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(1/2085) Optimization of magnesium therapy after severe diffuse axonal brain injury in rats.

A number of studies have demonstrated that magnesium salts given after traumatic brain injury improve subsequent neurologic outcome. However, given that these earlier studies have used a number of different salts, dosages, and routes of administration, follow-up studies of the neuroprotective properties of magnesium are complicated, with comparisons to the earlier literature virtually impossible. The present study has therefore characterized the dose-response characteristics of the most commonly used sulfate and chloride salts of magnesium in a severe model of diffuse traumatic axonal injury in rats. Both magnesium salts improved neurologic outcome in rats when administered as a bolus at 30 min after injury. The i.v. and i.m. optima of each salt was 250 micromol/kg and 750 micromol/kg, respectively. The identical concentrations required for improved neurologic outcome suggest that improvement in outcome was dependent on the magnesium cation and not the associated anion. Subsequent magnetic resonance studies demonstrated that the administered magnesium penetrated the blood-brain barrier after injury and resulted in an increased brain intracellular free magnesium concentration and associated bioenergetic state as reflected in the cytosolic phosphorylation potential. Both of these metabolic parameters positively correlated with resultant neurologic outcome measured daily in the same animals immediately before the magnetic resonance determinations.  (+info)

(2/2085) Association of hyperdense middle cerebral artery sign with clinical outcome in patients treated with tissue plasminogen activator.

BACKGROUND AND PURPOSE: The hyperdense middle cerebral artery sign (HMCAS) is a marker of thrombus in the middle cerebral artery. The aim of our study was to find out the frequency of the HMCAS, its association with initial neurological severity and early parenchymal ischemic changes on CT, its relevance to clinical outcome, and the efficacy of intravenous recombinant tissue plasminogen activator (rtPA) in patients with the HMCAS. METHODS: Secondary analysis of the data from 620 patients who received either rtPA or placebo in the European Cooperative Acute Stroke Study I (ECASS I), a double-blind, randomized, multicenter trial. The baseline CT scans were obtained within 6 hours from the onset of symptoms. Functional and neurological outcomes were assessed using the modified Rankin Scale and the Scandinavian Stroke Scale at day 90. RESULTS: We found an HMCAS in 107 patients(17.7%). The initial neurological deficit was more severe in patients with the HMCAS than in those lacking this sign (P<0.0001). Early cerebral edema and mass effect were also more common in patients with the HMCAS (P<0.0001). The HMCAS was related to the risk of poor functional outcome (grade of 3 to 6 on the modified Rankin Scale) on univariate analysis: 90 patients (84%) with the HMCAS and 310 patients (62%) lacking this sign were dependent or dead at day 90 (P<0.0001). However, this association was no longer significant in a logistic model accounting for the effect of age, sex, treatment with rtPA, initial severity of neurological deficit and early parenchymal ischemic changes on CT. Patients with the HMCAS who were given rtPA had better neurological recovery than those who received placebo (P=0.0297). CONCLUSIONS: The HMCAS is associated with severe brain ischemia and poor functional outcome. However, it has no significant independent prognostic value when accounting for the effect of initial severity of neurological deficit and of early parenchymal ischemic changes on CT. Patients with the HMCAS may benefit from intravenous rtPA.  (+info)

(3/2085) Possible sources of discrepancies in the use of the Semmes-Weinstein monofilament. Impact on prevalence of insensate foot and workload requirements.

