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

Restoration of cerebrovascular responsiveness to hyperventilation by the oxygen radical scavenger n-acetylcysteine following experimental traumatic brain injury.

Previous experiments have shown that, following experimental fluid-percussion brain injury, cyclo-oxygenase-dependent formation of oxygen radicals prevents arteriolar vasoconstriction in response to hyperventilation. The oxygen radical scavengers superoxide dismutase and catalase restore normal reactivity; however, they are not routinely available for clinical use. The present study tested whether n-acetylcysteine (Mucomyst), an agent currently available for acetaminophen toxicity, could be used as a radical scavenger to restore reactivity after brain injury. N-acetylcysteine (163 mg/kg) was given intraperitoneally prior to or 30 minutes after fluid-percussion brain injury (2.6 atm) in cats, and reactivity to hyperventilation was tested 1 hour after injury. The authors found either that pre- or postinjury administration led to normal reactivity. Additional experiments supported the hypothesis that n-acetylcysteine is an oxygen radical scavenger, since it reduced or prevented the free radical-dependent cerebral arteriolar dilation normally induced by the topical application of arachidonic acid or bradykinin. The mechanism by which n-acetylcysteine is effective in trauma may involve direct scavenging of radicals or stimulation of glutathione peroxidase activity. The results suggest that n-acetylcysteine may be useful for treatment of oxygen free radical-mediated brain injury.

Acetylcysteine↗
PubMed1991

The effect of age on outcome following traumatic brain injury in rats.

Age of the patient is one of the most important predictors of outcome following human traumatic brain injury. This study employs the fluid-percussion model to investigate the effects of aging on outcome following traumatic brain injury in rats. The results revealed that there was an age-associated increase in mortality rate following both low (1.7 to 1.8 atm) and moderate (2.00 to 2.25 atm) levels of traumatic brain injury. Age-related changes in systemic physiological, neurological, and histopathological indexes of brain injury were also examined following a low level of traumatic brain injury. Traumatic brain injury produced equivalent acute hypertension and increased plasma glucose levels in both young adult and aging rats. Injury produced an acute increase in heart rate in the young adult rat group, while the heart rate decreased in the aged rats. At low levels of brain injury, no significant gross histopathological alterations were produced in either age group. Neurological outcome was assessed by measuring the duration of suppression of a number of nonpostural and postural reflexes and more complex somatomotor functions (righting, escape, head support). Except for head support, there was a significant age-related increase in the duration of the suppression of these reflexes following brain injury. These data demonstrate that aging is associated with an increased mortality rate and greater acute neurological deficits following traumatic brain injury. These data also demonstrate the usefulness of the fluid-percussion model for studying the mechanisms responsible for the age-related increase in vulnerability to brain injury.

Aging↗
PubMed1995

Effects of acute ethanol intoxication on experimental brain injury in the rat: neurobehavioral and phosphorus-31 nuclear magnetic resonance spectroscopy studies.

Using the lateral fluid-percussion model of experimental brain injury in the rat, the authors investigated the effect of acute ethanol (EtOH) intoxication on cardiovascular changes, neurological motor deficits, brain bioenergetics, and mortality associated with traumatic brain injury. Two hours after gastric administration of EtOH (low dose in 20 animals, 1.5 g/kg; high dose in 28, 3.0 g/kg) or saline (equal volume), animals were subjected to a fluid-percussion brain injury centered over the left parietal cortex. These injuries were of either moderate (X = 2.2 atm; 10 animals/treatment) or high severity (X = 3.0 atm; 18 animals/saline, 10 animals/low-dose EtOH, and 18 animals/high-dose EtOH). Neurological motor function was evaluated daily over a 1-week period, while a subset of eight animals receiving high-dose EtOH and subjected to brain injury of high severity were monitored for 4 hours using phosphorus-31 nuclear magnetic resonance spectroscopy to determine intracellular pH, free magnesium, and brain cytosolic phosphorylation potential. A significant (p < 0.05) and prolonged (up to 1 hour) hypotension was observed in animals pretreated with either low- or high-dose EtOH. Neither low-dose (blood-EtOH concentration = 110 +/- 40 mg/dl) nor high-dose (blood-EtOH = 340 +/- 70 mg/dl) EtOH had any effect on survival or neurological motor function after moderate brain injury. Following severe brain injury, animals pretreated with high-dose (blood-EtOH concentration = 352 +/- 65 mg/dl) EtOH showed a significantly increased mortality and markedly worsened neurological deficits at 24 hours postinjury. Following injury, free magnesium and cytosolic phosphorylation potential declined in both groups by approximately 50% to 60%, with no significant differences between groups with respect to these variables. In contrast, brain intracellular pH in the EtOH-treated animals was consistently higher than in the control group after injury. These data suggest that prior exposure to EtOH, particularly at high concentrations, may have detrimental effects on neurobehavioral function and survival in the acute period (up to 24 hours) after severe brain injury, and may be associated with posttraumatic cerebral alkalosis.

