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Biomedical subjects

Henry J C de Vries

Publications and source records attributed to Henry J C de Vries.

9 recordsLinked to original sources
PubMed2006

Patients' preferences regarding the timing of highly active antiretroviral therapy initiation for chronic asymptomatic HIV-1 infection.

OBJECTIVE: In patients with a chronic asymptomatic HIV-1 infection and >200 CD4+ T-cells/microl, the optimal timing of highly active antiretroviral therapy (HAART) initiation is unclear. It involves a trade-off between a potentially reduced risk of mortality, when started earlier in the course of infection, and an earlier exposure to pill burden and potential toxicities. We investigated patients' preferences for immediate HAART initiation relative to delaying HAART for 1 year. METHODS: Consecutive patients were asked for their preference during an interview. A hypothetical difference in 3-year mortality risk between both options was systematically varied between 0% and 10% to determine the threshold at which preference would switch to HAART initiation. RESULTS: About 30% of patients preferred HAART initiation even if the mortality risk would be equal for both options. Almost 25% always preferred delaying HAART even if this would result in a 10% greater mortality risk. Most treatment guidelines recommend delaying HAART >350 CD4+ T-cells/microl. However, at a risk difference between starting and delaying HAART that corresponds with this CD4+ T-cell count, about 50% would prefer to start HAART immediately. Most guidelines recommend starting HAART below 200 CD4+ T-cells/microl. However, at a risk difference between both options corresponding with this CD4+ T-cell count, about 40% preferred delaying HAART. CONCLUSIONS: We found large variation in patients' preferences. Some patients were more inclined to initiate HAART earlier than the recommended guidelines, whereas others were more inclined to delay HAART. These findings emphasize the need for shared decision-making when deciding on the most optimal timing of HAART initiation in chronic asymptomatic HIV-1 infection.

Antiretroviral Therapy, Highly Active↗
PubMed2005

Diagnostic and clinical implications of anorectal lymphogranuloma venereum in men who have sex with men: a retrospective case-control study.

BACKGROUND: Recently, outbreaks of anorectal lymphogranuloma venereum (LGV) have occurred among men who have sex with men (MSM). This study identifies risk factors and clinical predictors of LGV to determine the implications for clinical practice. METHODS: The Chlamydia trachomatis serovars for all MSM who had anorectal chlamydia diagnosed at a sexually transmitted infection clinic in Amsterdam, The Netherlands, in 2002 and 2003 were retrospectively typed; 87 persons were infected with C. trachomatis serovar L2b and received a diagnosis of LGV. MSM infected with C. trachomatis serovars A-K and who thus had non-LGV anorectal chlamydia (n = 377) and MSM who reported having receptive anorectal intercourse but who did not have anorectal chlamydia (n = 2677) served as 2 separate control groups. Risk factors and clinical predictors were analyzed by multivariate logistic regression. Receiver operating characteristic curves were used to determine clinical relevance. RESULTS: HIV seropositivity was the strongest risk factor for LGV (odds ratio for patients with LGV vs. those with non-LGV chlamydia, 5.7 [95% confidence interval, 2.6-12.8]; odds ratio for patients with LGV vs. control subjects without chlamydia, 9.3 [95% confidence interval, 4.4-20.0]). Proctoscopic findings and elevated white blood cell counts in anorectal smear specimens were the only clinically relevant predictors for LGV infection (area under the curve of the receiver operating characteristic curve, > 0.71). Use of these 2 parameters and HIV infection status provided the highest diagnostic accuracy (for MSM with anorectal chlamydia, the area under the curve was > 0.82; sensitivity and specificity were 89% and 50%, respectively). CONCLUSIONS: LGV testing is recommended for MSM with anorectal chlamydia. If routine LGV serovar typing is unavailable, we propose administration of syndromic LGV treatment for MSM with anorectal chlamydia and either proctitis detected by proctoscopic examination, > 10 white blood cells/high-power field detected on an anorectal smear specimen, or HIV seropositivity.

Adult↗
PubMed2005

Quantitative nucleic acid sequence-based assay as a new molecular tool for detection and quantification of Leishmania parasites in skin biopsy samples.

