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Biomedical subjects

G Ducharme

Publications and source records attributed to G Ducharme.

At least 19 recordsLinked to original sources
PubMed1993

Predictive factors for spontaneous closure of atrial septal defects diagnosed in the first 3 months of life.

OBJECTIVES: To establish the rate of spontaneous closure of atrial septal defects diagnosed before age 3 months, 101 infants (mean age 26 days) with an interatrial shunt confirmed by Doppler echocardiography were followed up for an average of 265 +/- 190 days. BACKGROUND: Even if interatrial shunts in the newborn are frequently encountered, little is known about their natural history. METHODS: Defect diameter on two-dimensional echocardiography and width of color flow jet were measured in the subcostal view. Right and left ventricular diameters and atrial septal curvature were also studied. Kaplan-Meier curves were obtained to predict age of spontaneous closure in relation to initial defect diameter. RESULTS: There was no significant correlation between the diameter of the atrial septal defect and right ventricular/left ventricular ratio or type of septal curvature (vertical or concave toward the left atrium). The classic predominance of girls over boys was observed only for defects > 5 mm. An overall rate of spontaneous closure of 87% was observed. Frequency and timing of closure were inversely correlated to atrial septal defect diameter: closure occurred in 100% (32 of 32) of defects in group 1 (diameter < 3 mm), 87% of defects (39 of 45) in group 2 (diameter 3 to 5 mm), 80% of defects (16 of 20) in group 3 (diameter 5 to 8 mm). Spontaneous closure did not occur in four patients of group 4 (defect > or = 8 mm) during an average follow-up interval of 417 days (range 294 to 597 days). CONCLUSIONS: These results suggest that infants with an atrial septal defect < 3 mm need not be followed up as 100% of these defects will be closed by age 18 months; those with a defect 3 to 5 or 5 to 8 mm should be evaluated by the end of the 12th and the 15th month, respectively, when > 80% of these defects will be closed. An atrial septal defect with a diameter > or = 8 mm may have little chance of closing spontaneously and the possibility of surgical correction should be considered. Defects < 3 mm probably do not constitute a cardiac malformation in light of their natural evolution and gender distribution.

Age Factors↗
PubMed1992

Electrophysiologic effects of sotalol on the immature mammalian heart.

Sotalol is a beta-blocker with class III antiarrhythmic properties that has recently been used in children for the treatment of supraventricular and ventricular arrhythmias. However, little is known about its electrophysiologic effects on the immature heart. Using intracardiac electrocardiographic recordings and stimulation techniques, 15 canine neonates (8-15 days) and 15 adult mongrel dogs were studied with cumulative doses of sotalol (0.5, 1, 2, and 4 mg/kg plus an additional dose of 8 mg/kg for neonates). Heart rate decreased significantly in the two groups, but more in adult dogs (-43% in adult dogs versus -25% in neonates, p less than 0.05). There was no significant change for QRS duration and His-Purkinje system conduction time interval. QT and atrioventricular nodal conduction time intervals increased in adult dogs and neonates. Sinus node recovery time increased significantly in the two groups, but more in adult dogs. Refractory periods of the atrioventricular (AV) node increased significantly in neonates. Atrial flutter was no longer inducible in 12 of 15 neonates after the 2 mg/kg dose. Atrial effective refractory period increased significantly more in neonates (96%, p less than 0.001) than in adult dogs (58%, p less than 0.001). Ventricular effective refractory periods increased significantly both in neonates (46%) and adult dogs (50%), in a similar way. In conclusion, sotalol has greater electrophysiologic effects on the immature heart at the atrial level when compared to the adult, and similar effects on the refractory period of AV node and ventricle.

Animals↗
PubMed1992

A four-parameter generalization of the Gompertz curve suitable for somatic growth.

A four-parameter generalization of the Gompertz curve is proposed which passes through the origin with respect to total age and is often more suitable for somatic growth than the three-parameter Gompertz curve. Applied to published cross-sectional data on 44 male white rats, the new curve differs from another four-parameter curve proposed earlier by Jolicoeur and Pirlot (1988) in that it does not involve initial growth delays and it avoids an arbitrary assumption concerning the initial curvature, but it nevertheless yields approximately similar descriptions of chronological growth and complex allometry. The new four-parameter version of the Gompertz curve may be useful in cases where other growth curves do not provide a satisfactory fit.

Animals↗
PubMed1990

Frequency and prognosis of arrhythmias after operative "correction" of tetralogy of Fallot.

