Divergent barotropic instability of the tropical asymmetric easterly jet

The divergent barotropic instability of a zonally averaged, observed, tropical, upper tropospheric, monsoon easterly jet is investigated by numerical integration of a linear spectral model. The Rossby radius of deformation for the upper troposphere is computed from a three-layer model of the atmosphere. It is shown that the antisymmetric zonal flow components in the jet contribute in stabilizing the short waves and destabilizing the long waves. Furthermore, the maximum amplitude of the asymmetric preferred wave is shifted southward (to 6°N) to a region where a largest positive maximum of −ūvv is located for the asymmetric profile. A large decrease in the meridional scale of the wave and a threefold increase in the ratio of the computed maximum southward-to-northward easterly momentum transports is also found for the asymmetric jet compared to the symmetric jet. The divergence is found to increase the growth rates of all the waves and, also to increase the preferred wavelength. The most unstable divergent asymmetric wave is shown to have a wavelength of 6500 km, an e-folding time of 6.5 days and a westward phase speed of 23.5 m s−1. The zonal scale of the preferred wave is nearly equal to the Rossby radius of deformation

Primary central nervous system lymphomas: Indian experience, and review of literature

Primary central nervous system lymphomas (PCNSLs) are a rare form of non-Hodgkin\u2032s lymphoma which arise within and remain confined primarily to the central nervous system (CNS). They generally account for 1-2% of all primary brain tumors and are reported to be on the rise due to the Acquired Immune Deficiency Syndrome (AIDS) epidemic. Aims and Objectives: To study the clinicopathological and immunophenotypic characteristics of PCNSLs and look for any differences in PCNSLs reported in India from those in other countries. Materials and Methods : All cases of PCNSLs between January 1998 and December 2006 were reviewed. Presence of lymphadenopathy, organomegaly and bone marrow study was done to exclude the possibility of secondary involvement by lymphoma. The diagnosis was confirmed by histopathology with Hematoxylin and Eosin and reticulin stains. Immunohistochemistry (IHC) with leucocyte common antigen (LCA), CD 20 and CD 3 was performed on available blocks. The immune status was evaluated by clinical examination and human immunodeficiency virus (HIV) serology (since 1996). Results : In a 19-year study period, there were 56 patients of PCNSLs, accounting for 1.07% of all intracranial neoplasms. The patients ranged from 10-75 years of age with a median age of 42 years. Barring one patient who was HIV positive, all the others were immunocompetent. All cases were diffuse large cell lymphomas on histopathology. IHC with LCA and CD 20 revealed positivity in 100% and 86.4% cases respectively. There was a single case of CD 3 positive T-cell lymphoma. In the present study, PCNSLs occurred in young immunocompetent patients and majority were diffuse large B cell lymphomas

Primary central nervous system lymphomas: Indian experience, and review of literature

Primary central nervous system lymphomas (PCNSLs) are a rare form of non-Hodgkin\u2032s lymphoma which arise within and remain confined primarily to the central nervous system (CNS). They generally account for 1-2% of all primary brain tumors and are reported to be on the rise due to the Acquired Immune Deficiency Syndrome (AIDS) epidemic. Aims and Objectives: To study the clinicopathological and immunophenotypic characteristics of PCNSLs and look for any differences in PCNSLs reported in India from those in other countries. Materials and Methods : All cases of PCNSLs between January 1998 and December 2006 were reviewed. Presence of lymphadenopathy, organomegaly and bone marrow study was done to exclude the possibility of secondary involvement by lymphoma. The diagnosis was confirmed by histopathology with Hematoxylin and Eosin and reticulin stains. Immunohistochemistry (IHC) with leucocyte common antigen (LCA), CD 20 and CD 3 was performed on available blocks. The immune status was evaluated by clinical examination and human immunodeficiency virus (HIV) serology (since 1996). Results : In a 19-year study period, there were 56 patients of PCNSLs, accounting for 1.07% of all intracranial neoplasms. The patients ranged from 10-75 years of age with a median age of 42 years. Barring one patient who was HIV positive, all the others were immunocompetent. All cases were diffuse large cell lymphomas on histopathology. IHC with LCA and CD 20 revealed positivity in 100% and 86.4% cases respectively. There was a single case of CD 3 positive T-cell lymphoma. In the present study, PCNSLs occurred in young immunocompetent patients and majority were diffuse large B cell lymphomas

