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Biomedical subjects

D J Derlacki

Publications and source records attributed to D J Derlacki.

41 records · Page 3Linked to original sources
PubMed1988

Rod and cone dysfunction in carriers of X-linked retinitis pigmentosa.

Carriers of X-linked retinitis pigmentosa were studied using electroretinographic and psychophysical procedures. Under both dark- and light-adapted (cone-isolated) conditions, electroretinogram (ERG) a-waves of carriers were reduced in amplitude but normal in implicit time, whereas b-waves were reduced in amplitude and delayed in implicit time. Reductions in b-wave amplitudes of the carriers as a group were equivalent for the rod and cone systems. Luminance-response functions for both dark-adapted and cone-isolated b-waves were fit by the Naka-Rushton equation and demonstrated a selective reduction of Rmax; the semi-saturation constant (K) and the slope parameter (n) were normal. Electroretinograms recorded using the brightest stimulus flashes were most effective at distinguishing carriers from normals. Absolute thresholds of the carriers were elevated significantly across the central 40 degrees of the visual field. As a group, the threshold elevations of the carriers were approximately equal for the rod and cone systems.

Adult↗
PubMed1987

Psychophysical and electroretinographic findings in X-linked juvenile retinoschisis.

We compared psychophysical and electroretinographic test results of four patients with X-linked juvenile retinoschisis who had clinically apparent lesions isolated to the foveal area. The b-wave of the flash electroretinogram was selectively reduced, while the a-wave was within the normal range. Oscillatory potentials generated by either the rod or cone systems were markedly reduced. Absolute thresholds outside the fovea were either normal or only moderately elevated, indicating that the sensory neural pathways were, by and large, operating with limited dysfunction. Therefore, the oscillatory potentials do not directly reflect, to any appreciable extent, the function of bipolar or ganglion cells. Finally, a sequence of pathologic events is proposed for X-linked juvenile retinoschisis that initiates with Müller cell dysfunction.

Adolescent↗
PubMed1987

Visual acuity loss in patients with Stargardt's macular dystrophy.

Ninety-five patients with Stargardt's macular dystrophy were appraised for visual loss with age by both life-table analyses and cross-sectional procedures. The probability of maintaining a visual acuity of 20/40 or better in at least one eye was 52% by age 19, 32% by age 29, and 22% by age 39. In the population studied, once a patient's visual acuity dropped below 20/40, it tended to decrease rapidly and stabilize at 20/200. Fluorescein angiograms obtained on 64 of the 95 patients showed a "dark choroid" in 55 (85.9%). This finding, therefore was present in the majority of the patients, although its absence does not rule out Stargardt's macular dystrophy.

Actuarial Analysis↗
PubMed1985

The versatility of presculptured homograft incus prostheses.

A twelve-year experience with banked homograft ossicles has developed into a system of presculptured incus allografts adapted for the correction of many ossicular defects encountered in tympanoplasty and revision stapes surgery. The standardized preparation of a number of variations of modeled incus prostheses for an operating room bank by a well-trained ear homograft laboratory technician has been an effective and time-saving technique.

Ear Ossicles↗