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Biomedical subjects

Y Amit

Publications and source records attributed to Y Amit.

At least 19 recordsLinked to original sources
PubMed2001

Synoviorthesis with radioactive Yttrium in haemophilia: Israel experience.

Radioactive Yttrium-90 (90Y) was injected into 163 joints. Of these patients 115 were persons with haemophilia and they suffered from recurrent haemarthroses. The median age at the time of the initial exposure to 90Y was between 11 and 15 years and the median follow-up period 11 years. Over 80% of the patients with haemophilia reported a decrease in the number of haemarthroses and 15% stopped bleeding altogether in the treated articulation. The safety of this modality of management has been reported and hence the patients age should not be regarded as a criteria.

Adolescent↗
PubMed2001

Attractor networks for shape recognition.

We describe a system of thousands of binary perceptrons with coarse-oriented edges as input that is able to recognize shapes, even in a context with hundreds of classes. The perceptrons have randomized feedforward connections from the input layer and form a recurrent network among themselves. Each class is represented by a prelearned attractor (serving as an associative hook) in the recurrent net corresponding to a randomly selected subpopulation of the perceptrons. In training, first the attractor of the correct class is activated among the perceptrons; then the visual stimulus is presented at the input layer. The feedforward connections are modified using field-dependent Hebbian learning with positive synapses, which we show to be stable with respect to large variations in feature statistics and coding levels and allows the use of the same threshold on all perceptrons. Recognition is based on only the visual stimuli. These activate the recurrent network, which is then driven by the dynamics to a sustained attractor state, concentrated in the correct class subset and providing a form of working memory. We believe this architecture is more transparent than standard feedforward two-layer networks and has stronger biological analogies.

Animals↗
PubMed2001

Narrative group therapy with aging child survivors of the Holocaust.

Child survivors of the Holocaust, aged 1-16 years at liberation in 1945, now well beyond mid-life, are approaching the gerontic stage of their psychosocial development. They find themselves confronted with the demands of aging, as well as unmet needs related to their damaged early development. AMCHA, the National Israeli Center for Psychosocial Support of Holocaust Survivors and the Second Generation, attempted to create a framework for exploring and meeting these needs. An account is given of a narrative group consisting of aging, non-clinical child survivors who met once monthly over a period of more than five years. The individual narratives spun out within the group meetings weave a common texture which served as a context for mutual recognition, dialogue and restoration of meaning to fragmented childhood memories. Retrieval of the lost life stories served as a bridge for the belated "homecoming" of the "lost children." One of the problems is how to resolve the group with the right amount of tears because, regardless of the achievements, mourning is not completed.

Adolescent↗
PubMed2000

The epidemic of ankle fractures in the elderly--is surgical treatment warranted?

Ankle fractures in the elderly are extremely common (up to 184 fractures per 100,000 persons per year, and of these approximately 20%-30% occur in the elderly). The medical literature contains no research that has investigated ankle fractures in the elderly. A prospective, randomised study was conducted of 84 patients with displaced ankle fractures, who were over the age of 65 years and were assigned to operative or conservative treatment after closed reduction. The results of treatment assessed according to the American Orthopedic Foot and Ankle Society (AOFAS) Score showed a mean of 91.37 +/- 8.96 in the non-operated group compared with 75.2 +/- 14.38 (P = 0.001) in the operated group. The costs of treatment were accordingly higher. These results call for consideration of a non-operative approach to the treatment of well-reduced ankle fractures in the elderly. Increased efforts should be invested in the prevention of these common fractures.

Age Factors↗
PubMed2000

Total hip arthroplasty in patients with below-knee amputations.

We present a unique small group of 5 patients with below-knee amputation who underwent total hip arthroplasty after a displaced subcapital fracture of the femur. Three patients were operated on after failed fixation of the fracture, and 2 were operated on as a primary procedure. All 5 patients resumed their prefracture level of activity and mobilization with no deterioration during follow-up (average, 69 months [range, 22-98]). These encouraging results call for use of total hip arthroplasty or hemiarthroplasty as the primary treatment modalities of patients with displaced subcapital femoral head fracture in an extremity with below-knee amputation.

Aged↗
PubMed2000

A neural network architecture for visual selection.

This article describes a parallel neural net architecture for efficient and robust visual selection in generic gray-level images. Objects are represented through flexible star-type planar arrangements of binary local features which are in turn star-type planar arrangements of oriented edges. Candidate locations are detected over a range of scales and other deformations, using a generalized Hough transform. The flexibility of the arrangements provides the required invariance. Training involves selecting a small number of stable local features from a predefined pool, which are well localized on registered examples of the object. Training therefore requires only small data sets. The parallel architecture is constructed so that the Hough transform associated with any object can be implemented without creating or modifying any connections. The different object representations are learned and stored in a central module. When one of these representations is evoked, it "primes" the appropriate layers in the network so that the corresponding Hough transform is computed. Analogies between the different layers in the network and those in the visual system are discussed. Furthermore, the model can be used to explain certain experiments on visual selection reported in the literature.

Algorithms↗
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↗
PubMed1999

Primary reconstruction of traumatic bony defects using allografts.

We retrospectively reviewed 207 patients suffering from traumatic bone defect who had been treated at our institution between 1973 and 1993. Three types of traumatic bone defects were identified: I, minor; II, major cortical; III, major articular. Each type was further subdivided into: A, open injury; B, closed injury. The proposed treatment modality of each type was included within each classification. Types II and III posed the greatest difficulties in management. However, massive bone allografts can be successfully used in these situations, even in the early phases of treatment, but only given specific prerequisites.

Accidental Falls↗
PubMed1999

Twenty-five years of clinical experience with bone banking in Israel.

BACKGROUND: Bone banking and the clinical use of banked tissue are the most common forms of allopreservation and transplantation in modern medicine. OBJECTIVES: This article reviews 25 years (1973-98) of experience in bone banking in Israel. METHODS: A nationwide survey on the clinical application of the banked musculoskeletal tissues during 1996 was conducted by means of a written questionnaire sent to all orthopedic departments in Israel. RESULTS: The response rate to the questionnaire was 84%. A total of 257 cases were allocated bone allografts: the majority comprised 225 spongy bones, 26 were massive bone allografts and 6 were soft tissue allografts. CONCLUSION: Improvement of quality control and quality assurance of the banked tissues, together with development of skills in the use of osteoinductive and osteoconductive materials, cast the future of musculoskeletal tissue banking.

Bone Banks↗
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].

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Coccyx↗