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There is considerable interest in uncovering the pathway of amybid formation because the toxic properties of amyboid likely stems from prefibril intermediates and not the fully formed fibrils. Using a recently invented method of collecting 2-dimensional infrared spectra and site-specific isotope labeling, we have measured the development of secondary structures for 6 residues during the aggregation process of the 37-residue polypeptide associated with type 2 diabetes, the human islet amyboid polypeptide (hIAPP). By monitoring the kinetics at 6 different labeled sites, we find that the peptides initially develop well-ordered structure in the region of the chain that is close to the ordered loop of the fibrils, followed by formation of the 2 parallel β-sheets with the N-terminal β-sheet likely forming before the C-terminal sheet. This experimental approach provides a detailed view of the aggregation pathway of hIAPP fibril formation as well as a general methodology for studying other amyboid forming proteins without the use of structure-perturbing labels. [ABSTRACT FROM AUTHOR]

The capability of 2D IR spectroscopy to elucidate time-evolving structures is enhanced by a programmable mid-IR pulse shaper that greatly improves the ease, speed, and accuracy of data collection. Traditional ways of collecting 2D IR spectra are difficult to implement, cause distorted peak shapes, and result in poor time resolution and/or phase problems. We report on several methods for collecting 2D IR spectra by using a computer-controlled germanium acoustooptic modulator that overcomes the above problems. The accuracy and resolution of each method is evaluated by using model metal carbonyl compounds that have well defined line-shapes. Furthermore, phase cycling can now be employed to largely alleviate background scatter from heterogeneous samples. With these methods in hand, we apply 2D IR spectroscopy to study the structural diversity in amyloid fibers of aggregated human islet amyloid polypeptide (hIAPP), which is involved with type 2 diabetes. The 2D IR spectra reveal that the β-sheet fibers have a large structural distribution, as evidenced by an inhomogeneously broadened β-sheet peak and strong coupling to random coil conformations. Structural diversity is an important characteristic of hIAPP because it may be that partly folded peptides cause the disease. This experiment on hIAPP is an example of how computer generation of 2D IR pulse sequences is a key step toward automating 2D IR spectroscopy, so that new pulse sequences can be implemented quickly and a diverse range of systems can be studied more easily. [ABSTRACT FROM AUTHOR]

Objective: To clone, express, purify the Per a 4 gene encoding an allergen of Periplaneta Americana and prepare monoclonal antibodies against the recombinant allergen., Methods: The total RNA was extracted from P. Americana , and the target gene was amplified by RT-PCR and cloned into pMD18-T vector. After being confirmed by nucleotide sequencing, the gene was then inserted into pGEX-3X to construct the express vector pGEX-3X-Per a 4. Further, the pGEX-3X-Per a 4 was transformed into E. coli BL21 (DE3), and induced for expression by IPTG. By affinity chromatography, the recombinant allergen was purified and identified by SDS-PAGE and Western blotting. The BALB/c mouse was immunized with the recombinant allergen to prepare the specific monoclonal antibodies, which was then identified by co-immunoprecipitatin and western blotting., Results: The full-length cDNA encoding Per a 4 of P. Americana was obtained with 552 bp in length, which had 99.4% similarity with the reference sequence (GenBank AY792948). The constructed vector pGEX-3X-Per a 4 was transformed in E. coli BL21 (DE3), expressed with the induction of IPTG. By SDS-PAGE, a band of about 49 KD was present. Further, the western-blotting showed that the prepared monoclonal antibodies can bind the serum antibodies in patients allergic to P. Americana ., Conclusions: Both the recombinant allergen Per a 4 and its monoclonal antibodies were obtained., (© 2018 by the Association of Clinical Scientists, Inc.)

Medical images edge detection is an important work for object recognition of the human organs and it is an important pre-processing step in medical image segmentation and 3D reconstruction. Conventionally, edge is detected according to some early brought forward algorithms such as gradient-based algorithm and template-based algorithm, but they are not so good for noise medical image edge detection. In this paper, basic mathematical morphological theory and operations are introduced at first, and then a novel mathematical morphological edge detection algorithm is proposed to detect the edge of lungs CT image with salt-and-pepper noise. The experimental results show that the proposed algorithm is more efficient for medical image denoising and edge detection than the usually used template-based edge detection algorithms and general morphological edge detection algorithms.

A pocket blood sugar apparatus tested by enzyme electrode, which was designed using carbon and silver plasma as conducting materials. Both the work and reference electrodes are applied to the parts of enzyme electrode. The glucose oxidase is taken as the medium of blood sugar measuring. And the range of measuring glucose is about 50mg/dL - 500mgl/dL. It has better linear for the results and fit coefficient arrives at 0.985. Its sensitivity of measurement is higher than current glucose biosensor obviously. A single chip microcomputer, AD mu C812, is used for central control processor of the instrument parts. It measures the output of microampere level currency, which is conduced by blood sugar reacting with the glucose oxidase on the enzyme electrode. And at the same time, the microampere level currency is amplified, processed. Then the results are displayed on LCD. The apparatus are better for measuring blood sugar, and the results are consistent with what the large biochemical instruments get.