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Acute poisoning by selenious acid.

A 2 yo male child ingested approximately 15 ml of a Gun Blue solution containing selenious acid, nitric acid and copper nitrate. He was immediately given milk and vomited spontaneously blood-stained food with a garlic smell. He was admitted to our Centre less than 3 hr following ingestion. An esophago-gastroscopy showed a second degree burn of both esophagus and stomach. He became comatose and had to be ventilated mechanically. Metabolic acidosis, leucocytosis, hyperglycemia and hemoconcentration were also observed. During the following day he developed a severe intestinal distension, a cardiomyopathy (CPK = 1,302, cardiac arrhythmia), and moderate hepatic, renal and pulmonary dysfunctions. Plasma selenium concentration was 285 micrograms/L and the maximum urinary concentration was 28,459 micrograms/L. After 4 days, his condition had improved considerably and he was about to be extubated when he suddenly developed acute respiratory distress. A similar episode occurred 24 hr later. His lung function progressively deteriorated; later he required the use of an extracorporeal membrane lung. Legionella dumofii was found the causative agent. He died 17 d after ingestion despite aggressive treatment. Acute selenious acid poisoning and its relation to Legionnaire's disease is discussed.

Acid-Base Imbalance↗

[Laterality of tinnitus: relationship to functional assymetries].

Tinnitus is a sensation of sound generated by the auditory system due to pathology, without any external acoustic or electrical stimulation. Clinical reports have indicated that tinnitus affects the left ear more frequently than the right one. Previous data suggest that the asymmetrical distribution of tinnitus is linked to handedness or other lateral signs, but no studies have heretofore examined lateral preferences in addressing this relationship. The literature concerning the laterality (localisation) of tinnitus is reviewed. The data confirm an asymmetrical distribution of tinnitus. Results of 7 studies (altogether 4634 patients) demonstrate that tinnitus occurs more often bilaterally (48.8%) than on the left side (28.0%) or the right (23.2%). There is no general predominance of the left ear. Handedness, eyedness, footedness, earedness and dichotic listening are examined in our own sample of 58 patients (23 men and 35 women) with acute, subacute or chronic tinnitus. A right sided preference was found for hand, foot, eye, ear preference and dichotic listening among 91%, 86%, 78%, 69% and 85% of the sample, respectively. Sixty per cent of the sample heard tinnitus only in the left ear, 21% only in the right ear and 19% in both ears. There is a higher correlation between localisation of tinnitus and dichotic listening than between other lateralities. Our investigation shows a significant relationship between localisation of tinnitus and laterality of dichotic listening, suggesting a possible link between tinnitus and hemisphere dominance. The result suggests a "functional" asymmetry of tinnitus.

Acute Disease↗

[Development and perspectives of neuropsychology].

Neuropsychology is a new discipline placed between neurosciences (neurophysiology, neurochemistry, comparative neuroanatomy) and psychology (experimental psychology. psycholinguistics, linguistics). History of neuropsychology shows, during last and the beginning of the present centuries, a marked trend to localization and association (one center for each function, followed later by a period where globalistic trends predominate, according to which a localized lesion is important mostly because of the modification it produces in the functions of brain as a whole. During the last 30 years, the development of anatomoclinical methods and experimental neuropsychology have again given impulse to a neoassociational trend. By their importance, recent advances in the following topics are underlined: (1) The study of behaviour, particularly regarding the role of neurotransmitters. (2) The concept of "hemispheric specialization" in substitution of "hemispheric dominance". (3) The mechanisms of functional reestablishment in the central nervous system. (4) The role of genetic background and experience in the development of functions of the central nervous system.

Animals↗

Motor and nonmotor behavioral deficits in monkeys made hemiparkinsonian by intracarotid MPTP infusion.

We tested five monkeys (three Macaca mulatta, two Macaca nemistrina) made hemiparkinsonian by internal carotid artery infusion of 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) for lateralized motor function using a bar press task and a reaction time/movement time task and for hemispatial neglect or hemi-inattention using a double simultaneous stimulation (DSS) task, a lateralized reward retrieval task, and a task that assessed response to lateralized moving stimuli. All monkeys had impaired bar press performance and prolonged reaction and movement times with the limb contralateral to the lesion. However, using the limb ipsilateral to the lesion, all animals showed extinction to DSS, that is, they responded to single stimuli presented on the impaired side (contralateral to the MPTP lesion) more often than to stimuli presented on the impaired side that were presented simultaneously with stimuli on the unimpaired side (ipsilateral to the lesion). There was a response bias toward the side ipsilateral to the lesion in the lateralized retrieval task and a deficit in the ability to direct attention toward the side contralateral to the lesion when moving stimuli were employed. These latter results could not be explained by primary motor or sensory impairments. We conclude that unilateral MPTP-induced dopamine depletion in monkeys causes a complex syndrome characterized by overt motor disturbances contralateral to the side of lesion and less overtly apparent sensorimotor integration deficits.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

Electroencephalographic, volumetric, and neuropsychological indicators of seizure focus lateralization in temporal lobe epilepsy.

