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R F Pfeiffer

Publications and source records attributed to R F Pfeiffer.

At least 55 records · Page 3Linked to original sources
PubMed1994

Distribution of zinc metallothionein I mRNA in rat brain using in situ hybridization.

Metallothionein (MT) isoforms I and II were first identified and characterized in our laboratories in several regions of brain, in hippocampal neurons in primary culture, and in retinoblastoma and neuroblastoma cell lines. In this study, by having employed the MT-I cDNA as a probe, we sought to gain additional insight about the function of MT by discerning the regional distribution of its mRNA. Northern blot analyses of brain mRNA revealed that the administration of zinc enhanced dramatically MT-I mRNA (570 bp). The in situ hybridization study revealed that MT-I mRNA was located in several areas of brain, with the highest concentrations found in the cerebellum, hippocampus, and ventricles. The results of these studies are interpreted to suggest that zinc enhances the synthesis of MT mRNA and MT in turn may participate in zinc associated functions in neurons.

Animals↗
PubMed1994

Distribution of cholinergic and dopaminergic receptors in rainbow trout pineal gland.

The involvement of multiple receptors in modulating the function of the pineal gland was investigated by searching for dopaminergic and cholinergic receptors in trout pineal gland. Dopamine D1 and D2 receptors were measured using [3H]SCH23390 and [3H]spiperone, respectively. Muscarinic and nicotinic cholinergic receptors were measured using quinuclidinyl benzilate ([3H]QNB) and [3H]methylcarbamyl choline, respectively. High-affinity choline uptake sites were measured using [3H]hemicholinium-3. The distribution of dopaminergic receptors varied throughout the pineal gland in that the density of D2 receptors, which was higher than that of D1 receptors, was most abundant in the distal region, exhibiting a value of 112 +/- 17 fmol/mg tissue. The distribution of both muscarinic and nicotinic receptors was uniform throughout the pineal gland. However, the highest value for the high-affinity choline transporter (106 +/- 17 fmol/mg tissue) occurred in the proximal portion of the trout pineal gland. The results of these studies indicate that the pineal gland should not be viewed as a homogeneous tissue possessing identical density of various receptors. Furthermore, these results, along with previous data, are interpreted to suggest that different regions of pineal gland may indeed possess unique functions.

Animals↗
PubMed1994

Characterization of swallowing and defecation in Parkinson's disease.

UNLABELLED: Despite the high prevalence of Parkinson's disease, the pathophysiology of its gastrointestinal symptoms remains poorly understood. OBJECTIVES: to evaluate swallowing and defecatory function in patients with Parkinson's disease and age- and sex-matched controls and to correlate objective findings with subjective symptoms. METHODS: The following studies were performed on 13 patients with Parkinson's disease and seven controls: extrapyramidal function assessment, gastrointestinal symptom survey, videoesophagram, colon transit study, defecography, and anorectal manometry. RESULTS: Abnormal salivation (frequency, %, control vs. Parkinson's disease: 14 vs. 77, p < 0.05), dysphagia (14 vs. 77, p < 0.05), constipation (14 vs. 31, p < 0.05), and defecatory dysfunction (29 vs. 77, p < 0.05) were more common among Parkinsonian patients. However, videoesophagographic abnormalities were equally common in both groups. Colon transit time was significantly prolonged in the Parkinson's disease group. Altered puborectalis function was noted on defecography in 31% of Parkinson's disease subjects, but in none of the controls (p < 0.05). Anorectal manometry identified several abnormalities in the Parkinson's disease group, which included decreased basal anal sphincter pressures, prominent phasic fluctuations on squeeze, and a hyper-contractile external sphincter response to the rectosphincteric reflex. Many patients exhibited both slow transit and manometric abnormalities, and symptoms were poor predictors of test results. CONCLUSION: In this group of patients with mild to moderate Parkinson's disease, videoesophagographic abnormalities were not confined to the patients with Parkinson's disease. Studies of colonic and anorectal function, in contrast, identified a number of abnormalities. Therefore, colonic and anorectal dysfunction appears to be an early gastrointestinal manifestation of Parkinson's disease, and may represent the direct involvement of the gut by this disease process.

