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)

Population aging is continuously increasing in Italy and in the World. Individuals aged 60 years or more are currently 10,500,000 and will be 13,000,000 in 2015. Life quality in geriatric ages includes the maintenance of sexual power: according to recent data (Carrol et al., 1992), 80% of impotence cases are due to organic causes. In addition, the use of drugs can cause impotence. Among them tiazidic diuretics may cause an increase of sexual disturbances. Other drugs with this potential are digitalis, antihypertensive drugs (particularly beta blockers), major and minor tranquillizers, antidepressant, H2 receptor antagonists, antiparkinsonian cholinergic drugs and estrogens employed in the treatment of prostate tumors. Diseases of geriatric age that can alter sexual power are diabetes mellitus, ischemic heart disease for the accompanying depression and for the use of antidepressants; severe hypertension is complicated by impotence in 15% of cases. Among neurological diseases Parkinson's disease and multiple sclerosis can be causes of sexual dysfunctions. Patients on hemodialysis can be impotent, with recent data (Soloh et al 1992) showing that erythropoietin treatment of anemia also improve sexual dysfunctions. Prevention from a geriatric standpoint should be base on action on known risk factor as smoking, alcohol abuse and dislipidemias and with the activation of a close drug vigilance.
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PMID:[Andrologic problems and internal pathology in the elderly]. 825 79

Four different forms of primary autonomic failure (multiple system atrophy, pure autonomic failure, Parkinson's disease and dopamine beta-hydroxylase deficiency) have been described. The first part of the article will focus on the interest to pharmacology of elucidating pathophysiological mechanisms underlying autonomic involvement at the central level (growth hormone response to clonidine acute challenge), presynaptic level (plasma catecholamine levels after yohimbine administration) and on post-synaptic receptors (binding studies, pressor responses to noradrenaline). The second part will discuss efficacy and side-effects of some of the many drugs which are currently proposed for the treatment of one of the most disabling symptoms related to autonomic failure, orthostatic hypotension. Special attention will be paid to drugs acting on blood composition (fludrocortisone, erythropoietin), on post-synaptic alpha-adrenoceptors (midodrine and clonidine) and on noradrenaline spill-over (yohimbine and L-Threo-DOPS).
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PMID:[Pharmacologic approach to autonomic failure]. 977 98

