The Clinical, Psychosocial, and Socioeconomic Concerns of Urban Youth Living With Diabetes

OBJECTIVE

Young people with chronic diseases face the challenge of moving from the pediatric to the adult health care environment, in addition to the normal hurdles of young adulthood. To most effectively help them through this process, we must first understand their perspective.

DESIGN

Qualitative study of the social and emotional impact of having diabetes.

SAMPLE

Young adults (n=23), aged 19-26, who had been living with diabetes for a median of 12 years (range 4-19) were contacted; all but one were from underserved ethnic minorities.

MEASUREMENTS

Semistructured telephone interviews were conducted, transcribed, and coded.

RESULTS

Having diabetes profoundly affected the life choices and expectations of these young people; their feelings and attitudes evolved over time. Financial and insurance concerns were key, because managing diabetes care on one's own as an adult was a major challenge. Most young people reported that family, friends, and coworkers were sources of support, but that disclosure of their diabetes was problematic.

CONCLUSIONS

Offering emotional and practical support to young adults coping with diabetes is key to ensuring adequate medical management as they move into the adult system and assume full responsibility for their health.

Evaluation of an internet diabetes self-management training program for adolescents and young adults

BACKGROUND

There are inadequate information and support resources available for adolescents and young adults with diabetes. This article describes the pilot phase of an Internet program to assist these individuals who are transitioning to adult-centered medical care.

METHODS

We developed an online program consisting of background information on diabetes, goal-setting exercises with individualized feedback, role-playing, group discussions, empowerment activities, and communication skills training designed to improve interactions with health professionals. We provided low-income participants enrolled in the study with recycled desktop computers and dial-up Internet service. They also received encouragement and computer use reminders from a diabetes educator. During a 6-month intervention period, we monitored participant utilization of the Internet program.

RESULTS

We recruited a convenience sample of 19 young adults with diabetes from the Chicago Childhood Diabetes Registry, as well as from two inner-city clinics. Participants accessed the program 4,445 times, with the discussion board receiving the greatest activity (2,256 total posted and read messages). Participants used the program most frequently at night, with an overall gradual decline in computer use over the 6-month period. To help maintain utilization, the diabetes educator placed a total of 439 telephone calls over 6 months (15-38 calls per participant).

CONCLUSIONS

The study demonstrated feasibility of using an Internet program to meet the informational and social needs of adolescents and young adults with diabetes. Participant involvement relied heavily upon reminders and encouragement from a diabetes educator and immediate family members.

Design and evaluation of a workplace intervention to promote organ donation

BACKGROUND

A number of efforts have been made to improve rates of deceased organ donation. However, few have been specifically designed for implementation in the workplace.

OBJECTIVES

To design and evaluate a workplace intervention to increase documentation of intention to be posthumous organ donors, communication of donation intention to families, and family members' documentation of their donation intentions.

METHODS

The study was a randomized controlled trial of corporate employees. Within each corporation, worksites were randomized to a control condition or 1 of 2 educational interventions. Measures included baseline and 1-month postintervention measures of stage of organ donation intention, stage of family notification, and family members' organ donation intention.

RESULTS

Across 12 corporations, 40 worksites with a total of 754 participants were randomized. At 1-month follow-up, 495 participants (66%) completed a posttreatment questionnaire. The percentage of participants who signed organ donor cards increased in the 2 intervention groups (29%, P < .001, and 31%, P < .002) but not in the control group (17%, P = .454). The percentage who discussed their donation intentions with family members increased significantly across all 3 arms (39%-47%, P < .001). The mean percentage of participants' family members who signed organ donor cards increased by 14% in the control group (P = .016) and by 17% in the 2 intervention groups (P < .001).

CONCLUSIONS

Educational interventions in the corporate workplace setting can be effective in increasing organ donation intention, family notification, and recruitment of family members as potential organ donors.

Preventing diabetes in the clinical setting

OBJECTIVE

Translating lessons from clinical trials on the prevention or delay of type 2 diabetes to populations in nonstudy settings remains a challenge. The purpose of this paper is to review, from the perspective of practicing clinicians, available evidence on lifestyle interventions or medication to prevent or delay the onset of type 2 diabetes.

DESIGN

A MEDLINE search identified 4 major diabetes prevention trials using lifestyle changes and 3 using prophylactic medications. We reviewed the study design, key components, and outcomes for each study, focusing on aspects of the interventions potentially adaptable to clinical settings.

