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PubMed2004

Effect of probiotic supplementation on laying hen diets on yield performance and serum and egg yolk cholesterol.

The effects of dietary supplementation of a commercial probiotic (BioPlus 2B) on daily feed consumption, egg yield, egg weight, specific gravity, body weight, feed conversion ratio, serum and egg yolk cholesterol, and serum trigylceride in layer hens were investigated. In 12 replicates, 480 27-week-old Brown-Nick layers were fed with diets containing 0, 250, 500 or 750 mg kg(-1) probiotic for 90 days. When compared with the controls, supplementation of 250, 500 and 750 mg kg(-1) probiotic increased egg production, but decreased the damaged egg ratio (p < 0.05), egg yolk cholesterol and serum cholesterol (p < 0.001) levels. In addition, serum triglyceride levels were reduced by using 500 and 750 mg kg(-1) probiotic supplementation (p < 0.001). Feed conversion ratios were positively affected by supplementation of 250 and 500 mg kg(-1) probiotic compared with controls (p < 0.05). There was no statistically significant difference between the control and all treatment groups on feed consumption, egg weight, specific gravity, body weight, and egg yolk weight.

Animal Feed↗
PubMed1989

Diagnostic parasitology.

Diagnosis of parasitic infections in small animals is challenging, interesting, and fun, and involves the recognition of parasite stages based on size, morphology, color, and movement. Size and morphology are the major diagnostic parameters, and a calibrated microscope is the essential tool in the diagnostic laboratory. The fecal flotation technique is used routinely for the diagnosis of most parasites that reside within the gastrointestinal tract. The specific gravity and type of solution used often will influence the results obtained. A sugar flotation solution with a specific gravity of 1.27 is one that will float a majority of parasite stages with minimal distortion. Other techniques for diagnosis of specific gastrointestinal parasites include the direct smear and the merthiolate-iodine-formalin preservative method for diagnosis of Giardia sp, the Baermann technique for diagnosis of lungworm and other live larvae, the direct sedimentation technique for diagnosis of trematode eggs, the ether-formalin-sedimentation technique for diagnosis of trematode eggs and concentrating protozoan cysts from feces with high fat content, and the McMaster technique, a dilution modification of the fecal flotation technique. Techniques for evaluation of parasites in blood include the Knott's test, hematocrit method, and direct blood smear for diagnosis of microfilariae and thick and thin stained blood smears for diagnosis of Babesia sp, Haemobartonella sp, Cytauxzoon felis, Hepatozoon canis, and Trypanosoma cruzi. Tissue impression smears are used commonly for the diagnosis of Leishmania sp in dogs and biopsy specimens or aspirates are used for the diagnosis of Pneumocystis carinii. Diagnosis of acute toxoplasmosis can be accomplished with peritoneal and thoracic fluids, and organisms occasionally are detected in blood or spinal fluid. Serological tests for many parasitic diseases have been developed and often are used as supportive diagnostic tests.

Animals↗
PubMed2004

Tolerance to pentylentetrazol-induced convulsions and protection of cerebrovascular integrity by chronic nicotine.

The authors' previous studies have shown that in nicotine-induced seizures sensitivity was decreased and blood-brain barrier (BBB) disruption was prevented as a consequence of nicotine pretreatment. This study aimed to investigate the possible protective actions of nicotine on cerebrovascular permeability and seizures induced by pentylentetrazol (PTZ) injection. Cerebrovascular effects of nicotine were evaluated by measuring the permeability changes of BBB using Evans-Blue (EB) dye and specific gravity (SG), which indicates brain water and protein content. The experiments were carried out on Wistar rats. Animals were randomly divided into two groups. Convulsions were induced by injection of PTZ (80 mg/kg i.v.) in rats either pretreated with nicotine daily with a low dose of 0.8 mg/kg day for 21 days or injected with a single dose of 6 mg/kg mecamylamine. The same procedures were followed in control rats with the exception that they were injected only with saline. PTZ injection caused tonic-clonic convulsions and increased the EB dye leakage and specific gravity values in saline-injected control rat brains. Daily injection of nicotine lessened the intensity of seizures. These were accompanied by marked decreases in both the leakage of EB and brain water content. Acute administration of a nAChR antagonist mecamylamine significantly increased seizure latency and decreased the duration of seizures. Thereby, mecamylamine reduced the EB leakage and water content in most brain regions. These results indicate that development of tolerance to PTZ convulsions can be produced by chronic nicotine administration in rats. The mechanism for this effect currently needs clarification. Moreover, the data also suggest that cholinergic activity may account for occurrence of PTZ-induced convulsions.

