Linear Scaling DFT Calculations with Numerical Atomic Orbitals

We have recently developed a method to perform Density Functional Theory calculations in systems with a very large number of atoms, which is based on the use of numerical atomic orbitals as basis sets. The method incorporates Order-N techniques both in the calculation of the Kohn-Sham hamiltonian matrix elements and in the solution of the wave functions, which make the CPU time and memory to scale linearly with the number of atoms, allowing calculations in very large system. In this work, we present results on several test systems to show that the approach and the basis sets used with our method are able to provide an accuracy similar to that of other standard DFT techniques.

Atlas-based segmentation for globus pallidus internus targeting on low-resolution MRI

In this paper we report a method to automatically segment the internal part of globus pallidus (GPi) on the pre-operative low-resolution magnetic resonance images (MRIs) of patients affected by Parkinson's disease. Herein we used an ultra-high resolution human brain dataset as electronic atlas of reference on which we segmented the GPi. First, we registered the ultra-high resolution dataset on the low-resolution dataset using a landmarks-based rigid registration. Then an affine and a non-rigid surface-based registration guided by the structures that surround the target was applied in order to propagate the labels of the GPi on the low-resolution un-segmented dataset and to accurately outline the target. The mapping of the atlas on the low-resolution MRI provided a highly accurate anatomical detail that can be useful for localizing the target.

Abstract P3-12-11: Combining Genotype at Low Penetrance Breast Cancer Loci with Family History Risk Leads to Significant Risk Reclassification

Background: A significant proportion of women are at increased genetic risk of breast cancer. Mutations in high penetrance genes such as BRCA1 and BRCA2 are only responsible in the minority of cases, with low penetrance polymorphisms in other genes expected to account for the majority of the remaining genetic risk. An increasing number of such low penetrance polymorphisms are being identified, but each polymorphism only contributes a small amount to overall risk. Currently, in clinical practice, women who are at increased risk of breast cancer are identified by their family history, and the role of genetic testing for multifactorial risk remains uncertain. We have taken the population frequency and genotype relative risk information for the 18 most established low penetrance breast cancer risk loci and explored the effect of combining information from these loci, with risk derived from family history. Results: Genotyping at these 18 loci could provide significant risk information for an individual. The top 1% of women in the genotype risk distribution would have a risk of breast cancer of 2.11 times the general population. At this level of risk, they would qualify for breast cancer screening from age 40 according to evidence based guidelines issued by the UK National Institute of Clinical Excellence (NICE). In addition, the top 5% of the population are at 1.67 times risk of breast cancer and would have the same risk at age 40 as a 50 year old at population risk who would qualify for breast screening according to UK and US National Screening Guidelines. To investigate whether low penetrance genotype has greater potential if combined with other risk factors, we used a simple multiplicative model to combine family history risk of cancer derived using BOADICEA with genotype information. Our data suggest that genotype would result in a significant reclassification of individual risk. For example, 10% of women who only had a sister affected with breast cancer at 55 would qualify for additional screening under NICE criteria if genotype were taken into account. Extending this approach with 160 complex family histories from the Tayside family history breast clinic, we have shown that genotyping could result in reclassification and change of management for 19.1% of women being assessed in this clinic, with 12.4% of women moving into a higher risk category, and 6.7% of women moving into a lower category. Discussion: These data suggest that genotyping for low penetrance breast cancer risk loci is clinically relevant, and that it will be more powerful if it can be combined with other established risk factors.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-12-11.

