Oxidative Stress-Mediated Antibacterial Activity of the Total Flavonoid Extracted from the Agrimonia pilosa Ledeb. in Methicillin-Resistant Staphylococcusaureus (MRSA).

(1) Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a zoonotic pathogen that causes endocarditis, pneumonia, and skin diseases in humans and livestock. (2) Methods: The antibacterial effect of the total flavonoid against MRSA (ATCC43300) extracted from the Agrimonia pilosa Ledeb. (A. pilosa Ledeb) was evaluated by the microdilution method. The oxidative stresses in MRSA were evaluated by the levels of intracellular hydrogen peroxide (H2O2), reactive oxygen species (ROS), and oxidative stress-related genes. The DNA oxidative damage was tested by the 8-hydroxy-2'-deoxyguanosine (8-OHdG) and DNA gel electrophoresis. The differentially expressed proteins were determined by the method of SDS-PAGE and NanoLC-ESI-MS/MS, while the mRNAs of differential proteins were determined by Real-Time PCR. The changes of ultra-structures in MRSA were observed by Transmission Electron Microscope (TEM). (3) Results: The minimum inhibitory concentration (MIC) of the total flavonoid against MRSA was recorded as 62.5 µg/mL. After treatment with the total flavonoid, the levels of intracellular H2O2 and ROS were increased and the gene expressions against oxidative stress (SodA, katA, TrxB) were decreased (p < 0.01), while the gene expression for oxidative stress (PerR) was increased (p < 0.01). The level of intracellular 8-OHdG in MRSA was increased (p < 0.01) and the DNA was damaged. The results of TEM also showed that the total flavonoid could destroy the ultra-structures in the bacteria. (4) Conclusions: The total flavonoid extracted from the A. pilosa Ledeb can induce the oxidative stress that disturbed the energy metabolism and protein synthesis in MRSA.

Recent advances on the intervention sites targeting USP7-MDM2-p53 in cancer therapy.

The ubiquitin-specific protease 7 (USP7)-murine double minute 2 (MDM2)-p53 network plays an important role in the regulation of p53, a tumor suppressor which plays critical roles in regulating cell growth, proliferation, cell cycle progression, apoptosis and immune response. The overexpression of USP7 and MDM2 in human cancers contributes to cancer initiation and progression, and their inhibition reactivates p53 signalings and causes cell cycle arrest and apoptosis. Herein, the current state of pharmacological characterization, potential applications in cancer treatment and mechanism of action of small molecules used to target and inhibit MDM2 and USP7 proteins are highlighted, along with the outcomes in clinical and preclinical settings. Moreover, challenges and advantages of these strategies, as well as perspectives in USP7-MDM2-p53 field are analyzed in detail. The investigation and application of MDM2 and USP7 inhibitors will deepen our understanding of the function of USP7-MDM2-p53 network, and feed in the development of effective and safe cancer therapies where USP7-MDM2-p53 network is implicated.

The emerging nature of Ubiquitin-specific protease 7 (USP7): a new target in cancer therapy.

Human ubiquitin-specific protease 7 (USP7) is a deubiquitinating enzyme that removes the ubiquitin (Ub) protein and spares substrates from degradation. Given its regulation of proteins involved in several cellular processes, abnormal expression and activity of USP7 are associated with several types of disease, including cancer. In this review, we summarize the developments in our understanding of USP7 over the past 5 years, focusing on its role in related cancers. Furthermore, we discuss clinical studies of USP7, including in vivo and pharmacological studies, as well as the development of USP7 inhibitors. A comprehensive understanding of USP7 will expand our knowledge of the structure and function of USP7-mediated signaling and shed light on drug discovery for different diseases in which USP7 is implicated.

Antimicrobial mechanism of strictinin isomers extracted from the root of Rosa roxburghii Tratt (Ci Li Gen).

