Absence Of Spontaneous Recovery Research Articles

Liver Failure in the Critical Care Setting

Acute liver failure (ALF) can be challenging to manage due to the effect of liver failure on other organs and the severity of illness that ensues. Both the practicing surgeon and the intensivist should be aware of the manifestations, workup, and management implications as ALF is not uncommon to many intensive care settings. ALF precipitates a severe multiorgan dysfunction syndrome in a majority of cases, with high rates of complications and an elevated risk of death. Management requires a systemic approach in addition to the collaboration of a multidisciplinary team with an emphasis on early recognition, prompt management of complications, and timely transfer to a transplant center. In the absence of spontaneous recovery, transplantation is the only definitive management option and may not always be feasible or immediately available. The continuing search to develop alternatives is essential. This review contains 2 figures, 9 tables and 70 references Keywords: acetaminophen, acute liver failure, cerebral edema, coagulopathy, hepatitis, jaundice, N-acetylcysteine, transplantation

Acute Liver Failure

Acute liver failure (ALF) can be challenging to manage due to the effect of liver failure on other organs and the severity of illness that ensues. Both the practicing surgeon and the intensivist should be aware of the manifestations, workup, and management implications as ALF is not uncommon to many intensive care settings. ALF precipitates a severe multiorgan dysfunction syndrome in a majority of cases, with high rates of complications and an elevated risk of death. Management requires a systemic approach in addition to the collaboration of a multidisciplinary team with an emphasis on early recognition, prompt management of complications, and timely transfer to a transplant center. In the absence of spontaneous recovery, transplantation is the only definitive management option and may not always be feasible or immediately available. The continuing search to develop alternatives is essential. This review contains 2 figures, 9 tables and 70 references Keywords: acetaminophen, acute liver failure, cerebral edema, coagulopathy, hepatitis, jaundice, N-acetylcysteine, transplantation

Audio-Visual Stimulation Improves Visual Search Abilities in Hemianopia due to Childhood Acquired Brain Lesions.

Results obtained in both animal models and hemianopic patients indicate that sound, spatially and temporally coincident with a visual stimulus, can improve visual perception in the blind hemifield, probably due to activation of 'multisensory neurons', mainly located in the superior colliculus. In view of this evidence, a new rehabilitation approach, based on audiovisual stimulation of visual field, has been proposed, and applied in adults with visual field reduction due to unilateral brain lesions. So far, results have been very encouraging, with improvements in visual search abilities. Based on these findings, we have investigated the possibility of inducing long-lasting amelioration also in children with a visual deficit due to acquired brain lesions. Our results suggest that, in the absence of spontaneous recovery, audiovisual training can induce activation of visual responsiveness of the oculomotor system also in children and adolescents with acquired lesions and confirm the putatively important role of the superior colliculus (SC) in this process.

Preclinical Evaluation of Reconsolidation Blockade by Clonidine as a Potential Novel Treatment for Posttraumatic Stress Disorder

Exposure to traumatic events can lead to posttraumatic stress disorder (PTSD). Current PTSD treatments typically only produce partial improvement. Hence, there is a need for preclinical research to identify new candidate drugs and to develop novel therapeutic approaches. Animal studies have indicated that fear memories can be weakened by blocking restabilization after retrieval, a process known as reconsolidation. Furthermore, evidence suggests that there are important alterations of the noradrenergic system in PTSD, and hence it may be of interest to study drugs that target this pathway. Here, we investigated the efficacy of clonidine, an α₂-adrenoreceptor agonist, to block reconsolidation in an animal model of persistent traumatic memories. Using an auditory fear conditioning paradigm in rats, we tested the efficacy of clonidine to weaken fear memory retention when administered systemically after retrieval. We evaluated dosage, number of treatments, and specificity in reconsolidation blockade. We found that postretrieval administration of clonidine disrupts fear-related memories in a dose-dependent manner and that two treatments are sufficient for maximal memory impairment. Furthermore, we determined that this effect is long lasting and specific to reconsolidation processes as shown by the selectivity to affect reactivated memories and the absence of spontaneous recovery and of postreactivation short-term memory impairment. Our results demonstrate the efficacy of systemic administration of clonidine following retrieval to persistently disrupt fear memory retention through reconsolidation blockade. This study provides important preclinical parameters for future therapeutic strategies involving clonidine to block reconsolidation as a novel treatment for PTSD symptoms.

Isolated paralysis of the serratus anterior muscle successfully treated by surgical release of the distal portion of the long thoracic nerve

Objectives Isolated paralysis of the serratus anterior (SA) muscle had been reported, especially in athletes. During SA fascial flap dissections, we observed that fascial and vascular structures can mechanically constrain the thoracic portion of the long thoracic nerve (LTN). Here, we assess the results of neurolysis of the thoracic segment of the LTN. Methods A prospective multicenter study was conducted between December 1999 and June 2004. Every case of isolated palsy of the SA was included, after a Parsonage-Turner syndrome has been ruled out. Eighteen consecutive cases underwent such neurolysis. There were 14 men and 4 women. Their mean age was 30 years (17 to 49). Results The operation took place 16.4 months (range, 4-72 months) after the onset of palsy. Pain relief usually occurred during the first postoperative month. At the longest follow-up most patients had recovered completely. Conclusions In the absence of spontaneous recovery from traumatic palsy, surgical release of the distal segment of the LTN is a minimally invasive, safe and efficient procedure. Results were best when surgery was performed within six months of the initial paralysis.

