Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Sigve D. Holmen is active.

Publication


Featured researches published by Sigve D. Holmen.


American Journal of Tropical Medicine and Hygiene | 2011

HIV Target Cells in Schistosoma haematobium -Infected Female Genital Mucosa

Peter Mark Jourdan; Sigve D. Holmen; Svein Gunnar Gundersen; Borghild Roald; Eyrun Floerecke Kjetland

The parasite Schistosoma haematobium frequently causes genital lesions in women and could increase the risk of human immunodeficiency virus (HIV) transmission. This study quantifies the HIV target cells in schistosome-infected female genital mucosa. Cervicovaginal biopsies with and without schistosomiasis were immunostained for quantification of CD4(+) T lymphocytes (CD3, CD8), macrophages (CD68), and dendritic Langerhans cells (S100 protein). We found significantly higher densities of genital mucosal CD4(+) T lymphocytes and macrophages surrounding schistosome ova compared with cervicovaginal mucosa without ova (P = 0.034 and P = 0.018, respectively). We found no increased density of Langerhans cells (P = 0.25). This study indicates that S. haematobium may significantly increase the density of HIV target cells (CD4(+) T lymphocytes and macrophages) in the female genitals, creating a beneficial setting for HIV transmission. Further studies are needed to confirm these findings and to evaluate the effect of anti-schistosomal treatment on female genital schistosomiasis.


PLOS ONE | 2014

Effect of female genital schistosomiasis and anti-schistosomal treatment on monocytes, CD4+ T-cells and CCR5 expression in the female genital tract.

Elisabeth Kleppa; Veron Ramsuran; Siphosenkosi Gift Zulu; Gunn Hege Karlsen; Alfred Bere; Jo-Ann S. Passmore; Patricia D. Ndhlovu; Kristine Lillebø; Sigve D. Holmen; Mathias Onsrud; Svein Gunnar Gundersen; Myra Taylor; Eyrun Floerecke Kjetland; Thumbi Ndung’u

Background Schistosoma haematobium is a waterborne parasite that may cause female genital schistosomiasis (FGS), characterized by genital mucosal lesions. There is clinical and epidemiological evidence for a relationship between FGS and HIV. We investigated the impact of FGS on HIV target cell density and expression of the HIV co-receptor CCR5 in blood and cervical cytobrush samples. Furthermore we evaluated the effect of anti-schistosomal treatment on these cell populations. Design The study followed a case-control design with post treatment follow-up, nested in an on-going field study on FGS. Methods Blood and cervical cytobrush samples were collected from FGS negative and positive women for flow cytometry analyses. Urine samples were investigated for schistosome ova by microscopy and polymerase chain reaction (PCR). Results FGS was associated with a higher frequency of CD14+ cells (monocytes) in blood (11.5% in FGS+ vs. 2.2% in FGS-, p = 0.042). Frequencies of CD4+ cells expressing CCR5 were higher in blood samples from FGS+ than from FGS- women (4.7% vs. 1.5%, p = 0.018). The CD14+ cell population decreased significantly in both compartments after anti-schistosomal treatment (p = 0.043). Although the frequency of CD4+ cells did not change after treatment, frequencies of CCR5 expression by CD4+ cells decreased significantly in both compartments (from 3.4% to 0.5% in blood, p = 0.036; and from 42.4% to 5.6% in genital samples, p = 0.025). Conclusions The results support the hypothesis that FGS may increase the risk of HIV acquisition, not only through damage of the mucosal epithelial barrier, but also by affecting HIV target cell populations, and that anti-schistosomal treatment can modify this.


