Biomedical subjects

P Gallina

Publications and source records attributed to P Gallina.

13 recordsLinked to original sources

PubMed2003

Neuronavigation accuracy dependence on CT and MR imaging parameters: a phantom-based study.

Clinical benefits from neuronavigation are well established. However, the complexity of its technical environment requires a careful evaluation of different types of errors. In this work, a detailed phantom study which investigates the accuracy in a neuronavigation procedure is presented. The dependence on many different imaging parameters, such as field of view, slice thickness and different kind of sequences (sequential and spiral for CT, T1-weighted and T2-weighted for MRI), is quantified. Moreover, data based on CT images are compared to those based on MR images, taking into account MRI distortion. Finally, the contributions to global accuracy coming from image acquisition, registration and navigation itself are discussed. Results demonstrate the importance of imaging accuracy. Procedures based on CT proved to be more accurate than procedures based on MRI. In the former, values from 2 to 2.5 mm are obtained for 95% fractiles of cumulative distribution of Euclidean distances between the intended target and the reached one while, in the latter, the measured values range from 3 to 4 mm. The absence of imaging distortion proved to be crucial for registration accuracy in MR-based procedures.

Algorithms↗

PubMed2003

Hypertriglyceridemia is associated with increased insulin resistance in subjects with normal glucose tolerance: evaluation in a large cohort of subjects assessed with the 1999 World Health Organization criteria for the classification of diabetes.

The current study retrospectively examined the association between insulin resistance and plasma triglycerides (TG) in a group of subjects with normal glucose tolerance. Among 1,434 subjects consecutively undergoing a standard oral glucose tolerance test (OGTT) between 1993 and 1998, 567 (age, 15 to 78 years) were classified as having a normal glucose tolerance according to the 1999 World Health Organization (WHO) criteria and were selected for the study. Serum insulin was measured by radioimmunoassay (INSI-CTK, Dia Sorin, Saluggia, Italy). Intra-assay and interassay coefficients of variation for the method were less than 4% and less than 8.5%, respectively. Insulin resistance was calculated by a homeostasis model assessment (HOMA(IR) = fasting serum insulin [mU/mL] x fasting blood glucose [mmol/L]/22.5). A very significant correlation was found between HOMA(IR) and plasma TG (r = 0.27, P < 1.02E(-10)). Multiple regression analyses confirmed plasma TG as independent variables explicative of HOMA(IR). When subjects were evaluated according to tertiles of TG, those in the upper two tertiles were older (P <.001) and presented higher body mass index (BMI) values (P <.0001) in comparison to subjects in the lower tertile. A positive trend (analysis of variance [ANOVA]) was found in regard to systolic (P <.05) and diastolic blood pressure (P <.0001), fasting blood glucose (P <.01), fasting serum insulin (P <.0001), and total cholesterol (P <.0001), while a negative trend was found in regard to high-density lipoprotein cholesterol (HDL-C) (P <.0001). Insulin resistance, calculated as HOMA(IR), was higher in the upper two tertiles of TG in comparison to the lower tertile (P <.001 and P <.0001, respectively), with a statistically significant trend for the entire group (first tertile, 1.85 +/- 0.94; second tertile, 2.28 +/- 1.10; third tertile, 2.65 +/- 1.71; ANOVA: P <.0001). In conclusion, this study shows an association between high levels of circulating TG and insulin resistance in patients with normal glucose tolerance seen in an atherosclerosis prevention clinic. This association is also present at levels of plasma TG considered to be normal and is associated with a cluster of cardiovascular risk factors.

Adult↗

PubMed2003

[Atypical, aplastic, and unusual meningiomas. Morphology and incidence in 300 consecutive cases].

