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Abstract
Postoperative patients differ in their response to pain and opioids. It is therefore important that nurses offer other options as adjuvants to medication. Relaxation and music may reduce pain by interrupting the postoperative cycle of pain, muscle tension and sympathetic activity. This review summarizes and critiques studies on the effectiveness of relaxation and music use during postoperative pain. Relaxation and music were effective in reducing affective and observed pain in the majority of studies, but they were less often effective in reducing sensory pain or opioid intake. However, the between-study differences in surgical procedures, experimental techniques, activities during testing, measurement of pain, and amount of practice make comparisons difficult. Furthermore, within studies, the problems of inadequate sample size, lack of random assignment, no assurance of pretest equivalence, delayed post-test administration and no control for opiates at the time of testing reduces the validity of the studies' conclusions. Randomized controlled studies of the types of relaxation and music that are most helpful to postoperative patients should be explored in various contexts.
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102
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Good M. Targeted deletion of neuronal nitric oxide: a step closer to understanding its functional significance? Trends Neurosci 1996; 19:83-4. [PMID: 9054058 DOI: 10.1016/s0166-2236(96)80031-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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103
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Good M, Moore SM. Clinical practice guidelines as a new source of middle-range theory: focus on acute pain. Nurs Outlook 1996; 44:74-9. [PMID: 8722673 DOI: 10.1016/s0029-6554(96)80053-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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104
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Good M. Complementary modalities/Part 2. Relaxation techniques for surgical patients. Am J Nurs 1995; 95:38-42; quiz 43. [PMID: 7537450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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105
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Good M. A comparison of the effects of jaw relaxation and music on postoperative pain. Nurs Res 1995; 44:52-7. [PMID: 7862546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This experimental study compared the effects of jaw relaxation and music, individually and combined, on sensory and affective pain following surgery. Abdominal surgical patients (N = 84) were randomly assigned to four groups: relaxation, music, a combination of relaxation and music, and control. Interventions were taught preoperatively and used by subjects during the first ambulation after surgery. Indicators of the sensory component of pain were sensation and 24-hour narcotic intake. Indicators of the affective component of pain were distress and anxiety of pain. With preambulatory sensation, distress, narcotic intake, and preoperative anxiety as covariates, the four groups were compared using orthogonal a priori contrasts and analysis of covariance. The interventions were neither effective nor significantly different from one another during ambulation. However, after keeping the taped interventions for 2 postoperative days, 89% of experimental subjects reported them helpful for sensation and distress of pain.
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106
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Good M, Macphail EM. The avian hippocampus and short-term memory for spatial and non-spatial information. THE QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY. B, COMPARATIVE AND PHYSIOLOGICAL PSYCHOLOGY 1994; 47:293-317. [PMID: 7972890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three experiments investigated the role of the pigeon hippocampal formation (the hippocampus and area-parahippocampalis) in short-term memory for non-spatial and spatial information. The acquisition of delayed matching-to-sample and the short-term retention of non-spatial visual information, using a small set of sample stimuli, were unaffected by aspiration lesions of the hippocampus or the neostriatum (Experiment 1). Similarly, acquisition and short-term retention of non-spatial information using a successive, trial-unique, delayed non-matching-to-sample procedure were unaffected by hippocampal damage; the same birds had, however, displayed a profound autoshaping impairment (Experiment 2). Acquisition of a spatial delayed matching-to-sample task was unimpaired by hippocampal damage. However, lesioned animals were impaired following the introduction of retention intervals on this procedure (Experiment 3). The correspondence between the behavioural effects of hippocampal lesions in birds and mammals on short-term memory is discussed, and the implications of these results for avian hippocampal function are considered.
