Local immune response to larvae of Rhipicephalus microplus in Santa Gertrudis cattle

This study investigated the local immune response at larval attachment sites in Santa Gertrudis cattle with low and high levels of tick resistance. Skin samples with tick larvae attached were collected from Santa Gertrudis cattle at the end of a period of 25 weekly infestations, when the animals manifested highly divergent tick-resistant phenotypes. There was a tendency for more CD3⁺ , CD4⁺ , CD8⁺ , CD25⁺ , γδ T cells and neutrophils to concentrate at larval tick attachment site in susceptible cattle than in resistant cattle but the differences were significant only for γδ T cells and CD4⁺ cells. Most of the cattle developed intra-epidermal vesicles at the larval attachment site but the predominant cell within or around the vesicles was the neutrophil in susceptible animals and eosinophil in the resistant animals. The monoclonal antibodies (mAbs) specific for CD45 and CD45 RO antigens reacted with skin leucocytes from a higher number of susceptible cattle than resistant cattle. Our data suggest that some of the cellular responses mounted at larval attachment site are not involved in tick protection. The mAbs specific for CD45 and CD45 RO directly, or a test for CD45 genotype might be developed as markers of tick susceptibility or resistance.

Peripheral cellular and humoral responses to infestation with the cattle tick Rhipicephalus microplus in Santa Gertrudis cattle

Resistance to cattle tick infestation in single-host ticks is primarily manifested against the larval stage and results in the immature tick failing to attach successfully and obtain a meal. This study was conducted to identify immune responses that characterize the tick-resistant phenotype in cattle. Thirty-five tick-naïve Santa Gertrudis heifers were used in this study, thirty of which were artificially infested for thirteen weeks with tick larvae while five animals remained at a tick-free quarantine property to serve as a control group. Following thirteen weeks of tick infestation, the animals in this trial exhibited highly divergent tick-resistant phenotypes. Blood samples collected throughout the trial were used to measure peripheral immune parameters: haematology, the percentage of cellular subsets comprising the peripheral blood mononuclear cell (PBMC) population, tick-specific IgG₁ and IgG₂ antibody titres, IgG1 avidity for tick antigens and the ability of PBMC to recognize and proliferate in response to stimulation with tick antigens in vitro. The tick-susceptible cattle developed significantly higher tick-specific IgG₁ antibody titres compared to the tick-resistant animals. These results suggest that the heightened antibody response either does not play a role in resistance or might contribute to increased susceptibility to infestation.

Immuno-fluorescence staining patterns of leukocyte subsets in the skin of taurine and indicine cattle

The immuno-staining patterns of skin leukocytes were investigated in three breeds of cattle: Holstein-Friesian, Brahman and Santa Gertrudis of similar age before and after tick infestation. The antibodies specific for CD45 and CD45RO reacted with cells in the skin of all Holstein-Friesian cattle but did not react with cells in the skin of any Brahman cattle. The same antibodies reacted with cells from the skin of four (CD45) and seven (CD45RO) of twelve Santa Gertrudis cattle. The antibodies specific for T cells and γδ subset of T cells recognized cells from all three breeds of cattle. The antibody specific for MHC class II molecules labelled cells of mostly irregular shape, presumably dermal dendritic cells and/or macrophages and Langerhans cells. The antibody specific for granulocytes (mAb CH138) reacted with cells only in sections cut from skin with lesions. The antibody specific for CD25(+) cells labelled regularly shaped cells that showed a wide range of intensities of staining.

Feeding performance of juvenile hatchery-reared spotted seatrout Cynoscion nebulosus

The feeding performance of individual hatchery-reared (HR) and wild juvenile spotted seatrout Cynoscion nebulosus was compared across a series of six 1·5 h feeding exposures over a 3 day period in a controlled experiment. The predation cycle served as a context for discerning feeding performance elements. The experimental design facilitated assessments of the effects of experience, motivation due to hunger or satiation and prey density and encounter frequency. Although feeding success improved significantly across successive trials for both groups of C. nebulosus, wild C. nebulosus successfully captured and consumed significantly more Palaemonetes spp. prey and completed most performance metrics more efficiently than HR C. nebulosus. Total exposure time decreased with experience for both groups of C. nebulosus; however, HR C. nebulosus took longer to complete feeding exposures. Underpinning this difference was the time spent by HR C. nebulosus in non-search mode and for completing various foraging behaviours. Nevertheless, juvenile HR C. nebulosus exhibited sufficient foraging plasticity to switch from a pelleted diet to live novel prey.

