Association between lignan polyphenol bioavailability and enterotypes of isoflavone metabolism: A cross-sectional analysis

Lignan polyphenols derived from plants are metabolized by bacteria in the gut to mammalian lignans, such as enterolactone (ENL) and enterodiol (END). Mammalian lignan intake has been reported to be associated with obesity and low blood glucose levels. However, the factors that are responsible for individual differences in the metabolic capacity for ENL and END are not well understood. In the present study, the effects of enterotypes of isoflavone metabolism, equol producers (EQP) and O-desmethylangolensin producers (O-DMAP), on lignan metabolism were examined. EQP was defined by urinary daidzein (DAI) and equol concentrations as log(equol/DAI) ≥ -1.42. O-DMAP was defined by urinary DAI and O-DMA concentrations as O-DMA/DAI > 0.018. Isoflavone and lignan concentrations in urine samples from 440 Japanese women were measured by gas chromatography-mass spectrometry. Metabolic enterotypes were determined from the urinary equol and O-DMA concentrations. Urinary END and ENL concentrations were compared in four groups, combinations of EQP (+/-) and O-DMAP (+/-). The urinary lignan concentration was significantly higher in the O-DMAP/EQP group (ENL: P<0.001, END: P<0.001), and this association remained significant after adjusting for several background variables (END: β = 0.138, P = 0.00607 for EQP and β = 0.147, P = 0.00328 for O-DMAP; ENL: β = 0.312, P<0.001 for EQP and β = 0.210, P<0.001 for O-DMAP). The ENL/END ratio was also highest in the O-DMAP/EQP group, indicating that equol and O-DMA metabolizing gut bacteria may be involved in lignan metabolism. In conclusion, urinary lignan concentrations were significantly higher in groups containing either EQP or O-DMAP than in the non-EQP/non-O-DMAP group. The variables and participants in this study were limited, which the possibility of confounding by other variables cannot be ruled out. However, there are no established determinants of lignan metabolism to date. Further research is needed to determine what factors should be considered, and to examine in different settings to confirm the external validity.

Temporal trends in bisphenol exposures and associated health risk among Japanese women living in the Kyoto area from 1993 to 2016

BACKGROUND

Bisphenols, and especially bisphenol A, are widely used as components of epoxy resins and polycarbonate. Widespread detection and potential health risks have led to bisphenol A being replaced by other alternatives, including structurally similar bisphenol analogs. Several bisphenol analogs are suspected to have similar adverse health consequences. This study examined the temporal trends in bisphenol exposure among a group of Japanese women from 1993 to 2016, and assessed the associated health risks.

METHODS

We used archived single spot urine samples of healthy Japanese women living in the Kyoto area (n = 133) collected in 1993, 2000, 2003, 2009, 2011, and 2016. We measured the concentrations of 10 bisphenols in these samples.

RESULTS

A sharp increase in the detection rates of bisphenol F was observed after 2000. There was a distinct downward trend in urinary bisphenol A concentrations and an upward trend in bisphenol E concentrations after 2009. While the hazard index for all measured bisphenols was below 1 in all subjects, bisphenol F was determined as the most important risk driver after 2000, rather than bisphenol A.

DISCUSSION

Trends of decreasing bisphenol A and increasing bisphenol E exposure especially after 2011, along with no significant change in the sum of all bisphenol analogs in urine, provide clear evidence that bisphenol A has been replaced by other bisphenols in the study population. We found no significant change in the total exposure to bisphenols during the study period. Bisphenol F might become the most important bisphenol in terms of risk, while cumulative risks due to all bisphenol exposure were deemed insignificant. Considering the accumulating evidence indicating adverse effects at lower exposure levels, further studies are warranted to assess exposure and risk from bisphenol A analogs.

Plasma eicosapentaenoic acid, a biomarker of fish consumption, is associated with perfluoroalkyl carboxylic acid exposure in residents of Kyoto, Japan: a cross-sectional study

BACKGROUND

Per- and polyfluoroalkyl substances (PFASs) are highly fluorinated organic compounds that have been widely used in industry during the past few decades. The main exposure routes for PFASs are thought to be the diet, drinking water, and dust. In this study, we aimed to evaluate the relationship between perfluoroalkyl carboxylic acids (PFCAs, members of the PFAS family) and the plasma eicosapentaenoic acid-to-arachidonic acid ratio (EPA/AA), a biological indicator of seafood intake, to determine whether seafood intake may represent a means of exposure to PFASs in the Japanese population.

