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V Ulrich

Publications and source records attributed to V Ulrich.

At least 19 recordsLinked to original sources
PubMed2005

Observation of resonant interatomic coulombic decay in Ne clusters.

We have measured the electron spectra of Ne clusters after excitation with photon energies around the 2s inner valence threshold. At two photon energies below threshold, a resonantly enhanced surplus of low kinetic-energy electrons is observed. The kinetic energy of the peak does not vary with the photon energy and is slightly larger than the transition energy of Interatomic Coulombic Decay (ICD) above threshold. This leads us to assume that an ICD-like process is present. In analogy to the Auger and the resonant Auger decay this new phenomenon is termed resonant ICD.

Journal Article↗
PubMed2001

Is the genetic liability in multifactorial disorders higher in concordant than discordant monozygotic twin pairs? A population-based family twin study of migraine without aura.

Migraine without aura (MO) is a multifactorial disorder. Expression of a disorder with multifactorial inheritance depends on the genetic liability and on environmental factors. A high liability is reflected by a high frequency of affected relatives. We have previously shown that monozygotic (MZ) twin pairs have a significant higher concordance of MO than dizygotic twin pairs. The incomplete concordance among MZ twin pairs may be due to a lower genetic liability among discordant than concordant MZ twin pairs. The present study analysed the genetic liability in MZ twin pairs concordant and discordant for MO by the population-relative risk of MO among parents and siblings. The twin pairs were from the population-based Danish Twin Register. First-degree relatives of 29 concordant and 34 discordant MZ twin pairs were blindly telephone interviewed by a physician. The participation rate of the eligible first-degree relatives was 96%. The population-relative risk of MO among parents and siblings was 2.73 (2.39-3.06) in concordant and 2.37 (2.03-2.71) in discordant MZ twin pairs. The relative risk of MO was significantly higher in female first-degree relatives of concordant than of discordant MZ male and female twin pairs. An opposite effect was observed in male first-degree relatives, although this was not significant for male first-degree relatives of female MZ twin pairs. The present study found no statistically significant difference in genetic liability to MO among concordant and discordant MZ twin pairs. However, a difference in genetic liability among MZ and DZ twin pairs is anticipated to be small. Thus, it may be possible to show the effect in a larger study population or by investigating a more frequent trait than MO.

Adolescent↗
PubMed2000

[The significance of genetic and environmental factors for migraine with aura. A genetic epidemiologic study of Danish twins].

We studied the genetic and environmental influence on migraine with aura (MA) by analysing a twin population. The twin sample consisted of 2,026 monozygotic (MZ) pairs and 3,334 same-gender dizygotic (DZ) pairs recruited from the population-based Danish Twin Register. A total of 211 pairs were identified, of whom 77 were MZ and 134 were DZ. The pairwise concordance rate was significantly higher in MZ-than in DZ-pairs, i.e. 34% and 12%, respectively, emphasizing the importance of genetic factors in MA. However, environmental factors are also important, as the pair wise concordance rate was less than 100% in MZ-pairs. Similarly, the recurrence risk of MA was 50% in MZ- and 21% in DZ-pairs which was a significant difference. In non-twin siblings, the recurrence risk of MA is 27%, which is similar to the recurrence risk in DZ-pairs. This indicates that MA is not developed due to specific environmental factors shared by the twins.

Adult↗
PubMed2000

Possible risk factors and precipitants for migraine with aura in discordant twin-pairs: a population-based study.

The aim of the present study was to detect possible risk factors in migraine with aura (MA) by analysis of discordant twin-pairs. In a recent population-based twin study we established that environmental factors account for approximately 50% of the variation in liability to MA. A cohort of 5,360 same-gender twin-pairs from the general population was screened for migraine. All twin-pairs with possible migraine were interviewed by a physician. A questionnaire provided information about living conditions and lifestyle. Of the 169 discordant twin-pairs 51 were monozygotic and 118 were dizygotic twin-pairs. Several putative risk factors-schooling, education, marital status, smoking status and alcohol consumption-showed no association with MA. The presence of migraine without aura or tension-type headache did not increase the risk of MA. Stress and mental tension, and bright light precipitated attacks of MA in, respectively, 44% and 28% of the twins.

