Multimodal small-molecule screening for human prion protein binders.

Prion disease is a rapidly progressive neurodegenerative disorder caused by misfolding and aggregation of the prion protein (PrP), and there are currently no therapeutic options. PrP ligands could theoretically antagonize prion formation by protecting the native protein from misfolding or by targeting it for degradation, but no validated small-molecule binders have been discovered to date. We deployed a variety of screening methods in an effort to discover binders of PrP, including 19F-observed and saturation transfer difference (STD) NMR spectroscopy, differential scanning fluorimetry (DSF), DNA-encoded library selection, and in silico screening. A single benzimidazole compound was confirmed in concentration-response, but affinity was very weak (Kd > 1 mm), and it could not be advanced further. The exceptionally low hit rate observed here suggests that PrP is a difficult target for small-molecule binders. Whereas orthogonal binder discovery methods could yield high-affinity compounds, non-small-molecule modalities may offer independent paths forward against prion disease.

Curcumin improves insulin resistance in skeletal muscle of rats.

BACKGROUND AND AIMS: Curcumin has been reported to lower plasma lipids and glucose in diabetic rats, and to decrease body weight in obese rats, which may partly be due to increased fatty acid oxidation and utilization in skeletal muscle. METHODS AND RESULTS: Diabetic rats induced by high-fat diet plus streptozotocin (STZ, 30 mg/kg BW) were fed a diet containing 50, 150, or 250 mg/kg BW curcumin for 7 wk. Curcumin dose-dependently decreased plasma lipids and glucose and the dose 150 mg/kg BW appeared to be adequate to produce a significant effect. Curcumin supplementation reduced glucose and insulin tolerance measured as areas under the curve. L6 myotubes were treated with palmitate (0.25 mmol/L) in the presence of different levels of curcumin for 24 h in our in vitro experiment. Curcumin at 10 µmol/L was adequate to cause a significant increase in 2-deoxy-[(3)H]d-glucose uptake by L6 myotubes. Curcumin up-regulated expression of phosphorylated AMP-activated protein kinase (AMPK), CD36, and carnitine palmitoyl transferase 1, but down-regulated expression of pyruvate dehydrogenase 4 and phosphorylated glycogen synthase (GS) in both in vivo and in vitro studies. Moreover, curcumin increased phosphorylated acetyl COA carboxylase in L6 myotubes. The effects of curcumin on these enzymes except for GS were suppressed by AMPK inhibitor, Compound C. LKB1, an upstream kinase of AMPK, was activated by curcumin and inhibited by radicicol, an LKB1 destabilizer. CONCLUSION: Curcumin improves muscular insulin resistance by increasing oxidation of fatty acid and glucose, which is, at least in part, mediated through LKB1-AMPK pathway.

The HIV related risks among men having sex with men in rural Yunnan, China: a qualitative study.

OBJECTIVES: To explore the characteristics and issues specific to HIV related risk behaviours among men who have sex with men (MSM) in rural China. METHOD: Qualitative study using semistructured in-depth interviews in Dali prefecture, Yunnan. 24 informants recruited through a local MSM network, snowballing and by word of mouth. The main outcome measures were themes identified as increased exposures and risks to HIV. RESULTS: Risk behaviour, social stigma, one child policy and concepts of traditional Chinese medicine (TCM) had significant roles in the spread of HIV in rural China. Many MSM lead a life with double identities in China and condom use was found to be variable with attempts to "rationalise" the risky behaviour being its major determining factor. Health seeking behaviours of genitourinary problems were infrequent and illogical, which were further held back by the existing healthcare system and lack of sensitivity expressed by the health professionals. CONCLUSIONS: Clear education messages to the general public while raising awareness among health professionals of the health risks and needs in MSM are essential in the prevention of the current HIV epidemic.

alpha-Glycosidase inhibitory activity of hexagalloylglucose from the galls of Quercus infectoria.

Hexagalloylglucose (3-O-digalloyl-1,2,4,6-tetra-O-galloyl-beta-D- glucose), which was isolated from the methanol extract of the galls of Quercus infectoria, significantly inhibited alpha-glycosidases such as sucrase, maltase and isomaltase. Its inhibitory activity was comparable to acarbose being used as a hypoglycemic agent, while the inhibitory activity on alpha-amylase was approximately 10 times lower than that of acarbose. The results indicate that, when compared to acarbose, hexagalloylglucose might reduce the side effects by reducing inhibition of alpha-amylase.

[Effect of anticancer polypeptide from Buthus Martensii venom on immune function in the H22-bearing mice].

OBJECTIVE: To observe the effect of anticancer polypeptide from Buthus Martensii Venom (APBMV) on Immune function in the H22-bearing mice. METHODS: The MTT colorimetric method, homolysin assay, lymphocyte transformation test, delayed hypersensitivity assay and WBC-count of peripheral blood were used in this study. RESULTS: APBMV could obviously augment NK activity, promote proliferation of lymphocytes induced by Con A, potentiate the response of DTH induced by DNCB, antagonize the decrease of WBC in peripheral blood induced by 5-Fu in the H22-bearing mice. CONCLUSION: APBMV can obviously increase immune function in the H22-bearing mice and antagonize hypoimmunity immunodeficiency or immunodeficiency induced by chemotherapy or the tumor.

The inhibitory effect of extracts from Fructus lycii and Rhizoma polygonati on in vitro DNA breakage by alternariol.

Alternariol caused DNA single-strand breakage. Conversion of the closed circular double-stranded supercoiled DNA (pBR 322) to the nicked circular form and linear form was used to investigate the effect of extracts of some Chinese medical herbs on DNA nicking induced by alternariol. Some substances in the extracts of Rhizoma polygonati (RP) and Fructus lycii (FL) were shown to protect DNA from the attack by alternariol. Some substance in the RP may bind to plasmid DNA, and this binding reduces the electrophoretic mobility of DNA. These results indicate that substances from FL and RP may be used as DNA protectors. It is possible that they play an important role in preventing cancer.

[Relationship between acupuncture analgesia and neurotransmitters in nucleus raphe magnus].

Nucleus Raphe Magnus (NRM) is a complex cell group. 5-HT, SP and ENK neurons in the NRM were identified by immunocytochemistry method. The afferent fibers containing 5-HT, SP, M-ENK, L-ENK, B-EP and SRIF were observed in NRM, the efferent fibers containing 5-HT, SP, ENK and TRH from NRM to spinal cord were studied. Two neurotransmitters (such as 5-HT with SP, ENK or TRH) were found in same neuron, fiber or vesicle. The neurons and axo-dendritic synapses of the NRM were analysed during Electroacupuncture (EA). The NRM increased their synaptic releases and the neurons were in active functional state during EA "Zusnanli". Studies show that NRM is one of important positions in EA analgesia.

[Electroacupuncture promotes the regeneration of different fibers in rat's tibial nerve].

METHODS: 45 rats (150-200g) were divided into 9 groups. The experimental steps as follows: (1) injured left tibial nerve (group 1-8) and sham operation (group 9); (2) three days after operation, group 1, 3, 5 and 7 were stimulated with electro-acupuncture (EA) in Huantiao (+) and Sanyinjiao (-); (3) according to different survival time (group 1, 2/10 days, group 3, 4/15 days, group 5, 6/20 days, group 7, 8, 9/25 days), 48h before sacrifice, the left femoral nerve was cut, HRP was injected into the hypodermis of paw pad and gastrocnemius; (4) observe HRP labelled cells in the lumber sympathetic ganglia, ganglion spinale (L4-6) and cornu ventrale of spinal cord (L3-S3). RESULTS: EA 7 days, 2-5 labeled cells were only found in ganglion spinales of group 1; EA for 12 days, the more HRP labeled cells were observed in the lumber sympathetic ganglions (mean = 2.6), ganglion spinales (mean = 4.8) and cornu ventrale (mean = 6) of group 3 as compared with group 4 (P < 0.05); 25 days after operation, the quantity of labeled cells in group 8 was close to group 9. CONCLUSION: (1) EA promote the regeneration of three or more kinds of fibers in tibial nerve; (2) The regeneration velocity of sensory fibers was faster than sympathetic and somatic efferent fibers.

[Research on serotonergic neurons in lateral raphe nucleus of rat with intracellular injection HRP technique].

UNLABELLED: This experiment was carried out on 35 rats with stereotaxic apparatus following a new coordinate which was designed by ourselves. The microelectrode was pushed into the lateral dorsal raphe nucleus (LDR) under direct vision. The neurons with regular rhythm and slow firing rate were searched by intracellular recording, then the singular cell in LDR was filled with HRP by intracellular iontophoresis. RESULTS: 7 HRP labelling neurons with serotoninergic firing characteristics were observed in LDR. The labelling dendrites were found in neighboured structure (periaqueductal gray, laterodorsal tegmental nucleus, dorsal tegmental nucleus, 4th ventricle). This work demonstrated that LDR plays some role in acupuncture analgesia.

[Studies on the relationship between acupuncture analgesia and testosterone or dihydrotestosterone in blood plasma].

UNLABELLED: 55 rats (Wistar, Male, 250-350 g) were divided into 4 groups: (1) BTA (bilateral testectomy + adrenalectomy) group, (2) BT (bilateral testectomy) group, (3) BA (bilateral adrenalectomy) group, (4) SO (sham operation) group. EA was applied to bilateral "Tsusanli" points of each animal at 72 h. after operation. The potassium iontophoretic colorimetry was used to determine the pain threshold of rats, radioimmunoassay was used to measure the contents of T and DHT in femoral vein blood. T, DHT and the pain threshold of each animal were measured before operation, at 72 h, after operation and after EA, but for the SO group the measurement was done once at 72 h. after im testosterone phenylacetate. RESULTS: The content of T in BTA and BT groups were decreased. significantly at 72 h. after operation, but the changes of the pain threshold were similar to BA and SO groups. After EA the content of T in BT and SO groups were raised significantly (P less than 0.01), but in BT group raised slightly (P greater than 0.05). It was found in all animals that the content of DHT and the pain threshold were significantly elevated at 45 min after EA. No effect upon the pain threshold and EA analgesia was observed in SO group after im testosterone phenylacetate. CONCLUSION: T (from testes and adrenal) and DHT rose markedly after EA. Increasing T and DHT or decreasing T in plasma had no effect upon the pain threshold and EA analgesia. It is suggested that T and DHT in plasma may not play a role in the EA analgesia, in the other hand, EA may be used for improving the hypogonadal condition.