Predictive model of spread of Parkinson's pathology using network diffusion

Growing evidence suggests that a "prion-like" mechanism underlies the pathogenesis of many neurodegenerative disorders, including Parkinson's disease (PD). We extend and tailor previously developed quantitative and predictive network diffusion model (NDM) to PD, by specifically modeling the trans-neuronal spread of alpha-synuclein outward from the substantia nigra (SN). The model demonstrated the spatial and temporal patterns of PD from neuropathological and neuroimaging studies and was statistically validated using MRI deformation of 232 Parkinson's patients. After repeated seeding simulations, the SN was found to be the most likely seed region, supporting its unique lynchpin role in Parkinson's pathology spread. Other alternative spread models were also evaluated for comparison, specifically, random spread and distance-based spread; the latter tests for Braak's original caudorostral transmission theory. We showed that the distance-based spread model is not as well supported as the connectivity-based model. Intriguingly, the temporal sequencing of affected regions predicted by the model was in close agreement with Braak stages III-VI, providing what we consider a "computational Braak" staging system. Finally, we investigated whether the regional expression patterns of implicated genes contribute to regional atrophy. Despite robust evidence for genetic factors in PD pathogenesis, NDM outperformed regional genetic expression predictors, suggesting that network processes are far stronger mediators of regional vulnerability than innate or cell-autonomous factors. This is the first finding yet of the ramification of prion-like pathology propagation in Parkinson's, as gleaned from in vivo human imaging data. The NDM is potentially a promising robust and clinically useful tool for diagnosis, prognosis and staging of PD.

Learning from UJAMBO: Perspectives on Gynecologic Care in African Immigrant and Refugee Women in Boston, Massachusetts

African-born immigrant women, and particularly refugees and asylum seekers, are at risk for reproductive health disparities but inadequately use relevant gynecologic services. We sought to elucidate perspectives on gynecologic care in a population of Congolese and Somali immigrants. We conducted a secondary qualitative analysis of focus group data using a grounded theory approach and the Integrated Behavioral Model as our theoretical framework. Thirty one women participated in six focus groups. Participant beliefs included the states of pregnancy and/or pain as triggers for care, preferences included having female providers and those with familiarity with female genital cutting. Barriers included stigma, lack of partner support, and lack of resources to access care. Experiential attitudes, normative beliefs, and environmental constraints significantly mediated care preferences for/barriers to gynecologic health service utilization in this population. Centering of patient perspectives to adapt delivery of gynecologic care to immigrants and refugees may improve utilization and reduce disparities.

Weak correlation of bleeding scores to platelet electron microscopy: A retrospective chart review of pediatric patients with delta-storage pool disorder

BACKGROUND

Delta granule storage pool deficiency (δ-SPD) is a rare platelet disorder in which a deficiency of platelet granules leads to poor aggregation, resulting in varying clinical bleeding phenotypes. Children with δ-SPD have variable laboratory results, making the proper diagnosis and evaluation controversial.

OBJECTIVES

To describe the demographic and laboratory trends of this population and to assess the value of electron microscopy in diagnostic evaluation and its correlation to bleeding symptoms.

METHODS

We performed a retrospective review of 109 pediatric patients diagnosed with δ-SPD. We collected demographic information and bleeding scores using a validated bleeding assessment tool. A descriptive and exploratory analysis was performed.

RESULTS

The majority of patients were female, with an average age at diagnosis of 11.61 years. Females were diagnosed at a significantly older age presenting most often with menorrhagia, while males presented most commonly with epistaxis. The majority showed normal lumiaggregometry, the mean platelet electron microscopy (PEM) value was 2.37, and the mean bleeding score was 6. Bleeding assessment tool and PEM had a significantly weak correlation.

CONCLUSIONS

Patients with more dense granules per platelet had higher bleeding scores than those with fewer dense granules per platelet. The current body of evidence does not favor the use of PEM in routine clinical practice, and results are difficult to interpret. In patients with severe mucocutaneous bleeding symptoms and normal platelet aggregation studies, consideration should be given to an alternative diagnosis and further evaluation is warranted.