First report of a Trichinella papuae infection in a wild pig (Sus scrofa) from an Australian island in the Torres Strait region

Multiple Trichinella species are reported from the Australasian region although mainland Australia has never confirmed an indigenous case of Trichinella infection in humans or animals. Wildlife surveys in high-risk regions are essential to truly determine the presence or absence of Trichinella, but in mainland Australia are largely lacking. In this study, a survey was conducted in wild pigs from mainland Australia's Cape York Peninsula and Torres Strait region for the presence of Trichinella, given the proximity of a Trichinella papuae reservoir in nearby PNG. We report the detection of a Trichinella infection in a pig from an Australian island in the Torres Strait, a narrow waterway that separates the islands of New Guinea and continental Australia. The larvae were characterised as T. papuae (Kikori strain) by PCR and sequence analysis. No Trichinella parasites were found in any pigs from the Cape York Peninsula. These results highlight the link the Torres Strait may play in providing a passage for introduction of Trichinella parasites from the Australasian region to the Australian mainland.

Moving Canadian governmental policies beyond a focus on individual lifestyle: some insights from complexity and critical theories

This paper explores why Canadian government policies, particularly those related to obesity, are 'stuck' at promoting individual lifestyle change. Key concepts within complexity and critical theories are considered a basis for understanding the continued emphasis on lifestyle factors in spite of strong evidence indicating that a change in the environment and conditions of poverty isare needed to tackle obesity. Opportunities to get 'unstuck' from individual-level lifestyle interventions are also suggested by critical concepts found within these two theories, although getting 'unstuck' will also require cross-sectoral collective action. Our discussion focuses on the Canadian context but will undoubtedly be relevant to other countries, where health promoters and others engage in similar struggles for fundamental government policy change.

Local immune response against larvae of Rhipicephalus (Boophilus) microplus in Bos taurus indicus and Bos taurus taurus cattle

Bos taurus indicus cattle are less susceptible to infestation with Rhipicephalus (Boophilus) microplus than Bos taurus taurus cattle but the immunological basis of this difference is not understood. We compared the dynamics of leukocyte infiltrations (T cell subsets, B cells, major histocompatibility complex (MHC) class II-expressing cells, granulocytes) in the skin near the mouthparts of larvae of R. microplus in B. t. indicus and B. t. taurus cattle. Previously naïve cattle were infested with 50,000 larvae (B. t. indicus) or 10,000 larvae (B. t. taurus) weekly for 6 weeks. One week after the last infestation all of the animals were infested with 20,000 larvae of R. microplus. Skin punch biopsies were taken from all animals on the day before the primary infestation and from sites of larval attachment on the day after the first, second, fourth and final infestations. Infiltrations with CD3(+), CD4(+), CD8(+) and gammadelta T cells followed the same pattern in both breeds, showing relatively little change during the first four weekly infestations, followed by substantial increases at 7 weeks post-primary infestation. There was a tendency for more of all cell types except granulocytes to be observed in the skin of B. t. indicus cattle but the differences between the two breeds were consistently significant only for gammadelta T cells. Granulocyte infiltrations increased more rapidly from the day after infestation and were higher in B. t. taurus cattle than in B. t. indicus. Granulocytes and MHC class II-expressing cells infiltrated the areas closest to the mouthparts of larvae. A large volume of granulocyte antigens was seen in the gut of attached, feeding larvae.

Multifocal multi-organ ischaemia and infarction in a preterm baby due to maternal intravenous cocaine use: a case report

Introduction

Although the adverse effects of cocaine use in pregnancy are well recognised, we believe this case highlights the importance of considering the route of administration, and suggests the possibility of multifocal damage relating to intravenous use.

