Biomedical subjects

S E Robinson

Publications and source records attributed to S E Robinson.

At least 37 records · Page 2Linked to original sources

PubMed2001

Effect of perinatal buprenorphine exposure on development in the rat.

The developmental effects of exposure to various doses of buprenorphine, methadone, or water during the perinatal period were studied in the rat. Rats were exposed to buprenorphine (0.3, 1.0, or 3.0 mg/kg/day), methadone (9 mg/kg/day), and/or water prenatally, postnatally, or both pre- and postnatally, via maternally implanted osmotic minipumps. Fetal and maternal mortality and morbidity were assessed, as well as the acquisition of several developmental milestones, pup weight gain, precipitated withdrawal, and the antinociceptive effect of morphine. Although perinatal exposure to buprenorphine failed to produce severe maternal and fetal or neonatal mortality, it was associated with a significant amount of perinatal mortality and perturbations of pup development. Pups developed physical dependence to both drugs, as evidenced by the ability of naloxone challenge to precipitate withdrawal. Both drugs induced tolerance to the antinociceptive effects of morphine in the tail-flick test. The effects of buprenorphine varied with the dose used, and the highest dose did not always produce the greatest effect. There were some similarities between the effects of perinatal buprenorphine and perinatal methadone; however, differences were also observed between the effects of the two drugs, which may be related to the different affinities and efficacies of the drugs at different opioid receptor subtypes.

Animals↗

PubMed2000

Theta rhythm increases in left superior temporal cortex during auditory hallucinations in schizophrenia: a case report.

Auditory hallucinations (AH), the perception of sounds and voices in the absence of external stimuli, remain a serious problem for a large subgroup of patients with schizophrenia. Functional imaging of brain activity associated with AH is difficult, since the target event is involuntary and its timing cannot be predicted. Prior efforts to image the patterns of cortical activity during AH have yielded conflicting results. In this study, MEG was used to directly image the brain electrophysiological events associated with AH in schizophrenia. We observed an increase in theta rhythm, as sporadic bursts, in the left superior temporal area during the AH states, whereas there was steady theta band activity in the resting state. The present finding suggests strong association of the left superior temporal cortex with the experience of AH in this patient. This is consistent with the hypothesis that AH arises from areas of auditory cortex subserving receptive language processing.

Adult↗

PubMed2000

Movement-related desynchronization of the cerebral cortex studied with spatially filtered magnetoencephalography.

Event-related desynchronization (ERD) within the alpha and beta bands on unilateral index finger extension and hand grasping was investigated on six normal volunteers with magnetoencephalography (MEG). A novel spatial filtering technique for imaging cortical source power, synthetic aperture magnetometry (SAM), was employed for the tomographic demonstration of ERD. SAM source image results were transformed into statistical parametric images. On the same hand grasping task, a functional MRI (fMRI) study was conducted on two subjects and compared with the ERD result. When the MEG data were analyzed with the fast Fourier transformation, power attenuation within the alpha and beta bands was evident on the contralateral sensorimotor area just prior to movement onset. The tomographic distribution of ERD was clearly obtained with SAM statistical imaging analysis. The equivalent current dipole (ECD) for the signal-averaged motor field was localized to the hemisphere contralateral to the hand movement, roughly at the center of the region displaying beta-band ERD. The signal increase on fMRI roughly colocalized with the ERD on the contralateral sensorimotor area. In conclusion, with the novel spatial filtering technique for the brain magnetic field, SAM, cortical regions contributing to ERD on finger movement were successfully demonstrated in a tomographic manner. The relative colocalization of the contralateral SAM ERD with ECD as well as the fMRI activation suggests that SAM is a practically useful technique to extract event-related signals from brain noise.

Adult↗

PubMed1999

Medial prefrontal cortex generates frontal midline theta rhythm.

