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Biomedical subjects

A Alfieri

Publications and source records attributed to A Alfieri.

At least 19 recordsLinked to original sources
PubMed2006

RAS and MTHFR gene polymorphisms in a healthy exercise-trained population: association with the MTHFR (TT) genotype and a lower hemoglobin level.

The aim of this study was to determine the frequencies of ACE (I/D), AGT (M235T), AT1R (A1166C) and MTHFR (C677T) polymorphisms in a well-defined (in regards to health and nutritional status and lifestyle) population of young, healthy, exercise-trained subjects (no. 100) from the Campania region of Southern Italy. We also investigated whether there was any correlation between these polymorphisms and biochemical, hematological and hemostatic parameters in this "low-risk" population. Gene polymorphisms were analyzed with the polymerase chain reaction and restriction enzyme analysis. Allele frequencies of the genotypes examined were in Hardy-Weinberg equilibrium and agree with those reported in the Italian population. No associations were found between ACE, AGT, AT1R gene polymorphisms and anthropometric, clinical and laboratory parameters. However, the MTHFR (C677T) polymorphism was significantly associated with lower hemoglobin plasma levels in TT vs. CC + CT females (p < 0.016). This report is the first to describe the frequencies of RAS and MTHFR gene polymorphisms in young, exercise-trained volunteers from Campania and to identify an association between the MTHFR gene polymorphisms and lower hemoglobin plasma levels in young healthy females.

Adult↗
PubMed2003

Endoscopic endonasal management of invasive skull base mucocele: report of two cases.

Two cases of massive erosive skull base sphenoid mucocele are reported. Even if intra-sphenoid mucoceles are an ENT pathology, when extensive they become of neurosurgical interest. An endoscopic minimally invasive procedure was performed in both cases with an excellent outcome. Patient 1 presented with several years of retro-orbital bilateral pain and several months of purulent pharyngeal leak. CT scan and MRI imaging showed an extensive erosive intra-sphenoid mass, with peripheral contrast enhancement. Patient 2 was referred because of several months of frontal headache and decreased left visual acuity. A wide intra-sphenoid mass was evident at CT scan and MRI. This mass included an anterior compartment, hyperintense on both T (1)- and T (2)-weighted images, and a posterior part, hypointense on T (1)- and hyperintense on T (2)-weighted images. A pure endoscopic endonasal one nostril pure procedure was performed in both cases. Endoscopic technique has been shown to be an easy and minimally invasive procedure. It should be the treatment of choice in case of invasive skull base mucocele in order to avoid blind damage of vasculo-nervous structures which are not protected by the bone, extensively eroded by the lesion.

Adult↗
PubMed2003

Concurrent interferon-alpha and radiation for head and neck melanoma.

Melanoma cells are resistant to radiation in part due to their capacity to repair sublethal damage. A large fraction dose is therefore often utilized. However, if the tumour is located close to critical structures with modest tolerance, high fraction doses increase the risk for late complications compared with standard fractionation, but using the latter alone risks the desired outcome. Concurrent systemic biotherapy with standard radiation fractions may therefore represent an acceptable compromise. The outcome of concurrent systemic interferon-alpha (IFNalpha) and radiation in three patients with head and neck melanoma was evaluated. Standard radiation fractions were used because of the radiosensitizing properties of IFNalpha. Acute toxicity was significant and required treatment interruptions. However, all side effects subsided following treatment. All three patients achieved local control at follow-up periods of 24, 18 and 19 months, respectively. One patient developed widespread distant metastases. The combination of IFNalpha with radiation is considered feasible in terms of outcome and should be investigated with a larger cohort of patients. Toxicity is significant, and the addition of radioprotectors could be desirable.

Aged↗
PubMed2002

Endoscopic endonasal approach to the ventral cranio-cervical junction: anatomical study.