METHODS

We performed a cross-sectional study using 131 plasma samples collected from residents of Kyoto, Japan in 2013 and held in the Kyoto University biological sample bank. The concentrations of perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), EPA, and AA were quantified by gas chromatography-mass spectrometry, and multiple linear regression was used to analyze the results.

RESULTS

In multiple linear regression analyses with age and eGFR, PFOA showed a significant positive linear association with age (p = 0.0005); PFHpA showed a significant negative linear association with estimated glomerular filtration rate (eGFR; p = 0.0338); and PFHpA, PFOA, PFNA, PFUnDA, and PFDoDA exhibited significant positive linear associations with EPA/AA (p = 0.0358, 0.0056, 0.0242, <0.0001, and <0.0001, respectively). Because only PFHpA and PFOA were associated with smoking, their concentrations were examined again with smoking variable included and neither showed an association with smoking habit. PFOA showed a significant linear association with EPA/AA ratio (p = 0.0072), but PFHpA did not (p = 0.051).

CONCLUSIONS

The plasma concentrations of PFOA, PFNA, PFUnDA and PFDoDA significantly associated with the EPA/AA ratio in residents of Kyoto.

Chlorinated persistent organic pollutants in human breast milk in the Miyagi Prefecture disaster-affected area 1 year after the Great East Japan Earthquake of 2011

BACKGROUND

In the Great East Japan Earthquake of 11 March 2011, an earthquake and accompanying tsunami struck the Tohoku region of northeastern Japan. Buildings collapsed and the tsunami spread waste, including hazardous materials. This study aimed to determine the concentrations of persistent organic pollutants (POPs) in the breast milk of mothers living in the disaster-affected area of Sendai 1 year after the earthquake. Temporal trends in the POPs concentrations were evaluated by comparison with previous studies.

METHODS

One hundred breast milk samples were obtained from lactating mothers at a hospital in Sendai in 2012. The results were compared with those from other years to examine whether there were changes in the POPs concentrations after the earthquake. We measured polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as chlordanes, using gas chromatography-mass spectrometer (GC-MS) with negative chemical ionization, and dichlorodiphenyl trichloroethane (DDT) and its metabolites using GC-MS with electron impact ionization.

RESULTS

The mean total PCBs (11 congeners), total chlordane, and total DDT concentrations were 76.2 ng/g lipid, 39.8 ng/g lipid, and 73.5 ng/g lipid, respectively. For the samples collected in 2012, the concentrations of POPs in breast milk showed minimal changes compared with results from previous years for samples collected at the same hospital in Sendai.

CONCLUSIONS

Our study demonstrates that 1 year after the earthquake and tsunami, the concentrations of chlorinated POPs in breast milk had not changed substantially.

Association between urinary zinc excretion and isoflavone-metabolizing enterotypes among Japanese females: a cross-sectional study

BACKGROUND

Zinc absorption and competition among gut bacteria have been reported in animal studies. Thus, gut bacteria may modify zinc availability in humans. Metabolism of intestinal bacteria is known to be necessary for the activation of several phytoconstituents in the body. For example, equol, a typical substance of soybean isoflavone, is produced by intestinal bacteria metabolizing daidzein and the enterotype is one of distinct ones among Japanese population. The difference in the intestinal microflora can modify the bioavailability of zinc. In this study, we examined urinary zinc concentrations in adult female equol producers (EQPs).

METHODS

Urine samples from women participating in health examinations in Miyagi, Okinawa, Kyoto, Kochi, and Hokkaido prefectures were used; from total 17,484 samples, approximately 25 samples were randomly selected for each age group from 30 to 60 years per region (subsample: n = 520), and 520 samples with available urinary zinc concentration (determined by flame atomic absorption analysis) and enterobacterial type were analyzed. EQP was defined as log(equol/daidzein) ≥ -1.42, and urinary concentrations were corrected for creatinine concentration. Urinary zinc concentrations were compared by Student's t-test and multiple regression analyses.

RESULTS

The geometric mean urinary zinc concentration (µg/g-Cr) was lower in EQP than in non-EQP (p = 0.0136 by t-test after logarithm transformation). On the other hand, there was no correlation between urinary zinc concentration with daidzein (r = -0.0495, P = 0.436) and equol concentrations (r = -0.0721, P = 0.256). There was a significant negative association between urinary zinc concentration and EQP (β = -0.392, P = 0.0311) after adjusting with other potential confounding variables, such as daidzein intake.

