Schistosoma mansoni-specific immune responses and allergy in Uganda.

Low allergy-related disease (ARD) prevalence in low-income countries may be partly attributed to helminth infections. In the Schistosoma mansoni (Sm)-endemic Lake Victoria islands (Uganda), we recently observed positive helminth-allergy associations, despite low ARD prevalence. To understand how Sm-induced cytokine and antibody profiles might influence allergic response profiles in this population, we assessed Schistosoma worm (SWA)- and egg antigen (SEA)-specific Th1 (IFN-γ), Th2 (IL-5, IL-13) and regulatory (IL-10) cytokine profiles (n = 407), and total (n = 471), SWA-, SEA- and allergen (house dust mite [HDM] and cockroach)-specific (as)IgE and IgG4 profiles (n = 2117) by ELISA. Wheeze was inversely associated with SWA-specific IFN-γ (P < .001) and IL-10 (P = .058), and SEA-specific IL-5 (P = .004). Conversely, having a detectable asIgE response was positively associated with SWA-specific IL-5 (P = .006) and IL-10 (P < .001). Total, SWA-, SEA- and allergen-specific IgE and IgG4 responses were higher among Sm Kato-Katz positive (SmKK+) and skin prick test (SPT)+ individuals compared to SmKK- and SPT- individuals. However, total and asIgG4/IgE ratios were lower among SPT+ and wheezing individuals. We conclude that, in this population, helminth-induced antibody and cytokine responses may underlie individual positive helminth-atopy associations, while the overall IgG4-IgE balance may contribute to the low overall prevalence of clinical allergies in such settings.

Helminths are positively associated with atopy and wheeze in Ugandan fishing communities: results from a cross-sectional survey.

BACKGROUND: Parasitic helminths are potent immunomodulators and chronic infections may protect against allergy-related disease and atopy. We conducted a cross-sectional survey to test the hypothesis that in heavily helminth-exposed fishing villages on Lake Victoria, Uganda, helminth infections would be inversely associated with allergy-related conditions. METHODS: A household survey was conducted as baseline to an anthelminthic intervention trial. Outcomes were reported wheeze in last year, atopy assessed both by skin prick test (SPT) and by the measurement of allergen-specific IgE to dust mites and cockroach in plasma. Helminth infections were ascertained by stool, urine and haemoparasitology. Associations were examined using multivariable regression. RESULTS: Two thousand three hundred and sixteen individuals were surveyed. Prevalence of reported wheeze was 2% in under-fives and 5% in participants ≥5 years; 19% had a positive SPT; median Dermatophagoides-specific IgE and cockroach-specific IgE were 1440 and 220 ng/ml, respectively. S. mansoni, N. americanus, S. stercoralis, T. trichiura, M. perstans and A. lumbricoides prevalence was estimated as 51%, 22%, 12%, 10%, 2% and 1%, respectively. S. mansoni was positively associated with Dermatophagoides-specific IgE [adjusted geometric mean ratio (aGMR) (95% confidence interval) 1.64 (1.23, 2.18)]; T. trichiura with SPT [adjusted odds ratio (aOR) 2.08 (1.38, 3.15)]; M. perstans with cockroach-specific IgE [aGMR 2.37 (1.39, 4.06)], A. lumbricoides with wheeze in participants ≥5 years [aOR 6.36 (1.10, 36.63)] and with Dermatophagoides-specific IgE [aGMR 2.34 (1.11, 4.95)]. No inverse associations were observed. CONCLUSIONS: Contrary to our hypothesis, we found little evidence of an inverse relationship between helminths and allergy-related outcomes, but strong evidence that individuals with certain helminths were more prone to atopy in this setting.

Human eosinophils modulate peripheral blood mononuclear cell response to Schistosoma mansoni adult worm antigen in vitro.

