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Biomedical subjects

R C Caruso

Publications and source records attributed to R C Caruso.

31 records · Page 2Linked to original sources
PubMed1989

Attenuating effects of diazepam on the electroretinogram of normal humans.

Response/log I curves were obtained under conditions of dark-and light-adaptation in seven normal male volunteers. For each subject, a baseline electroretinogram (ERG) was recorded. In the same afternoon, a second ERG was obtained after 0.05 mg/kg diazepam, and a third ERG was recorded following 0.10 mg/kg diazepam. Under conditions of dark-adaptation, the following dose-dependent changes were identified: 1) Diazepam attenuated the rod b-wave peak amplitude and increased its implicit time; 2) The dark-adapted longer wavelength cone a-wave and 'blue cone' b-wave showed an increased implicit time; 3) All oscillatory potentials showed an increased implicit time. Under conditions of light-adaptation, dose-dependent decreases in peak amplitude and delays in implicit time were observed for the a- and b-waves. The effects of diazepam on the human ERG were more profound under conditions of light- than dark-adaptation.

Adult↗
PubMed1988

Spatial contrast sensitivity: effects of age, test-retest, and psychophysical method.

Spatial contrast sensitivity was tested twice in normal subjects from five age groups by using each of two different psychophysical methods. Results obtained by the method of adjustment showed a decline in sensitivity with increasing age at all spatial frequencies. In contrast, the forced-choice procedure yielded results indicating an age-related decline predominantly at high spatial frequencies, with the magnitude of the decline being generally similar to that obtained earlier by a tracking method [Vision Res. 23, 689 (1983)]. The decline that we observed cannot be due to pupillary changes with age, since this factor was controlled. Moreover, we suggest that the high-spatial-frequency decline in contrast sensitivity, although it is comparatively small, is too large to be due to changes in lens density. We therefore suggest that a neural component is responsible. In addition, interactions among the age of the subject, the spatial frequency used, and the psychophysical method used suggest that the method of adjustment should be avoided for age-related studies of vision.

Adult↗
PubMed1987

Chronic eyelid closure and its effect upon the human cone and rod electroretinogram.

The human rod and cone systems have different spectral and adaptive sensitivities. Ganzfeld electroretinogram responses show that chronic eyelid closure, such as extensive symblepharon, can lead to dark-adaptation of the rods but simultaneously permit light-adaptation of the cones of the same eye. This effect is due to the red-filtering properties of the closed eyelid and the differential sensitivity of the two photoreceptor systems to the long wavelengths.

Aged↗
PubMed1986

Abnormal retinal function associated with fenretinide, a synthetic retinoid.

Five patients with basal cell carcinoma received fenretinide. Two patients while receiving the drug had evidence of abnormal rod photoreceptor function that reversed rapidly on cessation of therapy. We speculate that fenretinide may interfere with the binding of vitamin A to opsin or with the transport of vitamin A.

Adult↗
PubMed1986

Long-term ocular manifestations in nephropathic cystinosis.

Eight nephropathic-cystinotic patients having undergone renal transplantation seven to 14 years previously were studied. Serious ocular complications were noted in four of the eight cases not previously reported. These included posterior synechiae, deposition of crystals on the anterior lens surface, and decreased visual acuity accompanied by impaired visual function, as measured by psychophysical and electrodiagnostic tests when possible.

Adolescent↗
PubMed1986

Electroretinographic findings in the mucopolysaccharidoses.

The degree of retinal involvement of 20 patients (ages 3-21) with mucopolysaccharidosis (MPS) types I, II, and III was assessed using electroretinography (ERG) under standardized conditions. ERG evidence of retinal dysfunction ranged from none to severe in MPS I and II, and from moderate to severe in MPS III. The ERG abnormalities were common to all three types of MPS, and showed the pattern seen in rod-cone degenerations, where the rod-mediated responses are more severely affected than the cone-mediated responses. The ophthalmoscopic signs were less striking than the electrophysiologic findings, and were usually restricted to mild changes of the retinal pigment epithelium.

Adaptation, Physiological↗
PubMed1984

Spatial contrast sensitivity. Importance of controlling the patient's visibility criterion.

Clinical spatial contrast sensitivity measurements are typically made using psychophysical methods that do not specify the response criterion being used by the patient in judging grating visibility. Results of this report show the necessity of such methods for (1) maximizing detectability of early contrast sensitivity deficits by minimizing normal sample variance, and (2) ensuring that changes in an individual's contrast sensitivity reflect changes in vision and not simply fluctuations in the patient's criterion for judging grating visibility.

Adult↗
PubMed1984

Hyperprolactinemia, amenorrhea, and galactorrhea. A retrospective assessment of twenty-five cases.

The syndrome of hyperprolactinemia, galactorrhea, and amenorrhea is frequently caused by a pituitary tumor. Transsphenoidal surgical removal is often advocated for microadenomas, tumors smaller than 10 mm, to prevent the progression of these small adenomas into large tumors. Because no strong evidence indicates that microadenomas naturally progress to macroadenomas, we studied 25 women who had had hyperprolactinemia, amenorrhea, or galactorrhea for a mean duration of 11.3 years. Their mean initial prolactin level was 225 ng/mL (normal, less than 36 ng/mL). Of 22 patients presenting with amenorrhea, 7 resumed menses spontaneously. Galactorrhea resolved completely in 6 of the 19 patients with this disorder. Only 1 patient had progression of a sellar abnormality, and this was slight. Visual fields remained full in all patients, and basal adrenal and thyroid functions remained normal. The mean prolactin level was 155 ng/mL at the reevaluation (p less than 0.01, initial versus reevaluation levels). Hyperprolactinemia apparently has a benign clinical course in most women, and we advocate a conservative approach to management of this disorder.

Adenoma↗
PubMed1983

Non-fluorescent dye staining of primate blue cones.

The intravitreal injection in macaque retina of the fluorescent dye Procion yellow can selectively label a specific cone population whose eccentricity distribution and angular separation are consistent with those of the blue-sensitive cones of human and non-human primate retinas. Because at the concentrations used the dye is poorly visible in conventional light microscopy, fluorescence microscopy is required for the observation of the stained cones. In this paper we describe several alternative methods for the staining of blue cones in primate retina, staining that can be visualized in conventional light microscopy and, with some methods, electron microscopy.

Animals↗
PubMed1983

Effect of artificial central scotoma on the spatial contrast sensitivity of normal subjects.

Spatial contrast sensitivity was measured in normal subjects with and without a retinally stabilized artificial scotoma (either circular or rectangular), which precluded foveal vision. Our results indicate that the type of contrast sensitivity loss obtained (predominantly high frequency or overall) depended on temporal factors associated with grating presentation. A predominantly high frequency loss was obtained when grating contrast was turned on and off gradually. An additional low frequency difference was obtained when grating contrast was turned on and off abruptly.

Adult↗