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Biomedical subjects

W W Francis

Publications and source records attributed to W W Francis.

15 recordsLinked to original sources
PubMed1990

An infrared heat source for temperature control of a small microscope flow bath.

A simple, inexpensive, and easily installed infrared heat source with temperature controller for small superfusion baths used in electrophysiologic experiments is described. The output of a thermal sensor in the bath is amplified and sent to a feedback circuit which in turn controls the voltage supplied to a tungsten/halogen bulb focused on the bath. Fluctuation from the set point is no more than 0.2 degrees C with good fluid level control. Judging from the lack of change in the cardiac action potential duration, heart cells do not preferentially absorb infrared radiation.

Action Potentials↗
PubMed1987

Arterial rupture without balloon rupture during percutaneous transluminal angioplasty.

A 58-year-old man with severe left lower extremity claudication and rest pain underwent percutaneous transluminal angioplasty. A high-pressure balloon was inflated in an area of severe atherosclerotic narrowing. The patient complained of severe pain during inflation and had a vasovagal response. After balloon deflation, angiography displayed extravasation just inferior to the lower edge of the balloon. Immediate inflation of the balloon tamponaded the leak and allowed the patient's transfer to the operating room in stable condition. It is hypothesized that the new high-pressure balloons can overcome resistance in nondistensible arterial walls, causing rupture without balloon rupture.

Angioplasty, Balloon↗
PubMed1978

Acute fulminating transmural ileocolitis after small bowel bypass for morbid obesity.

A personal series of small bowel bypass operations for morbid obesity is presented. The importance of careful considerate follow-up by the operating surgeon is stressed. The development of acute fulminating transmural ileocolitis, Crohn's disease, in a patient twenty-two months after such surgery is reported and considered merely a dangerous coincidence, combining an acute colonic disease with a short small intestine.

Adult↗
PubMed1975

A method of quantitating injury inflicted in acute spinal cord studies.

Spinal cord trauma was induced in cats and Rhesus monkeys using an improved method which allows for accurate quantitation of the force delivered. The materials and methods described consist of a weight which is dropped down a centre shaft on to a strain gauge arch assembly which transfers the force to a teflon impounder resting on the exposed dura of the cord. The force transferred from the weight to the impounder is recorded by the strain gauge and thr force curve can be displayed on a storage oscilloscope. The force delivered to the cord can thus be photographed and quantitated. The construction of the strain gauge assembly and the application of the apparatus are discussed.

Animals↗
PubMed1975

A self-contained calibration unit for use with intracellular recording systems.

A relatively inexpensive solid state device designed for calibration of amplifiers and recorders used in microelectrode studies is described. The device is imposed between the ground electrode and the amplifier and provides three calibration signals; 100 mV DC for calibrating amplitude a variable-frequency square wave, 100 mV in amplitude use for capacitance neutralization, and a 100-mV, essentially square-wave signal with variable rate of rise and fall used for calibrating electronic differentiating circuits. The instrument is self-contained and battery powered. It was designed to remain in the circuit while recording. Calibration can be accomplished with the microelectrode in the circuit or with a dummy load.

Amplifiers, Electronic↗