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Neonatal dystrophia myotonica. Electrophysiologic studies.

The diagnosis of dystrophia myotonica was established in a boy 3 hours old, and confirmed by family study and electromyography (EMG) at 5 days. Clinical features included hypotonia, facial diparesis, "tented" upper lip, and arthrogryposis of both knees. Percussion myotonia was elicited. The EMG disclosed characteristic bursts of electrical activity that waxed and waned on muscle percussion or needle movement. The EMG may be valuable in supporting the diagnosis of dystrophia myotonica in neonates suspected of having the disease.

Abnormalities, Multiple↗

Bronchopulmonary hygiene physical therapy for chronic obstructive pulmonary disease and bronchiectasis.

BACKGROUND: Bronchopulmonary hygiene physical therapy is a form of chest physical therapy including chest percussion and postural drainage to remove lung secretions. These are applied commonly to patients with both acute and chronic airway diseases. Despite controversies in the literature regarding its efficacy, it remains in use in a variety of clinical settings. The various forms of this therapy are labour intensive and need to be evaluated. OBJECTIVES: The objective of this review was to assess the effects of bronchial hygiene physical therapy in people with chronic obstructive pulmonary disease and bronchiectasis. SEARCH STRATEGY: We searched the Cochrane Airways Group trials register and reference lists of articles up to July 1997. We also wrote to study authors. SELECTION CRITERIA: Randomised trials in which postural drainage, chest percussion, vibration, chest shaking, directed coughing or forced exhalation technique was compared to other drainage or breathing techniques, placebo or no treatment. DATA COLLECTION AND ANALYSIS: Two reviewers applied the inclusion and exclusion criteria on masked publications independently. They assessed the trial quality independently. Only data from the first arm of crossover trials were included. MAIN RESULTS: The seven included trials involved six comparisons and a total of 126 people. The trials were small and not generally of high quality. The results could not be combined as trials addressed different patient groups and outcomes. In most comparisons, bronchial hygiene physical therapy produced no significant effects on pulmonary function, apart from clearing sputum in chronic obstructive pulmonary disease and in bronchiectasis. REVIEWER'S CONCLUSIONS: There is not enough evidence to support or refute the use of bronchial hygiene physical therapy in people with chronic obstructive pulmonary disease and bronchiectasis.

Bronchiectasis↗

Dependence of the Achilles tendon reflex on the excitability of spinal reflex pathways.

Muscle afferent activity from the triceps surae was recorded during experimentally induced alterations in amplitude of the Achilles tendon jerk. No changes in the neural afferent response to tendon percussion or in the background level of neural activity occurred when the reflex response was altered by discomfort, distraction, changes in attention, or changes in the rate of tendon percussion. Reinforcement of the Achilles tendon jerk by forceful contraction of the forearm muscles did not alter the relationship between intensity of the tendon tap and amplitude of the evoked neural afferent volley. Nevertheless, such maneuvers lowered the reflex threshold and raised reflex sensitivity so that a smaller afferent volley was required to produce a tendon jerk, and an increase in the afferent volley produced a disproportionately greater increase in reflex electromyographic activity than would have occurred at rest. Reinforcement maneuvers potentiated the H-reflex but did not alter the electrically induced afferent volley or the background level of neural activity. It is concluded that these changes in reflex responsiveness occurred through intrinsic spinal mechanisms independent of the fusimotor system.

Achilles Tendon↗

Progressive myotonia in foals resembling human dystrophia myotonica.

A severe and progressive neuromuscular disorder accompanied by clinical, electrophysiological, and pathological features resembling human dystrophia myotonica was observed in three foals. This disorder was apparent as early as 1 month of age and involved progressive skeletal muscle dysfunction, initially characterized by proximal muscle hypertrophy and hypertonicity with subsequent muscle stiffness, weakness, and atrophy. Multisystem involvement was manifested in one case by testicular hypoplasia, early cataract formation, and borderline glucose intolerance. Prolonged dimpling of these large rear-limb muscles was elicited by percussion. Myotonic discharges were identified by electromyography. Percussion dimpling and the typical myotonic discharges persisted after neuromuscular blockade. Distinctive histologic muscle changes included ring fibers, sarcoplasmic mass formation, variation in fiber diameter size, and internally positioned nuclei.

