Aspects of human chlamydial infections

This thesis takes a closer look at three aspects of human chlamydial infections. With regard to diagnosis the influence of logistics on the sensitivity of the culture method is discussed, along with optimalization of the culture itself and an evaluation of new diagnostic methods. Next, epidemiological data are discussed with regard to the prevalence and role of Chlamydia, on the one hand in asymptomatic persons from low-risk groups and on the other hand in women with postinflammatory tubal infertility. Finally the therapeutic problems are considered with reference to measurements of the in-vitro sensitivity of various chlamydial strains to tetracycline and some recently developed chemotherapeutic agents. The significance of Chlamydia for some of the sexually transmitted nongonococcal oculogeni tal infections was not generally recognised until relatively recently. One of the reasons for this was undou~tedly the lack of a culture method to isolate the organism for study of its biological characteristics. Even after the introduction of a technique to culture Chlamydia on cell lines, large scale epidemiological research was impeded by lack of adequately equipped laboratories where the complicated method might be employed. The manner of collecting patient material for culture, transport from outpatient clinic to laboratory, and the culture method employed are critical parameters which determine the ultimate result. A disadvantage of the culture method is the relatively long time required (6 days). Rapid diagnosis and if necessary treatment, especially of asymptomatic persons, is of great epidemiological importance. Chlamydial antigen-detecting methods have recently been developed which can present results within a few hours. They are based on the immunofluorescence (IF) technique and on the enzyme immunoassay (EIA). Both techniques employ monoclonal antibodies against genus-specific epitopes of the Major Outer Membrane Protein (IF technique) or of the lipopolysaccharide (EIA). The chlamydiae in patient material need no longer be alive for analysis, and transport to the laboratory therefore no longer influences the sensitivity of detection

Effective Detection and Treatment of Amblyopia: Addressing Noncompliance

Amblyopia (a ‘lazy eye’) is commonly defined as a decrease in visual acuity (sight) in either or both eyes which persists after correction of the refractive error (by wearing glasses) and / or removal of any pathological obstacle to vision (Ansons et al. 2009). In the clinical setting amblyopia is generally expressed as a loss of visual acuity, and it usually presents itself during the ophthalmological examination by the ophthalmologist or the orthoptist (Levi 2006). It is usually associated with the presence of amblyogenic factors such as strabismus (ocular misalignment causing each eye to have a different image on the fovea), a refractive error (one foveal image is more blurred than the other); or, in rare cases, deprivation of a clear retinal image (physical obstruction, e.g. infantile cataract or ptosis) (Ciuffreda 1991; Von Noorden 1967, 1985; Von Noorden et al. 2002b)

Multiple usage of the CD PLUS/UNIX system: performance in practice

In August 1994, the CD PLUS/Ovid literature retrieval system based on UNIX was activated for the Faculty of Medicine and Health Sciences of Erasmus University in Rotterdam, the Netherlands. There were up to 1,200 potential users. Tests were carried out to determine the extent to which searching for literature was affected by other end users of the system. In the tests, search times and download times were measured in relation to a varying number of continuously active workstations. Results indicated a linear relationship between search times and the number of active workstations. In the "worst case" situation with sixteen active workstations, the time required for record retrieval increased by a factor of sixteen and downloading time by a factor of sixteen over the "best case" of no other active stations. However, because the worst case seldom, if ever, happens in real life, these results are considered acceptable

Klebsiella aerogenes adhesion behaviour during biofilm formation on monazite

The adsorption behaviour of micro-organisms during the initial attachment stage of biofilm formation affects subsequent stages. The available area for attachment and the chemophysical properties of a surface affect microbial attachment performance. This study focused on the initial attachment behaviour of Klebsiella aerogenes on monazite by measuring the ratio of planktonic against sessile subpopulations (P:S ratio), and the potential role of extracellular DNA (eDNA). eDNA production, effects of physicochemical properties of the surface, particle size, total available area for attachment, and the initial inoculation size on the attachment behaviour were tested. K. aerogenes attached to monazite immediately after exposure to the ore; however, the P:S ratio significantly (p = 0.05) changed in response to the particle size, available area, and inoculation size. Attachment occurred preferentially on larger-sized (~50 µm) particles, and either decreasing the inoculation size or increasing the available area further promoted attachment. Nevertheless, a portion of the inoculated cells always remained in a planktonic state. K. aerogenes produced lower eDNA in response to the changed surface chemical properties when monazite was replaced by xenotime. Using pure eDNA to cover the monazite surface significantly (p ≤ 0.05) hindered bacterial attachment due to the repulsive interaction between the eDNA layer and bacteria

The Doctor in Literature. Volume 4. Gender and Sex

This book is the fourth of four volumes in the series The Doctor in Literature. Like the first three it is intended to serve as an indexed, annotated anthology and to bring together a total of some 1500 extracts from approximately 600 works of fiction where medical doctors appear as major or minor characters. The citations in volume 4 relate to sex and gender as these issues affect physicians and medical practice, There is a lengthy chapter discussing fictional female doctors and the perceived differences between these women and their male colleagues. Nurses (generally female) and their interactions with doctors (generally male) are discussed in three chapters. Sexual encounters between patients and doctors form the subject of the last chapter

