PubMed Health⌕ Search

Biomedical subjects

J Pine

Publications and source records attributed to J Pine.

7 recordsLinked to original sources
PubMed1991

An apparatus for recording synaptic potentials from neuronal cultures using voltage-sensitive fluorescent dyes.

Voltage-sensitive dyes offer the promise of noninvasive multicell recording of electrical activity, and should therefore be useful for studying the synaptic interactions of small networks of cultured neurons. We have designed and built a system for recording from microcultures of 1-15 neurons from the rat superior cervical ganglion (SCG), using voltage-sensitive fluorescent dyes of the styryl class. The apparatus comprises a standard inverted epifluorescence microscope; a mercury arc lamp with an optical feedback regulator; a 256-pixel fiber-optic camera with individual photodiode detectors and very low-noise amplifiers; and a personal computer-based data acquisition system. Its dark noise and illumination fluctuations are low enough that at typical fluorescence levels for these cells, it is limited by shot noise (the inherent physical limit of detection). Recording from SCG neurons, the signal-to-noise ratio is high enough to see large subthreshold synaptic potentials without signal averaging. This apparatus should be useful for studying long-term synaptic plasticity in cultures of vertebrate neurons, and several of its features should apply to optical recording from other preparations.

Analog-Digital Conversion↗
PubMed1991

Voltage-sensitive dye recording of action potentials and synaptic potentials from sympathetic microcultures.

Given the appropriate multicell electrophysiological techniques, small networks of cultured neurons (microcultures) are well suited to long-term studies of synaptic plasticity. To this end, we have developed an apparatus for optical recording from cultured vertebrate neurons using voltage-sensitive fluorescent dyes (Chien, C.-B., and J. Pine. 1991. J. Neurosci. Methods. 38:93-105). We evaluate here the usefulness of this technique for recording action potentials and synaptic potentials in microcultures of neurons from the rat superior cervical ganglion (SCG). After extensive dye screening and optimization of conditions, we chose the styryl dye RH423, which gave fast linear fluorescence changes of approximately 1%/100 mV for typical recordings. The root mean square noise of the apparatus (limited by shot noise) was typically 0.03%, equivalent to 3 mV of membrane potential. Illumination for at least 100 flashes of 100 ms each caused no noticeable photodynamic damage. Our results show that voltage-sensitive dyes can be used to record from microcultures of vertebrate neurons with high sensitivity. Dye signals were detected from both cell bodies and neurites. Signals from presumptive dendrites showed hyperpolarizations and action potentials simultaneous with those in the cell body, while those from presumptive axons showed delayed propagating action potentials. Subthreshold synaptic potentials in the cell body were occasionally detectable optically; however, they were usually masked by signals from axons passing through the same pixel. This is due to the complex anatomy of SCG microcultures, which have many crisscrossing neurites that often pass over cell bodies. Given a simpler microculture system with fewer neurites, it should be possible to use dye recording to routinely measure subthreshold synaptic strengths.

Action Potentials↗
PubMed1989

Sealing cultured invertebrate neurons to embedded dish electrodes facilitates long-term stimulation and recording.

Recently it has become possible to form small networks of synaptically connected identified invertebrate neurons in culture. Using conventional saline-filled glass electrodes, it is difficult to simultaneously stimulate and record from more than 2 or 3 cultured neurons and to perform experiments lasting longer than several hours. We demonstrate that it is possible to overcome these limitations by using planar arrays of electrodes embedded in the bottom of a culture dish. The arrays employ conductive leads and insulation that are transparent, making the dishes compatible with voltage-sensitive dyes and inverted microscopy. Identified neurons from leech Hirudo medicinalis, slug Aplysia californica, and snail Helisoma trivolvis, have been grown on these arrays. Due to their large size (soma diameter 40-200 microns) these neurons form seals over the dish electrodes. Individual electrodes can then be used to stimulate and to record action potentials in the associated neuron. With sealing, action potentials have been recorded simultaneously from many neurons for up to two weeks, with signal-to-noise ratios as large as 500:1. We developed and tested a simple model that describes the voltage waveforms measured with array electrodes. Potentials measured from electrodes under cell bodies were primarily derivatives of the intracellular potential, while those measured from electrodes under axon stumps were primarily proportional to local inward Na+ currents. While it is relatively easy to record action potentials, it is difficult to record postsynaptic potentials because of their small size and slow rate of rise.

Action Potentials↗
PubMed1987

Quantitative imaging and microanalysis with a scanning soft x-ray microscope.

A scanning soft x-ray microscope has been developed that uses synchrotron radiation focused by a Fresnel zone plate to form a submicron beamspot on the specimen. Transmitted x-rays are detected and used to form a quantitative map of specimen absorptivity. Applications of the instrument to the imaging of whole wet cells and to the mapping of calcium in sections of bone are presented, with a resolution of 300 nm and an elemental sensitivity of 2 micrograms cm-2.

Animals↗
PubMed1986

Seat belt education program--a model for public health settings.

A cohort of 268 low-income mothers participating in the Women, Infants, and Children (WIC) Supplemental Food Program was enrolled in a seat belt education and motivation program. The goal of the study was to determine whether seat belt use could be increased by incorporating a brief educational intervention into an existing public health program. Seat belt use was monitored by an unobtrusive observer prior to and one month following the intervention. Seat belt use increased from a baseline of 4.9 to 12.6% one month following education (p less than .01).

Adult↗
PubMed1986

Child restraint law effects on motor vehicle accident fatalities and injuries: the New Mexico experience.

The New Mexico State Legislature passed a child restraint law applicable to children less than 5 years of age that became effective in June 1983. To evaluate the effectiveness of this law, we analyzed traffic accident data for New Mexico from January 1981 through September 1984. During this period, there were 20,972 children younger than 5 years of age in motor vehicle accidents. Restraint usage increased for this age group from a low of about 10% in 1981 to more than 40% in 1984 (P less than 10(-6)). Unrestrained children younger than 5 years of age were five times more likely to be killed and two times more likely to be injured than restrained children. Analysis of motor vehicle accident fatality and injury rates pre- and post-law revealed a 33% reduction in motor vehicle accident fatality rates and a 12.6% reduction in nonfatal injury rates for children younger than 5 years. We conclude that child restraint devices are effective in reducing motor vehicle accident fatalities and injuries in young children and the child restraint law has been effective in increasing child restraint usage and in reducing childhood death and injury in New Mexico.

Accidents, Traffic↗