alkalosis (arterial HCO: 31.1 0.8 vs. 28.1 0.8 mmol L,1 in controls, P < 0.05, n = 6), whereas the urine pH of 6.85 0.1 was significantly decreased compared with the pH of 7.38 0.1 in controls (P < 0.05, n = 12). The observed alkalosis was associated with a significantly increased expression of the B1-subunit of the H+ -ATPase in kidney inner medulla (IM, 233 45% of the control level). In contrast, electroneutral Na+ -HCO cotransporter NBCn1 and Cl,/HCO anion exchanger AE2 expression was markedly reduced in the inner stripe of the outer medulla (to 26 9% and 65 6%, respectively). These findings were verified by immunohistochemistry. Conclusions:, (1) hypercalcaemia-induced metabolic alkalosis was associated with increased urinary excretion of H+; (2) the increased H+ -ATPase expression in IM may partly explain the enhanced urinary acidification, which is speculated to prevent stone formation because of hypercalciuria and (3) the decreased expression of outer medullary AE2 suggests a compensatory reduction of the transepithelial bicarbonate transport. [source]


Platelet activating factor (PAF) increases plasma protein extravasation and induces lowering of interstitial fluid pressure (Pif) in rat skin

ACTA PHYSIOLOGICA, Issue 1 2005
V. V. Iversen
Abstract Aim:, To investigate the ability of the microdialysis technique to measure capillary selectivity of different sized plasma proteins induced by local administration of platelet activating factor (PAF). Methods:, We used hollow plasmapheresis fibres with 3 cm membrane (cut off 3000 kDa) placed on the back of anaesthetized rats. Results:, Platelet activating factor (50 ,g mL,1) administered locally via the fibre, increased extravasation of radiolabelled 125I-HSA from plasma to the microdialysis fibre by approximately 900% compared both to baseline and the control fibre within 70 min (n = 6, P < 0.05). The extravasation in the control fibre did not change over time. HPLC measurement of plasma proteins in the microdialysis perfusate also demonstrated decreased capillary selectivity for proteins in the diameter range of 73 , 56 and 39 after local administration of PAF (n = 6, P < 0.05). PAF also significantly lowered interstitial fluid (Pif) pressure after subcutaneous administration (50 ,g mL,1). Mean arterial pressure (MAP) after intravenous injection of PAF (0.4 ,g kg,1) fell instantly by about 50 mmHg, and stabilized at 50 mmHg after 15 min (n = 6). MAP was unaltered when PAF was given through the microdialysis fibre (n = 4). Both total tissue water (TTW) and extravasation of albumin, measured as the plasma-to-tissue clearance (E-alb) showed a significant increase after PAF (n = 7, P < 0.05). Conclusions:, The present study demonstrates that PAF induces plasma protein extravasation and decrease capillary selectivity of different sized plasma proteins. It also increases transcapillary fluid flux, and lowers Pif, indicating a role for PAF in the interstitium for generation of transcapillary transport of water and large molecules followed by formation of oedema. [source]


Nerve growth factor increases airway responses and decreases levels of exhaled nitric oxide during histamine challenge in an in vivo guinea-pig model

ACTA PHYSIOLOGICA, Issue 2 2001
S. G. Friberg
There is a growing body of evidence supporting the idea that nerve growth factor (NGF) may be involved in the development of asthma-associated symptoms, such as airway hyper-responsiveness. Increased levels of NGF have recently been described in serum and in the airways of asthmatics. We have examined whether exhaled nitric oxide (NO) levels might be altered during the increased airway responses upon NGF treatment in guinea-pigs in vivo. Intravenous (i.v.) administration of histamine normally elicits a rapid peak in insufflation pressure (IP) and in exhaled NO, followed by a period of decreased concentrations of exhaled NO. Anaesthetized guinea-pigs were pre-treated intravenously with either saline, 4 or 80 ng kg,1 NGF 30 min before i.v. challenge with 16 ,g kg,1 histamine. At 80 ng kg,1 NGF significantly enhanced the airway obstruction caused by histamine, whereas the peak acute increase in exhaled NO was not enhanced. Following the increase, came a rapid drop, an effect enforced in the NGF treated animals. Subsequently, the time to return to 90% of resting exhaled NO was increased, from 12 min in saline-treated animals to 48 min in NGF-treated animals. Our data confirm that NGF can enhance airway responses to histamine. Moreover, our study shows a decrease in exhaled NO following a histamine challenge, an effect enhanced by NGF. A reduced ability to release exhaled NO may be a mechanism for increased airway responses during elevated NGF levels. The interaction between NGF and airway NO formation, and its relation to airway responses, merit further investigation. [source]