Case presentation

A Caucasian female baby of 29-weeks' gestation was spontaneously delivered and subsequently developed multi-organ failure considered unrelated to simple prematurity. Intensive care was re-orientated following the development of massive intraventricular haemorrhage.

Conclusion

This case illustrates the need for regular cranial ultrasound in babies of pregnancies at risk due to intravenous cocaine use and also the necessity of counselling women who misuse cocaine in the antenatal period. As such, this article will be of most interest to paediatric and obstetric staff.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Where's the beef? The role of cross-contamination in 4 chain restaurant-associated outbreaks of Escherichia coli O157:H7 in the Pacific Northwest

BACKGROUND

From March through August 1993, outbreaks of Escherichia coli O157:H7 occurred at 4 separate Oregon and Washington steak and salad bar restaurants affiliated with a single national chain.

OBJECTIVE

To determine the cause of outbreaks of E coli O157:H7 at 4 chain restaurants.

METHODS

Independent case-control studies were performed for each outbreak. Available E coli O157:H7 isolates were subtyped by pulse-field gel electrophoresis and by phage typing.

RESULTS

Infection was not associated with beef consumption at any of the restaurants. Implicated foods varied by restaurant but all were items served at the salad bar. Among the salad bar items, no single item was implicated in all outbreaks, and no single item seemed to explain most of the cases at any individual restaurant. Molecular subtyping of bacterial isolates indicated that the first 2 outbreaks, which occurred concurrently, were caused by the same strain, the third outbreak was caused by a unique strain, and the fourth was multiclonal.

CONCLUSIONS

Independent events of cross-contamination from beef within the restaurant kitchens, where meats and multiple salad bar items were prepared, were the likely cause of these outbreaks. Meat can be a source of E coli O157:H7 infection even if it is later cooked properly, underscoring the need for meticulous food handling at all stages of preparation.

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.

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.

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.

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.

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.

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.

Bacterial meningitis

In recent years, investigators have made significant advances in understanding the pathogenesis of bacterial meningitis, particularly with regard to understanding the cascade of biologic events that cause excessive inflammation within the central nervous system (CNS). Nevertheless, the most important event in the field of bacterial meningitis in the past decade is the dramatic decline in the incidence of Haemophilus influenzae meningitis in children as a result of the widespread use of the conjugated H. influenzae type b vaccine. Currently, the most important clinical challenge in this field is the emergence of the drug-resistant Streptococcus pneumoniae. This problem has significantly complicated initial management of patients with suspected bacterial meningitis. Preliminary data show promise with new conjugated S. pneumoniae vaccines.

Preferences for body type and body characteristics associated with attractive and unattractive bodies: Jackson and McGill revisited

The present investigation replicates Jackson and McGill's study (1996) and extends it by considering the effects of respondents' own height, weight, and body mass on perceptions of attractiveness. Results, although generally supportive of those found by Jackson and McGill, point to the influence of respondents' own physical characteristics in the process of perceptions of attractiveness: only 1 of Jackson and McGill's 3 (of a possible 19) differences between responses of African- and Euro-American women was corroborated (the importance of silky hair for Euro-American women), whereas a second difference (the importance of round buttocks for African-American women) disappeared when controlling for respondents' weight, height, and body mass. Although differences between the two investigations may be attributed to regional differences in the surveyed students (Michigan and North Carolina), the small effect of one's own weight, height, and body mass in assessing an other-sex person's attractiveness may reflect adherence to norms learned very early in life that are subject to regional variations.

Safety and effect on anti-Chlamydia pneumoniae antibody titres of a 1 month course of daily azithromycin in adults with coronary artery disease

A pilot study of azithromycin treatment following percutaneous coronary revascularization procedures was performed to assess safety and the effect of azithromycin treatment on anti-Chlamydia pneumoniae antibody titres. Patients were randomized to a 1 month course of azithromycin (total dose of 8.0 g) or placebo. Safety and compliance were assessed at 2 and 4 weeks and serological testing was performed on samples obtained at enrolment and at 6 months post-enrolment. Azithromycin was well tolerated at this dose. No effect of treatment on antibody titres was demonstrated. These results support further clinical trials to assess the effect of azithromycin treatment on cardiovascular disease outcomes.