Two hundred twenty-four consecutive patients operated on for tetralogy of Fallot were followed from 1 to 28 years (mean 11). Mean age at surgery was 5.3 years (range 1 to 14). Postoperative right ventricular systolic pressure was 60 mm Hg in 19 of 213 patients (9%). Fourteen patients (6%) had ventricular premature complexes on surface electrocardiograms. Seventy-nine patients underwent treadmill exercise tests, and ventricular premature complexes were induced in 17 (22%). Twenty-four-hour ambulatory monitoring in 92 patients demonstrated significant ventricular arrhythmias (greater than or equal to grade 2 of the Lown classification) in 41 (45%). The frequency of ventricular arrhythmias correlated with length of follow-up and duration of cardiopulmonary bypass. No correlation was found with age at surgery, postoperative right ventricular systolic pressure and importance of conduction defects on electrocardiogram. There were no sudden or unexpected deaths during follow-up.

Adolescent↗
PubMed1988

Left ventricular diastolic function during the first month of life.

UNLABELLED: In order to assess possible changes in myocardial relaxation occurring during the neonatal period, M-mode echocardiograms were recorded serially in 9 normal term infants and in another group of 10 one-month-old infants. The tracings were studied with an M-mode calculator. Although individual variations were greater in the data collected during the first 24 h, no significant difference was found in the indices of diastolic function of the left ventricle during the first 4 days of age. The following changes were observed between data recorded at 4 days and 1 month, respectively: normalized peak rate of left ventricle filling, 4.03 vs. 4.71 cm/s; diastolic peak velocity of early posterior motion of aortic root, 1.89 vs. 5.15 cm/s; peak velocity of left ventricle posterior wall motion in diastole, 3.31 vs. 3.50 cm/s; mitral valve EF slope, 59.05 vs. 84.92 mm/s; left ventricle isometric relaxation time, 43.88 vs. 28.50 ms. IN CONCLUSION: (1) greater individual variations are observed in indices of left ventricle diastolic function during the first day of life, and (2) significant increase in left ventricle compliance occurs during the first month of life. These changes should play a critical role in the clinical course of newborn with cardiopulmonary disease.

Diastole↗
PubMed1988

Cardiac rejection following transplantation in dogs: transmural myocardial blood flow changes.

In cardiac allografts acute rejection produces deleterious effects on blood flow adjustments. In order to differentiate the role of rejection over that of denervation cardiac denervated and cardiac transplanted dogs were compared. A canine model of orthotopic cardiac transplantation was utilized. Electronic devices were implanted for chronic hemodynamic studies. Regional myocardial blood flow distribution was assessed by radioactive microspheres (15 micron in diameter). Studies were carried out when animals had fully recovered (two to three days postoperatively), then in the 'early rejection' stage (five to six days post transplant) and in the 'severe rejection' stage (24 h before death). No significant difference in hemodynamic data or blood flow values were observed between groups in the recovery stage. In the denervated group, adequate cardiac function and myocardial blood perfusion was maintained throughout the study. In the transplanted group, significant loss of function was observed at the severe rejection stage. This was combined with significant decrement in blood flow to all areas of the myocardium. No selective area of underperfusion nor an early reduction in total blood flow could be observed. This study indicates that within cardiac rejection there is a parallel impairment in function and transmural myocardial blood flow which is unrelated to denervation or interruption of lymphatics.

Animals↗
PubMed1986

Value of respiratory variations of right ventricular dimension in the identification of small atrial septal defects (secundum type) not requiring surgery: an echocardiographic study.

In search of reliable criteria that could help differentiate insignificant atrial septal defects (ASDs) from those with a large shunt, M-mode echocardiograms of three groups of patients were studied retrospectively: group I = 10 normal children (mean age 5.7 years); group II = 10 patients (mean age 7 years) with small ASD in whom the decision was taken not to proceed to surgical closure, based on hemodynamic and angiographic criteria; and group III = 15 patients (mean age 7 years) with an "operable" shunt, who underwent corrective surgery. The results showed that right ventricular end-diastolic dimensions during expiration (RVDDE) were increased in all patients in group III but were normal in only 3 of the 10 patients in group II. A normal septal movement was found in all patients in groups I and II but also in five patients in group III. The variation in right ventricular diastolic dimension with respiration (RVDVR) was always normal in group II. However, in group III all patients but one had a small RVDVR (less than 6%). It was concluded that a normal RVDDE is very specific (100%) but not sensitive (30%), a normal septal movement is very sensitive (100%) and moderately specific (70.6%), and a normal RVDVR is both very sensitive (100%) and specific (94.4%) as a criterion for identification of small ASDs not requiring surgery.

