An inexpensive restraint for small animals

An animal restraint is described that can be built in the laboratory from a piece of Plexiglas and a few inches of Velcro.     

An inexpensive sensor for measuring surface geometry

A technique to measure surface geometry using a conductive ink sensor is described. In the human system distorted cylinders are common, and geometry can be reconstructed from local measures of curvature. An algorithm is presented to reconstruct the shape of a surface from a series of curvature measurements. The Abrams Gentile Entertainment patented bend sensor was evaluated as a curvature transducer. The sensor was tested at the extremes of the likely measurement range, from curvatures below 0.01 mm⁻¹ up to a curvature of 0.1 mm⁻¹. The upper curvature limit proved beyond the design specification of the sensor. The technique was applied at the lower curvature range to reconstruct one quadrant of the chest of a volunteer and record breathing movement. The bend sensor is inexpensive and can be applied to obtain an approximate reconstruction of surface geometry in the human system.     

An inexpensive circuit for recording mean heart-rate

A circuit and technique are described for recording mean heart-rate from rats. This method obviates the use of a polygraph for recording the EKG and eliminates errors inherent in computing heart-rate from polygraph records.     

An inexpensive surgical headholder for the rat

In many surgical procedures, there is a need to secure the animal's skull in a particular orientation. Described here is a surgical headholder for the rat that is inexpensive and easily constructed. The main component of the headholder is a screw type tubing clamp that is modified to allow the hard palate of the rat to be rigidly secured to the base plate of the clamp. This headholder has proven to be a highly satisfactory alternative to commercially available devices.     

An inexpensive dual-excitation apparatus for fluorescence microscopy

Ion sensitive indicator molecules can be employed in conjunction with fluorescence microscopy in single cells to measure rapid changes in the intracellular concentration of several ionic species. A number of these probes (e.g. fura-2) require the capability of measuring emission intensity at two excitation wavelengths to quantitate properly intracellular ion concentration. We have developed a simple dualexcitation apparatus for use in such applications. The apparatus switches the excitation filter within 150 ms. This economical apparatus is well suited in situations where the ionic concentration of interest is changing relatively slowly. Moreover, by synchronizing the device's action with an external stimulus; rapid and reproducible ionic changes in excitable tissue also can be measured.Supported by grants AM-01186, DK-32333, HL-20859 and HL-28958 from the USPHS; Dr. Robinson is an Established Fellow of the New York Heart Association; Dr. Steinberg held a Squibb Cardiovascular Research Fellowship Award during the time this research was accomplished     

An inexpensive kVp penetrameter

In this report we describe an improvement upon the design by Stanton and Lightfoot for a simple photographic null method to determine the kVp of a diagnostic region x-ray source. The new version has two primary advantages over the Ardran and Crooks design in that it is both simpler and less expensive to produce.     

An inexpensive rotating connector for chronic intragastric infusion

It has been a common practice to express food and water intake as a proportion of body weight in an attempt to control for weight differences between individuals or treatment groups. It is argued here that, unless extreme caution is taken, this procedure is likely to result in misleading conclusions. Intake per kilogram body weight is not simply a measure of intake and it should not be treated as though it were. Furthermore, use of this technique to measure ingestion is more likely to introduce spurious relations between consumption and body weight than it is to eliminate relations which are actually present. We feel, therefore, that this measure should, at most, be used as a supplement to raw measures of food and water intake.     

An inexpensive sleep-wake state analyzer for the rat

Manual classification of sleep stages is a tedious and time consuming task. We describe an inexpensive system for sleep-wake state classification for as many as eight rats at a time. It is based on determining threshold values for each parameter of each rat, then finding the natural transitions from one sleep state to another and finally classifying these states utilizing the cortical EEG and EMG signals.     

An inexpensive patient-encounter log.

Many medical schools use patient-encounter log forms to document and improve training experiences; however, they are expensive and/or time-consuming to analyze. The patient-encounter log form developed at the University of Hawaii is a one-page form on which students in the family medicine clerkship are required to maintain a daily record of patient demographics and diagnoses. The form is reviewed throughout the clerkship, and efforts are made to ensure that students' learning is supplemented to cover any gaps discovered with the log forms. The simple paper log form can be visually analyzed in less than a minute. During the initial implementation period, 44 students completed the forms. Twelve of these students also returned an end-of-year survey, which indicated that updating the logs required less than one minute per patient. The information obtained from the log forms was used to document and improve the consistency of the educational experience and to establish clinical curriculum guidelines for the clerkship. This form can easily be reproduced and adapted to other settings.