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Biomedical subjects

Jutta Gärtner

Publications and source records attributed to Jutta Gärtner.

At least 19 recordsLinked to original sources
PubMed2007

Breathing dysfunctions associated with impaired control of postinspiratory activity in Mecp2-/y knockout mice.

Rett syndrome (RTT) is an inborn neurodevelopmental disorder caused by mutations in the X-linked methyl-CpG binding protein 2 gene (MECP2). Besides mental retardation, most patients suffer from potentially life-threatening breathing arrhythmia. To study its pathophysiology, we performed comparative analyses of the breathing phenotype of Mecp2-/y knockout (KO) and C57BL/6J wild-type mice using the perfused working heart-brainstem preparation (WHBP). We simultaneously recorded phrenic and efferent vagal nerve activities to analyse the motor pattern of respiration, discriminating between inspiration, postinspiration and late expiration. Our results revealed respiratory disturbances in KO preparations that were similar to those reported from in vivo measurements in KO mice and also to those seen in RTT patients. The main finding was a highly variable postinspiratory activity in KO mice that correlated closely with breathing arrhythmias leading to repetitive apnoeas even under undisturbed control conditions. Analysis of the pontine and peripheral sensory regulation of postinspiratory activity in KO preparations revealed: (i) prolonged apnoeas associated with enhanced postinspiratory activity after glutamate-induced activation of the pontine Kölliker-Fuse nucleus; and (ii) prolonged apnoeas and lack of reflex desensitization in response to repetitive vagal stimulations. We conclude that impaired network and sensory mediated synaptic control of postinspiration induces severe breathing dysfunctions in Mecp2-/y KO preparations. As postinspiration is particularly important for the control of laryngeal adductors, the finding might explain the upper airway-related clinical problems of patients with RTT such as apnoeas, loss of speech and weak coordination of breathing and swallowing.

Animals↗
PubMed2006

Treatment of epilepsy in Rett syndrome.

INTRODUCTION: Epilepsy is very frequent in Rett syndrome (RTT) patients and often difficult to treat. Because most cases of RTT are caused by mutations in the MECP2 gene it is reasonable to assume that convulsions are based on common pathogenetic mechanisms and thus should have a similar response to antiepileptic drugs. PURPOSE: To find the optimal treatment for epilepsy in RTT. METHODS: We performed a retrospective study on 110 female patients with confirmed MECP2 mutations. RESULTS: The median age was 10 years, 58% had a history of epilepsy and 55% received antiepileptic drugs (AEDs). Only sulthiame, carbamazepine and valproate were administered in an adequate frequency to allow statistical analysis. The best anticonvulsive results were seen in the RTT group that was treated with carbamazepine. Sulthiame was slightly less effective while valproate was significantly less effective. The rate of side effects was equivalent in all groups. In conclusion, carbamazepine should be recommended as first choice AED in RTT. If carbamazepine is not effective or not well tolerated sulthiame ought to be taken as second choice AED.

Adolescent↗
PubMed2006

Cerebral metabolic and structural alterations in hereditary spastic paraplegia with thin corpus callosum assessed by MRS and DTI.

INTRODUCTION: Hereditary spastic paraplegia with thin corpus callosum (HSP-TCC) is a complicated form of autosomal-recessive hereditary spastic paraplegia. Characteristic clinical features comprise progressive spastic gait, cognitive impairment, and ataxia. Diagnostic MRI findings include thinning of the corpus callosum and non-progressive white matter (WM) alterations. METHODS: To study the extent of axonal involvement, we performed localized proton magnetic resonance spectroscopy (MRS) of the cerebral WM and cortical grey matter (GM) in a patient with HSP-TCC at 20 and 25 years of age. The second investigation included diffusion tensor imaging (DTI). RESULTS: While MRS of the GM was normal, affected WM was characterized by major metabolic alterations such as reduced concentrations of N-acetylaspartate and N-acetylaspartyl-glutamate, creatine and phosphocreatine, and choline-containing compounds as well as elevated levels of myo-inositol. These abnormalities showed progression over a period of 5 years. DTI revealed increased mean diffusivity as well as reduced fractional anisotropy in periventricular WM. The metabolic and structural findings are consistent with progressive neuroaxonal loss in the WM accompanied by astrocytic proliferation-histopathological changes known to occur in HSP-TCC. CONCLUSION: Our results are in agreement with the hypothesis that the primary pathological process in HSP-TCC affects the axon, possibly due to impaired axonal trafficking.

