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At least 343 records · Page 19Linked to original sources
PubMed1999

Influence of early posttraumatic hypothermia therapy on local cerebral blood flow and glucose metabolism after fluid-percussion brain injury.

OBJECT: Using autoradiographic image averaging, the authors recently described prominent foci of marked glucose metabolism-greater-than-blood-flow uncoupling in the acutely traumatized rat brain. Because hypothermia is known to ameliorate injury in this and other injury models, the authors designed the present study to assess the effects of posttraumatic therapeutic hypothermia on the local cerebral metabolic rate of glucose (LCMRglu) and local cerebral blood flow (LCBF) following moderate parasagittal fluid-percussion head injury (FPI) in rats. METHODS: Either cranial hypothermia (30 degrees C) or normothermia (37 degrees C) was induced for 3 hours in matched groups of rats immediately after FPI; LCMRglu and LCBF were assessed 3 hours after concluding these temperature manipulations. In rats subjected to FPI, regardless of whether normothermia or hypothermia ensued, LCBF was reduced relative to the sham-injury groups. In addition, when FPI was followed by hypothermia (FPI-30 degrees C group), the subsequent LCBF was significantly lower (35-38% on average) than in FPI-37 degrees C rats. Statistical mapping of LCBF difference imaging data revealed confluent cortical and subcortical zones of significantly reduced LCBF (largely ipsilateral to the prior injury) in FPI-30 degrees C rats relative to the FPI-37 degrees C group. Local glucose utilization was reduced in both hemispheres of FPI-37 degrees C rats relative to the sham-injury group and was lower in the right (traumatized) hemisphere than in the left. However, LCMRglu values were largely unaffected by temperature manipulation in either the FPI or sham-injury groups. The LCMRglu/LCBF ratio was nearly doubled in FPI-30 degrees C rats relative to the FPI-37 degrees C group, in a diffuse and bihemispheric fashion. Linear regression analysis comparing LCMRglu and LCBF revealed that the FPI-37 degrees C and FPI-30 degrees C data sets were completely nonoverlapping, whereas the two sham-injury data sets were intermixed. CONCLUSIONS: Despite its proven neuroprotective efficacy, early posttraumatic hypothermia (30 degrees C for 3 hours) nonetheless induces a moderate decline in cerebral perfusion without the (anticipated) improvement in cerebral glucose utilization, so that a state of mild metabolism-greater-than-blood-flow dissociation is perpetuated.

Animals↗
PubMed1999

Exacerbation of cortical and hippocampal CA1 damage due to posttraumatic hypoxia following moderate fluid-percussion brain injury in rats.

OBJECT: Patients with head injuries often experience respiratory distress that results in a secondary hypoxic insult. The present experiment was designed to assess the histopathological consequences of a secondary hypoxic insult by using an established rodent model of traumatic brain injury (TBI). METHODS: Intubated anesthetized rats were subjected to moderate (1.94-2.18 atm) parasagittal fluid-percussion injury (FPI) to the brain. Following the TBI, the animals were maintained for 30 minutes by using either hypoxic (TBI-HY group, nine animals) or normoxic (TBI-NO, 10 animals) gas levels. Sham-operated animals also underwent all manipulations except for the FPI (sham-HY group, seven animals; and sham-NO group, seven animals). Three days after TBI the rats were killed, and quantitative histopathological evaluation was undertaken. Cortical contusion volumes were dramatically increased in the TBI-HY group compared with the TBI-NO group (p < 0.03). Qualitative assessment of cortical and subcortical structures demonstrated significant damage within the hippocampal areas, CA1 and CA2, of TBI-HY animals compared with the TBI-NO animals (both p < 0.03). There was also a significant increase in the frequency of damaged neuronal profiles within the middle and medial sectors of the CA1 hippocampus (p < 0.03) due to the hypoxic insult. CONCLUSIONS: The results of this study demonstrate that a secondary hypoxic insult following parasagittal FPI exacerbates contusion and neuronal pathological conditions. These findings emphasize the need to control for secondary hypoxic insults after experimental and human head injury.

Animals↗
PubMed2002

Cerebral metabolism after fluid-percussion injury and hypoxia in a feline model.

