bluuebunny/crossref_metadata_2025 huggingface dataset:
Shock Compression Synthesis of Diamond
Authors: Sawaoka Akira B. , Takamatsu Masanobu , Akashi Tamotsu
Published: December 2004

Easily obtainable polycrystalline diamond would have many additional applications in industry. Of the synthesis techniques currently in use, shock compression is one of the most promising, crack formation being its major problem. The production of compacts from diamond powders (see Figure) is described and a technique introduced in which the exothermic chemical reaction of additives is used to control the temperature distribution in a compact and thus avoid cracks.

magnified image
Pyrazaboles: New room‐temperature columnar liquid crystals
Authors: Barberá Joaquím , Giménez Raquel , Serrano José Luis
Published: December 2004

A nove approach to mesomorphism is reported in which discotic pyrazole derivatives are formed by dimerization of half‐disk‐shaped promesogenic pyrazoles throught BH2 bridges. The figure show the texture of the Dhd mesophase exhibited by one of the resulting pyrazoboles. How the mesomorphism is affected by the number and position of peripheral chains is alos described.

magnified image
Permeation Properties of Liquid Crystal—polymer composite membranes
Authors: Blumstein Rita B. , Ratto Jo Ann
Published: December 2004

The transport properties of membranes containing liquid crystals (LCs) are discussed and several examples presented that illustrate the potential of such membranes with and without a specific transport component. The thermal response, i.e. the influence of the LC phase transition on the permeability, and the effect of electric fields are described. It is shown that members of this unique family of membranes display the high flux characteristic of fluids above the mesophase transition temperature while retaining excellent mechanical properties.
Toward organic synthesis of a nanometer‐size magnetic particle
Authors: Rajca Andrzej
Published: December 2004

Magnetic phenomena in small magnetic particles include giant magnetoresistance and mesoscopic tunneling of quantum magnetization. Further progress in this area requires the availability of particles of uniform size and shape. Recent developments in the synthesis of monodisperse organic particles are discussed, in particular in the area of dendritic molecules, which could lead to an extension of the applications of such particles, which presently range from magnetic memories to permanent magnets.
Synthesis and pyrolysis of liquid organometallic precursors for advanced Si‐Ti‐C‐N composites
Authors: Hapke Jörg , Ziegler Günter
Published: December 2004

Single‐source precursors for hybrid nano‐scaled SiC/Si3N4‐TiC/TiN compositesare reported. These precursors avoid the segregation of Ti and Si during pyrolysis and other probems associated with mixtures, blends, or slurries of precursors. They are liquids, oxygen‐free (important due to the detrimental effects of oxide phases on the properties of non‐oxide ceramics) and solvent‐free, and employ polysilazane starting materials.
Stereomutation in optically active regioregular polythiophenes
Authors: Bouman Michiel M. , Meijer E. W.
Published: December 2004

π‐conjugated polymers substituted with optically active side chains (see Figure) have been studied using circular dichroism, a powerful technique which reveals conformational changes. Thermochroism with a unique stereomutation (see this month's cover also) has been observed in regioregular chiral polythiophenes.

magnified image
The effects of DC electric currents on the in‐vitro calcification of bioactive silicon wafers
Authors: Canham Leigh T. , Newey Jon P. , Reeves Chris L. , Houlton Mike R. , Loni Armando , Simons Andrew J. , Cox Timothy I.
Published: December 2004

That silicon could become an important tissue‐compatible biomaterial is suggested by recent results. First observations are reported here of the significant effects that electrical bias has on the calcification process under simulated a cellular physiological conditions. Cathodic current flow through porous silicon is shown to accelerate the kinetics of calcium phosphate deposition. Reasons why formation is restricted to the cathodically biased region and why calcium phosphate is not formed within the silicon layer are discussed.
Biomimetic synthesis of cadmium sulfide‐ferritin nanocomposites
Authors: Wong Kim K. W. , Mann Stephen
Published: December 2004

The chemical construction of dispersed CdS nanoparticles within the polypeptide cage of apoferritin is demonstrated to be possible by a multistep synthetic route, as shown schematically in the Figure. Ferritin‐induced nucleation of CdS clusters (squares) is followed by reaction with excess sulfide to give CdS–ferritin. Such biocompatible nanoparticles might find uses as tunable photochemical agents for diagnosis, sensing, and drug delivery.

magnified image
Highly oriented thin films of a substituted oligo(para‐phenylenevinylene) on friction‐ transferred PTFE substrates
Authors: Gill Richard E. , Hadziioannou Georges , Lang Philippe , Garnier Francis , Wittmann Jean Claude
Published: December 2004

Highly oriented thin films of oligo(p‐phenylenevinylene)s, oligoPPVs, provide information about the structure of polyPPV and structure‐property relationships. It is shown that deposition of a substituted oligoPPV onto highly preoriented PTFE substrates leads to highly oriented thin films and that annealing produces a remarkable morphological change (see Figure and also the cover), an indication of epitaxial growth.

magnified image
Sequential gas‐phase formation of Al2O3 and SiO2 layers on aerosol‐made TiO2 Particles
Authors: Fotou George P. , Kodas Toivo T.
Published: December 2004

Barrier alumina‐silica bilayers coated on titania aerosol particles (see Figure) may allow titania pigment with improved properties to be manufactured—e.g., the coatings protect the particles from sunlight. A single‐step coating process is presented and coating pathways for silica and alumina proposed. The characterization of the particles is described and key parameters controlling the morphology of the coating layers discussed.