CONCLUSIONS

The results suggest that gut bacteria that produce equol are involved in the metabolism of zinc. Based on previous studies, the bacteria that affect the metabolism of both substances are thought to be Enterococcus. Future studies are expected to identify specific intestinal bacteria for zinc availability and understand individual differences in the effects of micronutrients.

Diabetes Mellitus May Exacerbate Liver Injury in Patients with COVID-19: A Single-Center, Observational, Retrospective Study

INTRODUCTION

The spread of coronavirus disease 2019 (COVID-19) is having a profound effect on global health. In this study, we investigated early predictors of severe prognosis from the perspective of liver injury and risk factors for severe liver injury in patients with COVID-19.

METHODS

We examined prognostic markers and risk factors for severe liver injury by analyzing clinical data measured throughout the course of the illness and the disease severity of 273 patients hospitalized for COVID-19. We assessed liver injury on the basis of aminotransferase concentrations and fibrosis-4 (FIB-4) index on admission, peak aminotransferase concentration during hospitalization, aminotransferase peak-to-average ratio, and albumin and total bilirubin concentrations. Furthermore, we analyzed age, aspartate aminotransferase (AST) concentrations, FIB-4 index on admission, hypertension, diabetes mellitus (DM), dyslipidemia, cerebral infarction, myocardial infarction, and body mass index as mortality risk factors.

RESULTS

We identified advanced age as a risk factor. Among biochemical variables, AST concentration and FIB-4 index on admission were associated with high mortality. AST on admission and peak AST during hospitalization were significantly higher in the non-surviving (n = 45) than the discharged group (n = 228). Multivariable Cox hazards analyses for mortality showed significant hazard ratios for age, peak AST, and FIB-4 index on admission (p = 0.0001 and 0.0108, respectively), but not in a model including AST and FIB-4 index on admission. Furthermore, the AST peak was significantly higher among non-surviving patients with DM than in those without DM.

CONCLUSIONS

We found that advanced age, high AST, and FIB-4 index on admission and a higher peak AST during hospitalization are risk factors for poor COVID-19 prognosis. Furthermore, DM was a risk factor for exacerbation of liver injury among non-surviving patients. The AST concentration and FIB-4 index should be assessed periodically throughout hospitalization, especially in patients with high AST values on admission and those with DM.

Exposure to phthalate esters in Japanese females in Kyoto, Japan from 1993 to 2016: Temporal trends and associated health risks

Phthalates are used as plasticizers in many products used in daily life worldwide. Due to industrial and economic developments, exposure among general population to phthalates may vary geographically and temporally. However, studies are lacking for investigating temporal changes in phthalate exposure in the Japanese population. In the present study, the temporal trends in exposure to various phthalates were assessed among a group of Japanese adult female population over 1993-2016 and derived associated risks. For this purpose, urine samples of healthy Japanese females in Kyoto, Japan (N = 132) collected in 1993, 2000, 2003, 2009, 2011, and 2016, were employed and measured for the concentrations of 18 phthalate metabolites. Over this period, the detection rates of mono(3-carboxypropyl) phthalate (MCPP) and monoisobutyl phthalate (MiBP) decreased, and the geometric means of the urinary concentrations of mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) showed a significant decreasing trend. Cumulative risk due to exposure to dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), butyl benzyl phthalate (BBP), and di-2-ethylhexyl phthalate (DEHP) showed a dramatic decrease only between 1993 and 2000. The maximum hazard quotient (HQ_M) was attributed to DEHP in most subjects regardless of sampling year. This study showed the temporal trend of the exposure of Japanese females to several phthalate esters over two decades. As of the late 2010's, DEHP was still the predominant component of phthalate ester exposure in the population. The HI value, however, indicates that direct risk due to phthalate exposure was unlikely among the studied population.

