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Biomedical subjects

M Durand

Publications and source records attributed to M Durand.

At least 163 records · Page 9Linked to original sources
PubMed1989

Cardiopulmonary and intracranial pressure changes related to endotracheal suctioning in preterm infants.

Although endotracheal (ET) suctioning is performed frequently in sick newborn infants, its effects on cardiorespiratory variables and intracranial pressure (ICP) have not been thoroughly documented in neonates greater than 24 h who were not paralyzed while receiving mechanical ventilation. This study evaluates these changes in preterm infants who required ventilatory assistance. We measured transcutaneous PO2 and PCO2 (PtcO2 and PtcCO2, respectively), intra-arterial BP, heart rate, ICP, and cerebral perfusion pressure (CPP) before, during, and for at least 5 min after ET suctioning in 15 low birth weight infants less than 1500 g and less than or equal to 30 days of age. One infant was studied twice. A suction adaptor was used to avoid disconnecting the patient from the ventilator and to attempt to minimize hypoxemia and hypercapnia during suctioning. The patients were studied in the supine position and muscle relaxants were not used. PtcO2 decreased 12.1% while PtcCO2 increased 4.7% 1 min after suctioning; however, greater increases in mean BP (33%) and ICP (117%) were observed during suctioning. CPP also increased during the procedure. ICP returned to baseline almost immediately, whereas BP remained slightly elevated 1 min after suctioning. Our findings demonstrate that ET suctioning significantly increases BP, ICP, and CPP in preterm infants on assisted ventilation in the first month of life. These changes appear to be independent of changes observed in oxygenation and ventilation.

Blood Pressure↗
PubMed1989

Evaluation of lung mechanics in rabbits using short duration flow pulses.

An alternative method of evaluating pulmonary mechanical function that uses short duration flow pulses was applied in five adult rabbits with high frequency flow interruption (HFFI) at 4 cycles per second. Variations in the total pressure across the respiratory system were partitioned into separate lungs and chest wall components, and the mechanical impedance of each component was evaluated in the range of 4 to 40 Hz using cross and power spectral analysis and spectral averaging. The resistances, R, of the respiratory system, lungs, and chest wall were 23.5 (2.3 SD), 18.6 (2.8), and 4.9 (1.5) cm H2O.L-1.s, respectively. These values were similar to R obtained by the conventional method at ordinary rates of ventilation, with the exception of chest wall resistance, which was approximately 50% smaller than R obtained by the conventional method. The compliances of the respiratory system, lungs and chest wall were 1.40 (0.19), 2.88 (0.94), and 2.85 (0.86) ml.cm H2O-1, respectively. In all cases, compliance values obtained by pulse analysis were roughly 70% of the values obtained by the conventional method. The smaller compliance values obtained with the pulse method may reflect the multicompartment behavior of the lungs and chest wall at the high frequencies found in the pulse spectra. We conclude that the response of the respiratory system to short duration flow pulses may be used to evaluate pulmonary mechanical function. The brief duration of the flow pulse suggests that this method may be well suited to evaluate lung function in uncooperative subjects, particularly newborns and premature infants.

Airway Resistance↗
PubMed1989

[Cancers of the breast at metastatic high-risk: prediction of survival by steroidal receptors].

From 1982 to 1985, 279 patients with locally advanced breast cancer have been treated with induction chemotherapy, adjusted loco-regional treatment (surgery and/or radiotherapy) and adjuvant chemotherapy with or without immunostimulation. Overall and relapse free survivals are better for tumors with estrogen and progesterone receptors (EPR). For these patients, we may hope that tumoral reduction with hormonotherapy would get the same overall and relapse-free survivals as induction chemotherapy.

Breast Neoplasms↗
PubMed1989

[Persistence of serologic and allergic reactions in ewes after vaccination with the H.38 or Rev.1 vaccines in a brucellosis (Brucella melitensis) enzootic area].

