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Biomedical subjects

C Hublin

Publications and source records attributed to C Hublin.

29 records · Page 2Linked to original sources
PubMed1994

Twin studies in narcolepsy.

The genetic basis of narcolepsy is reflected by the strong association to human leukocyte antigen DR2 (most specifically to DQB1-0602) and the occasional familial occurrence, with several modes of transmission. At present, 12 monozygotic pairs with at least one affected twin have been reported. Of the three pairs considered concordant, the only well-documented pair is DR2 negative. Of the nine discordant pairs five are well documented, and all of these are DR2 positive. We performed a questionnaire study using a validated measure of narcoleptic symptoms (the Ullanlinna narcolepsy scale or UNS). The questionnaire was sent to 2,191 monozygotic twin pairs included in the Finnish Twin Cohort. In 225 pairs neither of the twins responded. In 1,550 pairs both twins responded, but in the answers of 228 pairs there were some missing data concerning the UNS items. Not a single case suggestive of narcolepsy was found. Narcolepsy in monozygotic twins is very rare. These facts support the hypothesis of a multifactorial etiology with a strong influence of nongenetic environmental factors.

Adult↗
PubMed1994

Epidemiology of narcolepsy.

The prevalence of narcolepsy is usually presented at about 50/100,000. There are, however, marked differences of about 2,500-fold between the lowest and the highest reported prevalence. This discrepancy is at least partly explained by differences in the study populations and methods. There are, however, no earlier population-based epidemiological studies with polygraphically confirmed diagnoses. We studied the occurrence of symptoms resembling the two main manifestations of narcolepsy, i.e. abnormal sleep tendency and emotion-associated muscular weakness, in an adult twin cohort (n = 16,179) with a questionnaire. A total of 3.2% met the minimal diagnostic criteria of the International Classification of Sleep Disorders for narcolepsy. Eleven questionnaire items assessing the main manifestations of narcolepsy formed a measure called the Ullanlinna Narcolepsy Scale (UNS), which has been validated. The UNS score was calculated for 11,354 subjects. Those (n = 75) having a UNS score equal or higher than the lowest value in a narcolepsy patient group were studied. Thirty-one of them (fulfilling also the minimal diagnostic criteria) were interviewed, and those suspected of having narcolepsy (n = 5) were evaluated in the sleep laboratory. In three subjects the narcolepsy diagnosis was verified (all dizygotic, nonfamilial and human leukocyte antigen DR2/DQB-0602 positive), giving a prevalence of 0.026% in the adult Finnish (Caucasian) population.

Adult↗
PubMed1994

The Ullanlinna Narcolepsy Scale: validation of a measure of symptoms in the narcoleptic syndrome.

The Ullanlinna Narcolepsy Scale (UNS) is a simple questionnaire-based method used to measure the symptoms of the narcoleptic syndrome. The 11-item scale (range 0-44) assesses the two main features of the narcoleptic syndrome, the abnormal sleeping tendency and cataplexy. The UNS sum score reliably distinguishes patients with the narcoleptic syndrome from patients with sleep apnoea, multiple sclerosis, and epilepsy. The mean score in patients with the narcoleptic syndrome was 27.3 (95% confidence limits 24.4-33.1); the sleep apnoea group with a mean score of 9.6 (95% confidence limits 7.2-12.0) came closest to this. Validation data were also selected from a large survey of non-institutionalized adults in Finland including groups with insomnia, excessive daytime sleepiness, sleep deprivation, sciatica, alcohol abuse, and high scores on a depression scale and on a scale of neurovegetative symptoms. With the lowest UNS score in the narcoleptic syndrome group (= 14) as the cutpoint, the sensitivity is 100% and the specificity is 98.8% in the subjects studied. The accurate assessment of the symptoms of the narcoleptic syndrome in a format suitable for questionnaire studies is essential.

Journal Article↗
PubMed1994

Autonomic nervous system function in narcolepsy.

A disturbance of the autonomic nervous system (ANS) in narcolepsy has been suggested, based on abnormalities on pupillometry, ejaculatory and cardiovascular function. The ANS function was studied by measuring the variation in the heart rate and blood pressure during provocations, using the following tests: deep breathing test, Valsalva test and Orthostatic test for heart rate reactivity measurements, and Orthostatic test for blood pressure control. Each test session gave seven variables, and these were compared to age-adjusted reference values in healthy normals. In 22 unmedicated narcoleptics (median age 50.5 y, range 18-70 y) the results did not differ from these. Seventeen of the patients were included in a controlled stimulant medication trial (selegiline 10-40 mg daily), and they showed no significant changes in the ANS variables except for a dose-dependent rise in heart ratio (placebo 1.32+/-1-0.13 and 40 mg 1.14+/-0.05; mean+/-SD) and a decrease in systolic blood pressure (placebo 5.8+/-9.7 and 40 mg 30.1+/-21.5 mmHg) on Orthostatic test. Although blood pressure decreases >/=30 mmHg (maximally 72 mmHg) occurred in 9 patients, they were asymptomatic. These changes are considered primarily to reflect the known characteristic of monoamine oxidase inhibitors to cause postural hypotonia. Abnormalities using these methods were not found, thus supporting the view that cardiovascular reflex abnormalities would be characteristic of narcolepsy.

