Preparation and Characterization of (5-Methyl-2-oxo-1,3-dioxol-4-yl) methyl Thiamine Sulfides

A new type of S-protected thiol-type thiamines (prodrugs), which have a (5-methyl-2-oxo-1,3-dioxol-4-yl) methyl group recognized as a biologically safe promoiety, were designed, prepared, and confirmed to show higher serum thiamine levels after oral administration to rats than after that of thiamine itself and bisbentiamin as standards. Thus it was shown that the promoiety should be also used for improvement of poor oral absorption of drugs with a mercapto group, in addition to the absorption of drugs with carboxyl, amino, and hydroxyl groups.

GW274150, a novel and highly selective inhibitor of the inducible isoform of nitric oxide synthase (iNOS), shows analgesic effects in rat models of inflammatory and neuropathic pain

Nitric oxide (NO), synthesised by different isoforms of nitric oxide synthase (NOS), has been linked with the development and maintenance of nociception. We studied the role of the inducible isoform, iNOS, in two different rat pain models with an inflammatory component. iNOS was immunohistochemically detected locally in the paw 6h after Freund's Complete Adjuvant (FCA) injection, showing a plateau at 24-72 h and falling slowly in the following weeks. This correlated with the late phase of the hypersensitivity to pain revealed in the behavioural tests. A highly selective iNOS inhibitor GW274150 (1-30 mg/kg orally, 24h after FCA) suppressed the accumulation of nitrite in the inflamed paw indicating substantial iNOS inhibition. At the same time it partially reversed FCA-induced hypersensitivity to pain and edema in a dose-dependent manner. After Chronic Constriction Injury (CCI) surgery to the sciatic nerve, iNOS presence was only detected locally in the region of the nerve (inflammatory cells). GW274150 (3-30 mg/kg orally, 21 days after surgery) also reversed significantly the CCI-associated hypersensitivity to pain. No iNOS was detectable in dorsal root ganglia, spinal cord or brain in either model. This study demonstrates a role for peripherally-expressed iNOS in pain conditions with an inflammatory component and the potential value of iNOS inhibitors in such conditions.

[A clinical pharmacokinetic study of multi-dose oral tetra-arsenic tetra-sulfide combination therapy in acute promyelocytic leukemia]

OBJECTIVE

To study the pharmacokinetics of multi-dose oral tetra-arsenic tetra-sulfide (As(4)S(4)) in acute promyelocytic leukemia (APL) patients and its major side effects.

METHODS

Clinical pharmacokinetic study of As(4)S(4) was carried out in 7 patients who had never used arsenic before. The total concentration of arsenic in blood, urine and hair was determined with hydride generation-atomic absorption spectrometry.

RESULTS

These patients were administrated oral As(4)S(4) complex capsule 20 mg/kg three times a day for 14 days. From day 10 and to day 14, the blood arsenic concentration and urinary arsenic excretion reached a steady state. The average minimal concentration (Cmin) and maximal concentration (Cmax) of blood arsenic was (53.3 +/- 9.0) microg/L and (70.7 +/- 10.8) microg/L. t 1/2 was prolonged to (70.7 +/- 31.7) hour, and area under curve (AUC) was (448.9 +/- 71.8) microg. h(-1).L(-1). Median time to peak concentration (Tmax) was 1 (range 0.5 - 8) hour. During As(4)S(4) therapy, 24-hour arsenic content in urine was (6170.8 +/- 3141.8) microg/L and it accounted for about (0.152 +/- 0.082)% of the total daily dosage. It decreased steadily over time after drug withdrawal, arsenic accumulated in hair and the concentration could be ten-fold higher than that before treatment.

CONCLUSION

Multi-dose oral As(4)S(4) is safe and has been relatively well tolerated in APL patients in spite of the tendency of its retention in some tissues after long time administration.

Inhibition or knock out of inducible nitric oxide synthase result in resistance to bleomycin-induced lung injury

BACKGROUND

In the present study, by comparing the responses in wild-type mice (WT) and mice lacking (KO) the inducible (or type 2) nitric oxide synthase (iNOS), we investigated the role played by iNOS in the development of on the lung injury caused by bleomycin administration. When compared to bleomycin-treated iNOSWT mice, iNOSKO mice, which had received bleomycin, exhibited a reduced degree of the (i) lost of body weight, (ii) mortality rate, (iii) infiltration of the lung with polymorphonuclear neutrophils (MPO activity), (iv) edema formation, (v) histological evidence of lung injury, (vi) lung collagen deposition and (vii) lung Transforming Growth Factor beta1 (TGF-beta1) expression.

