Identification and validation of control cell lines for accurate parkin dosage analysis

Mutation of the parkin gene (parkin) is the most common cause of early-onset Parkinson's disease and to date over 100 different mutations have been described. However, screening of parkin is complicated by its genomic architecture and context. Notably, dosage alterations in parkin account for greater than 50% of mutations detected in some cohort studies. To improve the accuracy and reproducibility of parkin genomic dosage assays we have identified and analysed cell lines with chromosomal abnormalities affecting 6q26. FISH and real-time PCR analysis identified cell lines with reduced or increased copy number spanning the entire parkin locus. These cell lines represent a valuable resource to facilitate accurate copy number determination of any parkin exon. The reagents are easily obtainable and are compatible with current quantitative technologies and platforms.     

The pharmacological chaperone 1-deoxynojirimycin increases the activity and lysosomal trafficking of multiple mutant forms of acid alpha-glucosidase

Pompe disease is a lysosomal storage disorder (LSD) caused by mutations in the gene that encodes acid α-glucosidase (GAA). Recently, small molecule pharmacological chaperones have been shown to increase protein stability and cellular levels for mutant lysosomal enzymes and have emerged as a new therapeutic strategy for the treatment of LSDs. In this study, we characterized the pharmacological chaperone 1-deoxynojirimycin (DNJ) on 76 different mutant forms of GAA identified in Pompe disease. DNJ significantly increased enzyme activity and protein levels for 16 different GAA mutants in patient-derived fibroblasts and in transiently transfected COS-7 cells. Additionally, DNJ increased the processing of these GAA mutants to their mature lysosomal forms, suggesting facilitated trafficking through the secretory pathway. Immunofluorescence microscopy studies showed increased colocalization of GAA with the lysosomal marker LAMP2 after incubation with DNJ, confirming increased lysosomal trafficking. Lastly, a GAA structural model was constructed based on the related eukaryotic glucosidase maltase-glucoamylase. The mutated residues identified in responsive forms of GAA are located throughout most of the structural domains, with half of these residues located in two short regions within the catalytic domain. Taken together, these data support further evaluation of DNJ as a potential treatment for Pompe disease in patients that express responsive forms of GAA. Hum Mutat 30:1–10, 2009. © 2009 Wiley-Liss, Inc.     

Identification and Management of Women at High Risk for Hereditary Breast/Ovarian Cancer Syndrome

Abstract:  Despite advances in identifying genetic markers of high risk patients and the availability of genetic testing, it remains challenging to efficiently identify women who are at hereditary risk and to manage their care appropriately. HughesRiskApps, an open-source family history collection, risk assessment, and Clinical Decision Support (CDS) software package, was developed to address the shortcomings in our ability to identify and treat the high risk population. This system is designed for use in primary care clinics, breast centers, and cancer risk clinics to collect family history and risk information and provide the necessary CDS to increase quality of care and efficiency. This paper reports on the first implementation of HughesRiskApps in the community hospital setting. HughesRiskApps was implemented at the Newton-Wellesley Hospital. Between April 1, 2007 and March 31, 2008, 32,966 analyses were performed on 25,763 individuals. Within this population, 915 (3.6%) individuals were found to be eligible for risk assessment and possible genetic testing based on the 10% risk of mutation threshold. During the first year of implementation, physicians and patients have fully accepted the system, and 3.6% of patients assessed have been referred to risk assessment and consideration of genetic testing. These early results indicate that the number of patients identified for risk assessment has increased dramatically and that the care of these patients is more efficient and likely more effective.     

Euglycemic hyperinsulinemia alters the response to orthostatic stress in older adults with type 2 diabetes

