Biomedical subjects

R Casale

Publications and source records attributed to R Casale.

At least 19 recordsLinked to original sources

PubMed2004

Surface EMG alterations induced by underwater recording.

BACKGROUND AND PURPOSE: This study aims to verify if amplitude and spectral characteristics of surface EMG signal are modified due to recording in a wet environment. METHODS: Isometric contractions of the biceps brachii muscle of ten subjects were performed in several different set-up combinations, both in dry (D) and in water from hydrotherapy pools (PW), with (PWM) or without moving the pool water and with (T) or without water-resistant adhesive taping. RESULTS: In PW condition the amplitude of the recorded signal is reduced to 5-10% of the corresponding signal recorded in D condition. In PWM the power spectrum is drastically reduced and altered by the water movement that introduces an increase of spectral power in the frequency range 0-20 Hz. The use of T modality allows to record signals with both amplitude and spectral frequencies comparable with those obtained in the D conditions. DISCUSSION AND CONCLUSION: This work demonstrates the need for water resistant taping when EMG signals are recorded in water. Signals recorded without such a protective film are strongly affected in their amplitude and frequency characteristics by the conductivity and the movement of water.

Adult↗

PubMed2001

Nerve growth factor and neuropeptides circulating levels in systemic sclerosis (scleroderma).

OBJECTIVE: To determine the circulating levels of nerve growth factor (NGF), neuropeptide Y (NPY), and vasoactive intestinal peptide (VIP) in systemic sclerosis (SSc), and to correlate these levels with clinical and laboratory features. METHODS: Forty four patients with SSc were evaluated for circulating NGF (immunoenzymatic assay), NPY and VIP (radioimmunoassay), anticentromere and antitopoisomerase I autoantibodies, lung disease (pulmonary function tests with carbon monoxide transfer factor (TLCO), ventilation scintiscan with 99mTc DTPA radioaerosol, high resolution computed tomography (HRCT), pulmonary pressure (echo colour Doppler)), heart disease (standard and 24 ECG, echocardiography), cutaneous involvement (skin score), joint involvement (evidence of tender or swollen joints, or both), peripheral nervous system (PNS) involvement (electromyography), rheumatoid factor, angiotensin converting enzyme (fluorimetric method), von Willebrand factor (ELISA), and erythrocyte sedimentation rate (ESR) (Westergren). RESULTS: Circulating NGF levels in SSc were significantly increased compared with controls (p<0.00001) and significantly higher in the diffuse than in the limited subset of patients (p<0.01). Patients with articular disease had significantly higher levels of NGF. A significant indirect correlation between NGF levels and TLCO was detected (p<0.01), but no correlation was found between NGF and HRCT, DTPA, skin score, PNS involvement and angiotensin converting enzyme and von Willebrand factor levels, antitopoisomerase or anticentromere antibodies, and ESR. NGF levels increased progressively as the disease worsened. Similarly, VIP circulating levels were significantly increased in patients with SSc (p<0.001), whereas the increase of NPY levels did not reach statistical significance. However, both neuropeptides, following the same trend as NGF, increased as the disease worsened (skin score and lung disease). CONCLUSIONS: The increase of NGF and VIP in patients with SSc, the former in the diffuse subset of the disease, and in patients with prominent articular disease, may suggest a link between neurotransmitters and the disease pathogenesis. Neuropeptide circulating levels seem to increase only in patients with the most severe disease.

Biomarkers↗

PubMed2000

Erectile dysfunction in men with obstructive sleep apnea: an early sign of nerve involvement.

