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Biomedical subjects

C J Hodge

Publications and source records attributed to C J Hodge.

At least 37 records · Page 2Linked to original sources
PubMed1989

Primate spinothalamic pathways: III. Thalamic terminations of the dorsolateral and ventral spinothalamic pathways.

The termination sites of the dorsolateral (DSTT) and ventral (VSTT) spinothalamic pathways were determined by using anterograde transport of horseradish peroxidase from the lumbar spinal cord in primates. One animal had no spinal cord lesion, while of two other animals, one received a midthoracic dorsolateral funiculus lesion, and the other received a midthoracic ventral quadrant lesion contralateral to the injection. The thalamic label in the animal with no spinal cord lesion was much less than the label in the two animals with spinal lesions. Moreover, in the animals with spinal lesions, HRP-labeled cells were found within the thalamus. Therefore, the remaining six animals received ipsilateral hemisections and bilateral dorsal column lesions, irrespective of the contralateral lesions. The thalamic label in the animals without contralateral lesions were assumed to represent the total spinothalamic input to the diencephalon. In these animals, label was located mainly in suprageniculate and pulvinar oralis, caudal and oral divisions of ventral posterior lateral nucleus, the lateral half of ventral posterior inferior nucleus, and zona incerta, while in the medial thalamus label was primarily in two distinct bands in medial dorsal nucleus and in the posterior dorsal portion of central lateral nucleus. Scattered lighter labeling was found in other thalamic nuclei. The pattern of terminal labeling observed in the ventral posterior lateral region was arranged in patches, while elsewhere in the thalamus a more uniform labeling pattern was observed. The thalamic label in animals with contralateral ventral quadrant lesions represented the terminations of the DSTT, while the label in animals with contralateral dorsolateral funiculus lesions represented VSTT terminations. The labeling pattern was similar between these two groups. However, there were small differences between them. These results indicate that DSTT and VSTT terminations largely overlap and innervate the lateral and medial thalamamus.

Animals↗
PubMed1989

A cryogenic device for reversibly blocking transmission through small regions of the spinal cord white matter.

A simple cryogenic device is described. This device is capable of cooling neural tissue in contact with the probe and maintaining the tissue at the desired temperature for extended periods of time. The cold probe can thereby reversibly block neural transmission through small portions of the spinal cord white matter. Interruption of axonal transmission is achieved by placing the tip of the device in contact with the exposed surface of the spinal cord and cooling the tip of the probe to -1 to +2 degrees C. The investigator monitors the tip temperature and adjusts the pump rate to maintain a constant tip temperature. The cross-sectional area under the probe where effective transmission block is achieved is about 1.5 mm2 which approximates the size of a single funiculus in the cat thoracic spinal cord. The cryogenic device was constructed for less than $700. The properties of this device were studied in physiologic experiments in cats. This device reversibly, selectively and repeatedly blocked the ascending mass action potential in the dorsolateral funiculus, transmission through ascending spinal axons in the dorsal columns, transmission through axons of spinal dorsal horn cells, the descending inhibitory input to the dorsal horn and the activity of thalamic nociceptive neurons. The reversible cold block effects on single units were observed for the duration of the experiments (up to 18 h) with no detectable damage to the underlying tissue. The physiologic effects of the cold block were usually reversed a few minutes after rewarming, although in some cases it took up to 40 min for the complete reversal of the cold block. This cryogenic device is useful for studying spinal cord pathways.

Animals↗
PubMed1989

Operative angiography by intraarterial digital subtraction angiography: a new technique for quality control of carotid endarterectomy.