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Rosa roxburghii Tratt (Ci Li Gen) is a kind of Chinese ethnomedicine in Gui Zhou province, used for the treatment of abdominal pain, acute bacillary dysentery, gastroenteritis and other diseases in human and livestock. AIM OF THE STUDY: The aim of this study was to isolate and identify the effective antimicrobial components from the ethyl acetate extract of the Ci Li Gen and to investigate its antimicrobial mechanism afterwards. MATERIALS AND METHODS: The effective antimicrobial components in the ethyl acetate extract from the Ci Li Gen were isolated by high-performance liquid chromatography (HPLC) and identified by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR). The antibacterial activity was evaluated by the minimum inhibition concentration (MIC) measured by microdilution technique. The antibacterial mechanism was investigated by the time-kill curve, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) combined with NanoLC-ESI-MS/MS, intracellular esterase activity detected by Flow cytometry, and the ultrastructural changes of the Escherichia coli ATCC 25922 observed by scanning electron microscope (SEM). RESULTS: The effective antimicrobial component (peak 4) was identified as strictinin isomers by HRMS and NMR. The MIC of strictinin isomers against E. coli was 0.125 mg/mL. With respect to the negative control group, the results of SDS-PAGE and NanoLC-ESI-MS/MS showed that the up-regulated proteins of the strictinin isomers treated group were Metal-binding protein ZinT, 30S ribosomal protein S4 and 50S ribosomal protein L4, while the down-regulated protein was hydroperoxide reductase subunit C. Moreover, in the strictinin isomers treated group, the esterase activity in the E. coli cells was reduced and the bacteria E. coli became atrophied, pitted and contorted, and the surface of E. coli was rough and blurred. CONCLUSIONS: According to the above results, the antimicrobial mechanism of strictinin isomers against E. coli were oxidative stress and protein synthesis disorder, which inhibited the activity of the enzymes required for bacterial growth and metabolism. These findings reflected the pleiotropic effects of strictinin isomers, making it a promising antimicrobial agent for pharmaceutical research.

Unraveling the complexity of complex mixtures by combining high-resolution pharmacological, analytical and spectroscopic techniques: antidiabetic constituents in Chinese medicinal plants.

Medicinal plants have been widely used as (poly)pharmacological remedies and constitute a rich source for antidiabetic drug discovery. In the present study, forty medicinal plant samples collected in China were tested for inhibitory activity against α-glucosidase, α-amylase, and protein-tyrosine phosphatase 1B (PTP1B). Crude ethyl acetate extracts of Dioscorea bulbifera L., Boehmeria nivea Gaudich, Tinospora sagittata Gagnep. and Persicaria bistorta (L.) Samp. showed dual inhibitory activity towards α-glucosidase and PTP1B, and were chosen for further investigation. Subsequent dual high-resolution α-glucosidase/PTP1B profiling or triple high-resolution α-glucosidase/α-amylase/PTP1B profiling combined with HPLC-HRMS and NMR spectroscopy led to the identification of 28 metabolites with one or more bioactivities. Among these, three new phenanthrenes were identified from D. bulbifera, including one new biphenanthrene (10) exhibiting promising dual inhibitory activity towards α-glucosidase and PTP1B with IC50 values of 2.08 ± 0.19 and 3.36 ± 0.25 µM, respectively. Two triterpenoids and one fatty acid from B. nivea and T. sagittata as well as some commercially available fatty acids showed strong PTP1B inhibitory activity with IC50 values in the range of 4.89 ± 0.38 to 53.77 ± 4.20 µM.

Role of Glucagon-Like Peptide-1 and Gastric Inhibitory Peptide in Anorexia Induction Following Oral Exposure to the Trichothecene Mycotoxin Deoxynivalenol (Vomitoxin).

