Fecal Excretion Rates Research Articles

Use of faecal excretion function for quick estimation of initial and existing lung burden for occupational exposure control due to 239Pu for S-class of intake

Two functions namely initial lung deposition and lung retention per unit faecal excretion rate are constructed primarily based on the excretion pattern of four subjects exposed to (239)Pu. In the absence of initial clear knowledge about the class of compound inhaled, faecal to urine excretion ratio was used to infer the type of inhaled class. Trends in the urine and faecal data had suggested that the intake was due to mixed class of plutonium compound for each case. With the assumption of 1:1 mixture of plutonium M&S class inhaled compound, faecal excretion rates for only S-class intake were worked out. Uptake inferred based on their urinary data had suggested it to be of similar level within 40% of uncertainty for 5 microm particle size distribution. Data, all the four cases, were pooled for analysis citing the similar level of intake, particle size distribution, nature and pattern of work. The function obtained was tested for S-class lung retention and faecal excretion rate value. These functions are handy tool for estimating initial lung burden and lung retention value for low level of S-class plutonium intake based on subject faecal analysis data.

Neonatal jaundice and stool production in breast- or formula-fed term infants

It has remained unclear whether the amount of fecal fat excreted in the stool and stool production influences the severity of neonatal jaundice. We determined the relationship between stool production, fecal fat excretion and jaundice in healthy breast-fed (BF) or formula-fed (FF) (near-)term neonates. From postnatal day 1–4, we quantitatively collected stools from 27 FF and 33 BF infants in daily fractions. Stool production and fecal fat contents were related to unconjugated bilirubin (UCB) levels, as determined by transcutaneous bilirubinometry (TcB). Bilirubin concentrations and stool production did not differ between FF and BF neonates during the study period. Neonatal bilirubin levels were not inversely correlated with stool production. FF and BF infants had similar fecal fat excretion rates. The stool production of FF infants was profoundly lower in the present study than in a 1985 study by De Carvalho et al. [J Pediatr (1985) 107:786–790]. We conclude that increased jaundice during the first postnatal days in healthy term neonates can no longer be attributed to breast-feeding and speculate that improved absorbability of formulas since 1985 has contributed to similar fat excretion and stool production in FF and BF neonates in 2007.

The lipid-lowering effect of ezetimibe in pure vegetarians

Results of previous studies have shown that ezetimibe (10 mg/day) reduces LDL cholesterol in patients with mild hypercholesterolemia on a normal-cholesterol diet (dietary intake of 200-500 mg/day) by 16-22%. However, the LDL cholesterol-lowering effect of ezetimibe in subjects with an extremely low dietary cholesterol intake (vegetarians) has not been studied. We conducted a randomized, double-blind, placebo-controlled, two-phase crossover study in 18 healthy pure vegetarians to assess the effect of ezetimibe (10 mg/day) on plasma lipids, cholesterol absorption, and its synthesis. Treatment periods lasted 2 weeks each, with an intervening 2 week washout period. Fractional cholesterol absorption was determined using the continuous dual stable isotope feeding method. Mean dietary cholesterol intake in the pure vegetarians was extremely low and averaged 29.4 +/- 16.8 and 31.4 +/- 14.4 mg/day during the placebo and ezetimibe administration phases, respectively. Fractional cholesterol absorption during the placebo phase was 48.2 +/- 8.2% and was decreased by 58% during ezetimibe treatment to 20.2 +/- 6.2% (P < 0.001). This change in intestinal cholesterol absorption was followed by a significant reduction in LDL cholesterol of 17.3%. In individuals with extremely low dietary cholesterol intake, treatment with ezetimibe (10 mg/day) leads to a significant reduction of cholesterol absorption and a clinically relevant decrease of plasma LDL cholesterol, comparable to that of subjects with a normal dietary cholesterol intake. Thus, the lipid-lowering effect of ezetimibe is mediated mainly through a reduction of the absorption of endogenous (biliary) cholesterol.