Fifty patients who had carotid bifurcation endarterectomy as their sole surgical procedure underwent intraoperative completion angiography by means of portable intraarterial digital subtraction angiography. All had subsequent intravenous digital subtraction angiography or duplex scanning during early follow-up. After the endarterectomy site was closed and before the wound was closed, 6 to 8 ml of contrast was injected through a 21-gauge needle while fluoroscopy was performed with a conventional C-arm. The C-arm was coupled to a Quantel IDIS Mobile Digital Subtraction Angiogram Unit (Quantel Medical Products Group, Clemmons, N.C.) for image enhancement and immediate playback. There were no postoperative deaths or neurologic complications. Abnormal radiographic results led to reopening of endarterectomy sites in eight patients, which resulted in successful correction of the defects. There was a single asymptomatic occlusion of the internal carotid artery at 3 weeks in the patient with the only false-negative result on the completion study. Intraarterial digital subtraction angiography is a safe and useful technique for intraoperative quality control of carotid endarterectomy. It provides visual images that can be easily repeated in several projections, uses small volumes of contrast, and has no timing requirements for filming and injecting.

Carotid Artery Diseases↗
PubMed1989

Medial, intralaminar, and lateral terminations of lumbar spinothalamic tract neurons: a fluorescent double-label study.

A dorsolateral spinothalamic tract (DSTT), consisting primarily of lamina I neurons, was confirmed in the cat lumbar spinal cord by the use of thalamic injections of fluorescent dyes combined with selective thoracic spinal cord lesions. In addition, collateralization of spinothalamic tract (STT) terminations to medial, lateral, and intralaminar thalamic regions was investigated by injections of two different fluorescent dyes into pairs of these regions. The results of this study indicate that less than 15% of cat lumbar STT neurons collateralize to more than one of the thalamic regions evaluated. Lumbar lamina I cells project to the lateral and to the medial thalamus (13% collateralize to these two regions) and have only a scant projection to the intralaminar thalamus. Lumbar laminae IV-VI STT cells are very few in cat and demonstrate almost no collateralization to multiple thalamic areas. Neurons of laminae VII-X project equally to the three thalamic regions evaluated, and approximately 10-14% of cells from this laminar group collateralize to any two of the thalamic sites evaluated.

Animals↗
PubMed1988

Early clinical experience with the Syracuse I-Plate: an anterior spinal fixation device.

Sixteen patients were treated with a new anterior internal fixation device after thoracolumbar or lumbar decompression, and fusion with bone grafting. Ten patients had acute burst fractures, four had metastatic tumors, and two had old, healed fractures with deformity. In the acute fracture group, eight patients had neurologic deficits and seven patients experienced improvement. Six patients had lesions of the conus medullaris, all of which improved. The four patients with metastatic tumors underwent surgery for back and leg pain and all gained significant relief. Two patients had correction of old fracture deformity with satisfactory outcome. Complications were minimal. The new anterior stabilization device provided early stability, allowed early patient mobilization, was easy to insert, and has a low profile. Late collapse, non-union, and kyphotic deformity have not been noted thusfar.

Acute Disease↗
PubMed1987

The spinothalamic tract: an examination of the cells of origin of the dorsolateral and ventral spinothalamic pathways in cats.