RESULTS

The lifestyle intervention studies set modest goals for weight loss and physical activity. Individualized counseling helped participants work toward their own goals; behavioral contracting and self-monitoring were key features, and family and social context were emphasized. Study staff made vigorous follow-up efforts for subjects having less success. Actual weight loss by participants was modest; yet, the reduction in diabetes incidence was quite significant. Prophylactic medication also reduced diabetes risk; however, lifestyle changes were more effective and are recommended as first-line strategy. Cost-effectiveness analyses have shown both lifestyle and medication interventions to be beneficial, especially as they might be implemented in practice.

CONCLUSION

Strong evidence exists for the prevention or delay of type 2 diabetes through lifestyle changes. Components of these programs may be adaptable for use in clinical settings. This evidence supports broader implementation and increased reimbursement for provider services related to nutrition and physical activity to forestall morbidity from type 2 diabetes.

p47phox Associates With the Cytoskeleton Through Cortactin in Human Vascular Smooth Muscle Cells

OBJECTIVE

We tested the hypothesis that p47phox associates with the actin cytoskeleton, enabling site-directed activation of NAD(P)H oxidase, and assessed whether these actions influence reactive oxygen species (ROS) generation and signaling by angiotensin II (Ang II) in vascular smooth muscle cells (VSMCs) from human resistance and coronary arteries.

METHODS AND RESULTS

Electroporation of anti-p47phox antibody into VSMCs abrogated Ang II-mediated O2 generation, establishing the requirement for p47phox in this response. Immunfluorescence confocal microscopy demonstrated a cytosolic distribution of p47phox in basal conditions. After Ang II stimulation, p47phox rearranged in a linear fashion, colocalizing with F-actin. Co-immunoprecipitation studies confirmed an association between p47phox and actin and demonstrated an interaction with the actin-binding protein cortactin. Cytoskeletal disruption with cytochalasin prevented p47phox:actin interaction and attenuated ROS formation and p38MAP kinase and Akt phosphorylation by Ang II. Intracellular ROS generation in response to LY83583 (O2 generator) or exogenous H2O2 and Ang II-induced ERK1/2 activation were unaltered by cytochalasin.

CONCLUSIONS

The p47phox:actin interaction, through cortactin, plays an important role in Ang II-mediated site-directed assembly of functionally active NAD(P)H oxidase, ROS generation, and activation of redox-sensitive p38MAP kinase and Akt, but not ERK1/2. These findings demonstrate the importance of an intact actin-cytoskeleton in NAD(P)H oxidase regulation and redox signaling by Ang II in human VSMCs.

Activation-induced mobilization of secretory vesicles in bovine neutrophils

OBJECTIVE

To characterize mobilization of secretory granules in bovine neutrophils.

SAMPLE POPULATION

Neutrophils obtained from four 6- to 18-month-old Holstein cattle.

PROCEDURE

Mobilization of secretory granules in bovine neutrophils was determined by measuring changes in cell-surface alkaline phosphatase activity on cells treated with various inflammatory mediators. Subcellular distribution of the alkaline phosphatase activity was determined by analysis of bovine neutrophil homogenates fractionated on density gradients.

RESULTS

Alkaline phosphatase-containing secretory granules of bovine neutrophils were readily mobilized by a number of inflammatory agents, including platelet-activating factor, interleukin-8, tumor necrosis factor-alpha, lipopolysaccharide, leukotriene B4, and zymosan-activated plasma. In contrast, N-formyl-methionyl-leucyl-phenylalanine did not have a significant effect. Phorbol myristate acetate induced a biphasic response with up-regulation of cell-surface alkaline phosphatase at low doses and a return to baseline or even a reduction in cell-surface alkaline phosphatase at higher doses (> or = 10 ng/ml). Subcellular fractionation of bovine neutrophil homogenates revealed that alkaline phosphatase activity resided in light-density membrane vesicles (ie, location of secretory granules), which were distinct from specific, azurophil, and large granules.

CONCLUSIONS AND CLINICAL RELEVANCE

Bovine neutrophils respond to various inflammatory mediators by mobilizing alkaline phosphatase-containing secretory granules. This suggests that the process is an important early step in the host-defense response of bovine neutrophils.