Animals↗

Diffusion and high resolution MRI of traumatic brain injury in rats: time course and correlation with histology.

Although widely employed in studies of cerebral ischemia, the use of diffusion-weighted imaging (DWI) for traumatic brain injury (TBI) has been both limited and primarily confined to the first few hours after injury. Therefore, the present study examined the temporal evolution of magnetic resonance imaging (MRI) signal changes from hours to weeks after moderate fluid-percussion TBI in rats. We used isotropic diffusion along three directions and high resolution (HR) spin-echo pulse sequences to visualize DWI and HR MRI changes, respectively. Late changes were compared to histopathological and neurological outcome. A significant decrease (P<0.05) in the apparent diffusion coefficients (ADC) below preinjury levels was found in the left cortex and left hippocampus (ipsilateral to injury) at 1-2 h post-TBI. At 2 weeks post-TBI, ADCs were significantly elevated (P<0.05) above preinjury levels in both cortex and hippocampus. Regions of hypo- and hyperintensity detected in HR MRI scans also showed evidence of tissue damage by histological evaluation. Neurological assessment indicated that such changes were observed at a level of injury which produced moderate impairment 2 weeks after the insult. These results indicate that alterations in DWI and HR MRI signals occur both early (hours) and late (weeks) after lateral fluid-percussion injury. Furthermore, the study showed that DWI was sensitive to MR signal change at 1-2 h post TBI (in select ROIs), whereas HR scans showed MR signal change primarily at later time points (3-4 h and later). Moreover, regions which demonstrate late changes are associated with histological damage and neurological impairment. The study demonstrates the utility of MRI to detect early changes, in some cases, that are predictive of long-lasting damage verified histologically.

Animals↗

Post-traumatic brain hypothermia reduces histopathological damage following concussive brain injury in the rat.

The purposes of this study were (1) to document the histopathological consequences of moderate traumatic brain injury (TBI) in anesthetized Sprague-Dawley rats, and (2) to determine whether post-traumatic brain hypothermia (30 degrees C) would protect histopathologically. Twenty-four hours prior to TBI, the fluid percussion interface was positioned over the right cerebral cortex. On the 2nd day, fasted rats were anesthetized with 70% nitrous oxide, 1% halothane, and 30% oxygen. Under controlled physiological conditions and normothermic brain temperature (37.5 degrees C), rats were injured with a fluid percussion pulse ranging from 1.7 to 2.2 atmospheres. In one group, brain temperature was maintained at normothermic levels for 3 h after injury. In a second group, brain temperature was reduced to 30 degrees C at 5 min post-trauma and maintained for 3 h. Three days after TBI, brains were perfusion-fixed for routine histopathological analysis. In the normothermic group, damage at the site of impact was seen in only one of nine rats. In contrast, all normothermic animals displayed necrotic neurons within ipsilateral cortical regions lateral and remote from the impact site. Intracerebral hemorrhagic contusions were present in all rats at the gray-white interface underlying the injured cortical areas. Selective neuronal necrosis was also present within the CA3 and CA4 hippocampal subsectors and thalamus. Post-traumatic brain hypothermia significantly reduced the overall sum of necrotic cortical neurons (519 +/- 122 vs 952 +/- 130, mean +/- SE, P = 0.03, Kruskal-Wallis test) as well as contusion volume (0.50 +/- 0.14 vs 2.14 +/- 0.71 mm3, P = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Differential modulation of carbachol and trans-ACPD-stimulated phosphoinositide turnover following traumatic brain injury.

