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Biomedical subjects

S Perini

Publications and source records attributed to S Perini.

At least 19 recordsLinked to original sources
PubMed2003

Carotid stenting with filter protection. Correlation of ACT values with angiographic and histopathologic findings.

BACKGROUND AND PURPOSE: Filter cerebral protection during carotid stenting has been proposed as a new tool to reduce brain embolism. Angiographic findings (filter patency), pathological analysis of the collected materials inside the filters and coagulation parameters were analyzed to identify potential down sides in the use of these protection devices. METHODS: 29 consecutive endovascular treatments with filter cerebral protection in 27 patients affected by symptomatic internal carotid stenosis>70% were considered. Angiographic findings, activated clotting times and histopathologic specimens were recorded and correlated. RESULTS: Satisfactory dilatation of the stenosis was always achieved with a complication rate of 3% (1 transient neurological deficit). During the procedure, 9 filters (31%) appeared occluded, with temporary flow impairment. Histopathologic examination demonstrated material inside the filters in 86% of cases but this material was fibrin alone in 38% and plaque debris in 48%. Significant statistical correlation (p=0.009) was found between low activated clotting time and occlusion of the filter. CONCLUSION: Distal protection filters can collect plaque fragments occurring during carotid stenting. Significant proportion of the debris found in the filters consisted of thrombotic material. Precise monitoring of heparin anticoagulation is recommended to prevent filter occlusion.

Aged↗
PubMed2001

A novel method for isolation of Brachyspira (Serpulina) hyodysenteriae from pigs with swine dysentery in Italy.

Brachyspira (Serpulina) hyodysenteriae was isolated from 10 of 11 pigs with clinically suspected swine dysentery in six herds in northern Italy. All strains were successfully isolated in the selective blood agar modified medium with spectinomycin and rifampin (BAM-SR) currently used in our laboratory to isolate B. (S.) pilosicoli of human origin, after pre-treatment of intestinal material with spectinomycin and rifampin in foetal calf serum. Isolates had phenotypic characteristics typical of B. (S.) hyodysenteriae.

Animals↗
PubMed2001

[Endovascular treatment of carotid stenosis].

PURPOSE: To evaluate the efficacy and risks of endovascular treatment of carotid stenosis by percutaneous angioplasty and stenting, and to point out the potential indications of this technique compared to surgery. MATERIAL AND METHODS: From June 1996 to May 2000 we performed 84 endovascular treatments of epiaortic vessels in 79 patients with age ranging from 42 to 80. Sixty-eight symptomatic carotid stenosis greater than 70% were treated in 63 patients: 28 (41%) were post-surgical restenosis of the carotid bifurcation after carotid endarterectomy and 40 (59%) were primitive carotid stenosis. In 14 cases (20%) there was occlusion of the contralateral internal carotid artery. All the procedures were performed in the angiographic suite, with local groin anesthesia and with femoral arterial approach. Angioplasty alone was done in 9 cases (13%) while stents were positioned in 59 cases (87%). The stenoses were pre-dilated in 57% of the procedures, and post-dilated in 61%. In 8 patients (12%) the endovascular treatment was performed during distal cerebral protection. During the follow-up period patients underwent echo-Doppler studies after 24 hours, at 6 and 12 months. RESULTS AND DISCUSSION: The stenotic tracts were successfully dilated in all the patients, with a residual stenosis less than 30% in 94% of cases. We didn't observe any complication in the 30 days post-operative period. One permanent neurological deficit (1.5 %) and 1 transient neurological deficit (1.5%) were observed in 2 patients within 1 hour after treatment. Other 2 patients complained a transient ortostatic hypotension. Combined major stroke and death rates was of 1,5% after 30 days post-operative follow-up. The presence of associated occlusion of the contralateral internal carotid and the presence of cardiological failure or pulmonary insufficiency has not influenced the outcome. No new clinical complication has been reported during the follow-up while the restenosis rate after the endovascular procedure is 1.5%. Our results with the endovascular treatment of the carotid stenosis appear not significantly different from those reported by the main surgical publications and trails about the carotid endarterectomy. In particular in our experience the complication rate is similar to surgery, probably due to our patient selection and to the evolution of the materials for endovascular therapy. CONCLUSIONS: Our experience points out an improvement of the efficacy and safety of the endovascular technique. We confirm the indication of the angioplasty and stenting in post-surgical restenosis and in patients with high surgical risk. Moreover we think that the endovascular treatment can be performed also in primitive carotid stenosis with acceptable complication risk.

