Diagnostic significance of alanine aminotransferase isoenzymes in alcoholic and non-alcoholic fatty liver cancers.

OBJECTIVES: Alanine aminotransferase (ALT) expression is highly elevated in the serum of patients with hepatocellular carcinoma. However, the role of ALT isoenzymes in the total ALT activity remains unclear. In the present study, we systematically investigated the role of ALT isoenzymes in alcoholic and non-alcoholic fatty liver cancer. MATERIALS AND METHODS: The expression of ALT1 and ALT2 at the mRNA and protein levels in 25 paired primary liver cancer tissues was detected by reverse transcription quantitative PCR (RT-qPCR), Western blotting, and immunohistochemistry. Serum ALT activity was determined using an automated biochemical analyzer. RESULTS: The mRNA and protein expression levels of ALT1 and ALT2 were lower in the tissues of alcoholic and non-alcoholic fatty liver cancers than in the paracancerous tissues. Notably, ALT2 was highly expressed in non-alcoholic fatty liver cancer tissues compared with alcoholic fatty liver cancer tissues. Total serum ALT activity was mainly contributed by ALT1 in alcoholic fatty liver cancer, whereas ALT1 contributed only marginally more to the total ALT activity than ALT2 in non-alcoholic fatty liver cancer. ALT2/ALT1 ratio can well discriminate normal control group, alcoholic liver cancer and non-alcoholic liver cancer. CONCLUSION: ALT1 contributed more to the total ALT activity than ALT2 in both alcoholic and non-alcoholic fatty liver cancer. Serum ALT2 to ALT activity was higher in non-alcoholic fatty liver cancer than that in alcoholic fatty liver cancer. ALT2/ALT1 ratio has some diagnostic significance for alcoholic and non-alcoholic liver cancer.

Monolayered H-Si-P semiconductors: structural stability, electronic structure, optical properties, and prospects for photocatalytic water splitting.

Group IV and V monolayers are promising state-of-the-art two-dimensional (2D) materials owing to their high carrier mobility, tunable bandgaps, and optical linear dichroism along with outstanding electronic and thermoelectric properties. Furthermore, recent studies revealed the stability of free-standing 2D monolayers by hydrogenation. Inspired by this, we systematically predicted and investigated the structure and properties of various hydrogen-saturated silicon phosphide (H-Si-P) monolayers based on first-principles calculations. According to the results, H-Si-P monolayers belong to indirect bandgap semiconductors with a highly stable structure. Their bandgaps and band edge positions assessed using accurate hybrid functional are shown to be effectively adjusted by applying a biaxial strain. Furthermore, the absorption spectra of these monolayers, simulated in the context of time-dependent density functional theory, exhibit their excellent potential for solar energy conversion and visible-light-driven photocatalytic water splitting. In this respect, this work provides valuable guidance for finding more 2D semiconductors and nanostructures for nanoelectronics and optoelectronic applications, as well as for photocatalytic water splitting.

[Study on the distribution of human alanine aminotransferase isoenzyme in human tissues].

This study intends to obtain recombinant proteins of ALT1 and ALT2 isozymes by using genetic recombination technology. Monoclonal antibodies ALT1 and ALT2 with high specificity and high activity were prepared and screened (ALT1 monoclonal antibody has been successfully prepared and published). The localization, distribution and expression of ALT1 and ALT2 isozymes in human tissues were discussed. The ALT2 genes were amplified from human liver cancer cell (HepG2) by RT-PCR method. The mature ALT2 gene was subcloned into the pET32a-ALT2 prokaryotic expression vector. Its ligation product was transformed into BL21(DE3) competent cells, and transformed into competent cells to express ALT2 proteins induced by IPTG. The recombinant proteins of ALT2 were purified by nickel column (Ni⁺) affinity chromatography. Balb/c mice were immunized with recombinant proteins of ALT2. Positive serum mouse spleen cells and myeloma cells SP2/0 were selected for cell fusion. The positive cell lines were selected by indirect ELISA and subcloned by limited dilution method. Affinity chromatography was used to purify ALT2 antibodies. The expression and distribution of ALT2 in human normal tissues were detected by RT-PCR and Western blotting. Results show that the expression of ALT isoenzyme in tissues was almost the same at gene mRNA level and protein level. ALT1 is highly expressed in liver, kidney and skeletal muscle, and moderately expressed in gastrointestinal smooth muscle. ALT2 is highly expressed in fat, skeletal muscle and myocardium, and is poorly expressed in gastrointestinal smooth muscle. Immunohistochemical studies show that ALT1 is highly expressed in hepatocytes, renal medullary tubules and muscle fibers, ALT2 is highly expressed in adipocytes and myocardial cells, and ALT1 and ALT2 in gastrointestinal tissues are mainly expressed in mucosa of upper intestinal wall region. The results showed that the isoenzymes ALT1 and ALT2 were mainly expressed in the mucosa of the upper part of the intestinal wall. It is widely distributed in the tissues, providing theoretical basis for understanding the mechanism of ALT activity increase under different pathological conditions.

Plasmons in N-doped graphene nanostructures tuned by Au/Ag films: a time-dependent density functional theory study.

The energy resonance point of the prominent peak of the absorption spectrum of nitrogen-doped graphene is in the ultraviolet region. This limits its application as a co-catalyst in renewable hydrogen evolution through photocatalytic water splitting in the visible light region. It is well known that noble metal films show active absorption in the visible region due to the existence of the unique feature known as surface plasmon resonance. Here we report tunable plasmons in nitrogen-doped graphene nanostructures using noble metal (Au/Ag) films. The energy resonance point of the prominent peak of the composite nanostructure is altered by changing the separation space of two-layered nanostructures. We found the strength of the absorption spectrum of the composite nanostructure is much stronger than the isolated N-doped graphene monolayer. When the separation space is decreased, the prominent peak of the absorption spectrum is red-shifted to the visible light region. Moreover, currents of several microamperes exist above the surface of the N-doped graphene and Au film composite nanostructure. In addition, the field enhancement exceeds 1000 when an impulse excitation polarized in the armchair-edge direction (X-axis) when the separation space is decreased to 3 Å and is close to 100 when an impulse excitation polarized in the zigzag-edge direction (Y-axis). The N-doped graphene and noble metal film composite nanostructure is a good candidate material as a co-catalyst in renewable hydrogen production by photocatalytic water splitting in the visible light region.