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Biomedical subjects

J C Jéquier

Publications and source records attributed to J C Jéquier.

At least 19 recordsLinked to original sources
PubMed1999

Sonographic nomogram of the leptomeninges (pia-glial plate) and its usefulness for evaluating bacterial meningitis in infants.

BACKGROUND AND PURPOSE: To our knowledge, the upper limits of the thickness of normal meninges on neurosonograms are not known. We therefore established a nomogram for sonographic measurements of the leptomeninges (pia-glial plate) and assessed its usefulness in neurosonographic examinations of children with bacterial meningitis. METHODS: The pia mater-cortical glia limitans complex on the surface of the brain and in the sulcus of a frontal gyrus was measured on neurosonograms in 100 infants without meningeal disease in order to establish a nomogram of the thickness of this pia-glial plate, referred to as the leptomeninx. Effects of prematurity, age, sex, and single-layer (surface) versus double-layer (sulcus) measurements were analyzed. Meningeal thicknesses derived from a retrospective analysis of the neurosonograms of 33 patients with purulent meningitis and a prospective study of 22 patients with bacterial meningitis were compared with the nomograms. Clinical outcomes of children with meningeal thickening were compared with those of affected children with normal meninges. RESULTS: The distribution of sulci measurements was significantly asymmetrical around the mean. Statistical data showed no influence of prematurity and sex, but showed surface measurements to be more consistent than sulcal measurements. Older chronological age was related to slightly larger sulci, but did not influence the surface measurements. In children with bacterial meningitis, the surface meninges were less frequently thickened than were the sulci. Sulcal enlargement occurred often in combination with echogenic deposits in the sub-arachnoid space. CONCLUSION: Leptomeninges are best measured on the surface of a gyrus rather than in a sulcus, as the normal thickness of the sulci shows much more variability. Clinical outcome of bacterial meningitis cannot be predicted by presence or absence of meningeal thickening as the only sonographic abnormality.

Echoencephalography↗
PubMed1998

Acute childhood pyelonephritis: predictive value of positive sonographic findings in regard to later parenchymal scarring.

RATIONALE AND OBJECTIVES: The authors evaluated the importance of positive sonographic findings in acute childhood pyelonephritis. MATERIALS AND METHODS: A total of 290 children (91 boys, 199 girls, aged 4 days to 15 years [median, 394 days]) with clinically suspected acute pyelonephritis underwent initial renal gray-scale ultrasound (US) and dimercaptosuccinate scintigraphic examination within 3 days of onset. A total of 173 patients underwent color or energy US examination. One hundred fifteen children with normal scintigraphic or pathologic findings (other than acute pyelonephritis) were excluded from further study; 170 patients with abnormal scintigraphic findings underwent follow-up scintigraphic scanning 60-90 days later. RESULTS: When pathologic structures other than acute pyelonephritis were not considered, the diagnostic value of gray-scale US was poor, with a sensitivity of 45.5%, a specificity of 86.6%, a positive predictive value of 88.8%, and a negative predictive value of only 40.6%. In regard to future renal scarring, gray-scale US had a positive predictive value of 67.7%, a negative predictive value of 40%, and a likelihood ratio of 1.16. Abnormal Doppler findings helped predict future scarring with a positive predictive value of 85.7%, a negative predictive value of 37.2%, a very low sensitivity of 26.9%, a high specificity of 90.6%, and a likelihood ratio of 2.87. CONCLUSION: Positive US Doppler findings in children with clinically suspected acute pyelonephritis indicate the need for immediate treatment. A positive initial gray-scale US examination does not predict future renal scarring, but a positive Doppler examination indicates a high probability of scarring. Negative gray-scale or Doppler US does not exclude a diagnosis of acute pyelonephritis and it cannot predict an absence of future scarring.

Acute Disease↗
PubMed1997

Study of psychosocial parameters related to the survival rate of renal transplantation in children.

