Search PubMed⌕ Search

Biomedical subjects

C J Hodge

Publications and source records attributed to C J Hodge.

At least 55 records · Page 3Linked to original sources
PubMed1983

Dorsolateral pontine inhibition of dorsal horn cell responses to cutaneous stimulation: lack of dependence on catecholaminergic systems in cat.

The effect of stimulating the dorsolateral pons (DLP) in the region of locus ceruleus (LC) on lumbar dorsal horn cell responses to innocuous and noxious cutaneous stimuli was assessed and the dependence of these effects on intact pontospinal catecholaminergic systems was tested in chloralose-anesthetized cats. DLP stimulation inhibited the responses of dorsal horn cells to both noxious and innocuous skin stimuli. The inhibitory effect was most prominent when the responses to noxious stimuli were tested. The thresholds for eliciting DLP-spinal inhibition were lowest (less than 30 microA) in the region of LC. The inhibitory effect was found in both ipsilateral and contralateral dorsal horns. The DLP-spinal inhibition was unaltered by depletion of spinal catecholamines brought about by repeated lumbar intrathecal administration of 6-hydroxydopamine or systemic administration of reserpine. We conclude that the DLP-dorsal horn inhibition is not related to a catecholaminergic ceruleospinal system in the cat and that the dependence of pain modulation by catecholamine systems is a reflection of other descending pathways.

Animals↗
PubMed1982

Kölliker-Fuse nucleus: the principal source of pontine catecholaminergic cells projecting to the lumbar spinal cord of cat.

Using retrograde transport of the fluorescent dye Evans Blue (EB), in combination with glyoxylic acid histofluorescence, the ponto-spinal catecholaminergic pathways were investigated. The cells which contain catecholamine and project to the lumbar spinal cord of the cat are most densely concentrated in the Kölliker-Fuse nucleus. Locus coeruleus, the subcoeruleus area, and the parabrachial nuclei were found to have relatively few cells that both contain catecholamine and project to the lumbar spinal cord.

Animals↗
PubMed1982

Intracerebral hematoma after evacuation of chronic extracerebral fluid collections.

Among 140 cases of chronic extracerebral fluid collections treated surgically, 7 cases (5%) of intracerebral hematoma occurring immediately after drainage were encountered. In none of the patients was a preoperative intracerebral clot or contusion identified by either computed tomographic scan or angiography. One patient had pre-existing systemic hypertension. Five of the patients had chronic subdural hematomas, 1 had a subdural hygroma and had been previously radiated for medulloblastoma, and 1 patient had a middle fossa arachnoid cyst. Four of the group had had craniotomies and three had undergone trephination for the primary lesion. The postoperative intracerebral hematomas were manifest by rapid deterioration of consciousness and focal neurological findings occurring usually immediately (but, in 2 cases, a few days after) the original procedure. Five patients underwent secondary craniotomy and 2 had external drainage. Despite rapid treatment, 2 of the patients died, 4 were left with severe disability, and only 1 survived intact. None of the patients had identifiable coagulopathy, and only 1 patient was hypertensive in the immediate postoperative period. The factors that all of the patients had in common were preoperative increased intracranial pressure and shift of the midline structures, as well as rapid surgical decompression of the initial lesion. Possible pathogenic mechanisms include hemorrhage into previously undetected areas of contusion, a sudden increase in cerebral blood flow combined with faulty autoregulation, and damage to parenchymal vessels secondary to rapid intra- or postoperative shift of the intracranial contents. Perhaps this devastating complication can be avoided if closed system drainage is used for the treatment of chronic surface collections.

Adult↗
PubMed1982

Spontaneous dissecting cervical carotid artery aneurysm.

A unique case of a large dissecting cervical carotid artery aneurysm is presented. The lesion had probably started as a spontaneous dissection 2 years before the onset of ischemic hemisphere symptoms and represents one way in which such a dissection can evolve if unchecked. The usual presentation, angiographic findings, and possible treatments of dissecting extracranial carotid aneurysms are discussed briefly.

Aortic Dissection↗
PubMed1980

Noradrenalin, serotonin, and the dorsal horn.

