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Biomedical subjects

C Klein

Publications and source records attributed to C Klein.

At least 73 records · Page 4Linked to original sources
PubMed2003

Gene therapy to target dendritic cells from blood to lymph nodes.

Peripheral lymph nodes (PLN) are strategic microenvironments where antigen-presenting dendritic cells (DC), loaded with environmental antigens, and naive lymphocytes meet to initiate immune responses. The unique capacity of DC to induce primary immune responses has led to their use in clinical medicine; however, delivering DC to lymph nodes is problematic. Intravenously injected DC cannot access to PLN, while DC injected into tissue migrate inefficiently through lymphatics to PLN. We achieved DC targeting to T-cell areas of PLN by endowing DC with a novel receptor for peripheral node addressin (PNAd), an adhesion molecule present on the lymph node venular endothelium. This novel receptor is a chimeric E/L-selectin (ELS) that, we have previously shown, binds to PNAd. DC were genetically modified by retroviral transduction to express ELS. ELS expression was targeted to tips of microvilli, and mediated rolling of DC on PNAd both in vivo and in vitro. Such genetically engineered DC could extravasate directly from blood through the lymph node endothelium as opposed to nontransduced DC. This study provides evidence that the trafficking of DC can be modified using gene transfer technologies. More efficient delivery of DC to PLN should assist the development of improved vaccination strategies.

Adoptive Transfer↗
PubMed2003

Delivery of antisense oligonucleotide to the cornea by iontophoresis.

We wished to evaluate the potential of iontophoresis to promote the delivery of antisense oligonucleotides (ODN) directed at the vascular endothelial growth factor (VEGF)-R2 receptor (KDR/Flk) to the cornea of the rat eye. Fluorescence (CY5)-labeled ODNs in phosphate-buffered saline (PBS) (20 microM) were locally administered to rat eyes, and their fate within the anterior segment was studied. Thirty-four male, 5-week-old Wistar rats were used for all experiments. The rats were divided in four groups. In group I (12 rats, 12 eyes), the ODNs (20 microM) were delivered by iontophoresis (300 microA for 5 minutes) using a specially designed corneal applicator. In group II (12 rats, 12 eyes), the ODNs (20 microM) were delivered using the same applicator, but no electrical current was applied. In group III (6 rats, 6 eyes), a corneal neovascular reaction was induced prior to the application of ODNs (20 microM), and iontophoresis electrical current was delivered as for group I rats. Group IV (4 rats, 4 eyes) received ODN (60 microM) iontophoresis application (300 microA for 5 minutes) and were used for ODN integrity studies. The animals were killed 5 minutes, 90 minutes, and 24 hours after a single ODN application and studied. Topically applied ODNs using the same iontophoresis applicator but without current do not penetrate the cornea and remain confined to the superficial epithelial layer. ODNs delivered with transcorneoscleral iontophoresis penetrate into all corneal layers and are also detected in the iris. In corneas with neovascularization, ODNs were particularly localized within the vascular endothelial cells of the stroma. ODNs extracted from eye tissues 24 hours after iontophoresis remained unaltered. The iontophoresis current did not cause any detectable ocular damage under these conditions. Iontophoresis promotes the delivery of ODNs to the anterior segment of the eye, including all corneal layers. Iontophoresis of ODNs directed at VEGF-R2 may be used for the design of specific antiangiogenic strategy in diseases of the cornea.

Animals↗
PubMed2002

Exon deletions in the GCHI gene in two of four Turkish families with dopa-responsive dystonia.

Most cases of dopa-responsive dystonia (DRD) are thought to be caused by mutations in the GCHI gene; however, by sequencing, mutations are found in only 40% to 60%. Recently, a single report identified, via Southern blot analysis, a large genomic GCHI deletion in a "mutation-negative" case. This report describes four families with DRD, two of which carry large deletions, thus confirming that deletions are an important subtype of GCHI mutations. These deletions were detected by quantitative duplex PCR that is amenable to DNA diagnostics.