In the fluid percussion model of traumatic brain injury (TBI), we examined muscarinic and metabotropic glutamate receptor-stimulated polyphosphoinositide (PPI) turnover in rat hippocampus. Moderate injury was obtained by displacement and deformation of the brain within the closed cranial cavity using a fluid percussion device. Carbachol and (+/-)-1-Aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD)-stimulated PPI hydrolysis was assayed in hippocampus from injured and sham-injured controls at both 1 hour and 15 days following injury. At 1 hour after TBI, the response to carbachol was enhanced in injured rats by up to 200% but the response to trans-ACPD was diminished by as much as 28%. By contrast, at 15 days after TBI, the response to carbachol was enhanced by 25% and the response to trans-ACPD was enhanced by 73%. The ionotropic glutamate agonists N-methyl-D-aspartate (NMDA), and alpha-amino-3 hydroxy-5-methyl-4-isoxazolepropionate (AMPA), did not increase PPI hydrolysis in either sham or injured rats and injury did not alter basal hydrolysis. Thus, hippocampal muscarinic and metabotropic receptors linked to phospholipase C are differentially altered by TBI.

Animals↗

Efficacy of competitive vs noncompetitive blockade of the NMDA channel following traumatic brain injury.

N-methyl-D-aspartate (NMDA) receptor antagonists have been demonstrated widely to be neuroprotective in cerebral ischemia, hypoxia, and traumatic brain injury. However, although noncompetitive NMDA antagonists have typically proven efficacious under all of these conditions, competitive antagonists have not been shown to be beneficial following moderate traumatic brain injury. The present study has used phosphorus magnetic resonance spectroscopy ([31P]MRS) to examine the effects of the competitive antagonist cis-4-(phosphonomethyl) piperidine-2-carboxylic acid (CGS-19755) and the noncompetitive antagonist dextromethorphan on biochemical outcome following fluid percussion-induced traumatic brain injury in rats. Five minutes prior to induction of moderate (2.8 +/- 0.2 atm) fluid percussion brain injury, animals received either CGS-19755 (10 mg/kg iv), dextromethorphan (10 mg/kg iv), or equal volume saline vehicle. [31P]MRS spectra were then acquired for 4 h post-trauma and intracellular pH, free magnesium concentration, cytosolic phosphorylation potential, and oxidative capacity determined. Both CGS-19755-treated animals and saline treated controls demonstrated significant and sustained declines in intracellular free magnesium concentration and bioenergetic status following trauma. In contrast, administration of dextromethorphan significantly attenuated free magnesium decline and improved bioenergetic state during the post-traumatic monitoring period. These results suggest that the neuroprotective actions of NMDA antagonists following traumatic brain injury are associated with attenuation of free magnesium decline and that such actions seem to be preferentially mediated by noncompetitive blockers.

Animals↗

The effect of M1 muscarinic blockade on behavior and physiological responses following traumatic brain injury in the rat.

Dicyclomine (1 mg/kg or 10 mg/kg), scopolamine (1 mg/kg), or saline was administered intraperitoneally to rats 15 min prior to moderate fluid percussion brain injury. A variety of reflexes and responses were measured up to 60 min following injury, and body weight and several neurological measures were taken daily up to 10 days following injury. All 3 antimuscarinic treatments reduced the duration of transient behavioral suppression as assessed by these measures. It appears that blockade of the M1 muscarinic receptor can attenuate transient behavioral suppression associated with concussive brain injury. Thus, stimulation of M1 muscarinic receptors may mediate components of reversible traumatic unconsciousness following cerebral concussion. No differences were observed between saline and antimuscarinic treatments in the incidence or duration of apnea following injury. Scopolamine pretreatment significantly elevated heart rate prior to injury, but had no significant effect on the responses of heart rate and blood pressure to experimental concussion. Both doses of dicyclomine significantly reduced resting heart rate, but unlike scopolamine, significantly enhanced the cardiovascular response to fluid percussion injury. Antimuscarinic treatment significantly reduced body weight loss and certain motor deficits, including beam balance and beam walk performance, following concussive head injury. Scopolamine and both doses of dicyclomine appeared to be equally effective in reducing long-term deficits. Data from these experiments indicate that at least some of the long-term behavioral deficits following moderate levels of brain injury may involve the binding of acetylcholine to M1 muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Kynurenate is neuroprotective following experimental brain injury in the rat.

