Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SPECIFIC GRAVITY”

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.

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

At least 811 records · Page 45Linked to original sources
PubMed1991

Effects of feeding flax and two types of sunflower seeds on fatty acid compositions of yolk lipid classes.

Single Comb White Leghorn laying hens were fed diets high in oleic, linolenic, or linoleic acid prepared by incorporation of high oleic acid sunflower seed (HOAS), full-fat flax seed (FLAX), or regular high linoleic acid sunflower seed (HLAS), respectively, to investigate the effects of dietary fats on the fatty acid compositions of major lipid classes of chicken eggs. Egg production, Haugh units, specific gravity, and yolk total lipid content were measured. After 3 wk of feeding, the fatty acid compositions of yolk total lipids, triglycerides, phosphatidylcholine (PC), and phosphatidylethanolamine (PE) were measured by gas chromatography. Dietary treatments had no effect on egg production, Haugh units, specific gravity, or yolk total lipid content. Feeding HOAS increased yolk oleic acid by 17%, and the change was only in triglycerides. The increases of yolk linoleic and arachidonic acids upon HLAS feeding were distributed evenly among triglycerides and PC, with moderate effect in the PE fraction. The enrichment of linolenic acid in eggs from the FLAX regime was mainly in triglycerides. The longer chain n-3 fatty acids, such as eicosapentaenoic, dososapentaenoic, and docosahexaenoic acids, were deposited exclusively in phospholipids, particularly in PE. The contents of the longer chain n-3 fatty acids in PE were three to seven times those in PC, indicating a preferential incorporation of these fatty acids into PE.

Animal Feed↗
PubMed2002

Cerebral physiological and biochemical changes during vasogenic brain oedema induced by intrathecal injection of bacterial lipopolysaccharides in piglets.

BACKGROUND: The objective of the study was to evaluate biochemical and physiological changes in an experimental model of vasogenic brain oedema utilising techniques also used in routine neurointensive care. METHOD: 32 piglets were randomised to control or experimental group. The latter received an intrathecal injection of lipopolysaccharide (LPS) from E. coli (LPS group). Intracranial pressure (ICP)and mean arterial pressure (MAP) were measured continuously. Intracerebral microdialysis was used for analysing interstitial levels of glucose, pyruvate, lactate, glutamate, glycerol and urea every 30 min. Repeated calculations of mean hemispheric CBF were performed utilising an extracranial scintillation detector and Intra-carotid injection of (133)Xe. Cerebral specific gravity was measured and the brains were fixed for histological examinations. FINDINGS: After LPS injection ICP increased reaching a plateau phase after 4-7 hours and CBF increased by 46%. Histological examination showed inflammation with pronounced extravasation of granulocytes. A significant decrease in brain specific gravity (p =0.022) was obtained. LPS caused a significant decrease in cerebral interstitial concentration of glucose (p = 0.0035), and significant increases in lactate concentration (p = 0.002) and lactate/pyruvate ratio (p = 0.0017). A small but significant increase in glutamate was obtained (p = 0.0219). Glycerol did not change significantly. INTERPRETATION: Intrathecal LPS caused an inflammatory reaction with extravasation of granulocytes, increased blood-brain barrier permeability and cerebral oedema. Biochemical analyses indicate increased glycolysis but no signs of cell membrane degradation.

Animals↗
PubMed1982

A 31P nuclear magnetic resonance in vivo study of cerebral ischaemia in the gerbil.

We have used the noninvasive method of 31phosphorus nuclear magnetic resonance (31P NMR) in vivo to follow changes in phosphorous metabolite concentrations and the intracellular pH in the right and left hemispheres and in the cerebellum of gerbil brains after the occlusion of the right carotid artery. Spatial resolution over the brain was possible using surface coils. Ligation, which is know to cause ischaemia in this species in the ipsilateral hemisphere, resulted in the diminution of phosphocreatine and adenine nucleotides and a decrease in tissue pH. Less acidification occurred in the contralateral hemisphere and in the cerebellum. The high-energy metabolite concentrations, phosphocreatine and adenosine triphosphate (ATP), declined in unison in the ischaemic region, in marked contrast to the sequence of events in skeletal muscle, in which phosphocreatine buffers against an immediate fall in ATP concentration. In a separate series of gerbils, 31P NMR spectra were followed for exactly 1 h after carotid ligation. The animals were then sacrificed and brain grey matter specific gravity was rapidly measured to assess the development of oedema. There was a clear correlation between abnormality of spectra and the presence of oedema. It cannot, however, be confidently asserted that a normal spectrum is never seen in oedematous gerbil brains. 31P NMR spectra specific gravity and histological changes shown by light microscopy have been correlated and show that useful signals are received from a depth of at least 4 mm or more from the 10-mm diameter coil.

