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Results for “Specific Gravity”

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At least 19 recordsLinked to original sources

PubMed1979

The effect of seasonal changes and socio-economic status on urinary pH and specific gravity.

Specific gravity and pH of urine in the dry and the wet season in three socio-economic Nigerian groups have been studied. Samples were collected at 7 a.m., 11 a.m. and 3 p.m. High-income subjects had a significantly lower urinary pH than low-income. During the wet season pH values were lower than in the dry, but not significantly so. During the day S.G. values did not differ, neither did they in different seasons. But there were significant differences between high and low income groups. S.G. and pH samples of high and low income groups were similar in children and in their parents. In medical students S.G. and pH in 24-hour urines were similar to the morning value of high and middle income groups and were not affected by season, but the volume was. The relevance of these findings is discussed relative to the rarity of urinary calculi in Nigerians.

Adult↗

PubMed1978

Analysis of cerebrospinal fluid specific gravity.

The specific gravity of 71 CSF samples from clinically normal dogs ranged from 1.004 to 1.006, with a mean of 1.005. A 3-year retrospective study of CSF samples obtained from 124 animals suspected of having neurologic disease revealed only 30 samples (24.2%) having a specific gravity greater than 1.006. Diagnostic or prognostic value from CSF specific gravity determination was not recognized.

Animals↗

PubMedDate not supplied

Determination of the specific gravity of human pineal.

Specific gravity values for the pineal gland in any species are lacking. These data are necessary for calculating and interrelating pineal weight and volume. This report deals with the specific gravity of human pineal gland. The specific gravity of fresh, unfixed human pineal has been determined to be 1.197 +/- 0.036 SEM at 20 degrees C (N = 11) using water as the measuring medium. By contrast, human brain has been reported in the literature to have a specific gravity of 1.036. Specific gravities of human pineals fixed in Bouin's fluid, Bouin's fluid followed by 80% ethanol, 80% ethanol, and embalming fluid were found to be 1.113 +/- 0.025 (N = 5), 0.941 +/- 0.009 (N = 5), 0.990 +/- 0.022 (N = 3), and 1.149 +/- 0.021 (N = 7), respectively. These are corrected values accounting for the specific gravities of the respective measuring fluids. It is shown that the specific gravity of human pineal as derived in this study is directly applicable to calculations of pineal volumes and weights not only in humans, but in other species as well.

Aged↗

PubMed1991

Differentiation of naphthalene and paradichlorobenzene mothballs based on their difference in specific gravity.

The present study was conducted to measure the specific gravities of paradichlorobenzene and naphthalene mothballs and compare them with the specific gravity of a saturated aqueous solution of sodium chloride (1.197). The specific gravities of 450 paradichlorobenzene mothballs from 5 manufactures and 150 naphthalene mothballs from 2 manufactures were measured with a specific gravity meter. The mean specific gravities of paradichlorobenzene mothballs were between 1.429 and 1.437 (p = 0.99). On the other hand, the mean specific gravities of naphthalene mothballs were between 1.094 and 1.100 (p = 0.99). Based on the fact that paradichlorobenzene mothballs sink in a saturated solution of salt whereas naphthalene mothballs float on it, these 2 kinds of mothballs ought to be rapidly and accurately distinguished in clinical settings.

Chlorobenzenes↗

PubMed1979

A comparison of urinary specific gravity and osmolality in sheep.

Urinary specific gravity and osmolality were determined on urine samples collected from three categories of sheep -- animals that were normal, in diuresis or had nephron numbers reduced surgically. Values for specific gravity and osmolality were compared and regression coefficients calculated for each category of sheep. In this study, specific gravity was found to be a relatively reliable indicator of osmolality, the correlation being highest in the urine from the sheep with reduced nephron numbers.

Animals↗

PubMed1991

Effect of source and amount of fiber on kinetics of digestion and specific gravity of forage particles in the rumen.

This experiment investigated the relationship between kinetics of digestion and change in specific gravity during in situ incubation. Nine cows were fed three sources of fiber (corn silage, alfalfa silage, or alfalfa hay) in diets formulated to contain 25, 30, or 35% NDF in three simultaneous 3 x 3 Latin squares. Method of alfalfa preservation did not influence rate of digestion or rate of increase in specific gravity of forage particles measured by a flotation technique. Prior to incubation, specific gravity of forage particles was in increasing order: alfalfa hay, alfalfa silage, and then corn silage. Essentially, all particles with a specific gravity less than 1.0 shifted to a higher specific gravity fraction by hydration within the first 4 h of incubation. From 4 to 56 h of incubation, percentage of residual DM that settled in solution having specific gravity of 1.3 increased linearly from 21 to 27% for corn silage but exponentially from 3 to 20% for alfalfa forages. Fractional rates of DM and NDF digestion and increase in percentage of residual DM having a specific gravity greater than 1.3 increased with the amount of fiber in the alfalfa diets and were correlated positively, suggesting that rate of increase in specific gravity, which affects rate of passage from the rumen, is influenced by rate of digestion of forage particles.