The purpose of the present study was to assess the effect of intelligence, schooling, psychomotor, emotional, and social status on renal graft survival in children. Sixty-two cadaver renal transplant recipients were evaluated retrospectively and the influence of sex, age, weight, and the use of cyclosporin A (CyA) on the success rate of the graft from 1 to 5 years later was analyzed. Psychological and social scores were devised and included as factors predictive of survival of the graft. Univariate analysis showed that the following variables predicted renal graft survival: the use of CyA (P = 0.0002), pre-transplant dialysis (P = 0.04), weight at the time of transplantation (P = 0.072), and psychological scores (P = 0.064). Association analysis demonstrated that pre-transplantation dialysis was only a chance association and therefore the parameter was discarded. Multivariate analysis showed that the predictive parameters were the use of CyA, sex, weight in kilograms, and the psychological score. An equation was then derived from variables that predict the probability that a specific patient's graft will survive more than t months. This equation is the estimated survival distribution function and is as follow: S (t) = Exp {-Exp[-(0.8882x1 - 1.827x2 + 0.037x3 - 0.1746x4) + ln t - 4.7862]} where S (t) = the survival at t months post transplantation, x1 = sex (male 1, female 2), x2 = CyA (yes 1, no 2), x3 = weight in kilograms, and x4 = psychological score. The major impact of psychological factors on renal graft survival was surprising.

Adolescent↗
PubMed1996

Diagnostic accuracy of technologies used in low back pain assessment. Thermography, triaxial dynamometry, spinoscopy, and clinical examination.

STUDY DESIGN: A prospective blind study compared three new technologies to assess back pain. OBJECTIVE: To assess the diagnostic accuracy and comparability of thermography, triaxial dynamometry, and spinoscopy in the assessment of recent onset work-related low back pain. SUMMARY OF BACKGROUND DATA: The role of these technologies in assessing patients with low back pain is unproved. METHODS: Forty-one patients with low back pain and 46 control subjects were assessed by each technology and by two clinical examiners blind to clinical status. Twenty patients were trained to simulate a healthy back without low back pain, and 50% of the control subjects were trained to simulate the presence of a low back pain disorder. Each technology was interpreted on two occasions by each of two readers. RESULTS: Thermography performed significantly worse than did triaxial dynamometry, spinoscopy, and clinical examination. The diagnostic accuracy of the last three was similar, and inter-rater comparability did not differ significantly. Among simulators, the diagnostic accuracy of triaxial dynamometry and spinoscopy was significantly higher than that of clinical examination, although considerable inaccuracy remained in assessing individual subjects. CONCLUSIONS: The diagnostic accuracy of thermography in recent onset low back pain does not support its use. Among those simulating normality or low back pain, triaxial dynamometry and spinoscopy have greater diagnostic accuracy than does a single clinical evaluation. However, for an individual, the inaccuracy that remains limits the use of triaxial dynamometry or spinoscopy for diagnosis in recent onset low back pain.

Adult↗
PubMed1995

Variability of geometric measurements from three-dimensional reconstructions of scoliotic spines and rib cages.

Three-dimensional (3-D) reconstructions of the spine are being used with increasing frequency to describe scoliotic deformities, but the reproducibility of most of these techniques and the implication for the reliability of measurements made on the reconstructions has not been reported. How reliable are these reconstructions, and can a clinician interpret with confidence the results of studies based on such mathematical models? A reproducibility study of various computerised measurements obtained from 3-D reconstructions of the spine and rib cage for five subjects with adolescent idiopathic scoliosis was done to evaluate the errors associated with repeated measurements and compare them with inter- and intraobserver errors reported for similar commonly used clinical measurements. The mean variation for the Cobb angle differed according to the plane of computation from 0.6 degrees in the frontal plane to 6.7 degrees in the sagittal plane; vertebral axial rotation varied from 2.3 degrees to 5.9 degrees according to the vertebral level, and rib hump measurements displayed an average variation of 1.4 degrees. All these variations are below or within the error levels reported for equivalent 2-D measurements used by clinicians, which suggests that this 3-D model of idiopathic scoliosis may be used with confidence for clinical evaluations.