Analysis of Variance↗
PubMed1993

A reassessment of the importance of "low-count" bacteriuria in young women with acute urinary symptoms.

OBJECTIVE: To determine whether a statistical association exists between "low-count" bacteriuria (> 10(2) to 10(4) colony-forming units/mL) and acute urinary symptoms in young women. DESIGN: Prospective, case-control study. SETTING: Gynecology clinic at a student health center. PATIENTS: Women with or without urinary or vaginal symptoms. MEASUREMENTS: History of urinary infections and sexual activity. Quantitative determination of bacteriuria and pyuria and bacterial species; urine leukocyte esterase test; specific gravity; creatinine levels; vaginal leukocytes; and in-vitro culture of urine. RESULTS: The frequency of recent sexual activity, pregnancies, and contraceptive practices was not statistically different between women with acute urinary symptoms and asymptomatic controls. Escherichia coli and Staphylococcus saprophyticus were the only microorganisms statistically associated with urinary symptoms and pyuria (P < 0.001). Low counts of these organisms were found in 10.2% of asymptomatic women. As the bacterial count increased, the association between these organisms and symptoms increased, and a step-wise increase occurred in the frequency and magnitude of pyuria, but the specific gravity and urine creatinine levels remained unchanged. Escherichia coli, even at low counts, grew well in the patients' own urine. Pyuria (> 20 leukocytes/mm3) was present in 19.6% of asymptomatic women and was associated with vaginal leukorrhea. CONCLUSIONS: "Low-count" bacteriuria was statistically more frequent among young women with urinary symptoms than among asymptomatic controls. The low counts could not be explained by dilution of the urine or failure of the bacteria to grow well in the patients' urine. These findings suggest that the infection was not established in the bladder urine and that "low-count" bacteriuria might be an early phase of urinary tract infection.

Acute Disease↗
PubMed1975

Iowa wrestling study: changes in the urinary profiles of wrestlers prior to and after competition.

During the 1973 and 1974 state high school wrestling championships, urine samples were obtained from wrestlers prior to the weigh-in, immediately before they wrestled, and immediately after the subjects had completed their match. Specific gravity, osmolarity, pH, sodium and potassium determinations, as well as qualitative tests for protein and ketones, indicated that the wrestlers were in a dehydrated state at the time of weigh-in. After the five hour interim between the weigh-in and the first match, all but the pH measure remained essentially unchanged. This absence of significant changes in the urinary profile suggests that the wrestlers were unable to rehydrate during the five hour time period between the weigh-in and the first match and that they were competing in a dehydrated state. Urine samples collected after competition were significantly lower in specific gravity, osmolarity and potassium concentration than samples obtained before the match. The urinary potassium levels were of interest because at the three conditions (weigh-in, before the first match, after competition) they were 73-182% higher than values reported for high school students who were nonwrestlers.

Dehydration↗
PubMed2003

Settling characteristics of nursery pig manure and nutrient estimation by the hydrometer method.

The hydrometer method to measure manure specific gravity and subsequently relate it to manure nutrient contents was examined in this study. It was found that this method might be improved in estimation accuracy if only manure from a single growth stage of pigs was used (e.g., nursery pig manure used here). The total solids (TS) content of the test manure was well correlated with the total nitrogen (TN) and total phosphorus (TP) concentrations in the manure, with highly significant correlation coefficients of 0.9944 and 0.9873, respectively. Also observed were good linear correlations between the TN and TP contents and the manure specific gravity (correlation coefficients: 0.9836 and 0.9843, respectively). These correlations were much better than those reported by past researchers, in which lumped data for pigs at different growing stages were used. It may therefore be inferred that developing different linear equations for pigs at different ages should improve the accuracy in manure nutrient estimation using a hydrometer. Also, the error of using the hydrometer method to estimate manure TN and TP was found to increase, from +/- 10% to +/- 50%, with the decrease in TN (from 700 ppm to 100 ppm) and TP (from 130 ppm to 30 ppm) concentrations in the manure. The estimation errors for TN and TP may be larger than 50% if the total solids content is below 0.5%. In addition, the rapid settling of solids has long been considered characteristic of swine manure; however, in this study, the solids settling property appeared to be quite poor for nursery pig manure in that no conspicuous settling occurred after the manure was left statically for 5 hours. This information has not been reported elsewhere in the literature and may need further research to verify.

