A practical guide to mathematical methods for estimating infectious disease outbreak risks.

Mathematical models are increasingly used throughout infectious disease outbreaks to guide control measures. In this review article, we focus on the initial stages of an outbreak, when a pathogen has just been observed in a new location (e.g., a town, region or country). We provide a beginner's guide to two methods for estimating the risk that introduced cases lead to sustained local transmission (i.e., the probability of a major outbreak), as opposed to the outbreak fading out with only a small number of cases. We discuss how these simple methods can be extended for epidemiological models with any level of complexity, facilitating their wider use, and describe how estimates of the probability of a major outbreak can be used to guide pathogen surveillance and control strategies. We also give an overview of previous applications of these approaches. This guide is intended to help quantitative researchers develop their own epidemiological models and use them to estimate the risks associated with pathogens arriving in new host populations. The development of these models is crucial for future outbreak preparedness. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".

A direct comparison of methods for assessing the threat from emerging infectious diseases in seasonally varying environments.

Seasonal variations in environmental conditions lead to changing infectious disease epidemic risks at different times of year. The probability that early cases initiate a major epidemic depends on the season in which the pathogen enters the population. The instantaneous epidemic risk (IER) can be tracked. This quantity is straightforward to calculate, and corresponds to the probability of a major epidemic starting from a single case introduced at time t=t0, assuming that environmental conditions remain identical from that time onwards (i.e. for all t≥t0). However, the threat when a pathogen enters the population in fact depends on changes in environmental conditions occurring within the timescale of the initial phase of the outbreak. For that reason, we compare the IER with a different metric: the case epidemic risk (CER). The CER corresponds to the probability of a major epidemic starting from a single case entering the population at time t=t0, accounting for changes in environmental conditions after that time. We show how the IER and CER can be calculated using different epidemiological models (the stochastic Susceptible-Infectious-Removed model and a stochastic host-vector model that is parameterised using temperature data for Miami) in which transmission parameter values vary temporally. While the IER is always easy to calculate numerically, the adaptable method we provide for calculating the CER for the host-vector model can also be applied easily and solved using widely available software tools. In line with previous research, we demonstrate that, if a pathogen is likely to either invade the population or fade out on a fast timescale compared to changes in environmental conditions, the IER closely matches the CER. However, if this is not the case, the IER and the CER can be significantly different, and so the CER should be used. This demonstrates the need to consider future changes in environmental conditions carefully when assessing the risk posed by emerging pathogens.

Pediatric epilepsy and psychoeducational interventions: A review of the literature.

For many individuals, living with epilepsy is truly a family affair throughout the life span. When it comes to childhood epilepsy, the unpredictability of seizure patterns, comorbid conditions, the risk of sudden unexpected death in epilepsy (SUDEP), and societal stigma can be emotionally taxing on children and their primary caregivers. To this end, this article proposes to review psychoeducational interventions provided to primary caregivers of children with an epilepsy diagnosis and the impact of such interventions on general parental coping skills. There were three main themes identified (1) caregivers' knowledge and self-efficacy about seizure management; (2) parental epilepsy-related fears, anxiety, and stress; (3) parental sleep quality and SUDEP psychoeducation. Overall, considering research limitations, providing epilepsy-related psychoeducational interventions to primary caregivers of children with epilepsy seems to have promising evidence in the literature. After receiving such interventions, the studies show that caregivers' psychosocial outcomes improved; they become more empowered to manage their children's seizures and advocate for their children's psychosocial needs.

Relationship Between Spiritual Well-Being and Hope in Patients with Cardiovascular Disease.

Spirituality and hope have been identified as important constructs in health research, since both are thought to enhance a person's ability to cope with the consequences of serious illness. The aim of this study was to examine the relationship between spiritual well-being and hope in patients with cardiovascular disease. Using descriptive, correlational methodology, the investigator gathered data on a convenience sample of 500 patients with cardiovascular disease who were hospitalized in a medical institution in Iran. The study was conducted over a four-month period. Participants completed a demographic questionnaire, the Spiritual Well-Being Scale (SWBS) and the Herth Hope Index (HHI). The mean score on the SWBS and HHI was 86.21 (SD 12.46) and 34.80 (SD 5.05), respectively. Multivariate predictors for spiritual well-being were female gender (p = 0.047), religiosity (p = 0.018), and hope (p < 0.001). Significant predictors of hope were marital status (p < 0.001), educational status (p < 0.001), economic status (p < 0.001), and spiritual well-being (p < 0.001). Findings suggest that multiple factors may impact spiritual well-being and hope. Therefore, this study has implications for those providing care to patients with cardiovascular disease.

