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Biomedical subjects

F R Sharp

Publications and source records attributed to F R Sharp.

At least 181 records · Page 10Linked to original sources
PubMed1985

Relation of HTLV-III seropositivity and lymphadenopathy.

Testing for antibody to human T-lymphotropic retrovirus (HTLV-III) was carried out in five groups of homosexual men: 250 without lymphadenopathy (control group), 37 with slight or nonpersistent lymph node enlargement (intermediate group), 141 with persistent generalized lymphadenopathy, 32 with persistent generalized lymphadenopathy who underwent biopsy and 11 in whom acquired immune deficiency syndrome (AIDS) was diagnosed. The rates of HTLV-III seropositivity in the five groups were 18%, 32%, 61%, 94% and 91% respectively.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Multiple vibrissae sensory regions in rat cerebellum: a (14C) 2-deoxyglucose study.

Repetitive tactile sensory stimulation of the right mystacial vibrissae (whiskers) was performed in awake, adult rats. Regions of increased (14C) 2-deoxyglucose (2DG) uptake were mapped autoradiographically in cerebellum. Predominantly ipsilateral activation of multiple discrete granule cell regions occurred in paramedian lobule, crus 2, crus 1, lobulus simplex, and anterior lobe hemisphere. Bilateral and contralateral activation of cerebellum did occur. Multiple small patches, as well as large granule cell regions, were activated. Mossy fiber afferents from the spinal trigeminal nuclei (particularly interpolaris), principal trigeminal sensory nucleus, and superior colliculus could account for metabolic activation of the granular layer. The slight metabolic activation of the molecular layer could have occurred from climbing or parallel fibers. Comparisons of the paramedian lobule granule cell regions activated during repetitive sensory stimulation of the vibrissae (RSSV) to those activated during vibrissae motor cortex stimulation (VMIS) showed regions only activated by RSSV, regions only activated by VMIS, and regions activated by both RSSV and VMIS. The granule cell regions activated during RSSV and VMIS were usually adjacent to or overlapping each other. Regions only activated during RSSV or only during VMIS could represent technical problems in trying to compare vibrissae motor and sensory pathways in two different groups of animals. Alternatively, cerebellar regions activated only during RSSV could process vibrissae tactile inputs. Regions activated only during VMIS could process vibrissae motor and perhaps proprioceptive sensory input. Regions activated during both RSSV and VMIS might process vibrissae proprioceptive sensory input and/or might represent loci where vibrissae motor, proprioceptive sensory, and tactile sensory convergence occur. The results raise the possibility that vibrissae motor, proprioceptive sensory, and tactile sensory pathways could be processed in separate granule cell patches in parts of cerebellum and in the same granule cell patches in other parts of cerebellum.

Afferent Pathways↗
PubMed1985

Vibrissae tactile stimulation: (14C) 2-deoxyglucose uptake in rat brainstem, thalamus, and cortex.

The right mystacial vibrissae of awake, adult rats were stroked at 4-6 times/second and brain regions which increased (14C) 2-deoxyglucose (2DG) uptake were mapped autoradiographically. The ventral parts of the ipsilateral spinal trigeminal nuclei pars caudalis (Sp5c), pars interpolaris (Sp5i), pars oralis (Sp5o), and the principal trigeminal sensory (Pr5) nuclei were activated. The lateral part of the ipsilateral facial (VII) nucleus (the region which innervates the vibrissae muscles) was also activated possibly via excitatory, trigeminal (Sp5c, Sp5i, Sp5o, Pr5) sensory afferents. A number of regions were activated contralateral to the sensory stimulus. Discrete patches of (14C) 2DG uptake occurred in deep layers of the superior colliculus (SCsgp). Dorsolateral and dorsomedial parts of the ventrobasal nucleus (VB), and posterior, dorsolateral parts of the reticular nucleus (R) of thalamus were activated, along with broad portions of the primary somatosensory cortex (SI) and second somatosensory cortex (SII). Though all layers of SI and SII cortex increased 2DG uptake, VB thalamic afferents to layers IV and Vc-Vla presumably accounted for the greater activation of these cortical layers during repetitive sensory stimulation of the vibrissae (RSSV). Activation of the above structures fits well with known anatomical data. However, the pattern of activation during RSSV was very different from that previously described during vibrissae motor cortex stimulation (VMIS). RSSV and VMIS both produced similar repetitive movements of all the mystacial vibrissae. However, only a few overlapping brain regions were activated during both RSSV and VMIS. These RSSV-VMIS overlap zones included Sp5o; rostral Sp5i; lateral VII; SCsgp; ventrobasal-posteromedial and ventrobasal-ventrolateral zones in thalamus; and a rostral region of SI probably anterior to the Woolsey vibrissae barrelfield in the dysgranular somatosensory (SI) cortex. Since RSSV and VMIS would both be expected to activate vibrissae proprioceptors, we have hypothesized that vibrissae proprioceptive input was processed in part in the RSSV-VMIS overlap zones. Convergence of motor-sensory inputs and other types of processing could have also occurred in these overlap zones.

