Background: The increased availability of genetic tests for common, complex diseases, such as Alzheimer's disease (AD), raises questions about what people are willing to pay for these services. Methods: We studied willingness-to-pay for genetic testing in a study of AD risk assessment that included APOE genotype disclosure among 276 first-degree relatives of persons with AD. Results: Seventy-one percent reported that they would ask for such testing from their doctor if it were covered by health insurance, and 60% would ask for it even if it required self-pay. Forty-one percent were willing to pay more than $100 for testing, and more than half would have been willing to pay for the test out of pocket. Participants who learned that they were APOE ɛ4 positive and those who had higher education were less likely to want testing if covered by insurance, possibly to avoid discrimination. Conclusion: This is the first report to examine willingness to pay for susceptibility genetic testing in a sample of participants who had actually undergone such testing. These findings reveal that some participants find valuable personal utility in genetic risk information even when such information does not have proven clinical utility.
Although GABAergic interneurons are the main source of synaptic inhibition in the cortex, activation of GABAA receptors has been shown to depolarize specific neuronal compartments, resulting in excitation. By using a noninvasive approach to monitor the effect of individual interneurons on the pyramidal cell population, we found that rat hippocampal interneurons hyperpolarized pyramidal cells irrespective of the location of their synapses along the somato-dendritic axis.
The intake of dietary fatty acids is highly correlated with the risk of various cancers. Linoleic acid (LA) is the most abundant polyunsaturated fat in the western diet, but the mechanism(s) by fatty acids such as LA modulate cancer cells is unclear. In this study, we examined the role of LA in various steps in gastric cancer progression.
The difference in gene expression between LA-treated and untreated OCUM-2MD3 gastric carcinoma cells was examined by mRNA differential display. The involvement of candidate genes was examined by oligo- and plasmid-mediated RNA interference. Biological functions of several of these genes were examined using in vitro assays for invasion, angiogenesis, apoptosis, cell viability, and matrix digestion. Angiogenesis in vivo was measured by CD-31 immunohistochemistry and microvessel density scoring.
LA enhanced the plasminogen activator inhibitor 1 (PAI-1) mRNA and protein expression, which are controlled by PAI-1 mRNA-binding protein. LA-stimulated invasion depended on PAI-1. LA also enhanced angiogenesis by suppression of angiostatin, also through PAI-1. LA did not alter cell growth in culture, but increased dietary LA-enhanced tumour growth in an animal model.
Our findings suggest that dietary LA impacts multiple steps in cancer invasion and angiogenesis, and that reducing LA in the diet may help slow cancer progression.
gastric carcinoma; linoleic acid; plasminogen activator inhibitor 1; angiostatin; invasion
Susceptibility testing for common, complex adult-onset diseases is projected to become more commonplace as the rapid pace of genomic discoveries continues, and evidence regarding the potential benefits and harms of such testing is needed to inform medical practice and health policy. Apolipoprotein E (APOE) testing for risk of Alzheimer’s disease (AD) provides a paradigm in which to examine the process and impact of disclosing genetic susceptibility for a prevalent, severe and incurable neurological condition. This review summarizes findings from a series of multi-site randomized clinical trials examining psychological and behavioral responses to various methods of genetic risk assessment for AD using APOE disclosure. We discuss challenges involved in disease risk estimation and communication and the extent to which participants comprehend and perceive utility in their genetic risk information. Findings on the psychological impact of test results are presented (e.g., distress), along with data on participants’ health behavior and insurance purchasing responses (e.g., long term care). Finally, we report comparisons of the safety and efficacy of intensive genetic counseling approaches to briefer models that emphasize streamlined processes and educational materials. The implications of these findings for the emerging field of personal genomics are discussed, with directions identified for future research.
