The antimuscarinic activity of optical isomers of tropicamide were compared on the isolated rabbit iris sphincter. The increasing concentrations of both the (--)- and (+)-isomer shifted the dose-response curve of carbachol to the right in a parallel fashion. The competitive reversible muscarinic blocking effects of both isomers were confirmed by pA2 plots. The pA2 values from the nonpigmented i...

We examined 296 patients with a history of melanoma and 145 controls for the presence of atypical (dysplastic) nevi. We found that 34% of patients with melanoma and 7% of controls had clinically atypical (dysplastic) nevi. Patients and controls with atypical (dysplastic) nevi had more nevi than the subjects without. The number of nevi varies negatively and significantly with age (r = 0.37, P le...

Waardenburg syndrome (WS) is characterized by the association of pigmentation abnormalities, including depigmented patches of the skin and hair, vivid blue eyes or heterochromia irides, and sensorineural hearing loss. However, other features such as dystopia canthorum, musculoskeletal abnormalities of the limbs, Hirschsprung disease, or neurological defects are found in subsets of patients and ...

The Chediak-Higashi syndrome (CHS) occurs in mammals, including humans and cats. The CHS is characterized by decreased oculocutaneous pigmentation, enlarged cytoplasmic granules, increased susceptibility to infections, and a hemorrhagic tendency. Ocular anomalies include pale irides and albinotic or subalbinotic fundi. Cats with CHS also have photophobia and prolonged postrotatory nystagmus. Si...

A dominantly inherited syndrome associated with hypopigmentation, heterochromia irides, colobomatous eyes and bilateral hearing loss has been ascertained in Fleckvieh cattle (German White Fleckvieh syndrome). This syndrome has been mapped to bovine chromosome (BTA) 22 using a genome-wide association study with the bovine high density single nucleotide polymorphism array. An R210I missense mutat...

Extensive experience with animals has shown that it is possible to irradiate the iris with a ruby laser without damage to the cornea, lens, or retina (Hallman, Perkins, Watts, and Wheeler, I 968, I969). The possible use of a laser to make an iridotomy for therapeutic purposes was appreciated by Flocks and Zweng (i964), and Zweng, Flocks, Kampany, Silbertrust, and Peppers (I964) reported two att...

Many cephalopods exhibit remarkable dermal iridescence, a component of their complex, dynamic camouflage and communication. In the species Euprymna scolopes, the light-organ iridescence is static and is due to reflectin protein-based platelets assembled into lamellar thin-film reflectors called iridosomes, contained within iridescent cells called iridocytes. Squid in the family Loliginidae appe...

Two papers in the current issue, one from Pollack, Dotan, and Oliver of Israel and the other from Cunliffe and colleagues of Cambridge, deal with the effects of cataract surgery on diabetic retinopathy and its complications. All ophthalmologists are aware that there are possible extra hazards when cataract extraction has to be done in the presence of diabetic retinopathy, but in view of the fac...