Expression of macrophage markers by a population of T cells obtained from synovial fluid of a subgroup of patients with juvenile rheumatoid arthritis

OBJECTIVE: To characterize distinctive lymphoid cell populations in the synovial fluid (SF) of patients with juvenile rheumatoid arthritis (JRA) that have the specific ability to display monocytic markers when cultured in vitro. METHODS: Mononuclear cells obtained from SF of patients with JRA and depleted of adherent macrophages were cultured in vitro in RPMI 1640 medium supplemented with only fetal calf serum (FCS). Phenotypic evaluation of these cells was by flow cytometry and immunohistochemical analysis was by specific fluorochrome labeled antibodies. RESULTS: T cells from a JRA subgroup displayed some typical macrophage attributes, i.e., abundant cytoplasm, adherence to plastic, and phagocytosis of latex beads when cultured in vitro. These cells have the ability to survive in culture for several weeks in RPMI 1640 medium containing only 10% FCS. The macrophage-like T cells rosetted with sheep red blood cells and proliferated when stimulated with phytohemagglutinin or anti-CD3, indicating functional T cell responses. CONCLUSION: Our data indicate that a population of T cells obtained from the SF of a subgroup of patients with JRA exhibited characteristics of macrophages, yet retained their CD3 and T cell receptor expression. Whether this promiscuous behavior is caused by malignant transformation of lymphoid precursor cells or is induced by the concerted effect of a myriad of cytokines and growth factors present in the SF remains unknown. The presence of these cells in the SF of 2 patients with JRA with different onset types raises the question of their function and significance in an autoimmune disorder such as JRA.     

Prevalence of morphologic defects in spermatozoa from beef bulls

OBJECTIVE: To determine the overall prevalence of morphologic defects in spermatozoa from beef bulls and to determine whether prevalence varies with the age of the bull. DESIGN: Cross-sectional observational study. ANIMALS: 2,497 beef bulls that were evaluated for breeding soundness in 1994 by 29 practicing veterinarians in a 5-state geographic region. PROCEDURE: Slides of spermatozoa from each bull were made and submitted by practicing veterinarians for morphologic evaluation. One hundred spermatozoa per slide were examined, and each was classified as having 1 of 9 morphologic defects or as normal. RESULTS: 63% of bulls evaluated were 10 to 12 months old, and 20% were 13 to 18 months old. A mean of 70.6% of spermatozoa was classified as normal. Most common defects were proximal droplets (8.4%), distal midpiece reflexes (6.7%), separated heads (5.5%), and distal droplets (3.8%). Other defects were seen < 2% of the time. Bulls 10 to 12 months of age had a higher prevalence of proximal and distal droplet defects than older bulls. CLINICAL IMPLICATIONS: Practitioners conducting breeding soundness evaluations in beef bulls must be aware of common spermatozoal defects. Bulls that are evaluated at a young age will have more defects than older bulls and should be reevaluated, particularly for those defects for which prevalence decreases with age.     

Categorical perception effects induced by category learning

The authors report a series of studies designed to determine whether effects similar to those observed in the innate categorical perception of color and phonemes are induced during the learning of simple unidimensional categories and more complex multidimensional ones. In Experiment 1 no evidence was found for such effects when stimuli varied on 1 dimension. Experiments 2 and 3 demonstrated a within-category compression effect but no between category expansion effect for stimuli varying in 2 dimensions. Compression only was also shown in Experiment 4, which used pictures of actual objects. Multidimensional scaling analyses illustrate how within-category compression without expansion was sufficient to produce categorical clustering of items in the similarity space. These analyses also show that learning changed the dimensional structure of similarity space. Results are compared with those from other studies exploring similar phenomena and with neural network simulations.     

Increased micronucleus frequency in the progeny of irradiated Chinese hamster cells

V79 Chinese hamster cells were irradiated with doses of 1-12 Gy 300 kV X-rays. Their colony-forming ability and the frequency of micronuclei in binucleate cells after treatment with cytochalasin B was determined at various times after irradiation. The frequency of micronuclei determined within the first 24 h after irradiation increased with doses up to 4 Gy and decreased as the dose increased further. Up to 4 Gy there was a close correlation between surviving fraction and the fraction of cells without micronuclei although the surviving fraction was 2-3 times lower than the fraction of cells without micronuclei. Six, 10 or 13 days after irradiation with either 9 or 12 Gy the plating efficiency and the frequency of micronuclei after cytokinesis block with cytochalasin B was determined in the irradiated, but surviving, cells. The delayed plating efficiency of irradiated cells was significantly decreased. The proportion of binucleated cells was in the normal range at 6-13 days after irradiation, indicating that the proliferative activity of irradiated but surviving cells was not depressed at that time. The micronucleus frequency, however, was significantly increased at all times after irradiation. There was little heterogeneity of plating efficiency and micronucleus frequency among 12 clones which had been isolated for irradiated cultures, 3 weeks after 12 Gy.     

