PubMed Health⌕ Search

Biomedical subjects

S Paolini

Publications and source records attributed to S Paolini.

At least 19 recordsLinked to original sources
PubMed2006

Surgical exposure of lateral orbital lesions using a coronal scalp flap and lateral orbitozygomatic approach: clinical experience.

BACKGROUND: The lateral extraconal compartment is a typical localization of intra-orbital tumours. With the exception of anterior lesions, which can be reached by a transconjuntival route, most of these tumours are currently approached through the classic lateral orbitotomy originally described by Kronlein. We present here our experience in the management of lateral orbital lesions, using a coronal skin flap, followed by subfascial dissection of the temporalis muscle. The procedure was intended to overcome the potential drawbacks associated with the classic transtemporal approach. METHODS: The approach was used in eleven patients harbouring bone lesions of the lateral orbital wall or intra-orbital lesion of the lateral extra-ocular compartment. The postoperative results were assessed using a simple cosmetic outcome scale, which evalutated the temporalis muscle trophism and the function of the frontotemporal branch of the facial nerve. RESULTS: All lesions were satisfactorily exposed. The subfascial dissection of the temporalis muscle is a key manoeuvre which, at the same time, abolishes the risk of injury to the frontotemporal branch of the facial nerve and provides a wide exposure of the lateral orbital wall. The cosmetic outcome was excellent in 9 patients and good in 2 patients. CONCLUSIONS: The reported technique is a convenient surgical option to approach lateral intra-orbital lesions, with a minimal cosmetic impact.

Adult↗
PubMed2006

Post-radiation intramedullary malignant peripheral nerve sheath tumor.

We report the intramedullary growth of a malignant peripheral nerve sheath tumour (MPNST). A 50year-old man developed a severe tetraparesis over a 4-month period. Following irradiation of a chronic tonsillitis during his childhood, the patient had later experienced a number of post-radiation diseases, including a laryngeal cancer that required permanent tracheotomy. Before admission, a magnetic resonance imaging (MRI) study had disclosed a C4-C5 intramedullary lesion. On admission to our Department, the patient had a nearly complete tetraparesis. At surgery, the lesion was exposed through a posterior midline myelotomy. A friable neoplasm, with no clear plane of cleavage, was found. The tumour was subtotally resected. Histological examination, which intraoperatively had not yielded a specific diagnosis, eventually revealed a MPNST, grade intermediate, with ultrastructural and immunohistochemical features consistent with a schwannian differentiation. No postoperative radiotherapy was undertaken. The patient died 9 months later from pneumonial complications. MPNSTs may develop within the spinal cord similarly to their benign schwannian counterpart. The reported sequence of events might support a possible relation between irradiation of the spinal cord and induction, followed by malignant transformation, of intramedullary schwannosis. This unique case must be added to the growing list of radiation-induced spinal cord tumours.

Cell Movement↗
PubMed2005

Cerebral vasospasm in patients with unruptured intracranial aneurysms.

Intracranial arterial vasospasm is a typical sequela of subarachnoid haemorrhage. The association between symptomatic vasospasm and unruptured aneurysms has been sporadically presented in the literature. The pathogenesis of this unusual entity is unclear. The published cases were collected in this review and analysed with regard to timing, clinical presentation and possible relationship with surgical factors. We also added an illustrative case which was recently observed in our department.

Cerebral Angiography↗
PubMed2005

Spinal subarachnoid hematomas: our experience and literature review.