Erectile dysfunction (ED) is common in men with obstructive sleep apnea (OSAS) but no completely convincing hypotheses about the underlying pathogenic mechanisms have been published in the literature. The aims of the present study were to assess the presence of ED in a group of OSAS patients without daytime respiratory failure and to determine whether this dysfunction was related to peripheral nerve involvement. Evaluation of the bulbocavernosus reflex (BCR) and the somato-sensory evoked potentials of pudendal nerve (PSEPs), the most widely established method of documenting pudendal neuropathies as being the cause of impotence, was performed in 25 patients. Data on BCR were compared with those of 25 healthy males volunteers matched for age. BCR was altered in 17 patients: in 6 it was elicited while in 11 it had a prolonged latency and reduced amplitude. Patients with altered BCR presented an higher AHI, an higher percentage of sleep time spent with SaO2 <90% (TST90) and a lower daytime PaO2. Six patient had clinically silent neurophysiological signs of mild polyneuropathy. The degree of OSAS and gas exchange alteration was more severe in patients with polyneuropathy than in those with isolated BCR alteration. ED is a common finding in OSAS patients and this alteration seems to be related to a nerve dysfunction. The development of nerve dysfunction is associated with a more severe degree of OSAS and nocturnal hypoxia.

Arousal↗

PubMed2000

Absent innervation of skin and sweat glands in congenital insensitivity to pain with anhidrosis.

OBJECTIVES: A case of a 10-year-old girl with congenital insensitivity to pain with anhidrosis (CIPA) is reported. METHODS AND RESULTS: Parents referred several hyperpyretic episodes without sweating occurring since birth, and insensitivity to pain, noticed when the child was 2 years old. Her body had many bruises and scars, bone fractures and signs of self-mutilation. Neurological examination was normal except for insensitivity to pain. Her IQ was 52. Electrical and tactile sensory nerve conduction velocities were normal. The patient was unable to detect thermal stimuli. Histamine injection evoked a wheal but not a flare; pilocarpine by iontophoresis did not induce sweat. Microneurography showed neural activity from A-beta sensory fibers while nociceptive and skin sympathetic C fiber nerve activity was absent. No small myelinated fibers and very rare unmyelinated fibers were found in the sural nerve. Immunohistochemistry showed a lack of nerve fibers in the epidermis and only few hypotrophic and uninnervated sweat glands in the dermis. CONCLUSIONS: The lack of innervation of the skin (C and A-delta fibers) appears to be the morphological basis of insensitivity to pain and anhidrosis, and is consistent with the loss of unmyelinated and small myelinated fibers in the sural nerve biopsy.

Child↗

PubMed1999

Two methods for the measurement of voluntary contraction torque in the biceps brachii muscle.

Appropriate measurement of maximal voluntary contraction force of a single limb muscle or of a muscle group is important in clinical and research situations. To measure muscle force, one segment of an isometric measuring brace is fixed to a support and force is applied to the other. The output of this arrangement is affected by additional contributions such as pushing or pulling with the whole body. This paper quantifies the differences between measurements of torque produced by the biceps brachii with the brace fixed versus those produced when the elbow joint was isolated by suspending the brace from cables. No statistically significant differences were found between MVC values observed with the two methods within subjects. However, a statistically significant difference in EMG fatigue indices was observed and attributed to a different sharing of force production among different muscles in the two conditions. We conclude that different brace arrangements may lead to the same maximal force but to different rates of myoelectric manifestations of muscle fatigue since the effort may be shared differently among the muscles of synergic or stabilizing groups.

Adult↗

PubMed1998

Early development of EMG localized muscle fatigue in hand muscles of patients with chronic heart failure.

