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Biomedical subjects

J St Pierre

Publications and source records attributed to J St Pierre.

15 recordsLinked to original sources
PubMed2003

Prolonged procoagulant activity on overstretch-injured coronary arteries in pigs.

This study was designed to assess the time course and nature of the vascular procoagulant response after 1.5-fold balloon overstretch injury of the coronary arteries in pigs. Arteries were excised for chromogenic assay of bound factor (F)Xa and thrombin at 24 h, 3 days, 1 week, or 2 weeks after injury. FXa at the site of injury remained elevated for 1 week (4.9 +/- 5.9 microg cm(-2), n = 10), compared with non-injured control arteries (0.4 +/- 0.2 microg cm(-2), n = 18, P = 0.00025), while thrombin was increased only at 24 h. Tissue factor protein was abundant in non-injured coronaries (10 +/- 6 ng microg(-1) total protein, n = 9) and levels were unchanged by injury (13 +/- 11 ng microg(-1), n = 6) or 24-h administration of tissue factor pathway inhibitor (16 +/- 6 ng microg(-1), n = 6). Persistent tissue factor-mediated procoagulant activity may explain the need for prolonged anticoagulation to attenuate neointimal formation after balloon-induced coronary injury.

Angioplasty, Balloon, Coronary↗
PubMed1999

Seasonal cycles of mitochondrial ADP sensitivity and oxidative capacities in trout oxidative muscle.

Mitochondria from red myotomal muscle of rainbow trout, Oncorhynchus mykiss, showed seasonal cycles of their maximal rates of substrate oxidation (nmol.min-1 mg-1 mitochondrial protein) and their apparent ADP affinity (Kmapp), as well as in the thermal sensitivity of these properties. Increases in the maximal capacity of pyruvate oxidation were sufficient to compensate for seasonal changes in temperature, except during the winter months when rates at habitat temperature were depressed relative to other periods. The ADP affinity of isolated mitochondria was highest during cold months. Thus, the Kmapp for ADP at habitat temperature showed less seasonal variation than the ADP Kmapp at a given temperature. A loss in ADP affinity with decreasing temperature occurred through much of the year, and only was definitively suppressed in December and July. Both the ADP affinity and the maximal oxidative capacities of muscle mitochondria seem to be regulated parameters.

Acclimatization↗
PubMed1999

Comparison of methods for local delivery of tissue factor pathway inhibitor to balloon-injured arteries in rabbits.

BACKGROUND: Prolonged intravenous infusions of recombinant tissue factor pathway inhibitor (rTFPI) have been shown to attenuate markedly neointimal formation and stenosis after balloon-induced injury to the carotid arteries in minipigs. DESIGN: Because local delivery of rTFPI to the injury site would be clinically advantageous, we designed this study to compare the local delivery and retention of rTFPI in balloon-injured arteries using three catheter-based systems. METHODS: Similar amounts (range 3-4.5 mg) of a mixture of 125I-labeled and unlabeled rTFPI were delivered by either passive diffusion at moderate pressure (5 x 10(5) Pa with the LocalMed InfusaSleeve, or 4 x 10(5) Pa with the SciMed Dispatch device), or facilitated diffusion combining lower pressure (2 x 10(5) Pa) and electrical current (3.5 mA/cm2; e-MED, iontophoresis) to balloon-injured carotid arteries in anesthetized rabbits. RESULTS: Comparable amounts of rTFPI were retained on the injured vessels immediately after delivery (t = 0) with the LocalMed (628 +/- 68 micrograms/g per cm2, n = 4), SciMed (522 +/- 167 micrograms/g per cm2, n = 4), and e-MED (497 +/- 142 micrograms/g per cm2, n = 4) catheters (NS). However, rTFPI was decreased by 37% after 24 h compared with t = 0 (P < 0.02) in the e-MED group, but was increased 1.5-fold (P = 0.02) and 1.3-fold in the SciMed and LocalMed groups, respectively, presumably because of redistribution of rTFPI from remote endothelial or perivascular sites. Retention of rTFPI was six to nine times higher for injured compared with non-injured arteries, and persisted for at least 48 h after delivery with the LocalMed catheter. CONCLUSIONS: Sustained, marked retention of rTFPI delivered locally at the site of balloon-induced arterial injury appears to result from catheter-based systems that use passive diffusion at moderate pressure.

