Phenotypic characterization of epiphycan-deficient and epiphycan/biglycan double-deficient mice.

OBJECTIVE: To characterize the in vivo role epiphycan (Epn) has in cartilage development and/or maintenance. METHODS: Epn-deficient mice were generated by disrupting the Epn gene in mouse embryonic stem cells. Epn/biglycan (Bgn) double-deficient mice were produced by crossing Epn-deficient mice with Bgn-deficient mice. Whole knee joint histological sections were stained using van Gieson or Fast green/Safranin-O to analyze collagen or proteoglycan content, respectively. Microarray analysis was performed to detect gene expression changes within knee joints. RESULTS: Epn-deficient and Epn/Bgn double-deficient mice appeared normal at birth. No significant difference in body weight or femur length was detected in any animal at 1 month of age. However, 9-month Epn/Bgn double-deficient mice were significantly lighter and had shorter femurs than wild type mice, regardless of gender. Male Epn-deficient mice also had significantly shorter femurs than wild type mice at 9 months. Most of the deficient animals developed osteoarthritis (OA) with age; the onset of OA was observed earliest in Epn/Bgn double-deficient mice. Message RNA isolated from Epn/Bgn double-deficient knee joints displayed increased matrix protein expression compared with wild type mice, including other small leucine-rich proteoglycan (SLRP) members such as asporin, fibromodulin and lumican. CONCLUSION: Similar to other previously studied SLRPs, EPN plays an important role in maintaining joint integrity. However, the severity of the OA phenotype in the Epn/Bgn double-deficient mouse suggests a synergy between these two proteins. These data are the first to show a genetic interaction involving class I and class III SLRPs in vivo.

Interpersonal identity formation during early adolescence.

The purpose of this study was to explore interpersonal identity development during early adolescence. Sixth, seventh, and eighth graders (N = 356) were administered the interpersonal identity scale of the Revised Extended Objective Measure of Ego Identity Status (Bennion & Adams, 1986). Findings revealed that 55% of the sample fell into one of the four discrete identity status categories, with 62% of this group classified as either diffused or foreclosed. Within these two less sophisticated statuses, grade and gender differences were observed. The interpersonal domains of friendship, dating, and sex roles were salient for the young adolescents in this sample, particularly for those classified as diffused and foreclosed. Findings reflect the emergent and/or transitional nature of interpersonal identity development during early adolescence.

Measurement of oxygen production by in vitro human and animal lenses with an oxygen electrode.

PURPOSE: This paper describes an advantageous method of measuring the activity of the enzyme catalase, which has an important antioxidative role in the lens. This method allows the measurement of catalase in whole lenses. METHODS: Exposure to UVA (99% UV-A) radiation was used to stress animal and human (Eye Bank) lenses in vitro. The ability of lens catalase to convert H2O2 into O2 was measured directly, using an oxygen electrode and meter. This method is very specific, as catalase is the only enzyme that converts H2O2 to O2. RESULTS: Catalase in the lenses of humans, rabbits, and squirrels catalyzed the production of O2 from H2O2 very efficiently. The anterior equatorial regions of these lenses were the most active O2 producing areas. More than 95% of lens catalase activity was found in the capsule-epithelium layer. Exposure to UVA radiation, up to approximately 100 J/cm2 in 18 h, strongly inhibited O2 production from 0.77 mM H2O2 by the lenses. Catalase activity decreased with increasing age. Mixed cataractous human lenses produced O2 from H2O2 at only 60% of the rate of normal lenses of similar ages. Nuclear cataracts produced O2 at only 75% of the rate of normal lenses. Alpha-tocopherol (10(-5) M) protected lens catalase activity strongly. Alpha-tocopherol is known to accumulate in and protect against cell membrane peroxidation, and against singlet oxygen formation. These oxidative mechanisms appear to contribute to catalase photoinactivation. CONCLUSIONS: The method described indicated that catalase is a crucial antioxidative enzyme in the normal lens. Its inactivation could upset the oxidation-reduction balance in the lens and stimulate lens opacification.

Structural and functional changes in catalase induced by near-UV radiation.

Part one of this study shows that exposure of purified beef liver catalase in buffered solutions to BL lamps that provide a mixture of 99% UVA and 1% UVB (to be labeled UVA) alters its chemistry and enzymatic activity. Thus, its spectral absorbance lost detail, it aggregated and exhibited a lower isoelectric point and its enzymatic activity was substantially reduced. These photochemically induced changes were increased by irradiation in phosphate buffer or in physiological medium (minimal essential medium) containing riboflavin and tryptophan. Neither alpha-tocopherol nor deferoxamine were protective against these UVA-induced changes in pure catalase. We further investigated the effect of UVA radiation on the activity of catalase in cultured lens epithelial cells and the protective effects of antioxidants. Cultured lens epithelial cells of rabbits and squirrels were exposed to near-UV radiation with representation in the UVA region of 99% and 1% UVB. Catalase assays were done on homogenate supernatants of cells kept dark or UV exposed. In some instances, cells were cultured in medium containing alpha-tocopherol or deferoxamine prior to UV radiation. Comparisons were made between UV-exposed lens cell catalase activity when exposure was done with or without the antioxidants. The UVA radiation was strongly inhibitory to both rabbit and squirrel lens epithelial cell catalase activities. The range of fluxes of near UV radiation was compatible with that which could reach the lens from the sunlit environment. Catalase inactivation was lessened in cells preincubated with alpha-tocopherol and deferoxamine. This suggests that both singlet oxygen and hydroxyl radical formation may be involved in near-UV damage to lens epithelial cell catalase. Such inhibition of catalase by near-UV would enhance H2O2 toxicity and stimulate SH oxidation so as to damage the lens.

