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Biomedical subjects

L Pellettieri

Publications and source records attributed to L Pellettieri.

At least 19 recordsLinked to original sources
PubMed2004

Fractionated, stereotactic proton beam treatment of cerebral arteriovenous malformations.

OBJECTIVES: To evaluate the therapeutic efficiency and adverse effects of stereotactic proton beam treatment of cerebral arteriovenous malformations (AVM). MATERIAL AND METHODS: Twenty-six patients treated in Uppsala during 1991-97 were included (men = 14, women = 12; mean age = 39, range = 23-64). The nidus volumes ranged from 0.3 to 102 ml (mean = 24, median = 13). The follow-up included clinical evaluation, magnetic resonance imaging (and/or computed tomography) every 6-12 months for 3 years and final angiography. RESULTS: The volume changes at final follow-up in AVMs >25 ml were -89, -85, -44, -29, -7, 0, 0, +5 and +18 (%); in AVMs 11-24 ml, -100, -100, -97, -92 and 0 (%); and in AVMs <10 ml, -100, -100, -100, -100, -100, -99, -98, -50, -0 and +40 (%). Two patients were lost to follow-up due to cerebral haemorrhage and myocardial infarction. Radiology displayed significant perifocal oedema in one patient and slight oedema in four patients. Of nine patients with epilepsy, seven became seizure-free after therapy while two continued to suffer from seizures. CONCLUSION: Proton beam irradiation is successful in a relatively high proportion of intermediate and large-sized cerebral AVMs. The adverse effects are acceptable. The advantage of proton treatment compared with gamma knife and LINAC stereotactic irradiation is that protons can irradiate even large volumes with a very sharp dose profile against normal surroundings. Thus, proton beam irradiation is a valuable option in the treatment of AVMs larger than 10 ml.

Adult↗
PubMed1999

Stereotactic irradiation of skull base meningiomas with high energy protons.

Nineteen patients with inextirpable skull base meningioma with involvement of neurovascular structures were given irradiation with a 180 MeV proton beam at the The Svedberg Laboratory, Uppsala, Sweden. The patients were treated seated in a fixed position with a stereotactic approach. Titanium-markers to the outer table served for identification and verification of the target positioning for dose planning and irradiation. The patients were given a total dose of 24 Gy in four consecutive daily 6 Gy fractions. All patients have been followed for at least 36 months. So far no meningiomas have progressed after treatment. Two patients have developed corticosteroid responsive oedema in the target area 6 moths after treatment. Late, but not serious, symptoms of side effects have been observed in one patient.

Adult↗
PubMed1999

Differences in radiosensitivity between brain, small and large arteriovenous malformations. A tentative explanation of the incongruent results of radiotherapy.

Intriguing differences in the results of brain arteriovenous malformation (AVM) therapy with ionizing radiation are reported in the literature, i.e. AVMs obliterate at different time intervals from the initiation of radiotherapy although presenting with similar nidus volumes that are treated with the same radiation dose. The purpose of this paper is to present a new concept that explains the variety of results after radiotherapy. To account for an individual AVM's responsiveness to radiotherapy, four variables have been identified from the literature. The variables are factors that are generally accepted to influence the biological effect of radiation. Combined, they can visualize a variety of AVM tissues as well as surrounding normal brain. These hypothesized variations in the type of tissues are then matched with the incongruent results of radiotherapy in order to clarify the issue. Future clinical research programs and possible therapeutical implications of this concept are proposed and discussed.

Arteriovenous Malformations↗
PubMed1997

Hidden compartments in AVMs--a new concept.

PURPOSE: The concept of hidden compartments in cerebral arteriovenous malformations (AVMs), which is hereby launched, offers a new explanation for the neurosurgical and neuroradiological controversies concerning patients with AVMs. MATERIAL AND METHODS: Three patients who were considered completely cured of their AVMs, subsequently developed new areas of malformed vessels as revealed by later angiograms. RESULTS: These 3 cases support our hidden compartment hypothesis and are reported on here, illustrated with relevant angiograms. The clinical implications of the hidden compartment concept refer to phenomena such as AVM growth, AVM recurrence after surgical excision, irradiation or embolization as well as per- or postoperative hemorrhage and swelling. CONCLUSION: The incidence of hidden compartments in the AVM population is unknown but further studies, particularly in the realm of superselective embolization, could reveal their presence.

Adult↗
PubMed1996

Activation PET scanning in pretreatment evaluation of patients with cerebral tumours or vascular lesions in or close to the sensorimotor cortex.

Treatment of tumours and vascular lesions in or close to eloquent cortex may inflict neurological deficits. Intra-operative mapping procedures have been used for many decades in efforts to minimize neurological sequelae. The possibility for non-invasive pre-operative brain mapping has emerged with the advent of positron emission tomography (PET). In this paper we report on 11 patients with a tumour or vascular lesion in or close to the sensorimotor (10 patients) or visual cortex (one patient). The patients were subjected to activation PET scanning by means of vibrotactile or visual stimulation. The results show that in most of the patients the important relation between the lesion and the sensorimotor cortex could be determined. The patient with a lesion in the occipital lobe had involvement of the entire visual cortex as judged by comparison with activated areas on the nonlesion side.

