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Lynch DH, Andreasen A, Maraskovsky E, Whitmore J, Miller RE, Schuh JC. Flt3 ligand induces tumor regression and antitumor immune responses in vivo. Nat Med 1997; 3:625-31. [PMID: 9176488 DOI: 10.1038/nm0697-625] [Citation(s) in RCA: 213] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Daily treatment of mice with recombinant human Flt3 ligand (huFlt3L) results in a dramatic numerical increase in the number of dendritic cells (DCs) in vivo. Since DCs are pivotal in the induction of immune responses, we tested whether Flt3L treatment of mice challenged with a syngeneic methylcholanthrene (MCA)-induced fibrosarcoma would augment the generation of effective antitumor immune responses in vivo. Flt3L treatment not only induced complete tumor regression in a significant proportion of mice, but also decreased tumor growth rate in the remaining mice. A preliminary characterization of the cellular mechanisms involved suggests that Flt3L may be important in the treatment of cancer in situ through the generation of specific antitumor immune responses.
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213 |
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Danscher G, Jensen KB, Frederickson CJ, Kemp K, Andreasen A, Juhl S, Stoltenberg M, Ravid R. Increased amount of zinc in the hippocampus and amygdala of Alzheimer's diseased brains: a proton-induced X-ray emission spectroscopic analysis of cryostat sections from autopsy material. J Neurosci Methods 1997; 76:53-9. [PMID: 9334939 DOI: 10.1016/s0165-0270(97)00079-4] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Zinc has been implicated as a contributing cause of the neuropathology of Alzheimer's disease (AD), but consensus on the zinc content of AD brains has not yet been established. In the present study, multi-element PIXE was used to measure zinc in cryostat sections of brain tissue from AD patients and from normal control subjects. Compared to their age-matched controls, the AD patients showed an increase in zinc in the hippocampal and amygdalar regions. The instrumental PIXE assays do not show whether the zinc changes are due to altered zinc in the boutons of Zinc-ENriched (ZEN) neurons, i.e., zinc ions in synaptic vesicles, or to changes in the amount of zinc tightly bound to macromolecules. We hypothesise that the increased zinc level is caused by an increase in the amount of ZEN terminals. Such an increase could be the result of a sprout of ZEN terminals in diseased areas of the brain.
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132 |
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Drewes AM, Helweg-Larsen S, Petersen P, Brennum J, Andreasen A, Poulsen LH, Jensen TS. McGill Pain Questionnaire translated into Danish: experimental and clinical findings. Clin J Pain 1993; 9:80-7. [PMID: 8358143 DOI: 10.1097/00002508-199306000-00002] [Citation(s) in RCA: 119] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To develop a methodology for translating the McGill Pain Questionnaire (MPQ) into a Danish version, and to make comparisons to studies of patients speaking other languages. DESIGN Finding suitable Danish adjectives using the same methodology as that in the original MPQ. Comparison of Danish descriptors to the words in the English version of MPQ. Survey in healthy subjects and patients with rheumatoid arthritis (RA) and fibromyalgia (F). SETTING The general public and hospital outpatients. PATIENTS A random sample of 186 healthy volunteers, 20 patients with rheumatoid arthritis and 41 patients with fibromyalgia. MAIN OUTCOME MEASURES Danish words translated as closely as possible to the descriptors in the original McGill Pain Questionnaire. A pain-assessment instrument making international pain description possible. RESULTS A Danish version of the McGill Pain Questionnaire was developed with scale values of Danish descriptors not differing more than 5 x SEM from the 'patient' words in the English version. The subdivision into classes and subclasses was respected. In the reliability experiment, the same rank values were found in 85% of subclasses. In a study using two experimental pain stimulus intensities, seven of 10 subjects obtained higher MPQ scores following the high-intensity stimulus. In the clinical study, the pain profiles of patients with RA and F in English, Italian, and Danish patients were almost the same. CONCLUSION The present methodology of translating the McGill Pain Questionnaire permits comparison of studies from English-speaking and non-English-speaking populations, thus facilitating international research exchange.