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107
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Good M, Macphail EM. Hippocampal lesions in pigeons (Columba livia) disrupt reinforced preexposure but not overshadowing or blocking. THE QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY. B, COMPARATIVE AND PHYSIOLOGICAL PSYCHOLOGY 1994; 47:263-91. [PMID: 7972889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Three experiments examined the effects of hippocampal lesions in pigeons on overshadowing, blocking, and a latent inhibition treatment (non-differential reinforced preexposure) using a simultaneous visual discrimination paradigm. The results showed that hippocampal damage did not influence overshadowing (Experiment 1) or blocking (Experiment 2) but did attenuate the retardation in conditioning associated with non-differential reinforced preexposure to to-be-discriminated stimuli (Experiment 3). Hippocampal birds also displayed impaired autoshaping (Experiments 1, 2, and 3). The correspondence between the behavioural effects of avian and mammalian hippocampal lesions is discussed, and the implications of the present pattern of results for avian hippocampal function are considered.
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108
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Kuenzle C, Baenziger O, Martin E, Thun-Hohenstein L, Steinlin M, Good M, Fanconi S, Boltshauser E, Largo RH. Prognostic value of early MR imaging in term infants with severe perinatal asphyxia. Neuropediatrics 1994; 25:191-200. [PMID: 7824091 DOI: 10.1055/s-2008-1073021] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The prognostic significance of magnetic resonance imaging (MRI) in the neonatal period was studied prospectively in 43 term infants with perinatal asphyxia. MRI was performed between 1 and 14 days after birth with a high field system (2.35 Tesla). Neurodevelopmental outcome was assessed by a standardized neurological examination and the Griffiths developmental test at a mean age of 18.9 months. The predictive value of the various MRI patterns was as follows: Severe diffuse brain injury (pattern AII+III; n = 7) and lesions of thalamus and basal ganglia (pattern C; n = 5) were strongly associated with poor outcome and greatly reduced head growth. Mild diffuse brain injury (pattern AI; n = 7), parasagittal lesions (B; n = 7), periventricular hyperintensity (D; n = 2), focal brain necrosis and hemorrhage (E; n = 3) and periventricular hypointense stripes (on T2-weighted images; F; n = 3) led in one third of the infants to minor neurological disturbances and mild developmental delay. Infants with normal MRI findings (G; n = 9) developed normally with the exception of one infant who was mildly delayed at 18 months. The results indicate that MRI examination during the first two weeks of life is of prognostic significance in term infants suffering from perinatal asphyxia. Severe hypoxic-ischemic brain lesions were associated highly significantly with poor neuro-developmental outcome, whereas infants with inconspicuous MRI developed normally.
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Steinlin M, Good M, Martin E, Bänziger O, Largo RH, Boltshauser E. Congenital hemiplegia: morphology of cerebral lesions and pathogenetic aspects from MRI. Neuropediatrics 1993; 24:224-9. [PMID: 8232782 DOI: 10.1055/s-2008-1071545] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have analyzed the MRI findings from the brains of 33 children with congenital hemiplegia. Referral of these children to our hospital was either because of neurological problems or a history of complicated birth. According to maturation-dependent pathophysiological mechanisms we have classified the lesions into the following five groups: 1. malformations/prenatal encephalo-clastic lesions, 2. periventricular leukomalacia or atrophy, 3. diencephalic lesions, 4. subcortical and cortical lesions, and 5. normal findings. Combination of lesions was not uncommon. The neuroradiologically most prominent and most expanded lesions determined the classification to the different groups. We detected malformations/encephalo-clastic lesions (Group 1) in 5 children; one of these children also presented additional lesions of Groups 2 and 3. Six children displayed periventricular leukomalacia (Group 2), and in one child in combination with diencephalic and subcortical lesions. Ten children exhibited diencephalic lesions (Group 3), in one case combined with periventricular leukomalacia. The MRI of seven children showed subcortical/cortical lesions (Group 4), in four cases extending into diencephalic structures. Two children had a combination of evenly matched periventricular, diencephalic and subcortical/cortical lesions, where it was impossible to define a principal lesion. Three children had normal MRI findings. Significantly, 8 of 33 children had bilateral lesions although presenting with hemiplegia. The large proportion of diencephalic lesions, not described in similar CT studies, and the small number of normal MRI findings show the value of MRI in evaluation of congenital hemiplegia. The ability to correlate, to some extent, neuroradiological findings of damage to developmental stage affords the conclusion that at least a third of the children in our series with congenital hemiplegia suffered prenatal damage.