Pharmacologic inhibition of excitatory amino acid neurotransmission improves physiologic, metabolic, and neurobehavioral outcome following experimental brain trauma. However, no studies to date have demonstrated pharmacologically-induced attenuation of histopathological changes associated with experimental brain injury models. The present study examined the effects of kynurenate, an NMDA and non-NMDA receptor antagonist, on neuronal survival in the hippocampus after lateral fluid-percussion brain injury in the rat. Animals (n = 10/treatment) randomly received an intravenous injection of either kynurenate (300 mg/kg) or buffer (equal volume) 15 min following fluid-percussion brain injury of moderate severity. Two weeks after injury, animals were sacrificed and neuronal cell loss in the hippocampus was examined with Nissl staining. Selective loss of neurons in the CA3 region of the hippocampus, which has previously been characterized in this model of brain injury, was found to be significantly attenuated following kynurenate treatment (P < 0.05). These data suggest that pharmacologic compounds which are known to have beneficial effects on neurobehavioral and physiological outcome following brain injury may also significantly attenuate post-traumatic neuronal cell loss. Our results also support other recent data that pharmacological intervention with an excitatory amino acid receptor antagonist may be of therapeutic value in the treatment of brain injury.

Animals↗

Long-lasting conditioning of the human soleus H reflex following quadriceps tendon tap.

Percussion of the quadriceps tendon was used to test the hypothesis that knee extensor muscle spindle discharge initiates down-regulation of the gain of the soleus H reflex. Seven subjects participated. Soleus H reflex magnitude was observed for up to 15 s, following conditioning tendon taps of 60 N or 80 N force and 10 ms duration, with the knee at 60 degrees or 90 degrees of flexion. The tap elicited quadriceps stretch reflexes in four subjects, with a mean latency of 42 ms. The major component of the conditioning of the soleus H reflex was significant attenuation of magnitude by 30-90% of controls, starting as early as 36 ms post-percussion and lasting as long as 3-8 s. The attenuation of reflex magnitude was evident, whichever combination of duration and force of tap was used. Preceding and/or following this inhibition, there was mild facilitation. Static stretch of quadriceps also significantly reduced soleus H reflex magnitude. These results support the spindle receptor origin for the gain attenuation seen during movement. The time course of the gain attenuation suggests a spinal route, by which the spindle discharge of the heteronymous extensor muscles initiates presynaptic inhibition of transmission through the reflex pathway.

Adult↗

Relationship between opioids and activation of phospholipase C and protein kinase C in brain injury induced pial artery vasoconstriction.

Previously, it has been observed that newborn pig pial artery constriction after fluid percussion brain injury was associated with elevated CSF dynorphin and beta endorphin concentration. Additionally, brain injury reversed dynorphin-induced pial artery vasodilation to vasoconstriction. The present study was designed to characterize the relationship between opioids and activation of phospholipase C (PLC) and protein kinase C (PKC) in brain injury-induced pial vasoconstriction. Anesthetized newborn pigs equipped with a closed cranial window were connected to a percussion device consisting of a saline-filled cylindrical reservoir with a metal pendulum. Brain injury of moderate severity (1.9-2.3 atm) was produced by allowing the pendulum to strike a piston on the cylinder. Brain injury decreased pial arteriolar diameter within 10 min of injury and continued to fall progressively for 3 h (130 +/- 5, 108 +/- 4 and 102 +/- 5 microns for 0, 10 and 180 min postinjury). In contrast, the PLC inhibitor, neomycin (10(-4) M), blunted brain injury-induced pial vasoconstriction (133 +/- 4, 129 +/- 4 and 135 +/- 5 microns for 0, 10 and 180 min postinjury, respectively). Similarly, staurosporine (10(-7) M), a PKC inhibitor, also blunted brain injury-induced vasoconstriction. beta endorphin (10(-8), 10(-6) M)-induced pial artery vasoconstriction was blunted by neomycin (12 +/- 1, 19 +/- 1 vs. 2 +/- 1, 4 +/- 2% constriction before and after neomycin, respectively). Staurosporine similarly blunted beta endorphin pial constriction (10 +/- 1, 15 +/- 1 vs. 1 +/- 1, 1 +/- 1% constriction before and after staurosporine, respectively). The constrictor potential for dynorphin was also inhibited by neomycin and staurosporine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Experimental brain injury induces expression of interleukin-1 beta mRNA in the rat brain.

