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Biomedical subjects

T Rizzo

Publications and source records attributed to T Rizzo.

17 recordsLinked to original sources
PubMed2004

Spin-glass complexity.

We study the quenched complexity in spin-glass mean-field models satisfying the Becchi-Rouet-Stora-Tyutin supersymmetry. The outcome of such study, consistent with recent numerical results, allows, in principle, to conjecture the absence of any supersymmetric contribution to the complexity in the Sherrington-Kirkpatrick model. The same analysis can be applied to any model with a full replica symmetry breaking phase, e.g., the Ising p-spin model below the Gardner temperature. The existence of different solutions, breaking the supersymmetry, is also discussed.

Journal Article↗
PubMed2003

Chaos in temperature in the Sherrington-Kirkpatrick model.

We prove the existence of chaos in temperature in the Sherrington-Kirkpatrick model. The effect is exceedingly small, namely, of the ninth order in perturbation theory. The equations describing two systems at different temperatures constrained to have a fixed overlap are studied analytically and numerically, yielding information about the behavior of the overlap distribution function PT1(,T2)(q) in finite-size systems.

Journal Article↗
PubMed2002

Analysis of the infinity-replica symmetry breaking solution of the Sherrington-Kirkpatrick model.

In this work we analyze the Parisi infinity-replica symmetry breaking solution of the Sherrington-Kirkpatrick model without external field using high order perturbative expansions. The predictions are compared with those obtained from the numerical solution of the infinity-replica symmetry breaking equations, which are solved using a pseudospectral code that allows for very accurate results. With these methods we are able to get more insight into the analytical properties of the solutions. We are also able to determine numerically the end point x(max) of the plateau of q(x) and find that lim(T-->0)x(max)(T)>0.5.

Journal Article↗
PubMed1998

Attitudes of undergraduate physical education majors in Brazil toward teaching students with disabilities.

This study assessed the relationship of attitudes of physical education majors in Brazil to specific disabling conditions, i.e., Emotional and Behavioral Disorders, Specific Learning Disabilities, Moderate Mental Retardation, and Orthopedic Impairment. This study also identified which selected teachers' attributes, i.e., age, sex, years of teaching, course work in adapted physical education, course work in special education, years teaching students with disabilities, quality of teaching experience, and perceived competence were related to favorable attitudes. Analysis showed no significant differences toward teaching students with these disabilities. Simultaneous multiple regression procedure also showed perceived competence was the only statistically significant predictor of attitudes toward teaching such students.

Adult↗
PubMed1996

Advocate development in the field of developmental disabilities: a data-based conceptual model.

We proposed a taxonomy of advocate development in the field of developmental disabilities derived from the systematic evaluation of a Partners in Policymaking program. Three developmental stages evolved: beginner, involved, and activist. Self-reports of advocacy actions and outcomes were collected from 3 participants with disabilities and 21 parents before and during training. A follow-up, semi-structured telephone interview was conducted 5 months after training ended. Results indicate significant improvements in the number of actions and outcomes reported by all participants. The activist group had the largest gains in actions and outcomes; they reported twice as many outcomes as did the other participants. The implications of the proposed taxonomy for participants' recruitment in advocacy training programs were discussed.

Adolescent↗
PubMed1991

Correlations between antepartum maternal metabolism and intelligence of offspring.

BACKGROUND: It is not clear to what extent maternal metabolism during pregnancy affects the cognitive and behavioral function of the offspring by altering brain development in utero. To investigate this question, we correlated measures of metabolism in pregnant diabetic and nondiabetic women with the intellectual development of their offspring. METHODS: The study included 223 pregnant women and their singleton offspring: 89 women had diabetes before pregnancy (pregestational diabetes mellitus), 99 had the onset of diabetes during pregnancy (gestational diabetes mellitus), and 35 had normal carbohydrate metabolism during their pregnancy. We correlated measures of maternal glucose and lipid metabolism (fasting plasma glucose levels, hemoglobin A1c levels, episodes of hypoglycemia, episodes of acetonuria, and plasma beta-hydroxybutyrate and free fatty acid levels) with two measures of intellectual development in the offspring--the mental development index of the Bayley Scales of Infant Development, given at the age of two years, and the Stanford--Binet Intelligence Scale, given at the ages of three, four, and five years and expressed as an average of the three scores. RESULTS: After correction for socioeconomic status, race or ethnic origin, and patient group, the children's mental-development-index scores at the age of two years correlated inversely with the mothers' third-trimester plasma beta-hydroxybutyrate levels (r = -0.21, P less than 0.01); the average Stanford-Binet scores correlated inversely with third-trimester plasma beta-hydroxybutyrate (r = -0.20, P less than 0.02) and free fatty acid (r = -0.27, P less than 0.002) levels. No other correlations were significant. Including various perinatal events (e.g., prematurity and acidemia) in the analyses did not alter the results. CONCLUSIONS: Maternal diabetes during pregnancy may affect behavioral and intellectual development in the offspring. The associations between gestational ketonemia in the mother and a lower IQ in the child warrant continued efforts to avoid ketoacidosis and accelerated starvation in all pregnant women.