magnified image
Preserving a globular protein shape on glass slides: A self‐assembled monolayer approach
Authors: Yang Zhihno , Yu Hyuk
Published: December 2004

The manufacture of low‐cost, protein‐friendly, biocompatible materials is important for biomedical applications. A method is presented for making glass surfaces—on which the globular protein shape is often lost –benign to proteins by covalently grafting relatively short poly((ethylene glycol)) chains (functionalized with trimethylsilane, see Figure), which form a brush‐like self‐assembled monolayer.

magnified image
Materials science in Europe
Authors: Jeglitsch Franz
Published: December 2004

Topics of particular concern to materials scientists in Europe are briefly outlined by Professor Franz Jeglitsch, the President of the German Materials Society DGM. These include the fact that Europe invests significantly less of its gross national product in research than the USA of Japan, that Europe is less successful in converting scientific competence into new products or market share than its competitors, and recent trends in the number of students reading scientific and engineering disciplines. Ways of tackling these points, e.g., by public relations work, are suggested.
Facile approach to a chemisorbed thin film of functionalized polythiophene on a glass surface
Authors: Ng Siu‐Choon , Yu Wang‐Lin , Huan Alfred C. H.
Published: December 2004

A facile approach to chemisorbed thin films of functionalized polythiophene on a glass surface (see Figure) via treatment of modified glass surfaces with a solution of the polymer is reported. Evidence for the presence of a thin polymer film is presented and the morphology investigated by atomic force microscopy. The thin films synthesized in this manner are resistant to dissolution, even in boiling solvents.

magnified image
Critical behavior and the processing of nanoscale porous materials
Authors: von Behren Jens , Chimowitz Eldred H. , Fauchet Philippe M.
Published: December 2004

Non‐destructive drying of nanoscale porous materials is possible using supercritical fluids as drying agents. It is demonstrated that, for a successful outcome to the drying process. Maintaining supercritical conditions is of extreme importance, as illustrated by the Figure, which shows a porous silicon surface subcritically dried with CO2 – it is cracked and peeling. In contrast, the supercritically dried material remains homogeneous.

magnified image
Superior attachment of high‐quality hydrogen‐free amorphous diamond films to solid materials
Authors: Anttila Asko , Lappalainen Reijo , Tiainen Veli‐Matti , Hakovirta Marko
Published: December 2004

The attachment of high‐quality amorphous diamond (a‐D) coatings has been studied with respect to the hardness of the underlying layer. A novel intermediate‐layer technique is reported that enables thick a‐D coatings to be deposited successfully on all solids at room temperature. The Figure shows an a‐D film, on a 1.2 μm layer of Al, that has cracked but not delaminated after the silicon‐wafer substrate was bent.

magnified image
Cerebrospinal fluid norepinephrine reductions in man after degeneration and electrical stimulation of the caudate nucleus
Authors: Wood James H. , Ziegler Michael G. , Lake C. Raymond , Shoulson Ira , Brooks Benjamin R. , Van Buren John M.
Published: January 2005

Lumbar cerebrospinal fluid (CSF) norepinephrine concentrations determined by radioenzymatic assay in 9 patients with caudate atrophy associated with Huntington's disease were lower (p < 0.02) than those in 9 age‐ and sex‐matched control patients.

Preoperative lumbar CSF norepinephrine concentrations were determined in 5 patients undergoing stereotaxic thalamotomy. No significant alterations in prestimulation lumbar CSF norepinephrine levels were recorded 12 days after electrode installation and thalamic coagulation. Lumbar CSF norepinephrine concentrations were reduced (p < 0.03), however, 12 hours following intermittent selective electrical stimulation of the caudate nucleus.

These data suggest that noradrenergic pathways in man are (1) impaired in Huntington's disease and (2) inhibited by direct caudate stimulation.
Transient ischemic attacks with normal arteriograms: Serious or benign prognosis?
Authors: Toole James F. , Yuson Carlo P.
Published: January 2005

Of 226 patients with cerebral transient ischemic attacks (TIAs) evaluated with panarteriography, 16 had no demonstrable abnormalities in the aorto‐cervico‐cranial arterial tree. During a follow‐up period ranging from three to eight years, 8 of the 16 were asymptomatic; 4 developed strokes and 3 died, 2 of cerebral infarction and 1 of myocardial infarction. The surviving patient who had a cerebral infarct continues to have TIAs. There were 2 other deaths, 1 from myocardial infarction and the other accidental. Two other patients continue to have TIAs.
Alzheimer neurofibrillary change in subacute sclerosing panencephalitis
Authors: Mandybur T. I. , Nagpaul A. S. , Pappas Z. , Niklowitz W. J.
Published: January 2005

Abundant instances of Alzheimer neurofibrillary change (ANC) composed of tubules 200 nm wide and twisted into segments each 800 nm in length, indistinguishable from those of Alzheimer disease, were found in electron micrographs of the brain of a 15‐year‐old boy who died following subacute sclerosing panencephalitis (SSPE) of more than nine years' duration. The clinical picture was typical, CSF measles antibody titer was high, and there were characteristic electroencephalographic findings.
Nerve conduction studies in natural rubella
Authors: Cuetter Albert C. , John Joseph F.
Published: January 2005

