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Sickle cell disease (SCD) is a lifelong disorder that involves progressive organ damage and requires ongoing medical attention to prevent and treat episodic acute complications. Children with SCD need ongoing monitoring and extra attention that may be stressful to family members. Communication within families can help resolve family stress and may be associated with medical follow-up and management of SCD. Focus groups were conducted with 12 African American families to explore the communication that occurred within and outside of the family from the perspectives of adolescents with SCD, siblings, and parents. Factors that influence family communication were explored. The extended family was an important social network and resource to adolescents, siblings, and parents. Family member knowledge of SCD was an important factor that influenced communication about SCD; adolescents and parents communicated more easily than siblings and also reported having more knowledge of SCD than siblings. Future research focusing on the knowledge of immediate and extended family members and their recognition of their contribution to the child with SCD is recommended.

Background: The estimated prevalence of Autism Spectrum Disorder (ASD) is one in 88. Autism Spectrum Disorders are nearly five times more common among boys than girls. Children with autism may develop a variety of socially unacceptable maladaptive behaviors beyond the defining symptoms of the spectrum disorder., Aims: It is necessary to conduct research to examine maladaptive behaviors of children with autism, family supports, parental stress, and parental coping., Methods: Data used were collected during an earlier descriptive, correlational, cross-sectional study. Using the Double ABCX Model of family behavior as the framework, this study evaluated parents' views of the adaptive behaviors of their children diagnosed with autism using the networks of support for their family, parental stress, and parental coping patterns., Results: Results indicate an association between increased Internalizing maladaptive behaviors and increased parental stress (r = .547, p = .000)., Conclusions: The findings of this study suggest that parents of children with autism report that their children have clinically significant maladaptive behaviors. Healthcare providers could use results from this study to provide appropriate intervention for maladaptive behaviors to support children with autism and their families.

Background: Research suggests that parents of children with disabilities endure increased amounts of stress but also experience positive outcomes., Purpose: To further investigate findings from focus group interviews that explored parental stress in families of children with disabilities using a sequential mixed methods design., Method: This study sought to model parental stress using the McCubbin and McCubbin (1993) Resiliency Model of Stress, Adjustment, and Adaptation using qualitative and quantitative data collected sequentially. Twenty-five parents of children with autism spectrum disorder, cerebral palsy, Down syndrome, and sickle cell disease participated in a 2-step study that encompassed qualitative followed by quantitative data ascertainment., Results: Parents who quantitatively experienced high stress or low stress used different behavioral themes to describe their experience qualitatively. Positive appraisals, resources, and ability to engage in problem solving and coping were associated with family resiliency.

γδ T cells function in innate and adaptive immunity and are primed for secondary responses by procyanidin components of unripe apple peel (APP). In this study, we investigate the effects of APP and purified procyanidins on γδ T-cell gene expression. A microarray analysis was performed on bovine γδ T cells treated with APP; increases in transcripts encoding granulocyte-monocyte colony stimulating factor (GM-CSF), IL-8 and IL-17, but not markers of TCR stimulation such as IFNγ, were observed. Key responses were confirmed in human, mouse and bovine cells by reverse transcription-PCR and/or ELISA, indicating a conserved response to procyanidins. In vivo relevance of the cytokine response was shown in mice following intraperitoneal injection of APP, which induced production of CXCL1/KC and resulted in neutrophil influx to the blood and peritoneum. In the human T-cell line, MOLT-14, GM-CSF and IL-8 transcripts were increased and stabilized in cells treated with crude APP or purified procyanidins. The ERK1/2 MAPK pathway was activated in APP-treated cells, and necessary for transcript stabilization. Our data describe a unique γδ T-cell inflammatory response during procyanidin treatment and suggest that transcript stability mechanisms could account, at least in part, for the priming phenotype.

