Closed-loop glycaemic control using an implantable artificial pancreas in diabetic domestic pig (Sus scrofa domesticus).

The performance of a completely implantable peritoneal artificial pancreas (AP) has been demonstrated in principle in a live diabetic domestic pig. The device consists of a smart glucose-sensitive gel that forms a gateway to an insulin reservoir and is designed to both sense glucose and deliver insulin in the peritoneal cavity. It can be refilled with insulin via subcutaneous ports and surgery was developed to insert the AP. Diabetes was induced with streptozotocin (STZ), the device filled with insulin (Humulin(®) R U-500) in situ and the animal observed for several weeks, during which time there was normal access to food and water and several oral glucose challenges. Blood glucose (BG) levels were brought down from >30 mmol/L (540 mg/dL) to non-fasted values between 7 and 13 mmol/L (126-234 mg/dL) about five days after filling the device. Glucose challenge responses improved ultimately so that, starting at 10 mmol/L (180 mg/dL), the BG peak was 18 mmol/L (324 mg/dL) and fell to 7 mmol/L (126 mg/dL) after 30 min, contrasting with intravenous attempts. The reservoir solution was removed after 8 days of blood glucose levels during which they had been increasingly better controlled. A rapid return to diabetic BG levels (30 mmol/L) occurred only after a further 24 days implying some insulin had remained in the device after removal of the reservoir solution. Thus, the closed loop system appeared to have particular influence on the basal and bolus needs for the 8 days in which the reservoir solution was in place and substantial impact for a further 3 weeks. No additional insulin manual adjustment was given during this period.

Phase II/III randomized trial of TCH346 in patients with ALS.

BACKGROUND: TCH346 exerts antiapoptotic effects by binding to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and blocking the apoptotic pathway in which GAPDH is involved. Apoptosis is considered to be a key pathogenic mechanism in neurodegenerative diseases including ALS. METHODS: Patients were randomly assigned in a double-blind fashion to receive either placebo or one of four doses of TCH346 (1.0, 2.5, 7.5, or 15 mg/day) administered orally once daily for at least 24 weeks. The primary outcome measure was the rate of change in the revised ALS functional rating scale (ALSFRS-R). The trial design included a 16-week lead-in phase to determine each patient's rate of disease progression. The between treatment comparison was adjusted for the individual pretreatment rates of progression. The study was powered to detect a 25% reduction in the rate of decline of the ALSFRS-R as compared with placebo. Secondary outcome measures included survival, pulmonary function, and manual muscle testing (MMT). RESULTS: Five hundred ninety-one patients were enrolled at 42 sites in Europe and North America. There were no differences in baseline variables. There were no significant differences between placebo and active treatment groups in the mean rate of decline of the ALSFRS-R or in the secondary outcome measures (survival, pulmonary function, and MMT). CONCLUSION: The trial revealed no evidence of a beneficial effect of TCH346 on disease progression in patients with ALS.

Characterisation of hydrogel gel swelling by molecular exclusion.

A facile method for the characterization of hydrogel swelling is described which is based on the determination of changes in the liquid phase concentration of an excluded tracer as gel swells in a constant volume system. The utility of this approach is demonstrated with two responsive hydrogel preparations, one where swelling is influenced by system pH, the other by changes in specific solute concentration.

An open-label evaluation of the tolerability and safety of Stalevo (carbidopa, levodopa and entacapone) in Parkinson's disease patients experiencing wearing-off.