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119 |
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Doyle AM, Ross DA, Maganja K, Baisley K, Masesa C, Andreasen A, Plummer ML, Obasi AIN, Weiss HA, Kapiga S, Watson-Jones D, Changalucha J, Hayes RJ, for the MEMA kwa Vijana Trial Study Group. Long-term biological and behavioural impact of an adolescent sexual health intervention in Tanzania: follow-up survey of the community-based MEMA kwa Vijana Trial. PLoS Med 2010; 7:e1000287. [PMID: 20543994 PMCID: PMC2882431 DOI: 10.1371/journal.pmed.1000287] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 04/22/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The ability of specific behaviour-change interventions to reduce HIV infection in young people remains questionable. Since January 1999, an adolescent sexual and reproductive health (SRH) intervention has been implemented in ten randomly chosen intervention communities in rural Tanzania, within a community randomised trial (see below; NCT00248469). The intervention consisted of teacher-led, peer-assisted in-school education, youth-friendly health services, community activities, and youth condom promotion and distribution. Process evaluation in 1999-2002 showed high intervention quality and coverage. A 2001/2 intervention impact evaluation showed no impact on the primary outcomes of HIV seroincidence and herpes simplex virus type 2 (HSV-2) seroprevalence but found substantial improvements in SRH knowledge, reported attitudes, and some reported sexual behaviours. It was postulated that the impact on "upstream" knowledge, attitude, and reported behaviour outcomes seen at the 3-year follow-up would, in the longer term, lead to a reduction in HIV and HSV-2 infection rates and other biological outcomes. A further impact evaluation survey in 2007/8 ( approximately 9 years post-intervention) tested this hypothesis. METHODS AND FINDINGS This is a cross-sectional survey (June 2007 through July 2008) of 13,814 young people aged 15-30 y who had attended trial schools during the first phase of the MEMA kwa Vijana intervention trial (1999-2002). Prevalences of the primary outcomes HIV and HSV-2 were 1.8% and 25.9% in males and 4.0% and 41.4% in females, respectively. The intervention did not significantly reduce risk of HIV (males adjusted prevalence ratio [aPR] 0.91, 95%CI 0.50-1.65; females aPR 1.07, 95%CI 0.68-1.67) or HSV-2 (males aPR 0.94, 95%CI 0.77-1.15; females aPR 0.96, 95%CI 0.87-1.06). The intervention was associated with a reduction in the proportion of males reporting more than four sexual partners in their lifetime (aPR 0.87, 95%CI 0.78-0.97) and an increase in reported condom use at last sex with a non-regular partner among females (aPR 1.34, 95%CI 1.07-1.69). There was a clear and consistent beneficial impact on knowledge, but no significant impact on reported attitudes to sexual risk, reported pregnancies, or other reported sexual behaviours. The study population was likely to have been, on average, at lower risk of HIV and other sexually transmitted infections compared to other rural populations, as only youth who had reached year five of primary school were eligible. CONCLUSIONS SRH knowledge can be improved and retained long-term, but this intervention had only a limited effect on reported behaviour and no significant effect on HIV/STI prevalence. Youth interventions integrated within intensive, community-wide risk reduction programmes may be more successful and should be evaluated. TRIAL REGISTRATION ClinicalTrials.gov NCT00248469
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Randomized Controlled Trial |
15 |
102 |
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Downs JA, van Dam GJ, Changalucha JM, Corstjens PLAM, Peck RN, de Dood CJ, Bang H, Andreasen A, Kalluvya SE, van Lieshout L, Johnson WD, Fitzgerald DW. Association of Schistosomiasis and HIV infection in Tanzania. Am J Trop Med Hyg 2012; 87:868-73. [PMID: 23033399 DOI: 10.4269/ajtmh.2012.12-0395] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Animal and human studies suggest that Schistosoma mansoni infection may increase risk of human immunodeficiency virus (HIV) acquisition. Therefore, we tested 345 reproductive age women in rural Tanzanian villages near Lake Victoria, where S. mansoni is hyperendemic, for sexually transmitted infections (STIs) and schistosomiasis by circulating anodic antigen (CAA) serum assay. Over one-half (54%) had an active schistosome infection; 6% were HIV-seropositive. By univariate analysis, only schistosome infection predicted HIV infection (odds ratio [OR] = 3.9, 95% confidence interval = [1.3-12.0], P = 0.015) and remained significant using multivariate analysis to control for age, STIs, and distance from the lake (OR = 6.2 [1.7-22.9], P = 0.006). HIV prevalence was higher among women with more intense schistosome infections (P = 0.005), and the median schistosome intensity was higher in HIV-infected than -uninfected women (400 versus 15 pg CAA/mL, P = 0.01). This finding suggests that S. mansoni infection may be a modifiable HIV risk factor that places millions of people worldwide at increased risk of HIV acquisition.
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Research Support, Non-U.S. Gov't |
13 |
85 |
6
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Drewes AM, Andreasen A, Jennum P, Nielsen KD. Zopiclone in the treatment of sleep abnormalities in fibromyalgia. Scand J Rheumatol 1991; 20:288-93. [PMID: 1925417 DOI: 10.3109/03009749109096802] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The clinical and polysomnographical effects of zopiclone were evaluated in 41 patients with fibromyalgia in a double blind controlled study. A significant improvement was observed regarding tiredness during the day and subjective sleep complaints, but no effects on pain or stiffness were observed. The sleep structure remained unchanged during treatment. Zopiclone seems to be of value in treating the sleep complaints in patients with fibromyalgia.
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Clinical Trial |
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71 |
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Drewes AM, Andreasen A, Poulsen LH. Valproate for treatment of chronic central pain after spinal cord injury. A double-blind cross-over study. PARAPLEGIA 1994; 32:565-9. [PMID: 7970862 DOI: 10.1038/sc.1994.89] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Chronic central pain is a frequent complication after spinal cord injury. Anticonvulsant drugs, among them valproate, have been recommended for treatment. In this paper we conducted a double-blind, cross-over study comparing valproate and placebo for severe chronic central pain. During the study, serum concentration of valproate, pain and side effects were registered and the dose was adjusted according to these. No significant analgesic effects of valproate could be demonstrated although serum concentration and dose reached a high level. Few studies of pain following spinal cord injury exist and we recommend that further studies be performed.
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Clinical Trial |
31 |
63 |
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Drewes AM, Andreasen A, Schrøder HD, Høgsaa B, Jennum P. Pathology of skeletal muscle in fibromyalgia: a histo-immuno-chemical and ultrastructural study. BRITISH JOURNAL OF RHEUMATOLOGY 1993; 32:479-83. [PMID: 8508284 DOI: 10.1093/rheumatology/32.6.479] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The value of muscle biopsy in fibromyalgia is still questioned. In this study we obtained 50 quadriceps biopsies from 20 patients and compared them blindly to 10 biopsies from five normal controls. Using light microscopy, histochemical and immunoenzymatic methods we found no definite evidence of muscle disease. Nevertheless, we subjected biopsies from nine of the patients and five other controls for further ultrastructural evaluations and demonstrated pathologic findings e.g. empty sleeves of basement membrane, many lipofuschin bodies and other degenerative changes. We conclude that ultrastructural evaluation cannot yet be used for diagnostic purposes, but the negative findings with light microscopy, including histochemical and immunoenzymatic techniques, might be of importance in evaluating difficult cases.
