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Biomedical subjects

M Guay

Publications and source records attributed to M Guay.

At least 19 recordsLinked to original sources
PubMed1999

The effects of different knowledge of results spacing and summarizing techniques on the acquisition of a ballistic movement.

The present study crossed three knowledge of results summarizing techniques (single-trial KR, summary KR, and average KR) with two spacing conditions (KR on every fifth trial-20%- and KR on every trial-100%). Participants (n = 10 per group) performed 80 acquisition trials of a ballistic movement task involving both a temporal and spatial goal, followed by 30 immediate (10 min) and 30 delayed (2 days) no-KR transfer trials. For the spatial goal, performance was less accurate (absolute constant error) for the 20% spacing condition than the 100% condition during acquisition, but more accurate during delayed transfer. No effects were significant for variable error. For the temporal goal, performance was more accurate for the summary and average conditions than the single-trial KR condition; however, this effect was only present within the 20% spacing condition and only during Block 1 of acquisition. A similar effect held for variable error as well, except that the effect persisted for acquisition and transfer. It was concluded that the spacing of KR is more influential in promoting spatial accuracy than the summarizing of KR.

Adult↗
PubMed1996

Performance of the 'unaffected' upper extremity of elderly stroke patients.

BACKGROUND AND PURPOSE: The main objective of this study was to compare the sensorimotor performance of the unaffected upper extremity (UE) of elderly stroke patients with that of healthy elderly people. METHODS: The group of stroke patients was composed of 43 hemiplegic/paretic subjects who had had a cerebrovascular accident at least 6 months earlier. They were > or = 60 years old, were right-handed before the stroke, had visual perception within normal limits, and showed no major cognitive impairments. A group of 43 healthy subjects matched for dominance, age, and sex was used for comparison. The main parameters of the performance of the unaffected UE of the stroke subjects and of the same side of the healthy subjects were measured with valid, reliable instruments. Some variables potentially related to the unaffected UE were also measured: affected UE motor function, functional independence, length of time since the stroke, self-perceived health status, activity level, and hand anthropometry. RESULTS: Statistical analyses showed significant deficits in the unaffected UE of hemiplegic/paretic subjects compared with normal subjects with regard to the following parameters: gross manual dexterity, fine manual dexterity, motor coordination, global performance, and kinesthesia (P < .01 to P < .0001). No significant clinical or statistical difference was found for grip strength (P < .81), static and moving two-point discrimination (P = .21 and P = .12), or touch/pressure threshold (P < .91). CONCLUSIONS: Many factors (frequency of use of the unaffected hand, sensorimotor interaction tasks, severity of the deficits in corticifugal projections, and deficits in postural stabilization) could interact to provide the clinical picture obtained in the present study.

Aged↗
PubMed1988

Weber's law for the reproduction of temporal information.

The main purpose of this research was to determine the numeric values of Weber's fraction when subjects were required to estimate temporal durations of 1, 3, 5, 7, and 9 sec. under the method of reproduction. The results provided evidence in support of a constant coefficient of proximity for time estimation of approximately 14.5%.

Adult↗
PubMed1988

Effect of interpolated temporal activity on temporal short-term memory.

The purpose of this research was to determine the retroactive interference effects of a single interpolated task (i.e., one temporal duration) on the retention of a criterion duration. This research is of interest because the mnemonic structure of temporal information of different durations is uncertain. Previous research has indicated that there might be a difference in structure for durations of 1 and 4 sec., although the results are inconsistent. Thus, two criterion durations of 1 and 4 sec. and five interpolated durations (i.e., 60%, 80%, 100%, 120%, and 140% of the duration of the criterion) were utilized under the method of reproduction. In addition, subjects were instructed to use either a counting strategy or none (referred to as conscious time estimation) to facilitate the retention of the temporal information. Recall was less variable when using a counting strategy than not and when estimating 1 sec. than 4 sec. However, there was no effect of interpolated activity when comparing performance across different interpolated conditions (no interpolated activity). Apparently, one interpolated duration is not sufficient to produce structural interference with a single criterion duration.

Cues↗
PubMed1987

Photolysis and ozonolysis of (iso)desmosine-containing crosslinked peptides from porcine aorta elastin.

