Transference and countertransference contributions toward understanding the phenomenon of institutionalization of schizophrenic patients.
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Autistic Disorder↗
Biomedical subjects
R St John
Publications and source records attributed to R St John.
Transfusion-transmitted malaria in Canada.
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Adult↗
Judgements of visual precedence by strabismics.
Strabismus induced early in the life of cats results in disruption of the normal development of the posterior corpus callosum. In human strabismic amblyopic subjects a similar disruption in callosal development may cause poor interhemispheric integration of simple visual information. To examine this possibility judgements of visual target onset precedence were made for targets presented in bilateral and unilateral viewing conditions using a method of constants psychophysical procedure. In one condition, with targets presented in opposite visual fields requiring integration between the two hemispheres, the subjects having strabismic amblyopia had significantly larger just noticeable difference values (JNDs) than those found for the non-strabismic controls. In a second condition, with targets presented within a visual field requiring integration within only a single hemisphere, the JNDs for the two groups were not significantly different. The results suggest that strabismic amblyopes have poor integration of visual information between the cerebral hemispheres, and that this reflects disruptions in the development of the posterior corpus callosum.
Adult↗
Practices in the Prevention of Venous Thromboembolism.
Objective: The objective of this study was to determine the proportion of Massachusetts Medicare patients who received prophylaxis for venous thromboembolism following colectomy, hysterectomy, or total hip arthroplasty. Sample frame: All 90 Massachusetts acute care hospitals. Time frame: 1 April through 30 September, 1994. Target population: Patients discharged with an International Classification of Disease (ICD-9-CM) discharge diagnostic code (recorded in the Massachusetts Medicare Claims Database) for colectomy, hysterectomy, or total hip arthroplasty were used to identify the target patient population. Sample population: 1,397 patients randomly selected from the target population, including 467 total hip arthroplasties, 474 colectomies, and 456 hysterectomies. Data extraction: Medical records were reviewed by trained nurse abstractors who collected information on the use of prophylaxis for venous thromboembolism. Results: Prophylaxis for venous thromboembolism was employed by surgeons practicing in Massachusetts hospitals in 93% of total hip arthroplasty cases (regional variation 85-98%), 84% of colectomies (regional variation 57-93%), 66% of hysterectomies (regional variation 35-71%), and in 87% of the subset of 111 hysterectomies with malignancy (regional variation 25-100%). Conclusions: The results of this statewide study demonstrated significant regional and hospital-to-hospital variation in the use of prophylaxis for venous thromboembolism following major surgery. A lower rate of prophylaxis use was observed in hospitals with fewer than 200 beds and in hospitals that did not have teaching programs. Hospitals with below-average rates of prophylaxis were targeted for intensive quality improvement interventions.
Journal Article↗
How current is your travel health information?
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Canada↗
Contrast detection and orientation discrimination thresholds associated with meridional amblyopia.
Humans who have astigmatism resulting in meridional amblyopia exhibit deficits in performing visual tasks at or near detection thresholds. However, there is mounting evidence supporting the idea that performance at threshold may not reliably predict visual capabilities at supra-threshold levels of stimulation. In this study the threshold and supra-threshold performance of six meridional amblyopes were compared. A difference in the pattern of oblique effects was observed between contrast detection thresholds and supra-threshold orientation discriminations. This suggests there exists an independence between populations of neurons subserving contrast detection and the discrimination of visual stimuli. Meridional amblyopia may primarily involve a degradation in those mechanisms subserving visual contrast detection. Populations of cells subserving supra-threshold abilities such as orientation discrimination remain relatively unaffected in humans exhibiting meridional amblyopia.
Amblyopia↗
Mechanical ventilation with or without daily changes of in-line suction catheters.
The purpose of this study was to determine the safety and cost-effectiveness of not routinely changing in-line suction catheters for patients requiring mechanical ventilation. Patients were randomly assigned to receive either no routine in-line suction catheter changes (n = 258) or in-line suction catheter changes every 24 h (n = 263). The main outcome measure was the incidence of ventilator-associated pneumonia. Other outcomes evaluated included hospital mortality, acquired organ system derangements, duration of mechanical ventilation, lengths of intensive care and hospital stay, and the cost for in-line suction catheters. Ventilator-associated pneumonia was seen in 38 patients (14.7%) receiving no routine in-line suction catheter changes and in 39 patients (14.8%) receiving in-line suction catheter changes every 24 h (relative risk, 0.99; 95% CI, 0.66 to 1.50). No statistically significant differences for hospital mortality, lengths of stay, the number of acquired organ system derangements, death in patients with ventilator-associated pneumonia, or mortality directly attributed to ventilator-associated pneumonia were found between the two treatment groups. Patients receiving in-line suction catheter changes every 24 h had 1,224 catheter changes costing a total of $11,016; patients receiving no routine in-line suction catheter changes had a total of 93 catheter changes costing $837. Our findings suggest that the elimination of routine in-line suction catheter changes is safe and can reduce the costs associated with providing mechanical ventilation.
