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PubMed2003

A saturated-fat diet aggravates the outcome of traumatic brain injury on hippocampal plasticity and cognitive function by reducing brain-derived neurotrophic factor.

We have conducted studies to determine the potential of dietary factors to affect the capacity of the brain to compensate for insult. Rats were fed with a high-fat sucrose (HFS) diet, a popularly consumed diet in industrialized western societies, for 4 weeks before a mild fluid percussion injury (FPI) or sham surgery was performed. FPI impaired spatial learning capacity in the Morris water maze, and these effects were aggravated by previous exposure of the rats to the action of the HFS diet. Learning performance decreased according to levels of brain-derived neurotrophic factor (BDNF) in individual rats, such that rats with the worst learning efficacy showed the lowest levels of BDNF in the hippocampus. BDNF immunohistochemistry localized the decreases in BDNF to the CA3 and dentate gyrus of the hippocampal formation. BDNF has a strong effect on synaptic plasticity via the action of synapsin I and cAMP-response element-binding protein (CREB), therefore, we assessed changes in synapsin I and CREB in conjunction with BDNF. Levels of synapsin I and CREB decreased in relation to decreases in BDNF levels. The combination of FPI and the HFS diet had more dramatic effects on the active state (phosphorylated) of synapsin I and CREB. There were no signs of neurodegeneration in the hippocampus of any rat group assessed with Fluoro-Jade B staining. The results suggest that FPI and diet impose a risk factor to the molecular machinery in charge of maintaining neuronal function under homeostatic and challenging situations.

Animals↗
PubMed1992

Assessment of the ruminant respiratory system.

With practice, complete use of the methods of this assessment: history, detailed examination of the head and neck, cough induction, chest auscultation and percussion, and chest auscultation following forced rebreathing can be completed within 10 minutes. The examination can provide a great deal of new information regarding the respiratory system that would go undetected on a more general physical examination. In cases in which the diagnosis is still in question or requires confirmation, this will also enable the optimal use of appropriate ancillary tests, as described in the article on ancillary testing for the respiratory tract elsewhere in this issue.

Animals↗
PubMed2003

Comparison of preoperative pain and medication use in emergency patients presenting with irreversible pulpitis or teeth with necrotic pulps.

OBJECTIVE: This retrospective study compared differences in preoperative pain and medication use in patients with moderate to severe pain who sought emergency endodontic care for teeth with irreversible pulpitis and for symptomatic teeth with necrotic pulps. STUDY DESIGN: A total of 323 patients seeking emergency endodontic treatment completed questionnaires regarding their biographical information, pain, pain history, and medications. Teeth were tested for vitality, mobility, percussion, and palpation pain. Lymphadenopathy was also evaluated. RESULTS: Patients with irreversible pulpitis waited significantly (P <.05) longer before seeking emergency care (9 days vs 4 days) than patients with symptomatic teeth with necrotic pulps. No differences (P >.05) were found between the groups in terms of analgesic or antibiotic use and pain relief from preoperative narcotic medications. Nonnarcotic analgesics were reported to significantly reduce pain more often in patients with symptomatic teeth with necrotic pulps. There were sex differences in the group of patients with irreversible pulpitis: More women than men were taking analgesic medications and, in the group having symptomatic teeth with necrotic pulps, more men than women reported pain relief from their analgesic medications. CONCLUSION: Patients with irreversible pulpitis wait longer to seek emergency treatment. A majority (81%-83%) of emergency patients with moderate to severe pain will have taken some type of medication(s) to help control their pain, and more women than men with irreversible pulpitis will take an analgesic. By taking their preoperative medication(s), this group of patients will get relief 62% to 65% of the time; furthermore, more men than women with symptomatic teeth with necrotic pulps will experience pain relief.

Adult↗
PubMed1996

Quantitative determination of the stability of the implant-tissue interface using resonance frequency analysis.

