Treatment of mildly to moderately active ulcerative colitis with a tryptase inhibitor (APC 2059): an open-label pilot study.

BACKGROUND: Mast cells isolated from the colonic mucosa in active ulcerative colitis appear to be partially degranulated, suggesting the release of tryptase. AIM: To investigate the safety and activity of APC 2059, a highly specific tryptase inhibitor, in the treatment of ulcerative colitis. METHODS: This was an open-label, Phase 2, multicentre pilot study in patients with mildly to moderately active ulcerative colitis, with a disease activity index of 6-9 on a 12-point scale. Fifty-six adults received 20 mg APC 2059 subcutaneously twice daily and 53 completed 28 days of treatment. The primary end-point was response, defined as a final disease activity index of < or = 3. Supplementary analyses were also performed. RESULTS: Sixteen (29%) of 56 patients responded. Five (9%) showed complete remission (disease activity index=0). Twenty-seven (49%) improved, with a final disease activity index of < or = 3 or a four-point reduction. Improvement or normalization in each category of the disease activity index was as follows: stool frequency, 64%; bleeding, 64%; endoscopy, 50%; physicians' rating, 63%. There were no significant relationships between outcome and pharmacokinetics. The most common adverse events were related to the injection site (32.1%). CONCLUSIONS: In this pilot study, the tryptase inhibitor APC 2059 was safe and there was evidence of activity in the treatment of ulcerative colitis.

Clinical trials in Alzheimer's disease. Calculating Alzheimer's Disease Assessment Scale-cognitive subsection with the data from the consortium to establish a registry for Alzheimer's disease.

The database of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) is a seminal work in the field of cognitive dysfunction and Alzheimer's disease. This 24-center study of 1,094 patients with Alzheimer's disease who received no treatment for their cognitive dysfunction and 463 normal control subjects is rich in neurobehavioral data and contains extensive imaging and neuropathologic findings. However, the Alzheimer's Disease Assessment Scale (ADAS) was not administered as part of the CERAD study, which limits the study's applicability to modern drug trials, in which the ADAS-cognitive subsection (ADAS-cog) is a popular end point. The purpose of this investigation was to develop a derived ADAS-cog score from the neurobehavioral data obtained from subjects during their evaluation in the CERAD study. Two calculated ADAS-cog scores were developed. The first was based on clinically mapping the items on the ADAS-cog to assessments that were performed in the CERAD study. The second was based on rescaling the Mini-Mental Status Exam (MMSE), using published results correlating the ADAS-cog to the MMSE. Standard characteristics of both calculated ADAS-cog scores were calculated and compared with each other and with the literature. Both calculated ADAS-cog scores performed comparably to published characteristics of the ADAS-cog. The clinically based calculated ADAS-cog outperformed the rescaled MMSE. Using the CERAD database, it is now possible to model the progression of an untreated (placebo) population of patients with Alzheimer's disease and correlate it to a study using ADAS-cog.

Clinical, pharmacokinetic, and pharmacodynamic effects of tolcapone withdrawal in levodopa-treated patients with parkinsonism.

The effect and clinical significance of tolcapone withdrawal on erythrocyte catechol-O-methyltransferase (COMT) activity, levodopa pharmacokinetics, and levodopa requirements were investigated in 59 patients with fluctuating parkinsonism who were randomized to receive placebo or tolcapone 100 or 200 mg three times daily for 6 weeks. Tolcapone withdrawal caused a transient elevation in COMT activity by 64% in patients receiving 100 mg three times daily and by 128% in those receiving 200 mg three times daily at approximately 1-2 weeks after discontinuation of drug. Thereafter, COMT activity was declining but did not reach baseline values by the 12-week study endpoint. However, this had no effect on plasma levodopa and 3-O-methyldopa (3-OMD) concentrations or on levodopa requirements. During treatment, tolcapone increased "on" time and decreased "off" time; after discontinuation of study medication and levodopa dose adjustment, on and off times were similar to baseline. Withdrawal was generally well tolerated; no patients withdrew from the trial during the posttreatment period, and no serious adverse events were observed. In conclusion, the transient increase in erythrocyte COMT activity observed after discontinuation oftolcapone is not associated with changes in peripheral levodopa metabolism and therefore has no significant clinical consequences in terms of levodopa requirements, clinical symptoms, or adverse events.

