Alpha-synuclein: relating metals to structure, function and inhibition.

Alpha-synuclein has long been studied due to its involvement in the progression of Parkinson's disease (PD), a common neurodegenerative disorder, although a consensus on the exact function of this protein is elusive. This protein shows remarkable structural plasticity and this property is important for both correct cellular function and pathological progression of PD. Formation of intracellular oligomeric species within the substantia nigra correlates with disease progression and it has been proposed that formation of a partially folded intermediate is key to the initiation of the fibrillisation process. Many factors can influence changes in the structure of alpha-synuclein such as disease mutations and interaction with metals and neurotransmitters. High concentrations of both dopamine and metals are present in the substantia nigra making this an ideal location for both the structural alteration of alpha-synuclein and the production of toxic oxygen species. The recent proposal that alpha-synuclein is a ferrireductase is important as it can possibly catalyse the formation of such reactive species and as a result exacerbate neurodegeneration.

Randomised double-blind, placebo-controlled trial of the effects of the 'party pills' BZP/TFMPP alone and in combination with alcohol.

The objective of this study was to determine the clinical effects of party pills containing benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) when taken alone and in combination with alcohol. The study was a randomised, double-blind, placebo-controlled trial conducted in a hospital-based clinic in Wellington, New Zealand. Thirty-five volunteers who had previously used party pills containing BZP were included in this trial. Participants received one of the following four treatments: 300 mg/74 mg BZP/TFMPP and placebo, 300 mg/74 mg BZP/TFMPP and 57.6 g (6 units) alcohol, placebo and 57.6 g (6 units) alcohol and double placebo. The primary outcome variable was a measure of driving performance, the standard deviation of lateral position (SDLP) measured at 6.5 h. Secondary measures included adverse events, cardiovascular effects, psychological function and delayed effects on sleep. The study was stopped early, after 35 of the planned 64 subjects had undertaken testing, because of severe adverse events that occurred in four of 10 BZP/TFMPP-only subjects, three of seven combined BZP/TFMPP and alcohol subjects, none of the 6 placebo subjects, and none of the 12 alcohol-only subjects. The overall rate of severe adverse events (defined as causing considerable interference with usual activity and/or rated by subject as severe) in those receiving BZP/TFMPP was seven of 17 (41.2%, 95% CI 18.4-67.1). The severe events included agitation, anxiety, hallucinations, vomiting, insomnia and migraine. BZP/TFMPP significantly improved the driving performance, decreasing SDLP at -4.2 cm (95% CI -6.8 to -1.6, P = 0.002). The effect of alcohol was to increase SDLP: 2.3 cm (95% CI -0.3 to 4.9, P = 0.08). BZP/TFMPP also resulted in increased heart rate and blood pressure and in difficulty in getting to sleep. BZP/TFMPP alone or with alcohol carries a significant risk of severe adverse events when taken in similar doses to those recommended by manufacturers.

Sequence analysis and transcript identification within 1.5 MB of DNA deleted together with the NDP and MAO genes in atypical Norrie disease patients presenting with a profound phenotype.

Mutations at the Norrie disease gene locus, NDP, manifest in a broad range of defects. These range from a relatively mild, late-onset, exudative vitreoretinopathy to congenital blindness and sensorineural deafness combined, in some cases, with mental retardation. In addition, extensive deletions involving the NDP locus, located at Xp11.3, the adjacent monoamine oxidadase genes MAOA and MAOB, and additional material, result in a more severe pattern of symptoms. The phenotypes include all or some of the following; mental retardation, involuntary movements, hypertensive crises and hypogonadism. We extended an existing YAC contig to embrace the boundaries of three of the largest deletions and converted this into four PAC contigs. Computer analysis and experimental data have resulted in the identification of several putative loci, including a phosphatase inhibitor 2-like gene (dJ154.1) and a 250-bp sequence which resembles a homeobox domain (dA113.3), 1.2 Mb and 400 kb respectively from the MAO/NDP cluster. The pattern of expression of dJ154.1 suggests that it may represent an important factor contributing to the complex phenotypes of these deletion patients. Hum Mutat 17:523, 2001.

