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Biomedical subjects

C W Yung

Publications and source records attributed to C W Yung.

At least 19 recordsLinked to original sources
PubMed2001

Macular pigment optical density before and after cataract extraction.

PURPOSE: Psychophysical methods of measuring macular pigment (MP) use comparisons of short- and midwave light in the fovea and parafovea to derive optical density estimates. This light must pass through the crystalline lens before absorption by the MPs can occur. The effect of lens absorption on these measures has not been adequately determined. The present study assesses the influence of lens absorption on MP measurements by comparing MP optical density (MPOD) measured before and after cataract extraction. METHODS: MPOD was measured using flicker photometry in free view at 458 nm with a 1 degrees stimulus. Twenty-nine eyes from 24 patients with cataracts sufficiently severe to require cataract extraction were evaluated. RESULTS: In the entire group of 24 patients, the mean (+/-SD) age measured 68.7 +/- 9.5 years, and the mean MPOD measured 0.19 +/- 0.11. For all 29 eyes measured, MPOD averaged 0.206 +/- 0.13 before and 0.18 +/- 0.12 after cataract extraction. MPOD measurements at the two time points (mean 8.1 +/- 4.7 weeks after surgery) were highly correlated (r = +0.58), suggesting that a cataractous lens does not influence the MP measurement technique. CONCLUSIONS: Psychophysical techniques can be used to obtain reliable measurements of MP in elderly subjects, even in those with cataracts. Moreover, differences in retinal illuminance due to varying opaqueness of the crystalline lens do not seem to have a measurable influence on MPOD.

Aged↗
PubMed1997

Spontaneous resolution of an endocapsular hematoma.

PURPOSE: To report a case of endocapsular hematoma that cleared spontaneously without intervention. METHODS: We examined and followed up a 68-year-old man who developed an endocapsular hematoma 2 1/2 years after a standard extracapsular cataract extraction with posterior chamber intraocular lens implantation. RESULTS: After several months without intervention, the endocapsular hematoma completely resolved. CONCLUSIONS: Observation may be a rational treatment option in some patients with endocapsular hematoma.

Aged↗
PubMed1997

Talc embolism: a static retinopathy.

PURPOSE: To document the static nature of crystalline deposits in talc retinopathy. METHOD: Case report. RESULTS: A 38-year-old woman with a remote history of intravenous drug abuse showed the incidental finding of fine, irregularly shaped refractile deposits in the retinal microvasculature. At 2-year follow-up, fundus findings were identical to the initial manifestation with respect to the distribution and position of crystalline deposits in each fundus. CONCLUSION: This case documents the static nature of crystalline deposits in talc retinopathy.

Adult↗
PubMed1996

Retinal blood flow indices in patients infected with human immunodeficiency virus.

AIMS/BACKGROUND: Abnormal blood flow dynamics are believed to contribute to the development of retinal microvascular disease in patients infected with human immunodeficiency virus (HIV). In this study, the scanning laser ophthalmoscope (SLO) was used, combined with fluorescein angiography, to measure retinal blood flow indices in HIV seropositive patients. METHODS: Arteriovenous passage time (AVP) and perifoveal capillary blood flow velocity (CFV) were measured in 23 HIV infected patients and 23 control subjects with SLO fluorescein angiography. RESULTS: No significant difference in AVP was found between the two groups. However, CFV was significantly reduced in HIV infected patients (p = 0.013). CONCLUSION: Patients infected with HIV show abnormal haemodynamics at the level of the perifoveal capillaries.

Adult↗
PubMed1995

Patterns of diabetic eye care by primary care physicians in the state of Indiana.

Diabetic retinopathy is the leading cause of new blindness in the 20 to 74-age group in the United States. The American Academy of Ophthalmology (AAO) and American Diabetes Association (ADA) have recommended guidelines for eye examination to assist primary care physicians in managing these patients. The purpose of this study is to investigate the patterns of diabetic eye care offered by primary care physicians in the State of Indiana. A survey questionnaire was sent to 1279 primary care physicians in central Indiana. Of those surveyed, 259 (20%) responded. Thirty-five percent of respondents stated that they never refer patients for ocular examination while 26% refer all patients. The remainder refer on a case-by-case basis. Patients who are not referred have their fundus examined only 70% of the time by the primary care physician and 96% of these examinations are performed with an undilated pupil. When referred, 20% of Type I patients are referred at the time of diagnosis and 50% by one year. Of the Type II patients, only 2% are referred at the time of diagnosis and 70% by one year. Ophthalmologists receive 75% of the referrals while optometrists receive 20%. Our results show that a significant number of primary care physicians in the State of Indiana do not follow the recommended guidelines set forth for diabetic eye care.

