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PubMed1998

The distribution of primary afferent terminals from the eyelids of macaque monkeys.

Trigeminal sensory afferents from the eyelids convey two types of information that are important for the blink reflex. Movement of the lashes activates low-threshold mechanoreceptors which evoke protective blinks. Information about eyelid position is also transmitted centrally and is used to adapt the metrics of the blink reflex to changing conditions over time. This study employed transganglionic transport of horseradish peroxidase conjugated to choleratoxin-B subunit or wheat-germ agglutinin to investigate trigeminal afferents supplying the eyelids of macaque monkeys. Ganglion cells labeled from upper- and lower-lid injections were located in the ophthalmic and maxillary portions of the trigeminal ganglion, respectively. In both cases, labeled terminals were observed ipsilateral to the injected eyelid in the principal and spinal trigeminal nuclei. However, only a few labeled terminals were present in the principal nucleus, and very sparse terminal labeling was confined to a few locations along the ventral border of the pars oralis and interpolaris of the spinal trigeminal nucleus. The main concentration of label was found in the pars caudalis at and immediately below the spinomedullary junction. The terminal field from the upper eyelid was located ventrally in the pars caudalis, and that from the lower eyelid was located more dorsally. In both cases, the labeled terminal field was densest within lamina II of the spinal trigeminal nucleus. The heavy concentration of eyelid central terminals at the spinomedullary junction is surprising in light of physiological studies indicating representation of all parts of the face throughout the trigeminal nucleus. The distribution of eyelid afferent terminals in the macaque is caudal to the main concentration of corneal afferent terminals at the pars interpolaris/caudalis border. This may be a basis for differences seen in blinks produced by corneal as opposed to supraorbital stimulation. The presence of a single major site of eyelid primary afferent terminals suggests that sensory input for both eyelid proprioception and blink-reflex activation passes through this segment of the spinal trigeminal nucleus. These results provide a basis for investigation of the central connections of pars caudalis neurons in order to better establish the pathways producing trigeminally evoked blinks and blink adaptation.

Adaptation, Physiological↗
PubMed1998

Steps toward recovery of function after hemilabyrinthectomy in frogs.

Removal of the labyrinthine organs on one side results in a number of severe postural and dynamic reflex deficits. Over time some of these behavioral deficits normalize again. At a chronic stage the brain of frogs exhibits a number of changes in vestibular and propriospinal circuits on the operated side that were studied in vitro. The onset of changes in the vestibular nuclear complex was delayed, became evident only after head posture had recovered by more than 50%, and was independent of the presence or absence of a degeneration of vestibular nerve afferent fibers. The time course of changes measured in the isolated spinal cord paralleled the time course of normalization of head and body posture. Results obtained after selective lesions of individual labyrinthine nerve branches show that unilateral inactivation of utricular afferent inputs is a necessary and sufficient condition to provoke postural deficits and propriospinal changes similar to those after the removal of all labyrinthine organs. The presence of multiple synaptic changes at distributed anatomic sites over different periods of time suggests that different parts of the central nervous system are involved in the normalization of different manifestations of the vestibular lesion syndrome.

Adaptation, Physiological↗
PubMed2005

[Cortical blindness associated with Guillain-Barre syndrome: a complication of dysautonomia?].

INTRODUCTION: We report a case of a Guillain-Barre syndrome (GBS) with subarachnoid hemorrhage and regressive occipital white matter lesions. OBSERVATION: A 62-year-old woman developed ascendant progressive paresthesia and weakness of arms and legs, 48 hours after enteritis infection. Neurological examination showed tetraparesia with loss of deep tendon reflexes and alteration of proprioception tests. Nerve conduction studies revealed polyradiculoneuritis. Then she presented an acute blindness and hypertension. Brain magnetic resonance imaging showed bilateral occipital lesions and subarachnoid hemorrhage. Cerebrospinal fluid analysis revealed an elevated protein level (1.54 g/l) and red blood cells without meningitis. Brain arteriography was normal. Intravenous immunoglobulins improved neurological symptoms. CONCLUSION: Posterior localisation of reversible white matter lesions evoked a reversible posterior leukoencephalopathy. The implication of arterial hypertension caused by dysautonomia during GBS could be suspected.