Individual cancers harbor a set of genetic aberrations that can be informative for identifying rational therapies currently available or in clinical trials. We implemented a pilot study to explore the practical challenges of applying high-throughput sequencing in clinical oncology. We enrolled patients with advanced or refractory cancer who were eligible for clinical trials. For each patient, we performed whole-genome sequencing of the tumor, targeted whole-exome sequencing of tumor and normal DNA, and transcriptome sequencing (RNA-Seq) of the tumor to identify potentially informative mutations in a clinically relevant time frame of 3 to 4 weeks. With this approach, we detected several classes of cancer mutations including structural rearrangements, copy number alterations, point mutations, and gene expression alterations. A multidisciplinary Sequencing Tumor Board (STB) deliberated on the clinical interpretation of the sequencing results obtained. We tested our sequencing strategy on human prostate cancer xenografts. Next, we enrolled two patients into the clinical protocol and were able to review the results at our STB within 24 days of biopsy. The first patient had metastatic colorectal cancer in which we identified somatic point mutations in NRAS, TP53, AURKA, FAS, and MYH11, plus amplification and overexpression of cyclin-dependent kinase 8 (CDK8). The second patient had malignant melanoma, in which we identified a somatic point mutation in HRAS and a structural rearrangement affecting CDKN2C. The STB identified the CDK8 amplification and Ras mutation as providing a rationale for clinical trials with CDK inhibitors or MEK (mitogenactivated or extracellular signal–regulated protein kinase kinase) and PI3K (phosphatidylinositol 3-kinase) inhibitors, respectively. Integrative high-throughput sequencing of patients with advanced cancer generates a comprehensive, individual mutational landscape to facilitate biomarker-driven clinical trials in oncology.
We reported that Notch-1, a potent breast oncogene, is activated in response to trastuzumab and contributes to trastuzumab resistance in vitro. We sought to determine the preclinical benefit of combining a Notch inhibitor (γ-secretase inhibitor (GSI)) and trastuzumab in both trastuzumab-sensitive and trastuzumab-resistant, ErbB-2-positive, BT474 breast tumours in vivo. We also studied if the combination therapy of lapatinib plus GSI can induce tumour regression of ErbB-2-positive breast cancer.
We generated orthotopic breast tumour xenografts from trastuzumab- or lapatinib-sensitive and trastuzumab-resistant BT474 cells. We investigated the antitumour activities of two distinct GSIs, LY 411 575 and MRK-003, in vivo.
Our findings showed that combining trastuzumab plus a GSI completely prevented (MRK-003 GSI) or significantly reduced (LY 411 575 GSI) breast tumour recurrence post-trastuzumab treatment in sensitive tumours. Moreover, combining lapatinib plus MRK-003 GSI showed significant reduction of tumour growth. Furthermore, a GSI partially reversed trastuzumab resistance in resistant tumours.
Our data suggest that a combined inhibition of Notch and ErbB-2 signalling pathways could decrease recurrence rates for ErbB-2-positive breast tumours and may be beneficial in the treatment of recurrent trastuzumab-resistant disease.
ErbB-2; trastuzumab; Notch-1; GSI; recurrence; resistance
It is commonly accepted that inefficient recruitment and inadequate retention continue to threaten the completion of clinical trials intended to reduce the public health burden of neurological disease. This article will discuss the scientific, economic, and ethical implications of failure to recruit and retain adequate samples in clinical trials, including the consequences of failing to recruit adequately diverse samples. We will also discuss the more common challenges and barriers to efficient and effective recruitment and retention, and the impact these have on successful clinical trial planning. We will explain the newly established efforts within National Institute of Neurological Disorders and Stroke (NINDS) to monitor recruitment and retention with well-defined metrics and implementation of grant awards that include feasibility milestones for continued funding. Finally, we will describe our efforts to address some of the common challenges to recruitment and retention through assistance to investigators and coordinators with evidence-based support, tools, and resources for planning and strategizing recruitment and retention as well as a trans-NIH effort to improve awareness of clinical research in the general public.
Genetic susceptibility testing for common diseases is expanding, but little is known about race group differences in test perceptions. The purpose of this study was to examine differences between African Americans and Whites in knowledge, attitudes, and motivations regarding genetic susceptibility testing for Alzheimer’s disease (AD). Before enrolling in an AD genetic testing research trial, 313 first-degree relatives of AD patients (20% African American; 71% female; mean age = 58 years) were surveyed regarding: (1) knowledge about genetics and AD risk; (2) concerns about developing AD; and (3) reasons for seeking testing. In comparison to Whites, African Americans were less knowledgeable about genetics and AD risk (p<.01) and less concerned about developing AD (p<.05), with lower levels of perceived disease risk (p=.04). The results suggest that African Americans and Whites differ notably in their knowledge, beliefs, and attitudes regarding genetic testing for AD. Additional research with more representative samples is needed to better understand these differences.