Adenine Nucleotides↗
PubMed1989

Accumulation of calcium in the brain following head trauma.

Previous studies have reported accumulation of calcium (Ca) in brain tissue of injured or ischaemic experimental animals. In the present study, head trauma (HT) was induced in the left hemisphere of rats which were subsequently sacrificed 15 min, 1, 2, 4, 24 or 48 h later. Their brains were analysed for oedema formation by the determination of specific gravity (SG), using linear gradient columns, and water content, by dry to wet weight ratio. Total tissue Ca content was measured by atomic absorption spectroscopy. These values, in both the injured and contralateral hemispheres were compared with values obtained from sham-operated rats. Specific gravity of the contused hemisphere was lower than that of the contralateral hemisphere or sham and its water content was higher, at all time points studied. Calcium content was significantly higher in the contused grey matter at 1 h, and in the grey and white matter of both hemispheres at 24 and 48 h after HT. Statistical analysis revealed excellent correlation (cc = 0.65, p less than 0.001) between Ca levels and water content in the grey matter, whenever Ca concentrations were elevated (1, 24 and 48 h). These findings suggest that in the late phase of the post-HT period, Ca accumulation might play a role, along with other mediators, in the development of brain oedema after HT.

Animals↗
PubMed1986

Influence of dietary ingredients on calcium utilization in the laying hen.

Experiments were conducted to evaluate the benefit of calcium supplementation with or without other dietary ingredients on egg shell quality. A total of 250 Hyline hens, 44 weeks of age, were randomly divided among five treatments (Experiment 1). The dietary treatments were as follows: Treatment 1, controls (C) were fed a 3.5% calcium diet ad libitum; Treatment 2, hens were fed a .08% calcium diet (LC); Treatment 3, hens were intubated with limestone following 24-hr consumption of .08% calcium diet (LCI); Treatment 4, feed removed for 24 hr (NF); Treatment 5, feed removed for 24 hr and hens then intubated with limestone (NFI). All diets were restored to the control calcium level after 48 hr. Experiment 2 was identical to Experiment 1 except Dekalb XL hens, 50 weeks of age, were used. Eggs were collected daily for 5 days for egg specific gravity, egg weight, and shell weight determinations. Forty hens were sacrificed in Experiment 2 at 48 hr into the experiment to measure calcium distribution in the gastrointestinal (GI) tract and feces. Results indicated that hens fed the LCI treatment produced eggs with significantly higher specific gravity and heavier shells than hens given limestone with an empty GI tract. The calcium analysis of the GI tract revealed that much of the calcium supplement did not move beyond the gizzard in hens fed the NFI treatment. It was concluded that hens not only needed other nutrients for maximum utilization of dietary and skeletal calcium, but other nutrients or dry matter may also be needed to facilitate the passage of calcium from the gizzard.

Animal Feed↗
PubMed2000

Markers of hydration status.

This paper reviews the literature, describes and discusses methods by which whole body hydration status can be determined in humans. A method of determining whether or not an individual is hypohydrated is of particular significance in an exercise situation as even moderate levels of hypohydration have a negative impact on exercise performance. Inspection of the published literature indicates that a number of methods have been used to determine hydration status. Body mass changes, urinary indices (volume, colour, protein content, specific gravity and osmolality), blood borne indices (haemoglobin concentration, haematocrit, plasma osmolality and sodium concentration, plasma testosterone, adrenaline, noradrenaline, cortisol and atrial natiuretic peptide), bioelectrical impedance analysis, and pulse rate and systolic blood pressure response to postural change are discussed. The urinary measures of colour, specific gravity and osmolality are more sensitive at indicating moderate levels of hypohydration than are blood measurements of hematocrit and serum osmolality and sodium concentration. Currently no "gold standard" hydration status marker exists, particularly for the relatively moderate levels of hypohydration that frequently occur in an exercise situation. The choice of marker for any particular situation will be influenced by the sensitivity and accuracy with which hydration status needs to be established together with the technical and time requirements and expense involved.