Background: As the number of children diagnosed with autism continues to rise, resources must be available to support parents of children with autism and their families. Parents need help as they assess their unique situations, reach out for help in their communities, and work to decrease their stress levels by using appropriate coping strategies that will benefit their entire family., Methods: A descriptive, correlational, cross-sectional study was conducted with 75 parents/primary caregivers of children with autism. Using the McCubbin and Patterson model of family behavior, adaptive behaviors of children with autism, family support networks, parenting stress, and parent coping were measured., Findings and Conclusions: An association between low adaptive functioning in children with autism and increased parenting stress creates a need for additional family support as parents search for different coping strategies to assist the family with ongoing and new challenges. Professionals should have up-to-date knowledge of the supports available to families and refer families to appropriate resources to avoid overwhelming them with unnecessary and inappropriate referrals.

Forty-five parents of children with autism, cerebral palsy, Down syndrome, and sickle cell disease participated in 8 focus groups. Parents discussed how they, the child with the disability, and the siblings addressed community perceptions about the child's disability. Themes evolving from the interviews included (a) support and lack of support, (b) inclusion and exclusion, and (c) the family members' roles during their interactions with the community. Parents viewed their roles in the community as (a) advocating, (b) educating, (c) informing, (d) ignoring, and (e) hiding. The relationship between themes is presented, and the relationship between themes and parent empowerment is discussed as well as the ways in which the themes reflect underlying ableism.

Background: Communication within families of children with sickle cell disease is important yet has not been adequately investigated., Methods: Focus group interviews were conducted with parents of children with sickle cell disease to explore parent-sibling communication about sickle cell disease., Results: Communication was influenced by attributes and behaviors of the parent, the child with sickle cell disease, and the sibling; extended family, neighbors, friends, and church members or social networks; and available, accessible resources related to the child's health, child's school, and parent employment. Outcomes that influenced and were influenced by factors within and outside the parent-sibling dyad and nuclear family included parent satisfaction, parent roles, family intactness, and status attainment., Conclusions: These findings support previous research with African-American families and expand our views of the importance of educating parents, family members, and others about sickle cell disease. The findings suggest a need to explore sibling perception of this communication, parent and sibling perception of the impact of frequent hospitalizations and clinic visits on the sibling and family, and variations within families of children with sickle cell disease.

Background: Forty studies performed between 1970 and 1995 indicated that 60% of parents with children with developmental disabilities reported manifestations of increased risk or negative effects on the well siblings., Method: A secondary data analysis was performed using qualitative data gathered during the baseline of a randomized controlled clinical trial of an intervention for siblings/families of children with long-term conditions, including developmental disabilities. Content analysis was used to identify themes from responses of 151 parents to an open-ended question on their perceptions of the effects on well siblings of living at home with a brother/sister with developmental disabilities., Results: Of 363 themes identified, 61.1% reflected negative manifestations of increased risk in well siblings; 1.7% indicated no risk; and 37.2% reflected positive outcomes, suggesting the continued need for potential interventions., Conclusion: Contemporary family life in these families, as portrayed by parents' descriptions, reflects need in child health care for more intervention research on this vulnerable population.

A pilot study was conducted using a focus group interview with parents of children with autism to provide parents with the opportunity to express their concerns related to parenting a child with autism and to discuss strategies parents can use to manage these challenges. Parents' desire and need for information related to autism is evident. Parents' identified supports and resources in need of expansion and development to assist with their child's needs. These findings support previous research with families communicating a need for partnership with healthcare providers. Nurses are often the first contact with children with autism and their families; they can support the partnership between parents and healthcare professionals. Using the Double ABCX Model of family behavior as the conceptual framework, a study investigating the findings of this pilot study has been completed.

