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Biomedical subjects

G Luciani

Publications and source records attributed to G Luciani.

At least 19 recordsLinked to original sources
PubMed2007

Effect of the solution flow rate on the in vitro bioactivity of 2.5CaO x 2SiO(2) glass.

A comparative study of in vitro bioactivity of 2.5CaO x 2SiO(2) glass has been carried out by soaking it in a simulated body fluid, with continuously and periodic exchange of this solution (dynamic and differential protocols). Dynamic assays were carried out at different solution flow rates, 3 mL/h, 6 mL/h, 12 mL/h, to study the influence of flow rate on glass reactivity. Glass surface was studied by Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy so as to compare the behavior in the two procedures, revealing that in both cases an apatite layer is formed on the glass surface, although there are differences on deposition rate and morphology, which are also influenced by the solution flow rate.

Adsorption↗
PubMed2006

Anorexia in hemodialysis patients: an update.

Anorexia, defined as the loss of the desire to eat, is relatively common in hemodialysis (HD) patients, occurring in one-third of cases. The pathogenesis is essentially unknown. It has been proposed that uremic toxins as middle molecules, inflammation, altered amino-acid pattern, leptin, ghrelin, and neuropeptide Y are involved. Anorexia reduces oral energy and protein intakes, thus contributing to the development of malnutrition and cachexia. Unquestionably, it contributes to poor quality of life. The clinical relevance of anorexia as an independent prognostic factor in HD patients is a matter of debated issue. The treatment of this debilitating condition is based on a therapeutic strategy which may include daily dialysis sessions and nutritional counseling. Normalization of plasma branched-chain amino acids through branched-chain amino acids supplementation may decrease anorexia and improve energy and protein intake. The role of megestrol acetate as appetite stimulant needs to be validated through adequate randomized trials. Subcutaneous ghrelin administration and melanocortin-receptor antagonists appear promising therapeutic interventions.

Anorexia↗
PubMed2006

Swelling properties and bioactivity of silica gel/pHEMA nanocomposites.

A novel hydrogel based on 2-hydroxyethyl- methacrilate and SiO(2) nanoparticles was prepared. The filler was added at a concentration of 30% w/w of silica nanoparticles to the mass of polymer. The composite material was characterised as far as concerns swelling behaviour in comparison to pHEMA. Swelling ratio of modified pHEMA was higher. Bioactivity of both SiO(2) nanoparticles and the modified hydrogel was evaluated by soaking samples into a simulated body fluid (SBF). FT-IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive system (EDS) results suggest silica nanoparticles keep bioactive in the polymer. SiO(2) filler in a p(HEMA) matrix makes the composite bioactive. Therefore, these composites can be used to make bioactive scaffold for bone engineering.

Absorption↗
PubMed2006

Small bowel intussusception: what is the role of laparoscopy?

Small bowel intussusception in adults is a rare surgical disease which almost always occurs as a complication of either benign or malignant lesion of the bowel that is working as a leading point. In adults, the surgical approach consists of the resection of the bowel involved to ensure the excision of the lesion below. The authors report a case of ileocecal intussusception occurred in a young woman, 35 years old, observed for abdominal pain and signs of small bowel occlusion. She underwent surgical resection of the ileocecal segment with laparoscopic approach. The authors discuss the feasibility of the laparoscopic approach in this rare surgical disease and its benefits in terms of patient's postoperative comfort and outcome.

Journal Article↗
PubMed2004

Poly(2-hydroxyethyl methacrylate) biomimetic coating to improve osseointegration of a PMMA/HA/glass composite implant: in vivo mechanical and histomorphometric assessments.

Bone implants must simultaneously satisfy many requirements, even though the surface properties remain a crucial aspect in osseointegration success. Since a single material with a uniform structure cannot satisfy all of these requirements, composite materials specifically designed for orthopedic or dental implant application should be envisaged. Two poly(methylmethacrylate)/hydroxyapatite composites reinforced by E-glass fibres, uncoated (PMMA/HA/Glass) and poly(2-hydroxyethyl methacrylate) (PMMA/HA/Glass+pHEMA) coated by the biomimetic method, were mechanically (push-out test) and histomorphometrically (Affinity Index, AI) investigated in an in vivo rabbit model. Cylindrical implants (diameter 2 mm x 5 mm length) were inserted into rabbit femoral cortical (mid-diaphysis) and cancellous (distal epiphysis) bone, under general anesthesia. The highest values of push-out force and ultimate shear strength were observed for the PMMA/HA/Glass at 12 weeks, which significantly (p < 0.001) differed from those of PMMA/HA/Glass+pHEMA at the same experimental time and from those of PMMA/HA/Glass at 4 weeks. At both experimental times, significantly (p < 0.0005) lower values of AI were observed in the PMMA/HA/Glass+pHEMA versus PMMA/HA/Glass (distal femoral epiphysis: 4 weeks = 33%; 12 weeks = 19%; femoral diaphysis: 4 weeks = 15%; 12 weeks = 11%). The good mechanical and histomorphometric results obtained with PMMA/HA/Glass should be followed by further evaluation of bone remodeling processes and mechanical strength around loaded PMMA/HA/Glass implants at longer experimental times. Finally, the biomimetic method applied to pHEMA needs to be further investigated in order to improve the positive effect of SBF on pHEMA and to enhance the coating adhesion.