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32 |
59 |
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Andreasen A, Drewes AM, Assentoft JE, Larsen NE. Computer-assisted alignment of standard serial sections without use of artificial landmarks. A practical approach to the utilization of incomplete information in 3-D reconstruction of the hippocampal region. J Neurosci Methods 1992; 45:199-207. [PMID: 1294853 DOI: 10.1016/0165-0270(92)90077-q] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
An algorithm for the alignment of stained serial sections without the support of artificial landmarks is described. Four-hundred-thirty serial sections of the rabbit hippocampal region were digitized, and computer-based alignment was performed without use of artificial markers, resulting in a consistent matrix. Following proper filtration, artificial sections were cut through the matrix. In a second experiment every second image was deleted and reconstructed by interpolation with a minor loss of biological information. In a third experiment every second image was deleted and the rest of the images were 'disordered', realigned and the missing planes reconstructed by interpolation. Under these circumstances the matrix was reconstructed with some loss of information. These results may widen the limits of 3-dimensional (3-D) reconstruction, as routine histological preparations normally include only every second or every third section without artificial landmarks.
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48 |
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Sørensen JC, Mattsson B, Andreasen A, Johansson BB. Rapid disappearance of zinc positive terminals in focal brain ischemia. Brain Res 1998; 812:265-9. [PMID: 9813362 DOI: 10.1016/s0006-8993(98)00943-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The study was undertaken to determine if the levels of vesicular zinc in neuronal terminals would decrease in response to focal brain ischemia. The middle cerebral artery was occluded distal to the striatal branches in male spontaneously hypertensive rats. At 7, 15, 30, 45, 60, 90, 120 min; 3, 6, 12, 24, 48 h and 7 days later the animals were sacrificed and the brains were stained for zinc-sulfides, cell bodies and AChE-positive cholinergic fibers. The density of zinc positive terminals significantly decreased in the neocortical ischemic zone 7 min after middle cerebral artery occlusion (MCAO). In the neocortical layers II and III most zinc positive neuronal terminals disappeared at 7 min after MCAO whereas the zinc positive terminals in layers V and VI remained positive at least 2 h. Beginning at 1 h after MCAO and progressing to 24 h a significant decrease in the density of zinc positive terminals was observed in the dorsolateral striatum, and ventrobasal thalamic nucleus, both major projection areas of the sensorimotor cortex. The disappearance of zinc positive neuronal terminals in the ischemic neocortex and related areas, is most likely due to a neuronal release of vesicular zinc in response to hypoxia. The high extracellular concentration of zinc is thought to be both neuroprotective by blocking the NMDA receptor and neurotoxic by activating neuronal influx of Ca2+ through voltage gated calcium channels. It seems evident that the latter effect of zinc is contributing to the neuronal death in focal brain ischemia.
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Sow PS, Watson-Jones D, Kiviat N, Changalucha J, Mbaye KD, Brown J, Bousso K, Kavishe B, Andreasen A, Toure M, Kapiga S, Mayaud P, Hayes R, Lebacq M, Herazeh M, Thomas F, Descamps D. Safety and immunogenicity of human papillomavirus-16/18 AS04-adjuvanted vaccine: a randomized trial in 10-25-year-old HIV-Seronegative African girls and young women. J Infect Dis 2012; 207:1753-63. [PMID: 23242542 PMCID: PMC3636781 DOI: 10.1093/infdis/jis619] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Background. Cervical cancer is a major public health problem for women in sub-Saharan Africa. Availability of a human papillomavirus (HPV) vaccine could have an important public health impact. Methods. In this phase IIIb, double-blind, randomized, placebo-controlled, multicenter trial (NCT00481767), healthy African girls and young women seronegative for human immunodeficiency virus (HIV) were stratified by age (10–14 or 15–25 years) and randomized (2:1) to receive either HPV-16/18 AS04-adjuvanted vaccine (n = 450) or placebo (n = 226) at 0, 1, and 6 months. The primary objective was to evaluate HPV-16/18 antibody responses at month 7. Seropositivity rates and corresponding geometric mean titers (GMTs) were measured by enzyme-linked immunosorbent assay. Results. In the according-to-protocol analysis at month 7, 100% of initially seronegative participants in the vaccine group were seropositive for both anti–HPV-16 and anti–HPV-18 antibodies (n = 130 and n = 128 for 10–14-year-olds, respectively; n = 190 and n = 212 for 15–25-year-olds). GMTs for HPV-16 and HPV-18 were higher in 10–14-year-olds (18 423 [95% confidence interval, 16 185–20 970] and 6487 [5590–7529] enzyme-linked immunosorbent assay units (EU)/mL, respectively) than in 15–25-year-olds (10 683 [9567–11 930] and 3743 [3400–4120] EU/mL, respectively). Seropositivity was maintained at month 12. No participant withdrew owing to adverse events. No vaccine-related serious adverse events were reported. Conclusions. The HPV-16/18 AS04-adjuvanted vaccine was highly immunogenic and had a clinically acceptable safety profile when administered to healthy HIV-seronegative African girls and young women.
