Arsenic Secondary Methylation Capacity Is Inversely Associated with Arsenic Exposure-Related Muscle Mass Reduction

Skeletal muscle mass reduction has been implicated in insulin resistance (IR) that promotes cardiometabolic diseases. We have previously reported that arsenic exposure increases IR concomitantly with the reduction of skeletal muscle mass among individuals exposed to arsenic. The arsenic methylation capacity is linked to the susceptibility to some arsenic exposure-related diseases. However, it remains unknown whether the arsenic methylation capacity affects the arsenic-induced reduction of muscle mass and elevation of IR. Therefore, this study examined the associations between the arsenic methylation status and skeletal muscle mass measures with regard to IR by recruiting 437 participants from low- and high-arsenic exposure areas in Bangladesh. The subjects' skeletal muscle mass was estimated by their lean body mass (LBM) and serum creatinine levels. Subjects' drinking water arsenic concentrations were positively associated with total urinary arsenic concentrations and the percentages of MMA, as well as inversely associated with the percentages of DMA and the secondary methylation index (SMI). Subjects' LBM and serum creatinine levels were positively associated with the percentage of DMA and SMI, as well as inversely associated with the percentage of MMA. HOMA-IR showed an inverse association with SMI, with a confounding effect of sex. Our results suggest that reduced secondary methylation capacity is involved in the arsenic-induced skeletal muscle loss that may be implicated in arsenic-induced IR and cardiometabolic diseases.

Higher risk of hyperglycemia with greater susceptibility in females in chronic arsenic-exposed individuals in Bangladesh

Arsenic (As) toxicity and diabetes mellitus (DM) are emerging public health concerns worldwide. Although exposure to high levels of As has been associated with DM, whether there is also an association between low and moderate As exposure and DM remains unclear. We explored the dose-dependent association between As exposure levels and hyperglycemia, with special consideration of the impact of demographic variables, in 641 subjects from rural Bangladesh. The total study participants were divided into three groups depending on their levels of exposure to As in drinking water (low, moderate and high exposure groups). Prevalence of hyperglycemia, including impaired glucose tolerance (IGT) and DM was significantly associated with the subjects' drinking water arsenic levels. Almost all exposure metrics (As levels in the subjects' drinking water, hair and nails) showed dose-dependent associations with the risk of hyperglycemia, IGT and DM. Among the variables considered, sex, age, and BMI were found to be associated with higher risk of hyperglycemia, IGT and DM. In sex-stratified analyses, As exposure showed a clearer pattern of dose-dependent risk for hyperglycemia in females than males. Finally, drinking water containing low-to-moderate levels of As (50.01-150 μg/L) was found to confer a greater risk of hyperglycemia than safe drinking water (As ≤10 μg/L). Thus the results suggested that As exposure was dose-dependently associated with hyperglycemia, especially in females.

Diversity of Secondary Metabolites in the Liverwort Syzygiella rubricaulis (Nees) Stephani (Jamesoniellaceae, Marchantiophyta) from Neotropical High Mountains

In order to evaluate the chemical diversity of Syzygiella rubricaulis (Nees) Stephani, a species with a disjunct distribution in the neotropical high mountains, a phytochemical study was carried out with samples from 12 different populations of different altitudes from four South American countries. The chemical profiles of lipophilic extracts were analyzed by GC/MS for each population and 50 different compounds were found with the predominance and richness of sesquiterpenes. The majority of the compounds were found only in one population and the total number of substances ranged from 1 to 15 among the populations, but these numbers were not correlated with altitude, and characterize each population as distinct, based on similarity analysis. The qualitative and quantitative variations of metabolites found are a response to different conditions, under which they live, mostly likely altitudinal conditions. Further studies on the quantification of these chemicals may provide information on their ecological roles and importance for the distribution of S. rubricaulis at different altitudes. Despite the known richness of secondary metabolites produced by bryophytes, they are still poorly explored in the context of the ecological expressions.

Association between arsenic exposure and soluble thrombomodulin: A cross sectional study in Bangladesh

Chronic exposure to arsenic is associated with increased morbidity and mortality from cardiovascular disease (CVD); however, plausible biomarker for early prediction and the underlying mechanism of arsenic-related CVD have not yet been clearly understood. Endothelial dysfunction plays a central role in the development of CVD. We hypothesized that endothelial damage or dysfunction is an important aspect and may be an early event of arsenic-related CVD. Soluble thrombomodulin (sTM) in serum is thought to be a specific and stable marker for endothelial damage or dysfunction. This study was designed to evaluate the association between chronic exposure to arsenic and sTM among human subjects in arsenic-endemic and non-endemic rural areas in Bangladesh. A total of 321 study subjects (217 from arsenic-endemic areas and 104 from a non-endemic area) were recruited. Subjects' arsenic exposure levels (i.e., drinking water, hair and nail arsenic concentrations) were measured by Inductively Coupled Plasma Mass Spectroscopy. The subjects' serum sTM levels were quantified by immunoassay kit. The average sTM levels of the subjects in arsenic-endemic and non-endemic areas were 4.58 ± 2.20 and 2.84 ± 1.29 (ng mL-1) respectively, and the difference was significant (p<0.001). Arsenic exposure levels showed a significant (water arsenic: rs = 0.339, p<0.001, hair arsenic: rs = 0.352, p<0.001 and nail arsenic: rs = 0.308, p<0.001) positive associations with sTM levels. Soluble TM levels were higher in the higher exposure gradients if we stratified the subjects into tertile groups (low, medium and high) based on the arsenic concentrations of the subjects' drinking water, hair and nails. Finally, increased levels of sTM were negatively correlated with high density lipoprotein cholesterol (HDL-C), and positively correlated with intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Results of this study show that chronic exposure to arsenic has mild to moderate association with sTM levels.

Chronic exposure to arsenic, LINE-1 hypomethylation, and blood pressure: a cross-sectional study in Bangladesh

BACKGROUND

Chronic exposure to arsenic is associated with cancer and hypertension. Growing evidence suggests that altered methylation in long interspersed nuclear element-1 (LINE-1) is involved in many types of disorders, including cardiovascular disease. Here we evaluated the association between arsenic exposure and LINE-1 methylation levels, especially in relation to blood pressure (BP).

METHODS

A total of 236 subjects (175 from arsenic-endemic areas and 61 from a non-endemic area) in rural Bangladesh were recruited. The subjects' arsenic exposure levels (i.e., drinking water, hair and nail arsenic concentrations) were measured by inductively coupled plasma mass spectroscopy. The subjects' LINE-1 methylation levels were determined by pyrosequencing.