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.

Safety of a trivalent live attenuated intranasal influenza vaccine, FluMist, administered in addition to parenteral trivalent inactivated influenza vaccine to seniors with chronic medical conditions

We conducted a randomized, double-blind trial to evaluate the safety and tolerability of a live attenuated cold adapted trivalent intranasal influenza vaccine, FluMist, compared with intranasal placebo when given in addition to a licensed trivalent injected inactivated influenza vaccine (TIV). The study population consisted of persons 65 years of age and older with chronic cardiovascular or pulmonary conditions or diabetes mellitus. During the 7 days post-vaccination, sore throat was reported on at least one day by 15% (15/100) of FluMist recipients compared with 2% (2/100) of intranasal placebo recipients (p = 0.001). No other reactogenicity symptom was statistically associated with receipt of FluMist. Among this group, FluMist was safe and well tolerated when administered with TIV.

Safety of revaccination with pneumococcal polysaccharide vaccine

CONTEXT

Revaccination of healthy adults with pneumococcal polysaccharide vaccine (PPV) within several years of first vaccination has been associated with a higher than expected frequency and severity of local injection site reactions. The risk of adverse events associated with revaccination of elderly and chronically ill persons 5 or more years after first vaccination, as is currently recommended, has not been well defined.

OBJECTIVE

To determine whether revaccination with PPV at least 5 years after first vaccination is associated with more frequent or more serious adverse events than those following first vaccination.

DESIGN

Comparative intervention study conducted between April 1996 and August 1997.

PARTICIPANTS

Persons aged 50 to 74 years either who had never been vaccinated with PPV (n = 901) or who had been vaccinated once at least 5 years prior to enrollment (n = 513).

INTERVENTION

PPV vaccination.

MAIN OUTCOME MEASURES

Postvaccination local injection site reactions and prevaccination concentrations of type-specific antibodies.

RESULTS

Those who were revaccinated were more likely than those who received their first vaccinations to report a local injection site reaction of at least 10.2 cm (4 in) in diameter within 2 days of vaccination: 11% (55/513) vs 3% (29/901) (relative risk [RR], 3.3; 95% confidence interval [CI], 2.1-5.1). These reactions resolved by a median of 3 days following vaccination. The highest rate was among revaccinated patients who were immunocompetent and did not have chronic illness: 15% (33/228) compared with 3% (10/337) among comparable patients receiving their first vaccinations (RR, 4.9; 95% CI, 2.4-9.7). The risk of these local reactions was significantly correlated with prevaccination geometric mean antibody concentrations.

CONCLUSIONS

Physicians and patients should be aware that self-limited local injection site reactions occur more frequently following revaccination compared with first vaccination; however, this risk does not represent a contraindication to revaccination with PPV for recommended groups.

Influence of family history on clinical expression of Tourette's syndrome

OBJECTIVE

To determine the influence of family history on clinical expression of Tourette's syndrome (TS).

BACKGROUND

Recent studies have suggested that clinical expression of TS is similar among sporadic (SP) and familial patients but may be influenced by bilineal (BIL) transmission of tics or obsessive-compulsive behavior (OCB) in high-density pedigrees.

METHODS

The authors used family history methodology, supported by direct examination of affected relatives in 73% of familial patients, to determine the frequency of SP TS, and of unilineal (UNL) and BIL transmission of tics or OCB in 111 consecutively ascertained juvenile TS patients. For individuals in each group, severity of tics, attention deficit hyperactivity disorder (ADHD), and OCB were assessed at presentation and after a mean follow-up interval of 2.6 years, using the Tourette's Syndrome Global Scale and the Clinical Global Impression scales. The phenomenology of OCB was evaluated using the symptom checklist of the Children's Yale-Brown Obsessive Compulsive Scale.

