SEARCH · Search PubMed

Results for “URINE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1999

Comparison of urine anion gap, urine osmolal gap and modified urine osmolal gap in assessing the urine ammonium in metabolic acidosis.

Twenty-four hour urine and spot urine samples from 29 patients with metabolic acidosis were collected for evaluation of urine ammonium in relation to urine anion gap, urine osmolal gap (OG) and modified urine osmolal gap (MOG). Their underlying diseases included SLE in 8, RTA in 7, CRF in 6, RPGN in 2 (one with SLE), Lowe syndrome in 2, on acetazolamide in 2, gastroenteritis in 2, and CAH in one. Twenty-three patients had normal serum anion gap (< 14 mmol/L). Their mean CO2 was 13.77 (9.4-17.9) mmol/L, net acid excretion (NAE) was 33.18 +/- 35.36 mmol/24 hour, NH+4 excretion was 29.16 +/- 31.97 mmol/24 hour. Neither the 24-hour urine nor spot urine anion gap correlated with corresponding urine NH+4 with or without adding urine HCO-3 in the calculation. Spot urine NH+4 correlated well with urine OG (r2 = 0.82, p < 0.001) and less with MOG (r2 = 0.339, p < 0.006). The urine osmolality was well correlated with the sum of 2 (Na+ + K+ + NH+4) + urea for both spot (r2 = 0.990, p < 0.001) and 24 hour urine (r2 = 0.907, p < 0.001) collection. Twenty-four hour urine NH+4 did not correlate with the OG or the MOG. There was no correlation between spot urine NH4/Cr ratio and 24 hour urine NH4/Cr ratio (r2 = 0.243, p = 0.53) nor between spot NAE/Cr ratio and 24 hour urine NAE/Cr ratio (r2 = 0.380, p = 0.014). Therefore in the presence of low urine NH+4 (< 100 mmol/L), urine osmolal gap may be used to determine urine NH+4 indirectly with good correlation. Twenty-four hour urine collection is still necessary to assess renal acidification.

Acid-Base Equilibrium↗

PubMed1996

Evaluation of urine acidification by urine anion gap and urine osmolal gap in chronic metabolic acidosis.

To investigate the clinical significance of urine anion gap and urine osmolal gap as indirect markers of urine acidification in chronic metabolic acidosis, we evaluated urine ammonium (NH4+), net acid excretion (NAE), urine anion gap (Na(+) + K(+) - Cl-), and urine osmolal gap (urine osmolality - [2(Na(+) + K(+)) + urea]) in 24 patients with chronic renal failure (CRF), eight patients with classic distal renal tubular acidosis (dRTA), and eight NH4Cl-loaded normal controls (NCs). Urine NH4+ excretion was lower (P < 0.001) in the CRF (5.4 +/- 0.6 mmol/d) and dRTA (19.2 +/- 2.7 mmol/d) patients than in the NCs (52.6 +/- 3.7 mmol/d); NAE was also lower (P < 0.001) in the CRF (9.8 +/- 1.6 mmol/d) and dRTA (16.7 +/- 4.7 mmol/d) patients than in the NCs (79.4 +/- 4.7 mmol/d). Urine anion gap was higher (P < 0.001) in the CRF (24.7 +/- 2.2 mmol/L) and dRTA (36.7 +/- 7.7 mmol/L) patients than in the NCs (-16.2 +/- 5.5 mmol/L). Urine osmolal gap was lower (P < 0.05) in the dRTA patients (129.7 +/- 17.0 mmol/L) than in the NCs (319.7 +/- 58.4 mmol/L). When the data from all subjects were pooled, urine anion gap correlated inversely with urine NH4+ (r = -0.70, P < 0.001) and with NAE (r = -0.83, P < 0.001), and urine osmolal gap correlated positively with urine NH4+ (r = 0.69, P < 0.01) and with NAE (r = 0.71, P < 0.05). We conclude that impaired urine acidification in CRF and dRTA patients is associated with an increase in urine anion gap and a decrease in urine osmolal gap, and that both urine anion gap and urine osmolal gap correlate well with NAE as well as with urine NH4+.

