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Biomedical subjects

R G Robinson

Publications and source records attributed to R G Robinson.

At least 235 records · Page 13Linked to original sources
PubMed1985

Asymmetrical effect of unilateral cortical lesions and amphetamine on DRL-20: a time-loss analysis.

Male Sprague Dawley rats received unilateral 1.5 mm diameter focal suction lesions of either the left or right orbito-frontal cortex and were tested for response to 6 doses of amphetamine sulfate ranging from 0.5 to 1.5 mg/kg on a DRL-20 schedule of reinforcement. Right hemispheric lesion animals obtained a greater number of control reinforcements and were more sensitive to amphetamine's disruptive effects, showing a greater dose-related decrease in water rewards obtained than left lesion animals. An analysis method is introduced which combines the interactive effects of premature responses and their IRT value in a way that relates directly to reinforcement attainment. Calculated total session time made unavailable for reinforcement due to premature responding, correlated negatively (r = -.942) with the number of reinforcements obtained.

Amphetamine↗
PubMed1985

Intracortical 5,7-dihydroxytryptamine depletes brain serotonin concentrations without affecting spontaneous activity.

Microinjections of either 2 or 4 micrograms of the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) were made into either the right or left frontal cortex of male rats pretreated with desmethylimipramine. Although both the 2 and 4 micrograms doses produced significant depletions of serotonin concentrations in the cortex and median raphe, neither dose produced a significant increase in spontaneous activity. This is in contrast to our findings with the noradrenergic neurotoxins, 6-hydroxydopamine and DSP-4, which produced hyperactivity following right but not left hemisphere injections. These findings do not rule out the involvement of 5-HT in the asymmetrically elicited hyperactivity but they do suggest some transmitter and neural pathway specificity to the lateralized response to cortical injury.

5,7-Dihydroxytryptamine↗
PubMed1985

A two-year longitudinal study of poststroke mood disorders. In-hospital prognostic factors associated with six-month outcome.

In a prospective study of mood disorders in stroke patients, variables obtained during the acute hospitalization were examined for their relationship to outcome at either 3- or 6-month follow-up. Distance of the lesion on computerized axial tomography scan from the frontal pole in patients with left anterior infarcts was significantly associated with severity of depression at 3 and 6 months poststroke. In addition, intellectual and functional physical impairment in-hospital were significantly correlated with severity of depression and social functioning scores at 3 and 6 months poststroke. Thus, patients who develop depression during the first 6 months poststroke may be responding to the severity of their impairment whereas the patients who develop depressions during the acute poststroke period may have a neuroanatomical and neurophysiological basis for their depression. Although other explanations might be proposed, the dynamic nature of the relationship between depression and associated variables during the first 6 months poststroke indicates that etiology of poststroke depression may be different depending upon the time of onset of the depression after brain injury.

Acute Disease↗
PubMed1985

Prolongation of gastric emptying by aerosolized atropine.

Aerosolized atropine causes anticholinergic side effects. We evaluated gastroparesis, a previously unreported side effect of inhaled atropine, in a double-blind, placebo-controlled, crossover study. Six young asthmatics received atropine (0.05 mg/kg) or placebo at 4-h intervals for 3 dosages, on 2 separate days at least 1 wk apart. Subjective complaints, pulse, visual accommodation, and citric-acid-stimulated salivary flow were recorded 30 min after each dose on each study day. A radionuclide (99mTc) study of gastric emptying time was done 30 min after the final dose on each study day. Atropine prolonged mean gastric half emptying time (112 +/- 59 min) compared with placebo (65 +/- 34 min) (p less than 0.05). However, gastric emptying after atropine was in the abnormal range in only 2 patients. Stimulated salivary flow decreased after atropine (1.97 +/- 1.7 g saliva) compared with flow after placebo (4.1 +/- 1.2 g) (p less than 0.05). No changes in visual accommodation or pulse rate were seen. Dry mouth and decreased salivation correlated with delayed gastric emptying (r = 0.76, p less than 0.05). Anticholinergic side effects of aerosolized atropine include prolonged gastric emptying in some patients. Gastroparesis after inhaled atropine is suggested by the symptom of dry mouth.

Adult↗
PubMed1985

Mood disorders in left-handed stroke patients.

Thirty left-handed patients hospitalized for stroke were examined for mood disorders. Patients with left hemisphere lesions and nondominant hand impairments had significantly higher depression scores and more depressive diagnoses than patients with right hemisphere lesions and dominant hand impairments. Major depression was strongly associated with left anterior brain injury, and depression severity was significantly correlated with proximity of the lesion on CAT scan to the left frontal pole. These findings are almost identical to previously reported results from right-handed patients and suggest that cerebral lateralization of poststroke mood disorders may be independent of cerebral motor dominance and language dominance.