Alcohol Drinking↗
PubMed1999

The relative role of genetic and environmental factors in migraine without aura.

OBJECTIVE: To clarify the relative role of genetic and environmental factors in the etiology of migraine without aura (MO). METHODS: The study population consisted of 5,360 twins, 1,013 monozygotic (MZ) and 1,667 same-gender dizygotic (DZ) twin pairs, from the population-based Danish Twin Registry. A total of 87% completed a simple validated questionnaire screening for migraine. All twin pairs, in whom at least one twin had self-reported migraine or severe headache with accompanying symptoms, were interviewed via telephone by a physician. Ninety percent of the eligible twins were interviewed. Probandwise concordance rates and correlations in liability were calculated, and structural equation model-fitting analyses were applied to quantitate the relative role of genetic and environmental factors in the etiology of MO. RESULTS: The probandwise concordance rate was higher in MZ than DZ twin pairs (0.43 versus 0.31; 95% CI, 0.36 to 0.49 versus 0.26 to 0.36). The correlation in liability was higher in MZ than in DZ twin pairs (0.62 versus 0.41; 95% CI, 0.50 to 0.74 versus 0.29 to 0.53). Structural equation model fitting indicated a highly significant genetic component, because a model with both genetic and environmental components fitted significantly better than a model with only environmental components. The best fitting model implied that the liability to MO resulted from additive genetic effects (61%; 95% CI, 49 to 71%)) and individual-specific environmental effects (39%; 95% CI, 29 to 51%). CONCLUSION: This study indicates that genetic factors play a role in the etiology of migraine without aura. The genetic variability is additive, with a negligible contribution of nonadditive genetic effects. The genetic contributions were similar in men and women despite a higher prevalence in women. Environmental factors are equally important and these factors are individual to the migraineurs.

Adolescent↗
PubMed1999

Evidence of a genetic factor in migraine with aura: a population-based Danish twin study.

We studied the genetic influence on cause of migraine with aura (MA) by analyzing a twin population. The twin sample consisted of 2,026 monozygotic (MZ) twins and 3,334 same-sex dizygotic (DZ) twins, born from 1953 to 1960, from the population-based New Danish Twin Register. A validated questionnaire was used to screen for migraine, the response rate being 87%, and similar among MZ and DZ twins. All twin pairs with at least 1 twin with possible MA were interviewed by a physician experienced in headache diagnoses. The answers from the questionnaire as well as the zygosity of the twins were blinded for the interviewer. A total of 211 twin pairs were identified, of whom 77 pairs were MZ and 134 pairs were DZ. The lifetime prevalence of MA was 7% and with a male-to-female ratio of 1:1.1. The pairwise concordance rates were significantly higher in MZ (34%) than in DZ twin pairs (12%), emphasizing the importance of genetic factors in MA. However, environmental factors are also important, as the pairwise concordance rate was less than 100% in MZ twin pairs. The recurrence risk of MA was 50% in MZ and 21% in DZ twin pairs. In nontwin siblings, the recurrence risk of MA is 27%, which is similar to the recurrence risk in DZ twins. This indicates that MA is not developed due to specific environmental factors shared by the twins.

Adult↗
PubMed1999

Migraine without aura: a population-based twin study.

