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Biomedical subjects

L Pedrini

Publications and source records attributed to L Pedrini.

At least 19 recordsLinked to original sources
PubMed2002

The effect of transient intestinal ischemia on inflammatory parameters.

BACKGROUND AND AIMS: To determine the early biological changes occurring in intestinal ischemia in vivo. PATIENTS AND METHODS: We studied the effects of acute transient intestinal ischemia in 15 patients undergoing elective open surgery for the treatment of abdominal subrenal aortic aneurysm induced by clamping of the aorta at subrenal level and above the branching of the inferior mesenteric artery. Blocking the blood flow results in hypoperfusion of the inferior mesenteric artery and then to rectal mucosal ischemia. RESULTS: With the introduction of a mucosal ischemic period the basal intestinal mucosal pH decreased during ischemia, and showed a rapid increase during reperfusion to the level preceding ischemia. Parameters were evaluated in blood taken from inferior mesenteric vein. A rectal dialysis was put into the rectum to evaluate eicosanoid concentrations in rectal fluid collected before and during clamping and after declamping. Significant enhancement in plasma level of xanthine, a marker for tissue damage, was observed during reperfusion. Interleukin-6 levels were significantly elevated from 11.28+/-3.4 pg/ml (preischemic) to 109+/-85.9 pg/ml (ischemic) and to 189.33+/-120.24 pg/ml (reperfusion); and tromboxane B(2) levels from 141.57+/-51.20 pg/ml preoperation to 473.01+/-319.01 pg/ml during the surgical procedure. CONCLUSION: These observations indicate that even transient ischemia modifies the inflammatory pattern.

Aged↗
PubMed2001

Evaluation of thrombogenicity of fluoropassivated polyester patches following carotid endarterectomy.

The use of a patch after carotid endarterectomy (CE) is recommended to reduce the incidence of restenosis. Most studies on this subject report the implantation of saphenous vein or PTFE patches, because polyester has always been considered to be a thrombogenic material. The purpose of this study was to evaluate the thrombogenicity of a knitted polyester patch passivated by fluoropolymer surface treatment (FPD patch), which experimental studies have demonstrated to be less thrombogenic than other materials. This prospective, randomized study was performed in 22 patients who underwent CE. In 11 patients the arteriotomy was sutured directly, while in the other 11 an FPD patch was applied. Patients' 111in-oxine labeled platelets were reinjected on the first postoperative day, and scintigraphies were performed after 4, 24, and 48 hr, respectively. The study confirmed that an FPD patch is no more thrombogenic than a simple carotid endarterectomy. The application of the patch, therefore, can be recommended to reduce restenosis without any adjunctive thromboembolic risk.

Aged↗
PubMed2000

Effect of high-flux dialysis on the anaemia of haemodialysis patients.

BACKGROUND: Anaemia is one of the major clinical characteristics of patients with chronic renal failure, and has a considerable effect on morbidity and mortality. Adequate dialysis is of paramount importance in correcting anaemia by removing small and medium-sized molecules, which may inhibit erythropoiesis. However, high-molecular-weight inhibitors cleared only by means of highly porous membranes have also been found in uraemic serum and it has been claimed from uncontrolled studies that high-flux dialysis could improve anaemia in haemodialysis patients. METHODS: We therefore planned this multicentre randomized controlled trial with the aim of testing whether the use of a large-pore biocompatible membrane for a fixed 12-week follow-up improves anaemia in haemodialysis patients in comparison with the use of a conventional cellulose membrane. Eighty-four (5.3%) of a total of 1576 adult haemodialysed patients attending 13 Dialysis Units fulfilled the entry criteria and were randomly assigned to the experimental treatment (42 patients) or conventional treatment (42 patients). RESULTS: Haemoglobin levels increased non-significantly from 9.5+/-0.8 to 9.8+/-1.3 g/dl (dP=0. 069) in the population as a whole, with no significant difference between the two groups (P:=0.485). Erythropoietin therapy was given to 32/39 patients (82%) in the conventional group, and 26/35 (74%) in the experimental group (P:=0.783) with subcutaneous administration to 26/32 patients in conventional and to 23/26 patients in experimental group, P:=0.495. Dialysis dose (Kt/V) remained constant in both groups (from 1.30+/-0.17 to 1.33+/-0.20 in the conventional group and from 1.28+/-0.26 to 1.26+/-0.21 in the experimental group, P:=0.242). Median pre- and post-dialysis beta(2)-microglobulin levels remained constant in the conventional group (31.9 and 34.1 mg/dl at baseline) and decreased in the experimental group (pre-dialysis values from 31.1 to 24.7 mg/dl, P:=0.004 and post-dialysis values from 24.8 to 20.8 mg/dl, P:=0.002). Median erythropoietin doses were not different at baseline (70 IU/kg/week in conventional treatment and 90 IU/kg/week in experimental treatment, P:=0.628) and remained constant during follow-up (from 70 to 69 IU/kg/week in the conventional group and from 90 to 91 IU/kg/week in the experimental group, P:=0.410). Median erythropoietin plasma levels were in the normal range and remained constant (from 12.1 to 12.9 mU/ml in the conventional group and from 13.2 to 14.0 mU/ml in the experimental group, P:=0.550). CONCLUSIONS: This study showed no difference in haemoglobin level increase between patients treated for 3 months with a high-flux biocompatible membrane in comparison with those treated with a standard membrane. When patients are highly selected, adequately dialysed, and have no iron or vitamin depletion, the effect of a high-flux membrane is much less than might be expected from the results of uncontrolled studies.