OBJECTIVE: In order to develop an endoscopic endonasal approach to the ventral cranio-cervical junction and odontoid process under the concept of a minimally invasive surgical strategy, a cadaver study was performed. METHODS: Sixteen artery-injected adult head specimens were used. Endonasal endoscopic approach was made through one- or two-nostril routes following the Jho's endonasal paraseptal technique. Rod-lens endoscopes, which were 2.7 or 4 mm in diameter, 18 cm in length with 0-, 30-, and 70-degree lenses, were used. RESULTS: Surgical landmarks leading to the craniocervical junction were the inferior margin of the middle turbinate, nasopharynx and Eustachian tube. The nasopharynx was readily identified following the inferior margin of the middle turbinate. The line drawn between the Eustachian tubes indicated the juncture between the clivus and atlas. With a midline mucosal incision, the ventral cranio-cervical junction was exposed. Odontoid resection was performed with removal of the anterior arch of the atlas. Clival resection can be performed as much rostral as required. Maneuverability of the surgical instruments was better with a two-nostril technique than with a one-nostril. Although the entire midline clivus was accessible rostrally, C-2 was the caudal limit through this endonasal route. A suturing device needed to be developed for mucosal or dural closure for live operations. CONCLUSION: This cadaver study demonstrates that an endoscopic endonasal approach to the ventral cranio-cervical junction and odontoid process can be a valid alternative to the conventional transoral approach.

Cranial Fossa, Posterior↗
PubMed2002

Endoscopic endonasal removal of an intra-suprasellar Rathke's cleft cyst: case report and surgical considerations.

An endoscopic endonasal approach was performed to remove an intra-suprasellar Rathke's cleft cyst. Rathke's cleft cyst are benign lesions, rarely diagnosed because they are often asymptomatic. To the best of our knowledge, at least 475 cases of Rathke's cleft cysts have been reported. They seem to arise from remnants of Rathke's pouch, an invagination of the stomodeum. A 52-year-old woman, complaining of bilateral frontal headaches, was operated on by using an endoscopic endonasal approach, for an intra-suprasellar tumor. The pre-operative diagnosis was non-functioning pituitary adenoma. Intra-operatively a creamy-coloured viscous tissue was found. After the removal of the cyst contents and of the capsule, the suprasellar structures were seen well. The chiasmatic cistern, the chiasm, the pituitary stalk and the pituitary gland were visualized with 0 and 30 degree endoscopes. The pathological findings showed a well-differentiated cuboidal epithelium. The diagnosis was Rathke's cleft cyst. No post-operative complications were observed. The endoscopic technique was particularly suitable in this case, both for the Rathke's cleft features and for an excellent outcome. The Rathke's cleft cyst was easily removed by suction and the cyst wall was entirely removed with curettes and pituitary punches. The hypophysis was distinguished from the cyst and was preserved. The surgical manoeuvres were all done under direct visual control. The absence of nasal packing and of breathing difficulties made comfortable the post-operative outcome. Thus, the endoscopic endonasal approach can be considered the favourite technique in case of either intra- and/or suprasellar Rathke's cleft cysts.

Central Nervous System Cysts↗
PubMed2002

Endoscopic removal of third ventricular tumors: a technical note.

OBJECT: An endoscopic surgical technique utilizing a rollable vinyl tube as a surgical corridor is described for removal of third ventricular tumors. SURGICAL TECHNIQUE: Transcortical transventricular access is made via a burr hole placed at the point which is one inch lateral from the midline at the coronal suture area. A one-cm-diameter vinyl tube is slit longitudinally, rolled like a cigarette, and tied at its ventricular end with a release tie. With image-guided stereotactic assistance, this rolled vinyl tube is inserted into the lateral ventricle near the foramen of Monro. When the release tie is untied, the vinyl tube expands to its original 10-mm-diameter tube by recoil assisted with a balloon dilatation technique. Through this tube, a rod-lens endoscope is placed to visualize the surgical target and is mounted to an endoscope holder. Surgical instruments are inserted next to the endoscope for surgical dissection. Compared to endoscopy through fixed working-channel devices, this technique allows increased flexibility for the surgeon when maneuvering surgical instruments for delicate dissection and tumor removal. Two patients with colloid cysts and one patient with an epidermoid tumor are reported as demonstrative cases. CONCLUSION: An endoscopic technique utilizing a soft vinyl tube which can be rolled into a small diameter and then unrolled to its original size by its own recoil when a release tie is removed and by balloon dilatation, is reported for removal of third ventricular tumors.

Adult↗
PubMed2002

Endoscopic glabellar approach to the anterior skull base: a technical note.

