bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Differential Diagnosis of Alzheimer's Disease: Conceptual and Methodological Issues
Authors: Tierney Mary C. , Reid David W. , Zorzitto Maria L. , Gary Snow W. , Fisher Rory H. , Campbell-Taylor Irene , Lewis Anthony 
Published: July 2016

Abstract:The study of Alzheimer's disease is hampered by insufficient knowledge of its cause. It can best be described as a syndrome whose clinical and pathological features, and their associations over time, need to be more carefully examined. Issues which impede our understanding of this syndrome include the lack of: (a) a singular “gold standard” for its identification; (b) longitudinal studies with appropriate comparison groups and neuropathological follow-up; and (c) standardized multifaceted clinical assessment procedures. Our awareness of the significance of these issues has led us to undertake a large-scale prospective, longitudinal investigation of 399 dementing and normal individuals at Sunnybrook Medical Centre. As a result of problems identified, it is proposed that research efforts across various Canadian centres be coordinated to best utilize available resources and expertise.
The Blood-Brain Barrier in Alzheimer's Disease
Authors: Vinters Harry V. , Pardridge William M. 
Published: July 2016

Abstract:The current evidence for and against abnormalities of the blood-brain barrier in “normal” aging and Alzheimer's disease is reviewed. Recent studies of cerebral amyloid angiopathy, a microangiopathy commonly observed in Alzheimer's disease and one suggested to result from blood-brain barrier derangement, are discussed with particular attention to the biochemical nature of the vascular amyloid material, and features it shares with the amyloid found in senile plaque cores and with neurofibrillary tangles. Modern techniques that will probably clarify blood-brain barrier pathophysiology are reviewed.
Anatomy and Pathology of the Basal Ganglia
Authors: McGeer P.L. , McGeer E.G. , Itagaki S. , Mizukawa K. 
Published: July 2016

ABSTRACT:Neurotransmitters of the basal ganglia are of three types: I, amino acids; II, amines; and III, peptides. The amino acids generally act ionotropically while the amines and peptides generally act metabotropically. There are many examples of neurotransmitter coexistence in basal ganglia neurons. Diseases of the basal ganglia are characterized by selective neuronal degeneration. Lesions of the caudate, putamen, subthalamus and substantia nigra pars compacta occur, respectively, in chorea, dystonia, hemiballismus and parkinsonism. The differing signs and symptoms of these diseases constitute strong evidence of the functions of these various nuclei. Basal ganglia diseases can be of genetic origin, as in Huntington's chorea and Wilson's disease, of infectious origin as in Sydenham's chorea and postencephalitic parkinsonism, or of toxic origin as in MPTP poisoning. Regardless of the etiology, the pathogenesis is often regionally concentrated for reasons that are poorly understood. From studies on Parkinson and Huntington disease brains, evidence is presented that a common feature may be the expression of HLA-DR antigen on reactive microglia in the region where pathological neuronal dropout is occurring.
Pharmacotherapy of Spasticity: Some Theoretical and Practical Considerations
Authors: Rice G.P.A. 
Published: July 2016

ABSTRACT:The availability of new antispasticity agents has greatly extended the therapeutic arm of the neurologist and has obviated the need for destructive neurosurgical procedures in many instances. Baclofen remains the single most useful agent, but in certain circumstances, benzodiazepines and dantrolene sodium are useful alternative or adjunctive treatments. Tizanidine has been recently introduced, and early experience with this agent appears to be favourable. A variety of new drugs are awaiting further evaluation. The effective use of these agents demands an understanding of their principal mechanisms of action, knowledge of their predictable side effects, and a familiarity with the underlying neurological disorders. The monitoring of clinical efficacy is difficult and is often dependent upon subjective evaluation. The application of electrophysiological studies might facilitate the monitoring of treatment and the prediction of optimum treatment strategies forindividual patients. The use of these pharmacological agents, from the perspective of a clinician, will be discussed.
The Physiology of Idiopathic Dystonia
Authors: Marsden C.D. , Rothwell John C. 
Published: July 2016