This report describes the use of photolysis and ozonolysis as a means of achieving complete cleavage of the pyridinium ring of (iso)desmosine in crosslinked elastin peptides. Although photolysis leads to the opening of the ring with concomitant formation of lysine, the peptide chains remain attached. Subsequent ozonolysis is able to completely achieve the cleavage of the rest of the ring skeleton, thus leading to the separation of the peptide chains. Formation of new amino acids, i.e. alpha-aminoadipic and glutamic acids, is emphasized. Localization of these amino acids within the released peptides should be of help in structural investigations on the crosslinking zones involving either isodesmosine or desmosine. However, other amino acids such as tyrosine and phenylalanine are sensitive to this procedure and side reactions occur which are responsible for peptide bond cleavage with the formation of breakdown products.

Amino Acids↗
PubMed1987

An examination of self-pacing procedures in human time estimation.

The main purpose of the present research was to investigate the role of self-pacing trial procedures in time estimation. Auditory durations of 1, 4, and 8 sec. were estimated by 12 subjects under the method of reproduction. Different features of performance were investigated using several dependent variables. When left to themselves, subjects chose a relatively short intertrial interval, the duration of which did not differ across the three criterion durations. This finding seemed best explained as an attempt by the subjects to minimize boredom and maximize alertness. Also, subjects waited for a short time before reproducing the criterion duration, and again this period did not differ across the three criterion durations. A significant relationship was found between the duration of the self-paced intertrial interval and self-paced retention interval for all criterion durations. It appeared that subjects were attempting to maximize their time-estimation performance by either minimizing the retention interval or by developing a trial-interval rhythm. Finally, subjects were more variable in their estimates as the criterion duration increased.

Adult↗
PubMed1987

Counting strategies and assimilation effects in short-term retention of temporal information.

The purpose of the present research was to examine proactive interference in general and assimilation effects (i.e., shifts in constant error caused by prior responses) in particular, when subjects used covert counting to aid their retention of the temporal information. Visually presented durations of 1, 4, and 8 sec. were estimated by 18 subjects under the method of reproduction. Three retention intervals (i.e., immediate, 15, and 30 sec.) and three intertrial intervals (i.e., immediate, 15, and 30 sec.) were employed. Analysis of constant error provided no indication that proactive interference was operating in the retention of temporal information as there was no increase in error across trials, no increase in error for longer retention intervals, and no interaction between trials and retention intervals. Also, there was no change in variable error as the retention intervals lengthened for any temporal duration except for the 4-sec. criterion. Finally, the rate of counting (counting units/sec.) was different across the durations to be remembered. The major conclusion of the present research was that counting greatly facilitates retention of temporal information as compared to retention without such a time-aiding strategy.

Attention↗
PubMed1986

Proactive interference and intertrial interval in short-term retention of temporal visual information.

The main purpose was to examine the role of proactive interference in temporal short-term memory when subjects experienced time under a conscious cognitive strategy for time estimation, made without time-aiding techniques. Visual durations of 1, 4, and 8 sec. were estimated by 18 subjects under the method of reproduction. Three retention intervals were used: immediate reproduction, 15, and 30 sec. of rest. The three intertrial intervals were immediate, 15, and 30 sec. Constant error was used as an index of bias. The constant errors provided no indication that proactive interference was operating in temporal short-term memory. The lack of proactive interference was not associated with intertrial intervals; even when the intertrial intervals were shortened to 1 sec. no proactive interference was observed. Variable error was used to evaluate effects of forgetting. The variable errors for the 4- and 8-sec. durations seemed amenable to a trace-decay explanation.

Attention↗
PubMed1985

A double blind study of vitamin B6 in Down's syndrome infants. Part 1--Clinical and biochemical results.

Nineteen patients with Down's syndrome participated in a double blind study of the clinical effects of pharmacological doses of vitamin B6 administration, starting under 8 weeks of age and continuing until 3 years of age. Ten patients received the vitamin and nine the placebo. In Part 1 of this study, no statistically significant differences were found between the two groups in mental age, height, weight, cranial circumference or tongue protrusion. A study of side effects conducted on a larger open population found vitamin B6 to be relatively safe when administered over long periods of time with photosensitive blisters as the major complication.

Blister↗
PubMed1985

Photolysis and ozonolysis of desmosine and elastolytic peptides.

