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J D Nelson

Publications and source records attributed to J D Nelson.

At least 19 recordsLinked to original sources
PubMed1999

Pancreatic lipase-related protein 1 mRNA in female mouse lacrimal gland.

PURPOSE: Differential display analysis was used to look for gender differences in lacrimal gland gene expression. The expression of a female-specific mouse lacrimal gland mRNA that encoded pancreatic lipase-related protein 1 (PLRP1) was identified and characterized. METHODS: Differential display analysis of the exorbital lacrimal glands of male and female Swiss Webster mice detected a potential female-specific cDNA, designated Y2. Using the technique of rapid amplification of cDNA ends, a full-length cDNA of Y2 was obtained and the nucleotide sequence determined. To assess tissue-specific expression, a labeled Y2 cDNA probe was hybridized to RNA blots of male and female mouse lacrimal, harderian, parotid, mandibular, sublingual, and pancreas glands and liver. Y2 cDNA was also hybridized to RNA blots of male and female rat lacrimal gland and male rat pancreas. To determine subcellular localization, Y2 sense and antisense RNA probes were hybridized to female mouse lacrimal gland frozen sections. RESULTS: GenBank database sequence comparisons indicated that Y2 encoded mouse PLRP1. RNA blots documented that PLRP1 was expressed in female, but not in male, mouse lacrimal gland. PLRP1 mRNA was also expressed in male and female mouse sublingual gland and pancreas. Expression of PLRP1 was not detected in male or female rat lacrimal gland. In situ hybridization showed that PLRP1 was expressed in the acinar cells of the female mouse lacrimal gland. CONCLUSIONS: Lacrimal gland expression of PLRP1 mRNA was gender and species specific. Female, but not male, mouse lacrimal gland expressed PLRPI mRNA. Neither female nor male rat lacrimal gland expressed PLRP1 mRNA. PLRP1 protein may be secreted in mouse tears, where it may function as a lipolytic enzyme, modifying tear film lipids.

Amino Acid Sequence↗
PubMed1998

Sensitivity and specificity of a screening questionnaire for dry eye.

We developed a Dry Eye Screening Questionnaire for the Dry Eye Epidemiology Projects (DEEP), a proposed large epidemiologic study. All persons who screen positive and a small sample of those who screen negative are to be invited for a diagnostic examination. Containing 19 questions, of which only 14 were used in the analysis, the questionnaire takes only a few minutes to administer on the telephone. To construct a discriminator function and thus a ROC curve, we used stepwise multiple regression on screening responses from a clinic series of 77 cases and 79 controls. Stepwise regression may incorporate into the predictor equation variables whose relation to the predicted is only accidental. Further, misclassification rates are underestimated by the resubstitution method, in which the proportion misclassified is obtained from the same dataset in which the discriminator function was fitted. To counter these problems, we randomly divided the data in half. We chose as predictors only those variables (Dry and Irritated) selected by stepwise regression in both data halves. We estimated unbiased misclassification rates using the unbiased test set method, in which the discriminator is fitted in one data half, and misclassification rates are calculated in the other half. Comparison of ROC curves arising from resubstitution and test set estimates indicates that resubstitution bias in misclassification rate estimation is negligible in our data. A resubstitution estimate made on the entire data is thus preferred. The resulting sensitivity/specificity values are reasonably high (e.g., 60%/94%), suggesting that the questionnaire will be a useful screening tool in the DEEP study. A second discriminator using the sum of all 14 responses is similar in its misclassification characteristics to the first discriminator. A second potentially significant error, arising from applying results from a clinical series to a general population, will be investigated as survey results in DEEP become available.

Adult↗
PubMed1997

Dry eye.

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Botulinum Toxins, Type A↗
PubMed1996

Comparison of methods of assessing vitamin A status in children.