Acid-Base Equilibrium↗

PubMed1979

Idiopathic calcium nephrolithiasis. 1. Differences in urine crystalloids, urine saturation with brushite and urine inhibitors of calcification between persons with and persons without recurrent kidney stone formation.

The propensity of urine to promote calcium stone formation was compared in 64 patients with recurrent idiopathic calcium nephrolithiasis and 30 healthy individuals without such a history. The rates of excretion of urine crystalloids, the urine saturation with brushite (CaHPO4-2H2O), the ability of the urine to calcify collagen in vitro, and the concentration of urine inhibitors of collagen calcification were measured. The patients had a reduced urine citrate excretion rate in addition to an increased urine calcium excretion rate, while the rates for urine magnesium, phosphate, uric acid and oxalate were not significantly different in the two groups of subjects. The urine concentration of magnesium, phosphate and uric acid was decreased in the patients because of the higher urine volume. The urine creatinine excretion rate correlated with the rates of excretion of urine calcium, magnesium, phosphate, uric acid and oxalate in both groups, which suggested that increased lean body mass, possibly associated with greater food intake, may be an important determinant of crystalloid excretion. The urine of the patients was significantly more saturated with brushite than the urine of the control subjects and resulted in greater collagen calcification when incubated in vitro. The urine concentration of inhibitors of collagen calcification, however, was not significantly different in the two groups. Thus, the urine of patients with recurrent idiopathic calcium nephrolithiasis is more highly saturated with brushite, largely as a result of an increased urine calcium excretion rate, and contains a lower concentration of magnesium and citrate, substances that tend to prevent the precipitation and growth of crystals in urine.

Adult↗

PubMed2000

Urine calcium and urine sodium concentrations are not related, after adjustment for urine magnesium.

BACKGROUND AND OBJECTIVES: Urine calcium correlates with urine sodium. The aims of this study were to investigate whether the urine sodium-calcium relationship persists into old age and whether it holds after adjustment for urine magnesium. DESIGN: Cross-sectional descriptive analysis. PATIENTS: Residents of two aged care institutions (median age 84 years) who were not taking diuretics, calcium or vitamin D supplements. MEASUREMENTS: Early morning urine calcium, sodium and magnesium, plasma creatinine and serum 25-hydroxyvitamin D and parathyroid hormone. RESULTS: Urine calcium correlated with urine sodium (r = 0.29, P < 0.01) and with urine magnesium (r = 0.56, P < 0.001). After adjustment for urine magnesium, the relationship between urine sodium and urine calcium was no longer significant. Forty-five percent of the interindividual variation in urine calcium was explained by a linear model on the basis of urine magnesium and plasma creatinine. CONCLUSION: The data indicate that a correlation between urine sodium and calcium persists in very old age. However, this correlation no longer holds after adjustment for urine magnesium. Further studies examining urine calcium excretion should also consider urine magnesium.

25-Hydroxyvitamin D 2↗

PubMed1991

Comparison between spot urine and overnight urine in the estimation of 24-hour excretion of urine protein, sodium and kallikrein.

To compare the value of spot urine and overnight 9-hour urine in the estimation of 24-hour urinary sodium excretion (UNaV), protein excretion (UpV) and kallikrein excretion (UKaV), we measured the concentration of sodium, protein, kallikrein and creatinine in spot urine, overnight 9-hour urine, and 24-hour urine samples obtained from 21 patients with various renal diseases. They ranged in age from 16 to 75 years with 10 males and 11 females. Urinary protein was measured by the Coomassie Blue dye-binding method. Urinary kallikrein activity was measured by assay of its amidase activity on synthetic substrate S-2266. The results showed that the 9-hour UpV and 9-hour urine P/Cr ratio was better correlated with the 24-hour UpV than the spot urine P/Cr ratio (at 9-11 AM), and the 9-hour UKaV and spot urine Ka/Cr ratio were better correlated with the 24-hour UKaV than the 9-hour Ka/Cr ratio. Only the 9-hour UNaV was correlated with the 24-hour UNaV. We conclude that overnight 9-hour urine, in view of its lower cost, equal effectiveness and convenience, is the best method to substitute for 24-hour urine collection in the evaluation of Na, P and Ka excretion in patients with renal diseases.

