Saxon Epidemiological Study in General Practice-6 (SESAM-6): protocol of a cross-sectional study.

INTRODUCTION: General practitioners (GPs) are mostly the first point of contact for patients with health problems in Germany. There is only a limited epidemiological overview data that describe the GP consultation hours based on other than billing data. Therefore, the aim of Saxon Epidemiological Study in General Practice-6 (SESAM-6) is to examine the frequency of reasons for encounter, prevalence of long-term diagnosed diseases and diagnostic and therapeutic decisions in general practice. This knowledge is fundamental to identify the healthcare needs and to develop strategies to improve the GP care. The results of the study will be incorporated into the undergraduate, postgraduate and continuing medical education for GP. METHODS AND ANALYSIS: This cross-sectional study SESAM-6 is conducted in general practices in the state of Saxony, Germany. The study design is based on previous SESAM studies. Participating physicians are assigned to 1 week per quarter (over a survey period of 12 months) in which every fifth doctor-patient contact is recorded for one-half of the day (morning or afternoon). To facilitate valid statements, a minimum of 50 GP is required to document a total of at least 2500 doctor-patient contacts. Univariable, multivariable and subgroup analyses as well as comparisons to the previous SESAM data sets will be conducted. ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee of the Technical University of Dresden in March 2023 (SR-EK-7502023). Participation in the study is voluntary and will not be remunerated. The study results will be published in peer-reviewed scientific journals, preferably with open access. They will also be disseminated at scientific and public symposia, congresses and conferences. A final report will be published to summarise the central results and provided to all study participants and the public.

Factors promoting willingness to practice medicine in rural regions and awareness of rural regions in the university's catchment area - cross-sectional survey among medical students in central Germany.

Aim: Many universities offer rural medical internships for medical students. The present survey was designed to show how rural medical work is perceived by students, whether these perceptions are associated with origin and previous experience, and how well medical students know rural regions in the vicinity of their university. In addition, students were asked how to support and inspire medical students to later work in a rural region. Methods: This cross-sectional study was based on an anonymous online survey of medical students at the Universities of Halle-Wittenberg and Leipzig. The evaluations included descriptive statistics, statistical group comparisons, and qualitative content analysis of free text answers. Results: A total of 882 students took part in the survey. Students who had grown up in a rural region or had lived there for a longer time (71.7% of the respondents) rated the work-life balance better (p<0.01) and the patient variety in the countryside slightly higher (p<0.05) than their fellow students from the big city. Students who had worked in a rural practice or hospital before (62.2%) rated patient diversity (p<0.001) and work variety (p<0.001), as well as workload (p<0.01), slightly higher in rural areas than students with no prior experience. On average, the specified rural model regions were still unknown to more than 60% of the students. The suggestions for attracting medical students to later work as rural physicians included financial incentives and, above all, better information about life as a rural physician and the rural regions. Conclusion: Thus, the medical faculties of the universities as well as the counties threatened by medical undersupply should further expand the transfer of knowledge and experience regarding rural physician life for the students.

Ability of dietary factors to affect homocysteine levels in mice: a review.

