Computed tomographic three-dimensional localization and compositional evaluation of intraocular and orbital foreign bodies

A software program designed for the Siemens Somatom DR3 computed tomographic (CT) scanner provides improved diagnosis, localization, and etiologic description of intraocular and orbital foreign bodies. The program allows information to be analyzed in two different display formats. One format is that of multiplanar reconstruction of the eye and orbit, including an "oblique CT cube" image. This format produces an accurate "three-dimensional" display of both in vitro and in vivo intraocular and orbital foreign bodies. The second display format is that of a histogram. Using this analytic mode, nonmetallic intraocular and intraorbital foreign bodies can be differentiated from each other and from metallic foreign bodies, although individual metallic foreign bodies cannot be identified with respect to specific composition. The information provided by these two display formats substantially aids the clinician in the diagnosis and management of foreign bodies located within the orbit, particularly those located within the eye.

Phentolamine-resistant neurogenic constriction occurs in small arteries at higher frequencies

The effect of the alpha 1, alpha 2-antagonist phentolamine (PTA) on neuromuscular transmission and exogenous norepinephrine (NE) was assessed in arteries of diminishing diameter possessing a substantial adventitiomedial junction adrenergic innervation in the rabbit ear, i.e., central ear artery (CEA), unstretched lumen diameter (ULD) approximately equal to 300 microns; main side branch (MSB) off the CEA (ULD approximately equal to 150 microns); and terminal branch (TB) off the MSB (ULD approximately equal to 75 microns). With increasing PTA concentrations, contractile responses to transmural nerve stimulation (TNS) were decreased proportionately less in TB than in MSB and CEA. PTA (4 X 10(-6) M, a competitive antagonist concentration) blocked the tetrodotoxin-sensitive TNS-induced contractions of CEA segments at 2, 4, and 8 Hz. The response at 8 Hz was reduced at least 98% in MSB and 86% in TB. However, responses to 8 Hz were not abolished in MSB and TB until 2 X 10(-5) and 3 X 10(-5) M PTA, respectively. PTA (3 X 10(-5) M) possessed nonspecific depressant properties in addition to its alpha-antagonist properties. We conclude that the sympathetic nervous system influences tone through alpha-adrenoceptors in the CEA and in the MSB and TB at lower frequencies. Responses in the MSB and TB at higher frequencies of nerve stimulation are mediated predominately through alpha-receptors. If the possibility of a nonadrenergic transmitter is discounted, the possibilities that the small PTA-resistant component of the neurogenic response is due to a high concentration of NE acting on alpha-adrenoceptors and/or a high threshold site cannot be distinguished.

Observations on patients with neural-tube defects in a metropolitan hospital clinic: an epidemiological history

A survey of the population of the Spina Bifida Service (107 patients) of Georgetown University Hospital, Washington, D.C., and of a control population in the same hospital revealed that, although situated in an ethnically heterogeneous area, Service patients with a history of neural-tube defects in siblings or family significantly more often had ancestors on both sides from the British Isles than did either isolated cases or the controls. In addition, of 107 families reviewed, nine had more than one affected child, nine had a positive family history for neural-tube defects, and nine of the patients and seven of an estimated total of 220 siblings had an unrelated major birth-defect. These incidences are among the highest published so far. Contrary to other surveys, there was no deficiency of twinning among the sibships, nor of males among the Spina Bifida Service patients. These observations indicate the desirability of studying each population of patients with neural-tube defects in order to provide more realistic counseling and so that clues may be gathered as to the genetic mechanisms and environmental factors which led to the production of such defects.