Determination of the iron state in ferrous iron containing vitamins and dietary supplements: application of Mössbauer spectroscopy

Determination of the iron state in commercially manufactured iron containing vitamins and dietary supplements is important for evaluation of pharmaceuticals quality. Mössbauer (nuclear gamma-resonance) spectroscopy was used for analyzing the iron state in commercial pharmaceutical products containing ferrous fumarate (FeC₄H₂O₄), ferrous sulfate (FeSO₄), ferrous bisglycinate chelate (Ferrochel^®) and ferrous iron (hydrolyzed protein chelate). Mössbauer parameters and the iron states were determined for iron compounds in the studied pharmaceuticals. Various ferric and ferrous impurities were found in all of the commercial products. The quantities of ferric impurities exceeded the FDA limitation of 2% in products containing ferrous fumarate. The quantities of ferric impurities exceeded 58% and 30% in products containing ferrous bisglycinate chelate and ferrous iron (hydrolyzed protein chelate), respectively. The presence of ferrous and ferric impurities was not related to the ageing of the vitamins and dietary supplements. Two pharmaceutical products contained major iron compounds, the Mössbauer parameters of which did not correspond to the ferrous fumarate or ferrous bisglycinate chelate claimed by the manufacturer.     

Iron sucrose – characteristics,efficacy and regulatory aspects of an established treatment of iron deficiency and iron-deficiency anemia in a broad range of therapeutic areas

Introduction: Iron is a key element in the transport and utilization of oxygen and a variety of metabolic pathways. Iron deficiency is a major cause of anemia and can be associated with fatigue, impaired physical function and reduced quality of life. Administration of oral or intravenous (i.v.) iron is the recommended treatment for iron-deficiency anemia (IDA) in different therapeutic areas.

Areas covered: This article provides an overview of studies that evaluated i.v. iron sucrose for anemia and iron status management, either alone or in combination with erythropoiesis-stimulating agents, across various diseases and conditions.

Expert opinion: Iron sucrose is an established, effective and well-tolerated treatment of IDA in patients with acute or chronic conditions such as chronic kidney disease, inflammatory bowel disease, pregnancy (second and third trimester), postpartum period, heavy menstrual bleeding and cancer who need rapid iron supply and in whom oral iron preparations are ineffective or not tolerated. Available data on patient blood management warrant further studies on preoperative iron treatment. First experience with iron sucrose follow-on products raises questions about their therapeutic equivalence without comparative clinical data in newly diagnosed patients or patients on existing chronic treatment.     

Dietary iron intakes and biochemical iron status of 15-49 year old women in New Zealand: is there a cause for concern?

AIM: To assess dietary iron intakes and biochemical iron status of a nationally representative sample of nonpregnant 15-49 year old women (n=1,751) in New Zealand. METHODS: A cross-sectional national survey was conducted in 1996/97. Women were selected via a multistage stratified cluster sampling procedure with increased sampling of Maori and Pacific women. Dietary iron intakes were estimated using a 24-hour diet recall. Biochemical iron status was assessed on a non-fasting venipuncture blood sample (n=1,047) via haemoglobin, mean cell volume, erythrocyte zinc protoporphyrin, transferrin receptors and serum ferritin. RESULTS: Average daily dietary iron intakes ranged from 9.6 mg/day among Pacific women to 10.5 mg/day among Maori women; 41% of 20-49 year olds and 45% of adolescents were at risk of low dietary iron intakes. The estimated percentage of 15-49 year old women with iron deficiency anaemia ranged from 1.4-5.5%, and for iron deficiency without anaemia from 0.7-12.6% depending on the age group and criteria used. CONCLUSIONS: The overall estimated prevalence of suboptimal biochemical iron status among 15-49 year old women in New Zealand ranged from 7-13%, which compared favourably with premenopausal women living in other western countries. This situation is, however, a public health concern given the potential negative functional consequences associated with even mild iron deficiency.     