Animals↗
PubMed1975

Prediction of segmental parameters using the Hanavan human body model.

The Hanavan mathematical model of the human body was updated utilizing Clauser et al.'s multi-step weight distribution regression equations. The influence of these equations upon the predicted segment weights, specific gravities and principal moments of inertia of 30 adult male athletes was compared to that of Barter's regression equations employed in the original model. Both methods resulted in descrepancies between actual body weight and the predicted sum of the segment weights with Barter's equations consistently underestimating total body weight by an average of 2.03% and Clauser et al.'s overestimating it by 4.59%. Proportional distribution of the discrepancies produced corrected segment weights which were used in the Hanavan model. Clauser et al.'s equations predicted heavier trunks and thighs, and lighter heads, upper arms, forearms and hands with these differences being reflected in the specific gravities and principal moments of intertia. While it was not possible to establish the definite superiority of Clauser et al.'s equations in the prediction of body segment parameters, it is suggested from inferential evidence that they be used in subsequent biomechanical investigations of adult male athletes which involve the Hanavan model. It is also recommended that continued efforts be made to refine the Hanavan human body model.

Anthropometry↗
PubMed2006

Use of a urine color chart to monitor hydration status in nursing home residents.

To determine whether urine color, as measured by a color chart, might be a valid indicator of hydration status in frail nursing home residents, this study tested the associations between urine color and urine specific gravity. This is a descriptive correlational study set in seven nursing homes in eastern Iowa. Ninety-eight nursing home residents > or =65 years of age participated. Exclusion criteria for the study included: unstable congestive heart failure or diabetes, documented renal disease, hyponatremia (serum sodium <135 meq/L), terminal illness, acutely confused/delirious or urinary tract infection at baseline, and gastrostomy-tube dependence. Weekly urine specimens were collected. Ucol was measured first, using a urine color chart. Usg was determined using the Chemstrip Mini UA Urine Analyzer. Week-by-week Spearman rank order correlations between urine color and specific gravity for the total sample (n=98) ranged from r(s) = 0.3 - 0.7, p < .01; the PROC mixed model was significant, p < .01. In subgroup analyses (n=78), all females (r(s) = 0.67, p = .01) and both males (r(s) = 0.53, p = .01) and females (r(s) = 0.72, p =.01) with adequate renal function (Cockcroft-Gault estimated creatinine clearance [CrCl] values of > or =50 ml/min) had significant associations between average urine color and average Usg. Females with mild renal impairment (CrCl between 30 and 50 ml/min) also had significant associations between Ucol and Usg (r(s) = .64, p < .01). Ucol averaged over several individual readings offers another tool in assessing hydration status in Caucasian nursing home residents with adequate renal function measures by estimated CrCl values.

Aged↗
PubMed1979

Simple method for the collection of pancreatic islets by the use of Ficoll-Conray gradient.

Simple method for the collection of large numbers of viable pancreatic islets from normal rats is described. This method involves collagenase digestion of the pancreas, followed by the use of Ficoll-Conray discontinuous gradient for the separation of isolated islets from unwanted acinal debris. Ficoll-Conray A solution was prepared by mixing undialyzed 12.5% Ficoll and 33.4% Conray in the ratio 2 : 1, to make a specific gravity of 1.095 and osmolarity of 396 mOsm/l. The solution B, C, and D, with specific gravities 1.084, 1.072, and 1.048, respectively were obtained by diluting A solution with distilled water. Using Ficoll-Conray gradient, about 200 viable islets which maintained excellently their morphology and function, were collected consistently from a young adult rat pancreas.

Animals↗
PubMed1992

Radiographic appearance of bullet tracks in the lung.

Penetrating missile or bullet wounds to the lung result in a number of abnormalities visible on chest radiographs. One finding that is unique to pulmonary parenchyma is the bullet track, which occurs along the course of a bullet as it traverses the lung. A bullet track may occur in the lung because of this organ's low specific gravity and high elasticity. In other tissues, such as liver and brain, that have higher specific gravities and lower elastic content, bullet tracks are rarely, if ever, noted because widespread destruction usually occurs. Bullet tracks may have a delayed appearance on chest radiographs, and thus may cause confusion in interpretation if a history of injury is not elicited. With the increase in violet confrontations in the United States, it is more and more likely that radiologists will be asked to interpret chest radiographs of patients who have had penetrating bullet injuries to the thorax. In this pictorial essay, we illustrate the appearance of bullet tracks in lung on chest radiographs.

