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PubMed1985

Recirculation model following MCA occlusion in rats. Cerebral blood flow, cerebrovascular permeability, and brain edema.

A new model for establishing a successful and consistent arterial recirculation has been devised following middle cerebral artery (MCA) occlusion in the rat. A snare ligature was introduced at the stem of the MCA just distal to the lenticulostriate branches, and occlusion and recirculation were performed by pulling and releasing the thread. This method had an advantage over the use of a small clip which caused damage to the artery without good recirculation. Study of local cerebral blood flow using carbon-14 (14C)-iodoantipyrine, of cerebrovascular permeability using 14C-aminoisobutyric acid, and of brain-water content using the microgravimetric technique was performed upon recirculation following various periods of occlusion and compared with the results in permanent ischemia. A reactive hyperemia was noted within the previously ischemic area immediately upon recirculation following either a 30-minute or a 2-hour ischemic period. One or 2 hours later, delayed hypoperfusion developed in this region, but the circulation over the periphery of the ischemic area recovered well. Cerebrovascular permeability was not, however, altered during the time courses studied. Topographic changes in tissue specific gravity were compared between permanent and transient ischemia in the corresponding time-courses. Although there was a greater decrease in tissue specific gravity following recirculation when the ischemic period was maintained longer, edema formation was resolved by recirculation. Further study is required to determine thresholds of ischemic brain damage and edema formation at recirculation following focal cerebral ischemia.

Aminoisobutyric Acids↗
PubMed1999

Clinical significance and evaluation of proteinuria in NIDDM patients.

The proteinuria may reach massive proportions resulting in the nephrotic syndrome. Early and simple diagnostic may prevent further complications. Attempts are made to correlate a simple parameters like pH, specific gravity, excretion of reducing sugar and protein profile on SDS-PAGE, an advanced technique. The pH ranged between 5.7 to 9. However, specific gravity of the urine showed significant increase from 1.000 to 1.088 and has linear relation with percentage of sugar (0.2 to 2 gm) and protein banding 1 to 5 on SDS-PAGE.

Adult↗
PubMed1998

Viscosity of diluent and sensory level of subarachnoid anaesthesia achieved with tetracaine.

PURPOSE: Our objective was to evaluate the effect of viscosity in determining the cephalad spread of tetracaine administered by the subarachnoid route. METHODS: We studied 42 patients that were randomly assigned to receive subarachnoid anaesthesia for arthroscope of the knee. They received 8 mg tetracaine dissolved in either glucose 10%, sodium chloride (NaCl) 5%, glucose 5%, or NaCl 2.5%. The specific gravity and viscosity of each solvent was also measured. Cephalad spread was defined as the level of sensory block achieved. RESULTS: The specific gravity of the glucose 5% and the NaCl 2.5% solutions were similar (1.0197 +/- 0.0001 vs 1.0177 +/- 0.0001 (mean +/- SD)). That was also true for the more concentrated pair of solutions (1.0385 +/- 0.0001 for glucose 10% vs 1.0353 +/- 0.0003 in NaCl 5%). However, the viscosities of the 10% and 5% solutions of glucose (0.01178 +/- 0.0002 and 0.01020 +/- 0.0002 (g.cm-1.sec-1)) were higher (P < 0.05) than that of the other two solutions, being 0.00955 +/- 0.0001 for NaCl 5% and 0.00934 +/- 0.0002 for NaCl 2.5%. The median maximal extent of sensory block achieved was significantly higher (P < 0.05) with a solution of tetracaine in glucose 10% injected into the subarachnoid space at the L3-4 interspace than that observed in the two groups administered tetracaine in NaCl. The level of sensory block 30 min after the injection of anaesthetic was; T3 [T1-6] (median [range]) with glucose 10%, T6 [T4-10] with NaCl 5%, T5 [T2-11] with glucose 5%, and T5.5 [T2-11] with NaCl 2.5%. CONCLUSION: Viscosity was shown to be one of determinants of the clinical extent of spread of a subarachnoid anaesthetic such as tetracaine.