CONTEXT: Anterior temporal lobectomy is an effective treatment for medically intractable temporal lobe seizures. Identification of seizure focus is essential to surgical success. OBJECTIVE: To examine the usefulness of presurgical electroencephalography (EEG), magnetic resonance imaging (MRI), and neuropsychological data in the lateralization of seizure focus. DESIGN: Presurgical EEG, MRI, and neuropsychological data were entered, independently and in combination, as indicators of seizure focus lateralization in discriminant function analyses, yielding correct seizure lateralization rates for each set of indicators. SETTING: Comprehensive Epilepsy Program, Shands Teaching Hospital, University of Florida, Gainesville. PATIENTS: Forty-four right-handed adult patients who ultimately underwent successful anterior temporal lobectomy. Left-handed patients, those with less-than-optimal surgical outcome, and any patients with a history of neurological insult unrelated to seizure disorder were excluded from this study. MAIN OUTCOME MEASURES: For each patient presurgical EEG was represented as a seizure lateralization index reflecting the numbers of seizures originating in the left hemisphere, right hemisphere, and those unable to be lateralized. Magnetic resonance imaging data were represented as left-right difference in hippocampal volume. Neuropsychological data consisted of mean scores in each of 5 cognitive domains. RESULTS: The EEG was a better indicator of lateralization (89% correct) than MRI (86%), although not significantly. The EEG and MRI were significantly superior to neuropsychological data (66%) (P=.02 and .04, respectively). Combining EEG and MRI yielded a significantly higher lateralization rate (93%) than EEG alone (P<.01). Adding neuropsychological data improved this slightly (95%). CONCLUSIONS: The EEG and MRI were of high lateralization value, while neuropsychological data were of limited use in this regard. Combining EEG, MRI, and neuropsychological improved focus lateralization relative to using these data independently.

Adult↗

Is there a sex difference in human laterality? III. An exhaustive survey of tactile laterality studies from six neuropsychology journals.

The contents of six neuropsychology journals (161 volumes, 612 issues) were screened to identify tactile laterality experiments. Of 73 experiments identified, 40% provided information about sex differences. Seventeen experiments yielded a total of 18 sex differences, of which 4 could be interpreted in terms of the hypothesis that functional cerebral lateralization is more pronounced in males. All 4 interpretable outcomes (constituting 5.5% of the population of experiments and 13.8% of the informative experiments) were found to be consistent with the differential lateralization hypothesis. The results, in isolation, do not justify rejecting the null hypothesis. However, when considered in conjunction with findings for auditory and visual laterality studies, the present results are compatible with a weak population-level sex difference.

Adult↗

Perinatal gonadectomy exerts regionally selective, lateralized effects on the density of axons immunoreactive for tyrosine hydroxylase in the cerebral cortex of adult male rats.

The catecholamine innervation of the cerebral cortex is essential for its normal operations and is implicated in cortical dysfunction in mental illness. Previous studies in rats have shown that the maturational tempo of these afferents is highly responsive to changes in gonadal hormones. The present findings show that perinatal hormone manipulation also has striking, region- and hemisphere-specific consequences for cortical catecholamines in adulthood. The effect of perinatal gonadectomy on catecholamines was examined in representative sensory, motor, and association cortices of adult male rats by combining hormone manipulation with immunocytochemistry for tyrosine hydroxylase, a rate-limiting enzyme in catecholamine biosynthesis. Qualitative and quantitative comparison of immunoreactivity in rats perinatally gonadectomized or sham-operated revealed complex changes in gonadectomized subjects; in cingulate cortex, TH immunoreactivity was strongly and bilaterally diminished, in sensory and motor cortices, axon density was decreased in left hemispheres, but was minimally affected on the right, and in a premotor cortex, gonadectomy was without significant effect in either hemisphere. Corresponding analyses in gonadectomized rats supplemented with testosterone revealed a protective influence, albeit one in which TH immunoreactivity so showed regional and hemispheric variability in responsiveness to hormone replacement. These complex patterns of TH sensitivity suggest highly asymmetric hormone stimulation of cortical catecholamines. Such discriminative action may contribute to sex differences in the functional maturation and lateralization of the cortex and may also have bearing on disorders such as dyslexia, which show sexual dimorphisms, and in which functional laterality of the cortex may be particularly at issue.

