Evaluation of the Impacts of Marine Salts and Asian Dust on the Forested Yakushima Island Ecosystem, a World Natural Heritage Site in Japan.

To elucidate the influence of airborne materials on the ecosystem of Japan's Yakushima Island, we determined the elemental compositions and Sr and Nd isotope ratios in streamwater, soils, vegetation, and rocks. Streamwater had high Na and Cl contents, low Ca and HCO(3) contents, and Na/Cl and Mg/Cl ratios close to those of seawater, but it had low pH (5.4 to 7.1), a higher Ca/Cl ratio than seawater, and distinct (87)Sr/(86)Sr ratios that depended on the bedrock type. The proportions of rain-derived cations in streamwater, estimated by assuming that Cl was derived from sea salt aerosols, averaged 81 % for Na, 83 % for Mg, 36 % for K, 32 % for Ca, and 33 % for Sr. The Sr value was comparable to the 28 % estimated by comparing Sr isotope ratios between rain and granite bedrock. The soils are depleted in Ca, Na, P, and Sr compared with the parent materials. At Yotsuse in the northwestern side, plants and the soil pool have (87)Sr/(86)Sr ratios similar to that of rainwater with a high sea salt component. In contrast, the Sr and Nd isotope ratios of soil minerals in the A and B horizons approach those of silicate minerals in northern China's loess soils. The soil Ca and P depletion results largely from chemical weathering of plagioclase and of small amounts of apatite and calcite in granitic rocks. This suggests that Yakushima's ecosystem is affected by large amounts of acidic precipitation with a high sea salt component, which leaches Ca and its proxy (Sr) from bedrock into streams, and by Asian dust-derived apatite, which is an important source of P in base cation-depleted soils.

Two cases of congenital cholesteatoma of the tympanic membrane.

Congenital cholesteatoma of the tympanic membrane is rare, and lesions without a history of otitis media or any other adverse events involving the tympanic membrane are extremely rare. We report two cases of this lesion; one was a 3-year-old girl who underwent removal of a cholesteatoma using retroauricular approach and a partial myringoplasty with an underlay technique, and the other was a 2-year-old girl in whom a cholesteatoma was enucleated without grafting. This disease is thought to be of embryonic origin.

Sources of dissolved mine drainage and atmospheric transported lead: a comparative case study in Japan and Sweden.

A comparative case study in Naganobori Japan and Falun Sweden of runoff water from copper mines shows that the water and its particulates, filtered with a cutoff of 0.45 microm, have different lead isotope ratios pointing to different origins for the lead. While the larger particles have a lead ratio indicative of the atmospheric anthropogenic pollution the soluble lead has that of the copper ores. The domestic atmospheric lead ratio in Japan is homogeneous and characteristic of emissions from the incineration of waste. Lead pollution transported from the Asian continent by westerly winds can be distinguished from the Japanese pollution by its more thorogenic lead ratios, in for example analyses of copper moss from Naganobori.

Analysis of feasibility and toxicity of concurrent chemoradiotherapy with S-1 for locally advanced squamous cell carcinoma of the head and neck in elderly cases and/or cases with comorbidity.

PURPOSE: The aim of this study was to evaluate the feasibility and toxicity of concurrent chemoradiotherapy (CCRT) with S-1 in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN) in elderly cases and/or cases with comorbidity. METHODS: Fifty eligible patients with stage III (15 cases) or stage IV (35 cases) SCCHN were treated with CCRT. Thirteen cases had an advanced age of over 75 years and 37 cases had comorbidity. Definitive radiotherapy was delivered up to a total dose of 66-70.2 Gy. The patients received two courses of oral S-1 (40 or 50 mg twice a day [80 or 100 mg/day]) for 2 weeks followed by 1 week of rest while receiving CCRT. RESULTS: All the patients received the planned radiotherapy and at least one course of S-1. Grade 3 mucositis occurred in 20% of the patients (10/50). Grade 3 neutropenia occurred in 12% (6/50) and leukocytopenia occurred in 6% (3/50) of the cases. Pathologically, the complete response rates were 93% in stage III and 54% in stage IV. CONCLUSION: Concurrent chemoradiotherapy with S-1 is a safe, well-tolerated and effective regimen for locally advanced SCCHN in elderly cases and/or cases with comorbidity.

The efficacy and safety of concurrent chemoradiotherapy for maxillary sinus squamous cell carcinoma patients.