Animal Feed↗

PubMed1991

Measurement of brain tissue specific gravity using pycnometry.

In this paper we introduce and characterize pycnometry, a method used to measure fluid density, for determining a tissue's specific gravity. It uses a 2-ml glass pycnometer filled with distilled water to determine a tissue sample's displacement volume. The tissue's density is determined when it's weight is divided by this volume and specific gravity is computed by dividing the tissue density by the density of water. Pycnometry was validated using pre-calibrated glass, specific gravity standards over the range 1.03-1.26, and compared to the density gradient method using rat brain tissue. We observed that the specific gravity values obtained using pycnometry were highly correlated with the specific gravity standards (slope = 1.0107, r = 0.996) and with the density gradient column when tissue volumes larger than 0.120 ml were used with the pycnometer (slope = 1.0707, r = 0.9826). Good correlation was also observed between percent water content values computed using the Nelson equation with pycnometry or density gradient specific gravity values versus the measured percent water content values obtained with the wet weight/dry weight method. Pycnometry is an accurate, reproducible technique to measure tissue specific gravity and brain edema and is best suited for use in a laboratory that engages sporadically in brain edema measurement.

Animals↗

PubMed1992

Specific gravity of bovine colostrum immunoglobulins as affected by temperature and colostrum components.

The effects of temperature and colostrum components on specific gravity in bovine colostrum were investigated. Thirty-nine first milking colostrum samples were collected from Holstein cows. The samples were assayed for alpha-tocopherol, fat, protein, total solids, and IgG. The concentrations of total solids, total protein, total IgG, and fat in colostrum were 26.6, 12.5, 3.7, and 9.4 g/100 g, respectively. A range of 1.8 to 24.7 micrograms/ml for alpha-tocopherol was measured in the colostrum samples. Specific gravity of the colostrum was measured using a hydrometer in increments of 5 degrees C from 0 to 40 degrees C. Specific gravity explained 76% of the variation in colostral total IgG at a colostrum temperature of 20 degrees C. The regression model was improved only slightly with the addition of protein, fat, and total solids. The model for samples at 20 degrees C was IgG (milligrams per milliliter) = 958 x (specific gravity) - 969. Measurement of specific gravity at variable temperatures necessitated inclusion of temperature in the model for estimation of IgG. Inclusion of the other components of colostrum into the model slightly improved the fit. The regression model for samples at variable temperatures was as follows: IgG (milligrams per milliliter) = 853 x (specific gravity) + .4 x temperature (Celsius degrees) - 866.

Animals↗

PubMed1989

Modelling the relationships of egg weight, specific gravity, shell calcium and shell thickness.

1. The relationships between egg weight, egg specific gravity, shell weight, shell calcium and shell thickness of 800 eggs from 8 treatments were expressed using mathematical models. 2. The equations describing the relationships were on the basis of any two independent variables predicting the remainder. 3. Of 10 possible models, 4 had high co-efficients of determination (R2 greater than 0.80) for each predicted dependent variable. 4. The two independent variables in each of these 4 models were, in turn, egg weight and specific gravity, egg weight and shell weight, egg weight and shell thickness, and specific gravity and shell weight. 5. The best model was that having egg weight and specific gravity as independent variables, with R2 values of 0.94, 0.88, and 0.85 for predicted shell weight, shell calcium, and shell thickness, respectively. Moreover, egg characteristics can be measured non-destructively by this model, whereas the other three require destruction of the egg.

Age Factors↗

PubMed1979

Falsely high refractometric readings for the specific gravity of pleural fluid.

For 128 pleural fluids, the relationship between the protein content and the reading for the specific gravity obtained from a refractometer calibrated for urinary specific gravity was analyzed. The refractometer gave falsely high levels for the specific gravity of the pleural fluid. A reading for 1.019 (rather than 1.016) corresponded to a concentration of protein of 3.0 gm/100 ml, and each deviation of 0.005 (rather than 0.003) coresponded to a concentration of 1 gm/100 ml; however, determinations of the concentration of protein in the pleural fluid directly from the refractometer's scale for protein (calibrated for serum) was rapid and accurate. Calculation of the protein content of the pleural fluid from the reading for specific gravity on the refractometer is erroneous and sometimes misleading.

False Positive Reactions↗

PubMed1991

The urine specific gravity dipstick: a useful tool to increase fluid intake in stone forming patients.