Frontal midline theta rhythm (Fm theta) is a distinct theta activity of EEG in the frontal midline area that appears during concentrated performance of mental tasks in normal subjects and reflects focused attentional processing. To tomographically visualize the source current density distributions of Fm theta, we recorded Fm theta by using a 64-channel whole-head MEG system from four healthy subjects, and applied a new analysis method, synthetic aperture magnetometry (SAM), an adaptive beam forming method. Fm theta was observed in the MEG signals over the bilateral frontal regions. SAM analysis showed bilateral medial prefrontal cortices, including anterior cingulate cortex, as the source of Fm theta. This result suggests that focused attention is mainly related to medial prefrontal cortex.

Adult↗

PubMed1999

Our healthier hospital? The challenge for nursing.

AIM: This paper aims to explore the problems which are currently preventing hospital nurses from fulfilling their health promotion role, and makes recommendations for nursing managers. BACKGROUND: Hospital nurses have a key role to play in meeting recent Government proposals, which aim to enhance health promotion and public health in the NHS. KEY ISSUES: Lack of knowledge and skills, unhealthy hospital environments, poor collaboration, insufficient time and poor nursing management are impediments to hospital nurses promoting health. CONCLUSIONS: Hospital nurse managers need to capitalize on government enthusiasm by supporting health promotion education for nursing staff improving the hospital environment and facilitating better interdisciplinary working.

Health Knowledge, Attitudes, Practice↗

PubMed1998

Postnatal developmental regulation of neuronal nicotinic receptor subunit alpha 7 and multiple alpha 4 and beta 2 mRNA species in the rat.

This study examined the postnatal development of neuronal nicotinic receptor (nAChR) alpha 7, alpha 4 and beta 2 subunit mRNA in the Sprague Dawley rat brain. The hippocampus, septum and cortex were removed on postnatal day 1 (P1), P7, P14, or P28 and analyzed by sex. Northern analysis of cortical and pooled hippocampal and septal total RNA with 32P-alpha-dCTP-labeled alpha 7, alpha 4 (recognizing alpha 4.1 and alpha 4.2 mRNA), and beta 2 nAChR cDNA probes identified three (2.4, 3.8 and 8.0 kb) alpha 4, four (3.5, 5.0, 7.5 and 10.0 kb) beta 2 and a single 5.7 kb alpha 7 mRNA species. Cortical alpha 4 mRNA peaked on P14 and remained high on P28, whereas hippocampal/septal alpha 4 mRNA was higher on P7 and P14 than on P1 and P28. Expression of cortical and hippocampal/septal beta 2 mRNAs decreased on P7, followed by a dramatic peak on P14. alpha 7 mRNA peaked on P7. Throughout development, 2.4 kb alpha 4 mRNA was more intense than 3.8 kb alpha 4 mRNA, whereas 5.0 kb beta 2 mRNA was the most intense cortical and hippocampal/septal beta 2 mRNA species. The alpha 4.1-specific cDNA probe detected similar-sized alpha 4 bands as the pan-specific alpha 4 cDNA probe, therefore precluding the identification of any band as alpha 4.2-specific. These results suggest that postnatal expression of alpha 4 and alpha 7 but not beta 2 mRNAs is brain region-specific, and that the contribution of multiple nAChR subunit mRNA species in development may vary.

Aging↗

PubMed1998

Exposure to prenatal nicotine transiently increases neuronal nicotinic receptor subunit alpha7, alpha4 and beta2 messenger RNAs in the postnatal rat brain.

