A causal loop diagram of older persons' emergency department visits and interactions of its contributing factors: a group model building approach

PURPOSE

Understanding the etiology of older persons' emergency department (ED) visits is highly needed. Many contributing factors have been identified, however, the role their interactions play remains unclear. Causal loop diagrams (CLDs), as conceptual models, can visualize these interactions and therefore may elucidate their role. This study aimed to better understand why people older than 65 years of age visit the ED in Amsterdam by capturing the interactions of contributing factors as perceived by an expert group in a CLD through group model building (GMB).

METHODS

Six qualitative online focus group like sessions, known as GMB, were conducted with a purposefully recruited interdisciplinary expert group of nine that resulted in a CLD that depicted their shared view.

RESULTS

The CLD included four direct contributing factors, 29 underlying factors, 66 relations between factors and 18 feedback loops. The direct factors included, 'acute event', 'frailty', 'functioning of the healthcare professional' and 'availability of alternatives for the ED'. All direct factors showed direct as well as indirect contribution to older persons' ED visits in the CLD through interaction.

CONCLUSION

Functioning of the healthcare professional and availability of alternatives for the ED were considered pivotal factors, together with frailty and acute event. These factors, as well as many underlying factors, showed extensive interaction in the CLD, thereby contributing directly and indirectly to older persons' ED visits. This study helps to better understand the etiology of older persons' ED visits and in specific the way contributing factors interact. Furthermore, its CLD can help to find solutions for the increasing numbers of older adults in the ED.

Implementing online group model building to unravel complex geriatric problems, a methodological description

BACKGROUND

Group model building (GMB), is a qualitative focus group like study design from the field of system dynamics, that leads a group of topic experts (often key stakeholders of a problem), through a set of scripted activities to create a conceptual model of their shared view on this problems' key contributing factors and their interactions. By offering a specific step wise approach to the complexity of a problem, GMB has provided better understanding and overview of complex problems across different scientific domains, in addition to traditional research methods. As the development of geriatric syndromes and organization of geriatric care are often complex issues that are difficult to research, understand and resolve, GMB might be a useful methodology to better address these issues. This study aimed to describe the methodology of online GMB using a geriatric case study.

METHODS

Four online GMB sessions were designed by two clinician researchers. A GMB methodology expert was consulted for optimal design. Scriptapedia scripts formed the core of the sessions. These scripts were adapted to the online format. Experts were recruited purposefully and included seven local health care professionals, one patient representative and one healthcare insurance data analyst. The outcome was a conceptual model of older adults' emergency department visits, which was discussed in a separate article.

RESULTS

During implementation of these four sessions, the sessions were adjusted and two extra (non-scripted) sessions were added because defining unambiguous contributing factors to the geriatric case was challenging for the experts. Paraphrasing, categorizing, iterative plenary reflection, and reserving extra time were used to help experts overcome this challenge. All sessions were held in April and May 2021.

CONCLUSION

This study shows that GMB can help unravel complex problems in geriatrics, both pathophysiological as organizational, by creating step wise overview of their key contributing factors and interactions. Furthermore, it shows that GMB can be used by clinicians, researchers and health policy makers to better understand complex geriatric problems. Moreover, this paper can help to overcome specific implementational challenges in the geriatric field.

The recurring features of molecular subtypes in distinct gastrointestinal malignancies-A systematic review

In colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC) and gastric cancer (GC) multiple studies of inter-tumor heterogeneity have identified molecular subtypes, which correlate with clinical features. Our aim was to investigate the attributes of molecular subtypes across three different gastrointestinal cancer types. We performed a systematic search for publications on molecular subtypes or classifications in PDAC and GC and compared the described subtypes with the established consensus molecular subtypes of CRC. Examining the characteristics of subtypes across CRC, PDAC and GC resulted in four categories of subtypes. We describe uniting and distinguishing features within a mesenchymal, an epithelial, an immunogenic and a metabolic and digestive subtype category. We conclude that molecular subtypes of CRC, PDAC and GC display relevant overlap in molecular features and clinical outcomes. This finding encourages quantitative studies on subtypes across different cancer types and could lead to a paradigm shift in future treatment strategies.

Phosphorylation of FADD/ MORT1 at serine 194 and association with a 70-kDa cell cycle-regulated protein kinase

The adapter molecule Fas-associated death domain protein (FADD)/mediator of receptor-induced toxicity-1 (MORT1) is essential for signal transduction of the apoptosis-inducing receptor CD95 (APO-1/Fas) as it connects the activated receptor with the effector caspase-8. FADD also plays a role in embryonic development and the cell cycle reentry of T cells. FADD is phosphorylated at serine residues. We now show that phosphorylation exclusively occurs at serine 194. The phosphorylation of FADD was found to correlate with the cell cycle. In cells arrested at the G2/M boundary with nocodazole, FADD was quantitatively phosphorylated, whereas only nonphosphorylated FADD was found in cells arrested in G1/S with hydroxyurea. In this context, we have identified a 70-kDa cell cycle-regulated kinase that specifically binds to the C-terminal half of FADD. Because CD95-mediated apoptosis is independent of the cell cycle, phosphorylation of FADD may regulate its apoptosis-independent functions.