Inadvertent intrathecal injections and best practice management.

The intrathecal space has become an important anatomic site for medical intervention not only in anesthesia practice, but also in many other medical specialties. Undesired/inadvertent intrathecal injections (UII) are generally rare. There is tremendous variation in reported inadvertent administrations via an intrathecal route in the literature, mainly as individual cases and very small case-series reports. This review aims to identify potential sources of UII, its clinical presentations, and appropriate management. The inadvertent injectants are classified as anesthetic agents and pain medicines, chemotherapeutics, radiological contrast agents, antibiotics and corticosteroids, and miscellaneous chemical agents such as tranexamic acid. The clinical effects of UII are dependent upon inadvertent injectant(s) and dose being administered intrathecally, and can range from no adverse effect to profound neurological consequences and/or death. Prompt cerebrospinal fluid (CSF) lavage and cardiopulmonary support seem to be the mainstay of treatment. If serious consequences are anticipated, CSF lavage could be lifesaving. This review additionally provides some options for comprehensive management and preventing strategies.

Water network-mediated, electron-induced proton transfer in [C5H5N ⋠(H2O)n](-) clusters.

The role of proton-assisted charge accommodation in electron capture by a heterocyclic electron scavenger is investigated through theoretical analysis of the vibrational spectra of cold, gas phase [Py ⋅ (H2O)n=3-5](-) clusters. These radical anions are formed when an excess electron is attached to water clusters containing a single pyridine (Py) molecule in a supersonic jet ion source. Under these conditions, the cluster ion distribution starts promptly at n = 3, and the photoelectron spectra, combined with vibrational predissociation spectra of the Ar-tagged anions, establish that for n > 3, these species are best described as hydrated hydroxide ions with the neutral pyridinium radical, PyH((0)), occupying one of the primary solvation sites of the OH(-). The n = 3 cluster appears to be a special case where charge localization on Py and hydroxide is nearly isoenergetic, and the nature of this species is explored with ab initio molecular dynamics calculations of the trajectories that start from metastable arrangements of the anion based on a diffuse, essentially dipole-bound electron. These calculations indicate that the reaction proceeds via a relatively slow rearrangement of the water network to create a favorable hydration configuration around the water molecule that eventually donates a proton to the Py nitrogen atom to yield the product hydroxide ion. The correlation between the degree of excess charge localization and the evolving shape of the water network revealed by this approach thus provides a microscopic picture of the "solvent coordinate" at the heart of a prototypical proton-coupled electron transfer reaction.

Glutamate quantification in patients with supratentorial gliomas using chemical shift imaging.

This study aimed to evaluate and validate chemical shift imaging (CSI) for in vivo glutamate (Glu) quantification in patients with supratentorial gliomas. If validated, CSI could become an extremely useful tool to investigate metabolic dysfunction of Glu in excitotoxic neuropathologies. Quantitative CSI estimates of Glu concentrations were compared with known concentrations of Glu in aqueous phantom solutions. Forty-one patients with known or likely supratentorial gliomas underwent preoperative CSI. The spectra obtained were analyzed for Glu concentrations and Glu to creatine (Cr) ratios. These in vivo measurements were correlated against ex vivo Glu content quantified by high performance liquid chromatography (HPLC) measured in 65 resected brain tumor and peritumoral brain specimens. For the phantom solutions the CSI estimates of Glu concentration and the Glu/Cr ratios were highly correlated with known Glu concentration (r² = 0.95, p = 0.002, and r² = 0.97, p < 0.0001, respectively). There was a modest, but statistically significant, correlation between the ex vivo measured Glu and in vivo spectroscopic Glu concentration (r² = 0.22, p = 0.04) and ratios of Glu to Cr (r² = 0.30, p = 0.002). Quantitative measurement of Glu content is feasible in patients with supratentorial gliomas using CSI. The in vitro and in vivo results suggest that this has the potential to be a reliable quantitative imaging assay for brain tumor patients. This may have wide clinical research applications in a number of neurological disorders where Glu excitotoxicity and metabolic dysfunction are known to play a role in pathogenesis, including tumor associated epilepsy, epilepsy, stroke and neurotrauma.