Genetic predisposition plays a role in nigral cell death in Parkinson's disease.

Both genetic and environmental factors are involved in the etiology of Parkinson's disease (PD). The recent identification of specific autosomal genes that lead to variants of PD confirms that genetic factors are important. Identifying and confirming other genetic factors responsible for PD is a difficult task because PD is a complex disease, the results of multiple genetic and environmental factors leading to a final common pathology. This review will discuss how advances in human genetics will allow future unraveling of the complex interactions between genetics and environment in the etiology of PD.

Gene-toxin interaction as a putative risk factor for Parkinson's disease with dementia.

We had previously examined environmental, sociodemographic and clinical variables as predictors for Parkinson's disease with dementia (PD + D) and found that lower educational attainment, greater motor impairment and advanced age at disease onset were more common in PD + D than in subjects with Parkinson's disease without dementia (PD-D). We now explore the hypothesis that genetic traits coupled with nongenetic factors may raise the risk of development of PD + D. The study cohort of 43 PD + D and 51 PD-D subjects was analyzed examining environmental, sociodemographic and clinical variables along with 3 candidate gene markers: poor debrisoquine metabolizer allele (CYP 2D6 29B+), monoamine oxidase B allele 1, and apolipoprotein E epsilon 4 allele. Variables were initially entered into a multivariate model singly. Again lower education, age at onset and motor impairment appeared as predictors of PD + D while other variables (including allele status) failed to emerge as significant individual risk factors for dementia. We then examined environmental and genetic variables analyzed in tandem to look for potential variable interactions. Subjects who had pesticide exposure and at least 1 copy of the CYP 2D6 29B+ allele had 83% predicted probability of PD + D (stepwise logistic regression model: p = 0.0491). This case-control study provides preliminary evidence that a gene-toxin interaction may play an etiological role in PD + D. Further assessment of the role of these putative risk factors in incident dementia in PD is indicated.

COMT inhibition: a new treatment strategy for Parkinson's disease.

During the initial stages of Parkinson's disease, treatment with levodopa plus a decarboxylase inhibitor (carbidopa or benserazide) provides adequate control of symptoms. However, as the disease progresses, the clinical response to treatment often begins to fluctuate, becoming increasingly correlated with fluctuations in plasma concentrations of levodopa-the "wearing-off" phenomenon. Many strategies have attempted, with various degrees of success, to increase the availability of levodopa and its active metabolites, thus reducing these fluctuations in response. This review focuses on the role of the new catechol O-methyltransferase (COMT) inhibitors tolcapone and entacapone as adjuncts to levodopa therapy. These agents act effectively and safely to increase the amount of levodopa that is available to enter the brain by extending the half-life of levodopa, resulting in more stable levels in the plasma and prolonging "on" time.

Using liquid levodopa in the treatment of Parkinson's disease. A practical guide.

Many patients with Parkinson's disease develop both involuntary movements from and a critical dependency on, levodopa therapy as their disease progresses. This results in a narrow therapeutic window in which blood concentrations of levodopa can achieve optimal control of parkinsonian symptoms. The short half-life of levodopa, combined with loss of intraneuronal storage capacity for levodopa as the disease progresses, results in patients experiencing marked motor fluctuations complicated by medication-induced dyskinesias. When given in tablet form, the dosage of levodopa (which is usually combined with a decarboxylase inhibitor such as carbidopa or benserazide) often cannot be titrated adequately, and the drug may become unpredictable in its ability to relieve parkinsonian symptoms. A solution of levodopa and carbidopa, stabilised using ascorbic acid, offers a means of delivering a titrated amount of levodopa at regular intervals. Solutions pass through the stomach faster than solids, affording more rapid symptomatic relief in some patients with Parkinson's disease.