Non-inertial lift induced migration for label-free sorting of cells in a co-flowing aqueous two-phase system

We present a novel label-free passive microfluidic technique for isolation of cancer cells (EpCAM+ and CD45−) from peripheral blood mononuclear cells (PBMCs) (CD45+ and EpCAM−) in aqueous two-phase system (ATPS).

Acute effect of primary PCI on diastolic dysfunction recovery in anterior wall STEMI - A non-invasive evaluation by echocardiography

BACKGROUND

It is well established fact that acute coronary occlusion leads to diastolic dysfunction, followed by systolic dysfunction when myonecrosis occur. It is also proven that primary percutaneous coronary intervention (PPCI) is an excellent therapy for ST elevation myocardial infarction (STEMI) to improve outcomes. However there is a paucity of information on efficacy of PPCI in improving diastolic function. Evaluation of the role of PPCI in improving diastolic dysfunction is required.

METHODS

61 patients with first anterior wall STEMI who underwent PPCI to left anterior descending artery were included. Echocardiographic evaluation was performed within 24 h of PPCI and then on day 15, 3 months and 6 months after PPCI. We evaluated the prevalence of diastolic dysfunction after PPCI and its recovery during 6 months along with effect of duration of chest pain on diastolic function.

RESULTS

54.1% of patients had diastolic dysfunction after PPCI whereas it was only 21.3% after 6 months (p value < 0.001). Diastolic function indices like deceleration time, isovolumic relaxation time, E wave, A wave, E/A ratio, left atrial volume and index improved statistically from baseline to 6 months except mitral E/e' ratio. As time required to achieve reperfusion increases (chest pain duration and D to B time) the incidence of residual diastolic dysfunction also increases (p value < 0.001). Patients with TIMI flow < III had more diastolic dysfunction (p value < 0.001).

CONCLUSIONS

Primary PCI improves diastolic dysfunction in patients with anterior wall STEMI over a period of 6 months. Time to achieve reperfusion and effectiveness of reperfusion have significant effect on diastolic dysfunction.

Entry and passage behavior of biological cells in a constricted compliant microchannel

We report an experimental and theoretical investigation of the entry and passage behaviour of biological cells (HeLa and MDA-MB-231) in a constricted compliant microchannel. Entry of a cell into a micro-constriction takes place in three successive regimes: protrusion and contact (cell protrudes its leading edge and makes a contact with the channel wall), squeeze (cell deforms to enter into the constriction) and release (cell starts moving forward). While the protrusion and contact regime is insensitive to the flexibility of the channel, the squeeze zone is significantly smaller in the case of a more compliant channel. Similarly, in the release zone, the acceleration of the cells into the microconstriction is higher in the case of a more compliant channel. The results showed that for a fixed size ratio ρ and E c, the extension ratio λ decreases and transit velocity U c increases with increase in the compliance parameter f p. The variation in the cell velocity is governed by force due to the cell stiffness F s as well as that due to the viscous dampening F d, explained using the Kelvin-Voigt viscoelastic model. The entry time t e = m(ρ) k 1 (1 + f p) k 2 (E c) k 3 and induced hydrodynamic resistance of a cell ΔR c/R = k(ρ) a (1 + k f f p) b (k E E c) c were correlated with cell size ratio ρ, Young's modulus E c and compliance parameter f p, which showed that both entry time t e and the induced hydrodynamic resistance ΔR c are most sensitive to the change in the compliance parameter f p. This study provides understanding of the passage of cells in compliant micro-confinements that can have significant impact on mechanophenotyping of single cells.

A slow-cycling subpopulation of melanoma cells with highly invasive properties

Melanoma is a heterogeneous tumor with different subpopulations showing different proliferation rates. Slow-cycling cells were previously identified in melanoma, but not fully biologically characterized. Using the label-retention method, we identified a subpopulation of slow-cycling cells, defined as label-retaining cells (LRC), with strong invasive properties. We demonstrate through live imaging that LRC are leaving the primary tumor mass at a very early stage and disseminate to peripheral organs. Through global proteome analyses, we identified the secreted protein SerpinE2/protease nexin-1 as causative for the highly invasive potential of LRC in melanomas.

