Comparing Effectiveness of a Generic Oral Nutritional Supplement With Specialized Formula in the Treatment of Active Pediatric Crohn's Disease

BACKGROUND

Exclusive enteral nutrition (EEN) is the recommended induction treatment of mild to moderate active pediatric Crohn's disease (CD). This study compared outcomes of 2 proprietary polymeric formulas. Treatment effectiveness was examined along with practical aspects of formula delivery and differences in estimated treatment costs.

METHODS

Data were retrospectively collected from patients with CD who received a generic oral nutritional supplement (Fortisip) across 2 centers (RCH, Melbourne and RHSC, Edinburgh). This was compared with a prospective cohort (RHC, Glasgow) that used a specialized formula (Modulen IBD). The data collected included patient demographics, remission rates, biochemical markers, administration method, and anthropometrics. The estimated treatment cost was performed by comparing price per kcal between each formula.

RESULTS

One hundred seventy-one patients were included (106 Fortisip, 65 Modulen IBD, 70 female; median age 13.3 yrs). No difference was demonstrated in remission rate (Fortisip n = 67 of 106 [63%] vs Modulen IBD n = 41 of 64 [64%], P = .89), nonadherence rate (Fortisip n = 7 of 106 [7%] vs Modulen IBD 3 of 64 [5%], P = .57) or method of administration (NGT Fortisip use n = 16 of 106 [12%] vs Modulen IBD 14 of 65 [22%]; P = .31). There was no difference in reduction of biochemical disease markers between the groups (C-reactive protein , P = .13; erythrocyte sedimentation rate, P = .49; fecal calprotectin, P = .94). However, there was a cost-saving of around £500/patient/course if the generic oral nutritional supplement was used.

CONCLUSIONS

The generic oral nutritional supplement and specialized formulas both had similar clinical effectiveness in induction of remission in pediatric CD. However, there is considerable cost-saving when using a generic oral nutritional supplement.

A25 THE RISING GLOBAL INCIDENCE OF PEDIATRIC INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC REVIEW OF POPULATION-BASED STUDIES

Background

The incidence of inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is increasing internationally, particularly in developing nations where rates were historically low. Previous reports of the incidence and prevalence of pediatric-onset IBD have identified a paucity of population-based studies.

Aims

We reviewed the global trends in incidence of pediatric IBD using evidence from population-based studies.

Methods

(PROSPERO CRD42019125193) We systematically reviewed studies indexed in MEDLINE, EMBASE, Airiti Library, and SciELO from 01/2010-02/2020 to identify population-based studies reporting the incidence of pediatric-onset IBD, CD, and UC. Included studies combined childhood and adolescent-onset IBD (onset <21y). Changes in incidence since 2000 were plotted by continent, with data from 2000–09 provided by our previous systematic review1. To depict trends, multiple times points reported in single studies were connected on graphs. When incidence was reported as an aggregated estimate over a range of years, data was plotted using the midpoint of the interval.

Results

Of 8096 abstracts screened, 74 studies described the incidence of IBD, CD, or UC in 33 countries (Figure panel A). The incidence of pediatric-onset IBD is highest in Northern Europe and North America, and lowest in Southern Europe, Asia, and the Middle East. This geographical distribution is similar in UC, while incidence of pediatric-onset CD is highest in North America and Northern Europe, followed by Australia. Trends in incidence over time, stratified by continent, are reported in Figure, panel B. Significantly increasing incidence of IBD, CD, and/or UC was reported in China, Bahrain, Canada, New Zealand, Australia, Singapore, Saudi Arabia, and most European countries. Very Early Onset (VEO) IBD significantly increased in Canada, however Saudi Arabia reported decreasing incidence of VEO-CD but stable incidence of VEO-UC.

Conclusions

Conclusion: Incidence of pediatric-onset IBD are highest in Northern Europe and North American and are increasing globally. There remains a paucity of studies from many parts of the world on the incidence pediatric IBD. Further research is needed to understand the pathogenesis of the rising incidence of pediatric IBD, including work to understand the genetic, environmental, immunological and microbiome alterations leading to the increasing rates in children.

References: 1Benchimol, Fortinsky et al. Inflamm Bowel Dis 2011;17:423–39.

Funding Agencies

None

Associations between stopping prescriptions for opioids, length of opioid treatment, and overdose or suicide deaths in US veterans: observational evaluation

OBJECTIVE

To examine the associations between stopping treatment with opioids, length of treatment, and death from overdose or suicide in the Veterans Health Administration.

DESIGN

Observational evaluation.

SETTING

Veterans Health Administration.

PARTICIPANTS

1 394 102 patients in the Veterans Health Administration with an outpatient prescription for an opioid analgesic from fiscal year 2013 to the end of fiscal year 2014 (1 October 2012 to 30 September 2014).