CARRS Surveillance study: design and methods to assess burdens from multiple perspectives

Background Cardio-metabolic diseases (CMDs) are a growing public health problem, but data on incidence, trends, and costs in developing countries is scarce. Comprehensive and standardised surveillance for non-communicable diseases was recommended at the United Nations High-level meeting in 2011. Aims: To develop a model surveillance system for CMDs and risk factors that could be adopted for continued assessment of burdens from multiple perspectives in South-Asian countries. Methods Design: Hybrid model with two cross-sectional serial surveys three years apart to monitor trend, with a three-year prospective follow-up of the first cohort. Sites: Three urban settings (Chennai and New Delhi in India; Karachi in Pakistan), 4000 participants in each site stratified by gender and age. Sampling methodology: Multi-stage cluster random sampling; followed by within-household participant selection through a combination of Health Information National Trends Study (HINTS) and Kish methods. Culturally-appropriate and methodologically-relevant data collection instruments were developed to gather information on CMDs and their risk factors; quality of life, health-care utilisation and costs, along with objective measures of anthropometric, clinical and biochemical parameters. The cohort follow-up is designed as a pilot study to understand the feasibility of estimating incidence of risk factors, disease events, morbidity, and mortality. Results The overall participant response rate in the first cross-sectional survey was 94.1% (Chennai 92.4%, n = 4943; Delhi 95.7%, n = 4425; Karachi 94.3%, n = 4016). 51.8% of the participants were females, 61.6% \u3c 45years, 27.5% 45–60years and 10.9% \u3e60 years. Discussion This surveillance model will generate data on prevalence and trends; help study the complex life-course patterns of CMDs, and provide a platform for developing and testing interventions and tools for prevention and control of CMDs in South-Asia. It will also help understanding the challenges and opportunities in establishing a surveillance system across countries

Awareness regarding eye donation among stakeholders in Srikakulam district in South India

Background There is a huge need for the availability of transplantable donor corneas worldwide to reduce the burden of corneal blindness due to corneal opacity. Voluntary eye donation depends on the awareness levels of various stakeholders in the community. This study aimed to assess the awareness level regarding eye donation among various stakeholders in Srikakulam district in the state of Andhra Pradesh, India. Methods 355 subjects were selected from the district using multi stage random sampling. A pre tested semi structured questionnaire was used to collect information regarding each individual’s awareness, knowledge, and perception regarding eye donation. Each response was scored individually and a total score was calculated. Univariate and multivariate regression analysis was used to determine the factors associated with willingness towards eye donation and increased awareness levels. Results Of the 355 subjects interviewed, 192 (54%) were male and 163 (46%) were female. The mean age of the stakeholders was 35.9 years (SD ±16.1) and all the study subjects were literate. Ninety-three percent of subjects were aware of the concept of eye donation. Knowledge levels were similar among the teaching community and persons engaged in social service, but lower among students (p < 0.05). Among the stakeholders, there was considerable ambiguity regarding whether persons currently wearing spectacles or suffering from a chronic illnesses could donate their eyes. Older age group (p < 0.001), female gender (p < 0.001) and education (p < 0.001) were associated with increased knowledge levels. 82% of the subjects were willing to donate their eyes and this was unaffected by gender or geographical location (rural vs urban). Conclusions Awareness levels and willingness to donate eyes are high among the stakeholders in Srikakulam district in India. The services of stakeholders could be utilized, in conjunction with other community based eye donation counselors, to promote awareness regarding eye donation among the general population

