Exacerbated responses to oxidative stress by an Na(+) load in isolated nerve terminals: the role of ATP depletion and rise of [Ca(2+)](i).

We have explored the consequences of a [Na(+)](i) load and oxidative stress in isolated nerve terminals. The Na(+) load was achieved by veratridine (5-40 microM), which allows Na(+) entry via a voltage-operated Na(+) channel, and oxidative stress was induced by hydrogen peroxide (0.1-0.5 mM). Remarkably, neither the [Na(+)](i) load nor exposure to H(2)O(2) had any major effect on [Ca(2+)](i), mitochondrial membrane potential (Deltapsim), or ATP level. However, the combination of an Na(+) load and oxidative stress caused ATP depletion, a collapse of Deltapsim, and a progressive deregulation of [Ca(2+)](i) and [Na(+)](i) homeostasis. The decrease in the ATP level was unrelated to an increase in [Ca(2+)](i) and paralleled the rise in [Na(+)](i). The loss of Deltapsim was prevented in the absence of Ca(2+) but unaltered in the presence of cyclosporin A. We conclude that the increased ATP consumption by the Na,K-ATPase that results from a modest [Na(+)](i) load places an additional demand on mitochondria metabolically compromised by an oxidative stress, which are unable to produce a sufficient amount of ATP to fuel the ATP-driven ion pumps. This results in a deregulation of [Na(+)](i) and [Ca(2+)](i), and as a result of the latter, collapse of Deltapsim. The vicious cycle generated in the combined presence of Na(+) load and oxidative stress could be an important factor in the neuronal injury produced by ischemia or excitotoxicity, in which the oxidative insult is superimposed on a disturbed Na(+) homeostasis.

[Simultaneous occurrence of moyamoya disease and subclavian steal syndrome]. / A moyamoya betegség és a subclavian steal syndroma együttes elöfordulása.

The authors present a case of moyamoya disease associated with subclavian steal syndrome. They could not find any report in literature about the combination of these syndromes. The Doppler, MR, and angiographic findings as well as the clinical importance of subclavian steal and moyamoya syndromes are briefly summarized.

[Transcranial Doppler sonographic study of the effect of electroconvulsive therapy on the circulation in the median cerebral artery]. / Az electroconvulsiv kezelés transcranialis Doppler sonographiás módszerrel megfigyelt hatása az arteria cerebri media keringésére.

The authors monitored the circulation of middle cerebral artery in subdominant hemisphere using the transcranial Doppler sonographic method during electroconvulsive treatment. They intravenously administered the patient 500 mg propanididum to put him/her to sleep and 150 mg of suxamethonium for muscle relaxation. The phasis of narcosis and awakening were continuously recorded under the treatment. After the administration of propanididum a sudden brief rise in flow velocity was measured with transient bradycardia followed by tachycardia. After the muscle relaxation the peak flow velocity diminished long lasting and the mean flow velocity fell from 60 cm per second to 30 cm per second average. At the beginning of the electroconvulsive treatment the velocity suddenly rose. The flow velocity increased significantly during the clonic phase of convulsive jerks with the pulsatility indices falling rapidly. Very low pulsatility indices lasted for long period of time during and following clonic convulsions.

[Subclavian steal syndrome examined by transcranial Doppler sonography]. / A subclavian steal syndroma transcranialis Doppler sonographiás leletéröl.

Authors are presenting the diagnostic problems of subclavian steal syndrome, they are using the transcranial Doppler sonography (TCD). This method completes the traditional sonographic possibilities. With help of specific signs there is the possibility to confirm the clinical diagnosis and we can reach data from the dynamic of cerebral circulation and the situation of the circulation of the intracerebral collateral system, too. Authors briefly summarise the clinical signs of subclavian steal syndrome and the verification of the signs and the opinions, concerning the angiographic and sonographic method and the possibilities of surgical treatment.

[Transcranial Doppler sonography]. / A transcranialis Doppler sonographia.

The authors present the method of transcranial Doppler sonography and that technic of this method, too. Briefly describe the clinically important physical parameters. They present the possibility of use this method in clinical practice, referring the frequency analysis, the investigation of flow figures in the cerebrovascular diseases, respectively in stenosis, occlusions, malformations of blood vessels and the diagnostic possibilities in aneurysms.