Adolescent↗
PubMed1997

The usefulness of diagnostic tests on pericardial fluid.

STUDY OBJECTIVES: To determine the physical, chemical, and cellular characteristics of pericardial fluid in various disease states and to assess their diagnostic accuracies. SETTING: A metropolitan university hospital. DESIGN: Consecutive case series. PATIENTS: One hundred seventy-five hospital patients, aged 1 month to 87 years, who had undergone pericardiocentesis (n = 165) or control subjects who had undergone open heart surgery (n = 10) between 1984 and 1996. MEASUREMENTS: The appearance of pericardial fluid and results of chemistry tests, cell counts, cytologic studies, Gram's stain, and microbial cultures were obtained by chart review. The etiology of each pericardial fluid sample was determined using prospective diagnostic criteria. RESULTS: Exudates differed from transudates by higher leukocyte counts and ratios of fluid to serum lactate dehydrogenase levels. Fluid glucose levels were significantly less in exudates. Sensitivity for detecting exudates was high for specific gravity > 1.015 (90%), fluid total protein > 3.0 g/dL (97%), fluid to serum protein ratio > 0.5 (96%), fluid lactate dehydrogenase ratio > 0.6 (94%), and fluid to serum glucose ratio < 1.0 (85%). None of these indicators were specific. Fluid total protein and specific gravity were moderately correlated (r = 0.56). Fluid cytologic study had a sensitivity of 92% and specificity of 100% for malignant effusion. No other test was diagnostic for a specific etiology. Among infection-associated effusions, culture-positive fluid had more neutrophils, higher lactate dehydrogenase levels, and lower ratios of fluid to serum glucose than culture-negative (parainfective) fluid. CONCLUSIONS: Evaluation of pericardial fluid might be limited to cell count, glucose, protein, and lactate dehydrogenase determinations plus bacterial culture and cytology. While not used routinely, other tests that may be highly specific for particular diseases should be ordered only to confirm a high clinical suspicion.

Adolescent↗
PubMed2006

Heat acclimatization and hydration status of American football players during initial summer workouts.

This investigation evaluated the new National Collegiate Athletic Association model of heat acclimatization for football players using physiological, psychological, fluid balance, anthropometric, and nutritional variables. Eleven football players (20 +/- 1 year, 1.88 +/- 0.05 m, and 115.36 +/- 18.85 kg) from a Division I football team were observed for the first 8 days of preseason practices. Measurements such as heart rate and gastrointestinal temperature (T(GI)) via telemetric sensor were taken before, 3 times during, and after practice daily. An average 1.39-kg (1.2%) decrease of body mass occurred from prepractice to postpractice (p < 0.01). Consistent with mild body mass losses, urinary indices of hydration status (i.e., color, specific gravity, and osmolality) indicated mild fluid deficits. A significant increase (p < 0.05) from pre- to postpractice was observed in urine color and urine specific gravity, but chronic hypohydration over the 8 days was not noted. The Environmental Symptoms Questionnaire (ESQ) postpractice score was significantly higher (p < 0.05) than the prepractice score was, but averages did not differ across practice days. There was no difference in postpractice T(GI) measurements across days (p < 0.05). Heart rate, T(GI), and ESQ measurements indicated that football players experienced gradual heat acclimatization and enhanced heat tolerance, despite progressive increases of exercise variables, clothing, and environmental stressors.

Adaptation, Physiological↗
PubMed1993

Evaluation of the Clinitek 200 urinary test-strip reader in the analysis of dog and rat urines in pre-clinical toxicology studies.

The performance of a clinical urinary test-strip reader Clinitek 200 was evaluated for dog and rat urines, in the context of pre-clinical toxicology studies. No major discrepancies were found between data generated by visual estimation or automatic measurement. Analysis of spiked samples showed good agreement between actual concentrations and Clinitek 200 responses for ketone bodies and glucose although a lack of sensitivity was found for the latter. Results for proteins showed over- or underestimation in dog and rat urines respectively at low concentrations, and overestimation at high concentrations in both species. Reproducibility of responses was excellent for ketone bodies, glucose and proteins but was weaker for haemoglobin and bilirubin. High bilirubin concentrations were found to interfere with the haemoglobin reaction. The pH measurements were found to be accurate only around pH 7. Specific gravity measurements were unreliable. Overall, the Clinitek 200 as a screening tool proved sufficiently reliable in the measurement of all parameters tested, with the exception of specific gravity.

