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Biomedical subjects

M Durand

Publications and source records attributed to M Durand.

At least 73 records · Page 4Linked to original sources
PubMed1998

Umbilical arteriovenous PO2 and PCO2 differences and neonatal morbidity in term infants with severe acidosis.

OBJECTIVE: In term infants umbilical cord gas analysis is a poor predictor of immediate newborn complications associated with intrapartum asphyxia, unless the umbilical arterial pH is less than 7.00. We investigated whether umbilical arteriovenous blood gas differences may better predict asphyxia-related complications. STUDY DESIGN: The study population consisted of 82 term, nonanomalous, singleton, live-born infants with severe umbilical acidosis (pH < 7.00). Umbilical arteriovenous pH, PCO2, and PO2 differences were correlated with Apgar scores and the presence of seizures, hypoxic-ischemic encephalopathy, cardiopulmonary and renal dysfunction, and abnormal development in the neonatal period. RESULTS: Umbilical arteriovenous pH, PCO2, and PO2 differences were interrelated (p < 0.0001), but these parameters correlated only weakly with 1-minute and 5-minute Apgar scores. An arteriovenous PCO2 difference > 25 torr was a highly sensitive and specific parameter in identifying asphyxiated infants with seizures, hypoxic-ischemic encephalopathy, cardiopulmonary and renal dysfunction, and abnormal development in the neonatal period. Arteriovenous PO2 differences were less sensitive in the detection of neonatal morbidity than arteriovenous PCO2 differences. CONCLUSION: Umbilical cord blood arteriovenous PCO2 differences provide a new tool to predict neonatal morbidity and permanent neurologic injury in term infants with perinatal asphyxia.

Acidosis↗
PubMed1998

Differential effects of neonatal handling on anxiety, corticosterone response to stress, and hippocampal glucocorticoid and serotonin (5-HT)2A receptors in Lewis rats.

Neonatal handling (during the first 3 weeks of age) has been reported by others to diminish the hypothalamo-pituitary-adrenal (HPA) responsivity to stress in adult Long Evans rats, an effect involving a serotonin (5-HT)2A receptor-mediated increase in glucocorticoid receptor (GR) gene expression in the frontal cortex and the hippocampus. In addition, handled animals may also display enduring reductions in anxiety-related behaviours, including in the elevated plus-maze. We have thus analysed the aforementioned neuroendocrine and behavioural consequences of neonatal stress in male and female adult Lewis rats, a strain characterised by its high anxiety and its hyporesponsive HPA axis. Plasma corticosterone, but not behavioural, responses to an elevated plus-maze test were decreased in handled rats. Besides, hippocampal mineralocorticoid receptor (MR) and GR binding capacities were not different between handled and non-handled Lewis rats, an observation which could be extended to our adult Long Evans rats. Lastly, neither hippocampal nor cortical 5-HT2A receptor binding capacities in adult Lewis rats were affected by prior handling. In keeping with the failure to detect early handling-induced increases in hippocampal GR binding in 3-week old Lewis and Long Evans rats, the present study reinforces past findings indicating that environmental and genetic factors are crucial variables in the neonatal handling paradigm.

Animals↗
PubMed1998

Obvious peritumoral emboli: an elusive prognostic factor reappraised. Multivariate analysis of 1320 node-negative breast cancers.

This study was conducted to determine the prognostic influence of obvious peritumoral vascular emboli as prospectively determined by a simple routine slide examination in patients with operable node-negative breast cancer. Obvious peritumoral emboli (OPE) were defined by the presence of neoplastic emboli within unequivocal vascular lumina (including both lymphatic spaces and blood capillaries) in areas adjacent to but outside the margins of the carcinoma. OPE were assessed routinely on 5 microns thick haematoxylin and eosin-stained sections for each of 1320 primary operable node-negative breast cancers from 1975 to 1992 at our institution. OPE and other prognostic variables (tumour size, SBR grade, oestrogen and progesterone receptor status) were correlated to overall survival (OS) and metastasis-free interval (MFI) by means of univariate and multivariate analysis with a median follow-up of 103 months. OPE were found in 19.5% of tumours. In univariate analysis, OPE were related to tumour size (P = 6.3 x 10(-5)) and histologic grade (P = 4.9 x 10(-7)). Statistically significant correlations were found with OS (P = 4.6 x 10(-5)) and MFI (P = 6.4 x 10(-9)). Furthermore, in multivariate analysis, OPE was an independent prognostic variable, the most predictive factor for MFI (P = 7.7 x 10(-7)) before tumour size and grade, and was second after tumour grade for OS (P = 0.002). This study on a large unicentric series and with a long follow-up confirms the prognostic significance of vascular emboli in patients with operable node-negative breast carcinoma. Importantly, vascular emboli were found to be accurately detectable by a simple routine and non-time-consuming method. Therefore, such obvious vascular emboli should be considered as an important cost-effective, prognostic variable in patients with node-negative breast carcinoma.

