Promoting Smoke-Free Homes: A Novel Behavioral Intervention Using Real-Time Audio-Visual Feedback on Airborne Particle Levels

Interventions are needed to protect the health of children who live with smokers. We pilot-tested a real-time intervention for promoting behavior change in homes that reduces second hand tobacco smoke (SHS) levels. The intervention uses a monitor and feedback system to provide immediate auditory and visual signals triggered at defined thresholds of fine particle concentration. Dynamic graphs of real-time particle levels are also shown on a computer screen. We experimentally evaluated the system, field-tested it in homes with smokers, and conducted focus groups to obtain general opinions. Laboratory tests of the monitor demonstrated SHS sensitivity, stability, precision equivalent to at least 1 µg/m³, and low noise. A linear relationship (R² = 0.98) was observed between the monitor and average SHS mass concentrations up to 150 µg/m³. Focus groups and interviews with intervention participants showed in-home use to be acceptable and feasible. The intervention was evaluated in 3 homes with combined baseline and intervention periods lasting 9 to 15 full days. Two families modified their behavior by opening windows or doors, smoking outdoors, or smoking less. We observed evidence of lower SHS levels in these homes. The remaining household voiced reluctance to changing their smoking activity and did not exhibit lower SHS levels in main smoking areas or clear behavior change; however, family members expressed receptivity to smoking outdoors. This study established the feasibility of the real-time intervention, laying the groundwork for controlled trials with larger sample sizes. Visual and auditory cues may prompt family members to take immediate action to reduce SHS levels. Dynamic graphs of SHS levels may help families make decisions about specific mitigation approaches.     

Prions and lymphoid organs: Solved and remaining mysteries

Prion colonization of secondary lymphoid organs (SLOs) is a critical step preceding neuroinvasion in prion pathogenesis. Follicular dendritic cells (FDCs), which depend on both tumor necrosis factor receptor 1 (TNFR1) and lymphotoxin β receptor (LTβR) signaling for maintenance, are thought to be the primary sites of prion accumulation in SLOs. However, prion titers in RML-infected TNFR1^−/− lymph nodes and rates of neuroinvasion in TNFR1^−/− mice remain high despite the absence of mature FDCs. Recently, we discovered that TNFR1-independent prion accumulation in lymph nodes relies on LTβR signaling. Loss of LTβR signaling in TNFR1^−/− lymph nodes coincided with the de-differentiation of high endothelial venules (HEVs)—the primary sites of lymphocyte entry into lymph nodes. These findings suggest that HEVs are the sites through which prions initially invade lymph nodes from the bloodstream. Identification of HEVs as entry portals for prions clarifies a number of previous observations concerning peripheral prion pathogenesis. However, a number of questions still remain: What is the mechanism by which prions are taken up by HEVs? Which cells are responsible for delivering prions to lymph nodes? Are HEVs the main entry site for prions into lymph nodes or do alternative routes also exist? These questions and others are considered in this article.     

Antigenic determinants expressed by human C4 allotypes; a study of 325 families provides evidence for the structural antigenic model

The antigenic determinants of human C4 have been defined by human IgG antisera, Rodgers (Rg) and Chido (Ch), in hemagglutination-inhibition assays (HAI). Eight (2 Rg and 6 Ch) are of high frequency, > 90% , and 1, WH, is of low frequency, 15 %. The phenotypic combinations are complex; generally, C4A expresses Rg, and C4B has Ch, but reverse antigenicities have been established both by HAI and by sequence data of selected C4 allotypes. A study of 325 families provides data on the antigenic expression of each C4 allotype and demonstrates strong associations. A structural model for the antigenic determinants of C4 proteins has been proposed and is completely supported by the family material. Of the 16 possible antigenic combinations for C4 proteins, only 3 are undetected. A new Ch combination has been recorded in two French families. The reported sequence variation within the C4d region can account for the antigenic determinants but leaves the location of electrophoretic variation in C4 still unclear.     