Detection System of Cryptosporidium parvum Oocysts by Brackish Water Benthic Shellfish (Corbicula japonica) as a Biological Indicator in River Water

The brackish water benthic shellfish, Corbicula japonica, was experimentally exposed to Cryptosporidium parvum oocysts at 1.51x10(4)oocysts/clam/day for 7 or 14 days. Oocysts were predominantly eliminated through the feces of Corbicula japonica in both cases by microscopic and PCR methods. The fecal excretion rates of oocysts within 4 days after the last exposure to Corbicula japonica were 87.6% for the 7-day exposure group and 86.0% for the 14-day exposure group. The tissue residue level of oocysts in the gastrointestinal tract 3 days after the last exposure was 2.7% of total exposed oocysts and that of 7 days was 1.1% for the 7-day exposure case and 1.6 and 0.5% for the 14-day exposure case, respectively, maintaining infectivity to cultured cells (HCT-8) in vitro. At the same time, field tests of Corbicula japonica for collecting oocysts showed that this clam could certainly collect Cryptosporidium parvum oocysts in the natural river and, furthermore, the gene type of C. parvum could be also identified proving its effectiveness as a biological indicator. The present study showed that the brackish water benthic shellfish Corbicula japonica may be capable of gathering and preserving Cryptosporidium parvum oocysts to a considerable extent under the natural ecological conditions, and further suggests the effectiveness of Corbicula japonica as a practical and general bioindicator for estimates of river water contamination by oocysts of Cryptosporidium parvum.

Nonabsorbable Dietary Fat Enhances Disposal of 2,2‘,4,4‘-Tetrabromodiphenyl Ether in Rats through Interruption of Enterohepatic Circulation

Polybrominated diphenyl ethers are lipophilic persistent organic pollutants (POPs), which accumulate in the environment, leading to human exposure. The compounds exert a negative impact on human health. Strategies to prevent or diminish their accumulation in humans are required. We investigated in rats whether the disposal rate of 14C-labeled tetrabromodiphenyl ether (BDE-47) could be enhanced by increasing fecal fat excretion through dietary treatment with nonabsorbable fat (sucrose polyester, SPE). As compared to control rats, SPE treatment increased fecal excretion rates of fat (+188%, p < 0.05) and 14C-BDE-47 (+291%, p < 0.05). On the basis of biliary secretion and fecal excretion rates of 14C-BDE-47, SPE effectively inhibited the enterohepatic circulation of 14C-BDE-47. In conclusion, dietary supplementation of nonabsorbable fat can enhance excretion of hydrophobic POPs by interruption of their enterohepatic circulation. Our data indicate that this strategy could decrease concentrations of hydrophobic POPs in the human body and thereby their impact on human health.

Body fat loss achieved by stimulation of thermogenesis by a combination of bioactive food ingredients: a placebo-controlled, double-blind 8-week intervention in obese subjects

A combination of tyrosine, capsaicin, catechines and caffeine may stimulate the sympathetic nervous system and promote satiety, lipolysis and thermogenesis. In addition, dietary calcium may increase fecal fat excretion. To investigate the acute and subchronic effect of a supplement containing the above mentioned agents or placebo taken t.i.d on thermogenesis, body fat loss and fecal fat excretion. In total, 80 overweight-obese subjects ((body mass index) 31.2+/-2.5 kg/m(2), mean+/-s.d.) underwent an initial 4-week hypocaloric diet (3.4 MJ/day). Those who lost>4% body weight were instructed to consume a hypocaloric diet (-1.3 MJ/day) and were randomized to receive either placebo (n=23) or bioactive supplement (n=57) in a double-blind, 8-week intervention. The thermogenic effect of the compound was tested at the first and last day of intervention, and blood pressure, heart rate, body weight and composition were assessed. Weight loss during the induction phase was 6.8+/-1.9 kg. At the first exposure the thermogenic effect of the bioactive supplement exceeded that of placebo by 87.3 kJ/4 h (95%CI: 50.9;123.7, P=0.005) and after 8 weeks this effect was sustained (85.5 kJ/4 h (47.6;123.4), P=0.03). Body fat mass decreased more in the supplement group by 0.9 kg (0.5; 1.3) compared with placebo (P<0.05). The bioactive supplement had no effect on fecal fat excretion, blood pressure or heart rate. The bioactive supplement increased 4-h thermogenesis by 90 kJ more than placebo, and the effect was maintained after 8 weeks and accompanied by a slight reduction in fat mass. These bioactive components may support weight maintenance after a hypocaloric diet.