Genetic testing; African Americans; Alzheimer’s disease; APOE; Risk assessment; Susceptibility testing; Health beliefs; Health literacy; Health disparities
Alzheimer disease is the most common cause of dementia. It occurs worldwide and affects all ethnic groups. The incidence of Alzheimer disease is increasing due, in part, to increased life expectancy and the aging baby boomer generation. The average lifetime risk of developing Alzheimer disease is 10–12%. This risk at least doubles with the presence of a first-degree relative with the disorder. Despite its limited utility, patients express concern over their risk and, in some instances, request testing. Furthermore, research has demonstrated that testing individuals for apoli-poprotein E can be valuable and safe in certain contexts. However, because of the complicated genetic nature of the disorder, few clinicians are prepared to address the genetic risks of Alzheimer disease with their patients. Given the increased awareness in family history thanks to family history campaigns, the increasing incidence of Alzheimer disease, and the availability of direct to consumer testing, patient requests for information is increasing. This practice guideline provides clinicians with a framework for assessing their patients’ genetic risk for Alzheimer disease, identifying which individuals may benefit from genetic testing, and providing the key elements of genetic counseling for AD.
Alzheimer disease; dementia; guideline; genetic testing; genetic counseling
New genetic tests reveal risks for multiple conditions simultaneously, although little is understood about the psychological factors that affect testing uptake. We assessed a conceptual model called the Multiplex Genetic Testing Model (MGTM) using structural equation modeling (SEM). The MGTM delineates worry, perceived severity, perceived risk, response efficacy and attitudes toward testing as predictors of intentions and behavior. Participants were 270 healthy insured adults age 25–40 from the Multiplex Initiative conducted within a health care system in Detroit MI, USA. Participants were offered a genetic test that assessed risk for eight common health conditions. Confirmatory factor analysis revealed that worry, perceived risk and severity clustered into two disease domains: cancer or metabolic conditions. Only perceived severity of metabolic conditions was correlated with general response efficacy (β=0.13, p<0.05), which predicted general attitudes toward testing (β=0.24, p<0.01). Consistent with our hypothesized model, attitudes towards testing were the strongest predictors of intentions to undergo testing (β=0.49, p<0.01), which in turn predicted testing uptake (OR 17.7, β=0.97, p<0.01). The MGTM explained a striking 48% of the variance in intentions and 94% of the variation in uptake. These findings support use of the MGTM to explain psychological predictors of testing for multiple health conditions.
Genetic testing; Multiplex Initiative; health behavior; common disease; structural equation modeling; personalized medicine; U.S.A.
This study evaluates the extent to which psychological adaptation (validated measures of depressive symptoms, anxiety, and test-specific distress) after genetic susceptibility testing is influenced by changes in beliefs about Alzheimer's disease (AD) and sharing of test results with others. Adult children of AD patients (N=269) from a randomized clinical trial involving genetic testing for apolipoprotein E (APOE) provided information before, as well as 6 weeks and 12 months after results disclosure. The levels of adaptation varied highly among participants at 12-month assessment. Participants who learned that they were ɛ4 negative (lower risk) had a reduction in perceived risk and concern about developing AD compared with those who learned that they were ɛ4 positive. Those who received results through an extended educational protocol (three in-person visits) had a larger decline in AD concern than those in a condensed protocol (educational brochure and two in-person visits). Increase in AD concern 6 weeks after disclosure was associated with increase in depression scores (b=0.20, P<0.01) and anxiety levels (b=0.20, P<0.01), and higher distress associated with AD genetic testing (b=0.18, P=0.02) 1 year after testing. Increase in perceived risk (b=0.16, P=0.04) was also associated with higher AD genetic testing distress. Sharing the test results with health professionals and friends (but not family) was associated with decrease in depression (b = −0.11, P = 0.05) and anxiety levels (b=−0.16, P<0.01), respectively after a year. Enhancing discussion with regard to risks and concerns about AD during pretesting counseling and obtaining support through sharing the results after testing may help facilitate test recipients' long-term psychological adaptation.
susceptibility genetic testing; AD; APOE; results disclosure; communication; risk perceptions
This study examined understandings of basic genetic concepts among Americans.
