On the use of succinylcholine in elk.
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Animal Welfare↗
Biomedical subjects
R M Cooper
Publications and source records attributed to R M Cooper.
Effects of flashing-diffuse light on [2-14C]deoxyglucose uptake in the visual system of the black-hooded rat.
What components of the visual system process diffuse light information? A [2-14C]deoxyglucose (2-DG) autoradiographic analysis revealed that exposure of freely moving rats (wearing light-diffusing masks) to flashing-diffuse light consistently elevated 2-DG uptake in the lateral geniculate nucleus and superior colliculus to levels rivalling those occurring in rats exposed to flashing-gratings. Uptake in visual cortex (area 17) in response to flashing-diffuse light, however, varied as a function of early contour experience, i.e. lower than that produced by darkness in rats reared with high contrast patterns, higher than darkness in rats which had been lid-sutured from the time of eye opening, and falling between these two extremes in 'ordinary' cage-reared rats. The findings point to subcortical mediation of discriminations based on diffuse light information. Cortex might participate in the processing of diffuse light information in the special case of animals lacking contour experience during development.
Animals↗
Metabolic activation of the rat visual system by patterned light and footshock.
Autoradiography with [14C]2-deoxy-D-glucose was used to examine metabolic changes in the visual system of hooded rats exposed to patterned light or to darkness following footshock. Primary retinorecipient structures (superficial layer of the superior colliculus and the dorsal lateral geniculate nucleus) showed a response to light but not to shock. Higher visual sites showed two different shock effects. First, in darkness the intermediate grey layer of the superior colliculus was suppressed by the shock. Second, in the lateral posterior nucleus and primary visual cortex, the footshock led to significant enhancement of the metabolic responses to the patterned light. The findings suggest that footshock-induced arousal has significant modulatory effects on the operations of higher visual centers of behaving rats.
Analysis of Variance↗
Activity-dependent changes in eye influence during monocular blockade: increases in the effects of visual stimulation on 2-DG uptake in the adult rat geniculostriate system.
We examined the effects of loss of monocular retinal activity on 2-deoxyglucose (2-DG) uptake in the adult rat geniculostriate system. Of particular interest was whether the influence of the normally functioning eye changed during long-term contralateral retinal silence. Group 1 rats were subjected to short-term (24 hours) and group 2 rats to long-term (21-90 days) monocular tetrodotoxin (TTX) blockade, and metabolic activity was assessed during exposure to square-wave gratings. Group 1 rats exhibited patterns of cortical glucose utilization commensurate with complete monocular loss of retinal activity: minimal 2-DG uptake in contralateral monocular area 17 and dorsal lateral geniculate nucleus (LGN), and a bilateral depression in the binocular regions; 2-DG uptake was highest in the monocular regions fed by the stimulated normal eye (in both area 17 and the LGN) and these regions appeared unaffected by the monocular blockade. After repeated injections of TTX (group 2), metabolic activity in binocular area 17 and binocular LGN increased bilaterally relative to the metabolically active monocular regions contralateral to the normal eye. Group 3 rats were monocularly TTX-injected for 30 or 60 days, and, 24 hours before 2-DG, all retinal activity was eliminated by means of binocular TTX injections or binocular enucleation. Glucose utilization in the binocular regions of both area 17 and the LGN in these rats was depressed to levels seen in monocular area 17 after complete and recent loss of activity from the contralateral eye, indicating that the metabolic increase which occurred in the binocular regions during long-term monocular retinal blockade was dependent upon the neuronal processing of retinal information from the non-TTX eye. We conclude that, in the adult rat, an activity-dependent, physiologically based shift in ocular influence occurred in the binocular geniculostriate system during long-term monocular retinal inactivation.
Animals↗
[2- 14C]deoxyglucose uptake in rat visual system during flashing-diffuse and flashing-pattern stimulation over a 6 log range of luminance.
The 2-deoxyglucose autoradiographic technique was used to assess the metabolic activity of cortical area 17, the dorsal and ventral lateral geniculate nuclei, the lateral posterior nucleus, and the superior colliculus, during 5-Hz flashing-pattern (montage of black and white square-wave gratings) and flashing-diffuse (eye covered with white mask) stimulation at three intensities over a 6 log range. In area 17 flashing-pattern was found to be equally effective at elevating uptake of the functional label over the photopic-scotopic range of luminance levels tested, whereas flashing-diffuse was ineffective. In subcortical nuclei, however, flashing-diffuse was no less effective than flashing-pattern and uptake of the label correlated positively with intensity level. The results suggest that the subcortical components of the visual system do play an important role in the processing of intensity information and that primary visual cortex does not.
Animals↗
Readability of informed consent forms.
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Communication↗
Identification of a pathogenicity locus in Xanthomonas campestris pv. vesicatoria.