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110
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Hartmannsgruber M, Good M, Carovano R, Lampotang S, Gravenstein JS. [Anesthesia simulators and training devices]. Anaesthesist 1993; 42:462-9. [PMID: 8363031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Simulators and training devices are used extensively by educators in 'high-tech' occupations, especially those requiring an understanding of complex systems and co-ordinated psychomotor skills. Because of advances in computer technology, anaesthetised patients can now be realistically simulated. This paper describes several training devices and a simulator currently being employed in the training of anaesthesia personnel at the University of Florida. This Gainesville Anesthesia Simulator (GAS) comprises a patient mannequin, anaesthesia gas machine, and a full set of normally operating monitoring instruments. The patient can spontaneously breathe, has audible heart and breath sounds, and palpable pulses. The mannequin contains a sophisticated lung model that consumes and eliminates gas according to physiological principles. Interconnected computers controlling the physical signs of the mannequin enable the presentation of a multitude of clinical signs. In addition, the anaesthesia machine, which is functionally intact, has hidden fault activators to challenge the user to correct equipment malfunctions. Concealed sensors monitor the users' actions and responses. A robust data acquisition and control system and a user-friendly scripting language for programming simulation scenarios are key features of GAS and make this system applicable for the training of both the beginning resident and the experienced practitioner. GAS enhances clinical education in anaesthesia by providing a non-threatening environment that fosters learning by doing. Exercises with the simulator are supported by sessions on a number of training devices. These present theoretical and practical interactive courses on the anaesthesia machine and on monitors. An extensive system, for example, introduces the student to the physics and clinical application of transoesophageal echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)
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111
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Honey RC, Good M. Selective hippocampal lesions abolish the contextual specificity of latent inhibition and conditioning. Behav Neurosci 1993. [PMID: 8447955 DOI: 10.1037//0735-7044.107.1.23] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The contextual specificity of the conditioned response (CR) and latent inhibition (LI) was examined in rats with selective hippocampal lesions. Acquisition of the CR to a novel conditioned stimulus (CS) was equally rapid in control and hippocampal rats (Experiments 1 and 2), and CS preexposure disrupted acquisition, (i.e., produced LI) to an equal extent in both groups (Experiment 2). In control subjects, however, the CR established in one context transferred incompletely to a second context (Experiment 1), and LI was attenuated when CS preexposure and conditioning occurred in different contexts (Experiment 3). This context specificity of the CR and LI was not apparent in hippocampal rats--the CR and LI transferred readily from one context to another. In addition, hippocampal rats were impaired in a spatial learning task (Experiment 2) but were unimpaired in learning a Pavlovian contextual discrimination (Experiment 3). These results suggest that a common contextual retrieval process underlies the contextual dependence of the CR and of LI and that this process is mediated by the hippocampus.
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112
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Macphail EM, Reilly S, Good M. Lateral hyperstriatal lesions disrupt simultaneous but not successive conditional discrimination learning of pigeons (Columba livia). Behav Neurosci 1993; 107:289-98. [PMID: 8484894 DOI: 10.1037/0735-7044.107.2.289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In 2 experiments we explored the effects of lateral versus medial laminar lesions of the hyperstriatum in pigeons (Columba livia); medical lesions were largely confined to the hyperstriatum accessorium, and lateral lesions to the hyperstriatum dorsale and hyperstriatum ventrale. In Experiment 1, lateral, but not medial, lesions disrupted acquisition of a simultaneous conditional discrimination; both medial and lateral lesions disrupted reversal of the discrimination. The reversal deficits of the medial and lateral groups were quantitatively similar, and both groups showed exaggerated positional responding. In Experiment 2, neither medial nor lateral lesions disrupted acquisition of a successive conditional discrimination. We conclude that lateral hyperstriatal damage does not obtain a general disruption of conditional learning; we speculate that the lateral hyperstriatum may play a critical role in configural learning.