Angioplasty, Balloon↗
PubMed1999

Tissue factor pathway inhibitor attenuates procoagulant activity and upregulation of tissue factor at the site of balloon-induced arterial injury in pigs.

Intravenous infusion of recombinant tissue factor pathway inhibitor (rTFPI) for 24 hours decreases neointimal thickening and luminal stenosis 1 month after balloon-induced injury to the carotid arteries in minipigs. This study was designed to determine whether the effect of rTFPI is accounted for by early decreases in procoagulant activity and thrombosis on the injured vessel wall. Vascular injury was induced by balloon hyperinflations in both carotid arteries of anesthetized pigs given no anticoagulant as a control (n=16), an intravenous infusion for 24 hours of rTFPI (0.5 mg/kg bolus and 25 microg. kg(-1). min(-1), n=14), or an intravenous infusion of unfractionated heparin (100 U. kg(-1). h(-1), n=19). Accumulation of radiolabeled autologous platelets was markedly decreased over 24 hours on injured arteries from animals given rTFPI (0.6x10(6)/cm(2)) compared with controls (2.5x10(6)/cm(2), P=0.0004). Deposition of radiolabeled fibrin was also decreased in rTFPI-treated animals (269+/-266 microg/cm(2)) compared with controls (2389+/-1673 microg/cm(2), P=0.04). Similar effects were observed with heparin. However, factor Xa activity, assayed after 24 hours by incubation of the injured arterial segments with the chromogenic substrate S-2222, was decreased more markedly on arteries from rTFPI-treated animals (0.14+/-0.13 OD) than those from heparin-treated animals (0.29+/-0.18 OD) compared with controls (0. 47+/-0.24 OD, P=0.0007). In addition, arteries from rTFPI-treated animals showed a 4-fold lower induction of tissue factor protein compared with controls (P=0.0002). Attenuation of procoagulant activity and tissue factor-mediated thrombin generation in response to injury may account for the promising results with rTFPI in the porcine angioplasty model.

Animals↗
PubMed1998

Functional decline in hospitalized elders: preventive nursing measures.

Functional status in older adults admitted to hospitals is a major predictor of outcomes. Functional decline, which is complex and multifactorial in cause, is a common complication of hospital stays. Many factors contributing to functional decline are preventable and treatable by proper nursing. Advanced practice nurses have an important, multifaceted role to play in resolving this geriatric problem.

Activities of Daily Living↗
PubMed1996

Cord lactate, pH, and blood gases from healthy neonates.

Lactate, pH, pO2, and pCO2 were determined in arterial, venous, and free-flowing mixed umbilical cord blood obtained from deliveries of apparently healthy neonates. The goals of this study were to establish reference ranges for lactate and pH against which results in cases of high-risk labor and delivery could be compared, to see how the gases correlated with these values, and to determine whether easily accessible mixed umbilical cord blood can serve as the sample in lieu of cord arterial or cord venous blood. Arterial and venous cord lactates were 2.98 mmol/l (+/- 1.40) and 2.80 mmol/l (+/- 1.35), respectively, from 85 cords obtained from vaginal and cesarean deliveries. Mixed cord blood lactate, obtained on 48 cords, was 2.72 mmol/l (+/- 1.28) versus 3.14 and 2.97 mmol/l for the arterial and venous samples from those cords, respectively, and correlated quite well with lactate from the venous specimens (r = 0.97). Differences of > 0.5 mmol/l occurred between mixed and arterial cord bloods in 21 patients, and between mixed and venous cord bloods in 6 of the 48 patients, respectively. We conclude that (1) less than 2.5% of deliveries of apparently healthy neonates have arterial, venous, or mixed cord lactates > or = 7.0 mmol/l and pH < or = 7.15, (2) neither cord venous pO2 nor pCO2 correlate well with cord venous lactate, and (3) readily available mixed cord blood is a satisfactory specimen for the measurement of venous cord latate.