Aged↗
PubMed2000

Superior vena cava thrombosis secondary to thoracic outlet syndrome. Case report.

A case of superior vena cava thrombosis secondary to the thoracic outlet syndrome is reported. The diagnosis was revealed by CT-scan and confirmed by phlebography performed to insert a catheter for intrathrombotic infusion of urokinase. The thrombolytic treatment was followed by complete clot lysis. A hyperabduction manoeuvre confirmed costoclavicular compression as the cause of the subclavian-axillary vein thrombosis for which the patient underwent first rib resection. Axillary-subclavian vein thrombosis (or Paget-von Schroetter syndrome) is a relatively frequent complication of the thoracic outlet syndrome often treated with anticoagulants on the basis of a duplex examination. Involvement of the superior vena cava is not readily detected by duplex ultrasound so a partial thrombosis, with a possible fatal outcome could remain undiagnosed. Full investigation by phlebography or CT-scan is therefore recommended. In addition, transcatheter thrombolytic therapy has a lower incidence of follow-up complications than heparin.

Humans↗
PubMed1998

A randomized study comparing methylprednisolone plus chlorambucil versus methylprednisolone plus cyclophosphamide in idiopathic membranous nephropathy.

To assess whether chlorambucil or cyclophosphamide may have a better therapeutic index in patients with idiopathic membranous nephropathy, we compared two regimens based on a 6-mo treatment, alternating every other month methylprednisolone with chlorambucil or methylprednisolone with cyclophosphamide. Patients with biopsy-proven membranous nephropathy and with a nephrotic syndrome were randomized to be given methylprednisolone (1 g intravenously for 3 consecutive days followed by oral methylprednisolone, 0.4 mg/kg per d for 27 d) alternated every other month either with chlorambucil (0.2 mg/kg per d for 30 d) or cyclophosphamide (2.5 mg/kg per d for 30 d). The whole treatment lasted 6 mo; 3 mo with corticosteroids and 3 mo with one cytotoxic drug. Among 87 patients followed for at least 1 yr, 36 of 44 (82%; 95% confidence interval [CI], 67.3 to 91.8%) assigned to methylprednisolone and chlorambucil entered complete or partial remission of the nephrotic syndrome, versus 40 of 43 (93%; 95% CI, 80.9 to 98.5%) assigned to methylprednisolone and cyclophosphamide (P = 0.116). Of patients who attained remission of the nephrotic syndrome, 11 of 36 in the chlorambucil group (30.5%) and 10 of 40 in the cyclophosphamide group (25%) had a relapse of the nephrotic syndrome between 6 and 30 mo. The reciprocal of plasma creatinine improved in the cohort groups followed for 1 yr for both treatment groups (P < 0.01) and remained unchanged when compared with basal values in the cohort groups followed for 2 and 3 yr. Six patients in the chlorambucil group and two in the cyclophosphamide group did not complete the treatment because of side effects. Four patients in the chlorambucil group but none in the cyclophosphamide group suffered from herpes zoster. One patient per group developed cancer. It is concluded that in nephrotic patients with idiopathic membranous nephropathy both treatments may be effective in favoring remission and in preserving renal function for at least 3 yr.

