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Biomedical subjects

C Marchal

Publications and source records attributed to C Marchal.

At least 109 records · Page 6Linked to original sources
PubMed1991

[Right pulmonary artery arising from the proximal ascending aorta. A model of reflex pulmonary hypertension of the left lung?].

The right pulmonary artery arising from the proximal ascending aorta is a rare and severe malformation. This retrospective study of 11 children with this condition was undertaken to determine the conditions of diagnosis, to analyse the results of surgery, and, above all, to clarify the mechanism of the left pulmonary arterial hypertension which was always present. Ten of these patients were 4 to 90 days old. All had severe congestive cardiac failure with iso- or suprasystemic left pulmonary arterial hypertension. The only associated lesions were ventricular septal defect (1 case) and patent ductus arteriosus (7 cases). None of the patients had significant left-to-right shunts and only one had left atrial hypertension: this patient died before surgery could be performed. The other 9 patients underwent surgical correction and the pulmonary pressures immediately fell to normal or almost normal values. The child with the ventricular septal defect died of infection 6 weeks after surgery. The 8 survivors are doing well 1 month to 12 years later and left pulmonary pressures are normal in all, including those (5 cases) with a stenosed (4 cases) or completely occluded right pulmonary arterial circulation (1 case) and in 1 patient with obstructive vascular disease. The eleventh patient was very different: she had no signs or symptoms until 2 years of age, when a right pulmonary obstructive arterial disease but with normal left pulmonary pressures was documented. She was not operated on and remains well nine years later.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1990

Improvement of radioactive colloid binding by tumor cells.

Treatment of P388 leukemia cells with poly-DL-lysine (Poly-lys) considerably increases the binding of colloidal chromic phosphate (32P). This augmentation of the number of particles that are bound is in direct relationship with Poly-lys concentration, and very significantly with its degree of polymerization. Treatment with Poly-lys molecular weight 77,000 shows a 100% increase of binding with 200 micrograms and of 50% with 100 micrograms. Poly-lys M.W. 8,000 presents no significant increase, and for the other molecular weights the binding is intermediate.

Adsorption↗
PubMed1990

Ventricular couplets in the young: prognosis related to underlying substrate.

Ventricular couplets may be a risk factor for sudden death in adults, but their prognosis in children is unknown. From 1981 to 1987 104 patients, mean age 13.2 years (0.2 to 37 years), had ventricular couplets on a 24-hour electrocardiogram (ECG) (Holter monitor) and on follow-up with a second Holter (mean, 2.5 years). Of the 104 patients, 22 had a normal heart and 82 had an abnormal heart. Patients with a normal or an abnormal heart did not differ in incidence or severity of symptoms (patients with a normal heart had 17 instances of palpitations and none of syncope; patients with an abnormal heart had 49 instances of palpitations, six of dizziness, and none of syncope). Number of ventricular couplets was higher in patients with a normal heart (33 +/- 50/day: mean +/- 1 SD) than in those with an abnormal heart (17 +/- 15/day; p less than 0.05). Of the 22 patients with a normal heart, 11 underwent an electrophysiologic study (EPS); none had inducible ventricular tachycardia. After mean follow-up of 29.7 months, all 22 patients with a normal heart were alive without ventricular tachycardia; 6 of 22 were treated for palpitations, with complete suppression of couplets in two. In 11 of 16 untreated patients with a normal heart, ventricular couplets disappeared spontaneously. Of the 82 patients with an abnormal heart, 32 had an EPS: nine (28%) had sustained ventricular tachycardia, 16 (50%) had nonsustained ventricular tachycardia, and seven (22%) had no inducible ventricular tachycardia. ECG criteria and hemodynamic status were of limited value in predicting inducibility of ventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Conservation of Neisseria gonorrhoeae pilus expression regulatory genes pilA and pilB in the genus Neisseria.

