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PubMed1950

Studies on entry and egress of poliomyelitis infection. III. Excretion of the virus during the presymptomatic period in parenterally inoculated monkeys.

Excretion of poliomyelitis virus has been demonstrated in monkeys after four different parenteral routes of inoculation. Virus has been found in both the pharyngeal secretions and the stools after infraorbital nerve dip and after inoculation of the Gasserian ganglion; in the pharyngeal secretions after intrathalamic inoculation; and in the stools after inoculation of the celiac ganglion. Excretion began as early as the 2nd and as late as the 7th day after inoculation, in all instances before the onset of symptoms. The immediate source of the excreted virus appeared to be infected peripheral ganglia with neural connections to the mucous membranes of the upper and lower portions of the alimentary tract, notably the pharynx. Primary infection of the body surfaces was excluded in the experiments and therefore could not account for the excretion of virus. The mode of elimination was probably by centrifugal spread through axons of peripheral nerve fibers and not by way of the blood stream or lymphatics. Evidence was obtained that when excretion of virus has once occurred, reinvasion from the implicated surface to other, previously uninfected peripheral ganglia ensues, thus providing new sources for excretion and other potential pathways for invasion of the CNS. It is suggested that such reinvasion may occur serially until the immunological defenses come into play. Our experiments lend support to the view that during the initial stage of poliomyelitis, and perhaps throughout its course in some cases, e.g. the asymptomatic and the mild cases without central nervous symptoms, infection is confined to the peripheral nervous system. Involvement of the CNS when it occurs is a secondary phase of the infective process and is not a necessary prelude to elimination of the virus. Excretion is explainable on the basis of the established neurocytotropism and axonal conduction of the virus without resort to the hypothesis of extraneural infection.

Animals↗
PubMed1997

Thyrotropin and thyroglobulin as an index of optimal iodine intake: correlation with iodine excretion of 39,913 euthyroid patients.

The recommendations for the dietary allowance of iodine are 150 micrograms per day for adolescents and adults. Thyrotropin (TSH) and thyroglobulin (Tg) can be used as surveillance indicators for assessing iodine deficiency disorders. We compared the relation between TSH and Tg, free triiodothyronine, and thyroxine serum levels with urinary iodine excretion in 2311 untreated euthyroid patients using our modified cericarsenite method. An adequate iodine intake may be assumed when TSH and Tg values are at the lower end of the normal range. Patients were grouped according to urinary iodine excretion and goiter size. In the group with an iodine excretion between 201 and 300 micrograms of iodine per gram of creatinine, the lowest TSH values and even low Tg levels could be shown. We conclude that an iodine intake of approximately 250 micrograms/day is associated with the lowest TSH stimulation to thyrocytes. In the groups separated according to thyroid size, significantly higher Tg levels were found in the patients with uninodular and multinodular goiter as a result of longstanding iodine deficiency, whereas actual urinary iodine excretion did not differ significantly. Additionally, iodine excretion of 39,913 euthyroid patients between 1984 was 1996 was examined. In Austria iodized salt (10 mg KI/kg) was introduced by law in 1963 and increased to 20 mg KI/kg salt in 1990. An initial increase of iodine excretion until 1993 was followed by a decrease in 1994 and 1995 without further changes in 1996. These results show that iodine intake has improved since 1984; however, in 1996 iodine excretion in one-third of the investigated patients was under 100 micrograms per gram of creatinine and more than 80% had less than 200 micrograms per gram of creatinine.

Adult↗
PubMed1976

Greater bile acid excretion with soy bean than with cow milk in infants.

