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Biomedical subjects

P A LeWitt

Publications and source records attributed to P A LeWitt.

At least 19 recordsLinked to original sources
PubMed2003

Tissue inhibitors of matrix metalloproteinases are elevated in cerebrospinal fluid of neurodegenerative diseases.

Matrix metalloproteinases (MMPs) are implicated in the pathogenesis of diseases such as Alzheimer's Disease (AD) and amyotrophic lateral sclerosis (ALS). Increased expression of MMP-9 and TIMPs has been reported in postmortem AD and ALS brain tissue, as well as in ALS cerebrospinal fluid (CSF) and plasma. Although individual studies of MMP and TIMP expression in CSF have included AD and ALS samples, there are no studies comparing the expression of these proteins between neurodegenerative diseases. We measured the levels of matrix metalloproteinases (MMPs)-2 and -9 and the tissue inhibitor of MMPs (e.g. TIMP-1 and TIMP-2) in CSF samples from patients with Parkinson's Disease (PD), Huntington's Disease (HD), AD and ALS as compared to age-matched control patients. There was constitutive expression of the proform of gelatinase A (proMMP-2) on zymography gels in all CSF samples. Unexpectedly, there was an additional gelatinolytic band at 130 kDa of unknown etiology in the CSF samples of patients with PD (61% of patients studied), AD (61%), HD (25%) and ALS (39%). Levels of TIMP-1 were significantly elevated in CSF samples from all disease groups. TIMP-2 was significantly increased in CSF of AD and HD patients. MMP-2 levels did not differ significantly between groups. These findings show that TIMPs are elevated in the CSF of patients with neurodegenerative diseases suggesting a potential role of these endogenous inhibitors of matrix metalloproteinases in neurodegenerative diseases.

Adult↗
PubMed2001

A randomized, double-blind, placebo-controlled trial of subcutaneously injected apomorphine for parkinsonian off-state events.

OBJECTIVE: To assess the safety and efficacy of subcutaneous apomorphine hydrochloride administration for off-state (poor motor function) periods in patients with Parkinson disease with motor fluctuations under both inpatient titration and outpatient therapeutic conditions. PATIENTS AND METHODS: Twenty-nine patients had advanced Parkinson disease with 2 hours or more off time despite aggressive oral therapy. Patients randomly received titrated doses of subcutaneous apomorphine hydrochloride (2-10 mg, n = 20) or pH-matched vehicle placebo (n = 9) during an inpatient and 1-month outpatient phase. A change in the United Parkinson Disease Rating Scale motor score 20 minutes after inpatient dosing during a practically defined off-state event and the percentage of injections successfully aborting off-state events were the primary inpatient and outpatient efficacy factors. RESULTS: The average (SEM) levodopa equivalent dose of apomorphine hydrochloride was 5.4 +/- 0.5 mg and the mean placebo dose was 1.0 mL. Mean inpatient United Parkinson Disease Rating Scale motor scores were reduced by 23.9 and 0.1 points (62% and 1%) by apomorphine treatment and placebo, respectively (P<.001). The mean percentage of outpatient injections resulting in successful abortion of off-state events was 95% for apomorphine and 23% for placebo (P<.001). Inpatient response was significantly correlated with and predictive of outpatient efficacy (P<.001). The levodopa dose was not predictive of the apomorphine dose requirement. Frequent adverse events included dyskinesia, yawning, and injection site reactions. CONCLUSION: Apomorphine by intermittent subcutaneous injection is effective and safe for outpatient use to reverse off-state events that occur despite optimized oral therapy.

Aged↗
PubMed2001

Transdermal dopaminergic D(2) receptor agonist therapy in Parkinson's disease with N-0923 TDS: a double-blind, placebo-controlled study.

N-0923 is a non-ergot, dopaminergic D(2) agonist designed to be transdermally available. It has anti-parkinsonian effects when infused intravenously. An adhesive matrix patch was developed to deliver N-0923 transdermally (N-0923 TDS). In this phase II trial, we evaluated the effectiveness of various doses of N-0923 TDS at replacing levodopa. Eighty-five Parkinson's disease (PD) patients were randomized to placebo or one of four doses of N-0923 TDS for 21 days. Change in daily levodopa dose was the primary efficacy measure. Significantly greater reductions in levodopa dose were achieved as compared to placebo for the two highest doses of N-0923 TDS. Patients treated with 33.5 mg and 67 mg N-0923 TDS decreased levodopa use by 26% and 28%, vs. 7% for placebo. N-0923 TDS was safe and well tolerated.

