Predicting mortality from acetaminophen poisoning shortly after hospital presentation.

AIMS: Early identification of patients likely to die after acetaminophen (APAP) poisoning remains challenging. We sought to compare the sensitivity and time to fulfilment (latency) of established prognostic criteria. METHODS: Three physician toxicologists independently classified every in-hospital death associated with APAP overdose from eight large Canadian cities over three decades using the Relative Contribution to Fatality scale from the American Association of Poison Control Centres. The sensitivity and latency were calculated for each of the following criteria: King's College Hospital (KCH), Model for End Stage Liver Disease (MELD) ≥33, lactate ≥3.5 mmol/L, phosphate ≥1.2 mmol/L 48+ hours post-ingestion, as well as combinations thereof. RESULTS: A total of 162 in-hospital deaths were classified with respect to APAP as follows: 26 Undoubtedly, 40 Probably, 27 Contributory, 14 Probably not, 25 Clearly not, and 30 Unknown. Cases from the first three classes (combined into n = 93 "APAP deaths") typically presented with supratherapeutic APAP concentrations, hepatotoxicity, acidaemia, coagulopathy and/or encephalopathy, and began antidotal treatment a median of 12 hours (IQR 3.4-30 h) from the end of ingestion. Among all patients deemed "APAP deaths", meeting either KCH or lactate criteria demonstrated the highest sensitivity (94%; 95% CI 86-98%), and the shortest latency from hospital arrival to criterion fulfilment (median 4.2 h; IQR 1.0-16 h). In comparison, the MELD criterion demonstrated a substantially lower sensitivity (55%; 43-66%) and longer latency (52 h; 4.4-∞ h, where "∞" denotes death prior to criterion becoming positive). CONCLUSIONS: Meeting either KCH or serum lactate criteria identifies most patients who die from acetaminophen poisoning at or shortly after hospital presentation.

Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-Related Cancer in Women: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.

Importance: Pathogenic mutations in breast cancer susceptibility genes BRCA1 and BRCA2 increase risks for breast, ovarian, fallopian tube, and peritoneal cancer in women; interventions reduce risk in mutation carriers. Objective: To update the 2013 US Preventive Services Task Force review on benefits and harms of risk assessment, genetic counseling, and genetic testing for BRCA1/2-related cancer in women. Data Sources: Cochrane libraries; MEDLINE, PsycINFO, EMBASE (January 1, 2013, to March 6, 2019, for updates; January 1, 1994, to March 6, 2019, for new key questions and populations); reference lists. Study Selection: Discriminatory accuracy studies, randomized clinical trials (RCTs), and observational studies of women without recently diagnosed BRCA1/2-related cancer. Data Extraction and Synthesis: Data on study methods, setting, population characteristics, eligibility criteria, interventions, numbers enrolled and lost to follow-up, outcome ascertainment, and results were abstracted. Two reviewers independently assessed study quality. Main Outcomes and Measures: Cancer incidence and mortality; discriminatory accuracy of risk assessment tools for BRCA1/2 mutations; benefits and harms of risk assessment, genetic counseling, genetic testing, and risk-reducing interventions. Results: For this review, 103 studies (110 articles; N = 92 712) were included. No studies evaluated the effectiveness of risk assessment, genetic counseling, and genetic testing in reducing incidence and mortality of BRCA1/2-related cancer. Fourteen studies (n = 43 813) of 8 risk assessment tools to guide referrals to genetic counseling demonstrated moderate to high accuracy (area under the receiver operating characteristic curve, 0.68-0.96). Twenty-eight studies (n = 8060) indicated that genetic counseling was associated with reduced breast cancer worry, anxiety, and depression; increased understanding of risk; and decreased intention for testing. Twenty studies (n = 4322) showed that breast cancer worry and anxiety were higher after testing for women with positive results and lower for others; understanding of risk was higher after testing. In 8 RCTs (n = 54 651), tamoxifen (relative risk [RR], 0.69 [95% CI, 0.59-0.84]; 4 trials), raloxifene (RR, 0.44 [95% CI, 0.24-0.80]; 2 trials), and aromatase inhibitors (RR, 0.45 [95% CI, 0.26-0.70]; 2 trials) were associated with lower risks of invasive breast cancer compared with placebo; results were not specific to mutation carriers. Mastectomy was associated with 90% to 100% reduction in breast cancer incidence (6 studies; n = 2546) and 81% to 100% reduction in breast cancer mortality (1 study; n = 639); oophorectomy was associated with 69% to 100% reduction in ovarian cancer (2 studies; n = 2108); complications were common with mastectomy. Conclusions and Relevance: Among women without recently diagnosed BRCA1/2-related cancer, the benefits and harms of risk assessment, genetic counseling, and genetic testing to reduce cancer incidence and mortality have not been directly evaluated by current research.