Ezetimibe normalizes metabolic defects in mice lacking ABCG5 and ABCG8

The ATP binding cassette transporters ABCG5 (G5) and ABCG8 (G8) limit the accumulation of neutral sterols by restricting sterol uptake from the intestine and promoting sterol excretion into bile. Humans and mice lacking G5 and G8 (G5G8-/-) accumulate plant sterols in the blood and tissues. However, despite impaired biliary cholesterol secretion, plasma and liver cholesterol levels are lower in G5G8-/- mice than in wild-type littermates. To determine whether the observed changes in hepatic sterol metabolism were a direct result of decreased biliary sterol secretion or a metabolic consequence of the accumulation of dietary noncholesterol sterols, we treated G5G8-/- mice with ezetimibe, a drug that reduces the absorption of both plant- and animal-derived sterols. Ezetimibe feeding for 1 month sharply decreased sterol absorption and plasma levels of sitosterol and campesterol but increased cholesterol in both the plasma (from 60.4 to 75.2 mg/dl) and the liver (from 1.1 to 1.87 mg/g) of the ezetimibe-treated G5G8-/- mice. Paradoxically, the increase in hepatic cholesterol was associated with an increase in mRNA levels of HMG-CoA reductase and synthase. Together, these results indicate that pharmacological blockade of sterol absorption can ameliorate the deleterious metabolic effects of plant sterols even in the absence of G5 and G8.

Effects of Dietary Protein, Fat and beta-Carotene Levels on beta-Carotene Absorption in Rats

It is important that the factors influencing functional carotenoid absorption be made clear. The effect of rat diets containing different combinations of dietary protein, fat, and beta-carotene levels on beta-carotene absorption was evaluated. In the mid-level beta-carotene diet groups (1.8 mg beta-carotene/100 g diet), the retinol content in the liver and the ratio of the liver retinol content to the beta-carotene intake (namely, retinol accumulation rate) were both greater in the mid-level dietary protein groups (20 g protein/100 g diet) than in lower dietary protein groups (5 g protein/100 g diet), but were not affected by dietary fat level (10 g or 2 g fat/100 g diet). The liver beta-carotene content and its accumulation rate were lower in the mid-level dietary fat groups (10 g fat/100 g diet). beta-carotene 15,15'-dioxygenase (CDO) activity in the small intestine increased in the mid-level dietary protein groups, which resulted in an increase in the content of liver retinol converted from dietary beta-carotene. With respect to the mid-level dietary fat groups, the fecal beta-carotene excretion rate (%) increased. The low beta-carotene diet groups (0.006 mg beta-carotene/100 g diet) showed a higher serum retinol accumulation rate, CDO activity, and liver beta-carotene accumulation rate than the mid-level beta-carotene diet groups. These results suggest the marked effect of protein, fat, and beta-carotene level in diets on the absorption and metabolism of beta-carotene.

