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Biomedical subjects

P Herkenrath

Publications and source records attributed to P Herkenrath.

10 recordsLinked to original sources
PubMed2002

[Transient neonatal myasthenia gravis].

Ten to twenty percent of the offspring of mothers suffering from myasthenia gravis (MG) also develop transient neonatal MG, since maternal antibodies are able to cross the placenta. We report the course of two newborns of a mother with MG and a healthy father. The first pregnancy was complicated during the 3rd trimester by a hydramnion. The newborn presented with generalized muscle weakness, respiratory distress, weak sounding, anaemia, and poor sucking. Mechanical ventilation was necessary. Confirmation of the diagnosis was achieved by the result of repetitive muscle stimulation, showing a typical decrement in the EMG, and measurement of serum antiacetylcholin receptor antibodies. For 3 months, the infant was treated with neostigmin (cholinesterase inhibitor). After 26 days of hospitalization, the patient was released and followed up regularly. Myasthenic symptoms completely resolved. Side effects of the treatment were not observed. The course of the second pregnancy was normal. This second newborn was healthy. Our case report is remarkable for the very different presentation of two children of the same mother with MG during pregnancy and after delivery, with one child developing severe transient neonatal MG, initially requiring intensive care unit (ICU) treatment followed by quick recovery, and one child being healthy. We also present a score for monitoring the clinical course and adjusting anticholinesterase therapy accordingly.

Adult↗
PubMed2001

Analysis of cancellous bone turnover by multiple slice analysis at distal radius: a study using peripheral quantitative computed tomography.

We compared the results of peripheral quantitative computed tomography (pQCT) measurements (XCT-900; Stratec) at the 4% site of the distal radius (section 1; slice thickness of 2 mm) and in two proximally adjacent sections (sections 2 and 3). The study population consisted of 138 ambulatory patients (age 16.4 +/- 5.6 yr; mean +/- SD; 71 female) who were referred to a pediatric densitometry unit. Total volumetric bone mineral density (BMD) increased, whereas the area of the radial cross-section decreased in a proximal direction. There was a decrease in bone mineral content between sections 1 and 3, which was more pronounced in subjects under age 16. Cancellous BMD significantly decreased from section 1 to 3 only under the age of 16. In 12 patients under age 17 who suffered from increased bone fragility, cancellous BMD decreased about 2.5 times more between sections 1 and 3 than in age-matched patients who received anticonvulsant therapy but had a normal neurologic and musculoskeletal status (-21.4% +/- 16.9 vs -8.1% +/- 6.3; p = 0.02). This suggests that in the bone fragility group, trabeculae were removed faster during longitudinal growth of the radius. In conclusion, multiple slice analysis may provide information on the dynamic turnover of metaphyseal trabeculae during growth.

Adolescent↗
PubMed2001

Analysis of the musculoskeletal system in children and adolescents receiving anticonvulsant monotherapy with valproic acid or carbamazepine.

OBJECTIVE: To examine bone development in children and adolescents who have uncomplicated idiopathic epilepsy and had received monotherapy with carbamazepine or valproic acid for at least 1 year. METHODS: Thirty-nine patients from 6 to 19 years of age (18 girls) were studied. Total bone mineral content (BMC) and trabecular volumetric bone mineral density were measured at the distal radius using peripheral quantitative computed tomography. Maximum isometric grip force was determined with a standard dynamometer. Alkaline phosphatase activity and deoxypyridinoline (a marker of bone resorption) were assessed in serum and urine, respectively. RESULTS: Trabecular volumetric bone mineral density was significantly decreased in the entire group (z score mean +/- standard deviation: -0.62 +/- 1.04) and in the subgroup using valproic acid (-0.75 +/- 1.18). In the carbamazepine subgroup, there was a similar but nonsignificant trend (-0.50 +/- 0.90). Total BMC and isometric maximum grip force were normal in the entire study population (0.10 +/- 1.22) and in the 2 subgroups. The relationship between BMC and grip force was similar between patients and healthy participants. Urinary levels of deoxypyridinoline were significantly elevated above normal in the whole study population (1.35 +/- 2.00) and in both the valproic acid and the carbamazepine subgroups. CONCLUSIONS: Bone turnover can be increased, but bone mass is adequate in children and adolescents who have uncomplicated idiopathic epilepsy and who receive monotherapy with carbamazepine or valproic acid.

Adolescent↗
PubMed1999

Right sternoclavicular dislocation after traumatic delivery: a case report.

Sternoclavicular (SC) dislocation is an injury that is very rare in the newborn. Thus far there have been no reports describing this in neonates after a traumatic birth injury. This condition can be difficult to differentiate from epiphyseal separation, which occurs more often in older children. For successful treatment, early diagnosis is essential. Timely surgical reposition and fixation with following immobilization is recommended in instances of complete (SC) dislocation. We report a trauma-induced case of SC dislocation in a neonate successfully managed by polydioxanon cord fixation.

