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Biomedical subjects

G Mennuni

Publications and source records attributed to G Mennuni.

At least 19 recordsLinked to original sources
PubMed2005

Functional involvement of cerebral cortex in human narcolepsy.

The pathophysiology of human narcolepsy is still poorly understood. The hypoactivity of some neurotransmitter systems has been hypothesised on the basis of the canine model. To determine whether narcolepsy is associated with changes in excitability of the cerebral cortex, we assessed the excitability of the motor cortex with transcranial magnetic stimulation (TMS) in 13 patients with narcolepsy and in 12 control subjects. We used several TMS paradigms that can provide information on the excitability of the motor cortex. Resting and active motor thresholds were higher in narcoleptic patients than in controls and intracortical inhibition was more pronounced in narcoleptic patients. No changes in the other evaluated measures were detected. These results are consistent with an impaired balance between excitatory and inhibitory intracortical circuits in narcolepsy that leads to cortical hypoexcitability. We hypothesise that the deficiency of the excitatory hypocretin/orexin-neurotransmitter-system in narcolepsy is reflected in changes of cortical excitability since circuits originating in the lateral hypothalamus and in the basal forebrain project widely to the neocortex, including motor cortex. This abnormal excitability of cortical networks could be the physiological correlate of excessive daytime sleepiness and it could be the substrate for allowing dissociated states of wakefulness and sleep to emerge suddenly while patients are awake, which constitute the symptoms of narcolepsy.

Adult↗
PubMed2004

Does autonomic neuropathy play a role in erythropoietin regulation in non-proteinuric Type 2 diabetic patients?

AIMS: Erythropoietin (EPO)-deficient anaemia has been described in Type 1 diabetic patients with both severe autonomic neuropathy (AN) and proteinuria. This study was aimed at distinguishing between the effects of AN and nephropathy on haemoglobin and EPO levels in Type 2 diabetic patients at an early stage of diabetic nephropathy. METHODS: In 64 Type 2 diabetic patients (age 52 +/- 10 years, duration 10 +/- 9 years) without overt nephropathy and other causes of anaemia or EPO deficit, we assessed cardiovascular tests of AN, 24-h blood pressure (BP) monitoring, urinary albumin excretion rate (UAE), a full blood count, and serum EPO. RESULTS: Although the Type 2 diabetic patients with AN did not show differences in haemoglobin and EPO when compared with patients without AN, the presence of haemoglobin < 13 g/dl was associated with the presence of AN (chi(2)= 3.9, P < 0.05) and of postural hypotension (chi(2)= 7.8, P < 0.05). In a multiple regression analysis including as independent variables gender, body mass index, duration of diabetes, smoking, creatinine, 24-h UAE, 24-h diastolic BP, ferritin, erythrocyte sedimentation rate, and autonomic score, we found that the only variables independently related to haematocrit were autonomic score, ferritin and erythrocyte sedimentation rate. Finally, the physiological inverse relationship between EPO and haemoglobin present in a control group of 42 non-diabetic non-anaemic subjects was completely lost in Type 2 diabetic patients. The slopes of the regression lines between EPO and haemoglobin of the control subjects and the Type 2 diabetic patients were significantly different (t = 14.4, P < 0.0001). CONCLUSIONS: This study documents an early abnormality of EPO regulation in Type 2 diabetes before clinical nephropathy and points to a contributory role of AN in EPO dysregulation.

Adult↗
PubMed2002

[Fatigue and sleep: the point of view of the chronobiologist].

Chrono-fatigue is often present in patients engaged in shift or night work, as well as in passengers travelling across many time zones (jet lag syndrome). Some disturbances of the circadian system are responsible for clinical syndromes characterized by chrono-fatigue, one of them being the sleep delayed phase insomnia. Circadian sleep disorders, either functional or structural, are characterized not only by disturbances in sleep architecture and/or sleep quality, but also by the inability to fall asleep and stay awake at desired times. Similarly, sleep and fatigue present in those circadian disorders typically exhibit a daily cyclic pattern. Night workers and shift workers do have chronic sleep deprivation and desynchronisation of their circadian system with the entraining environment. Those phenomena are responsible for severe vigilance problems, a decrease in work productivity and deleterious health side effects. Fatigue and sleep problems in circadian disorders can now benefit from treatments based on the programed use of synchronizers of the circadian clock, like chronotherapy, bright light and melatonin, combined with adequate sleep hygiene recommendations.

Chronobiology Phenomena↗
PubMed1994

Autonomic neuropathy and transcutaneous oxymetry in diabetic lower extremities.