Diagnostic Methods for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review for a National Institutes of Health Pathways to Prevention Workshop.

BACKGROUND: The diagnosis of myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is based on clinical criteria, yet there has been no consensus regarding which set of criteria best identifies patients with the condition. The Institute of Medicine has recently proposed a new case definition and diagnostic algorithm. PURPOSE: To review methods to diagnose ME/CFS in adults and identify research gaps and needs for future research. DATA SOURCES: MEDLINE, PsycINFO, and Cochrane databases (January 1988 to September 2014); clinical trial registries; and reference lists. STUDY SELECTION: English-language studies describing methods of diagnosis of ME/CFS and their accuracy. DATA EXTRACTION: Data on participants, study design, analysis, follow-up, and results were extracted and confirmed. Study quality was dual-rated by using prespecified criteria, and discrepancies were resolved through consensus. DATA SYNTHESIS: Forty-four studies met inclusion criteria. Eight case definitions have been used to define ME/CFS; a ninth, recently proposed by the Institute of Medicine, includes principal elements of previous definitions. Patients meeting criteria for ME represent a more symptomatic subset of the broader ME/CFS population. Scales rating self-reported symptoms differentiate patients with ME/CFS from healthy controls under study conditions but have not been evaluated in clinically undiagnosed patients to determine validity and generalizability. LIMITATIONS: Studies were heterogeneous and were limited by size, number, applicability, and methodological quality. Most methods were tested in highly selected patient populations. CONCLUSION: Nine sets of clinical criteria are available to define ME/CFS, yet none of the current diagnostic methods have been adequately tested to identify patients with ME/CFS when diagnostic uncertainty exists. More definitive studies in broader populations are needed to address these research gaps.

Treatment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review for a National Institutes of Health Pathways to Prevention Workshop.

BACKGROUND: Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is a debilitating multisystem condition affecting more than 1 million adults in the United States. PURPOSE: To determine benefits and harms of treatments for adults with ME/CFS and identify future research needs. DATA SOURCES: MEDLINE, PsycINFO, and Cochrane databases (January 1988 to September 2014); clinical trial registries; reference lists; and manufacturer information. STUDY SELECTION: English-language randomized trials of the effectiveness and adverse effects of ME/CFS treatments. DATA EXTRACTION: Data on participants, study design, analysis, follow-up, and results were extracted and confirmed. Study quality was dual-rated by using prespecified criteria; discrepancies were resolved through consensus. DATA SYNTHESIS: Among 35 treatment trials enrolling participants primarily meeting the 1994 Centers for Disease Control and Prevention and Oxford case definitions of CFS, the immune modulator rintatolimod improved some measures of exercise performance compared with placebo in 2 trials (low strength of evidence). Trials of galantamine, hydrocortisone, IgG, valganciclovir, isoprinosine, fluoxetine, and various complementary medicines were inconclusive (insufficient evidence). Counseling therapies and graded exercise therapy compared with no treatment, relaxation, or support improved fatigue, function, global improvement, and work impairment in some trials; counseling therapies also improved quality of life (low to moderate strength of evidence). Harms were rarely reported across studies (insufficient evidence). LIMITATION: Trials were heterogeneous and were limited by size, number, duration, applicability, and methodological quality. CONCLUSION: Trials of rintatolimod, counseling therapies, and graded exercise therapy suggest benefit for some patients meeting case definitions for CFS, whereas evidence for other treatments and harms is insufficient. More definitive studies comparing participants meeting different case definitions, including ME, and providing subgroup analysis are needed to fill research gaps.

Femoral volumetric bone density, geometry, and strength in relation to 25-hydroxy vitamin D in older men.

