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Biomedical subjects

A Donato

Publications and source records attributed to A Donato.

At least 19 recordsLinked to original sources
PubMed1999

Endosonography in the diagnosis of "blue rubber bleb nevus syndrome": an uncommon cause of gastrointestinal tract bleeding.

Blue rubber bleb nevus syndrome is a rare condition characterized by the presence of multiple angiomatic lesions of the skin. These are associated with similar lesions in other organs, namely in the gastrointestinal tract, causing anemia through chronic bleeding. We describe the case of a 72-year-old woman with microcytic anemia. A barium study revealed irregular lacunae in the distal esophagus. A subsequent endoscopy showed blue nodular lesions similar to angiomas of the esophagus and stomach fundus. Endosonography confirmed its angiomatic nature. Exploration of other organs, using magnetic resonance and cranial computed tomography, did not reveal the presence of this type of lesion. In physical examination, two angiomatic lesions were observed on the face and lips, respectively. These were blue in color and compressible, leaving an empty wrinkled sac that rapidly refilled, typical of angiomas.

Aged↗
PubMed1999

Ticlopidine-induced prolonged cholestasis: a case report.

We report a case of ticlopidine-induced prolonged cholestasis in a 60-year-old man with no previous hepatobiliary disease who presented with sudden right upper abdominal pain, jaundice and pruritus three months after starting ticlopidine therapy. Other drugs taken by the patient were not considered probable causes. The diagnostic evaluation showed no biliary obstruction and other possible causes of intra-hepatic cholestasis were excluded. The liver biopsy showed a cholestatic hepatitis with bile duct damage. The disease ran a severe and protracted course, but symptoms and jaundice eventually subsided five months after drug withdrawal. More than a year later, relevant abnormalities of liver function tests consistent with anicteric cholestasis still persist, fulfilling criteria for a minor form of drug-induced prolonged cholestasis. This syndrome has been reported infrequently in relation to several drugs, mainly chlorpromazine, and only once with ticlopidine.

Cholestasis↗
PubMed1999

Electromagnetic interference of digital and analog cellular telephones with implantable cardioverter defibrillators: in vitro and in vivo studies.

The present study examines the potential electromagnetic interference effects induced by cellular telephones on ICDs. We developed ad hoc protocols to conduct both in vitro and in vivo trials on most of the implantable cardioverter defibrillators available on the international market. Trials were conducted with three cellular telephones: two GSM (Global System for Mobile Communication) and one TACS (Total Access Communication System). A human trunk simulator was used to carry out in vitro observations on six ICDs from five manufacturers. In vivo tests were conducted on 13 informed patients with eight different ICD models. During the trials in air, GSM telephones induced interference effects on 4 out of the 6 cardioverter defibrillators tested. Specifically, pulse inhibition, reprogramming, false ventricular fibrillation, and ventricular tachycardia detections occurred, which would have entailed inappropriate therapy delivery had this been activated. Effects were circumscribed to the area closely surrounding the connectors. When the ICD was immersed in saline solution, no effects were observed. Three cases of just ventricular triggering with the interfering signal were observed in vivo.

Aged↗
PubMed1997

Interaction between polyalkylcyanoacrylate nanoparticles and peritoneal macrophages: MTT metabolism, NBT reduction, and NO production.

PURPOSE: The nature of interactions between macrophages and drug carriers is of primordial importance either in the design of more effective therapeutic strategies for macrophage-associated pathogenesis or in establishing new approaches for pharmacological action avoiding macrophages. METHODS: Polyalkylcyanoacrylate nanoparticles (PMCA, PECA, PBCA and PIBCA nanoparticles) were assayed for their toxicity on peritoneal resident and thioglycolate-elicited macrophages. Cellular viability was assessed by MTT tetrazolium salt assay, oxidative burst by NBT reduction and NO production by nitrite evaluation. RESULTS: The nanoparticles tested led to cellular morphological modifications and induced toxicity in both types of macrophages in culture. The polyalkylcyanoacrylate nanoparticles uptake by peritoneal macrophages caused an increase in respiratory burst, as assessed by the NBT reduction assay, and induced the release of soluble toxic factors to the culture medium. The association of LPS with the PMCA nanoparticles significantly stimulated the production of nitric oxide (NO) by resident macrophages. In contrast, the association of PBCA nanoparticles with LPS does not increase the nitrite production as compared with LPS alone, which may be due to a different physico-chemical interaction between LPS and the two types of polymers. CONCLUSIONS: In cultured mice peritoneal macrophages, nanoparticles of PACA induce the production of oxygen reactive products, which cause changes in the cell metabolism of both resident and elicited macrophages. PMCA nanoparticles in association with LPS significantly increase the expression of the inducible isoform of nitric oxide synthase, leading to the release of large amount of NO, which may be highly cytotoxic to the cultured cells in the presence of peroxide generated from the oxidative burst.

Animals↗
PubMed1997

Oesophageal lichen planus.

Lichen planus is a common skin and mucosal disease, with very rare symptomatic oesophageal involvement. We report a case of painful dysphagia due to oesophageal lichen planus in a 60-year-old woman who also had oral, cutaneous and genital lichen planus lesions. Steroid treatment produced considerable improvement of all lesions and a rapid symptomatic remission.