A carbohydrate neoepitope that is up-regulated on human mononuclear leucocytes by neuraminidase treatment or by cellular activation

The expression of cell-surface antigens can delineate specific leucocyte developmental or functional stages. For example, certain membrane glycoproteins are expressed selectively on leucocyte subsets only after activation. Leucocyte activation can also induce changes in carbohydrate epitopes expressed on surface antigens. In the present studies, we report on a novel monoclonal immunoglobulin M antibody (mAb 13.22) that recognizes a unique carbohydrate epitope expressed on human leucocyte membrane proteins. Characterization of mAb 13.22 specificity by immunoblotting showed that it recognized proteins of MW approximately 95 000 and 150 000, including both CD18 and CD11b. The mAb 13.22 epitope was removed by N-glycosidase F but not by endoglycosidase H or fucosidase, demonstrating that it is an N-linked carbohydrate antigen. Interestingly, immunoblot staining was enhanced after neuraminidase treatment, suggesting that the antibody epitope might also be partially masked by sialic acid. In resting leucocytes, the mAb 13.22 antigen was expressed strongly on neutrophils, while dull staining was present on monocytes, and no lymphocyte staining was observed. In marked contrast, treatment of leucocytes with neuraminidase resulted in exposure of a mAb 13.22 neoepitope on a subset of lymphocytes (primarily T lymphocytes and natural killer cells) as well as up-regulated staining more than 18-fold on monocytes. Activation of lymphocytes in culture with phytohaemagglutinin or concanavalin A also unmasked the mAb 13.22 neoepitope on approximately 37% of the CD45RO+ lymphocytes. Furthermore, analysis of leucocytes collected from the synovial fluid of patients with rheumatoid arthritis showed that approximately 18% of the lymphocytes present expressed the mAb 13.22 neoepitope. Taken together, our results suggest that the mAb 13.22 carbohydrate neoepitope could represent a physiologically relevant marker that is up-regulated on leucocyte subsets during the inflammatory response.

Novel competitive inhibitor of NAD(P)H oxidase assembly attenuates vascular O(2)(-) and systolic blood pressure in mice

We previously reported enhanced expression of the p67(phox) and gp91(phox) components of NAD(P)H oxidase in angiotensin (Ang) II-induced hypertension, suggesting de novo assembly in response to Ang II. To examine the direct involvement of NAD(P)H oxidases in Ang II-induced O(2)(-) production, we designed a chimeric peptide that inhibits p47(phox) association with gp91(phox) in NAD(P)H oxidase (gp91ds-tat). This was achieved by linking a 9-amino acid peptide (aa) derived from HIV-coat protein (tat) to a 9-aa sequence of gp91(phox) (known to interact with p47(phox)). As a control, we constructed a chimera containing tat and a scrambled gp91 sequence (scramb-tat). We found that gp91ds-tat decreased O(2)(-) levels in aortic rings treated with Ang II (10 pmol/L) but had no effect on either the O(2)(-)-generating enzyme xanthine oxidase or potassium superoxide-generated O(2)(-). We infused vehicle, Ang II (0.75 mg. kg(-1). d(-1)), Ang II+gp91ds-tat (10 mg. kg(-1). d(-1)), or Ang II+scramb-tat intraperitoneally in C57Bl/6 mice and measured systolic blood pressure (SBP) on days 0, 3, 5, and 7 of infusion. SBP increased by day 3 in mice given Ang II and Ang II+scramb-tat but was significantly lower with Ang II+gp91-tat. On day 7, SBP was still significantly inhibited in mice given Ang II+gp91ds-tat, whereas Ang II-induced O(2)(-) production was inhibited throughout the aorta as detected by dihydroethidium staining, consistent with the ability of this inhibitor to block the various vascular NAD(P)H oxidase isoforms. These data support the hypothesis that inhibition of the interaction of p47(phox) and gp91(phox) (or its homologues) can block O(2)(-) production and attenuate blood pressure elevation in mice.