We morphologically studied 300 consecutive and primitive meningiomas surgically treated between march 1997 and april 2002 in order to evaluate the incidence of atypical, anaplastic, and morphologically unusual meningiomas. Two hundred and fifty-five meningiomas (85%) were WHO I, 33 (11%) were WHO II, 9 (3%) were WHO III; the remaining 3 meningiomas (1%) showed clear and diffuse oncocytic differentiation without cytologic or architectural atypia (oncocytic meningiomas). Forty-five of 255 WHO I meningiomas (18%) were infrequent histological subtypes: 18 (7%) psammomatous, 9 (4%) metaplastic, 9 (4%) secretory, 6 (2%) angiomatous, and 3 (1%) microcystic. Thirty of 33 WHO II meningiomas (91%) were atypical, 2 (6%) were clear cell meningiomas, and 1 (3%) was chordoid meningioma. Seven of 9 WHO III meningiomas (78%) were anaplastic and 2 (22%) were papillary. We evidenced the high morphological variability and the discrete occurrence of WHO I and WHO II meningiomas.

Humans↗

PubMed2001

[Retrospective analysis of failures in radiosurgery treatment of cerebral arteriovenous malformations].

The aim of this paper is to analyze retrospectively the reasons for the failure in cerebral arteriovenous malformations radiosurgery. Several factors are evoked and discussed mainly: inaccurate target, intentional partial irradiation, repermeabilization of a previously embolized cerebral arteriovenous malformation. The results suggest the necessity of a complete irradiation of the nidus. The strategy of partial volume irradiation should be avoided, even if it necessitates lowering of the doses in large cerebral arteriovenous malformations. Accuracy in the target determination is required and a complete stereoangiography is necessary.

Adolescent↗

PubMed2000

Genomewide search for type 2 diabetes-susceptibility genes in French whites: evidence for a novel susceptibility locus for early-onset diabetes on chromosome 3q27-qter and independent replication of a type 2-diabetes locus on chromosome 1q21-q24.

Despite recent advances in the molecular genetics of type 2 diabetes, the majority of susceptibility genes in humans remain to be identified. We therefore conducted a 10-cM genomewide search (401 microsatellite markers) for type 2 diabetes-related traits in 637 members of 143 French pedigrees ascertained through multiple diabetic siblings, to map such genes in the white population. Nonparametric two-point and multipoint linkage analyzes-using the MAPMAKER-SIBS (MLS) and MAXIMUM-BINOMIAL-LIKELIHOOD (MLB) programs for autosomal markers and the ASPEX program for chromosome X markers-were performed with six diabetic phenotypes: diabetes and diabetes or glucose intolerance (GI), as well as with each of the two phenotypes associated with normal body weight (body-mass index<27 kg/m(2)) or early age at diagnosis (<45 years). In a second step, high-resolution genetic mapping ( approximately 2 cM) was performed in regions on chromosomes 1 and 3 loci showing the strongest linkage to diabetic traits. We found evidence for linkage with diabetes or GI diagnosed at age <45 years in 92 affected sib pairs from 55 families at the D3S1580 locus on chromosome 3q27-qter using MAPMAKER-SIBS (MLS = 4.67, P=.000004), supported by the MLB statistic (MLB-LOD=3.43, P=.00003). We also found suggestive linkage between the lean diabetic status and markers APOA2-D1S484 (MLS = 3. 04, P=.00018; MLB-LOD=2.99, P=.00010) on chromosome 1q21-q24. Several other chromosomal regions showed indication of linkage with diabetic traits, including markers on chromosome 2p21-p16, 10q26, 20p, and 20q. These results (a) showed evidence for a novel susceptibility locus for type 2 diabetes in French whites on chromosome 3q27-qter and (b) confirmed the previously reported diabetes-susceptibility locus on chromosome 1q21-q24. Saturation on both chromosomes narrowed the regions of interest down to an interval of <7 cM.

Age of Onset↗

PubMed2000

Effects of vitamin E supplementation on F(2)-isoprostane and thromboxane biosynthesis in healthy cigarette smokers.