The excretion of fecal sterols and bile acids was measured in five infants from the 1st week of life to 2 or 3 months of age as the composition of their diet was changed from cow milk to soy bean milk. Bile acid excretion, adjusted for body weight, was initially lower during the 1st than during the 3rd week, when it reached adult values. The average excretion of bile acids was 6.8 mg/kg per day with soy bean milk and 3.6 mg/kg per day with cow milk. Net sterol excretion (total sterol output minus cholesterol intake) was also twice as high with soy bean milk and probably reflected enhancement of cholesterol re-excretion as well as of synthesis since the cholesterol content of soy beans is nil. However, net sterol excretion remained higher with soy bean than with cow milk even when egg yolk cholesterol was added to the soy bean milk. It is concluded that the substitution of soy bean milk for cow milk, which lowered the plasma cholesterol in all infants (even in the presence of dietary cholesterol) leads to an increase in bile acids and probably also in cholesterol excretion in young infants.

Animals↗
PubMed1979

The short-term effects of protein intake on 3-methylhistidine excretion.

The urinary excretion of 3-methylhistidine is used as a convenient index of muscle protein catabolism. Histidine is methylated in peptide linkage within muscle protein, and is quantitatively excreted when the protein is catabolized. 3-Methylhistidine would be expected to be present in ingested muscle protein, and unless altered in the digestive process, to be excreted as a function of intake. We studied its excretion at four levels of mixed protein intake, in separate groups of obese subjects, on the 1st day of altered input, with and without concurrent energy provision. A significant (P less than 0.001) linear relationship between protein intake and 3-methylhistidine excretion was observed, with a mean excretion of 198 mumoles/day at 0 intake, and an increment of 1.34 mumoles/g of ingested protein. There was no relationship between its excretion and the concurrent nitrogen balance. Thus, estimates of muscle protein catabolism with this method require that muscle protein be absent from the diet or its contribution quantified.

Adult↗
PubMed1982

Arm muscle indicators and creatinine excretion in children.

The ability of anthropometric measurements, including arm muscle area calculated from arm circumference and triceps skinfold thickness, to estimate creatinine excretion as an index of muscle mass was tested in 14 fully active children, 2 to 6 yr of age in a residential care facility. The children were placed on a meat and fish-free diet for 36 to 48 h before the determination of mean creatinine excretion during three 24-h urinary collections. Results indicated highly significant correlations between mean creatinine excretion and height (r = 0.71), weight (r = 0.69), and arm circumference (r = 0.63). However, arm muscle area had the highest correlation with creatinine excretion (r = 0.86) of any anthropometric variable used. Step-wise multiple-regression analysis indicated that including height or weight with arm muscle area did not significantly improve the estimation of creatinine excretion, but that weight for height added significantly to improve the estimation of creatinine excretion, but that arm muscle area can provide a useful index of body muscle as reflected in urinary creatinine excretion in young children.

Arm↗
PubMed1985

Exercise and protein intake effects on urinary 3-methylhistidine excretion.

A 28-day study was conducted with 13 adult men to determine the effect of weight lifting exercise and protein intake level on urinary 3-methylhistidine (3MH) excretion. Subjects were fed the RDA for protein [0.8 g/(kg BW X d)] or 3 X RDA; there were no-exercise and exercise groups at each intake. Comparisons of last 14-day, least-squares means among groups did not reveal differences in data treated by lean body weight [3MH/(kg LBW X d)] or by urinary creatinine excretion [3MH/(kg UCE X d)], but 3MH/(kg LBW X d) excretions were higher for exercise than no-exercise subjects. Regression analyses revealed linear, increasing trends in the 3MH/(kg LBW X d) data for RDA-exercise (p less than 0.03), 3 X RDA-exercise (p less than 0.01), and 3 X RDA-no-exercise (p less than 0.01) groups; 3MH/(g UCE X d) group data plots overlapped. Our findings for 3MH/(kg LBW X d) indicate that a weight lifting program was associated with increased 3MH excretions from adult males. As an index of skeletal muscle catabolism, an increase in 3HM excretion represents an increase in tissue catabolism. No significant effect of 3 X RDA protein intake on last 14-day 3MH excretions was observed; however, linear increases in 3MH/(kg LBW X d) for 3 X RDA-no-exercise subjects suggests a relationship. Trends of exercise- or protein intake-enhanced 3MH excretion could be masked by data as 3MH/(g UCE X d) if exercise or 3 X RDA protein intake can expand the body creatine pool independent of skeletal muscle mass.