Adolescent↗
PubMed1986

Wall thickness, cavity dimensions, and myocardial contractility of the left ventricle in patients with simple transposition of the great arteries. A multicenter study of patients from 10 to 20 years of age.

Fifty-one patients with uncomplicated transposition of the great arteries (TGA) and normal pulmonary pressure who were 10 to 20 years old and 69 normal subjects matched for age were studied by M mode echocardiography. Left ventricular internal dimensions and posterior wall thickness showed positive correlation with the body surface area in the TGA as well as in the control groups. Values for these parameters in the TGA group were generally smaller than those in the normal population. Septal thickness of patients with TGA (5.9 +/- 1 mm) was also smaller than that in the control group (6.6 +/- 1 mm) (p less than .01). Septal motion was normal in 11 patients with TGA and paradoxical in 19 patients in this group. In the other 21 patients the septum was flat. The following systolic time intervals of the left ventricle were found for patients with TGA: preejection period (PEP) 64 +/- 11 msec, ejection time (ET) 310 +/- 37 msec, and PEP/ET 0.21 +/- 0.04. These values were significantly different from those of the right ventricle for the normal population: PEP 77 +/- 12 (p less than .01), ET 327 +/- 25 (p less than .05), and PEP/ET 0.24 +/- 0.03 (p less than .01). Shortening fraction and mean velocity of circumferential fiber shortening (49 +/- 7% and 1.6 +/- 0.3 circ/sec, respectively) were also significantly higher (p less than .01) in patients with TGA than in the control group (33 +/- 4% and 1.1 +/- 0.2 circ/sec). These data should help achieve reliable quantitative and qualitative interpretations of echocardiograms of patients with TGA.

Adolescent↗
PubMed1986

Myocardial function and hemoglobin oxygen affinity during hyperglycemia in the fetal lamb.

To determine the effects of maternal hyperglycemia on fetal hemodynamic and cardiac function, a study was carried out on nine chronically catheterized fetal sheep. In six fetuses, glucose was infused intravenously with an initial dose of 5 mg/kg per min. Data were compared with controls. This dose was gradually increased to 16 mg/kg per min by the fifth day. The initial blood glucose was 14.7 +/- 3.0 mg/dl and increased to 54.6 +/- 16.4 mg/dl by the last day of the infusion period (P less than 0.001). The PO2 decreased from a baseline of 20.25 +/- 3.40 to 15.88 +/- 5.24 mmHg (P less than 0.01). Similarly significant decreases were also observed for the blood O2 content and O2 hemoglobin saturation: 8.5 +/- 1.7 to 6.4 +/- 2.2 ml/dl and 62.3 +/- 13.6 to 46.1 +/- 17.6%, respectively, during hyperglycemia (P less than 0.01). The duration of the preejection period (PEP) before the start of the experiment was 45 +/- 4 ms; a final value of 57 +/- 10 ms was obtained (P less than 0.01). However, the electromechanical delay and ejection time (ET) showed no significant variation. The ratio of the PEP/ET increased from 0.31 +/- 0.04 to 0.38 +/- 0.07 (P less than 0.01) during hyperglycemia. The reticulocytes increased from 1.4 +/- 1.8 to 3.1 +/- 2.9% (P less than 0.05) and the 2,3-diphosphoglycerate decreased from 4.4 +/- 1.1 to 2.8 +/- 1.2 mumol/g hemoglobin (P less than 0.005). This study demonstrated that fetal hyperglycemia depresses myocardial function in the fetal lamb. The changes in cardiac function could not be explained by the small drop in O2 saturation.

2,3-Diphosphoglycerate↗
PubMed1986

Psychomaintenance of childhood asthma: a study of 34 children.

Following the study on psychomaintenance of asthma by Kinsman, Dirks, and Jones (1977), we adapted the Battery for Asthma Illness Behavior (BAIB) to children. Thirty-four children aged 9.3 to 15.4 years were tested with this modified BAIB. They were scored simultaneously on a semistructured psychological interview. Three groups emerged out of these data: low-, medium-, and high-panic-fear personalities. Patients were also rated with regard to their pulmonary function and clinical status, including medication prescribed. The high-panic-fear personality was significantly associated with a higher intensity of prescribed medication, in particular corticosteroids. These results were independent of spirometric pulmonary measurements. We conclude that doctors may overreact to the exaggerated distress of high-panic-fear patients. Psychotherapy could be of help for this group.