International Journal of Gynecology & Obstetrics | 2014

Classification of the lesions observed in female genital schistosomiasis

Eyrun Floerecke Kjetland; Hanne M. Norseth; Myra Taylor; Kristine Lillebø; Elisabeth Kleppa; Sigve D. Holmen; Asmeret Andebirhan; Tsion H. Yohannes; Svein Gunnar Gundersen; Birgitte J. Vennervald; Jayanthilall S. Bagratee; Mathias Onsrud; Peter Leutscher

Authors version of an article in the journal: International Journal of Gynecology and Obstetrics. Also available from the publisher at: http://dx.doi.org/10.1016/j.ijgo.2014.07.014


PLOS Neglected Tropical Diseases | 2014

The colposcopic atlas of schistosomiasis in the lower female genital tract based on studies in Malawi, Zimbabwe, Madagascar and South Africa

Hanne M. Norseth; Patricia D. Ndhlovu; Elisabeth Kleppa; Bodo Sahondra Randrianasolo; Peter Mark Jourdan; Borghild Roald; Sigve D. Holmen; Svein Gunnar Gundersen; Jayanthilall S. Bagratee; Mathias Onsrud; Eyrun Floerecke Kjetland

Background Schistosoma (S.) haematobium is a neglected tropical disease which may affect any part of the genital tract in women. Female genital schistosomiasis (FGS) may cause abnormal vaginal discharge, contact bleeding, genital tumours, ectopic pregnancies and increased susceptibility to HIV. Symptoms may mimic those typical of sexually transmitted infections (STIs) and women with genital schistosomiasis may be incorrectly diagnosed. An expert consensus meeting suggested that the following findings by visual inspection should serve as proxy indicators for the diagnosis of schistosomiasis of the lower genital tract in women from S. haematobium endemic areas: sandy patches appearing as (1) single or clustered grains or (2) sandy patches appearing as homogenous, yellow areas, or (3) rubbery papules. In this atlas we aim to provide an overview of the genital mucosal manifestations of schistosomiasis in women. Methodology/Principal findings Photocolposcopic images were captured from women, between 1994 and 2012 in four different study sites endemic for S. haematobium in Malawi, Zimbabwe, South Africa and Madagascar. Images and specimens were sampled from sexually active women between 15 and 49 years of age. Colposcopic images of other diseases are included for differential diagnostic purposes. Significance This is the first atlas to present the clinical manifestations of schistosomiasis in the lower female genital tract. It will be freely available for online use, downloadable as a presentation and for print. It could be used for training purposes, further research, and in clinical practice.


Sexually Transmitted Infections | 2015

Cervical ectopy: associations with sexually transmitted infections and HIV. A cross-sectional study of high school students in rural South Africa

Elisabeth Kleppa; Sigve D. Holmen; Kristine Lillebø; Eyrun Floerecke Kjetland; Svein Gunnar Gundersen; Myra Taylor; Prashini Moodley; Mathias Onsrud

Objectives It has been hypothesised that ectopy may be associated with increased susceptibility to sexually transmitted infections (STIs). In this cross-sectional study, we wanted to explore the association between STIs (including HIV) and cervical ectopy. Methods We included 700 sexually active young women attending randomly selected high schools in a rural district in KwaZulu-Natal, South Africa. The district is endemic of HIV and has a high prevalence of STIs. We did computer-assisted measurements of the ectocervical area covered by columnar epithelium (ectopy) in colposcopic images and STI analyses on cervicovaginal lavage and serum samples. All participating women answered a questionnaire about sexual behaviour and use of contraceptives. Results The mean age was 19.1 years. Ectopy was found in 27.2%, HIV in 27.8%, chlamydia in 25.3% and gonorrhoea in 15.6%. We found that age, parity, chlamydia and gonorrhoea, years since menarche, years since sexual debut and number of sexual partners were associated with ectopy. In multivariate analysis with chlamydia infection as the dependent variable, women with ectopy had increased odds of having chlamydia infection (adjusted OR 1.78, p=0.033). In women under 19 years of age, we found twofold higher odds of being HIV-positive for those with ectopy (OR 2.19, p=0.014). Conclusions In conclusion, cervical ectopy is associated with Chlamydia trachomatis infection and HIV in the youngest women.


