Technical Note: A comparison of a novel direct ophthalmoscope, the OptyseTM, to conventional direct ophthalmoscopes

Despite the current popularity of binocular indirect ophthalmoscopy, direct ophthalmoscopes are still commonly used by clinicians for fundus examination. They are considered to be expensive, however, and it has been suggested that this cost can prevent their use by healthcare professionals in developing countries. The Optyse Lens Free Ophthalmoscope is a novel direct ophthalmoscope, without a lens focus system, that allows for comparatively inexpensive manufacture and supply. We compared the clarity of view with the Optyse to that with standard direct ophthalmoscopes, over a sequential cohort of patients with a variety of refractive errors and ocular conditions. The grade of clarity of view with the Optyse Lens Free Ophthalmoscope was less than conventional ophthalmoscopes (Wilcoxon signed rank test, p < 0.0001). This grade of clarity of view was not associated with the ametropia of the ophthalmoscopic observation (Spearman r < or = 0.03, p > or = 0.28) but was with the presence of cataracts (chi2 test, p < 0.0001) with both the Optyse and the conventional ophthalmoscopes. Despite its limitations, the retinal view with Optyse was often within acceptable clinical limits suggesting that this relatively inexpensive ophthalmoscope may have a place when cost prohibits any other type of ophthalmoscope use.     

Powered wheelchair bucking

Using a dummy test driver with a simulated flaccid forearm capable of representing either a large or zero friction condition, six powered wheelchairs were examined for bucking tendencies. In the zero friction condition, bucking was easily induced in 5 of 6 tested wheelchairs. Adding friction to the simulated forearm prevented bucking in all tested wheelchairs but one. Bucking is not simply related to wheelchair performance measures such as speed or acceleration. Sustained bucking corresponds to neutral stability in a speed regulated machine. Changes in natural frequency and damping characteristics are predicted as useful in reducing powered wheelchair bucking.     

Dopamine denervation does not alter in vivo 3H-spiperone binding in rat striatum: implications for external imaging of dopamine receptors in Parkinson's disease

Striatal particulate preparations, both from rats with lesion-induced striatal dopamine (DA) loss and from some striatal dopamine (DA) loss and from some patients with Parkinson's disease, exhibit increased 3H-neuroleptic binding, which is interpreted to be the mechanism of denervation-induced behavioral supersensitivity to dopaminergic compounds. After intravenous 3H-spiperone (3H-SP) administration to rats with unilateral nigral lesions, we found no differences in accumulation of total or particulate-bound 3H-SP in dopamine-denervated compared with intact striata. 3H-SP in vivo binds to less than 10% of striatal sites labeled by 3H-SP incubated with striatal particulate preparations in vitro. Quantitative autoradiography of 3H-SP binding to striatal sections in vitro also failed to reveal any effects of dopamine denervation. 3H-SP bound to striatal sites in vivo dissociates more slowly than that bound to striatal particulate preparations labeled in vitro. Striatal binding properties of 3H-SP administered in vivo are quite different from the same kinetic binding parameters estimated in vitro using crude membrane preparations of striatum. In addition, striatal binding of in vivo-administered 3H-SP is not affected by prior lesion of the substantia nigra, which results in profound ipsilateral striatal dopamine depletion. Thus, behavioral supersensitivity to dopaminergic compounds may not be associated with altered striatal binding properties for dopamine receptor ligands in vivo.     

Nitrates do not affect prostacyclin formation by rat arteries: this is unrelated to increased vascular prostacyclin formation with age

The question of whether vasodilator nitrates act by releasing prostacyclin is controversial. Since the ability of blood vessels to form prostacyclin changes with age, we have investigated whether this may explain the discrepancies in the literature. It does not, since isosorbide dinitrate or glyceryl trinitrate incubated with rat aorta or vena cava from male Wistar rats had little or no effect on the release of prostacyclin, measured as 6-keto-PGF1 alpha. We confirm that the aorta produces substantially more prostacyclin than the vena cava. The arterial production of prostacyclin was greater in rats weighing 350-400 g than in those weighing 116-152 g, but the production by the veins was similar in both groups.     

Mohs micrographic surgery for skin cancers of the neck

The neck is not a common area for a skin cancer to occur. However, when it does occur and extends deeply, careful extirpation is necessary so that vital structures will be identified and, if possible, preserved. The Mohs surgeon can most accurately determine the true extent of malignancies in this area; the head and neck surgeon can best identify and protect important anatomic structures. Together both physicians can achieve the best chance of cure and lessen the complication rate for patients with selected invasive cutaneous tumors of the neck. Future collaborative efforts will undoubtedly be directed toward complete extirpation of deeper tumors of the neck, especially those of the pharynx, hypopharynx, and trachea.     

Histiocytic necrotizing lymphadenitis (Kikuchi's disease)

Histiocytic necrotizing lymphadenitis (Kikuchi's disease) is a benign disorder predominantly of young women who present with cervical adenopathy. It has, on occasion, been misdiagnosed as a malignant neoplasm. Little mention of this condition has appeared in the otolaryngologic literature. A patient with Kikuchi's disease is reported and the pertinent literature is reviewed. Because both the clinical and pathological aspects of Kikuchi's disease are important in establishing the diagnosis, effective consultation between the head and neck surgeon and the pathologist is crucial.