Homocysteine is associated with several diseases, and a series of dietary factors are known to modulate homocysteine levels. As mice are often used as model organisms to study the effects of dietary hyperhomocysteinemia, we collected data about concentrations of vitamin B12, vitamin B6, folate, methionine, cystine, and choline in mouse diets and the associated plasma/serum homocysteine levels. In addition, we more closely examined the composition of the control diet, the impact of the mouse strain, sex and age, and the duration of the dietary intervention on homocysteine levels. In total, 113 out of 1103 reviewed articles met the inclusion criteria. In the experimental and control diets, homocysteine levels varied from 0.1 to 280 µmol/l. We found negative correlations between dietary vitamin B12 (rho = - 0.125; p < 0.05), vitamin B6 (rho = - 0.191; p < 0.01) and folate (rho = - 0.395; p < 0.001) and circulating levels of homocysteine. In contrast, a positive correlation was observed between dietary methionine and homocysteine (methionine: rho = 0.146; p < 0.05). No significant correlations were found for cystine or choline and homocysteine levels. In addition, there was no correlation between the duration of the experimental diets and homocysteine levels. More importantly, the data showed that homocysteine levels varied widely in mice fed control diets as well. When comparing control diets with similar nutrient concentrations (AIN-based), there were significant differences in homocysteine levels caused by the strain (ANOVA, p < 0.05) and age of the mice at baseline (r = 0.47; p < 0.05). When comparing homocysteine levels and sex, female mice tended to have higher homocysteine levels than male mice (9.3 ± 5.9 µmol/l vs. 5.8 ± 4.5 µmol/l; p = 0.069). To conclude, diets low in vitamin B12, vitamin B6, or folate and rich in methionine are similarly effective in increasing homocysteine levels. AIN recommendations for control diets are adequate with respect to the amounts of homocysteine-modulating dietary parameters. In addition, the mouse strain and the age of mice can affect the homocysteine level.

Vitamin D, Epstein-Barr virus, and endogenous retroviruses in multiple sclerosis - facts and hypotheses.

The pathogenesis of multiple sclerosis (MS) remains poorly understood. Presumably, MS is caused by multiple environmental, epigenetic, and genetic factors. Among them, human endogenous retroviruses (HERVs), Epstein-Barr virus (EBV) and vitamin D have been suggested to play a role in the pathogenesis and course of MS. Because vitamin D can affect the immune system and infections, it can be hypothesized that there is a close interplay between vitamins, EBV and ERV in the pathogenesis of MS. Here, we summarize the important data on vitamin D, including polymorphisms in genes related to vitamin D metabolism, EBV and ERV, in the pathogenesis of MS and create hypotheses regarding their interactions. Data indicate that vitamin D has a strong impact on viral infections and interferes with EBV infection, while EBV is capable of activating silent ERVs. We believe that EBV could be the missing link between vitamin D and ERV in MS pathogenesis.

Impact of dietary propionate on fructose-induced changes in lipid metabolism, gut microbiota and short-chain fatty acids in mice.

Propionate has antimicrobial activity and is suggested to influence lipid metabolism. Here, we investigated the effect of propionate on lipid metabolism and the gut microbiome in fructose-fed mice as a model of diet-induced steatosis and gut dysbiosis. Therefore, 48 male wild-type mice were fed isoenergetic diets with either 0% fructose (F-) or 40% fructose (F+) that contained 0% propionate (P-) or 1% propionate (P+) for 7 weeks. Mice that received the F+ diets developed fatty livers, had fewer small intestinal proteobacteria and colonic actinobacteria and were characterised by changes in bacterial genera (e.g., Allobaculum, Lachnospiraceae, and Escherichia). Interestingly, mice fed the F+ diets had higher levels of propionate and butyrate in the circulation than mice fed the F- diets (p < 0.05). Treatment with propionate influenced neither hepatic or plasma lipids nor levels of circulating SCFAs. With the exception of Verrucomicrobia, other bacterial phyla were not affected by propionate.

Agrimonia procera exerts antimicrobial effects, modulates the expression of defensins and cytokines in colonocytes and increases the immune response in lipopolysaccharide-challenged piglets.