Normal nerve conduction velocities and terminal latency values were obtained in 31 patients with natural rubella, many of whom complained of numbness, tingling, and other subjective sensory abnormalities. The observations suggest that true neuropathy may not occur in natural rubella.
A new myasthenic syndrome with end‐plate acetylcholinesterase deficiency, small nerve terminals, and reduced acetylcholine release
Authors: Engel Andrew G. , Lambert Edward H. , Gomez Manuel R.
Published: January 2005

A new myasthenic syndrome is described in a patient whose symptoms began soon after birth and included generalized weakness increased by exertion, easy fatigability, hyporeflexia, and refractoriness to anticholinesterase drugs. Electromyography showed a decremental response at all frequencies of stimulation and a repetitive response to single nerve stimulation. Miniature end‐plate potentials (mepps) were of normal amplitude but of decreased frequency. The mepp duration and half‐decay time were prolonged, and prostigmine was without any additional effect. The quantum content of the end‐plate potential was decreased due to a reduced store of quanta immediately available for release, but the probability of release was normal. Quantitative electron microscopy demonstrated a 3‐fold to 4‐fold decrease of nerve terminal size and reduced postsynaptic membrane density. The postsynaptic folds showed focal degeneration, and many were distended by labyrinthine membranous networks that communicated with the synaptic space. Degenerating nuclei were found in the junctional sarcoplasm. The ultrastructural localization of the acetylcholine receptor protein was normal. Acetylcholinesterase (AChE) was absent from the motor end‐plates by histochemical and electron cytochemical criteria. Biochemical studies indicated total absence of the end‐plate‐specific 16 S species of AChE and marked decrease in total muscle AChE. A congenital defect in the molecular assembly of AChE or in its attachment to the postsynaptic membrane might represent the basic abnormality and condition the morphological and physiological alterations.
Chronic ketosis and cerebral metabolism
Authors: Devivo Darryl C. , Leckie Mary P. , Ferrendelli James S. , McDougal David B.
Published: January 2005

The effects of chronic ketosis on cerebral metabolism were determined in adult rats maintained on a high ‐fat diet for approximately three weeks and compared to a control group of animals. The fat‐fed rats had statistically significantly lower blood glucose concentrations and higher blood β‐hydroxybutyrate and acetoacetate concentrations; higher brain concentrations of bound glucose, glucose 6‐phosphate, pyruvate, lactate, β‐hydroxybutyrate, citrate, α‐ketoglutarate, alanine, and adenosine triphosphate (ATP); lower brain concentration of fructose 1,6‐diphosphate, aspartate, adenosine diphosphate (ADP), creatine, cyclic nucleotides, succinyl coenzyme A (CoA), acid‐insoluble CoA, and total CoA; and similar brain concentrations of glucose, malate, calculated oxaloacetate, glutamate, glutamine, adenosine monophosphate, phosphocreatine, reduced CoA, acetyl CoA, sodium, potassium, chloride, and water content. The metabolite data in the chronically ketotic rats demonstrate an increase in the cerebral energy reserve and energy charge. These data also suggest negative modification of the enzymes phosphofructokinase, pyruvic dehydrogenase, and β‐ketoglutaric dehydrogenase; positive modification of glycogen synthase; and possible augmentation of the hexose transport system. There was no demonstrable difference in brain pH, water content, or electrolytes in the two groups of animals. We speculate that the increased brain ATP/ADP ratio is central to most, if not all, the observed metabolic perturbations and may account for the increased neuronal stability that accompanies chronic ketosis.
Intracranial arteriovenous malformations in childhood
Authors: Kelly John J. , Mellinger James F. , Sundt Thoralf M.
Published: January 2005

During the 13‐year period 1964 through 1976, 37 patients less than 20 years old with an intracranial, parenchymal arteriovenous fistula were seen at the Mayo Clinic. The most frequent mode of presentation was hemorrhage or seizure. Other than angiography, computed tomography with contrast enhancement was the most helpful diagnostic test. Surgery was restricted to patients with intraparenchymal hematomas, intractable seizures, or subarachnoid hemorrhage with accessible lesions and to 1 infant with a massive, symptomatic malformation. Surgery generally was tolerated well, with reversal of most acute focal neurological deficits related to hematomas. In the nonsurgical group, follow‐up revealed a fairly stable neurological status during the period of the study.
Effects of hypothermia on the human brainstem auditory response
Authors: Stockard James J. , Sharbrough Frank W. , Tinker John A.
Published: January 2005

Latency measurements between three potentials (waves I, III, and IV/V) of the human brainstem auditory response can allow early detection of certain posterior fossa lesions. The diagnostic use of these interwave latencies requires knowledge of what factors may prolong them in the absence of disease. Hypothermia appears to be one such factor–in 5 neurologically and audiometrically normal patients, mean esophageal temperatures as high as 34.5°C resulted in prolongations of central auditory conduction time. Interwave latency prolongations that were abnormal relative to an age‐matched normal population were seen at 32.1° ± 0.3°C in patients with both spontaneous and induced hypothermia, and these abnormalities disappeared after rewarming to normothermia. Hypothermia often accompanies intoxication and coma and should therefore be considered when brainstem auditory response abnormalities are being interpreted in these two clinical conditions.
Clinical evaluation of metrizamide for neuroradiology in children
Authors: Swick Herbert M. , Sty John R. , Haughton Victor M.
Published: January 2005

Metrizamide is a nonionic water‐soluble contrast medium for neuroradiological studies that is less irritating to the nervous system than other water‐soluble agents. Studies in adults have shown that metrizamide has advantages over currently available media, but experience with children has been limited.