Adult↗
PubMed1998

Practical knowledge in expert coaches: on-site study of coaching in sailing.

The purpose of this study was to analyze the practical knowledge of expert sailing coaches of the French team preparing for the 1996 Olympic Games in Atlanta. Coaching knowledge was studied from a cognitive ergonomics perspective based on the task activity model. According to this model, a task is a set of constraints facing individuals. To meet the demands imposed by these constraints, an individual engages in an adaptative activity which can be studied from the point of view of his or her knowledge and cognitive operating modes. In-depth interviews were conducted after observation of five training sessions, and the verbal protocols obtained were coded inductively. The results showed that coaching tasks were considered by coaches as a set of interacting constraints which generate complex, contradictory, and ill defined problems. Coaches' operating modes appeared to be based on organization routines, cognitive anticipation on flexible plans, flexible on-site adaptation, joint control of training with athletes, and involvement in the training situation based on past experiences.

Adaptation, Physiological↗
PubMed1998

Spectroscopic investigation of an intramolecular DNA triplex containing both G.G:C and T.A:T triads and its complex with netropsin.

The triple helix formation by the oligonucleotide 5'd(G4T4G4-[T4]-G4A4G4-[T4]-C4T4C4) ([T4] represents a stretch of 4 thymine residues) has been investigated by UV absorption spectroscopy and circular dichroism. In a 10 mM sodium cacodylate, 0.2 mM disodium EDTA (pH 7) buffer, we show the following significant results: i) In the absence of MgCl2, the oligonucleotide adopts a hairpin duplex structure with the dangling tail 5'd(G4T4G4-[T4]). This 5' extremity, which contains separated runs of four guanine residues, does not assume the expected tetraplex conformation observed when this sequence is free. ii) In the presence of MgCl2, the oligonucleotide folds back on itself twice to give a triple helix via a double hairpin formation, with [T4] single-strand loops. iii) The addition of high concentration of KCl to the preformed triplex does not disrupt the structure. Nevertheless, if the oligonucleotide is allowed to fold back in the presence of K+, triplex formation is inhibited. Circular dichroism studies demonstrate that the oligonucleotide adopts a dimeric conformation, resulting from the association of two hairpin duplexes, via the formation of an antiparallel G-quadruplex by the telomeric 5'd(G4T4G4-[T4]) extremities. iv) Under the experimental conditions used in this report, the triplex melts in a monophasic manner. v) Netropsin, a DNA minor groove ligand, binds to the central site A4/T4 of the duplex and to that of the triplex in an equimolar stoichiometry. In contrast with previous studies concerning pyr.pur:pyr triplexes, thermal denaturation experiments demonstrate that the netropsin binding stabilizes the intramolecular triplex.

Base Composition↗
PubMed1998

Measles outbreaks in Micronesia, 1991 to 1994.

BACKGROUND: Several islands in Micronesia experienced large measles outbreaks, during 1991 through 1994. Except for Guam, none of the islands had reported measles outbreaks during the previous 20 years. METHODS: To characterize the outbreaks, measles surveillance data, hospital records and death certificates were reviewed. Preoutbreak vaccination coverage rates were assessed by reviewing public health vaccination records. Viral isolates were genetically sequenced to determine the source of transmission. Linear regression analysis was performed to assess the effectiveness of outbreak control measures. RESULTS: Between 1991 and 1994 more than 1300 measles cases and 16 measles-related deaths were reported in Micronesia. Preoutbreak vaccination coverage rates among 2-year-old children were 55 to 94%. Genetic sequencing of the viral isolates and epidemiologic investigations suggested transmission between islands and new importations from outside of Micronesia. The highest attack rates were among children ages < 5 years (20/1000) and 10 to 19 years (38/1000). Compared with attack rates among children ages < 1 and 10 to 19 years, attack rates were lower among those ages 5 to 9 years, in whom 2-dose vaccination coverage rates were highest (P < 0.001). Early and rapid implementation of mass vaccination campaigns was significantly associated with shorter duration of outbreaks (P = 0.049). CONCLUSION: The measles outbreaks in Micronesia show that island populations may be highly susceptible to measles. High two-dose vaccination coverage levels must be maintained to prevent such outbreaks. Early and rapidly implemented mass measles vaccination campaigns were effective in control of island outbreaks. Strengthening public health infrastructure and surveillance is necessary for early identification of outbreaks and rapid implementation of mass campaigns.