OBJECT: Currently, there are no good clinical tools to identify the onset of secondary brain injury and/or hypoxia after traumatic brain injury (TBI). The aim of this study was to evaluate simultaneously early changes of cerebral metabolism, acid-base homeostasis, and oxygenation, as well as their interrelationship after TBI and arterial hypoxia. METHODS: Cerebral biochemistry and O2 supply were measured simultaneously in a feline model of fluid-percussion injury (FPI) and secondary hypoxic injury. After FPI, brain tissue PO2 decreased from 33 +/- 5 mm Hg to 10 +/- 4 mm Hg and brain tissue PCO2 increased from 55 +/- 2 mm Hg to 81 +/- 9 mm Hg, whereas cerebral pH fell from 7.1 +/- 0.06 to 6.84 +/- 0.14 (p < 0.05 for all three measures). After 40 minutes of hypoxia, brain tissue PO2 and pH decreased further to 0 mm Hg and 6.48 +/- 0.28, respectively (p < 0.05), whereas brain tissue PCO2 remained high at 83 +/- 13 mm Hg. Secondary hypoxic injury caused a drastic increase in cerebral lactate from 513 +/- 69 microM/L to 3219 +/- 490 microM/L (p < 0.05). The lactate/glucose ratio increased from 0.7 +/- 0.1 to 9.1 +/- 2 after hypoxia was introduced. The O2 consumption decreased significantly from 18.5 +/- 1.1 microl/mg/hr to 13.2 +/- 2.1 microl/mg/hr after hypoxia was induced. CONCLUSIONS: Cerebral metabolism, O2 supply, and acid-base balance were severely compromised ultra-early after TBI, and they declined further if arterial hypoxia was present. The complexity of pathophysiological changes and their interactions after TBI might explain why specific therapeutic attempts that are aimed at the normalization of only one component have failed to improve outcome in severely head injured patients.

Acid-Base Equilibrium↗
PubMed2004

Effects of aminoguanidine and L-arginine methyl ester resuscitation following induction of fluid-percussion injury and severe controlled hemorrhagic shock in the rat brain.

OBJECT: In this study the authors compared the effects of both a selective inducible nitric oxide synthase (iNOS) inhibitor and a nonselective inhibitor on posttraumatic recovery and neuron survival by using a combined model of lateral fluid-percussion injury (FPI) and hemorrhagic shock (HS). METHODS: Male Sprague-Dawley rats weighing 300 to 350 g underwent FPI to the brain (3.5 atm) and hemorrhage to a mean arterial blood pressure (MABP) of 40 mm Hg for 1 hour. Rats were then resuscitated during 1 hour with bolus infusions of aminoguanidine (AG) or nitro-L-arginine methyl ester (L-NAME). Neuronal apoptosis was determined by performing Nissl staining and in situ terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique. Rats infused with AG showed a significant increase in mean survival time and cerebral tissue perfusion, although the MABP and nitrate/nitrite levels did not significantly change compared with those in L-NAME-treated rats even though both animal groups had been subjected to combined FPI and HS, FPI alone, or HS alone. Furthermore, infusion of AG also significantly decreased the number of apoptotic neurons when compared with the number in rats treated with L-NAME. CONCLUSIONS: The authors asserted that treatment with AG, which causes the inhibition of iNOS, might contribute to improved physiological parameters and neuronal cell survival following FPI and HS.

Animals↗
PubMed2005

Assessment of cerebral S100B levels by proton magnetic resonance spectroscopy after lateral fluid-percussion injury in the rat.

