Biomedical subjects

S Luca

Publications and source records attributed to S Luca.

At least 19 recordsLinked to original sources

PubMed2004

Probing membrane protein orientation and structure using fast magic-angle-spinning solid-state NMR.

One and two-dimensional solid-state NMR experiments are discussed that permit probing local structure and overall molecular conformation of membrane-embedded polypeptides under Magic Angle Spinning. The functional dependence of a series of anisotropic recoupling schemes is analyzed using theoretical and numerical methods. These studies lead to the construction of a set of polarization dephasing or transfer units that probe local backbone conformation and overall molecular orientation within the same NMR experiment. Experimental results are shown for a randomly oriented peptide and for two model membrane-peptides reconstituted into lipid bilayers and oriented on polymer films according to a method proposed by Bechinger et al.

Anisotropy↗

PubMed2001

Secondary chemical shifts in immobilized peptides and proteins: a qualitative basis for structure refinement under magic angle spinning.

Resonance assignments recently obtained on immobilized polypeptides and a membrane protein aggregate under Magic Angle Spinning are compared to random coil values in the liquid state. The resulting chemical shift differences (secondary chemical shifts) are evaluated in light of the backbone torsion angle psi previously reported using X-ray crystallography. In all cases, a remarkable correlation is found suggesting that the concept of secondary chemical shifts, well established in the liquid state, can be of similar importance in the context of multiple-labelled polypeptides studied under MAS conditions.

Carbon↗

PubMed2001

Bioavailability and antioxidant activity of some food supplements in men and women using the D-Roms test as a marker of oxidative stress.

Most antioxidants show contradictory behaviors because in the biological environment, for unpredictable reasons, they can become prooxidants. Recently, a new simple method to monitor oxidative stress in serum was developed. This test detects the derivatives of reactive oxygen metabolites (D-Roms). Hydroperoxides are converted into radicals that oxidize N,N-diethyl-para-phenylendiamine and that can be detected through spectrophotometric procedures as U.CARR. (Carratelli units). One U.CARR. corresponds to 0.8 mg/L hydrogen peroxide. In normal subjects U.CARR. values range from 250 to 300. Values outside this range indicate a modification of the prooxidant/antioxidant ratio. On the basis of this method, we tested three different formulas of antioxidants (F1, F2, F3) in 14 apparently healthy volunteers (11 men and 3 women). Formula 1 was composed of 5 mg zinc, 48 microg selenium, 400 microg vitamin A (as retinol acetate), 50 microg beta-carotene, 15 mg vitamin E (as dl-alpha-tocopheryl acetate) and 10 mg L-cysteine. Formula 2 was composed of 30 mg bioflavonoids from citrus, 30 mg vitamin C (as L-ascorbic acid), 10 mg coenzyme Q(10) and 1 mg vitamin B-6 (as pyridoxine hydrochloride). Formula 3 was composed of Formula 1 plus Formula 2. Each formula was prepared in dry capsules (formulation D1, D2, D3) or in a fluid form (formulation P1, P2, P3). Each formulation was administered for 1 wk in a crossover design. A 15% deviation of U.CARR. levels was chosen as the cut-off value for a significant change in oxidative stress. Formulas F1 and F3 reduced mean U.CARR. levels in most of the treated subjects (t test, P < 0.05), whereas F2 was not active. Fluid formulations were more active than dry formulations (chi(2) test, P < 0.05). In some cases, a slight increase in oxidative stress was detected. These minimal increases were not related to any particular antioxidant formula. In one subject only, the administration of the dry formulation (D1), increased oxidative stress to a level that reached the cut-off value. In conclusion, when antioxidants are taken in combination at low dosages they reduce oxidative stress, and little relevant prooxidant activity is detectable.

Adult↗

PubMed2001

[Treatment of chronic arterial occlusive disease of the lower limbs with propionyl-1-carnitine in elderly patients].

BACKGROUND: Atherosclerosis is the most common pathology affecting the arterial system in elderly patients and arterial occlusive disease of the lower limbs represents one of the most severe complications. Intermittent claudication is the clinical expression of the ischemia underlying this arterial disease. Patients suffering from this complication present altered homeostasis of carnitine that results, by means of various mechanisms, in an alteration of the oxidative processes and damages the oxidative phosphorylation of the skeletal muscle. The effects of treatment with propionyl-l-carnitine (PLC) in a group of elderly patients with intermittent claudication (IC) are studied. METHODS: 39 elderly patients with IC were enrolled in an open study. The diagnosis was made using arterial colour ultrasonography of the lower limbs and patients were asked to perform the treadmill test. All patients received 300 mg i.v. PLC a day for 2 weeks and 1 g twice a day per os for 18 weeks. Patients presenting heart, respiratory or other problems restricting physical exercise were excluded from the study. RESULTS: After 5 months of treatment an improvement was obtained in the distance after which IC appeared (from 213+/-8 m to 357+/-13 m) and the maximum distance covered (from 307+/-12 m to 549+/-23 m). CONCLUSIONS: The results of this study allowed us to evaluate the efficacy of this drug on the severely disabling pain affecting the quality of life of patients, thus enabling the maximum distance covered by these patients to be increased. Moreover, the drug was well tolerated (only two patients reported slight collateral effects ascribed to the drug) and safe to use. It represents a valid conservative, non-surgical treatment which can be administered to all patients with intermittent claudication.

Aged↗

PubMed2001

A method for evaluating the thermal threshold in patients with Raynaud's syndrome living in temperate areas. A report of three cases.

BACKGROUND: The concept of "thermal threshold" in Raynaud's syndrome was theorized in 1990 by Pratesi as the ambient temperature below which an attack of vasospasm is more likely to be provoked, though so far it has not yet been proved to be a reality. Our preliminary report of two cases, whose attacks were compared with the daily maximum temperatures, showed results suggestive of the existence of this parameter. METHODS: We asked a third female patient with Raynaud's syndrome of the hands and feet to keep note of the time, days and modalities of the phenomena, for at least three months including the summer. Data of six and five months from Cases 1 and 2 respectively, not including the times at onset, were reconsidered. The data available from all cases were compared to the true daily mean temperature. The data of the new Case 3 were also compared with the hourly temperatures on each day over the period of study. All calculations referred to the estimated temperature to be expected from the difference in altitude between the weather stations and the usual and temporary residences. RESULTS: The mean thermal threshold was 17.166 degrees C in the less severe Case 1 and 28.438 degrees C in Case 2 (complicated by gangrene). In Case 3, the mean and hourly thresholds were 26.740 and 26.807 degrees C for the hands, and 25.092 and 23.807 degrees C for the feet, respectively. CONCLUSIONS: This report is suggestive, although not conclusively, of the existence of a thermal threshold, which is higher in the more severe cases. Further research is required.

Adult↗

PubMed2001

[Behaviour of free radicals in Alzheimer's disease].

BACKGROUND: The objective of this study is to evaluate the oxidative stress status in patients affected by Alzheimer's disease, considering the role played by the free radicals in the progression and determination of this disease. METHODS: We have studied 13 patients aged between 65 and 84 years and diagnosed with Alzheimer's disease on the basis of Brain CT scan or MRI results, PTEA (uditive mapped slow potential waves), EEG analysis, evaluation questionnaire (MMSE, ADAS), free radicals levels. RESULTS: This study proved the presence of an oxidative stress status in all patients studied, showing an interaction between the disease and oxidative status. A reduction of the free radicals levels after therapy with determinable anti radicals has also been observed. CONCLUSIONS: The existence between Alzheimer's disease and oxidative stress has already been demonstrated. This study is a contribution to this orientation. Further studies are suggested on the preventive effects, but particularly to demonstrate if the use of antioxidants may be able to decrease or stop the evolution of this disease.

Aged↗

PubMed2000

Treatment of arterial hypertension in the elderly with diltiazem vs ramipril.

BACKGROUND: Around 40% of the elderly population suffer from arterial hypertension. An effective antihypertensive treatment is therefore required. Calcium antagonists are used to treat hypertension because, owing to their mechanism of action, they can provoke systemic, as well as coronary vasodilatation. In this study the authors aimed to evaluate the activity and tolerability of diltiazem compared to ramipril in a group of elderly patients suffering from essential arterial hypertension. METHODS: A controlled single-blind study was performed in which patients were randomly assigned to one of two groups, A and B, consisting of 25 patients each, treated respectively with 300 mg sustained-release diltiazem or 5 mg ramipril in a single daily dose. The study lasted 6 months and evaluated systolic and diastolic pressure and heart rate. RESULTS: The evolution was positive in all patients in Group A and most patients in Group B, with the normalisation of both systolic and diastolic values. Heart rate showed a more persistent fall in Group A, but this was expected owing to the mechanism of action of diltiazem. No patient in Group A had to suspend treatment, whereas one patient in Group B had to interrupt therapy following the onset of a persistent cough. CONCLUSIONS: Both treatments resulted in similar changes in systolic and diastolic arterial blood pressure. In the light of these results, it can be affirmed that, at an oral dose of 300 mg/day, sustained-release diltiazem was found to be effective and well tolerated in the treatment of mild to moderate essential arterial hypertension in the aged.