Yamoa (ground bark of Funtumia elastica tree) is marketed and sold as a dietary supplement with anecdotal therapeutic effects in the treatment of asthma and hay fever. We determined that Yamoa and Yamoa-derived polysaccharides affected innate immunity, in part, by priming gammadelta T cells. Gene expression patterns in purified bovine gammadelta T cells and monocytes induced by Yamoa were similar to those induced by ultrapure lipopolysaccharide (uLPS). In the presence of accessory cells, Yamoa had priming effects that were similar to those of LPS on bovine and murine gammadelta T cells, but much more potent than LPS on human gammadelta T cells. The bioactive component of Yamoa was delineated to a complex polysaccharide fraction (Yam-I). Intraperitoneal injection of Yamoa and Yam-I in mice induced rapid increases in peritoneal neutrophils directed by changes in chemokine expression. In support of a unique agonist found in Yam-I, similar peritonitis responses were also observed in TLR4- and MyD88-deficient mice. Therapeutic treatment with Yam-I resulted in decreased bacterial counts in feces from mice with Salmonella enterica serotype typhimurium (ST)-induced enterocolitis. This characterization of the immune stimulatory properties of polysaccharides derived from Yamoa suggests mechanisms for the anecdotal positive effects of its ingestion and that these polysaccharides show potential for application in innate protection from disease.

This qualitative study identified communication themes among well siblings, parents, and others within families of children with chronic conditions. Semi-structured interviews of 30 parent-well sibling dyads were content analyzed from a larger study of families of children with chronic conditions. Four themes emerged: communication as a reflection of family roles and relationships, giving voice, staying connected, and struggling for normalcy.

Colletotrichum dematium is an endophytic fungus recovered from a Pteromischum sp. growing in a tropical forest in Costa Rica. This fungus makes a novel peptide antimycotic, colutellin A, with a MIC of 3.6 microg ml(-1) (48 h) against Botrytis cinerea and Sclerotinia sclerotiorum. Collutellin A has a mass of 1127.7 Da and contains residues of Ile, Val, Ser, N-methyl-Val and beta-aminoisobutryic acid in nominal molar ratios of 3 : 2 : 1 : 1 : 1, respectively. Independent lines of evidence suggest that the peptide is cyclic and sequences of Val-Ile-Ser-Ile and Ile-Pro-Val have been deduced by MS/MS as well as Edman degradation methods. Colutellin A inhibited CD4(+) T-cell activation of interleukin 2 (IL-2) production with an IC(50) of 167.3+/-0.38 nM, whereas cyclosporin A in the same test yielded a value of 61.8 nM. Inhibition of IL-2 production by collutellin A at such a low concentration indicates the potential immunosuppressive activity of this compound. In repeated experiments, cyclosporin A at or above 8 microg ml(-1) exhibited high levels of cytotoxicity on human peripheral blood mononuclear cells, whereas collutellin A or DMSO (carrier) alone, after 24 and 48 h of culture, exhibited no toxicity. Because of these properties collutellin A has potential as a novel immunosuppressive drug.

Analysis of global gene expression in immune cells has provided unique insights into immune system function and response to infection. Recently, we applied microarray and serial analysis of gene expression (SAGE) techniques to the study of gammadelta T-cell function in humans and cattle. The intent of this review is to summarize the knowledge gained since our original comprehensive studies of bovine gammadelta T-cell subsets. More recently, we have characterized the effects of mucosal infection or treatment with microbial products or mitogens on gene expression patterns in sorted gammadelta and alphabeta T-cells. These studies provided new insights into the function of bovine gammadelta T-cells and led to a model in which response to pathogen-associated molecular patterns (PAMPs) induces 'priming' of gammadelta T-cells, resulting in more robust responses to downstream cytokine and/or antigen signals. PAMP primed gammadelta T-cells are defined by up-regulation of a select number of cytokines, including MIP1alpha and MIP1beta, and by antigens such as surface IL2 receptor alpha (IL-2Ralpha) and CD69, in the absence of a prototypic marker for an activated gammadelta T-cell, IFN-gamma. Furthermore, PAMP primed gammadelta T-cells are more capable of proliferation in response to IL-2 or IL-15 in the absence of antigen. PAMPs such as endotoxin, peptidoglycan and beta-glucan are effective gammadelta T-cell priming agents, but the most potent antigen-independent priming agonists defined to date are condensed oligomeric tannins produced by some plants.