Sixty‐two children have had myelography or ventriculography using metrizamide. The children ranged in age from 11 days to 22 years. Technically satisfactory studies were obtained in every patient. No major complications were encountered. Minor side‐effects included headache in 11 children (18%), mild nausea or vomiting in 16 children (26%), and fever in 4 children (6%). Seizures did not occur. One infant in the study subsequently died of unrelated problems; there was no evidence of arachnoiditis at postmortem examination. Metrizamide is a safe, effective contrast medium for neuroradiological use in children.
Possible biochemical basis of memory disorder in Alzheimer disease
Authors: Smith Christine M. , Swash Michael
Published: January 2005

Damage to the hippocampal formation, whether focal or diffuse, leads to severe impairment of short‐term memory. The most common presenting symptom of Alzheimer disease is loss of short‐term memory, and histologically the hippocampus is characteristically affected. Choline acetyltransferase, which is involved in the synthesis of acetylcholine, is depleted in the hippocampus in the disorder. Anticholinergic drugs administered to normal subjects can simulate some aspects of the memory defect seen in Alzheimer disease. It is postulated that damage to a cholinergic neuronal pathway running to or from the hippocampus underlies the memory disorder. This suggestion implies that it may be possible to improve memory in patients with Alzheimer disease by pharmacological means.
Radiation myelopathy in children
Authors: Sundaresan N. , Gutierrez F. A. , Larsen M. B.
Published: January 2005

Three children, 1 with medulloblastoma, 1 with anaplastic cerebellar tumor, and 1 with acute lymphocytic leukemia, received craniospinal irradiation with an estimated cord dose between 1,100 and 1,200 rets. All 3 patients after a latent period of seven to eight months developed subacute transverse myelopathy. The myelopathy was cervical in 2 patients and thoracic in 1. Spinal fluid examination showed high protein levels in 2 patients. Myelography demonstrated a swollen cord in 2 patients and normal appearance in 1. Autopsy in 1 patient disclosed a necrotizing myelopathy. The findings suggest that children tolerate less well than adults what previously have been considered safe doses of radiation to the spinal cord.
Predictive control of eye movements in parkinson disease
Authors: Flowers K. A. , Downing A. C.
Published: January 2005

Four parkinsonian patients who had shown evidence of an impairment of predictive manual control and 4 age‐matched normal subjects were tested for the predictive control of eye movements. Subjects tracked a target with their eyes as it moved in either irregular “noise” or regular (predictable) linear ramp or sine waveforms. Eye movements were monitored by electrooculograpy, and the overall tracking time lag for each condition was determined by cross‐correlation. Both normal and parkinsonian subjects showed prediction in eye tracking on the regular waveforms (zero time lag or anticipation of the target track), indicating that (1) the parkinsonian loss of predictive control in manual tasks is not due to defective control of eye movements, and (2) there may be separate predictor mechanisms in the brain for eyes and hands.
Unusual presentation of traumatic extracranial internal carotid artery aneurysm
Authors: Bradbury Peter Gavin , Lambert Colin Douglas
Published: January 2005

A young man presented with apparent transient ischemic attacks following a motorcycle accident in which he sustained minor injuries only. Computerized axial tomography demonstrated a small right frontal infarct, and angiography revealed an aneurysm of the right internal carotid artery in its extracranial course. This was thought to be traumatic in origin.
Experimental scrapie in mice: Ultrastructural observations
Authors: Baringer J. Richard , Prusiner Stanley B.
Published: January 2005

Scrapie, kuru, and Creutzfeldt‐Jakob disease are characterized by a similar spongiform pathology, prolonged incubation periods, and an agent with unique physical, chemical, and biological properties. Swiss mice were inoculated with the scrapie agent and sacrificed three to five months later for light and electron microscopy. At three months, small vacuoles were seen within the neuropil of the cerebral cortex and basal ganglia. By the fifth month these vacuoles had increased in number and size and were accompanied by moderate astrocytic proliferation. The brainstem, cerebellum, and spinal cord showed variable changes of much less intensity. Many dialted postsynaptic processes contained osmiophilic particles in random or crystalline arrays. The particles, measuring approximately 23 nm in diameter, appeared consistently in postsynaptic processes of brain from scrapie‐infected mice, were lacking in controls, and were of a size consistent with sedimentation and filtration data for the scrapie agent. Whether these particles represent the scrapie agent must await further studies.
Clinical studies of intrathecal autologous lymphocyte infusions in patients with malignant glioma: A toxicity study
Authors: Neuwelt Edward A. , Clark Kemp , Kirkpatrick Joel B. , Toben Howard
Published: January 2005

The feasibility and toxicity of intrathecal lymphoid cell infusions in patients with glioma were examined in this study. Blood rich in lymphoid cells was obtained using the Haemonetics Model 30 cell separator; the lymphoid cells extracted were further purified on Ficoll‐Hypaque gradients. Four patients received a total of eighteen autologous lymphoid cell infusions, with between 1 × 106 and 5 × 109 lymphoid cells being infused on each occasion. No toxicity was observed, but the CSF glucose declined in 2 patients. In 1 patient examined at autopsy the lymphoid cells appeared to have gained access to the tumor bed as well as to the rest of the subarachnoid space.
The pathophysiology of myotonia produced by aromatic carboxylic acids
Authors: Furman R. E. , Barchi R. L.
Published: January 2005