RESULTS

The authors documented BIL transmission of tics in seven patients (6%). Patient age and sex were similar for the SP (n = 21; 19%), UNL (n = 66; 59%), and BIL (n = 24; 22%) groups, as was ADHD and tic severity at presentation and follow-up. Severity of OCB differed significantly between groups, with moderate to severe OCB affecting 5% of SP, 12% of UNL, and 37% of BIL patients at presentation (p = 0.007), and 5% of SP, 17% of UNL, and 54% of BIL patients at follow-up (p = 0.0001). Relative to UNL or SP patients, BIL patients were more likely to exhibit self-injurious behaviors (p = 0.0005).

CONCLUSIONS

OCB is less prominent in SP than in familial TS, perhaps reflecting a more restricted pathophysiology in this subgroup. Although BIL transmission of tics is relatively infrequent in consecutive TS pedigrees, cotransmission of OCB from an otherwise unaffected parent is common and significantly influences development of OCB and self-injurious behaviors, but not tics, in offspring. Genetic heterogeneity, epigenetic factors, and gene-environment interactions may play a more important role than genetic dosage effects in determining tic severity in TS.

Lack of association between first myocardial infarction and past use of erythromycin, tetracycline, or doxycycline

To evaluate the association of prior treatment with antibiotics active against Chlamydia pneumoniae with the risk for incident myocardial infarction, we conducted a population-based case-control study. We found that use of erythromycin, tetracycline, or doxycycline during the previous 5 years was not associated with risk for first myocardial infarction. These results suggest little or no association between the use of these antibiotics and the risk for first myocardial infarction in the primary prevention setting.

Use of an automated pharmacy system and patient registries to recruit HMO enrollees for an influenza campaign

OBJECTIVE

To develop methods to identify, recruit, and vaccinate HMO enrollees at increased risk for influenza-related complications as part of a comprehensive influenza campaign.

SETTING

Group Health Cooperative (GHC) is a large, membership-governed, managed care organization that serves 395,000 members in the Puget Sound area.

APPROACH

An automated pharmacy system and patient data registries were used to identify enrollees with chronic illness. Enrollees with chronic illness and all enrollees 65 years of age and older were considered "high-risk" enrollees to be recruited for vaccination. Postcard reminders coupled with a publicity and education campaign were used to recruit high-risk enrollees to special influenza clinics.

RESULTS

Our approach identified 2.5% of children (persons < 18 years of age) and 10.5% of adults (persons 18 to 65 years of age) as chronically ill and thus at high risk for influenza-related complications. Most high-risk children were identified through prescriptions for steroids, autonomic inhalers, or both or because they were enrolled in the asthma registry. Most high-risk adults were identified because of prescriptions for steroids, insulin, or oral hypoglycemic agents; because they had received pneumococcal vaccine; or because they were enrolled in the diabetes registry. Influenza coverage rates for all seniors (persons > or = 65 years of age) increased from 34% in 1984 to more than 72% in the 1996-1997 campaign year. Coverage rates were much lower for high-risk children (36%) and adults (46%).

CONCLUSIONS

Influenza coverage rates can still be substantially improved for adults younger than 65 years of age and children at high risk for influenza-related complications.

A comprehensive influenza campaign in a managed care setting

Group Health Cooperative, a large, membership-governed, staff model health maintenance organization (HMO), has designed a comprehensive influenza campaign for identifying, recruiting and vaccinating enrollees at increased risk for influenza-related complications. The Cooperative's Centre for Health Promotion is responsible for the overall planning, implementation and evaluation of the influenza campaign. The model for delivering influenza immunizations has been designed to build on the strengths and capabilities of a staff model HMO with sophisticated automated information systems. The model permits area medical centres (AMCs) and physicians to use the materials and intervention strategies generated by the Centre for Health Promotion, while at the same time allowing them flexibility to design and use their own intervention strategies to increase compliance. More importantly, the model reduces resource requirements on AMCs and physicians to plan and maintain internal immunization efforts. Recommendations for improving the influenza campaign are discussed.