Cytokines have been shown to be induced following a variety of central nervous system (CNS) insults, and may play a role in the pathophysiological sequelae of CNS injury. In the present study, we characterized the regional expression of interleukin-1 beta (IL-1 beta) mRNA in specific brain regions following experimental lateral fluid-percussion traumatic brain injury (TBI) in rats. Adult Sprague-Dawley rats (n = 42) were anesthetized with sodium pentobarbital (60 mg/kg, i.p.) and subjected to lateral fluid-percussion brain injury of moderate severity (2.4 atm.) centered over the left parietal cortex, or 'sham' treatment (anesthesia and surgery without injury). Animals were sacrificed at 1, 6 and 24 h post injury, brains were removed, and tissue samples of left (injured) parietal cortex (LC), corresponding area in the contralateral right cortex (RC), cortex adjacent to injured parietal cortex (LA), corresponding adjacent area in the right cortex (RA), left hippocampus (LH) and right hippocampus (RH) were prepared. Total RNA was isolated and Northern blot hybridization was performed and the quantity of brain tissue IL-1 beta mRNA is presented as percent relative radioactivity of IL-1 beta positive macrophage RNA which was loaded on same gel.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Clinical significance of dental root canal microflora.

OBJECTIVES: Previous work by this group has shown that a significant association exists between pain and the presence of either Prevotella or Peptostreptococcus spp. in dental root canals. The aim of this study was to examine a more extensive series of canals microbiologically, to determine whether any other particular endodontic symptoms or clinical signs showed specific associations with individual bacterial species. METHODS: Seventy root canals were examined microbiologically and clinical data collected to investigate in detail such associations. RESULTS: Of the canals studied, 37 were associated with pain, 49 with tenderness to percussion, 23 with swelling, six with purulent exudate and 57 presented with wet root canals. Anaerobes were isolated from 70.3% of painful canals and from 29.7% of pain-free canals. Significant associations were found between (a) pain and either Prevotella spp. or peptostreptococci, both with P < 0.01; (b) tenderness to percussion and Prevotella spp. (P < 0.01) or anaerobes (P < 0.05); (c) swelling and Eubacterium spp. (P < 0.01), or with Prevotella spp. or Pstr. micros, both with P < 0.05; (d) purulent exudate and any one of F. necrophorum (P < 0.01), Prev. loescheii, Streptoccoccus constellatus or Bacteroides spp. (each P < 0.05); (e) wet canal and facultative anaerobes (P < 0.01), and any one of the genera of Eubacterium, Peptostreptococcus, Prevotella or Propionibacterium (each P < 0.05). CONCLUSION: It was concluded that several different endodontic clinical signs and symptoms are significantly associated with specific bacterial species.

Adult↗

Aspirin compared with acetaminophen in the treatment of fever and other symptoms of upper respiratory tract infection in adults: a multicenter, randomized, double-blind, double-dummy, placebo-controlled, parallel-group, single-dose, 6-hour dose-ranging study.