Influence of neurohumoral blockade on heart rate and blood pressure responses to haemorrhage in isoflurane anaesthetized rats

ACTA PHYSIOLOGICA, Issue 3 2000
UllmanArticle first published online: 24 DEC 200
Four groups of Sprague,Dawley rats were anaesthetized with isoflurane (ISO) (1.7% end-tidal concentration) in 40% oxygen, and mechanically ventilated. The animals were bled 15 mL kg,1 b.w. from the femoral vein over 10 min, followed by an observation period of 30 min. Ten minutes before haemorrhage each group of animals was pre-treated with intravenous injection/infusion of either: isotonic saline (Group B; CON; n=7), vasopressin V1 -receptor antagonist [d(CH2)5Tyr(Me)AVP; 10 ,g kg,1] (Group C; AVP-a; n=7), the non-selective angiotensin II receptor antagonist saralasin (10 ,g kg,1 min,1) (Group D; SAR; n=7) or hexamethonium (10 mg kg,1) (Group E; HEX; n=7). A separate group of conscious animals were pre-treated with isotonic NaCl and subjected to the same haemorrhage protocol (Group A; AW; n=7). Mean arterial pressure (MAP), heart rate (HR) and blood gases were observed during the experiments. Only pre-treatment with SAR and HEX reduced MAP significantly. The pre-haemorrhage HR was only affected by HEX, which caused a reduction by 17%. The HR was significantly lower at the end of haemorrhage compared with pre-haemorrhage levels in all groups except that group treated with HEX. In that group the HR changed in the opposite direction. The ability to maintain MAP during haemorrhage, and the post-haemorrhage period, was significantly impaired in the groups treated with AVP-a, SAR or HEX compared with the group receiving NaCl. It is concluded that autonomic nervous activity is of major importance for the maintenance of MAP during isoflurane anaesthesia, whereas circulating angiotensin II and vasopressin levels contribute to a much smaller degree in this regard. General anaesthesia in combination with different degrees of neurohumoral blockade impairs the haemodynamic responses to blood loss, seen in conscious individuals. The impairment involves both the early and late phases during haemorrhage, as well as the post-bleeding recovery period. All three neurohumoral systems (autonomic nervous activity, angiotensin II and vasopressin) are of importance for regulating MAP during and after haemorrhage, although the autonomic nervous outflow appears to contribute to a larger extent. [source]


Oral toxicity of the cyanobacterial toxin cylindrospermopsin in mice: Long-term exposure to low doses

ENVIRONMENTAL TOXICOLOGY, Issue 6 2006
A. Sukenik
Abstract The hepatotoxin cylindrospermopsin, a sulfated-guanidinium alkaloid with substituted dioxypyrimidine (uracil) moiety, was isolated from several cyanobacteria species. The acute toxicity of cylindrospermopsin was well established based on intraperitoneal and oral exposure; however, only a few long-term subacute exposure studies were performed to permit a reliable guideline value for cylindrospermopsin in drinking water. In the study reported herein, female and male mice were exposed to cylindrospermopsin in their drinking water. Cylindrospermopsin-containing, Aphanizomenon ovalisporum (cyanobacterium)-free medium was provided as the only source of drinking water, whereas a control group was given a fresh medium for cyanobacteria as drinking water. Over a period of 42 weeks, experiment groups were exposed to cylindrospermopsin concentration, gradually increased from 100 to 550 ,g L,1 (daily exposure ranged between 10 and 55 ,g kg,1 day,1). Body and organ weights were recorded, and serum and hematology analyses were performed 20 and 42 weeks after the beginning of the experiment. The most pronounced effect of cylindrospermopsin was elevated hematocrit levels in both male and female mice after 16 weeks of exposure to cylindrospermopsin. The observed changes in the hematocrit level were accompanied by deformation of red blood cells, which were changed into acanthocyte. Based on these results, a daily cylindrospermopsin dose of 20 ,g kg,1 day,1 (equivalent to 200 ,g L,1) is proposed as the lowest-observed-adverse-effect level for both male and female mice. 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 575,582, 2006. [source]