Family involvement in planning and choosing services has become a key intervention concept in developmental disability services. This study (N = 547) modeled patterns of family decision making and assessed benefits to persons with developmental disabilities (DDs) and their family members. A latent profile analysis identified 4 classes that were highly involved in decision making (n = 118), involved only in planning (n = 166), involved only in financial decisions (n = 75), and uninvolved (n = 188). Multiple regression analysis indicated that consumers with DD whose family members were highly involved received more services than consumers in other families. A multivariate analysis of covariance indicated that the family members in the highly involved and planning classes experienced more family member satisfaction than others. Findings have implications for practice.

Leukocyte adhesion and migration are mediated partially by CD11b/CD18 (membrane-activated complex-1, CR3). Earlier studies have demonstrated a role for green tea polyphenols in down-regulating CD11b on CD8(+) T cells and monocytes. We have shown recently a stimulatory effect of unripe apple polyphenols (APP) on gammadelta T cells. Thus, we compared the effect of APP on bovine gammadelta T cell and monocyte CD11b expression. Purified bovine monocytes and monocyte-depleted PBLs were cultured with APP. CD11b levels decreased on monocytes in response to APP. In contrast, a gammadelta T cell subset responded to APP by up-regulating CD11b. The CD11b regulation was not seen on gammadelta T cells or monocytes treated with APP fractions depleted of tannins. The APP-induced down-regulation of CD11b on monocytes was inhibited by an anti-CD11b mAb, consistent with previous studies showing that polyphenols bind CD11b. As expected, the anti-CD11b mAb had no effect on the APP response in resting gammadelta T cells, as these cells lacked CD11b. Consistent with the changes in surface CD11b expression, APP-treated gammadelta T cells showed increased adherence to plastic, whereas monocyte adhesion was reduced. APP also induced cytokine gene expression in gammadelta T cells. Some polyphenols are thought of as anti-inflammatory agents; however, these data, as well as other ongoing studies, indicate they have a proinflammatory effect on gammadelta T cells. In vivo, plant polyphenols may enhance gammadelta T cell migration and function at sites of inflammation, where they could induce rapid, immune-regulatory and innate-like immune responses.

Gammadelta T cells have been conserved since the adaptive immune system arose, yet their importance is still unclear. In an attempt to compensate for the lack of a broad knowledge base of gammadelta T cells across species, global analyses of gammadelta T cell transcriptomes have been performed using serial analysis of gene expression (SAGE). Twelve new SAGE libraries were generated from the following bovine lymphocyte populations: magnetic bead-sorted blood gammadelta T cells, spleen gammadelta T cells and enriched spleen alphabeta T cells from a single calf, both rested and Con A/IL2 stimulated, and flow cytometry-sorted blood gammadelta and alphabeta T cells each either rested, Con A/IL2, or phorbol 12 myristate 13-acetate/ionomycin stimulated. These new libraries complement two earlier SAGE libraries of circulating gammadelta T cell subsets. These databases were analyzed using new web-based bioinformatic tools, which allow the user to rapidly compare gene expression patterns within these and other SAGE and standard expressed sequence tag libraries generated from different cell types and different species. These analyses revealed striking differences between blood and spleen gammadelta T cells and how these cells respond to mitogenic stimulation. These analyses also confirm previous studies that suggested that global gene expression in gammadelta and alphabeta T cells is quite similar; however, a 5-fold increase in gammadelta T cell-specific transcripts could be induced by Con A/IL2 stimulation. These new public databases provide additional resources for the annotation/analysis of global gene expression in gammadelta T cells, which will facilitate studies of the biology of this enigmatic lymphoid cell.

Objective: Siblings of children with chronic illness or disability have been reported to have a 1.6 to 2.0 risk for behavioral and mental health problems. Our objective was to examine the effects of an intervention for siblings (age 7-15 years) of children with chronic illness or disability., Method: A randomized, three-group repeated-measures design was used: full intervention (n=79), partial intervention (n=71), and a waiting list control group (n=102). Outcomes were sibling knowledge about illness, behavior problems, social support, self-esteem, attitude, and mood measured over four postintervention periods. Covariates were family cohesion, maternal mood, socioeconomic status, and well sibling age. The full intervention included structured teaching and psychosocial sessions at a 5-day residential summer camp. The partial intervention included camp only. Treatment effects were estimated by using generalized estimating equation panel analyses., Results: The full treatment group showed significant improvements on all six outcomes over most periods, the partial treatment group on three outcomes, and the control group on two outcomes. Improvements in outcomes ranged from 5% to 25% increases over baseline measures., Conclusions: A dose-response relationship to intervention was found. Treatment gains were sustained over a period of 12 months.

