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Biomedical subjects

G Lorenzi

Publications and source records attributed to G Lorenzi.

34 records · Page 2Linked to original sources
PubMed1980

[Epidemiological evaluation of thromboembolic risk. Critical review of the prospects offered by determination of antithrombin III].

Authors review the epidemiology of deep venous thrombosis and the prothrombotic state in high risk patients; particularly antithrombin III role in blood clotting is considered. A fall in antithrombin III concentration and/or activity can induce hypercoagulability and thrombosis. Moreover authors stress the need to evaluate antithrombin III as anti-Xa activity, to detect high risk patients for deep venous thrombosis.

Antithrombin III↗
PubMed1978

Tissues concentration and excretion of deslanatoside C-3H in newborn and growing rabbits.

Deslanatoside C-3H was injected (i.p. 50 microgram/kg) into rabbits of 1, 4, 10, 20 days and more than 1 year old. The rabbits were sacrificed 2 and 6 h after dosing. Levels in all tissues were higher in newborn rabbits, decreased in the older animals and then in most tissues increased in adults to different degrees, showing the highest values in kidneys. Biliary excretion and above all urinary excretion increased with age. Levels in atria, ventricles, aorta and liver in rabbits 1 and 4 days old were consistently higher at the 6th h than those at the 2nd h, these tissues showing a particularly marked avidity with Deslanatoside C; in the older animals this behaviour was reversed. These data and those of other Authors working on other glycosides (incleding Digoxin) and other species (including newborn children) lead to the conclusion that digitalis glycosides in new born species are excreted at a lower rate and incorporated in the body tissues at a higher rate than in adults. They may also in part explain the large dosages employed in human infants in comparison with adults, as the higher distribtuion volume retains a large amount of the injected glycoside.

Aging↗
PubMedDate not supplied

Nasal mucus clearance in rats: differences with sex and phase of the oestrous cycle.

We studied the changes in airway mucus rheology and clearability, as well as in morphometric indices, between male rats and females in either the oestrous or dioestrous phases of the oestrous cycle. Three-month-old Wistar rats were studied and the phases of the oestrous cycle were determined based on analysis of vaginal smears stained by a modified Shorr's procedure. Nasal mucus samples were analysed by means of magnetic rheometry and determination of in vitro transport rate in the frog palate preparation. In situ clearance on the exposed nasal septum was also determined. The mucociliary velocity in situ was significantly affected by both sex and the oestrous cycle phase. In female rats, dioestrous phase clearance was significantly slower than the oestrous phase one. Clearance in male rats was faster than that of both the phases studied in females. Mucus rigidity of females in the oestrous phase was more rigid than that of females in the dioestrous phase and that of males. Mucus viscosity/elasticity ratio for deformations performed at high frequencies was greater for females in comparison with males. Cough clearability computed on the basis of rheological parameters was predicted to be more favourable in females. There were no significant differences between the three groups in mucociliary clearance in vitro. Morphometric studies of the nasal epithelium showed that epithelial and glandular volumes did not exhibit sex- or oestrous-phase-related differences, but the amount of epithelial acidic glycoproteins was lower in females in the oestrous phase in comparison with males and those in the dioestrous phase, the same trend being observed in the glands of the lamina propria.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Correlation between rheologic properties and in vitro ciliary transport of rat nasal mucus.

The relationship between mucus rheologic variables and in vitro ciliary transport was investigated in mucus samples collected from the upper airways of 30 Wistar rats. In vitro mucus transportability was determined by means of the frog palate preparation. Rheologic evaluation was done by measuring the rigidity modulus (log G*, representing the vectorial sum of viscosity and elasticity) and the loss tangent (tan delta, i.e. the ratio between viscosity and elasticity) at 1 and 100 radian/s using a magnetic microrheometer. The correlation between the rheologic variables and in vitro mucus transportability was made by stepwise multiple linear regression analysis, with frog palate transport rate considered as the dependent variable. A significant relationship was obtained between the rheologic parameters (log G* and tan delta) measured at 1 radian/s and the frog palate transport ratio. The relative speed of mucus samples was related to rheology according to the following relationship: rat/frog speed ratio = 1.666-0.434 log G*-0.331 tan delta, for G* and delta determined at 1 radian/s (multiple r = 0.666, p < 0.001). Transport rates predicted from the above formula gave a satisfactory fit to those observed in a second set of 30 rats. The present results indicate that the overall mucus impedance, as well as the ratio between viscosity and elasticity, are important in determining the efficiency of clearance. In addition, it was shown that measurements performed by applying relatively low frequency deformations are preferable for predicting ciliary transport.

Animals↗
PubMedDate not supplied

PTA and laser assisted PTA combined with simultaneous surgical revascularization.

In this study we investigated the efficacy of percutaneous transluminal angioplasty (PTA) and laser percutaneous transluminal angioplasty (LPTA) as an adjunct to surgery in patients with peripheral vascular disease. We report 84 cases of the simultaneous association of direct arterial surgery and angioradiological procedures to treat 82 patients with arterial occlusive disease of the lower limbs. Sixty-five patients (79.2%) were affected by severe claudication and 14 (19.6%) presented with rest pain or gangrene. One patient (1.2%) had signs of acute ischemia. PTA or LPTA were utilized as an inflow procedure in 41 cases (48.8%), as an outflow procedure in 24 (28.6%) and in 19 cases (22.6%) to recanalize an arterial occlusion in the contralateral limb opposite to surgical interventions. Immediate postoperative patency was achieved in 79 cases (94.0%), while in 5 cases (6.0%) it was impossible to perform a satisfactory balloon dilatation. The complication rate was 16.6%: 10 perioperative thromboses, 1 plaque dissection, 1 peripheral embolus, 1 haemorrhage and 1 femoral nerve lesion. No perioperative mortality occurred in this group of patients. Long term patency, analyzed with the life-table method (mean follow-up: 28 months) was respectively 78.0%, 76.3% and 78.9% at 5 years. These data indicate that the combined revascularization technique should always be recommended in properly selected patients because it is less invasive, the surgical risk and operative time are reduced and associated with early and long term cumulative patency rates comparable to those of extensive surgery.