BACKGROUND: Because antibiotic use in livestock is assumed to contribute to the emerging public health crisis of antibiotic resistance, alternatives are required. Phytogenic additives are extensively studied due to their antibiotic properties. Components of Agrimonia species have been reported as candidate antimicrobials that possess antioxidative and anti-inflammatory properties. We studied the impact of Agrimonia procera (AP) on the growth of selected strains of gut bacteria, the effect of AP on the mRNA abundance of genes involved in inflammation and bacterial defense in a colon carcinoma cell line, the effect of AP in piglets challenged with lipopolysaccharides, and the effect of AP on the growth performance of healthy piglets. RESULTS: The in vitro growth rate of different bacteria strains was negatively affected by AP, especially in Pediococcus pentosaceus and all tested E. coli strains. Stimulation of Caco-2 cells with TNFα resulted in elevated mRNA expression of CXCL1, IL-8 and GPX2. After pretreatment of cells with AP, stimulation of Caco-2 cells with TNFα still resulted in elevated mRNA expression of CXCL1 and IL-8 at all measured points in time. However, mRNA expression in AP-pretreated cells was lower after 6 h and 24 h. In addition, expression of DEFB1 and GPX2 was significantly elevated after TNFα stimulation. In vivo, application of lipopolysaccharides induced significantly increased animal body temperatures. Piglets pretreated with AP prior to lipopolysaccharide application showed a faster and larger increase in body temperature than controls. In addition, piglets pretreated with AP appeared to release more TNFα than controls. In healthy piglets, AP treatment had no impact on growth performance parameters. Fecal dry matter and total plasma antioxidant capacity tended to be higher in piglets treated with AP than in control piglets (P = 0.055 and P = 0.087, respectively). CONCLUSIONS: AP has antimicrobial effects in vitro and stimulated the expression of proinflammatory cytokines in Caco-2 cells. The additive had no effect on growth in healthy piglets but increased the immune response in LPS-treated animals. In addition, AP appeared to have antioxidative effects in vivo. Therefore, AP merits testing as a future alternative to antibiotics in animal husbandry.

Investigation of Endogenous Retrovirus Sequences in the Neighborhood of Genes Up-regulated in a Neuroblastoma Model after Treatment with Hypoxia-Mimetic Cobalt Chloride.

Human endogenous retroviruses (ERVs) have been found to be associated with different diseases, e.g., multiple sclerosis (MS). Most human ERVs integrated in our genome are not competent to replicate and these sequences are presumably silent. However, transcription of human ERVs can be reactivated, e.g., by hypoxia. Interestingly, MS has been linked to hypoxia since decades. As some patterns of demyelination are similar to white matter ischemia, hypoxic damage is discussed. Therefore, we are interested in the association between hypoxia and ERVs. As a model, we used human SH-SY5Y neuroblastoma cells after treatment with the hypoxia-mimetic cobalt chloride and analyzed differences in the gene expression profiles in comparison to untreated cells. The vicinity of up-regulated genes was scanned for endogenous retrovirus-derived sequences. Five genes were found to be strongly up-regulated in SH-SY5Y cells after treatment with cobalt chloride: clusterin, glutathione peroxidase 3, insulin-like growth factor 2, solute carrier family 7 member 11, and neural precursor cell expressed developmentally down-regulated protein 9. In the vicinity of these genes we identified large (>1,000 bp) open reading frames (ORFs). Most of these ORFs showed only low similarities to proteins from retro-transcribing viruses. However, we found very high similarity between retrovirus envelope sequences and a sequence in the vicinity of neural precursor cell expressed developmentally down-regulated protein 9. This sequence encodes the human endogenous retrovirus group FRD member 1, the encoded protein product is called syncytin 2. Transfection of syncytin 2 into the well-characterized Ewing sarcoma cell line A673 was not able to modulate the low immunostimulatory activity of this cell line. Future research is needed to determine whether the identified genes and the human endogenous retrovirus group FRD member 1 might play a role in the etiology of MS.

Genetic Determinants of Antibody Levels in Cerebrospinal Fluid in Multiple Sclerosis: Possible Links to Endogenous Retroviruses.

The pathogenesis of multiple sclerosis (MS) has not been clarified. In addition to environmental factors; genetic determinants have been implicated in the pathogenesis of MS. Furthermore, endogenous retroviruses (ERV) might play a role in MS. The presence of oligoclonal immunoglobulin in cerebrospinal fluid (CSF) is a typical feature of MS. Recently, genetic polymorphisms in loci on human chromosomes 6, 14 and 18 have been identified as major determinants of CSF antibody levels in MS. The functional relevance of these single nucleotide polymorphisms (SNPs) remains unclear and none of them is located in an open reading frame. In previous studies, we identified ERV sequences in the vicinity of MS associated SNPs. Here, we describe the identification of ERV sequences in the neighborhood of SNPs associated with CSF antibody levels. All of the identified SNPs are located in the vicinity of ERV sequences. One of these sequences has very high homology to a sequence derived from the so-called MS-associated retrovirus (MSRV). Another cluster of three ERV sequences from the immunoglobulin heavy chain locus has retained the typical organization of retroviral genomes. These observations might shed new light on a possible association between ERVs and MS pathogenesis.