BACKGROUND: Increased formation of 8-iso-prostaglandin (PG) F(2alpha) and thromboxane (TX) A(2), potent agonists of platelet and vascular thromboxane (TH)/PGH(2) receptors, has been detected in cigarette smokers. We performed a randomized, double-blind, placebo-controlled study of the effects of vitamin E (300, 600, and 1200 mg/d, each dose for 3 consecutive weeks) on 8-iso-PGF(2alpha) and TXA(2) biosynthesis in 46 moderate cigarette smokers. METHODS AND RESULTS: Urinary immunoreactive 8-iso-PGF(2alpha) and 11-dehydro-TXB(2), plasma vitamin E, and serum TXB(2) were measured by previously validated techniques. Baseline urinary 8-iso-PGF(2alpha) and 11-dehydro-TXB(2) excretion averaged 241+/-78 and 430+/-293 pg/mg creatinine, respectively. Urinary 8-iso-PGF(2alpha) was significantly correlated with 11-dehydro-TXB(2) (r=0.360, n=138, P<0.0001). Baseline plasma vitamin E levels averaged 20.6+/-4.9 micromol/L and were inversely correlated with urinary 11-dehydro-TXB(2) (r=-0.304, P=0.039) but not with 8-iso-PGF(2alpha) (r=-0.227, P=0.129). Vitamin E supplementation caused a dose-dependent increase in its plasma levels that reached a plateau at 600 mg (42.3+/-11.2 micromol/L, P<0. 001). This was not associated with any statistically significant change in urinary 8-iso-PGF(2alpha) or 11-dehydro-TXB(2) excretion. CONCLUSIONS: Supplementation with pharmacological doses of vitamin E has no detectable effects on lipid peroxidation and thromboxane biosynthesis in vivo in healthy subjects with a mild degree of oxidant stress. These findings are consistent with the hypothesis that the basal rate of lipid peroxidation is a major determinant of the response to vitamin E supplementation and have implications for the use of vitamin E in healthy subjects as well as for the design and interpretation of clinical trials of antioxidant intervention.

Adult↗

PubMed2000

Linkage and association studies between the proopiomelanocortin (POMC) gene and obesity in caucasian families.

AIMS/HYPOTHESIS: The region 2p21-23, containing the proopiomelanocortin gene (POMC), was reported to be linked to leptin concentrations in Mexican-American, French and African-American cohorts. A polyhormone peptide, POMC is expressed in brain, gut, placenta and pancreas. The POMC mutations are responsible for rare cases of early-onset obesity. Thus we examined the contribution of the POMC locus to obesity in French families. METHODS: Single and multipoint linkage studies were done between obesity, obesity associated-phenotypes (leptin values and z-score of the body mass index) and three newly mapped markers surrounding POMC in 264 affected sib-pairs from French obese families. Mutation screening of the exons and intron/exon junctions of the POMC gene was realised by direct sequencing. Association studies were done in 379 unrelated obese patients and 370 non-obese non-diabetic subjects. RESULTS: Linkage analysis confirmed the trend towards linkage between polymorphic markers around POMC and variations of leptin concentrations and z-score (maximum lod score at D2S2337 = 2.03). Mutation screening of the POMC gene in the French Caucasian cohort identified two previously reported polymorphisms. None of these variants was associated with obesity, diabetes or serum leptin and lipid concentrations. CONCLUSION/INTERPRETATION: Our results indicate that mutations in the POMC gene do not contribute to the variance of obesity associated phenotypes, at least in French Caucasians. Given the replicated evidence of linkage between leptin values and the chromosome 2p21-23 region in different populations, it is likely that functional variant(s) in the POMC regulating sequences or in an unknown gene in this region explains this linkage.

Body Mass Index↗

PubMed1998

Failure in radiosurgery treatment of cerebral arteriovenous malformations.

OBJECTIVE: The aim of this study was to retrospectively analyze the reasons for the failure of radiosurgical treatment of cerebral arteriovenous malformations (AVMs). METHODS: Seventeen cases of noncured AVMs were reviewed 3 years after radiosurgical treatment. Follow-up ranged from 33 to 54 months (mean, 44.3 mo). Lesion dimensions varied from 9 to 55 mm (mean, 29.2 mm). The lesions were located in critical or near-critical brain regions. Angiography was performed under Talairach's stereotactic conditions. Two large AVMs bled 36 and 39 months after receiving irradiation, respectively. These two AVMs had been incompletely irradiated. RESULTS: Retrospectively, in four cases (23.5%) we observed errors in determining AVM target shape and size because of inaccurate definition of the nidus and/or because of stereoangiographic incompleteness (absence of external carotid artery injections). In five large and/or irregularly shaped AVMs (29.4%), a strategy of partial volume irradiation had been used. In one patient (5.8%), we observed the recanalization of previously embolized AVMs. In another case (5.8%), the target had been partially missed. The AVMs in one case (5.8%) had been treated with an ineffective peripheral dose. In one (5.8%), the failure occurred because of the lesion angio-architecture. In four cases (23.5%), no evident reasons for failure were determined. CONCLUSION: The results of this study suggest the necessity of complete irradiation of the nidus. The strategy of partial volume irradiation might be avoided, even if it necessitates lowering the doses to treat large AVMs. Accuracy in the target determination is required, and complete stereoangiography is necessary.