Age Factors↗

PubMed2000

Helicobacter pylori eradication in elderly patients.

BACKGROUND: The elderly population is rising constantly in industrialised countries. Accord-ing to ISTAT, within the next 15 years the number of over-80-year-olds in Italy will top 2.6 million. In the elderly, the incidence of peptic ulcer tends to increase with age. An important etiological role has recently been attributed to helicobacter pylori (HP) which has been identified as a risk factor for the various forms of gastric cancer. METHODS: The study was carried out in 57 patients (45 with HP+ duodenal ulcer and 12 with HP+ gastric ulcer). Diagnosis was made on the basis of endoscopic tests, histological tests and urea breath test. Patients were treated orally with clarithromycin 500 mg twice a day for 14 days), amoxycillin (1 g twice a day for 14 days) and omeprazole (20 mg once a day for 30 days). RESULTS: The results showed an eradication of HP in 89% of duodenal ulcer patients and 83.3% of peptic ulcer patients. CONCLUSIONS: The treatment protocol used in this study achieved percentages of eradication that are comparable to those reported by other authors using different protocols; the percentages were sufficiently high for the protocol to be regarded as efficacious and well tolerated by patients. In fact, the scarce incidence of undesirable effects and excellent patient compliance are of particular interest in view of the fact that elderly patients have a higher risk of side-effects.

Journal Article↗

PubMed2000

Enteral nutrition in patients with chronic neurological diseases.

BACKGROUND: Malnutrition is commonly considered an important risk factor that can produce a negative influence on the prognosis of patients with chronic neurological diseases. The reduced caloric or proteic intake due to the motor or cognitive dysfunction, the hypercatabolic state due to infections, the abnormal gastrointestinal motility are the main mechanisms responsible for a state of malnutrition. METHODS: Between January and December 1999 fourteen patients with chronic neurological diseases were treated. Ten of them had had a stroke, four due to Amyotrophic Lateral Sclerosis (ALS). After the evaluation of nutritional status the patients received enteral nutrition (EN) by placement of a nasointestinal feeding tube or a Bengmark tube. Glycaemia, blood urea nitrogen, serum creatinine, electrolytes, glycosuria, glutamic-oxalacetic and glutamic pyruvic transaminase were monitored in all patients. Polymeric enteral feeding was administered by an infusion pump. Standard nourished patients (7/14) received a 30 Kcal/kg/day support, the undernourished ones (6 low, 1 moderate malnutrition) received a 35-40 Kcal/kg/day support. RESULTS: The complete caloric supply was reached in three-four days. Both of the groups received continuous feeding infusion during hospitalization. For the patients who continued the nutritional support at home (3/14) refeeding was performed only during night-time. In the patients with stroke the optimal/standard weight was reached within one month. In these patients oral nutrition was started within 45 days of treatment taking into account the restored swallowing function. In the patients with ALS the improvement of nutritional standards was reached within the first month and complete restoration within the second/third month. CONCLUSIONS: On the basis of our experience enteral nutrition represents an effective refeeding procedure in patients with chronic neurological diseases.

Journal Article↗

PubMed1999

Helicobacter pylori-positive functional dyspepsia in elderly patients: comparison of two treatments.

The association of Helicobacter pylori and functional dyspepsia is not well defined. The role of H. pylori on dyspeptic symptoms is still controversial. The aim of this study is to confirm the efficacy of H. pylori eradication by two different commonly used treatment regimens, as well as to examine the improvement of the dyspeptic symptoms by eradicating H. pylori. H. pylori functional dyspepsia is prevalent in people over 60 years old. In this age group we treated 126 patients with bismuth plus metronidazole and amoxicillin (group A, 67 patients) versus omeprazole plus amoxicillin (group B, 59 patients). Results were statistically analyzed utilizing the Wilcoxon signed-rank test, McNemer test and chi-square test; P < 0.05 was considered significant. Two months after the end of therapy we observed an eradication rate of 66.1% in group A vs 64.3% in group B. All treated patients showed improvement in symptomatology. Although there was no significant difference between patients in whom H. pylori was or was not eradicated within the respective groups, when examining all H. pylori-positive patients versus H. pylori-negative posttreatment patients, there was a significant reduction (P < 0.05) in all four symptoms of functional dyspepsia measured. In conclusion, we suggest that patients treated with H. pylori-eradicating therapeutic regimens have an improvement in functional dyspepsia symptoms. We shall prefer the dual therapy as compared to the triple therapy. We believe that eradicating treatment to eradicate H. pylori in the elderly patients with H. pylori-related functional dyspepsia will reduce health care costs by reducing the number of subsequent visits.

