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D Locatelli

Publications and source records attributed to D Locatelli.

At least 19 recordsLinked to original sources
PubMed2004

Endoscopic approach for the treatment of relapses in cystic craniopharyngiomas.

INTRODUCTION: Craniopharyngiomas are tumours of the central nervous system of dysontogenetic origin. They are most commonly localized in the sellar region and appear to originate from an embryogenetic defect of the Rathke cleft. It is universally accepted that radical surgery should be performed as first surgery because surgery after relapses usually causes more difficulty due to tighter adhesion to surrounding structures. It is essential when relapses occur to evaluate which technique to use for treatment. For this reason, any new approach is welcomed in order to have as many alternatives as possible. MATERIAL AND METHODS: In this paper we present the treatment, with a minimum follow-up of 4 years, of 5 paediatric patients affected by cystic craniopharyngiomas who went through first traditional surgery in other institutions and suffered relapses in various anatomical structures. One had a second successful endoscopic attempt at total gross resection. In 3 cases we endoscopically implanted a stent in the cystic cavity draining the cystic liquid out from the cystic cavity of the craniopharyngioma to the sphenoid sinus in order to form an accessory sinus. In 1 case a multiphase treatment has been undertaken. RESULTS: All patients treated using a transsphenoidal endoscopic approach are still living, without relapses and no postoperative complications. In particular, there where no episodes of vasospasm (a common complication reported in the literature when the "motor oil" comes into contact with the subarachnoid space) or infections. The patient treated using the multiphase approach recovered but suffered a recurrence 2 years later due to hypothalamic infiltration. DISCUSSION AND CONCLUSIONS: Craniopharyngioma relapse needs different treatments. Many alternative approaches have been reported but none of them is the first choice alternative. We believe endoscopic stent placement in the cystic cavity is an alternative method for the treatment of cystic relapses.

Adolescent↗
PubMed2000

Endoscopic approaches to the cranial base: perspectives and realities.

We describe the development of transnasal endoscopic approaches to the cranial base in an interdisciplinary series of 103 patients, including 13 in the pediatric age group. Our aim was to define, with the aid of different case reports, the possibilities of endoscopic techniques in tumor resection, fistula repair, the treatment of mucoceles and meningoceles, and of combined intracranial and endoscopic approaches. The advantages of these minimally invasive approaches are panoramic visualization, rapidity and reduction of the cosmetic and functional disabilities in comparison with other conventional approaches, and a better capacity for identifying and developing key landmarks for surgery. On the other hand, endoscopic surgery requires an exsanguine operation field, technical improvements in instruments, and specific skills. Interdisciplinary collaboration in endoscopic approaches has proved useful in integrating experiences without overlap between fields, and in broadening possibilities: in our opinion endoscopic approaches will certainly be important in the future of cranial base surgery.

Adolescent↗
PubMed1999

Dependence of fibroblast autofluorescence properties on normal and transformed conditions. Role of the metabolic activity.

The dependence of autofluorescence properties on the metabolic and functional engagement and on the transformation condition was studied on single cells. Normal Galliera rat fibroblasts at low subculture passage (cell strain), at high subculture passage (stabilized cell line), and transformed cell line derived from a rat sarcoma were used as a cell model. The study was performed by microspectrofluorometric and fluorescence imaging technique. The autofluorescence properties of cells were studied by excitation at two wavelengths, namely 366 nm and 436 nm, that are known to favor the emission of different fluorophores. Spectral shape analysis indicated that under excitation at 366 nm autofluorescence is ascribable mainly to coenzyme molecules, particularly to reduced pyridine nucleotides, while under excitation at 436 nm, flavin and lipopigment emission is favored. The energetic metabolic engagement of the different cell lines was analyzed in terms both of parameters related to anaerobic-aerobic pathways (biochemical assay) and of mitochondrial features (supravital cytometry). The results showed that the cell strain and the stabilized and transformed cell lines can be distinguished from one another on the basis of both overall fluorescence intensity and the relative contributions of spectral components. These findings indicated a relationship between autofluorescence properties and energetic metabolism engagement of the cells that, in turn, is dependent on the proliferative activity and the transformed condition of the cells. In that it is a direct expression of the energetic metabolic engagement, autofluorescence can be assumed as an intrinsic parameter of the cell biological condition, suitable for diagnostic purposes.

