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Biomedical subjects

S Smirne

Publications and source records attributed to S Smirne.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Neuroprotective effects of felbamate on global ischaemia in Mongolian gerbils.

Felbamate is an antiepileptic drug whose action appears to occur mainly through an interaction with neurotransmission mediated by excitatory amino acids. We assessed its effectiveness in a model of transient global ischaemia in Mongolian gerbils. Dizocilpine (MK 801) was used for comparison. Treatment was given 10 min after transient forebrain ischaemia which was performed by occluding both common carotid arteries for 10 min. Felbamate (300 mg/kg i.p.) increased the number of surviving neurons in the CA1, CA2 and CA3 hippocampal cells. In particular, the CA1 area had a significantly higher number of surviving pyramidal neurons than that of vehicle-treated animals (67 +/- 11 vs 33 +/- 6 surviving neurons/mm; P < 0.05). No significant difference in density of surviving neurons was observed between dizocilpine (3 mg/kg i.p.) and vehicle (54 +/- 10 vs 33 +/- 6 surviving neurons/mm). The EEG results indicated that the effect of felbamate, used alone, is the same in the ischaemic-vehicle group as non-ischaemic group. Our results show that felbamate exerts neuroprotective effects in a model of severe cerebral ischaemia.

Animals↗
PubMedDate not supplied

Cardiac autonomic function during sleep of never-depressed borderline subjects: a pilot study.

In a controlled 48 h ambulatory polysomnographic study of never-depressed subjects with DSM-III-R borderline (BDL) personality disorder (PD) we obtained measures of tonic and phasic heart rate variability. Subjects with BDL PD showed a significantly smaller index of tonic heart rate decrease during NREM sleep than normal controls. This is unlikely to be a state-dependent finding and it may derive from relative augmentation of adrenergic function compared to cholinergic function between wakefulness and NREM sleep. Hyperadrenergic states in BDL PD have already been suggested by studies of other biological indicators: a smaller index of tonic heart rate decrease may be a further correlate of core psychobiological dimensions such as impulsivity and affective instability.

Adrenergic Fibers↗
PubMedDate not supplied

Focal cerebral lesions found by magnetic resonance imaging in cryptogenic nonrefractory temporal lobe epilepsy patients.

Brain magnetic resonance imaging (MRI) was studied in patients with mild-to-moderate temporal lobe epilepsy (TLE), well controlled by pharmacotherapy, and with normal computed tomographic (CT) scans. Magnetic resonance imaging abnormalities were found in 19 patients; of these, nine had abnormalities in temporomesial regions and four in temporobasal regions. Six patients had white matter MRI lesions of nonspecific significance. The temporomesial MRI lesions were compatible with sclerosis of Ammonis cornu. Patients with this MRI finding had more severe and longer lasting TLE than those without MRI abnormalities. The temporobasal lesions were interpreted as potentially developing brain lesions. Correlation between EEG and MRI findings was good. We conclude that MRI is more useful than CT for diagnosis of patients with mild-to-moderate TLE.

Adult↗
PubMedDate not supplied

Growth hormone secretion in Alzheimer's disease: studies with growth hormone-releasing hormone alone and combined with pyridostigmine or arginine.

