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Biomedical subjects

G Theintz

Publications and source records attributed to G Theintz.

28 records · Page 2Linked to original sources
PubMed1991

Critical years and stages of puberty for spinal and femoral bone mass accumulation during adolescence.

Maximizing peak bone mass is advocated as a way to prevent osteoporosis. As a prerequisite to the elaboration of any preventive program aimed at maximizing peak bone mass, it is important to determine how the rate of skeletal growth at clinically relevant sites, such as lumbar spine and femoral neck, proceeds in relation to age and pubertal stages in both sexes. Bone mass was assessed in 207 healthy caucasian boys and girls, aged 9-18 yr. Bone mineral density (BMD; grams per cm2) and content (BMC; grams) were determined in lumbar spine (L2-L4), femoral neck (FN), and midfemoral shaft (FS), using dual energy x-ray absorptiometry. Bone variables were correlated with both chronological age and pubertal stage, and compared with young adult (20-35 yr) reference values. The main results are: 1) in males, compared to females, there was a marked age-related delay in L2-L4 BMD or BMC increase, but no delay was observed in relation to pubertal stages; 2) at the end of the rapid growth spurt, trends for higher mean values in males were observed for L2-L4 BMC, FN BMD, and particularly FS BMD, but no sex difference was observed for L2-L4 BMD; 3) in females, but not in males, a dramatic reduction in bone mass growth was observed after 15 yr of age, particularly for L2-L4 BMD/BMC and FN BMD. This sharp reduction occurred between the second and fourth years after menarche. In the 14- to 15-yr-old female group, BMD in L2-L4, FN, and FS corresponded to 99.2%, 105.1%, and 94.1%, respectively, and BMC in L2-L4 to 97.6% of the mean values recorded in 20- to 35-yr-old women. In conclusion, this cross-sectional study indicates that during pubertal development, major differences are observed in bone mass growth according to sex and skeletal site. Whereas in males bone mass at different skeletal sites continues to increase substantially between 15-18 yr, skeletal mass growth appears to dramatically slow down at the levels of both lumbar spine and FN at 15-16 yr of age in female adolescents. This suggests that the generally accepted notion that in both males and females bone mass continues to substantially accumulate at all skeletal sites until the fourth decade may not be a constant in human physiology.

Absorptiometry, Photon↗
PubMed1990

[Semiautomatic insulin injection equipment (pens)].

To the best of our knowledge, a good glycaemic control must be advised to avoid or delay the degenerative complications of diabetes, bearing in mind an increased risk of hypoglycaemias. Among other techniques, a treatment consisting of multiple injections (basal-bolus concept) is one way to achieve a good control. Although this form of treatment is rather restrictive (frequent blood glucose determinations), the use of pens makes it more acceptable. A fully informed and cooperative patient is a prerequisite before considering this particular type of insulin therapy which, however, is usually not very helpful for older diabetics. It is a misconception to think that every patient receiving insulin should do so with a pen, just as it is incorrect to recommend multiple injections for all type I diabetics. Whether such a therapeutic strategy is indicated should be established for each patient individually. In addition, the fashion for pens should not distract us from all the other problems associated with inadequate diabetic control, such as foot care and systematic blood pressure measurements.

Diabetes Mellitus, Type 1↗
PubMed1989

Growth in a case of Russell-Silver syndrome treated for hypopituitarism.

The growth characteristics of Russell-Silver syndrome (RSS) include dwarfism of prenatal onset, moderate retardation of bone age and normal postnatal height velocity. We describe a case of hypopituitarism in a girl with typical RSS who suffered from a severe trauma at birth. Signs of hypopituitarism appeared during childhood. Before substitutive treatment, a short course of human growth hormone (hGH) induced a moderate rise in plasma IGF-I levels which was within the range observed in other pituitary dwarfs. Under replacement therapy, catch-up growth was similar to what is observed in other growth hormone deficient children. However, bone age matured much faster than chronological age. This observation appears to be a particular feature of RSS, possibly enhanced by hGH therapy. An improvement of adult height beyond the final height usually observed in RSS children without endocrine disturbances should therefore not be expected from hGH therapy. Growth hormone deficiency and RSS do not appear to be causally related. However, in each child with RSS, a particular attention should be given to a decreased height velocity, a severely delayed bone age as well as a history of major perinatal problems. Should one of these factors be found, a careful evaluation of the hypothalamo-pituitary axis ought to be performed with, accordingly, an appropriate substitutive therapy.

Child↗
PubMed1989

[The coach of artistic gymnastics facing medical problems: results of a survey conducted in French-speaking Switzerland].

The need for high technical skills in gymnastics has resulted in a decrease of the age of talented gymnasts. Young gymnasts are submitted to intensive training, hence to an increase of the risk of injuries. In spite of this evolution, present medical assistance does not appear to be readily accessible to swiss coaches and gymnasts. By necessity, coaches endorse medical functions which have so far not been evaluated. This aspect was therefore investigated among coaches from the french speaking community of our country. The results show that the present medical network hinders regular follow-up of gymnasts and valuable discussions between coaches and doctors with, as a result, inappropriate medical teaching. Coaches distrust advice given by doctors of whom most underestimate the technical aspects of this sport. Medical assistance should be improved on a regional basis.

Adolescent↗
PubMed1987

Lack of bromocriptine-induced reduction of predicted height in tall adolescents.