Animals↗
PubMed1998

Brain tissue autofluorescence: an aid for intraoperative delineation of tumor resection margins.

The intrinsic autofluorescence properties of biological tissues can change depending on alterations induced by pathological processes. Evidence has been reported concerning the application of autofluorescence as a parameter for in situ cancer detection in several organs. In this paper, autofluorescence properties of normal and tumor tissue in the brain are described, suitable for a real-time diagnostic application. Data were obtained both on ex vivo resected samples, by microspectrofluorometric techniques, and in vivo, during surgical operation, by means of fiberoptic probe. Significant differences were found in autofluorescence emission properties between normal and tumor tissues, in terms of both spectral shape and signal amplitude, that confirm the potential of autofluorescence as a parameter to distinguish neoplastic from normal condition. The noninvasiveness of the technique opens up interesting prospects for improving the efficacy of neurosurgical operations, by allowing an intraoperative delineation of tumor resection margins.

Brain↗
PubMed1998

Evolution of childhood central diabetes insipidus into panhypopituitarism with a large hypothalamic mass: is 'lymphocytic infundibuloneurohypophysitis' in children a different entity?

We report on a 15-year-old girl who had presented with acute onset central diabetes insipidus at the age of 8 years; this was followed by growth failure due to acquired growth hormone deficiency. Initial magnetic resonance imaging showed a uniformly enlarged pituitary stalk and absence of posterior pituitary hyperintensity. Frequent patient examination and magnetic resonance imaging gave unchanged results until after 5 years a large hypothalamic mass and panhypopituitarism were found. Dynamic magnetic resonance imaging documented hypothalamic-pituitary vasculopathy. Histopathological examination revealed perivascular inflammatory lymphoplasmic infiltrates with no granulomatosis or necrosis and negative staining for S-100 protein, suggesting autoimmune inflammatory disease (lymphocytic infundibuloneurohypophysitis?). The response to glucocorticoid pulses (30 mg/kg per day for 3 days i.v.) was favorable. the hypothalamic mass being halved and partial anterior pituitary function recovery maintained for 2 years after the start of treatment. We suggest that long-term surveillance is needed for isolated and chronic thickening of the pituitary stalk and that dynamic magnetic resonance imaging can contribute to the demonstration of hypothalamic-pituitary vascular impairment associated with local vasculitis.

Age of Onset↗
PubMed1998

Application of fluorescence resonance energy transfer techniques to the study of lectin-binding site distribution on Paramecium primaurelia (Protista, Ciliophora) cell surface.

Fluorescence resonance energy transfer (FRET) is a photophysical phenomenon occurring between the molecules of two fluorochromes with suitable spectral characteristics (donor-acceptor dye pair), and consisting in an excitation energy migration through a non-radiative process. Since the efficiency of the process is strictly dependent on the distance and reciprocal orientation of the donor and acceptor molecules, FRET-based techniques can be successfully applied to the study of biomolecules and cell component organisation and distribution. These techniques have been employed in studying Paramecium primaurelia surface membrane for the reciprocal distribution of N-acetylneuraminic acid (NeuAc) and N-acetylglucosamine (GlcNAc) glycosidic residues, which were found to be involved in mating cell pairing. NeuAc and GlcNAc were detected by their specific binding lectins, Limulus polyphemus agglutinin (LPA) and wheat germ agglutinin (WGA), respectively. Microspectrofluorometric analysis afforded the choice of fluorescein isothiocyanate and Texas red conjugated with LPA and WGA, respectively, as a suitable donor-acceptor couple efficiently activating FRET processes. Studies performed both in solution and in cells allowed to define the experimental conditions favourable for a FRET analysis. The comparative study carried out both on the conjugating-region and the non conjugating region of the surface membrane, indicates that FRET distribution appears quite homogeneous in mating-competent mating type (mt) I, whereas, in mating-competent mt II cells, FRET distribution seems to be preferentially localised on the conjugating-region functionally involved in mating cell pairing. This difference in the distribution of lectin-binding sites is suggested to be related to mating-competence acquisition.

