Biomedical subjects

L A Jackson

Publications and source records attributed to L A Jackson.

At least 19 recordsLinked to original sources

PubMed2007

The effects of salivary gland extracts from Boophilus microplus ticks on mitogen-stimulated bovine lymphocytes.

The effect of salivary gland extract (SGE) from the tick Boophilus microplus was examined in mitogen-stimulated lymphocytes in vitro. SGE was added to lymphocytes of seven cattle together with the mitogens concanavalin A (ConA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). Semi-purified B cells from another seven cattle were stimulated with the mitogen lipopolysaccharide (LPS). PHA and ConA stimulated proliferation of lymphocytes to the same extent, but the inhibition due to SGE of Boophilus microplus on the proliferative response stimulated by PHA (39.0% +/- 9.3%) was less than the inhibition of proliferative response stimulated by ConA (75.4% +/- 6.9%). In contrast, SGE of B. microplus stimulated the proliferation of B cells in the presence of LPS in a dose-dependent manner. Enhanced stimulation of B cells by SGE at >4 microg in culture was greater than twice that observed when B cells were stimulated by LPS alone. SGE does not have a direct suppressive effect on bovine B cell proliferation; however, in vivo the effectiveness of B cell responses might be influenced by other immune factors, such as cytokine profiles.

Animals↗

PubMed2004

A comparison of the immunosuppressive effects of salivary gland extracts from two laboratory strains of Boophilus microplus.

This study addresses three questions related to the immune response of cattle to tick salivary gland extracts. Firstly, is there a difference in the inhibition of proliferation of Concanavalin A (ConA) stimulated bovine lymphocytes induced by salivary gland extracts of the N and Y strains of Boophilus microplus? Second, is there a difference in the development rate of the Y and N tick strains? Third, does the host affect the inhibitory effect of salivary gland extract on the proliferation of ConA stimulated lymphocytes from the two tick strains? Salivary gland extract of the Y strain inhibited in vitro proliferation of lymphocytes stimulated by ConA significantly more than that of the N strain, when each strain was raised on different animals. A difference in the development rate was observed between the tick strains when raised on the same animal, with female ticks of the Y strain developing faster and reaching a greater fully engorged weight than ticks of the N strain. The difference in their rate of development did not appear to contribute to a difference in inhibitory effects of the salivary gland extracts and there was no difference between the inhibitory effects of salivary gland extracts from both strains. However, when Y strain ticks were raised on different animals, there was a significant difference in the inhibition of lymphocyte proliferation between the two salivary gland extracts. Therefore, it was concluded that there is no difference between the inhibitory effects of the two tick strains and that the host has an influence on salivary gland extract composition of B. microplus and its inhibitive properties.

Animals↗

PubMed2001

Safety and immunogenicity of varying dosages of trivalent inactivated influenza vaccine administered by needle-free jet injectors.

To evaluate the perceived pain, other adverse events, and immunogenicity of influenza virus vaccine administered by needle-free jet injector (JI) compared with that of vaccine administered by needle and syringe (N&S), we randomly assigned 304 healthy young adults to receive one of three dosages (0.5, 0.3, or 0.2 ml) of the 1998-1999 season vaccine administered by either of two JI devices or by N&S. In multivariate analysis, female gender and JI administration were associated with higher levels of pain reported at the time of vaccination as well as with the occurrence of local injection site reactions following vaccination. Immune response did not vary significantly by dosage but administration by one JI device was associated with higher post-vaccination H1N1 antibody titers.

Adult↗

PubMed2001

Standardizing Chlamydia pneumoniae assays: recommendations from the Centers for Disease Control and Prevention (USA) and the Laboratory Centre for Disease Control (Canada).