Deoxynivalenol (DON), which is a Type B trichothecene mycotoxin produced by Fusarium, frequently contaminates cereal staples, such as wheat, barley and corn. DON threatens animal and human health by suppressing food intake and impairing growth. While anorexia induction in mice exposed to DON has been linked to the elevation of the satiety hormones cholecystokinin and peptide YY3-36 in plasma, the effects of DON on the release of other satiety hormones, such as glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), have not been established. The purpose of this study was to determine the roles of GLP-1 and GIP in DON-induced anorexia. In a nocturnal mouse food consumption model, the elevation of plasma GLP-1 and GIP concentrations markedly corresponded to anorexia induction by DON. Pretreatment with the GLP-1 receptor antagonist Exendin9-39 induced a dose-dependent attenuation of both GLP-1- and DON-induced anorexia. In contrast, the GIP receptor antagonist Pro3GIP induced a dose-dependent attenuation of both GIP- and DON-induced anorexia. Taken together, these results suggest that GLP-1 and GIP play instrumental roles in anorexia induction following oral exposure to DON, and the effect of GLP-1 is more potent and long-acting than that of GIP.

The immunosuppressive characteristics of FB1 by inhibition of maturation and function of BMDCs.

Fumonisin B1 (FB1) is one kind of mycotoxins that has the neurotoxicity, carcinogenicity, hepatotoxicity and immunotoxicity produced by the fungus Fusarium verticillioides, which commonly infects corn and other crops and is harmful to animal and human health upon consumption of FB1-contaminated feed or food. However, the mechanism of immunotoxicity, especially the immunosuppression induced by FB1 is still unclear. The most pivotal cells in the induction of immune responses are dendritic cells (DCs). In this study, we used murine bone marrow-derived dendritic cells (BMDCs) as a model system to elucidate the effect of FB1 on the function of BMDCs through biological methods. We found that FB1 reversed the morphological changes and enhanced the endocytosis of FITC-dextran in LPS-treated BMDCs. At the same time, FB1 decreased the LPS-induced expressions of MHC II, C[1]D80 and CD86 molecules in BMDCs (p<0.05), as well as the T-cell stimulatory capacity of BMDCs (p<0.01). Moreover, the secretions of IL-6, IL-10 and IL-12, but not TNF-α induced by LPS exposure were suppressed by FB1 in a dose dependent (p<0.01). It was considered that the immunosuppressive effects of FB1 were mainly caused by changing the morphology and interfering with the process of antigen uptake, processing and presentation. The results highlighted that FB1 had the capacity to modulate the immune responses of BMDCs.

Inhibitory effects of deoxynivalenol on gastric secretion in rats.

Deoxynivalenol (DON) is a common mycotoxin produced by Fusarium sp. in cereals and foods. Ingestion of contaminated foodstuffs can cause digestive disorders in various animals. Many researchers focus on its toxicity and the pathological damage and absorptive function in the intestines. However, the effect of DON on gastric function is still unclear. The objective of the current study was to evaluate the impact of DON on gastric secretion. Rats were gavaged with DON at the dose of 0, 1, 5, and 25 mg/kg of body weight (bw). Gastric fluids were gathered by pylorus ligation 0.5 h after DON exposure. The results indicate that the volume of gastric fluid decreased by 25, 51, and 61% compared with the control, respectively. The pH increased to 3.2, 3.81, and 6.65 in the 1, 5, and 25 mg/kg bw DON group, compared with the control (1.9). To examine the mucosal injuries, the stomach tissues were made into hematoxylin and eosin slides. Histopathology observations suggest that no mucosal lesions were observed until DON exposure at 25 mg/kg bw. Additionally, the gastrin secretion in the fluids and mRNA expression in tissues were determined by the radioimmunoassay and real-time PCR assay, respectively. The results indicated that both significantly decreased in DON-exposed rats compared with the control. Taken together, DON exposure reduced gastric secretion in rats. Low gastrin secretion and mRNA expression play a major role, unless mucosal lesions by high DON exposure are present.

Immune-enhancing activity of polysaccharides from Cyrtomium macrophyllum.

The goal of the present study was to investigate the immune-enhancing activity of polysaccharides from Cyrtomium macrophyllum (CMP). Two experiments were carried out. In immunosuppression experiment, the immune-enhancing effect of CMP in immunosuppressive mice was performed. The results showed that CMP at high and medium doses was able to overcome the CY-induced immunosuppression, significantly increases the thymus and spleen indices, enhances lymphocyte proliferation activity and macrophage function, improves immunoglobulin and cytokines levels compared with negative control group. In macrophage immunomodulatory experiment, the immune-enhancing effect of CMP in RAW264.7 cells was measured. The results showed that CMP induced the elevation of NO production, TNF-α secretion and iNOS protein of RAW264.7 cells. CMP can also strongly increase NF-κB levels in nuclear, which is an important transcription factor that can modulate expressions of iNOS, NO and TNF-α. Therefore, the CMP could be an effective immunomodulatory agent.

Identification and characterization of dermatophyte species and strains with PCR amplification.

The aim of the present study was to use two polymerase chain reaction (PCR) methods, with (GACA)4 and non-transcribed spacer (NTS) as primers, to identify and characterize dermatophyte isolates from dogs and cats to a species and strain level. A total of 45 isolates from nine dermatophyte species were collected from pet dogs and cats and subjected to PCR amplification with the microsatellite primer (GACA)4. Dermatophyte strains of three of the same species collected from four cities were subjected to PCR amplification with the NTS primer set. These two PCR methods were applied to identify and characterize the dermatophyte isolates to a species and strain level. Regional differences among the strain specificities were also examined. The results from PCR with (GACA)4 demonstrated that strains from the same species produced similar PCR product band patterns. In addition, these patterns differed among species, indicating that (GACA)4 primer-based PCR was able to distinguish between the various dermatophyte species. By contrast, dermatophyte isolates and/or strains within the same species revealed various band patterns with NTS-based PCR. In addition, the results indicated that regional differences contributed to the variations in PCR product band patterns. Therefore, the results of the present study indicate that the NTS-based PCR method is efficient in distinguishing dermatophytes to the strain level, while a combination of (GACA)4 and NTS primer-based PCR methods is able to clarify dermatophyte isolates to a species and strain level. The present study provides information concerning the identification of pathogenic fungi and the epidemiological characteristics of fungal skin diseases.

Immuno-enhancement effects of ethanol extract from Cyrtomium macrophyllum (Makino) Tagawa on cyclophosphamide-induced immunosuppression in BALB/c mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Cyrtomium macrophyllum (Makino) Tagawa has been traditionally used as a herbal medicine for the treatment of various infectious diseases such as tapeworm infestation, colds, and viral diseases. However, no systematic study of the immunity of Cyrtomium macrophyllum ethanol extracts (CM) has yet been reported. The present work evaluates these traits. MATERIALS AND METHODS: 120 male BALB/c mice were divided into 6 groups of 20 mice each: (1) normal group (sterile physiological saline), which served as a blank control; (2) model group (Cyclophosphamide, CY) group (sterile physiological saline), which served as a negative control; (3) low-dose CM (50 mg/kg BW); (4) intermediate-dose CM (100 mg/kg BW); (5) high-dose CM (200 mg/kg BW); (6) CM group (200 mg/kg BW). CY (0.2 ml) was administered via intraperitoneal injection. The other regimens were administered via gavage in 0.2 ml solution. Phytochemical of CM was characterized by HPLC-LTQ-Orbitrap. The acute toxicity effect of the ethanol extract of Cyrtomium macrophyllum was also investigated. RESULTS: The spleen and thymus indices of mice receiving low, intermediate, and high doses of CM recovered more quickly than those of CY mice, and they did so in a dose-dependent manner. These mice also showed higher T cell and B cell proliferation responses and macrophage function than those of CY mice, and their serum levels of interleukin-6 and interferon-γ had become normal. In acute toxicity test, CM exhibited no mortality and behavioral changes in mice. Quantitative phytochemical analysis showed flavonoids, polyphenols, and tannins to be the major compounds present in the extract, at 27.64%, 30.87%, and 11.22%, respectively. We found that 16 compounds were characterized by the interpretation of their mass spectra obtained by the MS/MS. CONCLUSION: The current study demonstrates that Cyrtomium macrophyllum ethanol extract improved immune function in CY-treated mice.

N-octyl-N-arginine-chitosan (OACS) micelles for gambogic acid oral delivery: preparation, characterization and its study on in situ intestinal perfusion.

CONTEXT: Gambogic acid (GA) can inhibit the growth of various cancer cells. However, the low bioavailability caused by insolubility, limits its clinical application. L-arginine is always used with GA to form a complex to obtain the higher solubility. Moreover, guanidyl group from arginine, which can facilitate the cellular uptake, was identified. OBJECTIVE: In this study, L-arginine and chitosan (CS) were used for the first time to prepare N-octyl-N-arginine CS (OACS), a novel amphiphilic carrier for GA with solubility- and absorption-enhancing functions; the characterization of the GA loaded OACS micelles (GA-OACS) and its absorption-enhancing effect were also investigated. MATERIALS AND METHODS: GA-OACS were prepared by the dialysis method. The formed micelles were characterized and evaluated by atomic force microscope (AFM), dynamic light scattering, differential scanning calorimeter (DSC), solubility test, in vitro release and in situ intestinal perfusion. RESULTS: The GA-OACS micelles were successfully prepared attaining a 35.3% drug loading and 82.2% entrapment efficiency. GA-OACS had a homogeneous particle size of 160.3 nm; +21.8 mv zeta potential with smooth continuous surface was observed by using AFM. DSC diagram suggested that GA was encapsulated in the micelles. Meanwhile, GA encapsulated in micelles exhibited a desirable slow release in vitro experiment. The solubility of GA in OACS micelles was increased up to 3.16 ± 0.13 mg/mL, 2320 times than that of free GA. The single pass perfusion showed that the absorption of GA-OACS micelles was enhanced 3.6-fold, 2.1-fold and 2.2-fold for jejunum, ileum and colon, respectively. DISCUSSION AND CONCLUSION: OACS provided excellent ability of drug loading, increasing solubility and enhanced absorption for GA, which indicated that OACS micelles as an oral drug delivery carrier may have potential research and application values.

[Study on intestinal absorption kinetics of apigenin in rats].

To establish an in situ single-way intestinal perfusion model, in order to study the intestinal absorption kinetics of AP. The concentration of AP in the perfusate was determined by HLPC. The results showed different AP concentrations in all intestinal segments, with the fastest absorption rate in duodenum, which was followed by jejunum, ileum and colon. In general, the constant absorption rate (Ka) of AP in duodenum and jejunum first increased and then decreased with the rise in drug concentration (P <0. 05); the absorption mechanism may be related to active transport and facilitated diffusion factors. The constant absorption rate (Ka) of AP in ileum and colon generally kept unchanged with the rise diffusion in drug concentration, the absorption mechanism may be related to passive.

T-2 toxin, zearalenone and fumonisin B1 in feedstuffs from China.

A total of 420 feedstuff samples were collected from China to determine and quantify T-2 toxin (T-2), zearalenone (ZEN) and fumonisin B1 (FB1). The contents of mycotoxins were determined by reverse-phase high-performance liquid chromatography with three-step cleanup and fluorescence detection. The mean recoveries of mycotoxins in spiked feedstuffs ranged from 72.2% to 95%. The limits of detection and quantification ranged from 1.8 to 5.7 and 6 to 19 µg/kg, respectively. Of the 420 analysed feedstuff samples, the incidence of T-2, ZEN and FB1 was 79.5%, 85.2% and 96.1%, respectively; levels detected ranged from 10-735, 35-1478 and 20-6568 µg/kg, respectively. The results suggest a risk for domestic animals and humans. Further, the procedure was found to be suitable for determination of mycotoxins in feedstuffs and can be used for routine analysis. This is the first report in China on natural contamination of feedstuffs with these mycotoxins.

Characterization and comparison of Fumonisin B(1)-protein conjugates by six methods.

In order to generate an antibody against a small hapten molecule, the hapten is cross-linked with carrier protein to make it immunogenic. In this study, the hapten (Fumonisin B(1), FB(1)) was coupled to ovalbumin (OVA) and bovine serum albumin (BSA), respectively by a short cross-linker reagent (glutaraldehyde, GA). To develop a technique for detecting the conjugation, the hapten-protein conjugates (FB(1)-OVA and FB(1)-BSA) were characterized thoroughly by ultraviolet (UV) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), respectively. The molecular weights of FB(1)-BSA and FB(1)-OVA were 74,355.301 Da and 48,009.212 Da, respectively determined by the method of MALDI-TOF-MS. The molecular coupling ratios were 11 and 5 in FB(1)-BSA and FB(1)-OVA, respectively. In this experiment, MALDI-TOF-MS was selected as the most efficient method to evaluate the cross-linking effect and calculate the molecular coupling ratio.

A mitochondria-mediated apoptotic pathway induced by deoxynivalenol in human colon cancer cells.

Deoxynivalenol (DON), known colloquially as "vomitoxin", is a pathogenic mycotoxin produced by Fusarium fungi. Human food poisoning outbreaks, with nausea, diarrhea, and vomiting as primary symptoms, have been associated with Fusarium-infected cereals. Therefore, this study was designed to determine the molecular aspects of DON in human colon cancer cells (HT-29). To this aim, we have monitored the effects of DON on (i) cellular morphological changes via optical and transmission electron microscopy, especially in regards to cell viability and mitochondria changes, and (ii) its effects on key regulators of cell apoptosis, including cytochrome c, caspase-9, caspase-3, Bcl-2, Bax, and Bid. Our results showed that DON treatment inhibited cell proliferation, induced significant morphological changes, and promoted the activation of cytochrome c and caspases. Furthermore, changes in Bcl-2, Bax, and Bid expression were detected. The relative expression profile of Bcl-2 was contrary to that of Bax and Bid, as Bcl-2 expression decreased as the concentrations DON increased, reaching a minimum at the highest concentration of DON. We concluded that DON-induced apoptosis was caused by mitochondrial dysfunction and subsequent release of cytochrome c into the cytoplasm and successive activation of caspases, and this was likely regulated by Bcl-2 family proteins.

The individual and combined effects of deoxynivalenol and aflatoxin B1on primary hepatocytes of Cyprinus carpio.

Aflatoxin B(1) (AFB(1)) and deoxynivalenol (DON) are important food-borne mycotoxins that have been implicated in animal and human health. In this study, individual and combinative effects of AFB(1) and DON were tested in primary hepatocytes of Cyprinus carpio. The results indicated that the combinative effects of AFB(1) and DON (0.01 µg/mL AFB(1) and 0.25 µg/mL DON; 0.02 µg/mL AFB(1) and 0.25 µg/mL DON; 0.02 µg/mL AFB(1) and 0.5 µg/mL DON) were higher than that of individual mycotoxin (P < 0.05). The activity of AST, ALT and LDH in cell supernatant was higher than that of control group (P < 0.05) when the mycotoxins were exposed to primary hepatocytes for 4 h. The decreased cell number was observed in tested group by inverted light microscopy. The mitochondrial swelling, endoplasmic reticulum dilation and a lot of lipid droplets were observed in primary hepatocytes by transmission electron microscope. Therefore, this combination was classified as an additive response of the two mycotoxins.

Isolation and identification of a strain of Aspergillus tubingensis with deoxynivalenol biotransformation capability.

Deoxynivalenol (DON) is one of the most common contaminants of various foodstuffs. A biotransformation system was used in order to lessen the toxicity of DON. A strain of Aspergillus (NJA-1) was isolated from soil and cultured in an inorganic salt medium containing DON. Bt2a/Bt2b primers were used to amplify the beta-tubulin gene of NJA-1. Sequence analysis the PCR product and morphology observation indicated that NJA-1 belonged to Aspergillus tubingensis (aerobic fungi). The DNA sequence information of the PCR product was deposited in GenBank (accession number DQ9025790). The DNA sequence had 99% similarity to the Aspergillus tubingensis accession number AY820009. An unknown compound in NJA-1 showed the ability to convert DON into another product. The molecular weight of the bioconversion product was 18.1 D (H2O) larger than that of DON. The analysis showed that DON could be hydrolyzed by NJA-1. The mean DON biotransformation rate was 94.4% after two weeks of cultivation. The finding presents a new method for DON biotransformation.

[Identification of a bacterium with activities of inhibiting growth of fungi].

HB02 is characterized as a new microbiological agent that has the potential to decrease the toxicity of mildewed wheat containing Deoxynivalenol (DON). To explore whether HB02 could inhibit the growth of fungi, a spore suspension of Aspergillus flavus or Gibberellazeae was incubated with or without HB02 in PYG medium at 28 degrees C for 15d. The mycelium was weighed after 3, 6, 9, 12, 15 d of incubation, respectively. The result showed that the growth of these two important fungi was significantly inhibited by co-cultivation with HB02. Besides, HB02 was confirmed as Lactobacillus curvatus by its microbiological characters and the 16s-23s rRNA sequence. In conclusion, HB02, identified as Lactobacillus curvatus, prevent the effects of mycotoxins in contaminated feed by inhibiting the growth of fungi. Other detoxification ways of HB02 remain further study.

The intravenous glucose tolerance test in water buffalo.

OBJECTIVE: The response to intravenous glucose loading in the buffalo using the intravenous glucose tolerance test (IGTT) was investigated to provide a reference for intravenous glucose injection in buffaloes. METHOD: Twelve healthy, fasted, male swamp buffaloes were divided into three groups. Group I: six buffaloes were given 50% glucose at a dosage of 1 g/kg body weight via the jugular vein. Group II: three buffaloes received normal saline. Group III: three buffaloes were not injected. Blood samples were taken from the opposite vein at 60 and 10 min pre-injection (pre60 and pre10), and at 1, 5, 10, 30, 60, 120, 180, 240, 300, 360 and 420 min post-glucose injection (PGI). Plasma glucose was analyzed by the oxidase method. Insulin and glucagon were soon determined with a human radioimmunoassay kit. The insulin (pmol/l)/glucose (mmol/l) ratios (IGR) were also calculated for each sampling time. RESULTS: Mean plasma glucose, insulin and glucagon concentrations of buffaloes in groups II and III were similar at all the sampling times (p > 0.05) and the curves of the IGR for group II and group III were flat throughout. Group I Buffaloes showed an immediate 20 times increase in the mean plasma glucose concentration PGI, over the pre60 and pre10. The peak plasma insulin concentration occurred at 30 min PGI. The mean plasma glucose and insulin concentrations remained above pre-administration levels until 420 min PGI (p < 0.05). However, the mean plasma glucagon concentrations were different only at 1 and 5 min PGI sampling times. The curve of the IGR for group I showed an initial decrease at 1 min PGI, and fluctuated from 10.18 to 25.55 for the remainder of the sampling period. The correlation analysis showed that the mean plasma glucose concentration was positively correlated with insulin level (r = 0.73, p < 0.005), and significantly negatively correlated with mean plasma glucagon (r = -0.58, p < 0.05). The mean plasma insulin level did not show significant correlation with the glucagon (r = 0.06, p > 0.05). CONCLUSION: The hyperglycemia, high insulin, and protracted glucose and insulin curves, the initial decrease in the insulin/glucose ratio indicates that there was an unexpected glucose tolerance to acute intravenous glucose loading in water buffalo compared with other ruminants. The possibly suggested intravenous glucose load in buffaloes is about 5.09-8.28 mmol/l.