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Biomedical subjects

M D Muenter

Publications and source records attributed to M D Muenter.

At least 19 recordsLinked to original sources
PubMed1992

Dopamine agonist treatment of fluctuating parkinsonism. D-2 (controlled-release MK-458) vs combined D-1 and D-2 (pergolide)

Adjunctive treatment with the very potent and selective dopamine D-2 agonist MK-458 (controlled-release formulation) improved the control of parkinsonism in patients with fluctuating responses to levodopa therapy (with carbidopa). We subsequently switched patients to adjunctive treatment with pergolide, a less potent D-2 agonist. Pergolide therapy controlled parkinsonism more effectively than controlled-release MK-458. Unlike MK-458, pergolide mesylate also has D-1 agonist properties, apparently accounting for its greater antiparkinsonism efficacy. Adjunctive treatment with controlled-release MK-458 elicited less choreiform dyskinesias than either pergolide adjunctive therapy or therapy with carbidopa-levodopa alone; this finding suggests that D-1 receptor stimulation contributes to the elicitation of medication-induced chorea. The highest doses of controlled-release MK-458 resulted in paradoxical freezing of gait in almost one third of patients. This finding suggests that gait freezing, common in untreated parkinsonism, can also be elicited by excessive D-2 stimulation.

Adult↗
PubMed1991

An unusual cause of recurrent chorea.

Recurrent chorea is described in a 61-year-old woman who had had chorea gravidarum when she was younger. The recurrent chorea appeared to be induced by a topical vaginal cream that contained conjugated estrogen. This case is consistent with the existence of a recurrent syndrome of hormone-induced chorea. The effect of estrogen on the basal ganglia is complex and not fully understood.

Administration, Intravaginal↗
PubMed1991

Treatment of essential tremor with methazolamide.

We treated 28 patients (16 women and 12 men) who had essential tremor with methazolamide. Their median age was 69 years (range, 34 to 89 years), and the median duration of tremor was 16 years (range, less than 1 to 69 years). Fifteen cases were familial and 13 were sporadic. Improvement in 10 patients who continued taking the drug ranged from moderate to complete relief. In addition, four patients had marked improvement and two had moderate improvement but discontinued use of the drug because of side effects. Five patients with a mild response and seven with no response also discontinued methazolamide therapy. The maximal mean daily dose was 203 mg for all patients and 129 mg (maintenance dose) for the patients who continued taking the drug. Side effects consisted primarily of somnolence, nausea, epigastric discomfort, anorexia, paresthesias, and numbness. No aplastic anemia was noted in any of the patients. The median duration of follow-up was 6 months (range, 10 weeks to 29 months). The therapeutic effect seemed unrelated to a family history of tremor, the effect of alcohol, or the responsiveness to propranolol or primidone. Methazolamide may be an effective drug in the treatment of some patients with essential tremor, particularly those with head and voice tremor.

Adult↗
PubMed1991

Parkinson's disease monotherapy with controlled-release MK-458 (PHNO): double-blind study and comparison to carbidopa/levodopa.

The potent and selective dopamine D-2 agonist, MK-458 [PHNO; (+)-4-propyl-9-hydroxynaphthoxazine] was administered as monotherapy to nine patients with Parkinson's disease in a double-blind, placebo-controlled 12-week investigation; ten other patients were randomized to placebo. MK-458 was formulated as a controlled-release preparation, using a hydroxypropyl methylcellulose-lactase (HPMC) matrix. Patients receiving MK-458/HPMC improved on a variety of measures of parkinsonism, compared to their baseline scores; in contrast, only trivial improvement was seen within the placebo group. We subsequently compared the anti-Parkinson response to MK-458/HPMC with the response to chronic carbidopa/levodopa monotherapy in an open label trial. Carbidopa/levodopa improved parkinsonism to a significantly greater degree than MK-458/HPMC. Doses of MK-458 used in these studies (up to 60 mg per day) were substantially higher than those in previously reported preliminary studies of this medication. We conclude that monotherapy with MK-458/HPMC results in a significant anti-Parkinson effect; however, the response falls short of that seen with carbidopa/levodopa.

Adult↗
PubMed1990

MAO and L-dopa treatment of Parkinson's disease.

The aim of this study was to determine whether there were differences in the oxidative deamination of dopamine in patients with Parkinson's disease who demonstrated a long-duration response (LDR) to treatment with dopa and carbidopa and in patients who demonstrated only a short-duration response (SDR) to the drugs. The patients who demonstrated LDR had received dopa and carbidopa for a shorter time (3.4y) than had the SDR patients (9.5y). The concentrations of dopamine and 3-methoxytyramine and their deaminated metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid were measured in 24-h urine samples collected from patients in both groups. The ratios of homovanillic acid to 3-methoxytyramine and dopamine were greater in SDR than in LDR patients suggesting increased oxidative deamination of dopamine in this group. Increased oxidative deamination could be caused by an increase in MAO activity as Parkinson's disease progresses or by the treatment with L-dopa.