OBJECTIVES: To evaluate the tolerability, safety and efficacy of Stalevo (carbidopa, levodopa and entacapone) in Parkinson's disease (PD). BACKGROUND: Levodopa provides the most effective symptom control for the treatment of Parkinson's disease (PD). However, its long-term use is limited by the development of motor complications such as wearing-off. Catechol-O-methyltransferase (COMT) inhibitors such as entacapone extend the plasma half-life of levodopa and reduce 'off' time. Stalevo is a new levodopa product that combines carbidopa, levodopa and entacapone in one tablet. Clinical studies have not been reported with this compound. DESIGN METHODS: An open-label, multi-center US trial evaluated 169 consecutive PD patients experiencing end-of-dose wearing-off, with (n = 39) and without (n = 130) mild dyskinesia. Patients were switched from immediate-release carbidopa/levodopa to Stalevo and were treated for four weeks. Assessments included tolerability measures, adverse events profile, the disease-specific quality of life instrument PDQ-39, UPDRS parts II, III, and question 39 and investigator and patient global clinical assessments. RESULTS: 14 subjects (8%) discontinued treatment with Stalevo, of which 12 (7%) were due to adverse events. 11/130 (8.5%) subjects developed new onset dyskinesia and 17/39 (43.6%) of patients with existing dyskinesia reported a worsening in their dyskinesia. However, this was managed by a change in dose in 21.4% of patients and in another 10.7% dyskinesias resolved without any need for dose adjustment. Other side effects were infrequent and mild, the most common being nausea (12.4%) dizziness (6.5%) and somnolence (6.5%). Stalevo treatment resulted in significant improvements in PDQ-39 and UPDRS (II + III) scores (p < 0.001). Assessment of 'off' time demonstrated a reduction in off time in 32% of patients, compared with an increase in 7% of patients. Improvements were noted by both investigator (68.1%) and patient (68.6%) assessments. CONCLUSIONS: Switching PD patients experiencing wearing-off from carbidopa/levodopa therapy to Stalevo was safe, well tolerated and resulted in clinical improvement.

Double-blind, placebo-controlled study of entacapone in levodopa-treated patients with stable Parkinson disease.

BACKGROUND: The catechol O-methyltransferase inhibitor entacapone acts by extending the elimination half-life of levodopa and is currently approved as an adjunct to levodopa for the treatment of patients with Parkinson disease (PD) with motor fluctuations. OBJECTIVE: To determine if the addition of entacapone administration provides benefit to levodopa-treated PD patients who have a stable response to levodopa and do not experience motor complications. DESIGN: Prospective, double-blind, placebo-controlled trial. SETTING: Outpatient multicenter study. PATIENTS: Female and male patients 30 years or older with idiopathic PD receiving stable doses of levodopa or carbidopa with or without other dopaminergic therapies and who did not experience motor fluctuations were eligible for the study. MAIN OUTCOME MEASURES: Parkinsonian function and quality of life. RESULTS: The addition of entacapone did not improve motor scores on the Unified Parkinson's Disease Rating Scale in levodopa-treated PD patients who did not experience motor fluctuations. The mean +/- SE adjusted change between baseline and final treatment visit was -0.9 +/- 0.35 in the entacapone group and -0.8 +/- 0.35 in the placebo group (P = .83). Significant improvement with entacapone treatment was detected in several quality-of-life measures, including the Parkinson Disease Questionnaire 39, the 36-item Short-Form Health Survey, the Parkinson's Symptom Inventory, and investigator and subject Clinical Global Assessments. The drug was well tolerated by patients in this population. CONCLUSIONS: The catechol O-methyltransferase inhibitor entacapone, used as an adjunct to levodopa in PD patients who do not experience motor fluctuations, does not improve Unified Parkinson's Disease Rating Scale motor scores but does improve a variety of quality-of-life measures.

NAD-sensitive hydrogel for the release of macromolecules.

A hydrogel membrane containing immobilized ligands and receptors was synthesized and investigated for the controlled diffusion of test proteins (cytochrome C and hemoglobin). Both Cibacron blue (ligand) and lysozyme (receptor) were covalently linked to dextran molecules that were subsequently crosslinked to form a gel. The resulting stable hydrogels contained both covalent and affinity crosslinks such that their intrinsic porosities were sensitive to competitive displacers of the affinity interaction between lysozyme and Cibacron blue. Transport experiments in a twin chamber diffusion cell showed that as NAD was added to the donor side, the dissociation of the binding sites between the Cibacron blue and the lysozyme led to an increase in protein diffusion through the hydrogel. The results showed that addition of NAD caused a saturable concentration-dependent increase in the transport of both cytochrome C and hemoglobin. This effect was shown to be both specific and reversible.

Apolipoprotein E controls the risk and age at onset of Parkinson disease.

