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Biomedical subjects

M Collini

Publications and source records attributed to M Collini.

At least 19 recordsLinked to original sources
PubMed2006

Temporal myofascial flap in reconstructive surgery of the oral cavity.

AIM: The temporal myofascial flap is a simple, rapid and reliable surgical method for immediate reconstruction of facial defects: indications in the light of modern anatomical knowledge and personal experience, with the accent on achieving an appropriate access route without damaging the facial nerve. METHODS: Our series covers the period from January 1999 to December 2004, during which time myofascial flaps of temporal muscle were used for immediate reconstruction in 20 surgical oncological cases involving the face and neck. RESULTS: Postoperative progress was regular; no lesions of the facial nerve were observed, nor any cases of flap necrosis, including partial. Epithelialisation could already be observed as early as 15 days postsurgery without skin grafting being employed. CONCLUSIONS: Application of a Medpor prosthesis eliminates the only negative outcome from the aesthetic standpoint, related to harvesting the muscle from the fossa.

Adenocarcinoma↗
PubMed2005

Selective fluorescence recovery after bleaching of single E2GFP proteins induced by two-photon excitation.

We report the two-photon excitation and emission or a recently developed green fluorescent protein (GFP) mutant, E(2)GFP. Two main excitation bands are found at 780 and 870 nm. Blinking and irreversible and reversible bleaching were observed. Fluorescence blinking occurs in the millisecond range and has been ascribed to conversions between the neutral, anionic and dark zwitterionic states. Bleaching is observed after approximately 10 to 400 ms depending on the excitation power, and it is probably due to a conversion to a dark state. The striking feature of this GFP mutant is that the fluorescence can be recovered with very high efficiency only upon irradiation at 720 +/- 10 nm. This GFP mutant therefore seems promising as an almost permanent chromophore for two-photon excitation (TPE) microscopy or for applications in single-molecule memory arrays.

Animals↗
PubMed2005

Treatment of lower lip cancer: an experience of 48 cases.

The article reports results obtained in 48 cases of lower lip cancer. Tumor classified as T1 or T2, requiring a resection up to 60% of the lower lip, were treated with the stair-case technique. Nine patients were treated with the bilateral symmetrical stair-case technique since their lesions were located medially, while 23 were treated with the bilateral method using two asymmetrical flaps because their lesions were in paramedian position but larger than 2 cm. Ten patients required a unilateral flap. The cases classified as T3, in which the lesion required resection of more than 60% of the lip, were treated with the Bernard-Freeman-Fries technique.

Aged↗
PubMed2001

Rotational dynamics of curved DNA fragments studied by fluorescence polarization anisotropy.

The rotational dynamics of short DNA fragments with or without intrinsic curvature were studied using time-resolved phase fluorimetry of intercalated ethidium with detection of the anisotropy. Parameters determined were the spinning diffusion coefficient of the DNA fragments about the long axis and the zero-time ethidium fluorescence anisotropy. We find a significant decrease in the spinning diffusion coefficient for all curved fragments compared to the straight controls. This decrease is likewise evident in rotational diffusion coefficients computed from DNA structures obtained by a curvature prediction program for these sequences. Using a hinged-cylinder model, we can identify the change in rotational diffusion coefficient with a permanent bend of 13-16 degrees per helix turn for the sequences studied. Moreover, for some of the curved fragments an increased flexibility has to be assumed in addition to the permanent bend in order to explain the data.

Algorithms↗
PubMed2000

New insight on beta-lactoglobulin binding sites by 1-anilinonaphthalene-8-sulfonate fluorescence decay.

The fluorescence time decay parameters of the beta-lactoglobulin-1-anilinonaphthalene-8-sulfonate complex have been investigated under physical and chemical perturbations (2 < pH < 8 and added electrolyte 0 < NaCl < 0.5 M) to obtain new insight on the nature of the protein binding interactions. A double exponential decay of the bound probe lifetime has been confirmed by the presence of a longer component, 11 to 14.5 ns, and a shorter component, 2.5 to 3.5 ns. The two lifetimes are ascribed to different binding modes associated also with different exposure to the solvent; in particular, the longer component is attributed to binding inside the hydrophobic beta barrel, while a "surface" site is suggested for the shorter component. A detailed analysis of the lifetime fractional intensities correlates the binding constants with ionic strength and supports the presence of electrostatic effects at both sites. A Debye-Hückel approach, applied to extrapolate the electrostatic free energy contribution vs. pH at vanishing ionic strength, gives interesting clues on the effective charge felt by the ANS ligands in the proximity of each site. In particular, binding is found to parallel the aspartate and glutamate titrations between pH 3 and pH 4.5; the "surface" site mainly responds to the presence of these local titrating charges while the "internal" site more closely follows the overall protein net charge.

Anilino Naphthalenesulfonates↗
PubMed1999

Evidence of heterogeneous 1-anilinonaphthalene-8-sulfonate binding to beta-lactoglobulin from fluorescence spectroscopy.

