Atom probe trajectory mapping using experimental tip shape measurements

Atom probe tomography is an accurate analytical and imaging technique which can reconstruct the complex structure and composition of a specimen in three dimensions. Despite providing locally high spatial resolution, atom probe tomography suffers from global distortions due to a complex projection function between the specimen and detector which is different for each experiment and can change during a single run. To aid characterization of this projection function, this work demonstrates a method for the reverse projection of ions from an arbitrary projection surface in 3D space back to an atom probe tomography specimen surface. Experimental data from transmission electron microscopy tilt tomography are combined with point cloud surface reconstruction algorithms and finite element modelling to generate a mapping back to the original tip surface in a physically and experimentally motivated manner. As a case study, aluminium tips are imaged using transmission electron microscopy before and after atom probe tomography, and the specimen profiles used as input in surface reconstruction methods. This reconstruction method is a general procedure that can be used to generate mappings between a selected surface and a known tip shape using numerical solutions to the electrostatic equation, with quantitative solutions to the projection problem readily achievable in tens of minutes on a contemporary workstation.

Muscle fiber size increases following resistance training in multiple sclerosis

Objective: To test the hypothesis that lower body progressive resistance training (PRT) leads to an increase of the muscle fiber cross-sectional area (CSA) and a shift in the proportion of fiber types in patients with multiple sclerosis (MS).

Methods: The present study was a two-arm, randomized controlled trial (RCT). Thirty-eight MS patients (Expanded Disability Status Scale (EDSS) 3—5.5) were randomized to a PRT group (Exercise, n = 19) or a control group (Control, n = 19). The Exercise group performed a biweekly 12-week lower body PRT program [five exercises progressing from 15RM (Repetition Maximum) towards 8RM], whereas the Control group maintained their usual daily activity level during the trial period. Muscle biopsies from vastus lateralis were taken before (pre) and after the trial (post). Thigh volume (TV) was estimated from anthropometric measurements. Isokinetic muscle strength of the knee extensors (KE) and flexors (KF) were evaluated at slow (90°/s) and fast (180°/s) angular velocities.

Results: In the Exercise group the mean CSA of all muscle fibers (7.9 ± 15.4% vs. -3.5 ± 9.0%, p = 0.03) and of type II muscle fibers (14.0 ± 19.4% vs. -2.6 ± 15.5%, p = 0.02) increased in comparison with the Control group. No changes occurred in the proportion of fiber types in the Exercise group. Neither was there any change in total TV. Isokinetic strength at KE180, KF90 and KF180 improved significantly after PRT when compared with the control group (10.2—21.3%, p ≤ 0.02).

Conclusions: We conclude that progressive resistance training induces a compensatory increase of muscle fiber size in patients with the central nervous system disorder, multiple sclerosis.

Fatigue, mood and quality of life improve in MS patients after progressive resistance training

Fatigue occurs in the majority of multiple sclerosis patients and therapeutic possibilities are few. Fatigue, mood and quality of life were studied in patients with multiple sclerosis following progressive resistance training leading to improvement of muscular strength and functional capacity. Fatigue (Fatigue Severity Scale, FSS), mood (Major Depression Inventory, MDI) and quality of life (physical and mental component scores, PCS and MCS, of SF36) were scored at start, end and follow-up of a randomized controlled clinical trial of 12 weeks of progressive resistance training in moderately disabled (Expanded Disability Status Scale, EDSS: 3—5.5) multiple sclerosis patients including a Control group ( n = 15) and an Exercise group ( n = 16). Fatigue (FSS > 4) was present in all patients. Scores of FSS, MDI, PCS—SF36 and MCS—SF36 were comparable at start of study in the two groups. Fatigue improved during exercise by —0.6 (95% confidence interval (CI) —1.4 to 0.4) a.u. vs. 0.1 (95% CI —0.4 to 0.6) a.u. in controls ( p = 0.04), mood improved by —2.4 (95% CI —4.1 to 0.7) a.u. vs. 1.1 (—1.2 to 3.4) a.u. in controls ( p = 0.01) and quality of life (PCS—SF36) improved by 3.5 (95% CI 1.4—5.7) a.u. vs. —1.0 (95% CI —3.4—1.4) a.u. in controls ( p = 0.01). The beneficial effect of progressive resistance training on all scores was maintained at follow-up after further 12 weeks. Fatigue, mood and quality of life all improved following progressive resistance training, the beneficial effect being maintained for at least 12 weeks after end of intervention.