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Research Support, Non-U.S. Gov't |
13 |
47 |
12
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Hawkes S, Collumbien M, Platt L, Lalji N, Rizvi N, Andreasen A, Chow J, Muzaffar R, ur-Rehman H, Siddiqui N, Hasan S, Bokhari A. HIV and other sexually transmitted infections among men, transgenders and women selling sex in two cities in Pakistan: a cross-sectional prevalence survey. Sex Transm Infect 2009; 85 Suppl 2:ii8-16. [PMID: 19307351 DOI: 10.1136/sti.2008.033910] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES The extent and possibilities of spread of the HIV epidemic are not fully understood in Pakistan. A survey was conducted among men, women and transgender populations selling sex in Rawalpindi (Punjab) and Abbottabad (North West Frontier Province) in order to inform evidence-based programme planning. METHODS A cross-sectional survey was performed with participants recruited through respondent-driven sampling. Male and transgender sex workers were analysed in three gender groups; women were analysed as one group. Behavioural surveys were conducted and clinical specimens collected. Laboratory tests looked for evidence of acute infection (gonorrhoea, Chlamydia, syphilis, Trichomonas) and infection over the lifetime (HIV, herpes simplex virus-2, syphilis). Predictors of infection were explored using univariable and multivariable logistic regression. RESULTS The prevalence of HIV was low in 917 male and transgender sex workers and absent in 533 female sex workers in the study. High levels of current sexually transmitted infections were found, predominantly among transgender sex workers. Risk behaviours were common and knowledge of HIV was extremely low. Multivariable analysis found a large number of factors associated with higher levels of infection, including experience of forced first sex. Protection against risk was low, but those sex workers who reported using condoms at last sex had lower rates of infection. CONCLUSIONS The HIV epidemic is currently in its early stages among people who sell sex, but there may be potential for a much greater spread given the levels of other sexually transmitted infections found and the concomitant low levels of both protective knowledge and risk-reducing behaviours. Action is needed now to avert an epidemic. Framing interventions by upholding the recognition and protection of human rights is vital.
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Research Support, Non-U.S. Gov't |
16 |
46 |
13
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Francis SC, Hou Y, Baisley K, van de Wijgert J, Watson-Jones D, Ao TT, Herrera C, Maganja K, Andreasen A, Kapiga S, Coulton GR, Hayes RJ, Shattock RJ. Immune Activation in the Female Genital Tract: Expression Profiles of Soluble Proteins in Women at High Risk for HIV Infection. PLoS One 2016; 11:e0143109. [PMID: 26814891 PMCID: PMC4729472 DOI: 10.1371/journal.pone.0143109] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 10/30/2015] [Indexed: 01/20/2023] Open
Abstract
Soluble cervicovaginal biomarkers of inflammation, immune activation and risk of HIV acquisition are needed to reliably assess the safety of new biomedical prevention strategies including vaccines and microbicides. However, a fuller understanding of expression profiles in women at high risk for HIV infection is crucial to the effective use of these potential biomarkers in Phase 3 trial settings. We have measured 45 soluble proteins and peptides in cervicovaginal lavage samples from 100 HIV negative women at high risk for HIV infection. Women were followed over one menstrual cycle to investigate modulation by hormonal contraception, menstrual cycle phase, recent sexual exposure and intravaginal practices. Women using injectable DMPA had increased concentration of several soluble proteins of the innate and adaptive immune system, including IL-1α, IL-1β, IL-2, MIP-1β, IP-10, IL-8, TGF-β, HBD4, IgA, IgG1, and IgG2. Women using combined oral contraceptives had a similar signature. There were differences in concentrations among samples from post-ovulation compared to pre-ovulation, notably increased immunoglobulins. Increased prostate-specific antigen, indicative of recent sexual exposure, was correlated with increased IL-6, MCP-1, and SLPI, and decreased GM-CSF and HBD3. The identified signature profiles may prove critical in evaluating the potential safety and impact on risk of HIV acquisition of different biomedical intervention strategies.
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research-article |
9 |
45 |
14
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Watson-Jones D, Baisley K, Brown J, Kavishe B, Andreasen A, Changalucha J, Mayaud P, Kapiga S, Gumodoka B, Hayes RJ, de Sanjosé S. High prevalence and incidence of human papillomavirus in a cohort of healthy young African female subjects. Sex Transm Infect 2013; 89:358-365. [PMID: 23486859 PMCID: PMC3717757 DOI: 10.1136/sextrans-2012-050685] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 02/14/2013] [Accepted: 02/17/2013] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVES We measured the prevalence and incidence of human papillomavirus (HPV) infection in young female subjects recruited for a safety and immunogenicity trial of the bivalent HPV-16/18 vaccine in Tanzania. METHODS Healthy HIV negative female subjects aged 10-25 years were enrolled and randomised (2:1) to receive HPV-16/18 vaccine or placebo (Al(OH)3 control). At enrolment, if sexually active, genital specimens were collected for HPV DNA, other reproductive tract infections and cervical cytology. Subjects were followed to 12 months when HPV testing was repeated. RESULTS In total 334 participants were enrolled; 221 and 113 in vaccine and control arms, respectively. At enrolment, 74% of 142 sexually active subjects had HPV infection of whom 69% had >1 genotype. Prevalent infections were HPV-45 (16%), HPV-53 (14%), HPV-16 (13%) and HPV-58 (13%). Only age was associated with prevalent HPV infection at enrolment. Among 23 girls who reported age at first sex as 1 year younger than their current age, 15 (65.2%) had HPV infection. Of 187 genotype-specific infections at enrolment, 51 (27%) were present at 12 months. Overall, 67% of 97 sexually active participants with results at enrolment and 12 months had a new HPV genotype at follow-up. Among HPV uninfected female subjects at enrolment, the incidence of any HPV infection was 76 per 100 person-years. CONCLUSIONS Among young women in Tanzania, HPV is highly prevalent and acquired soon after sexual debut. Early HPV vaccination is highly recommended in this population.