Carbon Dioxide↗
PubMed1996

Delirium in hospitalized elderly patients: off track.

Delirium in the hospitalized elderly patient is highly prevalent and has severe consequences. Critically ill elderly individuals are at particular risk for delirium because of impaired physical and mental defense mechanisms. More research in terms of etiology, detection, treatment, and especially prevention, needs to be done. Although nursing care and nursing research have contributed much to our current knowledge of this complex condition, more will be contributed toward its understanding and management during the next decade. It is imperative that nurses attempt to keep abreast of this progress to provide the quality and cost-effective care that can keep older patients "on track."

Age Factors↗
PubMed1988

Performance of a solid phase enzyme immunoassay for detection of group A streptococci in a pediatric office laboratory as refereed by a hospital laboratory.

We evaluated the performance of a new rapid solid phase enzyme immunoassay, SUDS Group A Strep (MUREX Corp., Norcross, GA) for the detection of Group A beta-hemolytic streptococci in a pediatric office practice. Duplicate throat swabs were obtained from 341 children with pharyngitis. One swab was used in the SUDS test and the other was cultured in the office laboratory. Office SUDS and culture (sheep blood agar plate, aerobic 24-hour incubation) were compared with culture using reference techniques (sheep blood agar plate, anaerobic 48-hour incubation) in a hospital laboratory. Compared with hospital laboratory culture, the sensitivity of office SUDS (73.8%) was superior to that of office culture (66.6%) at P = 0.05. Specificities were 93.1 and 98.6%, respectively; positive predictive values were 86.1 and 96.6%; and negative predictive values were 85.9 and 83.5%. The sensitivity and specificity of SUDS compared with office culture were 88.5 and 87.8%, respectively, but would have been 93 and 94% had hemolyzed media not been used on several occasions in the office culture procedure. We conclude that SUDS Group A Strep was significantly more sensitive than throat cultures as performed in a typical pediatric practice although the performance of office cultures could have been improved by standard quality control techniques.

Bacteriological Techniques↗
PubMed1976

Statistical tables to detect significance between frequencies in two small samples, with particular reference to biological assays.

By simply referring to one of three tables, derived from Fisher's exact factorial method and obtained with the aid of a computer, it is possible to decide readily if differences observed between two small and equal or unequal size series are statistically significant at probability levels of 0.10, 0.05 and 0.01. The same can be very helpful for planning experiments. Examples are given in various fields of biology.

Computers↗
PubMed1971

BCG vaccination and pulmonary tuberculosis in Quebec.

The BCG vaccination program officially set up in 1949 in the Province of Quebec has been retrospectively evaluated for the period from 1956 to 1961. Two series of age groups were studied, 0-14 and 15-29, each comprising populations of several hundred thousand. At the beginning and the end of the period, the rates of primary vaccination were, in percentages of viable births, from 40 to 47.8 and, in cumulative percentages, for the 0 to 14 year age group, from 39.98 to 53.41, and for the 0 to 29 year age group, from 29.22 to 45.98.During this period, the ratios between the yearly rates of incidence of new cases of pulmonary tuberculosis per 100,000 in vaccinated and non-vaccinated individuals ranged from 1-2.5 to 1-3.5 within the age group 0-14 years and from 1-4.5 to 1-7 within the age group 15-29 years. When only the incidence of the more severe forms of tuberculosis is considered, the ratios ranged from 1-3.7 to 1-6.0 for the younger group and from 1-5.3 to 1-7.6 for the older one.Mortality from pulmonary tuberculosis was practically non-existent in the vaccinated groups and decreased from 2.5 to 1.3 per 100,000 population in the non-vaccinated groups.

Adolescent↗