Prevention of chickenpox in reproductive-age women: cost-effectiveness of routine prenatal screening with postpartum vaccination of susceptibles

OBJECTIVE

To evaluate economic and clinical outcomes of a program of routine prenatal serotesting for varicella and postpartum vaccination of seronegative women.

METHODS

An analytic cost-effectiveness model was constructed to compare the current strategy of no serotesting with 1) selective serotesting of pregnant women without a prior history of chickenpox and 2) serotesting of all pregnant women. In both serotesting strategies, seronegative women were vaccinated postpartum. The model followed a hypothetical cohort of 4 million women over 20 years. Costs and chickenpox disease outcomes during and outside of subsequent pregnancies were considered. The incremental cost-effectiveness (cost per adult chickenpox case prevented) of selective serotesting compared with the current strategy was measured.

RESULTS

Compared to no testing, selective serotesting would prevent 43% (48,577 of 112,654) of adult chickenpox cases, save $21.8 million in discounted medical and work loss costs from the societal perspective, and cost $1126 per case prevented from the health payer's perspective (medical costs only). The model was sensitive to varicella seroprevalence and incidence of chickenpox among susceptible women but was relatively insensitive to the cost of serologic testing and vaccination. Compared with selective serotesting, the serotest-all strategy would prevent an additional 15,645 cases, at a societal cost of $7653 per additional case prevented.

CONCLUSION

The selective serotesting strategy could prevent nearly half of chickenpox cases among this cohort and is cost-saving from the societal perspective. From the health payer's perspective, it compares favorably with other generally accepted preventive practices. It should be considered for prevention of chickenpox among women of childbearing age.

Theileria annulata: the expression of two novel macroschizont antigens on the surface of infected mononuclear cells differs during in vitro attenuation of a virulent cell line

The first part of this study of the biological mechanisms underlying attenuation of virulent Theileria annulata macroschizont-infected cell lines screened four pairs of T. annulata (Hisar) in vivo- and in vitro-derived macroschizont-infected cell lines (lines) and identified a single in vivo-derived line, which induced lethal tropical theileriosis. The other seven lines were relatively avirulent. Analysis of the clinical, hematological, and parasitological responses of cattle immunized with different passages of the virulent line after in vitro culture showed that it was partly attenuated by passage (p) 50 and avirulent by p130. Clones representing the three glucose phosphate isomerase (GPI) isotypes, which constituted the newly isolated virulent culture, were obtained from p3 by limiting dilution; p50 and p130 consisted of one isotype. The second part of the study raised monoclonal antibodies (MAbs) against macroschizont-infected cells, as reagents for detecting antigenic differences between virulent and avirulent parasites, and identified two MAbs that recognized the surface of infected cells as well as macroschizonts. MAb EU1 recognized an antigen expressed by all the lines tested, whether in vitro- or in vivo-derived, whether uncloned or cloned, and irrespective of extent of subpassage in culture. MAb EU106 recognized an antigen whose expression by the virulent line and its clones disappeared on passage in culture. This antigen was not expressed at all by the avirulent in vitro-derived line prepared with cells from the same calf. Both antigens were expressed by lines infected with other stocks of T. annulata, including two lines known to induce lethal disease. The different profiles of expression of the two novel antigens, recognized by MAbs EU1 and EU106, by the line undergoing attenuation suggest (1) that the two antigens interact differently with the bovine immune system; and (2) that there are two, very different, potential roles for these antibodies in the development of vaccines against T. annulata infections.

Illnesses and absence due to illness among children attending child care facilities in Seattle-King County, Washington

OBJECTIVES

Although much of the economic impact of child care-associated illness in the United States is due to parents' time lost from work, there are no data on the incidence of absence due to illness among children in various types of out-of-home child care settings in the United States. The goals of this study were to compare the incidence of illness and absence due to illness among children attending child care homes (CCHs) and child care centers (CCCs).

METHODS

From July 1992 through June 1993, child care providers from 91 CCHs and 41 CCCs in Seattle-King County, Washington, provided information on absenteeism and illness for 96 792 child-weeks of observation.