Adolescent↗

PubMed1975

Comparison of costs for testing a wide variety of drugs of abuse per urine specimen in a drug abuse urine screening program and frequent urine collections.

Existing urine testing techniques in a drug abuse urine screening program with their capacity to analyze urine specimens per day are discussed. The start-up cost using each technique and cost per specimen are presented. A single step extraction technique using ion-exchange paper to absorb drugs prior to thin-layer chromatography (TLC) as reported by these laboratories will cost $0.58 per specimen, for testing the entire aray of drugs of abuse (at least 9-14 tests per specimen). Sensitivity reported using TLC technique for the morphine base is 0.15 mug/ml (minimum volume of urine needed 20 ml), 0.10 mug/ml if the volume of urine available is 30-35 ml, and 0.07 mug/ml if the volume of urine available is 43-50 ml.

Chromatography, Gas↗

PubMed2001

Crystallisation properties in stone forming and normal subjects' urine diluted using a standardised procedure to match the composition of urine in the distal part of the distal tubule and the middle part of the collecting duct.

Using a standardised procedure, we assessed the crystallisation properties of calcium phosphate in urine with a composition matching that in the distal part of the distal tubules (DTd) and of calcium oxalate in urine with a composition matching that in the mid-collecting duct (CDm). We used 8-h urine samples collected between 2200 h and 0600 h with sodium azide as preservative. Urine from ten patients with recurrent CaOx stone formation and from ten normal subjects was used for the measurements. The DTd and CDm samples were obtained by diluting the voided 8-h urine to 3000 ml and 1750 ml per 1.73 m2 body surface area, respectively. The nucleation was studied in DTd urine following supersaturation with CaP. The crystal size distribution was assessed with a Coulter counter both following supersaturation of DTd urine with CaP and of CDm urine with CaOx. The crystallisation of CaP in DTd urine as well as that of CaOx in CDm urine, in the presence of CaP crystals that had been precipitated in DTd urine, was measured with the isotope technique. The inhibition of CaOx and brushite crystal aggregation in standardised diluted aliquots of DTd and CDm urine was assessed spectrophotometrically as the rate of sedimentation. There was a slightly increased sedimentation rate and a lower initial absorbance in DTd urine from stone formers supersaturated with CaP. Although these findings might reflect a state of increased crystal aggregation in stone formers' urine, this could not be confirmed by crystal size measurements in the Coulter counter. The inhibition of brushite crystal aggregation in DTd urine was significantly in stone formers' urine than in normal subjects' urine (P < 0.001). Moreover, all inhibition values in DTd samples from stone formers were negative, suggesting a promoter effect on crystal aggregation. The inhibition of CaOx crystal aggregation in CDm urine also was significantly higher in CDm urine from normal subjects than in CDm urine from stone formers (P < 0.05). For all other variables the level was similar when urine samples from the two groups were compared. Although this series of crystallisation assessments was carried out on a small number of standardised diluted urine samples only, the results nevertheless emphasise a defect in aggregation inhibition as one important determinant for an abnormal calcium salt crystallisation in patients with recurrent stone formations. This difference obviously includes aggregation of both CaP crystals in DTd urine and CaOx crystals in CDm urine. The results also show that assessment of crystallisation properties of this kind can be carried out in standardised, diluted 8-h night urine samples, which accordingly can be used in the routine work-up of patients with calcium stone disease. Such an approach might prove useful in order to get information on the combined effects of the driving force of supersaturation and crystallisation modifying properties accomplished by urinary macromolecules and other modifying agents.

Crystallization↗

PubMed1991

Relationship between urine ammonium ion excretion and urine anion gap in dogs.

Acidemia stimulates renal ammonia production and excretion. This adaptive response allows increased H+ secretion and generation of new bicarbonate. To determine whether a relationship existed between urine ammonium (NH4+) concentration and excretion and urine anion gap (Na+ + K(+)- Cl-), ammonium chloride (NH4Cl) was administered per OS for 5 days to induce systemic acidemia in 12 healthy Beagles. During NH4Cl administration, a strong, statistically significant (P less than 0.0001) relationship was apparent between urine NH4+ concentration measured in millimoles per liter and urine anion gap. Regression equation: urine [NH4+] = 8.2 - 0.416 x urine anion gap; r = -0.897. A statistically significant (P = 0.0001) relationship existed between urine NH4+ excretion measured in millimoles per kilogram of body weight per day and urine anion gap. Regression equation: urine NH4+ excretion = 0.74 - 0.38 x urine anion gap; r = -0.768. As urine NH4+ concentration or excretion increased, urine anion gap became more negative. Before NH4Cl administration (no systemic acidemia), a weak, but statistically significant (P = 0.015) relationship was observed between urine NH4+ concentration and urine anion gap. Regression equation: urine [NH4+] = 65.2 - 0.141 x urine anion gap; r = -0.41. However, a relationship was not evident between urine NH4+ excretion and urine anion gap before NH4Cl administration. Hence, urine anion gap is a reliable index of urine NH4+ concentration and excretion only in dogs with metabolic acidosis. In human beings with distal renal tubular acidosis, NH4+ excretion is inappropriately low and results in a positive urine anion gap.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗

PubMed1990

A modification of the urine osmolal gap: an improved method for estimating urine ammonium.

A modification of the urine osmolal gap was evaluated as an estimate of urine [NH4+]. We proposed that: Urine [NH4+] = Urine osmolality - [2(Na+ + K+) + urea + glucose]/2 Spot urine samples were collected from normal volunteers and from individuals with ketonuria; the modified urine osmolal gap as well as two other previously described estimates of urine [NH4+] were compared with measured urine [NH4+]. There was a significant positive linear correlation between the urine [NH4+] and the modified urine osmolal gap in normal volunteers (r = 0.81; p less than 0.01) and in individuals with ketonuria (r = 0.93; p less than 0.001). The originally described urine osmolal gap greatly overestimated the urine [NH4+] but also showed a significant correlation. The urine anion gap was not a valid estimate of urine [NH4+] within the range of values measured in our subjects. The modified urine osmolal gap is an improvement over previously described estimates of urine [NH4+] and can be used as a single calculation in place of the other two.

Acid-Base Equilibrium↗

PubMed1999

Evaluation of detection techniques and laboratory proficiency in testing for drugs of abuse in urine: an external quality assessment scheme using clinically realistic urine samples. Steering Committee for the United Kingdom National External Quality Assessment Scheme for Drugs of Abuse in Urine.

Techniques for the detection of drugs of abuse were compared using data from 43 urine samples distributed by the United Kingdom National External Quality Assessment Scheme. Drug mixtures simulated clinical specimens and contained drugs at the following median concentrations: amphetamine 1.6 mg/L (six samples), barbiturates 1.7 mg/L (six samples), benzoylecgonine 0.6 mg/L (eight samples), benzodiazepines 1.6 mg/L (four samples), cannabinoids 59 micrograms/L (four samples), methadone 1.7 mg/L (11 samples) and morphine 1.7 mg/L (seven samples). Significant lack of sensitivity was demonstrated for one or more analytes by all chromatographic techniques, including gas chromatography with mass spectrometry. Commercial immunoassay kits exhibited higher sensitivity, though some assays performed significantly less well than others. Significant non-specificity was also a greater problem for chromatographic techniques compared with immunoassays in samples containing therapeutic agents not structurally related to abused compounds. In the presence of therapeutic interferents structurally related to the test compounds, false positive reports for illicit materials increased from < 1% to > 6%. Use of confirmatory tests significantly reduced the incidence of both false negative and false positive reports.

Evaluation Studies as Topic↗

PubMed1992

The influence of pH and urine composition on urease enzymatic activity in human urine.

