Swine intestine antimicrobial peptides inhibit infectious bronchitis virus infectivity in chick embryos

Infectious bronchitis virus (IBV), the causative agent of infectious bronchitis, results in respiratory disease, nephritis, and poor egg production and quality in chicken. Antimicrobial peptides possess potent antimicrobial activities and are regarded as promising therapeutic alternatives in the fight against microorganisms. To assess the in vitro antiviral activity of swine intestine antimicrobial peptides (SIAMP) against IBV, 45 chick embryos were randomly assigned into 3 groups, 15 for each group. Embryos in group 1 were inoculated with IBV. Group 2 was inoculated with SIAMP-IBV intermixture. Group 3 was used as a control and inoculated with sterile PBS. Allantoic fluid was collected for hemagglutination titer assay. In addition, weight gain, mortality, and pathological changes for each group were recorded. The results showed that no distinct pathological changes were found in chick embryos after they were inoculated with SIAMP-IBV intermixture and the mortality was reduced remarkably compared with the IBV-infected group. Weight gain of embryos in the SIAMP-IBV intermixture group was significantly higher than the IBV-infected embryos (P < 0.01), which was also higher than the control group (P < 0.05). Furthermore, the hemagglutination titer in the SIAMP-IBV group was significantly lower than that in the IBV-infected group (P < 0.01). These results indicated that SIAMP can inhibit virus replication and reduce tissue injury caused by IBV.

Effect of high-dose methylprednisolone treatment on Th17 cells in patients with multiple sclerosis in relapse

OBJECTIVES

Growing evidences have suggested that Th17 cells are involved in the pathogenic mechanisms of multiple sclerosis (MS). Treatment with high-dose intravenous methylprednisolone (IVMP) has beneficial effects on functional recovery in patients with MS during relapse. The present study was designed to analyze the influences of IVMP on Th17 cells in patients with MS after a 5-day high-dose IVMP treatment.

MATERIALS AND METHODS

Th17 cell count and the production of IL-17 in peripheral blood mononuclear cells (PBMCs) were measured using flow cytometry and ELISA respectively. Quantitative real-time PCR was performed to analyze the mRNA expression of Th17 cell-related factors (IL-17, RORc and IL-23R) in PBMCs.

RESULTS

A significant reduction in IL-17 production and Th17 cells count in PBMCs was found in patients with MS after IVMP treatment. Moreover, the expression of IL-17, IL-23R and RORc mRNA decreased significantly after IVMP treatment.

CONCLUSIONS

Treatment with methylprednisolone has a suppressive effect on Th17 cells and may be related to its clinical efficiency.

TRPC channel-mediated neuroprotection by PDGF involves Pyk2/ERK/CREB pathway

Platelet-derived growth factor-BB (PDGF) has been reported to provide tropic support for neurons in the central nervous system. The protective role of PDGF on dopaminergic neurons, especially in the context of HIV-associated dementia (HAD), however, remains largely unknown. Here, we show that exogenous PDGF was neuroprotective against toxicity induced by HIV-1 Tat in primary midbrain neurons. Furthermore, we report the involvement of transient receptor potential canonical (TRPC) channels in PDGF-mediated neuroprotection. TRPC channels are Ca(2+)-permeable, nonselective cation channels with a variety of physiological functions. Blocking TRPC channels with either a blocker or short-interfering RNAs (specific for TRPC 5 and 6) in primary neurons resulted in suppression of both PDGF-mediated neuroprotection as well as elevations in intracellular Ca(2+). PDGF-mediated neuroprotection involved parallel but distinct ERK/CREB and PI3K/Akt pathways. TRPC channel blocking also resulted in suppression of PDGF-induced Pyk2/ERK/CREB activation, but not Akt activation. Relevance of these findings in vivo was further corroborated by intrastriatal injections of PDGF and HIV-1 Tat in mice. Administration of PDGF was able to rescue the dopaminergic neurons in the substantia nigra from Tat-induced neurotoxicity. This effect was attenuated by pre-treatment of mice with the TRP blocker, thus underscoring the novel role of TRPC channels in the neuroprotection mediated by PDGF.

EGFR-PLCgamma1 signaling mediates high glucose-induced PKCbeta1-Akt activation and collagen I upregulation in mesangial cells

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We have recently shown that epidermal growth factor receptor (EGFR) transactivation mediates high glucose (HG)-induced collagen I upregulation through PI3K-PKCbeta1-Akt signaling in mesangial cells (MC). Phospholipase Cgamma1 (PLCgamma1) interacts with activated growth factor receptors and activates classic PKC isoforms. We thus studied its role in HG-induced collagen I upregulation in MC. Primary rat MC were treated with HG (30 mM) or mannitol as osmotic control. Protein kinase activation was assessed by Western blotting and collagen I upregulation by Northern blotting. Diabetes was induced in rats by streptozotocin. HG treatment for 1 h led to PLCgamma1 membrane translocation and Y783 phosphorylation, both indicative of its activation. Mannitol was without effect. PLCgamma1 Y783 phosphorylation was also seen in cortex and glomeruli of diabetic rats. HG induced a physical association between EGFR and PLCgamma1 as identified by coimmunoprecipitation. PLCgamma1 activation required EGFR kinase activity since it was prevented by the EGFR inhibitor AG1478 or overexpression of kinase-inactive EGFR (K721A). Phosphoinositide-3-OH kinase inhibition also prevented PLCgamma1 activation. HG-induced Akt S473 phosphorylation, effected by PKCbeta1, was inhibited by the PLCgamma inhibitor U73122. PLCgamma1 inhibition or downregulation by small interference RNA also prevented HG-induced collagen I upregulation. Our results indicate that EGFR-PLCgamma1 signaling mediates HG-induced PKCbeta1-Akt activation and subsequent collagen I upregulation in MC. Inhibition of EGFR or PLCgamma1 may provide attractive therapeutic targets for the treatment of diabetic nephropathy.

Alendronate is effective to treat bone loss in renal transplantation recipients

Bone loss is a common complication among renal transplant patients. Some studies have shown that alendronate may be effective to treat bone loss in these patients. In this study, we have reported our experience with administration of alendronate to treat bone loss in renal transplanted patients.

METHODS

The 46 kidney transplant recipients with bone loss were randomly divided into 2 groups: group I was treated with calcium and calcitriol, and group II with calcium, calcitriol, and alendronate. We examined bone mineral density (BMD) and biochemical indicators of both groups. All patients received cyclosporine and prednisone treatment.

