[A study of thyroid hormone levels of inhabitants of the cadmium-polluted Kakehashi River basin]

We compared thyroid hormone levels of inhabitants (19 men and 16 women) of the cadmium (Cd)-polluted Kakehashi River basin in Ishikawa Prefecture, with those of subjects (23 men and 47 women) living in a non-polluted area. In addition, we investigated the relationships between the thyroid hormone levels and indices of renal dysfunction induced by Cd exposure. The following results were obtained: 1) The free T4 level of females was significantly lower than that of controls. 2) The T3 level of inhabitants of both sexes was significantly higher than that of controls. 3) The level of free T4 among females became lower with the increases of urinary beta 2-microglobulin (beta 2-MG), urinary protein, urinary sugar, urinary amino acids and serum creatinine (Cr) levels, and with decreases of creatinine-clearance (CCr) and %TRP. 4) We could not find any relationship between the increase of T3 and the indices of renal dysfunction induced by Cd exposure in either sex.

Cadmium induces interleukin-8 production in human peripheral blood mononuclear cells with the concomitant generation of superoxide radicals

Acute or chronic exposure to cadmium (Cd) causes severe organ damages with the infiltration of leukocytes, neutrophils in particular occurring in the acute phase. Interleukin-8 (IL-8), a novel neutrophil chemotactic and activating cytokine, is produced by various types of cells in response to a wide variety of inflammatory stimuli. The administration of an antibody against IL-8 has been shown to inhibit neutrophil infiltration in several animal models, indicating a causal relationship between IL-8 and neutrophil infiltration. Hence, in this study we investigated whether Cd induced IL-8 production in human peripheral blood mononuclear cells (PBMC). Cd, over a wide range of concentrations, did induce human PBMC to produce large amounts of bioactive IL-8, the maximal induction being observed at 10(-4) M. The production was inhibited specifically by a metal chelating agent, ethylenediaminetetraacetic acid (EDTA). Steady level of IL-8 mRNA increased within 30 min after the addition of Cd and reached a maximal level at 2 h, decreasing thereafter. A protein synthesis inhibitor, cycloheximide, failed to inhibit IL-8 mRNA accumulation, indicating that new protein synthesis was not required for IL-8 mRNA induction. Concomitantly with the induction of IL-8, within 10 min Cd generated reactive oxygen intermediates (ROI) in human PBMC. A radical scavenger, N-acetyl-L-cysteine (NAC), inhibited both IL-8 production and the generation of ROI, implying the possible involvement of ROI in IL-8 production. This notion was also supported by our findings that a superoxide generating agent, paraquat, induced IL-8 production in human PBMC and that NAC blocked this paraquat-induced IL-8 production.

[Abnormalities of calcium, phosphorous and vitamin D metabolism with proximal renal tubular dysfunction in subjects environmentally exposed to cadmium]

Calcium, phosphorus and vitamin D metabolism were examined in 21 male and 13 female subjects with renal tubular dysfunction in the cadmium-polluted Jinzu River basin in Toyama prefecture, Japan. Multiple proximal renal tubular dysfunction was detected in all subjects showing increased FE beta 2-m and FFua, generalized aminoaciduria and renal glucosuria. Reduced ability of tubular reabsorption of phosphate resulted in hypophosphatemia in 31% of the women. Despite decreased tubular reabsorption of calcium, the level of serum calcium remained normal in all subjects. Serum 1,25-dihydroxyvitamin-D [1,25(OH)2D], which is produced in the proximal tubules through 1 alpha-hydroxylation from 25-hydroxyvitamin-D [25OHD], was normal or increased to more than 60pg/ml. The serum level of 1,25(OH)2D was inversely related to creatinine clearance in both the men (p < 0.05) and women (p < 0.01). Serum iPTH was slightly increased to more than 0.9 mg/ml, whereas the levels of other hormones, including 25OHD, calcitonin, thyroxine (T4) and triiodothyronine (T3) were normal. The serum alkaline phosphatase activity and serum osteocalcin concentration were significantly increased compared to those of controls in both sexes. Bone loss detected by the measurement of bone density was prominent in female subjects. These results support the hypothesis that the serum phosphate concentration is more important than the serum concentration of 1,25(OH)2D for abnormalities of bone metabolism in cadmium-induced renal tubular dysfunction.