Child↗
PubMed1995

Reference values obtained by kernel-based estimation of quantile regressions.

In this paper, we study the problem of estimating non-parametrically a quantile regression curve as it applies to computing reference values. We propose an automatic procedure that uses a symmetrized nearest-neighbor kernel estimator of conditional distributions. We also discuss ways of measuring the dispersion of quantile regression estimator. One is based on the asymptotic distribution of such quantiles, while the other relies on the bootstrap method. The results of a small simulation study show that the methods of the paper perform rather well even in a situation where a good parametric solution is available. As an example, we analyze a small part of a data set that was collected to establish reference values for blood velocity in different parts of the umbilical cord of human fetuse as they grow toward birth.

Biometry↗
PubMed1994

Testing for inter-group contamination in a controlled longitudinal study of added physical education.

OBJECTIVE: This case report examines whether there was any cross-contamination between students enrolled in classes that received additional physical education, and their siblings who were enrolled in preceding and succeeding class-cohorts. EXPERIMENTAL DESIGN: A controlled longitudinal study extending over 6 years of primary school. SETTING: An urban and a rural primary school in Québec. PARTICIPANTS: 546 primary students, comprising approximately equal numbers of boys and girls from the urban and the rural school. INTERVENTION: Entire class-cohorts were given and hour of additional physical education ach day throughout their primary schooling, with immediately preceding and succeeding class-cohorts serving as controls. MEASURES: The measured data included standing height, body mass, maximal oxygen intake (direct treadmill test) and PWC170. RESULTS: We found no evidence of cross-contamination between siblings in experimental and control class-cohorts. CONCLUSION: Although a theoretical possibility, cross-contamination between students in preceding and succeeding class-cohorts does not seem an important source of error in primary school students, presumably because such children prefer to play with friends from their immediate age cohort.

Bias↗
PubMed1993

Relative contribution of physical activity to neonatal oxygen consumption.

To explore the relevance of distinguishing between resting and global energy expenditure in newborn infants, oxygen consumption (VO2) was measured during extremes of physical activity in 17 parenterally fed newborn infants with a large range of body weights (1.0-3.4 kg) and gestational ages (28-41 weeks). Under constant nutrient intakes, each infant served as his/her own control when comparing VO2 during resting conditions and spontaneous intense physical activity, called exercise. VO2 was significantly correlated with body weight at rest (r = 0.96). But during intense activity, the better predictor of exercise-induced VO2 was body weight in the smaller infants (< 2.0 kg) and gestational age in the larger infants (> 35 weeks). The difference in VO2 between both levels of activity represented the oxygen cost of exercise, which decreased (P < 0.01) with body weight. For clinical purposes, the physical activity of low-birth-weight infants does not contribute substantially to their energy balance.

Basal Metabolism↗
PubMed1993

Duplex Doppler sonographic examinations of the testis in prepubertal boys.

This retrospective study of 143 pediatric patients with unilateral acute scrotal disease was done to assess the value of duplex Doppler sonographic examination prior to puberty (110 patients) in comparison to a pubertal group (33 patients) in a pediatric hospital, where the examinations are done by staff radiologists and radiology residents of varying degrees of expertise and experience with Doppler technique. All patients seen during an 18 month period were included. The unaffected side was examined in most patients and served as control. The normal Doppler shift in the center of the prepubertal testis was found to be 0.2 to 0.5 kHz, when using a 5 MHz duplex Doppler probe. With puberty, the Doppler shift increased to 0.5 to 1 kHz. Of 18 patients (10 prepubertal) with testicular torsion, five (three prepubertal) had false-positive Doppler shift. In four of these five cases, faulty placement of the Doppler sample volume cursor was probably the cause. Using a multi-way frequency analysis, puberty was found to have no significant influence on results of Doppler signal (chi square = 0.1346; P = 0.7137). Duplex Doppler sonographic examination is as useful to rule out testicular torsion in prepubertal boys as it is after puberty. Meticulous technique is essential. The opposite side should be examined first and serves as control for the affected one. Results showing no flow in the center of the diseased testis with positive flow in the unaffected one should lead to further clinical action (scintigraphy or surgery).