Animals↗
PubMed1986

Brain oedema and blood-brain barrier permeability in pulsatile and nonpulsatile cardiopulmonary bypass.

In pigs subjected to pulsatile or nonpulsatile cardiopulmonary bypass (CPB) at normothermia for 3 hours, evaluation was made of water content in brain tissue (specific gravity measurements), blood-brain permeability to serum proteins (immunocytochemical demonstration of extravasated proteins, using peroxidase-antiperoxidase technique) and histopathology (paraffin sections). The specific gravity in parietal cortex was higher after pulsatile than after nonpulsatile CPB or in control pigs, the change corresponding to a 6.3% water increase. The tissue water content was unchanged in the internal capsule, basal ganglia and nucleus accumbens after CPB. The vascular permeability to serum proteins was unchanged after nonpulsatile CPB, but after pulsatile CPB minute foci of extravasated serum proteins appeared. All the animals showed dark neurons in cortical and subcortical regions, but these could have been artefacts in immersion-fixed tissue. There were no other signs of ischaemic tissue damage. The study indicated that cortical oedema may follow pulsatile CPB, the cause being altered permeability of the blood-brain barrier to serum proteins.

Animals↗
PubMed1990

The influence of condensation method on porosity and shade of body porcelain.

Condensation of porcelain is an important laboratory variable that can affect a variety of physical properties in metal ceramic restorations. This study examined four methods of condensation (brush with vibration, ultrasonic vibration, spatulation, and noncondensation) to evaluate their effects on porosity and color. Standardized 12 x 12 mm acetate plastic squares were invested and cast with Olympia alloy. After oxidation, the metal substructures received one of the following opaque and body porcelains: Ceramco II G Series, Will-Ceram V-Series, Vita VMK-68, or Jelenko. The examination of each sample consisted of three parts: (1) apparent specific gravity analysis (porosity); (2) tristimulus colorimeter analysis; and (3) subjective observer color analysis. No statistical differences (p less than or equal to 0.05) in apparent specific gravity were found between methods of condensation within any of the four porcelains. Statistical differences (p less than or equal to 0.05) in color were noted between methods of condensation within several of the porcelains by both the tristimulus colorimeter and the subjective observers.

Analysis of Variance↗
PubMed1990

Blood and urinary profiles of free-ranging desert mule deer in Arizona.

As a corollary to a more comprehensive study on their ecology, we documented blood and urinary profiles for 10 free-ranging desert mule deer (Odocoileus hemionus crooki) (five males, five females) captured by net-gun shot from a helicopter during February 1988 in Saguaro National Monument, Arizona. Pursuit with the helicopter for netting deer ranged from 3 to 15 min. Blood profiles included seven hematological characteristics and 12 serum chemistries, electrolytes, hormones and enzymes. Urine samples were assayed for urea nitrogen, creatinine, sodium, potassium, calcium and phosphorus. Urinary data were compared as ratios to creatinine. Serum cholesterol was greater (P less than 0.05) in males than females. Pursuit time was correlated with serum non-esterified fatty acids (r = 0.67, P less than 0.05) and influenced urinary specific gravity (r2 = 0.77, P less than 0.004), urea nitrogen: creatinine (r2 = 0.79, P less than 0.005), and potassium: creatinine (r2 = 0.42, P = 0.08) ratios. Increasing specific gravity was related to urinary creatinine concentration (r2 = 0.72, P less than 0.008). All deer exhibited acute adrenal stimulation, accompanied by elevated serum creatine phosphokinase and urinary potassium: creatinine ratios, which were indicative of acute excitement and muscle trauma associated with the capture process. We demonstrated that urinary data are a valuable supplement to serum data in demonstrating effects of intense physical exertion, and both forms of data emphasize the need to assess capture-related excitability as a source of variation in blood and urine characteristics of free-ranging desert mule deer.