The pili of Neisseria gonorrhoeae mediate bacterial adhesion to the host-susceptible tissues. We have previously reported the identification of two genes, pilA and pilB, which act in trans to regulate pilus expression. Besides this regulatory function, pilA participates in an essential function for bacterial viability. Here we show that pilA and pilB homologs are also present in a variety of other members of the Neisseriaceae family of bacteria in contrast to the gonococcal pilin gene which hybridizes only to the pathogenic Neisseria species.

Bacterial Outer Membrane Proteins↗
PubMed1989

3M dwarfism: a study of two further sibs.

Two sibs are reported with clinical and radiological features of the 3M syndrome. The differential diagnosis is discussed, particularly with regard to Russell-Silver syndrome.

Consanguinity↗
PubMed1988

Pilin expression in Neisseria gonorrhoeae is under both positive and negative transcriptional control.

We have identified two closely linked genes, pilA and pilB, which act in trans on the pilin promoter. pilA-pilB map downstream of expression loci pilE1 and opaE1 in the gonococcal chromosome. Subcloning data indicate that pilB acts negatively on the pilin promoter, and insertional inactivation of pilB results in hyperpiliated gonococci. A pilA clone activates the pilin promoter in Escherichia coli, and a pilA-/pilA+ heterodiploid gonococcus exhibits a P- phenotype. Our inability to obtain simple pilA- mutants strongly suggests that pilA is an essential gene in the gonococcus. In an in vitro coupled transcription/translation system, inserts spanning the pilA and pilB region direct the synthesis of two proteins of 40 and 58 kd. DNA sequence analysis shows that the pilA and pilB loci encode proteins of 38.6 kd (with a putative DNA binding domain) and 57.9 kd respectively. The pilA and pilB genes are in opposite orientation relative to each other, and the 5' ends of the two genes overlap. We discuss how these two loci may interact to control pilin expression in the gonococcus.

Amino Acid Sequence↗
PubMed1988

DNA transformation leads to pilin antigenic variation in Neisseria gonorrhoeae.

Many pathogenic bacteria express pili (fimbriae) on their cell surfaces. These structures mediate binding of bacteria to host tissues, and may also be involved in other aspects of pathogenesis. Neisseria gonorrhoeae pili are mainly composed of a single protein, pilin, whose expression is controlled at chromosomal expression loci (pilE). An intact pilin gene and promoter sequences are only found at pilE. Strain MS11 contains two expression sites (pilE1 and pilE2), whereas several of its derivatives and other clinical isolates contain only one. Silent pilin loci (pilS1-pilS7) contain truncated variant pilin genes lacking the promoter and conserved pilin gene sequences. Pilin antigenic variation in N. gonorrhoeae occurs by DNA recombination between one of he silent partial variant gene segments in pilS and an expressed pilin gene in pilE. The recombination reactions are nonreciprocal, and therefore the mechanism has been classified as gene conversion. We report that much of the recombination between pilin loci actually occurs after transformation of living piliated cells by DNA liberated from lysed cells within a population. This constitutes a new molecular mechanism for an antigenic variation system, as well as the first specific function for a DNA transformation system.

Antigenic Variation↗
PubMed1988

Determinants of compliance in epileptic patients.

A questionnaire was filled out by 270 epileptic outpatients responsible for taking their own medication to assess the extent of drug compliance-adherence and look for factors associated with poor compliance. Eighty-six patients (31.8%) were considered non-compliers. Significant factors for non-compliance were a duration of disease from 10 to 20 years, a low frequency of seizures and a drug intake considered as very bothersome. Neither sex nor age at onset, nor age at survey, nor type of epilepsy were different in compliers and non-compliers. Stopping medication to see if one is cured was more frequent in women than in men and a fear of drug toxicity was more frequent in patients over 30 years old.

Adolescent↗
PubMed1987

Stroke risk in patients with carotid stenosis.

