Development of a novel fluorine-18 labeled deuterated fluororasagiline ([(18)F]fluororasagiline-D2) radioligand for PET studies of monoamino oxidase B (MAO-B).

The objective of this study was to synthesize and evaluate a novel fluorine-18 labeled deuterium substituted analogue of rasagiline (9, [(18)F]fluororasagiline-D2) as a potential PET radioligand for studies of monoamine oxidase B (MAO-B). The precursor compound (6) and reference standard (7) were synthesized in multi-step syntheses. Radiolabeling of 9 was accomplished by a two-step synthesis, compromising a nucleophilic substitution followed by hydrolysis of the sulfamidate group. The incorporation radiochemical yield from fluorine-18 fluoride was higher than 30%, the radiochemical purity was >99% and the specific radioactivity was >160GBq/µmol at the time of administration. In vitro compound 7 inhibited the MAO-B activity with an IC50 of 173.0±13.6nM. The MAO-A activity was inhibited with an IC50 of 9.9±1.1µM. The fluorine-18 version 9 was characterized in the cynomolgus monkey brain where a high brain uptake was found (275% SUV at 4min). There was a higher uptake in the striatum and thalamus compared to the cortex and cerebellum. A pronounced blocking effect (50% decrease) was observed in the specific brain regions after administration of l-deprenyl (0.5mg/kg) 30min prior to the administration of 9. Radiometabolite studies demonstrated 40% of unchanged radioligand at 90min post injection. An efficient radiolabeling of 9 was successfully established and in the monkey brain 9 binds to MAO-B rich regions and its binding is blocked by the selective MAO-B compound l-deprenyl. The radioligand 9 is a potential candidate for human PET studies.

Parathyroid surgical failures with misleading falls of intraoperative parathyroid hormone levels.

According to earlier reports, a decrease below 50% of baseline of intraoperative PTH levels measured 5 min after resection of the parathyroid adenoma predicts a cure of hyperparathyroidism. To reveal previously unrecognized pitfalls of intraoperative PTH measurements, we reviewed surgical failures in our series of parathyroidectomies combined with intraoperative PTH sampling. PTH measurements were performed in 251 patients with primary hyperparathyroidism (PHPT) between November 1999 and December 2002. PHPT due to parathyroid hyperplasia were found in 8 cases, double parathyroid adenomas in 6 cases, parathyroid carcinoma in 1 case and single parathyroid adenomas in 236 cases, all confirmed by histological examination. Of the 236 cases of single adenomas, initial surgery failed to cure PHPT in 4 patients. In 3 patients a false-positive decrease of intraoperative PTH (from 269 to 40 pg/ml, from 211 to 27 pg/ml, and from 140 to 59 pg/ml) was observed, whereas in the fourth patient a true-negative decrease of intraoperative PTH (from 758 to 401 pg/ml) was mistakenly interpreted as indication for a cure of PHPT. In each of the 4 patients in whom initial surgery failed the intervention included thyroid surgery and reoperative parathyroid surgery resulted in a permanent cure of PHPT. These observations support the possibility that thyroid surgery may compromise the blood supply of parathyroid adenomas resulting in a misleading drop of intraoperative PTH levels. Therefore, a careful evaluation of intraoperative PTH levels and, perhaps, other intraoperative aids such as histological evaluation of frozen sections are recommended when parathyroid surgery is combined with simultaneous thyroid intervention.

Identification of SCAN dimerization domains in four gene families.

Zinc-finger transcription factors are often accompanied by modular sequence motifs such as the Kruppel-associated box (KRAB) and the SCAN domain. The KRAB domain mediates transcriptional repression while the SCAN domain mediates selective protein dimerization. The hypoalphalipoproteinemia susceptibility gene ZNF202 encodes a SCAN box and a KRAB domain followed by eight Cys2-His2 zinc-finger motifs. In order to identify the existence of genes which encode proteins of structural homology to ZNF202, a mouse lambda library was screened with a human ZNF202 cDNA probe. The isolated cDNA clones represented three SCAN-domain-encoding gene families. We purified three novel cDNAs that encode a SCAN-KRAB-(Cys2-His2)x domain alignment and one cDNA that encodes a SCAN-(Cys2-His2)x domain alignment. In addition, we identified one cDNA sequence with a predicted protein sequence containing a KRAB-SCAN-KRAB-(Cys2-His2)x domain alignment. Therefore, when combined with the recently discovered family of isolated SCAN-domain-encoding genes, four SCAN domain gene families can be distinguished. The consensus sequences for the murine SCAN and KRAB domains are highly conserved within the mammalian phylogenetic tree which may be useful in elucidating the biological function of these protein modules and the crucial residues responsible for their binding specificity.

