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Biomedical subjects

G Mancini

Publications and source records attributed to G Mancini.

At least 19 recordsLinked to original sources
PubMed2006

Cationic liposomes, loaded with m-THPC, in photodynamic therapy for malignant glioma.

In this study we investigated the feasibility of mixed liposomes formed by dimyristoyl-sn-glycero-phosphatidylcholine (DMPC) and cationic gemini surfactant (Gemini 1) loaded with the chlorin m-tetrahydroxyphenylchlorin (m-THPC), in photodynamic therapy (PDT) for glioma. To this aim, an in vitro study was carried out by employing various human glioblastoma cell lines (A172, DBTRG, LN229, U118). The following liposomal formulations were tested: (i) DMPC and Gemini 1; (ii) m-THPC in DMPC in the absence or (iii) in the presence of Gemini 1 in the molar ratio 8:2; 7:3, and 6:4. The presence of Gemini 1 significantly increased the intracellular uptake of chlorin in all cell tested although with a different extent: LN229>U118>A172>DBTRG. The cytotoxicity of chlorin-loaded liposomes was then tested by cloning efficiency performed on different cultures, before and after irradiation with laser light at 652nm, at a Fluence Rate of 200mW/s for 100s, with a total Fluence of 20J/cm(-2). In the absence of irradiation, the different liposomal formulations induced a cytotoxicity in less than 30% of glioblastoma cells. On the contrary, irradiation induced total destruction of all cultures treated with m-THPC/DMPC+Gemini 1 in the ratios 8:2, or 7:3, or 6:4.

Cell Line, Tumor↗
PubMed2006

Immediate loading on single NobelDirect implant. Case report.

A problem associated with implant-prosthetic rehabilitation on single implant is the unscrewing or fracture of the connecting screw. In this study the authors evaluate clinical results of the immediate loading on single NobelDirect implant. This innovative implant introduced by NobelBiocare is a single-piece implant including fixture and abutment in a single piece of Titanium in order to eliminate the problem of unscrewing or fracture of the connecting screw.

Adult↗
PubMed2005

In vitro selection of mutants of Streptococcus pneumoniae resistant to macrolides and linezolid: relationship with susceptibility to penicillin G or macrolides.

OBJECTIVES: To evaluate the rate of acquisition of resistance to linezolid and macrolides in Streptococcus pneumoniae isolates with different levels of susceptibility to penicillin and erythromycin. MATERIALS AND METHODS: Thirty strains of S. pneumoniae were tested by serial passages in subinhibitory concentrations of each antibiotic by the spiral method. The four copies of the 23S rRNA rrl gene of parent strains and linezolid-resistant mutants were amplified and sequenced. RESULTS: The rate of acquisition of macrolide resistance did not differ when C-14 and C-16 macrolides were tested. Resistance to linezolid in strains susceptible to penicillin and erythromycin was difficult to produce. For mutants with low-level resistance to linezolid the cut-off value of the MIC was between 6 and 8 mg/L depending on the strain. All linezolid-resistant mutants displayed a mutation in 2-4 copies of the 23S rRNA rrl gene, mainly the G2576U mutation (27/30) with an additional C2610U mutation observed in certain mutants. Two new mutations were also noted, namely C2612A and C2571G. In three linezolid-resistant mutants no mutation was identified within the studied domain, suggesting another mechanism of resistance. CONCLUSIONS: Linezolid resistance in pneumococcal strains susceptible to penicillin and macrolides was more difficult to obtain than with macrolides. Increased resistance to these agents may therefore influence the clinical use of linezolid.

Acetamides↗
PubMed2005

Prevention of work related eye injuries: long term assessment of the effectiveness of a multicomponent intervention among metal workers.

BACKGROUND: Systematic assessments of the effectiveness of interventions to prevent work related eye injuries are needed. AIM: To investigate the long term effectiveness of a multicomponent prevention campaign. METHODS: The campaign (conducted in collaboration with the local Employers' Association and Trade Unions) targeted all 237 metal-ware factories in the district of Imola, Italy. Based on preliminary inspections, the main intervention included distribution to all factories of specific educational brochures and broadcasting/publication of television/radio programmes and local newspaper articles containing expert advice on the subject. This was followed by a four year "post-intervention reinforcement" period of unannounced official inspections. Main outcome measures analysed were eye injury rates (versus non-eye injury rates) among metal workers during "pre-intervention" (1988-90), "peri-intervention" (1991-92), "post-intervention reinforcement" (1993-96), "late post-intervention" (1997-2000), and "very late post-intervention" (2001-03) periods with respect to two comparison sectors (construction and wood/ceramics). RESULTS: A Poisson regression in which the eye injury rates were modelled for each sector, period, and interaction, adjusting for non-eye injury rates, was chosen. The periods did not by themselves determine an overall reduction in eye injuries. The period/sector interaction terms were related to significant reductions for the metal sector when crossed with the "post-intervention reinforcement" (IRR = 0.77, 95% CI 0.61 to 0.97; % decline = 23.4), the "late post-intervention" (IRR = 0.63, 95% CI 0.50 to 0.79; % decline = 37.4), and the "very late post-intervention" (IRR = 0.58, 95% CI 0.43 to 0.77; % decline = 42.4) periods, suggesting a sustained reduction in eye injury risk following the main intervention. CONCLUSION: Results suggest that a carefully coordinated, extensive, multicomponent intervention can lead to lasting reductions in the burden of eye injuries.

Accidents, Occupational↗
PubMed2001

On-column deracemization of an atropisomeric biphenyl by quinine-based stationary phase and determination of rotational energy barrier by enantioselective stopped-flow HPLC and CEC.

The reversible enantiomerization of axially chiral 2'-dodecyloxy-6-nitrobiphenyl-2-carboxylic acid was studied in the presence of a brush type chiral stationary phase based on O-(tert-butylcarbamoyl) quinine as chiral selector unit by stopped-flow high-performance liquid chromatography (sfHPLC) and capillary electrochromatography (sfCEC). After initial separation of the enantiomers in the first section of the column, the flow was stopped and the resolved species allowed to enantiomerize on-column. From this conversion, which could be determined from the enantiomeric ratios at different enantiomerization times, kinetic rate constants were calculated. By sfHPLC at a constant temperature of 15 degrees C, kinetic rate constants in the presence of the CSP were found to be 4.1 x 10(-5) s(-1) and 2.2 x 10(-5) s(-1) for the (-) and (+)-enantiomers, respectively, corresponding to half-lives of 279 and 530 min. Thus, apparent activation energies of enantiomerization were calculated to be 93.0 and 94.6 kJ mol(-1) for the (-) and (+)-enantiomers. On the macroscopic level, the apparent difference of rotational energy barriers and kinetic rate constants for both enantiomers is reflected as deracemization. For example, starting from a racemic mixture, an enantiomeric excess (ee) of 14% was seen in the stopped-flow HPLC experiment described after an enantiomerization time of 220 min at 15 degrees C, and a maximal ee of 17% can be approximated after infinite enantiomerization time. There is good agreement between HPLC and CEC results as well as their experimental errors, confirming that the new sfCEC technique may be a valuable and convenient tool to study interconversion processes.

Journal Article↗
PubMed2001

Characterization of mixed monolayers of phosphatidylcholine and a dicationic gemini surfactant SS-1 with a langmuir balance: effects of DNA.