Early prediction of severe retinopathy of prematurity requiring laser treatment using physiological data

Background Early risk stratification for developing retinopathy of prematurity (ROP) is essential for tailoring screening strategies and preventing abnormal retinal development. This study aims to examine the ability of physiological data during the first postnatal month to distinguish preterm infants with and without ROP requiring laser treatment. Methods In this cohort study, preterm infants with a gestational age <32 weeks and/or birth weight <1500 g, who were screened for ROP were included. Differences in the physiological data between the laser and non-laser group were identified, and tree-based classification models were trained and independently tested to predict ROP requiring laser treatment. Results In total, 208 preterm infants were included in the analysis of whom 30 infants (14%) required laser treatment. Significant differences were identified in the level of hypoxia and hyperoxia, oxygen requirement, and skewness of heart rate. The best model had a balanced accuracy of 0.81 (0.72–0.87), a sensitivity of 0.73 (0.64–0.81), and a specificity of 0.88 (0.80–0.93) and included the SpO2/FiO2 ratio and baseline demographics (including gestational age and birth weight). Conclusions Routinely monitored physiological data from preterm infants in the first postnatal month are already predictive of later development of ROP requiring laser treatment, although validation is required in larger cohorts. Impact Routinely monitored physiological data from the first postnatal month are predictive of later development of ROP requiring laser treatment, although model performance was not significantly better than baseline characteristics (gestational age, birth weight, sex, multiple birth, prenatal glucocorticosteroids, route of delivery, and Apgar scores) alone. A balanced accuracy of 0.81 (0.72–0.87), a sensitivity of 0.73 (0.64–0.81), and a specificity of 0.88 (0.80–0.93) was achieved with a model including the SpO2/FiO2 ratio and baseline characteristics. Physiological data have potential to play a significant role for future ROP prediction and provide opportunities for early interventions to protect infants from abnormal retinal development

Sociocultural and psychological determinants in migrants for noncompliance with occlusion therapy for amblyopia

Background: Compliance with occlusion therapy for amblyopia in children is low when their parents have a low level of education, speak Dutch poorly, or originate from another country. We determined how sociocultural and psychological determinants affect compliance. Methods: Included we

Single-nucleus RNA sequencing of pre-malignant liver reveals disease-associated hepatocyte state with HCC prognostic potential

Current approaches to staging chronic liver diseases have limited utility for predicting liver cancer risk. Here, we employed single-nucleus RNA sequencing (snRNA-seq) to characterize the cellular microenvironment of healthy and pre-malignant livers using two distinct mouse models. Downstream analyses unraveled a previously uncharacterized disease-associated hepatocyte (daHep) transcriptional state. These cells were absent in healthy livers but increasingly prevalent as chronic liver disease progressed. Copy number variation (CNV) analysis of microdissected tissue demonstrated that daHep-enriched regions are riddled with structural variants, suggesting these cells represent a pre-malignant intermediary. Integrated analysis of three recent human snRNA-seq datasets confirmed the presence of a similar phenotype in human chronic liver disease and further supported its enhanced mutational burden. Importantly, we show that high daHep levels precede carcinogenesis and predict a higher risk of hepatocellular carcinoma development. These findings may change the way chronic liver disease patients are staged, surveilled, and risk stratified

Clinical course of cone dystrophy caused by mutations in the RPGR gene

Contains fulltext : 97720.pdf (publisher's version ) (Closed access)BACKGROUND: Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. METHODS: We investigated an X-linked cone dystrophy family (1) with 25 affected males, 25 female carriers, and 21 non-carriers, as well as a small family (2) with one affected and one unaffected male. The RPGR gene was analyzed by direct sequencing. All medical records were evaluated, and all available data on visual acuity, color vision testing, ophthalmoscopy, fundus photography, fundus autofluorescence, Goldmann perimetry, SD-OCT, dark adaptation, and full-field electroretinography (ERG) were registered. Cumulative risks of visual loss were studied with Kaplan-Meier product-limit survival analysis. RESULTS: Both families had a frameshift mutation in ORF15 of the RPGR gene; family 1 had p.Ser1107ValfsX4, and family 2 had p.His1100GlnfsX10. Mean follow up was 13 years (SD 10). Virtually all affected males showed reduced photopic and normal scotopic responses on ERG. Fifty percent of the patients had a visual acuity of <0.5 at age 35 years (SE 2.2), and 75% of the patients was legally blind at age 60 years (SE 2.3). Female carriers showed no signs of ocular involvement. CONCLUSIONS: This report describes the clinical course and visual prognosis in two families with cone dystrophy due to RPGR mutations in the 3' terminal region of ORF15. Remarkable features were the consistent, late-onset phenotype, the severe visual outcome, and the non-expression in female carriers. Expression of RPGR mutations in this particular region appears to be relatively homogeneous and predisposed to cones