Adult↗
PubMed1996

Warning leak and management outcome in aneurysmal subarachnoid hemorrhage.

The impact of warning leaks on management results in patients with aneurysmal subarachnoid hemorrhage (SAH) was evaluated in this prospective study. In a consecutive series of 422 patients with aneurysmal SAH, 84 patients (19.9%) had an episode suggesting a warning leak; 34 (40.5%) of these patients were seen by a physician without the condition being recognized. The warning leak occurred less than 2 weeks before a major SAH in 75% of the patients. A good outcome was experienced by 53.6% of patients who had a warning leak versus 63.3% of those who had no warning leak. In a subgroup of patients who had an interval of 3 days or less from warning leak to SAH, only 36.4% had a good outcome. The proportion of patients in good neurological condition (Hunt and Hess Grades I and II) who had a good outcome was 88.1% in the group with no warning leak versus 53.6% in the group whose SAH was preceded by a warning leak. A difference of 35% between these two groups reflects the impact of an undiagnosed warning leak on patient outcome, based on the assumption that patients with a warning leak had clinical conditions no worse than Hunt and Hess Grade II at the time of the episode. In the subgroup of patients with the short interval between warning leak and SAH, the difference was almost 52%. The difference in outcome also reflects the potential improvement in outcome that can be achieved by a correct diagnosis of the warning leak. If the correct diagnosis is made in patients seeking medical attention due to a warning leak, favorable outcomes in the overall management of aneurysmal SAH are estimated to increase by 2.8%. An active diagnostic attitude toward patients experiencing a sudden and severe headache is warranted as it offers a means of improving overall outcome in patients with SAH.

Adolescent↗
PubMed1995

The immunorejection of neoplasia in a theoretical model.

A theoretical model is presented based on the idea that the immune system of a patient with a tumour can cross-react against transplanted normal foreign cells as well as against the patient's own neoplastic cells, thereby rejecting both. This hypothesis is shown in a diagram, the potential use of which is discussed.

Antigens, Neoplasm↗
PubMed1994

Patient positioning for fractionated precision radiation treatment of targets in the head using fiducial markers.

When irradiating targets in the brain, an accurately localised dose is often needed. One crucial moment to achieve this is the positioning of the patient. We have developed a positioning method where the patient is immobilised with a bite block and a head mould, and where the position of the target is determined by X-ray imaging of fiducial markers that are placed in the patient's skull. A method for computing the transformation needed to move the target from the observed to the prescribed position and orientation is described. This method uses the information from two orthogonal X-ray images and takes measurement errors and data from three or more markers into account. Results from using the method clinically in proton beam therapy are given.

Algorithms↗
PubMed1994

Endovascular treatment of a spinal arteriovenous malformation in a 21-month-old boy.

Reports of spinal arteriovenous malformations in children are rare. This case report describes a 21-month-old boy whose first symptom was attacks of abdominal pain, followed gradually by neurological symptoms. The diagnosis was made using magnetic resonance imaging and spinal angiography, and the patient was successfully treated with embolization.

Aortography↗
PubMed1993

Cellular differentiation: a theory based on simulation with computer graphics.

Rules are outlined in order to construct graphically a computer model that deals with cell growth, multiplication and differentiation. The process starts with a multicoloured stem cell and the end product will be differentiated cells represented by different colours. Various biological processes and neoplastic transformation can also be simulated. Based on the idea that the model corresponds to real events, predictions are made about the possible results of future experiments.

Animals↗
PubMed1989

Doctors' versus patients' evaluation of results after neurosurgery.

A comparison between doctors' and patients' judgements of results after treatment for various neurosurgical conditions has been made. Ninety consecutive patients (41 women and 49 men) treated for trauma, vascular diseases, tumours, pain, and malformations were included in the study. The physicians responsible for the treatment and the patients rated the result of the therapeutic efforts (operative or nonoperative) independently from each other on a five grade scale at the time for discharge. A follow-up study was also made 8-24 months after the treatment. Three different groups of paired observations were distinguished: (1) "identical opinion", (2) "pessimistic opinion" (physician's score lower than patient's) and (3) "optimistic opinion" (physician's score higher than patient's). At the time of discharge identical opinion about the result of treatment was present in 83% (75 cases) whereas 9% (8 cases) and 8% (7 cases) were referred to the groups of pessimistic and optimistic opinions respectively. In the follow up series the corresponding values were 57%, 12%, and 31%. The increase of non-identical judgements in the follow-up study was found almost exclusively in the group of patients treated for painful conditions. Also the spread of judgements was largest in the group of painful conditions. Otherwise there was no correlation between the actual result of treatment and diagnosis, sex or age.

Attitude of Health Personnel↗
PubMed1988

Nimodipine treatment of selected good-risk patients with subarachnoid hemorrhage: no significant difference between present and historical results.