Animals↗
PubMed1991

Effect of time of cisplatin administration on its toxicity and pharmacokinetics in dogs.

Cisplatin (90 mg/m2) was administered in a 5-minute bolus IV infusion to dogs at 8 AM (n = 6) or 4 PM (n = 6). Blood and urine samples were collected over a 4-hour period for statistical moment pharmacokinetic analysis. Mean urinary excretion rate of total platinum was increased, whereas mean plasma residence time of ultrafilterable platinum was decreased, in the group treated at 4 PM (PM group), compared with those treated at 8 AM (AM group). Over a 2-week postinfusion-monitoring period, both groups of dogs developed decreases in creatinine clearance, urine/serum osmolality ratio (UOsm/SOsm), specific gravity, and increase in BUN, serum creatinine concentration, urine gamma-glutamyltranspeptidase/urine creatinine ratio (UGGT/UCr), fractional excretion of magnesium, and fractional excretion of phosphate. Urine specific gravity and UOsm/SOsm were significantly decreased, whereas UGGT/UCr and BUN were significantly increased in the AM group, compared with the PM group. The time of administration had a significant effect on the pharmacokinetics of cisplatin, which resulted in significant differences in cisplatin-induced renal toxicosis.

Animals↗
PubMed1998

[Spread of spinal anesthesia with 3 different hyperbaric solutions used in Japan].

We studied the spread of spinal anesthesia with 3 different hyperbaric solutions commercially available in Japan. Percamin-S [0.3% dibucaine in 5% hyperbaric saline] (P), Neo-Percamin.S [0.24% dibucaine with 0.12% T-caine in 9.5% glucose] (N) and 0.5% Tetcaine [tetracaine] in 10% glucose (T) were studied. Two ml of each solution was administered intrathecally using a 25 gauge Quincke needle. Patients (n = 90) were allocated to one of 9 groups receiving 2 ml of P, N or T at L 2-3, L 3-4 or L 4-5 interspace. Both N and T produced significantly higher spread of analgesia than P at any of L 3-4 and L 4-5 interspaces. P and N have the same specific gravity, even though significant differences were found in spread of segmental analgesia. Local anesthesic agents and solvent solutions themselves are considered to influence the spread of spinal anesthesia as the specific gravity of hyperbaric solution does.

Adult↗
PubMed1982

Evaluation of periventricular hypodensity in experimental hydrocephalus by metrizamide CT ventriculography.

Hydrocephalus was induced in 13 dogs by injecting kaolin into the cisterna magna and was evaluated by computerized tomography (CT) scans. Modification of periventricular hypodensity was observed by metrizamide-enhanced CT ventriculography. Periventricular hypodensity was seen as early as 12 hours after kaolin injection. On CT ventriculography, metrizamide stayed longer in the ventricles of hydrocephalic dogs than in those of normal dogs, and migrated into the areas of periventricular hypodensity; the changes became significant within 12 to 24 hours. Four of the dogs were killed immediately after CT ventriculography, and the iodine concentration was measured. Iodine concentration was highest in the periventricular white matter, followed by the basal ganglia, and it was low in the cerebral and cerebellar cortex. When the change in Hounsfield units found by CT ventriculography at the regions of interest was compared to the actual iodine concentrations, the figures were quite compatible. Similarly, the specific gravity was measured in tissue from various parts of the brain of two hydrocephalic dogs, and compared against the value of that from five normal dogs. The specific gravity values were particularly low in the periventricular white matter of the hydrocephalic brains, suggesting a higher water content in that region. Since the increased migration of metrizamide occurred at the same region, it is suggested that development of periventricular hypodensity is due to increased transit of cerebrospinal fluid from the ventricles to the white matter.

Animals↗
PubMed1977

The dipsogenic effect of alcohol and the loss of control phenomenon.