Low serum 25-hydroxy vitamin D (25(OH)D) concentrations are associated with increased hip fracture risk and decreased femoral areal bone mineral density (BMD) among elderly men. Structural dimensions of the proximal femur and volumetric BMD in cortical and trabecular compartments are also associated with hip fracture risk. However, associations of volumetric BMD or structural dimensions with serum 25(OH)D concentrations among older men remain unclear. In a random sample of 1608 men aged ≥65 years from the Osteoporotic Fractures in Men Study (MrOS), baseline serum 25(OH)D concentrations were measured by liquid chromatography/mass spectrometry assays. Femoral neck geometry and volumetric BMD derived from quantitative computed tomography included integral, cortical, and trabecular volumetric BMD; cross-sectional area; integral and cortical volume; and cortical volume as a percent of integral volume. We studied 888 men with vitamin D, parathyroid hormone (PTH), femoral neck geometry, and BMD measures. Whole-bone femoral strength and load-strength ratio from finite element (FE) analysis were also available for 356 men from this sample. Multivariable linear regression was used to estimate least square means of each femoral measure within quartiles of 25(OH)D adjusted for age, race, body mass index, height, latitude, and season of blood draw. Tests of linear trend in the means were performed across increasing quartile of serum 25(OH)D levels. Mean cortical volume (p trend = 0.006) and cortical volume as a percent of integral volume (p trend < 0.001) increased across increasing quartile of 25(OH)D level. However, overall femoral neck size (area and integral volume) did not vary by 25(OH)D level. Femoral neck volumetric BMD measures increased in a graded manner with higher 25(OH)D levels (p trend < 0.001). Femoral strength, but not load-strength ratio, increased with increasing 25(OH)D. Adjustment for PTH did not materially change these associations. We conclude that in older men, higher levels of endogenous 25(OH)D may increase whole-bone strength by increasing femoral volumetric BMD and cortical volume.

Observing trainee encounters using a one-way mirror.

BACKGROUND: Direct observation of patient encounters is a key component of evaluating residents during training, but there are scarce data on the various methods of observation. AIM: To implement a novel method for direct observation of out-patient encounters via a one-way mirror in an internal medicine resident practice, and to assess the feasibility and acceptance of this method. METHODS: Each selected resident-patient encounter was directly observed by a preceptor through a one-way mirror. The preceptor provided feedback to the resident at the conclusion of each encounter. A post-visit survey assessed resident satisfaction and comfort with this method of observation. RESULTS: Using a one-way mirror was a feasible method of observation. Fifty residents had a clinic visit that was directly observed, and 42 (84%) completed the post-visit survey. Residents reported that they preferred direct observation through a one-way mirror compared with other methods, including videotaped encounters or having a preceptor physically present in the room. They also felt that having a preceptor observing through the one-way mirror had no negative effect on the clinic visit. Direct observation of patient encounters is a key component of evaluating residents CONCLUSIONS: Direct observation through a one-way mirror is a viable method in the out-patient setting, and might be preferable for evaluating certain skills.

