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Biomedical subjects

Louise Roy

Publications and source records attributed to Louise Roy.

6 recordsLinked to original sources
PubMed2006

The cognitive validity of the Script Concordance Test: a processing time study.

BACKGROUND: According to the theory on which the Script Concordance Test (SCT) is based, scripts contain expectations on features that are associated with each illness and about the range of values that are typical, atypical, or incompatible. PURPOSE: To document the construct validity of the SCT, we investigated the theory prediction that once a script is activated, new incoming information (e.g., additional clinical features) is processed faster if it is typical for that script than if it is atypical. If it is incompatible, processing time falls in between. METHODS: We presented 2 groups of participants (30 fourth-year medical students and 30 full-time geriatricians) with 64 clinical vignettes (divided over 5 types of prevalent clinical presentations in geriatrics), each accompanied by a diagnostic hypothesis aimed to instantiate an appropriate script. Next, we presented a new finding, which could be typical, atypical, or incompatible given the hypothesis. Participants had to decide as quickly and accurately as possible whether the new finding increased, decreased, of did not affect the likelihood of the diagnostic hypothesis. We administered the test on a computer. The dependent variable was processing time. We analyzed data with a repeated measure 2 x 3 analysis of variance. RESULTS: Typical information was processed faster than atypical and incompatible information (M = 10.6 sec vs. 19.2 sec and 16.4 sec, respectively; p lt; .001 for both). Incompatible information was processed faster than atypical information (16.4 sec vs. 19.2; p < .001). There was no significant difference between the groups of geriatricians and students. CONCLUSION: It is possible to predict what kind of information will be processed faster depending of the typicality and compatibility of clinical data for given hypotheses. Results support SCT construct validity.

Clinical Clerkship↗
PubMed2003

Amino-terminal form of parathyroid hormone (PTH) with immunologic similarities to hPTH(1-84) is overproduced in primary and secondary hyperparathyroidism.

BACKGROUND: To separate non-(1-84)parathyroid hormone [non-(1-84)PTH] from PTH(1-84), we developed new HPLC gradients and observed that the peak coeluting with hPTH(1-84) could be separated into two entities recognized by a cyclase-activating PTH (CA-PTH) assay that reacts with the first four amino acids of the PTH structure. METHODS: Sera from six healthy individuals and five patients with primary hyperparathyroidism, and eight pools of sera from patients in renal failure were fractionated by HPLC. A total (T)-PTH assay reacting with the (15-20) region, the CA-PTH assay, and a COOH-terminal (C)-PTH assay with a (65-84) structure requirement were used to measure basal and fractionated PTH values. RESULTS: T-PTH was higher than CA-PTH in all healthy controls [mean (SD), 3.13 (0.37) vs 2.29 (0.33) pmol/L; P <0.01] and in renal failure patients [47 (35.1) vs 33.4 (26.1) pmol/L; P <0.01]. By contrast, CA-PTH concentrations were similar to or higher than T-PTH in three of five patients with primary hyperparathyroidism [25.7 (26.1) vs 23.1 (24.2) pmol/L; not significant]. The CA-PTH assay reacted with the hPTH(1-84) peak and with a minor peak different from the non-(1-84) peak recognized by the T-PTH assay. This minor peak was not recognized by the T-PTH assay. It represented 8 (2)% of CA-PTH in controls, 25 (23)% in patients with primary hyperparathyroidism, and 22 (7)% in renal failure patients, assuming equimolar reactivity to hPTH(1-84) in the CA-PTH assay. It was not oxidized hPTH(1-84), which migrated differently on HPLC and reacted similarly in the CA and T-PTH assays. CONCLUSIONS: This new molecular form of PTH has structural integrity of the (1-4) region but presumably is modified in the region (15-20), which is usually recognized by the T-PTH assay. Its clinical implications remain to be defined.

Chromatography, High Pressure Liquid↗
PubMed2002

Quinine pharmacokinetics in chronic haemodialysis patients.

AIMS: Quinine is often used to prevent muscle cramps in patients with chronic renal failure. A standard dose of 300 mg at bedtime is usually recommended, but little is known about the pharmacokinetics of quinine in the presence of renal failure. METHODS: We studied the pharmacokinetics of quinine in eight normal subjects and eight patients with chronic renal failure on haemodialysis after a single oral dose of quinine sulphate (300 mg). RESULTS: The concentration of alpha1-acid glycoprotein (AAG), the major binding protein for quinine, was increased in haemodialysis patients compared with control subjects (1.52 g l-1 vs 0.63 g l-1 [mean difference 1.033; 95% CI 0.735, 1.330]) whereas albumin levels were decreased (30 g l-1 vs 40 g l-1 [mean difference 9.5; 95% CI 3.048, 15.952]). Accordingly, the free fraction of quinine was decreased (0.024 vs 0.063 [mean difference 0.0380; 95% CI 0.0221, 0.0539]) and the apparent volume of distribution tended to decrease (0.95 l kg-1 vs 1.43 l kg-1 [mean difference 0.480; 95% CI 0.193, 1.154]). The quinine binding ratio correlated with the plasma concentration of AAG but not that of albumin. The clearance of free (unbound) quinine was increased in haemodialysis patients compared with controls (67.9 ml min-1 kg-1 vs 41.1 ml min-1 kg-1 [mean difference -26.8; 95% CI, -56.994, 3.469]), and the area under the curve (AUC) of the two main metabolites, 3-hydroxyquinine and 10,11-dihydroxydihydroquinine were increased. CONCLUSIONS: In patients with chronic renal failure, there is an increase in plasma protein binding and in the clearance of free drug, resulting in lower plasma concentration of free quinine.

Administration, Oral↗
PubMed1997

Plasma and saliva substance P levels: the effects of acute pain in pregnant and non-pregnant women.

Substance P like immunoreactivity (SPLI) and total protein (TP) concentrations in plasma and saliva were measured in 80 healthy female patients divided into the following four groups: women in group 1 were not pregnant and they were awaiting tubal ligation; women in group 2 were not pregnant but they experienced acute postoperative pain following hysterectomy; women in group 3 were pregnant and were awaiting elective cesarean section; and women in group 4 were in active labor and experienced acute labor pain. Pain intensity was assessed using verbal Likert pain scores. The absolute measured concentration of SPLI (SPLIabs) was divided by the TP concentration to obtain corrected SPLI (SPLIcorr) concentration. Results were expressed mean +/- 1 SE and analyzed using analysis of variance with 95% confidence (P < 0.05). SPLIcorr concentrations were 1.8 +/- 0.1, 1.8 +/- 0.2, 1.1 +/- 0.1 1.1 +/- 0.1 pg/mg protein in groups 1, 2, 3 and 4, respectively. Patients in both pregnant groups had significantly lower plasma SPLIcorr concentrations compared to the non-pregnant groups. However, the presence of acute postoperative pain or labor pain did not significantly alter plasma SPLIcorr concentrations. Saliva SPLI concentrations were not significantly different among the four groups.

Acute Disease↗