Proteomic analysis of human plasma in chronic rheumatic mitral stenosis reveals proteins involved in the complement and coagulation cascade

Background

Rheumatic fever in childhood is the most common cause of Mitral Stenosis in developing countries. The disease is characterized by damaged and deformed mitral valves predisposing them to scarring and narrowing (stenosis) that results in left atrial hypertrophy followed by heart failure. Presently, echocardiography is the main imaging technique used to diagnose Mitral Stenosis. Despite the high prevalence and increased morbidity, no biochemical indicators are available for prediction, diagnosis and management of the disease. Adopting a proteomic approach to study Rheumatic Mitral Stenosis may therefore throw some light in this direction. In our study, we undertook plasma proteomics of human subjects suffering from Rheumatic Mitral Stenosis (n = 6) and Control subjects (n = 6). Six plasma samples, three each from the control and patient groups were pooled and subjected to low abundance protein enrichment. Pooled plasma samples (crude and equalized) were then subjected to in-solution trypsin digestion separately. Digests were analyzed using nano LC-MS^E. Data was acquired with the Protein Lynx Global Server v2.5.2 software and searches made against reviewed Homo sapiens database (UniProtKB) for protein identification. Label-free protein quantification was performed in crude plasma only.

Results

A total of 130 proteins spanning 9–192 kDa were identified. Of these 83 proteins were common to both groups and 34 were differentially regulated. Functional annotation of overlapping and differential proteins revealed that more than 50% proteins are involved in inflammation and immune response. This was corroborated by findings from pathway analysis and histopathological studies on excised tissue sections of stenotic mitral valves. Verification of selected protein candidates by immunotechniques in crude plasma corroborated our findings from label-free protein quantification.

Conclusions

We propose that this protein profile of blood plasma, or any of the individual proteins, could serve as a focal point for future mechanistic studies on Mitral Stenosis. In addition, some of the proteins associated with this disorder may be candidate biomarkers for disease diagnosis and prognosis. Our findings might help to enrich existing knowledge on the molecular mechanisms involved in Mitral Stenosis and improve the current diagnostic tools in the long run.

Electronic supplementary material

The online version of this article (doi:10.1186/1559-0275-11-35) contains supplementary material, which is available to authorized users.     

Platypnoea-orthodeoxia syndrome,an underdiagnosed cause of hypoxaemia: four cases and the possible underlying mechanisms

Cardiac platypnoea-orthodeoxia syndrome (POS) is a position-dependent condition of dyspnoea and hypoxaemia due to right-to-left shunting. It often remains unrecognised in clinical practice, possibly because of its complex underlying pathophysiology. We present four consecutive patients with POS and patent foramen ovale (PFO) who underwent a successful percutaneous PFO closure, describe the mechanism of their POS and provide a review of the literature.     

Whole saliva and the diagnosis of Sjögren's syndrome: an evaluation of patients who complain of dry mouth and dry eyes. Part 1: Screening tests

Sjögren's Syndrome (SS) is a common autoimmune disorder characterised by generalised desiccation, exocrine hypofunction and serologic abnormalities, More than 90% of the patients are women. Objective : to determine if whole saliva could be used to diagnose this disease. Setting: The study was conducted at the School of Dental Medicine, SUNY, at Stony Brook. Patients : There were 49 subjects (48F; 1M), the mean age was 54 ± 13 years. In order to be admitted into the study, they had to complain of dry mouth and dry eyes. Tests : Whole saliva was collected by the spitting method. “Screening Tests'” were employed to measure the salivary flow rate, pH, buffer capacity; lactobacillus and yeast concentrations. Chemical tests were performed to determine protein, albumin, sodium and amylase activity. Lacrimal dryness was assessed by the Schirmer and Rose-Bengal methods. Results: Based on the sialometric findings, the patients were divided into 3 groups: Group 1: those with abnormally low resting (RFR) and stimulated (SFR) flow rates; Group 2: those with a low RFR but normal SFR; and Group 3: those with normal salivary flow rates. The group 1 patients were unique: their saliva demonstrated a low pH and buffer capacity, high lactobacillus and yeast concentrations, decreased protein output and amylase activity, and elevated albumin and sodium. Moreover, virtually all of them had abnormally low lacrimal flow rates. Conclusions : The findings suggested that whole saliva could be used to provisionally diagnose SS. Critical to this diagnosis was an abnormally low stimulated whole saliva flow rate. Other requisites included a low resting flow rate, the presence of dry mouth and dry eyes and evidence of lacrimal hypofunction. All of these attributes can easily be obtained by dentists in their clinics.     