MAIN OUTCOME MEASURES

A multivariable Cox non-proportional hazards regression model examined death from overdose or suicide, with the interaction of time varying opioid cessation by length of treatment (≤30, 31-90, 91-400, and >400 days) as the main covariates. Stopping treatment with opioids was measured as the time when a patient was estimated to have no prescription for opioids, up to the end of the next fiscal year (2014) or the patient's death.

RESULTS

2887 deaths from overdose or suicide were found. The incidence of stopping opioid treatment was 57.4% (n=799 668) overall, and based on length of opioid treatment was 32.0% (≤30 days), 8.7% (31-90 days), 22.7% (91-400 days), and 36.6% (>400 days). The interaction between stopping treatment with opioids and length of treatment was significant (P<0.001); stopping treatment was associated with an increased risk of death from overdose or suicide regardless of the length of treatment, with the risk increasing the longer patients were treated. Hazard ratios for patients who stopped opioid treatment (with reference values for all other covariates) were 1.67 (≤30 days), 2.80 (31-90 days), 3.95 (91-400 days), and 6.77 (>400 days). Descriptive life table data suggested that death rates for overdose or suicide increased immediately after starting or stopping treatment with opioids, with the incidence decreasing over about three to 12 months.

CONCLUSIONS

Patients were at greater risk of death from overdose or suicide after stopping opioid treatment, with an increase in the risk the longer patients had been treated before stopping. Descriptive data suggested that starting treatment with opioids was also a risk period. Strategies to mitigate the risk in these periods are not currently a focus of guidelines for long term use of opioids. The associations observed cannot be assumed to be causal; the context in which opioid prescriptions were started and stopped might contribute to risk and was not investigated. Safer prescribing of opioids should take a broader view on patient safety and mitigate the risk from the patient's perspective. Factors to address are those that place patients at risk for overdose or suicide after beginning and stopping opioid treatment, especially in the first three months.

A Qualitative Study about Creating Smoke-free Home Rules in American Indian and Alaska Native Households

Smoke-free homes can reduce exposure to secondhand smoke (SHS) and support smoking cessation. The current study seeks to understand perspectives, including barriers and facilitators, on smoke-free homes among five American Indian/Alaska Native (AI/AN) communities. Guided by a national work group of tribal partners, ten focus groups were conducted with AI/AN adult smokers and nonsmokers (n = 95) in Alaska, California, Michigan and Oklahoma, stratified by smoking status. The majority of participants lived in single unit detached homes (70.5%). Most of the nonsmokers had a smoke-free home rule (92.9%) and a majority of smokers did as well (64.7%). The most common reasons for smoke-free home rules were protecting children and grandchildren, including children with health problems. Challenges to a smoke-free home included weather and visitors who smoked, along with the inconvenience of going outside, the habit of smoking inside, the need to watch a young child, safety concerns, and smokers who break the rules. Respecting rules and respecting elders emerged as important themes. Traditional use of tobacco in the home was viewed as quite distinct from recreational or everyday use. Over half (58.2%) reported never using tobacco for ceremonial, prayer or traditional reasons in their homes. Given unique considerations for the adoption of smoke-free homes in AI/AN communities, particularly regarding the use of sacred tobacco for traditional, ceremonial, or medicinal purposes, it is important to learn which barriers and facilitators are similar to the general population and which may be unique to tribal communities in the U.S.

Adaptation of a brief smoke-free homes intervention for American Indian and Alaska Native families

BACKGROUND

The goal of adaptation is to maintain the effectiveness of the original intervention by preserving the core elements that account for its success while delivering an intervention that is tailored to the new community and/or cultural context. The current study describes the process of adapting an evidence-based smoke-free homes (SFH) intervention for use in American Indian/Alaska Native (AI/AN) households.

METHODS

We followed a systematic adaptation process. We first assessed the community through focus groups coordinated in collaboration with tribal partners. Because our team included the original developers of the intervention, the steps of understanding the intervention, selecting the intervention and consulting with experts were simplified. Additional steps included consulting with stakeholders through a national work group and collaboratively deciding what needed adaptation.

RESULTS

A number of key themes pertinent to the adaptation of the SFH intervention were identified in the focus groups. These included the gravity of messaging about commercial tobacco use; respect, familialism, and intergenerationalism; imagery, including significant symbolism, colors, and representative role models; whether and how to address traditional tobacco; and, barriers to a SFH not adequately addressed in the original materials.

CONCLUSIONS

Adaptation of an intervention to create smoke-free homes in AI/AN families necessitated both surface structure changes such as appearance of role models and deep structure changes that addressed core values, and beliefs and traditions.