Transcutaneous oxygen tension is a useful method with which to assess the functional status of skin blood flow. The reduced values observed in diabetic patients have been interpreted as a consequence of peripheral vascular disease. However, diabetic patients show lower transcutaneous oxygen tension values than control subjects with equivalent degrees of peripheral vascular disease, suggesting that additional factors are involved. Since the autonomic nervous system influences peripheral circulation, we studied the relationship between autonomic neuropathy and foot transcutaneous oxymetry in non-insulin-dependent diabetic (NIDDM) patients without peripheral vascular disease. The following age-matched patients were selected and evaluated: control subjects, C, (n = 20), NIDDM patients without autonomic neuropathy, D, (n = 16) and with autonomic neuropathy, DN, (n = 20). All diabetic patients showed lower transcutaneous oxygen tension values than control subjects, while no differences were observed between the diabetic patients with and without autonomic neuropathy. In addition the saturation index that increases in the presence of autonomic neuropathy does not correlate with foot TcPO2. In conclusion autonomic neuropathy does not influence foot TcPO2 and therefore it is unlikely that it contributes to development of foot lesions during induction of foot skin ischaemia.

Autonomic Nervous System↗
PubMed1994

Autonomic neuropathy influences great toe blood pressure.

OBJECTIVE: To assess the influence of autonomic neuropathy on toe blood pressure (TBP), a parameter used currently as an ischemic index. RESEARCH DESIGN AND METHODS: The age-matched study subjects included 20 non-insulin-dependent diabetes mellitus (NIDDM) patients with autonomic neuropathy (DN) and 10 NIDDM patients without autonomic neuropathy (D), assessed by standard cardiovascular tests and galvanic skin response, and 8 control subjects (C). None of the subjects had peripheral vascular disease (PVD) (ankle/brachial index 0.9-1.1. RESULTS: The TBP and toe/brachial index (TBI) were significantly lower in DN than in C and D (P < 0.01). The saturation index (SI), the ratio between foot venous and arterial partial pressure of oxygen (PO2), was significantly higher in DN than in C and D (P < 0.05). An inverse relationship was found between TBI and SI (r = 0.554, P = 0.001). CONCLUSIONS: The autonomic nervous system directly influences peripheral circulation. In diabetic patients without PVD, a failure of sympathetic fibers caused by autonomic neuropathy could lead to a reduction of TBP. Therefore, TBP cannot be used as an ischemic index in diabetic patients.

Analysis of Variance↗
PubMed1990

Mineral waters in treatment of metabolic changes from fatigue in sportsmen.

The authors list the principal metabolic consequences of fatigue in athletes with special reference to alterations of fluid-electrolyte balance, acid-base balance, macroelements and trace elements. They then go on to stress the role which mineral waters, especially the bicarbonate ones, can play in the compensation of these disorders thus preventing or curing the fatigue syndrome in athletes.

Bicarbonates↗
PubMed1989

[Hydrological therapy of renal lithiasis].

The spa treatment most widely used in the management of renal calculosis is the drinking of a certain amount of mineral water under certain predetermined conditions of temperature, time and rhythm. These treatments are always indicated unless there are obstacles to the passage of urine or general contraindications. Chances for success are increased if the diagnosis is exact and the stone has been located. The results obtained by various authors are reported and their statistical validity is discussed. Favorable effects consist in: increased diuresis with urine dilution and correspondingly reduced concentration of lithogenic salts and hence supersaturation of urine; reduced concentration of microorganisms; changes in the physiological condition of the renal medulla; changes in inhibitors of crystallization, in urinary pH; mechanical effect on the urinary passages; increased ureter motility; expulsion of small stones and sand; preventive action on recurrences after surgery and after extra-corporeal shock-wave treatment, percutaneous therapy and uretero-nephroscopy.

Diuresis↗
PubMed1989

[Opioid peptides and digestive activity. Recent directions of physiopathology].

The authors, after having set out the classification and general significance of endogenous opioids (e.o.) on the basis of the most recent researches, have focused attention on the activity of the opioid peptides in gastroenterology. They summarize the main effects of the opioids on the basic digestive functions: secretion, endoluminal digestion, motility, absorption. Particular importance is attributed to the activity of the e.o. on gastric and duodenal secretion. Finally, the possible therapeutic implications of e.o. in the management of digestive disorders are examined.

Digestion↗
PubMed1983

[Myasthenia and sleep].

