Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several neurological conditions have been reported to be associated with peripheral or central deficits of olfactory system. In recent years particular emphasis has been placed on the early and severe olfactory impairment in Parkinson's disease (PD), in which limited neuropathological studies have revealed a marked dopaminergic deficit in the olfactory tubercles. Moreover, indirect evidence suggests that dysfunction of the dopaminergic pathways from mesencephalon to the piriform cortex may play a role in olfactory impairment in PD. A large number of clinical studies have reported that olfactory loss in idiopathic PD is bilateral, present in hemiparkinsonism, unrelated to the stage or clinical subtype of the disease, and independent of antiparkinsonian medication. In addition, major olfactory alterations have been reported in familial PD and dementia with Lewy bodies but not in progressive supranuclear palsy and essential tremor. These findings might stimulate further research targeted to determine the biological substrate of dissimilar olfactory performances in these movement disorders. The present review summarizes standardized procedures for the assessment of olfactory acuity (detection threshold), identification (multiple choice odor naming), discrimination (differentiation between similar/dissimilar odorants), and memory (recognition of a substance previously smelled). Specific suggestions concerning the psychometric and neuropsychological evaluation of PD patients are provided.
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PMID:Olfaction in Parkinson's disease: methods of assessment and clinical relevance. 1075 Nov 9

The olfactory system is one of the nonmotor systems severely affected in Parkinson's disease (PD). Olfactory dysfunction occurs early in the disease process, is independent of disease stage, duration, and treatment. However, olfactory dysfunction appears to be dependent on disease subtype. Olfaction is mildly impaired or preserved in most of the parkinsonism-plus syndromes (PPS). This provides a means of differential diagnosis between typical PD and PPS. Olfactory function is impaired also in familial forms of parkinsonism in which the genetic defect is known. In familial parkinsonism, olfactory function is impaired in both typical PD and PPS phenotypes. Olfactory dysfunction does not appear to be a manifestation of dopamine deficiency. Olfactory dysfunction is also associated with other neurodegenerative diseases such as Alzheimer's disease (AD), Huntington's disease (HD), as well as with normal aging. The neuropathological changes observed in the olfactory system in PD and other neurodegenerative diseases appear to be disease-specific, raising the possibility that olfactory dysfunction may be the result of a central rather than a peripheral process. The cellular and molecular mechanisms underlying olfactory dysfunction in PD and other neurodegenerative diseases remain unknown.
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PMID:Olfactory dysfunction in Parkinson's disease. 1078 34

Olfactory disorders in Alzheimer's disease and Parkinson's disease have been the topic of a large body of work over the last decades. Work devoted to olfactory disorders in Alzheimer's disease includes over 300 papers providing clinical and fundamental data. Anatomy studies in Alzheimer's disease have demonstrated a specific concentration of lesions in peripheral and central olfactory structures (senile plaques, neurofibrillary degeneration) as well as lesions in layers II and III of the entorhinal cortex. These neuropathological findings led to the development of the hypothesis that olfactory disorders in Alzheimer's disease would result from a toxic process. Observed olfactory deficits involve both identification and recognition of odors and detection thresholds. Nevertheless, patients with Alzheimer's disease rarely consult for sensorial deficits as the other signs of the disease predominate. Neuropathology data on the olfactory system are much more sparse in Parkinson's disease. Lewy bodies suggestive of Parkinson's disease have been observed in the olfactory bulb and pathways, but, unlike Alzheimer's disease, the olfactory disorders appear to be stable, changing little over time, as opposed to the evolution of neurological symptoms and cognition impairment. Clinicians should be aware that olfactory disorders are an integral part of Alzheimer's disease and Parkinson's disease. Screening for sensorial impairment however is a secondary objective in the context of these neurodegenerative diseases.
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PMID:[Olfactory disorders in Alzheimer's disease and in Parkinson's disease. Review of the literature]. 1085 62