Mutants of a tomato strain of Xanthomonas campestris pv. vesicatoria (XCV), causal agent of bacterial spot of tomato and pepper, were produced using the transposon Tn5 carried in the suicide plasmid pGS9. One prototrophic mutant, M461, was isolated which caused no visible reaction on tomato or pepper, but maintained the wild-type ability to induce a hypersensitive reaction (HR) on tobacco. This mutant showed similar growth characteristics to the wild-type in culture, but growth in planta was reduced. A genomic library of wild-type XCV was constructed in the broad host range cosmid vector pLAFR3. Clone p6AD4 restored pathogenicity to M461 on tomato and the ability to induce a HR on pepper. This clone contained ca. 22 kb of XCV DNA. The insertion in M461 was in a site corresponding to a 1.1 kb EcoRI fragment of p6AD4.
Cloning, Molecular↗
Movement and novelty of a square wave display affect 2-deoxyglucose uptake in the rat visual system.
The [14C]2-deoxy-glucose (2-DG) autoradiographic technique revealed that movement and novelty of a visual display affected rat visual system metabolic activity. Hooded rats were monocularly tested in a surround consisting of patterns of black and white, horizontal and vertical, square wave gratings of different spatial frequencies. For one group this display remained immobile ('stationary' group), and for the other group the display intermittently rotated at 1.5 rpm ('moving' group). Each of these main groups was subdivided such that half had six sessions of prior exposure to the test display ('experienced' group) and half had no prior exposure ('novel' group). The movement groups showed relatively greater 2-DG uptake than the stationary groups in the superior colliculus and in the caudal lateral posterior nucleus, while the novel groups showed greater uptake than the experienced groups in visual cortex.
Animals↗
Effects of prolonged retinal ganglion cell inactivity on superior colliculus glucose metabolism in the mature hooded rat.
Previous work utilizing the 2-deoxyglucose (2-DG) technique demonstrated that denervation, both direct (enucleation) or indirect (retinal receptor destruction, leaving ganglion cells intact), resulted in a depression followed by an increase in glucose metabolism in the superior colliculus (SC) of the mature hooded rat. Both enucleation and receptor loss result in (1) cessation of ganglion cell activity and (2) disruption of connections between visual system neurons. To examine the relative importance of these two factors to the metabolic depression-"recovery" sequence, retinal ganglion cells were silenced without denervation for periods ranging from 24 h to 2 months by means of repeated intraocular tetrodotoxin (TTX) injections. SC metabolic activity fell to levels comparable to those seen after enucleation or receptor damage, but no recovery was detected. A more sensitive within-animal comparison was carried out to detect any small shifts in metabolic activity which might have occurred during retinal blockade; after 1 or 2 months of monocular TTX treatment, either binocular enucleation or binocular TTX injections were performed 24 h before 2-DG, depriving both sides of the SC of retinal input. Metabolic activity was slightly higher in the SC that had received no retinal input for 1 or 2 months, indicating that physiological changes had occurred within the SC during the afferent blockade. A second group of rats was allowed to recover from the effects of long-term TTX for from 1 to 12 days and binocularly exposed to visual stimuli during 2-DG uptake to determine whether damage had resulted from the TTX injections and to assess the time course of the effects of retinal blockade on SC functional activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Neoadjuvant treatment of stages T2 to T4 bladder cancer with cis-platinum, cyclophosphamide and doxorubicin.
In an ongoing phase II study 17 patients with potentially operable transitional cell carcinoma of the bladder (stages T2 to T4, Nx, Mo) have been treated with intravenous cis-platinum (50 mg.per m.2), cyclophosphamide (400 mg.per m.2) and doxorubicin (40 mg.per m.2). They were to receive 3 treatments at 3-week intervals before cystectomy and 2 treatments at 3-week intervals commencing 5 weeks after cystectomy. Of 17 patients 14 (82 per cent) completed all 3 preoperative treatments but only 7 (41 per cent) continued on to complete the entire 5 treatments. In most cases incomplete therapy was due to patient refusal. Toxicity was low as measured by World Health Organization standards. Of the 17 patients 9 (53 per cent) exhibited objective tumor response (pathological downstaging or greater than 50 per cent reduction of tumor volume determined by either computerized tomography scan and/or endoscopic examination. When the determination was made by endoscopy the changes were dramatic and not borderline.) No patient demonstrated a pathological complete response. All 9 of the responders (100 per cent) remain clinically free of disease at a median follow-up of 19 months (range 4 to 30 months). The 8 nonresponders have done poorly with 5 dead of disease, 1 alive with pelvic recurrence and 2 free of disease at 4 and 12 months. These tumor response rates compare favorably with other cis-platinum-based combination regimens. The response to the chemotherapy appears to be an important prognostic indicator. Phase III trials must be conducted to determine whether this neoadjuvant chemotherapy regimen has a significant effect on long-term patient survival.