Journal Article↗
PubMed1994

Dopamine D2-receptors in human narcolepsy: a SPECT study with 123I-IBZM.

Increased dopamine D2 receptor binding in basal ganglia has been reported in human narcolepsy. These studies have been based on post-mortem material of 8 patients, most of them also medicated for narcolepsy. We studied six narcoleptics without stimulant or anticataplectic medication. The patients had an unambiguous history of cataplexy, and they were also studied polygraphically. Single photon emission computed tomography (SPECT) imaging was performed. The D2 receptor density was determined by using 123I-iodobenzamide (IBZM). The control subjects were 8 unmedicated Parkinson patients with one-sided (hemiparkinsonian) clinical symptoms. The D2 receptor density in them is known to be normal or somewhat increased compared to healthy normals. The striatum/frontal D2 activity ratio was 1.331 +/- 0.084 (with phantom study correction 2.101 +/- 0.300) in the narcoleptic patients, and in the parkinsonian controls 1.321 +/- 0.052 (2.067 +/- 0.185) for the asymptomatic side and 1.335 +/- 0.025 (2.117 +/- 0.090) for the symptomatic side (i.e. contralateral to the side with the clinical extrapyramidal signs). There was no statistical difference between the groups or between the symptomatic and asymptomatic side in the Parkinson patients. Thus, our results differ from the earlier post-mortem studies.

Adult↗
PubMed1994

Selegiline in the treatment of narcolepsy.

We treated 17 narcolepsy patients in a placebo-controlled, double-blind, crossover trial with 10-, 20-, 30-, and 40-mg daily doses of selegiline, a monoamine oxidase inhibitor widely used in Parkinson's disease. There was a dose-dependent as well as a statistically and clinically significant improvement in narcoleptic symptoms and polygraphic measures. At 40 mg, there was a 36% reduction in the number of daytime sleep episodes and a 34% reduction in their duration (compared with placebo, mean values). The number of excessive sleepiness episodes decreased by 43%, and the duration decreased by 47%. The number of cataplectic attacks was reduced by 89%. On the multiple sleep latency test, the REM sleep latency increased from 5.0 to 13.3 minutes, and the number of sleep-onset REM periods decreased from 3.1 to 0.6. Sleep (S1) latency was not changed. No intolerable adverse events occurred. The effective dose range was 20 to 40 mg, requiring a low-tyramine diet, which was easy to maintain. In conclusion, selegiline alleviates both main symptoms of narcolepsy--the abnormal sleep tendency and cataplexy. Thus, treatment with selegiline makes it possible to avoid polypharmacy and to use a potent stimulant without known addiction risk.

Adolescent↗
PubMed1991

Misuse of zopiclone and convulsions during withdrawal.

It has been documented that benzodiazepines have the potential to cause dependence and withdrawal reactions, including convulsions. However, the available data concerning zopiclone, a nonbenzodiazepine hypnotic, are insufficient. The present study describes the case of a 36-year-old man who repeatedly misused zopiclone, in daily doses of 60-90 mg. Furthermore, the patient suffered from convulsion on two occasions following abrupt withdrawal of zopiclone. The concomitant use of alcohol, trimipramine, and promazine may have contributed to the development of convulsions. It is concluded that zopiclone may cause problems associated with misuse and withdrawal reactions similar to those of benzodiazepines.

Adult↗
PubMed1991

Familial narcolepsy in Finland.

Five patients with narcolepsy-cataplexy (aged 31-69, mean age at onset 15 years) and their 47 relatives were examined. They were interviewed in detail, all patients and 16 relatives (including all symptomatic cases) were examined neurologically and a multiple sleep latency test and HLA-typing were done. One case of narcolepsy and two cases of idiopathic hypersomnia were identified. All the other 45 relatives were symptom-free. The observed rate of familial cases (1/5 for narcolepsy and 2/5 for idiopathic hypersomnia) corresponds the results of other recent studies.

Adult↗