Humans↗
PubMed1991

Influence of sodium aluminosilicate, hydroxy-sodalite, carnegieite, aluminum sulfate, and aluminum phosphate on performance of commercial Leghorns.

Experiments were conducted to determine if the high ion-exchange capacity of sodium aluminosilicate (ZA) marketed as ETHACAL Feed Component or its aluminum content or both are related to the beneficial effect of ZA on egg specific gravity (ESG). In Experiments 1 and 2, ZA was compared with hydroxy-sodalite (HS) and carnegieite, which have the same chemical formula as ZA but little or no ion-exchange capacity. Two levels of ZA (0 and 1.5% of the diet) and three levels of HS (0, .75, and 1.5%) were fed in Experiment 1. In Experiment 2, 0, .75, and 1.5% of ZA and carnegieite were fed. In Experiment 3, ZA, carnegieite, aluminum sulfate, and aluminum phosphate were fed at levels calculated to contain .148 and .101% aluminum. Criteria evaluated were ESG, egg production, feed consumption, and egg weight. Egg specific gravity was significantly improved by ZA in all experiments and was not affected by HS, carnegieite (Experiments 1 and 2), aluminum sulfate (.148% Al), or aluminum phosphate (Experiment 3). Carnegieite and aluminum (.101%) from aluminum sulfate increased ESG in Experiment 3. In Experiments 1 and 3, egg production and feed consumption were not influenced by various treatments. Carnegieite and ZA reduced egg production and feed consumption in Experiment 2. It was concluded that the ion-exchange capacity and aluminum content of ZA may contribute to its beneficial effect on ESG.

Alum Compounds↗
PubMed1985

Effects of enterocentesis on peritoneal fluid constituents in the horse.

Peritoneal fluid was collected from 15 clinically normal horses and was analyzed for nucleated cell (NC) counts and specific gravity. Six horses (controls, group 1) were subjected to abdominocentesis only, with a teat cannula, every 24 hours for 5 days. There were no marked changes in the peritoneal fluid of these horses over the 5-day period. Peritoneal fluid was collected from 6 other horses (group 2) with an 8.89-cm 18-gauge needle. The needle was then advanced until intestinal fluid was obtained. Peritoneal fluid was then collected with teat cannulas at 24-hour intervals for an additional 4 days. Peritoneal fluid NC counts from group 2 horses were significantly increased (P less than 0.05) at peak values 2 days after enterocentesis. Specific gravities of peritoneal fluid from group 2 horses were increased on days 1 and 2 after enterocentesis (P greater than 0.05). Peritoneal fluid from 3 other horses (group 3) was collected before enterocentesis (base line) and again at 4-hour intervals after enterocentesis. Peritoneal fluid NC counts of group 3 horses were markedly increased above base-line values 4 hours after enterocentesis and continued to increase for up to 12 hours after enterocentesis when the experiment was terminated. All horses that underwent enterocentesis remained clinically normal except 1 group 3 horse that had a fever (39.6 C) 24 hours after enterocentesis.

Animals↗
PubMed1990

Brain water content, brain blood volume, blood chemistry, and pathology in a model of cerebral edema.

STUDY OBJECTIVES: The objective was to correlate regional changes during brain water content with alterations in blood chemistry and cerebral pathology during hypo-osmotic edema. PARTICIPANTS: Sprague-Dawley male adult rats were used in these studies. DESIGN: Animals were block-randomized to receive either an intraperitoneal distilled water injection equivalent to 5% or 15% of their body weight or no injection (controls). Rats were sacrificed 15 or 60 minutes after water injection or at an equivalent time for controls. INTERVENTIONS: No interventions were performed. MEASUREMENTS AND MAIN RESULTS: Water content of cerebral cortical gray and white matter was calculated from measurements of tissue specific gravity. Blood plasma osmolality and sodium and potassium concentrations were determined at various times after water injection. An index of blood-brain barrier permeability was obtained by measuring brain red blood cell and plasma volumes. A qualitative assessment of edema was made from light and electron micrographs of the cerebral cortex. We found that water injection produced a dose-dependent decrease in plasma osmolality and sodium concentration within 15 minutes. Cortical water content was unchanged after this period. An influx of water into cerebral gray, and, less readily, into cerebral white matter occurred during the next 15 minutes. Whole blood specific gravity and brain blood content were unchanged and thus did not confound the measurement of cerebral water content. Hematocrit was increased 60 minutes after a 15% water injection. The blood-brain barrier remained intact throughout this period. Microscopy revealed astrocytic swelling with slight extracellular fluid accumulation 60 minutes after the water injection. CONCLUSIONS: Homeostatic mechanisms in the cerebral cortex can maintain constant water content for at least 15 minutes during maintained intravascular hypo-osmolality. Fluid that subsequently moves into the tissue primarily enters an intracellular compartment. This model will be useful in investigating physiological mechanisms of brain water regulation and the pathogenesis of brain edema, a common clinical entity in emergency conditions.