STUDY DESIGN: Spinal subarachnoid hematomas are unusual and difficult to diagnose and the outcome of treatment is influenced by the lesions that frequently accompany them. OBJECTIVES: To clarify the neuroradiological diagnostic aspects of spinal subarachnoid hematoma as well as the results of treatment. BACKGROUND: Only recently has subarachnoid hematoma been clearly distinguished from more common subarachnoid hemorrhage and its characteristics have still not been dealt with in detail. METHODS: A total of 69 cases (3 personal case, 66 published cases) were revised in terms of etiology, diagnostic imaging and the results of both surgical and conservative treatment. RESULTS: The most common causes of spinal subarachnoid hematoma are coagulopathies (either pharmacologically-induced or resulting from systemic diseases) (40.5%), lumbar puncture for diagnostic or anesthesiological purposes (44.9%) and traumatic injuries (15.9%): these factors may be present singly or variously combined. They may be spontaneous (17.3%) or, in rare cases, associated with aortic coarctation or degenerative vascular diseases. Overall mortality is 25.7%. In the 50 cases in whom long-term follow-up was possible, the outcome of treatment, which is almost exclusively always surgical, was good in 93.5% of 31 patients in whom neurological status on admission was satisfactory and in 15.8% of 19 cases with severe neurological deficits. CONCLUSIONS: MRI and CT are not usually diagnostic because they are not able to differentiate between a subarachnoid lesion and a subdural one. However, diagnosis may be possible when these investigations detect the CSF or the contrast medium surrounding the hematoma. Although the risks of producing spinal subarachnoid hematoma as a result of LP are remote, this is, in fact, the primary cause in patients with coagulopathies. The results of treatment depend on the patient's initial neurological condition, the severity of any concomitant pathologies, the position of the hematoma and the eventual association of a subdural hematoma.

Aged↗
PubMed2005

Cerebral Whipple's disease as a cause of reversible dementia.

We describe a case of reversible dementia caused by Tropheryma whippelii (TW). Diagnosis was confirmed by a positive polymerase chain reaction for this pathogen both on serum and cerebrospinal fluid. Specific antibiotic therapy resulted in distinct clinical and neuroradiological improvement. Control polymerase chain reaction for T. whippelii on serum and cerebrospinal fluid was negative.

Aged↗
PubMed2005

Spinous process marking: a reliable method for preoperative surface localization of intradural lesions of the high thoracic spine.

Surgical exposure of intradural lesions in the thoracic spine requires intraoperative landmarks to identify the vertebral level. If spinal neuronavigation is not available, the surgeon must rely on alternative localizing methods. Intraoperative fluoroscopy is traditionally used to count the vertebrae throughout the whole spine. In the high thoracic spine, counting the vertebrae is often hampered by the scapular shadows. In these cases, a preoperative marking procedure seems preferable. Magnetic resonance imaging (MRI) based techniques have been increasingly reported, but they share an intrinsic risk of error due to the skin shift occurring at the time of surgery. We describe here a simple technique for unequivocal identification of the vertebral target. In six patients undergoing surgery for intradural lesions of the high thoracic spine, the spinous process of the vertebra corresponding to the lesion was preoperatively identified on an anteroposterior radiograph view and marked infiltrating its tip with a blue dye. At surgery, the vertebral target was identified easily and immediately. No errors occurred. No complications related to the technique were observed. Preoperative marking of the vertebral spinous process with a coloured dye is a simple and unequivocal guide to expose intradural lesions in the high thoracic spine.

Coloring Agents↗
PubMed2003

Ethylene oxide sterilization of autologous bone flaps following decompressive craniectomy.

INTRODUCTION: In patients undergoing decompressive craniectomy, the bone flap is temporarily preserved either in the subcutaneous tissue of the patient or frozen. However, there are some drawbacks related to these methods. MATERIAL AND METHODS: In 16 patients in whom the bone flap was removed for decompressive craniectomy, the bone was firstly washed in hydrogen peroxide and then placed in hermetically-sealed bags and sterilized using ethylene oxide. The bone was repositioned after an average period of 4.3 months. RESULTS: One patient sustained an infection of the surgical wound which required permanent exclusion of the bone flap. In all the others, esthetic and functional results were good after an average follow-up of 20 months. Control CT-scan of the bone flap demonstrated preservation of its structural features with fusion of the bone margins and revitalization of the flap. On MRI a subdural space was again visible. CONCLUSIONS: Sterilization of the bone flap with ethylene oxide in patients undergoing decompressive craniectomy avoids some of the drawbacks related to the techniques currently used. The easiness, low cost, good aesthetic and functional results of this procedure make it a valid alternative to other techniques for preservation of autologous bone in decompressive craniectomies.

Adult↗
PubMed2003

Postpartum cerebral ischaemia after accidental dural puncture and epidural blood patch.