Toxicity of arsenic species to Lemna gibba L. and the influence of phosphate on arsenic bioavailability

ENVIRONMENTAL TOXICOLOGY, Issue 1 2004
Martin Mkandawire
Abstract The toxicity of arsenic (As) species to Lemna gibba L. and the influence of PO on As bioavailability and uptake were tested in batch culture. L. gibba were exposed to six test concentrations of NaHAsO4 7H2O and NaAsO3, with 0, 0.0136, 13.6, and 40 mg L,1 KH2PO4. In batch culture As toxicity to L. gibba did not relate linearly to As concentration. The growth rate, related to frond number as recommended by OECD and ISO/DIN, was significantly inhibited in fronds exposed to 20,50 ,g L,1 As(III) compared with fronds exposed to As(V). The growth rate was stimulated when plants were exposed to 50,250 ,g L,1 of both As(III) and As(V). After exposure to 300,800 ,g L,1 growth inhibition was significantly higher for As(III) than for As(V), whereas above 800 ,g L,1 As(V) was inhibited the most. The bioaccumulation of As(III) and As(V) was significantly higher for P-deficient cultures (0.98 0.08 and 1.02 0.19 g kg,1, respectively for 0.0136 mg L,1 PO) than for P-sufficient cultures (243 and 343 mg kg,1 for 40 mg L,1, respectively). Plants exposed to As(V) had uptake and accumulation values slightly higher than did plants exposed to As(III). No significant differences in bioaccumulation were found between plants exposed to a concentration of As(III) >1 mg L,1 and those exposed to As(V) at the same concentration. This indicates a direct relationship to P content in the culture. Toxicity may result from the uptake of As(V) instead of PO as a result of ion competition during uptake because of close thermodynamic properties, which may change the interaction among components in the media. The toxicity pattern is interpreted as a manifestation of changing speciation in the batch culture and of the oxidation of As(III) to As(V) in an oxygen-rich environment. 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 26,34, 2004. [source]


Oral toxicity of the cyanobacterial toxin cylindrospermopsin in male Swiss albino mice: Determination of no observed adverse effect level for deriving a drinking water guideline value

ENVIRONMENTAL TOXICOLOGY, Issue 2 2003
A. R. Humpage
Abstract The cyanobacterial toxin cylindrospermopsin (CYN) is a frequent contaminant of freshwaters throughout the world, including those that are sources of drinking water. The first cases of human poisoning attributed to this toxin occurred from a treated drinking water supply in Queensland, Australia, in 1979. The toxin causes extensive damage to the liver, kidneys, spleen, heart, and other organs. It is known to be a potent protein synthesis inhibitor, but there is mounting evidence for genotoxicity and that it metabolizes to even more toxic forms. As part of a risk assessment process leading to a guideline for a safe drinking water level for this toxin, we performed a series of experiments to determine a no-observed-adverse-effect level (NOAEL) for this toxin. In the first trial male mice were exposed to CYN-containing cyanobacterial extract in their drinking water (0,657 ,g CYN kg,1 day,1) for 10 weeks. In the second trial mice received purified CYN by daily gavage (0,240 ,g CYN kg,1 day,1) for 11 weeks. Body and organ weights were recorded; urine, serum, and hematology analyses were performed; and histopathological examination of tissues was carried out. Body weights were significantly increased at low doses (30 and 60 ,g kg,1 day,1) and decreased at high doses (432 and 657 ,g kg,1 day,1). Liver and kidney weights were significantly increased at doses of 240 ,g kg,1 day,1 and 60 ,g kg,1 day,1, respectively. Serum bilirubin levels were significantly increased and bile acids significantly decreased at doses of 216 ,g kg day,1 and greater. Urine total protein was significantly decreased at doses above 60 ,g kg,1 day,1. The kidney appeared to be the more sensitive organ to this toxin. If it is assumed that increased organ weights and changes in functional capacity are responses to an underlying toxic effect, then the NOAEL based on this data is 30 ,g kg,1 day,1, which, with standard calculations and uncertainty factors, provides a proposed guideline safety value of 1 ,g/L in drinking water. 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 94,103, 2003. [source]