In a national telephone survey of 1,200 Americans with equal representation among Black and White men and women, subjects responded to 8 items developed by a multidisciplinary team of experts that assessed understanding of basic concepts in multiple domains, including inheritance, genetics and race, and genetics and behavior.
Over 70% of subjects responded correctly on items about the genetic similarity of identical twins and siblings. Less than half of subjects responded correctly on all other items. Understanding of genetics was lowest in three areas: types/locations of genes in the body (29% correct), a genetic basis for race (25% correct), and the influence of single genes on behaviors (24% correct). Logistic regression models controlling for age and education showed some differences by race and gender on specific items but also showed that understandings are generally similar across these groups.
Misunderstandings about genetics are common among Black and White American men and women. Responses appear to reflect personal experiences, group values and interests. These findings emphasize the need for initiatives to improve the public's genetic literacy as well as a need for further investigation in this domain.
Gender; Genetic knowledge; Race; Survey; Understanding
Dietary (n-6)-polyunsaturated fatty acids influence cancer development, but the mechanisms have not been well characterised in gastric carcinoma.
We used two in vivo models to investigate the effects of these common dietary components on tumour metastasis. In a model of experimental metastasis, immunocompromised mice were fed diets containing linoleic acid (LA) at 2% (LLA), 8% (HLA) or 12% (VHLA) by weight and inoculated intraperitoneally (i.p.) with human gastric carcinoma cells (OCUM-2MD3). To model spontaneous metastasis, OCUM-2MD3 tumours were grafted onto the stomach walls of mice fed with the different diets. In in vitro assays, we investigated invasion and ERK phosphorylation of OCUM-2MD3 cells in the presence or absence of LA. Finally, we tested whether a cyclooxygenase (COX) inhibitor, indomethacin, could block peritoneal metastasis in vivo.
Both the HLA and VHLA groups showed increased incidence of tumour nodules (LA: 53% HLA: 89% VHLA: 100% P<0.03); the VHLA group also displayed increased numbers of tumour nodules and higher total volume relative to LLA group in experimental metastasis model. Both liver invasion (78%) and metastasis to the peritoneal cavity (67%) were more frequent in VHLA group compared with the LLA group (22% and 11%, respectively; P<0.03) in spontaneous metastasis model. We also found that the invasive ability of these cells is greatly enhanced when exposed to LA in vitro. Linoleic acid also increased invasion of other scirrhous gastric carcinoma cells, OCUM-12, NUGC3 and MKN-45. Linoleic acid effect on OCUM-2MD3 cells seems to be dependent on phosphorylation of ERK. The data suggest that invasion and phosphorylation of ERK were dependent on COX. Indomethacin decreased the number of tumours and total tumour volume in both LLA and VHLA groups. Finally, COX-1, which is known to be an important enzyme in the generation of bioactive metabolites from dietary fatty acids, appears to be responsible for the increased metastatic behaviour of OCUM-2MD3 cells in the mouse model.
Dietary LA stimulates invasion and peritoneal metastasis of gastric carcinoma cells through COX-catalysed metabolism and activation of ERK, steps that compose pathway potentially amenable to therapeutic intervention.
gastric carcinoma; dietary fatty acid; cyclooxygenase; metastasis; invasion
To perform a comprehensive population genetic study of PARK2. PARK2 mutations are associated with juvenile parkinsonism, Alzheimer disease, cancer, leprosy, and diabetes mellitus, yet ironically, there has been no comprehensive study of PARK2 in control subjects; and to resolve controversial association of PARK2 heterozygous mutations with Parkinson disease (PD) in a well-powered study.
We studied 1,686 control subjects (mean age 66.1 ± 13.1 years) and 2,091 patients with PD (mean onset age 58.3 ± 12.1 years). We tested for PARK2 deletions/multiplications/copy number variations (CNV) using semiquantitative PCR and multiplex ligation-dependent probe amplification, and validated the mutations by real-time quantitative PCR. Subjects were tested for point mutations previously. Association with PD was tested as PARK2 main effect, and in combination with known PD risk factors: SNCA, MAPT, APOE, smoking, and coffee intake.
