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Biomedical subjects

H H Brown

Publications and source records attributed to H H Brown.

At least 37 records · Page 2Linked to original sources
PubMed1988

Quantitation of tumor seeding from fine needle aspiration of ocular melanomas.

Twenty-two fine needle (30 gauge) aspirations were performed in eyes enucleated for the clinical diagnosis of melanoma. Cytologic preparations were evaluated for adequacy of material, and needle tracts were evaluated for tumor implantation. A scleral marking method was used to identify all needle tracts. The number of tumor cells in tracts of direct transscleral aspirates was compared to those in tracts of indirect aspirates that traversed the anterior chamber or vitreous. Cellular material obtained with 30-gauge needles was sufficient for the diagnosis of malignant melanoma in all but one case. While 14 of 21 (67%) of all fine needle aspiration tracts and eight of 15 (53%) of indirect tracts contained tumor cells, the number of tumor cells was less than that associated with tumor growth in experimental models. Indirect aspirate tracts contained significantly fewer cells than tracts of direct aspirates (P less than .001).

Biopsy, Needle↗
PubMed1987

Miliary retinitis in coccidioidomycosis.

We studied the pathologic features of a rare case of coccidioidomycosis retinitis in a 12-year-old girl. At autopsy there were multiple small lesions throughout the vital organs. Ocular lesions were restricted to the posterior part of the fundus. Step-level serial sectioning including the optic axes of both eyes showed 29 discrete retinal and 22 choroidal granulomas. Topographic analysis demonstrated random distribution of lesions throughout the fundus. Retinal granulomas were centered within layers served by the retinal circulation. Choroidal lesions most often involved the middle vascular layer and in only two areas focally disrupted Bruch's membrane. The pigment epithelium was intact. Retinal granulomas were not topographically associated with choroidal lesions.

Child↗
PubMed1987

Ocular pathologic findings in neonatal adrenoleukodystrophy.

Ocular pathology in a case of neonatal adrenoleukodystrophy (ALD) showed marked degeneration of photoreceptor cells throughout the retina including the macula. Macroscopically visible white opacities in the cortical vitreous of the posterior fundus were shown immunohistochemically and ultrastructurally to be macrophages containing bileaflet inclusions, a finding previously unreported. Additional findings included extensive loss of the retinal nerve fiber and ganglion cell layers, optic nerve degeneration, and bileaflet inclusions in retinal pigment epithelial cells and macrophages of the retina and optic nerve. Focal retinal pigmentary changes were observed that histologically were different from retinitis pigmentosa.

Adrenoleukodystrophy↗
PubMed1981

Liquid-chromatographic assay for urinary homovanillic acid, with fluorescent detection.

We describe a procedure for measuring urinary homovanillic acid by "high-performance" liquid chromatography. The pH of urine samples is adjusted, and they are chromatographed directly on an octyl silica column. The effluent is reacted with a ferricyanide reagent, to convert homovanillic acid to a product that is fluorescent at 420 nm on excitation at 320 nm. The standard curve is linear up to a homovanillic acid concentration of 20 mg/L; the detection limit is 0.3 mg/L. The method is evaluated for precision, recovery, potential interference, and reference values, and compared (r = 0.99) with a published spectrophotometric method. The proposed method is suitable for the routine analysis for homovanillic acid in urine.

Chromatography, High Pressure Liquid↗
PubMed1979

Liquid-chromatographic assay for urinary 3-methoxy-4-hydroxymandelic acid, with use of a periodate oxidative monitor.

We describe a "high-performance" liquid-chromatographic procedure for measuring 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid) in urine. The compound is quantitatively extracted from urine by use of an automated system, including an anion-exchange resin. After elution from the resin and concentration by air drying, the urine extract is chromatographed on an octyl silica column, with use of a buffered mobile phase. To overcome interference from other organic acid in the extract, the column effluent is reacted with periodate in an analytical system to oxidize the analyte and internal standard to products that absorb at 360 nm. We evaluated the procedure for precision, linearity, analytical recovery, interfering substances, and correlation with an established procedure. The combination of a preliminary resin extraction, a liquid-chromatographic separation, and a periodate oxidative monitor results in a rapid, specific method that can be adapted for use in the clinical laboratory.

Autoanalysis↗
PubMed1979

Fluorometric measurement of theophylline.

We have developed a simple, sensitive procedure in which theophylline in a solution of cerium(IV) acts as an oxidizable compound to produce fluorescent cerium(III) when combined with a microsolvent for extraction at pH 7.9. This method provides excellent sensitivity and specificity because other xanthines and phenobarbital, secobarbital, amobarbital, and phenytoin do not interfere. Day-to-day reproducibility (coefficient of variation, 6%) is attained for theophylline concentrations of 10 and 20 mg/L. Results correlate well with liquid chromatography and enzyme immunoassay procedures. Total analysis time for a single sample is 10 min.

Cerium↗
PubMed1979

Localization and activities of lysosomal enzymes in jejunal and ileal epithelial cells of the young pig.

The localization and the specific activities of lysosomal enzymes in jejunal and ileal epithelium of suckling pigs were determined. Acid phosphatase was found in pinocytotic vesicles and vacoles at both intestinal sites in pigs examined during (less than or equal to 1 day old) or shortly after (2 days old) closure. These pinocytolically active vesicles and vacuoles were determined to be phagolysosomes. In the ileum, phagolysosomes persisted well after closure, at an age (10 days) when ileal epithelium retains the capacity for pinocytotic uptake of immunoglobulin, but does not transport it to blood. Neither jejunum nor ileum contained phagolysosomes at an age (30 days) when the intestine had lost both uptake and transport capacities. The specific activities of acid phosphatase and cathepsin B-1 in jejunum were similar for all age groups. However, the activities of these enzymes in ileum of 10-day-old pigs were three and five times greater than at any other age or site. The results are consistent with phagolysosomes in the ileum of 10-day-old pigs functioning as a "barrier" which prevents transport of the macromolecules which are taken up pinocytotically by this epithelium. The results do not permit conclusions whether (or not) the phagolysosomes which appear in jejunum and ileum of pigs less than or equal to 1 day old contribute to closure, because the transcellular route for immunoglobulin absorption in pigs has not been precisely defined.

Acid Phosphatase↗
PubMed1977

Simple procedure for measuring total protein in urine.

We describe a procedure for measuring total protein in urine. The method is simple, sensitive, and free of interference from drugs that are known to affect other commonly used methods. The CV for a 1.1 g/liter urine control in daily, routine use is 4.6%. The procedure involves adsorbing the protein onto cellulose powder, binding of Ponceau S dye by the protein, washing away excess dye, and eluting the bound dye into dilute NaOH for colorimetry. Comparison of results by this method with those by the biuret and turbidimetric procedures showed good agreement in those cases where the specimens were suitable for assay by the comparison methods.

Biuret Reaction↗