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Results for “SPECIFIC GRAVITY”

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PubMed1984

Reduction of brain specific gravity in mice prenatally exposed to trichloroethylene.

The specific gravity of the brain is low at birth and increases in parallel with myelination and maturation. The brain specific gravity of litters from mice exposed to trichloroethylene (TCE) before and after mating was significantly lower than in litters from unexposed parents at birth as well as at the age of 10 and 20-22 days. This might indicate a delayed maturation. No significant difference between exposed and unexposed litters was observed at the age of one month.

Age Factors↗

PubMed1982

Effect of intravenous fluid and drug solution coadministration on final-infusate osmolality, specific gravity, and pH.

The effects of i.v. fluid rates and i.v. drug delivery rates on osmolality, specific gravity, and pH of the resulting infusate were examined. Selected drug solutions of various osmolalities and 5% dextrose and 0.2% sodium chloride injection or Ringer's injection, lactated, were administered simultaneously using a drug delivery system capable of controlling the flow rates independently. The i.v. fluid and drug infusion rates were varied from 4 to 46 and from 2 to 31 ml/hr, respectively. Osmolality, pH, and specific gravity of the drug solutions and final infusate were measured. Using alligation, the osmolality, pH, and specific gravity of the final infusate were calculated; correlations between observed and calculated values were computed. Guidelines for achieving an osmolality of the final infusate less than 500 mOsm/kg water were calculated. The observed and calculated osmolality and specific gravity of the final infusate were significantly correlated (r = 0.91, p less than 0.001, and r = 0.99, p less than 0.01, respectively). The pH of the final infusate was dependent on the pH of the original drug solution and was not affected by i.v. fluid and drug delivery flow rates. Osmolality may be an important factor to consider when establishing ideal drug solution infusion rates or concentrations. The infusate osmolality can be controlled by adjusting the concentration of the drug solution, drug infusion rate, or the i.v. fluid flow rate.

Hydrogen-Ion Concentration↗

PubMed1977

[Determination of the specific gravity of the urine using a refractometer].

A method is proposed for urine specific gravity determination by urine refractometric index reading. Only two-three drops are required. Abbe refractometer is used. The urine specific gravity is determined by the formula: (formula: see text), where y = urine specific gravity, x = the refraction read. The method could not be used in cases with glucosuria and ketoniria as well as in case of a considerable proteinemia. The author's results correlate with the results of some foreign authors.

Humans↗

PubMed2002

Values of urine specific gravity for thoroughbred horses treated with furosemide prior to racing compared with untreated horses.

The distribution of specific gravity values for 2,599 urine samples collected from racing Thoroughbred horses that were known to have received furosemide prior to racing was compared with that for 1,669 urine samples from racing Thoroughbred horses that reportedly had not received furosemide. Values of specific gravity for furosemide-treated horses were significantly lower (P < 0.001) than those for horses that had not received furosemide, and the proportion of horses with urine specific gravity either <1.010 or <1.012 was significantly greater (P < 0.001) among the furosemide-treated horses. These data indicate that evaluation of urine specific gravity would be a useful component of drug testing programs for regulation of furosemide use.

Animals↗

PubMed1987

Specific gravity measurements of lamb carcass joints.

10 Ossimi lamb carcasses were used to determine the specific gravity values of different joint cuts. The correlation coefficients were established between the specific gravities of these joints and the percentages of fat and muscle in the rib saddle joint. It was found that the gravity of different carcass sections was significantly related to the muscle and fat percentages in the rib saddle joint. The results indicate that the specific gravity values of carcass sections can be utilized for a practical estimate and assessment of carcass components.

Adipose Tissue↗

PubMed1986

Changes in specific gravity as a sign of disturbed brain maturation in protein-deprived rats.

The specific gravity of the cerebral cortex of normal and protein-deprived rats aged 15, 21 and 25 days was determined. The increase in specific gravity seen in control rats in the course of their development was reduced in protein-deprived rats in the course of the period between 15 and 21 days of age. The results are in agreement with previous reports on delayed maturation of the brain in protein-deprived rats and indicate that determination of brain specific gravity may serve as a suitable screening method in situations when a disturbed brain maturation is suspected.

Animals↗

PubMed2005

Effect of creatinine and specific gravity normalization techniques on xenobiotic biomarkers in smokers' spot and 24-h urines.

