Role of hydrogen bonding in general anesthesia.

The importance of hydrogen bonding in determining the potency of a general anesthetic is controversial. In order to investigate the role of hydrogen bonding further, we have used a multiple linear regression approach to quantify the relative importance of various physical properties of an anesthetic molecule (i.e.

Color Doppler imaging provides accurate assessment of orbital blood flow in occlusive carotid artery disease.

Color Doppler imaging was used to evaluate the hemodynamics of the ophthalmic vasculature in a case of complete internal carotid artery occlusion. This procedure, which allows rapid, noninvasive imaging, showed a partial ophthalmic artery obstruction with absent flow in the central retinal artery, central retinal vein, and nasal posterior ciliary arteries. Although altered perfusion of the retinal vessels may be evaluated clinically, assessment of blood flow in the ophthalmic and ciliary arteries previously could be evaluated only indirectly by intravenous fluorescein angiography.

Color Doppler imaging of the eye and orbit. Technique and normal vascular anatomy.

Color Doppler imaging is a recent advance in ultrasonography that allows simultaneous two-dimensional imaging of structure and blood flow to be performed. Doppler information is superimposed in color over a conventional gray-scale ultrasound image. Using this technique, we examined 40 normal eyes.

Color Doppler imaging. A new noninvasive technique to diagnose and monitor carotid cavernous sinus fistulas.

Color Doppler imaging is a recent development in ultrasonography that allows for simultaneous two-dimensional structural imaging and Doppler evaluation of blood flow. With this technique, one patient with a traumatic carotid cavernous sinus fistula and two patients with spontaneous dural cavernous arteriovenous malformations were evaluated. Color Doppler imaging demonstrated a dilated superior ophthalmic vein with arterialized blood flow in all three patients.

Probing the molecular dimensions of general anaesthetic target sites in tadpoles (Xenopus laevis) and model systems using cycloalcohols.

1. The series of cycloalcohols C6, C7, C8 and C10 have been used to probe the molecular dimensions of a variety of general anaesthetic target sites. 2.

Modulation of the general anesthetic sensitivity of a protein: a transition between two forms of firefly luciferase.

The activities of most proteins are relatively insensitive to general anesthetics. A notable exception is firefly luciferase, whose sensitivity to a wide range of anesthetic agents closely parallels that of whole animals. We have now found that this sensitivity can be controlled by ATP.

An anaesthetic-activated potassium channel.

We have discovered a novel potassium current in an identified molluscan neuron which is activated at surgical levels of volatile general anaesthetics. The current is not significantly voltage-gated and persists for as long as the anaesthetic is present. The anaesthetic response is completely reversibly and saturates at low anaesthetic partial pressures.

Color Doppler imaging in the management of intraocular tumors.

Forty-four intraocular mass lesions were studied using a new, non-invasive ultrasound technique known as color Doppler imaging (CDI). This technique displays color-encoded Doppler flow information throughout a two-dimensional gray scale image thus providing selective analysis of Doppler spectra in small vessels using pulsed Doppler. Abnormal Doppler shifts were demonstrated within 39 neoplastic lesions studied, but Doppler shifts could not be detected in three tumor-simulating lesions.

Cystic adenoma of the pigmented ciliary epithelium. Clinical, pathologic, and immunohistopathologic findings.

A 51-year-old white man was found to have a deeply pigmented mass in the ciliary body and peripheral choroid of his right eye with an associated vitreous hemorrhage. Although the tumor appeared to be a ciliochoroidal melanoma, a melanocytoma and adenoma of the pigment epithelium also were considered in the differential diagnosis. The tumor was removed by a large partial lamellar sclerocyclochoroidectomy.

Mechanisms of general anesthesia.

Although general anesthetics are often said to be nonspecific agents, it is likely that they act at a much more restricted set of target sites than commonly believed. The traditional view has been that the primary targets are lipid portions of nerve membranes, but recent evidence shows that the effects on lipid bilayers of clinically relevant levels of anesthetics are very small. Effects on most proteins are also small, but there are notable examples of proteins that are extremely sensitive to anesthetics and mimic the pharmacological profile of anesthetic target sites in animals.

Mucinous adenocarcinoma metastatic to the iris, ciliary body, and choroid.

A 67-year-old woman presented with signs of severe intraocular inflammation and secondary glaucoma. The initial diagnosis was uveitis, and an anterior chamber paracentesis with cytological study of the aspirate failed to establish an aetiological diagnosis. After three trabeculectomies had failed to control the intraocular pressure, the blind eye was enucleated.

Effects of general anesthetics on the bacterial luciferase enzyme from Vibrio harveyi: an anesthetic target site with differential sensitivity.