OBJECT: An endoscopic glabellar transethmoidal approach via a small nasional incision to the anterior skull base is reported as a minimally invasive neurosurgical technique. SURGICAL TECHNIQUE: A frontonasal craniotomy (2 x 2 cm in size) between the medial orbits is made via a nasional skin incision approximately 3-cm in length. An ethmoidectomy is performed in order to expose the skull base at the anterior cranial fossa. Anterior and posterior ethmoidal arteries, which provide blood-supply to the tumor, are interrupted during the ethmoidectomy. The tumor located at the anterior cranial fossa is removed under an endoscope. A rod-lens endoscope, which is 4-mm in diameter and 18-cm in length, is used. The dura mater is reconstructed with dural graft placement. The skull-base bone at the anterior cranial fossa is reconstructed with autogenous bone or a piece of titanium mesh. The ethmoidectomy site is filled with abdominal fat graft material. The craniotomy bone flap is secured with titanium microplates and screws. Two demonstrative patients are reported. The benefits of the minimally invasiveness of this surgical technique have been observed in patient recovery. CONCLUSION: An endoscopic glabellar transethmoidal approach to the anterior cranial fossa via a small nasional incision is reported with two patients with olfactory groove meningiomas.

Adult↗
PubMed2001

Effects of Motexafin gadolinium on tumor metabolism and radiation sensitivity.

PURPOSE: Experiments were undertaken to determine if metabolic changes induced by Motexafin gadolinium (Gd-Tex(+2), XCYTRIN) predict time intervals between drug and radiation wherein there is enhancement of radiation efficacy. METHODS AND MATERIALS: We evaluated the effect of Gd-Tex(+2) on tumor metabolism and on tumor growth using a mouse mammary carcinoma model and (31)P nuclear magnetic resonance (NMR) experiments. Response to therapy was evaluated based on time for the tumor to regrow to pretreatment size and also tumor doubling time. RESULTS: (31)P NMR experiments indicated that Gd-Tex(+2) effected tumor energy metabolism during the first 24 hours postadministration. A decrease in phosphocreatine was noted at 2 (p < 0.04), 6 (p < 0.006), and 24 (p < 0.001) hours post Gd-Tex(+2). A decrease in nucleoside triphosphates was noted only at 2 hours (p < 0.02), with subsequent recovery at 6 hours. Phosphocreatine in control (saline treated) tumors showed a significant decrease only at 24 hours (p < 0.01). Irradiation at 2 and 6 hours post Gd-Tex(+2) induced an enhanced effect compared to radiation alone as measured by analyzing the growth curves, maximum tumor volumes, and the time for the tumors to regrow to their initial volumes. Irradiation at 24 hours post Gd-Tex(+2) induced a modest enhancement in tumor growth delay compared to radiation alone. DISCUSSION: NMR spectroscopy may be useful for monitoring tumor metabolism after treatment with Gd-Tex(+2) and administering radiation during the time of maximal efficacy of Gd-Tex(+2).

Animals↗
PubMed2001

Liver irradiation: a potential preparative regimen for hepatocyte transplantation.

Advances in the understanding of hepatocyte engraftment and repopulation of the host liver have already led to the use of hepatocyte transplantation (HT) with some success in the treatment of inherited and acquired liver diseases. Wider application of HT is severely limited by the unavailability of large number of transplantable hepatocytes and difficulties associated with transplanting an adequate number of cells for achieving therapeutically satisfactory levels of metabolic correction. Therefore, there is a need for preparative regimens that provide a growth advantage to the transplanted (healthy) hepatocytes over the host's own (diseased) hepatocytes so that the former can repopulate the host liver. We have recently shown that when the liver of recipient rats was subjected to radiotherapy and partial hepatectomy before HT, the transplanted hepatocytes engrafted in and massively repopulated the liver, and also ameliorated the adverse clinical and histopathological changes associated with hepatic irradiation. This protocol was then used as a preparative regimen for transplanting normal hepatocytes into jaundice mutant rats (Gunn strain), which lack hepatic bilirubin-uridinediphosphoglucuronate glucuronosyltransferase and is a model of Crigler-Najjar syndrome Type I. The results showed long-term correction of the metabolic abnormality, suggesting that the transplanted hepatocytes repopulated an irradiated liver and were metabolically functional. This strategy could be useful in the treatment of various genetic, metabolic, or malignant diseases of the liver.