OBJECTIVE: A study of children (2-8 years; n = 613) in Belize, Central America, was conducted to determine what proportion of the children might be at risk of vitamin A (vit A) deficiency. The data provide an opportunity to compare results of three methods of assessing vit A status in a population which was not severely malnourished. Serum retinyl ester concentrations were also determined; their relevance to one of the tests, the relative dose response (RDR) test, is discussed. METHODS: The three methods of assessing vit A status were: RDR test, fasting serum retinol concentration, and conjunctival impression cytology (CIC). Retinol-binding protein (RBP), serum retinyl esters and serum zinc concentrations were also determined. RESULTS: Inadequate vit A status was indicated for 17% of subjects by the RDR test (14% cutoff), for 24% by fasting serum retinol concentration (< 0.87 mumol/L), and for 49% by "abnormal" CIC score. Retinyl esters constituted 24% of serum retinoids at the time (5 hours after a retinyl palmitate dose) at which the second blood sample is taken for the RDR test. Regression tree analyses (CART) indicated ethnicity was a predictor of RDR score; ethnicity, stunting and age were predictors of fasting serum retinol concentration; ethnicity and stunting were predictors of 0-hour retinyl ester concentration. CONCLUSION: The three indices of vit A status did not identify the same individuals nor indicate the same percentage of the population to be at risk for vit A deficiency. Increased concentrations of retinyl esters at 5 hours compared to those at 0 hours suggest that insufficient retinol may have been taken up by the liver at 5 hours to release all accumulated retinol-binding protein (RBP) in deficient individuals; prevalence of vit A deficiency might therefore be underestimated by the RDR test. The selection of ethnicity as a predictor of RDR score and of 0-hour retinol and retinyl ester concentrations suggests that factors other than vit A status affect vit A metabolism and may affect the RDR test.

Belize↗
PubMed1995

Simultaneous evaluation of tear turnover and corneal epithelial permeability by fluorophotometry in normal subjects and patients with keratoconjunctivitis sicca (KCS).

PURPOSE: To simultaneously determine the tear turn over rate (TT) and corneal epithelial permeability (Pdc) in normal subjects and patients with KCS by a single-drop fluorophotometric technique using disodium fluorescein (DSF) or carboxyfluorescein (CF). METHODS: DSF was instilled in one eye chosen at random and CF in the fellow eye of 13 normal subjects and in 13 patients with KCS. TT and Pdc were determined using a single-drop technique on a Fluorotron Master. RESULTS: In normals and KCS subjects, TT was found to be independent of age and sex and essentially identical for DSF and CF. TT was approximately 42% lower in KCS subjects than normals (Table). TT was independent of Schirmer's I and Pdc. [table: see text] Pdc values were similar for DSF and CF in normals and increased with age. In KCS subjects, Pdc was 3-4 times higher compared to normal subjects (p < 0.01) and was directly correlated with the severity of corneal punctate staining. Pdc was independent of TT. CONCLUSION: Patients with KCS are more susceptible to the therapeutic and toxic effects of topical medications and preservatives due to increased corneal epithelial permeability. With the decreased TT in KCS patients, there is also slower elimination of substances from the tear film. This, combined with the increase in epithelial permeability, puts the KCS eye doubly at risk for the toxic effects of topically applied substances.

Adult↗
PubMed1994

In vitro evaluation of the effects of metronidazole on rabbit corneal epithelial cells.

Because of its usefulness in treating facial rosacea, metronidazole may also be an effective treatment for ocular rosacea. The toxicity of metronidazole on the corneal epithelium has not previously been reported. In this study, the effects of metronidazole on rabbit corneal epithelium in vitro were evaluated. Epithelial cell cultures were exposed to various concentrations of metronidazole to determine its effect on cell morphology, viability, and wound healing. Both morphological changes and cell loss were seen after 1 day of incubation in media containing metronidazole at concentrations of > or = 3.0 mg/ml. In media with metronidazole at 1.0 mg/ml, these toxic effects were not seen. The effects of metronidazole on wound healing were determined by comparing the area of wounds in the epithelial cell layer for time periods of up to 44 h. There was no statistically significant delay in wound closure when cells were incubated in media containing metronidazole at a concentration of 2.0 mg/ml as compared with cultures incubated in media without metronidazole. However, a significant delay in wound closure occurred at concentrations of > or = 3.0 mg/ml. The results at these drug concentrations suggest that metronidazole has low corneal epithelial toxicity. Allowing for the dilutional effects of tears in patients with normal tear function, concentrations of 4.0-5.0 mg/ml (0.4-0.5%) would probably be tolerated by the corneal epithelium. Clinical safety and efficacy studies are necessary to determine if topical metronidazole will prove useful for the treatment of ocular rosacea.

Animals↗