Body Water↗
PubMed2001

Evaluation of spore extraction and purification methods for selective recovery of viable Bacillus anthracis spores.

AIMS: To investigate methods of improving anthrax spore detection with PLET. METHODS AND RESULTS: Comparisons were made of PLET and blood-supplemented PLET to recover and distinguish spores of a variety of Bacillus species. Heat and ethanol purification of spores, and spore extraction from soil with water and high specific gravity sucrose plus non-ionic detergent, were also carried out. CONCLUSION: PLET was more selective and suitable than blood-supplemented PLET for detection of anthrax spores in the environmental specimens. However, PLET is not an optimal spore recovery medium. Purification of spores with ethanol was as effective as heat purification. High specific gravity sucrose plus detergent extraction solutions may be more sensitive than extraction with water. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights shortcomings with the standard PLET isolation of anthrax spores and describes ways in which the procedure may be improved.

Bacillus anthracis↗
PubMedDate not supplied

Body electrolytes in bronchopulmonary dysplasia and the effects of diuretic therapy.

Body electrolytes and their regulatory hormones were studied in preterm infants who suffered from bronchopulmonary dysplasia under two groups: those who were not treated with diuretics (Group II), and those who were treated with diuretics (Group III). The values were compared with a group of matched healthy controls (Group I). Lower serum Na levels, a need of higher Na intake, and higher urinary Na concentrations and urinary specific gravity were found in Group II infants. FeNa was normal and the urinary flow rate was lower than the controls. These data suggest an inability of these infants to dilute urine. Group III infants who were treated with diuretics showed higher serum Na levels and lower urinary specific gravity than Group II infants. These values, as well as water and Na intake/output ratios, were all similar to the control values. Serum aldosterone level was highest in Group II but did not reach significance. Intracellular K concentration was not different between the groups indicating an optimum total body K balance. A significant negative correlation between serum Na and aldosterone levels was found in Group II infants, which was not noted in the controls. Significant correlations were also found between FeNa and plasma aldosterone level in the BPD groups, unlike the controls. The control group of infants showed significant positive correlation between Na balance and serum Na levels. Our results suggest that inability to dilute urine appropriately might be the reason for the BPD patients to retain body water. Water restriction and diuretic therapy therefore are reasonable therapeutic approaches in such cases.

Bronchopulmonary Dysplasia↗
PubMed2001

Evaluation of Aution Max AX-4280 automated urine test-strip analyser.

Aution Max AX-4280, an automated urine test-strip analyser, was evaluated in three centres. Method comparison, imprecision, carry-over, linearity, detection limit and drift studies were performed for glucose, protein, blood and leukocytes using Uriflet S 9UB strips. These strips enable measurement of pH, glucose, protein, blood, leukocytes, ketones, bilirubin, urobilinogen and nitrite. Specific gravity is determined by the refractive index method. Within-run and between-day imprecision, assessed using pooled urines and quality control materials, were good. No drift over 24 h or sample carry-over was observed. Method comparison with quantitative methods for glucose, protein and specific gravity yielded good correlations. Ascorbate negatively interfered with haemoglobin, glucose and nitrite measurements. Acetylsalicylic acid lowered pH, the effect being greatest when protein was absent. During the assessment period no malfunction or breakdown was reported. The Aution Max is easy to use and needs minimal maintenance.

Ascorbic Acid↗
PubMedDate not supplied

Evaluation of two new liquid-liquid oxygenators.