Aged↗
PubMed1990

An examination of male-female differences in progression and mortality of Parkinson's disease.

We conducted disability and mortality studies to determine if the male preponderance usually found in Parkinson's disease (PD) was reflected in different courses of the diseases in the 2 sexes. We analyzed longitudinal disability score in 47 men and 23 women with PD followed for 6 years at UCLA. We found no significant differences between the sexes in mean disability scores in any of the 6 years. Mean dopa dosage was significantly higher in men, possibly reflecting their generally larger body mass. Choreoathetosis, dementia, or other side effects did not differ between the 2 groups. We obtained observed to expected mortality ratios in 239 men and 132 women followed for 3,831 person-years from records of 4 medical centers. Using the sex-specific US Life Tables to calculate expected mortality, we found the observed to expected ratio for the men was 1.7457 and for the women 2.4740, a significantly greater excess in female mortality. Analyses of mortality using tables which are not sex-specific will fail to uncover the decreased longevity in women with PD. We conclude that, despite the male preponderance in PD, men and women acquire it at the same age, have the same progression and duration of disease, and die at the same age; whereas, in the general population, women have a longer life expectancy than men. It is not known what factors protect women from incurring PD and what lowers their life expectancy to that of men when they do have the disease.

Disability Evaluation↗
PubMed1989

Effect of age at onset on progression and mortality in Parkinson's disease.

We examined longitudinal disability scores in 54 patients with Parkinson's disease followed for 6 years at UCLA. We sorted data into 3 groups based on age at onset of symptoms: group A, onset under 50 years; group B, 50 to 59 years; group C, 60 years or older. There were no significant differences between groups initially. All 3 groups improved dramatically when levodopa was given, but group A showed significantly less disability in years 4, 5, and 6 than did group C. The groups did not differ with respect to side effects. To determine if age at onset affected mortality, we sorted records from 4 geographically diverse centers into the same 3 groups. Results on 359 patients followed for 3,314 person-years, covering a period of 17 years after onset of symptoms, showed that group A had the most favorable observed-to-expected mortality ratio, 1.82, compared with 2.17 and 2.20 for groups B and C respectively, but the difference was not statistically significant. Results from the disability analyses indicate that patients with onset of Parkinson's disease under 50 years of age may have a more favorable prognosis than those whose symptoms begin in later years.

Aging↗
PubMed1988

Epidemiology of focal and generalized dystonia in Rochester, Minnesota.

The epidemiology of generalized and focal dystonias was investigated in the Rochester, Minnesota, population over the period 1950-1982. The crude incidence of generalized dystonia was 2 per million persons per year, and for all focal dystonias combined, 24 per million per year. The crude prevalence rate was 34 per million persons for generalized dystonia and 295 per million persons for all focal dystonias. Torticollis was the most common focal dystonia; essential blepharospasm, oromandibular dystonia, spasmodic dysphonia, and writer's cramp were less common and had roughly equal incidence and prevalence rates.

Adolescent↗
PubMed1988

Controlled-release Sinemet (CR-4): a double-blind crossover study in patients with fluctuating Parkinson's disease.

Patients with moderate to advanced Parkinson's disease may have prominent levodopa-related motor fluctuations. In a double-blind crossover study, we compared the anti-Parkinson effects of standard Sinemet with a controlled-release formulation (Sinemet CR-4) in 23 patients with short-duration responses to standard Sinemet. With Sinemet CR-4, approximately half the patients who completed the study displayed a prolongation of their "on" response (optimal response to treatment), as assessed by monitoring individual drug-response cycles. A few patients experienced prolonged delays before the peak anti-Parkinson response developed to Sinemet CR-4. End-of-dose "wearing off" was favorably affected by Sinemet CR-4, but patients still had unpredictable "off" (parkinsonian) periods. Subjective ratings of Sinemet CR-4 varied, and 39% of patients who completed the study actually preferred standard Sinemet to the new formulation. We conclude that Sinemet CR-4 may benefit some patients with Parkinson's disease with a short-duration response to standard Sinemet; however, not all patients found it preferable to the standard formulation.

Activities of Daily Living↗
PubMed1988

Treatment of Parkinson's disease with pergolide: a double-blind study.