It is reasonable to assume that the rate of pH increase in urine induced by urease-producing microorganisms is one of the factors which determine whether crystallisation with subsequent stone formation will occur or not. To evaluate how the time needed to increase urine pH varies between different urine samples and how it depends on urine composition, a standardised amount of urease was added to different human urine samples. The incubations were performed in a pH-stat. This allowed simultaneous study of how urease enzymatic activity depends on urine pH and how it varies between different urines. The enzymatic activity was found to be negatively correlated to urine pH and to vary between different urines. The rate of the pH increase varied markedly between different urines. Small pH increases depended on the native urine pH and urease enzymatic activity. Higher pH increases up to the levels of phosphate crystallisation depended more on urine phosphate, the major urine buffer. The results presented show that urine composition influences the urease-induced pH increase. This might have clinical implications.

Adult↗

PubMed2001

Determination of NTx in second-morning urine: a proposal for the standardization of morning urine collection.

UNLABELLED: According to the instruction manual from the producer of kits for determining the levels of aminoterminal telopeptide of type I collagen of organic bone matrix (NTx), the time of the collection of second-morning urine is arbitrary, i.e., a patient can urinate anytime within the period from about 6 to 8:30 a.m. This time interval is within the period of change in the circadian rhythm of the NTx excretion (maximum excretion with transition into fast decrease of excretion). Therefore, we considered it appropriate to standardize the conditions for the collection of second-morning urine and proposed applying the so-called 2-hour morning urine NTx2 (from 6 to 8.00 a.m. after an overnight fast). We examined 48 female patients aged 33-65 years with primary or secondary osteopenia or osteoporosis (all patients had normal renal functions). In these patients we determined NTx (Osteomark, OSTEX, USA) in standardly used 24-hour urine (NTx24) and in the proposed 2-hour morning urine (NTx2). AIM OF THE STUDY: 1) To find a mathematical character for the dependence of values of dependent variable NTx2 on independent variable NTx24 and to evaluate the statistical significance of this dependence; 2) to compare the ratio of the widths of 95% confidence intervals (C. I.) for NTx2 and NTx24 in patients (index: IO) with the ratio of the widths of reference limits for NTx in arbitrary second-morning urine (NTx2ostex) and in 24-hour urine (NTx24ostex) in healthy women (index: IR); 3) to evaluate the proposed 2-hour urine for the determination of NTx. STATISTICAL ANALYSIS: Stochastic and deterministic linear regressive analysis. Index of 95% C. I., index of reference limits. RESULTS: A statistically significant (P < 0.01) regressive dependence (r2 = 0.781) was found between the values of NTx24 and NTx2. The index for the widths of reference limits (IR) was 1.5 times greater than the index for osteopenic and osteoporotic patients (IO), meaning that the scatter of the NTx2ostex values was greater than NTx2 in the proposed 2-hour urine. CONCLUSION: Based on the statistically significant linear regressive dependence between NTx24 and NTx2 values, it is possible to use the proposed 2-hour morning urine to determine NTx levels in women. The introduction of 2-hour morning urine NTx2 could decrease the fluctuation range of NTx values in repeated examinations and in comparison with the determination of NTx2ostex in a random second-morning urine sample could make its values more accurate.

Adult↗

PubMed1986

Urine beta-thromboglobulin concentration or beta-thromboglobulin/creatinine ratio in single voided urine samples cannot be reliably used to estimate quantitative beta-thromboglobulin excretion.

Different procedures are currently used in the urine beta-thromboglobulin (BTG) assay. We investigated the reliability of limited urine collections and of different expressions of urine BTG results (concentration, urine BTG/creatinine ratio) for the measurement of hourly or daily BTG excretion rates. BTG was measured by a sensitive RIA method in various urine collections of normal subjects (n.80) and patients (n.120) with miscellaneous diseases where an enhanced in-vivo platelet activation could be expected. The BTG concentration in a 6-hour urine collection appeared to change in relation to the urine flow rate (r = -0.53 in normals, r = 0.27 in patients, p less than 0.01) and urine osmolality (r = 0.46 in normals, r = 0.31 in patients, p less than 0.01). In both normals and patients not a very good correlation was observed between the urine BTG/creatinine ratio and the BTG excretion rate (r = 0.54 and r = 0.48; p less than 0.001, respectively). Variable coefficients of correlation (r = 0.83-0.34) were observed between the BTG excretion rate of single voidings of the morning, afternoon-evening and night and the daily BTG excretion both in normals and patients. Reliable measurements of the BTG in urine should be expressed as the hourly excretion rate in a given period of the day for limited urine collections or as the daily excretion for 24-hour urine collections.