To investigate the importance of genetic and environmental factors to the etiology of migraine without aura and to compare the symptomatology of migraine without aura in monozygotic and dizygotic twins, 2,680 twin pairs were recruited from the population-based Danish Twin Registry. Monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs, where at least one twin had self-reported migraine or self-reported severe headache with accompanying symptoms, were telephone interviewed by a physician. The participation rate in the telephone interview was 90%. The pairwise concordance rate was significantly higher in MZ than in DZ twin pairs (28% vs 18%). The probandwise concordance rate was 40% (95% CI, 33-48%) in MZ and 28% (95% CI, 23-33%) in DZ twin pairs. The pairwise concordance rates for the different pain characteristics and accompanying symptoms were not significantly different in MZ and DZ twin pairs. However, comparing all of the pairwise concordance rates of pain characteristics and accompanying symptoms together, MZ twin pairs were significantly more concordant than DZ twin pairs. Our data demonstrate a significant genetic factor in migraine without aura. The size of this factor is modest and the demonstration of susceptibility genes is predicted to be laborious and difficult.

Diseases in Twins↗
PubMed1999

Glyceryl trinitrate induces attacks of migraine without aura in sufferers of migraine with aura.

Migraine with aura and migraine without aura have the same pain phase, thus indicating that migraine with aura and migraine without aura share a common pathway of nociception. In recent years, increasing evidence has suggested that the messenger molecule nitric oxide (NO) is involved in pain mechanisms of migraine without aura. In order to clarify whether the same is true for migraine with aura, in the present study we examined the headache response to intravenous infusion of glyceryl trinitrate (GTN) (0.5 microg/kg/min for 20 min) in 12 sufferers of migraine with aura. The specific aim was to elucidate whether an aura and/or an attack of migraine without aura could be induced. Fourteen healthy subjects served as controls. Aura symptoms were not elicited in any subject. Headache was more severe in migraineurs than in the controls during and immediately after GTN infusion (p=0.037) as well as during the following 11 h (p = 0.008). In the controls, the GTN-induced headache gradually disappeared, whereas in migraineurs peak headache intensity occurred at a mean time of 240 min post-infusion. At this time the induced headache in 6 of 12 migraineurs fulfilled the diagnostic criteria for migraine without aura of the International Headache Society. The results therefore suggest that NO is involved in the pain mechanisms of migraine with aura. Since cortical spreading depression has been shown to liberate NO in animals, this finding may help our understanding of the coupling between cortical spreading depression and headache in migraine with aura.

Adult↗
PubMed1999

The prevalence and characteristics of migraine in twins from the general population.

We examined whether prevalence, age at onset, and cessation of migraine without aura and migraine with aura are different among twins and singletons. The study population was recruited from the population-based New Danish Twin Register and comprised 2026 monozygotic and 3334 same-sex dizygotic twins born during 1953 to 1960. A simple questionnaire was used to screen for migraine. Twin pairs with at least one twin with possible migraine were interviewed by telephone by two physicians. A total of 1136 twin pairs were included in the telephone interviews. The criteria of the International Headache Society were used for diagnosis. The questionnaire response rate was 87%, and the telephone interview participation rate was 90%. Of the 715 migraineurs, 498 had migraine without aura, 264 had migraine with aura, and 47 had both migraine with and without aura. The lifetime prevalence, age at onset, and cessation of migraine with and without aura did not differ in monozygotic and dizygotic twins. Males and females had a lifetime prevalence of migraine without aura of 7% and 19%, respectively. The female preponderance of migraine without aura was first apparent after aged 14 years; this may be related to an influence of female hormones. The lifetime prevalence of migraine with aura was 7% in males and 8% in females. The observed and expected number of those with both migraine with and without aura was not significantly different, suggesting that migraine without aura and migraine with aura are distinct types of migraine. Males with migraine without aura had a significantly lower mean age at onset than females with migraine without aura (16.5 years versus 21.5 years), while males and females with migraine with aura had similar ages at onset (20.8 years versus 21.8 years). About 20% of the twins had ceased having attacks of migraine with or without aura. More males than females with onset of migraine without aura before aged 15 years had ceased having attacks. The prevalence of migraine without aura and migraine with aura in twins was similar to the prevalence in the general population. Being a twin did not affect age at onset or cessation of migraine. Previous observations on differences of migraine without aura and migraine with aura regarding gender was confirmed.