Animals↗
PubMed1997

Enzyme-assisted cell photosensitization: a proposal for an efficient approach to tumor therapy and diagnosis. The rose bengal fluorogenic substrate.

Rose bengal, a xanthene derivative among the most efficient producer of singlet oxygen, was submitted to a chemical modification consisting in the introduction of an acetate group into the aromatic ring fluorophore structure. The acetate group acts as a quencher, thus inactivating both fluorescence and photosensitization properties of the molecule. In the modified structure, rose bengal acts as a fluorogenic substrate giving rise to the cellular reaction termed fluorochromasia. The acetate group is recognized by a carboxylic esterase activity that splits it. Removal of the quencher group results in restoring the native structure of photosensitizer inside the cells. The intracellular turnover of rose bengal acetate was studied in rat glioma-derived cultures cells, in terms of the balance of the processes of influx and enzyme hydrolysis of the fluorogenic substrate, and of the efflux of the fluorescent product. A large intracellular accumulation of photosensitizer is obtained when treatments are performed with the fluorogenic substrate, even at the drug concentration at which rose bengal does not enter the cells. The intracellular localization allows rose bengal to exert a more effective photosensitization effect. Provided that the quencher group is selected according to the metabolic properties of the tumor cells, the use of fluorogenic substrates as photosensitizer precursors could improve fluorescence diagnosis and the photodynamic therapy of tumors, exploiting the biological properties that distinguish pathological from normal conditions.

Acetylation↗
PubMed1996

CNS-85 trial: a cooperative pediatric CNS tumor study--results of treatment of medulloblastoma patients.

Between 1985 and 1989, 38 children with newly diagnosed medulloblastoma entered our therapeutic protocol. After surgery and postoperative staging assessments, patients were assigned to risk groups. Eleven with "standard-risk" (SR) tumors were treated with radiation therapy alone, while 27 with "high-risk" (HR) tumors received radiation therapy plus adjuvant chemotherapy with vincristine, methotrexate, VM-26, and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU). After a minimum follow-up of 5 years (range 5-9 years) 21/38 children had developed a recurrence or progression of their disease and 19/38 patients had died. Five-year event-free survival rates and 5-year total survival rates for all 38 patients were 47.4% and 50% respectively. The event-free survival rates at 5 years for SR and HR patients separately were 27.3% and 55.6%, respectively. The corresponding 5-year total survival rates were 27.3% and 59.3%. The differences were not statistically significant. Univariate analysis showed age at diagnosis to be the most important prognostic factor. Infants aged 5 years or less had a significantly shorter event-free survival time than older patients (P = 0.00897). Similar effects were found when total survival time was considered. There were significant differences in outcome in patients receiving different doses of radiation, suggesting a dose-response relationship. A Cox stepwise multivariate analysis showed age at diagnosis as the only independent prognostic factor. Variables relating to treatment entered the model, suggesting that chemotherapy could play an important role in determining outcome.

Adolescent↗
PubMed1995

Natural fluorescence of normal and neoplastic human colon: a comprehensive "ex vivo" study.