Eighty-four patients were treated early with nimodipine intravenously, and thereafter orally, up to 21 days after aneurysmal subarachnoid hemorrhage. Thirty-nine patients in the nimodipine-treated group were carefully selected to be compared with similar patients from a historical control group (114 patients) conventionally treated. The causes of poor results were clinically identified as follows: delayed ischemic deterioration (DID), rebleeding, complications of surgery, or not defined. There was no significant difference in the distribution of DID or outcome at follow-up examination (at least 6 months later) between the nimodipine-treated group and the control group.

Adolescent↗
PubMed1988

Malignant prolactinoma with multiple intracranial metastases studied with positron emission tomography.

A rare case of a patient with multiple intracranial metastases from a prolactin-secreting pituitary neoplasm is described. At the age of 14 years, the patient had been operated on for a sellar tumor; he presented 12 years later with severe headache, at which time computed tomographic and magnetic resonance imaging scans revealed multiple intracranial metastases. Histopathology examination showed pituitary neoplastic cells with positive immunostaining for prolactin. The patient was investigated with positron emission tomography (PET) and dopamine D2-receptor binding, and the amino acid metabolism of the tumor was characterized in vivo. High dopamine D2-receptor binding and high amino acid metabolism were found in the tumor. The patient was subsequently treated with bromocriptine injections that resulted in a decrease in serum prolactin levels, decreased dopamine D2-receptor binding, reduced amino acid metabolism, and a reduction in tumor volume. This case demonstrates a beneficial effect of bromocriptine treatment in a patient with prolactinoma with multiple intracranial metastases. It also illustrates the great potential of PET in the in vivo characterization of the D2-binding and the high sensitivity of 11C-labeled L-methionine in the follow-up of treatment in patients with pituitary adenomas.

Adenoma↗
PubMed1987

Prognostic evaluation before operative extirpation and radiotherapy of solitary brain metastasis.

This is a retrospective study of 134 patients operated on for solitary brain metastasis at the University Hospital in Uppsala, Sweden between 1963 and 1982. All the patients underwent postoperative radiation therapy. A statistical evaluation of different prognostic factors was made in order to create a prognostic model, a so-called risk profile, to be used for future patients. The most important factors for the making of risk profiles were found to be the "histological diagnosis" followed by the "location" in the brain, then the "state on admission" and the "age" at admission in that declining order. All these variables separately and together, i.e., as risk profiles, were matched against the outcome during survival as Karnofsky's scores and against the length of survival time. The results are shown in a diagram giving the surgeon grounds for his decision-making for or against operation and also for pre-operative information.

Age Factors↗
PubMed1987

Surgical and conservative treatment of cervical spondylotic radiculopathy and myelopathy.

One hundred and fourteen patients were admitted to our department for evaluation of their cervical spondylogenetic symptoms, including local cervical pain, radiculopathy and myelopathy. This retrospective study gives the results, expressed as improved, unchanged or worse, of anterior surgery, posterior surgery and conservative treatment. Local cervical pain improved in about half of the patients, without any difference between the groups. The effect of surgery on radiculopathy was superior to that of conservative treatment, 71 percent and 74 percent respectively, being improved after anterior and posterior surgery, compared to 19 percent in the conservatively treated group. The majority of patients with myelopathy were treated with posterior surgery and 69 percent had improved. The results were not influenced by the patients age or the duration of symptoms. It is argued that the positive effects of surgery on the radiculopathy are due to a segmental stabilisation rather then to decompression. The immediate post-operative improvement of the myelopathy is undoubtedly caused by the decompression while the long-termed improvement cannot with certainty be attributed to the operation.

Adult↗
PubMed1987

Treatment of spinal cord injuries in the thoracolumbar region.

Forty patients with spinal cord injuries in the thoracolumbar region were studied. Clinical and experimental data support the conservative approach. In some patients acute stabilisation is needed and in a few patients operative decompression may be considered. Promising experimental non-invasive techniques to improve recovery are presented, but there are no convincing clinical results so far. The authors believe that regeneration will be the key area for future research.

Early Ambulation↗
PubMed1986

Serum immunocomplexes in patients with subarachnoid hemorrhage.

Immunocomplexes (IC) in serum were analyzed in 54 patients with subarachnoid hemorrhage (SAH) from ruptured arterial aneurysms. A previous study had shown that patients with SAH and vasospasm had a significantly higher incidence of ICs in the blood than patients without vasospasm. The aim of the present study was to study how the IC content varied with time and compare this pattern with the clinical picture. Forty-two patients presented clinical or radiological signs of cerebral vasospasm during their hospital stays, whereas 12 patients showed no such signs. The patients with vasospasm had a significantly higher amount of ICs in serum than those without vasospasm. In 37 patients with vasospasm, the changes of IC content during the 1st weeks after SAH correlated well with the clinical course. Data indicated that a high IC content preceded the onset of vasospasm and a low content preceded clinical improvement. This observation supports the idea that the presence of ICs might be the cause and not the result of vasospasm.

Adult↗