Lingual nerve injury: II. Observations on sensory recovery after micro-neurosurgical reconstruction

The aim of this study was to report on neurosensory recovery after micro-surgical lingual nerve repair, and to evaluate the effect on recovery of age, delay in repair and gender of the patient. Seventy-four patients entered the study. The micro-surgical repair performed was direct nerve suture ( n = 71), external neurolysis ( n = 2) and excision of neuroma without nerve coaptation ( n = 1). A standardized neurosensory examination was employed in all patients before surgery and during follow up. Recovery was significant for perception of all tested stimuli: feather light touch, pin prick, pointed/dull discrimination, warm, cold, location of touch, and brush stroke direction, pain perception and two-point discrimination. The rate of recovery was highest during the first 6 months. Females were more often affected than males, but recovery was not influenced by gender. The distribution of neurogenic discomfort (paraesthesia, etc.) remained essentially unchanged. Disregarding cases with poor recovery, delay of surgery had a small but significant influence on the regain of neurosensory function of the lingual nerve whereas age had no such effect. None of the patients recovered to normal. Lingual nerve injury seriously affects the quality of life of patients, and micro-surgical repair is beneficial in the absence of spontaneous recovery.

Morphometric study of the cervical course of the hypoglossal nerve and its application to hypoglossal facial anastomosis.

The hypoglossal nerve is used classically in salvage of facial paralyses in the absence of spontaneous recovery. A variety of ways of transferring and suturing the hypoglossal nerve to the distal segment of the facial nerve have been reported. In order to determine which mode of reconstruction is the best for neurotisation of the facial nerve, the caliber of the hypoglossal nerve was studied in ten subjects at the level of proximal and distal parts of the trunk and the cervical loop. The fascicular surface area of the cervical branch is inadequate for use. The distal extremity of the hypoglossal nerve has an ideal caliber to be sutured to the facial nerve trunk and the proximal part is large enough to allow partial harvesting of the hypoglossal nerve for neurotisation of the facial nerve.

27-Year-Old Woman With Pancytopenia

A 27-year-old woman had a 4-week history of progressive dyspnea on exertion, palpitations, light-headedness during activity, and frontal headache. She denied having fever, cough, chest pain, or vertigo. Hematologic studies showed a hemoglobin concentration of 5.0 g/dL, a mean corpuscular volume of 102.9 fL, a total leukocyte count of 4.3 x 109/L (differential: neutrophils, 1.35 x 109; lymphocytes, 2.54 x 109; mononuclear cells, 0.39 x 109; eosinophils, 0.01 X 109; and basophils, 0.01 X 109),and a platelet count of 115 X 109/ L. She was hospitalized for further assessment. The patient's past medical history was remarkable for a chronic generalized seizure disorder; the last tonic-clonic seizure had occurred 3 months before the current admission. She experienced absence seizures daily. One episode of streptococcal pharyngitis was treated with orally administered penicillin 4 months before the current examination. Medications included valproic acid, 1 g/day in divided doses (a regimen that had been used for 7 years), and felbamate, 1,200 mg three times daily (therapy that had been initiated 7 months before hospitalization). She used nonprescription aspirin preparations for headaches. The patient had no family history of hematologic disorders, and a complete blood cell count performed 8 months previously had shown normal results. Menses were normal, and no other overt source of blood loss was identified. The patient had never received chemotherapy or radiation treatment, and no exposure to toxins was elicited. Physical examination revealed a resting tachycardia of 110 beats/min and a normal blood pressure, respiratory rate, and temperature. Pallor was noted. A grade 2 (on the basis of 1 to 6) systolic murmur was heard over the precordium. No adenopathy, splenomegaly, or neurologic deficit was detected. Two painless ecchymoses, each less than 5 em in diameter, were seen over the left deltoid muscle and anterior aspect of the thigh. On admission, an electrolyte panel, liver

Neuronal conditioned responses in the dorsal hippocampus to combined acoustic stimulation and extracellular polarization

1. Responses of dorsal hippocampal neurons were investigated during combinations of an acoustic stimulus with a direct current (anode), stimulating the cell through the recording microelectrode. Of the 45 cells, 22% formed conditioned responses of activation or inhibitory types which corresponded with the character of the reinforcing agent. Cells not responding to the stimuli did not form temporary connections. Approximately half of the conditionally responding neurons formed extinction and differentiation to an unreinforced stimulus. 2. During periodic presentation of combinations of acoustic and electrical stimulation 30% of the 25 cells formed conditioned responses to time. Significant trace reproduction of conditioned responses was observed during 10 to 12 omissions of the stimuli. Cells forming ordinary conditioned responses could produce conditioned responses to time also. They were formed more rapidly. 3. Prolonged periodic presentation of the acoustic stimulus leads to rhythm binding of the previous stimulation. These responses differ from conditioned responses to time in their short duration, the absence of spontaneous recovery of the responses, and their occurrence within a definite time interval. 4. It is suggested that the characteristics discovered during the formation of simple temporary connections and observed in various model situations in neurons belonging to different brain structures are common to many conditioned-reflex acts.