A total of 0.95% of control subjects and 0.86% of patients carried a heterozygous CNV mutation. CNV mutations found in 16 control subjects were all in exons 1–4, sparing exons that encode functionally critical protein domains. Thirteen patients had 2 CNV mutations, 5 had 1 CNV and 1 point mutation, and 18 had 1 CNV mutation. Mutations found in patients spanned exons 2–9. In whites, having 1 CNV was not associated with increased risk (odds ratio 1.05, p = 0.89) or earlier onset of PD (64.7 ± 8.6 heterozygous vs 58.5 ± 11.8 normal).
This comprehensive population genetic study in control subjects fills the void for a PARK2 reference dataset. There is no compelling evidence for association of heterozygous PARK2 mutations, by themselves or in combination with known risk factors, with PD.
= autosomal recessive juvenile parkinsonism;
= confidence interval;
= copy number variation;
= moving average plots;
= multiplex ligation-dependent probe amplification;
= NeuroGenetics Research Consortium;
= odds ratio;
= Parkinson disease.
Perceptions about the pros and cons of genetic susceptibility testing are among the best predictors of test utilization. How actual testing changes such perceptions has yet to be examined.
In a clinical trial, first-degree relatives of patients with Alzheimer disease received genetic risk assessments for Alzheimer disease including APOE disclosure. Participants rated 11 possible benefits associated with genetic testing (pros) and 10 risks or limitations (cons) before genetic risk disclosure and again 12 months afterward.
Pros were rated higher than cons at baseline (3.53 vs. 1.83, P < 0.001) and at 12 months after risk disclosure (3.33 vs. 1.88, P < 0.001). Ratings of pros decreased during the 12-month period (3.33 vs. 3.53, P < 0.001). Ratings of cons did not change (1.88 vs. 1.83, P = 0.199) except for a three-item discrimination subscale which increased (2.07 vs. 1.92, P = 0.012). Among specific pros and cons, three items related to prevention and treatment changed the most.
The process of APOE genetic risk assessment for Alzheimer disease sensitizes some to its limitations and the risks of discrimination; however, 1-year after disclosure, test recipients still consider the pros to strongly outweigh the cons.
Alzheimer; pros; cons; benefits; discrimination; genetics; risk; APOE; susceptibility testing; education
The obligations of researchers to disclose clinically and/or personally significant individual research results are highly debated, but few empirical studies have addressed this topic. We describe the development of a protocol for returning research results to participants at one site of a multicenter study of the genetic epidemiology of melanoma. Protocol development involved numerous challenges: (1) deciding whether genotype results merited disclosure; (2) achieving an appropriate format for communicating results; (3) developing education materials; (4) deciding whether to retest samples for additional laboratory validation; (5) identifying and notifying selected participants; and (6) assessing the impact of disclosure. Our experience suggests potential obstacles depending on researcher resources and the design of the parent study, but offers a process by which researchers can responsibly return individual study results and evaluate the impact of disclosure.
genetic testing; cancer; CDKN2A; risk communication; return of research results; protocol development
To assess how neurologists view mild cognitive impairment (MCI) as a clinical diagnosis and how they treat patients with mild cognitive symptoms.
Members of the American Academy of Neurology with an aging, dementia, or behavioral neurology practice focus were surveyed by self-administered questionnaire.
Survey respondents were 420 providers (response rate 48%), and 88% reported at least monthly encounters with patients experiencing mild cognitive symptoms. Most respondents recognize MCI as a clinical diagnosis (90%) and use its diagnostic code for billing purposes (70%). When seeing these patients, most respondents routinely provide counseling on physical (78%) and mental exercise (75%) and communicate about dementia risk (63%); fewer provide information on support services (27%) or a written summary of findings (15%). Most (70%) prescribe cholinesterase inhibitors at least sometimes for this population, with memantine (39%) and other agents (e.g., vitamin E) prescribed less frequently. Respondents endorsed several benefits of a diagnosis of MCI: 1) involving the patient in planning for the future (87%); 2) motivating risk reduction activities (85%); 3) helping with financial planning (72%); and 4) prescribing medications (65%). Some respondents noted drawbacks, including 1) too difficult to diagnose (23%); 2) better described as early Alzheimer disease (21%); and 3) diagnosis can cause unnecessary worry (20%).