High numbers of eosinophils are observed in parasitic infections and allergic diseases, where they are proposed to be terminally differentiated effector cells that play beneficial role in host defence, or cause harmful inflammatory response. Eosinophils have been associated with killing of schistosomulae in vitro, but there is growing evidence that eosinophils can play additional immuno-regulatory role. Here, we report results of a study that examines peripheral blood mononuclear cell (PBMC) cytokine responses to Schistosoma mansoni adult worm antigen (SWA) when stimulated alone or enriched with autologous eosinophils. Production of the Th-2 type cytokines interleukin (IL)-4, IL-5 and IL-13 was lower (P = 0·017, 0·018 and <0·001, respectively) in PBMC + eosinophil cultures than in PBMC-only cultures stimulated with SWA. Substantial levels of IL-13, IL-10, interferon gamma and tumour necrosis factor alpha were recorded in cultures of eosinophils, but none of these cytokines showed significant association with the observed eosinophil-induced drop in cytokine responses of PBMC. Transwell experiments suggested that the observed effect is due to soluble mediators that downmodulate production of Th-2 type cytokines. This study shows that eosinophils may down-modulate schistosome-specific Th-2 type cytokine responses in S. mansoni-infected individuals. The mechanism of this immune modulation remains to be elucidated.

The Medical Research Council (UK)/Uganda Virus Research Institute Uganda Research Unit on AIDS--'25 years of research through partnerships'.

For the past 25 years, the Medical Research Council/Uganda Virus Research Institute Uganda Research Unit on AIDS has conducted research on HIV-1, coinfections and, more recently, on non-communicable diseases. Working with various partners, the research findings of the Unit have contributed to the understanding and control of the HIV epidemic both in Uganda and globally, and informed the future development of biomedical HIV interventions, health policy and practice. In this report, as we celebrate our silver jubilee, we describe some of these achievements and the Unit's multidisciplinary approach to research. We also discuss the future direction of the Unit; an exemplar of a partnership that has been largely funded from the north but led in the south.

Correlation between the temperature dependence of intrinsic MR parameters and thermal dose measured by a rapid chemical shift imaging technique.

In order to investigate simultaneous MR temperature imaging and direct validation of tissue damage during thermal therapy, temperature-dependent signal changes in proton resonance frequency (PRF) shifts, R(2)* values, and T1-weighted amplitudes are measured from one technique in ex vivo tissue. Using a multigradient echo acquisition and the Stieglitz-McBride algorithm, the temperature sensitivity coefficients of these parameters are measured in each tissue at high spatiotemporal resolutions (1.6 x 1.6 x 4 mm 3,≤ 5sec) at the range of 25-61 °C. Non-linear changes in MR parameters are examined and correlated with an Arrhenius rate dose model of thermal damage. Using logistic regression, the probability of changes in these parameters is calculated as a function of thermal dose to determine if changes correspond to thermal damage. Temperature sensitivity of R(2)* and, in some cases, T1-weighted amplitudes are statistically different before and after thermal damage occurred. Significant changes in the slopes of R(2)* as a function of temperature are observed. Logistic regression analysis shows that these changes could be accurately predicted using the Arrhenius rate dose model (Ω = 1.01 ± 0.03), thereby showing that the changes in R(2)* could be direct markers of protein denaturation. Overall, by using a chemical shift imaging technique with simultaneous temperature estimation, R(2)* mapping and T1-W imaging, it is shown that changes in the sensitivity of R(2)* and, to a lesser degree, T1-W amplitudes are measured in ex vivo tissue when thermal damage is expected to occur. These changes could possibly be used for direct validation of thermal damage in contrast to model-based predictions.

Effects of deworming during pregnancy on maternal and perinatal outcomes in Entebbe, Uganda: a randomized controlled trial.