Transgenic turf-type tall fescue (Festuca amndinacea Schreb.) plants regenerated from protoplasts

To improve turfgrasses using genetic engineering, we have developed a transformation system in turf-type tall fescue, one of the most important turfgrass species. Embryogenic cell cultures were established after callus induction from embryos of mature seed. The agarose-bead method with nurse cells was used to culture protoplasts and plants were regenerated from protoplasts of tall fescue cultured cells. To develop transgenic tall fescue plants, the hygromycin resistance gene and the -glucuronidase gene were introduced into the tall fescue protoplasts by electroporation. A high concentration (200 mg/l) of hygromycin was required to select transformed cells because of the high level of endogenous resistance to the antibiotic in tall fescue. Most of the transformed cells exhibited GUS activity and several plants were regenerated from these cells. The presence of introduced genes was confirmed by Southern blot hybridization of PCR amplified DNA from transgenic plants.Abbreviations Adh alcohol dehydrogenase - BAP benzylaminopurine - bp base pair(s) - GUS -glucuronidase - Kb kilobase(s) - MS Murashige and Skoog's medium - PCR polymerase chain reaction     

Ion exchange process for removing glucosyltransferase from crude glucoamylase

The advant of a new range of high-protein capacity cellulosic ion exchangers suitable for use on an industrial scale made it worthwhile investigating the conditions necessary to remove the contaminating enzyme glucosyltransferase from a commercial preparation of crude glucoamylase. The potential of the SP derivative, SP Indion((R)), for achieving this separation is shown. At pH 2.5 the glucosyltransferase was selectively adsorbed by the ion exchanger, and 99% of the glucoamylase was recovered in the eluate from the column. Purification of an Aspergillus culture filtrate by this method will require careful control of the ionic strength of the culture medium if it is to be used without the additional step of cation exchange to lower than pH to 2.5.     

Physical and biotic determinants of space utilization by the Galapagos land iguana (Conolophus pallidus)

Summary Home ranges of the Galapagos land iguana (Conolophus pallidus) were examined with respect to food availability and the thermal environment. Activity patterns, the amount of space used per day, and time required to use the entire home range were also investigated. The effects of, and the relationships between, these factors vary seasonally, as do home range sizes and preferred body temperatures.Food supplementation experiments resulted in only temporary reductions in use of space. Home range sizes were not different between the seasons with the least (Fall) and the most (Hot) food availalble, but home ranges were significantly smaller in Garua when food supplies were low, but not as low as in Fall. Calculations of metabolic expenditures in each season suggests that food availability alone does not explain seasonal patterns of home range size in this species.The thermal environment within each home range was characterized by microclimatic measurements and measurements of the area of sun, shade, and semi-shade. An index with units of m²h was used to quantify the thermal quality of each home range. Iguanas exploited optimal (with respect to body temperature) conditions more than would be expected from random use of their home ranges. Thermal transients (due to large body size) and optimal conditions were exploited to the largest degree in Fall.During Garua, low metabolic rates and time constraints imposed by an abundance of stressful thermal environments may result in small home ranges. In Fall, increased temperatures cause higher metabolic rates and allow more time for exploitation of the cooler portions of the home range, hence, home range sizes increase. In the Hot season, there is abundant food and optimal thermal conditions, but home ranges remain large. Searching for preferred foods may cause the large home ranges in this season.     

"Clotspeed," a mathematical simulation of the functional properties of prothrombinase

Prothrombinase is a Ca2+-dependent, 1:1, enzymatic complex of Factor Xa and Factor Va that assembles on the surface of negatively charged phospholipid vesicles or platelets. It catalyzes the proteolytic conversion of prothrombin to the blood-clotting enzyme thrombin. Experimentally determined kinetic parameters, plus Kd and n values for the interaction of substrate, cofactor (Factor Va), and serine protease (Factor Xa) for both phospholipid and each other, were used to develop a model that simulates the functional properties of the enzymatic complex. Through the use of a desk-top computer and a program designated "Clotspeed," the distribution of enzymatic components and substrate between the bulk fluid and phospholipid is determined for a given set of initial concentrations of reaction components. Simulated reaction rates are then calculated from the calculated distributions, fractional binding, and local and bulk concentration of reactants. Predicted behavior includes formal Michaelis-Mentenlike properties for the reaction, increasing apparent Km with increased levels of phospholipid, and apparent inhibition by excess substrate, enzyme, and phospholipid. Inhibition by excess enzyme and phospholipid was demonstrated experimentally in quantitative agreement with predicted results. The model is useful in that it rationalizes well the seemingly unusual properties of prothrombinase in straightforward physical terms, provides a means of rationally choosing experimental conditions to both further test and refine the model, and explores the properties not only of prothrombinase but also other blood-clotting or surface-bound enzymatic complexes.     