Steady-state and dynamic fluorescence titrations show that: (a) the complex between beta-lactoglobulin (BLG) and 1-anilinonaphthalene-8-sulfonate (ANS) displays a heterogeneous equilibrium with large changes in the binding strength vs. pH and ion concentration; and (b) the fluorescence response of bound ANS reveals two separate lifetimes that suggest two different sites (or binding modes). While steady-state fluorescence titrations yield effective values of the binding constant and of the bound ANS quantum efficiency, it is shown that, by combining steady-state fluorescence and lifetime decay of ANS, it is possible to give quantitative estimates of the association constants for each site. When heading from the acid (pH approximately 2) to the native state (pH approximately 6) the main result is a very large reduction of the effective binding constant. This and the results of titrations vs. ionic strength suggest that electrostatic interactions are a major contribution to ANS binding to BLG.

Anilino Naphthalenesulfonates↗
PubMed1995

Conformation of short DNA fragments by modulated fluorescence polarization anisotropy.

The technique of fluorescence polarization anisotropy (FPA) decay of intercalated ethidium has been used to study DNA conformation and dynamics, which are being recognized as primary determinants in transcription control and other cellular processes. Frequency modulated FPA when applied to two DNA molecules, a "straight" 50 base-pairs duplex fragment, and a bent fragment of similar length, has yielded different rotational diffusion coefficients for the two fragments. The data have been processed with an analytical model and with Brownian dynamics simulations, obtaining a good fit and a quantitative agreement between the two models. Both analyses have confirmed that one fragment can be described as a straight cylinder, while the other fragment is bent, with an angle estimated to be 45 degrees +/- 3 degrees. FPA has proved to be very powerful in determining simple conformations of short DNA duplexes and also particularly apt to probe the dynamical features of DNA fragments where conventional methods are either too cumbersome or fail to give quantitative results. In addition, the ligand no longer behaves ideally due to its complex structure and charge distribution. Thus for the protein the slope is no longer related simply to the net ligand charge, and the PB model gives a much larger slope than the LL model.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Composition↗
PubMed1995

Influence of ligands on the fluorescence polarisation anisotropy of ethidium bound to DNA.

The decay of the fluorescence polarisation anisotropy (FPA) of the ethidium-DNA complex has been measured by multifrequency phase fluorometry, in order to study the perturbations induced by the presence of different ligands on the torsional dynamics of DNA, a moderately flexible polymer that undergoes bending (flexure of the helix axis) and torsional (twisting of base pairs) motions. Two probes have been used together with ethidium: an intercalator, chloroquine, and a minor groove binding dye: hoechst 33258. Chloroquine is found to substantially modify the DNA torsional dynamics both in linear and in circularly closed DNAs only at high binding ratios, in agreement with previous reports [Wu et al. Biochem. 27 (1988) 8128]. The effective elastic constant becomes approximately three times larger when the dye/base pairs binding ratio is higher than 0.14. The minor groove ligand hoechst 33258, on the other hand, greatly increases the effective elastic constant to the point that at dye/base pairs ratios larger than 0.5, the effective elastic constant becomes stiffer by several orders of magnitude, suggesting a progressive hindering of internal motions. The results reported here show that DNA torsions are more effectively influenced by groove-binding molecules than by intercalators and it is expected that the large perturbation of the former ligand may be useful when describing the change in the dynamical properties induced by DNA binding proteins. FPA in the frequency domain, the technique adopted throughout this work, has proved to be very sensitive to changes of the elastic constant that describes DNA torsional dynamics. Several computer simulations performed in order to predict the FPA time decay of intercalated ethidium have led to good agreement with the observed results.

Animals↗
PubMed1992

DNA torsional dynamics by multifrequency phase fluorometry.

The time decay of the fluorescence polarization anisotropy of calf thymus DNA-ethidium complexes is obtained from measurements with sine-modulated excitation employing the so-called multifrequency phase fluorometry. A torsional dynamics model developed by J. M. Schurr [(1984) Chemical Physics, Vol. 84, pp. 71-96] and translated into the frequency domain is found here to describe accurately DNA-ethidium fluorescence data collected under modulated excitation. At a low dye/DNA ratio (1:400) the value of the DNA torsional constant (alpha = 4.63 +/- 0.2 10(-12) dyne cm) fitting the data agrees very well with the known values of alpha. When the measurements are extended to a higher ethidium/DNA ratio, energy transfer effects between intercalated dyes are observed. A theoretical prediction of the donor and acceptor dye contributions to the fluorescence polarization anisotropy is made here, taking into account also dye-dye distance distributions.

Animals↗
PubMed1988

The pectoralis major myocutaneous flap. Experience in 100 consecutive cases.

The authors have made a study of 100 consecutive cases in whom a pectoralis major myocutaneous flap was employed for reconstruction after surgical ablation of advanced malignant tumours in the head and neck. The results obtained show that primary healing took place in 74% of cases with a relatively low incidence of complications. The authors therefore confirm the reliability of the pectoralis major myocutaneous flap, which, owing to its rich blood supply, offers the possibility of providing large cutaneous islands, and its proximity to the site of ablation provides a simple and reliable method which may be used in the majority of cases of immediate or delayed reconstruction of the cervico-maxillo-facial area.

