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Biomedical subjects

D Weinberger

Publications and source records attributed to D Weinberger.

At least 19 recordsLinked to original sources
PubMed1992

Pigmented epithelial tumours of the conjunctiva.

Two out of 60 conjunctival epithelial tumours reviewed between 1973 and 1989 were found to be pigmented. One tumour was a pigmented papilloma and the other a pigmented squamous cell carcinoma. The melanin pigment was found in epithelial tumour cells as well as in macrophages, dendritic melanocytes, and Langerhans cells. The distinction between the latter two types of cells was possible in one of the tumours only. Both tumours were found in dark-skinned white patients without any evidence of conjunctival acquired melanosis.

Adult↗
PubMed1990

The treatment of foveal central serous choroidopathy by krypton red laser.

We present 24 patients with recent foveal central serous choroidopathy. Only those in whom the leakage site was located within a radius of 250 microns from the foveal center were included in this study. All patients were treated with the krypton red laser (647 nm) within a week of the clinical diagnosis. At the end of the follow-up, 70.8% of the patients had a visual acuity of 6/8.5 or better, and an overall visual improvement was found in 83.3%. In 90% of the patients whose vision improved, significant absorption of subretinal fluid was seen within three weeks and in 10% within four weeks. No evidence of any macular pathology complicating the laser treatment was found at the end of the follow-up period of at least 36 months.

Adult↗
PubMed1990

Magnetoelectric stimulation of human motor cortex: normal values and potential safety issues in spinal cord injury.

Upon magnetoelectric stimulation (MES) of the motor cortex, maximal amplitude and minimal latency of compound muscle action potentials were recorded for four limbs in 20 able-bodied volunteers after ten sequential stimulations. The ratio of maximal cortical to maximal peripheral compound muscle action potential was calculated. Standard statistical parameters were calculated for values from each limb. A paired t-test revealed a statistically significant difference in lower extremity side-to-side amplitude. Regression analysis of patient height vs upper extremity and lower extremity latency demonstrated a strong correlation: r = .720 and r = .601, respectively. A pendulum model demonstrated that a miniscule amount of energy is imparted onto metallic fixation devices by the magnetic coil, but no significant paraspinal activity could be measured in any of five volunteers upon stimulation of the motor cortex. This study has established a normal MES data base that might be useful in evaluating spinal cord injured patients. It has also demonstrated that initial safety concerns about the use of MES in this population are likely unfounded.

Adult↗
PubMed1989

Air travel with intraocular gas. I. The mechanisms for compensation.

The absolute intraocular pressure of the gas-containing eye of a rabbit fell with the fall in cabin pressure during a simulated airplane ascent but lagged behind. The lag was manifested clinically as a relative rise in transscleral pressure. The amount of lag depended on the amount of gas in the eye at takeoff. As there is no significant transfer of gas out of the eye during the ascent, the fall in absolute intraocular pressure could only be mediated by expansion of the bubble. The enabling mechanisms for expansion are choroidal compression, scleral expansion, and accelerated aqueous outflow.

Aerospace Medicine↗
PubMed1989

Air travel with intraocular gas. II. Clinical considerations.

The patient with a residual intraocular gas volume of 0.6 mL, approximately 10% of the volume of the eye, can compensate for the decrease in cabin pressure as an airplane ascends without a symptomatic rise in intraocular pressure. Larger volumes may be accommodated in aircraft that decompress to less than 8000 ft or that take off from altitudes above sea level. The patient with residual intraocular gas who experiences pain or dimness of vision in an ascending airplane can obtain relief if the cabin altitude is decreased by 2000 ft. This will require a modest adjustment in the altitude of the airplane.

Aerospace Medicine↗
PubMed1989

Threshold sensitivity tests in various ocular diseases.

The threshold sensitivity visual-field test is one of the most accurate ways to detect ocular disorders. The indications for utilization of this device in the detection and follow-up of many diseases other than glaucoma and neuro-ophthalmologic disorders can be expanded.

Adolescent↗
PubMed1989

Idiopathic bilateral branch-artery occlusion in a young woman.

An unusual case of a 17-year-old woman with bilateral branch-artery occlusion is presented. A thorough clinical and laboratory investigation showed no evidence of any abnormality, which was also not found during a follow-up period of three years. The obstruction occurred in both eyes within a period of ten months. The differential diagnosis of branch-artery occlusion in the young is discussed.

Adolescent↗
PubMed1988

Instability of leukocyte aggregation: lack of evidence for leukoembolization during various states of inflammation.