The primate as a model for the human temperature-sensing system: 1. Adapting temperature and intensity of thermal stimuli.

The thermal sensitivity of three humans and two rhesus monkeys was measured behaviorally, using the "yes-no" paradigm of the Theory of Signal Detection. The aim was to evaluate the monkey's thermal-sensing system as a model for that of humans. Three of the principal variables of human thermal sensations--rate of the temperature change, area of stimulation, and site of stimulation--were held constant. The other three variables--adapting skin temperature (AT), intensity, and direction of the temperature change--were varied systematically. Systematic differences between species were not evident for warming or cooling stimuli. Isodetectability curves (d'e = 1) for small cooling stimuli plotted as a function of the AT were isomorphic, and the points for the human and monkey subjects were frequently superimposed. Isodetectability curves for warming stimuli, on the other hand, had similar shapes for ATs between 33 degrees and 40 degrees C, but the points for the different subjects were not superimposed. At ATs below 30 degrees C, one of the two humans in the warming series and the two monkeys continued to show similarly shaped curves, but the other human was markedly different. Qualitative descriptions of the thermal sensations obtained during threshold measurements of human subjects, reported previously, suggest that this unusual subject probably adopted a criterion qualitatively different from that used by the other subjects. The data presented here and in combination with previously published work from this laboratory (Kenshalo, 1970) suggest that thermal stimuli produce similar sensations in rhesus monkeys and humans, and that the neural systems responsible for coding AT and temperature change in the two species are fundamentally similar.

Collateral sprouts are replaced by regenerating neurites in the wounded corneal epithelium.

Following various types of wounds and subsequent denervation, the reinnervation of the rabbit corneal epithelium was found to occur in two distinct phases that overlapped in time. In the first phase large numbers of collateral sprouts originated from the unmyelinated plexus at various distances proximal to the site of transection. Light and electron microscopic observations revealed that the sprouts began to degenerate about 7 days after wounding. Collateral sprouts were replaced by an equally numerous population of regenerating neurites extending from the transected stumps of the pre-terminal axons. We conclude that, in the wounded cornea, normal neurology is reconstituted by regenerating neurites, and not by collateral sprouts, which proliferate and then degenerate early in the healing process.

RIPS: a UNIX-based reference information program for scientists.

A set of programs is described which implement a personal reference management and information retrieval system on a UNIX-based minicomputer. The system operates in a multiuser configuration with a host of user-friendly utilities that assist entry of reference material, its retrieval, and formatted printing for associated tasks. A search command language was developed without restriction in keyword vocabulary, number of keywords, or level of parenthetical expression nesting. The system is readily transported, and by design is applicable to any academic specialty.

Neural remodeling following experimental surgery of the rabbit cornea.

Wounding of the cornea results in extensive damage to the innervation that must be repaired to restore its normal structure and function. Four types of experimental wounds were produced in the corneas of young albino rabbits: 180 degrees penetrating perilimbal incisions, 4-mm central circular keratectomies and keratotomies, and radial keratotomies. Following perilimbal incisions, the denervated half of the cornea was reinnervated primarily by regenerating nerves that penetrated the limbal scar tissue. New neural growth from the innervated portion of the cornea provided a minor contribution to the denervated area. The regenerative response of the nerves following nonpenetrating procedures was found to be a biphasic process. In the first phase, a short period of degeneration of all nerves within the area enclosed by the wound boundary overlapped in time with the appearance of long, large caliber, dense neurites that coursed perpendicularly to the wound margins. The neurites originated from the intact subepithelial plexus at some distance from the wound margins. The second phase was initiated by the degeneration of the wound-oriented neurites and the concomitant appearance of a second generation of neurites. These new neurites originated from the transected stumps of the regenerating subepithelial axons at or near the wound margins. The oblique disposition of the second wave of neurites was similar to that of basal leashes in normal corneas. Nonpenetrating wounding procedures exhibited similar neural remodeling principles. In both types of keratotomies, nerve endings terminated within the wound in enduring and densely packed neuroma-like arrangements, while in keratectomies, nerve endings continued to grow toward the center of the cornea.