Biomedical subjects

H Siemes

Publications and source records attributed to H Siemes.

60 records · Page 4Linked to original sources

PubMedDate not supplied

Increased concentration of prostaglandin E-2 in cerebrospinal fluid of children with febrile convulsions.

Concentrations of prostaglandins (PGs) in the central nervous system are known to increase during and after experimentally induced seizures. In the present study, concentrations of PGE-2 were determined by radioimmunoassay in lumbar cerebrospinal fluid (CSF) of 17 children shortly after a febrile convulsion. PGE-2 data of these children were compared with those determined in afebrile children and febrile children without convulsions. Duration of storage of CSF samples at -30 degrees C prior to analysis had no influence on PGE-2 levels. Compared with afebrile patients, PGE-2 levels were significantly higher after febrile convulsions. Significantly elevated concentrations of PGE-2 were also found in febrile children without seizures, although the mean PGE-2 level in these patients was somewhat lower than that determined after a febrile convulsion. When body temperature of the patients was compared with their CSF PGE-2 levels, a significant positive correlation was determined between both variables. It is therefore not clear if the increased concentrations of PGE-2 in CSF of patients with febrile convulsions are, at least in part, to be related to increased PG synthesis and release during and after the seizure or are solely to be related to the febrile state of the children.

Child↗

PubMedDate not supplied

Penetration of valproate and its active metabolites into cerebrospinal fluid of children with epilepsy.

Levels of the antiepileptic drug valproate (VPA) and five of its active metabolites (2-en-VPA, 3-keto-VPA, and 3-,4-, and 5-hydroxy-VPA) were determined by gas chromatography-mass spectrometry in cerebrospinal fluid (CSF) of 15 epileptic children undergoing chronic treatment with VPA. In eight of these children, total and free drug and metabolite concentrations in plasma were also measured. All VPA metabolites present in plasma could also be detected in CSF, although concentrations were substantially lower than those of the parent compound. CSF concentrations of VPA and most of its metabolites were positively correlated with total and free concentrations in plasma. However, concentrations in CSF were always significantly lower than free plasma concentrations, which may be explained by asymmetric transport at the blood-CSF barrier. The data on low CSF levels of VPA metabolites do not exclude the possibility that accumulation of active metabolite(s) may occur in certain brain areas during chronic treatment of epileptic patients with VPA.

Child↗

PubMedDate not supplied

Therapy of infantile spasms with valproate: results of a prospective study.

In a prospective study, 22 children with recently manifested infantile spasms (18 patients with symptomatic and 4 with idiopathic infantile spasms) were treated with sodium valproate (VPA). Before VPA was instituted, a loading test was performed to exclude abnormal patterns of VPA metabolites by gas chromatography and mass spectroscopy of serum and urine. This test was repeated during VPA therapy; an abnormal pattern of VPA metabolites was not observed. VPA was started in increasing dosage until infantile spasms were controlled or a maximum dose of 100 mg/kg/day was reached. If VPA did not control seizures or at least reduce frequency significantly after a trial of 4-6 weeks, dexamathasone was added to VPA. If focal seizures occurred in association with localized epileptogenic EEG discharges, carbamazepine (CBZ) was added to VPA. After 4 weeks of VPA monotherapy, infantile spasms were controlled in 11 children. After 3 months of therapy, 16 children were free of seizures (14 patients VPA monotherapy), and 4 children had reduction of seizure frequency to less than 25%. VPA doses varied between 40 and 100 mg/kg/day (mean 74). The mean plasma concentration was 113 micrograms/ml (range 46-177). After 6 months of therapy, total seizure control was achieved in 20 of 22 patients (16 children VPA monotherapy). The mean observation time was 16 1/2 months (range 6-36 months). There were seven relapses in six children during the first 7 months of therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Valproate metabolites in serum and urine during antiepileptic therapy in children with infantile spasms: abnormal metabolite pattern associated with reversible hepatotoxicity.