Adult↗
PubMed1999

The inheritance of migraine with aura estimated by means of structural equation modelling.

Studies of migraine with aura (MA) have shown familial aggregation of the disorder, which cannot be explained by simple mendelian inheritance. The interest in a genetic basis for the disorder has increased after identification of three genetic loci for familial hemiplegic migraine (FHM), which is a rare subtype of MA with autosomal dominant inheritance. Both genetic and environmental factors seem to be important in the expression of MA. To elucidate the molecular pathogenesis of MA, knowledge of the relative role of genetic and environmental factors is essential. Twin studies are a classic way to analyse this. We applied structural equation modelling on MA with twin data obtained from a population based twin register in order to evaluate the effects of genes and environment. The correlation in liability of MA was 0.68 in monozygotic (MZ) and 0.22 in dizygotic (DZ) twin pairs, indicating a high degree of genetic determination in the total variance of liability. The best fitting model combined additive genetic effects and environmental effects that were not shared by the twins. The estimate of heritability was 0.65 and similar in males and females.

Female↗
PubMed1998

Altered allelic distributions of the serotonin transporter gene in migraine without aura and migraine with aura.

Allelic variation of the human serotonin transporter gene (HSERT), a highly plausible candidate gene for susceptibility to migraine, was investigated in 266 individuals with migraine, including 173 having migraine without aura (MO), 94 having migraine with aura (MA), 18 with co-occurrence of MO and MA, plus 133 unaffected controls. The distribution of a polymorphism with different forms of a variable tandem number repeat (VNTR) in intron 2 were compared. The MO group had an over-representation of genotypes with two twelve repeat alleles (STin2.12) and a reduction of genotypes containing one ten repeat (STin2.10) compared to controls. The MA group showed a similar pattern, but also a trend towards an increase in genotypes containing the nine repeat allele of the VNTR (STin2.9). Genotypes containing this allele were found in 6.4% of the MA group compared to 2.3% of controls. The group with co-occurrence of MO and MA had a significantly different pattern of overall allele frequency distribution from controls, reflecting a reduction in genotypes containing the STin2.10 allele and a shift both to STin2.9 carriers and to STin2.12 homozygosity. These results support the view that susceptibility to MO and MA has a genetic component, that these disorders are distinct, and that genetic susceptibility may in some cases be associated with a locus at or near the serotonin transporter gene.

Adult↗
PubMed1998

Nitric oxide synthase inhibition: a new principle in the treatment of migraine attacks.

Glyceryl trinitrate, an exogenous nitric oxide (NO) donor, and histamine, which causes NO formation in vascular endothelium, have been shown to trigger migraine attacks. However, it remains uncertain whether NO is involved in the subsequent phase of migraine attacks. To answer this question we studied the effect of L-NGmethylarginine hydrochloride (546C88), a NO-synthase inhibitor, on spontaneous migraine attacks. In a double-blind study design, 18 patients with migraine without aura randomly received 546C88 (6 mg/kg) or placebo (5% dextrose) i.v. given over 15 min for a single migraine attack (546C88:placebo, 15:3). Furthermore, 11 placebo-treated patients from previous double-blind trials with almost identical design were added to the placebo group in the statistical evaluation. Two hours after the infusion, 10 of 15 L-NGmethylarginine hydrochloride-treated patients experienced headache relief compared to 2 of 14 placebo-treated patients (p = 0.01). Symptoms such as phono- and photophobia were also significantly improved. A similar trend for nausea was not significant. We conclude that NO may be involved in the pain mechanisms throughout the course of spontaneous migraine attacks.

Adolescent↗
PubMed1997

Analysis of 31 families with an apparently autosomal-dominant transmission of migraine with aura in the nuclear family.

