PubMed Health⌕ Search

Biomedical subjects

J Seguin

Publications and source records attributed to J Seguin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Umbilical venous catheterizations: audit by the Study Group for Complications of Perinatal Care.

The Study Group for Complications of Perinatal Care, through 13 of its participating neonatal intensive care units, conducted a prospective audit to describe contemporary use of umbilical venous catheters (UVCs) over 3 months in 1951 admissions. Frequency of UVC attempts was 15.5% for all patients and greatest (50%) in patients of 1000 g or less birthweight (BW), with a wide range of frequency by institution and by BW grouping. Institutions with more 1500 g or less BW infants tended to use UVCs more frequently. The most common reason for placement was general intravascular access. A variety of fluids were infused, and in most cases heparin was employed. Mean duration of use was 4.4 days for all patients and longest (5.5 days) in infants in the 1001 to 1500 g BW group. The most common reason for UVC removal was lack of further need. UVCs appear to be used more commonly and for a longer duration than is currently recommended. There is a need for a prospective, randomized trial to assess the risks properly and maximize the benefits of UVC usage.

Canada↗
PubMed1994

Umbilical arterial catheter use: report of an audit conducted by the Study Group for Complications of Perinatal Care.

The Study Group for Complications of Perinatal Care through 13 of its participating neonatal intensive care units conducted an audit of umbilical artery catheter (UAC) use over 3 months. Of 1941 patient admissions, 582 (30%) had a UAC inserted and left in place for a mean of 4.9 days. The mean supplemental oxygen concentration (FIO2) at removal was 0.35 with over 55% of UACs remaining in place until FIO2 was less than 0.26. Institutional practices varied widely for positioning the catheter tip, use of heparin, and types of infusates, as did the frequency of adverse events that prompted removal of the UAC. Most institutions with multiple physicians found less consistency in practice patterns within their own units than presumed prior to the audit. Just two institutions preferred catheter placement in the abdominal aorta (low) with the others selecting a low site only after detecting a malposition below the initially sought thoracic level. All but one group routinely used heparin, although in varying concentrations and total doses. Patient weight and catheter duration were inversely correlated, with smaller patients having catheters left in place for significantly longer periods (P < 0.01). Similarly, smaller patients had a higher likelihood of catheter removal because of an adverse event; the adverse events were not necessarily related to longer duration. A significant relationship existed between positioning a catheter tip in the abdominal aorta and removal for adverse events (P < 0.05).

Catheterization, Peripheral↗
PubMed1993

Static morphometric bases for CT identification and evaluation of the outflow chamber of the left ventricle. Preliminary study in formalin-fixed heart.

A static morphometric study of the outflow chamber of the left ventricle (OCLV) was investigated in a series of 10 formalin-fixed hearts. A spatial reconstruction of the shape and the volume of the OCLV was carried out by means of a Somaton Plus TR4 Tomodensitometer (Siemens). The technic allows evaluation of the surface of the aortic and the mitral orifices and visualization of the three-dimensional OCLV and LV morphology, as well as calculation of their volumes. The limits of the technic in the dynamic study of the OCLV are presented.

Adult↗
PubMed1992

Biosynthesis of White Lupin Isoflavonoids from [U-C]l-Phenylalanine and Their Release into the Culture Medium.

Pulse-labeling experiments of white lupin (Lupinus albus L.) cell cultures with [U-(14)C]l-phenylalanine for 72 h resulted in the incorporation of the radioactivity into the isoflavone aglucones, glucosides, and prenylated derivatives. Both the aglucones genistein and 2'-hydroxygenistein and their 7-O-glucosides accounted for 85% of the total isoflavonoids identified in the cultured cells and contained 35% of the radioactivity, whereas the prenylated derivatives comprised 15 and 65%, respectively. Almost 20% of the labeled isoflavones of the cellular pool was recovered from the culture medium, 90% of which were monoprenylated and diprenylated derivatives containing 80% of the radioactivity. These results clearly demonstrate the release into the culture medium of a substantial amount of the endogenously synthesized isoflavonoids, especially the prenylated derivatives.

Journal Article↗
PubMed1992

Serotonin increases calcium current in human atrial myocytes via the newly described 5-hydroxytryptamine4 receptors.

