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Biomedical subjects

Ronald F Pfeiffer

Publications and source records attributed to Ronald F Pfeiffer.

8 recordsLinked to original sources
PubMed2006

Continued efficacy and safety of subcutaneous apomorphine in patients with advanced Parkinson's disease.

The study purpose was to assess the efficacy of intermittent subcutaneous apomorphine (APO) as acute therapy for off episodes in advanced Parkinson's disease (PD) patients who had previously received APO for 3 months. Patients (n=62) were randomized to receive double-blind treatment with APO at their typically effective dose (TED; APO), APO at their TED+0.2mL (2.0mg; APO+2), placebo at volume equal to their TED (PL), or placebo at volume equal to their TED+0.2mL (PL+2), for a single off episode. Significantly greater improvement in mean Unified PD rating scale motor scores was seen with pooled APO versus pooled placebo 20min after administration (-24.2 vs. -7.4; p<0.0001); the difference was also significant at 10min (p<0.0001). Overall adverse event incidence did not significantly differ between pooled APO and pooled PL. This study supports the long-term use of intermittent APO as effective acute therapy for off episodes in advanced PD patients.

Aged↗
PubMed2005

A multicenter, open-label, sequential study comparing preferences for carbidopa-levodopa orally disintegrating tablets and conventional tablets in subjects with Parkinson's disease.

BACKGROUND: Patients with Parkinson's disease (PD) may have difficulty taking their medications for various reasons. In these patients, orally disintegrating tablets (ODTs) can be given without water and may provide greater convenience and ease of use than conventional tablets. OBJECTIVE: This study compared preferences for ODTs with those of the conventional tablet formulation of the antiparkinsonism combination drug carbidopa-levodopa (C.-L.) in subjects with PD. METHODS: Subjects aged > or =18 years with PD controlled using a stable dosage of C-L were enrolled in this multicenter, open-label, sequential study. Subjects received their stable dose of conventional C-L for 7 +/- 3 days. They were then switched to the same dose of C-L in the ODT formulation for 14.+/- 3 days. During the last 3 days of each treatment period, subjects were to record in a diary their "on" and "off" times (asymptomatic and symptomatic parkinsonism, respectively) and medication use. On the final day of each treatment period, the Unified Parkinson's Disease Rating Scale (UPDRS) was administered to subjects before the first morning dose and then after dosing when they mentioned they were experiencing the "on" state. A Global Preference Questionnaire (GPQ) was completed by subjects at the end of the study. The primary variable was response to all GPQ items. Secondary variables were changes in UPDRS score and mean amount of "off" time per 24 hours. Adverse effects (AEs) also were monitored. RESULTS: Sixty-one subjects (31 men, 30 women; mean[SD] age, 71.8 [8.3] years; mean body weight, 76.2 kg) participated in the study and were included in the AE assessment; 60 completed the study and were included in the efficacy assessment. Twenty-seven subjects (45%) preferred ODTs compared with 12 (20%) who preferred the conventional tablets (P < 0.017). The remaining 21 subjects (35%) had no preference. The attributes of the ODTs that influenced subjects' preference for that formulation included accessibility to medication to treat "off" times (30 [50%]); ease of activities of daily living (28 [47%]); reduced concern about swallowing the medication (27 [45%]); and use for nighttime dosing, ease of compliance with dosing schedule, and feeling less self-conscious about others noticing medication use (each, 25 [42%]) (all, P < 0.001). No statistically significant differences in UPDRS scores in the "on" and "off" states were found between the 2 formulations. The incidence of AEs was statistically similar between the 2 formulations. CONCLUSIONS: In this small study of ODT C-L versus conventional C-L tablets in these adult subjects with PD, the results suggest that the ODTs may be of value in certain patients with PD, depending on their personal preferences, disease status, and willingness to alter an aspect of their medication use. For selected patients with PD, the ODT C-L formulation may provide increased convenience, ease of use, and rapid access to medication.

Aged↗
PubMed2004

Mutations in LRRK2 cause autosomal-dominant parkinsonism with pleomorphic pathology.

We have previously linked families with autosomal-dominant, late-onset parkinsonism to chromosome 12p11.2-q13.1 (PARK8). By high-resolution recombination mapping and candidate gene sequencing in 46 families, we have found six disease-segregating mutations (five missense and one putative splice site mutation) in a gene encoding a large, multifunctional protein, LRRK2 (leucine-rich repeat kinase 2). It belongs to the ROCO protein family and includes a protein kinase domain of the MAPKKK class and several other major functional domains. Within affected carriers of families A and D, six post mortem diagnoses reveal brainstem dopaminergic degeneration accompanied by strikingly diverse pathologies. These include abnormalities consistent with Lewy body Parkinson's disease, diffuse Lewy body disease, nigral degeneration without distinctive histopathology, and progressive supranuclear palsy-like pathology. Clinical diagnoses of Parkinsonism with dementia or amyotrophy or both, with their associated pathologies, are also noted. Hence, LRRK2 may be central to the pathogenesis of several major neurodegenerative disorders associated with parkinsonism.