A series of nine related aromatic monocarboxylic acids (ACAs) previously shown to inhibit muscle membrane chloride conductance (GCl) selectively in the rat were studied for their ability to produce myotonia. All nine induced characteristic repetitive electrical activity and delayed relaxation in isolated muscle, although the concentrations required for this action varied widely. In each case, myotonia was observed at concentrations that correlated closely with previously determined half‐maximal concentrations for inhibition of GCl. Intracellular recordings from muscle made myotonic with ACA revealed prolonged latencies at rheobase, multiple driven spikes, and self‐sustaining repetitive activity similar to that previously reported in hereditary goat myotonia. Phase‐plane diagrams of membrane action potentials recorded after exposure to the most effective of these compounds suggested little effect on the voltage‐dependent sodium system. The changes seen could be duplicated by simple removal of chloride ion.

The expression of repetitive electrical activity in the presence of low membrane GCl depends on ambient temperature and on the concentration of calcium ion. Increasing temperature and decreasing Ca++ predispose toward myotonic activity; converse conditions inhibit myotonia. Myotonia induced by ACA is inhibited by concentrations of diphenylhydantoin that are clinically effective in controlling hereditary myotonia in humans.
Tissue carnitine in reye syndrome
Authors: Willner Joseph H. , Chutorian Abe M. , Dimauro Salvatore
Published: January 2005

Skeletal muscle carnitine palmityltransferase and muscle or liver carnitine content were determined in biopsies from children during and after attacks of Reye syndrome. No consistent abnormaility of enzyme or cofactor was found. Reye syndrome is biochemically distinct from the clinically similar syndrome of systemic carnitine deficiency.
Introduction of automated systems to evaluate touch‐pressure, vibration, and thermal cutaneous sensation in man
Authors: Dyck Peter James , Zimmerman I. R. , O' Brien Peter C. , Ness Anders , Caskey Patrick E. , Karnes Jeannine , Bushek Wilfred
Published: January 2005

Systems for automatic assessment of cutaneous touch‐pressure, vibratory, and thermal sensation have been developed. These systems use stimuli which are quantified and reproductible, a two‐alternative forced‐choice technique, and programmed steps to test, score, and report. If normal responses from series of healthy persons have been measured, percentile values specific for test, site, age, and sex can be determined. Abnormality, as in neurological disease, can then be defined as the response which has a value greater than that of the 95th (or other) percentile. These systems may be used to detect and validate abnormalities of sensation in neurological disease and in persons at risk from new medications or from industrial toxins, and to monitor worsening or improvement of sensation in follow‐up of a patient or in evaluation of therapeutic regimens.
The splanchnic autonomic outflow in shy‐drager syndrome and idiopathic orthostatic hypotension
Authors: Low Phillip A. , Thomas Juergen E. , Dyck Peter James
Published: January 2005

Since splanchnic outflow is important in the maintenance of postural normotension in man, we performed a quantitative analysis of preganglionic autonomic neuron cell bodies of the seventh thoracic spinal cord segment and their corresponding axons in 2 patients with Shy‐Drager syndrome (SDS) and 1 with idiopathic orthostatic hypotension (IOH) and compared these values to control data. The intermediolateral column (ILC) neuron cell body counts were reduced to 17% of control levels in SDS and 52% of control levels in IOH. The B fiber counts in the corresponding ventral spinal root were reduced to 21% and 41% in SDS and IOH, respectively. From the present study and our previous results of ILC counts with age, we infer that orthostatic hypotension does not develop until half or more of the preganglionic autonomic neurons have degenerated. An additional finding in SDS is that there is involvement beyond autonomic neurons.
Palatal myoclonus and denervation supersensitivity in the central nervous system
Authors: Matsuo Fumisuke , Ajax Ernest T.
Published: January 2005

We postulate that palatal myoclonus after infarction of the brainstem or cerebellum, or both, is the manifestation of denervatio supersensitivity secondary to lesions involving the dentatorubroolivary system. Two cases of our own and 31 from the English and French literature were analyzed in order to determine the delay between the occurrence of presumed anatomical lesions and the recognition of palatal myoclonus. The intervals varied from 2 to 49 months with the median between 10 and 11 months. The natural history of palatal myoclonus following brainstem infarction seemed consistent with the hypothesis.
Creutzfeldt‐Jakob disease: Patterns of worldwide occurrence and the significance of familial and sporadic clustering
Authors: Masters Colin L. , Harris Jonathan O. , Gajdusek D. Carleton , Gibbs Clarence J. , Bernoulli Christoph , Asher David M.
Published: January 2005

The worldwide epidemiology of Creutzfeldt‐Jakob disease (CJD) is presented from an analysis of 1,435 patients. In the United States, the average annual mortality rate is at least 0.26 deaths per million. Temporal‐spatial clustering of cases was not found in the United States, but reports from other countries indicate that such clustering does occur. Fifteen percent of the cases were of the familial type, suggesting a genetic susceptibility to infection.