Adult↗
PubMed2000

Tesio catheter: radiologically guided placement, mechanical performance, and adequacy of delivered dialysis.

PURPOSE: Tunneled catheters are an alternative means of vascular access for patients in need of hemodialysis who cannot undergo dialysis through a surgical shunt. This study was undertaken to evaluate the performance of the Tesio dialysis catheter. MATERIALS AND METHODS: A prospective study of the Tesio catheter was performed. Follow-up data regarding catheter function and adequacy of dialysis were obtained from nine hemodialysis facilities. RESULTS: Seventy-nine Tesio catheters were placed in 71 patients. Immediate technical success was 99% (78 of 79 catheters). The procedure complication rate was 9% (seven catheters). Only two complications required intervention: one fatal air embolism and one chest wall hematoma. Sixty-seven catheters in 60 patients were followed up for a total of 4,367 catheter days. Overall, catheter-related infection occurred in 9% (six of 67 catheters). Primary catheter patency was 87% at 1 week, 82% at 1 month, 72% at 3 months, and 66% at 6 months. Mean blood flow was 286 mL/min immediately after insertion, 301 mL/min at 3 months, and 306 mL/min at 6 months. Adequate dialysis dose as reflected by a urea reduction ratio of 60 or more or a urea kinetic modeling, or Kt/V, value of 1.2 or more was observed on at least one occasion for 74% and 76% of catheters, respectively. CONCLUSION: The Tesio catheter is a reasonable means of vascular access for patients who undergo dialysis but are not candidates for surgical shunt placement.

Adolescent↗
PubMed1997

RNA transport in dendrites: a cis-acting targeting element is contained within neuronal BC1 RNA.

In nerve cells, a select group of RNAs has been localized to dendritic domains. Here we have examined dendritic RNA transport in sympathetic neurons in primary culture, using a microinjection protocol with neuronal BC1 RNA and with BC1-derived sequence segments. After cytoplasmic microinjection, full-length BC1 RNA was selectively transported to dendrites; in contrast, control RNAs such as nuclear RNAs and random-sequence irrelevant RNAs remained restricted to cytoplasmic areas proximal to the injection sites. Chimeric RNAs were constructed that contained the full-length BC1 sequence inserted upstream or downstream of the coding regions of nondendritic mRNAs. After microinjection, such chimeric RNAs were specifically targeted to dendrites; microinjected corresponding nonchimeric mRNAs were not. Dendritic transport of BC1 RNA was rapid: the average dendritic delivery rate within the first hour after microinjection was 242 +/- 25 microm/hr. Whereas a 5'-BC1 segment of 62 nucleotides was transported to dendrites to extents and at levels similar to full-length BC1 RNA, a 3'-BC1 segment of 60 nucleotides did not exit injected somata to any significant degree. A cis-acting dendritic targeting element is thus contained in the 5' part of neuronal BC1 RNA. These results demonstrate that mechanisms exist in neurons for fast and specific transport of selected RNAs to dendrites.

Animals↗
PubMed1997

Conservative treatment of a traumatic direct low-flow carotid-cavernous sinus fistula: a case report.

A case of a 17-year-old boy presenting with a traumatic carotid-cavernous sinus fistula (CCSF), associated with an intracavernous pseudo-aneurysm, is reported. On angiography, the CCSF proved to be a direct and low-flow shunt. Conservative management was chosen and definitive closure of the fistula was obtained in two months by daily self-compression of the common carotid artery.

Accidents, Traffic↗
PubMed1997

Endovascular treatment of pial AVMs: technical options, indications and limits in pediatric age patients.

Our study group consisted of 29 patients who underwent endovascular treatment for the presence of pial AVMs. The patients were treated with various embolization methods including "-free flow" embolization (2 cases); embolization with suture threads (2 mm long micro-emboli: 17 cases) and embolization with acrylic glue (10 cases). There were significant angio-architectural and AVM location differences between the pediatric and the adult patient groups. In pediatric patients, the more frequent AVMs were of the mono or few-pedunculated type, then simple direct fistulas and high-flow fistulous-plexiform AVMs and giant infra-tentorial or deep-seated malformations. In mono or few-pedunculated AVMs, the elected treatment was acrylic glue followed by radio-surgery achieving definitive cure in 3 cases. In direct AVFs and elevated flow AVMs, embolization with suture and acrylic glue offered definitive results. Treatment for infra-tentorial and deep-seated AVMs presented the greatest difficulty in pediatric patients. In two of them, embolization with glue enabled radiosurgery (giant cerebellar AVMs). Our experience did not confirm that current endovascular techniques provide definitive treatment in extensive, deep-seated AVMs. Each treatment, in children more so than in adults, requires a risk/benefit evaluation of the method taking into account the natural history data.

