Biomedical subjects
Publications and source records attributed to J Graham.
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Waste from disused lead mines is used for a variety of purposes and has been implicated in outbreaks of lead poisoning in animals. Three outbreaks of lead poisoning, two in cattle and one in farm dogs, occurred in the south of Scotland. In the first outbreak, three housed suckler cows died and two were clinically affected but recovered after treatment. In the second, four heifers died and two recovered after therapy. Blood samples taken from cattle in both outbreaks contained lead in concentrations from 0 . 59 to 2 . 00 ppm (normal blood lead level 0 . 05 to 0 . 25 ppm). Post mortem examinations revealed signs of lead poisoning. Metallic particles in the rumens and abomasums of affected animals suggested mine waste as the source of the lead and subsequently it was found that the material had been used in the construction of a ramp over which silage was pushed (outbreak 1) and to fill potholes on the farm (outbreak 2). Covering the relevant areas with concrete prevented further occurrences. Farm dogs were affected over a period where mine waste was used to resurface a road. Two dogs died, six others showed signs of lead poisoning and others, with no clinical signs, had elevated blood lead levels.
Subcortical connections of the striate cortex with the superior colliculus (SC), the lateral pulvinar (Pl), the inferior pulvinar (Pi) and the dorsal lateral geniculate nucleus (LG) were studied in the macaque monkey, Macaca fascicularis, following cortical injections of tritiated proline and/or horseradish peroxidase. All four structures were shown to receive topographically organized projections from the striate cortex. The exposed surface of the striate cortex was found to be connected to the rostral part of the SC and the caudal part of the LG. Injections of the exposed striate cortex close to its rostral border resulted in label in adjoining parts of the Pl and Pi. The ventral half and dorsal half of the calcarine fissure were connected with the medial and lateral parts of the SC, the ventrolateral and dorsomedial portions of the Pl and Pi and the lateral and medial parts of the LG, respectively. Injections located at the lateral posterior extreme of the calcarine fissure resulted in label at the optic disc representation in the LG. The horseradish peroxidase material demonstrated that LG neurons in all laminae and interlaminar zones project to the striate cortex.
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Forty-four patients with Haemophilus influenzae type b meningitis had follow-up evaluations approximately one year after hospital discharge. Patients with greater than or equal to 10(7) colony-forming units of H. influenzae type b per milliliters CSF had significantly greater frequencies of speech impairment (P less than 0.001), hearing loss (P = 0.04), and moderate or severe neurologic sequelae (P less than 0.01). Patients with greater than or equal to 1 microgram H. influenzae b antigen/ml CSF had a greater incidence of hearing loss (P = 0.03) but not of speech abnormalities (P = 0.06) or other neurologic sequelae (P = 0.64). Glucose concentrations less than 10 mg/dl correlated with the incidence of hearing loss (P = 0.02) and speech impairment (P = 0.02). "Partial" antibiotic therapy, CSF protein concentrations, and number of CSF polymorphonuclear leukocytes did not correlate well with sequelae. These data indicate that pretreatment concentrations of H. influenzae b and glucose concentrations in CSF were the best predictors of late sequelae of patients with H. influenzae b meningitis.
1. One hundred seventy-nine single units were studied in the superior colliculus of seven Dutch-belted rabbits following ablation of the ipsilateral visual cortex. The response characteristics of these units were compared with those of 284 single units recorded from the superior colliculus of 20 intact animals. 2. In both the upper and lower parts of the stratum griseum superficiale and in the stratum griseum intermediate, there were smaller proportions of direction-selective visual units in the decorticated animals than in normal ones. 3. In the upper stratum griseum superficiale, a larger proportion of units responded to stroboscopic illumination in the decorticated animals than in normal ones. Also, in the decorticated animals, there was a larger proportion of units whose responses to a small moving stimulus were inhibited by the simultaneous presentation of stroboscopic illumination. 4. In both the upper and lower parts of the stratum griseum superficiale, a larger proportion of visual units responded well to stationary stimuli and a smaller proportion of visual units showed habituation in decorticated animals compared to normal ones. 5. In the lower stratum griseum superficiale, the receptive fields of units were larger and were more elongated in the anterior-posterior dimension in the decorticated animals than in normal ones. 6. In the two preparations, units did not differ in responsiveness or spontaneous activity; and visual units did not differ in the sustained or transient nature of their responses, the selectivity for light or dark stimuli, the selectivity for onset or offset of the stimuli, or the selectivity for stimulus velocity. 7. This study provides evidence for the importance of the visual corticotectal projection in the elaboration of the visual receptive-field properties of units in the superior colliculus of the rabbit. In addition, this study shows that the subdivisions of the superior colliculus are differentially affected by the loss of the visual corticotectal projection.
A technique is presented for the nonradiographic assessment of spinal configuration. Its use in the assessment of scoliotic curvatures is discussed in the light of existing radiographic and nonradiographic techniques. The reproducibility of point-encoding measurements relative to a fixed standard is shown to be 98.8 percent. The correlation of pointencoded spinal angles with similar data taken from x-rays is significant at p less than 0.0005. The average standard deviation in the measurement of spinal angles of 10 successive trials on five test subjects is 3.55 degrees +/- 1.95 degrees.
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The pretectal and tectal projections to the thalamic intralaminar nuclei in the cat were studied following horseradish peroxidase injections centered in the central lateral nucleus. Retrogradely labeled neurons were found in both the pretectum and the superior colliculus, ipsilateral and, to a lesser extent, controlateral to the injection site. Labeled pretectal neurons were found throughout all pretectal nuclei; the densest concentrations were in the medial pretectal nucleus, the anterior pretectal nucleus and the nucleus of the posterior commissure. The major source of tectal projections were the small neurons in the stratum griseum intermediate.
The origins of the projections of the superior colliculus to the dorsal lateral geniculate nucleus and to the pulvinar in Dutch-belted rabbits were investigated using horseradish peroxidase (HRP) methods. Following injections of HRP in the dorsal lateral geniculate nucleus, retrogradely labeled neurons were found in the upper two-thirds of the stratum griseum superficiale of the ipsilateral superior colliculus. Most of the labeled somata were spindle-shaped, and their major axes tended to be perpendicular to the surface of the superior colliculus. In contrast, following injections of the pulvinar, labeled neurons were found in the lower third of the ipsilateral stratum griseum superficiale. In these cases, the labeled somata were larger than those labeled following dorsal lateral geniculate injections and were multipolar in shape.
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Specific lymphocyte transformation to three micro-organisms that have been implicated in Crohn's disease was performed. These were Pseudomonas maltophilia, Mycobacterium kansasii and Rotavirus. No significant differences were observed for any of the antigens tested. Simultaneous testing of nonspecific stimulation by PHA also showed no difference between patients and controls. These results do not support an aetiological role for these organisms mediated by a purely cellular mechanism.
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Previous autopsy studies have shown that cerebellar calcification is commoner in Queensland than elsewhere. Computed cranial tomography, which is more sensitive than skull radiography, has confirmed that cerebellar and basal ganglia calcification occur more commonly in patients examined in Queensland than in North America. Although no distinctive neurological syndrome could be demonstrated, the affected patients showed a high incidence of hypertension, hyperuricaemia and raised serum creatinine levels. There is evidence that cerebellar calcification is a marker of previous lead intoxication. Common occurrence of renal impairment in these patients may be due to associated lead nephropathy. Subclinical lead exposure is associated with hyperuricaemia.