We have come to understand apoptosis as not merely a single form of cell death, but as a fundamental theme in cell biology that has far-reaching implications in the fields of physiology and pathology. At the present time, however, the mechanism of apoptosis is not clearly understood, as research into apoptosis is still at the initial stages. Nevertheless, the links between apoptosis and a variety of pathological conditions are gradually becoming clearer. In this article, we will provide a simple explanation of apoptosis and its mechanism as a novel concept of cell death and discuss the way in which apoptosis has been linked to a variety of pathological conditions. WHAT IS APOPTOSIS?: In normal tissue, cells that are no longer needed are rapidly eliminated without affecting the overall function of the tissue. In this process cells undergo an active and spontaneous suicide called programmed cell death. In fact, the majority of physiological cell deaths take the form of apoptosis. The word apoptosis is used, in contrast to necrosis, to describe the situation in which a cell actively pursues a course toward death upon receiving certain stimuli [1]. The morphological changes of apoptosis found in most cell types first involve contraction in cell volume and condensation of the nucleus. When this happens the intracellular organelles such as the mitochondria retain their normal morphology. As apoptosis proceeds, blebbing of the plasma membrane occurs, and the nucleus becomes fragmented. Finally, the cell itself fragments to form apoptotic bodies that are engulfed by nearby phagocytes. With respect to biochemical changes, it is known that the chromosomes become fragmented into nucleosome units, and DNA forms characteristic ladder patterns when subjected to agarose gel electrophoresis. MECHANISM OF APOPTOSIS: It has been reported that apoptosis is induced in various cells by many kinds of irritations, but the precise mechanism is still unclear. Cell injuries that induce apoptosis include those that cause DNA damage such as radiation and anticancer drugs, those that are mediated by the TNF receptor and Fas receptor (the so-called "death signal receptors"), and the deprivation of cytokines that supply survival signals such as IL-3 and erythropoietin. The tumor suppressor gene p53 plays a very important role in apoptosis induced by damage to DNA. This has been demonstrated by studying resistance to apoptosis of cells derived from p53 knockout mice [2]. Other than the irritations that induce apoptosis, molecules that have been strongly implicated as major players in the drama of apoptosis include the Bcl-2 family proteins and the IL-1 converting enzyme (ICE) and its homolog proteases (caspase family). Both groups of proteins show homology with proteins that affect cell death in nematodes. It is believed that molecules that contribute to cell death have been well conserved in multicellular organisms all the way from the relatively primitive nematodes to mammals including humans. It was discovered that Bcl-2 suppressed apoptosis induced in IL-3 dependent cells by deprivation of IL-3 [3]. It has since become the gene around which apoptosis research revolves. Recently, it has become clear that cell death involving the Bcl-2 protein is under the control of similar proteins from the same family [4]. It is interesting that the phenomenon of cell death may be regulated by the balance of the molecules involved in it. APOPTOSIS ABNORMALITIES AND DISEASE: Physiological cell death plays a major role in the growth and permanent maintenance of the human body [5]. In the process of forming the nervous system, neurons that do not form proper connections die. Physiological cell death also accompanies the removal of virus-infected cells by cytotoxic T cells, the elimination of autoreactive immune cells, the formation of the gut, the reconstitution of cartilage and bone, etc. When physiological cell death that normally should occur is inhibited, inappropriate physiological cell death may occur that is harmful to the body and forms the basis of disease. For example, in patients with neural degenerative disorders such as Alzheimer's disease and Parkinson's disease, we can find premature cell death in a particular subset of neurons. The death of T cells in AIDS patients is also a form of physiological cell death. Inhibition of cell death in the immune system enables the survival of autoreactive B cells and T cells, and is therefore a cause of autoimmune disorders. Apoptosis has been particularly linked to cancer. Normal cells are programmed for death if they are subjected to many types of non-physiological stress such as anticancer drugs or radiation, if they become isolated from surrounding cells and are unable to receive their tissue-specific survival signals [6], or if oncogenes are expressed haphazardly [7]. On the other hand, it is believed that the ability to survive is enhanced in transformed cancer cells because they are more resistant to apoptosis, they exhibit resistance to anticancer drugs, they are no longer dependent on survival signals, and they can metastasize. Therefore, the cancer progresses as the cancer cells maintain the proliferative superiority they acquire from their oncogenes. In other words, when cancer cells become resistant to apoptosis, they become resistant to treatment, metastasize, and proliferate destructively. The concept that the malignancy of cancer is due to its resistance to apoptosis is a relatively new one and is worthy of further study.
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PMID:Physician Education: Apoptosis. 1038 21

Serum erythropoietin (EPO) levels are partially controlled by the sympathetic outflow to the kidney. We have studied whether patients with multiple system atrophy (MSA), known to be associated with dysautonomia, are EPO-deficient. Eighteen MSA patients were studied along with 32 idiopathic Parkinson's disease (PD) patients, 23 controls with iron-deficiency anaemia, and 18 healthy individuals. Serum creatinine was normal in all groups. Mean haemoglobin (Hb) concentration in MSA patients was 13.7 +/- 1.7 g/dL. Four MSA patients had unexplained anaemia (minimum Hb: 10.5 g/dL) and abnormal autonomic function tests including significant postural hypotension, whereas none of the PD patients was anaemic. Serum EPO levels were suppressed in relation to anaemia in MSA patients compared to elevated EPO levels in iron-deficiency anaemia patients (difference of regression lines P < 0.001), indicating EPO deficiency in the anaemic MSA patients. Serum EPO levels in PD patients were within normal range. A subset of MSA patients has anaemia and postural hypotension, which may be associated with EPO deficiency. This may have therapeutic implications.
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PMID:Erythropoietin deficiency and anaemia in multiple system atrophy. 1129 75