Adolescent↗
PubMed1998

Characterization of lymphocyte subpopulations in periapical lesions by flow cytometry.

The mechanisms by which the bacterial root-canal infection leads to periapical bone destruction (cysts or granulomas) are not yet well understood. Previous works have shown elements of an active immune response in the lesions. In the present study, flow cytometry was used to improve the characterization of immune cells. Semiquantitative immunohistochemical analysis showed the presence of plasma cells, macrophages and B and T cells. The simultaneous use of several antibodies in flow cytometry allowed a more precise phenotype of the lymphocytes. The cysts displayed an abundance of B lymphocytes at the same time as a relative scarcity of CD8+ cells. CD4+ lymphocytes were the dominant lymphocyte population in most cases. A small number of gamma delta T lymphocytes and natural killer cells was found. These preliminary results show that flow cytometry may be used to characterize immune cells from inflamed tissue and opens the possibility for further functional studies.

Adult↗
PubMed1997

The influence of sintering temperature on the proliferation of fibroblastic cells in contact with HA-bioceramics.

HA-ceramics used in human surgery as osteoconductive surfaces show a great variety of characteristics. Certain characteristics such as grain size, porosity, and surface area, are controlled by the sintering temperature of the slurry. We grew L-929 fibroblast cells on HA-ceramic disks that had been sintered at different temperatures ranging from 850 degrees-1350 degrees C. The cell line growth rate was lower on ceramic disks than on the culture-grade polystyrene used as a negative control. Cell growth correlated with the ceramic sintering temperature although no significant difference in the cell adhesion to the different ceramics was shown. Growth rate on ceramics sintered at low temperatures (850 degrees and 950 degrees C) was negative whereas it was positive on disks sintered at higher temperatures. When the cells were separated from the disks by a polycarbonate membrane, the growth rate was negative on those membranes in contact with low-temperature sintered disks and positive on the high-temperature sintered disks. The calcium and phosphorus concentration in the culture medium in contact with ceramics sintered below 1050 degrees C decreased during the culture period. Ceramics sintered between 1100 degrees and 1250 degrees C brought about an increase in Ca and P concentrations while ceramics sintered at higher temperatures did not induce any changes. SEM examination of the 850 degrees and 1200 degrees C sintered ceramics showed that the 850 degrees C sintered ceramics consisted of small grains with pores between them and the 1200 degrees C sintered ceramics were made of larger grains without any visible pores, thereby decreasing the surface of material in contact with the culture medium. This difference in surface area was confirmed by the fact that the amount of albumin absorbed onto the ceramic was dependent on the sintering temperature. In conclusion, the modification of the culture medium brought about by high-surfaced ceramics could influence the growth of cells with which such ceramics come in contact.

Animals↗
PubMed1997

Below-knee bypass using fresh arterial allografts for limb salvage: early results.

The purpose of this study was to evaluate early results of below-knee bypass using fresh arterial allografts as arterial substitutes for limb salvage. From April 1991 to September 1993, we performed 28 below-knee bypass procedures using fresh arterial allografts in patients without a suitable autologous vein. Allografts were obtained by multiorgan harvesting from brain-dead subjects and preserved at 4 degrees C. Histologic examination of grafts was carried out. Secondary patency at 2 years calculated using the Kaplan-Meier method was 64% (confidence interval [CI] 45%-79%). No signs of graft deterioration or rejection were noted. These preliminary results are encouraging but long-term assessment is needed before expanding the range of application.

Aged↗
PubMed1997

Effect of low-dose positive inotropic drugs on human internal mammary artery flow.

BACKGROUND: Dobutamine (a beta-receptor agonist), enoximone (a type III selective phosphodiesterase inhibitor), and epinephrine (an alpha- and beta-mimetic) frequently are used in the perioperative management of patients undergoing coronary artery bypass grafting. METHODS: We performed a double-blind clinical study to compare the effects on internal mammary artery free flow of low doses of these three positive inotropic drugs. Thirty patients in whom the left internal mammary artery was used for coronary artery bypass grafting were randomized into three groups. Internal mammary artery free flow and hemodynamic measurements were evaluated before and 10 minutes after the intravenous infusion of dobutamine (3 microg x kg(-1) x min(-1)), enoximone (200 microg/kg), or epinephrine (0.05 microg x kg(-1) x min(-1)). RESULTS: A significant increase in free flow occurred only in the dobutamine group (33 +/- 7.5 and 42.2 +/- 7.9 mL/min before and after drug infusion, respectively; p = 0.013). Comparison of the increase in flow between the groups, however, showed no difference. These drugs, at doses designed to produce a positive inotropic effect, caused little increase in the free flow of the internal mammary artery. CONCLUSIONS: The use of dobutamine, enoximone, and epinephrine as low-dose positive inotropic treatments in the perioperative and postoperative periods of coronary artery bypass grafting should depend on their positive inotropic effects rather than their vasodilative effects on the arterial grafts.

