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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↗

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↗

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↗

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↗

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↗

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↗

PubMedDate not supplied

[The evaluation of the specific gravity of Giardia duodenalis and Entamoeba coli cysts].

Cysts of Giardia duodenalis and Entamoeba coli were observed as for floatability in sucrose solutions of different specific gravity, contained in counting-chambers of 0.17 mm height. The cysts that floated and those that sedimented were counted and then calculated the respective percentage. Floatability differences of the cysts of each species were not considerable. Solutions of specific gravity 1,200 kg/m3 made 88.49% of G. duodenalis cysts and 95.71% of E. coli cysts float. The greater values of floatability were associated to specific gravity 1,250 kg/m3 and were 89.15% and 98.59% for cysts of G. duodenalis and E. coli, respectively.

Animals↗

PubMed1975

The effect of light and specific gravity on embryo weight and embryonic mortality.

Eggs from Single Comb White Leghorn chickens were divided into two approximately equal groups with the range of specific gravities being present in each group. One group was incubated in a darkened Humidaire Hatchett while the other was incubated in an identical machine equipped with two 20 Watt fluorescent tubes which produced 8.3 X 10(3) ergs/cm.2-sec. at the surface of the eggs. The recommended temperature and humidity settings were used in both machines. After 7 days of incubation embryos from the lighted incubator were significantly (P less than .01) larger than those incubated in the dark. There were significantly more live embryos from low and high specific gravity eggs in the light than in the dark. There was no difference in embryonic mortality between groups for the eggs with intermediate specific gravities. Embryos from White Leghorn eggs incubated in the presence of light were significantly (P less than .01) larger on each day of incubation from day 2 through hatch. Eggs incubated in the lighted incubator hatched at 18 and 19 days and produced larger chicks than those hatched at 20 and 21 days in the dark.

Animals↗

PubMed1976

Correlative assay of computerized cranial tomography CCT, water content and specific gravity in normal and pathological postmortem brain.

An assay of water content and specific gravity in normal and pathological autopsy brain has been correlated with CCT attenuation values obtained just prior to brain cutting. Formalin fixation does not alter normal values so that fixed brain appears to be suitable for this type of study. Low attenuation values in CCT correlate better with changes in specific gravity, rather than water in infarcts, but they have a close relationship to water content in edema. The high water content in infarcts of the white matter reveals a striking disparity in fluid control between cortex and white matter, which has not been emphasized in experimental studies. Water movement within and around blood clots has been discussed.

Body Water↗

PubMed1992

Experimental studies of the combined use of vitreous substitutes of high and low specific gravity.

The combined use of high and low specific gravity liquid vitreous substitutes has been studied in the rabbit. Eyes having undergone 1) vitreous replacement with silicone liquid combined with a perfluoropolyether liquid of high viscosity; 2) replacement with the perfluoropolyether or silicone alone; or 3) vitrectomy only (control) were compared under conditions of a cell-injection model of traction retinal detachment. Some of the control eyes (3 out of 9) and silicone-filled eyes (2 out of 10) developed total retinal detachments involving all quadrants; in the silicone-filled eyes the detachments extended behind the silicone globule. Conversely, in the eyes undergoing replacement with the two liquids or with the perfluoropolyether liquid alone, retinal detachments never extended to the inferior quadrants underlying the perfluoropolyether globule. In other experiments, the tendency toward emulsification of a low-viscosity perfluorocarbon liquid was reduced when it was used in combination with silicone liquid, in comparison to when this liquid was used alone.

Animals↗

PubMed1978

Shell gland oxygen consumption in hens producing eggs of low or high specific gravity.

Oxygen consumption of shell gland lumenal tissue was found to be higher in hens producing eggs of high specific gravity (greater than or equal to 1.080) when compared to tissue from hens producing eggs of low specific gravity (less than or equal to 1.075). Shell gland lumenal tissue oxygen consumption was also greater when an egg was in the shell gland as compared to hens with an egg in the magnum (9.8 and 8.0 microliter O2/hr/mg tissue respectively).

Animals↗

PubMed1977

Variation in the weight, specific gravity and composition of the antlers of red deer (Cervus elaphus L.).

1. Antlers were removed in September from 2-4 year old red deer (Cervus elaphus L.). Both well-fed penned stags and less well-nourished grazing stags were studied. 2. For deer of the same age, both log antler weight and log antler specific gravity were related to body-weight in September and to body-weight gain between March and September. The antlers of 3- and 4-year-old stags were heavier and tended to be denser relative to body-weight and body-weight gain than those of 2-year-old stags. 3. For grazing stags of a given age, antler weight and specific gravity, and body-weight and body-weight gain, were progressively less in the three successive years of the study. This appeared to reflect increasing stocking rate over this period. 4. The composition of the antlers did not vary significantly between penned and grazing stags or with age. However the concentrations of ash, phosphorus and magnesium in dry matter showed significant positive correlations with specific gravity, that of zinc a significant negative correlation, while calcium, copper and manganese showed no significant correlation. 5. The antlers evidently provide a useful index of the changes in body-weight of the stags.

Animal Nutritional Physiological Phenomena↗