BACKGROUND: Helminth infections during pregnancy may be associated with adverse outcomes, including maternal anemia, low birth weight, and perinatal mortality. Deworming during pregnancy has therefore been strongly advocated, but its benefits have not been rigorously evaluated. METHODS: In Entebbe, Uganda, 2507 pregnant women were recruited to a randomized, double-blind, placebo-controlled trial investigating albendazole and praziquantel in a 2 x 2 factorial design [ISRCTN32849447]. Hematinics and sulphadoxine-pyrimethamine for presumptive treatment of malaria were provided routinely. Maternal and perinatal outcomes were recorded. Analyses were by intention to treat. RESULTS: At enrollment, 68% of women had helminths, 45% had hookworm, 18% had Schistosoma mansoni infection; 40% were anemic (hemoglobin level, <11.2 g/dL). At delivery, 35% were anaemic; there was no overall effect of albendazole (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.79-1.15) or praziquantel (OR, 1.00; 95% CI, 0.83-1.21) on maternal anemia, but there was a suggestion of benefit of albendazole among women with moderate to heavy hookworm (OR, 0.45; 95% CI, 0.21-0.98; P=.15 for interaction). There was no effect of either anthelminthic treatment on mean birth weight (difference in mean associated with albendazole: -0.00 kg; 95% CI, -0.05 to 0.04 kg; difference in mean associated with praziquantel: -0.01 kg; 95% CI, -0.05 to 0.04 kg) or on proportion of low birth weight. Anthelminthic use during pregnancy showed no effect on perinatal mortality or congenital anomalies. CONCLUSIONS: In our study area, where helminth prevalence was high but infection intensity was low, there was no overall effect of anthelminthic use during pregnancy on maternal anemia, birth weight, perinatal mortality, or congenital anomalies. The possible benefit of albendazole against anemia in pregnant women with heavy hookworm infection warrants further investigation.

A novel COMP mutation in an Inuit patient with pseudoachondroplasia and severe short stature.

Pseudoachondroplasia (PSACH) is an autosomal dominant skeletal dysplasia, generally identified clinically at two years of age due to decreased linear growth and a waddling gait. Radiographic features include small and irregular epiphyses, with metaphyseal changes of the long bones and characteristic vertebral changes. Mutations in the COMP gene cause PSACH and some cases of multiple epiphyseal dysplasia. Mutations generally cluster in the calmodulin-like repeat regions of the gene. Mutations in exon 13 (encoding the seventh calmodulin-like repeat) have been associated with severe short stature (-6 SD) in PSACH. We examined an Inuit boy with PSACH and severe short stature. Height essentially remained at -1 SD on the PSACH growth curve (-7.5 SD on a normal growth curve at 10.5 years). Analysis of COMP in our patient revealed a previously undescribed heterozygous A>T substitution in exon 8, at nucleotide 812. This change in the sequence resulted in replacement of a highly conserved and negatively charged aspartic acid with an uncharged, hydrophobic valine at amino acid position 271. Both unaffected parents were negative for this genetic change. This exon encodes the first calmodulin-like repeat, which has not been previously implicated in severe short stature. We propose that this novel missense substitution is responsible for the phenotype of this patient.

Adaptation of Western measures of cognition for assessing 5-year-old semi-urban Ugandan children.

BACKGROUND: The majority of available psychometric tests originates from the Western World and was designed to suit the culture, language, and socio-economic status of the respective populations. Few tests have been validated in the developing world despite the growing interest in examining effects of biological and environmental factors on cognitive functioning of children in this setting. AIMS: The present study aimed at translating and adapting Western measures of working memory, general cognitive ability, attention, executive function, and motor ability in order to obtain a cognitive instrument suitable for assessing 5-year-old semi-urban Ugandan children. This population represents a particular assessment challenge as school enrolment is highly variable at this age in this setting and many children are unused to a formal educational setting. METHODS: Measures of the above domains were selected, translated, and modified to suit the local culture, education, and socio-economic background of the target population. The measures were piloted and then administered to semi-urban Ugandan children aged 4;6-5;6, who included children who had started and not yet started school. RESULTS: Analysis of validity and reliability characteristics showed that 8 (at least one from each domain) out of the 11 measures were successfully adapted on the basis that they showed adequate task comprehension, optimum levels of difficulty to demonstrate individual and group differences in abilities, sensitivity to effects of age and education, and good internal as well as test-retest reliability. CONCLUSION: Translation and adaptation are realistic and worthwhile strategies for obtaining valid and reliable cognitive measures in a resource-limited setting.

A golgi apparatus associated with mating in Tetrahymena pyriformis.

The classical Golgi apparatus has not been observed in the several strains of Tetrahymena pyriformis examined in this laboratory at the ultrastructural level when the ciliates are grown vegetatively. However, sexually active strains, when starved for the purpose of inducing conjugation, contain stacked saccules in the oral region. When such opposite mating types are mixed for mating, the stacked saccules become swollen at their ends and vesicles appear to pinch off from them. These bodies possess the configuration of the classical Golgi apparatus of other eucells. Vesicles seem to be formed from the saccules just prior to, and toward the end of conjugation, suggesting a relationship with the mating process.