The authors devised two liquid oxygenator units in which blood is directly oxygenated with oxygenated perfluorocarbon (PFC), a substance harmless to the blood that has a high specific gravity. 1) The droplet-type oxygenator unit is composed of a blood oxygenating chamber and a PFC oxygenating chamber. Blood is oxygenated by the infusion of PFC droplets into the blood oxygenating chamber; PFC is then spontaneously separated from the blood because of a difference in specific gravity, and reoxygenated in the PFC oxygenating chamber. Experimental results obtained using mongrel dogs indicated this oxygenator to have a high efficacy of oxygenation (Qp/Qt = 0.63-0.78 with blood flow of 450-300 ml, O2 Transfer Rate = 64 ml/min with blood flow of 300 ml), and high carbon dioxide discharge (delta CO2/PaCO2 = 0.07-0.13, CO2 Transfer Rate = 11 ml/min with blood flow of 300 ml). Pathology examination showed microthrombi containing PFC in the lung and liver. 2) The disk type oxygenator unit is composed of a cylinder and 18 rotors connected to an axle. Oxygenated PFC enters into the lower part of the oxygenator and mixes with venous blood flowing above the PFC layer. The rotation of the disk in the oxygenator causes the blood and PFC to mix. Experimental results obtained using mongrel dogs showed excellent O2 exchange (Qp/Qt = 0.48-0.83, O2 Transfer Rate = 52 ml/min with blood flow of 300 ml) and CO2 removal capacity (delta CO2/PaCO2 = 0.05-0.10, CO2 Transfer Rate = 9 ml/min at blood flow rate of 300 ml/min) for 2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Mechanical properties of dewatered sewage sludge.

The mechanical properties of dewatered, anaerobically digested sewage sludge were determined from soil laboratory tests. The sludge material is largely composed of organic clay sized-particles, a sizable fraction of which is in an active state of biological digestion which can continue over many years under field conditions. Moderately digested sludge material was found to have a typical specific gravity of solids value of 1.55, and loss on ignition (LOI) value of 70% dry mass. Strongly digested sludge, produced by digesting the liquid sludge further at 35 degrees C in the laboratory, was found to have a lower LOI value of 55% dry mass, and a higher specific gravity of solids value of about 1.72. The maximum dry density of 0.56 tonne/m3 for the dried sludge material was produced using standard Proctor compaction at roughly 85% moisture content (54% solids content). Air-dried, compacted sludge material was tested in quick-undrained triaxial compression and vane shear. Undrained shear strength-moisture content plots are presented. Shear strength values measured in triaxial compression and vane shear were consistent. The effective angle of shearing resistance (phi') was determined from consolidated-undrained, triaxial compression tests on pasteurized, normally consolidated samples of the sludge material. The mechanical properties of the sludge material changed with the level of sludge digestion. The phi' value increased from 32 degrees for moderately digested sludge, to 37 degrees for strongly digested sludge. The effective cohesion of the sludge material remained zero throughout. The shrinkage, swelling and adhesion properties of the sludge material were also studied. Significant shrinkage occurred as the compacted material dried. The sludge material lost its adhesion below about 95% moisture content (51% solids content). Re-hydration of the dry material caused the bulk volume to double.

Bacteria, Anaerobic↗
PubMed2000

Effects of dietary fat type and level on broiler breeder performance.

The effects of added dietary fat type and level on broiler breeder performance were evaluated in two trials. In Trial 1, diets included no added fat (NAF) or 3.0% added poultry fat (PF) for individual bird energy intakes of 430 and 467 kcal/d at peak production (PCD), or 1.5% PF or 3.0% corn oil (CO) at 449 PCD. In Trial 2, diets contained NAF, 1.5 or 3.0% added CO or PF, or 3.0% lard (LA) for peak energy intakes of 463 PCD. All diets in Trial 2 were isocaloric and isonitrogenous. Feeding of experimental diets was initiated when breeders were 22 wk old in both trials, and hen BW was measured at various weeks between 22 and 47 wk in Trial 1 and between 27 and 65 wk in Trial 2. Egg production, egg weight (EW), eggshell quality, and hatchability were recorded at various weeks between 24 and 48 wk in Trial 1 and between 27 and 64 wk in Trial 2. Body weights and EW increased progressively, and eggshell quality fluctuated variably with age. Egg production peaked between Weeks 32 and 35, and hatchability was significantly depressed at Week 63. Egg weight and hatchability were not affected by dietary treatment; however, BW increased with energy level in the diet between Weeks 27 and 47. Body weight was also higher in birds fed 1.5 or 3.0% added fat compared with NAF and was higher in birds fed LA compared with CO at the 3.0% level. Egg specific gravity and shell weight per unit of surface area at Week 41 were increased by feeding low or high energy compared with moderate energy, and relative eggshell conductance was increased by using moderate compared with high energy diets and by feeding 1.5% PF compared with 3.0% PF. Egg specific gravity was increased by PF when compared with CO across fat level at Weeks 26 and 47 and by LA when compared with PF across fat level and breeder age. These data suggest that certain dietary energy and fat regimens may affect BW and eggshell quality without associated effects on EW and hatchability at various breeder ages.

