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Biomedical subjects

Y Amit

Publications and source records attributed to Y Amit.

At least 19 recordsLinked to original sources
PubMed1999

A computational model for visual selection.

We propose a computational model for detecting and localizing instances from an object class in static gray-level images. We divide detection into visual selection and final classification, concentrating on the former: drastically reducing the number of candidate regions that require further, usually more intensive, processing, but with a minimum of computation and missed detections. Bottom-up processing is based on local groupings of edge fragments constrained by loose geometrical relationships. They have no a priori semantic or geometric interpretation. The role of training is to select special groupings that are moderately likely at certain places on the object but rate in the background. We show that the statistics in both populations are stable. The candidate regions are those that contain global arrangements of several local groupings. Whereas our model was not conceived to explain brain functions, it does cohere with evidence about the functions of neurons in V1 and V2, such as responses to coarse or incomplete patterns (e.g., illusory contours) and to scale and translation invariance in IT. Finally, the algorithm is applied to face and symbol detection.

Algorithms↗
PubMed1998

[Closed intramedullary nailing of forearm fractures in young patients].

Forearm bone fractures are commonly the result of falling on the outstretched hand or of direct injury. The preferred treatment is debated. The possible modalities are: application of a cast, often necessitating repeated manipulations; open reposition and fixation by plates and screws; or closed manipulation and closed intramedullary nailing. We present our favorable results in treating these fractures in young patients by closed intramedullary nailing, and compare them with the unfavorable results of this method in mature adults.

Adult↗
PubMed1997

Monteggia and equivalent lesions. A study of 41 cases.

Forty-one patients who suffered from a Monteggia fracture and were treated between 1984 and 1993 were reviewed retrospectively using a new motion score of the elbow joint. There were 14 children and 27 adults of whom 34 were available for review. The results in children were significantly better than those of the adults. Among the adults, the final results of the patients who had a Bado Type 1 equivalent injury were significantly worse than those of the other groups, especially when associated with a fracture of the radial head. The type of fracture, open or closed, the presence of a fracture of the olecranon, and the energy level of the trauma did not have any significant prognostic value. Good correlation was shown between the new motion score and the Figgie elbow score. The Bado Type 1 equivalent injuries should be considered as a special subgroup of the Monteggia lesion, necessitating extra attention in treatment and rehabilitation, and a close followup of the patient.

Adolescent↗
PubMed1997

Graphical shape templates for automatic anatomy detection with applications to MRI brain scans.

A new method of model registration is proposed using graphical templates. A decomposable graph of landmarks is chosen in the template image. All possible candidates for these landmarks are found in the data image using robust relational local operators. A dynamic programming algorithm on the template graph finds the optimal match to a subset of the candidate points in polynomial time. This combination--local operators to describe points of interest/landmarks and a graph to describe their geometric arrangement in the plane--yields fast and precise matches of the model to the data with no initialization required. In addition, it provides a generic tool box for modeling shape in a variety of applications. This methodology is applied in the context of T2-weighted magnetic resonance (MR) axial and sagittal images of the brain to identify specific anatomies.

Algorithms↗
PubMed1996

[3-Dimensional computerized imaging in complex pelvic fractures].

3-dimensional computerized imaging is a relatively new radiologic modality. The transformation of bi-plane CT images into 3-dimensions, enables the physician to rotate the desired region to any viewing angle. In complex anatomic regions such as the pelvis, it offers better visualization of lesions, avoids having to rotate the patient, and reduces the need for X-rays and exposure to radiation. Our preliminary results with this modality in 3 cases of complex fractures of the pelvis are presented.

Fractures, Bone↗
PubMed1995

Neonatal limb ischemia following maternal indomethacin treatment in twin pregnancies.

The prenatal administration of indomethacin in obstetric management has been implicated as a cause of neonatal cardio-pulmonary, gastrointestinal and renal complications. The present report describes two cases of twin pregnancy resulting in premature delivery at the 33rd and 30th week following prolonged maternal indomethacin treatment for 9 and 4 weeks respectively. Neonatal cardiovascular and renal complications were observed and an unusual severe ischemia of a lower limb occured in each of the first twins following insertion of an umbilical arterial line. It is suggested that prolonged antenatal exposure to the drug may increase the systemic arterial constrictive reactivity in some newborn infants and that special caution should be exercised during arterial catheterization of susceptible cases.

Cyclooxygenase Inhibitors↗
PubMed1994

[Coccidynia].

Explore the source record for details and available documents.

Coccyx↗
PubMed1993

Bilirubin inhibits protein kinase C activity and protein kinase C-mediated phosphorylation of endogenous substrates in human skin fibroblasts.