RESULTS

The average LINE-1 methylation levels of the subjects living in the arsenic-endemic areas were significantly (p < 0.01) lower than those of the subjects living in the non-endemic area. In a sex-stratified analysis, the arsenic exposure levels in female but not male subjects showed a significant inverse association with LINE-1 methylation levels before (water arsenic: p < 0.01, hair arsenic: p < 0.05, nail arsenic: p < 0.001) and after (water arsenic: p < 0.01, hair arsenic: p < 0.05, nail arsenic: p < 0.001) adjustment for age, body mass index and smoking. Analyses examining interactions among arsenic levels, BP and LINE-1 methylation showed that arsenic-related elevated levels of BP were associated with LINE-1 hypomethylation.

CONCLUSIONS

Our findings demonstrated that chronic exposure to arsenic was inversely associated with LINE-1 methylation levels in blood leukocyte DNA and this was more pronounced in females than males; in addition, the decreased levels of LINE-1 methylation might be involved in the arsenic-induced elevation of BP.

Assessment of metal and bacterial contamination in cultivated fish and impact on human health for residents living in the Mekong Delta

Fish is the main source of animal protein and micronutrients for inhabitants in the lower Mekong River basin. Consumption of fish in the basin ranges from 41 to 51 kg capita(-1) year(-1). Thus, concerns of human health impacts caused by daily intake of metals contained in fish, and the incidence of bacterial contamination from Listeria and Escherichia coli have been raised. This study was conducted to 1) determine concentrations of metals, fecal indicator organisms, and Listeria spp. in cultivated common diet fish, and 2) assess human health risks as results of fish consumption on a daily basis. The results showed significant impacts of metal accumulation in fish especially from the intensive aquaculture. Chemical use to promote the rapid allometric growth of fish was expected to be the explanation for this finding. Concentrations of metals contained in different fish species were not statistically different with the exceptions of Na, Mn, and Zn. This might be due to the mobility of elements in aquaculture farms. Listeria and E. coli log CFU/g were 1.36 ± 0.11 (standard error) and 1.57 ± 0.1 s.e., respectively with higher counts observed in samples collected in market sites. Lastly, for human health risk assessment via fish consumption, it was found that hazard quotients of consuming As, Cu, and Zn contained in all fish species could contribute adverse health effects to the local residents (hazard quotients higher than 1). Therefore, risk management measures must be promoted and implemented in all study areas to reduce potential risks to local Vietnamese residents.

Dietary intake of metals by the young adult population of Eastern Poland: Results from a market basket study

Dietary intake of macro-, trace and toxic elements was determined among the young adult population of Eastern Poland. The study was performed in 2011-2013 and involved 583 participants living in Lublin and its province. Dietary intakes of metals were determined using a 24h dietary recall technique and a market basket method. The analytical quantification of As, Ca, Cd, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Se and Zn was performed using ICP-MS technique, whereas the content of mercury was determined using the Mercury Analyzer. Performed investigations revealed that daily dietary intakes of the majority of the study elements (macro- and trace) and toxic elements such as As, Pb or Hg are within the range of reference values. However, high consumption of Na and improper Na/K ratio combined with low intake of Mg may be harmful to the health of the population. Moreover, obtained data suggest that the risk of developing diseases among population in Eastern Poland related to high exposure to Ni and Cd absorbed from foodstuffs was high.

Elevated concentrations of serum matrix metalloproteinase-2 and -9 and their associations with circulating markers of cardiovascular diseases in chronic arsenic-exposed individuals

BACKGROUND

Cardiovascular diseases (CVDs) and cancers are the major causes of chronic arsenic exposure-related morbidity and mortality. Matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) are deeply involved in the pathogenesis of CVDs and cancers. This study has been designed to evaluate the interactions of arsenic exposure with serum MMP-2 and MMP-9 concentrations especially in relation to the circulating biomarkers of CVDs.

METHODS

A total of 373 human subjects, 265 from arsenic-endemic and 108 from non-endemic areas in Bangladesh were recruited for this study. Arsenic concentrations in the specimens were measured by inductively coupled plasma mass spectroscopy (ICP-MS) and serum MMPs were quantified by immunoassay kits.

RESULTS

Serum MMP-2 and MMP-9 concentrations in arsenic-endemic population were significantly (p < 0.001) higher than those in non-endemic population. Both MMPs showed significant positive interactions with drinking water (r s  = 0.208, p < 0.001 for MMP-2; r s  = 0.163, p < 0.01 for MMP-9), hair (r s  = 0.163, p < 0.01 for MMP-2; r s  = 0.173, p < 0.01 for MMP-9) and nail (r s  = 0.160, p < 0.01 for MMP-2; r s  = 0.182, p < 0.001 for MMP-9) arsenic of the study subjects. MMP-2 concentrations were 1.02, 1.03 and 1.05 times, and MMP-9 concentrations were 1.03, 1.06 and 1.07 times greater for 1 unit increase in log-transformed water, hair and nail arsenic concentrations, respectively, after adjusting for covariates (age, sex, BMI, smoking habit and hypertension). Furthermore, both MMPs were increased dose-dependently when the study subjects were split into three (≤10, 10.1-50 and > 50 μg/L) groups based on the regulatory upper limit of water arsenic concentration set by WHO and Bangladesh Government. MMPs were also found to be significantly (p < 0.05) associated with each other. Finally, the concentrations of both MMPs were correlated with several circulating markers related to CVDs.

CONCLUSIONS

This study showed the significant positive associations and dose-response relationships of arsenic exposure with serum MMP-2 and MMP-9 concentrations. This study also showed the interactions of MMP-2 and MMP-9 concentrations with the circulating markers of CVDs suggesting the MMP-2 and MMP-9 -mediated mechanism of arsenic-induced CVDs.

Synergistic augmentation of ATP-induced interleukin-6 production by arsenite in HaCaT cells

Chronic arsenic exposure causes cutaneous diseases such as hyperkeratosis and skin cancer. However, little information has been available regarding the molecular mechanisms underlying these symptoms. Because extracellular ATP and interleukin-6 (IL-6) are involved in pathological aspects of cutaneous diseases, we examined whether sodium arsenite (As(III)) affects ATP-induced IL-6 production in human epidermal keratinocyte HaCaT cells. The results showed that the addition of As(III) into the medium of HaCaT cells dose dependently increased the production of IL-6 induced by extracellular ATP, although As(III) alone had no effect on IL-6 production. To elucidate the mechanism of the synergistic effect of As(III) on IL-6 production by extracellular ATP, we next examined the phosphorylation of p38, ERK and epidermal growth factor receptor (EGFR), since we found that these signaling molecules were stimulated by exposure to extracellular ATP. The results indicated that ATP-induced phosphorylation of p38, ERK and EGFR was synergistically enhanced by co-exposure to As(III). To clarify the mechanisms underlying the enhanced phosphorylation of p38, ERK and EGFR by As(III), we explored two possible mechanisms: the inhibition of extracellular ATP degradation and the inhibition of protein tyrosine phosphatases (PTPs) activity by As(III). The degradation of extracellular ATP was not changed by As(III), whereas the activity of PTPs was significantly inhibited by As(III). Our results suggest that As(III) augments ATP-induced IL-6 production in HaCaT cells through enhanced phosphorylation of the EGFR and p38/ERK pathways, which is associated with the inhibition of PTPs activity.

