Differential regulation of membrane-associated mucins in the human ocular surface epithelium

PURPOSE: Membrane-associated mucins present in the apical cells of the ocular surface epithelium (MUC1, -4, and -16) are believed to contribute to the maintenance of a hydrated and wet-surfaced epithelial phenotype. Serum and retinoic acid (RA) have been used to treat drying ocular surface diseases. The goal of this study was to determine whether serum or RA regulates the production of membrane-associated mucins in human conjunctival epithelial cells. METHODS: A telomerase-immortalized human conjunctival epithelial cell line (HCjE) was used. Cells were cultured in serum-free medium to confluence and then cultured with either 10% calf serum or with 100 nM RA for 0 to 72 hours. Conventional RT-PCR was used to determine the expression of retinoic acid receptors (RARs) and quantitative real-time PCR was used to investigate the mRNA expression of MUC1, -4, and -16. Protein levels were assayed by immunoblot analysis, using the antibodies HMFG-2, 1G8, or OC125, which are specific to MUC1, -4 and -16, respectively. To determine whether RA-associated MUC4 mRNA induction is a direct or indirect effect, HCjE cells were treated with RA and the protein synthesis inhibitor cycloheximide (1.0 microg/mL) for 12 hours. RESULTS: MUC1 and -16, but not -4, mRNAs were detectable in HCjE cells grown in serum-free medium. Real-time PCR revealed that MUC4 mRNA was significantly induced by serum 3 hours after its addition, and that MUC1 and MUC16 mRNA levels were significantly upregulated at 72 hours. Western blot analysis demonstrated that the MUC1, -4, and -16 proteins increased over time after addition of serum. Conventional RT-PCR analysis demonstrated that RAR-alpha and -gamma mRNA were expressed in native human conjunctival tissue as well as in the HCjE cells. Treatment with RA upregulated the expression of both MUC4 and -16 mRNA and protein, but MUC1 was unaffected. Because the protein synthesis inhibitor cycloheximide did not prevent the RA-associated induction of MUC4 mRNA, the action of RA on the MUC4 promoter may be direct. CONCLUSIONS: The membrane-associated mucins of the ocular surface epithelia, MUC1, -4, and -16, are differentially regulated by serum and RA in the telomerase-immortalized human conjunctival epithelial cell line. Serum derived from vessels in the conjunctiva may play an important role in mucin regulation in the ocular surface epithelia. These data also support the clinical efficacy of autologous serum and RA application in patients with ocular surface diseases. Furthermore, the data suggest that MUC4 and -16 are particularly important hydrophilic molecules involved in maintenance of a healthy ocular surface.     

Measuring risk perception among low-income minority primary care patients

Studying patients' risk perceptions by ascertaining the probabilities of developing a disease is suboptimal, as patients might have difficulty using numerical expressions to depict the probabilities/chances of developing a disease. We surveyed patients at 2 community health centers and assessed risk perception by patients' self-reported chance of developing a disease (expressed in percentages), patients' relative chance of developing a disease compared to others' chance of developing a disease, and patients' ranked chances of developing different diseases. Many patients had difficulties understanding percentages and most patients overestimated their absolute risk. However, most patients indicated that they had a lower chance of developing diseases when compared to others. Patients with known risk factors (smoking) indicated a higher relative risk of developing an associated disease (lung cancer). Patients' ranked chances of developing different diseases were consistent with the actual frequency of developing a disease. Although patients had difficulty expressing risk in percentages, they estimated their risks well through comparisons with others and by ranking of disease frequencies.     

Intraamniotic endotoxin increases lung antioxidant enzyme activity in preterm lambs

Proinflammatory stimulation resulting from intraamniotic endotoxin improves lung function, increases surfactant protein mRNA expression and protein content, increases alveolar and lung saturated phosphatidylcholine pools, and accelerates lung morphometric maturation in fetal sheep. The mechanism for induction of lung maturation does not involve an increase in fetal cortisol. The effect of endotoxin on the maturation of a different lung system, the antioxidant enzyme (AOE) system, has not been examined. Therefore, we hypothesized that intraamniotic endotoxin would produce acceleration of AOE activity in fetal sheep at similar doses and schedule of administration to those producing lung functional and surfactant maturation. In a dose-response study, intraamniotic injections of 1, 4, 20, or 100 mg of Escherichia coli 055:beta5 endotoxin were administered 7 d before preterm delivery of sheep at 125 d gestation. In a study examining time interval of administration before delivery, 20 mg of endotoxin was injected at either 1-, 2-, 4-, 7-, or 15-d intervals before preterm delivery at 125 d. Doses of 1-100 mg of endotoxin produced significant increases in glutathione peroxidase activity; doses of 4-100 mg significantly increased catalase activity, whereas doses of 20-100 mg resulted in significant increases in total superoxide dismutase activity. Glutathione peroxidase activity was elevated within 2 d, whereas superoxide dismutase was increased by 4 d and catalase activity increased by 7 d after endotoxin. No AOE increases were sustained for 15 d. Endotoxin increased fetal lung AOE activity at similar dosing amounts and intervals to those producing maturation of lung function and surfactant. Thus, mechanisms involving proinflammatory stimulation, unrelated to glucocorticoid hormones, can induce maturation of the AOE system of the fetal lung.     