Adult↗
PubMed2006

X-linked adrenoleukodystrophy: clinical, biochemical and pathogenetic aspects.

X-linked adrenoleukodystrophy (X-ALD) is a clinically heterogeneous disorder ranging from the severe childhood cerebral form to asymptomatic persons. The overall incidence is 1:16,800 including hemizygotes as well as heterozygotes. The principal molecular defect is due to inborn mutations in the ABCD1 gene encoding the adrenoleukodystrophy protein (ALDP), a transporter in the peroxisome membrane. ALDP is involved in the transport of substrates from the cytoplasm into the peroxisomal lumen. ALDP defects lead to characteristic accumulation of saturated very long-chain fatty acids, the diagnostic disease marker. The pathogenesis is unclear. Different molecular mechanisms seem to induce inflammatory demyelination, neurodegeneration and adrenocortical insufficiency involving the primary ABCD1 defect, environmental factors and modifier genes. Important information has been derived from the X-ALD mouse models; species differences however complicate the interpretation of results. So far, bone marrow transplantation is the only effective long-term treatment for childhood cerebral X-ALD, however, only when performed at an early-stage of disease. Urgently needed novel therapeutic strategies are under consideration ranging from dietary approaches to gene therapy.

ATP Binding Cassette Transporter, Subfamily D, Mem↗
PubMed2006

Detection of tripeptidyl peptidase I activity in living cells by fluorogenic substrates.

Tripeptidyl peptidase I (TPP-I) is a lysosomal peptidase with unclear physiological function. TPP-I deficiency is associated with late-infantile neuronal ceroid lipofuscinosis (NCL), a fatal neurodegenerative disease of childhood that is characterized by loss of neurons and photoreceptor cells. We have developed two novel fluorogenic substrates, [Ala-Ala-Phe]2-rhodamine 110 and [Arg-Nle-Nle]2-rhodamine 110, that are cleaved by TPP-I in living cells. Fluorescence of liberated rhodamine 110 was detected by flow cytometry and was dependent on the level of TPP-I expression. Rhodamine-related fluorescence could be suppressed by preincubation with a specific inhibitor of TPP-I. When investigated by fluorescent confocal microscopy, rhodamine signals colocalized with lysosomal markers. Thus, cleavage of these rhodamide-derived substrates is a marker for mature enzymatically active TPP-I. In addition, TPP-I-induced cleavage of [Ala-Ala-Phe]2-rhodamine 110 could be visualized in primary neurons. We conclude that [Ala-Ala-Phe]2-rhodamine 110 and [Arg-Nle-Nle]2-rhodamine 110 are specific substrates for determining TPP-I activity and intracellular localization in living cells. Further, these substrates could be a valuable tool for studying the neuronal pathology underlying classical late-infantile NCL. This article contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Aminopeptidases↗
PubMed2006

Clinical and biochemical spectrum of D-bifunctional protein deficiency.

OBJECTIVE: D-bifunctional protein deficiency is an autosomal recessive inborn error of peroxisomal fatty acid oxidation. Although case reports and small series of patients have been published, these do not give a complete and balanced picture of the clinical and biochemical spectrum associated with this disorder. METHODS: To improve early recognition, diagnosis, prognosis, and management of this disorder and to provide markers for life expectancy, we performed extensive biochemical studies in a large cohort of D-bifunctional protein-deficient patients and sent out questionnaires about clinical signs and symptoms to the responsible physicians. RESULTS: Virtually all children presented with neonatal hypotonia and seizures and died within the first 2 years of life without achieving any developmental milestones. However, within our cohort, 12 patients survived beyond the age of 2 years, and detailed information on 5 patients with prolonged survival (> or =7.5 years) is provided. INTERPRETATION: Biochemical analyses showed that there is a clear correlation between several biochemical parameters and survival of the patient, with C26:0 beta-oxidation activity in cultured skin fibroblasts being the best predictive marker for life expectancy. Remarkably, three patients were identified without biochemical abnormalities in plasma, stressing that D-bifunctional protein deficiency cannot be excluded when all peroxisomal parameters in plasma are normal.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed2006

The cystathionine beta-synthase variant c.844_845ins68 protects against CNS demyelination in X-linked adrenoleukodystrophy.