Associations of total arsenic in drinking water, hair and nails with serum vascular endothelial growth factor in arsenic-endemic individuals in Bangladesh

Arsenic exposure is associated with cancer and vascular diseases. Angiogenesis is an important step for the pathological development of cancer and vascular diseases. Vascular endothelial growth factor (VEGF) is a specific marker for angiogenesis. However, human study showing the association between arsenic exposure and serum VEGF levels has not yet been documented. This study was aimed to investigate the association between arsenic exposure and serum VEGF levels in the arsenic-endemic individuals in Bangladesh. A total of 260 individuals were recruited for this study. Arsenic exposure levels were measured by ICP-MS and VEGF levels were quantified using VEGF immunoassay kit. The study subjects were stratified into tertile (low, medium and high) groups based on the arsenic in water, hair and nails. Serum VEGF levels were correlated with water (rs = 0.363, p < 0.001), hair (rs = 0.205, p < 0.01) and nail (rs = 0.190, p < 0.01) arsenic. Further, VEGF levels showed dose-response relationships with water, hair and nail arsenic. Mean VEGF levels in ⩽ 10 μg L(-1), 10.1-50 μg L(-1) and > 50 μg L(-1) groups were 91.84, 129.54, and 169.86 pg mL(-1), respectively, however, significant (p < 0.01) difference in VEGF levels was only found in > 50 μg L(-1) versus ⩽ 10 μg L(-1) groups. Significant associations of arsenic exposure with VEGF levels were found even after adjusting with relevant covariates. Therefore, these results provide evidence that arsenic exposure has a pro-angiogenic effect on humans, which may be implicated in arsenic-induced tumorigenesis and vascular diseases.

A heterogeneous mercury salt catalyst stabilized by m-carbaborane

A novel hetergeneous mercury salt catalyst stabilized by m-carbaborane can be used and reused for various chemical reactions without leaching the metal.

Elevated levels of plasma uric acid and its relation to hypertension in arsenic-endemic human individuals in Bangladesh

Blood uric acid has been recognized as a putative marker for cardiovascular diseases (CVDs). CVDs are the major causes of arsenic-related morbidity and mortality. However, the association of arsenic exposure with plasma uric acid (PUA) levels in relation to CVDs has not yet been explored. This study for the first time demonstrated the associations of arsenic exposure with PUA levels and its relationship with hypertension. A total of 483 subjects, 322 from arsenic-endemic and 161 from non-endemic areas in Bangladesh were recruited as study subjects. Arsenic concentrations in the drinking water, hair and nails of the study subjects were measured by inductively coupled plasma mass spectroscopy. PUA levels were measured using a colorimetric method. We found that PUA levels were significantly (p<0.001) higher in males and females living in arsenic-endemic areas than those in non-endemic area. Arsenic exposure (water, hair and nail arsenic) levels showed significant positive correlations with PUA levels. In multiple regression analyses, arsenic exposure levels were found to be the most significant contributors on PUA levels among the other variables that included age, body mass index, blood urea nitrogen, and smoking. There were dose-response relationships between arsenic exposure and PUA levels. Furthermore, diastolic and systolic blood pressure showed significant positive correlations with PUA levels. Finally, the average PUA levels were significantly higher in the hypertensive group than those in the normotensive group in both males and females living in arsenic-endemic areas. These results suggest that arsenic exposure-related elevation of PUA levels may be implicated in arsenic-induced CVDs.

An integrative study of the genetic, social and environmental determinants of chronic kidney disease characterized by tubulointerstitial damages in the North Central Region of Sri Lanka

OBJECTIVES

Previous investigations on chronic kidney disease of unknown etiology characterized by tubulointerstitial damages (CKDu) in the North Central Region (NCR) of Sri Lanka have supported the involvement of social, environmental and genetic factors in its pathogenesis.

METHODS

We conducted a social-environmental-and-genetic epidemiology study on a male population in NCR to investigate the genetic and environmental contributors. We recruited 311 case-series patients and 504 control candidates. Of the 504 control candidates, 218 (43%) were eliminated because of the presence of hypertension, proteinuria, high HbA1c, high serum creatinine or high alpha-1 microglobulin in urine.

RESULTS AND DISCUSSION

None of 18 metals measured (μg//) in urine, including Cd, As and Pb, showed significantly higher concentrations in cases compared with controls. As speciation results showed that 75-80% of total urinary As was in the form of arsenobetaine, which is non-toxic to humans. None of the metal concentrations in drinking water samples exceeded guideline values. A genome-wide association study (GWAS) was conducted to determine the genetic contributors. The GWAS yielded a genome-wide significant association with CKDu for a single nucleotide polymorphism (SNP; rs6066043; p=5.23 × 10(-9) in quantitative trait locus analysis; p=3.73 × 10(-9) in dichotomous analysis) in SLC13A3 (sodium-dependent dicarboxylate transporter member 3). The population attributable fraction and odds ratio for this SNP were 50% and 2.13. Genetic susceptibility was identified as the major risk factor for CKDu. However, 43% of the apparently healthy male population suffers from non-communicable diseases, suggesting their possible influence on CKDu progression.

Dose-response relationship between arsenic exposure and the serum enzymes for liver function tests in the individuals exposed to arsenic: a cross sectional study in Bangladesh

BACKGROUND

Chronic arsenic exposure has been shown to cause liver damage. However, serum hepatic enzyme activity as recognized on liver function tests (LFTs) showing a dose-response relationship with arsenic exposure has not yet been clearly documented. The aim of our study was to investigate the dose-response relationship between arsenic exposure and major serum enzyme marker activity associated with LFTs in the population living in arsenic-endemic areas in Bangladesh.

METHODS

A total of 200 residents living in arsenic-endemic areas in Bangladesh were selected as study subjects. Arsenic concentrations in the drinking water, hair and nails were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The study subjects were stratified into quartile groups as follows, based on concentrations of arsenic in the drinking water, as well as in subjects' hair and nails: lowest, low, medium and high. The serum hepatic enzyme activities of alkaline phosphatase (ALP), aspartate transaminase (AST) and alanine transaminase (ALT) were then assayed.