Adolescent↗
PubMed1986

[Treatment of acute perforated appendicitis with intraperitoneal cefazolin].

Until recently intra-abdominal sepsis following surgery for perforated appendicitis has remained a frequent occurrence. In 1975 Fowler reported an incidence of one intra-abdominal abscess in 36 perforated appendicitis treated with a protocol consisting of saline irrigation at surgery, followed by intraperitoneal administration of cephaloridine q. 6 hours for 48 hours. The same antibiotic was then given i.v. for 72 hours. He concluded that this method was an effective way to minimize post-op intra-abdominal abscess, and that the intraperitoneal route was more effective, for this purpose, than systemic administration. More recently, with better knowledge of the role of anaerobes, improved results have also been obtained by adding clindamycin or metronidazole to the antibiotic regimen. A prospective study based on two groups of patients randomly assigned to two protocols was undertaken. The study group consisted of 45 children operated for perforated appendicitis with abscess or generalized peritonitis. These patients were treated with Fowler's protocol. Because it is less nephrotoxic and is active against the same organisms, cefazolin was used instead of cephaloridine. The control group consisted of 43 patients, also operated for perforated appendicitis, treated with saline irrigation at surgery, with either i.v. gentamycin or tobramycin and clindamycin or metronidazole for an average of 7.8 +/- 3.1 days. Both groups were fairly well matched in terms of age, sex, severity of disease, and bacterial flora. They showed an identical 6% post-op intra-abdominal sepsis rate. Days before afebrile, days under gastric suction, complications and average hospital stay were comparable in both groups. The wound infection rate was 20% in the study group and 9% in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗
PubMed1985

Effects of maternal alcohol intoxication on fetal circulation and myocardial function: an experimental study in the ovine fetus.

To determine whether acute alcohol ingestion during pregnancy could affect fetal myocardial function, studies were carried in six chronically catheterized fetal sheep during maternal alcohol infusion. Absolute ethyl alcohol (0.8 ml/kg) was administered to the mother over 10 minutes via the jugular vein. These infusions were repeated every 30 minutes during 3 hours, and peak maternal and fetal blood concentrations close to 200 mg/dl alcohol were reached. Fetal PCO2 decreased from a baseline of 43.15 +/- 3.75 to 36.13 +/- 2.6 torr 1 hour after the start of alcohol infusion (P less than 0.05). Similarly, pH rose from 7.37 +/- 0.027 to 7.44 +/- 0.015 (P less than 0.05). Both values returned to baseline level at the end of alcohol infusion. PO2 remained within physiologic limits. The systolic time intervals of the fetal heart showed a rapid and prolonged modification. The pre-ejection period from 58 +/- 8 to 66 +/- 4 msec (P less than 0.05) during the infusion; this change was related to an increase in the isometric contraction period. The ratio of the pre-ejection period over the ejection time was also significantly increased (P less than 0.01), and remained elevated until the end of the experiment (12 hours). A rise in fetal systolic and diastolic pressures was observed at about 2 hours after the start of the alcohol infusion, and lasted 4 hours. This study suggests that an episode of maternal alcohol intoxication causes rapid depression of fetal myocardial contractility that is maintained several hours after cessation of alcohol ingestion.

Alcoholic Intoxication↗
PubMed1985

[Respiratory variations in the right ventricular diameter: an echocardiographic element in the diagnosis of partial isolated pulmonary venous return anomaly].

Isolated partial anomalous pulmonary venous drainage (PAPVD), in contrast to atrial septal defect (ASD), does not cancel out the effects of respiration on blood flow in the right ventricle. The aim of this study was to see whether this difference could contribute to the diagnosis of PAPVD without ASD on M mode echocardiography. The diastolic dimensions of the right ventricle on expiration and inspiration were compared in 4 groups of patients aged 2 to 17 years. Group 1 comprised 6 children with PAPVD without ASD; Group 2: 10 children with PAPVD and ASD; Group 3: 11 children with isolated non-restrictive ASD, and Group 4: 10 normal children. Groups 1 and 4 were comparable with a respiratory variation of RV dimension of 10 to 29%. On the other hand, in Groups 2 and 3 the percentage variation was less than 6%. The finding of isolated RV dilatation with normal respiratory variation of its internal dimension should therefore alert the operator to the possible diagnosis of PAPVD without ASD.

Adolescent↗
PubMed1984

Date of conception and prevention of neural tube defects.

