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Heikki Rantala

Publications and source records attributed to Heikki Rantala.

10 recordsLinked to original sources
PubMed2006

Disappearance of middle ear effusion in acute otitis media monitored daily with tympanometry.

BACKGROUND: Disappearance of middle ear effusion is one of the most important outcomes in the treatment of acute otitis media (AOM). AIM: To evaluate the duration of effusion in AOM treated by antimicrobials and to find factors influencing it. METHODS: Parents of 90 children with AOM monitored daily the disappearance of effusion with tympanometry. The children were randomly allocated to be treated with either oral amoxicillin or cefuroxime-axetil for 10 d. Daily monitoring lasted for 14 d or until the tympanogram was normal (curve A or C) in both ears. Pneumatic otoscopy was carried out every 2 wk. RESULTS: Normal tympanograms were obtained after a median time of 7.5 d (range 1-58 d) among 75 successfully monitored patients. In two-thirds (69%) of them, effusion resolved in 14 d. The median duration of effusion did not differ significantly between the two treatment groups (8 vs 7 days, p=0.7). The children who had unilateral AOM cured more rapidly than those with bilateral AOM (5 vs 19 d, p<0.001). In logistic regression analysis adjusted for age, bilaterality explained treatment failure at 2 wk with an odds ratio of 28.1 (95% CI 4.6-169.5, p<0.001). CONCLUSION: The choice of antimicrobials did not influence the duration of middle ear effusion, which was much shorter than had been thought previously. Children with unilateral AOM were cured much more quickly than those with bilateral AOM.

Acoustic Impedance Tests↗
PubMed2005

Sequence analysis of nuclear genes encoding functionally important complex I subunits in children with encephalomyopathy.

Complex I has a vital role in the energy production of the cell, and the clinical spectrum of complex I deficiency varies from severe lactic acidosis in infants to muscle weakness in adults. It has been estimated that the cause of complex I deficiency, especially in children, is often a mutation in the nuclear-encoded genes and, more rarely, in the genes encoded by mitochondrial DNA. We sequenced nine complex I subunit coding genes, NDUFAB1, NDUFS1, NDUFS2, NDUFS3, NDUFS4, NDUFS7, NDUFS8, NDUFV1 and NDUFV2, in 13 children with defined complex I deficiency. Two novel substitutions were found: a synonymous replacement 201A>T in NDUFV2 and a non-synonymous base exchange 52C>T in NDUFS8. The 52C>T substitution produced the replacement Arg18Cys in the leading peptide of the TYKY subunit. This novel missense mutation was found as a heterozygote in one patient and her mother, but not among 202 healthy controls nor among 107 children with undefined encephalomyopathy. Bioinformatic analyses suggested that Arg18Cys could lead to marked changes in the physicochemical properties of the mitochondrial-targeting peptide of TYKY, but we could not see changes in the assembly or activity of complex I or in the transcription of NDUFS8 in the fibroblasts of our patient. We suggest that Arg18Cys in the leading peptide of the TYKY subunit is not solely pathogenic, and that other genetic factors contribute to the disease-causing potential of this mutation.

Alleles↗
PubMed2004

A novel mutation of the fumarase gene in a family with autosomal recessive fumarase deficiency.

Fumarase hydratase (FH) deficiency is a rare familial disorder of the tricarboxylic acid cycle which is characterized by severe neurological impairment in early childhood. Several autosomal recessive mutations in the fumarate hydratase gene have been identified as a cause of the lack of fumarase activity in affected individuals. We describe a novel mutation in nucleotide 1127A>C of the fumarase cDNA which changes glutamine 376 to proline in the vicinity of the catalytic site and explains the loss of FH function. Two homozygous carriers of this mutation suffered from severe encephalopthy and died at a young age. Molecular modeling of FH structure shows that the mutation Gln376Pro in the second half of the fumarase sequence disrupts the structure of the active site. Analysis of the FH mutation and the mutant enzyme variant described here provides an explanation for the mechanism of FH deficiency at the molecular level and paves the way for the analysis of other dysfunctional FH variants.