RESULTS

The age-adjusted incidence of provider-reported illness episodes among children in CCHs (10.4 episodes per 100 child-weeks) was greater than that among children in CCCs (6.7 episodes per 100 child-weeks). The incidence density ratio of illness among children <1 year of age in comparison to those >/=5 years of age in CCCs (4.5) was greater than that among similar groups in CCHs (2.3). The age-adjusted incidence of absence due to illness among children in CCHs (5.1 days per 100 child-weeks) was less than that among children in CCCs (8.9 days per 100 child-weeks).

CONCLUSIONS

Results comparing the incidence of illness between children in various types of child care settings may be influenced by information sources. The incidence of illness among children in CCHs may be greater than that among children in CCCs. The increased incidence of absence due to illness among children in CCCs compared with that among children in CCHs probably reflects differences in exclusion and attendance policies and practices between these two types of settings.

Isolation of Chlamydia pneumoniae from a carotid endarterectomy specimen

Chlamydia pneumoniae has been associated with atherosclerotic cardiovascular disease by both seroepidemiologic studies and direct detection of the organism in atherosclerotic plaque by electron microscopy (EM), immunocytochemistry (ICC), and polymerase chain reaction (PCR). Despite the frequent detection of the organism in atheromatous cardiovascular specimens by these methods, only 1 cardiovascular isolate of C. pneumoniae, obtained from a coronary artery, has been previously reported. This study reports the isolation of C. pneumoniae from a prospectively obtained carotid endarterectomy specimen. The organism appears to be identical to other C. pneumoniae isolates by EM morphology, reactivity to species-specific monoclonal antibodies, and Southern hybridization analysis of chromosomal digests using C. pneumoniae-specific DNA probes. C. pneumoniae was detected by PCR or ICC (or both) in 11 (69%) of 16 other endarterectomy specimens tested by both of these methods. These results provide further evidence for an association of C. pneumoniae and atherosclerosis by confirming the presence of viable bacteria within atherosclerotic plaque.

HIV-positive women living in the metropolitan Toronto area: their experiences and perceptions related to HIV testing. The HIV Women's Study Group

Forty HIV-positive women from diverse socioeconomic backgrounds were interviewed. Most (90%) did not perceive themselves to be at risk of HIV infection prior to knowing their HIV-positive status. The majority (61%) were tested because they developed symptoms, or because someone with whom they were intimate, or their child, tested positive for HIV or became ill. The majority (93%) of the women interviewed indicated that they did not receive both pre- and post-test counselling. The findings from this study suggest that encouraging individuals to be tested if they have engaged in "at risk" activities will not be appropriate for individuals who have no perception of risk, and other strategies to encourage appropriate testing may be needed. This research also suggests that continued emphasis needs to be placed on the counselling process, and that consideration may need to be given to multiple counselling sessions to ensure individuals clearly understand the information provided.

Bovine cells infected in vivo with Theileria annulata express CD11b, the C3bi complement receptor

Bovine cells from cattle infected with Theileria annulata were phenotyped with monoclonal antibodies recognizing bovine leukocyte antigens. Macroschizont-infected, transformed cell lines prepared from peripheral blood mononuclear cells of cattle, infected with sporozoites, were assessed by flow cytometry; parasitized cells in tissues from infected cattle were examined by immunocytochemical techniques. Co-expression of markers for different cell lineages by the cell lines precluded a definite conclusion as to their phenotypic origins. For, while the pattern of leukocyte antigens expressed by these in vivo-derived schizont-infected cells, which included CD11b, was indicative of a myeloid origin, the possibility that they were NK cells could not be excluded. The monoclonal antibody (MAb) IL-A15, which recognizes CD11b, reacted with a high proportion of parasitized cells in sections of tissues from infected cattle at all stages of acute disease. Mononuclear cells infected with parasites at all stages of differentiation, from macroschizont to microschizont, expressed CD11b. Such parasitized cells occurred throughout the lymphoid tissues, being found in the thymus, spleen and lymph nodes, particularly the prescapular node draining the site of infection, the hepatic, mesenteric and precrural nodes, as well as in the reticulo-endothelial tissue of the liver, kidney, lung, abomasum, adrenal and pituitary glands. These observations provided the first evidence for a myeloid origin for the parasitized T. annulata cells found in infected bovine tissues and blood and suggested a mechanism whereby schizonts could transfer from cell to cell during mechanical infection with schizont-infected cells.