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Clinical Trial, Phase III |
12 |
42 |
15
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Francis SC, Ao TT, Vanobberghen FM, Chilongani J, Hashim R, Andreasen A, Watson-Jones D, Changalucha J, Kapiga S, Hayes RJ. Epidemiology of curable sexually transmitted infections among women at increased risk for HIV in northwestern Tanzania: inadequacy of syndromic management. PLoS One 2014; 9:e101221. [PMID: 25025338 PMCID: PMC4099080 DOI: 10.1371/journal.pone.0101221] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 06/04/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Curable, non-viral pathogens account for a significant burden of sexually transmitted infections (STIs), and there is established evidence that STIs increase both HIV acquisition and transmission. We investigated the prevalence, trends, and factors associated with Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Treponema pallidum, and the performance of syndromic management, among a cohort of women working in bars, hotels, and other food and recreational facilities near large-scale mines in northwestern Tanzania. METHODS HIV-negative women aged 18-44 years (N = 966) were enrolled and followed for 12 months in a microbicides feasibility study. We collected sociodemographic and behavioural data, performed clinical examinations, and tested for STIs, at enrolment and 3-monthly. Risk factors for STIs were investigated using logistic regression models with random effects. Sensitivity, specificity and predictive values of syndromic management were calculated. RESULTS At enrolment, the prevalences of C. trachomatis, N. gonorrhoeae, T. vaginalis, and high-titre active syphilis were 111/956 (12%), 42/955 (4%), 184/945 (19%) and 46/965 (5%), respectively. There were significant decreases over time for C. trachomatis and T. vaginalis (OR trend per month: 0.94 [95% CI 0.91, 0.97]; and 0.95 [0.93, 0.98], respectively; both p<0.001). The majority of these infections were not diagnosed by the corresponding syndrome; therefore, most participants were not treated at the diagnosis visit. Syndromic management was poorly predictive of laboratory-diagnosed infections. We identified a number of risk factors for STIs, including low educational level, some sexual behaviours, and ever having been pregnant. CONCLUSIONS This analysis demonstrates that the prevalences of curable STIs are high among women who work in food and recreational facilities in northwestern Tanzania. Most of these infections are missed by syndromic management. Accurate and affordable rapid-point-of-care tests and innovative interventions are needed to reduce the burden of STIs in this population which is at increased risk for HIV.
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research-article |
11 |
39 |
16
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Holm IE, Andreasen A, Danscher G, Pérez-Clausell J, Nielsen H. Quantification of vesicular zinc in the rat brain. HISTOCHEMISTRY 1988; 89:289-93. [PMID: 2457004 DOI: 10.1007/bf00493154] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
By means of the Neo-Timm method it has recently been shown that zinc is present in a fraction of the round clear synaptic vesicles of certain boutons located primarily in telencephalic structures (Pérez-Clausell and Danscher 1985). It is believed that this zinc belongs to a fraction of the total brain zinc which is histochemically active (Frederickson and Danscher 1988) in that it can be visualized by means of e.g. the Neo-Timm and selenium methods (autometallography). The present study is based on the suggestion that the autometallographically developed zinc patterns represent a histochemical quantitative expression of this fraction of the total brain zinc. The different colours of the zinc pattern reflect local variations in the concentration of zinc containing vesicles. Large boutons with a high content of stained vesicles will show up darkly because of fusion of adjoining silver grains while smaller boutons with fewer zinc containing vesicles give rise to yellow staining of various shades. We have exploited this difference in staining of pattern by applying computerized optic densitometry to light microscopic sections treated according to the Neo-Timm and the selenium methods, respectively.
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32 |
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Danscher G, Juhl S, Stoltenberg M, Krunderup B, Schrøder HD, Andreasen A. Autometallographic silver enhancement of zinc sulfide crystals created in cryostat sections from human brain biopsies: a new technique that makes it feasible to demonstrate zinc ions in tissue sections from biopsies and early autopsy material. J Histochem Cytochem 1997; 45:1503-10. [PMID: 9358852 DOI: 10.1177/002215549704501107] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We present a new technique that allows zinc ions in synaptic and secretory vesicles of biopsy and early autopsy material (< 2 hr post mortem) to be transformed to nanometer-sized zinc sulfide crystal lattices for subsequent autometallographic (AMG) development. Human brain biopsies, or other tissue samples containing zinc-enriched (ZEN) cells, are frozen in liquid nitrogen or by CO2 gas immediately after removal. The tissue blocks are cut in a cryostat and the sections placed on glass slides. The slides are transferred to an H2S exposure chamber placed in a -15 C freezer. After 1-24 hr of gas exposure the sections are removed from the chamber, fixed while thawing, and dehydrated. The sections are then exposed to an AMG developer. AMG causes silver enhancement of zinc sulfide crystal lattices created in the tissues through the H2S exposure, making them visible. It is imperative that the tissues are frozen instantaneously after removal, because loosely bound or free zinc ions start leaving their vesicular compartment soon after death. The AMG technique can, despite inadequate fixation and damage to the tissue caused by freezing, also be used to trace zinc ions at ultrastructural levels, and it is demonstrated that zinc ions in the human neocortex are located in synaptic vesicles. In the few human biopsies analyzed thus far, the light microscopic pattern created by the silver-enhanced ZEN terminals resembles that seen in the neocortex of rat brain. The technique has been applied to cryostat sections from neocortex biopsies of five individuals undergoing brain surgery. Biopsies from three patients resulted in satisfactory AMG-stained sections. Rat brains removed and frozen immediately after decapitation constituted the material on which the present technique was developed. Such material results in an almost uniform high quality of staining, and we found that unexposed sections can be stored for at least 5 months at -80 C without ensuing significant loss of AMG staining intensity.
