John R. Searle

Maternal dietary substrates and human fetal biophysical activity. I. The effects of tryptophan and glucose on fetal breathing movements

To study the effects of L-tryptophan and glucose on fetal breathing activity, we examined 40 women with normal term pregnancies, randomly assigned to four equal groups who either continued fasting (group C), received 1 gm of oral tryptophan (group T), received 100 gm of oral glucose (group G), or received both substrates (group T + G). Studies lasted 210 minutes, during which fetal breathing movements were observed with real-time ultrasonography and entered and analyzed for incidence, rate, and variability on a microcomputer. Plasma glucose and tryptophan levels were determined every 30 minutes. The incidence of fetal breathing movements declined in group C and rose significantly in the other groups. Breathing rates were unchanged in groups C and T but rose significantly in groups G and T + G during peak breathing intervals. Breath interval variability did not change significantly in any study group. Maternal administration of tryptophan is associated with an alteration in fetal breathing activity but to a lesser degree than that observed after maternal glucose loading.

Computer-assisted assessment of the fetal biophysical profile

The biophysical profile assesses fetal heart rate, breathing movements, fetal body movements, amniotic fluid volume, and fetal tone. In the past, these data have been scored by an arbitrary, unweighted system. While this approach is useful in detecting major anomalies and oligohydramnios, both static observations, the dynamic variables (fetal heart rate, fetal breathing movements, and fetal body movements) have added little information beyond that of an extended nonstress test alone. We have evaluated an alternative biophysical assessment system, modeled after extended physiologic studies, which not only acquires dynamic fetal variables simultaneously but, with computer assistance, quantifies the biophysical information. With an ADR 4000/L scanner, a Hewlett-Packard 8040 A monitor, and a specially programmed IBM microcomputer, we studied 100 normal term fetuses during 60-minute epochs. Each gestation had normal amniotic fluid volume and fetal tone. Normative values for the dynamic variables, expressed as means +/- SD were: fetal heart rate, 137 +/- 6.3 bpm; incidence of fetal breathing movements, 25.0% +/- 17.3%; rate of fetal breathing movements, 46.0 +/- 9.4 breaths/min; total fetal breathing movements, 823 +/- 61; incidence of fetal body movements, 8.5% +/- 3.9%; accelerations (greater than 15 bpm, 15 seconds), 14.1 +/- 6.3. We conclude that this approach is practicable, respects the biologic cycles of fetal behavior, and provides a basis for population standards and sequential study of the same fetus.

Electrophysiological changes in the primary sensory neuron following subchronic soman and sarin: Alterations in sensory receptor function

Cats were administered soman or sarin either in a single high dose (1 mg/kg) with pretreatment or in multiple sublethal doses to determine whether these potent organophosphorus agents could produce a delayed neurotoxicity and what, if any, pathophysiological changes occurred in peripheral sensory receptors. Neither soman nor sarin, when administered as a single high dose, produced a delayed neurotoxicity as observed behaviorally for up to 60 days. There were also no observable signs of delayed neurotoxicity when these agents were administered in multiple doses. Functional tests of proprioceptors and mechanoreceptors were performed on the cats which received multiple sublethal doses of either soman or sarin. It was found that the discharge rates of muscle spindle primary endings were depressed while the discharge rates of secondary endings were facilitated following the administration of either soman or sarin. The discharge rates of slowly adapting type 1 mechanoreceptors were also depressed. The total number of identified mechanoreceptors was reduced in both the soman- and sarin-treated animals. Conduction velocities of several of the muscle spindle and mechanoreceptor afferents were significantly decreased. The alterations in muscle spindle function may be due to changes in the muscle resulting from acetylcholinesterase inhibition. Another explanation for the changes in both muscle spindle and mechanoreceptor function may be the direct effect of the organophosphorus agents on the afferents themselves, thus altering their excitability.

An Approach to Intensive Care Monitoring That Combines Deterministic And Heuristic Techniques

Patient monitoring in Intensive Care Units (ICUs) requires the acquisition of a large amount of information and/or data. This information will be later analyzed and interpreted by clinical specialists. The task becomes particularly crucial when it involves intensive care units that incorporate a large number of beds. Most engineering efforts in the field have followed two different approaches: 1) Construction of systems and mechanisms for massive data acquisition, storage and processing of data, and appropriate display of the results; and 2) Building expert systems. This paper presents the basis for an alternative approach which combines deterministic and heuristic techniques. The approach also takes into account the possibility of reasoning under uncertainty; one of the intrinsic characteristics of the clinical inferential processes.

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.

NST expert: an intelligent program for NST interpretation

An intelligent program for the analysis and interpretation of the nonstress test (NST) is described. The NST takes baseline fetal heart rate (FHR) data from electronic FHR monitors and relates the data to fetal activity. It is stressed the test should not only consider the raw FHR data, referenced to a scale of normal or critical parameter values, but should also account for the pregnancy risk factors for which the test was indicated. The incorporation of explanatory modules that run in parallel and justification structures extends the applicability of the program and provides a tool for the training of future experts.<<ETX>>

A portable activity monitor for musculoskeletal pain disorders

A portable activity monitor (PAM) designed for simultaneously recording and quantifying surface electromyograph (EMG) signals and body movements in the natural environment is discussed. The data are transferred to a personal computer for graphic display, statistical analysis, and storage. A table of PAM system specifications is given. The system is currently being used to determine the relationships between onset and intensity of low back pain, patterns of paraspinal muscle contraction, and the intensity and duration of normal everyday activities.<<ETX>>

Obstetrical Decision-riaking Based On Predictive Expert Analysis

This article describes the validation results of the prognostic module for the obstetrical expert system NST-EXPERT. The validation method consists of calculating the percentages of man/machtne agreement for the expert system and a team of three perinatologists. This comparison was carried out for the following three categories: man neonatal outcome prediction vs. machine neonatal outcome prediction, madmachine outcome prediction vs. real outcome and man/machine bad outcome prediction vs. real bad outcome. The results obtained suggest that the use of prognostic

Implementing Uncertainty-based Prognostic Structures In NST-EXPERT

The Peld of obstetrics is virtually unexplored from the expert systems point of view. Among the first efforts in this _field were those undertaken in developing the expert system FOETOS [I], f21, which performed a diagnosis, prognosis and therapy of fetal status in various antepartum tests [Non Stress Test [NSTl, Fetal Biophysical Profile [BPPI and Contraction Stress Test [CSTIJ, intrapartum course and early neonatal Iije This paper describes the prognostic features of NST-EXPEEYT [3], an obstetric expert system designed to assist the clinician in evaluating and interpreting the non-stress test. and to render a prognosis of fetal outcome.

A Sensor To Measure Spinal Mobilization Forces

We have tested a modified version of the Interlink force sensor to asses its potential as a tool to measure spinal mobilization forces. The sensor was sandwiched between two metal disks to eliminate the effect of shearing forces. The sensor output voltage is a reproducible, linear function of force applied to the sensor, but it depends on the area over which the force is applied.