Biomedical subjects

Mona Pache

Publications and source records attributed to Mona Pache.

22 records · Page 2Linked to original sources

PubMed2002

Distribution of melatonin MT1 receptor immunoreactivity in human retina.

Melatonin is synthesized in the pineal gland and retina during the night. Retinal melatonin is believed to be involved in local cellular modulation and in regulation of light-induced entrainment of circadian rhythms. The present study provides the first immunohistochemical evidence for the localization of melatonin 1a-receptor (MT1) in human retina of aged subjects. Ganglion, amacrine, and photoreceptor cells expressed MT1. In addition, MT1 immunoreactivity was localized to cell processes in the inner plexiform layer and to central vessels of the retina, as well as to retinal vessels but not to ciliary or choroidal vessels. These results support a variety of cellular and vascular effects of melatonin in the human retina. Preliminary evidence from patients with Alzheimer's disease (AD) revealed increased MT1 immunoreactivity in ganglion and amacrine cells, as well as in vessels. In AD cases photoreceptor cells were degenerated and showed low MT1 expression.

Age Factors↗

PubMed2002

Elevated plasma endothelin-1 levels and vascular dysregulation in patients with rheumatoid arthritis.

BACKGROUND: Contradictory results on plasma endothelin-1 (ET-1) levels in patients with rheumatoid arthritis have been reported in previous studies. We therefore evaluated whether plasma ET-1 levels in patients with rheumatoid arthritis differ from those of normal controls. Since systemically increased levels of ET-1 are known to occur in tandem with primary or secondary vascular dysregulation, we also measured peripheral blood flow by means of nailfold capillaroscopy combined with a cold provocation test. MATERIAL/METHODS: We measured plasma levels of ET-1 in twelve patients with different stages of rheumatoid arthritis by means of a specific radioimmunoassay, and compared ET-1 values to those of healthy controls. Capillary blood flow and the frequency of cold-induced vasospasm were studied in parallel, using nailfold capillaroscopy combined with a cold provocation test. RESULTS: Plasma ET-1 levels were significantly increased in patients with rheumatoid arthritis (p = 0.01) when compared to controls (2.38+/-0.95 pg/ml vs. 1.53+/-0.38 pg/ml). Capillary blood flow was reduced when compared to our own normal values, and a cold-induced blood standstill was seen in 58% of the patients. CONCLUSIONS: Patients with rheumatoid arthritis exhibit significantly elevated levels of ET-1, which may be associated with the symptoms of vascular dysregulation observed in nailfold capillaroscopy. Even though the clinical conclusions should be drawn from this study with caution, additional therapy with calcium channel blockers or, possibly in the future, with ET-1 receptor blockers, may be beneficial in patients with rheumatoid arthritis.

Adult↗

PubMedDate not supplied

A sick eye in a sick body? Systemic findings in patients with primary open-angle glaucoma.

Despite intense research, the pathogenesis of primary open-angle glaucoma (POAG) is still not completely understood. There is ample evidence for a pathophysiological role of elevated intraocular pressure; however, several systemic factors may influence onset and progression of the disease. Systemic peculiarities found in POAG include alterations of the cardiovascular system, autonomic nervous system, immune system, as well as endocrinological, psychological, and sleep disturbances. An association between POAG and other neurodegenerative diseases, such as Alzheimer disease and Parkinson disease, has also been described. Furthermore, the diagnosis of glaucoma can affect the patient's quality of life. By highlighting the systemic alterations found in POAG, this review attempts to bring glaucoma into a broader medical context.

Cardiovascular Diseases↗

PubMedDate not supplied

Dawn-dusk simulation light therapy of disturbed circadian rest-activity cycles in demented elderly.

We investigated whether low intensity dawn-dusk simulation (DDS), a 'naturalistic' form of light therapy designed to embed sleep in its accustomed phase, could improve the disturbed circadian rest-activity cycle, nocturnal sleep and and/or cognitive functions in dementia. A protocol of 3 weeks each of baseline, treatment and follow-up was completed by 13 patients (85yr old+/-5yr, MMSE 14+/-5; n=9 DDS versus n=4 'placebo' dim red light) who wore an activity/lux monitor throughout. There were no significant changes in clinical or cognitive status, nor modification of circadian stability or amplitude characteristics of the rest-activity cycle. However, two aspects of sleep responded to DDS but not to dim red light. The main sleep episode was 1:14h earlier during treatment (p=0.03) compared with before and after DDS. With respect to actimetry-determined sleep variables, the DDS group tended to have shortened 'sleep latency', longer 'sleep duration', more nocturnal immobility and less nocturnal activity than the dim red group (p<0.1). In parallel, nighttime light exposure tended to be reduced (p=0.07). These promising findings-after only 3 weeks of light treatment in elderly patients with advanced dementia-suggest that the circadian timing system remains functionally responsive even to low intensity DDS light. Increasing zeitgeber strength is an important strategy for improving sleep quality and timing in dementia, and DDS light therapy may provide one of the appropriate means to do so.

Aged↗