Child rearing in the New Independent States (NIS) is explored through a literature review examining child rearing practices in the former Union of Soviet Socialist Republics and the NIS. As exchanges between the NIS and other countries are underway, this information will help nurses understand issues faced by citizens of the NIS, families immigrating from the NIS, and health care professionals visiting the NIS. This review raises questions about NIS child rearing practices and may serve as a stimulus for further exploration of issues related to the health of children and families living in or emigrating from the NIS.

Students with special health care needs present challenges to persons involved with their education, but school staff are accepting the challenge to create safe, nurturing, and stimulating environments for these students. This article proposes guidelines for school staff working with students having special health care needs. The guidelines evolved from the authors' experiences and are child-related, family-related, and school-related. Discussion of each guideline includes illustrations of issues arising from them. Considerations for implementing the guidelines are presented and include discussion of school policies and procedures and state laws and regulations related to school staff working with students having special health care needs.

The kinetics of transport of the non-metabolizable hexose, 3-O-methyl-D-glucose, have been measured in Novikoff rat hepatoma cells by both zero-trans entry and equilibrium exchange procedures. Transport conformed to a simple carrier model which operates symmetrically with respect to direction, but with greater mobility of the loaded than of the empty carrier. Although a complete kinetic description of the transporter can, in theory, be obtained by application of integrated equations describing the time course of substrate equilibrium across the membrane beginning from the zero-trans situation, statistical analysis of hypothetical data indicated that directional asymmetry or differential mobilities of loaded and empty carrier cannot be discerned reliably from such data alone. The difference in mobility of loaded and empty carrier, apparent in a comparison of zero-trans entry and exchange data, ranged from 1.5--7-fold in different batches of cells. It is concluded that the magnitude of the difference is not an inherent property of the transporter, but is determined physiologically, and may be involved in regulation of hexose transport.

Detailed time courses of uptake of labeled 3-O-methyl-D-glucose and 2-deoxy-D-glycose by untreated and ATP-depleted Novikoff rat hepatoma cells were determined as function of concentration (0.2-10 mM) by a rapid mixing/sampling technique which allows uptake measurements in time intervals as short as 1.5 seconds. Intracellular accumulation of 3-O-methylglucose in untreated and ATP-depleted cells and of deoxyglucose in ATP-depleted cells to equilibrium followed pseudo-first order kinetics and initial velocities were computed from overall time courses of substrate accumulation. Initial velocity was a Michaelis-Menten function of exogenous substrate concentration. The estimated kinetic constants for zero-trans transport of 3-O-methylglucose were about the same for untreated and ATP-depleted cells (Kztm = 1.73 +/- 0.24 mM; Vztmax = 28.8 +/- 3.6 pmoles/microliter cell H2O. sec) and were similar to those for deoxyglucose transport in ATP-depleted cells (Kztm = 0.65 +/- 0.1 mM; Vztmax = 19.6 +/- 1.6 pmoles/microliter cell H2O. sec). Similar kinetic parameters were obtained for the transport of D-glucose and D-galactose in ATP-depleted cells. The transport of 3-O-methylglucose and deoxyglucose were inhibited by each other in a simple competitive manner with apparent Ki's similar to their transport Km's. In untreated cells, in which deoxyglucose was phosphorylated, intracellular steady-state levels of free deoxyglucose accumulated within 10 to 20 seconds of incubation regardless of its concentration in the medium. Thereafter, the rate of deoxyglucose incorporation into total cell material reflected the rate of phosphorylation rather than the transport rate. The rate of deoxyglucose transport exceeded the initial rate of its phosphorylation by 20-40 %. The intracellular steady-state-levels observed during the first 2 minutes of incubation decreased from about 40% of equilibrium level at 0.2 mM deoxyglucose to about 8% at 10 mM. Computer fits of a kinetic equation describing transport and phosphorylation as independent processes operating in tandem to these data are consistent with the observed kinetic constants for hexose transport and hexokinase activity with deoxyglucose as substrate. Upon longer incubation (2-10 minutes) the rate of deoxyglucose uptake by the phosphorylating cells decreased progressively, concomitant with a decrease in intracellular ATP and an increase in intracellular deoxyglucose to equilibrium levels. It is demonstrated that the rate of deoxyglucose uptake, measured at two or more minutes, seriously underestimates the hexose transport rate and yields misleading conclusions regarding the extent and type of inhibition by transport inhibitors, such as persantin or cytochalasin B. Persantin inhibited hexose transport in a simple non-competitive manner (Ki = 20 muM) indicating that the drug affects the function of the hexose carrier.

