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Biomedical subjects

Frank Accurso

Publications and source records attributed to Frank Accurso.

8 recordsLinked to original sources
PubMed2006

A new synaptic plasticity rule for networks of spiking neurons.

In this paper, we describe a new Synaptic Plasticity Activity Rule (SAPR) developed for use in networks of spiking neurons. Such networks can be used for simulations of physiological experiments as well as for other computations like image analysis. Most synaptic plasticity rules use artificially defined functions to modify synaptic connection strengths. In contrast, our rule makes use of the existing postsynaptic potential values to compute the value of adjustment. The network of spiking neurons we consider consists of excitatory and inhibitory neurons. Each neuron is implemented as an integrate-and-fire model that accurately mimics the behavior of biological neurons. To test performance of our new plasticity rule we designed a model of a biologically-inspired signal processing system, and used it for object detection in eye images of diabetic retinopathy patients, and lung images of cystic fibrosis patients. The results show that the network detects the edges of objects within an image, essentially segmenting it. Our ultimate goal, however, is not the development of an image segmentation tool that would be more efficient than nonbiological algorithms, but developing a physiologically correct neural network model that could be applied to a wide range of neurological experiments. We decided to validate the SAPR by using it in a network of spiking neurons for image segmentation because it is easy to visually assess the results. An important thing is that image segmentation is done in an entirely unsupervised way.

Algorithms↗
PubMed2006

Introduction to the newborn screening fact sheets.

Newborn screening fact sheets were last revised in 1996 by the Committee on Genetics of the American Academy of Pediatrics. These fact sheets have been revised again because of advances in the field, including technologic innovations such as tandem mass spectrometry, as well as greater appreciation of ethical issues such as informed consent. The fact sheets provide information to assist pediatricians and other professionals who care for children in performing their essential role within the newborn screening public health system. The newborn screening system consists of 5 parts: (1) newborn testing; (2) follow-up of abnormal screening results to facilitate timely diagnostic testing and management; (3) diagnostic testing; (4) disease management, which requires coordination with the medical home and genetic counseling; and (5) continuous evaluation and improvement of the newborn screening system. The following disorders are reviewed in the newborn screening fact sheets (which are available at www.pediatrics.org/cgi/content/full/118/3/e934): biotinidase deficiency, congenital adrenal hyperplasia, congenital hearing loss, congenital hypothyroidism, cystic fibrosis, galactosemia,homocystinuria, maple syrup urine disease, medium-chain acyl-coenzyme A dehydrogenase deficiency, phenylketonuria, sickle cell disease and other hemoglobinopathies,and tyrosinemia.

DNA↗
PubMed2006

Newborn screening fact sheets.

Newborn screening fact sheets were last revised in 1996 by the American Academy of Pediatrics Committee on Genetics. This revision was prompted by advances in the field since 1996, including technologic innovations, as well as greater appreciation of ethical issues such as those surrounding informed consent. The following disorders are discussed in this revision of the newborn screening fact sheets: biotinidase deficiency, congenital adrenal hyperplasia, congenital hearing loss, congenital hypothyroidism, cystic fibrosis, galactosemia, homocystinuria, maple syrup urine disease, medium-chain acyl-coenzyme A dehydrogenase deficiency, phenylketonuria, sickle cell disease and other hemoglobinopathies, and tyrosinemia. A series of topics related to newborn screening is discussed in a companion publication to this electronic publication of the fact sheets (available at: www.pediatrics.org/cgi/content/full/118/3/1304). These topics are newborn screening as a public health system; factors contributing to the need for review of the newborn screening system; informed consent; tandem mass spectrometry; DNA analysis in newborn screening; status of newborn screening in the United States; and the effect of sample timing, preterm birth, diet, transfusion, and total parenteral nutrition on newborn screening results.

Blood Transfusion↗
PubMed2005

Frequency of ASCA seropositivity in children with cystic fibrosis.