Knowledge and beliefs about influenza,pneumococcal disease,and immunizations among older people

OBJECTIVES: Despite the burden of disease caused by influenza and pneumococcus, immunization rates are moderate and have not reached national goals set for 2010. This study's objective was to identify patient knowledge, attitudes, and beliefs that serve as facilitators of and barriers to influenza and pneumococcal vaccination. DESIGN: A survey conducted in 2000 by computer-assisted telephone interviewing. SETTING: To encounter a broad spectrum of patients and healthcare systems, we sampled patients at inner-city health centers, Department of Veterans Affairs outpatient clinics, and rural and suburban practices. PARTICIPANTS: Inclusion criteria were patients aged 66 and older and an office visit after September 30, 1998. MEASUREMENTS: Responses to questionnaire. RESULTS: Overall, 1,007 (82%) interviews were completed among 1,234 people contacted by phone. Vaccination against pneumococcal disease was significantly related to being able to accurately describe one or more classic symptoms of pneumonia (P =.05). Vaccination against influenza and pneumococcal disease was significantly related to belief that vaccination was the best way to prevent these diseases (P <.001). The unvaccinated reported that they felt they were not likely to contract influenza and that they did not know they needed the pneumococcal vaccine. Access was not related to vaccination status. CONCLUSIONS: Educational campaigns to increase vaccination rates among older adults should focus on symptoms of, risk for, and severity of influenza and pneumococcal diseases and encouraging physicians to recommend the vaccines to their patients.     

Variation in the amount of T antigen and N-acetyllactosamine oligosaccharides in human cervical mucus secretions with the menstrual cycle

It has been hypothesized that the carbohydrate portion of mucins present in the endocervical canal plays an important role in conferring specific physicochemical properties (e.g. viscosity and hydration) to the mucus gel through the menstrual cycle. Our recent finding showing an increase in the amount of MUC5B mucin protein at midcycle has raised the question of whether the mucin O-glycan content also varies to confer specific hydrodynamic properties to secreted mucins during ovulation. Using lectins as carbohydrate probes, we have identified two common mucin oligosaccharide structures, T antigen and N-acetyllactosamine, within secretory granules in human endocervical glands during the proliferative phase of the menstrual cycle. Analysis of endocervical secretions by enzyme-linked lectin assay revealed that the amounts of T antigen and N-acetyllactosamine are maximal at midcycle. Lectin blot assay of immunoprecipitated MUC5B demonstrated that the mucin is a carrier of the T antigen and N-acetyllactosamine oligosaccharides in cervical mucus secretions. The amounts of T antigen and N-acetyllactosamine oligosaccharides on MUC5B increased during the first half of the cycle, peaked at midcycle, and dramatically dropped at the end of the cycle. The peak in MUC5B mucin protein and carbohydrate content coincides with the change in mucus character that occurs at midcycle. The role of O-glycans on mucins may be to hold water within the endocervical canal during ovulation to facilitate sperm migration.     

The cell-layer- and cell-type-specific distribution of GalNAc-transferases in the ocular surface epithelia is altered during keratinization

PURPOSE: It has been hypothesized that the biosynthesis of O-linked glycans on proteins, particularly on the highly O-glycosylated mucins, by the corneal and conjunctival epithelium is necessary for the protection and maintenance of a healthy ocular surface. The initial step in O-glycosylation is the enzymatic addition of N-acetyl galactosamine (GalNAc) to serine and threonine residues by a large family of polypeptide GalNAc-transferases (GalNAc-Ts). The purpose of this study was to determine the cellular distribution of GalNAc-Ts in the normal ocular surface epithelia and to compare their distribution with that in pathologically keratinized conjunctival epithelia. METHODS: Five conjunctival biopsy specimens and 5 corneas from normal individuals, and 14 conjunctival specimens from patients with ocular cicatricial pemphigoid (OCP) were used. Based on the histologic characteristics of their epithelia, OCP specimens were divided into two groups: less advanced, nonkeratinized (n = 6), and late-stage, keratinized (n = 8). Five monoclonal antibodies raised against the GalNAc-T1, -T2, -T3, -T4, and -T6 isoenzymes, were used for immunofluorescence microscopic localization according to standard protocols. RESULTS: Immunohistochemical studies revealed the presence of GalNAc-T2, -T3, and -T4 isoforms within the stratified epithelium of the cornea and the conjunctiva. The GalNAc-T4 isoenzyme was found in the apical cell layers, whereas GalNAc-T2 was found in the supranuclear region of the basal cell layers of both cornea and conjunctiva. GalNAc-T3 was distributed throughout the entire ocular surface epithelium, whereas GalNAc-T1 was found in scattered cells in conjunctiva only. Binding of antibody to GalNAc-T6 was restricted exclusively to conjunctival goblet cells. There were distinct alterations in expression patterns of GalNAc-T2, -T6, and -T1 in nonkeratinized OCP epithelia compared with normal epithelia. Both GalNAc-T2 and -T6 were expressed in the apical stratified epithelia, and T1 was detected in all cell layers in five of six biopsy specimens. By comparison with nonkeratinized OCP epithelia, a marked reduction in the binding of GalNAc-T antibody was observed in the late-stage keratinized conjunctival epithelia of patients with OCP. In all samples, apical GalNAc-T2 was absent, and GalNAc-T6 was entirely absent. Only one of eight samples was positive for GalNAc-T1. CONCLUSIONS: The presence of GalNAc-T isoenzymes in the human corneal and conjunctival epithelia is cell-layer and cell-type specific. The increased distribution of GalNAc-Ts observed in early stages of the keratinization process in patients with OCP suggests a compensatory attempt of the ocular surface epithelium to synthesize mucin-type O-glycans to maintain a wet-surface phenotype. This early increase in isoenzymes in nonkeratinized OCP epithelia is reduced as keratinization proceeds in the disease.     

The Birth Controllers: Limitations on Out-of-Hospital Births

The historical trend away from out-of-hospital births and toward hospital births reflects an effort by physicians to retain control of maternity services. Physicians have sought to discourage nonhospital births by reducing consumer demand and by restricting midwifery and physician attendance at nonhospital births. Various strategies have been used to formally and informally restrict birth options. The impact of legislative and other restrictions on place of birth are discussed.