Animals↗

Anatomical specialization of the anterior motor speech area: hemispheric differences in magnopyramidal neurons.

The lateralization of motor speech function to the left hemisphere is supported by multiple lines of evidence, but relatively little is known about the anatomical basis of that specialization. In a preliminary study, we recently reported that area 45 of the left hemisphere (Broca's area) contained a subpopulation of magnopyramidal neurons which were significantly larger than any seen in the homotopic region of the right hemisphere (Hayes & Lewis, 1993a). In the present study we examined a larger sample of cases in order to determine how consistently this difference is present in the population, if it is specific to Broca's area or is a general feature of cortical regions mediating lateralized functions, and whether the subpopulation of large magnopyramidal neurons in left area 45 can be distinguished by their chemical phenotype. In Nissl-stained sections from 19 human brains, the mean (+/- SD) cross-sectional area of the largest layer III pyramidal neurons in area 45 was significantly (p < .0001) greater in the left hemisphere (522.1 +/- 128.3 microns2) than in the right (454.1 +/- 121.5 microns2). This interhemispheric difference appeared to be a unique characteristic of the largest neurons, since the mean size of all layer III pyramids in this area was not significantly different in the left (206.2 +/- 93.5 microns2) and right (213.3 +/- 103.9 microns2) hemispheres. In contrast to area 45, there was no interhemispheric difference in the mean cross-sectional area of the largest layer III pyramids in another lateralized region, primary motor cortex. In addition, in area 46, a region of prefrontal association cortex not known to be functionally lateralized, the mean somal size of the largest layer III pyramidal neurons was significantly (p < .001) smaller in the left hemisphere (402.4 +/- 84.9 microns2) than in the right (437.8 +/- 88.3 microns2). Finally, although the large layer III pyramids in area 45 were immunoreactive for nonphosphorylated neurofilament protein in both hemispheres, the mean cross-sectional area of the largest labeled neurons was significantly larger (p < .002) in the left hemisphere (525.2 +/- 149.0 microns2) than in the right (490.3 +/- 154.1 microns2). These findings demonstrate that layer III of Broca's area contains a distinctive subpopulation of neurons that may play an important role in the specific functional architecture of this region.

Adult↗

Multiple measures of hemispheric dysfunction in schizophrenia and depression.

Electrodermal, electroencephalographic and perceptual measures of lateral hemispheric function were obtained from groups of chronic schizophrenics, depressives and normals on 2 occasions, separated by 4 weeks. The measures of hemispheric function were derived from previous research. About half of the schizophrenics were medicated on both occasions; the other schizophrenics underwent drug 'washout' before the first session. Results revealed that the measures of laterality were not strongly intercorrelated. In the perceptual task, the schizophrenics and normals displayed different laterality effects. Unlike the normals, the schizophrenics' left hemisphere function appeared to be inferior to the right hemisphere function in the perceptual task. The laterality effects of the depressives and normals differed on two electrodermal measures: skin conductance level and skin conductance response amplitude. The depressives' electrodermal activity from the right hand was diminished as compared with the left hand; the normals did not show this effect. Medication decreased electrodermal activity in the schizophrenics, but had no significant effect on laterality. These results suggest that the various measures of laterality used singly in previous research in psychopathology may not all assess the same phenomenon.

Adolescent↗

Different functional treatment strategies for acute lateral ankle ligament injuries in adults.