Cooccurrences of Putative Endogenous Retrovirus-Associated Diseases.

At least 8% of the human genome is composed of endogenous retrovirus (ERV) sequences. ERVs play a role in placental morphogenesis and can sometimes protect the host against exogenous viruses. On the other hand, ERV reactivation has been found to be associated with different diseases, for example, multiple sclerosis (MS), schizophrenia, type 1 diabetes mellitus (T1D), or amyotrophic lateral sclerosis (ALS). Little is known about the cooccurrence of these diseases. If all these diseases are caused by ERV, antiretroviral therapy should perhaps also show some effects in the other diseases. Here, we summarize literature demonstrating that some ERV-associated diseases seem to appear together more often than expected, for example, MS and ALS, MS and T1D, MS and schizophrenia, or ALS and T1D. In contrast, some ERV-associated diseases seem to appear together less frequently than expected, for example, schizophrenia and T1D. Besides, some reports demonstrate amelioration of MS, ALS, or schizophrenia under antiretroviral therapy in human immunodeficiency virus-infected patients. If such results could be confirmed in larger studies, alternative therapy strategies for ERV-associated diseases like MS and schizophrenia might be possible.

Endogenous Retrovirus 3 - History, Physiology, and Pathology.

Endogenous viral elements (EVE) seem to be present in all eukaryotic genomes. The composition of EVE varies between different species. The endogenous retrovirus 3 (ERV3) is one of these elements that is present only in humans and other Catarrhini. Conservation of ERV3 in most of the investigated Catarrhini and the expression pattern in normal tissues suggest a putative physiological role of ERV3. On the other hand, ERV3 has been implicated in the pathogenesis of auto-immunity and cancer. In the present review we summarize knowledge about this interesting EVE. We propose the model that expression of ERV3 (and probably other EVE loci) under pathological conditions might be part of a metazoan SOS response.

A survey of endogenous retrovirus (ERV) sequences in the vicinity of multiple sclerosis (MS)-associated single nucleotide polymorphisms (SNPs).

Although multiple sclerosis (MS) is one of the most common central nervous system diseases in young adults, little is known about its etiology. Several human endogenous retroviruses (ERVs) are considered to play a role in MS. We are interested in which ERVs can be identified in the vicinity of MS associated genetic marker to find potential initiators of MS. We analysed the chromosomal regions surrounding 58 single nucleotide polymorphisms (SNPs) that are associated with MS identified in one of the last major genome wide association studies. We scanned these regions for putative endogenous retrovirus sequences with large open reading frames (ORFs). We observed that more retrovirus-related putative ORFs exist in the relatively close vicinity of SNP marker indices in multiple sclerosis compared to control SNPs. We found very high homologies to HERV-K, HCML-ARV, XMRV, Galidia ERV, HERV-H/env62 and XMRV-like mouse endogenous retrovirus mERV-XL. The associated genes (CYP27B1, CD6, CD58, MPV17L2, IL12RB1, CXCR5, PTGER4, TAGAP, TYK2, ICAM3, CD86, GALC, GPR65 as well as the HLA DRB1*1501) are mainly involved in the immune system, but also in vitamin D regulation. The most frequently detected ERV sequences are related to the multiple sclerosis-associated retrovirus, the human immunodeficiency virus 1, HERV-K, and the Simian foamy virus. Our data shows that there is a relation between MS associated SNPs and the number of retroviral elements compared to control. Our data identifies new ERV sequences that have not been associated with MS, so far.