A combined experimental and theoretical approach towards mechanophenotyping of biological cells using a constricted microchannel

We report a combined experimental and theoretical technique that enables the characterization of various mechanical properties of biological cells. The cells were infused into a microfluidic device that comprises multiple parallel micro-constrictions to eliminate device clogging and facilitate characterization of cells of different sizes and types on a single device. The extension ratio λ and transit velocity U_c of the cells were measured using high-speed and high-resolution imaging which were then used in a theoretical model to predict the Young's modulus E_c = f(λ, U_c) of the cells. The predicted Young's modulus E_c values for three different cell lines (182 ± 34.74 Pa for MDA MB 231, 360 ± 75 Pa for MCF 10A and, 763 ± 93 Pa for HeLa) compare well with those reported in the literature from micropipette measurements and atomic force microscopy measurement within 10% and 15%, respectively. Also, the Young's modulus of MDA-MB-231 cells treated with 50 μM 4-hyrdroxyacetophenone (for localization of myosin II) for 30 min was found out to be 260 ± 52 Pa. The entry time t_e of cells into the micro-constrictions was predicted using the model and validated using experimentally measured data. The entry and transit behaviors of cells in the micro-constriction including cell deformation (extension ratio λ) and velocity U_c were experimentally measured and used to predict various cell properties such as the Young's modulus, cytoplasmic viscosity and induced hydrodynamic resistance of different types of cells. The proposed combined experimental and theoretical approach leads to a new paradigm for mechanophenotyping of biological cells.

Iatrogenic left main coronary artery dissection due to pin-hole balloon rupture: Not to be panicked…

Iatrogenic left main coronary artery (LMCA) dissection is a rare complication and may have devastating consequences if not immediately intervened. The management includes urgent revascularization mostly with percutaneous coronary intervention (PCI) with bail-out stenting and rarely requires coronary artery bypass graft (CABG) surgery. In clinically and hemodynamically stable patients, a conservative approach may be preferred. Here, we present a rare case of iatrogenic retrograde LMCA dissection due to pin-hole rupture of angioplasty balloon that was managed conservatively.

Characterization and sorting of cells based on stiffness contrast in a microfluidic channel

This paper reports the characterization and sorting of cells based on stiffness contrast. A microfluidic device with focusing and spacing control for stiffness based sorting of cells is designed, fabricated and demonstrated.

Assessment of knowledge of medicinal plants and their use in tribal region of Jashpur district of Chhattisgarh, India

The present study was conducted to assess the knowledge of medicinal plants and their use in tribal region of Jashpur district of Chhattisgarh. Under the socio-economic profile, farmers of middle age (36-55 yrs) people showed the maximum percentage (78%) distribution and frequency, 50 per cent of respondents belonged to primary to middle school level of education and 63 per cent of respondents were having medium size of family (5 to 8 members). A total number of 50 medicinal plant species belonging to 29 families were recorded, in which Euphorbiaceae registered as the largest family with 4 plant species (8%). Shrub showed their maximum presence (34%) followed by tree (32%), herb (20%) and climber (14%). As per knowledge of respondents about medicinal plants Haldi and Bhui-neem is mostly use as medicinal purpose as 5.2% (n=40) followed by Harra, Munga, Karanj and Hadjod (3.9% each). This information through respondent (tribals) showed very diverse nature of medicinal flora, their usage in healing purpose with socioeconomic/ living standard upliftment. Therefore, it is needful aspect of conserving these biological resources for sustainable ecosystem.

Modeling the relationship among gray matter atrophy, abnormalities in connecting white matter, and cognitive performance in early multiple sclerosis

BACKGROUND AND PURPOSE

Quantitative assessment of clinical and pathologic consequences of white matter abnormalities in multiple sclerosis is critical in understanding the pathways of disease. This study aimed to test whether gray matter atrophy was related to abnormalities in connecting white matter and to identify patterns of imaging biomarker abnormalities that were related to patient processing speed.