ABSTRACT:Dystonia is mysterious and its pathophysiology is uncertain. The fundamental motor abnormality is an abnormality of muscle command signals, such that the wrong agonists may be activated for too long, there is abnormal co-contraction of agonist and antagonists, and there is excessive and misdirected action of synergists and postural fixators. The result is action dystonia. In addition, muscle spasms may occur spontaneously. The peripheral motor apparatus, the corticomotoneurone pathway, and (as far as is known) the proprioceptive feedback machinery, are all intact in primary dystonia. However, a defect of interneuronal machinery has been identified in both the brainstem and spinal cord. In blepharospasm there is hyperexcitability of the lower brainstem interneurones responsible for the R2 component of the blink reflex. In the dystonic arm there is loss of the later phases of la reciprocal inhibition from extensors to flexors. Both deficits may be due to loss of normal basal ganglia inputs onto interneurones. The known sites of focal lesions that may cause symptomatic dystonia all impair basal ganglia output. However, whether such abnormal interneuronal function is sufficient to explain dystonia is not known. Among many unanswered questions are 1) are the cortical instructions for movement specified correctly, and 2) what is responsible for the spontaneous dystonic spasms?
The Computerized Tomographic Appearance of Angiographically Occult Arteriovenous Malformations of the Brain
Authors: Leblanc Richard , Ethier Roméo 
Published: July 2016

SUMMARYEight patients with a histologically proven angiographically occult arteriovenous malformation of the brain had plain and infused computed tomographic (CT) examinations. In five cases angiography revealed a hypovascular mass and in three cases the angiogram was normal. On CT examination a high density lesion (six cases) and ventricular asymmetry (five cases) were demonstrated. In three patients presenting with intracerebral hemorrhage, the high density appearance and ventricular compression were accounted for by the presence of hematoma. In three of five seizure patients the high density lesion was associated with calcification while ipsilateral (one case) and contralateral (one case) enlargement of the lateral ventricle was seen. In five of the eight cases the vascular nature of the lesion was suggested by vascular enhancement of the infused CT scan. Glioma was a common misdiagnosis.
Friedreich’s Ataxia With Nephrotic Syndrome and Convulsive Disorder: Clinical and Neurophysiological Studies With Renal and Nerve Biopsies and An Autopsy
Authors: Watters G.V. , Zlotkin S.H. , Kaplan B.S. , Humphreys P. , Drummond K.N. 
Published: July 2016

SUMMARYIn a sibship of four, Friedreich’s ataxia and minimal lesion nephrotic syndrome occurred in two siblings, a third sibling had Friedreich’s ataxia, but no evidence of nephrotic syndrome; the fourth sibling had neither condition. The chance of Friedreich’s ataxia and minimal lesion nephrotic syndrome occurring in two siblings is small, and suggested a common immunological abnormality. High dose prednisone and antimetabolites given for the nephrotic syndrome did not appear to affect the course of Friedreich’s ataxia.The two siblings with Friedreich’s ataxia and nephrotic syndrome developed epilepsy at age 15 years. All three children with Friedreich’s ataxia had abnormal electroencephalograms (EEGs). These epileptiform EEG abnormalities were probably inherited from the mother, who had spike wave epilepsy. The neurologic deficits of Friedreich’s ataxia, in turn, may have allowed the EEG trait to be expressed as a seizure disorder. The progressive ataxia and epileptic, sometimes myoclonic, seizures in these patients and the dentate nucleus changes in the autopsied patient were consistent with the diagnosis of dyssynergia cerebellaris myoclonica. This suggested that the latter disorder may represent a coincidence of two genetic entities: Friedreich’s ataxia and spike wave epilepsy.
The Crossed Adductor Reflex in Humans: An EMG Study
Authors: Teasdall Robert D. , Den Ende H. Van 
Published: July 2016

SUMMARYCrossed adductor reflexes were recorded electromyographically in ten patients with bilateral lesions of the upper motor neuron. Three of these had a femoral neuropathy. Following blows directed to either the tendon of the adductor muscle or to the medial epicondyle of the femur, large amplitude responses of short latency were recorded from the ipsilateral adductor muscle while small amplitude responses of short latency and large amplitude responses of long latency were recorded from the contralateral adductor. The responses of short latency which were recorded from the ipsilateral and contralateral adductor muscles ranged from 18 to 27 ms. The contralateral responses of long latency ranged from 60 to 67 ms. On tapping the patella or patellar tendon, large amplitude responses of short latency were recorded from the contralateral adductor muscles while the ipsilateral adductor responses were absent. These responses resulted from stretch of the ipsilateral and contralateral adductor muscles. The contralateral responses were mediated across the midline by an extraspinal mechanical pathway.
Spinal Subdural Hematoma in Association with Anticoagulant Therapy
Authors: Russell Neville , Maroun F.B. , Jacob J.C. 
Published: July 2016