Fifteen girls and five boys with excessive predicted adult height (chronological age, 10.1-14.6 yr; bone age, 11.0-14.0 yr) were treated with bromocriptine (two doses; 2.5 mg/day) to reduce their final height. After a mean treatment period of 1.14 yr (range, 0.6-1.75 yr) we did not find a reduction of predicted adult height [difference, -0.5 +/- 3.5 (+/- SD) cm according to Bayley and Pinneau's tables (P = NS) and +0.2 +/- 2.5 (+/- SD) cm according to the method of Tanner (P = NS)]. Mean peak plasma GH concentrations after TRH administration before and during bromocriptine were 51.5 +/- 49.4 and 58.5 +/- 50.7 mU/L, respectively. The wide range of the GH values may be explained by physiological variation in this age group. After ingestion of 2.5 mg bromocriptine a significant increase in plasma GH occurred within 3 h in six adolescents tested. Our results do not support the concept that bromocriptine may reduce predicted adult height in tall adolescents by decreased GH secretion or acceleration of skeletal maturation.

Adolescent↗
PubMed1986

Nocturnal urinary melatonin excretion and plasma cortisol levels in children and adolescents after a single oral dose of dexamethasone.

In the present study, the possible relationship between melatonin secretion as reflected by nocturnal melatonin excretion (2000 h-0800 h) and the pituitary-adrenocortical axis was investigated. Nocturnal urinary melatonin excretion and plasma cortisol levels were determined in 41 children with weight problems before and after a single oral dose of dexamethasone. A first group of 15 individuals with normal cortisol cycle (12.2 +/- 1.4 at 0800 h and 3.1 +/- 0.5 micrograms/100 ml at 1700 h), and levels below 1.0 microgram/100 ml after dexamethasone, showed a highly significant increase in melatonin excretion during the night following dexamethasone treatment (63.5 +/- 5.5 ng/12 h vs 33.6 +/- 3.0 for the control night, P less than 0.001). This increase was observed from prepuberty to young adulthood (pubertal stages PI-PV). In a second group of 16 subjects with mean cortisol levels similar at 0800 h and 1700 h (10.7 +/- 1.3 and 9.3 +/- 1.5 micrograms/100 ml respectively), but with a normal cortisol suppression after dexamethasone administration, nocturnal melatonin excretion increased from 21.2 +/- 2.1 to 33.4 +/- 3.0 ng/12 h (P less than 0.01). A significant increase was found in prepubertal children (PI) whereas no change was observed at the end of pubertal development (stages PIV-PV). A third group of 10 patients with both low amplitude cortisol cycles (16.2 +/- 2.5 and 10.8 +/- 2.4 micrograms/100 ml) and abnormal cortisol suppression after dexamethasone administration (9.1 +/- 2.4 micrograms/100 ml), showed no increase in melatonin excretion (24.2 +/- 2.7 and 24.9 +/- 3.7 ng/12 h).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1982

A fourth case of ring chromosome 7.

An 8-year-old child with a ring chromosome 7 is presented, the first female and the fourth such individual to be described. The associated anomalies were rather benign: she presented with short stature, minor skeletal alterations, and normal intelligence. The only truly striking feature was the presence of multiple large, pigmented naevi, suggestive of a hamartomatous origin, but unlike those typical of any particular syndrome. Though other ring 7 patients have had naevus flammeus, and one had café-au-lait spots, our proband is the first with an anomaly of chromosome 7 to have such extensive lesions. These four cases of ring 7, which show great phenotypic variation, are reviewed, and the clinical presentation of the proband is also compared with that of patients suffering from terminal, interstitial and translocation-derived 7p and 7q deletions. The formation and behavior of ring chromosomes are discussed, as are the cytogenetic factors which may influence their phenotypic expression.

Child↗
PubMed1982

Growth and pubertal development in five boys with Noonan's syndrome.

Five boys, each with at least 4 features characteristic of Noonan's syndrome, were studied throughout childhood. In each the height was on or below the 3rd centile. Height velocity was essentially normal during the prepubertal period whereas bone age and pubertal development were delayed. Four boys had cryptorchidism and in 2 no testicular enlargement or spontaneous puberty occurred, necessitating testosterone replacement. Plasma concentrations of luteinising hormone and follicle-stimulating hormone before and after stimulation with luteinising hormone-releasing hormone were increased in 4 of the boys. These findings are consistent with primary gonadal failure associated with impaired spermatogenesis.

Adolescent↗
PubMed1981

Gonadotrophin response to LH-RH in boys with delayed growth and adolescence.

Plasma luteinising hormone (LH) and follicle-stimulating hormone (FSH) concentrations were measured before and after intravenous luteinising hormone-releasing hormone (LH-RH) in 33 boys with growth delay. Eighteen were prepubertal and 15 pubertal. Basal LH and FSH levels were low in both groups with mean increments after LH-RH of 3.2 +/- 0.8 U/l (mean +/- SEM) and 2.6 +/- 0.4 U/l respectively in the prepubertal and 7.4 +/- 0.7 U/l and 2.0 +/- 0.3 U/l in the pubertal boys. The LH increment showed a positive correlation with increasing bone age (r = 0.71, P less than 0.001); FSH did not. The LH-RH response thus appeared normal in relation to the stage of maturity.

Adolescent↗