A gene-family analysis of 61 genetic variants in the nicotinic acetylcholine receptor genes for insulin resistance and type 2 diabetes in American Indians

Cigarette smoking is a risk factor for type 2 diabetes. Genetic variants in the nicotinic acetylcholine receptor (nAChR) genes have been associated with smoking phenotypes and are likely to influence diabetes. Although each single variant may have only a minor effect, the joint contribution of multiple single nucleotide polymorphisms (SNPs) to the occurrence of disease may be larger. In this study, we conducted a gene-family analysis to investigate the joint impact of 61 tag SNPs in 7 nAChRs genes on insulin resistance and type 2 diabetes in 3,665 American Indians recruited by the Strong Heart Family Study. Results show that although multiple SNPs showed marginal individual association with insulin resistance and type 2 diabetes, only a few can pass adjustment for multiple testing. However, a gene-family analysis considering the joint impact of all 61 SNPs reveals significant association of the nAChR gene family with both insulin resistance and type 2 diabetes (both P < 0.0001), suggesting that genetic variants in the nAChR genes jointly contribute to insulin resistance and type 2 diabetes among American Indians. The effects of these genetic variants on insulin resistance and diabetes are independent of cigarette smoking per se.

Risk of future trauma based on alcohol screening scores: a two-year prospective cohort study among US veterans

BACKGROUND

Severe alcohol misuse as measured by the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) is associated with increased risk of future fractures and trauma-related hospitalizations. This study examined the association between AUDIT-C scores and two-year risk of any type of trauma among US Veterans Health Administration (VHA) patients and assessed whether risk varied by age or gender.

METHODS

Outpatients (215, 924 male and 9168 female) who returned mailed AUDIT-C questionnaires were followed for 24 months in the medical record for any International Statistical Classification of Diseases and Related Health Problems (ICD-9) code related to trauma. The two-year prevalence of trauma was examined as a function of AUDIT-C scores, with low-level drinking (AUDIT-C 1-4) as the reference group. Men and women were examined separately, and age-stratified analyses were performed.

RESULTS

Having an AUDIT-C score of 9-12 (indicating severe alcohol misuse) was associated with increased risk for trauma. Mean (SD) ages for men and women were 68.2 (11.5) and 57.2 (15.8), respectively. Age-stratified analyses showed that, for men≤50 years, those with AUDIT-C scores≥9 had an increased risk for trauma compared with those with AUDIT-C scores in the 1-4 range (adjusted prevalence, 25.7% versus 20.8%, respectively; OR=1.24; 95% confidence interval [CI], 1.03-1.50). For men≥65 years with average comorbidity and education, those with AUDIT-C scores of 5-8 (adjusted prevalence, 7.9% versus 7.4%; OR=1.16; 95% CI, 1.02-1.31) and 9-12 (adjusted prevalence 11.1% versus 7.4%; OR=1.68; 95% CI, 1.30-2.17) were at significantly increased risk for trauma compared with men≥65 years in the reference group. Higher AUDIT-C scores were not associated with increased risk of trauma among women.

CONCLUSIONS

Men with severe alcohol misuse (AUDIT-C 9-12) demonstrate an increased risk of trauma. Men≥65 showed an increased risk for trauma at all levels of alcohol misuse (AUDIT-C 5-8 and 9-12). These findings may be used as part of an evidence-based brief intervention for alcohol use disorders. More research is needed to understand the relationship between AUDIT-C scores and risk of trauma in women.

Associations between AUDIT-C and mortality vary by age and sex

We sought to determine the sex- and age-specific risk of mortality associated with scores on the 3-item Alcohol Use Disorder Identification Test-Consumption (AUDIT-C) questionnaire using data from a national sample of Veterans Health Administration (VHA) patients. Men (N = 215,924) and women (N = 9168) who completed the AUDIT-C in a patient survey were followed for 24 months. AUDIT-C categories (0, 1-4, 5-8, 9-12) were evaluated as predictors of mortality in logistic regression models, adjusted for age, race, education, marital status, smoking, depression, and comorbidities. For women, AUDIT-C scores of 9-12 were associated with a significantly increased risk of death compared to the AUDIT-C 1-4 group (odds ratio [OR] 7.09; 95% confidence interval [CI] = 2.67, 18.82). For men overall, AUDIT-C scores of 5-8 and 9-12 were associated with increased risk of death compared to the AUDIT-C 1-4 group (OR 1.13, 95% CI = 1.05, 1.21, and OR 1.63, 95% CI = 1.45, 1.84, respectively) but these associations varied by age. These results provide sex- and age-tailored risk information that clinicians can use in evidence-based conversations with patients about the health-related risks of their alcohol consumption. This study adds to the growing literature establishing the AUDIT-C as a scaled marker of alcohol-related risk or "vital sign" that might facilitate the detection and management of alcohol-related risks and problems.

