Biomedical subjects

G Galletti

Publications and source records attributed to G Galletti.

At least 19 recordsLinked to original sources

PubMed2001

Fibrin sealant coated stents compared with non-coated stents in a porcine carotid artery model. Preliminary study report.

BACKGROUND: Balloon expandable metal stents (BEMS) are used to treat restenosis following percutaneous transluminal angioplasty (PTA) and as primary treatment. Intimal proliferation (IP) and resultant restenosis occurs in 25-50% of patients despite all preventive measures. OBJECTIVE: to test the intra-arterial response to the insertion of a fibrin sealant (FS) coated BEMS vs an uncoated BEMS by measuring endothelization and IP. HYPOTHESIS: that a BEMS coated with FS will lead to rapid endothelization and prevent or reduce IP. RATIONALE: FS consists of fibrinogen and thrombin. Thrombin affects endothelial cell proliferation and reduces smooth muscle proliferation, the forerunner of IP and restenosis. Normal endothelium also releases substances that promote vascular relaxation and normal smooth muscle tone regulation. METHODS: Thirty-40 kg pigs (EA), Palmaz-Shatz BEMS (Cordis), FS Tissucol (Baxter Immuno). Stents were uniformly coated with FS in a special mold. Both coated and uncoated stents were mounted on balloon catheters and deployed caudad in the carotid arteries via an arteriotomy. Angiograms were obtained postdeployment. All specimens were examined grossly, photographed then fixed for histology and in some cases, scanning electron microscopy (SEM). RESULTS: Fifteen animals form this preliminary report. Sacrifice at five days as per original protocol showed insufficient stent incorporation. Thereafter 1/2 of the animals were sacrificed at 15 days and 1/2 at 30 days. PATENCY: coated stents: 6 patent, 9 thrombosed. UNCOATED: 7 patent, 8 thrombosed. Of five EA given postoperatively low molecular weight heparin (LMWH) 4 animals had patent stents 80%. HISTOLOGY: varying degrees of IP were seen in all specimens. In general the coated stents showed a greater degree than the uncoated. STENOSIS: presacrifice angiography revealed that where the stents were patent no stenosis was present, in fact, some demonstrated mild dilatation. This was particularly the case with the coated stents. CONCLUSIONS: Coating stents with FS is not detrimental. IP in these EA at 30 days did not produce stenosis. Postoperative LMWH appears helpful in maintaining patency in a thrombogenic experimental animal. Further study maintaining EA for 6-12 months should resolve whether the IP seen had achieved its maximum expression or would progress and produce stenosis.

Angioplasty, Balloon↗

PubMed2000

Mass spectral fragmentations of cholesterol acetate oxidation products.

In this work, electron-impact mass spectroscopy (EI-MS) was employed on a wide range of sterol compounds in order to study their behaviour with regard to their functional groups. In particular, some specific mechanisms of fragmentation occurring in these substrates (i.e. retro-Diels-Alder reaction, neutral molecules eliminations, specific hydrogen migrations) were investigated. Loss of the alkyl side chain and of the D ring were observed in all cases. Finally, a classification of sterols on the basis of characteristic mass spectral fragments is suggested, and further applications to substrates with functional groups on positions other than the A and B rings is proposed.

Animals↗

PubMed2000

Determination of polycyclic aromatic hydrocarbons in sediment using solid-phase microextraction with gas chromatography-mass spectrometry.

Manual solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) is applied for the determination of polycyclic aromatic hydrocarbons (PAHs) from natural matrix through a distilled water medium. Seven of the 16 PAH standards (naphthalene, acenaphthene, fluorene, anthracene, fluoranthene, pyrene, benzo[a]anthracene) are spiked on a marine muddy sediment. The samples, containing PAHs in the range of 10-20 ppm, are then aged at room temperature more than 10 days before analysis. The influence of the matrix, SPME adsorption time, pH, salt content, and SPME adsorption temperature are investigated. The reproducibility of the technique is less than 13% (RDS) for the first 6 considered PAHs and 28% (RDS) for benzo(a)anthracene with a fiber containing a 100-micron poly dimethylsiloxane coating. Linearity extended in the range of 5-50 picograms for PAHs direct injection, 5-70 picograms for PAHs in water, and 1-170 picograms for PAHs in sediment. The detection limit is estimated less than 1 microgram/kg of dry sample for the first 6 considered PAHs in sediment and 1.5 micrograms/kg of dry sample for benzo(a)anthracene using the selected ion monitoring mode in GC-MS. The recoveries of the considered PAHs are evaluated.

Adsorption↗

PubMed2000

[Experimental results of the use of hyaluronic acid based materials (CV Seprafilm and CV Sepracoat) in postoperative pericardial adhesions].

Repeat cardiac surgical procedures are associated with increased technical difficulty and risk related to the presence of dense adhesions between the heart and the surrounding tissues. We examined the efficacy of a bioabsorbable membrane containing hyaluronic acid in the prevention of pericardial adhesions in 23 rabbits. After thoracotomy and pericardiotomy the animals were divided in three groups: Group 1 (9 animals) in which the epicardial surfaces were covered by Seprafilm membrane, Group 2 (9 animals) treated with both Seprafilm membrane and Sepracoat solution, and Group 3 (5 animals) as controls. The animals were reexplored at 10, 30 and 60 days: no intrapericardial adhesions were found in all the animals of Group 2. In 4 animals (44%) of Group 1 localized post-operative adhesions were detected, in absence of epicardial hyperplasia; in contrast, dense and diffuse adhesions were present in all the control animals. The use of the bioabsorbable membrane Seprafilm significantly reduces adhesion formation even if better results are possible with the previous intrapericardial administration of Sepracoat solution. Application of these biocompatible products could reduce the technical difficulty and risk of repeat surgical procedures.

Animals↗

PubMed1998

Combined laparoendoscopic colon resection and anastomosis using the "no touch technique" and fibrin glue. An experimental study.

BACKGROUND: Laparoscopic colon anastomosis are technically demanding. A new technique for colon resection and anastomosis using a combined laparoendoscopic approach is presented. METHODS: In 10 pigs, pneumoperitoneum was induced and 5 trocars were placed. A sigmoid segment was isolated; a vein stripper was inserted from the anus, and the head was secured with a tie; the segment was intussuscepted pulling the stripper out; 4 seromuscular sutures were placed at the anastomotic site and fibrin glue was spread all around; an electrical wire loop, introduced via a colonoscope, was used to resect the intussuscepted segment that was removed from the anus. RESULTS: All animals but one survived until sacrifice at 30, 60, 90, and 120 days. Macroscopically, the anastomosis appeared well healed; microscopically, after 90 days, there was a complete restitutio ad integrum of the intestinal wall. CONCLUSIONS: This technique is feasible and quick; it could be used clinically in small tumors not removable endoscopically.

Anal Canal↗

PubMed1994

Hepatic uptake and intestinal absorption of bile acids in the rabbit.

The existence of transporters for bile acids (BA) in liver and intestine has been well documented, but information is still needed as to their respective transport capacity. In the present investigation, we compared the hepatic and intestinal transport rates for BA, using perfused livers and intestines. The livers and intestines were separately perfused and dose-response curves (0.25-10 mM) for tauroursodeoxycholate, taurocholate and taurodeoxycholate were obtained. The intestinal and mesenteric concentration and bile acid pattern were also evaluated in six non-fasting rabbits. Taurocholic, tauroursodeoxycholic and taurodeoxycholic acid ileal absorption showed saturation kinetics in the intestine as in the liver; the maximal uptake velocity for each bile acid in the liver was tenfold higher than the respective maximal transport velocity in the intestine; the Km values obtained in the liver were of the same order of magnitude, i.e. in the millimolar range. Taurocholic, tauroursodeoxycholic and taurodeoxycholic acid transport differences in the liver paralleled those in the intestine. Although the intestine was not homogeneously filled, the bile acid concentration in the ileal content fell into the range of the Km for the three studied bile acids, while the portal blood total bile acid concentration was inferior to the observed Kms of liver uptake. Therefore, both the hepatic and intestinal systems do not operate at their maximal transport rates at the prevailing concentrations in portal blood and luminal content, and the hepatic transport occurs at its highest efficiency (below the Km values) in physiological conditions.

Animals↗

PubMed1993

The effects of heparin and dietary fish oil on embolic events and the microcirculation downstream from a small-artery repair.

In recent studies we demonstrated that platelet emboli induced by arterial injury impair the microcirculation. The present study was performed to determine if heparin or dietary cod liver oil reduces the incidence of emboli following the same arterial injury and, in turn, whether these agents prevent the associated decrease in microcirculatory blood flow. The cremaster muscle of 29 male Sprague-Dawley rats was isolated on a single neurovascular bundle consisting of the iliac artery and vein and the genitofemoral nerve. Emboli were generated by a thrombogenic injury of the iliac artery, and their number and their subsequent effect on capillary perfusion in the downstream microcirculation were measured. Nine animals received heparin (10-unit IV bolus plus 10 units/hour IV infusion), 10 were fed cod liver oil (10 percent by weight of food) for 3 weeks prior to the experiment, and 9 animals receiving no treatment served as controls. The number of emboli was significantly reduced in the heparin group, but there was no accompanying improvement in capillary perfusion. In contrast, in the cod liver oil group, the number of emboli was not reduced, but there was significant improvement in capillary perfusion. These findings suggest that the harmful effect that platelet emboli have on the microcirculation is probably biochemical in nature (vasoconstriction) rather than related to simple mechanical obstruction to flow.

Anastomosis, Surgical↗

PubMed1992

Bile acid active and passive ileal transport in the rabbit: effect of luminal stirring.

The intestinal absorption of bile acids (BA) with different chemical structure has been evaluated in the rabbit, after intestinal infusion of different concentrations (0.25-30 mM) of BA, by mesenteric blood sampling. Cholic (CA), chenodeoxycholic (CDCA), ursodeoxycholic (UDCA) acid, free and taurine (T-) conjugated, together with glycocholic (GCA) acid and deoxycholic acid (DCA) were studied. The apparent uptake parameters were calculated. All conjugated BA showed active transport (T max, nmol min-1 cm-1 int.), with Tmax values in the following order: TCA > TUDCA > TCDCA; unconjugated BA showed passive uptake, with values in the following order: DCA > CDCA > UDCA > CA. GCA and CA showed both passive uptake and active transport. For all BA studied the % uptake in the ileal segment considered was less than 10%, BA uptake being thus limited by transport and/or diffusion kinetics, rather than by flow velocity. The liquid resistance to BA radial diffusion inside the lumen was evaluated, and the infusate-to-blood uptake parameters corrected for it, in order to get the uptake parameters from the epithelium-to-liquid interface to mesenteric blood: the apparent Km decreased, passive uptake coefficient increased, while Tmax was unchanged. The passive component of the uptake, corrected for the luminal resistance, correlated with the BA hydrophobicity (r = 0.963; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[Evaluation of atrial septum aneurysm with transesophageal echocardiography in cardioembolic cerebral ischemia].

The prevalence and characteristics of atrial septal aneurysm were identified by transesophageal echocardiography (TEE) in a multicenter prospective study. One hundred and seventy-seven consecutive patients were evaluated in 2 years and 2 groups were compared: Group 1, 51 patients with documented cerebral ischemia event; Group 2, 126 patients affected by cardiac disease referred for other reasons. Group 1 included patients selected among 352 patients admitted to the Neurological and Geriatric Division of our Hospital in the period of this study. Patients with stroke-related carotid lesions and patients with a negative TC scan were excluded from this study. Atrial septal aneurysm was identified in 15 patients: 8 in Group 1 (16%), and 7 in Group 2 (5%), with a significant statistical difference between the groups (p = 0.02). All patients with atrial septal aneurysm underwent before TEE transthoracic echocardiography, leading to a correct diagnosis in 10 of 15 cases (66%); all patients underwent 24-hours ECG monitoring. A right to left shunt was detected by contrast echocardiography in 9 patients, 6 in Group 1 and 3 in Group 2, (NS). A more pronounced shunt was evident in Group 1. There was no difference between the 2 groups with regard to associated cardiac disease, arrhythmias and type of atrial septal aneurysm. The thickness of the septum was greater in Group 1, with significant statistical difference (p = 0.002). It is concluded that atrial septal aneurysm, diagnosed by TEE, is a potential source of embolic events.

Adult↗

PubMed1991

Reduced neutrophil superoxide generation and plasma lipoperoxide levels in pigs fed with cod liver oil.

Circulating neutrophils, isolated from pigs fed for 8 weeks with a diet supplemented with CLO, had an accentuated n-3 fatty acid incorporation into the plasma membrane, as evidenced by an approximately four-fold greater n-3/n-6 ratio as compared with the control diet group. Moreover, the neutrophils of the CLO fed pigs produced less superoxide when stimulated with PMA or f-MLP, as well as showing a more prolonged latency period before O2(-)-generation. In the plasma of pigs fed with CLO there were higher levels of thiobarbituric reactive material and lipofuscin, while the content of GSSG was similar in both dietary groups. The results of this study indicate that dietary supplementation with CLO reduces the activation of circulating neutrophils and favours the presence in the plasma of lipoperoxides.

Animals↗

PubMed1991

Low-energy density CO2 laser as deep tissue stimulator: a comparative study.

A series of experiments on 12 pigs to verify the tissue penetrating capacity of a LED CO2 laser have been conducted to confront its effects with those of a infrared (IR) diode laser. The tissue target was the external femoral condilus of the right hind limb knee. The right knee was taken as control. After a series of laser radiations with both lasers for up to 60 days it was verified that the LED CO2 laser, contrary to what has been reported by physicists, can produce very active tissue stimulation on deep tissues with significant results. The authors suggest that the definition of physical properties of lasers should be redesigned in order to better understand their biostimulating effects on tissues.

Animals↗

PubMed1989

Long-term patency of regenerated neoaortic wall following the implant of a fully biodegradable polyurethane prosthesis: experimental lipid diet model in pigs.

The degradation of a polyurethane vascular prosthesis, the time course and characteristics of tissue ingrowth and prosthesis replacement, and the incidence of thrombosis have been investigated in 50 young pigs. A 6-7 cm long cone-shaped prosthesis was implanted in the infrarenal aorta of 50 young growing pigs which were sacrificed at intervals from 60 to 365 days. Ten animals were controls, 25 were given aspirin 10 mg/kg of body weight/day, and 15 were fed with cod liver oil. Aortography, done at 30, 60, and 90 days, showed 100% of implants were thrombosed in the surviving controls, 55% of the aspirin group had patent grafts, and 100% of animals in the lipid diet group had patent grafts. At final graft retrieval, the aspirin group showed only three patencies, while in the lipid diet group seven out of nine animals were patent. The laboratory and morphological studies indicated that all patent prostheses were lined with tissue that resembled the intima of native aorta with a layer of smooth muscle cells which appeared complete at 180 days. From these data we conclude that the biodegradable polyurethane vascular prosthesis is reliable for experimental implants in a pig model. The lipid-rich diet of polyunsaturated fatty acids potentiates long-term patency, perhaps by preventing platelet aggregation and thrombosis, and allowing the growth of a neoendothelium and neomedia within the lumen of the prosthesis, which slowly degrade towards fatty tissue and form neoadventitia.

Animals↗

PubMed1989

Prevention of platelet aggregation by dietary polyunsaturated fatty acids in the biodegradable polyurethane vascular prosthesis: an experimental model in pigs.

A 6-7 cm long degradable polyurethane vascular prosthesis was implanted in the infrarenal aorta of 25 young growing pigs, sacrificed from day 30 to 365 to study the processes of degradation and tissue growth, the characteristics of prosthetic substitutes and the incidence of thrombosis. Ten animals were used as controls and 15 were fed with cod liver oil (25 ml twice daily). Aortography performed at day 30, 60 and 90 showed 100% thrombosed implants in the controls, while in the lipid diet fed animals there was 100% patency. At graft retrieval, there were 7 patent grafts out of 9 in the cod liver oil fed animals. Laboratory tests indicated that the lipid diet rich in n-3 polyunsaturated fatty acids induces significant modifications of lipid metabolism preventing platelet aggregation. These data correlate well with findings of the morphological studies showing that all patent prostheses are lined with tissues similar to the endothelium of the native aorta with a mid layer made of circular and longitudinal smooth muscle cells well differentiated at day 180. These data show that the essential polyunsaturated fatty acid rich diet is able to prevent thrombosis of the biodegradable polyurethane vascular prosthesis. The combination of a synthetic material and the lipid diet experimental model, makes it possible to assess the long-term tissue-synthetic material interaction and the process of tissue growth.

Animals↗

PubMed1987