[Sugi (Cryptomeria japonica D. Don) pollen scattering out of season]

We investigated the preseasonal blooming conditions of the male flowers of Sugi (Cryptomeria japonica D. Don) which flowers commonly in spring. We also investigated atmospheric Sugi pollen during all seasons for three years from 1988 through 1991 to determine pollen scattering in autumn. Our results showed that a discernible amount of pollen is scattered from the middle of October into December; this scattering would be expected in the following spring. Almost none of the buds of the flowers collected in October and in November bloomed when incubated at temperatures ranging from 6 degrees C to 20 degrees C after low-temperature treatment to arise the blooms from dormancy. However, small numbers of the male flowers from various Sugi trees bloomed and scattered pollen under these conditions. We found that the ratio of the blooming male flowers was one-third or less per blossom. The ratio changed depending on the growth stage and incubation conditions. In conclusion, the density of airborne Sugi pollen scattering is not high in autumn in general. However, the density would be expected to be high enough to induce allergic reactions and clinical symptoms in some areas of Sugi growth, especially in a good harvest year.

[Prediction of the day on which sugi (Cryptomeria japonica D. Don) pollen scattering will begin--from view point of plant physiology]

We investigated the cumulative thermal constant and threshold temperature for the development of sugi (Cryptomeria japonica D. Don) male flowers to predict the day on which pollen scattering would begin. The threshold temperature for the development of sugi male flowers was 0.17 degrees C and the cumulative thermal constant was 184 degrees C/day. Using these results, we determined how long it would take for sugi to be awaken from dormancy and we investigated the meteorological date. Reactivation from dormancy requires 3 days, where the minimum temperature is less than 3 degrees C with a mean temperature of less than 6 degrees C; the following day must have a maximum temperature of more than 10 degrees C, and these conditions must be maintained for at least 2 days. From these results, it is not difficult to predict the day on which sugi pollen scattering will begin.

[Study of an outbreak of itai-itai disease]

We studied an outbreak of itai-itai disease in the Jinzu River basin, in Toyama, Japan. One hundred and fifty females recognized as itai-itai disease patients till by 1990 were studied for the ages and years of onset and residence in the cadmium-polluted area. 1. Cases were recognized from as early as 1929, increased gradually to the peak of 1955-1959 and rapidly decreased up to the 1970s. 2. It was found that the later the patients was born, the younger the age of onset, though there was no difference of ages of onset between the cases born in the 1910s and the cases born from 1920. 3. The onset of itai-itai disease was most frequently seen at 50-59 years of residence in the cadmium-polluted area. It was found that the later a person started to inhabit the cadmium-polluted area, the shorter the period of residence in the cadmium-polluted area up to onset of itai-itai disease. 4. Comparing the patients who inhabited the cadmium-polluted area from birth and those who had moved there from non-polluted areas, the age of onset was higher in the latter, but there were no significant differences in the period of residence up to onset. From these findings, it appeared that itai-itai disease was not caused by aging, but by cadmium exposure starting from the 1910s.

[Relationships between the pollen productions in sugi (Cryptomeria japonica D. Don) forests and the patterns of atmospheric scattering pollens in Toyama Prefecture--the example of Toyama Prefecture in 1990]

We investigated the geographical distribution of sugi (Cryptomeria Japonica D. Don) forests and the male flower-setting conditions of them in Toyama prefecture. The relationships between our findings and the atmospheric pollen scattering patterns were also studied. The results were as follows. 1. Atmospheric pollen counts and their scattering patterns were fairly easily explained by the geographical distribution of 30-year old sugi forests, the male flower-setting conditions and the first day pollen was scattered in those forests. 2. Total atmospheric counts and maximum sugi pollen peaks were significantly affected by the proximity of sugi forests at altitudes of less than 200 meter. 3. In the atmospheric pollen survey, the detected pollen counts decreased according to the distance between the observation sites and the sugi forests. And few pollen grains were observed from natural sugi forests growing at distances of 20 km to 30 km from the observation sites.