In a flock of 2,000 ewes located in an endemic area of Brucella melitensis infection, subjected to systematic vaccination of lambs either with killed and adjuvanted B. melitensis H.38 vaccine from 1973 to 1978, or with living B. melitensis Rev.1 vaccine since 1979, reactions to allergic intrapalpebral test, complement fixation test and Rose Bengal plate test were recorded in small groups of animals vaccinated four, three, two or one years ago. Four years after H.38 vaccination, 39 ewes out of 40 (97%) remained positive at least to one of the three tests. After vaccination with strain Rev.1, 16% out of 153 ewes vaccinated one to four years before were positive. These results were discussed according to two aspects: 1) infectious or vaccinal origins of these positive reactions; 2) consequences on implement of test and slaughter procedures in a vaccinated flock: allergic or complement fixation tests would have led to eliminate 9% out of ewes vaccinated with the Rev.1 vaccine, but only 1% with the Rose Bengal plate test.

Animals↗
PubMed1988

Subsequent development of acute non-lymphocytic leukemia in patients treated for Hodgkin's disease.

A nested case control study was carried out to investigate the association between treatment of patients with Hodgkin's disease (HD) and the risk of developing acute non-lymphocytic leukemia (ANLL). Seven Cancer Centers of the International Cancer Patient Data Exchange System of the UICC participated. A study cohort was selected consisting of 1,681 nonpretreated patients with HD, diagnosed from 1972 through 1978, and followed up through 1984. The median follow-up time was 66 months. Eighteen cases of leukemia were observed in the cohort. The risk of development of ANLL was significantly greater for male than for female patients. The treatment characteristics associated with an increased risk of developing ANLL were extensive radiotherapy, splenectomy and the chemotherapy combination of vincristine, procarbazine and mechlorethamine.

Acute Disease↗
PubMed1988

Circular dichroism studies of an oligo-alpha-thymidylate and of its interactions with complementary sequences.

An octathymidylate synthesized with the alpha anomer of thymidine has been studied using circular dichroism. Its conformation has been compared to that of its analogue containing the naturally occurring beta anomer. In both compounds some degree of intramolecular stacking is present as indicated by the shapes of the circular dichroism spectra and their variations with temperature. As its beta-analogue the alpha-octathymidylate binds to its complementary sequences containing beta-nucleosides. Only complexes with 1A:1T stoechiometry were observed. Binding to ribose- containing oligomers and polymers is much stronger than binding to deoxyribose-containing analogues. Circular dichroism spectra provided evidence for a difference between the geometry of the various complexes formed with an alpha-oligothymidylate and those formed with its beta-anomer-containing analogue.

Adenine Nucleotides↗
PubMed1988

Adjuvant trial for stage II receptor-positive breast cancer: CMF vs. CMF + tamoxifen in a single centre.

The purpose of a randomized trial achieved in a single centre (Fondation Bergonié, Bordeaux, France) was to compare chemotherapy alone (intravenous CMF) versus chemotherapy and hormonotherapy (CMF plus tamoxifen-30 mg per day during 2 years), for patients with stage II breast carcinoma and positive values of estrogen and/or progesterone receptor (EPR) (greater than 10 and greater than 15 fmoles mg protein-1 respectively). Three hundred and thirty four women treated by surgery +/- radiotherapy are included in this trial from 06.01.81 to 12.31.84. No patient is lost for follow-up. Eight are excluded. Three hundred and twenty six patients are evaluable with a 38 month median follow-up. For EPR assay, the dextran charcoal micromethod was used in the same centre. The two groups are identical as far as age, hormonal status, TNM, EPR values, and histological features are concerned. Analysis of results shows a significant improvement of relapse free survival (p = 0.018) and also overall survival (p = 0.04) for the CMF+ tamoxifen group.

Adult↗
PubMed1988

Production of volatile fatty acids as a result of bacterial interactions in the cecum of gnotobiotic rats and chickens fed a lactose-containing diet.