Animals↗
PubMed1985

Lithium effects on selected circadian rhythms in rats.

Treating rats with lithium results in clear phase-delays in certain circadian rhythms but has no effect upon other rhythms. Phase-delays can be seen in running-wheel activity rhythms but under certain conditions, phase changes are not noted in SCN 2-DG uptake or pineal melatonin rhythms.

Animals↗
PubMed1984

Surgical management of primary motor disorders of the esophagus.

Primary motor disorders of the esophagus can be managed surgically with excellent results. Between the years 1972 and 1983, 40 patients were managed by us. The patients ranged in age from 14 to 79 years (mean 36.3 years). Thirty-six patients were managed primarily by the authors and 4 patients secondarily. The distribution of the hypodynamic states were achalasia in 29 patients, vigorous achalasia in 5 patients, and diffuse spasm in 1 patient, whereas the hyperdynamic states were squeeze syndrome in 2 patients, super-squeeze syndrome in 1 patient, and hypertensive lower esophageal sphincter in 2 patients. Of the 36 patients in hypodynamic states, 27 had a modified Heller myotomy and reconstruction of the gastroesophageal junction with a Belsey fundoplication and 9 had only a modified Heller myotomy. There was only one patient with reflux esophagitis. It occurred after myotomy and Belsey fundoplication for a hypertensive lower esophageal sphincter and hiatus hernia. Four patients were managed secondarily for complicated recurrent problems, one with a Belsey fundoplication and three with a jejunal interposition graft. We recommend myotomy, with or without a Belsey fundoplication, for management of primary motor disorders and avoidance of total Nissen fundoplication and a lengthening Collis gastroplasty.

Adolescent↗
PubMed1984

Cochlear deoxyglucose uptake: relationship to stimulus intensity.

The relationship between stimulus intensity and the uptake of 2-deoxyglucose (2-DG) in the cochlea of the gerbil was studied using an autoradiographic technique. In silence, incorporation of labeled 2-DG into stria vascularis and the spiral ligament was significantly higher than for other inner ear structures. With increasing intensity of noise exposure, 2-DG uptake in the spiral ganglion and VIIIth nerve increased dramatically when compared to the lateral wall structures. In contrast, relative 2-DG uptake in the organ of Corti was much less affected by noise exposure. Only at 105 dB SPL, the highest intensity tested, was a modest but statistically significant increase observed in the sensory epithelium. The small change in relative 2-DG uptake observed in the organ of Corti during acoustic stimulation is consistent with Davis' (1965: Quant. Biol. 30, 181-190) battery model of the cochlear transduction process. Alternatively, a larger change may have occurred, but been restricted to a small portion of the epithelium, such as one or both populations of hair cells.

Acoustic Stimulation↗
PubMed1984

Fetal frontal cortex transplant (14C) 2-deoxyglucose uptake and histology: survival in cavities of host rat brain motor cortex.