Physicochemical and structural characterization of iron–sucrose formulations: a comparative study

Abstract

Intravenous polynuclear iron formulations are vital components in the treatment of iron deficiency anemia associated with chronic kidney disease as well as other diseases associated with gastro-intestinal and cardio-vascular system. Intravenous iron preparations consist of iron–carbohydrate nanoparticles with iron–oxyhydroxide as a core covered by carbohydrate shell. These preparations should be very well characterized in terms of their physicochemical properties and pharmacological profile in order to establish safety and efficacy. The present research work was aimed to physicochemically characterize a new generic iron–sucrose preparation (IS-Claris) and establish its equivalency with the reference product (Venofer®). Various analytical techniques including gel permeation chromatography (GPC), mass spectroscopy (MALDI-TOF), absorption spectroscopy, X-ray diffraction analysis (XRD), nuclear magnetic resonance spectroscopy (proton and ¹³C NMR), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) were employed. It was observed that the specifications of IS-Claris obtained through these analyses reflect those of Venofer® and hence the two formulations were considered comparable.     

NADPH and iron may have an important role in attenuated mucosal defense in Helicobacter pylori infection?

Host intracellular iron has been recognized as an important cofactor in induction of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent oxidative burst as antimicrobial defense mechanism. It is plausible that iron chelator directly inactivates NADPH oxidase by chelating the active site heme iron of flavocytochrome b558 thus blocking the transfer of electrons from NADPH to oxygen and its reduction to superoxide anion. Thus, altering the equilibrium of intracellular iron could influence the course of infection to the enhancement of the pathogen with regard to oxidative stress.     

Cytotoxicity and genotoxicity of size-fractionated iron oxide (magnetite) in A549 human lung epithelial cells: role of ROS, JNK, and NF-κB

Airborne particulate matter (PM) of varying size and composition is known to cause health problems in humans. The iron oxide Fe(3)O(4) (magnetite) may be a major anthropogenic component in ambient PM and is derived mainly from industrial sources. In the present study, we have investigated the effects of four different size fractions of magnetite on signaling pathways, free radical generation, cytotoxicity, and genotoxicity in human alveolar epithelial-like type-II cells (A549). The magnetite particles used in the exposure experiments were characterized by mineralogical and chemical techniques. Four size fractions were investigated: bulk magnetite (0.2-10 μm), respirable fraction (2-3 μm), alveolar fraction (0.5-1.0 μm), and nanoparticles (20-60 nm). After 24 h of exposure, the A549 cells were investigated by transmission electron microscopy (TEM) to study particle uptake. TEM images showed an incorporation of magnetite particles in A549 cells by endocytosis. Particles were found as agglomerates in cytoplasm-bound vesicles, and few particles were detected in the cytoplasm but none in the nucleus. Increased production of reactive oxygen species (ROS), as determined by the 2',7'-dichlorfluorescein-diacetate assay (DCFH-DA), as well as genotoxic effects, as measured by the cytokinesis block-micronucleus test and the Comet assay, were observed for all of the studied fractions after 24 h of exposure. Moreover, activation of c-Jun N-terminal kinases (JNK) without increased nuclear factor kappa-B (NF-κB)-binding activity but delayed IκB-degradation was observed. Interestingly, pretreatment of cells with magnetite and subsequent stimulation with the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) led to a reduction of NF-κB DNA binding compared to that in stimulation with TNFα alone. Altogether, these experiments suggest that ROS formation may play an important role in the genotoxicity of magnetite in A549 cells but that activation of JNK seems to be ROS-independent.     

Comparison of the intestinal absorption and bioavailability of γ-tocotrienol and α-tocopherol: in vitro, in situ and in vivo studies