Cigarette smoke: the effect of residue on mitochondrial structure.

Cigarette smoke residue is ciliatoxic to Tetrahymena pyriformis. Principal sites of activity are the mitochondria of the cell. The internal membranes of the mitochondria are degraded with time, correlating well with loss of ciliary activity and cell death.

Central ray deficiency with extensive syndactyly: a dilemma for classification.

Split Hand Foot Malformation (SHFM) (cleft hand/foot, central ray deficiency) is a complex, highly variable anomaly involving the hands and/or feet. A clinical epidemiologic study of split hand/foot (central ray deficiency) of the Manitoba population identified a subset of patients who did not present with either typical or atypical split hand. Clinically, some patients presented with "mitten hand" syndactyly; the deficiency was not recognized before imaging. In this paper, we identify additional similarly affected literature cases, review existing classifications of split hand and syndactyly and attempt to classify these patients. This group presents a challenge for classification and genetic counseling. General classifications permit inclusion of patients with diverse phenotypes; however, details are overlooked. Osseous fusions and disorganization of osseous components complicate classification. Many of these patients had findings that overlapped different subtypes within existing classifications. This cohort highlights the importance of imaging patients with distal limb anomalies. An effective classification scheme should include relevant clinical and radiographic findings in order to assist clinicians following these patients.

Is birth weight associated with blood pressure among African children and adolescents? A systematic review.

There is substantial evidence of an inverse association between birth weight and later blood pressure (BP) in populations from high-income countries, but whether this applies in low-income countries, where causes of low birth weight are different, is not certain. OBJECTIVE: We conducted a review of the evidence on the relationship between birth weight and BP among African children and adolescents. Medline, EMBASE, Global Health and Web of Science databases were searched for publications to October 2016. Papers reporting the relationship between birth weight and BP among African children and adolescents were assessed. Bibliographies were searched for further relevant publications. Selected papers were summarized following the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. In total, 16 papers from 13 studies conducted in nine African countries (Nigeria, Republic of Seychelles, Gambia, Democratic Republic of Congo, Cameroon, South Africa, Algeria, Zimbabwe and Angola) were reviewed. Eight studies were cohorts, while five were cross-sectional. The relationship between birth weight and later BP varied with age of the participants. Studies in neonates showed a consistently positive association, while predominantly inverse associations were seen among children, and studies in adolescents were inconsistent. Based on the limited number of studies identified, the relationship between birth weight and later BP may vary with age in African children and adolescents. Not all studies adequately controlled for confounding, notably gender or age. Whether the inverse relationship between birth weight and BP in later life observed in Western settings is also seen in Africa remains unclear.

Characterization of plastic and boron carbide additive manufactured neutron collimators.

Additive manufacturing techniques allow for the production of materials with complicated geometries with reduced costs and production time over traditional methods. We have applied this technique to the production of neutron collimators for use in thermal and cold neutron scattering instrumentation directly out of boron carbide. We discuss the design and generation of these collimators. We also provide measurements at neutron scattering beamlines which serve to characterize the performance of these collimators. Additive manufacturing of parts using neutron absorbing material may also find applications in radiography and neutron moderation.

The value of wide-needle aspiration in the diagnosis of tuberculous lymphadenitis in Africa.

OBJECTIVES: To evaluate wide-needle (19-gauge) aspiration in the diagnosis of tuberculous lymphadenitis. SETTING: Department of Surgery, University Teaching Hospital, Lusaka, Zambia. PATIENTS: Three hundred and four patients presenting to one surgeon for diagnostic surgical biopsy of a peripheral lymph node during 1989-1990. DESIGN: Prospective study in which wide-needle aspiration routinely preceded open surgical biopsy. MAIN OUTCOME MEASURES: Histology and mycobacterial culture of the surgically biopsied lymph node; HIV-1 serology; successful aspiration of material, naked-eye appearance of aspirate, presence of acid-fast bacilli and/or microscopic caseation in the aspirate. RESULTS: One hundred and eighty-eight out of 304 (61.8%) patients had histologically and/or culture-proven tuberculous lymphadenitis, of whom 155 out of 183 (84.7%) tested HIV-1-seropositive. Material was successfully aspirated from 180 out of 188 (95.7%) of patients with proven tuberculous lymphadenitis. Macroscopic caseation, diagnosable on naked-eye examination alone of the aspirate, was present in 49 out of 120 (40.8%) consecutive aspirates from tuberculous nodes. Acid-fast bacilli and/or microscopic caseation were seen in 116 out of 155 (74.8%) aspirates from tuberculous nodes for which smears stained both by Ziehl-Nielsen and haematoxylin & eosin were available. CONCLUSIONS: It is recommended that all patients with suspected tuberculous lymphadenitis in Africa, undergo wide-needle aspiration before surgical biopsy or empirical treatment.