Puerperal women are reported to have a rate of cerebral infarction 13 times greater than non-pregnant females. We report a case of cerebral ischaemia in a 30-yr-old healthy parturient after epidural analgesia for labour, complicated by dural puncture treated with two epidural blood patches. Investigations showed the development of cerebral ischaemia on postpartum day 14. A transcranial Doppler ultrasonography showed vasospasm of the left middle cerebral artery still present at 3-month follow-up. At 1-yr follow-up, the patient had homonymous hemianopsia. We discuss the possible causative mechanism of the cerebral ischaemia in relation to the dural puncture and epidural blood patch.

Adult↗
PubMed2003

Pericranial flap fixation using titanium miniplates and screws.

Opening the frontal sinuses is a common occurrence during neurosurgical procedures involving the anterior cranial base. Obliteration of the exposed sinuses is usually accomplished packing them with various materials and/or covering them with an anteriorly-based pericranial flap. In the absence of more extensive cranial base defects, the flap only needs to be wrapped around the sinus and secured against its posterior wall. We describe the technique for and the results of using titanium miniplates and screws to secure the pericranial flap to the inner surface of the frontal bone. In 10 patients treated with this alternative technique, the pericranial flap provided an excellent separation between the sinuses and the intradural compartment. No cases of cerebrospinal fluid leakage or infections were observed.

Bone Plates↗
PubMed2002

Discontinuous myelotomy: an alternative to standard myelotomy in the surgical treatment of intramedullary spinal cord tumours.

BACKGROUND: Myelotomy is an essential step for the removal of intramedullary tumours. Often, this manoeuvre requires division of large vessels surfacing the midline, contributing to the development of postoperative sensory deficits. We developed a technique of discontinuous myelotomy to preserve the integrity of these large spinal cord vessels. METHODS: Over a three-year period, we approached 20 intramedullary astrocytomas through a posterior myelotomy consisting of two separate incisions one above and the other below the midline vessel. The tumour was removed using the Cavitron ultrasound aspirator (CUSA), through either incision. Tumour underlying the bridging area between the two incisions was successfully removed through an oblique view. FINDINGS: We retrospectively analysed the clinical outcome in terms of sensory function. Follow-up examinations showed that up to 70% of the patients had their sensory function unchaged. 5 (20%) patients experienced a permanent worsening of their deficits, involving superficial and deep sensation in cases 1 and 4, respectively. Two (10%) patients showed significant improvement. INTERPRETATION: Discontinuous myelotomy is a viable technical option whenever the presence of large vessels on the median raphe would make the standard midline myelotomy unsafe.

Astrocytoma↗
PubMed2002

Atypical tentorial meningioma 30 years after radiotherapy for a pituitary adenoma.

Although the human central nervous system used to be considered relatively resistant to the carcinogenic action of ionizing radiation, several lines of evidence now document a high incidence of secondary tumors in irradiated patients. The numerous reports of radiation-induced cerebral meningiomas generally distinguish those induced by high-dose radiation from those induced by low-dose radiation. We describe the case of patient who underwent subtotal resection of a chromophobe pituitary adenoma at the age of 18 years, who was successively treated by conventional fractionated radiotherapy with gamma rays emitted by a source of 60Co until a total dose of 41 Gy. Over the next 30 years the patient experienced all the known late effects of radiation, including panhypopituitarism, cranial-nerve deficits (II, III and VI), massive radiation necrosis involving the left cerebral hemisphere and causing right hemiparesis and aphasia and, ultimately, an atypical tentorial meningioma with early recurrence after total resection.

Adenoma, Chromophobe↗
PubMed2002

Dose-dependent inhibition of mitochondrial ATP synthase by 17 beta-estradiol.