Adult↗
PubMed2002

Phenotypic features of myoclonus-dystonia in three kindreds.

BACKGROUND: Myoclonus-dystonia (M-D) is a movement disorder with involuntary jerks and dystonic contractions. Autosomal dominant alcohol-responsive M-D is associated with mutations in the epsilon-sarcoglycan gene (SGCE) (six families) and with a missense change in the D2 dopamine receptor (DRD2)gene (one family). OBJECTIVE: To investigate the clinical phenotype associated with M-D including motor symptoms, psychiatric disorders, and neuropsychological deficits. METHODS: Fifty individuals in three M-D families were evaluated and a standardized neurologic examination and DNA analysis were performed. Psychiatric profiles were established with the Diagnostic Interviews for Genetic Studies (DIGS) and the Yale-Brown Obsessive-Compulsive Scale (YBOCS). Cognition was evaluated with standardized neuropsychological tests. RESULTS: Distinct truncating mutations in the SGCE gene were identified in each family. Additionally, a missense alteration in the DRD2 gene was previously found in one family. Motor expression was variable, with onset of myoclonus or dystonia or both affecting the upper body and progression to myoclonus and dystonia in most cases. Psychiatric profiles revealed depression, obsessive-compulsive disorder, substance abuse, anxiety/panic/phobic disorders, and psychosis in two families, and depression only in the third family. Averaged scores from cognitive testing showed impaired verbal learning and memory in one family, impaired memory in the second family, and no cognitive deficits in the third family. CONCLUSIONS: Cognitive deficits may be associated with M-D. Psychiatric abnormalities correlate with the motor symptoms in affected individuals. Assessment of additional M-D families with known mutations is needed to determine whether these are characteristic phenotypic manifestations of M-D.

Adult↗
PubMed2002

Clinical findings of a myoclonus-dystonia family with two distinct mutations.

Myoclonus-dystonia has recently been associated with mutations in the epsilon-sarcoglycan gene (SCGE) on 7q21. Previously, the authors reported a patient with myoclonus-dystonia and an 18-bp deletion in the DYT1 gene on 9q34. The authors have now re-evaluated the patient harboring this deletion for mutations in the SGCE gene and identified a missense change. In the current study, the authors describe the clinical details of this family carrying mutations in two different dystonia genes. Further analysis of these mutations separately and together in cell culture and in animal models should clarify their functional consequences.

Adolescent↗
PubMed2002

Neurological features of West Nile virus infection during the 2000 outbreak in a regional hospital in Israel.

During the summer of 2000, 35 patients with West Nile Virus Fever were admitted to our hospital. Of these, the 26 (21 adults, mean age 56 (19-86) and 5 children (aged 9-15)) presented have neurological involvement, 33% with meningitis, 52% with meningoencephalitis, 10% with encephalitis and 5% with acute polyneuropathy. Presenting clinical features were fever in 95% of cases, headache in 90%, nausea/vomiting in 52%, confusion in 48%, somnolence in 38%, neck stiffness in 33%, a skin rash in 19%, diarrhea in 14%, cervical pain in 14%, seizure in 9%, photophobia in 9% and limb weakness in 4%. Leucopenia was not found. Two patients diagnosed with meningoencephalitis died. Three patients had signs of an acute polyneuropathy, this being the only complaint of one patient. The EEG was abnormal in all cases of meningitis or meningoencephalitis, except in three cases. Outbreaks of West Nile Virus Fever are emerging as a worldwide disease with high rates of neurological involvement and death. It should be considered in cases presenting with aseptic meningoencephalitis, meningitis and acute polyneuropathy, especially during the summer months and in areas along bird migration pathways.

Adolescent↗
PubMed2002

Dopamine transmission in DYT1 dystonia: a biochemical and autoradiographical study.

Indices of dopamine transmission were measured in the postmortem striatum of DYT1 dystonia brains. A significant increase in the striatal 3,4-dihydroxyphenylacetic acid/dopamine ratio was found. Quantitative autoradiography revealed no differences in the density of dopamine transporter or vesicular monoamine transporter-2 binding; however, there was a trend toward a reduction in D(1) receptor and D(2) receptor binding. One brain with DYT1 parkinsonism was similarly evaluated and marked reductions in striatal dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid content as well as the density of binding of all four dopaminergic ligands were measured.

Autoradiography↗
PubMed2002

Novel three-stage ascertainment method: prevalence of PD and parkinsonism in South Tyrol, Italy.

BACKGROUND: A number of community-based studies on the prevalence of PD have been conducted worldwide, but they are often extremely costly and time consuming. OBJECTIVE: To assess the prevalence of PD and parkinsonism for the population aged between 60 and 85 years in South Tyrol, Northern Italy, using a novel population-based three-stage ascertainment method. METHODS: Seven hundred fifty persons aged 60 to 85 years from South Tyrol received a validated screening mail questionnaire for parkinsonism. In the second stage of the ascertainment method, trained primary care physicians (PCP) identified all persons with possible parkinsonism among those screened positive. In the third stage, movement disorders specialists excluded or confirmed the diagnosis in all identified people. RESULTS: The response rate was 87.6%. The prevalence rate per 100 population over 65 years of age was 1.5 (95% CI 0.6 to 2.3) for PD and 2.2 (95% CI 1.2 to 3.3) for parkinsonism after having been adjusted to the 1991 European standard population. Overall, 78% (95% CI 59 to 96%) of patients with parkinsonism were newly detected through the survey. CONCLUSIONS: The prevalence of PD and parkinsonism in people aged over 65 in South Tyrol was similar to that observed in door-to-door surveys in other European countries. The novel three-stage case ascertainment method employed proved a useful tool to substitute for expensive door-to-door surveys for prevalence studies of parkinsonism, detecting a high number of undiagnosed cases, particularly in geographically remote areas.

Aged↗
PubMed2002

Two-dimensional oxide on Pd(111).

The oxidation of Pd(111) leads to an incommensurate surface oxide, which was studied by the use of scanning tunneling microscopy, surface x-ray diffraction, high resolution core level spectroscopy, and density functional calculations. A combination of these methods reveals a two-dimensional structure having no resemblance to bulk oxides of Pd. Our study also demonstrates how the atomic arrangement of a nontrivial incommensurate surface can be solved by molecular dynamics in a case where experimental techniques alone give no solution.

Journal Article↗
PubMed2002

Effects of methylphenidate on saccadic responses in patients with ADHD.

This study examined the effects of methylphenidate on different measures of saccade control, using a repeated measurement design, and the experimental and statistical control of practice effects. Twenty-seven boys with ADHD (mean age 12.6 years, range 10-15 years) were randomly assigned to two testing order conditions (first on-, second off-medication versus first off-, second on-medication) and accomplished the pro-saccadic overlap and the anti-saccadic 200-ms gap tasks (200 trials each). Methylphenidate was found to reduce pro- and anti-saccadic reaction times, error correction times, and the proportion of direction errors during the anti-saccade task. Furthermore, the drug augmented the proportions of express saccades and error corrections. Overlain practice effects were found for most of these measures. Our results suggest a weakening of the fixation, and a strengthening of the "voluntary" system of saccade control by methylphenidate.

Adolescent↗
PubMed2002

Evaluation of 50 probands with early-onset Parkinson's disease for Parkin mutations.

BACKGROUND: Early onset PD has been associated with different mutations in the Parkin gene, including exon deletions and duplications. METHODS: The authors performed an extensive mutational analysis on 50 probands with onset of PD at younger than 50 years of age. Thirteen probands were ascertained from a registry of familial PD and 37 probands by age at onset at younger than 50 years, blind to family history. Mutational analysis was undertaken on the probands and available family members and included conventional techniques (single strand conformation polymorphism analysis and sequencing) and a newly developed method of quantitative duplex PCR to detect alterations of gene dosage (exon deletions and duplications) in PARKIN: RESULTS: Using this new technique, the authors detected eight alterations of gene dosage in the probands, whereas 12 mutations were found by conventional methods among the probands and another different mutation in an affected family member. In total, the authors identified compound heterozygous mutations in 14%, heterozygous mutations in 12%, and no Parkin mutation in 74% of the 50 probands. We expanded the occurrence of Parkin mutations to another ethnic group (African-American). CONCLUSION: The authors systematically screened all 12 Parkin exons by quantitative PCR and conventional methods in 50 probands. Eight mutations were newly reported, 2 of which are localized in exon 1, and 38% of the mutations were gene dosage alterations. These results underline the need to screen all exons and to undertake gene dosage studies. Furthermore, this study reveals a frequency of heterozygous mutation carriers that may signify a unique mode of inheritance and expression of the Parkin gene.

Adult↗
PubMed2002

Parkin mutations in a patient with hemiparkinsonism-hemiatrophy: a clinical-genetic and PET study.

The authors describe a 37-year-old woman with early-onset hemiparkinsonism (HP) and ipsilateral body hemiatrophy (HA). Genetic analysis revealed a missense mutation (Arg275Trp) and a duplication of exon 7 of parkin. The complementary metabolic and receptor pattern of PET ligands corresponded to that typically found in idiopathic PD, although tracer binding asymmetry was lacking. Parkin mutations should be considered in HPHA, particularly when there is a younger age at onset and dystonia is an early sign.

Adult↗
PubMed2002

Myoclonus dystonia: possible association with obsessive-compulsive disorder and alcohol dependence.

BACKGROUND: Inherited myoclonus-dystonia (M-D) is a disorder that is characterized primarily by myoclonic jerks and is often accompanied by dystonia. In addition to motor features, psychiatric disease is reported in some families. METHODS: To determine whether the same genetic etiology underlies both neurologic and psychiatric signs, the authors studied psychiatric symptoms in nonmanifesting carriers (NMC), noncarriers (NC), and manifesting carriers (MC) in three families demonstrating linkage of M-D to the 7q21 locus. Interviewers administered the computerized version of the Composite International Diagnostic Interview. Algorithms for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of obsessive-compulsive disorder (OCD), generalized anxiety disorder, major affective disorder, alcohol abuse, alcohol dependence, drug abuse, and drug dependence were used. Rates of disorders among the MC, NMC, and NC were compared. RESULTS: Of 55 participating individuals, 16 were MC, 11 were NMC, and 28 were NC. The rate of OCD was greater in carriers (5/27) compared with NC (0/28) (p = 0.023). It was also greater in the symptomatic gene carriers (4/16) compared with the asymptomatic group (1/11) (p = 0.022). Alcohol dependence was increased in the symptomatic carriers (7/16) (p = 0.027), but not in the carrier group overall (7/27). CONCLUSION: OCD may be associated with the DYT11 M-D gene; however, a larger sample is necessary to confirm this finding. Alcohol dependence is highly associated with expressing symptoms of M-D. This may be explained by self-medication with alcohol to improve motor symptoms of M-D.

Adolescent↗
PubMed2002

Epidemiologic study of 203 sibling pairs with Parkinson's disease: the GenePD study.

OBJECTIVE: To examine patterns of familial aggregation and factors influencing onset age in a sample of siblings with PD. METHODS: Sibling pairs (n = 203) with PD were collected as part of the GenePD study. Standardized family history, medical history, and risk factor data were collected and analyzed. RESULTS: The mean age at onset was 61.4 years and did not differ according to sex, exposure to coffee, alcohol, or pesticides. Head trauma was associated with younger onset (p = 0.03) and multivitamin use with later onset (p = 0.007). Age at onset correlation between sibling pairs was significant (r = 0.56, p = 0.001) and was larger than the correlation in year of onset (r = 0.29). The mean difference in onset age between siblings was 8.7 years (range, 0 to 30 years). Female sex was associated with increased frequency of relatives with PD. The frequency of affected parents (7.0%) and siblings (5.1%) was increased when compared with frequency in spouses (2.0%). CONCLUSIONS: The greater similarity for age at onset than for year of onset in sibling pairs with PD, together with increased risk for biological relatives over spouses of cases, supports a genetic component for PD. Risk to siblings in this series is increased over that seen in random series of PD cases; however, patients in this sample have similar ages at onset and sex distribution as seen for PD generally. These analyses suggest that factors influencing penetrance are critical to the understanding of this disease.

Age of Onset↗
PubMed2002

[CDG (congenital disorders of glycosylation). Differential hereditary ataxia in adulthood diagnosis].

Congenital disorders of glycosylation (CDG) are a group of hereditary multisystem diseases due to different defects of enzymes or transport molecules involved in the synthesis of glycoproteins. CDG-la is the most common subtype, with cerebellar ataxia as the main neurological symptom. Currently there is little information about CDG-la manifestation in adulthood. Here we present two sisters in whom the diagnosis of CDG-la was made in the fourth decade of life and who to our knowledge are the oldest known patients with the disorder in Germany. The clinical course of the disease was typical, although less severe than previously described. The carbohydrate-deficient transferrin (CDT) level was increased but lower than in other CDG patients. Isoelectric focusing of transferrin revealed changes typical of CDG, whereas those of alpha 1-antitrypsin were only moderately pathologic. This might be due to the milder manifestation of the disease in our patients or it could be indicative of a stabilization of the disease after puberty. The CDG should be included in the differential diagnostic workup of hereditary cerebellar ataxia in adults.

Adult↗
PubMed2001

NMR spectroscopy reveals the solution dimerization interface of p53 core domains bound to their consensus DNA.

The p53 protein is a transcription factor that acts as the major tumor suppressor in mammals. The core DNA-binding domain is mutated in about 50% of all human tumors. The crystal structure of the core domain in complex with DNA illustrated how a single core domain specifically interacts with its DNA consensus site and how it is inactivated by mutation. However, no structural information for the tetrameric full-length p53-DNA complex is available. Here, we present novel experimental insight into the dimerization of two p53 core domains upon cooperative binding to consensus DNA in solution obtained by NMR. The NMR data show that the p53 core domain itself does not appear to undergo major conformational changes upon addition of DNA and elucidate the dimerization interface between two DNA-bound core domains, which includes the short H1 helix. A NMR-based model for the dimeric p53 core-DNA complex incorporates these data and allows the conclusion that the dimerization interface also forms the actual interface in the tetrameric p53-DNA complex. The significance of this interface is further corroborated by the finding that hot spot mutations map to the H1 helix, and by the binding of the putative p53 inhibitor 53BP2 to this region via one of its ankyrin repeats. Based on symmetry considerations it is proposed that tetrameric p53 might link non-contiguous DNA consensus sites in a sandwich-like manner generating DNA loops as observed for transcriptionally active p53 complexes.

Amino Acid Sequence↗
PubMed2001

Genome-wide scan for Parkinson's disease: the GenePD Study.

A genome-wide scan for idiopathic PD in a sample of 113 PD-affected sibling pairs is reported. Suggestive evidence for linkage was found for chromosomes 1 (214 cM, lod = 1.20), 9 (136 cM, lod = 1.30), 10 (88 cM, lod = 1.07), and 16 (114 cM, lod = 0.93). The chromosome 9 region overlaps the genes for dopamine beta-hydroxylase and torsion dystonia. Although no strong evidence for linkage was found for any locus, these results may be of value in comparison with similar studies by others.

Aged↗