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Biomedical subjects

M J Davis

Publications and source records attributed to M J Davis.

193 records · Page 11Linked to original sources
PubMedDate not supplied

Calcium-release-activated calcium influx in endothelium.

Signaling pathways activated by the tachykinin substance P (SP) were investigated in pig coronary artery endothelial cells (PCAECs). Single cells were obtained after enzymatic digestion of coronary arteries. Intracellular Ca2+ ([Ca2+]i) was measured from fura-2 fluorescence while membrane potential or ionic current was measured using patch-clamp techniques. In physiological saline solution, SP induced hyperpolarizations or outward currents which coincided with biphasic [Ca2+]i increases representing store release of Ca2+ and Ca2+ influx. Single channel recording protocols showed that both sources of Ca2+ activated a small conductance K+ channel, resulting in cell hyperpolarization. When outward currents were blocked by d-tubocurare, Cs+, or BAPTA, an inward current was unmasked. Ion substitution protocols showed that the SP-induced inward current was (1) carried by a mixture of Ca2+ and Na+, (2) blocked by La3+, and (3) inactivated by high extracellular [Ca2+]. Tyrosine kinase inhibitors also blocked the inward current. The same current was activated by bath application of BHQ, an inhibitor of the endoplasmic reticulum Ca2+ ATPase, or by cell dialysis with IP3. These results suggest that the plateau phase of the agonist-activated [Ca2+]i increase in PCAECs reflects Ca2+ entry through a depletion-activated Ca2+ channel. The characteristics of this channel are compared to those of Ca2+ channels found in other nonexcitable cells.

Animals↗
PubMedDate not supplied

Contrast radiographic findings in canine bacterial discospondylitis: a multicenter, retrospective study of 27 cases.

A multicenter, retrospective study was undertaken to evaluate contrast radiographic findings in canine bacterial discospondylitis. Records and myelograms or epidurograms of 27 patients were obtained from five colleges of veterinary medicine. Fifteen cases (56%) were evaluated as having some degree of spinal cord compression. The majority (73.3%) of the cases had only soft tissue as the compressive mass. The median compression for all cases was 5% of the vertebral canal. No difference was noted for compression based on anatomical site (i.e., cervical versus thoracolumbar versus lumbosacral). No significant correlation between degree of lesion compression and clinical outcome was noted, but there was a trend toward increased mortality with greater compression. There was no correlation between the ambulatory status and the ultimate outcome. Three of the 15 (20%) cases showed vertebral subluxation. Results of this study indicate that static spinal cord compression is not a significant component of the neurological dysfunction associated with bacterial discospondylitis. Identification of vertebral subluxation in some patients may indicate a dynamic lesion that should be evaluated with stress radiography.

Animals↗
PubMedDate not supplied

Pediatric dentistry workforce issues: a task force white paper. American Academy of Pediatric Dentistry Task Force on Work Force Issues.

The number of current practitioners, academicians, and researchers in Pediatric Dentistry is clearly not adequate to meet the need and demand. The shortage in academia is dire. Simply put, not enough pediatric dentists are being trained. The rate limiting factor is the number of training positions. The American Academy of Pediatric Dentistry established a "Task Force on Work Force Issues" approximately 18 months ago and charged that group to seek methods for creating more training positions. This paper reflects the Task Force deliberations, documents the shortage of pediatric dental specialists, and recommends tactics for amelioration.

Child↗
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Restoring the oral health of the child.

We practice in a country in which 80 percent of oral disease is localized in 20 percent of the children. Restorative care is not about to vanish from the face of the earth, however. Present practice and treatment protocols, and those of the future, are necessarily based on an evolutionary development of restorative dentistry over a period of the last twenty years. The explosion in the use of adhesive technologies and the attention to acceptable esthetics come to the forefront of important developments, as will be the identifying and employing of truly biologically compatible materials. What are also needed are continuing efforts to develop new modalities of restorative care, pulp therapy, and trauma care. Advances in these areas are reviewed; they first appeared in the Journal under editor George Teuscher's selecting and publishing for the profession significant articles that advanced dentistry for the child and the adolescent.

Adolescent↗
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Glutaraldehyde: an alternative to formocresol for vital pulp therapy.

Based on the limited results of this eight-week comparison of formocresol and glutaraldehyde, it would appear that glutaraldehyde may offer distinct advantages over formocresol, in the treatment of cariously exposed primary and young permanent teeth. In particular, due to its chemical structure, it is more active in fixing the surface tissues and is more rapidly limited in its depth of penetration through these tissues. Glutaraldehyde does not exhibit as significant an ability to induce the total loss of vitality, in the radicular pulp tissues. The progression of formocresol treated pulps to apparent fibrotic replacement via granulation-tissue ingrowth, through the apex, does not occur with the glutaraldehyde-treated pulp tissues. There may, however, be a slow progression of fibrotic replacement of the glutaraldehyde fixed tissue, in the coronal portion of the radicular pulp. Perhaps most importantly it would seem that since the glutaraldehyde does not perfuse the tissues to the apex, it will not demonstrate systemic distribution and other extradental phenomena, as have been identified with the use of formocresol

Aldehydes↗
PubMedDate not supplied

Orofacial trauma management. Patient assessment and documentation.

New technologies and treatments for managing children with orofacial trauma are constantly updated and available to the practitioner through current literature. What often fails to be appreciated, however, is that orofacial injury is a subset of head trauma and may have systemic emergent considerations that supersede the oral conditions being addressed. The complexity of a thorough assessment of the child from both medical and dental standpoints requires a systematic approach, which in turn can be guided by an appropriate document for inclusion in the chart. Further, such a document will serve as an important record should future civil litigation ensure from the traumatic incident.

Child↗
PubMedDate not supplied

Neurological assessment of the child with head trauma.

Dental trauma is a type of head trauma. It is essential that the dentist be able to assess the gross neurological status of the child presenting with head injury and to recognize acute and delayed signs of nerve injury. Time does not permit the dentist a leisurely review of necessary skills at the time of an emergency visit. He or she must be prepared in advance with a consistent and simple approach for the management of head trauma in children. Time of entry into care is critical to the prognosis.

Child↗