Novel Protein Tyrosine Phosphatase 1B Inhibitor-Geranylated Flavonoid from Mulberry Leaves Ameliorates Insulin Resistance.

Mulberry leaf is a common vegetable with a variety of beneficial effects, such as hypoglycemic activity. However, the underlying mechanism of its hypoglycemic effect have not been fully revealed. In this study, two flavonoid derivatives were isolated from mulberry leaves, a new geranylated flavonoid compound (1) and its structural analogue (2). The structures of compounds 1 and 2 were elucidated using spectroscopic analysis. To study the potential hypoglycemic properties of these compounds, their regulatory effects on protein tyrosine phosphatase 1B (PTP1B) were investigated. In comparison to oleanolic acid, compounds 1 and 2 showed significant inhibitory activities (IC50 = 4.53 ± 0.31 and 10.53 ± 1.76 µM) against PTP1B, the positive control (IC50 = 7.94 ± 0.76 µM). Molecular docking predicted the binding sites of compound 1 to PTP1B. In insulin-resistance HepG2 cell, compound 1 promoted glucose consumption in a dose-dependent manner. Furthermore, western blot and polymerase chain reaction analyses indicated that compound 1 might regulate glucose consumption through the PTP1B/IRS/PI3K/AKT pathway. In conclusion, geranylated flavonoids in mulberry leaves inhibite PTP1B and increase the glucose consumption in insulin-resistant cells. These findings provide an important basis for the use of mulberry leaf flavonoids as a dietary supplement to regulate glucose metabolism.

In vitro Antibiotic Susceptibility, Virulence Genes Distribution and Biofilm Production of Staphylococcus aureus Isolates from Bovine Mastitis in the Liaoning Province of China.

PURPOSE: The aim of this study was to identify the subtype, characterize the antimicrobial resistance, determine the virulence gene distribution, and analyze the biofilm production of Staphylococcus aureus isolates from bovine mastitis milk samples in the Liaoning Province of China. MATERIALS AND METHODS: In total, 56 Staph. aureus isolates were collected and identified in this study; the isolates were divided into different spa types based on the sequence of the polymorphic X region of the spa gene. Additionally, antimicrobial susceptibility was investigated using the broth microdilution method, and 18 virulence genes were detected using PCR. Biofilm formation was measured by spectrophotometry with crystal violet staining and observed using confocal laser scanning microscopy. RESULTS: There were 12.12% (56/462) milk samples that were positive for Staph. aureus. These isolates were nonsusceptible to sulfamethoxazole (100%), penicillin (76.9%), daptomycin (76.79%), clindamycin (69.64%), and oxacillin (60.71%); however, the majority of the isolates (80.4%) were susceptible to amoxicillin/clavulanate. The predominant virulence genes encoded the cytotoxins, hla (94.64%) and hlb (89.29%), and the adhesion factors clfA (89.29%), clfB (89.29%), and fnbB (80.36%). Comparatively, virulence genes related to other adhesion factors such as cna (8.93%) and enterotoxins, such as seg (26.79%), sea (16.07%), seb (7.14%), and sec (7.14%) were detected at relatively lower rates. The following eight spa types were identified: t267 (35.84%), t730 (22.64%), t518 (15.09%), t1190 (11.32%), t1456 (9.43%), t224 (1.88%), t9129 (1.88%), and t177 (1.88%). The highest biofilm production was observed for t267. Staph. aureus exhibited various patterns of biofilm formation, with the biofilm often being associated with a tower-shaped structure or a thicker biofilm. CONCLUSION: Our results indicated that Staph. aureus isolates from dairy cows with mastitis in the Liaoning Province of China were non-susceptible to sulfamethoxazole, penicillin, daptomycin, oxacillin, and clindamycin. Additionally, the most prevalent subtype was t267, which displayed resistance to multiple antimicrobial agents and harbored several virulence genes, including clfA, clfB, fnbB, hla, and hlb.

Resistance to ß-lactam antibiotic may influence nanH gene expression in Trueperella pyogenes isolated from bovine endometritis.

Virulence could be modulated by many instinctive and environmental factors including oxygen, osmolarity and antimicrobial agents. This study aimed to investigate the correlation between drug resistance and the nanH expression in Trueperella pyogenes (T. pyogenes). Minimum inhibitory concentrations (MICs) of 6 ß-lactam antimicrobial agents (penicillin G, amoxicillin, oxacillin, cefazolin, ceftiofur, and ampicillin) against T. pyogenes were tested by standard broth dilution method according to the protocols of the Clinical and Laboratory Standards Institute (CLSI), and real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR) was selected to investigate the mRNA expression levels of the nanH in T. pyogenes. All the isolates were resistant to atleast 2 of antimicrobial agents, and multidrug resistance (resistance to atleast 3 antimicrobials) was observed in 84.38% (27/32) of isolates. The mRNA expression levels of the nanH were significantly higher in comparison with that in ATCC19411, as the resistance profile enlarged, the nanH mRNA expression levels decreased in T. pyogenes. These results indicated that ß-lactam antibiotic resistance in T. pyogenes may alter the expression of the nanH.