How do men and women define sexual desire and sexual arousal?

The purpose of this study was to understand how men and women define sexual desire and sexual arousal and how they distinguish between the two. The authors conducted 32 semi-structured interviews with individuals in South East England, using a purposive sampling strategy to maximize the variation in experience of sexual function across the group. The authors identified three criteria that participants used to define and distinguish between desire and arousal: the sequence in which they occurred; whether the mind or the body (or both) were engaged; and the extent to which feelings of desire or arousal were responsive (in response to person or stimulus) and motivational (oriented toward a goal). Most participants attempted to distinguish between desire and arousal when prompted, but often with difficulty. Participants commonly felt that desire preceded arousal; some felt that desire was "mind" and arousal "body"; and many felt that both desire and arousal were responsive and motivational. However, the authors identified numerous times when these distinctions were reversed or the differences between terms were blurred. The results support recent proposals to merge the two diagnostic categories of female sexual arousal disorder and hyposexual desire disorder into a single diagnostic category.

Age-dependent responsiveness of human female bone cells to vitamin D analog and PTH.

Vitamin D less-calcemic analog JKF 1624 F2-2 (JKF) and PTH 1-34 stimulate in human female cultured osteoblasts (Ob) DNA synthesis (DNA), creatine kinase specific activity (CK), 1α, 25 vitamin D hydroxylase mRNA (1OHase) expression and 1,25(OH)2D3 (1,25) production, estrogen receptors (ER) mRNA expression and intracellular and membranal estrogen binding. In the present study, cultured Ob from different ages were subjected to hormonal stimulations and analyzed for different parameters. We found: 1) ERα expression is higher and ERß expression is lower in pre-meno - pausal Ob (prOb), with similar intracellular and membranal binding. 2) JKF and PTH up-regulated ERα and JKF downregulated ERß in both Ob, while PTH stimulated it in post- (poOb) and inhibited it in prOb. 3) There is higher expression of 1OHase mRNA in prOb, but 1,25 production is similar. Both parameters were hormonally stimulated to higher extent in prOb. 4) Ob express 12 and 15 lipoxygenase (LO) mRNA and produce 12- and 15-hydroxyeicosatetraenoic acid (H). 12LO expression is higher and 15LO is lower in prOb, while 12H is higher in prOb and 15H is similar in both. JKF inhibited 12LO expression in prOb and stimulated in poOb, whereas PTH stimulated it to higher extent in prOb. JKF stimulated and PTH inhibited 15LO expression in both; 12 and 15H were stimulated by both hormones in both Ob. 5. PTH and JKF stimulated DNA and CK in both Ob. In conclusion Ob demonstrate some age-dependent response to calciotrophic hormones, but the mechanism and beneficial outcome for human is unclear.

Wide variation in pre-procedural blood product transfusion practices in cirrhosis: a national multidisciplinary survey.

BACKGROUND AND AIMS: Recent guidelines recognize the limitations of standard coagulation tests in predicting bleeding and guiding pre-procedural blood component prophylaxis in cirrhosis. It is unclear whether these recommendations are reflected in clinical practice. We performed a nationwide survey to investigate pre-procedural transfusion practices and opinions of key health care stakeholders involved in managing cirrhosis. METHODS: We designed a 36-item multiple-choice questionnaire to investigate the international normalized ratio and platelet cutoffs utilized to guide pre-procedural transfusion of fresh frozen plasma and platelets in patients with cirrhosis undergoing a range of low and high-risk invasive procedures. Eighty medical colleagues from all mainland States involved in managing patients with cirrhosis were invited by email to participate. RESULTS: Overall, 48 specialists across Australia completed the questionnaire: 21 gastroenterologists, 22 radiologists, and 5 hepatobiliary surgeons. 50% of respondents reported that their main workplace did not have written guidelines relating to pre-procedural blood component prophylaxis in patients with cirrhosis. There was marked variation in routine prophylactic transfusion practices across institutions for the different procedures and international normalized ratio and platelet cutoffs. This variation was present both within and between specialty groups and held for both low and high-risk procedures. For scenarios where the platelet count was ≤ 50 × 109/L, 61% of respondents stated that prophylactic platelet transfusions would be given before low-risk and 62% before high-risk procedures at their center. For scenarios where the international normalized ratio was ≥2, 46% of respondents stated that prophylactic fresh frozen plasma would be routinely given before low-risk procedures and 74% before high-risk procedures. CONCLUSION: Our survey reveals significant heterogeneity of pre-procedural prophylactic transfusion practices in patients with cirrhosis and discrepancies between guidelines and clinical practice.