MATERIALS AND METHODS

Image data and Symbol Digit Modalities Test scores were collected from a cohort of patients with early multiple sclerosis. The Network Modification Tool was used to estimate connectivity irregularities by projecting white matter abnormalities onto connecting gray matter regions. Partial least-squares regression quantified the relationship between imaging biomarkers and processing speed as measured by the Symbol Digit Modalities Test.

RESULTS

Atrophy in deep gray matter structures of the thalami and putamen had moderate and significant correlations with abnormalities in connecting white matter (r = 0.39-0.41, P < .05 corrected). The 2 models of processing speed, 1 for each of the WM imaging biomarkers, had goodness-of-fit (R(2)) values of 0.42 and 0.30. A measure of the impact of white matter lesions on the connectivity of occipital and parietal areas had significant nonzero regression coefficients.

CONCLUSIONS

We concluded that deep gray matter regions may be susceptible to inflammation and/or demyelination in white matter, possibly having a higher sensitivity to remote degeneration, and that lesions affecting visual processing pathways were related to processing speed. The Network Modification Tool may be used to quantify the impact of early white matter abnormalities on both connecting gray matter structures and processing speed.

Factors associated with study attrition among HIV-infected risky drinkers in St. Petersburg, Russia

BACKGROUND

Participant attrition in HIV longitudinal studies may introduce bias and diminish research quality. The identification of participant characteristics that are predictive of attrition might inform retention strategies.

OBJECTIVE

The study aimed to identify factors associated with attrition among HIV-infected Russian risky drinkers from the secondary HIV prevention HERMITAGE trial. We examined whether current injection drug use (IDU), binge drinking, depressive symptoms, HIV status nondisclosure, stigma, and lifetime history of incarceration were predictors of study attrition. We also explored effect modification due to gender.

METHODS

Complete loss to follow-up (LTFU), defined as no follow-up visits after baseline, was the primary outcome, and time to first missed visit was the secondary outcome. We used multiple logistic regression models for the primary analysis, and Cox proportional hazards models for the secondary analysis.

RESULTS

Of 660 participants, 101 (15.3%) did not return after baseline. No significant associations between independent variables and complete LTFU were observed. Current IDU and HIV status nondisclosure were significantly associated with time to first missed visit (adjusted hazard ratio [AHR], 1.39; 95% CI, 1.03-1.87; AHR, 1.38; 95% CI, 1.03-1.86, respectively). Gender stratified analyses suggested a larger impact of binge drinking among men and history of incarceration among women with time to first missed visit.

CONCLUSIONS

Although no factors were significantly associated with complete LTFU, current IDU and HIV status nondisclosure were significantly associated with time to first missed visit in HIV-infected Russian risky drinkers. An understanding of these predictors may inform retention efforts in longitudinal studies.

Reduced glucose uptake and Aβ in brain regions with hyperintensities in connected white matter

Interstitial concentration of amyloid beta (Aß) is positively related to synaptic activity in animal experiments. In humans, Aß deposition in Alzheimer's disease overlaps with cortical regions highly active earlier in life. White matter lesions (WML) disrupt connections between gray matter (GM) regions which in turn changes their activation patterns. Here, we tested if WML are related to Aß accumulation (measured with PiB-PET) and glucose uptake (measured with FDG-PET) in connected GM. WML masks from 72 cognitively normal (age 61.7 ± 9.6 years, 71% women) individuals were obtained from T2-FLAIR. MRI and PET images were normalized into common space, segmented and parcellated into gray matter (GM) regions. The effects of WML on connected GM regions were assessed using the Change in Connectivity (ChaCo) score. Defined for each GM region, ChaCo is the percentage of WM tracts connecting to that region that pass through the WML mask. The regional relationship between ChaCo, glucose uptake and Aß was explored via linear regression. Subcortical regions of the bilateral caudate, putamen, calcarine, insula, thalamus and anterior cingulum had WM connections with the most lesions, followed by frontal, occipital, temporal, parietal and cerebellar regions. Regional analysis revealed that GM with more lesions in connecting WM and thus impaired connectivity had lower FDG-PET (r = 0.20, p<0.05 corrected) and lower PiB uptake (r = 0.28, p<0.05 corrected). Regional regression also revealed that both ChaCo (β = 0.045) and FDG-PET (β = 0.089) were significant predictors of PiB. In conclusion, brain regions with more lesions in connecting WM had lower glucose metabolism and lower Aß deposition.