METHODS

Mice subjected to intratracheal administration of bleomycin developed a significant lung injury. Immunohistochemical analysis for nitrotyrosine revealed a positive staining in lungs from bleomycin-treated iNOSWT mice.

RESULTS

The intensity and degree of nitrotyrosine staining was markedly reduced in tissue section from bleomycin-iNOSKO mice. Treatment of iNOSWT mice with of GW274150, a novel, potent and selective inhibitor of iNOS activity (5 mg/kg i.p.) also significantly attenuated all of the above indicators of lung damage and inflammation.

CONCLUSION

Taken together, our results clearly demonstrate that iNOS plays an important role in the lung injury induced by bleomycin in the mice.

Effects of 3-thia fatty acids on feed intake, growth, tissue fatty acid composition, beta-oxidation and Na+,K+-ATPase activity in Atlantic salmon

Atlantic salmon (Salmo salar) with an initial mass of 86 g were reared in 12 degrees C seawater for 8 weeks to a final average mass of 250 g. The fish were fed fish meal and fish oil-based diet supplemented with either 0%, 0.3% or 0.6% of tetradecylthioacetic acid (TTA), a 3-thia fatty acid. The specific growth rate (SGR) decreased with increasing dietary dose of TTA. The SGR of the group fed 0% of TTA (Control) was 1.8; that of the group fed 0.3% of TTA (TTA-L) was 1.7, and that of the group fed 0.6% of TTA (TTA-H) was 1.5. The mortality increased with increased dietary dose of TTA. The mitochondrial beta-oxidation capacity in the liver of fish fed the TTA diets was 1.5 to 2 times higher than that of the Control fish. TTA supplementation caused substantial changes in the fatty acid compositions of the phospholipids (PL), triacylglycerols (TAG) and free fatty acids (FFA) of gills, heart and liver. The percentages of n-3 fatty acids, particularly 22:6 n-3, increased in fish fed diets containing TTA, while the percentage of the saturated FAs 14:0 and 16:0 in the PL fractions of the gills and heart decreased. The sum of monounsaturated FAs in the PL and TAG fractions from liver was significantly higher in fish fed diets containing TTA. TTA itself was primarily incorporated into PL. Two catabolic products of TTA (sulphoxides of TTA) were identified, and these products were particularly abundant in the kidney. TTA supplementation had no significant effect on the activity of the membrane-bound enzyme Na(+),K(+)-ATPase.

[Realgar nano-particles induce apoptosis and necrosis in leukemia cell lines K562 and HL-60]

OBJECTIVE

To examine the growth-inhibitory, apoptosis- and necrosis-inducing effects of realgar nano-particles (RNP) in human chronic myelogenous leukemia cell line K562 and acute myeloid leukemia cell line HL-60, and to find out the chemical species with efficacy.

METHOD

A "solvent-relay" strategy was used for the preparation of RNP suspension. Cell viability was determined by MTT assay. Cell apoptosis and necrosis were characterized with Annexin V-PI double staining in association with flow cytometry and with morphological examination with Hoechst 33258 staining. Parallel experiments with arsenous acid (H3AsO3), the dominant form of arsenic trioxide in the solution, were conducted for comparison.

RESULT

The mean diameter of RNP was 159.0 nm. RNP showed growth-inhibitory effect on both cell lines. The double staining test indicated that RNP induced both apoptosis and necrosis, and this was further confirmed by morphological examination.

CONCLUSION

RNP induced both apoptosis and necrosis in leukemia cell lines K562 and HL-60. Thioarsenite species with both As-O and As-S bonds may be the active intermediates in the RNP.