Preventing excessive gestational weight gain: a systematic review of interventions

Women who gain excessive weight during pregnancy have an increased risk of post-partum obesity, and retention of gestational weight gain (GWG) post birth is a strong predictor of maternal overweight/obesity a decade or more after the birth. The aim of the current review was to identify, and evaluate the effect of key variables designed to modify risk factors for excessive weight gain in pregnant women that have been targeted in interventions over the last decade. The 10 interventions focused primarily on behavioural changes in relation to physical activity and/or to eating. While six studies reported significantly less weight gain in the intervention women, only three showed that women in the intervention were significantly more likely to gain within recommended guidelines. GWG was reduced in only normal-weight, low-income, obese, or overweight women, or not at all. Only one study reported a reduction in GWG in women with body mass indexes spanning the normal, overweight and obese categories. The findings were inconsistent in relation to what factors need to be targeted in intervention programmes to reduce GWG. Consideration of psychological factors relevant to pregnancy, in addition to behavioural changes in relation to eating and physical activity, is suggested for future intervention studies.

Characteristics of inpatient psychiatric units in small rural hospitals

OBJECTIVES

This study investigated inpatient psychiatric units in small rural hospitals to determine their characteristics, the availability of community-based services after discharge, and the impact of the new Medicare payment system on these units.

METHODS

Unit managers in all rural hospitals with fewer than 50 beds that had a psychiatric unit in 2006 (N=74) were surveyed on the telephone.

RESULTS

On average these units had ten beds and 230 admissions per year. Medicare was the major payer (median of 84%). Typical staffing includes no more than one staff member from each category: psychiatrist, psychologist, social worker, counselor or therapist, and nurse practitioner. Common diagnoses reported were depression (74% of units), schizophrenia or other psychoses (42% of units), and dementia or Alzheimer's disease (57% of units).

CONCLUSIONS

Hospital staff reported little difficulty obtaining postdischarge care, and most staff clinicians provided outpatient services locally. Thus mental health services infrastructure appears better in these communities than in most rural communities, but it may be weakened by recent closures reported by some units, caused, in part, by changes in Medicare reimbursement.

Multimodal sensory testing of the rectum and rectosigmoid: development and reproducibility of a new method

Evaluation of rectal and rectosigmoid sensation is important in basic, clinical and pharmacological studies. New methods to evoke and assess multimodal (electrical, thermal and mechanical) experimental pain of the upper gut activate distinct pathways and mimics clinical pain. The aims of the current study were to characterize the sensory response and reproducibility to multimodal stimulation of rectum and the rectosigmoid. A multimodal rectal probe was developed. Mucosal electrostimulation was delivered at the recto-sigmoid junction. In Rectum, impedance planimetry was used for measurement of cross-sectional area (CSA) during distension. Circulation of water within the bag at either 4 or 60 degrees C was applied for thermal stimulation. The method was tested in 12 healthy volunteers (six men mean age 32 years) on two subsequent days. Mechanical and sensory responses and referred pain areas were assessed. Stimulation with electrical, thermal and mechanical modalities resulted in different sensory perceptions. The relationship between stimulus intensity and sensory response was linear for all modalities. Sensory response to different modalities did not differ between investigation days (all P-values > 0.1). Approximately 75% of subjects felt referred pain in distinct skin locations. Between-days reproducibility was good for all modalities [intra-class correlation (ICC) > or = 0.6]. At sensory threshold, CSA showed best reproducibility (ICC > or = 0.9). At pain detection threshold stretch ratio, CSA and electrostimulation showed best reproducibility (ICC = 1.0; 0.9; 0.9). The present model was easily implemented, robust and showed good reproducibility. It can be used to study pathophysiology or pharmacological interventions in healthy controls and in patients with diseases involving the distal hindgut.

Effects of a 5-HT(4) receptor agonist on oesophageal function and gastro-oesophageal reflux: studies using combined impedance-manometry and combined impedance-pH

BACKGROUND

5-HT(4) receptor agonists are used as promotility agents of the stomach, small and large intestine. There is limited information on the influence of 5-HT(4) receptor agonists on oesophageal function and gastro-oesophageal reflux.

AIM

To evaluate the effects of tegaserod, a 5-HT(4) agonist on oesophageal function using impedance-manometry and postprandial reflux using impedance-pH monitoring.

