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Biomedical subjects

L Hunter

Publications and source records attributed to L Hunter.

At least 55 records · Page 3Linked to original sources
PubMed1993

Waiting for coronary revascularization in Toronto: 2 years' experience with a regional referral office.

OBJECTIVES: To determine the frequency of major adverse events among patients awaiting coronary revascularization; to assess the match between referring physicians' estimates of urgency, a computer-generated multifactorial urgency rating score and actual waiting times; to determine the changes in waiting times as capacity for bypass surgery increased; and to evaluate the influence of choice of procedure or operator on waiting times. DESIGN: Consecutive case series. SETTING: Greater Toronto region. SUBJECTS: All 571 patients referred to an organized referral office by cardiologists at hospitals without on-site revascularization facilities between Jan. 3, 1989, and June 30, 1991. MAIN OUTCOME MEASURES: Preoperative fatal or nonfatal myocardial infarction; proportions of patients waiting longer than the maximum period recommended for their urgency rating; mean waiting times for various subgroups; and correlations among referring physicians' urgency ratings, computer-generated multifactorial urgency scores and waiting times. RESULTS: Of the 496 patients accepted for a procedure 5 had fatal cardiac events and 3 nonfatal myocardial infarction. Events occurred three times more often in patients with left mainstem disease than in those in other anatomic categories (relative risk [RR] 3.05, 95% confidence interval [CI] 1.48 to 6.27, p = 0.03). Both the computer-generated scores and the referring physicians' scores were correlated with the actual waiting time (r = 0.46 and 0.57 respectively). Waiting times and the proportion of patients with excessive waiting times fell during the study period (p < 0.0001). However, urgent cases were much less likely to be done "on time" than those with a recommended waiting time of more than 2 weeks (RR 0.16, 95% CI 0.11 to 0.25, p < 0.0001). The mean wait for coronary artery bypass grafting (CABG) was 22.73 days if the referral office was allowed to find a surgeon or interventional cardiologist and 35.31 days if one was requested (p = 0.002 after adjustment for urgency scores). CONCLUSIONS: Death of a patient on the waiting list is uncommon in an organized referral system. Patients with left main-stem disease are at higher risk of death than those in other anatomic categories. There were significant correlations between referring physicians' ratings of urgency, multifactorial urgency scores and actual waiting times. Expansion of capacity for CABG led to shorter waiting times, but patients with unstable symptoms continued to wait longer than recommended. Requests for a specific surgeon caused significantly longer delays.

Aged↗
PubMed1993

Queueing for coronary surgery during severe supply-demand mismatch in a Canadian referral centre: a case study of implicit rationing.

Queues for in-patient surgery are commonplace in universal health care systems. Clinicians and hospitals usually manage these waiting lists with informal criteria for determining patient priority--a form of implicit rationing. To understand the workings of implicit rationing by queue, we took advantage of a natural experiment in the Canadian province of Ontario. Unprecedentedly severe supply-demand mismatch led to long waiting lists for coronary surgery [CABS] in Ontario during 1987-88. The crisis was resolved by increased funding and widespread adoption of a multifactorial clinical index for patient priority that was developed by an expert panel in 1989. Thus, we audited randomly chosen charts of patients who underwent coronary angiography at four Toronto hospitals during the crisis period, and calculated urgency scores for each case based on the multifactorial index. From 413 charts, 193 eligible patients were identified who proceeded to CABS. Waiting times did correlate with urgency ratings (r = 0.42, P < 0.0001). However, mean wait from catheterization to CABS varied among hospitals by as much as 8 weeks (P < 0.0001 after controlling for urgency scores). At the hospital with shortest queues, waiting times were twice as long for patients catheterized by cardiologists off-site vs those referred by on-site practitioners (P < 0.0001, after controlling for urgency scores); a similar form of bias was found at a second coronary surgery centre (P = 0.056, after controlling for urgency scores). Over half the patients waited longer than the maximum suggested for their category by the expert panel.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiology Service, Hospital↗
PubMed1993

Finding relevant biomolecular features.