Bone anchored implants are now being used in dentistry for supporting intraoral and craniofacial prostheses. Although high success rates have been reported, a small number of implants may fail during the early healing phase or lateral in function. Currently available clinical methods to determine implant stability and osseointegration are relatively crude and may entail percussing a fixture with a blunt instrument. Radiographs are of value, but a standardised technique is necessary to ensure repeatability. This investigation was designed to study the application of a non-invasive test method using resonance frequency analysis to make quantitative measurements of the stability of the implant tissue interface in-vitro and in-vivo. The resonance frequency of a small transducer was measured when attached to implants embedded at different heights in an aluminum block. A strong correlation (r = 0.94, p < 0.01) was observed between the observed frequency and the height of implantation fixture exposed. The change in stiffness observed in the bone surrounding an implant during healing was modelled by embedding implants in self-curing polymethylmethacrylate and measuring the resonance frequency at periods during polymerisation. A significant increase in resonance frequency was observed related to the increase in stiffness. Resonance frequency measurements were also made on implants in-vivo and the results correlated well with the in-vitro findings.

Biomechanical Phenomena↗
PubMed2000

Periodontal healing after intentional auto-alloplastic reimplantation of injured immature upper front teeth.

BACKGROUND/AIMS: Conventional endodontic treatment results in high complication quota when performed in immature teeth. Intentional reimplantation with extraoral insertion of an endodontic implant (auto-alloplastic reimplantation) is an alternative. METHOD: In a retrospective study, the healing of 40 teeth reimplanted intentionally according to this method in patients aged 7 to 15 years was evaluated. Clinical tests (palpation, percussion sound, periotest values) and radiographical examinations were used to determine the type of periodontal healing (inflammatory resorption/periodontitis apicalis; replacement resorption/ankylosis; normal healing). RESULTS: Mean lifetime of the replanted teeth was 59.2+/-42.5 months, estimated survival time on the basis of the Kaplan-Meier analysis was 99.5 months. 17 teeth (42.5%) were classified as failures, mostly due to inflammatory resorption or periodontitis apicalis. Further investigations demonstrated that success rate and retention period of intentionally replanted teeth depend on the preoperative condition of the pulp. Teeth with preoperative infection suffered frequently from inflammatory resorption or periodontitis apicalis after being replanted (14 of 28 teeth). Estimated survival time according to Kaplan-Meier was 75.5 months. In contrast, inflammations or progressive resorptions were not observed in teeth without preoperative infection of the pulp. All these 12 teeth showed normal periodontal healing and regular tooth mobility. In the absence of any pathology in clinical or radiological findings after an average functional period of 72.3 months, the prognosis can be presumed excellent. Estimated survival time of 148.3 months according to Kaplan-Meier differs significantly from survival time of teeth infected preoperatively. CONCLUSIONS: From the results of this investigation, it may be concluded that an infection of the pulp - due to delay of treatment or attempts at endodontic therapy - should be avoided before intentional replantation of immature front teeth with pulp necrosis. Periodontal healing of the autologous root is not impaired by the insertion of posts made of Al2O3-ceramics or titanium. The inserted posts do not ankylose. Orthodontic movement of auto-alloplastically replanted teeth is possible.

Adolescent↗
PubMed2002

Treatment of replacement resorption with Emdogain--a prospective clinical study.

The present clinical study investigated the outcome of intentional replantation using Emdogain for periodontal healing following trauma-related ankylosis. Sixteen ankylosed teeth affected by replacement resorption were treated as follows: After tooth extraction, the root canal was obturated with a retrograde titanium post. Emdogain was applied to the root surface and into the extraction socket with subsequent replantation of the tooth. Evaluation parameters included horizontal and vertical Periotest scores, percussion sound and periapical radiographs. All findings were compared to those of the adjacent teeth. The mean follow-up period was 15 months (range 4-24 months). Eleven teeth showed no signs of recurrence of ankylosis: they were in full function and exhibited no pathological clinical findings. Four severely traumatized teeth demonstrated a recurrence of ankylosis after a mean period of 6 months, one tooth was lost in a second accident after 7 months. The estimated probability of 1 year without recurrence of ankylosis was P=0.66 (95% confidence interval [0.40; 0.94]). The mean survival time was 10.2 months (SD 1.1). The results indicate that treatment of replacement resorption following light to moderate trauma with replantation and Emdogain appears to prevent or delay recurrence of ankylosis in many cases.