Cytogenetic analysis of chorionic villi: a technical assessment

Summary Eighty-five samples of chorionic villi from women undergoing prenatal diagnosis at 8 to 12 weeks' gestation were subjected to cytogenetic analysis. Samples were prepared by a direct technique that permits limited analysis within two hours and by a short-term culture technique that permits detailed structural analysis within one week. An adequate number of cell divisions for cytogenetic analysis was obtained from 96% of living fetuses. Using both the direct technique and short-term culture, satisfactory banded chromosomal preparations were made in 93% of cases. Eleven of 12 pregnancies (92%) shown by ultrasound to be dead shortly before sampling, had cytogenetic abnormalities. Further studies are needed to develop banding definition equivalent to that available on cultured amniocytes.     

Exudation of amino acids by intact and damaged roots of wheat and peas

Summary Wheat and pea seedlings were grown aseptically in solution-culture and the total free amino nitrogen released by the roots was determined by a quantitative ninhydrin test. Amino nitrogen from wheat plants after 14 days growth was not detected by the test, indicating the release of less than 3 µg of amino nitrogen from a culture of 15 plants. Pea plants of the same age released from 2 to 7 µg per plant. Paper chromatograms of highly concentrated undisturbed solution-cultures revealed up to 13 amino compounds from wheat and 11 from pea. The pattern of amino acids in exudates was similar to that in crushed roots, except for an unidentified amino compound which was detected only in exuded material. The total amino nitrogen and relative proportions of several amino acids in the root exudates of sand-grown peas was influenced by several ratios of oxygen and carbon dioxide supplied to the root zone. Roots, experimentally damaged by swirling and rinsing in sand, released in 1 hour amino nitrogen of from 73 to 120 per cent of that released by normal exudation over a 2-week period. Our findings suggest that experimental and environmental root damage may be responsible for a large proportion of organic materials released by growing plant roots.Trade names are used in this publication to provide specific information. Their use does not constitute a guarantee of the products named and does not signify that they are approved by the U.S. Department of Agriculture to the exclusion of others of suitable composition.     

Lectin binding characterstics of mouse epididymal fluid and sperm extracts

Glycoproteins from luminal fluid of the mouse cauda epiciidymidis have been compared with glycoproteins from Triton X-100 extracts of mouse spermatozoa from varying regions of the epididymis, using lectins with specific affinity for different sugar residues. Concanavalin A recognizes 11 glycocomponents on Western blots of fractionated caudal fluid; wheat germ agglutinin (WGA) binds 12 proteins; Ulex europaeus agglutinin (UEA) binds seven; and Dolichos biflorus agglutinin (DBA) recognizes nine. Several of these glycoproteins display an affinity for more than one lectin, indicating a diversity in their exposed carbohydrate residues; whereas other proteins bind only one of the four lectins used. The results also show that some glycoproteins exhibit a higher affinity for particular lectins. Eight glycoproteins of similar mobility and lectin-binding characteristics are detected in Triton X-100 extracts of spermatozoa from different regions of the epididymis and in caudal fluid. The lectin affinity of some proteins appears or increases in spermatozoa from distal epididymal regions (54 kD, 32 kD), whereas the lectin affinity of others decreases (29 kD, 40 kD). There are differences in lectin affinities between proteins in sperm extracts and in caudal fluid. Some proteins show an affinity for three or four lectins in caudal fluid, but proteins of similar electrophoretic mobility in sperm extracts bind only one or two of the lectins. These data show that glycoproteins of similar mobility are present in caudal fluid and in Triton-X-100 sperm extracts, implying a potential interaction between caudal fluid components and epididymal sperm.