BACKGROUND: Acute lateral ankle ligament ruptures are common problems in present health care. Early mobilisation and functional treatment are advocated as a preferable treatment strategy. However, functional treatment comprises a broad spectrum of treatment strategies and as of yet no optimal strategy has been identified. OBJECTIVES: The objective of this review is to assess different functional treatment strategies for acute lateral ankle ligament ruptures in adults. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group specialised register (December 2001), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 4, 2001), MEDLINE (1966 to May 2000), EMBASE (1980 to May 2000), CURRENT CONTENTS (1993 to 1999), BIOSIS (to 1999), reference lists of articles, and contacted organisations and researchers in the field. SELECTION CRITERIA: Randomised clinical trials describing skeletally mature individuals with an acute lateral ankle ligament rupture and comparing different functional treatment strategies were evaluated for inclusion. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the quality of included trials and extracted relevant data on treatment outcome. Where appropriate, results of comparable studies were pooled. Individual and pooled statistics are reported as relative risks (RR) for dichotomous outcome and (weighted) mean differences (WMD) for continuous outcome measures with 95 per cent confidence intervals (95%CI). Heterogeneity between trials was tested using a standard chi-squared test. MAIN RESULTS: Nine trials involving 892 participants were included. Lace-up ankle support had significantly better results for persistent swelling at short-term follow up when compared with semi-rigid ankle support (RR 4.19, 95% CI 1.26 to 13.98); elastic bandage (RR 5.48; 95% CI 1.69 to 17.76); and to tape (RR 4.07, 95% CI 1.21 to 13.68). Use of a semi-rigid ankle support resulted in a significantly shorter time to return to work when compared with an elastic bandage (WMD (days) 4.24; 95% CI 2.42 to 6.06); one trial found the use of a semi-rigid ankle support saw a significantly quicker return to sport compared with elastic bandage (RR 9.60; 95% CI 6.34 to 12.86) and another trial found fewer patients reported instability at short-term follow-up when treated with a semi-rigid support than with an elastic bandage (RR 8.00; 95% CI 1.03 to 62.07). Tape treatment resulted in significantly more complications, the majority being skin irritations, when compared with treatment with an elastic bandage (RR 0.11; 95% CI 0.01 to 0.86). No other results showed statistically significant differences. REVIEWER'S CONCLUSIONS: The use of an elastic bandage has fewer complications than taping but appears to be associated with a slower return to work and sport, and more reported instability than a semi-rigid ankle support. Lace-up ankle support appears to be effective in reducing swelling in the short-term compared with semi-rigid ankle support, elastic bandage and tape. However, definitive conclusions are hampered by the variety of treatments used, and the inconsistency of reported follow-up times. The most effective treatment, both clinically and in costs, is unclear from currently available randomised trials.

Adult↗

Predictive value of the intracarotid amobarbital test in bihemispheric seizure onset.

The intracarotid amobarbital test (IAT) is used to lateralize language function and assess hemispheric memory. In this study 23 non-lesional epileptic patients were evaluated. The magnitude of the difference in IAT scores between the two hemispheres was significantly greater in the patients whose seizures lateralized on scalp or intracranial EEG than in patients with bihemispheric seizure onset. This suggests that the IAT is useful not only in predicting lateralized seizure focus, but bihemispheric onset as well.

Adult↗

Lateralization of language and spatial functions in left-handed populations.

The level of performance in the execution of a tactual-linguistic task was studied in two left-handed populations, one with language lateralized to the left and the other with language lateralized to the right hemisphere, according to Kimura's dichotic digit test. The results showed that left-handers with speech most likely lateralized to the left hemisphere performed significantly better in the tactual-linguistic task with the left hand, while the ones with speech probably lateralized to the right hemisphere, did better with the right hand. The data suggest that integration of functions asymmetrically represented is facilitated by their differential lateralization.

Adolescent↗

Functional anatomy of the lateral collateral ligament complex of the elbow: configuration of Y and its role.

A previous anatomic study has revealed that the lateral collateral ligament (LCL) complex of the elbow has a Y-shaped configuration, which consists of a superior, an anterior, and a posterior band. The LCL complex, including the annular ligament, functions as a 3-dimensional (3D) Y-shaped structure. On the basis of this concept, joint laxity after transection of the anterior band was studied in 5 normal, fresh-frozen cadaver elbows with a 3D kinematic testing apparatus. Cutting the anterior band produced significant laxity to varus torque with a mean 5.9 degree at 10 degree of elbow flexion and caused significant laxity to torque in external rotation with a mean 8.5 degree at 40 degree of flexion. No significant laxity was observed during application of valgus or internal rotational torque. Further transection of the posterior band resulted in gross instability with dislocation of the ulnohumeral joint. The laxity occurring after severance of the anterior band suggests that these fibers play a role in preservation of elbow stability against varus and external rotational torque. These results indicate that the LCL functions as a complex with a Y structure and not as an isolated linear ligament. A concept of conjoint point is hypothesized for the function of the LCL complex to restrain posterolateral rotatory instability.