Adolescent↗
PubMed2006

Lignan and isoflavone excretion in relation to uterine fibroids: a case-control study of young to middle-aged women in the United States.

BACKGROUND: Uterine fibroids are hormonally responsive; estradiol and progesterone stimulate their growth, and gonadotrophin-releasing hormone agonists shrink them. Phytoestrogens, including isoflavones and lignans, can act as weak estrogens or antiestrogens. OBJECTIVE: The objective of this case-control study was to evaluate the relation between uterine fibroid risk and phytoestrogen exposure. DESIGN: Two overnight urine collections (48 h apart) from 170 uterine fibroid cases and 173 controls were analyzed for isoflavonoids (ie, daidzein, genistein, equol, and O-desmethylangolensin) and lignans (enterodiol and enterolactone). Logistic regression was used to determine associations between the mean excretion of the 2 collections and the risk of uterine fibroids. RESULTS: Unadjusted isoflavone excretion did not differ significantly between cases and controls (2.33 +/- 5.82 and 2.60 +/- 5.90 nmol/mg Cr, respectively; P = 0.68), but cases excreted significantly less lignans than did controls (2.86 +/- 3.45 and 4.57 +/- 6.67 nmol/mg Cr, respectively; P < 0.01). The trend for a reduced risk of uterine fibroids with increasing quartiles of lignan excretion was significant (odds ratio for highest versus lowest quartile = 0.31; 95% CI: 0.17, 0.58; P for trend < 0.01). When adjusted for age, BMI, race, family history of uterine fibroids, and isoflavone excretion, this trend remained but was attenuated (P = 0.07). CONCLUSIONS: Our findings suggest a modest inverse association between lignan excretion and uterine fibroid risk. Whether this relation represents an effect of lignans per se or of other constituents of lignan-containing foods on the development of uterine fibroids remains to be determined. No association was found between isoflavone excretion and uterine fibroids; however, the intake of soy foods, the primary source of isoflavones, was low in this population.

Adult↗
PubMed1995

Urinary excretion of 3-methyladenine and 3-ethyladenine after controlled exposure to tobacco smoke.

The urinary excretion of the DNA alkylation products 3-methyladenine (3-MeAde) and 3-ethyladenine (3-EtAde) after controlled exposure to cigarette smoke over a period of 4 days was determined by competitive radioimmunoassay after separation by HPLC. Twenty-four hour urine samples were collected from five smokers and five non-smokers. Days 1 and 3 (control days) were without smoking, on days 2 and 4 smokers consumed 24 cigarettes each within 8 h in an unventilated room (45 m3) in the presence of non-smokers. Average levels of carbon monoxide during exposure were 15-20 p.p.m., 2.8-3.5 mg/m3 of respirable suspended particles and 75-86 micrograms/m3 of nicotine. Carboxyhemoglobin levels increased by 9.0 and 1.8% in smokers and passive smokers respectively. On control days, urinary excretion of 3-MeAde was similar in smokers and non-smokers (4.7-6.2 micrograms/24 h). Smoking resulted in a significant increase (P < 0.01) in 3-MeAde excretion (13.6-14.8 micrograms/24 h); no change was observed in the average excretion of 3-MeAde by passive smokers (4.8-4.9 micrograms of 3-MeAde/24h). Baseline 3-EtAde excretion on control days was similar in smokers and passive smokers (13.7-32.8 ng/24 h). In smokers, the amount of urinary 3-EtAde was increased > 5-fold (119.3-138.5 ng/24 h) on smoking days; no effect on 3-EtAde excretion was observed on average in passive smokers (18.0-25.2 ng/24 h). The nature of the DNA-reactive agent(s) responsible for the increased urinary excretion of 3-alkyladenines, in particular of the sensitive indicator 3-EtAde, remains to be determined.