Inosine dialdehyde (INOX), the periodate oxidation product of inosine, inhibited the proliferation of various tumor cell lines in suspension culture in a concentration-dependent manner. A concentration of about 1 mM was required to completely inhibit the proliferation of Novikoff rat hepatoma and mouse L-cells, whereas about 0.1 mM completely inhibited the proliferation of L1210 and P388 mouse leukemia and Chinese hamster ovary cells. INOX inhibited in a similar time- and concentration-dependent manner the synthesis of protein, RNA, and DNA, as measured by the incorporation of labeled amino acid, uridine, and thymidine, into acid-insoluble material, without significantly affecting the incorporation of these precursors into the acid-soluble pool. Flow microfluorometric analyses showed that many of the INOX-treated cells became arrested in G2 + M. The results are consistent with the view that INOX affects multiple metabolic steps. The effects of INOX were quite different from those caused by typical inhibitors of ribonucleotide reductase, hydroxyurea, and 2,3-dihydro-1H-pyrazolo(2,3-a)imidazole, which very rapidly inhibited DNA synthesis and caused arrest of the cells in G1, with minimal effects on RNA and protein synthesis.

The nonmediated permeation of L-glucose, cytosine, and prednisolone into Novikoff rat hepatoma cells followed first order kinetics with rate constants of 0.00404, 0.173, and 2.4 min-1, respectively. The constants were estimated from a nonlinear least squares fit of the integrated first order rate equation. The rate constants were independent of substrate concentration and correlated with the partition coefficients of the substances in octanol-balanced salt solution (0.00158, 0.0352, and 17.8, respectively) and olive oil-balanced salt solution mixtures which were between 10- and 100-fold lower. Arrhenius plots for the permeation of L-glucose, cytosine, and prednisolone were linear and indicated activation energies of 24.2, 28.0, and 19.6 kcal/mol, respectively. The permeation of L-glucose and cytosine, but not of prednisolone, was impeded in a concentration-dependent manner by the presence of cytochalasin B and Persantin, heretofore thought of as specific inhibitors of facilitated diffusion processes. The relative degree of decrease of the permeation rates of L-glucose and cytosine, however, differed for cytochalasin B and Persantin.

2-Amino-3-(hydroxynitrosoamino)propionic acid (alanosine), at a concentration as low as 2.7 muM, completely inhibits the incorporation of hypoxanthine into adenosine triphosphate by cultured Novikoff rat hepatoma cells. Alanosine inhibits the first step in the conversion of inosine monophosphate to adenosine monophosphate because inosine monophosphate, but not adenylosuccinate, accumulates in treated cells. However, the alanosine inhibition is not prevented by aspartic acid, even at a concentration of 1 mM. Alanosine treatment results in the inhibition of cell division, DNA synthesis, RNA and protein synthesis (in this order), and a depletion of the cells of adenosine triphosphate. Some of the cells accumulate in late G2 or M, but the remainder become arrested in other stages of the cell cycle. All effects are due to the inhibition of adenosine monophosphate synthesis and the consequent depletion of the adenosine triphosphate pool since they are completely prevented or reversed by addition of adenine, but not hypoxanthine, to the medium. Pyrimidine nucleotide synthesis is not significantly inhibited by alanosine, since the uridine triphosphate pool is not affected and uridine fails to reverse the cytotoxicity of alanosine. Alanosine also inhibits the transport of aspartic acid, but has a much lower affinity for this transport system than aspartic acid.