In 242 neurologically symptomless patients with at least one non-occlusive carotid stenosis on ultrasonography (continuous wave doppler and echotomography-B mode imaging) 171 carotids showed 0-50% stenosis, 150 showed 50-75% stenosis, and 78 showed more than 75% stenosis. The mean follow-up was 29.4 months, with stroke and death as end points. Of the 56 deaths 2 were causally linked to a stroke (crude annual mortality index 9.57%). Of the 10 strokes 7 were judged to be infarctions in carotid territory. 7 out of 20 patients with transient ischaemic attacks (TIA) had ischaemic symptoms definitely related to carotid territory. The crude annual indices of specific stroke or TIA were 0.45% for nonstenotic carotid, 0.23% for 0-50% stenosis, 2.48% for 50-75% stenosis, and 1.71% for 75-99% stenosis. Stenoses of greater than 50% were associated with more ischaemic events than were lesser degrees of narrowing (p less than 0.01).

Aged↗
PubMed1987

[Effects of intravenous nicardipine on blood pressure, hemorheology platelet function in arterial hypertension. Dose-effect relations].

In arterial hypertension, hyperviscosity with hemorheological disturbances and platelet dysfunction may play a role in the prognosis and complications of the disease. We studied the effects of Nicardipine (NIC) on these blood disturbances in a group of 21 untreated patients with essential hypertension, aged 25 to 70 years (SBP/DBP = 185 +/- 28/105 +/- 17 mmHg). During one hour before and 4 hours after the IV injection of single doses of 5, 7.5 or 10 mg NIC over 5 min, blood pressure was recorded automatically (Dinamap). Hemorheological variables and platelet function were studied before and 30 min, 3 h and 24 hours after the injection. NIC lowered blood pressure and increased heart rate significantly (At 5 min, SBP = -24 mmHg; DBP = -18 mmHg; HR = +22 b/min). These effects were dose-dependent with rapid onset and short duration (less than 2 hrs). NIC decreased plasma viscosity from 1.36 +/- 0.08 to 1.30 +/- 0.07 Cst; p less than 0.01, whole blood viscosity from 22.4 +/- 2.8 to 20.7 +/- 1.5 mPas; p less than 0.05 for gamma = 0.512 s-1, and erythrocyte filterability with the Ca++ ionophore A 23187 from 16.3 +/- 3.8 to 13.5 +/- 3.1; p less than 0.01. Platelet aggregation with ADP was unchanged, but aggregation with A 23187 decreased from 46.9 +/- 21.2 to 31.3 +/- 25.6; p less than 0.05, as well as plasma levels of beta-thromboglobulin (71.2 +/- 29.8 to 55.4 +/- 24.3 ng/ml; p less than 0.02) and platelet generated malonaldehyde (7.2 +/- 1.8 to 6.7 +/- 1.4 nM/10(9) platelets; NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Hyperthermia inhibition of tumor cells growth in the presence of ruthenium red.

Ruthenium red (RR) is taken up by DS sarcoma cells as a linear function of its concentration. Higher temperatures produce a higher uptake. This increased uptake is coincident with an augmentation of Trypan blue inclusion. A diminution of calcium transport in the presence of RR is observed at hyperthermia, and its uptake is not linear but presents a plateau for all temperatures and concentrations. RR-cell membrane interaction seems to produce two different effects: an early blocking of calcium transport, and a later change of the physicochemical characteristics of the plasma membrane. On the colony forming ability of CA1 cell RR shows clearly an intrinsic toxic effect, and when present during hyperthermia a low but significant enhancement of tumor cells mortality.

Animals↗
PubMed1986

[Hemodynamic effects of an alpha-blocking vasodilator in cardiac insufficiency caused by left-right shunt in children].

