Lens alpha-neoproteins

The formation of lens alpha-neoprotein molecules which are built by the association of A and B subunit chains of alpha-crystallin but have a different quaternary structure than the native protein is a posttranslational process that progresses through the life span. Alpha-neoproteins occur regularly in all mature mammalian lenses tested. The mechanisms that have been identified for the formation of alpha neoproteins are imbalance in the biosynthesis of A- to B-chains, which leads to a ratio of less than 2A-chains to 1B-chain, and derivation of the chains after their initial association into native alpha-crystallin. In terms of quantity of neoproteins, no significant differences have been found between lenses with developing cataracts and normal control lenses of corresponding age. The possibility that there are structural differences between alpha-neoproteins in normal and cataractous lenses of the same age, as well as potential differences among alpha-neoproteins isolated from normal lenses of different ages, are presently under investigation.     

Mortality studies of machining fluid exposure in the automobile industry III: A case-control study of larynx cancer

A case-control study of larynx cancer was conducted within a cohort of automobile workers exposed to metal working fluids, commonly referred to as machining fluids (MF). Results are based on 108 cases of larynx cancer and 5:1 matched controls. Risks associated with specific types of MF, as well as specific components of the fluids were evaluated. Based on a retrospective exposure assessment, lifetime exposures to straight and soluble fluids, grinding particulate, biocides, selected metals, sulfur, and chlorine were examined. Exposure to asbestos and acid mists at two of the three study sites was also characterized. Results suggest that straight mineral oils are associated with almost a two-fold excess in larynx cancer risk. There was also evidence of an association with elemental sulfur, commonly added to straight MF to improve the integrity of the materials under extreme pressure and heat. It is not clear whether sulfur is causally related to an excess relative risk of larynx cancer or whether the observed association is the result of unmeasured confounding by another contaminant or process feature. For example, the high stress operations that require MF enriched with sulfur are also more likely to produce polycyclic aromatic hydrocarbons (PAHs) during the process. Thus, the observed association with sulfur may be due to an association with PAH. The finding of excess risk of laryngeal cancer associated with MF is consistent with several previous reports in the literature. This is the first study, however, to distinguish straight mineral oils from other types of MF. Based on these findings, a general reduction in concentrations of straight mineral oil particulate in occupational environments would be prudent.     

Cognitive impairment of acute onset in the Consortium to Investigate Vascular Impairment of Cognition (CIVIC) study: occurrence, correlates, and outcomes.

OBJECTIVE: Having demonstrated that dementia of acute onset represents a distinct syndrome with distinct outcomes, the authors investigated whether similar attributes describe cognitive impairment of acute onset (CIAO). METHODS: The authors conducted a secondary analysis of the Consortium to Investigate Vascular Impairment of Cognition study. RESULTS: Ninety patients met our criteria for CIAO. Compared with cognitive impairment of gradual onset, CIAO was associated with vascular features (odds ratio [OR]: 12.3, 95% confidence interval [CI]: 3.2-47.9), dementias other than Alzheimer disease (OR: 6.5, 95% CI: 2.1-20.8), and decreased survival (hazard ratio: 2.8, 95% CI: 1.6-4.6). CONCLUSIONS: Patients with CIAO are clinically identifiable and have distinct outcomes.     

The stromal cell line S17 supports the growth of lipopolysaccharide-stimulated CBA/N spleen cell colonies in vitro.

The expression of an X-linked defect in the CBA/N strain of mice has been found to result in a number of immune abnormalities. These include low responsiveness to antigens and a greatly reduced ability to respond to many of the common B cell mitogens. An in vitro manifestation of this condition is the virtual inability of CBA/N B cells to form colonies in lipopolysaccharide (LPS)-containing semisolid agar cultures. In this report we show evidence that the colony-forming ability of CBA/N spleen cells can be effectively restored by the bone marrow stromal-derived cell line S17. Spleen cells from 4-5-week-old homozygous CBA/N female mice were grown in double-layer agar cultures containing S17 feeder layers. Control cultures contained the fibroblast-like cell line 95.17 or were treated with medium alone. It was found that at an input cell concentration of 10(4) cells per plate, CBA/N colony formation was increased from a frequency of approximately 1 in 5,000 to 1 in 50 total splenic cells. Studies with purified surface immunoglobulin-positive cells indicate the direct involvement of S17 in this process. The CBA/N colonies formed were dependent on the presence of a mitogen (LPS) and secreted detectable amounts of IgM. Major implications of these findings and the application of this assay system to study the CBA/N defect have been discussed.     