METHODS

Twenty healthy volunteers were enrolled in a double-blind randomized three-period crossover placebo-controlled study. Impedance-manometry and impedance-pH monitoring after a refluxogenic meal were performed at baseline and after 2 days of dosing with tegaserod 6 mg b.d. or placebo. Multichannel intraluminal impedance-EM recorded pressure and bolus transit data during standardized swallows. Multichannel intraluminal impedance-pH monitoring recorded the number of 2-h postprandial acid and non-acid reflux episodes.

RESULTS

We found no significant difference in distal oesophageal amplitude when subjects received placebo (median 94.5; range: 53-243 mmHg) or tegaserod (93.6; 43-216 mmHg). Bolus transit time was similar during dosing with placebo (7.1; 5.3-9.4 s) and tegaserod (7.2; 5.9-11.1 s). We observed similar numbers of acid and non-acid reflux episodes during dosing with placebo (5; 0-15 and 3; 0-18, respectively) and tegaserod (2; 0-11 and 4; 0-19, respectively).

CONCLUSION

Tegaserod, a 5-HT(4) receptor agonist does not change oesophageal motility and gastro-oesophageal reflux parameters in healthy volunteers.

Mechano-electrical transduction: new insights into old ideas

The gating-spring theory of hair cell mechanotransduction channel activation was first postulated over twenty years ago. The basic tenets of this hypothesis have been reaffirmed in hair cells from both auditory and vestibular systems and across species. In fact, the basic findings have been reproduced in every hair cell type tested. A great deal of information regarding the structural, mechanical, molecular and biophysical properties of the sensory hair bundle and the mechanotransducer channel has accumulated over the past twenty years. The goal of this review is to investigate new data, using the gating spring hypothesis as the framework for discussion. Mechanisms of channel gating are presented in reference to the need for a molecular gating spring or for tethering to the intra- or extracellular compartments. Dynamics of the sensory hair bundle and the presence of motor proteins are discussed in reference to passive contributions of the hair bundle to gating compliance. And finally, the molecular identity of the channel is discussed in reference to known intrinsic properties of the native transducer channel.

A randomized effectiveness trial of brief cognitive-behavioral therapy for depressed adolescents receiving antidepressant medication

OBJECTIVE

To test a collaborative-care, cognitive-behavioral therapy (CBT) program adjunctive to selective serotonin reuptake inhibitor (SSRI) treatment in HMO pediatric primary care.

METHOD

A randomized effectiveness trial comparing a treatment-as-usual (TAU) control condition consisting primarily of SSRI medication delivered outside the experimental protocol (n = 75) versus TAU SSRI plus brief CBT (n = 77). Participants were identified by a recent dispense of SSRI medication followed by telephone screening. Adolescents with a diagnosis of major depressive disorder (n = 152) were enrolled. The CBT program employed cognitive restructuring and/or behavioral activation training. Therapists consulted with prescribing pediatricians to improve medication adherence.

RESULTS

Through 1-year follow-up, the authors found CBT advantages on the Short Form-12 Mental Component Scale (p = .04), reductions in TAU outpatient visits (p = .02), and days' supply of all medications (p = .01). No effects were detected for major depressive disorder episodes; a nonsignificant trend favoring CBT was detected on the Center for Epidemiology Depression Scale (p = .07).

CONCLUSIONS

The authors detected a weak CBT effect, possibly rendered less significant by the small sample and likely attenuated by the unexpected reduction in SSRI pharmacotherapy in the CBT condition. Small, incremental improvements over monotherapy, such as observed in this study, most likely represent the new norm in adolescent depression treatment research.

Plants and altitude--revisited

The importance of modelling and the integration of all environmental factors as they change with time is emphasized in relation to the evaluation of plant response to altitude.

Small town health care safety nets: report on a pilot study

CONTEXT

Very little is known about the health care safety net in small towns, especially in towns where there is no publicly subsidized safety-net health care.

PURPOSE

This pilot study of the primary care safety net in 7 such communities was conducted to start building knowledge about the rural safety net.

METHODS

Interviews were conducted and secondary data collected to assess the community need for safety-net care, the health care safety-net role of public officials, and the availability of safety-net care at private primary care practices and its financial impact on these practices.