Adolescent↗
PubMed2003

The Periotest in traumatology. Part II. The Periotest as a special test for assessing the periodontal status of teeth in children that have suffered trauma.

The research was carried out on the upper permanent incisor teeth of 101 children aged 8-12 years attending the trauma clinic at the University Dental Hospital, Manchester, UK. The double blind, cross-over study involved Periotest readings being taken by one examiner and traditional special tests being carried out by another examiner. The traditional special tests chosen were mobility testing, percussion sounds and radiographs. The Periotest readings and special tests were then repeated at the child's recall appointment. The results revealed that there was a significant difference (P < 0.001) between the number of abnormalities detected by the Periotest and those detected by the traditional special tests. There was also found to be a significant difference (P < 0.001) in the detection of undesirable sequelae between the Periotest and the traditional special tests.

Chi-Square Distribution↗
PubMed2001

Interdental wiring in jaw fractures: effects on teeth and surrounding tissues after a one-year follow-up.

Several authors have suggested that interdental wiring may have an adverse effect on the teeth and surrounding tissues. In the present study we examined 250 teeth that had been subjected to wiring and 142 adjacent teeth that had not been wired (controls). During the wiring period, and after a minimum of 1 year following treatment of the jaw fracture, the teeth and periodontal tissues were examined by periodontal probing, percussion sound test, mobility test, sensitivity test, and radiography. One tooth showed temporary increased mobility. Periodontal health was clinically and radiologically fully restored after a year in all teeth. Progressive caries was seen in 2 patients and was treated. Loss of sensitivity was seen in 3 teeth adjacent to the fracture site and in one tooth adjacent to a titanium cortical screw. However, these pulpal changes either recovered spontaneously or were treated endodontically. There were few late problems in the teeth and surrounding tissues. In 243 teeth (97%), completely healthy conditions were found in pulp and periodontium. There was no evidence of root resorption or dentoalveolar ankylosis. We conclude that late deleterious effects on the teeth and periodontal tissues from interdental wiring in the treatment of jaw fractures were uncommon 1 year after the removal of the interdental wiring.

Adolescent↗
PubMed1995

Increasing- and decreasing-loudness aftereffects: asymmetrical functions for absolute rate of sound level change in adapting stimulus.

After exposure to a tone of decreasing sound level, participants report that a steady tone increases in loudness; after exposure to an increasing sound level, they perceive a steady tone to decrease in loudness. The increasing-loudness aftereffect is the more sensitive to a difference between adapting and test frequencies, its absolute size becoming greater than that for decreasing-loudness aftereffect as frequencies are made to match. Although this asymmetry may reflect processing differences for the two directions of sound level change, a more parsimonious hypothesis entails perceived increasing loudness of short steady tones, in conjunction with differing levels of tonal adaptation across test frequencies. The former explanation is supported by the present report of another aftereffect asymmetry: With frequency the same for both adapting and test stimuli, so that tonal adaptation was nearly asymptotic during testing, altering the absolute rate of sound level change of the adapting stimulus had a greater effect on the magnitude of the increasing-loudness aftereffect. The first hypothesis is consistent with the percussive nature of natural sounds, few of which are steady: most of their sound levels rise almost instantaneously and decrease slowly.

Humans↗
PubMed1988

Traumatic brain injury in the rat: effects on lipid metabolism, tissue magnesium, and water content.

