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Biomedical subjects

A Apicella

Publications and source records attributed to A Apicella.

30 records · Page 2Linked to original sources
PubMed1989

Predominant left hemisphere metabolic dysfunction in dementia.

Thirty-one patients with probable Alzheimer's disease and 11 patients with memory disorders, attributable to multiple cerebral infarctions, were studied using 18-F-fluorodeoxyglucose-positron emission tomography scans. Asymmetry in cerebral glucose metabolism within these diagnostic groups was assessed by comparison with the metabolic rates obtained in age-equivalent healthy control subjects. A significantly greater number of individuals in both patient groups exhibited predominant left rather than right hemisphere hypometabolism. In addition, for patients with Alzheimer's disease, the degree of asymmetry was not related to either the severity or duration of dementia. These findings could be explained by greater susceptibility of the left hemisphere to degenerative or ischemic brain disease, by a specific sampling effect, or most likely, by greater metabolic deficits resulting from left rather than right hemisphere impairment.

Brain↗
PubMed1989

Two behavioral states studied in a single PET/FDG procedure: error analysis.

In a previous publication the theory, procedure, and results of a method were described for making two sequential measurements of cerebral metabolic rate for glucose (CMRglc), within a 2-hr period, using [18F]fluorodeoxyglucose. The error that is specific to this technique was estimated using computer simulations. CMRglc for the second state was sensitive to errors in (a) the values of the rate constants, (b) alignment of PET slices between the two scans, and (c) subtraction of one PET image from another. The root mean square of the average error from each error source was 6.4%, which gives the theoretical reliability of this method. The measured reproducibility, taken from our previous publication, was 4.2-6.2%, which is in good agreement with the present result. This method contributes a small additional error above that expected for two independent scans. However, independent scans done on different days are likely to be subject to larger physiological variations in CMRglc than would occur using this method.

Brain↗
PubMed1988

Sensitivity of cerebral glucose metabolism to age, gender, brain volume, brain atrophy, and cerebrovascular risk factors.

In 76 normal volunteers studied by positron emission tomography, with [18F]fluorodeoxyglucose, CMRglu was significantly lower in the elderly as compared with young subjects and significantly higher in females relative to males. However, in 58 of these subjects who also had magnetic resonance imaging scans, age and gender were found to be unrelated to CMRglu, when the effects of brain volume and brain atrophy on CMRglu were partialed out using covariate analyses. Individually, brain volume was found to have a significant effect on CMRglu, explaining approximately 17% of the variability in CMRglu measures and brain atrophy explaining approximately 8% of the variance in CMRglu. Together these two measures accounted for approximately 21% of the variance. Cerebrovascular risk factors in normal subjects were not found to affect mean CMRglu or the variability of CMRglu measures. In this study almost 80% of the variance in CMRglu could not be explained by any of the factors that had been considered. This implies a lack of sensitivity of absolute values of global CMRglu to the mild effects of brain dysfunction. Although some of the unexplained variance is probably methodological in origin, physiological factors that are difficult to quantify, such as the state of arousal, are likely to be contributory as well.

Adult↗
PubMed1988

Cerebral metabolic effects of a verbal fluency test: a PET scan study.

Sixteen normal volunteers were studied with [F-18] fluorodeoxyglucose and positron emission tomography scans during behavioral activation with a verbal fluency test, and 35 age-matched controls were studied with resting-state scans. There was an overall increase of the cerebral glucose metabolic rate of 23.3% during verbal fluency activation, compared to the resting state, with the greatest activation in bilateral temporal and frontal lobes. A negative correlation between test performance scores and indices of metabolism was found in frontal, temporal, and parietal regions. Damage to the left frontal lobe maximally affects scores on verbal fluency tests, but performing the test activates a network of regions, of which the left frontal lobe is only one. Proficient performance in verbal fluency seems to require less metabolic activation than poor performance, perhaps because of the efficiency of cognitive strategies employed.

Adult↗
PubMed1987

Behavioral activation and the variability of cerebral glucose metabolic measurements.

Variability in cerebral glucose metabolism was examined between and within subjects when paired studies were performed in the resting state or in a behaviorally activated state. Both normal and demented subjects were studied twice each, from 1 to 6 weeks apart, under near-identical conditions, using positron emission tomography (PET) and [18F]fluorodeoxyglucose. Resting state studies were repeated in nine normal and four demented subjects. A picture-viewing test, used for activation during PET, was used repeatedly in seven normal and five demented subjects. Within-subject variability, as assessed by the percent difference in metabolic rates in paired studies, was reduced by 60-70% for activation state compared to resting state studies in normals. It is concluded that PET studies of brain metabolism, which are designed to study the active brain, should indeed be performed in functionally activated states, as in addition to demonstrating metabolism during a defined functional state, activation studies show reduced variability of cerebral metabolic measures.

Aged↗
PubMed1987

Two behavioral states studied in a single PET/FDG procedure: theory, method, and preliminary results.