Iatrogenic transmission by corneal transplantation and neurosurgical operations has occurred, and the possibility is raised that previous surgery or preexisting neurological disease may be associated with an increased risk of developing CJD. It remains to be determined whether the virus of CJD is maintained only by patient‐to‐patient transmission, has a zoonotic reservoir such as scrapie, or causes widespread latent infection of man that is occasionally activated.
Creutzfeldt‐Jakob disease in France: I. Retrospective study of the Paris area during the ten‐year period 1968–1977
Authors: Brown Paul , Cathala Françoise
Published: January 2005

A systematic search for cases of Creutzfeldt‐Jakob disease occurring in the ten‐year period 1968 through 1977 was conducted in the city of Paris and surrounding departments which comprise the greater Paris area. Fifty‐six cases were found among the total population of approximately 10 million inhabitants, with a maximum incidence of 1.1 cases per year per million people in the densely populated city of Paris and a progressively lower incidence in the less heavily populated suburban and rural areas of the region. There was no temporal or geographic clustering of disease. Attention is drawn to the often rapid onset and short duration of illness (nearly two‐thirds of the patients died within five months of onset) and the frequent early occurrence of symptoms such as asthenia, diaphoresis, and disturbances of sleep and appetite.
Sporadic distal myopathy with early adult onset
Authors: Miller Robert G. , Blank Nathan K. , Layzer Robert B.
Published: January 2005

With the exception of the large series of adult‐onset hereditary distal myopathy from Sweden, few cases of primary muscle disease with a definite distal predilection have been published. We report 3 sporadic cases of distal myopathy with the following features: (1) early adult onset (26 to 33 years); (2) slowly progressive weakness affecting first the distal leg muscles and later the arms; (3) marked elevation of creatine phosphokinase (more than 10 times the normal value); and (4) electromyographic and histological evidence of myopathy in distal muscles. The differential diagnosis is discussed and other reported cases are reviewed. The differences between hereditary cases reported by others and the sporadic cases reported here form the basis for a tentative subclassification of this syndrome.
Central somatosensory conduction time in comatose patients
Authors: Hume Ann L. , Cant B. R. , Shaw N. A.
Published: January 2005

Somatosensory conduction time between the dorsal column nuclei and the cerebral cortex may be measured following median nerve stimulation by recording evoked potentials from both scalp and neck. Central conduction times were significantly increased relative to normal (5.6 ± 0.5 msec) in 11 of 24 comatose patients. Results within 10 and 35 days of onset of coma were correlated with the final outcome. Conduction times were independent of serum phenobarbital (0 to 630 μmol per liter) and of central body temperature (35.0 to 38.5°C). Serial studies in coma demonstrated (1) short‐term increases during temporary metabolic disorders, and (2) sustained increases with gradual recovery over many months, particularly after head injury.
Thrombocytopenia associated with sodium valproate treatment
Authors: Neophytides Andreas N. , Nutt John G. , Lodish Jules R.
Published: January 2005

The administration of sodium valproate to 30 patients in daily doses of 1,200 to 3,000 mg was associated with a significant reduction of the platelet count. Thrombocytopenia without any concomitant bleeding abnormalities occurred in 10 of the patients. Platelet counts returned to baseline levels after withdrawal of the drug.
Horizontal pursuit defect nystagmus
Authors: Abel L. A. , Daroff R. B. , Dell'Osso L. F.
Published: January 2005

A teenage girl with a chronic large posterior fossa tumor had primary position right‐beating nystagmus with a constant‐velocity slow phase. Smooth pursuit was normal to the left but absent to the right. Vestibuloocular movements were present in both directions. The findings are analogous to downbeat and upbeat nystagmus, in which unidirectional pursuit palsies have been postulated as the pathogenic mechanism. This is the first reported case of a horizontal pursuit defect causing nystagmus.
Ontogeny of spontaneous blinking and of habituation of the blink reflex
Authors: Zametkin Alan J. , Stevens Janice R. , Pittman Richard
Published: January 2005

Habituation of the blink reflex to glabellar percussion was examined in 164 infants and children from ages 2 days to 18 years and in 18 adults aged 18 to 50 years. Spontaneous blink rates were measured in 269 children and 179 adults. The mean number of glabellar taps required for habituation of the blink reflex increased from 2.7 (SD 1.2) at 0 to 2 months of age to a peak of 13.3 (SD 5.6) at age 3 to 4, remained at more than 10 until age 6, after which a rapid decline occurred, reaching the adult level of 2 to 5 blinks to habituation at age 12 years. The mean rate of spontaneous blinking was less than 2 per minute in early infancy and increased steadily during childhood up to age 14 or 15. The inverse relationship of spontaneous blink rate and number of blink reflexes to habituation in early childhood and in disorders of dopamine transmission suggests that spontaneous blink rate and habituation of the blink reflex reflect maturation and integrity of dopaminergic circuits in the brain.
Single‐dose pharmacokinetics and anticonvulsant efficacy of primidone in mice
Authors: Leal K. W. , Rapport R. L. , Wilensky A. J. , Friel P. N.
Published: January 2005

The pharmacokinetics and efficacy of the anticonvulsant primidone (PRM) and its active metabolites, phenobarbital (PB) and phenylethylmalonamide (PEMA), were studied after single‐dose administration in mice. The half‐life of PB is twice that of PRM and PEMA. The plasma/brain ratios provide evidence of poor penetration of PRM into brain. The results support our findings of negligible or absent PRM concentrations in the brains of patients on primidone therapy who were undergoing surgery for intractable epilepsy.