Aged↗
PubMed1993

Defecatory function in Parkinson's disease: response to apomorphine.

We evaluated the effects of the dopaminergic agent apomorphine on defecation and anorectal function in patients with Parkinson's disease (PD). A gastrointestinal symptom survey, extrapyramidal assessment, defecating proctogram, and anorectal manometric study were performed in 8 subjects with PD. Basal studies showing abnormalities were repeated following apomorphine administration. Prior defecographic abnormalities were normalized following apomorphine injection in 1 of 3 subjects and significant improvements in manometric parameters were observed in all 5 subjects who underwent repeat anorectal manometry. We conclude that apomorphine can correct anorectal dysfunction in PD, and that these abnormalities may be a consequence of dopamine deficiency secondary to the PD process. These findings may also have therapeutic implications.

Aged↗
PubMed1993

Gastrointestinal symptoms in Parkinson disease: 18-month follow-up study.

In a recent study we identified abnormal salivation, dysphagia, nausea, constipation, and defecatory dysfunction as those gastrointestinal (GI) symptoms associated with Parkinson disease (PD) and characterized their relationship to PD severity and therapy. In this study, we re-evaluated these symptoms and their relationship to parameters of PD 18 months later. Sixty-six percent of the original participants responded. Over the 18 months, 68% of originally untreated PD subjects commenced anti-PD therapy. Abnormal salivation, dysphagia, nausea, constipation, and defecatory dysfunction were again identified as those GI symptoms more common in PD. Constipation increased both in severity and frequency. Comparison of GI symptom scores and parameters of PD dysfunction failed to reveal significant progression of either GI symptomatology or PD dysfunction, or the development of new GI symptoms over the 18-month period. This study validates our GI dysfunction assessment system and confirms abnormal salivation, dysphagia, nausea, constipation, and defecatory function as those GI symptoms truly associated with PD. A direct relationship between PD and its related GI symptoms is again supported.

Aged↗
PubMed1993

The effects of 6-hydroxydopamine and oxidative stress on the level of brain metallothionein.

Oxidative stress, resulting either from excess generation or reduced scavenging of free radicals, has been proposed to play a role in damaging striatal neurons in Parkinson's disease. Since metallothionein is able to regulate the intracellular redox potential, we have undertaken a group of experiments to see whether or not 6-hydroxydopamine, which generates free radicals and is toxic to dopaminergic neurons, could alter the level of zinc and metallothionein. 6-Hydroxydopamine (8 micrograms in 4 microliters 0.02% ascorbic acid) reduced the level of zinc and metallothionein in the striatum but not other brain regions tested. Dopamine plus selegiline increased the synthesis of metallothionein in Chang cells as judged by enhanced incorporation of [35S]cysteine into metallothionein. The effect of dopamine was selective, in that dopamine could not stimulate the synthesis of metallothionein in neuroblastoma IMR-32 cells, which are devoid of dopaminergic receptors. The effect of dopamine in stimulating the synthesis of metallothionein was similar to that of zinc, known to generate the synthesis of metallothionein, and to that of H2O2 and FeS04, known to generate free radicals. The results of these experiments provide additional evidence that zinc or zinc metallothionein are altered in conditions where oxidative stress has taken place.

Animals↗
PubMed1993

Antiserum against neuropeptide Y enhances the nicotine-mediated release of catecholamines from cultured rat adrenal chromaffin cells.

A primary culture of chromaffin cells was prepared from adult rats and the stability of cell contents, NPY and catecholamines (CAs), during the culture was studied. The responsiveness of cultured chromaffin cells to NGF or secretagogues and the possible role of NPY on the CA secretion from cultured chromaffin cells were investigated. After plating of isolated cells, there was marked decrease in the cell content of CAs but a significant increase in the cell content of NPY. Though both NPY and CAs in the cultured cells were positively regulated by NGF, the results of this study seemed to suggest a differential regulation for NPY and CAs in the chromaffin cell. The cultured chromaffin cells secreted NPY and CAs in response to stimulation by nicotine. The nicotine stimulated secretion of CA was enhanced by the presence of IgG fraction, prepared from NPY antiserum, in the secretion medium. The results suggested that NPY was co-released with CAs from chromaffin cells and then acted as a modulator on CA secretion.