FINDINGS

An estimated 20% to 40% of the people in these communities were inadequately insured and needed access to affordable health care, and private primary care practices in most towns played an important role in making primary care available to them. Most of the physician practices were owned or subsidized by a hospital or regional network, though not explicitly to provide charity care. It is likely this ownership or support enabled the practices to sustain a higher level of charity care than would have been possible otherwise. In the majority of communities studied, the leading public officials played no role in ensuring access to safety-net care.

CONCLUSIONS

State and national government policy makers should consider subsidy programs for private primary care practices that attempt to meet the needs of the inadequately insured in the many rural communities where no publicly subsidized primary safety-net care is available. Subsidies should be directed to physicians in primary care shortage areas who provide safety-net care; this will improve safety-net access and, at the same time, improve physician retention by bolstering physician incomes. Options include enhanced Medicare physician bonuses and grants or tax credits to support income-related sliding fee scales.

Medicaid managed behavioral health in rural areas

As of 2000, 21 states had implemented Medicaid managed behavioral health (MMBH) programs for a significant portion of their rural population. It is not clear how MMBH programs may work in rural areas since they are primarily designed to control mental health utilization. In rural areas the challenge is often to enhance service delivery, not to reduce it. MMBH programs may also affect important features of rural delivery systems, including access to care and coordination of primary care and specialty mental health providers. This article describes the implementation of MMBH programs in rural areas based on an inventory of states implementing MMBH programs in rural counties conducted between June 1999 and June 2000. The experience of MMBH programs in rural areas is also described based on case studies conducted in six states. All 21 states included the general Medicaid population (Temporary Assistance for Needy Families); 17 states included special Medicaid populations (adults with serious and persistent mental illness and children with serious emotional disturbances). Slightly less than half the states integrated (carved-in) behavioral health with physical health services in serving the general Medicaid population; only one state integrated these services for the special Medicaid population. Access to mental health care in rural areas had generally not been restricted. MMBH had little impact on the linkage between primary care and mental health. Local Managed Behavioral Health Organizations, formed by public sector entities and providers, played an increasingly important role in the evolution of MMBH.

Use of psychotropic agents in preschool children: associated symptoms, diagnoses, and health care services in a health maintenance organization

BACKGROUND

Recent pharmacoepidemiological reports have contributed to concerns about frequent and perhaps indiscriminate psychopharmacotherapy for very young children.

OBJECTIVE

To examine the diagnoses, symptoms, and health care services associated with preschool children receiving psychotropic medication.

DESIGN

Population-based pharmacoepidemiological analysis of electronic medical records, paper medical and mental health charts, and pharmacy records from 1997 and 1998.

SETTING

A large Pacific Northwest health maintenance organization.

PARTICIPANTS

Preschool children receiving psychotropic medication (psychostimulants, antidepressants, neuroleptics, or alpha(2)-adrenergic agonists).

MEASURES

Physician-reported mental health diagnoses and related symptoms, functional impairment, family and participant characteristics, and the types and level of associated medical and mental health services.

RESULTS

Of 743 preschool children who clinicians identified as having behavioral or emotional problems, 120 (16%) received psychotropic medication; 57 children (48%) were prescribed a stimulant medication only, and 60 (50%) received a diagnosis of attention-deficit/hyperactivity disorder. Most children had substantial psychosocial risk factors, including parents with psychiatric or substance abuse problems (71%; n = 85), documented histories of abuse (29%; n = 35), and out-of-home placement (31%; n = 37). Four of 5 children or families (83%; n = 99) received psychosocial services in addition to pharmacotherapy. On average, children received psychotropic medication at least 6 months after initial identification of a behavioral or mental health problem.

CONCLUSIONS

Despite commentary by the popular media about widespread psychopharmacotherapy for very young children, such treatment was only infrequently received in this health plan. Most children receiving psychopharmacotherapy had substantial additional risk factors and were receiving psychosocial services for mental health or behavioral management.