A test for constant fatality rate of an emerging epidemic: with applications to severe acute respiratory syndrome in Hong Kong and Beijing

Summary .   The etiology, pathogenesis, and prognosis for a newly emerging disease are generally unknown to clinicians. Effective interventions and treatments at the earliest possible times are warranted to suppress the fatality of the disease to a minimum, and inappropriate treatments should be abolished. In this situation, the ability to extract most information out of the data available is critical so that important decisions can be made. Ineffectiveness of the treatment can be reflected by a constant fatality over time while effective treatment normally leads to a decreasing fatality rate. A statistical test for constant fatality over time is proposed in this article. The proposed statistic is shown to converge to a Brownian motion asymptotically under the null hypothesis. With the special features of the Brownian motion, we are able to analyze the first passage time distribution based on a sequential tests approach. This allows the null hypothesis of constant fatality rate to be rejected at the earliest possible time when adequate statistical evidence accumulates. Simulation studies show that the performance of the proposed test is good and it is extremely sensitive in picking up decreasing fatality rate. The proposed test is applied to the severe acute respiratory syndrome data in Hong Kong and Beijing.     

Fine‐scale refuges can buffer demographic and genetic processes against short‐term climatic variation and disturbance: a 22‐year case study of an arboreal marsupial

Ecological disturbance and climate are key drivers of temporal dynamics in the demography and genetic diversity of natural populations. Microscale refuges are known to buffer species’ persistence against environmental change, but the effects of such refuges on demographic and genetic patterns in response to short‐term environmental variation are poorly understood. We quantified demographic and genetic responses of mountain brushtail possums (Trichosurus cunninghami) to rainfall variability (1992–2013) and to a major wildfire. We hypothesized that there would be underlying differences in demographic and genetic processes between an unburnt mesic refuge and a topographically exposed zone that was burnt in 2009. Fire caused a 2‐year decrease in survival in the burnt zone, but the population grew after the fire due to immigration, leading to increased expected heterozygosity. We documented a fire‐related behavioural shift, where the rate of movement by individuals in the unburnt refuge to the burnt zone decreased after fire. Irrespective of the fire, there were long‐term differences in demographic and genetic parameters between the mesic/unburnt refuge and the nonmesic/burnt zone. Survival was high and unaffected by rainfall in the refuge, but lower and rainfall‐dependent in the nonmesic zone. Net movement of individuals was directional, from the mesic refuge to the nonmesic zone, suggesting fine‐scale source–sink dynamics. There were higher expected heterozygosity (H_E) and temporal genetic stability in the refuge, but lower H_E and marked temporal genetic structure in the exposed habitat, consistent with reduced generational overlap caused by elevated mortality and immigration. Thus, fine‐scale refuges can mediate the short‐term demographic and genetic effects of climate and ecological disturbance.     

Discovery of N-(benzo[1,2,3]triazol-1-yl)-N-(benzyl)acetamido)phenyl) carboxamides as severe acute respiratory syndrome coronavirus (SARS-CoV) 3CLpro inhibitors: Identification of ML300 and noncovalent nanomolar inhibitors with an induced-fit binding

Herein we report the discovery and SAR of a novel series of SARS-CoV 3CLpro inhibitors identified through the NIH Molecular Libraries Probe Production Centers Network (MLPCN). In addition to ML188, ML300 represents the second probe declared for 3CLpro from this collaborative effort. The X-ray structure of SARS-CoV 3CLpro bound with a ML300 analog highlights a unique induced-fit reorganization of the S₂–S₄ binding pockets leading to the first sub-micromolar noncovalent 3CLpro inhibitors retaining a single amide bond.