Effect of preoperative prophylaxis with filgrastim in cancer neck dissection

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2000
Wenisch
Background Cancer surgery is known to lead to a deterioration in host defence mechanisms and an increase in susceptibility to infection after operation. Filgrastim enhances important antimicrobial functions of neutrophils including chemotaxis, phagocytosis and oxidative killing mechanisms. Methods The effects of additional (all patients received perioperative 3 , 25 mg kg,1 cefotiam and 1 , 20 mg kg,1 metronidazole) preoperative prophylaxis with filgrastim (5 ,g kg,1 12 h prior to surgery plus 5 ,g kg,1 0 h prior to surgery) on neutrophil phagocytosis and reactive oxygen radical production and postoperative infections in 24 patients undergoing cancer neck dissection were studied. Phagocytic capacity was assessed by measuring the uptake of fluorescein isothiocyanate-labelled Escherichia coli and Staphylococcus aureus by flow cytometry. Reactive oxygen generation after phagocytosis was estimated by determining the amount of dihydrorhodamine 123 converted to rhodamine 123, intracellularly. Results In the filgrastim-treated patients a higher neutrophil phagocytic capacity was seen intraoperatively, and 1,5 days postoperative, but not prior to surgery. Reactive oxygen radical production was significantly higher in filgrastim-treated patients prior to surgery, intraoperative and postoperative (1,5 days). 2/12 (17%) patients had postoperative infections in the filgrastim group and 9/12 (75%) patients had infections in the placebo group (P < 0.001). In particular, wound infections were recorded more often in the placebo group (1/12 vs. 6/12; P = 0.004). Conclusion We conclude that filgrastim enhances perioperative neutrophil function and could be useful in the prophylaxis of postoperative wound infections in patients undergoing cancer neck dissection. [source]


Distribution of polycyclic aromatic hydrocarbons in particle-size separates and density fractions of typical agricultural soils in the Yangtze River Delta, east China

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2008
J. Z. Ni
Summary Soil organic matter can be divided into different organic carbon (C) pools with different turnover rates. The organic pollutants in soils associated with these organic C pools may have different bioavailability and environmental risks during the decomposition of soil organic matter. We studied the distribution patterns of 15 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in different particle-size separates (clay, fine silt, coarse silt, fine sand and coarse sand) and density fractions (light and heavy fractions) of nine agricultural topsoils (0,20 cm depth) from a contaminated area in the Yangtze River Delta region of east China. There was a decreasing trend in PAH concentration in particle-size separates with decreasing particle size. However, the different particle-size separates had similar PAH composition. The concentration of PAHs in the light fraction ranged from 13 037 to 107 299 ,g kg,1, far higher than in the heavy fraction, which ranged from 222 to 298 ,g kg,1. Although the light fraction accounted for only 0.4,2.3% of the soils, it was associated with 31.5,69.5% of soil PAHs. The organic matter in coarse silt had the strongest capacity for enrichment with PAHs. Combining the distributions of PAHs and the turnover rates of organic matter in different soil fractions, the environmental risks of PAH-polluted soils may be due mainly to the PAHs associated with sand and the light fraction. [source]


Increase in the fracture toughness and bond energy of clay by a root exudate

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 5 2008
B. Zhang
Summary Root exudates help drive the formation of the rhizosphere by binding soil particles, but the underlying physical mechanisms have not been quantified. This was addressed by measuring the impact of a major component of root exudates, polygalacturonic acid (PGA), on the interparticle bond energy and fracture toughness of clay. Pure kaolinite was mixed with 0, 1.2, 2.4, 4.9 or 12.2 g PGA kg,1 to form test specimens. Half of the specimens were washed repeatedly to remove unbound PGA and evaluate the persistence of the effects, similar to weathering in natural soils. Fracture toughness, KIC, increased exponentially with added PGA, with washing increasing this trend. In unwashed specimens KIC ranged from 54.3 2.5 kPa m,1/2 for 0 g PGA kg,1 to 86.9 4.7 kPa m,1/2 for 12.2 g PGA kg,1. Washing increased KIC to 61.3 1.2 kPa m,1/2 for 0 g PGA kg,1 and 132.1 4.9 kPa m,1/2 for 12.2 g PGA kg,1. The apparent bond energy, ,, of the fracture surface increased from 5.9 0.6 J m,2 for 0 g kg,1 to 12.0 1.1 J m,2 for 12.2 g kg,1 PGA in the unwashed specimens. The washed specimens had , of 13.0 1.9 J m,2 for 0 g kg,1 and 21.3 2.6 J m,2 for 12.2 g PGA kg,1. Thus PGA, a major component of root exudates, has a large impact on the fracture toughness and bond energy of clay, and is likely to be a major determinant in the formation of the rhizosphere. This quantification of the thermodynamics of fracture will be useful for modelling rhizosphere formation and stability. [source]


