Efficacy of local dipyridamole therapy in a porcine model of arteriovenous graft stenosis

Perivascular delivery of antiproliferative drugs has been proposed as an approach to prevent neointimal hyperplasia associated with hemodialysis polytetrafluoroethylene (PTFE) grafts. We examined this approach to deliver dipyridamole in a porcine graft model. PTFE grafts were implanted between the carotid artery and external jugular vein bilaterally in pigs. During the surgery or 1 week post-graft placement, dipyridamole (0.26-52 mg) alone or incorporated in microspheres was mixed with an injectable polymeric gel and applied to the graft-arterial and graft-venous anastomoses on one side, whereas the contralateral control graft received no treatment. Three or four weeks after operation, the grafts and adjacent vessels were explanted en bloc and cross-sections of the anastomoses were examined histologically. The degree of neointimal hyperplasia was quantified by planimetry. In separate experiments, dipyridamole was extracted from the explanted tissues and assayed by spectrofluorometry. The normalized median hyperplasia areas of the treated and control graft-venous anastomoses were 0.45 (25th-75th percentile, 0.30-0.86) and 0.24 (0.21-0.30), respectively (N=7; P=0.08). The median hyperplasia areas of the treated and control graft-arterial anastomoses were 0.12 (0.07-0.39) and 0.11 (0.09-0.13), respectively (N=7; P=0.31). The dipyridamole levels in the vascular walls around the anastomoses were at or above the in vitro inhibitory concentrations for approximately 3 weeks. These results suggest that the local perivascular sustained delivery of dipyridamole, even at high dosages, was ineffective in inhibiting neointimal hyperplasia associated with PTFE grafts in a porcine model.

Unrelated donor bone marrow transplantation for β-thalassemia major: an experience from China

Although related bone marrow transplantation (BMT) is effective for thalassemia, less than 30% of patients have sibling donors. Here, we report unrelated BMT in nine thalassemic children using a high-resolution HLA typing technique to identify donors. HLA mismatches between donors and recipients were 0, 1 and 2 in 2, 5 and 2 cases, respectively. The results showed that white blood cells, platelets and hemoglobin all returned to normal at various time points, and blood transfusion was eliminated from 13 to 62 days after transplantation. Full engraftment was achieved in eight patients while ABO blood types were replaced with that of donors in five of the six ABO mismatched recipients. Acute skin GVHD was found in seven patients and acute liver GVHD in one. One patient with acute intestinal GVHD eventually developed chronic GVHD. One patient died of pulmonary hemorrhage in spite of having a fully functional graft. We conclude that this is the first successful application of unrelated BMT for thalassemia major in Chinese people and that the results will certainly expand donor resources and greatly enhance the survival and quality of life of thalassemic patients.

Mu-opioid-mediated inhibition of glutamate synaptic transmission in rat central amygdala neurons

The central nucleus of the amygdala (CeA) plays an important role both in stimulus-reward learning for the reinforcing effects of drugs of abuse and in environmental condition-induced analgesia. Both of these two CeA functions involve the opioid system within the CeA. However, the pharmacological profiles of its opioid receptor system have not been fully studied and the synaptic actions of opioid receptors in the CeA are largely unknown. In this study with whole-cell voltage-clamp recordings in brain slices in vitro, we examined actions of opioid agonists on glutamate-mediated excitatory postsynaptic currents (EPSCs) in CeA neurons. Opioid peptide methionine-enkephalin (ME; 10 microM) produced a significant inhibition (38%) in the amplitude of evoked EPSCs, an action mimicked by the mu-opioid receptor agonist [D-Ala(2),N-MePhe(4),Gly-ol(5)]-enkephalin (DAMGO; 1 microM, 44%). Both effects of ME and DAMGO were abolished by the mu receptor antagonist CTAP (1 microM), suggesting a mu receptor-mediated effect. Neither delta-opioid receptor agonist [D-Pen(2),D-Pen(5)]-enkephalin (1 microM) nor kappa-opioid receptor agonist U69593 (300 nM) had any effect on the glutamate EPSC. ME significantly increased the paired-pulse ratio of the evoked EPSCs and decreased the frequency of miniature EPSCs without altering the amplitude of miniature EPSCs. Furthermore, the mu-opioid inhibition of the EPSC was blocked by 4-aminopyridine (4AP; 100 microM), a voltage-dependent potassium channel blocker, and by phospholipase A(2) inhibitors AACOCF(3) (10 microM) and quinacrine (10 microM). These results indicate that only the mu-opioid receptor is functionally present on presynaptic glutamatergic terminals in normal CeA neurons, and its activation reduces the probability of glutamate release through a signaling pathway involving phospholipase A(2) and the presynaptic, 4AP-sensitive potassium channel. This study provides evidence for the presynaptic regulation of glutamate synaptic transmission by mu-opioid receptors in CeA neurons.

Soil resource availability impacts microbial response to organic carbon and inorganic nitrogen inputs

Impacts of newly added organic carbon(C) and inorganic nitrogen (N) on the microbial utilization of soil organic matter are important in determining the future C balance of terrestrial ecosystems. We examined microbial responses to cellulose and ammonium nitrate additions in three soils with very different C and N availability. These soils included an organic soil (14.2% total organic C, with extremely high extractable N and low labile C), a forest soil (4.7% total organic C, with high labile C and extremely low extractable N), and a grassland soil (1.6% total organic C, with low extractable N and labile C). While cellulose addition alone significantly enhanced microbial respiration and biomass C and N in the organic and grassland soils, it accelerated only the microbial respiration in the highly-N limited forest soil. These results indicated that when N was not limited, C addition enhanced soil respiration by stimulating both microbial growth and their metabolic activity. New C inputs lead to elevated C release in all three soils, and the magnitude of the enhancement was higher in the organic and grassland soils than the forest soil. The addition of cellulose plus N to the forest and grassland soils initially increased the microbial biomass and respiration rates, but decreased the rates as time progressed. Compared to cellulose addition alone, cellulose plus N additions increased the total C-released in the grassland soil, but not in the forest soil. The enhancement of total C-released induced by C and N addition was less than 50% of the added-C in the forest soil after 96 d of incubation, in contrast to 87.5% and 89.0% in the organic and grassland soils. These results indicate that indigenous soil C and N availability substantially impacts the allocation of organic C for microbial biomass growth and/or respiration, potentially regulating the turnover rates of the new organic C inputs.

Reduction of neural and vascular damage by transplantation of VEGF-secreting neural stem cells after cerebral ischemia

We determined the role of VEGF-transfected neural stem cells (NSCs) transplantation in rat brain subjected to ischemia. Fetal NSCs were cultured from E14 days SD rats and transfected with VEGF121 gene by using lipofectamine technique. Temporary middle cerebral artery occlusion (tMCAO) models were established and randomly divided into 1: control group, 2: PBS transplantation group, 3: NSCs transplantation group and 4: VEGF-secreting NSCs transplantation group. Grafts were transplanted into the penumbra zones 3 days after tMCAO model established. Neurological Severity Score (NSS) was checked in all groups 2-12 weeks after transplantation. By using immunofluorescent staining, VEGF expression of transplanted cells, differentiation and migration of transplanted NSCs after transplantation were detected. VEGF gene-transfected neural stem cells expressed gene products during the first 2 weeks. NSS in this group was significantly lower compared with that in other 3 groups 12 weeks after transplantation. VEGF gene-transfected NSCs migrated and expressed VEGF in hosts' brains, some of them differentiated to neurons 12 weeks after transplantation. VEGF-transfected NSCs expressed gene products during the early time after transplantation, which reduce brain injury through protecting the vascular system against ischemic attack.

Synaptic properties and postsynaptic opioid effects in rat central amygdala neurons

An important output of amygdaloid nuclei, the central nucleus of the amygdala (CeA) not only mediates negative emotional behaviors, but also participates in the stimulus-reward learning and expression of motivational aspects of many drugs of abuse, and links environmentally stressful conditions such as fear to endogenous pain-inhibiting mechanisms. The endogenous opioid system in the CeA is crucial for both reward behaviors and environmental stress-induced analgesia. In this study using whole-cell voltage-clamp recordings, we investigated synaptic inputs and the postsynaptic effects of opioid agonists in CeA neurons. We found that synaptic inputs evoked within the CeA were mediated by both glutamate and GABA, but those evoked from the basolateral amygdala were primarily glutamatergic. Based on membrane properties, three types of cells were characterized. Type A neurons had no spike accommodation while type B neurons displayed characteristic accommodating response. Type A neurons were further classified as either A1 or A2, based on differences in resting membrane potential and the amplitude of after-hyperpolarizing potential. micro-Opioid receptor agonists hyperpolarized a subpopulation of CeA neurons, of which the vast majority was type A1. This micro agonist-induced hyperpolarization was mediated by the opening of inwardly rectifying potassium channels. In contrast, the kappa-opioid receptor agonist hyperpolarized only type B neurons. These results illustrate three types of CeA neurons with distinctive membrane properties and differential responses to opioid agonists. They may represent functionally distinct CeA cell groups for the integration and execution of CeA outputs in the aforementioned CeA functions.

Antiviral property and mode of action of a sulphated polysaccharide from Sargassum patens against herpes simplex virus type 2

A sulphated polysaccharide (SP2) was isolated from the brown alga Sargassum patens. SP2 inhibited the replication of herpes simplex virus type 2 (HSV-2) dose-dependently by 38.5-96.1% of the control level, after incubations with 0.78-12.5 microg/ml of the polysaccharide. SP2 exhibited extracellular virucidal activity only in high concentrations (>/=12.5 microg/ml) but significantly inhibited the virus attachment to its host cells by 45.1%, at concentration as low as 1 microg/ml. All the results from this study suggested that the antiviral mode of action of SP2 could be ascribed to the inhibition of virus adsorption, which is different from that of the current drug of choice acyclovir.

DNA immunization of mice with a plasmid encoding Neisseria gonorrhea PorB protein by intramuscular injection and epidermal particle bombardment

Immunogenicity of a DNA vaccine encoding PorB from Neisseria gonorrhoeae strain FA1090 was analyzed in BALB/C mice immunized by intramuscular needle injection or epidermal gene gun bombardment. Both delivery routes generated measurable specific antibodies although the gene gun response was slower. Antibody isotypes were indicative of Th2 activation following gene gun immunization and of Th1 activation following intramuscular injection. In both immunization protocols, boosting with either renatured recombinant (rr) PorB protein or PorB expressed from Venezuelan equine encephalitis virus replicon particles (VRPs) significantly increased anti-PorB antibody levels. Boosting with rrPorB protein had little effect on antibody isotypes, while boosting with VRPs expressing PorB-enhanced a Th1 type response. Whole cell binding experiments showed that a portion of the antibodies recognized the surface of the homologous N. gonorrhoeae strain. Serum from groups with high antibody levels showed some opsonization of the homologous strain using human neutrophils. These results showed the potential of DNA vaccination for the purpose of priming an antibody response against PorB of N. gonorrhoeae. When combined with a protein or VRP boost, DNA priming resulted in high-titer and long-lasting responses. Based on different prime-boost protocols, we could polarize immune responses to predominantly Th1 or Th2, which should enable future studies of the types of immune responses that are protective in mouse models of gonorrhea.

Morphine enhances nitric oxide release in the mammalian gastrointestinal tract via the micro(3) opiate receptor subtype: a hormonal role for endogenous morphine

Studies from our laboratory have revealed a novel micro opiate receptor, micro(3), which is expressed in both human vascular tissues and leukocytes. The micro(3) receptor is selective for opiate alkaloids, insensitive to opioid peptides and is coupled to constitutive nitric oxide (cNO) release. We now identify the micro(3) receptor characteristics in mammalian gut tissues. It appears that the various regions of the mouse gut release low levels of NO (0.02 to 4.6 nM ) in a pulsatile manner. We demonstrate that morphine stimulates cNO release (peak level 17 nM) in the mouse stomach, small intestine and large intestine in a naloxone and L-NAME antagonizable manner. Opioid peptides do not exhibit cNO-stimulating capabilities in these tissues. Taken together, we surmise morphine acts as a hormone to limit gut activity via micro(3) coupled to NO release since micro opiate receptors are found in the gut and endogenous morphine is not but is found in blood.

Effects of L-THP on Ca2+ overload of cultured rat cardiomyocytes during hypoxia and reoxygenation

The effects of L-tetrahydropalmatine (L-THP) on the cultured rat cardiomyocytes during hypoxia and reoxygenation and the mechanism of L-THP treating reperfusion-arrythmias were studied. The concentration of intracellular free calcium ([Ca2+]i) of single cultured ventricular myocyte was determined by using EPC-9 light-electricity measurement system. It was found that L-THP (100 mumol/L) could reduce the [Ca2+]i augmentation in single cultured ventricular myocyte during hypoxia and reoxygenation. Verapamil (10 mumol/L) had the similar effect. It was concluded that L-THP could inhibit the Ca2+ overload of cultured rat cardiomyocytes during hypoxia and reoxygenation.

Nicotine inhibits voltage-dependent sodium channels and sensitizes vanilloid receptors

Nicotine is an alkaloid that is used by large numbers of people. When taken into the body, it produces a myriad of physiological actions that occur primarily through the activation of neuronal nicotinic acetylcholine receptors (nAChRs). We have explored its ability to modulate TRPV1 receptors and voltage-gated sodium channels. The reason for investigating nicotine's effect on sodium channels is to obtain a better understanding of its anti-nociceptive properties. The reasons for investigating its effects on capsaicin-activated TRPV1 channels are to understand how it may modulate this channel that is involved in pain, inflammation, and gustatory physiology. Whole cell patch-clamp recordings from rat trigeminal ganglion (TG) nociceptors revealed that nicotine exhibited anesthetic properties by decreasing the number of evoked action potentials and by inhibiting tetrodotoxin-resistant sodium currents. This anesthetic property can be produced without the necessity of activating nAChRs. Nicotine also modulates TRPV1 receptors inducing a several-fold increase in capsaicin-activated currents in both TG neurons and in cells with heterologously expressed TRPV1 receptors. This sensitizing effect does not require the activation of nAChRs. Nicotine did not alter the threshold temperature (approximately 41 degrees C) of heat-activated currents in TG neurons that were attributed to arise from the activation of TRPV1 receptors. In this regard, its effect on TRPV1 receptors differs from those of ethanol that has been shown to increase the capsaicin-activated current but decrease the threshold temperature. These studies document several new effects of nicotine on channels involved in nociception and indicate how they may impact physiological processes involving pain and gustation.

[Evaluation of immunochromatographic test in the diagnosis of Plasmodium falciparum and Plasmodium vivax]

AIM

To evaluate the effectiveness of immunochromatographic test(ICT) in detecting Plasmodium falciparum and Plasmodium vivax in malaria endemic areas.

METHODS

ICT was used to detect P. falciparum and P. vivax among patients with fever in the outpatient clinics by comparason with thick blood smear method.

RESULTS

The sensitivity of ICT to detect P. falciparum and P. vivax was 96.7% and 90.4%, respectively. The specificity of ICT was 98.6%, and the coincidence rate was 94.7%. There is no cross reaction between P. falciparum and P. vivax.

CONCLUSION

ICT could detect P. falciparum and P. vivax simutaneously, being more rapid and simple than blood smear method.