OBJECTIVE: The purpose of this study was to evaluate the effects of different testing sites and buckling strengths on the sensitivity and specificity of using the Semmes-Weinstein monofilament to detect patients with insensate foot. The impact on workload required to educate and follow up these high-risk individuals was estimated by modeling in our patient population with a documented status of neuropathy. RESEARCH DESIGN AND METHODS: Using the 5.07/10-g monofilament, one observer tested 132 randomly selected subjects with diabetes at five sites on the right foot. The sensitivity and specificity of each site and combinations of sites in detecting vibration perception threshold > 40 was calculated. In addition, two monofilaments, one with a buckling force of 5 g and the other with a force of 15 g, were compared by testing 200 randomly selected patients. An estimate of the prevalence of insensate foot and workload was made by modeling the findings to the 5,270 patients with neuropathy status registered on our computerized database. RESULTS: Specificity of the 5.07/10-g monofilament to detect insensate foot at each of the five sites is high, at approximately 90%, but there is considerably more variation and lower sensitivity, ranging from 44-71%. Data derived from the use of different combinations of sites showed that more stringent criteria are associated with lower sensitivity but higher specificity. If the foot is considered insensate when either of sites 3 and 4 (plantar aspect of the first and fifth metatarsal heads, respectively) cannot feel the monofilament, there is reasonable sensitivity and specificity (80-86%, respectively). By modeling on our diabetes center population, it can be demonstrated that the choice of different methodologies leads to different conclusions about the prevalence of severe neuropathy, ranging from 3.4 to 29.3%. CONCLUSIONS: Using a combination of sites 3 and 4 for monofilament testing gives a reasonable compromise for time, sensitivity, and specificity. Minor changes in sensitivity and specificity can lead to major changes in the prevalence of neuropathy, with implications for workload.  (+info)

(4/2085) Incidence of cranial ultrasound abnormalities in apparently well neonates on a postnatal ward: correlation with antenatal and perinatal factors and neurological status.

AIM: To evaluate cranial ultrasonography and neurological examination in a cohort of infants regarded as normal; and to determine the prevalence of ultrasound abnormalities and any potential association with antenatal or perinatal factors or deviant neurological signs. METHODS: Cranial ultrasound findings and neurological status were evaluated in 177 newborns (gestational age 36.3 to 42 weeks), admitted to a postnatal ward directly after birth and regarded as normal by obstetric and paediatric staff. The age of the infants at the time of examination ranged between 6 and 48 hours. Ultrasound abnormalities were present in 35 of the 177 infants studied (20%). Ischaemic lesions, such as periventricular and thalamic densities were the most common finding (8%), followed by haemorrhagic lesions (6%). The possible sequelae of antenatal haemorrhages, such as focal ventricular dilatation or choroid cysts, were present in 6%. Abnormal ultrasound findings were not significantly associated with signs of perinatal distress, such as cardiotocographic abnormalities or passage of meconium. Abnormal ultrasound findings tended to be associated with antenatal problems, although this did not reach significance. Ultrasound abnormalities were strongly associated with deviant patterns on the neurological examination. CONCLUSIONS: These results suggest that ultrasound abnormalities are more common than has been reported up to now. Lesions that could be ischaemic, such as flare densities, are seen even in the absence of any antenatal or perinatal risk factor.  (+info)

(5/2085) Predictive value of plasma and cerebrospinal fluid tumour necrosis factor-alpha and interleukin-1 beta concentrations on outcome of full term infants with hypoxic-ischaemic encephalopathy.

AIM: To determine the predictive value of plasma and cerebrospinal fluid (CSF) tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) concentrations on the outcome of hypoxic-ischaemic encephalopathy (HIE) in full term infants. METHODS: Thirty term infants with HIE were included in the study. HIE was classified according to the criteria of Sarnat and Sarnat. Blood and CSF were obtained within the first 24 hours of life and stored until assay. Five infants died soon after hypoxic insult. Neurological examinations and Denver Developmental Screening Test (DDST) were performed at 12 months in the survivors. RESULTS: At the age of 12 months neurological examination and DDST showed that 11 infants were normal; 14 had abnormal neurological findings and/or an abnormal DDST result. Eleven normal infants were classified as group 1 and 19 infants (14 with abnormal neurological findings and/or an abnormal DDST and five who died) as group 2. CSF IL-1 beta and TNF-alpha concentrations in group 2 were significantly higher than those in group 1. Plasma IL-1 beta and TNF-alpha concentrations were not significantly different between the two groups. IL-1 beta, but not TNF-alpha concentrations, in group 2 were even higher than those in group 1, although non-survivors were excluded from group 2. When the patients were evaluated according to the stages of Sarnat, the difference in the three groups was again significant. Patients whose CSF samples were taken within 6 hours of the hypoxic insult had higher IL-1 beta and TNF-alpha concentrations than the patients whose samples were taken after 6 hours. CONCLUSIONS: Both cytokines probably contribute to the damage sustained by the central nervous system after hypoxic insult. IL-1 beta seems to be a better predictor of HIE than TNF-alpha.  (+info)

(6/2085) Isolated dysarthria due to extracerebellar lacunar stroke: a central monoparesis of the tongue.