Aged↗
Metabolic activity in striate and extrastriate cortex in the hooded rat: contralateral and ipsilateral eye input.
The extent of changes in glucose metabolism resulting from ipsilateral and contralateral eye activity in the posterior cortex of the hooded rat was demonstrated by means of the C-14 2-deoxyglucose autoradiographic technique. By stimulating one eye with square wave gratings and eliminating efferent activation from the other by means of enucleation or intraocular TTX injection, differences between ipsilaterally and contralaterally based visual activity in the two hemispheres were maximized. Carbon-14 levels in layer IV of autoradiographs of coronal sections were measured and combined across sections to form right and left matrices of posterior cortex metabolic activity. A difference matrix, formed by subtracting the metabolic activity matrix of cortex contralateral to the stimulated eye from the ipsilateral "depressed" matrix, emphasized those parts of the visual cortex that received monocular visual input. The demarcation of striate cortex by means of cholinesterase stain and the examination of autoradiographs from sections cut tangential to the cortical surface aided in the interpretation of the difference matrices. In striate cortex, differences were maximal in the medial monocular portion, and the lateral or binocular portion was shown to be divided metabolically into a far lateral contralaterally dominant strip along the cortical representation of the vertical meridian, and a more medial region of patches of more or less contralaterally dominant binocular input. Lateral peristriate differences were less than those of striate cortex, and regions of greater and lesser monocular input could be distinguished. We did not detect differences between the two hemispheres in either anterior or medial peristriate areas, thus indicating either completely binocular input (which seems unlikely given the retinotopic organization of these regions), or a greater dependence than in the lateral peristriate on inputs that were not affected by the visual manipulations.
Animals↗
Effects of square-wave gratings and diffuse light on metabolic activity in the rat visual system.
The 2-deoxyglucose (2-DG) technique was used to determine the effects of pattern and diffuse light stimulation on glucose metabolism with hooded rats. Rats placed in a stimulation chamber covered with horizontal and vertical square wave gratings while wearing goggles with one of three pairings of light-occluding, diffusing, or clear lenses, allowed the assessment of the effects of different but simultaneous visual conditions on two sides of the strongly crossed visual system. Eyes covered with occluding lenses were lid-sutured shut 24 h before 2-DG. In order to assess the possibly confounding effects of this lid suture a second group of rats had one eyelid sutured for 24 h, and the other covered with an occluding lens for 20 min, before 2-DG. To further assess the effects of diffuse light a third group of rats was tested in a featureless white box with one eye occluded and the other covered by a diffusing lens. Exposure to pattern stimulation significantly increased metabolic activity in the dorsal lateral geniculate nucleus (LGNd), lateral posterior nucleus (LPN), superior colliculus (SC), and in visual cortex (VC). In contrast, diffuse light only slightly elevated LGNd activity and appeared to have little or no effect in the LPN or VC. Diffuse light, however, was as effective as patterned light in increasing ventral lateral geniculate nucleus activity and strongly suppressed SC activity to a level well below that produced by darkness. Evidently diffuse light, not just patterned light, can significantly govern the operation of central nervous system visual structures.
Animals↗
Metabolic changes in the superior colliculus after retinal receptor loss--neurotrophic interactions in the inactive visual system.
In the mature rat, direct denervation by means of eye enucleation resulted in a temporary metabolic depression followed by "recovery" in primary visual centers as determined by the 2-deoxyglucose technique (4). After unilateral destruction of the retinal receptor layer by means of intense light, the superior colliculus (SC) demonstrated this same depression-recovery process. Because receptor destruction is believed to silence ongoing ganglion cell activity, and because the SC changes occurred whether or not ganglion cells sustained damage, it appeared that direct denervation of colliculus neurons was not necessary to initiate the depression-recovery sequence and that lack of activity or "disuse" was the critical factor. The silencing effect of the receptor destruction was confirmed when tetrodotoxin (TTX) injections into the damaged eye 2 months after damaging light exposure only slightly affected metabolic activity in the recovered colliculus. Binocular TTX injections in unilaterally light-damaged rats after 2 months of recovery resulted in greater depression in the normal colliculus than in the "recovered" colliculus, again suggesting that increases in glucose metabolism over time reflected physiological adjustments in the SC to loss of afferent activity. The strong depression in the SC fed by the normal eye after TTX injection confirmed that tonic retinal afferent activity was important to the metabolic integrity of the SC and that cessation of such activity could lead to at least to depression in the system. In a final group of 2-month recovery animals the light-damaged eye was enucleated. Presumably, if withdrawal of afferent activity is solely responsible for initiating the depression-recovery sequence, the destruction of already silenced retinal ganglion cells would have no effect on the recovered SC. This was not found to be the case. In fact, enucleation reinstated the metabolic depression in the recovered SC and demonstrated that denervation per se resulted in depression of glucose metabolism in postsynaptic neurons. Even in the absence of impulse activity, visual system neurons maintained trophic interactions.