The aim of this work was to compare the intestinal absorption kinetics and the bioavailability of γ-tocotrienol (γ-T3) and α-tocopherol (α-Tph) administered separately as oil solutions to rats in vivo. Also, to explain the significant difference in the oral bioavailability of the compounds: (1) the release profiles using the dynamic in vitro lipolysis model, (2) the intestinal permeability and (3) carrier-mediated uptake by Niemann-Pick C1-like 1 (NPC1L1) transporter were examined. Absolute bioavailability studies were conducted after oral administration of γ-T3 or α-Tph prepared in corn oil to rats. In situ rat intestinal perfusion with ezetimibe (a NPC1L1 inhibitor) was performed to compare intestinal permeability. The in vitro interaction kinetics with NPC1L1 was examined in NPC1L1 transfected cells. While the in vitro release studies demonstrated a significantly higher release rate of γ-T3 in the aqueous phase, the oral bioavailability of α-Tph (36%) was significantly higher than γ-T3 (9%). Consequent in situ studies revealed significantly higher intestinal permeability for α-Tph compared with γ-T3 in rats. Moreover, the NPC1L1 kinetic studies demonstrated higher Vmax and Km values for α-Tph compared with γ-T3. Collectively, these results indicate that intestinal permeability is the main contributing factor for the higher bioavailability of α-Tph. Also, these results emphasize the potentially important role of intestinal permeability in the bioavailability of γ-T3, suggesting that enhancing its permeability would increase its oral bioavailability.     

Comparison of the in vitro binding characteristics of the β-carbolines harman and norharman in rat brain and liver and in bovine adrenal medulla

The in vitro binding of the naturally occurring -carbolines harman and norharman in their tritium-labelled forms to cell membranes from the rat brain and liver and from bovine adrenal medulla was investigated. Displacement of the specific [³H]harman binding in bovine adrenal medulla and rat liver by several -carbolines and monoamine oxidase (MAO) inhibitors revealed the pharmacological profile of a single, high-affinity binding site (K _D 4.92±0.43 nmol/l, B_max 8.47±0.17 pmol/mg protein; adrenal medulla) which corresponded to the active site of MAO type A (MAO-A). Similar characteristics have previously been found for brain tissue from rat, marmoset and pig. In order to determine the temperature dependence of the [³H]harman binding, the K _D and B_max values for rat cerebral cortex were calculated from the results of saturation experiments at 5 temperatures (range: 0°C–37°C). Whereas the B_max values under all conditions were – 4 pmol/mg protein, the K _D values, with increasing temperature, ranged from 3 nmol/l to 30 nmol/l. The calculated linear van't Hoff plot (-In K _D against 1/T) suggested an enthalpy-driven binding of [³H]harman to MAO-A.At least three different [³H]norharman-binding sites were detected. In the rat forebrain, 85% of the specific binding (at about 2 nmol/l of [³H]norharman) can be attributed to a MAO binding site of type B: the binding is displaceable, in nmol/l concentrations by the potent and selective MAO-B inhibitors MDL 72,974A, R(–)-deprenyl and pargyline and, in mol/l concentrations, by S(+)-deprenyl and the potent and selective MAO-A inhibitors clorgyline, harmine, harman, harmaline, brofaromine 5-F--methyltryptamine. After suppression of the MAO binding sites with 1 mol/l clorgyline and mol/l R(–)-deprenyl, a second binding site was found. However, the binding at this site was biphasically displaceable by harman and norharman (Hill-slopes about 0.5 and 0.6, curvilinear Rosenthal plots) suggesting the presence of negative co-operativity or of two binding sites (states). A similar clorgyline/R(–)-deprenyl resistent single (Hill-slopes of displacement by norharman, harman and 6-hydroxy--carboline about unity; linear Rosenthal plots) high affinity binding site (K _D 7.5±2 nmol/l, B_max 130±30 fmol/mg protein) was found in bovine adrenal medullary cell membranes. A third quite different clorgyline/R(–)-deprenyl resistent high-affinity (K _D14 nmol/l) and high-density (B_max 10–30 pmol/mg protein) binding site was detected in the liver. The specific binding at this site was not displaceable by harman or most other substituted -carbolines or by tetrahydro--carbolines, but was displaced by norharman and several newly synthesized 6-substituted aromatic -carbolines (e.g. F-, CH₃-, CH₃O-, HO-). The [³H]norharman binding site in the liver is certainly not identical with any of the binding sites for MAO-inhibitors, benzodiazepines or sigma receptor ligands and is slightly enriched in the microsomal (P₃) fraction whereas most of the specific [³H]harman binding was detected in the crude mitochondrial (P₂) fraction. Correspondence to: T. May at the above address     

Bioavailability and disposition of ‘H-solanine in rat and hamster

1. The toxicokinetics of [³H]-α-solanine after oral (p.o.) and intravenous (i.v.) administration in rat and hamster were studied, in order to decide which is the most appropriate model in risk assessment studies. The i.v. Dose was 54 βg/kg; the oral dose was 170 βg/kg.