Role of NADPH Oxidase in the Vascular Hypertrophic and Oxidative Stress Response to Angiotensin II in Mice

Abstract —Oxygen-derived free radicals are involved in the vascular response to angiotensin II (Ang II), but the role of NADPH oxidase, its subunit proteins, and their vascular localization remain controversial. Our purpose was to address the role of NADPH oxidase in the blood pressure (BP), aortic hypertrophic, and oxidant responses to Ang II by taking advantage of knockout (KO) mice that are genetically deficient in gp91 phox , an NADPH oxidase subunit protein. The baseline BP was significantly lower in KO mice than in wild-type (WT) (92±2 [KO] versus 101±1 [WT] mm Hg, P <0.01), but infusion of Ang II for 6 days caused similar increases in BP in the 2 strains (33±4 [KO] versus 38±2 [WT] mm Hg, P >0.4). Ang II increased aortic superoxide anion production 2-fold in the aorta of WT mice but did not do so in KO mice. Aortic medial area increased in WT (0.12±0.02 to 0.17±0.02 mm 2 , P <0.05), but did not do so in KO mice (0.10±0.01 to 0.11±0.01 mm 2 , P >0.05). Histochemistry and polymerase chain reaction demonstrated gp91 phox localized in endothelium and adventitia of WT mice. Levels of reactive oxidant species as indicated by 3-nitrotyrosine immunoreactivity increased in these regions in WT but not in KO mouse aorta in response to Ang II. These results indicate an essential role in vivo of gp91 phox and NADPH oxidase–derived superoxide anion in the regulation of basal BP and a pressure-independent vascular hypertrophic and oxidant stress response to Ang II.

Training lay health educators to conduct a church-based weight-loss program for African American women

PURPOSE

Community-based lay health educators have been utilized in a range of settings and with a variety of health issues. However, little has been published about the specifics of training lay health educators to effectively deliver community-based programs. This paper describes the training used to prepare volunteer, church-based lay health educators to conduct a community-based weight-loss program, and the evaluation of that training.

METHODS

After recruitment through their respective churches, volunteer lay health educators were given structured training in how to conduct the PATHWAYS weight-loss program. Program sessions were observed to monitor program delivery, and participation rates and weight loss were evaluated.

RESULTS

The lay health educators were highly consistent in their delivery of the program content. Participant attendance was high and virtually all of the participants completed the program. Participant weight loss averaged 8.3 pounds, which correlated with session attendance.

CONCLUSIONS

Given training appropriate to the structure of the program and specific to the targeted health behavior, lay health educators can reliably and effectively administer even rather complex programs.

Host defense function in neutrophils from the American bison (Bison bison)

Selected host defense functions of neutrophils isolated from American bison (Bison bison) were characterized and compared with those of cattle (Bos taurus). Bison neutrophils had a robust chemotactic response to both IL-8 and LTB(4), with maximal responses occurring at 10(-7) M (IL-8) and 10(-8) M (LTB(4)). The magnitude of the chemotactic response to IL-8 was similar in bison and bovine neutrophils (except at 10(-7) M IL-8, where bison had a stronger response). In response to LTB(4), bison neutrophils had a much stronger chemotaxis at both 10(-8) and 10(-7) M than did bovine cells. Production of reactive oxygen species (ROS) in response to phorbol myristate acetate (PMA) and opsonized zymosan (OpZ) was similar between bison and bovine neutrophils. However, the production of ROS in bison neutrophils stimulated with OpZ was primarily intracellular, while extracellular release of ROS was evident in bovine neutrophils stimulated with OpZ. Like bovine neutrophils, bison neutrophils did not generate a respiratory burst in response to fMLF. Granules prepared from bison neutrophils had potent direct killing action on the Gram-negative bacteria Escherichia coli but failed to kill the Gram-positive bacteria Staphylococcus aureus and, at intermediate doses, actually had a permissive effect for this bacteria. Thus, bison neutrophils have potent host defense capabilities similar in quality to those of bovine neutrophils; however, unique differences are present, which may allow bison neutrophils to respond to the distinct immunological challenges that bison encounter.

