Biomedical subjects

S Wieczorek

Publications and source records attributed to S Wieczorek.

7 recordsLinked to original sources

PubMed2003

A novel splice site mutation in the TRIM37 gene causes mulibrey nanism in a Turkish family with phenotypic heterogeneity.

Mulibrey nanism (muscle-liver-brain-eye nanism; MUL) is an autosomal recessively transmitted disease characterized by severe growth delays of prenatal onset caused by mutations in the TRIM37 gene. Recent studies on the subcellular localization revealed that the TRIM37 (KIAA0898) protein is located in peroxisomes. Therefore, MUL has been classified as a new peroxisomal disorder. Up to now, four mutations have been reported, all of which lead to frameshifts and truncated proteins. In this study, mutation screening was performed for the coding region of the TRIM37 gene in a Turkish family by means of RT-PCR and direct cDNA sequencing. We have identified a novel mutation resulting in a frameshift cosegregating within the family. Finally, we report on the presence of novel splice variants observed in lymphoblastoid cells and muscle tissue of normal subjects and patients.

Base Sequence↗

PubMed2003

TNFA promoter polymorphisms and narcolepsy.

Narcolepsy is a debilitating sleep disorder that affects up to 0.05% of individuals in Caucasian populations. It is highly associated with the HLA-DR2 group antigen or the HLA-DRB1*1501-DQB1*0602 haplotype, respectively. However, the HLA association by itself cannot sufficiently explain the increased risk to family members, as HLA-DR2 is quite common in the general population and most people harboring the respective genotype do not develop any symptoms of narcolepsy. Situated in the HLA class II region, the TNFA gene is translated into the pro-inflammatory cytokine TNF-alpha. TNFA promoter polymorphisms have been linked to several inflammatory and autoimmune diseases. We analyzed three SNP of the TNFA promoter and one adjacent microsatellite in 103 patients and 96 controls. The T-allele of the C-857T polymorphism was strongly associated with narcolepsy in the subgroup of DRB1*15/16 (HLA-DR2 type) negative patients, but not in DRB1*15/16 positive patients. These results point towards an etiological influence of TNFA alleles in narcolepsy and support previous findings suggesting genetic heterogeneity and differences in pathophysiological characteristics of HLA-DR2 positive and negative narcolepsy.

Alleles↗

PubMed2003

Increased frequency of migraine in narcoleptic patients: a confirmatory study.

Previously we have reported an increased prevalence of migraine in narcoleptic patients. Because of the theoretical and clinical implications of this finding we recruited an independent new study sample of 100 patients with proven narcolepsy and conducted a structured 26-item interview based on the international diagnostic criteria for headache disorders, the Kiel Headache Questionnaire. Narcolepsy symptoms were measured by means of the Stanford Centre for Narcolepsy Sleep Inventory. Migraine prevalence was twofold to fourfold increased in the narcoleptic patients and amounted to 44.4% in women and 28.3% in men. The onset of narcolepsy symptoms was 12.3 +/- 11.4 years before the onset of migraine symptoms. The results might be regarded as indicative of a common pathophysiological pathway relevant to both of the two disorders.

Adult↗

PubMed2001

Unnested islands of period doublings in an injected semiconductor laser.

We present a theoretical study of unnested period-doubling islands in three-dimensional rate equations modeling a semiconductor laser subject to external optical injection. In this phenomenon successive curves of period doublings are not arranged in nicely nested islands, but intersect each other. This overall structure is globally organized by several codimension-2 bifurcations. As a consequence, the chaotic region existing inside an unnested island of period doublings can be entered not only via a period-doubling cascade but also via the breakup of a torus, and even via the sudden appearance of a chaotic attractor. In order to fully understand these different chaotic transitions we reveal underlying global bifurcations and we show how they are connected to codimension-2 bifurcation points. Unnested islands of period doublings appear to be generic and hence must be expected in a large class of dynamical systems.

Journal Article↗

PubMed2001

ApoE polymorphisms in narcolepsy.

BACKGROUND: Narcolepsy is a common neuropsychiatric disorder characterized by increased daytime sleepiness, cataplexy and hypnagogic hallucinations. Deficiency of the hypocretin neurotransmitter system was shown to be involved in the pathogenesis of narcolepsy in animals and men. There are several hints that neurodegeneration of hypocretin producing neurons in the hypothalamus is the pathological correlate of narcolepsy. The ApoE4 allele is a major contributing factor to early-onset neuronal degeneration in Alzheimer disease and other neurodegenerative diseases as well. METHODS: To clarify whether the ApoE4 phenotype predisposes to narcolepsy or associates with an earlier disease onset, we have genotyped the ApoE gene in 103 patients with narcolepsy and 101 healthy controls. RESULTS: The frequency of the E4 allele of the ApoE gene was 11% in the patient and 15% in the control groups. Furthermore, the mean age of onset did not differ between the ApoE4+ and ApoE4- patient groups. CONCLUSION: Our results exclude the ApoE4 allele as a major risk factor for narcolepsy.

Journal Article↗

PubMed2001

A prepro-orexin gene polymorphism is associated with narcolepsy.

The orexin (hypocretin) neurotransmitter system was recently shown to be directly involved in the pathogenesis of narcolepsy in two animal models. Furthermore, decreased levels of orexin A in the CSF were shown in narcoleptic patients. To define any genetic contribution of orexin to the etiology of narcolepsy, the authors screened the entire prepro-orexin gene for mutations or polymorphisms in 133 patients suffering from narcolepsy. They report an association of a rare polymorphism in the prepro-orexin gene with narcolepsy in a cohort of 178 patients.

DNA Primers↗

PubMed1999

Tele-talk: a communication device for the persons with hearing disabilities.

Tele-Talk is a device designed to allow a person with hearing disabilities to communicate using the telephone, with a minimum of effort and without requiring a multitude of special equipment. This device provides a previously unavailable link for the hearing disabled to communicate directly over telephone lines. Tele-Talk has the extra capability of operating in live conference situations using microphone input. Today, most devices designed for the hearing-impaired are dependent on both communicants' owning/operating identical set-ups. If an accessory item is missing or misplaced, communication breaks down. Tele-Talk answers the need to permit transparent hearing assistance via the telephone.

Communication↗