Orthostatic hypotension is the most incapacitating symptom of autonomic failure. This disorder occurs with both central autonomic neurodegenerative disorders, such as multiple system atrophy and Parkinson's disease, and peripheral autonomic disorders, such as the autonomic peripheral neuropathies and pure autonomic failure. The hallmark of both central and peripheral causes of neurogenic orthostatic hypotension is the failure to release norepinephrine appropriately upon standing. Patient education is the cornerstone of management. There are several measures that can be implemented to improve orthostatic tolerance prior to pharmacological intervention. Plasma volume expansion is essential to improve orthostatic tolerance, and fluid and sodium chloride intake should be increased. Most patients can be treated successfully with volume expansion or fludrocortisone or both in combination with a sympathomimetic agent. Desmopressin acetate and erythropoietin are useful supplementary agents in patients with more refractory symptoms. There are rare patients who will require additional agents to treat their symptoms. A small group of patients remain refractory to all therapeutic modalities.
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PMID:Treatment of orthostatic hypotension. 1508 64

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the death of midbrain dopaminergic neurons. In the present study, erythropoietin, a trophic factor that has both hematopoietic and neural protective characteristics, was investigated for its capacity to protect dopaminergic neurons in experimental Parkinson's disease. Using both the dopaminergic cell line, MN9D, and primary dopamine neurons, we show that erythropoietin (1-3 U/mL) is neuroprotective against the dopaminergic neurotoxin, 6-hydroxydopamine. Protection was mediated by the erythropoietin receptor, as neutralizing anti-erythropoietin receptor antibody abrogated the protection. Activation of Akt/protein kinase B (PKB), via the phosphoinositide 3-kinase pathway, is a critical mechanism in erythropoietin-induced protection, while activation of extracellular signal-regulated kinase (ERK)1/2 contributes only moderately. Indeed, transfection of constitutively active Akt/PKB into dopaminergic cells was sufficient to protect against cell death. Furthermore, erythropoietin diminished markers of apoptosis in MN9D cells, including caspase 9 and caspase 3 activation and internucleosomal DNA fragmentation, suggesting that erythropoietin interferes with the apoptosis-execution process. When erythropoietin was administered to mice unilaterally lesioned with 6-hydroxydopamine, it prevented the loss of nigral dopaminergic neurons and maintained striatal catecholamine levels for at least 8 weeks. Erythropoietin-treated mice also had significantly reduced behavioral asymmetries. These studies suggest that erythropoietin can be an effective neuroprotective agent for dopaminergic neurons, and may be useful in reversing behavioral deficits associated with Parkinson's disease.
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PMID:Erythropoietin protects against 6-hydroxydopamine-induced dopaminergic cell death. 1633 25

Parkinson's disease (PD) is a neurodegenerative disease marked by severe loss of dopamine (DA) neurons in the nigrostriatal system, which results in depletion of striatal DA. Transplantation of embryonic ventral mesencephalic (VM) DA neurons into the striatum is a currently explored experimental treatment aimed at replacing lost DA in the nigrostriatal system, but is plagued with poor survival (5-20%) of implanted neurons. Here, we tested the ability of erythropoietin (Epo) to provide neuroprotection for embryonic day 14 (E14) VM DA neurons. Epo was tested in vitro for the ability to augment tyrosine hydroxylase-immunoreactive (TH-ir) neuron survival under normal cell culture conditions. In vitro, Epo did not increase the number of TH-ir neurons when administered at the time of plating the E14 VM cells in culture. We also tested the efficacy of Epo to enhance E14 VM transplants in vivo. Rats unilaterally lesioned with 6-hydroxydopamine received transplants that were incubated in Epo. Treatment with Epo produced significant increases in TH-ir neuron number, soma size, and staining intensity. Animals receiving Epo-treated grafts exhibited significantly accelerated functional improvements and significantly greater overall improvements from rotational asymmetry compared to control grafted rats. These data indicate that the survival of embryonic mesencephalic TH-ir neurons is increased when Epo is administered with grafted cells in a rodent model of PD. As direct neurotrophic effects of Epo were not observed in vitro, the mechanism of Epo neuroprotection remains to be elucidated.
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PMID:Exogenous erythropoietin provides neuroprotection of grafted dopamine neurons in a rodent model of Parkinson's disease. 1636 81