Mitochondria produce energy through oxidative phosphorylation. A key enzyme in this pathway is F0F1-ATP synthase, catalyzing ATP production from ADP and inorganic phosphate. Recently a subunit of F0F1-ATP synthase, oligomycin sensitivity-conferring protein, was identified as a new estradiol-binding protein. Estradiol could directly modulate mitochondrial ATP synthase activity through this subunit. In addition, intracellular ATP levels play a role in apoptotic death, which is an energy-dependent process requiring functioning mitochondria. Here we examined the effect of 17 beta-estradiol on F0F1-ATP synthase directly (in permeabilized cells) and in intact osteoclastic FLG 29.1 cells, a model of inducible apoptosis. The baseline F0F1-ATP synthase activity of FLG 29.1 cells was 4.485 nmol/min per mg. Estradiol rapidly inhibited F0F1-ATP synthase activity in the physiological range (half-inhibition concentration, IC50, of 30 nmol/l). With 1 nmol/l of estradiol, the inhibition was already significant (8-10% inhibition, p < 0.01) and with 100 nmol/l residual enzyme activity was only 15% (85% inhibition, p < 0.01). In addition, the effect of estradiol appeared to be directed towards F0F1-ATP synthase, since succinate-sustained respiration, uncoupled from the electron transport chain, was unaffected by estradiol. We assayed F0F1-ATP synthase activity in FLG 29.1 cells during inducible apoptosis. No significant difference of ATP synthesis was detected in apoptotic cells versus controls. In conclusion, we showed a new non-genomic effect of estradiol on a key mitochondrial enzyme, which thereby directly modulates cellular energy metabolism.

Adenosine Triphosphate↗
PubMed2001

Purification, cloning and characterisation of odorant- and pheromone-binding proteins from pig nasal epithelium.

Two distinct classes of lipocalin isoforms (OBP-IIs and OBP-IIIs) were purified and identified from porcine nasal mucosa of male and female individuals. Using primers designed on their N-terminal sequence, the complete primary structures of the mature polypeptides were determined. Mass spectrometry analysis confirmed the identity of the cDNA-derived sequences and provided information regarding their post-translational modifications. These species strongly resemble a lipocalin expressed by von Ebner's gland and salivary lipocalins carrying sex-specific pheromones secreted only by the boar's submaxillary glands. Both OBP-IIs and OBP-IIIs present two cysteines paired in a disulphide bond; the remaining residues occur in a reduced form. In addition, OBP-IIIs are heavily glycosylated and markedly different in their glycan moiety from the salivary lipocalins. A three-dimensional model is proposed based on protein species with known structure. Like salivary lipocalins, OBP-IIIs bind a number of odorant molecules, with highest affinity for the specific pheromone 5alpha-androst-16-en-3-one. The high similarity between OBPs from the nasal area and lipocalins from secretory glands suggests a common function in binding the same pheromonal ligands, the latter carrying chemical messages into the environment the former delivering them to specific receptors.

Amino Acid Sequence↗
PubMed2000

Cloning, post-translational modifications, heterologous expression and ligand-binding of boar salivary lipocalin.

Boar submaxillary glands produce the sex-specific salivary lipocalin (SAL), which binds steroidal sex pheromones as endogenous ligands. The cDNA encoding SAL was cloned and sequenced. From a single individual, two protein isoforms, differing in three amino acid residues, were purified and structurally characterized by a combined Edman degradation/MS approach. These experiments ascertained that the mature polypeptide is composed of 168 amino acid residues, that one of the three putative glycosylation sites is post-translationally modified and the structure of the bound glycosidic moieties. Two of the cysteine residues are paired together in a disulphide bridge, whereas the remaining two occur as free thiols. SAL bears sequence similarity to other lipocalins; on this basis, a three-dimensional model of the protein has been built. A SAL isoform was expressed in Escherichia coli in good yields. Protein chemistry and CD experiments verified that the recombinant product shows the same redox state at the cysteine residues and that the same conformation is observed as in the natural protein, thus suggesting similar folding. Binding experiments on natural and recombinant SAL were performed with the fluorescent probe 1-aminoanthracene, which was efficiently displaced by the steroidal sex pheromone, as well as by several odorants.

Amino Acid Sequence↗
PubMed2000

Mass spectrometry study of ecto-5'-nucleotidase from bull seminal plasma.