Urinary equol levels are positively associated with urinary estradiol excretion in women

Isoflavones found in soy products are a promising class of nutrients that may have a positive effect on human health. In particular, the phytoestrogen metabolite equol is associated with a reduced risk of developing female hormone-related diseases. However, the effect of equol on estrogen remains unclear. Equol can modify blood and urinary estradiol (E2) levels. The aim of this cross-sectional study was to examine the associations between urinary estrogen levels, equol levels, and equol production status in Japanese women. We analyzed urine samples from 520 women by gas chromatography-mass spectrometry. Urinary E2 and 4-hydroxylated E2 levels were higher in equol producers (EQP) than in non-EQPs (P < 0.0001 and P=0.00112, respectively). After adjusting for age and tobacco use by analysis of covariance, the association remained significant (β = 0.299, P < 0.0001). Analysis of covariance demonstrated that equol levels in urine were also positively associated with urinary E2 (β = 0.597, P < 0.0001). The log equol concentration showed a significant, but moderate, negative association with the serum E2 concentration (β = − 0.0225, P = 0.0462). Our findings suggest that equol may promote urinary E2 excretion and modify blood E2 levels in women.

Systematic Review Protocol for the Current State of Chemical Exposure in Infants via Breast Milk, Artificial Milk and Dairy Products

Many studies have shown that human breast milk is contaminated with various chemicals. In the proposed systematic review, the aim is to identify and summarize the available literature regarding chemical exposure via breastfeeding or the feeding of artificial formula. MEDLINE (PubMed) will be the primary source in this literature search. Primary studies that analyzed one or more chemicals of interest in breast milk or artificial milk and that reported information on concentrations will be eligible for this review. Conference abstracts will not be included in the review unless access to the data is easy. First, the titles and abstracts of identified articles will be screened by two or more researchers. Then, a full-text review will be conducted to extract data from the included articles and code them for classification. The results of the search and classification will be summarized narratively and bibliometrically. The aim of the review is to analyze trends in publications according to year and region from the viewpoint of target chemicals, location, range of concentrations, and health outcomes.

Letter to the editor regarding "spatiotemporal association of low birth weight with Cs-137 deposition at the prefecture level in Japan after the Fukushima nuclear power plant accidents"

In the previous report, association between increased low birth weight prevalence and radiocesium deposition after 2011 Fukushima nuclear disaster was found. However, the statistical analyses therein raised several questions. First, ecological variables are not justified enough to adjust potential confounding. Second, the spatiotemporal regression model does not consider temporal reduction in radiation dose rate. Third, dose-response plot between dose rates and odds ratios overestimates R² and underestimates p value.

Serological Tests for SARS-CoV-2 Coronavirus by Commercially Available Point-of-Care and Laboratory Diagnostics in Pre-COVID-19 Samples in Japan

The number of COVID-19 patients in Japan is considered low, compared with U.S. and European countries. However, recent serological survey reported that several percent of population showed IgG positive to SARS-CoV-2. Specificity in the assays might influence the estimate, and possibility of overdiagnosis should be investigated. Serological tests for SARS-CoV-2 coronavirus were performed in pre-COVID-19 sera in Japan (400 healthy subjects in 2012-2015). Lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) showed 1.5% (6/400) and 1.75% (7/400) IgG positives, respectively. Among those false positive samples, only one sample was positive in both LFA and ELISA (0.25%; 95% CI: 0.006-1.39%). Possible bias from pooling method was examined by Monte Carlo method and the possibility was unlikely at low false positive rate. Previous surveys might overestimate COVID-19 seroprevalence in several populations of Japan. These false positives could be excluded by combination of different diagnostics. Nonetheless, the result of seroprevalence should be carefully interpreted in less prevalent areas.

Association of social support with gratitude and sense of coherence in Japanese young women: a cross-sectional study

PURPOSE

Recent studies have shown that perceived social support is associated with gratitude and sense of coherence, but evidence for this concept remains scarce. In the present study, we investigated relationships between social support, gratitude, and sense of coherence, focusing on the construct of and source of social support among young women.

METHODS

The study was conducted in 2014 in Japan. Participants comprised 208 female university students (aged 19.9 ± 1.1 years), who completed a self-administered anonymous questionnaire regarding perceived social support, gratitude, and sense of coherence.

RESULTS

Emotional and instrumental social support from acquaintances were found to be lower than those from family and friends. Gratitude was positively correlated with all forms of social support except instrumental social support from acquaintances. However, sense of coherence was positively correlated with both emotional and instrumental social support from family and only emotional social support from acquaintances. Multiple regression analysis showed that emotional support from family and emotional support from acquaintances were positively associated with gratitude whereas emotional support from family was associated with sense of coherence.

CONCLUSION

These results indicate that emotional social support from family was related to both gratitude and sense of coherence.

Characteristics of radon and thoron exhalation rates in Okinawa, subtropical region of Japan

Radon and thoron exhalation rates from the ground surface were estimated in three islands of Okinawa Prefecture, a subtropical region of Japan. In situ measurements of the exhalation rates were conducted at a total of 88 points using an accumulation technique with a ZnS(Ag) scintillation detector. The radon and thoron exhalation rates were calculated to be 1-137 (arithmetic mean: 21) mBq m(-2) s(-1) and 32-6244 (1801) mBq m(-2) s(-1), respectively. In the surface soil samples collected at 53 measurement points, (238)U and (232)Th series concentrations were estimated to be 17.9-254.0 (64.0) Bq kg(-1) dry and 17.8-136.1 (58.8) Bq kg(-1) dry, respectively. The maximum rates and concentrations were observed in the dark red soil area. Recent studies strongly suggest that the base material of the soils may be the eolian dust derived from the southeastern part of China, a high background radiation area. The eolian dust is, therefore, considered to be an enhancer for the radon and thoron exhalations in Okinawa.

Effects of sustained stimulation with multi-wall carbon nanotubes on immune and inflammatory responses in mice

Possible effects of multi-wall carbon nanotubes (MWCNTs) on immune and inflammatory responses were examined in mice. Female ICR mice were given a single intraperitoneal administration (2 mg/kg body weight) of either MWCNTs, carbon black (CB), or crocidolite (blue asbestos) and controls received a vehicle of 2% sodium carboxymethyl cellulose (CMC Na). In the peritoneal cavity of MWCNT-administered mice, the liver had changed to a rounded shape and fibrous adhesions were seen on internal organs. Peritoneal cells overexpressed mRNA for genes of T helper (Th)2 cytokines (interleukin [IL]-4, IL-5, and IL-13), Th17 cytokine (IL-17), pro-inflammatory cytokines/chemokines (IL-1β, IL-33, tumor necrosis factor α, and monocyte chemotactic protein-1), and myeloid differentiation factor 88 for at least 2 weeks after the administration of MWCNTs, while those of Th1 cytokine genes (IL-2 and interferon γ) were overexpressed several weeks later and expression levels remained high up to 20 weeks. In MWCNT-treated mice, the numbers of leukocytes, monocytes, and granulocytes in the peripheral blood and the expression of the leukocyte adhesion molecules, cluster of differentiation (CD)49d and CD54, on granulocytes were increased 1 week after administration and remained high up to week 20. Production of ovalbumin-specific IgM and IgG(1) was enhanced by MWCNTs. These changes were not observed after CB or crocidolite administration. Thus, this study showed that MWCNTs exhibited sustained stimulating effects on immune and inflammatory responses, unlike the other mineral fibers with structural similarities.

Teratogenicity of multi-wall carbon nanotube (MWCNT) in ICR mice

A possible teratogenicity of multi-wall carbon nanotube (MWCNT) was assessed using ICR mice. MWCNTs were suspended in 2% carboxymethyl cellulose and given intraperitoneally or intra-tracheally to pregnant ICR mice on day 9 of the gestation. All fetuses were removed from the uterus on day 18 of the gestation, and were examined for external and skeletal anomalies. In the intraperitoneal study, various types of malformation were observed in all MWCNT-treated groups (2, 3, 4 and 5 mg/kg body weight, intraperitoneal). In contrast, such malformations were observed in groups given 4 or 5 mg/kg body weight, but not in that treated with 3 mg/kg in the intratracheal study. In either study, the number of litters having fetuses with external malformation and that of litters having fetuses with skeletal malformations were both increased in proportion to the doses of MWCNT. The present results are the first to report that MWCNT possesses the teratogenicity at least under the present experimental conditions. Mechanism(s) to result such malformations is yet unclear and further experiment is necessary.

Flame retardant tetrabromobisphenol A induced hepatic changes in ICR male mice

Tetrabromobisphenol A (TBBPA) is widely used throughout the world as flame retardant for electronic equipment or building materials, and is detected in air at the dismantling plant, sewage sludge, sediment or human serum samples. In the present study, we examined the effects of TBBPA on the liver when administered to mice for 14 consecutive days. Groups of 7 (control group) or 8 (treated group) Crlj:CD1 (ICR) male mice were given 0 (control), 350, 700 or 1400mg/kg body weight/day TBBPA (99.1% pure) in olive oil for 14 days. The serum concentration of total-cholesterol in high-dose (1400mg/kg BW) group was higher than those of the control group. Absolute and relative liver weights were dose-dependently increased, and were significantly increased in high-dose (1400mg/kg BW) group. The histological findings showed that the slight enlargement of the hepatocytes, inflammatory cell infiltrations and focal necrosis of hepatocytes were more marked in liver of treated groups (from 350mg/kg BW) than in control group. The present data suggest the possibility of inducing hepatic lesion by TBBPA dosing.