Monolayers of a cationic gemini surfactant, 2,3-dimethoxy-1,4-bis(N-hexadecyl-N;N-dimethyl-ammonium)butane dibromide (abbreviated as SS-1) and its mixtures with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were studied using a Langmuir balance. More specifically, we measured the force-area (pi-A) curves and determined the elastic area compressibility modulus (C) as a function of lateral packing pressure and the mole fraction of the cationic lipid (X(SS-1)), with and without DNA in the subphase. Both SS-1 and POPC exhibited smooth compression isotherms, indicating their monolayers to be in the liquid expanded state. Even low contents (X(SS-1) < 0.05) of SS-1 in a POPC monolayer condensed the film dramatically, up to 20% at 30 mN/m. This effect is suggested to reflect reorientation of the P(-)-N(+) dipole of the POPC headgroup. Accordingly, the magnitude of the condensing effect diminishes with X(SS-1) and is not observed for mixed films of dioleoylglycerol and SS-1. Reorientation of the P(-)-N(+) dipole is further supported by the pronounced increase in monolayer dipole potential psi due to SS-1. The presence of DNA in the subphase affected the mixed POPC/SS-1 monolayers differently depending on the constituent lipid stoichiometry as well as on the DNA/SS-1 charge ratio. At a DNA concentration of 0.63 microM (in base pairs) condensation of neat POPC monolayers was evident, and this effect remained up to X(SS-1) < 0.5, corresponding to DNA/SS-1 charge ratio of 1.25. An expansion due to DNA, evident as an increase in DeltaA/molecule, was observed at X(SS-1) > 0.5. At a higher concentration of DNA (1.88 microM base pairs) in the subphase corresponding to DNA/SS-1 charge ratio of 3.75 at X(SS-1) = 0.5, condensation was observed at all values of X(SS-1).

DNA↗
PubMed2000

The spectrum of SLC17A5-gene mutations resulting in free sialic acid-storage diseases indicates some genotype-phenotype correlation.

Lysosomal free sialic acid-storage diseases include the allelic disorders Salla disease (SD) and infantile sialic acid-storage disease (ISSD). The defective gene, SLC17A5, coding for the lysosomal free sialic acid transporter was recently isolated by positional cloning. In the present study, we have identified a large number of mutations in SLC17A5 in patients presenting with either Salla disease or the ISSD phenotype. We also report for the first time the exon-intron boundaries of SLC17A5. All Finnish patients with SD (n=80) had a missense mutation changing a highly conserved arginine to cysteine (R39C); 91% of them were homozygotes for this old founder mutation. The compound-heterozygote patients, with the founder mutation in only one allele, presented with a more severe phenotype than did the homozygote patients. The same R39C mutation was also found both in most of the Swedish patients with SD and in a heterozygous form in five patients from central Europe who presented with an unusually severe (intermediate) SD phenotype. Ten different mutations, including deletions, insertions, and missense and nonsense mutations, were identified in patients with the most severe ISSD phenotype, most of whom were compound heterozygotes. Our results indicate some genotype-phenotype correlation in free sialic acid-storage diseases, suggesting that the phenotype associated with the homozygote R39C mutation is milder than that associated with other mutations.

Age of Onset↗
PubMed1999

Gradient plate method to induce Streptococcus pyogenes resistance.

In recent years, increasing numbers of Streptococcus pyogenes (GAS) strains displaying resistance to macrolides have been reported in Finland, Japan, Asia and Spain. Antibiotic use has been shown to be a risk factor for infection with and carriage of drug-resistant streptococci. The aim of this study was to compare in-vitro development of resistance of streptococci to beta-lactams (penicillin, amoxycillin, cefotiam and cefuroxime) and erythromycin by serial passages in subinhibitory concentrations of antibiotics (subMICs) by gradient plate method. Three clinical strains of GAS were tested. Two were susceptible to erythromycin (MIC = 0.015 mg/L and 0.013 mg/L) and one resistant. Serial passages were performed daily by gradient plate method until a four-fold increase of the MIC was achieved. GAS variants obtained after serial passages in beta-lactams had MICs increased at least four-fold. They remained susceptible to these antibiotics. With erythromycin, final MICs reached intermediate and resistant level. Results obtained in this study with erythromycin are in good correlation with clinical studies showing that prior exposure to macrolides may help to facilitate the emergence of drug-resistant strains of streptococci.

Anti-Bacterial Agents↗
PubMed1999

[Arteriovenous fistulas for hemodialysis: transposition of the cephalic veins, a personal experience].