Amino Acid Sequence↗
PubMed2004

Nasal sumatriptan is effective in treatment of migraine attacks in children: A randomized trial.

OBJECTIVE: To investigate the efficacy of nasal sumatriptan in migraine attacks of children and adolescents. METHODS: A double-blind, placebo-controlled, two-way crossover trial was conducted in three hospital outpatient departments, with 8 to 17 year olds diagnosed with migraine serving as subjects (International Headache Society 1988). A single dose of sumatriptan nasal spray and a matching placebo were administered at home during two attacks. The sumatriptan dose was 10 mg for a body weight of 20 to 39 kg and 20 mg for those with a body weight of >/==" BORDER="0">40 kg. The primary efficacy endpoint was headache relief by two grades on a 5-grade face scale at 2 hours. RESULTS: Eighty-three patients used both treatments and 11 only the first. At 2 hours, the primary endpoint was reached nearly twice as often after sumatriptan (n = 53/83; 64%) as after placebo (n = 32/83; 39%) (p = 0.003). Already at 1 hour, headache relief was seen more often after sumatriptan (n = 42/83; 51%) than after placebo (n = 24/83; 29%) (p = 0.014). The difference was even more obvious in patients who received the 20-mg dose as well as in the intention-to-treat analyses (n = 94). Other endpoints, including child's preference and using rescue medication, also favored sumatriptan. The most common adverse effect was a bad taste after sumatriptan, reported in 29% (n = 26/90) of the attacks. No serious adverse effects were observed. CONCLUSION: Nasal sumatriptan is an effective and well-tolerated treatment for migraine attacks in children over 8 years of age.

Administration, Intranasal↗
PubMed2004

Associated medical disorders and disabilities in children with autistic disorder: a population-based study.

A population-based survey was conducted among 152,732 Finnish children and adolescents aged under 16 years and living in northern Finland. Diagnoses and associated medical conditions were derived from the hospital and institutional records of this area. One hundred and eighty-seven children with DSM-IV autistic disorder were identified. Associated medical disorders or associated disorders of known or suspected genetic origin were found in 12.3 percent, including tuberous sclerosis, Down syndrome, fragile X syndrome, Klinefelter syndrome, XYY syndrome, chromosome 17 deletion, chromosome 46, XX, dup(8) (p) and mitochondriopathy. Other associated medical disorders identified were epilepsy, hydrocephalus, foetal alcohol syndrome and cerebral palsy. Hearing impairments were found in 8.6 percent and severe impairment of vision in 3.7 percent of the individuals with autistic disorder. Medical disorders seem to have a special impact on the genesis of autistic disorder and need to be thoroughly examined in each child with autistic disorder.

Adolescent↗
PubMed2004

Molecular epidemiology of childhood mitochondrial encephalomyopathies in a Finnish population: sequence analysis of entire mtDNA of 17 children reveals heteroplasmic mutations in tRNAArg, tRNAGlu, and tRNALeu(UUR) genes.

OBJECTIVES: Many heteroplasmic point mutations in tRNA genes of mitochondrial DNA (mtDNA) have been associated with human diseases. We recently reported on a prospective 7-year study in which we enrolled 116 consecutive children with undefined encephalomyopathy. Seventeen of them were found to have both a defect in the mitochondrial respiratory chain and abnormal ultrastructure of muscle mitochondria, suggesting a clinically probable mitochondrial encephalopathy. METHODS: We determined the frequency of mtDNA mutations in these 17 children by analyzing the entire sequence of mtDNA by conformation-sensitive gel electrophoresis and sequencing. RESULTS: Three heteroplasmic tRNA mutations that were considered to be pathogenic were detected. Two of the mutations were novel transitions, 10438A>G in the tRNA(Arg) gene and 14696A>G in the tRNA(Glu) gene, whereas the third one was 3243A>G, the common MELAS mutation. The mutant load was very high in the blood and skeletal muscle of the patients and markedly lower in the blood of asymptomatic maternal relatives. The 10438A>G mutation changes the nucleotide flanking the anticodon, whereas 14696A>G changes a nucleotide in the stem of the pseudouridine loop, creating a novel base pair and reducing the wobble. CONCLUSIONS: Our results emphasize that the analysis of the entire sequence of mtDNA is worthwhile in the diagnostic evaluation of patients with clinically probable mitochondrial encephalomyopathy. The frequency of pathogenic mtDNA mutations was found to be 18% among children with biochemically and histologically defined mitochondrial disease, suggesting that the likelihood of nuclear DNA mutations in such a group is several times higher than that of mtDNA mutations.