Tissue levels of free fatty acids (FFA), total phospholipid, cholesterol, thromboxane B2, water, Na+, K+, and Mg2+ were measured in rat brain after lateral fluid-percussion brain injury of moderate severity (2.0-2.2 atm). Brains of injured animals and sham-operated controls were frozen in situ with liquid N2 at 10 min, 4 h, and 24 h postinjury and removed. The left parietal cortex, which has been shown previously histologically to be the site of maximal injury, was dissected for analysis. Traumatic injury was associated with small increases in FFA levels at 10 min and 4 h and much larger increases at 24 h postinjury. Among the FFA, the largest increases were observed in stearate, arachidonate, and docosahexaenoate. Total phospholipid and cholesterol levels were decreased significantly at all experimental time points. Thromboxane levels were markedly elevated (30-fold) at 10 min posttrauma but substantially declined by 4 h and approached control values at 24 h. Total Mg2+ levels were significantly below control values at 4 h and 24 h posttrauma. No changes in water content were observed at any of these time points. Small decreases in tissue K+ occurred at 4 h; tissue Na+ levels were found to be slightly increased only at 24 h. These results are consistent with the hypothesis that changes in lipid metabolism and Mg2+ content of brain after injury may play a role in the pathophysiology of irreversible, posttraumatic tissue damage. In contrast, significant edema formation does not occur in this model and does not, therefore, appear to be a factor in the injury process.

Animals↗
PubMed1991

Evaluation of memory dysfunction following experimental brain injury using the Morris water maze.

Memory dysfunction, a common clinical feature of traumatic brain injury (TBI), is thought to be related to secondary damage of key anatomic structures in the brain, including the hippocampus. In the present study, we have characterized and evaluated a novel experimental paradigm using the Morris water maze (MWM) technique, to measure post-TBI memory retention after lateral (parasagittal) fluid percussion (FP) brain injury in rats. Male Sprague-Dawley rats (n = 37) received a total of 20 training trials over 2 days in the MWM. Two and a half hours after the last training trial, the animals received FP brain injury of moderate severity (2.3 atmospheres, n = 12), high severity (2.6 atm, n = 13), or no injury (n = 12). Forty-two hours after FP brain injury, we observed a highly sufficient memory dysfunction in animals from both injury groups compared to the uninjured group (p less than 0.001). The degree of memory dysfunction was found to be directly related to the severity of injury, with the high severity group scoring significantly worse than the moderately injured group (p = 0.15). In addition, hippocampal cell loss was observed after brain injury, but only unilaterally. These data suggest that lateral FP brain injury causes memory dysfunction possibly related to concurrent hippocampal cell loss and that posttraumatic memory deficits may be sensitively quantitated using the memory testing paradigm described.

Animals↗
PubMed1992

Endothelium-dependent responses after experimental brain injury.

We examined the effect of fluid percussion brain injury on the responses to topical application of acetylcholine and serotonin, two vasoactive agents that have endothelium-dependent effects, in anesthetized cats equipped with cranial windows. Before brain injury, topical acetylcholine dilated both small and large arterioles. Thirty minutes after brain injury, acetylcholine constricted small arterioles, and the vasodilator response of large vessels was abolished. Subsequent application either of superoxide dismutase plus catalase to eliminate superoxide and hydrogen peroxide or of deferoxamine, an agent that scavenges iron and inhibits the production of hydroxyl radical via the Haber-Weiss reaction, restored the normal vasodilator responses to acetylcholine. Serotonin constricted both large and small arterioles before brain injury. After brain injury, small arterioles responded with a small vasodilation, and the response of large arterioles was abolished. After application of superoxide dismutase and catalase, the normal vasoconstrictor response to serotonin was restored. The results show that endothelium-dependent vasodilation from acetylcholine is eliminated by brain injury by a mechanism that involves the generation of oxygen radicals, and, more specifically, the production of hydroxyl radical. The results with serotonin are explained by the elimination by oxygen radicals of a vasoconstrictor agent generated by this agent, perhaps an endothelium-derived contracting factor.