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113
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Honey RC, Good M. Selective hippocampal lesions abolish the contextual specificity of latent inhibition and conditioning. Behav Neurosci 1993; 107:23-33. [PMID: 8447955 DOI: 10.1037/0735-7044.107.1.23] [Citation(s) in RCA: 216] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The contextual specificity of the conditioned response (CR) and latent inhibition (LI) was examined in rats with selective hippocampal lesions. Acquisition of the CR to a novel conditioned stimulus (CS) was equally rapid in control and hippocampal rats (Experiments 1 and 2), and CS preexposure disrupted acquisition, (i.e., produced LI) to an equal extent in both groups (Experiment 2). In control subjects, however, the CR established in one context transferred incompletely to a second context (Experiment 1), and LI was attenuated when CS preexposure and conditioning occurred in different contexts (Experiment 3). This context specificity of the CR and LI was not apparent in hippocampal rats--the CR and LI transferred readily from one context to another. In addition, hippocampal rats were impaired in a spatial learning task (Experiment 2) but were unimpaired in learning a Pavlovian contextual discrimination (Experiment 3). These results suggest that a common contextual retrieval process underlies the contextual dependence of the CR and of LI and that this process is mediated by the hippocampus.
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114
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Baenziger O, Martin E, Steinlin M, Good M, Largo R, Burger R, Fanconi S, Duc G, Buchli R, Rumpel H. Early pattern recognition in severe perinatal asphyxia: a prospective MRI study. Neuroradiology 1993; 35:437-42. [PMID: 8377915 DOI: 10.1007/bf00602824] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
On the basis of MRI examinations in 88 neonates and infants with perinatal asphyxia, we defined 6 different patterns on T2-weighted images: pattern A--scattered hyperintensity of both hemispheres of the telencephalon with blurred border zones between cortex and white matter, indicating diffuse brain injury; pattern B--parasagittal hyperintensity extending into the corona radiata, corresponding to the watershed zones; pattern C--hyper- and hypointense lesions in thalamus and basal ganglia, which relate to haemorrhagic necrosis or iron deposition in these areas; pattern D--periventricular hyperintensity, mainly along the lateral ventricles, i.e. periventricular leukomalacia (PVL), originating from the matrix zone; pattern E--small multifocal lesions varying from hyper--to hypointense, interpreted as necrosis and haemorrhage; pattern F--periventricular centrifugal hypointense stripes in the centrum semiovale and deep white matter of the frontal and occipital lobes. Contrast was effectively inverted on T1-weighted images. Patterns A, B and C were found in 17%, 25% and 37% of patients, and patterns D, E and F in 19%, 17% and 35%, respectively. In 49 patients a combination of patterns was observed, but 30% of the initial images were normal. At follow-up, persistent abnormalities were seen in all children with patterns A and D, but in only 52% of those with pattern C. Myelination was retarded most often in patients with diffuse brain injury and PVL (patterns A and D).
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115
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Abstract
The role of the hippocampus in associative learning was investigated in 3 experiments with rats as subjects. Hippocampal rats were impaired in the acquisition of conditioned responding both when food was signaled by the insertion of a lever (Experiment 1) and when the presentation of auditory or visual events served as the conditioned stimuli (Experiment 2). Experiment 2 also evaluated the suggestion that deficits in the acquisition of conditioned responding reflect the failure of hippocampal subjects to use contextual cues to retrieve associative information. This experiment showed that hippocampal rats were impaired in learning that a given stimulus was reinforced in Context A but nonreinforced in Context B. Experiment 3 demonstrated that hippocampal rats were unimpaired in learning a simple Pavlovian contextual discrimination. This pattern of results suggests that the hippocampus is involved in a higher order contextual retrieval process.
