Directional immobilization of antibody onto magnetic nanoparticles by Fc-binding protein-assisted photo-conjugation for high sensitivity detection of antigen.

Immobilized antibodies with site-specific, oriented, and covalent pattern are of great significance to improve the sensitivity of solid-phase immunoassay. Here, we developed a novel antibody conjugation strategy that can immobilize antibodies in a directional and covalent manner. In this study, an IgG-Fc binding protein (Z domain) carrying a site-specific photo-crosslinker, p-benzoyl-L-phenylalanine, and a single C-terminal cysteine (Cys) handle was genetically engineered. Upon UV irradiation, the chimeric protein enables the Cys handle to couple with the native antibody in Fc-specific and covalent conjugation pattern, resulting in a novel thiolated antibody. Thus, an approach for the covalent, directional immobilization of antibodies to maleimide-modified magnetic nanoparticles (MNPs) was developed on the basis of the crosslinking between sulfhydryl and maleimide groups. The antibody-conjugated MNPs were applied in MNP-based enzyme-linked immunosorbent assay (ELISA) for the detection of carcinoembryonic antigen. The MNP-based ELISA presented a quantification linear range of 0.1-100 ng mL-1 and detection limit of 0.02 ng mL-1, which was approximately 100 times more sensitive than the traditional microplate ELISA (2.0 ng mL-1). Thus, the proposed antibody immobilization approach can be used in surface functionalization for the sensitive detection of various biomarkers.

Analysis of the clinical features of recurrent acute pancreatitis in China.

BACKGROUND: Since few systematic studies have focused on recurrent acute pancreatitis in China, we sought to investigate its clinical features, including etiological factors and relative frequency. METHODS: Patients were selected from a total 1471 patients with acute pancreatitis in ten cities of China. All had been admitted to a hospital with an attack of acute pancreatitis between January 1992 and December 2002. Data for each patient was recorded on a standardized form. RESULTS: Of the 1471 patients with acute pancreatitis, 157 (10.7%) had recurrent acute pancreatitis. The majority (63%) were male, with a mean age of 41 years (range, 13-82 years). Regarding the etiology, alcohol (20.4%) and cholelithiasis (20.4%) were the most frequent causes, followed by diet (13.4%), hypertriglyceridemia (8.3%), biliary tract infection (5.7%), other (5.1%), and idiopathic factors (26.8%). Alcohol was most frequent in male patients (30.3%), whereas cholelithiasis was most frequent (34.5%) in female patients. The majority of patients (79.6%) presented with their second attack of pancreatitis. Complications of recurrent acute pancreatitis in order of frequency were pancreatic pseudocyst, multiple organ failure, diabetes mellitus type 2, and shock. CONCLUSIONS: Recurrent acute pancreatitis remains a frequent disease, with cholelithiasis and alcohol being the most usual etiological factors. Alcohol is the primary etiological factor in male patients. In about 26.8% of cases, the etiology remains unknown.

[Observation on the ultrastructure of Pneumocystis carinii].

OBJECTIVE: To study the life cycle and morphology of Pneumocystis carinii by ultrastructural observation. METHODS: Wistar rat model of P. carinii infection was established by subcutaneous injection with dexamethasone. Lung tissue of the infected rats was used for the transmission electron microscopical study. RESULTS: The organisms were mainly present in the lung alveolar cavity, and also in the alveolar septum, pulmonary macrophages and neutrophils. More trophozoites of P. carinii attached to the type I alveolar epithelial cells, and rarely to the type II alveolar epithelial cells. Most of these trophozoites showed pseudopodial evaginations on their pellicles. The nucleus-associated organelle and spindle microtubules were observed in some trophozoites. The precyst phase was in three forms: early, intermediate and late form. Synaptonemal complexes indicating meiotic nuclear divisions and a clump of mitochondria were also observed in the precyst. The pellicle of the cyst has a thickened portion with a pore. There were nucleus with nucleolus, mitochondrion, vesicles, endoplasmic reticulum and numerous ribosomes in the organisms, and tubular expansions on its surface. CONCLUSION: The life cycle of P. carinii consists of trophozoite, precyst and cyst stages. The presence of a single pore in the cyst wall reveals that pore formation may be a mode of excystation for intracystic bodies of P. carinii.

[The clinical features of acute pancreatitis in 10 cities in Shandong Province].

OBJECTIVE: To investigate and obtain a more comprehensive view of the etiology and clinical features of acute pancreatitis (AP) in Shandong Province. METHODS: 1471 cases admitted to hospital for AP were studied and collected from the ten cities of Shandong Province from January 1992 to December 2002 retrospectively. Data of each enrolled patient was recorded in a standardized form. RESULTS: In the 1471 patients, the ratio of male: female was 854:617, and also the mean age of them and the range was 43.3 and from 13 - 82 years old. 1280 had mild AP, and 191 had sever AP. Cholelithiasis (20.2%), alcohol (17.3%) and diet-induced (12.4%) were the most frequent etiologic factors, followed by biliary tract infections (5.6%), hyperlipemia (2.3%), other factors (5.1%). But in about 36.1% cases, the etiology of AP still remains unexplained. In coastal regions, cholelithiasis is the most frequent factor but in interior regions alcohol ranked first. In male, a small predominance of alcohol over cholelithiasis was seen (27.4 vs.14.3%, P < 0.01); and in female, there was a clear predominance of cholelithiasis over alcohol (28.4 vs. 3.2%, P < 0.01). The complications of AP were pancreatic pseudocyst, ascites and peritonitis, pulmonary infections, multiple organ failure, diabetes mellitus-2 and shock, etc. according to their frequencies. CONCLUSIONS: Cholelithiasis, alcohol and diet-induced factor were main etiologic factors in Shandong Province, whereas cholelithiasis alone predominated in the females. In about 36.1% cases, the etiology remains unknown. So that more attention should be paid to study the etiology of AP.

Analysis of clinical features of acute pancreatitis in Shandong Province, China.

AIM: To investigate and obtain a more comprehensive view of the etiology and clinical features of acute pancreatitis in China. METHOD: The study comprised 1471 patients in 10 cites of China who were admitted to hospitals for acute pancreatitis from January 1992 to December 2002. Data for each patient were collected on a standardized form. RESULTS: Of the 1471 patients (854 men, 617 women; mean age 43.3 years; range 13-82 years), 1280 had mild pancreatitis and 191 had the severe form. Cholelithiasis (20.2%), alcohol (17.3%) and diet-induced (12.4%) were the most frequent etiological factors, followed by biliary tract infections (5.6%), hyperlipidemia (2.3%) and other factors (5.1%). However, in about 36.1% of cases, the etiology of acute pancreatitis still remained unexplained. In coastal regions, cholelithiasis was the most frequent factor but alcohol ranked first in interior regions. In males, a small predominance of alcohol over cholelithiasis was seen (27.4%vs 14.3%) and there was a clear predominance of cholelithiasis over alcohol (28.4%vs 3.2%) in females. The differences in the frequency of cholelithiasis and alcohol between coastal regions and interior regions and males and females were statistically significant (P < 0.01). According to their frequency, complications of acute pancreatitis were pancreatic pseudocyst, pancreatic ascites and bacterial peritonitis, pulmonary infections, multiple organ failure, diabetes mellitus type 2 and shock. CONCLUSION: Cholelithiasis, alcohol and diet-induced factors were the main etiological factors seen in China, whereas cholelithiasis alone predominated in females and alcohol ranked first in males. In about 36.1% of cases, the etiology of acute pancreatitis remained unknown. More attention should be paid to studying the etiologies of acute pancreatitis that remain unknown.