Administration, Cutaneous↗
PubMed2001

Ceruloplasmin immunoreactivity in neurodegenerative disorders.

Ceruloplasmin (CP) is a 132 kd cuproprotein which, together with transferrin, provides the majority of anti-oxidant capacity in serum. Increased iron deposition and lipid peroxidation in the basal ganglia of subjects with hereditary CP deficiency suggest that CP may serve as an anti-oxidant in the brain as well. The present study compared CP immunoreactivity in brain specimens from normal controls and subjects with neurodegenerative disorders (Alzheimer's disease [AD], Parkinson's disease [PD], progressive supranuclear palsy [PSP], and Huntington's disease [HD]) (n = 5 per group). The relative intensity of neuronal CP staining and the numbers of CP-stained neurons per 25x microscope field were determined in hippocampus (CA1, subiculum, and parahippocampal gyrus), parietal cortex, frontal cortex, substantia nigra, and caudate. CP was detected in both neurons and astrocytes in all specimens, and in senile plaques and occasional neurofibrillary tangles in AD brain. Neuronal CP staining intensity tended to increase in most AD brain regions, but was statistically significant vs controls only in the CA1 region of hippocampus (p = .016). Neuronal CP staining in brain specimens from other neurodegenerative disorders showed a slight but nonsignificant increase vs controls. The numbers of CP-stained neurons per field did not differ between the various neurodegenerative disorders and controls. These results suggest that a modest increase in neuronal CP content is present in the AD brain, and lesser elevations in neuronal CP occur in the other neurodegenerative disorders in this study. Though CP functions as both an acute phase protein and an anti-oxidant in peripheral tissues, whether it does so in the brain remains to be determined.

Aged↗
PubMed2000

Purine-induced alterations of dopamine metabolism in rat pheochromocytoma PC12 cells.

Studies with cerebrospinal fluid from subjects with Parkinson's disease suggest that purine abnormalities may be present in this disorder. The effects of purines on dopamine metabolism have not been characterized, though adenosine is known to inhibit dopaminergic neurotransmission. In this study, dopamine, its precursor 3,4-dihydroxyphenylalanine (DOPA), and its degradation products 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) were measured in rat pheochromocytoma PC12 cells following 24-h incubation with 5, 50, and 500 microM adenosine, adenine, guanosine, guanine, hypoxanthine, xanthine, and uric acid. Incubation with adenosine increased DOPA, DOPAC, and HVA, while adenine treatment decreased DOPA. Guanosine (500 microM) decreased DOPA, dopamine, and DOPAC, while lower concentrations increased DOPAC and HVA. Incubation with guanine decreased dopamine, and xanthine decreased dopamine and DOPAC. Hypoxanthine and uric acid exerted minimal effects. These results indicate that purines exert a variety of effects on dopamine metabolism. The influence of purine metabolism on the dopaminergic deficit in the Parkinsonian brain merits further investigation.

Adenine↗
PubMed2000

Monoamine changes in the brain of BALB/c mice following sub-lethal infection with Nocardia asteroides (GUH-2).

BALB/c mice injected intravenously with a single, sub-lethal dose of Nocardia asteroides GUH-2 develop several levodopa responsive movement disorders. These included headshake, stooped posture, bradykinesia, and hesitation to forward movement. The changes in monoamine levels in the brain of these mice were determined. There was a significant loss of dopamine with greatly increased dopamine turnover in the neostriatum 7 to 29 days after infection. These effects were specific for dopaminergic neurons since minimal changes were found in neostriatal norepinephrine and serotonin even though serotonin turnover was increased. Changes in monoamine metabolism were not limited to the neostriatum. There were reduced levels of serotonin and norepinephrine with increased serotonin turnover in the cerebellum. One year after infection, dopamine metabolism had returned to near normal levels, but many of the movement disorders persisted. Specific changes in neurochemistry did not always appear to correspond with these impairments. Nevertheless, these data are similar to those reported in MPTP treated BALB/c mice.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

Evaluation of a measurement strategy for Parkinson's disease: assessing patient health-related quality of life.