The clinical course of X-linked adrenoleukodystrophy (X-ALD) is of unexplained heterogeneity. Major X-ALD phenotypes are the progressive childhood cerebral form (CCALD) with early confluent cerebral demyelination and the adult-onset adrenomyeloneuropathy (AMN). Adult AMN may present with demyelinated foci of the CNS (adrenoleukomyeloneuropathy, ALMN) or without ("pure" AMN). Activated methionine is essential for CNS myelination, and methionine metabolism is important for glutathione synthesis, which may influence neurodegeneration. Cystathionine beta-synthase (CBS) is a key enzyme of methionine metabolism. The CBS variant c.844_845ins68 (p.-) may influence the availability of activated methionine as well as of glutathione. In this study, we analyzed this variant in genomic DNA samples of 86 X-ALD patients. We observed the allele carrying the insertion in 12 of 49 patients without CNS demyelination ("pure" AMN), but in none of the 37 patients with CNS demyelination (CCALD or ALMN; chi(2)=10.531; p=0.001). We conclude that the insertion allele of CBS c.844_845ins68 protected X-ALD patients against CNS demyelination in our study sample. These data suggest that the individual conditions in methionine metabolism may be a disease modifier of X-ALD. Since methionine metabolism can easily be influenced by vitamin and amino acid substitution, this observation could be a basis of novel treatment strategies in this yet untreatable disease. (c) 2006 Wiley-Liss, Inc.

Adrenoleukodystrophy↗
PubMed2006

Identification of novel mutations in PEX2, PEX6, PEX10, PEX12, and PEX13 in Zellweger spectrum patients.

Mutations in each of the 13 identified human PEX genes are known to cause a peroxisomal biogenesis defect (PBD). Affected patients can be divided into two broad clinical spectra: the Zellweger spectrum, which accounts for about 80% of PBD patients, and the rhizomelia chondrodysplasia punctata (RCDP) spectrum. The clinical continuum of Zellweger spectrum patients extends from Zellweger syndrome (ZS) as the prototype and the most severe entity of this group to neonatal adrenoleukodystrophy (NALD) as an intermediate form and infantile Refsum (IRD) disease as the mildest variant. Characteristic features of ZS patients are dysmorphic features, severe neurological impairment, liver dysfunction, and eye and skeletal abnormalities. Similar but less severe clinical signs are seen in patients with NALD and IRD. In this study ten clinically and/or biochemically well-characterized patients with classical ZS were investigated for defects in all known human PEX genes. We identified two novel mutations in PEX2 (official symbol, PXMP3), two novel mutations in PEX6, two novel mutations in PEX10, one novel mutation in PEX12, and one novel mutation in PEX13.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2006

Pediatric multiple sclerosis: detection of clinically silent lesions by multimodal evoked potentials.

Pediatric patients with multiple sclerosis (MS) frequently do not meet MRI criteria for diagnosis because of lack of evidence of dissemination in space. We assessed the diagnostic utility of multimodal evoked potentials (EP). In 46% of 85 childhood patients with MS, spatial dissemination was detected by EP before the second clinical attack. EP may constitute an important tool for earlier diagnosis of pediatric MS.

Adolescent↗
PubMed2005

Mutation analysis of the HDAC 1, 2, 8 and CDKL5 genes in Rett syndrome patients without mutations in MECP2.