The locations of spinothalamic neurons and the funicular trajectories of their axons were studied in cats by retrograde transport of horseradish peroxidase (HRP). Five animals were used as controls to determine the cervical and lumbar laminar distributions of neurons contributing to the spinothalamic tract. An additional eight animals were used to determine the funicular trajectories of the spinothalamic axons of lumbar neurons by utilizing a series of thoracic spinal cord lesions in conjunction with retrograde transport of HRP from the sensory thalamus. Three of these animals underwent midthoracic ventral quadrant lesions, four animals underwent midthoracic dorsolateral funiculus lesions, and one animal underwent total spinal cord transection sparing the dorsal columns. The locations of the cells containing the HRP reaction product were then determined after a 3- to 5-day survival time, and the patterns of labeled cell locations of the lesion groups were compared to the control group patterns. In the lesioned animals, the cervical spinothalamic cell locations were used as a control to confirm the uniformity of the injection sites, transport and tissue processing. The major finding of this study is that there exist two distinct components of the spinothalamic tract. The dorsolateral spinothalamic tract (DSTT) is made up of axons originating in contralateral spinal cord lamina I and has negligible contribution from the deeper spinal cord laminae. The axons of lamina I cells cross segmentally and ascend exclusively in the dorsolateral funiculus (DLF). The DSTT comprises approximately 25% of the total spinothalamic input from the lumbar enlargement. The ventral spinothalamic tract (VSTT) is made up of axons originating in spinal cord laminae IV-V and VII-X. Very few lamina I cells contribute axons to the VSTT. This crossed pathway ascends in the ventrolateral and ventromedial portions of the spinal cord. No cells contributing to the spinothalamic tract were identified in spinal cord segments caudal to a dorsal column sparing lesion, indicating that there are no spinothalamic tract axons traveling in the dorsal columns. These results expand the classical concept of information processing by the spinothalamic tract. The DSTT is made up of lamina I cell axons. All lamina I spinothalamic cells respond exclusively to noxious peripheral stimuli. Hence the DSTT is a major nociceptive-specific ascending spinal pathway, yet lies outside the confines normally assigned to the spinothalamic tract.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Computed tomographic evaluation of extracranial carotid artery disease.

Axial computed tomographic (CT) scans after intravenous contrast infusion were used to image the cervical carotid arteries of patients with cerebral ischemic symptoms. Standard transfemoral cervical carotid and cerebral angiography was the principal diagnostic modality used in all patients studied. The angiographic results were compared to the CT images and to the gross and microscopic endarterectomy pathological specimens, when available. Examples of the various types of abnormalities that can be visualized using CT scans are presented. The CT scan was useful for determining the presence of degenerative atheromatous changes including carotid artery calcification, subintimal hemorrhage, carotid occlusion, carotid segmental occlusion, and carotid pseudoocclusion, as well as carotid artery dissection. The scans were particularly useful for identification of atheromatous carotid artery disease when the carotid angiogram appeared nearly normal and for identifying the cause of postoperative carotid stenosis. CT scanning allows visualization of the carotid artery wall and lumen rather than just the lumen and, consequently, can sometimes add helpful information about the pathological processes affecting this artery.

Arterial Occlusive Diseases↗
PubMed1987

Spontaneous dissection of the cervical internal carotid artery: correlation of arteriography, CT, and pathology.

Spontaneous dissection of the internal carotid artery is being recognized as a more frequent cause of acute neurologic deficit, particularly in young persons. Saccular pseudoaneurysm formation may be an associated finding, especially in the presence of tortuosity (coiling) of the cervical internal carotid artery. Of eight patients with nine vessels demonstrating internal carotid artery dissection on arteriography, pseudoaneurysms were found in five arteries. Four of the five pseudoaneurysms occurred in tortuous (coiled) arterial segments. Thin-section contrast-enhanced dynamic incremental CT showed close agreement with the findings on selective arteriography and provided additional information on the presence and configuration of arterial wall thickening as well as the extent of the pseudoaneurysm. Our experience indicates that CT may play an important role in the diagnosis, management, and follow-up of this lesion.

Adult↗
PubMed1986

Transient neurological deficit after therapeutic embolization of the arteries supplying the medial wall of the hemisphere, including the supplementary motor area.

A 27-year-old, right-handed woman underwent intraoperative embolization for a left parasagittal arteriovenous malformation as part of a two stage plan that included subsequent surgical resection of the arteriovenous malformation. This report describes the neurological syndrome that developed after the first procedure. The relation of these deficits to localization of function within the supplementary motor area are correlated with recent advances in our understanding of this region.

Adult↗
PubMed1986

Inhibition of dorsal-horn cell responses by stimulation of the Kölliker-Fuse nucleus.