This study determined the effects of prenatal nicotine exposure (2 mg/kg/day) in Sprague Dawley CD rats via subcutaneously implanted osmotic minipumps, during gestational days 7-21, on postnatal levels of neuronal nicotinic receptor alpha4, alpha7 and beta2 subunit messenger RNAs. Northern analysis of postnatal day 1, 7, 14 and 28 hippocampal/septal and cortical total RNA using alpha-[32P]dCTP-labeled alpha4, alpha7 and beta2 complementary DNA probes identified a single (5.7-kb) alpha7 messenger RNA, three (2.4-, 3.8- and 8.0-kb) alpha4 messenger RNAs and four (3.7-, 5.0-, 7.5- and 10.0-kb) beta2 messenger RNAs. In comparison to prenatal saline, prenatal nicotine produced several significantly higher messenger RNA levels (cortical: 5.7-kb alpha7, 2.4-, 3.8- and 8.0-kb alpha4, 10.0-kb beta2; hippocampal/septal: 2.4- and 8.0-kb alpha4); these increases occurred predominantly on, but were not restricted to, postnatal day 14. Effects of nicotine were generally resolved by postnatal day 28. Collapsing the data across sex and age, a significant treatment effect indicated that hippocampal/septal and cortical 8.0-kb alpha4 messenger RNA levels and 10.0-kb beta2 messenger RNA levels were significantly higher following prenatal nicotine exposure. This is the first study indicating that prenatal nicotine produces alterations in developing postnatal rat neuronal nicotinic receptor messenger RNA levels, possibly by premature stimulation of neuronal nicotinic receptors. These results further implicate the teratogenic potential of nicotine in postnatal neuronal development.

Animals↗

PubMed1997

Extracellular aspartate concentration increases in nucleus accumbens after cocaine sensitization.

Rats were sensitized to cocaine (15 mg/kg, i.p.) by 6 daily injections followed by a 48 h withdrawal prior to cocaine challenge. Involvement of excitatory amino acids in behavioral sensitization was assessed by comparing extracellular levels of aspartate and glutamate in the core of the nucleus accumbens in response to the first cocaine injection and the final cocaine challenge. Intracerebral microdialysis of the nucleus accumbens in freely moving awake rats allowed the comparison of behavioral state with extracellular aspartate and glutamate concentrations. Increased nucleus accumbens extracellular concentration of aspartate, but not glutamate, was observed in rats exhibiting behavioral sensitization to cocaine.

Animals↗

PubMed1997

Recruitment and retention of psychosocial rehabilitation workers.

Recruitment and retention of direct service workers can be a major problem for administrators of community mental health organizations. This paper, based on a nationwide study of psychosocial rehabilitation workers and administrators, examines the congruity of worker and administrator perceptions of worker motivation for entering and leaving the field. Workers are motivated by the intrinsic nature of the work to enter into and stay in the field. Job burnout is as important as low pay in forcing workers out of the field. Administrators, however, perceive money to be a major factor motivating workers to enter the field and perceive external opportunities as forces that pull them away. Thus, administrators must address their workers' needs if their agencies are to offer quality services.

Adult↗

PubMed1997

Turnover intentions of community mental health workers in psychosocial rehabilitation services.

Staff turnover is an important topic for community mental health administrators. This paper reports on turnover intentions of PSR workers, a rapidly growing sector of the community mental health labor force as reported in a nationwide survey. A predictive model of intended turnover, suggested by literature in the field as well as study finding, included worker characteristics, job characteristics and worker attitudes. It was found that seven variables predicted intended turnover: younger age, higher emotional exhaustion, a feeling of lower job fulfillment, the lack of a perception of a career path, having a master's degree, having held a previous job in PSR and working with clients who have both a mental illness and AIDS. To assist agencies in reducing turnover, organizational policies and recommendations for staff development are discussed.

Adult↗

PubMed1996

Postnatal methadone exposure doe not prevent prenatal methadone-induced changes in striatal cholinergic neurons.

On postnatal day 4, rats exposed to methadone prenatally but fostered to control dams, as well as those fostered to dams treated with methadone, exhibited significant reductions in striatal acetylcholine (ACh) content. This suggests that neonatal withdrawal from methadone is not responsible for the effects of prenatal exposure on cholinergic development in the early perinatal period. The effects of perinatal exposure to methadone on serotonin (5HT) and dopamine (DA) metabolism do not appear to be strictly related to changes in ACh content. Although prenatal exposure reduces 5-hydroxyindole acetic acid (5HIAA) content, changes in 5HT content prevent significant changes in the ratio 5HIAA/5HT. Pups exposed to methadone only prenatally (withdrawal group) exhibited a decreased DOPAC/DA ratio, whereas pups in the treatment group exposed to methadone both pre- and postnatally exhibited an increased DOPAC/DA ratio.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1996

Perinatal exposure to methadone affects central cholinergic activity in the weanling rat.