OBJECTIVE: To determine the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) seropositivity in pediatric patients with cystic fibrosis (CF) and correlate ASCA with clinical features. METHODS: Prospective study of children with CF aged 2 to 21 years enrolled from The Children's Hospital Cystic Fibrosis Center. Exclusion criteria included Crohn disease, immunodeficiency or immunoglobulin A deficiency. The frequency of ASCA (ASCA immunoglobulin A and immunoglobulin G) was measured by an enzyme-linked immunosorbent assay kit provided by Inova, Inc. (San Diego, CA). The CF Foundation database was queried for clinical data on ASCA seropositive patients. RESULTS: Seventeen (20.7%) of 82 patients were seropositive for ASCA. Of these, eight had immunoglobulin A antibodies, six had immunoglobulin G antibodies and three had both. ASCA seropositivity in CF patients was significantly greater than the general population (20.7% versus 4%, P < 0.0001), using an exact binomial test on a single proportion. The 95% confidence limits around our observed proportion were 12.6% to 31.1%. Of 17 ASCA positive patients, 1 (5.8%) had a history of meconium ileus, 14 (82.4%) had DeltaF508 gene mutation, 9 (52.9%) had positive sputum cultures for fungal organisms, and 17 (100%) had an ideal body weight % >or=85%. CONCLUSION: Patients with CF have a higher frequency of ASCA seropositivity than the general population. When evaluating CF patients for Crohn disease, ASCA should be used with caution. The reasons for higher ASCA seropositivity in CF patients are unknown, but may include exposure to fungal organisms via intestinal or pulmonary sources.

Adolescent↗
PubMed2002

Significant microbiological effect of inhaled tobramycin in young children with cystic fibrosis.

We conducted a double-blind, placebo-controlled, multicenter, randomized trial to test the hypothesis that 300 mg of tobramycin solution for inhalation administered twice daily for 28 days would be safe and result in a profound decrease in Pseudomonas aeruginosa (Pa) density from the lower airway of young children with cystic fibrosis. Ninety-eight subjects were to be randomized; however, the trial was stopped early because of evidence of a significant microbiological treatment effect. Twenty-one children under age 6 years were randomized (8 active; 13 placebo) and underwent bronchoalveolar lavage at baseline and on Day 28. There was a significant difference between treatment groups in the reduction in Pa density; no Pa was detected on Day 28 in 8 of 8 active group patients compared with 1 of 13 placebo group patients. We observed no differences between treatment groups for clinical indices, markers of inflammation, or incidence of adverse events. No abnormalities in serum creatinine or audiometry and no episodes of significant bronchospasm were observed in association with active treatment. We conclude that 28 days of tobramycin solution for inhalation of 300 mg twice daily is safe and effective for significant reduction of lower airway Pa density in young children with cystic fibrosis.

Administration, Inhalation↗
PubMed2002

Inefficient transduction of sheep in utero after intra-amniotic injection of retroviral producer cells.

OBJECTIVE: Our purpose was to test the hypothesis that the intra-amniotic injection of a retroviral vector producer cell line into pregnant sheep will result in retrovirus-mediated transduction and stable gene transfer to the ovine fetus. STUDY DESIGN: Thirteen pregnant ewes at various gestational ages underwent amniocentesis and injection of cells producing the retrovirus vector LIRESgeo, which is derived from Maloney murine leukemia virus and encodes Escherichia coli LacZ (beta-galactosidase) as a marker gene. Pregnant ewes and fetuses were killed, and amniotic fluid, placenta, and fetal tissues were collected and assayed for transgene expression 7 to 77 days after intraamniotic injection. In addition, serum was collected and analyzed for evidence of specific immune responses against the producer cells, and amniotic fluid was collected and analyzed for deleterious effects on producer cell viability, vector production, and vector transduction. RESULTS: Only 1 of 10 fetuses exposed to the retroviral producer cells demonstrated beta-galactosidase activity that correlated with positive immunohistochemistry for LacZ in lung, trachea, pancreas, and small intestine. However, the presence of the LacZ gene could not be confirmed by polymerase chain reaction. Thus, we could not confirm transduction after any of the injections. The retroviral producer cells survived well in amniotic fluid and continued to produce high levels of retroviral vector after intra-amniotic injection, although amniotic fluid inhibited the transducing activity of the vector in a manner dependent on gestational age. CONCLUSIONS: Intra-amniotic retroviral gene transfer with the use of these amphotropic producer cells does not result in reproducible gene transfer in the ovine fetus although amniotic fluid sustains producer cell viability and vector production. Possible reasons for the inefficient transduction are discussed.

Amniocentesis↗