Biokinetic modeling of uranium in man after injection and ingestion

Uranium is a naturally occurring primordial radioactive element. Small amounts found in air, water, and food are regularly consumed and inhaled by humans. Even the military, medical, and industrial use of depleted uranium can affect humans. There is an appreciable retention of incorporated uranium in skeleton, kidneys, and liver, and a review of respective effective dose coefficients has been given by the International Commission on Radiological Protection (ICRP) in its "Publication 69"; however, data regarding retention in organs or tissues and rates of urinary and fecal excretion for different age groups are incomplete. Therefore, the present study provides retention data that have been calculated for uranium in all compartments and for urinary and fecal excretion, following acute and chronic injection and ingestion for six age groups. The calculations are based on the current ICRP biokinetic model for uranium, and the data can be plotted by using any mathematical software to obtain the retention data at any time after incorporation or to calculate the internal average organ dose induced by uranium provided that specific absorbed fractions are available. The dynamic relationship of the retention in plasma and blood after intravenously and orally administered uranium can easily be derived from the database for injection and ingestion. The calculated contents of uranium in organs or tissues (using the uranium concentration in foodstuffs published by UNSCEAR for Europeans) are compared with autopsy data available in the literature. According to this model, the whole body of a 75-year-old man contains 7 microg uranium, of which 76% is in the skeleton, 1% in the kidneys, and 2.1% in the liver.

Delineation of molecular changes in intrahepatic cholesterol metabolism resulting from diminished cholesterol absorption

The absorption of cholesterol by the small intestine is a major route for the net entry of cholesterol into the body and can therefore affect the plasma low density lipoprotein-cholesterol (LDL-C) concentration. These studies used ezetimibe, a potent inhibitor of cholesterol absorption, to delineate the biochemical and molecular changes in intrahepatic metabolism and biliary lipid secretion when there is a major reduction in chylomicron cholesterol delivery to the liver. In female LDL receptor (LDLR)-deficient (LDLR-/-) mice fed a basal diet containing ezetimibe (0-10 mg/day/kg body weight), cholesterol absorption was reduced up to 91%, fecal neutral sterol excretion was increased up to 4.7-fold, and plasma total cholesterol concentrations decreased by up to 18%. Blocking cholesterol absorption prevented the accumulation of very low density lipoproteins and LDL in the circulation of LDLR-/- mice fed a lipid-rich diet. In female LDLR+/+ mice fed the lipid-rich diet with ezetimibe, the relative mRNA level for the LDLR in the liver was 2-fold greater than in matching mice given the lipid-rich diet alone. We conclude that in the mouse the reduction in plasma LDL-C levels induced by blocking cholesterol absorption reflects both a diminished rate of LDL-C production and a modest increase in hepatic LDLR expression.

Effects of Bacillus polyfermenticus SCD on Lipid and Antioxidant Metabolisms in Rats Fed a High-Fat and High-Cholesterol Diet

Bacillus polyfermenticus SCD, commonly referred to as Bispan strain, is used as a host in bioindustry and has been shown to have several human health benefits. In a recent in vitro study, we discovered that B. polyfermenticus SCD exerts cholesterol-lowering and antioxidant effects. Here, we evaluate the effects of B. polyfermenticus SCD on the lipid and antioxidant metabolisms of hypercholesterolemic rats. Twenty male Sprague-Dawley rats were divided into two groups after a 1-week adaptation period and were fed for 6 weeks on either a high fat-high cholesterol diet, or a high fat-high cholesterol diet supplemented with B. polyfermenticus SCD (3.1x10(6) cfu/d). B. polyfermenticus SCD significantly reduced plasma low-density-lipoprotein cholesterol, hepatic total cholesterol, and triglycerides, while increasing the fecal excretion rates of total cholesterol and triglycerides. In addition, B. polyfermenticus SCD might reduce the risk of atherosclerosis, as the ratio of high-density-lipoprotein cholesterol to total cholesterol was significantly higher than in the control group. B. polyfermenticus SCD led to an increase in total radical trapping antioxidant potential (TRAP) and a decrease in conjugated dienes in plasma. The erythrocytic glutathione peroxidase (GSH-Px) activity in the B. polyfermenticus group was significantly lower than that in the control group. Plasma TRAP levels exhibited a highly significant negative correlation with hepatic total cholesterol and a marginally significant negative correlation with total plasma cholesterol, while a significant positive correlation was detected between fecal total cholesterol and plasma TRAP. These results suggest that B. polyfermenticus SCD exerts significant health benefits through the modulation of physiologic functions including a variety of atherogenic lipid profiles and antioxidants in hypercholesterolemia.