There is anatomical, pharmacological, and physiological evidence that descending systems from the brain stem using noradrenalin and serotonin (5-hydroxytryptamine, 5-HT) participate in the control of segmental sensory processing. Study of these systems is described in this paper. L-dopa was given intravenously to cats to cause the release of noradrenalin and 5-HT. The resultant effects on the responses of dorsal horn cells to innocuous and noxious thermal stimulation of skin were determined. Using the catecholamine cell neurotoxin, 6-hydroxydopamine, the dopamine beta-hydroxylase inhibitor, fusaric acid, and the tryptophan hydroxylase inhibitor, parachlorophenylalanine, the available central stores of noradrenalin or 5-HT were altered, thus allowing separation of the effects of noradrenalin and 5-HT release on dorsal horn cells. The results indicate that noradrenalin facilitates the responses of dorsal horn cells to innocuous cutaneous stimuli, and has an inhibitory effect on the responses to noxious stimuli. Serotonin inhibits the responses of dorsal horn cells that respond to noxious stimuli, to both innocuous and noxious stimuli. The results are discussed in light of current developments concerning aminergic control of segmental sensory processing.

Animals↗
PubMed1979

The effects of L-dopa on dorsal horn cell responses to innocuous skin stimulation.

The effects of L-DOPA on responses of dorsal horn cells to innocuous mechanical skin stimulation were studied. Following intravenous administration of L-DOPA (10--40 mg/kg) to cats with intact spinal cords, dorsal horn cells, which could be activated by only innocuous or innocuous and noxious stimuli, demonstrated increased reponses manifested by an increase in the average number of spikes per stimulus, increased receptive field size and occasional changes in adequate stimuli. When cats with acute cord transections were studied, L-DOPA increased the responses of cells located in lamina 4 and those cells which responded only to innocuous stimuli; cells which responded to noxious stimuli and those located in other laminae had depressed responses following L-DOPA administration. The inhibitory effects of L-DOPA were in part abolished, in spinal cats, by pretreatment with parachlorophenylalanine, a serotonin depletor. Studies of dorsal cells in chronic spinal cats indicated that the effects of L-DOPA were largely dependent on functioning terminals of descending suprasegmental pathways. The conclusion was reached that descending noradrenergic pathways, indirectly, cause an increase in transmission from cutaneous afferents to dorsal horn cells and that some of the inhibitory effects of L-DOPA described by others are a manifestation of L-DOPA interactions with inhibitory serotonergic systems.

Animals↗
PubMed1978

Cerebral revascularization.

Cerebral vascular insufficiency due to occlusive lesions regarded as inaccessible is a common problem. The degree of cerebral dysfunction associated with such lesions is dependent in part on the amount of collateral circulation present. By anastomosing the superficial temporal artery to a branch of the middle cerebral artery an increase in collateral circulation is provided to the affected hemisphere. This report describes the results of twenty such procedures. Postoperative angiography demonstrates a 90% patency rate. There is frequent neurological improvement following surgery, and the rate of new TIA's or strokes seems less than would be expected. The most damaging complication of the procedure ist intracerebral haemorrhage. The indications for, and the complications of, such procedures are discussed.

Adult↗
PubMed1978

Intradural herniation of lumbar intervertebral discs.

A case of intradural rupture of a lumbar intervertebral disc is reported, and the literature is reviewed. The majority of intradural disc herniations occur at the L4--5 level. These patients usually have neurologic deficits more severe than those found in the much more common extradural disc herniations. The myelographic picture varies from an irregularly marginated intradural lesion overlying the disc space to a complete block. The common factor allowing intradural disc herniation is probably dense adhesions between the dura and the posterior longitudinal ligament, preventing the more common lateral extradural disc herniation. Intradural disc herniation should be included in the differential diagnosis of lumbar intradural lesions causing nerve root or cauda equina compression.

Adult↗
PubMed1976

Medical modification of sensation.

The authors describe the sensory examinations of 3 patients who had undergone cervical rhizotomy alone and in combination with trigeminal tractotomy and section of the nervus intermedius, the glossopharyngeal nerve, and the upper portion of the vagus nerve. Following administration of L-dopa there was an increase in their pain and a decrease in the area of clinically anesthetic or analgesic skin. When methyldopa was given, the subjective and objective changes were the opposite of those elicited by L-dopa. These observations support the existence of a wider dorsal root cutaneous distribution than is usually accepted as well as significant control of cutaneous sensation by suprasegmental areas of the central nervous system. Part of the suprasegmental bias supplied to the area in the spinal cord that processes sensory information apparently occurs by way of an aminergic descending reticulospinal tract. These findings are discussed in terms of attempts totally to denervate restricted cutaneous areas of the body for treatment of pain-producing states.

Adult↗