Biomedical subjects

R Feneberg

Publications and source records attributed to R Feneberg.

7 recordsLinked to original sources

PubMed2001

Exercise induced hypoglycaemic hyperinsulinism.

BACKGROUND: Hyperinsulinism in childhood is often caused by genetic defects involving the regulation of insulin secretion leading to recurrent episodes of hypoglycaemia. We report two patients with exercise induced hypoglycaemia. METHODS: Standardised short exercise tests with frequent blood glucose and plasma insulin measurements were performed in the patients and young healthy controls. RESULTS: Short term exercise resulted in insulin induced hypoglycaemia 15 to 50 minutes after the end of exercise. A massive burst of insulin secretion was observed within a few minutes of the start of exercise in both patients. By contrast glucose and insulin concentrations remained unchanged in healthy controls. CONCLUSIONS: Hyperinsulinaemic hypoglycaemia after moderate physical exercise represents a rarely described phenotype of hyperinsulinism with an as yet unknown defect in the regulation of insulin secretion. It should be suspected in individuals with recurrent exercise related syncope or disturbance of consciousness.

Adolescent↗

PubMed2000

Assessment of body composition in children with chronic renal failure.

In children with chronic renal failure treated conservatively by dialysis or by transplantation, various alterations of the nutritional, metabolic and fluid homeostasis may occur that may critically affect the patients' acute and chronic well-being. In the past, the assessment of body composition in children was hampered by insufficient precision, standardization and/or availability of appropriate anthropometric tools. Recently, there have been several methodological advances that may facilitate close and precise monitoring of body composition in this population. Specifically, the use of body mass index (BMI) data in children has become possible by the introduction of pediatric reference values processed for the calculation of standard deviation scores accounting for the skewed distribution of BMI. Skewness-adapted reference data have also been provided for percentage fat mass as assessed by multisite skinfold measurements. In addition, bioelectrical impedance analysis has been validated in healthy children as well as in pediatric dialysis and renal transplant populations. This novel auxological technique provides a highly reproducible, non-invasive and inexpensive way of assessing changes in total body water content in dialysed patients, as well as changes in fat and fat-free mass prior to dialysis and after renal transplantation.

Body Composition↗

PubMed2000

Experience with deflazacort in children and adolescents after renal transplantation.

Deflazacort (DFZ) has been proposed as an alternative drug for immunosuppression after renal transplantation (TX), with fewer side effects than conventional glucocorticoids. We investigated renal function, body growth, body fat, and bone mineral density (BMD) after switching from oral methylprednisolone (MPR) to equivalent doses of DFZ 1-9 years after TX in 20 patients aged 5-20 years, selected because of severe adverse effects from previous steroid therapy. At conversion the patients received a mean dose of 7.4 +/- 2.4 mg DFZ/m2 per day. The drug was continued for a mean of 3.7 (1.2-5.5) years. Under DFZ, the glomerular filtration rate dropped slightly (NS). A single rejection episode occurred. Growth velocity significantly improved in the 1st year on DFZ treatment and height standard deviation score (SDS) increased steadily after introduction of DFZ (from -2.64 to -1.96 after 4 years, P = 0.06). However, in 10 prepubertal children the height gain (+0.20 SDS in 2 years on DFZ) was not significant and the overall mean annual growth rate after TX was similar to that in 10 matched prepubertal TX children on continued MPR treatment. Relative obesity, estimated from mean body mass index corrected for height, was reduced from +1.11 SDS at the start of DFZ to +0.71 SDS after 2 years (P = 0.03) and to +0.39 SDS after 4 years (NS). BMD-SDS of the lumbar spine (L2-4) increased after 1 year on DFZ (P = 0.005). In conclusion, DFZ is well tolerated and safe in pediatric patients after TX. It improves relative obesity and bone mineralization. However, body growth is not significantly influenced pre puberty.

Adipose Tissue↗

PubMed1999

Synchronous fluctuations of blood insulin and lactate concentrations in humans.

Oscillatory organization is a universal mode of signal transduction in living organisms. In vitro studies suggest spontaneous pulsatile fluctuations of intracellular energy metabolism. It is possible that, in vivo, some of these processes are synchronized by the pulsatile release of insulin. We assessed a potential coupling among plasma insulin, glucose, and lactate concentrations, by frequent blood sampling for 24 h in 11 healthy volunteers. Insulin sensitivity was assessed using the euglycemic hyperinsulinemic clamp technique. Lactate concentrations exhibited pulsatile fluctuations at an average interval of 84 +/- 11 min, whereas sodium and pH were nonpulsatile. The lactate concentration pulses closely corresponded to insulin oscillations, which occurred with a periodicity of 86 +/- 11 min. Blood glucose also fluctuated during daytime at an interval of 89 +/- 32 min. During nighttime, the frequency and amplitude of glucose oscillations were lower. The daytime profiles showed significant temporal coupling and pattern synchrony among insulin, lactate, and glucose. Only the close temporal relationship between insulin and lactate release persisted during nighttime. The temporal coupling and pattern synchrony between insulin and lactate were correlated inversely with insulin sensitivity, and positively with the degree of abdominal obesity. Our results suggest that: 1) the concentration of lactate, an indicator of cellular energy metabolism, fluctuates periodically in vivo; 2) the lactate concentrations fluctuate in synchrony with insulin pulses; and 3) such coupling is more pronounced in obese, insulin-resistant individuals.