Adult↗
PubMed2003

The PARK8 locus in autosomal dominant parkinsonism: confirmation of linkage and further delineation of the disease-containing interval.

Recently, a new locus (PARK8) for autosomal dominant parkinsonism has been identified in one large Japanese family. Linkage has been shown to a 16-cM centromeric region of chromosome 12, between markers D12S1631 and D12S339. We tested 21 white families with Parkinson disease and an inheritance pattern compatible with autosomal dominant transmission for linkage in this region. Criteria for inclusion were at least three affected individuals in more than one generation. A total of 29 markers were used to saturate the candidate region. One hundred sixty-seven family members were tested (84 affected and 83 unaffected). Under the assumption of heterogeneity and through use of an affecteds-only model, a maximum multipoint LOD score of 2.01 was achieved in the total sample, with an estimated proportion of families with linkage of 0.32. This LOD score is significant for linkage in a replication study and corresponds to a P value of.0047. Two families (family A [German Canadian] and family D [from western Nebraska]) reached significant linkage on their own, with a combined maximum multipoint LOD score of 3.33, calculated with an affecteds-only model (family A: LOD score 1.67, P=.0028; family D: LOD score 1.67, P=.0028). When a penetrance-dependent model was calculated, the combined multipoint LOD score achieved was 3.92 (family A: LOD score 1.68, P=.0027; family D: LOD score 2.24, P=.0007). On the basis of the multipoint analysis for the combined families A and D, the 1-LOD support interval suggests that the most likely disease location is between a CA repeat polymorphism on genomic clone AC025253 (44.5 Mb) and marker D12S1701 (47.7 Mb). Our data provide evidence that the PARK8 locus is responsible for the disease in a subset of families of white ancestry with autosomal dominant parkinsonism, suggesting that it could be a more common locus.

Chromosome Mapping↗
PubMed2003

Gastrointestinal dysfunction in Parkinson's disease.

There is growing recognition that gastrointestinal dysfunction is common in Parkinson's disease (PD). Virtually all parts of the gastrointestinal tract can be affected, in some cases early in the disease course. Weight loss is common but poorly understood in people with PD. Dysphagia can result from dysfunction at the mouth, pharynx, and oesophagus and may predispose individuals to aspiration (accidental inhalation of food or liquid). Gastroparesis can produce various symptoms in patients with PD and may cause erratic absorption of drugs given to treat the disorder. Bowel dysfunction can consist of both slowed colonic transit with consequent reduced bowel-movement frequency, and difficulty with the act of defecation itself with excessive straining and incomplete emptying. Recognition of these gastrointestinal complications can lead to earlier and potentially more effective therapeutic intervention.

Gastrointestinal Diseases↗
PubMed2002

Anticardiolipin antibody in vascular parkinsonism.

Vascular parkinsonism (VP) is characterized by predominantly lower body involvement with gait impairment and postural instability, often without tremor, and by relative levodopa unresponsiveness. Neuroimaging studies demonstrate multiple infarcts or ischemic changes in periventricular white matter. Anticardiolipin antibodies (ACLA) are associated with hypercoagulable states and increased stroke risk. Review of our Movement Disorders Clinic records identified 44 individuals with a diagnosis of VP. ACLA have been obtained in 22 of these patients (mean age, 78.3 years; mean Mini-Mental Status Exam score, 25.8). Gait disturbance was the initial clinical feature in 82% of the patients, and levodopa responsiveness was present in 18% of those treated. In 9 of the 22 (40.9%), ACLA immunoglobulin G was positive. No significant differences in clinical features or risk factors (hypertension, diabetes, coronary artery disease, and clinical stroke) were evident between ACLA+ and ACLA- groups. Since the presence of ACLA in individuals with stroke is usually treated by full-scale anticoagulation with warfarin, our findings raise the question whether such treatment should also be used in persons with VP who are ACLA positive.

Aged↗
PubMed2002

Potential of transdermal drug delivery in Parkinson's disease.

There has been a growing recognition that pulsatile stimulation of dopamine receptors may be an important mechanism in the generation of the motor fluctuations that often develop and compromise the effectiveness of long-term levodopa administration in persons with Parkinson's disease (PD). This has prompted investigation of treatment approaches that might provide more constant, and therefore physiological, dopamine receptor stimulation. Frequent levodopa administration, controlled-release levodopa preparations, inhibitors of levodopa metabolism, and duodenal, subcutaneous and even intravenous infusions of levodopa or dopamine agonists have all been employed with this goal in mind, but all have limitations. Transdermal drug delivery is a treatment approach that is not only capable of providing a constant rate of drug delivery, but is also non-invasive and relatively simple to use. However, developing a drug to be delivered transdermally for the treatment of PD has been anything but easy. Levodopa and many dopamine agonists are not sufficiently soluble to be administered via the transdermal route, and blind alleys have been encountered thus far in the investigation of suitably soluble drugs. Nevertheless, investigation continues and yet another candidate drug, rotigotine (N-0923), is currently under active investigation. Techniques designed to enhance skin permeation and thus improve the effectiveness of transdermal drug delivery are also potential sources for future treatment advances.

Administration, Cutaneous↗