Patients with mild cognitive symptoms are commonly seen by neurologists, who view MCI as a useful diagnostic category. Information and treatments provided to patients with MCI vary significantly, suggesting a need for practice guidelines and further research on clinical decision-making with this population.
= age-associated memory impairment;
= American Academy of Neurology;
= Alzheimer disease;
= cognitive impairment, no dementia;
= Diagnostic and Statistical Manual of Mental Disorders, 5th edition;
= mild cognitive impairment;
= not otherwise specified.
With Alzheimer’s disease increasing in prevalence and public awareness, more people are becoming interested in learning their chances of developing this condition. Disclosing Alzheimer’s disease risk has been discouraged because of the limited predictive value of available tests, lack of prevention and treatment options, and concerns regarding potential psychological and social harms. However, challenges to this status quo include the availability of direct-to-consumer health risk information (e.g., genetic susceptibility tests), as well as a growing literature suggesting that people seeking risk information for Alzheimer’s disease through formal education and counseling protocols generally find it useful and do not experience adverse effects. This paper reviews current and potential methods of risk assessment for Alzheimer’s disease, discusses the process and impact of disclosing risk to interested patients and consumers, and considers the practical and ethical challenges in this emerging area. Anticipated future directions are addressed.
Alzheimer’s disease; genetic testing; risk assessment; risk communication
The association of elevated serum uric acid with the development of hypertension is established outside of pregnancy. We investigated whether first trimester uric acid was associated with the development of the following: gestational hypertension or preeclampsia, these outcomes stratified by presence of hyperuricemia at delivery since this denotes more severe disease, preterm birth or small for gestational age (SGA).
Uric acid was measured in 1541 banked maternal plasma samples from a prior prospective cohort study that were collected at a mean gestational age of 9.0 (± 2.5) weeks. Polytomous regressions were performed and adjusted for parity and pre-pregnancy body mass index.
First trimester uric acid in the highest quartile (>3.56 mg/dL) compared to lowest three quartiles was associated with an increased risk of developing preeclampsia (adjusted OR = 1.82; 95% CI, 1.03–3.21) but not gestational hypertension. In women with hypertensive disease complicated by hyperuricemia at delivery, high first trimester uric acid was associated with a 3.22-fold increased risk of hyperuricemic gestational hypertension and a 3.65-fold increased risk of hyperuricemic preeclampsia. High first trimester uric acid was not associated with gestational hypertension or preeclampsia without hyperuricemia at delivery, preterm birth, or SGA. In women who developed hypertensive disease, elevated uric acid at delivery was only partly explained by elevated uric acid in the first trimester (r2 = .23).
First trimester elevated uric acid was associated with later preeclampsia and more strongly with preeclampsia and gestational hypertension with hyperuricemia.
gestational hypertension; hyperuricemia; preeclampsia; uric acid
To estimate the prevalence of successful aging in the United States, with the broad aim of contributing to the dialogue on Rowe and Kahn’s concept of successful aging.
Using data from the Health and Retirement Study, the prevalence of successful aging was calculated for adults aged 65 years and older at four time points: 1998, 2000, 2002, and 2004. Successful aging was operationalized in accordance with Rowe and Kahn’s definition, which encompasses disease and disability, cognitive and physical functioning, social connections, and productive activities.
No greater than 11.9% of older adults were aging “successfully” in any year. The adjusted odds of successful aging were generally lower for those of advanced age, male gender, and lower socioeconomic status. Between 1998 and 2004, the odds of successful aging declined by 25%, after accounting for demographic changes in the older population.
Few older adults meet the criteria put forth in Rowe and Kahn’s definition of successful aging, suggesting the need for modification if the concept is to be used for broad public health purposes. Disparities in successful aging were evident for socially defined subgroups, highlighting the importance of structural factors in enabling successful aging.
