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Biomedical subjects

J Patrick

Publications and source records attributed to J Patrick.

267 records · Page 15Linked to original sources
PubMed1972

Appearance of acetylcholine receptors during differentiation of a myogenic cell line.

Acquisition of acetylcholine receptors during differentiation of a clonal myoblast cell line was monitored with a neurotoxin isolated from venom of the Indian Cobra Naja naja. Toxin bound specifically and reversibly to acetylcholine receptors of the differentiated cells. Specificity of the binding reaction was assayed by measurement of the ability of various cholinergic agonists and antagonists to compete with neurotoxin for its binding site. The rate of toxin binding paralleled the rate of inactivation of functional acetylcholine receptors, as measured by iontophoretic application of acetylcholine. Bound toxin was released from the cells with a half-life of about 7 hr. This release was not associated with a decrease in the total number of toxin-binding sites. A slow hyperpolarizing response to acetylcholine seen in myoblasts was insensitive to toxin; the appearance of toxin-binding sites parallels the appearance of fused fibers during differentiation of the muscle cells in tissue culture.

Acetylcholine↗
PubMedDate not supplied

Isolation of a cDNA clone coding for a possible neural nicotinic acetylcholine receptor alpha-subunit.

We have isolated a complementary DNA clone containing sequences homologous to those encoding the alpha-subunit of a mouse muscle nicotinic acetylcholine receptor. Based on the structural similarities between the encoded protein and the muscle acetylcholine receptor alpha-subunit, and the presence of hybridizing RNA species in the brain, we propose that this clone codes for a neural nicotinic acetylcholine receptor alpha-subunit.

Amino Acid Sequence↗
PubMedDate not supplied

Human processes of control: tracing the goals and strategies of control room teams.

This study utilized a process tracing methodology to analyse the goals and strategies of control room teams in dealing with an unpredicted plant disturbance. The human processes of control used by operators and their supervisors, and interactions between them, were analysed during phases of detection, diagnosis, and control of a small plant leak. Five control room teams were videotaped tackling this simulated scenario on a full-scale simulator. The results found substantial differences both within and between teams in how the goals of monitoring and implementing procedures during the detection phase, and problem-solving and plant control during the diagnosis phase were achieved. The temporal patterning of the activities associated with these goals revealed that the teams used different strategies. The training implications of these findings are discussed, in particular with respect to the control room supervisor who had a pivotal role.

Cognition↗
PubMedDate not supplied

Alpha7 nicotinic receptor subunits are not necessary for hippocampal-dependent learning or sensorimotor gating: a behavioral characterization of Acra7-deficient mice.

The alpha7 nicotinic acetylcholine receptor (nAChR) subunit is abundantly expressed in the hippocampus and contributes to hippocampal cholinergic synaptic transmission suggesting that it may contribute to learning and memory. There is also evidence for an association between levels of alpha7 nAChR and in sensorimotor gating impairments. To examine the role of alpha7 nAChRs in learning and memory and sensorimotor gating, Acra7 homozygous mutant mice and their wild-type littermates were tested in a Pavlovian conditioned fear test, for spatial learning in the Morris water task, and in the prepulse inhibition paradigm. Exploratory activity, motor coordination, and startle habituation were also evaluated. Acra7 mutant mice displayed the same levels of contextual and auditory-cue condition fear as wild-type mice. Similarly, there were no differences in spatial learning performance between mutant and wild-type mice. Finally, Acra7 mutant and wild-type mice displayed similar levels of prepulse inhibition. Other behavioral responses in Acra7 mutant mice were also normal, except for an anxiety-related behavior in the open-field test. The results of this study show that the absence of alpha7 nAChRs has little impact on normal, base-line behavioral responses. Future studies will examine the contribution of alpha7 nAChR to the enhancement of learning and sensorimotor gating following nicotine treatments.

Animals↗
PubMedDate not supplied

Disposition of ethanol and its proximate metabolite, acetaldehyde, in the near-term pregnant ewe for short term maternal administration of moderate-dose ethanol.

The effect of short term maternal ethanol administration on the disposition of ethanol in the ovine maternal-fetal unit was determined. Eleven conscious instrumented near-term pregnant ewes (between 125 and 134 days of gestation; term, 147 days) received 1-hr iv infusion of 1 g of ethanol.kg of maternal body weight-1.day-1 for six days (N = 6 ewes) or an equivalent volume of saline for six days (N = 5 ewes). On the seventh day, the ethanol- and saline-pretreated animals were administered 1 g of ethanol.kg of maternal body weight-1. Ethanol and acetaldehyde concentrations were determined by headspace GLC in maternal blood, fetal blood, and amniotic fluid samples obtained at selected times during the 14-hr study. The data demonstrated that short term maternal administration of once-daily moderate dose ethanol did not produce major changes in the disposition of ethanol and its proximate metabolite, acetaldehyde, in the maternal, fetal, and amniotic fluid compartments during near-term ovine pregnancy.

Acetaldehyde↗
PubMedDate not supplied

An overview of the regulatory aspects of medical devices from the viewpoint of research and device manufacturing.

PURPOSE: To review the Food and Drug Administration's regulatory requirements for bringing a new or substantially changed medical device to market in the United States, noting the history and current requirements for the continuous spinal catheter. METHOD: The relevant laws and guidelines for classifying, testing, and submitting a device to Food and Drug Administration approval are reviewed. RESULTS: The Food and Drug Administration categorizes medical devices into three classes, based on potential risk for illness or injury presented by a malfunction or failure. Class III devices are the most critical ones, and require a Premarket Approval that includes clinical trials before market introduction. Classes I and II usually require a 510(k), or premarket notification, which usually does not need any clinical data. Testing requirements include biocompatibility testing; physical, functional, and packaging testing; and sterility testing. The continuous spinal catheter (25-32 gauge) was marketed under a 510(k) claiming substantial equivalence to the Bizzarri-Giuffrida 24-gauge catheter, which was a pre-Amendment device. After incidences of cauda equina syndrome were reported with use of the continuous spinal technique, the Food and Drug Administration reclassified the small-gauge catheters as Class III devices, which require a Premarket Approval before being marketed.

Equipment and Supplies↗