Mutations in the MECP2 gene are found in only 80% of patients with Rett syndrome (RTT). Therefore other genes have to be involved in the pathogenesis of RTT. By using our defined diagnostic criteria we first re-evaluated 50 girls with possible RTT in whom the sequencing of the MECP2 gene had not revealed any mutations. Only 15 of theses patients fulfilled all criteria for RTT and could be considered to have classical RTT. In eight of these, further molecular analyses revealed large deletions of the MECP2 gene. In the remaining seven girls we then analyzed the genes HDAC1, HDAC2, and HDAC8 that encode for the histone deacetylases 1, 2, and 8 which interact with MeCP2 and are essential for its function. Although these histone deacetylase genes have been considered as good candidate genes for RTT our molecular analysis of these genes did not detect any mutations. Because recently mutations in CDKL5 were reported in patients with RTT, we included this gene in our analysis but failed to detect any mutations. We conclude that only a subgroup of girls with possible RTT and no detectable mutation in the sequencing of the MECP2 gene do really have classical RTT. In many of those large MECP2 gene deletions can be detected by further analysis. The genes HDAC1, HDAC2, and HDAC8 do not seem to play a role in the pathogenesis of RTT and at least in our subgroup no mutations in the CDKL5 gene were detected.

Cell Cycle Proteins↗
PubMed2005

Treatment of early onset multiple sclerosis with subcutaneous interferon beta-1a.

The authors studied the tolerability of subcutaneous interferon beta-1a (IFNbeta-1a) in 51 patients with early-onset multiple sclerosis. The most frequent systemic adverse effects were flu-like symptoms in 65%. Laboratory abnormalities included asymptomatic leukopenia (27%) and elevated hepatic transaminases (35%). Treatment with IFNbeta-1a was safe and well tolerated in the majority of children and adolescents.

Adjuvants, Immunologic↗
PubMed2005

Colorectal cancer in two pre-teenage siblings with familial adenomatous polyposis.

UNLABELLED: Familial adenomatous polyposis (FAP) is an autosomal dominant disorder that characteristically presents with colon cancer in early adult life. We describe a Pakistani FAP family in which two sons had an unusually early manifestation of colorectal cancer. The index patient presented at 11 years of age with abdominal pain, rectal bleeding and iron deficiency anaemia. Colonoscopy showed that the colon was carpeted with a myriad of polyps. Oesophago-gastric and duodenal endoscopy revealed that polyps had also developed in the duodenum. Multiple biopsies indicated neoplastic lesions. The patient underwent a proctocolectomy and endoscopic duodenal mucosectomy. The diagnosis of an adenocarcinoma of the colon and further adenomatous polyps with low-grade and high-grade dysplasia was confirmed by histology. Family screening including a blood test for anaemia and bowel examination revealed that his 12-year-old brother was also affected. CONCLUSION: Children with familial adenomatous polyposis are at risk for colon cancer and emphasise the need for early tumour recognition. Gastrointestinal symptoms in children should be thoroughly evaluated and standard screening for colonic polyposis should be performed in all individuals with a positive family history and/or known mutations in cancer-associated genes, particularly in children who are under 10 years of age.

Abdominal Pain↗
PubMed2005

Identification of ten novel mutations in patients with eIF2B-related disorders.

Autosomal recessive inherited mutations in each of the five eukaryotic initiation factor 2B (eIF2B) subunits are known to cause white matter abnormalities with a wide continuum of clinical signs and severity leading to the concept of eIF2B-related disorders. The clinical spectrum extends from fatal infantile forms to adult forms with slow or absent neurological deterioration. In this study 15 well-characterised patients with the classical form of leukoencephalopathy with vanishing white matter (VWM) or with phenotypic variants like ovarioleukodystrophy were investigated for mutations in the genes EIF2B1, EIF2B2, EIF2B3, EIF2B4, and EIF2B5 encoding eIF2B. We identified one novel nonsense mutation (EIF2B4, c.625C>T, p.Arg209X), one novel frameshift mutation (EIF2B5, c.453_454del, p.Tyr152fsX12), eight novel missense muations (EIF2B1, c.547G>T, p.Val183Phe; EIF2B2, c. 586C>T, p.Pro196Ser; EIF2B4, c.806T>G, p.Leu269Arg; EIF2B5, c.203T>C, p.Leu68Ser; EIF2B5, c.220G>A, p.Ala74Thr; EIF2B5, c.805C>G, p.Arg269Gly; EIF2B5, c.929G>T, p.Cys310Phe; EIF2B5, c.1003T>C, p.Cys335Arg), and eight previously described alterations.

Adolescent↗
PubMed2005

A decreasing rate of neural tube defects following the recommendations for periconceptional folic acid supplementation.