Adult↗
Patient transport from intensive care increases the risk of developing ventilator-associated pneumonia.
STUDY OBJECTIVE: To determine whether patient transport out of the ICU is associated with an increased risk of developing ventilator-associated pneumonia. DESIGN: Prospective cohort study. SETTING: ICUs of Barnes-Jewish Hospital, a university-affiliated teaching hospital. PATIENTS: Five hundred twenty-one ICU patients requiring mechanical ventilation for > 12 h. INTERVENTION: Prospective patient surveillance and data collection. MEASUREMENTS AND RESULTS: The primary outcome measure was the development of ventilator-associated pneumonia. A total of 273 (52.4%) mechanically ventilated patients required at least one transport out of the ICU while 248 (47.6%) patients did not undergo transport. Sixty-six (24.2%) of the transported patients developed ventilator-associated pneumonia compared with 11 (4.4%) patients in the group not undergoing transport (relative risk=5.5; 95% confidence interval [CI]=2.9 to 10.1; p<0.001). Multiple logistic regression analysis demonstrated that a preceding episode of transport out of the ICU was independently associated with the development of ventilator-associated pneumonia (adjusted odds ratio=3.8; 95% CI=2.6 to 5.5; p<0.001). Other variables independently associated with the development of ventilator-associated pneumonia included reintubation, presence of a tracheostomy, administration of aerosols, and male gender. CONCLUSIONS: We conclude that patient transport out of the ICU is associated with an increased risk for the development of ventilator-associated pneumonia.
APACHE↗
Bronchial dilatation in patients with HIV infection: CT assessment and correlation with pulmonary function tests and findings at bronchoalveolar lavage.
OBJECTIVE: Symptoms of airway disease occur in patients infected with HIV, and bronchiectasis has been reported in patients with AIDS. We evaluated thin-section thoracic CT scans in HIV-positive individuals for bronchial dilatation and correlated imaging findings with pulmonary function abnormalities and findings at bronchoalveolar lavage (BAL). SUBJECTS AND METHODS: Sixty-one subjects, 50 of whom were HIV-positive and 11 of whom were HIV-negative, underwent thin-section CT, BAL, and pulmonary function tests. Two radiologists evaluated the CT scans on two separate occasions for bronchial dilatation in each lobe. BAL and pulmonary function test data in the subjects with bronchial dilatation were compared with such data in subjects with normal bronchi seen on CT scans. RESULTS: Eighteen of the 50 HIV-positive subjects and none of the HIV-negative subjects had bronchial dilatation revealed by CT. Subjects with bronchial dilatation revealed by CT had significantly higher BAL neutrophil counts (p = .014) and significantly lower diffusing capacity (p = .003) than did subjects with normal bronchi revealed by CT. CONCLUSION: Bronchial dilatation is commonly revealed by CT scans of HIV-positive individuals. The association of elevated levels of BAL neutrophils and decreased diffusing capacity with bronchial dilatation that we found in this study suggests that the neutrophil may be associated with airway damage and lung destruction in patients who are infected with HIV.
Adult↗
Human plague in India, August-October, 1994.
As of 9 October, the total number of fatalities in India due to plague was 55 (52 from Surat city and 3 from New Delhi). Reasons for the low case-fatality ratio remain to be determined and will require more detailed and reliable clinical and laboratory information. Additional studies into the patterns of transmission in the infected areas are underway or anticipated. By 14 October reports of both suspect and confirmed cases had decreased. The area around the Beed district in the state of Maharashtra was also declared as "infected" under the definition of the International Health Regulations. A WHO expert committee has been in the affected areas and detailed reports are anticipated.
Disasters↗
Measurement of visual aftereffects and inferences about binocular mechanisms in human vision.
There is conflicting evidence concerning the characteristics of binocular channels in the human visual system with respect to the existence of a 'pure' binocular channel that responds only to simultaneous stimulation of both eyes. Four experiments were conducted to resolve these discrepancies and to evaluate the evidence for the existence of such an exclusive binocular channel. In the first three studies, tilt aftereffects were measured after monocular adaptation. The relative sizes of the direct, interocularly transferred, and binocular aftereffects were not influenced by the configuration of the adapting pattern (experiment 1), or by the eye used for adaptation (experiment 2). There were also consistent interobserver differences in the relative sizes of the aftereffect seen after monocular adaptation (experiment 3). Taken together, these data raise questions about the appropriateness of a monocular adaptation paradigm for evaluating the presence of a pure binocular channel in observers with normal binocular vision. In experiment 4, in which the paradigm of alternating monocular adaptation was used, data were obtained that are consistent with the presence of a pure binocular channel.