Effect of organic matter applications on 13C-NMR spectra of humic acids of soil

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2008
S. Dou
Summary Much attention has been paid to improving soil fertility with organic matter (OM) application, which not only deals with organic wastes and protects the environment, but also maintains soil fertility and increases crop yields. Much research has also been on the effects of OM applications on the soil's physical, chemical and biological properties, but relatively less attention has been spent on humic substance (HS). In order to clarify the mechanism of improving soil fertility by applying OM, we analysed the changes of structural characteristics of humic acid (HA) from OM applications to soils by 13C-NMR, chemical analysis, thermal analysis, optical properties, IR and fluorescence spectroscopy. Samples of a brown soil (Paleudalf) and a paddy soil (an anthropogenic soil originating from Udifluvents) were collected from the plough layer of the long-term field experiment at Shenyang Agricultural University and Liaoning Provincial Alkali-Saline Soil Institute, respectively. Both field experiments included three treatments each: (i) brown soil, zero-treatment (CKbr) and two pig manure (PM) applications (O1 and O2) at annual rates of 0.9 t ha,1 and 1.8 t ha,1 of organic carbon, respectively; and (ii) paddy soil, zero-treatment (CKpad), pig manure (Op) and rice straw (Or) at annual rates of 2.62 t ha,1 and 1.43 t ha,1 of organic carbon, respectively. An incubation experiment was also carried out to test the field experiment on the brown soil, namely four treatments: zero-treatment (CKc), and three pig manure applications at rates of 30 g kg,1 (C1), 50 g kg,1 (C2) and 70 g kg,1 (C3), respectively. The total incubation was 180 days. The results indicated that number-average molecular weights (Mn), total acidity, aromaticity, excitation maximum wavelength (,Exmax), and the heat ratio of the high to moderate temperature exothermic regions (H3/H2) of the HA all decreased after OM application. The degree of activation (AD), the absorption intensity ratio of 2920 cm,1 to 1720 cm,1 in infrared spectra (IR2920/1720), alkyl C and O-alkyl C of the HA increased. The HA structure tended to become simpler and more aliphatic. [source]


Interactions of ferricyanide with humic soils and charred straw

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2008
T. Rennert
Summary The iron-cyanide complexes ferricyanide, [FeIII(CN)6]3,, and ferrocyanide, [FeII(CN)6]4,, are anthropogenic contaminants in soil. We studied the interactions of ferricyanide with humic soils and charred straw (maize and rye, both charred at 300, 400 and 500C) by batch experiments and Fourier transform infrared (FTIR) spectroscopy. All soil samples sorbed ferricyanide (up to 8.4 g kg,1). Precipitation of a manganese ferrocyanide after reduction of ferricyanide in the moderately acidic to neutral soils was deduced from both FTIR spectroscopy (CN absorption bands at 2069,2065 cm,1) and geochemical modelling. Ferricyanide was also adsorbed onto the charred straw. The amounts of iron-cyanide complexes adsorbed increased with increasing charring temperature, with a maximum of 1.71 g kg,1. An absorption band at 2083 cm,1 indicated weakly adsorbed intermediates of the reduction of ferricyanide to ferrocyanide. This band disappeared in the samples charred at higher temperature, whereas a band at 2026 cm,1 was present in all spectra and became intensified in the high-temperature straw. We attribute this band to ferrocyanide forming inner-sphere complexes, presumably with quinone species of the organic matter. The band at 2026 cm,1 was also present in the spectra of the soils, indicating that soil organic matter also adsorbs ferrocyanide. However, in humic soils the main processes of ferricyanide interaction include reduction to ferrocyanide and precipitation as manganese ferrocyanide. Quantitatively, adsorption on highly aromatic substances plays only a less important role as compared with precipitation. [source]