Aged↗

PubMed1999

[Treatment of postmenopausal osteoporosis with etidronate].

BACKGROUND: Osteoporosis is a widespread social disease as it is considered to be the most common pathology affecting bone metabolism in the elderly. A group of patients suffering from post-menopausal osteoporosis have been treated with etidronate. METHODS: This controlled study was performed on 32 post-menopausal women aged between 53 and 66 suffering from post-menopausal osteoporosis, treated at the Department of Geriatrics of the University of Catania where patients mainly come from Sicily and Southern Italy. The diagnosis was made after clinical examination and humoral tests as well as computerised total body bone densitometry. Patients were treated according to an intermittent cyclic scheme which consisted in the administration of 400 mg etidronate per day for 14 days and 500 mg calcium carbonate per day for the following 76 days. This treatment had to be repeated for one year. Patients in the placebo group were not treated. RESULTS: The results of the study showed a significant increase of total body bone mineral density +5.6% (p = 0.009), with a considerable improvement of clinical symptoms. No significant variation was detected in the control group. CONCLUSIONS: On the basis of the results obtained, the conclusion is drawn that the intermittent cyclic treatment with etidronate is effective, well tolerated and with good compliance. Moreover, this drug proved to have no side effects.

Aged↗

PubMed1999

[Correlation between clinical-instrumental pattern in venous pathology (capillaroscopic classification of the medial peri-malleolar area)].

BACKGROUND: The high incidence of chronic venous insufficiency makes it quite an ordinary topic in the outpatients departments of vascular units. Furthermore, due to the discrepancy between symptoms and Doppler c.w reports, it is necessary to face this problem with the help of very sensitive instrumental methods. Therefore, the main aim of this article is to find out which method, among those used in the outpatients department of phlebology, is sensitive enough to establish a relationship between clinical and instrumental patterns in venous diseases. METHODS: Fifty-one subjects were studied: 44 affected by venous disease and 7 healthy subjects. All patients underwent clinical examination followed by classification by Widmer criteria, Doppler c.w., infrared photoplethysmography and capillaroscopy of the medial malleolus. RESULTS AND CONCLUSIONS: Capillaroscopy demonstrated to have the highest sensitivity, allowing to find out pathological alterations in subjects complaining of symptoms and with normal Doppler c.w. findings. Furthermore, the findings of venular networks (pathological) in the malleoli of healthy subjects, made it necessary to modify the current capillaroscopic classification (based upon three types of pictures: normal, reticular and halo formations), into a new extended version based on five steps, with three types of reticular sub-classes, in which the different gauge of the venules is satisfactorily related to the symptoms referred by the patients.

Adolescent↗

PubMed1999

[The determination of the thermal threshold in subjects with Raynaud's disease. A preliminary report of 2 clinical cases].

BACKGROUND: The onset of Raynaud's phenomenon is mainly provoked by cold stimuli which, in patients affected by Raynaud's disease, are milder than those able to provoke the same phenomenon in healthy subjects. Therefore, it is reasonable to theorize the existence of a "thermal threshold", below which it is more likely for a Raynaud's phenomenon to be provoked. The aim of this investigation is to determine whether a thermal threshold in Raynaud's disease exists and if it can be used as a practical tool for preventing the complications of Raynaud's disease (digital gangrene and ulcers), whose onset is strictly related to the frequency of the phenomena. METHODS: Two patients affected, respectively, by slight Raynaud's phenomenon secondary to peripheral neuropathy (Case 1), by severe Raynaud's phenomenon associated with mixed connective tissue disease (Case 2), were asked to write a note about the phenomena and the days of their onset, within a period of three months. Afterwards, all data were related to the daily ground maximum temperature occurred in the period of study. RESULTS AND CONCLUSIONS: These preliminary results show an interesting correlation between this new parameter and the clinical data, the thermal threshold being higher in more severe cases. It was equal to 22 degrees C in the patient affected by slight phenomenon (Case 1), and equal to 27 degrees C in the severe phenomenon (Case 2). This method for evaluating the thermal threshold in these two cases of Raynaud's disease (the greater the figure, the more severe the case) allowed both the clinical assessment of the pathology and the prevention of secondary complications.

Adult↗

PubMed1999

[Edema and skin ulcers of the lower limbs as a collateral effect of nifedipine. A clinical case report].