Adenine↗
PubMed1998

Effect of smoking cessation on oxidative DNA modification estimated by 8-oxo-7,8-dihydro-2'-deoxyguanosine excretion.

BACKGROUND: Reactive oxygen species from, e.g. tobacco smoke are suggested to be involved in carcinogenesis by oxidative modification of DNA. The urinary excretion rate of the oxidized nucleoside 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) has been validated as a biomarker of the rate of oxidative DNA modification with mechanistic relation to carcinogenesis. In cross-sectional studies, the urinary excretion rate of 8-oxodG has been shown to be elevated in smokers compared with non-smokers. PURPOSE: In this randomised, controlled smoking cessation study, we investigated whether cigarette smoking per se causes oxidative DNA modification. METHODS: Of the 182 healthy smokers included, 100 were randomized to quit smoking after baseline samples had been taken, and 82 were randomized to continue usual smoking. Before the start of the study and after 4 weeks, the subjects collected 24-h urine samples that were analysed for 8-oxodG content by high-pressure liquid chromatography with electrochemical detection. The subjects randomized to smoking cessation were followed up after 26 weeks. RESULTS: Four weeks of smoking cessation resulted in a 21% decrease in 8-oxodG excretion rate (from mean +/- SD, 30.5 +/- 13.9 to 24.1 +/- 10.5 nmol/24 h, P < 0.001) in 58 quitters included in per-protocol data analysis. Sixty-five continued smokers included in per-protocol analysis showed a 9% decrease in 8-oxodG excretion rate (from 31.6 +/- 13.2 to 28.7 +/- 12.6 nmol/24 h, P = 0.026). After 4 weeks, the 8-oxodG excretion rate was 16% (95% confidence interval 4 to 28%) higher in the continued smokers than in the quitters (P = 0.0085, ANCOVA), demonstrating the effect of smoking per se. A 23% (P < 0.005) decrease in 8-oxodG excretion rate was sustained for 26 weeks in 27 quitters who completed the study. CONCLUSION: Smoking cessation significantly reduces the urinary excretion rate of 8-oxodG, giving direct and controlled evidence that cigarette smoking causes an increased rate of oxidative DNA modification. This could represent a mechanism by which tobacco smoke is carcinogenic.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2005

Prospective study of 8-oxo-7,8-dihydro-2'-deoxyguanosine excretion and the risk of lung cancer.

Oxidative damage to DNA may be important in carcinogenesis and a possible risk factor for lung cancer. The urinary excretion of products of damaged nucleotides in cellular pools or in DNA may be important biomarkers of exposure to relevant carcinogens reflecting the rate of damage in steady state and may predict cancer risk. Oxidation of guanine in DNA or the nucleotide pool may give rise to 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) for urinary excretion. Oxoguanine glycosylase (OGG1) is the base excision enzyme repairing 8-oxodG in DNA by release of 8-oxoguanine. In a nested case-cohort design we examined associations between urinary excretion of 8-oxodG and risk of lung cancer as well as potential interaction with the OGG1 Ser326Cys polymorphism in a population-based cohort of 25 717 men and 27 972 women aged 50-64 years with 3-7 years follow-up. We included 260 cases with lung cancer and a sub-cohort of 263 individuals matched on sex, age and smoking duration for comparison. Urine collected at entry was analysed for 8-oxodG by HPLC with electrochemical detection. The excretion of 8-oxodG was higher in current smokers, whereas OGG1 genotype had no effect. Overall the incidence rate ratio (IRR) (95% confidence interval) of lung cancer was 0.99 (0.80-1.22) per doubling of 8-oxodG excretion and there was no interaction with OGG1 genotype. However, among never-smokers (eight cases and eight sub-cohort members) the IRR was 11.8 (1.21-115) per doubling of 8-oxodG excretion. The association between 8-oxodG excretion and lung cancer risk among never-smokers suggests that oxidative damage to DNA nucleotides is important in this group.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1993

Cortisol production rate and the urinary excretion of 17-hydroxycorticosteroids, free cortisol, and 6 beta-hydroxycortisol in healthy elderly men and women.

