Neuroelectric correlates of a neuropsychological model of word decoding and semantic processing in reading disabled children

The purpose of this study was to distinguish the characteristics and components of event related potentials (ERPs) correlated with word decoding and semantic processing in a subgroup of children with specific reading disabilities related to visual processing deficiencies. The results were compared with those obtained from a group of normal readers previously studied (Ostrosky et al. in press). Visual ERPs were recorded to four stimuli: three physically different but with the same semantic content: a frequently used noun written in capitals (COCHE), the same noun in handwriting, the pictorial representation of the noun (drawing), and a neutral stimulus consisting of a checkerboard. Four derivations were used: occipital (O1-O2) and parietal (P3-P4) with reference to linked mastoids. Data were analyzed using multivariate procedures. A Principal Component Analysis with Varimax rotation of the solution was applied. In the normal readers, we found some components in the occipital derivations which identified the words presented in different styles of handwriting and others which seemed to identify these words with the pictorial representation (and not with the neutral stimuli). The first "verbal" components were situated around the 156-256 ms latency range and the second "semantic" components were observed at over 380 ms. In the disabled readers, there was no "verbal" or "semantic" recognition grouping of these physically different stimuli. As opposed to the normal readers, interhemispheric responses were symmetrical. At the left parietal leads in the normal readers, the morphology of the verbal stimuli (capitals and handwriting) were very similar throughout the sweep and both were very different from the nonverbal stimuli. At 376 ms the four stimuli elicited a prominent negative peak in which the verbal stimuli elicited significantly higher amplitude than the nonverbal stimuli. In the disabled group, the morphologies of the four stimuli were very similar and no significant differences were observed. The results are discussed in accordance with a hypothetical model of the neural bases underlying reading. The model takes into account the complexity of the reading process and the various cognitive skills required for its adequate performance, and emphasizes a complex, dynamic interplay between occipital, parietal and temporal areas.     

The use of Teflon-embedded calcium sulphate: dysprosium thermoluminescent dosimeters for chest radiography

As part of a U.S. multi-regional pilot study conducted by the six Centers for Radiological Physics, 12-mm-diameter by 0.4-mm-thick CaSO4:Dy Teflon-embedded discs were evaluated and used to measure patient entrance exposure on 60 "average" patients at 12 clinical centers. The discs were found to have adequate sensitivity, reproducibility and linearity up to 69.7 microC kg-1 (270 mR). The minimum measurable exposure was estimated as 0.4 microC kg-1 (1.5 mR). All responses were corrected for energy dependence, which varied +/- 20% from 1.7 to 6.5 mm Al half-value layer. Patient entrance exposure values ranged from 1.3 to 28 microC kg-1 (5 to 110 mR), with a median value of 5.2 microC kg-1 (20 mR). This value agreed with exposure measurements made on the chest radiography equipment using an ionization chamber and a phantom which simulated an "average" patient, and with published Nationwide Evaluation of X-Ray Trends (NEXT) data for the same period.     

Self-consistent field-molecular orbital (SCF-MO) calculations and nuclear magnetic resonance measurements for fosfomycin and related compounds

In the present work, the mechanism of action of fosfomycin [(-)-(1R,2S)-(1,2-epoxypropyl)phosphonic acid] as an antibiotic agent is studied by "ab initio" quantum mechanical calculations and by 1H, 13C, and 31P NMR measurements. Attention is focused on the relative charge density and chemical shift of the C(2) atom of the epoxy ring, which seems to be closely related with the activity of this antibiotic. The theoretical results suggest that the sulfhydryl addition should be preceded by a necessary anchoring of the phosphonate moiety on a positive group of the receptor.     

Biopharmaceutical investigation of fenoprofen

The salts of fenoprofen formed with different metals have shown various crystal forms and solubility. The calcium salt has proved the most suitable characteristics for tablet and capsule production. Dissolution and absorption parameters of this substance were studied using in vitro and in vivo methods. The absorption rate and the correlation between pH and membrane diffusion rate constant were investigated in vitro using the "Sartorius" apparatus. The dissolution rate--depending on pH--was investigated by the oscillometric method. The in vivo disintegration of an experimental sample was compared with a commercial preparation. The comparison has been documented by endoscopic photography.     