Adult↗
PubMed1994

Argon laser treatment of trichiasis: a clinical and histopathologic evaluation.

Trichiasis is a common condition of multiple etiologies. Cryosurgery has been advocated as an effective means of treatment but may be associated with serious complications, including scar, skin depigmentation, and lid notching. We treated eight consecutive eyelids with the argon laser. At the end of a 3-month follow-up period, no recurrence was noted. The only observed complication was mild eyelid notching in one eyelid. Histopathologic evaluation of two specimens obtained 10 days and 5 weeks after laser treatment confirmed the highly localized coagulative effect of the laser with minimum destruction of adjacent tissues. Orientation of the eyelid so that the laser beam and the lash follicle are coaxial and careful measurement of the depth of vaporization of the lash follicle are important in confirming complete treatment and minimizing recurrence.

Adult↗
PubMed1994

Efficacy of lateral canthotomy and cantholysis in orbital hemorrhage.

Emergent orbital decompression in tense orbital hemorrhage with compromised ophthalmic blood flow may be achieved with lateral canthotomy, defined as incision of the lateral canthal tendon, and cantholysis, defined as canthotomy combined with disinsertion of at least the inferior crus of the lateral canthal tendon. This study was performed to determine which procedure, canthotomy, canthal tendon disinsertion, or cantholysis, produced the largest reduction in intraocular pressure after simulated orbital hemorrhage in 10 closed ruminant orbits with retrobulbar injections of normal saline. Intraocular pressure (IOP) reductions were measured after canthotomy in five orbits, after lateral canthal tendon disinsertion in five orbits, and after completion of cantholysis in all 10 orbits. Canthotomy produced a mean IOP reduction of 14.2 mm Hg. Canthal tendon disinsertion (CTD) produced a mean IOP reduction of 19.2 mm Hg. Cantholysis produced a mean IOP reduction of 30.4 mm Hg, a significantly (p < 0.05) greater reduction in IOP than that produced by canthotomy or canthal tendon disinsertion alone. Cantholysis in acute orbital hemorrhage may produce significantly greater reduction in IOP, and thus in intraorbital pressure, and allow better perfusion of orbital tissues than either lateral canthotomy or CTD.

Animals↗
PubMed1992

Spontaneous orbital subperiosteal hematomas in patients with liver disease.

Spontaneous orbital subperiosteal hematomas are rare entities. They are often associated with systemic coagulopathies. We present two cases of spontaneous orbital subperiosteal hematomas in patients with systemic coagulopathies resulting from liver disease. One patient was diagnosed with hepatitis B and had spontaneous resolution of the hematoma. Another patient had alcoholic cirrhosis and required an orbitotomy for drainage of a hematoma for compressive optic neuropathy. With the rising incidence of hepatitis B and the prevalence of alcoholic liver disease, it is important to include liver disease in the systemic evaluation of patients with spontaneous orbital subperiosteal hematomas.

Adult↗
PubMed1991

Antibiotic responsive exophthalmos and lateral rectus paralysis.

Sinusitis is an unusual cause of exophthalmos in adults since the advent of antibiotics. Many periorbital complications of sinusitis have been described; however exophthalmos associated with apparent sixth cranial nerve palsy in the absence of ipsilateral sphenoidal sinusitis is a rare and, to our knowledge, unreported complication of sinusitis. We report such a case that was treated with oral antibiotics. We believe that sinusitis must always be considered in adults as a treatable cause of exophthalmos and various orbital complications from isolated lateral rectus paralysis to acute-onset, acquired Brown's syndrome.

Abducens Nerve↗
PubMed1984

Cells that mediate NK like cytotoxicity are present in the human delayed type hypersensitivity response.

By inducing delayed type hypersensitivity (DTH) responses under previously formed skin blisters we determined that cells which mediate natural killer (NK) like cytotoxicity are present in the DTH response in man. Similar levels of killing were not present in cells obtained from skin blisters not associated with positive DTH responses. The DTH response associated killer cell was found to be a mononuclear cell that had presumably undergone stimulation since it not only killed NK sensitive K-562 cells, but also NK resistant Daudi target cells.