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Platt L, Vickerman P, Collumbien M, Hasan S, Lalji N, Mayhew S, Muzaffar R, Andreasen A, Hawkes S. Prevalence of HIV, HCV and sexually transmitted infections among injecting drug users in Rawalpindi and Abbottabad, Pakistan: evidence for an emerging injection-related HIV epidemic. Sex Transm Infect 2009; 85 Suppl 2:ii17-22. [PMID: 19307346 DOI: 10.1136/sti.2008.034090] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To measure the prevalence of hepatitis C virus (HCV), HIV and sexually transmitted infections (STI) among injecting drug users (IDUs) in Rawalpindi and Abbottabad and to examine risk factors associated with HIV and HCV. METHODS Two cross-sectional surveys were performed of community-recruited IDUs with collection of clinical specimens for testing of HCV, HIV and other STIs. Behavioural data were collected through interviewer-administered questionnaires. Characteristics and risk behaviours were compared across cities. Univariate and multivariate analyses explored risk factors associated with HIV and HCV. RESULTS The prevalence of HIV was 2.6% (95% CI 0.83% to 4.5%) in Rawalpindi (n = 302) and zero in Abbottabad (n = 102). The prevalence of HCV was significantly higher in Rawalpindi at 17.3% (95% CI 13.0% to 21.6%) than in Abbottabad at 8% (95% CI 2.6% to 13.4%). The prevalence of other STIs was low in both cities, with <2% of participants having current gonorrhoea or Chlamydia and <3% with active syphilis. Injecting risk behaviours were greater in Rawalpindi. An increased risk of HCV was associated with using informal sources as a main source of new needles/syringes (OR 2.8, 95% CI 1.3 to 6.0) compared with pharmacies and a history of drug treatment (OR 3.7, 95% CI 0.9 to 11.6). Reporting symptoms of an STI was associated with decreased odds of HIV in Rawalpindi (OR 0.02, 95% CI 0.03 to 0.9). CONCLUSIONS The findings suggest recent transmission of HIV and HCV and point to the urgent need for the provision of clean needles/syringes to IDUs and a review of how needles/syringes are currently provided via healthcare establishments.
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Research Support, Non-U.S. Gov't |
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Andreasen AA, Burton MJ, Holland MJ, Polley S, Faal N, Mabey DC, Bailey RL. Chlamydia trachomatis ompA variants in trachoma: what do they tell us? PLoS Negl Trop Dis 2008; 2:e306. [PMID: 18820750 PMCID: PMC2553491 DOI: 10.1371/journal.pntd.0000306] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 09/04/2008] [Indexed: 11/22/2022] Open
Abstract
Background Trachoma, caused by Chlamydia trachomatis (Ct), is the leading infectious cause of blindness. Sequence-based analysis of the multiple strains typically present in endemic communities may be informative for epidemiology, transmission, response to treatment, and understanding the host response. Methods Conjunctival and nasal samples from a Gambian community were evaluated before and 2 months after mass azithromycin treatment. Samples were tested for Ct by Amplicor, with infection load determined by quantitative PCR (qPCR). ompA sequences were determined and their diversity analysed using frequency-based tests of neutrality. Results Ninety-five of 1,319 (7.2%) individuals from 14 villages were infected with Ct at baseline. Two genovars (A and B) and 10 distinct ompA genotypes were detected. Two genovar A variants (A1 and A2) accounted for most infections. There was an excess of rare ompA mutations, not sustained in the population. Post-treatment, 76 (5.7%) individuals had Ct infection with only three ompA genotypes present. In 12 of 14 villages, infection had cleared, while in two it increased, probably due to mass migration. Infection qPCR loads associated with infection were significantly greater for A1 than for A2. Seven individuals had concurrent ocular and nasal infection, with divergent genotypes in five. Conclusions The number of strains was substantially reduced after mass treatment. One common strain was associated with higher infection loads. Discordant genotypes in concurrent infection may indicate distinct infections at ocular and nasal sites. Population genetic analysis suggests the fleeting appearance of rare multiple ompA variants represents purifying selection rather than escape variants from immune pressure. Genotyping systems accessing extra-ompA variation may be more informative. Trachoma is an important cause of blindness resulting from transmission of the bacterium Chlamydia trachomatis. One way to understand better how this infection is transmitted and how the human immune system controls it is to study the strains of bacteria associated with infection. Comparing strains before and after treatment might help us learn if someone has a new infection or the same one as before. Identifying differences between disease-causing strains should help us understand how infection leads to disease and how the human host defences work. We chose to study variation in the chlamydial gene ompA because it determines the protein MOMP, one of the leading candidates for inclusion in a vaccine to prevent trachoma. If immunity to MOMP is important in natural trachoma infections, we would expect to find evidence of this in the way the strains varied. We did not find this, but instead found that two common strains seemed to cause different types of disease. Although their MOMPs were very slightly different, this did not really explain the differences. We conclude that methods of typing strains going beyond the ompA gene will be needed to help us understand the interaction between Chlamydia and its human host.