Birth Injuries↗
PubMed1997

Cerebral complications in Schimke immuno-osseous dysplasia.

UNLABELLED: Schimke immuno-osseous dysplasia is a multisystem disorder consisting of spondylo-epiphysial dysplasia, progressive renal insufficiency due to focal segmental glomerulosclerosis, and immunodeficiency. Cerebrovascular complications have only been described in five patients. Here we report a patient with prominent neurological symptoms most likely caused by transient ischaemic attacks. CONCLUSION: Neurological symptoms consisted of repeated brief spells of hemiparaesthesia, motoric aphasia and diplopia. MRI studies of the CNS revealed progressive white matter lesions. Morphological changes as well as neurological deficits are compatible with cerebral ischaemia.

Brain↗
PubMed1988

Di-(2-ethylhexyl)-phthalate as plasticizer in PVC respiratory tubing systems: indications of hazardous effects on pulmonary function in mechanically ventilated, preterm infants.

Several PVC medical devices contain the plasticizer Di-(2-ethylhexyl)-phthalate (DEHP) in high concentration. Taken systematically DEHP only has minor toxic effects in the human organism. In three preterm infants artificially ventilated with PVC respiratory tubes unusual lung disorders resembling those observed in hyaline membrane disease, verified both clinically and radiologically, were observed during the fourth week of life. It was assumed that these lung disorders were causally related to the exposure to high doses of DEHP, which was released from the walls of the respiratory tubes. DEHP was found in the lung tissue of one patient who died of pneumothorax soon after birth after being artificially ventilated. It is strongly recommended that for disposable PVC respiratory devices the plasticizer DEHP should be used with more restrictions.

Diethylhexyl Phthalate↗
PubMed1986

Nifedipine in hypertensive crises of infants and children.

Nifedipine given by the sublingual route has been used in the treatment of 30 hypertensive emergencies in 20 children suffering from renal disease. The mean dosage of nifedipine was 0.33 mg/kg body weight. In 20 hypertensive crises occurring in 16 patients a single dose of nifedipine was sufficient to lower systolic as well as diastolic blood pressure significantly within 90 min. for a period of 4 to 12 hours. No side effects were noted with the exception of a transient flush in one patient. Nifedipine proved to be suitable for the primary treatment of hypertensive emergencies in children suffering from renal hypertension. The advantages of nifedipine compared to other drugs used for treating hypertensive crises is the rapid onset of the antihypertensive action without need for an intravenous form of administration.

Adolescent↗
PubMed1984

The kinetics of hematopoietic stem cells during and after hypoxia. A model analysis.

A previously described mathematical model of the hematopoietic stem cell system has been extended to permit a detailed understanding of the data during and after hypoxia. The model includes stem cells, erythroid and granuloid progenitors and precursors. Concerning the intramedullary feedback mechanisms two basic assumptions are made: 1) The fraction "a" of CFU-S in active cell cycle is regulated. Reduced cell densities of CFU-S, progenitors or precursors lead to an accelerated stem cell cycling. Enlarged cell densities suppress cycling. 2) The self renewal probability "p" of CFU-S is also regulated. The normal steady state is described by p = 0.5, indicating that on statistical average each dividing mother stem cell is replaced by one daughter stem cell, while the second differentiates. Diminished cell densities of CFU-S or enlarged densities of progenitors and precursors induce a more intensive self renewal (p greater than 0.5), such that the stem cell number increases. The self renewal probability declines (p less than 0.5) if too many CFU-S or too few progenitors and precursors are present. The model reproduces bone marrow data for CFU-S, BFU-E, CFU-C, CFU-E, 59 Fe-uptake and nucleated cells in hypoxia and posthypoxia. Although the ratio of differentiation into the erythroid and granuloid cell lines is kept constant in the model, a changing ratio of CFU-E and CFU-C results. The model suggests that stem cells and progenitor cells are regulated by a regulatory interference of erythropoiesis and granulopoiesis.

Cell Differentiation↗
PubMed1983

[Mathematical models in hematology].

The use of mathematical models in haematology is shown by some examples concerning stem cell kinetics, erythropoiesis and thrombopoiesis. At first, model assumptions are formulated which include the biological knowledge and some regulatory hypotheses. Then, the reaction of the model on stimulation and suppression is calculated. Finally, by comparison with experimental or clinical data one can evaluate how far the model assumptions are sufficient to understand the measurements. Thus one can exclude wrong hypotheses and identify the important regulatory influences.

Blood Platelets↗