Adolescent↗
On the evidence for a 'pure' binocular process in human vision.
Wolfe (1986, Psychol. Rev. 93, 269-282) proposed a model of human binocular vision based on the assumption of two functionally distinct classes of binocular neuron. These neurons may be regarded as logical AND and OR gates. In the present paper we assess the evidence relevant to this assumption. We find that while both types of binocular neuron have been described in the cortex of cat and monkey, there is no indication that they form functionally separate populations. Critical analysis of the psychophysical evidence for AND and OR channels in human vision suggests that much of the data presented in favor of an AND channel is subject to alternative interpretations. We conclude that the available data are not consistent with the existence of separate channels as proposed by Wolfe.
Adaptation, Ocular↗
Changes in perceived contrast of suprathreshold gratings as a function of orientation and spatial frequency.
Orientation anisotropy for suprathreshold gratings of different spatial frequencies was measured using a contrast matching procedure. Observers matched the contrast of sine-wave gratings of various orientations to a vertical reference grating set at different reference contrasts. At threshold, the size of the anisotropy increased with spatial frequency, confirming previous results. When the reference grating contrast was set above threshold, the anisotropy declined, and eventually disappeared for gratings of medium spatial frequencies. At higher spatial frequencies, although the relative anisotropy became smaller, it did not disappear within the range of contrasts used in this study. For medium, but not for high spatial frequencies, the data are consistent with Kulikowski's (1976) model of effective contrast constancy.
Contrast Sensitivity↗
The reliability of estimates of interhemispheric transmission times derived from unimanual and verbal response latencies.
In this study, the reliability of estimates of interhemispheric transmission times derived from verbal and unimanual responses was assessed. Responses were made to presentations of lateralized light flashes in a series of 20 experimental sessions, with responses being made to stimuli presented at three different retinal eccentricities. The reliability of estimates of interhemispheric transmission across 20 experimental sessions was generally poorer for verbal compared to unimanual responses. This was particularly true for stimuli presented close to the centre of the visual field. In addition, for unimanual response conditions, estimates of interhemispheric transmission times for the female subjects were longer in duration and exhibited poorer reliability than estimates found for the male subjects. In the verbal response conditions, there were no differences between the mean durations of the estimates found for the male and female subjects. The results suggest that for centrally located stimulus presentations, verbal responses do not produce reliable estimates of interhemispheric transmission time. This relatively poor reliability across experimental sessions may account for the mixed results seen in previous studies which have used verbal reaction times to estimate interhemispheric transmission time. The collection of unimanual responses to lateralized visual stimulus presentations is likely the best method of estimating interhemispheric transmission time in normal man.
Adult↗
Interhemispheric transmission delays in human strabismics.
Experimentally induced strabismus in cats and monkeys leads to a variety of anatomical, physiological, and perceptual deficits. Given the similarities between the perceptual deficits of human strabismics and those of animal models, it is reasonable to suggest similarities in the underlying anatomical and physiological deficits. In cat, one anatomic anomaly associated with strabismus is a disruption of the normal development of the posterior corpus callosum. The present study provides evidence that interhemispheric transmission in human strabismics may be disrupted also. Simple unimanual reaction times were used to examine the transmission of information through callosal fibres. Estimates of cross-callosal transmission time for strabismics were consistently longer than for individuals with no history of strabismus. This difference was found only when targets were presented within 5 degrees of the fixation point. The results suggest that human strabismics may have abnormalities in those callosal fibres which are involved in the interhemispheric transmission of visual information.
Adolescent↗
Eye movements of human albinos.
Albino mammals are known to suffer from misrouted optic projections and there is a growing body of evidence suggesting that human albinos have similar aberrant anatomical pathways. The present study examined the possible consequences of such aberrant pathways on the oculomotor performance of five adult human albinos. Optokinetic nystagmus to drifting grating patterns and pursuit eye movements were measured. The subjects' congenital nystagmus was also measured under different conditions of gaze position and ambient room illumination. Two of the subjects showed clear instances of an inversion in the optokinetic response and there were probable inversions observed for a third subject. The magnitude of the optokinetic nystagmus was appropriate for the rate of pattern drift, but inverted in direction. In all cases smooth pursuit was severely impaired, but reversals of the appropriate direction of pursuit eye movements were not observed. Changes in the congenital nystagmus under conditions of light and darkness were found for four of the five subjects and varied greatly between subjects. The results suggest that human albinos share many of the oculomotor deficits found in other albino species.
Albinism↗
A model for predicting clinically relevant group differences of open-response tests.
A comparison is made between testing for differences in group means and testing to assign an individual subject to one of two populations. A distinction is made between sample means of speech-discrimination tests which are statistically different and clinically useful speech-discrimination tests for properly classifying an individual. The probabilities of misclassification are discussed.
False Negative Reactions↗