This study evaluated the feasibility and psychometric properties of self-completed and telephone interview versions of a patient health-related quality-of-life (HQL) questionnaire for Parkinson's disease that included the SF-36 Health Survey (SF-36), the Parkinson's Disease Questionnaire (PDQ-39), and the Medical Outcomes Study Sexual Function Survey. Parkinson's disease patients (n = 150) completed the questionnaire twice: once at the study site and once over the telephone in a randomized order. Ninety-four percent of enrolled patients completed the first HQL assessment and 88% completed both assessments. Cronbach's alpha exceeded 0.70 for all scales except for the self-completed PDQ-39 Social Support subscale (0.57) and the telephone interview PDQ-39 Social Support (0.60) and Cognitions (0.67) subscales and the SF-36 General Health (0.60) and Social Function (0.61) subscales. There were no statistically significant differences in mean HQL scale scores across the two modes of administration. Mean scores for 3 of the PDQ-39 subscales and the Summary Index were significantly poorer (p < 0.05) for patients at later clinical stages. Similarly, patients with dyskinesias reported significantly poorer scores for 4 of the PDQ-39 subscales and the Summary Index and patients with self-reported comorbidities reported poorer SF-36 Physical Function and General Health subscale scores than patients without dyskinesias and comorbidities, respectively. This study suggests that the self-completed and telephone interview versions of the patient HQL questionnaire are feasible and valid for future clinical trial applications.

Aged↗
PubMed2000

L-DOPA does not enhance hydroxyl radical formation in the nigrostriatal dopamine system of rats with a unilateral 6-hydroxydopamine lesion.

The debate about the toxicity of L-DOPA to dopaminergic neurons has not been resolved. Even though enzymatic and nonenzymatic metabolism of L-DOPA can produce hydrogen peroxide and oxygen free radicals, there has been controversy as to whether L-DOPA generates an oxidant stress in vivo. This study determined whether acute or repeated administration of L-DOPA caused in vivo production of hydroxyl radicals in striatum and other brain regions in rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal projections. Salicylate trapping combined with in vivo microdialysis provided measurements of extracellular 2,3-dihydroxybenzoic acid (2,3-DHBA) in striatum following L-DOPA administration systemically (100 mg/kg, i.p.) or by intrastriatal perfusion (1 mM, via the microdialysis probe). Tissue concentrations of 2,3-DHBA and salicylate were also measured in striatum, ventral midbrain, and cerebellum following repeated administration of L-DOPA (50 mg/kg, i.p., once daily for 16 days). In each instance, treatment with L-DOPA did not increase 2,3-DHBA concentrations, regardless of the nigrostriatal dopamine system's integrity. When added to the microdialysis perfusion medium, L-DOPA resulted in a significant decrease in the striatal extracellular concentration of 2,3-DHBA. These results suggest that administration of L-DOPA, even at high doses, does not induce hydroxyl radical formation in vivo and under some conditions may actually diminish hydroxyl radical activity. Furthermore, prior damage to the nigrostriatal dopamine system does not appear to predispose surviving dopaminergic neurons to increased hydroxyl radical formation following L-DOPA administration. Unlike L-DOPA, systemic administration of methamphetamine (10 mg/kg, s.c.) produced a significant increase in the concentration of 2,3-DHBA in striatal dialysate, suggesting that increased formation of hydroxyl radicals may contribute to methamphetamine neurotoxicity.

Animals↗
PubMed2000

New drugs for the treatment of Parkinson's disease.

Since the introduction of levodopa to treat Parkinson's disease (PD), several new therapies have been directed at improving symptom control, which can decline after a few years of levodopa therapy. Dopaminergic agents can serve as adjuncts or as alternatives to levodopa. In addition, a new class of drugs, catechol-O-methyltransferase inhibitors, can extend the duration of levodopa action. Although surgical options such as pallidotomy offer improvement of parkinsonism beyond the realm of pharmacologic treatment, judicious administration of drugs in combination can generally solve most problems of PD.

Antiparkinson Agents↗
PubMed2000

The challenge of managing mild Parkinson's disease.

Clinicians have a number of options when diagnosing and managing Parkinson's disease. The decision to start pharmacotherapy often depends on the particular needs of the patient and careful weighing of possible benefits, cost, and adverse outcomes. Even mild parkinsonism may require the input of a specialist to obtain the best results.

Antiparkinson Agents↗
PubMed1999

Measurement of acute phase proteins in the rat brain: contribution of vascular contents.