The anticonvulsant properties of PRM, PB, and PEMA against maximal electroshock in mice were also studied with the use of the metabolic inhibitor SKF 525A. The half‐life, potency, peak anticonvulsant effect, and effective dose curves of these compounds indicate that the anticonvulsant effect of short‐term oral PRM administration in mice is from derived PB.
Alexia, without agraphia, due to brain tumor: A reversible syndrome
Authors: Turgman Jacob , Goldhammer Y. , Braham J.
Published: January 2005

Alexia without agraphia occurred in a 41‐year‐old man suffering from a left occipital brain tumor. The syndrome disappeared following excision of the neoplasm.
Effects of reserpine, propranolol, and aminophylline on seizure activity and CNS cyclic nucleotides
Authors: Gross Robert A. , Ferrendelli James A.
Published: January 2005

Convulsant doses of pentylenetetrazol (100 mg/kg) increase levels of both cyclic adenosine monophosphate (AMP) and cyclic guanosine monophosphate (GMP) in mouse cerebral cortex and hippocampus. In animals pretreated with reserpine, propranolol, or aminophylline, pentylenetetrazol seizures were more severe, cyclic AMP elevations were attenuated or blocked, and cyclic GMP increases were unaffected or augmented. These data indicate that norepinephrine, adenosine, and perhaps other biogenic amines have a regulatory effect on cyclic AMP, but not cyclic GMP, levels in epileptic brain. An increased levels of cyclic AMP in brain tissue may have an antiepileptic effect leading to seizure attenuation or termination. By contrast, elevated levels of cyclic GMP may have an antiepileptic effect leading to seizure attenuation or termination. By contrast, elevated levels of cyclic GMP may have an epileptogenic effect in initiating or maintaining seizure activity.
Perisulcal infarcts: Lesions caused by hypotension during increased intracranial pressure
Authors: Janzer R. C. , Friede R. L.
Published: January 2005

A pattern of cortical necrosis surrounding the cerebral sulci and similar to ulegyria was found in 5 patients. The lesions were widely disseminated in all parts of the hemispheric cortex, affecting mostly the deep cortex of several adjacent sulci. They were hemorrhagic in 3 patients, ischemic in the others. Each patient had suffered a severe brain injury and became comatose thereafter. Increased intracranial pressure was evident from clinical findings, necropsy changes, or both. While in coma, each patient had at least one episode of hypotension. The data suggest that perisulcal infarcts are a manifestation of diminished vascular perfusion during a period of increased intracranial pressure.
Clinical pharmacology of mephenytoin and ethotoin
Authors: Troupin Allan S. , Friel Patrick , Lovely Mary Pat , Wilensky Alan J.
Published: January 2005

Effective prescribing of anticonvulsants requires foreknowledge of baseline pharmacokinetic data. Little such information is available about the hydantoins other than phenytoin, although one of them, mephenytoin, is widely used. Useful pharmacokinetic data should be derived from patients already exposed to anticonvulsants to reflect the induction of hepatic oxidative enzymes. Single‐dose studies of mephenytoin (Mesantoin) and ethotoin (Peganone) were performed in adult inpatients on stable regimens of other anticonvulsants. Five patients received mephenytion, 7 mg per kilogram of body weight. Serial blood sampling was performed rigorously. The time to peak concentration (Tmax) for mephenytoin was 1 hour, with a half‐life (T1/2) of 7 hours; the T1/2 of its metabolite, 5‐ethyl‐5‐phenylhydantion, was 96 hours. Ethotoin administration was 25 mg per kilogram in 5 patients. Ethotoin Tmax was 2 hours, with a T1/2 of 5 hours. Saliva accurately represented the unbound fraction for all three agents. Mean salivary levels (as percentage of total levels) were 61% for mephenytoin, 73% for its metabolite, and 54% for ethotoin.

The implication for therapy are that following mephenytoin administration, the metabolite 5‐ethyl‐5‐phenylhydantoin will provide anticonvulsant effectiveness, with its long half‐life producing stable blood levels on simple dose schedules. Ethotoin, in contrast, has a short half‐life and would require divided daily doses to achieve a steady state. This, rather than pharmacological ineffectiveness, limits its usefulness.
Alzheimer neurofibrillary tangles: Antiserum and immunohistological staining
Authors: Grundke‐Iqbal Inge , Johnson Anne B. , Terry Robert D. , Wisniewski Henryk M. , Iqbal Khalid
Published: January 2005

A 50,000‐dalton polypeptide has been purified from fractions enriched with neurofibrillary tangles of paired helical filaments from human autopsy specimens of Alzheimer disease and senile dementia of the Alzheimer type. An antiserum to this polypeptide was raised in a rabbit. This antiserum formed an immunoprecipition line with the purified antigen and with human neurotubules in Ouchterlong double‐diffusion plates. The reactivity of the anti‐paired helical filament protein serum with neurofibrillary tangles was studied by immunof uorescence on cryostat sections of hippocampus from Alzheimer autopsy tissue and by the peroxidase‐antiperoxidase technique on paraffin sections of an Alzheimer brain biopsy. The tangles were stained with the antiserum in both systems. Preimmune rabbit serum and unrelated hyperimmune sera, used as controls, did not stain the tangles. These results show that the 50,000‐dalton polypeptide purified form the neurofibrillary tangle‐enriched fractions is a constituent of Alzheimer neurofibrillary tangles and, perhaps, of the paired helical filaments of which the tangles are composed.
Central cholinergic activity in aluminum‐induced neurofibrillary degeneration
Authors: Hetnarski Bogumil , Wisniewski Henryk M. , Iqbal Khalid , Dziedzic John D. , Lajtha Abel
Published: January 2005