Aged↗

A cochlear frequency-position function for several species--29 years later.

Accurate cochlear frequency-position functions based on physiological data would facilitate the interpretation of physiological and psychoacoustic data within and across species. Such functions might aid in developing cochlear models, and cochlear coordinates could provide potentially useful spectral transforms of speech and other acoustic signals. In 1961, an almost-exponential function was developed (Greenwood, 1961b, 1974) by integrating an exponential function fitted to a subset of frequency resolution-integration estimates (critical bandwidths). The resulting frequency-position function was found to fit cochlear observations on human cadaver ears quite well and, with changes of constants, those on elephant, cow, guinea pig, rat, mouse, and chicken (Békésy, 1960), as well as in vivo (behavioral-anatomical) data on cats (Schucknecht, 1953). Since 1961, new mechanical and other physiological data have appeared on the human, cat, guinea pig, chinchilla, monkey, and gerbil. It is shown here that the newer extended data on human cadaver ears and from living animal preparations are quite well fit by the same basic function. The function essentially requires only empirical adjustment of a single parameter to set an upper frequency limit, while a "slope" parameter can be left constant if cochlear partition length is normalized to 1 or scaled if distance is specified in physical units. Constancy of slope and form in dead and living ears and across species increases the probability that the function fitting human cadaver data may apply as well to the living human ear. This prospect increases the function's value in plotting auditory data and in modeling concerned with speech and other bioacoustic signals, since it fits the available physiological data well and, consequently (if those data are correct), remains independent of, and an appropriate means to examine, psychoacoustic data and assumptions.

Acoustic Stimulation↗

Lateral cervical nucleus in the cat: functional organization and characteristics.

1. The lateral cervical nucleus (LCN) was investigated with extracellular recordings in the anesthetized cat. A total of 556 LCN units were characterized; the locations of most of these were histologically verified. Half of these had receptive fields on the rostral third of the ipsilateral body surface including the face; 14% had fields on the thorax or abdomen, 33% had fields on the hindlimb or tail, and about 3% had receptive fields larger than one limb. 2. The LCN was observed to be somatotopically organized in experiments using angled microelectrode penetrations. Hindlimb units were dorsolateral, forelimb units ventromedial, and face units most medial within the LCN. In regions where LCN cells were present only in the medial portion of the dorsolateral funiculus, they were all forelimb units. 3. A special subpopulation (17%) of cells were clustered most ventromedially in the LCN. These units had large or disjoint receptive fields, and/or responded to deep, visceral, or noxious stimulation. A third of these did not project in the medial lemniscus (ML); many were synaptically activated by stimulation of the ML. Those that did project in the ML had significantly longer latencies than all other LCN units. It is suggested that this subpopulation contains local LCN interneurons. 4. The specific mechanoreceptor inputs were identified for each of 121 projecting LCN units. Receptor inputs were uniform across each receptive field; that is, each unit that responded to a given receptor type was observed to respond to receptors of that type throughout its receptive field. Input from large-fiber-diameter, velocity-sensitive mechanoreceptors was predominant. The absence of input from slowly adapting type I and II receptors and from joint receptors was confirmed. A significant number of units (17.3%) could be driven by only one receptor type. The LCN sample profile agrees closely with the receptor representation in the hindlimb portion of the spinocervical tract. It is concluded that these data that anatomic specification of convergence occurs in the LCN with respect to receptor connectivity, and that this specification originates in lamina IV of the dorsal horn. 5. Stimulation of the dorsal column nuclei synaptically excited 23% of the LCN units tested. In two cases it was possible to demonstrate, by collision, that this occurred via collaterals of spinocervical tract axons. It is concluded that some spinocervical axons have collaterals terminating in the rostral parts of the dorsal column nuclei.

Animals↗

Hemispheric lateralization of motor and speech functions after early brain lesion: study of 73 epileptic patients with intracarotid amytal test.

This study reports results of a bilateral intracarotid amytal test in 73 epileptic patients with medically intractable focal seizures. No right-handers but 50% of left-handers have a right dominance for speech in this particular population. Lateralization of cerebral speech functions, as well as manual preference, are dependent on the neurological disease and can shift conjointly or independently. We study the relationships of those shifts to different variables related to the cerebral pathology: age at onset and lateralization of epilepsy, extensive brain damage, neurological deficit.

Adolescent↗