Management of Psychosexual Problems in Primary Care

Sexual health can be described as enjoying and fulfilling sexual desires without causing harm, physical or psychological, to oneself or others. Psychosexual problems affect about 40% of the population and sexual functioning is an important part of a patient's health and well-being. Patients often present late due to embarrassment and commonly with an alternative problem. Learning to recognize and act upon both verbal and non-verbal clues, with empathy, is essential in their management. This article aims to give an overview of common psychosexual problems, specific circumstances where they present more frequently and management options.

Two Novel Mutations Causing Familial Benign Hypocalciuric Hypercalcaemia in Three Scottish Families

Background and Aims

Familial benign hypocalciuric hypercalcaemia (FBHH) is a benign autosomal dominantly inherited condition which results in elevated serum calcium and low urinary calcium. This condition is of clinical interest because it can be mistakenly diagnosed as primary hyperparathyroidism (PHP). In most cases FBHH can be shown to be due to a mutation in the calcium sensing receptor (CASR) gene and we aimed to find the causative mutation in three Scottish kindreds with FBHH.

Methods

We used a combination of denaturing gradient gel electrophoresis and direct DNA sequencing to detect mutations in the CASR gene.

Results

We detected a mutation in the CASR gene in each of the three kindreds. Two different mutations were detected (the same one was present in two kindreds). Neither mutation has been reported previously. All hypercalcaemic individuals from each kindred had the appropriate mutation while all normocalcaemic individuals did not.

Conclusion

In the vast majority of kindreds with FBHH which have been reported previously, the CASR mutation responsible is private to that kindred. In three Scottish kindreds we have identified two new mutations.

Design of a phase 0 microdosing trial for correlation of platinum-induced DNA damage to chemotherapy outcomes

2543

Background: DNA damage is the critical step in cancer cell response to platinum (Pt) chemotherapy. We hypothesize that low levels of Pt-induced DNA damage are predictive of chemoresistance. Accelerator mass spectrometry (AMS), an ultrasensitive method for measuring radiocarbon, can detect [14C]carboplatin bound to the DNA of cancer cells from cell culture, mice bearing tumor xenografts and patients receiving subtoxic microdoses of compound. Methods: Cancer cells and mice bearing tumor xenografts were treated with one microdose (1/100th of the therapeutic dose) or one therapeutic dose of [14C]carboplatin. Relevant parameters such as drug influx/efflux, intracellular drug inactivation, DNA damage and repair, were measured and correlated with response to chemotherapy. A Phase 0 microdosing trial has been designed to study patients with non-small cell lung or bladder transitional cell cancers who are planning to receive Pt-based chemotherapy. One microdose of [14C]carboplatin is administered to these patients 4 hours before biopsy. Pt-induced DNA damage and repair in tumor biopsy specimens and other relevant parameters will be measured and correlated with the response and toxicity of chemotherapy. Results: Preclinical studies showed that AMS can detect Pt-DNA damage when cancer cells and mice with tumor xenografts are exposed to one microdose of [14C]carboplatin. The levels of microdose-induced DNA damage are directly proportional to the damage caused by a therapeutic drug dose (p<0.001); and these levels of DNA damage correlate with chemoresistance as measured by MTT assay. Measuring drug uptake/efflux and intracellular inactivation allows insights into resistance mechanisms. These data support the conclusion that the levels of DNA damage induced by microdosing can potentially predict chemoresistance in patients. Consequently, a Phase 0 microdosing trial is in progress. Conclusions: These results support a phase 0 microdosing trial employing AMS to identify chemoresistance and determine the underlying chemoresistant mechanisms for personalized therapy before patients receive cytotoxic chemotherapy.

[Table: see text]

Assisting medical students to conduct empathic conversations with patients from a sexual medicine clinic

OBJECTIVE

To describe an exercise, the structure and content of which assists medical students to conduct potentially embarrassing conversations concerning sexual health which require expression of empathy, to integrate previous learning, to identify their further learning needs, and to develop and test strategies to meet these needs.

METHOD

Students' role play, sequentially, speakers (patients) and listeners (clinical students) in a "carousel," in which all students are engaged at all times in a sequence of pairings which change at rapid intervals. Half way through the exercise, students reflect on the experience, identify difficulties and successes, and develop and share strategies for experimental use in the second half of the exercise.

RESULTS

Qualitative comments from the written student evaluations are reported.

CONCLUSIONS

The exercise provides a formative student centred approach to the integration and further development of previously learnt knowledge and skills of value for promoting sexual health education. It is useful for educators interested in promoting more open and informed learning about sexual health.