Aphasia↗
PubMed1985

The dexamethasone suppression test and mood following stroke.

Dexamethasone suppression tests (DSTs) were given to 65 acute and chronic stroke patients. For patients who had had a stroke less than 1 year earlier, nonsuppression on the DST was significantly associated with the presence of poststroke depression. The authors, who used the DSM-III symptom criteria for major depression, found that DST sensitivity was 67% but specificity was only 70%. False positive tests in the stroke patients seemed related to large lesion volume. The DST, although of limited clinical utility in this population because of false positive tests, may help define more homogeneous subtypes of poststroke depression for research.

Aged↗
PubMed1985

Phonologic agraphia in a left-handed patient after a right-hemisphere lesion.

Oral and written spelling were evaluated in a left-handed patient with a right-hemisphere infarct and right-hemisphere language representation. Spelling was intact for different classes of words, but there was severe difficulty in both oral and written spelling of nonwords. This pattern was consistent with phonologic agraphia. There was selective disruption of the segmentation component, with intact phoneme-to-grapheme conversion supporting the Roeltgen and Heilman hypothesis of two-system spelling after lesions in the left supramarginal gyrus. This is the first case of phonologic agraphia after right supramarginal gyrus damage in a left-handed patient.

Adult↗
PubMed1985

Parkinson's disease: a comparison of mesulergine and bromocriptine.

Previous studies with mesulergine (CU 32-085) demonstrated safety and efficacy in short-term observations of patients with Parkinson's disease. We compared mesulergine with bromocriptine in 20 patients with Parkinson's disease. Eighteen patients completed the randomized, double-blind, crossover study. Clinical assessments employed the UBC scale and "Mini-Mental State" examination; neurophysiologic measurements were undertaken on wrist rigidity and speed and accuracy of hand movement, and toxicity screening tests were compared. There were no significant differences between the effects of mesulergine (mean dosage, 27.4 mg/d) and bromocriptine (mean dosage, 40.8 mg/d).

Adult↗
PubMed1985

An open study evaluating the reactogenicity and immunogenicity of a DTP vaccine containing an acellular pertussis component in four to six year old children.

Acellular pertussis vaccines have been used for mass immunization of children in Japan since the fall of 1981, but until recently they have not been evaluated in the United States. We report a trial with a DTP vaccine containing an acellular pertussis component in 36 four to six year old children who had previously received four doses of United States DTP licensed vaccine with a whole cell pertussis vaccine component. The study vaccine contained diphtheria and tetanus toxoids and 300 HA units of Takeda acellular pertussis component. The principle immunizing antigens in the pertussis component of the vaccine were lymphocytosis promoting factor (LPF) and filamentous hemagglutinin (FHA). Local and systemic reactions were monitored during the first 48 hours after vaccination, and pre-immunization and one month post-immunization serum specimens were obtained for antibody assay. The following reaction rates were noted: redness 50%, tenderness 50%, swelling 41%, fever (greater than or equal to 38 degrees C) 3%, drowsiness 17%, fretfulness 14%, anorexia 11%, and vomiting 6%. Pertussis antibody values (preimmunization/postimmunization) were as follows: agglutinin GMT, 1:21/1:100; FHA mean ELISA u, 28 +/- 6/greater than or equal to 229 +/- 47; LPF mean ELISA u, 176 +/- 59/1732 +/- 280. The pertussis component of the study vaccine would appear to be less reactogenic than United States whole cell pertussis vaccines but still immunogenic when given as a booster immunization to four to six year old children. Further studies are needed to assess reactions and immunogenicity in younger and previously unimmunized children.

Anorexia↗
PubMed1985

Cerebral localization of emotion based on clinical-neuropathological correlations: methodological issues.

The method of clinico-pathological correlation for drawing inferences about the localization of particular cerebral functions has a long history of use, and well established theoretical limitations. Release phenomena, loss of excitatory drive, as well as non-specific tissue responses to injury may all have a bearing on observed behavioral change. Nevertheless, the consistent observation that severity of depression in stroke patients is greater for left hemispheric strokes, and greater for left frontal versus left occipital strokes is of considerable interest. Site of lesion appears to have greater explanatory power for this emotional symptom than the obvious psychological explanations in terms of loss of self-esteem and loss of function. Depression is greater for strokes in general than would be expected for equivalent loss of motor function with orthopedic etiology. Loss of cognitive function likewise is a poorer guide to severity of depression than site of lesion. On the other hand, accuracy of lesion assessment using present static anatomical methods (CAT scan), and reliability and validity of the psychopathological examination present methodological difficulties which are discussed. As newer brain imaging techniques that are sensitive to function are developed, this line of enquiry holds considerable promise for furthering our understanding of the anatomy and physiology of emotion.