Pergolide is a potent dopamine agonist and is known to have anti-Parkinson properties. We administered pergolide to patients with suboptimal control of Parkinson's disease who had a short-duration response to carbidopa-levodopa in a 6-month, double-blind study. Pergolide added to the carbidopa-levodopa regimen resulted in both subjective and objective improvement in comparison with placebo. In patients who tolerated pergolide, the median time spent in the "off" (parkinsonian) state was reduced from 5.0 to 2.2 hours daily (compared with a 0.3-hour reduction in the placebo group). These patients were able to decrease the median frequency of carbidopa-levodopa dosage from 7.5 to 5.0 doses daily (no change in the placebo group). Prolongation of the "on" response (optimal response to treatment) to single doses of drugs was corroborated by monitoring of the patients' Parkinson response cycle. The peak response was also improved in most patients. Of 25 patients randomized to the pergolide group, 7 were unable to tolerate this drug; confusion or hallucinations occurred in 4 of these patients, and chest pain, leukopenia, and nonspecific dizziness, respectively, developed in the other 3. All adverse events were reversible with reduction of the dose or discontinuation of the pergolide regimen. In conclusion, patients with Parkinson's disease who experience clinical fluctuations with carbidopa-levodopa may be helped by the addition of pergolide to the therapeutic regimen.

Activities of Daily Living↗
PubMed1988

Pergolide: long-term use in Parkinson's disease.

Previous short-term studies have shown that the dopamine agonist pergolide improves control of Parkinson's disease when used in conjunction with carbidopa-levodopa (Sinemet). We assessed the long-term outcome (2 1/2- to 3-year follow-up) in patients with Parkinson's disease who participated in our previous pergolide double-blind trial and were subsequently switched to open-label pergolide therapy. Of 41 evaluable patients who began pergolide therapy, 10 (24%) experienced sustained substantial benefit that persisted to the end of this investigation. A total of 23 patients (56%) remained on pergolide therapy and, as a group, had considerable improvement over baseline at 2 1/2 to 3 years on the basis of several measurements of efficacy. A tendency toward deterioration could be reversed in many patients by larger or more frequent doses of carbidopa-levodopa; nevertheless, all but four patients were still taking the same dose or less of carbidopa-levodopa at the end of this study as at the onset. Patients with the best initial response to pergolide seemed most likely to experience long-term benefit. Confusion and hallucinations were the side effects most likely to necessitate discontinuation of pergolide. Symptoms suggestive of dose-related angina pectoris occurred in four patients in the open-label phase and two patients in the earlier double-blind phase (13% of patients who started pergolide therapy); these symptoms were easily controlled by dose reduction or discontinuation of pergolide, without sequelae. Dose-related leukopenia developed in one patient.

Aged↗
PubMed1988

Deprenyl in the treatment of symptom fluctuations in advanced Parkinson's disease.

Deprenyl, a selective inhibitor of monoamine oxidase, type B, which is free of the "tyramine effect," may ameliorate symptom fluctuations in advanced Parkinson's disease (PD). We randomized 96 patients with marked symptom fluctuations at three centers to receive either deprenyl 5 mg b.i.d. or placebo in parallel fashion in addition to a previously optimized levodopa/carbidopa (Sinemet) regimen. Disability was recorded hourly at home by patients 3 days weekly during the 2-week baseline and the 6-week treatment period. Disability during the "on" state was assessed each week by examination. Mean hourly self-assessment of gait improved in 28 of 50 patients (56%) receiving deprenyl (mean degree of improvement 0.25 points on a 0-2 scale) and in 14 of 46 (30.4%) taking placebo (mean 0.15). Mean hourly overall symptom control improved in 29 (58%) taking deprenyl (mean 0.34) and in 12 (26.1%) taking placebo (mean 0.15) (p less than 0.01 for each parameter). No significant improvement occurred in the objective quality of the "on" state with deprenyl. Mean daily Sinemet dosage decreases were 17% in the deprenyl group and 7% in the placebo group. Adverse effects included nausea, light-headedness, dyskinesias, and hallucinations, all of which abated after the Sinemet dose was reduced. We conclude that deprenyl is of moderate benefit in a majority of patients with symptom fluctuations complicating PD and is generally well tolerated.

Adult↗
PubMed1988

PHNO [(+)-4-propyl-9-hydroxynaphthoxazine]: a new and effective anti-Parkinson's disease agent.

PHNO [(+)-4-propyl-9-hydroxynaphthoxazine] is a chemically novel and highly potent dopamine (D2) receptor agonist without D1 activity. It had significant antiparkinsonism effects when used as open-label monotherapy in ten patients who were Hoehn and Yahr stage 2 or 3. The standard formulation of PHNO produced a 3- to 4-hour therapeutic effect in most patients; the response to the time-release formulation lasted up to 10 hours. Side effects were similar to those of other dopamine agonists but dyskinesia was seen in only one patient.

Adult↗
PubMed1987

Multi-center study of Parkinson mortality with early versus later dopa treatment.