Alcoholic Intoxication↗
PubMed1998

Role of nitric oxide in traumatic brain injury in the rat.

OBJECT: Although nitric oxide (NO) has been shown to play an important role in the pathophysiological process of cerebral ischemia, its contribution to the pathogenesis of traumatic brain injury (TBI) remains to be clarified. The authors investigated alterations in constitutive nitric oxide synthase (NOS) activity after TBI and the histopathological response to pharmacological manipulations of NO. METHODS: Male Sprague-Dawley rats underwent moderate (1.7-2.2 atm) parasagittal fluid-percussion brain injury. Constitutive NOS activity significantly increased within the ipsilateral parietal cerebral cortex, which is the site of histopathological vulnerability, 5 minutes after TBI occurred (234.5+/-60.2% of contralateral value [mean+/-standard error of the mean ¿SEM¿], p < 0.05), returned to control values by 30 minutes (114.1+/-17.4%), and was reduced at 1 day after TBI (50.5+/-13.1%, p < 0.01). The reduction in constitutive NOS activity remained for up to 7 days after TBI (31.8+/-6.0% at 3 days, p < 0.05; 20.1+/-12.7% at 7 days, p < 0.01). Pretreatment with 3-bromo-7-nitroindazole (7-NI) (25 mg/kg), a relatively specific inhibitor of neuronal NOS, significantly decreased contusion volume (1.27+/-0.17 mm3 [mean+/-SEM], p < 0.05) compared with that of control (2.52+/-0.35 mm3). However, posttreatment with 7-NI or pre- or posttreatment with nitro-L-arginine-methyl ester (L-NAME) (15 mg/kg), a nonspecific inhibitor of NOS, did not affect the contusion volume compared with that of control animals (1.87+/-0.46 mm3, 2.13+/-0.43 mm3, and 2.18+/-0.53 mm3, respectively). Posttreatment with L-arginine (1.1+/-0.3 mm3, p < 0.05), but not 3-morpholino-sydnonimine (SIN-1) (2.48+/-0.37 mm3), significantly reduced the contusion volume compared with that of control animals. CONCLUSIONS: These data indicate that constitutive NOS activity is affected after moderate parasagittal fluid percussion brain injury in a time-dependent manner. Inhibition of activated neuronal NOS and/or enhanced endothelial NOS activation may represent a potential therapeutic strategy for the treatment of TBI.

Animals↗
PubMed1999

Survival and integration of transplanted postmitotic human neurons following experimental brain injury in immunocompetent rats.