This paper describes the combined effects of photolysis and ozonolysis upon the main interchain crosslinks of elastin, desmosine and isodesmosine. Photolysis of purified (iso)desmosines in solution leads to the cleavage of the pyridinium rings to give lysine and an analogue of glutaconic aldehyde which is deformylated to a stable compound absorbing at 242 nm. This photoproduct is subsequently fragmented by ozone into glutamic, alpha-aminoadipic and possibly alpha-amino-delta-oxocaproic acids. However the yields of these different compounds are very low because we observed that numerous competing side reactions (polymerisation, recyclisation) accompany the photoozonolytic decomposition of the pyridinium rings of free (iso)desmosines. The results are clearer when reticulated elastolytic peptides are photoozonolysed. The (iso)desmosines, covalently linked in these peptides, are cleaved into lysine, glutamic and alpha-aminoadipic acids (in a ratio 2:1) with yields corresponding to 80-90% of those expected from the decomposition of the (iso)desmosines originally present in the peptide fraction. We have also observed that ozonolysis alone degraded another crosslink present in these peptides, the aldol condensation product, resulting in the production again of glutamic and alpha-aminoadipic acids in amounts consistent with the known concentrations of this particular crosslink in elastin. Finally we noted that the complete photoozonolytic degradation of the (iso)desmosines present in a semi purified reticulated elastolytic fraction resulted in a shift of the size distribution of these peptides toward lower values. It is not certain however that this shift, indicative of a freeing of the polypeptide chains from their original three dimensional network, is due uniquely to the cleavage of the (iso)desmosines. Indeed we have observed that tyrosine and phenylalanine were also degraded during photoozonolysis. Not knowing the mechanism of this degradation it is impossible to rule out the possibility that concomitant cleavages of peptide bonds did occur.

Amino Acids↗
PubMed1985

Drug information services provided through a critical care satellite pharmacy.

In January, 1982, a satellite pharmacy began operating in the medical and coronary intensive care units of the Health Sciences Centre in Winnipeg. This program, which has been described in detail elsewhere, provides 24 hour on-site coverage. In addition to total unit dose and intravenous admixture services the pharmacist also monitors drug therapy and provides drug information to other health professionals in the area. With the extended hours of coverage and ready accessibility of the pharmacist it was anticipated that utilization of clinical pharmacy services would increase. As one means of assessing whether this did in fact occur, all drug information provided by the pharmacist, whether solicited or unsolicited, was recorded and tabulated each month for the first year of operation of the satellite pharmacy. This report presents the results of the data analysis.

Centralized Hospital Services↗
PubMed1985

[Paroxysmal junctional reciprocal tachycardia and fetoplacental anasarca].

Foeto-placental anasarca was diagnosed at 34 weeks gestation in a patient with acute hydramnios. Foetal tachycardia at 300 bpm was recorded. This obstetrical problem led to the birth of a premature baby with generalised oedema, for which the only apparent cause was the tachycardia. This was identified as a paroxysmal junctional reciprocating tachycardia, initiating on atrial extrasystolic echos, terminating on R waves, with lengthening of the PR interval at the onset of tachycardia, without acceleration of the sinus rate and P'R = RP'. Paroxysmal junctional reciprocating tachycardia in utero was responsible for congestive cardiac failure and foeto-placental anasarca. The cardiac failure was treated by foetal delivery, artificial respiration and digoxin. The association of digoxin-disopyramide reduces the frequency of attacks of tachycardia and treatment may be stopped after one year's follow-up.

Edema↗
PubMed1984

Rehearsal of temporal visual information.

This study compared the short-term retention characteristics of temporal information when subjects experienced time under either subject-defined or experimenter-defined rehearsal. Subjects were presented visual durations of 1 and 4 sec. and then required to reproduce these durations following a 15-sec. retention interval. To help maintain the durations in memory, subjects were asked to use either a conscious cognitive strategy or a mental counting strategy. It was predicted that experimenter-defined rehearsal would show less forgetting, as measured by variable error, but this prediction was not supported. There also was no evidence of any response bias or context effects in the temporal reproductions. These results were compared with two previous studies that utilized similar cognitive strategies.

Adult↗
PubMed1983

Immediate reproduction of temporal information under four cognitive strategies.

The main purpose was to determine the retention characteristics of temporal information when subjects experienced time under a retention interval of immediate reproduction and various cognitive strategies for time estimation. Four levels of cognitive strategy were used, viz., conscious, mental counting, counting aloud without auditory cues, and counting aloud with auditory cues. The latter three cognitive strategies were experimenter-defined, time-aiding techniques. Subjects were instructed to refrain from employing time-aiding techniques under a conscious cognitive strategy for time estimation. Visual durations of 1, 2, and 4 sec. were estimated by 12 subjects under the method of reproduction. Two measures of performance were computed, viz., variable and constant errors. The general conclusions were: (a) the effectiveness of mental counting, counting aloud without auditory cues, and counting aloud with auditory cues as cognitive strategies over conscious cognitive strategy in terms of variability depends on the duration used, and (b) in terms of accuracy and variability an increase in the number of cues under time-aiding techniques does not necessarily produce better performance.

Adult↗