In several neurodegenerative diseases, iron accumulates at sites of brain pathology. Since post-mortem examination cannot distinguish whether iron accumulation caused the damage or resulted from damage, it is necessary to manipulate iron in animal and tissue culture models to assess its causal role(s). However, only in models of Parkinson's disease and of global ischemia, iron deprivation (ID) or iron-chelators have been used to protect from damage. In these studies, documentation of microgliosis was not performed even though several lines of evidence converge to suggest that activation of microglia is an important source of oxidative stress. In the kainate model of epilepsy, we found that ID protected the olfactory cortex, thalamus and hippocampus and attenuated microgliosis, whereas iron supplementation to ID rats increased damage and microgliosis in the above regions. In the hilus of the hippocampal dentate gyrus, even though no cell loss was observed, ID attenuated microgliosis and iron-supplementation increased it. Thus there is a tight relationship between iron and microgliosis. In addition, iron+zinc supplementation dramatically increased damage to hippocampal CA1 whereas zinc supplementation alone had no effect. This study demonstrates an anatomically unique interaction of iron and zinc, which may lead to new insights to neurodegeneration in epilepsy.
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PMID:Iron involvement in neural damage and microgliosis in models of neurodegenerative diseases. 1087 37

Disorders of the sense of smell are receiving growing clinical as well as experimental attention. Indeed, several neurological conditions have been associated with peripheral or central deficits of the olfactory system. In recent years, particular emphasis has been attributed to the early and severe olfactory impairment in neurodegenerative diseases, such as Alzheimer's dementia and Parkinson's disease. Olfactory assessment has also been included in comprehensive pre- and post-surgical evaluations of temporal lobe epilepsy. Moreover, the request for standardized methods of olfactory evaluation by forensic and occupational medicine is greatly increasing. Despite this requirement, there is no agreement in the Italian neurological community on olfactory assessment. This lack prompted us to generate a battery of standardized tests capable of bypassing cross-cultural differences in olfactory assessment and to be potentially useful in the clinical as well as experimental settings. Procedures of assessment of olfactory acuity (detection threshold), identification (multiple choice odor naming), discrimination (differentiation between similar/dissimilar odorants) and memory (recognition of a substance previously smelled) are fully described. In order to control bias factors depending upon the nature of the investigated disorder and the applied olfactory tasks, a minimal complementary neuropsychological assessment is recommended.
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PMID:Assessing olfaction in the Italian population: methodology and clinical application. 1093 37

This review examines interactions in the mammalian central nervous system (CNS) between carnosine and the endogenous transition metals zinc and copper. Although the relationship between these substances may be applicable to other brain regions, the focus is on the olfactory system where these substances may have special significance. Carnosine is not only highly concentrated in the olfactory system, but it is also contained in neurons (in contrast to glia cells in most of the brain) and has many features of a neurotransmitter. Whereas the function of carnosine in the CNS is not well understood, we review evidence that suggests that it may act as both a neuromodulator and a neuroprotective agent. Although zinc and/or copper are found in many neuronal pathways in the brain, the concentrations of zinc and copper in the olfactory bulb (the target of afferent input from sensory neurons in the nose) are among the highest in the CNS. Included in the multitude of physiological roles that zinc and copper play in the CNS is modulation of neuronal excitability. However, zinc and copper also have been implicated in a variety of neurologic conditions including Alzheimer's disease, Parkinson's disease, stroke, and seizures. Here we review the modulatory effects that carnosine can have on zinc and copper's abilities to influence neuronal excitability and to exert neurotoxic effects in the olfactory system. Other aspects of carnosine in the CNS are reviewed elsewhere in this issue.
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PMID:Interactions between carnosine and zinc and copper: implications for neuromodulation and neuroprotection. 1095 Oct 99

Despite a long-lasting therapeutic use of L-DOPA in Parkinson's disease, doubts still remain concerning the possibility that chronic L-DOPA might accelerate the progression of this movement disorder. To address this point, in the present study we examined the effects of chronic L-DOPA administration either in intact or MPTP-treated parkinsonian mice. We produced an intermediate striatal dopamine loss by administering a low dose of MPTP (30 mg/kg); then, we treated mice chronically, for different time intervals, with a daily dose of L-DOPA (50 mg/kg). In particular, to study the time-course of the effects of L-DOPA on the recovery of nigrostriatal dopamine axons, mice were sacrificed at 5, 30, 60, and 90 days after a daily L-DOPA administration. To evaluate presynaptic integrity of the nigrostriatal pathway we measured dopamine, metabolite levels, and dopamine uptake sites. In the same animals, we measured striatal serotonin levels and we analysed monoamine content in the olfactory bulb. Administration of MPTP produced a neurotoxic effect, which fully recovered in 2-3 months. Daily L-DOPA administration did not modify this recovery process. Additionally, there was no significant effect of L-DOPA in intact mice, despite a slight decrease in striatal dopamine levels at 5 and 30 days. However, this effect was neither worsened nor reproduced by administering higher doses of L-DOPA (up to 400 mg/kg) for the same amount of time. These data rule out neurotoxic effects induced by prolonged L-DOPA administration, both in intact and MPTP-treated mice. Moreover, administration of L-DOPA does not change the recovery process which takes place after a nigrostriatal lesion.
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PMID:Time-course and dose-response study on the effects of chronic L-DOPA administration on striatal dopamine levels and dopamine transporter following MPTP toxicity. 1113 95