BACKGROUND: Although many workers have tested adrenal function in the elderly, few have studied the effect of aging on cortisol production rate or urinary free cortisol or 6 beta-hydroxycortisol excretion, and none have published comparisons of these variables between old people of defined health status and young people. METHODS: We have measured cortisol production rate and the urinary excretion of free cortisol, 6 beta-hydroxycortisol, 17-hydroxycorticosteroids (Porter-Silber chromogens) and creatinine in elderly men and women screened by the SENIEUR protocol and in young men; 17-hydroxycorticosteroid and 6 beta-hydroxycortisol excretion were also measured in young women. The period of measurement was 24 h or, usually, 48 h. RESULTS: Only 6 beta-hydroxycortisol excretion was affected by aging; it was lower in the elderly men and women than in their younger counterparts. Urinary free cortisol excretion was lower in the elderly women than in the elderly men. There were no significant differences between groups in cortisol production rate or 17-hydroxycorticosteroid excretion. Excretion and (over the first 24 h) clearance of creatinine were lower in the old women than in the old men. The cortisol-related variables tended to be positively correlated with each other and with the relevant creatinine-related variables in the elderly subjects; over the first but not the second 24 h, most of the correlations were significant in the men and women combined. CONCLUSIONS: With the exception of 6 beta-hydroxycortisol, the data agree with measurements of plasma cortisol and the results of adrenal function tests in showing little change in hypothalamic-pituitary-adrenal function with aging in healthy people.

17-Hydroxycorticosteroids↗
PubMed1979

Excretion pathways of amphotericin B.

The role of the biliary system in excretion of amphotericin B was explored in a dog model that allowed either external diversion of all bile or complete biliary obstruction. In dogs with biliary diversion, which were given a single dose of amphotericin B intravenously, excretion of amphotericin B in the bile lasted for seven to 10 days and accounted for only 3% +/- 2% (mean +/- SD) of the dose, whereas excretion in the urine was prolonged (23--35 days) and greater (21% +/- 5% of the dose); the stool contained no amphotericin B. However, bile salt depletion may have depressed biliary excretion of amphotericin B: in a dog with an intact biliary system, 19% of the dose was excreted in the stool over 11 days. In dogs given amphotericin B daily, serum levels were 19% +/- 3% higher during periods of biliary obstruction than during periods of free bile flow (P less than 0.05). Thus, excretion of amphotericin B in the bile (less than or equal to 19% of the dose) and in the urine (21% of the dose) accounted for a minority of total drug clearance. Nevertheless, prolonged excretion of amphotericin B by these routes after a single dose suggests that infrequent doses of amphotericin B may provide effective treatment for certain forms of fungal infection.

Amphotericin B↗
PubMed1983

Study of alanine aminopeptidase excretion as a test of gentamicin nephrotoxicity.

We studied the urinary excretion of the proximal tubular enzyme alanine aminopeptidase (AAP) by 38 patients who received gentamicin and by 45 similar control patients. AAP excretion by the control patients was highly variable. The pattern of AAP excretion distinguished patients with pre-renal and renal causes for increases in serum creatinine (SCr) but this can be done more simply with the urine to serum creatinine ratio. Peak AAP excretion did not reflect renal damage in oliguric patients and di not identify gentamicin patients with a renal cause for increases in SCr. The level of AAP excretion in the first three days of gentamicin treatment did identify the three patients with renal causes for an increase in SCr and was highest in a patient with symptomatic hypomagnesaemia due to impairment of proximal tubular function. We concluded that study of AAP excretion in normal volunteers receiving three-day courses of aminoglycosides is a valid screening test for nephrotoxicity but that AAP excretion is too non-specific to use in clinical practice.