Autonomic Nervous System Diseases↗
PubMed1999

Regional musculoskeletal pain. The knee.

Chronic knee pain is common at all ages, particularly in the elderly, among whom it has its greatest impact. Chronic knee pain is often ascribed to osteoarthritis in adults and to chondromalacia patellae in children and adolescents. Pathological findings in both these conditions correlate poorly, however, with the severity of knee pain and disability. Psychometric variables correlate better with the impact of knee osteoarthritis, suggesting that this disorder has characteristics of a regional pain syndrome. This perception may reflect our lack of understanding of the biological mechanisms in these disorders. This possibility has been highlighted by the advent of magnetic resonance imaging, and by recent studies of muscle function, reflex quadriceps inhibition and proprioception in people with knee osteoarthritis. Established risk factors for knee osteoarthritis include increased body weight, knee injury and aspects of occupational activity. Recent studies have also suggested a possible role for oestrogens and vitamins C and D in the secondary prevention of this disorder. The emergence of 'nutraceuticals' such as glucosamine as treatments for osteoarthritis has captured the public imagination and merits further study.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Clinical and pathological observations in English cocker spaniels with primary metabolic vitamin E deficiency and retinal pigment epithelial dystrophy.

Fifteen English cocker spaniels with confirmed vitamin E deficiency were examined physically, ophthalmologically and neurologically. Eleven of them had clinical signs of neurological dysfunction which included ataxia, proprioceptive deficits, abnormal spinal reflexes and muscle weakness. In the two dogs examined histopathologically there was central neuronal fibre degeneration with prominent neuroaxonal dystrophy, particularly within the sensory relay nuclei of the brainstem, and one of the dogs had severe intestinal lipofuscinosis.

Animals↗
PubMed1981

Diaphragm electrical activity during negative lower torso pressure in quadriplegic men.

We recorded the diaphragm electromyogram (EMG) of quadriplegic men before and during exposure of the lower torso to continuous negative pressure, which caused shortening of the inspiratory muscles by expanding the respiratory system by one tidal volume. The moving-time-averaged diaphragm EMG was larger during expansion of the respiratory system. When we repeated the experiment with subjects who breathed through a mouthpiece, we found qualitatively similar EMG changes and little or no change in tidal volume or end-tidal CO2 partial pressure. When the pressure was applied or removed rapidly, changes in EMG occurred within one or two breaths. Because end-tidal CO2 partial pressure did not increase, and because the response was rapid, we suggest that the response results from proprioceptive, rather than chemoreceptive, reflexes. As most of these men had complete spinal lesions at C6 or C7 the afferent pathways are likely to be vagal or phrenic.

Adult↗
PubMed2003

Ethanol plus caffeine (caffeinol) for treatment of ischemic stroke: preclinical experience.

BACKGROUND AND PURPOSE: Ethanol and caffeine are 2 common psychoactive dietary components. We have recently shown that low-dose ethanol plus caffeine results in a 70% to 80% reduction of infarct volume after reversible common carotid/middle cerebral artery (CCA/MCA) occlusion in rats. The combination (caffeinol) was effective after either oral pretreatment or intravenous administration starting up to 2 hours after stroke onset. Ethanol alone aggravated ischemic damage, while caffeine alone was without effect. Daily caffeinol for 2 weeks before ischemia eliminated the neuroprotection seen with acute treatment (tolerance). The purpose of our present study was to further characterize the properties of caffeinol as a possible treatment for ischemic stroke. METHODS: The transient CCA/MCA occlusion model was used in all experiments. Five sets of experiments were conducted (1) to test the effectiveness of various doses of ethanol (0.2 to 0.65 g/kg) and caffeine (3 to 10 mg/kg) in the caffeinol mixture; (2) to test whether the neuroprotective dose of caffeinol can improve behavioral dysfunction; (3) to test whether chronic ethanol or caffeine before ischemia will affect efficacy of caffeinol treatment; (4) to test whether the protective effect of caffeinol can be improved by pairing it with 35 degrees C hypothermia; and (5) to test whether caffeinol affects frequency of hemorrhage after administration of recombinant tissue plasminogen activator (rtPA) in ischemic animals. RESULTS: Doses as low as 0.2 g/kg of ethanol and 6 mg/kg of caffeine in the caffeinol were effective in reducing cortical infarct volume and behavioral dysfunction after transient CCA/MCA occlusion. Daily exposure to ethanol but not caffeine before CCA/MCA occlusion eliminated the therapeutic efficacy of acute caffeinol treatment, similar to the tolerance observed after chronic exposure to caffeinol. The therapeutic effect of caffeinol could be further improved by pairing it with mild intraischemic hypothermia, and caffeinol did not increase hemorrhagic infarction when given in combination with rtPA. CONCLUSIONS: Low doses of caffeinol, equivalent to no more than 2 to 3 cups of strong coffee and 1 cocktail, are consistently and highly neuroprotective, are well tolerated, can be added to other therapies to increase the effect of each, and do not interfere with or complicate rtPA therapy. Caffeinol is an appropriate candidate for clinical trial in stroke patients, although it may be less effective in patients with regular alcohol intake.