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116
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Good M, Hollenstein R, Vasák M. Metal selectivity of clusters in rabbit liver metallothionein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 197:655-9. [PMID: 1851481 DOI: 10.1111/j.1432-1033.1991.tb15955.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In mammalian metallothioneins the metals are organized in two adamantane-type clusters with three and four metal ions which are tetrahedrally coordinated by thiolate ligands. The metal selectivity of the metal-thiolate clusters in rabbit liver metallothionein has been studied by offering two ions, i.e. Co(II)/Cd(II), Zn(II)/Cd(II) or Co(II)/Zn(II), to the metal-free protein. The heterogeneous metal complexes thus formed were characterized by electronic absorption, magnetic circular dichroism. 113Cd-NMR and EPR spectroscopy. In the case of Co/Cd-metallothionein, homometallic cluster occupation occurs, with the Cd(II) ions bound exclusively to the four-metal cluster. In contrast, heterometallic clusters were formed for both Zn/Cd- and Co/Zn-metallothionein. Based on evidence from corresponding inorganic structures of adamantane metal-thiolate cages, it is suggested that the major factor governing the cluster type is the protein structure perturbation due to the cluster volume variations. Thus, while metal thiolate affinities are important in the folding process, size-match selectivity is the dominant factor in the metal-loaded protein.
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117
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Abstract
The role of the hippocampus in associative learning was investigated in 3 experiments with rats as subjects. Hippocampal rats were impaired in the acquisition of conditioned responding both when food was signaled by the insertion of a lever (Experiment 1) and when the presentation of auditory or visual events served as the conditioned stimuli (Experiment 2). Experiment 2 also evaluated the suggestion that deficits in the acquisition of conditioned responding reflect the failure of hippocampal subjects to use contextual cues to retrieve associative information. This experiment showed that hippocampal rats were impaired in learning that a given stimulus was reinforced in Context A but nonreinforced in Context B. Experiment 3 demonstrated that hippocampal rats were unimpaired in learning a simple Pavlovian contextual discrimination. This pattern of results suggests that the hippocampus is involved in a higher order contextual retrieval process.
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118
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Bailey BK, McGrady AV, Good M. Management of a patient with insulin-dependent diabetes mellitus learning biofeedback-assisted relaxation. DIABETES EDUCATOR 1990; 16:201-4. [PMID: 2185005 DOI: 10.1177/014572179001600310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Psychological stress can have profound disruptive effects upon glycemic control in individuals with diabetes. Presented here is a case study in which biofeedback-assisted relaxation techniques were used to help a young woman with a 10-year history of insulin-dependent diabetes mellitus to more effectively manage stress, thereby improving glycemic control. Hypoglycemia is a frequently encountered problem with this technique, so the patient was taught to identify causes of hypoglycemic episodes and to take action to prevent their occurrence. The team approach of a diabetes nurse educator working in conjunction with a biofeedback therapist was vital to the success of this program.
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119
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Bailey BK, Good M, McGrady A. Clinical observations on behavioral treatment of a patient with insulin-dependent diabetes mellitus. BIOFEEDBACK AND SELF-REGULATION 1990; 15:7-13. [PMID: 2361148 DOI: 10.1007/bf00999073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This report uses a single case format to describe clinical observations on the use of biofeedback-assisted relaxation in Type I insulin-dependent diabetes mellitus. It is suggested that treatment based on relaxation training may be utilized in diabetics provided that certain conditions are met and that the relaxation procedure is modified to conform to the special requirements of persons taking insulin. Since both client characteristics and type of training protocol can markedly affect outcome, it may be especially important to tailor the training protocol for each insulin-dependent diabetic patient, based on careful and continuous monitoring of treatment effects.
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120
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Abstract
The performance of pigeons with hippocampal lesions was compared with that of unoperated and neostriatal-lesioned control Ss in 3 experiments. In Experiment 1, hippocampal-lesioned birds were retarded in the acquisition and the maintenance levels of autoshaped responding. However, the deficit was attenuated following the addition of a response contingency to the autoshaping schedule. In Experiment 2, the hippocampal-lesioned birds showed impaired performance on a differential reinforcement of low rates of responding schedule. From the high levels of responding in Experiment 2, underresponding was observed in hippocampal-lesioned birds relative to control Ss on return to the autoshaping schedule in Experiment 3. Results are interpreted in terms of impaired classical conditioning in hippocampal-lesioned birds.