OBJECTIVE: Combined treatment modality, e.g., definitive surgery followed by radiotherapy (RT) and definitive RT with concurrent chemotherapy, has been applied for advanced maxillary sinus squamous cell carcinoma (MSSCC) patients to obtain a better survival with organ preservation in Japan. METHODS: The outcome of 40 patients with MSSCC between 1991 and 2007 in our institute was analyzed retrospectively. There were 36 males and 4 females, the average age being 59.5 years (ranging from 34 to 81 years). The median follow-up time was 66.1 months. All the patients had received a combined treatment consisting of definitive surgery, RT, and intra-arterial or systemic chemotherapy. The chemotherapeutic regimen was different depending on the performance status and/or complications of the patients. Since 1998, concurrent chemoradiotherapy with cisplatin, 5-fluorouracil, methotrexate and leucovorin regimen (CCRT-PFML) instead of neo-adjuvant chemotherapy has been applied. RESULTS: The overall 5-year survival rate was 59.2%, the 5-year disease-specific survival rate was 71.7%, and the 5-year organ preservation survival rate was 42.4%. In the group receiving CCRT-PFML, the overall 5-year survival rate was 60.0%, the 5-year disease-specific survival rate was 76.0%, and the 5-year organ preservation survival rate was 60.3%. CONCLUSION: CCRT-PFML for advanced MSSCC patients is feasible to preserve the organs without reducing the survival rate.

Concurrent chemoradiotherapy for T4 patients with hypopharyngeal and laryngeal squamous cell carcinomas.

OBJECTIVES: Concurrent chemoradiotherapy (CCR) was given for the previously untreated T4 hypopharyngeal and laryngeal squamous cell carcinoma patients and the response and survival rates were evaluated. PATIENTS AND METHODS: A total of 23 patients, namely, 15 for hypopharynx and 8 for larynx were eligible. These patients were given cisplatin and 5-fluorouracil based chemotherapeutic regimens with conventional radiotherapy for a total dose of 66.6-70.2 Gy. RESULTS: Ten out of the 15 hypopharyngeal carcinoma patients and 4 out of the 8 laryngeal carcinoma patients showed a complete response at the primary sites. The 5-year disease-specific survival rate was 59.4% in all the patients, 51.9% in the hypopharyngeal carcinoma patients, and 71.0% in the laryngeal patients. Seven out of the 12 resectable hypopharyngeal carcinoma patients and 4 out of 8 laryngeal carcinoma patients were able to do without total laryngectomy. CONCLUSIONS: Based on these results, the survival rate in the hypopharyngeal and laryngeal T4 carcinoma patients treated by CCR seems to be satisfactory and the possibility of organ preservation for the advanced patients is indicated.

Decrease of creatinine clearance rate with aging in patients with head and neck cancer in Japan.

BACKGROUND: We aimed to clarify the reason for the lower dosage of cis-platinum (CDDP) in patients with head and neck cancer in Japan compared with that in other countries, by evaluating renal function. METHODS: We studied 375 patients with head and neck cancer who had been hospitalized from January 1998 to October 2005, to evaluate and treat the disease. The creatinine clearance rate (Ccr) was calculated at least three times before beginning the treatments, and the average Ccr was estimated to evaluate the renal function. RESULTS: The Ccr decreased with aging, and the percentages of patients with Ccr lower than 65 ml/min per 1.73 m(2) were 27.1% of patients in their fifties, 36.8% in their sixties, 62.3% in their seventies, and 87.5% in their eighties. There was no correlation between renal function and the Japanese lifestyle (i.e., diet. water consumption). CONCLUSION: The renal function of Japanese decreases rapidly with aging, whereas that of Americans is maintained for longer periods. The poor renal function of Japanese is one of the causes of the need to reduce the dosage of or avoid the administration of CDDP in cancer patients.

Evolutionary control of leaf element composition in plants.