High fluid intake is the only preventive dietary measure that can be recommended to all patients with stones. However, the efficacy of dietary advice given to patients is unknown. We compared the impact of dietary advice to increase hydration (group 1, 57 patients) and of no dietary advice (group 2, 83 patients) on 24-hour urine volume. No significant difference was noted between groups 1 (1,624 ml.) and 2 (1,732 ml.). We then determined if urine specific gravity dipsticks could help patients increase the 24-hour urine volume. A correlation between 24-hour urine volume and mean urine specific gravity was performed on 263 randomly chosen patients. There was an inverse relationship between urine specific gravity and 24-hour urine volume with a correlation coefficient of 0.522 (y = 1.0207 - 0.00374x). Most patients (81.6%) with 24-hour urine volumes of less than 2.1 had a urine specific gravity of more than 1.010. The use of specific gravity dipsticks was evaluated as a tool to help 24 patients increase the 24-hour urine volume. The 24-hour urine volume increased significantly (p less than 0.05, paired Student's t test) in patients after feedback from specific gravity dipsticks when they were instructed to keep the urine specific gravity at or less than 1.010 (average 24-hour urine volume increased 192%). We conclude that dietary advice may be insufficient to modify fluid intake habits in stone patients. However, modifications of fluid intake habits may be improved by feedback from specific gravity dipsticks.

Adolescent↗

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↗

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↗

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↗

PubMed1979

Correlation of absorption coefficients with intracranial fluid protein concentrations and specific gravities.

Samples of ventricular cerebrospinal fluid, tumor cyst fluid, and subdural fluid were obtained from 30 patients at operation. The protein concentration and the specific gravity of each sample were measured and the corresponding mean absorption numbers were calculated from the numerical printout of the preoperative computerized tomogram. For fluids with a specific gravity greater than 1.005, a linear relationship was demonstrated between protein concentration and specific gravity. For protein concentrations greater than 300 mg/dl, there was a linear relationship between protein concentration and the mean absorption number. As the precision of present instrumentation improves, it is expected that a noninvasive technique for estimating intracranial protein concentration will have a number of clinical application.

Absorption↗

PubMed1975

Determination of the glomerular filtration rate by the minute diuresis at a specific gravity of 1001.

A new method is described for determination of the glomerular filtration rate, based on the fact that at an urinary specific gravity of 1001 the final urine is concentrated 6.67 times, as compared with the primary glomerular filtrate. The glomerular filtration rate is evaluated by multiplication of the minute diuresis at a specific gravity of 1001 by the factor 6.67. In this manner the chemical analysis of urine and blood is avoided. Urine with a specific gravity of 1001 is obtained by water loading much the same as in the dilution test of Volhard. For checking the accuracy of the method, comparative studies were conducted with creatinine clearance in 36 patients and with 51Cr-EDTA clearance in 33 patients. The difference in the values of the glomerular filtration rate, evaluated by the above-mentioned two methods and the new method was statistically not significant (p greater than 0.05). The method is recommended for the early detection of disturbances in the glomerular function prior to the occurrence of azotemia.

Diuresis↗

PubMedDate not supplied

[Correlation between osmolarity and specific gravity of urine. Changes caused by the presence of abnormal solutes].

There is a high correlation index (0.97) in the measurement of urine osmolality and specific gravity in healthy children and adults and in children with renal disease without heavy proteinuria or glucosuria. This is a useful tool, because osmometers are not used in many laboratories, but specific gravity is of general use, so that urine concentration in mOsm/kg. can be derived from the specific gravity. The same parameters in urines with heavy proteinuria or glucosuria were also measured and the correlation index and the modifications per gram of abnormal solute that should be applied in order to obtain the correct urine concentration figures, were established.

Adult↗

PubMed1992

Kinetics of hydration and effect of liquid uptake on specific gravity of small hay and silage particles.

Kinetics of hydration of ground hay and silage particles (2-mm screen), determined by a pycnometric technique, was best described by a two- and one-pool exponential model, respectively. Fractional rates of hydration of the large pool, detected in hay particles only, and of the small pool present in both hay and silage particles averaged .135 and .021 min-1, respectively. When hydration was complete, liquid associated with particles averaged 1.16, 1.90, and .83 g/g of insoluble DM for bromegrass hay, alfalfa hay, and alfalfa silage, respectively. Functional specific gravity, which accounts for the effect of associated gas volume, averaged 1.54, 1.46, and 1.54, but unit specific gravity, calculated to include the effect of gases and liquid of hydration, averaged 1.22, 1.14, and 1.26 for bromegrass hay, alfalfa hay, and alfalfa silage, respectively. Preservation of forage as silage not only lowered gas volume, but also reduced water-holding capacity, both of which contribute to greater unit specific gravity and faster rate of escape from the rumen. In addition, estimates of unit specific gravity of approximately 1.2 indicate that even in the absence of associated gas, hydrated forage particles would tend to escape the rumen at a slower rate than that achieved by more dense particles.

Animal Feed↗