BACKGROUND: Aspirin (acetylsalicylic acid) and acetaminophen (paracetamol) are frequently used to treat fever and other symptoms of upper respiratory tract infection (URTI). Both are available over the counter for use at the standard recommended doses of 500 and 1000 mg per single use. OBJECTIVE: This study investigated the efficacy, safety profiles, and tolerability of aspirin 500 and 1000 mg and acetaminophen 500 and 1000 mg compared with placebo in adult patients with acute febrile URTI of suspected viral origin. METHODS: This was a multicenter, randomized, double-blind, double-dummy, placebo-controlled, parallel-group trial conducted in Ukraine and Russia. Patients with URTI and acute fever of > or =38.5 degrees C received a single dose of aspirin 500 or 1000 mg, acetaminophen 500 or 1000 mg, or matching placebo. Oral body temperature was measured in the clinic at specified time points up to 6 hours after dosing. The intensity of other symptoms of URTI was rated by patients at baseline and at 2, 4, and 6 hours after dosing (scale from 0 = none to 10 = severe). The primary efficacy measure was the AUC for the change in orally measured body temperature from the time of treatment (baseline) to 4 hours after dosing. Secondary outcome measures included the change in body temperature from baseline to specified time points between 0.5 and 6 hours after dosing, the difference between baseline and the lowest measured body temperature, the time to the lowest measured body temperature, and the intensity of other symptoms of URTI (ie, headache, sinus sensitivity to percussion, sore throat, achiness, and feverish discomfort). Tolerability was monitored by recording of adverse events. RESULTS: Three hundred ninety-two patients were enrolled (78 in both aspirin groups, 79 in both acetaminophen groups, 78 in the placebo group). Demographic and baseline characteristics were comparable in the 5 groups; 51% of patients were male, with a mean age of 37.4 years and a mean body weight of 74.3 kg. The AUC values for the change in body temperature 0 to 4 hours after dosing were 3.18 (95% CI, 2.78-3.57) for aspirin 500 mg, 4.26 (95% CI, 3.84-4.68) for aspirin 1000 mg, 3.13 (95% CI, 2.77-3.49) for acetaminophen 500 mg, 4.11 (95% CI, 3.73-4.49) for acetaminophen 1000 mg, and 0.76 (95% CI, 0.38-1.13) for placebo. In terms of the primary efficacy variable, all active treatments were significantly superior to placebo (P < 0.001, 1-sided t test), with no significant differences between them. Reductions in body temperature were significantly greater with the 1000-mg doses of both active treatments compared with the 500-mg doses (P< 0.001, 1-sided t test). The mean maximum temperature reductions were 1.32 degrees C, 1.25 degrees C, 1.67 degrees C,1.71 degrees C, and 0.63 degrees C in the respective treatment groups. Significant reductions were seen in the mean intensity of headache, achiness, and feverish discomfort with all active treatments at most time points (P < 0.001), but not in sinus sensitivity to percussion or sore throat. All treatments were equally well tolerated, and no clinically significant adverse events occurred. CONCLUSIONS: In this single-dose study, aspirin 500 and 1000 mg and acetaminophen 500 and 1000 mg were more effective against fever and other symptoms of URTI than placebo. Both active treatments showed dose-related efficacy, and there was no significant difference between equal doses of the 2 agents. Safety profiles and tolerability were also comparable between treatments.

Acetaminophen↗

Differential activation of ERK, p38, and JNK MAPK by nociceptin/orphanin FQ in the potentiation of prostaglandin cerebrovasoconstriction after brain injury.

