dissociation

Background: C-type natriuretic peptide (CNP) was isolated from porcine brain and is a 22-amino acid peptide which belongs to the natriuretic peptide (NP) family. Even though this peptide shares structural similarity to other endogenous NPs including atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) its receptor selectivity is different from other NPs. The present study was undertaken to investigate the expression of C-type natriuretic peptide (CNP) and its specific guanylyl cyclase (GC)-coupled receptor in the granulosa cells of the pig ovarian follicle. Results: Specific 125I-[Tyr0]-CNP(1-22) binding sites were localized in the granulosa cell layer of the ovarian follicle with an apparent dissociation constant (Kd>) and a maximal binding capacity (Bmax) of 1.41±0.39 nM and 2.75±0.65 fmol/mm2 respectively. Binding of 125I-[Tyr0]-CNP(1-22) to these sites was also prevented by atrial natriuretic peptide (ANP(1-28)), brain natriuretic peptide (BNP(1-26)) and des[Gln18,Ser19,Gly20, Leu21,Gly22] ANP(4-23) (C-ANP). Production of 3’,5’-cyclic guanosine monophosphate (cGMP) by particulate GC in the granulosa cell membranes was stimulated by natriuretic peptides (NPs) with a rank order of potency of CNP(1-22)>>BNP(1-26)>ANP(1-28). HS-142-1, a selective antagonist of the two recognized GC-coupled NPRs, inhibited CNP(1-22)-stimulated cGMP production in granulosa cell membranes in a dose-dependent manner. Also mRNAs for all three recognized NPRs were detected in granulosa cells using reverse transcriptase-polymerase chain reaction (RT-PCR). Serial dilution curves of granulosa cell extracts were parallel to the standard curve of synthetic CNP. Conclusion: These results indicate that CNP and its specific receptor are expressed in the granulosa cells of the pig ovary, and suggest that CNP may be a local autocrine and/or paracrine regulator via activation of its specific GC-coupled receptor, NPR-B.

Flow cytometry (FCM) is a unique technique that allows rapid quantitative measurement of multiple parameters on a large number of cells at the individual level. FCM is based on immunolabelling with fluorochrome-conjugated antibodies, leading to high sensitivity and precision while time effective sample preparation. FCM can be performed on tissue following enzymatic or mechanical dissociation. The expression of epithelial antigens and cytokeratin isoforms help in distinguishing tumor cells from adjacent epithelial cells and from tumor infiltrating leukocytes. Tumor phenotypes can be characterized on expression intensity, aberrancies and presence of tumor-associated antigens as well as their cell proliferation rate and eventual heteroploidy. FCM can measure quantitative expression of hormone or growth factor receptors, immunoregulatory proteins to guide adjuvant therapy. Expression of adhesion molecules tells on tumor’s capacity for tissue invasion and metastasis seeding. Tumor heterogeneity can be explored quantitatively and rare, potentially emerging, clones with poor prognosis can be detected. FCM is easily applicable on fine needle aspiration and in any tumor related biological fluids. FCM can also be used to detect circulating tumor cells (CTC) to assess metastatic potential at diagnosis or during treatment. Detecting CTC could allow early detection of tumors before they are clinically expressed although some difficulties still need to be solved. It thus appears that FCM should be in the pathologist tool box to improve cancer diagnosis, classification and prognosis evaluation as well as in orientating personalized adjuvant therapy and immunotherapy. More developments are still required to better known tumor phenotypes and their potential invasiveness

In order to study the molecular mechanism of the antioxidant effect of enzymatically hydrolyzed tuna dark meat peptides, this article uses alkaline protease to enzymatically hydrolyze tuna dark meat, and at the same time performs peptide sequencing using matrix-assisted laser dissociation time-of-flight mass spectrometry (MALDI TOF/TOF). Discovery Studio (DS) performed molecular docking. Finally, the antioxidant effect was verified through DPPH clearance experiments. The results show that the dominant peptide sequences in the tuna dark meat hydrolyzed polypeptides  are LAPGQ, GGGDPI, and PLRLP; through molecular simulation methods (Discover Studio, DS), the potential target of the above-mentioned enzymatic polypeptides was screened out to be Keap1, thus predicting antioxidant activity. It provides theoretical support for further research on enzymatic peptides. Through DPPH clearance experiments, it was found that both the enzymatic hydrolysate and LAPGQ, GGGDPI, and PLRLP have antioxidant activity, confirming their effects.

Stroke is a clinically defined syndrome of acute focal neurological deficit attributed to vascular injury (infarction, hemorrhage) of the central nervous system. Stroke is the second leading cause of death and disability worldwide. Stroke is not a single disease but can be caused by a wide range of risk factors, disease processes and mechanisms. Approximately 15% of strokes worldwide are the result of intracerebral hemorrhage, which can be deep (basal ganglia, brainstem), cerebellar or lobar. A minority (about 20%) of intracerebral hemorrhages are caused by macrovascular lesions (vascular malformations, aneurysms, cavernomas), venous sinus thrombosis or rarer causes.

Antioxidants are groups of compounds that neutralize free radicals and Reactive Oxygen Species (ROS) in the cell [1]. Antioxidant activity in food and beverages has become one of the most interesting features in the science community. These antioxidants provide protection against damage caused by free radicals played important roles in the development of many chronic diseases including cardiovascular diseases, aging, heart disease, anemia, cancer, and inflammation [2].

Stroke and acute myocardial infarction are primary global causes of mortality. Statistical studies have shown that acute myocardial infarction is responsible for around 9 million deaths each year. Ischemic stroke and myocardial infarction have a significant role in global adult physical disabilities. While reperfusion is vital for tissue recovery, it may paradoxically, inadvertently increase damage through oxidative stress, inflammation, and cell death. Early reperfusion procedures are currently the sole therapy to reduce infarct size. There are many mysteries about heart biology. It is not known the source of energy for myocardial tissues. The heart-beating force (120 mm Hg) cannot explain how erythrocytes are impelled through almost 95,000 km of capillaries in less than 5 minutes. A better knowledge of how the heart is oxygenated should allow the development of new therapies.