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Attention deficit hyperactivity disorder (ADHD) is a common psychiatric disorder in childhood and adolescence and in a considerable number of patients it persists into adulthood. A network of brain regions have been shown to be abnormal in ADHD. In the present study we used magnetic resonance volumetry to investigate a possible role of the orbitofrontal cortex (OFC). Eight never medicated male patients fulfilling diagnostic criteria for ADHD and 17 male healthy controls were investigated. There was a significant reduction of the volume of the left OFC in patients with ADHD. It remains unknown whether small volumes are a primary deficit or a result of dysfunctional activation during childhood in terms of a residual deficit or a specific type of adult outcome of the disease.

The present study evaluates dose-dependent behavioral effects of acutely or subacutely administered single doses of vigabatrin (gamma-vinyl gamma-aminobutyric acid, gamma-vinyl GABA, CAS 60643-86-9) in audiogenic sensitive rats, in correlation with whole brain GABA metabolism. There was a discrepancy in timing between behaviorally observed maximal antiepileptic protection (4 h after i.p. administration of gamma-vinyl GABA) and on the other hand maximal inhibition of GABA-transaminase activity and maximal increase of whole brain GABA content (24 h after i.p. administration of gamma-vinyl GABA). This suggests that the antiepileptic properties of gamma-vinyl GABA not only depend on GABA-ergic neurotransmission. A possible explanation is a gamma-vinyl GABA-induced decrease of excitatory amino acids or increased glycine concentrations in the brain.

N1-Acetylspermine has been postulated to be an intermediate in the conversion of spermine to spermidine. This compound, together with N1-acetylspermidine has now been detected in the liver of mice which were pretreated with tetrachloromethane. The following methods were used for the identification of N1-acetylspermine: (a) High-pressure liquid-chromatography of the non-derivatized amines on a reversed-phase column, using octane sulfonate for ion-pairing. (b) Thin-layer chromatography of the dansyl derivatives. (c) Mass spectrometry of the dansyl derivatives. Both chromatographic methods allowed the quantitative estimation of N1-acetylspermine and N1-acetylspermidine in the liver of tetrachloromethane-treated animals.

Chironomids, of which approximately 10,000 species exist, are reported to cause severe immediate type allergic diseases in man. In the present study, immunological cross-reactivity between 14 chironomid species from different continents was proven by RAST inhibition, double immunodiffusion and a new allergoprint technique, based upon PAGE separation of insect crude extracts. Using isolated chironomid haemoglobins and sera of sensitized persons, as well as rabbit antibodies against larval crude extract or against the haemoglobin fraction of Chironomus thummi, it could be proven that cross-reactivity derives at least predominantly from haemoglobin components with common antigenic determinants in the different species.

Hemodynamic properties of medroxalol (MDL), a new alpha-and-beta adrenoceptor antagonistic drug, were studied in eight pentobarbital-anesthetized (open chest) dogs. MDL was injected in three doses (1.5, 3.0 and 9.0 mg/kg i.v.) at one hour intervals. A control group (n = 5) received three successive vehicle injections at the same time intervals. Heart rate, systolic and diastolic arterial pressure, cardiac output and stroke volume (using an intrathoracic flowmeter), and peripheral resistance were recorded 45 min before the first injection and 15 min after each administration. Isoproterenol (ISP) and neosynephrine (NSP) dose-response curves were recorded before the first dose and after each injection in both group. Log-linear regression analyses were used to estimate the ISP chronotropic dose 25 (DC 25) and the ISP barotropic dose 30 (DB 30). The results show that medroxalol possesses beta-adrenoreceptor antagonistic properties which are 35 times greater than its alpha-antagonistic properties. Beta-blockade was evidenced by bradycardia and increase in DC 25, beginning at the first dose used. Alpha-blockade was not significant at that first dose and therefore cannot alone explain the strong hypotension observed. All these effects were related to the plasma-concentration of MDL.

A high-pressure-liquid-chromatographic method suitable for the separation and sensitive detection of putreanine and isoputreanine is described. This method allowed us to study the formation of the metabolites of the oxidative deamination of spermidine and N1-acetylspermidine. Administration of spermidine trishydrochloride to mice causes a time-dependent accumulation of putreanine and N-(3-aminopropyl)pyrrolidin-2-one in various organs. The latter compound yields isoputreanine by hydrolysis. It can be assumed that the analogous lactam. N-(3-acetamidopropyl)pyrrolidin-2-one is formed from N1-acetylspermidine, since hydrolysis of tissue extracts of N1-acetylspermidine-treated mice produced isoputreanine. No putreanine is formed under these conditions. Pretreatment of the animals with 25 mg of aminoguanidine sulphate/kg body wt. completely inhibits the formation of putreanine and of the respective isoputreanine precursor from spermidine and N1-acetylspermidine. This suggests a role for a diamine oxidase-like enzyme in the oxidative deamination of spermidine and N1-acetylspermidine.