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Biomedical subjects

D J Coleman

Publications and source records attributed to D J Coleman.

At least 109 records · Page 6Linked to original sources
PubMed1984

Perfluoropropane gas in the management of proliferative vitreoretinopathy.

Perfluoropropane (C3F8), an expanding fluorinated hydrocarbon gas, was used as an adjunct to vitreous surgery in the management of 18 patients with retinal detachment complicated by proliferative vitreoretinopathy. Ten patients had reattached retinas six months after disappearance of the gas. The average intraocular longevity of the gas in successful cases was 92 days; that in failed cases was 62.7 days. This difference was not statistically significant. However, internal retinal tamponade by longer-lasting gases appears to increase the rate of retinal reattachment in the surgical management of proliferative vitreoretinopathy.

Eye Diseases↗
PubMed1983

Computerized ultrasonic tissue characterization of ocular tumors.

Mathematical evaluation techniques to derive the calibrated power spectrum of reflected ultrasonic echoes from ocular tumors can be used with a clinical computer system to objectively classify malignant melanoma and metastatic carcinoma of the eye. Sets of spectral data provide a reproducible standard for classification that closely approximates the Callender system used in histologic classification. We used spectral data with a computer data library to separate spindle B malignant melanomas (20 tests in 17 patients) from mixed-epithelioid melanomas (17 tests in 13 patients) and to identify metastatic carcinoma (20 tests in 17 patients) with approximately 98% reliability. Tissue structures can be acoustically stained in B-mode images to define the specific anatomic and structural properties that provide the acoustic differentiation. These data are obtained under in vivo conditions and allow a noninvasive classification of tumors in a way not previously possible, aiding in the definitive diagnosis of ocular tumors, as well as in the planning and monitoring of treatment.

Analysis of Variance↗
PubMed1983

Use of an intraocular gas tamponade to find retinal breaks.

We used the receding meniscus of an intraocular bubble being absorbed or the advancing meniscus of an expanding bubble to find the levels of retinal breaks in five patients with retinal detachments in which the breaks could not be found by the usual examination techniques. When we used a receding meniscus, the subretinal fluid was drained and the volume replaced by a perfluorocarbon gas calculated to fill the eye below the probable level of the retinal break. The bubble closed the break and maintained reattachment until the gas was absorbed. The level of the meniscus when redetachment first occurred indicated the level of the break. When we used an advancing meniscus, small amounts of perfluorocarbons were injected without drainage of subretinal fluid. As the gas bubble expanded it reattached the retina from above downward. When the bubble covered the retinal break, it tamponaded it and the remaining fluid absorbed within hours. The level of the meniscus when the retina became reattached marked the level of the retinal break.

Adult↗
PubMed1983

Human sympathetic ophthalmia. An analysis of the inflammatory infiltrate by hybridoma-monoclonal antibodies, immunochemistry, and correlative electron microscopy.

A case of human sympathetic ophthalmia, enucleated after surgical trauma, was studied by means of hybridoma-derived monoclonal antibodies, histochemistry, and transmission electron microscopy. The choroidal infiltrate was composed predominantly of T-lymphocytes of the suppressor/cytotoxic subset (OKT8+); only 5% of the cells were immunoglobulin-producing B-lymphocytes (kappa or lambda light chain positive), thereby explaining the well-known paucity of plasma cells in the infiltrate. The epithelioid cells and phagocytic histiocytes in the choroid were la+ and OKM1+, antigenic determinants specific for bone marrow-derived monocytes, and their cytoplasms exhibited histochemical reactivity for alpha-1-antichymotrypsin and lysozyme. Ultrastructurally, the choroidal epithelioid cells contained single melanin granules in the cytoplasm, but these were membrane-bound and frequently associated with lysosomal material, features militating against these cells being transformed choroidal melanocytes. By means of immunologic and ultrastructural analysis, the Dalen-Fuchs nodules were found to be composed of a mixture of histiocytes (la+ and OKM1+) and depigmented retinal pigment epithelial cells (la- and OKM1-); the latter cells focally formed desmosomes and displayed inclusions of lipofuscin. Scattered within the Dalen-Fuchs nodules were small numbers of T-lymphocytes of the suppressor/cytotoxic subset. We have concluded that the uveitis and retinal pigment epithelial changes are mediated by a T-cell, delayed hypersensitivity pathogenetic mechanism (cell-mediated immunity), possibly directed at surface membrane antigens that may be shared by photoreceptors, retinal pigment epithelial cells, and choroidal melanocytes.

Animals↗
PubMed1983

Theoretical framework for spectrum analysis in ultrasonic tissue characterization.

An analytic model is described for application in ultrasonic tissue characterization. The model is applicable to clinical broadband pulse echo systems. It treats spectra derived from received echo signals and relates them to physical tissue properties. The model can be applied to deterministic tissue structures (e.g., retinal detachments, larger blood vessels, and surface layers of the kidney) and to stochastic tissue structures (e.g., various tumors). The beam patterns included in the model are those generated by focused transducers typically used in high-resolution clinical ultrasound. Appropriate calibration procedures are also treated; these are needed for interpretation of absolute spectral parameters. The results obtained with the analytic model have been used to design a digital processing system and the associated techniques which are now being applied during examinations of the eye and abdominal organs. The results have proven useful in interpreting data from various types of tissues. To illustrate the application of these results, representative clinical data, obtained from the digital system, are presented for two types of tissue architectures. The first case is a detached retina representing a deterministic structure characterized by well-defined thickness and reflection coefficients. The second case is asteroid hyalosis and represents a stochastic entity in which the positions of small scattering particles are best described in statistical terms, and characterization is accompanied by means of normalized power spectra.

Eye Diseases↗
PubMed1982

Early vitrectomy in the management of the severely traumatized eye.

In a series of 112 consecutive patients who underwent vitrectomy because of severe penetrating ocular trauma, good visual recovery (6/12 [20/40] or better) was achieved in 15 of 23 patients (65%) who underwent surgery within 72 hours of the injury (Group 1), in seven of 14 patients (50%) who underwent surgery three to ten days after injury (Group 2), in eight of 22 patients (36%) who underwent surgery ten to 14 days after injury (Group 3), in two of five patients (40%) who underwent surgery 14 to 30 days after injury (Group 4A), and in 17 of 48 patients (35%) who underwent surgery more than 40 days after injury (Group 4B). Functional vision (6/12 [20/40] to counting fingers) was achieved in three of 23 patients (13%) in Group I, five of 14 patients (36%) in Group 2, six of 22 patients (27%) in Group 3, two of five patients (40%) in Group 4A, and in 22 of 48 patients (46%) in Group 4B. These data indicated that definitive early surgical intervention, including vitrectomy, should be considered as part of the primary repair or performed within 72 hours of the injury. Early surgery provides a statistical better prognosis for good visual recovery than a delay of three to 14 days or longer.

Eye Injuries↗
PubMed1980

Ultrasonically accelerated resorption of vitreous membranes.

A noninvasive procedure was used to treat membranes within the vitreous with controlled exposure to focused high-intensity ultrasound in rabbit eyes. Membranes were created by injecting small quantities of platelet-rich plasma into the vitreous of the intact globe of anesthetized rabbits. The average time for untreated membranes (controls and shams) to be resorbed was 34 days, whereas the average time to total resorption of membranes treated with ultrasound was 21 days. This comparison showed that high-intensity ultrasound was effective in accelerating the resorption of this type of vitreous membrane. This ultrasound technique is totally noninvasive and can be used without damage to other ocular tissues. Although this animal model departs in some respects from human vitreous membranes, eventual clinical applications are indicated in selected cases where vitrectomy must be delayed or is contraindicated. Noninvasive disruption of vitreous membranes by therapeutic ultrasound offers great promise for reducing the visual limitations produced by such membranes, and eliminating the sequence of disease leading to permanent visual loss.

Animals↗
PubMed1979

Vitreous wick syndrome.

A 67-year-old man had vitreous wick syndrome after an uncomplicated intracapsular cataract extraction with a sector iridectomy in the left eye. The intraocular infection cleared with antibiotic therapy including intravitreal antibiotic injection, but a residual anterior cyclitic membrane and shallow anterior chamber persisted. An anterior vitrectomy was performed later in the course of treatment after the intraocular infection subsided, to relieve the shallow anterior chamber, prolonged hypotony, and ciliary body detachment. Final visual acuity was 6/15+(20/50+) in the left eye.

Aged↗
PubMed1979

In vivo choroidal thickness measurement.

We developed a system that permits exceptionally accurate measurements of human choroidal thickness in vivo by means of ultrasound. With minicomputer techniques, the complementary functions of the time and spectral domains of reflected sound can be used to permit measurements accurate to less than 20 mu at 10 MHz center frequency. Even more accuracy can be obtained with higher center frequencies. Choroidal thickness has been found to exceed that previously reported, with typical values of 420 mu found at the posterior pole. Even greater values are seen in regions outside the macula.

Cornea↗
PubMed1979

Ultrasonically guided needle biopsy and cytologic diagnosis of solid intraocular tumors.

Six solid intraocular tumors were reliably diagnosed by needle biopsies and cytologic examination of the aspirates. All of the tumors had an unusual clinical or diagnostic feature that raised the possibility of a non-melanomatous tumor. Two intraocular lesions that were obscured by opaque media or a retinal detachment were successfully biopsied under B-scan ultrasonographic guidance of the needle. Cytodiagnosis of narrow spindle B, plump spindle B, and eipthelioid cell types, as well as one case of Coats' disease, was possible and correlated closely with the predominant cell types comprising the lesions discovered on histopathologic examination of the globes that were enucleated. The ocular tissues were not significantly disturbed and hemorrhage was not a serious problem. Details of the biopsy and cytologic techniques, the major clinical indications, for the procedure, and the authors' belief that the procedure is not likely to produce local seeding or extraocular metastasis in cases of melanoma are presented and discussed. Considerable profit may attend the use of this technique for the diagnosis of possible metastatic lesions and tumors of the ciliary body. The technique, however, should not be routinely employed and should be restricted to extremely difficult diagnostic problems.

Adult↗
PubMed1979

Immersion ultrasonography: simultaneous A-scan and B-scan.

In eyes with opaque media, ophthalmic ultrasound provides a unique source of information that can dramatically affect the course of patient management. In addition, when an ocular abnormality can be visualized, ultrasonography provides information that supplements and complements other diagnostic testing. It provides documentation and differentiation of abnormal states, such as vitreous hemorrhage and intraocular tumor, as well as differentiation of orbital tumors from inflammatory causes of exophthalmos. Additional capabilities of ultrasound are biometric determinations for calculation of intraocular lens implant powers and drug-effectiveness studies. Maximal information is derived from ultrasonography when A-scan and B-scan techniques are employed simultaneously. Flexibility of electronics, variable-frequency transducers, and the use of several different manual scanning patterns aid in detection and interpretation of results. The immersion system of ultrasonography provides these features optimally.

Carcinoma↗