A counterbalanced within-subjects design was employed to assess the acute effects of alcohol ingestion on thirst and fluid intake and to relate these effects to the dehydration known to result from acute ingestion of alcohol. Fourteen male nonalcoholic social drinkers between the ages of 18 and 30 consumed 0.8 gm of alcohol/kg body weight during one experimental session and a placebo (0.05 gm/kg) of equal volume during the other. During the 90-minute drinking period and for one hour both before and afterward, urine specimens were collected. After the drinking period, blood alcohol levels and unobstrusive measures of ad lib drinking were recorded. In addition, subjects rated their degree of thirst three times during each session. Analyses of variance indicated that alcohol significantly increased both fluid intake and urine output, and decreased urine specific gravity. Moreover, thirst ratings were also significantly greater after alcohol than after placebo and fluid intake after alcohol was significantly correlated with prior measures of fluid balance, mean urine specific gravity, peak blood alcohol level and thirst. The implications of these results for the loss of control in alcoholism are discussed and a new theoretical account of the phenomenon is proposed.

Adult↗
PubMed1997

Detection of lipid peroxidation and hydroxyl radicals in brain contusion of rats.

To examine the relationship between the free radicals and brain tissue damage, we investigated the intensity of brain hydroxyl (OH) radical generation and lipid peroxidation in the rat contusion injury model. A unilateral contusion was induced by a weight-drop method. All rats were decapitated six hours after the injury, and brain samples were taken from three portions (core, peripheral, and distal) to examine the specific gravity as an indicator of brain edema, generation of OH using an electron paramagnetic resonance spectrometer (EPR), and malondialdehyde (MDA) and 4-hydroxyalkenals production. Analysis of the specific gravity revealed cerebral edema on the ipsilateral side in the injured group. The signal intensity of EPR in the core and peripheral portions in the contusion group was significantly higher than that in the distal portion of the contusion group and that of all portions in the control animals. No significant difference was observed between the core and peripheral portions of the contusion group. The MDA and 4-hydroxyalkenals production was significantly higher in the core and peripheral portions than in the distal portion of the contusion group and that of all portions of the control group. The degree of posttraumatic brain edema was closely correlated with the increase of DMPO-OH adduct, MDA, and 4-hydroxyalkenals. These results support the current concept that free radical production following traumatic brain injury may induce lipid peroxidation and may be the direct cause of edema formation.

Animals↗
PubMed2002

The defined HHS/DOT substituted urine criteria validated through a controlled hydration study.

This controlled hydration study was designed to validate the substitution criteria used by the Substance Abuse and Mental Health Services Administration (SAMHSA) to classify a workplace urine specimen as inconsistent with normal human urine. Study participants (n = 56) ingested at least 80 oz (2370 mL) of fluid over a 6-h period, 40 oz during the first 3 h (DOT hydration protocol) and 40 oz during the second 3-h period. Urine specimens (n = 498) were collected upon awakening, just prior to hydration, at the end of each hour of the 6-h test period, and upon awakening the next day. No urine specimen satisfied the paired substitution criteria of urine creatinine < or = 5.0 mg/dL and specific gravity < or = 1.001 or > or = 1.020. Seventy-three percent of the participants produced at least one specimen meeting the criteria for dilute urine: urine creatinine < 20.0 mg/dL and specific gravity < 1.003. Fifty-five percent of the participants produced at least one dilute urine specimen during the first 3 h of hydration. In conclusion, this controlled hydration study supports the criteria set by SAMHSA for classifying a specimen as substituted (inconsistent with normal human urine).

Adult↗
PubMed1991

Comparison of the effects of synthetic and natural zeolite on laying hen and broiler chicken performance.