Acetylcholine↗
PubMed1992

Continuous monitoring of posttraumatic cerebral blood flow using laser-Doppler flowmetry.

Traumatic brain injury causes alterations in cerebral blood flow that are thought to influence secondary pathophysiology and neurologic outcome in humans. Since it is difficult to study early changes in blood flow in head-injured patients, animal models of brain injury must be employed. However, techniques to monitor brain blood flow in animals are labor intensive and generally provide discontinuous flow measurements. The present study examines the application of laser-Doppler flowmetry for measurement of cerebral blood flow following experimental brain injury. This method allows continuous monitoring of local cerebral blood flow before, during, and after injury. Rats (n = 9) were prepared for lateral fluid percussion injury under barbiturate anesthesia. Injury (2.10 +/- 0.02 atm) was induced over the right parietal cortex, and blood flow was monitored in the contralateral cortex. Seconds after the peak hypertension after injury, blood flow in the left parietal cortex increased 226% +/- 18% (means +/- SEM). This increase was transient, with blood flow falling below control values within minutes. Five minutes after injury, blood flow was 83% +/- 8% of control, and at 1 h, this value had fallen to 56% +/- 6%. Blood flow at 60 min was 93% +/- 5% of control in the sham-injured group (n = 10). The reduction in cerebral blood flow in our laser-Doppler study was of similar magnitude as previously reported in rats injured at a similar intensity when blood flow was examined with radiolabeled microspheres. Given these results, we believe laser-Doppler flowmetry can be used to continuously monitor posttraumatic blood flow following experimental brain injury.

Animals↗
PubMed1994

Traumatically induced altered membrane permeability: its relationship to traumatically induced reactive axonal change.

Recent studies have suggested that severe forms of traumatic brain injury (TBI) can be associated with direct alterations of the axolemma. The present study evaluated whether injuries of mild to moderate severity are associated with comparable change. To this end, we used extracellular horseradish peroxidase (HRP) to determine if altered axolemmal permeability occurred following the traumatic event. Adult cats received intrathecal infusions of peroxidase and then were prepared for mild to moderate fluid percussion injury. At intervals ranging from 5 min to 3 h, animals were perfused with aldehydes and prepared for the histochemical visualization of the peroxidase, in addition to the immunocytochemical visualization of the neurofilament 68 kD subunit, a long recognized marker of reactive axonal change. The histochemically and immunocytochemically prepared tissue was examined at both the light and electron microscopic level. With mild TBI, the injured animals displayed a repertoire of neurofilament misalignment and axonal swelling consistent with that previously described in our laboratories, yet these changes were not associated with the passage of peroxidase from the extracellular to the intraaxonal compartment. With moderate injury, on the other hand, focal axolemmal permeability change to the extracellularly confined peroxidase was recognized. This peroxidase passage was associated with local mitochondrial abnormalities in addition to an increased packing of the neurofilaments. Over a 3 h course, these neurofilaments began to disassemble, showing a delayed progression of reactive axonal change. Collectively, the results of this investigation suggest that traumatically induced axonal injury involves complex subsets of pathobiology, one evoking rapid primary neurofilamentous change and misalignment, the other eliciting altered membrane permeability concomitant with rapid neurofilament compaction, leading to a delayed progression of reactive axonal change.

Animals↗
PubMed1997

Time course of cerebral edema after traumatic brain injury in rats: effects of riluzole and mannitol.