Animals↗
PubMed1999

The knee

Chronic knee pain is common at all ages, particularly in the elderly, among whom it has its greatest impact. Chronic knee pain is often ascribed to osteoarthritis in adults and to chondromalacia patellae in children and adolescents. Pathological findings in both these conditions correlate poorly, however, with the severity of knee pain and disability. Psychometric variables correlate better with the impact of knee osteoarthritis, suggesting that this disorder has characteristics of a regional pain syndrome. This perception may reflect our lack of understanding of the biological mechanisms in these disorders. This possibility has been highlighted by the advent of magnetic resonance imaging, and by recent studies of muscle function, reflex quadriceps inhibition and proprioception in people with knee osteoarthritis. Established risk factors for knee osteoarthritis include increased body weight, knee injury and aspects of occupational activity. Recent studies have also suggested a possible role for oestrogens and vitamins C and D in the secondary prevention of this disorder. The emergence of 'nutraceuticals' such as glucosamine as treatments for osteoarthritis has captured the public imagination and merits further study.

Journal Article↗
PubMed1977

[Assessment of the role of the sensory innervation of the intraocular muscles in habituation of vestibulo-oculomotor reactions].

In rabbits, participation of the extraocular muscles' sensitive innervation in extinguishing of the eyes nystagmus elicited by periodical rotations, was studied. Either limitation or complete abolishing of the above muscles motor activity were used, as well as the passive forced movements of the eyes. No considerable difference was revealed between the intact and the experimental animals. In both cases the course of nystagmus extinguishing was the same. On the other hand, repeated forced movements of the eye had no effect on the reflectory evoked nystagmus. The data obtained suggest that the proprioceptive afferents of the extraocular muscles take no part in the habituation of vestibular-oculomotor responses.

Animals↗
PubMed1988

Arterial thromboembolic disease in a dog with blastomycosis localized in a hilar lymph node.

An 8-year-old mixed-breed dog was evaluated for caudal paresis. Transient lameness of the left hind and left forelimbs had developed during the preceding week. Clinical findings included conscious proprioceptive deficits, hyporeflexive tendon reflexes and decreased pain perception, coolness in the hind limbs and left forelimb, and absence of femoral pulses. A fluid-dense mass was radiographically identified adjacent to the left atrium. Echocardiography revealed a mass in the left atrium and spontaneous contrast in the left ventricular lumen and aortic root. The dog was euthanatized because of its deteriorating condition. A large mass was adhered to the dorsal left atrial wall and had eroded into the atrial lumen. A sterile blood clot was attached to this site, and sterile thrombi were in the terminal portion of the aorta. Histologically, the mass was found to be hilar lymph node with chronic pyogranulomatous inflammation containing organisms characteristic of Blastomyces dermatitidis.

Animals↗
PubMed1988

Neuroaxonal dystrophy in a rottweiler pup.

An 8-month-old Rottweiler pup was evaluated for neurologic disorder. Clinical signs included ataxia, hypermetria of all 4 limbs, intention tremors of the head, lack of a menace reflex bilaterally, and mild proprioceptive deficits. The pup was euthanatized because of the progressive nature of the disease. Histopathologic findings consisted of decreased numbers of Purkinje cells in the cerebellum and moderate numbers of axonal spheroids in the nucleus cuneatus. This latter finding confirmed the diagnosis of neuroaxonal dystrophy.

Animals↗