Quantum mechanical study of sulfuric acid hydration: atmospheric implications.

The role of the binary nucleation of sulfuric acid in aerosol formation and its implications for global warming is one of the fundamental unsettled questions in atmospheric chemistry. We have investigated the thermodynamics of sulfuric acid hydration using ab initio quantum mechanical methods. For H(2)SO(4)(H(2)O)(n) where n = 1-6, we used a scheme combining molecular dynamics configurational sampling with high-level ab initio calculations to locate the global and many low lying local minima for each cluster size. For each isomer, we extrapolated the Møller-Plesset perturbation theory (MP2) energies to their complete basis set (CBS) limit and added finite temperature corrections within the rigid-rotor-harmonic-oscillator (RRHO) model using scaled harmonic vibrational frequencies. We found that ionic pair (HSO(4)(-)·H(3)O(+))(H(2)O)(n-1) clusters are competitive with the neutral (H(2)SO(4))(H(2)O)(n) clusters for n ≥ 3 and are more stable than neutral clusters for n ≥ 4 depending on the temperature. The Boltzmann averaged Gibbs free energies for the formation of H(2)SO(4)(H(2)O)(n) clusters are favorable in colder regions of the troposphere (T = 216.65-273.15 K) for n = 1-6, but the formation of clusters with n ≥ 5 is not favorable at higher (T > 273.15 K) temperatures. Our results suggest the critical cluster of a binary H(2)SO(4)-H(2)O system must contain more than one H(2)SO(4) and are in concert with recent findings (1) that the role of binary nucleation is small at ambient conditions, but significant at colder regions of the troposphere. Overall, the results support the idea that binary nucleation of sulfuric acid and water cannot account for nucleation of sulfuric acid in the lower troposphere.

Stargazin and AMPA receptor membrane expression is increased in the somatosensory cortex of Genetic Absence Epilepsy Rats from Strasbourg.

Absence-like seizures in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model are believed to arise in hyperexcitable somatosensory cortical neurons, however the cellular basis of this increased excitability remains unknown. We have previously shown that expression of the Transmembrane AMPA receptor Regulatory Protein (TARP), stargazin, is elevated in the somatosensory cortex of GAERS. TARPs are critical regulators of the trafficking and function of AMPA receptors. Here we examine the developmental expression of stargazin and the impact this may have on AMPA receptor trafficking in the GAERS model. We show that elevated stargazin in GAERS is associated with an increase in AMPA receptor proteins, GluA1 and GluA2 in the somatosensory cortex plasma membrane of adult epileptic GAERS. Elevated stargazin expression is not seen in the epileptic WAG/Rij rat, which is a genetically distinct but phenotypically similar rat model also manifesting absence seizures, indicating that the changes seen in GAERS are unlikely to be a secondary consequence of the seizures. In juvenile (6 week old) GAERS, at the age when seizures are just starting to be expressed, there is elevated stargazin mRNA, but not protein expression for stargazin or the AMPA receptor subunits. In neonatal (7 day old) pre-epileptic GAERS there was no alteration in stargazin mRNA expression in any brain region examined. These data demonstrate that stargazin and AMPA receptor membrane targeting is altered in GAERS, potentially contributing to hyperexcitability in somatosensory cortex, with a developmental time course that would suggest a pathophysiological role in the epilepsy phenotype.

Benchmark structures and binding energies of small water clusters with anharmonicity corrections.