This study centers on the question of whether the phenomenon of leukocyte aggregation, which is typical to inflammatory conditions, is pathogenic per se. We examined patients and laboratory animals in whom the presence of aggregated leukocytes in the peripheral blood was documented by direct visualization and where, despite the presence of aggregated leukocytes, neither the patients nor the laboratory animals showed clinical or pathological evidence for leukoembolization. Our in vitro findings about the reversibility of the phenomenon of leukocyte aggregation help to explain the above-mentioned observations as well as the well-known daily clinical experience that, despite complement activation and other aggregatory stimuli, there is no clinical or pathological evidence for leukoembolization.

Aged↗
PubMed1988

Pseudophakic and aphakic pupillary block.

Fifteen eyes of 14 patients who underwent cataract extraction surgery with or without lens implantation developed pupillary block. Six lenses were of the anterior-chamber type, two of the posterior-chamber, and four of the iris-clip Binkhorst type; three were simple aphakic eyes. Ocular hypertension was present in 12 eyes; while in three eyes, the pupillary block was detected by biomicroscopic examination. In order to relieve the block, we performed one of the following three procedures: laser (yttrium aluminum garnet (YAG), argon, or krypton) iridotomy, YAG laser photodisruption of the anterior vitreous face, or pars plana vitrectomy.

Adolescent↗
PubMed1988

The retinal effects of copper vapor laser exposure.

The copper vapor laser is a pulsed gas laser which emits energy in two wavelengths simultaneously: 510.6 nm (green) and 578.2 nm (yellow). Each pulse has a duration of 15 nsec, maximal energy of 3 mJ and a peak power of more than 100 kW. It is a variably high repetition rate laser, in the range between 1 kHz and more than 20 kHz. We studied its interaction with the rabbit retina, while using two different repetition rates, 4 kHz and 18 kHz. The histological analysis of the lesion produced by 4 kHz repetition rate showed undesired retinal effects, similar to those caused by other pulsed lasers. On the other hand, the histological examination of the lesion produced by the 18 kHz repetition rate showed a desired coagulation effect, limited to the outer retinal layers, and comparable to a lesion produced by a continuous wave (CW) laser.

Animals↗
PubMed1987

Computerized visual field and choroidal malignant melanoma.

We present a case report of suspected retinal malignant melanoma that was followed up with a threshold sensitivity visual field test. The correlation between computerized visual fields as used in proving retinal function disabilities and other tumor-growth diagnostic tools is discussed.

Aged↗
PubMed1987

Implantation growth of an iris melanocytic lesion simulating a ciliary body melanoma.

A 59-year-old woman had a sectorial pigmented iris tumor in her right eye and was found to have secondary glaucoma unresponsive to medical therapy. Gonioscopy revealed a satellite tumor in the inferior chamber angle, which we suspected to be a ciliary body melanoma. Subsequently, both lesions were removed completely by superior total and inferior partial iridocyclectomy. Histologic examination disclosed a spindle cell nevus with surface plaque associated with a borderline epithelioid cell nevus. This case is an example of unexpected clinical findings that may be encountered in any iris melanocytic lesion, benign or malignant, and the consequent problems of diagnosis and management.

Ciliary Body↗
PubMed1986

Long-term results of cryotherapy for active stages of retinopathy of prematurity.

Between 1976 and 1980, retinopathy of prematurity (ROP) stage III (moderate) (fibrovascular proliferation) developed in 29 eyes (confluent fibrovascular proliferation of 3 clock hours in extension) of 17 preterm babies. The eyes were treated by cryopexy to the avascular retina. Analysis of the visual function and anatomic results in these eyes, five to eight years postoperatively, revealed very good visual function and only a few anatomic abnormalities. Comparison of these eyes with those of two groups of age- and birth-weight-matched preterms (one with less severe ROP, not treated by cryopexy, and the other with no ROP) showed that the degree of myopia was significantly higher in the cryotreated group. Although not statistically significant, there was a higher incidence and a greater degree of astigmatism in this study group.

Cicatrix↗
PubMed1986

Corneal hypoaesthesia in asymptomatic familial distichiasis.

A 3-year-old child, his mother, and his uncle were found to have asymptomatic distichiasis accompanied by corneal hypoaesthesia. Slit-lamp examination of the mother and her brother revealed normal corneas, but bilateral punctate epithelial staining was found in the child. In addition the child suffered from corneal erosion in his left eye due to decreased tear secretion after left occipital craniotomy and C1 laminectomy.

Adult↗
PubMed1985

Optical properties of the sclera.

A relationship between the structure of the sclera and its light scattering properties is proposed. The relative optical density as a function of wavelength in the infrared was measured for three sclera and a good correlation with the predicted function was found. The angular distribution of the scattered light at 632.8 nm as well as the degree of polarisation of the scattered light at zero angle was measured for three sclera; from these results the total transmission of the sclera was determined.

Collagen↗