BACKGROUND: Patients with chronic heart failure (CHF) frequently complain of fatigue and exercise intolerance that are not directly related to the severity of cardiac failure. A not well-defined muscle function impairment is generally considered the cause of such symptoms. The frequency compression of electromyographic (EMG) signal power spectrum during isometric contractions is commonly accepted as an index of the fatigue occurring in the muscle (localized muscle fatigue). PURPOSE AND METHODS: The purpose of the study was to evaluate muscle fatigue development in a selected group of CHF patients by studying the compression of the EMG signal power spectrum. The first dorsal interosseus of the right, dominant hand was investigated at two levels of contraction: 40% and 80% of the maximal voluntary contraction (MVC). RESULTS: In CHF patients there was early development of localized muscle fatigue during the high level of contraction (80% of MVC). CONCLUSION: This study demonstrates the presence of an early development of localized muscle fatigue in CHF patients and confirms the possibility of an increased glycolytic metabolism. Moreover, the changes seem to show that muscle impairment is not limited to large muscles, but also occurs in small muscles of the hands, frequently used during daily activities. Finally, this study confirms the validity of EMG spectral analysis techniques in evaluating muscle fatigue of CHF patients, suggesting a possible use in the rehabilitation of such patients when the technique is correctly used.

Adult↗

PubMed1998

Circadian rhythm of arginine vasopressin in hepatorenal syndrome.

The etiology of hepatorenal syndrome is still incompletely understood, but the nonosmotic release of arginine vasopressin (AVP) seems to have an important role. Since AVP presents a well-defined daily periodicity in its production and secretion, the aim of the study was to investigate the circadian rhythm in its circulating plasma concentrations in patients with hepatorenal syndrome, compared with healthy controls. Venous blood samples were drawn during a 24 hour period at 2 hourly intervals from a peripheral vein in 10 healthy subjects and in 10 patients with hepatorenal syndrome for the determination of the circulating plasma levels of AVP by radioimmunoassay. Statistical analysis was carried out by the 'cosinor' method. The controls presented a significant (p < 0.002) circadian rhythm in the AVP circulating levels, whereas no rhythm (p > 0.05) was found in patients. The circadian rhythms were significantly (p < 0.005) different between the two groups, patients having higher mean daily concentration and lower circadian variation of AVP. These results confirm the existence of a well-defined circadian rhythm of AVP in healthy subjects, whereas the hepatorenal syndrome patients present a complete loss of the circadian rhythm. It could be hypothesized that primitive damage in circadian time-keeping regulates the circadian rhythm of vasopressinergic neurons, or has a secondary effect on the peripheral vasodilatation in the course of advanced liver disease. This great upset in the temporal and functional organization, together with that of the renin-angiotensin-aldosterone system, could play an important role in promoting and/or in the maintenance of the hydroelectrolyte imbalance that characterizes the hepatorenal syndrome.

Arginine Vasopressin↗

PubMed1998

Plasma levels of arginine vasopressin in hepatorenal syndrome.

BACKGROUND: The etiology of hepatorenal syndrome is still incompletely understood, but the non-osmotic release of arginine vasopressin (AVP) seems to have an important role in its pathogenesis. The aim of the study was to investigate the circulating plasma concentrations of AVP in patients with hepatorenal syndrome, compared with healthy controls, in relation with plasma osmolality. METHODS: Venous blood samples were drawn in 20 healthy subjects and in 20 patients with HRS for the determination of the plasma levels of AVP by radio-immunoassay and of plasma osmolality. The comparison between the two groups was carried out by the Student "t"-test for unpaired data; the plasma AVP levels were correlated with the values of plasma osmolality by linear regression analysis. RESULTS: The patients presented significantly (p < 0.001) higher plasma AVP levels in respect to controls; on the contrary, plasma osmolality was significantly lower in patients than in controls (p < 0.005). Whereas a significant (r = 0.83; p < 0.001) relationship was demonstrated between plasma AVP and osmolality in controls, no significant (r = 0.23; p > 0.05) correlation was found in patients. CONCLUSIONS: These results confirm the existence of an activation in the release of AVP in hepatorenal syndrome, due to the activation of the sympathetic adrenal system and to hyponatriemia. The contraction of diuresis in hepatorenal syndrome, on the other hand, is not due to a deficiency in plasma AVP. AVP release occurs despite low plasma osmolality, which normally inhibits its secretion. This great upset in functional organization, together with that of the atriopeptin-renin-angiotensin-aldosterone system, could play an important role in promoting and/or in the maintenance of the hydro-electrolyte imbalance that characterizes the syndrome.