Adrenal Glands↗
PubMed1993

Purification and characterization of metallothionein and its activation of pyridoxal phosphokinase in trout (Salmo gairdneri) brain.

1. Brain metallothionein was isolated and purified for the first time from rainbow trout. 2. Brain metallothionein exhibited an elution volume (Ve/Vo) of 2.0, had a molecular weight of 6762 Daltons, and contained a zinc content of 9 micrograms/mg protein. 3. Brain pyridoxal phosphokinase was isolated and assayed for the first time in rainbow trout. 4. Zinc (0.20 microM) or zinc metallothionein (6-30 microM) stimulated the activity of brain pyridoxal kinase in a linear fashion. 5. The results of these studies are interpreted to suggest that in trout brain zinc metallothionein may participate in metabolism of vitamin B6 and formation of pyridoxal phosphate, the active coenzyme.

Animals↗
PubMed1992

Rapidly progressive autosomal dominant parkinsonism and dementia with pallido-ponto-nigral degeneration.

We describe a family with nearly 300 members over 8 generations with 32 affected individuals who have an autosomal dominant neurodegenerative disease characterized by progressive parkinsonism with dystonia unrelated to medications, dementia, ocular motility abnormalities, pyramidal tract dysfunction, frontal lobe release signs, perseverative vocalizations, and urinary incontinence. The course is exceptionally aggressive; symptom onset and death consistently occur in the fifth decade. Positron emission tomographic studies with [18F]6-fluoro-L-dopa (6FD) were performed in 4 patients and 7 individuals at risk for development of the disease. All affected subjects had markedly reduced striatal uptake of 6FD (p less than 0.001). All individuals at risk had normal striatal uptake, but high 6FD uptake rate constants were noted in 3 of the 7 studied. Autopsy findings revealed severe neuronal loss with gliosis in substantia nigra, pontine tegmentum, and globus pallidus, with less involvement of the caudate and the putamen. There were no plaques, tangles, Lewy bodies, or amyloid bodies. This kindred appears to represent a neurodegenerative disease not heretofore described. We propose the following name for this new genetic disease: autosomal dominant parkinsonism and dementia with pallido-ponto-nigral degeneration.

Adult↗
PubMed1992

Differential stimulation of hepatic and brain metallothioneins by ethanol.

Administration of ethanol induces the synthesis of hepatic metallothionein and metallothionein mRNA in the liver but not in the brain. Furthermore, ethyl alcohol, methyl alcohol and isopropyl alcohol enhance the synthesis of metallothionein in Chang cells but not in neuroblastoma IMR-32 cells in culture. The results of this study are interpreted to suggest that the mechanisms of synthesis of metallothionein and the utilization of essential metal nutrients in the brain and peripheral tissues are not identical.

1-Propanol↗
PubMed1992

Gastrointestinal dysfunction in Parkinson's disease: frequency and pathophysiology.

Although more extensive research is required to fully characterize the pathophysiology of the gastrointestinal symptoms in PD, much of the presently available data suggest that the primary PD process is the major factor in the etiology of gut dysfunction in this patient population. This may be mediated by both central and peripheral mechanisms. Involvement of the dorsal motor nucleus of the vagus might produce dysfunction of muscles controlling deglutition and esophageal motility, thereby leading to drooling, dysphagia, and gastroesophageal reflux. The presence of Lewy bodies, the primary neuropathologic finding in the CNS in PD, in the myenteric plexus of both the esophagus and colon suggests that the PD process may also affect the enteric nervous system and contribute to the development of esophageal dysmotility and constipation through this peripheral mechanism. Dopamine receptors have been identified in the lower esophageal sphincter and the esophageal body of animals. If similarly present in humans, involvement of this dopaminergic system could contribute to the development of dysphagia and nausea of PD. Constipation may reflect both peripheral involvement, indicated by Lewy bodies in the colonic myenteric plexus, leading to colonic inertia, and central mechanisms, leading to pelvic floor dysfunction.