BACKGROUND: Similarities between Alzheimer disease (AD) and Parkinson disease (PD) suggest a possible role for apolipoprotein E (APOE) in PD. Most previous studies seeking to establish such a link used case-control datasets and results have been inconsistent. OBJECTIVE: To investigate APOE's role in PD using family-based association analyses. METHODS: APOE functional polymorphisms were genotyped for 658 PD affected families, including 282 multiplex and 376 singleton families. The pedigree disequilibrium test (PDT) and the genotype-PDT were used to test the risk effect of APOE. The Monks-Kaplan test was used to evaluate the effect of APOE on age at onset of PD. RESULTS: APOE was significantly associated with risk of developing PD. Stratified analysis revealed that APOE was most strongly associated with families with a positive PD family history (global p = 0.003). Like AD, the APOE-4 allele increases disease risk while the APOE-3 allele decreases risk. We detected a positive association of APOE-3 (p = 0.019) and a negative association of APOE-4 (p = 0.015) with age at onset in PD. CONCLUSIONS: The APOE-4 allele increases risk and decreases age at onset of PD, an association that may not be dependent upon cognitive impairment.

Scale and corrosion control with combined dolomite/calcite filter.

Water quality is a major operational issue for boiler operation and control. If the water is hard scale control is required and if it is soft then corrosion control is an issue. Here a two stream boiler test rig has been used to test the effect a fixed bed filter has on the scaling and corrosion properties of both hard and soft waters. The filter effectively controlled the pH, hardness and alkalinity of both waters leading to significant decreases in scale formation and effective control of corrosion.

Vagus nerve stimulation for essential tremor: a pilot efficacy and safety trial.

OBJECTIVE: To assess the safety and efficacy of vagus nerve stimulation (VNS) for essential tremor (ET). METHODS: This was a pilot open-treatment trial at three centers, with masked videotape tremor assessments. Inclusion required a severity score of 3 or 4 on the Tremor Rating Scale (TRS) in one or both hands. At baseline, tremor was assessed with TRS and Unified Tremor Rating Assessment (UTRA), accelerometry, and a videotape protocol. The VNS device was implanted with leads placed around the left cervical vagus nerve. Stimulation was adjusted over 4 weeks before the repeat tremor assessments. Two raters masked to the study visit scored the videotapes. RESULTS: Nine subjects participated, with a mean age of 65 years and a mean age at onset of tremor of 24. Investigators rated hand tremor as mildly improved (TRS 2.3 +/- 0.7 during VNS vs 3.0 +/- 0.4 during baseline, p = 0.06). Accelerometry-measured total power improved 50.2 +/- 31.8% (p < 0.01). Videotape tremor scores were highly correlated between the masked raters and revealed no changes in tremor scores with treatment. VNS was well tolerated, with the most common adverse events being stimulation related. CONCLUSIONS: VNS was judged by investigators to mildly improve upper extremity tremor. This finding was not confirmed in videotape scoring by masked raters. VNS is not likely to have a clinically meaningful effect on ET.

Isocratic separation of monosaccharides using immobilized Concanavalin A.

The successful fractionation of a mixture of monosaccharides using an immobilized lectin column operating under isocratic conditions is described. The key factors for effective separation were found to be sample size, feed velocity and column length. Under optimal conditions it was possible to obtain complete resolution of a mixture of L-arabinose, D-fructose and D-mannose in less than 40 min.

Genetic polymorphisms of the N-acetyltransferase genes and risk of Parkinson's disease.

Recently, the authors demonstrated linkage in idiopathic PD to a region on chromosome 8p that contains the N-acetyltransferase genes, NAT1 and NAT2. The authors examined NAT1 and NAT2 for association with PD using family-based association methods and single nucleotide polymorphisms (SNPs). The authors did not find evidence for association with increased risk for PD between any individual NAT1 or NAT2 SNP or acetylation haplotype (N = 397 families, 1,580 individuals).

A reversible hydrogel membrane for controlling the delivery of macromolecules.

Glucose-sensitive hydrogel membranes have been synthesized and characterized for their rate-of-delivery of macromolecules. The mechanism for changing this rate is based on variable displacement of the affinity interaction between dextran and concanavalin A (con A). Our main objective was to characterize the diffusion of model proteins (insulin, lysozyme, and BSA) through the membrane, in response to changes in environmental glucose concentrations. Membranes were constructed from crosslinked dextrans to which con A was coupled via a spacer arm. Changes in the porosity of the resulting hydrogel in the presence of glucose led to changes in the diffusion rate observed for a range of proteins. Gels of specified thickness were cast around to nylon gauze support (pore size, 0.1 mm) to improve mechanical strength. Diffusion of proteins through the gel membrane was determined using a twin-chamber diffusion cell with the concentrations being continuously monitored using a UV-spectrophotometer. Changes in the transport properties of the membranes in response to glucose were explored and it was found that, while 0.1M D-glucose caused a substantial, but saturateable, increase in the rates of diffusion of both insulin and lysozyme, controls using glycerol or L-glucose (0.1M) had no significant effect. Sequential addition and removal of external glucose in a stepwise manner showed that permeability changes were reversible. As expected, diffusion rates were inversely proportional to membrane thickness. A maximum increase in permeability was observed at pH 7.4 and at 37 degrees C. The results demonstrate that this hydrogel membrane functions as a smart material allowing control of solute delivery in response to specific changes in its external environment.