Inhibition of intestinal tumor formation by deletion of the DNA methyltransferase 3a

Aberrant de novo methylation of DNA is considered an important mediator of tumorigenesis. To investigate the role of de novo DNA methyltransferase 3a (Dnmt3a) in intestinal tumor development, we analyzed the expression of Dnmt3a in murine colon crypts, murine colon adenomas and human colorectal cancer using RNA fluorescence in situ hybridization (FISH), quantitative PCR and immunostaining. Following conditional deletion of Dnmt3a in the colon of APC((Min/+)) mice, we analyzed tumor numbers, genotype of macroadenomas and laser dissected microadenomas, global and regional DNA methylation and gene expression. Our results showed increased Dnmt3a expression in colon adenomas of APC((Min/+)) mice and human colorectal cancer samples when compared with control tissue. Interestingly, in tumor tissue, RNA FISH analysis showed highest Dnmt3a expression in Lgr5-positive stem/progenitor cells. Deletion of Dnmt3a in APC((Min/+)) mice reduced colon tumor numbers by ~40%. Remaining adenomas and microadenomas almost exclusively contained the non-recombined Dnmt3a allele; no tumors composed of the inactivated Dnmt3a allele were detected. DNA methylation was reduced at the Oct4, Nanog, Tff2 and Cdkn1c promoters and expression of the tumor-suppressor genes Tff2 and Cdkn1c was increased. In conclusion, our results show that Dnmt3a is predominantly expressed in the stem/progenitor cell compartment of tumors and that deletion of Dnmt3a inhibits the earliest stages of intestinal tumor development.

Sexually transmitted infections among HIV-infected heavy drinkers in St Petersburg, Russia

The objective of this study was to estimate the prevalence and identify correlates of four sexually transmitted infections (STIs) among HIV-infected Russians reporting heavy alcohol use and recent unprotected sex, we conducted a cross-sectional analysis of baseline data from the HERMITAGE study. The primary outcome was any current STI, based on urine tests for Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis and serological testing for infection with Treponema pallidum. Data on potential demographic and behavioural predictors of STI were obtained from surveys administered at study entry. Of 682 participants, 12.8% (95% confidence interval [CI] 10.3, 15.3) tested positive for at least one STI. In a multivariable model adjusted for gender, age and marital status, only sex trade involvement over the last three months was significantly associated with an increased odds of STI (adjusted odds ratio [AOR] 2.00, 95% CI 1.13, 3.55). Given that STIs were common in this HIV-infected cohort, and that few patient characteristics predicted STI, the current practice of screening HIV-infected Russians for syphilis alone merits re-evaluation.

D-Dimer assay as a non invasive test for the diagnosis of left atrial Thrombi in Indian patients with Rheumatic MS

BACKGROUND

Systemic embolism is a serious and sometime fatal complication of rheumatic MS.

OBJECTIVE

We assessed the predictive power of D-Dimer level to predict occurrence of left atrial (LA) thrombi in patients with rheumatic mitral stenosis (MS).

METHODS

D-dimer levels were analyzed for 24 patients with rheumatic MS with LA clot and 22 patients with rheumatic MS with no LA clot undergoing transeosophageal echocardiography. A level more than 4 µg/ml was taken as elevated to predict the presence of LA clot in the study groups.

RESULTS

For a cut-off value of 4 µg/ml, sensitivity was 66.67 % and specificity 100 % for prediction of LA clot and AUC 0.710. A cut-off value of less than 1 µg/ml, sensitivity was 91.67 % and 87. 5 % negative predictive value for ruling out presence of LA clot and AUC 0.721.

CONCLUSION

A higher value of D-dimer can predict the possible presence of a LA clot and very low value can predict absence of clot in patients with rheumatic MS.