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At least 955 records · Page 53Linked to original sources
PubMed1998

Mechanisms of increased intracranial pressure in rabbits exposed to head-down tilt.

Changes in intracranial pressure (ICP) resulting from head-down tilt (HDT) were studied in rabbits, and a possible role of edema formation in the change of ICP was examined. Animals were anesthetized with pentobarbital sodium and artificially ventilated. ICP was continuously monitored through a catheter inserted into the subarachnoid space. It increased depending on the tilt angle and decreased when the tilt angle was reduced. ICP elevated from 4.6 +/- 0.7 mmHg (mean +/- standard error of the mean) at horizontal prone position to 13.7 +/- 1.0 mmHg immediately after the onset of 45 degrees HDT and gradually reduced toward the pre-HDT baseline in the next 8 h. ICP decreased below the pre-HDT baseline value immediately after returning to the horizontal prone position, and gradually increased toward the baseline during the 2 h of recovery period. Histological examination (HE stain) demonstrated that exposure to 8 h of HDT did not cause remarkable edema in either the gray matter or the white matter in rabbits. Water content and specific gravity of brain tissues both were increased in the HDT group in comparison with the control group. These results suggest that edema formation plays little role in the elevation of ICP during the acute phase of HDT in rabbits.

Animals↗
PubMed1975

Incidence and range of microscopic hematuria in patients with indwelling urinary catheters.

The presence and number of red blood cells (RBCs) in the urine after catheterization were ascertained in 40 patients without urinary tract pathology or other cause for hematuria. Before catheterization, 90% of the patients had less than or equal to 1 RBC/high power field (HPF), a figure similar to that for normal volunteers. Two days after catheterization, however, 61,5% of the patients had 2 RBC/HPF with a range between zero and "too numerous to count." The incidence of "hematuria" (greater than or equal to 2 RBC/HPF) declined with time. Neither urinary specific gravity nor urinary tract infection could be correlated with hematuria. At any time after catheterization, 90% of the patients had greater than or equal to 50 RBC/HPF. These data may be helpful in differentiating hematuria caused by the catheter from that due to drug reactions or disease states.

Adult↗
PubMed2001

[Urine fibrinolytic activity as an indicator of kidney damage in uric acid metabolic imbalance].

AIM: To determine functional fibrinolytic activity of the urine in patients with different forms of purine metabolism disorder. MATERIAL AND METHODS: Uricemia, 24-h uricosuria, serum creatinine, GFR, maximal urinary specific gravity, urokinase activity in the urine, total fibrinolytic activity of the urine (TFAU), activity of plasminogen activator inhibitor (PAI) in blood were studied in 33 patients with genetically determined purine metabolism disorders. RESULTS: Patients with purine metabolism disorders vs controls had decreased TFAU and urokinase activity. There was no significant difference between the study and control groups in the levels of PAI in blood. No statistically significant difference was found between the patients with hyperuricemia and patients with hyperuricosuria in the levels of TFAU and urokinase activity, while the group with hyperuricemia was characterized by a decreased maximal specific urinary gravity. CONCLUSION: A decrease in TFAU and urokinase activity in patients with purine metabolism disorder was observed in the isolated hyperuricosuric stage of urite renal damage.

Adolescent↗
PubMedDate not supplied

Evaluation of urine gamma-glutamyl transpeptidase-to-creatinine ratio as a diagnostic tool in an experimental model of aminoglycoside-induced acute renal failure in the dog.

The potential diagnostic utility of the urine gamma-glutamyl transpeptidase (GGT)-to-creatinine ratio was evaluated in an experimental canine model of aminoglycoside-induced nephrotoxicity. A therapeutic dosage of gentamicin resulted in a twofold increase in the mean urine GGT-to-creatinine ratio that was not associated with clinically significant nephrotoxicity. In dogs each given a nephrotoxic dosage of gentamicin, an increase in mean urine GGT-to-creatinine ratios approximately three times baseline values preceded clinically significant abnormalities in serum creatinine, urine specific gravity, and urine protein-to-creatinine ratio. The urine GGT-to-creatinine ratio appears superior as an early indicator of aminoglycoside-induced nephrotoxicity. Further studies in canine clinical cases are warranted.