RESULTS

Arsenic concentrations in the subjects' hair and nails were positively correlated with arsenic levels in the drinking water. As regards the exposure-response relationship with arsenic in the drinking water, the respective activities of ALP, AST and ALT were found to be significantly increased in the high-exposure groups compared to the lowest-exposure groups before and after adjustments were made for different covariates. With internal exposure markers (arsenic in hair and nails), the ALP, AST and ALT activity profiles assumed a similar shape of dose-response relationship, with very few differences seen in the higher groups compared to the lowest group, most likely due to the temporalities of exposure metrics.

CONCLUSIONS

The present study demonstrated that arsenic concentrations in the drinking water were strongly correlated with arsenic concentrations in the subjects' hair and nails. Further, this study revealed a novel exposure- and dose- response relationship between arsenic exposure metrics and serum hepatic enzyme activity. Elevated serum hepatic enzyme activities in the higher exposure gradients provided new insights into arsenic-induced liver toxicity that might be helpful for the early prognosis of arsenic-induced liver diseases.

Interaction between chronic arsenic exposure via drinking water and plasma lactate dehydrogenase activity

Arsenic is a potent environmental pollutant that has caused one of the largest public health poisonings in the history of human civilization, affecting tens of millions of people worldwide especially in Bangladesh. Lactate dehydrogenase (LDH) in blood plays an important role in predicting cell or organ damage and as an important clue to the diagnosis of a variety of cancers. However, effect of chronic arsenic exposure on the LDH level in blood has not yet been documented. Since the chronic arsenic exposure is associated with organ damages and multi-site cancers, this research aimed at assaying the plasma level of LDH activity in the population who were exposed to arsenic chronically in Bangladesh. A total of 185 individuals living in arsenic-exposed areas and 121 individuals living in non-exposed area in Bangladesh were recruited as study subjects. Arsenic content in drinking water, hair and nails were estimated by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) and LDH activity was assayed by a spectrophotometer. Significant increase in LDH activity was observed with increasing concentrations of arsenic in water, hair and nails. Further, the study subjects were split into four groups based on the three ways of each exposure metrics (water, hair and nail arsenic concentrations) where the study subjects in the non-exposed area were used as a reference (lowest exposure) group. LDH activity was found to be increased in the higher exposure groups of water and hair arsenic concentrations. LDH activity was also increased at low to medium exposure groups of nail arsenic concentrations.Thus, the elevated plasma LDH activity might be helpful for the early prognosis of organ or tissue damage in the individuals who were exposed to arsenic chronically.

Association between arsenic exposure and plasma cholinesterase activity: a population based study in Bangladesh

BACKGROUND

Arsenic is a potent pollutant that has caused an environmental catastrophe in certain parts of the world including Bangladesh where millions of people are presently at risk due to drinking water contaminated by arsenic. Chronic arsenic exposure has been scientifically shown as a cause for liver damage, cancers, neurological disorders and several other ailments. The relationship between plasma cholinesterase (PChE) activity and arsenic exposure has not yet been clearly documented. However, decreased PChE activity has been found in patients suffering liver dysfunction, heart attack, cancer metastasis and neurotoxicity. Therefore, in this study, we evaluated the PChE activity in individuals exposed to arsenic via drinking water in Bangladesh.

METHODS

A total of 141 Bangladeshi residents living in arsenic endemic areas with the mean arsenic exposure of 14.10 +/- 3.27 years were selected as study subjects and split into tertile groups based on three water arsenic concentrations: low (< 129 microg/L), medium (130-264 microg/L) and high (> 265 microg/L). Study subjects were further sub-divided into two groups ( 50 microg/L) based on the recommended upper limit of water arsenic concentration (50 microg/L) in Bangladesh. Blood samples were collected from the study subjects by venipuncture and arsenic concentrations in drinking water, hair and nail samples were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PChE activity was assayed by spectrophotometer.

RESULTS

Arsenic concentrations in hair and nails were positively correlated with the arsenic levels in drinking water. Significant decreases in PChE activity were observed with increasing concentrations of arsenic in water, hair and nails. The average levels of PChE activity in low, medium and high arsenic exposure groups were also significantly different between each group. Lower levels of PChE activity were also observed in the > 50 microg/L group compared to the

CONCLUSIONS

We found a significant inverse relationship between arsenic exposure and PChE activity in a human population in Bangladesh. This research demonstrates a novel exposure-response relationship between arsenic and PChE activity which may explain one of the biological mechanisms through which arsenic exerts its neuro-and hepatotoxicity in humans.

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MESH Headings

• Adult
• Age Factors
• Arsenic/adverse effects
• Arsenic/analysis
• Arsenic/blood
• Arsenic Poisoning/diagnosis
• Bangladesh/epidemiology
• Cholinesterases/blood
• Cholinesterases/drug effects
• Environmental Exposure/adverse effects
• Female
• Hair/chemistry
• Humans
• Male
• Nails/chemistry
• Sex Factors
• Water Pollutants, Chemical/adverse effects
• Water Pollutants, Chemical/analysis
• Water Supply/analysis

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Affiliation(s)

Nurshad Ali Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Md Ashraful Hoque Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Abedul Haque Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Kazi Abdus Salam Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Md Rezaul Karim Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Aminur Rahman Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Khairul Islam Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Zahangir Alam Saud Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh
Md Abdul Khalek Department of Statistics, Rajshahi University, Rajshahi-6205, Bangladesh
Anwarul Azim Akhand Department of Genetic Engineering and Biotechnology, Dhaka University, Dhaka-1000, Bangladesh
Mostaque Hossain Department of Medicine, Rajshahi Medical College Hospital, Rajshahi-6000, Bangladesh
Abul Mandal School of Life Sciences, University of Skövde, PO Box 408, SE-541 28 Skövde, Sweden
Md Rezaul Karim Department of Applied Nutrition and Food Technology, Islamic University, Kushtia-7003, Bangladesh
Hideki Miyataka Laboratory of Molecular Nutrition and Toxicology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan
Seiichiro Himeno Laboratory of Molecular Nutrition and Toxicology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan
Khaled Hossain Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205, Bangladesh

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Dichotomous effects of lead acetate on the expression of metallothionein in the liver and kidney of mice

Metallothionein (MT) is a low-molecular-weight cysteine-rich protein which has a high affinity for metals and plays important roles in the protection against metal toxicity. As little information is available concerning the mechanism of MT induction by lead (Pb) compounds, we investigated the induction of MT by Pb acetate both at mRNA and protein levels in mice. Administration of Pb increased the levels of MT-I mRNA in the liver and kidney in six strains of mice. However, MT protein was detected only in the liver, and little or no increases in MT protein were detected in the kidney of any strains of mice. Speciation of metals in the liver cytosol showed that the major metal bound to MT was zinc but not Pb. The increases in plasma concentrations of interleukin-6 suggest that the production of interleukin-6 by Pb administration is involved in the induction of MT in the liver. Treatment of renal cells with Pb in vitro also resulted in the increase in MT mRNA but little increase in MT protein. These data suggest that Pb exerts a dual effect on MT expression; enhancement of MT gene transcription both in the liver and kidney and suppression of MT mRNA translation in the kidney.