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121
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Abstract
The performance of pigeons with hippocampal lesions was compared with that of unoperated and neostriatal-lesioned control Ss in 3 experiments. In Experiment 1, hippocampal-lesioned birds were retarded in the acquisition and the maintenance levels of autoshaped responding. However, the deficit was attenuated following the addition of a response contingency to the autoshaping schedule. In Experiment 2, the hippocampal-lesioned birds showed impaired performance on a differential reinforcement of low rates of responding schedule. From the high levels of responding in Experiment 2, underresponding was observed in hippocampal-lesioned birds relative to control Ss on return to the autoshaping schedule in Experiment 3. Results are interpreted in terms of impaired classical conditioning in hippocampal-lesioned birds.
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122
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Good M, Hollenstein R, Sadler PJ, Vasák M. 113Cd NMR studies on metal-thiolate cluster formation in rabbit Cd(II)-metallothionein: evidence for a pH dependence. Biochemistry 1988; 27:7163-6. [PMID: 3196709 DOI: 10.1021/bi00418a074] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The formation of two metal-thiolate clusters in rabbit liver metallothionein 2 (MT) has been examined by 113Cd NMR spectroscopy at pH 7.2 and 8.6. The chemical shifts of the 113Cd resonances developing in the course of apoMT titration with 113Cd(II) ions have been compared with those of fully metal occupied 113Cd7-MT. At pH 7.2 and at low metal occupancy (less than 4), a cooperative formation of the four-metal cluster (cluster A) occurs. Further addition of 113Cd(II) ions generates all the resonances of the three-metal cluster (cluster B) in succession, suggesting cooperative metal binding to this cluster also. In contrast, similar studies at pH 8.6, at low metal occupancy (less than 4), reveal a broad NMR signal centered at 688 ppm. This observation indicates that an entirely different protein structure exists. When exactly 4 equiv of 113Cd(II) are bound to apoMT, the 113Cd NMR spectrum changes to the characteristic spectrum of cluster A. Further addition of 113Cd(II) ions again leads to the cooperative formation of cluster B. These results stress the determining role of the cluster A domain on the overall protein fold. The observed pH dependence of the cluster formation in MT can be rationalized by the different degree of deprotonation of the cysteine residues (pKa approximately 8.9), i.e., by the difference in the Gibbs free energy required to bind Cd(II) ions to the thiolate ligands at both pH values.
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123
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Overnell J, Good M, Vasàk M. Spectroscopic studies on cadmium (II)- and cobalt(II)-substituted metallothionein from the crab Cancer pagurus. Evidence for one additional low-affinity metal-binding site. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 172:171-7. [PMID: 2831057 DOI: 10.1111/j.1432-1033.1988.tb13869.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The binding of diamagnetic Cd(II) and paramagnetic Co(II) ions to the metal-free form of crab, Cancer pagurus, metallothionein (MT) was studied by various spectroscopic techniques. Both reconstituted and native Cd(II)-MT containing 6 mol Cd(II)/mol protein display electronic absorption, circular dichroism (CD) and magnetic circular dichroism (MCD) spectra which were indistinguishable. The stoichiometric replacement of Cd(II) ions in native Cd(II)6-MT by paramagnetic Co(II) ions enabled the geometry of the metal-binding sites to be probed. The electronic absorption and MCD spectra of Co(II)6-MT revealed features characteristic of distorted tetrahedral tetrathiolate Co(II) coordination for all six metal-binding sites. The stepwise incorporation of Cd(II) and Co(II) ions into this protein was monitored by electronic absorption and CD, and by electronic absorption and EPR spectroscopy, respectively. The results indicate that the metal-thiolate cluster structure is generated when more than four metal ions are bound. Below this titration point separate tetrahedral tetrathiolate complexes exist. This suggests that the cluster formation occurs in a two-step process. Furthermore, the spectroscopic features in both Cd(II)- and Co(II)-metal derivatives above the full metal occupancy of six suggest the existence of one additional metal-binding site. The subsequent loss of one Cd(II) ion from crab Cancer Cd(II)7-MT in the gel filtration studies demonstrate the low metal-binding affinity of the latter site. While the spectroscopic properties indicate an exclusively tetrahedral type of metal-thiolate sulfur coordination for the binding of the first six metal ions, they suggest that the seventh metal ion is coordinated in a different fashion.