Brain trauma is the main cause of morbidity and mortality in young adults. One delayed events that occurs after a head trauma and compromises the survival of patients is cerebral edema. The present study examined first the occurrence of cerebral edema after a traumatic brain injury (TBI) induced by moderate fluid percussion in rats. Brain water content was measured from 1 h to 7 days posttrauma, in the hippocampus and cortex, on both ipsi- and contralateral hemispheres. Second, the effects of mannitol, an osmotic agent frequently used in the clinic, and riluzole, a neuroprotective compound, were investigated on regional edema formation. After TBI, the ipsilateral edema began early at 1-6 h, was maximal at 48 h and was resorbed by 5-7 days. No edema was observed in the contralateral hemisphere. Mannitol at 1 g/kg or vehicle was administered iv 15 min, 2 h and 4 h postinjury. At this dose, mannitol significantly attenuated the ipsilateral injured cortex edema measured at 6 h (p < 0.05). Riluzole at 4 and 8 mg/kg or vehicle was administered 15 min (IV) and 6 h, 24 h, and 30 h (SC) post-TBI. Riluzole at 4 x 4 mg/kg significantly reduced edema measured at 48 h, in the ipsilateral hippocampus (p < 0.05), whereas at 4 x 8 mg/kg, the reduction was observed in the hippocampus (p < 0.01) and the injured cortex (p < 0.05). Our results demonstrate that (1) cerebral edema begins early after the injury and is resorbed over 1 week; (2) mannitol could attenuate cerebral edema; and (iii) riluzole in addition to its neuroprotective effects reduces the brain edema. Thus, riluzole could be useful in human TBI treatment.

Animals↗
PubMed1976

A study of inflatable cuffs on endotracheal tubes. Pressures exerted on the trachea.

A simple method of measuring the pressure exerted by the cuff of an endotracheal tube on the trachea is described and has been used to measure the pressures exerted by 16 commercially available cuffs on the wall of a model trachea. The Shiley, Portex soft-seal, Kamen-Wilkinson (Bivona Fome) tubes had the lowest tracheal wall pressures. Using this method in vivo the changes in tracheal wall pressure exerted by a low-pressure cuff during percussion and vibration physiotherapy, and when the patient "fights the ventilator", were recorded.

Humans↗
PubMed1982

Radionuclide assessment of the effects of chest physical therapy on ventilation in cystic fibrosis.

This study assesses the use of krypton 81m scintigraphy as a measurement tool in evaluating the effectiveness of bronchial drainage with percussion and vibration on peripheral ventilation in patients with cystic fibrosis. Ten patients with cystic fibrosis participated. Each patient underwent a krypton 81m ventilation study and traditional pulmonary function tests. Forty-five minutes later, these studies were repeated before and after a chest physical therapy treatment. Each patient acted as his own control. All krypton 81m scintiscans were recorded and analyzed visually and numerically using a digital computer to assess distribution of ventilation. Visual analysis of the scintiscans indicated individual variation in treatment response: in some patients ventilation improved with therapy; in others, no change was noted; still others had changes independent of treatment. Numerical data derived from the scintiscans and pulmonary function tests showed no important differences among the three studies of each patient. Airway abnormalities characteristic of cystic fibrosis, progression of the disease, sputum production, or a combination of these factors may account for the individual variation in response to treatment. Krypton 81m scintigraphy is a reliable measure of regional ventilation and should be useful for assessing the efficacy of chest physical therapy because of the consistent, high quality visual data retrieved.

Adolescent↗
PubMed1993

Endometriosis and ascites.

A 29-year-old black woman had increasing abdominal girth, dullness to percussion, and an irregular mass in the left adnexal region. At laparotomy, 6 L of dark brown fluid was removed, and the abdominal cavity had the appearance of extensive carcinomatosis. Subsequent histology was consistent with endometriosis. Fourteen cases of endometriosis producing symptoms resembling ovarian cancer have been previously reported. Of the 10 patients whose race was mentioned, 9 were black, as was our patient. The etiology of the ascites is unknown. Histologically, the endometrial implants show dense stroma and a slightly hyperplastic epithelium rather than the physiologic proliferative endometrium usually associated with endometriosis. This leads us to question the prognosis of the lesion despite its apparently benign histology.

Adult↗