OBJECT: Limitations regarding cell homogeneity and survivability do not affect neuronlike hNT cells, which are derived from a human teratocarcinoma cell line (Ntera2) that differentiates into postmitotic neurons with exposure to retinoic acid. Because NT2N neurons survive longer than 1 year after transplantation into nude mice brains, the authors grafted these cells into the brains of immunocompetent rats following lateral fluid-percussion brain injury to determine the long-term survivability of NT2N cell grafts in cortices damaged by traumatic brain injury (TBI) and the therapeutic effect of NT2N neurons on cognitive and motor deficits. METHODS: Seventy-two adult male Sprague-Dawley rats, each weighing between 340 and 370 g, were given an anesthetic agent and subjected to lateral fluid percussion brain injury of moderate severity (2.2-2.5 atm in 46 rats) or to surgery without TBI (shamoperation, 26 rats). Twenty-four hours postinjury, 10(5) NT2N cells (24 injured animals) or 3 microl of vehicle (22 injured and 14 control animals) was stereotactically implanted into the periinjured or control cerebral cortex. Motor function was assessed at weekly intervals and all animals were killed at 2 or 4 weeks after their posttraumatic learning ability was assessed using a Morris water maze paradigm. Viable NT2N grafts were routinely observed to extend human neural cell adhesion molecule-(MOC-1)immunoreactive processes into the periinjured cortex at 2 and 4 weeks posttransplantation, although no significant improvement in motor or cognitive function was noted. Inflammation identified around the transplant at both time points was assessed by immunohistochemical identification of macrophages (ED-1) and microglia (isolectin B4). CONCLUSIONS: Long-term survival and integration of NT2N cells in the periinjured cortex of immunocompetent rats provides the researcher with an important cellular system that can be used to study maturation, regulation, and neurite outgrowth of transplanted neurons following TBI.

Animals↗
PubMed2002

Stilbazulenyl nitrone, a novel azulenyl nitrone antioxidant: improved neurological deficit and reduced contusion size after traumatic brain injury in rats.

OBJECT: Stilbazulenyl nitrone (STAZN) is a second-generation azulenyl nitrone that has markedly enhanced antioxidant properties compared with those of conventional alpha-phenyl nitrones. In this study, the authors assessed the potential efficacy of STAZN in a rodent model of fluid-percussion brain injury, which results in a consistent cortical contusion. METHODS: After anesthesia had been induced in normothermic Sprague-Dawley rats (brain temperature 36-36.5 degrees C) by halothane-nitrous oxide, the animals were subjected to a right parietooccipital parasagittal fluid-percussion injury (1.5-2 atm). The agent (STAZN, 30 mg/kg: eight animals) or vehicle (dimethyl sulfoxide; eight animals) was administered intraperitoneally at 5 minutes and 4 hours after trauma. The neurological status of each rat was evaluated on Days 1, 2, and 7 postinjury (normal score 0, maximum injury 12). Seven days after trauma, the rat brains were perfusion fixed, coronal sections at various levels were digitized, and areas of contusion were measured. Treatment with STAZN significantly improved neurological scores on Days 2 and 7 postinjury compared with vehicle-treated rats. Administration of STAZN also significantly reduced the total contusion area by 63% (1.8 +/- 0.5 mm2 in STAZN-treated animals compared with 4.8 +/- 2.1 mm2 in vehicle-treated animals; p = 0.04) and the deep cortical contusion area by 60% (1.2 +/- 0.2 mm2 in STAZN-treated animals compared with 2.9 +/- 1.2 mm2 in vehicle-treated animals; p = 0.03). By contrast, hippocampal cell loss in the CA3 sector was unaffected by STAZN treatment. CONCLUSIONS: Therapy with STAZN, a novel potent antioxidant, administered following traumatic brain injury, markedly improves neurological and histological outcomes. Azulenyl nitrones appear to represent a promising class of neuroprotective agents for combating this devastating condition.

Animals↗
PubMed1987

Bone and joint pathology in workers using hand-held vibrating tools. An overview.

A literature evaluation was made with regard to the radiological documentation of bone and joint pathology in the hands and arms of workers using vibrating tools. There is evidence that work with pneumatic percussive tools (such as chipping hammers and scalers) may cause premature elbow and wrist osteoarthrosis, although of very low prevalence. This work-related disorder is not specific to vibration exposure. Instead, it is likely to result from the strong dynamic and static joint loading (often in extreme positions of the joint) and the repetitive hand-arm movements (sometimes also repeated minor traumatization) typical for tool manipulation in any heavy labor. Exposure to low-frequency percussion may, however, play a particular etiologic role: damage to the joint cartilage by repeated shocks from the tool, additional articular load (and consequent strain) associated with a vibration-induced increase in the need for joint stabilization and higher gripping forces, the tonic vibration reflex (which increases muscle contraction), and a stronger grip induced when tactile sensibility is diminished by vibration. So far, no investigations have ventured into the great complexity of possible confounders and effect modifiers. -A constitutional susceptibility may be required to produce osteoarthrosis. -The allegation that hand-arm vibration exposure causes an excess prevalence of bone cysts, vacuoles, Kienböck's disease, or pseudarthrosis of the scaphoid has not been validly documented. -Exposure to vibration of higher frequencies (such as from rotating drills, grinders, and chain saws) does not seem to be associated with excess bone and joint pathology. -The observed large variation in the prevalence of skeletal disorders may be explained by biodynamic and ergonomic differences between various occupations.