Adrenergic beta-Agonists↗
PubMed1997

Prone positioning decreases episodes of hypoxemia in extremely low birth weight infants (1000 grams or less) with chronic lung disease.

Extremely low birth weight infants with chronic lung disease (CLD) have frequent episodes of desaturation (hypoxemia). We quantified oxygenation and episodes of hypoxemia in 55 infants (birth weight < or = 1000 gm) with CLD in the supine versus prone position, for 1-hour time intervals. Oxygen saturation was measured with the Nellcor N-200 pulse oximeter and a computer program. Prone positioning increased oxygen saturation from 92.0% to 94.1% (p < 0.001) and significantly decreased episodes of hypoxemia to oxygen saturation levels of less than 90%, 85%, and 80% (p < 0.001). Our findings support prone positioning for the extremely low birth weight infant with CLD in an intensive care setting.

Chronic Disease↗
PubMed1997

Anxiety- and activity-related effects of diazepam and chlordiazepoxide in the rat light/dark and dark/light tests.

We have investigated, through factor analysis, anxiety- and activity-related variables in rats placed in the light/dark box. Thus, vehicle-, diazepam (DZ)-, and chlordiazepoxide (CDP)-treated rats were submitted 30 min later to 5-min light/dark or dark/light tests (initial placements in light or dark, respectively). Following this test, the animals were tested for 5 min in an automated activity monitor. Doses of DZ (0.75-3.0 mg/kg) and CDP (2.5-10.0 mg/kg) were based on preliminary evidence for 1.5 mg/kg of DZ and 5 mg/kg of CDP being anxiolytic in the elevated plus-maze. In the light/dark test, DZ increased the number of visits to and duration in the light compartment, and locomotor activity in the dark compartment; moreover, DZ decreased the latency to enter the light compartment. These effects were, however, significant for the highest dose only. Although CDP yielded similar behavioural effects, only the highest dose had a significant effect, namely, on latency to enter the light side. Conversely, none of the other variables were benzodiazepine-sensitive. Locomotion in the activity cages was decreased by DZ and CDP, an effect significant for the highest doses of benzodiazepines (dark/light test condition only). In both tests, factor analyses revealed an anxiety-related factor (to which all variables related to the visits in the light and part of the locomotion in the dark contributed), and an activity-related factor (upon which the latency to enter the dark and part of the locomotion in the dark loaded) in the light/dark test only. It is suggested that although the light/dark and dark/light tests capture an approach/avoidance dimension, DZ and CDP are more effective in the former test. Compared to the light/dark test, however, the plus-maze may be more sensitive to the anxiolytic effects of DZ and CDP.

Animals↗
PubMed1997

[Radiotherapy of spinal metastases in breast cancer. Apropos of a series of 108 patients].

PURPOSE: Retrospective analysis of analgesic, decompressive and remineralization effects of radiation therapy for spinal metastases in breast cancer. PATIENTS AND METHODS: From January 1990 to December 1992, 108 patients with breast cancer were treated by irradiation at the Bergonié Institute for a first spinal metastasis. Three patients had undergone previous surgery (laminectomy and Doves' frame). The indication of radiation therapy was analgesic (102 patients) or decompressive (six patients). The usual irradiation scheme was 30 Gy/10 fractions/2 weeks. RESULTS: The analgesic effect was considered as 'complete' or 'almost complete' (83%), 'moderate' (13%) or absent (4%). The mean time to the maximum analgesic response was 35 days. The duration of both the analgesic response and remineralization effects could not be retrospectively assessed due to lack of data. Decompressive effects were complete in five cases and absent in one case. A second spinal radiation therapy was necessary 78 times (eight times in junction field within 6 months following the first treatment). Spinal cord compression occurred either out of (three cases) or within (one case) the irradiated field. CONCLUSION: Radiation therapy for spinal metastases in breast cancer remains a palliative analgesic treatment. Indication for decompression is rare. However, assessment of compressive 'risk' leads to discussion of radiological staging (contribution of magnetic resonance imaging) and possible previous treatment (vertebroplasty or osteosynthesis).

Adult↗