Pregnant rats were implanted with osmotic minipumps containing either methadone hydrochloride (initial dose, 9 mg/kg/day) or sterile water. Their offspring were cross-fostered so that they were exposed to methadone prenatally and/or postnatally. Perinatal methadone exposure disrupted cholinergic activity on postnatal day 21 as measured by the turnover rate of acetylcholine (TRACh) in both female and male rats, although there were some sexually-dimorphic responses. The most profoundly affected brain region was the striatum, where prenatal exposure to methadone increased ACh turnover, whether or not the rats continued to be exposed to methadone postnatally. It appears unlikely that neonatal withdrawal contributes to brain regional changes in ACh turnover, as continued postnatal exposure to methadone did not prevent the prenatal methadone induced changes.

Acetylcholine↗

PubMed1996

Gestational cocaine and ethanol exposure alter spontaneous and cocaine-induced behavior in weanling rats.

The developmental and behavioral effects of prenatal exposure to cocaine and/or ethanol were examined in rats. Pregnant rats received ethanol (E; 2 g/kg, b.i.d.) orally, cocaine (C; 6 mg/kg/day, IV), or both (C/E) on gestational days 8-20. Controls consisted of pair-fed (PF) and untreated (UNT) groups. Offspring were weighed and examined for developmental markers beginning postnatal day one (PD1). On PD21 pups were individually observed in an open-field following either an injection of cocaine (10 mg/kg, IP), an injection of saline, or no treatment. Drug-treated and PF dams ate less food and gained less weight than the UNT dams. C and E litters had slightly increased mortality rates. Pups from both the C and E groups appeared less sensitive to the locomotor stimulant effect of cocaine. Pups from the E group engaged in significantly less spontaneous stereotypic locomotion than UNT and PF pups, while male pups from the C group exhibited a decrease in spontaneous exploratory behavior. Thus, prenatal exposure to C or E altered spontaneous and/or cocaine-induced behavior in weanling-aged rats, while the C/E combination did not augment either effect.

Animals↗

PubMed1996

Developmental consequences of intermittent and continuous prenatal exposure to 1,1,1-trichloroethane in mice.

The effects of 1,1,1-trichloroethane (TCE) on physical and behavioral development were examined in CD-1 mice prenatally exposed under two regimens. In the first study, pregnant mice were exposed to either 2,000 ppm TCE or filtered air for 17 hrs. during gestational days (GD) 12-17. A third group remained untreated. The results revealed no differences on pregnancy outcome. TCE-exposed pups gained less weight, exhibited delays in developmental landmarks and acquisition of the righting reflex, had poorer performance on tests of motor coordination and exhibited delays in negative geotaxis relative to sham or untreated pups. A second experiment was designed to more closely parallel the intermittent, acute, high-concentration pattern of solvent abuse. Pregnant mice were exposed for 60 min. to 8,000 ppm TCE or sham placement in exposure chambers three times/day during GD's 12-17. The results were very similar to what were obtained in the more continuous exposure study. TCE-exposed pups gained less weight, had delays in developmental landmarks and acquisition of the righting reflex and exhibited weaker grip strength, poorer negative geotaxis and less rooting intensity in comparison to sham pups. These data provide evidence for the behavioral and developmental teratogenicity of prenatal TCE exposure late in gestation.

Animals↗

PubMed1996

Perinatal methadone exposure produces physical dependence and altered behavioral development in the rat.