3-Hydroxybutyric Acid↗
PubMed1991

Long-term prospective evaluation of offspring of diabetic mothers.

We have suggested that altered maternal metabolism may affect the subsequent anthropometric and neuropsychological development of children who were in utero during disturbances in maternal fuel economy. This study reports the physical growth through 8 yr of age and the neuropsychological development through 4 yr of age in offspring of diabetic mothers (ODM). At birth, 50% of infants had weights greater than 90th percentile for gestational age. By 12 mo, length and weight were similar to the general population. Height remained normal until 7 yr of age, when it became slightly greater than average. After 5 yr of age, relative weight increased dramatically, and by 8 yr of age, half of the ODM had weights greater than 90th percentile. This childhood obesity in ODM is correlated with maternal prepregnant weight and independently with amniotic fluid insulin at 32-38 wk gestation. The Brazelton Neonatal Behavioral Assessment Scale (BNBAS) was administered to 185 newborn ODM. Significant correlations were found between poorer second- and third-trimester glycemic regulation and lower scores in three of four newborn BNBAS dimensions. The Stanford-Binet Intelligence Scale was measured in 102 ODM at 4 yr of age. We found an inverse correlation between childhood IQ and second- and third-trimester maternal lipid metabolism (serum free fatty acids and beta-hydroxybutyrate). This correlation is not explained by adverse perinatal events, socioeconomic status, maternal IQ, ethnicity, or diabetes type. These long-range associations between altered maternal metabolism and childhood growth and development continue to support Freinkel's hypothesis of fuel-mediated teratogenesis.

Aging↗
PubMed1991

Purification of lipid-associated basic protein from guinea pig spinal-cord myelin.

Myelin basic protein (MBP) was purified from guinea pig spinal-cord in a native-like form retaining the binding to all the myelin lipids. Since the guinea pig MBP was found to be much more labile than the corresponding MBP from bovine brain, the original procedure based on the use of hydroxyapatite and detergents was slightly modified as reported here. The product of this purification, lipid-bound MBP, may represent an alternative to lipid-free MBP for the induction, the study and the treatment of experimental allergic encephalomyelitis.

Animals↗
PubMed1991

Zinc as an inhibitor of myelin basic protein proteolytic breakdown in the central nervous system.

It is known that central nervous system myelin contains proteolytic enzymes which degrade the myelin basic protein (MBP). We have found that zinc acetate is able to inhibit MBP cleavage at concentrations of 1 mM or higher. Furthermore, the Zn-inhibitable MBP-degrading activity was found to be water-soluble and able to recognize MBP also if this protein was protected by its lipidic environment in the native-like, lipid-bound form. Data presented here suggest a Zn-dependent metallo-protease which recognize MBP as a substrate probably even in the myelin sheath, when the protein is not yet released from the membrane.

Animals↗
PubMed1990

Correlations between antepartum maternal metabolism and newborn behavior.

We suggested that antepartum maternal metabolism may affect later cognitive and behavioral function of progeny by impacting on developing brain cells in utero. This study reports on the observed relationships between serial characterizations of maternal fuels during pregnancy and Brazelton neonatal behavioral assessment scale ratings of offspring from 73 well-controlled pregestational diabetic patients, 112 gestational diabetic patients, and 24 nondiabetic patients. After controlling for the effects of premature birth on the Brazelton neonatal behavioral assessment scale, significant correlations were found between second- and third-trimester glycemic regulation (hemoglobin A1c and fasting plasma glucose levels) and three of four newborn behavioral dimensions of the Brazelton neonatal behavioral assessment scale. In each case, as maternal glucose increased, the newborns' Brazelton neonatal behavioral assessment scale responses were poor. Results were not substantially different when gestational and pregestational diabetic patients were analyzed separately, nor can they be attributed to various perinatal events (neonatal asphyxia, hypoglycemia) or differences in socioeconomic status or ethnicity. The presence of fuel-related neurobehavioral deficits in neonates of diabetic mothers suggests that such infants start their interactions with care givers from a modified base.

3-Hydroxybutyric Acid↗
PubMed1987

Usefulness of radionuclide ventriculography in assessment of coronary artery spasm.