Volatile fatty acid (VFA) productions from lactose and lactate by a Clostridium butyricum and a Veillonella alcalescens strain, alone or in combination with a Lactobacillus acidophilus strain, were determined both in vitro in culture media and in vivo in the ceca of gnotobiotic animals. Gnotobiotic rats, which possess intestinal lactase, and chickens, which are devoid of it, were used. Both animal species were fed a diet containing 4% lactose. The in vitro results showed that the C. butyricum strain fermented lactose and D-lactic acid to butyric and acetic acids, whereas L-lactic acid was not fermented. The V. alcalescens strain did not ferment lactose and fermented L better than D-lactic acid. The in vivo results showed that high VFA concentrations were obtained in the ceca of chickens either disassociated with V. alcalescens or C. butyricum and Lactobacillus strains or monoassociated with C. butyricum. VFA concentrations in the ceca of rats were low, whatever strain the rats harbored. In addition, an antagonistic effect of the C. butyricum strain against the Lactobacillus strain was evidenced both in rats and chickens. It is suggested that the absence of a host lactase makes the chick a good model for lactose intolerance studies in human newborns.

Anaerobiosis↗
PubMed1988

Influence of major minerals on rumen microbiota.

The supply of minerals needed to meet rumen microbe requirements should match the amount of energy available for fermentation. Therefore, we attempt to assess microbial requirements for phosphorus (P), sulfur (S) and magnesium (Mg) in terms of fermentable organic matter at the rumen level (OMF) or in terms of digestible matter in the total tract (OMD). In vivo, about 5 g of P and 1.8 g of S/kg OMD should be available (a) in the rumen. Pa is provided mostly by salivary secretion, which depends on several dietary factors as well as on the physiological state of the animal; dietary S supply with natural diets depends on dietary S availability, which can be particularly low for some roughages. Dietary Mg concentration should be in the range 1.5-2.5 g/kg OMD. The circumstances in which major minerals may be used to manipulate rumen fermentation are discussed. With a high concentrate diet the addition of a mineral buffer may help to maintain an adequate pH for cellulolysis and enhance the efficiency and quantity of the microbes produced. Some inconsistent results are obtained, possibly because of the sensitivity of rumen microbes to high osmolality. It is concluded that, as the margin between optimal stimulatory concentration and toxic excess is narrow, rumen fermentation should be manipulated cautiously when using minerals.

Animals↗
PubMed1988

Arm fat and muscle areas in infancy.

Growth of arm muscle, fat and water areas were evaluated longitudinally in a prospective study in 81 infants from birth to the age of 12 months. The percentage of arm fat area v the cross sectional upper arm area increased at the age of 15 days with a peak peak at the age of 6 months while arm muscle area increased progressively throughout the year. As arm water area represented only 1% of cross sectional upper arm area, calculations of arm fat and muscle areas can be carried out from measurements of mid arm circumference and tricipital skinfold at 15 seconds. Percentiles are presented for the upper arm fat and muscle areas, which can be used as index for the infants' nutritional state.

Adipose Tissue↗
PubMed1988

Gas exchange during high frequency flow-interruption in rabbits before and after bronchoalveolar lavage.

The performance of a high frequency flow-interrupter (HFFI) type neonatal ventilator was evaluated on nine adult rabbits (control) and on five adult rabbits after bronchoalveolar lavage (BAL). Tidal volumes and airway pressures were measured during conventional ventilation and during HFFI at rates of 4, 6, 8, 10, and 12 cycles/s. Tidal volumes were adjusted to maintain PaCO2 between 35 and 42 mm Hg in control rabbits and 35-55 mm Hg in BAL rabbits; a positive end-expiratory pressure of 4 cm H2O was applied to BAL rabbits to reduce atelectasis and improve gas exchange. The normalized tidal volume required to maintain PaCO2 within the specified range during HFFI varied between 2.02 ml/kg (0.30 SD) and 2.55 (0.41) in control rabbits and between 2.65 (0.57) and 2.97 (0.51) in BAL rabbits. In neither group did the normalized tidal volume vary systematically with the rate of ventilation (p less than 0.05). Mean airway pressures were lower during HFFI than during conventional ventilation in control rabbits but comparable in the BAL group. Peak inflation pressures were greater during HFFI than conventional ventilation in control rabbits but similar in the BAL group. End-expiratory lung volume was not affected by ventilation rate during HFFI in control rabbits. We conclude 1) that HFFI can maintain gas exchange in rabbits suffering from acute respiratory distress with airway pressures that are comparable to those measured during conventional ventilation and 2) the capacity of HFFI to ventilate the lungs with significantly lower airway pressures than conventional ventilation depends, in part, on the condition of the lungs.