Animals↗
PubMed2002

Effect of the substitution of M2O3 (M = La, Y, In, Ga, Al) for CaO on the bioactivity of 2.5CaO x 2SiO2 glass.

Glasses were prepared whose compositions are defined by the following general formula: (2.5 - x)CaO x x/3M2O3 x 2SiO2 (0 < or = x < or = 0.6) (M = Ga, Al, In). Their bioactivity was studied "in vitro" by soaking the glasses in a simulated body fluid (SBF). The consequent formation of calcium phosphate layer was studied by means of electron microscopy (EM) equipped with an energy-dispersive system (EDS) for elemental analysis and Infrared (IR) spectroscopy. The results are compared to the literature relative to the substitution of La2O3 and Y2O3 for CaO. It is observed that, in general, the substitution of M2O3 for CaO in the binary CaO-SiO2 glass composition progressively reduces the ability to form a calcium phosphate layer on the surfaces exposed to simulated body fluid (SBF). The composition limit can be related to the ionic field strength of the substituting cation and to the CaO content of the base glass. According to the mechanism reported in the literature a silica gel-like surface layer initially forms on the surfaces exposed to SBF. The observed results can be attributed to the effect of the substitution of M2O3 for CaO on the acidic properties of the silanolic groups.

Aluminum↗
PubMed2002

Hydroxyapatite coating of titanium by biomimetic method.

The biomimetic method was used in order to deposit, on titanium substrates, an hydroxyapatite (HA) coating. The bioactive HA layer was obtained by using, in the first stage of the process, a glass having the composition 2.5CaO.2SiO(2) different from the one proposed for the application of the biomimetic method. This glass can be obtained via sol-gel, a method that allows one to obtain, easily, very pure products. The growth of HA crystals was confirmed by Fourier transform infrared, SEM, EDS and X-ray photoelectron spectroscopy (XPS) results. The experimental results suggest that, as reported in the literature for other supports, the silicate ions released from the glass in the first stage bind themselves to the titanium support. In particular, from XPS analysis it is evident that the titanium substrate is well covered by a calcium phosphate layer of the type of HA.

Journal Article↗
PubMed2001

Improvement of swelling properties of poly(2-hydroxyethyl methacrylate) hydrogel by means of biomimetic method.

Poly(2-hydroxyethyl methacrylates) (PHEMAs) structurally modified by means of polymer blends and random copolymers are intensively studied in order to improve mechanical properties. It was recently shown that a hydroxyapatite coating, which should improve the bonding of this biomaterial to the bone, can be obtained by means of the biomimetic method. When PHEMA is submitted to the biomimetic method, its swelling ratio is improved. This can be ascribed to the deposition of a silicatic layer, which improves the hydrophilicity, on the surface of the internal pores during the first stage of the method. This appears to be a valuable result for producing modified PHEMAs with improved mechanical properties and good swelling. The experimental results indicate the following: stronger interactions with the water molecules are set up, an induction period is observed that is linked to the rate of the reactions occurring at the surface of the glass and the establishment of a convenient concentration of the silicate ions at the external surface of the polymer, and the diffusion of simulated body fluid into the pores is the limiting stage of the process.

Biocompatible Materials↗
PubMed1998

Antioxidant status and dialysis: plasma and saliva antioxidant activity in patients with fluctuating urate levels.

The present study is concerned with the influence of processes occurring during dialysis on the antioxidant capacity of plasma and saliva. The biological fluids were also tested for uric acid and total protein content. Before hemodialysis, plasma antioxidant status of hemodialyzed patients appears slightly higher than the corresponding status in normal subjects; after hemodialysis it is found unchanged. The result can be explained by a balance between a reduction in uric acid plasma content, due to the dialytic procedure, and an increase in protein content, possibly due to a dialysis-related hemoconcentration. Moreover, pre-dialysis total antioxidant capacity of whole saliva samples is higher than in healthy individuals and drastically decreases towards normal values following dialytic procedure. Our data indicate a certain concentration of the uric acid in the saliva of hemodialyzed patients and evidence that both total protein concentration and uric acid level show a good correlation with saliva total antioxidant capacity, suggesting that proteins are major antioxidants of this fluid. Further observations are needed to assess whether this improved saliva antioxidant ability has any consequence on the periodontal conditions of hemodialyzed subjects.

Adult↗
PubMed1996

Influence of blunt needles on surgical glove perforation and safety for the surgeon.

BACKGROUND: Round-tipped blunt needle (BN) may decrease the risk of needlestick injuries and hand contamination. We prospectively determined the incidence of glove perforations in emergency abdominal procedures and the efficacy of BN in increasing the safety for surgeons. METHODS: Two hundred patients were randomized to undergo closure of the abdominal fascia using sharp needle (SN) or BN. Gloves were tested at the end of the procedure. RESULTS: Surgeons had 14 needlestick injuries and 76 perforations recorded in 69 pair of gloves. Sharp needles were responsible for all injuries and 58 (76%) perforations (P < 0.00004 and P < 0.00001, respectively). This difference was still higher when considering the perforations related to the abdominal fascia closure (BN 7% versus SN 50%; P < 0.0006). CONCLUSION: The risk of glove perforation is sevenfold greater if SN are used. Blunt needles reduce sharp injuries and improve safety for surgeons.

Accidents, Occupational↗
PubMed1995

Paroxystic hypertension in a long-term hemodialyzed patient. Successful adrenalectomy for a dopamine-producing pheochromocytoma.

Pheochromocytoma (Pheo) is an uncommon neoplasm producing blood pressure troubles and it may be undiagnosed in chronic dialyzed patients in whom hypertension is a common finding. The symptoms in Pheo syndrome depends on the prevalent catecholamine released, the most common being epinephrine (E) and norepinephrine (NE). Recently, a particular clinical picture has been described for dopamine (DA)-producing Pheos, in whom a normo-hypotensive status is more often observed. The authors report a case of mainly dopamine-producing Pheo in a long-term dialyzed patient, successfully treated with adrenalectomy. The main steps in diagnosis and preoperative management are described and debated also in view of the particular background produced by the end-stage renal failure. The common imaging techniques adopted for adrenal medullary neoplasms (US, CT, MIBG scintiscan) confirmed to be decisive for diagnosis; HPLC assay of plasma catecholamines is the only biochemical test available in these patients although its significance is questionable due to the poor knowledge of catecholamine metabolism in chronic renal failure. The clinical findings observed in this case seem in disagreement with those already reported in DA producing Pheos. Pheo in hemodialyzed patients is a rare event and it may be hidden by other more common causes of hypertension. However, more awareness from the medical staff allows to diagnose the neoplasm correctly by the currently available methods and to plan a safe surgical therapy also in high-risk patients.

Adrenal Gland Neoplasms↗
PubMed1992

Halothane does not alter Ca2+ affinity of troponin C.

Troponin C has been suggested as a possible target for the negative inotropic action of volatile anesthetics. This study has examined the effect of halothane on the structure and response of isolated cardiac troponin C to Ca2+ and the response of skinned soleus and cardiac muscle fibers to Ca2+. The high-affinity Ca(2+)-binding sites of cardiac troponin C were assessed by measurement of the change in intrinsic tyrosine fluorescence and ultraviolet circular dichroism in response to Ca2+ in the presence and absence of halothane. Halothane (0.9 mM, 1.4%) did not alter the 45% enhancement in intrinsic tyrosine fluorescence that occurs with saturation of the high-affinity sites or change the Ca2+ concentration at which half-maximal enhancement occurred. The molar ellipticity in the far ultraviolet region, a measure of the secondary structure, increased to a similar extent with addition of 10(-6) M Ca2+ in the absence and presence of 1.0 mM (1.6%) halothane. The binding rate of the sulfhydryl reagent, 5,5'-dithiobis (2-nitrobenzoic acid), to troponin C in response to Ca2+ titration was used as a measure of the integrity of the low-affinity Ca(2+)-binding site in troponin C in the presence and absence of 1.0 mM (1.6%) halothane. The rate of reaction was stimulated twofold, and the half maximal effect was observed at pCa 4.8 +/- 0.2 in both control and halothane-treated samples. Halothane (5 mM; 7.8%) did not change the pCa/tension response of skinned soleus fibers; the data were fit to the Hill equation and yielded dissociation constants of 6.2 x 10(-7) M for control and halothane-treated specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Surgical day hospital: technical possibilities and organizational model].