Chlamydia pneumoniae has been associated with atherosclerosis and several other chronic diseases, but reports from different laboratories are highly variable and "gold standards" are lacking, which has led to calls for more standardized approaches to diagnostic testing. Using leading researchers in the field, we reviewed the available approaches to serological testing, culture, DNA amplification, and tissue diagnostics to make specific recommendations. With regard to serological testing, only use of microimmunofluorescence is recommended, standardized definitions for "acute infection" and "past exposure" are proposed, and the use of single immunoglobulin (Ig) G titers for determining acute infection and IgA for determining chronic infection are discouraged. Confirmation of a positive culture result requires propagation of the isolate or confirmation by use of polymerase chain reaction (PCR). Four of 18 PCR assays described in published reports met the proposed validation criteria. More consistent use of control antibodies and tissues and improvement in skill at identifying staining artifacts are necessary to avoid false-positive results of immunohistochemical staining. These standards should be applied in future investigations and periodically modified as indicated.

Bacteriological Techniques↗

PubMed2001

Diphtheria antitoxin levels among children primed with a diphtheria and tetanus toxoids and acellular pertussis vaccine lot with a subpotent diphtheria toxoid component.

One lot of a nationally distributed diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine was recalled in January 1999 because of a subpotent diphtheria toxoid component. To evaluate vaccine immunogenicity, children who had received the recalled lot for at least 2 of the 3 doses of their primary series were identified. Diphtheria antitoxin (DAT) levels were then prospectively assessed before and after dose 4 of (fully potent) DTaP vaccine. Of the 105 children evaluated, 84% had prevaccination DAT levels <0.10 IU/mL, which is the level generally accepted as protective. DAT levels rose a mean of 92-fold after dose 4; 100% of subjects had DAT levels >or=0.10 IU/mL, and 69% had DAT levels >or=1.0 IU/mL. These results indicate that diphtheria potency testing can identify vaccine that is less immunogenic when administered during the primary series. The booster response to dose 4, although reduced, was sufficient to confer adequate protection in the interval before receipt of the fifth dose of DTaP.

Antibodies, Bacterial↗

PubMed2001

Theileria annulata: attenuation of a schizont-infected cell line by prolonged in vitro culture is not caused by the preferential growth of particular host cell types.

Flow cytometry and monoclonal antibodies to bovine leucocyte surface antigens were used to identify the types of host cells that the sporozoites of Theileria annulata infect in cattle, to determine whether virulent schizont-infected cell lines (lines) differed phenotypically from avirulent lines, and to establish whether attenuation in vitro was accompanied by the preferential growth of particular host cell types. The surface antigens of four pairs of T. annulata (Ta) (Hisar) lines derived ex vivo and in vitro, including the virulent ex vivo-derived Ta Hisar S45 line, were consistent with a myeloid origin for all lines, irrespective of their derivation. The profiles of lines derived from cattle inoculated with a virulent line showed that the schizonts liberated from inoculated cells had transferred to myeloid cells. A number of other lines infected with different stocks of T. annulata expressed myeloid markers; a single line expressed CD21, a B cell marker. During prolonged in vitro culture, the parasites in the ex vivo (virulent)- and in vitro (avirulent)-derived Ta Hisar S45 myeloid lines became clonal, as defined by glucose phosphate isomerase (GPI) polymorphism, and the virulent line became attenuated. The two lines retained phenotypic profiles indicative of a myeloid origin but coexpressed some lymphoid antigens (CD2, CD4, CD8), although not CD3. Cloned schizont-infected lines, representing the three parasite GPI isotypes which constituted the virulent line, expressed similar patterns of myeloid and lymphoid markers to the virulent parent line. Some schizont-infected clones failed to establish as lines during the early weeks of culture because the cells died as the parasites differentiated into merozoites at 37 degrees C, the temperature at which schizont-infected cells normally grow exponentially. These results provided no evidence that prolonged culture induces preferential growth or loss of particular host cell types. However, a number of the alterations in host cell surface antigens induced by prolonged culture were shown to be linked to permanent changes in the parasite genome.

Animals↗

PubMed2001

Babesia bovis: culture of laboratory-adapted parasite lines and clinical isolates in a chemically defined medium.