Renal excretion mechanisms are xenobiotic-specific; therefore, accurate exposure assessment requires an understanding of relationships of xenobiotic biomarker concentration and excretion rate to urine flow, specific gravity and creatinine concentration. Twenty-four-hour urine collection for xenobiotic exposure assessment is considered the "gold standard" procedure. Random spot-urine collection is convenient and minimizes subject compliance concerns but requires that normalization techniques be employed to account for diuresis and diurnal variation in xenobiotic biomarker excretion. This paper examines and makes recommendations concerning normalization techniques and conditions under which spot-urine results most accurately reflect 24-h urine results. Specific gravity, creatinine, and xenobiotic biomarkers were determined in smokers' spot and 24-h urines. Normalization techniques were applied, variance-component analyses were performed to estimate variability, spot urines were pooled mathematically to simulate 24-h urines and analyses of variance were performed to evaluate spot urines' ability to reflect 24-h urine concentrations. For each xenobiotic biomarker concentration, log-linear relationships were observed with urine flow, specific gravity, and creatinine. For most xenobiotic biomarker excretion rates, log-linear relationships were observed with urine flow; creatinine, however, was unaffected by urine flow. The conventional creatinine ratio-normalization technique demonstrated greater variability (within-day, between-day and between-subject) than other normalization techniques. Comparisons of simulated 24-h urines to spot urines suggest that spot-urine collection be performed only between 2 p.m. and 2 a.m. and that the modified specific-gravity-adjusted-creatinine ratio-normalization technique and the creatinine-regression normalization technique yield the best agreement between spot- and simulated 24-h urine results.

Biomarkers↗

PubMed1987

Correlation of specific gravity and osmolality of urine in neonates and adults.

There is good correlation between the specific gravity and osmolality of urine obtained from neonates and adults, if specimens contain neither protein nor glucose. The regression equations between specific gravity and osmolality, however, differ considerably between the two age groups, maturation to the adult regression occurring within the first 5 years of life. Specifically derived regression equations should therefore be used when predicting urine osmolality from measurement of specific gravity in neonates.

Adolescent↗

PubMed2001

Estimation of the probability for exceeding thresholds of urine specific gravity and plasma concentration of furosemide at various intervals after intravenous administration of furosemide in horses.

OBJECTIVE: To estimate the probability of concurrently exceeding thresholds for plasma concentration of furosemide and urine specific gravity after IV administration of furosemide in horses. ANIMALS: 12 mature healthy Thoroughbred (n = 6) or Quarter Horse (6) mares. PROCEDURE: Venous blood was collected from each horse prior to and 0.25, 0.5, 0.75, 1, 2, 3, 4, 4.5, 5, and 6 hours after IV administration of 250 mg (first experiment) or 500 mg (second experiment) of furosemide. Urine was collected hourly between 1 and 6 hours after administration of furosemide at both doses. Concentrations of furosemide were determined by use of an ELISA. Concentration of furosemide and urine specific gravity was modeled as a function of time, accounting for inter- and intrahorse variabilities. On the basis of pharmacokinetic and specific gravity data, the probability of exceeding a concentration of 100 ng of furosemide/ml as a function of time was determined, using a semiparametric smooth functional averaging method. A bootstrap approach was used to assess the inherent variation in this estimated probability. RESULTS: The estimated probability of exceeding the threshold of 100 ng of furosemide/ml and urine specific gravity < 1.012 was approximately 0% between 4.0 and 5.5 hours after IV administration of 250 mg of furosemide/horse, and ranged from 0 to 1% between 4 and 5.5 hours after IV administration of 500 mg of furosemide/horse. The probability of a horse being falsely identified as in violation of regulatory concentrations was inversely associated with time. CONCLUSIONS AND CLINICAL RELEVANCE: Coupling plasma furosemide concentration with urine specific gravity testing will greatly reduce the chance that some horses are misclassified as being in violation of regulatory concentrations.

Animals↗

PubMed1989

Influence of specific gravity and food on movement of granules in the gastrointestinal tract of rats.

The suitability of rats as an animal model for estimating the bioavailability of controlled-release granules in humans was investigated. Non-disintegrating granules (diameter of 0.8 mm; specific gravity of 0.9-1.85) were used as a model preparation. Twenty granules were administered to fed rats, fasted rats and rats given soft food, and the number of granules remaining in the gastrointestinal tract was counted at suitable intervals. Granules with a specific gravity of 1.25 administered to fasted rats were rapidly emptied from the stomach with a 50% gastric emptying time of 1 h as compared with granules with a specific gravity of less than 1.0 or with a high specific gravity such as 1.85. The presence of food in the stomach reduced the emptying rate of granules. The mean transit time of granules through the small intestinal tract was not influenced by the specific gravity or the presence of food. The mean transit time was about 3 h. It was found that the transit profile of granules through the gastrointestinal tract in rats was similar to that of granules in humans. Accordingly, it is possible to use rats at the preformulation stage for estimating the bioavailability of controlled-release granules in humans.