The Kölliker-Fuse nucleus (KF) in the dorsolateral pons has been shown to be the major source of catecholamine innervation of the spinal cord. This has important implications in terms of pain control mechanisms, since catecholamine-mediated mechanisms are essential for the expression of opiate and other varieties of antinociception. This study examines the effects of KF stimulation on responses of dorsal-horn cells to innocuous and noxious cutaneous stimuli in anesthetized cats. Stimulation of the KF potently inhibits the responses of dorsal-horn cells to both noxious and innocuous stimuli. The threshold for the inhibitory effect is significantly lower for responses to noxious stimuli as opposed to innocuous stimuli. The inhibitory effect is specific to the stimulus site, as evidenced by a marked decrease in the effect following small changes in the position of the stimulating electrode in the brain stem. The latency of the effects indicates a bulbospinal conduction velocity of 4 to 5 m/sec, which is much slower than usual reticulospinal effects and is consistent with a catecholamine-mediated system. The dependence of KF-spinal inhibition on intact biogenic amines was tested by depleting the animals of these amines with reserpine pretreatment. Depletion of biogenic amines resulted in a significant decrease in the KF spinal inhibitory effects, suggesting their dependence on intact noradrenergic stores. The results of these studies are consistent with the idea that the KF-spinal system plays an important noradrenergic-dependent role in the brain-stem modulation of spinal processing of noxious, potentially painful stimuli.

Animals↗
PubMed1985

Funicular course of catecholamine fibers innervating the lumbar spinal cord of the cat.

The purpose of this study was to determine the funicular location of descending catecholamine (CA) fibers innervating the lumbar spinal cord from the dorsolateral pons (DLP). The locations of catecholamine-containing cell bodies which project to the lumbar spinal cord were determined by combining the use of the retrogradely transported fluorescent dye, Evans Blue (EB), with the glyoxylic acid histofluorescence technique. Lumbar injections of Evans Blue were combined with thoracic lesions of the dorsolateral funiculi (DLF) or ventrolateral funiculi (VLF) in order to retrogradely label those CA-containing or non CA-containing cell bodies whose axons descend within the spared hemispinal cord. By this technique it was determined that descending CA fibers innervating the lumbar spinal cord of the cat project through both the DLF and the VLF. The nucleus subcoeruleus, the Kolliker-Fuse nucleus and the CA cell bodies in the area of A5 each contain a significant number of CA-containing cells whose fibers descend both within the DLF and the VLF, while the nucleus locus coeruleus projects to the lumbar cord primarily through the VLF. Catecholamine cells of the DLP innervate the lumbar spinal cord bilaterally, although there is an ipsilateral predominance. The CA-containing cells of the DLP which innervate the contralateral spinal cord were shown by ipsilateral or contralateral thoracic hemisection to decussate both above and below the thoracic lesion. Non-CA-containing cells from the DLP also crossed at all levels of the spinal cord; however, cells from the caudal pons had a larger number of cells which crossed above the thoracic lesion while cells of the more rostral pons had a larger number of cells which crossed below the lesion.

Animals↗
PubMed1985

A dorsolateral spinothalamic pathway in cat.

A spinothalamic tract that courses in the dorsolateral funiculus of the spinal cord and originates almost exclusively from spinal lamina I neurons has been demonstrated in the cat by retrograde transport of horseradish peroxidase. This tract is of special interest because the course of this predominantly lamina I, contralateral projection lies outside the classical course of the spinothalamic tract and because most lamina I cells contributing to the spinothalamic tract have been shown by other investigators to respond exclusively to somatic noxious stimuli. This newly described tract has important implications in the processing of noxious stimuli.

Animals↗
PubMed1985

Funicular location of ascending axons of lamina I cells in the cat spinal cord.