Diagnosis and Treatment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

OBJECTIVES: This systematic review summarizes research on methods of diagnosing myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and benefits and harms of multiple medical and nonmedical treatments. It identifies evidence gaps and limitations to inform future research. DATA SOURCES: Searches of electronic databases included MEDLINE® (1988 to September 2014), PsycINFO® (1988 to September 2014), and the Cochrane Library (through the third quarter of 2014). The searches were supplemented by reviewing reference lists, seeking suggestions from reviewers, and requesting scientific information from drug and device manufacturers. REVIEW METHODS: Two investigators reviewed abstracts and full-text articles for inclusion based on predefined criteria. Discrepancies were resolved through discussion and consensus, with a third investigator making the final decision. RESULTS: A total of 6,175 potentially relevant articles were identified, 1,069 were selected for full-text review, and 71 studies in 81 publications were included (36 observational studies on diagnosis and 35 trials of treatments). Eight case definitions have been used to define ME/CFS; those for ME, requiring the presence of postexertional malaise, represent a more symptomatic subset of the broader ME/CFS population. Researchers are unable to determine differences in accuracy between case definitions because there is no universally accepted reference standard for diagnosing ME/CFS. The Oxford criteria are the least restrictive and include patients who would not otherwise meet criteria for ME/CFS. Self-reported symptom scales may differentiate ME/CFS patients from healthy controls but have not been adequately evaluated to determine validity and generalizability in large populations with diagnostic uncertainty. Fourteen studies reported the consequences of diagnosis, including perceived stigma and the burden of misdiagnosis, as well as feelings of legitimacy upon receiving the diagnosis of ME/CFS.Of the 35 trials of treatment, rintatolimod compared with placebo improved measures of exercise performance; counseling therapies and graded exercise treatment (GET) compared with no treatment, relaxation, or support improved fatigue, function, and quality of life, and counseling therapies also improved employment outcomes. Other treatments either provided no benefit or results were insufficient to draw conclusions. GET was associated with higher numbers of reported adverse events compared with counseling therapies or controls. Harms were generally inadequately reported across trials. LIMITATIONS: Diagnostic methods were studied only in highly selected patient populations. Treatment trials were limited in number and had small sample sizes and methodological shortcomings. CONCLUSIONS: None of the current diagnostic methods have been adequately tested to identify patients with ME/CFS when diagnostic uncertainty exists. Rintatolimod improves exercise performance in some patients (low strength of evidence), while counseling therapies and GET have broader benefit but have not been adequately tested in more disabled populations (low to moderate strength of evidence). Other treatments and harms have been inadequately studied (insufficient evidence). More definitive studies are needed to fill the many research gaps in diagnosing and treating ME/CFS.

Normocalcemic hyperparathyroidism and hypoparathyroidism in two community-based nonreferral populations.

CONTEXT: Normocalcemic primary hyperparathyroidism is typically identified after referral to a specialty clinic. At diagnosis, patients demonstrate features seen in hypercalcemic primary hyperparathyroidism. Normocalcemic hypoparathyroidism has been discovered after hypocalcemia unmasked after bisphosphonate administration. OBJECTIVE: We hypothesized that screening unselected, nonreferral populations, such as The Osteoporotic Fractures in Men (MrOS) study and Dallas Heart Study (DHS), would identify asymptomatic subjects with normocalcemic hyperparathyroidism and hypoparathyroidism. METHODS: Normocalcemic hyperparathyroidism was defined as serum PTH greater than the upper reference range with normal albumin-adjusted serum calcium, excluding common secondary causes (renal failure [estimated glomerular filtration rate <60 mL/min], 25-hydroxyvitamin D <20 ng/mL, and thiazide use), and normocalcemic hypoparathyroidism as PTH below the reference range with normocalcemia. Cross-sectional data were obtained from MrOS, and longitudinal data (baseline and 8 years) from DHS. RESULTS: In 2364 men from MrOS, we identified 9 with normocalcemic hyperparathyroidism (prevalence 0.4%) and 26 with normocalcemic hypoparathyroidism (1.1%). In 3450 men and women from DHS, we identified 108 with normocalcemic hyperparathyroidism (3.1%) and 68 with normocalcemic hypoparathyroidism (1.9%). Of the 108 normocalcemic hyperparathyroid subjects, 64 had follow-up data. Hypercalcemic primary hyperparathyroidism developed in 1 subject whereas 13 (0.6% of the follow-up cohort) showed persistently elevated PTH levels with normocalcemia. Of the 26 normocalcemic hypoparathyroid subjects with follow-up data, none developed overt hypoparathyroidism and 2 (0.09%) had persistent evidence of normocalcemic hypoparathyroidism. CONCLUSIONS: This study documents normocalcemic primary hyperparathyroidism and hypoparathyroidism identified among community-dwelling individuals. Larger studies are needed to determine the true prevalence and natural history of these parathyroid disorders.

Emergency medicine ultrasonography in rural communities.