Aminopeptidases↗
PubMed1990

The effect of obstruction on the biliary excretion of cefoperazone and ceftazidime.

The biliary excretion of cefoperazone and ceftazidime was studied by endoscopic cannulation of the common bile duct, in patients with complete biliary obstruction and in an unobstructed control group. Patients were given each drug prophylactically for 24 h before endoscopy and as a single dose at the time of cannulation. In unobstructed patients biliary excretion of ceftazidime was passive. At the time of cannulation bile contained 10% of the peak serum concentration, rising to 20% 90 min later. Cefoperazone excretion was active. At cannulation biliary concentrations were 200% of the serum peak, 900% at 60 min and 700% at 90 min. In obstructed patients, bile sampled immediately at decompression contained neither antibiotic. Passive excretion of both drugs occurred rapidly after relief of obstruction and biliary concentrations were 20% of maximum serum levels at 60 min. Twenty-four hours later passive excretion had further improved, but the active excretion mechanism of cefoperazone had still not recovered. We conclude that obstruction impairs active as well as passive biliary excretion of antibiotics, that drainage is essential for the control of sepsis in obstructed cholangitis, and that both cefoperazone and ceftazidime achieve similar and therapeutic concentrations in bile during the 24 h after decompression.

Adult↗
PubMed1989

Differential changes in the urinary excretion of two orally administered polyethylene glycol markers (PEG 900 and PEG 4000) in rats after feeding various carbohydrate gelling agents.

The urinary excretion of two orally administered polyethylene glycol markers (PEG 900 and PEG 4000) was measured in rats after feeding various carbohydrate gelling agents. Pectin, guaran, methylcellulose, and carrageenan were added (20% wt/wt) to a fiber-free control diet and were fed for 4 wk prior to the experiment. Excretion of 3H-PEG 900 and 14C-PEG 4000 was measured over a period of 96 h after administration of the markers in the drinking water. In general, the ratio of PEG 4000 to PEG 900 in the urine increased after fiber feeding: from 0.20 in the controls to 0.31, 0.37, 0.29, or 0.27 (medians) in the pectin-, guaran-, methylcellulose-, or carrageenan-fed group, respectively. The pattern of excretion of the two PEG markers in rats fed the fiber-free diet differed from that in the polysaccharide-fed rats. Pectin and guaran, two polysaccharides readily fermented by intestinal bacteria, led to a higher excretion of PEG 4000 but an unaltered excretion of PEG 900, whereas methylcellulose and carrageenan, two polysaccharides more inert against microbial degradation, were associated with a lower excretion of PEG 900 with unchanged excretion of PEG 4000. The study shows that polysaccharides, which may be representative of the soluble portion of dietary fiber, can influence the intestinal permeability of larger molecules. The microbiologically degradable polysaccharides in particular may lead to an increased absorption of larger molecules.

Animals↗
PubMed1995

Starch and dietary fiber components are excreted and degraded to variable extents in ileostomy subjects consuming mixed diets with wheat- or oat-bran bread.

The study was conducted to determine if the excretion of starch and dietary fiber components varies in ileostomy subjects consuming diets high or low in dietary fiber. Excretion of starch, enzyme-resistant starch and dietary fiber components was studied in nine human subjects with ileostomies, who consumed (in a crossover design) a wheat bread-based diet (daily intake 274 g starch, 2.4 g enzyme-resistant starch and 14.4 g total dietary fiber) and a high fiber diet based on oat-bran bread (daily intake 243 g starch, 2.7 g enzyme-resistant starch and 40.2 g total dietary fiber). Food and excreta were collected on d 3 and 17. No significant differences in excretion of starch, enzyme-resistant starch or dietary fiber components were found on these 2 d in each dietary period. When subjects consumed the wheat bread-based diet they excreted (mean +/- SD) 3.3 +/- 1.7 g starch and 2.4 +/- 0.4 g enzyme-resistant starch daily, whereas when consuming the oat bran-based diet they excreted 4.5 +/- 3.1 g starch and 2.5 +/- 0.4 g enzyme-resistant starch. During both dietary periods subjects excreted significantly greater amounts of certain dietary fiber polysaccharide residues (fucose, galactose and uronic acid) than they ingested. This indicates a contribution of endogenous and/or microbial material to the dietary fiber value in ileostomy effluents. However, significantly less excretion of some dietary fiber polysaccharide residues, especially glucose residues, during the oat-bran bread-based dietary period was also noted. This was presumably caused by a degradation of mixed-linked (1,3),(1,4)-beta-D-glucans.

