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Biomedical subjects

O Nilssen

Publications and source records attributed to O Nilssen.

At least 19 recordsLinked to original sources
PubMed2005

[Thiamin and ribovlavin status in populations of Arkhangelsk].

It was been performed the epidemiological study of Thiamine and Riboflavin status of 3579 inhabitants in Arkhangelsk. Establish by 49.6% man and 47.4% woman have lower provision of thiamin. Lack of riboflavin reveal by 23.6% man and 21.7% woman. The analysis of the effect of seasonality on vitamins content shown the worst thiamin level in examined population in January-February and in September-October. The worst Riboflavin content observed in examined population in December-January and in July-August.

Adult↗
PubMed2004

Analysis and comparison of the 4b core protein gene of avipoxviruses from wild birds: evidence for interspecies spatial phylogenetic variation.

Avipoxviruses have been isolated from a wide variety of avian hosts, and yet little is known regarding the host-virus species variation of the genus Avipoxvirus. We have investigated the variations in the viral 4b core protein gene from six different avipoxviruses based on PCR, Southern blot and nucleotide sequence analysis to evaluate the suitability of this region for differentiation between avipoxvirus isolates. Southern blot and nucleotide sequence analysis revealed considerable interspecies variation between the different virus isolates. In the deduced amino acid sequences (of 142 residues) of the 4b core protein gene, fowlpox virus vaccine strain (FPV-VR250) was found to be similar to the three poxvirus isolates from great tit (GTV-A310, GTV-A311 and GTV-A256), sparrowpox virus (SPV-A468), and pigeonpox virus (PPV-B7) with similarities of 79.6%, 81%, 81%, 64.8% and 84.5%, respectively. Furthermore, comparative phylogenetic analysis of the aligned DNA sequences revealed divergence among the different viruses that can be consistently correlated to the host.

Amino Acid Sequence↗
PubMed2001

A common ancestral origin of the frequent and widespread 2299delG USH2A mutation.

Usher syndrome type IIa is an autosomal recessive disorder characterized by mild-to-severe hearing loss and progressive visual loss due to retinitis pigmentosa. The mutation that most commonly causes Usher syndrome type IIa is a 1-bp deletion, described as "2299delG," in the USH2A gene. The mutation has been identified in several patients from northern and southern Europe and from North America, and it has been found in single patients from South America, South Africa, and China. Various studies have reported a range of frequencies (.16-.44) among patients with Usher syndrome, depending on the geographic origin of the patients. The 2299delG mutation may be the one that most frequently causes retinitis pigmentosa in humans. Given the high frequencies and the wide geographic distribution of the mutation, it was of interest to determine whether the mutation resulted from an ancestral mutational event or represented a mutational hotspot in the USH2A gene. Haplotype analysis was performed on DNA samples from 116 unrelated patients with Usher syndrome type IIa; the patients were from 14 countries and represented 148 2299delG alleles. On the basis of six single-nucleotide polymorphisms within the USH2A gene, 12 core haplotypes were observed in a panel of normal chromosomes. However, in our analysis, only one core haplotype was found to be associated with the 2299delG mutation. The data indicate that the widespread geographic distribution of the 2299delG mutation is the result of an ancestral mutation that has spread throughout Europe and into the New World as a result of migration.

Alleles↗
PubMed2001

Assessing depression in drug- and alcohol-dependent subjects: the utility of a cognitive-based approach.

Our objective was to report the development of a measure designed to assess depression severity in those with drug and or alcohol problems not confounded by somatic items that may more reflect the impact of drug and alcohol problems rather than depression itself. A questionnaire was derived with 49 items, each assessing cognitive aspects of depression. Subjects with drug and or alcohol problems completed the measure and a standard self-report depression inventory and were assessed for depression presence and severity by a psychiatrist, who used a structured case-finding measure to complement a semi-structured clinical assessment. A high percentage of the sample was found to be depressed. Total scores on the new measure correlated highly with scores on the two other depression reference measures, supporting its validity as a measure of depression severity. A refined set of 14 items was also identified as a valid measure of depression severity, whereas a determined cut-off established high assignment accuracy when examined against the clinical judgement of caseness. In conclusion, the refined 14-item set has been validated as a depression measure in those with drug and alcohol disorders, whereas the item content may assist clinicians to frame screening questions in assessing such patients.

Adult↗
PubMed2000

Identification of novel USH2A mutations: implications for the structure of USH2A protein.

Usher syndrome type II is an autosomal recessive disorder, characterised by stable hearing impairment from childhood and progressive retinitis pigmentosa from the late teens. Mutations in the USH2A gene, located on 1q41, were recently shown to be responsible for Usher syndrome type IIa. We have investigated the molecular pathology of Usher type II by screening the USH2A gene for mutations in 31 unrelated patients from Denmark and Norway. Besides the frequent 2299delG mutation, which accounted for 44% of the disease alleles, a heterogeneous spectrum of mutations was identified. Sixteen new, putative disease-causing mutations were detected, of which 12 were private and four were shared by unrelated patients. The disease-causing mutations were scattered throughout the gene and included six nonsense and seven missense mutations, two deletions and one small insertion. In addition, six non-pathogenic polymorphisms were identified. All missense mutations resulted in major amino acid side-chain alterations. Four missense mutations affected the N-terminal part of USH2A, whereas three missense mutations affected the laminin-type epidermal growth factor-like (LE) domain. The structural consequences of the mutations affecting the LE domain are discussed in relation to the three-dimensional structure of a LE-module of the mouse laminin gamma1 chain.

Adolescent↗
PubMed1999

[Dynamic mutations in hereditary neurodegenerative disorders].

Triplet repeat expansion diseases (TREDs) are characterized by co-incidence between neurological disease manifestation and amplification of specific trinucleotide repeats in different but defined loci. This class of mutations was first identified in 1991 as the cause of spinal and bulbar muscular atrophy (SBMA) and fragile X syndrome (FRAXA). Since then, TNR (tri-nucleotide repeat) expansions have been found to be the causative mechanism in 11 other neurodegenerative disorders. Short cytosine-adenine-guanine (CAG) expansions are characteristic for Huntington's disease (HD), spinal and bulbar muscular atrophy (SBMA), dentatorubral-pallidoluysian atrophy (DRPLA) and spinocerebellar ataxia (SCA) type 1, 2, 3, 6 and 7. In the normal population, the TNR units are polymorphic but transmitted stably from one generation to the next. However, in the above disorders the TNRs are expanded into the disease range and subjected to meiotic instability in a length-dependent manner. Thus, disease-associated, expanded TNRs tend to increase in length from generation to generation. This explains the phenomenon of anticipation associated with these disorders. TNR expansions result in polyglutamine (Q)n expansions in the corresponding proteins. Such mutant proteins tend to precipitate as a result of self-aggregation leading to the formation of neuronal nuclear inclusions and, hence, selective degeneration and loss of neuronal cells.

Anticipation, Genetic↗
PubMed1999

[X-linked recessive bulbospinal neuronopathy--Kennedy's syndrome].

Kennedy's syndrome is an inherited disease which was probably first described 100 years ago. Although rare, a recent report suggests that the prevalence may show considerable regional differences. A review of 30 different names of the disease is given. Originally, the disorder was regarded as a spinal and bulbar muscular atrophy but it is now obvious that there is severe axonal degeneration, also of the sensory fibres with the pattern of a central-peripheral distal axonal neuropathy. This was also present in the two recognized cases presented here. The sensory symptoms develop slowly and it is suggested that a peripheral sprouting compensates for the loss not only of motor, but also sensory fibres. It is important to distinguish the disease from motor neuron diseases since the progression is slow and the expected life span is normal. The clinical presentation with facial palsy and perioral contraction-fasciculations is pathognomonic. However, demonstration of increased (CAG)n repeat size in the androgen receptor gene is diagnostic. A normal (CAG)n repeat size excludes the diagnosis, since the abnormal expansion is the only mutation associated with the disease. Other types of mutations in the androgen receptor gene lead to a different clinical presentation, testicular feminization.

Adult↗
PubMed1999

Characterization of a novel alpha-mannosidosis-causing mutation and its use in leukocyte genotyping after bone marrow transplantation.

Alpha-Mannosidosis is a lysosomal storage disorder caused by deficiency of lysosomal alpha-mannosidase (LAMAN). Major symptoms include mental retardation, skeletal changes and recurrent infections. Recently, a successful bone marrow transplantation (BMT) in an alpha-mannosidosis patient was reported. Here we show that this patient was homozygous for a novel mutation, a 1-bp insertion (1197-1198insA) in exon 9 of the LAMAN gene. By using this mutation as a marker, we demonstrate that 1 year post-BMT, the LAMAN genotype of the patient's leukocytes was identical to that of the donor. This method of genotyping blood cells is a fast and accurate way to monitor the colonization of donor bone marrow cells.

Bone Marrow Transplantation↗
PubMed1999

Spectrum of mutations in alpha-mannosidosis.

alpha-Mannosidosis is an autosomal recessive disorder caused by deficiency of lysosomal alpha-mannosidase (LAMAN). The resulting intracellular accumulation of mannose-containing oligosaccharides leads to mental retardation, hearing impairment, skeletal changes, and immunodeficiency. Recently, we reported the first alpha-mannosidosis-causing mutation affecting two Palestinian siblings. In the present study 21 novel mutations and four polymorphic amino acid positions were identified by the screening of 43 patients, from 39 families, mainly of European origin. Disease-causing mutations were identified in 72% of the alleles and included eight splicing, six missense, and three nonsense mutations, as well as two small insertions and two small deletions. In addition, Southern blot analysis indicated rearrangements in some alleles. Most mutations were private or occurred in two or three families, except for a missense mutation resulting in an R750W substitution. This mutation was found in 13 patients, from different European countries, and accounted for 21% of the disease alleles. Although there were clinical variations among the patients, no significant LAMAN activity could be detected in any of the fibroblast cultures. In addition, no correlation between the types of mutations and the clinical manifestations was evident.

DNA Mutational Analysis↗
PubMed1999

Relating alcohol use and mood: results from the Tromsø study.

OBJECTIVE: The interrelationships between alcohol consumption and depressed mood were studied in a population to determine if the relationships differed by sex and consumption. METHOD: Alcohol consumption and mood were surveyed at a 7-year interval by self-report (N = 8,260; 4,407 women). Frequency of intoxication was used to divide the sample into moderate and immoderate drinkers. Structural equations modeling was then applied to describe the interrelationships of drinking and mood both cross-sectionally and over time. RESULTS: Overall, self-reported drinking was stable over a 7-year period, although drinking patterns were less stable for immoderate drinkers. Drinking predicted higher levels of depressed mood among the immoderate drinkers of both sexes at follow-up. Drinking also weakly predicted depressed mood among moderately consuming men. However, among moderately consuming women dysphoric mood predicted less drinking. Depressed mood was related to higher levels of concurrent drinking among the immoderately drinking men. Among immoderately drinking women, however, concurrent depressed mood predicted more drinking. CONCLUSIONS: Generally, drinking predicted subsequent depressed mood although this pattern was reversed among moderately drinking women. Furthermore, a synchronous effects model indicated that some immoderately drinking women used alcohol as a response to emotional distress. It appears that gender and the level of consumption need to be taken into account in studies relating mood and drinking.

Adaptation, Psychological↗
PubMed1999

Self-reported seasonal variation in depression at 78 degree north. The Svalbard Study.

STUDY OBJECTIVES: To explore and compare the one year prevalence of self-reported depression in two ethnically different populations. DESIGN: A cross-sectional study of each population (1988-89 and 1993). SETTING: Norwegians living in Longyearbyen, Svalbard, and Russians living in Barentsburg and Pyramiden, Svalbard, both representing the world's two northern most regularly inhabited settlements. PARTICIPANTS: 506 Norwegians (327 men and 179 women) and 446 Russians (314 men and 132 women), all 18 years or older, living on Svalbard. MAIN RESULTS: Among Russians, the one year prevalence of self-reported depression lasting for at least 2 weeks was 26.8% for men and 44.7% for women. Corresponding figures for the Norwegians were 10.7 and 15.6%. For the period with polar night the figures were 5.5 and 6.7% for Norwegians, and 21.7 and 37.1% for Russian men and women, respectively. Depression was most common in the youngest age-group among Russians and in the oldest age-group among the Norwegians. CONCLUSION: The one year prevalence of depression was 2-3 times higher among Russians compared to Norwegians living on Svalbard. For the period with polar night, the figures were 4-5 times higher for Russians. As both populations are exposed to the same amount of daylight, seasonal depression may therefor not solely be a matter of lack of daylight. Because the Russian population came from lower latitudes than the Norwegians, we hypothesize that insufficient acclimatization after migration to the north is essential for the understanding of seasonal variation in depression.

Adolescent↗
PubMed1997

Purification of feline lysosomal alpha-mannosidase, determination of its cDNA sequence and identification of a mutation causing alpha-mannosidosis in Persian cats.

alpha-Mannosidosis is a lysosomal storage disorder that is caused by the deficiency of lysosomal alpha-mannosidase. Feline alpha-mannosidosis is a well-characterized animal model used for studying pathological and therapeutic aspects of lysosomal storage disorders. We here report the purification of feline liver lysosomal alpha-mannosidase and determination of its cDNA sequence. The active enzyme consisted of three polypeptides, with molecular masses of 72, 41 and 12 kDa, joined by non-covalent forces. The cDNA sequence of feline lysosomal alpha-mannosidase was determined from reverse transcriptase PCR products obtained from skin fibroblast mRNA. The deduced amino acid sequence contained the N-terminal sequences of the 72 and 41 kDa peptides. This indicated that the enzyme is synthesized as a single-chain precursor with a putative signal peptide of 50 amino acids followed by a polypeptide chain of 957 amino acids, which is cleaved into the three polypeptides of the mature enzyme. The deduced amino acid sequence was 81.1 and 83.2% identical with the human and bovine lysosomal alpha-mannosidases sequences respectively. A 4 bp deletion was identified in an alpha-mannosidosis-affected Persian cat by DNA sequencing of reverse transcriptase PCR products. The deletion resulted in a frame shift from codon 583 and premature termination at codon 645. No lysosomal alpha-mannosidase activity could be detected in the liver of this cat. A domestic long-haired cat expressing a milder alpha-mannosidosis phenotype than the Persian cat had a lysosomal alpha-mannosidase activity of 2% of normal. This domestic long-haired cat did not possess the 4 bp deletion, proving molecular heterogeneity for feline alpha-mannosidosis.

Amino Acid Sequence↗
PubMed1997

Genomic structure of the human lysosomal alpha-mannosidase gene (MANB).

Lysosomal alpha-mannosidase (LAMAN) (EC 3.2.1.24) is an exoglycosidase involved in the ordered degradation of N-linked oligosaccharides. Lack of LAMAN activity leads to the lysosomal storage disorder alpha-mannosidosis (MIM No. 248500). We determined the genomic organization of the human lysosomal alpha-mannosidase gene (laman; HGMW-approved symbol MANB) by using oligonucleotide primers designed from the human laman cDNA sequence as part of a PCR-based strategy. The gene spanned 21.5 kb and contained 24 exons. By primer extension analysis, the major transcription initiation sites were mapped to positions -309, -196, and -191 relative to the first in-frame ATG. No CAAT or TATA sequences could be identified within 134 bp upstream of the transcription initiation sites, but the 5' flanking region contained several GC-rich regions with putative binding sites for the transcription factors SP-1, AP-2, and ETF.

Base Sequence↗
PubMed1997

Purification of bovine lysosomal alpha-mannosidase, characterization of its gene and determination of two mutations that cause alpha-mannosidosis.

Bovine kidney lysosomal alpha-mannosidase was purified to homogeneity and the gene was cloned. The gene was organized in 24 exons that spanned 16 kb and its corresponding cDNA contained an open reading frame of 2997 bp beginning from a putative ATG start codon. The deduced amino acid sequence contained a signal peptide of 50 amino acids adjacent to a protein sequence of 949 amino acids that was cleaved into five peptides in the mature enzyme; starting with the peptide derived from the N-terminal part of this precursor, their molecular masses were 35/38 (peptide a), 11/13 (peptide b), 22 (peptide c), 38 (peptide d) and 13/15 kDa (peptide e). Variation in the degree of N-glycosylation accounts for molecular mass heterogeneities of peptides a, b and e. Peptides a, b and c were disulphide-linked. A T961-->C transition, resulting in Phe321-->Leu substitution, was identified in the cDNA of alpha-mannosidosis-affected Angus cattle. In affected Galloway cattle, a G662-->A transition that causes Arg221-->His substitution was identified. Phe321 and Arg221 are conserved among the alpha-mannosidase class-2 family, indicating that the substitutions resulted from disease-causing mutations in these breeds.

Amino Acid Sequence↗
PubMed1997

alpha-Mannosidosis: functional cloning of the lysosomal alpha-mannosidase cDNA and identification of a mutation in two affected siblings.

a-Mannosidosis (MIM 248500) is an autosomal recessive lysosomal storage disorder resulting from deficient activity of lysosomal alpha-mannosidase (LAMAN) (EC 3.2.1.24). The disease is characterized by massive intracellular accumulation of mannose-rich oligosaccharides with resulting mental retardation, hearing loss, immune deficiency and skeletal changes. We report here the purification and characterization of human placenta LAMAN. The enzyme is synthesized as a single-chain precursor which is processed into three glycopeptides of 70, 42 and 15 kDa. The 70 kDa peptide is further partially proteolysed into three more peptides that are joined by disulfide bridges. The laman cDNA sequence was assembled from overlapping fragments obtained by PCR on human fibroblast and human lung cDNA. The deduced amino acid sequence contains a putative signal peptide of 48 amino acids followed by a polypeptide sequence of 962 amino acids. Northern blot analyses revealed a single transcript of approximately 3.5 kb present in all tissues examined but at varying levels. Two affected siblings of Palestinian origin were homozygous for a mutation that causes a His-->Leu replacement at a position which is conserved among class 2 alpha-mannosidases from several species.

Amino Acid Sequence↗
PubMed1997

Modulation of disease severity of dystrophic epidermolysis bullosa by a splice site mutation in combination with a missense mutation in the COL7A1 gene.

Dystrophic epidermolysis bullosa (EBD) is a clinically heterogeneous skin disorder, characterized by abnormal anchoring fibrils (AF) and loss of dermal-epidermal adherence. EBD has been linked to the COL7A1 gene at chromosome 3p21 which encodes collagen VII, the major component of the AF. Here we investigated two unrelated EBD families with different clinical phenotypes and novel combinations of recessive and dominant COL7A1 mutations. Both families shared the same recessive heterozygous 14 bp deletion at the exon-intron 115 boundary of the COL7A1 gene. The deletion caused in-frame skipping of exon 115 and the elimination of 29 amino acid residues from the pro-alpha1(VII) polypeptide chain. As a result, procollagen VII was not converted to collagen VII and the C-terminal NC-2 propeptide which is normally removed from the procollagen VII prior to formation of the anchoring fibrils was retained in the skin. All affected individuals also carried missense mutations in exon 73 of COL7A1 which lead to different glycine-to-arginine substitutions in the triple-helical domain of collagen VII. Combination of the deletion mutation with a G2009R substitution resulted in a mild phenotype. In contrast, combination of the deletion with a G2043R substitution led to a severe phenotype. The G2043R substitution was a de novo mutation which alone caused a mild phenotype. Thus, different combinations of dominant and recessive COL7A1 mutations can modulate disease activity of EBD and alter the clinical presentation of the patients.

Adolescent↗