Arm↗
PubMed1986

Vibration from riveting tools in the frequency range 6 Hz-10 MHz and Raynaud's phenomenon.

The vibration characteristics of hand-held riveting hammers and bucking bars used in the aircraft industry were measured and recorded for frequencies from 6 Hz to 10 MHz. Three different measuring systems had to be used. Up to about 1 kHz a displacement transducer was used, up to about 50 kHz a piezoelectric accelerometer was used, and in the megahertz region an ultrasonic probe was used. The signals were analyzed according to the guidelines of the International Organization for Standardization (ISO/DIS 5349), and also according to methods common in environmental engineering. The weighted acceleration according to ISO/DIS 5349 was between 10 and 11 m/s2 for typical riveting tools. Very high acceleration values were obtained for frequencies above those specified in ISO/DIS 5349. In a group of 288 riveters, about 50% showed symptoms indicating Raynaud's phenomenon after about 10 years of work, although the daily exposure of riveting tools was about 1 min/d. The investigation showed that special precautions must be taken to measure the acceleration of percussion tools and that the risk criteria in ISO/DIS 5349 do not cover all the risks connected with percussion tools.

Aircraft↗
PubMed2006

Patients presenting to the general practitioner with pain of dental origin.

Dentofacial pain is a common presentation in general practice, and more than 50% of cases arise from dentally related pathology. In a carious tooth, pain that is site-specific, severe and spontaneous usually denotes extension of caries into the tooth pulp. Caries does not always appear as a cavity in the tooth, but may lie beneath intact enamel or on surfaces between teeth. Examination of tooth pain should include firm percussion (eg, with a tongue depressor). Tenderness on percussion denotes progression of infection into the subdental tissue. Pain occurring 24-48 hours after a tooth extraction is commonly caused by superficial osteitis in the exposed alveolar bone. Examination will reveal the absence of a blood clot in the extraction socket and severe tenderness on local palpation. Severe pain related to impacted wisdom teeth is frequently caused by pericoronitis, an infection in the gingival tissues surrounding the tooth. The surrounding gingiva is erythematous and tender to palpation. Localised facial swellings of dental origin require immediate referral to a dentist. Progressive facial swelling requires aggressive antibiotic therapy and referral to hospital for definitive management.

Adult↗
PubMed1998

Accuracy of clinical manoeuvres in detection of minimal ascites.

A study was conducted to assess the clinical accuracy of various clinical manoeuvres and signs used routinely for detection of ascites. Sixty-six patients admitted in medical ward of a teaching hospital after initial screening by a consultant were selected. Exclusion criteria were; cases with previous history of ascites, who had undergone paracentesis in the recent past or with evidence of ascites from history. Another clinician blind to history and clinical details assessed the presence of ascites by the selected methods a sonographer blind of clinical and historical details assessed the cases for presence of ascitic fluid. The clinical findings were compared using ultrasonographic (USG) findings as gold standard. Ascites was detected in 35 patients by USG. the mean weight and abdominal girth of study subjects with or without ascites were comparable (p > 0.05). Sensitivity of auscultatory percussion was highest (65.7%) followed by flank dullness (57.1%) and least for fluid wave sign (20.0%). Fluid wave sign had the highest specificity (100%). We found that none of the manoeuvres studied for detection of ascites was both highly sensitive and specific. However, auscultatory percussion could be useful for initial screening of patients to detect ascites.

Adult↗
PubMed2000

Bilateral growth-related protein expression suggests a transient increase in regenerative potential following brain trauma.