Currently available methods for the diagnosis of cutaneous leishmaniasis (CL) have low sensitivities or are unable to quantify the number of viable parasites. This constitutes a major obstacle for the diagnosis of the disease and for the study of the effectiveness of treatment schedules and urges the development of improved detection methods. In this study, quantitative nucleic acid sequence-based amplification (QT-NASBA) technology was used to detect and quantify Leishmania parasites in skin biopsy samples from CL patients. The assay is based on the detection of a small subunit rRNA (18S rRNA), which may allow for the detection of viable parasites. The QT-NASBA assay was evaluated using in vitro-cultured promastigotes and amastigotes and 2-mm skin biopsy samples from Old and New World CL patients. The study demonstrated that the lower detection limit of the QT-NASBA was two parasites per biopsy sample. Parasites could be quantified in a range of 2 to 11,300,000 parasites per biopsy sample. The QT-NASBA could detect levels of parasites 100-fold lower than those detected by conventional PCR. Test evaluation revealed that the QT-NASBA had a sensitivity of 97.5% and a specificity of 100% in the present study. The QT-NASBA is a highly sensitive and specific method that allows quantification of both Old and New World Leishmania parasites in skin biopsy samples and may provide an important tool for diagnosis as well as for monitoring the therapy of CL patients.

Adolescent↗
PubMed2005

New lymphogranuloma venereum Chlamydia trachomatis variant, Amsterdam.

We retrospectively conducted a study of men who have sex with men who visited the Amsterdam, the Netherlands, sexually transmitted diseases clinic from January 2002 to December 2003 and had rectal Chlamydia trachomatis infections. We found that symptomatic (73%) as well as asymptomatic (43%) patients were infected with a new C. trachomatis LGV variant.

Adult↗
PubMed2005

Slow epidemic of lymphogranuloma venereum L2b strain.

We traced the Chlamydia trachomatis L2b variant in Amsterdam and San Francisco. All recent lymphogranuloma venereum cases in Amsterdam were caused by the L2b variant. This variant was also present in the 1980s in San Francisco. Thus, the current "outbreak" is most likely a slowly evolving epidemic.

Chlamydia trachomatis↗
PubMed2002

Morphometry of dermal collagen orientation by Fourier analysis is superior to multi-observer assessment.

In human dermis, collagen bundle architecture appears randomly organized, whereas in pathological conditions, such as scar tissue and connective tissue disorders, collagen bundle architecture is arranged in a more parallel fashion. Histological examination by one or two observers using polarized light is the most common method to determine collagen orientation. The hypothesis on which this study is based is that an objective image analysis technique, Fourier analysis, would improve the reliability (are the measurements reproducible?) and the accuracy (does the method measure what it is supposed to measure?) of collagen orientation assessment, compared with observer ratings. Fourier analysis was applied to 271 images of scar tissue and normal skin that were acquired by confocal laser-scanning microscopy. Observers rated the same areas using polarized light as well as the confocal microscopy images. Computer images consisting of different types of ellipses were generated with a fixed orientation. Observers and Fourier analysis evaluated the images to evaluate accuracy. The inter-observer reliability was acceptable when at least three observers rated polarized light images (r > 0.69), whereas two observers were sufficient for rating confocal microscopy images (r > 0.71). Fourier analysis correlated better with observer ratings of confocal microscopy images (r = 0.69) than with polarized light microscopy images (r = 0.42). Fourier analysis was more accurate than four observers for the evaluation of the 'true' orientation for almost all types of computer-generated images. For the first time it is shown that Fourier image analysis is suitable for the morphometry of dermal collagen orientation and leads to a superior measurement of collagen orientation compared with subjective histological evaluation by several experts. If an evaluation is performed by conventional light microscopy, at least three observers are required to attain an acceptable inter-observer reliability.

Adult↗
PubMed2002

Microcirculatory changes in travelers to a tropical country.

BACKGROUND: Travelers to tropical areas seem to be affected by nonhealing leg ulcers more frequently. One of the factors that can affect wound healing in a negative manner is leg edema. This study was performed to determine whether there is increased leg edema in travelers to tropical areas. METHOD: In this study, we measured the capillary filtration rate (CFR) of the lower leg by strain gauge plethysmography, as a measure of leg edema, on location in Surinam. Three groups were included: A, travelers in the first few weeks after arrival; B, travelers who had stayed in the tropics for a minimum of 2 months; C, native inhabitants. RESULTS: The mean CFR (mL/100 mL tissue/min) was significantly higher in group A than in groups B and C; the difference between groups B and C was not significant (group A 0.05 mL/100 mL tissue/min (standard deviation (SD), 0.03) vs. group B 0.02 mL/100 mL tissue/min (SD, 0.02), P = 0.01, and vs. group C 0.02 mL/100 mL tissue/min (SD, 0.02), P = 0.01). CONCLUSIONS: Travelers to tropical areas are affected by increased CFR in the first few weeks after arrival. A prolonged stay leads to the normalization of the CFR. Compression therapy is recommended for travelers to the tropics.

Adult↗