INTRODUCTION: The Canadian Association of Emergency Physicians (CAEP) published a position statement in 2006 encouraging immediate access to emergency medicine ultrasonography (EMUS) 24 hours a day, 7 days a week. However, barriers to advanced imaging care still exist in many rural hospitals. Our study investigated the current availability of EMUS in rural communities and physicians' ability to use this technology. METHODS: A literature review and interviews with rural physicians were conducted in the summer of 2010 to design a questionnaire focusing on EMUS. The survey was then sent electronically or via regular mail in November 2010 to all Ontario physicians self-identified as "rural." Descriptive statistics and the Fisher exact test were used to analyze the data. RESULTS: A total of 207 rural physicians responded to the survey (response rate 28.6%). Of the respondents, 70.9% were male, median age was 49 years and median year of graduation was 1988. The respondents had been in practice for a median of 20 years and had been in their present community for a median of 15 years. More than two-thirds of physicians (69.5%) practised in communities with populations of less than 10 000. Nearly three-quarters (72.6%) worked in a rural emergency department (ED). Almost all (96.9%) reported having access to ultrasonography in the hospital. However, only 60.6% had access to ultrasonography in the ED. Less than half (44.4%) knew how to perform ultrasonography, with 77.3% citing lack of training. Of those using EMUS, 32.5% were using it at least once per shift. The most common reason to use EMUS was to rule out abdominal aortic aneurysm (58.3%). Most respondents (71.5%) agreed or strongly agreed that EMUS is a skill that all rural ED physicians should have. CONCLUSION: Patients in many rural EDs do not have immediate access to EMUS, as advocated by CAEP. This gap in care needs to be addressed to ensure that all patients, no matter where they live, have access to this proven imaging modality.

The expression of self-incompatibility in angiosperms is bimodal.

Self-incompatibility is expressed by nearly one-half of all angiosperms. A large proportion of the remaining species are self-compatible, and they either outcross using various contrivances or self-fertilize to some extent. Because of the common occurrence of populations and individuals with intermediate levels of self-incompatibility, categorization of the expression of self-incompatibility as an approximately binary trait has become controversial. We collect a widely reported index (index of self-incompatibility [ISI]) used to asses the strength and variation of self-incompatibility from over 1200 angiosperm taxa. Its distribution is bimodal and positively associated with outcrossing rate, albeit with a weak relationship within self-compatible taxa. A substantial fraction of species has intermediate mean values of ISI. Their occurrence can be caused by segregating ephemeral self-compatible mutations, averaging artifacts, and experimental biases, in addition to the often invoked stabilizing selection acting on the expression of self-incompatibility. Selection may also generally favor taxa with high ISI values through increased lineage birth and death rates, and it may counter lower level selection advantages within taxa expressing intermediate and low values of ISI. Such a null hypothesis is nearly universally overlooked, despite the fact that it could adequately explain the observed distribution of mating and breeding systems.

Association of intact parathyroid hormone levels with subsequent hip BMD loss: the Osteoporotic Fractures in Men (MrOS) Study.

INTRODUCTION: There is little information on the association between intact PTH (iPTH) and longitudinal changes in bone mineral density (BMD) in older men. This association was evaluated in relation to conditions related to higher iPTH [e.g. decreased renal function, low serum 25-hydroxyvitamin D (25[OH]D)]. METHODS: Eligible men were part of a random sample of 1593 community-dwelling individuals aged 65 yr or older participating in the Osteoporotic Fractures in Men study with baseline iPTH data. Of these, 1227 had at least two BMD measurements at the total hip and femoral neck over a mean follow-up of 4.5 yr. Annualized BMD change across iPTH quartiles was estimated using mixed-effects regression models, adjusting for age, serum calcium, serum 25(OH)D, estimated glomerular filtration rate, and other factors. Splines were used to identify more optimal iPTH thresholds associated with less BMD loss. RESULTS: Among the cohort of 1138 eligible men, men in the highest quartile of iPTH (≥38 pg/ml) lost 0.46% per year at the total hip compared with men in the lowest iPTH quartile who lost 0.22% per year (P = 0.0004). Results were similar at the femoral neck. The association between iPTH and BMD loss was not modified by baseline estimated glomerular filtration rate or 25(OH)D status. Spline results suggested that iPTH levels below 30 pg/ml were more physiologically optimal than higher iPTH values in reducing BMD loss, although an exact threshold for optimal iPTH was not identified. CONCLUSION: Older men with higher iPTH levels had approximately a 2-fold greater rate of BMD loss compared with men with lower iPTH levels, irrespective of estimated glomerular filtration rate and 25(OH)D.

Osteoporosis piece of multi-morbidity puzzle in geriatric care.