Effects of tetrabromobisphenol A, brominated flame retardant, in ICR mice after prenatal and postnatal exposure

Tetrabromobisphenol A (TBBPA), brominated flame retardant, is produced in the largest amounts globally for use in plastics or building materials. TBBPA has been detected in sediment, air at the dismantling plant or human serum samples. In the present study, we examined the effects of prenatal and postnatal exposure to TBBPA in mice. TBBPA (99.1% pure) in diet was administered to pregnant ICR mice at doses of 0% (control), 0.01%, 0.1% or 1.0% from gestational day 0 to weaning at postnatal day 27. The average daily food intake and body weight of dams showed no significant differences between the control and treated groups. There were no dose-related effects on reproductive data. Serum concentrations of total-cholesterol and liver weights of treated dams and offspring were higher than those of the control mice. Histological findings in treated dams or offspring showed the increase of focal necrosis of hepatocytes and inflammatory cell infiltration in the liver, and increase of dilation or atrophy of renal tubules and cyst in the kidney. TBBPA was developed as a new, safe class of flame retardant and was not highly toxic. However, the present data suggested that TBBPA caused a lipid metabolic disorder and hepatic or kidney lesion, under these conditions.

Chlorpropham-induced splenotoxicity and its recovery in rats

To determine the reversibility of hematological and pathological changes in spleen induced by sub-chronic administration of chlorpropham (CIPC), male F344 rats were given CIPC in the diet at 0, 600, 3000 or 15,000 ppm for 13 weeks (administration period) and then were given standard (0 ppm) diet for 10 weeks (recovery period). At 0, 1, 2, 4 or 10 weeks in the recovery period, 5 rats in each groups were examined for hematology and pathology. At the end of CIPC administration, dose-dependent and significant methemoglobinemia, anemia, splenomegaly and pathological lesions indicating hemolytic anemia were observed in all the treated groups. The hematological changes, congestion of red pulp, lymphoid atrophy, increased extramedullary hematopoiesis in spleen and hematopoietic cell hyperplasia in bone marrow were diminished during the 10 weeks recovery period. However, increased hemosiderin deposition and capsular fibrosis in spleen of the treated groups remained at the end of recovery period. The results indicated that hematological changes induced by sub-chronic administration of CIPC were reversible but hemosiderin deposition and fibrosis in spleen were not reversible in the recovery period examined, suggesting the significance of splenic lesion in CIPC-toxicity.

Chronic toxicity of thiabendazole (TBZ) in CD-1 mice

Male and female CD-1 mice (50 mice per group) were administered thiabendazole (TBZ) in diet at levels of 0 (control), 0.031, 0.125 and 0.5% for 78 weeks. A life time study was terminated after 78 weeks due to enhanced strain specific mortality. There were no significant differences in mortality between the control and treated groups. Mean body weights of high-dose groups showed significant decreases compared with the controls. The bladder weights of male and female mice of the 0.5% group were significantly higher than those of the control mice. Gross findings in treated mice included the renal atrophy, hydronephrosis, calculi in renal pelvis and/or bladder and ovarian atrophy. Microscopic findings in the kidneys of treated mice included the nephrosis, hydronephrosis or hyperplasia of transitional epithelium of renal pelvis or papilla. In the bladder of treated mice, hyperplasia or squamous metaplasia of transitional epithelium and one transitional cell papilloma were observed. Dose-dependent decreases in the incidence of spontaneous lesion in the male or female reproductive system were recognized. It is concluded that TBZ is not carcinogenic to CD-1 mice of both sexes. However, caution should be exercised in the long-term application of high TBZ doses.