The laminar distribution of spinal cord neurons projecting suprasegmentally through different funiculi was determined in the cat using horseradish peroxidase (HRP) injections combined with selective spinal cord lesions. The lesions were designed to limit the caudal transport of HRP to either the ventral funiculi or the dorsolateral funiculus. HRP injections in the ventromedial or ventrolateral funiculi resulted in labeling primarily within laminae IV-VIII and a virtual lack of labeling within lamina I. When the dorsolateral funiculus was injected, 20-25% of all labeled cells were located in lamina I, bilaterally. These results demonstrate that the ascending lamina I projections are through the dorsolateral funiculus.

Afferent Pathways↗
PubMed1985

Sources of the catecholaminergic innervation of the trigeminal nucleus caudalis in cat.

Injections of the retrogradely transported fluorescent dye, Evans blue, into the trigeminal nucleus caudalis were combined with the glyoxylic acid histofluorescence technique to determine the sources of catecholamine-containing varicosities innervating nucleus caudalis. Results indicate that the sources of this catecholamine innervation are widespread, originating from cell bodies throughout the brain stem including the medullary catecholamine cell groups as well as the noradrenergic nuclei of the dorsolateral pons, including locus ceruleus, subceruleus, Kölliker-Fuse, and the parabrachial nuclei. A small projection from the presumably dopaminergic neurons of the hypothalamus was also noted. The catecholamine innervation of n. caudalis in the cat is from widespread brain stem sources, a pattern different from the catecholamine innervation of the spinal cord, which receives its major catecholamine input from the Kölliker-Fuse nucleus.

Animals↗
PubMed1985

Atheromatous extracranial carotid arteries: CT evaluation correlated with arteriography and pathologic examination.

Dynamic, rapid sequence, axial computed tomography (CT) was employed to evaluate the extracranial common and internal carotid arteries in 17 patients with clinical histories suggesting recent or remote ischemia in the territory supplied by the internal carotid artery. The CT findings were correlated with arteriographic observations and with gross and histologic evaluations of endarterectomy specimens. Areas of arterial wall thickening were evaluated on CT scans with regard to both degree of thickening and radiographic density (attenuation). The degree of vessel wall thickening secondary to atheromatous plaque demonstrated on CT scans corresponded closely to the severity of luminal compromise seen on arteriograms. Isodense or mildly hypodense focal mural thickening noted on CT scans of seven endarterectomy specimens proved to be primarily fibrotic (simple) atheromatous plaque on gross and histologic examination. Areas of markedly lucent focal mural thickening on CT scans of 11 specimens all demonstrated varying amounts of subintimal hemorrhage within loosely arranged and rather acellular (complex) atheromatous plaques on pathologic examination. While arteriography provides information regarding the status of the arterial lumen, CT offers the potential of accurate characterization of pathologic changes in the wall of the extracranial carotid arteries in patients with symptoms of cerebral ischemia.

Adult↗
PubMed1984

Lumbar dorsal root potentials elicited by stimulation of nucleus locus coeruleus.

Lumbar dorsal root potentials (DRP) were elicited by nucleus locus coeruleus (LC) stimulation in the cat. Inhibition, by LC stimulation, of dorsal horn cells responding to noxious inputs corresponded in time with the DRPs evoked by LC stimulation. Comparing cutaneous stimulation-evoked DRPs with LC stimulation-evoked DRPs and their respective effects on dorsal horn single-unit activity suggested a shared segmental underlying mechanism and the possible involvement of the coeruleospinal system with that of a diffuse noxious inhibitory suprasegmental loop.

Animals↗
PubMed1983

Changes in the effects of stimulation of locus coeruleus and nucleus raphe magnus following dorsal rhizotomy.

The effects of stimulating locus coeruleus (LC) and nucleus raphe magnus (NRM) on lumbar dorsal horn cells that had been denervated by dorsal rhizotomy were studied. Both LC and NRM stimulation inhibited the responses of dorsal horn cells from the side of the cord with intact dorsal roots. However, when cells from the side of the spinal cord that had had prior rhizotomies were studied, half of the units were shown to be activated by either LC or NRM stimulation.

Afferent Pathways↗