Adult↗
PubMed1983

Reduced threshold to suction-induced blister formation in insulin-dependent diabetics.

Diabetics may have an increased susceptibility to cutaneous blister formation clinically manifest as the bullous eruption of diabetes. We evaluated the mechanical force necessary to induce suction blisters in fifteen insulin-dependent diabetics and twenty age-matched normal controls. The mean suction blister threshold for the diabetics was 31.9 minutes versus 68.0 minutes for the controls, a highly significant difference (p less than 0.01). Histologic appearance of suction blisters was similar in diabetic and normal skin, under both light and electron microscopic examination, with a noninflammatory subepidermal separation in the lamina lucida between the cell membrane and the basal lamina. These results demonstrate that insulin-dependent diabetics have a marked reduction in suction blister threshold as compared to age-matched controls.

Adult↗
PubMed1983

Heparin-induced cutaneous necrosis unrelated to injection sites. A sign of potentially lethal complications.

Skin necrosis is a rare complication of heparin administration that is usually localized to injection sites. A 32-year-old insulin-dependent diabetic patient, receiving intravenous (IV) and low-dose heparin sodium therapy, had cutaneous necrosis in areas distant to the sites of injection. Prior to the onset of cutaneous lesions, thrombocytopenia develop]ed in the patient that may have been heparin induced. Heparin may induce the production of platelet aggregating immunoglobulins that predispose persons who are sensitive to the drug to thrombocytopenia, skin necrosis, and thrombotic events. Obesity, diabetes, and treatment with broad-spectrum antibiotics seem to increase the risk of such complications. Cutaneous necrosis secondary to heparin administration may serve as a warning of the potentially lethal complications of IV use. In patients in whom skin necrosis or thrombocytopenia develops, heparin therapy should be discontinued and anticoagulation with an oral agent should be considered.

Adult↗
PubMed1982

D-Penicillamine--induced pemphigus syndrome.

D-Penicillamine is a chelating agent which is effective in the treatment of Wilson's disease, cystinuria, and lead poisoning. In recent years, it has also been used to treat patients with rheumatoid arthritis with good results. The adverse effects of D-penicillamine are many. These include loss of taste, nephrotic syndrome, lupus erythematosus--like syndrome, polymyositis, dermatomyositis, myasthenia gravis, and agranulocytosis. Beginning in 1969, D-penicillamine was reported to induce a pemphigus eruption. We present a patient with D-penicillamine--induced pemphigus erythematosus and review previously reported cases.

Aged↗
PubMed1982

Familial severe twenty-nail dystrophy.

Severe nail dystrophy is a recently described acquired nail disorder. The nails are variably involved and may show thinning, thickening, pitting, ridging, koilonychia, opalescence, and loss of luster. Not uncommonly, some nails are completely spared. Although most of the cases reported were among children, and nail changes showed gradual resolution, in a few cases the disorder is seen in adulthood. We recently investigated a pedigree extending through five generations in which twenty-one of the thirty-seven members were variably afflicted with the dystrophic nail changes. To our knowledge, the familial pattern, inherited as an autosomal dominant trait, has never been previously reported. We propose the term "familial severe twenty-nail dystrophy" for the disorder in this family.

Adult↗
PubMed1982

Coexisting childhood pemphigus foliaceus and Graves' disease.

We report herein the concurrent appearance of childhood pemphigus foliaceus and Graves' disease in a 14-year-old girl who was initially seen with crusted and hyperpigmented plaques on her chest, back, abdomen, and legs. The diagnosis of pemphigus foliaceus was confirmed by biopsy and immunofluorescent microscopic studies while the diagnosis of Graves' disease was based on clinical and laboratory findings. The coexistence of these two immune-mediated diseases in a single patient suggest that some persons may bear a unique predisposition to the development of two or more autoimmune-type disorders that may affect diverse organ systems.

Adolescent↗
PubMed1981

Disseminated Trichosporon beigelii (cutaneum).

Two cases of invasive Trichosporon beigelii (syn. cutaneum) infection are reported and are compared with the eight other previous reports. All affected patients were either immunosuppressed or had recently undergone a surgical procedure. The diagnosis had been delayed and the prognosis was poor. Only two patients recovered after vigorous antimycotic therapy and concomitant remission of their leukemia. A biopsy of the skin lesion, as illustrated in one of our patients, may prove to be useful in the early diagnosis.

Aged↗