Fatigued patients with multiple sclerosis have impaired central muscle activation

BACKGROUND

The pathogenesis of fatigue in multiple sclerosis (MS) is poorly understood.

OBJECTIVE

To elucidate the role of central motor activation we hypothesized that patients with primary fatigue have impaired central motor function and increased fatigability as compared to secondary fatigued and non-fatigued patients.

METHODS

Sixty patients with relapsing remitting MS and an Expanded Disability Status Scale score <or= 3.5 were recruited and grouped as fatigued (Fatigue Severity Scale (FSS) >or= 5.0) or non-fatigued (FSS <or= 4.0). Nineteen patients were primary fatigued, 20 secondary fatigued and 21 non-fatigued. Maximal voluntary contraction, central activation and peripheral activation were determined by percutaneous twitch interpolation of the right quadriceps muscle.

RESULTS

Maximal voluntary contraction was similar between groups but did relate to scores of fatigue. Peripheral activation was similar in all groups. Central activation was impaired in both groups of fatigued patients compared to non-fatigued patients being 0.96(0.05) in primary fatigued and 0.96(0.04) in secondary fatigued versus 0.99(0.1) in non-fatigued patients. The impairment of central motor activation was related to degree of fatigue in all patients. During fatiguing exercise there was a similar loss of strength, without any time differences between the three groups.

CONCLUSION

We conclude that impaired central motor activation is involved in MS-fatigue.

Stressful life events are associated with a poor in-vitro fertilization (IVF) outcome: a prospective study

BACKGROUND

There is preliminary evidence to suggest an impact of stress on chances of achieving a pregnancy with in-vitro fertilization (IVF). The majority of the available research has focused on stress related to infertility and going through IVF-treatment, and it is still unclear whether non-fertility-related, naturally occurring stressors may influence IVF pregnancy chances. Our aim was to explore the association between IVF-outcome and negative, i.e. stressful, life-events during the previous 12 months.

METHODS

Prior to IVF, 809 women (mean age: 31.2 years) completed the List of Recent Events (LRE) and questionnaires measuring perceived stress and depressive symptoms.

RESULTS

Women who became pregnant reported fewer non-fertility-related negative life-events prior to IVF (Mean: 2.5; SD: 2.5) than women who did not obtain a pregnancy (Mean: 3.0; SD: 3.0) (t(465.28) = 2.390, P = 0.017). Logistic regression analyses revealed that the number of negative life-events remained a significant predictor of pregnancy (OR: 0.889; P = 0.02), when controlling for age, total number of life-events, perceived stress within the previous month, depressive symptoms, and relevant medical factors related to the patient or treatment procedure, including duration of infertility, number of oocytes retrieved and infertility etiology. Mediation analyses indicated that the association between negative life events and IVF pregnancy was partly mediated by the number of oocytes harvested during oocyte retrieval.

CONCLUSION

A large number of life-events perceived as having a negative impact on quality of life may indicate chronic stress, and the results of our study indicate that stress may reduce the chances of a successful outcome following IVF, possibly through psychobiological mechanisms affecting medical end-points such as oocyte retrieval outcome.