Beta-Globulins↗

PubMed2003

Feasibility of using paper impregnated with urine instead of liquid urine for assessing ovarian activity.

BACKGROUND: Ovarian activity should ideally be assessed by serial non-invasive methods that require simple procedures for sample collection and storage. Measurement of urinary oestrone-3-glucuronide and pregnanediol-3 alpha-glucuronide is a non-invasive method available for assessment of ovarian activity, but transport of large numbers of urine samples is cumbersome and samples need to be stored frozen. An alternative sample collection, transport and storage procedure that is easier to handle and requires no or minimal cold storage facilities will particularly benefit studies in which ovulatory activity needs to be assessed in field settings. OBJECTIVE: To evaluate the feasibility of using paper impregnated with urine as an alternative to liquid urine for the measurement of oestrone-3-glucuronide and pregnanediol-3 alpha-glucuronide concentrations in the assessment of ovarian activity. METHODS: Urine samples collected daily throughout regular menstrual cycles were stored as liquid urine at -20 degrees C, and as paper impregnated with urine, in the refrigerator for 3 to 12 months or at room temperature for 1 to 6 months. Oestrone-3-glucuronide and pregnanediol-3 alpha-glucuronide concentrations were measured in these urine samples by enzyme immunoassay. Values obtained were correlated using Spearman's correlation test. RESULTS: The pattern of oestrone-3 glucuronide and pregnanediol-3 alpha-glucuronide concentrations estimated using paper impregnated with urine followed that of liquid urine in all storage conditions used. Values obtained by two methods correlated significantly (p < 0.001 to 0.0001) though the paper impregnated with urine gave slightly higher values. CONCLUSIONS: Paper impregnated with urine can be used to facilitate sample collection, transport and storage of urine when oestrone-3-glucuronide and pregnanediol-3 alpha-glucuronide measurements are required in a large number of serial samples to assess ovarian activity.

Estrone↗

PubMed1991

Microbial stabilization of antibiotic-containing urine samples by using the FLORA-STAT urine transport system.

The FLORA-STAT Urine Transport System (Wadley Biosciences Corp./Lymphokine Partners Ltd., Dallas, Tex.) was evaluated for its efficacy in maintaining organism count and in effectively blocking the bactericidal action of therapeutic antimicrobial agents in urine samples when the urine samples were held at room temperature. Reconstructions with 53 organism-antimicrobial combinations were performed at 0, 4, 8, and 24 h in which the FLORA-STAT system was compared with two boric acid-based systems (Urine C&S Transport Kit [Becton Dickinson VACUTAINER Systems, Rutherford, N.J.]; Sage Urine Collection Kit for Culture [Sage Products, Inc., Cary, Ill.]) and untreated urine. At 24 h, less than 1-log-unit changes in organism counts were found in 100, 92, and 10% of the urine samples without antimicrobial agents and in 97, 65, and 16% of the urine samples with antimicrobial agents for FLORA-STAT-treated, boric acid-treated, and untreated urine samples, respectively. The FLORA-STAT system was further evaluated by sending split samples prepared from laboratory-inoculated patient urine samples (57 without and 50 with antimicrobial agents) to four commercial laboratories by using their respective transport devices and procedures. Samples were also sent to a local reference laboratory which provided prompt processing. Each laboratory received independently labeled transport devices containing untreated, FLORA-STAT-treated, and preservative-treated (if provided by the commercial laboratory) samples prepared from the same urine specimen of a patient. Average estimated transport times ranged from 13 to 24 h for the commercial laboratories; the transport time was less than 4 h for the local reference laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1986

Urine pH and the relationship between urine flow and urinary prostaglandin E excretion in the rat.