Adhesives↗
PubMed1997

Stereotactic radiosurgery for the treatment of arteriovenous malformations in childhood.

BACKGROUND: The main techniques and results in stereotactic radiosurgical treatment of endocranial AVM's are described and compared. The authors also report their preliminary experience in the treatment of 6 consecutive pediatric patients with intracerebral vascular malformations using gamma knife (GK) radiosurgery. METHODS: The various stereotactic radiosurgery methods currently used (charged-particle beam, modified linear accelerator, and GK) are described. At the Department of Neurosurgery in Verona, from February 1993 to February 1996, stereotactic GK radiosurgery was performed on 721 patients, including 20 of pediatric age (3%). Of the 78 AVMs, 7 (9%) were diagnosed in children. One patient was lost at follow-up. Among the remaining 6 children, there were 3 males and 3 females with a mean age of 12.3 years (range, 5-16 years). Treatment general anesthesia was needed only in 1 case. The AVM volume was always less than 10 cc. After completion of the procedure, children were discharged from the hospital the following day. RESULTS: The follow-up period ranged from 4 months to 29 months (median 18.8 months). The angiographic confirmed total obliteration is used as the end point of an AVM treated radiosurgically, and usually requires 2 to 3 years. All the patients are alive; four of the treated children are neurologically normal and one patient has clinically improved to a normal neurological status. The sixth patient has fixed neurological deficits that existed prior to treatment. Among the three cases with a follow-up period of over 2 years, complete obliteration has been angiographically confirmed in 2 patients and subtotal in 1 patient. In the three remaining patients with follow-up periods less than 2 years, serial MR images suggest subtotal obliteration in 2 cases and no significant change in one patient who had undergone treatment within the current year. To date, neither persistent GK radiosurgery-related complications nor bleeding following stereotactic radiosurgery has been described. CONCLUSIONS: The review of literature and our preliminary results suggest that also in children, as in adults, the use of stereotactically delivered irradiation represents a safe and effective technique obtaining complete obliteration of AVMs previously considered surgically inaccessible due to their location and poor response to resection and/or embolization.

Adolescent↗
PubMed1995

Bronchial artery embolization in the management of hemoptysis in cystic fibrosis.

Massive hemoptysis and/or recurrent expectoration of measurable amounts of blood are common complications of chronic bronchopulmonary infections in cystic fibrosis (CF). When conservative treatment fails to control bleeding, surgery or bronchial artery embolization (BAE) is frequently considered. We present our experience and long-term follow up of BAE in 14 CF patients (age range 15-39 years) with massive (6 subjects) and/or recurrent (8 subjects) hemoptysis not responsive to medical treatment. Seven had chronic hypercapnic respiratory failure. After angiographic evaluation, polyvinyl alcohol particles (Ivalon) were injected to embolize obviously enlarged bronchial arteries. Seventeen procedures were performed in 14 patients and 36 bronchial arteries were embolized. All the patients stopped bleeding immediately upon BAE. Most of the patients had postembolization fever, dysphagia, and transient chest pain which were managed symptomatically. After a median follow-up period of 10.5 months (range 0.5-38 months), no recurrence of hemoptysis was observed in 8 patients who are still alive. In 3 patients hemoptysis recurred and they underwent reembolization after 3, 22, and 25 months, respectively. Three subjects died of respiratory failure within 5 months from BAE. Presently, 50% of patients studied had a > or = 1 year interval free of major hemoptysis after the first BAE. Our experience indicates that massive and/or recurrent hemoptysis in CF patients can be safety and effectively managed by BAE if the procedure is performed by a skilled practitioner. The procedure was well tolerated and resulted in prolonged and satisfactory bleeding control in most patients.

Adolescent↗
PubMed1993

Manganese induces spreading and process outgrowth in rat pheochromocytoma (PC12) cells.