Osteoporosis frequently coexists with other chronic diseases and syndromes of aging, and therefore multimorbidity interactions can potentially complicate its evaluation and treatment. This article reviews osteoporosis comorbidity interactions with select common diseases of aging including cardiovascular, neurologic, and geriatric syndromes, and select commonly used medications by older adults. Using depression as a case example, we describe the complex relationship between osteoporosis, mood, and antidepressant medications, and the implications of these interactions for patients and clinicians.

Use of antidepressant medications and risk of fracture in older women.

Use of antidepressant medications has been associated with increased risk of fracture, but prior studies have been limited by incomplete control of confounders or a limited number of fractures. Use of antidepressant medications by 8,217 community-dwelling women aged 69 and older from a population-based prospective cohort study at four US clinical centers was assessed by interview at four examinations over a 10-year period, beginning in 1992-1994. Use was coded as a time-dependent variable. Incident fractures occurring after the initial medication assessment until July 2007 were confirmed by radiographic reports. Potential confounders were included in multivariable models and updated at each follow-up visit. Compared to nonusers of antidepressant medications, women using SSRIs experienced a higher risk of nonspine fracture in age-adjusted models (HR = 1.36, 95% CI 1.11-1.67) and in multivariable models controlling for potential confounders (HR = 1.30, 95% CI 1.04-1.62). SSRI use was not associated with an increased risk of first hip fracture (HR = 1.01, 95% CI 0.71-1.44) but was associated with an increased risk of wrist fracture (HR = 1.54, 95% CI 1.01-2.36). TCA use was associated with an increased risk of nonspine fracture in age-adjusted models, but in multivariable models this risk was attenuated. SSRI use was associated with a higher risk of any nonspine fracture, but not hip fracture, in this cohort of older women. TCA use was associated with a higher risk of nonspine fracture, but this association was in part explained by confounding factors.

Screening for osteoporosis: an update for the U.S. Preventive Services Task Force.

BACKGROUND: This review updates evidence since the 2002 U.S. Preventive Services Task Force recommendation on osteoporosis screening. PURPOSE: To determine the effectiveness and harms of osteoporosis screening in reducing fractures for men and postmenopausal women without known previous fractures; the performance of risk-assessment instruments and bone measurement tests in identifying persons with osteoporosis; optimal screening intervals; and the efficacy and harms of medications to reduce primary fractures. DATA SOURCES: Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews (through the fourth quarter of 2009), MEDLINE (January 2001 to December 2009), reference lists, and Web of Science. STUDY SELECTION: Randomized, controlled trials of screening or medications with fracture outcomes published in English; performance studies of validated risk-assessment instruments; and systematic reviews and population-based studies of bone measurement tests or medication harms. DATA EXTRACTION: Data on patient populations, study design, analysis, follow-up, and results were abstracted, and study quality was rated by using established criteria. DATA SYNTHESIS: Risk-assessment instruments are modest predictors of low bone density (area under the curve, 0.13 to 0.87; 14 instruments) and fractures (area under the curve, 0.48 to 0.89; 11 instruments); simple and complex instruments perform similarly. Dual-energy x-ray absorptiometry predicts fractures similarly for men and women; calcaneal quantitative ultrasonography also predicts fractures, but correlation with dual-energy x-ray absorptiometry is low. For postmenopausal women, bisphosphonates, parathyroid hormone, raloxifene, and estrogen reduce primary vertebral fractures. Trials are lacking for men. Bisphosphonates are not consistently associated with serious adverse events; raloxifene and estrogen increase thromboembolic events; and estrogen causes additional adverse events. LIMITATION: Trials of screening with fracture outcomes, screening intervals, and medications to reduce primary fractures, particularly those enrolling men, are lacking. CONCLUSION: Although methods to identify risk for osteoporotic fractures are available and medications to reduce fractures are effective, no trials directly evaluate screening effectiveness, harms, and intervals. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.

Microfluidic stochastic confinement enhances analysis of rare cells by isolating cells and creating high density environments for control of diffusible signals.

Rare cells can be difficult to analyze because they either occur in low numbers or coexist with a more abundant cell type, yet their detection is crucial for diagnosing disease and maintaining human health. In this tutorial review, we introduce the concept of microfluidic stochastic confinement for use in detection and analysis of rare cells. Stochastic confinement provides two advantages: (1) it separates rare single cells from the bulk mixture and (2) it allows signals to locally accumulate to a higher concentration around a single cell than in the bulk mixture. Microfluidics is an attractive method for implementing stochastic confinement because it provides simple handling of small volumes. We present technologies for microfluidic stochastic confinement that utilize both wells and droplets for the detection and analysis of single cells. We address how these microfluidic technologies have been used to observe new behavior, increase speed of detection, and enhance cultivation of rare cells. We discuss potential applications of microfluidic stochastic confinement to fields such as human diagnostics and environmental testing.