The potential of mature central nervous system (CNS) neurons to regenerate after injury represents a fundamental issue in neurobiology. The regional expression of proteins associated with axonal elongation, such as microtubule-associated protein 1B (MAP1B), its phosphorylated isoform (MAP1B-P), growth-associated protein 43 (GAP-43), and polysialylated neural cell-adhesion molecule (PSA-NCAM), was examined using immunohistochemistry from 24 hours to 2 months following lateral fluid percussion brain injury of moderate severity (2.4-2.6 atmospheres) in anesthetized rats. Uninjured (control) rats were subjected to anesthesia and surgery without injury or were subjected to anesthesia alone. Within the site of maximal injury, only increases in MAP1B and MAP1B-P were observed. Increased immunoreactivity was observed bilaterally for all growth-related proteins that were evaluated. By 24 hours postinjury, MAP1B and MAP1B-P increased within the cortex (P < 0.01) and the hippocampus (P < 0.001), whereas MAP1B-P also was elevated in the thalamus (P < 0.05). Within the dentate gyrus, increased immunoreactivity was observed for all proteins examined. By 48 hours postinjury, GAP-43 was elevated bilaterally within the inner molecular layers of the dentate gyrus (P < 0.005) and within the stratum lacunosum moleculare (P < 0.01), the stratum radiatum (P < 0. 005), and the stratum oriens (P < 0.05) of the hippocampus. Increased numbers of PSA-NCAM-labeled neurons were observed in the granule cell layers of the dentate gyrus from 48 hours through 2 weeks postinjury (P < 0.0005). The bilateral nature of increased expression of growth-related proteins differs from unilateral patterns of neuronal degeneration previously characterized for the lateral fluid-percussion model of brain injury. Taken together, these results suggest the existence of a temporary posttraumatic state in which the CNS may have increased regenerative potential. Enhancement of such a response may be one therapeutic strategy in treating CNS injury.

Animals↗
PubMed2002

[The clinical evaluation of tinidazole-iodoform-phenocamphor paste as an intra-canal sterilization medication for acute periapical periodontitis].

OBJECTIVE: To compare the clinical effect of tinidazole-iodoform-phenocamphor paste on acute periapical periodontitis with of formocresol. METHODS: 80 permanent teeth of acute periapical periodontitis were selected and divided randomly into tinidazole-iodoform-phenocamphor paste group (T group) and formocresol group (C group). The periapical signs and symptoms were recorded. Radiographs were taken and periapical radiolucent areas were calculated. After root canal preparation,the tinidazole-iodoform-phenocamphor paste was used as an intra-canal dressing medication for 7 days in T group and the formocresol paper point was used in C group. During the course of root canal treatment,the standard paper-point sampling method was used to collect and quantify the periapical exudates and the clinical findings were assessed with clinical periapical index(CPI). All statistical analyses were finished with Sigmastat software. RESULTS: At the first visit, there was no significant difference between two groups of CPI indexes and exudates volumes (P>0.05). The stepwise regression results suggested that exudates volumes had a significant correlation to periapical percussion(P=0.0031). There was a close relationship between radiolucent areas and periapical percussion or swelling degree (P=0.1148, P<0.0001). After the root canal sterilization, there was a statistically significant decrease in exudates volumes and CPI indexes (P<0.01), but the difference of exudates volumes and CPI indexes between two groups was not statistically significant (P>0.05). CONCLUSION: It indicated that tinidazole-iodoform-phenocamphor paste had the same effect on controlling acute periapical periodontitis as that of formocresol.

Clinical Trial↗
PubMed1992

[The reflex hammer].

When Erb began to study the knee jerk around 1870 he was able to use the percussion hammer for this purpose. Whereas percussion nowadays is performed with bare fingers, every physician carries a reflex hammer in his bag. Many varieties of reflex hammer have been developed. Their distribution today depends on their use by different schools. The origins and development of the most popular contemporary reflex hammers in English, French and German speaking countries are described.

Equipment Design↗
PubMed2006

Retrospective clinical and radiologic evaluation of nonsurgical endodontic treatment in human immunodeficiency virus (HIV) infection.