Age Factors↗
PubMedDate not supplied

Hemoglobin screening in prospective blood donors: a comparison of methods.

The microhematocrit (MHCT) (MHCT) of blood obtained by ear lobe puncture (ELP) was found to be higher than that obtained by fingerstick (FS). Using copper sulfate solution to estimate hemoglobin concentration of ELP blood will lead to accepting prospective blood donors that would be rejected by fingerstick obtained samples. Raising the specific gravity of the copper sulfate solution from 1.053 to 1.055 for females and from 1.055 to 1.057 for males eliminates the discordance for males but leads to rejection of females at a high rate (20 per cent). The use of FS/MHCT to recheck those failing the gravimetric test with higher specific gravity copper sulfate is suggested. The MHCT of venous samples obtained via the needle at the conclusion of phlebotomy will be lower than the MHCT of a capillary sample obtained during screening because of a combination of : 1) hemodilution due to assumption of the recumbent position and 2) hemodilution in response to phlebotomy.

Blood Specimen Collection↗
PubMed1997

Econometric feeding and management for first cycle phase two DeKalb Delta hens.

An experiment was conducted to determine the effect of feeding method (constant vs variable) and method of formulation (lysine vs protein) on the performance and profits of first cycle, phase 2 DeKalb Delta hens from 40 to 52 wk of age as influenced by egg and feed prices. Treatments 1 to 5 were formulated based on lysine to contain 0.65 to 0.81% TSAA and fed continuously regardless of feed consumption (constant feeding). Treatments 6 to 10 and 11 to 15 were formulated based on lysine to supply 570 to 650 mg TSAA and protein to supply 580 to 660 mg TSAA per hen per d, respectively, and fed based on feed intake. Dietary TSAA level had no overall significant effect on feed consumption, egg production, egg weight, mortality, or body weight. Hens fed diets using the constant method of feeding had significantly higher egg production, egg weight, egg specific gravity, and body weight than hens fed diets formulated based on lysine or protein using the variable method of feeding. When the treatments in the two variable feeding methods were compared, feed consumption was significantly higher for hens fed diets formulated based on protein whereas egg production, egg weight, egg specific gravity, and body weight were not different. It was concluded that method of formulation (lysine vs protein) and TSAA levels required for maximum profits can vary from at least 570 to 821 mg per hen per d depending upon energy and protein cost.

Animal Feed↗
PubMed1987

Some effects of the force environment on the heart, lungs and circulation.

The data obtained in a series of human and animal experiments carried out during the last 45 years in centrifuges, specially instrumented dive bombers, and during changes in body position are the major bases for this paper. The integrated and highly effective cardiovascular reflexes which allow awake, upright humans to regain and/or maintain vision and consciousness during sustained inertial force environments several times greater than at the surface of planet Earth are particularly impressive. Multiplication of vertical gradients in interserosal pericardial, pleural, abdominal and cerebrospinal fluid pressures and/or forces in proportion, and in the resultant vectorial direction of the force environment play a critical role in this capability both in aerospace flight and everyday life on planet Earth. The differences between the near zero specific gravity of intra-alveolar gas and the (about) 1.05 value for the encompassing blood and tissue, render lung function highly susceptible to the weight determinant force environment. Creation of a womb-like environment by liquid whole-body immersion plus assisted breathing of a respirable liquid, both with specific gravities closely similar to bodily tissues, is a seemingly impractical but technologically and biologically documented expedient for allowing air breathers to endure very high sustained force and pressure environments.