Base Sequence↗
PubMed2003

A mutation in mitochondrial DNA-encoded cytochrome c oxidase II gene in a child with Alpers-Huttenlocher-like disease.

OBJECTIVE: Cytochrome c oxidase (COX) deficiency has been demonstrated in some patients with Alpers-Huttenlocher disease, but no genetic background has been identified. Our objective was to determine the molecular defect underlying the mitochondrial respiratory chain deficiency in a child with Alpers-Huttenlocher-like progressive cerebrohepatic disease. METHODS: The entire coding region of mitochondrial DNA was analyzed by conformation-sensitive gel electrophoresis and sequencing. Biochemical and morphologic investigations were performed on tissue biopsy material, including oximetric and spectrophotometric analyses of oxidative phosphorylation, histochemistry, and electron microscopy. RESULTS: Postmortem histologic examination revealed a marked loss of neurons in the olivary nuclei and a spongy change in the calcarine cortex, fatty infiltration and micronodular cirrhosis of the liver, and atrophic ovaries. A novel heteroplasmic 7706G>A mutation was found in the COX II gene. The median degree of the mutant heteroplasmy was 90% in 5 tissues examined but was lower in the blood of asymptomatic maternal relatives. The distribution of the mutant heteroplasmy was skewed to the left in single muscle fibers of the proband and her mother. The 7706G>A mutation converts a hydrophobic alanine in a conserved transmembrane segment to hydrophilic threonine. CONCLUSIONS: The 7706G>A mutation is pathogenic and may lead to impaired dioxygen transfer to the active site of COX. The clinical phenotype of this patient resembled that in Alpers-Huttenlocher disease, suggesting that analysis of mitochondrial DNA is worthwhile in patients with a progressive cerebrohepatic disease.

Brain↗
PubMed2002

Visual field constriction in 91 Finnish children treated with vigabatrin.

PURPOSE: To study the prevalence and features of visual field constrictions (VFCs) associated with vigabatrin (VGB) in children. METHODS: A systematic collection of all children with any history of VGB treatment in fifteen Finnish neuropediatric units was performed, and children were included after being able to cooperate reliably in repeated visual field tests by Goldmann kinetic perimetry. This inclusion criterion yielded 91 children (45 boys; 46 girls) between ages 5.6 and 17.9 years. Visual field extent <70 degrees in the temporal meridian was considered abnormal VFC. RESULTS: There was a notable variation in visual field extents between successive test sessions and between different individuals. VFCs <70 degrees were found in repeated test sessions in 17 (18.7%) of 91 children. There was no difference in the ages at the study, the ages at the beginning of treatment, the total duration of the treatment, general cognitive performance, or neuroradiologic findings between the patients with normal visual fields and those with VFC, but the patients with VFC had received a higher total dose of VGB. In linear regression analysis, there were statistically significant inverse correlations between the temporal extent of the visual fields and the total dose and the duration of VGB treatment. The shortest duration of VGB treatment associated with VFC was 15 months, and the lowest total dose 914 g. CONCLUSIONS: Because of a wide variation in normal visual-field test results in children, the prevalence figures of VFCs are highly dependent on the definition of normality. Although our results confirm the previous findings that VFC may occur in children treated with VGB, our study points out the need to reevaluate critically any suspected VFC to avoid misdiagnosis. Nevertheless, our study suggests that the prevalence of VFC may be lower in children than in adults, and that the cumulative dose of VGB or length of VGB therapy may add to the personal predisposition for developing VFC.

Adolescent↗