Involvement of the entorhinal cortex in the stress response to immobilization, but not to insulin-induced hypoglycaemia

Although the involvement of the limbic system in the neuroendocrine responses to some stressors has been documented, the specific role of the entorhinal cortex has not been elucidated. In this study, we investigated the involvement of the entorhinal cortex in stress responses. Fos immunoreactivity, a widely used marker for neuronal activation, was detected in the entorhinal cortex of rats subjected to immobilization stress, whereas no marked staining was observed in the entorhinal cortex of the control and insulin-induced hypoglycaemia groups. Lesion of the entorhinal cortex produced by ibotenic acid significantly attenuated the adrenocorticotropic hormone (ACTH) release evoked by immobilization; however, no significant change in ACTH release was observed in insulin-induced hypoglycaemia. No significant difference between entorhinal-lesioned rats and control rats was observed in blood glucose concentrations when subjected to either immobilization or to insulin-induced hypoglycaemia. Together, these results indicate that the entorhinal cortex is closely involved in the stress response to immobilization but not to insulin-induced hypoglycaemia.

[Effects of phenylalanine, sucrose and mannitol on the growth and production of taxol, baccatin III and 10-deacetylbaccatin III in suspension cells of Taxus media]

The effects of phenylalanine, sucrose and mannitol on the cell growth and the production of taxol, baccatin III and 10-deacetylbaccatin III in the suspension cells of Taxus media were studied. The results showed that phenylalanine 1.0 mmol.L-1 or 2.0 mmol.L-1 initially added into the medium, and sucrose 73.0 mmol.L-1 and mannitol 173.3 mmol.L-1 added into the medium at the 28th d of culture strongly promoted the cell growth and the formation of the three taxanes in the suspension cells. Compared with those of the control, the cell biomass of the treatments supplemented with phenylalanine and added with sucrose and mannitol at the 28th d of culture increased by 0.6-0.8-fold, taxol yield by 9-10-fold, baccatin III yield by 2.5-3.0-fold, and 10-deacetylbaccatin III yield by 7-fold. Addition of sucrose 73.0 mmol.L-1 at the 28th d of culture significantly promoted the cell growth, but showed little effect on the contents of the three taxanes in the suspension cultures.

[Experimental study on induction of apoptosis of leukemic cells by Boswellia carterii Birdw extractive]

The purpose of the study was to investigate the apoptosis of leukemic cells induced by Boswellia Carterii Birdw(BCB). The target leukemia cell line HL60 and bone marrow leukemic cells from 30 acute non-lymphocytic leukemic(ANLL) patients (3 M1 11 M2a 10 M3 1 M4a 5 M5b) were studied. Apoptosis was detected by morphological observation, DNA electrophoresis, percentage of DNA fragmentation test and flow cytometric cell cycle analysis. It is concluded that BCB can induce apoptosis in ANLL cells and HL60 cells.

[Diagnosis of Falciparum malaria by immunochromatographic test]

AIM

To evaluate the applicability of rapid immunochromatographic test(ICT) for diagnosing falciparum malaria in outpatient clinics in endemic area.

METHODS

With thick blood smear method as control, ICT was used for the detection of P. falciparum.

RESULTS

The sensitivity and specificity of ICT in detecting P. falciparum was 94.7% and 90.3%, respectively. No cross-reaction with P. vivax was found (P > 0.05).

CONCLUSION

ICT is much more rapid and simple than thick blood smear method for the diagnosis of falciparum malaria, and can be applied in the outpatient clinics in endemic area.

Proteomic analysis of nipple aspirate fluid to detect biologic markers of breast cancer

The early detection of breast cancer is the best means to minimise disease-related mortality. Current screening techniques have limited sensitivity and specificity. Breast nipple aspirate fluid can be obtained noninvasively and contains proteins secreted from ductal and lobular epithelia. Nipple aspirate fluid proteins are breast specific and generally more concentrated than corresponding blood levels. Proteomic analysis of 1 microl of diluted nipple aspirate fluid over a 5-40 kDa range from 20 subjects with breast cancer and 13 with nondiseased breasts identified five differentially expressed proteins. The most sensitive and specific proteins were 6500 and 15 940 Da, found in 75-84% of samples from women with cancer but in only 0-9% of samples from normal women. These findings suggest that (1) differential expression of nipple aspirate fluid proteins exists between women with normal and diseased breasts, and (2) analysis of these proteins may predict the presence of breast cancer.