Fetal frontal neocortex from 18-day-old rat embryonic brain was transplanted into cavities in 30-day-old host motor cortex. Sixty days after transplantation, 5 of 15 transplanted rats had surviving fetal transplants. The fetal cortex transplants were physically attached to the host brain, completely filled the original cavity, and had numerous surviving cells including pyramidal neurons. Cell lamination within the fetal transplant was abnormal. The (14C) 2-deoxyglucose uptake of all five of the fetal neocortex transplants was less than adjacent cortex and contralateral host motor-sensory cortex, but more than adjacent corpus callosum white matter. The results indicate that fetal frontal neocortex can be transplanted into damaged rat motor cortex. The metabolic rate of the transplants suggests they could be partially functional.

Animals↗
PubMed1983

Metabolic activation of the brachium conjunctivum during induced hypothermia.

During hypothermia induced in ground squirrels by the halothane-heliox method, 2-deoxyglucose uptake of a white matter structure, the brachium conjunctivum, increased relative to the surrounding gray matter structures. The possibility of 2-deoxyglucose uptake by glial as well as neuronal elements in the brachium conjunctivum and the implications of this observation for the use of optical density ratios is discussed.

Acclimatization↗
PubMed1983

The relationship of local cerebral glucose utilization to optical density ratios.

The validity of optical density ratios used in [14C]2-deoxyglucose neuroanatomical mapping experiments is evaluated by comparing local cerebral glucose utilization (LCGU) and optical density (OD) ratios in the same animals. OD ratios are calculated by dividing the optical density of different gray matter structures by the optical density of a single white matter structure in each animal. OD ratios are linearly related to LCGU within a given animal including stimulated, highly activated regions. Anesthesia profoundly affects the relationship between LCGU and OD ratios, however, showing that OD ratios do not provide an accurate index of LCGU between animals in different physiological states. Anesthesia had only a slight effect on OD ratios, however, indicating that OD ratios may be helpful in assessing whether structures are functionally activated between animals in different physiological states.

Animals↗
PubMed1983

Relative 2-deoxyglucose uptake of the paratrigeminal nucleus increases during hibernation.

The paratrigeminal nucleus, a little-studied cell group of the medulla, is the only structure of the brain to significantly increase its relative [14C]2-deoxyglucose accumulation during hibernation in the ground squirrel. The zone of increased activity on the auto-radiographs is continuous between this structure and the marginal zone of the spinal trigeminal nucleus. Because of the known thermoafferent function of the latter structure, a similar function is suggested for the paratrigeminal nucleus.

Animals↗
PubMed1983

Focal increases of white matter glucose utilization produced by electrical stimulation of rat motor cortex.

The right motor cortex was electrically stimulated in adult, awake rats for 45 min. Local cerebral glucose utilization (LCGU) was measured in white matter pathways with the (14C)-2-deoxyglucose method. Stimulation increased LCGU in focal regions of the right internal capsule to 51.3 mumol/100 g/min, compared to 39.8 on the control left side. Stimulation also increased LCGU in the right, medial pontine pyramidal tract to 36.2 mumol/100 g/min, compared with 27.3 on the control left side. The data demonstrate that electrical stimulation of motor cortex neurons increases LCGU 30 to 40% in the efferent myelinated axons of those neurons.

Animals↗
PubMed1982

Autoradiographic patterns of hippocampal metabolism during induced hypothermia.

[14C]2-Deoxyglucose (2-DG) uptake in the hippocampal formation was studied in the ground squirrel subjected to induced hypothermia. Whereas the stratum lacunosum-molecular has the highest 2-DG uptake in the dorsal hippocampus during euthermia, 2-DG uptake in the stratum lacunosum-molecular and stratum radiatum are similar during hypothermia. This may indicate activation of a cholinergic input to the hippocampus during hypothermia.

Animals↗
PubMed1982

Regional (14C) 2-deoxyglucose uptake during vibrissae movements evoked by rat motor cortex stimulation.