The acute haemodynamic effects of an alpha-blocking vasodilator, nicergoline, observed during cardiac catheterisation were studied in 9 babies and 1 infant (mean age 11 months) with severe cardiac failure due to a large left-to-right interventricular shunt. Nicergoline was administered intravenously at a dose of 0.05 mg/kg/mn to 0.2 mg/kg/mn to lower mean systemic blood pressure by at least 10 mmHg. No significant changes in heart rate or in right and left atrial pressures were observed. On the other hand, mean systemic and pulmonary arterial pressures fell by 16% (p less than 0.001) and 13% (p less than 0.01) respectively. The ratio of pulmonary and systemic flow (Qp/Qs) decreased in 8 patients by an average of 21% (p less than 0.002). This fall was accompanied by a parallel reduction in oxygen concentrations of pulmonary arterial blood (16%) compared with mixed venous blood. However, the Qp/Qs ratio increased in the other 2 patients by over 50%. In the group of 8 patients in which the left-to-right shunt decreased, the ratio of pulmonary to systemic resistance (Rp/Rs) increased by 33% (p less than 0.002) whilst this value fell by 36% in the 2 patients in whom the volume of the shunt increased. There were no discriminatory parameters between the two groups with regards to age, pulmonary artery pressures, the volume of the shunt (Qp/Qs) or level of pulmonary resistances (Rp/Rs) to explain the variability of the therapeutic response on the left-to-right shunt.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1986

[Measurement by Doppler echocardiography of the pulmonary arterial pressure in children with ductus arteriosus. Simultaneous Doppler and hemodynamic study].

The aim of this study was to evaluate Doppler echocardiography in the non invasive assessment of pulmonary artery pressures in children with patent ductus arteriosus. Systolic pulmonary artery pressure was measured simultaneously at cardiac catheterisation and by pulsed Doppler in 11 children (mean age 1.8 +/- 2 years) with patent ductus arteriosus alone (6 cases) or associated with a malformation of the heart or great arteries (5 cases). Doppler assessment of systolic pulmonary artery pressure was performed by subtracting the value of the maximal pressure gradient between the aorta and pulmonary artery from the systolic systemic pressure measured simultaneously by sphygmomanometry. The maximal pressure gradient between the aorta and pulmonary artery was calculated using the modified Bernouilli formula and the maximal velocity (v) of the shunt flow (gradient = 4 v2). Ductal flow was recorded from the suprasternal approach by direct interrogation of the patent ductus visualised by 2D echocardiography. The systolic pulmonary arterial pressure measured by catheterisation ranged from 21 to 82 mmHg (mean 58 +/- 21 mm Hg) and by pulsed Doppler from 20 to 89 mm Hg (mean 56 +/- 24 mm Hg) (correlation r = 0.94). This study illustrates the value of Doppler echocardiography in the assessment of systolic pulmonary artery pressures in children with patent ductus arteriosus.

Blood Pressure Determination↗
PubMed1985

Calcium, calcium-ATPase and cyclic AMP changes in Ehrlich ascites cells submitted to hyperthermia.

Increased radiocalcium influx, decreased Ca-ATPase activity and cAMP concentration were observed in Ehrlich carcinoma cells submitted to hyperthermia temperature (45 degrees C). The significant augmentation of mitochondrial calcium that is simultaneous to an inhibition of the calcium pump appears to indicate a heat-induced failure of the system of calcium-extrusion that may be responsible for cell inactivation and death through cell toxic death by calcium overloading. The decreased cAMP concentration appears to corroborate the influx of calcium.

Animals↗
PubMed1985

[Relative values of carotid ultrasonic diagnosis and the Doppler test].

The rapid development of techniques for vascular imaging raises questions as to the hierarchy of exploratory non-invasive investigations of cervical vessels. However, caution is necessary when interpreting data provided by different teams because of the unequal experience in the use of these methods by the teams and the variable quality of the apparatuses used. A general rule should be to avoid dissociating imaging and Doppler. Too many teams give priority to ultrasound because of its simplicity in use and the apparent quality of data supplied. However, errors may arise from the weak reflectivity of soft plaques, particularly recent clots, from an acoustic shadow associated with some calcified plaques and from an unfavorable position of the lesion in relation to possible section planes. These problems increase when the apparatus is poorly adjusted, when resolution is insufficient or when there is a threshold to the detection of echos.

Arteriosclerosis↗