Matthew R. Kutcher

A structured communication adolescent guide (SCAG): assessment of reliability and validity

Purpose  To assess the reliability and validity of a Structured Communication Adolescent Guide (SCAG) in an undergraduate medical education setting using trained adolescent raters.

Hyperparathyroidism–jaw tumor syndrome

Hyperparathyroidism–jaw tumor (HPT‐JT) syndrome is a rare autosomal dominant multiple tumor syndrome characterized by hyperparathyroidism due to single or multiple‐gland parathyroid tumor(s). Since it was first described in 1990, the genetics underlying the syndrome have been elucidated and typical clinical presentations are becoming clarified as literature describing this rare entity amasses.

Recovery of neurofilament following early monocular deprivation

Postnatal development of the mammalian geniculostriate visual pathway is partly guided by visually driven activity. Disruption of normal visual input during certain critical periods can alter the structure of neurons, as well as their connections and functional properties. Within the layers of the dorsal lateral geniculate nucleus (dLGN), a brief early period of monocular deprivation can alter the structure and soma size of neurons within deprived-eye-receiving layers. This modification of structure is accompanied by a marked reduction in labeling for neurofilament protein, a principle component of the stable cytoskeleton. This study examined the extent of neurofilament recovery in monocularly deprived cats that either had their deprived eye opened (binocular recovery), or had the deprivation reversed to the fellow eye (reverse occlusion). The loss of neurofilament and the reduction of soma size caused by monocular deprivation were ameliorated equally and substantially in both recovery conditions after 8 days. The degree to which this recovery was dependent on visually driven activity was examined by placing monocularly deprived animals in complete darkness. Though monocularly deprived animals placed in darkness showed recovery of soma size in deprived layers, the manipulation catalyzed a loss of neurofilament labeling that extended to non-deprived layers as well. Overall, these results indicate that both recovery of soma size and neurofilament labeling is achieved by removal of the competitive disadvantage of the deprived eye. However, while the former occurred even in the absence of visually driven activity, recovery of neurofilament did not. The finding that a period of darkness produced an overall loss of neurofilament throughout the dLGN suggests that this experiential manipulation may cause the visual pathways to revert to an earlier more plastic developmental stage. It is possible that short periods of darkness could be incorporated as a component of therapeutic measures for treatment of deprivation-induced disorders such as amblyopia.

Eligibility for organ donation: a medico-legal perspective on defining and determining death

PurposeIn the context of post-mortem organ donation, there is an obvious need for certainty regarding the legal definition and determination of death, as individuals must be legally pronounced dead before organs may be procured for donation. Surprisingly then, the legal situation in Canada with regard to the definition and determination of death is uncertain. The purpose of this review is to provide anesthesiologists and critical care specialists with a medico-legal perspective regarding the definition and determination of death (particularly as it relates to non-heart-beating donor protocols) and to contribute to ongoing improvement in policies, protocols, and practices in this area.Principal findingsThe status quo with regard to the current legal definition of death is presented as well as the criteria for determining if and when death has occurred. A number of important problems with the status quo are described, followed by a series of recommendations to address these problems.ConclusionsThe legal deficiencies regarding the definition and determination of death in Canada may place health care providers at risk of civil or criminal liability, discourage potential organ donation, and frustrate the wishes of some individuals to donate their organs. The definition and criteria for the determination of death should be clearly set out in legislation. In addition, the current use of non-heart-beating donor protocols in Canada will remain inconsistent with Canadian law until more persuasive evidence on the potential return of cardiac function after cardiac arrest is gathered and made publicly available or until a concrete proposal to abandon the dead donor rule and amend Canadian law is adopted following a process of public debate and intense multidisciplinary review.RésuméObjectifDans le contexte d’un don d’organe post-mortem, il est évident qu’il est nécessaire de ne laisser la place à aucun doute quant à la définition et à la détermination du décès; en effet, un individu doit être déclaré légalement mort avant que ses organes ne puissent être utilisés pour un don. Dès lors, il est surprenant de noter que la situation légale au Canada concernant la définition et la détermination du décès est floue. L’objectif de ce compte-rendu est de proposer aux anesthésiologistes et intensivistes une perspective médico-légale quant à la définition et la détermination du décès (en particulier en ce qui touche aux protocoles de donneurs à cœur non-battant) et d’apporter notre contribution aux progrès continus en matière de politiques, de protocoles et de pratiques dans ce domaine.Constatations principalesNous présentons le statu quo concernant la définition légale actuelle du décès ainsi que les critères utilisés pour déterminer si et quand le décès est survenu. Plusieurs problèmes importants concernant le statu quo sont décrits; nous proposons ensuite une série de recommandations pour résoudre ces problèmes.ConclusionLes lacunes légales quant à la définition et la détermination du décès au Canada pourraient mettre les professionnels de la santé à risque de poursuites en responsabilité civile ou criminelle, décourager les dons d’organe potentiels, et frustrer le souhait de certaines personnes de faire don de leurs organes. La définition et les critères employés pour déterminer le décès devraient être clairement énoncés dans la loi. En outre, l’utilisation actuelle de protocoles de donneurs à cœur non-battant au Canada demeurera en contradiction avec la loi canadienne jusqu’à ce que davantage de données probantes convaincantes concernant le retour potentiel de la fonction cardiaque après un arrêt cardiaque soient récoltées ou rendues publiques, ou jusqu’à ce qu’une proposition concrète d’abandonner la règle du donneur décédé et d’amender la loi canadienne soit adoptée après un processus incluant un débat public et une révision pluridisciplinaire approfondie.

Cytoskeleton alteration correlates with gross structural plasticity in the cat lateral geniculate nucleus

Monocular deprivation during early development causes rearrangement of neural connections within the visual cortex that produces a shift in ocular dominance favoring the non-deprived eye. This alteration is manifested anatomically within deprived layers of the lateral geniculate nucleus (LGN) where neurons have smaller somata and reduced geniculocortical terminal fields compared to non-deprived counterparts. Experiments using monocular deprivation have demonstrated a spatial correlation between cytoskeleton alteration and morphological change within the cat LGN, raising the possibility that subcellular events mediating deprivation-related structural rearrangement include modification to the neuronal cytoskeleton. In the current study we compared the spatial and temporal relationships between cytoskeleton alteration and morphological change in the cat LGN. Cross-sectional soma area and neurofilament labeling were examined in the LGN of kittens monocularly deprived at the peak of the critical period for durations that ranged from 1 day to 7 months. After 4 days of deprivation, neuron somata within deprived layers of the LGN were significantly smaller than those within non-deprived layers. This structural change was accompanied by a spatially coincident reduction in neurofilament immunopositive neurons that was likewise significant after 4 days of deprivation. Both anatomical effects reached close to their maximum by 10 days of deprivation. Results from this study demonstrate that alteration to the neuronal cytoskeleton is both spatially and temporally linked to the gross structural changes induced by monocular deprivation.