Synergistic immune responses induced by endogenous retrovirus and herpesvirus antigens result in increased production of inflammatory cytokines in multiple sclerosis patients

Human endogenous retroviruses (HERV) and herpesviruses are increasingly associated with the pathogenesis of the neurological inflammatory disease multiple sclerosis (MS). Herpesviruses are capable of HERV activation and simultaneous presence of HERV and herpesvirus antigens have a synergistic effect on cell-mediated immune responses, which tend to be higher in MS patients in comparison with healthy individuals. Here, we investigate whether these synergistic immune responses are reflected in changes in the production of proinflammatory cytokines. Using enzyme-linked immunosorbent assays (ELISAs), we have performed a comparative study between MS patients and healthy controls to investigate the production of interferon (IFN)-gamma, interleukin (IL) 2, or IL-10 as well as the balance between Th1 and Th2 responses in supernatants from peripheral blood mononuclear cells (PBMC) stimulated with HERV and herpes antigen combinations. We have found a significant disproportion in Th1/Th2 responses in PBMCs from MS patients caused by the joint presence of HERV and herpes antigens. The results also showed a significantly higher IFN-gamma production in cells from MS patients; additionally, this production correlated with the synergistic cell proliferations whereas we did not find such a correlation in healthy controls. Our findings suggest that the increased production of IFN-gamma and the induced imbalance in Th1/Th2 responses favouring the inflammatory reactions in MS patients may lead to progression of the disease.

The antiproliferative effects of phenoxodiol are associated with inhibition of plasma membrane electron transport in tumour cell lines and primary immune cells

Although the redox-active synthetic isoflavene, phenoxodiol, is in Phase 3 clinical trials for drug-resistant ovarian cancer, and in early stage clinical trials for prostate and cervical cancer, its primary molecular target is unknown. Nevertheless, phenoxodiol inhibits proliferation of many cancer cell lines and induces apoptosis by disrupting FLICE-inhibitory protein, FLIP, expression and by caspase-dependent and -independent degradation of the X-linked inhibitor of apoptosis, XIAP. In addition, phenoxodiol sensitizes drug-resistant tumour cells to anticancer drugs including paclitaxel, carboplatin and gemcitabine. Here, we investigate the effects of phenoxodiol on plasma membrane electron transport (PMET) and cell proliferation in human leukemic HL60 cells and mitochondrial gene knockout HL60rho(o) cells that exhibit elevated PMET. Phenoxodiol inhibited PMET by both HL60 (IC(50) 32 microM) and HL60rho(o) (IC(50) 70 microM) cells, and this was associated with inhibition of cell proliferation (IC(50) of 2.8 and 6.7 microM, respectively), pan-caspase activation and apoptosis. Unexpectedly, phenoxodiol also inhibited PMET by activated murine splenic T cells (IC(50) of 29 microM) as well as T cell proliferation (IC(50) of 2.5 microM). In contrast, proliferation of WI-38 cells and HUVECs was only weakly affected by phenoxodiol. These results indicate that PMET may be a primary target for phenoxodiol in tumour cells and in activated T cells.

Cellular lifespan and regenerative medicine

Tissue engineering is a promising approach to aid in the treatment of a wide range of clinical disorders by developing replacement tissues for damaged or diseased organs. Such approaches, however, will require large and functional cell populations in order to produce a tissue that can replicate in vivo function. Most adult cells have limited replicative potential that limits their use in tissue engineering applications. Thus, cell populations with expanded lifespan or increased replicative potential are of interest. Stem cell-derived populations may allow the creation of large cell populations that have increased replicative potential over adult differentiated cells. In addition, ectopic human telomerase reverse transcriptase expression and induced B-cell lymphoma 2 (bcl-2) expression can allow adult cells to proliferate more extensively than unaltered cells. However, concerns for malignant transformation exist with telomerase and bcl-2 approaches. The current states of research in these areas are reviewed as they relate to tissue engineering and the cellular lifespan.

Electrical stimulation of sacral dermatomes in multiple sclerosis patients with neurogenic detrusor overactivity

AIMS

Transcutaneous electrical stimulation of the dorsal penile/clitoral nerve (DPN) has been shown to suppress detrusor contractions in patients with neurogenic detrusor overactivity (NDO). However, the long-term use of surface electrodes in the genital region may not be well tolerated and may introduce hygienic challenges. The aim of this study was to assess whether electrical stimulation of the sacral dermatomes could suppress detrusor contractions in multiple sclerosis (MS) patients with NDO, hereby providing an alternative to DPN stimulation.