The emerging role of serotonin (5-hydroxytryptamine) in the skeleton and its mediation of the skeletal effects of low-density lipoprotein receptor-related protein 5 (LRP5).

Novel molecular pathways obligatory for bone health are being rapidly identified. One pathway recently revealed involves gut-derived 5-hydroxytryptamine (5-HT) mediation of the complete skeletal effects of low-density lipoprotein receptor-related protein 5 (LRP5). Mounting evidence supports 5-HT as an important regulatory compound in bone with previous evidence demonstrating that bone cells possess functional pathways for responding to 5-HT. In addition, there is growing evidence that potentiation of 5-HT signaling via inhibition of the 5-HT transporter (5-HTT) has significant skeletal effects. The later is clinically significant as the 5-HTT is a popular target of pharmaceutical agents, such as selective serotonin reuptake inhibitors (SSRIs), used for the management of major depressive disorder and other affective conditions. The observation that 5-HT mediates the complete skeletal effects of LRP5 represents a significant paradigm shift from the traditional view that LRP5 located on the cell surface membrane of osteoblasts exerts direct skeletal effects via Wnt/beta-catenin signaling. This paper discusses the mounting evidence for skeletal effects of 5-HT and the ability of gut-derived 5-HT to satisfactorily explain the skeletal effects of LRP5.

Effects of selective serotonin reuptake inhibitors on bone health in adults: time for recommendations about screening, prevention and management?

Evidence regarding a functional serotonin (5-hydroxytryptamine) signaling system in bone has generated considerable recent interest. The specific biochemical nature of serotoninergic pathways and their direct and/or indirect effects on bone metabolism are still unclear. Clinical evidence supports an effect of serotonin and altered serotonin signaling on bone metabolism. Serotonin is involved in the pathophysiology of depression, and therefore studies of depression and antidepressant treatments (as modulators of the serotonin system) are relevant with regard to bone outcomes. Studies on the effect of depression on bone mineral density (BMD) and fractures have been mixed. Studies on the associations between antidepressant use and BMD and/or fractures are more consistent. SSRIs have been associated with lower BMD and increased rates of bone loss, as well as increased rates of fracture after accounting for falls. These studies are limited by confounding because depression is potentially associated with both the outcome of interest (BMD and fracture) and the exposure (SSRIs). With mounting evidence for an effect on bone, this review considers the question of causality and whether selective serotonin reuptake inhibitors should be considered among those medications that contribute to bone loss, and therefore prompt clinicians to evaluate BMD proactively. Future research will be required to confirm the serotoninergic effects on bone and the biochemical pathways involved, and to identify clinical implications for treatment based on this novel pathway.

Male osteoporosis: new insights in an understudied disease.

PURPOSE OF REVIEW: Osteoporosis in men is increasingly recognized as an important health problem. New research contributes to our knowledge of gender differences in osteoporosis risk, diagnosis and management. We undertook this review to summarize recent developments in the field of male osteoporosis. RECENT FINDINGS: The paper reviews recently published studies that reveal new insights into male osteoporosis. It addresses epidemiology, risk factors, use of clinical risk assessment tools, diagnosis and treatment. New data continue to suggest that men have higher mortality rates than women after hip fracture, and that men may experience fractures at higher bone mineral density values than women. Treatments for osteoporosis have been studied mostly in women, but trials including both men and women are now being conducted. Likewise, there are several newer cohorts with bone and fracture outcomes that include men and women. The Osteoporotic Fractures in Men (MrOS) study is the first United States-based cohort to include only men; this study is contributing importantly to our understanding of epidemiology and risk factors for osteoporosis in men. SUMMARY: Men and their physicians should be aware of the risk for osteoporosis and the gender differences that exist within this disease. Further research is needed to continue to understand differences in pathophysiology, epidemiology and risk factors, and to promote appropriate therapies among men.