Leaf nitrogen (N) and phosphorus (P) concentrations are correlated in plants. Higher-level phylogenetic effects can influence leaf N and P. By contrast, little is known about the phylogenetic variation in the leaf accumulation of most other elements in plant tissues, including elements with quantitatively lesser roles in metabolism than N, and elements that are nonessential for plant growth. Here the leaf composition of 42 elements is reported from a statistically unstructured data set comprising over 2000 leaf samples, representing 670 species and 138 families of terrestrial plants. Over 25% of the total variation in leaf element composition could be assigned to the family level and above for 21 of these elements. The remaining variation corresponded to differences between species within families, to differences between sites which were likely to be caused by soil and climatic factors, and to variation caused by sampling techniques. While the majority of variation in leaf mineral composition is undoubtedly associated with nonevolutionary factors, identifying higher-level phylogenetic variation in leaf elemental composition increases our understanding of terrestrial nutrient cycles and the transfer of toxic elements from soils to living organisms. Identifying mechanisms by which different plant families control their leaf elemental concentration remains a challenge.

Alternative normalization method of atmospheric polycyclic aromatic hydrocarbons pollution level recorded by tree bark.

An alternative normalization method was developed for evaluating atmospheric polycyclic aromatic hydrocarbons (PAHs) pollution level when using tree bark as a passive sampling medium. Perylene (PER), which mainly stems from natural biogenic processes, was proposed as a "natural internal compound" (NIC) of atmospheric PAHs accumulation processes from air into the bark, and a concentration ratio of target PAH to PER (RPAH/PER) was used to minimize the uncertainty in the evaluation of atmospheric PAHs pollution level. Systematic investigation of the effects of intrinsic bark characteristics and extrinsic seasonal meteorological conditions on the partition processes of atmospheric PAHs indicated that RPAH/PER is as an alternative index as compared to bark mass concentration (BMCPAH, ng/g dry bark), lipid mass concentration (LMCPAH, ng/g lipid of bark), and area mass concentration (AMCPAH, ng/m2 surface area of bark) for the evaluation of atmospheric PAHs pollution and that it allows more flexible sampling of tree barks. Clearly, the methodology should be expected to be useful for the objective evaluation of atmospheric pollution levels of other persistent organic pollutants when using tree bark and other passive sampling media if corresponding NICs are found in the future.

Expression of SPARC in tongue carcinoma of stage II is associated with poor prognosis: an immunohistochemical study of 86 cases.

SPARC (secretory protein acidic and rich in cysteine), also known as osteonectin or BM-40, associates with progression in various kinds of tumors. We have examined whether SPARC expression can be a prognostic marker for patients with head and neck squamous cell carcinomas (HN-SCC). We examined immunolocalization of SPARC in 86 clinical specimens of tongue carcinoma. Although there was no correlation between SPARC positivity in the tumor cells and tumor stages, the 5-year overall survival rate was significantly lower in the SPARC positive cases (28.6%) than in the SPARC negative cases (91.7%), confined to stage II patients (p < 0.001, Wilcoxon test). Additionally, in stage II cases (n = 3), frequency of the postoperative metastasis was significantly higher in SPARC positive cases (5/8, 62.5%) than in the negative cases (1/15, 6.7%) (p < 0.01, chi2 test). Together with these results, SPARC can be a beneficial prognostic marker for the stage II tongue carcinoma, of which clinical outcomes are sometimes difficult to predict.

Seasonal and long-term change in lead deposition in central Japan: evidence for atmospheric transport from continental Asia.

Long-range transport of air pollution from continental Asia is currently an important issue concerning the Japanese environment, especially in regions susceptible to acidification due to low buffering capacity, such as Murakami, Niigata prefecture, located on the west coast of central Japan. Evidence for long-range transport was obtained through lead and lead isotopic analysis of 84 archived precipitation filters, showing seasonal changes in lead deposition from May 1999 to May 2002. Lead deposition was highest in winter and spring (November through May) each year and lowest in summer. Computed 72-h back trajectories showed that in winter air masses were predominantly transported from the northwest, passing over northern China and eastern Russia, whilst in summer air masses predominantly originated from the southeast passing over Japan. Lead isotopic analysis showed higher (208)Pb/(206)Pb during winter, indicating that lead originated from a different source. A plot of (207)Pb/(206)Pb vs. (208)Pb/(206)Pb identified a thorogenic component, which is excess (208)Pb compared to a standard lead growth curve, indicative of certain lead ores and coals in continental Asia. The data provided evidence of long-range transport of lead from continental Asia to Japan. Bark pockets included within the trunks of two Japanese cedar trees harvested near Murakami, dating between 1972 and 1982, exhibited lead isotope ratios indicative of Japanese-sourced lead. In contrast, current (2003) bark showed thorogenic ratios, consistent with a relative decline in Japanese-sourced and increase in continental-sourced lead.