Assisting medical students to conduct empathic conversations with patients from a sexual medicine clinic

OBJECTIVE

To describe an exercise, the structure and content of which assists medical students to conduct potentially embarrassing conversations concerning sexual health which require expression of empathy, to integrate previous learning, to identify their further learning needs, and to develop and test strategies to meet these needs.

METHOD

Students' role play, sequentially, speakers (patients) and listeners (clinical students) in a "carousel," in which all students are engaged at all times in a sequence of pairings which change at rapid intervals. Half way through the exercise, students reflect on the experience, identify difficulties and successes, and develop and share strategies for experimental use in the second half of the exercise.

RESULTS

Qualitative comments from the written student evaluations are reported.

CONCLUSIONS

The exercise provides a formative student centred approach to the integration and further development of previously learnt knowledge and skills of value for promoting sexual health education. It is useful for educators interested in promoting more open and informed learning about sexual health.

Prevalence and numbers of Salmonella and Campylobacter spp. on raw, whole chickens in relation to sampling methods

Salmonella and Campylobacter continue to be major foodborne pathogens and raw poultry is considered to be an important source of these bacteria. In this study, the prevalence and numbers of Salmonella and Campylobacter spp. in relation to isolation/sampling methods were determined in 241 whole raw chickens purchased from retail outlets in England during the winters of 1998/1999 (101 chickens) and 1999/2000 (140 chickens). The packaging of the 140 chickens was also examined for the presence of the above pathogens. The prevalence and numbers of enterococci were examined in 21 of the 101 chickens. In total, Salmonella and Campylobacter spp. were present in 25% and 83% of the chickens, respectively. Salmonella were isolated from a sample representing both the inside and outside of the packaging in 19% of the chickens, while the corresponding figure for Campylobacter spp. was 56%. Both of these pathogens were isolated from the outside of the packaging in 6% of the chickens. Salmonella was more frequently isolated from samples containing chicken skin in comparison with those containing carcass-rinse fluid only. Two chickens (0.8%) were positive for Salmonella by direct enumeration methods with contamination levels of log10 3.8 and 4.5 colony forming units (cfu) per carcass, respectively. The most prevalent serotypes were S. Hadar, S. Enteritidis and S. Indiana and two different serotypes were identified in 5/20 salmonella-positive chickens. Resistance to at least one antibiotic was found in 70% of the strains, 46% were multiresistant (resistant to > or = four drugs) and 52% showed a lowered susceptibility to ciprofloxacin. The likelihood of isolating Campylobacter spp. from neck-skin, carcass-rinse or carcass-rinse plus whole skin samples was similar, Campylobacter spp. were found in higher levels in carcass-rinse or carcass-rinse plus whole skin samples than in neck-skin. The log10 cfu of Campylobacter spp. were 2.70-4.99 in 18% of the chickens and 5.00-6.99 in 20%. Campylobacter isolates (425) comprised Campylobacter jejuni (98%) and C. coli (2%) and 98 different sero/phagetypes of these two species were identified. Resistance to at least one antibiotic was found in 73% of the strains and 13% were multiresistant. Thirteen percent of the strains showed lowered susceptibility to ciprofloxacin, while 4.9% were resistant to erythromycin. Vancomycin-resistant enterococci (VRE), able to grow on agar containing 15 mg l(-1) vancomycin (VRE15), were present in 19 chickens. The log10 cfu of VRE15 was 2.90-3.99 in 10 chickens and between 4.00 and 4.99 in two chickens. The data presented here contribute to risk assessment and highlight the need to continue to emphasise the safe handling of raw retail poultry.

Do parents value drowning prevention information at discharge from the emergency department?

STUDY OBJECTIVE

We determined parent recall and perceived usefulness of drowning prevention messages included in routine computer-generated discharge instructions.

METHODS

All pediatric emergency department patients' computerized discharge instructions included 3 prevention messages: wear a life vest, swim in safe areas, and do not drink alcohol while swimming or boating. Parents were telephoned 1 to 2 weeks after the visit and asked to recall the prevention messages and rate the usefulness of the instructions. Responses were linked with patient characteristics and ED visit variables (day and time of visit, duration of ED visit, severity of condition, diagnostic category, number of tests, and treatments).

RESULTS

Of 914 parents who were contacted, 795 were eligible. Of those, 619 (78%) completed the interview. Fifty percent of parents recalled receiving drowning prevention information; of these, 41% recalled unaided the life vest messages and 35% of 155 parents who did not own a life vest stated they would subsequently consider buying their child a life vest. Most (88%) rated the prevention information useful or very useful. No patient or visit variables were associated with usefulness ratings.