BACKGROUND AND OBJECTIVE: A microspectrofluorometric analysis on "ex vivo" samples from normal tissue and adenocarcinoma of the human colon has been performed to characterize the histological, biochemical, and biophysical bases of the autofluorescence. STUDY DESIGN/MATERIALS AND METHODS: Differences between normal and tumor tissues are found that concern both the intensity distribution and spectral shape of the autofluorescence emission. The different pattern of the fluorescence intensity can be related to the histological organization of the tissue, and involves mainly the arrangement of the submucosa, the most fluorescent layer. RESULTS: The most evident differences in the spectral shape found in the 480-580 nm range involve the stromal compartment, seem to be due to the presence of different fluorochromes, and are possibly related to the host response to the tumor. CONCLUSION: The nature and the extent of the autofluorescence modification between normal and tumor tissue in sections explain at least partly the evidence of the "in vivo" analysis and highlight the importance of excitation for full exploitation of the potentials of autofluorescence in diagnosis.

Adenocarcinoma↗
PubMed1994

Choroid plexus carcinoma: report of one case with favourable response to treatment.

Choroid plexus carcinoma (CPC) is a rare tumor with usually severe prognosis, whose optimal treatment has not yet been established. The exact role of complete surgical resection, chemotherapy, and radiotherapy has been debated but not clarified. We report one girl with CPC diagnosed at age 3 months and apparently cured with minimal surgical resection, chemotherapy, and delayed irradiation. At the age of 8 years, she is well, with minor psychomotor retardation and growth hormone deficiency as the only sequelae.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Brain tumours in infants. Preferred treatment options.

Since the advent of CT scan and MRI, the diagnosis of neonatal infantile brain tumours and related diseases is more easily accomplished; their rarity is reflected in the small number of cases reported. Astrocytomas and teratomas are the most common oncotypes in infants and particularly in neonates. Surgical mortality rates are not high and have decreased because of the advances of diagnosis and improvements in treatment. However, the survival rates are disappointing. Follow-up shows little improvement in last 2 decades. Adjuvant therapy is still a problem; radiotherapy gives a small percentage of favourable later neuropsychological results. Postoperative chemotherapy added to maximal surgical resection and delayed irradiation may prolong survival with only minimal short term neurotoxicity in very young children with malignant tumours. Different protocols of chemotherapy are suggested but still not definitely accepted. Radical surgery seems to have a higher chance of success in neonates than infants and remains the less aggressive means; in low grade gliomas after total removal it may be preferable to perform a second operation if the tumour recurs and withhold irradiation and chemotherapy until after 3 years of age.

Brain Neoplasms↗
PubMed1990

Turcot's syndrome with intestinal lymphoma in a child: an unusual case of triple tumor.

Turcot's syndrome, the association of brain tumor (usually glioblastoma, medullo-blastoma, or astrocytoma) and colonic polyps, is a very rare condition of which about 20 cases have been reported. It has been described only once previously with cancer in a third organ system. In this paper, we report a child affected with colonic polyposis and astrocytoma (i.e., Turcot's syndrome) associated with intestinal non-Hodgkin's lymphoma.

Adenomatous Polyposis Coli↗
PubMed1989

Growing fractures: an unusual complication of head injuries in pediatric patients.

Authors analyze three cases of growing fractures they observed in infants under the age of one year. It is noticeable that in two cases, even if the lesion was already present when babies underwent the first procedure, no specific treatment was adopted, thus resulting in a progressive enlargement of the extracranial mass. Surgical treatment must be performed quickly after the diagnosis of growing fracture is done due to the necessity of an early repair of the bone defect to avoid the eventual onset of neurological deficits since they are not reversible.

Arachnoid↗
PubMed1988

Spontaneous cerebellar hemorrhage.

Spontaneous cerebellar hemorrhage was rarely diagnosed in the past and therefore thought to be infrequent but after the introduction of CT scanning has been more commonly diagnosed. A series of 28 cases of spontaneous cerebellar hemorrhage is analyzed concluding that the radiological and clinical aspects should be considered, instead of adopting the diameter as surgical indicator. An accurate monitoring of the patient's clinical status is very important since its worsening is an absolute indication for surgery independently of the size of hematoma.

Adult↗