Protective effects of apocynin on atrial electrical remodeling and oxidative stress in a rabbit rapid atrial pacing model.

It has been proposed that apocynin might be used in the prevention and management of atrial fibrillation (AF). The purpose of this study was to investigate the effects of apocynin on atrial electrical remodeling and oxidative stress promoted by rapid atrial pacing (RAP) in rabbits. New Zealand white rabbits were subjected to RAP with or without apocynin treatment. Serial electrophysiological studies (EPS) were performed at baseline and every half hour after RAP onset. Superoxide dismutase (SOD) and lactate dehydrogenase (LDH) activities and Ca²âº content in tissue homogenates of both atria were assayed after EPS. In the RAP group but not in the sham-operated and RAP with apocynin groups, atrial effective refractory periods (AERPs) at cycle length of 200 and 150 ms shortened most clearly by 20.8 ± 10.2 ms at 3 h (P < 0.001) and by 12.8 ± 11.1 ms at 2 h (P < 0.05) respectively, and AERP rate adaptation decreased to minus values. Higher AF inducibility (66.7%) and longer AF duration (an average of 37.8 min) were presented in the RAP group. Compared with the other groups, SOD activity was lower, and LDH activity and Ca²âº content were higher in the RAP group. Similar differences were not found between the sham-operated and the RAP with apocynin treatment groups. These data show that apocynin attenuates the development of atrial electrical remodeling in a short period of 3-hour RAP, and reduces RAP-mediated inducibility and duration of AF in this model.

Protective effect of piperine on electrophysiology abnormalities of left atrial myocytes induced by hydrogen peroxide in rabbits.

AIMS: Piperine had protective effects on oxidative stress damage of ventricular myocytes by hydrogen peroxide (H2O2). In this study we aimed to explore the protective effect of piperine on abnormalities of the cardiac action potential (AP) and several ion currents induced by hydrogen peroxide (H2O2) in single rabbit left atrial myocyte. MAIN METHODS: Conventional microelectrodes were used to record action potential duration (APD), resting membrane potential (RMP) and some ion currents (ICa,L,Ito,IK1 and Ikur,ect.), before and after H2O2 administration with or without piperine. KEY FINDINGS: The piperine (7 µmol/L) had no significant effect on APD, ICa,L,Ito,IK1 and Ikur and their channel dynamics. In the presence of 50 µmol/L H2O2, APD50 and APD90 shortened (P<0.01), amplitude of RMP decreased (P<0.05), the peak of ICa,L reduced significantly (P<0.05). Piperine (7 µmol/L) significantly alleviated the inhibiting effect of H2O2 on APD and ICa,L (P<0.01) and protected the changes of ICa,L dynamics induced by H2O2. The peak current of Ito was reduced significantly (P<0.05); Piperine (7 µmol/L) significantly alleviated the inhibiting effect of H2O2 on Ito (P<0.01). In addition, piperine protected the changes of Ito dynamics induced by H2O2. The peak current of IK1 and IKUr was significantly reduced (P<0.05); Piperine (7 µmol/L) alleviated the inhibiting effect of H2O2 on IK1 and IKUr significantly (P<0.01). In addition, piperine protected the changes of IKUr dynamics induced by H2O2. SIGNIFICANCE: These results suggest that piperine effectively protects atrial myocytes from oxidative stress injury in atrial electrophysiology.

A comparative proteomic study identified calreticulin and prohibitin up-regulated in adrenocortical carcinomas.

BACKGROUND: Identifying novel tumor biomarkers to develop more effective diagnostic and therapeutic strategies for patients with ACC is urgently needed. The aim of the study was to compare the proteomic profiles between adrenocortical carcinomas (ACC) and normal adrenocortical tissues in order to identify novel potential biomarkers for ACC. METHODS: The protein samples from 12 ACC tissues and their paired adjacent normal adrenocortical tissues were profiled with two-dimensional electrophoresis; and differentially expressed proteins were identified by mass spectrometry. Expression patterns of three differently expressed proteins calreticulin, prohibitin and HSP60 in ACC, adrenocortical adenomas (ACA) and normal adrenocortical tissues were further validated by immunohistochemistry. RESULTS: In our proteomic study, we identified 20 up-regulated and 9 down-regulated proteins in ACC tissues compared with paired normal controls. Most of the up-regulated proteins were focused in protein binding and oxidoreductase activity in Gene Ontology (GO) molecular function classification. By immunohistochemistry, two biomarkers calreticulin and prohibitin were validated to be overexpressed in ACC compared with adrenocortical adenomas (ACA) and normal tissues, but also calreticulin overexpression was significantly associated with tumor stages of ACC. CONCLUSION: For the first time, calreticulin and prohibitin were identified to be novel candidate biomarkers for ACC, and their roles during ACC carcinogenesis and clinical significance deserves further investigation. VIRTUAL SLIDES: The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1897372598927465.