Aged↗

PubMed1997

Systemic sclerosis (scleroderma): an integrated challenge in rehabilitation.

Systemic sclerosis (SSc), a multisystem disease involving the microvascular system and the connective tissue, is considered one of the most difficult rheumatic diseases to treat. The natural history of the disease evolves from an edematous to a scleroatrophic phase following two different temporal patterns: acute or chronic. The former leads to early death, and the latter evolves slowly toward severe disability that deserves rehabilitative intervention. Despite the poor prognosis, recent improvements in diagnosis and treatment have led to longer patient survival, thus increasing the need to intervene against the development of tissue fibrosis and contractures by using appropriate integrated rehabilitation programs. This article does not review the medico-pharmacological management of visceral manifestations of the disease. Rather, it is divided into six parts, which include analyses of the changes in skin, joints and tendons, and muscle induced by SSc; examination of the existing literature on rehabilitation strategies and treatments; discussions of the pain and peripheral sensory-motor system involvement that are present to a greater or lesser extent in almost all patients and influence not only the duration and outcome of rehabilitation but also the patient's family, social life, and working ability; and consideration of ergonomic and occupational interventions. No controlled studies have been done on the few rehabilitation guidelines and specific protocols identified, so it must be emphasized that this article is a summary of opinions expressed in the literature and the authors' own findings. Particularly lacking are studies on such aspects as ergonomics, work intervention, or the management of sexual dysfunction. Experience gained in the rehabilitation of skin burns and other rheumatic diseases forms the basis for a logical approach to SSc patients.

Acute Disease↗

PubMed1997

Circadian rhythms of plasma atriopeptin, plasma renin activity and plasma aldosterone in patients with hepatorenal syndrome.

The etiology of hepatorenal syndrome (HRS) is still incompletely understood, but the atriopeptin-renin-aldosterone system plays an important role in its pathogenesis. Since this system presents a circadian rhythmicity, the aim of the study was to investigate the circadian rhythm in the circulating concentrations of atriopeptin (atrial natriuretic peptide, pANP), plasma renin activity (PRA) and plasma aldosterone (pA) in patients with HRS, compared with healthy controls. Venous blood samples were drawn during the span of a whole day and every two hours from a peripheral vein in 10 healthy subjects and in 10 patients with HRS. The circulating concentrations of pANP, PRA and pA were determined by radioimmunoassay. Statistical analysis was carried out by the "cosinor" method. The controls presented a significant (p < 0.05) circadian rhythm for each variable, whereas no rhythm (p > 0.05) was found in HRS patients. The pANP, PRA and pA rhythms were significantly (p < 0.05) different between the two groups, HRS patients having higher mean daily concentrations and larger circadian variations of pANP, PRA and pA than controls. Significant relations (p < 0.05) were demonstrated between the mean daily concentrations of pANP and PRA (r = 0.79), PRA and pA (r = 0.73) and PRA and pA (r = 0.76) in the controls; on the contrary, the HRS patients showed only a significant (p < 0.05) positive relation between pANP and PRA (r = 0.71). These results confirm the previous observation that the atriopeptin-renin- aldosterone system presents a well-defined circadian time structure in healthy subjects, while the HRS patients present a complete loss of the secretory sequentiality and of the circadian rhythm, with desynchronization of the whole system. This great upset in the temporal and functional organizations of the system could play an important role in promoting and/or in maintaining the hydro-electrolyte unbalance of HRS.

Aldosterone↗

PubMed1997

Monoclonal gammopathy of undetermined significance evolving directly in primary plasma cell leukemia.