In various species, including humans, 5-hydroxytryptamine (5-HT) has been shown to exert positive chronotropic and inotropic cardiac effects through different types of receptors. The goal of the present study was to investigate the regulation by 5-HT of voltage-gated Ca2+ channels in human atrial myocytes and to characterize the receptor involved. Cardiomyocytes isolated enzymatically and mechanically were voltage-clamped using the whole-cell configuration of the patch-clamp technique. Extracellular perfusion of 5-HT increased Ca2+ current (ICa) amplitude with a EC50 (0.1 microM) similar to that observed with isoprenaline. The effects of 5-HT were blocked by the addition of protein kinase A inhibitor in the pipette. In addition, the effects of 5-HT, isoprenaline, and intracellular cAMP on ICa were not additive. These results support the hypothesis that the inotropic effect of 5-HT in human atrial myocytes is related to an increase of ICa via an elevation of intracellular cAMP levels and stimulation of cAMP-dependent protein kinase. The effects of 5-HT were not blocked by antagonists of 5-HT1 (methiothepin), 5-HT2 (ketanserin), or 5-HT3 (ICS 205-930 at a low concentration) receptors. The benzamide derivatives renzapride and zacopride and the azabicyclobenzimidazolone derivative BIMU 8 increased ICa, but less efficiently than did 5-HT or 5-methoxytryptamine. Moreover, ICS 205-930 at high concentrations (greater than 1 microM) completely antagonized the effects of 5-HT. Thus, the pharmacology of the 5-HT receptor involved in an increase of ICa in human atrial myocytes resembles that recently described for the 5-HT4 receptor. In atrial myocytes dissociated from rat, rabbit, guinea pig, or frog, 5-HT at high concentrations had no effect on Ca2+ currents, suggesting that the distribution of 5-HT4 receptors in cardiac tissues is species dependent.

Animals↗
PubMed1992

Effects of transcutaneous monitor electrode heat on skin servo-controlled environments.

This study tested the hypotheses that (1) the heat generated by a transcutaneous monitor electrode is sufficient to decrease skin servo-controlled radiant warmer heat output when it is positioned next to the operating skin servo-thermistor, and (2) the decrease in radiant warmer heat output is enough to lower body temperatures or cause a heat-conserving response in a baby. Seventeen newborns less than or equal to 5 days old, gestational age 29 to 40 weeks, cared for under radiant warmers were studied before and for 30 minutes after juxtaposition of the transcutaneous monitor electrode and the skin servo-controlled thermistor. Mean radiant warmer heat output, measured as watt-hours/5 minute periods, decreased for the first 15 minutes after movement, mainly in the infants cared for under an older model radiant warmer. Mean skin temperature and foot temperature decreased, and esophageal-foot temperature gradient increased for those under the older model radiant warmer. Despite differences in the gestational age of the infants under the older compared with the newer model radiant warmer, multiple regression analysis indicated a significant effect of the model of radiant warmer on the results. Many factors can influence the proper functioning of servo-controlled heating systems, including the type of electronic logic and extraneous sources of heat. These factors require more study, and should be considered in the evaluation of thermal control problems.

Body Temperature↗
PubMed1990

Constitutive production of interleukin-6 and immunologic features in cardiac myxomas.

The constitutive production of interleukin-6 (IL-6), a potent hepatocyte-stimulating factor and B cell-differentiating factor, was demonstrated in 3 patients with cardiac myxomas. Tumor cells from the only patient who presented with immunologic features produced 14-23-fold higher levels of IL-6 than those from the 2 patients who lacked such features. A significant serum IL-6 level (56 pg/ml), greater than that observed in patients with active rheumatoid arthritis, was also observed only in this patient, with a subsequent return to an undetectable level after surgical removal of the tumor. This was associated with a regression of the immunologic features. This same patient was observed to have an IL-6-dependent, proliferative polyclonal plasmacytosis of the bone marrow. These observations demonstrate that an overproduction of IL-6 by cardiac myxoma cells, in association with a systemic passage of this IL-6, may be responsible for the immunologic features similar to those observed in true autoimmune diseases such as rheumatoid arthritis.

Acute-Phase Proteins↗
PubMed1989

Electrophysiological effects of penticainide (CM 7857) in isolated human atrial and ventricular fibers.