Aerospace Medicine↗
PubMed1999

Effect of LF 16-0687MS, a new nonpeptide bradykinin B2 receptor antagonist, in a rat model of closed head trauma.

Bradykinin is an endogenous nonapeptide which potently dilates the cerebral vasculature and markedly increases vascular permeability. These effects are mediated by B2 receptors located on the vascular endothelium. Previous experimental studies have shown that blockade of the kallikreinkinin system, which mediates the formation of bradykinin, afforded a reduction of the brain edema that developed following a cryogenic cortical lesion. In the present study, we investigated the effect of LF 16-0687MS, a novel nonpeptide B2 receptor antagonist, on cerebral edema and neurological severity score (NSS) after closed head injury to rats. LF 16-0687MS or its vehicle (NaCl 0.9%) was continuously infused at 10, 30, and 100 microg/kg/min over 23 h starting 1 h after a focal trauma to the left hemisphere was induced using a weight-drop device. The extent of edema formation was evaluated 24 h after trauma from left and right hemispheres samples by measurement of specific gravity and water content. In a separate study, a neurological severity score based on scoring of behavioural and motor functions was evaluated 1 h and over 1 week after trauma. LF 16-0687MS at 100 microg/kg/min markedly reduced the development of brain edema as indicated by a 68% increase in specific gravity (p<0.05) and a 64% decrease of water content (p<0.05) in the left hemisphere. In addition the recovery of neurological function was significantly improved by 100 microg/kg/min LF 16-0687MS from day 3 to day 7 after CHT. In a separate experiment, we also showed that LF 16-0687MS at 100 microg/kg/min given either 1 h before or 30 min after CHT did not affect mean arterial blood pressure. These results show that blockade of bradykinin B2 receptors is an effective approach to reduce cerebral edema and to improve neurological outcome after a focal contusion to the cranium.

Animals↗
PubMed1987

The role of new vessels and macrophages in the development and resolution of edema following a cortical freeze lesion in the mouse.

The role of an influx of macrophages and neovascularity in the resolution of vasogenic edema is not well defined. The inhibition of these processes with x-irradiation or parenteral corticosteroid administration was used to evaluate their contribution to the resolution of edema around a cortical freeze lesion in mice. The resorption of Evans blue, a marker of protein extravasation, was delayed in x-irradiated mice on the second day following a freeze lesion (p = 0.0075), which correlates with a delay in macrophage infiltration around the lesion. The specific gravity of the lesion and its border regions was significantly less in x-irradiated animals on day 7 than in controls (p = 0.00062), which correlates with a delay in new vessel formation around the lesion. Administration of corticosteroids from the time of production of the freeze lesion resulted in a specific gravity significantly less than control when measured eight days after the lesion (p = 0.01). Macrophages may participate by inhibiting the development of the macromolecular portion of vasogenic edema. The development of neovascularity correlates with the resorption of the aqueous portion of vasogenic edema. As with x-irradiation, corticosteroids administered from the time of freeze lesion inhibited the resorption of the aqueous portion of vasogenic edema, but they may suppress the spread of edema in this experimental model.

Adrenal Cortex Hormones↗
PubMed1989

[The effect of the interval from dinner until retiring on the concentration of lithogenic substances during sleep].

The relationship between the interval from dinner until retiring and the concentration of various substances secreted into the urine during sleep was studied in 69 healthy men who had eaten the same meal. The specific gravity and the concentrations of creatinine, uric acid and magnesium in the morning spot urine were highest in subjects who had retired within 2 hours after dinner. The concentrations of calcium and oxalate in the morning spot urine were highest in those who had retired between 2 and 4 hours. The specific gravity and urinary concentrations of creatinine, uric acid and oxalate were markedly higher in those with the interval less than 4 hours than in those 4 hours or longer. The concentrations of calcium, magnesium and citrate were not significantly different between the two groups. From these results, we recommend that the interval from dinner until retiring be prolonged and fluid be drunk before going to bed to decrease the concentration of lithogenic substances during sleep.

Adult↗