Thiabendazole induces urinary tract toxicity in male ICR mice

Male ICR mice were administered thiabendazole (TBZ) in the diet at concentration of 0 (control), 0.8, 1.2 and 1.6% for 44 weeks. The mortality was 10, 6, 40 or 90% in control, 0.8, 1.2 or 1.6% TBZ group, respectively. In dead mice, the gross findings included the abnormalities of kidney such as atrophy, hydronephrosis or swelling in 2, 67, 95 or 96% of the 0, 0.8, 1.2 or 1.6% TBZ group, respectively. In surviving mice at the end of study, the right kidney weight of treated groups was significantly lower than that of control group. The urinary bladder weight of treated groups was significantly higher than that of control group. Gross findings in treated mice included the renal atrophy, hydronephrosis, calculi in renal pelvis or urinary bladder and thickening of the bladder wall. Microscopic findings in the kidneys of treated mice included nephrosis, hydronephrosis and hyperplasia of transitional epithelium of renal pelvis and/or papilla. In the urinary bladder, hyperplasia or squamous metaplasia of transitional epithelium were found in treated mice. Administration of TBZ in the diet for 44 weeks results in nephrosis and calculus formation in the renal pelvis and urinary bladder of male ICR mice, and is associated with hyperplasia of transitional epithelium of renal pelvis or urinary bladder.

Effects of chlorpropham (CIPC) on the hemopoietic system of rats

Male F344 rats were given 0 or 3% chlorpropham in the diet and at 2, 4, 6, 8 or 13 weeks of administration, five rats in each group were examined for hematology, plasma clinical chemistry and pathology. Marked splenomegaly and hepatomegaly were observed in treated rats at 2-13 weeks of administration. Red blood cell counts, hemoglobin concentration, packed cell volume and platelet counts were significantly decreased and methemoglobin level, mean corpuscular volume and white blood cell counts were significantly increased in treated rats at 2-13 weeks of administration. The covalent binding of m-chloraniline m-CA, (the hydrolytic metabolite of chlorpropham) was observed in hemoglobin or splenic protein of treated rats, but only small amounts of free m-CA were present in blood or spleen. Congestion, hemosiderin deposits, extramedullary hemopoiesis and lymphoid atrophy in spleen and hyperplasia of hemopoietic cells in bone marrow were observed in treated rats at 2-13 weeks and fibrosis in splenic capsule were observed in treated rats at 4-13 weeks. The pathological changes in spleen rather than hematological changes progressed during administration, suggesting splenotoxicity of CIPC in rats.

Subchronic toxicity of chlorpropham (CIPC) in ICR mice

Male and female ICR mice were given 0, 1875, 7500 or 30,000 ppm of chlorpropham (CIPC) in the diet for 13 weeks. Methemoglobin levels of male and female mice in the 7500 and 30,000 ppm groups were significantly elevated. Hemoglobin concentration, packed cell volume, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and white blood cell count of male and female mice in the 30,000 ppm group were significantly increased. Dose-dependent splenomegaly was observed in male and female mice in the 7500 and 30,000 ppm group. Congestion, increased hemosiderin deposition and increased extramedullary hematopoiesis in the spleen, hematopoietic cell hyperplasia and hemosiderin deposition in bone marrow was observed dose dependently in male and female mice in the 7500 or 30,000 ppm group. Eosinophilic granular cytoplasm of hepatocytes, sinusoidal dilatation, hemosiderin deposition, extramedullary hematopoiesis and necrosis of hepatocytes were observed in the liver of male and female mice in the 30,000 ppm group. Hemosiderin deposition was increased in the kidney of male and female mice in the 30,000 ppm group. Administration of CIPC in diet for 13 weeks caused methemoglobinemia and splenomegaly in ICR mice.

[Forecast of total pollen counts of sugi (Cryptomeria japonica) from the amount of male flower development and the revised total pollen counts]

We have successfully forecast the total pollen counts of sugi (Cryptomeria japonica) since 1996 by the amount of male flower development. The amount of male flower development was observed at 11 forests in the Tanba Mountains and 10 forests in the Chugoku Mountains depending on both in Hyogo Prefecture. The amount of male flower development on each tree was assigned to one of five classes by the number of male flowers per spring. After a large harvest of male flowers, the production of male flowers declined in the following years, especially at high altitudes. It was also followed by a decrease in the number of airborne pollen grains in the later pollen season. According to an analysis of weather conditions, total pollen counts were correlated with the high temperature between July 6 and 20 and the total pollen counts of the previous season. However, the amount of male flower development was the most significant indicator for forecasting total pollen counts. Decrease in total pollen counts due to abnormal weather during the pollen season was correlated with discrepancies in forest flowering time according to observations made in the Rokko Mountains. Increase in total pollen counts was connected by a development of the sugi forest areas. Twenty percent of mature sugi forests from 1992 which showed an annual increase were associated with an increase in total pollen counts. The accuracy of the forecast was improved by revising the total pollen counts for weather conditions during the dispersion stage, a decrease in the production of male flowers at high altitude, and an increase in the production of male flowers connected by a developing forest areas.