Animals↗
PubMed2001

Differential distribution of aldolase A and C in the human central nervous system.

We have analyzed the distribution of aldolase A and C mRNAs and proteins in various areas of the human brain using Northern blot analyses and immunohistochemistry. Aldolase A mRNA expression was higher than aldolase C mRNA expression in all areas of the brain examined. Aldolase C mRNA expression was highest in the cerebellum. Aldolase C protein was present in well-delimited regions of the CNS, and was distributed in stripes in the Purkinje cell layer of the cerebellum, in the inferior olives and in the sensory neurons of the posterior horn of the spinal cord. The novel finding of aldolase C in well-delimited cell compartments of the human cerebellum and in several other areas of the CNS lends weight to the hypothesis that this protein exerts other functions (e.g. sensory transmission) besides those characteristic of a glycolytic enzyme.

Afferent Pathways↗
PubMed2001

Endoscopic endonasal pituitary surgery: evolution of surgical technique and equipment in 150 operations.

OBJECTIVE: The evolution of the senior author's (HD Jho) surgical experience on endoscopic endonasal transsphenoidal pituitary surgery is reviewed in order to introduce a standardized surgical technique for pituitary endoscopy. METHODS: The progressive evolution of the surgical technique and the development of surgical instrumentation in transsphenoidal endoscopy is reviewed based upon the experience of more than 150 operations performed by the senior author between the years 1993 and 1998. RESULTS: An endoscope was used to assist visualization during conventional microscopic surgery in the first four cases (endoscope-assisted microsurgery). Subsequently, endonasal pituitary endoscopy was performed via a nostril. When the endonasal route was adopted, it eliminated the use of a transsphenoidal retractor. The use of vasoconstrictors and any form of nasal packing was discovered to be unnecessary. The inferior margin of the middle turbinate was such a consistent surgical landmark leading to the sella that the use of an intraoperative fluoroscopic C-arm was also eliminated. The adoption of a septal breaker, variously angled suction cannulas and suction-coagulators has made the operation cleaner, easier and faster. As experience increased, the operation time progressively shortened and mucosal trauma became minimal. The median patient hospital stay was one night and postoperative discomfort was noted to be minimal. CONCLUSIONS: The evolution of the senior author's endoscopic pituitary surgery is reported with a description of our current standardized surgical technique.

Acromegaly↗
PubMed2001

Endoscopic endonasal approaches to the cavernous sinus: surgical approaches.

OBJECTIVE: After completion of an earlier endoscopic transsphenoidal anatomic study, we studied various endoscopic transsphenoidal approaches using cadaveric specimens to develop endoscopic endonasal surgical approaches to the cavernous sinus. METHODS: Ten cavernous sinuses in five artery-injected adult cadaveric heads were studied with 0-, 30-, and 70-degree angled 4-mm rod-lens endoscopes. The extent of the surgical exposure, the skewed endoscopic anatomic view, and the maneuverability of surgical instruments through their relative operating spaces were studied after various endoscopic endonasal approaches via one nostril. RESULTS: The paraseptal approach was used between the nasal septum and the middle turbinate and provided exposure at the anteromedial portion of the cavernous sinus. The contralateral paraseptal approach rendered a slightly more medial view at the cavernous sinus than did the ipsilateral approach. This approach offered limited surgical access to the lateral vertical compartment. The middle turbinectomy approach allowed surgical access to the lateral wall of the cavernous sinus, except for the superior orbital fissure and the orbital apex. The middle meatal approach, which was made between the middle turbinate and the lateral nasal wall, revealed the entire lateral vertical compartment of the cavernous sinus, including the orbital apex and the superior orbital fissure. However, its lateral tangential surgical trajectory and the absence of dedicated surgical tools limited the surgeon's surgical maneuverability. A combination of the middle turbinectomy and middle meatal approaches increased the operating space. CONCLUSION: Various endoscopic endonasal surgical approaches to the cavernous sinus were studied using adult cadaveric head specimens.

Adult↗
PubMed2001

Endoscopic endonasal cavernous sinus surgery: an anatomic study.