Animals↗

PubMed1983

Study of urinary specific gravity by reagent strip method.

A newly developed reagent strip method for determination of urinary specific gravity is described. This reagent strip (Chemical S.G., Ames Co.) contains polyelectrolyte which is sensitive to the cation in solution. The urinary specific gravity is mainly decided by cation (Na+ and K+) concentrations in urine. As a result, the reagent strip gave measurements that corresponded to those measured by refractometry and gravimetry of NaC1 solution. Urea and glucose gave increased values by the refractometer, whereas the reagent strip did not cause changes. The values of urinary specific gravity obtained from reagent strip showed not only good correlations (r = 0.79-0.93) with the refractometry and gravimetry but also urinary osmolarity. This reagent strip method proved to be a most convenient tool for routine urinalysis because of the good reproducibility and accuracy considering its easy handling.

Contrast Media↗

PubMed1973

Variation in plasma calcium with induced changes in plasma specific gravity, total protein, and albumin.

The relationship of plasma calcium levels to changes in plasma specific gravity, total protein, and albumin induced by venous stasis was investigated. Factors were derived for adjusting calcium results to offset the effects of variation in protein concentration and thus to make them of increased discriminatory value to the clinician. The validity of an existing specific gravity correction has been substantiated, but a more exact adjustment of 0.23 mg/100 ml of calcium for every 0.001 change in specific gravity is proposed. We recommend for automated laboratories that the factor based on albumin be used: 0.09 mg/100 ml of calcium should be subtracted from the total calcium value for every increase of 0.1 g in albumin above 4.6 g/100 ml, and a corresponding addition should be made for values of albumin below 4.6 g/100 ml.Using a calcium specific electrode, it has been shown that the ionized calcium concentration does not alter with prolonged venous stasis.

Adult↗

PubMed1992

The correlation between osmolality and specific gravity of parenteral nutrition solution.

The correlation between osmolality and specific gravity of parenteral nutrition solutions containing various concentrations of amino acid and glucose were studied. There is good correlation between osmolality and specific gravity up to 1,000 mOsmol/kg H2O and 1.050, respectively. There are strong correlations between osmolality and amino acid concentration at each concentration of glucose. An equation which can be applied for quick calculation of osmolality of the solution from amino acid and glucose concentrations is: Osmolality (mOsmol/kg H2O) = 74.36 G + 163.91 A - 36.56. The results of this study can be adopted by all physicians for quick assessment of the osmolality of the PNS before administration to patients.

Osmolar Concentration↗

PubMed2003

Comparison of 3 Methods to Assess Urine Specific Gravity in Collegiate Wrestlers.

OBJECTIVE: To investigate the reliability and validity of refractometry, hydrometry, and reagent strips in assessing urine specific gravity in collegiate wrestlers. DESIGN AND SETTING: We assessed the reliability of refractometry, hydrometry, and reagent strips between 2 trials and among 4 testers. The validity of hydrometry and reagent strips was assessed by comparison with refractometry, the criterion measure for urine specific gravity. SUBJECTS: Twenty-one National Collegiate Athletic Association Division III collegiate wrestlers provided fresh urine samples. MEASUREMENTS: Four testers measured the specific gravity of each urine sample 6 times: twice by refractometry, twice by hydrometry, and twice by reagent strips. RESULTS: Refractometer measurements were consistent between trials (R =.998) and among testers; hydrometer measurements were consistent between trials (R =.987) but not among testers; and reagent-strip measurements were not consistent between trials or among testers. Hydrometer (1.018 +/- 0.006) and reagent-strip (1.017 +/- 0.007) measurements were significantly higher than refractometer (1.015 +/- 0.006) measurements. Intraclass correlation coefficients were moderate between refractometry and hydrometry (R =.869) and low between refractometry and reagent strips (R =.573). The hydrometer produced 28% false positives and 2% false negatives, and reagent strips produced 15% false positives and 9% false negatives. CONCLUSIONS: Only the refractometer should be used to determine urine specific gravity in collegiate wrestlers during the weight-certification process.

Journal Article↗

PubMed2001

Urine specific gravity and water hardness in relation to urolithiasis in persons with spinal cord injury.