BACKGROUND/AIM: Neural tube defects (NTDs) are the most common birth defects, resulting in severe mortality and morbidity. In 1995, the supplementation of folic acid periconceptionally was officially recommended in Germany. The impact of the recommendations on the rate of NTDs was assessed. METHODS: An active surveillance system was established in the northern Rhine area. From 1996, all departments of obstetrics were asked to report cases of NTDs in all abortions, live births and stillbirths. Compliance with the recommendations was evaluated in a sample of mothers who delivered at the Department of Obstetrics of Düsseldorf University in 2001. RESULTS: From 1996-2003, 520 NTDs were reported. Compared to the rate of NTDs in 1996 (10.5/10,000), the average incidence in the years 1997 to 2003 dropped (6.8/10,000). The intake of folic acid, as recommended, was low among the general population (21.1%). CONCLUSION: Active surveillance data on the rate of NTDs are compatible with the maximum decrease of about 20% to be expected from data on the implementation of the recommendations. A much greater decrease in NTDs should be the challenge for the future.

Anencephaly↗
PubMed2005

Visually self-induced seizures sensitive to round objects.

PURPOSE: To describe a previously unreported type of self-induced pattern-sensitive seizures in a child. METHODS: Evaluation of clinical and EEG features. RESULTS: An 18-month-old boy was initially seen with series of short focal tonic seizures self-induced by gazing intermittently at round objects. Self-induction of these seizures had an obvious relieving effect on the child. Covering the round object foiled further seizures but resulted in a tantrum. Later in the course, an increasing variety of patterns proved to be capable of inducing seizures, which occurred with increasing frequency and severity, including secondarily generalized tonic-clonic seizures. Interictal EEG revealed multifocal sharp-and-slow-waves. Ictal EEG showed no abnormalities during short focal seizures and rapidly generalizing epileptic discharges during a secondarily generalized seizure. No photosensitivity was noted. Motor and mental development of the boy stagnated over a period of 2 years. Behavioral therapy as well as medical treatment, consisting of various combinations of antiepileptic drugs (AEDs) together with a selective serotonin-reuptake inhibitor, were of merely transient benefit. Only combined pharmacotherapy, including valproate, sulthiame, and clobazam, resulted in seizure control at age 3 years 9 months. CONCLUSIONS: Visual capture of geometric patterns other than stripes or gratings may trigger focal seizures with secondary generalization. Synchronization of cortical neurons responsible for pattern recognition may account for epileptogenesis in this child.

Age Factors↗
PubMed2005

Molecular diagnosis of Rett syndrome.

In 1999, mutations in the MECP2 gene were identified as the primary cause of Rett syndrome. MECP2 mutations can be found in 70% to 80% of all clinically defined Rett syndrome cases; in classic Rett syndrome, this frequency is even higher. In most cases, missense and nonsense mutations affecting functionally important domains can be found. Additionally, a hot spot for small deletions has been defined, and several gross rearrangements have also been described. Among female individuals with Rett syndrome, the spectrum of clinical phenotypes is broad, but most fulfill the diagnostic criteria. In contrast, male individuals with mutations in the MECP2 gene are rare, and only a minority have clinical symptoms resembling Rett syndrome.

Female↗
PubMed2005

Tau, phospho-tau, and S-100B in the cerebrospinal fluid of children with multiple sclerosis.

Axonal injury and glial activation are an early neuropathologic event in adults with multiple sclerosis. To investigate whether markers of axonal injury and glial activation are already elevated in the cerebrospinal fluid of children with multiple sclerosis, we studied the cerebrospinal fluid of 25 children with multiple sclerosis and 67 controls for the presence of tau, phospho-tau, and S-100B proteins using specific enzyme-linked immunoabsorbent assays. In general, tau, phospho-tau, and S-100B protein levels did not differ significantly between groups. However, in a subgroup of nine children with multiple sclerosis, all of whom had prominent clinical symptoms at the time of lumbar puncture and radiologic disease activity, tau protein levels were significantly elevated when compared with other controls. These data indicate that axonal injury is not restricted to adult multiple sclerosis but can already occur in children with multiple sclerosis.

Adolescent↗