Choline acetyltransferase (CAT) and acetylcholinesterase (AChE) activities were measured in spinal cord homogenates from rabbits with aluminum‐induced neurofibrillary degeneration and a group of salinetreated, age‐matched controls. All Aluminum ‐treated animals showed neurofibrillary changes in the spinal cord, but CAT and AChE activities were not significantly different from levels in control animals. These results are at variance with the greatly reduced activity of these enzymes observed in Alzheimer disease and senile dementia of the Alzheimer type.
Treatment of myoclonus with l‐5‐hydroxytryptophan and carbidopa: Clinical, electrophusiological, and biochemical observations
Authors: Thal Leon J. , Sharpless Nansie S. , Wolfson Leslie , Katzman Robert
Published: January 2005

Six patients with myoclonus of varying cause were treated with L‐5‐hydroxytryptophan (L‐5‐HTP) and carbidopa. While spontaneous myoclonus decreased in three of the patients and action myoclonus in four, only two patients had marked functional improvement. Side effects included gastrointestinal and affective disturbances. L‐5‐HTP therapy caused a diminished frequency of paroxysmal discharges in the electroencephalograms of three patients which did not always correlate with clinical improvement. Lumbar cerebrospinal fluid 5‐hydroxyindoleacetic acid (5‐HIAA) concentration after probenecid was decreased in all patients prior to therapy, but this reduction did not predict treatment response. Urinary excretion patterns for 5‐HTP, serotonin, and 5‐HIAA during treatment were similar in responders and nonresponders. It is concluded that while some patients with myoclonus do benefit from L‐5‐HTP therapy, biochemical and electrophysilogical tests are not useful predictors of treatment response, and the high incidence of side effects limits the usefulness of this therapy.
Barrier mechanisms for neurotransmitter monoamines and their precursors at the blood‐brain interface
Authors: Hardebo Jan Erik , Owman Christer
Published: January 2005

The integrity of the endothelial cell lining of the cerebrovascular bed constitutes a morphological blood‐brain barrier mechanism to neurotransmitter monoamines. Circulating monoamines are prevented from entering the brain primarily at the luminal membrane of the endothelial lining. The small percentage of amines that may pass this membrane is deaminated within the endothelial cells and pericytes of brain microvessels (capillaries, venules, and small veins) and, in the case of large parenchymal and pial vessels, in the smooth muscle layers, where Omethylation also takes place. In the choroid plexus a corresponding deamination and O‐methylation takes place in the epithelial cells. The presence of these enzymes constitutes a further, enzymatic, blood‐brain barrier in the brain vessels for these monoamines. The monoamine precursors L‐3,4‐dihydroxyphenylalanine (L‐dopa) and L‐5‐hydroxytryptophan readily pass from the luminal endothelial cell membrane but are trapped by another enzymatic barrier mechanism. Within the endothelial cells and pericytes of the microvasculature, these compounds are decarboxylated to their corresponding amines and then immediately deaminated. One clinical implication of these enzymatic barrier mechanisms is the use of decarboxylase and monoamine oxidase inhibitors as adjuncts to L‐dopa treatment of Parkinson disease; these substances facilitate the entry of L‐dopa into brain and thus increase the amount of dopamine available at receptor sites. A brief hypertensive or hypertonic stimulus can transiently open the blood‐brain barrier through an effect on endothelial cell linings. High circulating concentrations of monoamines can also open the morphological barrier, but probably only indirectly by inducing an acute rise in systemic blood pressure. Once the barrier is open, systemically administered monoamines enter the brain parenchyma, where they can induce pronounced changes in cerebral blood flow and metabolism.
Sodium valproate and bone marrow suppression
Authors: Smith F. R. , Boots M.
Published: January 2005

Bone marrow suppression developed in a patient while she was on a regimen of sodium valproate. In addition, she had high titers of platelet autoantibodies and a coagulopathy, both recognized complications of valproate therapy. It is postulated that this drug was also responsible for the marrow suppression.
Long‐term cerebral effects of small doses of X‐irradiation in childhood as manifested in adult visual evoked responses
Authors: Yaar I. , Ron E. , Modan M. , Peretz H. , Modan B.
Published: January 2005

In Israel between the years 1949 and 1960, approximately 20,000 children ranging from 1 to 15 years of age were irradiated for eradication of tinea capitis. Radiation to the cerebral hemispheres ranged up to 140 rads. Of those treated, now adults, 44 subjects were elected by stratified sampling for recording and analysis of visual evoked responses (VERs). A control group of 57 subjects similar in age and ethnic origin was chosen. Two occipital leads, a right and a left, were recorded by the international 10–20 system. Fifty responses to diffuse white‐flash stimulation were averaged in each case. The first 256 msec (data points) of each VER were reduced to 77 variables by repeated averaging over three adjacent data points; these variables were then analyzed by several statistical methods.

The analyses detected significant differences between the VER averages in study subjects compared with controls. These differences may reflect delayed, probably permanent functional damage to the central nervous system caused by small doses of x‐radiation (XR) to immature normal human brain. The left hemispheres appeared to be more involved, consistent with the fact that these children received, on the average, more XR to the left side of the brain, as was shown in simulated phantom models. This disparity is reflected in a greater degree of difference between the left VERs of the irradiated versus control group. The major differences between the VERs occurred in the first part of the secondary response and suggest possible subcortical involvement. The results strengthen previous evidence of potential hazards of XR in children.