Anti-Inflammatory Agents↗
PubMed1997

Severe acute liver failure as the initial manifestation of haematological malignancy.

Acute liver failure is rarely secondary to lymphoma or leukaemia and it is extremely uncommon as the initial presentation of malignancy. We report a case of a young adult patient with severe acute liver failure referred for liver transplant, in which a Burkitt acute lymphoblastic leukaemia was diagnosed by bone marrow examination. A complete recovery and long remission were obtained with chemotherapy.

Adult↗
PubMed1996

Mesenteric arteriovenous fistula causing portal hypertension and bleeding duodenal varices.

We report a case of portal hypertension associated with a non-traumatic arteriovenous fistula, presenting with bleeding duodenal varices. The patient was admitted for melaena. Emergency endoscopy showed oesophageal varices with no signs of recent bleeding and with no blood in the upper gastrointestinal tract. Arteriography of the coeliac axis and superior mesenteric artery failed to detect any bleeding source. Endoscopy was repeated because of persistent bleeding and revealed active bleeding from varices in the distal duodenum. The patient underwent surgery and a large paraduodenal varicose vein associated with an arteriovenous fistula was found. Resection of the paramural varix and surgical occlusion of the arteriovenous fistula were effective in the control of bleeding. Liver biopsy revealed mild portal fibrosis without cirrhosis. Three years after surgery the patient still has oesophageal varices but has not had recurrent bleeding. There was regression of intraduodenal varices.

Aged↗
PubMed1996

Electromagnetic interference of analog cellular telephones with pacemakers.

The aim of this study was to verify whether there is a public health risk from the interference of analog cellular telephones with pacemakers. We used a human trunk simulator to reproduce an actual implant, and two cellular telephones working with the TACS (Total Access Communication System) standard. Results showed that the electromagnetic field radiated from the analog cellular telephones interfered with a large number of the pacemakers tested (10/25). When the telephone antenna was in close proximity to the pacemaker head, pacemaker desensitizing and sensitizing and pulse inhibition was detected at the moment of an incoming call and throughout ringing. In the worst case of pulse inhibition, the pacemaker skipped three nonconsecutive beats and then resumed its normal pacing, while the desensitizing and sensitizing phenomena persisted as long as the interfering signal was on. Pulse inhibition was also observed when the connection did not succeed. Maximum sensing threshold variation was about 186% (increase) and 62% (decrease) for desensitizing and sensitizing phenomena, respectively. It was also demonstrated that the signal emitted by analog cellular telephones during the crossing of contiguous cells could induce pacemaker pulse inhibition, but under our experimental conditions this event did not seem to pose a risk for the pacemaker patient.

Electromagnetic Fields↗
PubMed1996

Irregular sinus parasystole due to intermittency and modulation of parasystolic activity.

A case of intermittent sinus parasystole in which the parasystolic focus is protected from the dominant sinus rhythm only during the second half of its intrinsic cycle is reported. In addition, a modulating (i.e., electronic) effect is often clearly exerted from the dominant rhythm upon the focus during the protected period. Coexistence of both modulation and intermittency in sinus parasystole, as well as a modulating effect limited to the second part of the parasystolic cycle, have not been previously reported.

Arrhythmia, Sinus↗
PubMed1995

Do European GSM mobile cellular phones pose a potential risk to pacemaker patients?

A series of in vivo trials were carried out in order to verify whether the electromagnetic field radiated by GSM (Groupe Systemes Mobiles) mobile cellular phones might affect implanted pacemakers. Two European GSM phones of 2-watt power were tested and trials conducted on 101 pacemaker implanted outpatients attending day hospital for routine check-up, who volunteered for trials. Forty-three pacemaker models from 11 manufacturers were tested in all. When the sensing threshold of the pacemakers was set at a minimum and the antenna of the phone was in direct contact with the patient's chest, interference was detected for 26 implanted pacemakers. Specifically, pulse inhibition in 10 of 101 cases, ventricular triggering in 9 of 46 DDD-VDD pacemakers, and asynchronous pacing in 4 of 52 devices. Pulse inhibition was also observed combined with asynchronous pacing in 1 of 52 cases and with ventricular triggering in 2 of 46 cases. Minimum effect duration was ca. 3 seconds but in 6 cases effects continued as long as the interfering GSM signal was on. No permanent malfunctioning or changes in the programmed parameters were detected. Whenever interference was detected, trials were repeated to determine the maximum sensing threshold at which interference persisted (with the antenna in contact with the skin over the pacemaker). Then maximum distance between antenna and pacemaker at which interference occurred was determined at pacemaker maximum and minimum sensing threshold. Under our experimental conditions electromagnetic interference effects were detected at a maximum distance of 10 cm with the pacemaker programmed at its minimum sensing threshold.(ABSTRACT TRUNCATED AT 250 WORDS)

Electricity↗
PubMed1994

Histochemical reactions of the secretory cells of the Stannius corpuscles in Palamys sarda L.