Adolescent↗
PubMed1998

Calcium-PTH relationship in dialysis patients: the pitfalls of using a constant dialysate calcium concentration during the dynamic tests.

The calcium-PTH relationship in uremic patients has been often studied during dialysis sessions with high or low dialysate calcium concentration (CaD). This method has been used because it is less complex and invasive than i.v. infusion of calcium salts and calcium chelating agents. However, the constancy of CaD during the tests does not allow for the control of the serum calcium profile and, given that the blood calcium concentration is only one factor of a more complex calcium-related mechanism of the PTH release, the calcium-PTH curve may become dependent on the unpredictable rate at which the ionized calcium changes. Dynamic testing of the parathyroid gland was performed in 9 dialysis patients comparing constant CaD of 1.0 and 2.0 mmol/l (A) with a linear change in CaD (B). The rate of serum calcium change remained constant over time only in experiment B. The total decrease in calcemia (0-0.38 +/- 0.03 vs -0.14 +/- 0.1 mmol/l) and PTHmax (748.25 +/- 124.76 vs 374.89 +/- 53.03 pg/ml) were significantly higher in B, whereas the total increase in calcemia (+0.26 +/- 0.03 vs +0.28 +/- 0.02 mmol/l) and the minimum value of PTH (59.15 +/- 9.53 vs 55.64 +/- 9.08 pg/ml) were similar in both experiments. The calcium-PTH curves were clearly different in A and B. The setpoint and the slope were significantly higher in A (1.196 +/- 0.01 vs 1.142 +/- 0.02 mmol/l; 840.54 +/- 96.85 vs 542.43 +/- 112.26%/mmol). For similar serum calcium values (1.084 +/- 0.01 vs 1.059 +/- 0.02 in the stimulation test and 1.325 +/- 0.02 vs 1.336 +/- 0.02 mmol/l in the inhibition test) the PTH secretion was significantly different (335.86 +/- 44.36 vs 647.65 +/- 104.09 in the stimulation test and 76.35 +/- 12.57 vs 105.03 +/- 20.59 pg/ml in the inhibition test). In conclusion, the way of inducing serum calcium change affected the calcium-PTH curve and the value of the set point and the slope was a function of the way in which the blood calcium changes were achieved. The modulated CaD dialysis was shown to be a more correct method of studying the calcium-PTH relationship in dialysis patients, as well as an alternative to the more complex and invasive infusional methodology.

Calcium↗
PubMed1998

Intraoperative assessment of cerebral ischaemia during carotid surgery.

BACKGROUND: This study aimed to evaluate the reliability of somatosensory evoked potentials (SEPs) in identifying clamping ischaemia during carotid surgery under general anaesthesia. METHODS: We reviewed the records of 196 consecutive carotid endarterectomies (CEA) performed under general anaesthesia, out of 1550 patients operated on between 1975 and 1993. SEPs were monitored after contralateral median nerve stimulation at the wrist in all patients. Moreover they received an intravenous bolus of 2500 IU of heparin and the stump pressure was measured. A completion angiography was performed in all patients. An intraluminal shunt was inserted when the amplitude of the N20-P25 SEPs complex decreased by more than 50% of pre-clamping value (pathologic SEPs) or when a preoperative CT-scan showed an ischaemic area in the contralateral hemisphere. In some patients the shunt was not inserted because of technical difficulties or because the pathological SEP complex decrease developed when the suture of the arteriotomy was almost complete. RESULTS AND CONCLUSIONS: As the preclamping amplitude (Ab) of N20-P25 was extremely variable, ranging from 0.9 and 7.5 microV, we adopted the ratio: deltaA=(At-Ab)/Ab (At=amplitude measured during clamping every 2 min at time t). Mean decrease of deltaA measured in the whole group ranged between 15% and 20%, but mean deltaA values in patients with pathological SEPs were around 60%. Even patients with positive CT-scans or with a back-pressure lower than 50 mmHg developed a mean deltaA decrease of about 20%. A pathological SEP was present in 50 patients, but developed in only 12 during the clamping trial. An intraluminal shunt was inserted in 22 cases; the other patients received pharmacological treatment with anaesthetic or vasoactive drugs. Among the patients with pathological SEPs, 3 presented postoperative symptoms related to carotid cross-clamping; only 1 of these was shunted but without SEPs normalisation. No patients with normal SEPs developed a postoperative neurological deficit, giving a reliability of 86.7%, a sensitivity of 100% and a specificity of 86.5%.