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Research Support, Non-U.S. Gov't |
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Kapiga SH, Ewings FM, Ao T, Chilongani J, Mongi A, Baisley K, Francis S, Andreasen A, Hashim R, Watson-Jones D, Changalucha J, Hayes R. The epidemiology of HIV and HSV-2 infections among women participating in microbicide and vaccine feasibility studies in Northern Tanzania. PLoS One 2013; 8:e68825. [PMID: 23874780 PMCID: PMC3715536 DOI: 10.1371/journal.pone.0068825] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 06/03/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES To prepare for future HIV prevention trials, we conducted prospective cohort studies among women working in food and recreational facilities in northern Tanzania. We examined the prevalence and incidence of HIV and HSV-2, and associated risk factors. METHODS Women aged 18-44 years working in food and recreational facilities were screened to determine their eligibility for the studies. Between 2008-2010, HIV-negative women were enrolled and followed for 12 months. At enrolment and 3-monthly, we collected socio-demographic and behavioural data, and performed clinical examinations for collection of biological specimens that were tested for reproductive tract infections. Risk factors for HIV and HSV-2 incidence were investigated using Poisson regression models. RESULTS We screened 2,229 and enrolled 1,378 women. The median age was 27 years (interquartile range, IQR 22, 33), and median duration working at current facility was 2 years. The prevalences of HIV at screening and HSV-2 at enrolment were 16% and 67%, respectively. Attendance at the 12-month visit was 86%. HIV and HSV-2 incidence rates were 3.7 (95% confidence interval, CI: 2.8,5.1) and 28.6 (95% CI: 23.5,35.0)/100 person-years, respectively. Women who were separated, divorced, or widowed were at increased risk of HIV (adjusted incidence rate ratio, aRR = 6.63; 95% CI: 1.97,22.2) and HSV-2 (aRR = 2.00; 95% CI: 1.15,3.47) compared with married women. Women reporting ≥3 partners in the past 3 months were at higher HIV risk compared with women with 0-1 partner (aRR = 4.75; 95% CI: 2.10,10.8), while those who had reached secondary education or above were at lower risk of HSV-2 compared with women with incomplete primary education (aRR = 0.42; 95% CI: 0.22,0.82). CONCLUSIONS HIV and HSV-2 rates remain substantially higher in this cohort than in the general population, indicating urgent need for effective interventions. These studies demonstrate the feasibility of conducting trials to test new interventions in this highly-mobile population.
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research-article |
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Andreasen A, Danscher G, Juhl S, Stoltenberg M, Revsbech NP, Jensen H, Jensen KB. Distinct differences in partial oxygen pressure at micrometer ranges in the rat hippocampal region. J Neurosci Methods 1997; 72:15-21. [PMID: 9128163 DOI: 10.1016/s0165-0270(96)00149-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A mapping at micrometer ranges of the partial oxygen pressure in the rat hippocampus was performed. The oxygen tension in the rat hippocampal region was measured using a glass oxygen microsensor in 30-microm steps along straight lines at a set of stereotactic coordinates. In the hippocampus the pattern of the oxygen tensions reflected the autometallographic zinc sulphide (AMG(ZnS)) pattern, i.e. the pattern of zinc enriched (ZEN) terminals. The highest levels of oxygen tension were recorded in the areas that are most heavily stained with the autometallographic zinc sulphide (AMG(ZnS)) method, like hilus fasciae dentatae. The zinc ions located in synaptic vesicles of the ZEN terminals can also be demonstrated by AMG silver amplification in brains from animals in vivo treated with sodium selenite. This method depends on the presence of a substantial reduction capacity of the tissues as selenite ions (SeO(2)(3)-) must to be reduced to selenide ions (Se2-) before the catalytic zinc selenide crystals can be formed. At some point, either during the transport from the infusion site to the actual target tissue or in the target tissue itself, selenium is reduced from Se(+ IV) to Se(- II). The importance of the reduction capacity of the target tissue in this process is demonstrated by the fact that areas found to have the highest concentration of zinc ions, e.g. hilus fasciae dentatae and the mossy fibres of CA3, are almost unstained after 1 h of i.p. Na2SeO3 exposure. An explanation of this phenomenon could be that the reduction process Se(+ IV) <==> Se(- II) leading to the formation of Se2- is moved to the left by the presence of oxygen, thus inhibiting the precipitation of ZnSe crystals. It is suggested that the subtle oxygen pressure pattern found in the rat hippocampus might also reflect essential biological zinc-related mechanisms vital to brain function.
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Comparative Study |
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Smit PW, van der Vlis T, Mabey D, Changalucha J, Mngara J, Clark BD, Andreasen A, Todd J, Urassa M, Zaba B, Peeling RW. The development and validation of dried blood spots for external quality assurance of syphilis serology. BMC Infect Dis 2013; 13:102. [PMID: 23442198 PMCID: PMC3586363 DOI: 10.1186/1471-2334-13-102] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 02/21/2013] [Indexed: 11/12/2022] Open
Abstract
Background Syphilis causes up to 1,500,000 congenital syphilis cases annually. These could be prevented if all pregnant women were screened, and those with syphilis treated with a single dose of penicillin before 28 weeks gestation. In recent years, rapid point-of-care tests have allowed greater access to syphilis screening, especially in rural or remote areas, but the lack of quality assurance of rapid testing has been a concern. We determined the feasibility of using dried blood spots (DBS) as specimens for quality assurance of syphilis serological assays. Methods We developed DBS extraction protocols for use with Treponema pallidum particle agglutination assay (TPPA), Treponema pallidum haemagglutination assay (TPHA) and an enzyme immunoassay (EIA) and compared the results with those using matching plasma samples from the same patient. Results Since DBS samples showed poor performance with TPHA and EIA (TPHA sensitivity was 50.5% (95% confidence interval: 39.9–61.2%) and EIA specificity was 50.4% (95% CI: 43.7–57.1%), only the DBS TPPA was used in the final evaluation. DBS TPPA showed an sensitivity of 95.5% (95% CI: 91.3–98.0%) and a specificity of 99.0% (95% CI: 98.1–99.5%) compared to TPPA using plasma samples as a reference. Conclusion DBS samples can be recommended for use with TPPA, and may be of value for external quality assurance of point-of-care syphilis testing.