There is evidence that GH secretion is reduced in normal elderly subjects as well as in patients with Alzheimer's disease (AD). To clarify the mechanisms underlying this GH hyposecretory state in 14 elderly subjects (age 65-75 years) and 15 AD patients (age 61-78 years), we studied the effects of both pyridostigmine (PD, 120 mg orally), a cholinesterase inhibitor, and arginine (ARG, 0.5 g/kg i.v.), two substances likely acting via inhibition of hypothalamic somatostatin, on GH response to GHRH (1 microgram/kg i.v.). The GH response to PD alone was also studied. Twenty-two young healthy volunteers were studied as control group. Basal GH levels were similar in young, elderly and AD subjects (0.7 +/- 0.2, 0.8 +/- 0.2 and 0.9 +/- 0.2 microgram/l). IGF-I levels were lower (p < 0.005) in elderly (73.9 +/- 8.2 microgram/l) and in AD subjects (108.0 +/- 5.9 micrograms/l) than in young subjects (288.7 +/- 22.1 micrograms/l); however, they were higher (p < 0.01) in AD patients than in the elderly subjects. The PD-induced GH release did not significantly differ in young, elderly and AD subjects while the GH responses to GHRH in the elderly (AUC: 297.9 +/- 49.2 micrograms/l) and in AD subjects (437.6 +/- 93.5 micrograms/l/h) were lower (p < 0.01) than in young subjects (658.6 +/- 100.1 micrograms/l/h). PD potentiated the GH response to GHRH both in elderly and in AD subjects (901.7 +/- 222.4 and 1,070.3 +/- 207.2 micrograms/l/h, p < 0.005) but these responses were lower (p < 0.0001) than those recorded in young subjects (2,041.1 +/- 245.6 micrograms/l/h).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Cognitive processes in hypertension.

In 15 normotensive subjects, 17 newly diagnosed, untreated hypertensive patients, and 22 effectively treated hypertensive patients, a battery of neuropsychological tests was given. All subjects were neurologically asymptomatic. The neuropsychological battery included tests evaluating global cognitive functions (Card Sorting Test, Wechsler Memory Scale, Progressive Matrices 1938), as well as specific cognitive functions (Benton Test, subtests of the Wechsler-Bellevue Scale). Normotensive controls obtained better scores in all the tests. Statistical analysis of th scores suggests that hypertension is highly correlated with impairment of memory, logical reasoning, visuospatial organization, and attention. Therapy seems to impair attention, while the duration of disease seems to influence visuospatial performances.

Adult↗
PubMedDate not supplied

Homovanillic acid and 5-hydroxyindoleacetic acid modifications in CSF of patients with stroke and multi-infarct dementia.

Thirty four patients who had complete ischemic stroke confirmed by neurologic examination, were divided into three groups according to the time elapsed between the first signs of stroke and lumbar puncture: group A, 22-47 h; group B, 48-71 h; group C, 72-96 h. Nineteen patients with multi-infarct dementia (MID) assessed by neurologic and neurophysiologic examinations were also studied. The severity of the neurological deficit was assessed by the Norris rating scale. Nine age-matched subjects without neurologic disease served as controls. Levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were determined in lumbar CSF by a fluorimetric method after separation on Sephadex G-10 columns. HVA levels decreased as the length of time after stroke increased and were lower than controls in MID, while 5-HIAA levels were low in group B and MID. Our results in stroke can be interpreted as showing they are the consequence of dopamine and serotonin global depletion in the early phases of brain ischemia. In MID, the CSF changes might reflect not only tissue loss secondary to multiple infarcts but also the persistence of a state of diffuse ischemia.

Aged↗
PubMedDate not supplied

Peripheral motor-sensory neuropathy in membranous lipodystrophy (Nasu's disease): a case report.

A case of membranous lipodystrophy (ML) with peripheral polyneuropathy (PN) is described. A 40-year-old woman presented with dementia, multiple lytic bone lesions with typical membranous material in adipose tissues and neurophysiological and pathological findings of peripheral neuropathy. We describe the first case of ML with PN. It is interesting since nerve involvement might be an additional cause of symptoms usually attributed to bone lesions.

Adipose Tissue↗
PubMedDate not supplied

Age-related modifications of heart rate during sleep-wakefulness cycle.

Twenty-four-hour monitoring of heart rate is currently used in cardiological practice, but it has been rarely applied to investigate the autonomic nervous system functioning. In the present study we investigated the heart rate of 275 healthy subjects, aged 15-69 years, divided into 11 groups by 5-year periods of age. Our results suggest that the balance between parasympathetic and sympathetic activities changes with advancing age. The parasympathetic activity becomes stronger and during sleep loses its power to modulate bradycardia. The general conclusion of our study is that all the investigations on cardiac autonomic functions are to be performed on age-matched basis.

Adolescent↗