A localized acute phase response occurs in the brain in Alzheimer's disease. Acute phase proteins have previously been measured in brain homogenates to quantify this response. The extent to which measurements of these proteins reflect brain parenchymal contents, as opposed to vascular contents, is unknown. In this study, the acute phase proteins ceruloplasmin (CP), complement factor 3 (C3), haptoglobin (HP), and albumin were measured in regional brain homogenates from phosphate buffered saline-perfused and sham-perfused rats (n = 7-9/group). Interleukin 1-beta (IL1-beta) and copper were also measured. Mean CP, C3, HP, and albumin concentrations in perfused specimens decreased by 94%, 88%, 90%, and 81% vs. sham-perfused specimens (all p < 0.001), while IL1-beta and copper were unchanged. These results suggest that acute phase protein measurements in brain homogenates reflect primarily vascular contents. However, IL1-beta and copper concentrations in brain homogenates are minimally influenced by vascular contents.

Acute-Phase Proteins↗
PubMed1998

Clozapine use in Parkinson's disease: a retrospective analysis of a large multicentered clinical experience.

We conducted a multicentered, retrospective review of clozapine's (CZP) effects on a range of psychiatric, sleep, cognitive, motor, and sensory disorders in Parkinson's disease (PD). Therapeutic outcomes and adverse events were compared with varying prescribing practices at participating sites. The medical records of 172 consecutive PD patients treated with CZP at four movement disorder clinics were reviewed. Low-dose CZP improved psychiatric symptoms of psychosis, anxiety, depression, hypersexuality, sleep disturbance, and akathisia. Tremor, torticollis, limb dystonia, and pain showed modest rates of improvement. Twenty-three percent of patients withdrew as a result of adverse events or treatment failure. Inpatient CZP initiation did not improve therapeutic efficacy, or reduce adverse events or the withdrawal rate. Low-dose CZP in the outpatient setting is generally an effective and well-tolerated treatment for many of the psychiatric, sleep, motor, and sensory disturbances common to late-stage PD.

Aged↗
PubMed1998

Conjugate eye deviations as dyskinesias induced by levodopa in Parkinson's disease.

Involuntary upward and lateral eye movements are described in two Parkinson's disease patients who also experience levodopa-induced choreoathetoid limb movements simultaneously. These brief deviations of gaze represent a rare ocular manifestation of dyskinesia and are similar to oculogyric movements resulting from other causes.

Adult↗
PubMed1998

Altered guanosine and guanine concentrations in rabbit striatum following increased dopamine turnover.

The significance of guanine nucleotides and nucleosides in neurodegenerative disorders is suggested by recent reports that these molecules enhance neurite branching and astrocyte proliferation. The objective of this study was to investigate the influence of increased dopamine metabolism, produced by 5-day treatment of rabbits with reserpine (2 mg/kg) or levodopa (LD) (50 mg/kg), on striatal concentrations of guanosine, guanine, and their metabolites. Reserpine treatment decreased striatal guanosine by 41% and increased guanine by 50%, while LD decreased guanosine by 48% (all p < 0.01 vs. vehicle-treated controls). LD also increased guanine by 22% (not statistically significant). Xanthine and uric acid concentrations were unchanged. Because of the neurotrophic properties of guanosine and guanine, changes in striatal concentrations of these purines secondary to increased dopamine (DA) turnover may have relevance for survival of remaining dopaminergic neurons in Parkinson's disease (PD).

Animals↗
PubMed1998

Time-dependent effects of levodopa on regional brain dopamine metabolism and lipid peroxidation.

Levodopa treatment in Parkinson's disease has been suggested to contribute to disease progression through free radical generation. We compared the time course of levodopa-induced dopamine metabolism, and the resulting oxidative stress, between rat brain regions with varying dopaminergic innervation. At 1, 4, 8, and 12 h after levodopa administration (100 mg/kg), dopamine, dihydroxyphenylacetic acid, and homovanillic acid were measured in striatum and ventral midbrain, regions containing marked dopaminergic innervation, and in prefrontal cortex and cerebellum, which possess little dopaminergic innervation. Malondialdehyde, a marker of oxidative stress, was measured in additional animals. The return of dopamine and its metabolites to control concentrations tended to be slower (by 3-8 h) in cerebellum and prefrontal cortex than in dopaminergic regions. Malondialdehyde concentrations were decreased (p < 0.05) in ventral midbrain 8 h posttreatment, but increased in cerebellum 12 h posttreatment. We concluded that levodopa increases dopamine metabolism in nondopaminergic as well as dopaminergic regions, with delayed clearance of dopamine and its metabolites in nondopaminergic regions. The slower return of dopamine to control levels in nondopaminergic regions may be relevant to some of the side effects of levodopa. No support was found for the hypothesis that levodopa treatment induces oxidative stress.

3,4-Dihydroxyphenylacetic Acid↗