SUMMARYA case of spinal subdural hematoma occurring in association with anticoagulant therapy is reported. Seven similar cases from the literature are reviewed with emphasis on the clinical features, investigation, and the results of treatment. The prognosis for recovery is good, only if the condition is diagnosed and the clot evacuated before severe spinal cord compression and subsequent ischemic necrosis has occurred.
Positional Vertigo and Nystagmus of Central Origin
Authors: Watson P. , Barber H.O. , Deck J. , Terbrugge K. 
Published: July 2016

SUMMARY:Four cases are described illustrating the clinical features of positional vertigo and nystagmus due to posterior fossa tumors and a case of obstructive hydrocephalus. In these cases positional vertigo was the first and only presenting symptom of central nervous system disease. One case of subependymoma of the fourth ventricle and one with hydrocephalus had characteristic symptoms of benign positional vertigo; each showed positional nystagmus of the benign paroxysmal type.
Cerebrovascular Permeability in Mechanically Induced Hypertension
Authors: Nag Sukriti , Robertson David M. , Dinsdale Henry B. 
Published: July 2016

SUMMARY:Our previous studies of cerebrovascular permeability in angiotensin-induced acute hypertension demonstrated that the principal mechanism resulting in increased permeability is enhanced pinositose. In order to exclude the possibility that the enhanced pinositose was a direct effect of exogenous angiotensin, cerebrovascular permeability alterations were studied in nonpharmacologically induced acute hypertension.Rats receiving horseradish peroxidase (HRP) intravenously, were sacrificed 2½ minutes after the onset of hypertension induced by placing a clip on the abdominal aorta. These animals showed the same pattern of permeability alterations as had been observed previously in animals with angiotensin-induced acute hypertension. Focal segments of penetrating arterioles in the temporal and parietal cortex showed increased permeability to HRP. Permeable vessels showed increased numbers of pinocytotic vesicles and the interendothelial junctions revealed no alterations. Enhanced pinocytosis appears to be the principal mechanism resulting in increased cerebrovascular permeability in this model as well suggesting that the alterations of cerebrovascular permeability observed previously in angio-tensin-induced acute hypertension occur due to the hypertensive state and are not a direct drug effect of exogenous angiotensin.
Effect of L-Tryptophan on Spasmodic Torticollis
Authors: Lal S. , Young S.N. , Kiely M.E. , Hoyte K. , Baxter D.W. , Sourkes T.L. 
Published: July 2016

SUMMARY:The effect of L-tryptophan, a precursor of serotonin, and placebo were studied in eight patients with spasmodic torticollis. L-Tryptophan (5gpo as a single dose) which increased free plasma tryptophan 20-53 fold improved only one out of six patients. Two out of three patients, including the subject who improved following an oral load of tryptophan, improved with L-tryptophan combined with nicotinamide, a tryptophan pyrrolase inhibitor, when administered for 1-3 weeks. However, the magnitude of clinical improvement was not impressive. Our findings suggest that impairment of serotonergic function is not a general finding in spasmodic torticollis though it may play a minor role in the manifestation of this movement disorder in some patients. The present study emphasizes some of the difficulties in evaluating therapeutic response, namely, the intrinsic variability of the disorder, the response to placébo in some subjects and the limitations of methods for measuring change.
Clinical Progression of Giant-Axonal Neuropathy over a Twelve Year Period
Authors: Dooley Joseph M. , Oshima Yasufumi , Becker Laurence E. , Murphy E. Gordon 
Published: July 2016

ABSTRACT:Giant-axonal neuropathy (GAN), a chronic peripheral neuropathy with associated Central Nervous System dysfunction and tight curly hair, is described in a 17-year-old girl. Biopsies of this girl’s muscle and nerve are characteristic of this condition. Her clinical course over a 12 year period characterizes a disease of a slowly progressive nature.
A Simple and Reproducible Experimental in Vivo Glioma Model
Authors: Auer R.N. , Maestro R.F. Del , Anderson R. 
Published: July 2016