Exposure to Schistosoma mansoni infection in a rural area in Brazil. Part III: household aggregation of water-contact behaviour.

Much research points to the importance of the household in the study of water-borne diseases such as schistosomiasis. An important aspect of the household is the clustering of domestic activities associated with water collection, storage and usage. Such activities can result in the sharing of water-contact sites and water-contact behaviour, which expose household members to similar risks of infection. In previous studies, we determined that shared residence accounted for 28% of the variance in Schistosoma faecal egg excretion rates. We now quantify the effect of shared residence on the variation in water-related health behaviours. We found that shared residence accounted for 30% of the variation in total water contacts per week. It also accounted for a large proportion of the variation in individual water-contact behaviour: e.g. agricultural contacts (63%), washing limbs (56%) or bathing (41%). These results implicate the household as an important composite measure of the complex relationships between socioeconomic, environmental and behavioural factors that influence water-contact behaviour and, therefore, the transmission of schistosomiasis. Our results also support a focus on the household in the implementation of schistosomiasis prevention and control efforts.

Salmonella Brandenburg - emergence of a new strain affecting stock and humans in the South Island of New Zealand

AIMS: To report information on the spread of a new strain of Salmonella Brandenburg, which affected livestock and humans in the South Island of New Zealand, and a series of small case studies designed to investigate potential transmission of infection. METHODS: Information on the occurrence and spread of S. Brandenburg in livestock was gathered from laboratory diagnostic submissions, from case studies on the faecal excretion rate in ewes, carrier status of black-backed gulls (Larus dominicanus), spread of S. Brandenburg organisms in sheep yards, infection in lambs going to meat plants, and from post-abortion pathological changes in the reproductive tract of ewes. RESULTS: A newly recognised strain of S. Brandenburg was first diagnosed in aborting sheep from a flock in mid Canterbury in the South Island in 1996. Subsequently, the disease spread to other farms in mid and south Canterbury in 1997 and to Southland and Otago in the lower half of the South Island in 1998–2003. In 1999, the same strain was responsible for abortions in cattle and gastroenteritis in calves and adult cattle. The same strain of bacterium also caused disease in horses, goats, deer, pigs and humans. Spread of the disease on farms was strongly associated with aborting ewes, which resulted in considerable environmental contamination. During the abortion season, black-backed gulls appeared to spread the disease to other farms. Other potential sources of infection were carrier sheep, contaminated water sources and contaminated sheep-yard dust. Damage to the reproductive tract may affect the ability of surviving ewes to conceive. CONCLUSION: Important features of this disease are its high morbidity and mortality within a flock or herd, rapid local spread and its role as an occupational, health and safety risk to farm workers and their families.

Altered dietary iron intake is a strong modulator of renal DMT1 expression.

Divalent metal transporter1 (DMT1; also known as DCT1 or NRAMP2) is an important component of the cellular machinery responsible for dietary iron absorption in the duodenum. DMT1 is also highly expressed in the kidney where it has been suggested to play a role in urinary iron handling. In this study, we determined the effect on renal DMT1 expression of feeding an iron-restricted diet (50 mg/kg) or an iron-enriched diet (5 g/kg) for 4 wk and measured urinary and fecal iron excretion rates. Feeding the low-iron diet caused a reduction in serum iron concentration and fecal iron output rate with an increase in renal DMT1 expression. Feeding an iron-enriched diet had the converse effect. Therefore, DMT1 expression in the kidney is sensitive to dietary iron intake, and the level of expression is inversely related to the dietary iron content. Changes in DMT1 expression occurred intracellularly in the proximal tubule and in the apical membrane and subapical region of the distal convoluted tubule. Increased DMT1 expression was accompanied by a decrease in urinary iron excretion rate and vice versa when DMT1 expression was reduced. Together, these findings suggest that modulation of renal DMT1 expression may influence renal iron excretion rate.