Tolcapone improves motor function and reduces levodopa requirement in patients with Parkinson's disease experiencing motor fluctuations: a multicenter, double-blind, randomized, placebo-controlled trial. Tolcapone Fluctuator Study Group I.

Tolcapone is a potent catechol-O-methyltransferase inhibitor that prolongs the plasma half-life of levodopa. This multicenter, double-blind, placebo-controlled study used two 10-hour clinical evaluations to compare the efficacy and safety of three doses of tolcapone (50, 200, and 400 mg tid) with placebo in patients with Parkinson's disease (PD) experiencing motor fluctuations from levodopa/carbidopa. One hundred fifty-one patients completed the study. Clinical evaluations lasting 10 hours were performed on day -1 and day 42 using United Parkinson's Disease Rating Scale motor subscale and "on/off" and dyskinesia assessments every 30 minutes. Tolcapone significantly reduced "off" time an average of 40% and increased total "on" time by about 25% at all dose levels, as compared to placebo treatment. Levodopa/carbidopa dosage and frequency were significantly reduced. Tolcapone was well tolerated, with patients experiencing typical dopaminergic side effects that could be reduced or eliminated by lowering levodopa/carbidopa dosages. Tolcapone was effective at prolonging the clinical benefit of levodopa and reducing total levodopa requirements in PD patients with motor fluctuations.

Prevalence of tremor and Parkinson's disease.

To determine the prevalence of essential tremor (ET) and Parkinson's disease (PD) in a retirement community, all residents of Carefree, Arizona, aged over 65 years were contacted. All participants completed validated questionnaires for PD and ET, and were examined using the Unified Parkinson's Disease Rating Scale. Of 356 individuals evaluated, 155 (43.5%) had tremor; 73 (20.5%) had ET; 26 (7.3%) had PD; and 56 (15.7%) had postural tremor (PT). Thus, a large percentage of individuals were found to have tremor, in the plurality of whom it could be classified as ET. The number of individuals with Parkinson's disease exceeded our expectations.

Variant cytochrome P450 CYP2D6 allelic frequencies in Parkinson's disease.

Aberrant detoxification of environmental agents may be the basis for an inherited predisposition to Parkinson's disease. A CYP2D6 genetic marker of the debrisoquine hydroxylase "poor metabolizer" phenotype was found to be significantly increased in Parkinson's disease patients compared to controls, as has been shown in previous studies. Presence of this marker gives an odds ratio of 1.86 for Parkinson's disease (95% confidence interval 1.33-2.39, P < 0.02). For comparison, a CYP1A1 polymorphism, which is not known to be associated with aberrant drug metabolism, showed no association with Parkinson's disease in our study.

Double-blind, placebo-controlled, crossover study of duodenal infusion of levodopa/carbidopa in Parkinson's disease patients with 'on-off' fluctuations.

Ten patients with Parkinson's disease suffering severe motor fluctuations completed a double-blind, placebo-controlled, crossover trial of duodenal infusion of levodopa/carbidopa to determine if this technique improved the duration of functional time by reducing plasma levodopa level variability. With infusion, seven patients experienced increased functional "on" hours and decreased number of "off" episodes; however, two patients were slightly worse and one patient experienced no benefit. All 10 patients had significantly decreased variability in levodopa levels permitting better titration of levodopa dosage to individual requirements. Five patients continued to use infusion 12 to 20 months after completion of this study. Selected patients with Parkinson's disease who experience severe motor fluctuations may benefit from duodenal infusion with an improved and prolonged response to medication.

Oral levodopa/carbidopa solution versus tablets in Parkinson's patients with severe fluctuations: a pilot study.

Four patients with Parkinson's disease, optimally treated with levodopa/carbidopa (LD/CD) tablets but experiencing severe motor fluctuations, underwent an open trial of a levodopa/carbidopa/ascorbic acid solution (LCAS) orally at timed intervals. LCAS reduced bradykinesia, decreased dysfunctional dyskinesia, and increased functional "on" time when compared with previous LD/CD tablet therapy. Oral LCAS allowed better titration of levodopa dosage and offered a more predictable response than LD/CD tablets. Preparation and oral consumption of LCAS was easy and inexpensive. LCAS may be a practical alternative for patients whose motor fluctuations fail to respond to optimal therapy with LD/CD tablets.