Damage to cultured lens epithelial cells of squirrels and rabbits by UV-A (99.9%) plus UV-B (0.1%) radiation and alpha tocopherol protection.

The purpose of this research is to observe the near-UV radiation induced damage to cultured rabbit and squirrel lens epithelial cells as related to destruction and alterations of specific biochemical targets in the cells and to determine protective effects on the cells and targets that are provided by alpha-tocopherol. Confluent monolayers of cultured rabbit and squirrel lens epithelial cells were exposed to black light (BL) lamps, which emit predominantly UV-A radiation. These cells received a mixture 3 J/cm2 of UV-A and 4 mJ/cm2 of UV-B per h. This mixture is termed near UVA (i.e.: predominantly UV-A). Cells were exposed in Tyrode's or in MEM without or with alpha-tocopherol added at 2.5-10 micrograms/ml. Analyses of cell viability and survival, the physical state of cytoskeletal actin, and the activities of Na-K-ATPase and catalase were made. Exposure to near UVA damaged these cells as measured by vital staining and colony forming ability. Pretreatment with alpha-tocopherol decreased the magnitude of near UVA cytotoxicity. Near UVA exposure in MEM always produced more damage to the cells and biochemical targets than in Tyrode's. Cytoskeletal actin was degraded and the activities of Na-K-ATPase and catalase were markedly inhibited by UV-exposure. All of these targets were at least partially protected by alpha-tocopherol in the medium. Without alpha-tocopherol added to the media, the viability and survival of the cells did not recover even after 25 h of incubation. Cell viability was better protected from near UVA by alpha-tocopherol than was the ability to grow into colonies. This indicates that alpha-tocopherol protects actin, catalase, and Na-K-ATPase from near UVA damage.

Classification and protein distribution in a series of intracapsular cataracts.

The crystallin profiles of the cortices and nuclei of intracapsular cataractous lenses were studied by high pressure liquid chromatography (HPLC), polyacrylamide gel electrophoresis (PAGE), and dot blotting. The complete personal and medical history of 381 patients and the Cooperative Cataract Research Group (CCRG) classification of each were obtained. Few statistically significant associations between patient personal history and cataract types were found. Protein profiles of selected cataracts which had specifically located opacities (i.e., nuclear only, cortical only, etc.) were studied in detail. Sodium dodecyl sulphate-PAGE revealed few differences in lens-soluble proteins between cataractous and normal cortices or nuclei. By HPLC, the proteins of cataractous cortices and their nuclei differed very little from age-matched controls. The cortical proteins of nuclear cataracts appeared normal. However, two major alterations of proteins were observed in the nuclei of dense nuclear cataracts. Increased high molecular weight protein and increased components with molecular weights < 20,000 Da were found in cataractous nuclei as compared with normal age-matched control lens nuclei. Dot blot (immunological) analyses identified the crystallins of normal lenses that eluted from the HPLC column more efficiently than those of cataractous lenses. Cortical protein HPLC samples had the most specificity. Nuclear protein HPLC samples of older normal and cataractous lenses had little if any alpha crystallin specificity in the void volume peak. A relation between the presence of opacities and changes in molecular weight distribution of crystallins was found in the opaque nuclei but not in the opaque cortices.(ABSTRACT TRUNCATED AT 250 WORDS)

Family life education needs of mentally disabled adolescents.

This study identifies the family life education needs of minimally and mildly mentally disabled adolescents as a basis for curriculum development. Respondents were 134 students from 11 school districts in a midwestern state. Through the administration of 50 needs statements, they were asked to indicate the magnitude of need and the extent to which the need was being met. Special education teachers were allowed to assist in reading or interpreting the directions and needs statements. Priority need statements--those with a high need score which were not being met--are related to the decision to parent, careers and work, marriage and parenthood, decision making and goal setting, and resource management. Six clusters or groups of family life education needs were identified: Basic Nutrition, Teenage Pregnancy, Sex Education, Developmental Tasks of Adolescents, Marriage and Parenthood, and Planning and Decision Making. Females reported significantly greater need for information on nutrition, teenage pregnancy, and marriage and parenthood.

Sexuality education instructional techniques: teacher usage and student preference.

This paper identifies instructional techniques utilized by 89 secondary school teachers and those preferred by 334 secondary school students when 20 sexuality education topics are taught in the classroom. Instructional techniques most often utilized by teachers and preferred by students include large group discussion, educational media, guest speakers, case study, lecture, small group work, and role play. The findings indicate that large group discussion was most often employed by teachers and preferred by students when teaching social and emotional aspects of sexuality such as self-awareness, feelings and emotions, building relationships, and communicating with others. Educational media and guest speakers were the instructional techniques used and preferred to address some of the physiological aspects of sexuality such as reproductive systems, conception, childbirth, and birth control. Significant differences using the chi-square test of independence were found between teacher and student responses for 16 of the 20 topics.