Adult↗
PubMed2003

Hydroxytyrosol excretion differs between rats and humans and depends on the vehicle of administration.

Interest in the in vivo biological activities of olive oil phenolics is rapidly growing, and different models and vehicles of administration are used worldwide. Matters of practicality determine the use of rats rather than humans as the model of choice. Also, growing interest in nutraceuticals is leading to the formulation of compounds containing olive oil phenols. In this study, we compared metabolism and urinary excretion of hydroxytyrosol [(HT), the most representative phenol of olive oil] between rats and humans by evaluating excretion of HT and its major metabolite, homovanillyl alcohol. Also, we compared human excretion of HT when consumed as a natural component of extra virgin olive oil, when added to refined olive oil, or when added to yogurt (as an approximation of functional food). Urinary excretion of HT was greater in humans than in rats, a species with a high basal excretion of HT and its metabolites. The high (234% of HT administered) excretion of free HT suggests that hydrolysis of oleuropein administered in humans (still an unresolved issue) occurs in vivo. Moreover, human HT excretion was much higher after its administration as a natural component of olive oil (44.2% of HT administered) than after its addition to refined olive oil (23% of HT administered) or yogurt (5.8% of dose or approximately 13% of that recorded after virgin olive oil intake). These data suggest that the rat is not the appropriate model for the study of HT metabolism and that HT-containing functional foods should be carefully formulated.

Animals↗
PubMed1993

Agreement between overnight and 24-hour urinary cation excretions in southern Chinese men.

Agreement between overnight and 24-hour urinary sodium, potassium, calcium, and magnesium excretion was studied in a sample of 63 normotensive Southwestern Chinese men: 30 Yi farmers and 33 urban residents in April 1989. Overnight (8-hour) and 24-hour urine specimens were collected on 3 consecutive days. Estimated correlation coefficients between 24-hour and overnight mean true values were 0.863 and 0.906 for sodium, 0.736 and 0.816 for potassium, 0.902 and 0.725 for calcium, and 0.733 and 0.703 for magnesium in Yi farmers and urban residents, respectively. Hourly overnight urinary sodium and potassium excretion rates were significantly lower than the corresponding hourly 24-hour urinary excretion rates: -0.60 and -1.99 mmol/hour for sodium, -1.24 and -0.48 mmol/hour for potassium (all p < 0.05) in Yi farmers and urban residents, respectively. In multiple regression analyses, the differences between 24-hour and overnight urinary sodium and potassium excretion rates were significantly and positively related to differences between 24-hour and overnight creatinine excretion rates. The ratios of intraindividual to interindividual variance were lower for 24-hour collections than for overnight collections for sodium and calcium, but the differences in these ratios for potassium and magnesium were small. For sodium and calcium, twice as many overnight as 24-hour collections were required to estimate the correlation between cations and blood pressure with the same accuracy; for potassium and magnesium, overnight and 24-hour collections were equally accurate. These results indicate that in normotensive populations such as the one studied, overnight urine collections may be used to estimate 24-hour cation excretion. The underestimate of cation excretion by assessments based on collection of overnight specimens may be due to either a lower creatinine clearance or a lower intake of cations at night.

Adult↗