CONCLUSION

Written injury prevention messages with discharge instructions were well received by parents of children in a pediatric ED. The ED may be a setting where families could receive injury prevention education.

Prokaryote multidrug efflux proteins of the major facilitator superfamily: amplified expression, purification and characterisation

In bacterial genomes 3-12% of open reading frames are predicted to encode membrane transport proteins. These proteins can be vital for antibiotic efflux, protein/ toxin secretion, cell nutrition, environmental sensing, ATP synthesis, and other functions. Some, such as the multidrug efflux proteins, are potential targets for the development of new antibacterials and also for applications in biotechnology. In general membrane transport proteins are poorly understood, because of the technical difficulties involved in isolating sufficient protein for elucidation of their structure-activity relationships. We describe a general strategy for the amplified expression, purification and characterisation of prokaryotic multidrug efflux proteins of the 'Major facilitator superfamily' of transport proteins, using the Bacillus subtilis multidrug resistance protein, 'Bmr', as example.

[Spending and financing in health care: situation and trends]

Being knowledgeable about national health expenditures and sources of financing is essential for decision-making. This awareness also makes it possible to evaluate the equity of allocation and the efficiency of utilization of these resources. Changes in financing have been a substantial component of health sector reform in the Americas. The goal has shifted from merely one of financial sustainability to simultaneously seeking equitable access to quality services. In this article the Pan American Health Organization (PAHO) presents a proposal for analyzing and designing a policy on health financing. The aim of the policy is to identify the mix of financing mechanisms most likely to simultaneously produce financial sustainability, equity, access, and efficiency. The PAHO proposal combines traditional mechanisms for generating resources (public funds from taxes, as well as private health insurance, national health insurance, and user fees) with complementary subsidy mechanisms for vulnerable groups. Health financing strategies ought to explicitly consider the financing both of care for individuals and of health interventions for the general public good, for which public financing is the most equitable and efficient approach.

Clearance of tissue plasminogen activator (TPA) and TPA/plasminogen activator inhibitor type 1 (PAI-1) complex: relationship to elevated TPA antigen in patients with high PAI-1 activity levels

BACKGROUND

To evaluate the effect of plasminogen activator inhibitor type 1 (PAI-1) levels on the clearance of total tissue plasminogen activator (TPA) antigen, we studied the clearance of active TPA and TPA/PAI-1 complex in subjects with low (181+/-109 pmol/L; n=7) and high (1166+/-322 pmol/L; n=4) baseline active PAI-1.

METHODS AND RESULTS

A 5-microg/kg bolus of TPA was infused over a 15-second period followed by measurement of TPA activity, TPA antigen, TPA/PAI-1, TPA/C1 inhibitor, PAI-1 activity, and PAI-1 antigen over a 4-hour period. alpha-Phase clearance of total TPA antigen was faster in subjects with low PAI-1 (t(1/2) of 3.5+/-0.7 minutes) versus high PAI-1 (t(1/2) of 5.3+/-0.9 minutes) (P=.006). Clearance of all factors was best fit by a two-compartment pharmacokinetic model based on a computer-simulated human circulatory system. The average hepatic clearance fraction in the two-compartment model was greater for active TPA (89+/-10%, t(1/2) of 2.4+/-0.3 minutes) than for TPA/PAI-1 complex (48+/-17%, t(1/2) of 5.0+/-1.8 minutes) (P=.0006).

CONCLUSIONS

Plasma clearance of active TPA was faster than clearance of TPA/PAI-1 complex. High levels of active PAI-1 converted more TPA into TPA/PAI-1 complex, effectively slowing the clearance of total TPA antigen and explaining in part why high levels of PAI-1 activity are associated with increases in total TPA antigen.

Differential effects of G-protein activators on 5-hydroxytryptamine and platelet-derived growth factor release from streptolysin-O-permeabilized human platelets

In this paper we have used streptolysin O (SLO)-permeabilized human platelets to examine the G-protein(s) that control Ca2+-independent secretion from alpha and dense-core granules. As shown for electropermeabilized platelets, Ca2+ alone stimulated a concentration-dependent increase in 5-hydroxytryptamine (5-HT) (dense-core-granule marker) and platelet-derived growth factor (PDGF) (alpha-granule marker) release from the SLO-permeabilized cells. The EC50 values of Ca2+-dependent 5-HT and PDGF release were 5 microM and 10 microM respectively. Guanosine 5'-[gamma-thio]triphosphate (GTP[S]) (100 microM) stimulated Ca2+-independent release from both alpha and dense-core granules. In contrast, AlF4- had no effect on Ca2+-independent release from either alpha or dense-core granules. Neither GTP[S] nor AlF4- appeared to have a significant effect on Ca2+-dependent release from alpha and dense-core granules. GTP[S] can activate both heterotrimeric and low-molecular-mass G-proteins, whereas AlF4- activates only heterotrimeric G-proteins. Our results, therefore suggest that secretion in the human platelet is regulated by a small G-protein. Both GTP[S]- and Ca2+-dependent secretion were effected by extending the time between permeabilization with SLO and stimulation of secretion. GTP[S]-stimulated secretion from alpha and dense-core granules decreased rapidly after permeabilization. In contrast, Ca2+-dependent 5-HT and PDGF release ran down at a much lower rate. These observations indicate that GTP[S] and Ca2+ act through parallel pathways to stimulate secretion from SLO-permeabilized platelets.