Fragile X mice develop sensory hyperreactivity to auditory stimuli.

Fragile X syndrome is the most prevalent cause of mental retardation. It is usually caused by the transcriptional inactivation of the FMR-1 gene. Although the cognitive defect is the most recognized symptom of fragile X syndrome, patients also show behavioral problems such as hyperarousal, hyperactivity, autism, aggression, anxiety and increased sensitivity to sensory stimuli. Here we investigated whether fragile X mice (fmr-1 gene knockout mice) exhibit abnormal sensitivity to sensory stimuli. First, hyperreactivity of fragile X mice to auditory stimulus was indicated in the prepulse inhibition paradigm. A moderately intense prepulse tone, that suppresses startle response to a strong auditory stimulus, elicited a significantly stronger effect in fragile X than in control mice. Second, sensory hyperreactivity of fragile X mice was demonstrated by a high seizure susceptibility to auditory stimulation. Selective induction of c-Fos, an early-immediate gene product, indicated that seizures involve auditory brainstem and thalamic nuclei. Audiogenic seizures were not due to a general increase in brain excitability because three different chemical convulsants (kainic acid, bicuculline and pentylenetetrazole) elicited similar effects in fragile X and wild-type mice. These data are consistent with the increased responsiveness of fragile X patients to auditory stimuli. The auditory hypersensitivity suggests an abnormal processing in the auditory system of fragile X mice, which could provide a useful model to study the molecular and cellular changes underlying fragile X syndrome.

The role of induced contrast in images obtained using the environmental scanning electron microscope.

Generation of contrast in images obtained using the environmental scanning electron microscope (ESEM) is explained by interpretation of images acquired using the gaseous secondary electron detector (GSED), ion current, and the Everhart-Thornley detector. We present a previously unreported contrast component in GSED and ion current images attributed to signal induction by changes in the concentration of positive ions in the ESEM chamber during image acquisition. Changes in positive ion concentration are caused by changes in electron emission from the sample during image acquisition and by a discrepancy between the drift velocities of negative and positive charge carriers in the imaging gas. The proposed signal generation mechanism is used to explain contrast reversal in images produced using the GSED and ion current signals and accounts for discrepancies in contrast observed, under some conditions, in these types of images. Combined with existing models of signal generation in the ESEM, the proposed model provides a basis for correct interpretation of ESEM images.

No teratogenic effect after clotrimazole therapy during pregnancy.

We evaluated the potential teratogenic effects of vaginal and/or topical administration of clotrimazole in the large population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1992). The dataset included 18,515 case pregnancies and 32,804 control pregnancies; 7.1% of case and 7.7% of control women used clotrimazole during pregnancy. Clotrimazole use was not clearly associated with an increase in the total (fetal + birth) prevalence of any congenital abnormality group. There was, however, a suggestion that clotrimazole use was associated with a decrease in the prevalence of undescended testis (prevalence odds ratio = 0.72; 95% confidence interval = 0.54-0.95).

Population-based case control study of folic acid supplementation during pregnancy.

Previous studies have demonstrated that periconceptional folic acid/multivitamin supplementation reduced the occurrence of neural tube defects. A case control analysis has been conducted in the dataset of the Hungarian Case Control Surveillance of Congenital Abnormalities, 1980-1991. In the study period, 54.9% of 30,663 pregnant women who had healthy babies (negative control group) were supplemented with high doses (in general 2 x 3 mg) of folic acid per day. In those 17,300 pregnant women who had offspring with congenital abnormalities, the rate of folic acid supplementation was 50.4%. Exposure histories: preconceptional, I, II, III, and IV-IX postconceptional months were determined by record reviews and questionnaire assessment. The case control pair analysis showed a significant protection after folic acid supplementation during the critical period of cardiovascular defects, neural tube defects, cleft lip with or without cleft palate and posterior cleft palate.

