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Biomedical subjects

O Hasson

Publications and source records attributed to O Hasson.

15 recordsLinked to original sources
PubMed2001

Autologous blood injection for treatment of recurrent temporomandibular joint dislocation.

OBJECTIVE: The purpose of this study was to reintroduce a rather simple, safe, minimally invasive, and rapid alternative procedure for the treatment of recurrent dislocation of the condyles. STUDY DESIGN: Subjects were 3 patients (5 joints) who suffered from recurrent condyle dislocation. The technique consisted of visually identifying a line from tragus to the eye angle. Then the articular fossa point was identified in this line, 10 mm anteriorly to tragus and 2 mm below the line. A 19-gauge needle was inserted at the articular fossa point. After injection of saline in the superior compartment, 5 cc of autologous blood drawn from the cubital fossa was injected (4 cc in the superior compartment and 1 cc in the pericapsular tissue). After this an elastic bandage was applied and left for the first 24 hours. Patients were advised to constrain their mandibular motion and to eat only soft foods for a week. They received cephalosporin antibiotics and nonsteroidal anti-inflammatory drugs for 7 days. A week after the procedure, supervised physiotherapy was started and the patients were encouraged to increase their mandibular opening to 40 mm. RESULTS: Postoperative recoveries were uneventful. Dislocation of condyles did not reoccur; however, patient no. 3 experienced an episode of unilateral subluxation. At follow-up all patients presented with normal mouth opening. CONCLUSION: Bleeding resulted from the introduction of a needle for injection in the pericapsular tissue. Blood coming from this wound, associated with autologous blood injected in the superior compartment, generates a bed for fibrous tissue formation in the region, creating a limitation of mandibular movement, thus ceasing dislocation of the condyles. Temporomandibular joint autologous blood injection is a simple procedure performed on an outpatient basis that we advise as an alternative treatment for patients with recurrent dislocation of the condyles.

Adult↗
PubMed2000

Body postures and patterns as amplifiers of physical condition.

The question of why receivers accept a selfish signaller's message as reliable or 'honest' has fuelled ample controversy in discussions of communication. The handicap mechanism is now widely accepted as a potent constraint on cheating. Handicap signals are deemed reliable by their costs: signallers must choose between investing in the signal or in other aspects of fitness. Accordingly, resources allocated to the signal come to reflect the signaller's fitness budget and, on average, cheating is uneconomic. However, that signals may also be deemed reliable by their design, regardless of costs, is not widely appreciated. Here we briefly describe indices and amplifiers, reliable signals that may be essentially cost free. Indices are reliable because they bear a direct association with the signalled quality rather than costs. Amplifiers do not directly provide information about signaller quality, but they facilitate assessment by increasing the apparency of pre-existing cues and signals that are associated with quality. We present results of experiments involving a jumping spider (Plexippus paykulli) to illustrate how amplifiers can facilitate assessment of cues associated with physical condition without invoking the costs required for handicap signalling.

Animals↗
PubMed2000

Pediatric sialolithiasis.

Pediatric sialolithiasis is a rare condition. This article characterizes 15 cases in children between 5 and 14 years of age. The diagnoses of this condition were made with routine radiograph and ultrasound, as well as with sialography whenever possible. Sialoendoscopy was performed as a diagnostic and treatment modality. Thirteen of the 15 affected children were boys, and 12 of 15 cases occurred in the submandibular gland. We were able to diagnose 67% by our imaging methods; the remainder were diagnosed by clinical examination.

Adolescent↗
PubMed1997

Towards a General Theory of Biological Signaling

Current models of biological communication point at evolutionary mechanisms of particular signal types. Those that present complete models look at the signals' equilibrium values and their evolutionary stability, and require two simultaneous equations: an equation that describes the signaler's fitness as a function of the signal and of the recipients' response, and a simultaneous equation that represents the fitness of recipients. This paper examines the effect of different signal types, such as handicaps, amplifiers, camouflage, mimicry etc, on the first equation. By considering parameters that affect the evolution of signals this paper first constructs a general model of biological signaling. Different signal types are then characterized by different sets of limiting assumptions. As a result, the fitness of a signaler of each signal type is represented by a unique equation that is a mathematical derivation of the general signaling model. This analysis enables a natural division of signals into groups and subgroups that share similar assumptions and properties. It shows the importance of signal design, and points at three methods by which signals may be reliable: by trade-offs between cost and benefits, by design and by convention. Copyright 1997 Academic Press Limited

Journal Article↗
PubMed1997

The predatory response of a stalking spider, Plexippus paykulli, to camouflage and prey type

When approaching prey, a stalking predator should consider trade-offs between the probabilities of early detection (by the prey, before the strike), spontaneous departure (of prey, before the strike), prey escape (following the strike) and interference (by rivals or predators). In this study we tested the response of a jumping spider, Plexippus paykullito a background with two different camouflaging properties, and two different prey types (maggots versus adult house flies). Spiders jumped towards adult house flies from greater distances on a non-camouflaging background, but background colour had no effect on jumping distance when the prey were maggots. Spiders stalking both prey types approached more slowly when camouflaged. Our experiments suggest that jumping spiders may be responding to changes in the trade-off relationships between the probabilities of early detection, spontaneous departure, escape and interference.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1989

Amplifiers and the handicap principle in sexual selection: a different emphasis.

Population genetic models have shown that female choice is a potential cause of the evolution of male display. In these models the display is assumed to be the immediate object of female choice. Here I present an explicit genetic model that shows that male display can evolve as a consequence of female choice even when the display is not the immediate object of choice. When females initially base their preferences on the existence of variance in a cue that is correlated with male viability, a rare display can evolve to fixation if it amplifies the previously recognized differences in males, (i.e. if it increases the resolution power of females with respect to the original cue). By definition, amplifying displays (or amplifiers) increase mating success of the more viable males and decrease mating success of the less viable males. Therefore, the higher the frequency of the preferred, more viable males, the more likely it is that amplifiers will evolve to fixation. The evolution of an amplifier is further facilitated by a genetic association that is built up between the amplifier allele and the more viable allele. If the expression of the amplifier is limited to the more viable males, the amplifier will evolve to fixation provided only that the change in total fitness to the more viable males (higher mating success, lower viability), is positive.

Alleles↗
PubMedDate not supplied

Acquired toxoplasmosis of a submandibular lymph node in a 13-year-old boy: case report.

Toxoplasmosis is a parasitic infection divided into congenital and acquired forms. In the latter form, malaise, fatigue, and lymphadenopathy are commonly found, and submandibular lymphadenopathy is sometimes a manifestation. In children, cervical lymph nodes usually are affected. This is a case of a 13-year-old boy suffering from acquired toxoplasmosis, in which submandibular lymphadenopathy was the only clinical sign of the disease. Meticulous history taking, clinical examination, and specific serological tests should be performed in these cases. Positive serological results will confirm toxoplasmosis infections. Conservative treatment must be attempted initially.

Adolescent↗
PubMedDate not supplied

Hemangiopericytoma of the tongue in an 11-year-old girl: case report and literature review.

Hemangiopericytoma is an uncommon vascular tumor of unknown etiology. The tongue is the most common site for this tumor in the oral cavity. Literature review disclosed 20 cases of hemangiopericytoma of the tongue, four of which were in the pediatric population. The treatment of choice is wide surgical excision. This tumor has a high rate of recurrence and often a malignant transformation. The literature is reviewed and an additional case is reported.

Child↗