Mn2+ has been shown to promote cell-substrate adhesion and cell spreading in many cell culture systems. In this study, we present data demonstrating that Mn2+ not only promotes spreading, but also induces process outgrowth in rat pheochromocytoma (PC12) cells. In the presence of 1.0 mM MnCl2, cell spreading was apparent by 6 hr, and nearly 50% of the exposed cells extended neurite-like processes. These morphological effects of Mn2+ were both time- and dose-dependent. In the presence of cycloheximide, a protein synthesis inhibitor, both Mn(2+)-induced spreading and neurite outgrowth were prevented, indicating that de novo protein synthesis is required for the effects of Mn2+ to take place. Of the other divalent cations tested, Mg2+, Cd2+, Cu2+, Ni2+, and Zn2+ were ineffective, and only Co2+ partially mimicked the effects of Mn2+. Although Mn(2+)-induced cell adhesion and spreading have been extensively studied, this is the first report that this divalent cation can cause neurite outgrowth. The neurite outgrowth-promoting effects of Mn2+ were distinct from those of nerve growth factor in that the response to Mn2+ was considerably more rapid, but apparently lacked the ability to sustain continuous outgrowth and networking of neurites. Mn2+ also induced the levels of GAP-43 and peripherin, two proteins associated with neuronal differentiation of PC-12 cells. In cells grown in serum-free defined medium, Mn2+ was capable of promoting neurite outgrowth when the cells were plated on surfaces pretreated with normal growth medium, vitronectin, or fibronectin, while it failed to cause these morphological changes in cells plated on untreated or poly-D-lysine-coated substrata. Similarly, Mn2+ also promoted neurite outgrowth from rat sympathetic neurons attached to laminin-treated substrate, but had no effect on neurons maintained on substrate with polylysine only. The pentapeptide Gly-Arg-Gly-Asp-Ser nearly completely prevented the morphological effects of Mn2+ on PC12 cells. These findings are consistent with a hypothesis that Mn(2+)-mediated alteration of an RGD-dependent extracellular matrix-integrin interaction is responsible for the neuritogenic effects.

Amino Acid Sequence↗
PubMed1993

Positron-emission tomographic localization of abnormalities of brain metabolism in patients with minimal hepatic encephalopathy.

Many patients with compensated cirrhosis without overt hepatic encephalopathy have deficits in visual-spatial perception, a condition we call minimal hepatic encephalopathy. Five patients with alcohol-induced cirrhosis and nine control subjects underwent positron-emission tomographic imaging of the brain with 18F-fluorodeoxyglucose. Patients also underwent neuropsychological and clinical chemistry tests. The patients had mild arterial hyperammonemia (62 +/- 13 mumol/L, range = 11 to 35 mumol/L) and other abnormalities typical of patients with cirrhosis. The patients' mean percentile scores on the digit symbol and block design subtests, from the Wechsler Adult Intelligence Scale (revised), and Purdue pegboard test were 11 +/- 7, 24 +/- 7 and 7 +/- 8 (right hand). Tests of vocabulary, memory, and new learning were normal. The technique of statistical parametric mapping was used to identify regions where cerebral 18F-fluorodeoxyglucose uptake and metabolism were abnormal. We noted significant reductions in the cingulate gyrus, a center mediating attention, target analysis and response formulation and significant increases in visual associative regions subserving motion and color perception and object orientation. We suggest that minimal hepatic encephalopathy is due to a deficit in the detection and formulation of responses to visual stimuli, a function of the cingulate, which is a part of the anterior attentional system of the brain. Increases in 18F-fluorodeoxyglucose metabolism may be compensatory. These studies show that brain regions differ in their sensitivity to the agents that cause hepatic encephalopathy and that positron-emission tomography is useful in studying the pathophysiology of this disorder.

Adult↗
PubMed1992

Multiple conductance levels in rat heart inner mitochondrial membranes studied by patch clamping.

The behavior of the mitochondrial inner membrane multiple conductance channel (MCC) which has a peak conductance of 1-1.5 nS has been examined in rat heart mitochondria. MCC can display several unique characteristics: (a) prolonged open and closed times on the order of seconds to minutes, (b) a voltage dependence in which MCC opens (negative potential) or closes (positive potential) generally in steps, (c) a response to inhibitors such as amiodarone in steps corresponding at least approximately to those in (b), (d) a 'free-running mode' in which the current level rapidly fluctuates between a minimum of nine conductance levels but with a preferred occupation of the 0.5-0.7 nS levels, and (e) very large transitions (1-1.5 nS) resolved at 4 kHz bandwidth as single events with variable mean open time.

Animals↗
PubMed1991

Selective effect of inhibitors on inner mitochondrial membrane channels.

The effect of amphiphilic cationic drugs on the channel activity of the mitochondrial inner membrane was examined with patch-clamp techniques. The therapeutic drugs amiodarone, propranolol and quinine reduced the probability of being open for the multiconductance channel (MCC) activity (levels from 30 pS to over 1 nS). While amiodarone decreased the probability of being open for the voltage dependent approximately 100 pS channel, it increased the conductance 42 +/- 20% (mean +/- SD, n = 6) with no significant change in mean open time. Similar results were obtained with propranolol. These data indicate that the approximately 100 pS channel is distinct from MCC activity.