Acute Kidney Injury↗
PubMed1992

Lidocaine 0.5% spinal anaesthesia: a hypobaric solution for short-stay perirectal surgery.

The efficacy of subarachnoid injection of 8 ml lidocaine 0.5% was assessed in ten outpatients having perirectal surgery in the jackknife position. This solution is hypobaric, with a baricity 0.9985 +/- 0.0003 (mean +/- SD). Injections were made with the patient in the surgical position (with the upper torso at a 15 degrees downward inclination). Sensory level was tested by pinprick. Times to two-segment regression, to complete resolution of sensory analgesia, to urination, and to discharge from the recovery room were recorded. All injections produced effective anaesthesia for surgery. Lidocaine 0.5% behaves clinically as a hypobaric solution. Dermatomal levels remained low (T11 to L5) while the patients were in the surgical position (head down), but rose two to six dermatomes if the patient's head was elevated after surgery. Time to two-segment regression was 97 +/- 36 min, time until regression to S1 was 116 +/- 22 min, time to complete resolution of sensory blockade was 151 +/- 23 min, time to urination was 197 +/- 64 min, and time to discharge from the recovery room was 205 +/- 45 min. Lidocaine 0.5% provides effective spinal anaesthesia of short duration appropriate for outpatient surgical procedures. Dermatomal sensory spread of anaesthesia, and our measurements of specific gravity, indicate that this solution is hypobaric. It appears that changes in position can alter the spread of analgesia for at least one hour after injection and, thus, we caution against elevating the patient's head in the immediate postoperative period.

Adult↗
PubMed1976

The edema of cerebral contusion.

A model is described for study of the cerebral edema associated with the contusion of closed head injury. A Remington Humane Stunner was used to deliver blows to the skulls of anesthetized cats. Forty-eight hours after impact, those cats demonstrating a one-sided contusion were tested for cerebral edema by measurement of the decrease in density (specific gravity) of white matter from normal values. Significant change in tissue density was seen in the white matter of contused hemispheres. Hemispheres with contusion limited to the cortex (gray matter) showed a change in tissue density which was considerably less than that seen in hemispheres with contusion involving both gray and white matter.

Animals↗
PubMed2005

Modified sugar centrifugal flotation technique for recovering Echinococcus multilocularis eggs from soil.

Among soil-transmitted parasitic diseases, alveolar hydatidosis due to the ingestion of Echinococcus multilocularis eggs is becoming a serious problem in Hokkaido, the northern most island of Japan. Dissemination of the infection far from the endemic areas can occur if motor vehicles transmit soil contaminated with eggs. No appropriate and validated method for recovering the taeniid eggs from soil is available. A modified sugar centrifugal flotation technique, using a sucrose solution of specific gravity 1.27 and 0.05% Tween-80, was evaluated as a method to successfully recover eggs from soil. Contamination levels as low as 10 eggs per gram could be detected. This method may be useful to determine the prevalence of E. multilocularis, its transmission, and the potential for by monitoring soil contamination with eggs.

Animals↗
PubMedDate not supplied

Studies on ageing in Turbatrix aceti.

Morphologic and physiologic changes which occur during senescence in the free-living nematode Turbatrix aceti are described. With age areas of the interchordal hypodermis containing nerve elements thickened, electron-dense aggregates formed within the pseudocoelom and age pigment granules accumulated within the intestinal epithelium. Specific gravity did not change with age. Old nematodes which had reproduced showed increased osmotic fragility, but this change was not observed in virgin females. The parameters characterizing senescence in T. aceti are compared with those of Caenorhabditis briggsae, another nematode being used as a model to study biological ageing.

Aging↗
PubMed1991

Effect of chemical sympathectomy on cerebral blood flow in rats.

Thirty male Wistar rats, weighing 350 to 400 gm each, received stereotactic injections of 6-hydroxydopamine (300 micrograms/kg) into the left lateral ventricle. The same amount of saline was injected into a control group of 15 rats. Seven days after this procedure, cerebral blood flow (CBF) was measured by the hydrogen clearance method. A hypertensive condition at a mean arterial pressure of about 160 mm Hg was maintained for 1 hour by intravenous infusion of phenylephrine. In the 6-hydroxydopamine-treated group, CBF increased significantly after the elevation of systemic blood pressure compared with that in the control group, and cerebral autoregulation was impaired. After a 1-hour study, the specific gravity of the cerebral tissue in the treated group significantly decreased; electron microscopic studies at that time revealed brain edema. It is suggested that depletion of brain noradrenaline levels causes a disturbance in cerebral microvascular tone and renders the cerebral blood vessels more vulnerable to hypertension.