Provocative tests that permit detection of coronary artery spasm are widely used in patients with ischemic syndromes. To assess the usefulness of radionuclide ventriculography combined with provocative tests for diagnosis of coronary spasm, the left ventricular (LV) response to exercise, hyperventilation and a cold pressor test was determined in 3 groups. Group I included 10 normal subjects; group II, 49 patients with typical effort angina and fixed obstructive coronary artery disease at catheterization; and group III, 19 patients suspected of having vasospastic angina based on clinical and electrocardiographic findings, each of whom had normal coronary angiographic findings. In group I, LV ejection fraction (EF) increased during hyperventilation and exercise testing in 9 of 10 subjects (90%) and failed to decrease 5% in 9 of 10 subjects (90%) during cold testing. In contrast, while 18 of 49 patients (37%) of group II showed LV dysfunction with cold testing and 8% with hyperventilation, all showed abnormal LV function during exercise. Finally, in group III, LVEF increased during exercise, mimicking the response in normal group, while dysfunction was present in 14 of 19 (74%) during hyperventilation and in 17 of 19 (89%) during cold testing. When results of hyperventilation and cold testing were combined, abnormal responses were present in all patients. Thus, radionuclide ventriculography, when performed in association with 3 forms of stress--exercise, hyperventilation and cold testing--allows accurate identification of patients likely to have coronary spasm.

Adult↗
PubMed1984

Stimulus selection in passive avoidance learning and retention: weanling, periadolescent, and young adult rats.

Periadolescent rats exhibit a number of behavioral differences in comparison with younger or older animals. For instance, periadolescents tend to show enhanced acquisition of simple active avoidance tasks, but impaired acquisition of more complex appetitive and aversive discriminations. In this experiment, rats were trained on a simple passive avoidance task at one of three ages, as weanlings (25 days), periadolescents (35 days), or young adults (45 days). Training occurred in the presence of both a redundant discriminative stimulus and a specified, redundant contextual stimulus. The periadolescents did not differ from either younger or older rats in rate of learning the passive avoidance task. The retention performance of these animals was then tested following a change in either, neither, or both of the redundant cues. When a measure of performance that controls for baseline activity was used, it was observed that periadolescents were not disrupted by a change in the redundant discriminative stimulus, a cue change that clearly disrupted performance in 25- and 45-day-old animals, and tended to be more disrupted by the contextual change than younger or older rats. It is hypothesized that the alterations in performance exhibited by periadolescents may be related to an ontogenetic alteration in stimulus selection modulated by the catecholaminergic systems.

Aging↗
PubMed1980

Analysis of staging and management of patients with sarcoma: a ten-year experience.

Over ten years, 70 patients with soft tissue sarcoma were treated for their primary tumors at the hospital of The Fox Chase Cancer Center. The clinical characteristics of these tumors are correlated with the outcome of various management efforts. The results of these evaluations identify three groups that can provide the basis for future treatment decisions and stratification for randomized studies of management options. The first group of patients, those with small well differentiated tumors, have no systemic spread regardless of the treatment modality used. The second group, those with large (greater than 5 cm) tumors that are moderately or poorly differentiated, do uniformly poorly despite the management techniques used. An intermediate group, those with high grade or large size but not both, have outcomes which may be correlated to treatment modalities.

Adolescent↗
PubMedDate not supplied

Comparison of the pick-and-smear and Saccomanno methods for sputum cytologic analysis.

The two methods of preparing sputum specimens for cytologic study, the (fresh) pick-and-smear technique and the (blended) Saccomanno technique, were compared using 249 consecutive specimens. Two slides were prepared for each specimen by each technique. Of the specimens, 103 showed squamous metaplasia, carcinoma in situ or carcinoma. A semiquantitative rating system (0 to 4+) was used to determine the number of diagnostic cells for each method for those 103 cases. More diagnostic cells were found on the Saccomanno preparations (217) than on the fresh preparations (154). There were 121 diagnostic cells in the Saccomanno preparations versus 95 diagnostic cells in the fresh preparations from 63 squamous metaplasias; 7 versus 3 for the preparations from 5 carcinomas in situ; 64 versus 42 from 28 squamous cell carcinomas; 3 versus 1 from 1 large cell undiffernomas; and 12 diagnostic cells in Saccomanno preparations versus 5 in fresh preparations from 3 small cell cancers. Twelve squamous metaplasias, two carcinomas in situ, four squamous carcinomas, one adenocarcinoma and one small cell cancer had no diagnostic cells on the fresh preparations; four squamous metaplasias and one squamous carcinoma had no diagnostic cells on the Saccomanno preparations. More diagnostic information and fewer false-negative results were achieved with the Saccomanno technique.

Adenocarcinoma↗