Two cell types have been identified in the Stannius corpuscles of Palamys sarda L. They are distinguished by the presence or absence of granules. Histochemical studies have shown that the granules contain proteins with - NH2 radicals, glycoproteins, sulfomucins, carboxymucins and cholesterol. The two cell types might represent different stages of a single functional cell type.

Animals↗
PubMed1993

[The allorhythmic distribution of ectopic ventricular beats. Observations on the electrogenesis and dynamics of concealed ventricular extrasystole].

BACKGROUND: A regular distribution of ventricular ectopic beats is thought to be a relatively uncommon phenomenon, known as "concealed extrasystole". Several experimental studies suggest that the phenomenon originates from a "protected" ventricular focus. The aim of the present study was to evaluate the 24-hour ECG monitoring incidence of ventricular concealed extrasystole in patients with highly frequent ventricular ectopic beats, looking for signs useful in postulating the electrogenesis of the arrhythmia. METHODS: The 24-hour ECGs of 10 patients (pts) with highly frequent ventricular extrasystoles were analysed, searching for significant sequences in the distribution of ectopic beats (i.e., ectopic beats separated by a number of interectopic sinus beats fulfilling one of the formulas of concealed extrasystole). RESULTS: Five cases (50%) showed an allorhythmic distribution resulting in a prevalent pattern of concealed bigeminy (2n-1) in 3 cases, and concealed trigeminy (3n-1) in 2 cases. The phenomenon, however, showed a dynamic behaviour, alternating the distributions from patterns of concealed bigeminy to concealed trigeminy or less common patterns, and vice versa. The evidence of the pure ectopic cycle and mathematically related interectopic intervals in 2 cases, the variability of coupling intervals, and the presence of fusion beats in the remaining 3 cases, strongly suggests a parasystolic origin of the phenomenon. CONCLUSIONS: The results suggest the following: Concealed extrasystole is a relatively common phenomenon, at least in patients with highly frequent ventricular extrasystoles; the phenomenon, however, is somewhat underestimated due to prevalent quantitative, instead of qualitative, Holter monitoring analyses. Among patients with allorhythmically distributed ventricular extrasystoles, none showed only one pattern of distribution. In fact, each single patient showed two or more patterns throughout the 24-hour recordings. Changes from one pattern to another is governed by several factors, such as sinus heart rate and/or the influence of electrotonic "modulation" upon the ectopic focus. Ventricular extrasystoles with regular allorhythmic distribution show a significantly higher variability of coupling intervals than the others (p = 0.005).

Adolescent↗
PubMed1992

Irregular ventricular tachycardia: a possible manifestation of longitudinal dissociation within the reentry pathway.

Sustained monomorphic ventricular tachycardia is usually regular; that is, it is associated with constant R-R intervals. In several cases, however, the cycles of ventricular tachycardia are more or less variable. Fifty-four cases of sustained monomorphic ventricular tachycardia were evaluated in order to assess whether tachycardia was regular. Nine cases were defined as irregular (i.e., the R-R cycles varied by more than 40 msec throughout a 1-minute recording). In five cases tachycardia was "regularly irregular," since the R-R cycles could be divided into two separate groups: the group of long cycles and that of short cycles. In these cases the variability manifested according to a defined and constant pattern: bigeminal pattern (alternation of short and long cycles), trigeminal pattern (two short cycles followed by a long cycle), and so on. The regular variability of tachycardia cycle length suggests one of the following possibilities. (1) There are two alternative circuits (a short circuit and a long circuit) that share the same exit pathway. Whenever the reciprocating impulse runs through the short circuit, the R-R cycle is short; but if a block in the short circuit occurs, the impulse runs through the long circuit, resulting in a long R-R cycle. (2) There is a longitudinal dissociation within the reentry circuit; two separate pathways with different inherent conduction velocities are present. When the impulse runs through the fast pathway, the R-R cycle is short; whereas when a block in the fast pathway occurs, the impulse traverses the slow pathway, resulting in a long R-R cycle.

Electrocardiography↗
PubMed1992

Electrocardiographic changes associated with haematocrit variations.

The electrical resistivity of intracardiac blood is less than the resistivity of the surrounding tissues. This affects the transmission of cardiac forces to the body surface: the radial forces are enhanced, whereas the transmission of tangential forces is diminished (the Brody effect). Blood resistivity is directly related to haematocrit, hence, haematocrit changes are expected to affect the transmission of cardiac forces, resulting in changes in QRS complex voltage. To assess this hypothesis, a 12-lead electrocardiogram was recorded in 40 patients affected by thalassaemia before and after a transfusion of concentrated red cells. The voltage of each QRS component was carefully measured in every lead, and the sum of all R wave amplitudes (sigma R) was calculated. The post-transfusional electrocardiogram reflected a significant decrease in the R wave amplitude in every lead. sigma R also decreased, whereas S wave amplitude in lead V6 increased. A negative correlation between the ratio of haematocrit pre/post transfusion and that of the corresponding sigma R values was also observed (r = -0.434; P less than 0.01). An increase in haematocrit is therefore associated with a decrease in R wave amplitude. These findings explain why several patients with high haematocrit manifest relatively low voltage QRS complexes.

Adolescent↗