PIP: This study evaluated wide-needle (19-gauge) aspiration in the diagnosis of tuberculous lymphadenitis. 304 patients presenting to 1 surgeon for diagnostic surgical biopsy of a peripheral lymph node during 1989 and 1990 at the Department of Surgery, University Teaching Hospital, Lusaka, Zambia, were involved in this prospective study in which wide-needle aspiration routinely preceded open surgical biopsy. Histology and mycobacterial culture of the surgically biopsied lymph node, HIV-1 serology, successful aspiration of material, naked-eye appearance of aspirate, and presence of acid-fast bacilli and/or microscopic caseation in the aspirate were the main outcome measures. 188 of 304 (61.8%) patients had histologically and/or culture-proven tuberculous lymphadenitis, of whom 155 of 183 (84.7%) tested HIV-1 seropositive. Material was successfully aspirated from 190 of 188 (95.7%) patients with proven tuberculous lymphadenitis. Macroscopic caseation, diagnosable on naked-eye examination alone of the aspirate, was present in 49 of 120 (40.8%) consecutive aspirates from tuberculous nodes. Acid-fast bacilli and/or microscopic caseation were seen in 116 of 155 (74.8%) aspirates from tuberculous nodes for which smears stained by both Ziehl-Nielsen and hematoxylin and eosin were available. It is recommended that all patients with suspected tuberculous lymphadenitis in Africa undergo wide-needle aspiration before surgical biopsy or empirical treatment.

The impact of HIV on infectiousness of pulmonary tuberculosis: a community study in Zambia.

OBJECTIVE: To examine the impact of HIV on infectiousness of pulmonary tuberculosis (TB). DESIGN: A cross-sectional tuberculin survey carried out among household contacts of HIV-1-positive and negative patients with bacteriologically confirmed pulmonary TB. Contacts were also examined for active TB. SETTING: Index cases were recruited from patients attending the University Teaching Hospital in Lusaka, Zambia and household contacts were examined during visits to their homes within Lusaka. PATIENTS, PARTICIPANTS: A total of 207 contacts of 43 HIV-positive patients, and 141 contacts of 28 HIV-negative patients with pulmonary TB were examined. MAIN OUTCOME MEASURES: Proportion of contacts of HIV-positive and negative index cases with a positive tuberculin response (diameter of induration > or = 5 mm to a dose of 2 tuberculin units). RESULTS: Fifty-two per cent of contacts of HIV-positive pulmonary TB patients had a positive tuberculin response compared with 71% of contacts of HIV-negative patients (odds ratio, 0.43; 95% CI, 0.26-0.72; P < 0.001). This difference persisted after allowing for between-household variations in the tuberculin response. Tuberculin response in the contact was related to age of contact, intimacy with the index case and crowding in the household. However, the effect of HIV status of the index case was not confounded by these variables. Tuberculin response in the contact was also related to the number of bacilli seen in the sputum smear of the index case which partially explained the effect of HIV status of the index case. Active TB was diagnosed in 4% of contacts of HIV-positive and 3% of contacts of HIV-negative cases, respectively (P = 0.8). CONCLUSIONS: HIV-positive patients with pulmonary TB may be less infectious than their HIV-negative counterparts and this may partly be explained by lower bacillary load in the sputum.