Adult↗

PubMed1994

[Multiple cavernoma of delayed appearance].

The authors report on a right fronto-singular cavernous angioma which appeared, in a 46 year-old woman, four years after the excision of a right rolandic localization. Diagnosis suggested on radiological findings was confirmed by histological examination. After a review of the literature the authors discuss possible mechanisms of such delayed appearance of intra-cerebral cavernous angiomas. They suggest the possibility of infraradiologic stage corresponding to a micro-malformation characterized by abnormal capillaries, which has not been yet histologically modified by hemorrhages, thrombosis, fibrosis, gliosis and calcifications.

Brain Neoplasms↗

PubMed1992

[A rare case of intramedullary epidermoid cyst diagnosed by MRI].

Intramedullary epidermoid cysts are rare entities. A case recently seen on MRI led us to review the literature on the subject. A 9 year old boy developed in a four month-time a spastic paraparesis with a T7-T8 sensitive level. The MRI showed a widening of the spinal cord at the T6 level with an area of decreased signal on T1 weighted images, and a homogeneous round shaped area of increased signal on T2 weighted images. The authors discuss the contribution of MRI to the diagnosis of this lesion. The number of cases of intramedullar epidermoid cysts, like dermoid cysts, diagnosed with this neuroradiological method, is still very limited and the literature only mentions isolated cases.

Child↗

PubMed1991

[Terson's syndrome and intraocular complications in meningeal hemorrhages (26 cases)].

The Terson syndrome was described in the early 1900's as the association of an intra-vitreous humor bleeding and a subarachnoidal hemorrhage (SAH). The high jeopardy of blindness of such a syndrome emphasizes the importance of evaluating as soon as possible the presence of blood in the posterior chamber of patients presenting with a SAH. 250 patients admitted in the Neurosurgical Department of Ste Anne Hospital with a SAH were evaluated between January 1984 and February 1990. 26 had an intra-ocular hemorrhage (10.5%). In those cases the mortality rate was not increased (15.4%) but the morbidity rate was higher (42%). Concerning the intra-ocular bleeding, 4 patients underwent a vitrectomy (2 had a complementary photocoagulation). Only one patient had a visual sequela (partial decrease of visual acuity). These data emphasize the visual risk which has to be considered; a specific treatment (vitrectomy and/or photocoagulation) must be performed as quickly as possible so as to save the vision. In some particular instances, the ophthalmological treatment might even be necessary before the intracranial procedure itself.

Adolescent↗

PubMed1989

[Vertebral osteochondroma and trauma: a possible etiopathogenic correlation].

Three cases of vertebral osteochondroma are shown. The tumor was localized in the dorsal tract in two cases and in the lumbo-sacral junction in the other one. We found in all the cases, as a common anamnestic point, a clinical history of trauma. The etiopathological hypotheses are discussed and the hypothesis of a possible correlation between trauma and metaplastic osteochondromatosis is presented.

Adult↗

PubMedDate not supplied

For an elective surgical management in lumbar intervertebral disc herniation. Experience of 25 years of surgery.

On the base of a wide clinical experiences, the Authors report some consideration about relationship between clinical findings and neuroradiological pictures (plain film, myelography, CT and NMR) of the lumbar vertebral and disc diseases. It's pointed out the useful aspect of each imaging technique that contribute to obtain the more complete informations about anatomy of the lesion; such considerations allows the surgeon to plain the more adequate surgical technique. The Authors think myelography, still today, is the investigation of choice in this kind of pathology.

Adult↗