The Authors propose an organizational model for a surgical day hospital program, which is being used for a pilot day surgery unit in the I Department of Surgery of the Rome University "La Sapienza". The program requires little capital investment, as it is closely linked, geographically and administratively, to the main surgical unit, and uses the present staff, facilities and support services. The model is based on a computerized LAN (Local Area Network), providing fast recording, scheduling, management and trannsfer of medical data for each patient. The present situation is reported in detail. Data from the authors' outpatient department for 1988, have been recorded and elaborated. The results show a low use of surgical day care, limited to minor surgical procedures, and with not a single operation performed under general anesthesia. The authors hope to see a growth in the use of day surgery and a more selective use of inpatient care.

Adolescent↗
PubMed1986

Acute controlled study of the dose-response relationship of fenoterol, ipratropium bromide and their combination.

A double-blind study was carried out in a group of 9 patients with partially reversible airway obstruction, to evaluate the bronchodilator effect of gradually increased doses of fenoterol (cumulative doses: 100, 200, 400, 800 and 1,600 micrograms), ipratropium bromide (40, 80, 160, 320 and 640 micrograms) and a combination of these (100 + 40, 200 + 80 micrograms, etc.), denominated Duovent. The three treatments were carried out at random at the same time on 3 days, usually not consecutive days, whereby 1, 1, 2, 4 and 8 puffs (altogether 1, 2, 4, 8 and 16 doses) of each product were given in identical pressurized aerosols at intervals of 60 min. Respiratory (spirometry and flow-volume curve) and cardiovascular (blood pressure, heart rate) parameters were measured under basal conditions and 60 min after each administration. On average, with all three products, the bronchodilatory effect showed a linear correlation with the logarithm of the dose given. With the same number of puffs the side-effects (tremor in particular) of the combination fenoterol and ipratropium bromide or Duovent (FIB) were markedly fewer than those of fenoterol, while ipratropium bromide was very well tolerated. The three dose-response curves (parallel) show that, in respect of an increase in FEV1, 1 puff of Duovent (100 micrograms fenoterol + 40 micrograms ipratropium bromide) is approximately equal to 2 puffs of fenoterol (200 micrograms) and 4 puffs of ipratropium bromide (160 micrograms). FIB, therefore, makes it possible to maintain the same bronchodilatory effect as the full dose (400 micrograms) of fenoterol while improving the therapeutic value.

Adult↗
PubMed1986

Tolerance to inhaled Duovent. A long-term study.

Fenoterol with ipratropium bromide (Duovent) is a recently used combination between an anticholinergic and a beta-adrenergic drug useful in obtaining a more effective bronchodilatation and/or reducing the single drug doses. It has been suggested that, as in the case of beta-agonists, its clinical efficacy may be limited by the development of tolerance. We studied the effects of inhaled Duovent in 15 asthmatic patients for 3 months, using a rigidly controlled protocol. Appropriate serial physiological measurements were made at regular intervals during the 90-day study. In all instances the day-one bronchodilator response was significant, prompt and sustained: at 1, 4, 8 and 12 weeks the response was statistically the same as on day 1. It is concluded that, when the important variables are properly controlled, no evidence of tolerance to long-term therapy with Duovent is demonstrable.

Adult↗
PubMed1986

Protective effect of Duovent versus salbutamol in long-term treatment.

The effect of the combination fenoterol-ipratropium bromide (Duovent) as a bronchodilator drug versus salbutamol and placebo was investigated in 20 patients with chronic obstructive lung disease in a random cross-over trial. Our study was performed not only to evaluate the bronchodilator response, but especially to quantify the possibly more prolonged action of Duovent versus salbutamol, based on registration of prevention of asthma attacks, time effects and protective activity, management and tolerance. Each patient received therapy for 3 weeks; in each week only one of the preparations: salbutamol, Duovent or placebo was used. Respiratory function tests were determined every week on the 3rd, 5th and 7th days at the same time exactly at 30 and 60 min after drug inhalation. Additionally we registered, for each patient, daily symptomatology (e.g., asthma attacks, cough, additional daily puff use, adverse reactions) by using a personal clinical diary. The results and analysis of the pulmonary tests (especially FEV1 and peak expiratory flow) confirmed the bronchodilator effect of both drugs, higher for Duovent but not sufficient to reach statistical significance. Clinical condition, regarding number, severity of asthma crises and additional puff use, showed a significant statistical variation for each symptom either as regards advantage of Duovent and salbutamol versus placebo, or advantage of Duovent versus salbutamol. Therefore, the results of this trial reveal an excellent bronchodilator effect of both drugs and confirm a higher clinical efficacy of Duovent if used in long-term treatment, with good tolerability.

Airway Resistance↗