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Validation Study |
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Brown J, Baisley K, Kavishe B, Changalucha J, Andreasen A, Mayaud P, Gumodoka B, Kapiga S, Hayes R, Watson-Jones D. Impact of malaria and helminth infections on immunogenicity of the human papillomavirus-16/18 AS04-adjuvanted vaccine in Tanzania. Vaccine 2014; 32:611-617. [PMID: 24291193 PMCID: PMC3898269 DOI: 10.1016/j.vaccine.2013.11.061] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/04/2013] [Accepted: 11/15/2013] [Indexed: 10/28/2022]
Abstract
BACKGROUND Endemic malaria and helminth infections in sub-Saharan Africa can act as immunological modulators and impact responses to standard immunizations. We conducted a cohort study to measure the influence of malaria and helminth infections on the immunogenicity of the bivalent HPV-16/18 vaccine. METHODS We evaluated the association between malaria and helminth infections, and HPV-16/18 antibody responses among 298 Tanzanian females aged 10-25 years enrolled in a randomized controlled trial of the HPV-16/18 vaccine. Malaria parasitaemia was diagnosed by examination of blood smears, and helminth infections were diagnosed by examination of urine and stool samples, respectively. Geometric mean antibody titres (GMT) against HPV-16/18 antibodies were measured by enzyme-linked immunosorbent assay. RESULTS Parasitic infections were common; one-third (30.4%) of participants had a helminth infection and 10.2% had malaria parasitaemia. Overall, the vaccine induced high HPV-16/18 GMTs, and there was no evidence of a reduction in HPV-16 or HPV-18 GMT at Month 7 or Month 12 follow-up visits among participants with helminths or malaria. There was some evidence that participants with malaria had increased GMTs compared to those without malaria. CONCLUSIONS The data show high HPV immunogenicity regardless of the presence of malaria and helminth infections. The mechanism and significance for the increase in GMT in those with malaria is unknown.
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Clinical Trial, Phase III |
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Cumberland P, Edwards T, Hailu G, Harding-Esch E, Andreasen A, Mabey D, Todd J. The impact of community level treatment and preventative interventions on trachoma prevalence in rural Ethiopia. Int J Epidemiol 2008; 37:549-58. [PMID: 18356196 DOI: 10.1093/ije/dyn045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The International Trachoma Initiative (ITI) trachoma control programme based on the SAFE strategy (Surgery, Antibiotics, Facial cleanliness and Environmental improvement) was implemented in 2002 in two rural Ethiopian zones, with mass delivery of azithromycin starting in 2003. We evaluate the impact of combined antibiotic and health educational interventions on active trachoma and Chlamydia trachomatis detected from ocular swabs, in children aged 3-9 years. Method Three-year follow-up cross-sectional survey was carried out in 40 rural Ethiopian communities to evaluate the programme. Households were randomly selected and all children were invited for eye examination for active trachoma. In 2005, eye swabs were taken for Polymerase Chain Reaction (PCR) detection of ocular C. trachomatis DNA. Adult knowledge and behaviour related to trachoma were assessed. RESULTS Community summarized mean prevalence, overall, was 35.6% (SD = 17.6) for active trachoma, 34.0% (18.7) for trachomatous inflammation, follicular (TF) alone and 4.3% (5.3) for PCR positivity for C. trachomatis. After adjustment, odds of active trachoma were reduced in communities receiving antibiotics and one or two educational intervention components (OR = 0.35, 95% CI: 0.13-0.89 or OR = 0.31, 0.11-0.89, respectively). The odds of being PCR positive were lower in these intervention arms, compared with control (OR = 0.20, 0.06-0.62 and OR = 0.07, 0.02-0.30, respectively). Knowledge of treatment and preventative methods were reported with much higher frequency, compared with baseline. CONCLUSIONS Trachoma remains a public health problem in Ethiopia. Antibiotic administration remains the most effective intervention but community-based health education programmes can impact, to additionally reduce prevalence of C. trachomatis.
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Research Support, Non-U.S. Gov't |
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Stoltenberg M, Sørensen MB, Danscher G, Juhl S, Andreasen A, Ernst E. Autometallographic demonstration of zinc ions in rat sperm cells. Mol Hum Reprod 1997; 3:763-7. [PMID: 9358001 DOI: 10.1093/molehr/3.9.763] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
An in-vitro technique for autometallographic (AMG) demonstration of chelatable zinc in electroejaculated sperm cells and spermatozoa from the epididymis is presented and the localization of zinc ions in rat spermatozoa is described. Sperm cells from caput epididymis showed zinc staining in all parts of the tail and a sparse, dispersed staining in the acrosome. Spermatozoa from cauda epididymis showed heavy staining in the acrosome but no staining in the tail, or post-acrosomal part of the sperm head. This distinct acrosomal AMG staining was also found in ejaculated spermatozoa, but additionally a segmentation of the tail was seen based on differences in staining intensity. The membrane penetrating chelator diethyldithiocarbamate (DEDTC) was found to block the AMG staining whereas calcium-EDTA, known not to pass through cell membranes, did not influence the staining, proving that the detected zinc ions are intracellularly located. Two different approaches for demonstrating the presence of a chelatable zinc pool at electron microscope levels are presented, and the ultrastructural presence of AMG grains located in the acrosome and in the mitochondria of the midpiece is demonstrated. It is postulated that an exchange of zinc ions takes place between the epididymal epithelium and the sperm cells as they pass along the epididymal duct.
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