Adolescent↗
PubMed1992

Stenosis of the renal artery: assessment of slowed systole in the downstream circulation with Doppler sonography.

Slowing and dampening of systole in the arterial network distal to stenosis is a well-known Doppler sign of severe arterial stenosis. To determine whether this sign is present in boys and girls with such stenosis, intrarenal Doppler curves (acceleration index [AI] and resistive index [RI]) were compared with findings on renal arteriograms in 20 boys and girls; the AI was also measured in 10 boys and girls without renal disease. Statistical analysis of AI and RI measurements was performed. Eleven of 32 renal arteries were normal. The normal AI was 4.0-7.0; in arteries with greater than 75% stenosis, the AI was 0.7-1.7. In five arteries studied after angioplasty, the AI had changed from 0.7-1.5 to 4.0-5.6 at the first posttreatment examination (performed 28 hours to 1 week after angioplasty), and it remained normal during the 3-year follow-up period. In kidneys with stenotic arteries, the RIs were lower (0.43-0.54) than in healthy subjects (0.56-0.63). Regression and correlation coefficients of AI and RI measurements were statistically significant, and discrimination between normal arteries and those with greater than 75% stenosis was excellent.

Child↗
PubMed1985

The "unisex phantom," sexual dimorphism, and proportional growth assessment.

The "unisex phantom" tactic of Ross and associates attempts to examine proportional growth, expressing body measurements relative to a phantom created from arbitrary mean dimensions and the observed coefficients of variation for an arbitrary sample of adult men and women. Fundamental assumptions of the model are (1) that data treated in unisex fashion have the normal distribution required of Z-type statistics throughout the period of growth, and (2) that it is reasonable to consider anthropometric measurements in all populations (regardless of ultimate size) as growing toward the common height chosen for the phantom. The validity and possible usefulness of this approach has been tested using anthropometric data collected on 546 francophone primary school children from the Trois Rivières district who had been measured repeatedly from 6 to 12 years of age. Over this age range, the mixing of data for girls and boys does not create a bimodal distribution, and has only a marginal effect upon skewing and kurtosis; however, the requirement of a normal distribution is not satisfied by quite a number of common anthropometric measurements even at this age. Moreover, application of the unisex phantom procedure to the Trois Rivières sample does little to clarify anticipated sex-related differences in regional growth, and it is argued that univariate standardization against a power function of an arbitrary adult height may not provide the best method of examining the multivariate problem of growth. Comparison of results with data from Saskatoon, previously treated by unisex phantom methodology, reveals puzzling inconsistencies; it is suggested that interlaboratory differences of methodology rather than ethnic differences are responsible for apparent discrepancies in growth patterns. It is urged that interlaboratory validation of techniques and landmarks should precede the ascription of apparent differences in body build to constitutional factors.

Anthropometry↗
PubMed1982

Role of midbrain raphe nuclei in stress-, pentobarbital-, beta-endorphin-, or TRH-induced changes in plasma PRL levels of adult male rats.

Radiofrequency lesions of either the dorsal (LD) or the median (LM) raphe nuclei of male rat mesencephalon did not modify baseline levels of plasma prolactin (PRL). However, the PRL releasing effect of 30 min of immobilization stress was suppressed in LM rats and enhanced in LD rats. The PRL releasing effect of pentobarbital (PB, 50 mg/kg, IP) or of beta-endorphin (END, 15 micrograms/rat, intracerebroventricularly, ICV) also was enhanced in LD rats. TRH (10 micrograms/rat, ICV) administered concomitantly with either PB or END, antagonized the releasing effect of the former and enhanced the releasing effect of the latter in sham operated rats. Lesions of the raphe nuclei blocked the antagonizing effect of TRH, while the enhancing effect was heightened in LD rats. These results indicate that neurons originating in the raphe nuclei are not involved in the control of baseline plasma PRL levels. They indicate, furthermore, the existence of an inhibitory pathway originating in the dorsal raphe nucleus the suppression or activation of which is, at least partly, the mechanism of PB, END or TRH effects on PRL release. The PRL releasing effect of immobilization stress seems to be under a dual, mutually antagonistic control: activating through the median and inhibitory through the dorsal nucleus.