Amiodarone↗
PubMed1991

Calcium modulation of mitochondrial inner membrane channel activity.

Protocols were defined that enable patch-clamp studies of the approximately 107 pS voltage dependent channel and a class of activity we refer to as MCC (multiconductance channel) which is characterized by multiple levels and transitions as high as 1 to 1.5 nS. If free calcium was kept at 10(-7) M or lower during mitochondrial isolation, no activity was observed at low voltage (+/- 60 mV). If free calcium levels were higher, MCC activity was observed in about 96% of the patches. The observation of approximately 107 pS channel was enhanced from 2% to 68% of patches by washing isolated mitoplasts (mitochondria stripped of outer membrane) with EGTA. Increasing matrix calcium from 10(-9) to 10(-5) M decreased the probability of opening for the MCC and approximately 107 pS activities.

Animals↗
PubMed1991

Spontaneously healed vein of Galen aneurysms. Clinical radiological features.

Vein of Galen aneurysms demonstrate a high tendency to thrombose, as extensive thrombophlebitis of the dural sinuses and deep venous system occurs frequently. This may be explained by the frequent detection of venous anomalies and retention of embryonic venous patterns such as the median prosencephalic vein. Twenty-one cases were reviewed (19 from the literature, 2 of our own cases): no typical syndrome for thrombosed aneurysm of the vein of Galen could be found; therefore, a preliminary diagnosis of clotted vein of Galen aneurysm was made in only half the cases. In all the remaining ones, pineal or III ventricle masses were suspected. Nevertheless, crescentic rimlike calcifications in the region of the vein of Galen can be found in 50% of cases. Only in half of the cases did angiography demonstrate the malformation filled by contrast medium, while in the remaining cases not only the aneurysm but also the deep Galenic venous system failed to opacify. Computed tomography and magnetic resonance scans demonstrated masses with high density/intensity values, with varying degrees of calcification. Knowledge of this pathological entity is important in order to avoid unnecessary surgical procedures.

Adolescent↗
PubMed1989

Interventional angiography in neuropediatrics.

Since the introduction of non-invasive imaging techniques (CT, US, MRI), superselective cerebrospinal angiography has been playing a major role as a diagnostic tool as well as a therapeutic procedure prior to surgery or as an alternative. Surgical neuroangiography is now also a well-established therapeutic technique in neuropediatrics. Lesions fed by the external carotid artery and spinal cord lesions are the main indications. The first group consists of maxillofacial vascular malformations, nasopharyngeal angiofibromas, and vascularized tumors of the facioorbital area (hemangiopericytoma, angiosarcoma ...). Spinal lesions for which embolization can be considered are benign tumors of the vertebral column (vertebral hemangioma, aneurysmal bone cyst ...) and vascular malformations intrinsic to the spinal cord. Particles (Ivalon, dura) are the safest embolization materials and have a wide range of possible applications; glues such as IBC have defined but limited indications. Digital subtraction angiography is crucial during the procedure and in determining the overall doses of contrast medium to be administered. Furthermore, decisions can be made more rapidly and precisely, with a definite improvement in the therapeutic results.

Angiography↗
PubMed1989

Serological response to chlamydial infection in sheep, studied by enzyme-linked immunosorbent assay and immunoblotting.

Two enzyme-linked immunosorbent assays (ELISA) using highly purified elementary bodies (EB) of Chlamydia psittaci A/22 strain (ovine) or 6BC strain (psittacine) were set up for the detection of antichlamydial antibodies in sheep. No significant differences were observed between the two ELISAs, whereas these tests proved to be more sensitive than complement fixation test and showed a good correlation (r = 0.75) with immunofluorescence assay. The periodate treatment of chlamydial antigens modified the results of serological responses studied by ELISA, depending on the sera. The average reduction of ELISA values by periodate was 28%, ranging between 5% and 65%. The immunoblot analysis of sheep sera showed high cross reactivity between the polypeptides of A/22 and 6BC strains. However, some differences were observed. The major outer membrane protein (MOMP) of 6BC strain was recognized at different molecular weight position (40,000 kDa) in comparison with the MOMP of A/22 strain (38,000 kDa). In addition, a clear band of 97,000 kDa was detected by all sheep sera tested with A/22 strain. This band was undetectable in the blots performed with 6BC strain.

Animals↗