The main and accessory olfactory systems have received considerable attention on the part of scientists and clinicians during the last decade, largely because of (a) quantum advances in understanding their genetically expressed receptor mechanisms, (b) evidence that their receptor cells undergo neurogenesis and both programmed and induced cell death, and (c) important technical and practical developments in psychophysical measurement. The latter developments have led to the proliferation of standardized olfactory testing in laboratories and clinics, and to the discovery that smell loss is among the first signs of a number of neurodegenerative diseases, including Alzheimer's disease and idiopathic Parkinson's disease. Recent controversial claims that humans possess a functioning vomeronasal system responsive to "pheromones" has added further interest in intranasal chemoreception. This review focuses on recent progress made in understanding olfactory function, emphasizing transduction, measurement, and clinical findings.
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PMID:Olfaction. 1114 12

Olfactory dysfunction is a common finding in patients with Parkinson's disease (PD). As most studies reported on odor identification in more advanced and treated PD, we administered an odor detection, discrimination, and identification test to a heterogeneous, partly de novo, group of patients. Forty-one non-demented PD patients, 24 of whom had untreated early PD, and 18 healthy controls, were examined. Odor identification and discrimination data were corrected for odor detection scores. PD patients scored significantly lower on all olfactory tests. Interestingly, the subgroup of de novo patients with early PD also showed significant olfactory disturbances compared with healthy subjects. Within the PD group, using multiple regression analysis, we found a significant, negative correlation between odor discrimination measures and disease The present study is the first to describe decreased performance of PD patients on odor discrimination, in addition to the already well-established deficits in odor detection and identification. Furthermore, odor discrimination measures were related to disease severity, possibly indicating that at least some aspects of olfactory dysfunction in PD may be secondary to ongoing degenerative processes in PD. As significant olfactory impairments were found in early, de novo PD, olfactory tests may be useful in the early diagnosis of PD.
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PMID:Loss of olfaction in de novo and treated Parkinson's disease: possible implications for early diagnosis. 1121 91

Although the presence of an olfactory impairment in Parkinson's disease (PD) has been recognized for 25 years, its cause remains unclear. Here we suggest a contributing factor to this impairment, namely, that PD impairs active sniffing of odorants. We tested 10 men and 10 women with clinically typical PD, and 20 age- and gender-matched healthy controls, in four olfactory tasks: (i) the University of Pennsylvania smell identification test; (ii and iii) detection threshold tests for the odorants vanillin and propionic acid; and (iv) a two-alternative forced-choice detection paradigm during which sniff parameters (airflow peak rate, mean rate, volume, and duration) were recorded with a pneomatotachograph-coupled spirometer. An additional experiment tested the effect of intentionally increasing sniff vigor on olfactory performance in 20 additional patients. PD patients were significantly impaired in olfactory identification (P < 0.0001) and detection (P < 0.007). As predicted, PD patients were also significantly impaired at sniffing, demonstrating significantly reduced sniff airflow rate (P < 0.01) and volume (P < 0.002). Furthermore, a patient's ability to sniff predicted his or her performance on olfactory tasks, i.e., the more poorly patients sniffed, the worse their performance on olfaction tests (P < 0.009). Finally, increasing sniff vigor improved olfactory performance in those patients whose baseline performance had been poorest (P < 0.05). These findings implicate a sniffing impairment as a component of the olfactory impairment in PD and further depict sniffing as an important component of human olfaction.
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PMID:An impairment in sniffing contributes to the olfactory impairment in Parkinson's disease. 1125 73


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