CURRENT CONCEPTS IN INFANT NUTRITION

Nutritional needs vary during the first year of life according to the infant's individualized pattern of growth and amount of physical activity. After delivery, the infant must make many physiologic adjustments, develop immunologic defenses, and take in adequate nutrients for survival. The type and consistency of foods change as the gastrointestinal system matures and becomes able to metabolize the components and excrete the needed metabolites of increasingly complex foods. The recommended dietary allowance for infancy is based on the amount of nutrients provided to healthy infants in human milk during the first six months of life and on the consumption of formula and increasing amounts of solid food during the second six months. The introduction of solid foods should parallel the developmental changes that occur within the central nervous system throughout the first year; these provide a level of readiness for the infant to manage foods of various textures from full liquid to soft. Even though significant technologic advances have led to changes in the way infants can be fed, human milk is still the optimal choice. Most women can be encouraged to breast-feed regardless of their own nutritional status or dietary intake. Contraindications can be managed on an individual basis. If women do not elect to breast-feed, suitable commercial formulas are available. The important issue in feeding is that of providing a variety of appropriately prepared foods offered in a nonjudgmental atmosphere so that the foundation is laid for the development of good food habits.     

Hurricane Hugo blows down the broccoli: Preschoolers' post-disaster play and adjustment

This article reports highlights from over 200 parents' observations of their preschoolers' play and verbalizations in the year following Hurricane Hugo. Commonly reported activities included reenactment and discussion of the event in multiple mediums, personification of Hugo, and expression of fears related to storms. Precocious concern for others, insight, and vocabulary were also noted. In these intact, relatively high functioning families, parents seemed able to facilitate their youngsters' adjustment without outside intervention.Portions of this report were presented in earlier form at the 1991 Society for Research in Child Development meeting in Seattle, Washington.     

Human eosinophils express and release IL-13 following CD28-dependent activation

Human eosinophils produce a large number of cytokines, including immunoregulatory cytokines. Given that eosinophils store and release interleukin (IL)-4, a key cytokine in the pathogenesis of allergic inflammation, and that IL-4 and IL-13 share common biological functions, we investigated the possibility that IL-13 may be synthesized by these cells. Using flow cytometry and immunocytochemistry, we show that eosinophils synthesize and store IL-13. Granule localization was demonstrated after subcellular fractionation, and IL-13 immunoreactivity was localized to crystalloid, granule-enriched fractions. Furthermore, electron microscopic analyses specifically localized IL-13 to the dense cores of bicompartmental secondary granules. Upon CD28 ligation, IL-13 was released by eosinophils, whereas a combination of CD28 and immunoglobulin A complexes resulted in decreased IL-13 secretion. Furthermore, eosinophil-derived IL-13 exerts a biological effect, inducing CD23 expression on B cells. By having the capacity to synthesize and release IL-13, eosinophils may participate in the development and maintenance of the T helper cell type 2 response, a prominent feature of allergic diseases.     

Canal-otolith interactions in the squirrel monkey vestibulo-ocular reflex and the influence of fixation distance

Natural head movements include angular and linear components of motion. Two classes of vestibulo-ocular reflex (VOR), mediated by the semicircular canals and otoliths (the angular and linear VOR, or AVOR and LVOR, respectively), compensate for head movements and help maintain binocular fixation on targets in space. In this study, AVOR/LVOR interactions were quantified during complex head motion over a broad range of fixation distances at a fixed stimulus frequency of 4.0 Hz. Binocular eye movements were recorded (search-coil technique) in squirrel monkeys while fixation distance (assessed by vergence) was varied using brief presentations of earth-fixed targets at various distances. Stimuli consisted of rotations around an earth-vertical axis and therefore always activated the AVOR. Horizontal and vertical AVORs were assessed when the head was centered over the axis of rotation and oriented upright (UP) and right-side-down (RD), respectively. AVOR gains increased slightly with increasing vergence in darkness, as expected given the small anterior position of the eyes in the head. Combined AVOR/LVOR responses were recorded when subjects were displaced eccentrically from the rotation axis. Eccentric rotations activated the AVOR just as when the head was centered, but added a translational stimulus which generated an LVOR component in response to interaural (IA) or dorsoventral (DV) tangential accelerations, depending on whether the head was UP or RD, respectively. When the head was eccentric and facing nose-out, the AVOR and LVOR produced ocular responses in the same plane and direction (coplanar and synergistic), and response magnitudes increased with increasing vergence. With the head facing nose-in, AVOR and LVOR response components were oppositely directed (coplanar and antagonistic). The AVOR dominated the response when fixation distance was far, and phase was compensatory for head rotation. As fixation distance decreased toward the rotation axis, responses declined to near zero, and when fixation distance approached even closer, the LVOR component dominated and response phase inverted. The same pattern was observed for both horizontal (head UP) and vertical (head RD) responses. The LVOR was recorded directly by rotating subjects eccentrically but in the nose-up (NU) orientation. The AVOR then generated torsional responses to head roll, coexistent with either horizontal or vertical LVOR responses to tangential acceleration when the subject was oriented head-out or right-side-out, respectively. Only the LVOR response components were modulated by vergence. A vectorial analysis of AVOR, LVOR, and combined responses supports the conclusion that AVOR and LVOR response components combine linearly during complex head motion. Received: 27 February 1997 / Accepted: 18 June 1997