Epidemiologic study of 203 sibling pairs with Parkinson's disease: the GenePD study.

OBJECTIVE: To examine patterns of familial aggregation and factors influencing onset age in a sample of siblings with PD. METHODS: Sibling pairs (n = 203) with PD were collected as part of the GenePD study. Standardized family history, medical history, and risk factor data were collected and analyzed. RESULTS: The mean age at onset was 61.4 years and did not differ according to sex, exposure to coffee, alcohol, or pesticides. Head trauma was associated with younger onset (p = 0.03) and multivitamin use with later onset (p = 0.007). Age at onset correlation between sibling pairs was significant (r = 0.56, p = 0.001) and was larger than the correlation in year of onset (r = 0.29). The mean difference in onset age between siblings was 8.7 years (range, 0 to 30 years). Female sex was associated with increased frequency of relatives with PD. The frequency of affected parents (7.0%) and siblings (5.1%) was increased when compared with frequency in spouses (2.0%). CONCLUSIONS: The greater similarity for age at onset than for year of onset in sibling pairs with PD, together with increased risk for biological relatives over spouses of cases, supports a genetic component for PD. Risk to siblings in this series is increased over that seen in random series of PD cases; however, patients in this sample have similar ages at onset and sex distribution as seen for PD generally. These analyses suggest that factors influencing penetrance are critical to the understanding of this disease.

Complete genomic screen in Parkinson disease: evidence for multiple genes.

CONTEXT: The relative contribution of genes vs environment in idiopathic Parkinson disease (PD) is controversial. Although genetic studies have identified 2 genes in which mutations cause rare single-gene variants of PD and observational studies have suggested a genetic component, twin studies have suggested that little genetic contribution exists in the common forms of PD. OBJECTIVE: To identify genetic risk factors for idiopathic PD. DESIGN, SETTING, AND PARTICIPANTS: Genetic linkage study conducted 1995-2000 in which a complete genomic screen (n = 344 markers) was performed in 174 families with multiple individuals diagnosed as having idiopathic PD, identified through probands in 13 clinic populations in the continental United States and Australia. A total of 870 family members were studied: 378 diagnosed as having PD, 379 unaffected by PD, and 113 with unclear status. MAIN OUTCOME MEASURES: Logarithm of odds (lod) scores generated from parametric and nonparametric genetic linkage analysis. RESULTS: Two-point parametric maximum parametric lod score (MLOD) and multipoint nonparametric lod score (LOD) linkage analysis detected significant evidence for linkage to 5 distinct chromosomal regions: chromosome 6 in the parkin gene (MLOD = 5.07; LOD = 5.47) in families with at least 1 individual with PD onset at younger than 40 years, chromosomes 17q (MLOD = 2.28; LOD = 2.62), 8p (MLOD = 2.01; LOD = 2.22), and 5q (MLOD = 2.39; LOD = 1.50) overall and in families with late-onset PD, and chromosome 9q (MLOD = 1.52; LOD = 2.59) in families with both levodopa-responsive and levodopa-nonresponsive patients. CONCLUSIONS: Our data suggest that the parkin gene is important in early-onset PD and that multiple genetic factors may be important in the development of idiopathic late-onset PD.

Association of single-nucleotide polymorphisms of the tau gene with late-onset Parkinson disease.