Repetitive left mystacial vibrissae movements were produced by electrical stimulation of right motor cortex (MI) were a bipolar electrode in the alert, unanesthetized rat. Regional increases of (14C) 2-deoxyglucose (2DG) uptake were mapped autoradiographically during these left vibrissae movements. Uptake of 2DG increased in a 2-4-mm-diameter area about the stimulating electrode in right MI and in a smaller region in left MI cortex. Columnar increases of 2DG uptake occurred bilaterally in somatosensory cortex in the face region of somatosensory cortex (SI). Bilateral increases of 2DG uptake occurred subcortically in dorsolateral caudate-putamen (CP) and subthalamic nucleus. Primary right-sided increases of 2DG uptake occurred in other basal ganglia structures including dorsal globus pallidus (GP), posterior, entopeduncular nucleus (EPN), ventrolateral substantia nigra pars reticulata (SNr), and anterolateral substantia nigra pars compacta (SNc). Uptake of 2DG increased on the right side of the following thalamic regions: much of the ventrolateral (VL) nucleus, particularly dorsally; the anterodorsal reticular nucleus; dorsolateral posteromedial (POm) nucleus; the ventromedial nucleus; and dorsolateral parafasicular nucleus. The anterior and ventral posterior portions of VL were not activated. Caudal to thalamus right-sided 2DG uptake increased in the medial, ventral, and lateral pontine nuclei, deep layers of superior colliculus, lateral deep mesencephalic nucleus (DMN), and nucleus cuneiformis (NCU). UPtake of 2DG increased in right rostral parvocellular and red nucleus in a few animals. Discrete portions of the right internal capsule and right medial pyramidal tract increased 2DG uptake during MI stimulation. Uptake of 2DG increased on the left side of the brain during right MI stimulation in the left lateral nucleus (NL) of cerebellum and in several discrete regions of left cerebellar hemisphere granule cells including anterior paravermis, lobulus simplex, crus II, and the paramedian lobule. Uptake of 2DG increased in left nucleus of the spinal tract of the trigeminal nerve (ntV) ventrally in subnuclei interpolaris and oralis. Left lateral portions of the facial nucleus were activated in a few animals. The lateral portions of the facial nucleus are known to project to vibrissae musculature. All of the above structures may be involved in the motor-sensory processing responsible for vibrissae movements. Regions not previously suggested to play a major role in vibrissae movements include DMN and NCU. Though NCU has been called the "locomotor center" it may play a role in facial movements as well. Polysynaptic activation of GP, EPN, NL, and cerebellar hemisphere occurred since no connections between MI and these regions exist. A pathway from ntV to POm to MI and SI is suggested to provide proprioceptive input to motor-sensory cortex from the moving vibrissae since neither the principal trigeminal sensory nucleus nor the ventrobasal nucleus of the thalamus increased 2DG uptake during MI stimulation.

Animals↗
PubMed1982

Tonotopic organization in the central auditory pathway of the Mongolian gerbil: a 2-deoxyglucose study.

The uptake of 2-deoxyglucose (2-DG) was employed to map functional activation of the central auditory pathway in the mongolian gerbil, during 85 dB SPL stimulation with pure tonal stimuli at frequencies of 0.75, 3.0, or 12.0 kHz. Pure tones produced foci of very high 2-DG uptake, when compared to adjacent tissue, in the cochlear nucleus, superior olivary complex, and inferior colliculus. Less distinct areas of elevated 2-DG uptake were seen in the dorsal and ventral nuclei of the lateral lemniscus, medial geniculate nucleus, and auditory cortex. Little or no change in the distribution of 2-DG uptake was noted in the nucleus of the trapezoid body. The location of discrete regions of relatively high 2-DG uptake varied systematically with stimulus frequency. The tonotopic organization demonstrated by 2-DG mapping agreed well with the results of previous electrophysiological studies for most structures. However, in the inferior colliculus, stimulus-evoked increases in 2-DG uptake were found to occur in a fixed pattern of three to four bands across the central nucleus, which did not correspond to any previously reported anatomical or physiological organization. Pure tonal stimuli activated discrete portions of this banding pattern. Also, a small area at the ventromedial edge of the colliculus was more broadly tuned than other regions of the nucleus. It is concluded that 2-DG uptake is well suited to the investigation of tonotopic organization. This technique reveals patterns of activation which have not been observed with other methodologies.

Animals↗