The primary target and molecular basis of bilirubin toxicity to cellular function are not known. We have studied the effect of bilirubin on protein kinase C activity in subcellular fractions of human skin fibroblasts and on protein kinase C-mediated phosphorylation of endogenous substrates. Bilirubin inhibited the kinase activity in a concentration-dependent manner: a 50% inhibition was achieved by 45 mumol/l in the homogenate and 75 mumol/l in both the cytosolic and membranous fractions. Inhibition of protein kinase C activity by bilirubin was reversed by increasing the concentrations of activating lipids in both the cytosolic and membranous fractions. Bilirubin-induced inhibition of phosphorylation of endogenous proteins, in both fractions, was noted in the presence of calcium and the activating lipids, but not in the absence of the activators. This inhibition may play a role in the pathogenesis of bilirubin toxicity.

Bilirubin↗
PubMed1993

Mathematical textbook of deformable neuroanatomies.

Mathematical techniques are presented for the transformation of digital anatomical textbooks from the ideal to the individual, allowing for the representation of the variabilities manifest in normal human anatomies. The ideal textbook is constructed on a fixed coordinate system to contain all of the information currently available about the physical properties of neuroanatomies. This information is obtained via sensor probes such as magnetic resonance, as well as computed axial and emission tomography, along with symbolic information such as white- and gray-matter tracts, nuclei, etc. Human variability associated with individuals is accommodated by defining probabilistic transformations on the textbook coordinate system, the transformations forming mathematical translation groups of high dimension. The ideal is applied to the individual patient by finding the transformation which is consistent with physical properties of deformable elastic solids and which brings the coordinate system of the textbook to that of the patient. Registration, segmentation, and fusion all result automatically because the textbook carries symbolic values as well as multisensor features.

Algorithms↗
PubMed1993

Age-dependent sensitivity of cultured rat glial cells to bilirubin toxicity.

The results of studies conducted in neural tissues and neuronal cell lines suggest that bilirubin is toxic to various cellular functions. Using stable bilirubin solutions and primary cultures of fetal rat glial cells we report on the toxic effects of bilirubin on cell morphology, cell viability, and mitochondrial function. Glial cells in culture exhibit age-in-culture-dependent sensitivity to bilirubin toxic effects. Between the ages of 2 and 12 days in vitro, a gradual tolerance to bilirubin developed. Bilirubin exposure resulted in 55, 22, and 5% decreases in mitochondrial function in 4-, 8-, and 12-day-old cells in culture, respectively. In addition, bilirubin toxicity was dependent on bilirubin-albumin molar ratio and bilirubin concentration and only partially dependent on length of exposure. The age-dependent phenomenon raises concern regarding the potential toxicity associated with exposure of premature neural cells to bilirubin.

Animals↗
PubMed1993

Effect of skinfold thickness on transcutaneous bilirubin measurements.

We studied the effect of skinfold thickness on the correlation between serum total bilirubin level and transcutaneous bilirubin (TcB) readings. Skinfold thickness measurements were taken at 1-4 h of age. Serum total bilirubin levels and TcB readings were obtained at 1-4 (first) and 44-56 h of age (discharge). No correlation was found between first reading and skinfold thickness (rho = -0.196), whereas correlations with first serum bilirubin level and blood hematocrit were 0.397 and -0.373, respectively. The correlation between discharge serum total bilirubin level and TcB reading was affected by skinfold thickness, and not improved with the use of first reading as a reference for discharge reading.

Bilirubin↗
PubMed1993

Standards of skinfold thickness and anthropometric indices in term Israeli newborn infants.

Anthropometric measurements including weight, length, head and mid-arm circumferences, skinfold thickness (biceps, triceps, subscapular, abdominal, suprailiac and quadriceps) were obtained from 250 singleton, full-term infants within 4 h of birth. Anthropometric indices for total body fat stores such as arm fat and nonfat areas, adiposity and ponderal indices, and weight/length ratio were calculated. These data may be helpful in determining nutritional status at birth and assessing postnatal growth of Israeli infants.

Anthropometry↗
PubMed1992

Neonatal jaundice and bilirubin encephalopathy: a clinical and experimental reappraisal.

Hyperbilirubinemia and bilirubin encephalopathy are well-known occurrences in the neonatal period. The fact that bilirubin might be toxic to neural cells stems from the neurological picture that has emerged and the associated hyperbilirubinemia. Studies of the relationship between hyperbilirubinemia in healthy full-term infants and the long-term consequences showed little or no effect of bilirubin. Nevertheless, bilirubin is still considered toxic to premature infants and infants with hemolysis. In addition, in spite of a fairly detailed understanding of the chemistry of bilirubin and the biochemistry of bilirubin metabolism, the primary target of its toxic effect is still not known. The difficulties in analyzing the results are due to the variation in experimental designs, the use of different animal models and cell systems and the use of unstable bilirubin solutions. We review some of the problems related to clinical and experimental studies of bilirubin toxicity.

Animals↗
PubMed1991

Intravenous immunoglobulin for Flavobacterium-induced thrombocytopenia in a premature infant.

Gram-negative septicemia at times causes morbidity and mortality in newborn nurseries. Prophylactic intravenous immunoglobulin results in a significant decrease in incidence and severity of septicemia resulting from infection in infants. The present case report describes the successful use of high-dose intravenous immunoglobulin in a Flavobacterium-induced thrombocytopenia in a premature infant.

Bacterial Infections↗