Prevalence of antithrombin deficiency in healthy blood donors: a cross-sectional study

The prevalence of antithrombin (AT) deficiency in the general population has been variously estimated to be between 0.05 and 5 per 1,000 in the population; 2,491 blood donors were screened in an attempt to clarify this issue using plasma samples taken from the blood donor units. From this initial population, 122 individuals were identified as having plasma AT levels lower than 2 standard deviations below the normal mean. Twenty-two samples had evidence that thrombin had been generated during blood collection and the remaining cohort of 100 blood donors were asked to return but only 59 complied. The data obtained from these 59 were compared with that from 51 age- and sex-matched control blood donors. Both groups of subjects were assessed for previous evidence, or family history, of thrombotic events, as well as exposure to risk factors associated with the development of deep vein thrombosis (DVT). All had venous blood samples taken from which the supernatant plasma was immediately removed and quick frozen for later assaying. Only 6 of the 59 subjects with initial low AT levels had repeat AT-Xa levels below 0.80 units/ml (normal range 0.94 +/- 0.14). Upon repeating the AT-Xa determinations on new samples from these six individuals, only three were found again to be low. One was found to have a type 3 AT deficiency (an Arg47Cys substitution). The other two with a low AT level had mean functional AT-Xa levels of 0.61 and 0.71 units/ml, respectively, with correspondingly low AT:Ag levels consistent with a type 1 AT deficiency. Two of these three subjects has been in high risk situations without evidence of having developed DVT and none had evidence of venous reflux on Doppler venography. In addition, none had personal or family histories of previous thrombotic events. These present data indicate that the prevalence of AT deficiency in our blood donor population is 2 per 1,000 (95% confidence intervals: 0.7-6/1,000).

Estimating past exposure to indoor radon from household glass

CR-39 plastic was attached to household glass objects to learn whether residual radioactivity from radon decay products could be measured and correlated with cumulative radon exposures over defined time periods. Such an approach could be used to increase the completeness of exposure data collected in epidemiologic studies of residential radon. Inability to estimate radon concentrations for all residences adversely effects statistical power and thus the ability to detect an effect of radon exposure on lung cancer risk. A feasibility study was performed to determine if affixing CR-39 surface monitors to selected glass, ceramic, or enameled objects provided comparable estimates of past residential radon exposure to those obtained from year-long ambient alpha track-etch measurements. The CR-39 measurements of alpha activity in the surface of selected objects correlated with ambient radon measurements (R2 = 0.48) provided that reliable information was obtained on the history and age of the objects. This technique has now been incorporated into an epidemiologic study of radon and lung cancer to more fully estimate past exposure to indoor radon.

An antithrombin III assay based on factor Xa inhibition provides a more reliable test to identify congenital antithrombin III deficiency than an assay based on thrombin inhibition

OBJECTIVES

To determine whether functional antithrombin III (AT-III) levels measured by a factor Xa inhibition (AT-III-Xa) assay identifies AT-III deficient individuals more reliably than functional AT-III levels measured by a thrombin inhibition (AT-III-IIa) assay.

STUDY DESIGN

Cross-sectional study.

PATIENT POPULATION

Sixty-seven members of a large family with type 2 AT-III deficiency.

INTERVENTION

DNA analysis was used as the reference diagnostic standard for AT-III status and subjects were classified as AT-III deficient or non deficient according to these results. Functional AT-III levels were measured in all subjects using: 1) a chromogenic substrate for thrombin and added human thrombin (AT-III-IIa), and 2) a chromogenic substrate for factor Xa and added bovine factor Xa (AT-III-Xa). Functional heparin cofactor II (HC-II) levels were measured using a commercially available kit. The proportions of 125I-alpha-thrombin complexed to AT-III and HC-II were measured by polyacrylamide gel electrophoresis and autoradiography.