6-Mercaptopurine and 6-thioguanine strongly inhibited the zero-trans entry of hypoxanthine into Novikoff rat hepatoma cells which lacked hypoxanthine/guanine phosphoribosyltransferase, whereas 8-azaguanine had no significant effect. 6-Mercaptopurine was transported by the hypoxanthine carrier with about the same efficiency as its natural substrates (Michaelis-Menten constant = 372 +/- 23 microM; maximum velocity = 30 +/- 0.7 pmol/microl cell H2O per s). 8-Azaguanine entry into the cells, on the other hand, showed no sign of saturability and was not significantly affected by substrates of the hypoxanthine/guanine carrier. The rate of entry of 8-azaguanine at 10-100 microM amounted to only about 5% of that of hypoxanthine transport and was related to its lipid solubility in the same manner as observed for various substances whose permeation through the plasma membrane is believed to be non-mediated. Only the non-ionized form of 8-azaguanine (pKa = 6.6) permeated the cell membrane. Studies with wild type Novikoff cells showed that permeation into the cell was the main rate-determining step in the conversion of extracellular 8-azaguanine to intracellular aza-GTP and its incorporation into nucleic acids. In contrast, 6-mercaptopurine was rapidly transported into cells and phosphoribosylated; the main rate-determining step in its incorporation into nucleic acids was the further conversion of 6-mercaptopurine riboside 5'-monophosphate.

Avian and mammalian fibroblast cultures transformed by type C sarcoma viruses show a dramatic enhancement of the rate of hexose transport at the beginning of transformation which is quantitatively and qualitatively different from that seen by variation in culture conditions of nontransformed control cells. The identification of this change as being a transport alteration independent of total glucose metabolism has been shown by use of nonmetabolizable analogues, 2-deoxyglucose, 3-O-methylglucose, and L-glucose. Increased transport rates were not dependent on levels of hexokinase activity. Transport studies of 3-O-methylglucose confirmed these conclusions and further revealed an additional altered nature of hexose transport after transformation by sarcoma virus. 3-O-methylglucose was not only transported more rapidly in the transformed cells than in the parental nontransformed cells, but the sugar "infiltrated" into the transformed cells despite the inhibitory effect of cytochalasin B. This was not seen with control cells. The sarcoma cells were also able to transport L-glucose in contrast to lack of uptake by nontransformed cells. Under conditions in which cell toxicity was not a factor, 2-deoxyglucose and several other sugars present in culture media inhibited transformation by sarcoma viruses. These same sugars reduced the incidence of sarcomas produced by virus in vivo when administered daily to test animals. The transport changes also correlate well with the transformed state as found by other laboratories using temperature-sensitive mutants and revertant cell lines. Collectively these data suggest that manipulation of transport systems may prove useful for control of certain malignancies.

Techniques are described by which the transport of nutrients into mammalian cells in suspension can be measured at intervals of 1.5 seconds. By application of these techniques, the existence of a saturable (Km = 85 muM), non-concentrative, transport system for thymidine was demonstrated in Novikoff rat hepatoma cells depleted of ATP. At concentrations of thymidine less than the Km, this system operated at velocities sufficient to nearly completely equilibrate intra- and extra-cellular thymidine pools within 8 seconds. In phosphorylating cells, the transport system operated with similar rapidity, so that intracellular phosphorylation was rate-limiting for the incorporation of thymidine into nucleotides. Uptake of 3-O-methylglucose occurred at comparable velocities, attaining 90% of equilibrium between internal and external pools within 25 seconds. Uptake of cytosine by simple diffusion was 100 times slower.