The structure of ecto-5'-nucleotidase from bull seminal plasma, containing a glycosyl-phosphatidylinositol anchor, was studied using mass spectrometry. MALDI-MS analysis of intact protein indicated a mass of 65 568.2 Da for the monomeric form, and it also showed a heterogeneous population of glycoforms with the glycosidic moiety accounting for approximately 6000 Da. MALDI-MS analysis showed that Asn53, Asn311, Asn333 and Asn403 were four sites of N-glycosylation. GC-MS analysis provided information on the glycosidic structures linked to the four asparagines. Asn53, Asn311 and Asn333 were linked to high-mannose saccharide chains, whereas the glycan chains linked to Asn403 contained a heterogeneous mixture of oligosaccharides, the high-mannose type structure being the most abundant and hybrid or complex type glycans being minor components. By combining enzymatic and/or chemical hydrolysis with GC-MS analysis, detailed characterization of the glycosyl-phpsphatidylinositol anchor was obtained. MALDI spectral analysis indicated that the glycosyl-phosphatidylinositol core contained EtN(P)Man3GlcNH2-myo-inositol(P)-glycerol, principally modified by stearoyl and palmitoyl residues or by stearoyl and myristoyl residues to a minor extent. Moreover, 1-palmitoylglycerol and 1-stearoylglycerol outweighed 2-palmitoylglycerol and 2-stearoylglycerol. The combination of chemical and enzymatic digestions of the protein with the mass spectral analysis yielded a complete pattern of S-S bridges. The protein does not contain free thiols and its eight cysteines are linked by intramolecular disulfide bonds, the pairs being: Cys51-Cys57, Cys353-Cys358, Cys365-Cys387 and Cys476-Cys479. This work resolves details of the structure of ecto-5'-nucleotidase, with particular regard to the localization and composition of the glycidic moiety, number and localization of the disulfide bridges and characterization of the glycosyl-phosphatidylinositol anchor.

5'-Nucleotidase↗
PubMed2000

Radiation injury involving the internal carotid artery. Report of two cases.

Radiation therapy is an uncommon cause of stenosis and occlusions of the cervical internal carotid artery (ICA). We describe two cases of cerebral ischemia due to ICA stenosis in patients irradiated for malignant tumors (lymphoma and breast cancer). The first patient, a 32-year-old man, presented with an episode of cerebral ischemia. Six years previously he had received irradiation therapy for a left laterocervical mass histologically diagnosed at biopsy as a Hodgkin's lymphoma. Cerebral angiography on entry revealed bilateral occlusion of the cervical ICA, with a 2-cm stump at the origin of the left ICA. Despite anti-platelet aggregation therapy the ischemic attacks persisted, necessitating a stumpectomy. After vascular-repair surgery the patient had no further ischemic symptoms. The second patient, a 42-year-old woman, began to experience the sudden onset of pain in the right arm and left hemiparesis five years after surgery plus irradiation (4500 rad) for breast cancer, and three years after excision of a single cerebral metastasis. Cerebral angiography obtained on admission showed occlusion of the right ICA and right subclavian arteries, both lesions necessitating thrombectomy. After surgery the right radial pulse immediately re-appeared and the hemiparesis regressed. In both patients, 2-year follow-up assessment by Doppler ultrasonography and magnetic resonance angiography (MRA) confirmed that the operated arteries remained patent. These two unusual cases underline the potential risk of irradiation-induced ischemic cerebrovascular symptoms, suggesting that patients who have received radiation therapy to the neck and mediastinum who survive for more than 5 years should undergo regular non-invasive imaging of neck vessels (Doppler ultrasonography and MRA).

Adult↗
PubMed1999

Porcine odorant-binding protein: structural stability and ligand affinities measured by fourier-transform infrared spectroscopy and fluorescence spectroscopy.

Infrared spectra show that the binding of the odorants 2-isobuthyl-3-methoxypyrazine (PYR) and 3,7-dimethyl-1-octanol (DMO) stabilises the tertiary structure of porcine OBP-I against thermal denaturation. The fluorescence emission spectrum of the single tryptophan shows a lambdamax at 337 nm, indicating that the residue is not directly exposed to the solvent. Tryptophan does not appear to be involved in the odorant binding process and it is not accessible to the fluorescence quenchers NaI, CsCl and acrylamide. The binding of the fluorescent dye 1-aminoanthracene (1-AMA), a strong ligand, does not modify the tryptophan fluorescence spectrum. In contrast, the lambdamax of 1-AMA bound to OBP-I is shifted from 537 to 481 nm, with a lambdamax intensity increase by a factor of 80. Bound 1-AMA is displaced by odorant molecules in competitive binding assays and can be employed in simple and rapid binding assay, avoiding the use of radioactive ligands. The Scatchard plot shows that 1-AMA binds to OBP-I with a dissociation constant of 1.3 microM and an equimolar stoichiometry.

Animals↗