A case of monoclonal gammopathy of undetermined significance (MGUS) which evolved directly into primary plasma cell leukemia (PCL) is reported. Even if MGUS and PCL represent the opposite aspects of the same immunoproliferative disorder, no previous cases of this direct evolution have been described, as stated by an accurate review of the specific literature. The patient abruptly developed PCL after five months from the discovery of a serum monoclonal spike, without any other clinical, laboratory and radiological abnormalities. The practical conclusions of this case report indicate that a patient with MGUS must be followed periodically and over an indefinite period, and that PCL must be considered into the possible evolution of MGUS.

Humans↗

PubMed1997

Risk of malignant transformation in patients with monoclonal gammopathy of undetermined significance.

The acturial probability of malignant transformation was analyzed in a series of 263 patients with monoclonal gammopathy of undetermined significance (MGUS) over a 15-year period and followed from 5 to 20 years. At a median follow-up of 11.5 years, 157 patients (59.7%) had died of causes unrelated to MGUS, 47 (17.9%) were still alive and presented no increase in monoclonal component, 11 (4.1%) presented an increase in monoclonal component without evidence of malignant immunoproliferative disease, and 48 (18.3%) had developed a malignant transformation of MGUS. In particular, MGUS evolved into 35 cases of multiple myeloma, two of solitary plasmacytoma of the bone, four of macroglobulinemia, three of malignant lymphoma, two of amyloidosis, one of chronic lymphocytic leukemia, and one of plasma cell leukemia. The cumulative incidence of malignant transformation was 18.3%; and the actuarial risk of malignant transformation was 6.1, 15.4, and 31.3% at 5, 10 and 20 years, respectively. The multivariate regression analysis according to Cox's proportional hazard model selected among 22 different variables established at initial diagnosis of MGUS only age as the factor significantly (P < 0.011) and negatively (b = -1.104) related to the risk of developing a malignant immunoproliferative disease. Therefore, patients with MGUS present an increased risk of developing a malignant lymphoproliferative or plasma cell proliferative disease, and MGUS could be considered a pre-neoplastic condition. Since no clinical or laboratory features are able to identify in advance the patients at high risk of disease progression, each patient must be followed up periodically and over an indefinite period.

Actuarial Analysis↗

PubMed1997

Rapid fall in sympathetic nerve hyperactivity in patients with heart failure after cardiac transplantation.

BACKGROUND: Severe heart failure is associated with an intense sympathetic nerve hyperactivity. After cardiac transplantation, neurochemical studies have indicated a normalization of sympathetic outflow. Intraneural recordings have, however, yielded varying results; both a normalization and a remaining hyperactivity have been obtained in cardiac transplant recipients, the latter being attributed to cyclosporine treatment. METHODS AND RESULTS: To circumvent the methodologic variation associated with different patient groups in cross-sectional studies, a longitudinal study design was employed in this study. Intraneural recordings of muscle sympathetic nerve activity in 21 heart failure patients were performed before, and repeatedly during the first year after, heart transplantation. Before surgery, muscle sympathetic nerve activity was augmented in all patients (78 +/- 4 bursts/min, 90 +/- 2 bursts/100 heartbeats). Both muscle sympathetic nerve activity burst frequency (burst/minute) and burst incidence (bursts/100 heartbeats) decreased rapidly following surgery. One month after surgery, burst frequency was reduced by 35% (51 +/- 5 bursts/min P < .05), whereas burst incidence decreased by 32% (61 +/- 5 bursts/100 heartbeats, P < .05). This decrease remained unchanged up to 1 year after surgery. The fall in posttransplant muscle sympathetic nerve activity was similar in transplant recipients who developed hypertension during the course of the study (n = 12) and those who remained normotensive (n = 9). CONCLUSIONS: The sympathoexcitation recorded in patients with heart failure was rapidly and substantially reduced after cardiac transplantation despite cyclosporine treatment, most likely reflecting improved central and peripheral hemodynamics.

Cyclosporine↗

PubMed1997

Tobacco smoking and risk of haematological malignancies in adults: a case-control study.