Glutamate receptor-induced 45Ca2+ accumulation in cortical cell culture correlates with subsequent neuronal degeneration.

Murine neuronal and glial cell cultures exposed briefly to glutamate accumulated large amounts of 45Ca2+ from the extracellular medium during the exposure. Most of the accumulation likely reflected influx into neurons, as little accumulation was observed in similarly treated glial cultures. When the concentration of glutamate was varied between 10 and 1000 microM, or exposure duration was varied between 0 and 10 min, the amount of 45Ca2+ accumulation correlated closely with the amount of neuronal death 24 hr later. Both 45Ca2+ accumulation and cell death could be attenuated in a dose-dependent manner by the competitive NMDA antagonist D-aminophosphonovalerate or the noncompetitive antagonist dextrorphan, with IC50 values of approximately 100 microM and 15 microM, respectively. In contrast, neither 45Ca2+ accumulation nor cell death was blocked by the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) in the presence of high glycine. With brief exposure, high concentrations of AMPA, kainate, or K+ produced much less death or 45Ca2+ accumulation than produced by glutamate, especially if 10 microM MK-801 was included in the exposure medium to block NMDA receptor activation. Kainate- or AMPA-induced 45Ca2+ accumulation or neuronal cell death was blocked with CNQX. However, high K(+)-triggered 45Ca2+ accumulation was only partially blocked with CNQX plus MK-801, consistent with mediation by voltage-gated Ca2+ channels. In addition to measuring the accumulation of 45Ca2+ occurring during agonist exposure, we also assessed accumulation during the 30 min immediately following completion of a 3-5 min exposure to 500 microM NMDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of a monoamine oxidase B allele with Parkinson's disease.

Monoamine oxidase B (MAO-B) is implicated in the cause of Parkinson's disease (PD) because of its role in metabolizing the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and forming H2O2 during dopamine metabolism. Altered MAO-B activity has been observed in PD platelets. Polymerase chain reaction was used to amplify a portion of the MAO-B gene. Polymerase chain reaction products were screened with restriction enzymes to identify fragments useful for single-stranded conformational polymorphism analysis. A single-stranded conformational polymorphism was identified in an MAO-B polymerase chain reaction product after Hae III digestion. One hundred twenty-one control individuals were allelotyped with frequencies of 0.45 and 0.55 for alleles 1 and 2, respectively. Frequencies of 0.62 and 0.38 (1 and 2, respectively) were observed in a population of 46 patients with PD. The presence of MAO-B allele 1 is associated with a relative risk for PD of 2.03-fold (confidence interval, 1.44-2.61; p < 0.02). For comparison, a monoamine oxidase A polymorphism was used to determine allelic frequencies in these same populations and no statistically significant differences were found. These results suggest that an inherited variant of MAO-B may be involved in a genetic predisposition for PD.

Linkage analysis of the monoamine A and B genes using newly-defined polymorphisms.

The monoamine oxidase A (MAOA) and B (MAOB) genes have been localized to chromosome Xp11.3. Recently-defined polymorphisms and linkage analysis have shown tight linkage between MAOA and MAOB, with a distance of approximately 2.7 cM between them.

Actin-gelsolin interactions. Evidence for two actin-binding sites.