OBJECTIVE: The endoscopic surgical anatomy of the cavernous sinus was studied to establish an anatomic basis for endoscopic endonasal cavernous sinus surgery. METHODS: Five adult cadaveric heads were studied with 0-, 30-, and 70-degree 4-mm rod-lens endoscopes. The posterior wall of the sphenoidal sinus was approached via a paraseptal, middle turbinectomy, or middle meatal approach. RESULTS: The posterior bony wall of the sphenoidal sinus is subdivided into five vertical compartments: midline, bilateral paramedian, and bilateral lateral. The midline vertical compartment consists of the planum sphenoidale, tuberculum sellae, sella, and clival indentation. The paramedian vertical compartment is composed of the medial third of the optic canal and the carotid artery protuberance. The lateral vertical compartment contains four bony protuberances (optic, cavernous sinus apex, maxillary, and mandibular) and three depressions (carotico-optic, ophthalmomaxillary [V1-V2], and maxillomandibular [V2-V3]). The three depressions form anatomic triangles at the lateral vertical compartment: the optic strut triangle, which is bordered by the optic nerve, carotid artery, and oculomotor nerve (IIIrd cranial nerve); the V1-V2 triangle; and the V2-V3 triangle. The internal carotid artery at the posterior wall of the sphenoidal sinus can be subdivided into two main segments: the parasellar and the paraclival. The vidian canal is a landmark that leads to the foramen lacerum, the mandibular nerve, and the pterygopalatine fossa. CONCLUSION: Endoscopic anatomy of the cavernous sinus has been studied via an endonasal route in cadaveric specimens to provide an anatomic basis for endoscopic endonasal cavernous sinus surgery.

Adult↗
PubMed2001

Single-screw fixation for acute Type II odontoid fracture.

BACKGROUND: The management of odontoid fractures is still controversial. The main current trends of treatment are conservative management with HALO immobilization, posterior surgical fixation or anterior surgical fixation. The authors report a consecutive series of 17 cases of patients with acute Type II odontoid fracture treated between November 1994 and February 2000. METHODS: Since June 1997 anterior odontoid screw fixation was performed in nine cases. The technical aspects of the internal fusion are described. RESULTS: Spinal stabilization was achieved in all patients. The postoperative neuroimaging demonstrates the successful positioning of the odontoid screw of all patients. CONCLUSIONS: The success of this treatment depends on patients' selection, attention to technical operative details and adequate follow-up. Internal screw fixation gives immediate direct fixation of the fracture, offers a high rate of fusion without requiring prolonged HALO immobilization, it gives a reduction of the cervical pain and preserves the normal mobility of C1-C2.

Adult↗
PubMed2000

Cerebrospinal fluid flow dynamics study in Chiari I malformation: implications for syrinx formation.

Cerebrospinal fluid (CSF) flow abnormalities are known to be present in Chiari I malformation and to underlie the origin and progression of associated syringomyelia. The incidence of syrinx formation, however, is variable for unknown reasons. The aim of this study was to investigate whether differences in CSF flow dynamics in patients with Chiari I malformation may account for the different clinical and radiological presentation. Presurgical and postsurgical phase-contrast magnetic resonance imaging investigations were prospectively conducted in 47 adult patients with symptomatic Chiari I malformation. Patients were divided into two groups according to the presence (32 cases) or absence (15 cases) of syrinx. Cerebrospinal fluid flow patterns were evaluated at four regions of interest: prebulbar cistern, foramen magnum, and the ventral and dorsal spinal subarachnoid spaces at the C-5 level. A temporal analysis of CSF flow waveforms was performed with measurement of cranial- and caudal-directed flow durations. All patients underwent a craniocervical decompressive procedure. Preoperatively, a prolonged caudal- directed (systolic) flow pattern was observed in patients with syringomyelia, as compared with normal control values obtained in 15 healthy volunteers. Conversely, a decreased systolic duration was observed in Chiari I patients who had malformation without syrinx. These trends were not statistically significant because of the considerable degree of overlap with the control values recorded in both groups. Additional comparison of the observed preoperative values obtained in patients with and those without syringomyelia indicated that the difference in systolic flow duration was significant at the ventral spinal subarachnoid space level (p = 0.003) and remarkable at the other levels, although not reaching statistical significance. Cerebrospinal fluid flow was minimal or absent at the foramen magnum (dorsal aspect) due to tonsillar herniation, precluding reliable quantitative measurement at this level. There was no evidence of communication between the fourth ventricle and syrinx in any case. Postoperatively, unobstructed CSF flow was recorded across the enlarged foramen magnum and into the artificial cisterna magna in all patients. A gradual restoration of near-normal flow patterns was observed in both groups. Inside the syrinx, fluid motion gradually tapered, no longer being detectable in 12 patients (37.5%) 1 year postsurgery. In patients with Chiari I malformation and associated syringomyelia different CSF flow patterns were demonstrated as compared with patients in whom syrinx was absent. Analysis of this study's findings supports the hypothesis that in Chiari I malformation an elongated systolic flow may prolong the condition of increased spinal subarachnoid pressure caused by the junctional obstruction, thus favoring CSF penetration into the spinal cord. It may be also proposed that a shortened systolic flow may be insufficient to maintain a hypertensive condition for enough time to induce syrinx formation.