Animals↗
PubMed1990

Experimental intracerebral hemorrhage: early removal of a spontaneous mass lesion improves late outcome.

The purpose of the present study was to determine whether early removal of an experimental intracerebral mass altered cerebral blood flow, brain water content, neuropathological findings, or neurological function 24 hours later. In three experimental series, a 50-microliter balloon was inflated within the right caudate nucleus in rats. At 24 hours after inflation, we studied cerebral blood flow by quantitative autoradiography, brain specific gravity, and qualitative histopathology by light microscopy. The animals were also assessed using a simple neurological deficit scale. In each series, half of the animals had the balloon inflated for 10 minutes (Group 1), and half had the balloon inflated permanently (Group 2). After transient inflation, there were surprisingly small differences in the blood flow between the two cerebral hemispheres at 24 hours. By contrast, in animals with permanent inflation, several indices of blood flow were significantly worse in the hemisphere ipsilateral to the balloon: the mean and median blood flow levels in the caudate nucleus; the mean blood flow in the cerebral cortex; and the area of cortex with ischemic levels of blood flow. The specific gravity was reduced in areas surrounding the site of balloon insertion after either transient or permanent inflation, and there was evidence of ischemic cell damage in all animals studied. These changes were more severe after permanent inflation, but the differences were not significant. Neurological outcome was significantly better after transient as compared with permanent inflation. The present findings contradict previous results and suggest that early removal of an intracerebral mass may have subsequent benefits.

Animals↗
PubMed1987

The effect of hypoxia on traumatic head injury in rats: alterations in neurologic function, brain edema, and cerebral blood flow.

We evaluated the effects of early posttraumatic hypoxia on neurologic function, magnetic resonance images (MRI), brain tissue specific gravities, and cerebral blood flow (CBF) in head-injured rats. By itself, an hypoxic insult (PaO2 40 mm Hg for 30 min) had little effect on any measure of cerebral function. After temporal fluid-percussion impact injury, however, hypoxia significantly increased morbidity. Of rats subjected to impact (4.9 +/- 0.3 atm) plus hypoxia, 71% had motor weakness contralateral to the impact side 24 h after injury, while only 29% of rats subjected to impact alone had demonstrable weakness (p less than 0.05). Lesions observed on MR images 24 h after injury were restricted to the impact site in rats with impact injury alone, but extensive areas with longer T1 relaxation times were observed throughout the ipsilateral cortex in rats with impact injury and hypoxic insult. Brain tissue specific gravity measurements indicated that much more widespread and severe edema developed in rats with impact injury and hypoxia. [14C]Iodoantipyrine autoradiography performed 24 h after injury showed that there was extensive hypoperfusion of the entire ipsilateral cortex in rats with impact injury and hypoxia. These results show that large areas of impact-injured brain are extremely vulnerable to secondary insults that can irreparably damage neural tissue, and provide experimental evidence for the observed adverse effects of hypoxia on outcome after human head injury.

Animals↗
PubMedDate not supplied

Papain: a novel urine adulterant.

The estimated number of employees in the United Stated screened annually for illicit drugs is approximately 20 million, with marijuana being the most frequently abused drug. Urine adulterants provide an opportunity for illicit drug users to obtain a false-negative result on commonly used primary drug screening methods such as the enzyme multiplied immunoassay technique and the fluorescence polarized immunoassay technique (FPIA). Typical chemical adulterants such as nitrites are easily detected or render the urine specimen invalid as defined in the proposed SAMHSA guidelines for specimen validity testing based on creatinine, specific gravity, and pH. Papain is a cysteine protease with intrinsic ester hydrolysis capability. The primary metabolite of the psychoactive chemical in marijuana, 11-norcarboxy-Delta9-tetrahydrocannibinol (THC-COOH), was assayed by FPIA in concentrations ranging from 25 to 500 ng/mL, at pH values ranging from 4.5 to 8, over the course of 3 days with papain concentrations ranging from 0 to 10 mg/mL. FPIA analysis of other frequently abused drugs: amphetamines, barbiturates, benzodiazepines, cocaine, opiates, and phencyclidine, along with gas chromatography-mass spectrometry (GC-MS) of THC-COOH and high-pressure liquid chromatography-ultraviolet detection (HPLC-UV) of nordiazepam was performed in order to determine if the mechanism of urine adulteration by papain was analyte specific. Control and adulterated urine specimens (n = 30) were assayed for creatinine, specific gravity, and pH to determine if papain rendered the specimens invalid based on the proposed SAMHSA guidelines. There was a direct pH, temperature, and time-dependent correlate between the increase in papain concentration and the decrease in THC-COOH concentration from the untreated control groups (p < 0.01). The average 72-h THC-COOH concentration decrease at pH 6.2 with a papain concentration of 10 mg/mL was 50%. Papain did not significantly decrease the concentration of the other drugs analyzed with the exception of nordiazepam. GC-MS of THC-COOH and HPLC-UV of nordiazepam revealed a 66% and 24% decrease in concentration of the respective analyte with 10 mg/mL papain after 24 h at room temperature (approximately 23 degrees C). No adulterated specimens were rendered invalid based on the SAMHSA guidelines. Immediate FPIA analysis is suggested to minimize the interfering effects of papain with regards to primary drug screening.

Chromatography, High Pressure Liquid↗
PubMed1973

A tumor antigen in tissue cultures derived from patients with Hodgkin's disease.

Pellets obtained from supernatant fluids of monolayer cultures of cells from patients with Hodgkin's disease were fractionated by isopycnic density sedimentation. Material in a peak of specific gravity 1.15-1.21 g/ml from two Hodgkin's disease cultures was used to immunize rabbits, and the antisera obtained in this manner were reacted by agar-gel diffusion and immunoelectrophoresis with antigens from the purified peaks and the unfractionated pellets of centrifuged culture medium from all the cultures. The antisera reacted with material from 9 of 10 lines derived from spleens of patients with Hodgkin's disease, 2 of 8 cell lines from histologically negative spleens from patients with Hodgkin's disease and with 3 of 6 lymphoma cell lines not diagnosed as Hodgkin's disease. The antisera did not react with 12 cell cultures prepared from normal adult and fetal spleen and thymus. The antigen from cultures from patients with Hodgkin's disease was not found in material sedimenting at lower specific gravities; it resisted Tweenether solubilization, and migrated as a single band by immunoelectrophoresis. The antigen was not found in disrupted, noncultured tumor cells from patients with Hodgkin's disease, and an antiserum against noncultured, minced tumor tissue did not react with the Hodgkin's disease tissue-culture material. No immunological relationship was found between the tissue culture antigen and Epstein-Barr, RD-114, or Rauscher murine leukemia viruses. The Hodgkin's disease antigen may be a tumorrelated antigen or a component of an oncogenic virus.

Animals↗
PubMed1993

Blood-brain barrier permeability, cerebral edema, and neurologic function after closed head injury in rats.

We previously described the time course of changes in neurologic status (as indicated by neurologic severity score [NSS]) and cerebral edema (as indicated by brain tissue specific gravity and water content) after closed head trauma in rats. The present study was designed to determine whether head trauma alters the integrity of the blood-brain barrier (BBB), the role of the BBB in edema formation and neurologic outcome, and the effect of MK-801 (a noncompetitive N-methyl-D-aspartate receptor antagonist) on BBB permeability. Rats in which cranial impact was delivered during ether anesthesia (n = 106) were killed at 15 min, 1, 2, 4, 10, and 24 h, and 2, 4, and 7 days. Control rats (n = 12) received no cranial impact. Subsets of head-injured rats killed at 4 and 24 h received MK-801 (3 mg/kg intraperitoneally) 1 h after injury. BBB permeability was assessed with intravenous injection of Evans Blue dye, cerebral edema was assessed by determining brain tissue specific gravity and water content, and neurologic status was assessed using NSS. Tissue extravasation of Evans Blue was maximal in the injured hemisphere 4 h after injury, but a residual BBB permeability defect was still evident as long as 4 days after the insult. In MK-801-treated rats, extravasation of Evans Blue in the injured hemisphere was not significantly different from that in the noninjured hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