Low dopaminergic cell survival and suboptimal fiber reinnervation are likely major contributing factors for the limited benefits of neural transplantation in Parkinson's disease (PD) patients. Glial cell lined-derived neurotrophic factor (GDNF) has been shown to enhance dopaminergic cell survival and fiber outgrowth of the graft site as well as promote behavioral recovery in rodent models of PD, while erythropoietin (EPO) can produce dopaminergic neuroprotective effects against 6-hydroxydopamine (6-OHDA) exposure on cultured neurons and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice. The aim of this study was to determine if fetal ventral mesencephalic (FVM) tissue exposed to hibernation media containing a combination of GDNF and EPO could enhance dopaminergic graft survival, striatal reinnervation and functional recovery in a 6-OHDA rodent model of PD. FVM tissue was dissected from 14-day-old rat fetuses and placed for 6 days in hibernation media alone, and in hibernation media that received either a daily administration of GDNF, EPO or a combination of GDNF and EPO. Following hibernation, FVM cells were transplanted as a single cell suspension into the striatum of unilateral 6-OHDA-lesioned rats. Rotational behavioral assessment revealed animals that received FVM tissue exposed to GDNF, EPO or the combination of both drugs had accelerated functional recovery. Immunohistochemical and stereological assessment revealed a significant increase in graft fiber density and angiogenesis into the graft when compared with control. These findings suggest that the hibernation of FVM tissue in a combination of GDNF and EPO can enhance graft efficacy and may have important implications for tissue preparation protocols for clinical neural transplantation in PD.
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PMID:Erythropoietin and GDNF enhance ventral mesencephalic fiber outgrowth and capillary proliferation following neural transplantation in a rodent model of Parkinson's disease. 1690 47

To investigate the neuroprotective effects of erythropoietin (EPO) in a rodent model of Parkinson disease, we inoculated a nonreplicating herpes simplex virus-based vector expressing EPO (vector DHEPO) into the striatum of mice 1 week prior to, or 2 weeks after, the start of continual administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (4 mg/kg intraperitoneally, 5 of 7 days) for 6 weeks. Inoculation with DHEPO prior to MPTP intoxication preserved behavioral function measured by pellet retrieval and the histological markers of tyrosine hydroxylase-immunoreactive (TH-IR) neuronal cell bodies in the substantia nigra (SN) and TH-IR and dopamine transporter-immunoreactive (DAT-IR) terminals in striatum. Inoculation of DHEPO 2 weeks into a 6-week course of MPTP resulted in improvement of behavioral function and restoration of TH-IR cells in SN and TH- and DAT-IR in the striatum. The effects of vector-produced EPO were similar in magnitude to the effects of vector-mediated expression of glial-derived neurotrophic factor in the same model. These results demonstrate that vector-mediated EPO production may be used to reverse dopaminergic neurodegeneration in the face of continued toxic insult.
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PMID:HSV-mediated delivery of erythropoietin restores dopaminergic function in MPTP-treated mice. 1694 43

The neuroprotective effects of erythropoietin on 1-methyl-4-phenylpyridinium (MPP(+))-induced oxidative stress and apoptosis in cultured PC12 cells as well as the underlying mechanism were investigated. Treatment of PC12 cells with MPP(+) caused the loss of cell viability, which was associated with the elevation in apoptotic rate, the formation of reactive oxygen species and the disruption of mitochondrial transmembrane potential. It was also shown that MPP(+) significantly induced upregulation of Bax/Bcl-2 ratio and activation of caspase-3. In contrast, erythropoietin reversed these phenotypes and had its maximum protective effect at 1 U/ml. The effect of erythropoietin was mediated by the phosphatidylinositol 3-kinase (PI3K) signaling pathway since erythropoietin failed to rescue cells from MPP(+) insult in the presence of the PI3K inhibitor, LY 294002. In addition, the downstream effector of PI3K, Akt, was activated by erythropoietin, and Akt activation was inhibited by LY 294002. Furthermore, the effect of erythropoietin on reactive oxygen species levels was also blocked by LY 294002. These results show that erythropoietin may provide a useful therapeutic strategy for the treatment of oxidative stress-induced neurodegenerative diseases such as Parkinson disease.
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PMID:Antioxidant effect of erythropoietin on 1-methyl-4-phenylpyridinium-induced neurotoxicity in PC12 cells. 1736 20


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