OBJECTIVE—Insulin has opposing influences on blood pressure by simultaneously increasing adrenergic activity and vasodilatating peripheral blood vessels. In this study, we sought to determine whether hyperinsulinemia affects tilt table responses in older adults with type 2 diabetes not complicated by orthostatic hypotension.RESEARCH DESIGN AND METHODS—Twenty-two older adults (mean age 71.7 ± 1.1) with diet-controlled or oral hypoglycemic drug–controlled type 2 diabetes were recruited. All subjects with orthostatic hypotension, diabetic nephropathy, and sensory neuropathy were excluded. Subjects underwent euglycemic-hyperinsulinemic clamp and placebo “sham clamp” sessions. Sequential euglycemic-hyperinsulinemic clamps were performed for 2 h at 40 mU · m⁻² · min⁻¹ (low dose) and 2 h at 80 mU · m⁻² · min⁻¹ (high dose), and each was followed by a head-up tilt table test at 70°C for 10 min.RESULTS—There were no incidents of presyncope during the sham clamp, whereas there were four presyncopal events during both the low-dose and high-dose tilts. Although the low-dose clamp showed no difference in the response between sessions (two-way ANOVA), subjects demonstrated a significantly larger decrease in mean arterial pressure (P = 0.005) and diastolic blood pressure (P = 0.08) during the high-dose tilt. Doppler measures of middle cerebral artery velocity were no different between the two sessions at either dose.CONCLUSIONS—The vasodilatory response to insulin can unmask orthostatic intolerance in older adults with type 2 diabetes, resulting in presyncopal symptoms. This could contribute to orthostatic hypotension in combination with other factors such as hyperthermia, hypovolemia, and adverse effects from medications.Orthostatic hypotension is common in older adults with (1) and without diabetes (2) and is usually attributed to autonomic neuropathy or age-related comorbidities (3). Insulin has profound cardiovascular properties, resulting in simultaneous adrenergic (4) and vasodilatory (5,6) responses that have opposing influences on blood pressure. Depending on the relative magnitude of sympathetic activation and vasodilation in older adults, insulin administration might be a contributing factor in orthostatic intolerance and syncope.Epidemiological studies have demonstrated that the use of insulin is a risk factor for syncope in older adults (7) and that insulin hypersensitivity is a predisposing factor for vasovagal syncope in young women (8). Previous work in young adults with type 1 diabetes has shown that insulin has no impact on standing blood pressure unless their diabetes is already complicated by autonomic neuropathy (9). However, the aging process itself is associated with a reduction in adrenergic sensitivity (10). Insensitivity to an insulin-mediated increase in adrenergic activity could allow the vasodilatory response to predominate and potentially uncover “latent” orthostatic hypotension in older adults with uncomplicated diabetes, similar to that demonstrated previously in young hyperthermic adults with diabetes (11).In the current study, we examined in older adults with type 2 diabetes (without baseline orthostatic hypotension) the impact of hyperinsulinemia (12) on arterial blood pressure and Doppler measures of cerebral blood flow during upright tilt. We hypothesized that in older adults with type 2 diabetes, the cardiovascular effects of insulin would precipitate orthostatic intolerance not present at baseline.     

Reflexology for symptom relief in patients with cancer

Complementary therapies are increasingly being used in hospices and hospitals alongside orthodox treatments in an attempt to improve patients' emotional, spiritual, psychological, and physical well-being. An average of 31% of UK patients with cancer use some form of complementary therapy. Many UK cancer centers, out-patient units, and hospices are providing complementary services. There is strong anecdotal evidence that complementary therapies assist in the palliation of physical and psychological symptoms. This systematic review examines the research evidence base for the effectiveness of reflexology in cancer care. The study reports the results of a systematic review following the Cochrane principles of systematic reviewing. No meta-analysis was possible. Studies were retrieved from a comprehensive search of electronic databases from their start dates. An initial search was carried out in 2003 and updated in 2005 to 2006. Eligible studies were randomized controlled trials, controlled before and after studies, and interrupted time-series studies. Participants were adults with a diagnosis of cancer, receiving care in any healthcare setting. Interventions were limited to reflexology carried out by a qualified therapist as distinguished from another healthcare professional carrying out a reflexology intervention. Outcome measures were patient-reported levels of physical and psychological indices of symptom distress and quality of life (measured using validated assessment tools).     

Temporal trends of mercury, cesium, potassium, selenium, and thallium in Arctic char (Salvelinus alpinus) from Lake Hazen, Nunavut, Canada: effects of trophic position, size, and age

Arctic char (Salvelinus alpinus L.), the top predator in High Arctic lakes, often is used as a bioindicator of Hg contamination in Arctic aquatic ecosystems. The present study investigated effects of trophic position, size, and age of Arctic char in Lake Hazen, the largest lake in the Canadian High Arctic (81 degrees 50'N, 70 degrees 25'W), on Hg bioaccumulation. In addition, several essential (Se, K) and nonessential elements (Tl, Cs) in char muscle tissue were examined to compare their behavior to that of Hg. Trophic position of Arctic char was identified by stable isotope (delta15N) signature. Temporal trends of Hg from seven sampling campaigns over a 16-year period (1990-2006) were investigated for the overall data and for one trophic class. Concentrations of Hg were not correlated with age but were positively related to fork length and trophic position. Large char with greater delta15N signatures (> 12 per thousand) had larger Hg concentrations (0.09-1.63 microg/g wet wt) than small char with smaller delta15N signatures (< 12 per thousand, 0.03-0.32 microg/g wet wt), indicating that Hg concentrations increased with trophic position. Nonessential Cs and Tl showed relationships to age, length, and trophic position similar to those of Hg, indicating their potential to bioaccumulate and biomagnify. Essential Se and K did not show these relationships. Concentrations of Hg were adjusted using delta15N, leading to less within-year variability and a more consistent temporal trend. The delta15N-adjusted trend showed no decline of Hg in Arctic char from Lake Hazen (1990-2006) in the overall data set and in the small morphotype. Trends for the same period before the adjustment were not significant for the overall data set, but a slight decrease was apparent in the small morphotype. The results confirm the need to consider trophic position and fish size when monitoring temporal trends of Hg, particularly for species with different morphotypes.