Brain Injuries↗
PubMed1985

Emotional correlates of structural brain injury with particular emphasis on post-stroke mood disorders.

This article reviews the emotional disorders which have historically been associated with brain injury and hypotheses about the nature of the relationship between emotional symptoms and neuropathology. Although a causal connection between emotional disorders and neurophysiological changes in the brain has been proposed, most clinicians have attributed the emotional disorders to a psychological response to the lesion-induced impairments. Relatively recent studies utilizing measurement of emotions, however, have suggested that emotional symptoms are not explained by severity of impairment. Studies of lateralization of emotional response to brain injury are discussed which exemplify the development of neurobiological theories for post-brain injury mood disorders. The importance of lesion size and location, time since injury, as well as physical and intellectual impairments and social factors on post-brain injury emotional disorders, are all reviewed in relation to recent findings. Results of a recent double-blind drug study suggest that post-stroke depressive disorders may be treatable with antidepressants.

Affect↗
PubMed1985

Social functioning assessment in stroke patients.

The influence of depression, intellectual function, and physical impairment on patient reports of social functioning was assessed by comparing responses obtained from 30 stroke patients with those obtained from an outside informant who knew the patient well. There was relatively good agreement between patient and other for both the overall score on the Social Functioning Examination (SFE) and individual items related to specific aspects of social functioning. Differences between scores obtained from a patient and outside informant were not significantly related to either depression, moderate degrees of intellectual impairment, relative closeness of patient and informant or to degree of physical impairment. These data suggest that valid SF assessments can be made either by a stroke patient who is capable of being interviewed or by a familiar outside informant. In addition, the prognostic utility of the SFE was examined by interviewing 50 patients during the acute stroke period and following them over six months. Social functioning in-hospital scores were not found significantly related to 6-month scores for either depression, intellectual impairment, or physical impairment, but depression and in-hospital impairment significantly predicted social functioning at 6-month follow-up. These data suggest that the most impaired stroke patients are the most likely to undergo social deterioration during the post-stroke period and may require the greatest amount of social intervention. Whether treatment of these variables significantly affects 6-month outcome remains an intriguing question for further study.

Activities of Daily Living↗
PubMed1984

Marked behavioral and biochemical sensitivity to lesion size in the posterior cortex of the rat.

Unilateral focal cortical suction lesions of varying diameter from 0.7 to 2.0 mm were made in the right posterior lateral cortex of rats. Only the 1.0 mm lesion size resulted in spontaneous postoperative hyperactivity. This increased activity was accompanied by significant elevations in substantia nigra and caudate nucleus dopamine concentrations. Other lesion sizes did not affect behavior or brain biochemical concentrations in this fashion. These results suggest a functional organization in this area of posterior cortex which affects both neurochemistry and behavior.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Fan-assisted hot-air ovens as sterilizers in doctors' surgeries.

A novel method of sterilization for use in doctors' rooms is described. Inexpensive domestic hot-air ovens that are easy to handle and require little maintenance attain temperatures more than adequate to kill bacteria, viruses and spores.

Evaluation Studies as Topic↗
PubMed1984

Asymmetrical cerebrovascular response to right and left hemisphere cortical suction lesions in the rat.

We have previously demonstrated that focal lesions of the right but not left cerebral cortex in the rat produce hyperactivity and depletions of norepinephrine. To assess the cerebrovascular response to suction lesions, postoperative rats were infused intravenously with [14C]inulin. The brain inulin concentration in the right lesion group was significantly higher than control (no surgery) or left lesion groups in all cortical quandrants, but most prominently in the quadrant posterior and contralateral to the lesion site.

Animals↗
PubMed1984

A laboratory assessment of the activities of four aminoglycosides.

An in vitro comparison of the activities of gentamicin, tobramycin, amikacin and netilmicin against selected clinical isolates showed differences in the susceptibility of individual strains to the four drugs, as well as substantial differences in sensitivity patterns between genera. Sensitive strains of Klebsiella and Enterobacter were most susceptible to netilmicin, but amikacin was more active against resistant strains. Tobramycin was most active against sensitive strains of Pseudomonas aeruginosa, but resistant strains were more susceptible to amikacin. In serious infections caused by these Gram-negative bacilli knowledge of the organism's identity and susceptibility may help in the selection of the most suitable aminoglycoside.

Amikacin↗