Babesiosis caused by Babesia spp. is a disease of both veterinary and human importance. Here, we describe a method to continuously culture laboratory lines and field isolates of Babesia bovis in vitro in a chemically defined medium using (ALBU)MAX II as an alternative to bovine serum. Further, we have successfully cultured parasite isolates directly from cattle that failed to grow in traditional serum-containing medium. Variation of atmospheric gas composition and culture volumes to determine optimal growth conditions revealed that a 600-microl culture in an atmosphere comprising 5% O(2), 5% CO(2), and 90% N(2) achieved a significantly higher percentage of parasitized red blood cells than any other combination tested. The process could be scaled up to reliably produce large volumes of parasites. Supplementation of the culture medium with hypoxanthine further improved parasite growth. B. bovis cultured in this way could be the basis of an alternative, safer vaccine and a reliable source of parasites and exoantigens for parasitological research.

Animals↗

PubMed2001

Elevated anti-parasitic activity in peripheral blood monocytes and neutrophils of cattle infected with Babesia bovis.

The innate immune response to bovine Babesia bovis infection in vivo has not previously been established. We used assays measuring phagocytosis and oxidative burst to investigate the immune response because they are indicative of the innate antimicrobial capacity of monocytes and neutrophils. Monocyte and neutrophil phagocytosis is thought to be non-specific in nature and so the phagocytosis of either opsonised Zymosan or Escherichia coli was used to indicate the non-specific phagocytic capacity of monocytes and neutrophils ex vivo. The kinetics of both phagocytic and oxidative burst activity in monocytes and neutrophils were followed twice weekly from pre-inoculation (day 0) through to 31 days after inoculation. Peripheral blood monocytes were found to display a pronounced oxidative burst, but a suppressed capacity to phagocytose during a primary infection. On the other hand, neutrophils exhibited an increased phagocytic capacity and reduced oxidative activity during a primary infection. These findings identified considerable antimicrobial activity evident in peripheral blood monocytes and neutrophils from cattle exposed to B. bovis as a primary exposure. This elevated antimicrobial activity was coincident with the time that parasite numbers peaked in the circulation and occurred prior to parasite clearance. These results suggest that peripheral blood monocytes and neutrophils are active mediators in the innate immune response to a primary B. bovis.

Animals↗

PubMed2001

Effects of affect, stereotype consistency, and valence of behavior on causal attributions.

The authors examined 3 hypotheses about the effects of 2 positive and 2 negative affects on causal attributions. On the basis of cognitive appraisal theories of emotion, they predicted that the grateful and angry participants would attribute causality for like-valenced behaviors to the target more strongly than would the happy and sad participants, respectively. Following an affect-induction procedure, 229 Anglo-American participants read a description of an African American target whose behavior was stereotype consistent or stereotype inconsistent and positive or negative in valence. As predicted, when the behavior was negative, the angry participants attributed it more strongly to the target than did the sad participants. When the behavior was positive, the grateful participants attributed it more strongly to the target than did the happy participants. The importance of distinguishing among affects and considering their multidimensional nature in predicting effects on social judgments is emphasized.

Adult↗

PubMed2000

Frequency of serological evidence of Bordetella infections and mixed infections with other respiratory pathogens in university students with cough illnesses.

Banked acute-phase and convalescent-phase serum samples from a previous study of respiratory illness in university students were examined for significant (>/=2-fold) increases in ELISA titers of IgA and IgG antibody to Bordetella pertussis filamentous hemagglutinin, pertactin, and fimbriae-2 and >/=4-fold titer increases to agglutinogens by agglutination. ELISA titers of antibody to pertussis toxin could not be determined because of technical problems. Chlamydia pneumoniae infections were diagnosed by culture or by a >/=4-fold increase in immunofluorescence assay titer or a single high titer (>/=512). Mycoplasma pneumoniae, influenza A and B, adenovirus, and respiratory syncytial virus infections were diagnosed by >/=4-fold increases in complement fixation titer or a single high titer (>/=64). There were 319 subjects with cough of >/=5 days' duration, and of these, 47 (15%) had significant increases in antibody to B. pertussis antigens; 26 (8%) had significant increases to fimbriae-2 or agglutinogens, indicative of B. pertussis infection, and 2 (1%) had evidence of non-B. pertussis bordetella infections. Seventeen (36%) had evidence of mixed infections or cross-reacting antibodies (influenza B infections, 5; adenovirus infections, 4; influenza A infections, 3; C. pneumoniae infections, 3; and M. pneumoniae infections, 2). Our findings suggest that bordetella infections are common in young adults with cough illnesses (incidence, 9%), and a surprising number of these are mixed infections with other respiratory pathogens.

Adenovirus Infections, Human↗

PubMed2000

Prolonged afebrile nonproductive cough illnesses in American soldiers in Korea: a serological search for causation.

A serological study was undertaken to investigate infections in active-duty United States soldiers with illnesses characterized by prolonged, afebrile, nonproductive coughs. Fifty-four soldiers were enrolled with such illness of >/=2 weeks' duration (case patients) along with 55 well soldiers (control subjects). Serum samples were tested for IgG and IgA antibody to 3 Bordetella pertussis antigens, pertussis agglutinins, IgM antibodies to Mycoplasma pneumoniae, IgM and IgG antibodies to Chlamydia pneumoniae, and IgM antibody to adenoviruses. Forty-six case patients (85%) had evidence of recent infection with Bordetella species, M. pneumoniae, or C. pneumoniae, and many had evidence of mixed infections; there were 27 Bordetella species, 20 C. pneumoniae, and 33 M. pneumoniae recent infections. Fifteen case patients had high titers of IgG or IgA to B. pertussis filamentous hemagglutinin without high titers of antibodies to other B. pertussis antigens, which suggested the presence of cross-reacting antibodies to M. pneumoniae and perhaps C. pneumoniae or unidentified infectious agent or agents. Since illnesses due to Bordetella species, M. pneumoniae, and C. pneumoniae can all be treated with macrolide antibiotics and B. pertussis illness can be prevented by immunization, and since military readiness was affected in 63% of the cases, it seems important to conduct further studies in military populations.

Adenovirus Infections, Human↗

PubMed2000

Past use of erythromycin, tetracycline, or doxycycline is not associated with risk of first myocardial infarction.

A population-based case-control study of patients enrolled at Group Health Cooperative of Puget Sound was conducted to evaluate whether past use of antibiotics active against Chlamydia pneumoniae is associated with a decrease in the risk of first myocardial infarction (MI). Cases with incident fatal and nonfatal MI from mid-1986 through 1995 (n=1796) were compared with randomly sampled controls frequency-matched to cases for age, sex, and year (n=4882). Use of erythromycin, tetracycline, or doxycycline during the previous 5 years was not associated with an alteration in the risk of first MI. In an adjusted logistic regression model, the odds ratios and 95% confidence intervals for categories of cumulative duration of therapy with any of the three agents combined for 0, 1-14, 15-28, and >/=29 days were 1.0 (reference), 0.93 (0.81-1.07), 0.99 (0.81-1.20), and 1.03 (0.84-1.26), respectively. These results suggest little or no association between past use of erythromycin or tetracycline antibiotics and the risk of first MI among this population.

Aged↗

PubMed2000

Specificity of detection of Chlamydia pneumoniae in cardiovascular atheroma.

Chlamydia pneumoniae is commonly detected in atherosclerotic plaque but the frequency of detection in non-cardiovascular (CV) tissues has not been well determined. In this study, archival autopsy tissue specimens from both CV and non-CV sites from 38 patients were tested by polymerase chain reaction and immunocytochemistry to detect C. pneumoniae. In addition, 33 surgical granuloma biopsy specimens were also tested. C. pneumoniae was detected most frequently in coronary artery tissue (34%) but was also detected in specimens from lung (13%), liver (10%), spleen (5%), bone marrow (10%), and lymph node (8%). The organism was detected in 3 of 33 granuloma specimens. These findings suggest that C. pneumoniae demonstrates a tropism for CV tissues and is either not widely distributed to non-CV tissues or does not persist chronically in those tissues after initial infection.

Arteries↗

PubMed2000

Description and status of the azithromycin and coronary events study (ACES).

The Azithromycin and Coronary Events Study is a randomized, double-blind, placebo controlled trial of azithromycin among adults with stable coronary artery disease. The study is based on the hypothesis that infection with Chlamydia pneumoniae may be causally associated with cardiovascular disease and therefore that treatment directed against this organism may reduce the risk of subsequent coronary events. Participants randomized to treatment will receive 600 mg of azithromycin orally once a week for 1 year and will be followed a mean of 4 years for the composite primary outcome of coronary heart disease death, nonfatal myocardial infarction, hospitalization for unstable angina, and coronary revascularization. Secondary objectives include those related to a better understanding of the relationship between antibody titer and inflammatory markers with treatment status and outcome; therefore, all participants will have blood specimens obtained at enrollment and a random 25% will have additional specimens collected periodically during follow-up.

Adult↗

PubMed2000

The Vaccine Safety Datalink: immunization research in health maintenance organizations in the USA.

The Vaccine Safety Datalink is a collaborative project involving the National Immunization Program of the Centers for Disease Control and Prevention and several large health maintenance organizations in the USA. The project began in 1990 with the primary purpose of rigorously evaluating concerns about the safety of vaccines. Computerized data on vaccination, medical outcome (e.g. outpatient visits, emergency room visits, hospitalizations, and deaths) and covariates (e.g. birth certificates, census data) are prospectively collected and linked under joint protocol at multiple health maintenance organizations for analysis. Approximately 6 million persons (2% of the population of the USA) are now members of health maintenance organizations participating in the Vaccine Safety Datalink, which has proved to be a valuable resource providing important information on a number of vaccine safety issues. The databases and infrastructure created for the Vaccine Safety Datalink have also provided opportunities to address vaccination coverage, cost-effectiveness and other matters connected with immunization as well as matters outside this field.

Centers for Disease Control and Prevention, U.S.↗

PubMed2000

Association of Chlamydia pneumoniae immunoglobulin A seropositivity and risk of lung cancer.

Chlamydia pneumoniae is a common respiratory pathogen that has also been associated with risk for chronic diseases, including atherosclerotic cardiovascular disease. Two recent studies have reported an association between serological evidence of past infection with the organism and lung cancer. To further evaluate this association, we conducted a case-control study among a subgroup of white male smokers identified for a population-based case-control study of lung cancer in western Washington between 1993 and 1995. Serum specimens obtained at study enrollment from 143 cases and 147 controls were tested for C. pneumoniae IgG, IgM, and IgA antibodies. In multivariate analysis controlling for smoking variables and educational status, IgA antibody titer 216 was independently associated with risk of lung cancer among subjects <60 years of age [odds ratio (OR), 2.67; 95% confidence interval (CI), 1.21-5.89] but not among older subjects (OR, 0.69; 95% CI, 0.34-1.43). Among subjects <60 years of age, there was suggestive evidence of a stronger association among current smokers (OR 4.31; 95% CI, 1.36-13.68) than former smokers (OR 1.50; 95% CI, 0.48-4.75; P for interaction term, 0.26). Additional studies, including prospective serological evaluations, are needed to further assess the possible significance of this association.

Aged↗

PubMed2000

The effect of additional shots on the vaccine administration process: results of a time-motion study in 2 settings.