Specificity of detection of Chlamydia pneumoniae in cardiovascular atheroma: evaluation of the innocent bystander hypothesis

Chlamydia pneumoniae has been detected in atherosclerotic plaque, raising the question of whether this detection is specific to atheromatous tissue. To evaluate this question, we tested cardiovascular and non-cardiovascular tissue samples from 38 autopsy cases by polymerase chain reaction and immunocytochemistry. We also tested 33 granuloma biopsy specimens, as the organism has been detected in macrophages. C. pneumoniae was detected in coronary artery tissue from 13 (34%), lung from 5 (13%), liver from 4 (10%), and spleen from 2 (5%) of the 38 autopsy cases (P < 0.05 for comparison of proportion of positive coronary arteries with that of each of the other types of tissue). Of the 21 cases with at least one positive tissue sample, 11 had only a positive cardiovascular tissue (coronary artery, venous bypass graft, or myocardium), 7 had both cardiovascular and non-cardiovascular positive tissues, and 3 had only a non-cardiovascular positive tissue. C. pneumoniae was thus detected relatively infrequently in non-cardiovascular tissues, and its detection in these tissues was usually in association with its detection in cardiovascular tissue from the same patient. The organism was also infrequently detected in granulomatous tissue (3/33 specimens). These findings demonstrate that C. pneumoniae is more frequently found in atherosclerotic than normal tissue and support the hypothesis that C. pneumoniae has a role in the pathogenesis of atherosclerosis.

HIV-positive women living in the metropolitan Toronto area: their experiences and perceptions related to HIV testing. The HIV Women's Study Group

Forty HIV-positive women from diverse socioeconomic backgrounds were interviewed. Most (90%) did not perceive themselves to be at risk of HIV infection prior to knowing their HIV-positive status. The majority (61%) were tested because they developed symptoms, or because someone with whom they were intimate, or their child, tested positive for HIV or became ill. The majority (93%) of the women interviewed indicated that they did not receive both pre- and post-test counselling. The findings from this study suggest that encouraging individuals to be tested if they have engaged in "at risk" activities will not be appropriate for individuals who have no perception of risk, and other strategies to encourage appropriate testing may be needed. This research also suggests that continued emphasis needs to be placed on the counselling process, and that consideration may need to be given to multiple counselling sessions to ensure individuals clearly understand the information provided.

Salivary antigens of the cat flea, Ctenocephalides felis felis

The cat flea, Ctenocephalides felis felis, is the major cause of flea bite hypersensitivity (FBH) in dogs and cats, yet little progress has been reported on identifying the antigens responsible. We obtained flea salivary antigens by washing secretions from containers probed by the mouthparts of fleas, and by extracting whole flea salivary glands. Mice were exposed to feeding fleas to generate antibodies to salivary antigens injected in vivo. The sera were tested for antibodies against the salivary antigens described and against a whole flea extract; in indirect ELISA, antibodies to salivary secretions were detected in 60% of the sera from mice exposed to feeding fleas. These sera identified four protein bands at apparent MW 56, 54, 42 and 40 K which corresponded to prominent protein bands in whole salivary gland extracts identified by protein staining after SDS-PAGE. Fixed sections of whole fleas exposed to the antisera showed that only structures within the salivary glands were identified. The salivary secretions and gland extracts are now being used to study immune responses of dogs suffering from FBH.

In vitro activities of azithromycin, clarithromycin, and other antibiotics against Chlamydia pneumoniae

The in vitro susceptibilities of Chlamydia pneumoniae isolates to macrolide, tetracycline, and quinolone antibiotics were determined. Tetracycline, clarithromycin, and erythromycin had the lowest MICs in the first cell culture passage. Azithromycin required the lowest concentration for complete inhibition of inclusion formation on the second pass into antibiotic-free medium, likely reflecting its high intracellular concentrations.