Therapeutic Potential of Citrulline as an Arginine Supplement: A Clinical Pharmacology Review

Supplemental arginine has shown promise as a safe therapeutic option to improve endogenous nitric oxide (NO) regulation in cardiovascular diseases associated with endothelial dysfunction. L-arginine, an endogenous amino acid, was reported in clinical studies in adults to improve cardiovascular function in hypertension, pulmonary hypertension, pre-eclampsia, angina, and mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. L-citrulline, a natural precursor of L-arginine, is more bioavailable than L-arginine because of hepatic first-pass metabolism avoidance and longer circulation time. Although not yet well studied, arginine/citrulline has immense therapeutic potential in some life-threatening diseases of children. However, optimal clinical development of arginine or citrulline in children is dependent on more information about pharmacokinetics and exposure-response relationships at appropriate ages and under relevant disease states. This article summarizes the pre-clinical and clinical studies of arginine/citrulline in both adults and children, including currently available pharmacokinetic information. The pharmacology of arginine/citrulline is confounded by several patient-specific factors such as baseline variation of arginine/citrulline due to developmental ages and disease states. Currently available pharmacokinetic studies are not enough to inform the optimal design of clinical studies, especially those in children. Successful bench to bedside clinical translation of arginine supplementation awaits information from well-designed pharmacokinetic-pharmacodynamic studies, along with pharmacometric approaches

Oral Drug Dosing Following Bariatric Surgery: General Concepts and Specific Dosing Advice

Bariatric or weight-loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended-release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advice for oral drug therapy after bariatric surgery, implying that a risk assessment on a case-by-case basis is required for each drug

Current use of complementary and conventional medicine for treatment of pediatric patients with gastrointestinal disorders

Infants, children, and adolescents are at risk of experiencing a multitude of gastrointestinal disorders (GID). These disorders can adversely affect the quality of life or be life-threatening. Various interventions that span the conventional and complementary therapeutic categories have been developed. Nowadays, parents increasingly seek complementary options for their children to use concurrently with conventional therapies. Due to the high prevalence and morbidity of diarrhea, constipation, and irritable bowel syndrome (IBS) in children, in this review, we decided to focus on the current state of the evidence for conventional and complementary therapies used for the treatment of these diseases in children. Diarrhea treatment focuses on the identification of the cause and fluid management. Oral rehydration with supplementation of deficient micronutrients, especially zinc, is well established and recommended. Some probiotic strains have shown promise in reducing the duration of diarrhea. For the management of constipation, available clinical trials are insufficient for conclusive recommendations of dietary modifications, including increased use of fruit juice, fiber, and fluid. However, the role of laxatives as conventional treatment is becoming more established. Polyethylene glycol is the most studied, with lactulose, milk of magnesia, mineral oil, bisacodyl, and senna presenting as viable alternatives. Conventional treatments of the abdominal pain associated with IBS are poorly studied in children. Available studies investigating the effectiveness of antidepressants on abdominal pain in children with IBS were inconclusive. At the same time, probiotics and peppermint oil have a fair record of benefits and safety. The overall body of evidence indicates that a careful balance of conventional and complementary treatment strategies may be required to manage gastrointestinal conditions in children

Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics

In December 2016, a panel of experts in microbiology, nutrition and clinical research was convened by the International Scientific Association for Probiotics and Prebiotics to review the definition and scope of prebiotics. Consistent with the original embodiment of prebiotics, but aware of the latest scientific and clinical developments, the panel updated the definition of a prebiotic: a substrate that is selectively utilized by host microorganisms conferring a health benefit. This definition expands the concept of prebiotics to possibly include non-carbohydrate substances, applications to body sites other than the gastrointestinal tract, and diverse categories other than food. The requirement for selective microbiota-mediated mechanisms was retained. Beneficial health effects must be documented for a substance to be considered a prebiotic. The consensus definition applies also to prebiotics for use by animals, in which microbiota-focused strategies to maintain health and prevent disease is as relevant as for humans. Ultimately, the goal of this Consensus Statement is to engender appropriate use of the term ‘prebiotic’ by relevant stakeholders so that consistency and clarity can be achieved in research reports, product marketing and regulatory oversight of the category. To this end, we have reviewed several aspects of prebiotic science including its development, health benefits and legislation

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Development of a HPLC method for the determination of methotrexate (MTX) and MTX-polyglutamates of red blood cells: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Science with Honours at Lincoln University

Methotrexate (MTX) low-dose therapy has been increasingly used for the treatment of patients with rheumatoid arthritis (RA). Patient response to, the drug and development of side effects are poorly understood. There is large a variation in clinical response between patients and this influences the dose requirement. Therefore, there is a need for therapeutic drug monitoring to ascertain clinical efficacy and drug toxicity. Plasma monitoring of MTX is of little value. Drug activity depends on the accumulation of MTX and active metabolites, MTX polyglutamates (glu)s in the cells. MTX(glu)s are retained in red blood cells (RBC) and have a half-life of 4 to 6 weeks. Measuring these metabolites is relevant as a steady RBC MTX and MTX(glu) level can be achieved following 6 to 8 weeks continuous MTX treatment. A simple, rapid high-performance liquid chromatographic (HPLC) assay to determine MTX and MTX(glu)s in RBC is described. After extraction of MTX(glu)s from RBCs, chromatographic separation was achieved using a C₁₈ reversed-phase column, followed by ultraviolet (UV) detection at 254 nm. RBC standards for MTX and MTX(glu)s were linear over the concentration range of 0 - 500 ng/200 μI. The minimum detection limit of MTX and MTX(glu)s was 15.6 ng/200 μI. MTX, MTX(glu)2 & MTX(glu)3 were detected in the RBCs of two out of five patients treated for RA. This method requires further validation, including intra- and inter-day coefficients of variation. This method for the determination of MTX and MTX(glu)s in RBCs would provide clinicians more information on pharmacokinetics of MTX and thus allow them to make better judgement in the clinical evaluation of patients undergoing MTX lowdose therapy