Laser-induced breakdown spectroscopy for soil diagnostics

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2001
J. Bublitz
Summary Laser-optical measurements and fibre optics are potentially attractive tools for applications in soil science because of their great sensitivity and selectivity and their capabilities for on-line and in situ analysis. We have investigated laser-induced breakdown spectroscopy (LIBS) for the quantitative detection of metal ions on the surface of natural soil samples from two sites (Hohenschulen and Oderbruch, Germany). The LIBS technique allows the spatially resolved investigation of adsorption and desorption effects of ions in soil. A frequency doubled (532 nm) and Q-switched Nd:YAG laser with a pulse duration of 8 ns is focused on the soil surface and induces a plasma. Typical power densities are 150 mJ mm,2. The plasma emission is recorded in time and spectrally resolved by a gateable optical multichannel analyser (OMA). A delay time of about 500 ns between laser pulse and OMA gate was used to resolve single atomic and ionic spectral lines from the intense and spectrally broad light that is emitted by the plasma itself. The dependency of the LIBS signal of a single spectral line on the amount of water in the sample is investigated in detail. The results indicate that quenching of water in the plasma plume reduces the line intensities, while the interaction with aquatic colloids increases the intensity. The two processes compete with each other, and a non-linear correlation between measured line intensities and the amount of water in the sample is obtained. This is verified by a simple computer simulation and has to be taken into account for the quantitative interpretation of LIBS signals, e.g. when absolute concentrations are estimated. In the present investigation natural calcium concentrations <,2 ,g kg,1 were measured with the LIBS technique in the samples for the two test sites. In addition, measurements were made with dry and water-saturated BaCl2 mixed soil samples, and no significant difference in the detection limit for barium was obtained. [source]


Modelflow estimates of cardiac output compared with Doppler ultrasound during acute changes in vascular resistance in women

EXPERIMENTAL PHYSIOLOGY, Issue 4 2010
Kenneth S. Dyson
We compared Modelflow (MF) estimates of cardiac stroke volume (SV) from the finger pressure-pulse waveform (Finometer) with pulsed Doppler ultrasound (DU) of the ascending aorta during acute changes in total peripheral resistance (TPR) in the supine and head-up-tilt (HUT) postures. Twenty-four women were tested during intravenous infusion of 0.005 or 0.01 ,g kg,1 min,1 isoprenaline, 10 or 50 ng kg,1 min,1 noradrenaline and 0.3 mg sublingual nitroglycerine. Responses to static hand-grip exercise (SHG), graded lower body negative pressure (LBNP, from ,20 to ,45 mmHg) and 45 deg HUT were evaluated on separate days. Bland,Altman analysis indicated that SVMF yielded lower estimates than SVDU during infusion of 0.01 ,g kg,1 min,1 isoprenaline (SVMF 92.7 15.5 versus SVDU 104.3 22.9 ml, P= 0.03) and SHG (SVMF 78.8 12.0 versus SVDU 106.1 28.5 ml, P < 0.01), while larger estimates were recorded with SVMF during ,45 mmHg LBNP (SVMF 52.6 10.7 versus SVDU 46.2 14.5 ml, P= 0.04) and HUT (SVMF 59.3 13.6 versus SVDU 45.2 11.3 ml, P < 0.01). Linear regression analysis revealed a relationship (r2= 0.41, P < 0.01) between the change in TPR from baseline and the between-methods discrepancy in SV measurements. This relationship held up under all of the experimental protocols (regression for fixed effects, P= 0.46). These results revealed a discrepancy in MF estimates of SV, in comparison with those measured by DU, during acute changes in TPR. [source]


Neostigmine and pilocarpine attenuated tumour necrosis factor , expression and cardiac hypertrophy in the heart with pressure overload

EXPERIMENTAL PHYSIOLOGY, Issue 1 2008
Jessica Freeling
The inflammatory cytokine tumour necrosis factor , (TNF,) is known to be a major factor contributing to cardiac remodelling and dysfunction. Parasympathetic nervous system cholinergic function can inhibit TNF, expression during systemic infection. In the present study, we tested the effects of a cholinesterase inhibitor, neostigmine, and a muscarinic cholinergic agonist, pilocarpine, on cardiac hypertrophy and TNF, levels during pressure overload. Rats with transverse aortic constriction exhibited elevated TNF, protein levels in the heart, increased heart weight to body weight ratios (an index of cardiac hypertrophy) and decreased left ventricular diastolic function. Two weeks of infusion with neostigmine (6 ,g kg,1 day,1) or pilocarpine (0.3 mg kg,1 day,1) significantly reduced cardiac hypertrophy, reduced TNF, levels and elevated interleukin-10 levels in heart tissues, and improved ventricular function in rats with transverse aortic constriction. Neither of these treatments significantly changed ventricular pressure load. Furthermore, in primary cultured neonatal cardiac cells, treatment with pilocarpine attenuated adrenergic agonist phenylephrine-induced increased TNF, expression and [3H]leucine (a marker of protein synthesis) incorporation in the cells. Collectively, both cholinergic agents decreased TNF, levels and attenuated cardiac hypertrophy. Since both agents potentially enhanced cholinergic function, the anti-inflammatory action may be involved in the cardioprotective effect of the treatments with these agents. [source]


Nitric oxide and thyroid gland: modulation of cardiovascular function in autonomic-blocked anaesthetized rats

EXPERIMENTAL PHYSIOLOGY, Issue 3 2004
Andrea Lorena Fellet
We have previously reported that acute administration of NG -nitro- l -arginine methyl ester (l -NAME) increases the mean arterial pressure (MAP) and heart rate (HR) in autonomic-blocked (CAB) anaesthetized rats. In the present study we examined whether thyroid and adrenal glands are involved in these pressor and chronotropic responses. Sprague-Dawley rats were studied after bilateral vagotomy and ganglionic blockade with hexamethonium (10 mg kg,1), and stabilization of MAP with infusion of phenylephrine (PE) (6 ,g kg,1 min,1). The rats were divided into groups: L, CAB; PE, CAB + PE bolus (6 ,g kg,1); L-TX, thyroidectomy + CAB; L-AX, adrenalectomy + CAB; TX, only thyroidectomy; C, CAB. L, L-AX and L-TX groups received a bolus of l -NAME (7.5 mg kg,1). Triiodothyronine (T3), thyroxin (T4) and thyrotropin (TSH) levels were measured in L and L-TX rats before and after l -NAME administration. Reduced nicotamide adenine dinucleotide (NADPH) diaphorase activity was determined in heart and aorta of the TX group. The pressor response induced by l -NAME was similar in all groups. l -NAME-induced-tachycardia was associated with this rise in MAP. Adrenalectomy did not modify this chronotropic response, but it was attenuated by thyroidectomy. Thyroidectomy by itself decreased the circulating levels of T3 but it had no effect on the plasma levels of T4 and TSH. L and L-TX groups showed similar levels of circulating T4 and TSH, meanwhile the plasma level of T3 decreased in the L group. Nitric oxide synthase (NOS) activity in atria as well as in aorta was greater in the TX group compared with C. When autonomic influences are removed, the thyroid gland modulates intrinsic heart rate via a mechanism that involves, at least in part, the nitric oxide pathway. [source]


Nitric oxide-dependent protein synthesis in parotid and submandibular glands of anaesthetized rats upon sympathetic stimulation or isoprenaline administration

EXPERIMENTAL PHYSIOLOGY, Issue 2 2004
Shariel Sayardoust
In anaesthetized female rats, the ,-adrenoceptor agonist isoprenaline was intravenously infused (20 ,g kg,1 min,1) for 30 min or the ascending cervical sympathetic nerve trunk was intermittently stimulated (50 Hz, 1 s every tenth second) on one side for 30 min. The incorporation of [3H]leucine into trichloroacetic acid (TCA)-insoluble material was used as an index of protein synthesis. In response to isoprenaline, the [3H]leucine incorporation increased by 79% in the parotid glands and by 82% in the submandibular glands. The neuronal type NO-synthase inhibitor N-PLA, reduced (P < 0.001) this response to 26% and 20%, respectively. Sympathetic stimulation under ,-adrenoceptor blockade increased the [3H]leucine incorporation by 192% in the parotid glands and by 35% in the submandibular glands. N-PLA reduced the corresponding percentage figures to 86% (P < 0.01) and 8% (P < 0.05). When tested in the parotid glands, the non-selective NO-synthase inhibitor L -NAME reduced (P < 0.01) the nerve-evoked response to 91%. The increase in [3H]leucine incorporation in response to sympathetic stimulation under ,-adrenoceptor blockade was not affected by N-PLA in the parotid (139%versus 144%) and submandibular glands (39%versus 34%). In non-stimulated glands, the [3H]leucine incorporation was not influenced by the NO-synthase inhibitors. In conclusion, ,-adrenoceptor mediated salivary gland protein synthesis is largely dependent on NO generation by neuronal type NO-synthase, most likely of parenchymal origin. [source]