[Evaluation of qualitative and quantitative tests for proteinuria and glucosuria as screening tests for cadmium-induced renal tubular dysfunction]

To evaluate the screening tests for cadmium-induced renal tubular dysfunction, qualitative and quantitative tests for urinary protein and glucose have been done in 146 urine samples obtained from subjects who had lived in the cadmium-polluted Jinzu River basin in Toyama Prefecture, Japan. The subjects consisted of 66 men and 80 women aged 55 to 71 years with beta 2-microglobulinuria exceeding 1,000 micrograms/g creatinine. The results obtained from this study were as follows; 1) The positive reaction (above 1+) for protein by the dipstick method was seen in 19.7% of men and 20.0% of women, and for glucose using Tes-tape in 48.5% of men and 33.8% of women. 2) The geometric means of protein and glucose concentrations in urine were 16.4 mg/dl and 12.7 mg/dl in men, and 14.2 mg/dl and 6.8 mg/dl in women, respectively. 3) The criteria of the primary screening in the health survey system for the residents in cadmium-contaminated areas conducted by the Japan Environment Agency were a proteinuria level exceeding 10 mg/dl and a glucosuria above (+/-) with Tes-tape. Nearly all subjects with urinary beta 2-microglobulin exceeding 30 mg/g creatinine were screened by these criteria in both sexes, whereas only 52.9% of men and 30.0% of women who had urinary beta 2-microglobulin between 10 to 30 mg/g creatinine could be screened in this manner. These results indicate that semiquantitative tests are insufficient as initial tests for screening cadmium-induced renal tubular dysfunction.

Impaired urine concentrating ability in Itai-itai (ouch-ouch) disease

A case of Itai-itai (ouch-ouch) disease with reduced urinary kallikrein excretion and slightly enhanced renin-angiotensin-aldosterone system is described. Although it is well known that cadmium toxicity frequently affects the renal tubular lesions, this report is the first to demonstrate the impaired urine concentrating ability in this disease.

Determination of human aspartate aminotransferase isoenzymes by their differential sensitivity to proteases

The effect of various proteases (trypsin, chymotrypsin, subtilisin, protease 401, and thermolysin) on the mitochondrial isoenzyme (m-AST) and cytoplasmic isoenzyme (c-AST) of human and swine aspartate aminotransferase (AST;EC 2.6.1.1) was evaluated. All procedures including the reaction with proteases and the subsequent determination of the AST activity were carried out in an automatic analyzer. The mammalian c-AST was efficiently inactivated by chymotrypsin, subtilisin and protease 401 while m-AST activity decreased very slowly with these proteases. Thermolysin and trypsin showed much less effect on c-AST activity. Especially, chymotrypsin at concentrations of 0.5-1.0 g/L inactivated human c-AST almost completely but showed no detectable inactivating effect on m-AST. Thus chymotrypsin appears to be the most suitable protease for the differential determination of AST isoenzymes in human serum. Further studies on the effects of proteases with AST from other species showed that Escherichia coli AST resembled mammalian m-AST while Pseudomonas AST resembled c-AST.

Urinary trehalase activity as an indicator of kidney injury due to environmental cadmium exposure

One hundred and seventy-eight subjects, patients with Itai-itai disease and their family members, aged 12-87 years living in a cadmium (Cd)-polluted area in the Jinzu River basin (Cd-exposed group) and 176 controls (control group) were examined. In the Cd-exposed group urinary trehalase increased with increasing age, urinary beta 2-microglobulin (beta 2-m) and retinol-binding protein. Although urinary cadmium was higher in the Cd-exposed group, no particular correlation was found between urinary trehalase and urinary cadmium. Seventeen men and 11 women showed raised urinary trehalase activities despite normal values of urinary beta 2-m (less than 300 micrograms/g.creatinine), suggesting that urinary trehalase increases earlier than urinary beta 2-m. In 19 patients with Itai-itai disease included in the Cd-exposed group, urinary trehalase decreased with decreasing reciprocal of serum creatinine, suggesting that urinary trehalase decreases in the most advanced cases of chronic cadmium nephropathy due to reduced tubular cell mass.