Estimating faecal output in reindeer during winter

Faecal output (FO) was estimated indirectly in six penned male reindeer calves by use of intraruminal chromic oxide (Cr 2O 3) constant release capsules (CRCs) and compared with their actual FO, which was determined in a parallel study by use of total faecal collection (TFC) with faeces collecting bags. The captive animals successively ate two different diets: a diet of pelleted reindeer feed (RF-80) succeeded by a diet of mixed lichens. Using intraruminal CRCs to estimate FO resulted in 9.9 and 1.8 times overestimations of the FO of the animals on the RF-80 and the mixed lichen diet, respectively. The poor estimates of FO were probably caused by a faecal excretion rate of chromium that was lower than the capsule release rate given by the manufacturer of the capsules. Three of the reindeer calves were subsequently released into a free-ranging herd grazing at winter pasture. The FO of these calves and the FO of three free-ranging adult female reindeer was estimated by use of intraruminal CRCs. Actual FO was simultaneously measured in the calves by use of faeces collecting bags. Weight-specific estimates of FO was similar in free-ranging calves and adult females. The estimated and the actual FO were similar in the free-ranging calves, and the release rate of chromium from the CRCs was close to the release rate given by the manufacturer of the capsules in both calves and adult animals. It is concluded that the faecal excretion rate of chromium in reindeer being administered intraruminal CRCs depends upon the diet eaten by the animals. In future studies using intraruminal CRCs, the faecal excretion rate of marker should be measured under the trial conditions in a subset of animals to adjust marker estimates of faecal output.

Additive host genetic factors influence fecal egg excretion rates during Schistosoma mansoni infection in a rural area in Brazil.

This study quantifies the influence of shared household and kinship on egg counts during Schistosoma mansoni infection in a sample from rural Brazil. Detailed genealogic information allowed assignment of 597 individuals to 6 multihousehold pedigrees residing in 145 households. A variance component method was used to partition egg counts into shared household, additive genetic, and individual-specific environmental effects. Host additive genetic effects consistently accounted for a large proportion of the variation in egg counts: 43% in an unadjusted model and 40% in model adjusted for covariates. In a model that examined the confounding of shared household with kinship, additive genetic effects still accounted for 27% of the variation in egg counts and shared household only 12%. The consistently important role for host additive genetic factors on the variation in egg counts points to new ways of modeling and understanding the mechanisms that contribute to trait variation during infection with S. mansoni.

Pharmacokinetics of SNI-2011. (1): Absorption, Distribution, Metabolism and Excretion of 14C-SNI-2011 in Rats.

The absorption, distribution, metabolism, excretion and plasma protein binding of SNI-2011, a novel muscarinic acetylcholine receptor agonist developed as an agent improving the symptoms of dry mouth or dry eye caused by Sjogren's syndrome, were studied in rats. 1. After a single oral administration of 14C-SNI-2011 to male rats, plasma level of radioactivity reached the maximum at approximately 30 minutes, and declined by the bi-exponential manner. Oral absorption rate of radioactivity was 94%. Plasma level and pharmacokinetic parameters of radioactivity in female rats were comparable with those of male rats. 14C-SNI-2011 was considerably absorbed from duodenum, jejunum, ileum and colon. Plasma level of radioactivity at 8hr after daily oral administration of 14C-SNI-2011 increased with the number of dosing, and reached a steady state by the 3rd day. 2. After a single oral administration of 14C-SNI-2011 to male or female rats, radioactivity was distributed rapidly in whole body, and then eliminated rapidly. Tissue levels of radioactivity in male rats at 8hr after daily oral administration increased with the number of doses reaching approximately 4 times higher levels than those after the 1st administration. In pregnant rats on the 18th day of gestation, radioactivity was transferred into fetal tissues, and then decreased similarly as from maternal plasma. 3. SNI-2011 trans-sulfoxide (SNI-t-SO), SNI-2011 cis-sulfoxide (SNI-c-SO), SNI-2011 sulfone (SNI-SO2) and SNI-2011 N-oxide (SNI-NO) were identified in rat urine. As judged from the result on TLC/ radioluminography of plasma and urine samples, SNI-t-SO appeared to be the main metabolite in rats. Plasma concentration and urinary excretion rates of the unchanged SNI-2011 in female rats were higher than those in male rats. Repeated administration of SNI-2011 had no effect on liver weight, microsomal protein contents and activities of hepatic drug-metabolizing enzymes. 4. Main excretion route of 14C-SNI-2011 was urine in both of male and female rats, and approximately 100% of the dose was excreted in urine within 168 hours after administration. Fecal excretion rate of radioactivity was below 1% of the administered dose. Residual radioactivity in carcass accounted only for 0.1% of the dose. Daily urinary and fecal excretion rates of radioactivity in the period and after repeated oral administration were almost constant, and these rates were similar to those after a single administration. Radioactivity in the milk was 3.0 to 4.7 times higher than that in plasma. 5. Plasma protein binding rates of 14C-SNI-2011 in rats, dogs and human in vitro were relatively low (15.2 to 20.6%), and the binding rate was not affected by drug concentration or test species.