For (H(2)O)(n) where n = 1-10, we used a scheme combining molecular dynamics sampling with high level ab initio calculations to locate the global and many low lying local minima for each cluster. For each isomer, we extrapolated the RI-MP2 energies to their complete basis set limit, included a CCSD(T) correction using a smaller basis set and added finite temperature corrections within the rigid-rotor-harmonic-oscillator (RRHO) model using scaled and unscaled harmonic vibrational frequencies. The vibrational scaling factors were determined specifically for water clusters by comparing harmonic frequencies with VPT2 fundamental frequencies. We find the CCSD(T) correction to the RI-MP2 binding energy to be small (<1%) but still important in determining accurate conformational energies. Anharmonic corrections are found to be non-negligble; they do not alter the energetic ordering of isomers, but they do lower the free energies of formation of the water clusters by as much as 4 kcal/mol at 298.15 K.

Population genetic analysis of Tomato spotted wilt virus on peanut in North Carolina and Virginia.

Exploring the genetic diversity and evolutionary history of plant viruses is critical to understanding their ecology and epidemiology. In this study, maximum-likelihood and population genetics-based methods were used to investigate the population structure, genetic diversity, and sources of genetic variation in field isolates of Tomato spotted wilt virus (TSWV) from peanut in North Carolina and Virginia. Selected regions of the nucleocapsid, movement, and RNA-dependent RNA polymerase genes were amplified and sequenced to identify haplotypes and infer genetic relationships between isolates of TSWV with heuristic methods. The haplotype structure of each locus consisted of 1 or 2 predominant haplotypes and >100 haplotypes represented by a single isolate. No specific haplotypes were associated with geographic area, peanut cultivar, or year of isolation. The population was panmictic at the regional level and high levels of genetic diversity were observed among isolates. There was evidence for positive selection on single amino acids in each gene on a background of predominant purifying selection acting upon each locus. The results of compatibility analyses and the persistence of specific gene sequences in isolates collected over three field seasons suggest that recombination was occurring in the population. Estimates of the population mutation rate suggest that mutation has had a significant effect on the shaping of this population and, together with purifying selection, these forces have been the predominant evolutionary forces influencing the TSWV population in peanut in North Carolina and Virginia.

Long-term effects of dihydrotestosterone treatment on prostate growth in healthy, middle-aged men without prostate disease: a randomized, placebo-controlled trial.

BACKGROUND: Benign prostatic hypertrophy increases with age and can result in substantially decreased quality of life for older men. Surgery is often required to control symptoms. It has been hypothesized that long-term administration of a nonamplifiable pure androgen might decrease prostate growth, thereby decreasing or delaying the need for surgical intervention. OBJECTIVE: To test the hypothesis that dihydrotestosterone (DHT), a nonamplifiable and nonaromatizable pure androgen, reduces late-life prostate growth in middle-aged men. DESIGN: Randomized, placebo-controlled, parallel-group trial. (Australian New Zealand Clinical Trials Registry number: ACTRN12605000358640) SETTING: Ambulatory care research center. PARTICIPANTS: Healthy men (n = 114) older than 50 years without known prostate disease. INTERVENTION: Transdermal DHT (70 mg) or placebo gel daily for 2 years. MEASUREMENTS: Prostate volume was measured by ultrasonography; bone mineral density (BMD) and body composition were measured by dual-energy x-ray absorptiometry; and blood samples and questionnaires were collected every 6 months, with data analyzed by mixed-model analysis for repeated measures. RESULTS: Over 24 months, there was an increase in total (29% [95% CI, 23% to 34%]) and central (75% [CI, 64% to 86%]; P < 0.01) prostate volume and serum prostate-specific antigen level (15% [CI, 6% to 24%]) with time on study, but DHT had no effect (P > 0.2). Dihydrotestosterone treatment decreased spinal BMD (1.4% [CI, 0.6% to 2.3%]; P < 0.001) at 24 months but not hip BMD (P > 0.2) and increased serum aminoterminal propeptide of type I procollagen in the second year of the study compared with placebo. Dihydrotestosterone increased serum DHT levels and its metabolites (5α-androstane-3α,17ß-diol and 5α-androstane-3ß,17ß-diol) and suppressed serum testosterone, estradiol, luteinizing hormone, and follicle-stimulating hormone levels. Dihydrotestosterone increased hemoglobin levels (7% [CI, 5% to 9%]), serum creatinine levels (9% [CI, 5% to 11%]), and lean mass (2.4% [CI, 1.6% to 3.1%) but decreased fat mass (5.2% [CI, 2.6% to 7.7%]) (P <0.001 for all). Protocol-specific discontinuations due to DHT were asymptomatic increased hematocrit (n = 8), which resolved after stopping treatment, and increased prostate-specific antigen levels (n = 3; none with prostate cancer) in the DHT group. No serious adverse effects due to DHT occurred. LIMITATION: Negative findings on prostate growth cannot exclude adverse effects on the natural history of prostate cancer. CONCLUSION: Dihydrotestosterone treatment for 24 months has no beneficial or adverse effect on prostate growth but causes a decrease in spinal but not hip BMD. These findings have important implications for the wider use of nonsteroidal pure androgens in older men. PRIMARY FUNDING SOURCE: BHR Pharma.

