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E Nikoskelainen

Publications and source records attributed to E Nikoskelainen.

At least 37 records · Page 2Linked to original sources
PubMed1993

The spectrum of mitochondrial DNA mutations in families with Leber hereditary optic neuroretinopathy.

The mitochondrial complex I genes were sequenced in seven Leber hereditary optic neuroretinopathy (LHON) families without the ND4/11,778 and ND1/3460 mutations. Four replacement mutations restricted only to LHON families were found, one in the ND1 gene at nt 4025, and three in the ND5 gene at nt 12,811, 13,637, and 13,967. The mutations did not change evolutionarily conserved amino acids suggesting that they are not primary LHON mutations in these families. They may be considered as secondary LHON mutations serving as exacerbating factors in an appropriate genetic background. A complex III mutation, cyt b/15,257, has been suggested to be one of the primary mutations causing LHON. Its presence was determined for 23 Finnish LHON families, and it was detected in two families harboring the ND4/11,778 mutation. Similarly, complex IV mutation COI/7444 was screened in Finnish LHON families, and it was found in one family carrying the ND1/3460 mutation.

Amino Acids↗
PubMed1991

Electron transfer properties of NADH:ubiquinone reductase in the ND1/3460 and the ND4/11778 mutations of the Leber hereditary optic neuroretinopathy (LHON).

We report the electron transfer properties of the NADH:ubiquinone oxidoreductase complex of the respiratory chain (Complex I) in mitochondria of cells derived from LHON patients with two different mutations in mitochondrial DNA (mtDNA). The mutations occur in the mtDNA genes coding for the ND1 and ND4 subunits of Complex I. The ND1/3460 mutation exhibits 80% reduction in rotenone-sensitive and ubiquinone-dependent electron transfer activity, whereas the proximal NADH dehydrogenase activity of the Complex is unaffected. This is in accordance with the proposal that the ND1 subunit interacts with rotenone and ubiquinone. In contrast, the ND4/11778 mutation had no effect on electron transfer activity of the Complex in inner mitochondrial membrane preparations; also Km for NADH and NADH dehydrogenase activity were unaffected. However, in isolated mitochondria with the ND4 mutation, the rate of oxidation of NAD-linked substrates, but not of succinate, was significantly decreased. This suggests that the ND4 subunit might be involved in specific aggregation of NADH-dependent dehydrogenases and Complex I, which may result in fast ('solid state') electron transfer from the former to the latter.

DNA, Mitochondrial↗
PubMed1990

DXS26 (HU16) is located in Xq21.1.

We have localized a single-copy DNA probe, HU16 (locus DXS26), to Xq21.1. The probe was isolated from a human-mouse hybrid X;13 library and mapped with human-mouse hybrids containing different portions of the human X chromosome and DNA from male patients with different X-chromosomal deletions. The following order of loci is proposed: Xcen-(DXS72,DXS169)-(DXS232,DSX26)-DXS1 21-DXS233-DXS165-TCD-DXS95-DXYS1-Xqter. HU16 will be useful in the study of the putative genes that reside in Xq21 and whose defects lead to deafness and mental retardation.

Animals↗
PubMed1988

Does sporadic Leber's disease exist?

This study gives some illustrative case reports of the difficulties in the diagnosis of Leber's hereditary optic neuroretinopathy. It underlies the importance of careful family history and search for peripapillary microangiopathy in the maternal relatives of patients suspected to suffer from Leber's disease. The article casts doubt on the existence of so-called sporadic Leber's disease.

Adult↗
PubMed1986

Familial olivopontocerebellar atrophy with macular degeneration: a separate entity among the olivopontocerebellar atrophies.

A family with hereditary, neuropathologically confirmed olivopontocerebellar atrophy (OPCA) associated with macular degeneration is described. The mode of inheritance was autosomal dominant. The first symptom was insidious, progressive visual loss caused by macular degeneration. Another early sign was slow saccades. Some years after the visual symptoms, gradually progressing cerebellar dysfunction and pyramidal signs developed. Computed tomography of the brain indicated cerebellar and pontine atrophy. Finally the patients were blind, due to a severe chorioretinal atrophy, and disabled because af motor dysfunction. The present study, together with a review of other reported families with OPCA associated with macular degeneration, suggests that this disorder is a specific and clinically recognizable subtype of OPCA.

Adult↗
PubMed1985

Fundus findings in Leber's hereditary optic neuroretinopathy.

The acute stage of Leber's hereditary optic neuritis is characterized by dilated disc arterioles accompanied, in some cases, by superficial peripapillary hemorrhages. Decreased vision caused by centrocecal scotoma is accompanied by slow and deficient capillary filling in the papillomacular bundle and arteriovenous shunting in the upper and lower vascular arcades. These and other vascular changes disappear in the more advanced stages (optic atrophy) of the disease.

Acute Disease↗
PubMed1985

The clinical findings in Leber's hereditary optic neuroretinopathy. Leber's disease.

Leber's disease is a hereditary condition primarily affecting young men. The mechanism of inheritance is unknown. Increased tortuosity and capillary microangiopathy in the peripapillary capillary bed occur in varying degrees in asymptomatic persons in families with Leber's disease. These vascular abnormalities signify an increased risk of developing the acute form of the disease. Progressive microangiopathy is a threatening sign during the presymptomatic stage. In the acute and atrophic stages of Leber's disease striking neurovascular changes take place in the fundus of the eye involved. The ophthalmoscopic observations and nerve function studies in the asymptomatic, presymptomatic and acute stages suggest that Leber's disease starts as a vascular disease. The neuropathy appears later, around the time that vision begins to fail. Both eyes are involved but at varying intervals. At the end stage the patient has bilaterally finger counting vision and a large centrocecal scotoma caused by severe optic atrophy. Examinations of other persons in families with Leber's disease have shown that subclinical and mild forms of the disease also exist. Neurological signs and symptoms can occasionally occur. Cardiac abnormalities such as pre-excitation syndrome have been reported in Leber's disease. The aetiology and precipitating factors and effective treatment to prevent blindness in Leber's disease remain unsolved questions.

Adolescent↗