Cloning and characterization of bovine low molecular weight GTPases (Rac1 and Rac2) and rho GDP-dissociation inhibitor 2 (D4-GDI)

GTPases of the Rho family play important roles in human leukocyte signal transduction pathways; however, little is known about the function of these proteins in bovine cells. In the present studies, we isolated molecular clones of bovine Rac1, Rac2, and the Rac/Rho GTPase regulatory protein D4-GDP dissociation inhibitor (D4-GDI) from a bovine bone marrow cDNA library. These clones contained complete open reading frames, encoding 192, 192, and 200 amino acids, respectively. Comparison of the bovine amino acid sequences with those of other species demonstrated a high degree of identity of these proteins across all species, suggesting that these proteins likely play conserved functional roles in bovine leukocyte signal transduction pathways. Comparative Western blotting of these proteins in human and bovine neutrophil cytosol demonstrated that Rac2 was the predominant Rac species and that D4-GDI was the predominant GDI species in bovine neutrophil cytosol. Despite the high degree of homology between human and bovine Rac2, some of the anti-peptide antibody probes prepared against human Rac2 failed to recognize the bovine homologue. We also showed by subcellular fractionation techniques that Rac2 is localized primarily to the cytosolic compartment of resting bovine neutrophils, but is translocated to the plasma membrane after stimulation with PMA. These findings suggest that Rac2 does play a role in bovine neutrophil activation. In addition, these data will be helpful in developing more specific probes for investigating the role of these proteins in bovine leukocyte signal transduction pathways and for studying various inflammatory diseases in cattle.

NADPH oxidase contributes directly to oxidative stress and apoptosis in nerve growth factor-deprived sympathetic neurons

Reactive oxygen species (ROS) are necessary for programmed cell death (PCD) in neurons, but the underlying ROS-producing enzymes have not been identified. NADPH oxidase produces ROS, although the expression of its five subunits are thought to be restricted largely to non-neuronal cells. Here, we show that NADPH oxidase subunits are present in neurons. Moreover, both an NADPH oxidase inhibitor, diphenyleneiodonium, and NAPDH oxidase genetic deficiency inhibit apoptosis in a classic model of PCD, i.e., NGF-deprived sympathetic neurons. Overall, these results indicate that NADPH oxidase is unexpectedly present in neurons and can contribute to neuronal apoptosis.

Cloning and expression of bovine p47-phox and p67-phox: comparison with the human and murine homologs

Neutrophils play an essential role in bovine cellular host defense, and compromised leukocyte function has been linked to the development of respiratory and mucosal infections. During the host defense process, neutrophils migrate into infected tissues where they become activated, resulting in the assembly of neutrophil membrane and cytosolic proteins to form a superoxide anion-generating complex known as the NADPH oxidase. Two of the essential cytosolic components of the NADPH oxidase are p47-phox and p67-phox. Currently, only the human and murine homologs of these proteins have been sequenced. Because of the important role neutrophils play in bovine host defense, we carried out studies to clone, sequence, and express bovine p47-phox and p67-phox. Using polymerase chain reaction (PCR) cloning techniques and a bovine bone marrow cDNA library, we have cloned both of these bovine NADPH oxidase cytosolic components. Comparison of the bovine sequences with those of the human and murine homologs showed that they were highly conserved, but also revealed important information regarding key structural features of p47-phox and p67-phox, including location of putative phosphorylation sites. Functional expression of bovine p47-phox and p67-phox showed that these proteins could substitute for the human proteins in reconstituting NADPH oxidase activity in a cell-free assay system, again demonstrating the high degree of conservation between human and bovine homologs. This study greatly contributes to our understanding of the potential structural/functional regions of p47-phox and p67-phox as well as providing information that can be used to study the role of neutrophils in bovine inflammatory diseases.

Cell-surface lactoferrin as a marker for degranulation of specific granules in bovine neutrophils

OBJECTIVE

To develop a rapid and accurate flow cytometric method for measuring degranulation of specific granules in bovine neutrophils.

SAMPLE POPULATION

Blood samples obtained from four 6- to 18-month-old Holstein cattle.

PROCEDURE

A monoclonal antibody (BL97) was generated against bovine lactoferrin and tested for applicability in ELISA, immunoprecipitation tests, immunofluorescence microscopy, and flow cytometric analyses. Using this antibody, cell-surface lactoferrin was measured concurrent with amount of secreted lactoferrin from bovine neutrophils activated with phorbol myristate acetate (PMA). Cell-surface lactoferrin also was measured on neutrophils in bovine whole blood stimulated with PMA, platelet-activating factor (PAF), N-formyl-methionyl-leucyl-phenylalanine (fMLF), and interleukin 8 (IL-8).