Autoradiography↗
2-Deoxyglucose uptake in the rat visual system following pupil dilation with atropine.
The 2-deoxyglucose (2-DG) technique was used to assess rat visual system metabolic activity after topical eye application of atropine sulfate. After one pupil had been dilated with atropine, the alert and freely moving rats were surrounded by a montage of horizontal and vertical, black and white, square wave gratings of varying spatial frequencies during the 45 min 2-DG uptake period. Autoradiographic analysis of interhemispheric differences in 2-DG uptake revealed that metabolic activity was less in all primary visual structures lying contralateral to, and primarily fed by, the treated eye. The depression was most evident in the dorsal lateral geniculate nucleus, the lateral posterior nucleus and the superior colliculus. These findings urge caution in the use of atropine in studies of rat visual system metabolic activity.
Animals↗
Characterization of cuticle-degrading proteases produced by the entomopathogen Metarhizium anisopliae.
Two chymoelastases and three trypsinlike proteases were separated from culture filtrates of the entomopathogen Metarhizium anisopliae. A chymoelastase (Pr1) (pI 10.3 Mr 25,000) and trypsin (Pr2) (pI 4.42, Mr 28,500) were purified to homogeneity by ammonium sulphate precipitation, isoelectric focusing, and affinity chromatography. Inhibition studies showed that both enzymes possessed essential serine and histidine residues in the active site. Pr1 shows greater activity than Pr2 or mammalian enzymes against locust cuticle and also possesses activity vs elastin. Pr1 shows a broad primary specificity toward amino acids with hydrophobic side groups in synthetic ester and amide substrates. The kinetic properties of Pr1 demonstrate a preference for extended peptide chains with the active site recognising at least five substrate residues. The S5 and S4 subsites show a preference for negatively charged succinyl and hydrophobic acetyl groups, respectively. The S3 and S2 subsites both discriminated in favor of alanine and against proline. Pr2 rapidly hydrolyzed casein and synthetic substrates containing arginine or lysine. It possessed little or no activity vs cuticle, elastin, or synthetic substrates for chymotrypsin and elastase. Specific active site inhibitors confirmed the similarities between Pr2 and trypsin.
Animals↗
Distribution of chymoelastases and trypsin-like enzymes in five species of entomopathogenic deuteromycetes.
Nine isolates of the entomopathogenic deuteromycetes Metarhizium anisopliae, Beauveria bassiana, Verticillium lecanii, Nomuraea rileyi, and Aschersonia aleyrodis produced basic (pI greater than 7.0) chymoelastases that possessed extended binding sites, comprising at least four or five subsites, with preference for hydrophobic residues at the primary binding site. Most isolates also produced additional acidic enzymes with similar specificities against ester and amide substrates but which lacked activity against elastin. Both acidic and basic enzymes degraded high protein azure or locust cuticle and, as shown by inhibition studies, possessed essential serine and histidine residues in the active site. In spite of similarities in catalytic properties antibodies generated against a Metarhizium chymoelastase cross-reacted only with enzymes from two (out of four) Metarhizium isolates; enzymes from all other isolates did not cross-react. Two isolates of Metarhizium produced a third class of protease which degraded Bz-AA-AA-Arg-NA substrates (AA, various amino acids) and hide protein azure. Analogous peptidases were produced by other isolates but they were specific for Bz-Phe-Val-Arg-NA and showed less sensitivity to trypsin inhibitors. The possible significance to pathology of the presence of diverse yet similar protease forms in five genera of entomopathogens is discussed.
Amides↗
Reversal of 2-deoxyglucose uptake pattern across rat superior colliculus layers during recovery from visual cortex ablation.
The 2-deoxy-D-[14C]glucose autoradiographic technique was used to assess metabolic activity across stratum griseum superficiale, stratum opticum, and stratum griseum mediale of the superior colliculus, at intervals of 1 to 90 days after a unilateral visual cortex lesion. Initially, glucose metabolism ipsilateral to the lesion was more depressed in stratum griseum mediale than in superficiale, but beginning at about 14 days postlesion this layer pattern reversed. The rise in mediale metabolic activity correlated in time with a decline in generalized cortical depression. On the basis of anatomic connections, we concluded that the generalized cortical depression had disrupted input to stratum griseum mediale from cortical areas other than area 17, and that with recovery of cortical metabolic activity, stratum griseum mediale metabolic activity increased to nearly normal.
Animals↗
1986 ASCN Public Policy Forum--disease specific claims on foods: possibilities and problems. Health claims on foods--reflections on the food/drug distinction and on the law of misbranding.
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Advertising↗