OBJECTIVES: The pathophysiology of dysarthria can preferentially be studied in patients with the rare lacunar stroke syndrome of "isolated dysarthria". METHODS: A single study was carried out on seven consecutive patients with sudden onset of isolated dysarthria due to single ischaemic lesion. The localisation of the lesion was identified using MRI. The corticolingual, cortico-orofacial, and corticospinal tract functions were investigated using transcranial magnetic stimulation. Corticopontocerebellar tract function was assessed using 99mTc hexamethylpropylene amine oxime-single photon emission computerised tomography (HMPAO-SPECT) in six patients. Sensory functions were evaluated clinically and by somatosensory evoked potentials. RESULTS: Brain MRI showed the lesions to be located in the corona radiata (n=4) and the internal capsule (n=2). No morphological lesion was identified in one patient. Corticolingual tract function was impaired in all patients. In four patients with additional cortico-orofacial tract dysfunction, dysarthria did not differ from that in patients with isolated corticolingual tract dysfunction. Corticospinal tract functions were normal in all patients. HMPAO-SPECT showed no cerebellar diaschisis, suggesting unimpaired corticopontocerebellar tract function. Sensory functions were not affected. CONCLUSION: Interruption of the corticolingual pathways to the tongue is crucial in the pathogenesis of isolated dysarthria after extracerebellar lacunar stroke.  (+info)

(7/2085) Incidence and importance of lower extremity nerve lesions after infrainguinal vascular surgical interventions.

OBJECTIVES: To determine the incidence of peripheral nerve lesions after arterial vascular surgery of the lower extremity. MATERIALS AND METHODS: 436 patients who underwent peripheral vascular surgery from January 1992 until December 1996 underwent a detailed postoperative neurological examination. RESULTS: 147 patients underwent profundaplasty, 140 above-knee femoropopliteal bypasses, 106 below-knee femoropopliteal bypasses and 56 femorotibial bypasses. There were 182 women and 254 men. Peripheral nerve lesions were observed in 11 patients (4%) after primary operations. 166 patients underwent reoperations (38%) and 55 of these developed nerve lesions (33%). CONCLUSIONS: Reoperation carries an 8-fold increased risk of nerve lesions compared with patients undergoing primary surgery. Detailed explanation of the risk of peripheral nerve lesions before vascular surgery of the lower limb is advisable.  (+info)

(8/2085) Periventricular leucomalacia and preterm birth have different detrimental effects on postural adjustments.

Postural adjustments during sitting on a moveable platform were assessed by means of multiple surface EMGs of neck, trunk and leg muscles and kinematics in three groups of children, aged 1 1/2-4 1/2 years. The first group consisted of 13 preterm children (born at a gestational age of 25-34 weeks), whose neonatal ultrasounds had shown distinct lesions of the periventicular white matter (PWM). The second group was the preterm control group, consisting of 13 preterm children with normal neonatal brain scans, matched to the PWM group with respect to gestational age at birth, birth weight, sex and age of postural assessment. The third group was formed by 13 healthy children born at term and matched to the PWM group with respect to sex and age at examination. In addition to the postural assessment an age-specific neurological examination was carried out. Three of the children of the PWM group developed a cerebral palsy syndrome, nine showed minor neurological dysfunction and one child was neurologically normal. In the preterm control group one child showed minor neurological dysfunction, while the remaining 12 children of this group and all children of the full-term group were neurologically normal. The postural assessment revealed that preterm birth was associated with two types of postural dysfunction. One dysfunction was related to the presence of a PWM lesion and consisted of a limited repertoire of response variation. The other dysfunction was not related to the presence of a PWM lesion, but to preterm birth itself. It consisted of a change in the ability to modulate the postural responses. Preterm children showed a higher sensitivity to platform velocity than full-term children, and they lacked the capacity to modulate EMG amplitude with respect to initial sitting position.  (+info)