MATERIALS AND METHODS

A total of 14 MS patients (8 M, 6 F) with low bladder capacity (<300 ml) and a recent urodynamic study showing detrusor overactivity incontinence participated in the study. Three successive slow fill cystometries (16 ml/min) were carried out in each patient. The first filling served as control filling where no stimulation was applied. In the second and third filling electrical stimulation of either the DPN or sacral dermatomes was applied automatically whenever the detrusor pressure exceeded 10 cmH2O.

RESULTS

The control filling showed detrusor overactivity in 12 of the 14 patients. In 10 of the 12 patients one or more detrusor contractions could be suppressed with DPN stimulation. Electrical stimulation of the sacral dermatomes failed to suppress detrusor contractions in all patients.

CONCLUSIONS

Although therapeutic effects may be present from stimulation of the sacral dermatomes, we were unable to demonstrate any acute effects during urodynamics. For this reason stimulation of the sacral dermatomes is not an option in a system that relies on the acute suppression of a detrusor contraction.

Nine-year single center experience with cervical mediastinoscopy: complications and false negative rate

BACKGROUND

Mediastinoscopy is a valuable tool for evaluating mediastinal pathology and is essential for establishing treatment strategies in most patients with lung cancer. We sought to determine the complication and false negative rate for mediastinoscopy in an institution that routinely performs this procedure.

METHODS

We performed a retrospective review of 2,145 consecutive mediastinoscopies at a single institution between April 1996 and April 2005. Demographics and complications were analyzed. In patients with lung cancer who underwent subsequent resection, the false negative rate was calculated.

RESULTS

Mean patient age was 61 +/- 0.4 years, and 58% (n = 1,253) were male. Pathology included lung cancer (n = 1,459), metastatic disease (n = 78), lymphoma (n = 51), and other benign disease (n = 557). Twenty-three patients (1.07%) experienced complications including hemorrhage (n = 7, 0.33%), vocal cord dysfunction (n = 12, 0.55%), tracheal injury (n = 2, 0.09%), and pneumothorax (n = 2, 0.09%). There was 1 death (0.05%) after pulmonary artery injury. Five of the 7 vascular injuries occurred during biopsy of level 4R. Three hundred and forty-three patients (23.5%) with lung cancer had positive mediastinoscopies. The false negative rate was 56 of 1,019 (5.5%) among lung cancer patients undergoing resection. Thirty-two (57%) of the false negatives were due to metastatic disease in lymph nodes not normally biopsied during cervical mediastinoscopy (levels 5, 6, 8, or 9).

CONCLUSIONS

Although invasive, mediastinoscopy identified locally advanced disease in a significant percentage of this lung cancer population and was associated with a low false negative rate. Complications after mediastinoscopy were uncommon. These results support the continued routine use of mediastinoscopy.

A randomized study of two interferon- beta treatments in relapsing–remitting multiple sclerosis

Objective: To investigate whether the efficacy of interferon-beta (IFNβ) treatment of relapsing–remitting MS (RR-MS) was influenced by type, dose, and frequency of administration.

Methods: From June 1996 through October 1997, the authors offered participation to all Danish RR-MS patients who met the following criteria: definite MS, at least two relapses within 2 years, age 18 to 55, and an Expanded Disability Status Scale (EDSS) score of ≤5.5. The study was multicenter, controlled, open-label, randomized, head-to-head comparing IFNβ-1a 22 μg once a week (n = 143) with IFNβ-1b 250 μg every other day (n = 158), both subcutaneously, for 24 months. Patients who declined randomization were offered treatment with IFNβ-1b 250 μg every other day (n = 120). The primary end-points were the annualized relapse rate, the time to first relapse, and neutralizing antibody formation. The secondary endpoint was time to sustained progression

Results: The annual relapse rates were virtually equal in the two arms of the randomized study (IFNβ-1a: 0.70; IFNβ-1b: 0.71); so were the time to first relapse and the time to sustained progression. In the nonrandomized patients (IFNβ-1b), the annual relapse rate was not significantly different, but the time to progression was shorter.