RESULTS

Antibody BL97 recognized bovine lactoferrin in ELISA and western immunoblots and was useful for immunoprecipitation testing, immunofluorescence microscopy, and flow cytometric analyses of bovine leukocytes. Neutrophils activated with PMA had parallel increases in content of secreted lactoferrin (measured by ELISA) and cell-surface lactoferrin (measured by flow cytometry) with increasing PMA concentrations. In addition, fluorescein-conjugated BL97 antibody detected increases in cell-surface lactoferrin on neutrophils in bovine whole blood after activation with PMA, PAF, and IL-8. In contrast, increases in cell-surface lactoferrin were not detected on bovine neutrophils treated with fMLF.

CONCLUSION AND CLINICAL RELEVANCE

Measurement of cell-surface lactoferrin on bovine neutrophils by flow cytometry is a valid and rapid method for assessment of release of lactoferrin from specific granules in these cells and represents a means to rapidly measure neutrophil activation. This technique allows for investigation of mechanisms of neutrophil modification in isolated cells as well as in whole blood.

Selective recruitment of T-cell subsets to the udder during staphylococcal and streptococcal mastitis: analysis of lymphocyte subsets and adhesion molecule expression

During bacterial infection of the bovine mammary gland, large numbers of leukocytes migrate into the udder, resulting in the establishment of a host response against the pathogen. Currently, the specific leukocyte populations mediating this immune response are not well defined. In the studies described here, we analyzed blood and milk from healthy cows and cows with naturally occurring mastitis to determine if distinct alphabeta and gammadelta T-lymphocyte subsets were involved in the response of the udder to a mastitis pathogen and if the type of mastitis pathogen influenced the subset composition of these responding leukocytes. Although blood samples from cows with confirmed staphylococcal and streptococcal mastitis were characterized by increased numbers of gammadelta T cells, the most dramatic changes in leukocyte distributions occurred in milk samples from these cows, with a 75% increase in alphabeta T-cell levels and a 100% increase in gammadelta T-cell levels relative to the levels in milk samples from healthy animals. Interestingly, the increase in alphabeta T-cell numbers observed in milk from cows with staphylococcal mastitis was primarily due to increased numbers of CD4(+) T cells, while the increase in alphabeta T-cell numbers observed in cows with streptococcal mastitis was due to a parallel increase in both CD4(+) and CD8(+) T-cell numbers. The increased numbers of gammadelta T cells in milk from cows with staphylococcal and streptococcal mastitis were due to a selective recruitment of a distinct gammadelta T-cell subset (GD3.1(+)), while no change in the numbers of GD197(+) gammadelta T cells was observed. We also analyzed adhesion protein expression on blood and milk leukocytes and found that, in comparison to the situation for healthy cows, L-selectin was down-regulated and CD18 was up-regulated on leukocytes from cows with mastitis. Thus, shedding of L-selectin and up-regulation of CD18 by neutrophils may provide a sensitive indicator of early inflammatory responses during bovine mastitis. Overall, these studies suggest that distinct alphabeta and gammadelta T-cell subsets are involved in the host defense of the udder against mastitis infection and that selective recruitment of these T-cell subsets depends on the infectious agent involved.

Analysis of surface antigen expression and host defense function in leukocytes from calves heterozygous or homozygous for bovine leukocyte adhesion deficiency

OBJECTIVE

To analyze surface antigen expression and functional responses of leukocytes from calves heterozygous and homozygous for bovine leukocyte adhesion deficiency (BLAD).

ANIMALS

8 clinically normal calves, 4 calves heterozygous for BLAD, and 4 calves homozygous for BLAD.

PROCEDURE

Surface antigen expression was examined by flow cytometric analysis of leukocytes stained with monoclonal antibodies. Neutrophil function analyses included phagocytosis and killing of Candida albicans and measurement of respiratory burst activity using cytochrome c and dihydrorhodamine 123 assays. Differential leukocyte counts also were performed.

RESULTS

Leukocytes from heterozygous calves were similar to those of clinically normal calves with respect to surface antigen expression, C albicans phagocytosis and killing, and respiratory burst activity. In contrast, neutrophils from calves homozygous for BLAD had significantly reduced phagocytic and yeast-killing capacity but had higher respiratory burst activity than cells from clinically normal or heterozygous calves. Homozygous calves also had extreme neutrophilia and significantly more immature neutrophils.

CONCLUSIONS

The heterozygous BLAD genotype does not cause detectable functional differences in leukocytes, compared with those of clinically normal calves. In contrast, leukocytes from homozygous calves seem to upregulate alternative host defense capabilities (eg, respiratory burst activity) to partially compensate for the lack of typical adherence-dependent host defense functions.