The intracellular electrophysiological properties of a new antiarrhythmic agent, penticainide (5 x 10(-6) to 5 x 10(-5) M) were studied in isolated driven human right atrial appendage and papillary muscle superfused with oxygenated Tyrode's solution. In atrial fibers, penticainide decreased the amplitude, maximum rate of rise (dV/dtmax), plateau amplitude, and duration (APD) of action potentials (AP). In ventricular fibers, the main AP modification induced by penticainide was a dV/dtmax diminution. All those effects were frequency and concentration dependent. Penticainide decreased resting potential at 5 x 10(-5) M only. Ventricular APD variations were relatively weak: in most of the cases, 5 x 10(-6) M decreased APD and 5 x 10(-5) M shortened long APD (greater than 300 ms) and lengthened short APD (less than 300 ms). The class I antiarrhythmic property (dV/dtmax decrease) of penticainide was rate dependent in both human fibers and was obtained at lower drug concentrations than those used in other species. The relatively rapid rate of onset and the rather slow recovery kinetics of dV/dtmax block suggest a common mechanism of action of penticainide on sodium channels in human heart and others mammals.

Action Potentials↗
PubMed1988

Intramyocardial distribution of hydroquinidine in the dog.

Hydroquinidine concentrations were measured simultaneously in the plasma and in right atrial and ventricular biopsy samples of four dogs in the steady state after eight days of oral sustained release hydroquinidine administration. The right ventricular concentrations were greater than the plasma concentrations in all samples (ratio 5.02(2.2)). In necropsy samples the ventricular concentrations were higher than the atrial concentrations, (ratio 1.54(0.36); p less than 0.01) and than the concentration in the sinus node region (7.72(1.85) ng.g-1 vs 4.21(2.6) ng.g-1). This study shows that intramyocardial pharmacokinetic measurements are possible and may help towards a better understanding of antiarrhythmic agents, particularly those with cumulative myocardial effect.

Animals↗
PubMed1988

[Surgery of coronary revascularization in patients over 70. Apropos of 40 cases].

40 of the 900 patients operated upon for aorto-coronary bypass grafting between January 1980 and October 1984, were over 70 years old (mean 71.1; range: 70-76 years old). 25 had severe angina pectoris (class III or IV) and 15 of them had emergency surgery. An average of 2 grafts per patient was performed with 3 deaths and 3 myocardial infarcts in the peri-operative period. Patients had an average of 21 months follow-up (range 5 years, 3 months); in that period 2 deaths due to myocardial infarction, 3 persistent angina pectoris (class II) and 32 asymptomatic patients were observed. These results illustrate advances in cardiac surgery, anesthesia and postoperative management. Coronary surgery may therefore be performed in patients over 70 years old with an acceptable operative risk and satisfactory longterm results.

Aged↗
PubMed1987

Differential recognition of oral indigenous bacteria by salivary immunoglobulins A and G.

Assuming that salivary immunity to indigenous microorganisms could develop, we assessed antibacterial reactivities of natural salivary antibodies in specific pathogen-free inbred mice. An ELISA was set up, using whole bacterial cells, to map reactivities of salivary IgA and IgG which accounted respectively for 91% and 8.7% of salivary Ig's in the BALB/c mouse. Representative strains of seven species from three genera (Lactobacilli, Staphylococci, and Streptococci), including major and minor components of the murine oral flora (38, 43, and 8%, respectively), were used to determine the presence and level of specific antibodies in individual saliva. It was verified that naturally occurring IgA antibodies can display diverse antibacterial reactivities. A characteristic profile emerged for salivary IgA where antibodies to Streptococcus faecalis predominate. Natural salivary IgG antibodies did not show the same reactivity pattern as IgA, anti-Lactobacilli and anti-Staphylococci reactivities being much less frequent in the salivary IgG repertoire. However, antibodies to S. faecalis occurred at the same high frequency for both isotypes (62-70% of the samples). Besides being species-specific, antibacterial reactivities were also found to be strain-specific. Broad variations in antibacterial titers were detected among individual mice under standardized experimental conditions. Present data thus suggest that the dynamics of salivary antibody production in the mouse reflect a differential natural sensitization of the secretory (IgA) versus the systemic (IgG) immune systems by distinct populations of indigenous bacteria.

Animals↗