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Biomedical subjects

J Walters

Publications and source records attributed to J Walters.

At least 73 records · Page 4Linked to original sources
PubMed1990

Femoral shaft fractures treated by Ender nails using a trochanteric approach.

We describe the use of Ender nails for the internal fixation of femoral shaft fractures by a closed technique via the greater trochanter and report the treatment of 100 patients with 106 fractures, of which 88 were reviewed 12 months or more after operation. There was primary union in 85 fractures (96.6%) and significant angulation, rotation or leg length discrepancy in eight (9%). We discuss the principles of management which we have evolved.

Bone Nails↗
PubMed1989

Oscillatory potentials of X-linked carriers of congenital stationary night blindness.

ERG oscillatory potentials (OPs) were recorded from obligate carriers of CSNB and from age-matched normal subjects. The OPs were recorded under four stimulus conditions and were analyzed in the time and frequency domains. The results, first of all, provide confirmation of the previous report that the OP amplitude is reduced in carriers. Second, the results show that, of four stimulus conditions examined, the best condition for discriminating the carriers and normal subjects was when the flash was blue and the eye was dark-adapted. Third, the results show that, in the frequency domain, optimal discrimination occurs when examining the power content of the OP at a center frequency of about 130 Hz using a 70 Hz bandwidth window. In the time domain, optimal discrimination occurs when examining the amplitude of the third peak of the response.

Electroretinography↗
PubMed1988

Traumatic atlanto-axial subluxation.

Traumatic atlanto-axial subluxation is a rare injury which may not be revealed on routine radiographs, especially when there is muscle spasm. We report on seven patients with atlanto-axial subluxation as a result of neck injury; only two of them had significant head injuries. Three patients presented with a neurological deficit attributable to the injury, one immediate and two with delayed onset. Traumatic atlanto-axial instability, occurring in an otherwise healthy patient, has a potential for neurological disaster; early consideration of operative treatment is indicated.

Adult↗
PubMed1987

Differentiation of girls at risk of early pregnancy from the general population of adolescents.

The purpose of this study was to examine two psychological characteristics (locus of control and purpose in life) that have been associated with early pregnancy. The characteristics were examined first in samples drawn from a general population of adolescents and then in samples of ever-pregnant and never-pregnant adolescents. Ever-pregnant girls differed neither from the general population of adolescents nor from the matched sample of never-pregnant girls on the two psychological dimensions. Alternatives for conceptualizing risk are proposed.

Adaptation, Psychological↗
PubMed1987

Combined anti-muscarinic and H2 receptor blockade in the healing of refractory duodenal ulcer. A double blind study.

The purpose of this study was to determine if pirenzepine and cimetidine given together was superior to cimetidine alone in inducing healing of refractory duodenal ulcers which remained unhealed after treatment with cimetidine or ranitidine for at least eight weeks. One hundred and thirty one patients from six centres were randomised to receive either cimetidine (C) 800 mg daily or cimetidine 800 mg plus pirenzepine (C + P) 100 mg daily under double blind conditions for six weeks. The healing rate was similar in both groups, irrespective of the method of calculation. On an intent-to-treat analysis, healing was: C 66%, C + P 57%, and amongst the patients who completed treatment, healing was 70% in both groups. Patients on C and on C + P experienced a similar decrease in daytime and in night time pain. Side effects of treatment, notably dry mouth and blurred vision, were reported more often by patients on combination therapy. Combined treatment with cimetidine plus pirenzepine in patients with refractory duodenal ulcer is unlikely to be beneficial.

Adult↗
PubMed1987

Relationships between minute ventilation, oxygen uptake, and time during incremental exercise.

It has recently been reported that blood and muscle lactate increased exponentially during incremental exercise, casting some doubt upon the concept of 'anaerobic threshold'. To gain further insight into this controversy, we examined the relationships between minute ventilation (VE), time and oxygen uptake (VO2) in normal subjects during incremental exercise. During exercise, the relationship of VE to either time of exercise or to VO2 appeared curvilinear; VE was reliably described as an exponential function (y = axb + c) of both time of exercise (r2 = 0.96) and VO2 (r2 = 0.92). We also compared variables from 30-second incremental tests with variables obtained from quasi-steady-state incremental tests using cycle and treadmill ergometry. With the exception of heart rate, variables measured at maximum exercise were similar during short-duration and quasi-steady-state incremental tests. These data support the ideas that: there is no abrupt change in metabolism and oxygen availability during progressive exercise, and results of rapid incremental and quasi-steady-state exercise tests are generally comparable in normal individuals.

Adult↗
PubMed1984

Establishing generative yes/no responses in developmentally disabled children.

We evaluated the effects of two procedures for teaching four developmentally disabled children to respond yes/no appropriately. During baseline, tutoring was conducted in which five known items were individually presented with the question, "Is this a ----?", followed either by access to requested items or by remedial prompting contingent on responding. When tutoring did not improve performance, instruction was embedded in the regular classroom activities. In this condition, items requested by students were either presented or withheld on the basis of their response to the question, "Do you want ----?". Increases in correct responding were confirmed by a multiple-baseline design across all four students and were maintained with the introduction of new items. However, generalization to "Is this a ----?" questions did not occur in the tutoring setting until specifically programmed. Subsequently, students also demonstrated appropriate yes/no responding to questions involving actions, possession, and spatial relations.

Child↗
PubMed1983

A comparison of incremental exercise tests during cycle and treadmill ergometry.

We evaluated a short-duration maximum exercise test by comparing a 15-s incremental exercise protocol with a 1-min incremental method. Twenty normal men and women were studied using cycle and/or treadmill ergometry. In subjects tested on both exercise devices, anaerobic threshold and maximal oxygen uptake (VO2max) were higher for both protocols on the treadmill than on the cycle ergometer (P less than 0.001). However, when the 15-s and 1-min tests were compared using the same device (treadmill or cycle), there were no significant differences between protocols in anaerobic threshold or maximum exercise values of minute ventilation, respiratory rate, tidal volume, VO2max, oxygen pulse, and peak expiratory flow rate. Linear regression analyses indicated differences between the 15-s and 1-min protocols when cardiopulmonary measurements were related to power; however, the two protocols were comparable when cardiopulmonary data were related to oxygen uptake. Comparisons between protocols or between exercise devices were not systematically different in large vs small individuals, or in men vs women. Short-duration incremental exercise tests appear to be reliable, practical methods for assessing exercise performance in normal individuals.

Exercise Test↗