CONTEXT: The human tau gene, which promotes assembly of neuronal microtubules, has been associated with several rare neurologic diseases that clinically include parkinsonian features. We recently observed linkage in idiopathic Parkinson disease (PD) to a region on chromosome 17q21 that contains the tau gene. These factors make tau a good candidate for investigation as a susceptibility gene for idiopathic PD, the most common form of the disease. OBJECTIVE: To investigate whether the tau gene is involved in idiopathic PD. DESIGN, SETTING, AND PARTICIPANTS: Among a sample of 1056 individuals from 235 families selected from 13 clinical centers in the United States and Australia and from a family ascertainment core center, we tested 5 single-nucleotide polymorphisms (SNPs) within the tau gene for association with PD, using family-based tests of association. Both affected (n = 426) and unaffected (n = 579) family members were included; 51 individuals had unclear PD status. Analyses were conducted to test individual SNPs and SNP haplotypes within the tau gene. MAIN OUTCOME MEASURE: Family-based tests of association, calculated using asymptotic distributions. RESULTS: Analysis of association between the SNPs and PD yielded significant evidence of association for 3 of the 5 SNPs tested: SNP 3, P =.03; SNP 9i, P =.04; and SNP 11, P =.04. The 2 other SNPs did not show evidence of significant association (SNP 9ii, P =.11, and SNP 9iii, P =.87). Strong evidence of association was found with haplotype analysis, with a positive association with one haplotype (P =.009) and a negative association with another haplotype (P =.007). Substantial linkage disequilibrium (P<.001) was detected between 4 of the 5 SNPs (SNPs 3, 9i, 9ii, and 11). CONCLUSIONS: This integrated approach of genetic linkage and positional association analyses implicates tau as a susceptibility gene for idiopathic PD.

Genome-wide scan for Parkinson's disease: the GenePD Study.

A genome-wide scan for idiopathic PD in a sample of 113 PD-affected sibling pairs is reported. Suggestive evidence for linkage was found for chromosomes 1 (214 cM, lod = 1.20), 9 (136 cM, lod = 1.30), 10 (88 cM, lod = 1.07), and 16 (114 cM, lod = 0.93). The chromosome 9 region overlaps the genes for dopamine beta-hydroxylase and torsion dystonia. Although no strong evidence for linkage was found for any locus, these results may be of value in comparison with similar studies by others.

Effect of contact time and inhibitor concentration on the affinity mediated adsorption of cells to surfaces.

Cell detachment by shear stress under conditions of laminar flow was used to investigate the effect of incubation time and soluble binding competitors on affinity mediated cell/surface interactions. Fractional attachment between yeast and a Concanavalin A (Con A) coated surface was studied as a function of adhesion time prior to exposure to shear in a parallel plate flow chamber. Two, four and sixteen hours adhesion times gave rise to significantly different fractional attachment profiles, with four hours giving greater cell retention.The effect of dextran as a competitive displacer of pre-attached cells was also examined using a number of exposure regimes. While the presence of dextran in the displacement buffer led to higher fractional displacement of pre-attached cells, this effect was magnified if an equilibration period between dextran solution and pre-attached cells was allowed before detachment was attempted. The decline in fractional attachment increased with incubation time up to 30 min, with longer periods resulting in a smaller effect. Pre-incubation of the Con A surface with dextran prior to the introduction of cells led to a 60% reduction in attachment.Attempts to determine critical shear values were complicated by the presence of a tightly bound cell fraction of approximately 15% that was not removed at the highest shear values used.

Stochastic modeling of affinity adsorption.

A stochastic model is described that allows surface proximity and packing effects to be incorporated into predictions of adsorption kinetics and equilibrium of affinity adsorption. Equilibrium predictions show that, depending on conditions chosen, the results obtained for equilibrium conditions can exhibit either a Freundlich- or a Langmuir-type relationship. Under conditions of surface density imposed adsorption constraints, the time taken for equilibrium to be reached increases as the "off" constant is decreased. This suggests that for resins having a high immobilized ligand density binding kinetics may be more highly limited by the "off" constant than by mass transfer limitations.

Pramipexole: a nonergot dopamine agonist as drug therapy in Parkinson's disease.

Pramipexole is a dopamine agonist that was recently introduced for the treatment of both early and advanced Parkinson's disease. Pramipexole is a synthetic aminobenzothiazole compound with a high affinity to D(3) receptors. It directly stimulates dopamine receptors without requiring metabolic conversion. Pramipexole is rapidly absorbed with bioavailability greater than 90% and is actively secreted by the renal tubules. The drug's plasma half-life is 8-12 h. Shown to be safe and effective as add-on therapy, pramipexole can also be used as initial dopaminergic therapy in Parkinson's disease, delaying the introduction of levodopa thereby postponing levodopa's side-effects.