The excretion of biotrace elements using the multitracer technique in tumour-bearing mice

A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon 40Ar ions was used for investigation of trace element excretion into the faeces and urine of cancerous mice. The excretion rates of 22 elements (Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Mo, Nb, Tc, Ru, Ag and In) were simultaneously measured under strictly identical experimental conditions, in order to clarify the excretion behavior of these elements in cancerous mice. The faecal and urinary excretion rates of Mg, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Nb, Ru and Mo in cancerous mice, showed the in highest value at 0–8 hours. The accumulative excretion of Ca, Mo, Y and Zr was decreased and Na, Fe, Mn and Co increased in tumour-bearing mice, when compared to normal mice.

Effects of diet on titratable acid-base excretion in grasshoppers.

Despite the potential for diet to affect organismal acid-base status, especially in herbivores, little is known about the effects of diet on acid-base loading and excretion. We tested the effects of diet on acid-base loading and excretion in grasshoppers by (a) comparing the fecal acid-base content of 15 grasshopper species collected from the field and (b) comparing fecal acid-base excretion rates of Schistocerca americana grasshoppers fed vegetable diets that differed in their ashed and raw acid-base contents. The field experiments indicated that grass-feeding species excrete fairly neutral fecal pellets, while forb/mixed-feeding species vary widely in their fecal acid-base contents. In the laboratory experiment, acid-base excretion rates were positively correlated with dietary ashed base intake rates but were not correlated with the acid-base content of raw, unashed diet or feeding rate. These experiments suggest that some diets could strongly challenge the acid-base homeostasis of herbivores; in some grasshoppers, dietary acid-base loads could produce certainly lethal 1-unit changes in average body pH within 6 h if they were not excreted.

Excretion of biotrace elements using the multitracer technique in mice

A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon40Ar ions was applied to the investigation of the trace elements behavior in feces and urine of mouse. The excretion rates of 23 elements, Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Zn, Y, Zr, Mo, Nb, Tc, Ru, Ag and In were simultaneously detected under strictly identical experimental conditions, in order to clarify the excretion behavior of the elements in mice. Fecal and urinary excretion rates of the elements in mice reached the highest value separately at 48 and 24 hours. The total excretion of Mo, Tc and Co within 96 hours were all larger, more than 60%. Accumulative excretion rates of Ca, Nb, Mg, Sr, V, Sc, Na, Cr, Fe, Ag, Mn and Zr were 60-30%. The total rates of Ru, K, As, Zn, Rb, Y, Ga and In were less than 30%, and low excretion. The main excretion pathway of Mo, Co, Mg, Fe and Ag was through urine, and Na, K, As and Rb were eliminated from the body also in urine. But fecal excretion of Tc, Nb, Sr, Y, Ru, and In were larger than urinary excretion, and Ca, Sc, Mn, Zr, Zn were eliminated from the body in feces.