Animals↗
PubMed1982

Beta blockers and their effects on lipoproteins, phospholipids, apoproteins A and B, in whole plasma and the different fractions.

Plasma levels of cholesterol (C), triglycerides (TG), phospholipids (PL) (in total plasma, very low density [VLDL], low density (LDL), and high density [HDL] lipoproteins) and of two apolipoproteins (apo-B and apo-A) were studied in 13 hyperlipidemic patients suffering from hypertension and/or stable angina and treated by metoprolol or propranolol. Propranolol reduced the low density and high density lipoprotein phospholipids by 26% and 11%, respectively, and increased the very low density phospholipids by 24%. Metoprolol had only a transient effect on high density lipoprotein phospholipids. VLDL apolipoprotein-B was markedly increased by propranolol (67%), whereas apolipoprotein-A was slightly (8%) increased during metoprolol treatment. The reduced low density lipoprotein phospholipids and the increased high density lipoprotein apo-A correlated with the plasma concentration of propranolol and metoprolol, respectively. These results suggest that the comparative effects of beta-adrenoreceptor blocking agents on lipoprotein metabolism should be considered in their long-term use in patients with risk factors for hypertension and myocardial infarction.

Adrenergic beta-Antagonists↗
PubMed1981

Circulating LH, FSH, prolactin, testosterone, delta 4-androstenedione, dehydroepiandrosterone sulfate and cortisol levels in the fetus in late gestation and in newborn male and female lambs.

Gonadotropins, prolactin (PRL), testosterone (T), delta 4-androstenedione, dehydroepiandrosterone sulfate and cortisol (F) levels were determined from 14 days before birth to term in 3 female and 3 male ovine fetuses with a chronically implanted venous catheter, and in the same animals from birth to 72 h of age. In both sexes, plasma gonadotropins and androgens were low throughout the period of study while plasma F increased with gestational age. After birth, plasma gonadotropins and PRL tended to increase progressively with time while PRL concentrations were significantly higher in female than in male lambs. F and T concentrations decreased significantly within the first 12 and 6 h of postnatal life. Higher T values were again observed at 36 h in male lambs. These data indicate that the fetal hypothalamic-pituitary-gonadal axis is relatively quiescent in the last 14 days of gestation but is activated within the first 72 h after birth.

Aging↗
PubMed1979

Further studies on the relationship of adrenal and gonadal steroids in pubertal development in female rats.

Surgical adrenalectomy or the administration of aminoglutethimide, corticosterone (B), and androstenedione (delta 4) to the immature female rat had no effect on the timing of vaginal membrane opening. Dehydroepiandrosterone (DHA) and estrone (E1) significantly hastened vaginal patency. Aminoglutethimide increased pituitary LH content while FSH content was decreased. An anti-17 beta-E2 antibody increased pituitary LH content and plasma concentration suggesting enhanced synthesis and release of LH. Pituitary FSH content was unaltered while plasma FSH decreased. Aminoglutethimide increased adrenal and ovarian but not pituitary weight while the antibody had no effect. Since little DHA is present in rat plasma and adrenal and since only estrogens have any effect on the onset of puberty, it is likely that the adrenal is not directly involved in pubertal development in the female rat.

Adrenal Glands↗
PubMed1979

[Bone maturity and physical performance].

We have examined the relation between physical performance (as measured with the CAHPER tests), bone age (Greulich and Pyl's wrist evaluation) and dental age (Garn's method). Our study included 164 boys and 149 girls aged from 7 to 11. In spite of interesting significant simple correlation between most of the CAHPER tests and bone age measurements for the pre-pubescent period, the latter remains of negligible value in predicting physical performance in the studied children when variables like chronological age, body height and body weight are already included in the prediction equation.

Age Determination by Skeleton↗