PIP: Between April and December 1989, the chest clinic of the University Teaching Hospital in Lusaka, Zambia, confirmed pulmonary tuberculosis (TB) in 141 adults, 95 (67%) of whom were HIV-1 seropositive. Health workers made home visits to 71 of the index cases (43 HIV-1 positive and 28 HIV-1 negative) to learn whether the 348 household members would also develop TB, thus allowing researchers to determine the effect of HIV on infectiousness of TB. Contacts of HIV-1 positive patients developed TB at a lower rate than did those of HIV-1 negative patients (52% vs. 71%; odds ratio [OR] = 0.43; p .001). This difference continued even after controlling for between-household variations, indicating that confounding variables did not account for the difference. Age of contact, intimacy with the index case, and crowding in the household were associated with the tuberculin response in the contact, but they did not confound the effect of HIV status. Tuberculin response in the contact was associated with the number of bacilli in the sputum smear (crude OR = 3.13; p = .013, and adjusted OR =1.84; p = .28), suggesting that the number of bacilli somewhat explained the difference in infectiousness between HIV-1 positive and HIV-1 negative patients. 12 contacts (8 of HIV-positive cases and 4 of HIV-negative cases) developed active TB after the TB diagnosis in the index case. These findings clearly demonstrated that infection with Mycobacterium tuberculosis was less likely in household members of HIV-1 positive cases than in those of HIV-1 negative cases. The lower bacillary load in the sputum in HIV- 1 cases may have accounted somewhat for the lower infectiousness of pulmonary TB.

HIV-1-related pleural tuberculosis: elevated production of IFN-gamma, but failure of immunity to Mycobacterium tuberculosis.

BACKGROUND: Pleural tuberculosis can resolve spontaneously, suggesting that the inflammatory process may represent a protective immune response. However, pleural tuberculosis is strongly associated with HIV infection. It has been suggested that cell-mediated immune responses may be reduced, and direct bacterial invasion may have a role in pathogenesis, in HIV-positive cases. To test this hypothesis, we compared production of the pro-inflammatory cytokines, interferon (IFN)-gamma and tumour necrosis factor(TNF)-alpha, production of the immunosuppressive cytokine, interleukin (IL)-10, and mycobacterial culture positivity, in HIV-negative and HIV-positive patients with pleural tuberculosis. METHODS: Cytokine levels were measured in serum and pleural fluid, and in supernatants of blood and pleural fluid stimulated in vitro using mycobacterial antigens. Intracellular IFN-gamma and TNF-alpha production was measured after stimulation with phorbol myristate acetate and ionomycin in vitro. RESULTS: IFN-gamma was strikingly elevated in serum and pleural fluid in HIV-positive, compared to HIV-negative subjects (P < or = 0.02). TNF-alpha was elevated, but this was not statistically significant. IL-10 levels were higher in serum (P < 0.001), but similar in pleural fluid. IFN-gamma responses to soluble mycobacterial antigen in vitro were reduced in peripheral blood (P = 0.006), but not pleural fluid, of HIV-positive subjects. Intracellular cytokine staining suggested that CD8+ T cells were a major source of IFN-gamma in HIV-positive subjects. The proportion of subjects with a positive culture for Mycobacterium tuberculosis from pleural fluid was higher in the HIV-positive group. CONCLUSIONS: HIV-positive patients with pleural tuberculosis show elevated production of IFN-gamma, for which CD8+ T cells may be a major source. Mycobacterium tuberculosis can proliferate despite high levels of pro-inflammatory cytokines.

Twice weekly tuberculosis preventive therapy in HIV infection in Zambia.