A retrospective study was conducted in 1216 cases to investigate the possible association between tobacco smoking and the risk of haematological malignancies. A small, but not significant, increase in malignancy was observed in smokers. Significant association was demonstrated between tobacco smoking and acute nonlymphoblastic leukaemia, and myelodysplastic syndromes. The duration and amount smoked increased the risk; heavy smokers presented significant positive associations with overall malignancies, acute nonlymphoblastic leukaemia, myelodysplastic syndromes, and monoclonal gammopathy of undetermined significance, whereas light smokers did not present any significant association. These data support a causal relationship between certain haematological malignancies and tobacco smoking. Further research is needed to examine the risk according to dose-response effect, and the variation in risk according to the histological subtype of the malignancy.

Adolescent↗

PubMed1997

Cosinor analysis of circadian peak expiratory flow variability in normal subjects, passive smokers, heavy smokers, patients with chronic obstructive pulmonary disease and patients with interstitial lung disease.

Peak expiratory flow (PEF) presents a circadian rhythm with a maximum in the afternoon, and a significant variability in its diurnal variations has been reported in normal subjects and in chronic obstructive pulmonary disease (COPD). In order to investigate whether passive smoking, active tobacco smoking, COPD and interstitial lung disease (ILD) are associated with changes in the circadian rhythm of PEF, five groups of adult male subjects, comparable for age, weight and height, were studied: group A: 30 clinically healthy subjects who never smoked, group B: 30 subjects passively exposed to tobacco smoking, group C 30 heavy smokers (> 20 cigarettes daily for at least 5 years), group D: 30 patients with nonasthmatic COPD (emphysema and/or chronic bronchitis), and group E: 15 patients with ILD (pneumoconiosis). Active tobacco smoking and exposure to passive smoking were assessed by the determination of the urinary cotinine concentration. A portable spirometer was used to measure PEF over a whole day, at 0.00, 6.00, 8.00, 10.00, 12.00, 14.00, 16.00, 18.00, 20.00, 22.00, and 24.00 h, all subjects leading a normal life. The 'mean cosinor' method was used for statistical analyses; the PEF variability was evaluated by the amplitude percent mesor (daily mean). All groups showed diurnal fluctuations in PEF values with significant (p < 0.05) circadian rhythms. The peaks of PEF rhythms occurred in the early afternoon, without significant (p > 0.05) differences between the groups. The cosinor mean was significantly (p < 0.05) lower in heavy smokers, in passive smokers, and in COPD patients than in controls. Controls, passive smokers, heavy smokers, COPD and ILD patients presented a PEF amplitude percent mesor (95% confidence limits) of 6.26% (range 4.57-7.95), 7.79% (range 5.07-10.51), 12.60% (range 7.61-17.59), 17.19% (range 10.18-23.50), and 3.98% (range 2.09-5.87), respectively, with significant differences (p < 0.05) between all groups, except between controls and passive smokers. These data suggest that tobacco smoke, both passive and active, does not modify the circadian peak of PEF, but modifies significantly its mesor and amplitude. In this respect, heavy smokers have the same pattern of COPD: lower mesor and greater amplitude; passive smokers present an intermediate situation. An increased diurnal variability in PEF could be considered as an early index of tobacco smoke damage and of developing COPD. When studying diurnal PEF variability, active and passive smoking habits should be considered.

Adult↗

PubMed1997

The natural history of monoclonal gammopathy of undetermined significance. A 5- to 20-year follow-up of 263 cases.