Establishing surveillance for diabetes in American Indian youth.

OBJECTIVE: To determine prevalence estimates in order to monitor diabetes, particularly type 2 diabetes, in American Indian youth. RESEARCH DESIGN AND METHODS: To explore the feasibility of developing a case definition using information from primary care records, all youth aged <20 years with an outpatient visit or hospitalization for diabetes were identified from the Billings Area Indian Health Service database in Montana and Wyoming from 1997 to 1999, and the medical records were reviewed. Classification for probable type 1 diabetes was based on age < or =5 years, weight per age < or =15th percentile at diagnosis, or positive results of islet cell antibody test. Classification for probable type 2 diabetes was based on weight per age > or =85th percentile or presence of acanthosis nigricans at diagnosis, elevated C-peptide or insulin, family history for type 2 diabetes, or use of oral hypoglycemic agents with or without insulin or absence of current treatment 1 year after diagnosis. RESULTS: A total of 52 case subjects with diabetes were identified, 3 of whom had diabetes secondary to other conditions. Of the remaining 49 case subjects, 25 (51%) were categorized as having probable type 2 diabetes, 14 (29%) as having probable type 1 diabetes, and 10 (20%) could not be categorized because of missing or negative information. Prevalence estimates for diabetes of all types, type 1 diabetes, and type 2 diabetes were 2.3, 0.6, and 1.1, respectively, per 1,000 youth aged <20 years. CONCLUSIONS: Our definitions may be useful for surveillance in primary care settings until further studies develop feasible case definitions for monitoring trends in diabetes among youth.

Preserved implicit learning on both the serial reaction time task and artificial grammar in patients with Parkinson's disease.

Thirteen nondemented patients with Parkinson's disease (PD) were compared with age-matched controls on two standard tests of implicit learning. A verbal version of the Serial Reaction Time (SRT) task was used to assess sequence learning and an artificial grammar (AG) task assessed perceptual learning. It was predicted that PD patients would show implicit learning on the AG task but not the SRT task, as motor sequence learning is thought to be reliant on the basal ganglia, which is damaged in PD. Patients with PD demonstrated implicit learning on both tasks. In light of these unexpected results the research on SRT learning in PD is reconsidered, and some possible explanations for the sometimes conflicting results of PD patient samples on the SRT task are considered. Four factors which merit further study in this regard are the degree to which the SRT task relies on overt motor responses, the effects of frontal lobe dysfunction upon implicit sequence learning, the effects of cerebellar degeneration, and the degree to which the illness itself has advanced.

Cardiovascular disease and risk factors in Montana American Indians and non-Indians.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death for both American Indian and non-Indian adults. Few published studies have compared the prevalence of CVD and related risk factors in Indians to that in non-Indians in the same geographic area. OBJECTIVE: To compare CVD and risk factors in American Indian and non-Indian populations in Montana. METHODS: Adult American Indians (n=1000) living on or near Montana's seven reservations and non-Indian (n=905) Montanans statewide were interviewed through the 1999 Behavioral Risk Factor Surveillance Survey (BRFSS). RESULTS: Indians aged > or =45 years reported a significantly higher prevalence of CVD compared to non-Indians (18% vs 10%). In persons aged 18-44 years, Indians were more likely to report hypertension (15% vs 10%), obesity (29% vs 12%), and smoking (42% vs 24%) compared to non-Indians. For persons aged > or =45 years, Indians reported higher rates of diabetes (24% vs 9%), obesity (38% vs 16%), and smoking (32% vs 13%) compared to non-Indians. Non-Indians aged > or =45 years reported having been diagnosed with high cholesterol more frequently than did Indians (32% vs 24%). CONCLUSIONS: Both Indians and non-Indians in Montana reported a substantial burden of CVD. The CVD risk patterns differ in the two populations. Prevention programs should be tailored to the risk burdens in these communities with particular emphasis on smoking cessation and the prevention of obesity.

Implicit and explicit memory in pregnant women: an analysis of data-driven and conceptually driven processes.

A study by Brindle, Brown, Brown, Griffith, and Turner (1991), reported that pregnant women showed impaired implicit memory (as measured by a stem completion task) in the presence of intact explicit memory. The present study was an attempt to replicate and extend this finding by employing a read/generate encoding manipulation across data-driven (word fragment completion and graphemic cued recall) and conceptually driven (semantic cued recall and category generation) tests. A total of 64 women (32 pregnant) were tested on both data-driven and conceptually driven tasks either directly or indirectly. No differences emerged between pregnant subjects and non-pregnant controls across tasks. Subjects experiencing their first pregnancy did report their memory in the previous 2 weeks as being considerably worse than normal.

Pharmacokinetics of fluticasone propionate inhaled via the Diskhaler and Diskus powder devices in healthy volunteers.

OBJECTIVE: The aim of these studies was to determine the absolute bioavailability in healthy volunteers of inhaled fluticasone propionate (FP) administered as a single dose via the Diskhaler and Diskus powder devices, and the pharmacokinetics of inhaled FP after repeated administration via the Diskhaler device. METHODS: In 2 of the studies, single inhaled doses of FP were administered via the Diskhaler and the Diskus powder devices, and, in the third study, repeated doses of FP were administered via the Diskhaler. In the single dose studies, 12 healthy volunteers were randomised to receive FP 1000 microg by inhalation and FP 250 microg intravenously, using a double-blind crossover design. In the repeated dose study, 24 healthy volunteers received FP 1000 microg twice daily for 7.5 days. RESULTS: Systemic exposure to FP after administration of a single 1000 microg inhaled dose of FP via the 2 powder devices was similar; the area under the plasma FP concentration-time curve (AUC) to infinite time (AUCinfinity) was 2.08 microg/L x h [95% confidence intervals (CI): 1.63-2.64] for Diskhaler and 2.49 microg/L x h (95% CI: 2.09-2.96) for Diskus. Maximum plasma FP concentration (Cmax) was 0.34 microg/L for both devices. Mean bioavailability values via the Diskhaler and Diskus were 11.9% (95% CI: 9.0-15.7%) and 16.6% (95% CI: 13.6-20.3%), respectively. No clinically significant reductions in urinary cortisol excretion were recorded in these 2 studies. After repeated administration with the Diskhaler, steady state was achieved by dose 3 (i.e. day 2) onwards. After dose 15, the AUC up to 12 hours (AUC12h) was 2.25 microg/L x h and Cmax was 0.38 microg/L. The mean steady-state to single dose accumulation ratio after twice-daily administration was 1.49 (95% CI: 1.36-1.62). CONCLUSION: The pharmacokinetics of FP administered by the 2 powder devices are similar in healthy volunteers, although systemic bioavailability was greater with the Diskus.

Systemic exposure to fluticasone propionate administered via metered-dose inhaler containing chlorofluorocarbon or hydrofluoroalkane propellant.

OBJECTIVE: The pharmacokinetic profile of a single dose of inhaled fluticasone propionate (FP) administered via a metered-dose inhaler (MDI), containing either a chlorofluorocarbon (CFC) or hydrofluoroalkane (HFA) propellant was investigated in healthy volunteers. METHODS: Two randomised, double-blind, crossover studies were conducted, each in 12 male volunteers. Both studies compared pharmacokinetic data after a single inhaled dose of FP 1000 microg from a MDI containing either CFC (CFC MDI) or HFA (HFA MDI) with a single intravenous dose of FP 250 microg. RESULTS: The maximum plasma FP concentrations after inhalation via the 2 types of MDI were almost identical (0.56 and 0.54 microg/L for CFC MDI and HFA MDI, respectively); bioavailability values of inhaled FP from the 2 MDIs were also similar (geometric mean values: 26.4% via the CFC MDI and 28.6% via the HFA MDI). Inhalation of FP via both MDI formulations produced similar reductions in urinary cortisol excretion over 12 and 24 hours postdose. CONCLUSION: The bioavailability values of FP after inhalation via a CFC MDI and an HFA MDI are similar. The 2 formulations deliver comparable amounts of FP, and systemic exposures to FP from the 2 devices, measured by urinary cortisol excretion, are not significantly different.

Bioavailability of orally administered micronised fluticasone propionate.

OBJECTIVE: The aim of this study was to determine the absolute oral bioavailability of fluticasone propionate (FP) in healthy volunteers. METHODS: A 3-period incomplete block crossover design was used. On separate occasions, 21 male volunteers received a single 250 microg intravenous dose of FP (n = 21) and twice daily oral doses of either micronised FP 0.1 mg (n = 9), 1 mg (n = 12), 10 mg (n = 11) or placebo (n = 9) for 4 days. RESULTS: FP was not measurable in the plasma after twice daily oral administration of a 0.1 mg dose. FP concentrations just above the limit of quantification could be measured in only 5 volunteers, and only at some time points, after administration of FP 1 mg twice daily. At a dose of 10 mg twice daily the absolute oral bioavailability of the drug was <1% when a liquid chromatography-mass spectrometry assay was used to assess plasma concentrations. Only oral doses of FP 10 mg twice daily, 10 times greater than the recommended maximum inhaled dose, produced any detectable change in urinary cortisol excretion. CONCLUSION: The results of this study confirm that oral absorption of FP into the systemic circulation is negligible. The swallowed portion of an inhaled dose of FP is unlikely to increase the systemic exposure to the drug, thus decreasing the likelihood of adverse systemic effects.

Implicit learning in Parkinson's disease: evidence from a verbal version of the serial reaction time task.

Evidence suggests that patients suffering from Parkinson's Disease (PD) demonstrate less sequence learning in the serial reaction time (SRT) task devised by Nissen and Bullemer (1987). One of the problems with this task is that it is motor intensive and, given the motor difficulties which characterize Parkinson's disease (e.g., tremor, impaired facility of movement, rigidity, and loss of postural reflexes), allows the possibility that patients with PD are capable of sequence learning but are simply unable to demonstrate this through a decrease in reaction time over trials. The present study examined the performance of patients with PD and healthy controls, matched for verbal fluency, on a verbal version of the SRT task where the standard button-pressing response was replaced by a spoken response. Thirteen nondementing patients with PD and 11 healthy controls were administered the SRT task. The PD group demonstrated less sequence learning than the controls and this was independent of age and severity of illness. The results add support to those studies which have found impaired sequence learning using the standard form of the SRT task.

Genetic analysis of sterile mutants in the dpy-5 unc-13 (I) genomic region of Caenorhabditis elegans.

Essential genes were identified in the 1.5-map unit dpy-5 unc-13 region of chromosome I in the Caenorhabditis elegans genome by rescuing lethal mutations using the duplication sDp2. In this paper, we report the mapping and complementation testing of lethal mutations, 45 of which identify 18 new, essential genes. This analysis brings the number of essential genes defined by the sDp2 rescue of lethal mutants to 97; 64 of these map between dpy-5 and unc-13. 61% of these essential genes are identified by more than one allele. Positioning of the mutations was done using the breakpoints of six duplications. The mutant phenotypes of 14 loci essential for fertility were characterized by Nomarski microscopy and DAPI staining. None of the mutants were rescued by wild-type male sperm. The cytological data showed that four genes produced mutants with defects in gonadogenesis. let-395. let-603, let-605 and let-610. Mutations in seven genes, let-355, let-367, let-384, let-513, let-544, let-545 and let-606, affected germ cell proliferation or gametogenesis. Mutants for the remaining three genes, let-370, let-599 and let-604, produced eggs that failed to develop or hatch. thereby acting as maternal effect lethals. We observed a nonrandom distribution of arrest phenotypes with regard to map position.

Alignment of the genetic and physical maps in the dpy-5 bli-4 (I) region of C. elegans by the serial cosmid rescue of lethal mutations.