Chronological trends in trace metals recorded by a tree bark pocket in Yakushima Island, Japan.

Bark included within the trunk of a 200-year-old Japanese cedar tree harvested in Yakushima Island, Japan, a World Natural Heritage Site located 150 km south of mainland Japan and 800 km east of Shanghai, China, was analysed for trace metals by ICP-MS providing a chronology of atmospheric pollution. The concentration of V, As and Pb in decadal sections of the bark pocket increased 30 to 50 fold from 1900-09 to 1960-69, indicating increased atmospheric deposition of these metals. The trend coincided with the establishment and expansion of heavy industries in Kyushu, Japan, resulting in locally high levels of air pollution. V, As and Pb subsequently declined, reflecting lower industrial emissions following air pollution control legislation from the late 1960's and decline in heavy industries. Ni, Cu and Zn showed a relatively small, 7 to 10 fold increase over time. Lead isotope ratios in the bark pockets shifted from about 0.84 to 0.86 for 207Pb/206Pb and from 2.04 to 2.10 for 208Pb/206Pb, showing that the origin of atmospheric lead changed over time from coal to more diverse sources.

Antitumor and antiangiogenic effects of interleukin 12 gene therapy in murine head and neck carcinoma model.

Interleukin-12 (IL-12) plays a critical role in producing an immune response, as indicated in many ways, e.g., induction of interferon-gamma (IFN-gamma), and augmentation of the cytotoxic activity of resting activated T cells and natural killer (NK) cells. In this study, we examined whether intratumoral injection of a recombinant retrovirus vector expressing IL-12s induce antitumor and antiangiogenic effects in a murine model using a murine head and neck squamous cell carcinoma (NR-S1). In vitro the levels of vascular endothelial growth factor (VEGF) mRNA and protein expression were decreased in IL-12 gene transfected NR-S1 cell. in vivo direct IL-12 gene therapy resulted in significantly remarkable inhibition of tumor growth compared to the control group. The tumor regression by direct IL-12 gene therapy was also associated with decreased vessel density, and apoptosis and increased infiltration of CD8(+) T cells and CD56(+) NK cells in the tumor increased. Also, the number of IFN-gamma expressed cells of spleen cells was increased in the treatment group compared with the control group. These results suggested that direct IL-12 gene therapy appears to be effective in reducing tumor growth by triggering both antiangiogenic effects and an immunological enhancing mechanism through induction of IFN-gamma.

The relationship of the human glutathione S-transferase P1 polymorphism and chemotherapeutic sensitivity in head and neck squamous carcinoma.

GSTP1, which encodes GSTPi, has a polymorphic site at codon 105 (exon 5), where an adenosine-to-guanine (A-G) transition causes an isoleucine-to-valine substitution (I105V). Recent studies have found that subjects with the valine allele display a significantly lower enzyme activity and less effective capability of detoxification. We hypothesized that head and neck squamous cell carcinoma (HNSCC) might respond differently to chemotherapeutic agents, especially cisplatin (CDDP) because of the presence of GSTP1 I105V polymorphism. Seventeen types of HNSCC cell lines were investigated with the MTT method, western blot, RT-PCR and direct sequence to examine the relationship between the sensitivity to CDDP and expression of GSTPi. There was a significant degree of difference in cell death among each cell line in the sensitivity test with CDDP, however, we did not find differences in the band density of the protein and mRNA expression levels of GSTPi. In the direct sequence examination we detected 4 subjects heterozygous of polymorphism GSTP1. The frequency was 23.5% in the 17 cell lines examined, and all 4 subjects showed a good response to CDDP treatment. A heterozygous polymorphism might alter the function of the GSTPi due to significantly lower enzyme activity and less effective capability of detoxification. Two other subjects which showed a good response to CDDP treatment did not show any polymorphism. These results indicated that there is another locus that reduces GSTPi activity, and that the mechanisms of CDDP resistance was multifactorial. Further study is required to conclude whether the GSTP1 I105V polymorphism might be useful as a predictive marker for multi-drug resistance.

A comparison of lead isotope ratios in the bark pockets and annual rings of two beech trees collected in Derbyshire and South Yorkshire, UK.