RESULTS

There was no significant difference in age, body mass index, gender, immunosuppression, time since transplantation, 25(OH)D(3), or intact parathyroid hormone levels at study commencement. The BMD of the femoral neck was significantly increased (P < .05), and the serum type I collagen-cross-linked N telopeptide (NTx) dramatically (P < .05) decreased in posttransplantation group II recipients treated with calcium, calcitriol, and alendronate. There were also significant differences in BMD and serum NTx between recipients treated with versus without alendronate (P < .05).

CONCLUSION

At least in the short term, alendronate is a effective inhibitor for the treatment of bone loss in renal transplantation patients.

A novel lipopeptide produced by a Pacific Ocean deep-sea bacterium, Rhodococcus sp. TW53

AIMS

Our goal was to find a novel, biosurfactant-producing bacterium from Pacific Ocean deep-sea sediments.

METHODS AND RESULTS

An oil-degrading biosurfactant-producing bacterium TW53 was obtained from deep-sea sediment, and was identified through 16S rDNA analysis as belonging to the genus Rhodococcus. It lowered the surface tension of its culture to 34.4 mN m(-1). Thin layer chromatography (TLC) showed that the crude biosurfactants of TW53 were composed of lipopeptides and free fatty acids (FA). The lipopeptides were purified with column chromatography and then hydrolysed with 6 mol l(-1) HCl. Gas chromatography-mass spectrometry analysis showed that the hydrolyte in the hydrophobic fraction contained five kinds of FA with chain lengths of C(14)-C(19), and C(16)H(32)O(2) was a major component making up 59.18% of the total. However, 3-hydroxyl FA was not found, although it is usually found in lipopeptides. Silica gel TLC revealed that the hydrolyte in the hydrophilic fraction was composed of five kinds of amino acids; consistently, ESI-Q-TOF-MS analysis confirmed the composition results and provided their sequence tentatively as Ala-Ile-Asp-Met-Pro. Furthermore, the yield and CMC (critical micelle concentrations) of purified lipopeptides were examined. The purified product reduced the surface tension of water to 30.7 mN m(-1) with a CMC value of 23.7 mg l(-1). These results suggest that Rhodococcus sp. TW53 produces a novel lipopeptide that we have named rhodofactin.

CONCLUSION

The deep-sea isolate Rhodococcus sp. TW53 was the first reported lipopeptide-producing bacterium of this genus. The lipopeptides had novel chemical compositions.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rhodococcus sp. TW53 has potential in the exploration of new biosurfactants and could be used in bioremediation of marine oil pollution.

Cellular expansion and gene expression in the developing grape (Vitis vinifera L.)

Expression profiles of genes involved in cell wall metabolism and water transport were compared with changes in grape (Vitis vinifera L.) berry growth, basic chemical composition, and the shape, size, and wall thickness of cells within tissues of the berry pericarp. Expression of cell wall-modifying and aquaporin genes in berry pericarp tissues generally followed a bimodal expression profile with high levels of expression coinciding with the two periods of rapid berry growth, stages I and III, and low levels of expression corresponding to the slow-growth period, stage II. Cellular expansion was observed throughout all tissues during stage I, and only mesocarp cellular expansion was observed during stage III. Expansion of only exocarp cells was evident during transition between stages II and III. Cell wall-modifying and aquaporin gene expression profiles followed similar trends in exocarp and mesocarp tissues throughout berry development, with the exception of the up-regulation of pectin methylesterase, pectate lyase, two aquaporin genes (AQ1 and AQ2), and two expansin genes (EXP3 and EXPL) during stage II, which was delayed in the exocarp tissue compared with mesocarp tissue. Exocarp endo-(1-->3)-beta-glucanase and expansin-like gene expression was concurrent with increases in epidermal and hypodermal cell wall thickness. These results indicate a potential role of the grape berry skin in modulating grape berry growth.

Isolated oesophageal cyst connected with the bronchus

We report an unusual case of a patient with an oesophageal cyst connected to the bronchus. A 24-year old male with a two-year history of repeated attacks of chest infection and haemoptysis was found to have a cyst of 4 x 4 cm affecting the anterior and apical segments of the right upper lobe. The cyst was excised in its entirety and the histopathological study of the cyst showed stratified squamous epithelium with submucosal and muscular layer but no cartilage. The pathological diagnosis was an oesophageal cyst. No previous case of isolated oesophageal cyst connected to the bronchus has been reported according to the available literature.

Collagen I induction by high glucose levels is mediated by epidermal growth factor receptor and phosphoinositide 3-kinase/Akt signalling in mesangial cells

AIMS/HYPOTHESIS

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. Recent data have linked the serine/threonine kinase protein kinase B (Akt) to matrix modulation. Here, we studied its role in high glucose-induced collagen elaboration by mesangial cells.

METHODS

Primary rat mesangial cells were treated with high glucose levels (30 mmol/l) or mannitol as osmotic control. Western blots, northern blots, ELISA and immunohistochemistry were used for assessment. Diabetes was induced in rats by streptozotocin.

RESULTS

Phosphorylated Akt at S473 (pAktS473), corresponding to Akt activation, was seen in diabetic glomeruli. In mesangial cells, high glucose levels induced pAktS473 by 20 min. This was sustained to 72 h, while mannitol had no effect. Akt activation by kinase assay and phosphorylation on threonine 308 was also observed. Phosphoinositide 3-kinase (PI3K) inhibitors LY294002 (20 micromol/l) and wortmannin (100 nmol/l) prevented pAktS473. Collagen IA1 transcript and collagen I protein upregulation by high glucose levels were inhibited by PI3K blockade, as was collagen I secretion into the medium (ELISA). Dominant-negative Akt overexpression also inhibited high glucose-induced collagen IA1 transcript and collagen I protein production. Since signalling through the epidermal growth factor receptor (EGFR) can activate PI3K-Akt, we studied its activation by high glucose levels. EGFR was correspondingly activated by 10 min; mannitol had no effect. EGFR activation was also seen in glomeruli from diabetic rats and co-localised with collagen IA1 in diabetic glomeruli. Specific EGFR inhibition (AG1478, 5 micromol/l or dominant-negative EGFR) blocked high glucose-induced pAktS473, phosphorylation on threonine 308 and activation of the EGFR downstream target p44 extracellular signal-regulated kinase (Erk) mitogen-activated protein kinase. Finally, EGFR inhibition also blocked high glucose-induced collagen I upregulation at transcriptional and protein levels.

CONCLUSIONS/INTERPRETATION

We conclude that EGFR-PI3K-Akt signalling mediates high glucose-induced collagen I upregulation in mesangial cells and that this pathway is activated in diabetic glomeruli. Targeting its components may provide a new therapeutic approach to diabetic kidney disease.

An oil-degrading bacterium: Rhodococcus erythropolis strain 3C-9 and its biosurfactants

AIMS

To isolate a biosurfactant-producing bacterium and find new products within its culture.

METHODS AND RESULTS

A biosurfactant-producing bacterium identified as Rhodococcus erythropolis (3C-9 strain) was isolated from seaside soil. When n-hexadecane was supplied as the sole carbon source, two types of biosurfactants (free fatty acids and glycolipids) were detected in the supernatant of the bacterial culture by use of thin layer chromatography (TLC). Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the former consisted of at least 12 free fatty acids of chain lengths from C(9) to C(22); and the latter contained 2 kinds of glycolipids (a glucolipid and a trehalose lipid), which were detected by use of TLC, as well as GC-MS. The hydrophobic moieties of both glycolipids consisted of seven types of straight-chain fatty acids of varying compositions, with chain lengths ranging from C(10) to C(18). It was also noted that biosurfactants of strain 3C-9 were produced in a manner that was growth-related and cannot be synthesized from water-soluble substrates. The effects to enhance the solubility of polycyclic aromatic hydrocarbons and the degradation rate of hexadecane were also tested.

CONCLUSIONS

The biosurfactants produced by strain 3C-9 of R. erythropolis included two kinds of glycolipids, as well as free fatty acids. These biosurfactants were notably different from those of previously reported Rhodococcus species, both in terms of their structure and chemical composition.

SIGNIFICANCE AND IMPACT OF THE STUDY

Strain 3C-9 of R. erythropolis is a competitive candidate for use in oil spill cleanup operations, or in new biosurfactant exploration. The findings in this report show that Rhodococcus is a natural reservoir of new biosurfactants.

Systemic inhibition of tumor growth by soluble Flk-1 gene therapy combined with cisplatin

Soluble Flk-1, a soluble vascular endothelial growth factor (VEGF) receptor, is a potent inhibitor of angiogenesis, which could restrain growth and metastasis of some experimental tumors. However, antiangiogenic agents alone cannot eradicate tumor completely, and should be combined with other therapy to enhance their effects. In this study, we evaluated the antitumor activity of the combination therapy in the immunocompetent BALB/c mice bearing H22 hepatoma and Meth A fibrosarcoma, respectively. Mice were treated with either msFlk-1 i.m. at 100 microg/mouse once every 3 days for four times from day 3 after the tumor cell injection, cisplatin cycled twice (2 mg/kg i.p. on days 4 and 11 after the tumor cell inoculation), or both agents together. Tumor growth and survival time were continually observed. Antiangiogenesis in vivo was determined by CD31 immunohistochemistry. Assessment of apoptotic cells and histological analysis was also conducted in tumor tissues. Our results showed that the combination therapy could evidently improve antitumor efficacy, including tumor growth suppression, mice survival prolongation, tumor cell apoptosis augmentation as well as neovascularization inhibition as compared with controls, without serious adverse effects. Our data suggest that the combination of DDP with msFlk-1 is more effective to suppress tumor growth in mice than either agent alone, and this combination regimen showed its potential for future clinical application.

Combination of MIG (CXCL9) chemokine gene therapy with low-dose cisplatin improves therapeutic efficacy against murine carcinoma

MIG (monokine induced by interferon-gamma) is a CXC chemokine ligand (CXCL9) that can potently inhibit angiogenesis, and displays thymus-dependent antitumor effects. The effectiveness of a treatment combining gene therapy with plasmid-borne MIG (pORF-MIG) and low-dose cisplatin chemotherapy was determined using colon carcinoma (CT26) and Lewis lung carcinoma (LL/2c) murine models. The program was carried out via intramuscular delivery of pORF-MIG at 100 mug/mouse twice a week for 4 weeks, and/or intraperitoneal delivery of cisplatin at 0.6 mg/kg/mouse every 3 days for 48 days. Tumor volume and survival time were evaluated after treatment. CD31 immunohistochemical staining in tumor tissues and alginate capsule models in vivo was used to evaluate angiogenesis. Induction of apoptosis and cytotoxic T-lymphocyte (CTL) activity were also assessed. The combination of pORF-MIG and low-dose cisplatin produced significant antitumor activity, with complete tumor regression in 4/10 of CT26 colon carcinomas and 3/10 of LL/2c lung carcinomas, low vascularity, in alginate capsules, apparently degraded tumor microvessel density, and increased induction of apoptotic and CTL activities compared with either treatment alone. This study suggests that the combination of pORF-MIG plus cisplatin augments the inhibition of angiogenesis and the induction of apoptosis or CTL activity, all of which enhance antitumor activity. These findings may prove useful in further explorations of the application of combinatorial approaches to the treatment of solid tumors.

Clinical application of ipsilateral C7 nerve root transfer for treatment of C5 and C6 avulsion of brachial plexus

We applied a nerve transfer, using the ipsilateral C7 nerve root to treat the C5 and C6 root avulsion of the brachial plexus. Four patients with C5 and C6 preganglionic injury were operated on with this new technique from 1998-2000. Transfer of the spinal accessory nerve to the suprascapular nerve was simultaneously done in 2 these patients. After a follow-up of 1-2.5 years, the muscle strength of elbow flexors recovered to M4 (Lovett) in all cases, shoulder abduction of >90 degrees with external rotation of 30-40 degrees was gained in two cases, and that of 15-45 degrees with no external rotation in the other two cases. No remarkable impairment was found in all C7-innervated muscles except for decrease of muscle power of 1 grade (Lovett) in the short run. This new technique shows promise as an efficacious and safe treatment for C5 and C6 root avulsion of the brachial plexus. However, it should be applied prudently when incomplete injuries of the lower trunk are involved.

Induction of apoptosis by norcantharidin in human colorectal carcinoma cell lines: involvement of the CD95 receptor/ligand

PURPOSE

Cantharidin, a natural toxin, is the active substance of mylabris and has antitumor effects in man. Norcantharidin, the demethylated analogue of cantharidin, has been used in the treatment of patients with primary hepatoma and those with leukopenia in China. The present study was designed to investigate whether norcantharidin exerts cytotoxic activity against colorectal cancer cells by inducing apoptosis and to examine the possible mechanism in the phenomenon.

METHODS

Inhibition of proliferation of norcantharidin on Colo205, HT-29, and SW480 colorectal cancer cells was determined by the trypan blue dye exclusion test. Apoptosis of norcantharidin-treated cells was determined by morphological analysis, agarose gel DNA electrophoresis, and quantitated by flow cytometry after staining with propidium iodide. Cell cycle and the cell surface expression of the CD95/CD95 ligand were evaluated by flow cytometry. Caspase 8-like protease and protein phosphatase 1 and 2A activities were also analyzed.

RESULTS

Treatment with norcantharidin of colorectal cancer cells not only inhibited cell proliferation, but also induced apoptosis. Norcantharidin induced apoptosis mainly in two phases: rapid apoptosis in S-phase cells and delayed apoptosis in G2/M arrested cells. Treatment with norcantharidin resulted in an upregulation of the CD95 receptor and CD95 ligand on the cell surface. Furthermore, stimulation with anti-CD95 monoclonal antibody (mAb) resulted in further induction of apoptosis after treatment with norcantharidin. In addition, the apoptosis-inducing effect of norcantharidin was almost completely inhibited by anti-CD95 ligand mAb. Norcantharidin-treated cells showed the activation of caspase 8. Both zVAD-FMK (a broad range caspase inhibitor) and IETD-FMK (a caspase-8 inhibitor) showed apparent inhibition of the apoptosis-inducing effect. Norcantharidin did not show an inhibitory effect on protein phosphatase.

CONCLUSIONS

These results suggest that norcantharidin triggers apoptosis in colorectal cancer cell lines via the activation of the CD95 receptor/ligand system, and that this agent may be useful for developing new therapeutic regimens for the treatment of colorectal carcinoma.

Single nucleotide polymorphisms in the methylenetetrahydrofolate reductase gene are common in US Caucasian and Hispanic American populations

To investigate the prevalence of the C677T and A1298C single nucleotide polymorphisms (SNPs) in the methylenetetrahydrofolate reductase (MTHFR) gene in Caucasian and Hispanic populations, EDTA-anticoagulated whole blood specimens were collected from a total of 100 random patients, 50 Caucasians and 50 Hispanics of Puerto Rican dissent. The prevalence of the two MTHFR SNPs was determined by polymerase chain reaction (PCR) mediated restriction fragment length polymorphism analysis. In the Caucasian population, homozygosity for the MTHFR A1298C SNP was detected in 4% (2/50) of the individuals tested, while 42% (21/50) were heterozygous for this SNP. Among Hispanics, 4% (2/50) were homozygous and 38% (19/50) heterozygous for the A1298C SNP. Homozygosity for the C677T MTHFR SNP was detected in 16% (8/50) and 10% (5/50) of Caucasians and Hispanics, respectively. In this study, the frequency of the C677T heterozygotes was very high at 56% (28/50) and 52% (26/50) Caucasians and Hispanics, respectively. C677T and A1298C are common SNPs in the MTHFR gene. The high prevalence of these SNPs in both Caucasian and Hispanic populations demonstrates the possibility of compounding effects of these SNPs in the pathogenesis of human diseases. While subgroups of patients may exhibit some clinical phenotype linked to these SNPs, our analysis demonstrates the need for careful interpretation of SNP data in the context of population screening.

Inhibitory effects of gynostemma pentaphyllum on the UV induction of bacteriophage lambda in lysogenic Escherichia coli

Effects of gynostemma pentaphyllum (GP) on the bacteriophage lambda induced by ultraviolet (UV) irradiation have been studied. The results showed that GP could inhibit the UV induction of bacteriophage lambda in lysogenic cells. The inhibitory effects were dependent on the concentration and the reaction time of GP, and were efficient at 40 to approximately 125 microg ml(-1) for 10 min. The inhibitory rate was higher than 70% when the GP concentration was 50 microg ml(-1). By electron spin resonance (ESR) and spin-trapping techniques, the signals of free radicals were detected in the suspension of the lambda lysogenic bacteria induced by ultraviolet irradiation, but after the addition of GP the signals were decreased. These results indicate that gynostemma pentaphyllum not only is a scavenger of free radicals, but also possesses the biological function of anti-irradiation, and that there is a close relation between the UV irradiation of the bacteriaphage lambda and free radicals.

Immunogene therapy of tumors with vaccine based on Xenopus homologous vascular endothelial growth factor as a model antigen

Overcoming immune tolerance of the growth factors associated with tumor growth should be a useful approach to cancer therapy by active immunity. We used vascular endothelial growth factor (VEGF) as a model antigen to explore the feasibility of the immunogene tumor therapy with a vaccine based on a single xenogeneic homologous gene, targeting the growth factors associated with angiogenesis. To test this concept, we constructed a plasmid DNA encoding Xenopus homologous VEGF (XVEGF-p) and control vectors. We found that immunogene tumor therapy with a vaccine based on XVEGF was effective at both protective and therapeutic antitumor immunity in several tumor models in mice. VEGF-specific autoantibodies in sera of mice immunized with XVEGF-p could be found in Western blotting analysis and ELISA assay. The purified immunoglobulins were effective at the inhibition of VEGF-mediated endothelial cell proliferation in vitro, and at antitumor activity and the inhibition of angiogenesis by adoptive transfer in vivo. The elevation of VEGF in the sera of the tumor-bearing mice could be abrogated with XVEGF-p immunization. The antitumor activity and production of VEGF-specific autoantibodies, significantly elevated IgG1 and IgG2b, could be abrogated by the depletion of CD4(+) T lymphocytes. The observations may provide a vaccine strategy for cancer therapy through the induction of autoimmunity against the growth factors associated with tumor growth in a cross reaction with single xenogeneic homologous gene and may be of importance in the further exploration of the applications of other xenogeneic homologous genes identified in human and other animal genome sequence projects in cancer therapy.

Molecular cloning and characterization of four scorpion K(+)-toxin-like peptides: a new subfamily of venom peptides (alpha-KTx14) and genomic analysis of a member

Four full-length cDNAs encoding the precursors of four K(+)-toxin-like peptides (named BmKK(1), BmKK(2), BmKK(3) and BmmKK(4), respectively) were first isolated from a venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch. The deduced precursors of BmKK(1), BmKK(2) and BmKK(3) are all made of 54 amino acid residues including a signal peptide of 23 residues, and a mature toxin of 31 residues with three disulfide bridges. The precursor of BmKK(4) is composed of 55 amino acid residues including a signal peptide of 23 residues, a mature toxin of 30 residues cross-linked by three disulfide bridges, and an extra Gly-Lys tail which should be removed in the processing step. The four peptides displayed 24-97% sequence identity with each other, and less than 27% homology with any other scorpion toxins described. However, they shared a common disulfide bridge pattern, which was consistent with that of most short-chain K(+)-toxins, suggesting they represent a new class of scorpion toxins and their target receptors may be a subfamily of K(+) channels. We classified the BmKK toxin subfamily as alpha-KTx14 according to the classification rules. The genomic sequence of BmKK(2) was also cloned and sequenced. It consisted of two exons, disrupted by an intron of 79 bp inserted in the region encoding the C-terminal part of the signal peptide. This structure was very similar to that of other K(+)-toxins described previously.

[Anatomical study and clinical application of long head of triceps muscle for reconstruction of shoulder abduction]

OBJECTIVE

To study the morphological character of long head of triceps muscle for clinical application in reconstruction of shoulder abduction.

METHODS

Forty-four upper extremities of fixed human adult cadavers were carefully dissected. The origins and the pedicles of blood vessels and nerves of long head of triceps muscle, as well as the maximum available size of the muscles, were measured. Six cases of clinical application of long head of triceps muscle for reconstruction of shoulder abduction were followed up for 3 to 11 months.

RESULTS

The origins in the dorsal side of long head of triceps muscle were muscular and the ventral side were tendinous, which was 7.6 to 13.3 cm in length and 1.6 to 3.4 cm in width. The distance from the origin to the neurovascular pedicle was 5.7 to 11.4 cm. The radial nerve, which innervated the muscles, could be dissected for 2.9 to 11.8 cm in length. The blood supplies to the triceps muscle were from humeral artery (43.2%), 1.0 to 6.0 cm in length and 1.6 to 2.4 mm in diameter, and from humeral profundus artery (45.5%), 1.5 to 4.4 cm in length and 0.9 to 2.4 mm in diameter, if the vessel was separated to the humeral artery, the length was 1.5 to 6.3 cm. The neurovascular pedicles were multiple branched. In the 6 cases of clinical application of the triceps muscles, the operated shoulder could abduct from 5 degrees preoperatively (0 degree to 10 degrees) to 77.3 degrees (50 degrees to 90 degrees) postoperatively.

CONCLUSION

In accordance to the anatomical character of the triceps muscles, the long head of triceps muscle is a suitable choice for reconstruction of shoulder abduction with optimistic outcomes.

[Dominant selecting culture medium of Peucedanum decursivum by orthogonal design]

OBJECTIVE

To select the optimum medium for callus culture of Peucedanum decursivum.

METHOD

Orthogonal design was applied in determination of hormonal kinds and concentration, and qualitative analysis of callus was done initially.

RESULTS

The MS basic medium with 1 mg/L 2,4-D was the best one; coumarin was detected in callus preliminarily.

CONCLUSION

It was effective that orthogonal design applied in screening medium; feasible foundation was offered for Peucedanum decursivum cell culture producing active ingredient.

Primary studies on heroin abuse and injury induced by oxidation and lipoperoxidation

OBJECTIVE

To further reveal serious risks of heroin abuse to human body and clarify grave injuries of oxidation, peroxidation and lipoperoxidation induced by nitric oxide and other free radicals to heroin abusers.

METHODS

Determined and compared plasma levels of nitric oxide (P-NO), vitamin C (P-VC), vitamin E (P-VE), beta-carotene (P-beta-CAR), lipoperoxides (P-LPO) and erythrocyte activities of superoxide dismutase (E-SOD), catalase (E-CAT), glutathione peroxidase (E-GSH-Px) and erythrocyte level of lipoperoxides (E-LPO) in 137 cases of heroin abusers (HAs) and 100 cases of healthy volunteers (HVs), used linear regression and correlation, stepwise regression and correlation to analyze correlation among heroin-abusing-duration (HAD), daily-heroin-abusing-quantity (DHAQ) with above determination values in the HAs.

RESULTS

Compared with the above average values in the HVs group, the average values of P-NO, P-LPO, E-LPO in the HAs group were significantly increased (P < 0.0001), the average values of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT and E-GSH-Px were significantly decreased (P < 0.0001); the analysis of linear regression and correlation showed that with ascending of the HAD and DHAQ in the HAs, the values of P-NO, P-LPO, E-LPO were gradually increased (P < 0.0001), the values of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT, E-GSH-Px were gradually decreased (P < 0.0001); the analysis of stepwise regression and correlation suggested that the correlation among the HAD, DHAQ with the values of P-NO, P-VC, P-VE was the closest.

CONCLUSION

The balance between oxidation and antioxidation in the HAs was seriously destroyed, and the injuries induced by nitric oxide and other free radicals, oxidation, peroxidation and lipoperoxidation reactions to the body of HAs gravely exacerbated. In the abstaining from heroin dependence, therefore, it should consider that sufficient quantum antioxidants such as VC, VE and beta-CAR are dosed to the HAs so as to abate the injuries to their bodies.

Molecular cloning and genomic organization of a K(+) channel toxin from the Chinese scorpion Buthus martensii Karsch

A full-length cDNA encoding the precursor of a K(+) channel toxin (BmTX2) was first isolated from a venom-gland cDNA library of the Chinese scorpion Buthus martensii Karsch. The precursor is composed of a signal peptide of 21 residues and a mature toxin of 37 residues with three disulfide bridges. The genomic gene of BmTX2 was also cloned and sequenced. It consisted of two exons, disrupted by an intron of 81 bp inserted in the region encoding signal peptide.

Effect of copper aspirinate on contraction of isolated rabbit aortic strips

AIM

To investigate the effect of copper aspirinate on contraction of vascular smooth muscle.

METHODS

Isolated rabbit aortic strips, including intact endothelium strips and endothelial cell-denuded aortic strips, were suspended in modified Krebs'solution to determine effects of copper aspirinate on the contraction induced by norepinephrine (NE), KCl, and CaCl2, while CuSO4, aspirin, and vehicle were used as controls.

RESULTS

Copper aspirinate possessed antagonistic effect on contraction of rabbit aortic strips induced by NE with an IC50 value of 31 nmol/L, while CuSO4 had much l ess antagonistic effect with an IC50 value of 0.29 micromol/L, and aspirin did not work in the same preparation. No effect of copper aspirinate were found on the contraction induced by KCl and CaCl2. Effects on endothelial cell denuded aortic strips were similar to those in the normal aortic strips.

CONCLUSION

Copper aspirinate possessed different effects from aspirin and CuSO4 on vascular smooth muscles. It inhibited contraction induced by NE with an activity stronger than CuSO4 at the same Cu2+ concentration, this action might be due to blockade of the receptor-operated Ca2+ channels, and it might not be linked to the endothelium.

Molecular cloning and sequence analysis of cDNAs encoding a beta-toxin-like peptide and two MkTx I homologues from scorpion Buthus martensii Karsch

Three full-length cDNAs, one encoding the precursor of a beta-toxin-like peptide (named BmKBT) and the other two encoding those of (MkTx I) homologues (named MkTx II and MkTx III, respectively), were isolated from a venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch, by screening with a cDNA fragment generated by PCR. The encoded precursor of BmKBT contained 83 amino acid residues including a signal peptide of 19 residues, a mature peptide of 63 residues and an extra basic residue (Lys) which have to be removed in the processing step. The deduced amino acid sequence of BmKBT showed 52% homology to that of beta-neurotoxin TsVII isolated from scorpion Tityus serrulatus. However, the positions of disulfide bridges have a little variation between the two peptides. The precursors of MkTx II and MkTx III both contained 85 amino acid residues including a signal peptide of 19 residues, a mature peptide of 64 residues and two extra residues (Gly-Arg) which have to be removed in the processing step, too. There was high sequence similarity (90%) between the two peptides. The sequences of mature MkTx II and MkTx III were highly homologous with MkTx I isolated from scorpion Buthus martensii Karsch, both showing 90% identities.

Blockade of GRP receptors inhibits gastric emptying and gallbladder contraction but accelerates small intestinal transit

BACKGROUND & AIMS

This study was designed to characterize [D-F(5)Phe(6)D-Ala(11)]Bn(6-13)OMe (BIM26226) as a gastrin-releasing peptide (GRP)-preferring bombesin receptor antagonist and to determine whether GRP physiologically regulates gastrointestinal motility. Intravenous BIM26226 (5-500 microg. kg(-1). h(-1)) inhibits GRP-induced gallbladder contraction and plasma cholecystokinin (CCK) release in a dose-dependent fashion.

METHODS

Gastric emptying and small bowel transit of a solid meal were quantified using scintigraphy. Meal-stimulated gallbladder contraction was measured by sonography in a 2-period crossover design.

RESULTS

Intravenous BIM26226 potently inhibited gastric lag time (114 +/- 7 vs. 41 +/- 6 minutes [control]) and gastric emptying rate (0.11 +/- 0.02%/min vs. 0.26 +/- 0.04%/min [control]), whereas concomitant infusion of BIM26226 accelerated small bowel transit time (153 +/- 41 vs. 262 +/- 20 minutes [control]). A continuous liquid meal perfusion into the duodenum induced complete gallbladder contraction (t(50%), 35 +/- 4 minutes), which BIM26226 inhibited significantly (t(50%), 64 +/- 8 minutes). BIM26226 did not alter plasma CCK response, indicating that circulating CCK did not mediate these effects.

CONCLUSIONS

These data show that BIM26226 is a potent antagonist of exogenous and endogenous GRP and suggest that GRP is a major physiologic regulator of gastric emptying, small bowel transit, and gallbladder contraction.

[A pharmacognostical study on Eomecon chionathe Hance]

The morphological and histological characters for the identification of Eomecon chionathe Hance was illustrated in this paper.

Immunotherapy of tumors with xenogeneic endothelial cells as a vaccine

The breaking of immune tolerance against autologous angiogenic endothelial cells should be a useful approach for cancer therapy. Here we show that immunotherapy of tumors using fixed xenogeneic whole endothelial cells as a vaccine was effective in affording protection from tumor growth, inducing regression of established tumors and prolonging survival of tumor-bearing mice. Furthermore, autoreactive immunity targeting to microvessels in solid tumors was induced and was probably responsible for the anti-tumor activity. These observations may provide a new vaccine strategy for cancer therapy through the induction of an autoimmune response against the tumor endothelium in a cross-reaction.

Cloning and characterization of a cDNA sequence encoding the precursor of a chlorotoxin-like peptide from the Chinese scorpion Buthus martensii Karsch

A full-length cDNA sequence encoding the precursor of a venom peptide with homology to chlorotoxin (named BmKCT) was isolated from a cDNA library made from the venom glands of the Chinese Scorpion Buthus martensii Karsch. The encoded precursor of BmKCT was 59 amino acid residues long including a signal peptide of 24 residues and a mature toxin of 35 residues with four disulfide bridges. The sequence of BmKCT is similar (68% identities) to that of chlorotoxin isolated from Leiurus quinguestriatus quinquestriatus. BmKCT is the first report of the cDNA sequences encoding four-disulfide-bridged short-chain toxins from Buthus martensuii Karsch so far.

Cloning and characterization of the cDNA sequences of two venom peptides from Chinese scorpion Buthus martensii Karsch (BmK)

From a cDNA library made from venom glands of Chinese scorpions of Buthus martensii Karsch, full-length cDNAs encoding precursors of two venom peptides have been isolated using a cDNA probe synthesized by polymerase chain reaction. Sequence analysis of the cDNAs revealed that one encoded precursor was 85 amino acid residues long including a signal peptide of 19 residues and a mature peptide (named BmK T) of 66 residues, and another encoded precursor was 84 residues long containing the same length signal peptide and a mature peptide (BmK M4 isoform, named BmK M4') of 64 residues. The analysis of amino acid sequence similarity indicated that the BmK T was homologous with both mammalian and insect toxins from BmK scorpion or other scorpions, and the BmK M4' was highly homologous with the members of the mammalian neurotoxin family of BmK, having two point mutations in amino acid residue sequence compared to BmK M4, a natural toxin from BmK.

[Quantification analysis of vascular endothelial cells in human solid tumor]

Angiogenesis is essential for the growth and metastasis of solid tumors. Intratumoral microvessel count, which represents a measure of tumor angiogenesis, has been associated with prognosis of patients with a variety of malignancies. But till now, it is still a problem to quantitate the angiogenesis of tumors exactly. In this study, the endothelial cells in 20 solid tumors were conjugated with anti-CD34 monoclonal antibodies labelled with red-fluorescent substances, and were observed by fluorescence microscopy and quantitated by flow cytometry. The results of flow cytometry were analysed by t-test. The correlation was analysed between percentage of flow cytometry and vessel counts (light microscopy, x 200) in each tumor which was stained with anti-CD34 monoclonal antibodies and anti-VIII factor related antigen polyclonal antibodies by using immunohistochemistry. The results showed there was significant difference between the treatment group and control group in flow cytometry, and a significant correlation between the endothelial cells percentage by flow cytometry and the vessel counts by immunohistochemistry was observed, although the average vessel counts were approximately three times with CD34 staining as much as with VIII factor related antigen staining. These data indicate that flow cytometry as a novel method can quantitate angiogenesis of tumors exactly and quickly.

[The relationship of cellular DNA content with clinical stage and biological features of colorectal cancer]

The purpose of this study was to explore the relationship of cellular DNA content with clinical stage and biological features of cancer. Flow cytometry was performed on fresh specimens from 86 patients from 1997 to 1998. Forty-five (53.3%) specimens were found to contain cells with abnormal DNA (DNA nondiploidy). Although none of the sex, age, site, differentiation variables correlated with flow cytometric DNA ploidy, nondiploidy was associated with Dukes' stage and lymph node metastasis. Duke's A stage tumors were more frequently diploid than were more advanced tumors, but no difference between Duke's B, C and D stages were observed. These findings suggest that ploidy is associated with some pathological factors.

Antagonism of NPY-induced feeding by pretreatment with cyclic AMP response element binding protein antisense oligonucleotide

Although second messenger systems subserving neuropeptide Y (NPY)-mediated behaviors have been identified for a variety of receptors in several tissues, downstream signaling events are not well known. The nuclear binding protein, cyclic AMP response element binding protein (CREB) appears to be a transcription factor that is activated following injection of NPY into rat hypothalamus. To allow determination of the functional nature of CREB mediation of NPY-induced feeding, injection cannulae were implanted into the perifornical hypothalamus of 18 rats. Treatment of seven rats with CREB antisense oligonucleotide (15 ug) significantly antagonized NPY feeding for up to one week after treatment, while similar injections of CREB sense oligonucleotide (15 ug) had no significant effect on NPY-induced feeding. Two weeks after the antisense oligonucleotide treatment, feeding was once again elicited by the injection of NPY. Hypothalamic CREB protein was also reduced significantly two days after the CREB antisense oligonucleotide treatment. These results suggest that activation of CREB, probably through phosphorylation, may be a necessary event for the signal transduction of NPY stimulation into feeding behavior.

The abnormality of glucose transporter in the erythrocyte membrane of Chinese type 2 diabetic patients

Type 2 diabetes mellitus is characterized by impaired glucose uptake. With a photometric method of recording the erythrocyte suspension absorption during the course of glucose transport across the membranes, we observed that the initial rate of glucose zero-trans entry was decreased significantly in 30 Chinese type 2 diabetic patients as compared to 25 healthy controls. The rate of glucose infinite-cis efflux exhibited no difference between the patients and controls. The measurement of temperature dependence of glucose transport showed that the activation energy for glucose entry was increased in diabetic patients. The inhibitory constant of glucose entry by cytochalasin B (CB) in patients was similar to that of the controls. However, we found that the inhibitory constant was increased significantly in the patient erythrocytes after phloretin treatment. After the erythrocytes were made into stripped white ghosts, the fluorescence quenching experiment was performed. Glucose, CB and phloretin can quench the fluorescence of tryptophan residues in the glucose transporter 1, GLUT1. The abnormality of fluorescence quenching in the erythrocyte membranes of patients was observed. The transfer tendency of tryptophan residues from the hydrophilic environment to the hydrophobic environment was decreased in patient ghosts as binding with glucose, and the opposite tendency appeared as CB and phloretin instead of glucose. We conclude that the decreased in glucose entry in the erythrocyte membranes of diabetic patients was due to the GLUT1 change in structure - mostly the outer domain of the glucose transporter.

Cloning and characterization of a novel cDNA sequence encoding the precursor of a novel venom peptide (BmKbpp) related to a bradykinin-potentiating peptide from Chinese scorpion Buthus martensii Karsch

Based on the amino acid sequence of a bradykinin-potentiating peptide (Bpp) (peptide K-12) from scorpion Buthus occitanus, a full-length cDNA sequence encoding the precursor of a novel venom peptide (named BmKbpp) related to this Bpp, has been isolated and analyzed. The cDNA encodes a precursor of 72 amino acid residues, including a signal peptide of 22 residues and an extra Arg-Arg-Arg tail at the C-terminal end of the precursor, which have to be removed in the processing step. The C-terminal region (21 residues) of the precursor is homologous (57% identical) with the sequence of peptide K-12. Thus, according to the primary structure of the BmKbpp precursor, there may be a propeptide between the signal peptide and the putative mature BmKbpp at the C-terminal region of the precursor.

[Observation on morphology and histology of Angelica dahurica (Fisch. ex Hoffm.) Benth. et Hook. f. var. formosana (Boiss.) Shan et Yuan in the process of in vitro cultivation and polyploid induction]

OBJECTIVE

To explore the relationship between morphogenesis and histogenesis in the process of in vitro cultivation of Angelica dahurica f. var. formosana, and determine the best period for its polyploid induction.

METHOD

In the different periods of in vitro cultivation, the explants were obtained and their sections observed. When the adventitiousbuds began to differentiate, aqueous solution was applied for polyploid induction.

RESULT

The adventitious buds were mainly externally originated and thus fit for polyploid induction. The most appropriate period for induction was around the 38th day of cultivation.

CONCLUSION

Induction treatment can be used as an effective biotechnological approach to adventitious buds in the process of tissue cultivation.

[Experiment on polyploid induction of Angelica dahurica var. formosana]

Colchicine solution was applied to the primary adventitious buds of Angelica dahurica var. formosana in vitro to induce the polyploid. Compared with non-treated plantlet, the morphology, microhisology, and chromosome number of treated plantlets are varied. It proved that the polyploid induction was effective.

[Hemorrheological status in patients with silicosis and its clinical significance]

OBJECTIVE

To study relationship between silicosis and hemorrheology and its clinical significance.

METHODS

Varied indices for hemorrheology were measured in 85 male patients with silicosis, 45 male patients with chronic bronchitis and 100 healthy male subjects.

RESULTS

Compared with the control group and the chronic bronchitis patient group, average hematocrit (Hct), whole blood apparent viscosity (eta(a)) at 4 s(-1) - 200 s(-1) shear rates, plasma viscosity (eta(p)), erythrocyte electrophoresis time (EET) and platelet electrophoresis time (PET) all significantly increased in patients with silicosis (P < 0.001). Hemorrheological indices in patients with silicosis increased with severity of disease, increased with decrease in their pulmonary function, and were all significantly higher than those in the control group (P < 0.01 approximately equal 0.001). Stepwise regression analysis showed that severity of disease correlated closely to Hct, eta(a) at 4 s(-1) - 200 s(-1), EET and PET, and that pulmonary function status in patients with silicosis and their courses correlated closely to Hct, eta(a) at 4 s(-1) - 200 s(-1), eta(p), EET and PET.

CONCLUSIONS

Blood of patients with silicosis was in highly viscose status, which was easy to be complicated with multiple diseases.

Massive and widely distributed splenosis

A 45-year-old man, seropositive for hepatitis C, was examined because his liver was palpable well below the costal margin. A CT examination revealed multiple nodules within the liver and also several sites of ectopic tissue. The patient had a splenectomy 25 years before. A radiocolloid study showed uptake, consistent with splenosis, in the thorax, abdomen, pelvis, and possibly the left arm. The magnitude of the ectopic tissue, and its multiple locations, indicated the ability of splenic cells to grow in a variety of body sites.

Longitudinal changes in optic disc topography of adult patients after trabeculectomy

OBJECTIVE

To study longitudinal changes in optic disc topography after trabeculectomy in adult patients.

DESIGN

Prospective case series.

PARTICIPANTS

Twenty-five eyes of 25 patients undergoing trabeculectomy were enrolled.

INTERVENTION

Images of the optic disc were obtained preoperatively and approximately 2 weeks, 4 months, and 8 months after surgery by use of a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph).

MAIN OUTCOME MEASURES

The topographic optic disc parameters (cup volume, cup area, rim volume, rim area, cup-disc area ratio, mean cup depth, maximum depth, cup shape, and height variation contour) were measured automatically for each image with the Heidelberg Retina Tomograph Software (version 1.11).

RESULTS

Approximately 2 weeks after surgery, the mean preoperative intraocular pressure (IOP) of 19.3 mmHg (SD, 6.4 mmHg) decreased to 6.0 mmHg (SD, 3.6 mmHg), cup volume and mean cup depth decreased, height variation contour increased, and the cup shape parameter became more negative. Approximately 4 months after surgery, mean IOP was 9.7 mmHg (SD, 4.2 mmHg), and the only statistically significant change from preoperative values of optic disc parameters was in the cup shape measure. Approximately 8 months after surgery, there was no statistically significant change in any of the optic disc parameters compared with preoperative values, although IOP was 10.4 mmHg (SD, 5.9 mmHg).

CONCLUSIONS

Changes in the optic disc that may be present 2 weeks after a trabeculectomy do not appear to persist 4 and 8 months later in eyes with advanced glaucomatous optic nerve damage, except for cup shape, which was different from preoperative values at 4 months but not at 8 months.

[Study on the correlation of silicosis with antioxidant and antioxidase]

Plasma vitamin C(P-VC), vitamin E(P-VE) and beta-carotene(P-beta-CAR) contents and the activities of superoxide dismutase(E-SOD), catalase(E-CAT) and glutathione peroxidase (E-GSH-Px) in erythrocyte in 73 silicosis patients and 60 healthy control subjects were measured. The average levels of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT and E-GSH-Px of patients were significantly lower than those of the controls (P < 0.001). All indexes were correlated to the course, condition and pulmonary function of silicosis patients. The results analyzed by stepwise regression showed that the correlation between course, condition and pulmonary function of patients and P-VE and E-SOD was close. The balance between oxidation and the antioxidation in silicosis patients may be disturbed, and oxygen free radical reaction may be pathologically exacerbated.

Reciprocal changes in hypothalamic receptor binding and circulating leptin in anorectic tumor-bearing rats

Although reduced biological activity of the obese gene product, leptin, has been associated with obesity, little information is available concerning leptin alterations during anorexia. Therefore, we measured circulating leptin concentrations and hypothalamic leptin binding in anorectic tumor-bearing and pair-fed control rats. Plasma concentrations of leptin decreased in tumor-bearing rats early in the course of tumor growth, and fell to nearly non-detectable levels during severe anorexia. The pair-fed control rats that ate the same amount of food as did the anorectic tumor-bearing rats exhibited a 50% decrease in plasma leptin concentration. Concentrations of free fatty acids were elevated in both tumor-bearing and pair-fed groups, while circulating levels of triglycerides were increased only in anorectic tumor-bearing rats. Leptin receptor density was doubled in the hypothalamus of tumor bearing rats, while binding affinity was decreased by 50%. These results suggest that peripheral leptin production is down-regulated, perhaps due to increased lipolysis in tumor-bearing rats. It appears that hypothalamic leptin systems up-regulate receptor numbers in response to decreased blood leptin level, however, the decrease in binding affinity may compensate for these alterations. Therefore, the influence of leptin on hypothalamic neuropeptide Y feeding systems may be minimal in anorectic tumor-bearing rats.

Activation of the cyclic AMP pathway by alpha-melanotropin mediates the response of human melanocytes to ultraviolet B radiation

A hallmark of sun exposure is increased melanin synthesis by cutaneous melanocytes which protects against photodamage and photocarcinogenesis. Irradiation of human keratinocytes or melanocytes with ultraviolet (UV) rays stimulates the synthesis and release of alpha-melanotropin (alpha-MSH) and adrenocorticotropic hormone (ACTH), which induce cyclic AMP (cAMP) formation and increase the proliferation and melanogenesis of human melanocytes. We report that stimulation of cAMP formation is obligatory for the melanogenic response of cultured normal human melanocytes to UVB radiation. In the absence of cAMP inducers, UVB radiation inhibited, rather than stimulated, melanogenesis. UVB radiation (28 mJ/cm2) arrested melanocytes in the G1 phase of the cell cycle, and concomitant treatment with 0.1 microM alpha-MSH enhanced their proliferation but did not increase the surviving fraction. Irradiation with UVB, with or without alpha-MSH, caused prolonged expression of p53 and p21(waf-1, cip-1), maintained pRB in a hypophosphorylated state, and reduced the expression of Bcl2. However, alpha-MSH allowed UVB-irradiated melanocytes to enter S phase, suggesting that alpha-MSH acts as a mitogen rather than a survival factor, and that overexpression of p53 is mainly a signal for cell death. Our results underscore the importance of the cAMP pathway and its physiological inducers in mediating the response of human melanocytes to UV radiation.

Effect of quercetin on the in vitro and in vivo growth of mouse hepatoma cells

Quercetin has been reported to have tumor growth inhibition effect. We have examined the in vitro and in vivo effects of quercetin on the growth of ML-3 murine hepatoma cells. Our results showed that quercetin dose dependently inhibited the growth of ML-3 cells. Flow cytometric analysis showed that quercetin-treated cells were mainly arrested at G(0)-G(1) phases of the cell cycle. For the in vivo experiment, BALB/c mice were transplanted intrasplenicly with ML-3 hepatoma cells and fed with 2% quercetin in the diet. The survival of tumor-bearing mice and the size of hepatic tumor were recorded at 40 days after implantation of ML-3 cells. Significant increase in survival of tumor-bearing mice was found by quercetin treatment, all mice in the quercetin group survived to the end of the experiment while only 50% of the mice in control group survived. These results suggested that quercetin has potential for hepatoma treatment.