Many methods for analyzing biological problems are constrained by problem size. The ability to distinguish between relevant and irrelevant features of a problem may allow a problem to be reduced in size sufficiently to make it tractable. The issue of learning in the presence of large numbers of irrelevant features is an important one in machine learning, and recently, several methods have been proposed to address this issue. A combination of machine learning approaches and statistical analysis methods can be used to identify a set of relevant attributes for currently intractable biological problems. We call our framework F/I/E (Focus-Induce-Extract). As an example of this methodology, this paper reports on the identification of the features of mutations in collagen that are likely to be relevant in the bone disease Osteogenesis imperfecta.

Amino Acid Sequence↗
PubMed1993

Computationally efficient cluster representation in molecular sequence megaclassification.

Molecular sequence megaclassification is a technique for automated protein sequence analysis and annotation. Implementation of the method has been limited by the need to store and randomly access a database of all the sequence pair similarities. More than 80,000 protein sequences are now present in the public databases, and the pair similarity data table for the full protein sequence database requires over 1 gigabyte of storage. In this paper we present a computationally efficient representation of groups based on a graph theory approach where sequence clusters are described by a minimal spanning tree of highest scoring similarity pairs. This representation allows a classification of N proteins to be stored in order(N) memory. The use of this minimal spanning tree representation simplifies analysis of groups, the description of group characteristics and the manual correction of artifacts resulting from false hits. The new tree representation also introduces new possibilities for artifact generation in sequence classification. Methods for detecting and removing these artifacts are discussed.

Algorithms↗
PubMed1992

Physical therapy assessment and treatment protocol for nursing home residents.

This article describes a standard protocol for assessing physical function in elderly nursing home residents. Major physical dimensions that are measured with the protocol include range of motion, muscle force, muscle reflex activity, sensation, soft tissue status, balance/coordination, and posture. A practical, functionally prioritized treatment model based on the assessment is also presented. The standardized assessment and treatment plan may be useful to the physical therapist in (1) planning and prioritizing treatment, (2) identifying when goals have been met, (3) recognizing when there is a need for treatment plan modification, and (4) educating physical therapy students in applying problem-solving skills in their treatment sessions.

Activities of Daily Living↗
PubMed1991

Perceptual characteristics of vowel and prosody production in apraxic, aphasic, and dysarthric speakers.

Narrow phonetic transcriptions and prosodic judgments were made of single-word imitations by apraxic (AOS), conduction aphasic (CA), and ataxic dysarthric (AD) speakers. AOS and AD subjects showed similar vowel error patterns, particularly predominant errors in low, tense, and back vowels, more distortions than other types of vowel errors, and predominant errors in initial position of words and in monosyllabic words. The CA subjects displayed a different vowel error pattern, notably more substitutions than distortions, more errors in polysyllabic than monosyllabic words, and more errors in noninitial than initial positions of words. Analysis of prosodic features identifiable at the single-word level (e.g., syllabic stress, juncture, and struggles to initiate or complete productions) indicated that syllabic stress errors and more difficulty initiating than completing word production were characteristic of AOS and AD but not CA subjects.

Adult↗
PubMed1991

Effect of visual display unit use on blink rate and tear stability.

In the literature, there is evidence supporting the notion that visual display unit (VDU) use decreases the blink rate and possibly reduces the stability of the precorneal tear film. In this investigation the blink rate and tear stability were measured using noninvasive techniques, in relation to VDU use. In normal healthy subjects, the results show an average 5-fold drop in blink rate during VDU use but tear stability appears to be unaffected. During VDU use a significant relation was found to exist between the interval between blinks and the stability of the precorneal tear film.

Adolescent↗
PubMed1991

The use of strategies to increase speech intelligibility in cerebral palsy: an experimental evaluation.

The effects of strategies on the intelligibility of cerebral-palsied speech were experimentally evaluated. Listeners were asked to identify words in sentences spoken by subjects whose dysarthria was rated to be either moderate or severe. Results indicated that strategies increased intelligibility and that different strategies were appropriate at different levels of severity. Use of initial letter cueing achieved the greatest gains for the more severely impaired speakers but, for the less severely impaired, the gains achieved by providing visual cues were the same as those achieved by letter cueing and could not be improved upon by repetition. Listeners' experience of dysarthric speech and the redundancy of the test sentences were also manipulated. Previous experience did not influence recognition and redundancy only appeared to have an influence at higher levels of intelligibility. The role of strategies in improving intelligibility is discussed. The results suggest that many speakers will be unable to use simple strategies to improve intelligibility to levels that may be needed for adequate information transfer.