ICP-MS analysis of the bark pockets and annual rings of two beech (Fagus sylvatica L.) trees collected from Longshaw, Derbyshire and Swinton, South Yorkshire in the UK recorded differences in the (206)Pb/(207)Pb isotope ratio. In the Longshaw sample, the (206)Pb/(207)Pb isotope ratio of the bark pockets ( approximately 1914-1998, 78-260 microg g(-1) Pb) declined from approximately 1.16 to 1.12, whilst the annual rings (1899-1998, 0.2-2.5 microg g(-1) Pb) had a (206)Pb/(207)Pb ratio of approximately 1.18. In the Swinton sample, the bark pockets (approximately 1919-1998, 7-78 microg g(-1) Pb) declined from 1.15 to 1.11 and the annual rings (1899-1998, 0.2-0.5 microg g(-1) Pb) from 1.18 to 1.15. The data implied that the bark pockets accumulated lead directly from the atmosphere through wet and dry deposition, whilst the annual rings accumulated lead from the soil via the roots. The bark pockets recorded a relative decline in the accumulation of lead from indigenous sources, such as lead smelting and coal combustion (1.17-1.19), and increase in imported sources such as the smelting of Australian ores (1.04) and leaded petrol usage (1.06-1.09). In contrast, the annual rings at Longshaw recorded ratios typical of indigenous lead, whilst the annual rings in Swinton recorded a relatively small decrease in (206)Pb/(207)Pb reflecting leaded petrol usage. The decline in (206)Pb/(207)Pb of the bark pockets was consistent with the historical decline in (206)Pb/(207)Pb of atmospheric lead recorded in peat, lake sediments and archival herbage at other UK locations.

Anti-tumor effect of vitamin A and D on head and neck squamous cell carcinoma.

OBJECTIVES: Vitamin A and D(3) have a very strong differentiation induction effect. STUDY DESIGN: We examined the anti tumor effect on head and neck squamous cell carcinoma (HNSCC) by treatment with several vitamins having strong differentiation induction effects in vitro. METHODS: We used KB cell that an oral floor squamous cell carcinoma, vitamins as all-trans retinoic acid (ATRA), 4-[3,5-bis (trimethylsilyl) benzamido] benzoic acid (TAC-101), 1alpha,25(OH)(2)D(3) (calcitriol) and 22-oxa-1,25-(OH)(2)D(3) (OCT). We determined receptors of vitamin A and D(3) using RT-PCR. Furthermore, we investigated the proliferation of tumor cells in concentration dependency using [3H]TdR uptake method, apoptosis and apoptosis related factors using TUNEL method and real-time PCR, cell cycle changes using flow cytometry, changing of the sensitivity of using MTT method, cytokine production and the angiogenesis factor using ELISA, by treatment with these vitamins. RESULTS: The deficit of RAR-beta was found in the KB cell. Each vitamin suppressed the cell proliferation, induced apoptosis, and cell cycle arrest, upregulated sensitivity of the chemotherapeutics drugs and downregulated several angiogenesis factors and an apoptotic factor; survivin. CONCLUSIONS: These results support the idea that vitamin A, D(3) and their derivatives are useful for preventing and/or treating patients with HNSCC.

Seasonal change in the level and the chemical forms of aluminum in soil solution under a Japanese cedar forest.

The level of dissolved aluminum and its chemical forms in soil solutions consecutively collected by a porous cup vacuum sampler were monitored over a period from January 2001 to December 2001 at a Japanese cedar (Cryptomeria japonica) forestry area susceptible to acid deposition to characterize current soil dynamics and to evaluate potential tree damages. Distinction and characterization of Al species with differential toxicities were performed by two complementary speciation techniques; cation-exchange HPLC with fluorometric detection using 8-hydroxyquinoline-5-sulfonic acid (HQS) and size-fractionation/inductively coupled plasma atomic emission spectrometry (ICP-AES). The concentrations of free Al (mainly Al3+ and Al(OH)2+) and inert Al (existing as the complexed and/or colloidal forms) ranged between 0-150 microM and 10-50 microM, respectively. The concentrations of inert Al were mostly below 40 microM during an annual cycle and showed no marked seasonal variation, while free Al concentrations showed a clear tendency to increase in the spring and summer seasons (in the period from April to August) probably due to the enhanced activity of microbial nitrification and the resultant soil acidification. Major cations and anions were also regularly determined and their seasonal changes were correlated with that of the dissolved Al concentration. Correlations between total Al (mainly existing as free Al) and the related species (and environmental conditions) were as follows: Al and Mg (R=0.96, P<0.01), Al and Ca (R=0.97, P<0.01), Al and NO3- (R=0.68, P<0.01), Al and temperature (R=0.68, P<0.01), Al and solution pH (R=-0.61, P<0.01), solution pH and NO3- (R=-0.65, P<0.01).