PURPOSE: This retrospective study evaluated the clinical and radiographic status of nonsurgical endodontic treatment (ET) of anterior and posterior teeth in HIV-seropositive patients. METHODS: ET was analyzed in 26 anterior and 34 posterior teeth from 54 consecutive HIV patients (gender ratio 3 Male : 1 Female, mean age 40.2 years, mean CD4 240, CD4<500 in 88%, 12 with AIDS) over a six year period with a minimum of six months follow-up. ET was evaluated as successful, questionable, or failure based upon clinical factors (palpation, mobility, sinus tract, percussion, function, infection/swelling, occlusion, symptoms) and radiographic factors (periodontal ligament space, rarefaction, lamina dura, root resorption, obturation) during post-treatment examinations with a mean follow up of 26 months. RESULTS: Clinical evaluation at follow up found ET outcome was successful in 88%, questionable in 10% (tenderness with percussion, mobility, widened ligament), and a failure in 2% (developed lesion after ET). Periapical lesions were present in 37% of cases (mean lesion size 6.2 mm). Following ET, mean lesion size (1.8 mm) had decreased by 71%. Obturation was evaluated as optimal or acceptable in 68%. Radiographic evaluation was considered successful in 80%, no change in 15%, and a failure in 5%. CONCLUSIONS: Despite obturation deficiencies and the immunocompromised state of the patients, endodontic therapy has a relatively high degree of success in the majority of HIV/AIDS patients. HIV infection and AIDS should not be considered as a contraindication to endodontic therapy in this patient population.

Adult↗
PubMed1991

Influence of chest physiotherapy on arterial oxygen saturation.

Two groups of ventilated patients were compared for chest physical therapy on an ICU: respiratory insufficient patients on one side and a control population on the other were submitted either to percussion or vibration therapy, and to postural drainage. Our data show a decrease in arterial oxygen saturation after CPT and after 2h monitoring; the lateral position results in a better SaO2 in the pneumonia group while SaO2 tend to decrease in the control population. However, no significant therapeutic influence of vibration nor percussion was found. Our data suggest CPT does not result in a short term respiratory benefit. Further investigations with prolonged sessions of postural drainage are required.

Adult↗
PubMed1977

Tendon reflex latencies in the upper extremity.

This study was aimed at establishing a baseline for the latency values of the biceps-brachii, triceps-brachii and brachioradialis tendon reflexes from the moment of elicitation by percussion of the tendon, to the appearance of the muscle action potential. The percussion hammer triggered the electronic sweep on the electromyograph oscilloscope, showing latency to the onset of the potential. Standard skin electrodes were used. Certain precautions were taken to avoid artifacts caused by skin movement. Thirty normal volunteer subjects, between the ages of 17 and 55 years, were examined. Biceps reflex latency values varied between 9 and 14 msec; with a mode of 11 msec and an average of 11 msec. Triceps latency values varied between 9 and 13 msec; with a mode of 11 msec and an average of 10 msec, and brachioradialis latency values varied between 13 and 20 msec, with a mode of 16 msec and an average of 16 msec.

Action Potentials↗
PubMed1991

[Peculiarities of occupational health vibration measurements of manually controlled banging machines].

Specific problems of the measurement of mechanical vibrations on the grips of hand-held tools are discussed in this paper. Especially the measurement on percussive-typ tools, e.g. pneumatic hammers, percussive drills and others, is focussed. The possibilities of affecting the measuring results because of mistakes in the measurement procedure and because of technological peculiarities of the working process are explained and hints for minimizing these influences are given.

Bone Diseases↗
PubMedDate not supplied

[The morphological characteristics of the brain injuries in acceleration trauma depending on the conditions of its occurrence].

The series of 175 cases of cranio-cerebral trauma (acceleration trauma by mechanism of its formation) was studied. Morphology of percussion and anti-percussion cerebral lesions was shown to depend on conditions of trauma formation and other factors including presence or lack of cranial bone fractures, cerebral vascular pathology, nature of trauma (isolated or combined) etc.

Acceleration↗