CONTEXT: The introduction of combination vaccines to the pediatric regimen offers the possibility of reducing the number of injections required to reach full vaccination status. Fewer injections benefit the patient/child and the parent/caregiver, and the healthcare provider may benefit from savings in personnel time associated with vaccine administration. To date, however, these savings have not been quantified. OBJECTIVE: To study the vaccine administration process in a managed care environment. STUDY DESIGN: We studied 2 settings in which vaccinations were administered: (1) a devoted injection room and (2) the examination room as part of the well-child examination. For each setting, we documented the vaccine administration process, identified vaccine-related activities, and quantified the time savings in each activity by reductions in the number of shots. PATIENTS AND METHODS: For vaccine recipients younger than 2 years, time-motion data on vaccine-related activities in 2 managed care settings were collected by a professional industrial engineering consultant. Activity time data by the number of shots administered were analyzed using linear regression adjusting for patient age. RESULTS: We observed 276 vaccination visits (137 in an examination room, and 139 in an injection room). Total nurse time associated with vaccine administration decreased by 2.4 and 1.7 minutes per shot eliminated in the examination room setting (P = .006) and in the injection room setting (P < .001), respectively. Significant time savings were realized for activities associated with vaccine preparation, vaccine injection, and administrative duties. In addition, infant crying time decreased by 1.0 and 0.4 minutes per shot eliminated in the examination room and injection room settings, respectively (P < or = .001 for both). CONCLUSIONS: Significant reductions in vaccine administration time could be achieved by eliminating injections during a well-child regimen.

Child Health Services↗

PubMed1999

Effectiveness of live, attenuated intranasal influenza virus vaccine in healthy, working adults: a randomized controlled trial.

CONTEXT: Influenza virus is a major cause of illness, disruption to daily life, and increased use of health care in all age groups. OBJECTIVE: To assess the safety and effectiveness of intranasally administered trivalent, live, attenuated influenza virus (LAIV) vaccine for reducing illness, absenteeism, and health care use among healthy, working adults. DESIGN: Randomized, double-blind, placebo-controlled trial conducted from September 1997 through March 1998. SETTING: Thirteen centers across the United States. PARTICIPANTS: A total of 4561 healthy, working adults aged 18 to 64 years recruited through health insurance plans, at work sites, and from the general population. INTERVENTION: Participants were randomized 2:1 to receive intranasally administered trivalent LAIV vaccine (n = 3041) or placebo (n = 1520) in the fall of 1997. MAIN OUTCOME MEASURES: Episodes of febrile illness, severe febrile illness, febrile upper respiratory tract illness, work loss, and health care use during the peak and total influenza outbreak periods, and adverse events. RESULTS: Recipients of LAIV vaccine were as likely to experience 1 or more febrile illnesses as placebo recipients during peak outbreak periods (13.2% for vaccine vs 14.6% for placebo; P=.19). However, vaccination significantly reduced the numbers of severe febrile illnesses (18.8% reduction; 95% confidence interval [CI], 7.4%-28.8%) and febrile upper respiratory tract illnesses (23.6% reduction; 95% CI, 12.7%-33.2%). Vaccination also led to fewer days of illness across all illness syndromes (22.9% reduction for febrile illnesses; 27.3% reduction for severe febrile illnesses), fewer days of work lost (17.9% reduction for severe febrile illnesses; 28.4% reduction for febrile upper respiratory tract illnesses), and fewer days with health care provider visits (24.8% reduction for severe febrile illnesses; 40.9% reduction for febrile upper respiratory tract illnesses). Use of prescription antibiotics and over-the-counter medications was also reduced across all illness syndromes. Vaccine recipients were more likely to experience runny nose or sore throat during the first 7 days after vaccination, but serious adverse events between the groups were not significantly different. The match between the type A(H3N2) vaccine strain and the predominant circulating virus strain (A/Sydney/05/97[H3N2]) for the 1997-1998 season was poor, suggesting that LAIV provided substantial cross-protection against this variant influenza A virus strain. CONCLUSION: Intranasal trivalent LAIV vaccine was safe and effective in healthy, working adults in a year in which a drifted influenza A virus predominated.

Administration, Intranasal↗