PEG介导的原生质体融合方法的改进及注意事项

结合科研工作对《细胞工程》教材中PEG介导的原生质体融合方法进行了改进,并对实验过程中注意事项进行了阐述。     

Biomarker discovery for arsenic exposure using functional data. Analysis and feature learning of mass spectrometry proteomic data

Plasma biomarkers of exposure to environmental contaminants play an important role in early detection of disease. The emerging field of proteomics presents an attractive opportunity for candidate biomarker discovery, as it simultaneously measures and analyzes a large number of proteins. This article presents a case study for measuring arsenic concentrations in a population residing in an As-endemic region of Bangladesh using plasma protein expressions measured by SELDI-TOF mass spectrometry. We analyze the data using a unified statistical method based on functional learning to preprocess mass spectra and extract mass spectrometry (MS) features and to associate the selected MS features with arsenic exposure measurements. The task is challenging due to several factors, the high dimensionality of mass spectrometry data, complicated error structures, and a multiple comparison problem. We use nonparametric functional regression techniques for MS modeling, peak detection based on the significant zero-downcrossing method, and peak alignment using a warping algorithm. Our results show significant associations of arsenic exposure to either under- or overexpressions of 20 proteins.     

First homo-peptides undergoing a reversible 3(10)-helix/alpha-helix transition: critical main-chain length

The difference in length between the more elongated peptide 3(10)-helix and the more compact alpha-helix is about 0.4 A/residue. This property makes the 3(10)-/alpha-helix reversible conversion very promising as a molecular switching tool between the N- and C-terminal functions of a peptide backbone. In this work, using homo-peptides of various main-chain length, all based on the strongly helicogenic, Calpha-tetrasubstituted alpha-amino acid Calpha-methyl-L-valine, we show that a well defined, solvent controlled, reversible 3(10)-/alpha-helix transition takes place even in a homo-oligomer as short as a terminally blocked hexapeptide. Homo-peptide sequences blocked as a urethane or an acetamide at the N-terminus and as a methyl ester or an N-alkyl amide at the C-terminus are all appropriate. The nature of the occurring helical species in the various solvents tested was assessed by electronic or vibrational circular dichroism.     

Aggravated Cardiac Remodeling post Aortocaval Fistula in Unilateral Nephrectomized Rats

Background

Aortocaval fistula (AV) in rat is a unique model of volume-overload congestive heart failure and cardiac hypertrophy. Living donor kidney transplantation is regarded as beneficial to allograft recipients and not particularly detrimental to the donors. Impact of AV on animals with mild renal dysfunction is not fully understood. In this study, we explored the effects of AV in unilateral nephrectomized (UNX) rats.

Methods

Adult male Sprague-Dawley (SD) rats were divided into Sham (n = 10), UNX (right kidney remove, n = 10), AV (AV established between the levels of renal arteries and iliac bifurcation, n = 18) and UNX+AV (AV at one week after UNX, n = 22), respectively. Renal outcome was measured by glomerular filtration rate, effective renal plasma flow, fractional excretion of sodium, albuminuria, plasma creatinine, and cystatin C. Focal glomerulosclerosis (FGS) incidence was evaluated by renal histology. Cardiac function was measured by echocardiography and hemodynamic measurements.

Results

UNX alone induced compensatory left kidney enlargement, increased plasma creatinine and cystatin C levels, and slightly reduced glomerular filtration rate and increased FGS. AV induced significant cardiac enlargement and hypertrophy and reduced cardiac function and increased FGS, these changes were aggravated in UNX+AV rats.

Conclusions

Although UNX only induces minor renal dysfunction, additional chronic volume overload placement during the adaptation phase of the remaining kidney is associated with aggravated cardiac dysfunction and remodeling in UNX rats, suggesting special medical care is required for UNX or congenital monokidney subjects in case of chronic volume overload as in the case of pregnancy and hyperthyroidism to prevent further adverse cardiorenal events in these individuals.     

Prediction of Severe Acute Pancreatitis Using a Decision Tree Model Based on the Revised Atlanta Classification of Acute Pancreatitis

Objective

To develop a model for the early prediction of severe acute pancreatitis based on the revised Atlanta classification of acute pancreatitis.

Methods

Clinical data of 1308 patients with acute pancreatitis (AP) were included in the retrospective study. A total of 603 patients who were admitted to the hospital within 36 hours of the onset of the disease were included at last according to the inclusion criteria. The clinical data were collected within 12 hours after admission. All the patients were classified as having mild acute pancreatitis (MAP), moderately severe acute pancreatitis (MSAP) and severe acute pancreatitis (SAP) based on the revised Atlanta classification of acute pancreatitis. All the 603 patients were randomly divided into training group (402 cases) and test group (201 cases). Univariate and multiple regression analyses were used to identify the independent risk factors for the development of SAP in the training group. Then the prediction model was constructed using the decision tree method, and this model was applied to the test group to evaluate its validity.

Results

The decision tree model was developed using creatinine, lactate dehydrogenase, and oxygenation index to predict SAP. The diagnostic sensitivity and specificity of SAP in the training group were 80.9% and 90.0%, respectively, and the sensitivity and specificity in the test group were 88.6% and 90.4%, respectively.

Conclusions

The decision tree model based on creatinine, lactate dehydrogenase, and oxygenation index is more likely to predict the occurrence of SAP.     

Blocking TREM-1 signaling prolongs survival of mice with Pseudomonas aeruginosa induced sepsis

TREM-1 is a recently discovered receptor expressed on neutrophils and macrophages. Blocking of TREM-1 signaling improves the survival of mice with bacterial sepsis. However, the precise mechanism by which TREM-1 modulates the inflammatory responses is poorly defined. In this study, we investigated the role of TREM-1 in Pseudomonas aeruginosa-induced peritonitis. Our results showed that TREM-1 was not expressed on lymphocytes but emerged on the cell surface of neutrophils and peritoneal macrophages. Blockade of TREM-1 signaling significantly prolonged survival of mice with P. aeruginosa-induced peritonitis. However, blocking TREM-1 signaling had no effect on macrophage phagocytosis in vitro. Interestingly, the expression of the costimulatory molecules CD40 and CD86 on macrophages was significantly decreased after blocking TREM-1 signaling. Furthermore, interfering with TREM-1 engagement led to significant reduction of pro-inflammatory mediators such as IL-1, TNF-α, MCP-1 and IFN-γ. Therefore, our results showed that TREM-1 could be a potential therapeutic target for bacterial sepsis.