Accurate predictions of water cluster formation, (H2O)(n=2-10).

An efficient mixed molecular dynamics/quantum mechanics model has been applied to the water cluster system. The use of the MP2 method and correlation consistent basis sets, with appropriate correction for BSSE, allows for the accurate calculation of electronic and free energies for the formation of clusters of 2-10 water molecules. This approach reveals new low energy conformers for (H(2)O)(n=7,9,10). The water heptamer conformers comprise five different structural motifs ranging from a three-dimensional prism to a quasi-planar book structure. A prism-like structure is favored energetically at low temperatures, but a chair-like structure is the global Gibbs free energy minimum past 200 K. The water nonamers exhibit less complexity with all the low energy structures shaped like a prism. The decamer has 30 conformers that are within 2 kcal/mol of the Gibbs free energy minimum structure at 298 K. These structures are categorized into four conformer classes, and a pentagonal prism is the most stable structure from 0 to 320 K. Results can be used as benchmark values for empirical water models and density functionals, and the method can be applied to larger water clusters.

The Role of Laparoscopic Cholecystectomy After Severe and/or Necrotic Pancreatitis in the Setting of Modern Minimally Invasive Management of Pancreatic Necrosis.

OBJECTIVES: The trend toward minimally invasive procedures (MIP) in necrotizing pancreatitis is increasing. The optimal timing and technique of cholecystectomy in severe/necrotizing pancreatitis is unclear. This study aims to determine the role of laparoscopic cholecystectomy after severe/necrotizing pancreatitis in the context of MIP. METHODS: Retrospective analysis of a prospective database was performed for consecutive patients after cholecystectomy for gallstone pancreatitis between January 2011 and January 2018 at Monash Health, Melbourne, Australia. RESULTS: Three hundred fifty-five patients with gallstone pancreatitis underwent laparoscopic cholecystectomy with 2 conversions. Patients with severe pancreatitis were older (P = 0.002), with a more even sex distribution when compared with mild pancreatitis. Females predominated in the mild pancreatitis group.Patients with moderate/severe pancreatitis (P = 0.002) and necrosis (P > 0.001) were more likely to have delayed cholecystectomy compared with mild pancreatitis. There was no increase in biliary presentations while awaiting cholecystectomy. Length of stay for patients with severe/necrotizing pancreatitis (P = 0.001) was increased, surgical complications appeared similar. CONCLUSIONS: Laparoscopic cholecystectomy can be performed safely and effectively for pancreatitis, irrespective of severity. The paradigm shift in the management of severe necrotizing pancreatitis away from open necrosectomy toward MIP can be extended to encompass laparoscopic cholecystectomy.

Genetic absence epilepsy rats from Strasbourg have increased corticothalamic expression of stargazin.

Stargazin is membrane bound protein involved in trafficking, synapse anchoring and biophysical modulation of AMPA receptors. A quantitative trait locus in chromosome 7 containing the stargazin gene has been identified as controlling the frequency and duration of absence seizures in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS). Furthermore, mutations in this gene result in the Stargazer mouse that displays an absence epilepsy phenotype. GAERS stargazin mRNA expression is increased 1.8 fold in the somatosensory cortex and by 1.3 fold in the thalamus. The changes were present before and after the onset of absence seizures indicating that increases are not a secondary consequence of the seizures. Stargazin protein expression was also significantly increased in the somatosensory cortex after the onset of spontaneous seizures. The results are of significant importance beyond the GAERS model, as they are the first to show that an increase in stargazin expression may be pro-epileptic.