RESULTS

Thirty-one (46%) individuals were classified as AT-III deficient and 36 (54%) as AT-III non deficient. AT-III-Xa assay measured a significantly lower mean AT-III value and a narrower range for individuals classified as AT-III deficient than the AT-III-IIa assay. Using the AT-III-IIa assay, six subjects had borderline AT-III levels compared to none with the AT-III-Xa assay.(ABSTRACT TRUNCATED AT 250 WORDS)

What, me worry? A survey of adolescents' concerns

Adolescence is generally regarded as a time of transition demanding considerable adaptation. Failing to successfully negotiate the developmental hurdles associated with this period can have serious physical and psychosocial consequences (e.g., teenage pregnancy, suicide, disruption of social relationships, poor school performance). Efforts to identify problems that adolescents typically experience have been useful in facilitating a better understanding of this developmental phase. However, the perceived concerns or worries of adolescents themselves have been neglected as an additional source of useful information. This study assessed the worries of 622 adolescents between the ages of 12 and 20 years on an 80-item self-report measure, the "Things That Worry Me" scale. Findings indicated consistent concerns related to terrorism, adolescents' self-esteem, parents' physical and mental health, and adolescents' dating and sexual relationships. Gender- and race-specific differences are discussed and implications for future research and clinical applications are offered.

Pharmacokinetics of lignocaine in children after infiltration for cleft palate surgery

We have studied the pharmacokinetics of lignocaine in children after local infiltration for cleft palate surgery. After induction of anaesthesia, lignocaine 2.5 mg kg-1 with adrenaline 1:200,000 was injected into the palate. Blood samples were collected before and at 2, 5, 10, 15, 20, 30, 60 and 120 min after infiltration. Plasma concentrations of lignocaine were measured by a gas-liquid chromatographic technique. There were no signs of systemic toxicity on routine monitoring of the patients and the peak plasma concentrations were less than the accepted toxic values. Mean half-life was 72.9 (SEM 9.9) min, similar to that found previously in adults and children. However differences in mean clearance (24.6 (2.04) ml kg-1 min-1) and volume of distribution (0.80 (0.07) litre kg-1) were found between this and previous studies.

Measurement of markers of activated coagulation in antithrombin III deficient subjects

Functional antithrombin III levels were measured by factor Xa inhibition in 63 members of a large family with type 2 antithrombin III deficiency and individuals were classified as antithrombin III deficient or non-deficient according to the results. F1 + 2 and TAT complexes were measured using an ELISA and FPA levels were measured by radioimmunoassay. Thirty subjects (48%) were classified as antithrombin III deficient and 33 (52%) as antithrombin III non-deficient. The mean level of F1 + 2 was significantly higher in the deficient adults (0.87 +/- 0.26) compared to both the non-deficient adults (0.70 +/- 0.21) (p = 0.03) and the deficient adults receiving warfarin (0.16 +/- 0.01) (p less than 0.001). The differences in the mean values of TAT complexes and FPA between deficient and non-deficient individuals were not statistically significant. These findings suggest that untreated antithrombin III deficient subjects generate more thrombin than their non-deficient family members and that warfarin inhibits this thrombin formation. In this cross-sectional study, it is not possible to correlate the levels of the surrogate makers with future clinical outcome.

Thrombosis in antithrombin-III-deficient persons. Report of a large kindred and literature review

PURPOSE

To estimate the prevalence of objectively proven thrombotic complications in antithrombin-III-deficient persons.

STUDY DESIGN

Cross-sectional study and a critical review of the literature.

DATA SOURCES AND EXTRACTION

The prevalence of thrombosis in antithrombin III-deficient and -nondeficient family members of a large kindred was estimated by history, review of diagnostic tests, and examination for venous reflux by Doppler ultrasonography, as an indicator of previous venous thrombosis. A MEDLINE search and literature review of the published English- and French-language literature from 1966 to 1990 that described antithrombin-III-deficient families was done, and the following information was obtained: the prevalence of thrombosis in deficient and nondeficient family members, the presence or absence of risk factors for thrombosis (surgery, pregnancy, the postpartum state, use of oral contraceptives, immobilization, metastatic cancer, major trauma) at the time of the thrombotic event, and age of onset of the first episode of thrombosis. The validity of the studies was assessed according to predetermined criteria.

RESULTS

Sixty-seven research subjects were evaluated. Six of 31 (19.4%) antithrombin-III-deficient subjects compared with none of 36 (0%) nondeficient subjects had had one or more thrombotic events. The initial episode in five of six subjects had occurred in association with risk factors for thrombosis. The literature search indicated that the pooled prevalence of symptomatic venous thrombosis among the deficient subjects was 51%, but objective testing was done in only 17% of these subjects at the time of presentation.

CONCLUSION

Based on the data from this antithrombin-III-deficient kindred, lifelong anticoagulant prophylaxis does not appear to be warranted in asymptomatic carriers, and prophylaxis could be limited to periods of high risk for thrombosis.