2. After i.v. Administration, the toxicokinetics of total radioactivity in blood were comparable in rat and hamster. However, the clearance of total radioactivity from plasma was more effective in rat than in hamster. The half-lives of distribution and of the terminal phase of unchanged α-solanine were not different between rat and hamster, whereas the systemic and metabolic clearance were, respectively, about 1.6 and 2.7 times higher in rat than in hamster. The clearance of unchanged α-solanine is more effective than of total radioactivity.

3. After p.o. Administration in rat and hamster, the mean bioavailability of total radioactivity is about 29 and 57%, respectively. The bioavailability of unchanged α-solanine is only 1.6 and 3.2%, respectively, when compared with i.v. administration.

4. T_1/2el of α-solanine after p.o. Administration was in rats a factor of four and in hamsters a factor of two shorter than after i.v. Administration. A strong retention of radioactivity was seen in the hamsters after p.o. Administration; only 40% of the dose was excreted within 7 days versus 90% in rat.

5. Based on these and toxicological data from literature, it was decided that the hamster is a more appropriate model in (sub) chronic toxicity studies with α-solanine than the rat.     

Detection and quantitation of β-blockers in plasma and urine

β-blockers are a class of antihypertensive drugs that are used for the management of cardiac arrhythmias, cardioprotection after myocardial infarction (heart attack) and hypertension. They have revolutionized the medical management of angina pectoris and are recommended as first-line agents by national and international guidelines. Although β-blockers are still the cornerstone for the treatment of heart failure, some of the drugs in this category are prohibited in several sports requiring vehicle control and bodily movements as they reduce heart rate and tremors, and improve performance. As a result, urine analysis of β-blockers is mandatory in doping control and toxicological screening. The determination of plasma levels of β-blockers helps to ensure noncompliance in patients with persistent hypertonia to confirm the diagnosis of β-blocker poisoning and for therapeutic drug monitoring. This review provides a comprehensive account of various analytical methods developed for detection and quantitation of β-blockers in plasma and urine.     

Effect of lactoferrin- and transferrin-conjugated polymersomes in brain targeting： in vitro and in vivo evaluations

Aim:

To evaluate the effect of lactoferrin (Lf) and transferrin (Tf) in brain targeting.

Methods:

Polymersomes (PSs), employed as vectors, were conjugated with Lf or Tf and were characterized by morphology, particle size, zeta potential, and surface densities of the Lf or Tf molecules. In vitro uptake of Lf-PS and Tf-PS by bEnd.3 cells was investigated using coumarin-6 as a fluorescent probe. In vivo tissue distribution and pharmacokinetics of ¹²⁵I-Lf-PS and ¹²⁵I-Tf-PS were also examined.

Results:

The mean particle size of PS, Lf-PS, and Tf-PS was around 150 nm and the zeta potential of the PSs was about -20 mV. Less than 0.12% of the coumarin was released from coumarin-6-loaded PS in 84 h indicating that coumarin-6 was an accurate probe for the PSs'' behavior in vitro. It was shown that the uptake of Lf-PS and Tf-PS by bEnd.3 cells was time-, temperature-, and concentration-dependent. Both Lf and Tf could increase the cell uptake of PSs at 37°C, but the uptake of Tf-PS was significantly greater than that of Lf-PS. In vivo tissue distribution and pharmacokinetics in mice revealed higher brain uptake and distribution of Tf-PS than Lf-PS, which was in accordance with in vitro uptake results. The drug targeting index (DTI) of Tf-PS with regard to Lf-PS was 1.51.

Conclusion:

Using a PS as the delivery vector and bEnd.3 cells as the model of the blood-brain barrier (BBB), Tf was more effective than Lf in brain targeting.     

Formulation and optimization of alkaline extracted ispaghula husk microparticles of isoniazid – in vitro and in vivo assessment

Microparticles containing isoniazid were prepared by the emulsification internal ionic gelation method using a novel, alkaline extracted ispaghula husk as a wall forming material. A four-factor three-level Box–Behnken design was employed to study the effect of independent variables on dependent variables. Sodium alginate concentration (X₁), alkaline extraction of ispaghula husk (AEISP) concentration (X₂), concentration of cross-linking agents (X₃) and stirring speed (X₄) were four independent variables considered in the preparation of microparticles, while the particle size (Y₁) and entrapment efficiency (Y₂) were dependent variables. Optimized microparticles exhibited 83.43% drug entrapment and 51.53?µm particle size with 97.80% and 96.37% validity, respectively, at the following conditions – sodium alginate (3.55% w/v), alkaline extracted ispaghula husk (3.60% w/v), cross-linker concentration (7.82% w/v) and stirring speed (1200?rpm). The optimized formulation showed controlled drug release for more than 12?h by following Higuchi kinetics via non-Fickian diffusion. The gamma scintigraphy of the optimized formulation in Wistar rats showed that microparticles could be observed in the intestinal lumen after 1?h and were detectable in the intestine up to 12?h, with decreased percentage of radioactivity (t_1/2 of ^99mTc 4–5?h).     

Mössbauer spectroscopy indicates that iron in an aluminosilicate glass phase is the source of the bioavailable iron from coal fly ash

Iron speciation by M?ssbauer spectroscopy indicates that ferric iron in an aluminosilicate glass phase is the source of the bioavailable iron in coal fly ash and that this iron species is associated with combustion particles, but not with crustal dust derived from soil minerals. Urban particulate has been shown to be a source of bioavailable iron and has been shown to be able to induce the formation of reactive species in cell culture experiments. Crustal dust and laboratory-generated coal fly ash have been studied as surrogates for two sources of metal-bearing particles in ambient air. As much as a 60-fold difference in the amount of iron mobilized by the chelator citrate was observed between fly ash and crustal dust samples with similar total iron contents. The extent of iron mobilization by citrate in vitro has been shown to correlate with indirect measures of excess iron in cultured cells and with assays for reactive oxygen species generation in vitro. M?ssbauer spectroscopy of coal fly ash, before and after treatment with the chelator desferrioxamine B, showed that the iron in an aluminosilicate glass phase was preferentially removed. The removal of the glass-phase iron greatly reduced the amount of iron that could be mobilized by citrate and prevented the particles from inducing interleukin-8 in cultured human lung epithelial (A549) cells. Ferric iron in aluminosilicate glass is associated with particles formed at high temperatures followed by rapid cooling. The observation that ferric iron in aluminosilicate glass is the source of bioavailable iron in coal fly ash suggests that particles from ambient sources and other specific combustion sources should be examined for the presence of this potential source of bioavailable iron.     

Risk–benefit of antiemetics in prevention and treatment of chemotherapy-induced nausea and vomiting

The development of effective antiemetic prophylaxis is one of the most significant steps forward in the area of supportive care. Fifteen years ago, patients receiving chemotherapy had to face the fact that nausea and vomiting were inevitable adverse effects, which could only be partially prevented by treatment with antiemetics such as dopamine (DA) D2 receptor antagonists and corticosteroids. The first group of drugs specifically developed as antiemetics was the serotonin (5-hydroxytryptamine [5-HT]₃) receptor antagonists. These drugs have dramatically improved prophylaxis of chemotherapy-induced emesis, particularly when used in combination with a corticosteroid. This combination has resulted in a significant decrease in the number of patients vomiting, whereas the improvement in the prophylaxis of nausea has been less successful. Another group of antiemetics, the neurokinin (NK)₁ receptor antagonists, has recently been developed, and the first drug in this class, aprepitant, has been approved by the FDA and the EU authorities. Studies have showed that patients benefit from the use of this drug in combination with standard antiemetic therapy (5-HT₃ receptor antagonist plus a corticosteroid), both in the acute and delayed phase of nausea and vomiting induced by cisplatin-based chemotherapy. This development has not only led to improved efficacy but also to a decreased risk associated with the use of antiemetics. One of the problems with traditional antiemetics, for example, the DA D2 receptor antagonists, is the risk of unpleasant adverse effects including restlessness and dystonic reactions. To avoid these adverse effects, combination with benzodiazepines or antihistamines was necessary, often resulting in sedation. Modern research also includes pharmacogenomic investigations. This has led to speculation about the importance of drug–drug interactions involving antiemetics through competition for metabolism by the cytochrome P450 isoenzymes. The worst possible interaction would be a decrease in the effect of different cytotoxins but there is no evidence that such interactions are of importance in daily clinical practice. Guidelines are useful tools in the optimisation of antiemetic prophylaxis but, unfortunately, implementation of the evidence-based recommendations is far from successful. A prerequisite for further optimisation of antiemetic prophylaxis is updating of the guidelines, including recommendations for the use of NK₁ receptor antagonists (aprepitant), followed by implementation of these recommendations in the clinic. Future research must include ‘the difficult trials’ focusing on the remaining groups of patients with severe chemotherapy-induced nausea and vomiting, including patients with refractory and breakthrough emesis.     

Design,synthesis and bioevaluation of N-hydroxyquinolinones as potential anti-plasmodial,anti-bacterial and iron(Ⅱ)-chelating agents

OBJECTIVE To establish a small compound library via a versatile synthetic route for the investigation of natural-inspiring compounds containing N-hydroxypyridones motif as potential anti-plasmodial,anti-bacterial and iron(Ⅱ)-chelating agents.METHODS An amidation/cyclization approach was adopted to synthesize a library of N-hydroxyquinolinones.The anti-plasmodial susceptibility of lab clone 3D7 P.falciparum was measured using aprotocol modified from the WHO microtest.The minimum bactericidal concentration(MBC)values were determined against Escherichia coli and Staphylococcus arueus.Nine compounds were selected to test their iron(Ⅱ)-chelating abilities.The iron(Ⅱ)-chelating ability was determined by measuring the absorbance of ferrozine-iron complex at 562 nm.RESULTS A new route for the facile synthesis of a library of N-hydroxyquinolinones based on one-pot palladium catalyzed C-N amidation/dehydrocyclizationsequence was implemented.Four compounds show anti-plasmodial activities with the range of 1.1-1.4μmol·L-1,50% chelation abilities of the nine selected compounds were shown to be 0.24-0.29mmol·L-1.CONCLUSION Alibrary of N-hydroxyquinolinones was synthesized via a novel synthetic route.The anti-plasmodial and anti-bacterial activities of these compounds were evaluated.Four compounds show potent anti-plasmodial activities Nine compounds were examined for their propensities to undergo iron chelation and these compounds were shown to be promising iron(Ⅱ)chelators as compared to EDTA.     

Cardioprotective effects of an active metabolite of furnidipine in 2 models of isolated heart and on in vivo ischemia–induced and reperfusion-induced arrhythmias in rats

Dihydropyridines are known not only to have antiarrhythmic effects but also to exert a significant cardiac depressive influence. We previously showed that M-2, an active and final metabolite of furnidipine, had cardioprotective effects without the marked cardiac depression seen with this dihydropyridine. We studied the influence of M-2 infusion (10(-7) M) on hemodynamics during low-flow and regional ischemia in the rat working heart. We examined the protection conferred by M-2 infusion (10(-7) M) against effects of veratridine-induced intracellular calcium overload in the Langendorff heart. Additionally, we performed an in vivo study to explore the effects of oral administration of M-2 at different times and doses, in the ischemia- and reperfusion-induced arrhythmias model. M-2 improved coronary flow during low-flow and regional ischemia while favorably maintaining aortic pressure parameters. M-2 provided outstanding protection against deleterious effects of calcium overloading by significantly preventing rise in left ventricular diastolic pressure and decrease in coronary flow. M-2 reduced mortality and incidence and duration of severe arrhythmias while exhibiting differential influence on blood pressure, which depended on dose and time of administration and could suggest its clinical indication. The results of our entire study establish a beneficial cardioprotective role of M-2, which exhibited pleiotropic effects on the ischemic heart by imparting protection in various ways. This combined with good tolerance, long duration of action, low toxicity, and relatively large therapeutic window makes M-2 a promising candidate as a precursor for a new chemical class of cardioprotective drugs.     

Combination of α-glucosidase inhibitor and ribavirin for the treatment of dengue virus infection in vitro and in vivo

Cellular α-glucosidases I and II are enzymes that sequentially trim the three terminal glucoses in the N-linked oligosaccharides of viral envelope glycoproteins. This process is essential for the proper folding of viral glycoproteins and subsequent assembly of many enveloped viruses, including dengue virus (DENV). Imino sugars are substrate mimics of α-glucosidases I and II. In this report, we show that two oxygenated alkyl imino sugar derivatives, CM-9-78 and CM-10-18, are potent inhibitors of both α-glucosidases I and II in vitro and in treated animals, and efficiently inhibit DENV infection of cultured human cells. Pharmacokinetic studies reveal that both compounds are well tolerated at doses up to 100mg/kg in rats and have favorable pharmacokinetic properties and bioavailability in mice. Moreover, we showed that oral administration of either CM-9-78 or CM-10-18 reduces the peak viremia of DENV in mice. Interestingly, while treatment of DENV infected mice with ribavirin alone did not reduce the viremia, combination therapy of ribavirin with sub-effective dose of CM-10-18 demonstrated a significantly enhanced antiviral activity, as indicated by a profound reduction of the viremia. Our findings thus suggest that combination therapy of two broad-spectrum antiviral agents may provide a practically useful approach for the treatment of DENV infection.     

Different roles of PKC and PKA in effect of interferon-y on proliferation and collagen synthesis of fibroblasts

AIM: To study the signal roles of protein kinase C (PKC) and protein kinase A (PKA) in the influence of interferon-γ(IFN-γ) on proliferation and collagen synthesis of flbroblasts derived from hypertrophic scar (HS-FB) and normal skin (NS-FB). METHODS: HS-FB and NS-FB were cultured and passaged in Dulbecco's modified Eagle's medium (DMEM). Activity of PKC and PKA were assayed by transferring phosphorus (32P) into substrate after treatment with IFN-γ1000 kU/L at 10, 30, 60, and 120 min. Cell proliferation was determined with MTT assay. The collagen synthesis was measured with [3H]proline incorporation and Type Ⅲ pre-collagen was determined with radioimmunoassay. RESULTS: After exposure to IFN-γ1000 kU/L for 30 min, PKC activity of HS-FB and NS-FB increased from 2.57±0.14 and 2.13±0.12 nmol·min-1·g-1 of control to 3.75±0.19 and 3.36±0.16 nmol·min-1·g-1 respectively (P<0.05). After exposure to IFN-y 1000 kU/L for 60 and 120 min, PKA activities of HS-FB increased gradually from 0.82±0.04 nmol·m     

Expression and significance of IGF-Ⅱand VEGF in hepatocellular carcinoma

目的 检测肝癌(HCC)患者组织中IGF-Ⅱ、血管内皮生长因子 (VEGF)的表达及临床意义.方法 采用免疫组织化学染色方法 检测HCC及癌旁组织中IGF-Ⅱ、VEGF蛋白表达水平.结果 HCC及癌旁组织IGF-Ⅱ蛋白阳性表达率分别为55%(22/40)、12.5%(5/40),VEGF蛋白阳性表达率分别为62.5%(25/40)、12.5%(5/40),HCC组织中IGF-Ⅱ、VEGF蛋白表达均显著高于癌旁组织(P<0.05),且IGF-Ⅱ、VEGF表达呈明显正相关(r=0.59,P<0.05).IGF-Ⅱ、VEGF表达与患者的年龄、性别、肿瘤大小无关,但与肿瘤的组织学分级、是否侵及包膜及有无癌栓密切相关.结论 与癌旁组织比较,HCC组织中IGF-Ⅱ、VEGF呈现高表达,提示IGF-Ⅱ、VEGF参与了HCC的发生发展过程,可能与HCC的生长和增殖有关.