SUMMARY:A simple and reproducible injection technique has been developed for inducing an in vivo experimental astrocytoma model in rats. Newborn rats were injected with a suspension of astrocytoma C-6 cells in doses ranging from 5 to 1 X 105cells. The optimum dose of tumor cells was found to be between 104and 105cells, with a consistent 100% take rate seen above 1 X 104injected cells. The injection of less than 104cells resulted in a decreased ability to induce tumors, and a prolonged survival. The pathology was consistent with that of a glioblastoma multiforme. The tumor showed a diffuse infiltrating border, necrosis, and pseudopalisading. Light microscopy revealed undifferentiated tumor cells while electron microscopy demonstrated rough endoplasmic reticulum, Golgi complexes, mitochondria, and the occasional cilium and centriole. The nature of the astrocytoma C-6 cell line, and the advantages, disadvantages and possible uses of the model are discussed.
The Somatosensory Evoked Potential
Authors: Eisen Andrew 
Published: July 2016

Three decades have elapsed since Dawson (1947) recorded the first somatosensory evoked potential (SEP). Simple superimposition of individual responses was possible because the patient had progressive myoclonic epilepsy. In this disease the SEP amplitude is much enhanced (Shibasaki et al, 1978; Kelly et al, 1981). Subsequently Dawson (1951, 1954) presented his averager to the Physiological Society, thereby initiating the present-day explosive growth of evoked potentials.SEPs are made up of components with varying latencies. The components are best identified by latency and polarity as recorded at the scalp (P = positive and N = negative). Nevertheless, the nomenclature of somatosensory evoked potentials can be extremely confusing, mainly because the same component can have a different polarity depending on the electrode montage used. Generally speaking (but this is not a firm rule), far-field (subcortical) potentials are positive in polarity when a non-cephalic reference is used, whereas these same components have a negative polarity when the reference is on the scalp. It is therefore useful to always indicate the recording montage being employed. In addition, use of absolute latencies in the terminology can cause confusion because they are dependent upon length and body height. For example, the brachial plexus component usually occurs at about 9 msec, but may extend to as long as 11 or more msec in a very tall individual. Subsequent components then become difficult to identify in relation to normal means.
The Effects of Intermittent Insulin Therapy on the Autonomic Neuropathy in the Streptozotocin Diabetic Rat
Authors: Monckton George , Pehowich Enid 
Published: July 2016

SUMMARY:An ultrastructural study of the dorsal sympathetic ganglia, chain, and myenteric plexus is described in the streptozotocin diabetic rat after intermittent insulin treatment. The observations described cover the first two weeks following induction of diabetes in which insulin was administered subcutaneously twice daily. Significant regenerative changes were seen with marked axonal sprouting noted at three days. Degenerative changes were seen to be less severe than those in untreated animals. It is concluded that the improvement in the neuropathic changes with insulin treatment supports a transient primary role of the streptozotocin in causing the neuropathy — but that the subsequent improvement seems to be related to the partial control of the diabetes.
A Six-Month Phosphatidylcholine Trial in Friedreich’s Ataxia
Authors: Filla A. , Campanella G. 
Published: July 2016

SUMMARY:In a six-month open pilot study, pure phosphatidylcholine was administered intravenously (2.5g daily for a month) and orally (5g daily for five months) to sixteen patients with Friedreich’s ataxia (FA) and seven patients with other inherited ataxias. Only the oral treatment achieved a mild but significant, 25% improvement, mainly of “central” symptoms in the FA patients at stage 2 of the illness, that is, still able to walk without support and to lead an independent life. However, the drug was ineffective in the more advanced cases. These results are discussed and compared with those obtained with lecithin by other authors.
Sodium Valproate in the Treatment of the Intractable Childhood Epileptic
Authors: Keene D.L. , Metrakos K. , Watters G.V. , Sherwin A. 
Published: July 2016

SUMMARY:Sixty-five children with seizure disorders, who had been treated with multiple anticonvulsants but were poorly controlled, were selected from the Montreal Children’s Hospital Convulsive Disorder Clinic and Neurology Service and were treated with sodium valproate (valproate). All types of seizure disorders were included in the group.Rapid oral absorption of the drug lead to peak plasma levels in one to three hours (later peaks occurring if administered after meals). A mean plasma half-life of 12.8 hours was calculated. Correlation between oral dose and plasma levels was poor. The side effects which occurred in this study were trivial. Drug interactions occurred with phenobarbital, diphenylhydantoin and clonazepam.Sixty percent of patients had a greater than 50% reduction in seizure frequency with sodium valproate, but the best response was in generalized absence seizures. Since all types of seizures responded to some degree, a trial of sodium valproate is warranted in intractable seizure disorders of childhood regardless of classification.
Orientation-Specific Visual Evoked Potential Deficits in Multiple Sclerosis
Authors: Coupland Stuart G. , Kirkham Trevor H. 
Published: July 2016