The authors studied the time of conception of 280 fetuses and liveborns with anencephaly or spina bifida seen in a French Canadian population during a period of six years. There is an evident seasonal variation in the conception of NTD fetuses. Using a wave statistical model applied to data recorded over a six year period the authors have rejected the "no variation between the six two-month intervals" hypothesis at a P less than or equal to 0.005 level. It is postulated that, in any vitamin intake or environmental program to prevent NTD in families at risk, one must take into account the annual and seasonal variations, ethnic groups identity and the date of conception in the choice of control mothers.

Canada↗
PubMed1983

Past infectious events and disease evolution in multiple sclerosis.

A computerized study of past infectious events and neurological parameters revealed the existence of a history of repeated respiratory-tract infections (RRI) beginning in childhood, in 52% of 251 multiple sclerosis (MS) patients studied. The 251 MS patients were divided into two groups: those without a past history of RRI were designated as "MS type I", and those with a history of infectious problems before the onset of MS as "MS type II". Significant differences in the neurological symptoms, the treatment received and some general parameters were found between the groups, which suggested a correlation between the evolution of MS and the presence or not of RRI in these patients. When compared to the MS type I group, a significantly higher percentage of MS type II patients reported visual problems (P less than or equal to 0.01), paresthesia (P less than or equal to 0.01), loss of sensitivity (P less than or equal to 0.03), pain (P less than or equal to 0.004), motor problems (P less than or equal to 0.016) and sexual dysfunction in males (P less than or equal to 0.02). The mean number of attacks in the first 5 years of the disease was significantly more frequent in MS type II patients, 6.2 compared to 2.9 (P less than or equal to 0.02). A significantly higher percentage of MS type II patients also received oral corticosteroids (P less than or equal to 0.02) or ACTH (P less than or equal to 0.003). Although the age of onset of MS was the same for both groups, MS type II patients were significantly younger than MS type I patients, the mean age being 36 years compared to 41 years (P less than or equal to 0.001). Only 12% of patients in the MS type II group compared to 30% in the MS type I group had the disease for more than 15 years (P less than or equal to 0.001). As is usual with MS, the majority of the patients in both groups were females, 79.3% in the MS type II compared to 63.4% in the MS type I group. These findings suggest that MS patients with a past history of RRI (MS type II) have a different evolution of their disease from MS type I patients and that in general the disease is more severe. The past infectious history of patients would thus appear of putative value, in addition to neurological criteria, in assessing the probable future evolution of the disease.

Adrenal Cortex Hormones↗
PubMed1983

Echocardiographic assessment of cardiac function in children with chronic renal failure.

Echocardiographic assessment of cardiac function was made on 24 children with chronic renal failure of varying etiology and severity. In 20 patients without evidence of cardiac failure, parameters of left ventricular performance as represented by PEP/LVET and mean velocity of circumferential fiber shortening were within normal limits in the majority of patients. In addition, ejection fraction and shortening fraction were, in most children, within the 95% confidence limits for their age. In 4 patients who presented with congestive heart failure, marked left ventricular dilatation was noted in association with decreased shortening and ejection fractions and depressed mean velocity of circumferential fiber shortening. Also the PEP/LVET in these patients suggested the presence of a uremic cardiomyopathic condition. These studies, in addition to our own studies on children who have undergone fistula construction, hemodialysis, and transplantation, suggest that cardiac performance, in the majority of pediatric patients with end-stage renal disease, is well maintained and that the major factor involved in reducing exercise tolerance is the presence of uremic anemia. Only a minority of patients may develop severe uremic heart disease.

Adolescent↗
PubMed1982

Maternal alphafetoprotein screening by the polypropylene tube immunoradiometric assay on dried blood.

The polypropylene tube immunoradiometric assay for alphafetoprotein (AFP) determination was applied to maternal serum along with a radioimmunoassay technique during the second trimester of pregnancy. Blood from pregnant women was collected by finger prick on strips of chromatography paper (Schleicher and Schuell No. 903C) and air dried. A 4.75 mm disc spot was eluted in anti-AFP coated tubes containing 1.0 ml of assay medium. After one hour the medium was vortexed and the tubes washed and counted on a Concept 4tm (Micromedic Systems, Horsham, PA. 19044). The sensitivity of the technique is about 9 micrograms/l (35 ng/l in the assay) by the Rodbard formula. The concordance between the dried blood and the serum RIA tests in normal pregnancies was over 90 per cent at the 95th and 97th percentiles. This assay on dried blood spotted on chromatography paper was tested on 1003 patients and proved to be an ideal alternative to whole serum screening techniques: it minimizes sample manipulations and can easily be integrated into an existing newborn screening programme.

Female↗