The purpose of this study was to identify abnormal metabolite patterns of valproate (VPA) as possible early indicators of VPA-induced liver toxicity. In a prospective study, we determined serum and urine levels of VPA metabolites by gas chromatography-mass spectrometry (GC-MS) during the course of therapy in 25 children treated for infantile spasms with high VPA doses (less than or equal to 100 mg/kg body weight/day). Most patients had similar metabolite profiles: The main metabolites in serum were the beta-oxidation products (2-en-VPA and 3-keto-VPA) and the major diunsaturated metabolite 2,3'-dien-VPA. Glucuronide conjugates and the oxidation products represent the most abundant metabolites in urine. Other metabolites, including the potential hepatotoxin 4-en-VPA, were detected only in low concentrations. Two children had transiently aberrant metabolite profiles, indicating altered beta-oxidation, (levels of 2-en-VPA, 2,3'-dien-VPA, and 3-en-VPA were markedly increased) in connection with hepatomegaly and increased liver enzyme activities at a time when both had febrile infections and were receiving dexamethasone comedication. At no time were increased levels of 4-en-VPA or its derivatives detected. Establishing the VPA metabolite profile may aid in evaluation of patients who show signs and symptoms of liver dysfunction during VPA therapy. The present study shows that initial stages of hepatotoxicity reactions to VPA may be accompanied by characteristic changes in VPA metabolism; early detection of such abnormal metabolite patterns might decrease the risk of severe hepatic injury.

Chemical and Drug Induced Liver Injury↗

PubMedDate not supplied

Valproate (VPA) metabolites in various clinical conditions of probable VPA-associated hepatotoxicity.

Of a cohort of 470 epileptic patients in whom valproate (VPA) serum metabolites had been measured, 170 subjects without symptoms or signs of hepatic side effects were chosen as a reference group to establish the usual metabolic pattern. A wide interindividual variation of VPA metabolite concentrations was noted. Infants receiving VPA monotherapy and comedication with other antiepileptic drugs (AEDs) showed lower concentrations of the potential hepatotoxin 4-ene-VPA than did older children. In 11 patients with early symptoms and signs of possible fatal VPA-associated hepatotoxicity, the following spectrum of benign clinical conditions was observed: unusually severe side effect during initiation of VPA therapy (1 patient), high VPA dosage (2 patients), reversible impairment of coagulation with bleeding manifestations in association with a slight increase in transaminase levels (1 child), and reversible liver dysfunction associated with febrile illness (7 patients). Reversible or irreversible fulminant liver failure had occurred in 5 children. Three of the 4 children with a fatal outcome had massive lactic acidosis. In all patients with probable VPA-associated hepatotoxicity, some aspects of VPA metabolism differed distinctly from that of the reference group, but the inter-individual profile of metabolites varied considerably, even in the subgroup of 4 children who died. Impairment of VPA beta-oxidation and increase of metabolites of alternative metabolic pathways (omega- and omega 1-hydroxylation, dehydrogenation reactions) were the most frequent findings. Increased values of 2-n-propyl-4-pentenoic acid metabolite of VPA (4-ene-VPA), could be detected only in 1 of the 5 patients with fulminant liver failure and in one other child with a slight hepatic dysfunction, indicating that this VPA metabolite is not the decisive hepatotoxin or indicator of hepatotoxicity. Because we cannot distinguish between benign and life-threatening hepatic adverse reactions on the basis of VPA metabolites, all identified changes are considered secondary to an as-yet-unknown primary metabolic event. The most toxic compound could be VPA itself, which may unmask an inborn or an acquired metabolic defect in the processing of fatty acids.

Chemical and Drug Induced Liver Injury↗

PubMedDate not supplied

Severe hepatotoxicity during valproate therapy: an update and report of eight new fatalities.

Since our last report on valproate (VPA)-related hepatotoxicity in 1988, 8 other children have died of VPA-associated liver failure in Germany and Switzerland. We compared the clinical course of these children with that of 6 children with a reversible outcome of severe hepatotoxicity related to VPA. Thirty-five percent of patients with fatal liver failure were normally developed, 23.5% were receiving VPA monotherapy, and 35.3% were aged < or = 2 years. The initial clinical symptoms of VPA-related hepatotoxicity were nausea, vomiting, apathy or coma, and increasing seizures in more than 50% of patients, in combination with febrile infections at onset of symptoms. As compared with the series of German patients reported in 1988, one third of the fatalities occurred after the first 6 months of therapy as compared with 6% in the 1988 series. Clinical symptoms and laboratory findings were the same in patients with reversible and with fatal outcome. Early or immediate withdrawal of VPA after the first signs of VPA-associated hepatotoxicity may be responsible for the increased number of children who recovered after VPA-related severe liver failure. The pathogenesis of liver failure during VPA treatment remains unknown; metabolic defects and cofactors such as polypharmacy or infections have become increasingly likely to contribute by depleting intracellular CoA. Worldwide, 132 patients have died of VPA-associated liver failure and/or pancreatitis. Because a group at risk for fatalities with VPA cannot be defined precisely, patients treated with VPA and their families must be made well aware of the clinical symptoms of hepatotoxicity such as apathy, vomiting, or increased seizure frequency, especially in the presence of febrile infections. Laboratory tests and clinical controls during the first 6 months of therapy should not be neglected.

Adult↗