Emerging pharmacotherapy of tinnitus

Tinnitus, the perception of sound in the absence of an auditory stimulus, is perceived by about 1 in 10 adults, and for at least 1 in 100, tinnitus severely affects their quality of life. Because tinnitus is frequently associated with irritability, agitation, stress, insomnia, anxiety and depression, the social and economic burdens of tinnitus can be enormous. No curative treatments are available. However, tinnitus symptoms can be alleviated to some extent. The most widespread management therapies consist of auditory stimulation and cognitive behavioral treatment, aiming at improving habituation and coping strategies. Available clinical trials vary in methodological rigor and have been performed for a considerable number of different drugs. None of the investigated drugs have demonstrated providing replicable long-term reduction of tinnitus impact in the majority of patients in excess of placebo effects. Accordingly, there are no FDA or European Medicines Agency approved drugs for the treatment of tinnitus. However, in spite of the lack of evidence, a large variety of different compounds are prescribed off-label. Therefore, more effective pharmacotherapies for this huge and still growing market are desperately needed and even a drug that produces only a small but significant effect would have an enormous therapeutic impact. This review describes current and emerging pharmacotherapies with current difficulties and limitations. In addition, it provides an estimate of the tinnitus market. Finally, it describes recent advances in the tinnitus field which may help overcome obstacles faced in the pharmacological treatment of tinnitus. These include incomplete knowledge of tinnitus pathophysiology, lack of well-established animal models, heterogeneity of different forms of tinnitus, difficulties in tinnitus assessment and outcome measurement and variability in clinical trial methodology. © 2009 Informa UK Ltd.Fil: Langguth, Berthold. Universitat Regensburg; AlemaniaFil: Salvi, Richard. State University of New York; Estados UnidosFil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Admixture Mapping Scans Identify a Locus Affecting Retinal Vascular Caliber in Hypertensive African Americans: the Atherosclerosis Risk in Communities (ARIC) Study

Retinal vascular caliber provides information about the structure and health of the microvascular system and is associated with cardiovascular and cerebrovascular diseases. Compared to European Americans, African Americans tend to have wider retinal arteriolar and venular caliber, even after controlling for cardiovascular risk factors. This has suggested the hypothesis that differences in genetic background may contribute to racial/ethnic differences in retinal vascular caliber. Using 1,365 ancestry-informative SNPs, we estimated the percentage of African ancestry (PAA) and conducted genome-wide admixture mapping scans in 1,737 African Americans from the Atherosclerosis Risk in Communities (ARIC) study. Central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) representing summary measures of retinal arteriolar and venular caliber, respectively, were measured from retinal photographs. PAA was significantly correlated with CRVE (ρ = 0.071, P = 0.003), but not CRAE (ρ = 0.032, P = 0.182). Using admixture mapping, we did not detect significant admixture association with either CRAE (genome-wide score = −0.73) or CRVE (genome-wide score = −0.69). An a priori subgroup analysis among hypertensive individuals detected a genome-wide significant association of CRVE with greater African ancestry at chromosome 6p21.1 (genome-wide score = 2.31, locus-specific LOD = 5.47). Each additional copy of an African ancestral allele at the 6p21.1 peak was associated with an average increase in CRVE of 6.14 µm in the hypertensives, but had no significant effects in the non-hypertensives (P for heterogeneity <0.001). Further mapping in the 6p21.1 region may uncover novel genetic variants affecting retinal vascular caliber and further insights into the interaction between genetic effects of the microvascular system and hypertension

Development of a blood-based molecular biomarker test for identification of schizophrenia before disease onset

Recent research efforts have progressively shifted towards preventative psychiatry and prognostic identification of individuals before disease onset. We describe the development of a serum biomarker test for the identification of individuals at risk of developing schizophrenia based on multiplex immunoassay profiling analysis of 957 serum samples. First, we conducted a meta-analysis of five independent cohorts of 127 first-onset drug-naive schizophrenia patients and 204 controls. Using least absolute shrinkage and selection operator regression, we identified an optimal panel of 26 biomarkers that best discriminated patients and controls. Next, we successfully validated this biomarker panel using two independent validation cohorts of 93 patients and 88 controls, which yielded an area under the curve (AUC) of 0.97 (0.95-1.00) for schizophrenia detection. Finally, we tested its predictive performance for identifying patients before onset of psychosis using two cohorts of 445 pre-onset or at-risk individuals. The predictive performance achieved by the panel was excellent for identifying USA military personnel (AUC: 0.90 (0.86-0.95)) and help-seeking prodromal individuals (AUC: 0.82 (0.71-0.93)) who developed schizophrenia up to 2 years after baseline sampling. The performance increased further using the latter cohort following the incorporation of CAARMS (Comprehensive Assessment of At-Risk Mental State) positive subscale symptom scores into the model (AUC: 0.90 (0.82-0.98)). The current findings may represent the first successful step towards a test that could address the clinical need for early intervention in psychiatry. Further developments of a combined molecular/symptom-based test will aid clinicians in the identification of vulnerable patients early in the disease process, allowing more effective therapeutic intervention before overt disease onset