We analyzed 31 families selected for an apparently autosomal-dominant mode of inheritance of migraine with aura (MA) in the nuclear family. The nuclear families were expanded with first- and second-degree relatives. All interviews were made by physicians experienced in headache diagnoses. The criteria of the International Headache Society were used. The population relative risk among children in nuclear families was similar to the estimated population relative risk of MA assuming an autosomal-dominant mode of inheritance. The population relative risk tended to decrease among first-degree relatives outside nuclear families and further among second-degree relatives. Both first- and second-degree relatives outside the nuclear families had a statistically significant lower risk of MA than expected. Thus, autosomal-dominant inheritance with or without reduced penetrance was unlikely. Autosomal-recessive inheritance was unlikely because of the unequal sex distribution. Other modes of inheritance were considered as well. Mitochondrial and X-linked inheritance were excluded because of paternal transmission. The female preponderance was too low to explain sex-influenced inheritance. We conclude that MA most likely has a multifactorial inheritance even in high-risk families with MA.

Adolescent↗
PubMed1996

A comparison of tension-type headache in migraineurs and in non-migraineurs: a population-based study.

The prevalence, sex-ratio and clinical characteristics of tension-type headache were analyzed in 4000 people from the general population. The one-year-period prevalence of tension-type headache was not significantly different in people with migraine without aura (83%), in people with migraine with aura (75%) and in people who had never had migraine (76%). The male/female ratio varied from 1:1.19 to 1:1.23 and was not significantly different in the three subgroups. Tension-type headache was significantly more frequent within the last year and lasted longer in migraineurs than in people who had never had migraine. The pain characteristics and accompanying symptoms were very similar in the three subgroups. Tension-type headache was often precipitated by stress, mental tension and tiredness. Only migraineurs had episodes of tension-type headache precipitated by alcohol, over-matured cheese, chocolate and physical activity. We conclude that tension-type headache and migraine are separate disorders and not part of a continuum of headache disorders. However, migraine may aggravate and precipitate tension-type headache possibly due to convergence of various noxious peripheral input into the trigeminal nucleus.

Adult↗
PubMed1996

Healthcare reform and expenditure on drugs. The German situation.

Germany is in a period of transition with regard to healthcare reform. The number and intensity of cost control interventions increased during the last decade in an attempt to contain healthcare expenditure. The German legislature has implemented long term macroeconomic measures such as contribution rate stability and global budgeting. The mid-term goal is to reduce the structural deficits of the current system. This paper argues that reference prices, introduced in the 1989 Healthcare Reform Act, did not produce the expected savings. An analysis of the effects of the 1993 Healthcare Structure Act on pharmaceutical expenditure is also presented. Compared with the implementation of the reference price system, the introduction of global budgeting in 1993 has had a more effective and lasting cost-containment impact. The paper concludes with a review of the main aspects of the current reform discussion.

Costs and Cost Analysis↗
PubMed1983

Comparisons of liver chromatin proteins and template activities in parental and heterotic rats during postweaned development.

Electrophoretic profiles of acid-extractable proteins from Holtzman rat liver chromatin display four minor and five major histone bands through certain stages of postweaned development but are qualitatively different from the chromatin protein profiles previously reported during postweaned development for the Fisher 344 rat strain and the F344 X Holtzman heterotic progeny [Tallman, G., et al. (1979). Biochem, Genet. 17:185]. The protein profiles from the heterotic progeny do not reflect and are not combinations of the profiles from the parental strains. Levels of in vitro transcription with Escherichia coli RNA polymerase of total chromatin and of acid-extracted chromatin from Holtzman rat liver tissue fluctuate in an age-specific manner during postweaned development and are higher than previously published levels determined for the Fisher and F344 X H strains during the same developmental period [Tallman, G., et al. (1978). J. Hered. 69:282]. The degrees of stimulation in the transcription assays resulting from the acid treatment vary with the age of the animal but are similar for the maternal Holtzman and hybrid strains. These studies suggest that regulation of heterotic growth may involve dominant, or maternal genetic influences.

Animals↗