Mindful leadership for personal and organisational resilience.

Given that the volatility, uncertainty, complexity, and ambiguity (i.e., "VUCA" nature) of our world will likely continue to increase over time, it is clear that learning how to develop our inner capabilities of mindfulness and resiliency is of the utmost priority for us as individuals, organisations, communities, and nations. In today's world - and tomorrow's - such capacity development for ourselves, our leaders, and our organisations is vital to bringing a deeper wisdom and care to our lives and work, and to our human flourishing. In our increasingly VUCA world of ever-increasing complexity, old norms, skillsets, and "business and usual" norms are simply insufficient to assure sustainable success. The kind of high-performance protocols that were once reserved for world-class athletes, martial artists, elite military troops, and sports teams, or monastic adepts, have now become essential training for any leader, professional, or organisation intent on assuring high standards for safety, quality care, sustained success, well-being, and meaningful beneficial influence in their medical centres and communities. Could it be that the global surge of interest in mindfulness and resiliency reflects a wise and evolutionary impulse perfectly adapted and responsive to meeting the challenges and realising the opportunities of the VUCA world in which we live and serve as dedicated health caring providers and practitioners?

Psychological aspects of chronic tonic and clonic stuttering: suggested therapeutic approaches.

A comparison of the personality profiles and intellectual functioning of 12 tonic and 18 clonic stutterers indicated that the groups could be discriminated on measures of verbal IQ, object relations, social isolation, somatization, and cognitive processing. Findings are examined in terms of the impact of type of functioning on maintenance of stuttering, and implications for treatment are discussed.

The long internal loop of the alpha 3 subunit targets nAChRs to subdomains within individual synapses on neurons in vivo.

Different types of neurotransmitter receptors coexist within single neurons and must be targeted to discrete synaptic regions for proper function. In chick ciliary ganglion neurons, nicotinic acetylcholine receptors (nAChRs) containing alpha 3 and alpha 5 subunits are concentrated in the postsynaptic membrane, whereas alpha-bungarotoxin receptors composed of alpha 7 subunits are localized perisynaptically and excluded from the synapse. Using retroviral vector-mediated gene transfer in vivo, we show that the long cytoplasmic loop of alpha 3 targets chimeric alpha 7 subunits to the synapse and reduces endogenous nAChR surface levels, whereas the alpha 5 loop does neither. These results show that a particular domain of one subunit targets specific receptor subtypes to the interneuronal synapse in vivo. Moreover, our findings suggest a difference in the mechanisms that govern assembly of interneuronal synapses as compared to the neuromuscular junction in vertebrates.

Changes in the regulatory effects of cell-cell interactions on neuronal AChR subunit transcript levels after synapse formation.

Nicotinic acetylcholine receptors (AChRs) mediate excitatory synaptic transmission in the chick ciliary ganglion. AChR protein and mRNA levels are increased by both innervation and retrograde signals from target tissues during synapse formation. We now show that AChR alpha3, beta4, and alpha5 subunit transcript levels stop increasing after synaptogenesis. Moreover, maintenance of these mRNA levels requires the continued presence of regulatory signals from both pre- and postganglionic tissues. Unilateral preganglionic denervation or postganglionic axotomy causes declines in alpha3, beta4, and alpha5 transcript levels, ranging from twofold to 3. 5-fold, relative to contralateral control neuron values in newly hatched chicks. The reductions are not merely an injury response; cbeta4-tubulin mRNA levels are not affected by either axotomy or denervation. Further, similar decreases in AChR mRNA levels are observed after local application of colchicine to the postganglionic nerves, which blocks fast transport without disturbing axonal integrity. These results also demonstrate a developmental change in the regulatory effects of target tissues. Reductions in alpha5 mRNA levels caused by axotomy or colchicine treatment after peripheral synapse formation contrast with the lack of an effect on alpha5 when synapse formation with the target tissue is prevented. The ability of the target tissue to regulate alpha5 mRNA levels after synaptogenesis is interesting, because this subunit may be necessary for the formation of high-conductance AChRs. The specific regulatory effects of target tissues and inputs at different developmental stages demonstrate that neurons continually depend on signals from their pre- and postsynaptic tissues to accomplish mature levels of AChR subunit expression and optimal functioning of that neuronal circuit.

Innervation and target tissue interactions differentially regulate acetylcholine receptor subunit mRNA levels in developing neurons in situ.

Neurons engage in two distinct types of cell-cell interactions: they receive innervation and establish synapses on target tissues. Regulatory events that influence synapse formation and function on developing neurons are largely undefined. We show here that nicotinic acetylcholine receptor (AChR) subunit transcript levels are differentially regulated by innervation and target tissue interactions in developing chick ciliary ganglion neurons in situ. Using ganglia that have developed in the absence of pre- or postganglionic tissues and quantitative RT-PCR, we demonstrate that alpha 3 and beta 4 transcript levels are increased by innervation and target tissue interactions. In contrast, alpha 5 transcript levels are increased by innervation, but target tissues have little effect. Whole-cell ACh-induced currents, used to estimate the number of functional AChRs, change in correlation with alpha 3 and beta 4, but not alpha 5, transcript levels. A model is proposed in which the changes in AChR subunit expression regulate levels of synaptic activity, which is a critical determinant of synapse stabilization and elimination, and neuronal cell death.

Intracellular injection of vital dyes into single cells in the salamander olfactory epithelium.