PLOS ONE | 2015

Schistosoma haematobium Infection and CD4+ T-Cell Levels: A Cross-Sectional Study of Young South African Women

Elisabeth Kleppa; Kari F. Klinge; Hashini Nilushika Galaphaththi-Arachchige; Sigve D. Holmen; Kristine Lillebø; Mathias Onsrud; Svein Gunnar Gundersen; Myra Taylor; Patricia D. Ndhlovu; Eyrun Floerecke Kjetland

Schistosoma (S.) haematobium causes urogenital schistosomiasis and has been hypothesized to adversely impact HIV transmission and progression. On the other hand it has been hypothesized that HIV could influence the manifestations of schistosomiasis. In this cross-sectional study, we explored the association between urogenital S. haematobium infection and CD4 cell counts in 792 female high-school students from randomly selected schools in rural KwaZulu-Natal, South Africa. We also investigated the association between low CD4 cell counts in HIV positive women and the number of excreted schistosome eggs in urine. Sixteen percent were HIV positive and 31% had signs of urogenital schistosomiasis (as determined by genital sandy patches and / or abnormal blood vessels on ectocervix / vagina by colposcopy or presence of eggs in urine). After stratifying for HIV status, participants with and without urogenital schistosomiasis had similar CD4 cell counts. Furthermore, there was no significant difference in prevalence of urogenital schistosomiasis in HIV positive women with low and high CD4 cell counts. There was no significant difference in the number of eggs excreted in urine when comparing HIV positive and HIV negative women. Our findings indicate that urogenital schistosomiasis do not influence the number of circulating CD4 cells.


American Journal of Tropical Medicine and Hygiene | 2015

The First Step Toward Diagnosing Female Genital Schistosomiasis by Computer Image Analysis

Sigve D. Holmen; Elisabeth Kleppa; Kristine Lillebø; Pavitra Pillay; Lisette van Lieshout; Myra Taylor; Fritz Albregtsen; Birgitte J. Vennervald; Mathias Onsrud; Eyrun Floerecke Kjetland

Schistosoma haematobium causes female genital schistosomiasis (FGS), which is a poverty-related disease in sub-Saharan Africa. Furthermore, it is co-endemic with human immunodeficiency virus (HIV), and biopsies from genital lesions may expose the individual to increased risk of HIV infection. However, microscopy of urine and hematuria are nonspecific and insensitive predictors of FGS and gynecological investigation requires extensive training. Safe and affordable diagnostic methods are needed. We explore a novel method of diagnosing FGS using computer color analysis of colposcopic images. In a cross-sectional study on young women in an endemic area, we found strong associations between the output from the computer color analysis and both clinical diagnosis (odds ratio [OR] = 5.97, P < 0.001) and urine microscopy for schistosomiasis (OR = 3.52, P = 0.004). Finally, using latent class statistics, we estimate that the computer color analysis yields a sensitivity of 80.5% and a specificity of 66.2% for the diagnosis of FGS.


PLOS ONE | 2015

Sustained Toll-Like Receptor 9 Activation Promotes Systemic and Cardiac Inflammation, and Aggravates Diastolic Heart Failure in SERCA2a KO Mice.

Yangchen Dhondup; Ivar Sjaastad; Helge Scott; Øystein Sandanger; Lili Zhang; Solveig Bjærum Haugstad; Jan Magnus Aronsen; Trine Ranheim; Sigve D. Holmen; Katrine Alfsnes; Muhammad Shakil Ahmed; Håvard Attramadal; Lars Gullestad; Pål Aukrust; Geir Christensen; Arne Yndestad; Leif Erik Vinge