Hyperpolarization activated cation current (I(f)) in cardiac myocytes from pulmonary vein sleeves in the canine with atrial fibrillation.

OBJECTIVE: To investigate the characteristics of ectopic automaticity and cation current (I(f)) of cardiac myocytes from pulmonary vein sleeves (PVs) in canines with atrial fibrillation. METHODS: The canines (8-10 years old) were subjected to long-term, rapid atrial pacing (RAP) for 10 weeks, which induced the atrial fibrillation model. Disassociation of PVs of canines yielded single cardiac myocytes from a Landengorff column. Action potential, I(f) and hyperpolarisation activated cyclic nucleotide-gated (HCN) currents were measured with the patch-clamp technique. RESULTS: Compared with the control group, cardiac myocytes from the RAP canine PVs had spontaneous diastolic depolarization, shorter action potential duration, and larger I(f) densities. In the group of RAP cells, the half maximal activation potential (V(1/2)) was found to be less negative (-105.5 ± 5.2 mV) compared to control cells (-87.3 ± 4.9 mV). Current densities of I(f) were increased significantly by ß-adrenergic receptor stimulation with isoproterenol and caused an acceleration of current activation. In contrast, I(f) currents in the RAP were reduced by carvedilol, a selective beta-adrenergic receptor. Another important finding is that HCN4-based channels may make a significant contribution to I(f) in PVs cells, but not HCN2. Meanwhile, HCN4 current significantly increases in canine PVs cardiac myocytes with RAP. CONCLUSIONS: The spontaneous action potential and larger I(f) current were observed in the PVs cardiac myocytes using RAP, which may contribute to more ectopic activity events to trigger and maintain atrial fibrillation.

[Effect of Tangyikang in improving the function of pancreatic islet beta cells in patients with latent autoimmune diabetes mellitus in adults].

OBJECTIVE: To investigate the effect and mechanism of Tangyikang (TYK) for improving pancreatic islet beta cell function in patients with latent autoimmune diabetes mellitus in adults (LADA). METHODS: Seventy-four LADA patients were randomly assigned to two groups. The 37 patients in the treatment group were treated with TYK decoction (one dose consisted of red ginseng 10 g, milkvetch root 30 g, lilyturf root 15 g, wild weed 10 g, coptis root 15 g, cape-jasmine fruit 10 g, giant knotweed rhizome 10 g, safflower 10 g and moutan bark 10 g) combined with insulin therapy, and the 37 in the control group treated with insulin therapy alone, and the course for all was 3 months. Changes of glycosylated hemoglobin, index of pancreatic islet beta-cell function (delta CP(2h)/delta BS(2h)), serum interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were observed before and after treatment. RESULTS: All the above-mentioned indexes were improved after treatment in both groups, the post-treatment data showed significant difference between groups in delta CP(2h)/delta BS(2h), (0.258 +/- 0.106 vs 0.168 +/- 0.054, higher in the treatment group, t = 4.626, P < 0.01), but with insignificant difference in glycosylated hemoglobin (t = 0.441, P = 0.660). Besides, the dosage of insulin used in the treatment group was less than that in the control group (t = -4.169, P < 0.01); covariance analysis showed, through excluding impact of different dosages insulin used, IL- 4 level was higher (F = 24.217, P < 0.01) and IFN-gamma level was lower (F = 14.198, P < 0.01) in the treatment group than those in the control group. CONCLUSIONS: TYK could improve the function of islet beta-cell, its possible mechanism is related with the regulation on cell immunity and the correction of T-lymphocyte subsets (Th1/Th2 ratio) imbalance.

[Clinical study on Tangweikang in treating diabetic gastroparesis].

OBJECTIVE: To investigate clinical effects and mechanism of Tangweikang (TWK) in treating diabetic gastroparesis. METHODS: Ninety diabetic gastroparesis patients were randomly assigned to 3 groups. Besides conventional hypoglycemic treatment, the 30 patients in the treated group were given TWK and the 30 in the control group were given Domperidone additionally, while to the 30 in the blank group, no additional drug was given. The clinical efficacy and the changes in level of motilin and gastric emptying rate were observed. RESULTS: TWK showed significant effects in improving clinical symptoms of patients, increasing gastric emptying rate, promoting gastrointestinal kinetics, shortening gastric emptying time and was beneficial to the control of blood sugar, including the 2 h post-prandial blood sugar and fructosamine. The curative rate and total effective rate in the treated group were 63.33% (19/30) and 93.33% (29/30) respectively, significantly different to those in the control group 26.67% (8/30) and 63.33%, also different to those in the blank group 23.33% (3/ 30) and 10.00%, respectively (P < 0.01). The clinical efficacy in the treated group was superior to that in the other two groups. CONCLUSION: TWK has favorable therapeutic efficacy in treating DGP.