STUDY DESIGN: A matched case-control study. OBJECTIVES: To clarify the influence of urine specific gravity and drinking water quality on the formation of urinary stones in persons with spinal cord injury (SCI). SETTING: A rehabilitation center within a university hospital. METHODS: Between 1992 and 1998, 63 stone cases (31 kidney, 27 bladder, and five both) and 289 age-duration-matched controls were recruited from a cohort of SCI patients enrolled in an on-going longitudinal study. Data on urine specific gravity and other characteristics of study participants were retrieved from the database and medical charts. Community water supply information was provided by the Alabama Department of Environmental Management. Multivariable conditional logistic regression analysis was performed to evaluate the association with stone formation. RESULTS: SCI individuals who had urinary stones were more likely than control subjects to use indwelling catheters and have decreased renal function. The occurrence of stones was not significantly related to gender, race, severity of injury, urinary tract infection, nor urine pH. After controlling for the potential confounding from other factors, a continuously increasing stone occurrence with increasing specific gravity was observed (P=0.05); this association was stronger for kidney (odds Ratio [OR]=1.8 per 0.010 g/cm(3)) versus bladder stones (OR=1.2) and for recurrent (OR=2.0) versus first stones (OR=1.5). Increased water hardness was not significantly associated with a decreased stone occurrence. CONCLUSIONS: Study results suggest that maintaining urine specific gravity below a certain level might reduce the occurrence of urinary stones. This could be easily achieved by using a dipstick for self-feedback along with appropriate fluid intake. For persons with SCI who are at an increased risk of a devastating stone disease, this prophylactic approach could be very cost-effective; however, this requires further confirmation.

Adult↗

PubMed1985

[Evaluation of a method for determining the specific gravity of urine with a reagent strip].

The performance of a new reagent strip method for determining the urine specific gravity was evaluated. 342 clinical specimens were assayed in duplicate by the new method and by the "falling drop" technique. The reproducibility (two lots of strips, four operators) was very good (96.2 per cent agreement between replicates within a range of 0,0100 specific gravity units). The correlation with the comparative method was satisfactory [81,2 per cent concordance within a range of 0,0100 specific gravity units]. No interference was found from ketones, blood or urobilinogen. The influence of proteins and glucose is discussed. The practical advantages of the new method are described.

Acute Kidney Injury↗

PubMed1994

Specific gravities of desflurane, enflurane, halothane, isoflurane, and sevoflurane.

We determined the specific gravities of presently available volatile anesthetics in order to supply a consistent quantitative basis for calibration standards. Using four 50-mL volumetric flasks, we obtained the following values at 20 degrees C: desflurane 1.4651 +/- 0.0004 g/mL (mean +/- SD); enflurane 1.5230 +/- 0.0003 g/mL; halothane 1.8680 +/- 0.0007 g/mL; isoflurane 1.5019 +/- 0.0006 g/mL; and sevoflurane 1.5203 +/- 0.0008 g/mL. Measurements made at 0 degree C, 10 degrees C, 20 degrees C, and 25 degrees C (not for desflurane at 25 degrees C) revealed a decrease in specific gravity of 0.00250 +/- 0.00014 g/mL for each degree of increase in temperature. These data bear on the issue of cost for anesthetics that are stored as liquids, but used as gases.

Anesthesia, Inhalation↗

PubMedDate not supplied

The relation of egg specific gravity to the incidence of spontaneous cardiomyopathy in tom turkeys.

The specific gravity and weight of eggs were determined for two groups of 600 eggs each, originating from Nicholas and British United Turkey of America (BUTA) turkey breeder flocks. A total of 137 Nicholas and 190 BUTA toms hatched from these eggs were used for the experiment. At days 21, 33, 40, 47, 56, and 61, toms that showed retarded growth were euthanatized, along with a corresponding number of normal birds. Both groups were measured for body weight, heart weight, separate weights of left and right ventricles, and combined atrial weight. At market age, the remaining toms were weighed, and the hearts were checked at processing for lesions characteristic of spontaneous turkey cardiomyopathy (STC). STC was found in 10.2% of Nicholas and 8.4% of BUTA toms. No correlation could be found between specific gravity of eggs and incidence of STC. Body weights of affected toms were reduced during the growing period. At processing, 2.8% of toms had lesions of STC, and mean body weight was 1298 g lower than average. The ratios of combined atrial weight:body weight, right ventricular weight:body weight, left ventricular weight:body weight, and total heart:body weight were significantly higher at all times in affected toms than in controls, and the differences were the greatest at 3 weeks of age.

Animals↗