BACKGROUND: A randomized double-blind placebo-controlled trial was conducted to estimate the efficacy of preventive therapy for tuberculosis (TB) in HIV-infected adults in Lusaka, Zambia. The main outcome measures were the incidence of TB, mortality and adverse drug reactions. METHODS: During a 2 year period, 1053 HIV-positive individuals without evidence of clinical TB were randomly assigned to receive 6 months of isoniazid twice a week (H), or 3 months of rifampicin twice a week (R) plus pyrazinamide (Z), or a placebo. Therapy was taken twice a week and was self administered. Subjects presenting with symptoms during the follow-up period were investigated for TB. RESULTS: The 1053 subjects in the study were followed up for a total of 1631 person-years (median = 1.8 years). Twenty-nine subjects were taken off treatment as a result of adverse drug reactions. A total of 96 cases of TB/probable TB (59 TB and 37 probable TB) were diagnosed during the study period and 185 deaths were reported. One hundred and fifteen subjects (11%) did not return to the study clinic at any time after enrolment. The incidence of TB was lower in those subjects on preventive therapy (H and RZ groups combined) compared with those on placebo (rate ratio = 0.60, 95% CI: 0.36-1.01, P = 0.057), as was the incidence of TB/probable TB (rate ratio = 0.60, 95% CI: 0.40-0.89, P = 0.013). The effect of preventive therapy was greater in those with a tuberculin skin test (TST) of 5 mm or greater, in those with a lymphocyte count of 2x10(9)/l or higher, and in those with haemoglobin of 10 g/dl or higher. There was no difference in mortality rates between the preventive therapy and placebo groups. The effect of preventive therapy declined after the first year of the study so that by 18 months the rates of TB in the treated groups were similar to that in the placebo group. CONCLUSION: This study has demonstrated that preventive therapy with either twice weekly isoniazid for 6 months or a combination of rifampicin and pyrazinamide for 3 months reduced the incidence of TB in HIV-infected persons in Zambia. No effect was observed on mortality. The effect was greatest in persons who had a positive TST or a lymphocyte count of 2x10(9)/l or greater, indicating that preventive therapy may be more effective in people with less advanced immunosuppression. The limited duration of the protective effect reported in this study raises the question of the need for lifelong preventive therapy or re-prophylaxis.

The course of chronic pain in the community: results of a 4-year follow-up study.

Little is known about the course of chronic pain in the community. Such information is needed for the prevention and management of chronic pain. We undertook a 4-year follow-up study of 2184 individuals living in Grampian, UK to describe patterns and predictors of change in chronic pain over time. In October 2000, participants completed a postal questionnaire including case definition questions, the chronic pain grade questionnaire, the SF-36 and socio-demographic questions. Information from this questionnaire was compared to information collected from a similar questionnaire in 1996. A response rate of 83% was achieved for the follow-up study. The overall prevalence of chronic pain (pain or discomfort present either all the time or on and off for 3 months or longer) increased from 45.5% at baseline to 53.8% at follow-up. Seventy-nine percent of those with chronic pain at baseline still had it at follow-up. The average annual incidence was 8.3% and the average annual recovery rate was 5.4%. Individuals in the study samples who are in lowest quartile of SF-36 domains--physical functioning, social functioning and bodily pain at baseline--were more likely to develop chronic pain at follow-up, and respondents who were retired were less likely to develop chronic pain. Individuals in the study samples in the lowest quartile of SF-36 domains, bodily pain and general health at baseline, were less likely to recover from their chronic pain, as were those aged 45-74 compared with those aged 25-34. We concluded that chronic pain is a common, persistent problem in the community with relatively high incidence and low recovery rates. The lack of association between onset or recovery from chronic pain and most traditional socio-demographic factors, highlights the need to broaden the range of factors included in studies of chronic pain aetiology.

Fluorescence labeling of bacteria for studies of intracellular pathogenesis.

Interactions between intracellular bacterial pathogens and their eukaryotic cellular hosts or targets are often studied with fluorescence-based techniques such as fluorescence microscopy and flow cytometry. We tested whether the intracellular bacterial pathogens L. monocytogenes, M. avium, M. tuberculosis, and S. typhimurium could be labeled by growth in broth containing the fluorochromes carboxy-X-rhodamine (CR), a hydrazine derivative of fluorescein (FH), and Lucifer Yellow CH (LY). Only Listeria were labeled by all three fluorochromes, Salmonella took up only FH, whereas M. avium and M. tuberculosis were labeled by FH and LY. In general, the fluorochromes did not affect bacterial growth or viability, although FH inhibited the growth of M. tuberculosis. Fluorescent Listeria and M. tuberculosis were used to demonstrate that FH- and LY-labeled bacteria were bright enough after phagocytosis by macrophages to distinguish phagocytic from nonphagocytic cells by flow cytometry. To test whether the fluorochromes might alter bacterial interactions with host cells, we measured both phagocytosis of fluorescent Listeria by macrophages and subsequent bacterial replication in these cells. In these experiments, labeled and unlabeled Listeria were phagocytosed similarly by macrophages and were not impaired in their ability to replicate within them. Thus, this method for fluorescence labeling of bacteria is useful for studying physiologic macrophage:bacteria interactions.