Possible involvement of radical intermediates in the inhibition of cysteine proteases by allenyl esters and amides

In order to investigate crystallographically the mechanism of inhibition of cysteine protease by alpha-methyl-gamma,gamma-diphenylallenecarboxylic acid ethyl ester 3, a cysteine protease inhibitor having in vivo stability, we synthesized N-(alpha-methyl-gamma,gamma-diphenylallenecarbonyl)-L-phenylalanine ethyl ester 4. Reaction of 4 with thiophenol, the SH group of which has similar pK(a) value to that of cysteine protease, produced oxygen-mediated radical adducts 6 and 7 in ambient air but did not proceed under oxygen-free conditions. Catalytic activities of two thiol enzymes including cathepsin B were also lowered in the absence of oxygen. These results suggest that cysteine protease can act through an oxygen-dependent radical mechanism.

Effect of pH on 1H-NMR Spectroscopy of Mouse Urine

1H-NMR spectroscopy of urine has been proved to be a powerful tool in metabonomic investigations in the field of chemical toxicity evaluation and disease diagnosis. However, most studies on urinary metabolite profiling by 1H-NMR have been conducted using rat urine. In the course of experiment on 1H-NMR analysis of urine samples of mice administered selenium compound, we noticed a substantial variation of chemical shift of citrate among individual mice. To clarify the effect of urinary pH on chemical shift of citrate, we compared 1H-NMR spectra of urine samples obtained from selenium-treated mice and untreated mice as well as those from untreated rats. The results clearly showed a linear relationship between urinary pH and chemical shift of citrate in 1H-NMR spectra both in mice and rats. The urine of mice exhibited a wider variation of pH, resulting in a wider variation of chemical shift of citrate than that of rats. We also recognized a clear peak of trimethylamine in urine of mice, but not that of rats. These data indicate that more attention should be paid to the characteristics of mouse urine with special reference to pH and trimethylamine metabolism in the analysis of NMR spectroscopy.

Lanostane triterpenoids and triterpene glycosides from the fruit body of Fomitopsis pinicola and their inhibitory activity against COX-1 and COX-2

Two new lanostane triterpenoids (1, 2) and 10 new lanostane triterpene glycosides (3-12) have been isolated from the fruit bodies of Fomitopsis pinicola. Their structures were established primarily by NMR experiments and chemical methods, and their biological activity against COX-1 and COX-2 was investigated.

Antiinflammatory activity of heat-treated Cassia alata leaf extract and its flavonoid glycoside

Antiinflammatory activities of heat-treated Cassia alata leaf extract and kaempferol 3-O-gentiobioside (K3G) isolated from C. alata as an abundant flavonoid glycoside were studied by comparing their activities with the activities of sun-dried C. alata leaf extract. We observed strong inhibitory effects on Concanavalin A-induced histamine release from rat peritoneal exudate cells both in the extracts of heat-treated and sun-dried C. alata leaves. Furthermore, the heat-treated leaf extract exhibited stronger inhibitory effects than the effects of the sun-dried leaf extract at low concentrations in the studies of Concanavalin A-induced histamine release, 5-lipoxygenase inhibition, and also inhibition of cyclooxygenases (COX-1 and COX-2), whereas K3G showed weak inhibitory effects on Concanavalin A-induced histamine release, 5-lipoxygenase, and COX-1. No anti-hyaluronidase effect was detected in any of the materials tested.

Synthesis and biological activities of fluorinated chalcone derivatives

We have designed and synthesized new 5-lipoxygenase inhibitors, fluorinated 3,4-dihydroxychalcones, and evaluated their biological activities with respect to antiperoxidation activity and in vitro antitumor activities. All fluorinated chalcones tested showed 5-lipoxygenase inhibition on rat basophilic leukemia-1 (RBL-1) cells and inhibitory action on Fe(3+)-ADP induced NADPH-dependent lipid peroxidation in rat liver microsomes. The potencies were comparable or better to that of the lead 3,4-dihydroxychalcone. 6-Fluoro-3,4-dihydroxy-2',4'-dimethoxy chalcone (7) was the most effective compound in the in vitro assay using a human cancer cell line panel (HCC panel) consisting of 39 systems.

Wistar strain rats as the model for IgE antibody experiments

The amount of plasma IgE antibody formed and its change over time were investigated by enzyme-linked immunosorbent assay (ELISA) in male and female Sprague-Dawley (SD), Donryu, and Wistar strain rats. IgE antibody formation was initiated by injecting a mixture of 2,4-dinitrophenylated ascaris extract (DNP-As) as antigen and killed Bordetella pertussis as adjuvant into the paws of the animals. The amount of IgE antibody formed was low on day 10 in both male and female SD (40-80 ng/ml) and Donryu (20-40 ng/ml) strain rats, and an increase in the amount was observed on day 20. The peak value of IgE antibody was observed day 10 in Wistar strain rats and was 130 and 200 ng/ml in the male and female rats, respectively. These results suggest that Wistar strain rats produce the most IgE antibody when DNP-As is used as antigen and they can serve as a model for allergic diseases.

Synthesis and physiological activity of novel tocopheryl glycosides

Vitamin E glycosides were synthesized and enzymatic hydrolysis was examined for use as potential pro-drugs, however, the glycoside bond was found to be stable. On the other hand, among the glycosides synthesized, dl-alpha-tocopherylglucoside (6b) and dl-alpha-tocopherylmannoside (6c) showed strong inhibitory action on histamine release from mast cells. In addition, 6c also showed a suppressive action on IgE antibody formation. Thus, tocopheryl glycoside showed new properties compared to tocopherol (vitamin E). In particular, 6c was shown to be a novel lead compound with excellent manifold anti-allergic activity and anti-inflammatory activity.

Antioxidative and 5-lipoxygenase inhibiting activities of novel bis(4-hydroxy-2,3,5-trimethylphenoxy)alkyl derivatives

Novel bis(4-hydroxy-2,3,5-trimethylphenoxy)alkyl derivatives were synthesized and evaluations were made of their inhibiting action on Fe3+-ADP induced lipid peroxidation in rat liver microsome and reducing action on alpha,alpha-diphenyl-beta-picrilhydrazyl (DPPH), a stable radical, in addition to their inhibiting action on 5-lipoxygenase (5-LO), an enzyme that synthesizes leukotrienes. We performed a structure-activity correlation study on these derivatives. A strong Fe3+-ADP induced lipid peroxidation preventing activity was observed for the derivatives with an odd number of methylene groups including 1,3-bis(4-hydroxy-2,3,5-trimethylphenoxy)propane (3b) and 3a. No change in the DPPH reducing activity was found with change in the number of methylene groups. 5-LO inhibiting activity among the derivatives was the highest for 1,6-bis(4-hydroxy-2,3,5-trimethylphenoxy)hexane (3e). MM2 calculations were performed to find a stable steric structure for the derivatives, and 1,5-bis(4-hydroxy-2,3,5-trimethylphenoxy)pentane (3d) showed a strong activity in both antioxidative action and 5-LO inhibiting action.

Synthesis and biological activities of novel antiallergic agents with 5-lipoxygenase inhibiting action

Novel benzimidazole derivatives were synthesized and their pharmacological activities were examined. These compounds showed a good suppressive action on histamine release from rat peritoneal mast cells produced by antigen-antibody reaction, an antagonistic action on guinea pig ileum contraction caused by histamine, an inhibitory action on 5-lipoxygenase in rat basophilic leukemia-1 (RBL-1) cells, and a preventive action on NADPH dependent lipid peroxidation induced by Fe3+-ADP in rat liver microsomes. In addition, 1-[2-[2-(4-Hydroxy-2,3,5-trimethylphenoxy)ethoxy]-ethyl]-2-(4-meth yl-1-homopiperazino)-1H-benzimidazole difumarate (BOM1006) exhibited a dose dependent suppressive action on 48 h homologous passive cutaneous anaphylaxis (PCA) reaction in rats orally administered the drug.

Post-initiation effects of a super critical extract of propolis in a rat two-stage carcinogenesis model in female F344 rats

Post-initiation modifying effects of dietary administration of a super critical extract of propolis on major organs were examined using a two-stage carcinogenesis model. Groups of 21 or 22 F344 female rats were treated sequentially with 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN, i.g.), 7,12-dimethylbenz[a]anthracene (DMBA, i.g.), 1,2-dimethylhydrazine (DMH, s.c.) and N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN, in drinking water) during the first 3 weeks for initiation, and then administered diet containing 0.1 or 0.01% propolis for 33 weeks. Further groups were treated with the carcinogens alone, 0.1% propolis alone or basal diet alone. All surviving animals were killed at week 36, and major organs were examined histopathologically for development of preneoplastic and neoplastic lesions. The incidence and multiplicity of mammary carcinomas were significantly decreased by the 0.1 and 0.01% propolis treatments. In the urinary bladder, the incidence of PN hyperplasia but not tumors was, in contrast, significantly increased by 0.1% propolis. Similarly, the number and area of glutathione S-transferase placental form (GST-P)-positive liver foci were significantly elevated with this high dose. The results indicate that a low dose of a super critical extract of propolis may find application as a potent chemopreventor of mammary carcinogenesis.

Synthesis of benzimidazole derivatives as antiallergic agents with 5-lipoxygenase inhibiting action

Syntheses were conducted of novel benzimidazole derivatives that suppress histamine release from mast cells, inhibit 5-lipoxygenase, and possess antioxidative action. Among the compounds synthesized, 1-[2-[2-(4-hydroxy- 2,3,5-trimethylphenoxy)ethoxy]ethyl]-2-(4-methyl-1- homopiperazino)benzimidazole (22) potently suppressed histamine release from rat peritoneal mast cells triggered by the antigen-antibody reaction, inhibited 5-lipoxygenase in rat basophilic leukemia-1 (RBL-1) cells, and prevented the NADPH-dependent lipid peroxidation induced by Fe(3+)-ADP in rat liver microsomes, in addition to an antagonizing the contraction of guinea pig ileum caused by histamine.

Inflammatory action of 8-methoxypsoralen-spermine photoproduct (8-MOP-Spm-P(GFC)) and effects of various drugs on rat paw edema induced by 8-MOP-Spm-P(GFC)

The photoproducts produced by irradiating 8-methoxypsoralen (8-MOP) in the presence of spermine (Spm) were fractionated using gel filtration chromatography (GFC) on a Sephadex G-25 column. As a result, two bands which were characterized by the effects on hyaluronidase activity were obtained. The first band strongly activated the hyaluronidase, but a second band did not exhibit any effect on the enzyme activity. The first and second bands contained photoproducts with molecular weights (MW)>2700 and MW<728, respectively, determined by the GFC method. The photoproducts, 8-MOP-Spm-P(GFC) obtained from the first band, but not the photoproducts with lower MW from the second band, showed enzyme activating action. 8-MOP-Spm-P(GFC) induced paw edema, which was stronger in the first phase than the second one in rats, differing from that induced by carrageenin. This photoproduct was a substance with lower cell toxicity because it did not cause hemolysis on red blood cells or the release of lactic dehydrogenase from mast cells in rats. The effects of various drugs on 8-MOP-Spm-P(GFC)-induced edema were investigated. As a result, edema formation was inhibited by drugs with an anti-histaminic action, such as alimemazine, dl-chlorpheniramine, promethazine, ketotifen and azelastine, and with anti-serotonin action such as cyproheptadine. On the other hand, tranilast did not show significant inhibition and indomethacin showed a tendency to increase its formation. These results suggested that 8-MOP-Spm-P(GFC) is a new inflammatory substance and is very useful as an agent to develop new anti-inflammatory drugs without cyclooxygenase inhibitory action.

Synthesis of trimethylhydroquinone derivatives as anti-allergic agents with anti-oxidative actions

A novel series of trimethylhydroquinone derivatives was synthesized and evaluated for their anti-lipid peroxidation activity in rat liver microsomes, inhibition of rat basophilic leukemia-1 (RBL-1) cell 5-lipoxygenase and 48 h homologous passive cutaneous anaphylaxis (PCA) activity in rats. 4-[4-[4-(Diphenylmethyl)-1-piperazinyl]-butoxy]-2,3,6-trimethyl phenol (9c) exhibited the ability to inhibit Fe(3+)-ADP induced NADPH dependent lipid peroxidation (IC50 = 5.3 x 10(-7) M), 5-lipoxygenase ((IC50 = 3.5 x 10(-7) M) and PCA reaction (57% inhibition at 100 mg/kg p.o.).

A study of novel antiallergic agents with eosinophilic infiltration inhibiting action

The antiallergic action of a series of novel mono-O-substituted trimethylhydroquinones was investigated. Among this series of the compounds, 4-[4-[4-(diphenylmethyl)-1-piperazinyl]butoxy]-2,3,6- trimethylphenol (compound 3) showed a potent antihistaminic action (pA2 = 7.11) and an antiasthmatic action (100 mg/kg. p.o) on sensitized guinea pigs. Moreover, this compound exhibited a strong eosinophilic infiltration inhibiting action on sensitized mice (100 mg/kg p.o.).

Evaluation of propolis (II): effects of Brazilian and Chinese propolis on histamine release from rat peritoneal mast cells induced by compound 48/80 and concanavalin A

To establish a biological method for evaluating propolis and to reveal their anti-allergic action, the effects of the ethanol and water extracts (EA-ET and WA-WT, respectively) from Brazilian, Chinese and Japanese propolis on the histamine release induced by compound 48/80 and concanavalin A (Con A) were investigated. The relation between the inhibitory activities of these extracts on the histamine release and their E(1 cm)1% values were also examined. As a result, the following was found: 1) 0.003-0.01% ethanol and 0.03-0.1% water extracts inhibited the histamine release induced by compound 48/80 and Con A, and the inhibitory potencies of the former extracts were more than 10 times stronger than those of the latter extracts, making it clear that both the ethanol and water extracts possess an anti-allergic action; 2) most of the ethanol and water extracts responded to the histamine release induced by both the histamine releasers in a concentration-dependent manner; 3) the inhibitory activities of 0.003% EM from Hebei Province, EP from Sichuan Province, EQ from Zhejiang Province and ER from Anhui Province in China were weaker than those of 0.01% corresponding extracts, whereas 0.001% ED-EH from Brazilian propolis, EM, EN from Henan Province in China and EP-ER promoted the Con A-induced histamine release of more than 10%, suggesting that such extracts must be carefully given to humans; 4) the inhibitory potencies of only 0.03-0.1% water extracts from Chinese propolis on the Con A-induced histamine release related excellently with their E(1 cm)1% values; 5) from the results of the relation between the inhibitory potencies of the propolis extracts and their E(1 cm)1% values, it was suggested that an unknown compound, being a poorly water-soluble compound which is a non-flavonoid, with an anti-allergic action is contained in propolis; 6) to precisely evaluate the anti-allergic action of the propolis, the biological method, which measures the inhibitory activities of the propolis extracts on histamine release, was markedly superior to the physicochemical method.

Evaluation of propolis. I. Evaluation of Brazilian and Chinese propolis by enzymatic and physico-chemical methods

To establish a method of evaluating propolis, the effects of the ethanol and water extracts from various collecting of propolis from different countries and plant sources on hyaluronidase activity were investigated along with their absorption spectra and specific absorbance (E(1%)1 cm value). The relations between the hyaluronidase inhibitory activities of these extracts and their E(1%)1 cm values were also examined, and the following was found: 1) the enzyme inhibitory activities of the ethanol extracts were more potent than those of the water extracts; 2) the enzyme inhibitory activities of the ethanol extracts from Araucaria angustifolia (BERT.) O. KTZE were low compared with those of other ethanol extracts; 3) the enzyme inhibitory activities of all the ethanol extracts correlated excellently with their E(1%)1 cm values, but in the water extracts, they decreased with increase in E(1%)1 cm values; 4) the water extracts of Chinese propolis from Hebei, Jiangsu, Sichuan and Zhejiang Provinces inhibited weakly compared with that from Brazilian and other Chinese propolis; 5) the shapes of absorption bands of the propolis extracts and the E(1%)1 cm values were approximately dependent on the place or the plant source from which propolis was collected. These experimental results indicated that, for the exact evaluation of propolis, the enzymatic method, measuring the hyaluronidase inhibitory activity, was superior to the physicochemical method.

Pharmaceutical properties of freeze-dried formulations of egg albumin, several drugs and olive oil

The freeze-dried ternary formulations of meclizine (MZ, an anti-motion sickness drug), prednisolone (PRED, an anti-inflammatory drug) and norfloxacin (NFLX, an anti-microbial drug) which are poorly water-soluble and are low bioavailability drugs, were prepared using egg albumin and olive oil. The powder X-ray diffractions, the dissolution rate and the bioavailabilities in vivo of these formulations were studied in comparison with each drug alone. By forming ternary formulations of these drugs, the dissolution rates of the drugs from the formulations were significantly improved compared with each drug alone. The results of their powder X-ray diffraction measurements showed that these drugs in the ternary formulations presented in an amorphous form, indicating increased dissolution rates. On the other hand, the plasma concentrations of these drugs increased significantly after oral administration in formulations to rats, except for the NFLX formulation, and the areas under the concentration-time curves (AUC) of the ternary formulations of MZ, PRED and NFLX were 2.1, 1.6 and 1.3 times those of the drugs alone, respectively. From these results, it was proven that formulations consisting of egg albumin, olive oil and poorly water-soluble drugs were useful preparations for improving the drug's disadvantageous pharmaceutical properties.

Synthesis and anti lipid-peroxidation activity of hydroquinone monoalkyl ethers

A series of hydroquinone monoalkyl ethers was synthesized and evaluated for anti lipid-peroxidation activity in rat liver microsomes. 4-Hexyloxy-2,3,6-trimethylphenol (9), having a low redox potential, as well as ascorbic acid exhibited the strongest anti lipid-peroxidation activity (IC50 = 4.2 x 10(-7) M). Structure-activity relationship studies demonstrated that the inhibitory effect of hydroquinone monoalkyl ethers on lipid peroxidation was increased by the acquisition of an optimum hydrophobicity and decreased by an insufficient or excessive hydrophobicity.

Syntheses and inhibitory effects on gastric lesions of 4-guanidinomethylbenzoic acid arylamides

A novel series of 4-guanidinomethylbenzoic acid (GMBA) arylamides was synthesized. Several showed more potent inhibitory effects on stress-induced gastric lesion in rats than cetraxate. We selected 4-guanidinomethylbenzoic acid (2'-ethoxycarbonyl)phenylamide 3 for further pharmacological assessments because it had low toxicity. Compound 3 showed significant inhibitory effects on stress-, HCl-ethanol- and indomethacin-induced gastric lesions and gastric secretion, the ED50 values being 34.4, 45.0 and 23.0 mg/kg (p.o.) and 240 mg/kg (i.d.), respectively. Furthermore, this compound restored the reduction of gastric mucus caused by the stress-loading and inhibited compound 48/80-induced ulcer.