Adult↗
PubMed1988

[Osteomas of the paranasal sinuses: review of the literature and personal cases].

The sinusal osteomas: a review of literature and personal cases. The osteoma is a osteogenetic benign tumour formed by a fully developed bone, characterized by a slow growth, which, as far as the maxillo-facial region is concerned, shows to be frequently located in the paranasal sinuses. The osteoma originates from one of the sinus walls and spreads into the sinus cavity itself producing symptoms related to a lesion space occupying. In the present report, taking into consideration 4 personal cases, some literature datas are examined concerning the epidemiology, clinical behaviour and especially the therapeutic implications to be adopted by the surgeon in the presence of sinusal osteoma.

Adolescent↗
PubMed1986

Total glossectomy without laryngectomy.

When cancer of the tongue reaches a large size (T3, T4) it is almost impossible to treat it successfully with radiotherapy. The only therapeutic possibility in such cases is, therefore, total glossectomy. This may be effected without laryngectomy and with immediate reconstruction using musculo-cutaneous flaps. Such an operation allows total removal of the tumour and is followed by an acceptable though impaired functional result. Eight cases subjected to total glossectomy without laryngectomy are presented and aspects of ablative and reconstructive surgery are discussed. A report is made of postoperative complications and of functional rehabilitation: mastication is certainly impaired. However, swallowing is regained rapidly and phonation, although altered, is still comprehensible. An acceptable quality of life and good possibilities for a return to a working life result.

Adult↗
PubMed1985

Temporary intranasal prosthesis for a surgical defect of septum and columella.

A temporary intranasal prosthesis for the treatment of a surgical defect of the septum and columella after resection for a neoplasm has been described. The prosthesis is applied as soon as possible after surgery, which will limit complications during healing. Silicone elastomer is used because its softness does not produce decubitus ulcer, and it will accurately fit the surgical defect. The prosthesis can be relined easily during the postoperative period.

Acrylic Resins↗
PubMed1984

[Benign neoplasms of the soft tissues of the oral cavity].

The Authors, starting from a statistical study of Gennari et al., point out the frequency of the benign neoformations in the soft tissue of the oral cavity. They describe then the most frequently findable histological forms and the problems posed to the clinic and the surgeon by some histological forms such as the mixed tumours of the minor salivary glands and the fibropapillomatosis of the vestibular fornices. The Authors conclude stating that they not always are harmless neoformations and easily surgically excisable.

Fibroma↗
PubMed1984

[Malignant centro-facial granuloma. Clinical contribution].

The mid-face malignant granuloma represents an exceptionally rare disease. Its etiology is unknown and the prognosis is dismal. Characteristics pathological features are represented by granulomatous, ulcerative and lesions, with a destroying tendency. The AA., in reporting a recently observed case of the disease, stress the difficulties encountered in the diagnosis and analyze its clinical course typically showing relapsing episodes. Therapeutic strategies adopted in the various phases of the disease are discussed.

Adult↗
PubMed1984

[Limitations in opening the mouth after temporal craniotomy. Observations on 3 clinical cases].

The authors describe 3 cases of mouth-opening limitations and dyskinesia of the remaining mandibular movements, of different degrees of severity, arisen following a cicatricial retraction of the temporal muscle, caused by neurosurgical accesses to the underlying encephalic regions. Having kept in mind the afflictions that could cause an analogous symptomatology, the authors stop to consider which is the most suitable kind of treatment (surgical or rehabilitative) in these specific cases. For both kinds of treatment, corresponding to the specific indications, they propose techniques confirmed by their personal experiences.

Adolescent↗
PubMed1983

[Comparative study of pre and post-operative dynamic respiratory indices in subjects undergoing total laryngectomy].

A spirometric measurement was carried out on patients with cancer of the laryn before and after surgery for total laryngectomy at the Istituto Policattedra of the University of Parma ENT Clinic. Postoperative spirometry was performed by means of a Vitalograph apparatus with the mouthpiece positioned right over the tracheal opening. The parameters considered were the dynamic respiratory indices (CV/MEVS - MEVS/CV). Forty patients was mostly based on the fact that, prior to laringectomy, all of them had been subjected to a spirometric measurement for aneasthesiologic purposes. According to the results obtained, the patients can be divided into three groups. The first group consists of 10 subjects in whom no improvement was observed in their MEVS value, which in some instances had actually worsened. The second group is composed of 20 patients in whom the spirometric values remained more or less steady. The third group comprises 20 patients who showed a marked improvement of their respiratory indices. In some of the latter patients the values obtained were even better than those in the normal range. However, the overall average results are not statistically significant, except for an average 9% improvement of MEVS due, as expected, to a reduction of the dead space following total laryngectomy and a corresponding, though very slight, 4% improvement of the Tiffenau ratio.

Aged↗