Amoxicillin/clavulanic acid vs cefetamet pivoxil in the treatment of acute exacerbation of chronic bronchitis (AECB) in adults.

In this open comparative and prospective study 180 adults of either sex were randomised to treatment with either amoxicillin/clavulanic acid (AMC) 500/125mg tid or cefetamet pivoxil (CAT) 500mg bid for 7 days. Demographic data and assessable findings were similar in both groups. Clinical outcomes of 169 assessable patients showed high efficacy of both drugs: 92% with AMC and 96% with CAT. Bacteriological response rates were equivalent in 141 evaluable cases: 84% vs. 89%, respectively. Baseline susceptibility testing (DIN) revealed a notable number of Haemophilus species either intermediately susceptible or resistant to AMC. Gastrointestinal disorders predominated among the adverse events with diarrhea occurring nearly twice as often in the AMC group. CAT is an effective and safe alternative option in the treatment of AECB in adults. The advantage of CAT is its enhanced activity against gram-negative bacteria. It is well tolerated.

[Possibilities of antioxidant therapy in the prevention of side effects of amiodarone]. / Az antioxidáns therapia lehetöségei az amiodaron mellékhatások megelözésében, illetve kivédésében.

The authors demonstrated the generation of a very reactive phenyl radical from amiodarone in a reducing molecular environment by pulse radiolysis study. The various antioxidants are probably not capable of preventing the generation of phenyl radical, as well as to protect against its damaging effects on the neighboring molecules. Electron microscopic studies from lung tissue of in vivo treated rats showed that the simultaneous Silibinin (a flavonoid type antioxidant) treatment with amiodarone decreased significantly the lysosomal phospholipoidosis induced by amiodarone compared with the amiodarone treated group, but it didn't prevent entirely the accumulation of lysosomal phospholipids. The in vitro lysosomal beta-glucuronidase enzyme release measured from the liver tissue of in vivo treated rats increased significantly on amiodarone treatment, the antioxidants used (Silibinin, and the dihydroquinoline type MTDQ-DA) didn't exert any favorable effect. The authors discuss in details the possible relationships between free radical reactions and lysosomal phospholipoidosis.

Plant small nuclear RNAs. Nucleolar U3 snRNA is present in plants: partial characterization.

Nuclei, isolated from a number of plant species by either of two independent, newly developed methods, regularly contained a common set of low-molecular-mass RNAs. Partial characterization of these RNAs, based on cell fractionation, polyacrylamide gel electrophoretic and chemical sequencing techniques, as well as comparison with literature data, revealed that, in addition to tRNA, 5S RNA and 5.8S RNA, plant nuclei contain two families of low-molecular-mass RNAs, that are counterparts of vertebrate U1 and U5 RNAs respectively, and three individual low-molecular-mass RNA species. One of these may be related to vertebrate U6 RNA. The two others are true eukaryotic U2 and U3 RNAs, respectively, on the basis of the following lines of evidence obtained from analyses of broad bean nuclear RNAs. The 3'-end portion (121 nucleotides sequenced) of broad bean U2 RNA shows a nearly perfect sequence homology with that of authentic pea U2 RNA. Broad bean U3 RNA is localized in the nucleolus and its 3'-end portion (164 nucleotides sequenced) (a) shows sequence homology with that of both rat U3 RNA (48%) and Dictyostelium D2 RNA (39%), (b) has a secondary structure which fits perfectly that proposed for both rat U3 RNA and Dictyostelium D2 RNA, and (c) contains the specific sequence which, in a model based on the primary structure of rat U3 RNA, is supposed to be involved in the processing of eukaryotic 32S pre-ribosomal RNA. This is the first report on the occurrence in plants of nucleolar U3 RNA.

Preparative separation of intact incomplete and empty adenovirus type 2 particles.

Complete adenovirus type 2 virions containing the whole genome were resistant to while empty capsids lacking DNA were breakable at a separation procedure involving customary CsCl gradient centrifugation. A purification method was developed using CsCl density gradient centrifugation in 5% glycerol which retained the integrity of incomplete particles as well as empty capsids. This procedure enabled to study the biological and physicochemical properties of different adenovirus type 2 particles.