Animals↗
PubMed1975

Isosmolar coma during parenteral alimentation with protein hydrolysate in excess of 4 gm/kg/day.

Isosmolar coma occurred during the first week of parenteral nutrition in four infants when the amount of protein hydrolysate infused was rapidly increased to or above 4 gm/kg/day. Coma developed within a 6- to 12-hour period and was characterized by (1) a normal serum osmolality, (2) an elevated urine specific gravity, and (3) the rapid reversal of the clinical signs when the protein containing solution was discontinued. A very gradual increase in protein content to a total of no more than 4 gm/kg/day is advised to provide an adequate yet safe protein load for intravenous nutrition.

Ammonia↗
PubMed1992

Research note: effect of removing salt from the diet of broiler breeder hens.

Two 28-day experiments were conducted utilizing 75-wk-old Arbor Acres broiler breeder hens to determine the effect of removing salt from the diet. Birds in Experiment 2 had been force-rested at 60 wk of age but were in production (65% hen-day) at experiment initiation. All hens received a corn-soybean meal diet either with or without added salt. Egg production was significantly reduced in both experiments by the end of the 4th wk for birds fed the diet with no added salt. However, egg production did not cease in hens receiving the diet with no added salt. Egg weights from hens receiving the diet with no added salt were significantly reduced by the end of Week 2 in Experiment 1 and Week 3 in Experiment 2. Specific gravity was only intermittently affected by dietary salt removal. Birds receiving no added salt lost 541 and 580 g in Experiments 1 and 2, respectively. Birds receiving added salt diets gained 55 and 23 g in Experiments 1 and 2, respectively. Removing salt from the diet was not an acceptable method of force-resting broiler breeder hens.

Animal Feed↗
PubMed1982

Aqueous vasopressin response test in clinically normal dogs undergoing water diuresis: technique and results.

Studies were undertaken to develop a standard procedure and to establish reference values for an aqueous vasopressin response test in dogs with normal renal function undergoing water diuresis. After IV administration of 5 mU of aqueous antidiuretic hormone (ADH)/0.45 kg of body weight of 13 water-loaded clinically normal dogs, the mean urine specific gravity increased from 1.002 +/- 0.001 to 1.021 +/- 0.0058; the mean urine osmolality increased form 99 +/- 52 mOsm/kg of water to 933 +/- 252 mOsm/kg. The PCV, total plasma protein concentrations, and serum osmolalities decreased in all dogs during water loading and ADH administration, but slowly returned toward base-line values after discontinuing the ADH infusion.

Animals↗
PubMed1993

Neuronal-glial exchange of taurine during hypo-osmotic stress: a combined immunocytochemical and biochemical analysis in rat cerebellar cortex.

Rat cerebellar Purkinje cells show a high level of taurine-like immunoreactivity. Light-microscopic immunocytochemistry indicated that the level of taurine in these cells was substantially decreased in animals that had survived for 4 h after an intraperitoneal injection of distilled water. This treatment resulted in a 15-20% reduction in plasma osmolality. The changes in the Purkinje cells were accompanied by an increased immunolabeling of neighboring glial cells (Golgi epithelial cells). The changes in both cell types were reversed in animals whose plasma osmolality had been normalized by injections of hypertonic saline 4 h after the water loading. Adjacent sections incubated with a GABA antiserum did not exhibit any overt changes in response to the hypo-osmotic stress. Quantitative electron-microscopic analysis of ultrathin sections subjected to postembedding immunogold cytochemistry indicated that the Purkinje cells had lost 50-60% of their taurine contents after water loading and that the loss affected all intracellular compartments, including mitochondria and cytoplasmic matrix. The loss of taurine immunoreactivity from Purkinje cells was accompanied by an estimated 70-80% increase in the contents of immunoreactive taurine in adjacent glial cells. Biochemical recordings of tissue amino acids in a parallel series of animals revealed a 12% reduction in cerebellar taurine contents 4 h after water loading (value corrected for changes in specific gravity). This reduction had progressed to 32% after 8 h and was only partly prevented by normalization of plasma osmolality. The tissue levels of GABA and several other amino acids showed a decrease similar to that of taurine, while glutamine displayed a considerable increase after water loading. Our findings indicate that acute reductions in plasma osmolality cause a flux of taurine from Purkinje cells to glia, and that this flux is reversed upon normalization of plasma osmolality. These changes are superimposed on a decrease in the biochemically recorded tissue level of taurine. Unlike the cellular redistribution, this decrease was not reversible within the time frame of the present study, and it was not specific for taurine. Cellular redistribution of taurine may represent a rapid adjustment to osmotic perturbations in vivo. In addition, it may reflect a higher priority for neuronal compared with glial volume regulation.