Adult↗
PubMed2000

Post-operative monitoring of cortical taurine in patients with subarachnoid hemorrhage: a microdialysis study.

Intracerebral MD enables the retrieval of endogenous substances from the extracellular fluid (ECF) of the brain and has been demonstrated to be a sensitive technique for early detection of subtle vasospasm-induced neurometabolic abnormalities in patients with subarachnoid hemorrhage (SAH). The aim of this study was to monitor cortical extracellular concentrations of energy metabolism markers, such as glucose and lactate, neurotransmitter amino acids, such as glutamate, aspartate, GABA and taurine to identify any neurochemical patterns of cerebral ischemia. A prospective clinical study was conducted on a group of 16 patients with non-severe SAH operated on within 72 hours after initial bleeding. Following aneurysm clipping, an MD catheter was inserted in the cortical region where vasospasm could be expected to develop, and perfused with artificial CSF at 0.3 microl/min flow rate. Dialysate was collected every 6 hours and then analyzed on High Performance Liquid Cromatography (HPLC) for glucose, lactate, pyruvate, glutamate, aspartate, GABA and taurine. Mean ECF taurine concentrations ranged from 1.4 + 0.7 to 12.3 + 7.8 micromol/l in single patients: global mean value was 5.8 + 3.8 micromol/l. In this series, the highest absolute taurine value was 25.7 micromol/l, observed in a patient who developed clinical and radiological signs of cerebral ischemia. Nine patients presented clinical disturbances related to cerebral vasospasm. In this setting, representing a mild-to-moderate hypoxic condition, MD data demonstrated that lactate is the most sensitive marker of cellular energy imbalance. Increased lactate levels positively correlated with glutamate (P<0.0001), aspartate (P<0.0001), GABA (P<0.0001) and taurine (P<0.0001) concentrations. These results suggest that also in humans increased taurine levels reflect a condition of cellular stress. This study confirms that MD is a sensitive technique to reveal subtle metabolic abnormalities possibly resulting in cell damage.

Adult↗
PubMed2000

Adenovirus-mediated antisense ATM gene transfer sensitizes prostate cancer cells to radiation.

Treatment failure after radiation therapy of prostate cancer (PC) could be a significant problem. Our objective is to design genetic radiosensitizing strategies for the treatment of PC. Cells from individuals with the genetic disorder ataxia telangiectasia (AT) are hypersensitive to ionizing radiation. Therefore, we examined whether attenuation of the AT gene product, AT mutated (ATM), in PC cells could result in an increased intrinsic radiosensitivity. A p53-mutant PC cell line, PC-3 was infected with adenoviral vectors, expressing antisense ATM RNA to various domains of the ATM gene. Immunoblot analyses of cellular extracts from antisense ATM-transfected PC-3 cells showed attenuated expression of the ATM protein within 2 days of viral infection. Compared with cells infected with an adeno-beta-galactosidase vector, antisense ATM-transfected PC-3 cells showed aberrant control of S-phase cell-cycle checkpoints after exposure to ionizing radiation. Under these conditions, the intrinsic radiosensitivity of the PC-3 cells was enhanced. Consequently antisense ATM gene therapy could serve as a paradigm for strategies that target the cellular survival mechanisms of an irradiated tumor cell and may provide therapeutic benefit to patients undergoing radiation therapy for PC.

Adenoviridae↗