Isolation of bovine neutrophils with biomagnetic beads: comparison with standard Percoll density gradient isolation methods

A prerequisite for studies on bovine neutrophils is a reliable method of neutrophil isolation from blood to obtain highly purified cell populations that are functionally active. Since current techniques of neutrophil isolation fall short of these requirements, we have developed a newer and more effective technique for isolation of bovine neutrophils that utilizes biomagnetic beads coated with a monoclonal antibody that recognizes an abundant surface antigen on bovine neutrophils to purify these cells. Comparison of the purity and viability of bovine neutrophils isolated by a conventional method (continuous Percoll density gradient) with this new method showed that neutrophils isolated with biomagnetic beads were higher in purity and had an increased yield. In addition, cells isolated with biomagnetic beads demonstrated normal or even improved function in assays of chemotaxis, phagocytosis, degranulation, and respiratory burst activity. Finally, bovine neutrophils isolated using this method showed an overall lower level of spontaneous apoptosis, which correlates well with the high level of viability observed in the purified cell preparations. Thus, this method represents a significant advance over current methods for isolating bovine neutrophils and would be widely applicable to labs studying the biochemistry and signal transduction pathways in these cells.

Paracrine role of adventitial superoxide anion in mediating spontaneous tone of the isolated rat aorta in angiotensin II-induced hypertension

The relationship between vascular generation of superoxide anion and spontaneous tone observed in the isolated aorta was studied in hypertensive rats infused with angiotensin II. Aortic rings from hypertensive, but not from sham-operated rats, demonstrated oscillatory spontaneous tone that represented 52+/-5.6% of the maximal contraction to KCl. Spontaneous tone was prevented by calcium-free buffer or by blocking calcium influx through L-type calcium channels with nifedipine. The production of superoxide anion measured by lucigenin chemiluminescence was up to 15-fold higher than in sham-operated rat aorta. The adventitial site of production of superoxide anion was suggested by the fact that lucigenin chemiluminescence was 5.5-fold higher from the adventitia than from the intima. This was confirmed histochemically by demonstrating that the adventitia was the site of reduction of nitroblue tetrazolium as well as immunohistochemical staining of NAD(P)H oxidase subunit proteins. A causal link between superoxide anion production by NAD(P)H oxidase and the spontaneous tone is suggested by the fact that superoxide dismutase or the inhibitor of NAD(P)H oxidase, diphenylene iodonium, decreased both superoxide anion production and spontaneous tone. L-NAME or removal of the endothelium from the aorta had no significant effect on superoxide anion levels or spontaneous tone. However, although superoxide dismutase decreased superoxide anion levels in the presence of L-NAME or in endothelium-denuded rings, it no longer inhibited the tone. This suggests that the effect on tone of superoxide anion originating in the adventitia is mediated by inactivating endothelium-derived nitric oxide, which promotes smooth muscle calcium influx and spontaneous tone. The adventitia is not a passive bystander during the development of hypertension, but rather it may have an important role in the regulation of smooth muscle tone.

Inhibition of GTP binding to Rac2 by peroxynitrite: potential role for tyrosine modification

Peroxynitrite is a potent oxidant generated by the reaction of nitric oxide (*NO) and superoxide anion (O2*-), and both can be produced in inflammatory tissues. In the present studies, we analyzed the effects of peroxynitrite treatment on the GTP-binding activity of Rac2, a low molecular weight GTP-binding protein important in regulating a number of cellular functions. Using a fluorescent analog of GTP (methylanthraniloyl guanosine triphosphate or mant-GTP) as a reporter group, we found that treatment of Rac2 with peroxynitrite inhibited the binding of mant-GTP to Rac2 in a dose-dependent manner. Peroxynitrite was also able to react directly with free mant-GTP, resulting in a significant decrease in mant-GTP fluorescence; however, the mechanism of peroxynitrite-mediated damage to mant-GTP was different than with Rac2. In the case of mant-GTP, protection from peroxynitrite-mediated oxidation was observed in the presence of the free radical scavengers, mannitol and DMTU. In contrast, DMTU was unable to prevent peroxynitrite-mediated inhibition of mant-GTP binding to Rac2. Instead, our data demonstrates a role for peroxynitrite-mediated tyrosine modification in the inhibition of mant-GTP binding to Rac2, and we were able to demonstrate the formation of a significant level of nitrotyrosine formation in Rac2 exposed to peroxynitrite. Thus, our studies support the premise that oxidative modification of key cellular proteins, such as Rac2, plays an important role in the cytotoxic effects observed for peroxynitrite and other reactive oxidants.