Adolescent↗
PubMed1991

Assessing linearity the easy way.

Laboratories can comply with new Federal regulations for linearity verification by applying simple calculations and graphs to materials that are readily at hand.

Autoanalysis↗
PubMed1991

Balance function test correlates of the Dizziness Handicap Inventory.

Balance Function test data alone cannot capture the reaction that a patient has to balance system disease. The present investigation examined the relations among components of the balance function examination (electronystagmography, rotational testing, and platform posturography) and self-perceived dizziness handicap, as quantified by the Dizziness Handicap Inventory (DHI). The DHI is a 25-item self-assessment scale designed to quantify the functional, emotional, and physical effects of dizziness and unsteadiness. The DHI was administered to 367 patients seen consecutively for balance function evaluations. The results indicated that the largest proportion of significant correlations existed between DHI and the sensory organization subtests of platform posturography. Further, greater perceived handicap was documented for patients with (1) spontaneous nystagmus and (2) decreased postural stability quantified by evaluating the inter-relations among vestibular, visual, and proprioceptive systems (posturography).

Activities of Daily Living↗
PubMed1990

Perceptual characteristics of consonant production by apraxic speakers.

Single-word repetitions by 4 brain-damaged adults with apraxia of speech (AOS) but without concomitant aphasia were transcribed using a standard narrow phonetic transcription system. Analysis of consonant productions yielded a profile of AOS slightly different from the traditionally accepted one. Among the results was the atypical finding that consonant distortions exceeded all other error types including sound substitutions. In addition, errors predominated in the medial position of words, and monosyllabic words had approximately the same error rate per number of consonants as did multisyllabic words. Results are discussed with reference to previous perceptual descriptions of AOS and in relationship to Broca's aphasia. Results are also interpreted relative to linguistic and motoric components of speech production models.

Aged↗
PubMed1990

Site-specific integration by adeno-associated virus.

Cellular sequences flanking integrated copies of the adeno-associated virus (AAV) genome were isolated from a latently infected clonal human cell line and used to probe genomic blots derived from an additional 21 independently derived clones of human cells latently infected with AAV. In genomic blots of uninfected human cell lines and of primary human tissue, each flanking-sequence probe hybridized to unique bands, but in 15 of the 22 latently infected clones the flanking sequences hybridized not only to the original fragments but also to a total of 36 additional species. AAV probes also hybridized to 22 of these new bands, representing 11 of the 15 positive clones, but never to the fragment characteristic of uninfected cell DNA. From these data we conclude that the AAV genome preferentially integrates into a specific region of the cellular genome. We have determined that the integration site is unique to chromosome 19 by somatic cell hybrid mapping, and this sequence has been isolated from uninfected human DNA.

Cell Line↗
PubMed1989

Anthrax.

Explore the source record for details and available documents.

Adult↗
PubMed1989

Fax technology: elegant solution for lab.

A shot in the arm from fax technology has invigorated a cumbersome manual laboratory system at Baptist Medical Center in Kansas City, Mo. Using a hot, proliferating technology, BMC developed a system for lab ordering/results reporting that interfaces to the LIS mainframe, links to stations on and offsite, and is less costly than other alternatives.

Clinical Laboratory Information Systems↗
PubMed1989

Epidemiologic survey of bovine diseases in Suriname.

A seroepidemiologic survey of cattle diseases was undertaken in Suriname in 1985 to help assess the livestock disease situation in that country. The six diseases covered by the survey were bovine coronavirus infection, bovine rhinotracheitis, bovine virus diarrhea, brucellosis, parainfluenza-3 infection, and respiratory syncytial virus infection. The results indicated relatively low prevalences of these diseases compared to the prevalences found in most developed countries. The reasons for this are uncertain, but the finding suggests that the cattle population in Suriname could lack extensive exposure to these diseases and so could be highly susceptible to them. In addition, the evident need for more thoroughgoing survey data points up the need to establish a continuous animal data health monitoring system in Suriname--as well as in other developing countries where there is a need to objectively assess the livestock disease picture.

Animals↗