BACKGROUND: Vascular access for hemodialysis has remarkably developed during these years. Since 1966 we have the Brescia-Cimino fistula which is considered nowadays the best choice for angioaccess. The transposed cephalic vein is the "variant" which has been evaluated in a single stage surgical technique. METHODS: A prospective and randomized study regarding 23 patients submitted to operation for first fistula during 1998. With a median follow-up of 10 months, these fistulas have been studied with echocolordoppler in order to verify their primary patency, diameter and blood flow in artery, in vein and anastomosis. RESULTS: Fistulas have been patented in all cases (15 males e 8 females) and used for dialysis after 3 weeks. No early or late complications have been observed. Mean diameter has been 1.2 cm with mean velocity of 1.8 m/sec, in artery mean velocity 2.3 m/sec and in vein 1.1 m/sec. CONCLUSIONS: Increasing length of life even for high critical patients like these with chronic renal failure underlines the need of surgical strategies which may improve the quality to life. This technique of transposed cephalic vein has the same advantages of direct fistulas also for those patients in which we should have used prosthetic grafts.

Adult↗
PubMed1998

Influence of smoking habits on Down's syndrome risk evaluation at mid-trimester through biochemical screening.

Expectant mothers who smoke have higher levels of maternal serum alpha-fetoprotein and lower levels of unconjugated estriol and total human chorionic gonadotrophin than non-smoking mothers. This significantly affects performance of screening for Down's syndrome. This study includes 22,169 pregnant women: 18,876 non-smokers, 2,660 smoking < or = 10 cigarettes/day, and 633 smoking > 10 cigarettes/day. Mean maternal age (32.6 years), maternal weight (60.5 kg), and gestational age (114.7 days) were similar or only slightly different between the three groups. To verify the effects of smoking on screening, we studied retrospectively 130 sequential Down's syndrome cases (47 from the screening program, 83 from the prenatal diagnosis program). The proportion of smokers in the Down's syndrome and unaffected pregnancies was similar, whilst the false-positive rate and detection rate, based on fetal outcome, differed: false-positive rates were 5.63% in smokers and 9.42% in non-smokers, and detection rate 55.6% in smokers and 83.0% in non-smokers. Since the prevalence of Down's syndrome pregnancies was the same at mid-trimester in smokers and non-smokers and the proportion of smokers was not related to maternal age, we propose an adjustment of the Down's syndrome risk evaluation algorithm according to smoking habits.

Adult↗
PubMed1997

Spherophakia associated with molybdenum cofactor deficiency.

Molybdenum cofactor deficiency is an autosomal recessive disorder characterized by lack of activity of the enzymes sulfite oxidase, aldehyde oxidase, and xanthine dehydrogenase or oxidase. The clinical manifestations are indistinguishable from those of isolated sulfite oxidase deficiency: craniofacial alterations, intractable neonatal convulsions, very severe mental retardation, lens dislocation, and death in the first decade of life. Lens dislocation is found in nearly all patients after neonatal age. In the present case it developed late (at the age of 8 years) and was preceded by bilateral spherophakia. We hypothesize that an abnormal relaxation of the zonular fibers is the cause of spherophakia in this disease; this causes lens dislocation eventually, after days, months, or years.

Child↗
PubMed1997

Repeat testing of mothers with high human chorionic gonadotrophin levels in Down's syndrome screening.

Multiples of medians of serum markers are assumed to be independent of gestational age: every algorithm used for Down's syndrome risk evaluation is based on this hypothesis. However, our former observations suggested that multiples of medians of human chorionic gonadotrophin in Down's syndrome are dependent on gestatational age. Furthermore, observations on 84 Down's syndrome cases confirmed that human chorionic gonadotrophin multiples of medians in samples drawn at 15-17 weeks are approximately 10% lower than in samples drawn at 18-21 weeks, thus showing that the human chorionic gonadotrophin concentration decreases about 10% less than expected. The control group comprised 554 women with two blood samples and normal human chorionic gonadotrophin at first sampling. A further group of 532 women with multiples of medians at first sampling > 1.8 was examined with the aim of excluding an association between the human chorionic gonadotrophin trend in Down's syndrome and high starting values. The trend is peculiar to human chorionic gonadotrophin in Down's syndrome pregnancies and may help to explain the increase in detection rate with gestational age. Based on these findings, screening can be optimized, thus improving performance.

Adult↗
PubMed1996

Microembolization from a carotid mural thrombus detected by transcranial Doppler.

Over the last few years, many authors have described the possibility of using transcranial Doppler to demonstrate the passage of microemboli in the cerebral arteries. We report the case of a 44-year-old woman with thrombotic diathesis and thrombocytosis who was admitted twice within a short period of time (one and a half months) to a neurological department because of multiple cerebral infarctions. On the occasion of the second admission, a colour-Doppler examination of the epiaortic vessels, which had previously been negative, showed a carotid lesion due to a mural thrombus and, on the same side as the carotid lesion, transcranial Doppler detected short-duration, high-intensity signals in the middle and anterior cerebral arteries, an expression of the passage of microemboli. As already described by other authors in similar clinical situations, our case confirms that transcranial Doppler can identify the passage of microemboli in the circle of Willis.

Adult↗
PubMed1996

Patent foramen ovale and transcranial Doppler. Comparison of different procedures.

BACKGROUND AND PURPOSE: The capability of transcranial Doppler sonography (TCD) to detect a patent foramen ovale (PFO) has been established. However, which provocative maneuver and what timing of contrast injection are most effective to induce a right-to-left shunt has not yet been determined. METHODS: We selected 38 cerebrovascular patients (21 men, 17 women) with positive contrast study for PFO on transesophageal echocardiography. Patients underwent a TCD with bilateral monitoring of the middle cerebral arteries (MCAs) and injection of a contrast solution. The injection was repeated (1) during normal breathing (basal conditions); (2) before Valsalva maneuver (VM); (3) during VM; (4) immediately after VM; and (5) during cough. The latency time and the total number of microbubbles for each side were recorded. RESULTS: TCD found positive results for PFO in 30 patients. Twenty were positive even during basal conditions. The number of positive cases varied according to the timing of the VM in relation to the contrast injection: 28, 25, and 27 cases were positive when the injection was performed before, during, and after VM, respectively, while 26 were positive during cough. There were significant differences in the number of microbubbles in the MCAs between the procedures (P < .001, ANOVA): the highest number was detected in the injection before VM and the lowest number during basal conditions (P < .001, Wilcoxon's test with Bonferroni's correction). The latency time was significantly shorter when the injection followed VM. CONCLUSIONS: The injection performed before VM appeared to be the most effective TCD procedure in determining the transit of microbubbles through a PFO and subsequently in the MCAs.

Adult↗
PubMed1996

[Adrenal adenoma or hyperplasia? Problems of differential diagnosis in an unusual case of primary hyperaldosteronism].

Although primary hyperaldosteronism is an uncommon cause of hypertension, it is the most common form of renin-independent hypermineralocorticoidism. The plasma aldosterone concentration and PRA with orthostatic test and saline infusion test are very useful aids to make a diagnosis. In this case the inconsistency between hormonal data and morphologic images (TC and NMR) led us to a dilemma: it was a question of adrenal adenoma or hyperplasia? Because it was impossible to dose the 18-OH-corticosterone, we had to perform a iodocholesterol scintigraphy NP 59. To distinguish an hyperplasia as cause of this kind of hyperaldosteronism made us able to define a therapeutic program useful to hypertension control.

18-Hydroxycorticosterone↗
PubMed1996

[Leiomyosarcoma of the mesentery. A case report and clinico-diagnostic considerations].

Leiomyosarcoma of the mesentery is a rare neoplasm. The clinical manifestation is non-specific and preoperative diagnosis is often late. Mitotic activity shows no significant correlation with the biological behavior of neoplasm. The surgical excision is the therapy of choice but local recurrence is high. The authors report a case of leiomyosarcoma which was treated by surgical removal and underline the diagnostic difficulties.

Aged↗
PubMed1996

[The role of Enterobius vermicularis in etiopathogenesis of appendicitis].

The authors present 14 cases of enterobiasis of appendix observed between 1991-94, on a total of 1093 appendectomies. The presence of the parasite was associated, in the majority of cases, to a chronic appendicitis. The symptomatology imitates an attack of acute appendicitis, but the true nature of the disease is diagnosed only through a histological examination. There is probably an etiopathogenic relationship between. E. vermicularis and chronic appendicitis, whereas the relationship between the parasite and acute appendicitis is rare and very disputed.

Adolescent↗