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Biomedical subjects

D M Worthen

Publications and source records attributed to D M Worthen.

At least 19 recordsLinked to original sources
PubMed1985

Fibronectin in human trabecular drainage channels.

Fibronectin, an extracellular glycoprotein, has been shown to be produced by human trabecular cells in culture by our group as well as Polansky and co-investigators. Studies of Rodrigues et al suggested that fibronectin may be one of several glycoproteins found in increased amounts in the corneoscleral trabecular meshwork of glaucomatous eyes. The authors have developed a sensitive immunoassay utilizing avidin-biotinylated enzyme complex (ABC) to detect low levels of fibronectin in frozen sections of human eyes. The authors have used this immunoassay together with a perfusion technique to demonstrate distribution patterns of fibronectin present in human aqueous drainage channels. The authors found that fibronectin is present in larger quantities in the aqueous drainage channels than in the surrounding tissues in 18 eyes from older patients.

Aged↗
PubMed1985

Selective binding affinity of human plasma fibronectin for the collagens I-IV.

The binding of plasma fibronectin to the collagens I, II, and III was greater in a cohort of glaucoma patients. In contrast, binding of plasma fibronectin to collagen type IV was less in 39 glaucoma patients than in any of 3 other diagnostic categories, including 92 patients that were normal, cataract, and glaucoma suspect patients. This observation may have significance in further understanding the control of aqueous outflow resistance in glaucoma and nonglaucoma patients.

Aged↗
PubMed1984

The FDA report on intraocular lenses.

Clinical studies of intraocular lenses (IOLs) as investigational devices have been regulated in the United States by the Food and Drug Administration (FDA) since 9 February 1978. As of August 1982, data have been collected on more than one million IOLs implanted. During the last 12 months of the study, 409 000 IOLs were implanted. Visual acuity of 20/40 or better at one year after surgery was present in 85% of over 45 000 cases reviewed. Increasing patient age, surgical problems, postoperative complications, and adverse reactions were factors that reduced the visual acuity. The current trend in the USA is for implantation of posterior chamber and anterior chamber IOLs.

Cataract Extraction↗
PubMed1983

Trends in cataract surgery and intraocular lenses in the United States.

Cataracts are the second leading cause of blindness in the United States. The rate of cataract surgery has greatly increased in the past several years, in part because of the extensive use of intraocular lenses for aphakic correction. It is estimated that more than 600,000 cataract operations were done in 1982. During a similar period, an estimated 496,000 intraocular lenses were implanted. Thus, more than 70% of all cataract operations in the United States involved intraocular lens implantation. Although iris fixation lenses accounted for 52% of all intraocular lenses implanted in 1978, during the six-month period from July 1982 through January 1983 57% of all implanted intraocular lenses were posterior chamber lenses and 40% were anterior chamber lenses.

Adolescent↗
PubMed1983

Vitreous carbon: a new material for making microtome knives.

The quality of sections obtained by microtomy depends to a large extent on the quality and characteristics of the microtome knife itself. Despite the need for improved microtomy techniques, there have been few significant developments since the introduction of glass and diamond knives in the 1950's. The manufacture of microtome knives from vitreous carbon provides new possibilities for developing both improved methods and improved equipment for specimen sectioning. Vitreous carbon has unique physical properties that lend themselves to the generation of precision cutting edges. Such as edge can be obtained either by breaking a piece of vitreous carbon or by using lapidary techniques. The resultant edge seems well adapted to both thick and thin sectioning. The introduction of vitreous carbon as a sectioning tool offers a significant alternative to metal, glass and diamond knives.

Carbon↗
PubMed1979

An evaluation of iridology.

Iridology is an analysis of health based on examination of the iris of the eye. One hundred forty-three patients had photographs taken of both eyes. Nine-five patients were free of kidney disease, defined as a creatinine level of less than 1.2 mg/dL (mean, 0.8 mg/dL), and 48 had kidney disease severe enough to raise the plasma creatinine level to 1.5 mg/dL or greater (mean, 6.5 mg/dL). Three ophthalmologists and three iridologists viewed the slides in a randomized sequence without knowledge of the number of patients in the two categories or any information about patient history. Iridology had no clinical or statistically significant ability to detect the presence of kidney disease. Iridology was neither selective nor specific, and the likelihood of correct detection was statistically no better than chance.

Adult↗
PubMed1979

Immobilization of viral antigens on filter paper for a [125I]staphylococcal protein A immunoassay: a rapid and sensitive technique for detection of herpes simplex virus antigens and antiviral antibodies.

A new technique is described for the rapid detection and quantitation of herpes simplex virus (HSV) antigens and antiviral antibodies. It involves immobilization of HSV antigens on filter paper discs and subsequent analysis by 125I-labeled staphylococcal protein A (SPA) radioimmunoassay. A specially designed 96-well filtration device is employed which serves both as an incubation chamber and as a filtration manifold. It is rapid, simple, sensitive and specific, and requires only small volumes of antiserum and few target cells. The results may be readily and objectively quantitated. This technique permits the simultaneous assay of a large number of specimens in less than 1 h. Its sensitivity is considerably greater than that of other currently used immunologic techniques, and it is amenable to automation. These characteristics suggest that this [125I]SPA immunofiltration technique may be applicable to the rapid diagnosis of viral infections.

Antibodies, Viral↗
PubMed1979

Argon laser trabeculotomy:long-term follow-up.

A five-year follow-up of argon laser trabeculectomy in a group of 28 male patients with bilateral patients with bilateral primary open-angle glaucoma showed an overall mean pressure drop of 10.3 mm Hg in treated eyes. Twenty percent of the treated eyes had a pressure less than 20 mm Hg up to two years after treatment. No specific laser parameters were associated with pressure lowering. The pressure drop appears more patient dependent than treatment dependent. A randomized clinical trial is suggested.

Adult↗
PubMed1978

Future impact of manpower needs on ophthalmology training programs.

Current projections for ophthalmology manpower needs in the year 2000 suggest that the number of new ophthalmologists trained should be frozen at 500 a year. Factors that would cause a need to train more ophthalmologists would be a shorter workweek or workyear, an increased length of time for each patient visit, universal comprehensive health insurance, an earlier age of retirement, and an increased incidence of eye disease. The factor that would most likely reduce the need for new ophthalmologists would be the transfer of primary eye care delivery to nonophthalmologists. Modulation of resident numbers should be based on peer-judged program quality, not on geography or government edict.

Forecasting↗