Aged↗
PubMed1996

Extracranial internal carotid artery aneurysms: results of a surgical series with long-term follow-up.

PURPOSE: The purpose of this study was to analyze mode of presentation, surgical treatment, and early and long-term results of a series of extracranial internal carotid artery aneurysms (EICAA). METHODS: A retrospective analysis was performed on all cases treated for EICAA in a single institution from March 1974 to March 1995. Patient follow-up was obtained by a surveillance protocol, with duplex scanning performed 3 months after surgery and yearly thereafter. RESULTS: Twenty-four EICAA in 20 patients were treated over a 21-year period. The cause was fibromuscular dysplasia in 12 cases (50%), nonspecific "atherosclerosis" in nine (37.5%), previous carotid artery surgery in two (8.3%), and trauma in one case (4.1%). Neurologic symptoms were present in a total of nine cases (37.5%) and were hemispheric in seven (29.1%) and nonhemispheric in two (8.3%). Operative techniques were performed with patients receiving general anesthetic and included aneurysm excision with internal carotid artery reanastomosis (8 cases [33.3%]) or reimplantation onto the external carotid artery (1 case [4.1%]); interposition graft (10 cases [41.6%]), 7 veins, 3 polytetrafluoroethylene) or simple aneurysmectomy and closure of the wall defect either with (3 cases [12.5%]) or without (2 cases [8.3%]) a patch. Elective surgery was performed in 22 cases, with a 0% mortality rate and 4.5% stroke rate. Emergency operations were performed in two cases of ruptured aneurysms (one spontaneous and one iatrogenic); one patient (50%) died. Cranial nerve morbidity occurred in five cases (20.8%). Mean follow-up was 96.7 +/- 88.15 months (range 4 to 240 months) and included 2 of 7 (28%) complications in saphenous vein grafts, 1 (4.1%) late transient ischemic attack, and a recurrent aneurysm after 19 years. CONCLUSIONS: Symptoms and potential complications caused by EICAA suggest a broad surgical indication. EICAA can be treated safely because of the good early and long-term results.

Aged↗
PubMed1996

[Non-cardiac causes of acute ischemia in the arms].

Among a series of 286 cases of acute ischemia of the upper limb, we analyzed the files of 176 patients (61.5%) with noncardiac ischemia in order to identify the causes and treatment. Trauma was the most frequent cause (126 cases) including trauma of the forearm especially due to stab wounds. Lesions with a subclavian-axillary localization were predominantly due to tear wounds or blunt trauma. We analyzed two groups among the trauma cases: iatrogenic lesions (9 cases) usually resulted from orthopedic surgery (5 cases) or vascular catheterization (3 cases) as well as near-total limb amputations (13) cases. Thrombosis of the subclavian artery occurred in 33 patients; 9 had acute ischemia including 3 due to a cervical rib and 6 due to compression by the rib and the clavicle. Only 4 of these 33 patients suffered ischemia of the hand due to embolization. Acute ischemia was caused by arteriopathy of the hand in 8 patients including 2 volley ball players, 1 baseball player and 3 subjects with occupational microtrauma and 1 with thrombosis of the palmar arch. Finally 1 patient had thrombosis after intravenous drug injection. These files demonstrated the variety of non-cardiac causes of acute ischemia of the upper limb. During the acute phase, we propose locoregional thrombolysis in case of thrombosis and embolectomy for emboli followed by treatment of the casual lesion. An arteriography is essential for correct diagnosis and should include the subclavian artery in the hyperabduction position and the hand. Duplex scanning of the subclavian artery is indicated in case of ischemia of the hand using the Adson, McGowan and Wright maneuvers in order to guide the radiologist for invasive radiography before initiating appropriate treatment.