Health disparities; Healthy aging; Prevalence; Successful aging
Use of high ultrafiltrate flow rates with continuous venovenous hemofiltration (CVVHF) in critically ill patients is an emerging setting, for which there are few data to guide drug dosing. The objectives of this study were, firstly, to investigate the pharmacokinetics of meropenem in critically ill patients with severe sepsis who are receiving high-volume CVVHF with high-volume exchanges (≥4 liters/h); secondly, to determine whether standard dosing regimens (1,000 mg intravenously [i.v.] every 8 h) are sufficient for treatment of less susceptible organisms such as Burkholderia pseudomallei (MIC, 4 mg/liter); and, finally, to compare the clearances observed in this study with data from previous studies using lower-volume exchanges (1 to 2 liters/h). We recruited 10 eligible patients and collected serial pre- and postfilter blood samples and ultrafiltrate and urine samples. A noncompartmental method was used to determine meropenem pharmacokinetics. The cohort had a median age of 56.6 years, a median weight of 70 kg, and a median APACHE II (acute physiology and chronic health evaluation) score of 25. The median (interquartile range) values for meropenem were as follows: terminal elimination half-life, 4.3 h (2.9 to 6.0); terminal volume of distribution, 0.2 liters/kg (0.2 to 0.3); trough concentration, 7.7 mg/liter (6.2 to 12.9); total clearance, 6.0 liters/h (5.2 to 6.2); hemofiltration clearance, 3.5 liters/h (3.4 to 3.9). In comparing the meropenem clearance here with those in previous studies, ultrafiltration flow rate was found to be the parameter that accounted for the differences in clearance of meropenem (R2 = 0.89). In conclusion, high-volume CVVHF causes significant clearance of meropenem, necessitating steady-state doses of 1,000 mg every 8 h to maintain sufficient concentrations to treat less susceptible organisms such as B. pseudomallei.
This study explored the extent to which recipients of genetic susceptibility testing for Alzheimer’s disease (AD) communicated their results to others. It also examined demographic characteristics, along with beliefs about AD, associated with such communication. Participants (N = 271) in a randomized clinical trial involving genetic testing for Apolipoprotein E (APOE) gene variants among first-degree relatives of AD patients reported their communication behaviors 6 weeks after the results disclosure. Information on beliefs about AD and genetic testing was collected at baseline. Eighty-two percent of participants receiving APOE genotype information shared their results with someone. Specifically, 64% shared with family members, 51% with spouse or significant others, 35% with friends, and 12% with health care professionals. Greater AD treatment optimism was associated with communicating results to family (OR=1.43), spouse (OR=1.62), friends (OR =1.81), and health care professionals (OR=2.20). Lower perceived risk (OR=0.98) and higher perceived importance of genetics in the development of AD (OR=1.93) were associated with results communication in general. Lower perceived drawbacks of AD genetic testing was associated with results communication to friends (OR=0.65). Beliefs about AD risks and causes, genetic testing, and development of treatments may partly determine the interpersonal communication patterns of genetic susceptibility test results.
Susceptibility genetic testing; Alzheimer’s disease; APOE communication; disclosure
This study evaluates the extent to which psychological adaptation (validated measures of depressive symptoms, anxiety, and test-specific distress) after genetic susceptibility testing is influenced by changes in beliefs about Alzheimer's disease (AD) and sharing of test results with others. Adult children of AD patients (N=269) from a randomized clinical trial involving genetic testing for apolipoprotein E (APOE) provided information before, as well as 6 weeks and 12 months after results disclosure. The levels of adaptation varied highly among participants at 12-month assessment. Participants who learned that they were ε4 negative (lower risk) had a reduction in perceived risk and concern about developing AD compared with those who learned that they were ε4 positive. Those who received results through an extended educational protocol (three in-person visits) had a larger decline in AD concern than those in a condensed protocol (educational brochure and two in-person visits). Increase in AD concern 6 weeks after disclosure was associated with increase in depression scores (b=0.20, P<0.01) and anxiety levels (b=0.20, P<0.01), and higher distress associated with AD genetic testing (b=0.18, P=0.02) 1 year after testing. Increase in perceived risk (b=0.16, P=0.04) was also associated with higher AD genetic testing distress. Sharing the test results with health professionals and friends (but not family) was associated with decrease in depression (b= −0.11, P=0.05) and anxiety levels (b= −0.16, P<0.01), respectively after a year. Enhancing discussion with regard to risks and concerns about AD during pretesting counseling and obtaining support through sharing the results after testing may help facilitate test recipients' long-term psychological adaptation.
susceptibility genetic testing; AD; APOE; results disclosure; communication; risk perceptions