Animals↗
PubMed1987

Effects of metaproterenol on pulmonary mechanics, oxygenation, and ventilation in infants with chronic lung disease.

Changes in pulmonary resistance, dynamic compliance, tidal volume, and transcutaneous PO2 and PCO2 after nebulized administration of metaproterenol were evaluated in eight newborn infants (birth weight 650 to 1060 g, gestational age 25 to 28 weeks) with chronic lung disease receiving mechanical ventilation. The infants were monitored continuously before and for 15 minutes after nebulization of metaproterenol during 3 consecutive days at mean age 34 days. There were significant increases in compliance, tidal volume, and tcPO2, and significant decreases in pulmonary resistance and tcPCO2. These data show that bronchospasm contributes significantly to the high pulmonary resistance in preterm infants with chronic lung disease and that metaproterenol is beneficial in the therapy of infants with chronic lung disease requiring mechanical ventilation.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Effects of phosphorus deficiency on rumen microbial activity associated with the solid and liquid phases of a fermentor (Rusitec).

The rumen simulation technique (Rusitec) has been used to study the effects of phosphorus (P) deficiency on bacterial protein synthesis and chemical composition and on adenosine triphosphate (ATP) concentrations in the solid and liquid phases of fermentors. 16 g DM of a P-deficient mixed diet was put into each vessel daily and the vessels were infused with about 1 l of a P-deficient (0 mg of P) or P-supplemented (120 mg of P/l) buffer. Two vessels per treatment were used, and during a second experimental period the deficient and supplemented buffers were interchanged to determine the effects of P repletion and depletion. The proportion of bacterial N directly incorporated from dietary amino acids or peptides was greater in solid-associated bacteria (SAB) than in liquid-associated bacteria (LAB) (46 vs 19%). P deficiency increased this proportion in both bacterial populations. Protein synthesis associated with the solid phase represented about 30% of the total protein synthesis in the system. P deficiency induced a marked decrease in microbial protein synthesis in both phases. Microbial yield declined by about 5 points (g of N/kg OMF) in P-deficient conditions. ATP concentrations were greatly reduced in both phases but P deficiency had no effect on protozoal numbers. The effects of P depletion during period II were similar to those of P deficiency in period I, and P repletion showed that the effects of P deficiency were almost entirely reversible.

Adenosine Triphosphate↗
PubMed1987

Isotypes of alpha-tubulin are differentially regulated during neuronal maturation.

The mRNAs for two isotypes of alpha-tubulin, termed T alpha 1 and T26, are known to be expressed in the rat nervous system. We have compared the expression of these two alpha-tubulin mRNAs during neural development, using RNA blotting and in situ hybridization techniques with probes directed against unique sequences of each mRNA. T alpha 1 mRNA is highly enriched in the embryonic nervous system but is markedly less abundant in the adult brain; T26 mRNA is expressed in many embryonic tissues with little change in abundance during development. Within the nervous system, T alpha 1 mRNA is enriched in regions with neurons actively undergoing neurite extension, such as the cortical plate, whereas T26 mRNA is relatively homogeneous in distribution, with some enrichment in proliferative zones. Expression of T alpha 1 mRNA is also increased in PC12 cells induced to differentiate and extend neurite processes by nerve growth factor. Taken together, the data indicate that T alpha 1-tubulin mRNA is expressed at high levels during the extension of neuronal processes. The abundant expression of T alpha 1-tubulin mRNA may therefore reflect either a means to increase the available pool of alpha-tubulin or a specific requirement for the T alpha 1 isotype for neurite extension.

Cell Differentiation↗
PubMed1987

Blood cultures in neonates with percutaneous central venous catheters.

We compared the results of 74 pairs of blood cultures obtained simultaneously every two weeks from a peripheral vein and a percutaneously inserted central venous catheter in 38 newborns. Three babies (7.9%) had bacteraemia. In two of these the central catheter was colonised 48 hours beforehand.

Blood↗