Lethal mutations in the 0.5 map unit region between dpy-5 and bli-4 on chromosome I in Caenorhabditis elegans were serially rescued using cosmid-containing transgenic strains. All the lethal mutations analyzed came from a set of 495 EMS-induced, sDp2-rescued lethals described previously. Germline transformation with cosmid DNA was used to create 25 transgenic strains bearing heritable extrachromosomal arrays. These arrays were used as small duplications for the fine-scale mapping of essential genes, via the rescue of lethal mutations. Lethal mutations in 13 essential genes have been phenotypically rescued, allowing the alignment of the genetic and physical maps in this region. Extrachromosomal arrays were found to be transmitted 2- to 7-fold less frequently in oocytes than in hermaphrodite sperm for 12 of the 16 arrays that were examined. Three of these strains showed a subsequent 4- to 13-fold increase in array stability in oocytes. This phenomenon may be influenced by cosmid sequences. Early mitotic loss of the arrays was observed in all 17 transgenic strains examined, suggesting that loss of the array can occur at any time during development when cell divisions are occurring. As a result of this work, 13 of the essential loci positioned between dpy-5 and bli-4 are anchored to the physical map, thereby providing links between the physical and genetic maps on average every 85 kb.

Indirect learning of event sequences: the effects of divided attention and stimulus continuity.

In a serial reaction time (SRT) task, the learning curve is sleeper when the stimuli are presented in a repeating sequential manner rather than in random order (Nissen & Bullemer, 1987). This is true even when subjects report being unaware of the presence of the repeating sequence. The present study examines the nature of this learning under conditions designed to reduce attentional resources and to disrupt the continuity of stimuli. In the first three experiments, subjects were trained in the SRT task, with or without the addition of a secondary tone counting task, and with repeating or non-repeating sequences. The results suggest that some sequence learning occurred despite the presence of a secondary task. Experiment 4 examined the extent of sequence learning when the inter-stimulus interval was varied between trials. The overall results suggest that despite reduced attentional allocation and discontinuous stimulus presentation, some sequence learning occurs. This result supports other work suggesting a dissociation between learning when measured explicitly, and when assessed through performance indicators.

Cognitive function and quality of life in end-stage renal failure.

The Sickness Impact Profile (SIP) and the Wechsler Memory Scale--Revised (WMS-R) were administered to a small sample of end-stage renal failure patients. The memory test successfully discriminated between patients who were rated by their nurses to be well adjusted or poorly adjusted to dialysis treatment. It is concluded that this instrument may be useful in investigating cognitive function in this patient population.

Mutations in the bli-4 (I) locus of Caenorhabditis elegans disrupt both adult cuticle and early larval development.

The bli-4 (I) gene of Caenorhabditis elegans had been previously defined by a single recessive mutation, e937, which disrupts the structure of adult-stage cuticle causing the formation of fluid-filled separations of the cuticle layers, or blisters. We report the identification of 11 new alleles of bli-4, all early larval lethals, including an allele induced by transposon mutagenesis. Nine of the lethal alleles failed to complement the blistered phenotype of e937; two alleles, s90 and h754, complement e937. The complementing alleles arrested development somewhat later than the noncomplementing alleles, which blocked just prior to hatching. We conclude that bli-4 is a complex locus with an essential function late in embryogenesis. We investigated the blistered phenotype of e937 through interactions with other mutations that alter worm morphology or cuticle structure. Recessive and dominant epistasis of several dumpy mutations over the blistered phenotype was observed. Using two heterochronic mutations that alter the developmental stage at which adult cuticle is expressed, we observed that adult worms that lack an adult-stage cuticle could not express blisters. However, late larval worms that expressed the adult cuticle did not express blisters either. It seems likely that the presence of the adult cuticle is necessary, but not sufficient, for blister expression. Blistering resulting from e937 is more severe in trans to null alleles, indicating that e937 is hypomorphic. We postulate that the adult-specific blistering is due to an altered or reduced function of bli-4 gene product in the adult cuticle.(ABSTRACT TRUNCATED AT 250 WORDS)