Interview strategies commonly used by pediatricians

OBJECTIVES

To describe the pediatric interview as it is conducted in different practice settings and with children ranging in age from infancy to adolescence, and to identify pediatric history-taking strategies that varied across age groups.

PARTICIPANTS AND METHODS

A self-administered survey was designed and mailed to a group of pediatricians in the Chicago metropolitan area to assess commonly used strategies in the pediatric interview across varied patient ages and settings. The pediatricians sampled varied by geographic location as well as by practice setting.

RESULTS

Results of the survey indicated that pediatricians use common strategies for establishing rapport, calming the disruptive child, and obtaining information from the child within particular age groups, but vary these strategies as the child matures.

CONCLUSIONS

The findings substantiate the influence of the developmental stage of the child on interview strategies used by pediatricians. Implications pertaining to development of a standardized teaching curriculum for the pediatric interview are also discussed.

Modulation of endotoxin- and enterotoxin-induced cytokine release by in vivo treatment with beta-(1,6)-branched beta-(1,3)-glucan

Leukocytes activated by endotoxin or enterotoxins release proinflammatory cytokines, thereby contributing to the cascade of events leading to septic shock. In the present studies, we analyzed the effects of in vivo administration of a soluble immunomodulator, beta-(1,6)-branched beta-(1,3)-glucan (soluble beta-glucan), on toxin-stimulated cytokine production in monocytes and lymphocytes isolated from treated mice. In vitro stimulation of lymphocytes isolated from soluble beta-glucan-treated mice with lipopolysaccharide (LPS) resulted in enhanced production of interleukin-6 (IL-6) and suppressed production of tumor necrosis factor alpha (TNF-alpha), while stimulation of these cells with staphylococcal enterotoxin B (SEB) or toxic shock syndrome toxin 1 (TSST-1) resulted in enhanced production of gamma interferon (IFN-gamma) and suppressed production of IL-2 and TNF-alpha compared to that in cells isolated from untreated mice. In vitro stimulation of monocytes isolated from soluble beta-glucan-treated mice with LPS also resulted in suppressed TNF-alpha production, while stimulation of these cells with SEB or TSST-1 resulted in suppressed IL-6 and TNF-alpha production compared to that in cells isolated from untreated mice. Thus, the overall cytokine pattern of leukocytes from soluble beta-glucan-treated mice reflects suppressed production of proinflammatory cytokines, especially TNF-alpha. Taken together, our results suggest that treatment with soluble beta-glucan can modulate the induction cytokines during sepsis, resulting in an overall decrease in host mortality.

Priming of human neutrophils by peroxynitrite: potential role in enhancement of the local inflammatory response

Peroxynitrite is a potent oxidant generated from the reaction of nitric oxide (NO) and superoxide anion (O2-), both of which can be produced in inflammatory tissues. In these studies, we analyzed what direct effect peroxynitrite had on neutrophil (PMN) function. We found that peroxynitrite was an effective priming agent for PMNs, as demonstrated by enhanced O2- production on subsequent activation with low doses of PMA or N-formyl-methionine-leucine-phenylalanine (fMLF), changes in the expression of PMN surface markers (L-selectin, Mac-1, flavocytochrome b, and fMLF receptor), and increased intracellular calcium levels. Analysis of the mechanism of PMN priming by peroxynitrite demonstrated that peroxynitrite resulted in minimal oxidation of protein sulfhydryl groups and subsequent protein cross-linking. In contrast, treatment of PMNs with peroxynitrite resulted in significant nitration of tyrosine residues on neutrophil proteins. In addition, inhibition of tyrosine nitration with a pyrrolopyrimidine antioxidant blocked the majority of peroxynitrite-induced priming effects, further suggesting that PMN priming was mediated primarily by nitration of tyrosine residues on PMN proteins. The ability of peroxynitrite to serve as an effective priming agent for PMNs at sites of inflammation may play a key role in modulating the host-defense process.