Patients with monoclonal gammopathy of undetermined significance (MGUS) have a serum monoclonal component (M-component), but no evidence of multiple myeloma, macroglobulinaemia, amyloidosis or other plasma cell proliferative disease. A long-term follow-up study (median 11.5 years) has been carried out in 263 cases of MGUS, 159 males (60.5%) and 104 females (39.5%), aged 40-89 years (median 66.5 years). The actuarial probability for malignant transformation was 6.1, 15.4 and 31.3% at 5, 10 and 20 years, respectively. At the final evaluation, 157 patients (59.7%), 119 (45.3%) of whom with no increase and 38 (14.4%) with an increase in serum M-component, died of causes unrelated to MGUS and without development of any plasma cell proliferative disease; 47 patients (17.9%) were still alive without increase in M-component; 11 patients (4.1%) were still alive and at follow-up presented values of serum M-component > 30 g/l without any evidence of plasma cell proliferative or lymphoproliferative disease; 48 patients (18.3%) developed multiple myeloma (35 cases, 13.1%), solitary plasmacytoma of the bone (2 cases, 0.8%), macroglobulinaemia (4 cases, 1.6%), malignant lymphoma (3 cases, 1.2%), amyloidosis (2 cases, 0.8%), chronic lymphocytic leukaemia (1 case, 0.4%), and plasma cell leukaemia (1 case, 0.4%). The patients developing multiple myeloma, solitary plasmacytoma, macroglobulinaemia and plasma cell leukaemia had an increase in serum M-component, whereas no increase was found in malignant lymphoma, amyloidosis and chronic lymphocytic leukaemia. These findings and the data in the literature suggest that MGUS could be considered a preneoplastic condition; since no clinical and laboratory features are able to identify in advance the patients at high risk of disease progression, each patient must be followed up indefinitely.

Adult↗

PubMed1997

No influence of aging on the circadian rhythm of erythropoietin in healthy subjects.

The diurnal rhythm in the circulating serum levels of erythropoietin (Epo) was investigated in a group of 20 clinically healthy subjects aged 30-55 years and in a group of 20 healthy subjects aged 55-75 years. Venous blood samples were drawn during the span of a whole day every 4 h, starting from midnight, for the determination of serum Epo levels by radioimmunoassay. Statistical analysis was carried out by means of the 'cosinor' method. Both groups presented a significant (p < 0.05) circadian rhythm in serum Epo levels, with maximum in the afternoon. The younger subjects had significantly (p < 0.05) higher mean daily levels and higher diurnal variations of serum Epo than older subjects; no difference (p > 0.05) was found between the groups regarding the peaks of the rhythms. These data confirm the presence of a circadian rhythm in serum EPO levels and suggest that the aging process does not influence the physiological diurnal fluctuations but modifies the mean daily levels and the amplitude of the diurnal variations, such as it occurs for many other variables. This behavior is an index of aging, but does not seem to have clinical implications.

Adult↗

PubMed1997

Diurnal rhythm of serum erythropoietin circulating levels in chronic obstructive pulmonary disease.

OBJECTIVE: Since erythropoietin (Epo) presents a diurnal rhythm in its circulating serum levels and it is reported increased in patients with chronic obstructive pulmonary disease (COPD), the circadian rhythm of Epo was investigated in a group of 40 normocytemic patients with chronic obstructive pulmonary disease compared with 40 clinically healthy subjects. METHODS: Venous blood samples were drawn in each subject during the span of a whole day every four hours, starting from midnight, for the determination of serum Epo levels by RIA. Statistical analysis was carried out by chronograms and by means of the "cosinor" method. RESULTS: The control group presents a significant (p < 0.001) circadian rhythm in serum Epo levels, with maximum in the afternoon, whereas no rhythm (p > 0.05) is detected in the patient group. This has significantly (p < 0.05) higher mean daily levels and lower diurnal variations of serum Epo than the control group; a significant (p < 0.05) difference exists between the two groups regarding the peaks of rhythms. CONCLUSION: These data confirm the presence of circadian rhythm in serum Epo levels and suggest that the COPD, by daytime hypoxemia with associated severe nocturnal desaturation, is associated with increased serum Epo levels both by day and by night, so that the physiological circadian rhythm is lost in these patients.

Adult↗