Acute Disease↗
PubMed1996

Ischemia: reperfusion syndrome of the lower limbs.

The ischemia-reperfusion syndrome, first described by Haimovici in 1960, is a severe complication following surgery for acute ischemia. We evaluated the incidence of this complication in 264 patients operated on between 1972 and 1981 (1st group) and compared it with another of 392 patients operated on between 1982 and 1991 (2nd group), our aim being to assess the effects of pharmacological prophyiaxis based on preoperative overhydration followed by an intra-arterial bolus of 250 ml 14/1000 HCO3-, containing 1 g dexamethasone and 2500 I.U. sodium heparin, injected into the femoral artery before suturing the arteriotomy. This regimen was based on the measurement of myoglobin and glutathione levels respectively carried out in two subgroups of 25 patients. The results of experimental ischemia-reperfusion syndromes induced in animal using radical scavengers and membrane-protective compounds were also taken into consideration. Following experimental research on sheep, 5 patients in the second group with very severe ischemia due to aortic occlusion received local dialysis in the extracorporeal circulation using hemodialysis or hemofiltration techniques. Mortality was 6.3% in the first group and 5.4% in the second, while the amputation rate was 3% and 1.8% respectively. The overall incidence of the reperfusion syndrome was 3% in the 1st period and 1.8% in the second. Our findings confirm the protective effect of hyper-hydration, radical scavengers and dexamethasone in the ischemia reperfusion syndrome, and indicate that local hemodialysis is a useful adjunct in very severe ischemia.

Aged↗
PubMed1995

[Problems of indications for the treatment of aneurysm of the visceral arteries].

The authors report the clinical history and the treatment of 5 patients with visceral artery aneurysms. The celiac trunk, the common hepatic artery, the inferior pancreaticoduodenal artery and the splenic artery (in 2 different patients) were affected by the aneurysmal disease. Various techniques have been employed in the successful treatment of these patients: radiological embolization of the celiac trunk aneurysms, Dacron graft reconstruction of the common hepatic artery aneurysm, endosaccular ligature and PTFE patching of the inferior pancreatico-duodenal artery aneurysm, endosaccular ligature in one of the two splenic artery aneurysm and simple ligature and splenectomy in the remainder splenic artery aneurysm. Early diagnosis is important in these lesions, because of the trend toward rupture and subsequent high mortality rate. Ultrasonography (US), Computed Tomography (CT) and Magnetic Resonance (MR) are very helpful as diagnostic tools, however angiography represents the method of choice since it could be the first step of the embolization treatment. Furthermore angiography is useful for detection of associated visceral lesions and for the study of collateral blood supply. Treatment choice depends on visceral artery aneurysms localization, the presence of associate lesions and the possible general contraindications. In the latter case, radiological embolization could be the first-choice treatment.

Aged↗
PubMed1995

Prescription and surveillance of the acetate-free biofiltration sessions: the bicarbonate cycle.

A computerized system, structured by 4 different models concerning urea depuration, and bicarbonate and sodium handling in acetate-free hemodiafiltration has been conceived for integrated use covering each step of the therapeutic cycle, from a) the prescription of the session to b) its delivery, up to c) the dose-response analysis: the system, now fully developed for the bicarbonate cycle, covers both working areas; the medical one, with a program implemented on a Personal Computer, called Skipper which deals with steps a) and c), and the nursing area, with a program built into the dialytic equipment software. The Skipper program supports the prescription step (a) testing the session schedule by bicarbonate, sodium and urea kinetics. The dialytic equipment, (step(b)) using a different program, on the basis of the scheduled parameters memorizes the end-session plasma bicarbonate level and reacts to any modifications of the parameters regarding blood flow and fluid reinfusion flow suggesting opposite changes in order to reach the scheduled results. Finally (step (c)), the Skipper system statistically evaluates the observed end session bicarbonate plasma level with an expected value with upper and lower confidence bounds obtained by a multiple regression analysis performed on a large population of patients.

Acetates↗