Suppressive effects of Hochu-ekki-to, a traditional Chinese medicine, on IgE production and histamine release in mice immunized with ovalbumin

We examined the effects of Bu-Zhong-Yi-Qi-Tang (Japanese name: Hochu-ekki-to, HET), a traditional Chinese medicine, on IgE production and histamine release in mice immunized intraperitoneally with a mixture of ovalbumin (OA) and aluminum hydroxide (alum adjuvant). Three groups of mice were orally administered 0, 1.7 or 17 mg of HET on day 13 after the first immunization with a mixture of 1 microg OA and 1 mg alum adjuvant. They were again immunized with the same dose of OA plus alum adjuvant on day 14. The immunological changes in mice treated with OA alone or OA plus HET were examined, and the following findings were obtained. In the HET-treated mice, the elevation of anti-OA IgE in serum, and histamine release from basophils in blood, were significantly suppressed. A significant suppression of interleukin-4 (IL-4) secretion and proliferation of splenic lymphocytes in primary culture was also observed. A tendency to suppress the elevation of anti-OA IgG1 in serum and interleukin-2 (IL-2) secretion from splenic lymphocytes was observed in the HET-treated mice. These findings suggest that oral administration of HET suppresses IgE antibody production and histamine release in type I allergic reaction in mice immunized with OA plus alum adjuvant; this shows the efficacy of HET in treating type I allergic diseases, such as asthma.

[The increase and decrease of the total pollen counts of Sugi (Cryptomeria japonica) due to abnormal weather during pollen scattering season]

We investigated the changing total number of airborne pollen grains of Sugi (Cryptomeria japonica) due to abnormal weather during pollen scattering season. The pollen season was divided into 7 periods by the discrepancies in forest flowering time for observations. The observation forests were located at an altitude of 150 m, 220 m, 350 m, and 500 m, and 800 m in the Rokko mountains. These were located at equal spaces, when altitude was taken in the logarithm. The distribution percentage of pollen counts from 1993 to 1998 showed an almost normal distribution level. This was demonstrated by the Log-Normal Probability paper, with a middle level altitude of a 350 m forest. We could estimate the relative rate of 5 different altitude forests against the corresponding amount of pollen as shown under, 0.09 at 150 m forest, 0.34 at 220 m forest, 0.31 at 350 m forest, 0.16 at 500 m forest, 0.10 at 800 m forest. The percentage of pollen counts at the 500 m forest in 1994 and at the 350 m forest in 1995 were decreased from 95% confidence interval. We regarded the decrease in the percentage of pollen counts during these two time, as a cause weak wind velocity and wrong wind direction in Tanba mountains. It was shown that the method for dividing pollen season in different observation forests in which altitude differs, will be useful for pollen forecasts and the pollen source countermeasure.

Effects of thiabendazole (TBZ) on mitochondrial function in renal cortex of ICR mice

The effects of thiabendazole (TBZ) on mitochondrial function of the renal cortex were investigated in ICR mice. Mice were given 1000 or 2000 mg TBZ/kg body weight by gavage and mitochondria were isolated from the renal cortex for the measurement of respiratory rates. The state 3 and DNP-uncoupled respiratory rates of renal cortical mitochondria were dose-dependently depressed at 6 hours after dosing. The depression of these respiratory rates of renal cortical mitochondria was more marked at 16 hours after dosing. There was no depression in these respiratory rates of renal cortical mitochondria at 3 hours after dosing, although renal cortical concentrations of TBZ were higher than those at 6 or 16 hours after dosing. Histochemical examination revealed that NAD-linked isocitrate dehydrogenase, a marker enzyme of mitochondria, was inhibited in renal cortical tubules at 16 hours after dosing of 1000 or 2000 mg TBZ/kg body weight. Furthermore, renal cortical ATP level was significantly decreased at 16 hours after dosing of 1000 or 2000 mg TBZ/kg body weight. The results indicate that administration of TBZ caused mitochondrial dysfunction in renal cortical tubules of mice.