Effects of combined therapy with interleukin 2 and interleukin 12 gene-transfected tumor vaccine for head and neck carcinoma.

BACKGROUND: The biological effects of cytokines are coming to be understood. The therapeutic effects of interleukin (IL) 2, IL-12, and interferon gamma (IFN-gamma) in cancer treatment have been reported, but there are problems when these cytokines are systemically used as therapeutic agents. OBJECTIVE: To examine the efficacy of IL-2 and IL-12 gene-transfected tumor cell vaccines for head and neck squamous cell carcinoma (SCC). METHODS: Homozygous mice with the autosomal recessive nude gene (BALB/c nu/nu mice) were inoculated subcutaneously in the right flank with cells from a human oral floor SCC cell line (KB cells). The mice were then injected with IL-2 and IL-12 gene-transfected KB cells (KB/IL-2 and KB/IL-12 cells, respectively) irradiated with 2000 rad (20 Gy). RESULTS: No mice died soon after the injection of the gene immunotherapy. The treatment with either KB/human IL-2 (hIL-2) or KB/murine IL-12 (mIL-12) was not very effective. However, the treatment with both KB/hIL-2 and KB/mIL-12 cells significantly and safely inhibited the growth of established tumors (P =.04). There was no significant difference in antitumor effect between once-weekly and twice weekly injections of both KB/hIL-2 and KB/mIL-12 cells. CONCLUSION: Double gene immunotherapy is safe and effective treatment for SCC in mice.

Environmental monitoring of historical change in arsenic deposition with tree bark pockets.

ICP-MS analysis recorded historical change (c. 1846 to 2002) in the arsenic concentration of bark included within the trunks (tree bark pockets) of two Japanese oak trees (Quercus crispula), collected at an elevated location approximately 10 km from the Ashio copper mine and smelter, Japan. The arsenic concentration of the bark pockets was 0.016 +/- 0.003 microg cm(-2) c. 1846 (n = 5) and rose 50-fold from c. 1875 to c. 1925, from approximately 0.01 to 0.5 microg cm(-2). The rise coincided with increased copper production in Ashio from local sulfide ores, from 46 tons per year in 1877 to 16,500 tons per year in 1929. Following a decline in arsenic concentration and copper production, in particular during the Second World War, a second peak was observed c. 1970, corresponding to high levels of production from both local (6,000 tons per year) and imported (30,000 tons per year) ores, smelted from 1954. Compared to the local ores, the contribution of arsenic from imported ores appeared relatively low. Arsenic concentrations declined from c. 1970 to the present following the closure of the mine in 1974 and smelter in 1989, recording 0.058 +/- 0.040 microg cm(-2) arsenic (n = 5) in surface bark collected in 2002. The coincident trends in arsenic concentration and copper production indicated that the bark pockets provided an effective record of historical change in atmospheric arsenic deposition.

Evaluation of the historical records of lead pollution in the annual growth rings and bark pockets of a 250-year-old Quercus crispula in Nikko, Japan.

The annual growth rings and bark pockets of a 250-year-old Japanese oak (Quercus crispula), collected from the Nikko National Park, Japan in 2000 AD, were analysed by ICP mass spectrometry. The annual rings, sampled in 5-year increments, recorded Pb concentrations from 0.01 to 0.1 mg kg(-1) and there was no significant change in concentration with time. In contrast, bark pocket samples dating from 1875 to the present showed a progressive increase in Pb concentration with time, from approximately 0.1 to 10 mg kg(-1). Shoots of epiphytic moss growing on the tree trunk contained 17 mg kg(-1) Pb. The bark pockets recorded historical increases in airborne Pb pollution accompanying the industrialisation of Japan, which was initiated by the opening of Japan's borders from 1854. This increase was not reflected by the annual rings. The 206Pb/207Pb isotope ratio of the bark pockets decreased from approximately 1.18 to 1.16 from 1964 to the present, indicating changes in the sources of Pb pollution. The 206Pb/207Pb isotope ratio of the moss shoots was similar to the current bark (1.16). The data showed bark pockets to be more effective than annual rings for recording historical change in airborne lead pollution.