Fluid percussion brain injury elevates the cerebrospinal fluid (CSF) concentration of the opioid nociceptin/orphanin FQ (N/OFQ), which potentiates vasoconstriction to the prostaglandins U 46619, a thromboxane A(2) mimic, and prostaglandin (PG)F(2a). This study investigated the role of the extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK) isoforms of mitogen activated protein kinase (MAPK) in potentiated prostaglandin vasoconstriction after brain injury and the relationship of brain injury induced release of N/OFQ to MAPK. Pial artery diameter was measured with a video microscaler by observation through a glass coverslip cranial window placed in the parietal cortex of newborn pigs. Brain injury potentiated U 46619 induced pial artery vasoconstriction but U 0126 and SB 203580 (10(-6) and 10(-5) M, respectively) (ERK and p38 MAPK inhibitors) blocked the potentiation. In contrast, administration of SP 600125 (10(-6) and 10(-5) M) (JNK MAPK inhibitor) only attenuated brain injury induced U 46619 potentiation and such responses were significantly different than that in the presence of either U 0126 or SB 203580 after FPI. Co-administration of N/OFQ (10(-10) M), the CSF concentration observed after brain injury, with U 46619 or PGF(2a) under non brain injury conditions potentiated prostaglandin vasoconstriction but U 0126 and SB 203580 blocked such potentiation. Administration of SP 600125 modestly attenuated prostaglandin potentiation by N/OFQ. These data show that activation of ERK and p38 primarily contribute to potentiation of prostaglandin constriction after brain injury. These data suggest that N/OFQ differentially activates ERK, p38, and JNK MAPK to contribute to potentiated prostaglandin vasoconstriction after fluid percussion brain injury.

Animals↗

Elevation of hippocampal MMP-3 expression and activity during trauma-induced synaptogenesis.

The matrix metalloproteinase (MMP) enzyme family contributes to the regulation of a variety of brain extracellular matrix molecules. In order to assess their role in synaptic plasticity following traumatic brain injury (TBI), we compared expression of stromelysin-1 (MMP-3) protein and mRNA in two rodent models of TBI exhibiting different levels of recovery: adaptive synaptic plasticity following central fluid percussion injury and maladaptive synaptic plasticity generated by combined TBI and bilateral entorhinal cortical lesion (TBI + BEC). We sampled the hippocampus at 7 days postinjury, targeting a selectively vulnerable brain region and a survival interval exhibiting rapid synaptogenesis. We report elevated expression of hippocampal MMP-3 mRNA and protein after TBI. MMP-3 immunohistochemical staining showed increased protein levels relative to sham-injured controls, primarily localized to cell bodies within the deafferented dendritic laminae. Injury-related differences in MMP-3 protein were also observed. TBI alone elevated MMP-3 immunobinding over the stratum lacunosum moleculare (SLM), inner molecular layer and hilus, while TBI + BEC generated more robust increases in MMP-3 reactivity within the deafferented SLM and dentate molecular layer (DML). Double labeling with GFAP confirmed the presence of MMP-3 within reactive astrocytes induced by each injury model. Semi-quantitative RT-PCR revealed that MMP-3 mRNA also increased after each injury, however, the combined insult induced a much greater elevation than fluid percussion alone: 1.9-fold vs. 79%, respectively. In the TBI + BEC model, MMP-3 up-regulation was spatio-temporally correlated with increased enzyme activity, an effect which was attenuated with the neuroprotective compound MK-801. These results show that distinct pathological conditions elicited by TBI can differentially affect MMP-3 expression during reactive synaptic plasticity. Notably, these effects are both transcriptional and translational and are correlated with functionally active enzyme.

Animals↗

Incidence and factors associated with endodontic inter-appointment emergency in a dental teaching hospital in China.

OBJECTIVE: To assess the incidence of endodontic inter-appointment emergency (EIE) in a dental teaching hospital in China, and to correlate its occurrence with preoperative and treatment parameters. METHODS: Three thousand six hundred and ninety six cases were collected at root canal treatment appointments on demographics, presenting symptoms, treatment procedures and periradicular status. The operators consisted of faculty, undergraduate students and advanced trainees. Root canals were conventionally instrumented and then medicated. No systemic medication was prescribed. In cases EIE developed between appointments, an emergency visit was arranged and active treatment was carried out. The data of EIE cases were statistically analyzed using the chi-square test and a multiple logistic regression model. RESULTS: The overall incidence of EIE was 5%, which rate was 5.5% in females and 4.3% in males. Analyses of the potential factors revealed that patient age, tooth location, preoperative percussion pain and pulp status were the most important independent variables. CONCLUSION: EIE was significantly associated with some host factors (patient age, tooth location) and presenting factors (preoperative percussion pain, pulp status).

Adult↗