Evaluation of titanium brackets for orthodontic treatment: part I. The passive configuration

The static and kinetic frictional coefficients of commercially pure titanium brackets were evaluated in the passive configuration in the dry and wet states against stainless steel, nickel-titanium, and beta-titanium arch wires. For comparison, stainless steel brackets were evaluated under identical conditions. Titanium brackets were grayer in color and rougher in texture than the stainless steel brackets. Bracket slots were up to 0.002 inch greater than the nominally stated values. Remarkably, the static and kinetic frictional coefficients of the couples formed by titanium and stainless steel brackets were comparable. When evaluated against stainless steel and nickel-titanium arch wires in the dry state at 34 degrees C, the static coefficient averaged.12 and.20, respectively, independent of bracket alloy. When evaluated against stainless steel and nickel-titanium wires in the wet state at 34 degrees C using human saliva, the static coefficient averaged.15 and.20, respectively, independent of bracket alloy. Only the beta-titanium arch wires increased by about 15%, when tested in either the dry or the wet state against titanium versus stainless steel brackets. Noteworthy, too, was the decrease of both coefficients in the beta-titanium wire couples from their previously reported values. Analyses of electron spectroscopy for chemical analysis spectra and depth profiles show that these new brackets are titanium only in the bulk. Indeed the immediate surfaces are composed of, at least, 80 atomic percent (at.%) carbon and oxygen; whereas, the titanium that is present (>11 at.%) is mostly in the form of titanium dioxide. The presence of this quite thin passivating layer, which resides on top of an oxygen-hardened titanium substrate, reduces the galling and fretting that would normally be expected in such materials. Pending the outcome of future angulation tests, these frictional measurements show that titanium brackets are not only comparable to stainless steel brackets but also are more biocompatible with nickel having been eliminated from their constitution.     

Factors influencing survival after gamma knife radiosurgery for patients with single and multiple brain metastases

BACKGROUND: Significant changes are restructurng the U.S. health care delivery system. National health reform is now extending itself into the public sector. Increased health and medical costs by federal and state governments are forcing a reevaluation of major entitlement programs, especially Medicaid. METHODS/RESULTS: Because Medicaid is the single largest item in many state budgets, states are now enrolling Medicaid patients into managed and coordinated care arrangements as a means to control costs and increase access to care. HMOs are not only competing for private patients but also actively seeking the Medicaid population. Nationally, almost one-fourth of all Medicaid patients are now enrolled in managed care plans. Various models and approaches have been developed by individual states. CONCLUSIONS: Because managed care enrollment in the Medicaid program has increased substantially in recent years, selected services including vision care are no longer rendered by any practitioner willing to accept Medicaid fees. Freedom of choice is now restricted to pre-selected and panel practitioners participating with the managed care program. The rules, regulations, billing procedures, fees, and program requisites will differ under managed care programs. Private optometric practitioners must consider entering economic and organizational relationships and linkages that make them attractive to managed care organizations.     

Internet usage for information provisioning: theoretical construct development and empirical validation in the clinical decision-making context

Despite substantial discussion of the Internet's impact on individual activities, there is an absence of a theoretically grounded measure of Internet usage for the provisioning of information required by decision-makers. Our research addresses this void in the literature. We conceptualize Internet Usage for Information Provisioning (IUIP) as the degree to which the Internet is used to meet information requirements of individual decision-makers engaged in diagnostic decision-making tasks. Drawing on the information processing theoretical framework, three dimensions (usage for breadth of content, usage for depth of content, and usage for interaction dynamism) of IUIP are identified. The construct was validated through a two-phase empirical study conducted in the physician clinical decision-making context. The first phase involved interviewing physicians to establish face validity of the dimensions and to generate multi-item measures for each dimension. The second phase consisted of surveying physicians to evaluate measurement properties and nomological validity. Principal components analysis, confirmatory factor analysis, and partial least squares analysis were the primary statistical techniques used to analyze the data and evaluate construct validity. Our results suggest that decision-makers operating in uncertain and equivocal decision contexts use the Internet to a greater degree for their content needs and selective attention requirements. Our results also suggest that a fit between the user's information processing requirements and technology, and selected social norms, lead to higher levels of IUIP. Implications for practice and future research are discussed.