A Central Nervous System (CNS) acetylcholine receptors involvement in Myasthenia Gravis (MG) has been suggested but never fully demonstrated. On the other hand, although the question concerning the neurotransmitters connected to REM sleep is still unsettled, the importance of acetylcholine as a neurotransmitter involved in the maintenance of this sleep stage has been outlined. The spontaneous night sleep organization has been studied in 9 male subjects with MG and results are compared with those obtained in normal subjects matched for age and sex. Statistically significant differences have been found: 1) slow-waves sleep better represented in MG patients; 2) average REM period length shorter in MG patients; 3) instability of the EEG consisting in a tendency toward lightening of sleep. These findings may confirm the presence of a disturbance in the CNS cholinergic activity of MG patients.

Adult↗
PubMed1981

Sleep and human cerebellar pathology.

The organization and the quantitative evaluation of sleep stages were studied in patients with cerebellar syndrome. 25 polygraphic night recordings were scored according to the criteria suggested by Rechtschaffen & Kales (1968) and the sleep parameters investigated were referred to those indicated by Williams et al. (1974). The results matched with a homogeneous sample of normal subjects. Significant alterations were observed for several parameters of sleep, and the possible causes discussed.

Adolescent↗
PubMed1978

Night sleep organization in patients with severe hepatic failure. Its modifications after L-dopa treatment.

20 subjects with severe hepatic failure have been studied by means of all night polygraphic sleep recordings. Base night recordings have been made, as well as registrations after treatment with drugs that are known to improve the clinical conditions of these patients, especially concerning the psychic performances. Base night recordings show sleep disruption, with a large amount of wakefulness at the beginning of the registrations and during the night itself; sleep stages are strongly reduced, especially REM sleep. After L-dopa treatment, these negative patterns are furthermore enhanced and the percentage incidence of the REM stage is very low; nevertheless, this behaviour goes side by side with a light improvement in psychological performances. On the contrary, therapy with lactulose seems to improve the neuropsychiatric state and the sleep organization; as a matter of fact, wakefulness is lower in the night records after lactulose treatment, whilst the percentage incidence of sleep stages tends back toward normality; REM sleep has clearly risen.

Adult↗
PubMedDate not supplied

Distal muscular dystrophy with autosomal recessive inheritance.

Two sisters presented with distal weakness and their muscle biopsy was dystrophic. This distal muscular dystrophy has an autosomal recessive inheritance and its features are somewhat different from the more common autosomal dominant distal muscular dystrophy and include: a) onset in early adult life; b) involvement of distal leg muscles and especially peroneal muscles; c) marked early elevation of serum creatine kinase (CK); d) brief duration, small amplitude motor units and fibrillation on electromyography; and e) histologic features of a dystrophic myopathy.

Adolescent↗
PubMedDate not supplied

Sleep microstructure and EEG epileptiform activity in patients with juvenile myoclonic epilepsy.

Clinical and EEG manifestations of juvenile myoclonic epilepsy (JME) occur in a strict relationship to the sleep-wake cycle, particularly to transition phases (awakening, falling asleep, afternoon relaxation after work). JME manifestations are deactivated during sleep. Because arousal fluctuations during NREM sleep may be controlled by the same neurophysiologic mechanisms regulating awakening, we studied the relationship between the cyclic alternating pattern (CAP) and JME manifestations. All-night polysomnographic recordings of 10 JME patients were analyzed for variations of epileptiform EEG abnormalities in relation to sleep stages and to different microstructural variables (NCAP, CAP, phases A and B). CAP rates (ratio between total CAP duration and total NREM sleep duration) were also calculated. Average CAP rate was 46.70%, significantly higher than that (23%) of an age-matched control group. Macrostructural analysis showed only a trend toward a slight predominance of EEG epileptiform activity during slow wave sleep but no significant correlation between spiking rates and sleep stages. Microstructural analysis confirmed the CAP modulation of EEG epileptiform activity, with maximum appearance of epileptiform abnormalities during phase A CAP (normalized spiking rate = 4.00 +/- 0.98) and strong inhibition during phase B (0.06 +/- 00.6). Intermediate values were noted during NCAP (0.54 +/- 0.27). No correlation was noted between spiking rates during NREM sleep and CAP rates, possibly indicating that in JME patients the increased CAP rate may be partially independent of epileptiform EEG activity. Our data suggest that in JME patients CAP may be a neurophysiologic oscillator organizing expression of the epileptiform discharges independent of the tendency of the individual patient to produce epileptiform EEG discharges.

Activity Cycles↗