Three experiments were conducted to investigate the effect of zeolites on laying hens (Experiments 1 and 2) and broiler chickens (Experiment 3). Each experiment used corn and soybean meal-based practical diets. Experiment 1 was a 90-day trial and used 200 40-wk-old laying hens. The basal diet contained 2.75% calcium and .7% total phosphorus. The dietary treatments were the basal diet and the basal diet plus 1.5% synthetic zeolite (SZ; Ethacal). Experiment 2 was a 56-day trial and used 360 36-wk-old laying hens. The dietary treatments were .12, .22, .32, and .42% nonphytin phosphorus with and without 1.0% SZ and 1.0% natural zeolite (NZ; Zar-Min). All diets contained 3.5% calcium. Experiment 3 utilized 240 broiler cockerels from 1 to 16 days. The dietary treatments were two calcium levels (.65 and 1.0%) with and without 1.0% supplementary SZ and NZ. In Experiment 1, egg specific gravity was significantly increased with SZ supplementation. Egg weight and egg production were unaffected. Phytin phosphorus retention and plasma dialyzable phosphorus were significantly reduced by SZ. In Experiment 2, egg specific gravity was not affected by SZ or NZ. Egg weight, egg production, plasma dialyzable phosphorus, and the retention of phosphorus and phytin phosphorus were significantly reduced by SZ with the effect on egg weight and egg production being the most severe at the lower levels of dietary nonphytin phosphorus. Natural zeolite had no effect on egg weight, egg production, plasma calcium, plasma phosphorus, or on the retention of calcium, phosphorus, and phytin phosphorus. In Experiment 3, weight gain and percentage tibia bone ash were significantly reduced by SZ. The SZ had no effect on the incidence and severity of tibial dyschondroplasia. Weight gain, feed efficiency, and the incidence and severity of tibial dyschondroplasia were significantly reduced and the percentage bone ash significantly increased by 1.0% calcium. Natural zeolite significantly improved feed efficiency and had no effect on any other parameter measured.

Aluminum Silicates↗
PubMed1982

An improved gravimetric measure of cerebral edema.

Significant errors are introduced into the measurement of brain tissue water by the specific gravity technique when the edema fluid contains protein. Protein adds to the tissue solids, increasing the density of the tissue, and masks the proportional increase of brain water. Existing equations relating measured specific gravity and tissue water are not applicable, and a new formula was developed that compensates for the protein component of edema and reduces the experimental error. The new method was applied to the measurement of tissue water in cat brain made edematous by direct infusion of fluids of known composition and volume to test the theory. This technique for improving the gravimetric assessment of brain edema is presented.

Animals↗
PubMed1998

Influence of hypoglycemic coma on brain water and osmolality.

To study the effects of pronounced hypoglycemia on brain osmolality and brain edema formation, fasted rats were rendered hypoglycemic by injection of insulin, and subjected to 30 min of hypoglycemic coma. Recovery was accomplished by glucose administration. The change in water content in different brain regions was measured as a change in specific gravity after 30 min of hypoglycemic coma, or 30, 60, and 180 min after glucose administration. Plasma and brain tissue osmolality were measured in separate animals. The results show a significant decrease in specific gravity (increase in water content) in all structures measured (caudoputamen, neocortex, hippocampus, and cerebellum) at the end of the period of coma, as well as after 30 min and 60 min of recovery. At 180 min of recovery, brain water was normalized. The edema affected all structures to the same degree regardless of their vulnerability to hypoglycemic damage. Brain tissue osmolality showed a tendency to decrease with decreasing tissue glucose content. The decrease was significant (P<0.01) at 30 min of isoelectric coma. In the recovery phase, normal brain osmolality was restored within 30 min. Measurements of blood-brain barrier (BBB) permeability after 30 min of hypoglycemic coma showed no extravasation of Evan's blue, though a small but significant increase in the permeability for aminoisobutyric acid (AIB) in caudoputamen and in cerebellum was found. To analyze the importance of tissue acidosis for formation of edema, hypoglycemic animals were made acidotic by increasing the CO2 concentration in inspired air to produce an arterial plasma pH of 6.8-6.9. In these animals the edema was of a similar degree to the normocapnic animals, and the permeability for AIB was normal. We conclude that osmolytic mechanisms are not the primary cause of the selective neuronal vulnerability in hypoglycemic coma. Furthermore, the BBB is largely intact during a hypoglycemic insult.

Acidosis↗