Conclusion: In this study, 250 μg interferon-beta-1b administered every other day did not prove clinically superior to once-a-week administration of 22 μg interferon-beta-1a.

Continuation cognitive-behavioural therapy maintains attributional style improvement in depressed patients responding acutely to fluoxetine

BACKGROUND

Little is known about how continuation and maintenance cognitive-behavioural therapy (CBT) influences important psychological constructs that may be associated with long-term outcome of major depressive disorder. The goal of this study was to examine whether CBT would help maintain attributional style changes experienced by patients during acute phase fluoxetine treatment.

METHOD

Three hundred and ninety-one patients with major depressive disorder were enrolled in an open, fixed-dose 8 week fluoxetine trial. Remitters to this acute phase treatment (N= 132) were randomized to receive either fixed-dose fluoxetine (meds only) or fixed-dose fluoxetine plus cognitive-behavioural therapy (CBT+meds) during a 6-month continuation treatment phase. The Attributional Style Questionnaire (ASQ) was completed by patients at three time points - acute phase baseline, continuation phase baseline and continuation phase endpoint. Analysis of covariance was used to compare continuation phase ASQ composite score changes between groups.

RESULTS

Patients in both treatment groups experienced significant gains in positive attributional style during the acute phase of treatment. Continuation phase ASQ composite change scores differed significantly between treatment groups, with the CBT + meds group maintaining acute phase positive attributional style changes, and the meds only group exhibiting a worsening of attributional style. The two treatment groups did not significantly differ in rates of relapse and final continuation phase visit HAMD-17 scores.

CONCLUSIONS

In this sample, the addition of CBT to continuation psychopharmacological treatment was associated with maintenance of acute treatment phase attributional style gains. Further research is needed to evaluate the role of such gains in the long-term course of depressive illness.

Bilateral LMAN lesions cancel differences in HVC neuronal recruitment induced by unilateral syringeal denervation. Lateral magnocellular nucleus of the anterior neostriatum

Twenty-six-day-old male zebra finches received (1) unilateral section of their tracheosyringeal nerve, (2) bilateral lesions of the lateral magnocellular nucleus of the anterior neostriatum (LMAN), and (3) both operations. All birds were kept with an adult, singing male as a tutor until day 65. Tracheo-syringeal nerve-cut birds were able to imitate this model, but LMAN-lesioned birds were not. Bromodeoxyuridine, a marker of cell division, was injected intramuscularly during post-hatching days 61-65 and all birds were killed at 91 days of age. The number of bromodeoxyuridine+ neurons in the high vocal center of the tracheosyringeal-cut birds was twice as high in the intact as in the nerve cut side. This asymmetry disappeared when nerve section was combined with bilateral LMAN lesions. The latter operation, by itself, had no effect on new neuron counts. We suggest that the single nerve cut produced a hemispheric asymmetry in learning, reflected in new neuron recruitment, which disappeared when LMAN lesions blocked learning.

A survey of prescribing preferences in the treatment of refractory depression: recent trends