OBJECT: After traumatic brain injury (TBI), S100B protein is released by astrocytes. Furthermore, cerebrospinal fluid (CSF) and serum S100B levels have been correlated to outcome. Given that no data exist about the temporal profile of cerebral S100B levels following TBI and their correlation to serum levels, the authors examined whether proton magnetic resonance (MR) spectroscopy is capable of measuring S100B. METHODS: Results of in vitro proton MR spectroscopy experiments (2.35-tesla magnet, 25 G/cm, point-resolved spatially localized spectroscopy) revealed an Sl00B-specific peak at 4.5 ppm and confirmed a positive correlation between different S100B concentrations (10 nM-1 microM) and the area under the curve (AUC) for the S100B peak (r = 0.991, p < 0.001). Thereafter, proton MR spectroscopy was performed in male Sprague-Dawley rats (7 X 5 X 5-mm voxel in each hemisphere, TR 3000 msec, TE 30 msec, 256 acquisitions). Exogenously increased CSF S100B levels (approximately 200 ng/ml) through the intraventricular infusion of S100B increased the AUC of the S100B peak from 0.06 +/- 0.02 to 0.44 +/- 0.06 (p < 0.05), whereas serum S100B levels remained normal. Two hours after lateral fluid-percussion injury, serum S100B levels increased to 0.61 +/- 0.09 ng/ml (p < 0.01) and rapidly returned to normal levels, whereas the AUC of the S100B peak increased to 0.19 +/- 0.04 at 2 hours postinjury and 0.41 +/- 0.07 (p < 0.05) on Day 5 postinjury. CONCLUSIONS: Proton MR spectroscopy proves a strong correlation between the AUC of the S100B peak and S100B concentrations. Following experimental TBI, serum S100B levels increased for only a very short period, whereas cerebral S100B levels were increased up to Day 5 postinjury. Given that experimental data indicate that S100B is actively released following TBI, proton MR spectroscopy may represent a new tool to identify increased cerebral S100B levels in patients after injury, thus allowing its biological function to be better understood.

Animals↗
PubMed2002

A comparison of intrapulmonary percussive ventilation and conventional chest physiotherapy for the treatment of atelectasis in the pediatric patient.

OBJECTIVE: Compare intrapulmonary percussive ventilation (IPV) to conventional chest physiotherapy (CPT) and determine their effects on improving atelectasis and static compliance in pediatric patients. METHODS: We conducted a retrospective study of 46 patients who received IPV therapy with the Percussionator IPV-1 ventilator at frequencies of 180-220 cycles/min and pressures of 15-30 cm H(2)O. Medicated aerosol therapy with albuterol 2.5 mg in 6 mL normal saline solution was delivered with each IPV treatment. Baseline and subsequent chest radiographs were evaluated by a pediatric radiologist. We used an ordinal scoring system to measure the degree of atelectasis to evaluate chest radiographs (4 = complete collapse, 0 = complete resolution). Then we conducted a prospective, randomized, controlled study of intubated and mechanically ventilated patients to compare changes in atelectasis and static compliance. Baseline and daily chest radiographs were evaluated using the same scoring system as in the retrospective pilot evaluation. Patients were ventilated in the volume-controlled, synchronized intermittent mandatory ventilation mode, with tidal volumes of 6-10 mL/kg. Patients were randomized to CPT (clapping and vibration) or IPV at frequencies of 180-220 cycles/min and pressures of 15-30 cm H(2)O (equal to the peak pressures on the ventilator), with 6 mL of normal saline solution via medicated aerosol. Both treatments were given every 4 h and lasted 10-15 min. Static compliance measurements were calculated from exhaled tidal volumes and plateau pressures. RESULTS: In the retrospective study the median age of patients receiving IPV was 4.2 years and the median duration of IPV was 6.2 days. A change in atelectasis score from 3 to 1 (p < 0.001) was seen. In the randomized, controlled trial the median age of patients was 3.1 years. Atelectasis scores before treatment were comparable between the CPT and IPV groups (median 2.0 for both groups, p = 0.530). Atelectasis scores after treatment were unchanged in the CPT group (median 2.0, p = 0.421) but improved in the IPV group (median 1.0, p = 0.026). Treatment lasted an average of 6.2 days in the CPT group and 2.1 days in the IPV group (p = 0.018). Neither group showed any change in static compliance following treatment. CONCLUSIONS: In the retrospective study a clinically important improvement in atelectasis was seen in patients who received IPV therapy. In the controlled, clinical trial the IPV group showed more clinically important improvement in atelectasis than the CPT group. IPV is a safe and effective method of alternative airway clearance and can be used on patients with artificial airways.

Adolescent↗
PubMed1998

Effects of Exercise Following Lateral Fluid Percussion Brain Injury in Rats.

Previous studies have suggested that brain-derived neurotrophic factor (BDNF) is involved in memory and learning, and may be neuroprotective following various brain insults. Exercise has been found to increase BDNF mRNA levels in various brain regions, including specific subpopulations of hippocampal neurons. In the present study, we were interested in whether following traumatic brain injury, exercise could increase BDNF mRNA expression, attenuate neuropathology, and improve cognitive and neuromoter performance. We subjected adult male Sprague-Dawley rats to a fluid percussion brain injury, followed by either 18 days of treadmill exercise or handling. Spatial memory was evaluated in a Morris Water Maze (MWM) and motor function was evaluated with a battery of neuromotor tests. Neuropathology was evaluated by measuring the cortical lesion volume and the extent of neuronal loss in the hipocampus. Expression of BDNF mRNA in the hippocampus was assessed with in situ hybridization and densitometry. Hybridization signal for BDNF mRNA was significantly increased bilaterally in the exercise group in hippocampal regions CA1 and CA3 (p<0.05), but not in the granule cell layer of the dentate gyrus. No significant differences were observed between the groups in neuropathology, spatial memory, or motor performance. This study suggests that after traumatic brain injury, exercise elevates BDNF mRNA in specific regions of the hippocampus.

Journal Article↗
PubMed2003

Effect of intrapulmonary percussive ventilation on mucus clearance in duchenne muscular dystrophy patients: a preliminary report.

OBJECTIVE: To determine the effects of intrapulmonary percussive ventilation (IPV) on mucus clearance in tracheostomized Duchenne muscular dystrophy patients. METHODS: We studied 8 patients, 5 of whom had mucus hypersecretion (> 30 mL/d). In a randomized, cross-over study we compared assisted mucus clearance techniques with and without IPV. There were 2 treatment sequences and each patient received 5 consecutive days of each treatment sequence, delivered 3 times a day. One sequence consisted of (1) assisted mucus clearance technique (AMCT, which involves forced expiratory technique and manual assisted cough), (2) endotracheal suctioning, (3) nebulizer administration of 5 mL of 0.9% sodium chloride solution for 5 min, (4) a second AMCT session, (5) endotracheal suctioning, (6) 45 min after the end of the nebulizer treatment a third AMCT session, (7) endotracheal suctioning. The other treatment sequence was the same except that it included IPV during the 5-min nebulizer treatment. The collected secretions were weighed. Vital capacity was measured once, before the treatments. Heart rate, respiratory rate, oxyhemoglobin saturation, end-tidal carbon dioxide, airway resistance, and peak expiratory flow were measured before and at 45 min after the treatments. Mean values were compared using analysis of variance with repeated measures. RESULTS: In patients with hypersecretion the mean +/- SD weight of the collected secretions was significantly higher with IPV (6.53 +/- 4.77 g vs 4.57 +/- 3.50 g, p = 0.01). Heart rate, respiratory rate, oxyhemoglobin saturation, end-tidal carbon dioxide, airway resistance, and peak expiratory flow did not differ statistically between the 2 treatments. CONCLUSIONS: IPV is a safe airway clearance method for tracheostomized Duchenne muscular dystrophy patients, and this preliminary study suggests that IPV increases the effectiveness of assisted mucus clearance techniques.

Administration, Inhalation↗
PubMed2003

High frequency percussive ventilation (HFPV). Principles and technique.

In recent years, the usefulness of high frequency ventilation (HFV) has been clinically reassessed as an alternative to conventional mechanical ventilation (CMV). HFV has often been combined with or in some cases even completely replaced CMV in the attempt to reduce iatrogenic injury. High frequency percussive ventilation (HFPV) is a specific mode of HFV that has been successfully applied in the treatment of acute respiratory failure after smoke inhalation; it has also been more widely used in pediatric than in adult patients. This article gives an introduction to and a description of the basic principles of HFPV, a mode of ventilation which we found particularly versatile and reliable in our preliminary clinical experience with the maneuver.

Equipment Design↗
PubMed2003

High frequency percussive ventilation (HFPV). Case reports.

Treatment of acute respiratory failure is still a hot issue in intensive care everyday practice: in the last few years high frequency ventilation techniques have been employed as a therapy for adult respiratory distress syndrome (ARDS) and acute respiratory failure (ARF). We applied high frequency percussive ventilation (HFPV) to 3 patients affected by ARDS or ARF, who did not improve after 24 hours of conventional mechanical ventilation (CMV). All our patient underwent 12 hours of HFPV, and showed an improvement of both respiratory exchange and radiological imaging. Even if the pathogenesis of ARF was quite different, in all patient we registered a good response and no complications.

Aged↗
PubMed2004

[The expression of bFGF and its receptor FGFR1 in rat after fluid-percussive brain injury].

OBJECTIVE: Study on the pattern of changes of bFGF and FGFR1 immunoreactivity occurred in the experimental brain injury model for the purpose of providing the scientific basis for molecular pathological diagnosis, forensic identification, clinical treatment as well as further ascertaining the molecular mechanism of brain injury. METHODS: Male SD rats were divided into normal control, sham operation control and injury groups. The rats of injury groups were subjected to moderate lateral fluid percussion brain injury (0.2 mPa). The injury groups were then subdivided into 30 min, 1, 3, 6, 12 h, 1, 3, 7 d groups according to the time elapsed after injury. The SP immunohistochemistry method was used to examine the expression of both bFGF and FGFR1 factors in rat brain. RESULTS: In the brain of normal control and sham operation control groups, the low expression levels of bFGF and FGFR1 were observed. The increase of bFGF and FGFR1 immunoreactivity could be observed 6 h after injury in cortex and brain stem, reached to the peak at 1 d and remained at the high level up to 3 d, then partly declined at 7 d. In hippocampus, however, the increase occur as early as 3 h after injury, reached to the peak at 1 d and then decreased progressively, and returned to basal level at 7 d. CONCLUSION: The results suggested that brain injury induced the gene expressions of bFGF and FGFR1. The bFGF may contribute to maintenance of nerve cell survival and the repair of damaged neural tissues after CNS injury and the patterns of their level change were quite regular and can be used for timing of injury in forensic medicine aspect.

Animals↗
PubMed2004

[A study of the expression of Fas after fluid percussion brain injury in rats].

OBJECTIVE: To study the pathologic diagnosis and the injury time estimation in light closed encephalon injury. METHODS: Mice were hurt by fluid percussion, and were killed at 15, 30 min, 1, 3 , 6, 12 h, 1, 4, 7, 14 d respectively after injury. The expression of Fas-L in the cerebral cortex, thalamus, and hippocampi was detected by immunohistochemistry and the results were assessed by image analysis system. RESULTS: It is showed that the expression of Fas-L could be detected in 1 h after injury, and increased significantly in three hours, and it reached apex 12 h after injury, and decreased gradually four days after injury, and returned normal 14 days after injury. CONCLUSION: This research demonstrated that Fas-L mediated apoptosis appeared not only around brain trauma but also in the brain tissue far away from the traumatic area. It indicted that the expression of Fas-L is a useful target for diagnosis of early brain injury; the regularity of Fas-L expression could be used as one of indication to date the time of brain injury.

Animals↗
PubMed2005

[The expression of Fas after fluid percussion brain injury in rats].

OBJECTIVE: To inquire into the pathologic diagnosis and the dating of injuries of light closed encephalon injury. METHODS: Wistar rats were hurt by fluid percussion, and were killed respectively at 15 min, 30 min, 1 h, 3 h, 6 h, 12 h, 1 d, 4 d, 7 d, and 14 d after injury. The expression of Fas in the cerebral cortex, thalamus, and hippocampi was detected by immunohistochemistry and the results were assessed by image analysis system. RESULTS: The results showed that the expression of Fas could be detected in thirty minutes after injury, and then it increased significantly in three hours, reached apex in twelve hours after injury, decreased gradually in four days after injury, and returned to normal in 14 days after injury. CONCLUSION: This research demonstrated that Fas-mediated apoptosis appeared not only around brain trauma but also in the brain tissue far away from the traumatic area. It indicted that Fas expression is a useful target for diagnosis of early brain injury and the regularity of Fas expression could be used as one of indications in deducing the time of brain injury.

Animals↗
PubMed2005

[Effect of intrapulmonary percussive ventilation in a severely disabled patient with persistent pulmonary consolidation].

An intrapulmonary percussive ventilator (IPV) improves airway clearance and lung function, and is useful for wide variety of respiratory disorders, such as cystic fibrosis, chronic obstructive pulmonary disease, aspiration pneumonia, and neuromuscular diseases. However, there are few reports on IPV use in patients with severe neurological impairment, scoliosis and thoracic deformity. They have poor mobility of the rib cage and difficulty in sputum expectoration. The use of IPV significantly improved persistent consolidation shown by chest computed tomography (CT) in one of such patients. The patient was a 33-year-old woman with severe spastic quadriplegia and tracheostomy and she was dependent on mechanical ventilation because of chronic restrictive respiratory failure. After fever and mild hypoxemia for one day, chest CT revealed consolidation of the left lower lobe. An IPV-I ventilator was used for 15 min once a week, with a stroke frequency of 250-300 cycles/min and pressure of 22 PSI. Mechanical ventilation was withheld during the IPV therapy. Chest physiotherapy was also done. According to the worsening of the consolidation on chest CT, the frequency of IPV was changed to once a day at day 23 and then to twice a day. Chest CT at day 44 showed further improvement. In patients with severe motor and intellectual disabilities, it is sometimes difficult to control progressive deterioration of pulmonary function and persistent atelectasis even with tracheostomy, mechanical ventilation, and conventional physiotherapy. Our results indicate that IPV may improve respiratory functio and the quality of life in such patients.

Adult↗
PubMed2006

[Expression of caspase-8 after brain injury from fluid percussion in rats].

OBJECTIVE: To provide the evidence of the relationship between brain injury and the time of injury. METHODS: Rats were contused on brain by fluid percussion, then were killed after injury for 15 min, 30 min, 1,3,6,12 h, and 1,4,7,14 d respectively. The expression of caspase-8 were detected by immunohistochemical technology on rat brain section and the results were assessed by image analysis system in the cerebral cortex, thalamus, and hippocampus. RESULTS: The expression of caspase-8 in cortex and hippocampus could be detected in 30 min after injury, increased significantly in 3h, reached apex in 1d after injury, remained 4d before decreased. In addition, the expression of caspase-8 can be detected in 1h after injury and reached apex in 1d after injury, and remained 4d then reduced. CONCLUSION: It seems that the expression of caspase-8 should be a useful target for diagnosis of early brain injury.

Animals↗
PubMed1990

Comparison of neck dislocation and percussion of the head on visual evoked responses in the chicken's brain.

The effect of neck dislocation, by stretching or by crushing, on the ability of the chicken's brain to sustain visual evoked responses was compared with the effect of a percussive blow. Less than 10 per cent of the birds whose necks were dislocated showed signs of concussion. It was concluded that neck dislocation may not concuss chickens, and that it is therefore uncertain whether it induces instantaneous unconsciousness.

Animal Welfare↗
PubMed1990

Comparative studies of edema produced by fluid percussion injury with lateral and central modes of injury in cats.

Earlier studies by our laboratories indicated that severe fluid percussion injury in cats results in the development of significant brain edema. In this study we measured the spatial distribution of edema developed after both central and lateral modes of impact with the objective of determining the degree to which the edema volume may contribute to ICP elevation and neurologic deterioration. All animals developed a marked increase in tissue water, particularly in the brainstem. In laterally injured cats, the increase in brainstem water equaled the edema produced supratentorially. Adding the increase of brainstem edema and the edema volume of the supratentorial compartment, we found an average water increase of 1.125 cc in survivors and 2.492 cc in nonsurvivors. This represents a significant volume increase when it is considered that the average PVI of the normal cat is approximately 0.9 cc (6). However, we observed that the PVI was reduced soon after injury and at a time when it has been reported that water content was near normal levels (7). Taking these studies in concert, we believe that the early reduction in PVI is most probably due to vascular swelling. The developing edema further contributes to reductions in PVI, thus setting the stage for elevated ICP and the tissue impaction observed in nonsurvivors.

Animals↗
PubMed1987

[Intrapulmonary percussion--a secretolytic treatment method].

Intrapulmonary percussion means the utilization of high-frequency ventilation as therapeutic and secretolytic principle. It succeeded by modification of the BIRD Mark 8 to realize an effective secretolytic treatment. The value of this method will be explained by 3 cases.

Adult↗