Nifedipine, as most calcium-antagonist drugs, is widely used for the treatment of angina pectoris and primary hypertension. Among its side effects, edema of lower limbs may expose patients to traumatic ulcers which become chronic. A case with painful ulcers and remarkable swelling of the ankles is reported. In this case, misdiagnosed as chronic venous insufficiency, good results were obtained with topical treatment and discontinuation of nifedipine. Leg ulcers and edema resolved in four months after ten years of disease history.

Aged↗

PubMed1999

Treatment of arterial hypertension in the elderly using enalapril.

BACKGROUND: Arterial pressure increases with age and is the most common chronic disease in the elderly, men and women alike. At present arterial hypertension is considered a social disease as it poses great health, economic and social problems. METHODS: A group of 50 patients of both sexes, between 66 and 83 years of age, suffering from essential arterial hypertension and treated with Enalapril administered at doses varying from 10 to 20 mg/day, for a period of 18 months, has been studied. RESULTS AND CONCLUSIONS: The results of this study showed that blood pressure values of almost all the patients treated normalised and left ventricular hypertrophy decreased in all patients with this complication.

Aged↗

PubMed1999

Advantages and disadvantages in the therapy with different types of interferon for chronic hepatitis C in the elderly patient.

BACKGROUND: HCV-related hepatitis is a pathology on the increase, and it is especially affecting patients above 60 years old. The only treatment for this disease is therapy with different types of interferon. In this paper the authors compare two of their experiences relative to the treatment of HCV-related chronic hepatitis in the elderly using two types of interferon: recombinant interferon alpha and interferon beta, in order to evaluate their efficacy and side effects. METHODS: The authors studied and compared two groups of elderly patients from Sicily and Calabria receiving medical care in the department of Geriatrics of the University of Catania. The first group consisted of 20 patients with an age ranging between 60 and 69 years, treated with recombinant interferon alpha; the second group consisted of 26 patients aged between 60 and 75 years treated with interferon beta. RESULTS: After an evaluation of the results, the authors argue that recombinant interferon alpha is preferable since the remission percentage is higher (75%). However, the interferon beta therapy proves to be almost without side-effects. CONCLUSIONS: Finally, the authors conclude that even in cases where there could be a possible higher exposure to side-effects linked to the use of recombinant interferon alpha, still, the risk/benefit ratio suggests that recombinant interferon alpha 2b should be used for the treatment of hepatitis in elderly patients, in the light of the results obtained.

Journal Article↗

PubMed1999

About a case of familial adenomatous polyposis.

The authors present a case of FAP, familial adenomatous polyposis. This condition comprises 3 different syndromes characterized by the development of numerous polyps in the colon. Other different expressions of the same genetic anomaly are: familial adenomatous polyposis coli, Gardner's syndrome and Turcot's syndrome. The main risk for these pathologies consists in the frequent cancer outcome, which usually occurs between the 4th and the 5th decade of life and, however, after about 12 years from the first diagnosis. The patient came to the authors' observation in the surgery room of the department of geriatrics, in the university of Catania, where patients from South Italy and Sicily are treated. He had a severe anemic condition and poor general health. At the time of the diagnosis the patient, 56 years old, was subjected to endoscopic investigations which showed extensive polyposis of the entire colon and of the stomach, later on typified as ''Familial polyposis''. He was then subjected to total colectomy and gastric polypectomy. Besides, the patient and his direct family members (4 children and 2 sisters) were also genetically screened. The results proved that the patient and 3 of his children presented a genetic mutation located in connection with one of the two alleles of the APC gene. The potentially cancerous evolution makes it necessary to perform a genetic screening of all direct relatives of patients affected by FAP in order to both uncover the genetic anomaly responsible for this pathology and to prevent cancer, which is the natural outcome of this disease.

Journal Article↗

PubMed1997

Clinical evaluation of the efficacy of pivagabine in the treatment of mood and adjustment disorders.

Depression and distress have in common hypercortisolism, a high turn-over of cerebral monoamines and a wide clinical variability. Results of a clinical open trial with pivagabine (4-[(2,2-dimethyl-1-oxopropyl) amino]butanoic acid, CAS 69542-93-4, Tonerg) on 22 young patients affected by dysthymic disorders and on 38 older patients affected by adjustment disorders following different stressors (mourning, retirement and recovery in institutions of assistance) are reported. Oral treatment with 1800 mg pivagabine lasting 30 days showed in both groups a significant improvement of the psychic state with variations from 50 to 80% of the criteria reported in the Hamilton Rating Scale for Depression (HDRS) and for anxiety (HARS) and in the Self-rating Anxiety Scale (SAS). Good tolerance of the drug and the complete absence of serious side effects considerably contributed to the clinical success.

Adjustment Disorders↗