The objective of this study was to gather data from a large group of clinicians on antidepressant prescribing practices in the treatment of refractory depression. Eight hundred and thirty-five clinicians about to attend the annual Massachusetts General Hospital psychopharmacology review course were asked to respond to a brief questionnaire regarding a hypothetical clinical case vignette. The case was of a patient who suffered from a new onset, unipolar, nonpsychotic, severe major depressive episode. Three hundred and four (36%) clinicians agreed to participate and filled out our questionnaire. Of the respondents, 260 (85.5%) indicated their preference for an initial treatment that combined medication and psychotherapy, as opposed to either modality alone. Furthermore, given this patient's nonresponse to two adequate selective serotonin reuptake inhibitor (SSRI) trials and one atypical antidepressant trial over an 8-month period, 39.8% of respondents indicated venlafaxine monotherapy as their next choice, whereas combining antidepressants (20.1%) and augmentation (18.4%) were the second and third most preferred treatment choices at this time point. Further on in the course of treatment, with the patient not having responded to any interventions during a 16-month period, 80.9% of survey respondents indicated electroconvulsant therapy (ECT) as their next preference. Among 304 clinicians surveyed, a combination of therapy and medication is the most preferred choice for treating severely depressed outpatients with new onset depression. Switching to venlafaxine, using two antidepressants together, and augmentation of an antidepressant regimen with a second agent accounted for 78.3% of respondents' preferences when faced with treating a depressed patient who had not responded to two adequate SSRI trials and one adequate atypical antidepressant trial. Of the respondents, 80.9% indicated ECT as a treatment preference after 16 months of multiple failed medication trials and nonresponse to psychotherapy. Further research is necessary to elucidate the factors that influence clinicians' reasoning for selecting one strategy over another.

Use of the five-factory inventory in characterizing patients with major depressive disorder

Research on personality traits has suggested an association between depression and certain personality traits, such as neuroticism and extraversion. Costa and McCrae's five-factor personality inventory (NEO) has been shown to measure personality traits in a nonclinical population, but its use has not been fully explored in clinical populations. This study aims to compare NEO results in a sample of depressed outpatients with published test norms, and determine if different levels of neuroticism and extraversion are associated with differences in certain psychosocial and clinical characteristics. Seventy-six depressed outpatients participating in antidepressant clinical trials completed this self-report questionnaire before beginning pharmacological treatment. Diagnosis of major depressive disorder (MDD) was made using the Structured Clinical Interview for DSM-III-R or DSM-IV and the severity of depression was measured with the 17-item Hamilton Depression Rating Scale (HAM-D). The three analyses conducted were as follows: (1) NEO factor scores were compared with published normative means; (2) three groups, based on level of neuroticism, were compared on certain psychosocial and clinical characteristics; and (3) three groups, based on level of extraversion, were compared on the same psychosocial and clinical characteristics. Both the males and females obtained T score values for the Neuroticism Scale 1.5 SD above the mean, for the Extraversion Scale 1.5 SD below the mean, and for the Conscientiousness Scale 1.5 SD below the mean. No significant differences were found between subjects with different levels of neuroticism and extraversion, although a trend did exist indicating a positive relationship between neuroticism and severity of depression. Depressed outpatients experience frequent negative affects, have irrational thought processes, cope with stress poorly, have difficulty controlling impulses, prefer to be alone, and have difficulty carrying out tasks. Future studies should examine how such personality factors affect response to treatment and course of illness.

Treatment resistant depression and axis I co-morbidity

BACKGROUND

Treatment resistant depression (TRD) continues to present a formidable challenge to clinicians, accounts for over half of the annual costs associated with treatment for depression and causes great frustration to patients. Although there have been studies attempting to define TRD, little information is available as to the cause of TRD. One suggestion is that patients with TRD have a greater frequency of co-morbid psychiatric disorders, which explains their resistance to standard antidepressant treatments. The objective of this study was to compare the co-morbidity of Axis I disorders between a sample of TRD patients and a sample of non-TRD patients.

METHODS

TRD and non-TRD patients, recruited from two separate antidepressant treatment studies, were assessed for Axis I co-morbidity using the SCID-P for the DSM-III-R. Patients for the two samples were then matched for baseline HAM-D-17 total score and gender.

RESULTS

Results reveal that non-TRD patients had a higher rate of both lifetime and current generalized anxiety disorder co-morbidity than did the TRD patients. No other statistically significant differences in Axis I co-morbidity were found.

CONCLUSIONS

These findings do not support the idea that current or lifetime Axis I co-morbidity is more common in TRD than non-TRD patients. In fact, the only statistical difference showed non-TRD patients with higher co-morbidity rates.