The relationship between urine flow and urinary prostaglandin E (PGE) excretion was investigated at constant urine pH in the anaesthetized rat. The urine pH was maintained at approximately pH 6 or pH 8 by the intravenous infusion of either ammonium chloride or sodium bicarbonate respectively. Two distinct patterns in the relationship between PGE excretion and urine flow were observed. The first showed a fall in urinary PGE excretion as the urine flow increased over the low flow range of 2-5 ml/h, and was common to both experiments. The second relationship, however, showed a marked difference between the ammonium chloride and sodium bicarbonate experiments since: (a) in acidic urine (pH 6), PGE excretion increased (P less than 0.002) with the urine flow, attaining a rate of 87 +/- 6 pmol/h (n = 6) at the highest level of flow achieved (12 ml/h); (b) in alkaline urine (pH 8), PGE excretion was significantly (P less than 0.01) higher but did not increase with urine flow, remaining constant at approximately 90 pmol/h (n = 6). The lack of any additive effect on urinary PGE excretion between increasing the urine flow and making the urine alkaline may be explained by both stimuli acting through a common mechanism, a concept which is consistent with the hypothesis that PGE may be reabsorbed in the distal nephron. The flow-dependency of urinary PGE excretion could therefore result from a reduction in reabsorption rather than the increase in passive secretion proposed previously.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1996

[Can examination of spontaneous urine samples adequately replace 24-hour-urine samples for determining excretory rate of various lithogenic and inhibitory substances in metabolic evaluation of kidney calculi patients?].

The gold standard for metabolic evaluation of stone-forming patients is the 24-h urine specimen. Recently, some authors have suggested that for routine metabolic evaluation spot urine samples are as valuable as the 24-h urine specimen. The purpose of our study, was to determine the value of the spot urine sample in comparison with the 24-h urine specimens. Eighty-eight healthy volunteers on different diets were investigated (32 vegetarians, 12 body-builders without protein concentrates, 28 body-builders on protein concentrates, and 16 subjects on a regular European diet). Using 24-h specimens, excretion rates of oxalate, calcium, sodium and potassium were determined. The concentration ratio of these electrolytes to creatinine was calculated for spot urine samples. A highly significant correlation between the excretion rates and the results of the spot urine samples was found for all parameters. However, the correlations showed considerable variations. On the other hand, we were able to show that creatinine excretion is highly dependent on daily protein intake, body weight and glomerular filtration rate. This leads to a considerable inter- and intraindividual variation in creatinine excretion. This variation of the creatinine excretion is the major cause for the variation in the results of spot urine samples. It is concluded that spot urine samples are an inadequate substitute for the 24-h urine specimen and that the 24-h urine specimen is still the basis for metabolic evaluation in stone patients.

Adolescent↗

PubMed1997

Urine samples from disposable diapers: an accurate method for urine cultures.

BACKGROUND: The method of collection of the urine sample is of paramount importance in making a diagnosis of urinary tract infection in infants and children. Squeezing urine out of disposable diapers can provide a urine sample that can be used to detect chemical abnormalities as well as a specimen suitable for microscopic examination. To date there have been no reported studies on the use of this technique for urine culture as compared with samples collected by suprapubic aspiration and catheterization. METHODS: Urine was obtained from 38 infants aged under 2 years who presented with fever with no obvious cause. All infants had urine collected either by catheterization or suprapubic aspiration and by extraction from a disposable diaper. The urine samples were cultured using standard bacteriologic techniques. RESULTS: Five infants had a urinary tract infection, as shown by a pure growth of more than 10(5) colonies/mL of a single species of bacterium. In all the cases the same result was obtained from both the diaper urine sample and the sample obtained by suprapubic aspiration or catheter. In 31 infants the urine samples collected by both techniques (diaper and catheter or suprapubic aspiration) were negative, and in only 2 infants did the diaper specimen yield a positive result, while the urine obtained by suprapubic aspiration or catheter was sterile. CONCLUSIONS: Urine obtained from a disposable diaper can provide a valid sample for diagnosing urinary tract infection. The technique is simple, and can be carried out readily in ambulatory settings with minimal equipment and expense.

Disposable Equipment↗