Pregnant rats were implanted with osmotic minipumps containing either methadone hydrochloride (9 mg/kg/day) or sterile water. Their offspring were cross-fostered so that the following prenatal/postnatal exposure groups were obtained: water/water, methadone/water, water/methadone and methadone/methadone. Methadone slightly reduced litter size, particularly the number of male offspring, and reduced litter birth weight. The induction or maintenance of physical dependence in the postnatal methadone exposure groups was confirmed by an experiment in which PD19 pups were challenged with naloxone (1 mg/kg, s.c.). Methadone concentrations were assayed in pup brain on postnatal days 4, 10 and 22. Postnatal exposure to methadone via maternal milk produced measurable levels of methadone which decreased with age. Neuromuscular and physical development were assessed. Exposure to methadone accelerated acquisition of the righting reflex, but tended to delay the acquisition of the negative geotaxic response. Postnatal exposure to methadone was associated with decreased somatic growth as measured through postnatal day 21. The older pups (postnatal day 21) exposed to methadone exhibited variations in activity levels: pups exposed to methadone both prenatally and postnatally exhibited the least amount of spontaneous locomotor activity and pups exposed only postnatally exhibited the most activity. Therefore, it is possible to induce and/or maintain physical dependence via lactation in rat pups fostered to methadone-treated dams. Perinatal exposure to methadone by this route produces several subtle disruptions of pup development in the absence of gross maternal or fetal toxicity.

Analysis of Variance↗

PubMed1996

The pharmacology of respiratory disorders related to anesthesia.

The pharmacology of disorders of the respiratory system focuses on one major parameter--bronchodilatation. Drugs are rated as effective purely on how well they reverse brochoconstriction. Patients' conditions are considered reversible if there is a 20% increase in flow rates after a bronchodilator is administered. This article evaluates many of the drugs used in the treatment of reactive airway diseases such as asthma. Particular emphasis is placed on the anesthetic drugs used during the perioperative period.

Anesthetics↗

PubMed1995

Cocaine increases extraneuronal levels of aspartate and glutamate in the nucleus accumbens.

Intracerebral microdialysis was used to assess the effects of cocaine-HCl on extracellular concentrations of the excitatory amino acids aspartate and glutamate in the nucleus accumbens of awake, freely moving rats. After an initial equilibration period, cocaine (7.5, 15 or 30 mg/kg) or saline was injected i.p., and samples were collected for an additional 2 h. The highest dose of cocaine (30 mg/kg, i.p.) caused a 4-fold increase in glutamate levels and an 18-fold increase in aspartate levels over baseline. To verify that the source of the extracellular aspartate and glutamate was neuronal, additional experiments were conducted using Ca(2+)-free microdialysis buffer, and buffer containing 10 microM tetrodotoxin. Local perfusion with Ca(2+)-free buffer reduced the increase of extracellular aspartate and glutamate in rats injected with 30 mg/kg cocaine. Tetrodotoxin significantly decreased the cocaine-induced increase in excitatory amino acids, but not the behavioral response.

Analysis of Variance↗

PubMed1995

Effects of cocaine and the cocaine analog CFT on glutamatergic neurons.

The effects of cocaine and the cocaine analog methyl-3-beta-(p-fluorophenyl)-1 alpha H, 5 alpha H-tropane-2b-carboxylate (CFT) on glutamate turnover rate were studied in the nucleus accumbens, striatum, frontal cortex, and parietal-cingulate cortex of the rat, using neurotransmitter turnover rate as an estimate of the activity of the glutamatergic neurons. Both cocaine [15 or 30 mg/kg, intraperitoneally (IP)] and CFT (2.2 mg/kg, IP) increased glutamate turnover in the nucleus accumbens, although the time course of their actions differed. These effects on glutamate turnover appeared at times after maximal motor activation of the animals had occurred. On the other hand, neither cocaine nor CFT affected glutamate turnover in the frontal cortex, parietal-cingulate cortex, or striatum. Neither cocaine nor CFT affected the content of glutamate or glucose in any brain region studied. Thus, although cocaine and CFT affect glutamatergic neurons in the CNS, these actions are not generalized across the CNS, but are restricted to a specific brain region.

Analysis of Variance↗