We have used a fluorescence enhancement of actin labeled with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-actin) to study the interactions between rabbit skeletal muscle G-actin and either purified platelet gelsolin or a 130-kDa binary complex of platelet actin and gelsolin that is stable in EGTA and can be purified from human platelets. We have delineated four binding reactions. The exchange of Mg2+ for Ca2+ on the divalent cation-binding site of NBD-actin gives a small fluorescence increase. Binding of monomeric NBD-actin to the binary complex results in a 2.5-fold increase in the emission at 530 nm in the presence of Ca2+ and a 2-fold increase in the presence of EGTA. Titration experiments show that, under nonpolymerizing conditions, one additional actin is bound to the 130-kDa species to form a ternary complex. This binding is Ca2+-sensitive. Purified gelsolin does not appear to bind to NBD-actin in the presence of EGTA, as determined by fluorescence enhancement, gel filtration, or sedimentation measurements, but the addition of Ca2+ promotes rapid binding with a 1.6-1.7-fold enhancement of the emission intensity. A comparison of the relative fluorescence yields/NBD-actin molecule for a binary complex of gelsolin and one NBD-actin, a ternary complex of gelsolin and two NBD-actin molecules, and a ternary complex with an unlabeled actin in the EGTA-stable site and an NBD-actin in the second site indicates that the first NBD-actin, in the EGTA-stable site, does not give a fluorescence increase on binding but the second one does. Finally, we have demonstrated that one molecule of 45Ca2+ is "trapped" when the binary complex is formed and cannot be removed by EGTA. A summary model for these reactions is presented that indicates the interaction between actin and gelsolin is not a freely reversible Ca2+-controlled reaction.

Platelet activation induces the formation of a stable gelsolin-actin complex from monomeric gelsolin.

We have studied the interactions between gelsolin and actin in crude extracts from activated and unactivated platelets and in mixtures of purified platelet gelsolin and muscle actin. Extracts were prepared using 10 mM EGTA from human platelets treated either with 100 microM aspirin and 2.5 mM tetracaine to retard activation or with the calcium ionophore A23187 to effect activation. The extracts were fractionated by gel filtration on Sephadex G-150 or by sedimentation on sucrose gradients and then analyzed using anti-gelsolin immunoblots and actin filament nucleation assays. The nucleation activity in both extracts was associated with gelsolin. The activity in the extracts from unactivated platelets sedimented with an S value of 5.2 and had an Mr = 90,000. The activity in the extracts prepared with EGTA from activated platelets sedimented at 6.8 S and had an Mr = 130,000. We have shown previously that the Mr = 130,000 species is an EGTA-stable binary complex of one actin and one gelsolin. Transient exposure of the extracts from unactivated platelets to 100 microM Ca2+ and subsequent fractionation in EGTA-containing buffers demonstrated that the formation of the binary complex occurs in the presence of Ca2+. Fractionation in the presence of 100 microM Ca2+ demonstrated higher order complexes including a ternary complex with a sedimentation constant of 8.2 S and an Mr = 165,000. Sedimentation and gel filtration experiments using purified platelet gelsolin and rabbit skeletal muscle actin demonstrated that formation of the EGTA-stable binary complex required Ca2+. At least one additional actin is bound to the binary complex in the presence of Ca2+, but is not sufficiently stable to be purified when EGTA is added. The results suggest that gelsolin exists either as a monomer or perhaps as a weak complex with actin in unactivated platelets but complexes tightly with actin during the transient Ca2+ rise that occurs during activation.

Purification and characterization of a gelsolin-actin complex from human platelets. Evidence for Ca2+-insensitive functions.

Extracts of human platelets contain a 90,000-Da protein that is retained by DNase I-agarose in the presence of Ca2+. The 90-kDa protein, tightly complexed with platelet actin, can be eluted from DNase I-agarose by ethylene glycol bis(beta-aminoethyl ether)-N, N,N',N'-tetraacetic acid (EGTA). The platelet 90-kDa protein is immunologically related to rabbit macrophage gelsolin. The 90-kDa protein-actin complex was purified from platelet extracts using DEAE-Sephacel, Sephadex G-200, and hydroxyapatite and is stable in EGTA and 0.8 M KCl. The purified complex will modulate the assembly of fluorescently labeled 7-chloro-4-nitrobenzo-2-oxa-1, 3-diazole-actin in the presence of both Ca2+ and EGTA. In addition, the complex affects the low shear viscosity of F-actin solutions in the presence of both Ca2+ and EGTA. Finally, the complex increases the critical concentration for actin assembly about 4-fold. The results are consistent with a strong preferential binding to or capping of the barbed end of actin filaments by the complex in either Ca2+ or EGTA.