SUMMARY:Checkerboard pattern reversal visual evoked potentials (VEPs) have proved useful in the confirmation of optic nerve disease in patients with multiple sclerosis (MS). Recently, evidence of orientation-specific loss in contrast sensitivity and the presence of orientation-specific visual evoked potential (VEP) deficits in MS patients has been obtained using sinusoidal gratings as stimuli. This study reports the presence of orientation-specific VEP delay in MS using the conventional checkerboard pattern presented in two orientations: normally oriented (check condition) or diagonally oriented (diamond condition).Peak latency values of the N70 and P100 components of the VEP were statistically analyzed using appropriate ANOVA and nonparametric statistics. As a group MS patients showed significant VEP delays under check and diamond pattern conditions. However, individual subject analysis revealed that about 20% of the MS population show VEP delay to only one pattern orientation. It was shown that by including a diamond pattern condition the diagnostic yield of VEP delay in these clinically definite MS patients was increased 11% over that obtained with check stimulation alone.
Mechanisms of Brain Damage in Twins
Authors: Norman Margaret G. 
Published: July 2016

SUMMARY:The brains of 18 twins dying in the perinatal period showed a variety of lesions. Eleven had subependymal cell plate hemorrhage which had ruptured into the lateral ventricles in five. Five had periventricular damage. Three had anoxic neuronal damage. One acardiac monster had bilateral cerebral infarction. One pair had unequal sized brains, probably due to unequal intrauterine nutrition. Twins have a high perinatal mortality and morbidity; as well, intrauterine events may alter brain growth and development in each twin unequally, so they are an imperfect model to study the effect of genes and environment on intelligence.
Auditory Brainstem Response Abnormalities in Autistic Children
Authors: Taylor M.J. , Rosenblatt B. , Linschoten L. 
Published: July 2016

SUMMARY:In an attempt to clarify issues of brainstem dysfunction and hearing thresholds in autistic children, we studied the Auditory Brainstem Responses (ABRs) in 32 children who clearly fit within the criteria of autism established by the National Society for Autistic Children (1977). ABRs were recorded between Cz and ipsilateral ear in response to click stimuli. Interwave latencies and auditory threshold in each ear were determined. Of the 32 children, 11 had moderate hearing loss (8 bilaterally) and 3 had severe to profound hearing loss, all bilaterally. 8 of the 14 with hearing loss also had associated features (e.g., perinatal encephalopathy). The I-III andI-Vinterwave latencies were significantly longer in the autistic children compared to normal control children; the increased conduction times were found mainly in the early portion of the auditory brainstem pathway. These data confirm some earlier reports of ABR abnormalities in autistic children and are concordant with some theories of the etiological basis of autism. The high incidence of hearing loss in these children is significant and routine ABR testing is recommended.
The Role of Computed Cranial Tomography (CT) in Epilepsy
Authors: Guberman A. 
Published: July 2016

SUMMARY:To evaluate the usefulness of CT in detecting unexpected brain lesions in epileptics, scan results were analyzed in a consecutive series of 196 adult epileptics in whom there was no known etiology for their seizures nor any abnormality on neurological examination. Nineteen additional epileptics, selected on the basis of an unexpected positive CT were also included for analysis.In the consecutive series, the overall incidence of abnormal scans was 16% with the highest yield (44%) found in patients with partial elementary seizures. Partial seizures secondarily generalized were correlated with a significantly higher CT positivity than purely partial seizures. Patients with seizures for less than six months more frequently showed CT abnormalities than patients with a longer history.In 25 of 51 cases with abnormal scans a specific lesion amenable to therapy was detected, including 16 neoplasms and 5 arteriovenous malformations. Other lesions included generalized or focal atrophy, infarcts, calcified lesions of tuberous sclerosis, unexplained calcifications and focal low-density or enhancing lesions.