Tricuspid atresia. Clinical course in 120 children

We describe the clinical course of 120 children with tricuspid atresia (TA) attended in the Hospital de Cardiología y Neumología, "Dr. Luis Méndez", del Centro Médico Nacional. There were 61 males and 59 females. The age of presentation was in 79 newborn babies, seventeen between one and six months old, 20 between six and 24 months old, and four with two or more years old. The clinical picture was hypoxic spells in 89% and congestive heart failure in the others. The chest film showed cardiomegaly in 85%, with diminished pulmonary flow in 48%, increased flow in 27.5%, and normal in 9%. The electrocardiogram with superior left axis deviation in 94%, right atrial hypertrophy in 58%, left atrial hypertrophy in 47.5% and left ventricular hypertrophy in 96%. TA was classified as type I in 103 children, type Ic in 70, Ib in 27 and Ia in six, and type II in seventeen children, with eight IIc, six IIb and three IIa. In 44 the management was medical, 63 underwent systemic-pulmonary anastomosis, 37 of them with Blalock-Taussig shunt and Fontan procedure in thirteen children. There were 21 deaths. This survey is compared with the literature and from this point we make management recommendations.     

A new case of arginase deficiency in a Spanish male

A new case of arginase deficiency is reported in a male newborn from Spain. In contrast with the majority of the earlier cases, this infant showed severe protein intolerance of early onset. The diagnosis was based on the assay of the urea cycle enzymes in a postmortem liver sample. Levels of erythrocyte arginase were also determined in the parents and in a sister of the patient, and were consistent with heterozygosity. From a study of the pedigree it appears that arginase deficiency in this family presents a dramatic course.     

Transplantation of Pacinian corpuscles of the rat into the brain

Summary In adult inbred rats of the AVN strain, branches of the crural interosseous nerve were dissected out from donors and transplanted into the brain of recipients, together with a cluster of Pacinian corpuscles, (either into a suction cavity or the cerebral cortex) into a slit 1–2 mm deep. The grafts were fixed and processed for electron microscopy 10 days to 6 months after the operation, and their ultrastructure was examined. Sporadic axons of small diameter grew into the nerve branches of some of the grafts from 11 days onward, and became myelinated during the 2nd month after the operation, but none of the transplanted Pacinian corpuscles became reinnervated. The corpuscles, however, survived denervation and grafting. Most of them retained a well-preserved inner core and an intact capsule, consisting of a normal complement of 29.2±1.0 (mean ±SE) capsular layers (n=8), as did the corpuscles previously examined after denervation in situ. Some of the corpuscles underwent degenerative changes, presumably due to a delayed or restricted revascularization. In this group of corpuscles, the inner core underwent disintegration and was gradually replaced by collagen fibrils, whereas the capsule remained preserved but the number of its layers eventually reduced by 40%. It is assumed that the lack of reinnervation of the grafted Pacinian corpuscles was due to the paucity of regenerating axons, and their failure to form correct projections along those Schwann cell columns connected with the corpuscles.     

Bilateral brain abscesses complicating the use of crutchfield tongs

The case of a 4-year-old girl who developed bilateral brain abscesses complicating skull traction is reported. Crutchfield tongs were used to reduce a fracture dislocation at C2–3. Presenting symptoms consisted of headaches and focal seizures. Surgical treatment and antibiotics using serial CT led to a satisfactory outcome. This is the first reported case of this complication in a child. The current literature is reviewed.To whom offprint requests should be addressed at Avda. Pio Baroja 4, 30011 Murcia, Spain     

Zur Beeinflussung des Knochengewebes durch mechanische Kräfte

Zusammenfassung An einigen Beispielen wird gezeigt, daß die mechanische Beeinflussung des Knochengewebes nicht so sehr von der Richtung äußerer einwirkender Kräfte abhängig ist als vielmehr von den aus diesen Kräften entstehenden Druckspannungen und deren Orientierung zu den vorhandenen, ausgebildeten Druckspannungsrichtungen (Trajektorien) des jeweiligen Knochens. Auswertungen, die sich nur auf Druck- und Zugwirkungen äußerer Kräfte beschränken, können nur unbefriedigende Antworten geben.

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Summary The effect of mechanical forces on bone depends not so much on the direction of the externally acting forces but more on the compressive strain originating on those forces and their orientation with respect to the existing trajectories of the respective bones. This fact is demonstrated by some examples. Analyses, based solely on pressure and tension effects of externally acting forces do not give satisfactory explanations.

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Résumé A l'aide de quelques examples, on démontre que l'influence mécanique sur le tissue osseux ne dépend pas tant de la direction des forces externes, mais plutôt des tensions compressives, produites par ces forces, et de leur orientation vers les directions formées par les tensions compressives (trajectoires) de l'os en question. Les appréciations, restreintes seulement aux effects de compression et de traction des forces externes, ne sont pas capables de donner des réponses satisfaisantes.