Pharmacological and pharmaceutical properties of freeze-dried formulations of egg albumin, indomethacin, olive oil, or fatty acids

Formulations consisting of egg albumin, indomethacin (IND), and olive oil or fatty acids, were prepared by vigorous stirring using a high-speed homogenizer and subsequent freeze-drying. To confirm the anti-inflammatory properties and ulcerogenic effects of the formulations, we examined the action of the formulations on carrageenan-induced edema in rats as well as their ulcerogenic actions in the same species. Compared with IND alone, albumin-IND-olive oil (9:1:4.3), albumin-IND-linolenic acid (9:1:4.3), albumin-IND-linolic acid (9:1:4.3), albumin-IND-oleic acid (9:1:4.3), albumin-IND-stearic acid (9:1:4.3), and albumin-IND-tristearin (9:1:4.3) formulations all exhibited a more potent inhibitory effect on carrageenan-induced edema. In addition, the inhibitory effects on edema formation of an albumin-IND (9:1) complex was as strong as that of IND alone. These results suggested that the bioavailability of IND was increased by olive oil, fatty acid, and tristearin as absorbefacient agents. The increase in the bioavailability was evident from the fact that the mean plasma levels, maximum plasma levels (Cmax), and area under plasma concentration-time curve (AUC) values after oral administration of the albumin-IND-olive oil (9:1:4.3) formulation was significantly greater than that after administration of the drug alone. With respect to their ulcerogenic properties, the formulations were significantly less active than IND alone, suggesting that a reduction in the ulcerogenic activity of IND was by produced complexation with egg albumin.

Pharmacological and pharmaceutical properties of freeze-dried formulations of egg albumin, indomethacin, olive oil, or fatty acids. II

To confirm the increased bioavailability of indomethacin (IND) when incorporated in a preparation with egg albumin and olive oil, we studied the detailed pharmaceutical characteristics of a ternary formulation consisting of egg albumin, IND and olive oil. From the results of X-ray powder diffraction measurements, the drug in the formulation was found to be in an amorphous form. When orally administered to rats, the ternary formulation significantly increased the plasma concentration and cumulative biliary and urinary excretion of IND alone as well as the urinary excretion of its major metabolite, desmethylindomethacin, compared with the drug alone. In addition, the dissolution rate of IND from the formulation was higher than that of the drug alone. These results clearly suggest that the bioavailability of IND was markedly improved by incorporating it in a protein-drug formulation containing olive oil as an absorbefacient element, and this effect may be due to an increased absorption of IND.

Inflammatory activity of polymeric photoproducts of chlorpromazine

To confirm the inflammatory activity of polymeric photoproducts (CPZ-polymers) of chlorpromazine (CPZ), which were obtained by gel filtration of a UV-pre-irradiated CPZ aqueous solution, the histamine release from rat peritoneal exudate cells was studied and the paw-inflammation in mice induced by these CPZ-polymers was examined. CPZ-polymers induced a dose-dependent histamine release at concentrations of 1, 3 and 10 mg/ml. This effect was approximately one-tenth of that of compound 48/80. Furthermore, CPZ-polymers markedly induced lasting paw-edema in a dose-dependent manner, the swellings remaining for at least 96 h. When intraperitoneally injected into mice, CPZ-polymers induced a significant elevation of histamine release in the peritoneal cavity 0.5 h after the injection, compared with a control group. The histamine levels in the cavities returned to normal within the next 0.5 h, and remained normal for at least 23 h, indicating that histamine release may be caused only in the early stages of CPZ-polymer-induced inflammation. The inflammatory activity of the CPZ-polymers suggests that they are inflammatory substances formed from CPZ by UV-irradiation.

Syntheses and inhibitory effects on gastric lesions of trans-guanidinomethylcyclohexane carboxylic acid arylamides

A novel series of trans-guanidinomethylcyclohexanecarboxylic acid (trans-GMCHA) arylamides was synthesized. The several trans-GMCHA arylamide derivatives showed more potent inhibitory effects on the stress- and HCl-ethanol-induced gastric ulcers than cetraxate in rats. In acute toxicity studies in mice, most amides showed such severe toxicity that all mice injected with these compounds (50 mg/kg, i.p.) died. However, mice injected with the trans-GMCHA (2'-,3'- and 4'-ethoxycarboxy)phenylamide (7, 8 and 9) which bear an alkyloxycarbonyl group at benzene ring survived. From these results, trans-GMCHA (2'-ethoxycarbonyl)phenylamide (7) was selected as a promising anti-ulcer agent.

Activation of hyaluronidase by 8-methoxypsoralen-polyamine photoproducts

Ultraviolet radiation of 8-methoxypsoralen (8-MOP) in the presence of various polyamines resulted in stable photoproducts that were very soluble in water and showed hyaluronidase-activating properties. Among them, the photoproducts obtained from the reaction systems of 8-MOP-spermine and 8-MOP-spermidine markedly activated hyaluronidase. The enzyme activity was not affected by 8-MOP alone and the photoproduct of 8-MOP (8-MOP-P). From these facts, it was suggested that the photoproducts with hyaluronidase-activating properties might play an important role in the onset of 8-MOP-induced photosensitivity.

3-O-alkylascorbic acids as free-radical quenchers: synthesis and inhibitory effect on lipid peroxidation

A novel series of 3-O-alkylascorbic acids (3-RASA, 3a-n) was synthesized to act as radical scavengers for active oxygen species and free radicals, and their redox potentials and inhibitory effects on lipid peroxidation in rat liver microsomes were evaluated. The redox potentials of the 3-RASA compounds were increased by the substituent group to 90-190 mV above the potential for ascorbic acid (i.e., 3-RASA compounds were harder to oxidize). Although 3-O-dodecylascorbic acid (3c) and 3-O-(decylcarbomethyl)ascorbic acid (3i) differed in their redox potentials, they both markedly inhibited lipid peroxidation in rat liver microsomes to a similar extent (IC50 = 3.1 and 3.3 X 10(-6) M, respectively). Structure-activity relationship studies demonstrated that the anti lipid peroxidation activity of the 3-RASA compounds was markedly dependent upon their hydrophobicity.

Photoactivation mechanism of hyaluronidase by chlorpromazine

A pre-irradiated chlorpromazine (CPZ) in pH 7.2 and aqueous solutions activated hyaluronidase, and it showed the enzyme-activating action even after 7 days of irradiation. This indicates that the stable photoproducts of CPZ activated the enzyme. But promazine and CPZ-5-sulfoxide, which are photoproducts of CPZ, did not activate the enzyme in the presence and absence of UVA. The dimer and higher molecular weight (MW) products of CPZ that were obtained by treating the pre-irradiated CPZ solution with gel permeation chromatography showed the hyaluronidase by activating action without UVA. In addition, photoactivation of hyaluronidase by CPZ was inhibited by radical quenchers. This suggested that the photoproducts with enzyme-activating action were produced via some radicals. On the basis of these findings, a possible mechanism for photoactivation of hyaluronidase by CPZ was proposed.