Intracellular vital dye injection was used to examine the morphology of single sustentacular and receptor cells and the developmental fate of individual basal cells in the olfactory epithelium of the tiger salamander. In acute experiments, Lucifer yellow injections were used to identify single basal, receptor or sustentacular cells on the basis of their overall morphology. Dye-coupling between a number of the different epithelial cells was observed. Progeny of basal cells were examined by following labeled cells for up to 2 weeks using intracellular injection of rhodamine-labeled dextran. These experiments indicate that some olfactory epithelial cells are dye-coupled and that dye-filled basal cells can undergo division and migration.

Characterization of potential precursor populations in the mouse olfactory epithelium using immunocytochemistry and autoradiography.

There are at least two basal cell populations in the olfactory epithelium that could give rise to olfactory neurons during development, in the normal adult, and after experimentally induced receptor cell death. These populations have been subdivided as horizontal (HBC) and globose (GBC) basal cells on the basis of morphological criteria and by staining with antibodies against cytokeratin. HBCs are positive for cytokeratin while GBCs are negative. We have studied which cell type is induced to divide during receptor cell regeneration stimulated by olfactory bulbectomy using a combination of immunocytochemistry and autoradiography. By examining which population increases its labeling index with 3H-thymidine (3H-TdR) at various times after bulbectomy, it is shown that there is an increase in 3H-TdR uptake in the cytokeratin-negative GBCs with no change in the cytokeratin-positive HBCs. This suggests that the GBCs are specifically induced to divide in response to cues that accompany receptor cell death, and it is thus concluded that these cells are among the precursors of new olfactory receptor neurons.

Metastasizing chordoma in early childhood: report of a case at 1.5 T.

We present here the first report of an extraskeletal metastasizing presacral chordoma found in a child. MRI of this large lesion showed heterogeneous signal intensity on both the SE 550/30 and on SE 2440/100 images. MRI demonstrated this mass to be separate from the sacrum and provided nonionizing cross-sectional imaging prior to attempted surgical resection.

Differences in the frequency of ST segment depression during upright and supine exercise: assessment in normals and in patients with coronary artery disease.

Increased utilization of ambulatory ST segment monitoring mandates an appreciation of nonischemic variables that may influence the ST segment. While a greater frequency of ST segment depression has been reported with supine vs upright exercise, the relative false positive rate in both positions is not known. Thus, we compared the frequency of exercise ECG abnormalities during upright and supine bicycle exercise in two groups--17 normals and 46 patients with coronary artery disease. Exercise was performed in combination with radionuclide ventriculographic imaging. Peak exercise heart rate, peak systolic blood pressure, and exercise duration time were all slightly higher in the upright vs supine position (p less than 0.05). Nevertheless, the frequency of positive ST segment responses was more common in the supine position, both in the patients with coronary artery disease (54% vs 30%, p less than 0.05) and in the normal subjects (29% vs 6%, p = NS). The corresponding radionuclide ventriculographic responses, however, were normal during upright and supine exercise in 6 of the 11 CAD patients and in all five of the normal subjects with an abnormal ST segment response during supine exercise only. The frequency of exercise-induced chest pain was also similar in the two positions. Thus, we theorize that nonischemic factors may govern some positive ST segment responses in the supine position. This finding is of relevance for understanding the potential sources of physiologic false positive ST segment responses for ambulatory ST segment monitoring.

High-field MR surface-coil imaging of the hand and wrist. Part I. Normal anatomy.

High-resolution magnetic resonance (MR) images of the hands and wrists of six healthy volunteers were obtained at 1.5 T with a surface coil. Additionally, the hands and wrists of two fresh cadavers were imaged and were subsequently sectioned for anatomic correlation. High contrast when depicting soft-tissue, coupled with impressive spatial resolution and multiplanar capabilities, enabled delineation of fine structures including nerves, tendons, and blood vessels. Osseous and cartilaginous structures were also well depicted. MR imaging gives anatomic definition of the hand and wrist unmatched by other diagnostic imaging methods.

Extensive sarcoidosis involving the upper respiratory tract.

Sarcoidosis is a multisystem granulomatous disease without pathognomonic symptomatology or pathology. It may involve the upper respiratory tract, but this manifestation is rarely threatening. A case is reported here, in which extensive destruction of the larynx due to involvement by sarcoidosis necessitated tracheostomy. A review of the literature and a discussion of the therapeutic considerations are presented.

A civilian case of fatal meningococcemia due to Neisseria meningitidis, group Y.

The present report is that of a civilian episode of fatal, fulminant group Y meningococcemia in a previously healthy adolescent, who denied prior vaccination against group C meningococcus. The patient suffered abrupt onset of purpura, hypotension and cardiopulmonary arrest. A detailed clinical and pathologic report is included.

An unusual thyroid tumor in a child.

Malignant neoplasms of the thyroid gland are quite rare in children. Winship, in his classic article, could find only 562 cases in the literature. The histopathological patterns resemble those of the adult tumors. Despite early cervical metastasis, the prognosis in general is favorable, with many long-term survivals. Prior exposure to radiation of the head and neck is a definite pre-disposing factor. Teratomas of the neck are a medical curiosity--less than 100 cases are described in the literature. The vast majority of these are found during the neonatal period, and are benign histologically. These are usually large, cystic, bulky masses which produce mechanical obstruction of the upper airway and digestive tract. Only one of these tumors, described by Pupovac in 1896, has been considered malignant. A six-year-old child was examined with a right thyroid mass of three months' duration. The thyroid scan showed a "cold nodule." At surgery, a well-encapsulated mass was found. The pathology showed a predominance of malignant spindle cells, with areas of papillary carcinoma; however, there were well-defined mucous glands present in the tumor. Clinically the child has remained well and asymptomatic. The slides have been extensively reviewed. To my knowledge no such tumor has been previously described. The tumor is considered to be a malignant thyroid tumor growing out of teratomatous tissue.