Colon↗
PubMed1992

Genetic considerations in movement disorders.

Certain genetic aspects of the movement disorders, including parkinsonism, dystonia, ataxia, chorea, tics, and others, are reviewed. Clinical features, diagnostic techniques, and laboratory tests of newly recognized inherited syndromes are discussed. Progress in linkage analysis in several disorders is also presented.

Brain↗
PubMed1991

Epileptiform electroencephalographic abnormalities in liver transplant recipients.

We retrospectively studied patients who had undergone orthotopic liver transplantation and who also had electroencephalography to determine whether epileptiform changes were associated with a poor neurological outcome. Study groups were 36 patients who died after transplantation (141 electroencephalograms) and underwent neuropathological examination, 11 who died (18 electroencephalograms) but did not have autopsy, and a third group of 34 (62 electroencephalograms) who remained alive. Epileptiform activity was seen in electroencephalograms of 14 of the patients who died (11 from the autopsy group) and in 2 of those who remained alive. All had multiple epileptiform abnormalities and clinical or subclinical seizures. The incidence of epileptiform activity after orthotopic liver transplantation was fivefold higher in the nonsurvivors. Serious cerebral structural changes were found in 10 of the 11 patients who underwent autopsy. Epileptiform activity in the electroencephalograms of patients who had undergone orthotopic liver transplantation indicates a poor prognosis. It should alert the clinician to investigate further for potentially treatable causes.

Adolescent↗
PubMed1991

Gastrointestinal symptoms in Parkinson's disease.

We have investigated the prevalence of gastrointestinal (GI) symptoms in 98 individuals with Parkinson's disease (PD) and in a control group of 50. Seventy-nine of those with PD were being treated with dopaminergic medications and 19 were untreated. Those symptoms occurring more frequently in PD patients than in controls included abnormal salivation, dysphagia, nausea, constipation, and defecatory dysfunction. Except for defecatory dysfunction, symptoms did not correlate with treatment but instead correlated with disease severity. This suggests that the GI symptoms of PD reflect direct involvement in the GI tract by the primary disease process.

Aged↗
PubMed1991

CQA 206-291 in Parkinson's disease.

CQA 206-291, a mixed D1-D2 receptor agonist that also possesses dualistic dopamine antagonist-agonist properties, was investigated in a double-blind, placebo-controlled trial in individuals with Parkinson's disease of moderate severity. Significant improvement was noted in the treatment groups compared to the placebo group. Adverse effects were generally mild and transient. CQA appears to be an effective, well-tolerated agent in the treatment of Parkinson's disease. Nevertheless, because of laboratory-based toxicity concerns, CQA has been withdrawn from further human study and will not be developed clinically.

Activities of Daily Living↗
PubMed1991

Sinemet CR in Parkinson's disease.

Sinemet CR, a controlled release carbidopa/levodopa preparation, was compared to conventional carbidopa/levodopa in a double blind, placebo-controlled trial. Comparable clinical benefits and adverse effects were noted with the two medications. However significantly less frequent dosing was necessary with Sinemet CR.

Aged↗
PubMed1990

Dentatorubro-pallidoluysian atrophy of the myoclonus epilepsy type with posterior column degeneration.

Dentatorubro-pallidoluysian atrophy (DRPLA) has a variable clinical presentation but the pathology is routinely confined to cerebellifugal and pallidofugal systems. We present a case of DRPLA of the myoclonus epilepsy type in which prominent posterior column degeneration was added to the pathological picture. This case illustrates the concept that the neurodegenerative diseases can be a continuum of both clinical and pathological presentations.

Adult↗