The effects of a diverse range of 36 general anesthetics and anesthetic-like compounds on a highly purified preparation of the bacterial luciferase enzyme from Vibrio harveyi have been investigated. Under conditions where the flavin site was saturated, almost all of the anesthetics inhibited the peak enzyme activity and slowed the rate of decay. However, a small number of the more polar agents only inhibited at high concentrations, while stimulating activity at lower concentrations.

Colour Doppler imaging in the demonstration of an orbital varix.

Colour Doppler imaging (CDI) is a recent development in ultrasonography. It allows simultaneous two-dimensional structural imaging and Doppler evaluation of blood flow. Quantitative information on flow velocity is obtained by pulsed Doppler spectral analysis, the colour information being used to choose the vessel of interest.

Malignant melanoma associated with melanocytoma of the optic disc.

A 61-year-old white man underwent enucleation because of progressive growth of a pigmented epipapillary tumor that was diagnosed 9 years earlier as an optic nerve and juxtapapillary melanocytoma. Histopathologic studies showed the tumor was a malignant melanoma of the optic disc and juxtapapillary retina and choroid. Foci of typical melanocytoma cells were within the tumor.

Postsurgical hematic cyst simulating a conjunctival melanoma.

A 75-year-old man had undergone bilateral intracapsular cataract extraction and then a scleral buckling procedure for an aphakic retinal detachment in the right eye. He presented 15 years later with a dark brown mass in the superior fornix of his right eye. On the basis of the clinical findings, the diagnosis of a conjunctival melanoma was considered.

Microphthalmos with colobomatous orbital cyst: clinical, histological, immunohistological, and electronmicroscopic findings.

A case of unilateral microphthalmos with orbital cyst is presented. This rare and severe malformation is a non-hereditary disorder. Pathologically it represents a failure in the closure of the embryonic fissure at the 7-14 mm stage of gestation.

Ciamexone in endocrine orbitopathy. A randomized double-blind, placebo-controlled study.

The influence of ciamexone on the activity and course of endocrine orbitopathy was investigated. Fifty-one patients with active orbitopathy classes II-VI were allocated randomly to two groups: over a period of six months, 26 patients received 300 mg/day ciamexone and 25 patients received placebo tablets. In both groups, prednisolone was administered in addition in the first four weeks.

[Imaging of intraocular and orbital vessels using angiodynography].

Color Doppler imaging (CDI) is a recent advance in ultrasonography. It allows simultaneous two-dimensional structural imaging and evaluation of blood-flow characteristics. The velocity information of the scan is extracted and added to the images as color information.

Changing concepts in the management of retinoblastoma.

For many years the most common treatment for retinoblastoma has been enucleation, generally performed on the affected eye in children with unilateral sporadic disease and on the more severely affected eye in children with bilateral disease. With refinements in conservative treatment methods, however, the affected eye now often may be salvaged and useful vision retained. Emphasizing this trend, we present our current approaches to managing retinoblastoma based on our experience with 324 patients, outlining our indications and pointing out a number of misconceptions about the role of enucleation, photocoagulation, cryotherapy, and radiotherapy in treating this condition.

Myxoma of the orbit: a clinicopathologic report.

A 27-year-old white man developed proptosis of his left eye over a period of 2 years. It was associated with vertical diplopia and displacement of the left globe down and laterally. Ultrasonography showed a cystic mass in the superior orbital region.

Multiple orbital neurofibromas unassociated with von Recklinghausen's disease.

A 58-year-old man with a 10-year history of right periorbital pain treated with multiple analgesics presented with slowly progressive exophthalmos of the right eye. Orbital imaging studies disclosed three separate well-defined tumors, located in the temporal fossa, the intraconal space, and within the floor of the orbit. All three tumors were removed intact and proved on histopathologic evaluation to be localized neurofibromas.

[Ultrasound microscopy findings of artificial lenses].

Acoustic microscopy permits a native, nondestructive and artefact-free analysis of the surface of intraocular lenses with regard to manufacturing defects, biologic cellular and membranaceous layers, and signs of degradation. Furthermore, it enables structures below the surface to be evaluated, so that inclusions, pores, microcracks and zones of deformation can be detected. In addition to performance of a one-dimensional, relative intensity profile of the surface and the corresponding pseudo-3D image, the properties of the materials inside the intraocular lens can be characterized by computerized analysis of the reflected ultrasound energy.

Current treatment of retinoblastoma.

Based on personal experience with 324 children with retinoblastoma who were managed on the Ocular Oncology Service at Wills Eye Hospital between 1974 and 1988, the authors review their current management of this tumor, emphasize common misconceptions in management, and describe the recent research related to the genetics of retinoblastoma. It is pointed out that the optic nerve should not be clamped at the time of enucleation. Photocoagulation should only be used to treat small tumors strictly confined to the retina and it is contraindicated if there is vitreal or choroidal invasion.