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Ding X, Bill E, Good M, Trautwein AX, Vasák M. Mössbauer studies on the metal-thiolate cluster formation in Fe(II)-metallothionein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 171:711-4. [PMID: 3345754 DOI: 10.1111/j.1432-1033.1988.tb13843.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The stepwise 57Fe(II)-thiolate cluster formation in rabbit liver metallothionein-2 (MT) has been followed at pH 8.5 using Mössbauer spectroscopy. The zero-field spectra recorded at 4.2 K exhibit at all stages of filling one virtually identical single quadrupole splitting delta EQ and isomer shift delta as found for reduced rubredoxin (Rdred) or the model compound [Fe(II)(SPh)4]2-, thus indicating an Fe(II)-tetrathiolate coordination. A similar conclusion was reached also in previous electronic absorption studies [M. Good and M. Vasák (1986) Biochemistry 25,8353--8356]. The Mössbauer spectra obtained in the presence of a magnetic field were analyzed on the basis of a spin-Hamiltonian formalism resulting in Mössbauer parameters similar to those for Rdred and the inorganic model compound [Fe(II)(SPh)4]2-. The identity of the Mössbauer parameters of partially and fully metal-occupied MT suggests that a comparable distortion of the metal binding sites must exist. Simulation of the spectra revealed that the Fe(II) ions in the partially metal-occupied 57Fe(II)4-MT form appear to be magnetically isolated, whereas in the fully metal-saturated 57Fe(II)7-MT form a ratio of 3:4 of paramagnetic to diamagnetic subspectra was obtained. The latter result suggests the existence of three isolated metal binding sites and a metal-thiolate cluster containing four metal ions. In the light of structure determinations of MT containing Zn(II) and/or Cd(II) [W. Braun et al. (1986) J. Mol. Biol. 187, 125-129, and W. F. Furrey et al. (1986) Science (Wash. DC) 231, 704-710], which revealed two metal-thiolate clusters containing three and four metal ions, respectively, and involving all 20 cysteine residues in metal binding, the appearance of Mössbauer parameters characteristic of three isolated Fe(II) sites in 57Fe(II)7-MT is peculiar and deserves further studies. It is concluded, moreover, that the four-metal cluster is diamagnetic with the four Fe(II) ions being antiferromagnetically coupled. The appearance of magnetic coupling above four Fe(II) equivalents bound to apoMT indicates that the cluster formation occurs in a two-step process.
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125
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Reilly S, Good M. Enhanced DRL and impaired forced-choice alternation performance following hippocampal lesions in the pigeon. Behav Brain Res 1987; 26:185-97. [PMID: 3426789 DOI: 10.1016/0166-4328(87)90166-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In four experiments, pigeons with bilateral lesions of the hippocampus were compared to unoperated control birds and operated control subjects that received bilateral lesions of the neostriatum on tasks sensitive to hippocampal damage in mammals. Consistent with the mammalian literature, hippocampal birds were impaired on forced-choice alternation in the T-maze, although they were unimpaired on spatial alternation and reversal learning in an operant chamber. Furthermore, in contrast to hippocampal mammals, hippocampal pigeons showed enhanced performance on a differential reinforcement of low-rates of responding schedule of reinforcement. The results are discussed with respect to a behavioural homology between the avian and mammalian hippocampal formations.
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