Four geographically diverse centers provided data on mortality in 359 patients with Parkinson's disease, the majority of whom began dopa treatment during the early experimental trials of 1968 to 1970. Patients were classified into three groups based on the duration of symptoms prior to starting dopa treatment: Group 1, 1 to 3 years; Group 2, 4 to 6 years; Group 3, 7 to 9 years. After 15 years of treatment and 3,689 person-years of observation, Group 1 had an observed-to-expected mortality ratio of 1.43; Group 2, 2.44; and Group 3, 2.95 (p less than 0.05). This result confirmed that increased duration of disease was associated with increased mortality risk. To examine the effect of the time of initiation of dopa treatment, duration of disease was held constant at 17 years for all three groups. Observed-to-expected mortality ratios were 1.43 for Group 1; 2.66 for Group 2; 2.63 for Group 3. This statistically significant advantage for Group 1 (p less than 0.0001) led to the conclusion that early treatment with dopa has a beneficial effect on life expectancy. After 17 years of disease, causes of death in Group 1 were less likely (p = 0.027) to be due to Parkinson's disease than was found in the other groups.

Aged↗
PubMed1986

Pharmacotherapy: problems and practices.

Treatment of Parkinson's disease is not difficult in the early stages of the disease; a therapeutic regimen of carbidopa-levodopa or possibly, a combination of carbidopa-levodopa and bromocriptine, provides the best therapeutic results. There is no reason to withhold carbidopa-levodopa therapy early in the disease. During the more advanced stages of the disease, in addition to meticulous titration of carbidopa-levodopa, the administration of a dopamine agonist (such as bromocriptine), amantadine, or an anticholinergic agent may be required in an attempt to smooth the therapeutic effect. All of these drugs, with the exception of amantadine, require small initial doses with subsequent cautious increases in dosage. Mental side effects are less likely to occur with carbidopa-levodopa therapy than with any of the other drugs.

Amantadine↗
PubMed1977

Patterns of dystonia ("I-D-I" and "D-I-D-") in response to l-dopa therapy for Parkinson's disease.

The clinical, biochemical, and pharmacologic responses to L-dopa were studied in 87 patients with Parkinson's disease. Eleven of the 87 patients had a long-duration response, 39 had a short-duration response, and 37 had a combination of both. Thirty-four of the 39 patients with short-duration response to L-dopa experienced a consistent and reproducible sequence of clinical and biochemical events after each dose, characterized by improvement of parkinsonism and a single phase of dystonia occurring during or shortly after the peak of dopa concentration in plasma and during maximal clinical improvement. We have called this the I-D-I- response, for Parkinsonism-Improvement-Dystonia-Improvement-Parkinsonism. The remaining five patients all had the onset of the disease at an unusually young age and showed a distinctly different response pattern consisting of a first phase of dystonia, before there was any improvement, followed by a phase of improvement without dystonia and then by a second phase of dystonia before the abrupt return of parkinsonism. We have called this the D-I-D response, for Parkinsonism-Dystonia-Improvement-Dystonia-Parkinsonsim. Dystonia occurs in the D-I-D- response when the concentration of dopa in plasma passes through a critical but relatively low level, whereas it remains absent as long as the concentration of dopa remains above that level. In the I-D-I- response, dystonia is avoided by keeping the plasma concentration of dopa low, in the D-I-D- response by keeping it high. It is postulated that in the D-I-D response postsynaptic depolarization blockade due to supramaximal stimulation of the neuronal system mediating dystonia occurs, whereas in the I-D-I response the postsynaptic members of the same neuronal population respond with excitation but not with depolarization blockade.

Dose-Response Relationship, Drug↗
PubMed1975

Effect of L-DOPA on endogenous histamine metabolism.

To estimate the effect of long-term administration of L-3,4-dihydroxyphenylalanine (L-Dopa) on methylation of compounds not formed from it, the urinary excretion of histamine and its methylated metabolites was studied in rats and guinea pigs fed L-Dopa in their diets and in patients with Parkinson's disease being treated with L-Dopa. In the guinea pigs, but not in the rats, L-Dopa administration decreases excretion of histamine and of its methylated metabolites, methylhistamine and 1-methylimidazole-4-acetic acid. Because excretion of 1-methylimidazole-5-acetic acid, which comes from the diet and is not a metabolite of histamine, was unaffected by the L-Dopa treatment, the decreases were due to a specific effect of L-Dopa on histamine metabolism. When compared to normal control subjects, patients with Parkinson's disease excreted less histamine and methylhistamine, both before and during treatment with L-Dopa. Administration of the peripheral aromatic L-amino acid decarboxylase inhibitor, L-alpha-methyldopa hydrazine (MK 486), decreased urinary excretion of histamine markedly. Neither L-Dopa nor MK 486 appeared to influence excretion of the imidazoleacetic acids in the patients. The results suggest that L-Dopa may decrease histamine formation or release in some species but that it does not influence histamine methylation.

Acetates↗