Adult↗
PubMedDate not supplied

Femoral noninfected anastomotic aneurysms. A report of 56 cases.

Fifty-six femoral non infected anastomotic false aneurysms (FAAs) were observed in 49 patients admitted to the Institute of Vascular Surgery, University of Milan, from 1975 to 1988; in 6 patients they were bilateral. These aneurysms developed after primary revascularization procedures at a mean interval of 66 months (range 12 to 156 months); one recurred after reparative surgery. Forty-four FAAs (78.6%) were asymptomatic, whereas 3 (5.3%) were complicated by acute expansion and 9 (16.1%) by thrombosis. Host vessel degeneration was the cause of aneurysm formation in most cases. A history of hypertension was present in 30% of the patients. All anastomotic aneurysms were operated upon except for one small aneurysm that was asymptomatic. In 5 patients aneurysm resection was carried out on both sides. The surgical technique was endoaneurysmectomy in all the cases with insertion of an interposition graft in 48 cases, a fabric patch in 2 cases and prosthesis re-anastomosis in 5 cases. One case of peripheral embolization occurring in the early postoperative period was successfully treated and there was no operative mortality. In our opinion elective repair of these aneurysms should be recommended whenever possible because of their propensity to develop serious complications and the operative morbidity is low.

Aged↗
PubMedDate not supplied

Thrombectomy for late graft limb occlusion: our experience in 182 consecutive cases.

Late occlusion of an aortofemoral bypass graft is usually caused by fibrointimal hyperplasia or progressive atherosclerosis. Several surgical approaches have been advocated in order to minimize the operative risk, to correct the impaired inflow and to provide a satisfactory outflow. In the last 16 years, in the Institute of Vascular Surgery and Angiology of the University of Milan, we have operated upon 182 consecutive thrombosed grafts. Inflow was restored by performing a graft limb thrombectomy using a Fogarty balloon catheter and simultaneously employing an endarterectomy ring stripper to dislodge tenaciously adherent fibrinous material and thrombotic plug. As the superficial femoral artery was generally occluded, usually a good outflow was achieved by profundaplasty in 101 cases (55.5%) or direct bypass (interposition graft), to a more distal segment of the profunda femoris artery in 55 cases (30.2%). Concomitant popliteal or tibial revascularization was done in the remaining 26 cases (14.3%) when pre-operative or intra-operative findings suggested an inadequate collateral network through the profunda femoris artery. Early re-occlusion, which occurred in 14 cases (7.6%), generally due to insufficient outflow, was corrected by additional intervention in 7 cases (3.8%), while 7 legs were amputated for extensive atherosclerotic disease. Six patients died giving a mortality rate of 3.3%. This low rate in a high risk population is probably related to our policy of operating under loco-regional anaesthesia. Long term results, with a patency rate of 62.0% at 3 years and 60.2% at 5 years (life table method), prove that this operation is a durable procedure for correction of graft limb thrombosis.

Aorta, Abdominal↗
PubMedDate not supplied

Treatment of peripheral congenital arterio-venous fistulas.

The authors describe their experience in the treatment of peripheral congenital A-V fistulas in 64 cases. Different surgical procedures (skeletation, "en bloc resection") have been performed in 19 patients, embolization in 15 patients. The need for a more radical and definitive procedure has induced the authors, in a recent series of 6 patients, to associate embolization and surgical therapy in the same operative session. The results are encouraging. The technique is reported.

Adult↗
PubMedDate not supplied

Rupture of gastroduodenal artery aneurysm into the portal vein.

Aneurysms of the gastroduodenal artery are very rarely observed. Rupture occurs in about 60% of cases and is usually associated with gastroduodenal bleeding. A case of rupture into the portal vein and secondary portal hypertension is presented. The combined use of computed tomography (CT scan) and selective visceral angiography was very useful for the diagnosis.

Aged↗
PubMedDate not supplied

[Indications and limitations of endovascular surgery in carotid revascularization].

PURPOSE: Today percutaneous transluminal angioplasty is seldom utilized to treat carotid artery stenosis and the indications and results of this procedure are discordant between the few authors that do it. This leads to caution in selecting PTA as the first choice. Analysing the literature and their own experience, authors describe optimal indications and technique for this procedure. METHODS: Eight patients with stenosis of the common carotid artery and five patients with stenosis of the internal carotid artery were treated with PTA. In the first group five cases were performed in association with a surgical distal revascularization, to obtain a good run-in. In six cases symptomatic restenosis due to intimal hyperplasia were treated. The two remaining cases were relative to complex clinical situations and high operative risk. RESULTS: In eleven patients out of thirteen a good clinical and hemodynamic result was obtained; in one case the carotid artery occluded and in another case a new restenosis occurred. DISCUSSION: PTA has some advantages: low operative trauma, cerebral ischemia short time, possibility to treat inaccessible or hardly accessible lesions. The eventuality of complications is high and for this reason the procedure must be utilised only in selected cases, with prudence and with a team well trained in peripheral angioplasty. CONCLUSION: PTA for carotid artery stenosis today is still an experimental procedure; its value in comparison with carotid endarterectomy has to be proven with well designed clinical randomized trials.

Angioplasty, Balloon↗