Route of Administration Differentially Affects Fevers Induced by Gram-Negative and Gram-Positive Pyrogens in Rabbits

EXPERIMENTAL PHYSIOLOGY, Issue 3 2002
T. Cartmell
We have investigated the febrile responses of New Zealand White rabbits to a Gram-negative pyrogen (bacterial lipopolysaccharide (LPS) from Salmonella typhosa), commonly associated with systemic infection, and a Gram-positive pyrogen (Staphylococcus aureus), more frequently associated with superficial soft tissue infection, each administered via one of four different routes (intravenous, intramuscular, subcutaneous or intraperitoneal) at each of three different doses (LPS: 0.1, 1 and 10 ,g kg,1; S. aureus: 1.5 107, 1.5 108 and 1.5 109 cell walls kg,1). Intravenous administration of LPS evoked rapid, dose-dependent biphasic fever. Injection of LPS by the other routes also evoked dose-dependent fever. However, these fevers were monophasic, had increased latency of onset, and were of lower amplitude. It is important to note that a dose of approximately 10 and 100 times that of the standard intravenous dose was required to produce a similar peak rise in temperature when administered subcutaneously and intraperitoneally, respectively. Intravenous injection of the highest dose of S. aureus evoked dose-dependent biphasic fever, with short latency of onset, which was very similar to that induced by intravenous LPS. At lower doses, intravenous S. aureus induced monophasic fever. No fever occurred when the same doses of S. aureus were administered by any other route. We conclude that any of the four routes may be used for the study of LPS-induced fever, provided that the doses are adjusted. However, studies of S. aureus -induced fever, and detection of contamination with either pyrogen, requires intravenous injection. [source]


Corn stover feedstock trials to support predictive modeling

GCB BIOENERGY, Issue 5 2010
DOUGLAS L. KARLEN
Abstract To be sustainable, feedstock harvest must neither degrade soil, water, or air resources nor negatively impact productivity or subsequent crop yields. Simulation modeling will help guide the development of sustainable feedstock production practices, but not without field validation. This paper introduces field research being conducted in six states to support Sun Grant Regional Partnership modeling. Our objectives are to (1) provide a fundamental understanding of limiting factor(s) affecting corn (Zea mays L.) stover harvest, (2) develop tools (e.g., equations, models, etc.) that account for those factors, and (3) create a multivariant analysis framework to combine models for all limiting factors. Sun Grant modelers will use this information to improve regional estimates of feedstock availability. A minimum data set, including soil organic carbon (SOC), total N, pH, bulk density (BD), and soil-test phosphorus (P), and potassium (K) concentrations, is being collected. Stover yield for three treatments (0%, 50%, and 90% removal) and concentrations of N, P, and K in the harvested stover are being quantified to assess the impact of stover harvest on soil resources. Grain yield at a moisture content of 155 g kg,1 averaged 9.71 Mg ha,1, matching the 2008 national average. Stover dry matter harvest rates ranged from 0 to 7 Mg ha,1. Harvesting stover increased N,P,K removal by an average of 42, 5, and 45 kg ha,1 compared with harvesting only grain. Replacing those three nutrients would cost $53.68 ha,1 based on 2009 fertilizer prices. This first-year data and that collected in subsequent years is being used to develop a residue management tool that will ultimately link multiple feedstock supplies together in a landscape vision to help develop a comprehensive carbon management plan, quantify corn stover harvest effects on soil quality, and predict regional variability in feedstock supplies. [source]