Diffuse midperipheral acute retinal pigment epitheliopathy

We examined a 16-year-old boy with a remarkable decrease in vision OS. Typical lesions of acute retinal pigment epitheliitis (Krill's disease) were not present in the macula but were diffuse in the midperiphery. Angiographic findings were similar to those in Krill's disease. The left fundus returned to normal two weeks later, but ten months passed before electro-oculography, light sensitivity, and dark adaptation were normal. Thus, there may be two types of acute retinal pigment epitheliitis: one is Krill's disease, and the other is a vast disturbance in the retinal pigment epithelium.

Elevation of urinary trehalase activity in patients of itai-itai disease

The elevation of urinary trehalase activity in patients of itai-itai disease was examined. Urinary trehalase was correlated with tubular reabsorption of phosphorus (%TRP): the lower the trehalase activity, the worse was %TRP. Furthermore, this activity was inversely correlated with urinary glucose and urinary total protein. In itai-itai disease, the excretion of beta 2-microglobulin seems to be maximal, and urinary trehalase activity was low in the latter stages of the disease. It is inferred that itai-itai disease produces extremely severe tubular damage as well as glomerular dysfunction.

Phage patterns of Staphylococcus hyicus subsp. hyicus isolated from chickens, cattle and pigs

Bacteriophage typing was performed on 285 strains of Staphylococcus hyicus subsp. hyicus isolated from pigs, chickens, and cattle, using the 5 S. hyicus subsp. hyicus phages, S9, S13, S39, S188 and CH11. One hundred and twenty-eight (64.3%) of the 199 swine strains, 62 (100%) of the 62 chicken strains, and 24 (100%) of the 24 cattle strains were typable at either routine test dilution (RTD) or 100 X RTD. Most (124/128) of the typable swine strains showed phage patterns consisting of lytic reactions with one or more of the phages S9, S13, S39 and S188. Phage patterns including phage CH11 were detected in only 4 swine strains. All of the typable chicken strains showed phage patterns consisting of lytic reactions with phage CH11. Cattle strains had the phage patterns that were found most frequently in swine and chicken strains. This study suggested that phage typing might be a useful marker for distinguishing ecovars within S. hyicus subsp. hyicus.

Muscle tone and drug sensitivity of isolated bovine iris sphincter are enhanced at low temperatures

The effects of temperature on nerve-mediated or carbachol-induced contractions of isolated bovine iris-sphincter muscles were studied. A decrease in temperature (to below 36 degrees C) led to contraction of the iris sphincter. The contractile responses induced by intramural cholinergic nerve stimulation were augmented by moderate cooling (29 degrees-31 degrees C), but were markedly inhibited by severe cooling (less than 22 degrees C). On the other hand, after cooling the contractile amplitude induced by carbachol (3 X 10(-7) M) was enhanced to 258% +/- 16% (29 degrees-31 degrees C), and 185% +/- 12% (20 degrees-21 degrees C) of control levels. Whereas the cooling-induced development of muscle tone was inhibited by the presence of indomethacin and FPL-55712, the application of prostaglandins (10(-9) to 3 X 10(-8) M) led to restoration of the sensitivity of the muscle observed at low temperatures. As low temperatures increase the response of bovine iris-sphincter muscle, temperature might affect the state of the iris during intraocular clinical surgery and in cases of intraocular inflammation.

Urinary trehalase activity and renal brush-border damage in inhabitants of a cadmium-polluted area (Jinzu River basin)

Elevated urinary trehalase activity was observed in the inhabitants of the Jinzu River basin. Urinary trehalase activity was correlated with other urinalysis components, such as beta 2-microglobulin, glucose, amino nitrogen, and cadmium, of which a high level was observed in cadmium-polluted areas as compared with the reference area. Renal trehalase is specifically localized in tubular brush borders [M. Nakano, J. Histochem. Cytochem., 30 (1982) 1243-1248]. From these results it is inferred that tubular brush-border damage occurs in inhabitants of the Jinzu River basin.