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Biomedical subjects

A Samuels

Publications and source records attributed to A Samuels.

At least 37 records · Page 2Linked to original sources
PubMed1998

Medicolegal aspects of managing deliberate self-harm in the emergency department.

Deliberate self-harm is a common reason for people to present to hospital. The management of this problem can cause ethical and legal difficulties to clinicians. This article describes a case of deliberate self-harm which we have used to illustrate answers to commonly asked questions about this difficult area. We make a case for such patients to be treated against their will under common law unless the use of the mental health act is clearly indicated. The Privacy Act appears to prohibit clinicians informing families about an episode of deliberate self-harm if the patient refuses consent. Clarification of "imminent threat to life or health" in the Privacy Act is needed.

Acetaminophen↗
PubMed1998

Topographic position of forelimb motoneuron pools is conserved in vertebrate evolution.

The neuromotor conservatism hypothesis predicts that neuromotor patterns in homologous tetrapod muscles are conserved evolutionarily despite the musculoskeletal modifications of vertebrate limbs. A complete description of the anatomical organization of the neurons innervating homologous limb muscles is a prerequisite to any test of the neuromotor conservatism hypothesis. This study uses the retrograde neuronal tracer WGA-HRP to selectively label the motor neuron pools of seven homologous forelimb muscles in mice (Mus musculus) and iguanas (Iguana iguana): Mm. pectoralis, spinodeltoideus, biceps brachii, lateral and long heads of triceps brachii, and the supraspinatus and infraspinatus (in mice) or their reptilian homolog, the supracoracoideus (in iguanas). In vertebrates, motoneurons are arranged in longitudinal columns of cells in the ventral horn of the spinal cord. Mouse motor pools average 1,952 microns in length, except the pectoralis pool which averaged 2,949 microns in length. Iguana pools average 3,196 microns in length. The number of neurons per pool ranged from 70-199 in mice and from 58-114 neurons in iguanas. In both iguanas and mice the motor pools for the spinodeltoids, biceps, and the supracoracoideus (or its mammalian homologs) lie anterior to the pectoralis and triceps motor pools. In the transverse plane, the pectoralis pool lies medial to those of the triceps. The pools of the biceps and spinodeltoids are located dorsal and lateral to those of the pectoralis and supracoracoideus (or its homologs in mammals). The resulting motor pool maps support the hypothesis that the anatomical organization of motoneurons in ancestral reptiles has been retained in these two tetrapod descendents.

Animals↗
PubMed1997

Influence of air inhomogeneities in radiosurgical beams.

The effect of air inhomogeneity on dose distribution in small diameter beams used in stereotactic radiosurgery (SRS) has been investigated. The measurements of the surface dose and central axis dose were made for a 6 MV photon beam with a diamond detector which has suitable radiologic properties for such measurements. Measurements made in a uniform density solid water phantom and in the presence of four air gaps indicate significant dose perturbation immediately beyond the air-solid water interface. The reduction in dose at the surface for a 12.5 mm diameter field is 11%, 17%, 23% and 33% for air gap thicknesses of 3, 4.6, 6 and 9.2 mm, respectively. The corresponding dose reduction for a 25 mm diameter field is 3%, 4%, 7% and 13%, respectively. The ratio of the dose with and without air inhomogeneity is highly dependent on field diameter and approaches 1.0 as the field diameter increases from 12.5 mm to 40 mm. The dose perturbation also increases with increase in air inhomogeneity thickness for all field diameters investigated. A dose buildup phenomenon is observed beyond the air gap with a shallow dmax of approximately 4-6 mm. Beyond the buildup region, a higher dose value compared to a homogeneous phantom is observed at all depths due to reduced photon attenuation in the air gap. The dose profiles beyond the air gap, measured with radiographic films, demonstrate no significant increase in the beam diameter but a pronounced broadening of the beam penumbra (80%-20% and 90%-10%) leading to enhanced dose outside the primary beam geometric edge and reduced dose inside the edge. The dose enhancement outside the beam edge increases with increase in air gap thickness.

Air↗
PubMed1997

Low dose amitriptyline in ankylosing spondylitis: a short term, double blind, placebo controlled study.

OBJECTIVE: To define the effect of low dose amitriptyline on fatigue, pain, and stiffness in patients with ankylosing spondylitis (AS). METHODS: One hundred consecutive patients with AS were randomized to receive low dose amitriptyline up to 30 mg nightly or placebo for 2 weeks. Patients were assessed by the Bath Ankylosing Spondylitis Disease Activity (BASDAI) and Functional (BASFI) Indices pre and post-treatment. RESULTS: Eighty-eight patients (44 amitriptyline, 44 placebo) completed the study. Eight (5 amitriptyline, 3 placebo) stopped treatment because of side effects (e.g., drowsiness, dryness of mouth) and 4 provided insufficient data. Compared to placebo, the patients taking amitriptyline showed significantly greater improvement in restful sleep (66 vs 20%; p < 0.001) and their disease activity scores [BASDAI amitriptyline 1.18 (23%) vs placebo 0.52 (10%); p = 0.024]. All other variables showed a trend to greater improvement by amitriptyline, although the differences were not statistically significant. CONCLUSION: (1) In a 2 week study, low dose amitriptyline significantly improved sleep in AS and was well tolerated; (2) as defined by BASDAI, there was a significant reduction in disease activity with amitriptyline; (3) compared to placebo, there was a nonsignificant trend toward improvement in function; and (4) in spite of improvement in pain, fatigue, and sleep with amitriptyline, stiffness was not increased.

Adult↗