We have developed a method that allows two sets of regional cerebral metabolic rates of glucose (rCMRglc) to be obtained in a single extended procedure using positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG). This is an adaptation of the deoxyglucose method, with the addition of a second injection of FDG immediately after completion of the first scan, then followed 30 min later by a second scan. A model has been developed to allow for correction of measured tracer concentration in the second scan by subtracting the predicted remnant from the first scan. The possible applications of this method in studying behavior-metabolism relationships are demonstrated. The preliminary results show 6%-12% changes in rCMRglc values for appropriate brain regions when the behavioral state is altered, but show 0%-5% change in rCMRglc values when the behavioral state is unchanged. The method can contribute significantly to the understanding of behavior-metabolism relationships by allowing the noninvasive study of two behavioral states in a single PET procedure.

Brain↗
PubMedDate not supplied

Analysis of magnetization transfer effects on T1-weighted spin-echo scans using a simple tissue phantom simulating gadolinium-enhanced brain lesions.

The purpose of this study was to analyze the effect of several magnetization transfer (MT) pulse and T1-weighted spin-echo (SE) sequence parameters on lesion-to-background contrast, using a simple tissue phantom emulating the T1 relaxation and MT properties of gadolinium-enhanced brain lesions. Eggbeaters (Nabisco Inc., East Hanover, NJ) liquid egg product was doped with gadolinium in six concentrations from .0 to 1.0 mmol and cooked. The gadolinium-doped egg phantom and normal volunteer brains were studied using an SE sequence with TE = 20 msec and high power, pulsed, off-resonance MT saturation. The effects of MT pulse frequency offset (1,000-6,000 Hz), sequence repetition time (TR = 500-1,000 msec, with MT power held constant), and slice-select flip angle (60-120 degrees) on the magnetization transfer ratio (MTR) and the simulated lesion-to-background contrast were determined at the different "intralesion" gadolinium concentrations. The MTR and lesion-to-background contrast of all materials were greatest at narrow MT pulse frequency offsets. There was in inverse relationship between gadolinium concentration and MTR and a positive correlation between the gadolinium concentration and lesion-to-background (L/B) contrast, a weak negative correlation between slice-select flip angle and L/B, and a negative correlation between TR and L/B. The relaxation properties and MT behavior of the egg phantom are close to that expected for enhancing brain lesions, allowing a rigorous analysis of several variables affecting lesion-to-background contrast for high MT power, T1-weighted SE sequences.

Adult↗
PubMedDate not supplied

Prognostic significance of necrosis, elastosis, fibrosis and inflammatory cell reaction in operable breast cancer.

We analyzed retrospectively the relationships and the prognostic significance of four anatomopathological features (elastosis, fibrosis, necrosis, inflammatory cell reaction) of the primary tumor in a series of 1,457 cases of infiltrating ductal carcinoma observed at our institution from January 1978 to December 1991. Necrosis, elastosis, fibrosis and inflammatory cell reaction were strongly associated among themselves (all p < 0.0001), the only exception being necrosis and elastosis. Necrosis was significantly related to tumor size (odds ratio [OR] = 5.40, p < 0.0001) and tumor grade (OR = 2.22, p < 0.0001). Univariate analysis showed that the presence of necrosis and cell reaction were significantly related to worse survival (p < 0.0001 and p = 0.03, respectively). Multivariate analysis, including the four variables plus nodal status, tumor size, grading, adjuvant therapy, age and first order interactions, revealed that greater tumor size (p < 0.0001), positive nodal status (p < 0.0001), higher histologic grade (p < 0.0001) and presence of inflammatory cell reaction (p = 0.0007) independently worsened survival. On the other hand, adjuvant therapy had a significant independent role in preventing deaths (p = 0.03). The only first-order interaction retained in the model was that between grading and cell reaction (p = 0.002). Cell reaction had a different prognostic behaviour in the groups G1-G2 and G3: in the former group, survival was worse (p = 0.0001) when the inflammatory cell reaction was present. In conclusion, we demonstrate that cell reaction is an independent prognostic factor in the G1-G2 subgroup of patients, and propose a hypothesis as to the role of cell reaction in primary breast cancer.

Adolescent↗
PubMedDate not supplied

[Palatal angioleiomyoma. A clinical case].

A case of angioleiomyoma localized at the level of the soft palate is reported. The 31-year-old patient presented a non-pathognomonic clinical picture and the anamnestic finding of the relatively slow growth of the neoformation raised problems of differential diagnosis in relation to benign growth and lesion of a non-neoplastic nature. The differential diagnosis was only obtained with histological examination of biopsy material.

Adult↗
PubMedDate not supplied

Canalicular adenoma of the parotid gland: a case report.

Canalicular adenoma is an uncommon benign neoplasm that occurs almost exclusively in the upper lip and, very rarely, in other sites. We describe a case arising in the left parotid gland as a firm, painful mass, in order to underline morphological and immunohistochemical findings, particularly in relation to differential diagnosis with low-grade carcinomas of the salivary glands.

Adenoma↗