Beneficial effects of a polar fraction of garlic (Allium sativum Linn) oil in rats fed with two different high fat diets

Feeding a diet containing 20% of sesame oil (SO) or coconut oil (CNO) along with 2% cholesterol to rats for two months showed differences in their serum and tissue lipid profile and certain enzyme activities. Hyperlipidemia and related oxidative effects were more pronounced in coconut oil fed rats than those fed sesame oil. Feeding a combination of the oils (10% CNO +10% SO) lowered significantly the hyperlipidemia and certain other deleterious effects of CNO. Feeding a polar fraction of garlic oil (PFGO) prepared in the same way as for ajoene and administered at a dosage of 100 mg/kg along with each of the above oil containing diets counteracted significantly the hyperlipidemic, oxidant and also most of the other deleterious effects of the oils like raised lipid levels in serum and tissues, raised serum levels of AST and tissue levels of HMGCoA reductase and the lowered serum and tissue levels of glutathione reductase. The results support the claims that ajoene, the major polar compound of garlic oil, has very good biological action, which warrants further study.

[Effects of allitridin on the expression of human cytomegalovirus immediate early antigens-IE72 and IE86 in human embryonic lung cells]

OBJECTIVE

To investigate the effect of allitridin injection on the expression of human cytomegalovirus (HCMV) immediate-early antigens (IEAs including IE72 and IE86) in human embryonic lung cells.

METHOD

HCMV AD 169 Virus strain infected cell model (MOI = 2.5 and 0.25, respectively) were established, and then treated with ICm5 and MTC doses of allitridin. Western blot was used to analyze the of IE72 and IE86 expression after the treatment, ganciclovir(GCV, IC50 and 2.3 x IC50) treatment as control.

RESULT

No matter what kind of MOI was used, both IE86 and IE72 antigens' expression was effectively suppressed by allitridin treatment, and the inhibitory rate of IE86 was almost twice of IE72's. Compared with GCV, allitridin had stronger inhibitory effect on IE86 expressing, although its efficacy on IE72 was weaker than GCV.

CONCLUSION

Allitridin could suppress the expression of IE72 and IE86, especially for IE86 expressing, maybe it is ore of key role in the mechanism of allitridin against HCMV.

Aged garlic extract, garlic powder extract, S-allylcysteine, diallyl sulfide and diallyl disulfide do not interfere with the antibiotic activity of gentamicin

It was shown that aged garlic extract (AGE), garlic powder and the following garlic-derived compounds: S-allylcysteine (SAC), diallyl sulfide (DAS) and diallyl disulfide (DADS), ameliorate gentamicin (GM)-induced nephrotoxicity in rats. However, it was not established if the above mentioned extracts and compounds of garlic could interfere with the antibiotic action of GM. To address this point, AGE, garlic powder extract (GPE), SAC, DAS and DADS were assessed for their ability to interfere with the in vitro antibiotic activity of GM in Escherichia coli cultures. It was found that the above mentioned extracts and compounds of garlic were unable to decrease the antibiotic capacity of GM and even SAC, DAS and DADS alone inhibited the growth of Escherichia coli and enhanced the antibiotic effect of GM. Our data show that SAC, DAS and DADS are antibacterial compounds against E. coli and suggest that AGE, GPE, SAC, DAS and[sol ]or DADS may be administered along with GM-treatment to ameliorate GM-induced nephrotoxicity without interfering with its antibiotic activity.

Modulation of p53 in 7,12-dimethylbenz[a]anthracene-induced skin tumors by diallyl sulfide in Swiss albino mice

Allium vegetables have been shown to have beneficial health effects against several chronic diseases including cancer. Diallyl sulfide (DAS), an organosulfur compound present in garlic, is well known for its chemopreventive properties in several tumor models. The pharmacologic role of DAS in prevention and treatment of cancer is well documented in the literature, but its molecular mechanism of action is not yet well defined. In the present study, modulation in p53 expression by topical application of DAS was recorded in 7,12-dimethylbenz[a]anthracene (DMBA)-induced skin tumors in Swiss albino mice. Western blot analysis and immunohistochemical protein detection, combined with multivariable flow cytometry, show that DAS application induces the expression of the wild-type (wt) p53 and down-regulates the expression of mutant (mut) p53. Immunoblotting analysis of tumors showed significant increase in levels of wtp53 by DAS application, whereas for mutp53 the DMBA-induced levels of protein were found to reduce to near normal levels with DAS application. The quantitative analysis of immunostained skin/tumor sections using image analysis and quantitative stereology showed 66.6% and 54.2% increases in wtp53 levels and 53.4% and 44.3% decreases in mutp53 levels in animals where DAS was applied 1 hour prior to or 1 hour after DMBA application, respectively. Flow cytometric analysis further confirmed modulation of wtp53 and mutp53 protein in DAS-supplemented tumors. The increase in the expression of wt tumor suppressor gene protein p53 was accompanied by elevation of the levels of cyclin-dependent kinase inhibitor p21/waf1. The percentage increase in the levels of p21/waf1 was found to be 72.9% and 61.3%, respectively, in DAS-supplemented groups before and after administration. These results thus show that DAS is a potential chemopreventive agent capable of modulating and regulating the tumor suppressor p53 along with its downstream effective molecule, p21/waf1. Thus, DAS can be a potential chemopreventive agent against skin tumor development.

An intervention study to prevent gastric cancer by micro-selenium and large dose of allitridum

BACKGROUND

People have more and more concerned about allitridum as studies have shown that taking more raw garlic associated with a lower risk for cancers of the alimentary system. In the present study, we tried to examine whether a large dose of allitridum and a microdose of selenium prevent gastric cancer.

METHODS

A double-blind intervention study was performed on the participants aged (35 - 74) years, who had matched at least one of the following criteria: (1) a medical history of stomach disorder, (2) a family history of tumour, or (3) smoking and/or alcohol consumption. A total of 2,526 and 2,507 persons were randomly enrolled into intervention group and control group respectively from 288 natural villages of seven communities in Qixia County, Shandong Province, China. Each person of the intervention group orally took 200 mg synthetic allitridum every day and 100 microg selenium every other day for one month of each year during November 1989 to December 1991. At the same time, people in control group were given 2 placebo capsules containing corn oid with the identical appearance to that in the intervention group.

RESULTS

For all subjects the large dose of allitridum was accepted and no harmful side effects were found during the study. In the first follow-up five years (1992 - 1997) after stopping the intervention, the morbidity rates of malignant tumours in the intervention group declined by 22%, in contrast to the control group, declined by 47.3%. After adjusting for age, gender, and other potential confounders, relative risks (RRs) for all tumours and gastric cancer of the whole population were 0.67 (95% CL: 0.43 - 1.03) and 0.48 (95% CL: 0.21 - 1.06), respectively, and for male group they were 0.51 (95% CL: 0.30 - 0.85) and 0.36 (95% CL: 0.14 - 0.92), respectively. No signigicantly protective effect was found for the female subgroup.

CONCLUSION

The present study proves that large doses of allitridum and microdorse of selenium may effectively prevent gastric cancer, especially in men.

[Electrophoresis of sulphide mud extract in combined therapy of chronic inflammatory diseases of uterine appendages (an experimental and clinical study)]

On the original experimental model of chronic inflammation of the ovaries and oviducts in white rats it was established that electrophoresis of 1% esobel solution prevents an increase in the specific volume of interstitial connective tissue, development of fibrosclerotic alterations and adhesive process. Peloidophysiotherapy normalizes growth and atresia of the ovarian follicular system. Thus, electrophoresis of 1% esobel solution is highly effective in combined treatment of chronic inflammatory diseases of the uterine appendages.

The effects of allyl sulfides on the induction of phase II detoxification enzymes and liver injury by carbon tetrachloride

Allyl sulfides, e.g., diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), are principal constituents of garlic oil. In the present study, we investigated the in vivo effect of these sulfides on the phase I and phase II drug-metabolizing enzymes, and elucidated their structure-function relationship. A highly purified form of each sulfide (more than 99% purity) was administered i.p. as a bolus to rats at a concentration of 10 or 100 micromol/kg body weight for 14 consecutive days. As to the phase I enzymes, DAS (100 micromol/kg) slightly but significantly increased cytochrome P-450 (CYP) 2E1 activity (1.6-fold vs. control), whereas DADS and DATS did not affect it or the hepatic total CYP level or CYP1A1/2 activity. With respect to the phase II enzymes, DATS (10 micromol/kg) and DADS at a 10-fold higher dose (100 micromol/kg) significantly increased the activities of glutathione S-transferase, quinone reductase, and antioxidative enzyme glutathione peroxidase; whereas DAS did not. In the carbon tetrachloride (CCl4)-induced acute liver injury model of rats, either DATS (10 micromol/kg) or DADS (100 micromol/kg) significantly reduced the injury caused by the induction of phase II enzymes with CCl4. In conclusion, the sulfides affected both phase I and phase II enzymes, the former being stimulated by the monosulfide only and the latter, strongly by the trisulfide and weakly by the disulfide. Therefore, the polysulfide DATS may be one of the important factors in garlic oil that protects our body against the injury caused by radical molecules encountered in daily life.

Treatment of dermatophytosis in dogs and cats: review of published studies

The recent literature on the treatment of dermatophytosis in dogs and cats was reviewed. Based upon in vitro studies using isolated infected hairs and controlled or field in vivo studies, the following topical treatments were consistently found to be antifungal (i.e. antidermatophyte): lime sulfur (1:16), 0.2% enilconazole rinses, and a combined 2% miconazole/chlorhexidine shampoo. Animals or hairs were either bathed or rinsed once or twice weekly. Itraconazole, griseofulvin and terbinafine were evaluated in controlled or field studies, most commonly involving cats. Griseofulvin (50 mg kg(-1)) was reported to cure infected animals in 41-70 days. Itraconazole (10 mg kg(-1) once daily or in a combined daily/pulse therapy 10 mg kg(-1) once daily for 28 days and then week on/week off) was reported to cure infected animals in 56-70 days. Low-dose itraconazole (1.5-3.0 mg kg(-1)) in 15-day cycles required 1-3 cycles (15-45 days). Various doses of terbinafine (5-40 mg kg(-1)) were reportedly used to treat dogs or cats. The higher doses of terbinafine (> 20 mg kg(-1)) were required to achieve a mycological cure; the number of treatment days to cure varied from 21 to > 126 days. Lufenuron was reported anecdotally to be an effective cure, however, this was not substantiated in controlled studies. Finally, fungal vaccines were not found to be effective against challenge exposure, however, there is evidence that they may be useful in treatment protocols.

Experimental study on the prevention and treatment of murine cytomegalovirus hepatitis by using allitridin

Allitridin (diallyl trisulfide), a main effective compound of Allium sativum (garlic), was previously shown to inhibit the expression of immediate-early antigens and viral proliferation of human cytomegalovirus (HCMV) in vitro. Here we have examined the prophylactic and therapeutic efficacy of allitridin in a non-lethal murine cytomegalovirus (MCMV) hepatitis in methylprednisolone-immunosuppressed BALB/c mice. Allitridin was administered at 25mg/kg per day (equal to the mean human dose) and 75 mg/kg per day in two regimens: prophylaxis plus therapy beginning at 2 days before infection and lasting for 18 days, and therapy lasting for 14 days initiated at 2 days after infection. Ganciclovir (GCV)-treated, infected, and non-infected mice served as controls. MCMV DNA load in the liver, plasma alanine aminotransferase (ALT) level and Knodell's histological activity index (HAI) score of liver section were evaluated. We found that MCMV DNA load was significantly decreased in all allitridin- and GCV-treated mice, compared with infected controls. Concomitantly, histopathological lesions in the liver and plasma ALT levels were reduced. Statistically, no significant differences were detected between the combined allitridin prophylaxis plus therapeutic and therapeutic groups regardless of dose and the GCV groups. Our results demonstrate the therapeutic efficacy of allitridin in mouse models with MCMV hepatitis.

[Changes of endogenous hydrogen sulfide (H2S) in hypertensive rats]

OBJECTIVE

Hydrogen sulfide, a well known toxic gas, has been found to play important roles in many organs and tissues, especially in cardiovascular system recently. The aim of this study was to explore the producing rate of hydrogen sulfide (H(2)S) in aorta and the level of H(2)S in plasma of spontaneous hypertensive rats (SHR), and to study the role of H(2)S on the development of hypertension.

METHODS

Twenty-four male SHR rats at the age of 4 weeks were randomly divided into SHR control group, SHR + NaHS (H(2)S donor) group and SHR + DL-propargylglycine (PPG) group, respectively. Another twenty-four male WKY rats were also divided into WKY control group, WKY + NaHS group and WKY + PPG group. SHR control and WKY control rats were injected with water. Rats of SHR + NaHS group and WKY + NaHS group were injected with NaHS, and rats of SHR + PPG group and WKY + PPG group were injected with PPG every day. Five weeks later, the blood pressure and the left-to-whole heart weight ratio were determined. The producing rate of H(2)S in aorta and the H(2)S level in plasma were also detected.

RESULTS

The producing rate of H(2)S in aorta and the plasma level of H(2)S in SHR groups were all less than those of the corresponding WKY groups, however, the differences between SHR + PPG group and WKY + PPG group were not significant (P > 0.05). The producing rate of H(2)S and the plasma level of H(2)S in SHR + PPG group were similar to those of SHR control group. The producing rate of H(2)S and the plasma level of H(2)S in SHR + NaHS group were higher than those of SHR control. Both the producing rate and the plasma level of H(2)S in WKY + PPG group were less than those of WKY control. The producing rate of H(2)S in aorta of WKY + NaHS group was higher than that of WKY controls, while the plasma level of H(2)S in WKY + NaHS group was not different from that of WKY controls significantly. The blood pressure of SHR groups increased compared with that of WKY groups (P < 0.05). The blood pressure of SHR + PPG group was similar to that of SHR controls, while the blood pressure of SHR + NaHS reduced significantly compared with that of SHR controls. The blood pressure of WKY + PPG group was higher than that of WKY controls while the blood pressure of WKY + NaHS was similar to that of WKY controsl.

CONCLUSIONS

H(2)S plays an important role in maintaining normal pressure and the reduced production of endogenous H(2)S is an essential factor in the development of spontaneous hypertension. Exogenous H(2)S provides a new way for interfering with the progression of hypertension.

Inhibition of N-acetyltransferase activity and gene expression in human colon cancer cell lines by diallyl sulfide

Diallyl sulfide (DAS) is one of the major components of garlic (Allium sativum) and is widely used in the world for food. In this study, DAS was selected for testing the inhibition of arylamine N-acetyltransferase (NAT) activity (N-acetylation of 2-aminofluorene) and gene expression (mRNA NAT) in human colon cancer cell lines (colo 205, colo 320 DM and colo 320 HSR). The NAT activity was examined by high performance liquid chromatography and indicated that a 24 h DAS treatment decreases N-acetylation of 2-aminofluorene in three colon (colo 205, 320 DM and colo 320 HSR) cancer cell lines. The NAT enzymes (protein) were analyzed by western blotting and flow cytometry and it indicated that DAS decreased the levels of NAT in three colon (colo 205, 320 DM and colo 320 HSR) cancer cell lines. The gene expression of NAT (mRNAT NAT) was determined by polymerase chain reaction (PCR), it was shown that DAS affect mRNA NAT expression in examined human colon cancer cell lines. This report is the first to demonstrate that DAS does inhibit human colon cancer cell NAT activity and gene expression.

[Vibrophoresis of mud lipid extract in the rehabilitation of patients with osteoarthrosis]

Experimental and clinical evidence (76 patients with osteoarthrosis) justifies combined use of thermovibration massage and lipid extract from therapeutic mud eplir. This combination produces analgetic, antiedematic, antiinflammatory actions and promotes normalization of systemic immunity and peripheral hemodynamics.

Less common methods to treat acne

Effective medications to treat acne sometimes become unavailable in certain countries, either for economic reasons or for shortage of them in the pharmaceutical market. The purpose of this report is to review a series of drugs of topical and systemic use; some old and some new. The topical group includes agents such as sulfur, salicylic acid and the alpha-hydroxy acids, while the systemic group includes diaminodiphenylsulfone, clofazimine, ibuprofen and others. Some presumably useful physical methodologies and the recent findings in phototherapy, particularly the properties of blue light and blue-red light, are also reviewed. Finally, we report on the results obtained from the combined use of isotretinoin and methylprednisone in severe inflammatory acne, to prevent a possible triggering of the 'pseudo' acne fulminans.

Effects of garlic components diallyl sulfide and diallyl disulfide on arylamine N-acetyltransferase activity and 2-aminofluorene-DNA adducts in human promyelocytic leukemia cells

Two components of garlic, diallyl sulfide (DAS) and diallyl disulfide (DADS), inhibited arylamine N-acetyltransferase (NAT) activity and 2-aminofluorene-DNA adduct in human promyelocytic leukemia cells (HL-60). The NAT activity was measured by high performance liquid chromatography assaying for amounts of N-acetyl-2-aminofluorene (2-AAF) and remaining 2-aminofluorene (2-AF). Cellular cytosols and intact cell suspensions were assayed. The inhibition of NAT activity and 2-AF-DNA adduct formation in human leukemia cells by DAS and DADS were dose-dependent and were directly proportional. The data also indicated that DAS and DADS decrease the apparent values of Km and Vmax from human leukemia cells in both assays. This is the first report of garlic components affecting human leukemia cell NAT activity and 2-AF-DNA adduct formation.

A mesoporous silica nanosphere-based carrier system with chemically removable CdS nanoparticle caps for stimuli-responsive controlled release of neurotransmitters and drug molecules

An MCM-41 type mesoporous silica nanosphere-based (MSN) controlled-release delivery system has been synthesized and characterized using surface-derivatized cadmium sulfide (CdS) nanocrystals as chemically removable caps to encapsulate several pharmaceutical drug molecules and neurotransmitters inside the organically functionalized MSN mesoporous framework. We studied the stimuli-responsive release profiles of vancomycin- and adenosine triphosphate (ATP)-loaded MSN delivery systems by using disulfide bond-reducing molecules, such as dithiothreitol (DTT) and mercaptoethanol (ME), as release triggers. The biocompatibility and delivery efficiency of the MSN system with neuroglial cells (astrocytes) in vitro were demonstrated. In contrast to many current delivery systems, the molecules of interest were encapsulated inside the porous framework of the MSN not by adsorption or sol-gel types of entrapment but by capping the openings of the mesoporous channels with size-defined CdS nanoparticles to physically block the drugs/neurotransmitters of certain sizes from leaching out. We envision that this new MSN system could play a significant role in developing new generations of site-selective, controlled-release delivery nanodevices.

Fasting stress exacerbates classical conditioned histamine release in guinea pigs

To clarify the contribution of stress to classical conditioning-associated asthmatic responses, the effect of fasting stress on conditioned histamine release was investigated in a guinea pig model of asthma. The animals were randomly divided into 2 groups for Experiment 1 and 2, and received a conditioning procedure in which ovalbumin (OA) as an unconditioned stimulus (US) and dimethylsulfide (DMS, sulfur smelling) as a conditioned stimulus (CS) were simultaneously inhaled after fasting for 16 h. Then, one group was given food as a reward for respiratory distress, and the other group was denied it for more than 3 h, while being placed in front of the feeding group. After this procedure was repeated 5 times, the plasma histamine levels in response to the CS were measured in half of each group in Experiment 1, and the respiratory resistance (Rrs) was assessed similarly in the other half of each group in Experiment 2. The same experiments were again performed after exchanging assignments of feeding group or fasting group in both experiments. The control groups in both experiments received the CS and the US 10 times separately in a random order under 16 h fasting conditions and were provided food after the exposures. After these pseudo-conditioning presentations, the plasma histamine levels or the Rrs in response to the CS were measured. In Experiment 1, the plasma histamine levels in the fasting stress group after the first conditioning sessions were significantly higher than those of the other groups. This difference was not observed when the groups were exchanged. In Experiment 2, the fasting stress group showed higher values in the Rrs compared to the other groups, irrespective of the first or second conditionings; however, they were not significant. The present study indicates that fasting stress after the conditioning procedures exacerbates the following conditioned histamine release, although the stress effect on bronchoconstriction was not confirmed.

H(2)S-induced vasorelaxation and underlying cellular and molecular mechanisms

H(2)S is endogenously generated in vascular smooth muscle cells. The signal transduction pathways involved in the vascular effects of H(2)S have been unclear and were investigated in the present study. H(2)S induced a concentration-dependent relaxation of rat aortic tissues that was not affected by vascular denervation. The vasorelaxant potency of H(2)S was attenuated by the removal of the endothelium. Similarly, the blockade of nitric oxide synthase or the coapplication of the Ca(2+)-dependent K(+) channel blockers apamin and charybdotoxin reduced the H(2)S-induced relaxation of the endothelium-intact aortic tissues. Sodium nitroprusside (SNP)-induced relaxation was completely abolished by either 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) or NS- 2028, two soluble guanylate cyclase inhibitors. Instead of inhibition, ODQ and NS-2028 potentiated the H(2)S-induced vasorelaxation, which was suppressed by superoxide dismutase. The vasorelaxant effect of H(2)S was also significantly attenuated when Ca(2+)-free bath solution was used. Finally, pretreatment of aortic tissues with H(2)S reduced the relaxant response of vascular tissues to SNP. Our results demonstrate that the vascular effect of H(2)S is partially mediated by a functional endothelium and dependent on the extracellular calcium entry but independent of the activation of the cGMP pathway.