Ectopic expression of Cdc25A accelerates the G(1)/S transition and leads to premature activation of cyclin E- and cyclin A-dependent kinases

Human Cdc25 phosphatases play important roles in cell cycle regulation by removing inhibitory phosphates from tyrosine and threonine residues of cyclin-dependent kinases. Three human Cdc25 isoforms, A, B, and C, have been discovered. Cdc25B and Cdc25C play crucial roles at the G(2)/M transition. In the present study, we have investigated the function of human Cdc25A phosphatase. Cell lines that express human Cdc25A in an inducible manner have been generated. Ectopic expression of Cdc25A accelerates the G(1)/S-phase transition, indicating that Cdc25A controls an event(s) that is rate limiting for entry into S phase. Furthermore, we carried out a detailed analysis of the expression and activation of human Cdc25A. Activation of endogenous Cdc25A occurs during late G(1) phase and increases in S and G(2) phases. We further demonstrate that Cdc25A is activated at the same time as cyclin E- and cyclin A-dependent kinases. In vitro, Cdc25A dephosphorylates and activates the cyclin-Cdk complexes that are active during G(1). Overexpression of Cdc25A in the inducible system, however, leads to a premature activation of both cyclin E-Cdk2 and cyclin A-Cdk2 complexes, while no effect of cyclin D-dependent kinases is observed. Furthermore, Cdc25A overexpression induces a tyrosine dephosphorylation of Cdk2. These results suggest that Cdc25A is an important regulator of the G(1)/S-phase transition and that cyclin E- and cyclin A-dependent kinases act as direct targets.

Lyme borreliosis in rheumatological practice: identification of Lyme arthritis and diagnostic aspects in a Swedish county with high endemicity

To prospectively study the prevalence of Lyme arthritis, 100 consecutive patients referred to a rheumatology out-patient clinic and 115 patients with a classified rheumatological disease were included. Individuals seropositive for antibody against the Borrelia burgdorferi sensu lato complex were examined for clinical signs or a history of Lyme borreliosis. Positive titres against B. burgdorferi s.l. were found in 7/100 and 15/115, respectively. Among the 100 referred patients. Lyme arthritis was diagnosed in five cases. Carpal tunnel syndrome was the presenting clinical feature in two of them. One of the 115 individuals with a previously classified rheumatological disease was re-classified as Lyme arthritis. All cases of Lyme arthritis improved after oral antibiotic treatment. This study revealed Lyme arthritis to be a common disorder in this part of Sweden and the diagnosis should be considered in patients with acute or recurrent episodes of mono- or oligoarthritis.

Long-term changes of body weight and cardiovascular risk factors after weight reduction with group therapy and dexfenfluramine

The aim of this work was to investigate the long-term changes of body weight and cardiovascular risk factors after weight reduction with dexfenfluramine (dF) compared to placebo (pI) and additional group therapy. There was a 3 year follow-up of obese patients after 1 year double-blind, randomized treatment with 30mg dF or pI and group therapy. The work was carried out at the outpatient clinic of University Hospital, Tübingen. Forty-eight (24 dF, 24 pI) patients were investigated with more than 120% of ideal body weight. Body weight, blood pressure, blood glucose, serum cholesterol and triglycerides were measured. During 1 year of treatment body weight fell by 11.2% (dF) and 9.1% (pI) (P < 0.001 for time, n.s. for dF/pI), systolic blood pressure by 7.3 and 9.9 mm Hg (P = 0.044/n.s.). There were no significant changes of serum cholesterol, triglycerides, and blood glucose. At the follow-up of 22 (11/11) patients 3 years later, the dF group had regained more than the lost weight; the placebo group had lost 2.4% of the initial body weight. Serum cholesterol (dF + 0.64/pI + 0.65 mmol/l, P = 0.010/n.s.), triglycerides (+0.74/+0.59 mmol/l, P = 0.002/n.s.), and blood glucose (+0.56/+0.81mmol/l, P < 0.001/n.s.) increased significantly. Systolic blood pressure increased slightly, diastolic blood pressure did not change significantly. Without appropriate prevention of weight regain even combined weight reduction therapy over a period of one year results in weight regain and deterioration of cardiovascular risk factors.

Restriction enzyme analysis of human cytomegalovirus using DNA extracted from infected cells

Cytomegalovirus (CMV) isolates were investigated by restriction enzyme analysis. A method for extraction of cellular CMV DNA is described which uses CMV DNA released into the Hirt supernatant after precipitation of cellular DNA. CMV DNA is further purified by ultracentrifugation in neutral sucrose gradient. Fifteen strains from unrelated patients all had unique cleavage patterns with three restriction enzymes, although many of the fragments comigrated. Strains from related patients mostly showed identical patterns. The CMV genome seems to be stable since the pattern did not change in five isolates obtained from the same patient during a 5-year period.

The role of immunoglobulins in amniotic fluid growth inhibition of Bacteroides fragilis, herpes simplex, coxsackie B 5 and cytomegalovirus

In serum and amniotic fluid (AF) from 30 pregnant women, antibodies against the anaerobe Bacteroides fragilis were determined by enzyme-linked immunosorbent assay (ELISA) and the results were compared with those of previously performed tests of B. fragilis growth inhibition by AF. The neutralizing effects of serum and AF against herpes simplex virus (HSV), cytomegalovirus (CMV) and coxsackie B 5 virus were also investigated, and antibody titres were determined by ELISA. No correlation could be demonstrated between the growth-inhibitory capacity of AF and the presence of antibodies against B. fragilis in serum or AF. Neutralizing antibodies against HSV and coxsackie B 5 virus were found in 73% and 51%, respectively, of the sera and in 36% and 13%, respectively, of both serum and corresponding AF. In no case could an AF neutralizing effect upon HSV, coxsackie B5 or CMV be demonstrated without a corresponding positive serum neutralization. It is concluded that the growth-inhibitory effect of AF on viruses in antibody-mediated, while AF inhibition of B. fragilis, and possibly other bacteria as well, seems to depend upon other antimicrobial mechanisms.