Amino Acids↗
PubMed1993

Shy-Drager syndrome with abnormal circadian rhythm of plasma antidiuretic hormone secretion and urinary excretion.

A 67-year-old patient with Shy-Drager syndrome (SDS), exhibited nocturnal polyuria associated with abnormal circadian rhythm of antidiuretic hormone (ADH) secretion and nocturnal polyuria. The patient excreted a larger volume of urine during the nighttime compared to that in the daytime. The specific gravity of urine at night was lower than that during the day. In contrast to normal circadian rhythm of ADH, the patient's plasma concentration of ADH was increased in the daytime. The present study raised the possibility that an altered circadian rhythm of plasma ADH secretion might be considered a result of the neurodegenerative changes involving the hypothalamus.

Aged↗
PubMed2002

Evaluation of urinalysis as an aid in the diagnosis of equine grass sickness.

To determine whether urinalysis can aid the diagnosis of equine grass sickness, samples of urine from 15 horses with acute grass sickness, eight horses with subacute grass sickness, 17 co-grazing horses and 17 stabled control horses were analysed. The samples from all of the horses with grass sickness had a significantly higher specific gravity, higher protein and creatinine concentrations and a significantly lower pH; the samples from the horses with acute grass sickness also had significantly higher glucose concentrations. These differences may support a diagnosis of grass sickness but they are not pathognomonic for the disease.

Acid-Base Equilibrium↗
PubMed1978

[Measurement of human body fat by means of gravimetry. Application of Archimedes' principle].

The weighing of the human body under water is an application of Archimedes' law. Fat being lighter than water or than the structures of lean body mass, body fat can be measured by determining the specific gravity of the human body; that is, by underwater weighing. Body fat has been determined in an "ideal" sample of 14 men and 23 women, all aged 20 years. Testing against a reference measure of body fat makes it possible to test the validity of some anthropometric measurements and of some indices of obesity. These indices offer no advantages over anthropometric measurements.

Adipose Tissue↗
PubMed1987

Mass, volume and dimensional distributions in biology, with special reference to cells.

The positively skewed distribution of mass (weight) in biology was examined, and it was concluded all weight or masses can best be described by lognormal theory. Examples are given ranging in weight from viruses to humans. The accretion of mass proceeds as "more of the same" and primarily does not alter function. Immunologic properties must be carefully preserved. Small biologic entities can afford only small mass gains or losses while preserving their functionality; the larger the entity, the larger is the variability of mass functionally permitted. A well-established, convenient graphic method of analyzing a sample is described, with the advantages and pitfalls discussed. At the cellular level, volume and dimensions are lognormally distributed whenever the specific gravity (g/cu cm) is nearly homogenous among the particles or cells. In multicellular organisms, dimensions and forms (such as height and cranial circumference) are primarily the product of multifactorial genetic determinants and frequently appear as normal distributions. This paper discusses the meaning of the law of proportionate effects for small biologic objects, especially cells, and how an initial or "elementary" distribution may be conceived.

Animals↗
PubMed1980

Separation of human spermatozoa from a single ejaculate into various age-groups.

Ejaculated human spermatozoa were separated into various age-groups on the basis of their different specific gravity. Salt-poor 25% human serum albumin was used as a separation medium. The separation process had no detectable harmful effect on the spermatozoa. The motility and penetration abilities of the separated cell fractions were tested by means of a new method using a fragiligraph. The younger group of spermatozoa demonstrated better motility and penetration ability in comparison with the older age-groups.

Adult↗