Adult↗

PubMed1998

Percutaneous renal biopsy in children: a 27-year experience.

BACKGROUND: The introduction of automated biopsy devices and the localization of the kidney by ultrasound were aimed at optimizing efficacy and safety of the percutaneous renal biopsy procedure. We evaluated these technological advances in our renal biopsies performed in children. METHODS: We sequentially used the Silverman needle (1969-1974), the TruCut needle (1974-1990), and the automated Biopty device (1990-1996). Fluoroscopy was used to localize the kidney until 1985, ultrasound examination prior to biopsy from 1985 to 1992, and direct ultrasound guidance since 1992. A total of 962 native kidney biopsies and 119 allograft biopsies were performed. RESULTS: In the native kidney biopsies, the introduction of the Biopty device and ultrasound guidance were independently associated with fewer passes required to obtain adequate tissue and more glomeruli per specimen. The rate of biopsies yielding more than 9 glomeruli increased from 69 to 92% (p < 0.05). The number of glomeruli harvested per centimeter core length was inversely related to patient age (p < 0.01). More appropriate cortical tissue was retrieved in renal allograft biopsy specimens with the application of the new techniques. The occurrence of macroscopic hematuria (9. 6%) in the native kidney biopsies was not affected by the puncture or localization technique applied, but subcapsular hematomas were documented more often with the Biopty device (42%) than with the TruCut needle (16%), probably due to improved ultrasound equipment. In the whole series 2 patients died, and 3 others required renal surgery and 4 blood transfusions. CONCLUSIONS: The automated ultrasound-guided procedure is a feasible and reliable technique for percutaneous renal biopsy in children. It gives a greater yield of diagnostic tissue without increasing the rate of clinical complications.

Adolescent↗

PubMed1997

Abnormal pulsatile secretion of growth hormone in non-insulin-dependent diabetes mellitus.

OBJECTIVE: Studies of GH secretion in patients with non-insulin dependent diabetes mellitus (NIDDM) have produced conflicting results. We aimed to differentiate the effects of obesity and metabolic control on pulsatile GH secretion in patients with NIDDM. DESIGN: Blood sampling every 15 min from 22.00 hours to 08.00 hours after a fasting period of at least 3 h. PATIENTS: 13 male NIDDM patients, 9 healthy control subjects matched for age and BMI, and 6 lean subjects matched for age. MEASUREMENTS: Measurement of GH by a novel ultrasensitive chemiluminescence assay. Analysis of concentration vs time profiles by a multiparameter deconvolution technique. RESULTS: GH burst frequency was increased in the NIDDM (0.82 +/- 0.28 h-1) compared with both control groups (lean: 0.6 +/- 0.11; obese: 0.56 +/- 0.19). GH burst mass was decreased in patients (1.57 +/- 0.98 micrograms/l.min) and in obese controls (1.46 +/- 1.44) compared to lean controls (3.71 +/- 3.88). These differences resulted in a significantly higher nocturnal pulsatile GH secretion rate in the lean compared to the obese controls, whereas in the patient group enhanced GH burst frequency compensated for reduced burst mass. The characteristics of GH secretion were not related to nocturnal or early morning blood glucose concentrations. However, GH secretion rate was correlated positively with HbA1c (r = 0.57; P = 0.04), and negatively with plasma C peptide concentrations. CONCLUSIONS: The specific increase in GH burst frequency previously described in insulin-dependent diabetes mellitus is also present in NIDDM. However, GH hypersecretion does not occur because GH burst mass is reduced in proportion to the degree of obesity. The effect of diabetes on the hypothalamic control of GH release appears to be determined by the quality of long-term glycaemic control.

Analysis of Variance↗

PubMed1994

Papillary squamous neoplasms of the head and neck.

Papillary squamous neoplasms of the upper respiratory tract are rare variants of squamous cell carcinoma and are related temporally to proliferative verrucous leukoplakia. Fifty-two cases of papillary squamous neoplasms were selected from 2366 cases of squamous cell carcinoma. This is the first study to characterize the biological behavior of papillary squamous neoplasms. Papillary squamous neoplasms exhibit two distinct, yet sometimes overlapping, histologic patterns including an exophytic papillary and an inverting verrucous morphologic appearance. A high rate of synchronous or metachronous lesions were found, especially with the inverting-type of papillary squamous neoplasm. Stage T3 and T4 lesions had a high rate of neck metastasis. Early surgical intervention and close long-term follow-up is mandatory.

Adult↗