Aim Cardiac inflammation is important in the pathogenesis of heart failure. However, the consequence of systemic inflammation on concomitant established heart failure, and in particular diastolic heart failure, is less explored. Here we investigated the impact of systemic inflammation, caused by sustained Toll-like receptor 9 activation, on established diastolic heart failure. Methods and Results Diastolic heart failure was established in 8–10 week old cardiomyocyte specific, inducible SERCA2a knock out (i.e., SERCA2a KO) C57Bl/6J mice. Four weeks after conditional KO, mice were randomized to receive Toll-like receptor 9 agonist (CpG B; 2μg/g body weight) or PBS every third day. After additional four weeks, echocardiography, phase contrast magnetic resonance imaging, histology, flow cytometry, and cardiac RNA analyses were performed. A subgroup was followed, registering morbidity and death. Non-heart failure control groups treated with CpG B or PBS served as controls. Our main findings were: (i) Toll-like receptor 9 activation (CpG B) reduced life expectancy in SERCA2a KO mice compared to PBS treated SERCA2a KO mice. (ii) Diastolic function was lower in SERCA2a KO mice with Toll-like receptor 9 activation. (iii) Toll-like receptor 9 stimulated SERCA2a KO mice also had increased cardiac and systemic inflammation. Conclusion Sustained activation of Toll-like receptor 9 causes cardiac and systemic inflammation, and deterioration of SERCA2a depletion-mediated diastolic heart failure.


Medical Engineering & Physics | 2015

Colourimetric image analysis as a diagnostic tool in female genital schistosomiasis

Sigve D. Holmen; Eyrun Floerecke Kjetland; Myra Taylor; Elisabeth Kleppa; Kristine Lillebø; Svein Gunnar Gundersen; Mathias Onsrud; Fritz Albregtsen

Female genital schistosomiasis (FGS) is a highly prevalent waterborne disease in some of the poorest areas of sub-Saharan Africa. Reliable and affordable diagnostics are unavailable. We explored colourimetric image analysis to identify the characteristic, yellow lesions caused by FGS. We found that the method may yield a sensitivity of 83% and a specificity of 73% in colposcopic images. The accuracy was also explored in images of simulated inferior quality, to assess the possibility of implementing such a method in simple, electronic devices. This represents the first step towards developing a safe and affordable aid in clinical diagnosis, allowing for a point-of-care approach.


PLOS Neglected Tropical Diseases | 2016

Characteristics of Blood Vessels in Female Genital Schistosomiasis: Paving the Way for Objective Diagnostics at the Point of Care.

Sigve D. Holmen; Hashini Nilushika Galappaththi-Arachchige; Elisabeth Kleppa; Pavitra Pillay; Thajasvarie Naicker; Myra Taylor; Mathias Onsrud; Eyrun Floerecke Kjetland; Fritz Albregtsen

Background The mucosal changes associated with female genital schistosomiasis (FGS) encompass abnormal blood vessels. These have been described as circular, reticular, branched, convoluted and having uneven calibre. However, these characteristics are subjective descriptions and it has not been explored which of them are specific to FGS. Methods In colposcopic images of young women from a schistosomiasis endemic area, we performed computerised morphologic analyses of the cervical vasculature appearing on the mucosal surface. Study participants where the cervix was classified as normal served as negative controls, women with clinically diagnosed FGS and presence of typical abnormal blood vessels visible on the cervical surface served as positive cases. We also included women with cervical inflammatory conditions for reasons other than schistosomiasis. By automating morphological analyses, we explored circular configurations, vascular density, fractal dimensions and fractal lacunarity as parameters of interest. Results We found that the blood vessels typical of FGS are characterised by the presence of circular configurations (p < 0.001), increased vascular density (p = 0.015) and increased local connected fractal dimensions (p = 0.071). Using these features, we were able to correctly classify 78% of the FGS-positive cases with an accuracy of 80%. Conclusions The blood vessels typical of FGS have circular configurations, increased vascular density and increased local connected fractal dimensions. These specific morphological features could be used diagnostically. Combined with colourimetric analyses, this represents a step towards making a diagnostic tool for FGS based on computerised image analysis.

Collaboration


Dive into the Sigve D. Holmen's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Myra Taylor

University of KwaZulu-Natal

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Pavitra Pillay

Durban University of Technology

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge