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Biomedical subjects

J R Searle

Publications and source records attributed to J R Searle.

8 recordsLinked to original sources
PubMed1991

Development of an ambulatory recorder for evaluation of muscle tension-related low back pain and fatigue in soldiers' normal environments.

We have developed an ambulatory recorder capable of monitoring low back muscle tension, trunk motion, and ratings of pain and fatigue. It weighs 22 ounces, fits into a canteen belt, and records every second for 18 hours. Eleven subjects wore the recorder during all walking hours for between 3 and 5 days. Six subjects had chronic low back pain due to muscle tension, three experienced low back pain after labor, and two had no pain. Movement and muscle tension correlated highly when subjects were pain free but not when they were in pain. Muscle tension increased before pain was experienced.

Back Pain↗
PubMed1989

A rapid heating and cooling rate dilatometer for measuring thermal expansion in dental porcelain.

Herein we describe a dilatometer that consists of a low-mass infrared furnace for rapid heating or cooling, an optical pyrometer, and a laser interferometer. The dilatometer facilitates observations of thermal expansion at rates comparable with those in dental laboratory practice over the temperature range necessary for comparison of thermal expansion of dental porcelain and alloy. Examples of thermal expansion data obtained at a 600 degrees C/min heating rate on NIST SRM 710 glass and dental porcelain are reported. To a limited extent, thermal expansion data above the glass-transition temperature range of dental porcelain were obtained. A shift of the glass-transition temperature range to higher temperatures was observed for both materials, compared with data obtained at 20 degrees C/min.

Chemical Phenomena↗
PubMed1989

Gingival resistance to probing forces. I. Determination of optimal probe diameter.

This paper presents the results of a study designed to determine (1) if advancement of a periodontal probe under a given force against healthy gingiva differed from its advancement under a similar force, against inflamed gingiva, and (2) to select the diameter which best distinguishes healthy gingiva from that which is inflamed to varying degrees. The teeth of eight beagle dogs were cleaned three times per week for two months until a Gingival Index (GI) of 0 and gingival fluid flow (GFF) of 9 or less, as measured by the Periotron, were obtained. Probes of diameters 0.4, 0.6, 0.7, and 0.8 mm were advanced perpendicularly against the attached gingiva in the incisor, premolar, and molar regions by an electromechanical device which simultaneously plotted force versus displacement following initial contact of the probe tip with the gingiva. These forces ranged from 0.1 to 0.9N. This process was repeated in the same animals following cessation of plaque control measures when the GI reached a value of 1 and GFF reached levels of 10 to 19. It was repeated again following placement of an irritating ligature when GI reached 2 and GFF greater than 20. An analysis of covariance showed significant differences between all three levels of health and disease for all probe diameters. F values for the 0.6 mm probe were highest at all probing forces indicating that this diameter most consistently discriminated variation of gingival health status.

Animals↗
PubMed1989

Gingival resistance to probing forces. II. The effect of inflammation and pressure on probe displacement in beagle dog gingivitis.

This study was undertaken to determine the effect of gingival inflammation and probing pressure on probe tip placement in relation to the base of the gingival crevice and the most coronal connective tissue attachment fibers. Nine young male beagle dogs were divided into three groups as determined by clinical status of the gingiva following implementation of a protocol designed to produce gingival health and disease. An electromechanical device was used to advance 0.6 mm diameter probes into the facial gingival crevices of selected teeth and to obtain force-displacement curves. The instrument stopped the probe at pressure of either 80, 160, 320, 640, 1280, or 2560 kPa which were randomly allocated to 12 test teeth in each dog. After the probe came to rest, it was attached to the tooth. When all 12 probes were attached, the animal was sacrificed. Blocks consisting of gingiva, probe, and tooth were processed to obtain two buccolingual sections, one containing the probe and the other immediately adjacent to it. Clinical and histometric measurements were performed and the data evaluated. Although three groups of animals were discernable by clinical criteria, only two groups, health and disease, could be formulated based on the degree of histologic inflammation. The histologic grouping was used in data analysis. Histometric distances from the cemento-enamel junction to the base of the crevice (cJ), to most coronal connective tissue attachment (cC) and to the probe tip (cP) all increased with change from health to disease. However, changes in health/disease did not influence difference between distances (cP-cJ,cP-cC).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Computerized analysis of resting fetal heart rate tracings.

Previous attempts to computerize the analysis of fetal heart rate (FHR) using mainframe or minicomputers were not accepted in routine clinical practice because of their complexity, cost, and lack of validation. We describe the first practical, inexpensive system integrated into a clinical protocol that analyzes and documents FHR baseline, long-term variability, and episodic events using a standard microcomputer. A comparison of computerized and manual analyses of 284 nonstress tests (NSTs) of high-risk patients revealed no significant differences in determining the number of acceleration and deceleration events and mean FHR baseline. Long-term variability and other reported data could not be compared for lack of manual techniques. The combination of standardized analysis and quantified data may improve the predictive value of the computerized NST compared with the visually analyzed NST. Other benefits include computerized archiving, data transmission by telephone, and linkage to a perinatal data base.

Diagnosis, Computer-Assisted↗